JPH09166898A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly and easily position a 2nd housing at an attaching position in a 1st housing, and to rapidly and accurately attach each photoreceptor drum and each exposure device to each prescribed position in the 1st housing. SOLUTION: A holding part 5 for a sliding member 4 holds so that the position of the 2nd housing 15 with respect to positioning reference parts 7 can be changed. And also, in the 1st housing 1, each drum shaft 41 is installed so that the shaft can be inserted into the through hole 13 of each photoreceptor drum 12 in the 2nd housing 15, and also, each exposure device 18Y to 18BK mounted on a sub frame 61 is attached to the 1st housing 1 through a positioning means 71.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus in which a second housing accommodating a plurality of image forming process units in a line can be pulled into a mounting position in the first housing.

[0002]

2. Description of the Related Art Conventionally, a plurality of image forming process units (for example, a photosensitive drum, a charger, a developing device, etc.) (4
Each) a toner image of each color is formed on the photosensitive drum of each unit by four exposure units arranged in tandem (one row) and color-coded yellow, magenta, cyan, and black, and the toner image is transferred onto the paper in a superimposed manner. An image forming apparatus is known in which a color image is obtained by doing so.

That is, as shown in FIG. 7, the image forming apparatus includes image forming process units 11Y, 11 for each color (yellow Y, magenta M, cyan C, black BK).
M, 11C and 11BK are arranged in a line in the paper transport direction at intervals. 19 is a fixing device.

The image forming process unit 11Y comprises a photosensitive drum 12 and its peripheral devices (for example, a charging device, a developing device, a transfer device, a toner collecting device, a static eliminator, etc.). The other units 11M, 11C, 11BK have the same structure.

Each image forming process unit (11Y, 1
Exposure devices (18Y, 18M, 18C, 18BK) are provided above the 1M, 11C, 11BK), respectively. Each of the exposure devices (18Y to 18BK) irradiates the laser beam while scanning it in the main scanning direction and draws an electrostatic latent image on each photosensitive drum 12 which rotates in the sub scanning direction.

The sheets in the sheet cassette 52U (52D) are picked up one by one by a sheet feeding roller 53U (53D), and the timing is adjusted by the conveyance roller 54U (54D) and the registration roller 55 to convey the sheet. The paper is fed onto the belt 56. The conveyor belt 56 is provided between the driving roller 57 and the driven roller 58 and is rotated in the X direction.

The sheet separated from the conveyor belt 56 by the drive roller 57 passes through the fixing device 19 and is discharged to the outside of the apparatus main body 1.

In such an apparatus, the color image data is theoretically separated for each color and the exposure device (18
Y, 18M, 18C, 18BK), and each process unit (11Y, 11M, 11C, 11BK) forms each color image on the paper, so full-color printing is possible.

Here, in the color image forming apparatus, as shown in FIG. 8, the image forming process units (11Y to 11BK) are housed in the second casing 15 while maintaining the above-mentioned predetermined positional relationship. , The second housing 15 as a slide member (for example, a pair of slide rails 4, 4)
The sheet conveyance path is opened by pulling it out from the mounting position in the first housing 1 via the, so that jam processing and maintenance can be easily performed.

Specifically, the first housing 1 is a base 2B.
A front frame 2 which is disposed on the upper side and is opposed to the predetermined distance.
F and rear frame 2R, both frames (2F, 2
R) and a pair of connecting members (3, 3) and the like. The tip end of each connecting member 3 projects outward from the front frame 2F, and the second housing 15
A positioning reference portion 7 is formed for positioning at the mounting position.

Each of the exposure units (18Y to 18B) is provided in the first casing 1 so as to have a predetermined positional relationship with each of the photosensitive drums 12 in the second casing 15 which is positioned and held at the mounting position.
K) is positionally adjusted and attached using an adjustment jig (for example, a fine movement stage, a CCD image sensor).

The front frame 2F has a second housing 1
An opening 3W for passing 5 is formed. In the rear frame 2R, four drive rotating bodies (for example, a drive bevel gear 21P) are provided in each image forming process unit (11Y, 11Y).
(M, 11C, 11BK) corresponding to the photosensitive drums 12 are provided so as to be rotatable. Each drive rotating body (21P)
Are each connected to a drive motor via a gear train or the like.

