JP6758887B2 - Develop equipment, process cartridges and image forming equipment - Google Patents

Description

The present invention relates to a developing apparatus, a process cartridge, and an image forming apparatus used in, for example, an electrophotographic system or an electrostatic recording type image forming apparatus. For example, it is suitable for an electrophotographic copier, an electrophotographic printer (laser beam printer, LED printer, etc.), a facsimile machine, a word processor, and the like.

In an image forming apparatus such as a laser printer using an electrophotographic process, a contact developing method using a developing roller having an elastic layer has been proposed as a conventional developing method using a one-component toner. The layer regulation of the developer adhering to the developing roller and the charge addition by triboelectric charging are performed by bringing the toner regulating member into contact with the developing roller.

As the toner regulating member, it has been proposed to use a blade-shaped member in which a thin metal plate is cantilevered and the abdominal surface of the opposite portion abuts on a developing roller (Patent Document 1). Then, the developer coated on the developing roller by the developing blade develops the electrostatic latent image formed on the photosensitive drum by the potential of the bias applied on the developing roller.

Further, in order to stabilize the toner coat layer, only the edge portion (edge edge portion) of the tip of the regulating member made of a flat plate elastic body or the surface including the edge portion (downstream side in the moving direction of the developer carrier when viewed from the edge portion). Surface) is brought into contact with the developer carrier (Patent Document 2).

Japanese Unexamined Patent Publication No. 62-118372 Japanese Unexamined Patent Publication No. 64-57278

By the way, it is known that the charge imparting property of toner is lowered in a high humidity environment. In particular, in the one-component contact developing method in which the toner is charged by triboelectric charging with the toner regulating member, the chance of the toner obtaining an electric charge is very small, so that the effect of the decrease in the charge imparting property of the toner is large. As a result, a problem caused by a decrease in the charge imparting property to the toner, for example, an increase in the amount of fog occurs. Fog is an image defect in which the toner is slightly developed in a white part (non-printing part) that is not originally printed and appears like a background stain, and is a problem caused by a decrease in the charge imparting property to the toner.

Further, in the region where the photoconductor and the developing roller come into contact with each other via the toner, a voltage is applied to the charged toner in the non-printing portion by applying a force acting toward the developing roller from the photosensitive drum. In Patent Document 1, in the voltage application region where the photoconductor and the developing roller come into contact, the toner charge escapes to the developing roller side due to the applied voltage as described above, and the amount of fog due to the attenuation of the toner charge increases. I'm considering it. As a method for suppressing this, it has been proposed to increase the volume resistance of the developing roller. However, simply increasing the volume resistance causes deterioration of developability such as thin density.

In addition, when the developing device is used for a long period of time, the characteristics of the toner may change as the regulating member wears. Therefore, in order to stably regulate the layer thickness of the toner, pressure welding of the regulating member to the developer carrier is performed. The force needs to be high enough. However, in the configuration as in Patent Document 2, the contact area between the regulating member and the developing agent carrier expands as the pressure contact force of the regulating member with respect to the developing agent carrier is increased in order to regulate the layer thickness of the toner. The direction of the pressure contact force is such that it becomes easier. Therefore, when the developing apparatus is used for a long period of time, it may be difficult to stably regulate the layer thickness of the toner.

An object of the present invention is to provide a developing apparatus, a process cartridge, and an image forming apparatus capable of stably obtaining a good image over time even in a high humidity environment while maintaining developability.

In order to achieve the above object, the developing apparatus according to the present invention is applied to a developing agent carrier supporting a developer and the developer supporting body in order to develop an electrostatic latent image formed on the image carrier. The development is provided by providing an elastic member supported by a support member so as to be in contact with the developer, and bringing the tip of the elastic member into contact with the developer carrier so as to face upstream in the rotation direction of the developer carrier. In a developing apparatus having a developer regulating member that regulates the amount of the developer supported on the agent carrier and an urging means for pressing the developer regulating member against the developer carrier, the developer. The carrier has an elastic layer and a surface layer formed around the elastic layer, containing alumina and an organic component, and having a volume resistance higher than that of the elastic layer, and is viewed from the axial direction of the developer carrier. From the other end side of the elastic member supported by the support member with respect to the direction connecting the contact position between the developer carrier and the elastic member and the rotation center of the developer carrier, the developer carrier When the angle formed by the direction extending toward one end is α,
45 ° ≤ α ≤ 80 °
It is characterized by satisfying the following conditions.

Further, another developing apparatus according to the present invention is such that the developer supporting body carrying the developer and the developer supporting body are brought into contact with each other in order to develop the electrostatic latent image formed on the image carrier. An elastic member supported by the support member is provided, and the developer carrier and the elastic member are brought into contact with the developer carrier so as to face upstream in the rotation direction of the developer carrier. Development having a developer regulating member that regulates the amount of the developer supported on the developer carrier at the contact position, and an urging means that presses the developer regulating member against the developer carrier. In the apparatus, the developer carrier has an elastic layer and a surface layer formed around the elastic layer, containing alumina and an organic component, and having a volume resistance higher than that of the elastic layer. when viewed from the axial direction, the a tip end surface that extends an end surface of the elastic member, and the surface obtained by extending the surface facing the developer carrying member leading to the surface, and point P intersects the The straight line PQ connecting the rotation center Q of the developer carrier is set to be the shortest, and the straight line PQ and the developer carrier are supported from the other end side of the elastic member supported by the support member. When the angle formed by the direction extending toward one end in contact is α,
It is characterized in that it satisfies the condition of 45 ° ≤ α ≤ 80 °.

Further, the process cartridge according to the present invention is characterized by having the above-mentioned developing apparatus.

Further, the image forming apparatus according to the present invention is characterized by having the above-mentioned developing apparatus.

In addition, another image forming apparatus according to the present invention carries an image carrier carrying an electrostatic latent image and a developer, contacts the image carrier, and develops the electrostatic latent image with the developer. In an image forming apparatus having a developer carrier and a developer regulating member for regulating the amount of the developer supported on the developer carrier, the developer carrier is an elastic layer and said. The developer-regulating member has a surface layer formed around the elastic layer, containing alumina and an organic component, and having a higher volume resistance than the elastic layer, and at least one end of the developer-regulating member is in contact with the developer-supported body. It has an elastic member in contact and a support member that cantileverally supports the elastic member at the other end opposite to the abutting portion in contact with the developer carrier, and the elastic member is the surface of the developer carrier. The counter contact with respect to the moving direction of the developer, and the contact position between the developer carrier and the elastic member when viewed from the axial direction of the developer carrier and the direction connecting the rotation center of the developer carrier. It is characterized in that the angle formed by the direction extending from the other end side of the elastic member supported by the support member to the one end side in contact with the developer carrier is 45 to 80 degrees.

In addition, another image forming apparatus according to the present invention carries an image carrier carrying an electrostatic latent image and a developer, contacts the image carrier, and develops the electrostatic latent image with the developer. In an image forming apparatus having a developer carrier and a developer regulating member for regulating the amount of the developer supported on the developer carrier, the developer carrier is an elastic layer and said. The developer-regulating member has a surface layer formed around the elastic layer, containing alumina and an organic component, and having a higher volume resistance than the elastic layer, and at least one end of the developer-regulating member is in contact with the developer-supported body. It has an elastic member in contact and a support member that cantileverally supports the elastic member at the other end opposite to the abutting portion in contact with the developer carrier, and the elastic member is the surface of the developer carrier. When viewed from the axial direction of the developer carrier, the surface on which the end surface on the tip end side of the elastic member is extended and the surface facing the developer carrier connected to this surface are opposed to each other. a surface which is extended, the point P of intersection, the rotation center Q of the developer carrier sets a straight line PQ such that the shortest connecting, and the straight line PQ, the support member of the elastic member It is characterized in that the angle formed by the direction extending from the other end side supported by the above to the one end side in contact with the developer carrier is 45 to 80 degrees.

According to the present invention, it is possible to obtain a good image stably over time even in a high humidity environment while maintaining the developability.

Schematic cross-sectional view of an image forming apparatus equipped with a developing apparatus according to an embodiment of the present invention. Schematic cross-sectional view of a process cartridge equipped with the developing apparatus according to the embodiment of the present invention. Schematic cross-sectional view of a modified example of a process cartridge Schematic diagram illustrating the regulation blades of Examples 1 and 2. Schematic diagram illustrating a swing type regulation blade Schematic diagram illustrating the regulation blade of the third embodiment Schematic diagram illustrating the regulation blade of Example 4. Schematic of a developing roller according to an embodiment of the present invention Schematic diagram illustrating the measurement of the volume average resistance of the developing roller Schematic diagram illustrating impedance measurement of a developing roller Schematic diagram illustrating changes in toner charge before and after passing through the developing nip Schematic diagram for explaining the regulation blade and toner flow during durability in Comparative Example 1. Schematic diagram for explaining the regulation blade and toner flow during durability in Comparative Example 3 Schematic diagram for explaining the regulation blade of Comparative Example 1. Schematic diagram explaining the current flowing during development Schematic diagram illustrating a modified example of the regulation blade

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<< First Embodiment >>
(Image forming device and process cartridge)
FIG. 1 is a schematic configuration diagram of an image forming apparatus 100 equipped with a developing apparatus according to the present embodiment, and the image forming apparatus 100 shows a full-color laser printer using an electrophotographic process. Further, FIG. 2 is a schematic cross-sectional view of a process cartridge 11 (hereinafter referred to as a cartridge) equipped with the developing apparatus according to the embodiment of the present invention. The cartridge 11 integrally includes a photoconductor unit 18 including a photosensitive drum (photoreceptor) 1 and a developing device 4 as a developing unit.

a) Image forming apparatus 100
The overall schematic configuration of the image forming apparatus 100 will be described below. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments described below are intended to limit the scope of the present invention to those. It's not a thing.

