JP2005070363A - Developing device and process cartridge using same, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively supply toner of stable and sufficient quantity to the surface of a toner carrier. <P>SOLUTION: A developing device is provided with a developing part 108, a toner storage part 104 for storing toner, a rotatable toner transport member 7 using an elastic sheet member 7a for transporting toner in the toner storing part 104 to the developing part 10, and an aperture part 200 connecting the developing part 108 and the toner storage part 104. When it is defined that a distance between the aperture upstream end part α of the aperture part 200 in a toner transport direction and the center of a rotational axis of the toner transport member 7 is A, a distance between the aperture downstream end part β of the aperture part 200 in the toner transport direction and the center of the rotational axis of the toner transport member 7 is B and the length of the toner transport member 7 from the center of the rotational axis of the same up to the rotation edge of the same is C, the relation of B<A<C is satisfied and the center of the rotational axis of the toner transport member 7 is vertically below a straight line connecting the aperture upstream end part α and the aperture downstream end part β. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a developing device, a process cartridge, and an image forming apparatus used for electrophotographic image formation.

  Many copying machines, printers, facsimile machines, etc. use an electrophotographic image forming apparatus, but this image forming apparatus rotates a photosensitive drum 111 as an electrophotographic photosensitive member as shown in FIG. Then, a latent image is formed by selective exposure to this, and the latent image is developed with a developer (hereinafter referred to as “toner”) by the developing device 208 to be visualized, and the toner The image is recorded by transferring the image onto a transfer material 114.

  Here, a conventional developing device used in the electrophotographic image forming apparatus will be briefly described. FIG. 25 shows a developing device using magnetic one-component toner. The developing device 208 includes a developing unit 108 and a toner storage unit 104. A non-magnetic developing sleeve containing a fixed magnet 106 is supported in the developing unit 108 so as to be rotatable in the direction of arrow R2, and the toner sent from the toner storage unit 104 is attracted to the surface of the developing sleeve 105 by the magnetic force of the magnet 106. The latent image formed on the photoconductive drum 111 is supplied to the photoconductive drum 111 by applying an appropriate charge by frictional charging by rubbing between the elastic blades 107a contacting the surface of the developing sleeve 105. Is developed.

  Here, as shown in FIG. 25, the toner storage section 104 is provided with a stirring member 120 that can rotate in the direction of arrow R4, and the developing section 108 is provided with a stirring member 130 that can rotate in the direction of arrow R3. These stirring members 120 and 130 both have a rod-like member in a crank shape and rotate around both ends thereof. The rotation of the stirring members 120 and 130 prevents the toner from being sent out and loosened to increase the density of the toner (hereinafter referred to as “packing”).

  In addition, as the above-mentioned packing prevention configuration, there is also a configuration configured as shown in Japanese Patent Laid-Open No. 02-285374. This includes a toner storage unit that transports toner toward the developing unit through the opening between the developing unit and the developing unit while scooping up the toner by the developing unit and the agitator, and is substantially horizontal from the vicinity of the upper end of the opening. A coating unit is provided on the toner carrier in the developing unit to uniformly adhere the toner around the toner carrier onto the toner carrier, and a circulation guide member for toner is provided from the vicinity of the upper end of the opening to the coating unit. doing. As a result, even if the amount of toner consumed in the developing unit is smaller than the amount of toner transported from the toner storage unit, the packing in the developing unit is eliminated, the driving torque of the developing sleeve rotating at a constant speed increases, abnormal noise, chattering, etc. This prevents the occurrence of vibration.

Japanese Patent Laid-Open No. 02-285374

  However, in the image forming apparatus having the above-described configuration, the following problems are desired to be improved even in a developing apparatus including a toner conveying member and a toner carrier having excellent toner conveying characteristics and developing characteristics. It was a level.

  In other words, the toner conveying member has its shape and agitation speed set so that the toner can be efficiently conveyed to the developing unit. However, on the halftone image, vertical stripes and fading, and density tracking during continuous high printing. In some cases, this causes a problem of density unevenness on the image due to the nature of the image.

  As a result of examining the above points, it was found that density unevenness on the image due to vertical stripes and fading on the halftone image, density followability at the time of continuous high printing, etc. occurred by the following mechanism. .

  (1) Longitudinal streaks (hereinafter simply referred to as “vertical streaks”) generated on a halftone image are prominent in a high temperature environment. This is because the elastic sheet member of the toner conveying member rubs the inner wall in the toner accommodating portion in order to efficiently convey the toner from the toner accommodating portion to the developing portion.

  With the above configuration, the toner is sandwiched between the inner wall and the elastic sheet member in the toner storage portion, and is rubbed against the elastic sheet member and the inner wall over and over again. The liberation is promoted and the toner itself deteriorates. Particularly in a high temperature environment, the inside of the developing unit and the toner storage unit becomes high temperature, so that the toner easily deteriorates.

  Coarse particles are generated by the deterioration of the toner, and are conveyed to the developing unit by the circulation of the toner. Thereafter, the toner is taken into the toner carrier while circulating in the developing portion, and is clogged with the elastic blade member that regulates the toner. As a result, uniform coating of the toner on the toner carrying member is hindered, and toner coating unevenness occurs. After being developed as it is, it appears as a vertical stripe on the halftone image.

  (2) In addition, density unevenness on the image due to fading, density followability during continuous high printing, etc. (hereinafter referred to as “fading”) is caused by the amount of toner consumed in the developing unit being transported from the toner storage unit. The amount of toner is insufficient in the vicinity of the toner carrying member due to the amount exceeding the amount or insufficient toner conveying force. As a result, only a small amount of toner remaining in the developing unit is repeatedly circulated in the vicinity of the toner carrier, causing problems such as deterioration of the toner itself and density followability due to lack of toner. Produce.

  Conversely, if the amount of toner consumed in the developing unit is too small compared to the amount of toner transported from the toner storage unit, the state of the toner inside the developing unit is caused by the packing phenomenon caused by excessively transporting toner into the developing unit. As a result, the above-mentioned problems may occur as a result of the stagnation.

  When the toner packing phenomenon occurs in the developing device, not only does image unevenness such as fading occur, but an excessive load is applied to the motor that rotates the stirring member that stirs the toner, or the stirring member may become difficult to rotate. There is also a possibility to do.

  As described above, as a method for preventing vertical stripes and fading, a method of using the stirring member 130 in the developing unit 108 (hereinafter referred to as “stirring method”) as in the developing device shown in FIG. As shown in Japanese Laid-Open Patent Application No. 02-285374, a toner storage unit is disposed below the developing sleeve and a toner pumping type developing unit is used (hereinafter referred to as “pumping”). Method) ”.

  However, the agitation method requires a total of two agitation members in the developing unit and the toner storage unit, so there is a problem in terms of space and cost, and an increase in the amount of toner filling accompanying an increase in the life of the process cartridge. Taking the tendency into consideration, it is necessary to improve the stirring member in the developing section.

  In addition, the number of parts will increase when taking into account the increasing trend of process speed and toner filling amount due to the longer life of process cartridges in the future, or the compactness, space saving, and product cost reduction of image forming devices and cartridges. It is necessary to improve the toner conveying member itself in the developing container rather than making it happen.

  Accordingly, the present invention has been made to solve the above-described problems of the prior art, and the object of the present invention is to improve efficiency from the toner storage portion to the development portion through an opening connecting the development portion and the toner storage portion. It is an object of the present invention to provide a developing device, a process cartridge and an image forming apparatus using the same, which can effectively supply a stable and sufficient amount of toner onto a toner carrier by well transporting the toner.

