JP2006284728A - Development apparatus and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a development apparatus that can be reduced in size and made inexpensive, with a longer lifetime for a development device member, such as a developer carrier, that can prevent development ghosts, afterimages or degrading in solid image follow-up properties, and that can prevent image defects, such as black and white stripes and density irregularities, and to provide an image forming method. <P>SOLUTION: The apparatus is equipped with a destaticizing member 5 in an electrically floating state, in a region from the downstream side of a developing zone 30 to a charging member 6 along the moving direction of the surface of a developer carrier 2, the surface of the destaticizing member 5 or the member itself made of a material exhibiting polarity in the same polarity side as the normal charging polarity of a developer (toner) than the developer on an electrostatic charge sequence. Charges of the toner on the developer carrier 2, after development, are destaticized by the destaticizing member 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a developing device that develops an electrostatic latent image formed on an electrostatic latent image bearing member into a visible image in an electrophotographic apparatus such as a copying machine or a printer. In particular, the toner supplied to the developer carrying member whose surface moves is passed between the toner regulating member (charging member) contacting the surface and the surface to hold the toner as a thin layer of charged toner on the surface. The present invention relates to a one-component developing device that is transported to a developing region, used for development, and returns to the toner supply side while remaining on the developer carrying member without being consumed after development.

  An image forming apparatus employing an electrophotographic system such as a copying machine or a printer is provided with a developing device for developing an electrostatic latent image formed on the surface of an image carrier.

  In recent years, in response to a request for downsizing of an image forming apparatus, downsizing of the developing apparatus has been strongly demanded, and a technique for ensuring the developing performance at that time is required.

  For example, a developer bearing member of a magnetic brush type that transports a two-component developer composed of toner and a magnetic carrier to a developing region facing the image bearing member using magnetic force is developed, and the developer is developed after development. A developing device that can be recovered into a tank has been put into practical use.

  In order to stabilize the development in this method, it is necessary to replenish consumed toner and control the ratio of the toner contained in the developer, that is, the toner concentration to be constant.

  Usually, in the developing device using the magnetic brush developing method described above, the proportion of the carrier in the developer is larger, the developing tank for storing the developer becomes larger, and the developing device tends to be larger as a whole. In addition, it is necessary to control the toner concentration, and at the same time, a stirring member or the like for making the charge amount of the toner in the developer constant is necessary. It was.

  On the other hand, in recent years, a developing apparatus that performs development using a one-component developer, that is, a toner that is a one-component developer having no carrier, has been proposed and put into practice. In the developing device using such a one-component developer, it is not necessary to control the toner concentration, and the volume of the developing tank can be greatly reduced by the absence of the carrier, and thus the size of the developing device can be reduced. In accordance with this, the simplicity of maintenance and the like is also excellent. In other words, since there is no need to replace the developer due to the deteriorated developer, particularly the carrier, maintenance for the replacement becomes unnecessary. Further, it is only necessary to replenish the toner, it is not necessary to detect the toner density, and control for that purpose is not required. In particular, in a developing device using a one-component toner, it is only necessary to replenish the toner when necessary. In particular, when no magnetic toner is used, a magnet roller is not used, so that a small and inexpensive device capable of developing clearly can be realized.

  In a developing device using a non-magnetic one-component toner, an image carrier that carries an electrostatic latent image and a developer carrier that carries a developer (toner) are arranged to face each other in a non-contact state, and an alternating electric field is generated between them. A non-contact type developing device that develops the toner by reciprocating and applying toner, and a developer carrier and an image carrier made of a conductive elastic body are placed opposite to each other so that a voltage is applied to the developer carrier. It is roughly classified into a contact-type developing device that applies and develops. The non-contact type apparatus mainly uses a developing bias voltage obtained by superimposing an AC voltage on a DC voltage, and the contact type apparatus mainly uses a DC developing bias voltage. However, as in the non-contact type, the AC voltage is superimposed. In some cases.

  Such a conventional one-component developing device has, for example, the configuration described in (Patent Document 1), a schematic diagram of the conventional developing device in FIG. A description will be given with reference to schematic views illustrating detailed steps of the charging (thinning) portion.

  In this one-component developing device, a one-component developer (toner) 7 is accommodated in a developer (toner) hopper 34 opened to the developing region 30 side. Agitator supply member 4 such as an agitator or a screw supplied near the agent supply member (supply roller) 3, the surface moves, the developer 7 is carried to the development region 30, and the image carrier 1 carrying the electrostatic latent image is carried. A developer carrier 2 that performs a developing operation, a developer supply member 3 that supplies developer (toner) to the developer carrier 2 in a developer supply region, and the supplied toner 7 are brought into contact with the surface of the developer carrier 2. From the downstream side of the developing region 30 in the direction of surface movement of the developer carrier 2, the charging member (layer regulating member) 6 that makes the surface of the developer carrier 2 pass through between the developer carrier 2 and the surface of the developer carrier 2. Located in the region reaching the layer regulating member 6, developer A neutralizing member 105 that contacts a part or all of the surface of the developer carrying member in a direction crossing the surface movement direction of the carrier 2 is provided, and the developer carrying member 2 has a power supply 9 for supplying a developing bias voltage, a developer supply The member 3 has a power supply 11 for supplying a voltage to the developer supply member 3, the charging member 6 has a power supply 10 for supplying a charging member voltage, the charge removing member 105 has a power supply 112 for supplying a voltage to the charge removing member, Between the charge eliminating member 105 and the developer carrying member 2, there is provided a backup sponge 113 or the like for firmly pressing the charge removing member 105 against the developer carrying member 2.

In this configuration, the static elimination member 105 is a plate-like elastic member, for example, any one of a mixed resin of PC and PBT, a fluorine-containing resin such as nylon, PET, and PTFE, a silicon-containing resin, polyurethane, and PVDF. The base material is made of a material in which one or more of carbon black, conductive fine particles, TiO ₂ or the like is appropriately mixed, and the thickness is 0.3 mm ± 0. 2 mm, the electric resistance value is 10 ⁻⁵ to 10 ⁶ Ω, and the nip with the developer carrier 2 is set to 0.5 to 1 mm. In addition, the resistance value Rt of the toner layer on the developer carrier 2 and the resistance value Rd of the charge removal member are set to be approximately the same. Further, the current I required for charge removal is such that the toner mass per unit area of the toner layer on the developer carrying member 2 after passing through the charging member 6 is m / a, and the charged charge amount of the toner 7 is Q / M is the charge change amount of the toner layer on the developer carrier 2 after passing through the developing region 30, that is, the toner charge amount changed by the pressure contact with the image carrier 1 is ΔQ / M, and the developer carrier 2 It is preferable that I ≧ − (m / a) · (Q / M + ΔQ / M) · Vt · WC when the rotation speed is Vt and the effective static elimination width of the static elimination member 105 is WC.

  Further, when the applied voltage is determined in consideration of the electric resistance values of the developer carrying member 2, the charge removal member 105, and the toner layer, V = IR in order to realize the supply of the charge removal current I with the constant voltage power source 112. Therefore, the DC applied voltage from the electricity removing member power supply 112 to the electricity removing member 105 is Vj, the DC applied voltage from the developer carrier power supply 9 to the developer carrier 2 is Vb, When the electric resistance value is Rd, the electric resistance value of the toner layer is Rt, and the electric resistance value of the developer carrier 2 is Rr, (Vd−Vr) ≧ − (((m / a) · (Q / It is preferable to apply a potential difference (Vd−Vr) that satisfies (M + ΔQ / M) · Vt · WC) · (Rd + Rt + Rr)).

  The operation of the conventional developing device configured as described above will be described.

  One-component toner 7 is accommodated in the toner hopper 34 opened to the developing region 30 side. The toner 7 is agitated by an agitation supply member 4 such as an agitator or a screw and is supplied in the vicinity of the developer supply member 3. The developer supply member 3 that rotates in the same direction as the rotation direction of the developer carrier 2 is brought into contact with, for example, pressure contact with, the developer carrier 2. A predetermined bias voltage Vs is applied to the developer supply member 3 by a connected power source 11. The voltage Vs is set so as to electrically move the toner 7 in the direction of the developer carrying member 2. For example, when negative polarity toner is used, a voltage Vs having a larger potential is applied to the negative electrode side. The toner 7 is effectively supplied to the developer carrier 2 by being charged by charge injection due to a potential difference between the developer carrier 2 and the developer supply member 3 and frictional charging at the contact portion between the two bodies 23. The The toner 7 adhering to the developer carrier 2 is conveyed to the vicinity of the charging member (layer regulating member) 6 provided on the upstream side of the developing region 30 in the rotation direction of the developer carrier. For example, the charging member 6 is made of a plate-shaped metal material, and the developer carrier side surface near the tip of the one end or near the tip is pressed against the developer carrier 2, and the other end is the toner hopper 34. Fixed to the top. A predetermined bias voltage Vd is applied to the charging member 6 from the power supply 10. As a result, the toner layer on the developer carrier 2 is charged to a predetermined charge amount and formed to a predetermined thickness. The toner 7 adhering to the developer carrier 2 is conveyed to the development area 30 to visualize the electrostatic latent image on the surface of the image carrier 1.

  The toner 7 remaining on the developer carrying member 2 that has passed through the developing region 30 is conveyed to the vicinity of the charge eliminating member 105 provided on the downstream side of the developing region 30 in the rotation direction of the developer carrying member. The neutralizing member 105 is fixed to the lower portion of the toner hopper 34 by using, for example, a backup sponge 10.3 so as to be in pressure contact with the developer carrier 2. A predetermined bias voltage Vj is applied to the charge removal member 105 from the power source 112. The bias voltage Vj is a DC or AC voltage as will be described later. The charge of the toner 7 is removed by such a charge removal member 105. Further, the developer supply member 3 whose movement direction is reversed at the contact point with the roller 2 is pressed against the developer carrier 2, whereby the toner 7 is separated from the developer carrier 2, and the toner hopper It is collected in 34 and reused. An image is repeatedly formed by such a process.

However, according to the disclosure of (Patent Document 1), the electric resistance value of the static elimination member is 10 ⁻⁵ to 10 ⁶ Ω and the electric resistance value of the toner layer on the developer carrying member (about 10 ⁶ to 10 ⁹ Ω). Due to the lower resistance, an excessive potential difference occurs between the static elimination member and the developer carrying body, an overcurrent flows, a discharge phenomenon occurs, the toner deteriorates, and the static elimination member and the developer carrying There is a problem such as deterioration of a developing member such as a body. The electric resistance value of the charge eliminating member and the toner is the same, but the electric resistance value is 10 ⁶ to 10 ⁹ Ω (toner layer thickness is 0.4 to 1.3 mg / Cm ² ) on the developer carrying member. There is no problem when the toner layer is present, but when the toner layer is thin or almost absent after development, there is an excessive potential difference between the portion of the developer carrying member that has little or almost no toner and the static elimination member. As a result, an overcurrent partially flows, a discharge phenomenon occurs, the toner is deteriorated, and a developing device member such as a charge eliminating member or a developer carrying member is deteriorated.

  Further, even if there is no excessive potential difference between the static elimination member 105 and the developer carrier 2, the developer (toner) 19 staying and fixing in the nip portion or the vicinity of the static elimination member 105 in FIG. Even if there is only a small potential difference, the weakly charged toner 7 on the developer carrying member 2 has a force to move toward the charge removing member 105, and the weakly charged toner 7 has a weak holding force on the developer carrying member and is easily peeled off. As time passes, the weakly charged toner 7 is adsorbed or accumulated and stuck to the nip portion or the vicinity of the neutralization member 105, and the developer carrier 2 is damaged by the stuck toner mass. Furthermore, excessive charge removal increases the above-described weak charge, and thus accelerates the staying and fixing of the toner 7 on the charge removal member 105 described above.

  Further, if the charge removal current is equal to or greater than the toner layer current value on the developer carrying member, the charge removal effect is sufficiently obtained and no afterimage is generated. However, the charge due to frictional charging between the charge removal member 105 and the toner 7 is actually performed. There is a movement, which is not taken into account in this (Patent Document 1), and tends to be excessively set (about −10 to −100 μA) than the actual required static elimination current, and a sufficient static elimination effect is obtained. As described above, an overcurrent partially flows between the charge eliminating member 105 and the developer carrying member 2, or a discharge phenomenon occurs, causing the toner 7 to deteriorate, developing the charge removing member 105, the developer carrying member 2, and the like. There is a problem of deteriorating the vessel member. Further, even if there is a slight potential difference between the charge eliminating member 105 and the developer carrying member 2, the weakly charged toner on the developer carrying member 2 acts to move toward the charge removing member 105, and the weakly charged toner is used as the developer. Since the holding force to the carrier is weak and easily peeled off, the weak charge is adsorbed or accumulated and stuck to the nip portion or the vicinity of the neutralizing member 105 over time, and the developer carrier 2 is damaged by the stuck toner mass. Have. If the neutralizing effect is too high, a large amount of reverse polarity and weakly charged toner is produced, and density unevenness due to unevenness of the toner layer thickness on the developer carrier 2 is generated, or these reverse polarity and weakly charged toner are used as a developer supply member. The developer supply member 3 is hardened, and the developer supply member 3 scrapes the developer carrier 2 or discharges the developer carrier by the developer supply member 3 excessively after static elimination. 2 After the toner is supplied from the developer supply member 3 to the developer carrier 2 in order to scrape the toner on the top, there is a large amount of uncharged toner from the toner hopper 34 and the charge amount of the toner 7 is low. Since the toner carrying force of the agent carrier 2 itself becomes weak, as shown in FIG. 13, the developer (toner) 19 staying and fixing in the vicinity of the nip portion of the charging member 6 is weakly charged, reverse polarity, uncharged toner, etc. Due to weakly charged, reverse polarity, uncharged toner, etc. Flocculation product tends to be caught by the charging member 6, has a problem that white streaks are generated on the image.

  Further, the external additive of the developer (toner) 7 has a great influence on the charging characteristics and fluidity of the developer 7, and it is necessary to optimize it according to the image quality and life such as uniformity and solid followability. There is a problem that will be described later if it is excessive.

  In this (Patent Document 1), there is no specific provision for the coverage of a clear external additive (silica or the like). Therefore, even if the image quality can be optimized, the external additive is excessively contained, and the developer 7 There are cases where a large amount of silica, etc. (external additive) that has been detached, liberated or aggregated is contained. In this case, the desorbed / free / aggregated silica or the like (external additive) is weakly charged, reversely charged, or agglomerated and aggregated in the same manner as the above-described reversed polarity and weakly charged toner. Since the conveying force in the developer carrier 2 is extremely small, such as particles, even if there is a slight potential difference between the charge removal member 105 and the developer carrier 2, Weakly charged particles (detached / free / aggregated silica, etc.) act to move toward the static elimination member 105, and weakly charged particles have weak holding power to the developer carrying member 2 and are easily separated (particularly aggregated). Silica, etc.), weakly charged with time or adsorbed or stayed and stuck to the nip portion or the vicinity of the static elimination member 105, and the toner 7 is also fixed and grows into a toner lump with the fixed portion as a nucleus, and the toner lump develops. There is a problem that the agent carrier 2 is damaged. In addition, the opposite electrode and weakly charged particles (such as desorption / free / aggregated silica) may cause density unevenness due to uneven toner layer thickness on the developer carrier 2, or the opposite electrode and weakly charged particles (detachment).・ A large amount of free / aggregated silica or the like) enters the eye of the developer supply member, hardens the developer supply member 3, and the developer supply member 3 scrapes the developer carrier 2 or weakly charges / reversely. Charged / aggregated particles (desorbed / free / aggregated silica, etc.) have a weak conveying force on the developer carrying member 2 (particularly, aggregated into large particles). As shown in the figure, the developer (toner) 19 staying and adhering to the vicinity of the portion is likely to be caught by the charging member 6 due to weakly charged, reverse polarity, uncharged silica or the like, or weakly charged, reverse polarity, uncharged silica or the like. The toner 7 is solidified with the external additive such as silica as a core. Grown, has a problem that white streaks are generated on the image at that part. This black and white streaks due to silica and the like was found to be a toner whose main component was an external additive such as silica when analyzed on what was fixed to the static eliminator of the developing device where the black and white streaks actually occurred and when it was fixed to the charging member. Therefore, it is clear that excessive silica or the like (external additive) is a factor. On the other hand, if the external additive coverage is too small, the charging characteristics and fluidity of the toner 7 are lowered, and the image uniformity and the solid followability are lowered.

  Further, since there is no specific regulation in the pressing force between the static elimination member 105 and the developer carrier 2, the toner remaining on the development carrier 2 after development due to excessive application of the static elimination member 105 to the developer carrier 2. The charge of 1.4 may be excessively discharged. For this reason, a large amount of reverse polarity and weakly charged toner is produced to cause density unevenness due to unevenness of the toner layer thickness on the developer carrying member, or these reverse polarity and weakly charged toner are in the eyes of the developer supply member 3. The developer supply member 3 is hardened, and the developer supply member 3 scrapes the developer carrier 2, or after the charge is removed, the developer supply member 3 scrapes off the toner on the developer carrier 2 excessively. Therefore, after the toner is supplied from the developer supply member 3 to the developer carrier 2, the amount of uncharged toner from the toner hopper 34 is large and the charge amount of the toner 7 is low. Since the toner conveying force of the toner is weak, softly charged, reverse polarity, uncharged toner, etc. or soft aggregates due to weakly charged, reverse polarity, uncharged toner, etc. are easily caught on the charging member 6 and white streaks are generated on the image. It has a problem. In addition, if it is applied too strongly, there is an excess of static elimination, but there may be a problem that the toner layer on the developer carrier 2 cannot pass through the static elimination member 105, or due to friction at the nip portion between the static elimination member 105 and the developer carrier 2. Heat is generated, the toner is deteriorated, or the toner is fused to the nip surface of the charge removal member 105 or the developer carrier 2, thereby damaging the developer carrier 2 and causing image defects such as streaks and uneven density. There is a problem that causes. On the other hand, when the static elimination member 105 is weakly applied to the developer carrier 2, there is a problem that the static elimination effect is low and an afterimage is generated. In this case, a potential difference is provided between the static elimination member 105 and the developer carrier 2 as much as the electrical resistance of the static elimination member 105, the toner layer on the developer carrier 2, and the electric resistance of the developer carrier 2 and the charge amount of the toner layer. However, when the pressing force of the static elimination member 105 is weak, unless the static elimination member 105 having a high frictional charging capability is used, in order to enhance the static elimination effect, an excessive amount between the static elimination member 105 and the developer carrier 2 is used. Since a potential difference must be provided, there is a problem that electric discharge is likely to occur between the static elimination member 105 and the developer carrier 2 and various members are deteriorated. Furthermore, an excessive potential difference between the charge eliminating member 105 and the developer carrying member 2 increases the force that the weakly charged toner on the developer carrying member 2 moves toward the charge removing member 105, and the weakly charged toner is loaded with the developer. Since the holding power to the body 2 is weak and easily peeled off, the problem is that the weakly charged toner is adsorbed or accumulated and stuck to or near the nip portion of the static elimination member 105 over time, and the developer carrying body 2 is damaged by the stuck toner mass. It will accelerate. This also has the problem that the charge removal effect is too high or too low due to the frictional charging characteristics of the charge removal member as described above.

  Further, according to the disclosure (Patent Document 1) in order to produce a charge removal effect, a predetermined potential is applied to the charge removal member 105 and a potential difference is provided between the charge removal member 105 and the developer carrier 2. Is determined only by the resistance value of the toner on the developer carrier 2, the charge removal member 105, the developer carrier 2, and the like, and the charge amount of the developer (toner) 7 on the developer carrier 2. The charging ability is not considered. Since the charge eliminating member 105 has different charging ability depending on the material selected, for example, when the electric resistance of the charge eliminating member 105, the toner 7 and the developer carrier 2 is increased even though the charge ability is high, an excessive potential difference is taken. Therefore, the toner on the developer carrier 2 is excessively discharged, and a large amount of reverse polarity and weakly charged toner is produced, causing density unevenness due to uneven toner layer thickness on the developer carrier 2, These reverse and weakly charged toners enter a large amount into the eyes of the developer supply member 3 to harden the developer supply member 3, and the developer supply member 3 scrapes the developer carrier 2, or after static elimination. After the toner is supplied from the developer supply member 3 to the developer carrier 2 in order to scrape off the toner on the developer carrier 2 by the developer supply member 3, the uncharged toner from the toner hopper 34 Tona 7 has a low charge amount, and therefore the toner carrying force of the developer carrier 2 itself is weakened. Therefore, softly agglomerated particles such as weakly charged, opposite polarity, uncharged toner, and weakly charged, opposite polarity, uncharged toner are charged. There is a problem that the member 6 is easily caught and white streaks are generated on the image. Further, due to the potential difference between the developer carrying member 2 and the charge eliminating member 105, the weakly charged toner on the developer carrying member 2 moves toward the charge removing member 105, and the weakly charged toner is applied to the developer carrying member 2. Since the holding power is weak and easily peeled off, there is a problem that the weakly charged toner is adsorbed or accumulated and stuck to the nip portion or the vicinity of the static elimination member 105 over time, and the developer carrying body 2 is damaged by the stuck toner mass.

Further, there is no problem when there is a toner layer having an electric resistance value of 10 ⁶ to 10 ⁹ Ω (toner layer thickness of 0.4 to 1.3 mg / Cm ² ) on the developer carrier 2, but the toner layer after development Is thin or almost absent, it is difficult to maintain a predetermined potential difference between the developer carrying member 2 and the charge eliminating member 105, and there is little or almost no toner on the developer carrying member 2 between the charge removing member 105. Therefore, there is a problem that an excessive potential difference occurs, an overcurrent flows, a discharge phenomenon occurs, the toner is deteriorated, and the developer member such as the charge eliminating member 105 or the developer carrier 2 is deteriorated. It was.

Further, since the electric resistance of the static elimination member 105 is as low as 10 ⁻⁵ to 10 ⁶ Ω, the potential difference between the static elimination member 105 and the developer carrier 2 when the resistance values of the developer carrier 2 and the toner 7 are high. If there is almost no toner on the developer carrier 2 after development, the potential difference between the developer carrier 2 and the charge removal member 105 may become excessively large, as described above. Overcurrent flows between the charge eliminating member 105 and the developer carrying member 2, a discharge phenomenon occurs, the toner deteriorates, and the developing member such as the charge removing member 105 and the developer carrying member 2 deteriorates. Have Furthermore, an excessive potential difference between the charge eliminating member 105 and the developer carrying member 2 increases the force that the weakly charged toner on the developer carrying member 2 moves toward the charge removing member 105, and the weakly charged toner is loaded with the developer. Since the holding force to the body 2 is weak and easily peeled off, the problem is that the weakly charged toner is adsorbed or accumulated and stuck to or near the nip portion of the static elimination member 105 over time, and the developer carrying body 2 is damaged by the stuck toner mass. It will accelerate.

  Conversely, when the electrical resistance of the static elimination member 105, the toner 7, and the developer carrier 2 is low, the potential difference between the static elimination member 105 and the developer carrier 2 is supposed to be small. There is a problem that the toner on the developer carrier 2 is hardly discharged. Therefore, there is a problem that the static elimination member 105 is excessively neutralized or insufficiently neutralized depending on the size of the frictional charging ability of the static elimination member 105.

  Furthermore, since a potential difference is provided between the static elimination member 105 and the developer carrier 2, it is necessary to apply a potential to the static elimination member 105, so that an extra power source is necessary, which causes problems in cost and size reduction.

  Further, in the conventional developing method disclosed in (Patent Document 2), it is assumed that the charge removal member 105 is made of a material that is offset from the toner 7 in the same charge polarity as the normal charge polarity of the toner. The potential difference between the toner 105 and the developer carrying member 2 is provided. However, as described above, the frictional charging ability of the charge removal member 105 with the toner 7 is not considered as described above. Since there is no potential difference between the static elimination current value considering the ability and the static elimination member 105 and the developer carrier 2, excessive static elimination, insufficient static elimination, or excess between the static elimination member 105 and the developer carrier 2 There is a problem in that various potential members can be generated and various members such as the charge removal member 105 and the developer carrier 2 are deteriorated.

  Further, in order to solve these problems (Patent Document 3), after the developer carrying member 2 formed with a predetermined layer thickness of the developer 7 performs black image development, the developer 7 is supplied by the developer supply member 3. The average volume particle diameter of the developer 7 carried by the developer carrier 2 when the developer layer regulating member (charging member) 6 is again formed to have a predetermined layer thickness is Dbk, and the developer 7 is a predetermined amount. After the developer carrying member having the layer thickness is subjected to white image development, the developer is supplied by the developer supplying member, and the developer carrying member 2 is formed to have a predetermined layer thickness again by the charging member 6. When the average volume particle size of the developer 7 carried is DWt, the afterimage and ghost of development can be eliminated by satisfying DWt / Dbk> 0.8. According to this, when developing, particle size selection is Since not happen, it is necessary to the particle size and charge distribution of the developer (toner) 7 fairly sharp cost considerably toner production to classification or the like is such a problem. In addition, even with the toner produced in this manner, the contact type non-magnetic one-component developing method applies a considerable stress to the toner 7, and it is difficult to maintain a sharp particle size and charge amount distribution over time. There is a problem.

  Furthermore, there is a problem that there is no standard for preventing excessive static elimination and insufficient static elimination as described above.

