JP2023174630A - Holding device, process cartridge, and image forming apparatus - Google Patents

Abstract

To accurately set an opposite distance between a first rotating body and a second rotating body even if a positioning member is installed to be inclined relative to a housing of a holding member.SOLUTION: A holding device is provided with: a cartridge case 50 that rotatably supports a photoreceptor drum 11 (first rotating body); face plates 40 that are installed on the cartridge case 50, and are abutted with a shank 13a10 of a developing roller 13a (second rotating body) to determine an opposite distance H between the photoconductor drum 11 and the developing roller 13a; and pressing members 41 that are removably installed on the cartridge case 50 to press the shank 13a10 abutted on the face plates 40 toward the face plates 40. The face plate 40 is formed such that an abutment part 40a on which the shank 13a10 of the developing roller 13 abuts is in point contact with the shank 13a10 when seen on a cross section including a rotation center axis X1 of the photoreceptor drum 11 and a rotation center axis X2 of the developing roller 13a.SELECTED DRAWING: Figure 7

Description

The present invention relates to a holding device that rotatably holds two rotating bodies, a process cartridge that is removably installed in an image forming apparatus main body, and a copying machine, a printer, a facsimile machine, or a multifunction device thereof, etc. The present invention relates to an image forming apparatus.

Conventionally, in process cartridges installed in image forming devices such as copying machines and printers, the gap (opposing distance) between the developing roller (developer carrier) and the photosensitive drum (image carrier) has been set with high precision. In addition, for the purpose of improving maintainability, a technique is known in which a face plate (positioning member) is provided to determine the distance between the shaft of the developing roller and the shaft of the photoreceptor drum (see, for example, Patent Document 1). ).

Specifically, in the process cartridge disclosed in Patent Document 1, etc., the developing roller is moved by a limiting member (pressing member) with the shaft of the developing roller abutting against a face plate that is removably installed in the housing of the process cartridge. The shaft of the roller is pressed against the face plate.

A conventional process cartridge (holding device) has a shaft portion of the developing roller when viewed in a cross section including the central axis of rotation of the photoconductor drum (first rotating body) and the central axis of rotation of the developing roller (second rotating body). The abutting portion was formed in a planar shape so that the abutting portion of the face plate (positioning member) that the abutment abuts is in line contact (surface contact) with the shaft portion of the developing roller. Therefore, in the above-mentioned cross section, if the face plate is installed so as to be inclined relative to the housing of the process cartridge, the corner of the face plate (abutment part) may abut against the shaft of the developing roller. Sometimes I put it away. As a result, there is a possibility that the gap (opposing distance) between the photosensitive drum and the developing roller cannot be set with high precision.

This invention was made to solve the above-mentioned problems, and even if the positioning member is installed so as to be inclined relative to the housing of the holding device, the first rotating body and the first rotating body It is an object of the present invention to provide a holding device, a process cartridge, and an image forming apparatus that can set the facing distance with two rotating bodies with high accuracy.

The holding device in this invention is a holding device that rotatably holds a first rotating body and a second rotating body, and includes a housing that rotatably supports the first rotating body, and a housing that is installed in the housing. a positioning member that determines a facing distance between the first rotor and the second rotor by which the shaft portion of the second rotor abuts; a pressing member that presses the shaft part in a state of abutting against the positioning member toward the positioning member, and the positioning member has a rotation center axis of the first rotating body and a rotation center axis of the second rotating body. When viewed in a cross section including , the abutting portion against which the shaft portion of the second rotating body abuts is formed so as to make point contact with the shaft portion.

According to the present invention, even if the positioning member is installed so as to be inclined relative to the housing of the holding device, the facing distance between the first rotating body and the second rotating body can be set with high precision. A holding device, a process cartridge, and an image forming apparatus can be provided.

1 is an overall configuration diagram showing an image forming apparatus in an embodiment of the present invention. FIG. 3 is a configuration diagram showing an image forming section. FIG. 3 is a cross-sectional view showing main parts of the process cartridge in the longitudinal direction. FIG. 3 is a diagram showing a state in which a developing device is attached to a process cartridge. FIG. 3 is a diagram showing a state in which the developing device is removed from the process cartridge. FIG. 3 is a perspective view showing the main parts of the process cartridge. FIG. 3 is a cross-sectional view showing the vicinity of a face plate in the process cartridge. (A) An enlarged view showing a state in which the face plate is installed in a normal attitude, and (B) an enlarged view showing a state in which the face plate is installed in an inclined attitude. As a comparative example, (A) is an enlarged view showing a state in which the face plate is installed in a normal posture, and (B) is an enlarged view showing a state in which the face plate is installed in an inclined posture. FIG. 7 is a sectional view showing a face plate as Modification 1. FIG. They are (A) an enlarged view showing a state in which the face plate is installed in a normal posture, and (B) an enlarged view showing a state in which the face plate is installed in an inclined posture, as modification example 2. FIG. 7 is a diagram illustrating main parts of a process cartridge as a third modification.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals, and repeated explanations thereof will be simplified or omitted as appropriate.

First, referring to FIG. 1, the overall configuration and operation of the image forming apparatus 1 will be described.
In FIG. 1, 1 is a color copying machine as an image forming device, 3 is a document conveyance unit that conveys a document to a document reading unit 4, 4 is a document reading unit that reads image information of the document, and 6 is a color copying machine based on input image information. A writing section (exposure section) that emits laser light is shown.
Further, 7 is a paper feeding device in which sheets P such as paper are stored; 10Y, 10M, 10C, and 10BK are process cartridges (holding devices) as image forming units corresponding to each color (yellow, magenta, cyan, black); Reference numeral 17 indicates an intermediate transfer belt to which toner images of a plurality of colors are transferred in a superimposed manner, and reference numeral 18 indicates a secondary transfer roller which transfers the toner images formed on the intermediate transfer belt 17 onto the sheet P.
Further, 20 is a fixing device that fixes the unfixed image on the sheet P, 28 is a toner container for replenishing toner of each color to the developing device of each process cartridge 10Y, 10M, 10C, and 10BK, and 30 is a waste toner that is collected. A waste toner collection container is shown.

