JP2023031749A - Head lock device and image forming apparatus - Google Patents

Abstract

To improve the operability of a head lock device when maintenance of an image forming apparatus is performed.SOLUTION: A head lock device has: a holding member that is movably disposed in an apparatus main body, is cooperated with an exposure device, and places the exposure device at a plurality of positions in association with the movement; and a lock member that is disposed between the holding member and a frame of the apparatus main body to place the exposure device at a lock position where the exposure device is locked. The lock member is urged by an urging member in a direction in which the lock of the exposure device is released. When the exposure device is placed at the lock position, the lock member is urged by the urging member in the direction in which the lock of the exposure device is released, which can thereby improve the operability of the head lock device for locking the exposure device and releasing the lock of the exposure device when maintenance of an image forming apparatus is performed.SELECTED DRAWING: Figure 1

Description

The present invention relates to a headlock device and an image forming apparatus.

2. Description of the Related Art Conventionally, image forming apparatuses such as printers, copiers, facsimile machines, and multi-function machines, such as electrophotographic printers, are provided with an image forming unit, in which the image forming unit is uniformly charged by a charging roller. The surface of the photosensitive drum thus formed is exposed by an LED head as an exposure device to form an electrostatic latent image. The electrostatic latent image is developed with toner to form a toner image. It is designed to be transferred to paper.

Then, the toner image is fixed on the paper by a fixing device provided in the printer, whereby the image is formed and printed (see, for example, Japanese Unexamined Patent Application Publication No. 2002-100003).

JP 2018-159801 A

However, in the conventional printer, when it becomes necessary to perform maintenance of the printer with the LED head moved to a predetermined position, the LED head is locked or unlocked. It is necessary to improve the operability of the headlock device.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a head lock device and an image forming apparatus that can solve the problems of the conventional printer and improve the operability of the head lock device when performing maintenance of the image forming apparatus. and

To this end, in the headlock device of the present invention, there is provided a holding member which is movably disposed within the apparatus main body, is linked with the exposure device, and positions the exposure device at a plurality of positions as it moves; a lock member disposed between the frame of the apparatus main body and for placing the exposure device in a lock position where the exposure device is locked;

Then, the locking member is biased in a direction in which the exposure device is unlocked by the biasing member.

According to the present invention, in the headlock device, a holding member is movably disposed within the device main body, is linked with the exposure device, and positions the exposure device at a plurality of positions as it moves; a lock member disposed between the frame of the apparatus main body and for placing the exposure device in a lock position where the exposure device is locked;

Then, the locking member is biased in a direction in which the exposure device is unlocked by the biasing member.

In this case, when the exposure device is placed at the lock position, the lock member is biased by the biasing member in a direction in which the exposure device is unlocked. The operability of the head lock device for locking and unlocking the exposure device can be improved.

FIG. 4 is a diagram for explaining a dynamic model of the headlock device according to the embodiment of the invention; 1 is a first perspective view of a printer according to an embodiment of the invention; FIG. FIG. 4 is a second perspective view of the printer according to the embodiment of the invention; 1 is a conceptual diagram of a printer according to an embodiment of the invention; FIG. FIG. 4 is a first perspective view showing the state of the printer when the front cover is opened according to the embodiment of the invention; 1 is a perspective view showing a state of a printer when an image forming unit is detached from an apparatus main body according to an embodiment of the invention; FIG. FIG. 4 is a second perspective view showing the state of the printer when the front cover is opened according to the embodiment of the invention; It is a figure which shows the state of the cooperation mechanism by the side of a left side wall when the front cover is opened in embodiment of this invention. It is a figure which shows the state of the cooperation mechanism by the side of a left side wall when the front cover is closed in embodiment of this invention. FIG. 4 is a perspective view of a main part of a linking mechanism on the left side wall in the embodiment of the present invention; FIG. 4 is an exploded view of the essential parts for explaining how the linkage mechanism on the left side wall is attached to the inner panel according to the embodiment of the present invention; FIG. 4 is a perspective view showing the arrangement state of the head holder in the device main body according to the embodiment of the present invention; FIG. 4 is a perspective view showing the state of the printer when the LED head in the embodiment of the invention is placed at the exposure position; FIG. 4 is a perspective view showing the state of the printer when the LED head is placed at the retracted position according to the embodiment of the invention; 1 is a perspective view of a head holder according to an embodiment of the invention; FIG. FIG. 4 is a front view showing a state in which the LED head is held by a head holder according to the embodiment of the present invention; FIG. 4 is a cross-sectional view showing a state in which the LED head is held by a head holder according to the embodiment of the present invention; It is a front view of a cam in an embodiment of the invention. It is a top view of a cam in an embodiment of the invention. It is a front view of a lock lever in an embodiment of the invention. FIG. 4 is a plan view of a lock lever according to the embodiment of the invention; FIG. 4 is a front view showing the state of the head lock device when the LED head is placed at the exposure position according to the embodiment of the present invention; FIG. 23 is a cross-sectional view taken along the line XX of FIG. 22; FIG. 4 is a front view showing the state of the head locking device when the LED head is placed at the locking position in the embodiment of the invention; FIG. 25 is a YY cross-sectional view of FIG. 24; FIG. 4 is a front view showing the state of the head locking device when the LED head is unlocked according to the embodiment of the present invention; FIG. 27 is a cross-sectional view taken along line ZZ of FIG. 26;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this case, a printer as an image forming apparatus will be described.

