JP2010266620A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that accurately positions a movable cover with respect to a fixed cover. <P>SOLUTION: In the image forming apparatus 100, a body case 40 has the fixed cover 41, the movable cover 400 opened and closed to the fixed cover 41 by rocking around a shaft center of a rocking shaft 411, and engaging mechanisms 50 and 420 fixing the movable cover 400 in a closed state. The engaging mechanisms 50 and 420 have a pressing part 50, provided in a frame 200 and capable of applying pressing force F0 when the movable cover 400 is closed, and a part to be pressed 420, provided in the movable cover 400 and pressed by the pressing part 50 when the movable cover 400 is closed. The pressing part 50 applies component force F1 of the pressing force F0 in a first direction (from bottom to top) from the shaft center side, so that the part to be pressed 420 is displaced in the first direction. A first abutment surface 41G, positioning the movable cover 400 in the first direction by abutting on the part to be pressed 420 when the movable cover 400 is closed, is formed in the fixed cover 41. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus.

  Patent Document 1 discloses an example of a conventional image forming apparatus. The image forming apparatus includes an image forming unit that forms an image on a recording medium, a frame that supports the image forming unit, and a main body case that houses the image forming unit and the frame.

  The main body case includes a fixed cover that covers the upper surface of the image forming apparatus and a movable cover that covers the front surface of the image forming apparatus. The fixed cover is fixed above the frame. The movable cover is pivotally supported so as to be swingable around a lower axis with respect to the frame, and can be opened or closed with respect to the fixed cover.

  The movable cover is provided with a pressing portion capable of applying a pressing force when the movable cover is closed. On the other hand, the frame is provided with a pressed portion that is pressed by the pressing portion when the movable cover is closed. When the pressing portion presses the pressed portion, the pressing force imparts a component force of the pressing force in a direction from the lower shaft core side to the upper side.

  In this image forming apparatus, when the movable cover is closed, the pressed portion is pressed by the pressing portion, so that the movable cover is fixed in a closed state with respect to the frame.

JP 2008-32836 A

  By the way, in the conventional image forming apparatus, in order to realize a smooth opening / closing operation of the movable cover, the movable cover has an appropriate backlash and is pivotally supported so as to be swingable around the axis. For this reason, when the pressed portion is pressed upward from the lower shaft core side by the pressing portion, the pressing portion easily shifts downward due to the reaction force acting on the pressing portion and the play, and accordingly, the movable portion is movable. The cover is also easily displaced downward with respect to the frame and the fixed cover. For this reason, in the conventional image forming apparatus, it is difficult to accurately position the movable cover with respect to the fixed cover. As a result, a vertical gap between the fixed cover and the movable cover or a vertical step between the outer surface of the fixed cover and the outer surface of the movable cover is likely to occur, and a problem that the appearance of the main body case deteriorates may occur.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of accurately positioning a movable cover with respect to a fixed cover.

An image forming apparatus of the present invention includes an image forming unit that forms an image on a recording medium;
A frame that supports the image forming means;
A main body case for storing the image forming means and the frame;
The main body case includes a fixed cover fixed to the frame, a movable cover that is pivotally supported about an axis around the frame or the fixed cover, and is opened or closed with respect to the fixed cover. An image forming apparatus having an engagement mechanism for fixing the movable cover in a closed state with respect to the frame or the fixed cover,
The engagement mechanism is provided on the frame or the fixed cover and can be applied with a pressing force when the movable cover is closed, and is provided on the movable cover and is pressed against the pressing portion when the movable cover is closed. A pressed portion to be
The pressing portion applies the pressing force or a component force of the pressing force in the first direction from the shaft core side, and displaces the pressed portion in the first direction.
The fixed cover is formed with a first contact surface that contacts the pressed portion when the movable cover is closed and positions the movable cover in the first direction. ).

  According to the image forming apparatus of the present invention, when the movable cover is closed, the pressing portion applies a pressing force or a component force of the pressing force in the first direction from the axial center side, and the pressed portion provided on the movable cover. Is displaced in the first direction. Then, when the first contact surface of the fixed cover comes into contact with the pressed portion of the movable cover, the pressed portion is positioned in the first direction, thereby positioning the movable cover in the first direction. For this reason, even if the movable cover is pivotally supported with respect to the shaft core, the gap in the first direction between the fixed cover and the movable cover, or the first surface between the outer surface of the fixed cover and the outer surface of the movable cover. It is easy to maintain in a state where the step in one direction is reduced.

  Therefore, according to the image forming apparatus of the present invention, the movable cover can be accurately positioned with respect to the fixed cover, and as a result, the appearance of the main body case can be prevented from being deteriorated.

  In the image forming apparatus of the present invention, the fixed cover is formed with a fixed edge that faces the movable cover in the second direction that intersects the first direction and is orthogonal to the axis when the movable cover is closed. The pressing portion and the pressed portion are formed with a pressing surface that abuts on each other to apply a component force of the pressing force in the second direction and to bring the movable cover closer to the fixed edge in the second direction. It is desirable (Claim 2).

  According to this configuration, the component force of the pressing force that the pressing portion applies to the pressed portion when the movable cover is closed is applied in the first direction and is also applied in the second direction. Then, the movable cover is moved closer to the fixed edge of the fixed cover in the second direction by the component force of the pressing force in the second direction. For this reason, the clearance in the second direction between the fixed edge of the fixed cover and the movable cover can be further reduced.

  In the image forming apparatus of the present invention, the pressing portion is positioned on the distal end side in the first direction with respect to the elastic portion that generates the pressing force, and can be displaced in the first direction by being pressed by the elastic portion. The pressing surface is formed on the link portion, the guide surface formed by inclining a plane orthogonal to the first direction toward the second direction, and the pressed portion, and closing the movable cover It is sometimes desirable to comprise a guided surface that abuts the guiding surface.

  According to this configuration, the component force of the pressing force applied by the pressing portion can be applied in the first direction and the second direction without increasing the number of parts.

  In the image forming apparatus of the present invention, the movable cover is formed with a movable edge farthest from the axis, and the pressing portion is disposed so as to be in a positional relationship close to the movable edge when the movable cover is closed. (Claim 4).

