Image-forming device

Abstract

This imaging-forming device is provided with a restricting mechanism that restricts the movement of a pin (59) in an imaging unit within a slotted hole (15) in a console. The restricting mechanism is provided with: a pressing lever (83) that is turnable from a state of abutting on the pin (59) in the slotted hole (15), in a direction of parting away from the slotted hole (15); an opening / closing lever (85) that turns attendant on the operation of closing a cover (7); and an elastic member (87) that is disposed between the pressing lever (83) and the opening / closing lever (85) in an elastically deformed state and that applies a load on the pressing lever (83) in a direction opposite from the parting-away direction. When the cover (7) is open, the elastic member (87) applies a first load to the pressing lever (53), and when the cover (7) is shut, the opening / closing lever (85) turns to further elastically deform the elastic member (87), applying a second load greater than the first load on the pressing lever (85).

Description

Image forming device

[0001] The present invention relates to an image forming apparatus having a removable imaging unit.

[0002] In an image forming apparatus, an imaging unit is mounted at a predetermined position within a housing, and is provided so as to be removable from the housing for maintenance or the like.

[0003] For example, Patent Document 1 discloses an image forming device that supports a process cartridge (corresponding to an imaging unit) and has a support member that is movable between an inner position located inside the device main body (corresponding to a housing) and an outer position located outside the device main body.

[0004] Japanese Patent Application Laid-Open No. 2016-035587

[0005] In an image forming apparatus having the above-described configuration, if the process cartridge located in the inner position is misaligned, the toner image transferred to the intermediate transfer belt may be misaligned, resulting in poor image quality. Therefore, it is necessary to position the process cartridge in the apparatus body without any rattle.

[0006] SUMMARY OF THE INVENTION In consideration of the above circumstances, an object of the present invention is to provide an image forming apparatus that can reliably prevent misalignment of an imaging unit.

[0007] According to one aspect of the present invention, there is provided an image forming apparatus comprising: a housing having an opening on a side surface; a cover capable of opening and closing the opening; an imaging unit disposed within the housing and capable of being pulled out through the opening in a predetermined pulling direction; a notch formed in a side edge of the opening along the pulling direction; a pin provided in the imaging unit and abutting against the inner end of the notch to position the imaging unit in the housing; and a restricting mechanism restricting movement of the pin within the notch, the restricting mechanism being configured to restrict movement of the pin from a state in which the restricting mechanism abuts against the pin within the notch. a pressing lever that can rotate in a separating direction away from the pressing lever; an opening / closing lever that rotates in association with the closing operation of the cover; and an elastic member that is disposed between the pressing lever and the opening / closing lever in an elastically deformed state and applies a load to the pressing lever in a direction opposite to the separating direction, wherein when the cover is open, a first load is applied to the pressing lever by the elastic restoring force of the elastic member, and when the cover is closed, the opening / closing lever rotates to further elastically deform the elastic member, and a second load larger than the first load is applied to the pressing lever by the elastic restoring force of the elastic member.

[0008] According to the present invention, an appropriate load is applied to the pressure lever when the cover is closed and when it is open, so even if external forces such as vibrations or impacts are applied to the housing, the rotation of the pressure lever is restricted and inadvertent movement of the pin of the imaging unit can be prevented.

[0009] 1 is a side view schematically illustrating the internal configuration of an image forming apparatus according to an embodiment of the present invention; FIG. 2 is a perspective view illustrating a housing and an imaging unit of an image forming apparatus according to an embodiment of the present invention; FIG. 3 is a perspective view illustrating a pin of an imaging unit and a cutout hole of a housing in an image forming apparatus according to an embodiment of the present invention; FIG. 4 is a perspective view illustrating a cover of an image forming apparatus according to an embodiment of the present invention; FIG. 5 is a perspective view illustrating a restriction mechanism according to a first example in an image forming apparatus according to an embodiment of the present invention; FIG. 6 is a side view illustrating a restriction mechanism according to the first example in an image forming apparatus according to an embodiment of the present invention; FIG. 7 is a side view illustrating a restriction mechanism according to the first example in an image forming apparatus according to an embodiment of the present invention when the front cover is open; FIG. 8 is a side view illustrating a restriction mechanism according to the first example in an image forming apparatus according to an embodiment of the present invention when the front cover is in the middle of being closed in an image forming apparatus according to an embodiment of the present invention; FIG. 9 is a side view illustrating a restriction mechanism according to the first example in an image forming apparatus according to an embodiment of the present invention when the front cover is closed in an image forming apparatus according to an embodiment of the present invention; 1 is a perspective view showing a restriction mechanism in an image forming apparatus according to a second embodiment of the present invention; FIG. 2 is a side view showing the restriction mechanism according to the second embodiment when the front cover is open in an image forming apparatus according to an embodiment of the present invention; FIG. 3 is a side view showing the restriction mechanism according to the second embodiment when the front cover is in the middle of being closed in an image forming apparatus according to an embodiment of the present invention; and FIG. 4 is a side view showing the restriction mechanism according to the second embodiment when the front cover is closed in an image forming apparatus according to an embodiment of the present invention.

