JP2004157576A - Developing roller, developing apparatus, process cartridge and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve electrostatic latent image developing quality by preventing a toner filming. <P>SOLUTION: A roller part 21 formed in the outer peripheral part of a core bar 18 has a two-layer structure constituted of at least a conductive elastic inner layer 19 and an induction surface layer 20 as an outermost layer, and the roller part is provided with projecting and recessed parts formed by adding an additive on the surface of the surface layer 20 of the developing roller 12 for adsorbing one-component toner. Accordingly, the one-component toner adsorbed in the recessed part never being pressed and hardened by the contact with another member, even if it is not consumed, the toner is prevented from firmly sticking to the surface layer 20 of the developing roller 12. Besides, the one-component toner adsorbed to the projecting part is easily recovered, even if not consumed, the toner is prevented from firmly sticking to the surface layer 20 of the developing roller 12. Then, the same one-component toner is never adsorbed in the same position of the developing roller 12, the occurrence of toner-filming is prevented, and the electrostatic latent image developing quantity is improved. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to an electrophotographic developing device for developing an electrostatic latent image formed on a latent image carrier such as a photoreceptor with one-component toner, a developing roller used for the electrophotographic developing device, and a developing device. And an image forming apparatus.

  Electrophotographic image formation involves uniformly charging the surface of a photoreceptor, which is a latent image carrier, exposing it to form an electrostatic latent image, adsorbing toner to the electrostatic latent image, and developing the latent image. This is performed using an electrophotographic process of transferring and fixing a toner image to a recording medium. As one of the systems for adsorbing toner to an electrostatic latent image on the surface of a photoreceptor to develop and visualize the image, a one-component contact development system using one-component toner is generally used. Next, an example of this method will be described.

  In the one-component contact developing method, in order to develop an electrostatic latent image on the surface of a photoconductor, a one-component toner is conveyed to a latent image on the surface of the photoconductor by a developing roller while being attracted. The developing roller has an inner layer on a cored bar, and is formed by coating a surface layer on the inner layer.

  More specifically, a developing roller and a replenishing roller rotating in the same direction while being pressed against the developing roller with a predetermined bite amount frictionally charge the one-component toner at a replenishing roller nip portion that is a contact portion. As a result, the triboelectrically charged one-component toner is attracted to the surface layer of the developing roller due to the potential difference between the developing roller and the supply roller. Further, the one-component toner adsorbed on the surface layer of the developing roller further frictionally develops in a blade nip portion which is a contact portion between the developing roller and a developing blade provided in contact with the surface of the developing roller with a predetermined bite amount. Be charged. In addition, the frictionally charged one-component toner is supplied to the photoreceptor side while the thickness of the toner layer is regulated by the developing blade, and is attracted to the surface layer of the developing roller due to a potential difference between the developing roller and the developing blade. Thereafter, one-component toner of the surface layer of the developing roller is attracted to the electrostatic latent image on the surface of the photoconductor by a potential difference between the developing roller and the photoconductor at a photoconductor nip portion which is a contact portion between the developing roller and the photoconductor. Thereby, the electrostatic latent image is developed and visualized.

  However, since the one-component toner used in the one-component contact developing method is melted by a small amount of heat, the surface layer of the developing roller that is adsorbing the one-component toner has the above-described supply roller nip portion, blade nip portion, and photoconductor nip. Due to strong contact with other members in a part or the like, the one-component toner may be melted by frictional heat and compacted, and may be fixed to the surface layer of the developing roller with time. This sticking phenomenon is called toner filming. In particular, in a place where the same one-component toner is always adsorbed without consuming one-component toner, such as a surface layer of a developing roller facing an end of the photoreceptor where an electrostatic latent image is hardly formed. This toner filming appears remarkably. Such toner filming that occurs on the surface layer of the developing roller is a factor in generating an abnormal image such as a decrease in density and background contamination in the development of an electrostatic latent image.

  An object of the present invention is to provide a developing roller, a developing device, a process cartridge, and an image forming apparatus capable of preventing toner filming and improving the development quality of an electrostatic latent image.