  As a result, vertical streaks that occur on halftone images, fading and density followability during continuous high printing, etc., without causing problems such as toner deterioration and density followability due to toner shortage in the developing unit, etc. It is possible to suppress the occurrence of density unevenness on the image due to the above.

  The first means in the present invention has a magnetic field generating means that carries toner and is fixed inside, a developing unit having a rotatable toner carrier, a toner storage unit that stores the toner, In a developing device comprising a rotatable toner conveying member using an elastic sheet member that conveys the toner to the developing unit in a toner accommodating unit, and having an opening connecting the developing unit and the toner accommodating unit. The distance between the upstream end of the opening in the toner conveying direction and the rotation axis center of the toner conveying member is A, and the distance between the downstream end of the opening in the toner conveying direction and the rotation axis center of the toner conveying member at the opening is B. Where C is the length from the rotation axis center of the toner conveying member to the rotation tip of the toner conveying member, and B <A <C. It is characterized in that in a vertical below the straight line connecting the opening downstream end and the open upstream end.

  The second means has a magnetic field generating means which carries toner and is fixed inside, and a developing section provided with a rotatable toner carrier, a toner storage section for storing the toner, and an inside of the toner storage section A developing device having a rotatable toner conveying member using an elastic sheet member that conveys the toner to the developing unit, and having an opening connecting the developing unit and the toner storage unit. The toner comprises a stirring support member having a rotating shaft directed in the direction and an elastic sheet member formed in a plate shape and having a base end portion fixed to the stirring support member, with the gravity direction being a negative direction. The amount of displacement from the rotation axis center of the toner conveying member to the plane including the elastic sheet when the rotation tip of the elastic sheet member in the conveying member faces the opening side is X, and the amount of the toner conveying member When the amount of displacement of the horizontal plane including the open upstream end of the toner conveying direction is Y from guinea center of the opening, and having a relation of Y <X.

  According to a third means, in the second means, the distance between the upstream upstream end portion of the opening in the toner conveyance direction and the center of the rotation axis of the toner conveyance member is A, and the opening in the toner conveyance direction at the opening portion. The distance between the downstream end portion and the rotation axis center of the toner conveying member is B, and the length from the rotation axis center of the toner conveying member to the rotation tip of the toner conveying member is C, and B <A < Further, the rotation axis center of the toner conveying member is vertically below a line segment connecting the upstream end of the opening and the downstream end of the opening.

  The fourth means has a relation of Y <X <Y + Z in the third means, where Z is the distance between the horizontal plane including the opening upstream end and the horizontal plane including the opening downstream end. Features.

  The fifth means has a magnetic field generating means which carries toner and is fixed inside, and has a developing part provided with a rotatable toner carrier, a toner containing part for containing the toner, and an inside of the toner containing part A developing device having a rotatable toner conveying member using an elastic sheet member that conveys the toner to the developing unit, and having an opening connecting the developing unit and the toner storage unit. When rubbing the bottom shape of the toner storage portion, the pressure at one point in the longitudinal direction is 5 mN or more, and the pressure corresponding to the amount of change that becomes the maximum pressure in the toner storage portion is 130 mN or less. To do.

  According to a sixth means, in the fifth means, the toner conveying member is formed in a plate shape and has a base end portion fixed to the agitation support member. In the range from 1.5 mm to 5.5 mm in the short direction from the rotation tip of the elastic sheet member, the elastic sheet member is allowed to penetrate 1.5 mm in the short direction with respect to one point in the long direction. When the pressure at this time is P, the relationship is 5 mN ≦ P ≦ 130 mN.

  According to a seventh means, in the fifth means, the toner conveying member is formed in a plate shape and has a base end portion fixed to the agitation support member. In the range from 1.5 mm to 5.5 mm in the short direction from the rotation tip of the elastic sheet member, the elastic sheet member is allowed to penetrate 1.5 mm in the short direction with respect to one point in the long direction. When the pressure at that time is P, the relationship is 10 mN ≦ P ≦ 50 mN.

  According to an eighth means, in the fifth means, the distance between the upstream end of the opening in the toner transport direction in the opening and the rotational axis center of the toner transport member is A, and the opening in the toner transport direction in the opening is The distance between the downstream end portion and the rotation axis center of the toner conveying member is B, and the length from the rotation axis center of the toner conveying member to the rotation tip of the toner conveying member is C, and B <A < Further, the rotation axis center of the toner conveying member is vertically below a straight line connecting the upstream end of the opening and the downstream end of the opening.

  According to a ninth means, in any one of the first to eighth means, a charge control agent is externally added to the toner as an external additive, and a hydrophobic silica fine powder is used as the charge control agent. And is externally added in the range of 0.5 to 2.0 parts by weight with respect to 100 parts by weight of the binder resin.

  The tenth means is a development of any one of the first to ninth means as a process means acting on the electrophotographic photosensitive member and the electrophotographic photosensitive member in a process cartridge that is detachable from the main body of the image forming apparatus. And a device.

  An eleventh means is the image forming apparatus of the tenth means, further comprising a developing device for developing the electrostatic latent image formed on the electrophotographic photosensitive member with toner, wherein the electrophotographic photosensitive member and the developing device are provided. It has a characteristic.

  The twelfth means comprises an image forming apparatus including any one of the first to ninth developing devices for developing the electrostatic latent image formed on the electrophotographic photosensitive member with toner. .

  In the first means, the toner conveyance performance and the circulation state are increased with a cheaper and easier configuration than the conventional developing device, and the density unevenness on the image due to fading, density followability during continuous high printing, etc. It is possible to prevent the occurrence of this, and it is effective for the rise of the concentration in the initial state. As a result, a stable image can be obtained in the long term.

  In the second to fourth means, the toner conveyed by the toner conveying member is further supplied to the developing unit by its own weight, and the toner supply can be further stabilized.

  In the fifth to eighth means, when the toner is further conveyed to the developing unit by the toner conveying member, the toner is effectively prevented from deteriorating without developing a large pressure and developed. Can be used.

  In the ninth means, the toner supply stability can be further improved by using a predetermined toner.

  In the tenth to twelfth means, it is possible to provide a process cartridge and an image forming apparatus provided with a developing device capable of stably supplying toner to the developing unit.

  Next, a developing device according to an embodiment of the present invention will be described by exemplifying an electrophotographic image forming apparatus including the developing device.

[First Embodiment]
First, the overall configuration of the image forming apparatus including the developing device according to the first embodiment will be described, and then the configuration of the developing device will be described.

{Overall configuration of device}
FIG. 1 is an overall schematic explanatory diagram of an image forming apparatus. This image forming apparatus includes an image forming apparatus main body (hereinafter simply referred to as “apparatus main body”) 101 as a printer engine.

  Inside the apparatus main body 101, a drum-shaped electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) is provided as an image carrier. The photosensitive drum 111 has a photosensitive drum gear 211 (see FIG. 3) fixed to one end in the longitudinal direction (axial direction). The photosensitive drum 111 rotates at a predetermined process speed (circumferential speed) in the direction of the arrow R1 in FIG. 1 around the axis by transmitting driving force to the photosensitive drum gear 211 from driving means (not shown). Driven.

  The surface of the photosensitive drum 111 is charged by a charging roller 103 as a charging device. The charging roller 103 is disposed in contact with the surface of the photosensitive drum 111, and is driven to rotate as the photosensitive drum 111 rotates in the direction of arrow R1. For example, a charging bias in which an AC voltage and a DC voltage are superimposed is applied to the charging roller 103 by a charging bias application power source (not shown). As a result, the surface of the photosensitive drum 111 is uniformly charged to a predetermined polarity and a predetermined potential.

