JP4789150B2 - Paper cassette in image forming apparatus - Google Patents

Description

  The present invention relates to a paper feeding cassette in an image forming apparatus such as a copying machine, a printer, a facsimile, or a composite machine using an electrophotographic method, and particularly referred to as a bottom lock type. The paper placement plate can be locked at the lower position in the removed state, and the paper placed on the paper placement plate is brought into contact with the feed roller when it is mounted on the image forming apparatus body. The present invention relates to an antistatic structure in a paper feed cassette in the image forming apparatus.

  2. Description of the Related Art Image forming apparatuses such as copiers, printers, facsimiles, and composite machines using an electrophotographic system generally include a paper feeding device for feeding paper on which images formed are transferred. In addition, as a paper feeding device, a cassette type device that stores paper and can be detachably attached to the main body of the image forming apparatus is often used.

  On the other hand, the paper on which an image is formed in the image forming apparatus is charged by friction with the paper remaining in the paper feed unit when the paper is sequentially taken out from the paper feed unit such as a paper feed cassette, and the charge is placed on the metal paper. It accumulates on the plate and becomes noise when discharging, adversely affecting the image forming means, causing image defects or the like, and causing paper jams due to double feeding. For this reason, various structures for preventing this charging have been proposed.

  For example, in Patent Document 1, in order to reliably ground the paper push-up plate of the paper feed cassette with a simple configuration, the rotation shaft of the paper push-up plate in the paper feed cassette is fitted into a through hole formed in the side plate. Attached to the cassette case so as to rotate freely, a grounded leaf spring protrudes from the inner surface of the paper cassette mounting part formed on the lower frame of the main body of the image forming apparatus. In this case, the sheet cassette of the image forming apparatus in which the tip of the leaf spring is fitted into the through hole so as to come into contact with the rotation shaft of the paper push-up plate and to directly ground the paper push-up plate is shown. Has been.

  Further, in Patent Document 2, since the ground due to the weight reduction and non-conduction of the sheet feeding cassette is not required, the length of the sheet feeding direction of the middle plate can be reduced to 1 / th of the sheet feeding direction length of the smallest size sheet that can be stacked. By reducing the size to 3 or less, the inner plate is reduced in size and weight, and the inner plate is shortened and the weight of the sheet S applied to the intermediate plate is reduced, so that a non-conductive material (resin etc.) is used for the intermediate plate. An image forming apparatus capable of preventing static electricity generated by sliding between sheets S from being discharged to the middle plate and destabilizing the operation of the apparatus, and eliminating the need to take a ground from the cassette. The cassette is shown.

  Further, in Patent Document 3, in order to prevent an adverse effect on the image formation on the sheet due to the electric charge accumulated in the paper feed cassette, the middle plate of the paper feed cassette is provided with a size detecting means via a compression spring and a ground plate. Is electrically connected. The size detection means detects the size when the arm selected according to the conductive size pushes the size detection sensor via the size detection leaf spring on the apparatus main body side. Then, by forming the arm with a conductive material, electric charges can be discharged from the middle plate to the apparatus main body side through the size detecting means, thereby preventing the generation of noise and causing image formation defects due to noise. An image forming apparatus that can be prevented is shown.

  In Patent Document 4, the electrostatic charge charged in the medium cassette is energized through an unexpected path, causing image quality deterioration as an electrical noise of the image forming apparatus body, inducing malfunction of the apparatus, or To prevent the operator from receiving an electric shock, the first grounding that reaches the grounding point through the recording medium, the mounting plate, the conductive part, and the discharge biasing part on the way to insert the medium cassette into the image forming apparatus main body. After the path is formed and the electrostatic charge already charged on the recording medium is discharged before printing is started and the medium cassette is inserted into the image forming apparatus main body, it passes through the recording medium and medium supply roller to the grounding point. An image forming apparatus is shown in which a second grounding path is formed to discharge static charges generated during printing operation.

JP-A-6-32474 Japanese Patent Laid-Open No. 7-10295 Japanese Patent Laid-Open No. 9-25018 JP 2005-179005 A

  However, in the technique disclosed in Patent Document 1, the tip of the leaf spring is brought into contact with the rotation shaft of the paper push-up plate so that the paper push-up plate is directly grounded, but the paper push-up plate is simply installed. A grounding leaf spring is provided only for this purpose. In addition, the cassette shown in Patent Document 2 can be made of a non-conductive material by forming the entire cassette from a non-conductive material (resin etc.). It is said that it is no longer necessary to ground from the cassette to the ground level because it can be solved, but since the static electricity of the paper remains as it is, we think that it is possible to completely eliminate the occurrence of jams due to double feeding of paper In addition, there is a problem in cost because the entire cassette has to be newly made.

