JP2008090188A - Developing device, image forming apparatus and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device and a toner cartridge generating no image with development pitch irregularity and having high reliability by smoothing pumping failure of a developer by a regulating means, the failure caused by a stirring and conveying means in an electrophotographic system. <P>SOLUTION: The developing device includes a first stirring means that conveys a developer while stirring, a second stirring means that is disposed in an opposite side of a developer carrier with respect to the first stirring means, and a partition wall between the first and second stirring means, wherein a regulating member regulating an amount of the developer on the developer carrier is disposed above the developer carrier. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus, such as a copying machine, a printer, a facsimile machine, or a complex machine thereof, and an image forming apparatus having a developing device and a process cartridge, and more particularly, a developer stirring and conveying for two-component development It relates to means.

  2. Description of the Related Art Conventionally, a two-component developing device using a two-component developer composed of a non-magnetic toner and a magnetic carrier has been used as a device for revealing an electrostatic latent image formed on an image carrier. This two-component developing device stirs the toner replenished from a separately provided toner supply unit by a stirring means in the developing device and carries it on the developer carrying member, and uses this developer to An invention for visualizing an electrostatic latent image is known (see, for example, Patent Document 1).

The toner from the toner supply unit is carried on the developer carrying member while being sufficiently stirred and transported by the stirring means. However, if the amount of the developer is too small, the height of the developer surface is lowered, and the developer carrying member is lowered. Is insufficient, and stirring and conveying means, that is, screw pitch unevenness occurs in the image. In order to prevent this, if the amount of developer is increased and the height of the surface of the developer is increased, it has become a mainstream to provide a developer storage space in a recent developing device and store the developer in the developing device in advance. Therefore, there is a limit to the amount, and it is difficult to secure a developer amount sufficient to make the surface of the agent sufficiently high.
JP 2004-69789 A

  However, in the above-described invention of Patent Document 1, since toner is supplied into the developer, the amount of toner taken in varies depending on the height (pressure) of the developer surface. Further, because of the space in the developer carrier and the conveying screw part, there is a problem that the height of the developer surface cannot be sufficiently maintained and screw pitch unevenness is likely to occur.

  Recently, in order to reduce the torque of the developing device or reduce the stress on the developer, there are many developing devices that set a small amount of developer to be pumped up and held by the developing roller. However, in this case, the influence of the shake of the first stirring means appears remarkably, and when the first stirring means having a bad shake or the like is used, an abnormal image such as screw pitch unevenness may appear on the image. This phenomenon is particularly noticeable in the central portion where the influence of vibration is likely to occur (easy to bend) due to strength.

  The present invention has been made in consideration of the above-described circumstances, and a developer layer thickness restricting body is provided at a position that contacts the developer moving on the developer carrying body to solve the above problems. Further, by increasing the strength of the first conveying means, the effect of smoothing the developer pumping failure (pitch unevenness) by the agitating and conveying means by the regulating means, and the development of the developing pitch unevenness image by strengthening the developer agitation at the regulating portion An object of the present invention is to provide a developing device and a process cartridge (toner cartridge) with high reliability.

  In order to solve the above-described problems, the invention described in claim 1 includes a first agitation unit that conveys the developer while agitating, and a developer carrier opposite to the first agitation unit. A developing device having a second agitating means provided and a partition wall between the first and second agitating means, wherein the amount of developer on the developer carrier is regulated above the developer carrier. It is a developing device having a regulating member to be used.

  According to a second aspect of the present invention, there is provided a first agitating means having a regulating member that regulates the amount of developer on the developer carrying member on the upper side, and conveying the developer while stirring, and the first stirring And a developing device having a partition wall between the first stirring means and the second stirring means provided on the opposite side of the developer carrying member with respect to the means. A developer layer thickness regulating shape is attached to the partition wall so as to come into contact with the developer moving on the upper developer carrying member, and the central axis of the first conveying means is more than the shafts at both ends. It is a developing device with increased strength.

  According to a third aspect of the present invention, there is provided a first agitating means having a regulating member that regulates the amount of developer on the developer carrying member on the upper side, and conveying the developer while stirring, and the first stirring And a developing device having a partition wall between the first stirring means and the second stirring means provided on the opposite side of the developer carrying member with respect to the means. A developer layer thickness regulating shape is attached to the partition wall so as to come into contact with the developer moving on the upper developer carrying member, and the shaft diameter of the central portion of the first conveying means is set to the shaft diameter of both ends. It is characterized by being a thicker developing device.

  According to a fourth aspect of the present invention, in the developing device according to the second or third aspect, the central portion of the first developer agitating means and both end portions are connected with the strength between the central portions. Or it connected through the connecting member which has a taper and connects, It is characterized by the above-mentioned.

  A fifth aspect of the present invention is the developing apparatus according to any one of the first to fourth aspects, wherein a developer having a magnetic carrier particle size of 20 to 50 μm is used.

  According to a sixth aspect of the present invention, in the developing device according to any one of the first to fifth aspects, the magnetic carrier particles of the developer are obtained by coating a core material of a magnetic material with a resin coat film. The resin-coated film contains a resin component obtained by crosslinking a thermoplastic resin and a melanin resin, and a charge adjusting agent.

  According to a seventh aspect of the present invention, in the developing device according to any one of the first to sixth aspects, the toner of the developer is a polyester prepolymer having at least a functional group containing a nitrogen atom, a polyester, a coloring A toner obtained by subjecting a toner material liquid in which an agent and a release agent are dispersed in an organic solvent to at least one of a crosslinking reaction and an extension reaction in an aqueous medium.

  The invention described in claim 8 is the developing device according to claim 7, wherein the toner has a volume average particle diameter of 3 to 8 μm, and has a volume average particle diameter (Dv) and a number average particle diameter (Dn). The ratio (Dv / Dn) is in the range of 1.00 to 1.40.

  According to a ninth aspect of the present invention, in the developing device according to the seventh or eighth aspect, the toner has a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 180. It is in the range.

  According to a tenth aspect of the present invention, in the developing device according to any one of the seventh to ninth aspects, the toner has a substantially spherical shape, the major axis r1, the minor axis r2, and the thickness r3. (Where r1 ≧ r2 ≧ r3), the ratio of the major axis r1 to the minor axis r2 (r2 / r1) is in the range of 0.5 to 1.0, the thickness r3 and the minor axis The ratio to r2 (r3 / r2) is in the range of 0.7 to 1.0.

  According to an eleventh aspect of the present invention, there is provided an image carrier that carries an electrostatic latent image, a charging device that charges the image carrier, and a developer that carries the developer on the developer carrier and that faces the image carrier. A developing device that transports the toner image to the area and develops the latent image on the image carrier to form a toner image, and removes residual toner remaining on the image carrier after the developed toner image is transferred to a transfer material An image forming apparatus using the developing device according to any one of claims 1 to 9 as the developing device.