  An electrostatic latent image is formed by the exposure device 102 on the surface of the photosensitive drum 111 after charging. The exposure device 102 has a laser scanner, polygon mirror, reflection lens, etc. (not shown), irradiates the surface of the photosensitive drum 111 with laser light based on image information, removes the charge of the irradiated portion, and generates an electrostatic latent image. Is formed.

  The electrostatic latent image thus formed on the surface of the photosensitive drum 111 is developed as a toner image by being attached with toner by the developing device 8 according to the present invention. The developing device 8 will be described in detail later.

  The toner image formed on the surface of the photosensitive drum 111 is transferred onto the transfer material 114 by a transfer roller 110 as a transfer device. The transfer roller 110 is pressed against the surface of the photosensitive drum 111 to form a transfer nip portion, and is driven to rotate as the photosensitive drum 111 rotates. The transfer material 114 is nipped and conveyed by the transfer nip portion. This transfer material 114 is housed in a feed cassette 117 and supplied to the transfer nip portion in synchronization with the toner image on the photosensitive drum 111 by a feed roller 116, a registration roller (not shown), or the like. Simultaneously with the nipping and conveying of the transfer material 114, a transfer bias having a polarity opposite to that of the toner image on the photosensitive drum 111 is applied to the transfer roller 110 by a transfer bias applying power source (not shown). The toner image is transferred onto the transfer material 114.

  The toner remaining on the surface of the photosensitive drum 111 after the transfer of the toner image to the transfer material 114 is removed by the cleaning blade 113 of the cleaning device 112, and used for the next image formation.

  On the other hand, the transfer material 114 after transfer of the name toner image is conveyed to the fixing device 115 and is heated and pressurized to fix the toner image on the surface, and the transfer material 114 after fixing the toner image is external to the apparatus main body 101. The image formation is completed.

{Developer}
Next, the configuration of the developing device 8 for developing the latent image formed on the photosensitive drum 111 with toner will be described.

  FIG. 2 is a longitudinal sectional view of the developing device using the magnetic one-component toner according to the first embodiment. The developing unit 108 that stores toner therein and the developing unit 108 that supplies toner to the photosensitive drum 111 are illustrated. I have. The developing unit 108 has an opening 108a in a lower portion on the front side, and a developing sleeve 105 as a toner carrier is disposed therein. In the following description, the side (left side in FIG. 2) facing the photosensitive drum 111 in the developing device 8 is referred to as the front side, and the side far from the photosensitive drum 111 is referred to as the rear side (right side in FIG. 2). And

  The developing sleeve 105 is a non-magnetic sleeve formed of an aluminum or stainless steel pipe, and is supported by the developing unit 108 so as to be rotatable in the direction of the arrow R2. As shown in FIG. 3, rollers 209 are fixed to both ends of the developing sleeve 105 in the longitudinal direction (axial direction), and these rollers 209 are brought into contact with the photosensitive drum 111, whereby a photosensitive member is obtained. A predetermined gap (gap) is secured between the drum 111 and the surface.

  Further, a developing sleeve gear 212 is fixed to one end portion of the developing sleeve 105, and a driving force is transmitted to the developing sleeve gear 212 from the photosensitive drum gear 211, whereby the developing sleeve 105 is Driven by rotation. The surface of the developing sleeve 105 is processed to have an appropriate surface roughness so that a desired amount of toner can be carried and conveyed. A magnet 106 is disposed inside the developing sleeve 105.

  The magnet 106 is formed in a cylindrical shape, and a plurality of N and S poles are alternately formed in the circumferential direction. Unlike the rotation of the developing sleeve 105 in the direction of the arrow R2, the magnet 106 is fixedly disposed inside the developing sleeve 105.

  An elastic blade 107a as a toner regulating member is in contact with the surface of the developing sleeve 105 described above. The elastic blade 107a is formed in a plate shape by, for example, urethane rubber, silicone rubber or the like, and its base end portion is fixed to the support metal plate 107b, and its distal end portion is applied to the surface of the developing sleeve 105 with a predetermined pressure. It is elastically deformed by contact. The elastic blade 107a regulates the thick layer of the toner 109 attracted to the surface of the developing sleeve 105 by the magnetic force of the magnet 106 described above.

  The toner carried on the surface of the developing sleeve 105 is conveyed by the rotation of the developing sleeve 105 in the direction of the arrow R2, and the toner is frictionally charged between the toner and the developing sleeve 105 and the elastic blade when the layer thickness is regulated by the elastic blade 107a. Appropriate charges are imparted by frictional electrification due to rubbing between 107 a and further conveyed to a developing region facing the surface of the photosensitive drum 111. At this time, a developing bias in which alternating current and direct current are superimposed is applied to the developing blade 105 by an alternating current power source and a direct current power source. As a result, the toner on the developing sleeve 105 flies to the photosensitive drum 111 in the developing region and is electrostatically attached to the electrostatic latent image, and the electrostatic latent image is developed as a toner image.

  The toner conveying member 7 is disposed in the toner accommodating portion 104 as a feeding unit that loosens the toner in the toner accommodating portion 104 and conveys the toner to the developing portion 108. The toner conveying member 7 used in this embodiment has a shape as shown in FIG. 4 and is composed of an elastic sheet member 7a and a stirring support member 7b. The elastic sheet member 7a is made of polyphenylene sulfide (PPS). The base end portion is fixed to the backup portion 7c integrated with the stirring support member 7b. Then, both ends of the stirring support member 7b are rotated in the direction of arrow R4 in FIG. The driving force for rotating the toner conveying member 7 is generally used by, for example, dropping the developing sleeve gear 212 (see FIG. 3) to an appropriate rotation speed with a gear train.

  Here, an example of the constituent members of the developing device 8 in the present embodiment will be described with specific numerical values.

  The developing sleeve 105 is a nonmagnetic aluminum sleeve having a diameter of 12 mm. The surface of the developing sleeve 105 is coated with a resin layer containing conductive particles in order to carry the toner and apply tribo, and the surface roughness is usually JIS standard Ra so that the average is 0.4 to 3.5 μm. Is formed. In this embodiment, an average Ra of 1.6 μm is used.

  As the magnet 106, a four-pole magnet roll in which N poles and S poles are alternately arranged in the circumferential direction is used, and is fixedly arranged inside the developing sleeve 105.

  As the elastic blade 107a, a silicone rubber having a JIS standard hardness of about 65 ° has a contact force of about 200 mN / cm to 400 mN / cm (about 20 gf / cm to 40 gf / cm) (the length of the developing sleeve 105). Abutting load per cm in the direction).

As the toner, a negatively chargeable magnetic one-component toner is used. As components, 140 parts by weight of styrene n-butyl acrylate copolymer as binder resin, 80 parts by weight of magnetic particles, 2 parts of negative charge control agent of monoazo iron complex, and 3 parts of low molecular weight polypropylene as wax are added. Melt and knead with a twin screw extruder heated to ℃, coarsely pulverize the cooled kneaded product with a hammer mill, finely pulverize the coarsely pulverized product with a jet mill, and air-classify the resulting finely pulverized product, weight Obtain a classified product with an average of 6.8 μm. A toner having a mean particle size of 6.8 μm is mixed with 1.2 parts by weight of a hydrophobic silica fine powder using a Henschel mixer. And a thing with a weight average particle diameter of the range of 3.5-7 micrometers is used. Such toner, when used in the developing apparatus 8 configured as described above, the toner coat amount on the developing sleeve 105 becomes about ^{0.5mg / cm 2 ~2.0mg / cm 2} .