In FIG. 2, the photosensitive drum (photoreceptor) 1 which is an image carrier is rotated in the direction of arrow r and is charged to a uniform potential Vd by a charging roller 2 which is a charging device. Next, it is exposed by a laser beam from a laser optical device 3 (FIG. 1) which is an exposure device, and an electrostatic latent image is formed on the surface thereof. This electrostatic latent image is developed by the developing device 4 and visualized as a toner (developer) image. The visualized toner image on the photoconductor 1 is transferred to the intermediate transfer body 6 (FIG. 1) by the primary transfer device 5 (FIG. 1), and then transferred to the recording medium (transfer to be transferred) by the secondary transfer device 7 (FIG. 1). It is transferred to paper 8 (FIG. 1) which is a material).

The transfer residual toner (transfer residual developer) remaining on the photoconductor 1 without being transferred is scraped off by a cleaning blade 9 (FIG. 2) which is a cleaning device. Then, the cleaned photoconductor 1 repeats the above-mentioned actions to form an image. On the other hand, the paper 8 to which the toner image is transferred is fixed by the fixing device 10 (FIG. 1) and then discharged to the outside of the machine.

b) Photoreceptor unit 18 in cartridge 11
In FIG. 2, the photoconductor 1, the charging roller 2, the developing device 4, and the cleaning blade 9 are integrally configured as the photoconductor unit 18, and are integrated together with the developing device 4 described later, and the image forming apparatus main body ( It is configured as a cartridge 11 that can be attached to and detached from the main body). As shown in FIG. 1, the main body is provided with four mounting portions for the cartridge 11. Then, a cartridge 11 filled with yellow, magenta, cyan, and black toners is mounted from the upstream side in the moving direction of the intermediate transfer body 6, and a color image is formed by sequentially transferring to the intermediate transfer body 6. be able to.

The photoconductor 1 is formed by laminating an organic photoconductor coated on an Al (aluminum) cylinder, which is a conductive substrate, in the order of a positive charge injection prevention layer, a charge generation layer, and a charge transport layer. .. Further, allylate was used as the charge transport layer of the photoconductor 1, and the film thickness of the charge transport layer was adjusted to 23 μm.

This charge transport layer is formed by dissolving a charge transport material in a solvent together with a binder. Examples of the organic charge transport material include acrylic resin, styrene resin, polyester, polycarbonate resin, polyarylate, polysulfone, polyphenylene oxide, epoxy resin, polyurethane resin, alkyd resin, unsaturated resin and the like. These charge transporting materials can be used alone or in combination of two or more.

The charging roller 2 is provided with a semi-conductive rubber layer on a core metal which is a conductive support, and the resistance of the charging roller 2 is about 10 when a voltage of 200 V is applied to the conductive drum. ^It shows a resistance of ⁵ Ω.

c) Developing apparatus 4 as a developing unit in the cartridge 11.
The developing apparatus 4 includes a toner 12, a developing container 13 which is a developing agent accommodating portion, a developing roller 14 which is a developing agent carrier, a supply roller 15 which supplies toner 12 to the developing roller 14, and a developing roller 14. A regulating blade 16 which is a developer regulating member that regulates toner is provided. The developing roller 14 includes a core metal electrode 14a and a rubber layer 14b as a conductive elastic layer, and the regulation blade 16 includes a thin plate elastic member (elastic member) 16a, a support member 16b, a swing fulcrum shaft 16c, and the addition. It includes a compression spring 16d, which will be described in detail later.

The developing roller 14 is an elastic roller, which carries a non-magnetic developer and develops by contacting the surface of the photoconductor 1. Toner is supplied to the developing roller 14 by the supply roller 15 in contact with the developing roller 14. The supply roller 15 conveys toner from the inside of the developing container 13 and attaches it to the developing roller 14, and also has a function of temporarily removing the toner remaining on the developing roller 14. Then, the layer regulation of the toner adhering on the developing roller 14 and the charge addition by triboelectric charging are performed by bringing the regulating blade 16 into contact with the developing roller 14.

The supply roller 15 comes into contact with the developing roller 14 (rotation direction 14r) and rotates in the direction of the arrow in FIG. 1, and one end of the regulation blade 16 is in contact with the developing roller 14.

In FIG. 2, the supply roller 15 is provided with a urethane foam layer 15b around a core metal electrode 15a having an outer diameter of φ5.5 (mm), which is a conductive support. The outer diameter of the entire supply roller 15 including the urethane foam layer 15b is φ13 (mm). The penetration amount of the supply roller 15 and the developing roller 14 is 1.2 mm. At the contact portion with the developing roller 14, the supply roller 15 rotates in a direction in which the speeds are opposite to each other. The powder pressure of the toner 12 existing around the urethane foam layer 15b acts on the urethane foam layer 15b, and the supply roller 15 further rotates to take the toner 12 into the urethane foam layer 15b.

The supply roller 15 containing the toner 12 supplies the toner 12 to the developing roller 14 at the contact portion with the developing roller 14, and further rubs the toner 12 to give the toner 12 a preliminary triboelectric charge. On the other hand, the supply roller that supplies toner to the developing roller 14 also has a role of peeling off the toner remaining on the developing roller 14 without being developed by the developing unit.

The toner 12 supplied from the supply roller 15 to the developing roller 14 reaches the regulation blade 16 and is adjusted to a desired charge amount and toner layer thickness. The regulation blade 16 is a SUS blade having a thickness of 80 μm, and is arranged so as to oppose the rotation of the developing roller 14. The toner 12 on the developing roller 14 is regulated by the regulating blade 16 to obtain a uniform toner layer thickness, and a desired amount of charge is obtained by triboelectric charging by rubbing. Further, a voltage was applied to the regulation blade 16 with a potential difference of −200 V with respect to the developing roller 14. This potential difference is for stabilizing the toner coat layer.

The toner layer formed on the developing roller 14 by the regulating blade 16 is conveyed to a developing section that comes into contact with the photoconductor 1, and reverse development is performed in the developing section. At the contact position A shown in FIG. 2, the amount of penetration of the developing roller 14 into the photoconductor 1 is set to 40 μm by a roller (not shown) at the end of the developing roller 14. The surface of the developing roller 14 is deformed by being pressed against the photoconductor 1, so that a developing nip is formed and development can be performed in a stable contact state.

The developing roller 14 rotates in the same direction with the photoconductor 1 and its developing nip with a peripheral speed ratio of 117% with respect to the photoconductor 1. Such a peripheral speed difference has a role of stabilizing the amount of toner to be developed.

d) Voltage application Next, a specific voltage in this embodiment will be described. By applying −1050V to the charging roller 2, the surface of the photoconductor 1 is uniformly charged to −500V to form a dark potential (Vd), and the printing unit is a laser optical device 3 which is an exposure means. It was adjusted to -100V (bright potential Vl) by the laser from. At this time, by applying a voltage (Vdc) of −300 V to the developing roller 14, the negative polarity toner shifts to a bright potential and reverse development is performed. Further, | Vd-Vdc | was called Vback, and Vback was set to 200V.

e) Toner 12
As the one-component non-magnetic toner which is a developing agent, the toner 12 was adjusted to contain a binder resin and a charge control agent, and was produced so as to have a negative polarity by adding a fluidizing agent or the like as an external additive. The toner 12 was produced by a polymerization method, and the average particle size was adjusted to about 5 μm. Further, the amount of toner to be filled in the developing apparatus 4 is an amount equivalent to 6000 printable images converted to an image ratio of 5%. As a specific example of a horizontal line having an image ratio of 5%, it means an image in which 19 dot line non-printing is repeated after 1 dot line printing.

f) Process speed In the image forming process, the photoconductor 1 is rotationally driven by the image forming apparatus in the direction of arrow r in FIG. 2 at a process speed of 120 mm / sec. Further, the image forming apparatus 100 has a low-speed mode with a process speed of 60 mm / sec in order to secure the amount of heat for fixing when the thick recording paper (thick paper) is passed. Further, in the present embodiment, the operation is performed only in two types of process modes, but a plurality of process modes may be provided depending on the recording paper, and the control corresponding to each process mode can be executed. You may be.

g) Modification example of the process cartridge FIG. 3 is a schematic configuration diagram showing a modification of the process cartridge. The image recording device equipped with this modification is a laser printer that uses a transfer type electrophotographic process and a toner recycling process (cleanerless system). The same points as those of the image recording device shown in FIG. 1 will not be described again, and different points will be described. The characteristic point in this modified example is that the drum cleaner 9 is abolished and the transfer residual toner is recycled. The transfer residual toner is circulated so as not to affect other processes such as charging, and the toner is collected in the developing device 4. Specifically, the following configuration was changed with respect to the process cartridge shown in FIG.

Regarding charging, the charging roller 2 is the same as that shown in FIG. 2, but in this modified example, the charging roller 2 is provided with a charging roller contact member 20 for the purpose of preventing toner stains on the charging roller. Be prepared. Even if the charging roller 2 is contaminated with toner of the opposite polarity (positive polarity), the toner charge is charged from plus to minus, and the toner is quickly discharged from the charging roller for simultaneous development and cleaning with a developing device. It becomes possible to collect it. The charging roller contact member 20 used a 100 μm polyimide film and contacted the charging roller 2 at a linear pressure of 10 (N / m) or less.

Further, in order to improve the toner recoverability in the developing apparatus 4, the absolute value of the non-exposure potential Vd and the value of Vback are set large. Specifically, by applying a voltage of -1350 V to the charging roller, the surface of the photoconductor 1 was set to a uniform potential Vd = −800 V. Further, by setting the development bias to −300V, Vback = 500V was set.

(Examples and Comparative Examples)
Hereinafter, each embodiment in the present embodiment and each comparative example for comparison with the present embodiment will be described in detail in relation to the surface layers of the regulation blade 16 and the developing roller 14.