Further, in (Patent Document 1), there is no specific provision in the peripheral speed ratio SR ratio of the developer supply member 3 to the developer carrier 2 according to the process speed. The developer carrier 2 itself and the toner on the developer carrier 2 are deteriorated, the toner 14 remaining on the developed carrier 2 after development is scraped off excessively, or the developer carrier 2 and the developer 7 are rubbed. There is a problem that is too much. Therefore, a large amount of reverse polarity and weakly charged toner is produced to cause density unevenness due to uneven toner layer thickness on the developer carrier 2, or these reverse polarity and weakly charged toner are The developer supply member 3 is hardened by melting the developer on the developer supply member 3 by frictional heat, and the developer supply member 3 scrapes the developer carrier 2 or is excessive after static elimination. After the toner 7 is supplied from the developer supply member 3 to the developer carrier 2 in order to scrape the toner on the developer carrier 2 by the developer supply member 3, uncharged toner from the toner hopper 34 is removed. In many cases, since the toner charge amount is low, the toner carrying force of the developer carrier 2 itself is weakened. Therefore, soft aggregates caused by weakly charged, reverse polarity, uncharged toner, etc. or weakly charged, reverse polarity, uncharged toner, etc. Is easily caught on the charging member 6, and the image It has the problem that the white streaks are generated in. If the SR ratio is too large, there is developer scraping and excessive friction by the developer supply member 3, but if the process speed is increased even if the SR ratio is constant, the rotation speed of the developer supply member 3 is increased and the developer is increased. If the amount of the developer member 7 in the supply member 3 is reduced, the developer supply ability is lowered, resulting in a problem that the solid followability is deteriorated, or conversely, when the SR ratio is excessively reduced, The problem of black and white streaks due to developer scraping by the developer supply member 3 and excessive friction is eliminated, but the supply capability from the developer supply member 3 to the development carrier 2 is simply lowered, and the solid followability deteriorates. There's a problem.
JP 11-288170 A JP-A-6-75469 JP 2000-10404 A

The problem (problem) to be solved is that since the electric resistance value of the static elimination member is 10 ⁻⁵ to 10 ⁶ Ω, which is lower resistance than the toner layer, an excessive potential difference between the static elimination member and the developer carrier. In other words, it is impossible to prevent an overcurrent from flowing partially, causing a discharge phenomenon, degrading toner, and degrading a developing device member such as a charge eliminating member or a developer carrying member.

In addition, although it is described that the electric resistance value of the static elimination member and the toner is the same, the toner on the developer carrier after development may be reduced or almost absent. When a toner layer having an electric resistance value of about 10 ⁶ to 10 ⁹ Ω (toner layer thickness of 0.4 to 1.3 mg / Cm ² ) is thin or hardly after development, the developer An excessive potential difference occurs between the part where the toner is little or hardly on the carrier and the static elimination member, an overcurrent flows, a discharge phenomenon occurs, the toner deteriorates, the static elimination member or the developer carrier part In particular, it is impossible to prevent deterioration of the developing device member.

  Further, even if there is no excessive potential difference between the static elimination member and the developer carrying member, even if there is a slight potential difference, the weakly charged toner on the developer carrying member acts to move toward the static elimination member. Since the charged toner has a weak holding power on the developer carrying member and is easily peeled off, the weakly charged toner is adsorbed or accumulated and stuck to the nip portion or the vicinity of the neutralization member with time, and the developer carrying member is damaged by the stuck toner mass. It is a point that cannot be prevented. Furthermore, excessive charge removal increases the above-mentioned weakly charged or reverse toner, so that the toner stays and adheres to the charge-removing member described above is accelerated, and damage to the developer carrying member cannot be prevented.

  Further, if the charge removal current is equal to or greater than the toner layer current value on the developer carrier, the charge removal effect is sufficiently obtained and no afterimage is generated. However, in reality, there is no charge transfer due to frictional charging between the charge removal member and the toner. However, this is not considered in the conventional developing apparatus, and since there is a tendency of setting excessively (approximately −10 to −100 μA) than the actual required static elimination current, a sufficient static elimination effect can be obtained. In addition, it is possible to prevent overcurrent from flowing partially between the charge eliminating member and the developer carrying member, causing a discharge phenomenon, degrading the toner, and degrading the developer member such as the charge removing member and the developer carrying member. This is not possible. Even if there is a slight potential difference between the charge eliminating member and the developer carrying member, the weakly charged toner on the developer carrying member acts to move toward the charge removing member, and the weakly charged toner is applied to the developer carrying member. Since the holding power is weak and easy to peel off, the weakly charged toner is adsorbed or stays and adheres to the nip portion or the vicinity of the static elimination member over time, and the developer carrying member is damaged by the stuck toner mass. If the charge removal effect is too high, a large amount of reverse polarity and weakly charged toner will be produced, causing density unevenness due to uneven toner layer thickness on the developer carrier, and these reverse polarity and weakly charged toner will be supplied by the developer. The developer supply member is hardened, and the developer supply member scrapes off the developer carrier, or after the charge removal, excessively scrapes the toner on the developer carrier by the developer supply member. Therefore, after the toner is supplied from the developer supply member to the developer carrier, there is a large amount of uncharged toner from the toner hopper, and the toner charge amount is low. Since it becomes weaker, softly agglomerates due to weakly charged, reverse polarity, uncharged toner, etc. or weakly charged, reverse polarity, uncharged toner, etc. are easily caught on the charging member, and it is not possible to prevent the occurrence of white streaks on the image. This is a problem to be solved.

  Further, the external additive of the developer (toner) has a great influence on the charging characteristics and fluidity of the developer, and it is necessary to optimize it according to the image quality such as uniformity and solid followability and the life. In the conventional developing apparatus, there is no specific provision regarding the coverage of the clear external additive (toner), so even if the image quality can be optimized, the external additive is excessively contained and the developer is removed. There are cases where a large amount of separated / free / agglomerated silica or the like (external additive) is contained, and the desorbed / free / aggregated silica or the like (external additive) is the same as the above-described reverse polarity and weakly charged toner. As described above, since the transport force in the developer carrier is extremely small, such as weakly charged, reversely charged, or agglomerated and large particles, the static elimination member and the developer carrier Even with a slight potential difference between them, weakly charged particles (desorbed / free / aggregated silica etc.) on the developer carrier Has a moving force toward the static elimination member, and weakly charged particles have a weak holding power to the developer carrying member and are easily peeled off (especially agglomerated silica). Therefore, there is a potential difference between the static elimination member and the developer carrying member. Even if not, the weak charge is adsorbed or stays and adheres to the nip portion or the vicinity of the static elimination member over time, and the toner adheres and grows into a toner mass using the adhered portion as a nucleus. The point of hurting is to be solved. In addition, the opposite electrode and weakly charged particles (such as desorption / free / aggregated silica) cause uneven density due to uneven toner layer thickness on the developer carrier, A large amount of free / aggregated silica or the like) enters the eye of the developer supply member, hardens the developer supply member, and the developer supply member scrapes the developer carrier, or weakly charged / reversely charged / aggregated particles. (Elimination / free / aggregated silica, etc.) has weak conveying power on the developer carrier (particularly, aggregated into large particles), so weakly charged, reverse polarity, uncharged silica, etc. Soft agglomerates due to charged, reverse polarity, uncharged silica, etc. are easily caught on the charging member, and the toner adheres and grows using the external additive such as silica as the core, and white streaks appear on the image at that portion. Is also a problem to be solved. On the contrary, if the external additive coverage is too small, the charging characteristics and fluidity of the toner are lowered, and the image uniformity and the solid followability are also to be solved.

  In addition, since there is no specific regulation in the pressing force between the charge eliminating member and the developer carrying member, the charge removing member is strongly applied to the developer carrying member to excessively charge the toner remaining on the developed carrying member after development. There are cases where static electricity is removed. Therefore, a large amount of reverse polarity and weakly charged toner is produced to cause density unevenness due to uneven toner layer thickness on the developer carrying member, or these reverse polarity and weakly charged toner are in the eyes of the developer supply member. The developer supply member hardens the developer supply member, and the developer supply member scrapes off the developer carrier or discharges the toner on the developer carrier excessively by the developer supply member after static elimination. After the toner is supplied from the supply member to the developer carrier, there is a large amount of uncharged toner from the toner hopper, and the toner charge amount is low, so the toner carrying force of the developer carrier itself becomes weak. In other words, soft agglomerates due to reverse polarity, uncharged toner, etc. or weakly charged, reverse polarity, uncharged toner, etc. are easily caught on the charging member, and white streaks cannot be prevented from occurring on the image.

  In addition, if it is applied too strongly, there will be excessive charge removal, but there will also be problems that the toner layer on the developer carrier cannot pass through the charge removal member, or heat will be generated due to friction at the nip between the charge removal member and developer carrier. There is also a problem that the toner is deteriorated or the toner is fused to the nip surface of the charge eliminating member or the developer carrying member, thereby damaging the developer carrying member and causing image trouble such as streak and density unevenness. It is a point that should be done. On the other hand, when the static elimination member is weakly applied to the developer carrying member, there is a problem that the static elimination effect is low and an afterimage is generated. In this case, there is a potential difference between the static elimination member and the developer carrier as much as the electric resistance of the static elimination member, the toner layer on the developer carrier, and the electric charge of the developer carrier and the charge amount of the toner layer. If the pressing force of the member is weak, unless a neutralizing member with high frictional charging capability is used, in order to enhance the neutralizing effect, it is necessary to have an excessive potential difference between the neutralizing member and the developer carrier. It is a point that electric discharge tends to occur between the charge removal member and the developer carrying member, and deterioration of various members cannot be prevented. Furthermore, the potential difference between the excess charge-eliminating member and the developer carrying member increases the force that the weakly charged toner on the developer carrying member moves toward the charge removing member, and the weakly charged toner is held on the developer carrying member. Since the force is weak and easy to peel off, it also solves the problem of weakly charged toner adsorbing or accumulating and adhering to the nip portion or the vicinity of the neutralization member over time and accelerating the problem of damaging the developer carrier with the adhered toner mass It is a point that should be done.

  This is also a point to be solved, as described above, that the static elimination effect is too high or too low due to the frictional charging characteristics of the static elimination member, and it is difficult to obtain an appropriate static elimination effect.

  Further, in order to produce a charge removal effect, a predetermined potential is applied to the charge removal member, and a potential difference is provided between the charge removal member and the developer carrying member. It is determined only by the resistance value of the developer carrier and the charge amount of the developer (toner) on the developer carrier, and does not take into account the charging ability of the charge removal member. Since the charge removal member has different chargeability depending on the material selected, for example, even if the chargeability is high, if the electric resistance of the charge removal member, toner, developer carrying member is increased, an excessive potential difference is taken. The toner on the developer carrier is excessively discharged, creating a large amount of reverse polarity and weakly charged toner, causing density unevenness due to uneven toner layer thickness on the developer carrier, Charged toner enters a large amount into the eyes of the developer supply member, hardens the developer supply member, and the developer supply member scrapes the developer carrier or discharges the developer excessively by the developer supply member. After the toner is supplied from the developer supply member to the developer carrier in order to scrape the toner on the carrier, there is a lot of uncharged toner from the toner hopper, and the charge amount of the toner is low. Own Since the toner conveying force becomes weak, softly charged, reverse polarity, uncharged toner, etc. or soft aggregates due to weakly charged, reverse polarity, uncharged toner, etc. are likely to be caught on the charging member, causing white streaks on the image. The point that cannot be prevented is also a problem to be solved. Also, due to the potential difference between the developer carrying member and the charge eliminating member, the weakly charged toner on the developer carrying member acts to move toward the charge removing member, and the weakly charged toner has a weak holding force on the developer carrying member and is peeled off. Therefore, it is also a problem to be solved that the weakly charged toner adsorbs or stays and accumulates and adheres to or near the nip portion of the static elimination member over time and damages the developer carrier with the adhered toner mass.

In addition, there is no problem when a toner layer having an electric resistance value of 10 ⁶ to 10 ⁹ Ω (toner layer thickness of 0.4 to 1.3 mg / Cm ² ) is present on the developer carrying member, If it is thin or almost absent, it is difficult to maintain a predetermined potential difference between the developer carrying member and the charge eliminating member, and an excessive potential difference between the toner carrying member with little or almost no toner and the charge removing member. It is also necessary to solve the problem that overcurrent flows, discharge phenomenon occurs, toner is deteriorated, and problems such as a charge removal member and a developer carrying member such as a developer carrying member cannot be prevented. .

Further, since the electric resistance of the static elimination member is as low as 10 ⁻⁵ to 10 ⁶ Ω, when the resistance value of the developer carrier and the toner is high, the potential difference between the static elimination member and the developer carrier should be set high. In addition, when there is almost no toner on the developer carrying member after development, the potential difference between the developer carrying member and the charge eliminating member may become excessively large. In the meantime, it is also necessary to solve the problem that it is impossible to prevent an overcurrent from flowing, a discharge phenomenon to occur, and the deterioration of the toner and the deterioration of the developing member such as the charge removal member and the developer carrying member.

  Furthermore, the potential difference between the excess charge-eliminating member and the developer carrying member increases the force that the weakly charged toner on the developer carrying member moves toward the charge removing member, and the weakly charged toner is held on the developer carrying member. Since the force is weak and easy to peel off, it also solves the problem of weakly charged toner adsorbing or accumulating and adhering to the nip portion or the vicinity of the neutralization member over time and accelerating the problem of damaging the developer carrier with the adhered toner mass It is a point to be done.

  Conversely, when the electrical resistance of the static elimination member, toner, and developer carrier is low, the potential difference between the static elimination member and the developer carrier is supposed to be small. There is a problem of not removing the toner. Therefore, it is also a point to be solved that due to the size of the triboelectric charging capability of the static elimination member, excessive static elimination or insufficient static elimination occurs and an appropriate static elimination effect cannot be obtained.

  Furthermore, since a potential difference is provided between the static elimination member and the developer carrying member, it is necessary to apply a potential to the static elimination member, so that an extra power source is required, and it is possible to solve the problem that the cost and size cannot be reduced. It is a point.

  Further, in the conventional developing method, it is assumed that the charge eliminating member is made of a material that is biased to the same polarity as the normal charge polarity of the toner in the charging series, and a potential difference is provided between the charge eliminating member and the developer carrying member. However, as described above, this alone does not take into account the triboelectric charging ability of the neutralizing member with the toner. Specifically, the neutralizing current value corresponding to the triboelectric charging capacity and the potential difference between the neutralizing member and the developer carrying member are set. Therefore, it is possible to prevent excessive charge removal, insufficient charge removal, an excessive potential difference between the charge removal member and the developer carrying member, and deterioration of various members such as the charge removal member and developer carrying member. This is another point that should be resolved.

  Further, for these problems, after the developer carrying member having the developer formed in a predetermined layer thickness performs black image development, the developer is supplied by the developer supply member, and the predetermined layer is again supplied by the developer layer regulating member. The average volume particle diameter of the developer carried by the developer carrying member when formed to be thick is Dbk, and the developer carrying member having a predetermined layer thickness is subjected to white image development. When the developer is supplied by the developer supply member and the average volume particle diameter of the developer carried by the developer carrier when the developer layer regulating member is formed to have a predetermined layer thickness again is defined as DWt, By satisfying DWt / Dbk> 0.8, the afterimage and ghost image of development can be eliminated. However, according to this method alone, particle size selection is always required for development and excessive Static elimination and static elimination member and developer Since the toner deteriorates over time due to discharge or the like due to the potential difference between the holders, the particle size of the developer (toner) and the charge amount distribution must be sharpened, and the toner manufacturing cost is high for classification and the like. In addition, even with the toner produced in this way, the contact-type non-magnetic one-component developing method puts considerable stress on the toner, and it is difficult to maintain the particle size and charge amount distribution over time sharply. In addition, there is a problem with durability.

  Furthermore, it is a point to be solved that there is no standard for preventing excessive static elimination and insufficient static elimination as described above.

  Further, in the developing device having the conventional static elimination member, there is no specific provision in the peripheral speed ratio SR ratio of the developer supply member with respect to the developer carrying member corresponding to the process speed. The developer carrier itself and the toner on the developer carrier are deteriorated, the toner remaining on the developer carrier after development is excessively scraped, or the developer carrier and the developer are rubbed too much. This is a problem to be solved. Therefore, a large amount of reverse polarity and weakly charged toner is produced, density unevenness due to uneven thickness of the toner layer on the developer carrier is generated, or these reverse polarity and weakly charged toner are in the eyes of the developer supply member. It also solves the problem that a large amount of toner enters the developer supply member by frictional heat to harden the developer supply member, and the developer supply member scrapes the developer carrier to generate black streaks. It is a point. In addition, after the charge removal, the toner on the developer carrier is excessively scraped off by the developer supply member, and after the toner is supplied from the developer supply member to the developer carrier, uncharged toner from the toner hopper is removed. In many cases, since the toner charge amount is low, the toner carrying force of the developer carrier itself becomes weak, so soft aggregates due to weakly charged, reverse polarity, uncharged toner, etc. or weakly charged, reverse polarity, uncharged toner, etc. It is also a point to be solved that the charging member is easily caught and white streaks are generated on the image. In addition, when the SR ratio is too large, there is developer scraping and excessive friction by the developer supply member. However, if the process speed is increased even if the SR ratio is constant, the rotation speed of the developer supply member increases, and the developer supply member The amount of the developer to be embraced decreases, resulting in a problem that the developer supply capability decreases and the solid followability deteriorates. On the contrary, if the SR ratio is too small, the developer supply described above is performed. The problem of black-and-white streaks due to the developer scraping by the member and excessive friction is eliminated, but the supply capability from the developer supply member to the development carrier is simply lowered, and the solid followability deteriorates. In addition, since the charge imparting ability is also reduced, the toner charge amount on the developer carrying member is reduced, and white streaks due to a decrease in toner conveying force are also to be solved.

  In view of the above problems, the present invention can reduce the size, reduce the price, extend the life of a developer member such as a developer carrier, and prevent development ghosts, afterimages, and solid follow-up deterioration, It is an object of the present invention to provide a developing device and an image forming method capable of preventing image defects such as black and white stripes and density unevenness due to excessive charge removal, excessive external additives, excessive developer supply member peripheral speed.

  The developing device of the present invention has a rotatable image carrier that carries an electrostatic latent image, and a rotatable, electrically conductive and semiconductive material that is disposed in contact with the image carrier and carries a one-component developer. A developer carrying member, a developing unit including a voltage applying unit to the developer carrying member, a developer supplying member that supplies the developer to the developer carrying member, a developer carrying member, and an image carrier. A charging unit that is disposed upstream of the developing position in contact with the developer carrying member in the rotation direction and has a charging member that charges the developer and regulates the thickness of the developer layer on the developer carrying body; Disposed on the downstream side in the rotation direction of the developer carrying member, and provided with a charge removing means having a charge removing member for discharging charges remaining on the developer carrying member after development at the developing position. The contact surface or the charge eliminating member itself is more charged than the developer. The developer (toner) is formed of a material that is biased toward the same polarity as the normal charging polarity, and a static elimination electric field of 150 V or less is formed between the developer carrying member and the static elimination member. With this configuration, since the triboelectric charging capability of the static elimination member itself can be secured, the static elimination current value (−5.0 μA or less) that causes deterioration of the toner or the developer member or the like can be eliminated. It is possible to obtain a developing device capable of preventing development ghosts and afterimages without increasing the potential difference between the member and the developer carrying member.

  Further, the static elimination member is electrically floated or at the same potential as the developer carrying member, and no static elimination electric field forming device or circuit element is connected between the developer carrying member and the static elimination member. With this configuration, it is possible to further remove the toner on the developer bearing member in consideration of the frictional power of the charge removal member, and without excessive charge removal current value (toner layer current value −5.0 μA or less). Development ghosts and afterimages can be prevented without taking the potential difference between the static elimination member and the developer carrying member or without passing the static elimination current to the static elimination member, and excessive static elimination current or static elimination current itself does not flow to the static elimination member. It is possible to prevent the overcurrent partially flowing between the static elimination member and the developer carrying member, the occurrence of a discharge phenomenon, the deterioration of the toner, and the development member such as the static elimination member and the developer carrying member. In which it is possible to obtain a developing unit to so that. Further, since the charge eliminating member is electrically floated or at the same potential as the developer carrying member, there is almost no potential difference between the charge removing member and the developer carrying member, and the weakly charged toner on the developer carrying member is directed toward the charge removing member. Since the moving force does not work, it is possible to obtain a developing device that can prevent a developer (toner) such as a weakly charged toner on the developer carrying member from adsorbing or staying and adhering to or near the nip portion of the static elimination member over time. It is possible. Therefore, the developer carrying member is not damaged by the toner fixed to or near the nip portion of the static elimination member. In addition, excessive charge removal can be prevented, and the occurrence of reverse polarity and weakly charged toner can be reduced, resulting in uneven density due to uneven toner layer thickness on the developer carrier, and the reverse polarity and weakly charged toner being supplied by the developer. It is possible to prevent the developer supply member from being scraped off by the developer supply member being hardened by entering a large amount into the eye of the member and hardening the developer supply member. Further, even after static elimination, since the toner on the developer carrier is not scraped off excessively by the developer supply member, uncharged toner is supplied from the toner hopper after the toner is supplied from the developer supply member to the developer carrier. However, there is a toner layer that maintains a certain amount of charge, the developer carrier itself has a strong toner conveying force, and is softly charged with weakly charged, reverse polarity, uncharged toner, etc. or weakly charged, reverse polarity, uncharged toner, etc. It is possible to obtain a developing device that can prevent the aggregates from being caught by the charging member and prevent white streaks from occurring on the image.

  Since the charge eliminating member is electrically floated or at the same potential as the developer carrying member, the surface contacting the developer carrying member or the charge removing member itself is more charged than the developer, and the normality of the developer (toner) If it is not formed with a material that is biased to the same polarity as the charged polarity of the toner, the ghost and afterimage due to development will deteriorate due to insufficient charge removal of the toner on the developer carrier after development, and there will be a potential difference between the charge removal member and the developer carrier. If this occurs, an excessive potential difference will occur and the charge removal current may be less than −5.0 μA. As described above, the ghost and the afterimage are improved due to the excessive charge removal of the toner on the developer carrier after development. Deterioration of the member and defects such as white streaks occur on the image. The charge eliminating member may also serve as a seal member for preventing toner leakage, and the seal member may be provided separately. As materials that are more charged than the toner in the charging series, the materials having the same polarity as the normal charging polarity of the toner include polytetrafluoroethylene (PTFE), tetrafluoroethylene, and polyvinylidene fluoride for negatively charged toner. Fluorine resins such as (PVDF) and tetrafluoroethylene / perfluoropropyl vinyl ether (PFA) can be exemplified, and polyamide (nylon) and silicon resin can be exemplified for positively charged toner. As materials for adjusting the resistance of these materials, examples of materials having good conductivity to be dispersed include carbon, various conductive metal particles, and other suitable charge control substances. This dispersion includes application of a charge control substance.

  Further, the static elimination member is a polyvinylidene fluoride (PVDF) or tetrafluoroethylene / perfluoropropyl vinyl ether (PFA) type resin having a particularly high charging ability among the fluororesins. Since the charging ability can be improved, it is possible to further reduce the excessive static elimination current value (-5.0μA or less) and the potential difference between the static elimination member and the developer carrying member, which cause degradation of the toner and the developer unit. Alternatively, it is possible to obtain a developing device which can be almost eliminated and can be compatible with the prevention of development ghosts and afterimages.

  Further, the external additive coverage of the developer (according to the following formula (1)) is 80 to 100%, more preferably 85 to 95%. Silica is mainly used as the external additive, but is not limited to silica. Fine inorganic powders such as colloidal silica, titanium oxide, and alumina, fine organic compounds such as fatty acids or derivatives thereof, and metal salts thereof are used. Powders (such as zinc stearate) and fluororesin fine powders may be used.

The external additive coverage C (%) is Ns / Nt for the ratio of the number of external additives (silica, etc.) to one developer (toner), Ss for the projected area of one external additive, and developer (toner) 1 If the surface area of each piece is St,
C (%) = Ns / Nt × Ss / St (calculation formula (1))

The number ratio of external additives (silica, etc.) to one developer (toner) is Ns / Nt. The weight Wt of one developer is multiplied by the additive additive%, and the weight of one external additive is 1 Ws. The projected area Ss of one external additive is obtained by π × (external additive radius) ² , and the surface area St of one developer is obtained by 4π × (developer radius) ² . Further, the external additive coverage of the entire developer is the sum of the external additive coverages for all types of external additives obtained by the calculation formula (1).

  With this configuration, it is possible to accurately improve the developer charging characteristics with external additives, improve image uniformity and solid followability by optimizing fluidity, and significantly reduce the amount of external additives (silica, etc.) that are detached, released or aggregated. Because it is weakly charged, reversely charged, or aggregated into large particles, it has a weak retention force on the developer carrier and is easy to peel off (especially aggregated silica etc.). Because there is almost no agglomerated silica or the like (external additive), even if there is no potential difference between the static elimination member and the developer carrier, weak charge is adsorbed or stuck to the nip portion or the vicinity of the static elimination member over time. Then, using the fixed portion as a nucleus, the toner is also fixed and grows into a toner lump, and a developing device is obtained in which the developer carrying member is hardly damaged and black stripes are hardly formed. Further, since there are almost no reverse poles and weakly charged particles (detached / free / aggregated silica, etc.), density unevenness due to uneven toner layer thickness on the developer carrier is generated, and these reverse poles and weakly charged particles ( A developer that releases a large amount of desorbed / free / aggregated silica into the eye of the developer supply member, hardens the developer supply member, and does not cause the developer supply member to scrape the developer carrier. Is what you get. Furthermore, since the transport force on the developer carrier is weak (especially those that are aggregated into large particles), there are no weakly charged / reversely charged / aggregated particles (detached / free / aggregated silica, etc.). Soft agglomerates due to the reverse pole, uncharged silica, etc. or weakly charged, reverse pole, uncharged silica, etc. get caught on the charging member, and the toner adheres and grows with the external additive such as silica stuck as a core, and the image is printed at that part. Thus, a developing device in which white streaks are hardly generated is obtained. In addition, it is possible to simultaneously obtain a developing device in which the charge ratio and fluidity of the toner are lowered and the image uniformity and the solid followability are not lowered by making the external additive coverage too small.