  In the developing device of the present embodiment, a hydrophobic silica fine powder is used as a charge control agent, and a developer externally added in a range of 0.5 to 2.0 parts by weight with respect to 100 parts by weight of the binder resin is used. It is preferable for stabilizing toner conveyance.

  Here, the weight average particle diameter of the toner will be described. A Coulter Counter TA-II type (manufactured by Coulter Inc.) is used as the measuring device, and a 1% NaCl aqueous solution is prepared using first grade sodium chloride as the electrolyte. As a measuring method, 0.1 to 0.5 ml of a surfactant is added as a dispersing agent to 100 to 150 ml of the above-described electrolytic solution, and 2 to 20 ml of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser, and the particle size distribution is measured by using the above-mentioned Coulter counter with a 100 μm aperture as the aperture and based on the number. Thereby, a weight average particle diameter is calculated | required.

For example, when the gap between the photosensitive drum 111 and the developing sleeve 105 is about 300 μm, the developing bias applied to the developing sleeve 105 is DC voltage: V _DC = −550 V, AC voltage: rectangular wave Vpp = 1500 V, A frequency of 2200 Hz is applied.

The surface of the photosensitive drum 111 was charged to the dark potential V _D = −650 V by the charging roller 103, and the potential of the exposed portion, that is, the bright portion potential V _L = −150 V was obtained by subsequent laser exposure. As a result, so-called reversal development was performed in which the above-described negatively chargeable toner was adhered to the portion of the surface of the photosensitive drum 111 where the bright portion potential V _L was present.

{Configuration of the opening}
Next, a configuration for conveying toner more efficiently from the toner storage unit to the development unit, which is a feature of the present embodiment, will be described.

  The main feature of the present embodiment is that the opening 200 and the toner conveying member 7 located at a place connecting the toner storage unit 104 and the developing unit 108 have a shape as shown in FIG.

  From FIG. 5, the distance A between the opening upstream end portion (hereinafter, simply referred to as “opening upstream end portion”) α of the opening 200 in the toner transport direction and the axial center O of the toner transport member 7 is the downstream of the opening in the toner transport direction. The distance C between the end (hereinafter simply referred to as “opening upstream end”) β and the axial center O of the toner conveying member 7 is longer than the distance A, and the length C of the toner conveying member 7 is longer than the distance A. That is, the relationship is B <A <C. Further, the axial center O of the toner conveying member 7 is assumed to be vertically below the straight line connecting the end portions α and β.

  In this embodiment, the magnet roller 106 has a peak at which the toner taking-in pole S2 into the developing sleeve 105 is between the ends α and β, the distance A = 18 mm, the distance B = 16.5 mm, and the toner conveying member length C =. 20 mm, which satisfies the above-described condition, B <A <C. Further, the axial center O of the toner conveying member 7 is arranged vertically below the line segment connecting the end portions α and β, that is, the plane including the opening 200, and the toner conveying member 7 is arranged at the bottom of the toner accommodating portion 104. This is a so-called toner pumping system in which the toner is pumped up while being rubbed and supplied to the developing unit 108 through the opening.

  With such a configuration, first, the toner is pumped toward the opening 200 after following the bottom shape of the toner storage unit 104. Then, the toner conveying member 7 is released when passing through the opening upstream end portion α while rubbing the bottom shape of the toner storage portion 104, and the toner is supplied into the developing portion 108 through the opening portion 200 as shown in FIG. Is done.

  Further, as shown in FIG. 7, the toner conveying member 7 rotates in the direction of the arrow, thereby contacting the end of the opening 200 at the opening downstream end β point. Then, the elastic sheet of the toner conveying member 7 is bent, and all of the conveyed toner T can be pushed into the developing unit 108.

  As an effect of this, as shown in FIG. 7, since the extension line of the magnetic force S2 pole of the magnet roller 106 is arranged at the center position of the opening 200, it is supplied to the developing unit 108. The toner can be taken in smoothly, and the toner circulation in the developing unit 108 is activated. As a result, the toner can be transported more efficiently from the toner storage unit 104 to the developing unit 108 once the toner transporting member 7 rotates, and problems such as deterioration of the toner itself and density follow-up caused by lack of toner can be obtained. Without occurrence, it becomes possible to prevent the occurrence of density unevenness on the image due to fading, density followability during continuous high printing, and the like, and it is also effective in increasing the density in the initial state.

  Further, as shown in FIG. 8, toner is taken in from the toner storage unit 104, circulates around the elastic blade 107a in the developing unit 108, and freely falls in the direction of gravity to return to the toner storage unit 104 (A in the figure). ) To the developing unit 108 (movement from A to B in the figure) and the state of being circulated again. This is a toner pumping-type developing device, which is caused by the opening 200 being disposed obliquely with respect to the horizontal line when the apparatus main body is installed, and the toner circulates as described above, causing aggregation. The effect of preventing the packing phenomenon is obtained.

  In addition, the creation of two circulations means that the toner charged by a small circulation in the developing unit returns to the toner storage unit and circulates a large amount, which is particularly effective for the charge imparting to the toner in the initial state. is there.

[Second Embodiment]
Next, a developing device according to the second embodiment will be described. Since the basic configuration of the developing device and the configuration of the image forming apparatus in which the developing device is used are the same as those in the first embodiment, members having the same functions as those in the first embodiment are denoted by the same reference numerals. Will be omitted, and only differences from the first embodiment will be described.

  FIG. 9 is a longitudinal sectional view of the developing device according to the second embodiment. Unlike the developing device of the first embodiment, the developing device of the present embodiment has the axial center of the toner conveying member 7 in the toner storage unit 104 disposed slightly above the opening.

  In the first embodiment described above, the center of the toner conveying member 7 is arranged such that the rotation radius of the toner conveying member 7 follows the bottom shape of the toner accommodating portion 104, and the toner is removed from the toner accommodating portion 104. Pumped up and supplied to the development unit. However, in this embodiment, the axis center of the toner conveying member 7 of the toner storage unit 104 is disposed slightly above and apart from the opening 200, and the weight of the toner in the toner storage unit 104 reaches the opening 200. It has a configuration that affects it. Therefore, although similar to the configuration of the conventional developing device, the relationship between the opening 200 between the developing unit 108 and the toner storage unit 104 and the axial center of the toner conveying member 7 is B <A as described above. By satisfying the relationship <C and the fact that the axial center exists vertically below the plane including the opening, the advantages described in the first embodiment can be obtained. Further, the toner conveyance performance and the circulation state are improved, and the toner stirring effect by the toner conveyance member is considered to be more advantageous than the conventional configuration.

[Third Embodiment]
Next, a developing device according to the third embodiment will be described. Since the basic configuration of the developing device and the configuration of the image forming apparatus in which the developing device is used are the same as those in the first embodiment, members having the same functions as those in the first embodiment are denoted by the same reference numerals. Will be omitted, and only differences from the first embodiment will be described.

  10 to 12 are longitudinal sectional explanatory views of the developing device according to the third embodiment. The developing device according to the present embodiment is an experiment on the relationship between the upper and lower end positions of the opening 200, the rotation center position of the toner conveying member 7 and the position of the sheet member in order to efficiently convey the toner from the toner storage portion to the developing portion. It is what I asked for.

  As shown in FIGS. 10 to 12, the position of the rotation axis center O of the toner conveying member is (1) between the horizontal plane including the opening upstream end α and the horizontal plane including the opening downstream end β, and (2) upstream of the opening. The case where it exists vertically below the horizontal plane including the end α and (3) above the horizontal plane including the opening upstream end α will be described including the results of experiments in each case.

