JP2017110748A - Screw mounting mechanism and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent falling of a screw in removing a mounting member from a mounted member without spending costs.SOLUTION: A screw mounting mechanism 30 of a printer 1 has a printer body 2 as a mounted member provided with a screw hole 33, a screw 31 engaged with the screw hole 33, a rear cover 5 of the mounting member having a fastening portion 34 recessed toward the screw hole 33, and a screw falling prevention member 32 capable of being fitted to the fastening portion 34. The fastening portion 34 has an insertion hole 35 capable of inserting a barrel portion 31b of the screw 31 at a position opposed to the screw hole 33. The rear cover 5 is mounted onto the printer body 2 by fastening the screw 31 to the screw hole 33 through the insertion hole 35. The screw falling prevention member 32 has a first opening portion 37 opposed to the insertion hole 35, and an internal space S communicated to the first opening portion 37 so that the screw 31 can be inserted, with an inner diameter larger than an outer diameter of a head portion 31a of the screw 31, and fitted to the fastening portion 34 in a state of inserting the screw 31 into the internal space S.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a screw attachment mechanism for attaching an attachment member such as a cover to a member to be attached such as an apparatus main body with a screw, and an image forming apparatus provided with the screw attachment mechanism.

  Some image forming apparatuses and other apparatuses are configured to cover the apparatus main body with a cover. For example, the main body of the image forming apparatus includes a control unit on which a replacement unit such as a toner container, a processing unit such as an image forming unit, and a CPU and a memory for controlling various processes such as image formation are mounted. Is done. Since it is necessary to remove the cover during installation of the image forming apparatus, optional setup, or maintenance of each unit or control board, the cover is detachably attached to the apparatus main body.

  Attachment members such as covers are attached to the attachment members such as the device body with screws (screws). When removing the screws, the screws must be dropped and lost or dropped into the machine. There is. In such a case, the worker needs to find a screw or remove the screw that has entered the machine. Therefore, a screw attachment mechanism that avoids the screw from being lost due to being detached from an attachment member such as a cover may be provided.

  For example, in Patent Document 1, in an image forming apparatus, an apparatus attachment device (attachment member) that enables an optional product to be attached later is attached to an apparatus main body (attachment member) that is an attachment device. A hand screw is used to connect the main body of the device and optional items. The hand screw passes through the optional cover, and a compression spring is arranged between the cover and the retainer so that the hand screw can penetrate and extend in the axial direction.

JP 2012-42893 A

  However, in the image forming apparatus as described above, a special screw provided with a straight portion between the head portion of the screw and the male screw portion of the body portion is provided with a compression spring and a stopper (washer) for the screw. Is required. And after passing a screw through attachment members, such as a cover, a screw is prevented from dropping from an attachment member by fitting a washer in the straight part of a screw. Further, in order to secure a space for arranging the compression spring and the washer, it is necessary to provide a predetermined gap between the attachment member such as the cover and the attachment member such as the apparatus main body. Further, in order to provide the straight portion as described above, or to connect the mounting member and the mounted member with a predetermined gap, it is necessary to prepare a longer special screw. The special screw as described above is expensive as compared with a normal screw.

  In view of the above circumstances, an object of the present invention is to prevent the screw from dropping when the mounting member is removed from the mounted member without incurring costs.

  The screw mounting mechanism of the present invention includes a mounted member in which a screw hole is screwed, a screw that is screwed into the screw hole, a mounting member that has a fastening portion that is recessed toward the screw hole, and the fastening A screw fall prevention member that can be fitted to a portion, and the fastening portion has an insertion hole through which the barrel portion of the screw can be inserted at a position facing the screw hole, and the attachment member includes the screw Is fastened to the screw hole through the insertion hole, and is attached to the attached member, and the screw drop prevention member includes a first opening facing the insertion hole, and the first opening An internal space communicating with the opening and into which the screw can be inserted, wherein the first opening and the internal space have an inner diameter larger than an outer diameter of the head of the screw. The screw is fitted into the fastening portion with the screw inserted into the internal space.