2 is a first perspective view of the printer according to the embodiment of the invention, FIG. 3 is a second perspective view of the printer according to the embodiment of the invention, and FIG. 4 is a conceptual diagram of the printer according to the embodiment of the invention. is. 2 and 3, the positive direction of the X-axis is the rearward direction of the printer 10, the negative direction of the X-axis is the frontward direction of the printer 10, the positive direction of the Y-axis is the leftward direction of the printer 10, and the negative direction of the Y-axis is the leftward direction of the printer 10. The direction is the right direction on the printer 10 , the positive Z-axis direction is the upward direction on the printer 10 , and the negative Z-axis direction is the downward direction on the printer 10 .

In the figure, 10 is a printer, Bd is the main body of the printer 10, that is, the apparatus main body, and Cs is a housing that surrounds the apparatus main body Bd as the exterior of the printer 10. FIG.

The housing Cs includes a front wall Wf, a rear wall Wr, a left side wall Ws1 as a first wall member disposed on the left side of the front wall Wf when viewed from the front, and a front wall A right side wall Ws2 as a second wall member and a second side wall disposed on the right side of Wf when viewed from the front, and a top wall Wt are provided.

A front cover Pf is freely openable and closable from the upper half Wfa of the front wall Wf to the front half Wtb of the top wall Wt. A person accesses the apparatus main body Bd, attaches or detaches the image forming unit (developing device) 20 to or from the apparatus main body Bd, attaches the image forming unit (developing device) 20 to the apparatus main body Bd, or takes out the paper P as the medium that caused the jam. , a maintenance/administrator as a second operator of the printer 10 can perform maintenance such as maintenance of each part in the apparatus body Bd. A front panel 22f of the paper cassette 22, which serves as a medium storage section, is arranged so as to be openable and closable on the lower half of the front wall Wf. In this embodiment, cut paper is used as the paper P, but roll paper, fan folding paper, or the like can be used instead of the cut paper.

An operation panel 65 is provided at a portion of the top wall Wt adjacent to the front wall Wf and the right side wall Ws2. The operation panel 65 includes a display unit 66 including an LED screen for displaying the status of the printer 10, and an operation unit 67 including switches and keys for the printer operator to input instructions to the printer 10. . Note that when the operation panel 65 is formed by a touch panel, the operation panel 65 functions as a display section and also as an operation section. A stacker sk as a medium stacking unit is formed from the central portion of the top wall Wt to the back wall Wr. A discharge port Hh1 is formed, and a discharge roller pair 26 as a discharge member is rotatably disposed in the discharge port Hh1.

Further, a top cover Pt is openable and closable at a portion of the top wall Wt adjacent to the left side wall Ws1, and the printer operator can access the inside of the left side wall Ws1 by opening the top cover Pt.

In the housing Cs, the image forming unit 20 and the paper cassette 22 are detachably arranged with respect to the apparatus main body Bd, and the LED head 21 as an exposure device is vertically movable. A transfer roller 24 as a transfer member is rotatably disposed below the image forming unit 20, and a fixing device 25 as a fixing device is disposed adjacent to the image forming unit 20. be done.

The image forming unit 20 includes a main body portion 20a and a toner storage portion 17 as a developer storage portion that stores toner as a developer. A toner storage portion 18 as a developer storage portion is formed below the toner storage portion 17 in the main body portion 20a, and the toner supplied from the toner storage portion 17 is stored in the toner storage portion 18. As shown in FIG.

