JP2014174435A - Developing device, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device which is capable of preventing the change of the contact pressure of a regulation member to the surface of a developing roller by suppressing shaving caused by the sliding or the like of a fastening surface on the side of a developing container where the regulation member is fastened, even when the detachment and attachment operations of the regulation member are performed two or more times.SOLUTION: In the developing device including a developing roller 12 and a regulation member 21 which is installed in a developing container 23 made of resin and whose top end is abutted on or approaches the surface of the developing roller 12, to regulate the layer thickness of a developer carried on the surface of the developing roller 12, in a fastening part in the developing container 23 where the regulation member 21 is fastened by a fastener, a regulation member attachment surface 31 as the fastening surface exclusive for fastening is provided so as to project from the surroundings of the fastening part. The regulation member attachment surface 31 is made of metal whose hardness is higher than that of a material of which the regulation member 21 is made and is formed by a component separate from the developing container 23.

Description

  The present invention relates to a developing device used in a developing process of an image forming apparatus such as an electrophotographic copying machine or a printer, a process cartridge, and an image forming apparatus including the developing device.

  In an image forming apparatus such as an electrophotographic copying machine or printer, a visible image is formed by attaching toner (developer) to an electrostatic latent image formed on the surface of an electrostatic latent image carrier such as a photosensitive drum. A developing device is provided.

  The developing device generally includes a developing roller that abuts on or close to the surface of the electrostatic latent image carrier and causes the toner carried on the surface to adhere to the electrostatic latent image carrier by static electricity, and a toner that abuts the developer roller and contacts the toner. A toner supply roller that supplies toner conveyed from the storage side to the developing roller, and a regulating member that regulates the layer thickness so that the toner layer carried on the surface of the developing roller has a uniform thickness are provided in the developing container. is set up.

  By the way, in an image forming apparatus (such as a copying machine or a printer) provided with such a developing device, in order to obtain a high-quality image (toner image) without density unevenness, toner carried on the surface of the developing roller by a regulating member It is important to always regulate the layer to a uniform thickness. For this reason, it is necessary to accurately position the regulating member with respect to the developing roller and fix (fasten) it in the developing container.

  Therefore, for example, in the developing device described in Patent Document 1, a fastening surface (fixing member fixing member) is fixed in the developing container in a state where the leading ends on both ends in the longitudinal direction of the blade-like restricting member are in contact with the restricting member contact portion. Part) is fixed with a bolt (fastener) together with the reinforcing member.

  In the developing device as in Patent Document 1, since the developer container is generally formed of a resin material in consideration of productivity, cost, and the like, the fastening surface (the restricting member fixing portion) of the restricting member is also formed of resin. . On the other hand, the blade-like regulating member that regulates the layer thickness of the toner layer on the surface of the developing roller is generally formed of an elastic metal material so that the positioning state is stably and accurately maintained for a long time with respect to the developing roller. Has been.

  By the way, for example, at the time of repair accompanying a failure of the developing device, periodic maintenance, or recycling, an operation of once removing the regulating member whose tip side is in contact with the surface of the developing roller and then attaching it again is performed. For this reason, at the time of removing and attaching the restricting member, the metal restricting member rubs against the resin fastening surface (the restricting member fixing portion). It is shaved.

  For this reason, when the removal and attachment work of the regulating member is performed a plurality of times, the amount of scraping of the surface on the fastening surface side increases accordingly, and the surface of the fastening surface may be inclined. Accordingly, when the regulating member is fixed to the shaved fastening surface with a fastener, the posture of the regulating member is also inclined from the initial position due to the inclination of the surface of the fastening surface, so that the contact pressure on the surface of the developing roller changes.

  As described above, when the contact pressure on the surface of the developing roller changes due to the inclination of the regulating member (for example, the contact pressure decreases), the regulated amount of the toner layer on the surface of the developing roller changes (for example, the toner layer). ), Density unevenness or the like may occur and a high-quality image (toner image) may not be obtained.

  Therefore, the present invention suppresses scraping caused by sliding of the fastening surface in the developing container that fastens the regulating member even when the regulating member is removed and attached multiple times, and the developing roller surface of the regulating member It is an object of the present invention to provide a developing device, a process cartridge, and an image forming apparatus that can prevent the contact pressure on the surface from changing.

In order to achieve the above object, a developing device according to the present invention includes a developing roller that supports a developer on a surface thereof and is rotatably supported to supply the developer to an image carrier, and a longitudinal direction of the developing roller. And a regulating member that regulates the layer thickness of the developer carried on the surface of the developing roller by being installed in a resin-made developing container along with the tip part being in contact with or close to the surface of the developing roller, In the developing device, the fastening part in the developing container to which the regulating member is fastened by a fastener is provided with a fastening surface dedicated for fastening so as to protrude from the periphery of the fastening part,
It is characterized in that the hardness of at least the surface of the fastening surface with which the regulating member abuts is made higher than the hardness of the material forming the regulating member.

