JP2017215362A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can suppress a reduction in image quality.SOLUTION: Driving positioning convex parts 41a and 42a of a driving device 40 driving a photoreceptor 2 being a rotating body are fit into driving positioning concave parts 35a and 36a provided in a side wall part 38 of a transfer frame at which a process cartridge being a removal unit is positioned, and thereby the driving device 40 is positioned relative to the transfer frame. The driving device 40 and process cartridge are thus positioned relative to the transfer frame of a transfer unit being an opposing rotating body unit.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an image forming apparatus.

  An image forming apparatus such as a printer, a copying machine, or a fax machine includes an image carrier that is a rotating body and process means for forming an image on the image carrier to facilitate maintenance. There is known a process cartridge having a process cartridge which is an attachable / detachable unit.

  Patent Document 1 describes an image forming apparatus that attaches and detaches a process cartridge in a direction orthogonal to the axial direction of the image carrier as the image forming apparatus. The process cartridge is mounted on the apparatus main body after being positioned by a positioning member attached to a side plate of the apparatus main body.

  However, in the image forming apparatus described in Patent Document 1, the position of the image carrier relative to the transfer roller, which is the counter-rotating member arranged to face the image carrier, due to an assembly error of the positioning member for positioning the process cartridge with respect to the side plate. There was a case where it shifted. Further, there is a possibility that a positional deviation may occur due to an assembly error of the positioning member with respect to the side plate with respect to the driving device that drives the image carrier attached to the apparatus main body. There is a possibility that the image quality is deteriorated due to the occurrence of such a displacement.

  In order to solve the above-described problems, the present invention has a rotator and is configured to be detachable in a direction perpendicular to the axial direction of the rotator, and the detachable unit is mounted on the apparatus main body. An image forming apparatus comprising: a driving device that drives the rotating body in a state; and an opposing rotating body unit having an opposing rotating body that faces the rotating body in a state where the detachable unit is attached to the apparatus main body. The detachable unit and the driving device are positioned on the same member of the counter rotating body unit.

  According to the present invention, it is possible to suppress a decrease in image quality.

1 is a schematic configuration diagram illustrating a printer according to an embodiment. The perspective view of a transfer unit. FIG. 3 is a perspective view showing a relationship between a transfer unit and a process cartridge when the process cartridge is mounted on the apparatus main body. The perspective view which shows the process cartridge and the transfer unit which were positioned by the transfer unit. The perspective view of the drive device which drives a photoconductor. The perspective view which shows a drive device and a part of process cartridge. FIG. 2 is a schematic plan view showing a photoconductor, a driving device, and a side wall portion of a transfer frame. The cross-sectional perspective view cut in the position of AA of FIG. Sectional drawing cut in the position of AA of FIG.

Hereinafter, as an image forming apparatus to which the present invention is applied, an electrophotographic printer (hereinafter simply referred to as a printer) that forms an image by an electrophotographic method will be described.
FIG. 1 is a schematic configuration diagram illustrating a printer according to an embodiment.
The printer shown in FIG. 1 is a monochrome printer. A process cartridge 1 as an attachment / detachment unit is detachably attached to the apparatus main body 100. The process cartridge 1 visualizes a latent image on the photoreceptor 2 as a photoreceptor 2 as an image carrier that carries an image on the surface, a charging roller 3 as a charging unit that charges the surface of the photoreceptor 2, and the like. A developing device 4 as a developing unit and a cleaning blade 5 as a cleaning unit for cleaning the surface of the photoreceptor 2 are provided. Further, an LED head array 6 is disposed around the photosensitive member 2 as exposure means for exposing the surface.

  The process cartridge 1 is detachably provided with a toner cartridge 7 as a developer container. The toner cartridge 7 has a developer accommodating portion 8 that accommodates toner as a developer to be replenished to the developing device 4 in the container main body 22. Furthermore, the toner cartridge 7 of this embodiment also has a developer recovery unit 9 that recovers the toner (waste toner) removed by the cleaning blade 5.

