Image forming apparatus and adjustment method

Abstract

To make uniform an interval between a photoreceptor drum and a developing roller in an axial direction.SOLUTION: An image forming apparatus comprises: a photoreceptor drum 11 that holds a latent image; a photoreceptor housing 21 that supports the photoreceptor drum 11; a developing roller that holds developer; a developing housing 31 that supports the developing roller to bring an outer peripheral surface of the developing roller opposite to an outer peripheral surface of the photoreceptor drum 11, and swings to cause the developing roller to get close to or away from the photoreceptor drum 11; a first contact member 41 that is provided on both ends of the photoreceptor housing 21 in an axial direction of the photoreceptor drum 11; and a second contact member 42 that is provided on both ends in the axial direction of the developing housing 31 and brought into contact with the first contact member 41 by a force pressing the developing housing 31 toward the photoreceptor housing 21. The position of at least one of the first contact member 41 and the second contact member 42 can be adjusted in a direction in which the first contact member 41 and the second contact member 42 are caused to get close to or away from each other.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus and an adjustment method. [Background technology]

[0002] In electrophotographic development units, gap restriction members with a diameter slightly larger than that of the developing roller are typically provided at both axial ends of the developing roller. These gap restriction members are brought into contact with the photosensitive drum to provide a predetermined gap between the outer circumferential surfaces of the developing roller and the photosensitive drum. However, this configuration can result in gap errors due to the cumulative effect of tolerances between individual components. Furthermore, this can cause uneven rotation between the developing roller and the photosensitive drum, potentially resulting in fluctuations in image quality.

[0003] Therefore, technologies for adjusting the gap between the developing roller and the photosensitive drum have been studied. For example, Patent Document 1 describes an electrophotographic device including an axis-to-axis distance adjusting unit that adjusts the axis-to-axis distance so that the developer carrier is positioned at an adjusted position displaced relative to the photosensitive drum in the contact / separation direction, a locking unit that locks the adjusted position of the developer carrier in the contact / separation direction at multiple locations, and a fixing unit that fixes the adjusted position adjusted by the axis-to-axis distance adjusting unit. The axis-to-axis distance adjusting unit includes an eccentric cam whose rotation axis is displaced relative to the rotation axis of the developer carrier, and a positioning unit provided on the eccentric cam for positioning the developer carrier. The locking unit includes an engagement unit provided on the eccentric cam with multiple concave and convex portions along the rotation direction around the rotation axis of the eccentric cam, and a locking unit with a locking claw that locks the concave and convex portions. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-171068 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the configuration described in Patent Document 1, the eccentric cam is provided only at one end in the axial direction, making it difficult to maintain a uniform distance between the photosensitive drum and the developing roller in the axial direction. Also, because the end of the shaft of the developing roller is fitted into a recess in the eccentric cam, vibrations caused by the rotation of the developing roller are transmitted to the photosensitive drum via the eccentric cam, which may cause fluctuations in image quality.

[0006] SUMMARY OF THE INVENTION In consideration of the above circumstances, an object of the present invention is to provide an image forming apparatus and an adjustment direction that can make the gap between the photosensitive drum and the developing roller uniform in the axial direction. [Means for solving the problem]

[0007] In order to solve the above problem, the image forming apparatus of the present invention comprises a photosensitive drum that holds a latent image, a photosensitive housing that supports the photosensitive drum, a developing roller that holds developer, a developing housing that supports the developing roller so that the outer surface of the developing roller faces the outer surface of the photosensitive drum and swings to move the developing roller closer to and away from the photosensitive drum, first contact members provided at both ends of the photosensitive housing in the axial direction of the photosensitive drum, and second contact members provided at both ends of the developing housing in the axial direction and that contact the first contact member by a force that presses the developing housing toward the photosensitive housing, and is characterized in that at least one of the first contact member and the second contact member is position adjustable in a direction that moves the first contact member and the second contact member closer to and away from each other.

[0008] The first contact member may not contact the shaft of the photosensitive drum, and the second contact member may not contact the shaft of the developing roller.

[0009] The positions of the first contact member and the second contact member may be adjustable on a straight line intersecting an axis of the photosensitive drum and an axis of the developing roller.

[0010] Both ends of the photosensitive drum shaft protrude from the photosensitive housing, and the first contact member has a plurality of first elongated hole portions whose longitudinal direction is the direction of a line intersecting the axis of the photosensitive drum and the axis of the developing roller, and a first opening whose diameter is larger than both ends of the photosensitive drum shaft, and the first contact member is fixed to the photosensitive housing by screws via the plurality of first elongated hole portions, and its position can be adjusted along the longitudinal direction of the plurality of first elongated hole portions, and both ends of the photosensitive drum shaft are inserted into the first openings and are configured not to come into contact with the first opening regardless of the position of the first contact member.