Here, each of the process cartridges 10Y, 10M, 10C, and 10BK (holding device) is one in which a photosensitive drum 11 as an image carrier, a charging device 12, a developing device 13, and a cleaning device 15 are integrated. (See Figure 2). Each of the process cartridges 10Y, 10M, 10C, and 10BK is replaced with a new one when it reaches the end of its life.
Toner images of respective colors (yellow, magenta, cyan, and black) are formed on the photosensitive drums 11 (image carriers) in each of the process cartridges 10Y, 10M, 10C, and 10BK.

The operation of the image forming apparatus during normal color image formation will be described below.
First, the document is conveyed from the document table by the conveyance rollers of the document conveyance section 3 and placed on the contact glass of the document reading section 4 . Then, the image information of the document placed on the contact glass is optically read by the document reading section 4.
Then, the image information of each color of yellow, magenta, cyan, and black is transmitted to the writing section 6. Laser light (exposure light) based on the image information of each color is emitted from the writing section 6 onto the photoreceptor drums 11 of the corresponding process cartridges 10Y, 10M, 10C, and 10BK, respectively.

On the other hand, the four photosensitive drums 11 are rotating clockwise in FIGS. 1 and 2, respectively. Referring to FIG. 2, first, the surface of the photosensitive drum 11 is uniformly charged at a position facing the charging device 12 (charging roller) (this is a charging process). In this way, a charged potential is formed on the photoreceptor drum 11. Thereafter, the charged surface of the photosensitive drum 11 reaches the irradiation position of each laser beam.
In the writing section 6, laser beams L corresponding to image signals are emitted from a light source in correspondence to each color. The laser beam L is incident on the polygon mirror, reflected, and then transmitted through a plurality of lenses. After passing through the plurality of lenses, the laser light passes through different optical paths for each color component of yellow, magenta, cyan, and black (this is an exposure process).

Laser light corresponding to the yellow component is irradiated onto the surface of the photosensitive drum 11 of the first process cartridge 10Y from the left side of the paper. In this way, an electrostatic latent image corresponding to the yellow component is formed on the photosensitive drum 11 after being charged by the charging roller 12a.
Similarly, the cyan component laser light is irradiated onto the surface of the photosensitive drum 11 of the second process cartridge 10C from the left in the paper, and an electrostatic latent image of the cyan component is formed. The laser beam corresponding to the magenta component is irradiated onto the surface of the photoreceptor drum 11 of the third process cartridge 10M from the left in the paper, and an electrostatic latent image corresponding to the magenta component is formed. The black component laser light is irradiated onto the surface of the photosensitive drum 11 of the fourth process cartridge 10BK from the left in the paper, and an electrostatic latent image of the black component is formed.

Thereafter, the surface of the photosensitive drum 11 on which the electrostatic latent image of each color is formed reaches a position facing the developing device 13 (see FIG. 2). Then, toner of each color is supplied onto the photoreceptor drum 11 from each developing device 13, and the latent image on the photoreceptor drum 11 is developed (this is a developing process).
Thereafter, the surfaces of the photoreceptor drums 11 after the development process reach positions facing the intermediate transfer belt 17 (intermediate transfer body) serving as an image carrier. Here, a primary transfer roller 14 is installed at each opposing position so as to come into contact with the inner circumferential surface of the intermediate transfer belt 17. Then, at the position of the primary transfer roller 14, the toner images of each color formed on the photoreceptor drum 11 are sequentially transferred onto the intermediate transfer belt 17 in an overlapping manner (this is a primary transfer step).

After the primary transfer process, the surfaces of the photosensitive drums 11 each reach a position facing the cleaning device 15 (see FIG. 2). Then, the cleaning device 15 collects the untransferred toner remaining on the photoreceptor drum 11 (this is a cleaning process). The untransferred toner collected in the cleaning device 15 is transported through the transport pipe 16 by the transport screw 15b (see FIG. 2), and is collected as waste toner in the waste toner collection container 30.
Thereafter, the surface of the photoreceptor drum 11 passes through the position of the static eliminator, and a series of image forming processes on the photoreceptor drum 11 are completed.

On the other hand, the surface of the intermediate transfer belt 17, onto which the images of each color are superimposed and transferred on the photosensitive drum 11, travels in the direction of the arrow in FIG. 1 and reaches the position of the secondary transfer roller 18. Then, at the position of the secondary transfer roller 18, the full-color image on the intermediate transfer belt 17 is secondarily transferred onto the sheet P (this is a secondary transfer step).
After that, the surface of the intermediate transfer belt 17 reaches the position of the intermediate transfer belt cleaning device 9 (cleaning device). Then, the untransferred toner on the intermediate transfer belt 17 is collected by the intermediate transfer belt cleaning device 9, and a series of transfer processes on the intermediate transfer belt 17 is completed. Note that the untransferred toner collected in the intermediate transfer belt cleaning device 9 is transported through the transport tube 16 by the transport screw 15b (see FIG. 2), and is collected as waste toner in the waste toner collection container 30.

Here, the sheet P at the position of the secondary transfer roller 18 is conveyed from the paper feeder 7 via a conveyance guide, registration rollers 19, and the like.
Specifically, the sheet P is fed by the paper feed roller 8 from the paper feed device 7 that stores the sheet P. After passing through a conveyance guide, the sheet P is guided to the registration rollers 19 . The sheet P that has reached the registration rollers 19 is conveyed toward the secondary transfer roller 18 in synchronization with the toner image on the intermediate transfer belt 17 .

Thereafter, the sheet P on which the full-color image has been transferred is guided to the fixing device 20. In the fixing device 20, the color image is fixed onto the sheet P at the nip between the fixing roller and the pressure roller.
After the fixing process, the sheet P is discharged as an output image outside the apparatus main body 1 by the paper discharge roller 29, and then stacked on the paper discharge section 5, completing a series of image forming processes.

Next, the image forming section of the image forming apparatus will be described in detail with reference to FIGS. 2 and 3.
FIG. 2 is a configuration diagram showing the process cartridge 10BK for black color. The other three process cartridges 10Y, 10M, and 10C have almost the same configuration as the black process cartridge 10BK, except for the difference in the color of toner used in the image forming process, so they are illustrated and explained below. and is omitted.