[0010] An image forming apparatus according to an embodiment of the present invention will be described below with reference to the drawings. In the following, rotational directions, left-right directions, and up-down directions may be indicated, but unless otherwise specified, these directions are shown as examples in each drawing.

[0011] First, a first embodiment of the image forming apparatus 1 will be described. The image forming apparatus 1 will be described with reference to FIGS. 1 to 4. FIG. 1 is a side view that schematically shows the internal configuration of the image forming apparatus 1, FIG. 2 is a perspective view that shows the housing 3 and the imaging unit 43 of the image forming apparatus 1, FIG. 3 is a perspective view that shows the pin 59 of the imaging unit 43 and the notched hole 15 of the housing 3, and FIG. 4 is a perspective view that shows the front cover 7. In each figure, Fr, Rr, L, and R indicate the front side, rear side, left side, and right side of the image forming apparatus 1, respectively.

[0012] As shown in Figure 2, the housing 3 of the image forming apparatus 1 has left and right side panels 3a that face each other in the left-right direction, a partition panel 3b that connects the left and right side panels 3a, and front and rear stays 3c. The partition panel 3b divides the space between the left and right side panels 3a into an upper space S1 and a lower space S2. The front and rear stays 3c are arranged in the upper space S1, spaced apart in the front-rear direction. An opening 5 facing forward in the upper space S1 corresponds to the opening of the present invention.

[0013] As shown in FIG. 1 , the opening 5 can be opened and closed by a front cover 7. The front cover 7 is an example of a cover capable of opening and closing an opening according to the present invention. As shown in FIG. 4 , the front cover 7 has a width wider than the opening 5 and a height greater than the opening 5. The left and right side edges and the upper edge of the front cover 7 are curved inward. Left and right regulating members 9 are provided on the left and right ends of the inner surface of the front cover 7 along the height direction of the front cover 7. The left and right regulating members 9 have elongated holes 9a formed along the longitudinal direction. The left and right regulating members 9 have semicircular support portions 9b formed on the lower ends thereof.

[0014] The front cover 7 is rotatably supported by the left and right side plates 3a. Cover rotation fulcrums 3d (see also FIG. 1) are provided on the left and right side plates 3a below the partition plate 3b. Left and right support portions 9b of the front cover 7 are rotatably supported by the cover rotation fulcrums 3d. The front cover 7 rotates between a closed position where it stands upright from the cover rotation fulcrums 3d to close the opening 5 and an open position where it rotates in a horizontal plane from the cover rotation fulcrum 3d to open the opening 5.

[0015] The front cover 7 is maintained in an open position by stoppers 11. One end of the stoppers 11 is rotatably supported on the left and right side plates 3a above the cover rotation fulcrum 3d, and the other end of the stoppers 11 is movably supported in the elongated holes 9a of the restricting member 9. The other end of the stoppers 11 is engaged with the end of the elongated holes 9a on the cover rotation fulcrum 3d side, thereby maintaining the front cover 7 in an open position. A protruding piece 13 is provided at the longitudinal center of the side surface of the stopper 11, protruding into the space of the housing 3 in a direction perpendicular to the longitudinal direction. The protruding piece 13 is shaped like a rectangular parallelepiped with a predetermined thickness in the left-right direction, and has an upper surface 13a, a tip surface 13b, and an inclined surface 13c at the corner between the upper surface 13a and the tip surface 13b (see also FIG. 6 ).

[0016] 2, notched holes 15 of a predetermined length are formed horizontally on the left and right side edges (left and right side plates 3a) of opening 5. Furthermore, pins 17 protruding from the inner surfaces are provided at the rear of the left and right side plates 3a. The pins 17 are provided at the same height as the notched holes 15.

[0017] Furthermore, on the left and right side edges (left and right side plates 3a) of the opening 5, there are provided restriction mechanisms 81 (see FIG. 1, not shown in FIG. 2) that press pins of an imaging unit (described later) against the inner ends of the notched holes 15. The restriction mechanisms 81 will be described later. The restriction mechanisms 81 are provided opposite the stoppers 11 at the respective positions where the stoppers 11 are provided.

[0018] Referring again to FIG. 1, a discharge tray 21 is provided on the top plate of the housing 3, and a sheet discharge opening 23 is provided behind the discharge tray 21.

[0019] The housing 3 is provided with a sheet feeding section 25, an electrophotographic image forming section 27, a fixing device 29, and a discharge device 31. The housing 3 also has a main sheet transport path 33 and a reversing path 35 extending from the lower space S2 to the upper space S1.

[0020] The sheet feeding unit 25 is disposed in the lower space S2 and includes a sheet feeding cassette 39 that stores sheets, and a sheet feeding device 41 that feeds sheets from the sheet feeding cassette 39 to the main transport path 33. The sheet feeding cassette 39 is detachable in the front-rear direction through an opening at the front of the lower space S2. The sheet feeding device 41 is disposed at the rear of the lower space S2.