  Further, in the image forming apparatus disclosed in Patent Document 3, a special earth plate is provided for discharging charges, which increases the cost accordingly. In addition, since the image forming apparatus shown in Patent Document 4 also extends the conductive portion from the mounting plate to the back side of the cassette, and makes the conductive portion protruding to the outside and the discharge urging portion contact each other to ground, A stretched conductive part is required, which increases the cost.

  Therefore, in the present invention, an image having an antistatic structure that is simple and advantageous in terms of cost is used by using a conventionally used member without newly installing a special ground member or making a large member conductive. It is an object to provide a paper feed cassette in a forming apparatus.

In order to solve the above problems, the paper feed cassette in the image forming apparatus according to the present invention is:
It has a paper feed cassette configured to be detachable in a storage section formed in the image forming apparatus main body,
The paper feed cassette places a paper on which a toner image formed by an electrophotographic system is transferred, a paper placement plate provided so as to be able to swing around the back side in the paper feed cassette mounting direction, and the paper A first elastic member that urges the loading plate in a direction to push up the loading plate from the bottom of the sheet feeding cassette, and the sheet loading plate is held at the bottom of the feeding cassette, and the sheet feeding cassette is mounted in the image forming apparatus main body. In the paper feed cassette in the image forming apparatus provided with a bottom lock mechanism that releases the holding at
The bottom lock mechanism includes a locking claw for holding the sheet placing plate at the bottom of the sheet cassette, and is provided on a side of the sheet cassette and swings when the sheet cassette is mounted on the storage unit. A lock lever that pushes down the paper placement plate, and a locking portion that is formed of a conductive member and locks the locking claw of the lock lever in a state where the paper placement plate is pushed down to the lowermost portion. A second elastic member that is formed of a conductive member and presses the locking portion in the locking claw locking direction; and is formed of a conductive member and is provided in the image forming apparatus main body; It consists of an unlocking member that moves the latching portion in the latching release direction of the latching claw in the mounted state in the storage unit,
An extending portion formed by forming the sheet placing plate and the first elastic member with a conductive member, and extending to a position where the sheet elastic plate contacts the first elastic member with the member forming the second elastic member. The static electricity generated in the paper is released from the lock release member to the image forming apparatus main body through the first elastic member, the second elastic member, and the engaging portion from the paper placement plate. And

  As described above, the second elastic member is separated from the first elastic member, but the extended portion extended to the position where the second elastic member is brought into contact with the first elastic member by the member forming the second elastic member. In addition, the small engaging portion and the unlocking member are made conductive, and the image forming apparatus is connected to the image forming apparatus from the unlocking member via the first elastic member, the second elastic member, and the engaging portion from the sheet placing plate. By letting it escape to the main body, it is possible to form an antistatic structure in the paper feed cassette with a simple configuration without newly installing a special grounding member or making a large member conductive. It can be a paper feed cassette in an advantageous image forming apparatus.

  The sheet feeding cassette is provided with a restricting portion for locking the extending portion provided on the second elastic member, so that the extending portion is firmly fixed even when there is vibration or the like, and is stably prevented from being charged. Can be done.

  In addition, the paper placement plate lock release member is provided in the locking portion, protrudes out of the paper feed cassette, and cooperates with an unlocked pressed portion that is pressed by the paper placement plate lock release member, The sheet loading plate lock releasing member serves as a sheet loading plate lock releasing member that also serves as a member that restricts the sheet cassette from coming out of the image forming apparatus. Are integrally formed so as to restrict the slipping out of the image forming apparatus, and it is possible to efficiently prevent charging with a small number of parts.

  Further, the sheet cassette is prevented from coming off and the sheet placing plate lock releasing member and the unlocked pressed portion are formed in a triangular shape or a triangular shape with the upper part cut off, and the image forming apparatus of the paper feeding cassette When the main body is mounted, the unlocking pressed portion is located on the back side of the image forming apparatus main body with respect to the sheet feeding plate lock releasing member to prevent the paper feeding cassette from coming off. The paper placement plate lock release member and the unlocked pressed portion are in contact with each other in a triangular shape or a triangular shape with the upper part cut away, and the sheet cassette is prevented from coming off between the inclined surfaces and the static electricity generated in the paper feeding cassette portion is imaged. By letting it escape to the forming device, it is surely prevented from coming off, and the sides of the triangle that are in contact with each other are in surface contact with each other, so that grounding can be performed in a large area.