On the other hand, the second casing 15 includes the first casing 1
Each drive rotor (2
1P), four driven rotating bodies (for example, driven bevel gears 31P) are provided so as to be engaged (engaged) with each other in a synchronously rotatable manner. The front face portion 15F of the second casing 15 is provided with positioning engaging portions (a pair of positioning holes 17, 17) capable of engaging with the positioning reference portions (7, 7) on the first casing 1 side. It is provided.

The slide members (4, 4) are the first housing 1
It is provided on the (rear frame 2R) via the slide holding members (6, 6) so that it can be pulled out to the outside of the casing 1 and can be pulled inside. For the slide members (4, 4),
A holding portion 5P capable of fixedly holding the second housing 15 is provided. The slide holding members (6, 6) are mounted on the rear frame 2R so that the positions thereof can be adjusted in the vertical direction (H direction) and the horizontal direction (G direction).

Therefore, when the second housing 15 is held by the holding portion 5P of the slide member (4, 4) and the slide member (4, 4) is pulled in the direction of the arrow F in that state, the first housing The positioning reference portion (7, 7) on the first side is fitted into the positioning hole (17, 17) on the second housing 15 side, and the second housing 15 is positioned at the mounting position.

In this way, when the second casing 15 is positioned at the mounting position, the drive rotating bodies (21P) and the driven rotating bodies (31P) are engaged (engaged) with each other. Therefore, by rotating and driving each drive rotating body (21P), the photosensitive drum 12 of each unit (11Y to 11BK) can be rotated to perform color printing.

[0017]

By the way, in the above image forming apparatus, when the slide members (4, 4) are retracted, the positioning holes (17, 17) on the side of the second casing 15 and the first positioning holes (17, 17) are formed.
In order to fit the positioning reference portions (7, 7) on the housing 1 side smoothly and reliably, it is necessary to strictly align the slide members (4, 4) with the positioning reference portions (7, 7). There is.

Therefore, conventionally, the position of the slide holding members (6, 6) has been adjusted by moving the slide holding members (6, 6) in the directions of arrows G and H in FIG. 8, but such adjustment work is performed by the slide holding members (6, 6). Since it is housed in the narrow first housing 1, it has a drawback that it takes too much time.

When the second casing 15 is positioned at the mounting position in the first casing 1 by the cooperation of the positioning reference portions (7, 7) and the positioning holes (17, 17), Position of each driven rotary body (31P) [each photosensitive drum 12] so that each driven rotary body (31P) on the second casing 15 side engages (engages) with each drive rotary body (21P) without excess or deficiency. It is necessary to adjust the positions of the respective photosensitive drums 12 in parallel with each other, but it is difficult and time-consuming to perform both position adjustments with sufficient accuracy.

Further, each exposure device (18Y, 18M, 18
C, 18BK) are individually attached to the first housing 1 so as to have a predetermined positional relationship with the corresponding photoconductors 12 by using a dedicated adjusting jig. There is also a disadvantage that the work of mounting (18Y or the like) is troublesome.

In view of the above circumstances, the first object of the present invention is to
An object of the present invention is to provide an image forming apparatus capable of smoothly and easily attaching the second casing to the attachment position in the first casing. Further, a second object of the present invention is that when the second housing is mounted at the mounting position of the first housing, each photosensitive drum can be accurately positioned and held at a predetermined position and driven to rotate.
Another object of the present invention is to provide an image forming apparatus capable of quickly and accurately mounting each exposure unit at a predetermined position corresponding to each photosensitive drum.

[0022]

According to a first aspect of the present invention, there is provided a second casing in which a plurality of image forming process units are accommodated in a row, and a second casing in which the second casing is held by a holding portion. It is possible to position the second housing at the mounting position by engaging the slide member that is retractable at the mounting position inside the housing and the positioning engagement portion that is provided at the second housing when retracting. In an image forming apparatus equipped with a simple positioning reference unit,
The holding portion of the slide member is configured to hold the second housing so that the position of the second housing with respect to the positioning reference portion can be changed.

In the invention having such a structure, since the second housing is held by the holding portion of the slide member so that the position with respect to the positioning reference portion can be changed, the slide member is strictly aligned with the positioning reference portion. Even if it is not necessary, the position of the second housing can be appropriately changed at the time of retracting, and the positioning engagement portion can be easily engaged with the positioning reference portion.