  The image forming apparatus of the present invention includes the above-described screw attachment mechanism, the apparatus main body as the attached member, and the cover as the attachment member detachably attached to the apparatus main body.

  According to the present invention, it is possible to prevent the screw from dropping when the mounting member is removed from the mounted member without incurring costs.

1 is a perspective view showing a printer according to an embodiment of the present invention from the front side. 1 is a perspective view showing a printer according to an embodiment of the present invention from the rear side. 1 is a cross-sectional view illustrating an outline of a printer according to an embodiment of the present invention. It is a perspective view which shows the screw attachment mechanism of the printer which concerns on one Embodiment of this invention from back. FIG. 4 is a cross-sectional view showing a state where screws are attached in the screw attachment mechanism of the printer according to the embodiment of the present invention. FIG. 5 is a cross-sectional view illustrating a state where a screw is removed in the screw mounting mechanism of the printer according to the embodiment of the present invention. It is a perspective view which shows the screw fall prevention member in the screw attachment mechanism of the printer which concerns on one Embodiment of this invention from back. It is a perspective view which shows the screw fall prevention member in the screw attachment mechanism of the printer which concerns on one Embodiment of this invention from the front.

  First, an overall configuration of a printer 1 (image forming apparatus) according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing the printer 1 from the front side, FIG. 2 is a perspective view showing the printer 1 from the rear side, and FIG. 3 is a cross-sectional view showing the outline of the printer 1. An arrow Fr attached to each figure indicates the front side (front side) of the printer 1. The right side in FIG. 1 is the front side (front side) of the printer 1.

  As shown in FIGS. 1 to 3, the printer 1 includes a box-shaped printer main body 2 (apparatus main body). A paper feed cassette 3 for storing paper (recording medium) is detachably provided in the lower part of the printer main body 2, and a paper discharge tray 4 is provided in the upper part of the printer main body 2. As shown in FIG. 2, a rear cover 5 is detachably attached to the back side of the printer main body 2.

  As shown in FIG. 3, in the printer main body 2, an exposure unit 7 composed of a laser scanning unit (LSU) is arranged at the front, and an image forming unit 8 is provided at the rear. A photosensitive drum 10 (image carrier) is rotatably provided in the image forming unit 8. Around the photosensitive drum 10, a charger 11 and a developing device 13 connected to a toner container 12 are provided. The transfer roller 14 and the cleaning device 15 are arranged along the rotation direction of the photosensitive drum 10 (see the arrow X in FIG. 1).

  Further, inside the printer main body 2, a sheet conveyance path 16 is provided at the rear of the image forming unit 8 from below to above. A paper feed unit 17 is provided at the upstream end of the conveyance path 16, and a transfer unit 18 constituted by the photosensitive drum 10 and the transfer roller 14 is provided at a midstream part of the conveyance path 16, and a downstream part of the conveyance path 16. Is provided with a fixing device 20. A reverse path 21 for double-sided printing is provided on the rear side of the transport path 16.

  In addition, a control unit 22 is provided inside the printer main body 2 in order to perform overall control of each constituent member and each process of the printer 1. For example, the control unit 22 is configured by mounting a CPU, a memory, and other electronic components on a control board (not shown).

  Each component inside the printer main body 2 (exposure unit 7, image forming unit 8, conveyance path 16, paper feeding unit 17, transfer unit 18, fixing device 20, reversing path 21, control unit 22, etc.) is, for example, When the rear cover 5 is removed from the printer main body 2, the rear cover 5 is exposed on the back side of the printer main body 2, so that maintenance or the like can be performed.

  Next, an image forming operation of the printer 1 having such a configuration will be described. When image data is input from a computer or the like connected to the printer 1 and an instruction to start printing is given, the control unit 22 executes an image forming operation as follows.