  Furthermore, it is a preferred embodiment of the present invention that the lock lever is swung to the bottom side of the paper feed cassette and locked, or the first elastic member and the second elastic member are coil springs. .

  As described above, the paper feed cassette in the image forming apparatus of the present invention is simple and forms an antistatic structure in the paper feed cassette without newly installing a special grounding member or making a large member conductive. Thus, it is possible to provide a sheet feeding cassette in an image forming apparatus having an antistatic structure that is structurally simple and advantageous in terms of cost.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

  First, the outline of the present invention will be briefly described. In the present invention, a member that forms a second elastic member used in a bottom lock mechanism that holds a sheet placing plate at the bottom of a sheet feeding cassette, An extension portion is provided to extend the paper placement plate in the paper feed cassette to a position in contact with the first elastic member urging in the direction of pushing up from the bottom of the paper feed cassette, and static electricity generated in the paper is placed on the paper placement The first elastic member and the second elastic member from the plate, the locking portion constituting the bottom lock mechanism, and the sheet cassette provided in the main body of the image forming apparatus are prevented from coming off and the paper placement plate is unlocked. It is made to escape to the main body of the image forming apparatus via the member.

  In addition, the paper cassette that is provided on the main body side is prevented from being detached, the paper placement plate lock releasing member, and the unlocked pressed portion in the locking portion on the paper cassette side have a triangular shape or an upper portion cut off. It is formed in a triangular shape, and when the tops of the two come into contact with each other, the lock of the paper placement plate is released, and when the paper feed cassette is pushed into the image forming apparatus main body, The triangular inclined portion of the plate unlocking member and the triangular inclined portion of the unlocking pressed portion are combined to prevent the sheet feeding cassette from popping out and to be grounded in a large area.

  When pulling out the paper cassette from the main body of the image forming apparatus, the paper cassette is prevented from coming off, the triangular inclined portion of the paper mounting plate unlocking member, and the triangular inclined sides of the unlocking pressed portion The paper cassette can be pulled out without applying a large force, and then the paper placement plate is locked again, so that the paper cassette can form an image with the paper placement plate locked. It can be pulled out of the apparatus body.

  By constructing the antistatic structure in this way, a special grounding member is not newly installed, a large member is not made conductive, and the sheet feeding cassette can be prevented from coming off at the same time, which is simple and advantageous in terms of cost. A sheet feeding cassette having an antistatic structure can be obtained.

  Next, in order to understand the antistatic structure of the paper feed cassette according to the present invention, a schematic configuration of a printer as an image forming apparatus and the paper feed cassette will be described with reference to FIG. The printer shown in FIG. 10 includes a printer main body 10 and a paper feeding device 11 disposed below the printer main body 10. The printer main body 10 includes a rectangular parallelepiped housing 12 made of synthetic resin. Near the center of the housing 12 is a space between a front plate and a rear plate made of a metal plate (not shown) disposed in the housing 12 at a predetermined interval in the front-rear direction (direction perpendicular to the paper surface in FIG. 1). A photosensitive drum 13 is rotatably arranged. The photosensitive drum 13 is driven to rotate by sequentially passing through a charging area, an electrostatic latent image forming area, a developing area, a transfer area, and a cleaning area in a direction indicated by an arrow 14 by a gear transmission (not shown). Around the photosensitive drum 13, a charging corona discharge device 15 is disposed in the charging region, a developing device 17 is disposed in the developing region, a transfer roller 18 as a transfer device is disposed in the transfer region, and a cleaning device 19 is disposed in the cleaning region. Yes.

  The charging corona discharge device 15 charges the photosensitive layer formed on the peripheral surface of the photosensitive drum 13 to a specific polarity. In the illustrated embodiment, the developing device 17 includes a developing roller, a stirring means, and the like disposed in a developing housing that contains a developer composed of a single component toner, and is formed on the peripheral surface of the photosensitive drum 13. The developed electrostatic latent image is developed into a toner image. The transfer roller 18 is rotatably supported by the front and rear side plates and is driven to rotate in a direction indicated by an arrow by a gear transmission (not shown). The cleaning device 19 includes a cleaning fur brush, a cleaning blade, and the like, and removes toner remaining on the peripheral surface of the photosensitive drum 13.

