JP6415664B1 - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure a distance between a handle portion and a belt while suppressing an increase in size of the belt unit in a configuration in which a rotatable handle portion is attached to the belt unit. Furthermore, a belt unit capable of attaching a handle with a small number of parts is provided. A shaft that rotatably supports a handle includes a large-diameter portion and a small-diameter portion, and a through hole provided in the handle portion includes a first hole portion into which the small-diameter portion is fitted, and a first hole. And a second hole portion which is communicated with the portion in the direction orthogonal to the axial direction and into which the large diameter portion can be inserted. A protrusion is formed between the first hole and the second hole, and the gap formed by the protrusion is narrower than the outer diameter of the small diameter portion. The shaft includes a D-cut portion that is narrower than the gap formed by the protrusion, and the shaft is configured to be movable between the first hole portion and the second hole portion when the D-cut portion faces the gap. When the shaft is in the mounting position, the movement of the shaft portion between the first hole portion and the second hole portion is restricted by the protruding portion. [Selection] Figure 9

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, or a facsimile apparatus using an electrophotographic system or an electrostatic recording system.

  Image forming apparatuses such as printers and copiers are required to have a small size and high functionality. Accordingly, each unit in the apparatus is required to have a space-saving design. On the other hand, in order to continue providing a stable image to the user, each unit in the apparatus is regularly maintained and replaced. For this reason, the unit is provided with a handle member from the viewpoint of operability, and the user and the service person support the handle member and carry the unit, so that the workability is good.

Japanese Unexamined Patent Publication No. 2017-45014

  Conventionally, for example, Patent Document 1 proposes a configuration in which a handle member for gripping a belt unit is attached to a shaft member.

  As a configuration for assembling the handle member to the shaft member, a configuration in which the shaft member is passed through a cylindrical hole provided in the handle member is conceivable. However, in order to reduce the size of the unit, the grip member provided on the shaft member may come into contact with the belt member in the configuration in which the belt member that is circulated and the shaft member described above are arranged close to each other. When the handle member and the belt member come into contact with each other, the belt member is damaged, and the toner image transferred at the damaged portion of the belt member is disturbed to cause an image defect. Therefore, it is desirable to keep the distance between the handle member and the belt member as far as possible. In order to reduce the distance between the handle member and the belt member, it is only necessary to minimize the shaft diameter of the shaft member while ensuring the minimum thickness of the handle member. However, if the diameter of the entire shaft member is reduced, the strength of the shaft member is reduced and the shaft member is bent. Therefore, a configuration is conceivable in which only the region to which the handle member is attached is reduced in diameter, and the handle member is attached to the small diameter portion. Thus, when the structure which inserts the shaft member from which a shaft diameter differs in a handle member is employ | adopted, the following shapes can be considered as a through-hole which lets a shaft member pass a handle member. First, a hole for a large diameter portion for inserting the large diameter portion of the shaft member is provided. And after the small diameter part of a shaft member is inserted in the through-hole of a handle member, it is possible to provide the hole part for small diameter parts fitted with the small diameter part of a shaft member. At this time, a fixing member for fixing the shaft member to the handle member is necessary so that the small diameter portion of the shaft member does not come out of the hole for the small diameter portion. For this reason, there was a problem that the number of parts will increase.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image forming apparatus in which a handle member can be attached with a small number of parts while suppressing an increase in size in an image forming apparatus in which a handle member is attached to a shaft member provided in a belt unit. There is.

  An image forming apparatus according to the present invention includes an image carrier that carries an image, a belt unit that is detachably provided on the apparatus main body and onto which a toner image carried by the image carrier is transferred, and the belt unit. And a handle part for gripping the belt unit when the belt unit is taken out from the main body of the apparatus, and a through hole provided in the handle part. An image forming apparatus comprising: a shaft that rotatably supports the handle portion, wherein the shaft includes a first shaft portion and a second shaft portion that is thicker than the first shaft portion; The through hole is provided at a position different from the first hole portion with respect to a first hole portion into which the first shaft portion can be fitted and a direction orthogonal to the axial direction of the shaft, A second hole part into which the second shaft part can be inserted, and the first hole part A communication portion for communicating the second hole portion, and the handle portion is provided at a position facing the first shaft portion when the handle unit is attached to the belt unit, and the gap of the communication portion is the A projection that protrudes from the inner surface of the through-hole so as to be narrower than the outer diameter of the first shaft, and the shaft has a thickness in a predetermined direction perpendicular to the axial direction of the shaft; A third shaft portion that is smaller than the protrusion portion and has a length in the axial direction of the shaft that is longer than the protrusion portion, and the shaft is in communication with the communication portion when the third shaft portion is in a position facing the protrusion portion. It is configured to be able to pass through the section.