The image forming unit 20 is rotatably disposed facing the photoreceptor drum 11 as an image bearing member and the photoreceptor drum 11, and adheres toner to the photoreceptor drum 11 to form a toner image as a developer image. , a supply roller 13 as a developer supply member for supplying toner to the development roller 12, and a supply roller 13 as a developer supply member for supplying toner to the development roller 12. A charging roller 14 as a charging device for uniformly charging the surface of the drum 11 is disposed with its tip pressed against the developing roller 12, and thins the toner supplied onto the developing roller 12 to form a toner layer. a developing blade 19 as a developer regulating member, a cleaning blade 15 as a cleaning member for scraping and removing residual toner as a transfer residual developer on the photosensitive drum 11, and the cleaning blade 15; A waste toner transport path 16 is provided as a waste developer transport path for transporting the removed residual toner as waste toner, which is a waste developer.

The LED head 21 is disposed facing the photosensitive drum 11 above the main body 20a, and exposes the photosensitive drum 11 charged by the charging roller 14 based on image data. An electrostatic latent image is formed as a latent image on the surface. The developing roller 12 exposes the photosensitive drum 11 by attaching toner to the electrostatic latent image to form a toner image on the photosensitive drum 11 .

The transfer roller 24 is disposed below the main body 20 a so as to face the photosensitive drum 11 , and transfers the toner image on the photosensitive drum 11 onto the paper P supplied from the paper cassette 22 .

The fixing device 25 includes a heating roller R1 as a first fixing member and a pressure roller R2 as a second fixing member. be. In the fixing device 25, the toner image transferred to the paper P is heated by the heating roller R1 and pressed by the pressure roller R2 to be fixed on the paper P. As shown in FIG.

In FIG. 4, 27 is a sealing member made of a film or the like, and the tip of the sealing member 27 is pressed against the developing roller 12. The sealing member 27 prevents the toner in the toner reservoir 18 from prevent it from leaking out.

The photosensitive drum 11, developing roller 12, supply roller 13, charging roller 14 and transfer roller 24 are rotated in the directions of the arrows.

The paper P in the paper cassette 22 is delivered to the medium transport path Rt1 in the direction of the arrow A by the delivery roller 23, transported by the transport roller m1 as a transport member, and passed between the photosensitive drum 11 and the transfer roller 24 (nip). portion) is conveyed in the direction of arrow B, the toner image is transferred, and the toner image is fixed by the fixing device 25 to form an image. Subsequently, the paper P is transported in the direction of arrow C, discharged in the direction of arrow D (outside the apparatus body Bd) by the discharge roller pair 26 through the discharge port Hh1, and stacked on the stacker sk.

By the way, for example, when the printer operator opens the front cover Pf and attaches or detaches the image forming unit 20 to or from the apparatus main body Bd, the LED head 21 may be accidentally touched or impacted. Then, the LED head 21 is damaged. Therefore, in the present embodiment, as the front cover Pf is opened, the LED head 21 is moved by a linking mechanism 33 (FIG. 8), which will be described later, to the retracted position.

FIG. 5 is a first perspective view showing the state of the printer when the front cover is opened according to the embodiment of the invention, and FIG. 6 is the printer when the image forming unit is removed from the main body of the apparatus according to the embodiment of the invention. 7 is a second perspective view showing the state of the printer when the front cover is opened according to the embodiment of the present invention; FIG. 8 is a perspective view showing the state of the printer when the front cover is opened according to the embodiment of the present invention; FIG. 9 is a diagram showing the state of the linkage mechanism on the left side wall when the front cover is closed according to the embodiment of the present invention; FIG. FIG. 11 is an exploded view of the essential parts for explaining the attachment state of the left wall side linkage mechanism to the inner panel according to the embodiment of the present invention; FIG. 13 is a perspective view showing the state of arrangement of the head holder in the apparatus main body according to the embodiment of the present invention, and FIG. 13 is a perspective view showing the state of the printer when the LED head is placed at the exposure position according to the embodiment of the present invention. 14 is a perspective view showing the state of the printer when the LED head is placed at the retracted position according to the embodiment of the present invention, FIG. 15 is a perspective view of the head holder according to the embodiment of the present invention, and FIG. FIG. 17 is a front view showing a state in which an LED head is held by a head holder according to the embodiment of the present invention, and FIG. 17 is a sectional view showing a state in which the LED head is held by the head holder according to the embodiment of the present invention; 5 to 9, the positive direction of the X-axis is the rearward direction of the printer 10, the negative direction of the X-axis is the frontward direction of the printer 10, the positive direction of the Y-axis is the leftward direction of the printer 10, and the negative direction of the Y-axis is the leftward direction of the printer 10. The direction is the right direction on the printer 10 , the positive Z-axis direction is the upward direction on the printer 10 , and the negative Z-axis direction is the downward direction on the printer 10 .