  The roller according to claim 1, wherein the developing roller has at least a two-layer structure including an inner layer that is an elastic layer having conductivity and is elastically deformable, and a surface layer that is an outermost layer and a dielectric layer. Was provided on the outer peripheral portion of the cored bar, and an additive was added to the surface layer in order to form the surface of the surface layer into irregularities in the developing roller that adsorbs the one-component toner.

  Therefore, since the surface of the surface layer of the developing roller has irregularities formed by the addition of the additive, the one-component toner adsorbed in the concave portion is compacted by contact with other members even if it is not consumed. It does not adhere to the surface layer of the developing roller. In addition, the one-component toner adsorbed on the convex portion is easily collected even if not consumed, and does not adhere to the surface layer of the developing roller. As a result, the same one-component toner is not always attracted to the same portion of the developing roller, and the occurrence of toner filming is prevented.

  According to a second aspect of the present invention, in the developing roller according to the first aspect, the average particle diameter of the additive is 5 μm or more and 100 μm or less.

  Therefore, the average particle size of the additive is regulated to 5 μm or more and 100 μm or less, so that the average particle size of the additive is maintained at a value suitable for preventing occurrence of toner filming.

  According to a third aspect of the present invention, in the developing roller according to the first or second aspect, the additive is nylon-based particles.

  Accordingly, since the additive is made of nylon-based particles, occurrence of toner filming can be prevented at low cost.

  According to a fourth aspect of the present invention, in the developing roller according to the first or second aspect, the additive is silicon-based particles.

  Therefore, since the additive is silicon-based particles, the triboelectric charging performance to the one-component toner is improved, and the occurrence of toner filming is prevented.

  The roller according to claim 5, wherein the developing roller has at least a two-layer structure of an inner layer that is an elastic layer having conductivity and is elastically deformable, and a surface layer that is an outermost layer and is a dielectric layer. Was provided on the outer peripheral portion of the cored bar, and the surface of the inner layer was subjected to uneven processing in order to form the surface of the surface layer as uneven in a developing roller that adsorbs the one-component toner.

  Therefore, the surface of the surface layer of the developing roller has irregularities formed by processing the surface of the inner layer, so that the one-component toner adsorbed in the concave portions is in contact with other members even if not consumed. And is not fixed to the surface layer of the developing roller. In addition, the one-component toner adsorbed on the convex portion is easily collected even if not consumed, and does not adhere to the surface layer of the developing roller. As a result, the same one-component toner is not always attracted to the same portion of the developing roller, and the occurrence of toner filming is prevented.

  According to a sixth aspect of the present invention, in the developing roller according to the fifth aspect, the JIS 10-point average roughness of the surface of the inner layer is 5 μm or more and 100 μm or less.

  Therefore, the JIS 10-point average roughness of the surface of the inner layer is regulated to 5 μm or more and 100 μm or less, so that the JIS 10-point average roughness of the surface of the inner layer is maintained at a value suitable for preventing toner filming. .

  According to a seventh aspect of the present invention, there is provided a developing device according to any one of the first to sixth aspects, wherein the developing roller is disposed at a position in contact with a latent image carrier for forming an electrostatic latent image. A developing blade that elastically abuts on the surface of the developing roller at a position in the rotation direction upstream of the pressure contact portion with the image carrier to regulate the thickness of the toner layer while frictionally charging the one-component toner.

  Accordingly, the thickness of the toner layer is regulated by the developing blade elastically in contact with the surface of the developing roller, and the one-component toner is supplied to the pressure contact portion between the developing roller and the latent image carrier while being charged by friction. In this case, since the surface layer of the roller portion of the developing roller has irregularities, the one-component toner is not pressed and fixed to the developing blade, the latent image carrier, or the like over time. As a result, occurrence of toner filming on the surface layer of the developing roller is prevented, and occurrence of an abnormal image due to a decrease in density in developing the electrostatic latent image and background contamination is prevented.