  The printer also includes a transfer unit 10 that transfers an image onto a sheet as a transfer body, a paper feeding device 11 that supplies the paper, a fixing device 12 that fixes the image transferred onto the paper, and discharges the paper to the outside. And a paper discharge device 13 for performing the operation.

  The transfer unit 10 includes a transfer roller 14 as a transfer member that is rotatably supported by the transfer frame 30. The transfer roller 14 is in contact with the photosensitive member 2 with the process cartridge 1 mounted on the apparatus main body 100, and a transfer nip is formed at the contact portion between the two. Further, the transfer roller 14 is connected to a power source, and is applied with a predetermined DC voltage (DC) and / or AC voltage (AC).

  The paper feed device 11 includes a paper feed cassette 15 that contains paper P and a paper feed roller 16 that feeds the paper P contained in the paper feed cassette 15. In addition, a pair of registration rollers 17 are provided on the downstream side of the paper feeding direction with respect to the paper feeding roller 16 as timing rollers for feeding the paper to the secondary transfer nip by measuring the feeding timing. The paper P includes cardboard, 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 other than paper.

  The fixing device 12 includes a fixing roller 18 as a fixing member and a pressure roller 19 as a pressure member. The fixing roller 18 is heated by an infrared heater 23 installed inside the fixing roller. The pressure roller 19 is pressed toward the fixing roller 18 and comes into contact with the fixing roller 18, and a fixing nip is formed at the contact portion.

  The paper discharge device 13 includes a pair of paper discharge rollers 20. The paper discharged out of the apparatus by the paper discharge roller 20 is stacked on a paper discharge tray 21 formed by denting the upper surface of the apparatus main body 100.

  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 member 2 of the process cartridge 1 is driven to rotate clockwise in FIG. 1, and the surface of the photosensitive member 2 is uniformly charged to a predetermined polarity by the charging roller 3. Based on image information input from an external device, light is irradiated from the LED head array 6 to the charging surface of the photoreceptor 2, and an electrostatic latent image is formed on the surface of the photoreceptor 2.

  The toner is supplied by the developing device 4 to the electrostatic latent image formed on the photoreceptor 2 in this manner, whereby the electrostatic latent image is visualized (visualized) as a toner image.

  When the image forming operation is started, the transfer roller 14 is driven to rotate, and a predetermined DC voltage (DC) and / or AC voltage (AC) is applied to the transfer roller 14, thereby A transfer electric field is formed between the photosensitive member 2 and the photosensitive member 2.

  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 cassette 15. The fed paper P is temporarily stopped by the registration roller 17.

  Thereafter, rotation of the registration roller 17 is started at a predetermined timing, and the paper P is conveyed to the transfer nip in accordance with the timing at which the toner image on the photoconductor reaches the transfer nip. Then, the toner image on the photosensitive member 2 is collectively transferred onto the paper P as a transfer member by the transfer electric field. Residual toner on the photoconductor that could not be transferred onto the paper P is removed by the cleaning blade 5, and the removed toner is conveyed to the developer collecting unit 9 and collected.

  Thereafter, the paper P on which the toner image is transferred is conveyed to the fixing device 12, and the toner image on the paper P is fixed on the paper P in the fixing device 12. Then, the paper P is discharged out of the apparatus by the pair of paper discharge rollers 20 and stocked on the paper discharge tray 21.

  An opening / closing cover 37 that can be opened and closed in the direction of the arrow in the drawing is provided on the side surface (right side surface in the drawing) of the apparatus main body 100. The LED head array 6 is connected to the opening / closing cover 37 by a link mechanism or the like, and the LED head 6 moves to a retracted position that does not obstruct the attachment / detachment of the process cartridge 1 in accordance with the opening operation of the opening / closing cover 37. It has become. Thus, by opening the opening / closing cover 37, the process cartridge 1 is taken out from the apparatus main body through the opened opening.