In the figure, 10 is the printer, Wf is the front wall, Wr is the back wall, Ws1 is the left side wall, Ws2 is the right side wall, Wt is the top wall, Pf is the front cover, Wfa is the upper half of the front wall Wf, Wtb is the top wall. The front half of the wall Wt, Bd is the device main body, 21 is the LED head, 30 is a shielding sheet metal as a protective member, 31 is a predetermined portion of the front cover Pf, and in this embodiment, left and right sides of the upper half Wfa. Protrusions 33 as engaging portions protruding from the edges are provided on the left side wall Ws1 and the right side wall Ws2, respectively, and cooperate to move the LED head 21 in accordance with the operation of the front cover Pf by the printer operator. mechanism.

The blindfold sheet metal 30 extends in the left-right direction and is arranged immovably with respect to the apparatus main body Bd. It covers the exposure unit including the cable (FFC) 53 and protects the LED head 21 and the flexible printing cable 53 held by the head holder 45 .

The left side wall Ws1 and the right side wall Ws2 have a double structure, and cover the inner panels In1 and In2 as the first frames of the device body Bd and the inner panels In1 and In2, respectively, of the device body Bd. The outer panels Ou1 and Ou2 are provided as frames, and the linking mechanism 33 is attached to the inner panels In1 and In2 between the inner panels In1 and In2 and the outer panels Ou1 and Ou2.

Next, the cooperation mechanism 33 will be described.

Note that the linking mechanism 33 provided on the left side wall Ws1 and the linking mechanism 33 provided on the right side wall Ws2 differ only in the shape of a cam 41 that serves as a holding member and as a guided member, which will be described later. 8 to 11, only the linking mechanism 33 provided on the left side wall Ws1 will be illustrated and explained, and the linking mechanism 33 provided on the right side wall Ws2 will be illustrated and described. Description is omitted.

In the present embodiment, when the printer operator opens the front cover Pf, the head holder 45 is moved upward by each linking mechanism 33, and the LED head 21 is moved to a predetermined position behind the blindfold metal plate 30. and protected by a blindfold sheet metal 30.

For this purpose, each of the linking mechanisms 33 includes a cam member 35 as a first linking member disposed movably in the front-rear direction (X-axis direction) with the opening and closing of the front cover Pf, and the movement of the cam member 35. Along with this, a lever member 36 as a second linking member arranged to be swingable with respect to the apparatus main body Bd, and a lever member 36 arranged to extend between the left side wall Ws1 and the right side wall Ws2 of the apparatus main body Bd, The head holder 45 is provided so as to be movable in the vertical direction (Z-axis direction) as the member 36 swings.

The cam member 35 has a cam 41. A contact surface s1 is formed at the front end of the cam 41 to be brought into contact with the projection 31. A shaft groove dt1 as an engaged portion extends from the front end to the rear end of the cam 41. is formed through the shaft groove dt1, and a long hole h1 as a guide portion extending in the vertical direction is formed on the rear end side of the shaft groove dt1. Then, at positions corresponding to the shaft grooves dt1 in the inner panels In1 and In2 of the left side wall Ws1 and the right side wall Ws2, the shaft grooves are protruded toward the outer panels Ou1 and Ou2 at predetermined intervals in the front-rear direction and engaged. A pair of guide shafts ps1, ps2 as members and guide members are formed. The cams 41 are movably arranged along the guide shafts ps1 and ps2, and while the cams 41 are moving, the guide shafts ps1 and ps2 are housed in the shaft grooves dt1.

Therefore, as the guide shafts ps1 and ps2 move within the shaft groove dt1, the cam 41 is guided and the cam member 35 is moved in the front-rear direction. To prevent the guide shafts ps1 and ps2 from coming off the shaft grooves dt1, E-rings eg as fixing members are engaged with the tips of the guide shafts ps1 and ps2 via washers ws as spacers.