  According to a twelfth aspect of the present invention, there is provided an image carrier that carries an electrostatic latent image, a charging device that charges the image carrier, and a developer that carries the developer on the developer carrier and that faces the image carrier. A developing device that transports the toner image to the area and develops the latent image on the image carrier to form a toner image, and removes residual toner remaining on the image carrier after the developed toner image is transferred to a transfer material In the image forming apparatus having the cleaning device, the image carrier and the device including at least the developing device selected from the developing device, the charging device, and the cleaning device are integrally supported, and the image forming device A process cartridge that is detachably attached to the main body is a process cartridge that uses the developing device according to any one of claims 1 to 10 as the developing device.

  According to the present invention, in a developing device that develops a latent image using a developer, the developing device has a regulating member that regulates the amount of developer on the developer carrier above the developer carrier, and the developer Between the first and second agitating means, a first agitating means that conveys while agitating, a second agitating means provided on the opposite side of the developer carrier relative to the first agitating means, and In the developing device having a partition wall, a developer layer thickness regulating shape is attached to the partition wall at a position in contact with the developer moving on the developer carrier above the first stirring means, and The developing device characterized in that the shaft diameter of the central portion of one transport means is thicker than the shaft diameters of both ends thereof, the shaft is not bent, the vibration is improved, and the adverse effect on the pumping up of the developer in the central portion in the longitudinal direction is reduced. At the same time, the developer is not pumped up correctly by the conveyance Stirring the developer in an effective and regulating unit level the Chimura) in regulating member makes it possible to provide a high developing device reliability without occurrence of development uneven pitch image by become stronger.

  Hereinafter, a developing device and a process cartridge according to the present embodiment will be described in detail with reference to the drawings.

  An example of an embodiment in which the present embodiment is applied to an electrophotographic direct color transfer color laser printer (hereinafter referred to as “laser printer”) as an image forming apparatus will be described with reference to FIGS.

  FIG. 1 is a schematic configuration diagram of a laser printer according to the present embodiment. This laser printer includes four toner image forming units 1Y, 1M, 1C, 1K (hereinafter referred to as “yellow” (Y), magenta (M), cyan (C), and black (K)). The subscripts Y, M, C, and K of the reference numerals indicate yellow, magenta, cyan, and black members, respectively, and the direction of movement of the transfer paper 100 (the belt 60 along the arrow A in the figure). In the traveling direction) from the upstream side. Each of the toner image forming units 1Y, 1M, 1C, and 1K includes photosensitive drums 11Y, 11M, 11C, and 11K as image carriers and a developing unit. In addition, the arrangement of the toner image forming units 1Y, 1M, 1C, and 1K is set so that the rotation axes of the photosensitive drums are parallel and arranged at a predetermined pitch in the transfer paper moving direction. .

  In addition to the toner image forming units 1Y, 1M, 1C, and 1K, the laser printer used in the example of the present embodiment carries the optical writing unit 2, the paper feed cassettes 3 and 4, the registration roller pair 5, and the transfer paper 100. A transfer unit 6 as a belt driving device having a transfer conveyance belt 60 as a transfer conveyance member that conveys the toner image forming unit so as to pass through a transfer position, a belt fixing type fixing unit 7, a paper discharge tray 8, and the like. I have. In addition, a manual feed tray MF and a toner supply container TC are provided, and a waste toner bottle, a double-sided and / or reversing unit, a power supply unit, and the like (not shown) are also provided in a space S indicated by a two-dot chain line.

  The optical writing unit 2 includes a light source, a polygon mirror, an f-θ lens, a reflection mirror, and the like, and scans the surface of each photosensitive drum 11Y, 11M, 11C, 11K with light from a laser beam or the like based on image data. Irradiate while.

  The one-dot chain line in FIG. 1 shown above indicates the conveyance path of the transfer paper 100. The transfer paper 100 fed from the paper feed cassettes 3 and 4 or the manual feed tray MF is transported by transport rollers while being guided by a transport guide (not shown), and is transported to a temporary stop position where the registration roller pair 5 is provided. The transfer paper 100 delivered at a predetermined timing by the registration roller pair 5 is carried on the transfer conveyance belt 60, conveyed toward the toner image forming units 1Y, 1M, 1C, and 1K, and passes through the transfer nips. .

  The toner images developed on the toner drums 11Y, 11M, 11C, and 11K of the toner image forming units 1Y, 1M, 1C, and 1K are superimposed on the transfer paper 100 at the transfer nips, respectively. It is transferred onto the transfer paper 100 under the action of pressure. By this superposition transfer, a full color toner image (full color toner image) is formed on the transfer paper 100.

  The surfaces of the photosensitive drums 11Y, 11M, 11C, and 11K after the toner image transfer are cleaned by a cleaning device, and are further discharged to prepare for the formation of the next electrostatic latent image.

  On the other hand, the transfer paper 100 on which the full-color toner image is formed is fixed in the first paper discharge direction B or the second in accordance with the rotation posture of the switching guide G after the full-color toner image is fixed by the fixing unit 7. In the paper discharge direction C. When the paper is discharged from the first paper discharge direction B onto the paper discharge tray 8, it is stacked in a so-called face-down state with the image surface down. On the other hand, when the paper is discharged in the second paper discharge direction C, it is conveyed toward another post-processing device (not shown) (such as a sorter or a binding device) or again for double-sided printing via a switchback unit. It is conveyed to the registration roller pair 5.

  In the developing device of this embodiment, for example, as shown in FIG. 2, the developing device 40Y has a developing roller 42Y disposed so as to be partially exposed from the opening of the casing. Further, it also includes a first conveying screw 43Y, a second conveying screw 44Y, a regulating blade 45Y, a toner concentration sensor (hereinafter referred to as T sensor) 46Y, and the like.

  A two-component developer 49Y containing a magnetic carrier and negatively chargeable Y toner is accommodated in the casing. The two-component developer 49Y is frictionally charged while being agitated and conveyed by the first conveying screw 43Y and the second conveying screw 44Y, and then carried on the surface of the developing roller 42Y. Then, after the layer thickness is regulated by the regulating blade 45Y, the layer is conveyed to the developing area facing the photoreceptor 2Y, where Y toner is attached to the electrostatic latent image on the photoreceptor 2Y. This adhesion forms a Y toner image on the photoreceptor 2Y. The two-component developer that has consumed Y toner by development is returned to the casing as the developing roller 42Y rotates.

  A partition wall 47Y is provided between the first transport screw 43Y and the second transport screw 44Y. The partition wall 47Y separates the first supply unit that accommodates the developing roller 42Y, the first conveyance screw 43Y, and the like and the second supply unit that accommodates the second conveyance screw 44Y in the casing. The first conveying screw 43Y is rotationally driven by a driving unit (not shown), and supplies the two-component developer in the first supply unit to the developing roller 42Y while conveying the two-component developer from the front side to the back side in the drawing. The two-component developer conveyed to the vicinity of the end of the first supply unit by the first conveyance screw 43Y enters the second supply unit through an opening (not shown) provided in the partition wall 47Y. In the second supply unit, the second transport screw 44Y is rotationally driven by a drive unit (not shown), and transports the two-component developer sent from the first supply unit in the opposite direction to the first transport screw 43Y. The two-component developer transported to the vicinity of the end of the second supply unit by the second transport screw 44Y returns to the first supply unit through the other opening (not shown) provided in the partition wall 47Y. .