FIG. 2 is a perspective view of the transfer unit 10.
As shown in FIG. 2, the transfer unit 10 includes a transfer frame 30 that rotatably supports the transfer roller 14. The transfer frame 30 has a conveyance guide 39 that guides the paper P that has passed through the transfer nip. Further, process positioning portions 31 and 32 for positioning the process cartridge 1 are provided at both axial ends of the transfer frame 30. The process positioning parts 31 and 32 consist of a pair of inclined surfaces provided so as to face each other. Of the pair of inclined surfaces, the lower inclined surfaces 31b and 32b in the drawing are inclined surfaces that are positioned upward as they go downstream in the sheet conveying direction. In addition, the upper inclined surfaces 31a and 32a in the drawing are inclined surfaces that are positioned upward as they go downstream in the sheet conveyance direction.

  Fixing positioning recesses 33 and 34 are provided on both sides in the axial direction of the downstream end of the transfer frame 30 in the sheet conveyance direction, and are recessed on the upstream side in the sheet conveyance direction for positioning the fixing device 12. On both sides in the axial direction of the upstream end of the frame of the fixing device 12 in the sheet conveyance direction, convex fixing positioning protrusions protruding upstream in the sheet conveyance direction are provided. The fixing device 12 is attached to the apparatus main body from the downstream side to the upstream side in the sheet conveyance direction, and the positioning convex portions are fitted into the fixing positioning concave portions 33 and 34 of the transfer frame 30 attached to the apparatus main body. The fixing device 12 is positioned on the apparatus main body.

  In addition, a pair of transfer positioning portions 35 and 36 provided at predetermined intervals in the sheet conveyance direction are provided on the side wall portions 38 orthogonal to the axial direction at both ends of the transfer frame 30 in the axial direction. Concave drive positioning recesses 35a and 36a for positioning a driving device 40 (see FIG. 5), which will be described later, for driving the photoreceptor 2 are provided at the tops of the transfer positioning portions 35 and 36. The side wall portion 38 is formed with a plurality of screw holes 38a, 38b, and 38c having screw grooves formed on the inner peripheral surface. The transfer unit 10 is screwed to the side plate of the apparatus main body by screwing screws into these screw holes.

FIG. 3 is a perspective view showing the relationship between the transfer unit 10 and the process cartridge 1 when the process cartridge 1 is mounted on the apparatus main body. FIG. 4 is a view showing the process cartridge 1 and the transfer unit 10 positioned on the transfer unit 10. FIG.
As shown in FIG. 3, the process cartridge 1 moves in a direction orthogonal to the axial direction as shown by an arrow A in the drawing, and is attached to the apparatus main body. Arc-shaped positioning portions 1a are provided at both axial ends on the downstream side of the process cartridge 1 in the mounting direction. As shown in FIG. 4, when the process cartridge 1 is mounted on the apparatus main body, the arcuate positioning portion 1 a on the front side in the drawing is a pair of inclined surfaces 31 a and 31 b that form the process positioning portion 31 of the transfer frame 30. Abut. Further, the positioning portion 1a on the back side in the drawing contacts a pair of inclined surfaces 32a and 32b of the process positioning portion 32 of the transfer frame 30 shown in FIG. As a result, the process cartridge 1 is positioned on the transfer unit 10.

  As described above, when the process cartridge 1 is positioned on the transfer unit 10, it is possible to suppress the positional deviation of the photoreceptor 2 with respect to the transfer roller 14 held by the transfer unit 10. Thereby, the transfer roller 14 can be brought into contact with the photosensitive member 2 with a predetermined contact pressure, the transfer nip width can be set to a specified nip width, and good transferability can be obtained.

  The transfer frame 30 may be made of metal or resin. By configuring the transfer frame 30 with metal, the rigidity of the transfer frame 30 can be increased, and deformation such as twisting of the transfer frame 30 can be suppressed. Thereby, it can suppress that the transfer roller 14 supported by the transfer frame 30 inclines with respect to an axial direction. On the other hand, by forming the transfer frame 30 from resin, the transfer frame 30 can be manufactured by injection molding, and the transfer frame 30 can be formed at low cost. Thereby, the cost increase of an apparatus can be suppressed.