  First, after the surface of the photosensitive drum 10 is charged by the charger 11, exposure corresponding to image data is performed on the photosensitive drum 10 by laser light from the exposure device 7 (see arrow P in FIG. 3). Then, an electrostatic latent image is formed on the surface of the photosensitive drum 10. Next, the developing device 13 develops the electrostatic latent image into a toner image with the toner supplied from the toner container 12.

  On the other hand, the sheet taken out from the sheet feeding cassette 3 by the sheet feeding unit 17 is conveyed to the transfer unit 18 in synchronization with the above-described image forming operation, and the toner image on the photosensitive drum 10 is transferred to the sheet by the transfer unit 18. Is transcribed. The sheet on which the toner image has been transferred is conveyed downstream in the conveyance path 16 and enters the fixing device 20, where the toner image is fixed on the sheet. The sheet on which the toner image is fixed is discharged from the downstream end of the conveyance path 16 to the discharge tray 4. The toner remaining on the photosensitive drum 10 is collected by the cleaning device 15.

  Next, the screw attachment mechanism 30 provided in the printer 1 will be described with reference to FIGS. As shown in FIG. 4, the screw attachment mechanism 30 is a mechanism for attaching the rear cover 5 as an attachment member to the printer main body 2 as an attachment member with a screw 31, and particularly includes a screw drop prevention member 32.

  At least one screw hole 33 is provided on the back side of the printer body 2, and a female screw is formed (screwed) on the inner periphery of the screw hole 33. The positions of the screw holes 33 are not particularly limited. In order to fix the rear cover 5 to the back side of the printer main body 2 with the screws 31, the minimum number of screw holes 33 is balanced on the back side of the printer main body 2. It only has to be arranged.

  As shown in FIGS. 4 to 6, the rear cover 5 is provided with a fastening portion 34 at a position corresponding to each screw hole 33 of the printer body 2. The fastening portion 34 is recessed toward the corresponding screw hole 33, that is, forward, and the inner diameter of the recessed portion of the fastening portion 34 is larger than the outer diameter of the screw drop prevention member 32, and the screw hole 33 (front). The diameter is reduced toward.

  The fastening portion 34 is formed with an insertion hole 35 through which the body portion 31b of the screw 31 can be inserted at a position facing the screw hole 33 on the bottom surface of the concave portion. At the front portion of the fastening portion 34, at least one engagement hole 36 that is recessed from the inner peripheral side toward the outer radial direction is provided at a predetermined position in the circumferential direction. For example, in the present embodiment, the three engagement holes 36 are formed to penetrate in the outer diameter direction at three positions that are equally spaced in the circumferential direction. In addition, although the engagement hole 36 of this embodiment has penetrated ahead as well as the outer diameter direction, the front portion of the engagement hole 36 may be closed.

  A screw 31 applied to the screw attachment mechanism 30 includes a head portion 31a and a body portion 31b, and a male screw that is screwed into the screw hole 33 of the printer body 2 is formed on the peripheral surface of the body portion 31b. . The head 31a of the screw 31 has an operated shape such as a cross hole for rotating the screw 31, and is operated by a tool such as a screwdriver. In the present embodiment, the screw 31 is formed with a flange 31c along the outer periphery of the head portion 31a, and the inner diameter side portion of the screw 31 of the head portion 31a is the second opening of the screw drop prevention member 32 described below. 38, the screw 31 may be formed without providing the flange 31c on the head 31a.

  In the screw attachment mechanism 30 as described above, the screw 31 is fastened to the screw hole 33 of the printer main body 2 via the insertion hole 35 of the fastening portion 34 of the rear cover 5, so that the rear cover 5 is attached to the printer main body 2. It will be in the state.