  According to another aspect of the present invention, there is provided a process cartridge, a latent image carrier, a charging device for uniformly charging the surface of the latent image carrier, and a developing device for developing an electrostatic latent image formed on the latent image carrier. Item 7. The developing device according to Item 7.

  Accordingly, the electrostatic latent image formed on the surface of the latent image carrier uniformly charged by the charging device is developed by the developing device using the one-component toner. In this case, since the surface layer of the roller portion of the developing roller provided in the developing device has irregularities, the one-component toner is hardened on the developing blade or the latent image carrier and fixed over time. Absent. As a result, occurrence of toner filming on the surface layer of the developing roller is prevented, and occurrence of an abnormal image due to a decrease in density in developing the electrostatic latent image and background contamination is prevented.

  According to a ninth aspect of the present invention, there is provided an image forming apparatus comprising: a latent image carrier; a charging device for uniformly charging the surface of the latent image carrier; An image exposure device for forming a latent image, a developing device for developing an electrostatic latent image formed on the latent image carrier, and a transfer device for transferring a developed image from the latent image carrier to a recording medium. And a fixing device for fixing the developed image transferred to the recording medium.

  Accordingly, the electrostatic latent image formed by the exposure of the image exposure device after the charging device uniformly charges the surface of the latent image carrier is developed by the developing device using one-component toner. In this case, since the surface layer of the roller portion of the developing roller provided in the developing device has irregularities, the one-component toner is hardened on the developing blade or the latent image carrier and fixed over time. Absent. As a result, occurrence of toner filming on the surface layer of the developing roller is prevented, and occurrence of an abnormal image due to a decrease in density in developing the electrostatic latent image and background contamination is prevented. As a result, the development quality of the electrostatic latent image is improved.

  According to the developing roller of the present invention, since the surface of the surface layer of the developing roller has irregularities formed by the addition of the additive, even if the one-component toner adsorbed on the concave portion is not consumed, other members are not used. The one-component toner adsorbed on the projections is not easily fixed to the surface layer of the developing roller, even if the one-component toner is not consumed, so that the toner does not stick to the surface layer of the developing roller. It is possible to prevent the same one-component toner from adsorbing to the same portion of the developing roller, thereby preventing the occurrence of toner filming.

  According to the second aspect of the present invention, in the developing roller according to the first aspect, the average particle diameter of the additive is regulated to 5 μm or more and 100 μm or less. Can be maintained at a suitable value.

  According to the third aspect of the present invention, in the developing roller according to the first or second aspect, since the additive is made of nylon-based particles, the occurrence of toner filming can be prevented at low cost.

  According to the fourth aspect of the invention, in the developing roller according to the first or second aspect, since the additive is made of silicon-based particles, the triboelectric charging to the one-component toner can be improved, and the toner filming can be improved. Occurrence can be prevented.

  According to the developing roller according to the fifth aspect of the present invention, since the surface of the surface layer of the developing roller has irregularities formed by processing the surface of the inner layer, the one-component toner adsorbed on the concave portion is consumed even if it is. At least, the one-component toner adsorbed on the protrusions is easily collected even if it is not consumed, so that it is easily fixed to the surface layer of the developing roller. And the same one-component toner is always prevented from being attracted to the same portion of the developing roller, and the occurrence of toner filming can be prevented.

  According to the sixth aspect of the invention, in the developing roller according to the fifth aspect, the JIS 10-point average roughness of the surface of the inner layer is regulated to 5 μm or more and 100 μm or less. The value can be maintained at a value suitable for preventing occurrence of toner filming.

  According to the developing device of the present invention, the developing roller and the latent image carrier are controlled while the thickness of the toner layer is regulated by the developing blade elastically contacting the surface of the developing roller. When the toner is supplied toward the pressure contact portion of the developing roller, the surface layer of the roller portion of the developing roller has irregularities, so that the one-component toner is pressed and fixed on the developing blade, the latent image carrier, and the like over time. This prevents the occurrence of toner filming on the surface layer of the developing roller, thereby preventing the occurrence of an abnormal image due to a decrease in the density of the electrostatic latent image during development and a background stain.

