JP2015227221A - Image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image formation device capable of easing an impact on a paper feeding cassette, which is caused when the paper feeding cassette is inserted into the image formation device, with reliability.SOLUTION: An image formation device includes: a device body 10; a paper feeding cassette 14 which is detachably provided at the device body 10; a slide plate 81 which is provided in the paper feeding cassette 14 so as to move in an attachment/detachment direction of the paper feeding cassette 14, the slide plate 81 in which a portion protruding from the paper feeding cassette 14 may contact with the device body 10; and a spring 82 which is provided between the paper feeding cassette 14 and the slide plate 81 and biases the slide plate 81 in an insertion direction of the paper feeding cassette 14. The slide plate 81 contacts with the device body 10 and moves against the spring 82 as the paper feeding cassette 14 is inserted into the device body 10.

Description

  The present invention relates to an image forming apparatus including a paper feed cassette that is detachably attached to an image forming apparatus main body.

  2. Description of the Related Art Image forming apparatuses such as copying machines and printers are known in which a paper feed cassette is attached to and detached from (inserted into and pulled out from) a cassette storage portion of the main body of the image forming apparatus. In the paper feed cassette, a plurality of sheets are stacked and stored in an aligned state. When the user inserts the paper cassette into the cassette housing and pushes it in, the paper cassette is positioned at the paper feed position by the positioning mechanism. Thus, the sheets in the sheet feeding cassette positioned at the sheet feeding position are picked up one by one by the pick-up roller and conveyed toward the registration roller pair on the downstream side, the image forming unit, and the like.

  In this image forming apparatus, due to the impact when the sheet feeding cassette is positioned by the positioning mechanism, the stacked sheets are displaced and the alignment is lowered, or the sheet regulating member is displaced and the sheet guide during sheet feeding is It may not be performed properly. In such a case, there is a possibility that sheet feeding defects such as skew feeding and jamming may occur on the sheet during sheet feeding.

  The inventions of Patent Documents 1 and 2 alleviate the impact at the time of inserting the paper feed cassette and reduce the above-mentioned paper feed failure. Of these, the invention of Patent Document 1 uses a rack, pinion, motor, etc., and the invention of Patent Document 2 uses an electromagnet or the like, both of which use sensors to perform electrical control. The impact of the paper cassette at the time of insertion is mitigated.

  However, since the inventions of Patent Documents 1 and 2 are complicated in configuration and complicated in electrical control, the invention of Patent Document 3 has a simple structure that does not require electrical control, and paper feeding at the time of insertion. The impact of the cassette is reduced.

  In the invention of Patent Document 3, a sealed space is provided between the rear end surface of the paper feed cassette and the inner wall surface on the cassette housing portion side facing the rear end surface, and the volume is reduced as the paper feed cassette is inserted. I have to. When the volume of the sealed space is reduced (compressed), the reaction force reduces the impact of the paper feed cassette during insertion.

Japanese Patent Laying-Open No. 2005-67892 Japanese Patent Laid-Open No. 2005-200160 JP 2008-46741 A

  However, according to the above-mentioned Patent Document 3, high processing accuracy is required to ensure the sealing property of the sealed space, and when high processing accuracy cannot be ensured, the sealing property is reduced and impact is applied. In some cases, it could not be sufficiently relaxed.

  The present invention provides an image forming apparatus capable of reliably mitigating the impact of a paper feeding cassette during insertion while having a simple configuration that does not require electrical control and does not require particularly high processing accuracy. It is.

  The image forming apparatus according to the present invention includes an apparatus main body, a paper feed cassette that is detachably provided on the apparatus main body, and a paper cassette that is provided on the paper feed cassette so as to be movable in the attaching / detaching direction of the paper feed cassette. The projecting portion includes a contact member that can contact the apparatus main body, and a biasing member that biases the contact member in the insertion direction of the sheet feeding cassette. As the paper feed cassette is inserted into the apparatus main body, the sheet cassette comes into contact with the apparatus main body and moves against the urging member.

  In the image forming apparatus of the present invention, the abutting member comes into contact with the apparatus main body and moves against the urging member as the paper feeding cassette is mounted on the apparatus main body. Thereby, it is possible to mitigate the impact when the sheet feeding cassette is mounted on the apparatus main body and the position is regulated. Furthermore, the shock-absorbing mechanism does not require electrical control and can easily reduce an impact while having a simple configuration having a contact member and a biasing member.