The lever member 36 includes a lever 43 having a "<" shape, and a guide shaft ps3 as a locking member that is moved along the long hole h1 is provided at the end of the lever 43 on the cam member 35 side. is formed to protrude toward the cam 41, and a cylindrical sleeve SL1 is formed in the center of the lever 43 so as to protrude toward the inner panels In1 and In2 and the outer panels Ou1 and Ou2. , an elongated hole h2 as a guide portion is formed in the end portion of the lever 43 on the side of the head holder 45 so as to extend radially outward from the sleeve SL1. At a position corresponding to the sleeve SL1 in the inner panels In1 and In2, the swing shaft sh1 supporting the lever member 36 protrudes toward the outer panels Ou1 and Ou2 and passes through the sleeve SL1. are placed. In addition, a torsion spring sp1 as a first biasing member is fitted to a portion of the sleeve SL1 protruding toward the inner panels In1 and In2, and one end of the torsion spring sp1 is attached to a predetermined portion of the lever member 36, The ends are locked at predetermined positions of the inner panels In1 and In2. As a result, the lever member 36 is urged in the direction of arrow E (clockwise direction in FIGS. 8 and 9), and accordingly the cam member 35 is urged forward.

When each cam member 35 is moved in the front-rear direction, the guide shaft ps3 is moved along the long hole h1, and the lever member 36 is swung with respect to the apparatus main body Bd.

As shown in FIGS. 15 to 17, the head holder 45 includes a main body portion 75 formed to extend in the left-right direction, and both ends of the main body portion 75, namely the left side wall Ws1 and the right side wall Ws2. Holding portions 45a and 45b are provided at each end portion so as to hang down from the main body portion 75, and the LED head 21 is accommodated and held in an area Ar1 between the holding portions 45a and 45b.

For this purpose, the holding portions 45a and 45b are provided with locking pieces am1 and am2 formed by hanging down from the main body portion 75, and the LED head 21 has locked portions 21a and 21b formed upright at both ends. Prepare. The LED head 21 is held by the head holder 45 by locking the claws ne1 and ne2 of the locking pieces am1 and am2 to the locked portions 21a and 21b.

Spring seats sph1 and sph2 serving as urging member holders are formed so as to hang down from the holding portions 45a and 45b of the head holder 45 adjacent to the holding portions 45a and 45b closer to the center. A head grounding spring 55 as a second urging member and as a grounding member is disposed in. The head grounding spring 55 grounds the LED head 21 and urges the LED head 21 toward the photosensitive drum 11 (FIG. 4) with a predetermined biasing force.

A pair of holder bosses bs1 and bs2 are formed on the end faces of the holding portions 45a and 45b so as to protrude toward the inner panels In1 and In2 at a predetermined interval. A guide groove dt2 is formed extending in the axial direction).

Therefore, the head holder 45 slides the holder bosses bs1 and bs2 along the guide grooves dt2, and moves one of the holder bosses bs1 and bs2, which is the lower holder boss bs1 in this embodiment, to the above-mentioned length. It is moved vertically while being slid along the hole h2.

When the lever member 36 is swung with respect to the apparatus main body Bd, the holder bosses bs1 are moved along the elongated holes h2, and the head holder 45 moves up and down along the guide groove dt2 behind the blind metal plate 30. direction, and the LED head 21 is moved vertically together with the head holder 45 .

In this embodiment, print data is sent to the printer 10 from a host computer (not shown) as a host device, and the print data is edited in a control unit (not shown) to generate image data. is sent and the LED head 21 is driven. For this purpose, a control board 51 as a board constituting the control section is arranged in the device main body Bd of the printer 10 , and the control board 51 and the LED head 21 are connected via the flexible printing cable 53 . are electrically connected. The flexible printed cable 53 extends backward from the LED head 21 in a curved manner, then curves forward, extends upward, further extends rearward, and is connected to the control board 51 .

Next, the operation of the linking mechanism 33 will be described.

As shown in FIG. 8, when the front cover Pf is opened by the printer operator, the biasing force of the torsion spring sp1 causes the cam member 35 to move forward and the lever member 36 to rotate in the arrow E direction. As a result, the head holder 45 is moved upward, and the LED head 21 is retracted from the exposure position, placed at the retracted position, and covered with the shielding sheet metal 30 at the retracted position as shown in FIG.

