JP2017191331A - Process unit and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device with which a developer carrier can be arranged at a target position with respect to a photoreceptor.SOLUTION: There is provided a process unit comprising: a photoreceptor unit U1 that supports a photoreceptor 2; a developing unit U2 that supports a developing roller 41; and a connection part that connects the photoreceptor unit U1 and developing unit U2, wherein a plurality of urging members 52 and 53 urging the developing roller 41 toward the photoreceptor are provided at one end in the axial direction of the developing roller, and the plurality of urging members 52 and 53 are stretched over while being pulled between the photoreceptor unit U1 and developing unit U2.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a process unit and an image forming apparatus.

  In an image forming apparatus such as a copying machine or a printer, in order to prevent the occurrence of abnormal images such as unevenness in image density or defects, toner as a developer is uniformly transferred from the developing roller to the surface of the photosensitive member without unevenness. It is necessary. For this purpose, the photosensitive member and the developing roller must be in contact with each other at a target position with a uniform contact pressure in the axial direction.

  In order to stably bring the developing roller into contact with the photosensitive member, for example, a developing unit (developing device) having a developing roller and a photosensitive member unit having a photosensitive member are arranged on both end sides in the axial direction of the developing roller. A configuration is known in which the development unit is urged toward the photosensitive unit by a biasing member such as a spring (see Patent Document 1 below).

  If the position of the developing roller with respect to the photosensitive member is shifted, the developing roller cannot be disposed at the target position, and an abnormal image may be generated.

  Accordingly, in view of such circumstances, the present invention intends to provide a process unit and an image forming apparatus capable of disposing a developer carrying member at a target position with respect to a photosensitive member.

  In order to solve the above-described problems, a process unit according to the present invention includes a photosensitive unit that supports a photosensitive member, a developing unit that supports a developing roller, and a connecting portion that connects the photosensitive unit and the developing unit. A plurality of urging members for urging the developing roller toward the photosensitive member side are provided on one end side in the axial direction of the developing roller, and the urging members include the photosensitive unit and the developing unit. It is characterized by being spanned in a tensioned state.

  According to the present invention, the developer carrying member can be disposed at a target position with respect to the photosensitive member.

1 is a schematic configuration diagram illustrating an embodiment of an image forming apparatus to which the present invention is applied. It is a figure which shows the state which opened the upper cover. It is a figure which shows the state which opened the upper cover and the intermediate | middle cover. It is a schematic sectional drawing of a process unit. FIG. 3 is a diagram illustrating a driving system for a photoconductor unit and a developing unit. FIG. 3 is a diagram illustrating a driving system of a photosensitive unit, a developing unit, and an apparatus main body. It is the perspective view which looked at the process unit from the drive side. It is the perspective view which looked at the process unit from the non-driving side. It is a figure for demonstrating arrangement | positioning of two coil springs by the side opposite to a drive. It is a perspective view which shows the structure of the non-driving side of a process unit. 2A and 2B are diagrams showing the opposite driving sides of the photosensitive unit and the developing unit, in which FIG. 1A shows a state before the photosensitive unit and the developing unit are assembled, and FIG. 2B shows the photosensitive unit and the developing unit. It is a figure which shows the state which assembled | attached. It is a figure which shows the example which comprised the image development side electrode member with the leaf | plate spring. It is a figure which shows the example which comprised the photosensitive side electrode member with the electrode member which provided the conductor in the front-end | tip of a coil spring. In the present invention, it is a diagram showing a contact state of the developing roller with respect to the photoreceptor when twisting occurs. In a comparative example, it is a figure which shows the contact state of the developing roller with respect to the photoreceptor when twist arises.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each of the drawings for explaining the embodiments of the present invention, constituent elements such as members and components having the same function or shape are described once by giving the same reference numerals as much as possible. Then, the explanation is omitted.

  First, an overall configuration and operation of a color laser printer according to an embodiment of the present invention will be described with reference to FIG. However, the present invention is not limited to this. The configuration of the present invention can also be applied to an image forming apparatus such as a monochrome printer, other printers, a copier, a facsimile, or a complex machine thereof.