  A light exposure device 16 serving as an electrostatic latent image forming device is disposed in an upper portion of the housing 12, that is, above the photosensitive drum 13. The light exposure device 16 projects laser light based on image information output from, for example, a computer onto the peripheral surface of the photosensitive drum 13 in the electrostatic latent image forming area.

  Also, in the housing 12, a sheet conveyance path 20 formed through the transfer area is provided from the right side to the upper left side in the drawing. A paper feed roller pair 28 and a resist roller pair 29 are disposed on the upstream side of the transfer area in the paper transport path 20. A fixing roller pair 21, a conveying roller pair 22, and a discharge roller pair 23 constituting a fixing device are disposed on the downstream side of the transfer area in the paper conveying path 20.

  A sheet feeding device 11 is disposed below the sheet conveying path 20. The paper feeding device 11 includes a cassette housing portion whose front side in the paper feeding direction (right side in FIG. 10) is opened, and a paper feeding cassette 30 that is detachably attached to the cassette housing portion. The paper feed cassette 30 is provided with a coil spring 32 that pushes up the paper placement plate 31 on which the paper is placed toward the delivery roller 26, and the paper placed on the paper placement plate 31 is brought into contact with the delivery roller 26. The paper is fed toward the paper feed roller pair 28 in cooperation with the roller pair 27.

  In the image forming apparatus main body 10 configured as described above, the charging corona discharge device 15 charges the photosensitive layer of the photosensitive drum 13 to a specific polarity while the photosensitive drum 13 is rotated in the direction indicated by the arrow 14. . Next, a laser light source (not shown) of the light exposure device 16 is formed in an electrostatic latent image forming region between a charging region where the charging corona discharge device 15 is disposed and a developing region where the developing device 17 is disposed. ) Is projected onto the photosensitive drum 13, and an electrostatic latent image corresponding to the image information is formed on the peripheral surface of the photosensitive drum 13. Thereafter, the developing roller of the developing device 17 causes the toner to act on the electrostatic latent image on the photosensitive drum 13 to develop the electrostatic latent image into a toner image. On the other hand, the sheet fed from the sheet feeding cassette 30 by the feeding roller 26 and the separating roller pair 27 is conveyed by the sheet feeding roller pair 28 and temporarily stopped by the registration roller pair 29, and takes time with the photosensitive drum 13. Then, the photosensitive drum 13 and the transfer roller 18 are conveyed to a transfer area facing each other. A toner image formed on the peripheral surface of the photosensitive drum 13 by the action of the transfer roller 18 is transferred to the surface of the sheet conveyed to the transfer area.

  The sheet on which the toner image has been transferred is peeled off from the photosensitive drum 13 and then conveyed to the fixing roller pair 21, and the toner image is heated and fixed on the surface of the sheet by the action of the fixing roller pair 21. The sheet on which the toner image has been fixed is discharged to a sheet discharge unit 24 formed on the housing 12 via a conveyance roller pair 22 and a discharge roller pair 23. On the other hand, the photosensitive drum 13 continues to rotate, and residual toner is removed from the surface of the photosensitive drum 13 by the action of the cleaning device 19.

  The paper cassette 30 will be described with reference to FIG. In the figure, reference numeral 31 denotes a swinging fulcrum 311 provided on both sides (only one of them is shown in FIG. 4) on the back side (lower left in FIG. 4) in the mounting direction of the paper feed cassette 30 to the image forming apparatus main body. The sheet placing plate 31 is provided so as to be swingable. When the sheet feeding cassette 30 is mounted on the image forming apparatus main body 10, the sheet placing plate 31 is substantially equidistant on both sides from the center of the sheet feeding cassette 30. 10 is a coil spring 32 (not shown in FIG. 4; see FIGS. 1 and 3) arranged on a spring seat 321 provided at the position of the image forming apparatus main body in FIG. It is possible to feed the loaded paper one by one.

  Reference numeral 33 denotes a rear end regulating member provided on the back side (lower left in the figure) of the paper feed cassette 30 to adjust the depth according to the size of the paper to be loaded, and 34 denotes the paper placement plate 31. The lock member 34 is a lock member for locking at the bottom of the paper feed cassette 30. As will be described later, the lock member 34 includes a lock plate 341, a lock frame 346, and the like. Reference numeral 352 denotes a restricting portion for restricting an extension portion of a coil spring 35 (not shown in FIG. 4; see FIGS. 1 and 3) mounted in the lock frame 346, and 361 is provided in the sheet feeding cassette 30 described later. This is a paper placement plate push-down projection of the lock lever 36.