  The process cartridge according to the present invention includes at least an image carrier on which an electrostatic latent image is carried on a surface, and a developing device that visualizes the developer by attaching a developer to the electrostatic latent image on the surface of the image carrier. The cartridge is characterized in that the developing device is the developing device according to any one of claims 1 to 7.

  An image forming apparatus according to the present invention includes at least an image carrier on which an electrostatic latent image is carried, and a developing device that visualizes the developer by attaching a developer to the electrostatic latent image on the surface of the image carrier. In the image forming apparatus, the developing device is a developing device according to any one of claims 1 to 7.

  According to the present invention, the fastening part in the developing container to which the regulating member is fastened by the fastener is provided with a fastening surface dedicated for fastening so as to protrude from the periphery of the fastening part. At least the surface with which the regulating member abuts is made higher than the hardness of the material forming the regulating member.

  Accordingly, even when the fastening of the restricting member to the fastening surface is repeated a plurality of times, the fastening surface is not scraped, and the fastening is prevented from being shifted from the normal position. Accordingly, the contact pressure of the regulating member with respect to the developing roller can be held at the normal position, so that the layer thickness of the developer carried on the surface of the developing roller can be stably regulated to be constant. As a result, a high-quality image can be obtained.

1 is a schematic configuration diagram showing an electrophotographic printer provided with a developing device according to an embodiment of the present invention. FIG. 2 is a schematic sectional view showing a process cartridge according to the present embodiment. FIG. 2 is a schematic perspective view showing the vicinity of a developing roller in a developing container in the present embodiment. FIG. 3 is a schematic perspective view showing a state in which a developing roller in the developing container in the embodiment is removed. FIG. 3 is a schematic perspective view showing the vicinity of a regulating member mounting surface in the developing container in the present embodiment. FIG. 3 is a schematic perspective view illustrating a mounting state of a regulating member mounting surface in the developing container according to the present embodiment. FIG. 6 is a schematic perspective view showing the vicinity of a regulating member mounting surface in a developing container in a conventional structure. (A) is a figure which shows the measurement result of the contact pressure with respect to the developing roller of a control member when a control member attachment surface is a conventional structure, (b) is a control member attachment surface in this embodiment. The figure which shows the measurement result of the contact pressure with respect to a developing roller. The figure which shows the contact state to the developing roller of a control member in the control member attachment surface in the conventional structure. FIG. 10 is a schematic perspective view showing the vicinity of a regulating member mounting surface in a developing container according to a modification of the embodiment. FIG. 9 is a schematic cross-sectional view showing a state in which a regulating member (supporting portion) is attached to a seating surface in a developing container in a conventional structure.

Hereinafter, the present invention will be described based on the illustrated embodiments.
FIG. 1 is a schematic configuration diagram illustrating an electrophotographic printer as an image forming apparatus including a developing device according to an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view illustrating a process cartridge according to the present embodiment. .

(Printer configuration, image forming operation)
As shown in FIG. 1, a printer 1 according to this embodiment includes a photosensitive drum 3 as an image carrier in an apparatus main body 2, and a circumferential direction of the photosensitive drum 3 around the photosensitive drum 3. A charging roller 4, a developing device 5, a transfer roller 6, and a cleaning blade 7. Details of the developing device 5 which is a feature of the present invention will be described later. In the present embodiment, the photosensitive drum 3, the charging roller 4, the developing device 5, and the cleaning blade 7 are unitized as a process cartridge 8 (see FIG. 2), and the process cartridge 8 is an apparatus. The main body 2 is detachably mounted.

  Further, an exposure device 9 is provided in the upper part of the apparatus main body 2 for writing by irradiating the surface of the charged photosensitive drum 3 with laser light, and in the lower part, a paper P as a recording material is loaded. A paper cassette 10 is installed. Further, a fixing device 11 is installed on the downstream side of the transfer nip between the photosensitive drum 3 and the transfer roller 6 in the apparatus main body 2 in the paper transport direction.

  Next, an image forming operation by the printer 1 will be described.

  A voltage (for example, a voltage obtained by superimposing an AC voltage on a DC voltage) is applied to the charging roller 4 and rotated to uniformly charge the surface of the photosensitive drum 3 rotating in the arrow direction at a predetermined process speed. Then, an electrostatic latent image corresponding to image information input from, for example, an external personal computer is formed on the surface of the photosensitive drum 3 by exposure with laser light from the exposure device 9.

  Then, the electrostatic latent image formed on the surface of the photosensitive drum 3 is developed (visualized) by attaching toner (developer) by the developing roller 12 to which the developing bias of the developing device 5 is applied. Thereby, a toner image is formed on the surface of the photosensitive drum 3.