FIG. 3 is a perspective view of the image forming apparatus in a state in which a paper feed cassette is inserted at a paper feed position, as viewed from the upper right and obliquely upward. FIG. 3 is a perspective view of the image forming apparatus in a state in which the paper feed cassette is pulled out to a sheet supply position, as viewed from the upper right side on the front side. FIG. 3 is a diagram of an internal structure of the image forming apparatus as viewed from the front side. It is the perspective view which looked at a paper feed cassette and a buffer mechanism from diagonally upward on the near side. (A) is a figure which shows the retreat limit of the slide board with respect to the side wall of a paper feed cassette, (B) is a figure which similarly shows the advance limit. FIG. 10 is a diagram illustrating a state in which the paper feed cassette is locked at a paper feed position and the slide plate is in contact with the rear wall portion of the cassette housing portion. It is a figure explaining the attachment or detachment operation | movement of the paper feeding cassette with respect to a cassette storage part. It is a figure explaining the difference in the angle of the forward tilt of a paper feed cassette by the difference in the presence or absence of a slide plate. It is a figure explaining the modification of a buffer mechanism.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
An image forming apparatus 1 according to a first embodiment of the present invention will be described with reference to FIGS. 2 to 9 correspond to the directions of arrows A to F shown at the upper left in FIG. In the following, for convenience of explanation, the directions of arrows A to F will be described as corresponding to the front, rear, left, right, upper, and lower in this order.

  First, a schematic configuration of the image forming apparatus 1 will be described with reference to FIGS.

  Here, FIG. 1 is a perspective view of the image forming apparatus 1 in a state where the paper feed cassette 14 is inserted and locked at the paper feed position P1 as viewed from the upper right side obliquely. FIG. 2 is a perspective view of the image forming apparatus 1 in a state in which the paper feeding cassette 14 is pulled out to the sheet supply position P2 as viewed from the upper right side obliquely upward. FIG. 3 is a view of the internal structure of the image forming apparatus 1 as seen from the front side.

  The image forming apparatus 1 includes an image forming apparatus main body 10, a paper feed cassette 14, and a buffer mechanism 80. The image forming apparatus main body 10 refers to the whole of the image forming apparatus 1 excluding the paper feed cassette 14 and the buffer mechanism 80.

  As shown in FIGS. 1 and 2, the image forming apparatus main body 10 is formed in a rectangular parallelepiped shape (box shape). An operation panel 11, a left front door 12, and a right front door 13 are disposed on the front side (front side) of the image forming apparatus main body 10. For example, the operation panel 11 is for the user to specify image forming conditions such as the number of images to be formed and the image quality, and to notify the user of a paper jam or out of toner. The left front door 12 and the right front door 13 are opened and closed when maintenance and inspection of an image forming unit 20 described later and when the developer supply container 24a (see FIG. 3) is attached and detached. Below the left front door 12 and the right front door 13 (FIG. 1), a sheet cassette 14 in which a plurality of sheets S are stacked and stored in an aligned state is viewed from the cassette storage portion R (FIG. 3) and is positioned and locked (set) at the paper feed position P1. The paper feed cassette 14 and the cassette storage unit R will be described in detail later. A positioning mechanism that positions (sets) the paper feed cassette 14 at the paper feed position P1 is well known and is not shown.

  An image reading device 15 is disposed on the upper part of the image forming apparatus main body 10. A sheet S after image formation is located below the image reading device 15 and on the rear side (back side) of the operation panel 11. A paper discharge tray 16 to be discharged is provided.

  As shown in FIG. 3, a door unit 17 is disposed on the left side surface 10 a of the image forming apparatus main body 10. The door unit 17 is supported by the left side surface 10a of the image forming apparatus main body 10 so as to be openable and closable. The door unit 17 is opened in the opening direction with reference to the vertical axis, and is closed in the opposite closing direction. By opening the door unit 17, a sheet conveyance path PT1 and a sheet re-conveyance path PT2 described later can be exposed to remove jammed paper (the sheet S causing the paper jam) or perform maintenance. .

  The image forming apparatus 1 includes a sheet conveyance path PT1 that extends from a paper feed cassette 14 disposed in the lower part of the image forming apparatus main body 10 toward the upper discharge tray 16, and is in the middle of the sheet conveyance path PT1. An image forming unit 20 is provided.