  According to the present invention, in the image forming apparatus in which the handle member is attached to the shaft member provided in the belt unit, it is possible to provide an image forming apparatus in which the handle member can be attached with a small number of parts while suppressing an increase in size. it can.

Schematic sectional view of the image forming apparatus Schematic sectional view of the intermediate transfer belt unit during image formation Schematic sectional view of the intermediate transfer belt unit in the first state Schematic sectional view of the intermediate transfer belt unit in the second state Schematic perspective view of the state when carrying the intermediate transfer belt unit Schematic perspective view around the grip member of the intermediate transfer belt unit Schematic perspective view of the handle member Schematic cross-sectional view around the D-cut part Schematic perspective view and schematic sectional view in the vicinity of the shaft member and the handle member Schematic perspective view and schematic sectional view when assembling the handle member Schematic perspective view of handle member (Example 2) Schematic perspective view and schematic sectional view when assembling the handle member (Example 2) Schematic perspective view of handle member (conventional configuration) Schematic perspective view and schematic sectional view of the vicinity of the shaft member and the handle member (conventional configuration) Schematic perspective view and schematic sectional view when assembling the handle member (conventional example)

[Example 1]
Exemplary embodiments of the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

<Overall Configuration and Operation of Image Forming Apparatus>
FIG. 1 is a schematic cross-sectional view of an intermediate transfer type tandem color digital printer having four image forming units as viewed from the front, as an image forming apparatus 100 to which the present invention is applied. First, an outline of the image forming apparatus 100 will be described.

  The image forming apparatus 100 includes an intermediate transfer belt unit 10 in which an intermediate transfer belt 17 is stretched and supported at a middle position. Under the intermediate transfer belt unit 10, image forming units 106 a to 106 d for forming yellow, magenta, cyan, and black toner images on the intermediate transfer belt 17 are provided. The image forming units 106a to 106d are respectively provided with photosensitive drums 101a to 101d as image carriers, and the surfaces are charged with uniform charges by the charging rollers 102a to 102d. Image signals of yellow, magenta, cyan, and black are input to the laser scanners 103a to 103d, respectively, and the surfaces of the photosensitive drums 101a to 101d are irradiated with laser light in accordance with the image signals to neutralize charges and electrostatically A latent image is formed. The electrostatic latent images are visualized as toner images of respective colors by the developing devices 104 a to 104 d, respectively, and then primary transferred sequentially to the intermediate transfer belt 17 to form a full color toner image on the intermediate transfer belt 17. The toner agent remaining on the photosensitive drums 101a to 101d is collected by the drum cleaners 105a to 105d.

  On the other hand, the transfer material P such as paper fed from any of the feeding units 111 and 112 or the manual feeding unit 113 is fed one by one through the feeding roller 110, the feed roller 114, and the retard roller 115. Sent to pair 116. When the leading edge of the transfer material P comes into contact with the stopped registration roller, a loop is formed, and the registration roller is started to rotate in synchronization with the toner image on the intermediate transfer belt 17.

  The toner image on the intermediate transfer belt 17 is transferred to the transfer material P by the secondary transfer outer roller 108 and the secondary transfer portion 107 formed by the intermediate transfer belt 17 and fixed by the fixing device 109 by heat and pressure. Thereafter, the transfer material P is discharged from the paper discharge unit 117a or 117b to the paper discharge trays 118a and 118b outside the apparatus. Further, the toner agent that is not transferred in the secondary transfer unit 107 and remains on the intermediate transfer belt 17 is collected by the intermediate transfer belt cleaner 50.

<Intermediate transfer belt unit>
Next, the intermediate transfer belt unit 10 will be described with reference to FIGS. FIG. 2 is a schematic cross-sectional view of the intermediate transfer belt unit 10 during full color image formation. FIG. 3 is a schematic cross-sectional view of the intermediate transfer belt unit 10 during monochrome image formation (first state). FIG. 4 is a schematic cross-sectional view of the intermediate transfer belt unit 10 in the second state, which is located during maintenance such as belt replacement. FIG. 5 is a schematic perspective view showing a state when the intermediate transfer belt unit 10 is carried, and FIG. 6 is a schematic perspective view showing a configuration around the grip member of the intermediate transfer belt unit 10.

  2 to 4, the intermediate transfer belt 17 using polyimide or the like is stretched by five rollers including a secondary transfer inner roller 11, a steering roller 12, a tension roller 13, an auxiliary roller 14, and an idler roller 15. Has been. These rollers 11 to 15 are rotatably supported by bearings (not shown) at both ends. In this embodiment, the steering roller 12 also functions as a driving roller, and will be described with the same reference numerals. However, it is not always necessary to use the steering roller 12 as a driving roller. For example, the idler roller 15 or the secondary transfer inner roller 11 shown in FIG.