  FIG. 1 is a perspective view showing the main parts of the components of the antistatic structure described in the outline of the present invention. 32 is attached to a spring seat 321 having a substantially circular shape, and the paper loading in the paper feeding cassette 30 is performed. This is a coil spring that is a first elastic member that urges the placing plate 31 in a direction in which the placing plate 31 is pushed up from the bottom of the sheet feeding cassette 30.

  Reference numeral 34 denotes a lock member for locking the paper placement plate 31 at the bottom of the paper feed cassette 30. The lock member 34 is a guide portion that slidably holds the lock plate 341, the lock frame 346, and the lock plate 341. 347, and a coil spring 35 as a second elastic member that presses the lock plate 341 toward the side plate of the paper feed cassette 30. The lock member 34 is provided in the vicinity of both side plates of the paper feed cassette 30.

  The coil spring 35 has an extending portion 351 that extends from the end of the coil spring 35 to the spring seat 321 of the coil spring 32, and the extending portion 351 is restricted so as not to move by the restricting portion 352. . The extending portion 351 causes the static electricity generated on the paper described in the above outline to escape to the image forming apparatus main body, the paper placement plate 31, the first elastic member (coil spring 32), and the second elastic member (coil spring 35). ) And a lock member 34 serving as a locking portion, and an antistatic member on the paper feed cassette 30 side is configured. The extending portion 351 may be provided on each lock member provided in the vicinity of both side plates of the paper feed cassette 30, but may be provided on one side.

  FIG. 2 is an enlarged perspective view of the conductive lock plate 341 described above. The lock plate 341 is provided with a triangular unlocked pressed portion 348 having a triangular shape or an upper portion cut out on one side formed in a substantially rectangular shape, and a triangular shape provided on the image forming apparatus main body side to be described later. Alternatively, the triangular paper feed cassette with the upper part cut off and the paper placement plate unlocking protrusion 112 abuts to release the lock of the paper placement plate 31 and the paper feed cassette is mounted on the image forming apparatus main body. When this is done, the sides of the triangles or the triangles with the tops cut off come into contact with each other to prevent them from coming off, and they can be grounded in a large area. Further, the rectangular central portion of the lock plate 341 is a rectangular hole, and each side of the hole has a slope portion, and the sheet placement plate 31 is formed by the slope portion 343 as described later. The locking claw 364 for locking is locked.

  Further, on both sides of the short side of the lock plate 341, the guide portions 347 are held by the guide portions 347 provided on the lock frame 346 by the press of the coil spring 35 and the press by the lock release protrusion 112 on the image forming apparatus main body side. A slide portion 345 and a restriction projection 344 are provided so that the slide portion 345 can be slid without jumping out. Reference numeral 342 denotes a spring receiving member formed in a cylindrical shape for receiving the coil spring 35 described in FIG.

  FIG. 3 is a perspective view showing only the coil spring 35, the coil spring 32, and the lock plate 341 in order to show a connection state between the extension portion 351 extended from the end of the coil spring 35 and the coil spring 32. That is, as described above, the static electricity accumulated on the paper placement plate 31 constituting the paper feed cassette 30 reaches the lock plate 341 from the spring holder 342 via the extending portion 351 of the coil spring 35 from the coil spring 32, and then the image. It escapes to the main body of the forming apparatus.

  FIG. 9 is a perspective view of the sheet feeding unit frame 110 on the image forming apparatus main body side to which the above-described sheet feeding cassette 30 is mounted. The sheet feeding cassette 30 shown in FIG. It is mounted from the upper right to the lower left. In the figure, reference numeral 111 denotes a lever bottom lock shaft 362 constituting a lock lever 36 disposed on the paper feed cassette 30 to be described later, so that the lock lever 36 faces the bottom of the paper feed cassette 30 when the paper feed cassette 30 is attached. A rocking mountain-shaped portion 112 is configured to release the lock of the paper loading plate 31 and to prevent the paper feeding cassette 30 from coming off when the paper feeding cassette 30 is mounted on the paper feeding portion frame 110. It is a plate lock release protrusion, and is formed in a triangular shape with an inclination on the inlet side and the outlet side of the paper feed cassette 30 and with the upper side cut off.