  As shown in FIG. 1, four process units 1Y, 1M, 1C, and 1Bk as image forming units are detachably mounted on an apparatus main body (image forming apparatus main body) 100 of the color laser printer. Each process unit 1Y, 1M, 1C, 1Bk contains toners of different colors of yellow (Y), magenta (M), cyan (C), and black (Bk) corresponding to the color separation components of the color image. Other than that, the configuration is the same.

  Specifically, each of the process units 1Y, 1M, 1C, and 1Bk converts the photoreceptor 2, the charging roller 3 as a charging unit that charges the surface of the photoreceptor 2, and the latent image on the photoreceptor 2 into a visible image. The developing device 4 is a developing unit that performs cleaning, and the cleaning blade 5 is a cleaning unit that cleans the surface of the photoreceptor 2. An exposure device 6 for exposing the surface of the photoconductor 2 is provided at a position facing each photoconductor 2. In the present embodiment, an LED unit is used as the exposure device 6.

  A toner cartridge 30 as a developer container that contains toner as a developer is detachably mounted above each developing device 4. Each toner cartridge 30 contains toner of the same color as the toner in the corresponding developing device 4. When the toner in the developing device 4 falls below a predetermined amount, the toner is supplied from the toner cartridge 30. ing.

  A transfer device 7 is disposed below each photoconductor 2. The transfer device 7 has an intermediate transfer belt 8 formed of an endless belt as an intermediate transfer member. The intermediate transfer belt 8 is stretched around a driving roller 9 and a driven roller 10 as support members, and when the driving roller 9 rotates counterclockwise in the drawing, the intermediate transfer belt 8 travels (rotates) in a circle. It is configured as follows.

  A primary transfer roller 11 as a primary transfer unit is disposed at a position facing each photoconductor 2. Each primary transfer roller 11 presses the inner peripheral surface of the intermediate transfer belt 8 at each position, and a primary transfer nip is formed at a place where the pressed portion of the intermediate transfer belt 8 and each photoconductor 2 are in contact with each other. Has been. Each primary transfer roller 11 is connected to a power source (not shown), and a predetermined direct current voltage (DC) and / or alternating current voltage (AC) is applied to the primary transfer roller 11.

  A secondary transfer roller 12 as a secondary transfer unit is disposed at a position facing the drive roller 9. The secondary transfer roller 12 presses the outer peripheral surface of the intermediate transfer belt 8, and a secondary transfer nip is formed at a location where the secondary transfer roller 12 and the intermediate transfer belt 8 are in contact with each other. Similarly to the primary transfer roller 11, the secondary transfer roller 12 is connected to a power source (not shown), and a predetermined DC voltage (DC) and / or AC voltage (AC) is applied to the secondary transfer roller 12. It has become so.

  A belt cleaning device 13 for cleaning the surface of the intermediate transfer belt 8 is disposed on the outer peripheral surface on the right end side of the intermediate transfer belt 8 in the drawing. A waste toner transfer hose (not shown) extending from the belt cleaning device 13 is connected to an entrance of a waste toner container 14 disposed below the transfer device 7.

  A lower part of the apparatus main body 100 is provided with a paper feed tray 15 that stores paper P as a recording medium, a paper feed roller 16 that feeds the paper P from the paper feed tray 15, and the like. Here, the paper P includes thick paper, postcard, envelope, plain paper, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, and the like. Further, an OHP sheet, an OHP film, or the like can be used as a recording medium.

  A pair of paper discharge rollers 17 for discharging the paper to the outside and a paper discharge tray 18 for stocking the paper discharged by the paper discharge roller 17 are provided on the upper portion of the apparatus main body 100.

  In the apparatus main body 100, a transport path R for transporting the paper P from the paper feed tray 15 through the secondary transfer nip to the paper discharge tray 18 is disposed. In the transport path R, a pair of registration rollers 19 are provided on the upstream side in the paper transport direction from the position of the secondary transfer roller 12 as a timing roller for transporting the paper to the secondary transfer nip by measuring the transport timing. Yes. In addition, a fixing device 20 that fixes an image on a sheet is provided downstream of the position of the secondary transfer roller 12 in the sheet conveyance direction.