Therefore, for example, when the printer operator attaches or detaches the image forming unit 20 to or from the apparatus main body Bd, the LED head 21 is not accidentally touched or impacted. 21 can be prevented from being damaged.

When the front cover Pf is closed, the protrusion 31 moves the cam member 35 backward against the biasing force of the torsion spring sp1, and the lever member 36 is rotated counterclockwise in FIGS. As a result, the head holder 45 is moved downward, and the LED head 21 is placed at the exposure position where the surface of the photosensitive drum 11 (FIG. 4) is exposed, as shown in FIG.

By the way, for example, the maintenance/administrator of the printer 10 removes the exposure unit comprising the head holder 45, the flexible printing cable 53, etc., inspects it, and then installs it again or replaces it for maintenance of the exposure unit. Maintenance of the printer 10 such as maintenance may be performed. In that case, since the maintenance work is complicated, the exposure unit may be damaged if the maintenance work procedure is incorrect.

Therefore, a predetermined position in the moving direction of the LED head 21, in this embodiment, a lock position is set slightly below the exposure position, and a predetermined position between each of the linking mechanisms 33 and the housing Cs is set. In the present embodiment, a headlock device is provided between the inner panels In1 and In2, and the maintenance/administrator activates the headlock device when performing maintenance on the printer 10, thereby enabling the LED head to operate. 21 can be placed in the locked position and locked. Therefore, when the LED head 21 is placed in the lock position and locked, it becomes immovable and is placed in a stable state without moving to an upper retracted position or the like, which simplifies the maintenance work of the exposure unit. become.

Next, the head lock device formed in the linking mechanism 33 on the left side wall Ws1 will be described.

FIG. 1 is a diagram for explaining a dynamic model of the headlock device according to the embodiment of the invention, FIG. 18 is a front view of the cam according to the embodiment of the invention, and 19 is a plane of the cam according to the embodiment of the invention. 20 is a front view of a lock lever according to an embodiment of the present invention; FIG. 21 is a plan view of a lock lever according to an embodiment of the present invention; and FIG. FIG. 23 is a cross-sectional view taken along the line XX of FIG. 22, and FIG. 24 is a head lock when the LED head is placed at the lock position according to the embodiment of the present invention. FIG. 25 is a cross-sectional view YY of FIG. 24; FIG. 26 is a front view showing the state of the head locking device when the LED head is unlocked according to the embodiment of the present invention; FIG. 27 is a ZZ sectional view of FIG. 18 to 27, the positive direction of the X-axis is the rearward direction of the printer 10, the negative direction of the X-axis is the frontward direction of the printer 10, the positive direction of the Y-axis is the leftward direction of the printer 10, and the negative direction of the Y-axis is the leftward direction of the printer 10. The direction is the right direction on the printer 10 , the positive Z-axis direction is the upward direction on the printer 10 , and the negative Z-axis direction is the downward direction on the printer 10 .

In the figure, 33 is a linkage mechanism, 41 is a cam, 43 is a lever, 45 is a head holder, dt1 is a shaft groove, h1 is an elongated hole, 45 is a head holder, In1 is an inner panel, ps1 to 3 are guide shafts, bs1, bs2 is a holder boss, and 71 is a lock lever disposed between the cam and the inner panel In1 and serving as a lock member for placing the LED head 21 (FIG. 8) at the lock position. The cam 41 and lock lever 71 constitute a head lock device for locking the LED head 21 .

The cam 41 is arranged to extend from the front end where the contact surface s1 is formed to the rear end where the long hole h1 is formed. The cam portion 41a, the second cam portion 41b whose width in the height direction is widened from the central portion to the rear end, and the first and second cam portions 41a and 41b are connected at the central portion to change the width. The shaft groove dt1 extends over substantially the entire cam 41 from the front end of the cam 41 to the long hole h1.

The cam 41 is thickened at the first and third cam portions 41a and 41c, and rockably supports the lock lever 71 on the upper surfaces Sa of the first and third cam portions 41a and 41c. For this reason, a support shaft sh2 for supporting the lock lever 71 is formed at a predetermined position on the upper surface Sa, which is the rear end portion of the first cam portion 41a in the present embodiment, so as to protrude upward. be done. A protruding edge eg1 having a semicircular shape for preventing the lock lever 71 from coming off the cam 41 is formed in the front half of the upper end of the support shaft sh2 so as to protrude forward.