  At this time, the uppermost sheet P is taken out from the sheet feeding cassette 10 by the sheet feeding roller 13 and the like, and the sheet P conveyed through the conveying path is temporarily held by the registration roller pair 14. The paper P in the paper feed cassette 10 is biased toward the paper feed roller 13 by a spring member (not shown). The sheet P held by the registration roller pair 14 is transferred to the transfer nip between the photosensitive drum 3 and the transfer roller 6 to which a transfer bias is applied in accordance with the toner image formation timing on the surface of the photosensitive drum 3. The toner image is transferred onto the paper P.

  Then, the sheet P on which the toner image has been transferred is conveyed to the fixing device 11 and heated and pressed at the fixing nip between the pressure roller 11a of the fixing device 11 and the fixing roller 11b incorporating a heating member (not shown). As a result, the toner image is fixed on the paper P. The paper P having the toner image fixed on the surface thereof is conveyed by the paper discharge rollers 15a and 15b and discharged onto the paper discharge tray 16.

(Configuration of developing device 5)
As shown in FIGS. 1 and 2, the developing device 5 according to this embodiment includes the developing roller 12 that contacts the surface of the photosensitive drum 3 and rotates in the direction of the arrow, a toner supply roller 20, and the developing roller 12. A regulating member 21 that regulates the toner layer, a toner accommodating portion 22 that accommodates toner as a developer, and the like are provided in the developing container 23. The developing container 23 is integrally formed of a resin material. As the toner as the developer, in this embodiment, a toner containing oil-containing silica as an external additive is used.

  As shown in FIG. 3, the developing roller 12 is configured by providing an elastic layer (surface layer) 25 made of, for example, a rubber material around a metal core shaft 24, and a bearing portion 26 provided in the developing container 23. Is rotatably supported. In FIG. 3, the bearing portion on the right side of the developing roller 12 is omitted.

  Also, as shown in FIG. 4, both end portions in the longitudinal direction of the developing roller 12 (one end portion in the figure) are for preventing toner leakage from the longitudinal end portion of the developing roller 12 to the outside during the developing operation. An end seal member 27 is provided. The end seal member 27 is slidably in contact with the end side surface of the elastic layer (surface layer) 25 of the developing roller 12. In FIG. 4, the developing roller 12 is removed.

  The toner replenishing roller 20 rotates in contact with the developing roller 12 with a predetermined pressure uniformly along the longitudinal direction, and replenishes the toner supplied to the surface of the toner replenishing roller 20 to the surface of the developing roller 12. As shown in FIGS. 3 and 4, the toner supply roller 20 is configured by, for example, a sponge layer (elastic layer) 29 and a felt (not shown) attached to the surface of a metal core shaft 28. Further, it is rotatably supported by a bearing portion (not shown) provided in the developing container 23.

  The regulating member 21 regulates the toner layer carried on the surface of the developing roller 12 to a thin layer having a constant thickness by having the tip side abut on (or close to) the surface of the developing roller 12. As shown in FIGS. 3 and 4, both end portions in the longitudinal direction of the restricting member 21 (one end portion in the figure) are restricting member mounting surfaces 31 provided at fastening sites in the developing container 23 (see FIG. 5). It is positioned by being inserted into a positioning pin 32 formed on the lower side. The regulating member 21 is fastened and fixed to the regulating member mounting surface 31 with a screw 34 as a fastener. Details of the restricting member mounting surface 31, which is a feature of the present invention, will be described later.

  The toner storage unit 22 stores toner (not shown) therein, and agitates the toner by rotating the toner agitating member 30 and supplies the agitated toner to the toner supply roller 20 side.

  A driving mechanism (not shown) connected to a driving source is connected to the developing roller 12, the toner replenishing roller 20, and the toner stirring member 30, and these members (the developing roller 12, The toner supply roller 20 and the toner stirring member 30) are rotated.

(Configuration of restriction member 21)
As shown in FIGS. 3 and 4, the regulating member 21 has a blade-like regulating portion 21a and a support portion 21b. The restricting portion 21 a abuts on the surface of the developing roller 12 (see FIG. 3) and restricts the thickness (attachment amount) of the toner layer carried on the surface of the developing roller 12.

  The restricting portion 21a is preferably an elastic material in order to come into contact with the developing roller 12 with a predetermined contact pressure, and the restricting portion 21a may charge the toner, so that it is necessary to suppress deterioration with time. For this reason, it is desirable to use a metal material such as SUS having elasticity. The thickness of the restricting portion 21a is desirably about 0.1 to 0.3 mm. The material of the restricting portion 21a can be a rubber material.