FIG. 5 is a perspective view of the driving device 40 that drives the photosensitive member 2.
As shown in FIG. 5, the drive device 40 includes a drive motor 46, an internal gear 47 that meshes with the motor gear of the drive motor 46, a photoconductor gear 45 that meshes with an external tooth portion provided on the outer periphery of the internal gear 47, and the like. . The drive motor 46, the internal gear 47, and the photoconductor gear 45 are held by the bracket 44. A joint member 48 that engages with the photoconductor gear 45 and is movable in the axial direction is provided at the rotation center of the photoconductor gear 45. Further, a release mechanism 43 for releasing the driving connection with the photosensitive member 2 by moving the joint member 48 in the axial direction is provided. The release mechanism 43 is connected to the opening / closing cover 37 shown in FIG. 1 through a link mechanism, for example, and is configured to move the joint member 48 in the axial direction in conjunction with opening / closing of the opening / closing cover 37. ing.

  The bracket 44 is provided with two positioning protrusions 42 and 43 that extend in the axial direction and are positioned on the transfer frame 30 of the transfer unit 10. Drive positioning convex portions 41 a and 42 a having a diameter smaller than that of the positioning projection portions 42 and 43 are formed at the tips of the positioning projection portions 42 and 43. Also, the bracket 44 is provided with a plurality of screw through holes 44a, 44b, 44c through which screws for screwing to the side plate 100a (see FIG. 7) of the apparatus main body pass.

FIG. 6 is a perspective view showing the driving device 40 and a part of the process cartridge 1.
As shown in FIG. 6, when the process cartridge 1 is taken out from the apparatus main body, the joint member 48 is moved to the photoconductor gear 45 side by the release mechanism 43, and the driven side joint portion 2 a provided on the photoconductor 2. The drive connection of is released. Thereby, the process cartridge 1 can be attached and detached in a direction orthogonal to the axial direction. When the process cartridge 1 is mounted on the apparatus main body, the joint member 48 is moved in the direction of the arrow in the drawing by the release mechanism 43, and the tip end portion of the joint member 48 is inserted into the driven side joint portion 2a. As a result, the joint member 48 is engaged with and driven by the driven joint portion 2a, and the driving force of the drive motor 46 is transmitted to the photosensitive member 2 so that the photosensitive member 2 can be driven to rotate.

FIG. 7 is a schematic plan view showing the photosensitive member 2, the driving device 40, and the side wall portion 38 of the transfer frame 30, and FIG. 8 is a cross-sectional perspective view taken along the line AA in FIG. FIG. 9 is a cross-sectional view taken along the line AA.
As shown in FIGS. 7 to 9, the transfer positioning portions 35 and 36 provided on the side wall portion 38 of the transfer frame 30 are fitted into the transfer positioning holes 101 and 102 provided on the side plate 100 a of the apparatus main body, thereby transferring the transfer. The unit 10 is positioned on the apparatus main body. The positioned transfer unit 10 is screwed to the side plate 100a.

  Further, driving positioning convex portions 41a and 42a provided at the tips of the positioning projections 42 and 43 of the driving device 40 are fitted into driving positioning concave portions 35a and 36a of the transfer unit 10 that are positioned and fixed to the side plate 100a. 40 is positioned on the transfer unit 10. As shown in FIG. 8, the driving device 40 positioned on the transfer unit 10 is screwed to the side plate 100 a with screws 140.

  In the present embodiment, the process cartridge 1 is detachable in a direction orthogonal to the axial direction, and the process cartridge 1 moves in a direction parallel to the side plate 100a of the apparatus main body. For example, in a configuration in which the process cartridge is attached and detached in a direction perpendicular to the side plate 100a, as with the transfer unit, the process cartridge is provided with a positioning projection, the side plate is provided with a positioning hole, and the process cartridge positioning projection is used as the side plate positioning hole. By fitting, the process cartridge can be positioned on the side plate. Therefore, if the drive device is positioned on the side plate, the process cartridge, the transfer unit, and the drive device can all be positioned on the same member. In this way, by positioning the process cartridge, the transfer unit, and the driving device on the side plate that is the same member, it is possible to suppress the accumulation of manufacturing errors and the accumulation of assembly errors. Thereby, the process cartridge can be satisfactorily positioned with respect to the driving device and the transfer unit.