Next, a basic operation of the printer according to the present embodiment will be described with reference to FIG.
When the image forming operation is started, the photosensitive members 2 of the process units 1Y, 1M, 1C, and 1Bk are rotated in the clockwise direction in FIG. 1, and the surface of each photosensitive member 2 is made to have a predetermined polarity by the charging roller 3. It is charged like this. Based on image information from a reading device or a computer (not shown), the exposure device 6 irradiates the charged surface of each photoconductor 2 with laser light, and an electrostatic latent image is formed on the surface of each photoconductor 2. At this time, the image information to be exposed on each photoconductor 2 is single-color image information obtained by separating a desired full-color image into color information of yellow, magenta, cyan, and black. As the electrostatic latent image formed on the photosensitive member 2 is supplied with toner by each developing device 4, the electrostatic latent image is visualized (visualized) as a toner image.

  When the image forming operation is started, the intermediate transfer belt 8 is driven to rotate by the drive roller 9 that stretches the intermediate transfer belt 8 being rotated. Also, a primary transfer nip between each primary transfer roller 11 and each photoreceptor 2 is applied to each primary transfer roller 11 by applying a constant voltage or a voltage controlled by a constant current opposite to the charging polarity of the toner. A transfer electric field is formed.

  Thereafter, when each color toner image on the photoconductor 2 reaches the primary transfer nip as the photoconductor 2 rotates, the toner image on each photoconductor 2 is formed by the transfer electric field formed in the primary transfer nip. Are sequentially superimposed and transferred onto the intermediate transfer belt 8. Thus, a full-color toner image is carried on the surface of the intermediate transfer belt 8. Further, the toner on each photoreceptor 2 that could not be transferred to the intermediate transfer belt 8 is removed by the cleaning blade 5.

  In the lower part of the apparatus main body 100, the paper feed roller 16 starts to rotate, and the paper P is sent out from the paper feed tray 15 to the transport path R. The paper P sent to the transport path R is temporarily stopped by the registration roller 19.

  Thereafter, rotation of the registration roller 19 is started at a predetermined timing, and the paper P is conveyed to the secondary transfer nip in accordance with the timing when the toner image on the intermediate transfer belt 8 reaches the secondary transfer nip. At this time, a transfer voltage having a polarity opposite to the toner charging polarity of the toner image on the intermediate transfer belt 8 is applied to the secondary transfer roller 12, thereby forming a transfer electric field in the secondary transfer nip. . Then, the toner images on the intermediate transfer belt 8 are collectively transferred onto the paper P by this transfer electric field. The residual toner on the intermediate transfer belt 8 that could not be transferred onto the paper P is removed by the belt cleaning device 13, and the removed toner is transported to the waste toner container 14 and collected.

  Thereafter, the paper P on which the toner image is transferred is conveyed to the fixing device 20, and the toner image on the paper P is fixed on the paper P in the fixing device 20. Then, the paper P is discharged out of the apparatus by the pair of paper discharge rollers 17 and stocked on the paper discharge tray 18.

  The above description is an image forming operation when a full-color image is formed on a sheet. A single-color image is formed using any one of the four process units 1Y, 1M, 1C, and 1Bk, or two Alternatively, it is possible to form two-color or three-color images using three process units.

  As shown in FIG. 1, the printer according to the present embodiment includes an upper cover 101 as a first cover provided on the upper portion of the apparatus main body 100 and a first cover provided on the inner side (lower side) of the upper cover 101. And an intermediate cover 102 as two covers. The upper cover 101 and the intermediate cover 102 are configured to be openable and closable by rotating around support shafts 103 and 104 provided in the apparatus main body 100, respectively. 2 shows a state in which the upper cover 101 is opened, and FIG. 3 further shows a state in which the intermediate cover 102 is opened.

  The intermediate cover 102 is formed with a container mounting portion 120 to which a plurality of toner cartridges 30 can be mounted. The unit mounting portion 130 formed on the inner side (lower side) of the intermediate cover 102 can accommodate the process units 1Y, 1M, 1C, and 1Bk for each color.

  As shown in FIG. 2, when the upper cover 101 is opened, each toner cartridge 30 can be attached to and detached from the intermediate cover 102 from above.

  Further, as shown in FIG. 3, when the intermediate cover 102 is opened, the toner cartridges 30 can be integrally retracted from above the process units 1Y, 1M, 1C, and 1Bk. At this time, since each exposure device 6 is retracted from above each photoconductor 2 together with the intermediate cover 102, each process unit 1Y, 1M, 1C, 1Bk can be attached and detached from above. As described above, in the present embodiment, the process units 1Y, 1M, 1C, and 1Bk can be attached and detached without removing the toner cartridge 30 from the intermediate cover 102, and exchanging workability is excellent.