[0021] The image forming section 27 includes an image forming unit 43, an intermediate transfer device 45, and an exposure device 47, which are arranged in the upper space S1.

[0022] The imaging unit 43 includes four individual units 51 corresponding to the four colors of toner (yellow, magenta, cyan, and black), and left and right unit frames 53 that support the four individual units 51. Each individual unit 51 includes a drum unit 55 including a photosensitive drum on which an electrostatic latent image is formed, and a developing unit 57 that develops the electrostatic latent image into a toner image using a single-component development method. The four individual units 51 are arranged side by side in the front-to-rear direction and are removably supported by the left and right unit frames 53.

[0023] The left and right unit frames 53 are formed with pins 59 and cutout holes 61. The pins 59 are formed at the front end portions of the outer surfaces of the left and right unit frames 53 so as to protrude outward. The cutout holes 61 are formed at the rear edges of the left and right unit frames 53 along the front-to-rear direction. The cutout holes 61 are formed at the same height as the pins 59.

[0024] The imaging unit 43 is positioned relative to the housing 3 by the pins 59 abutting against the rear ends (rear ends) of the notched holes 15 in the left and right side plates 3a (see FIG. 3 ) and the pins 17 in the left and right side plates 3a abutting against the front ends (front ends) of the notched holes 61. The imaging unit 43 can be pulled out forward through the opening 5. In this way, the pulling direction of the imaging unit 43 is the forward direction along the horizontal direction. When replacing the developing unit 57 after toner is consumed or when performing maintenance on the imaging unit 43, the imaging unit 43 is pulled out and removed from the housing 3.

[0025] The intermediate transfer device 45 includes an endless intermediate transfer belt 65, four primary transfer rollers 67 corresponding to the four individual units 51, and a secondary transfer roller 69. The intermediate transfer belt 65 is wound around a drive roller, a driven roller, and a tension roller that are spaced apart in the front-to-rear direction. The four primary transfer rollers 67 are arranged in a line in the front-to-rear direction in the hollow portion of the intermediate transfer belt 65. The secondary transfer roller 69 is arranged behind the intermediate transfer belt 65. A secondary transfer nip is formed between the intermediate transfer belt 65 and the secondary transfer roller 69.

[0026] The intermediate transfer device 45 is disposed below the imaging unit 43 and fixed to the partition plate 3b. Specifically, the height of the left and right unit frames 53 of the imaging unit 43 is higher than the height of the individual units 51, so that a predetermined space is formed between the unit frames 53 below the individual units 51. The intermediate transfer device 45 is disposed within this space. As shown in FIG. 1 , the four primary transfer rollers 67 of the intermediate transfer device 45 face the photosensitive drums of the drum units 55 of the four individual units 51 of the imaging unit across the intermediate transfer belt 65, forming primary transfer nips between the intermediate transfer belt 65 and the photosensitive drums. The exposure device 47 is supported by the front and rear stays 3c above the imaging unit 43.

[0027] The fixing device 29 has a pressure roller and a heating roller, and forms a fixing nip between the two rollers. As shown in Figure 1, the fixing device 29 is disposed above the secondary transfer nip. The discharge device 31 is disposed above the fixing device 29 and inside the discharge port 23.

[0028] The main transport path 33 is formed from the sheet feed device 41 of the sheet feed unit 25, passing through the secondary transfer nip and the fixing nip, toward the discharge device 31. A pair of registration rollers 71 is arranged between the sheet feed device 41 and the secondary transfer nip on the main transport path 33. The reversing path 35 branches off from the main transport path 33 downstream of the fixing device 29 in the sheet transport direction, and merges with the main transport path upstream of the pair of registration rollers 71.

[0029] Next, a brief description will be given of the image forming operation. In the image forming section 27, a toner image is formed on an individual unit 51 of the imaging unit 43 based on image data exposed by the exposure device 47. The toner image is transferred from the individual unit 51 to the intermediate transfer belt 65 at the primary transfer nip. As a result, a full-color toner image is formed on the intermediate transfer belt 65.

[0030] Meanwhile, in the sheet feeding unit 25, a sheet is transported from a paper feed cassette 39 to the main transport path 33 by the paper feed device 41. The sheet is transported to the secondary transfer nip at an appropriate timing by a pair of registration rollers 71. At the secondary transfer nip, a toner image formed on the intermediate transfer belt 65 is transferred to one side of the sheet. The sheet is transported along the main transport path 33 to the fixing device 29, where the toner image is fixed to the sheet at the fixing nip. The sheet is further transported to the discharge device 31, and is discharged by the discharge device 31 through the discharge port 23 onto the discharge tray 21.

[0031] In the case of double-sided printing, a sheet with a toner image fixed on one side is transported from the main transport path 33 to the reversal path 35, and the toner image is transferred to the other side of the sheet at the secondary transfer nip. After that, the toner image is fixed on the other side of the sheet by the fixing device 29, and the sheet is transported to the discharge device 31, and is discharged by the discharge device 31 through the discharge port 23 onto the discharge tray 21.