  The T sensor 46Y including a magnetic permeability sensor is provided on the bottom wall near the center of the second supply unit, and outputs a voltage having a value corresponding to the magnetic permeability of the two-component developer passing therethrough. Since the magnetic permeability of the two-component developer shows a certain correlation with the toner density, the T sensor 46Y outputs a voltage having a value corresponding to the Y toner density. This output voltage value is sent to a control unit (not shown). This control unit includes a RAM, in which Y Vtref, which is a target value of the output voltage from the T sensor 46Y, is stored. In addition, data of M Vtref, C Vtref, and K Vtref, which are target values of the output voltage from the T sensor as indicated by 46Y in FIG. 2 mounted in another developing device, is also stored. The Y Vtref is used for driving control of a Y toner conveying device (not shown). Specifically, the control unit drives and controls a Y toner conveying device (not shown) so that the value of the output voltage from the T sensor 46Y approaches the V Vref for Y, and replenishes Y toner in the second supply unit 49Y. Let By this replenishment, the Y toner concentration of the two-component developer in the developing device 40Y is maintained within a predetermined range. Similar toner replenishment control is performed for the developing devices of the other process cartridges.

  Next, the characteristic part in the developing device of this embodiment will be described.

  FIG. 3 is a diagram in which a developer layer thickness regulating shape 50Y is provided at a position in contact with the developer moving on the developer carrier above the first stirring means 43Y that is a characteristic part of the present embodiment. It is.

  As shown in FIGS. 4 and 5, in the state where the regulating member 50Y is not provided, the height of the developer surface becomes uneven due to the conveying screw pitch, resulting in significant undulations. Therefore, the amount of the developer carried and moved on the developer carrying member is affected by the portion where the screw of the first conveying screw 43Y is present and the portion where the screw is not present, and the developer layer thickness on the developer carrying member is uneven. It will occur.

  However, as shown in FIGS. 3, 6, and 7, by providing the developer layer thickness regulating shape 50 </ b> Y, the agent surface itself is raised, so that it is not easily affected by the screw. Further, even if the developer is influenced by the screw, the developer carried on the developer carrier and the developer layer thickness regulating member are in contact with each other at the closest portion 50aY of the developer layer thickness regulating member with the developer carrier. Thus, the developer layer thickness unevenness (screw pitch unevenness) can be leveled by the layer thickness regulating shape 50Y.

  The developer layer thickness regulating shape 50Y is attached to the partition wall 47Y of the developing case with double-sided tape. Accordingly, it is possible to arbitrarily select a shape that optimizes the GAP at the closest portion with the developer carrier of the regulating member depending on the amount of the developer.

  8 to 9 show configuration examples of stirring means (conveying screws) 43Y and 44Y which are characteristic portions of the present embodiment. As shown in these drawings, the shaft diameter of the central portion of the first conveying screw 43Y is thicker than the shaft diameters of both end portions.

  In the present embodiment, by providing the developer layer thickness regulating shape 50Y, the developer passes through the re-adjacent portion 50aY, so that the agent pressure in the vicinity increases. When the agent pressure increases, the central portion in the longitudinal direction of the first conveying screw 43Y tends to bend, and the unevenness of the agent surface increases when rotating in that state, by thickening the central portion of the shaft of the first conveying screw 43Y, By increasing the strength, the shaft does not bend to reduce the shake, and the adverse effect on the pumping of the developer is reduced.

  Next, as shown in FIGS. 10 to 11, in order to increase the strength of the central portion of the first conveying screw 43 </ b> Y, the central portion has a thick shaft diameter, and both end portions have thin shaft diameters. The part was tied with a taper. As a result, there is no step between the thick portion and the thin portion of the shaft of the first conveying screw 43Y, so that the flow of the developer that may stagnate at the step portion becomes smooth, and the occurrence of abnormal images can be suppressed. .

  A developing device that develops a latent image using a developer, having a regulating member that regulates the amount of developer on the developer carrier above the developer carrier, and transporting the developer while stirring. And a developing device having a partition wall between the first and second stirring means, the second stirring means provided on the opposite side of the developer carrier relative to the first stirring means, and the first stirring means. A developer layer thickness regulating shape is attached to the partition wall at a position in contact with the developer moving on the developer carrier above the first stirring means, and a central portion of the first transport means Since the shaft is not thicker than the shaft diameters at both ends thereof to increase the strength, the shaft is not bent and the vibration is improved, and the adverse effect on the pumping up of the developer at the central portion in the longitudinal direction is reduced. At the same time, it is possible to provide a highly reliable developing device that does not generate an image of uneven development pitch due to the effect of smoothing the developer pumping failure (pitch unevenness) by the conveying stirring means by the restricting member and the stirring of the developer by the restricting portion. (Claims 1 to 3)

  Since the portion having a thick shaft diameter at the center of the first stirring means and the portion having a thin shaft diameter at both ends are tapered, the step portion between the thick portion and the thin portion of the shaft of the first conveying screw 43Y is formed. Therefore, the flow of the developer considered to be stagnant at the stepped portion becomes smooth, and it is possible to suppress the occurrence of an abnormal image. (Claim 4)

  The developing device according to claim 5 is the developing device according to claims 1 to 4, wherein the developer is a two-component developer composed of toner and magnetic particles, and the particle size of the magnetic particles is 20 μm or more and 50 μm or less. It is characterized by that.

  By reducing the carrier particle size, an image with more excellent dot reproducibility can be formed. Specifically, the carrier particle size is desirably 20 μm or more and 50 μm or less. By setting the carrier particle size smaller than that of the conventional one and further setting the particle size in such a range, it is possible to uniformly reduce the thickness of the developer spike (carrier chain) at the time of image formation. Therefore, it is possible to deliver a more precise toner.

  In addition, since the density of developer spikes per unit area on the developing sleeve is increased, toner can be delivered to the latent image on the photoreceptor without any gap. Thereby, an image with more excellent dot reproducibility can be formed. If the carrier particle diameter is too larger than 50 μm, the total surface area of the carrier is reduced and the amount of toner held is reduced when compared with the same carrier amount. For this reason, the toner density is lowered. Although it is possible to increase the pumping amount to maintain the developing ability, toner sticking is likely to occur. On the other hand, if the carrier particle diameter is too smaller than 20 μm, the magnetic force holding force by the mag roller is reduced, causing carrier scattering and increasing carrier adhesion to the photoconductor, so 20 μm or more is desirable. However, if the dot reproducibility becomes high or the image quality becomes high, there is a risk that the reproducibility of development unevenness and the like also becomes high. By using this embodiment, it is possible not only to provide an image with excellent dot reproducibility by reducing the particle size of the carrier, but also to provide a developing device with little development unevenness.