  The toner conveying member 7 used in this embodiment has a sheet member 7a having a thickness of 38 μm made of polyphenylene phalloid (PPS), and the stirring support member 7b has a square shape with a cross section of 8 mm × 8 mm. Are integrally provided with a backup portion 7c having a cross section of 1 mm × 4.3 mm. The base end portion of the sheet member 7a is fixed to the backup portion 7c.

And as shown in Figure 10,
The amount of displacement from the stirring rotation shaft center O to the plane including the elastic sheet member 7a is X,
The amount of displacement from the stirring rotation axis O to the horizontal plane including the opening upstream end α is Y,
The distance between the opening upstream end α and the opening downstream end β is Z,
Let S be the vertical distance from the center of the stirring rotation axis to the bottom surface of the toner storage unit.

  The displacement amounts X and Y are defined as + in the direction opposite to the gravity direction (upward in the vertical direction) and-in the direction of gravity (downward in the vertical direction) with respect to the center of the stirring rotation axis.

  Further, in the magnet roller 106, the toner intake pole S2 to the developing sleeve 105 has a peak pole between the opening upstream end portion α and the opening downstream end portion β.

  (1) When the rotation axis center O is located between a horizontal plane including the opening upstream end α and a horizontal plane including the opening downstream end β

  Z = 8 mm, Y = −4 mm, S = 15 mm, the distance between the opening upstream end α and the rotation axis center O is 20 mm, the axis center O of the toner conveying member 7 is fixed at the above position, and the stirring support member 7b The amount of displacement X was changed by changing the size, and the state of toner conveyance into the developing portion was examined by correlation with the degree of fading.

  In the experiment method, 20 solid black images were passed continuously under high temperature and high humidity. As a result of the experiment, as shown in the table of FIG. 13 (a), the degree of fading was good in a range satisfying −4.0 mm <X. In FIG. 13, ◯, Δ, and x indicate that there is no problem at all, Δ is no problem for practical use, and x is noticeable on the image.

  (2) When the position of the rotation axis center O is below the horizontal plane including the opening upstream end α

  The configurations of the toner storage unit 104, the developing unit 108, and the toner conveying member 7 are the same as in the case of (1). In FIG. 11, the distance Z between the openings is 8 mm, Y is 4 mm, S is 15 mm, and the distance between α and O is 20 mm.

  Here, as in the case of (1), the shaft center O of the toner conveying member 7 is fixed at the above position, and the displacement X is changed by changing the size of the agitation support member. The state of toner transport into the developing section was examined by correlation with the degree of fading. As a result, as shown in the table of FIG. 13 (b), the degree of fading was good in a range satisfying 4.0 mm <X.

  (3) When the position of the rotational axis center O is above the horizontal plane including the opening upstream end α

  The configurations of the toner storage unit 104, the developing unit 108, and the toner conveying member 7 are the same as in the case of (1). In FIG. 12, the distance between the opening Z = 8 mm, Y = −12 mm, S = 15 mm, and the distance between the opening upstream end α and the rotation axis center O is 20 mm.

  Here, as in the case of (1), the shaft center O of the toner conveying member 7 is fixed at the above position, and the displacement X is changed by changing the size of the stirring support member 7b. Thus, the state of toner transport into the developing portion was examined by correlation with the degree of fading. As a result, as shown in the table of FIG. 13 (c), the degree of fading was good in a range satisfying −12.0 mm <X.

  Summarizing the results of (1) to (3) above, the amount of displacement X from the stirring rotation axis center O to the plane including the elastic sheet, and from the stirring rotation axis center O to the horizontal plane including the opening upstream end α. The relationship between the displacement amount Y and the presence or absence of image defects (fading) is as shown in FIG. That is, in FIG. 14, fading occurred under the shaded area conditions, and no image defect was observed in the white area. The straight line shown in the graph of FIG. 14 becomes X = -4 mm when Y = -4 mm. This means that the plane including the stirring sheet member 7a becomes horizontal at the opening upstream end portion α.

  That is, the toner is pumped up toward the opening 200 from the bottom shape of the toner storage unit 104. The toner conveying member 7 is released when passing through the opening upstream end portion α while rubbing the bottom shape of the toner storage portion 104 and is supplied into the developing portion 108 through the opening portion 200. This is shown in FIG. At this time, if the angle θ between the straight line connecting the backup portion 7c of the toner conveying member 7 and the sheet member 7a and the horizontal plane is larger than 0 ° (horizontal state) at the upstream end portion α of the opening, the toner is caused by its own weight. It becomes easy to move into the developing section. Therefore, by satisfying Y <X, the toner can be efficiently fed into the developing unit 108.

[Fourth Embodiment]
Next, a developing device according to the fourth embodiment will be described. Since the basic configuration of the developing device and the configuration of the image forming apparatus in which the developing device is used are the same as those in the first embodiment, members having the same functions as those in the first embodiment are denoted by the same reference numerals. Will be omitted, and only differences from the first embodiment will be described.

  In the present embodiment, as in the first embodiment described above, the opening 200 is inclined, and the positional relationship between the upper and lower ends of the opening 200 and the rotation axis center of the toner transport member 7 is described in the third embodiment. It is comprised similarly to a form.

  That is, the opening 200 of the present embodiment is similar to the first embodiment in that the magnet roller 106 has a peak of the toner intake pole S2 to the developing sleeve 105 between the opening upstream end α and the opening downstream end β. Thus, the distance A = 18 mm, the distance B = 16.5 mm, and the toner conveying member length C = 20 mm, and the relationship B <A <C is satisfied (see FIG. 5). In addition, the axial center O of the toner conveying member 7 is a straight line connecting the opening upstream end portion α and the opening downstream end portion β, that is, vertically below a plane including the opening portion 200. The toner pumps up the toner while rubbing the bottom shape of the toner storage unit 104 and supplies it to the developing unit through the opening.

  On the other hand, the positional relationship between the upper and lower ends of the opening 200 and the rotation axis center of the toner conveying member 7 is the displacement amount X from the stirring rotation axis center O to the plane including the elastic sheet member 7a, as in the third embodiment. FIG. 16 shows the result of examining the relationship between the amount of displacement from the stirring rotation axis O to the horizontal plane including the opening upstream end α and the presence or absence of image defects (fading). In FIG. 16, fading occurred under the shaded area conditions. It can also be seen that the area where no image defect occurs satisfies the displacement amount Y <X <Y + 8 mm. Further, when the distance Z between the horizontal plane including the upstream upstream end portion α and the horizontal plane including the downstream downstream end portion β of the opening 200 is changed to 12 mm, no image defect occurs in a region where the displacement amount Y <X <Y + 12 mm. It was.

  From the above experimental results, it is understood that the supply of toner into the developing unit 108 can be further stabilized by satisfying Y <X <Y + Z.

  The toner supply mechanism by making the opening 200 oblique in the present embodiment is the same as the operation described with reference to FIGS. 6 to 8 in the first embodiment.

  Further, regarding the condition of the displacement amount X: Y <X <Y + Z, Y <X is a necessary condition, as described in the third embodiment, as described in the third embodiment. If the angle θ formed between the straight line connecting 7c and the sheet member 7a and the horizontal plane is larger than 0 ° (horizontal state), the toner easily moves into the developing portion due to its own weight.

  However, if X is equal to or greater than Z + Y, the angle θ shown in FIG. 17 becomes too large, and the amount of toner pumped from the bottom of the toner storage unit 104 decreases, so X <Y + Z is a necessary condition. Therefore, if the configuration satisfying the condition of Y <X <Z + Y is adopted, the toner supply into the developing unit 108 can be further stabilized.