1) Example 1
a1) Regulatory blade: BL1 (Fig. 4, α = 75 °)
The regulation blade 16 as a toner regulation member (developer regulation member) in this embodiment will be described in detail. In Figure 2, the regulating blade 16 is disposed so as to contact the developing roller 1 4 downstream from the supply roller 15 with respect to the rotation direction 14r of the developing roller 14. The regulation blade 16 includes a thin plate elastic member (elastic member) 16a and a support sheet metal 16b which is a support member for supporting the plate material which is the elastic member 16a.

The free end of the elastic member 16a, that is, the tip on one end side, is provided so as to face the developing roller 14 from the downstream side to the upstream side in the rotation direction 14r and to make a counter contact with the developing roller 14. Further, a support sheet metal 16b for cantilevering and supporting the elastic member 16a is provided at the other end on the side opposite to the contact portion of the elastic member 16a that comes into contact with the developing roller 14. Here, the elastic member 16a is an elastic member (leaf spring) made of a thin plate-shaped metal. On the other hand, the support sheet metal 16b is a metal plate thicker than the elastic member 21a, is bent in an L shape, and is attached by a swing frame 17 having a swing fulcrum shaft 16c. The support sheet metal 16b is a support member that supports the elastic member 16a.

Swinging frame 17 is a longitudinal frame having a swing fulcrum shaft 16c on both ends in the (axial direction of the developing roller 1 4). The swing fulcrum shaft 16c is a shaft portion that makes the swing frame body 17 and the support member 16b rotatable, and is held by the frame body (development container 13) of the developing device 4.

Next, the pressing force of the regulation blade 16 against the developing roller 14 will be described. A pressurizing spring 16d, which is a pressurizing means for pressing against the support member 16b, is installed in the frame of the developing apparatus 4, and the regulating blade 16 is developed by rotating around the swing fulcrum shaft 16c. Pressurized contact with the roller 14. The pressure spring 16d has a function as an urging means for pressing the elastic member 16a against the developing roller 14 by applying a moment to the elastic member 16a.

In this embodiment, the pressure spring 16d is a compression spring as shown in FIG. 2, but there are no particular restrictions on the method of pressurizing the elastic member 16a, and instead of the compression spring, a tension coil spring, a leaf spring, or the like is used. May be applied as an alternative pressurization method.

The pressure spring 16d is not directly attached to the elastic member 16a, but is attached to the support sheet metal 16b. This is to prevent the elastic member 16a from being deformed when the pressure spring 16d directly urges the elastic member 16a. In particular, in this embodiment, the support sheet metal 16b is a metal thicker than the elastic member 16a, and is further bent in an L shape, so that it has high strength and is deformed even when it receives an urging force from the pressure spring 16d. It's hard to do. As a result, deformation of the support sheet metal 16b can be suppressed. As a result, the force with which the elastic member 16a of the regulation blade 16 presses the developing roller 14 can be kept constant.

Next, the positional relationship between the regulation blade 16 and the developing roller 14 will be described with reference to FIG. When viewed from the axial direction of the developing roller 14, as shown in FIG. 4A, from the direction connecting the position P and the rotation center Q of the developing roller 14 and the other end side supported by the support sheet metal 16b of the elastic member 16a. Let α be the angle formed by the direction extending toward one end in contact with the developing roller 14. In this embodiment, the position P is the contact position between the developing roller 14 and the elastic member 16a.

In addition, the point (ridge line) at which the extending surface extending the end surface on the distal end side of the elastic member 16a and the extending surface extending the facing surface facing the developing roller 14 connected to this end surface intersect is defined as the position P. , The straight line PQ may be set to be the shortest. Then, the angle α formed by the position P, the direction connecting the PQ connecting the rotation center Q of the developing roller 14, and the direction extending from the other end side supported by the support sheet metal 16b of the elastic member 16a to the one end side in contact with the developing roller 14. Is preferably 45 to 80 degrees. That is, it is preferable that the following conditions are satisfied with respect to the angle α for the elastic member 16a to reliably make edge contact with the developing roller 14.

45 ° ≤ α ≤ 80 °
Here, as shown in FIG. 4B, the radius of the developing roller 14 is M, and a surface parallel to the direction extending from the other end side supported by the support sheet metal 16b of the elastic member 16a to the one end side in contact with the developing roller 14. When the interval between and is H, the following equation is satisfied.

sin45 ° ≤ H / M ≤ sin80 °
If the angle α is smaller than 45 °, the tip of the elastic member 16a is likely to be caught by the rotation of the developing roller 14, and it becomes difficult to stably regulate the layer thickness of the toner. Further, especially when a thin metal plate manufactured by punching (pressing) with a metal plate mold is used as the elastic member 16a, burrs on the fracture surface easily affect the regulation of the layer thickness of the toner, and after the regulation. Vertical streaks are likely to occur in the thin layer of the toner.

Further, when the angle α is larger than 80 °, fused substances such as toner agglomerates and agglomerates are generated on the surface of the regulation blade 16 as described in FIG. 12 regarding Comparative Example 1 described later, and the toner coat. Streaks are generated on the layers, and vertical lines are generated in the halftone image.

In view of these, in this embodiment, the angle α is set to 75 °. Further, in order to stabilize the degree of deflection deformation (the magnitude of the deflection angle) of the elastic member 16a with respect to the pressing force generated between the developing roller 14 and the regulation blade 16, the Young's modulus is 68,000 MPa or more. Is desirable. That is, it is desirable that the elastic member 16a is made of metal. Therefore, in this embodiment, stainless steel is used as the elastic member 16a, but other metals such as phosphor bronze and aluminum may be used. The metal referred to here includes an alloy.

Next, the position of the swing fulcrum R in this embodiment of the swing type will be described with reference to FIG. The distance PR between the swing fulcrum R and the intersection P is set to be smaller than the distance QR between the swing fulcrum R and the rotation center Q of the developing roller 14. As a result, even if the outer diameter of the developing roller 14 is shaken or the like, the tip of the regulating blade can be reliably brought into contact with the tip of the regulating blade. That is, the developing roller 14 radial fluctuations and depressions, even if variations in the assembly tolerances of the developing device 4 is caused, the elastic member 16a both by rotating the fulcrum Yurado支point R is securely abuts.

b1) Development roller: Dev1 (Fig. 8)
The developing roller (the surface layer around the elastic layer contains alumina and organic components and has a higher volume resistivity than the elastic layer) shown in FIG. 8 was produced as follows. Here, alumina refers to aluminum oxide such as α-alumina and γ-alumina, aluminum oxide hydrate such as boehmite and pseudo-boehmite, aluminum hydroxide, and an aluminum compound obtained by hydrolyzing and condensing aluminum alkoxide described later. Shown.

In this embodiment, a conductive rubber layer 14b containing a conductive agent is provided around a core metal electrode 14a having an outer diameter of φ6 (mm), which is a conductive support, and the outer diameter of the substrate 14b1 of the developing roller 14 is provided. Was set to φ11.5 (mm). Here, as the material of the rubber layer 14b, general rubber such as silicon rubber, urethane rubber, EPDM (ethylene / propylene copolymer), hydrin rubber, or a rubber in which these are mixed can be used.

In this example, a silicon rubber of 2.5 mm and a urethane layer of 10 um were formed to form a substrate 14b1. Further, as the conductive agent, a desired resistance value can be obtained by dispersing carbon particles, metal particles, ionic conductive particles and the like, and carbon particles were used in this example. Further, with respect to the hardness of the entire developing roller 14, the developing roller 14 having a desired hardness was produced by adjusting the amount of silicon rubber and the amount of silica as a filler.

Next, the coating liquid as the surface layer material will be described. Aluminum oxide as an alumina powder (average particle size 50 nm, average of 10 points by SEM) and urethane acrylate as an organic component (manufactured by Shin-Nakamura Chemical Industry Co., Ltd., UA-1100H) are mixed in a blending ratio of 3/7 to add methyl ethyl ketone. It was adjusted by diluting as appropriate. Further, a photoinitiator (BASF Irgacure 184) was added in an amount of 5% based on the weight of the urethane acrylate. The prepared coating liquid was spray-coated on the above-mentioned developing roller 14 and irradiated with ultraviolet rays (low-pressure mercury) to form 1.2 um as a urethane acrylic resin surface layer containing alumina.

The resin as an organic component used in this example is not particularly limited as long as it cures when irradiated with ionizing radiation such as an electron beam or ultraviolet rays. For example, urethane acrylate resin, polyester acrylate resin, epoxy acrylate resin and the like can be appropriately selected. In addition, when it is cured by ultraviolet irradiation, it is desirable to mix acetophenones, benzophenones and the like as a photopolymerization initiator.

As a specific example of the ultraviolet curable polyfunctional acrylic having two or more (meth) acryloyl groups in the molecule as the above resin, neopentylglycoldi (meth) acrylic, 1,6 hexanedio- Luzi (meta) acrylic can be mentioned. Alternatively, trimethylolpropanetri (meth) acrylate, ditrimethylolpropanetetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol (meth) acrylate may be mentioned. Can be done.

Alternatively, the polio polyacryllate such as dipentaerythritol hexa (meth) acrylate, the diacrylate of bisphenol A diglycidyl ether, and the diacrylate of neopentylglycol diglycidyl ether may be mentioned. Can be done. Alternatively, epoxy (meth) acrylics such as di (meth) acrylics of 1,6 hexanedioldiglycidyl ether can be mentioned. Alternatively, a polyester (meth) acrylicate that can be obtained by esterifying a polyvalent alcohol, a polyvalent carboxylic acid and / or its anhydride and acrylic acid can be mentioned.

Alternatively, a urethane (meth) acrylic obtained by reacting a multivalent alcohol, a polyvalent isocyanate and a hydroxyl group-containing (meth) acrylic, a polysiloxane poly (meth) acrylic, and the like can be mentioned. Can be done.