  According to the process cartridge of the present invention, when the electrostatic latent image formed on the surface of the latent image carrier uniformly charged by the charging device is developed by the developing device using the one-component toner, Since the surface layer of the roller portion of the developing roller provided in the apparatus has irregularities, the one-component toner is not compacted on the developing blade or the latent image carrier and fixed over time, and the developing roller , The occurrence of toner filming on the surface layer can be prevented, and the occurrence of an abnormal image due to a decrease in density in developing an electrostatic latent image or background contamination can be prevented.

  According to the image forming apparatus of the ninth aspect, after the charging device uniformly charges the surface of the latent image carrier, the electrostatic latent image formed by the exposure of the image exposure device is developed by the developing device using one-component toner. In the case of development, since the surface layer of the roller portion of the developing roller provided in the developing device has irregularities, the one-component toner is pressed and fixed on the developing blade, the latent image carrier, and the like over time. This prevents the occurrence of toner filming on the surface layer of the developing roller, prevents the occurrence of an abnormal image due to a decrease in the density of the electrostatic latent image during development and the occurrence of abnormal images due to background contamination, and improves the development quality of the electrostatic latent image. Can be achieved.

  A first embodiment of the present invention will be described with reference to FIGS. This embodiment is an example in which the present invention is applied to a copying machine 1 as an image forming apparatus. FIG. 1 is a schematic diagram illustrating an internal configuration of a copying machine 1 according to the present embodiment. As shown in FIG. 1, the copying machine 1 is provided with a paper passing path 3 for connecting a paper feeding device 2 for storing transfer paper P as a recording medium and a paper discharging unit (not shown). A process cartridge 4, a transfer device 5, and a fixing device 6 are provided therein.

  FIG. 2 is a schematic diagram mainly showing the process cartridge 4 of the copying machine 1. As shown in FIG. 2, the process cartridge 4 mainly includes a drum-shaped photosensitive member 7 serving as a latent image carrier that is driven to rotate clockwise. Around the photosensitive member 7, a roller charging type charging device 8 for uniformly charging the photosensitive member 7 to −750 V, and a one-component developing type developing device using a non-magnetic one-component toner T (hereinafter referred to as “toner T”) 9, a cleaning device 10 is arranged in order.

  Above the process cartridge 4, there is provided an image exposure device 11 for irradiating the exposure position EX with a light beam to set the charging potential of -750V to about -50V to form an electrostatic latent image.

  Next, the developing device 9 will be described. The developing device 9 is disposed at a position where the developing device 9 is pressed against the surface of the photoconductor 7 with a predetermined bite amount and is driven to rotate counterclockwise in a direction opposite to the photoconductor 7, A replenishing roller 13 which is disposed at a position where the toner T is pressed against and is rotated counterclockwise in the same direction as the developing roller 12 to replenish the toner T onto the surface of the developing roller 12; A developing blade 14 provided at a position where the developing blade 14 elastically contacts with a predetermined bite amount is disposed in a developing container 15. In this case, the linear velocity ratio between the developing roller 12 and the supply roller 13 is set to 1: 1.5, and the linear velocity of the supply roller 13 is set higher.

  A bias potential is appropriately applied to the developing roller 12 by a developing bias power source 16, and a bias potential is appropriately applied to the replenishing roller 13 and the developing blade 14 by a replenishing developing bias power source 17. In this case, the charging potential by the developing bias power supply 16 is set to -400V, and the charging potential by the replenishment developing bias power supply 17 is set to -650V.

  Next, the developing roller 12 will be described. Here, FIG. 3 is a sectional view showing the developing roller 12. As shown in FIG. 3, the developing roller 12 has a two-layer structure including a metal core 18 made of metal such as stainless steel, and an inner layer 19 and a surface layer 20 provided on an outer peripheral portion of the metal core 18. And a roller portion 21 to be formed. Hereinafter, the inner layer 19 and the surface layer 20 constituting the two layers will be described.