  According to this configuration, the position where the pressed portion receives the pressing force of the pressing portion can be brought close to the movable edge of the movable cover, so that deformation of the movable cover due to the pressing force of the pressing portion is suppressed, The displacement of the movable edge due to the deformation can be suppressed.

  In the image forming apparatus of the present invention, the fixed cover has a second contact surface that contacts the surface facing the second direction of the movable cover or the pressed portion when the movable cover is closed, and positions the movable cover in the second direction. It is desirable to form (claim 5).

  According to this configuration, it is easy to maintain a state in which the gap in the second direction between the fixed edge of the fixed cover and the movable cover is reduced. For this reason, the movable cover can be positioned more accurately with respect to the fixed cover, and as a result, the appearance of the main body case can be reliably prevented from being deteriorated.

  In the image forming apparatus of the present invention, the fixed cover is an upper surface cover that covers the upper surface of the main body case, the movable cover is a front surface cover that covers the front surface of the main body case, and the first contact surface is on the upper edge of the movable cover. It is desirable to be provided in an extending portion that extends downward from the front edge portion of the adjacent upper surface cover.

  According to the specific configuration, the front cover that can be opened and closed can be accurately positioned with respect to the top cover.

  In the image forming apparatus of the present invention, the fixed cover is a side cover that covers the side surface of the main body case, the movable cover is a front cover that covers the front surface of the main body case, and the first contact surface is located on the outer side in the width direction of the movable cover. It is desirable to be provided in the extending part extended toward the inner side in the width direction from the front edge part of the side cover adjacent to the side edge part (Claim 7).

  According to the specific configuration, the front cover that can be opened and closed can be accurately positioned with respect to the side cover.

1 is a perspective view illustrating an image forming apparatus according to a first exemplary embodiment. 1 is a perspective view illustrating a configuration when a movable cover is closed, according to an image forming apparatus of Embodiment 1. FIG. 1 is a perspective view illustrating a configuration when a movable cover is closed, according to an image forming apparatus of Embodiment 1. FIG. FIG. 3 is a perspective view illustrating the configuration of the image forming apparatus according to the first embodiment when the movable cover is opened. FIG. 3 is a perspective view illustrating the configuration of the image forming apparatus according to the first embodiment when the movable cover is opened. 1 is a schematic diagram schematically illustrating a configuration of an image forming unit according to an image forming apparatus of Example 1. FIG. FIG. 3 is a perspective view illustrating the configuration when the movable cover is closed, with a part of the movable cover being omitted, according to the image forming apparatus of Example 1. FIG. 8 is an enlarged perspective view of a portion A shown in FIG. 7 according to the image forming apparatus of Embodiment 1. FIG. 3 is a left side view illustrating the configuration of the image forming apparatus according to the first embodiment when the movable cover is closed. FIG. 10 is an enlarged left side view of a portion B shown in FIG. 9 according to the image forming apparatus of Embodiment 1. FIG. 3 is a perspective view illustrating the configuration of the image forming apparatus according to the first embodiment when the movable cover is opened. FIG. 12 is an enlarged perspective view of a C portion illustrated in FIG. 11 according to the image forming apparatus of Embodiment 1. FIG. 4 is a left side view illustrating the configuration of the image forming apparatus according to the first embodiment when the movable cover is opened. FIG. 14 is an enlarged left side view of a portion D illustrated in FIG. 13 according to the image forming apparatus of Embodiment 1. FIG. 3 is an enlarged left side view illustrating a fixed cover, a movable cover, and an engagement mechanism in the image forming apparatus according to the first exemplary embodiment. FIG. 16 is an essential part enlarged cross-sectional view showing a modification of the second contact surface according to the image forming apparatus of Example 1 (showing a ZZ cross-section in FIG. 15). FIG. 6 is an enlarged perspective view of a main part showing a side cover and a pressed part in the image forming apparatus of Example 2. FIG. 10 is an enlarged left side view illustrating a fixed cover, a movable cover, and an engagement mechanism in the image forming apparatus according to the second exemplary embodiment.

  Embodiments 1 and 2, which are examples of specific embodiments of the present invention, will be described below with reference to the drawings.

Example 1
As shown in FIG. 1, a printer 100 as an image forming apparatus of Example 1 is a color laser printer that forms an image having a plurality of colors on a sheet (including an OHP sheet) as a recording medium by an electrophotographic method. It is.

<Overall configuration of printer>
As shown in FIGS. 2 to 5, the printer 100 includes an image forming unit 300 that forms an image on a sheet, and a substantially box-shaped frame 200 that detachably supports the image forming unit 300. As shown in FIG. 1, the printer 100 includes an image forming unit 300 and a resin main body case 40 that houses the frame 200. In the following description, the side of the printer 100 where the below-described front cover 400 is provided (that is, the front side of the printer 100) is the front. 2 is a perspective view of the printer 100 with the front cover 400 closed as viewed from the upper right front, and FIG. 3 is a perspective view of the printer 100 as viewed from the lower left rear. 4 is a perspective view of the printer 100 with the front cover 400 opened, as viewed from the upper right front, and FIG. 5 is a perspective view of the printer 100 as viewed from the lower left rear. Further, FIGS. 2 to 5 are drawn by omitting a part of the configuration of a belt unit 310 (see FIG. 6) described later and details of a lock member 500 described later.

<Configuration of Image Forming Unit>
FIG. 6 is a schematic diagram schematically illustrating the configuration of the image forming unit 300. As shown in FIG. 6, the image forming unit 300 includes four process units 320 corresponding to each color of black (K), yellow (Y), magenta (M), and cyan (C), a driving roller 311 and a driven roller. 3, and a belt unit 310 in which a conveyor belt 313 is installed between the belt unit 312 and the belt unit 312. The process unit 320 is located above the belt unit 310. The four process units 320 are arranged in the front-rear direction in the order of black, yellow, magenta, and cyan from the front side of the printer 100 (the above configuration is referred to as “direct tandem method”). The four process units 320 are individually provided in four storage units (not shown) provided in the drum subunit 351 (see FIGS. 4 and 5) constituting the frame of the image forming unit 350 described above. Removably held.