Therefore, the second casing can be smoothly and easily attached to the attachment position in the first casing.

According to a second aspect of the present invention, a second casing that accommodates a plurality of image forming process units in a row, and the second casing can be retracted to a mounting position in the first casing while being held. An image including a slide member provided in the second housing, and a positioning reference portion that engages with a positioning engagement portion provided in the second housing when retracted to position the second housing at the mounting position. In the forming apparatus, the photosensitive drums of each of the image forming process units are configured to change their mutual positions.
Of the photosensitive drum, the through-hole is formed along the axis of the housing, and is inserted into the through-hole of each photosensitive drum when the second housing is pulled into the mounting position in the first housing. A plurality of drum shafts are rotatably provided in the first casing so that the respective tip portions are fitted into the bearing portions on the second casing side, and the drum shafts and one end portions of the photosensitive drums are provided. , The second
An engaging body that engages when the housing is positioned at the mounting position and connects the drum shafts and the photosensitive drums in a synchronously rotatable manner is provided, and each exposure device that can expose each photosensitive drum is supported. The body is attached to the body so that its position can be adjusted, and the support is attached to the first body.
It is characterized in that it is attached to the housing of (1) through a positioning means.

In the invention having such a structure, when the second casing is pulled into the mounting position of the first casing through the slide member, the drum shafts on the first casing side are exposed to the respective photosensitive drums on the second casing side. The drum shaft is inserted through the through hole, and the tip end of each drum shaft is fitted into the bearing portion provided in the second housing. Further, both engaging bodies provided on the respective drum shafts and the respective photosensitive drums engage with each other, so that the respective drum shafts and the respective photosensitive drums are coupled so as to be rotatable in synchronization.

Therefore, when the second casing is positioned at the mounting position of the first casing, the photoconductor of each image forming process unit is accurately positioned and held at each predetermined position and can be smoothly rotated.

Further, each exposure unit is mounted on the support body outside the first housing after adjusting the mutual position and the like, and then the support body is attached to the first housing through the positioning means. Each exposure unit can be quickly and accurately positioned at each predetermined position corresponding to each photosensitive drum.

According to a third aspect of the present invention, the first casing has an upright frame which is erected on the base and rotatably supports the respective drum shafts, and the upright frame is elastically deformable to a mounting portion of the base. It is characterized in that the screw is fastened through a flexible elastic member.

In the invention having such a structure, the standing frame is screwed to the mounting portion of the base through the elastic member. Even if a force to deform the upright frame is generated by the screw fastening, the force is absorbed by the elastic deformation of the elastic member, and is not transmitted to the upright frame.

As a result, the standing frame is prevented from being deformed, and each drum shaft can be held at the proper position.
Therefore, it is possible to prevent the shake of each drum shaft when each photosensitive drum rotates, and reduce the load fluctuation due to the frictional force between each drum shaft and the bearing portion.

As a result, each photosensitive drum can be driven to rotate more smoothly.

[0033]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) As shown in FIGS. 1 to 4, this image forming apparatus has the same basic configuration as the conventional example (FIGS. 7 and 8), but holds the slide members (4, 4). The part 5 is configured to be able to hold the second housing 15 with a so-called backlash.

The same components as those of the conventional example (FIGS. 7 and 8) are designated by the same reference numerals, and the description thereof will be simplified or omitted.

The holding portion 5 of the slide member (4, 4) holds the second casing 15 so that the position with respect to the positioning reference portion (7, 7) can be changed. In this embodiment, the holding portion 5 is a support plate with holes (8, 8) capable of holding a pair of support pins (16, 16) projectingly provided on both side surfaces of the second housing 15 with so-called looseness. Are formed from.

The supporting plates (8, 8) are shown in FIG.
As shown in (B), the support pin (1
6, 16) are formed with holes (8h, 8h) that hold the (6, 16) movable in the vertical direction (H direction) and the horizontal direction (G direction) and swingable in the arrow J direction.

Each image forming process unit (11
As shown in FIGS. 1 and 3, a through hole 13 is formed along the axis of the photosensitive drum 12 of Y, 11M, 11C, 11BK), and a driven rotating body (for example, The spline shaft member 31) is directly connected.