[Fifth Embodiment]
Next, a developing device according to a fifth embodiment will be described. In this embodiment, the basic configuration of the developing device and the basic configuration of the image forming apparatus in which the developing device is used are the same as those in the first embodiment. Therefore, the members having the same functions as those in the first embodiment are the same here. The description will be omitted with reference numerals, and only the parts different from the first embodiment will be described.

  FIG. 18 is an explanatory view showing the bending of the inner wall near the opening of the developing device and the elastic sheet member in the fifth embodiment. In this embodiment, when the rotary toner conveying member 7 rubs the bottom shape of the toner storage portion 104, the pressure at one point in the longitudinal direction is about 5 mN (about 0.5 gf) or more, and It is characterized in that the pressure corresponding to the amount of change that is the maximum pressure in the toner storage portion satisfies a range of about 130 mN (about 13.0 gf) or less.

  A simple configuration in which the toner conveying member 7 that satisfies the setting condition is provided in the toner storage unit 104, the developing unit 108, and the developing sleeve 105 suppresses toner deterioration that occurs on the inner wall of the developing unit 108, and aggregates coarse particles and the like. As a result, it is possible to reduce the generation of objects and to suppress the occurrence of vertical stripes on the halftone image as much as possible, and at the same time, the toner can be efficiently conveyed.

  Here, the “halftone image vertical stripe” will be described. The generation mechanism is as follows.

  According to experiments and observations by the inventors, the toner transport member 7 is used to efficiently transport toner from the toner storage unit 104 to the developing unit 108 and to reduce the size and space of the developing device. The elastic sheet member 7 a not only rotates while rubbing along the bottom shape of the toner storage portion 104, but also rubs the inner wall near the opening 200.

  With this configuration, as described above, the toner is sandwiched between the inner wall of the toner storage portion and the elastic sheet member. Then, the elastic sheet member that is rotated many times continues to be rubbed against the inner wall, and stress is applied to promote aggregation of the toners and liberation and embedding of the external additive, thereby deteriorating the toner itself. In particular, in a high temperature environment, the developing unit and the toner storage unit become hot, so that the physical property value of the toner itself is likely to change, and deterioration is more likely to be promoted.

  For example, the degree of toner aggregation is about 10-15% for fresh toner, whereas the degree of toner aggregation in a developing device that has reached the end of its life in a high-temperature, high-humidity environment is about 70-80%. Also rises. The degree of toner aggregation at this time was measured as follows.

  Measurement was performed using a powder tester P-100 (manufactured by Hosokawa Micron Corporation). Specifically, on the shaking table, three stages of sieves are set in the order of 250 μm, 150 μm, and 75 μm from the top, the vibration swing width is 0.6 mm, the vibration time is 10 seconds, and 5 g of toner is gently placed. Vibrate. After stopping vibration, measure the mass remaining on each sieve. And a, b, and c are defined as follows.

  a = (the amount of toner remaining on the upper screen) ÷ 5 (g) × 100

  b = (amount of toner remaining on the middle screen) ÷ 5 (g) × 100 × 0.6

  c = (amount of toner remaining on the lower screen) ÷ 5 (g) × 100 × 0.2

  The degree of aggregation (%) was calculated as a + b + c. The degree of aggregation was measured by measuring the degree of toner aggregation before endurance in a high-temperature and high-humidity environment and the degree of toner aggregation after endurance of 20,000 K. The smaller the cohesion degree, the better the fluidity of the toner, and the smaller the cohesion degree change before and after the endurance, the more the deterioration is suppressed.

  In this way, when the degree of aggregation increases due to the deterioration of the toner, coarse particles or the like are generated, and are supplied to the developing unit by the toner conveying member by the circulation of the toner. Thereafter, the toner is taken into the developing sleeve while circulating in the developing portion and is clogged with the elastic blade member that regulates the layer thickness of the toner. As a result, uniform coating of the toner on the developing sleeve is hindered, and toner coating unevenness occurs. As a result of development on the image carrier as it is, vertical stripes appear on the halftone image.

  According to experiments and observations by the inventors, the following three methods were considered as effective methods for removing these deposits.

  (1) The external additive strength of the toner external additive is changed to make it difficult to release the external additive.

  (2) The rubber shape of the elastic blade member that regulates the toner layer thickness is changed to make it difficult to collect aggregates such as coarse particles between the developing sleeve and the elastic blade member.

  (3) The toner conveying member is improved to relieve the pressure applied to the toner between the inner wall near the opening and the elastic sheet member, and convey the toner in soft contact.

  However, the above methods (1) and (2) have a large adverse effect on other images (image density unevenness, density thinness, charge application followability, etc.), and toner deteriorates and aggregates coarse particles. The phenomenon in which things are easily generated has not changed.

  On the other hand, since the method (3) reduces the stress applied to the toner, it is considered possible to suppress products generated by the deterioration of the toner.

  In view of this, the inventor paid attention to the pressure applied to the inner wall in the toner storage portion 104 when the toner conveying member 7 as shown in FIG.

{Relationship between inner wall of toner storage portion and elastic sheet member}
Here, the relationship between the inner wall near the opening of the developing device and the bending of the elastic sheet member 7a in the present embodiment will be described with reference to FIG.

  In the inner wall near the opening, the distance from the tip of the backup portion 7c to the inner wall is the shortest, and the amount of bending of the elastic sheet member 7a is the largest. At this time, the elastic sheet member 7 a bends most severely and applies a large pressure to the toner present in the toner storage unit 104. Therefore, it is considered that the toner is easily rubbed and deteriorated here, and aggregates such as coarse particles due to deterioration are also generated here.

  Therefore, the toner conveying member 7 of the present embodiment uses an elastic sheet member (PPS: polyferylene sulfide) 7 having a thickness of about 50 μm, and is integrated with a backup portion 7c made of a resin material as the stirring support member 7b. What was comprised from the shaft rod which was made was used. Then, the durability test was performed by changing the pressure applied to the inner wall of the toner storage unit 104. FIG. 19 (a) is a table showing the experimental results.

  Note that FIG. 19 shows the result of evaluating density unevenness on the image due to vertical stripes, fading, density followability in continuous high printing, etc. of the halftone image of the developing device using the toner conveying member 7 in this embodiment. FIG. In the figure, ◎, ，, and x are ranked in stages with respect to the occurrence level and occurrence frequency of vertical stripes and fading, and ◎ indicates that no occurrence has occurred. A circle indicates a level at which occurrence of a minor object was confirmed only rarely, but no problem was observed in actual use. A circle indicates that the above-mentioned image defect was confirmed.

  From this experimental result, when rubbing the bottom shape of the toner storage portion 104 at one point in the longitudinal direction on the elastic sheet member 7a, the pressure at one point in the longitudinal direction is about 5 mN (about 0.5 gf) or more. The range in which the pressure corresponding to the maximum amount of change in the toner storage portion was about 130 mN (about 13.0 gf) or less was a good result for “vertical stripes” and “fading”. Further, in this experiment, PPS of about 50 μm was used as the elastic sheet member 7a. However, as a result of investigation by the inventors, even if the thickness of the elastic sheet member 7a is changed, if it is within the above set condition range, “ Good results were obtained for “longitudinal stripes” and “fading”.

  Next, the pressure P received from the elastic sheet member of the toner conveying member 7 was examined. As described above, the toner conveying member 7 includes the stirring support member 7b in which the elastic sheet member 7a and the backup unit 7c are integrated. In view of the configuration, it is considered that the elastic sheet member 7a should have a certain amount of deflection. When there is almost no amount of deflection, the toner conveyance force is too great, and the density of the toner (packing) is increased in the developing unit 108. On the other hand, if the amount of bending is too large, the conveyance force is insufficient and toner supply is poor. Both cause “fading”.