As shown in FIG. 2, the process cartridge 10BK as a holding device mainly includes a photosensitive drum 11 as an image carrier, a developing device 13, a charging device 12, a cleaning device 15, and a cartridge case 50 ( It is housed integrally in the housing.
The cleaning device 15 is provided with a cleaning blade 15a that contacts the photoreceptor drum 11 and a conveyance screw 15b.

The developing device 13 mainly includes a developing roller 13a serving as a developer carrier that faces the photosensitive drum 11 and forms a developing area, a first conveying screw 13b1 (first conveying member) facing the developing roller 13a, and a partition member. A second conveyance screw 13b2 (second conveyance member) faces the first conveyance screw 13b1 via a doctor blade 13c (second conveyance member) that opposes the developing roller 13a and regulates the amount of developer carried on the developing roller 13a. (developer regulating member), etc.

The developing device 13 accommodates a developer (two-component developer) consisting of toner and carrier.
The developing roller 13a is configured to face the photosensitive drum 11 with a small gap H (see FIG. 3) therebetween to form a developing area. As shown in FIG. 3, the developing roller 13a is composed of a magnet 13a1 that is fixed inside and forms a plurality of poles (magnetic poles) on the outer peripheral surface of the roller, and a sleeve 13a2 that rotates around the magnet 13a1. Ru.

The conveying screws 13b1 and 13b2 as conveying members convey the developer contained inside the developing device 13 in the longitudinal direction to form a circulation path (the circulation path is indicated by a broken line arrow in FIG. 3). That is, a developer circulation path is formed by a first transport path B1 by the first transport screw 13b1 and a second transport path B2 by the second transport screw 13b2.
The first conveyance path B1 and the second conveyance path B2 are separated by a partition member 13e (wall portion), and both longitudinal ends of the two conveyance paths B1 and B2 communicate with each other via communication ports 13f and 13g. ing. Specifically, with reference to FIG. 3, the upstream end in the transport direction of the first transport path B1 and the downstream end in the transport direction of the second transport path B2 are connected through the first communication port 13f. It's communicating. Further, the end of the first transport path B1 on the downstream side in the transport direction and the end of the second transport path B2 on the upstream side in the transport direction communicate with each other via the second communication port 13g. That is, the partition member 13e is disposed at positions other than both ends in the longitudinal direction.
The first conveyance screw 13b1 (first conveyance path B1) is arranged to face the developing roller 13a, and the second conveyance screw 13b2 (second conveyance path B2) is connected to the first conveyance screw 13b1 ( It is arranged so as to face the first conveyance path B1). The first conveyance screw 13b1 supplies the developer toward the developing roller 13a while conveying the developer in the longitudinal direction, and collects the developer separated from the developing roller 13a after the development process. The second conveyance screw 13b2 stirs and mixes the developer after the development process conveyed from the first conveyance path B1 and the fresh developer replenished from the toner replenishment port 13d while conveying it in the longitudinal direction.
In this embodiment, two conveyance screws 13b1 and 13b2 (conveyance members) are arranged in parallel in the horizontal direction. The two conveyance screws 13b1 and 13b2 each have a screw portion wound around a shaft portion.

The image forming process described above will be explained in more detail, focusing on the developing process.
The developing roller 13a is rotating in the direction of the arrow in FIG. As shown in FIG. 3, the developer in the developing device 13 is transferred to the toner container by rotation of the first conveyance screw 13b1 and the second conveyance screw 13b2, which are arranged with the partition member 13e interposed therebetween, in the direction of the arrow. The toner is stirred and mixed together with the toner supplied from the toner supply port 13d (inflow port) via the toner supply path 27 from the toner supply path 27, and circulates in the longitudinal direction (circulation in the direction of the broken line arrow in FIG. 3).
Note that the toner replenishment port 13d of the developing device 13 is communicated with and disconnected from the toner replenishing path 27 of the image forming apparatus main body 1 in conjunction with the attachment/detachment operation of the developing device 13 (process cartridge 10BK) to the image forming apparatus main body 1. That will happen.

The toner that has been triboelectrically charged and adsorbed onto the carrier is then pumped up onto the developing roller 13a together with the carrier by the agent lifting pole formed on the developing roller 13a. The developer carried on the developing roller 13a is conveyed in the direction of the arrow in FIG. 2 and reaches a position facing the doctor blade 13c. After the developer on the developing roller 13a is adjusted to an appropriate amount at this position, it is conveyed to a position facing the photoreceptor drum 11 (which is a developing area). Then, the toner is attracted to the latent image formed on the photoreceptor drum 11 by the electric field formed in the development area. Thereafter, as the sleeve rotates, the developer remaining on the developing roller 13a reaches above the first conveyance path B1, and is separated from the developing roller 13a at this position. Here, the electric field in the development area is defined by a predetermined voltage (development bias) applied to the development roller 13a by a power source for development, and a surface potential (developed on the surface of the photoreceptor drum 11 by the charging process and the exposure process). latent image potential).

The toner in the toner container 70 is appropriately replenished into the developing device 13 from the toner replenishing port 13d as the toner in the developing device 13 is consumed. Consumption of the toner in the developing device 13 is detected by a toner concentration sensor that magnetically detects the toner concentration (ratio of toner in the developer) of the developer in the developing device 13.
The toner supply port 13d is provided at one end of the second conveyance screw 13b2 in the longitudinal direction (the left-right direction in FIG. 3) and above the second conveyance screw 13b2 (second conveyance path B2). ing.

The characteristic configuration and operation of the process cartridge 10BK as a holding device in this embodiment will be described in detail below using FIGS. 3 to 8 and the like.
As previously explained using FIGS. 2, 3, etc., the process cartridge 10BK is a unit that is removably installed in the image forming apparatus main body 1. The process cartridge 10BK includes a photoconductor drum 11 (first rotation body) as a rotatable image carrier, and a developing roller 13a (second rotation body) as a rotatable developer carrier facing the photoconductor drum 11. body) etc. are installed. That is, the process cartridge 10BK functions as a holding device that rotatably holds the photosensitive drum 11 as a first rotating body and the developing roller 13a as a second rotating body.