  Further, the developer charge amount Q / M on the developer carrying member neutralized by the charge eliminating member is 20 to 70% of the developer charge amount Q / M on the developer carrying member before the charge removing by the charge eliminating member. More preferably, it is 30 to 50%. Examples of means for this configuration include friction charging characteristics of the static elimination member, materials such as strength, resistance value, pressing conditions, and various conditions such as charging characteristics of toner, doctor blade, developer carrier, developer supply member, and the like. . With this configuration, it is possible to achieve a charge removal performance considering both the charge removal of the toner on the developer carrying member due to the frictional charge of the charge removal member and the current of the toner layer charge amount, and it is possible to improve the charge removal accuracy. In addition, it is possible to improve the accuracy of preventing image defects such as afterimages, and the charge removal performance for obtaining the minimum charge removal effect is obtained. Since current does not flow to the member itself, an overcurrent partially flows between the static elimination member and the developer carrier, a discharge phenomenon occurs, the toner is deteriorated, and the development of the static elimination member, developer carrier, etc. Thus, it is possible to obtain a developing device that can prevent deterioration of the container member. Further, it is possible to further improve the accuracy of preventing excessive static elimination and to reduce the occurrence of reverse polarity and weakly charged toner with high accuracy, resulting in uneven density due to uneven toner layer thickness on the developer carrier. To further prevent the opposite polarity and weakly charged toner from entering a large amount into the eyes of the developer supply member, hardening the developer supply member, and scraping the developer carrier. I can do it. Further, even after static elimination, since the toner on the developer carrier is not scraped off excessively by the developer supply member, uncharged toner is supplied from the toner hopper after the toner is supplied from the developer supply member to the developer carrier. However, there is a toner layer that retains a certain amount of charge, and the developer carrying body itself has a strong toner conveying force, and it is weakly charged, reverse polarity, uncharged toner, etc. It is possible to obtain a developing device that can prevent the aggregates from being caught by the charging member and further prevent the occurrence of white streaks on the image.

  Further, in the particle size distribution of the developer, when the developer volume average particle size is X, X × 1.4 to X × 1.82 ≦ 3.8%, X × 1.82 or more ≦ 0.36 % Developer having a particle size distribution (coarse powder cut toner), more preferably X × 1.4 to X × 1.82 ≦ 3%, X × 1.82 to ≦ 0.3%. In addition, the developer coarse powder is reduced. With this configuration, it is possible to reduce fluctuations in the particle size before and after development due to selection of the development particle size, so that it is possible to prevent fluctuations in the specific charge of the toner on the developer carrier, and to prevent development ghosts and afterimages, and particle size selection. As a result, it is possible to prevent the accumulation of coarse powder toner in the developing device due to the progress of the toner, so that the image quality deterioration due to the occurrence of density unevenness due to the unevenness of the toner layer thickness on the developer carrier, A large amount of toner enters the eye of the supply member, hardens the developer supply member, the developer supply member scrapes the developer carrier, or the coarsely charged toner itself or the reversely charged toner of the coarsely powdered toner, uncharged toner, A developing device is obtained in which soft agglomerates can be prevented from staying and adhering to or near the charging member portion or the neutralizing member nip portion to generate white streaks and scratches on the developer carrying member and black streaks. is there. In addition, by these structures, the developing device which can obtain the effect by the operation | movement by the structure in which the static elimination member mentioned above electrically set the same electric potential as the float or the developer carrying body can be obtained with higher accuracy is obtained.

  Also, the particle size distribution and the charge amount distribution of the developer are narrowed, and in particular, the CV value [%] representing the volume particle size distribution defined as CV = 100 × (standard deviation / average value) is within 25%. Yes, more preferably within 23%. With this configuration, the variation in particle size before and after development due to the selection of the development particle size can be reduced, so that the specific charge fluctuation of the toner on the developer carrier can be prevented, development ghosts and afterimages can be prevented, and the particle size selection can be made. Can prevent accumulation of fine powder, coarse powder, and deteriorated toner in the developing device due to the progress of the image quality. Therefore, image quality deterioration due to uneven density due to uneven toner layer thickness on the developer carrier, A large amount of toner enters the eye of the developer supply member, hardens the developer supply member, the developer supply member scrapes the developer carrier, or the reverse of these fine powder, coarse powder toner itself or fine powder, coarse powder toner. Charged, uncharged toner and soft aggregates can be prevented from staying and adhering to or near the nip of the charging member or neutralization member to prevent white streaks and scratches on the developer carrier and black streaks. Get the developer too It is. Furthermore, since fine powder and coarse powder cause toner fluidity to deteriorate extremely (in the case of fine powder) and extremely improve (in the case of coarse powder), optimal toner fluidity can be obtained by eliminating them. As a result, the toner charge amount distribution becomes sharper, and a developing device is obtained which leads to improvement in solid followability, development property and transferability. Note that the CV value of 25% or less improves the above-described accuracy of the effect even more than the coarse powder cutting of the developer (toner).

  Further, the pressing force between the developer carrying member and the charge eliminating member is set to a tensile load of 30 to 100 gf or less. With this configuration, the charge removing member is strongly applied to the developer carrying member, and the developer carrying member is developed on the developed developer carrying member. The charge of the remaining toner is excessively discharged to cause the above-mentioned problems, the toner layer on the developer carrying member cannot pass through the removing member, causing toner leakage, or the nip between the removing member and the developer carrying member. Heat is generated due to friction in the area, causing the toner to deteriorate, or the toner to be fused to the nip surface of the charge eliminating member or developer carrier, thereby damaging the developer carrier and causing images such as streaks and uneven density. If the pressing force of the static eliminator is weak, the potential difference between the static eliminator and the developer carrier is excessive in order to increase the static elimination effect unless a static eliminator with high frictional charging capability is used. Have to let Therefore, it is easy to discharge between the charge eliminating member and the developer carrying member, and it is possible to prevent the various members from being deteriorated, and to obtain a developing device capable of preventing the stable charge removal and the developer member deterioration. It is.

  Further, the peripheral speed ratio SR ratio between the developer carrier and the developer supply member is 47 / process speed ≦ SR ratio (counter) ≦ 58 / process speed. With this configuration, development according to the process speed is achieved. Since the peripheral speed ratio SR ratio of the developer supply member with respect to the developer carrying member can be set to an excessive SR ratio, the developer carrying member itself or the toner on the developer carrying member is deteriorated, or after development. Due to excessive scraping of the toner remaining on the developer carrying member or excessive friction between the developer carrying member and the developer, a large amount of reverse polarity and weakly charged toner is produced, and the toner layer thickness on the developer carrying member is uneven. Density unevenness occurs, these reverse polarity and weakly charged toner enter a large amount in the eyes of the developer supply member, or the developer on the developer supply member is melted by frictional heat to harden the developer supply member. , Its developer It can feed member to obtain a development device to prevent the occurrence of black muscle or cutting the developer carrying member. In addition, after the static elimination, in order to scrape off the toner on the developer carrier excessively by the developer supply member, after the toner is supplied from the developer supply member to the developer carrier, uncharged toner from the toner hopper In many cases, since the toner charge amount is low, the toner carrying force of the developer carrier itself becomes weak, so soft aggregates due to weakly charged, reverse polarity, uncharged toner, etc. or weakly charged, reverse polarity, uncharged toner, etc. It is possible to obtain a developing device that is easily caught by the charging member and can prevent white streaks from occurring on the image.

  Further, when the SR ratio is increased too much, in addition to the developer scraping and excessive friction caused by the developer supply member, and when the process speed is increased at a constant SR ratio, the rotation speed of the developer supply member is increased and the developer is increased. As a result, there is a problem that the developer supply ability is reduced and the solid followability is deteriorated, or the SR ratio is excessively reduced, and the developer supply member described above scrapes the developer. The problem of black-and-white streaks due to removal and excessive friction is eliminated, but the ability to supply the developer carrying member from the developer supply member to the developing carrier simply decreases, and the solid followability deteriorates. Solid followability deteriorates. In addition, it is possible to obtain a developing device capable of accurately preventing the occurrence of white streaks due to a decrease in toner conveying force due to a decrease in charge imparting ability and a decrease in toner charge amount on the developer carrying member.

  In addition, the image forming method of the present invention includes a rotatable image carrier that carries an electrostatic latent image, and a rotatable, conductive, semiconductive member that is disposed in contact with the image carrier and carries a one-component developer. In the developer carrying body having conductivity, a developing process for forming a toner image with a developer (toner) on the image carrying body by applying a voltage to the developer carrying body, and the developer carrying body and the image carrying body. A charging step of charging the developer and regulating the thickness of the developer layer on the developer carrier by applying a voltage to a charging member arranged upstream of the developing position in contact with the developer carrier in the rotation direction; A charge removing step for discharging charges remaining on the developer carrying member after development at the developing position by a charge removing member disposed downstream of the developing position in the developer carrying member rotation direction; The member may be a surface abutting against the developer carrying member or the static eliminating member Is formed of a material that is biased to the same polarity as the regular charging polarity of the developer (toner) in the charging series than the developer, and within 150 V between the developer carrying member and the charge eliminating member. With this configuration, it is possible to secure the triboelectric charging capability of the neutralization member itself, and therefore, an excessive neutralization current value (−5. The image forming method can prevent development ghosts and afterimages without increasing the potential difference between the charge eliminating member and the developer carrying member.

  In the static elimination step, the static elimination member is electrically floated or at the same potential as the developer carrying body, and a static elimination electric field forming device or a circuit element is connected between the developer carrying body and the static elimination member. With this configuration, the toner on the developer carrying member can be further discharged in consideration of the frictional band power of the discharging member, and an excessive discharging current value (toner layer current value −5. 0 μA or less), it is possible to prevent development ghosts and afterimages without taking the potential difference between the static elimination member and the developer carrying member, or without passing the static elimination current to the static elimination member, and excessive static elimination current or static elimination to the static elimination member. Since the current itself does not flow, an overcurrent partially flows between the static elimination member and the developer carrying member, a discharge phenomenon occurs, the toner deteriorates, or the developing device member such as the static elimination member or the developer carrying member. Image forming method capable of preventing the degradation in which can be obtained. Further, since the charge eliminating member is electrically floated or at the same potential as the developer carrying member, there is almost no potential difference between the charge removing member and the developer carrying member, and the weakly charged toner on the developer carrying member is more Therefore, an image forming method that can prevent a developer (toner) such as a weakly charged toner on the developer carrying member from adsorbing or staying and adhering to or near the nip portion of the static elimination member over time is obtained. It can be done. Therefore, the developer carrying member is not damaged by the toner fixed to or near the nip portion of the static elimination member. In addition, excessive charge removal can be prevented, and the occurrence of reverse polarity and weakly charged toner can be reduced, resulting in uneven density due to uneven toner layer thickness on the developer carrier, and the reverse polarity and weakly charged toner being supplied by the developer. It is possible to prevent the developer supply member from being scraped off by the developer supply member being hardened by entering a large amount into the eye of the member and hardening the developer supply member. Further, even after static elimination, since the toner on the developer carrier is not scraped off excessively by the developer supply member, uncharged toner is supplied from the toner hopper after the toner is supplied from the developer supply member to the developer carrier. However, there is a toner layer that retains a certain amount of charge, and the developer carrying body itself has a strong toner conveying force, and it is weakly charged, reverse polarity, uncharged toner, etc. or weakly charged, reverse polarity, uncharged toner, etc. It is possible to obtain an image forming method capable of preventing the aggregates from being caught on the charging member and preventing white streaks from being generated on the image.

  Since the charge removal member is electrically floated at the same potential as the developer carrying member, the surface contacting the developer carrying member or the charge removing member itself is more charged than the developer, and the developer (toner) normal If it is not made of a material that is biased to the same polarity as the charged polarity, the ghost and afterimage due to development will deteriorate due to insufficient charge removal of the toner on the developer carrier after development, and a potential difference will be created between the charge removal member and the developer carrier. In some cases, an excessive potential difference occurs and the charge removal current is less than −5.0 μA. As described above, the ghost and the afterimage are improved due to the excessive charge removal of the toner on the developer carrying member, but the developer member. Deterioration and defects such as white streaks occur on the image. The neutralizing member may also serve as a seal member for preventing toner leakage, or may be provided separately. As a material that is more charged than the toner in the charging series, the material is shifted to the same polarity as the normal charging polarity of the toner. For negatively charged toners, polytetrafluoroethylene (PTFE), tetrafluoroethylene, polyvinylidene fluoride Fluorine resins such as (PVDF), tetrafluoroethylene / perfluoropropyl vinyl ether (PFA) can be exemplified, and polyamide (nylon) and silicon-based resin can be exemplified for positively charged toner. As materials for adjusting the resistance of these materials, examples of materials having good conductivity to be dispersed include carbon, various conductive metal particles, and other suitable charge control substances. This dispersion includes application of a charge control substance.

  Further, the static elimination member in the static elimination step is a polyvinylidene fluoride (PVDF) or a tetrafluoroethylene / perfluoropropyl vinyl ether (PFA) type resin having a particularly high charging ability among the fluorine series resins. Can further improve the charging ability of the static elimination member, and therefore, an excessive static elimination current value (−5.0 μA or less) that causes deterioration of the toner, the developer member, etc., and the static elimination member and the developer carrying member. It is possible to obtain an image forming method in which the potential difference can be further reduced or almost eliminated and both development ghost and afterimage can be prevented.

  In the development step, the external additive coverage of the developer (according to the following calculation formula (1)) is 80 to 100%, more preferably 85 to 95%. Silica is mainly used as the external additive, but is not limited to silica. Fine inorganic powders such as colloidal silica, titanium oxide, and alumina, fine organic compounds such as fatty acids or derivatives thereof, and metal salts thereof are used. Powders (such as zinc stearate) and fluororesin fine powders may be used.

The external additive coverage C (%) is Ns / Nt for the ratio of the number of external additives (silica, etc.) to one developer (toner), Ss for the projected area of one external additive, and developer (toner) 1 If the surface area of each piece is St,
C (%) = Ns / Nt × Ss / St (calculation formula (1))

The number ratio of external additives (silica, etc.) to one developer (toner) is Ns / Nt. The weight Ws of one external additive is obtained by multiplying the weight Wt of one developer by the additive additive%. The projected area Ss of one external additive is obtained by π × (external additive radius) ² , and the surface area St of one developer is obtained by 4π × (developer radius) ² . Further, the external additive coverage of the entire developer is the sum of the external additive coverages for all types of external additives obtained by the calculation formula (1).

  With this configuration, it is possible to accurately improve the developer charging characteristics with external additives, improve image uniformity and solid followability by optimizing fluidity, and drastically reduce external additives (silica, etc.) that are detached, liberated, and agglomerated. Because it is weakly charged, reversely charged, or aggregated into large particles, it has a weak retention force on the developer carrier and is easy to peel off (especially aggregated silica etc.). Because there is almost no agglomerated silica or the like (external additive), even if there is no potential difference between the static elimination member and the developer carrier, weak charge is adsorbed or stuck to the static elimination member nip or its vicinity over time. Then, using the fixed portion as a nucleus, the toner is also fixed and grows into a toner lump, and an image forming method is obtained in which the developer carrying member is hardly damaged and black lines are hardly formed. Further, since there are almost no reverse poles and weakly charged particles (detached / free / aggregated silica, etc.), density unevenness due to uneven toner layer thickness on the developer carrier is generated, and these reverse poles and weakly charged particles ( Image formation in which a large amount of desorbed / free / aggregated silica or the like) enters the eye of the developer supply member, hardens the developer supply member, and the developer supply member does not scrape the developer carrier. Get the method. Furthermore, since the transport force on the developer carrier is weak (especially those that are aggregated into large particles), there are no weakly charged / reversely charged / aggregated particles (detached / free / aggregated silica, etc.). Soft agglomerates due to reverse polarity, uncharged silica, etc. or weakly charged, reverse polarity, uncharged silica, etc. get caught on the charging member, and the toner adheres and grows using the external additive such as silica as the core, and the image is printed An image forming method in which white streaks are hardly generated on the surface is obtained.

  In addition, it is possible to simultaneously obtain an image forming method in which the external additive coverage is reduced too much, whereby the charging characteristics and fluidity of the toner are lowered, and the image uniformity and the solid followability are not lowered.

  Further, in the charge eliminating and charging step, the developer charge amount Q / M on the developer carrying member that has been discharged by the charge removing member is equal to the developer charge amount Q / M on the developer carrying member before the charge removal by the charge removing member. It is said that it is 20-70%, More preferably, it is 30-50%. Examples of means for this configuration include friction charging characteristics of the static elimination member, materials such as strength, resistance value, pressing conditions, and various conditions such as charging characteristics of toner, doctor blade, developer carrier, developer supply member, and the like. . With this configuration, it is possible to achieve a charge removal performance that takes into account both the charge removal of the toner on the developer carrying member due to frictional charge of the charge removal member and the current of the toner layer charge amount, and it is possible to improve the charge removal accuracy. In addition, it is possible to improve the accuracy of preventing image defects such as afterimages, and the charge removal performance for obtaining the minimum charge removal effect, the excess charge current value exceeding the toner layer current value (−5 μA or less) or the charge removal member itself. Since no current flows to the discharge member, an overcurrent partially flows between the charge removal member and the developer carrying member, a discharge phenomenon occurs, the toner deteriorates, or the developer member such as the charge removing member or the developer carrying member. It is possible to obtain an image forming method that can prevent the deterioration of the image quality. Further, it is possible to further improve the accuracy of preventing excessive static elimination and to reduce the occurrence of reverse polarity and weakly charged toner with high accuracy, resulting in uneven density due to uneven toner layer thickness on the developer carrier. To further prevent the opposite polarity and weakly charged toner from entering a large amount into the eyes of the developer supply member, hardening the developer supply member, and scraping the developer carrier. I can do it. Further, even after static elimination, since the toner on the developer carrier is not scraped off excessively by the developer supply member, uncharged toner is supplied from the toner hopper after the toner is supplied from the developer supply member to the developer carrier. However, there is a toner layer that maintains a certain amount of charge, the developer carrier itself has a strong toner conveying force, and is softly charged with weakly charged, reverse polarity, uncharged toner, etc. or weakly charged, reverse polarity, uncharged toner, etc. It is possible to obtain an image forming method capable of preventing the aggregate from being caught by the charging member and further preventing the occurrence of white streaks on the image.

  Further, in the development step, when the developer volume average particle size is X in the particle size distribution of the developer, X × 1.4 to X × 1.82 ≦ 3.8%, X × 1.82 or more The developer (coarse powder cut toner) having a particle size distribution satisfying ≦ 0.36%, more preferably X × 1.4 to X × 1.82 ≦ 3%, X × 1.82 or more ≦ 0.3 % Developer (coarse powder cut toner) having a particle size distribution of%. With this configuration, it is possible to reduce fluctuations in the particle size before and after development due to selection of the development particle size, so that it is possible to prevent fluctuations in the specific charge of the toner on the developer carrier, and to prevent development ghosts and afterimages, and particle size selection. As a result, it is possible to prevent the accumulation of coarse powder toner in the developing device due to the progress of the toner, so that the image quality deterioration due to the occurrence of density unevenness due to the unevenness of the toner layer thickness on the developer carrier, A large amount of toner enters the eye of the supply member, hardens the developer supply member, the developer supply member scrapes the developer carrier, or the coarsely charged toner itself or the reversely charged toner of the coarsely powdered toner, uncharged toner, An image forming method capable of preventing the occurrence of white streaks caused by soft agglomerates staying and adhering to or near the nip part of the charging member or the neutralizing member, and the generation of black streaks due to scratches on the developer carrier. It is. In addition, with these configurations, an image forming method can be obtained in which the operation by the configuration in which the charge eliminating member described above is electrically at the same potential as that of the float or the developer carrying member can obtain a more accurate operation effect. .

  Also, in the development process, the developer particle size distribution and the charge amount distribution are narrowed. In particular, the CV value [%] representing the volume particle size distribution defined as CV = 100 × (standard deviation / average value) is within 25%. Is used, and is more preferably within 23%. With this configuration, it is possible to reduce fluctuations in the particle size before and after development due to selection of the development particle size, so that it is possible to prevent fluctuations in the specific charge of the toner on the developer carrier, and to prevent development ghosts and afterimages, and particle size selection. Can prevent the accumulation of fine powder, coarse powder and deteriorated toner in the developing device due to the progress of the toner image quality deterioration due to density unevenness due to uneven toner layer thickness on the developer carrier, their reverse polarity and weak charging A large amount of toner enters the eye of the developer supply member, hardens the developer supply member, and the developer supply member scrapes the developer carrier, or the fine powder, coarse powder toner itself or fine powder, coarse powder toner It is possible to prevent reverse charging, uncharged toner and soft agglomerates from staying and adhering to or near the nip portion of the charging member or the neutralizing member and causing white streaks and scratches on the developer carrier to cause black streaks. Image shape The method is intended to obtain. Furthermore, since fine powder and coarse powder cause toner fluidity to deteriorate extremely (in the case of fine powder) and extremely improve (in the case of coarse powder), optimal toner fluidity can be obtained by eliminating them. As a result, the toner charge amount distribution becomes sharp, and an image forming method that leads to improvement in solid followability, development property, and transfer property is obtained. The CV value [%] within 25% is to improve the above-described effect accuracy more than the coarse powder cut.

  Further, in the static elimination step, the pressing force between the developer carrying member and the static elimination member is set to a tensile load of 30 to 100 gf or less. With this configuration, the static elimination member is strongly applied to the developer carrier and development after development is performed. The charge remaining on the carrier is excessively neutralized to cause the above-described problems, the toner layer on the developer carrier cannot pass through the static elimination member, and toner leakage occurs, or the static elimination member and the developer Heat generated by friction is generated at the nip portion of the carrier, causing the toner to deteriorate or fusing the toner to the nip surface of the static eliminator or developer carrier, thereby damaging the developer carrier, causing streaks and density In order to prevent image failure such as unevenness and the pressing force of the neutralizing member is weak, unless the neutralizing member with high frictional charging capability is used, in order to enhance the neutralizing effect, the excessive amount between the neutralizing member and the developer carrier Potential difference Therefore, discharge is likely to occur between the static elimination member and the developer carrying member, and it is possible to prevent the various members from being deteriorated, and to stably prevent the static elimination and the deterioration of the developer member. To get the method.

  In the development, static elimination, and charging steps, the peripheral speed ratio SR ratio between the developer carrier and the developer supply member is 47 / process speed ≦ SR ratio (counter) ≦ 58 / process speed. According to the configuration, the peripheral speed ratio SR ratio of the developer supply member to the developer carrier according to the process speed can be set, so that the excessive SR ratio becomes too high, and the developer carrier itself or the developer carrier Deteriorating the toner, excessively scraping off the toner remaining on the development carrier after development, or excessively rubbing the developer carrier and the developer to produce a large amount of reverse polarity and weakly charged toner. Density unevenness due to uneven toner layer thickness on the carrier, a large amount of the opposite polarity and weakly charged toner enter the eye of the developer supply member, or the developer on the developer supply member is caused by frictional heat. Melt Firmer image agent supplying member, the developer supplying member can be obtained an image forming method for preventing the occurrence of black muscle or cutting the developer carrying member. In addition, after the charge is removed in the charge eliminating step, the toner on the developer carrying member is excessively scraped off by the developer supplying member, and after the toner is supplied from the developer supplying member to the developer carrying member, Since there is a lot of uncharged toner and the toner charge amount is low, the toner carrying force of the developer carrier itself becomes weak, so weakly charged, reversed polarity, uncharged toner, etc., weakly charged, reversed polarity, uncharged toner, etc. It is possible to obtain an image forming method in which soft agglomerates are easily caught on the charging member and white streaks are prevented from being generated on the image.

  Furthermore, when the SR ratio is increased too much, in addition to the developer scraping and excessive friction caused by the developer supply member, the rotation speed of the developer supply member is increased when the process speed is increased at a constant SR ratio. As a result, there is a problem that the developer supply ability is reduced and the solid followability is deteriorated, or the SR ratio is excessively reduced, and the developer supply member described above scrapes the developer. The problem of black-and-white streaks due to removal and excessive friction is eliminated. It is possible to obtain an image forming method in which the amount of toner charge on the body is reduced and white streaks due to a decrease in toner conveying force are prevented with high accuracy.

  The present invention relates to a rotatable image carrier that carries an electrostatic latent image, and a rotatable and conductive and semiconductive developer that is disposed in contact with the image carrier and carries a one-component developer. Development means including a carrier and a voltage application means to the developer carrier, a developer supply member for supplying the developer to the developer carrier, and development in which the developer carrier and the image carrier are in contact with each other A charging means having a charging member disposed upstream of the position in the developer carrying member rotation direction to charge the developer and regulate the thickness of the developer layer on the developer carrying body; and the developer carrying from the development position A discharge member disposed on the downstream side of the body rotation direction for discharging charges remaining on the developer carrying member after development at the developing position, the surface contacting the developer carrying member or the charge removing member; The member itself is more charged than the developer, and the developer (toner) is positive. Is formed of a material that is biased toward the same polarity as the charging polarity of the toner, and a static elimination electric field within 150 V is formed between the developer carrying member and the static elimination member. Since the charging ability can be secured, the potential difference between the charge eliminating member and the developer carrying member can be increased without an excessive charge removal current value (−5.0 μA or less) that causes deterioration of the toner and the developer member. Even if it is not necessary, an effect of preventing development ghosts and afterimages can be obtained.