  Therefore, the pressure P when the elastic sheet member 7a was penetrated 1.5 mm vertically downward with respect to a certain point in the longitudinal direction was measured as follows.

  After fixing the toner conveying member on a flat surface, attach the force gauge (FGC-0.2 SHIMPO) to the height gauge (Model: 192-601 Mitutoyo) and touch the tip of the force gauge to the elastic sheet member 7a. As a reference, measure the pressure when 1.5 mm is penetrated vertically downward with a height gauge. The range in which the measurement is performed is a range where the inner wall of the toner storage unit 104 is actually contacted and rubbed, and is a range from 1.5 mm to 5.5 mm in the short direction from the tip of the elastic sheet member 7a. The backup amount was changed within the range, and 10 points were measured in the longitudinal direction. FIG. 20 shows a schematic diagram of the apparatus used in this experiment. Therefore, the results of the investigation performed on the measured pressure P are as shown in the table of FIG. 19 (b).

  Therefore, from these result experiments, a good result was obtained when the pressure P was in the range of about 5 mN (about 0.5 gf) ≦ P ≦ about 55 mN (about 5.5 gf). The best result for all conditions is that the pressure P is in the range of about 10 mN (about 1.0 gf) ≦ P ≦ about 50 mN (about 5.0 gf), and this range is more preferable.

  Note that, as described above, the configuration in which the toner is more efficiently conveyed to the developing unit 108 while suppressing the pressure applied to the inner wall of the toner storage unit 104 from the toner conveyance member 7 is the same as the configuration described in the first embodiment. It is the same.

  That is, as shown in FIG. 5, B <A <C, and the axial center O of the toner conveying member 7 is vertically below a straight line connecting the end portions α and β. Yes.

  And also in this embodiment, it is comprised by the dimension similarly to 1st Embodiment. The distance A is 18 mm, the distance B is 16.5 mm, and the toner conveying member length C is 20 mm. Further, the axis O of the toner conveying member is configured to be arranged vertically below the straight line connecting the opening end portions α and β, that is, the plane including the opening, and the toner conveying member rubs the bottom shape of the toner accommodating portion. The toner is pumped up and supplied to the developing unit through the opening.

  Accordingly, the toner is supplied from the toner storage unit 104 to the developing unit 108 by the mechanism described with reference to FIGS. 6 to 8 in the first embodiment while obtaining the same effects as the first embodiment.

[Sixth Embodiment]
Next, a developing device according to a sixth embodiment will be described. In this embodiment, the basic configuration of the developing device and the basic configuration of the image forming apparatus in which the developing device is used are the same as those in the first embodiment. Therefore, the members having the same functions as those in the first embodiment are the same here. The description will be omitted with reference numerals, and only the parts different from the first embodiment will be described.

  FIG. 21 is an explanatory vertical sectional view of a developing device according to the sixth embodiment. This embodiment has the same configuration as that of the fifth embodiment described above, but differs from the fifth embodiment in that the opening 200 is arranged perpendicular to the horizontal plane.

  The axial center of the toner conveying member 7 in the fifth embodiment described above is arranged so that the rotation radius of the toner conveying member 7 follows the bottom shape of the toner accommodating portion 104, and the toner is pumped up from the toner accommodating portion 104. Supplying to the development section. However, in this embodiment, as in the case of the second embodiment, the axial center of the toner conveying member 7 that sends out the toner in the toner storage portion 104 is arranged slightly above the opening 200, and the toner conveying member Reference numeral 7 denotes a configuration that affects the inner wall of the opening to the ceiling.

  Even in this case, the relationship between the pressure applied to the elastic sheet member 7a of the toner conveying member 7 and the inner wall of the toner accommodating portion 104 satisfies the same relationship as that of the developing device of the fifth embodiment, or similar toner conveying member 7 By using the toner, it is possible to make it difficult for the toner to deteriorate due to aggregation of the toner or liberation / embedding of the external additive. Further, the toner conveyance performance and the circulation state can be maintained until the end, and the toner stirring effect by the toner conveyance member is considered to be more advantageous than the conventional configuration.

[Seventh Embodiment]
Next, a developing device according to a seventh embodiment will be described. In this embodiment, the basic configuration of the developing device and the basic configuration of the image forming apparatus in which the developing device is used are the same as those in the first embodiment. Therefore, the members having the same functions as those in the first embodiment are the same here. The description will be omitted with reference numerals, and only the parts different from the first embodiment will be described.

  A feature of this embodiment is that the developing device 8 described in each of the above-described embodiments is provided in an integrated cartridge container together with a photosensitive drum, a cleaning device, and a charging roller (charging device) to constitute a process cartridge 6. This process cartridge can be detachably attached to the apparatus main body.

  FIG. 22 is a longitudinal cross-sectional explanatory view showing an example of a process cartridge, and FIG. 23 is a vertical cross-sectional explanatory view showing a state in which the process cartridge is mounted on the apparatus main body 101 of the image forming apparatus.

  In the present embodiment, the developing device 8 having the configuration of the above-described embodiment, the photosensitive drum 111, the cleaning device 112, and the charging roller (charging device) 103 are integrated by an integrated cartridge container 6 to be a process cartridge 6. Is configured. On the apparatus main body 101 side, a mounting means for mounting the process cartridge 6 is provided, so that an image can be formed by mounting the process cartridge 6.

  When the developing device 8 uses up the toner 109, the other photosensitive drum 111, the charging roller 103, and the cleaning device 112 are designed to reach the end of their lives almost simultaneously. Therefore, the user can always obtain a stable image while the toner in the process cartridge 6 is present, and has an advantage that it can be easily replaced because it is an integral type.

  In addition, in addition to the advantages inherent in the process cartridge, the developing device 8 in the process cartridge 6 is appropriately configured with the opening 200 existing between the developing unit 108 and the toner storage unit 104 described in the above-described embodiment. Thus, the advantage of easily preventing packing and initial density reduction can be added.

  Further, the process cartridge according to the present embodiment prevents toner leakage during transportation by sealing the opening 200 with a seal member at the time of shipment. Therefore, in a cross section perpendicular to the axis of the developing sleeve 105, a straight line connecting the point A and the point B is substantially parallel to a seal member mounting surface that seals the opening 200 in the frame of the toner storage unit 104. With this configuration, the sealing performance is improved and toner leakage is reliably prevented.

  In the present embodiment, an example in which not only the photosensitive drum 111 and the developing device 8 are integrated as a process cartridge but also a charging device and a cleaning device is shown. However, as a form of the process cartridge, the photosensitive drum 111 acts on the photosensitive drum 111. If at least the developing device 8 is provided as the process means, it is possible to prevent packing or the like by the process cartridge.