Note that the photosensitive drum 11 as a first rotating body is rotatably supported by a cartridge case 50 as a housing. Specifically, the cartridge case 50 (housing) is capable of rotating the photoreceptor drum 11 via a face plate 40 (a bearing 45 that rotatably holds the photoreceptor drum 11 is installed) as a positioning member, which will be described later. I support it. More specifically, a hole (into which a bearing 45 is press-fitted) is formed in the face plate 40 held by the cartridge case 50, and the drum shaft 11a of the photoreceptor drum 11 is rotatable in the bearing 45. It has been inserted.
On the other hand, the developing roller 13a (developer carrier) serving as a second rotating body is rotatably held by the developing device 13. Further, the developing device 13 is configured to be able to accommodate a developer therein, and is installed in a detachable manner with respect to the process cartridge 10BK.

Here, with reference to FIGS. 3, 4, etc., in the process cartridge 10BK according to the present embodiment, the photoreceptor hits the shaft portion 13a10 of the developing roller 13a (which is the shaft portion of the non-rotating magnet 13a1). A face plate 40, which serves as a positioning member that determines the facing distance H (development gap) between the drum 11 and the developing roller 13a, is provided at both ends in the axial direction (the left-right direction in FIG. 3, and the direction perpendicular to the paper surface in FIG. 4). , are installed in a removable manner with respect to the cartridge case 50 (casing).
These two face plates 40 have substantially the same configuration except that they are formed symmetrically with respect to each other. The relationship between the two face plates 40 installed at both ends in the axial direction is the same for the pressing member 41 and the two wall portions 50a and 50b (regulating portions), which will be described later.

As shown in FIGS. 4 to 8, the face plate 40 (positioning member) is formed such that an abutting portion 40a against which the shaft portion 13a10 abuts protrudes toward the shaft portion 13a10 side (the left side in FIG. 4). There is.
In this embodiment, the face plate 40 is removably installed in the cartridge case 50 (casing) by fastening with a plurality of screws 60. The hole diameter of the screw hole hole in the face plate 40 is set larger than the screw diameter of the screw 60. Thereby, the relative position of the face plate 40 with respect to the cartridge case 50 can be adjusted, and the development gap H can be finely adjusted.

In the present embodiment, the two face plates 40 installed at both ends in the axial direction are configured such that the shaft portion of the non-rotating magnet 13a1 abuts against each of the two face plates 40.
On the other hand, it is also possible to configure the developing roller 13a so that the non-rotating shaft portion 13a10 and the rotatable shaft portion 13a20 are each held by two face plates 40. In such a case, one of the two face plates 40 is arranged so that the non-rotating shaft part 13a10 of the developing roller 13a (this is the shaft part for determining the orientation of the magnet 13a1 in the rotational direction) comes into contact with it. The other face plate 40 is configured such that a rotatable shaft portion 13a20 (a shaft portion for rotating the sleeve 13a2) of the developing roller 13a abuts against the other face plate 40.

Here, as shown in FIGS. 4 to 7, in the process cartridge 10BK (holding device) in this embodiment, a pressing member 41 is removably installed in a cartridge case 50 (casing).
This pressing member 41 is a member for pressing the shaft portion 13a10 in a state of abutting against the face plate 40 (positioning member) toward the face plate 40. In other words, the pressing member 41 restricts the movement of the shaft portion 13a10 in a predetermined direction away from the face plate 40 (movement to the left in FIG. 4 and downward in FIG. 7) with respect to the shaft portion 13a10 in a state of abutting against the face plate 40. It is a member for
That is, the shaft portion 13a10 is urged by the pressing member 41 in the direction of the white arrow in FIG. The distance between the axes and the photosensitive drum 11 is determined.

Here, as shown in FIG. 4, the pressing member 41 in this embodiment is formed with a substantially hemispherical contact portion 41a so as to protrude toward the shaft portion 13a10. Thereby, even if the shaft portion 13a10 that contacts the contact portion 41a rotates, the sliding resistance of the pressing member 41 can be reduced by point contact by the contact portion 41a.

As shown in FIGS. 4 to 6, the cartridge case 50 as a casing has a predetermined direction that intersects with the shaft portion 13a10 in a predetermined direction limited by the face plate 40 (positioning member) and the pressing member 41. Two wall portions 50a and 50b are provided as restricting portions that restrict movement in directions (directions that intersect with the horizontal direction).
The two wall portions 50a and 50b (regulating portions) are opposed to each other with the shaft portion 13a10 in between, and are formed in the shape of a beak (notch shape) at the tip of the cartridge case 50. The opposing distance between the two wall portions 50a and 50b is set to match (or be slightly larger than) the shaft diameter of the shaft portion 13a10.
Therefore, the shaft portion 13a10 is positioned by the pressing member 41, the face plate 40, and the two wall portions 50a, 50b, with vertical and horizontal movement being restricted. Further, as shown in FIG. 5, when the pressing member 41 is removed, the two shaft portions 13a10 can slide along the wall portions 50a and 50b.

More specifically, the two wall portions 50a and 50b (regulating portions) each move in a direction away from the photosensitive drum 11 (first rotating body) with respect to the cartridge case 50 (housing) (on the left side of FIG. 5). ) is formed to protrude.
Further, the two wall portions 50a and 50b have their root portions (the portions connected to the main body of the cartridge case 50, which are the bottom portions of the notches) located closer to the abutment portion 40a where the face plate 40 abuts against the shaft portion 13a10. is also located close to the photosensitive drum 11 (first rotating body). That is, the root portions of the two wall portions 50a and 50b are located to the right in FIG. 5 rather than the abutting portion 40a.
With such a configuration, the shaft portion 13a10 does not butt against the root portions of the two wall portions 50a, 50b, but the butt portion 40a of the face plate 40. Therefore, the facing distance H (developing gap) between the developing roller 13a and the photosensitive drum 11 can be set with high precision by the face plate 40.