Further, when the second housing 15 is drawn into the first housing 1 via the slide members (4, 4) to the mounting position in the first housing 1, each photosensitive member is exposed. A plurality of drum shafts 41 are provided, each of which is inserted through the through hole 13 of the drum 12 and has its tip portion fitted into each bearing portion 49 on the second casing 15 side.

As shown in FIG. 3, each drum shaft 41 is rotatably supported on the rear frame 2R via a bearing 48, and is rotationally driven by a drive motor connected via a power transmission mechanism (not shown). . Each drum shaft 41 is formed to have a diameter slightly smaller than the through hole 13 of each photosensitive drum 12 and longer than the axial length of the photosensitive drum 12.

A drive rotor (for example, the spline hole member 21) is mounted on each drum shaft 41 so as to be movable only in the axial direction. Each drive rotating body (21)
An opening is formed in the spline hole 22 that can mesh with the corresponding driven rotating body (31).

Each drive rotating body (21) and rear frame 2R
A biasing spring 26 is interposed between and. The biasing spring 26 includes a driving rotating body (21) and a driven rotating body (31).
The second casing 15 is pressed in a state where and mesh with each other to position and hold the second casing 15 at a predetermined position in the first casing 1.

Next, the operation of this embodiment will be described. In order to position and hold the second casing 15 at the mounting position in the first casing 1, each support pin 16 of the second casing 15 is held.
The second casing 15 is held by the slide members (4, 4) by fitting the second housing 15 into the corresponding holes 8h of the support plates 8.

Next, in this state, the second casing 15 is pushed into the first casing 1 side. Then, the second housing 15 is drawn into the first housing 1 while being held by the slide members (4, 4). By this retracting operation of the second casing 15, each drum shaft 41 on the first casing 1 side is moved to the second casing 15 side.
It is inserted into the through hole 13 of each of the photosensitive drums 12 housed therein and moves relatively.

When the positioning holes (17, 17) of the second casing 15 approach the positioning reference portions (7, 7) of the first casing 1, the second casing 15 is pushed in. Is temporarily stopped, and it is confirmed whether the positioning holes (17, 17) and the positioning reference portions (7, 7) are aligned.

If they match, the second housing 15
Is pushed in as it is, and the positioning holes (17, 17) and the positioning reference portions (7, 7) are fitted to each other. This allows
Each driven rotary body (31) meshes with each drive rotary body (21), and the second casing 15 is positioned and held at the mounting position in the first casing 1. At this time, the tip end portion of each drum shaft 41 is fitted and inserted into the bearing portion 49 of the second housing 15, and as a result, each drum shaft 41 is supported at both ends.
The housing 15 is stably held at the mounting position.

While the slide members (4, 4) are being retracted, the second casing 15 is moved to the slide members (4, 4) by G,
Since the slide members (4, 4) are held with play in the H, J directions, the position of the slide members (4, 4) is not restricted in the G, H, J directions. Therefore, the slide members (4, 4) smoothly slide with the slide holding members (6, 6) and no unpleasant rubbing noise or the like is generated.

If they do not match, the second housing 15
Are moved in the G and H directions or swung in the J direction, and the positioning holes (17, 17) and the positioning reference portion (7,
7) is aligned, and the second casing 15 is pushed in in that state.

According to the first embodiment, however,
The holding portion 5 of the slide member (4, 4) is attached to the second housing 15
Since the position of the second housing 15 is changeably held with respect to the positioning reference portion (7, 7), the second housing 15 can be smoothly and accurately positioned and held at the mounting position in the first housing 1.
Therefore, the assembly time can be shortened and the manufacturing cost can be reduced.

Further, since the second casing 15 can be accurately positioned and held at the mounting position, the photosensitive drum 12 and the exposure device (18) of each image forming process unit (11Y to 11BK) can be held.
(Y-18BK) and the like, the relative position accuracy is improved, and the image quality can be improved.

Further, since the second casing 15 is loosely held by the slide members (4, 4), the position of the slide members (4, 4) is not regulated. Therefore, the slide members (4, 4) smoothly slide with the slide holding members (6, 6) and no unpleasant rubbing noise or the like is generated.

Furthermore, since the holding portion 5 is formed by the pair of support plates (8, 8), the structure is not complicated and the size is not increased.