The above-mentioned polymerizable acrylic may be used alone or in combination of two or more, and may be used alone or in combination of two or more, 2-hydroxy (meth) acrylic, 2-hydroxypropyl (meth) acrylic, and glycidyl (meth). It is also possible to add a monofunctional acylate such as an acylate. In addition, a polymerizable oligomer used for the purpose of adjusting the hardness can be added.

Examples of such oligomers include terminal (meth) acrylicate polymethyl (meth) acrylicate, terminal styrylpoly (meth) acrylicate, and terminal (meth) acylate polystyrene. Alternatively, macromonomers such as terminal (meth) acrylate polyethylene glycol, terminal (meth) acrylonitrile-styrene copolymer, and terminal (meth) acrylicate styrene-methylmethacrylate copolymer can be mentioned. be able to.

The resistance value of the developing roller 14 is preferably 2 × 10 ⁴ Ω to 5 × 10 ⁶ Ω. This is because if it is 2 × 10 ⁴ Ω or less, the current flowing through the elastic layer increases and the required amount of current increases. Further, when it is 5 × 10 ⁶ Ω or more, the current flowing during development is likely to be hindered. In this example, a developing roller 14 having a resistance value of 5 × 10 ⁵ Ω was used.

(Measurement method of resistance of developing roller)
A method of measuring the resistance of the developing roller 14 will be described. FIG. 9 is a diagram illustrating a method for measuring the resistance of the developing roller 14 of this embodiment. The developing roller 14 to be measured has a multi-layer structure composed of a conductive core metal 14a made of stainless steel or the like and an elastic layer 14b formed on the outer periphery thereof. The width of the developing roller 14 in the longitudinal direction (axial direction) is about 230 mm. In this measuring method, a cylindrical member G1 made of stainless steel having a diameter of 30 mm and rotating at a speed of about 48 mm / sec in the direction of the arrow is used. When measuring the resistance, the developing roller 14 is driven to rotate as the cylindrical member G1 rotates.

An end roller is fitted to the end of the developing roller 14 to limit the amount of penetration into the cylindrical member G1 to 40 μm (to make the contact area between the developing roller 14 and the cylindrical member G1 constant). The end roller has a cylindrical shape whose outer diameter is 80 μm smaller than the outer diameter of the developing roller 14. F shown in FIG. 9 indicates a load applied to both ends of the developing roller 14 (both ends of the conductive core metal 14a), and during measurement, a load of 500 g on each side, a total of 1 kg, is applied. The developing roller 14 is pressed toward the cylindrical member G1.

Further, a measurement circuit G2 (FIG. 9) is used for this measurement method. The measurement circuit G2 is composed of a power supply Ein, a resistor Ro, and a voltmeter Eout. In this measurement method, the measurement was performed at Ein: 300 V (DC). Further, as the resistor Ro, a resistor having a resistance value of 100Ω to 10MΩ can be used.

Since the resistor Ro is for measuring a weak current, it is preferable to use a resistance value of × 10-2 to × 10-4 of the resistance of the developing roller 14 to be measured. That is, if the resistance value of the developing roller 14 is about 1 × 10 ⁶ Ω, the resistance value of the resistor Ro may be about 1 kΩ. Using this measuring circuit G2, the resistance value Rb of the developing roller 14 is calculated by the following equation. The value of Eout was measured 10 seconds after the voltage was applied.

Rb = Ro × (Ein / Eout-1) (Ω)
(Measurement of volume resistivity of each layer of developing roller: AC impedance)
Next, the resistivity of each layer of the developing roller 14 will be described. In this embodiment, the volume resistivity of the surface ^{layer, 5 × 10 11 Ω · cm} , the substrate volume resistivity is 10 ⁸ [Omega] cm, the volume resistivity of the surface layer layer is set higher than the volume resistivity of the base body ing. The volume resistivity was measured as follows.

As shown in FIG. 10, three conductive tapes having a width of 5 mm are wound around the roller surface of the developing roller 14 at 1 mm intervals, and direct current is applied between the conductive tape D2 located in the center of the three conductive tapes and the core metal of the developing roller 14. A voltage, which will be described later, in which alternating current is superimposed on the power supply S0 is applied from the power supply S0. The two conductive tapes D1 and D3 other than the central conductive tape D2 described above are grounded to the ground, and the current flowing between the central conductive tape D2 and the core metal is detected by the ammeter S2 in the radial direction of the developing roller 14. Measure the volume resistivity of.

The voltage applied here is changed from a DC voltage of 20 V, an AC voltage of Vpp 1 V, and a frequency of 1 Hz to 1 MeHz, and the volume resistance of each layer is calculated by a Col-Col plot. Further, the cross section of the developing roller 14 was cut out, the film thickness of each layer was measured at 10 points by SEM observation, the average film thickness of each layer was calculated, and the volume resistivity of each layer was derived from the above-mentioned volume resistivity. This impedance measurement was carried out in an environment of 30 ° C. and 80% RH.

As a result of diligent studies, the inventors have recognized that a good image can be obtained by setting the relationship between the volume resistivity of the surface layer of the developing roller 14 and the substrate as described above. First, concentration fluctuations and gradation fluctuations due to the relationship between the volume resistivity of the surface layer and the substrate will be described.

Usually, in order to obtain a stable image, the image density and gradation can be obtained by adjusting the resistance of the substrate and providing an appropriate potential difference between the photoconductor and the developing roller. In this embodiment, since a coating layer (surface layer) having a higher volume resistivity than the substrate is formed, it is considered that changes in image density and gradation can be suppressed.

As shown in FIG. 15A, when the toner on the developing roller 14 having an electric charge is developed from the developing roller 14 onto the photoconductor 1, the amount of electric charge transferred to the developing toner is also applied to the developing roller 14. It flows. When the coating layer (surface layer) having a resistivity lower than the resistivity of the substrate is provided, the current generated at this time easily flows through the surface layer by the path shown in FIG. 15 (c). As a result, a voltage drop occurs from a predetermined value before and after the developing nip where the developing roller 14 and the photoconductor 1 come into contact with each other, the desired electric field strength at the time of development fluctuates, and the image density and gradation property change.

Further, if the thickness of the layer is increased in that state, the current flowing on the surface is further increased, and the electric field strength in the developing nip is further reduced. On the other hand, in this embodiment, since the surface layer having a volume resistivity larger than the volume resistivity of the substrate is provided, the wraparound current can be remarkably suppressed (FIG. 15B), so that the electric field strength in the developing nip is lowered. Can be suppressed. As a result, desired image density and gradation can be obtained.

Therefore, in this embodiment, a good image can be obtained by making the volume resistivity of the surface layer larger than the volume resistivity of the substrate. Further, in order to suppress the current flowing through the surface layer and suppress a significant increase in the overall resistance, the average film thickness of the surface layer is preferably 5.0 um or less. When the average thickness of the surface layer is 5.0 um or more, the wraparound current can be suppressed, but the voltage drop of the surface layer becomes large, and the electric field strength applied to the toner layer in the developing nip decreases, so that development is possible. The amount of toner decreases, causing a decrease in density. The average film thickness of the surface layer in this example was 1.5 um.

The volume resistivity of the surface layer is preferably 10 ¹⁰ to 10 ¹⁴ Ω · cm. When the volume resistivity of the surface layer is 10 ¹⁴ Ω · cm or more, the surface layer thickness varies, and the slight uniformity of the image density decreases. When the volume resistivity of the surface layer is 10 ¹⁰ Ω · cm or less, the surface layer thickness varies locally. Since the toner charge is attenuated, the amount of fog is likely to increase slightly.

In addition, the resin preferably has an alumina and comparable resistivity used in this embodiment, specifically, the volume resistivity of the resin is 10 ⁹ Ω · cm or more 10 ¹⁴ Ω · cm or less Is preferable.

The measurement of the volume resistivity of the resin was calculated by assuming two components of the resin and alumina in the surface layer at the above impedance. The volume resistivity of the resin in this example was 10 ¹¹ Ω · cm. When the volume resistivity of the resin is lower than 10 ⁹ Ω · cm, the attenuation of the toner charge occurs along the resin, if it exceeds 10 ¹⁴ Omega · cm, halftone because charges remain by the print history on the developing roller 14 There is a density difference in the image.

(Measurement of average hardness of developing roller)
The average hardness of the developing roller 14 was measured using an AskerC rubber hardness tester (manufactured by Polymer Meter Co., Ltd.). In this embodiment, a developing roller 14 having an average hardness of 30 degrees to 80 degrees (AskerC) or less, and further 45 degrees to 70 degrees (AskerC) or less is preferably used.

When the average hardness is 80 degrees (AskerC) or more, the toner is melted by rubbing the developing roller 14, causing blade fusion and roller fusion, which is not preferable. Further, the contact state between the developing roller 14 and the photoconductor 1 tends to be unstable. On the other hand, when the average hardness is 30 degrees (AskerC) or less, it becomes difficult to use the developing roller 14 due to deformation due to strong compression strain. In this example, a developing roller 14 having an average hardness of 55 degrees (AskerC) was used.

(Surface hardness of developing roller)
The hardness of the surface layer of the developing roller 14 is preferably 35 ° to 80 ° or less in terms of micro hardness (MD-1 type). Further, it is more preferably 35 ° to 70 °. Further, it is more preferably 40 ° to 70 °. When the surface hardness exceeds 80 °, significant toner deterioration occurs, and the solid black image density and halftone image density decrease due to the deterioration of transferability. Further, when the MD1 hardness is less than 35 °, the wear of the surface layer of the developing roller deteriorates, so that it is not possible to form a stable toner coat layer and an image over time.