  The surface of the driving roller 12 is formed of a rubber layer having a high friction coefficient so as to convey the intermediate transfer belt 17 without slipping. The intermediate transfer belt 17 is applied with tension by being pressed from the inner surface of the belt by the tension roller 13. The intermediate transfer belt 17 is conveyed in a counterclockwise direction (see an arrow 200 in FIG. 2) when the steering roller 12 also serving as a driving roller is rotationally driven.

  Between the idler roller 15 and the auxiliary roller 14 that stretch the intermediate transfer belt 17, primary transfer rollers 16 a to 16 d are disposed at positions facing the photosensitive drums 101 a to 101 d of the respective colors. The primary transfer rollers 16a to 16d are rotatably supported at both ends by bearings (not shown), and pressurize the intermediate transfer belt 22 from the inner surface by elastic members (not shown). Thus, the intermediate transfer belt 17 is sandwiched between the primary transfer rollers 16a to 16d and the photosensitive drums 101a to 101d (see FIG. 2).

<Photosensitive drum separation mechanism>
The intermediate transfer belt unit 10 is configured to be switchable between a first state in which the intermediate transfer belt 17 and at least one photosensitive drum are in contact with each other and a second state in which the intermediate transfer belt 17 and all the photosensitive drums are separated from each other. Is done. Switching between the first state and the second state is performed by rotation of a shaft member 20 that is rotatably provided to the intermediate transfer belt unit 10. That is, when the shaft member 20 rotates, the intermediate transfer belt 17 and the photosensitive drum can be brought into contact with and separated from each other. In the present embodiment, the rotation of the shaft member 20 is configured such that the operator switches the first state to the second state by turning a lever fixed to the shaft member 20. In addition, although this embodiment demonstrated the case where it switches from a 1st state to a 2nd state, it is not limited to this. For example, as shown in FIG. 2, the shaft member 20 can also be applied to switch from a state in which the photosensitive drum 101 of each color is in contact with the intermediate transfer belt 17 (all contact state) to the second state. The operation of switching between the first state and the second state of the intermediate transfer belt unit 10 will be described in more detail below. The intermediate transfer belt unit 10 is provided with a support shaft 27 on the left outer side of the yellow primary transfer roller 16a disposed at the left end when viewed from the front of the image forming apparatus, substantially parallel to the axial direction of the stretching roller. The support shaft 27 engages with a storage portion 28 a of a support member 28 provided in the frame unit 18, and the frame unit 18 can rotate around the support shaft 27 via the support member 28. Further, the intermediate transfer belt unit 10 is provided with a shaft member 20 supported so as to be rotatable in the vicinity of both end portions substantially parallel to the axial direction of the stretching roller, and further, a moving member 25 is provided in the vicinity of both end portions. Fixed. The moving member 25 is provided with a guide groove 25a. The guide groove 25a has a curved surface, and is a cam whose distance from the shaft member 20 gradually changes according to the rotation angle of the moving member 25. On the other hand, both front and back side surface portions of the belt frame unit 18 as viewed from the front of the image forming apparatus are provided with guide shafts 26 protruding outward, and the guide shafts 26 are configured to engage with the guide grooves 25a. (See FIG. 3). In the first state of the intermediate transfer belt unit 10, when the shaft member 20 is rotated counterclockwise as viewed from the front of the image forming apparatus, the moving member 25 and the guide groove 25a rotate the shaft member 20 in conjunction with the rotation. It rotates counterclockwise about the center of movement. At this time, the guide shaft 26 of the frame unit 18 is engaged with the guide groove 25a, and the guide shaft 26 moves substantially upward in the gravitational direction while contacting the curved surface of the guide groove 25a by the rotation of the shaft member 20. As a result, the frame unit 18 rotates counterclockwise around the support shaft 27 via the movement of the guide shaft 26. When the rotation of the shaft member 20 is completed, the intermediate transfer belt 17 provided in the frame unit 18 and all the photosensitive drums 101a to 101d are separated from each other, and the intermediate transfer belt unit 10 is in the second state (see FIG. 4). ).

  The intermediate transfer belt unit 10 is configured to be detachable from the apparatus main body when in the second state in which the intermediate transfer belt 17 and all the photosensitive drums are separated. When the intermediate transfer belt unit 10 is in the second state, the distance between the intermediate transfer belt 17 and the photosensitive drums 101a to 101d and components provided below the intermediate transfer belt unit 10 in the gravity direction is secured. Therefore, workability is good when the intermediate transfer belt unit 10 is attached to and detached from the main body of the image forming apparatus. In the present embodiment, the attachment / detachment direction of the intermediate transfer unit 10 with respect to the main body of the image forming apparatus is a direction in which the intermediate transfer unit 10 is pulled out to the front side when viewed from the front of the image forming apparatus. That is, the intermediate transfer belt unit 10 is detachable through an opening provided on a side surface orthogonal to the axial direction of the photosensitive drums 101a to 101d. After the intermediate transfer belt unit 10 is pulled out from the main body of the image forming apparatus, the handle member 21 and the handle portion 19 provided in the intermediate transfer belt unit 10 are supported to facilitate the carrying of the intermediate transfer belt unit 10 ( (See FIG. 5).