The inner layer 19 plays a role as an elastic layer for securing elasticity necessary for preventing an excessive increase in torque at the time of contact with the photoconductor 7. For this reason, the inner layer 19 is formed of a soft material having an elasticity of about 40 ° in terms of rubber equivalent hardness (JIS-A hardness) and having a small variation in electrical characteristics such as resistance. Specific examples of the forming material include silicon rubber and urethane rubber. In this embodiment, silicon rubber is used as a forming material. The thickness of the inner layer 19 is about 4 mm. The inner layer 19 appropriately contains carbon black for imparting conductivity, and is set, for example, to have a resistance value of 10 ⁸ Ω · cm.

The surface layer 20 functions as a dielectric layer, which is the outermost layer that conveys the toner T toward the photoreceptor 7 while performing frictional charging of the toner T. It is formed with. Further, it is required that the forming material is a material that does not contaminate the photoreceptor 7 with oil or the like and has a small variation in electrical characteristics such as resistance. For this reason, the surface layer 20 is formed of a hard material having a rubber equivalent hardness (JIS-A hardness) of about 60 °, which is relatively lower in elasticity than the inner layer 19. Specific examples of the forming material include a urethane resin, a silicone resin, and a fluorine resin. In this embodiment, a urethane resin is used as a forming material. Further, an additive having an average particle size of about 5 to 100 μm is added to the urethane resin as a material for forming the resin. Examples of the additive include nylon-based particles and silicon-based particles. In this embodiment, silicon-based particles of 5 μm are used. By applying the urethane resin to which such silicon-based particles are added to the inner layer 19, the surface layer 20 is formed into a thin layer having a thickness of about 10 μm with irregularities on the surface. The resistance value of the surface layer 20 is set to, for example, 10 ⁸ Ω · cm.

  The replenishing roller 13 is formed by arranging a sponge-like inner layer made of urethane, silicon or the like on the outer peripheral portion of a metal core, and covering the soft surface of the inner layer with a resin.

  A process of forming an image on the transfer sheet P in such a configuration will be described. First, the photoreceptor 7 is uniformly charged to -750 V by the charging of the roller charging system by the charging device 8. Subsequently, at the exposure position EX of the uniformly charged photoconductor 7, a light beam corresponding to image information is irradiated from the image exposure device 11 to form an electrostatic latent image. That is, the charged potential of the light beam irradiated portion is about -50 V, and an electrostatic latent image is formed by generating a potential difference between the portion not irradiated with the light beam and the irradiated portion. Next, the electrostatic latent image formed on the photoconductor 7 travels to a contact portion with the developing device 9.

  In the developing device 9, the toner T is pumped up by the supply roller 13 in the developing container 15 and supplied to the surface of the developing roller 12. In this case, the supply roller 13 rotates in the same direction as the developing roller 12 while being pressed against the developing roller 12 and biting. At this time, the developing roller 12 and the replenishing roller 13 rub against each other with a linear velocity difference, so that the toner T is triboelectrically charged to the negative electrode. Further, the toner T is rubbed and supplied while being attracted to the surface of the developing roller 12 having a low potential by the bias potential difference (250 V) between the developing roller 12 and the replenishing roller 13.

  The toner T supplied to the developing roller 12 is conveyed toward the contact portion with the photoconductor 7 while the toner layer thickness is regulated into a thin layer state when passing through the developing blade 14 with the rotation of the developing roller 12. You. In this case, since the toner T is frictionally charged to the negative electrode by the contact between the developing roller 12 and the developing blade 14, the charge amount of the toner T further increases. In addition, due to the bias potential difference (250 V) between the developing roller 12 and the developing blade 14, the toner T is conveyed while being attracted to the surface of the developing roller 12 having a lower potential.

  Next, at a contact portion between the photoconductor 7 and the developing roller 12, the toner T has a lower potential from the developing roller 12 due to a bias potential difference (350 V) between the electrostatic latent image formed on the surface of the photoconductor 7 and the developing roller 12. The electrostatic latent image is sucked onto the electrostatic latent image, developed and visualized.