  In addition, the above-described static elimination member is electrically floated or the same potential as the developer carrying member, and no static elimination electric field forming device or circuit element is connected between the developer and the static elimination member. Further, since the toner on the developer carrying member can be neutralized in consideration of the frictional power of the static elimination member, the static elimination member and the development can be performed without an excessive static elimination current value (toner layer current value −5.0 μA or less). Development ghosts and afterimages can be prevented without taking the potential difference of the agent-carrying member or supplying the discharging member to the discharging member, and excessive discharging current or discharging current itself does not flow to the discharging member. It is possible to prevent an overcurrent or a discharge phenomenon from occurring between the developer carrying members, causing the toner to deteriorate, and preventing the developing member such as the charge eliminating member and the developer carrying member from being deteriorated. It is intended to be. Further, since the static elimination member is electrically floated or at the same potential as the developer carrying member, and no static elimination electric field forming device or circuit element is connected between the developer and the static elimination member, the static elimination member and the developer There is almost no potential difference between the carriers, and the weakly charged toner on the developer carrier does not act to move toward the charge eliminating member, so that the developer (toner) such as the weakly charged toner on the developer carrier is aged over time. Therefore, it is possible to prevent the adsorbing member or the adhering deposit from adhering to or near the nip portion of the static elimination member. Therefore, the developer carrying member is not damaged by the toner fixed to or near the nip portion of the static elimination member. In addition, excessive charge removal can be prevented, and the occurrence of reverse polarity and weakly charged toner can be reduced, resulting in uneven density due to uneven toner layer thickness on the developer carrier, and the reverse polarity and weakly charged toner being supplied by the developer. There is an effect that the developer supply member is hardened by entering a large amount into the eye of the member, and the developer supply member can be prevented from scraping the developer carrier. Further, even after static elimination, since the toner on the developer carrier is not scraped off excessively by the developer supply member, uncharged toner is supplied from the toner hopper after the toner is supplied from the developer supply member to the developer carrier. However, there is a toner layer that maintains a certain amount of charge, and the developer carrying body itself has a strong toner conveying force, and softly charged, reversely charged, uncharged toner, etc. or weakly charged, reversely charged, uncharged toner, etc. It is possible to prevent the aggregates from being caught on the charging member and to prevent white streaks from being generated on the image. In addition, by electrically floating the static elimination member, there is no need for a power source, a Zener diode, a grounding resistor, etc. to supply the static elimination electric field such as voltage and potential to the static elimination member, and the cost can be greatly reduced and the size can be reduced. Have

  In addition, the static elimination member is made of polyvinylidene fluoride (PVDF) or tetrafluoroethylene / perfluoropropyl vinyl ether (PFA) type resin, which has a particularly high charging ability among the fluororesins. Since the capability can be improved, it is possible to further reduce the excessive static elimination current value (−5.0 μA or less) and the potential difference between the static elimination member and the developer carrying member, which cause deterioration of the toner and the developer member. It is possible to eliminate almost all of them, and an effect compatible with the prevention of development ghosts and afterimages can be obtained.

  Further, the external additive coverage of the developer (according to the following formula (1)) is 80 to 100%, more preferably 85 to 95%. As a result, it is possible to accurately improve the developer charging characteristics by external additives, improve image uniformity and solid followability by optimizing fluidity, and drastically reduce external additives (silica, etc.) that are detached, liberated and aggregated. Therefore, it is weakly charged, reversely charged, or aggregated into large particles, and it has a weak retention force on the developer carrier and is easy to peel off (particularly aggregated silica, etc.). Silica and the like (external additive) are almost eliminated, so that even if there is no potential difference between the static elimination member and the developer carrier, the weak charge is adsorbed or accumulated and stuck to the nip portion or the vicinity of the static elimination member over time. With the fixed portion as a nucleus, the toner is also fixed and grows into a toner lump, and the developer carrying member is hardly damaged and black streaks are almost eliminated. Further, since there are almost no reverse poles and weakly charged particles (detached / free / aggregated silica, etc.), density unevenness due to uneven toner layer thickness on the developer carrier is generated, and these reverse poles and weakly charged particles ( A developer that releases a large amount of desorbed / free / aggregated silica into the eye of the developer supply member, hardens the developer supply member, and does not cause the developer supply member to scrape the developer carrier. Is what you get. Furthermore, since the transport force on the developer carrier is weak (especially those that are aggregated into large particles), there are no weakly charged / reversely charged / aggregated particles (detached / free / aggregated silica, etc.). Soft agglomerates due to the reverse pole, uncharged silica, etc. or weakly charged, reverse pole, uncharged silica, etc. get caught on the charging member, and the toner adheres and grows with the external additive such as silica stuck as a core, and the image is printed at that part. It is possible to obtain an effect that almost no white stripes are generated. Further, if the external additive coverage is made too small, the charging characteristics and fluidity of the toner are lowered, and the image uniformity and the solid followability are not lowered.

  Further, the developer charge amount Q / M on the developer carrying member neutralized by the charge eliminating member is 20 to 70% of the developer charge amount Q / M on the developer carrying member before the charge removing by the charge eliminating member. More preferably, it is 30 to 50%. As a result, it is possible to achieve a charge removal performance considering both the charge removal of the toner on the developer carrying member due to the frictional charge of the charge removal member and the current of the toner layer charge amount, and it is possible to improve the charge removal accuracy. Since it is possible to improve the accuracy of preventing image defects such as afterimages, and to achieve a charge removal performance for obtaining the minimum charge removal effect, an excessive charge removal current value greater than the toner layer current value (−5.0 μA or less) or a charge removal member Since current does not flow to itself, an overcurrent partially flows between the charge-removing member and the developer-carrying member, a discharge phenomenon occurs, the toner is deteriorated, or a developing device such as a charge-removing member or developer-carrying member. The effect which can prevent deteriorating a member is acquired. Further, it is possible to further improve the accuracy of preventing excessive static elimination and to reduce the occurrence of reverse polarity and weakly charged toner with high accuracy, resulting in uneven density due to uneven toner layer thickness on the developer carrier. To further prevent the opposite polarity and weakly charged toner from entering a large amount into the eyes of the developer supply member, hardening the developer supply member, and scraping the developer carrier. I can do it. Further, even after static elimination, since the toner on the developer carrier is not scraped off excessively by the developer supply member, uncharged toner is supplied from the toner hopper after the toner is supplied from the developer supply member to the developer carrier. However, there is a toner layer that retains a certain amount of charge, and the developer carrying body itself has a strong toner conveying force, and it is weakly charged, reverse polarity, uncharged toner, etc. or weakly charged, reverse polarity, uncharged toner, etc. It is possible to prevent the aggregates from being caught by the charging member, and to obtain the effect of further preventing the occurrence of white streaks on the image.

  Further, in the particle size distribution of the developer, when the developer volume average particle size is X, X × 1.4 to X × 1.82 ≦ 3.8%, X × 1.82 or more ≦ 0.36 % Of the developer (coarse powder cut toner) having a particle size distribution, more preferably X × 1.4 to X × 1.82 ≦ 3%, and X × 1.82 or more ≦ 0.3%. This distribution of the developer (coarse powder cut toner) can reduce fluctuations in the particle size before and after development due to selection of the development particle size, thereby preventing fluctuations in the specific charge of the toner on the developer carrier. , Development ghosts, afterimages can be prevented, and accumulation of coarse powder toner in the developing device due to the progress of particle size selection can be prevented, so image quality can be caused by uneven density due to uneven toner layer thickness on the developer carrier. Deterioration, their reverse polarity and weakly charged toner enter a large amount in the eyes of the developer supply member. The developer supply member is hardened, and the developer supply member scrapes the developer carrier, or the coarse powder toner itself or the reverse charge of the coarse powder toner, the uncharged toner, and the soft agglomerate are charged member portions or static elimination. It is possible to prevent the occurrence of white streaks and scratches on the developer carrying member due to staying and fixing at or near the member nip and the occurrence of black streaks. With these configurations, it is possible to obtain a more accurate operation effect due to the configuration in which the static elimination member described above is electrically at the same potential as the float or developer carrier.

  Also, the particle size distribution and the charge amount distribution of the developer are narrowed, and in particular, the CV value [%] representing the volume particle size distribution defined as CV = 100 × (standard deviation / average value) is within 25%. Yes, more preferably within 23%. As a result, the particle size variation before and after the development due to the selection of the particle size of the development can be reduced, so that the specific charge variation of the toner on the developer carrier can be prevented, development ghost and afterimage can be prevented, and the particle size can be selected. Accumulation of fine powder, coarse powder, and deteriorated toner in the developing device due to progress can be prevented, so image quality deterioration due to density unevenness due to uneven toner layer thickness on the developer carrying member, these reverse polarity and weakly charged toner are developer A large amount of toner enters the eye of the supply member, hardens the developer supply member, the developer supply member scrapes the developer carrier, or reverse charging of these fine powder, coarse powder toner itself or fine powder, coarse powder toner, Uncharged toner and soft agglomerates can prevent white streaks due to staying and fixing at or near the nip of the charging member or neutralization member, and the effect of preventing black streaks from scratching the developer carrier. It is. Furthermore, since fine powder and coarse powder cause toner fluidity to deteriorate extremely (in the case of fine powder) and extremely improve (in the case of coarse powder), optimal toner fluidity can be obtained by eliminating them. As a result, the toner charge amount distribution becomes sharper, and the effect of improving solid followability, developing property, and transfer property is obtained.

  Further, the pressing force between the developer carrying member and the charge eliminating member is set to a tensile load of 30 to 100 gf or less. With this configuration, the charge removing member is strongly applied to the developer carrying member, and the developer carrying member is developed on the developed developer carrying member. The remaining toner charge is excessively neutralized to cause the above-mentioned problems, the toner layer on the developer carrier cannot pass through the static elimination member, and the toner leaks, or the nip between the static elimination member and the developer carrier. Heat is generated due to friction at the edges, causing the toner to deteriorate, or the toner to be fused to the nip surface of the charge removal member or developer carrier, thereby damaging the developer carrier and causing images such as streaks and uneven density. It has the effect of preventing obstacles. In addition, when the pressing force of the static elimination member is weak, unless a static elimination member having a high frictional charging capability is used, in order to enhance the static elimination effect, an excessive potential difference must be provided between the static elimination member and the developer carrier. For this reason, the discharge is likely to occur between the static elimination member and the developer carrying member, and it is possible to prevent the various members from being deteriorated, thereby obtaining the effect of preventing the static elimination and the deterioration of the developer member.

  Further, the peripheral speed ratio SR ratio between the developer carrier and the developer supply member is 47 / process speed ≦ SR ratio (counter) ≦ 58 / process speed, whereby the developer corresponding to the process speed is obtained. Since the peripheral speed ratio SR ratio of the developer supply member with respect to the carrier can be set to an excessive SR ratio, the developer carrier itself or the toner on the developer carrier is deteriorated, or development after development. Concentration due to uneven toner layer thickness on the developer carrier by creating excessive amounts of negative and weakly charged toner by excessively scraping off the toner remaining on the carrier or excessively rubbing the developer carrier and developer. Unevenness occurs, or these negative and weakly charged toners enter a large amount in the eyes of the developer supply member, or the developer supply member is melted by frictional heat to harden the developer supply member, The developer supply Wood is intended to obtain the effect of preventing the occurrence of black muscle or cutting the developer carrying member. In addition, after the charge removal, the toner on the developer carrying member is excessively scraped off by the developer supplying member. In many cases, since the toner charge amount is low, the toner carrying force of the developer carrier itself becomes weak, so soft aggregates due to weakly charged, reverse polarity, uncharged toner, etc. It is easy to get caught by the charging member, and the effect of preventing white streaks from occurring on the image is obtained.

  Furthermore, when the SR ratio is increased too much, in addition to the developer scraping and excessive friction caused by the developer supply member, the rotation speed of the developer supply member is increased when the process speed is increased at a constant SR ratio. As a result, there is a problem that the developer supply ability is lowered and the solid followability is deteriorated. The problem of black and white streaks due to removal and excessive friction is eliminated. The toner charge amount on the body is reduced, and the effect of accurately preventing the occurrence of white streaks due to a reduction in toner conveying force is obtained.

  According to the first and tenth aspects of the present invention, a rotatable image carrier that carries an electrostatic latent image, and a rotatable image carrier that is disposed in contact with the image carrier and carries a one-component developer. Developing means including a developer carrier having conductivity and semiconductivity, and means for applying a voltage to the developer carrier, a developer supply member for supplying the developer to the developer carrier, and a developer carrier A charging member disposed upstream of the developing position where the image carrier and the image carrier are in contact with each other in the rotation direction of the developer carrier to charge the developer and to regulate the thickness of the developer layer on the developer carrier And a discharging means having a discharging member disposed downstream of the developing position in the rotation direction of the developer carrying member and discharging charges of the developer remaining on the developer carrying member after development at the developing position. A surface that contacts the developer carrying member or the charge eliminating member itself It is made of a material that is more biased than the developer in the same charging polarity as the regular charging polarity of the developer (toner), and a static elimination electric field of 150 V or less is formed between the developer carrying member and the static elimination member. Because the triboelectric charging ability of the static elimination member itself can be secured, an excessive static elimination current value (−5.0 μA or less) that causes deterioration of the toner or the developer member or the like can be obtained. It has the effect of preventing development ghosts and afterimages without increasing the potential difference between the charge eliminating member and the developer carrying member.

  The invention described in claims 2 and 11 is the invention described in claims 1 and 10, wherein the charge eliminating member is electrically floated or at the same potential as the developer carrying member, and the developer carrying member and the charge removing member are Since no static elimination electric field forming device or circuit element is connected between them, the toner on the developer carrying member can be further eliminated in consideration of the frictional band power of the static elimination member. Prevents image defects such as development ghosts and afterimages without taking the potential difference between the static elimination member and the developer carrier, or without passing the static elimination current to the static elimination member, even if the excessive static elimination current value (−5 μA or less) is not exceeded. In addition, since the excessive static elimination current or the static elimination current itself does not flow to the static elimination member, the overcurrent partially flows between the static elimination member and the developer carrying member, or a discharge phenomenon occurs, resulting in poor toner. Or it is, those having an effect of being able to prevent the degradation of the charge removing member and the developer carrying member such as a developing device member. In addition, since the static elimination member is electrically at the same potential as the float or developer carrier, and no static elimination electric field forming device or circuit element is connected between the developer and the static elimination member, the static elimination member and the developer carrier are not connected. There is almost no potential difference, and the weakly charged toner on the developer carrying member does not have a force to move toward the static eliminator, so the developer (toner) such as the weakly charged toner on the developer carrying member is removed over time. It has an action that can prevent adhering or adhering to the part or the vicinity. Therefore, the developer carrying member is not damaged by the toner fixed to or near the nip portion of the static elimination member. In addition, excessive static elimination can be prevented, and the occurrence of reverse polarity and weakly charged toner can be reduced. Further, even after static elimination, the toner on the developer carrying member is not scraped off excessively by the developer supply member, so that the conveying force of the toner on the developer carrying member can be secured.

  The charge eliminating member may also serve as a seal member for preventing toner leakage, and the seal member may be provided separately. As a material that is more charged than the toner in the charging series, the material is shifted to the same polarity as the normal charging polarity of the toner. For negatively charged toners, polytetrafluoroethylene (PTFE), tetrafluoroethylene, polyvinylidene fluoride Fluorine resins such as (PVDF), tetrafluoroethylene / perfluoropropyl vinyl ether (PFA) can be exemplified, and polyamide (nylon) and silicon-based resin can be exemplified for positively charged toner. As materials for adjusting the resistance of these materials, examples of materials having good conductivity to be dispersed include carbon, various conductive metal particles, and other suitable charge control substances. This dispersion includes application of a charge control substance.

  The inventions described in claims 3 and 12 are the inventions described in claims 1-2 and 10-11, wherein the charge-removing member is polyvinylidene fluoride (PVDF) or tetrafluoroethylene having particularly high charging ability among fluororesins.・ Perfluoropropyl vinyl ether (PFA) -based resin, which can further improve the chargeability of the charge removal member, resulting in excessive charge removal current that causes deterioration of the toner and developer members, etc. The value (−5.0 μA or less) and the potential difference between the charge eliminating member and the developer carrying member can be further reduced or almost eliminated, and have an effect compatible with the prevention of development ghost and afterimage.

The invention described in claims 4 and 13 is the invention described in claims 1 to 3 and 10 to 12, wherein the external additive coverage of the developer (according to the following formula (1)) is 80 to 100%. More preferably, it is 85 to 95%. The external additive coverage C (%) is Ns / Nt for the ratio of the number of external additives (silica, etc.) to one developer (toner), Ss for the projected area of one external additive, and developer (toner) 1 If the surface area of each piece is St,
C (%) = Ns / Nt × Ss / St (calculation formula (1))

The number ratio of external additives (silica, etc.) to one developer (toner) is Ns / Nt. The weight Ws of one external additive is obtained by multiplying the weight Wt of one developer by the additive additive%. The projected area Ss of one external additive is obtained by π × (external additive radius) ² , and the surface area St of one developer is obtained by 4π × (developer radius) ² . Further, the external additive coverage of the entire developer is the sum of the external additive coverages for all types of external additives obtained by the calculation formula (1). As a result, it is possible to accurately improve the developer charging characteristics by external additives, improve image uniformity and solid followability by optimizing fluidity, and drastically reduce external additives (silica, etc.) that are detached, liberated and aggregated. Therefore, it is weakly charged, reversely charged, or aggregated into large particles, and it has a weak retention force on the developer carrier and is easy to peel off (particularly aggregated silica, etc.). Silica and the like (external additive) are almost eliminated, so that even if there is no potential difference between the static elimination member and the developer carrier, the weak charge is adsorbed or accumulated and stuck to the nip portion or the vicinity of the static elimination member over time. The toner also adheres and grows into a toner lump using the fixed portion as a nucleus, and has an effect of preventing the developer carrier from being damaged. Further, since there are almost no reverse poles and weakly charged particles (detached / free / aggregated silica, etc.), density unevenness due to uneven toner layer thickness on the developer carrier is generated, and these reverse poles and weakly charged particles ( (Desorbed / free / aggregated silica, etc.) penetrates a large amount into the eye of the developer supply member, hardens the developer supply member, and prevents the developer supply member from scraping the developer carrier. Have. Furthermore, since the transport force on the developer carrier is weak (especially those that are aggregated into large particles), there are no weakly charged / reversely charged / aggregated particles (detached / free / aggregated silica, etc.). Soft agglomerates due to the reverse pole, uncharged silica, etc. or weakly charged, reverse pole, uncharged silica, etc. get caught on the charging member, and the toner adheres and grows with the external additive such as silica stuck as a core, and the image is printed at that part. It has the effect of almost eliminating the occurrence of white streaks. In addition, it is possible to simultaneously obtain the effect of reducing the external additive coverage ratio so that the charging characteristics and fluidity of the toner are lowered, and the image uniformity and the solid followability are not lowered.

  The invention described in claim 5 and 1.4 is the invention described in claims 1-4 and 10-13, wherein the developer charge amount Q / M on the developer carrying member that has been neutralized by the neutralizing member is equal to the neutralizing member. That is, the developer charge amount Q / M on the developer carrying member before the charge removal by is 20 to 70%, more preferably 30 to 50%. Examples of means for this configuration include friction charging characteristics of the static elimination member, materials such as strength, resistance value, pressing conditions, and various conditions such as charging characteristics of toner, doctor blade, developer carrier, developer supply member, and the like. . As a result, it is possible to achieve a charge removal performance considering both the charge removal of the toner on the developer carrying member due to the frictional charge of the charge removal member and the current of the toner layer charge amount, and it is possible to improve the charge removal accuracy. Since it is possible to improve the accuracy of preventing image defects such as afterimages, and to achieve a charge removal performance for obtaining the minimum charge removal effect, an excessive charge removal current value or charge removal member exceeding the toner layer current value (−5.0 μA or less). Since current does not flow to itself, an overcurrent partially flows between the static elimination member and the developer carrying member, a discharge phenomenon occurs, the toner deteriorates, or the developing device such as the static elimination member or the developer carrying member. It has the effect | action which can prevent deteriorating a member. Further, it is possible to further improve the accuracy of preventing excessive static elimination and to reduce the occurrence of reverse polarity and weakly charged toner with high accuracy, resulting in uneven density due to uneven toner layer thickness on the developer carrier. To further prevent the opposite polarity and weakly charged toner from entering a large amount into the eyes of the developer supply member, hardening the developer supply member, and scraping the developer carrier. Has the effect of Further, even after static elimination, since the toner on the developer carrier is not scraped off excessively by the developer supply member, uncharged toner is supplied from the toner hopper after the toner is supplied from the developer supply member to the developer carrier. However, there is a toner layer that maintains a certain amount of charge, the developer carrier itself has a strong toner conveying force, and is softly charged with weakly charged, reverse polarity, uncharged toner, etc. or weakly charged, reverse polarity, uncharged toner, etc. It has an effect of preventing the aggregate from being caught by the charging member and further preventing the occurrence of white streaks on the image.

  The inventions of claims 6 and 15 are the inventions of claims 1 to 5 and 10 to 14, in which X × 1. The developer (coarse powder cut toner) having a particle size distribution of 4 to X × 1.82 ≦ 3.8%, X × 1.82 or more and ≦ 0.36%, and more preferably X × 1.4 to The developer (coarse powder cut toner) having a particle size distribution satisfying X × 1.82 ≦ 3% and X × 1.82 or more ≦ 0.3%. Since the variation in diameter can be reduced, the specific charge fluctuation of the toner on the developer carrier can be prevented, development ghost and afterimage can be prevented, and the accumulation of coarse powder toner in the developing device due to the progress of the particle size selection can be prevented. As a result, uneven density due to uneven toner layer thickness on the developer carrier may occur. Deterioration in quality, these opposite polarities, and weakly charged toner enter a large amount in the eyes of the developer supply member, harden the developer supply member, the developer supply member scrapes the developer carrier, The toner itself or coarsely charged toner is reversely charged, uncharged toner, and soft agglomerates stay and adhere to the charging member or neutralizing member nip or in the vicinity to generate white streaks, scratches on the developer carrier, and black streaks. It has the effect | action which can prevent doing. In addition, by these structures, the effect | action by the structure by which the static elimination member mentioned above electrically set the same electric potential as the float or the developer carrying body obtains a more accurate operation effect.

  The invention described in claims 7 and 16 narrows the particle size distribution and charge amount distribution of the developer in the inventions described in claims 1 to 6 and 10 to 15, particularly CV = 100 × (standard deviation / average value). The CV value [%] representing the volume particle size distribution defined as is within 25%, more preferably within 23%. As a result, the particle size variation before and after the development due to the selection of the particle size of the development can be reduced, so that the specific charge variation of the toner on the developer carrier can be prevented, development ghost and afterimage can be prevented, and Accumulation of fine powder, coarse powder, and deteriorated toner in the developing device due to progress can be prevented, so image quality deterioration due to occurrence of density unevenness due to uneven toner layer thickness on the developer carrier, development of these negative and weakly charged toners The developer supply member hardens the developer supply member, and the developer supply member scrapes off the developer carrier, or reverse charging of the fine powder, coarse powder toner itself or fine powder, coarse powder toner. In addition, the non-charged toner and soft agglomerates have an action capable of preventing white streaks from being accumulated and stuck in or near the charging member portion or the neutralizing member nip portion, and the streaks of the developer carrying member to cause black streaks. Furthermore, since fine powder and coarse powder cause toner fluidity to deteriorate extremely (in the case of fine powder) and extremely improve (in the case of coarse powder), optimal toner fluidity can be obtained by eliminating them. As a result, the toner charge amount distribution becomes sharp, and has the effect of improving solid followability, developing property, and transfer property. Note that setting the CV value to 25% or less has an effect of improving the above-described effect accuracy more than the coarse powder cut.

  The invention according to claims 8 and 17 is the invention according to claims 1 to 7 and 10 to 16, wherein the pressing force of the developer carrying member and the charge eliminating member is set to a tensile load of 30 to 100 gf or less. If the charge-removing member is applied too strongly to the developer carrier, the charge remaining on the developer carrier after development is excessively discharged, causing the above-mentioned problems, or the toner layer on the developer-carrying member is neutralized. Cannot pass through the member, causing toner leakage, heat generated by friction at the nip between the static elimination member and the developer carrying member, degrading the toner, or toner on the nip surface of the static elimination member or developer carrying member By fusing it, the developer carrying member is damaged, and image defects such as streaks and density unevenness are prevented. In addition, when the pressing force of the static elimination member is weak, unless a static elimination member having a high frictional charging capability is used, in order to enhance the static elimination effect, an excessive potential difference must be provided between the static elimination member and the developer carrier. Therefore, the discharge is likely to occur between the static elimination member and the developer carrying member, and it is possible to prevent the various members from being deteriorated, and to have a function of preventing the static elimination and the deterioration of the developer member.