  Therefore, at the entrance side inclination, it slides with one of the triangular shape or the triangular shape with the upper part cut off in the unlocked pressed portion 348 of the lock member 34, and leads to the joint part between the apexes of the unlocking position. In the side inclination, the sheet feeding cassette 30 is further inserted from the joining position at the apex, and the other triangular inclination in the unlocked pressed portion 348 of the lock member 34 and the back side inclination contact each other, and the sheet feeding cassette Prevents 30 jumps out. The mountain-shaped portion 111 and the sheet feeding cassette are prevented from coming off, and the sheet placing plate lock release protrusions 112 are provided on both sides of the sheet feeding unit frame 110.

  FIG. 8 is a partially enlarged perspective view showing an arrangement state of the mountain-shaped portion 111 and the sheet feeding cassette in the sheet feeding unit frame 110 and the sheet loading plate lock release protrusion 112. The mountain-shaped portion 111 has a mountain-shaped top portion on the bottom side of the paper feed cassette 30 and is provided on both sides on the inlet side of the paper feed cassette 30 in the paper feed portion frame 110 on the image forming apparatus main body side. In addition, the sheet loading plate lock release protrusion 112 on the image forming apparatus main body side and the sheet loading plate lock release protrusion 112 lock the sheet loading plate 31 while the sheet feeding cassette 30 is mounted on the sheet feeding unit frame 110. The triangular top or the triangular top with the top cut off is released, and the paper feed cassette 30 is further pushed in, so that the paper feed cassette is prevented from coming off, the paper loading plate unlocking projection 112 is inclined, and the triangular lock It is provided at a position where the inclined portion of the release pressed portion 348 contacts.

  FIG. 5 is a perspective view showing an engagement state between the lock lever 36 and the mountain-shaped portion 111 arranged on the side of the paper feed cassette 30 excluding the frame of the paper feed cassette 30. The lock lever 36 is rotatably disposed on the side portion of the paper feed cassette 30 through the rotation shaft hole 363. When the paper feed cassette 30 is attached to the paper feed unit frame 110, the crest shown in FIG. The shape portion 111 and the lever bottom lock shaft 362 are engaged and pushed down, and the locking claw 364 provided on the lock lever 36 is locked by the lock plate 341, so that the paper loading is integrally formed on the lock lever 36. A placement plate push-down projection 361 locks the paper placement plate 31 on the bottom side of the paper feed cassette 30.

  FIG. 7 is a perspective view showing a state in which a lever bottom lock shaft 362 provided on the lock lever 36 protrudes from a swinging opening 301 provided on a side portion of the sheet feeding cassette 30. Reference numeral 361 denotes the above-described paper-loading plate push-down projection, and the lock lever 36 is fixed to the side of the paper feed cassette 30 so as to be swingable by a screw 365 inserted through the rotation shaft hole 363, and protrudes from the swing opening 301. The lever bottom lock shaft 362 is pushed down by engaging with the mountain-shaped portion 111 shown in FIG. Reference numeral 348 denotes an unlocked pressed portion of the lock plate 341 shown in FIG. 2. As described above, the unlocked pressed portion 348 is pressed by the coil spring 35 and Projects from the opening.

  FIG. 6 (A) shows a state in which the locking claw 364 provided on the lock lever 36 is locked by the lock plate 341 shown in FIGS. 1 and 2 when the lock lever 36 is pushed down. FIG. In FIG. 6A, 36 is a lock lever, 362 is a lever bottom lock shaft, and a locking claw 364 provided on the upper and lower sides of the lock lever 36 in FIG. 6 has a slope 343 provided on the lock plate 341. It has a portion in the same inclination direction as the inclined surface portion 343 so that it can be easily locked by sliding, and the lock lever 36 is pushed down to get over the inclined surface portion 343 of the lock plate 341 to be in an engaged state. The lock plate 341 is pressed by the coil spring 35 in the direction in which the lock pawl 364 is locked by the coil spring 35 as described above.

  When the paper feeding cassette 30 is completely loaded into the paper feeding unit frame 110, the main body frame side paper feeding cassette provided in the main body frame 110 is prevented from being detached, and the apex of the paper placement plate unlocking projection 112 is locked. The top of the unlocked pressed portion 348 of the plate 341 comes into contact, and the lock plate 341 is retracted against the pressing force of the coil spring 35. Therefore, as shown in FIG. 6B, the locking claw 364 provided on the lock lever 36 is released from the lock plate 341 to release the lock, and the paper placement plate 31 is pressed by the pressing force of the coil spring 32. Is pushed away from the bottom of the sheet cassette 30.