  Here, in the present embodiment, since the surface of the surface layer 20 of the developing roller 12 is processed into irregularities by adding an additive, the developing roller is not attracted onto the electrostatic latent image on the photoconductor 7. The toner T remaining in the concave portion on the developing roller 12 is not pressed and hardened, and the toner T remaining on the convex portion on the developing roller 12 is easily collected, so that the toner T does not adhere to the developing roller 12. Further, the toner T that has entered the concave portion is scraped out by the replenishing roller 13 that is pressed against the developing roller 12 and bites. As a result, the same toner T does not always adhere to the same portion of the developing roller 12, and the occurrence of toner filming is prevented. As a result, during the development of the electrostatic latent image, the occurrence of an abnormal image due to a decrease in density or background contamination is prevented, and the development quality of the electrostatic latent image is improved.

  Thereafter, in the transfer device 5, the visualized toner image on the surface of the photoconductor 7 is sucked by the potential difference, and the toner image is transferred to the transfer paper P. Further, in the cleaning device 10, the toner T remaining on the photoconductor 7 after the transfer process is scraped off and cleaned. After the transfer, the unfixed toner adhered to the transfer paper P is fixed by the heating / pressing action in the fixing device 6 arranged on the downstream side in the paper passing path 3. As a result, an image is formed on the transfer paper P.

  Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those described in the first embodiment of the present invention are denoted by the same reference numerals, and description thereof will be omitted. FIG. 4 is a cross-sectional view illustrating the developing roller 22. As shown in FIG. 4, only the roller portion 25 of the developing roller 22 of the present embodiment is different from the above-described first embodiment of the present invention.

  The developing roller 22 includes a metal core 18 made of a metal such as stainless steel, and a roller portion 25 provided on an outer peripheral portion of the metal core 18 and having an inner layer 23 and a surface layer 24 to form a two-layer structure. It is configured. Hereinafter, the inner layer 23 and the surface layer 24 constituting the two layers will be described.

The inner layer 23 plays a role as an elastic layer for securing elasticity necessary for preventing an excessive increase in torque at the time of contact with the photoconductor 7. For this reason, the inner layer 23 is formed of a soft material having an elasticity of about 40 ° in terms of rubber equivalent hardness (JIS-A hardness) and having a small variation in electrical characteristics such as resistance. Specific examples of the forming material include silicon rubber and urethane rubber. In this embodiment, silicon rubber is used as a forming material. Further, the inner layer 23 is formed by molding silicon rubber in a mold in which the inner wall is processed to have irregularities of about 5 to 100 μm (JIS 10-point average roughness, R _Z ), so that the surface has irregularities and the layer thickness is reduced. It is formed to about 4 mm. Here, it is assumed that “R _Z = 5 μm”. The inner layer 23 appropriately contains carbon black for imparting conductivity, and is set to have a resistance of, for example, 10 ⁸ Ω · cm.

The surface layer 24 functions as a dielectric layer, which is the outermost layer that conveys the toner T toward the photoreceptor 7 while performing frictional charging of the toner T. Therefore, the surface layer 24 is excellent in triboelectricity and releasability of the toner T. It is formed with. Further, it is required that the forming material is a material which does not contaminate the photoreceptor 7 with oil or the like and has a small variation in electrical characteristics such as resistance. For this reason, the surface layer 24 is formed of a hard material having a rubber equivalent hardness (JIS-A hardness) of about 60 °, which is relatively lower in elasticity than the inner layer 23. Specific examples of the forming material include a urethane resin, a silicone resin, and a fluorine resin. In this embodiment, a urethane resin is used as a forming material. By applying such a urethane resin on the inner layer 23, the surface layer 24 is formed as a thin layer by coating with a layer thickness of about 10 μm. In this case, since the surface of the inner layer 23 has irregularities, the surface layer 24 also has similar irregularities on its surface. The resistance value of the surface layer 24 is set to, for example, 10 ⁸ Ω · cm.