[0011] Both ends of the shaft of the developing roller protrude from the developing housing, and the second contact member has a plurality of second oblong hole portions whose longitudinal direction is the direction of a line intersecting the axis of the photosensitive drum and the axis of the developing roller, and a second opening whose diameter is larger than both ends of the shaft of the developing roller, and the second contact member is fixed to the developing housing by screws via the plurality of second oblong hole portions, and its position can be adjusted along the longitudinal direction of the plurality of second oblong hole portions, and both ends of the shaft of the photosensitive drum are inserted into the second openings and are configured not to come into contact with the second opening regardless of the position of the second contact member.

[0012] The positions of the first contact member and the second contact member may both be adjustable in a direction in which the first contact member and the second contact member approach or move away from each other.

[0013] In addition, the adjustment method of the present invention is characterized by comprising the steps of: using a master development unit having the developing roller, the development housing, and the second contact member whose position has been adjusted in advance, adjusting the position of the first contact member so that the photosensitive drum and the developing roller are spaced a predetermined distance apart; and using a master photosensitive unit having the photosensitive drum, the photosensitive housing, and the first contact member whose position has been adjusted in advance, adjusting the position of the second contact member so that the photosensitive drum and the developing roller are spaced a predetermined distance apart.

[0014] The adjustment method may include a process of temporarily fastening the first contact member with the screw and then welding it to the photosensitive body housing, and a process of temporarily fastening the second contact member with the screw and then welding it to the developing housing. [Effects of the Invention]

[0015] According to the present invention, the distance between the photosensitive drum and the developing roller can be made uniform in the axial direction. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a front view schematically illustrating an internal configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view of a photosensitive unit according to an embodiment of the present invention. [Figure 3] FIG. 2 is a perspective view of a developing unit according to an embodiment of the present invention. [Figure 4] FIG. 2 is a front view schematically illustrating the internal configuration of a photosensitive unit and a developing unit according to an embodiment of the present invention. [Figure 5] FIG. 2 is a front view schematically illustrating the internal configuration of a photosensitive unit and a developing unit according to an embodiment of the present invention. [Figure 6] FIG. 2 is a perspective view of a first contact member according to one embodiment of the present invention. [Figure 7] FIG. 2 is a perspective view of a first contact member according to one embodiment of the present invention. [Figure 8] FIG. 4 is a perspective view of a second contact member according to one embodiment of the present invention. [Figure 9] FIG. 4 is a perspective view of a second contact member according to one embodiment of the present invention. [Figure 10] FIG. 2 is a perspective view of the front portion of a photosensitive unit and a developing unit attached to a main body housing according to an embodiment of the present invention. [Figure 11] FIG. 2 is a perspective view showing a state in which a first contact member and a second contact member are attached to the front side of a photosensitive unit and a developing unit according to one embodiment of the present invention. [Figure 12] FIG. 2 is a perspective view of a rear portion of a photosensitive unit and a developing unit attached to a main body housing according to an embodiment of the present invention. [Figure 13] FIG. 2 is a perspective view showing a state in which a first contact member and a second contact member are attached to the rear side of a photosensitive unit and a developing unit according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] An image forming apparatus 100 according to one embodiment of the present invention will be described below with reference to the drawings.

[0018] First, the overall configuration of image forming apparatus 100 will be described. Fig. 1 is a front view that schematically shows the internal configuration of image forming apparatus 100. In the following description, the front side of the paper in Fig. 1 is the front side (front side) of image forming apparatus 100, and left and right directions will be described based on the direction when image forming apparatus 100 is viewed from the front. In each figure, U, Lo, L, R, Fr, and Rr represent up, down, left, right, front, and rear, respectively.

[0019] The image forming apparatus 100 includes a printer 1, a scanner 110, and a document feeder 120. The scanner 110 is provided above the printer 1, and the document feeder 120 is provided above the scanner 110. The document feeder 120 transports a document via the reading position of the scanner 110. The scanner 110 is a flatbed image scanner that reads a document and generates image data. The printer 1 forms an image on a sheet S based on the image data.

[0020] The printer 1 includes a rectangular parallelepiped main body housing 3. At the bottom inside the main body housing 3 are a paper feed cassette 4 that stores sheets S, and a paper feed roller 5 that feeds sheets S from the paper feed cassette 4 to the right. Above the paper feed cassette 4 is an imaging device 6 that forms a toner image using an electrophotographic method, and above and to the right of the imaging device 6 is a fixing device 7 that fixes the toner image to the sheet S. Above the fixing device 7 are a paper discharge roller 8 that discharges the sheet S with the fixed toner image, and a paper discharge tray 9 on which the discharged sheets S are stacked.

[0021] Inside the main body housing 3, there is provided a conveyance path 10 that runs from the paper feed roller 5 through the image forming device 6 and the fixing device 7 to the paper discharge roller 8. The conveyance path 10 is formed using plate-like members that face each other with a gap therebetween to allow the sheet S to pass through, and conveyance rollers 17 that sandwich and convey the sheet S are provided at multiple locations in the conveyance direction Y. A registration roller 18 is provided upstream of the image forming device 6 in the conveyance direction Y. To the right of the fixing device 7, there is provided a reversing conveyance path 10R that branches off from the conveyance path 10 downstream of the fixing device 7 in the conveyance direction Y and merges with the conveyance path 10 upstream of the registration roller 18 in the conveyance direction Y.