  The support portion 21b supports the restricting portion 21a and is fastened to the restricting member mounting surface 31 (see FIG. 5) by screws 33 at both ends. Moreover, since the material of the support part 21b needs rigidity so that the control part 21a may be arrange | positioned in a predetermined position, it is desirable that it is rolled steel plates, such as SECC. The thickness of the support portion 21b is desirably about 0.8 to 2 mm.

  The integration of the restricting portion 21a and the support portion 21b is preferably screw fastening, caulking, or welding if the restricting portion 21a is a metal material, and adhesion or bonding if the restricting portion 21a is a rubber material. It is desirable that it be integrally formed with the support portion 21b.

(Structure of the regulating member mounting surface 31)
As shown in FIGS. 5 and 6, in this embodiment, the regulating member mounting surface 31 that is a fastening surface is made of metal and is formed as a separate part from the resin developing container 23. A cylindrical mounting portion 31a is integrally formed on the back side of the regulating member mounting surface 31, and this mounting portion 31a is press-fitted into a mounting hole 36 provided in a support surface 35 integrally formed in the developing container 23. Is done.

  In addition, the structure which press-fits into the opening part provided in the back side of the control member attachment surface 31 by making the attachment part 31a into a different body may be sufficient. In this case, the separate attachment portion 31a may be formed of a resin material.

  The restricting member mounting surface 31 is a shape in which four projecting surfaces projecting in the radial direction at intervals of 90 degrees along the circumferential direction are integrally formed on the outer peripheral portion of the annular surface, and have a predetermined thickness. . As described above, since the regulating member mounting surface 31 has a predetermined thickness, when the mounting portion 31a is press-fitted into the mounting hole 36 of the support surface 35 and fixed as shown in FIG. The position is higher than the support surface 35. A screw hole 33 for fastening a screw 34 (see FIGS. 3 and 4) is formed in the restricting member mounting surface 31.

  Further, an arrangement surface 37 provided with positioning pins 32 on the lower side of the regulating member mounting surface 31 is integrally formed on the support surface 35 in the developing container 23 so as to protrude. The arrangement surface 37 and the regulating member mounting surface 31 have the same height.

  As a method for assembling the regulating member mounting surface 31 (mounting portion 31a) as a separate part into the developing container 23, for example, a resin portion of the developing container 23 is molded in advance, and the metallic regulating member mounting surface 31 ( There may be mentioned a method of inserting the attachment part 31a) in a subsequent process. As a method of inserting by post-processing, there are methods such as heating and pushing, press-fitting without heating, and driving without heating. Among them, the insert that is heated and pushed in is particularly desirable because the force applied to the developing container 23 is small and the influence on the component dimensions of the developing container 23 before and after processing is small.

  Moreover, as a metal material used for the restricting member attachment surface 31 (attachment portion 31a), for example, a soft (low hardness) metal material such as an aluminum material supports the restricting member 21 when the restricting member 21 is removed or attached. There is a possibility that a problem of being scraped by sliding with the portion 21b may occur. In addition, when the material is easily oxidized (for example, iron), the surface of the material forms an oxidizing substance generally called rust while the process cartridge 8 is used up to the normal endurance number of sheets. This is not preferable because a problem that the quality of the image deteriorates due to the substance being mixed with the toner.

  For this reason, as a metal material which forms the regulation member attachment surface 31 (attachment part 31a), it is harder than the metal (for example, rolled steel plate) which forms the support part 21b of the regulation member 21, and is hard to oxidize, stainless steel, It is desirable to use either phosphor bronze or brass.

  As described above, in the present embodiment, the restriction member attachment surface 31 (attachment portion 31a) is a separate part, and the restriction member attachment surface 31 (attachment portion 31a) is formed of a metal material having high hardness. As described above, the problem when the regulating member mounting surface is formed of a resin material integrally with the developing container will be described below with reference to FIG. 7 is the same as the present embodiment shown in FIGS. 5 and 6 except that the regulating member mounting surface 31 ′ is formed of a resin material integrally with the developing container 23.

  In general, the material of the developing container 23 is a resin such as ABS, PC, PS, or a polymer alloy using a plurality of these resins. Conventionally, as shown in FIG. 31 'is also integrally formed of a resin material. In this case, when the support portion 21b of the restriction member 21 is fastened to the restriction member attachment surface 31 'in the developing container 23, the support portion 21b, which is a rolled steel plate, is harder than the restriction member attachment surface 31' of the resin material. Therefore, although it is slight, the regulating member mounting surface 31 'is deformed by scraping due to sliding.