  Further, the invention of claim 5 is the developing device according to claims 1 to 4, wherein the magnetic particles are obtained by coating a core material of a magnetic material with a resin coat film, and the resin coat film is made of a thermoplastic resin. What contains the resin component which bridge | crosslinked melanin resin, and a charge control agent is used, It is characterized by the above-mentioned.

  Specifically, it is desirable to use a coat film having elasticity and strong adhesive force, which is coated with a coat film containing particles having a diameter larger than the film thickness on the surface. FIG. 12 is an explanatory diagram of the carrier 500. Ferrite 501 is used as the core material of the carrier 500. The surface of the ferrite 501 is coated with a coating film 502 containing a charge adjusting agent in a resin component obtained by crosslinking a thermoplastic resin such as acrylic and a melamine resin. The coat film 502 has elasticity and strong adhesive force. Further, particles having a diameter larger than the film thickness of the coat film 502, for example, alumina particles 503 are dispersed on the surface. The alumina particles 503 are held with a strong adhesive force of the coating film 502.

  While the conventional carrier is configured based on the idea of obtaining a long life while gradually scraping a hard coat film, the carrier 500 shown in FIG. 12 absorbs an impact because the coat film 502 has elasticity. To suppress film scraping. Further, by dispersing alumina particles 503 having a diameter larger than the film thickness on the surface of the carrier 501, it is possible to prevent the impact on the coat film 502 and to clean the spent material. As described above, since the coating film can be prevented from being scraped and spent, it is possible to achieve a longer life than conventional carriers. Accordingly, it is possible to expect stabilization of the developer pumping amount, that is, stabilization of quality over a long period of time. By extending the service life, not only the user maintenance is reduced, but also the manufacturing manufacturer is meaningful in terms of cost.

  The developing device according to claim 6 is the developing device according to any one of claims 1 to 5, wherein the toner contains at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent. It is a toner obtained by subjecting a toner material liquid dispersed therein to at least one of a crosslinking reaction or an extension reaction in an aqueous medium.

  The toner suitably used in the image forming apparatus of the present embodiment includes a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a release agent are dispersed in an organic solvent. A toner obtained by crosslinking and / or elongation reaction in an aqueous solvent. Hereinafter, the constituent material and the manufacturing method of the toner will be described.

(polyester)
The polyester is obtained by a polycondensation reaction between a polyhydric alcohol compound and a polycarboxylic acid compound.

  Examples of the polyhydric alcohol compound (PO) include dihydric alcohol (DIO) and trihydric or higher polyhydric alcohol (TO). (DIO) alone or a mixture of (DIO) and a small amount of (TO) preferable. Examples of the dihydric alcohol (DIO) include alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol) , Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol) F, bisphenol S, etc.); alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the above alicyclic diol; Alkylene oxide bisphenol (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts. Among them, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use. The trihydric or higher polyhydric alcohol (TO) includes 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (Trisphenol PA, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols.

  Examples of the polyvalent carboxylic acid (PC) include divalent carboxylic acid (DIC) and trivalent or higher polyvalent carboxylic acid (TC). (DIC) alone and (DIC) with a small amount of (TC) Mixtures are preferred.

  Divalent carboxylic acids (DIC) include alkylene dicarboxylic acids (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid) And naphthalenedicarboxylic acid). Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. Examples of the trivalent or higher polyvalent carboxylic acid (TC) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid). In addition, as polyhydric carboxylic acid (PC), you may make it react with polyhydric alcohol (PO) using the above-mentioned acid anhydride or lower alkyl ester (Methyl ester, ethyl ester, isopropyl ester, etc.).

  The ratio of the polyhydric alcohol (PO) to the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Is 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.

  The polycondensation reaction between a polyhydric alcohol (PO) and a polycarboxylic acid (PC) is carried out in the presence of a known esterification catalyst such as tetrabutoxytitanate or dibutyltin oxide, and heated to 150 to 280 ° C. while reducing the pressure as necessary. The produced water is distilled off to obtain a polyester having a hydroxyl group. The hydroxyl value of the polyester is preferably 5 or more, and the acid value of the polyester is usually 1 to 30, preferably 5 to 20. By giving an acid value, the toner tends to be negatively charged, and further, when fixing to a recording paper, the affinity between the recording paper and the toner is good and the low-temperature fixability is improved. However, when the acid value exceeds 30, there is a tendency to deteriorate with respect to the stability of charging, particularly environmental fluctuation.

  The weight average molecular weight is 10,000 to 400,000, preferably 20,000 to 200,000. A weight average molecular weight of less than 10,000 is not preferable because offset resistance deteriorates. On the other hand, if it exceeds 400,000, the low-temperature fixability is deteriorated.

  In addition to the unmodified polyester obtained by the above polycondensation reaction, the polyester preferably contains a urea-modified polyester. The urea-modified polyester is obtained by reacting a terminal carboxyl group or hydroxyl group of the polyester obtained by the above polycondensation reaction with a polyvalent isocyanate compound (PIC) to obtain a polyester prepolymer (A) having an isocyanate group. It is obtained by cross-linking and / or extending the molecular chain by the reaction of the amine with amines.

  Examples of the polyvalent isocyanate compound (PIC) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.) Aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanates; Those blocked with caprolactam or the like; and combinations of two or more of these.

  The ratio of the polyvalent isocyanate compound (PIC) is usually 5/1 to 1/1, preferably as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 4/1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. When the molar ratio of [NCO] is less than 1, when a urea-modified polyester is used, the urea content in the ester is lowered and hot offset resistance is deteriorated.

  The content of the polyvalent isocyanate compound (PIC) component in the polyester prepolymer (A) having an isocyanate group is usually 0.5 to 40 wt%, preferably 1 to 30 wt%, more preferably 2 to 20 wt%. . If it is less than 0.5 wt%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40 wt%, the low-temperature fixability deteriorates.

  The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2 on average. Five. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

  Next, as amines (B) to be reacted with the polyester prepolymer (A), a divalent amine compound (B1), a trivalent or higher polyvalent amine compound (B2), an amino alcohol (B3), an amino mercaptan (B4) ), Amino acid (B5), and amino acid block of B1 to B5 (B6).

  Examples of the divalent amine compound (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′-dimethyldicyclohexyl). Methane, diamine cyclohexane, isophorone diamine, etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like. Examples of the trivalent or higher polyvalent amine compound (B2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Examples of the compound (B6) obtained by blocking the amino group of B1 to B5 include ketimine compounds and oxazolidine compounds obtained from the amines of B1 to B5 and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines (B), preferred are B1 and a mixture of B1 and a small amount of B2.