As shown in FIG. 4, the rear frame 2R is formed by using the rear frame 2R which is press-processed (drilling process or the like) to form the through hole 41h of each drum shaft 41 and the connecting member mounting hole 3h. Rear part 15R and front part 1
If 5F is manufactured, the positions of the holes 41h (3h) will be the same, and the drum shafts 41 will pass through the through holes 13 of the photosensitive drums 12.
It can be inserted more smoothly and surely. Further, the positioning hole 17 and the positioning reference portion 7 can be engaged more smoothly and reliably.

(Second Embodiment) The second embodiment is shown in FIG. The image forming apparatus according to the second embodiment is configured to expose each of the photosensitive drums 12 positioned and held at a predetermined position of the first housing 1 with each exposure device (18Y, 18M,
18C, 18BK) support (for example, sub-frame 6
The support member (61) is mounted on the first housing 1 so that its position can be adjusted, and the support member (61) is mounted on the first housing 1 via the positioning means 71.

The same components as those in the first embodiment (FIGS. 1 to 4) are designated by the same reference numerals, and the description thereof will be simplified or omitted.

The sub-frame 61 includes the exposure units (18Y,
18M, 18C, 18BK) are formed so that their positions can be adjusted by using fixing means such as screws.

The positioning means 71 includes a plurality of (for example, three) support shafts (72, 73, 74) whose both ends are supported by the front frame 2F and the rear frame 2R of the first housing 1, respectively. Positioning holes (7) provided in the support shaft (74) and formed in the sub-frame 61
6, 76) and the positioning pins (66, 66) that can be fitted to each of the photosensitive drums 12 corresponding to the position-adjusted exposure devices (18Y, 18M, 18C, 18BK) mounted on the sub-frame 61. Is formed so as to be positioned at a position having a predetermined positional relationship with.

Here, each of the exposure devices (18Y to 18B)
K) is temporarily fixed to the sub-frame 61, and a position adjusting jig (for example, a sensor jig 65) adjusts the position so that the variations in the parallelism of the scanning lines and the variations in the main scanning width are within the allowable range. Fixed after.

The sub-frame 61 is positioned in the left-right, front-rear, and up-down directions by the positioning means 71 and attached to the first housing 1.

However, according to the second embodiment,
Since each exposure unit (18Y to 18BK) is position-adjusted and mounted on the sub-frame 61 and the sub-frame 61 is attached to the first housing 1 using the positioning means 71, each exposure unit (18Y to 18BK) is attached. The photosensitive drums 12 can be quickly and accurately attached at predetermined positions corresponding to the photosensitive drums 12.

Further, the number of assembling steps can be reduced and the cost can be reduced.

In this second embodiment, the standing frames (2F, 2R) forming the first casing 1 are the base 2
A plurality of (for example, four) mounting portions 9 provided on B are screw-fastened via elastic members (81).

Specifically, each mounting portion 9 is attached to the base 2B.
Are provided so as to be spaced apart in the front-rear and left-right directions, and through holes 9h for passing the screws 85 are formed in each mounting portion 9 (in FIG. 5, only the mounting portion 9 on the front side is shown. ing).

A plurality of (four) collars 81 as elastic members are made of rubber and are formed in a cylindrical shape so that screws 85 can be fitted therein. Each collar 81 has the same length and the same material, and has the same elastic characteristic.

As shown in FIG. 6, a female screw 86 which can be screwed into the screw 85 is screwed to a portion of the front frame 2F and the rear frame 2R corresponding to each mounting portion 9.

Each frame (2F, 2R) has a base 2B.
The screw 85 is fixed to each of the mounting portions 9 through the collar 81 by screwing the screw 85 with the female screw 86 and tightening. Here, each frame (2F, 2
Even if a force to deform (R) is generated, the force is absorbed by elastic deformation of each collar 81, and is not transmitted to each frame (2F, 2R).

As a result, the deformation of each frame (2F, 2R) is prevented, and each drum shaft 41 (positioning reference portion 7).
Can be held in a regular position. Therefore, it is possible to prevent the shake of each drum shaft 41 when each photosensitive drum 12 rotates, and also to prevent each drum shaft 41 and the bearing portion 49 from rotating.
The load fluctuation due to the frictional force between and can be reduced. As a result, the photosensitive drums 12 can be driven to rotate more smoothly.