  Further, the fastening force of the screw 33, which is a fastener for fastening the regulating member 21 to the regulating member mounting surface 31 ', requires a certain level of force to securely fasten the regulating member 21 to the regulating member mounting surface 31'. However, if a force more than necessary is applied, the amount of deformation of the restricting member mounting surface 31 ′ increases, or the shape of the screw hole 33 in the restricting member attaching surface 31 ′ is scraped against the fastening force, resulting in a so-called screw fool. A malfunction that occurs. For this reason, it is necessary to set the fastening force of the screw fastened to the screw hole 33 to a predetermined value or less.

  Further, the regulating member mounting surface 31 ′ provided on the support surface 35 in the developing container 23 and the arrangement surface 37 of the positioning pin 32 have the same height. Furthermore, the fastening position of the regulating member 21 (support portion 21b) to the regulating member mounting surface 31 ′ is disposed above the positioning position (the placement surface 37 provided with the positioning pins 32) (for these configurations, The same applies to the case of the present embodiment shown in FIGS.

  In such a configuration, during the fastening operation, the regulating member 21 (support portion 21b) first comes into contact with the end region on the side opposite to the arrangement surface 37 (upper side in FIG. 7) of the regulating member mounting surface 31 ′. It is easy to become a posture. When the fastening operation of the regulating member 21 (support portion 21b) is performed with a screw in such a posture, the fastening member is fastened to the end region on the side opposite to the arrangement surface 37 (upper side in FIG. 7) of the regulating member mounting surface 31 ′. It becomes easy to concentrate power. For this reason, the amount of deformation due to sliding or the like in the upper region portion of the restricting member mounting surface 31 ′ is likely to be larger than other portions (lower portion (arrangement surface 37 side region)).

  In addition, during the above fastening operation, the arrangement surface 37 provided with the positioning pin 32 is not directly applied with the fastening force as much as the regulating member mounting surface 31a. It becomes smaller than the mounting surface 31a.

  By the way, in the assembling process of the developing device 5, if it is a normal assembling work, the fastening work of the regulating member 21 to the regulating member mounting surface 31 'is only once. For this reason, when the regulating member mounting surface 31 ′ is formed integrally with the developing container 23 with a resin material as in the prior art, the amount of deformation due to scraping of the regulating member mounting surface 31 ′ is small, and thus the regulating member The influence of the pressure 21 (regulating portion 21a) on the contact pressure to the developing roller 12 is small.

  However, for example, in the inspection of the assembling process of the developing device 5, when some abnormality or attachment failure is recognized and repair is required, or a process in which the normal number of durable sheets is terminated due to regular maintenance or user use When the cartridge 8 is collected and recycled, the regulating member 21 and the like are once removed. Then, after performing a predetermined operation such as cleaning the removed regulating member 21, developing roller 12, toner supply roller 20, etc., the regulating member 21 is fastened to the regulating member mounting surface 31 ′ in the developing container 23 again. Since the work is performed, the greater the number of times, the greater the amount of deformation due to the cutting or the like of the regulating member mounting surface 31 '.

  At this time, as described above, the amount of deformation due to sliding or the like in the upper region portion of the restricting member mounting surface 31 ′ is likely to be larger than other portions (lower region portions).

  Therefore, in order to solve such a problem, in the embodiment of the present invention, as shown in FIGS. 5 and 6, the metal restricting member mounting surface 31 (mounting portion 31 a) having high hardness is provided as a separate part. In this structure, the mounting portion 31a is press-fitted into a mounting hole 36 provided in the support surface 35 and fixed. As a result, the restricting member mounting surface 31 to which the restricting member 21 (support portion 21b) is abutted and fastened is a small surface dedicated for fastening that is one step higher than the support surface 35, and more than the support portion 21b of the restricting member 21. Also has a high hardness. Further, by forming the screw hole 33 inside the regulating member mounting surface 31, the surface of the regulating member mounting surface 31 can be made a small area which is about the area of the screw head of the screw 33 which is a fastener. .

  Therefore, as described above, when the restriction member 21 is removed and attached a plurality of times, even if the support portion 21b of the restriction member 21 slides on the restriction member attachment surface 31, the restriction is higher in hardness than the support portion 21b. Almost no shaving due to sliding or the like occurs on the member mounting surface 31. For this reason, even when the regulating member 21 (support portion 21b) is repeatedly fastened to the regulating member mounting surface 31, the regulating member mounting surface 31 does not become an inclined surface due to scraping or the like. It is fastened well to the regulating member mounting surface 31 without being displaced from the position.

  As a result, even when the fastening to the regulating member mounting surface 31 by removing and attaching the regulating member 21 is performed a plurality of times, the contact pressure of the regulating member 21 (the regulating portion 21 a) almost changes with respect to the developing roller 12. A stable contact state is maintained without any problems.

  Further, in the present embodiment, the regulating member mounting surface 31 for fastening the regulating member 21 (support portion 21b) is installed as a metal separate part so as to protrude from the support surface 35 in the developing container 23, And the surface is a small surface dedicated for fastening.