[0022] The image forming device 6 includes a photosensitive drum 11 whose potential changes when irradiated with light, a charging device 12 that charges the photosensitive drum 11, an exposure device 13 that emits laser light according to image data, a developing unit 14 that supplies toner to the photosensitive drum 11, an intermediate transfer unit 15 that transfers the toner image from the photosensitive drum 11 to a sheet S, and a cleaning device 16 that removes toner remaining on the photosensitive drum 11. The intermediate transfer unit 15 includes an endless intermediate transfer belt 15B wrapped around a drive roller 15D and a driven roller 15N, a primary transfer roller 151 that faces the inner surface of the intermediate transfer belt 15B at a position corresponding to the photosensitive drum 11 and generates a primary transfer bias, and a secondary transfer roller 152 that faces the outer surface of the intermediate transfer belt 15B at a position corresponding to the drive roller 15D and generates a secondary transfer bias. A toner container 20 that supplies toner to the developing unit 14 is connected to the developing unit 14.

[0023] The image forming device 6 includes four sets of photosensitive drums 11, charging devices 12, exposure devices 13, developing units 14, primary transfer rollers 151, cleaning devices 16, and toner containers 20, and forms a color image by superimposing four color toner images on the intermediate transfer belt 15B. Note that the present invention may also be applied to an image forming device 100 that forms a color image using toners of three or less colors or five or more colors.

[0024] The control unit 2 includes a calculation unit and a storage unit. The calculation unit is, for example, a CPU (Central Processing Unit). The storage unit includes storage media such as ROM (Read Only Memory), RAM (Random Access Memory), and EEPROM (Electrically Erasable Programmable Read Only Memory). The calculation unit performs various processes by reading and executing control programs stored in the storage unit. Note that the control unit 2 may be realized by only an integrated circuit without using software.

[0025] An operation unit 19 is provided on the front side of the scanner 110. The operation unit 19 includes a display panel, a touch panel superimposed on the display surface of the display panel, and a keypad adjacent to the display panel. The control unit 2 displays screens showing operation menus and statuses of the printer 1 and scanner 110 on the display panel, and controls each part of the printer 1 and scanner 110 in response to operations detected by the touch panel and keypad.

[0026] The basic image formation operation of the printer 1 is as follows: When a print job for single-sided printing is input to the printer 1 from the operation unit 19 or an external computer, the paper feed roller 5 feeds the sheet S from the paper feed cassette 4 to the transport path 10. The registration rollers 18, which have stopped rotating, correct any skew in the sheet S, and then feed the sheet S to the image creating device 6 at a predetermined timing. In the image creating device 6, the charging device 12 charges the photosensitive drum 11 to a predetermined potential, the exposure device 13 writes a latent image on the photosensitive drum 11, the developing unit 14 develops the latent image with toner supplied from the toner container 20 to form a toner image, the primary transfer roller 15A transfers the toner image to the intermediate transfer belt 15B, and the secondary transfer roller 15C transfers the toner image to the sheet S. Next, the fixing device 7 melts the toner image while nipping and transporting the sheet S, thereby fixing the toner image to the sheet S, and the sheet ejection rollers 8 eject the sheet S to the sheet ejection tray 9. The cleaning device 16 removes toner remaining on the photosensitive drum 11. In the case of double-sided printing, the sheet S with a toner image fixed on its first surface is sent into the conveying path 10 via the reverse conveying path 10R, where the toner image is transferred to the second surface.

[0027] Next, the photosensitive unit 24 and the developing unit 14 will be described. Fig. 2 is a perspective view of the photosensitive unit 24. Fig. 3 is a perspective view of the developing unit 14. Figs. 4 and 5 are front views schematically showing the internal configurations of the photosensitive unit 24 and the developing unit 14.

[0028] [Photosensitive unit] The photosensitive unit 24 integrates the photosensitive drum 11, charging device 12, and cleaning device 16 housed in a photosensitive housing 21. The lower part of the photosensitive housing 21 is box-shaped with the longitudinal direction extending in the front-to-rear direction, and the charging device 12 is housed inside. A support frame 60 is provided in the main housing 3. The support frame 60 is provided with a photosensitive housing support portion 62 into which the lower part of the photosensitive housing 21 is fitted. The photosensitive drum 11 is provided above the charging device 12, and the cleaning device 16 is provided to the right of the photosensitive drum 11. A shaft 11S of the photosensitive drum 11 is supported by bearings (not shown) provided at both front and rear ends of the photosensitive housing 21 and protrudes from the outer surfaces of both front and rear ends of the photosensitive housing 21. A driven gear 11G is provided at the rear end of the shaft 11S of the photosensitive drum 11.