  Each process unit 320 includes a photosensitive drum 321, a scorotron charger 322, and a developing cartridge 324. The photosensitive drum 321 includes a grounded metal drum main body, and the surface layer is covered with a positively chargeable photosensitive layer made of polycarbonate or the like.

  The scorotron charger 322 is disposed opposite to the photosensitive drum 321 at a predetermined interval so as not to come into contact with the photosensitive drum 321 at an obliquely upper rear side of the photosensitive drum 321. The scorotron charger 322 uniformly charges the surface of the photosensitive drum 321 to positive polarity by generating corona discharge from a charging wire such as tungsten. The developing cartridge 324 has a toner storage chamber 325 therein, and positively triboelectrically charges black, cyan, magenta, or yellow positively charged non-magnetic one-component toner (an example of a developer) stored therein. In addition, the toner is supplied to the photosensitive drum 321 via the developing roller 326.

  The belt unit 310 includes four transfer rollers 314 provided at positions facing the respective photosensitive drums 321 with the conveyance belt 313 interposed therebetween. When the driving roller 311 rotates in the clockwise direction in FIG. 6, the conveying belt 313 is also rotated in the same direction. The sheet P is supplied to the surface of the conveyor belt 313 from various feed rollers (not shown) such as a feed roller from a feed tray (not shown) inserted in the lower part of the frame 200. Then, the sheet P is conveyed to the rear of the printer 100 through the facing portion between each photosensitive drum 321 and each transfer roller 314.

  A scanner unit 330 is provided above each process unit 320. The scanner unit 330 includes a semiconductor laser that generates laser beams Lk, Ly, Lm, and Lc corresponding to image data of each color and a polygon mirror that deflects the laser beam L (all not shown), and each photosensitive drum 321. Are well known for scanning exposure. For this reason, the surface of each photosensitive drum 321 is uniformly positively charged by the scorotron charger 322 when rotating. Thereafter, exposure is performed by high-speed scanning of the laser beams Lk, Ly, Lm, and Lc from the scanner unit 330, and an electrostatic latent image corresponding to an image to be formed on the paper P is formed. Next, when the developing roller 326 is rotated and the positively charged toner carried on the developing roller 326 comes into contact with the photosensitive drum 321 so as to face the surface, the static image formed on the surface of the photosensitive drum 321. The electric latent image is supplied. As a result, the electrostatic latent image on the photosensitive drum 321 is visualized, and a toner image with toner attached only to the exposed portion is carried on the surface of the photosensitive drum 321.

  Thereafter, the toner image carried on the surface of each photoconductive drum 321 has a constant current applied to the transfer roller 314 when the paper P conveyed by the conveyance belt 313 passes between the photoconductive drum 321 and the transfer roller 314. The images are sequentially transferred onto the paper P by the negative transfer bias applied by the control. The sheet P having the toner image transferred thereon is then conveyed to a fixing device 340 disposed behind the belt unit 310.

  The fixing device 340 includes a heating roller 341 that is rotationally driven with a heat source such as a halogen lamp, and a pressure roller 342 that is disposed below the heating roller 341 so as to face the heating roller 341 and is driven to rotate. I have. The fixing device 340 heats and fixes the toner image onto the paper P by heating the paper P carrying the four-color toner images while being nipped and conveyed by the heating roller 341 and the pressure roller 342. Then, the paper P on which the toner image is thermally fixed is discharged to a paper discharge tray 41T (see FIG. 1) provided on the upper surface of the printer 100 by various rollers (not shown).

<Frame structure>
As shown in FIGS. 2 to 5, the frame 200 includes a pair of sheet metal frames 210 that support the image forming unit 350 and the scanner unit 330, and a pair of resin frames 250 that support the sheet metal frames 210 from below. Yes. The scanner unit 330 is screwed to the upper part of the pair of left and right sheet metal frames 210 via a scanner plate (mounting member) (not shown). Accordingly, the scanner unit 330 is horizontally supported between the upper portions of the pair of sheet metal frames 210.

  The lower end edges of the pair of sheet metal frames 210 are in contact with the upper ends of the pair of resin frames 250, respectively. Each resin frame 250 partially extends to the outer side surface of the sheet metal frame 210 that it supports, and is fixed to the sheet metal frame 210 via screws 251. Further, the lower surfaces of the pair of resin frames 250 are connected to each other by screwing a front beam 252 and a rear beam 253 arranged in the front and rear directions.

  Next, FIG. 7 is a perspective view in which a part of the front cover 400 is omitted in FIG. 2, and FIG. 8 is an enlarged perspective view of part A shown in FIG. In the following description, only one of the left and right sides of the respective parts described with reference numerals is sometimes illustrated in the drawing. However, in the printer 100, the respective parts are substantially symmetrical.

  As shown in FIG. 7, a support shaft 352 is inserted in the left-right direction near the front end of the drum subunit 351, and both ends of the support shaft 352 protrude from the left and right side surfaces of the drum subunit 351. When the image forming unit 350 is attached to the frame 200, the support shaft 352 engages with a support shaft insertion hole 211 formed in the front end of the pair of sheet metal frames 210 as shown in FIG. That is, the support shaft insertion hole 211 opens to a flange portion 212 formed by bending the front end of the sheet metal frame 210 outward in the left-right direction and extends rearward, and the lower wall surface 211a is disposed in the horizontal direction, and the lower wall surface 211a. As a result, the front end of the image forming unit 350 is positioned in the vertical direction.

  As shown in FIGS. 3 and 5, a notch 353 is formed at the rear end of the drum subunit 351, which is notched from the rear to the front. When the image forming unit 350 is mounted on the frame 200, the notch 353 engages with the main body reference shaft 220 spanned between the pair of sheet metal frames 210, thereby moving the rear end of the image forming unit 350 up and down. Position in the direction and front-rear direction. Note that a pair of square holes 213 for fixing both ends of the main body reference shaft 220 are formed in the pair of sheet metal frames 210 at positions facing each other, and both ends of the main body reference shaft 220 are located behind the square holes 213. It is urged by a linear spring 230 toward the lower corner.