  The invention described in claims 9 and 18 is the invention described in claims 1-8 and 10-17, wherein the peripheral speed ratio SR ratio between the developer carrier and the developer supply member is 47 / process speed ≦ SR ratio ( Counter) ≦ 58 / process speed, and this makes it possible to obtain a peripheral speed ratio SR ratio of the developer supply member to the developer carrier in accordance with the process speed, resulting in an excessive SR ratio. The developer carrier itself and the toner on the developer carrier are deteriorated, the toner remaining on the developer carrier after development is excessively scraped, or the developer carrier and the developer are rubbed too much, Create a large amount of reverse polarity and weakly charged toner to cause density unevenness due to uneven toner layer thickness on the developer carrier, or a large amount of these reverse polarity and weakly charged toner enter the eyes of the developer supply member. Dripping, frictional heat Firmer developer supplying member by dissolving more developer supplying member on the developer, the action of the developer supplying member is prevented from generating a black muscle or cutting the developer carrying member is obtained. In addition, after the charge removal, the toner on the developer carrier is excessively scraped off by the developer supply member, and after the toner is supplied from the developer supply member to the developer carrier, uncharged toner from the toner hopper is removed. In many cases, since the toner charge amount is low, the toner carrying force of the developer carrier itself is weakened, so soft aggregates due to weakly charged, reverse polarity, uncharged toner, etc. It is easily caught by the charging member and has an effect of preventing white streaks from occurring on the image.

  Further, when the SR ratio is increased too much, in addition to the developer scraping and excessive friction caused by the developer supply member, and when the process speed is increased at a constant SR ratio, the rotation speed of the developer supply member is increased and the developer is increased. As a result, there is a problem that the developer supply capability is lowered and the solid followability is deteriorated, or the SR ratio is excessively reduced, and the developer supply member scrapes the developer. The problem of black-and-white streaks due to lowering of charging, lowering of charging ability and excessive friction is eliminated, but the supply ability from the developer supply member to the development carrier is reduced, and the solid followability deteriorates. As a result, the toner charge amount on the developer carrying member decreases, and the white streaks due to the decrease in the toner conveying force are prevented with high accuracy.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is a diagram showing a developing device according to an embodiment of the present invention. (A) is a diagram in which the static elimination member is electrically floated, and (b) is a diagram in the case where the static elimination member is electrically at the same potential as the developer carrying member. FIG. 2 is a schematic diagram illustrating detailed steps of development, charge removal, developer supply, and charging (thinning) unit in the developing device according to the embodiment of the present invention. (A) is a diagram in which the static elimination member is electrically floated, and (b) is a diagram in the case where the static elimination member is electrically at the same potential as the developer carrying member. FIG. 3 is a diagram showing a developing device according to an embodiment of the present invention. FIG. 6 is an explanatory diagram showing a scraping effect of a developer (toner) on a developer carrying member by a developer supply member. FIG. 4 is a graph showing the toner charging characteristics (toner fluidity) with respect to the toner external additive coverage and the electric field between developer carriers (including the case where there is no electric field) over time in the developing device according to the embodiment of the present invention. FIG. 5 is an explanatory diagram showing how toner (silica or the like) adheres to a neutralizing member nip, and how toner (silica or the like) adheres to a charging member nip. FIG. 5 is an explanatory diagram showing the effect of scraping off the developer (toner) on the developer carrying member by the developer supply member with respect to the charge amount after charge removal and the charge removal effect in the developing device according to the embodiment of the present invention. FIG. 6 shows a developing device according to an embodiment of the present invention. In the developing device, the static elimination member is electrically floated or at the same potential as the developer carrying member, and the static elimination electric field forming device or between the developer carrying member and the static elimination member It is explanatory drawing which shows the effect at the time of making it the thing which a circuit element is not connected. FIG. 7 is an explanatory diagram showing the effect when the toner external additive coverage is 80 to 100% (more preferably 85 to 95%) in the developing device according to the embodiment of the present invention. FIG. 8 is an explanatory diagram showing an effect when toner obtained by cutting coarse powder is used in the developing device according to the embodiment of the present invention. FIG. 9 is a schematic diagram illustrating a method for measuring the pressing force between the charge removal member and the developer carrying member in the developing device according to the embodiment of the present invention. FIG. 10 is a diagram showing an image pattern for evaluating the development ghost. FIG. 11 is a schematic diagram illustrating the overall structure of an image forming apparatus including a developing device according to an embodiment of the present invention. The following description will be given along these drawings. Here, the same number is attached | subjected about the structure same as a prior art, and description is abbreviate | omitted.

  First, a schematic configuration of the image forming apparatus will be described with reference to FIG. The image carrier 1 is a photosensitive drum that carries an electrostatic latent image, in which a photosensitive layer is provided on a metal drum. As the photoreceptor layer, an OPC layer, an a-SiH layer, a selenium layer, or the like is used. In addition, a conductive undercoat layer may be provided between the aluminum base tube and the CGL so that scratches and dirt on the base tube do not affect the charging characteristics of the photoreceptor. In the case of the OPC layer, it is composed of a relatively thin carrier generating layer (CGL) formed on the undercoat layer and a relatively thin carrier moving layer (CTL) mainly composed of polycarbonate formed on the outermost layer. . By exposure, carriers are generated in the carrier generation layer, and the charges charged on the image carrier 1 are canceled by the carriers to form an electrostatic latent image. In addition, you may use what made this mixed layer of CGL and CTL into a single layer. The image carrier 1 is rotationally driven at a constant speed in the direction of the arrow during an image forming operation, and various image forming process means are disposed so as to face the periphery of the image carrier 1.

  Reference numeral 23 denotes a charging device that is disposed with a predetermined gap from the surface of the image carrier 1 and charges the image carrier 1. Although a charging roller charging device is shown in FIG. 11, a non-contact charging device such as a scorotron, a corotron charging device or a solid charging element may be used, and a charging brush may also be used. . In the present embodiment, description will be made using a charging roller charging device.

  An optical system 24 forms an electrostatic latent image by irradiating the surface of the charged image carrier 1 with light. Semiconductor laser light, LED light, CRT light, EL light, or the like may be used as an exposure source as long as the image carrier 1 (photosensitive member) emits light having a high absorption spectrum. If the image forming apparatus is a copying machine, the copy original is irradiated with light, and the reflected light from the original is irradiated as a light image. If the image forming apparatus is a printer or a digital copying machine, the optical system emits a light image obtained by driving a semiconductor laser on and off according to image data. In particular, in a digital copying machine, image data obtained by reading reflected light from a copy original with an image reading sensor (CCD element or the like) is input to the optical system including the semiconductor laser, and an optical image corresponding to the image data is output. Like to do. In the printer, the light image is converted into an image corresponding to the image data from another processing device such as a word processor or a personal computer, and this is irradiated.

  A developing device 8 according to the present invention for visualizing an electrostatic latent image formed on the surface of the image carrier 1 by being exposed by the optical system. Details will be described later.

  Reference numeral 25 denotes a transfer device as transfer means. As a transfer device, a transfer roller with a conductive urethane, EPDM, silicon or other sponge layer wrapped around a core, a transfer brush made of conductive fibers such as nylon or rayon, the tip of a conductive rubber plate or conductive film sheet A transfer blade or transfer film in contact with each other, a conductive belt in which a conductive material is dispersed in a resin material such as PTFE, PFA, TEP, polyimide, or polycarbonate are used. The transfer in the present invention is exemplified by the direct transfer method in which the image is directly transferred to the image receiving paper. However, the transfer is not limited. Alternatively, a non-contact type such as a scorotron or a corotron may be used as an intermediate transfer method or a transfer film which is transferred to image receiving paper in a lump (secondary or higher transfer).

  A registration roller 31 conveys the image receiving paper at a predetermined speed. Reference numeral 29 denotes image receiving paper such as plain paper, postcard paper, and OHP sheet. Reference numeral 32 denotes upstream guide means for guiding the conveyance direction of the image receiving paper 29 from the registration roller 31 to the image carrier 1. A fixing device 28 fixes the toner image transferred onto the image receiving paper 29. Reference numeral 33 denotes a downstream guide unit that guides the conveying direction of the image receiving paper from the transfer region to the fixing device 28. Note that, in an environment of high humidity, the image receiving paper 29 has a low resistance, and current leaks from the flexible member of the transfer device 25 to the guiding unit 3233 via the image receiving paper 29. For this reason, sufficient charge is not supplied to the back surface of the image receiving paper 29, and a transfer defect occurs. In order to solve this problem, it is preferable that the guide unit 3233 is formed of an insulating member or a voltage having the same polarity as the transfer voltage is applied. Further, a self-biasing element such as a resistance element or a Zener diode element may be connected between the guiding means 3233 and the ground.

  The fixing device 28 fixes an unfixed toner image transferred onto a sheet as a permanent image, and a heat roller whose surface facing the toner image is heated to a temperature at which the toner is melted and fixed. And a pressure roller or the like that is pressed against the heat roller to bring the image receiving paper 29 into close contact with the heat roller. The image receiving paper 29 that has passed through the fixing device 28 is discharged out of the image forming apparatus onto a discharge tray (not shown) via a discharge roller (not shown). In FIG. 11, the heating unit and the pressurizing unit show roller shapes, but the present invention is not limited to this, and a film-like or belt-like heating unit, a pressurizing unit, or the like may be used.

  A cleaning device 26 removes residual developer (toner) that has not been transferred to the surface of the image carrier 1 after transfer.

  Reference numeral 27 denotes a static eliminator that removes charged charges remaining on the surface of the image carrier 1 after transfer.

  The image receiving paper 29 is accommodated in a large amount, for example, in a tray or a cassette. The image receiving paper 29 accommodated in the image receiving sheet 29 is fed by a registration roller 31 and the image carrier 1 on which the transfer device 25 is disposed. The toner is fed to the opposing transfer area so as to coincide with the leading edge of the toner image formed on the surface of the image carrier 1. The image receiving paper 29 after the transfer is peeled off from the image carrier 1 and sent to the fixing device 28.

  Next, an outline of the operation of the image forming apparatus having the above configuration will be described.

  When the image forming operation in the image forming apparatus is started, the image carrier 1 is rotationally driven in the direction of the arrow, and the charger 23 uniformly charges the surface of the image carrier 1 to a specific polarity potential. When the charged surface of the image carrier 1 is transported to a position facing the exposure system 24, the surface of the image carrier 1 is irradiated with light according to the received image signal. As a result, the charged potential of the surface of the image carrier 1 in the region irradiated with light decreases. As a result, an electrostatic latent image is formed on the surface of the image carrier 1. Next, when the electrostatic latent image on the surface of the image carrier 1 is conveyed to a position facing the developing device 8, the toner on the developer carrier 2 to which a predetermined voltage is applied becomes the electrostatic latent image and the development. It moves onto the image carrier 1 according to the potential difference from the agent carrier 2. As a result, the toner adheres to the electrostatic latent image on the image carrier 1 and a toner image is formed on the image carrier 1. This operation is called development. In the present invention, this development is performed with a one-component developer, and the toner is selectively attracted to the electrostatic latent image formed on the surface of the image carrier 1 by, for example, electrostatic force, and development is performed.

  The toner image formed on the surface of the image carrier 1 is conveyed to a transfer area where the transfer device 25 and the image carrier 1 are in contact with each other. At this time, a voltage having a polarity opposite to that of the toner particles is applied to the transfer device 25. On the other hand, the rotation of the registration roller 31 is started, and the conveyance of the image receiving paper 29 held between the registration rollers 31 is started in synchronization with the conveyance of the toner image to the transfer region. The image receiving paper 29 conveyed along the upstream guide means 32 enters the transfer area. While passing through the transfer area, an electric field E is formed between the image receiving paper and the photosensitive drum by the electric charge accumulated on the back surface of the image receiving paper from the transfer device. As a result, the toner charge q and the Coulomb force F = qE by the electric field E act, and the toner on the image carrier 1 is transferred to the image receiving paper 29 side. Toner that is not charged with a normal polarity or toner with excessive mechanical adhesion is not attracted to the image receiving paper by the Coulomb force F, and remains on the surface of the image carrier 1 as transfer residual toner.

  After the transfer, a part of the toner image that has not been transferred remains on the surface of the image carrier 1, and this residual toner is removed from the surface of the image carrier 1 by the cleaning device 26 to reuse the image carrier 1. For this purpose, the surface of the image carrier 1 is neutralized by the static elimination device 27 to a uniform potential, for example, approximately zero potential. In the present invention, the image forming apparatus using the static elimination device 27 is illustrated, but the static elimination device 27 is not necessarily required and may be omitted or an alternative may be used.

  On the other hand, the transferred image receiving paper 29 is peeled off from the image carrier 1 and conveyed to the fixing device 28. In the fixing device 28, the toner image on the image receiving paper 29 is melted and pressed and fused to the image receiving paper 29 by the pressure applied between the rollers. The image receiving paper 29 passing through the fixing device 28 is discharged as an image-formed image receiving paper 29 to a discharge tray (not shown) provided outside the image forming apparatus.

  Next, the configuration of the developing device 8 that performs development with the one-component developer of the present invention will be described with reference to FIGS. The developing device 8 is rotatable in a developer (toner) hopper 34 containing a one-component developer, for example, a non-magnetic one-component developer (toner) 7, and attaches toner to the image carrier 1 to form a toner image. A developer carrier 2 that performs so-called development, and a developer supply member 3 that supplies the one-component developer 7 to the developer carrier 2 side are provided. An agitator or a screw roller 4 for feeding the component developer 7 to the vicinity of the developer supply member 3 is provided.

  The developer carrier 2 provided in the developing device 8 is partially exposed (development region 30 side), and the image carrier is used to convey the toner to the development region 30 facing the image carrier 1 described above. 1 is provided so as to be rotated in the same direction in the developing region 30 facing the first. The developer supply member 3 described above is pressed against the developer carrier 2. Further, a discharging member 5 for discharging / removing toner on the developer carrying member remaining after development is provided downstream of the developing region 30 in the rotation direction of the developer carrying member 2.

  The developer carrier 2 has a structure in which, for example, the surface of a conductive shaft (including a rotating shaft) is covered with a polymer elastic body, and the outer diameter is, for example, φ10-40. The conductive shaft is a metal such as stainless steel or a resin having a relatively low electric resistance value. As the polymer elastic body, a resin material having a relative dielectric constant of about 10 is used, and polyurethane, EPDM, silicon, nitrile butadiene rubber, chloroprene rubber, styrene butadiene rubber, butadiene rubber and the like can be used. Further, as a regulator of the electric resistance value of the polymer elastic body, an ion conductive material such as carbon black, titanium oxide, inorganic ion conductive material such as sodium perchlorate, calcium perchlorate, sodium chloride, etc. A surfactant of dialkylsiloxane or polysiloxane-polyalkylene oxide block copolymer can be used, and any one or more of these can be used. When a foaming agent is used for forming the elastic body, a silicon-based surfactant is optimal. Alternatively, if an ion conductive solid rubber or the like is used, a predetermined resistance value that does not cause toner fusion or the like can be maintained, and this effectively acts when a developing bias voltage is supplied as described later. The electric resistance value of the developer carrier 2 is E3 to E7Ω, preferably E5 to 6. The hardness of ISK-6301 (Asker C hardness meter load 1 kgf) is 60 to 70, and the surface roughness Rz of JISB0601 is about 1 to 6 μm. The hardness of the elastic member can be adjusted by the amount of vulcanizing agent or filler added.

  The developer carrier 2 is connected to a drive motor (not shown), and the developer carrier 2 is rotationally driven in the direction of the arrow in the figure. The one-component non-magnetic toner 7 is adsorbed on the surface of the rotating developer carrier 2 and conveyed to the developing area 30 facing the surface of the image carrier 1. Since the developer carrier 2 is pressed against the surface of the image carrier 1, the pressed area becomes a development region 30, and the one-component developer 7 is attracted to the electrostatic latent image on the surface of the photoreceptor 1. And developed. The developer carrying member 2 is supplied with a developing bias voltage Vb from a developing bias power supply circuit 9. The developing bias voltage Vb has a polarity and a voltage value such that the toner adheres to the electrostatic latent image formed on the image carrier 1 and toner does not adhere to other regions, that is, non-image regions. The voltage may be set to about 400 V, and AC may be applied to improve gradation and uniformity, prevent banding, increase the development amount, and the like.

  The developer 7 is a one-component non-magnetic toner having an average particle diameter of about 5 to 12 μm, for example, and a polyester toner or a styrene acrylic toner is used.

  The toner particles are composed of a binder resin in which a colorant is dispersed, regardless of whether the two-component developing device or the one-component developing device. The binder resin material is polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer. , Polyethylene, polypropylene and the like. Furthermore, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax and the like are used. In addition, as colorants, carbon black, nigrosine, aniline blue, calcoil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal, C. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment Yellow 180 can be listed. In addition to the above components, the toner of the present invention can contain a charge control agent, wax, and the like as necessary. Further, for the purpose of improving the durability, fluidity or cleaning properties of the toner, fine inorganic powders such as silica, colloidal silica, titanium oxide and alumina, fine organic compounds such as fatty acids or derivatives thereof and metal salts thereof (stearin). Zinc acid etc.), fluororesin fine powder and the like are preferably added as appropriate.

In the present invention, the external additive coverage of the developer (according to the following formula (1)) is 80 to 100%, more preferably 85 to 95%. The external additive coverage C (%) is Ns / Nt for the ratio of the number of external additives (silica, etc.) to one developer (toner), Ss for the projected area of one external additive, and developer (toner) 1 If the surface area of each piece is St,
C (%) = Ns / Nt × Ss / St (calculation formula (1))

The number ratio of external additives (silica, etc.) to one developer (toner) is Ns / Nt. The weight Ws of one external additive is obtained by multiplying the weight Wt of one developer by the additive additive%. The projected area Ss of one external additive is obtained by π × (external additive radius) ² , and the surface area St of one developer is obtained by 4π × (developer radius) ² . Further, the external additive coverage of the entire developer is the sum of the external additive coverages for all types of external additives obtained by the calculation formula (1). When this external additive coverage exceeds 100%, the number of external additives (silica, etc.) that desorb, liberate, and agglomerate significantly increases, and these external additives are weakly charged or reversely charged. Or agglomerated and large particles, the retention force on the developer carrier is weak and easy to peel (especially agglomerated silica, etc.), desorbed, free, agglomerated silica, etc. (external additive), Whether or not there is a potential difference between the static elimination member and the developer carrying member, the weak charge is adsorbed or accumulated and adhered to the nip portion or the vicinity of the static elimination member over time, and the toner adheres using the adhered portion as a nucleus. It grows into a toner lump and damages the developer carrier to become black streaks, or soft aggregates due to weakly charged, reverse polarity, uncharged silica, etc. or weakly charged, reverse polarity, uncharged silica, etc. are charged members. The toner adheres with the external additive such as silica as the core. And, white muscle is generated on the image at that portion. In addition, density unevenness due to uneven toner layer thickness on the developer carrier is generated, and a large amount of these reverse poles and weakly charged particles (detached / free / aggregated silica, etc.) are present in the eyes of the developer supply member. The developer supply member is hardened, and the developer supply member scrapes the developer carrier.

  On the other hand, when the external additive coverage is less than 80%, the charging characteristics and fluidity of the toner are lowered, and the image uniformity and the solid followability are lowered. As will be described later, the external additive coverage of the developer (according to the following formula (1)) is 80 to 100%, and more preferably 85 to 95%, the above-mentioned problem is solved. it can.

  In the present invention, in the particle size distribution of the developer (toner), when the average particle diameter of the toner is X, X × 1.4 to X × 1.82 ≦ 3.8%, X × 1.82 or more ≦ The developer (coarse powder cut toner) having a particle size distribution of 0.36%, more preferably X × 1.4 to X × 1.82 ≦ 3%, X × 1.82 or more ≦ 0.3% That is, the developer having the particle size distribution (coarse powder cut toner). If this X × 1.4 to X × 1.82 exceeds 3.8%, or X × 1.82 or more exceeds 0.36%, the variation in particle size before and after development due to the selection of the particle size of development is large. As a result, the specific charge fluctuation of the toner on the developer carrying member becomes large, so that a development ghost and an afterimage are generated. In addition, since the coarse powder toner in the developing device accumulates as the particle size selection progresses, the image quality deteriorates due to uneven density due to uneven toner layer thickness on the developer carrier, The weakly charged toner enters a large amount into the eyes of the developer supply member, hardens the developer supply member, and the developer supply member scrapes the developer carrier, or the coarse powder toner itself or the reverse of the coarse powder toner. Charged, uncharged toner, and soft agglomerates stay and adhere to the charging member portion or the neutralizing member nip portion or in the vicinity thereof to generate white stripes, or scratches on the developer carrying member to generate black stripes. As will be described later, the problem described above can be solved if X × 1.4 to X × 1.82 ≦ 3.8% and X × 1.82 or more ≦≦ 0.36%.

  In the present invention, the index CV value indicating the sharpness of the volume particle size distribution of the toner is preferably 25% or less. More preferably, it is within 23%. This CV value is expressed by 100 × (standard deviation of particle size / average value of particle size). The larger the volume particle size distribution is, the smaller the volume particle size distribution is.

  When this CV value exceeds 25%, the volume particle size distribution fluctuation of the toner on the developer carrying member becomes large and development ghost and afterimage are likely to occur. In the developer hopper, the developer supply member is weakly charged, the reverse polarity toner is clogged, clogged in the layer regulating member, stays in the charge removal member, etc. Deterioration of members such as scratches, particle size distribution and charge amount distribution become broad, charging characteristics and fluidity are deteriorated, and development characteristics such as solid followability and transferability are deteriorated. However, when a toner having a small CV value is used, the ratio of the small toner and the large toner to the volume average particle diameter is reduced, so that the fluctuation of the volume average particle diameter is also reduced, and the ratio of the toner on the developer carrier is reduced. The fluctuation of the charge amount is reduced, the development ghost and the afterimage are not generated, and the above-described member deterioration can be prevented. Furthermore, since fine powder and coarse powder cause toner flowability to be extremely deteriorated (in the case of fine powder) or extremely improved (in the case of coarse powder), by eliminating them (by reducing the CV value). ), Optimal toner fluidity can be obtained, and the toner charge amount distribution becomes sharp, and solid follow-up performance, development performance, and transfer performance can be improved.

  In the present invention, the charge amount of the toner is preferably −10 to −35 μC / g (10 to 30 μC / g in the case of positive charging). More preferably, it is −15 to −30 μC / g (15 to 30 μC / g in the case of positive charging). If the charge amount exceeds the above range, the charge amount of the toner is too large, the development amount is extremely reduced, the transfer electric field corresponding to the toner charge is insufficient, the transfer residual toner is extremely increased, Repel each other and cause splattering in transcription. If the ratio is lower than the above range, the ratio of the weakly charged toner in the developer hopper increases, the clogging of the weakly charged toner into the developer supply member, and the conveyance force of the toner on the developer carrying member become weak. Causes problems such as increased toner soft agglomerates, weakly charged, reverse polarity, uncharged toner, etc. The fixed toner damages the developer carrier and causes black streaks, excessive transfer electric field in the developer transfer process, Paschen discharge before and after the transfer nip, and charge injection in the transfer nip, As a result, the toner is easily charged to the reverse polarity, and the transfer residual toner is extremely increased or reverse transfer is caused.

The developer supply member 3 is rotationally driven so that the rotation direction is opposite to the rotation direction of the developer carrier 2 at a portion (pressure contact region) facing the developer carrier 2. The developer supply member 3 uses the same material as that of the developer carrier 2, and the electrical resistance can be adjusted with the same resistance adjustment material as that of the developer carrier 2. In order to further increase the elasticity of the developer supply member 3, a foamed (porous) material is used. Specifically, a conductive polyurethane foam having a volume resistivity of about 10 ⁴ to ⁶ ΩCm and a number of cells by foaming of about 3 to 4 / mm is formed of stainless steel or conductive resin on the shaft. With respect to the developer supply member 3, for example, the diameter is 10 to 40 mm, and the peripheral speed ratio with respect to the developer carrier is set between approximately 0.4 and 20.

  In the present invention, the peripheral speed ratio SR ratio of the developer supply member 3 with respect to the developer carrier 2 is 47 / process speed ≦ SR ratio (counter) ≦ 58 / process speed. Thereby, the peripheral speed ratio SR ratio of the developer supply member 3 to the developer carrier 2 corresponding to the process speed can be achieved. When this SR ratio exceeds 58 / process speed, the developer carrier 2 itself and the toner on the developer carrier 2 are deteriorated, or the toner remaining on the development carrier 2 after development is excessively scraped off. The developer carrier 2 and the developer 7 are rubbed too much to produce a large amount of reverse polarity and weakly charged toner, causing density unevenness due to uneven toner layer thickness on the developer carrier 2, The weakly charged toner enters a large amount into the eyes of the developer supply member 3, or the developer 7 on the developer supply member 3 is melted by frictional heat to harden the developer supply member 3, and the developer supply member 3 The developer carrying member 2 is scraped to generate black streaks. In addition, after the charge is removed, the toner 7 is supplied from the developer supply member 3 to the developer carrier 2 in order to scrape off the toner on the developer carrier 2 by the developer supply member 3 excessively. Since there is a large amount of uncharged toner and the charge amount of the toner is low, the toner carrying force of the developer carrier 2 itself is weakened. Therefore, weakly charged, reverse polarity, uncharged toner, etc., weakly charged, reverse polarity, uncharged toner The soft agglomerates due to the above are easily caught on the charging member 6 and white streaks are generated on the image. Furthermore, when the SR ratio is increased too much, in addition to the developer scraping and excessive friction by the developer supply member 3, the rotation speed of the developer supply member 3 is increased when the process speed is increased at a constant SR ratio. As a result, the amount of developer 7 embraced decreases, resulting in a decrease in developer supply capability and poor solid followability. On the contrary, when the SR ratio is smaller than 47 / process speed, the problem of black and white streaks due to the developer scraping by the developer supplying member 3 and excessive friction is eliminated. The supply capacity to the battery is reduced, and the solid followability deteriorates. Further, the charge imparting ability is also lowered, so that the toner charge amount on the developer carrying member is lowered and white streaks are generated due to a decrease in toner conveying force. As will be described later, if the peripheral speed ratio SR ratio between the developer carrier and the developer supply member is 47 / process speed ≦ SR ratio (counter) ≦ 58 / process speed, the above-described problem can be solved.