[0029] [Developing unit] The developing unit 14 includes two screws 33 that rotate around their axes to agitate the developer, a developing roller 32 that holds the developer above the screws 33, a developing housing 31 that houses the screws 33 and the developing roller 32 and has an opening 31A that exposes part of the outer circumferential surface of the developing roller 32, and a blade 34 that is disposed below the opening 31A and regulates the layer thickness of the developer held on the developing roller 32. The developing roller 32 and the screws 33 are both disposed with their axial direction aligned in the front-to-rear direction.

[0030] The developer is, for example, a two-component developer containing a magnetic carrier and non-magnetic toner. The two screws 33 are arranged parallel to each other, one on the left and one on the right, inside the developer housing 31, and transport the developer in opposite directions. A partition wall 31W is provided between the two screws 33. Gaps are provided between the front end of the partition wall 31W and the inner surface of the developer housing 31, and between the rear end of the partition wall 31W and the inner surface of the developer housing 31, and the developer circulates around the partition wall 31W through the gaps. The developer is stirred by the screw 33, causing the toner to become frictionally charged.

[0031] The developing roller 32 is disposed above and parallel to the right screw 33. The developing roller 32 includes a permanent magnet and a developing sleeve (not shown) made of a non-magnetic material that surrounds the permanent magnet. The shaft 32S of the developing roller 32 is supported by bearings (not shown) provided at both front and rear ends of the developing housing 31 and protrudes from the outer surfaces of both front and rear ends of the developing housing 31. A driven gear 32G is provided at the rear end of the shaft 32S of the developing roller 32. The opening 31A is formed on the right side of the upper part of the developing housing 31, and the outer surface of the developing roller 32 exposed through the opening 31A faces the outer surface of the photosensitive drum 11. The developer forms a magnetic brush layer on the surface of the developing roller 32. The tip of the blade 34 is disposed at a predetermined distance from the developing roller 32, and adjusts the magnetic brush layer thickness to a predetermined thickness.

[0032] The support frame 60 is provided with fulcrums 61 that support the lower part of the developing housing 31 at two points, front and rear, on the photosensitive unit 24 side. A fulcrum connection part 31P that is connected to the fulcrum 61 is provided at the bottom of the developing housing 31. The fulcrum 61 and the fulcrum connection part 31P function as a rotation fulcrum with the front-rear direction as the axial direction, and the developing housing 31 can swing around the fulcrum 61. To the left of the fulcrum 61, a biasing member 3 8 The biasing member 3 is provided. 8 is, for example, a compression coil spring inserted between the support frame 60 and the developing housing 31, and biases the developing housing 31 toward the photosensitive member housing 21.

[0033] figure 4、5 2 shows the state in which the developing housing 31 swings. 4 is the biasing member 3 8 This shows a state in which no force is acting to resist the biasing force of the developing roller 32, and the developing roller 32 is closest to the photosensitive drum 11, i.e., the developing roller 32 is in contact with the photosensitive drum 11. 5 is the biasing member 3 81 shows the state in which the developing housing 31 is pushed back in the counterclockwise direction against the biasing force of the developing roller 32, and the developing roller 32 is separated from the photosensitive drum 11.

[0034] Next, a configuration for adjusting the gap between the photosensitive drum 11 and the developing roller 32 will be described. Figures 6 and 7 are perspective views of the first contact member 41. Figures 8 and 9 are perspective views of the second contact member 42. Figure 10 is a perspective view of the front portions of the photosensitive unit 24 and developing unit 14 attached to the main body housing 3. Figure 11 is a perspective view showing the first contact member 41 and the second contact member 42 attached to the front sides of the photosensitive unit 24 and developing unit 14. Figure 12 is a perspective view of the rear portions of the photosensitive unit 24 and developing unit 14 attached to the main body housing 3. Figure 13 is a perspective view showing the first contact member 41 and the second contact member 42 attached to the rear sides of the photosensitive unit 24 and developing unit 14.

[0035] The image forming device 100 comprises a photosensitive drum 11 that holds a latent image, a photosensitive housing 21 that supports the photosensitive drum 11, a developing roller 32 that holds a developer, a developing housing 31 that supports the developing roller 32 so that the outer surface of the developing roller 32 faces the outer surface of the photosensitive drum 11 and swings to move the developing roller 32 closer to and away from the photosensitive drum 11, first contact members 41 provided at both ends of the photosensitive housing 21 in the axial direction of the photosensitive drum 11, and second contact members 42 provided at both ends of the developing housing 31 in the axial direction and that contact the first contact member 41 by a force that presses the developing housing 31 toward the photosensitive housing 21, and at least one of the first contact member 41 and the second contact member 42 is position adjustable in a direction that moves the first contact member 41 and the second contact member 42 closer to and away from each other.