  The support shaft insertion hole 211 and the square hole 213 described above are simultaneously drilled in the sheet metal frame 210 by a press or the like together with a screw hole (not shown) to which the scanner unit 330 is fixed by a screw. Moreover, the sheet metal frame 210 disposed between each of the screw holes, the support shaft insertion hole 211, and the square hole 213 is configured to have a flat shape without a bent portion. For this reason, in the printer 100, the positional accuracy between the scanner unit 330 and the image forming unit 350 can be secured satisfactorily. As a result, the positional accuracy between the scanner unit 330 and each photosensitive drum 321 is secured favorably. And an accurate image can be formed.

  When the image forming unit 350 is mounted, the drum subunit 351 is guided by a guide (not shown) so that the notch 353 is engaged with the main body reference shaft 220. Since the structure of such a guide is known, for example, from Japanese Patent Application Laid-Open No. 2007-121983, detailed description thereof is omitted here.

  Further, the upper edges of the pair of sheet metal frames 210 are bent outward at a right angle, and a sheet metal scanner cover 241 that covers the front half of the scanner unit 330 from above is screwed to be connected to each other. The belt unit 310 described above is detachably mounted between the pair of resin frames 250.

<Configuration of the main body case>
As shown in FIG. 1, the main body case 40 is made of an injection molded product of a thermoplastic resin, and includes an upper surface cover 41 that covers the upper surface of the frame 200, a side cover 42 that covers both the left and right side surfaces of the frame 200, The rear cover 43 covers the rear surface of the frame 200 and the front cover 400 covers the front surface of the frame 200.

  The top cover 41 is a panel-shaped fixed cover that is screw-fixed to the upper edge of the sheet metal frame 210. A paper discharge tray 41T is recessed behind the top cover 41. The front edge portion of the upper surface cover 41 is a fixed edge 41A that faces a movable edge 400A of the front cover 400, which will be described later, in the front-rear direction. Further, as will be described later with reference to FIG. 15, the extending portion 41 </ b> B extends downward from the fixed edge 41 </ b> A of the upper surface cover 41.

  The left and right side covers 42 are panel-shaped fixed covers that are fixed to the left and right side surfaces of the sheet metal frame 210 with screws.

  The rear cover 43 is a panel-shaped movable cover. Although not shown, the rear cover 43 is pivotally supported so as to be swingable around a lower axis with respect to the rear end edge of the sheet metal frame 210, and can be opened or closed with respect to the top cover 41 and the side cover 42. Has been. Although the rear cover 43 can be a movable cover of the present invention, the present invention is not applied in the present embodiment because it is a portion having little influence on the appearance quality. However, depending on the usage form of the printer 100, the appearance quality of the rear surface may be required. In this case, it is preferable to apply the present invention to the rear cover 43 as well.

<Configuration of the mechanism that interlocks with opening and closing of the front cover and front cover>
Next, the front cover 400 will be described in detail. As shown in FIG. 1, the front cover 400 is a movable cover that is opened or closed with respect to the top cover 41 and the side cover 42. Hereinafter, as indicated by a solid line in FIG. 1, the case where the front cover 400 is closed with respect to the top cover 41 and the side cover 42 is referred to as “when the front cover 400 is closed”. On the other hand, as shown by a two-dot chain line in FIG. 1, the case where the front cover 400 is opened with respect to the top cover 41 and the side cover 42 is referred to as “when the front cover 400 is opened”.

  When the front cover 400 is closed, the front cover 400 has a panel shape that is bent in an inverted “L” shape when viewed in the left-right direction. The upper edge of the front cover 400 (the edge that bends in an inverted “L” shape and extends rearward) is a movable edge 400A that faces the fixed edge 41A of the top cover 41 in the front-rear direction when the front cover 400 is closed. ing.

  As shown in FIGS. 2 and 3, the front cover 400 is provided with a pair of pressed portions 420 projecting rearward on the surface (inner surface) facing rearward when the front cover 400 is closed. Details of the pressed portion 420 will be described later with reference to FIG.

  Further, the front cover 400 is integrally formed with a pair of fan-shaped cam plates 410 that extend from the lower side of the left and right sides toward the rear (that is, toward the sheet metal frame 210). One fan-shaped radius portion of each cam plate 410 is connected to the left and right side edges of the front cover 400. A pair of swinging shafts 411 projecting toward the resin frame 250 side (inward in the width direction) is provided at a portion eccentric from the fan-shaped center of each cam plate 410. On the other hand, a bearing hole 255 is provided in the width direction above the front ends of the pair of resin frames 250 (the bearing hole 255 is enlarged and shown in FIG. 2 only). The bearing hole 255 has a length in the front-rear direction slightly longer than the diameter of the swinging shaft 411, and a length in the vertical direction is ensured in a gap of about 1 to several mm with respect to the diameter of the swinging shaft 411. It is a long slot. For this reason, the oscillating shaft 411 is rotatably inserted into the bearing hole 255 while having a backlash in the vertical direction by being inserted into the bearing hole 255. That is, each cam plate 410 is pivotally supported by each rocking shaft 411 at a portion eccentric from the center of the fan shape. Accordingly, the front cover 400 is pivotally supported with respect to the frame 200 around the axis of the swing shaft 411 via the cam plates 410. When the front cover 400 is closed, as shown in FIGS. 2 and 3, the front cover 400 is disposed substantially vertically and closes between the front edge portions of the pair of sheet metal frames 210. On the other hand, when the front cover 400 is opened, as shown in FIGS. 4 and 5, the front cover 400 is disposed substantially horizontally to expose the image forming unit 350 from between the front edge portions of the pair of sheet metal frames 210. Let

  As shown in FIGS. 7 and 8, the flange portion 212 of each sheet metal frame 210 is formed with two vertically extending through holes 214 at the top and bottom. In the flange portion 212, below the through hole 214, a lock member 500 that slides in the vertical direction with the engagement portion 501 engaged with the through hole 214 is provided. In addition, the lower end of each through-hole 214 is configured to be wider than the other portions in order to insert the engaging portion 501 during assembly.