FIG. 4 is a schematic sectional view of the process unit.
In the present embodiment, the process unit 1 (the alphabets Y, M, C, and Bk indicating the respective colors are omitted) is mainly composed of two modules. One is a photoreceptor unit (first unit) U1 having the photoreceptor 2, the charging roller 3, the cleaning blade 5, and the like. The other is a developing unit (second unit) U2 having the developing device 4.

  The developing unit U2 (developing device 4) includes a housing 40 that contains toner and the like, a developing roller 41 as a developer carrying member that carries the toner, and a developer supply member that supplies toner to the developing roller 41. A supply roller 42; a regulating blade 43 as a regulating member that regulates the thickness of toner carried on the developing roller 41; a conveying screw 44 as a conveying member that conveys toner; and an agitating member that agitates toner An agitator 45 is provided.

  An opening 40c is formed in the lower portion of the housing 40 facing the photoreceptor 2, and a developing roller 41 is rotatably provided in the opening 40c. The developing roller 41 is made of a metal core, an elastic layer made of an elastic member or a foamed elastic member disposed on the outer periphery of the core, an acrylic resin, a silicone resin, or the like disposed on the outer periphery of the elastic layer. And a surface layer (resin coat layer). The developing roller 41 may not have a surface layer.

  The supply roller 42 is constituted by a sponge roller in which an elastic layer made of a foamed elastic member is disposed on the outer periphery of a metal cored bar. Examples of the material for the foamed elastic member include flexible urethane foam, silicone, and foamed polymer. Moreover, you may use what adjusted the resistance value by adding a electrically conductive material to these materials. The supply roller 42 is in contact with the developing roller 41, and a nip (hereinafter referred to as “supply nip”) is formed between the rollers 41 and 42.

  The regulating blade 43 is made of, for example, a metal plate such as SUS having a thickness of about 0.1 mm. The front end of the regulating blade 43 is in contact with the surface of the developing roller 41 to form a nip (hereinafter referred to as “regulating nip”).

  When an instruction to start an image forming operation is given, the toner in the housing 40 is stirred by the agitator 45 and supplied to the supply roller 42 by the conveying screw 44. The toner supplied to the supply roller 42 is frictionally charged by the friction between the supply roller 42 and the developing roller 41 at the supply nip and is supplied to the surface of the developing roller 41.

  The toner carried on the developing roller 41 passes through the regulation nip of the regulation blade 43, thereby being triboelectrically charged at the same time as the thickness of the toner layer is regulated. When the toner on the developing roller 41 is conveyed to a position (development region) facing the photoconductor 2, the toner is applied on the photoconductor 2 by the force of the electric field generated between the photoconductor 2 and the developing roller 41. A toner image is formed by transferring to an electrostatic latent image.

  Next, a drive system for the photosensitive unit and the developing unit will be described with reference to FIGS. As shown in FIG. 5, the axial ends of the developing roller 41 and the supply roller 42 are rotatably supported by a pair of side wall portions 40a and 40b included in the housing 40 of the developing unit U2. Further, both ends in the axial direction of the photoreceptor 2 are rotatably supported by a pair of support walls 50a and 50b included in the housing 50 of the photoreceptor unit U1.

  A photoreceptor gear G1 is coaxially provided at one end of the photoreceptor 2. A developing gear G2 is coaxially provided at one end of the developing roller 41 on the same side, and the developing gear G2 meshes with the photoconductor gear G1 so that power can be transmitted between them.

  In FIG. 6, G3 is a drive gear of a drive motor M provided in the apparatus main body, and G4 to G6 are a plurality of transmission gears provided in the apparatus main body. When the process unit 1 is mounted on the apparatus main body, as shown in FIG. 6, the photoconductor gear G1 is connected to the drive gear G3 via a plurality of transmission gears G4 to G6. When the driving motor M is driven in this state, the driving force is transmitted from the driving gear G3 to the photosensitive member gear G1 via the transmission gears G4 to G6, and further to the developing gear G2. Yes.