[0036] In this embodiment, the force that presses the developing housing 31 toward the photosensitive member housing 21 is, for example, the force that presses the developing housing 31 toward the photosensitive member housing 21. 8 The elastic force generated by the biasing member 3 is used. 8Instead of this, an eccentric cam, a magnetic spring, or the like may be used, or a configuration may be used in which the developing housing 31 is pressed toward the photosensitive member housing 21 by gravity. Note that the photosensitive drum 11, the photosensitive member housing 21, the developing roller 32, and the developing housing 31 are as described above, so the following description will mainly focus on the first contact member 41 and the second contact member 42.

[0037] The first contact member 41 and the second contact member 42 are generally rectangular plate-shaped members whose longitudinal direction is the direction of a line intersecting the axis 11S of the photosensitive drum 11 and the axis 32S of the developing roller 32. In this embodiment, the axis 11S of the photosensitive drum 11 is positioned slightly higher than the axis 32S of the developing roller 32, so the line intersecting the axis 11S of the photosensitive drum 11 and the axis 32S of the developing roller 32 is inclined so that the photosensitive drum 11 side (right side) is higher. Therefore, the first contact member 41 and the second contact member 42 are also arranged at an inclination so that the right side of the horizontally long rectangle is higher. Hereinafter, the direction of the line intersecting the axis 11S of the photosensitive drum 11 and the axis 32S of the developing roller 32 is referred to as the adjustment direction A.

[0038] [First contact member] The left end of the first contact member 41 (see FIGS. 6 and 7) is provided with a first contact surface 41F, the central portion of which in the vertical direction bulges out to the left in a bow shape. To the right of the first contact surface 41F, there are provided, in order from left to right, a first opening 41A, a first jig insertion portion 41J, and a first elongated hole 41Ha. ​​A first elongated hole 41Hb is provided in the downwardly protruding portion between the first contact surface 41F and the first opening 41A. The first opening 41A is a generally circular hole that penetrates in the front-rear direction and has a larger diameter than the shaft 11S of the photosensitive drum 11. The first jig insertion portion 41J is a hole that penetrates in the front-rear direction. The first elongated hole portions 41Ha and 41Hb are elongated holes that penetrate in the front-rear direction and have the adjustment direction A as their longitudinal direction. In this embodiment, the first oblong hole portion 41Ha is larger than the first oblong hole portion 41Hb, but the first oblong hole portion 41Ha and the first oblong hole portion 41Hb may be of any size.

[0039] Both front and rear ends of the photosensitive drum housing 21 (see FIGS. 10 and 12) are provided with screw holes 26 corresponding to the first elongated hole portions 41Ha and 41Hb of the first contact member 41. Both ends of the shaft 11S of the photosensitive drum 11 are inserted into the first opening 41A (see FIGS. 11 and 13). The first contact member 41 is fixed to the photosensitive drum housing 21 by screws 41Sa and 41Sb through the first elongated hole portions 41Ha and 41Hb.

[0040] The first oblong hole 41Ha (see FIG. 7) has arc-shaped curved surfaces facing laterally and flat surfaces facing vertically. The flat surfaces are parallel to the adjustment direction A. The screw 41Sa (see FIGS. 11 and 13) has a cylindrical portion 41SaC (a portion without threads) between the head and the threaded portion (a portion with threads). In FIG. 7, the outline of the outer surface of the cylindrical portion 41SaC is indicated by a two-dot chain line. The diameter of the cylindrical portion 41SaC is equal to the distance between the upper and lower flat surfaces of the first oblong hole 41Ha. ​​FIG. 7 shows the cylindrical portion 41SaC positioned at the center of the first oblong hole 41Ha in the horizontal direction, with equal adjustment margins M (margins) provided on both sides along the adjustment direction A. In addition, a gap wider than the adjustment margin M is provided around the entire circumference between the first opening 41A and the shaft 11S of the photosensitive drum 11.

[0041] The first oblong hole portion 41Hb (see FIG. 7) similarly has arc-shaped curved surface portions facing laterally and flat surface portions facing vertically. The flat surface portions are parallel to the adjustment direction A. The screw 41Sb (see FIGS. 11 and 13) has a cylindrical portion 41SbC between the head and the threaded portion. In FIG. 7, the outline of the outer circumferential surface of the cylindrical portion 41SbC is indicated by a two-dot chain line. The diameter of the cylindrical portion 41SbC is smaller than the distance between the upper and lower flat surface portions of the first oblong hole portion 41Hb, and the upper flat surface portion is in contact with the cylindrical portion 41SbC. A gap having a width equal to or greater than the adjustment allowance M is provided between the cylindrical portion 41SbC and the left and right curved surface portions.