<Belt unit handle member>
As shown in FIG. 5, the handle portion 19 is disposed above the intermediate transfer belt 17 in the vertical direction. The handle portion 19 is provided at a position overlapping the intermediate transfer belt 17 when viewed from a direction orthogonal to the axial direction of the shaft member 20. The handle member 21 is provided in the shaft member 20 so as to be rotatable about the shaft member 20 as a rotation center. The shaft member 20 includes a first shaft portion 20a at a position where the shaft member 20 and the handle member 21 are engaged, and a second shaft portion 20b at other positions. That is, the shaft member 20 has the first shaft portion 20a positioned inside the through hole when the handle member 21 is attached to the intermediate transfer belt unit 10. Further, the shaft member 20 has a second shaft portion 20 b positioned outside the through hole when the handle member 21 is attached to the intermediate transfer belt unit 10. The outer diameter of the first shaft portion 20a is smaller than that of the second shaft portion 20b. Therefore, the outer shape of the handle member 21 that engages with the first shaft portion 20a can be reduced. A detailed configuration of the radial positioning of the handle member 21 with respect to the first shaft portion 20a will be described later. Further, the intermediate transfer belt unit 10 is provided with a frame member 23 that rotatably supports both end portions of the shaft member 20, and the frame member 23 is provided with a storage portion 23 a in which the handle member 21 can be stored. The position of the handle member 21 in the axial direction of the shaft member 20 is restricted by the position restricting portions 23b and 23c provided in the storage portion 23a and the side surface portions 21d and 21e of the handle member 21 coming into contact with each other. An elastic member 24 is engaged with the shaft member 20, and the handle member 21 is elastically urged by the elastic member 24 in a direction in which the handle member 21 is stored in the storage portion 23a (a circumferential direction of the shaft member 20) (see FIG. 6). Thus, when carrying the intermediate transfer belt unit 10, the handle member 21 is lifted against the elastic force of the elastic member 24 with the shaft member 20 as the rotation center. In other cases, the handle member 21 is always stored in the storage portion 23a, so that the intermediate transfer belt unit 10 can be downsized.

<Assembly and positioning of handle members>
Next, assembly of the handle member 21 with respect to the shaft member 20 and positioning in the radial direction in the configuration of the present embodiment will be described with reference to FIGS. FIG. 7 is a schematic perspective view of the handle member. FIG. 8 is a schematic perspective view of the periphery of the D-cut portion 20 d of the shaft member 20.

  FIG. 9A is a schematic perspective view of a state in which the handle member 21 is assembled to the shaft member 20. FIG. 9B is a schematic cross-sectional view showing a cross section of a plane parallel to the planar portion 20c in the state of FIG. 9A. FIG.9 (c) is a schematic sectional drawing of the handle member 21 engaging part in the state of Fig.9 (a).

  FIG. 10A-1 is a schematic perspective view showing a state where the second shaft portion 20b passes through the second through hole 21b in the assembly according to the present embodiment. FIG. 10A-2 is a schematic cross-sectional view showing a cross section of a plane parallel to the plane portion 20c in the state of FIG.

  FIG. 10B-1 is a schematic perspective view of a state in which the D-cut portion 20d (see FIG. 8) of the first shaft portion 20a faces the protrusion 21c. FIG. 10B-2 is a schematic cross-sectional view showing a cross section of a plane parallel to the plane portion 20c in the state of FIG.

  FIG. 10C-1 is a schematic perspective view showing a state where the first shaft portion 20a has moved to the first through hole 21a. FIG. 10C-2 is a schematic cross-sectional view showing a cross section of a plane parallel to the plane portion 20c in the state of FIG. FIG.10 (c-3) is a schematic sectional drawing of the handle member 21 engaging part in the state of FIG.10 (c-1).