  This is because if the area of the fastening surface for fastening the regulating member 21 (support portion 21b) is large and does not protrude from the periphery, warping or sink marks or the like may occur when the developing container 23 is molded. The surface also has an irregular shape that is not intended. For this reason, when the regulating member 21 (support portion 21b) is fastened to the fastening surface, the regulating member 21 (support portion 21b) may be displaced from the normal position. As a result, it becomes difficult to manage the contact pressure of the regulating member 21 (regulating portion 21a) against the developing roller 12, and it becomes difficult to manage the layer thickness of the toner amount carried on the surface of the developing roller 12.

  On the other hand, in this embodiment, as described above, the restriction member mounting surface 31 to which the restriction member 21 (support portion 21b) is fastened is a small surface dedicated for fastening that is one step higher than the support surface 35, and It is formed as a separate part with a metal material with high hardness. This prevents the tightened restriction member 21 (support part 21b) from being displaced from the normal position, and thus the contact pressure of the restriction member 21 (restriction part 21a) to the developing roller 12 can be easily managed. Management of the layer thickness of the toner amount carried on the surface of the developing roller 12 is also facilitated.

  FIG. 8A shows a restriction member 21 (restriction portion 21a) in the case of a conventional structure in which the restriction member mounting surface 31 ′ is formed of a resin material integrally with the developing container 23 as shown in FIG. It is a measurement result of the contact pressure with respect to the developing roller 12 of the regulating member 21 when the fastening to the regulating member mounting surface 31 ′ is performed a plurality of times.

  As is apparent from this measurement result, the contact pressure against the developing roller 12 changes (increases) as the number of fastenings of the regulating member 21 to the regulating member mounting surface 31 'increases. This is because the resin regulating member mounting surface 31 ′ is scraped by sliding with the support portion 21 b of the regulating member 21 having relatively high hardness at the time of fastening, so that the developing roller of the regulating member 21 (regulating portion 21 a). This is because the position of contact with 12 is shifted.

  Specifically, as shown in FIG. 9, the fastening of the regulating member 21 (support portion 21 b) to the regulating member mounting surface 31 ′ is repeated a plurality of times, so that the regulating member mounting surface 31 ′ of the resin material is relatively Further, it is scraped off by sliding with the support portion 21b of the restricting member 21 having high hardness. In addition, in FIG. 9, the screw which is a fastener is abbreviate | omitted.

  At this time, as described above, the amount of deformation due to sliding or the like in the upper region portion of the restricting member mounting surface 31 ′ is larger than that of other portions (region portion on the lower side (placement surface 37 side)). Therefore, the restricting member mounting surface 31 ′ becomes an inclined surface having a larger inclination toward the upper side.

  In addition, in the arrangement | positioning surface 37 in which the positioning pin 32 was provided, since fastening force is not applied directly like the control member attachment surface 31 ', the scraping by the sliding with the support part 21b of the control member 21 is small, and the upper side ( The regulating member mounting surface 31 ′ side) is slightly inclined.

  For this reason, when the regulating member 21 (support portion 21b) is fastened to the regulating member mounting surface 31 ′ with screws, the supporting portion 21b of the regulating member 21 is inclined along the inclined surface of the regulating member mounting surface 31 ′. Installed at. Therefore, the restricting portion 21a of the restricting member 21 is similarly inclined according to the inclination of the support portion 21b (in FIG. 9, the state inclined to the left side from the normal position), and the front end side is the surface of the developing roller 12. Strongly abuts so that it bites into. Note that the restricting portion 21 a ′ and the support portion 21 b ′ of the restricting member 21 indicated by a two-dot chain line indicate normal positions in the initial state where the surface of the restricting member mounting surface 31 ′ is not inclined.

  In this case, the amount of pushing into the developing roller 12 is increased by strongly contacting the surface of the developing roller 12 so that the regulating portion 21a of the regulating member 21 faces inward from the regular position, and the amount of pressing into the developing roller 12 increases. The contact pressure is larger than that at the normal position.

  As described above, when the contact pressure of the regulating member 21 (regulating portion 21a) to the developing roller 12 is higher than that in the normal case, the developing is performed even though the toner (developer) is sufficiently present in the developing container 23. A predetermined amount of toner does not adhere on the roller 12. For this reason, the toner image obtained by development has white spots and density unevenness, and the image quality deteriorates. Furthermore, the toner carried on the developing roller 12 is greatly damaged, so that the toner deterioration is accelerated. As a result, the toner adheres to the regulating member 21 (regulating portion 21a) and the toner image is soiled. Bad effects come out.