  As shown in FIGS. 5 to 8, the screw drop prevention member 32 has an internal space S in which the head portion 31 a of the screw 31 can move in the axial direction of the screw 31, that is, an internal space S in which the screw 31 can be inserted. It is formed in a cylindrical shape. FIG. 5 shows a state where the screw 31 is moved forward in the internal space of the screw drop prevention member 32 when the screw 31 is fastened to the screw hole 33, and in FIG. 6, when the screw 31 is removed from the screw hole 33. The state which moved back in the internal space of the screw fall prevention member 32 is shown. The screw drop prevention member 32 has an outer shape that can be fitted in the recess of the fastening portion 34 of the rear cover 5, and is fitted to the fastening portion 34 with the screw 31 inserted into the internal space S. The screw drop prevention member 32 is configured to be detachable from the fastening portion 34.

  The screw fall prevention member 32 includes a first opening 37 that faces the insertion hole 35 in a state of being inserted into the fastening portion 34, and a second opening into which a tool such as a screwdriver that operates the head 31 a of the screw 31 can be inserted. 38. The screw drop prevention member 32 is configured such that the first opening 37 and the second opening 38 communicate with each other through the internal space S, and the internal space S is shorter than the entire length of the screw 31 in the axial direction of the screw 31. It is formed to have a length. A first opening 37 formed with an area into which the head portion 31a of the screw 31 can be inserted, and a tool such as a screwdriver for operating the head portion 31a of the screw 31 can be inserted, with a smaller area than the head portion 31a of the screw 31. And a second opening 38 formed. The first opening 37 is formed at the front end of the screw drop prevention member 32 in the axial direction of the screw 31 and has an inner diameter larger than the outer diameter of the head 31 a of the screw 31. The second opening 38 is formed near the center of the screw drop prevention member 32 in the axial direction of the screw 31 and has an inner diameter smaller than the outer diameter of the head 31 a of the screw 31.

  The screw drop prevention member 32 includes at least one engagement claw 40 at the front end (the end where the first opening 37 is provided). Each engagement claw 40 is formed to be able to engage with each engagement hole 36 at a position corresponding to each engagement hole 36 of the fastening portion 34 of the rear cover 5 on the outer periphery of the front end portion of the screw drop prevention member 32. The The engagement state between each engagement claw 40 and each engagement hole 36 is, for example, that each engagement claw 40 is pushed out from the outer peripheral side of the fastening portion 34 of the rear cover 5 via each engagement hole 36. Can be easily released.

  Further, the screw drop prevention member 32 is provided with a tool such as a screwdriver for operating the head 31a of the screw 31 at the second end 38 at the rear end (the end opposite to the first opening 37) in the axial direction. A tool guide 41 for guiding to the side is provided. The tool guide 41 is formed of, for example, an inner peripheral surface of the rear end portion of the screw drop prevention member 32 and is formed in a mortar shape having a diameter reduced from the rear side to the second opening 38.

  Further, one or more projecting portions 42 projecting in the outer diameter direction are formed at predetermined positions in the circumferential direction on the outer periphery of the rear end portion of the screw drop preventing member 32. Each protrusion 42 is provided, for example, at a position that is symmetrical to each engagement claw 40 when viewed from the center of the outer periphery of the screw drop prevention member 32. Each protrusion 42 abuts against the inner peripheral surface of the fastening portion 34 in a state where the screw drop prevention member 32 is fitted to the fastening portion 34 of the rear cover 5.

  In the screw mounting mechanism 30 as described above, the screw drop prevention member 32 is inserted in the internal space S and the body portion 31b of the screw 31 is inserted into the insertion hole 35 of the fastening portion 34 of the rear cover 5. The first opening 37 is fitted to the fastening portion 34 so as to face the insertion hole 35.