Further, with reference to FIGS. 4 to 6, in the present embodiment, pressing member 41 has one end (the upper part) held by one wall 50a of two walls 50a and 50b. , the other end (lower part) fits into the recess 50b1 formed in the other wall 50b and moves away from the photosensitive drum 11 (first rotating body) (left in FIG. 4). movement is regulated.
Specifically, the pressing member 41 has a screw hole formed in its upper part. Further, a female screw portion is formed in the upper wall portion 50a at a position facing the screw hole portion of the pressing member 41. Further, a recess 50b1 (the opening width in the left-right direction in FIG. 5 is set larger than the thickness of the pressing member 41) is formed in the lower wall portion 50b so as to open upward.
Then, with the lower part of the pressing member 41 fitted into the recess 50b1, the screw 61 is screwed into the female threaded portion of the upper wall portion 50a through the screw hole portion of the pressing member 41. As a result, the pressing member 41 is fixed (positioned) to the cartridge case 50, and the function of the pressing member 41 to restrict movement of the shaft portion 13a10 in the separating direction is efficiently achieved. Note that when the pressing member 41 is to be removed from the cartridge case 50, the operation can be easily performed by unscrewing one screw 61.
In this embodiment, the pressing member 41 is removably installed on the face plate 40 by fastening screws, but the method of installing the pressing member 41 is not limited to this. For example, the pressing member 41 can be attached to the face plate 40 by snap-fitting. It can also be installed removably.

In the process cartridge 10BK (holding device) configured in this way, the position of the developing roller 13a (shaft portion 13a10) with respect to the photosensitive drum 11 (drum shaft 11a) is determined by the face plate 40. In particular, the developing roller 13a is held by the pressing member 41 so that the shaft portion 13a10 is in close contact with the face plate 40 (abutting portion 40a). Further, since the developing roller 13a is regulated so that the shaft portion 13a10 (13a20) is sandwiched between the two wall portions 50a and 50b, the attitude (inclination, angle) with respect to the photoreceptor drum 11 can be set with high accuracy. become. As a result, the distance between the axes and the positional relationship between the photoreceptor drum 11 and the developing roller 13a are determined, and the developing gap H (see FIG. 3) is accurately set to a target value.
In particular, even when the developing roller 13a receives pressure (reaction force) from the developer when the developer carried on the developing roller 13a comes into contact with the photoreceptor drum 11, the developing gap H does not change. A developing process will be performed.

In this embodiment, the two walls 50a, 50b are opened on the left side in FIG. 5 so that the shaft 13a10 can be inserted into and removed from the two walls 50a, 50b (cartridge case 50) are doing.
Thereby, the shaft portion 13a10 can be moved in the direction of the arrow in FIG. Further, the shaft portion 13a10 can be moved (slided) along the two wall portions 50a and 50b.

In this way, the process cartridge 10BK in this embodiment reduces the time and effort involved in maintaining and replacing the developing roller 13a.
Specifically, when performing maintenance or replacement of the developing roller 13a (developing device 13), the photoconductor drum 11 and the face plate 40 can be replaced without taking the time and effort of removing the photoconductor drum 11 and the face plate 40 from the process cartridge 10BK (cartridge case 50). The developing roller 13a (developing device 13) can be attached to and detached from the process cartridge 10BK (cartridge case 50) to which the developing roller 11 and the face plate 40 are attached.

In particular, with reference to FIGS. 4 and 5, in the present embodiment, two wall portions 50a and 50b (regulating portions) each have a cross section perpendicular to the center of rotation of photoreceptor drum 11 (first rotating body). When viewed from above, it is formed to be parallel to an imaginary line S1 passing through the rotation center of the photoreceptor drum 11 and the rotation center of the developing roller 13a.
This improves the ease of attaching and detaching the developing roller 13a (developing device 13) to the process cartridge 10BK. On the other hand, when the developing roller 13a receives pressure from the photosensitive drum 11 side, the shaft portion 13a10 tends to move along the walls 50a and 50b, but the pressing member 41 prevents such movement of the shaft portion 13a10 efficiently. is limited to.

Here, with reference to FIGS. 3 and 4, in the present embodiment, the face plate 40 as a positioning member is removably coupled to the cartridge case 50 (in this embodiment, by screw fastening). There is.
The cartridge case 50 is a housing for the process cartridge 10BK that is different from the developing case 13r, and holds the photosensitive drum 11, the charging device 12, and the cleaning device 15. The developing case 13r holds the developing roller 13a, two transport screws 13b1 and 13b2, and a doctor blade 13c.
Specifically, the face plate 40 has three screw holes into which the screws 60 can be inserted. Furthermore, three female screw portions are formed on the side surface of the cartridge case 50. Then, the screws 60 are screwed into the three female screw portions of the cartridge case 50 through the screw holes of the face plate 40, respectively.

Here, in a state in which the pressing member 41 is disengaged from the cartridge case 50 (one screw 61 is removed), the developing device 13 connects the shaft portion 13a10 of the developing roller 13a between the two wall portions. It is formed so that it can be moved between 50a and 50b and detached from the cartridge case 50 (process cartridge 10BK) together with the developing roller 13a.

Specifically, as shown in FIG. 4, when removing the developing device 13 from the process cartridge 10BK to which the developing device 13 is coupled via the pressing member 41 in order to perform maintenance or replacement of the developing device 13, First, the process cartridge 10BK is taken out from the image forming apparatus main body 1.
Then, as shown in FIG. 5, in the removed process cartridge 10BK, the screws 61 (one installed on each of the two face plates 40 at both ends) that connect the pressing member 41 are removed. At this time, the photosensitive drum 11 and the face plate 40 remain coupled to the cartridge case 50.
Then, as shown in FIG. 5, with the pressing member 41 removed, the developing device 13 is moved horizontally along the walls 50a and 50b of the cartridge case 50, and the developing device 13 is moved from the process cartridge 10BK. Remove. At this time, in the process cartridge 10BK, the components other than the developing device 13 (photosensitive drum 11, charging device 12, cleaning device 15) remain held in the cartridge case 50.
It should be noted that when the developing device 13 is attached to the process cartridge 10BK, the operation is performed in the reverse order to the above-mentioned detachment procedure.