  The shaft member 20 includes a first shaft portion 20a at a position where the handle member 21 is engaged in the axial direction of the shaft member 20, and a second shaft portion 20b at another position outside the engaging position. The outer diameter of the first shaft portion 20a is smaller than the outer diameter of the second shaft portion 20b. Further, the first shaft portion 20a is provided with a D-cut portion 20d including a flat surface portion 20c. The D cut portion 20d has a thickness in a predetermined direction smaller than the shaft diameter of the first shaft portion 20a. The D-cut portion 20 d has an arc portion centered on the axis of the shaft member 20 and a plane portion 20 c parallel to the axis of the shaft member 20. The handle member 21 is provided with a through hole in the axial direction of the shaft member 20 so that the shaft member 20 can be inserted. The through hole has a first through hole 21a (first hole portion) that can be fitted into the first shaft portion 20a of the shaft member 20 when the handle member 21 is mounted, and a second shaft portion 20b. It has the 2nd through-hole 21b (2nd hole part) which can pass. The first through hole 21 a and the second through hole 21 b communicate with each other in a direction orthogonal to the axial direction of the shaft member 20. That is, a communication portion is formed between the first through hole 21a and the second through hole 21b. A protrusion 21c is provided between the first through hole 21a and the second through hole 21b. The through hole surrounded by the first through hole 21a and the protrusion 21c has a size that allows the first shaft portion 20a to be fitted.

  That is, in the present embodiment, the inner surface of the through hole has a protrusion 21c protruding from the inner surface of the through hole so that the gap between the through holes is narrowed between the first through hole 21a and the second through hole 21b. Is formed.

  The protrusion 21c has a width in the axial direction of the shaft member 20 that is smaller than the groove width of the D-cut portion 20d (length in the axial direction of the flat surface 20c). The distance between the gap H1 formed by the first through hole 21a and the protrusion 21c is larger than the thickness H2 between the flat portion 20c and the outer diameter portion of the first shaft portion 20a (FIGS. 7 to 7). 9).

  Moreover, the distance of the clearance gap H1 formed of the 1st through-hole 21a and the projection part 21c is smaller than the outer diameter of the 1st axial part 20a. Here, if the distance of the gap H <b> 1 is too large, the shaft member 20 comes off to the second through hole 21 b side after the handle member 21 is attached to the shaft member 20. On the other hand, when the distance of the gap H1 is too narrow, the thickness H2 of the D-cut portion 20d becomes too small. Therefore, in the present embodiment, the distance of the gap H1 is between the outer diameter of the first shaft portion 20a −1 mm and the outer diameter of the first shaft portion 20a × 60%. Preferably, the distance of the gap H1 is between the outer diameter of the first shaft portion 20a -1.5 mm and the outer diameter of the first shaft portion 20a -2.5 mm. In other words, the difference between the distance of the gap H1 and the outer diameter of the first shaft portion 20a is preferably greater than 1 mm and less than 40 of the outer diameter of the first shaft portion 20a. The difference between the distance of the gap H1 and the outer diameter of the first shaft portion 20a is greater than 1.5 mm and more preferably less than 2.5 mm.

  Next, assembly of the shaft member 20 and the handle member 21 will be described. First, the second shaft portion 20b of the shaft member 20 is passed through the second through hole 21b of the handle member 21 in the axial direction. The direction of passage of the shaft member 20 in the present embodiment is a direction from the back side to the front side when viewed from the front of the image forming apparatus (see FIG. 10A). When the second shaft portion 20b passes through the second through hole 21b in the axial direction, the D-cut portion 20d and the projection portion 21c of the first shaft portion 20a face each other (see FIG. 10B). From this state, in the first shaft portion 20a, the thickness H2 between the flat surface portion 20c and the outer diameter portion of the first shaft portion 20a passes through the gap H1 formed by the first through hole 21a and the protruding portion 21c. Then, the second through hole 21b moves to the first through hole 21a (see FIG. 10C). After the first shaft portion 20a moves into the first through hole 21a, the first shaft portion 20a is further passed in the axial direction of the shaft member 20 with respect to the first through hole 21a. The direction of the passage is a direction from the back side to the front side when viewed from the front of the image forming apparatus. When the first shaft portion 20a is passed through the first through hole 21a in the axial direction of the shaft member 20, and the D-cut portion 20c and the protruding portion 21c are not at positions facing each other, the first shaft portion 20a is It will be in the state fitted to the through hole enclosed by the through hole 21a and the projection part 20c. As a result, the grip member 21 is positioned in the radial direction with respect to the shaft member 20, and can be rotated around the shaft member 20 (see FIG. 9).

  In the present embodiment, the direction in which the second shaft portion 20b passes through the second through hole 21b and the direction in which the first shaft portion 20a passes through the first through hole 21a are the same. If the above-mentioned passing directions are not the same, the amount of movement for allowing the second shaft portion 20b to pass through the second through hole 21b becomes larger than when the passing directions are the same. When the amount of movement of the shaft member 20 is increased, the arrangement of other components assembled to the intermediate transfer belt unit 10 is restricted, resulting in a complicated and large apparatus. In this embodiment, complication and enlargement of the apparatus are suppressed by using the same passing method.