  According to the present embodiment, as described above, the screw attachment mechanism 30 applied to the printer 1 includes the printer main body 2 as the attached member in which the screw hole 33 is screwed, and the screw that is screwed into the screw hole 33. 31, a rear cover 5 as an attachment member having a fastening portion 34 recessed toward the screw hole 33, and a screw drop prevention member 32 that can be fitted to the fastening portion 34. And the fastening part 34 has the insertion hole 35 which can penetrate the trunk | drum 31b of the screw 31 in the position facing the screw hole 33. As shown in FIG. The rear cover 5 is attached to the printer main body 2 when the screw 31 is fastened to the screw hole 33 via the insertion hole 35. The screw fall prevention member 32 has a first opening 37 that faces the insertion hole 35 and an internal space S that communicates with the first opening 37 and into which the screw 31 can be inserted. The screw drop prevention member 32 is formed so that the first opening 37 and the internal space S have an inner diameter larger than the outer diameter of the head 31 a of the screw 31. The screw drop prevention member 32 is fitted into the fastening portion 34 with the screw 31 inserted into the internal space S.

  As a result, the screw drop prevention member 32 is attached to the fastening portion 34 of the rear cover 5 in a state of including the screw 31, and the screw 31 is disposed between the rear cover 5 and the screw drop prevention member 32. The screw 31 removed from the screw hole 33 of the main body 2 can be prevented from falling. In addition, since the screw 31 can be prevented from dropping simply by providing the screw drop prevention member 32, it is not necessary to prepare a special screw, and the cost of the screw 31 can be reduced. That is, the screw 31 can be prevented from dropping when the rear cover 5 is removed from the printer body 2 without incurring costs.

  Moreover, according to this embodiment, the screw fall prevention member 32 has the 2nd opening part 38 which can insert the tool which operates the head 31a of the screw 31. FIG. The screw drop prevention member 32 has a second opening 38 having an inner diameter smaller than the outer diameter of the head 31a of the screw 31 and an inner space S having a length shorter than the entire length of the screw 31 in the axial direction. Is formed. The screw drop prevention member 32 is fitted to the fastening portion 34 in a state where the body portion 31 b of the screw 31 is inserted into the insertion hole 35.

  As a result, the screw 31 can be moved within the range of the internal space S of the screw drop prevention member 32, so that the screw drop prevention member 32 can be inserted into the screw drop prevention member 32 even when it is attached to the fastening portion 34 of the rear cover 5. The screw 31 can be fastened or removed from the screw hole 33 of the printer main body 2 through the second opening 38. Further, since the internal space S of the screw drop prevention member 32 is shorter than the entire length of the screw 31, the tip of the body portion 31b of the screw 31 in the internal space S of the screw drop prevention member 32 attached to the fastening portion 34 is It is always in a state of being inserted through the insertion hole 35 of the fastening portion 34. Therefore, it is not necessary to align the screw 31 with respect to the screw hole 33, and the screw 31 can be easily fastened to the screw hole 33.

  Furthermore, according to the present embodiment, the second opening 38 is provided near the center of the screw drop prevention member 32 in the axial direction. The screw drop prevention member 32 includes a tool guide 41 that guides the tool to the second opening 38 at the rear end (the end opposite to the first opening 37) in the axial direction.

  Thereby, even when the screw 31 is included in the screw drop prevention member 32, a tool such as a screwdriver handled by the operator is guided to the head 31 a of the screw 31 through the second opening 38 by the tool guide 41. Therefore, the operator can easily operate the screw 31 without visually observing it.

  Further, according to the present embodiment, the screw drop preventing member 32 is configured to be detachable from the fastening portion 34.

  Thereby, even if damage such as deformation of the screw 31 or a missing part occurs, only the screw 31 needs to be replaced, and the screw drop prevention member 32 can be reused. Further, when the rear cover 5 is removed from the printer main body 2, the screw drop prevention member 32 can be attached to the fastening portion 34, and when the rear cover 5 is attached to the printer main body 2, the screw fall prevention member 32 can be removed from the fastening portion 34. . Even when the operator removes the rear cover 5 to which the screw drop prevention member 32 is not attached in advance, the operator can use the screw fall prevention member 32 prepared separately. Therefore, it is not necessary to provide the screw drop prevention member 32 for each printer 1, and it is sufficient that the operator prepares the screw drop prevention member 32.