23, the lock lever 71 is provided at a predetermined location on the upper surface Sa, in this embodiment, at the edge of the front end portion of the first cam portion 41a on the outer panel Ou1 side (Y-axis positive direction side). A regulation projection 73 is formed as a first regulation portion for regulating the rotation range in the clockwise direction in the upper surface Sa, and in the present embodiment, the rear end of the third cam portion 41c. A restricting protrusion 74 is formed as a second restricting portion for restricting the rotation range of the lock lever 71 in the counterclockwise direction in the drawing.

The restricting protrusion 73 has a flat shape with a predetermined length and height in the front-rear direction, and the restricting protrusion 74 has an "L" shape and has a predetermined length in the front-rear direction. and a rib 74b formed from the protrusion 74a toward the inner panel In1 side of the third cam portion 41c.

The lock lever 71 is made of a resin material and accommodates the support shaft sh2. and a second arm Ap2 extending rearward from the bearing portion 76 along the third cam portion 41c.

The bearing portion 76 includes a support shaft housing hole h3 for housing the support shaft sh2. The support shaft housing hole h3 is formed on the front half side of the support shaft housing hole h3 and is slightly larger than the outer diameter of the support shaft sh2. The lock lever 71 has an inner diameter sufficiently larger than the outer diameter of the support shaft sh2 and is formed on the rear half side of the support portion ha for rockingly supporting the support shaft sh2 and the support shaft housing hole h3. from the support shaft sh2. When the support shaft sh2 is positioned inside the support portion ha, the protruding edge eg1 of the support shaft sh2 and the inner peripheral edge of the support portion ha are engaged with each other, so that the lock lever 71 does not come off the cam 41.

Further, an engaging protrusion 78 is formed at a predetermined position in the length direction of the first arm Ap1, in the vicinity of the front end feg in this embodiment, so as to protrude toward the inner panel In1. The engaging protrusion 78 has a chevron shape, and when the LED head 21 is placed at the locked position, it enters a frame hole h4 formed at a predetermined position in the inner panel In1 and engages with the inner panel In1. be combined.

Therefore, the inclined surface in front of the engaging projection 78 is cut out in an "L" shape to form a cutout portion 81. As shown in FIG. The cutout portion 81 is formed to extend forward and obliquely to the right at a predetermined angle with respect to the inner panel In1, and has an engaging surface Sb that is engaged with the inner peripheral edge of the frame hole h4, and the engaging surface Sb. The contact surface Sc is formed substantially orthogonal to Sb and is brought into contact with the inner panel In1.

Further, when the lock lever 71 is rotated in the clockwise direction in FIG. A regulated portion p1 is formed. The rear end portion of the second arm portion Ap2 is formed of a protrusion formed so as to protrude rearward along the inner panel In1. A regulated portion p2 that is pressed against the regulating protrusion 74 when rotated to regulate the rotation range of the lock lever 71, and a regulated portion p2 that protrudes rearward in parallel with the regulated portion P2. An elastic portion p3 is formed as a third biasing member that is deformed when pressed against the regulating protrusion 74 and pressed against the regulated portion P2.

When the front cover Pf is closed as shown in FIG. 9 and the LED head 21 is placed at the exposure position as shown in FIG. It is brought into contact with the inner panel In1 at a more forward position.

When the maintenance/manager of the printer 10 (FIG. 2) opens the front cover Pf to perform maintenance of the printer 10 such as maintenance of the exposure unit, the LED head 21 is retracted as shown in FIG. placed in position.

When the maintenance/administrator presses the front end feg of the lock lever 71 to move the lock lever 71 and the cam 41 rearward to place the LED head 21 in the lock position, the engaging protrusion 78 is opposed to the frame hole h4. Subsequently, when the maintenance/manager applies an external force to the lock lever 71 to rotate the lock lever 71 counterclockwise in FIG. is caused to enter the frame hole h4. When the maintenance/administrator releases the lock lever 71 while the contact surface Sc is in contact with the inner panel In1, the cam 41 and the lock lever 71 are moved forward by the torsion spring sp1 (FIG. 10). , the inner peripheral edge of the frame hole h4 is pressed against the engaging surface Sb, and the engaging protrusion 78 is engaged with the inner panel In1.

At this time, the elastic portion p3 of the second arm portion Ap2 of the lock lever 71 is deformed and pressed against the regulated portion p2, thereby urging the lock lever 71 clockwise in FIG. However, since a frictional force is generated by pressing the inner peripheral edge of the frame hole h4 against the engagement surface Sb, the engagement protrusion 78 is maintained in engagement with the inner panel In1.