  As shown in FIG. 7, a chamfered portion 502 is formed at the lower end of the lock member 500 so as to smoothly come into contact with the substantially arc-shaped outer peripheral surface of the cam plate 410. As described above, each cam plate 410 is pivotally supported by each rocking shaft 411 at a portion eccentric from the center of the fan shape. That is, the outer peripheral surface of the cam plate 410 is configured such that the distance from the swinging shaft 411 is shorter as the cam plate 410 is closer to the front cover 400. For this reason, when the cam plate 410 swings while contacting the chamfered portion 502, the lock member 500 moves up and down in accordance with opening and closing of the front cover 400. When the front cover 400 is closed, the lock member 500 is lowered as shown in FIGS. 2 and 3, and when the front cover 400 is opened, the lock member 500 is raised as shown in FIGS. 4 and 5.

  Next, FIG. 9 is a left side view showing the configuration of the printer 100 in a state where the front cover 400 is closed, and FIG. 10 is an enlarged left side view of a portion B shown in FIG. Each lock member 500 is formed with a bottomed hole 510 that is cut out from the inner side in the left-right direction and opened forward in the vicinity of the portion facing the support shaft insertion hole 211 (see FIG. 10). 9 and 10, the outer wall surface of the lock member 500 is partially cut away so that the shape of the bottomed hole 510 becomes clear.

  As shown in FIG. 10, on the lower wall surface of the bottomed hole 510, an inclined surface 511 that is inclined rearward and upward in order from the front is disposed in a horizontal direction so as to be connected to the rear end of the inclined surface 511. A flat surface 512 and a protruding portion 513 protruding in a rectangular shape upward from the rear end of the flat surface 512 are formed. In addition, on the upper wall surface of the bottomed hole 510, a first inclined surface 516 that is slightly inclined rearward and downward in order from the front, and about 45 ° from the rear end of the first inclined surface 516 rearward and upward. The 2nd inclined surface 517 as an example of the press part connected was formed.

  As shown in FIG. 9, a pressing portion 50 that can apply a pressing force to the pressed portion 420 when the front cover 400 is closed is provided on the upper end side of each lock member 500. Since the pressing portion 50 is disposed above the sheet metal frame 210, the pressing portion 50 and the movable edge 400A are in a close positional relationship when the front cover 400 is closed. The pressing part 50 includes a link part 520 and a compression coil spring 530 as an example of an elastic part.

  As shown in an enlarged view in FIG. 15, the link portion 520 is integrally formed with the main body portion 540 of the lock member 500 together with a resin-made U-shaped portion 521 that is curved in a U-shaped cross section. Between the lower surface of the link part 520 and the upper end surface of the main-body part 540, the compression coil spring 530 is arrange | positioned in the up-down direction in the compressed state. The compression coil spring 530 biases the link portion 520 upward from below by its elastic force. Thereby, the link part 520 is pushed by the compression coil spring 530 and can be displaced in the direction from the bottom to the top. In addition, hooks 543 and 523 project from the upper end surface of the main body portion 540 and the lower surface of the link portion 520, respectively, and are engaged with each other, whereby the link portion 520 is pressed by the biasing force of the compression coil spring 530. It is restricted so that it is not displaced too much upward.

  The link portion 520 has a block shape elongated in the front-rear direction. The surface facing the rear side of the link portion 520 is a guide surface 520A that is a plane formed by inclining the horizontal plane backward (in the example of FIG. 15, the inclination angle with respect to the horizontal plane is about 45 °), and its rear edge is U It continues to the character part 521.

  On the other hand, the pressed portion 420 has a block shape that extends in the front-rear direction when the front cover 400 is closed and tapers toward the rear. The flange portion 212 of the sheet metal frame 210 is provided with a through hole 215 that allows the pressed portion 420 to pass therethrough as shown in FIG. 11 described later. When the front cover 400 is closed, the pressed portion 420 is It moves through the through hole 215 to above the link portion 520.

  On the lower surface of the pressed portion 420, a guided surface 420A that is substantially parallel to the guide surface 520A is formed at a position facing the guide surface 520A when the front cover 400 is closed. In addition, a horizontal flat surface 420B and a flat surface 420H that rises in the vertical direction in front of the flat surface 420B and faces rearward are formed on the upper surface on the base side (front) of the pressed portion 420.

  When the front cover 400 is closed, when the pressed portion 420 moves above the link portion 520 while drawing an arc-shaped locus centering on the axis of the swing shaft 411, the upper surface of the link portion 520 and the pressed portion 420 are moved. And the link portion 520 is pushed down one end. When the guided portion 420 moves to a position where the guided surface 420 </ b> A faces the guiding surface 520, the link portion 520 is pushed upward by the urging force of the compression coil spring 530. Then, the guide surface 520 and the guided surface 420 </ b> A come into contact with each other, and the guide surface 520 presses the guided surface 420 with a pressing force F <b> 0 that faces in a direction orthogonal to the guide surface 520. Thereby, the front cover 400 is fixed to the frame 200 in a closed state.

  The pressing force F0 can be broken down into a component force F1 that acts in a direction from bottom to top and a component force F2 that acts in a direction from front to back. The component force F1 of the pressing force F0 displaces the pressed part 420 in the direction from the bottom to the top (corresponding to the first direction of the present invention). The component force F2 of the pressing force F0 displaces the pressed portion 420 in the direction from the front to the rear (corresponding to the second direction of the present invention).

  Here, the upper cover 41 is integrally formed with an extending portion 41B extending downward from the fixed edge 41A. The extending portion 41B has a step shape with respect to the fixed edge 41A, protrudes forward, sinks below the movable edge 400A, protrudes further downward, and has a block shape extending above the link portion 520. . The lower surface of the extending portion 41B is a first contact surface 41G that is a horizontal flat surface. Further, the front surface of the extending portion 41B is a second contact surface 41H that is a flat surface that stands vertically and faces forward.