  In contrast to the structure of the present embodiment shown in FIGS. 5 and 6 and the conventional structure shown in FIG. 7, the restricting member mounting surface 31 ′ is provided below the arrangement surface 37 provided with the positioning pins 32. In contrast to this, in contrast to the state shown in FIG. 9, the restricting member mounting surface 31 ′ becomes an inclined surface having a larger inclination toward the lower side (side).

  In this case, the amount of pushing into the developing roller 12 is reduced by contacting the surface of the developing roller 12 so that the restricting portion 21a of the restricting member 21 faces outward from the normal position, so that the pressing force against the developing roller 12 is reduced. The contact pressure is smaller than that in the normal position.

  As described above, when the contact pressure of the regulating member 21 (regulating portion 21a) to the developing roller 12 becomes smaller than that at the normal position, the amount of toner adhering to the developing roller 12 becomes larger than necessary. The layer thickness of the toner carried on the toner 12 becomes larger than necessary. For this reason, the background of the toner image obtained by the development is caused and the image quality is deteriorated.

  On the other hand, in this embodiment, as described above, the restriction member mounting surface 31 to which the restriction member 21 (support portion 21b) is fastened is a small surface dedicated for fastening that is one step higher than the support surface 35, and It is formed as a separate part with a metal material with high hardness. Thereby, even when the fastening of the regulating member 21 (support portion 21b) to the regulating member mounting surface 31 is repeated a plurality of times, the regulating member mounting surface 31 is not scraped, and the regulating member 21 (supporting portion 21b) to be fastened is tightened. Displacement from the normal position is prevented. Therefore, the contact pressure of the regulating member 21 (regulating portion 21a) with respect to the developing roller 12 can be held at the normal position.

  In the present embodiment, since toner containing oil-containing silica is used as an external additive, the regulating member 21 (regulating portion 21a) contacts the developing roller 12 to regulate the thickness of the toner layer. In addition, damage to the toner can be reduced. Therefore, toner deterioration can be suppressed.

  In FIG. 8B, as in the present embodiment shown in FIG. 5, the regulating member mounting surface 31 to which the regulating member 21 (support portion 21 b) is fastened is formed as a separate part with a hard metal material. In the case of the structure, it is a measurement result of the contact pressure of the regulating member 21 against the developing roller 12 when the regulating member 21 (the regulating portion 21a) is fastened to the regulating member mounting surface 31 a plurality of times.

  As is apparent from this measurement result, even when the number of fastenings of the regulating member 21 to the regulating member mounting surface 31 increases, the contact pressure against the developing roller 12 changes only slightly. This is because, when the restricting member 21 (support portion 21b) is fastened, the metal restricting member mounting surface 31 having a high hardness is prevented from being scraped, so that the restricting member 21 (the restricting portion 21a) contacts the developing roller 12. This is because the contact position is hardly displaced from the normal position.

  As a result, the toner layer carried on the developing roller 12 during the developing operation can be stably held at a predetermined thickness, so that a high-quality toner image can be transferred and fixed on the paper for output.

By the way, in above-described embodiment, the regulating member mounting surface 31 to which the regulating member 21 (support portion 21b) is fastened has a structure formed as a separate part with a metal material having high hardness. In addition to this, for example, as in the modification shown in FIG. 10, only the surface portion of the regulating member mounting surface 31 ^″ integrally molded with the support surface 35 in the developing container 23 is formed with a high hardness surface layer 40. You may make it cover. Other configurations are the same as those of the above embodiment.

In this case, for example, the surface layer 40 is formed by coating the surface portion of the regulating member mounting surface 31 ^″ with a metal having high hardness in a subsequent process. Examples of the method of coating the metal on the surface portion of the restricting member mounting surface 31 ^'' include plating and vapor deposition. Further, the material of the metal to be coated is preferably gold, silver, chrome or the like which has high hardness and is easy to coat.

In this way, also in the configuration in which the surface portion of the regulating member mounting surface 31 ^″ is covered with the surface layer 40 made of a metal having high hardness, the fastening of the regulating member 21 (support portion 21b) to the regulating member mounting surface 31 is the same as described above. Even when the above is repeated a plurality of times, the surface layer 40 of the regulating member mounting surface 31 ^″ is not scraped, and the fastening regulating member 21 (support portion 21b) is prevented from being displaced from the normal position. Therefore, the contact pressure of the regulating member 21 (regulating portion 21a) with respect to the developing roller 12 can be held at the normal position.

In FIG 10, the regulating member mounting surface 31 ^'' but by coating a high hardness metal to form a surface layer 40 on the surface of, regulating the excellent ceramic wear resistance in addition to the metal member mounting surface 31 ^{' The} surface layer 40 may be coated to form a surface layer 40 having a high hardness.

  By the way, as a conventional structure for positioning and fixing a regulating member that regulates the toner layer carried on the surface of the developing roller to a predetermined thickness at an attaching portion in the developing container, for example, a structure as shown in FIG. 11 is conceivable.