[0042] [Second contact member] The second contact member 42 has a basic shape generally common to that of the first contact member 41. The right end of the second contact member 42 (see FIGS. 8 and 9) is provided with a second contact surface 42F, the vertical center of which bulges outward in a bow-like shape. To the left of the second contact surface 42F, a second opening 42A, a second jig insertion portion 42J, and a second elongated hole 42Ha are provided, in this order from right to left. The distance between the second contact surface 42F and the second opening 42A is shorter than the distance between the first contact surface 41F and the first opening 41A. A second elongated hole 42Hb is provided in the downwardly protruding portion between the second contact surface 42F and the second opening 42A. The second opening 42A is a generally circular hole that penetrates in the front-rear direction and has a diameter larger than that of the shaft 32S of the developing roller 32. The second jig insertion portion 42J is a hole that penetrates in the front-rear direction. The second oblong hole portions 42Ha, 42Hb are oblong holes that penetrate in the front-rear direction and whose longitudinal direction is the adjustment direction A. In this embodiment, the second oblong hole portion 42Ha is larger than the second oblong hole portion 42Hb, but the second oblong hole portions 42Ha and 42Hb may be of any size.

[0043] Both front and rear ends of the developer housing 31 (see FIGS. 10 and 12) are provided with screw holes 36 that correspond to the second elongated hole portions 42Ha and 42Hb of the second contact member 42. Both ends of the shaft 32S of the developer roller 32 are inserted into the second opening 42A (see FIGS. 11 and 13). The second contact member 42 is fixed to the developer housing 31 by screws 42Sa and 42Sb via the second elongated hole portions 42Ha and 42Hb.

[0044] The second oblong hole 42Ha (see FIG. 8) has arc-shaped curved surfaces facing laterally and flat surfaces facing vertically. The flat surfaces are parallel to the adjustment direction A. The screw 42Sa (see FIGS. 11 and 13) has a cylindrical portion 42SaC between its head and threaded portion. The diameter of the cylindrical portion 42SaC is equal to the distance between the upper and lower flat surfaces of the second oblong hole 42Ha. FIG. 8 shows that the cylindrical portion 42SaC is positioned in the horizontal center of the second oblong hole 42Ha, and equal adjustment margins M (margins) are provided on both sides along the adjustment direction A. In addition, a gap wider than the adjustment margin M is provided around the entire circumference between the second opening 42A and the shaft 32S of the developing roller 32.

[0045] The second oblong hole portion 42Hb (see FIG. 8) similarly has arc-shaped curved surface portions facing left and right and flat surface portions facing up and down. The flat surface portions are parallel to the adjustment direction A. The screw 42Sb (see FIGS. 11 and 13) has a cylindrical portion 42SbC between the head and the threaded portion. The diameter of the cylindrical portion 42SbC is smaller than the distance between the upper and lower flat surface portions of the second oblong hole portion 42Hb, and the upper flat surface portion is in contact with the cylindrical portion 42SbC. A gap with a width equal to or greater than the adjustment allowance M is provided between the cylindrical portion 42SbC and the left and right curved surface portions.

[0046] The position of the first contact member 41 relative to the photosensitive member housing 21 is adjusted by loosely temporarily fastening the screws 41Sa and 41Sb and moving the first contact member 41 along the adjustment direction A. The position of the second contact member 42 relative to the developing housing 31 is adjusted by loosely temporarily fastening the screws 42Sa and 42Sb and moving the second contact member 42 along the adjustment direction A.

[0047] When adjusting the positions of the first contact member 41 and the second contact member 42, the first contact member 41 and the second contact member 42 may be manually moved left and right, but high-precision adjustment can be easily made by inserting a jig that can move a small distance, for example, into the first jig insertion portion 41J and the second jig insertion portion 42J.

[0048] The above configuration makes it possible to adjust the gap between the photosensitive drum 11 and the developing roller 32, but in actual adjustment, the position of the first contact member 41 (or the second contact member 42) is temporarily determined, and then the position of the second contact member 42 (or the first contact member 41) is adjusted so that the gap between the photosensitive drum 11 and the developing roller 32 is appropriate. However, because the photosensitive unit 24 and the developing unit 14 are made up of a large number of assembled parts, the accumulation of tolerances between the parts may mean that the adjustment after temporary determination does not result in an appropriate gap. In such cases, it is necessary to temporarily determine the gap again and make the adjustment.

[0049] To avoid such cumbersome work, it is desirable to store photosensitive unit 24 (master photosensitive unit) and developing unit 14 (master developing unit) in which the distance between photosensitive drum 11 and developing roller 32 has been adjusted with high accuracy in advance, and to perform adjustments based on these. That is, the adjustment method according to this embodiment includes the steps of: using a master developing unit having developing roller 32, developing housing 31, and second contact member 42 whose position has been adjusted in advance, adjusting the position of first contact member 41 so that photosensitive drum 11 and developing roller 32 are spaced a predetermined distance apart; and using a master photosensitive unit having photosensitive drum 11, photosensitive housing 21, and first contact member 41 whose position has been adjusted in advance, adjusting the position of second contact member 42 so that photosensitive drum 11 and developing roller 32 are spaced a predetermined distance apart. Either of these two steps may be performed first.