  As shown in FIG. 5, a supply gear G7 that meshes with the developing gear G2 is also provided coaxially at one end of the supply roller 42, and the supply roller 42 is connected to the developing roller 41 via the supply gear G7. The driving force is transmitted from. A transmission gear G8 for transmitting a driving force to the conveying screw 44 and the agitator 45 is provided at the end of the supply roller 42 opposite to the end where the supply gear G7 is provided. The transmission gear G8 is provided outside the right side wall portion 40b of the developing unit U2 in FIG. 5 and is covered with a gear cover 46.

FIG. 7 is a perspective view of the process unit as viewed from the side on which the photoconductor gear and the development gear are provided (hereinafter referred to as “drive side”).
As shown in FIG. 7, a pin-shaped rotating shaft 40d having a circular cross section is provided at the lower part of the side wall 40a on the driving side of the developing unit U2. On the other hand, a circular hole 50c into which the rotating shaft 40d of the developing unit U2 can be inserted is provided in the lower part of the driving side support wall 50a of the photosensitive unit U1. By inserting the rotating shaft 40d into the hole 50c, the driving side wall portion 40a of the developing unit U2 is illustrated with respect to the driving side support wall 50a of the photosensitive unit U1 through the rotating shaft 40d and the hole 50c. 7 is assembled so as to be rotatable in the directions of arrows A and B.

  Further, a drive side coil spring 51 as an urging member is provided on the drive side side wall portion 40a of the developing unit U2. Of the both ends of the drive side coil spring 51, one is locked to a locking portion 40e provided on the upper portion of the side wall portion 40a of the developing unit U2, and the other is provided on the upper portion of the support wall 50a of the photosensitive unit U1. The locking portion 50d is locked. The driving side coil spring 51 is stretched between the engaging portions 40e and 50d, and the developing roller 41 is biased toward the photosensitive member 2 by the tensile force of the driving side coil spring 51. .

FIG. 8 is a perspective view of the process unit as viewed from the side opposite to the driving side (hereinafter referred to as “non-driving side”).
As shown in FIG. 8, a pin-shaped rotational movement shaft 40f having a circular cross section is provided below the side wall portion 40b on the side opposite to the driving side of the developing unit U2 and opposite to the driving side rotational shaft 40d. ing. On the other hand, a linear groove 50e into which the rotational movement shaft 40f of the developing unit U2 can be inserted is provided below the support wall 50b on the counter drive side of the photoconductor unit U1 so as to approach and separate from the photoconductor 2. ing. By inserting the rotational movement shaft 40f into the groove 50e, the side wall portion 40b on the counter drive side of the developing unit U2 is supported on the counter drive side support wall 50b of the photoreceptor unit U1 via the rotational movement shaft 40f and the groove 50e. On the other hand, it can be moved in the direction of arrows C and D in the figure, and can be rotated in the directions of arrows S and T in the figure. Here, the groove 50e is a through-hole penetrating the support wall 50b on the non-driving side, but may have a groove shape having a bottom.

  Further, a first counter driving side coil spring 52 and a second counter driving side coil spring 53 are provided as biasing members on the counter driving side of the developing unit U2. The first counter driving side coil spring 52 is provided on the upper side of the developing unit U2 on the counter driving side, and the second counter driving side coil spring 53 is provided on the lower side of the developing unit U2 on the counter driving side.

  Specifically, one end of the first counter driving side coil spring 52 is locked to a locking portion 46a provided on the upper portion of the gear cover 46 of the developing unit U2, and the other end is counter driven of the photosensitive unit U1. It is latched by the latching | locking part 50f provided in the upper part of the cover member 56 (refer FIG. 7) attached to the outer side of the side support wall 50b. In FIG. 8, the cover member 56 is not shown. As described above, the first counter driving side coil spring 52 is stretched between the two locking portions 46a and 50f, and the developing roller is pulled by the tensile force of the first counter driving side coil spring 52. 41 is urged toward the photosensitive member 2 side.

  One end portion of the second counter driving side coil spring 53 is engaged with the rotational movement shaft 40f provided at the lower portion of the side wall portion 40b on the counter driving side of the developing unit U2, and the other end portion of the photosensitive unit U1. It is latched by the latching | locking part 50g provided in the lower part of the support wall 50b by the side of a counter drive. The second counter driving side coil spring 53 is stretched between the rotary moving shaft 40f and the locking portion 50g, and the tensile force of the second counter driving side coil spring 53 is also developed by the developing roller 41. Acts as an urging force for urging the photosensitive member 2 toward the photosensitive member 2. Here, the rotational movement shaft 40f also functions as a locking portion that locks one end of the second counter-driving side coil spring 53, but a separate locking portion may be provided.