  For this reason, the pressed portion 420 is brought into contact with the flat surface 420B of the pressed portion 420 that is displaced in the direction from the bottom to the top by the component force F1 of the pressing force F0. Positioned in the direction from bottom to top. The vertical positioning position of the pressed portion 420 by the first contact surface 41G is set so that the vertical step S1 between the upper surface cover 41 and the front cover 400 approaches zero. Further, the pressed portion 420 is brought into contact with the flat surface 420H of the pressed portion 420 that is also displaced in the direction from the front to the back by the component force F2 of the pressing force F0. It is also positioned in the direction from front to back. The positioning position in the front-rear direction of the pressed portion 420 by the second contact surface 41H is set so that the front-rear gap S2 between the top cover 41 and the front cover 400 has a predetermined value that does not impair the appearance quality.

  The pressing part 50 and the pressed part 420 correspond to the engagement mechanism of the present invention. Further, the guide surface 520A and the guided surface 420A correspond to the pressing surface of the present invention.

  Next, FIG. 11 is a perspective view illustrating the configuration of the printer 100 in a state in which the front cover 400 is opened from the upper right upper side, and FIG. 12 is an enlarged perspective view of a portion C illustrated in FIG. 13 is a left side view illustrating the configuration of the printer 100 in a state where the front cover 400 is opened, and FIG. 14 is an enlarged left side view of a portion D illustrated in FIG. 13 and 14 are also shown with a part of the outer wall surface of the lock member 500 cut out, as in FIGS. 9 and 10.

  As shown in FIGS. 12 and 14, when the lock member 500 is lifted by opening the front cover 400, the inclined surface 511 and the flat surface 512 of the bottomed hole 510 protrude from the lower wall surface 211 a of the support shaft insertion hole 211. The upper wall surface 211a is disposed above the lower wall surface 211a. At this time, the upper end of the protruding portion 513 of the bottomed hole 510 is disposed above the upper wall surface 211b of the support shaft insertion hole 211 that is inclined rearward and downward, and the first inclined surface 516 is formed from the upper wall surface 211b. Is also disposed below.

  For this reason, when the front cover 400 is opened and the image forming unit 350 is attached and detached, the inclined surface 511 and the flat surface 512 are disposed above the lower wall surface 211a even if the image forming unit 350 is attached vigorously. Thus, the support shaft 352 does not directly contact the lower wall surface 211a. Further, since the protruding portion 513 is disposed above the upper wall surface 211b, the insertion of the image forming unit 350 in the depth direction is also suppressed by the support shaft 352 coming into contact with the base of the protruding portion 513. The printer 100 is designed so that the notch 353 (see FIG. 3) does not completely engage with the main body reference shaft 220 when the support shaft 352 comes into contact with the base of the protruding portion 513. For this reason, when the image forming unit 350 is inserted, the notch 353 is also restricted from coming into contact with the main body reference shaft 220.

  When the support shaft 352 is on the flat surface 512, the second inclined surface 517 is disposed above the axis of the support shaft 352. For this reason, when the front cover 400 is closed from this state, the second inclined surface 517 is supported by the pressing force transmitted from the pressed portion 420 via the link portion 520 and the compression coil spring 530 as shown in FIG. The shaft 352 is pressed rearward and downward. Further, at this time, the inclined surface 511, the flat surface 512, and the protruding portion 513 are retracted below the lower wall surface 211a. For this reason, the support shaft 352 reliably contacts the lower wall surface 211a of the support shaft insertion hole 211, and the image forming unit 350 is pressed backward as a whole, so that the notch 353 is reliably engaged with the main body reference shaft 220. Therefore, it is possible to reliably position the image forming unit 350 at a predetermined position in the frame 200 and form an accurate image on the paper P.

  As shown in FIG. 10, at this time, there is a gap between the rear wall surface 211 c of the support shaft insertion hole 211 and the support shaft 352, and this is because the notch portion 353 and the main body reference shaft 220 are separated. This is because the rearward movement of the image forming unit 350 is restricted by the engagement. Further, as shown in FIG. 9, at this point in time, the gap is also formed between the chamfered portion 502 of the lock member 500 and the cam plate 410. For this reason, even if some errors occur during manufacturing of the cam plate 410 and the like, the downward movement of the lock member 500 is not limited by the cam plate 410, and the above-described pressing by the second inclined surface 517 can be performed satisfactorily. . Furthermore, since the compression coil spring 530 is inserted between the link portion 520 and the main body portion 540 of the lock member 500, the pressing force from the pressed portion 420 is improved even if creep occurs in the U-shaped portion 521 or the like. It can be transmitted to the second inclined surface 517.

  Next, when the front cover 400 is opened from the state of FIGS. 9 and 10, as described above with reference to FIGS. 13 and 14, the support shaft 352 comes into contact with the upper wall surface 211b to protrude from the protruding portion 513. After rolling down, the flat surface 512 is further lifted above the lower wall surface 211 a of the support shaft insertion hole 211. Therefore, the image forming unit 350 is easily pulled out and attached by being pulled forward, and the photosensitive drum 321 is isolated from the conveying belt 313 by lifting the front end of the image forming unit 350 upward. As is known from Japanese Patent Application Laid-Open No. 2007-121983 and the like, if a guide mechanism is used to move the image forming unit 350 upward when the image forming unit 350 is pulled forward, the photosensitive drum 321 is further layered. It can be reliably isolated from the conveyor belt 313.

<Effect>
According to the printer 100 of the first embodiment, when the front cover 400 serving as a movable cover is closed, the pressing unit 50 causes the component force F1 of the pressing force F0 to be directed upward from the axis side of the lower swing shaft 411. Applying in a certain first direction (hereinafter simply referred to as “first direction”), the pressed portion 420 is displaced in the first direction. Then, the first contact surface 41G of the upper surface cover 41 as a fixed cover contacts the flat surface 420B of the pressed portion 420, whereby the pressed portion 420 is positioned in the first direction, thereby the front cover 400. Is positioned in the first direction. Therefore, even when the front cover 400 is pivotally supported with a backlash between the swing shaft 411 and the bearing hole 255, the step S1 in the first direction between the top cover 41 and the front cover 400 is reduced. Easy to maintain.

  Therefore, according to the printer 100 of the first embodiment, the front cover 400 can be accurately positioned with respect to the top cover 41, and as a result, the appearance of the main body case 40 can be prevented from being deteriorated.