  Therefore, by the unevenness processing of the surface of the surface layer 24, the same operation and effect as in the first embodiment of the present invention described above can be obtained in this embodiment as well.

  In each of the embodiments, a non-magnetic one-component toner is used. However, the present invention is not limited to this, and there is no problem even if a magnetic one-component toner is used.

  Further, in each of the embodiments, the drum-shaped photoconductor is used as the latent image carrier. However, the present invention is not limited to this, and there is no problem even if the belt-shaped photoconductor is used as the latent image carrier.

Next, several tests were conducted on the toner concentration of the remaining toner filmed on the developing roller by changing the surface roughness (JIS 10-point average roughness, _RZ ) of the surface layer of the developing roller due to unevenness processing. The results are shown in Table 1 as examples.

  The toner density was measured using a Macbeth densitometer after peeling off the toner remaining on the toner filmed portion on the developing roller after printing out 3,000 images. If the toner density is 0.1 or less, the toner density is within a range that does not affect the image due to toner filming.

  As shown in Table 1, when the surface roughness of the surface layer of the developing roller was regulated to “RZ = 5 μm” or more, the toner concentration was found to be 0.1 or less.

1 is a schematic diagram illustrating an internal configuration of a copying machine according to a first embodiment of the present invention. FIG. 2 is a schematic diagram mainly showing a process cartridge of the copying machine. FIG. 3 is a cross-sectional view illustrating a developing roller. FIG. 7 is a cross-sectional view illustrating a developing roller according to a second embodiment of the present invention.

Explanation of reference numerals

Reference Signs List 5 transfer device 6 fixing device 7 latent image carrier 8 charging device 9 developing device 11 image exposure device 12, 22 developing roller 14 developing blade 18 core metal 19, 23 inner layer 20, 24 surface layer 21, 25 roller portion P recording medium T One-component toner

Claims (9)

A roller having at least a two-layer structure of an inner layer, which is an elastically deformable elastic layer having conductivity, and a surface layer, which is an outermost layer, is provided on the outer peripheral portion of the core bar. In the developing roller that absorbs the component toner,
A developing roller, wherein an additive is added to the surface layer so as to form the surface of the surface layer with irregularities.   2. The developing roller according to claim 1, wherein the additive has an average particle size of 5 μm or more and 100 μm or less.   3. The developing roller according to claim 1, wherein the additive is nylon-based particles.   3. The developing roller according to claim 1, wherein the additive is silicon-based particles. A roller having at least a two-layer structure of an inner layer, which is an elastically deformable elastic layer having conductivity, and a surface layer, which is an outermost layer, is provided on the outer peripheral portion of the core bar. In the developing roller that absorbs the component toner,
A developing roller, characterized in that the surface of the inner layer is processed to be uneven so that the surface of the surface layer is made uneven.   6. The developing roller according to claim 5, wherein the JIS 10-point average roughness of the surface of the inner layer is 5 μm or more and 100 μm or less. The developing roller according to any one of claims 1 to 6, wherein the developing roller is arranged at a position where the developing roller is pressed against a latent image carrier that forms an electrostatic latent image.
A developing blade that elastically abuts against the surface of the developing roller at a rotational position upstream from a pressure contact portion between the developing roller and the latent image carrier, and regulates a toner layer thickness while frictionally charging a one-component toner;
A developing device comprising: A latent image carrier,
A charging device for uniformly charging the surface of the latent image carrier,
The developing device according to claim 7, which develops the electrostatic latent image formed on the latent image carrier.
A process cartridge comprising: A latent image carrier,
A charging device for uniformly charging the surface of the latent image carrier,
An image exposure apparatus that forms an electrostatic latent image by exposing the latent image carrier after uniform charging,
The developing device according to claim 7, which develops the electrostatic latent image formed on the latent image carrier.
A transfer device for transferring a developed image from the latent image carrier to a recording medium,
A fixing device for fixing the developed image transferred to the recording medium,
An image forming apparatus comprising:

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