[0050] The image forming apparatus 100 according to the present embodiment described above comprises a photosensitive drum 11 that holds a latent image, a photosensitive housing 21 that supports the photosensitive drum 11, a developing roller 32 that holds a developer, a developing housing 31 that supports the developing roller 32 so that the outer peripheral surface of the developing roller 32 faces the outer peripheral surface of the photosensitive drum 11 and swings to move the developing roller 32 closer to and away from the photosensitive drum 11, first contact members 41 provided at both ends of the photosensitive housing 21 in the axial direction of the photosensitive drum 11, and second contact members 42 provided at both ends of the developing housing 31 in the axial direction and that contact the first contact member 41 by a force that presses the developing housing 31 toward the photosensitive housing 21, and at least one of the first contact member 41 and the second contact member 42 is adjustable in the direction of moving the first contact member 41 and the second contact member 42 closer to and away from each other. According to this configuration, the first contact member 41 and the second contact member 42 are provided at both ends in the axial direction, so that the distance between the photosensitive drum 11 and the developing roller 32 can be made uniform in the axial direction.

[0051] Furthermore, according to the image forming apparatus 100 of this embodiment, the first contact member 41 does not contact the shaft 11S of the photosensitive drum 11, and the second contact member 42 does not contact the shaft 32S of the developing roller 32, so degradation of image quality due to vibrations accompanying the rotation of the photosensitive drum 11 and the developing roller 32 can be suppressed.

[0052] Furthermore, according to the image forming apparatus 100 of this embodiment, the positions of the first contact member 41 and the second contact member 42 can be adjusted on a straight line that intersects with the axis 11S of the photosensitive drum 11 and the axis 32S of the developing roller 32. With this configuration, the amount of movement of the first contact member 41 and the second contact member 42 is equal to the amount of change in the gap between the photosensitive drum 11 and the developing roller 32, making it easy to adjust the gap.

[0053] Furthermore, according to the image forming apparatus 100 of this embodiment, both ends of the shaft 11S of the photosensitive drum 11 protrude from the photosensitive housing 21, and the first contact member 41 has a plurality of first oblong hole portions 41Ha, 41Hb whose longitudinal direction is the direction of a line intersecting the shaft 11S of the photosensitive drum 11 and the shaft 32S of the developing roller 32, and a first opening 41A whose diameter is larger than both ends of the shaft 11S of the photosensitive drum 11, and the first contact member 41 is fixed to the photosensitive housing 21 by screws 41Sa, 41Sb via the multiple first oblong hole portions 41Ha, 41Hb, and its position can be adjusted along the longitudinal direction of the multiple first oblong hole portions 41Ha, 41Hb, and both ends of the shaft 11S of the photosensitive drum 11 are inserted into the first opening 41A and do not come into contact with the first opening 41A regardless of the position of the first contact member 41, thereby suppressing degradation of image quality due to vibration.

[0054] Furthermore, according to the image forming apparatus 100 of this embodiment, both ends of the shaft 32S of the developing roller 32 protrude from the developing housing 31, and the second contact member 42 has a plurality of second oblong hole portions 42Ha, 42Hb whose longitudinal direction is the direction of a line intersecting the shaft 11S of the photosensitive drum 11 and the shaft 32S of the developing roller 32, and a second opening 42A whose diameter is larger than both ends of the shaft 32S of the developing roller 32, and the second contact member 42 is fixed to the developing housing 31 by screws 42Sa, 42Sb via the multiple second oblong hole portions 42Ha, 42Hb, and its position can be adjusted along the longitudinal direction of the multiple second oblong hole portions 42Ha, 42Hb, and both ends of the shaft 11S of the photosensitive drum 11 are inserted into the second opening 42A and do not come into contact with the second opening 42A regardless of the position of the second contact member 42, thereby suppressing degradation of image quality due to vibration.

[0055] Furthermore, according to the image forming apparatus 100 of this embodiment, the positions of both the first contact member 41 and the second contact member 42 can be adjusted in the direction of moving the first contact member 41 and the second contact member 42 closer to or further apart, thereby allowing for a greater adjustment range for the distance between the photosensitive drum 11 and the developing roller 32.

[0056] Furthermore, the adjustment method according to this embodiment includes a process of adjusting the position of the first contact member 41 using a master developing unit having a developing roller 32, a developing housing 31, and a second contact member 42 whose position has been adjusted in advance, so that the photosensitive drum 11 and the developing roller 32 are spaced a predetermined distance apart, and a process of adjusting the position of the second contact member 42 using a master photosensitive unit having a photosensitive drum 11, a photosensitive housing 21, and a first contact member 41 whose position has been adjusted in advance, so that the photosensitive drum 11 and the developing roller 32 are spaced a predetermined distance apart. Therefore, the spacing can be easily adjusted with high accuracy compared to when a master developing unit and a master photosensitive unit are not used.

[0057] The above embodiment may be modified as follows.

[0058] In the above embodiment, an example has been shown in which the first contact member 41 and the second contact member 42 are fixed with the screw 41Sa or the like, but after fixing with the screw 41Sa, the first contact member 41 may be welded to the photosensitive member housing 21 and the second contact member 42 to the developer housing 31. With this configuration, it is possible to prevent the positions of the first contact member 41 and the second contact member 42 from shifting.