  However, in a configuration in which the process cartridge 1 is attached and detached in a direction parallel to the side plate 100a, a configuration in which the process cartridge is positioned on the side plate by fitting the positioning protrusion of the process cartridge into the positioning hole of the side plate cannot be employed. This is because, when such a configuration is adopted, the positioning protrusion of the process cartridge is caught by the side plate, and the process cartridge 1 cannot be attached to or detached from the apparatus main body. For this reason, in this embodiment, the process positioning units 31 and 32 for positioning the process cartridge 1 are provided in the transfer unit 10 disposed on the inner side of the apparatus than the side plate so that the process cartridge is positioned on the transfer unit 10. Thereby, the process cartridge 1 can be attached and detached in a direction parallel to the side plate 100a.

  Here, when the driving device 40 is positioned on the side plate 100a of the apparatus main body to which the driving device 40, the transfer unit 10 and the like are attached, a shift between the rotation axis center of the joint member 48 and the rotation axis center of the photosensitive member 2 (hereinafter referred to as the rotation axis center). , Referred to as an axial misalignment) may increase. Specifically, the accumulation of manufacturing errors of members increases, and the axial misalignment between the joint member 48 and the photoreceptor 2 may increase. More specifically, when the driving device 40 is positioned on the side plate 100a, a manufacturing error of the bracket 44 of the driving device 40, a manufacturing error of the transfer frame of the transfer unit, a manufacturing error of the frame of the process cartridge 1, and the side plate 100a The accumulation of manufacturing errors affects the misalignment between the joint member 48 and the photosensitive member. On the other hand, when the drive device 40 is positioned on the transfer frame 30 of the transfer unit 10 that is a member on which the process cartridge 1 is positioned as in the present embodiment, the influence of the axial misalignment between the joint member 48 and the photoreceptor 2 is reduced. The manufacturing error of the three members, that is, the manufacturing error of the bracket 44, the manufacturing error of the transfer frame 30, and the manufacturing error of the frame of the process cartridge can be accumulated, and the influence of the manufacturing error of the side plate can be eliminated. Thereby, it is possible to suppress the axial misalignment between the joint member 48 and the photosensitive member 2 as compared with the case where the driving device is positioned on the side plate. Thereby, rotation unevenness of the photosensitive member 2 can be suppressed, occurrence of abnormal images such as banding can be suppressed, and deterioration of image quality can be suppressed.

  In the present embodiment, the transfer frame 30 on which the driving device 40 and the process cartridge are positioned is provided with transfer positioning portions 35 and 36 that are positioned on the side plate 100a of the apparatus main body. Thereby, the position shift of the drive device 40 or the process cartridge 1 with respect to the side plate 100a can be suppressed, and the position shift between the other members positioned on the side plate 100a can be suppressed.

What was demonstrated above is an example, and there exists an effect peculiar for every following aspect.
(Aspect 1)
A detachable unit such as a process cartridge 1 having a rotator such as the photosensitive member 2 and configured to be detachable in a direction perpendicular to the axial direction of the rotator, and the detachable unit mounted on the apparatus main body. Image formation comprising: a driving device 40 for driving the rotating body; and an opposing rotating body unit having an opposing rotating body such as a transfer roller 14 facing the rotating body in a state where the detachable unit is mounted on the apparatus main body. In the apparatus, the detachable unit and the driving device are positioned on the same member of the counter rotating body unit.
According to the first aspect, the detachable unit such as the process cartridge 1 is directly positioned on the counter rotating body unit such as the transfer unit 10, so that the rotating body such as the photosensitive member 2 is displaced from the counter rotating body such as the transfer roller 14. Can be suppressed. In addition, by positioning the driving device 40 on a member such as the transfer frame 30 on which the mounting / demounting unit of the counter rotating body unit is positioned, manufacturing is performed as compared with the case where the driving device 40 and the mounting / demounting unit are positioned on different members. Accumulation of errors and assembly errors can be suppressed. Thereby, compared with the case where the drive device 40 and the attachment / detachment unit are respectively positioned on different members, the displacement of the drive device with respect to the attachment / detachment unit can be suppressed. Therefore, it is possible to suppress a decrease in image quality due to a positional shift.