2) Comparative Example 1 (conventional technology)
a2) Regulatory blade: BL4 (Fig. 14, α = 82 °)
In the regulation blade 16 shown in FIG. 14 in this comparative example, an elastic member 16a such as a phosphor bronze plate or a stainless steel plate is cantilevered and supported on a support sheet metal fixed to the developing container 13, and the free end side of the facing portion thereof is fixedly supported. It is in contact with the developing roller 14. In this regulated blade configuration, the angle α is 82 °. Further, the support sheet metal uses an iron plate having a thickness of 1.2 mm, and the elastic member 16a is a stainless plate having a thickness of 80 μm.

In this comparative example, by bending deformation of the elastic member 16 a in a state pushed to the developing roller 14 a predetermined amount with respect to the elastic member 16a, it is possible to ensure a contact pressure. Specifically, the pushing amount of the developing roller 14 with respect to the elastic member 16a is set to 1.2 mm.

b2) Development roller: Dev4
The developing roller (the surface layer around the elastic layer does not contain alumina) used in this comparative example was prepared as follows. That is, a conductive silicon rubber layer 14b containing a conductive agent is provided around a core metal electrode 14a having an outer diameter of φ6 (mm), which is a conductive support. The surface layer of the silicon rubber layer 14b was coated with a urethane resin in which coarse particles and a conductive agent were dispersed as a coating layer (surface layer) by 10 μm, and the outer diameter of the entire developing roller 14 was set to φ11.5 (mm).

3) Comparative example 2
a3) Regulatory blade: BL4 (Fig. 14, α = 82 °)
It is the same as that in Comparative Example 1, and the description is omitted.

b3) Development roller: Dev3
The developing roller (the surface layer around the elastic layer contains alumina) used in this comparative example was prepared as follows. That is, a conductive rubber layer 14b containing a conductive agent is provided around a core metal electrode 14a having an outer diameter of φ6 (mm), which is a conductive support, and the outer diameter of the developing roller 14 substrate is φ11.5 ( mm). Here, as the material of the rubber layer, silicon rubber, urethane rubber, EPDM (ethylene / propylene copolymer), hydrin rubber, rubber in which these are mixed, and generally rubber can be used. In this example, a silicon rubber of 2.5 mm and a urethane layer of 10 um was formed to form a substrate 14b1.

Further, as the conductive agent, a desired resistance value can be obtained by dispersing carbon particles, metal particles, ionic conductive particles and the like, and carbon particles were used in this comparative example. Further, in order to adjust the hardness of the entire developing roller, a developing roller 14 having a desired hardness was produced by adjusting the amount of silicon rubber and the amount of silica as a filler.

Next, a colloidal alumina solution was prepared, and the developing roller substrate having the above-mentioned conductive elastic layer was dipped into the colloidal alumina solution to form an alumina surface layer of 1.5 um.

Here, the colloidal alumina solution used was prepared by stirring and mixing Nissan Chemical Industries' alumina sol solution 520 (average particle size 20 nm, boehmite) and ethanol so as to have a volume ratio of 1: 4.

Further, in this comparative example, the coatability and adhesion of the colloidal alumina solution are improved by irradiating the surface of the developing roller substrate 14b1 with UV before dipping. After forming the surface layer of alumina, it was dried at 140 ° C. for 15 minutes.

4) Comparative example 3
a4) Regulatory blade: BL1 (Fig. 4, α = 75 °)
Unlike Comparative Example 2, BL1 of Example 1 was used as the regulation blade.

b4) Development roller: Dev3
It is the same as that in Comparative Example 2, and the explanation is omitted.

5) Example 2
a5) Regulation blade: BL1 (Fig. 4, α = 75 °)
It is the same as that in the first embodiment, and the description is omitted.

b5) Development roller: Dev2
The developing roller used in this example (the surface layer around the elastic layer contains alumina and organic components and has a higher volume resistivity than the elastic layer) was prepared as follows. That is, a conductive rubber layer 14b containing a conductive agent is provided around a core metal electrode 14a having an outer diameter of φ6 (mm), which is a conductive support, and the outer diameter of the developing roller 14 substrate is φ11.5 ( mm). In this example, urethane rubber was used. Next, the alumina sol solution was prepared, and 1.5 um of an alumina coating layer was formed by dipping on the developing roller substrate having the above-mentioned conductive elastic layer.

Here, the alumina sol solution used was prepared by stirring and mixing aluminum-sec-butoxide (Al (O-sec-Bu) 3), which is an aluminum alkoxide, and isopropyl alcohol so as to have a volume ratio of 1: 9. .. Then, acetylacetone, which is a stabilizer, was mixed with aluminum alkoxide so as to have a molar ratio of 1, and the mixture was stirred at room temperature for 3 hours to prepare an alumina sol solution.

In this embodiment, the surface of the developing roller substrate is irradiated with UV before dipping to improve the coatability and adhesion of the alumina sol solution. After forming the surface layer of alumina, it was dried at 200 ° C. for 15 minutes. The organic component of the surface layer of the developing roller at this time is formed of acetylacetone and a butyl group.

6) Example 3
a6) Regulatory blade: BL2 (Fig. 6, α = 75 °)
As shown in FIG. 6, in the regulation blade 16 of this embodiment, the elastic member 16a has a bent shape. The regulation blade 16 of this embodiment has a plate-shaped elastic member 16a and a support member 16b that supports the elastic member 16a. The elastic member 16a is cantilevered and supported by the support member 16b fixed to the developing frame at the support portion. The elastic member 16a comes into contact with the developing roller 14 at the tip end portion on the free end side opposite to the support portion supported by the support member 16b.

In this configuration, the elastic members 16a developing roller 14 in contact with no load, by pushing a certain amount of the developing roller 1 4 with respect to the elastic member 16a, is pressed against the elastic member 16a to the developing roller 14. At this time, the elastic member 16a is pressed against the developing roller 14, and a predetermined pressure contact force is obtained by the elastic restoring force.

At the contact position with the developing roller 14, the regulating blade 16 contacts the developing roller 14 with the tip of the elastic member 16a on the free end side facing the upstream side in the moving direction of the developing roller 14 (counter direction). It is provided as follows. As a result, it is possible to reduce the amount of the toner carried on the developing roller 14 taken into the contact position between the elastic member 16a and the developing roller 14, and the decrease in the pressure contact force due to the powder pressure of the toner is reduced. be able to.

The elastic member 16a is a plate-shaped member made of an elastic (springy) material such as a thin metal plate such as stainless steel, phosphor bronze, or an aluminum alloy, or a thin plate made of a high-hardness conductive resin or the like. Can be used. Further, as the support member 16b, a member formed of a plate-shaped member such as a metal plate thicker than the elastic member 16a can be used. In this embodiment, the regulation blade 16 is formed by fixing an elastic member 16a made of a thin stainless steel plate having a thickness of 0.08 mm to a support member 16b obtained by bending an iron plate having a thickness of 1.2 mm into an L-shaped cross section. Is used.

Further, the elastic member 21a is provided so as to abut against the developing roller 1 4 at a predetermined angle. As with the regulation blade BL1, the angle α is provided so as to be 75 °.

Further, in this arrangement, the elastic member 16a at the tip of 3.0 mm, were bent 20 ° to the distal end side to the developing roller 1 4 direction. The shape and dimensions of the elastic member 16a are not limited to those of the present embodiment, and may be different in the position of the bent portion and the bent angle. For example, as shown in FIG. 16 (a), the elastic member 16a may be bent at least two positions in the free length direction to the tip portion from the support member 16b. Further, the elastic member 16a in FIG. 16B has a convex curved surface on the opposite side to the developing roller 14. By changing the shape of the elastic member 21a in this way, the degree of freedom in arranging the regulation blade is increased.

b6) Development roller: Dev1
It is the same as that in the first embodiment, and the description is omitted.

7) Example 4
a7) Regulatory blade: BL3 (Fig. 7, α = 75 °)
The regulation blade 16 used in this embodiment will be described with reference to FIG. Although it is basically the same as the regulation blade BL1, the elastic member 16a having a bent shape used in BL2 (Example 3) was used as the elastic member. The angle α formed at this time was set to 75 °.

b7) Development roller: Dev1
It is the same as that in the first embodiment, and the description is omitted.

(Evaluation method in each example and each comparative example)
1) Fog evaluation in a high humidity environment (initial and after durability)
Fog is an image defect in which toner is slightly developed in a white part (unexposed part) that is not originally printed and appears like a background stain. The method for evaluating the amount of fog was as follows.

The image forming apparatus is stopped during printing of a solid white image. The toner on the photoconductor after development and before transfer is once transferred to a transparent tape, and the tape to which the toner is attached is attached to a recording paper or the like. Also, attach tape without toner on the same recording paper at the same time. The optical reflectance of the tape attached to the recording paper is measured by a green filter with an optical reflectance measuring device (TC-6DS manufactured by Tokyo Denka), and subtracted from the reflectance of the tape to which no toner is attached. The amount of reflectance of the fog was calculated and evaluated as the amount of fog. The amount of fog was measured at 3 or more points on the tape and the average value was calculated.
XX: The amount of fog is 5.0 or more.

X: The amount of fog is less than 3.0 to 5.0%.

Δ: The amount of fog is less than 1.0 to 3.0%.

◯: The amount of fog is less than 1.0%.

The fog evaluation was performed in a test environment of 30 ° C., 80% RH, after printing 100 sheets and 6000 sheets, and after leaving for 24 hours. The printing test was performed by continuously passing recorded images of horizontal lines having an image ratio of 5%. Here, as the horizontal line having an image ratio of 5%, specifically, an image in which 19 dot line non-printing is repeated after 1 dot line printing is used. Further, continuous paper passing was performed at a normal speed (120 mm / sec), and fog evaluation was performed in a low speed mode (60 mm / sec). Further, the evaluation after 100 sheets of paper was set as the initial evaluation, and the image evaluation after 6000 sheets was set as the endurance.