[0032] Next, the restriction mechanism 81 will be described with reference to Figures 5 and 6. Figure 5 is a perspective view showing the restriction mechanism 81, and Figure 6 is a side view showing the restriction mechanism 81 attached to the side plate 3a. Figure 5 shows the restriction mechanism 81 attached to the left side plate 3a.

[0033] As shown in FIG. 5 , the restriction mechanism 81 includes a pressing lever 83, an opening / closing lever 85, a compression coil spring 87 as an elastic member, and a support plate 89 that supports these components. Upper and lower pivot shafts 89a and 89b are provided on the bottom plate of the support plate 89. Furthermore, an upper restricting piece 89c that protrudes inward is provided on the rear plate of the support plate 89 between the pivot shafts 89a and 89b. Furthermore, a lower restricting piece 89d that protrudes upward is provided on the lower plate of the support plate 89. Furthermore, a plurality of positioning pins 89e and hooks 89f are provided on the support plate 89. Meanwhile, positioning holes and engagement pieces (not shown) corresponding to the positioning pins 89e and hooks 89f are provided on the outer surfaces of the left and right side plates 3a. The support plate 89 is attached to the left and right side plates 3a in a predetermined position by aligning the positioning pins 89e of the support plate 89 with the positioning holes of the left and right side plates 3a and engaging the hooks 89f with the engagement pieces.

[0034] The pressure lever 83 is a generally L-shaped member when viewed from the left-right direction, and includes a pressure arm 91 and a restriction arm 93 that intersect at approximately 90 degrees, and a bearing hole 95 between the arms 91 and 93. A triangular protrusion 97 is formed on the inner surface (the surface facing the restriction arm 93) of the tip of the pressure arm 91 when viewed from the left-right direction. A spring support surface 93a that faces diagonally downward is formed on the tip of the restriction arm 93. The pressure lever 83 is rotatably supported on a rotation shaft 89a on the upper side of the support plate 89, with the pressure arm 91 facing forward and the restriction arm 93 facing backward. The restriction arm 93 abuts against an upper restriction piece 89c of the support plate 89 from below, restricting upward rotation. As a result, the pressure arm 91 is maintained in an orientation in which the protrusion 97 faces directly downward, restricting downward rotation while allowing upward rotation.

[0035] The opening / closing lever 85 is a zigzag-shaped member as viewed from the left and right in FIG. 5 . The opening / closing lever 85 includes a restricting portion 101 that is substantially Z-shaped as viewed from the left and right in FIG. 5 , and a contact portion 103 that is substantially L-shaped as viewed from the left and right and connected to the tip of the restricting portion 101. A bearing hole 105 is formed at the base end of the restricting portion 101, and a spring support surface 101a that faces diagonally upward is formed at the tip. The contact portion 103 is bent at an obtuse angle as viewed from the left and right. The opening / closing lever 85 is rotatably supported on a pivot shaft 89b on the lower side of the support plate 89 with the contact portion 103 facing forward. The restricting portion 101 contacts a lower restricting piece 89d of the support plate 89 from above, restricting downward rotation. This maintains the opening / closing lever 85 in a position where the contact portion 103 protrudes forward from the support plate 89.

[0036] The compression coil spring 87 is a so-called compression spring, with one end fitted to a protrusion on the spring support surface 93a of the regulating arm 93 of the pressing lever 83 and the other end fitted to a protrusion on the spring support surface 101a of the regulating portion 101 of the opening / closing lever 85. As described above, the upward rotation of the regulating arm 93 of the pressing lever 83 is restricted, and the downward rotation of the regulating portion 101 of the opening / closing lever 85 is restricted, so the positions of both spring support surfaces 93a, 101a are fixed. The compression coil spring 87 is slightly compressed between the spring support surfaces 93a, 101a. As a result, an elastic return force generated by the compression of the compression coil spring 87 is applied to the regulating arm 93 of the pressing lever 83, pressing the regulating arm 93 against the upper regulating piece 89c. In other words, an upward load is applied to the regulating arm 93, and a downward load is applied to the pressing arm 91. The load applied to the pressing arm 91 is referred to as a first load.

[0037] As shown in Figure 6, when the support plate 89 is attached to a predetermined position on the outer surface of the left and right side plates 3a, the protrusion 97 of the pressing arm 91 of the pressing lever 83 protrudes upward into the cutout hole 15 in the left and right side plates 3a. Also, the abutment portion 103 of the opening / closing lever 85 protrudes forward from the opening 5. This position of the pressing lever 83 and the opening / closing lever 85 is defined as the initial position of the pressing lever 83 and the opening / closing lever 85. A first load is applied to the pressing arm 91, restricting upward rotation, i.e., rotation in the direction away from the cutout hole 15. In this way, the first load is applied to the pressing arm 91 in the direction opposite to the direction away from the cutout hole 15 (downward).

[0038] The operation of the regulating mechanism 81 in the image forming apparatus 1 having the above configuration will be described with reference to Figure 6 and Figures 7 to 10. Figures 7 to 10 are side views showing the regulating mechanism 81.