By configuring the process cartridge 10BK in this way, the time and effort involved in maintenance and replacement of the developing device 13 can be reduced.
Specifically, when performing maintenance or replacement of the developing device 13, the developing device 13 can be attached to and removed from the cartridge case 50 without taking the time and effort of removing the photosensitive drum 11 and the face plate 40 from the cartridge case 50. I can do it.

Here, as shown in FIG. 7, in the process cartridge 10BK (holding device) according to the present embodiment, the face plate 40 as a positioning member is connected to the rotation center axis X1 of the photosensitive drum 11 as the first rotating body and the second When viewed in a cross section including the rotational center axis X2 of the developing roller 13a as a rotating body, the abutting portion 40a against which the shaft portion 13a10 of the developing roller 13a abuts makes point contact with the shaft portion 13a10 (including a contact state close to point contact). ).
Specifically, the abutting portion 40a of the face plate 40 (positioning member) is formed in an arc shape (curved surface shape) when viewed in the above-mentioned cross section (the cross section shown in FIG. 7). Furthermore, when viewed three-dimensionally, the abutting portion 40a of the face plate 40 is formed into a substantially semi-cylindrical shape, as shown in FIG.
That is, in the present embodiment, the surface of the abutment portion 40a facing the shaft portion 13a10 (opposing surface) is not formed in a planar shape as shown in FIG. As shown in the figure, it is formed into a curved surface (arc shape).

On the other hand, when the abutment part 140a is formed to make line contact (or surface contact) with the shaft part 13a10, as in the face plate 140 shown as a comparative example in FIG. 9(B), when the face plate 140 is installed in the cartridge case 50 in a normal position, as shown in FIG. 9(A). In addition, if the face plate 140 is installed in an inclined position, the corner of the face plate 140 (abutment portion 140a) will easily come into contact with the shaft portion 13a10. When the face plate 140 (abutting portion 140a) hits the shaft portion 13a10 at a corner in this way, the developing roller 13a (shaft portion 13a10) is pushed relative to the corner, and The facing distance (development gap H) between the photoreceptor drum 11 and the development roller 13a deviates from the target by a minute ΔH.
In contrast, in the present embodiment, the abutment portion 40a is formed to make point contact with the shaft portion 13a10 regardless of the relative inclination of the face plate 40 with respect to the cartridge case 50. The developing gap H can be set to a desired value with high accuracy without the portion 40a hitting the shaft portion 13a10.

Note that when the face plate 40 is inclined relative to the cartridge case 50, the face plate 40 is in an inclined position with respect to the developing roller 13a (rotation center axis X2), and (1) the developing roller 13a (2) developing roller 13a (rotational center axis There is a mode in which the face plate 40 is installed in a normal attitude (or an inclined attitude) with respect to the cartridge case 50 which is installed in an inclined attitude with respect to the cartridge case 50 .
In either embodiment, the development gap H can be set with high accuracy by configuring the abutment portion 40a to make point contact with the shaft portion 13a10.
Note that the case where the face plate 40 is inclined relative to the cartridge case 50 is due to component accuracy of the cartridge case 50 and the face plate 40 (for example, accuracy such as surface accuracy and parallelism of mutual contact surfaces). ) or the assembly accuracy may be low. Furthermore, there are cases where the mechanical strength of the face plate 40 is so low that the face plate 40 is deformed and inclined.

<Modification 1>
As shown in FIG. 10(A), when the process cartridge 10BK (holding device) in Modification Example 1 is seen in the cross section previously explained in FIG. 7, the center W1 of the arc of the abutment portion 40a is 11 (first rotating body) and the position where the abutting portion 40a makes point contact (the position surrounded by a broken line), and is perpendicular to the rotation center axis X1 of the photoreceptor drum 11. Y1 is configured to intersect with Y1.
That is, the surface of the abutting portion 40a is formed in a curved shape so as to draw an arc with a radius R1 from the center W1 in FIG. 10(A).
With this configuration, even if the face plate 40 is inclined relative to the cartridge case 50 with respect to the center W1 in FIG. Easier to set with high precision.
Further, as shown in FIG. 10(B), when viewed in the cross section previously explained in FIG. Even if the surface of the abutting portion 40a is located on the center W2 in the axial direction of the bearing 45 (the position on the broken line Y2 in the figure), Similar effects can be obtained even if the surface is formed into a curved surface, such as drawing an arc with radius R2). That is, even if the face plate 40 is inclined relative to the cartridge case 50 with respect to the center W2 in FIG. Become.
Further, the process cartridge 10BK may be configured such that the center W1 and the center W2 described above coincide.
When configuring the face plate 40 to be removably installed in the cartridge case 50, such a configuration is useful because the design is based on the rotation center axis X1 of the photosensitive drum 11 in most cases.

<Modification 2>
As shown in FIG. 11, in the process cartridge 10BK (holding device) in Modification Example 2, the abutment portion 40a of the face plate 40 (positioning member) has a triangular shape when viewed in the cross section described using FIG. is formed.
That is, in the present embodiment, the surface of the abutment portion 40a facing the shaft portion 13a10 (opposed surface) is not formed in an arc shape as shown in FIG. 8, but is formed in an arc shape as shown in FIG. It is formed into a triangular shape. Furthermore, in the second modification, the abutment portion 40a of the face plate 40 is formed into a substantially triangular prism shape when viewed three-dimensionally.
Even with this configuration, the abutment portion 40a makes point contact with the shaft portion 13a10, and as shown in FIG. 11(A), the face plate 40 is installed in the cartridge case 50 in a normal posture. Of course, even when the face plate 40 is installed in an inclined position as shown in FIG. Become.
Therefore, regardless of the relative inclination of the face plate 40 with respect to the cartridge case 50, the abutting part 40a makes point contact with the shaft part 13a10, and the developing gap is maintained without the abutting part 40a making a corner contact with the shaft part 13a10. It becomes easier to set H with high accuracy.