2) Solid image density evaluation (initial and after endurance)
In the initial image density evaluation, the image forming apparatus was left in an evaluation environment of 30 ° C. and 80% Rh for one day to acclimatize to the environment, and then 100 sheets were printed and 6000 sheets were printed. The printing test of 100 sheets and 6000 sheets was carried out by continuously passing recorded images of horizontal lines having an image ratio of 5%. Here, the evaluation after 100 sheets of paper was defined as the initial evaluation, and the image evaluation after 3000 sheets was defined as after the durability. In the image evaluation, three solid black images were continuously output, 10 points on the third solid image paper surface were extracted, and the average value was taken as the solid black image density.

Here, the solid image density was determined using a spectordensiometer 500 (manufactured by X-Rite). The print test and evaluation images were monochromatic and were output at normal paper speed (120 mm / sec). Then, the evaluation was performed using the symbols ○, Δ, and × described below.

◯: 10-point average is 1.3 or more in a solid black image Δ: 10-point average is 1.1 or more and less than 1.3 in a solid black image ×: 10-point average is 1.0 or more in a solid black image , Less than 1.1 XX: In a solid black image, the average of 10 points is less than 1.0 3) Fog evaluation in a low humidity environment (initial)
Basically, it follows the evaluation method of fog in a high humidity environment, but the following points are different. The evaluation environment was 15.0 ° C., 10% RH, and paper was passed and evaluated at normal paper speed.

4) Evaluation of vertical streaks (HT streaks) of halftone images during endurance Evaluation of uniformity of halftone images during endurance is performed after leaving at 15.0 ° C. and 10% RH for 24 hours and acclimatizing to the environment. , 6000 sheets were printed. Recorded images of vertical lines with an image ratio of 5% were continuously passed through. Here, the halftone image was output at a normal paper speed (120 mm / sec) because the print test and evaluation images were monochromatic. Then, the evaluation was performed using the symbols ○ and × explained below.

◯: Vertical stripe-like shading unevenness cannot be visually recognized in the halftone image 1 and the halftone image 2.

Δ: Light and shade unevenness can be visually recognized in either the halftone image 1 or the halftone image 2.

X: Vertical line-shaped shading unevenness can be visually recognized in the halftone image 1 and the halftone image 2.

In this evaluation, the halftone image 1 records one line in the main scanning direction and then records four lines in a striped pattern, and the halftone image 2 records one line in the main scanning direction, and then two lines. It means a striped pattern that is not recorded, and expresses the density of halftones as a whole.

Furthermore, in this evaluation, the following evaluations were performed among the above evaluations ○, and those satisfying the criteria were marked with ⊚. That is, after printing 6000 sheets, 500 sheets of vertical lines having an image ratio of 1% were continuously passed to evaluate the halftone image.

⊚: Similar to the above ○ evaluation, vertical stripe-like shading unevenness cannot be visually recognized in the halftone image 1 and the halftone image 2.

5) Evaluation of fog after endurance at the time of cleanerless (after endurance)
Evaluation was also performed in a modified example of the process cartridge (FIG. 3). This evaluation is based on the above-mentioned post-durability fog evaluation.

Table 1 shows the results of each evaluation.

(Advantage of Example 1 over Comparative Example 1 which is a conventional technique)
First, the superiority of Example 1 over the prior art of Comparative Example 1 will be described. In Comparative Example 1, an increase in the amount of fog is observed. The reason for this is considered to be that the toner charge is greatly attenuated between the developing nip, and particularly after the durability, the fog amount is remarkably increased due to the attenuation of the toner charge and the decrease in the charge imparting property of the toner.

On the other hand, in Example 1, the amount of fog is suppressed through durability. That is, by forming a highly resistant surface layer on the developing roller, the attenuation of the toner charge is effectively suppressed. In particular, even when the charge imparting property of the toner is reduced after durability, the amount of fog can be suppressed because the attenuation of the toner charge between the developing nip is suppressed.

In addition, since the alumina surface layer occupied in the surface layer has a negative charge imparting property to the toner, an increase in the amount of fog can be remarkably suppressed (Fig. 11, top). As a verification, the power of the main body is turned off during solid white paper, the charge amount distribution of the toner on the developing roller is measured, and the charge of the toner on each developing roller before and after passing through the developing nip where the developing roller abuts on the photoconductor. This was done by measuring the amount distribution and evaluating the amount of change.

The lower part of FIG. 11 shows the charge distribution on the developing roller before and after passing through the developing nip where the photoconductor and the developing roller come into contact with each other when the developing roller of Comparative Example 1 is used. In Comparative Example 1, which is a conventional technique, it can be seen that the charge amount of the toner is significantly lower after passing through the contact portion than before passing through.

Regarding the horizontal axis of FIG. 11, Q is the charge amount of one toner and d is the toner particle size, which were measured by an E-SPART analyzer manufactured by Hosokawa Micron Corporation. As for the attenuation of the toner charge amount, the larger the electric field strength formed between the photoconductor and the developing roller, the larger the attenuation amount of the toner charge and the larger the fog amount. Also, as with the electric field strength, the slower the process speed, the greater the amount of toner charge attenuation and the greater the amount of fog. The reason is that the time required for the toner to pass on the developing roller increases between the contact nips where the photoconductor and the developing roller come into contact with each other, and the toner charge is further attenuated.

By the way, the initial solid image densities of Example 1 and Comparative Example 1 are both good. In the first embodiment, since the high-resistance surface layer is formed as a thin layer, the same image density as the conventional one can be obtained. On the other hand, in Comparative Example 1, the image density decreases after the durability. It is considered that the reason for this is that after the durability, the chargeability of the toner decreases, so that the transferability deteriorates, the amount of toner reaching the paper decreases, and the image density decreases.

Further, in the first embodiment, a potential difference is provided between the developing roller and the regulation blade in order to stabilize the toner coat layer on the developing roller. The potential difference is in the direction in which the negative charge is pressed toward the developing roller side, and the negative charge and the charge on the toner surface act on the developing roller side. Therefore, the toner charge is attenuated even at the blade nip where the regulation blade and the developing roller come into contact with each other, resulting in a significant decrease in the toner charge amount. As a result, the toner having a smaller amount of charge is supplied onto the drum, which makes it difficult for the toner to move in the transfer portion.

In Example 1, even when the chargeability of the toner deteriorated after durability is lowered, in addition to the charge imparting property of the alumina in the surface layer, in the developing nip that contacts the photoconductor and in the blade nip that contacts the regulation blade. The charge attenuation of the toner can also be stably suppressed. Therefore, high transferability can be maintained.

Next, the evaluation results in the modified example of the process cartridge (FIG. 3) will be described. Since the modified example of the process cartridge (FIG. 3) does not have a cleaning blade, the toner remaining on the photoconductor without being transferred is negativeized when passing through the charging roller and is collected by the developing apparatus at the developing nip. .. Further, in order to improve the recoverability of the return toner at the developing nip, the Vback is set as large as 500V. In Comparative Example 1 which is a conventional technique, since Vback is large, the toner charge is greatly attenuated when passing through the developing nip, and the amount of fog is increased.

Further, in Comparative Example 1, in addition to the large amount of fog, the amount of toner remaining without being transferred is large, so that the amount of toner reaching the contact portion between the charging roller and the photoconductor is remarkably large. Therefore, the amount of toner accumulated on the surface of the charging roller is large, and the desired charging performance cannot be obtained. As a result, for example, a density difference is generated in a halftone uniform image according to the printing history.

On the other hand, in Example 1, a good image can be obtained even in the modified example of the process cartridge (FIG. 3). The reason is that, despite the fact that the toner charge is easily attenuated when passing through the developing nip due to the large Vback, the attenuation of the toner charge can be effectively suppressed and the toner charge can be applied. is there. Therefore, the increase in the amount of fog can be remarkably suppressed, and the high transferability can be maintained, so that the toner remaining without being transferred can be suppressed, and the halftone image density fluctuation due to the charging roller stain can be suppressed.

As described above, stable and good images can be obtained, and even in a cleanerless system such as a modified example of the process cartridge (FIG. 3), the toner that cannot be transferred and remains on the photoconductor is remarkably reduced. Can be suppressed. Therefore, dirt on the charging roller can be suppressed. Further, in order to improve the recoverability, the amount of fog can be suppressed even when the Vback is set to be large, so that the toner remaining without transfer can be effectively recovered in the developing apparatus.

(Superiority of Example 1 over each comparative technique)
Next, the superiority of each embodiment will be described by comparing with the comparative technique. First, in Comparative Example 1, as described above, since the charge imparting ability is low and the charge attenuation when passing through the developing nip is large, the amount of fog increases under high humidity and the solid image density decreases due to the decrease in transferability. Comparative Example 2 is an example in which a surface layer is formed by aggregation of alumina particles in order to suppress the charging ability and the attenuation when passing through the developing nip as compared with Comparative Example 1. Therefore, as compared with Comparative Example 1, the increase in the amount of fog and the decrease in the solid image density are improved. However, the amount of fog increased in a low humidity environment.

The reason for this is considered as follows. That is, in a low humidity environment, when the amount of charge possessed by the toner is large, the toners are electrostatically attracted to each other to cause agglomeration, which is a state in which so-called electrostatic agglomeration is likely to occur. When toner aggregation is promoted, it passes through the toner regulating portion in an aggregated state. As a result, if the toner layer on the developing roller is disturbed or uncharged toner is mixed in a part of the aggregated toner, the amount of fog increases.

The regulation blade BL1 of Comparative Example 2 has a low regulation force, and when the amount of charge of the toner is high and electrostatic aggregation is likely to occur, it is difficult to form a stable toner coat layer. On the other hand, Comparative Example 3 uses the regulation blade BL1 which has a higher regulatory force than Comparative Example 2. Since BL1 can stably form edge contact, the increase in the amount of fog under low humidity is suppressed by stabilizing the toner coat layer. However, the decrease in solid image density is larger than that in Comparative Example 2.