  The ratio of amines (B) is equivalent to the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the polyester prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). Is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. When [NCO] / [NHx] is more than 2 or less than 1/2, the molecular weight of the urea-modified polyester is lowered, and the hot offset resistance is deteriorated.

  The urea-modified polyester may contain a urethane bond together with a urea bond. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.

  The urea-modified polyester is produced by a one-shot method or the like. Polyhydric alcohol (PO) and polyvalent carboxylic acid (PC) are heated to 150-280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate, dibutyltin oxide, etc., and water generated while reducing the pressure as necessary. Distill off to obtain a polyester having a hydroxyl group. Subsequently, at 40-140 degreeC, this is made to react with polyvalent isocyanate (PIC), and the polyester prepolymer (A) which has an isocyanate group is obtained. Further, this (A) is reacted with amines (B) at 0 to 140 ° C. to obtain a urea-modified polyester.

  When reacting (PIC) and when reacting (A) and (B), a solvent may be used if necessary. Usable solvents include aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (dimethylformamide, dimethylacetamide, etc.) and ethers And those inert to isocyanates (PIC), such as tetrahydrofuran (such as tetrahydrofuran).

  In addition, in the crosslinking and / or extension reaction between the polyester prepolymer (A) and the amines (B), a reaction terminator can be used as necessary to adjust the molecular weight of the resulting urea-modified polyester. Examples of the reaction terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).

  The weight average molecular weight of the urea-modified polyester is usually 10,000 or more, preferably 20,000 to 10,000,000, and more preferably 30,000 to 1,000,000. If it is less than 10,000, the hot offset resistance deteriorates. The number average molecular weight of the urea-modified polyester or the like is not particularly limited when the above-mentioned unmodified polyester is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. When the urea-modified polyester is used alone, its number average molecular weight is usually 2000-15000, preferably 2000-10000, more preferably 2000-8000. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color apparatus are deteriorated.

  By using the unmodified polyester and the urea-modified polyester in combination, the low-temperature fixability and the gloss when used in the full-color image forming apparatus 100 are improved. Therefore, it is preferable to use the urea-modified polyester alone. The unmodified polyester may include a polyester modified with a chemical bond other than a urea bond.

  The unmodified polyester and the urea-modified polyester are preferably at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Therefore, it is preferable that the unmodified polyester and the urea-modified polyester have a similar composition.

  The weight ratio of unmodified polyester to urea-modified polyester is usually 20/80 to 95/5, preferably 70/30 to 95/5, more preferably 75/25 to 95/5, and particularly preferably 80 /. 20-93 / 7. When the weight ratio of the urea-modified polyester is less than 5%, the hot offset resistance is deteriorated, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

  The glass transition point (Tg) of the binder resin containing unmodified polyester and urea-modified polyester is usually 45 to 65 ° C, preferably 45 to 60 ° C. If it is less than 45 ° C., the heat resistance of the toner deteriorates, and if it exceeds 65 ° C., the low-temperature fixability becomes insufficient.

  In addition, since the urea-modified polyester is likely to be present on the surface of the obtained toner base particles, the heat-resistant storage stability tends to be good even when the glass transition point is low as compared with known polyester-based toners.

(Coloring agent)
As the colorant, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher , Yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Vulcan fast yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Dan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Phi Sayred, Parachlor Ortonito Aniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmin Min BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R , Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thio Indigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red Polyazo Red, Chrome Vermillion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), indigo, ultramarine, bitumen, anthraquinone blue, fast violet B, methyl violet, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, Pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Phthalo Cyanine green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used. The content of the colorant is usually 1 to 15% by weight, preferably 3 to 10% by weight, based on the toner.

  The colorant can also be used as a master batch combined with a resin. As a binder resin to be kneaded together with the production of the master batch or the master batch, a polymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyl toluene or the like, or a copolymer of these and a vinyl compound, Polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, fat Aromatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like can be mentioned, and these can be used alone or in combination.

(Charge control agent)
Known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified 4 Secondary ammonium salts or compounds, tungsten simple substances or compounds, fluorine activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives. Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) Manufactured), copper phthalocyanine, perylene, quinacridone, azo series Fee, a sulfonic acid group, a carboxyl group, and polymer compounds having a functional group such as quaternary ammonium salts. Of these, substances that control the negative polarity of the toner are particularly preferably used.

  The amount of charge control agent used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is not uniquely limited. Preferably, it is used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the developer fluidity is lowered, and the image density is lowered. Invite.

(Release agent)
As a release agent, a low melting point wax having a melting point of 50 to 120 ° C. works more effectively as a release agent in the dispersion with the binder resin between the fixing roller and the toner interface. The effect on high temperature offset is exhibited without applying a release agent such as oil. Examples of such a wax component include the following. Examples of waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax, and rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, and paraffin, microcrystalline, And petroleum waxes such as petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, and synthetic waxes such as esters, ketones, and ethers can be used. Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon, and low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n- A crystalline polymer having a long alkyl group in the side chain such as a homopolymer or copolymer of polyacrylate such as lauryl methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.) can also be used. .

  The charge control agent and the release agent can be melt-kneaded together with the master batch and the binder resin, and of course, they may be added when dissolved and dispersed in the organic solvent.

(External additive)
Inorganic fine particles are preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles. The primary particle diameter of the inorganic fine particles is preferably 5 × 10 ⁻³ to ² μm, and particularly preferably 5 × 10 ⁻³ to ^0.5 μm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The use ratio of the inorganic fine particles is preferably 0.01 to 5 wt% of the toner, and particularly preferably 0.01 to 2.0 wt%.

Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Among these, as the fluidity imparting agent, it is preferable to use hydrophobic silica fine particles and hydrophobic titanium oxide fine particles in combination. In particular, when agitation and mixing are performed using an average particle diameter of both fine particles of 5 × 10 ⁻² μm or less, the electrostatic force and van der Waals force with the toner are remarkably improved. Even when stirring and mixing inside the developing device is performed to obtain a good image quality that does not cause the release of the fluidity imparting agent from the toner and does not generate firefly, etc., and further reduces the residual toner. It is done.

  Titanium oxide fine particles are excellent in environmental stability and image density stability, but have a tendency to deteriorate the charge rise characteristics. Therefore, if the amount of titanium oxide fine particles added is larger than the amount of silica fine particles added, this side effect is affected. It can be considered large. However, when the added amount of the hydrophobic silica fine particles and the hydrophobic titanium oxide fine particles is in the range of 0.3 to 1.5 wt%, the charge rising characteristics are not greatly impaired, and the desired charge rising characteristics can be obtained, that is, repeated copying. Stable image quality can be obtained even if

  Next, a toner manufacturing method will be described. Here, although a preferable manufacturing method is shown, it is not limited to this.

(Toner production method)
(1) A toner material solution is prepared by dispersing a colorant, unmodified polyester, a polyester prepolymer having an isocyanate group, and a release agent in an organic solvent.