  Further, according to the printer 100, when the front cover 400 is closed, the guide surfaces 520A and 420A formed on the pressed portion 420 and the pressing portion 50 come into contact with each other, so that the component force F1 of the pressing force F0 is the first. In addition to acting in the direction, the component force F2 of the pressing force F0 is also caused to act in a second direction (hereinafter simply referred to as “second direction”) which is a direction from the front to the rear. Then, the movable edge 400A is moved closer to the fixed edge 41A in the second direction by the component force F2 of the pressing force F0. For this reason, the gap S2 in the second direction between the fixed edge 41A and the movable edge 400A can be further reduced.

  Further, the pressing portion 50 includes a compression coil spring 530 and a link portion 520, and the guide surfaces 520A and 420A are formed on the link portion 520, and a plane orthogonal to the first direction (that is, a horizontal plane) is set to the second direction side. And a guided surface 420A formed on the pressed portion 420 and in contact with the guiding surface 520A when the front cover 400 is closed. With this configuration, the component forces F1 and F2 of the pressing force F0 applied by the pressing unit 50 can be applied in the first direction and the second direction without increasing the number of parts.

  Further, the front cover 400 is formed with a movable edge 400A farthest from the axis of the swing shaft 411, and the pressing portion 50 is in a positional relationship close to the movable edge 400A when the front cover 400 is closed. It is arranged. With this configuration, the position where the pressed portion 420 receives the pressing force F0 of the pressing portion 50 can be brought close to the movable edge 400A, so that deformation of the front cover 400 due to the pressing force F0 of the pressing portion 50 is suppressed, and the front surface The positional deviation of the movable edge 400A due to the deformation of the cover 400 can be suppressed.

  Furthermore, according to the printer 100, when the front cover 400 is closed, the second contact surface 41H of the upper surface cover 41 contacts the flat surface 420H facing the second direction of the pressed portion 420, and the front cover 400 is moved to the second surface. Position in the direction. For this reason, it is easy to maintain in a state where the gap S2 in the second direction between the fixed edge 41A and the movable edge 400A is reduced. For this reason, the front cover 400 can be positioned with higher accuracy with respect to the upper surface cover 41, and as a result, the appearance of the main body case 40 can be reliably prevented from being deteriorated.

  Further, in the printer 100, when the front cover 400 is closed, a fixed edge 41A that is a front edge portion of the upper surface cover 41 is adjacent to the movable edge 400A that is the upper edge portion of the front cover 400, and from the fixed edge 41A. An extending portion 41B is extended downward. The first contact surface 41G is provided on the extended portion 41B. With this specific configuration, the movable edge 400A can be accurately positioned with respect to the fixed edge 41A.

  As shown in FIG. 16, instead of providing the second contact surface 41H on the extended portion 41B, the front end surface of the side cover 42 may be an end surface facing forward, as the second contact surface 42E. 16 is an enlarged cross-sectional view of a main part showing a ZZ cross section of FIG. 15. In this case, the second contact surface 42E contacts the rear surface 400H at the left and right edge portions of the front cover 400 and positions the front cover 400 in the second direction (front-rear direction). The same effects as the contact surface 41H can be obtained.

(Example 2)
As shown in FIGS. 17 and 18, the printer of the second embodiment includes the first contact surface 41 </ b> G and the second contact surface 41 </ b> H provided in the extending portion 41 </ b> B of the upper surface cover 41 in the printer 100 of the first embodiment. Instead, the first contact surface 42G and the second contact surface 41H provided on the extending portion 42B of the side cover 42 are employed. Other configurations are the same as those of the printer 100 of the first embodiment. For this reason, the same code | symbol is attached | subjected about the same structure and description is abbreviate | omitted or simplified. Although only the one side in the left-right direction is shown and the other side is not shown, the other side in the left-right direction has the same configuration as the one side.

  In the printer according to the second embodiment, as illustrated in FIG. 17, an extending portion 42 </ b> B that extends inward in the width direction is integrally formed on the front edge portion of the side cover 42 illustrated in FIG. 1. As illustrated in FIG. 18, the extending portion 42 </ b> B has a flat plate shape that faces the back surface (inner surface) facing the rear surface of the front cover 400 with a gap when the front cover 400 is closed.

  The extending portion 42B is formed with a vertically long rectangular opening 42C through which the pressed portion 420 that moves along an arc-shaped locus centering on the axis of the swing shaft 411 is inserted when the front cover 400 is closed. ing.

  Of the upper, lower, left and right inner wall surfaces of the opening 42C, the upper inner wall surface is a first contact surface 42G which is a horizontal flat surface. Further, the front surface of the extended portion 42B and located above the inner wall surface above the opening 42C is a second surface that is a flat surface that rises vertically from the front edge of the first contact surface 42G and faces the front. The contact surface 42H is used.

  When the front cover 400 is closed, the pressed portion 420 passes through the opening 42C and moves to above the link portion 520, and the guide surface 520 presses the guided surface 420 with the pressing force F0. The front cover 400 is fixed in a closed state.

  At this time, the first contact surface 42G comes into contact with the flat surface 420B of the pressed portion 420 that is displaced in the first direction, which is the direction from the bottom to the top, by the component force F1 of the pressing force F0. The pressed part 420 is positioned in the first direction. The positioning position of the pressed portion 420 in the first direction by the first contact surface 42G is set so that the step S1 in the first direction (vertical direction) between the top cover 41 and the front cover 400 approaches zero. Further, due to the component force F2 of the pressing force F0, the second contact surface 42H comes into contact with the flat surface 420H of the pressed portion 420 that is also displaced in the second direction, which is the direction from the front to the back. The pressed part 420 is also positioned in the second direction. The positioning position of the pressed portion 420 in the second direction by the second contact surface 42H is set to a predetermined value such that the gap S2 in the second direction (front-rear direction) between the top cover 41 and the front cover 400 does not impair the appearance quality. Set to

<Effect>
According to the printer of the second embodiment, when the front cover 400 is closed, the first contact surface 42G of the side cover 42 serving as the fixed cover contacts the flat surface 420B of the pressed portion 420, so that the pressed portion 420. Is positioned in the first direction, whereby the front cover 400 is positioned in the first direction with respect to the top cover 42 via the side cover 42. Therefore, even when the front cover 400 is pivotally supported with a backlash between the swing shaft 411 and the bearing hole 255, the step S1 in the first direction between the top cover 41 and the front cover 400 is reduced. Easy to maintain.