  As described above, in the present embodiment, the developing unit U2 is urged against the photosensitive unit U1 on both the driving side and the counter driving side by the driving side coil spring 51 and the counter driving side coil springs 52 and 53. As a result, the developing roller 41 is urged toward the photoconductor 2 at both axial end portions thereof, and comes into contact with the photoconductor 2 with a predetermined contact pressure. The biasing forces of the driving side coil spring 51 and the counter driving side coil springs 52 and 53 are adjusted so that the contact pressure of the developing roller 41 with respect to the photosensitive member 2 is uniform in the axial direction.

  Further, as shown in FIG. 9, in this embodiment, the two urging members on the counter driving side (the first counter driving side coil spring 52 and the second counter driving side coil spring 53) are in contact with each other. The contact state of the developing roller 41 with respect to the photosensitive member 2 is stabilized by disposing the body 2 and the developing roller 41 on opposite sides with respect to the straight lines L passing through the rotation centers O1 and O2.

  Further, as shown in FIG. 8, on the non-driving side, two electrode members 54 constituting a conduction path for supplying power from a power source (high voltage base) (not shown) on the apparatus main body side to the developing roller 41 are provided. , 55 are provided. One electrode member 54 is attached to the support wall 50b on the counter drive side of the photoreceptor unit U1, and the other electrode member 55 is attached to the gear cover 46 of the developing unit U2. As described above, the conductive path is divided into the electrode member 54 on the photosensitive unit U1 side and the electrode member 55 on the development unit U2 side, so that the assemblability, operability, and exchange of each unit U1, U2 are made. Improves. In the following description, the electrode member 54 on the photoreceptor unit U1 side is referred to as a photosensitive side electrode member 54, and the electrode member 55 on the development unit U2 side is referred to as a development side electrode member 55.

FIG. 10 is a perspective view showing the configuration of the process unit on the non-driving side.
In FIG. 10, the support wall 50b on the counter-drive side of the photoconductor unit U1 shown in FIG. 8 is not shown.
The photosensitive side electrode member 54 and the development side electrode member 55 are each formed by bending a thin metal plate. The photosensitive-side electrode member 54 includes an inner portion 54a disposed on the inner side of the support wall 50b on the counter driving side of the photoconductor unit U1, an outer portion 54b disposed on the outer side of the supporting wall 50b on the counter driving side, It has a bent part 54c that connects the inner part 54a and the outer part 54b. Similarly, the development-side electrode member 55 includes an inner portion 55a disposed inside the gear cover 46 of the development unit U2, an outer portion 55b disposed outside the gear cover 46, an inner portion 55a, and an outer portion. And a bent portion 55c for connecting to 54b.

  The development-side electrode member 55 is in contact with the shaft end portion (end portion of metal cored bar) 41a of the developing roller 41 at the inner side portion 55a. The development side electrode member 55 is in contact with the inner side portion 54a of the photosensitive side electrode member 54 at the outer side portion 55b. The outer portion 54b of the photosensitive electrode member 54 comes into contact with an electrode member (not shown) provided on the apparatus main body side when the process unit 1 is mounted on the apparatus main body.

11A is a diagram showing a state before the photosensitive unit and the developing unit are assembled, and FIG. 11B is a diagram showing a state in which the photosensitive unit and the developing unit are assembled.
As shown in FIG. 11A, the inner side 54a of the photosensitive-side electrode member 54 includes a parallel part 54a1 parallel to the inner surface of the support wall 50b on the counter drive side of the photoconductor unit U1, and the inner surface of the support wall 50b on the counter drive side. And an inclined portion 54a2 inclined with respect to the angle. The inclined portion 54a2 is a leaf spring that is inclined so as to be separated from the inner surface of the support wall 50b on the counter drive side toward the assembly direction H of the developing unit U2 with respect to the photoreceptor unit U1. For this reason, the inclined portion 54a2 can be elastically deformed in the direction of approaching and separating from the support wall 50b on the counter driving side. The tip of the inclined portion 54a2 is disposed on the inner side of the surface J on which the outer portion 55b of the developing-side electrode member 55 is disposed when the developing unit U2 is assembled to the photoreceptor unit U1. Thus, when the developing unit U2 is assembled, the inclined portion 54a2 comes into contact with the outer side portion 55b of the developing side electrode member 55.