  The organic solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal after toner base particle formation. Specifically, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, Methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform, and carbon tetrachloride are preferable. The usage-amount of an organic solvent is 0-300 weight part normally with respect to 100 weight part of polyester prepolymers, Preferably it is 0-100 weight part, More preferably, it is 25-70 weight part.

(2) The toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles.
The aqueous medium may be water alone or an organic solvent such as alcohol (methanol, isopropyl alcohol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.). It may be included.

  The amount of the aqueous medium used relative to 100 parts by weight of the toner material liquid is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight. If the amount is less than 50 parts by weight, the dispersion state of the toner material liquid is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 20000 parts by weight, it is not economical.

  Further, in order to improve the dispersion in the aqueous medium, a dispersant such as a surfactant and resin fine particles is appropriately added.

  As surfactants, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt, benzethonium chloride, fatty acid amide derivative, polyhydric alcohol Nonionic surfactants such as derivatives, for example, amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine And the like.

Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Examples of the anionic surfactant having a fluoroalkyl group that is preferably used include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [ω-fluoroalkyl (C _6- C ₁₁ ) oxy] -1-alkyl (C ₃ -C ₄ ) sodium sulfonate, 3- [ω-fluoroalkanoyl (C ₆ -C ₈ ) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C ₁₁ ~C ₂₀₎ carboxylic acids and metal salts thereof, perfluoroalkyl carboxylic acids (C ₇ ~C ₁₃₎ and metal salts thereof, perfluoroalkyl (C ₄ ~C ₁₂₎ sulfonic acids and metal salts thereof, perfluorooctane Sulfonic acid diethanolamide, N-propyl-N- (2-hydroxyethyl) perfluoroo Tan sulfonamide, perfluoroalkyl (C ₆ ~C ₁₀₎ sulfonamide propyl trimethyl ammonium salts, perfluoroalkyl (C ₆ ~C ₁₀₎ -N- ethylsulfonyl glycine salts, monoperfluoroalkyl (C ₆ ~C ₁₆₎ Examples thereof include ethyl phosphate.

  Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. DS-102 (manufactured by Daikin Industries, Ltd.), Megafac F-110, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink, Inc.), Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F150 (manufactured by Neos).

In addition, examples of the cationic surfactant include aliphatic 4 such as aliphatic primary, secondary or secondary amine acid and perfluoroalkyl (C ₆ -C ₁₀ ) sulfonamidopropyltrimethylammonium salt which are right on the fluoroalkyl group. Class ammonium salt, benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-121 (manufactured by Asahi Glass), Florard FC-135 (manufactured by Sumitomo 3M), Unidyne DS-202 ( Daikin-E Industries Co., Ltd.), Mega-Fac F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products Co., Ltd.), Footgent F-300 (Neos Co., Ltd.), etc. .

  The resin fine particles are added to stabilize the toner base particles formed in the aqueous medium. For this reason, it is preferable to add so that the coverage existing on the surface of the toner base particles is in the range of 10 to 90%. For example, polymethyl methacrylate fine particles 1 μm and 3 μm, polystyrene fine particles 0.5 μm and 2 μm, poly (styrene-acrylonitrile) fine particles 1 μm, trade names are PB-200H (manufactured by Kao), SGP (manufactured by Soken), Techno Examples include polymer SB (manufactured by Sekisui Chemical Co., Ltd.), SGP-3G (manufactured by Sokensha), and micropearl (manufactured by Sekisui Fine Chemical Co., Ltd.)

  In addition, inorganic compound dispersants such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite can also be used.

  As a dispersant that can be used in combination with the above resin fine particles and inorganic compound dispersant, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Such as acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxy Propyl, acrylic acid-3-chloro-2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Luric acid esters, N-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or compounds containing vinyl alcohol and a carboxyl group Esters such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl Nitrogen compounds such as imidazole and ethyleneimine, or homopolymers or copolymers such as those having a heterocyclic ring thereof, polyoxyethylene, poly Xoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxy Polyoxyethylenes such as ethylene nonylphenyl ester, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. Among these, the high-speed shearing method is preferable in order to make the particle size of the dispersion 2 to 20 μm. When a high-speed shearing disperser is used, the rotational speed is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C.

  (3) At the same time as the preparation of the emulsion, the amines (B) are added to cause a reaction with the polyester prepolymer (A) having an isocyanate group.

  This reaction involves molecular chain crosslinking and / or elongation. The reaction time is selected depending on the reactivity of the isocyanate group structure of the polyester prepolymer (A) with the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24 hours. The reaction temperature is generally 0 to 150 ° C, preferably 40 to 98 ° C. Moreover, a well-known catalyst can be used as needed. Specific examples include dibutyltin laurate and dioctyltin laurate.

  (4) After completion of the reaction, the organic solvent is removed from the emulsified dispersion (reactant), washed and dried to obtain toner base particles.

  In order to remove the organic solvent, the temperature of the entire system is gradually raised in a laminar stirring state, and after giving strong stirring in a certain temperature range, the solvent base is removed to produce spindle-shaped toner base particles. . Further, when an acid such as calcium phosphate salt or an alkali-soluble material is used as the dispersion stabilizer, the calcium phosphate salt is dissolved from the toner base particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. Remove. It can also be removed by operations such as enzymatic degradation.

  (5) A charge control agent is injected into the toner base particles obtained above, and then inorganic fine particles such as silica fine particles and titanium oxide fine particles are externally added to obtain a toner.

  The injection of the charge control agent and the external addition of the inorganic fine particles are performed by a known method using a mixer or the like.

  Thereby, a toner having a small particle size and a sharp particle size distribution can be easily obtained. Furthermore, by giving strong agitation in the process of removing the organic solvent, the shape between the true spherical shape and the rugby ball shape can be controlled, and the surface morphology is also controlled between the smooth shape and the umeboshi shape. be able to.

  When the above method is used, a shape close to a sphere can be obtained as compared with the pulverized toner. Therefore, the granularity is improved, and a high-quality image without roughness can be obtained. In addition, it is easy to reduce the particle size, which is more effective for high image quality. On the other hand, since unevenness becomes obvious, a developing device with high image quality and less density unevenness can be provided by combining with this embodiment.

  The developing device according to claim 8 is the developing device according to claim 7, wherein the toner has a volume average particle diameter of 3 to 8 μm and a ratio between the volume average particle diameter (Dv) and the number average particle diameter (Dn). (Dv / Dn) is in the range of 1.00 to 1.40.

  In order to reproduce minute dots of 600 dpi or more, the toner preferably has a volume average particle diameter of 3 to 8 μm. The ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is preferably in the range of 1.00 to 1.40. The closer (Dv / Dn) is to 1.00, the sharper the particle size distribution. With such a toner having a small particle size and a narrow particle size distribution, the toner charge amount distribution is uniform, a high-quality image with little background fogging can be obtained, and the electrostatic transfer method has a high transfer rate. can do. By combining with this embodiment, a developing device with high image quality and less density unevenness can be provided.