  Therefore, according to the printer of the second embodiment, similarly to the printer 100 of the first embodiment, the front cover 400 can be accurately positioned with respect to the side cover 42 and the upper cover 41, and as a result, the appearance of the main body case 40 is improved. It can prevent getting worse.

  Further, according to this printer, when the front cover 400 is closed, the second contact surface 42H of the side cover 42 contacts the flat surface 420H facing the second direction of the pressed portion 420, and the front cover 400 is moved to the second position. Positioning in the direction, thereby positioning the front cover 400 in the second direction with respect to the top cover 42 via the side cover 42. For this reason, it is easy to maintain in a state where the gap S2 in the second direction between the fixed edge 41A and the movable edge 400A is reduced. For this reason, the front cover 400 can be positioned more accurately with respect to the side cover 42 and the top cover 41, and as a result, it is possible to reliably prevent the appearance of the main body case 40 from being deteriorated.

  Furthermore, in this printer, when the front cover 400 is closed, the front edge of the side cover 42 is adjacent to the side edge on the outer side in the width direction of the front cover 400, and the inner side in the width direction from the front edge of the side cover 42. An extending portion 42B extends toward the end. And the 1st contact surface 42G is provided in extension part 42B. With this specific configuration, the movable edge 400A can be accurately positioned with respect to the fixed edge 41A.

  In the above, the present invention has been described with reference to the first and second embodiments. However, the present invention is not limited to the first and second embodiments, and can be appropriately modified and applied without departing from the spirit of the present invention. Needless to say.

  For example, in the first and second embodiments, the direction from the bottom to the top is the first direction and the direction from the front to the back is the second direction, but the first direction and the second direction are not limited to these. In the first and second embodiments, the front cover 400 is a movable cover and the top cover 41 and the side cover 42 are fixed covers. However, the combination of the movable cover and the fixed cover is not limited to these.

  The present invention is applicable to an image forming apparatus.

P: Recording medium (paper)
DESCRIPTION OF SYMBOLS 300 ... Image forming means 200 ... Frame 40 ... Main body case 41, 42 ... Fixed cover (41 ... Top cover, 42 ... Side cover)
411 ... Shaft core (shaft axis)
400 ... Movable cover (front cover)
50, 420 ... engagement mechanism (50 ... pressing part, 420 ... pressed part)
100: Image forming apparatus (printer)
41G ... 1st contact surface 41A ... Fixed edge (front edge part of upper surface cover)
F0: pressing force F1, F2: component force of pressing force (F1: component force in the first direction, F2: component force in the second direction)
520A, 420A ... pressure surface (520A ... guide surface, 420A ... guided surface)
530 ... Elastic part (compression coil spring)
520 ... Link 400A ... Movable edge (upper edge of movable cover)
41H, 42E, 42H ... second contact surface 420H, 400H ... surface facing the second direction of the pressed part or movable cover (flat surface)
41B, 42B ... Extension portion S1 ... Step difference in the first direction between the fixed cover and the movable cover S2 ... Clearance in the second direction between the fixed cover and the movable cover

Claims (7)

Image forming means for forming an image on a recording medium;
A frame that supports the image forming means;
A main body case for storing the image forming means and the frame;
The main body case includes a fixed cover fixed to the frame, a movable cover that is pivotally supported about an axis around the frame or the fixed cover, and is opened or closed with respect to the fixed cover. An image forming apparatus having an engagement mechanism for fixing the movable cover in a closed state with respect to the frame or the fixed cover,
The engagement mechanism is provided on the frame or the fixed cover and can be applied with a pressing force when the movable cover is closed, and is provided on the movable cover and is pressed against the pressing portion when the movable cover is closed. A pressed portion to be
The pressing portion applies the pressing force or a component force of the pressing force in the first direction from the shaft core side, and displaces the pressed portion in the first direction.
The image forming apparatus, wherein the fixed cover is formed with a first contact surface that contacts the pressed portion when the movable cover is closed and positions the movable cover in the first direction. The fixed cover is formed with a fixed edge facing the movable cover in a second direction that intersects the first direction and is perpendicular to the axis when the movable cover is closed,
The pressing portion and the pressed portion are pressed against each other so that a component force of the pressing force is applied in the second direction, and the movable cover approaches the fixed edge in the second direction. The image forming apparatus according to claim 1, wherein a surface is formed. The pressing portion includes an elastic portion that generates the pressing force, and a link that is positioned on a distal end side in the first direction with respect to the elastic portion, and that is pressed by the elastic portion and can be displaced in the first direction. And
The pressing surface is formed on the link portion, and is formed on a guide surface formed by inclining a plane orthogonal to the first direction toward the second direction, and on the pressed portion, and when the movable cover is closed, The image forming apparatus according to claim 2, further comprising a guided surface that contacts the guide surface. The movable cover is formed with a movable edge farthest from the shaft core,
The image forming apparatus according to claim 2, wherein the pressing portion is disposed so as to have a positional relationship close to the movable edge when the movable cover is closed.   The fixed cover is formed with a second contact surface that contacts the surface of the movable cover or the pressed portion facing the second direction when the movable cover is closed, and positions the movable cover in the second direction. The image forming apparatus according to claim 2, wherein the image forming apparatus is an image forming apparatus. The fixed cover is an upper surface cover that covers the upper surface of the main body case, and the movable cover is a front cover that covers the front surface of the main body case,
The said 1st contact surface is provided in the extension part extended toward the downward direction from the front edge part of the said upper surface cover adjacent to the upper edge part of the said movable cover. 2. An image forming apparatus according to item 1. The fixed cover is a side cover that covers the side surface of the main body case, and the movable cover is a front cover that covers the front surface of the main body case,
The first contact surface is provided in an extending portion that extends inward in the width direction from a front edge portion of the side cover adjacent to a side edge portion on the outer side in the width direction of the movable cover. The image forming apparatus according to any one of 1 to 5.

Images