  AC may be applied to the shaft at a voltage Vs of about −150 to −600 V, for example, by increasing the toner supply power. The developer supply member 3 is brought into contact with the developer carrier 2 with a contact depth of 0.5 mm to 1 mm. The toner 7 is precharged, for example, negatively by the developer supply member 3.

  A bias voltage Vs is applied to the developer supply member 3 from the bias power supply circuit 11, and generally the direction in which the toner is pushed toward the developer carrier 2, that is, the toner on the developer supply member 3 side is repelled. The bias voltage in the direction to be supplied to the developer carrier 2 is set. For example, when negative toner is used, a larger bias voltage Vs is applied to the developer supply member 3 on the negative polarity side.

  The developer carrier 2 and the developer supply member 3 are connected to a drive motor (not shown). When the developer carrier 2 and the developer supply member 3 are driven to rotate in the direction of the arrow in the drawing, the developer supply member 3 supplies toner to the developer carrier 2. At the same time, the toner on the surface of the developer carrier 2 that has not contributed to the development after development is peeled off (removed). The toner supplied by the developer supply member 3 adheres to the surface of the developer carrier 2 and is transferred to the developer carrier 2 before being conveyed to the development region 30 facing the surface of the image carrier 1. A charging member (layer regulating member) 6 that is appropriately pressed is used to regulate the toner adhesion amount to a constant toner layer thickness.

  The charging member (layer regulating member) 6 is pressed against the developer carrier 2 at an appropriate pressure. The layer regulating member 6 is formed of a blade constituent member made of, for example, a plate-shaped metal material, and the antinode (surface) portion near the tip thereof is pressed against the developer carrier 2. Accordingly, the toner 7 supplied to the developer carrier 2 is regulated to a predetermined charge amount and thickness by a predetermined set pressure and a set position of the layer regulating member 6, and a development region 30 that is in contact with the image carrier 1 in a facing manner. It is conveyed to. One end of the layer regulating member 6 is fixed to the developing device 8 side, and the antinode portion on the free end side of the other end is provided in pressure contact with the surface of the developer carrier 2. The layer restricting member 6 is made of, for example, a phosphor bronze having a thickness of about 0.1 to 0.2 mm, or a metal plate such as stainless steel (SUS). The abdominal portion in the vicinity of the tip is pressed in the direction (the rotation axis direction of the developer carrier). As a result, the amount of the one-component developer 7 carried on the surface of the developer carrier 2 via the developer supply member 3 is made constant by the layer regulating member 6, and the developing region 30 is brought into contact with the image carrier 1. It is conveyed.

Also in this layer regulating member 6, a predetermined voltage Vd is supplied from the bias power supply circuit 10. Also in the bias voltage Vd, a larger value is set on the negative polarity side in the direction in which the toner 7 is pushed out toward the developer carrying member 2, for example, in the case of negative polarity toner. Further, the bias voltage Vd supplied to the layer regulating member 6 may be set to the same potential as the developing bias voltage Vb supplied to the developer carrier 2 or to a large value in absolute value. The charging member 6 regulates the toner adhesion amount on the developer carrier 2 to about 0.4 mg / Cm ^{2 to} 0.7 mg / Cm ² and the toner charge amount to about −15 μC / g to −30 μC / g. The

  On the other hand, the toner 7 conveyed to the developing region 30 facing the image carrier 1 is selectively attached according to the electrostatic latent image formed on the surface of the image carrier 1, and the electrostatic latent image is attached to the toner color. To visualize. The toner 7 that has not contributed to the development is returned to the developer hopper 34 by the rotation of the developer carrier 2. At the position where the toner is removed, a toner neutralizing member 5 is provided in pressure contact with the developer carrier 2. The charge eliminating member 5 is disposed in front of the developer carrying member 2 in the rotation direction of the developer supplying member 3, and one end portion thereof is fixed to the developing device 8 so as to be in pressure contact with the developer carrying member 2 appropriately. The belly on the free end side is brought into pressure contact using a spring property having a region where the developer carrier 2 is in pressure contact.

  The neutralizing member 5 is disposed in front of the developer carrying member 2 in the rotation direction of the developer supplying member 3, and one end portion thereof is fixed to the developing device 8 so as to be in pressure contact with the developer carrying member 2 appropriately. The end belly is brought into pressure contact using a spring property having a region where the developer is pressed against the developer carrier 2. If the charge eliminating member that also serves as the lower seal member is used as in the developing device 8 of FIG. 1, the contact pressure with respect to the developer carrier 2 is determined within a certain range because it also serves as the seal member. However, since it is not necessary to provide a static eliminating member separately from the seal member, it is advantageous in terms of the manufacturing cost of the developing device.

  In the present invention, the charge removal member 5 has a potential difference with the developer carrying member within 150 V, that is, a charge removal electric field within 150 V, and a material having good conductivity (not shown) is dispersed. As shown in FIG. 1, the static elimination member 5 is electrically at the same potential as the float or developer carrying member, and a static elimination electric field forming device or circuit element is connected between the developer carrying member and the static elimination member. Otherwise it is better.

  In the present invention, the residual toner is neutralized by the neutralizing member 5 that is floated or at the same potential as the developer carrying member, so that the neutralizing current does not flow to the neutralizing member 5 and the developer carrying member 2 and the neutralizing member. It is regulated so that the static elimination electric field does not work between 5.

  Further, the neutralizing member 5 in the present invention may be various conductive materials up to metals such as resin and SUS. Preferably, all of them are on the charging side of the toner 7 and on the same polarity side as the normal charging polarity of the toner. A material having good conductivity and being dispersed is formed. For example, as a material that is biased to the same polarity as the normal charging polarity of the toner in the charging series as compared with the toner 7, for negatively charged toner, polytetrafluoroethylene (PTFE), tetrafluoroethylene, polyfluoride, Fluorine resins such as vinylidene fluoride (PVDF), tetrafluoroethylene / perfluoropropyl vinyl ether (PFA) can be exemplified, and polyamide (nylon) and silicon resin can be exemplified for positively charged toner. As materials for adjusting the resistance of these materials, examples of materials having good conductivity to be dispersed include carbon, various conductive metal particles, and other suitable charge control substances. This dispersion includes application of a charge control substance. With the configuration of the developing unit 8, the toner on the developer carrying member 2 can be neutralized in consideration of the frictional power of the neutralizing member 5, so that an excessive neutralization current value (toner layer current value −5.0 μA or less) Even if there is no potential difference between the charge eliminating member 5 and the developer carrying member 2 or the charge eliminating current is not supplied to the charge eliminating member 5, development ghosts and afterimages can be prevented. Since the static elimination current itself does not flow, an overcurrent partially flows between the static elimination member 5 and the developer carrier 2, a discharge phenomenon occurs, the toner is deteriorated, the static elimination member 5 and the developer carrier It is possible to obtain an effect capable of preventing deterioration of the second-class developing device member. Further, the static elimination member 5 is electrically floated or at the same potential as the developer carrying member 2, and no static elimination electric field forming device or circuit element is connected between the developer carrying member 2 and the static elimination member 5. There is almost no potential difference between the toner carrier 2 and the developer carrier 2, and the weakly charged toner on the developer carrier 2 does not have a force to move toward the charge removal member 5, so that the weakly charged toner on the developer carrier 2, etc. It is possible to obtain an effect that can prevent the developer (toner) from adsorbing or staying and adhering to the nip portion or the vicinity of the neutralization member 5 over time. Accordingly, the developer carrying member 2 is not damaged by the toner fixed to or near the nip portion of the neutralizing member 5. Further, since excessive charge removal can be prevented and the occurrence of reverse polarity and weakly charged toner can be reduced, density unevenness due to uneven toner layer thickness on the developer carrier 2 can occur, or the reverse polarity and weakly charged toner can be used as a developer. It is possible to prevent the developer supply member 3 from getting into the eyes of the supply member 3 to harden the developer supply member 3 and scraping the developer carrier 2. Further, even after static elimination, the developer supply member 3 does not excessively scrape off the 2 toner on the developer carrier, so that after the toner is supplied from the developer supply member 3 to the developer carrier 2, the toner from the toner hopper Even when charged toner is supplied, there is a toner layer that maintains a certain amount of charge, and the developer carrying body 2 itself has a strong toner conveying force, such as weakly charged, reverse polarity, uncharged toner, or weakly charged, reverse polarity, uncharged toner. It is possible to obtain a developing device that can prevent soft aggregates due to charged toner or the like from being caught on the charging member 6 and prevent white streaks from being generated on the image. In addition, since the charge eliminating member 5 is electrically floated or has the same potential as the developer carrying member 2, the surface contacting the developer carrying member 2 or the charge removing member 5 itself is more charged than the developer. If the toner is not made of a material that is biased to the same polarity as the normal charging polarity of the toner), the ghost and the afterimage due to the development are deteriorated due to insufficient charge removal of the toner on the developer carrier 2 after development, and the charge removal member 5 and the developer carry If there is a potential difference between the bodies 2, an excessive potential difference occurs and the static elimination current may be less than −5.0 μA. As described above, ghosts and afterimages are caused by excessive static elimination of the toner on the developer carrier after development. Is improved, but the developer member is deteriorated and defects such as white streaks occur on the image.

  Further, the static elimination member 5 is made of polyvinylidene fluoride (PVDF) or tetrafluoroethylene / perfluoropropyl vinyl ether (PFA) type resin, which has a particularly high charging ability among the fluororesins. 5 can improve the charging capacity of the discharge member 5 and the developer carrier 2 and the excessive charge removal current value (−5.0 μA or less) that causes deterioration of the toner or the developer member. Further, it can be reduced or almost eliminated, and it is compatible with the prevention of development ghosts and afterimages.

The surface resistance value of the static elimination member 5 is preferably 10 ⁴ to 10 ⁹ Ω · Cm. As a result, the electrical resistance value of the static elimination member 5 is set to be equal to or greater than the electrical resistance value of the toner layer 15, so that an excessive potential difference occurs between the static elimination member 5 and the developer carrying member 2, and a partial excess occurs. A current flows (however, since the charge removal member 5 is floated, a current hardly flows into the charge removal member 5), a discharge phenomenon occurs, or the toner 15 on the developer carrier 2 is low after development or the toner An excessive potential difference is generated in a portion where there is almost no 15 (since the neutralization member 5 is floated, there is almost no potential difference between the neutralization member 5 and the developer carrier 2), and an overcurrent partially flows or discharges. Occurrence of the phenomenon can be reduced, and it is possible to prevent the toner 15 from being deteriorated and the developing member such as the charge removal member 5 and the developer carrier 2 from being deteriorated. This resistance value is preferably 10 ⁵ to 10 ⁷ Ω · Cm. As a result, it is possible to improve the accuracy of coexistence of stable charge removal and developer member deterioration due to discharge.

  Further, the developer charge amount Q / M on the developer carrying member 2 discharged by the charge removing member 5 is 20 to 70 of the developer charge amount Q / M on the developer carrying member 2 before the charge removal by the charge removing member 5. %, And more preferably 30 to 50%. As means for this configuration, various conditions such as triboelectric charging characteristics of the static elimination member 5, material such as strength, resistance value, pressing conditions, charging characteristics of the toner, doctor blade, developer carrier 2, developer supply member 3, etc. Is mentioned. For example, PVDF or PFA having a high frictional band power or PTFE having a slightly low frictional band power may be used to satisfy the above-mentioned Q / M for the triboelectric charging characteristics of the static elimination member 5. However, when the static elimination member 5 is set to the same potential as the float or the developer carrier 2, it is advantageous to use PVDF or PFA having a high frictional power. Moreover, you may adjust the surface resistance of the static elimination member 5 in order to satisfy Q / M mentioned above. Further, the pressing of the static elimination member 5 against the developer carrier 2 may be strengthened or weakened. Further, the charging characteristics of the developer carrier 2, the developer supply member 3, and the toner 7 may be adjusted so as to be the Q / M described above. With these configurations, it is possible to achieve a charge removal performance considering both the charge removal of the toner on the developer carrier 2 due to frictional charge of the charge removal member 5 and the current of the toner layer charge amount, and the accuracy of charge removal can be improved. Since it is possible to improve the accuracy of preventing image defects such as development ghosts and afterimages, and the charge removal performance is to obtain the minimum charge removal effect, an excessive charge removal current value above the toner layer current value (-5.0 μA or less). Or, since the current does not flow to the static elimination member itself (since the static elimination member 5 has the same potential as the float or the developer carrier 2, the current hardly flows into the static elimination member 5), and therefore between the static elimination member 5 and the developer carrier 2. As a result, an overcurrent partially flows or a discharge phenomenon occurs to deteriorate the toner (since the charge removal member 5 has the same potential as the float or the developer carrier 2, electric current is generated between the charge removal member 5 and the developer carrier 2. There is seldom caused discharge occurring difference), those capable of preventing from degrading the discharging member 5 and the developer carrying member 2, and the like developing device member. Further, it is possible to further improve the accuracy of preventing excessive charge removal, and to reduce the occurrence of reverse polarity and weakly charged toner with high accuracy, resulting in uneven density due to uneven toner layer thickness on the developer carrier 2, The reverse polarity and the weakly charged toner enter a large amount into the eyes of the developer supply member 3 to harden the developer supply member 3 and the developer supply member 3 scrapes the developer carrier 2. Can be prevented. Further, even after static elimination, the toner on the developer carrier 2 is not scraped off excessively by the developer supply member 3, so that after the toner is supplied from the developer supply member 3 to the developer carrier 2, the toner from the toner hopper Even when charged toner is supplied, there is a toner layer that maintains a certain amount of charge, and the developer carrying body 2 itself has a strong toner conveying force, such as weakly charged, reverse polarity, uncharged toner, or weakly charged, reverse polarity, uncharged toner. It is possible to prevent the soft agglomerates due to the charged toner or the like from being caught on the charging member 6 and to further prevent the occurrence of white streaks on the image.

  Further, as shown in FIG. 1, an elastic member 13 is provided on the side of the charge removal member 5 opposite to the developing carrier 2. The elastic member 13 is inserted between the charge removal member 5 and the lower portion of the toner hopper 34 so as to be in contact therewith. The elastic member 13 can sufficiently bring the charge-removing member 5 into contact with the developer carrier 2, can reliably remove the charge of the toner layer 15 on the developer carrier 2 after development, and the toner It is possible to prevent leakage between the charge removal member 5 and the developer carrier 2. Furthermore, it is possible to prevent the toner from entering too much between the charge removal member 5 and the lower portion of the toner hopper 34 and causing the contact pressure of the charge removal member 5 to the developer carrier 2 to be excessive. As shown in FIGS. 1 and 2, the elastic member 13 can optimize the elasticity to prevent toner spillage and scattering and collect the toner 15 in the toner hopper 34 without accumulating. That is, the elastic member 13 is preferably composed of a foam containing a foamed dielectric and a foaming agent, so that the contact area between the elastic member 13 and the developer carrier 2 can be ensured, the static elimination efficiency is improved, and the contact Time load can be reduced.

  In particular, the foamed dielectric is one of EPDM, urethane, nylon, silicon, PET, PTFE, PVDF, natural rubber, nitrile butadiene rubber, chloroprene rubber, styrene butadiene rubber, butadiene rubber, isoprene rubber, and polynorbornene rubber. One is preferred.

  Further, the static elimination member 5 is set so that, for example, 0.2 to 0.7 mm bites into the developing carrier 2 and the nip between the developer carrier 2 and the static elimination member 5 is about 0.5 to 3 mm. Yes.

  In the present invention, the contact nip width between the charge eliminating member 5 and the developer carrier 2 is adjusted to 2 mm or less by adjusting the elasticity of the elastic member 13 between the charge eliminating member 5 and the lower portion of the toner hopper 34, and the developer ( The internal friction coefficient μt of the toner 15, the friction coefficient μrt between the developer and the developer carrier, and the friction coefficient μjt between the developer 15 and the charge eliminating member 5 are μjt <μt <μrt. With this configuration, the toner 15 on the developer carrying member 2 shortens the contact time with the surface of the charge eliminating member 5, and the friction resistance between the charge removing member 5 and the toner 15 is higher than the friction resistance between the developer carrying member 2 and the toner 15 and the toner. Since the toner does not stagnate in the nip portion of the neutralizing member 5 and the toner can be collected and the heat generated in the nip portion of the neutralizing member 5 is reduced, it is possible to prevent the toner from adhering to the neutralizing member 5.

  Further, the neutralizing member 5 according to the present invention has a tensile strength of 1 MPa or more. With this configuration, the nip portion of the neutralizing member 5 is formed by the external additive of the toner 7 on the developer carrier 2. Since the toner is not excessively worn or torn, it is possible to prevent the toner from being deposited and fixed on the nip portion of the static elimination member 5 and scraping the developer carrier 2 at that portion.

  Next, the operation of the developing device 8 assembled in this way will be schematically described with reference to FIGS.

  The toner 7 accommodated in the toner hopper 34 is supplied to the vicinity of the developer supply member 3 by the stirring supply member 7. (The agitation supply member 7 may not be provided.) Next, as described above, the developer supply member 3 and the developer support 2 rotating in the same rotation direction as the developer support 2 have the toner 7 as the developer. A voltage is applied so as to move from the supply member 3 to the developer carrier 2, and the toner 7 is supplied to the developer carrier 2 by the developer supply member 3, pre-charged and attached. The toner 16 adhering to the developer carrier 2 is conveyed to the vicinity of the charging member 6 provided on the developing region 30 on the receiving side of the developer carrier 2 in the rotation direction. The voltage described above is applied to the charging member 6, and the charging member 6 is charged to a predetermined toner layer thickness 15 and charge amount. The charged toner 15 adhering to the developer carrier 2 is conveyed to the development region 30 and visualizes (develops) the electrostatic latent image on the surface of the image carrier 1 as described above. After the development, the toner 7 remaining on the developer carrier 2 that has passed through the development region 30 is conveyed to the vicinity of the charge removal member 5 provided on the downstream side of the development region 30 in the rotation direction of the developer carrier 2. As described above, a predetermined material, resistance, strength, nip width, surface property, pressing condition, etc., that are electrically floated and can neutralize the toner 7 on the developer carrying member 2 are set in the static eliminating member 5. Then, the toner 7 on the developer carrier 2 is neutralized by the neutralizing member 5. Further, as shown in FIG. 2, the developer carrier 2 is pressed against the developer supply member 3 whose moving direction is opposite at the contact point with the carrier 2, whereby the toner 7 is held in the developer carrier. It is peeled (scraped off) from the body 2, collected in the toner hopper 34, and reused. An image is repeatedly formed by such a process.

  Next, the developer of the developer carrying member by the developer supplying member with respect to the frictional power of the neutralizing member, the degree of toner fixing to the nip portion of the neutralizing member over time with respect to the electric field between the static eliminating member and the developer carrying member. The scraping effect of (toner) will be described with reference to FIGS.

  When the negatively charged toner is used, the frictional band power is “large” when the above-described neutralizing member 5 is PVDF or PFA, and the neutralizing member 5 and the developer carrier 2 are in a state where the frictional band power is “large”. When the static elimination electric field between them is “large” or “medium”, specifically, the developer (toner) charge amount Q / M on the developer carrying member 2 neutralized by the above-described static elimination member 5 depends on the static elimination member 5. When the developer charge amount Q / M on the developer carrier 2 before static elimination is less than 20% of the charge amount Q / M, the static elimination effect is “large”. In this case, the weakly charged toner on the developer carrier 2 The weakly charged toner has a weak holding power to the developer carrier 2 and is easily peeled off, so that the weakly charged toner adsorbs or stays and adheres to the nip portion or the vicinity of the static elimination member over time. The developer carrying member is damaged by the stuck toner mass. In addition, an excessive potential difference is generated between the charge eliminating member 5 and the developer carrying member 2, an overcurrent partially flows, a discharge phenomenon occurs, the toner is deteriorated, and the charge removing member or the developer carrying member. In many cases, the developing device member is deteriorated. Furthermore, as described above, when the frictional band power is large and the static elimination electric field is large, since there is a tendency to become an excessive setting (about −10 to −100 μA) than the actual required static elimination current, a sufficient static elimination effect is obtained. Thus, the developer scraping effect after passing through the static elimination member is large or moderate (detailed description later), and no afterimage is produced. However, as described above, the partial removal between the static elimination member 5 and the developer carrier 2 is partially Overcurrent flows or discharge phenomenon occurs, deteriorates the toner, deteriorates the developer member such as the charge removal member 5 and the developer carrier 2, or creates a large amount of reverse polarity and weakly charged toner, Density unevenness due to uneven toner layer thickness on the carrier 2, or the opposite polarity and weakly charged toner enter a large amount into the eyes of the developer supply member 3, making the developer supply member 3 hard, Developer supply member 3 removes developer carrier 2. After the charge is removed, the toner is supplied from the developer supply member 3 to the developer carrier 2 in order to scrape off the toner on the developer carrier 2 by the developer supply member 3 excessively. Since there is a large amount of uncharged toner and the toner charge amount is low, the toner carrying force of the developer carrier 2 itself becomes weak. Therefore, weakly charged, reverse polarity, uncharged toner, etc., weakly charged, reverse polarity, uncharged toner, etc. This causes a problem that the soft aggregates are easily caught on the charging member and white streaks are generated on the image. Further, when the static elimination member 5 described above has a frictional band power “high” and the static elimination electric field between the static elimination member 5 and the developer carrier 2 is “small”, the static elimination electric field “large” or “medium” described above. The problem can not be solved completely by just reducing the degree of failure. In the present invention, it is more preferable that the above-described static eliminating member 5 has a static electric field of “None” while the frictional power is “large”. In this case, specifically, the developer (toner) charge amount Q / M on the developer carrier 2 that has been neutralized by the neutralization member 5 described above is the developer charge on the developer carrier 2 before the neutralization by the neutralization member 5. The amount of Q / M is 20% to 70%, and it is possible to achieve the charge removal performance considering both the charge removal of the toner on the developer carrier and the current of the toner layer charge amount due to the frictional charge of the charge removal member, and the improvement of the charge removal accuracy Therefore, the developer scraping effect after passing through the static eliminating member is moderately accurate (detailed explanation later), and the afterimage can improve the accuracy of preventing image defects such as development ghost and afterimage, and the minimum required Since the static elimination performance for obtaining the maximum static elimination effect is obtained, an excessive static elimination current value greater than or equal to the toner layer current value (−5.0 μA or less) or the current does not flow to the static elimination member itself. Between, partially overpower Or it flows, a discharge phenomenon occurs, or deteriorate the toner, from degrading the discharging member and the developer carrying member such as a developing device member can be prevented. Further, it is possible to further improve the accuracy of preventing excessive static elimination and to reduce the occurrence of reverse polarity and weakly charged toner with high accuracy, resulting in uneven density due to uneven toner layer thickness on the developer carrier. To further prevent the opposite polarity and weakly charged toner from entering a large amount into the eyes of the developer supply member, hardening the developer supply member, and scraping the developer carrier. Can do. Further, even after static elimination, since the toner on the developer carrier is not scraped off excessively by the developer supply member, uncharged toner is supplied from the toner hopper after the toner is supplied from the developer supply member to the developer carrier. However, there is a toner layer that maintains a certain amount of charge, the developer carrier itself has a strong toner conveying force, and is softly charged with weakly charged, reverse polarity, uncharged toner, etc. or weakly charged, reverse polarity, uncharged toner, etc. It is possible to prevent the aggregate from being caught by the charging member, and to further prevent the occurrence of white streaks on the image. Further, since the charge eliminating member is electrically floated or at the same potential as the developer carrying member, there is almost no potential difference between the charge removing member and the developer carrying member, and the weakly charged toner on the developer carrying member is directed toward the charge removing member. Since the moving force does not work, it is possible to prevent the developer (toner) such as weakly charged toner on the developer carrying member from adsorbing or staying and adhering to or near the neutralization member nip portion over time. The toner fixed in the vicinity is not damaged by the developer carrier. When the frictional power of the neutralizing member 5 is “medium” or “small” and the neutralizing electric field is “none”, specifically, the developer (toner) on the developer carrier 2 that has been neutralized by the neutralizing member 5 described above. ) When the charge amount Q / M exceeds 70% of the developer charge amount Q / M on the developer carrier 2 before the charge removal by the charge removal member 5, the charge removal member 5 is electrically floated or the developer carrier 2 Therefore, there is almost no potential difference between the charge eliminating member and the developer carrying member, and the weakly charged toner on the developer carrying member does not have a force to move toward the charge removing member. Although it is possible to prevent the developer (toner) such as weakly charged toner from adsorbing or staying and adhering to or near the nip portion of the static elimination member over time, the toner on the developer carrying member 2 after the static elimination in the developer supply member 3 can be prevented. Since there is almost no scraping, the toner 7 on the developer carrier 2 is almost completely removed. Etc. interchanged without grain diameter fluctuation of the developer carrying member 2 on the toner is large, development ghost occurs. Note that the neutralization electric field between the neutralization member 5 and the developer carrier 2 is set to “medium” or “large” by using a frictional power of “medium” or “small” for the neutralization member 5, and the neutralization effect is “medium”. In particular, the developer (toner) charge amount Q / M on the developer carrier 2 that has been specifically neutralized by the static elimination member 5 is equal to the developer charge amount Q / M on the developer carrier 2 before static elimination by the static elimination member 5. By setting M to 20% to 70%, the developer scraping effect after passing through the static elimination member becomes moderately accurate (detailed explanation later), and it is possible to prevent ghosts and afterimages and further prevent excessive static elimination. The accuracy can be improved, and the occurrence of reverse polarity and weakly charged toner can be accurately reduced, resulting in uneven density due to uneven toner layer thickness on the developer carrying member, Enter a large amount into the eye of the supply member, harden the developer supply member, The developer supply member can prevent the developer carrier from being scraped off, and the toner on the developer carrier is not scraped off excessively by the developer supply member even after static elimination, so that the toner is developed from the developer supply member. Even if uncharged toner is supplied from the toner hopper after being supplied to the developer carrier, there is a toner layer that maintains a certain amount of charge, and the developer carrier itself has a strong toner conveying force, weakly charged, reverse polarity In addition, it is possible to prevent uncharged toner or the like and weakly charged, reverse polarity, soft aggregates due to uncharged toner or the like from being caught on the charging member, and further prevent the generation of white streaks on the image. Since the potential is not the same as that of the developer carrier 2, the weakly charged toner on the developer carrier 2 has a force to move toward the charge removal member 5, and the weakly charged toner has a holding force on the developer carrier 2. Weak and easy to peel off Weakly charged toner adsorbed or accumulated deposits adhered to the charge removing member nip or near, damage the developer carrying member in the toner mass and the fixation. In addition, an excessive potential difference is generated between the static elimination member 5 and the developer carrying member 2, an overcurrent partially flows, a discharge phenomenon occurs, the toner is deteriorated, and the static elimination member 5 and the developer carrying are carried. The problem of deteriorating the body 2 remains. Therefore, the above-mentioned problems often occur due to the action of a static elimination electric field on the static elimination member 5 and the developer carrying member 2, and is not shown in FIG. 3.