  The developing device of claim 9 is the developing device of claim 7 or 8, wherein the toner has a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 180. It is characterized by being.

The toner shape factor SF-1 is preferably in the range of 100 to 180, and the shape factor SF-2 is preferably in the range of 100 to 180. 13 to 14 are diagrams schematically showing the shape of the toner in order to explain the shape factor SF-1 and the shape factor SF-2. The shape factor SF-1 indicates the ratio of the roundness of the toner shape and is represented by the following formula (1). This is a value obtained by dividing the square of the maximum length MXLNG of the shape formed by projecting the toner on a two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-1 = {(MXLNG) ² / AREA} × (100π / 4) (1)

  When the value of SF-1 is 100, the shape of the toner becomes a true sphere, and becomes larger as the value of SF-1 increases.

The shape factor SF-2 indicates the ratio of the unevenness of the toner shape, and is represented by the following formula (2). A value obtained by dividing the square of the perimeter PERI of the figure formed by projecting the toner on the two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-2 = {(PERI) ² / AREA} × (100π / 4) Expression (2)

  When the value of SF-2 is 100, there is no unevenness on the toner surface, and as the value of SF-2 increases, the unevenness of the toner surface becomes more prominent.

  Specifically, the shape factor is measured by taking a photograph of the toner with a scanning electron microscope (S-800: manufactured by Hitachi, Ltd.), introducing it into an image analyzer (LUSEX 3: manufactured by Nireco) and analyzing it. Calculated.

  When the shape of the toner is close to a spherical shape, the contact state between the toner and the toner or the toner and the photoconductor becomes a point contact, so that the adsorbing force between the toners becomes weak and the fluidity increases, and the toner and the photoconductor The attraction force becomes weaker and the transfer rate becomes higher. If either of the shape factors SF-1 and SF-2 exceeds 180, the transfer rate is lowered, which is not preferable. A high transfer rate means that the developed toner image is faithfully reproduced.

  That is, if there is development unevenness in the developed toner image, it is faithfully reproduced without blurring after transfer. For this reason, there is a risk that uneven development will become apparent. By combining with this embodiment, a developing device with high image quality and less uneven development can be provided.

  According to a tenth aspect of the present invention, in the developing device according to the first to ninth aspects, the toner has a substantially spherical shape, and the shape is defined by a major axis r1, a minor axis r2, and a thickness r3 (however, r1 ≧ r2 ≧ r3), the ratio (r2 / r1) of the major axis r1 to the minor axis r2 is in the range of 0.5 to 1.0, and the ratio of the thickness r3 to the minor axis r2 (r3 / R2) is in the range of 0.7 to 1.0.

  The shape of the toner suitably used in the image forming apparatus according to the present embodiment is a substantially spherical shape, and can be represented by the following shape rule.

  FIG. 15A is a diagram schematically illustrating the shape of the toner of the present embodiment. In FIG. 15A, when a substantially spherical toner is defined by a major axis r1, a minor axis r2, and a thickness r3 (where r1 ≧ r2 ≧ r3), the toner of the present embodiment has a major axis. And the minor axis ratio (r2 / r1) (see FIG. 15B) is 0.5 to 1.0, and the ratio between the thickness and the minor axis (r3 / r2) (see FIG. 15C) is It is preferable that it exists in the range of 0.7-1.0. When the ratio of the major axis to the minor axis (r2 / r1) is less than 0.5, the dot reproducibility and transfer efficiency are inferior because of being away from the true spherical shape, and high-quality image quality cannot be obtained. On the other hand, if the ratio of thickness to minor axis (r3 / r2) is less than 0.7, the shape is close to a flat shape, and a high transfer rate like a spherical toner cannot be obtained. In particular, when the ratio of the thickness to the minor axis (r3 / r2) is 1.0, the rotating body has a major axis as a rotation axis, and the fluidity of the toner can be improved.

  In addition, r1, r2, r3 can be measured by the following method, for example. That is, the toner is uniformly dispersed and adhered onto a smooth measurement surface, and 100 particles of the toner are magnified 500 times with a color laser microscope “VK-8500” (manufactured by Keyence Corporation) to obtain the 100 toners. The major axis r1 (μm), the minor axis r2 (μm), and the thickness r3 (μm) of the particles can be measured and obtained from their arithmetic average values. The effect of the combination with the present embodiment is the same as that of claims 7-9.

  In addition, the image forming apparatus of the present embodiment includes an image carrier that carries an electrostatic latent image, a charging device that charges the image carrier, a developer carried on the developer carrier, and opposed to the image carrier. And a developing device for developing the latent image on the image bearing member into a toner image by transporting it to a developing region, and a transfer residual toner remaining on the image bearing member after transferring the developed toner image to a transfer material In the image forming apparatus having the cleaning device for removing the above, the developing device described above is used as the developing device.

  Further, the process cartridge of this embodiment includes an image carrier that carries an electrostatic latent image, a charging device that charges the image carrier, and a developer that is carried on the developer carrier and faces the image carrier. A developing device that transports the toner image to a developing area and develops the latent image on the image carrier to form a toner image; and a transfer residual toner remaining on the image carrier after the developed toner image is transferred to a transfer material. In the image forming apparatus having the cleaning device to be removed, the image carrier and the device including at least the developing device selected from the developing device, the charging device, and the cleaning device are integrally supported, and the image forming device The process cartridge is detachable from the main body. The process cartridge according to this embodiment uses the above-described developing device.

  The developing means described above is integrally coupled as a process cartridge, and the process cartridge is configured to be detachable from a main body of an image forming apparatus such as a copying machine or a printer. An outline of the configuration example is shown in FIG. This comprises a charging means 105, a developing means 106, a photoconductor 107, and a cleaning means 108.

  In the image forming apparatus using the process cartridge of this embodiment, the photosensitive member is rotationally driven at a predetermined peripheral speed. In the rotation process, the photosensitive member is uniformly charged with a positive or negative predetermined potential on its peripheral surface by the charging unit, and then the image exposure light from the image exposure unit such as slit exposure or laser beam scanning exposure. The electrostatic latent images are sequentially formed on the peripheral surface of the photoreceptor, and the formed electrostatic latent images are then toner developed by the developing means, and the developed toner images are exposed from the paper feeding unit. The image is sequentially transferred by the transfer means to the transfer material fed in synchronization with the rotation of the photosensitive member between the transfer member and the transfer means. The transfer material that has received the image transfer is separated from the surface of the photosensitive member, introduced into the image fixing means, and fixed on the image, and printed out as a copy (copy). The surface of the photoconductor after the image transfer is cleaned by removing the transfer residual toner by a cleaning means, and after being further discharged, it is repeatedly used for image formation.