  As shown in FIG. 11B, when the developing unit U2 is assembled, when the outer portion 55b of the developing side electrode member 55 contacts the inclined portion 54a2 of the photosensitive side electrode member 54, the inclined portion 54a2 is pushed outward. Elastically deforms. In the state where the assembly of the developing unit U2 is completed, the inclined portion 54a2 is brought into contact with the outer side portion 55b of the developing-side electrode member 55 with a predetermined contact pressure by the restoring force, thereby ensuring electrical conductivity. When the photosensitive side electrode member 54 and the development side electrode member 55 are made of SUS material, the contact pressure is preferably 0.5 N or more in order to reduce the conduction resistance at the contact portion K of each other. Further, since the inclined portion 54a2 can be elastically displaced in the axial direction of the developing roller 41 at the contact portion K with the outer side portion 55b of the developing side electrode member 55, it is assumed that the developing unit U2 with respect to the photosensitive unit U1 is temporarily moved. Even if the assembly position is displaced in the axial direction of the developing roller 41, the inclined portion 54a2 can be displaced following the displacement, and the contact state can be maintained satisfactorily.

  As described above, in the present embodiment, the photosensitive side electrode member 54 is configured by a plate spring that can be elastically deformed. On the contrary, as shown in FIG. 12, the development side electrode member 55 is configured by a plate spring. May be. In this case, since the developing-side electrode member 55 can be elastically deformed in the axial direction of the developing roller 41, even if the assembly position of the developing unit U2 with respect to the photosensitive unit U1 is shifted in the axial direction of the developing roller 41, the shift On the other hand, the development side electrode member 55 can follow and be displaced, and it is possible to maintain a good contact state. Further, both the developing side electrode member 55 and the photosensitive side electrode member 54 may be configured to be elastically deformable in the axial direction of the developing roller 41. When at least one of the photosensitive-side electrode member 54 and the development-side electrode member 55 is configured by a leaf spring, the contact surface of the leaf spring is formed into a curved surface so as to avoid the influence of edge burrs and the like, and the frictional force due to the contact is reduced. Can be reduced.

  Further, as shown in FIG. 13, the photosensitive-side electrode member 54 may be configured by an electrode member in which a conductor 54e made of metal or the like is provided at the tip of a coil spring 54d instead of the leaf spring. In this case, when the developing unit U2 is assembled, the developing-side electrode member 55 comes into contact with the conductor 54e and moves outward to compress the coil spring 54d. Due to the restoring force of the compressed coil spring 54d, the conductor 54e contacts the developing-side electrode member 55 with a predetermined contact pressure. Further, in this case, by making the contact surface of the conductor 54e curved, the frictional force due to the contact can be reduced as described above. Although not shown, contrary to the example shown in FIG. 13, the development-side electrode member 55 may be composed of an electrode member made up of a coil spring and a conductor provided at the tip thereof.

Here, a comparative example having a configuration different from that of the present invention will be described.
In the embodiment of the present invention, the developing unit U2 is slidable with respect to the photoreceptor unit U1 via the rotational movement shaft 40f and the groove 50e on the counter drive side. In the comparative example shown in FIG. On the non-driving side, the developing unit U2 does not slide with respect to the photoreceptor unit U1, but can simply rotate via the rotating shaft 40u inserted into the hole 50u. In such a configuration, if a twist occurs between the left and right side plates on the apparatus main body side where the process unit is mounted, and a relative twist occurs between both sides of each unit U1, U2, the developing roller for the photosensitive member 2 is developed. The abutting position 41 deviates from the normal abutting position. Specifically, in FIG. 15, (a) shows a state in which each unit U1, U2 is not twisted, but as shown in FIGS. 15 (b), (c), both sides of each unit U1, U2 are shown. When a relative twist occurs in the direction indicated by the arrows in the figure (the rotation direction about the rotation axis of the photosensitive member 2), the respective contact positions V1 on the opposite ends of the developing roller 41 with respect to the photosensitive member 2 , V2 varies in the circumferential direction of the photosensitive member 2. This is because in the configuration shown in FIG. 15, the developing unit U2 follows the twist of the photosensitive unit U1 because the developing unit U2 cannot slide relative to the photosensitive unit U1 on the non-driving side.