  The image forming unit 20 includes a photosensitive drum 21, a charging roller 22, a laser unit 23, a developing roller 25 of the developing device 24, and a transfer roller 26 that are arranged in almost the order along the rotation direction (clockwise in FIG. 3). And a cleaning device 27. The photosensitive drum 21 is rotationally driven in the direction of the arrow, and the drum surface is uniformly charged by the charging roller 22. The surface of the drum after uniform charging is exposed by the laser unit 23, and the charge of the exposed portion is removed to form an electrostatic latent image.

  The laser unit 23 emits light based on an image signal from the image reading device 15. The image reading device 15 includes a document table glass 28 on which a document D is placed with the image surface facing downward, a freely openable / closable pressing plate 29 that closely contacts the document D with the document table glass 28, and a scanning unit equipped with a light source. 30. The scanning unit 30 reads the image information of the document D while moving in the arrow K direction. The laser unit 23 described above exposes the charged drum surface to form an electrostatic latent image by the laser light L that is on / off controlled based on the image information. The electrostatic latent image is developed as a toner image with toner attached by the developing roller 25. The toner image is conveyed to the transfer nip portion between the photosensitive drum 21 and the transfer roller 26 by the rotation of the photosensitive drum 21.

  On the other hand, the sheet S in the paper feed cassette 14 is picked up by the pickup roller 31 and conveyed, and the registration roller 32 adjusts the timing at which the toner image on the photosensitive drum 21 is conveyed to the transfer nip portion. And conveyed to the transfer nip portion. As a result, the toner image is transferred onto the sheet S by the transfer roller 26. At this time, the transfer residual toner that is not transferred to the sheet S and remains on the photosensitive drum 21 is removed by the cleaning device 27. The photosensitive drum 21 from which the transfer residual toner has been removed is used for the next image formation starting from charging.

  The sheet S after the transfer of the toner image is heated and pressed by a fixing device having a heating roller 33 and a pressure roller 34 pressed against the heating roller 33, whereby the toner image is fixed on the surface. The sheet S after the toner image is fixed is discharged onto the paper discharge tray 16 by the discharge roller 35. The image formation on one side (front surface) of the sheet S is thus completed.

  Here, when images are formed on both surfaces (front surface and back surface) of the sheet S, the sheet re-conveying path PT2 is used. The sheet S having the toner image fixed on the surface thereof is guided to the sheet re-conveying path PT2 by stopping and further rotating the discharge roller 35 before the trailing end of the sheet S finishes passing through the discharge roller 35. The sheet S descends along the sheet re-conveying path PT2, makes a U-turn at the lower end of the sheet re-conveying path PT2, changes its direction upward, and is supplied to the registration roller 32 described above. Then, the image formation (transfer and fixing of the toner image) similar to the image formation on the front surface is performed on the back surface, and then discharged onto the paper discharge tray 16.

  Although the case where the image forming apparatus 1 is an electrophotographic image forming apparatus such as a copying machine or a printer has been described above as an example, the present invention is not limited thereto. For example, the image forming apparatus may be an electrophotographic facsimile, a multifunction peripheral (a copying machine, a printer, and a facsimile multifunction peripheral), or an electrostatic recording image forming apparatus.

  FIG. 4 is a perspective view of the paper feed cassette 14 and the buffer mechanism 80 as viewed obliquely from the front side.

  The paper feed cassette 14 is pulled out to the front side (arrow A direction) and inserted to the rear side (arrow B direction) with respect to the cassette housing portion R (see FIGS. 3 and 7) of the image forming apparatus main body 10. The That is, it is attached and detached in the arrow AB direction. That is, the paper feed cassette 14 is detachably attached to the image forming apparatus main body 10. Further, the sheet S stored in the paper feed cassette 14 is fed in the direction of arrow C shown in FIG.

  As shown in FIG. 4, the paper feed cassette 14 includes a tray-shaped cassette body 50, an intermediate plate 60, and sheet regulating plates 71, 72, and 73.