[0039] First, we will describe the state in which the imaging unit 43 is pulled out from the housing 3. When the imaging unit 43 is pulled out from the housing 3, the front cover 7 is open, and the pressing lever 83 and the opening / closing lever 85 of the regulating mechanism 81 are maintained in their initial positions, as shown in Figures 6 and 7. That is, the regulating arm 93 abuts against the upper regulating piece 89c, and the regulating portion 101 abuts against the lower regulating piece 89d, the protruding portion 97 of the pressing arm 91 of the pressing lever 83 protrudes from above into the notched hole 15, and the abutting portion 103 of the opening / closing lever 85 protrudes forward from the opening 5.

[0040] When the imaging unit 43 is attached to the housing 3 through the opening 5, as described above, the pins 17 on the left and right side plates 3a enter the cutout holes 61 in the left and right unit frames 53 of the imaging unit 43, and the pins 59 of the imaging unit 43 enter the cutout holes 15 in the left and right side plates 3a. At this time, the rear surfaces of the pins 59 that protrude outward from the side plates 3a through the cutout holes 15 come into contact with the protrusions 97 of the pressing arms 91. As described above, a first load is applied to the pressing arms 91 downward (in the direction opposite to the direction away from the cutout holes 15). When the pins 59 pass through the cutout holes 15, the pressing arms 91 are pushed up by the pins 59 (see the chain line in FIG. 6 ) against the first load and rotate upward (see the two-dot chain line in FIG. 6 ). 6, and the restricting arm 93 moves downward away from the upper restricting piece 89c. When the pin 59 hits the rear end (deep end) of the cutout hole 15, the pin 59 passes the tip of the protrusion 97, and the pressing arm 91 rotates downward due to the first load. In other words, the pressing lever 83 rotates clockwise in FIG. 6, and the protrusion 97 abuts against the front surface of the pin 59.

[0041] When the pressing lever 83 returns to its initial position, the rear inclined surface of the protrusion 97 abuts against the front surface of the pin 59, pressing the pin 59 against the rear end (rear end) of the notched hole 15 and restricting movement of the pin 59. A first load is applied to the pressing arm 91 downward (in the direction opposite to the direction away from the notched hole 15), restricting upward rotation.

[0042] After the imaging unit 43 is attached to the housing 3, the front cover 7 is rotated upward to close the opening 5. When the front cover 7 is rotated upward, the abutment portion 103 of the opening / closing lever 85 abuts the protruding piece 13 of the stopper 11 of the front cover 7 from below, as shown in FIG. 8 . Specifically, the tip surface 13b of the protruding piece 13 abuts the underside of the abutment portion 103. When the front cover 7 is further rotated upward, the opening / closing lever 85 is pushed up by the protruding piece 13, and begins to rotate upward, leaving the lower restricting piece 89d, as shown in FIG. 9 . Specifically, the underside of the abutment portion 103 contacts the tip surface 13b, the inclined surface 13c, and the upper surface 13a of the protruding piece 13 in that order. As shown in FIG. 10 , when the opening 5 is completely closed by the front cover 7, the abutment portion 103 rides up onto the protruding piece 13.

[0043] When the opening / closing lever 85 rotates upward in this manner, the compression coil spring 87 begins to be compressed between the two spring support surfaces 93a, 101a. This increases the elastic restoring force generated by the compression of the compression coil spring 87, and the load applied to the pressing arm 91 increases. This load is referred to as the second load. The second load is greater than the first load by the amount of the elastic restoring force generated by the elastic deformation of the compression coil spring 87 due to the rotation of the opening / closing lever 85. This more strongly restricts the upward rotation of the pressing arm 91. Once the front cover 7 has rotated until the opening 5 is closed, it is locked by a locking mechanism (not shown).

[0044] When the imaging unit 43 is to be pulled out from the housing 3, the front cover 7 is rotated downward to open the opening 5, and then the imaging unit 43 is pulled out forward. When the pin 59 abuts against the protrusion 97 of the pressing arm 91, the pressing arm 91 is pushed by the pin 59 against the first load and rotates upward, and then the pin 59 separates from the protrusion 97, and the pressing arm 91 rotates downward.

[0045] That is, in the first embodiment, the compression coil spring 87 is supported by the opening / closing lever 85 and applies a pressing force to the pressing lever 83. The opening / closing lever 85 is provided inside the housing 3 with a contact portion 103, which is a part of the opening / closing lever 85, protruding outward from the housing 3. The front cover 7 is provided with a protruding piece 13 protruding from the surface of the front cover 7 facing the housing 3. The protruding piece 13 is provided at a position where it will come into contact with the contact portion 103 of the opening / closing lever 85 while the front cover 7 moves from the open position to the closed position with the protruding piece 13 abutting against the contact portion 103. When the front cover 7 moves to the closed position with the protruding piece 13 abutting against the contact portion 103, the opening / closing lever 85 rotates due to the pressure of the protruding piece 13 on the contact portion 103, further elastically deforming the compression coil spring 87, and the elastic return force of the compression coil spring 87 applies the second load to the pressing lever 83.