<Modification 3>
In the process cartridge 10BK (holding device) shown in FIG. 12 in Modification 3, the face plate 40 (positioning member) is also formed to make point contact with the shaft portion 13a10.
In Modification 3, the face plate 40 is made of a metal material. This increases the mechanical strength of the face plate 40, and reduces the problem of the face plate 40 being tilted due to deformation.
Further, in the third modification, at least the surface of the abutting portion 40a that abuts against the shaft portion 13a10 of the developing roller 13a (second rotating body) is formed of a non-conductive material. Specifically, the face plate 40 itself may be formed of a non-conductive metal material, only the surface of the abutting portion 40a may be formed of a non-conductive metallic material, or the surface of the abutting portion 40a may be formed of a non-conductive material. It can be coated with a different coating. Thereby, even if a developing bias is applied to the shaft portion 13a of the developing roller 13a, it is possible to prevent the developing bias from flowing to the photosensitive drum 11 via the face plate 40.
More specifically, as shown in FIG. 12, the wall portions 50a and 50b (regulating portions) in Modification 3 are provided with a shaft portion 13a10 on the side of the face plate 40 (see FIG. A leaf spring member 42 (elastic member) is used that biases the right side of the body.
This plate spring member 42 (pressing member) is a metal plate formed in a substantially L shape and having electrical conductivity and spring properties.
On the other hand, the wall portions 50a and 50b (regulating portions) are formed with an insertion hole portion 50e into which the leaf spring member 42 is inserted so as to be elastically deformable by contact with the shaft portion 13a10. The insertion hole portion 50e is a hole portion into which the pressing portion (excluding the bent portion) of the leaf spring member 42 is inserted so as to be elastically deformable, and passes through the upper wall portion 50a. The lower wall portion 50b is a portion into which the tip portion of the leaf spring member 42 is inserted. The upper surface of the upper wall portion 50a is abutted against the bent portion of the leaf spring member 42 so as to be able to make surface contact therewith.
When the shaft portion 13a10 is not present (in a state where it is not elastically deformed), the leaf spring member 42 is in the range where the shaft portion 13a10 is planned to be installed (the shaft portion is not deformed), as shown by the broken line in FIG. (within the outside diameter). Then, with the shaft portion 13a10 installed, the leaf spring member 42 is elastically deformed as shown by the solid line in FIG. become.
As a result, the shaft portion 13a10 abuts against the abutting portion 40a (face plate 40), the distance between the shafts of the photoreceptor drum 11 and the developing roller 13a is determined, and the developing gap H is accurately set to the target value. will be done.
Here, with reference to FIG. 12, the process cartridge 10BK in Modification 3 is configured to apply a developing bias to the shaft portion 13a10 of the developing roller 13a via the plate spring member 42 (pressing member).
Specifically, the leaf spring member 42 electrically connects to the power supply 90 installed in the image forming apparatus main body 1 in conjunction with the operation of attaching and detaching the developing device 13 (process cartridge 10BK) to the image forming apparatus main body 1. It is configured to connect and disconnect. Then, with the developing device 13 (process cartridge 10BK) installed in the image forming apparatus main body 1, the leaf spring member 42 is connected to the power source 90 in the normal image forming process, as described above with reference to FIG. A predetermined developing bias is applied to the developing roller 13a through the developing roller 13a, and a developing process is performed.
In this way, by making the leaf spring member 42 function as an electrode for applying a developing bias, the device can be made smaller and at a lower cost than when such an electrode is installed exclusively. .

As described above, the process cartridge 10BK in this embodiment is a holding device that rotatably holds the photosensitive drum 11 (first rotating body) and the developing roller 13a (second rotating body), and A cartridge case 50 (housing) that rotatably supports the photosensitive drum 11 and a shaft portion 13a10 of the developing roller 13a installed in the cartridge case 50 abut against each other to determine the facing distance H between the photosensitive drum 11 and the developing roller 13a. A face plate 40 (positioning member) and a pressing member 41 that is removably installed in the cartridge case 50 (or the face plate 40) and presses the shaft portion 13a10 in a state of abutting against the face plate 40 toward the face plate 40 are provided. There is. When the face plate 40 is viewed in a cross section including the rotational center axis X1 of the photoreceptor drum 11 and the rotational center axis X2 of the developing roller 13a, the abutting portion 40a against which the shaft portion 13a10 of the developing roller 13a abuts is the shaft portion 13a10. It is formed so that it makes point contact with.
As a result, even if the face plate 40 is installed so as to be inclined relative to the cartridge case 50 of the process cartridge 10BK, the facing distance H between the photosensitive drum 11 and the developing roller 13a can be set with high precision. I can do it.

In this embodiment, the drum shaft 11a of the photosensitive drum 11 (first rotating body) is configured to be rotatably supported by the face plate 40. However, the method of supporting the first rotating body is not limited to this. For example, a convex portion formed on the face plate 40 can be rotated on a concave flange press-fitted into the end of the photoreceptor drum 11 (first rotating body). It can also be configured to fit.
Further, in this embodiment, the photosensitive drum 11 (first rotating body) is configured to be rotatably held indirectly in the cartridge case 50 (casing) via the face plate 40 (positioning member). It is also possible to configure the photosensitive drum 11 to be directly rotatably held in the cartridge case 50 (casing).
Further, in this embodiment, the pressing member 41 is removably installed in the cartridge case 50 (casing), but as in Patent Document 1, the pressing member 41 is removably installed in the face plate 40 (positioning member). You can also.
Even in such cases, the same effects as those of this embodiment can be obtained.

Further, in this embodiment, the present invention is applied to the process cartridge 10BK (holding device) in which the cartridge case 50 (housing) is formed with two walls 50a and 50b; The present invention can also be applied to a process cartridge 10BK in which wall portions 50a and 50b are not formed.
Further, in this embodiment, the present invention is applied to a process cartridge 10BK (holding device) that rotatably holds the photosensitive drum 11 as a first rotating body and the developing roller 13a as a second rotating body. However, the application of the present invention is not limited to this, and the present invention can be applied to any holding device that rotatably holds the first rotating body and the second rotating body.
Even in such cases, the same effects as those of this embodiment can be obtained.