(Aspect 2)
In the first aspect, the rotating body is an image carrier such as the photoreceptor 2, and the counter rotating body is the transfer roller 14.
According to this, as described in the embodiment, the positional deviation of the transfer roller 14 with respect to the image carrier such as the photosensitive member 2 can be suppressed, and a good image on the image carrier is transferred to a transfer member such as paper. can do.

(Aspect 3)
In the first or second aspect, the opposing rotating body unit such as the transfer unit 10 includes positioning portions such as transfer positioning portions 35 and 36 for positioning with respect to the apparatus main body, and the drive device 40 and the detachable unit such as the process cartridge 1 Is positioned on a member having a positioning portion such as the transfer frame 30 of the counter rotating body unit.
According to this, as described in the embodiment, the detachable unit such as the process cartridge 1 and the driving device 40 can be positioned at a specified position of the apparatus main body, and other apparatuses and units assembled in the apparatus main body. Can be suppressed.

(Aspect 4)
In the aspect 3, the member having the positioning portion such as the transfer frame 30 of the counter rotating body unit such as the transfer unit 10 is a metal.
According to this, as described in the embodiment, the rigidity of the member having the positioning portion such as the transfer frame 30 can be increased as compared with the case where the resin is used. Thereby, position shift of attachment-detachment units, such as the process cartridge 1, by the deformation | transformation of the member which has a positioning part can be suppressed.

(Aspect 5)
In the aspect 3, the member having the positioning portion such as the transfer frame 30 of the counter rotating body unit such as the transfer unit is a resin.
According to this, as described in the embodiment, the member having the positioning portion such as the transfer frame 30 can be formed by injection molding, and the member having the positioning portion can be manufactured at a low cost.

DESCRIPTION OF SYMBOLS 1 Process cartridge 1a Positioning part 2 Photoconductor 2a Drive side joint part 10 Transfer unit 12 Fixing device 14 Transfer roller 30 Transfer frame 31, 32 Process positioning part 33, 34 Fixing positioning recessed part 35, 36 Transfer positioning part 35a, 36a Driving positioning recessed part 37 Opening / closing cover 38 Side wall portion 40 Drive devices 41a, 42a Drive positioning convex portions 42, 43 Positioning projection 43 Release mechanism 44 Bracket 45 Photoconductor gear 46 Drive motor 47 Internal gear 48 Joint member 100 Device main body 100a Side plate 101, 102 Transfer Positioning hole

Japanese Patent No. 5354371

Claims (5)

A detachable unit having a rotator and configured to be detachable in a direction perpendicular to the axial direction of the rotator;
A driving device for driving the rotating body in a state where the detachable unit is mounted on the apparatus main body;
In an image forming apparatus comprising: an opposing rotating body unit having an opposing rotating body facing the rotating body in a state where the detachable unit is mounted on the apparatus main body.
An image forming apparatus, wherein the detachable unit and the driving device are positioned on the same member of the counter rotating body unit. The image forming apparatus according to claim 1.
An image forming apparatus, wherein the rotating body is an image carrier, and the counter rotating body is a transfer roller. The image forming apparatus according to claim 1, wherein
The counter rotating body unit includes a positioning portion for positioning with respect to the apparatus main body,
An image forming apparatus, wherein the driving device and the detachable unit are positioned on a member having the positioning portion of the counter rotating body unit. The image forming apparatus according to claim 3.
The image forming apparatus, wherein the member having the positioning portion of the counter rotating body unit is a metal. The image forming apparatus according to claim 3.
The image forming apparatus, wherein the member having the positioning portion of the counter rotating body unit is a resin.

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