  Here, the positional relationship among the first through hole 21a, the second through hole 21b, and the intermediate transfer belt 17 provided in the handle member 21 in the present embodiment will be described. In the present embodiment, the distance between the handle member 21 and the intermediate transfer belt 17 when the handle member 21 and the shaft member 20 are fitted and supported by the first through hole 21a is set to the first distance. The first distance is larger than the second distance between the handle member 21 and the intermediate transfer belt 17 when the handle member 21 and the shaft member 20 (second shaft portion 20b) are fitted in the second through hole 21b. It has become a relationship. For this reason, the distance between the handle member 21 and the intermediate transfer belt 17 can be increased by fitting the first shaft portion 20a and the first through hole 21a, and the size of the apparatus can be suppressed.

  Specifically, in the present embodiment, when the handle member 21 is stored in the storage portion 23a, the positional relationship between the first through hole 21a and the second through hole 21b with respect to the intermediate transfer belt 17 is set as follows. ing. That is, the intermediate transfer belt 17 is disposed below the shaft member 20 in the vertical direction. Furthermore, the lowest point position of the first through hole 21a and the lowest point position of the second through hole 21b when the handle member 21 is stored in the storage part 23a are set to substantially the same height. By doing so, the distance between the handle member 21 and the intermediate transfer belt 17 when the handle member 21 is attached can be increased by the difference between the shaft diameters of the first shaft portion 20a and the second shaft portion 20b. In this embodiment, the height of the lowest point position of the first through hole 21a and the lowest point position of the second through hole 21b when the handle member 21 is stored in the storage portion 23a are the same position. However, it is not limited to this. If the intermediate transfer belt is positioned downward as in the present embodiment, the lowest point position of the first through hole 21a is lower or higher than the lowest point position of the second through hole 21b. May be. When the lowest point position of the first through hole 21a is located higher than the lowest point position of the second through hole 21b, the difference in height of the lowest point position is the first shaft portion 20a and the second shaft part 20a. It is set to be equal to or less than the difference in the shaft diameter of the shaft portion 20b. In this way, the effect of increasing the distance between the grip member 21 and the intermediate transfer belt 17 can be obtained. In this embodiment, the case where the intermediate transfer belt 17 is disposed below the shaft member 20 has been described as an example, but the present invention is not limited to this. Let L1 be the closest distance between the first through hole 21a and the intermediate transfer belt 17 when the handle member 21 is stored in the storage portion 23a. The closest distance between the second through hole 21b and the intermediate transfer belt 17 is L2. Further, the difference between the shaft diameters of the first shaft portion 20a and the second shaft portion 20b is L3. At this time, if it is configured to satisfy L1 <L2 + L3, the distance between the handle member 21 and the intermediate transfer belt 17 can be increased.

  In the present embodiment, the shaft member 20 when carrying the intermediate transfer belt unit 10 has a rotational phase in which the flat portion 20c is substantially parallel to the direction of gravity. That is, when the phase of the shaft member 20 is a phase corresponding to the second state (the state where the intermediate transfer belt 17 and all the photosensitive drums are separated), the angle formed by the flat surface portion 20c and the gravitational direction is within 20 °. Is set to That is, when the phase of the shaft member 20 is a phase when the intermediate transfer belt unit 10 is detachable from the apparatus main body, the angle formed by the flat surface portion 20c and the gravitational direction is set within 20 °. More preferably, when the phase of the shaft member 20 is a phase when the intermediate transfer belt unit 10 is detachable from the apparatus main body, the angle formed by the flat surface portion 20c and the gravitational direction is set within 10 °. . The load due to the weight of the intermediate transfer unit 10 applied to the shaft member 20 via the handle member 21 is substantially upward in the gravitational direction. Thereby, the cross-sectional secondary moment with respect to the bending of the place where the load is applied to the shaft member 20 becomes relatively large, and the reduction of the allowable force against deformation and fracture is suppressed.

  According to the present embodiment, the shaft member 20 and the handle member are located at positions where the positions of the protrusion 21c provided in the through hole of the handle member 21 and the D-cut portion 20d provided on the shaft member 20 are shifted in the axial direction. 21 is assembled. By carrying out like this, after attaching the handle member 21, it can suppress that the shaft member 20 remove | deviates from the 1st through-hole 21a, and moves to the 2nd through-hole 21b. Moreover, since it does not require a new component in order to suppress that the shaft member 20 remove | deviates from the 1st through-hole 21a, and moves to the 2nd through-hole 21b, it can suppress the increase in a number of parts. it can.

<Reference example>
Here, as a reference example, FIGS. 13 to 15 show a configuration in which a separate fixing member is provided so that the fitting between the first shaft portion 20a and the first through hole 21a is not removed and the handle member is thrust-positioned. Use and explain. FIG. 13 is a schematic perspective view of the handle member 221. FIG. 14A is a schematic perspective view of a state in which the handle member 221 is assembled to the shaft member 220. FIG. 8B is a schematic cross-sectional view of the handle member 221 engaging portion in the state of FIG. FIG. 15A is a schematic perspective view showing a state where the second shaft portion 220b passes through the second through hole 221b during assembly. FIG. 15B is a schematic perspective view showing a state where the first shaft portion 220a passes through the second through hole 221b. FIG. 15C is a schematic perspective view showing a state when the first shaft portion 220a moves to the first through hole 221a and the fixing member 222 is assembled.