[0046] As described above, according to the present invention, an appropriate load is applied to the pressing lever 83 when the front cover 7 is closed or open. Therefore, even if an external force such as vibration or impact is applied to the housing 3, the rotation of the pressing lever 83 is restricted, preventing inadvertent movement of the pin 59 of the imaging unit 43. Specifically, when the front cover 7 is open, applying a load that does not prevent the pin 59 from passing through the notched hole 15 allows the imaging unit 43 to be smoothly pulled out or installed. However, even slight movement of the pin 59 does not have any particular impact. Furthermore, because a large load is applied to the pressing lever 83 when the front cover 7 is closed, misalignment of the imaging unit 43 and poor image quality can be prevented even if an external force is applied due to vibration of the housing 3 during image formation.

[0047] Next, a modified embodiment of the first embodiment will be further described. FIG. 11 is a side view showing an opening / closing lever 85 according to a modified embodiment of the first embodiment. The opening / closing lever 85 according to the modified embodiment differs from the opening / closing lever 85 according to the first embodiment in that a protrusion 1031 is further provided. That is, the opening / closing lever 85 according to the modified embodiment has the same configuration as the opening / closing lever 85 according to the first embodiment, except for the additional protrusion 1031. The protrusion 1031 is provided at the contact portion 103 of the opening / closing lever 85, protruding from the portion that contacts the protruding piece 13 of the front cover 7. The protrusion 1031 is provided so as to extend across the entire width of the contact portion 103 of the opening / closing lever 85 in the width direction (the depth direction in FIG. 11 ) of the contact portion 103.

[0048] 12 is a partially enlarged side view of the stopper 11 of the front cover 7. The protruding piece 13 of the front cover 7 is provided with a locking portion 13d that protrudes toward the abutment portion 103 at a portion that is on the abutment portion 103 side of the opening / closing lever 85 when the front cover 7 is in a closed position relative to the housing 3. In the modified embodiment, the stopper 11 and protruding piece 13 of the front cover 7 are similar to those in the first embodiment described above, but in the modified embodiment, the protruding portion of the protruding piece 13 that is formed between the inclined surface 13c and the upper surface 13a functions as the locking portion 13d.

[0049] When the front cover 7 is rotated upward and moves from the open position to the closed position relative to the housing 3, the abutment portion 103 of the opening / closing lever 85 abuts from below against the protruding piece 13 of the stopper 11 of the front cover 7, as shown in Fig. 8 above. As the front cover 7 continues to rotate, the opening / closing lever 85 is pushed up by the protruding piece 13, and begins to rotate upward, leaving the lower restricting piece 89d, as shown in Fig. 9 above. The lower surface of the abutment portion 103 then comes into contact with the tip surface 13b, inclined surface 13c, and upper surface 13a of the protruding piece 13 in that order.

[0050] When the upper surface 13a of the protruding piece 13 contacts the lower surface of the abutment portion 103 in this manner, the locking portion 13d contacts the protrusion portion 1031 from the outward direction of the housing 3 (Fr (front) direction in Figure 9), and in this state the locking portion 13d and the protrusion portion 1031 are temporarily locked together.

[0051] After the locking, if the rotation continues further toward the closed position, as shown in Fig. 13, as the front cover 7 moves toward the closed position, the locking portion 13d passes over the protrusion 1031 and moves toward the Rr side (rear side) in Fig. 13, and the locking portion 13d enters further into the housing 3 than the protrusion 1031. Then, when the opening 5 is completely closed by the front cover 7 and the front cover 7 is in the closed position, the locking portion 13d is locked with the protrusion 1031 from the inside of the housing 3, and the abutment portion 103 rides up onto the protruding piece 13. At this time, the opening / closing lever 85 is pressed downward in Fig. 13 by the compression coil spring 87, so the opening / closing lever 85 is maintained in the position shown in Fig. 13.

[0052] In this modified embodiment, when the front cover 7 is in the closed position, the load applied to the pressing lever 83 increases, suppressing movement of the pin 59 and preventing misalignment of the imaging unit 43. Furthermore, the locking portion 13d is locked with the protrusion 1031 from the inside of the housing 3, suppressing rotation of the front cover 7 in the direction in which the front cover 7 is in the open position. This maintains the closed position of the front cover 7 more stably than in the first embodiment. Furthermore, since the restricting mechanisms 81 are provided facing the stoppers 11 at the respective positions where the stoppers 11 are provided, the locking portions 13d and the protrusions 1031 lock with each other near both ends of the housing 3 when the front cover 7 is in the closed position. Therefore, the front cover 7 is fixed (locked) at these both ends when closed to the housing 3. This prevents the front cover 7 from closing on only one of the both ends of the housing 3. Furthermore, the opening / closing lever 85 in the modified embodiment can be constructed by providing a protrusion 1031 on the opening / closing lever 85 in the first embodiment, thereby achieving stable locking of the front cover 7 to the housing 3 without further increasing the number of parts.