[0059] In the above embodiment, an example has been shown in which the first contact member 41 and the second contact member 42 have partially different shapes, but the first contact member 41 and the second contact member 42 may have the same shape. This configuration can reduce costs.

[0060] In the above embodiment, an example has been shown in which the shaft 11S of the photosensitive drum 11 is inserted into the first opening 41A and the shaft 32S of the developing roller 32 is inserted into the second opening 42A, but the first contact member 41 may be provided above the shaft 11S of the photosensitive drum 11 and the second contact member 42 may be provided above the shaft 32S of the developing roller 32. Alternatively, the first contact member 41 may be provided below the shaft 11S of the photosensitive drum 11 and the second contact member 42 may be provided below the shaft 32S of the developing roller 32. Even with this configuration, effects similar to those of the above embodiment can be obtained.

[0061] The positions of the first elongated holes 41Ha, 41Hb and the first jig insertion portion 41J in the first contact member 41, and the positions of the second elongated holes 42Ha, 42Hb and the second jig insertion portion 42J in the second contact member 42 may be different from those in the above embodiment. Even with this configuration, the same effects as in the above embodiment can be obtained.

[0062] In the above embodiment, an example is shown in which the positions of both the first contact member 41 and the second contact member 42 can be adjusted, but it may also be possible to adjust the position of only one of the first contact member 41 and the second contact member 42. [Explanation of symbols]

[0063] 100 Image forming device 11 Photosensitive drum 11S axis 21 Photoconductor housing 31 Development housing 32 Developing roller 32S axis 41 first contact member 41A 1st opening 41Ha 1st oblong hole part 41Hb 1st oblong hole part 41Sa screw 41Sb screw 42 second contact member 42A 2nd opening 42Ha 2nd oblong hole part 42Hb Second oblong hole 42Sa screw 42Sb screw

Claims

1. a photosensitive drum that holds a latent image; a photosensitive drum housing supporting the photosensitive drum; a developing roller for holding a developer; a developing housing that supports the developing roller so that the outer peripheral surface of the developing roller faces the outer peripheral surface of the photosensitive drum and swings to move the developing roller toward and away from the photosensitive drum; first contact members provided at both ends of the photosensitive drum housing in the axial direction of the photosensitive drum; and second contact members provided at both ends of the developing housing in the axial direction, the second contact members contacting the first contact members by a force pressing the developing housing toward the photosensitive member housing, the positions of the first contact member and the second contact member are adjustable on a straight line intersecting an axis of the photosensitive drum and an axis of the developing roller, The second contact member is a plurality of second elongated hole portions whose longitudinal direction is a direction of a line intersecting the axis of the photosensitive drum and the axis of the developing roller; a second opening having a diameter larger than both ends of the shaft of the developing roller, the developing housing is fixed to the developing device by screws through the second elongated hole portions, and the position of the developing device is adjustable along the longitudinal direction of the second elongated hole portions; an image forming apparatus, characterized in that both ends of the shaft of the developing roller are inserted into the second opening and do not come into contact with the second opening regardless of the position of the second contact member;

2. the first contact member does not contact the shaft of the photosensitive drum, 2. The image forming apparatus according to claim 1, wherein the second contact member does not contact the shaft of the developing roller.

3. Both ends of the shaft of the photosensitive drum protrude from the photosensitive drum housing, The first contact member is a plurality of first elongated hole portions whose longitudinal direction is a direction of a line intersecting an axis of the photosensitive drum and an axis of the developing roller; a first opening having a diameter larger than both ends of the shaft of the photosensitive drum; the first contact member is fixed to the photosensitive body housing by screws through the plurality of first elongated hole portions, and the position of the first contact member is adjustable along a longitudinal direction of the plurality of first elongated hole portions; 3. The image forming apparatus according to claim 1, wherein both ends of the shaft of the photosensitive drum are inserted into the first opening and do not contact the first opening regardless of the position of the first contact member.

4. 4. The image forming apparatus according to claim 1, wherein the positions of the first contact member and the second contact member are both adjustable in a direction to move the first contact member and the second contact member closer to or further apart from each other.

5. a step of adjusting the position of the first contact member so that the photosensitive drum and the developing roller are spaced apart by a predetermined distance using a master developing unit having the developing roller, the developing housing, and the second contact member whose position has been adjusted in advance; and a step of adjusting the position of the second contact member so that the photosensitive drum and the developing roller are spaced apart by the predetermined distance using a master photosensitive unit having the photosensitive drum, the photosensitive housing, and the first contact member whose position has been adjusted in advance according to claim 4.

6. a step of temporarily fastening the first contact member with the screw and then welding the first contact member to the photosensitive member housing; a step of temporarily fastening the second contact member with the screw and then welding the second contact member to the development housing; 6. The method of claim 5, further comprising:

Images