  Furthermore, according to the present embodiment, the screw drop prevention member 32 includes the engaging claw 40 at the front end (the end where the first opening 37 is provided), and the fastening portion 34 engages with the engaging claw 40. Possible engagement holes 36 are provided.

  Thereby, the structure which can attach or detach the screw fall prevention member 32 is easily realizable.

  In the present embodiment, the configuration in which the fastening portion 34 of the rear cover 5 and the screw drop prevention member 32 are formed in a cylindrical shape has been described, but the present invention is not limited to this configuration. The screw drop prevention member 32 only needs to be configured to be able to move the screw 31 in the internal space S. For example, in another embodiment, the fastening portion 34 of the rear cover 5 and the screw drop prevention member 32 have a rectangular cylindrical shape. It may be formed.

  Further, in the present embodiment, the configuration in which the fastening portion 34 of the rear cover 5 is provided with the three engagement holes 36 and the screw fall prevention member 32 is provided with the three engagement claws 40 has been described, but the configuration is not limited thereto. . For example, in another embodiment, one or two engagement holes 36 may be provided in the fastening portion 34 of the rear cover 5, and one or two engagement claws 40 may be provided in the screw drop prevention member 32. Alternatively, four or more engagement holes 36 may be provided in the fastening portion 34 of the rear cover 5, and four or more engagement claws 40 may be provided in the screw drop prevention member 32.

  In the present embodiment, the case where the configuration of the present invention is applied to the printer 1 has been described. However, in other different embodiments, other image forming apparatuses such as a copying machine, a facsimile, a multifunction peripheral, or a member to be attached are used. It is also possible to apply the configuration of the present invention to other devices for attaching the attachment member with screws.

1 Printer (image forming device)
2 Printer body (attachment member)
5 Rear cover (mounting member)
DESCRIPTION OF SYMBOLS 8 Image formation part 22 Control part 30 Screw attachment mechanism 31 Screw 31a Head part 31b Body part 32 Screw fall prevention member 33 Screw hole 34 Fastening part 35 Insertion hole 36 Engagement hole 37 1st opening part 38 2nd opening part 40 Engagement Claw 41 Tool guide 42 Projection

Claims (6)

A to-be-attached member with screw holes;
A screw screwed into the screw hole;
An attachment member having a fastening portion recessed toward the screw hole;
A screw drop prevention member that can be fitted to the fastening portion,
The fastening portion has an insertion hole through which the body of the screw can be inserted at a position facing the screw hole,
The attachment member is in a state of being attached to the attached member by fastening the screw to the screw hole through the insertion hole,
The screw fall prevention member has a first opening facing the insertion hole, and an internal space that is in communication with the first opening and into which the screw can be inserted. The first opening and the internal A screw mounting mechanism, wherein the space is formed to have an inner diameter larger than the outer diameter of the head of the screw, and is fitted to the fastening portion in a state where the screw is inserted into the inner space. .   The screw fall prevention member has a second opening into which a tool for operating the head of the screw can be inserted, and the second opening has an inner diameter smaller than an outer diameter of the screw head, The internal space is formed so as to have a length shorter than the entire length of the screw in the axial direction, and the body portion of the screw is inserted into the insertion hole and is fitted into the fastening portion. The screw mounting mechanism according to claim 1. The second opening is provided near the center of the screw drop prevention member in the axial direction,
The screw drop prevention member includes a tool guide that guides the tool to the second opening at an end opposite to the first opening in the axial direction. Screw mounting mechanism as described.   The screw attachment mechanism according to any one of claims 1 to 3, wherein the screw fall prevention member is configured to be detachable from the fastening portion. The screw fall prevention member includes an engaging claw at an end where the first opening is provided,
The screw attachment mechanism according to claim 4, wherein the fastening portion includes an engagement hole engageable with the engagement claw. The screw mounting mechanism according to any one of claims 1 to 5,
An apparatus main body as the attached member;
An image forming apparatus comprising: a cover as the attachment member that is detachably attached to the apparatus main body.

Images