  Among these, the cassette body 50 has a rectangular bottom 51 on which the sheets S are stacked, and four side walls 52, 53, 54, 55 erected on the peripheral edge of the bottom 51. The side wall 52 is a front side wall, and a grip portion 52a that a user can handle when attaching and detaching the paper feed cassette 14 is formed at the center lower portion in the left-right direction (arrow CD direction). The front side wall 52 is formed larger than the rear side wall 53, and when the paper feed cassette 14 is disposed at the paper feed position P1 (see FIG. 3) of the cassette storage portion R, the cassette attachment / detachment opening R1. It is arranged in the vicinity of

  The side wall 53 is located on the rear side and faces the front side wall 52. At the upper end of the rear side wall 53, guide convex portions 53a that engage with guide grooves (not shown) in the front-rear direction formed in a ceiling surface R4, which will be described later, guide the attachment / detachment operation of the paper feed cassette 14 are provided on the left and right sides. Many are provided along the direction (arrow CD direction).

  The side walls 54 and 55 are right and left side walls that extend in the attaching / detaching direction (arrow AB direction) of the paper feed cassette 14 and face each other. The right side wall 54 has a guide plate 56 to be described later at the rear end portion, and a buffer mechanism 80 is attached via the guide plate 56. At the upper end of the left side wall 55, a paper feed guide 55a for guiding the sheet S fed from the paper feed cassette 14 diagonally upward to the left is formed. A large number of guide ribs 55b facing the paper feeding direction are provided on the upper surface of the paper feeding guide 55a in the front-rear direction (arrow AB direction). These side walls 52 to 55 are arranged in a frame shape on the upper surface of the bottom 51 as a whole, and together with the bottom 51 constitute a space in which a plurality of sheets S are stacked and stored in an aligned state. Yes.

  The intermediate plate 60 is swingably disposed so as to cover the upper part of the left side portion of the bottom 51. The middle plate 60 is formed in a rectangular shape that is long in the front-rear direction (in the direction of the arrow AB), and notches 60a and 60b that are largely cut out in a rectangular shape are formed at the center in the left-right direction on the front and rear sides. ing. These notches 60a and 60b are for enabling the movement of the sheet regulating plates 71 and 72 described later in the front-rear direction. The front end 60c and the rear end 60d on the right end side of the middle plate 60 are loosely engaged with through holes 71a and 72a (not shown) provided in the sheet regulating plates 71 and 72, and swing. Consists of the center. The middle plate 60 can swing in the vertical direction on the left end 60e side, and is inclined in a state of being biased upward by a compression spring (not shown).

  The sheet restricting plate 71 is disposed along the front side wall 52, and the sheet restricting plate 72 is disposed along the rear side wall 53. These sheet restricting plates 71 and 72 are disposed so as to be movable in the front-rear direction, and restrict the opposite edges of the sheets S placed on the bottom 51 of the cassette body 50 in a stacked state. Here, the opposite edges are a left edge and a right edge in the sheet S feeding direction (arrow C direction). That is, the sheet regulating plates 71 and 72 are positioned in the sheet passing width direction of the sheet S. The sheet regulating plates 71 and 72 are connected via an interlocking mechanism 74 (for example, a rack and a pinion), and when one is moved to the front side or the rear side, the other is moved to the rear side or the front side on the contrary. It has become. Thereby, even if the sheet S has a different sheet passing width, the center position in the sheet passing width direction is always constant.

  When the pair of sheet regulating plates 71 and 72 are moved, the user moves the V-shaped size switching knob (not shown) while holding it. When the size switching knob is released when the sheet restricting plates 71 and 72 come to a predetermined position, the tip of the size switching knob is fitted into a hole (not shown) formed in the bottom 51, and the predetermined position is reached. Placed in.

  The sheet regulating plate 73 is disposed on the inner side of the right side wall 54 near the center in the front-rear direction. The sheet regulating plate 73 moves in the direction of the arrow CD in conjunction with the movement of the middle plate 60 described above, and regulates the rear end of the fed sheet S in the feeding direction.

  A guide plate 56 for attaching the buffer mechanism 80 is fixed to the rear end portion of the paper feed cassette 14 described above.

  The buffer mechanism 80, the guide plate 56, and the cassette housing portion R of the image forming apparatus main body 10 will be described with reference to FIGS.