The reason for this is that the BL1 regulatory blade, which has high regulatory power, is configured to maintain edge contact with the surface of the developing roller in order to obtain that high regulatory power, so it is thought that the surface layer of the developing roller has been scraped and thinned. Be done. As a result, it is considered that the charge imparting property of the alumina particles, which is highly charged, is reduced, the transferability is deteriorated, and the solid image density is lowered.

This means that the amount of fog under high humidity after durability is the same in Comparative Example 2 and Comparative Example 3, but in the modified example (FIG. 3) of the process cartridge in which the Vback is set to be large, Comparative Example 3 is compared with Comparative Example 2. The large increase in fog under high humidity also suggests a decrease in the film thickness of the surface layer. That is, it is considered that the resistance is lowered as the surface layer is thinned, and the effect of suppressing the amount of toner charge when passing through the developing nip cannot be obtained.

On the other hand, in Example 1, alumina and a resin are mixed in the surface layer, the abrasion resistance is high, and a high charge imparting and charge attenuation suppressing effect can be stably obtained. In particular, it is possible to stably form a toner coat layer even when a regulation blade having a high regulation force for a toner having a high charge amount is used. As a result, a stable and good image can be obtained over time and regardless of humidity.

(Comparison of each example and each comparative example regarding the vertical streak evaluation result in the halftone image under low humidity)
Next, the superiority of each example will be described by comparing the vertical streak evaluation results in the halftone image under low humidity with Examples 1 to 4 and Comparative Examples 1 to 3.

1) Comparative example 1
In Comparative Example 1, vertical streaks in the halftone image are generated. The reason is presumed as follows. The regulation blade of Comparative Example 1 has a large angle α of 82 ° and is fixedly supported by the developing apparatus. For this reason, when the toner passes through the contact portion between the regulation blade and the developing roller, the inorganic particles externally attached to the toner surface cause scraping, and the contact tip portion (edge) initially obtained from the initial contact pressure distribution. It becomes impossible to obtain a sharp contact pressure at the part) (FIG. 12 (b)).

In addition, the sharpening of the tip of the regulation blade increases the intake port and increases the amount of toner passing through. The toner transfer as shown by the black arrow in FIG. 12 depends on the adhesion between the surface of the developing roller and the toner. However, as the scraping of the regulation blade progresses, the toner uptake amount increases, but the increase in the toner transfer amount on the developing roller is small. Therefore, the toner (12N) in the vicinity of the regulation blade tends to stay, and fusion or sticking to the regulation blade occurs in the vicinity of the contact nip outlet.

In particular, in Comparative Example 1, since the conventional developing roller Dev4 has a low charging ability, the toner transfer amount is low and the toner retention is accelerated. As a result, fused substances such as toner agglomerates and agglomerates are generated on the surface of the regulation blade, streaks are generated on the toner coat layer, and vertical streaks are generated in the halftone image. Further, as shown in FIG. 12C, even in the vicinity of the inlet of the regulated blade, the regulated toner decreases due to the decrease in the conveyed amount and the increase in the taken-in amount.

Therefore, toner retention (12N) is likely to occur near the inlet of the regulation blade, toner agglomerates, blade fusion, and sticking occur, and vertical streaks in the halftone image are generated. Comparative Example 2 is an example in which an alumina surface layer having a high charge-imparting ability was formed to increase the transport amount, but the vertical streaks in the halftone image were the same as those in Comparative Example 1. The reason is that although the toner retention is suppressed by increasing the transfer amount, the increase in the transfer amount promotes the scraping of the regulation blade and causes the pressure drop region in the contact nip to expand more than in Comparative Example 1. As a result, despite the increase in the amount of toner conveyed, toner retention is formed and vertical streaks in the halftone image are generated.

Similar to Comparative Example 2, Comparative Example 3 is an example in which a developing roller having a high transfer amount is used to promote the scraping of the regulating blade. However, even if the scraping of the regulating blade is promoted, edge contact is easily formed, so that the regulating force is regulated. Does not cause a significant decrease in. The reason is that, as shown in FIG. 13B, since the angle α is as large as 75 °, the intake port does not change significantly even if the tip of the regulation blade is scraped.

In addition, as shown in FIG. 13 (c), since the regulation blade tip is swiveled 16r around the swing fulcrum, the contact portion is pressed in the scraped direction, so that the regulation force does not decrease. However, since the edge contact is continuously maintained, the wear of the surface layer of the developing roller is promoted, the transporting force is lowered in the latter half of the durability, toner retention is formed, and a slight halftone image defect occurs.

On the other hand, in Example 1, alumina and a resin are mixed in the surface layer, the abrasion resistance is high, and a high charge imparting and charge attenuation suppressing effect can be stably obtained. In particular, it is possible to stably form a toner coat layer even when a regulation blade having a high regulation force for a toner having a high charge amount is used. As a result, the toner transfer amount can be maintained high while maintaining a high regulatory force, so that halftone image defects are remarkably suppressed.

In particular, by maintaining the toner transfer amount, the action of scraping the regulating blade is also maintained. Therefore, a refreshing surface is appropriately formed on the surface of the regulating blade 16 to effectively suppress the formation of toner agglomerates and fused materials. Can be done. As a result, a stable and good image can be obtained over time and regardless of humidity.

In Example 1, when the regulation blade 16 after durability was observed, it was confirmed that the metal surface was mirrored, and there were no adhered substances or deposits, and the state was in good condition.

Here, in order to form a refreshing surface even if the tip of the regulation blade 16 is scraped and to form a stable toner coat layer, the angle α is preferably 45 ° or more and 80 ° or less as described above. More preferably, it is 75 ° or less. That is, it is more preferable to satisfy the following conditions with respect to the angle α.

45 ° ≤ α ≤ 75 °
Further, the surface hardness of the developing roller is preferably 40 ° or more and 70 ° or less. When the surface hardness exceeds 70 °, significant toner deterioration occurs, and the solid black image density and halftone image density decrease due to the deterioration of transferability. Further, when the MD1 hardness is less than 40 °, the wear of the surface layer of the developing roller deteriorates, so that it is not possible to form a stable toner coat layer and an image over time.

(Comparison in each example)
Example 2 is an example in which the surface layer is formed of alumina sol. Since the surface layer made of alumina sol has higher wear resistance than the surface layer formed by the aggregation of alumina particles of Comparative Example 2, image defects due to wear of the surface layer in the latter half of durability are improved. The third embodiment is an example in which a mage is formed in the vicinity of the tip of the regulation blade and the α value is increased in order to easily maintain the edge contact of the regulation blade. Since the regulation blade is fixed, the contact pressure changes due to scraping, so that a good image can be obtained over time, although it is slightly inferior to Example 1.

Further, the first and fourth embodiments have a swing fulcrum, and the contact pressure fluctuation is remarkably small even if the blade is scraped. As a result, a stable image can be obtained over time. Further, in the fourth embodiment, since the mage is formed in the vicinity of the tip, stable regulation can be performed even with a cheaper thin metal or a material having a low hardness.

(Further Examples)
1) Example 5
It is basically the same as Example 1, except that the following points are different. As the alumina powder, aluminum oxide (average particle size 50 nm), urethane acrylate (Arakawa Chemical Industry: Beamset 550B), and hexanediol acrylate were adjusted to have a ratio of 3: 7.

2) Example 6
It is basically the same as Example 1, except that the following points are different. As the alumina powder, aluminum oxide (average particle size 50 nm), urethane acrylate (Arakawa Chemical Industry: Beamset 550B), and hexanediol acrylate were adjusted to have a ratio of 3: 5: 2.

3) Example 7
It is basically the same as Example 1, except that the following points are different. As the alumina powder, aluminum oxide (average particle size 50 nm), urethane acrylate (Arakawa Chemical Industry: Beamset 550B), and hexanediol acrylate were adjusted to have a ratio of 3: 4: 3.

4) Example 8
It is basically the same as Example 1, except that the following points are different. The alumina powder was adjusted by appropriately diluting methyl ethyl ketone to a blending ratio of aluminum oxide (average particle size 50 nm) and epoxy acrylate (Arakawa Chemical Industry: Beamset 1200) to a weight ratio of 3/7. The prepared coating liquid was spray-coated on the above-mentioned developing roller and irradiated with ultraviolet rays (low-pressure mercury) to form a surface layer of 1.2 um.

5) Example 9
It is basically the same as Example 1, except that the following points are different. The alumina powder was adjusted by appropriately diluting isopropyl alcohol to a blending ratio of aluminum oxide (average particle size 50 nm) and polyurethane resin (Arakawa Chemical Industry: Juliano KL-593) to a weight ratio of 1/3. The prepared coating liquid was spray-coated on the above-mentioned developing roller and heated at 80 ° C. for 30 minutes to form a surface layer of 1.2 um.

(Further evaluation results of Examples 5 to 9)
a) Evaluation results of Examples 5 to 7 Examples 5 and 6 had the same evaluation results. In Example 7, vertical streaks of the halftone image were slightly generated. When the surface of the developing roller is observed by SEM and EDX, the aggregated particle size of the alumina particles is about 65 um for the roller of Example 6, about 48 um for the roller of Example 5, and the agglomerated particle size of Example 5 is clear. Could not be identified and was evenly dispersed. Since 5 um was used as the toner particle size, the particle size of alumina agglomerates with respect to the toner particle size was 9.6 times and 13 times, respectively, in Examples 5 and 6, respectively.

The reason for the aggregation of the alumina particles is considered as follows. That is, it is considered that the monomer used is liquid at room temperature and easily flows immediately after coating on the surface of the developing roller, and the flowable alumina particles around the monomer agglomerate during air drying and drying. .. The particle size of the alumina particles is preferably 100 nm or less in order to suppress the precipitation of alumina and the like in the coating liquid and to be excellent in long-term storage, and in order to reliably impart charge to the toner, the alumina particles Is preferably formed with a particle size of 30 nm or more or agglomerates.