  Next, the toner charging characteristics (toner fluidity) with respect to the toner external additive coverage, the image quality, and the fixing condition of the toner to the neutralizing member nip portion and the charging member over time will be described with reference to FIG. If the toner external additive coverage exceeds 100%, the number of external additives (silica, etc.) that desorb, liberate, and agglomerate significantly increases. These external additives are weakly charged or reversely charged. Or agglomerated to form large particles, and the retention force on the developer carrier 2 is weak and easy to peel off (particularly, agglomerated silica). Even if there is a potential difference between the static elimination member 5 and the developer carrier 2, the weak charge adsorbs or stays and adheres to the nip portion or the vicinity of the static elimination member 5 as shown in FIG. Using this portion as a nucleus, the toner also adheres and grows into a toner lump, damages the developer carrier 2 and becomes black stripes, weakly charged, reversed polarity, uncharged silica, etc., weakly charged, reversed polarity, Soft aggregates due to uncharged silica or the like get caught on the charging member, as shown in FIG. The silica external additive toner is adhered grow as nuclei, white streaks are generated on the image at that part. In addition, density unevenness due to uneven toner layer thickness on the developer carrier 2 is generated, and the opposite polarity and weakly charged particles (detached / free / aggregated silica, etc.) are in the eyes of the developer supply member 3. The developer supply member 3 is hardened, and the developer supply member 3 scrapes the developer carrier 2. Further, since the toner fluidity is good, the toner charging characteristics are good, the solid followability and the image uniformity are also good. On the other hand, when the external additive coverage is less than 80%, as shown in FIG. 4, there is almost no external additive (silica or the like) that desorbs / releases / aggregates, so these external additives are weakly charged. Since there is no material that is weakly held by the developer carrying member 2 because it is weakly charged, reversely charged, or agglomerated into large particles, the material stays and adheres to the charge removal member 5 or the charging member 6 There is almost no black streak or white streak as described above, but the charging characteristics and fluidity of the toner are lowered, and the image uniformity and the solid followability are lowered. If the external additive coverage of the toner of the present invention is 80 to 100%, more preferably 85 to 95%, as shown in FIG. There is almost no external additive (silica, etc.) that is free and aggregated, and there is almost no material that stays and adheres to the static eliminating member 5 or the charging member 6, so that black or white streaks as described above hardly occur, and toner flow Since the toner charging characteristics can be secured moderately (here, the toner fluidity and the toner charging characteristics are expressed as moderate and medium), the solid followability and the image uniformity can be secured as medium to good, and both Can be planned.

  Further, in the developing device of the present invention, the details of the operation mechanism and the effect when the static elimination member 5 is electrically floated or the same potential as the developer carrier 2 and no static elimination electric field will be described with reference to FIG. . First, when a static elimination electric field works between the static elimination member 5 and the developer carrying member 2, an excessive amount that is less than 20% of the developer charge amount Q / M on the developer carrying member 2 before the static elimination by the static elimination member 5 is obtained. In the case of static elimination, the charging amount of the toner on the developer carrier 2 is reduced in the charging member 6, the toner conveying force due to the electric force (mirror force) against the reaction force of the charging member 6 × the friction coefficient is reduced, and the toner is charged. It becomes difficult to pass through the member 6, and white streaks are likely to occur. In the nip portion of the static elimination member 5, even if the static elimination electric field is small, the negatively charged toner (in the case of negatively charged toner) has a large Coulomb force (force to move from the developer carrier 2 to the static elimination member 5) due to the static elimination electric field. In particular, the weakly charged toner tends to be attracted to the charge-removing member 5 and stay easily because the Coulomb force is superior to the electric force (mirror force) acting on the toner on the developer carrier 2. Then, the adhered toner grows and damages the developer carrier 2. On the other hand, when the charge removal member 5 is electrically floated, in the charging member 6, the toner conveying force is increased by the electric force (image force) × friction coefficient against the reaction force of the charging member 6 described above, and the toner is charged. It becomes easy to pass the member 6, and it becomes difficult to generate white stripes. Further, since the neutralizing member 5 has no Coulomb force acting from the developer carrier 2 to the neutralizing member 5, toner such as weakly charged toner hardly stays in the nip portion of the neutralizing member 5.

  Further, in the developing device of the present invention, the working mechanism and the effect when the external additive coverage of the developer is 80 to 100%, more preferably 85 to 95% are shown in FIGS. Will be described. First, when the toner external additive coverage is larger than the above-mentioned range, the external additive (silica or the like) that has been detached, liberated, or agglomerated (apparently large in particle size) in the charging member 6 has a small charge amount or vice versa. It is charged, and the electric force (image force) is reduced (because the image force is increased in inverse proportion to the square of the particle diameter), and the electric force (image force) against the reaction force of the charging member 6 is conveyed by the friction coefficient. The external force additive (silica, etc.) that is reduced in force, detached, liberated and agglomerated (apparently larger in particle size) becomes difficult to pass through the charging member 6 and adheres to that part, and further, the toner adheres to that part. , White streaks are likely to occur. In addition, in the nip portion of the static elimination member 5, the external additive (silica or the like) that has been detached, liberated, or agglomerated (apparently large in particle size) has a small charge amount or is reversely charged, and an electric force (mirror power) (The image power increases in inverse proportion to the square of the particle size), and even if the static elimination electric field is small, the external additives (silica, etc.) that are detached, liberated, and agglomerated (apparently large in particle size) The Coulomb force (force to move from the developer carrying member 2 to the charge removal member 5) due to the static elimination electric field is increased, and in particular, external additives (silica etc.) that have been weakly charged desorbed / released / aggregated (apparently larger in particle size) This Coulomb force is superior to the electric force (mirror image force) acting on the toner on the developer carrier 2 and tends to be attracted to the charge removal member 5 and stay. Then, an external additive (silica or the like) that has been detached, liberated, or agglomerated (apparently larger in particle size) grows, and the toner adheres and grows on that portion, damaging the developer carrier 2. If the static elimination member is floated, the Coulomb force will be weakened, and the retention / fixation of external additives such as silica will be reduced. Retention and sticking will not decrease. On the other hand, when the toner external additive coverage is 80 to 100% (less external additive such as desorbed / free / aggregated silica), the charging member 6 has weakly or reversely charged desorbed / free / aggregated silica, etc. Since there is almost no external additive, the electric force (mirror power) against the reaction force of the charging member 6 described above × the conveyance force due to the friction coefficient increases, and the toner easily passes through the charging member 6 and white lines are generated. It becomes difficult. Further, since the neutralizing member 5 has almost no external additive such as weakly or reversely charged desorbed / free / aggregated silica, the external additive on the toner adheres to the toner with a strong Coulomb force. In addition, adhesion of external additives such as silica and toner is reduced. Therefore, even if there is a static elimination electric field that acts from the developer carrying member 2 to the static elimination member 5, adhesion to the static elimination member 5 is greatly reduced. Further, even when the charge removal member 5 is a float, the toner and external additive transport force due to mirror image force is further increased (the external additive on the toner adheres to the toner with a strong Coulomb force), so that the external additive coverage is 80 to 80%. 100% effect is maintained. Accordingly, there are few external additives such as weakly charged or reversely charged desorbed / free / aggregated silica, and these hardly stay in the nip portion of the static eliminating member 5, so that the toner stays and is hardly fixed, and the developer carrier 2 is removed. There is almost no damage.

  Further, in the developing device of the present invention, when the developer volume average particle size is X in the particle size distribution of the developer, X × 1.4 to X × 1.82 ≦ 3.8%, X × 1 The details of the working mechanism and the effect when the coarse powder of the developer is cut so that .82 or more and ≦ 0.36% will be described with reference to FIG. First, when there are many coarse powders having a large particle size in the developer beyond the above-mentioned range, the toner having a large particle size in the charging member 6 has a small electric force (image force) (the image force is the square of the particle size). Therefore, the toner conveying force due to the electric force (image force) x friction coefficient against the reaction force of the charging member 6 is reduced, and the toner is less likely to pass through the charging member 6 and white lines are likely to occur. Become. In the nip portion of the static elimination member 5, the toner on the developer carrier 2 having a large particle size has a small mirror image force, and even if the static elimination electric field is small, the negatively charged toner (in the case of negatively charged toner) depends on the static elimination electric field. The Coulomb force (the force that moves from the developer carrying member 2 to the charge removal member 5) increases, and in particular, the weakly charged toner has this Coulomb force against the electric force (mirror power) that acts on the toner on the developer carrying member 2. It tends to win and be attracted to the charge removal member 5 and stay easily. Then, the adhered toner grows and damages the developer carrier 2. On the other hand, when the particle size is small (when coarse powder cut toner is used), in the charging member 6, the toner conveying force by the electric force (mirror force) × friction coefficient against the reaction force of the charging member 6 described above increases, and the toner Can easily pass through the charging member 6 and white streaks are less likely to occur. Further, in the static elimination member 5, the toner on the developer carrier 2 having a small particle size has a large mirror image force and adheres to the static elimination member 5 even when there is a static elimination electric field that acts from the developer carrier 2 to the static elimination member 5. Is greatly reduced. Further, even when the charge removal member 5 is a float, the conveying force due to the mirror image force is further increased, so that the effect of toner obtained by classifying and cutting coarse powder (toner having a small particle diameter) is maintained. Therefore, toner such as weakly charged toner hardly stays in the nip portion of the static elimination member 5 and hardly damages the developer carrier 2.

  Next, regarding the above-described scraping of the toner 7 on the developer carrying member 2 by the developer supplying member 3, the effect of scraping off the developer (toner) on the developer carrying member by the developer supplying member will be described. Will be described.

  The developer charge amount Q / M on the developer carrier 2 that has been neutralized by the charge eliminating member 5 described above is 20 to 70% of the developer charge amount Q / M on the developer carrier 2 before the charge removal by the charge eliminating member 5. In this range, the neutralization effect is set to “medium”, and the toner on the developer carrier 2 after the neutralization is not completely scraped off by the developer supply member 3, but a part of the toner (for example, 30 to 30 before the scraping). About 70%). As a result, the toner 7 on the developer carrier 2 is replaced to some extent, so that there is not much change in the particle size of the toner on the developer carrier 2, there is no uneven charging of the toner on the developer carrier, and development ghosting can be reduced. In addition, since the toner 7 is smoothly moved from the developer supply member 3 to the developer carrier 2 and the movement of the toner to the developer supply member 3 can be reduced, the toner supply to the developer supply member 3 is clogged. And the developer carrier 2 can be prevented from being scraped by the supply member becoming hard. In addition, since the charge amount of the toner on the developer carrying member does not extremely decrease, the occurrence of density unevenness due to uneven charging can be reduced, and a certain amount of toner transport force on the developer carrying member can be secured, so that the toner soft aggregation in the toner hopper 34 can be secured. An object does not stay in the vicinity of the charging member 6. Further, the charge removal effect is “high” (the developer charge amount Q / M on the developer carrying member 2 discharged by the charge removing member 5 is equal to the developer charge amount Q on the developer carrying member 2 before the charge removal by the charge removing member 5). / M of less than 20%), the toner on the developer carrier 2 after the charge removal is completely scraped off by the developer supply member 3. (For example, 70% or more before scraping) This is because the charge amount of the toner on the developer carrier 2 is considerably reduced by static elimination, and therefore the adhesive force between the developer carrier 2 and the developer 7 is weak, so the developer supply This is because the member 3 is easily scraped off. As a result, the toner 7 on the developer carrying member 2 is almost replaced, so that the variation in the particle size of the toner on the developer carrying member 2 is reduced, and the occurrence of development ghost can be reduced. Further, since the toner 7 is smoothly moved from the developer supply member 3 to the developer carrier 2 and the movement of the toner to the developer supply member 3 can be reduced, toner clogging to the developer supply member 3 is prevented. It is possible to prevent the developer carrier 2 from being scraped due to the occurrence of the hardness of the supply member. However, since the charge amount of the toner on the developer carrying member extremely decreases after static elimination, density unevenness occurs due to uneven charging of the toner on the developer carrying member, and it becomes impossible to secure the conveying force of the toner on the developer carrying member. The toner soft agglomerates in the toner stay in the vicinity of the charging member 6 and cause white streaks in the image. Furthermore, since most of the toner on the developer carrier 2 is scraped off by the developer supply member 3 after static elimination, when a high printing density is developed, there is insufficient toner supply from the developer supply member 3 to the developer carrier 2. Occurs and a blur occurs due to poor toner tracking. Further, the charge eliminating effect is “small” (the developer charge amount Q / M on the developer carrying member 2 discharged by the charge removing member 5 is equal to the developer charge amount Q on the developer carrying member 2 before the charge removal by the charge removing member 5). In the case of exceeding 70% of / M), there is almost no scraping of the toner on the developer carrier 2 by the developer supply member 3 after static elimination. (For example, 30% or less before scraping) This is large because the charge amount of the toner on the developer carrier 2 is not so much neutralized, and the adhesion between the developer carrier 2 and the developer 7 is large. This is because it is difficult to scrape off by the supply member. As a result, the toner 7 on the developer carrying member 2 is hardly replaced, so that the toner particle size variation on the developer carrying member 2 is large and a development ghost is generated. Further, since the toner 7 is not smoothly moved from the developer supply member 3 to the developer carrier 2 and the toner is moved to the developer supply member 3, the toner supply to the developer supply member 3 is clogged. Occurrence of the developer carrying member 2 due to the supply member becoming hard occurs. Further, since the charge amount of the toner on the developer carrying member can be maintained without being lowered, there is no density unevenness due to uneven charging of the toner on the developer carrying member, and it is possible to secure the conveying force of the toner on the developer carrying member. The toner soft agglomerates therein do not stay near the charging member 6.

  In the present invention, it is preferable that the pressing force of the developer carrier 2 and the charge removal member 5 is a tensile load of 30 to 100 gf or less. With this configuration, the charge-removing member is strongly applied to the developer carrier 2 to excessively remove the charge of the toner remaining on the developer carrier 2 after the development, thereby causing the above-described problems, or the developer carrier. 2 The upper toner layer cannot pass through the static elimination member 5 and causes toner leakage, or toner that is not limited to weakly charged toner stays and adheres to the upstream side of the nip portion of the static elimination member 5 to damage the developer carrier 2, When the pressing force of the static eliminating member 5 is weak, unless the static eliminating member 5 having a high frictional charging capability is used, a potential difference between the static eliminating member 5 and the developer carrier 2 is excessively or slightly increased in order to enhance the static eliminating effect. Therefore, the discharge is likely to occur between the static elimination member 5 and the developer carrier 2, and the toner stays and adheres to the nip portion of the static elimination member 5 (the weakly charged toner is eliminated from the developer carrier 2). The electric field moving to member 5 is Ku For), can be prevented from being degrading the various members, can be prevented developing device member deteriorates and stable charge elimination. Note that the tensile load of the pressing force of the developer carrying member 2 and the charge removing member 5 described above is 10 mm in width and thickness as shown in the schematic diagram of the method for measuring the pressing force of the discharging member and the developer carrying member in FIG. A 0.1 mm PET sheet is sandwiched between the developer carrying member 2 and the charge removal member 5 in the absence of toner, and the drawing load is measured.

  Next, specific embodiments of the developing device according to the present invention will be described.

Example 1
A developing device having a charge eliminating member, a developer carrying member, and a developer supplying member having the following specifications is attached to the image forming apparatus, and development ghost, solid uniformity, white streaks due to Life, and deterioration of developer members (developer) The degree of black streaks on the image due to wear and abrasion of the support was evaluated.
Static elimination member 5 (also serves as a lower seal member as shown in FIGS. 1B and 2B, and is in electrical contact with the developer carrier 2)
Material: (1) SUS
(2) Sheet in which carbon is dispersed in polytetrafluoroethylene (PTFE; Teflon (registered trademark)) type resin (3) Sheet in which carbon is dispersed in tetrafluoroethylene / perfluoropropyl vinyl ether (PFA) type resin ( 4) A sheet in which carbon is dispersed in polyvinylidene fluoride (PVDF) resin. Surface resistance value: about E3, 5Ω · Cm (when 10V · 15 seconds are applied) (in the case of resin sheet)
Thickness: 110-150μm
Nip width: 1.5-25mm
Biting into developer carrier 2: about 0.5 to 0.7 mm
・ Developer carrier 2
Material: Conductive silicone rubber Outer diameter: φ16
Volume resistance: E3-5Ω ・ Cm
Hardness: about 60 ° (JIS A)
・ Developer supply member 3
Material: Conductive urethane foam Outer diameter: φ13.2
Volume resistance: E4 ~ 6Ω ・ Cm
Hardness: Asker F approx. 70 °
Number of cells: 3.1 cells / mm or more As the photoreceptor, an OPC drum having a film thickness of about 20 μm and φ24, in which CGL and CTL are sequentially laminated on an aluminum base tube, was used. As the toner, a non-magnetic black toner having a volume 50% diameter of about 9.0 μm and an apparent density of 0.35 to 0.40 g / Cm ³ was used. Further, the charge amount of the toner on the developer carrier 2 is about −17 to −28 μC / g, and the toner layer thickness is about 0.43 to 0.60 mg / Cm ² . Further, the surface potential of the image carrier 1 was about −550 to −600V. Further, a polycarbonate intermediate transfer belt was used as a transfer device, and a transfer roller was used on the back side of the intermediate transfer belt in the transfer portion. The image carrier 1 (photosensitive member) is rotated at a speed of about 100 mm / s, and the developer carrier 2 is rotated with respect to the image carrier 1 at a circumferential speed ratio of 1.33 times with a rotation. The member 3 was rotated at a peripheral speed ratio of 0.52 with respect to the developer carrying member 2 by a bite amount of about 0.6 mm and against rotation (counter).

  Under the above conditions, a DC voltage applied to the static elimination member 5 or a Zener diode is inserted between the developer carrying member 2 and the static elimination member 5, and the static elimination electric field between the developer carrying member 2 and the static elimination member 5 is 150V ( For example, development bias -250V, supply bias to neutralization member 5 -100V) are fixed, and instead of the neutralization member 5 of various materials, the development ghost and solid followability are visually observed after printing, Life (1 job 3 sheets) , 800 sheets / day, total of about 1.4000 sheets printed) Image due to wear of developer carrier 2, presence or absence of black streaks on image due to scraping, and change in toner characteristics in Life (decrease in charge amount, increase in large particle size toner) The presence or absence of the occurrence of fine white stripes was observed. In the development ghost, several solid patch (20 × 20 mm) patterns are arranged in a portion corresponding to about two rotations of the developer carrier at the top of the image as shown in FIG. The latter half of the image corresponding to the third and subsequent rounds of the developer carrying member was confirmed with an image having a uniform halftone, full solid. Regarding the solid followability, the occurrence of full solids, white streaks and black streaks was confirmed by halftone. Furthermore, in addition to the above image, a natural image was also confirmed.

  The results are shown in (Table 1).

  In Table 1 above, “x” in the development ghost indicates a level at which the ghost can be clearly visually confirmed in the development ghost check pattern, the full solid, and the natural image. Further, Δ indicates a development ghost check pattern, and a ghost can be visually confirmed with a full solid, but a ghost is not noticeable in a natural image. A circle indicates a level at which the ghost is not noticeable in any pattern. Furthermore, for white and black stripes, × is a level at which half or less of the Life test (7000 sheets or less) and white and black stripes can be clearly confirmed in the halftone, and Δ is a Life test of 50 to 80% (7000 to 11000 sheets). A level at which white and black stripes can be clearly confirmed in the halftone, and ◯ indicates a level at which the white and black stripes are not noticeable even in the halftone even when the Life test is completed.

  The above results were the same for all of yellow, magenta, cyan, and black.

  The charge amount before static elimination in the table is the friction band power of the static elimination member 5, the resistance value, the potential difference (static elimination electric field) between the static elimination member 5 and the developer carrier 2, and the pushing of the static elimination member 5 to the developer carrier 2. It depends on pressure and the like. Further, in the charging series, the higher the triboelectric charging capability, the higher the static elimination capability, and the charge amount before static elimination tends to be small, which is effective in preventing development ghosts.

  Therefore, it is more preferable to select a material in which the surface of the charge eliminating member 5 that contacts the developer carrying member 2 is more charged than the developer, and the material is biased to the same polarity as the normal charging polarity of the developer (toner). It has been found that the prevention margin can be expanded. Further, in this experiment, the potential difference between the developer carrying member 2 and the charge removing member 5 was set to 150 V. However, the developer member deteriorated due to the discharge between the charge removing member and the developer carrying member, and the weakly charged toner on the developer carrying member was removed by the charge removing member. In order to prevent the developer carrying member from deteriorating by moving to the charge-removing member and preventing the developer carrying member from deteriorating, it is necessary to reduce or reduce the potential difference, and PFA and PVDF with a wide development ghost prevention margin are considered advantageous. It is done.

  Regarding the solid follow-up performance, if the charge eliminating effect is too high, the toner in the developing device 8 has a large reverse polarity or a low charge amount, and the supply capability of the developer supply member 3 becomes small, which is deteriorated. Was confirmed. On the contrary, even if the charge removal effect is too small, a large amount of developer remains on the developer carrier 2 after charge removal, so that the developer supply from the developer supply member 3 to the developer carrier 2 is smoothly performed. Therefore, the supply capacity of the developer supply member 3 is small, and it is confirmed that the developer supply member 3 deteriorates.

  In addition, it is considered that the white streak is caused by the decrease in the toner charge amount due to Life, the same phenomenon as when the charge eliminating effect is too high. Therefore, as will be described later, it is shown that margin design is necessary in view of a decrease in toner charge amount due to Life. Later, the potential difference between the charge eliminating member 5 and the developer carrying member 2 is reduced, or the charge removing member 5 is electrically floated or the developer carrying member 2 and the charge removing member 5 are set to the same potential, so that the discharge, weakness on the developer carrying member 2 is weakened. The following shows the results of a study for improving the deterioration of the developing device due to the occurrence of toner sticking to the static elimination member 5 by the static elimination electric field in which the charged toner moves to the static elimination member 5 and the expansion of the white stripe prevention margin due to the reduction in the toner charge amount.

(Example 2)
Next, PVDFI is used for the charge eliminating member 5 and magenta toner is used to change the potential difference between the charge eliminating member 5 and the developer carrier 2 (the potential difference of 0 V electrically floats the charge removing member 5). An experiment similar to that in Example 1 was performed using the charge eliminating member. The results are shown in (Table 2).

  The above results were the same for all of black, yellow, and cyan.

  Similar results were obtained at a process speed of 124 mm / sec.

  When the potential difference is 150 V, the charge removal effect is too high, so the toner conveying force is reduced, white streaks occur in the middle of the Life, or a discharge occurs between the developer carrier 2 and the charge removal member 5 to cause the developer carrier 2. Deterioration causes black streaks, and also reduces the toner scraping effect on the developer carrier 2 by the developer supply member 3, so that the developer carrier 2 wear due to toner clogging on the developer supply member 3 is also confirmed. On the other hand, reducing the potential difference between the charge eliminating member 5 and the developer carrying member 2 in the table or setting it to 0 (making the charge removing member 5 electrically float or the same potential as the developer carrying member 2) This means that the charge removal effect is lowered, that is, the smaller the value is, the higher the toner charge amount on the development carrier 2 before and after charge removal, so that the mirror image force of the toner on the development carrier 2 increases and the toner conveyance force increases. Prevents white streaks It was confirmed that it could be done. Further, reducing the potential difference can greatly reduce the discharge between the developer carrying member 2 and the charge removal member 5 and the flow of excessive charge removal current, and can prevent the developer carrying member 2 from deteriorating. . Further, when the potential difference is set to 0 V, since the static elimination electric field that moves from the developer carrying member 2 to the static elimination member 5 is eliminated, it is greatly reduced that the weakly charged toner on the developer carrying member 2 stays and adheres to the nip portion of the static elimination member 5. Thus, it was confirmed that the deterioration of the developer carrier 2 due to the toner fixing factor to the nip 5 of the static elimination member is significantly reduced. These mean that the mechanism described above with reference to FIG. 6 is verified.