Further, in the present embodiment, the present invention is applied to the process cartridge 10BK that includes the photoreceptor drum 11 (image carrier), the developing device 13, the charging device 12, and the cleaning device 15, but the present invention is not applied to the process cartridge 10BK. The process cartridge is not limited to this, and the present invention can be applied to any process cartridge equipped with at least a photosensitive drum (image carrier) and a developing device (developer carrier).
Even in such a case, effects similar to those of this embodiment can be obtained.
In this application, the term "process cartridge" refers to a charging device that charges an image carrier, a developing device that develops a latent image formed on the image carrier, and a cleaning device that cleans the top of the image carrier. It is defined as a unit in which at least one of these and an image carrier are integrated and configured to be removably attached to the main body of the image forming apparatus.

Note that it is clear that the present invention is not limited to this embodiment, and that this embodiment can be modified as appropriate within the scope of the technical idea of the present invention in addition to what is suggested in this embodiment. be. Further, the number, position, shape, etc. of the constituent members are not limited to those in this embodiment, and can be set to a number, position, shape, etc. suitable for implementing the present invention.

1 Image forming device (image forming device main body),
10Y, 10M, 10C, 10BK process cartridge (holding device),
11 Photosensitive drum (first rotating body, image carrier),
11a drum shaft,
13 developing device,
13a developing roller (second rotating body, developer carrier),
13a10 shaft part,
13r developing case,
40 face plate (positioning member),
40a abutting section,
41 pressing member,
45 bearing,
50 Cartridge case (casing),
H development gap (opposing distance),
X1, X2 rotation center axis,
Y1 Virtual line.

Note that the embodiments of the present invention can also be a combination of Supplementary Notes 1 to 9, for example, as shown below.
(Additional note 1)
A holding device that rotatably holds a first rotating body and a second rotating body,
a casing that rotatably supports the first rotating body;
a positioning member that is installed in the casing and that a shaft portion of the second rotating body abuts against to determine a facing distance between the first rotating body and the second rotating body;
a pressing member that is removably installed on the housing or the positioning member and presses the shaft portion in a state of abutting against the positioning member toward the positioning member;
Equipped with
When the positioning member is viewed in a cross section including the rotation center axis of the first rotation body and the rotation center axis of the second rotation body, the abutting portion against which the shaft portion of the second rotation body abuts is located on the shaft. A holding device characterized in that it is formed so as to make point contact with the portion.
(Additional note 2)
The holding device according to appendix 1, wherein the abutting portion of the positioning member is formed in an arc shape when viewed in the cross section.
(Additional note 3)
When viewed in the cross section, the center of the circular arc of the abutting portion passes through a point contacting the central axis of rotation of the first rotating body with the central axis of rotation of the first rotating body. The holding device according to appendix 2, wherein the holding device is an intersection point of orthogonal virtual lines.
(Additional note 4)
The positioning member includes a bearing that rotatably holds the first rotating body,
The casing rotatably supports the first rotating body via the positioning member,
Supplementary Note 2 or 3, wherein when viewed in the cross section, the center of the circular arc of the abutting portion is located on the rotation center axis of the first rotating body and at the center position of the bearing in the axial direction. The holding device described in .
(Appendix 5)
The holding device according to appendix 1, wherein the abutting portion of the positioning member is formed in a triangular shape when viewed in cross section.
(Appendix 6)
The holding device according to any one of appendices 1 to 5, wherein the positioning member is made of a metal material.
(Appendix 7)
6. The holding device according to appendix 6, wherein at least a surface of the abutting portion of the positioning member that abuts against the shaft portion of the second rotating body is formed of a non-conductive material.
(Appendix 8)
A process cartridge as a holding device according to any one of appendices 1 to 7, which is removably installed in an image forming apparatus main body,
an image carrier as the first rotating body;
a developing device in which a developer carrier serving as the second rotating body is rotatably held and is removably installed in the process cartridge;
A process cartridge characterized by being equipped with.
(Appendix 9)
An image forming apparatus characterized in that the holding device according to any one of appendices 1 to 7 or the process cartridge according to appendix 8 is removably installed.

JP2022-46342A

Claims (9)

A holding device that rotatably holds a first rotating body and a second rotating body,
a casing that rotatably supports the first rotating body;
a positioning member that is installed in the casing and that a shaft portion of the second rotating body abuts against to determine a facing distance between the first rotating body and the second rotating body;
a pressing member that is removably installed on the housing or the positioning member and presses the shaft portion in a state of abutting against the positioning member toward the positioning member;
Equipped with
When the positioning member is viewed in a cross section including the rotation center axis of the first rotation body and the rotation center axis of the second rotation body, the abutting portion against which the shaft portion of the second rotation body abuts is located on the shaft. A holding device characterized in that it is formed so as to make point contact with the portion. The holding device according to claim 1, wherein the abutting portion of the positioning member is formed in an arc shape when viewed in the cross section. When viewed in the cross section, the center of the circular arc of the abutting portion passes through a point contacting the central axis of rotation of the first rotating body with the central axis of rotation of the first rotating body. 3. The holding device according to claim 2, wherein the holding device is an intersection point of orthogonal virtual lines. The positioning member includes a bearing that rotatably holds the first rotating body,
The casing rotatably supports the first rotating body via the positioning member,
When viewed in the cross section, the center of the circular arc of the abutting portion is located on the rotation center axis of the first rotating body and at the center position of the bearing in the axial direction. The holding device according to item 3. 2. The holding device according to claim 1, wherein the abutting portion of the positioning member has a triangular shape when viewed in cross section. 3. The holding device according to claim 1, wherein the positioning member is made of a metal material. 7. The holding device according to claim 6, wherein at least a surface of the abutting portion of the positioning member that contacts the shaft portion of the second rotating body is formed of a non-conductive material. The process cartridge as a holding device according to claim 1 or 2, which is installed removably with respect to an image forming apparatus main body,
an image carrier as the first rotating body;
a developing device in which a developer carrier serving as the second rotating body is rotatably held and is removably installed in the process cartridge;
A process cartridge characterized by being equipped with. An image forming apparatus, wherein the process cartridge according to claim 8 is removably installed.

Images