  The above is the paper placement plate 31 lock mechanism of the paper feed cassette 30 and the antistatic structure using the lock mechanism. If the process up to the lock of the paper placement plate 31 is described again, the paper supply plate shown in FIG. The paper is placed on the paper placement plate 31 of the paper cassette 30, the paper placement plate push-down protrusion 361 of the lock lever 36 is placed on the paper placement plate 31, and the lock lever 36 resists the pressing force of the coil spring 32. When the sheet is pushed down to the bottom side of the sheet feeding cassette 30, as shown in FIG. 6A, the locking claw 364 provided on the lock lever 36 gets over the slope 343 of the lock plate 341 and is locked. The mounting plate 31 is locked at the bottom of the paper feed cassette 30.

  In this state or even when the paper placement plate 31 on which the paper is placed is not pushed down, that is, the paper placement plate 31 is not locked, the paper feed cassette 30 is fed to the image forming apparatus main body side shown in FIG. 5, the lever bottom lock shaft 362 of the lock lever 36 comes into contact with the mountain-shaped portion 111 and the lock lever 36 is swung around the rotation shaft hole 363 as shown in FIG. Even when the plate 31 is inserted without being locked, the paper loading plate 31 is locked at the bottom of the paper feed cassette 30.

  Then, while the paper feed cassette 30 is completely set in the paper feed unit frame 110 on the image forming apparatus main body side, as shown in FIG. The apex of the sheet placement plate lock release protrusion 112 abuts against the apex of the unlocked pressed portion 348 of the lock plate 341, and the locking claw 364 provided on the lock lever 36 is the lock claw 364. Then, the lock is released, and the paper loading plate 31 is pushed up in the direction away from the bottom of the paper feed cassette 30 by the pressing force of the coil spring 32.

  For this reason, the sheets placed on the sheet placing plate 31 are brought into contact with the delivery roller 26 of FIG. 10, and are taken out one by one along with the image formation and sent. When static electricity is generated by this feeding, the static electricity flows from the sheet placing plate 31 through the coil spring 32 and the extending portion 351 of the coil spring 35 to the lock plate 341 and is in contact with the lock plate 341. This prevents the paper cassette from coming off and allows the paper placement plate lock release protrusion 112 to escape from the image forming apparatus main body.

  As described above, according to the present invention, the sheet cassette is prevented from coming off, the sheet placing plate lock release protrusion 112 and the unlocked pressed portion 348 of the lock member 34 on the sheet cassette 30 side are triangular or upper. When the paper placement plate is unlocked when the tops of the cut triangular shapes contact each other, and the paper feed cassette 30 is pushed into the image forming apparatus main body, the paper feed cassette 30 is prevented from coming off. In addition, the triangular inclined portion of the paper placing plate unlocking protrusion 112 and the triangular inclined portion of the unlocking pressed portion 348 are combined to prevent the paper feeding cassette 30 from popping out and to ground the large area. I can do it.

  When the paper cassette 30 is pulled out from the image forming apparatus main body, the paper cassette is prevented from coming off, the triangular inclined portion of the paper placing plate lock release protrusion 112, and the triangular shape in the unlocked pressed portion 348. By the inclined portions provided on both sides, the paper feed cassette 30 can be pulled out without applying a large force, and then the paper placement plate 31 is locked again. The plate 31 can be pulled out of the image forming apparatus main body in a locked state.

  Therefore, according to the present invention, an antistatic structure in the paper feeding cassette can be configured without a new special grounding member or making a large member conductive, which is simple in structure and advantageous in cost. The sheet feeding cassette in the image forming apparatus having a simple antistatic structure can be obtained.

  According to the present invention, it is possible to provide a paper feed cassette in an image forming apparatus having an antistatic structure that is structurally simple and advantageous in terms of cost.

It is a perspective view of the principal part of the antistatic structure of the paper feed cassette in the image forming apparatus according to the present invention. It is a perspective view of the latching | locking part of a bottom lock mechanism which comprises the antistatic structure of the paper feed cassette in the image forming apparatus which becomes this invention. FIG. 3 is a perspective view showing an engagement state of a first elastic member and a second elastic member, which constitutes an antistatic structure for a paper feeding cassette in the image forming apparatus according to the present invention. It is a perspective view of a paper feed cassette in the image forming apparatus according to the present invention. FIG. 4 is a perspective view of a lock lever constituting a bottom lock mechanism of a paper feed cassette in the image forming apparatus according to the present invention, and a mountain-shaped portion provided on the image forming apparatus main body side that swings the lock lever. Sectional view (A) showing a state in which the lock plate is engaged with the locking claw provided on the lock lever, and a state in which the lock plate is released by the lock release protrusion provided on the image forming apparatus main body side. It is sectional drawing (B) shown. FIG. 6 is a perspective view showing a state in which a lever bottom lock shaft provided on the lock lever protrudes from the side of the sheet feeding cassette. FIG. 6 is a perspective view showing an arrangement state of mountain-shaped portions and lock release protrusions provided on the image forming apparatus main body side. 2 is a perspective view of an image forming apparatus main body side frame on which a paper feed cassette according to the present invention is mounted. FIG. 1 is a schematic cross-sectional view of an image forming apparatus to which a paper feed cassette is mounted.