[0053] On the other hand, when the front cover 7 is rotated from the closed position to the open position, the front cover moves in a direction away from the housing 3 (toward the outside of the housing 3) due to the rotation. At this time, the locking portion 13d, which is engaged with the protrusion 1031 from the inside of the housing 3, moves past the protrusion 1031 and toward the Fr side (front side) in FIG. 13 as the front cover 7 moves. The locking portion 13d then moves toward the outside of the housing 3 beyond the protrusion 1031. At this time, the opening / closing lever 85 rotates upward in FIG. 13 against the pressure of the compression coil spring 87 due to the pressing force exerted by the locking portion 13d on the protrusion 1031 as it tries to move past the protrusion 1031. Therefore, the opening / closing lever 85 can move toward the outside of the housing 3 beyond the protrusion 1031 of the locking portion 13d. Thereafter, the front cover 7 rotates to the open position in the same manner as in the first embodiment.

[0054] Next, the restriction mechanism 81 in the image forming apparatus 1 according to the second embodiment will be described with reference to Figures 14 to 17. Figure 14 is a perspective view showing the restriction mechanism 81, and Figures 15 to 17 are side views showing the restriction mechanism 81.

[0055] As shown in Figure 14, the restriction mechanism 81 includes a pressing lever 113, an opening / closing lever 115, a tension coil spring 117 as an elastic member, and a support plate 119 that supports these. In other words, in the second embodiment, the tension coil spring 117 is used instead of the compression coil spring 87 in the first embodiment. Below, differences from the first embodiment will be mainly described.

[0056] The pressing lever 113 is a linear member, and has a protrusion 121 formed at its tip that is triangular when viewed from the left and right. Furthermore, a spring support pin 123 is formed at the tip. A bearing hole 125 is formed at the base end of the pressing lever 113. The pressing lever 113 is rotatably supported on a rotation shaft 119a on the upper side of the support plate 119, with its tip facing forward and its protrusion 121 facing downward. The pressing lever 113 abuts against an upper restricting piece 119c of the support plate 119 from above, restricting downward rotation, while allowing upward rotation.

[0057] The opening / closing lever 115 is a generally T-shaped member when viewed from the left and right, and includes a support arm 131, a contact arm 133, and a restriction arm 135 extending in opposite directions from the tip of the support arm 131. A bearing hole 137 is formed in the base end of the support arm 131. A spring support pin 139 is formed in the tip of the restriction arm 135. The opening / closing lever 115 is rotatably supported on a rotation shaft 119b on the lower side of the support plate 119, with the contact arm 133 facing forward. The restriction arm 135 abuts against a lower restriction piece (not shown) of the support plate 119 from above, restricting downward rotation. This maintains the opening / closing lever 115 in a position where the contact arm 133 protrudes forward from the support plate 119.

[0058] One end of the tension coil spring 117 is fixed to the spring support pin 123 of the pressing lever 113, and the other end is fixed to the spring support pin 139 of the opening / closing lever 115. As described above, the pressing lever 113 is restricted from rotating downward, and the restricting arm 135 of the opening / closing lever 115 is restricted from rotating upward, so the positions of both spring support pins 123, 139 are fixed. The tension coil spring 117 is slightly pulled between both spring support pins 123, 139. As a result, an elastic return force generated by the pulling of the tension coil spring 117 is applied to the pressing lever 113, pressing the pressing lever 113 against the upper restricting piece 119c. In other words, a downward load (first load) is applied to the pressing lever 113.

[0059] When the imaging unit 43 is pulled out from the housing 3, the front cover 7 is open, the protrusion 121 of the pressing lever 113 protrudes from above into the cutout holes 15 in the left and right side plates 3a, and the abutment arm 133 of the opening / closing lever 115 protrudes forward from the opening 5. When the pin 59 of the imaging unit 43 enters the cutout holes 15 in the left and right side plates 3a during installation, the rear surface of the pin 59 abuts against the protrusion 121 of the pressing lever 113 protruding into the cutout hole 15, and the pressing lever 113 is pushed by the pin 59 against the first load and rotates upward. When the pin 59 hits the rear end (rear end) of the cutout hole 15, the pin 59 passes the tip of the protrusion 121, and the pressing lever 113 rotates downward. As a result, the rear inclined surface of the protrusion 121 abuts against the front surface of the pin 59 from above, pressing the pin 59 against the rear end of the notched hole 15 and restricting the movement of the pin 59. A first load is applied to the pressing lever 113 in the direction opposite to the direction away from the notched hole 15.

[0060] After the imaging unit 43 is attached to the housing 3, the front cover 7 is rotated upward to close the opening 5. When the front cover 7 is rotated upward, the abutment arm 133 of the opening / closing lever 115 abuts from below against the protruding piece 13 of the stopper 11 of the front cover 7, as shown in FIG. 16 . More specifically, the tip surface 13b ( FIG. 6 ) of the protruding piece 13 abuts against the underside of the abutment arm 133. When the front cover 7 is further rotated upward, the opening / closing lever 115 is pushed upward by the protruding piece 13 and begins to rotate upward, releasing the lower restricting piece. As shown in FIG. 17 , when the opening 5 is completely closed by the front cover 7, the abutment arm 133 rides up onto the protruding piece 13.