  The shaft member 220 includes a first shaft portion 220a at a position where the handle member 221 engages in the axial direction of the shaft member 220, and a second shaft portion 220b at other positions, and the outer diameter of the first shaft portion 220a. Is smaller than the outer diameter of the second shaft portion 220b. The handle member 221 is provided with a through hole through which the shaft member 220 passes, and the through hole has a first through hole 221a and a second shaft portion 220b having a width that fits the first shaft portion 220a of the shaft member 220. Is provided with a second through hole 221b. The first through hole 221a and the second through hole 221b are connected so that the first shaft part 220a can move between them. Further, the handle member 221 is provided with fixing member engaging portions 221c and 221d with which the fixing member 222 is engaged. When the fixing member 222 is engaged with the handle member 221, the first through hole 221 a and the second through hole 221 b are partitioned by the fixing member 222, and are surrounded by the first through hole 221 a and the fixing member 222. The through hole has a size with which the first shaft portion 220a is fitted (see FIGS. 13 and 14).

  Next, assembly of the shaft member 220 and the handle member 221 will be described. First, the second shaft portion 220b of the shaft member 220 is passed through the second through hole 221b of the handle member 221 in the axial direction (see FIG. 15A). When the second shaft portion 220b passes through the second through hole 221b in the axial direction, the first shaft portion 220a passes through the second through hole 221b (see FIG. 15B). In a state where the first shaft portion 220a passes through the second through hole 221b, the first shaft portion 220a moves from the second through hole 221b to the first through hole 221a. Here, when the fixing member 222 is assembled to the fixing member engaging portions 221c and 221d of the handle member 221, the first shaft portion 220a is fitted in the through hole surrounded by the first through hole 221a and the fixing member 222. (See FIGS. 14 and 15 (c)). Thereby, the grip member 221 is positioned in the radial direction with respect to the shaft member 220, and can be rotated about the shaft member 220 as a rotation center. Further, since the outer shape of the handle member 221 can be reduced by the difference in outer diameter between the first shaft portion 220a and the second shaft portion 220b and the handle member 221 can be separated from the belt member, the size of the unit can be reduced without impairing the function. And operability.

  However, the above-described configuration requires a fixing member 222 for positioning in addition to the shaft member 220 and the handle member 221, and there is a problem that the number of parts increases and the cost increases.

[Example 2]
The shape of the through hole of the handle member 21 is different from that of the first embodiment. This embodiment improves the assemblability of the handle member 21 with respect to the shaft member 20 in the first embodiment. The configuration of this embodiment will be described in detail with reference to FIGS.

  FIG. 11 is a schematic perspective view of the handle member 21 in the present embodiment. FIG. 12A is a schematic perspective view showing a state in which the first shaft portion 20a has moved to the first through hole 21a, and FIG. 12B shows the engagement of the handle member 21 in the state of FIG. It is a schematic sectional drawing of a part.

  The handle member 21 is provided with a through hole in the axial direction of the shaft member 20, and the through hole has a first through hole 21 a having a width that fits the first shaft portion 20 a of the shaft member 20 (first And a second through hole 21b (second shape part) through which the second shaft part 20b can pass. A protrusion 21c is provided between the first through hole 21a and the second through hole 21b. The through hole surrounded by the first through hole 21a and the protrusion 21c has a size that allows the first shaft portion 20a to be fitted.

  The protrusion 21c has a width in the axial direction of the shaft member 20 that is smaller than the groove width of the D-cut portion 20d. A protruding portion 21f is provided on the opposite surface side of the protruding portion 21c, and the distance of the gap H3 formed by the protruding portion 21c and the protruding portion 21f is the thickness between the flat surface portion 20c and the outer diameter portion of the first shaft portion 20a. The relationship is smaller than H2 (see FIG. 11).

  In assembling the handle member 21 to the shaft member 20, when the first shaft portion 20a moves from the second through hole 21b to the first through hole 21a, the D-cut portion 20d is formed by the protrusion portion 21c and the protrusion portion 21f. It passes through the formed gap H3. Therefore, the first shaft portion 20a is temporarily fixed in the first through hole 21a by the protrusion 21f. Thereby, it is suppressed that the 1st axial part 20a moves to the direction which returns to the 2nd through-hole 21b from the 1st through-hole 21a. Accordingly, when the first shaft portion 20a is passed through the first through hole 21a which is the next assembling operation, the side surface portion formed perpendicular to the flat surface portion 21c of the D-cut portion 21d is the projection portion 21c. It can suppress that it contacts the side surface of this and becomes an obstacle of work. For this reason, workability | operativity improves (refer FIG. 12).