[0067]

According to the first aspect of the invention, since the holding portion of the slide member is configured to hold the second casing so that the position with respect to the positioning reference portion can be changed, the second casing can be changed to the first casing.
It can be smoothly and easily positioned at the mounting position in the housing.

According to the second aspect of the present invention, the first housing is provided with the respective drum shafts through which the through holes of the respective photosensitive drums in the second housing can be inserted, and the position of each exposure device is adjusted on the support. Since the supporting body is attached to the first casing through the positioning means after the mounting, the photosensitive drums in the second casing are accurately positioned and held at the predetermined positions to be smoothly rotated. be able to. Further, each exposure unit can be quickly and accurately attached to each predetermined position corresponding to each photosensitive drum.

According to the third aspect of the present invention, since the standing frame forming the first casing is screwed to the mounting portion of the base via the elastic member, the elastic member absorbs the deforming force generated at the time of fastening. It is possible to prevent deformation of the standing frame. Therefore, the photosensitive drums in the second housing can be driven to rotate more smoothly.

[Brief description of the drawings]

FIG. 1 is a perspective view for explaining a first embodiment of the present invention.

FIG. 2 is also a diagram for explaining a holding portion of the slide member.

FIG. 3 is a diagram similarly showing a state in which the second casing is positioned at the mounting position in the first casing.

FIG. 4 is also a diagram for explaining a method of manufacturing the front part and the rear part of the second housing by using the rear frame of the first housing.

FIG. 5 is a diagram for explaining a second embodiment of the present invention.

FIG. 6 is a view showing a state where the frame of the first housing and the base are screwed together.

FIG. 7 is a diagram illustrating a conventional configuration of an image forming apparatus.

FIG. 8 is a diagram for explaining the positional relationship between the first and second casings and the slide member.

[Explanation of symbols]

1 First Housing 2F Front Frame 2R Rear Frame 4 Sliding Member 5 Holding Section 8 Support Plate 7 Positioning Reference Section 11Y, 11M, 11C, 11BK Image Forming Process Unit 12 Photosensitive Drum 15 Second Housing 16 Support Pin 17 Positioning hole (positioning engagement part) 21 Spline hole member (driving rotary body) 31 Spline shaft member (driven rotary body) 41 Drum shaft 49 Bearing portion 61 Subframe (supporting body) 71 Positioning means 81 Color (elastic member)

Claims (3)

[Claims] 1. A second housing accommodating a plurality of image forming process units in a row, and a second housing provided so as to be retractable into a mounting position in the first housing while being held by a holding portion. Image forming apparatus provided with a sliding member and a positioning reference portion capable of engaging with a positioning engaging portion provided in the second housing when retracted and positioning the second housing at the mounting position. In the image forming apparatus, the holding portion of the slide member is configured to hold the second housing so that the position of the second housing with respect to the positioning reference portion can be changed. 2. A second casing accommodating a plurality of image forming process units in a line, and a slide provided so as to be retractable to an attachment position in the first casing while holding the second casing. An image forming apparatus comprising: a member; and a positioning reference portion that engages with a positioning engaging portion provided in the second housing when retracted and is capable of positioning the second housing at a mounting position. The photosensitive drum of each image forming process unit is housed in the second housing so that the mutual position can be changed, and a through hole is formed along the axis of the second housing, and the second housing is the first housing. When a plurality of drum shafts are inserted into the through holes of the respective photosensitive drums and the respective tip portions are fitted into the respective bearing portions on the second casing side when retracted to the mounting position in the body, the plurality of drum shafts are provided in the first casing. Rotatably mounted on each drum shaft and one end of each photosensitive drum An exposure member that exposes each photosensitive drum by providing an engaging body that engages when the second housing is positioned at the mounting position and connects each drum shaft and each photosensitive drum in a synchronously rotatable manner. An image forming apparatus, wherein each possible exposure device is mounted on a support body so that its position can be adjusted, and the support body is attached to the first housing via a positioning means. 3. The first casing has a standing frame that is erected on a base and rotatably supports the drum shafts, and the standing frame is attached to a mounting portion of the base via an elastic member that is elastically deformable. The image forming apparatus according to claim 2, wherein the image forming apparatus is screwed.