  In the conventional structure shown in FIG. 11, a metal shaft 102 is fitted into a hole 101a provided in the developing device frame 101 of the developing container 100 made of a resin material so that the tip side protrudes from the seating surface 101b. Then, a hole 103 b provided in the support portion 103 a of the restricting member 103 is press-fitted into the metal shaft 102, brought into contact with the support portion 103 a on the seat surface 101 b, and the restricting member 103 by the push nut 104 fitted to the metal shaft 102. The support portion 103a is fastened so as to be in pressure contact with the seat surface 101b.

  The regulating member 103 (supporting portion 103a) is provided with a regulating portion 103c for contacting the surface of the developing roller 105 and regulating the toner layer to a predetermined thickness. Further, the seat surfaces 101b from which the metal shafts 102 protrude are provided on both ends in the longitudinal direction of the developing roller 105, respectively.

  By the way, also in such a conventional structure, the attachment / detachment to the seat surface 101b of the control member 103 (support part 103a) may be repeated several times like the above-mentioned embodiment. In this case, when the hole 103b of the restricting member 103 (supporting portion 103a) is press-fitted into the metal shaft 102 and the restricting member 103 is brought into contact with the protruding seat surface 101b, there is a slight gap between the metal shaft 102 and the hole 103b. If there is a backlash or the like, the regulating member 103 is pressed against the seat surface 101b with the push nut 104 while keeping the posture inclined obliquely by this backlash.

  For this reason, the supporting portion 103a of the regulating member 103 is brought into pressure contact with one end side in the vertical direction of the seat surface 101b by the pressure contact force of the push nut 104, and thereby, one of the seat surfaces 101b is pressed. There is a possibility that a problem that the end portion is slid and scraped may occur.

  Thus, as shown in FIG. 11, the conventional structure in which the metal shaft 102 for press-fitting the support portion 103a is provided in the hole 103b provided in the center of the seating surface 101b, as in the above-described embodiment. This is different from the configuration of the present invention in which the hardness of the entire surface of the regulating member mounting surface 31 (corresponding to the seating surface 101b) is increased. Therefore, in such a conventional structure, the effect as in the above-described embodiment cannot be obtained.

1 Printer (image forming device)
DESCRIPTION OF SYMBOLS 2 Apparatus main body 3 Photosensitive drum 5 Developing apparatus 8 Process cartridge 12 Developing roller 20 Toner replenishment roller 21 Restriction member 21a Restriction part 21b Support part 23 Developing container 31, 31 ^'' Restriction member attachment surface (fastening surface)
34 Screw (fastener)
40 Surface layer

JP 2007-298746 A

Claims (9)

A developer roller supported on the surface and rotatably supported to supply the developer to the image carrier, and installed in a resin developer container along the longitudinal direction of the developer roller. In a developing device having a regulating member that regulates the layer thickness of the developer carried on the surface of the developing roller, with a leading end abutting on or close to the surface of the roller,
The fastening part in the developing container where the regulating member is fastened by a fastener is provided with a fastening surface dedicated for fastening so as to protrude from the periphery of the fastening part,
A developing device characterized in that the hardness of at least the surface of the fastening surface with which the restricting member abuts is higher than the hardness of the material forming the restricting member.   The developing device according to claim 1, wherein the fastening surface is made of a metal having a hardness higher than that of the material forming the regulating member, and is formed as a separate part from the developing container.   The developing device according to claim 2, wherein the metal fastening surface is attached to the fastening portion in the resin-molded developer container by post-processing.   The fastening surface is integrally formed with the fastening part in the resin-made developing container, and only the surface of the fastening surface with which the regulating member abuts is higher than the hardness of the material forming the regulating member. 2. The developing device according to claim 1, wherein the developing device is processed as described above.   5. The developing device according to claim 4, wherein only a surface portion of the fastening surface with which the restriction member contacts is covered with a metal having a hardness higher than that of a material forming the restriction member.   5. The developing device according to claim 4, wherein only a surface portion of the fastening surface with which the regulating member abuts is covered with ceramics.   The developing device according to claim 1, wherein the developer is a toner containing oil-containing silica as an external additive. In a process cartridge comprising at least an image carrier on which an electrostatic latent image is carried, and a developing device for visualizing the developer by attaching a developer to the electrostatic latent image on the surface of the image carrier,
The process cartridge according to claim 1, wherein the developing device is a developing device according to claim 1. In an image forming apparatus comprising at least an image carrier on which an electrostatic latent image is carried, and a developing device for visualizing the developer by attaching a developer to the electrostatic latent image on the surface of the image carrier,
The image forming apparatus according to claim 1, wherein the developing device is the developing device according to claim 1.