  In the present embodiment, the distance of the gap H1 formed by the first through hole 21a and the protruding portion 21c is larger than the thickness H2 between the flat surface portion 20c and the outer diameter portion of the first shaft portion 20a. However, the present invention is not limited to this. Even if the gap H1 has a smaller relationship than the thickness H2, it is sufficient that the D-cut portion 21d can move within the gap H1. For example, if the difference between the gap H1 and the thickness H2 is 1 mm or less, the D-cut portion 21d can move the gap H1.

  In the present embodiment, the first shaft portion 20a and the second shaft portion have a circular cross section as an example, but the present invention is not necessarily limited thereto. For example, the cross section orthogonal to the axis may be elliptical.

10 Intermediate transfer belt unit 11 Secondary transfer inner roller 12 Steering roller (drive roller)
13 Tension roller 14 Auxiliary roller 15 Idler rollers 16a to 16d Primary transfer roller 17 Intermediate transfer belt 20 Shaft member 20a First shaft portion 20b Second shaft portion 20c Planar portion 20d D cut portion 21 Handle member 21a First penetration Hole 21b Second through hole 21c Protruding part 21d, 21e Side face part 21f Protruding part 100 Image forming apparatus 200 Belt circumferential direction 220 Shaft member 220a First shaft part 220b Second shaft part 221 Handle member 221a First through hole 221b Second through hole 221c Fixing member engaging part 221d Fixing member engaging part 222 Fixing member H1 A gap between the first through hole and the protruding part 21c H2 Thickness between the flat part and the outer diameter part of the first shaft part H3 The gap formed by the protrusion 21c and the protrusion 21f

Claims (8)

An image carrier for carrying an image;
A belt unit including a belt that is detachably provided in the apparatus main body and onto which a toner image carried by the image carrier is transferred;
A handle portion provided rotatably on the belt unit, for gripping the belt unit when the belt unit is removed from the apparatus main body;
An image forming apparatus comprising: a shaft provided in the belt unit and inserted into a through hole provided in the handle portion and rotatably supporting the handle portion;
The shaft includes a first shaft portion and a second shaft portion thicker than the first shaft portion,
The through hole is provided at a position different from the first hole portion with respect to a first hole portion into which the first shaft portion can be fitted and a direction orthogonal to the axial direction of the shaft, and the second shaft A second hole part into which the part can be inserted, and a communication part for communicating the first hole part and the second hole part,
The grip portion is provided at a position facing the first shaft portion when the handle unit is attached to the belt unit, and the gap of the communication portion is narrower than the outer diameter of the first shaft portion. Protruding from the inner surface of the through hole,
The shaft includes a third shaft portion whose thickness in a predetermined direction orthogonal to the axial direction of the shaft is smaller than that of the first shaft portion, and whose length in the axial direction of the shaft is longer than that of the protruding portion, When the third shaft portion is at a position facing the protrusion, the shaft is configured to pass through the communication portion.
An image forming apparatus.   The difference between the gap formed in the communication portion by the protrusion and the shaft diameter of the first shaft portion is larger than 1.5 mm and smaller than 2.5 mm. The image forming apparatus described.   3. The image forming apparatus according to claim 1, wherein a gap H <b> 1 formed in the communication portion by the protrusion is larger than a thickness H <b> 2 of the third shaft portion in the predetermined direction.   The belt and the image carrier can be contacted and separated by rotating the shaft, the third shaft portion includes a plane portion parallel to the axial direction of the shaft, and the axis of the shaft. And when the phase of the shaft is in a phase that allows the belt unit to be attached to and detached from the apparatus main body, the angle formed by the plane portion and the gravitational direction is within 20 °. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.   5. The apparatus according to claim 1, further comprising an opening provided on a side surface orthogonal to the axial direction of the image carrier, wherein the belt unit is detachably provided from the apparatus main body through the opening. The image forming apparatus according to claim 1.   The said handle | steering-wheel part is provided in the position which overlaps with a belt when it sees from the direction orthogonal to the axial direction of the said axis | shaft above the perpendicular direction of the said belt. The image forming apparatus described in 1.   In the cross section perpendicular to the axial direction, the closest distance between the first hole and the belt is L1, the closest distance between the second hole and the belt is L2, and the first shaft is The image forming apparatus according to claim 1, wherein L1 <L2 + L3 is satisfied, where L3 is a difference in outer diameter of the second shaft portion.   8. The axial direction of the shaft, wherein the first shaft portion and the third shaft portion are provided at a position sandwiched between the second shaft portions. The image forming apparatus according to claim 1.

Images