FIG. 1 shows a dynamic model of the headlock device when the engaging projection 78 is engaged with the inner panel In1.

That is, the frictional force generated on the engagement surface Sb is Fd, the axis of the support shaft sh2, that is, the rotation center of the lock lever 71 is E, and the engagement surface Sb of the notch 81 and the contact surface Sc and the angle formed by the engagement surface Sb with the direction perpendicular to the straight line ED connecting the center of rotation E and the intersection D is θ, the friction generated in the direction perpendicular to the straight line ED is The component force Fa of the force Fd is
Fa=Fd×cos θ
become.

Assuming that the length of the straight line ED is Led, a torque Tr1 for rotating the lock lever 71 counterclockwise around the rotation center E is
Tr1=Fa×Led
is generated.

Further, the contact point between the elastic portion p3 and the regulating projection 74 is assumed to be G, and the biasing force of the elastic portion p3 at the contact point G generates a force perpendicular to the straight line EG connecting the rotation center E and the contact point G. is Fg and the length of the straight line EG is Leg, the torque Tr2 for rotating the lock lever 71 clockwise around the rotation center E
Tr2=Fg×Leg
is generated.

Therefore, by setting the rotation center E, the positions of the intersection point D and the contact point G, the angle θ, the shape of the elastic portion p3, etc., so that the torque Tr1 is greater than the torque Tr2, the engagement protrusion 78 is engaged with the inner panel In1. The combined state is maintained, and the state in which the LED head 21 is locked in the lock position is maintained.

When the maintenance/administrator completes the maintenance of the printer 10 and pushes the front end feg of the lock lever 71 further to move the lock lever 71 and the cam 41 slightly rearward, the engagement surface Sb is aligned with the frame hole h4. 27, the lock lever 71 is rotated clockwise by the biasing force of the elastic portion p3. Therefore, the engagement projection 78 is no longer engaged with the inner panel In1, and the lock of the LED head 21 is released.

Thus, in this embodiment, when the LED head 21 is placed at the locked position, the lock lever 71 is urged by the elastic portion p3 in the direction in which the lock of the LED head 21 is released. The operability of the head lock device for locking and unlocking the LED head 21 can be improved when performing maintenance.

Although the printer 10 having one image forming unit 20 has been described in this embodiment, the present invention can also be applied to a printer having a plurality of image forming units.

The printer 10 in the present embodiment is a direct transfer type printer that directly transfers a toner image onto a sheet of paper P. It can also be applied to an intermediate transfer type printer that transfers an image onto a sheet of paper P. FIG.

Furthermore, in the present embodiment, the LED head 21 is adapted to be moved vertically, but the LED head 21 may be arranged rotatably or swingably. can also

Also, the present invention can be applied to image forming apparatuses such as copiers, facsimile machines, and multi-function machines.

It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made based on the gist of the present invention, and they are not excluded from the scope of the present invention.

21 LED head 41 Cam 71 Lock lever Bd Apparatus body In1, In2 Inner panel p3 Elastic part

Claims (6)

(a) a holding member that is movably disposed within the apparatus main body, is linked with the exposure device, and places the exposure device at a plurality of positions as it moves;
(b) a lock member disposed between the holding member and a frame of the apparatus main body for placing the exposure device in a lock position where the exposure device is locked;
(c) A head locking device, wherein the locking member is biased in a direction to unlock the exposure device by a biasing member. 2. A head locking device according to claim 1, wherein said locking member is engaged with said frame when said exposure device is placed in the locked position. 3. A head locking device according to claim 2, wherein said locking member has an engaging projection that engages with an inner peripheral edge of a frame hole formed in said frame. (a) the lock member is rotatably arranged with respect to a support shaft formed on the holding member;
(b) The head locking device according to claim 3, wherein the biasing member is an elastic portion that is deformed as the locking member rotates. (a) the engaging protrusion is formed with an engaging surface to be engaged with the inner peripheral edge of the frame hole;
(b) the torque generated in the lock member by the frictional force between the engaging surface and the inner peripheral edge of the frame hole is larger than the torque generated in the lock member by the biasing force of the biasing member; 5. The headlock device according to claim 4. An image forming apparatus comprising the headlock device according to any one of claims 1 to 5.

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