When the regulated blade after durability was observed in Example 6, unevenness of about the above alumina agglomeration size was observed in the longitudinal direction of the regulated blade. The above is inferred as follows. That is, it is considered that the toner on the developing roller has a partially different charging ability and an adhesive force in consideration of electrostatic adhesion between the alumina portion and the resin portion. Therefore, it is considered that the easy-to-move area and the hard-to-move area on the developing roller become apparent when the toner deteriorates in the latter half of the durability. As a result, the flow of toner changed in the longitudinal direction, and it is considered that the method of scraping the regulation blade was different.

From the above, in order to form a uniform flow of toner in the longitudinal direction for the regulated blade, the particle size of alumina agglomerates (aggregate diameter or volume average particle size) with respect to the toner particle size (toner volume average particle size). Is preferably 10 times or less. And it is more preferable that it is in a uniformly dispersed state. Further, even if the alumina particle size is uniform, if the alumina particle size exceeds 10 times the toner particle size, it is difficult to form a uniform flow of toner in the longitudinal direction as described above. Therefore, the alumina particle size used is 10 of the toner particle size. More preferably, it is twice or less.

b) Evaluation result of Example 8 Differences in evaluation result from Example 1 will be described. In Example 8, as compared with Example 1, the fog and the solid image density after durability were slightly reduced. It is considered that the reason for this is that the surface hardness (MD-1) is as high as 80 ° and the deterioration of the toner is promoted. Therefore, it is preferable to use urethane acrylic resin in order to have abrasion resistance and suppress the surface hardness from becoming extremely high.

c) Evaluation result of Example 9 Differences in evaluation result from Example 1 will be described. In Example 9, the amount of fog and the solid density image under high humidity were slightly deteriorated as compared with Example 1. It is considered that the reason is that there is a lot of urethane on the surface of alumina. By observing the surfaces of the developing rollers of Examples 1 and 9, the developing rollers of Example 9 are covered with resin, and the shape of the alumina particles can be clearly confirmed in the developing rollers of Example 1. That is, it is preferable to use a urethane acrylic resin in order to express alumina and effectively obtain the characteristics of alumina.

(Modification example)
In the above-described embodiment, the preferred embodiment of the present invention has been described, but the present invention is not limited to this, and various modifications can be made within the scope of the present invention.

(Modification example 1)
In the above-described embodiment, the process cartridge 11 is integrally provided with the photoconductor unit 18 and the developing device 4 as a developing unit, and can be attached to and detached from the image forming apparatus main body, but the present invention is limited to this. I can't. The process cartridge 11 may be divided into a photoconductor unit 18 and a developing device 4 as a developing unit as a two-body structure, and at least one of them may be detachable from the image forming apparatus main body.

Further, the developing apparatus according to the above-described embodiment may be provided not in the process cartridge but in the apparatus main body of the image forming apparatus that does not use the process cartridge.

14 ... Development roller, 14b ... Elastic layer, 16 ... Regulatory blade, 16a ... Thin plate elastic member, 16d ... Pressurized spring

Claims (20)

In order to develop the electrostatic latent image formed on the image carrier, a developer carrier that carries a developer and a developer carrier that supports the developer,
An elastic member supported by a support member is provided so as to come into contact with the developer carrier, and the tip of the elastic member is brought into contact with the developer carrier so as to face upstream in the rotational direction of the developer carrier. A developer regulating member that regulates the amount of the developer supported on the developer carrier by contact with the developer.
An urging means for pressing the developer regulating member against the developer carrier, and
In a developing device with
The developer carrier has an elastic layer and a surface layer formed around the elastic layer, containing alumina and an organic component, and having a higher volume resistivity than the elastic layer.
It is supported by the support member of the elastic member in the direction connecting the contact position between the developer carrier and the elastic member and the rotation center of the developer carrier when viewed from the axial direction of the developer carrier. When the angle formed by the direction extending from the other end side to the one end side in contact with the developer carrier is α.
A developing apparatus characterized by satisfying the condition of 45 ° ≤ α ≤ 80 °. In order to develop the electrostatic latent image formed on the image carrier, a developer carrier that carries a developer and a developer carrier that supports the developer,
Wherein comprising a supported resilient member supporting member so as to contact the developer carrying member, by abutment in the rotation direction of the developer carrying member so as to face toward the upstream side in the developer carrying member, wherein A developer regulating member that regulates the amount of the developer supported on the developer carrier at the contact position between the developer carrier and the elastic member, and a developer regulating member.
An urging means for pressing the developer regulating member against the developer carrier, and
In a developing device with
The developer carrier has an elastic layer and a surface layer formed around the elastic layer, containing alumina and an organic component, and having a higher volume resistivity than the elastic layer.
When viewed from the axial direction of the developer carrier,
A point P where an extended surface of the end surface of the elastic member on the distal end side and an extended surface of the facing surface facing the developer carrier connected to this surface intersect, and a rotation center Q of the developer carrier. And, while setting the straight line PQ connecting with and, to be the shortest,
When the angle formed by the straight line PQ and the direction extending from the other end side of the elastic member supported by the support member to the one end side in contact with the developer carrier is α.
A developing apparatus characterized by satisfying the condition of 45 ° ≤ α ≤ 80 °. The developing apparatus according to claim 1 or 2, wherein the organic component is a resin, and the alumina is composed of particles. The developing apparatus according to claim 3, wherein the resin is a urethane acrylic resin. The developing apparatus according to any one of claims 1 to 4, wherein the volume resistivity of the surface layer is 109 Ω · cm or more and 1014 Ω · cm or less. Any of claims 1 to 5, wherein the average hardness of the developer carrier is 45 ° to 70 ° (AskerC), and the hardness of the surface layer (MD-1 type) is 35 ° to 70 °. The developing apparatus according to item 1. The developing apparatus according to any one of claims 1 to 6, wherein the elastic member has a bent shape between the contact position and a position opposite to the contact position. The developing apparatus according to any one of claims 1 to 7, further comprising a support member that cantilevers and supports a position of the elastic member opposite to the contact position. The support member is rotatably provided and
The development according to claim 8, wherein the distance from the rotation center to the center of the developer carrier is set longer than the distance from the rotation center of the support member to the contact position. apparatus. The developing apparatus according to any one of claims 1 to 9, wherein the aggregate diameter or volume average particle diameter of the alumina is 10 times or less the volume average particle diameter of the developing agent. The developing apparatus according to any one of claims 1 to 10, wherein the developing apparatus satisfies the following conditions.
45 ° ≤ α ≤ 75 ° The developing apparatus according to any one of claims 1 to 11, further comprising a container for accommodating the developing agent. The developing apparatus according to any one of claims 1 to 12, wherein the elastic member is made of metal. As the support member, the metal plate having a bent first surface and a second surface is provided, the developer regulating member is supported on the first surface, and the urging means is attached on the second surface. The developing apparatus according to claim 9, wherein the developing apparatus receives power. The developing frame has a swinging fulcrum shaft that rotatably supports the developer regulating member.
The urging means is provided along the direction in which the developer regulating member extends toward the developer carrier.
The developing apparatus according to claim 14, wherein the support member is attached to a swing frame body supported by the swing fulcrum shaft. A process cartridge having an image carrier and the developing apparatus according to any one of claims 1 to 15, which can be attached to and detached from the apparatus main body of the image forming apparatus. Image carrier and
The developing apparatus according to any one of claims 1 to 15.
16 is provided in the process cartridge according to claim 16 or in the main body of the image forming apparatus that does not use the process cartridge.
Further, an image forming apparatus comprising an exposure apparatus for forming an electrostatic latent image on the image carrier. The 17th aspect of claim 17, wherein the image carrier has a transfer means for transferring the developer to a material to be transferred, and the transfer residual developer remaining on the image carrier is recovered by the developing apparatus. Image forming device. An image carrier that carries an electrostatic latent image and
A developer carrier that carries a developer, contacts the image carrier, and develops the electrostatic latent image with the developer.
A developer regulating member for regulating the amount of the developer supported on the developer carrier, and a developer regulating member.
In the image forming apparatus having
The developer carrier has an elastic layer and a surface layer formed around the elastic layer, containing alumina and an organic component, and having a higher volume resistivity than the elastic layer.
The developer regulating member cantilevers at least an elastic member whose tip on one end abuts on the developer carrier and the other end on the opposite side of the abutting portion which abuts on the developer carrier. Has a supporting member to support
The elastic member counter-contacts with respect to the moving direction of the surface of the developer carrier.
It is supported by the support member of the elastic member in the direction connecting the contact position between the developer carrier and the elastic member and the rotation center of the developer carrier when viewed from the axial direction of the developer carrier. An image forming apparatus having an angle of 45 to 80 degrees from the other end side to the one end side in contact with the developer carrier. An image carrier that carries an electrostatic latent image and
A developer carrier that carries a developer, contacts the image carrier, and develops the electrostatic latent image with the developer.
A developer regulating member for regulating the amount of the developer supported on the developer carrier, and a developer regulating member.
In the image forming apparatus having
The developer carrier has an elastic layer and a surface layer formed around the elastic layer, containing alumina and an organic component, and having a higher volume resistivity than the elastic layer.
The developer regulating member cantilevers at least an elastic member whose tip on one end abuts on the developer carrier and the other end on the opposite side of the abutting portion which abuts on the developer carrier. Has a supporting member to support
When the elastic member counter-contacts the moving direction of the surface of the developer carrier and is viewed from the axial direction of the developer carrier,
A point P where an extended surface of the end surface of the elastic member on the distal end side and an extended surface of the facing surface facing the developer carrier connected to this surface intersect, and a rotation center Q of the developer carrier. And, while setting the straight line PQ connecting with and, to be the shortest,
An image characterized in that an angle formed by the straight line PQ and a direction extending from the other end side of the elastic member supported by the support member to one end side in contact with the developer carrier is 45 to 80 degrees. Forming device.