  Here, FIG. 5A is a view showing the retreat limit of the slide plate 81 with respect to the side wall 54 of the paper feed cassette 14, and FIG. 5B is a view showing the advance limit. FIG. 6 is a diagram illustrating a state in which the paper feed cassette 14 is locked at the paper feed position P1 and the slide plate 81 is brought into contact with the rear wall portion R2 of the cassette housing portion R. FIG. 7 is a view for explaining the attaching / detaching operation of the paper feeding cassette 14 with respect to the cassette housing portion R.

  The buffer mechanism 80 includes a slidable slide plate 81 as a contact member and a compression spring 82 as a spring member (biasing member). The slide plate 81 has a height dimension (length in the vertical direction) h1 that is substantially the same as the height dimension h2 of the side wall 54 and is formed in a rectangular shape that is long in the front-rear direction. The front surface of the slide plate 81 faces the right side, and the back surface (the surface that slides on the guide plate 56 described later) faces the left side. The slide plate 81 is formed of, for example, a metal plate.

  The slide plate 81 has a window portion 81a on the front end side in the substantially vertical center, and a guide groove 81b on the rear end side. The window portion 81a penetrates the slide plate 81 in the front and back direction and is formed in a rectangular shape that is long in the front-rear direction. In the vicinity of the peripheral edge on the rear end side of the window portion 81a, a first spring mounting portion 81c is provided so as to face the right side. A distal end portion 82a of a compression spring 82, which will be described later, is attached to the first spring attachment portion 81c. Further, the guide groove 81b penetrates the slide plate 81 in the front and back direction and is formed long in the front-rear direction. A guide pin (first guide portion) 56d protruding from the guide plate 56 on the side wall 54 passes through the guide groove 81b, and guides the movement of the guide groove 81b in the front-rear direction.

  The upper end on the rear end side of the slide plate 81 is an inclination restricting portion 81d. As will be described later, when the paper feed cassette 14 is tilted forward when being pulled out, the front end 14a of the paper feed cassette 14 is ahead of the rear end portion 14a. In addition, it comes into contact with the ceiling surface R4 of the cassette housing portion.

  The guide plate 56 is a plate that guides the sliding operation of the slide plate 81 in the front-rear direction, and is disposed at the rear end portion of the side wall 54 described above. The guide plate 56 is, for example, a metal plate that is longer in the front-rear direction than the slide plate 81, and is fixed to the rear end of the side wall 54. The guide plate 56 has guide rails (second guide portions) 56 a and 56 b extending in the front-rear direction for guiding the upper end and the lower end of the front end side of the slide plate 81. Further, a part of the guide plate 56 is cut and raised to form a second spring mounting portion 56 c that penetrates the window portion 81 a of the slide plate 81. Furthermore, a guide pin 56 d that protrudes through the guide groove 81 b of the slide plate 81 is projected from the rear end side of the guide plate 56.

  As described above, the upper end and the lower end of the slide plate 81 are guided by the guide rails 56 a and 56 b of the guide plate 56. Further, the center in the vertical direction on the rear end side is guided by the guide pin 56 d of the guide plate 56. For this reason, it is possible to slide and move in the front-rear direction (arrow AB direction) with a stable posture. That is, the slide plate 81 can come into contact with the image forming apparatus main body. Note that the guide plate 56 is integrally fixed to the side wall 54, and therefore can be regarded as a part of the side wall 54.

  The compression spring 82 as a spring member is formed between the slide plate 81 and the side wall 54, more specifically, between the first spring mounting portion 81c of the slide plate 81 and the second spring mounting portion 56c of the guide plate 56 on the side wall 54 side. It is arranged in between. The compression spring 82 has a distal end portion 82a attached to the first spring attachment portion 81c and a proximal end portion 82b attached to the second spring attachment portion 56c. As a result, the slide plate 81 is urged rearward with respect to the paper feed cassette 14, and as shown in FIG. The end portion 81 e is protruded rearward from the rear end portion 14 a of the paper feed cassette 14. At this time, the second spring mounting portion 56c described above acts as a stopper with which the front end of the window portion 81a of the slide plate 81 comes into contact.

  As shown in FIG. 3, the cassette housing portion R is provided in the lower part of the image forming apparatus main body 10. The cassette housing portion R is formed in a box shape having a cassette attaching / detaching opening (opening portion) R1 for attaching / detaching the paper feeding cassette 14 on the front side. That is, the cassette housing portion R is positioned at the paper feed position P1 and is engaged with the rear wall portion (rear frame) R2 facing the side walls 53, 54, and 55 of the paper feed cassette 14 in a locked state on the right side. It has a part frame (not shown) and a left side frame R5 (see FIG. 7). Furthermore, a bottom surface R3 (bottom frame) on which the bottom 51 of the paper feeding cassette 14 is rubbed when attached and detached, and a ceiling surface (upper frame) R4 facing the top surface of the paper feeding cassette 14 with a gap J therebetween are provided. Yes.