Explanation of symbols

11 Paper feeder 110 Paper feeder frame 111 Mountain-shaped portion 112 Paper sheet cassette retaining stopper and paper placement plate lock release protrusion 30 Paper feed cassette 301 Swing opening 31 Paper placement plate 311 Swing fulcrum 32 Coil spring 321 Spring Seat 33 Rear end restricting member 34 Lock member 341 Lock plate 342 Spring support 343 Slope 344 Restriction protrusion 345 Slide portion 346 Lock frame 347 Guide portion 348 Unlocked pressed portion 35 Coil spring 351 Extending portion 352 Restricting portion 36 Lock lever 361 Paper placing plate push-down projection 362 Lever bottom lock shaft 363 Rotating shaft hole 364 Locking claw 365 Screw

Claims (5)

It has a paper feed cassette configured to be detachable in a storage section formed in the image forming apparatus main body,
The paper feed cassette places a paper on which a toner image formed by an electrophotographic system is transferred, a paper placement plate provided so as to be able to swing around the back side in the paper feed cassette mounting direction, and the paper A first elastic member that urges the loading plate in a direction to push up the loading plate from the bottom of the sheet feeding cassette, and the sheet loading plate is held at the bottom of the feeding cassette, and the sheet feeding cassette is mounted in the image forming apparatus main body. In the paper feed cassette in the image forming apparatus provided with a bottom lock mechanism that releases the holding at
The bottom lock mechanism is
The paper loading plate is provided with a locking claw for holding the paper loading plate at the bottom of the paper feeding cassette, and is provided on the side of the paper feeding cassette and swings when the paper feeding cassette is mounted on the storage portion. A lock lever that pushes down the plate,
A locking portion that is formed of a conductive member and locks the locking claw of the lock lever in a state in which the paper placement plate is pushed down to the lowest part;
A second elastic member formed of a conductive member and pressing the locking portion in the locking claw locking direction;
An unlocking member that is formed of a conductive member and is provided in the image forming apparatus main body, and moves the latching portion in the latching release direction of the latching claw when the sheet feeding cassette is attached to the storage unit. Become
An extending portion formed by forming the sheet placing plate and the first elastic member with a conductive member, and extending to a position where the sheet elastic plate contacts the first elastic member with the member forming the second elastic member. The static electricity generated in the paper is released from the lock release member to the image forming apparatus main body through the first elastic member, the second elastic member, and the engaging portion from the paper placement plate. A paper feed cassette in the image forming apparatus.   The sheet feeding cassette in the image forming apparatus according to claim 1, wherein the sheet feeding cassette is provided with a restricting portion that locks an extending portion provided in the second elastic member.   The paper placing plate lock releasing member is provided at the locking portion and protrudes out of the paper feeding cassette and cooperates with the unlocked pressed portion that is pressed by the paper placing plate lock releasing member. 3. The image forming apparatus according to claim 1, wherein the sheet cassette serves as a member that prevents the paper cassette from coming out of the image forming apparatus, and serves as a sheet loading plate lock release member. Paper cassette.   The sheet cassette is prevented from coming off and the sheet placing plate lock release member and the unlocked pressed portion are formed in a triangular shape or a triangular shape with the upper part cut off, and the image forming apparatus main body of the paper feed cassette is mounted. In this state, the unlocking pressed portion is located on the back side of the image forming apparatus main body with respect to the sheet loading plate lock releasing member, The mounting plate lock release member and the unlocked pressed portion are in contact with each other in a triangular shape or a triangular shape with the upper part cut away, and the sheet feeding cassette is prevented from coming off between the inclined surfaces and static electricity generated in the paper feeding cassette portion is image forming apparatus The paper feed cassette in the image forming apparatus according to claim 3, wherein   5. The sheet feeding cassette in the image forming apparatus according to claim 1, wherein the first elastic member and the second elastic member are coil springs.

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