  In addition, since the neutralization member 5 is PVDF and the potential difference is 150V, the neutralization effect is high. Therefore, the toner supply force from the developer supply member 3 to the developer carrier 2 is slightly reduced. It was confirmed that the toner followability is improved as the size is decreased. In addition, when the static elimination member 5 is PVDF, the development ghost is good even when the potential difference is 0 V, but it is considered that the static elimination capability by the friction band power of PVDF is high. On the other hand, in the case of PTFE, since the frictional power is slightly small, when the potential difference between the developer carrier 2 and the charge removal member 5 is set to 0 V, white streaks are reduced due to an increase in the charge amount, but the development ghost is slightly worsened. Since the effect of scraping off the toner on the developer carrier 2 by the developer supply member 3 is reduced, problems such as density unevenness also occur. In view of the above, when the potential difference between the developer carrier 2 and the charge removal member 5 in the table is 0 to 150 V, the charge amount before charge removal is in the range of −17 to −30 μC / g, and the charge amount after charge removal is before charge removal. If it satisfies 20 to 70% of the charge amount (more preferably 30 to 50%), it is possible to simultaneously prevent development ghost, poor toner followability, white streaks and black streaks due to excessive charge removal or excessive charge removal. At the same time, it is possible to prevent the developer carrier 2 from being worn due to toner clogging to the developer supply member 3 by reducing the supply power of the developer supply member 3, and to prevent the developer carrier 2 from being worn by excessive discharge current due to deterioration of the discharge. found. Note that, if the static elimination electric field is 0 V, the toner adhesion to the static elimination member 5 can be considerably reduced, but it has been confirmed that PVDF having a high frictional charging ability is advantageous for not deteriorating the development ghost. Further, from the results of (Table 2), the higher the frictional charging capability, the more the development ghost can be prevented even if the potential difference between the static elimination member 5 and the developer carrier 2 is reduced. It was found that the discharge at the black line can be prevented and the generation of black stripes can be reduced. Accordingly, the friction band power of the neutralizing member 5 in FIG. 3, how the toner adheres to the nip portion of the neutralizing member over time with respect to the electric field between the neutralizing member 5 and the developer carrier 2, and the developer against the neutralizing effect. All of the above contents were verified for the effect of scraping off the developer (toner) on the developer carrier 2 by the supply member 3.

  In addition, it is considered that the above-described effect can be expected even with a PFA (verified in Example 1) having a high frictional band power like the PVDF.

  Further, the ratio of the charge amount after static elimination to the level before static elimination is divided into three according to the magnitude of the static elimination effect, and the surface of the nip portion of the developer carrier 2 and the static elimination member 5 is observed, and the toner on the developer carrier 2 after static elimination. Table 3 shows the results of investigating the scraping effect, the developer carrying force of the developer carrier 2 and the developer supply force from the developer supply member 3 to the developer carrier 2.

  As shown in FIG. 5, the developer scraping effect after static elimination in the table is determined based on the remaining amount of toner on the nip between the developer carrier 2 and the developer supply member 3. The scraping effect is large, the state where most of the toner remains is small, and the middle is the middle.

  Regarding the developer transport force, the larger the charge amount after static elimination, the less the toner on the developer carrier 2 is scraped off by the developer supply member 3, and the toner with a certain amount of charge remains. Showed a tendency to increase. Conversely, the lower the charge amount after static elimination, the smaller the developer conveyance force, and the white stripes due to toner adhesion to the charging member 6 and the like. Similar results were obtained at a process speed of 124 mm / sec.

  Regarding the developer supply power, it was confirmed that the scraping effect was medium, that is, the charge removal effect was the best. When the scraping effect was great, it was confirmed that the developer charge amount after static elimination was too low, the developer entered the developer supply member 3, and the developer supply member became hard.

  Conversely, when the scraping effect is small, a large amount of developer remains on the developer carrier 2 after static elimination, so that the developer supply from the developer supply member 3 to the developer carrier 2 can be smoothly performed. It was confirmed that it was not broken. Therefore, it was also confirmed that the developer supply member 3 is clogged with the developer 7 and the developer supply member becomes hard. It has been confirmed that when these developer supply members 3 become hard, the developer carrier 2 is worn and scraped to develop black stripes.

  Further, when the developer carrier 2, the charge removal member 5, the developer supply member 3, and the toner 7 in the developing device 8 after the life are observed, as the charge removal effect increases, the discharge mark, toner adhesion, and development on the charge removal member increase. The toner supply member was clogged with toner, the developer carrying member was worn and scratched, and the toner deteriorated. Further, black streaks are likely to occur even if the charge removal effect is too small, the charge amount of the toner 7 on the developer carrier 2 after charge removal is high, and the scraping effect by the developer supply member 3 is small. This is probably because the toner supply from the supply member 3 to the developer carrier 2 is not smoothly performed, and the toner supply to the developer supply member 3 is easily clogged.

  From the above results, setting the charge amount after static elimination to a specific setting range (20 to 70% before static elimination) prevents development ghost, toner tracking failure, white streaks, and black streaks due to developer member deterioration. It turns out that it can be prevented.

(Example 3)
Next, using PVDFI as the charge eliminating member 5, the developer (toner) has an average particle size (X) of about 9 μm, an external additive coverage of 109 to 117% toner A, an average particle size (X) of about 9 μm, The same experiment as in Example 1 was performed by using the toner B having an external additive coverage of 87 to 94% and changing the potential difference between the static eliminating member 5 and the developer carrier 2 to 68,0V. The results are shown in (Table 4). The toner used was black and magenta toner.

  For 0 V, the charge removal member 5 was electrically floated.

  The above results were similar for both cyan and yellow.

  Similar results were obtained at a process speed of 124 mm / sec.

  In the table, the external additive coverage of the developer (toner) is set to 80 to 100% (more preferably 85 to 95%) because the developer charging property by the external additive, the image uniformity by optimizing the fluidity, and The solid follow-up performance can be improved and the external additives (silica, etc.) that can be detached, released, and aggregated can be greatly reduced with high accuracy, so it is weakly charged, reversely charged, or aggregated into large particles. In this case, since the retention force on the developer carrier 2 is weak and easily peeled off (particularly, agglomerated silica, etc.), there is almost no desorbed / free / agglomerated silica etc. (external additive). Whether or not there is a potential difference between the bodies 2, the weak charge is adsorbed or stays and accumulates at or near the nip portion of the static elimination member 5 over time, and the toner adheres to the toner mass using the fixed portion as a nucleus. Grows and damages the developer carrier 2 to become black streaks Door is almost eliminated. Further, since there are almost no reverse poles and weakly charged particles (such as detached, free, and agglomerated silica), density unevenness due to uneven toner layer thickness on the developer carrier 2 may occur, or these reverse poles and weakly charged particles. A large amount of (detached / free / aggregated silica, etc.) enters the eye of the developer supply member 3 to harden the developer supply member 3, and the developer supply unit 3 material scrapes the developer carrier 2. You do n’t have to. Further, since the conveying force on the developer carrier 2 is weak (particularly, aggregated into large particles), there is no weakly charged / reversely charged / aggregated particles (detached / free / aggregated silica, etc.), so weakly charged , The reverse pole, uncharged silica, etc., or soft aggregates of weakly charged, reverse pole, uncharged silica, etc. are caught by the charging member 6, and the toner is fixedly grown by using the caught external additive such as silica as a core. Thus, it was found that almost no white streak was generated on the image, and the mechanism as shown in FIG. 7 was verified. Further, setting the potential difference between the charge eliminating member 5 and the developer carrying member 2 to 0V means that the charge eliminating effect is lowered as described above. That is, the smaller the value, the higher the charge amount after the charge removal, so that the toner conveying force is increased. By increasing, it was confirmed that the effect of setting the coverage ratio of the external additive to 80 to 100% can prevent the generation of white stripes with higher accuracy. Further, since there is no electric field for the weakly charged toner, the detached / free / aggregated silica, or the like to move from the developer carrying member 2 to the charge removal member 5, the toner and external additive (silica, etc.) stay and adhere to the nip portion of the charge removal member 5. It has been found that the deterioration of the developer carrier 2 can be prevented with higher accuracy.

Example 4
Next, using PVDFI as the charge eliminating member 5, the developer (toner) has an average particle size (X) of about 9 μm, a particle size of 12.7 to 16 μm is 5.5%, and a toner of 16 μm or more is 0.36%. A, neutralizing member 5 and developer using toner B (coarse powder cut toner) having an average particle size (X) of about 8.8 μm, a particle size of 12.7 to 16 μm of 25%, and a size of 16 μm or more of 0.2% The same experiment as in Example 1 was performed by changing the potential difference of the carrier 2 to 68,0V. The results are shown in (Table 5). As the toner, black toner was used.

  For 0 V, the charge removal member 5 was electrically floated.

  The above results were the same for any of cyan, magenta, and yellow.

  Similar results were obtained at a process speed of 124 mm / sec.

  By cutting the coarse powder of the developer (toner) in the table, it is possible to reduce the fluctuation of the particle diameter before and after the development by selecting the particle diameter of the development, so that it is possible to prevent the fluctuation of the specific charge of the toner on the developer carrier 2. Development ghosts and afterimages can be prevented, and coarse powder toner accumulation in the developing device 8 due to the progress of particle size selection can be prevented. For example, density unevenness due to uneven toner layer thickness on the developer carrier 2 can be generated. Deterioration of the image quality, the opposite polarity and the weakly charged toner enter a large amount into the eyes of the developer supply member 3 to harden the developer supply member 3, and the developer supply member 3 scrapes the developer carrier 2. Or the coarsely charged toner itself or the reversely charged toner, the uncharged toner, or the soft agglomerate stays and adheres to the charging member 6 or the neutralizing member nip portion or in the vicinity thereof to generate white streaks and damage the developer carrier 2. Prevents black streaks from entering Kill it turned out, a mechanism such as that shown in Fig. 8 has been confirmed verification. Further, setting the potential difference between the charge eliminating member 5 and the developer carrying member 2 to 0V means that the charge eliminating effect is lowered as described above. That is, the smaller the value, the higher the charge amount after the charge removal, so that the toner conveying force is increased. As a result, it was confirmed that the toner effect obtained by classifying and cutting coarse powder can prevent white streaks with higher accuracy. Further, since there is no electric field for the weakly charged toner to move from the developer carrying member 2 to the charge eliminating member 5, the staying and fixing of the toner at the nip portion of the charge removing member 5 is further eliminated, and the deterioration of the developer carrying member 2 can be prevented with higher accuracy. found.

(Example 5)
Next, development ghost, toner followability, white streak generation, and black streak generation due to the pressing force of the developer carrying member 2 and the charge removing member 5 were evaluated (fixed to the developer carrying member and the charge removing member 68V).

  The results are shown in (Table 6).

The pulling-out load was measured by sandwiching between the agent carrier and the charge removal member.

  Similar results were obtained at a process speed of 124 mm / sec.

  From the results of (Table 6), as described above, when the pressing force is 30 gf or less, the static elimination effect is reduced, the development ghost is generated, and the pressing force is small. There is a case where the toner stays in the member 5, and the developer carrier 2 is scraped off by the toner and a black streak may occur. Further, since the charge eliminating effect is too small, the toner followability is lowered for the reason described above, and the occurrence of white stripes is reduced.

  On the other hand, if it is 100 gf or more, the charge eliminating effect is too high, and as described above, the toner followability is lowered, and white lines and black lines are also generated. On the other hand, if the pressing force is too high, the toner on the developer carrying member is scraped off by the neutralizing member 5 and toner leakage occurs outside the developing device, or the toner adheres to the nip portion of the neutralizing member 5 and the developer. It was confirmed that the carrier 2 was deteriorated.

  Further, heat was generated between the developer carrying member 2 and the charge removal member 5, and a phenomenon in which toner was fused to the nip of the charge removal member 5 was often observed. There was a high possibility that the developer carrier 2 was scraped with the fused toner, and there was a tendency for black streaks to occur.

  Accordingly, it has been found that by optimizing the pressing force of the developer carrier 2 and the charge eliminating member 5, development ghost, toner followability, white streak generation and black streak generation can be reduced.

(Example 6)
Next, development ghost, toner followability, white streak generation and black streak generation by the peripheral speed ratio SR (counter) of the developer supply member 3 with respect to the developer carrier 2 at a process speed of 100 mm / sec and 124 mm / sec. Evaluation was performed (fixed to the developer carrying member and the charge removal member 68V).

  The results are shown in (Table 7) (process speed 100 mm / sec) and (Table 8) (process speed 124 mm / sec).

  From the results of (Table 7), when the process speed is 100 mm / sec, black streaks are generated due to deterioration of the developer carrier 2 when the peripheral speed ratio of the developer supply member 3 to the developer carrier 2 is 0.47 or less. However, the ability to supply the developer carrier 2 from the developer supply member 3 to the development carrier 2 is lowered, and the toner followability is deteriorated. Further, the charge imparting ability is also lowered, so that the toner charge amount on the developer carrier 2 is lowered, white streaks due to a decrease in toner conveying force and density unevenness are caused. When the peripheral speed ratio is 0.58 or more, the toner on the developer carrier 2 itself or the developer carrier 3 is deteriorated, or the toner remaining on the development carrier 2 after development is excessively scraped off or developed. The developer carrier 2 and the developer are rubbed too much to produce a large amount of reverse polarity and weakly charged toner, causing density unevenness due to uneven toner layer thickness on the developer carrier, or the reverse polarity and weakly charged toner Gets into the eyes of the developer supply member, or the developer on the developer supply member 3 is melted by frictional heat to harden the developer supply member 3, and the developer supply member 3 becomes the developer carrier 2. Black stripes are generated by shaving. In addition, after the charge is removed in the charge removal step, after the toner is supplied from the developer supply member 3 to the developer support 2 in order to scrape off the toner on the developer support 2 excessively by the developer supply member 3, Since there is a lot of uncharged toner from the toner hopper and the toner charge amount is low, the toner carrying force of the developer carrier itself becomes weak, so weakly charged, reverse polarity, uncharged toner, etc. or weakly charged, reverse polarity, uncharged Soft aggregates due to charged toner or the like are easily caught on the charging member, and white streaks are generated on the image. Further, in addition to the developer scraping and excessive friction by the developer supply member, the rotation speed of the developer supply member is increased, the amount of developer is embraced, resulting in a decrease in developer supply capability, It has been found that the follow-up property becomes worse. When the peripheral speed ratio is 0.47 to 0.58, the developer supply capability and the charge imparting capability of the developer supply member 3 are ensured, the toner and the developer support 2 are not deteriorated, and the toner on the developer support is It has been found that the above-mentioned problems are almost eliminated because the conveying force is also kept strong.

  From the results of (Table 8), when the process speed is 124 mm / sec, if the peripheral speed ratio of the developer supply member 3 to the developer carrier 2 is not more than 0.3.8, black due to deterioration of the developer carrier 2 Although streaks are improved, the supply capability from the developer supply member 3 to the development carrier 2 is lowered, and the toner followability is deteriorated. Further, the charge imparting ability is also lowered, so that the toner charge amount on the developer carrier 2 is lowered, white streaks due to a decrease in toner conveying force and density unevenness are caused. When the peripheral speed ratio is 0.47 or more, the toner on the developer carrier 2 itself or the developer carrier 3 is deteriorated, or the toner remaining on the development carrier 2 after development is excessively scraped off or developed. The developer carrier 2 and the developer are rubbed too much to produce a large amount of reverse polarity and weakly charged toner, causing density unevenness due to uneven toner layer thickness on the developer carrier, or the reverse polarity and weakly charged toner Gets into the eyes of the developer supply member, or the developer on the developer supply member 3 is melted by frictional heat to harden the developer supply member 3, and the developer supply member 3 becomes the developer carrier 2. Black stripes are generated by shaving. In addition, after the charge is removed in the charge removal step, after the toner is supplied from the developer supply member 3 to the developer support 2 in order to scrape off the toner on the developer support 2 excessively by the developer supply member 3, Since there is a lot of uncharged toner from the toner hopper and the toner charge amount is low, the toner carrying force of the developer carrier itself becomes weak, so weakly charged, reverse polarity, uncharged toner, etc. or weakly charged, reverse polarity, uncharged Soft aggregates due to charged toner or the like are easily caught on the charging member, and white streaks are generated on the image. Further, in addition to the developer scraping and excessive friction by the developer supply member, the rotation speed of the developer supply member is increased, the amount of developer is embraced, resulting in a decrease in developer supply capability, It has been found that the follow-up property becomes worse. In the case of the peripheral speed ratio of 0.3.8 to 0.47, the developer supply ability and the charge imparting ability of the developer supply member 3 are ensured, the toner and the developer support 2 are not deteriorated, and the developer support is provided. Since the upper toner conveying force is also kept strong, it has been found that the above-mentioned problems are almost eliminated.

  Further, it has been found that it is preferable that 47 / process speed ≦ SR ratio (counter) ≦ 58 / process speed as a condition of the peripheral speed ratio SR of the developer supply member 3 in order to eliminate the above-mentioned problems.

  As described above, Examples 1 to 7 support the actions and effects described above.

  As described above, the developing device and the image forming method according to the present invention have the effect of preventing development ghost, toner follow-up failure, density unevenness, as well as generation of white streaks and black streaks due to deterioration of the developer member. It is useful as a photographic developing device, particularly a contact developing type non-magnetic one-component developing device.

Schematic showing a developing device in an embodiment of the present invention Schematic illustrating the detailed steps of development, charge removal, developer supply, and charging (thinning) section in the developing device according to one embodiment of the present invention. In the developing device according to the embodiment of the present invention, the friction band power of the static elimination member, the degree of toner fixing to the nip portion of the static elimination member over time with respect to the electric field between the static elimination member and the developer carrier, and the developer supply for the static elimination effect Explanatory drawing which shows the scraping effect of the developer (toner) on the developer carrying member by the member In the developing device according to one embodiment of the present invention, the external additive (toner) such as silica to the neutralizing member nip portion over time with respect to the external additive coverage of the developer (toner) and the toner charging characteristics (toner fluidity). Explanatory diagram showing fixing condition, fixing condition of external additive (toner) such as silica to charging member, and image quality Explanatory drawing which shows the scraping effect of the developer (toner) on the developer carrying member by the developer supply member with respect to the charge amount after static elimination and the static elimination effect in the developing device according to one embodiment of the present invention. Explanatory drawing which shows the effect at the time of making a static elimination member float in the image development apparatus in one embodiment of this invention. Explanatory drawing which shows the effect in the developing device in one embodiment of this invention when a developer (toner) outer coverage is 80-100%. Explanatory drawing which shows the effect at the time of using the toner which cut coarse powder in the image development apparatus in one embodiment of this invention. FIG. 4 is a schematic diagram illustrating a method for measuring the pressing force between a charge removal member and a developer carrier in the developing device according to the embodiment of the present invention. Diagram showing image pattern for evaluating development ghost 1 is a schematic diagram showing an overall structure of an image forming apparatus including a developing device according to an embodiment of the present invention. Schematic showing a conventional developing device Schematic explaining the detailed steps of development, static elimination, developer supply, and charging (thinning) section in a conventional developing device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image carrier 2 Developer carrier 3 Developer supply member 4 Stirring supply member 5, 105 Static elimination member 6 Charging member (layer regulation member)
7 Developer (toner)
8 Development Device 9 Power Supply for Developing Bias Voltage Supply 10 Power Supply for Charging Member Voltage Supply 11 Power Supply for Voltage Supply to Developer Supply Member 12 Power Supply for Voltage Supply to Charge Removal Member 13, 113 Backup Sponge 14 Charge Removed Developer (toner)
15 Charged developer (toner)
16 Supplied developer (toner)
17 Protection resistance 18 Power supply circuit for supplying voltage to the charge removal member 19 Developer (toner) staying and fixing in the vicinity of the charge removal member or charging member
DESCRIPTION OF SYMBOLS 23 Charger 24 Optical system 25 Transfer apparatus 26 Cleaning apparatus 27 Static elimination apparatus 28 Fixing apparatus 29 Image receiving paper 30 Development area 31 Registration roller 32, 33 Guide means 34 Developer (toner) hopper

Claims (18)

A rotatable image carrier carrying an electrostatic latent image; a rotatable, conductive and semiconductive developer carrier arranged in contact with the image carrier and carrying a one-component developer; A developing unit including a voltage applying unit to the developer carrying member; a developer supplying member that supplies the developer to the developer carrying member; and a development position where the developer carrying member and the image carrier are in contact with each other. A charging means having a charging member disposed upstream of the developer carrying member rotation direction to charge the developer and regulate the thickness of the developer layer on the developer carrying member, and the developer carrying than the developing position. In the developing device, comprising: a discharging unit that is disposed downstream of the body rotation direction and has a discharging member that discharges the developer charge remaining on the developer carrying member after the development at the developing position. The surface of the member that contacts the developer carrier or The charge eliminating member itself is formed of a material that is more biased than the developer on the same charging side as the regular charge polarity of the developer (toner), and the developer carrying member and the charge eliminating member A developing device in which a static elimination electric field of 150 V or less is formed therebetween. The neutralization member is electrically at the same potential as the float or the developer carrying member, and no static elimination electric field forming device or circuit element is connected between the developer carrying member and the neutralizing member. The developing device according to claim 1. The developing device according to claim 1, wherein the charge eliminating member is polyvinylidene fluoride (PVDF) or tetrafluoroethylene perfluoropropyl vinyl ether (PFA) resin. The developing device according to claim 1, wherein an external additive coverage of the developer is 80 to 100%. The developer charge amount Q / M on the developer carrying member neutralized by the charge eliminating member is 20 to 70% of the developer charge amount Q / M on the developer carrying member before the charge removal by the charge eliminating member. The developing device according to claim 1, wherein: In the particle size distribution of the developer, when the volume average particle size of the developer is X, X × 1.4 to X × 1.82 ≦ 3.8%, X × 1.82 or more ≦ 0.36% The developing device according to claim 1, wherein the developer has a particle size distribution of (coarse powder cut toner). Narrowing the particle size distribution and charge amount distribution of the developer, in particular, the CV value [%] representing the volume particle size distribution defined as CV = 100 × (standard deviation / average value) is within 25%. The developing device according to claim 1. The developing device according to claim 1, wherein a pressing force between the developer carrying member and the charge eliminating member is a tensile load of 30 to 100 go or less. 9. The developing device according to claim 1, wherein a peripheral speed ratio SR ratio between the developer carrying member and the developer supply member is 47 / process speed ≦ SR ratio (counter) ≦ 58 / process speed. . A rotatable image carrier carrying an electrostatic latent image; a rotatable, conductive and semiconductive developer carrier arranged in contact with the image carrier and carrying a one-component developer; And a developing step of forming a toner image by a developer (toner) on the image carrier by applying a voltage to the developer carrier in a developer supply member for supplying the developer to the developer carrier. When,
The developer is charged and the developer layer thickness on the developer carrier is charged by a charging member disposed upstream of the developing position where the developer carrier and the image carrier are in contact with each other in the rotation direction of the developer carrier. Charging process that regulates,
A neutralization step of neutralizing the charge of the developer remaining on the developer carrier after development at the development position by a neutralization member arranged downstream of the development position in the rotation direction of the developer carrier. In addition, the surface of the static elimination member that contacts the developer carrying member or the static elimination member itself is charged more than the developer in the same charging polarity as the normal charging polarity of the developer (toner). An image forming method, wherein a static elimination electric field of 150 V or less is formed between the developer carrying member and the static elimination member. The static elimination member has a static elimination step in which the static elimination electric field forming device or the circuit element is not connected between the developer carrier and the static elimination member, with the static elimination member being electrically at the same potential as the float or the developer carrier. The image forming method according to claim 10. 12. The image forming method according to claim 10, wherein the charge eliminating member is polyvinylidene fluoride (PVDF) or tetrafluoroethylene perfluoropropyl vinyl ether (PFA). The image forming method according to claim 10, wherein an external additive coverage of the developer of the charge eliminating member is 80 to 100%. The developer charge amount Q / M on the developer carrying member neutralized by the charge eliminating member is 20 to 70% of the developer charge amount Q / M on the developer carrying member before the charge removal by the charge eliminating member. 14. The image forming method according to claim 10-13. In the particle size distribution of the developer, when the volume average particle size of the developer is X, X × 1.4 to X × 1.82 ≦ 3.8%, X × 1.82 or more ≦ 0.36% The image forming method according to claim 10, wherein the developer has a particle size distribution (coarse powder cut toner). The developer has a narrow particle size distribution and charge amount distribution, and in particular, a CV value [%] representing a volume particle size distribution defined as CV = 100 × (standard deviation / average value) is within 25%. The image forming method according to claim 10. 17. The image forming method according to claim 10, wherein the pressing force of the developer carrying member and the charge eliminating member is a tensile load of 30 to 100 go or less. The peripheral speed ratio SR ratio between the developer carrier and the developer supply member is 45 / process speed (mm / sec) ≦ SR ratio (counter) ≦ 60 / process speed (mm / sec). The image forming method according to claim 10.

Images