  Next, the operation of the image forming apparatus 1 configured as described above, mainly the operation of the paper feed cassette 14 will be described.

  As shown in FIGS. 1, 3, and 6, in the image forming apparatus 1, the paper feed cassette 14 is inserted into the cassette storage portion R and is locked at the paper feed position P <b> 1. In the paper feed cassette 14, a plurality of sheets S are stacked and stored in an aligned state. At this time, as shown in FIG. 6, the slide plate 81 of the sheet feeding cassette moves to the front side with the rear end 81e in contact with the rear wall R2. Further, the paper feed cassette 14 is locked at the paper feed position P1 by engaging a positioning member (not shown) protruding in a biased state from the cassette housing portion R at a part thereof. For this reason, when pulling out the paper feed cassette 14 from the cassette housing portion R, a force for retracting the positioning member is required.

  When the user designates image formation from the operation panel 11, only one sheet S in the paper feed cassette 14 is taken out by the pickup roller 31, and then image formation is performed as described above.

  When there is no sheet S in the sheet cassette 14 or when the size of the sheet S is changed, the user pulls the sheet cassette 14 forward from the cassette storage unit R. In the following, a case where the same size sheet S is replenished to the paper feed cassette 14 will be described.

  As illustrated in FIG. 7, the paper feed cassette 14 that has been shifted to the front side from the paper feed position P <b> 1 by being pulled out by the user moves forward (in the direction of arrow A) while sliding on the bottom surface R <b> 3. The slide plate 81 has a rear end portion 81e that is separated from the rear wall portion R2 and protrudes rearward from the rear end portion 14a of the paper feed cassette 14.

  Here, as schematically shown in FIG. 8, when the center of gravity G of the paper feed cassette 14 deviates forward (outward) from the front end of the bottom surface R3, the paper feed cassette 14 and the ceiling surface R4 as described above. Since there is a gap J between and, it tilts forward and downward.

  At this time, the sheet feeding cassette 14 comes into contact with the ceiling surface R4 before the rear end of the sheet feeding cassette 14 with respect to the inclination regulating portion 81d of the sliding plate 81. 7 (refer to the two-dot chain line in FIG. 7), and the forward inclination (the downward inclination) is suppressed to be smaller. Further, the length of the sheet feeding cassette 14 including the slide plate 81 in the front-rear direction is longer than that of the sheet feeding cassette 14A, and the length L applied to the ceiling surface R4 is correspondingly increased. For this reason, even when the paper cassette 14A is pulled out more than the paper cassette 14A, the forward tilt is reduced and it is easy to maintain a stable posture. This facilitates the replenishment (storage) operation of the sheet S in the paper feed cassette 14 when the paper feed cassette 14 is pulled out to the sheet replenishment position P2 (see FIG. 2).

  After the sheet S has been supplied, the sheet cassette 14 is pushed (inserted) in the direction of the arrow B (insertion direction) by the user toward the sheet feeding position P1. At this time, before the paper feeding cassette 14 is positioned at the paper feeding position P1 by the positioning mechanism, first, the rear end portion 81e of the slide plate 81 contacts the rear wall portion R2. Further, when the paper feed cassette 14 is pushed in, the compression spring 82 is further contracted, and the reaction force increases the force for pushing back the paper feed cassette 14. Since this force provides a cushion effect, for example, even when the user inserts the paper feed cassette 14 with an excessive force, the impact when the paper feed cassette 14 is positioned by the positioning mechanism is reduced. . For this reason, the displacement of the sheet S in the sheet feeding cassette 14 due to the impact and the displacement of the sheet regulating plates 71, 72, 73, etc. are suppressed. Thereby, it is possible to prevent sheet feeding failure such as skew feeding or paper jamming of the sheet S at the time of feeding due to deviation of the sheet S or the sheet regulating plates 71, 72, 73, and the like.