  A regulating member that regulates the amount of the developer on the developer carrier above the developer carrier, a first agitation unit that conveys the developer while agitating; and the first agitation unit In a developing device having a second agitating means provided on the opposite side of the developer carrying member and a partition wall between the first and second agitating means, the developer carrying is provided above the first agitating means. A developer layer thickness regulating shape is attached to the partition wall at a position in contact with the developer moving on the body, and the strength of the central axis of the first conveying means is stronger than the axial axes of the both ends. Since the shaft has a thick shaft diameter, the shaft does not bend and the vibration is improved, and the adverse effect on the pumping up of the developer in the central portion in the longitudinal direction is reduced. At the same time, the effect of smoothing the developer pumping failure (pitch unevenness) by the conveying agitating means with the regulating member and the highly reliable image forming apparatus or process cartridge that does not generate the development pitch unevenness image by strengthening the developer agitation at the regulating portion Can be provided.

It is sectional drawing which shows schematic structure of the laser printer to which the image development apparatus of this embodiment is applied. It is sectional drawing which shows the conventional developing device. It is sectional drawing of the image development apparatus which has the developer layer thickness control member of this embodiment. It is sectional drawing which shows a developer conveyance state when there is no developer layer thickness control member (conventional example). FIG. 7 is a cross-sectional view perpendicular to the transport direction of a developing device without a material layer thickness regulating member (conventional example). FIG. 6 is a cross-sectional view illustrating a developer conveyance state when the developer layer thickness regulating member of the present embodiment is provided. FIG. 3 is a cross-sectional view of a developing device having a developer layer thickness regulating member according to the present embodiment. It is a perspective view showing a toner conveying screw configuration used in the developing device of the present embodiment. FIG. 5 is a cross-sectional view of a toner conveying screw having a thick central shaft diameter used in the developing device of the present embodiment. FIG. 6 is a perspective view of a conveying screw that is used in the developing device of the present embodiment and has a thick central shaft diameter with a taper. It is sectional drawing of the conveyance screw which used the developing apparatus of this embodiment, and thickened the taper diameter of the center part. It is a cross-sectional view of the carrier particles used in the developing device of this embodiment. It is a schematic diagram for explaining the shape factor SF-1 showing the shape of the toner used in the developing device of the present embodiment. It is a schematic diagram for explanation of a shape factor SF-2 showing the shape of the toner used in the developing device of the present embodiment. It is a schematic diagram showing a circular shape of a circular toner used in the developing device of the present embodiment. It is a schematic block diagram which shows the structure of the process cartridge of this embodiment.

Explanation of symbols

1Y, 1M, 1C, 1K Toner image forming unit 2 Optical writing unit 3, 4 Paper feed cassette 5 Registration roller pair 6 Transfer unit 7 Fixing unit 8 Paper discharge tray 11Y, 11M, 11C, 11K Photosensitive drum 40Y Developing device 42Y Developing roller 43Y First conveying screw 44Y Second conveying screw 45Y Restricting blade 46Y Toner density sensor 47Y Partition wall 49Y Two-component developer 50Y Developer layer thickness regulating shape 50aY The closest developer developer thickness regulating member to the developer carrier Section 60 Transfer conveyor belt 100 Transfer paper 105 Charging means 106 Developing means 107 Photoconductor 108 Cleaning means 500 Carrier core material 501 Ferrite 502 Coat film 503 Alumina particles B First paper discharge direction C Second paper discharge direction G Switching guide

Claims (12)

A first agitating means for conveying the developer while agitating; a second agitating means provided on the opposite side of the developer carrier relative to the first agitating means; and the first and second agitating means. A developing device having a partition wall therebetween,
A developing device comprising a regulating member for regulating the amount of developer on the developer carrier above the developer carrier. A regulating member that regulates the amount of developer on the developer carrier above, a first agitating unit that conveys the developer while agitating; and a developer carrying member relative to the first agitating unit A developing device having a partition wall between the second stirring means provided on the opposite side and the first and second stirring means,
A developer layer thickness regulating shape is attached to the partition wall so as to come into contact with the developer moving on the developer carrier above the first agitating means, and the shaft at the center of the first conveying means Has a stronger strength than the shafts at both ends. A regulating member that regulates the amount of developer on the developer carrier above, a first agitating unit that conveys the developer while agitating; and a developer carrying member relative to the first agitating unit A developing device having a partition wall between the second stirring means provided on the opposite side and the first and second stirring means,
A developer layer thickness regulating shape is attached to the partition wall so as to come into contact with the developer moving on the developer carrier above the first agitating means, and the shaft at the center of the first conveying means A developing device characterized in that the diameter is larger than the shaft diameter at both ends.   The central portion of the first developer agitating means and both end portions are connected with a strength between the central portions or connected via a connecting member that connects with a taper. Item 4. The developing device according to Item 2 or 3.   The developing device according to claim 1, wherein a developer having a magnetic carrier particle size of 20 to 50 μm is used.   The magnetic carrier particles of the developer are obtained by coating a core material of a magnetic material with a resin coat film. The resin coat film includes a resin component obtained by crosslinking a thermoplastic resin and a melanin resin, a charge control agent, The developing device according to claim 1, further comprising:   The toner of the developer is prepared by crosslinking a toner material solution in which at least a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a release agent is dispersed in an organic solvent in an aqueous medium. The developing device according to claim 1, wherein the developing device is a toner obtained by performing at least one of elongation reactions.   The toner has a volume average particle diameter of 3 to 8 μm and a ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is in the range of 1.00 to 1.40. The developing device according to claim 7.   The developing device according to claim 7 or 8, wherein the toner has a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 180.   The toner has a substantially spherical shape, and the shape is defined by a major axis r1, a minor axis r2, and a thickness r3 (where r1 ≧ r2 ≧ r3), and the ratio between the major axis r1 and the minor axis r2. (R2 / r1) is in the range of 0.5 to 1.0, and the ratio (r3 / r2) of the thickness r3 to the minor axis r2 is in the range of 0.7 to 1.0. The developing device according to claim 7.   An image carrier that carries an electrostatic latent image, a charging device that charges the image carrier, and a developer that is carried on the developer carrier and conveyed to a development region facing the image carrier, and the image carrier An image forming apparatus comprising: a developing device that develops a latent image on the image to form a toner image; and a cleaning device that removes transfer residual toner remaining on the image carrier after the developed toner image is transferred to a transfer material. An image forming apparatus using the developing device according to claim 1 as the developing device.   An image carrier that carries an electrostatic latent image, a charging device that charges the image carrier, and a developer that is carried on the developer carrier and conveyed to a development region facing the image carrier, and the image carrier An image forming apparatus comprising: a developing device that develops a latent image on the image to form a toner image; and a cleaning device that removes transfer residual toner remaining on the image carrier after the developed toner image is transferred to a transfer material. A process cartridge which integrally supports the image carrier and a device including at least the developing device selected from the developing device, the charging device, and the cleaning device, and is detachable from the main body of the image forming apparatus. A process cartridge, wherein the developing device is the developing device according to any one of claims 1 to 10.

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