  In contrast, in the embodiment of the present invention shown in FIG. 14, as shown in FIGS. 14B and 14C, even if the photosensitive unit U1 is twisted, the rotational movement shaft 40f is formed in the groove 50e on the non-driving side. By sliding within, the developing unit U2 can be prevented from following the twist of the photosensitive unit U1. As a result, the contact positions V1 and V2 of the developing roller 41 with respect to the photoreceptor 2 can be maintained at the same position on the driving side and the non-driving side.

  As described above, in the present invention, the developing unit U2 is slidable with respect to the photoreceptor unit U1 via the rotational movement shaft 40f and the groove 50e, so that the left and right sides of the apparatus main body side to which the process unit is mounted are arranged. Even if the twist occurs between the side plates, the influence of the twist on the contact state of the developing roller 41 can be reduced. As a result, the developing roller 41 can be disposed at a target position with respect to the photosensitive member 2, and the occurrence of an abnormal image can be prevented. In particular, in the present embodiment, the urging member (second counter driving side coil spring 53) is directly attached to the rotational movement shaft 40f, so that the rotational movement shaft 40f moving along the groove 50e is efficiently attached. I try to show power.

  In addition, this invention is not limited to the above-mentioned embodiment, Of course, a various change can be added in the range which does not deviate from the summary of this invention. In the above-described embodiment, the developing unit U2 is provided with the rotation shaft 40d and the rotational movement shaft 40f, and the photoconductor unit U1 is provided with the hole 50c and the groove 50e, but conversely, the hole and groove are provided in the developing unit U2. The photoreceptor unit U1 may be provided with a rotational shaft and a rotational movement shaft inserted into these. In addition, the present invention is not limited to a configuration in which the developing roller is in contact with the photosensitive member, that is, a developing device using a one-component developer. Therefore, the present invention can also be applied to a developing device using a two-component developer.

1 (1Y, 1M, 1C, 1Bk) Process unit 2 Photoconductor 4 Developing device 40a Side wall 40b Side wall 40d Rotating shaft 40f Rotating moving shaft 41 Developing roller (developer carrier)
50a Support wall 50b Support wall 50c Hole 50e Groove 51 Drive side coil spring (biasing member)
52 1st counter drive side coil spring (urging member)
53 Second counter driving side coil spring (urging member)
L A straight line passing through each rotation center of the photoconductor and the developing roller O1 A rotation center of the photoconductor O2 A rotation center of the developing roller

JP 2013-20233 A

Claims (8)

A photoreceptor unit for supporting the photoreceptor,
A developing unit for supporting the developing roller;
A connecting portion for connecting the photosensitive unit and the developing unit,
A plurality of urging members for urging the developing roller toward the photoconductor side are provided on one end side in the axial direction of the developing roller,
The process unit, wherein the plurality of urging members are stretched between the photosensitive unit and the developing unit.   The process unit according to claim 1, wherein the plurality of urging members are disposed on opposite sides of a contact portion between the photoconductor and the developing roller.   The process unit according to claim 1, wherein the plurality of urging members are arranged on opposite sides of a straight line passing through a rotation center of the photoconductor and a rotation center of the developing roller.   4. The urging member is pulled between a first locking portion provided in the photosensitive unit and a second locking portion provided in the developing unit. A process unit according to claim 1.   5. The photoconductor unit and the development unit are connected to each other by inserting a protrusion provided in the development unit into a hole provided in the photoconductor unit. Process unit as described in   6. The process unit according to claim 1, wherein the plurality of urging members are provided on a side opposite to a driving side where a driving force is transmitted to the photoconductor and the developing roller. On the side where the plurality of urging members are provided, a protrusion provided in the developing unit is inserted into a groove provided in the photosensitive unit, thereby connecting the photosensitive unit and the developing unit. And
7. The process unit according to claim 1, wherein the protruding portion is movable in a direction of approaching and separating from the photosensitive member within the groove.   An image forming apparatus comprising the process unit according to claim 1.

Images