1 is an overall schematic explanatory diagram of an image forming apparatus. FIG. 2 is a longitudinal cross-sectional explanatory view of the developing device according to the first embodiment. FIG. 4 is an explanatory diagram of a drive transmission and spacing holding configuration of a photosensitive drum and a developing sleeve. FIG. 6 is an explanatory diagram of a toner conveying member disposed in a toner storage unit. FIG. 3 is an explanatory diagram illustrating configurations of an opening and a toner conveying member according to the first embodiment. FIG. 6 is an explanatory diagram of a toner feeding state by rotation of a toner conveying member. FIG. 6 is an explanatory diagram of a toner feeding state by rotation of a toner conveying member. FIG. 5 is an explanatory diagram illustrating toner circulation in a developing unit according to the first embodiment. It is a longitudinal cross-sectional explanatory drawing of the developing device which concerns on 2nd Embodiment. FIG. 10 is an explanatory cross-sectional view illustrating positions of an opening and a toner transport member of a developing device according to a third embodiment. FIG. 10 is an explanatory cross-sectional view illustrating positions of an opening and a toner transport member of a developing device according to a third embodiment. FIG. 10 is an explanatory cross-sectional view illustrating positions of an opening and a toner transport member of a developing device according to a third embodiment. It is a table | surface figure which shows the experimental result by the developing device which concerns on 3rd Embodiment. It is a graph which shows the state of generation | occurrence | production of fading by experiment using the developing device which concerns on 3rd Embodiment. It is explanatory drawing of the toner conveyance state by the developing device which concerns on 3rd Embodiment. It is a graph which shows the state of generation | occurrence | production of fading by experiment using the developing device which concerns on 4th Embodiment. It is explanatory drawing of the toner conveyance state by the developing device which concerns on 4th Embodiment. It is explanatory drawing which shows the bending of the inner wall near the opening of the developing device in 5th Embodiment, and an elastic sheet member. It is a table | surface figure which shows the experimental result by the developing device which concerns on 5th Embodiment. It is explanatory drawing of the pressure measuring device used in performing the experiment by the developing device which concerns on 5th Embodiment. It is a longitudinal cross-sectional explanatory drawing of the developing device which concerns on 6th Embodiment. It is a longitudinal cross-sectional explanatory drawing which shows an example of a process cartridge. FIG. 3 is a longitudinal cross-sectional explanatory view showing a state where a process cartridge is mounted on the apparatus main body of the image forming apparatus. It is explanatory drawing of the image forming apparatus which concerns on a prior art. It is explanatory drawing of the developing device which concerns on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 7 ... Toner conveyance member 7a ... Elastic sheet member 7b ... Agitation support member 7c ... Backup part 8 ... Developing device
101 ... Main unit
102 ... Exposure apparatus
103… Charging roller
104 ... Toner storage
105… Development sleeve
106… Magnet
107a ... elastic blade
107b ... support sheet metal
108… Developer
108a ... opening
109 ... Toner
110… Transfer roller
111… Photosensitive drum
112… Cleaning device
113… Cleaning blade
114… Transfer material
115. Fixing device
116… feed roller
117… Feed cassette
200 ... opening
209… Kolo
211… Photoreceptor drum gear
212… Development sleeve gear α… Open upstream end β… Open downstream end

Claims (12)

A developing unit having a magnetic field generating means that carries a developer and is fixed inside, a developer unit including a rotatable developer carrier, a developer storage unit that stores the developer, and a developer storage unit In a developing device including a rotatable developer conveying member using an elastic sheet member that conveys the developer to the developing unit, and having an opening connecting the developing unit and the developer accommodating unit.
A distance between the opening upstream end of the opening in the developer conveying direction and the rotation axis center of the developer conveying member is A,
The distance between the downstream end of the opening in the developer conveying direction at the opening and the rotation axis center of the developer conveying member is B,
The length from the rotation axis center of the developer conveying member to the rotation tip of the developer conveying member is taken as C,
B <A <C
Furthermore, the rotation axis center of the developer conveying member is vertically below a straight line connecting the upstream end portion of the opening and the downstream end portion of the opening. A developing unit having a magnetic field generating means that carries a developer and is fixed inside, a developer unit including a rotatable developer carrier, a developer storage unit that stores the developer, and a developer storage unit In a developing device including a rotatable developer conveying member using an elastic sheet member that conveys the developer to the developing unit, and having an opening connecting the developing unit and the developer accommodating unit.
The developer conveying member is composed of a stirring support member having a rotating shaft directed in the longitudinal direction, and an elastic sheet member formed in a plate shape and having a base end fixed to the stirring support member,
Gravity direction is negative,
The amount of displacement from the center of the rotation axis of the developer conveying member to the plane including the elastic sheet when the rotation front end of the elastic sheet member in the developer conveying member faces the opening side is represented by X,
When the amount of displacement from the center of the rotation axis of the developer conveying member to the horizontal plane including the upstream end of the opening in the developer conveying direction in the opening is Y,
Y <X
A developing device having the following relationship: A distance between the opening upstream end of the opening in the developer conveying direction and the rotation axis center of the developer conveying member is A,
The distance between the downstream end of the opening in the developer conveying direction at the opening and the rotation axis center of the developer conveying member is B,
The length from the rotation axis center of the developer conveying member to the rotation tip of the developer conveying member is taken as C,
B <A <C
The developing device according to claim 2, wherein the rotation axis center of the developer conveying member is vertically below a straight line connecting the upstream end of the opening and the downstream end of the opening. When the distance between the horizontal plane including the opening upstream end and the horizontal plane including the opening downstream end is Z,
Y <X <Y + Z
The developing device according to claim 3, wherein: A developing unit having a magnetic field generating means that carries a developer and is fixed inside, a developer unit including a rotatable developer carrier, a developer storage unit that stores the developer, and a developer storage unit In a developing device including a rotatable developer conveying member using an elastic sheet member that conveys the developer to the developing unit, and having an opening connecting the developing unit and the developer accommodating unit.
When the developer conveying member rubs the bottom shape of the developer accommodating portion, the pressure at a certain point in the longitudinal direction is 5 mN or more, and the amount of change corresponding to the maximum pressure in the developer accommodating portion is met. A developing device having a pressure of 130 mN or less. The developer conveying member is composed of a stirring support member having a rotating shaft directed in the longitudinal direction, and an elastic sheet member formed in a plate shape and having a base end fixed to the stirring support member,
In the range of 1.5 mm to 5.5 mm in the short direction from the rotation tip of the elastic sheet member, when the pressure when 1.5 mm is inserted in the short direction with respect to one point in the long direction is P,
5mN ≦ P ≦ 130mN
The developing device according to claim 5, wherein: The developer conveying member is composed of a stirring support member having a rotating shaft directed in the longitudinal direction, and an elastic sheet member formed in a plate shape and having a base end fixed to the stirring support member,
In the range of 1.5 mm to 5.5 mm in the short direction from the rotation tip of the elastic sheet member, when the pressure when 1.5 mm is inserted in the short direction with respect to one point in the long direction is P,
10mN ≦ P ≦ 50mN
The developing device according to claim 5, wherein: A distance between the opening upstream end of the opening in the developer conveying direction and the rotation axis center of the developer conveying member is A,
The distance between the downstream end of the opening in the developer conveying direction at the opening and the rotation axis center of the developer conveying member is B,
The length from the rotation axis center of the developer conveying member to the rotation tip of the developer conveying member is taken as C,
B <A <C
6. The developing device according to claim 5, wherein the rotation axis center of the developer conveying member is vertically below a line segment connecting the upstream end portion of the opening and the downstream end portion of the opening. The developer is externally added with a charge control agent as an external additive. As the charge control agent, a hydrophobic silica fine powder is used, and 0.5 to 2.0 parts by weight with respect to 100 parts by weight of the binder resin. The developing device according to claim 1, wherein the developing device is externally added within a range. In a process cartridge that is detachable from the image forming apparatus main body,
An electrophotographic photoreceptor;
The developing device according to any one of claims 1 to 9, as process means acting on the electrophotographic photosensitive member,
A process cartridge comprising: In an image forming apparatus including a developing device that develops an electrostatic latent image formed on an electrophotographic photosensitive member with a developer,
11. An image forming apparatus having mounting means for mounting a process cartridge according to claim 10, comprising the electrophotographic photosensitive member and a developing device. In an image forming apparatus including a developing device that develops an electrostatic latent image formed on an electrophotographic photosensitive member with a developer,
An image forming apparatus, wherein the developing device is the developing device according to claim 1.

Images