  Further, as shown in FIG. 6, in the paper feed cassette 14 arranged at the paper feed position P1, the slide plate 81 is urged to the front side by the rear wall R2, and moves to the front side. For this reason, even when the buffer mechanism 80 including the slide plate 81 is provided, the length in the front-rear direction can be the same as that of the paper feed cassette 14A (see FIG. 8) without the slide plate. There is no need to extend the length in the front-rear direction.

  A buffer mechanism 80A, which is a modification of the buffer mechanism 80 described above, will be described with reference to the schematic diagram of FIG. In the buffer mechanism 80A, the same components as those of the buffer mechanism 80 are denoted by the same reference numerals, and redundant description will be omitted as appropriate.

  The buffer mechanism 80A uses a tension spring 82A instead of the above-described buffer mechanism 80 using the compression spring 82 as a spring member (biasing member).

  The buffer mechanism 80A includes a slide plate 81A and a tension spring 82A as a spring member (biasing member). 81 A of slide plates have the window part 81a and the guide groove 81b similar to the above-mentioned slide plate 81. As shown in FIG. A third spring mounting portion 81f is formed in the vicinity of the front end of the window portion 81a. A fourth spring mounting portion 56e cut and raised from the guide plate 56 passes through the window portion 81a.

  The tension spring 82A is disposed between the third spring mounting portion 81f and the fourth spring mounting portion 56e. Thus, the slide plate 81A is urged rearward with respect to the right side wall 54.

  The action and effect of the buffer mechanism 80A having the tension spring 82A as the spring member are substantially the same as those of the buffer mechanism 80 having the compression spring 82 as the spring member.

  In the above description, the example in which the buffer mechanism 80 and the buffer mechanism 80A are provided at the rear end portion of the right side wall 54 of the sheet feeding cassette 14 has been described. You may make it provide in a part.

  In this case, it is possible to further reduce the impact when the paper feed cassette 14 is locked at the paper feed position P1. Further, when it is provided only on the right side wall 54 of the paper feed cassette 14, the rotational force generated in the paper feed cassette 14 when the slide plate 81 comes into contact with the rear wall R2 can be offset. At this time, the posture of the paper feed cassette 14 can be further stabilized.

  G: center of gravity, P1: paper feeding position, R: cassette housing portion, R1: cassette insertion / removal port, R2: rear wall portion (a part of the cassette housing portion), R3: bottom surface, R4: ceiling surface, S: sheet, 1 DESCRIPTION OF SYMBOLS Image forming apparatus 10 ... Image forming apparatus main body 14 ... Paper feed cassette 51 ... Bottom part 54, 55 ... Side wall 56a, 56b ... Guide rail (second guide part) 56c ... Second spring mounting part 56d ... guide pin (first guide part), 56e ... fourth spring mounting part, 80, 80A ... buffer mechanism, 81, 81A ... slide plate (contact member), 81a ... window part, 81b ... guide groove, 81c ... first 1 spring mounting portion, 81d: inclination regulating portion, 81e: rear end portion (projected portion), 81f: third spring mounting portion, 82: compression spring (spring member, biasing member), 82A: tension spring (spring member) , Biasing member), J: the upper part of the paper feed cassette The gap between the Imen (upper frame).

Claims (3)

The device body;
A paper feed cassette detachably provided in the apparatus main body;
A contact member provided in the paper feed cassette so as to be movable in the attachment / detachment direction of the paper feed cassette, and a portion protruding from the paper feed cassette is capable of coming into contact with the apparatus main body;
A biasing member that biases the contact member in the insertion direction of the paper feed cassette,
The abutting member comes into contact with the apparatus main body and moves against the urging member as the paper feeding cassette is inserted into the apparatus main body.
An image forming apparatus. The contact member is a slide plate that is slidably supported on a side wall that extends in the attachment / detachment direction of the paper feed cassette,
The biasing member is a spring that biases the slide plate in a direction in which the slide plate protrudes from a rear end portion of the side wall.
The image forming apparatus according to claim 1. The apparatus main body has a ceiling surface facing the upper part of the paper feed cassette,
The abutting member is positioned ahead of the rear end of the sheet feeding cassette when the sheet feeding cassette is pulled out and the center of gravity of the sheet feeding cassette is moved outward from the apparatus main body and tilts forward. Having an inclination regulating portion that abuts on the ceiling surface and regulates the inclination,
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.

Images