[0061] That is, the tension coil spring 117 is supported by the opening / closing lever 85 and applies a force to the pressing lever 83 to pull the pressing lever 83 in. The opening / closing lever 85 is provided within the housing 3 with a contact portion 103, which is a part of the opening / closing lever 85, protruding outward from the housing 3. The front cover 7 is provided with a protruding piece 13 protruding from the surface of the front cover 7 facing the housing 3. The protruding piece 13 is provided at a position where it will abut against the abutment portion 103 of the opening / closing lever 85 while the front cover 7 moves from the open position to the closed position with the protruding piece 13 abutting against the abutment portion 103, causing the opening / closing lever 85 to rotate and elastically deform the tension coil spring 117 in a direction that stretches it, and the elastic return force of the tension coil spring 117 applies the second load to the pressing lever 83.

[0062] When the opening / closing lever 115 rotates upward in this manner, the tension coil spring 117 begins to be pulled between the two spring support pins 123 and 139. This increases the elastic restoring force (load) generated by the tension of the tension coil spring 117, and the load applied to the pressing lever 113 increases. This load is referred to as the second load. The second load is greater than the first load. This more strongly restricts the upward rotation of the pressing lever 113.

[0063] As explained above, in the regulating mechanism 81 of the second embodiment, an appropriate load is applied to the pressing lever 83 when the front cover 7 is in the closed and open states, so that even if an external force such as vibration or impact is applied to the housing 3, the rotation of the pressing lever 83 is regulated, and inadvertent movement of the pin 59 of the imaging unit 43 can be prevented.

[0064] Although the present invention has been described with reference to specific embodiments, the present invention is not limited to the above embodiments, and those skilled in the art may modify the above embodiments without departing from the scope and spirit of the present invention.

Claims

1. A housing having an opening on a side surface, a cover capable of opening and closing the opening, an imaging unit arranged in the housing and capable of being pulled out through the opening in a predetermined pulling direction, a notched hole formed in a side edge of the opening along the pulling direction, a pin arranged in the imaging unit and abutting against the inner end of the notched hole to position the imaging unit in the housing, and a restriction mechanism for restricting movement of the pin within the notched hole, wherein the restriction mechanism comprises: a pressing lever that is rotatable in a separating direction away from the notched hole from a state in which it abuts against the pin within the notched hole, an opening / closing lever that rotates in conjunction with the closing operation of the cover, and an elastic member that is arranged between the pressing lever and the opening / closing lever in an elastically deformed state and applies a load to the pressing lever in a direction opposite to the separating direction, wherein when the cover is open, the elastic restoring force of the elastic member applies a first load to the pressing lever, When the cover is closed, the opening / closing lever rotates to further elastically deform the elastic member, and the elastic restoring force of the elastic member applies a second load greater than the first load to the pressing lever.

2. The image forming apparatus according to claim 1, wherein the elastic member is a compression coil spring that is supported by the opening / closing lever and applies a pressing force to the pressure lever, the opening / closing lever is provided within the housing with a contact portion that is a part of the opening / closing lever protruding outward from the housing, the cover is provided with a protruding piece that protrudes from the surface facing the housing, the protruding piece is positioned so as to contact the contact portion of the opening / closing lever while the cover moves from an open position relative to the housing to a closed position, and when the cover moves to the closed position with the protruding piece abutting the contact portion, the opening / closing lever rotates due to the pressure of the protruding piece on the contact portion, further elastically deforming the elastic member, and the elastic return force of the elastic member applies the second load to the pressure lever.

3. The image forming apparatus of claim 2, wherein the abutment portion of the opening / closing lever is provided with a protrusion protruding from a portion that abuts against the protruding piece of the cover, and the protruding piece of the cover is provided with a locking portion that protrudes toward the abutment portion at a portion that becomes the abutment portion side when the cover is in the closed position, and when the protrusion abuts against the abutment portion and the opening / closing lever rotates while the cover moves from the open position to the closed position relative to the housing, the locking portion comes into contact with the protrusion from the outside of the housing and the locking portion and the protrusion are once locked, and then as the cover moves to the closed position, the locking portion goes beyond the protrusion and enters toward the interior of the housing, and when the cover is in the closed position, the locking portion is locked to the protrusion from the inside of the housing.

4. The image forming apparatus according to claim 1, wherein the elastic member is a tension coil spring that is supported by the opening / closing lever and applies a force to the pressing lever to pull the pressing lever in, the opening / closing lever is provided within the housing with a contact portion that is a part of the opening / closing lever protruding outward from the housing, the cover is provided with a protruding piece that protrudes from the surface facing the housing, the protruding piece is positioned so as to contact the contact portion of the opening / closing lever while the cover moves from an open position relative to the housing to a closed position, and when the cover moves to the closed position with the protruding piece abutting the contact portion, the opening / closing lever rotates due to the pressure of the protruding piece on the contact portion, elastically deforming the elastic member in a direction that stretches it, and the elastic return force of the elastic member applies the second load to the pressing lever.