JP4590351B2 - Sheet storage device and image forming apparatus - Google Patents

Description

  The present invention relates to a sheet storage device and an image forming apparatus, and more particularly to a device for inserting and storing a sheet in a sheet storage portion.

  Conventionally, there is an image forming apparatus that forms an image on a sheet using an electrophotographic image forming system. Examples of such an image forming apparatus include an electrophotographic printer such as an electrophotographic copying machine, a laser printer, and an LED printer, a facsimile apparatus, a word processor, and a complex machine thereof (multifunction printer or the like).

  Such an image forming apparatus is provided with a sheet feeding device that feeds the sheet stored in the sheet storage device toward the image forming unit. As this sheet feeding apparatus, there are a form using a sheet feeding cassette as an example of a sheet storage apparatus and a form using a multi-feed tray as another example of a sheet storage apparatus.

  In a small / low-cost image forming apparatus, a multi-feed tray is often used because of its high storage capacity and high flexibility that can handle various sheets.

  As a conventional multi-feed tray, it rotates in the vertical direction and regulates the side plate position in the width direction perpendicular to the feeding direction of the stacked sheets and the middle plate for pressing the sheet against the feeding roller. In addition, there are some provided with a width regulating mechanism having a width regulating plate for suppressing the skew of the sheet.

  Since the intermediate plate generally rotates in the vertical direction with the rotation center as a fulcrum, the rotation angle varies between full load and small load. Here, since the fluctuation of the rotation angle has a great influence on the feeding performance, in the multi-feed tray, in order to reduce the fluctuation amount of the rotation angle, the sheet is placed at the rotation center as much as possible to the feeding roller. It is desirable to provide it at a position away from the feeding position where it is pressed.

  In addition, from the viewpoint of suppressing the skew of the sheet, it is desirable that the width restriction mechanism be located as close to the feeding position as possible to restrict the position in the width direction of the sheet. In addition, as such a width regulating mechanism, there are one attached to the main body frame and one attached to the middle plate.

  Here, when the storage capacity is small and the fluctuation of the feeding condition depending on the sheet stacking amount is small, the width regulating mechanism 200 is attached to the main body frame 201 as shown in FIG. Often the configuration is adopted.

  On the other hand, when the difference between the feeding conditions when the sheets are fully loaded and when the sheets are loaded is a problem, it is necessary to increase the distance between the rotation shaft 202a of the intermediate plate 202 and the feeding roller 207 as described above. . As shown in FIG. 7A, when the width regulating mechanism 200 is fixed to the main body frame 201, the intermediate plate 202 cannot overlap the width regulating portion 200. Will be far from the feeding position.

  For this reason, in the case of a multi-feed tray, in order to ensure the feeding performance, a configuration in which the width regulating mechanism 200 is mounted on the middle plate as shown in FIG. When sheets are stored in such a multi-feed tray, the sheets are inserted from the arrow direction.

  However, when the width restricting mechanism 200 is provided on the intermediate plate 202 in this way, the width restricting plate of the width restricting mechanism opens due to an impact or vibration accompanying the vertical movement of the intermediate plate 202. There is a problem that the performance deteriorates. Further, since the moment of inertia increases due to an increase in the mass of the intermediate plate 202 that is a moving body, and the width regulating mechanism 200 having a backlash between parts receives an impact, an impact sound during a feeding operation, etc. There was also a problem that became large.

  In addition, when a user operation unit such as the width regulating mechanism 200 is installed, the intermediate plate 202 needs to withstand loads caused by an operation force other than the rotation direction. There was also a cost increase factor.

  In order to solve such a problem, for example, as shown in FIG. 7A, a slit having a size through which the width regulating plate passes is provided in the intermediate plate 202. Thereby, even when the width regulating mechanism 200 is fixed, the rotation center 202a of the intermediate plate 202 can be moved away from the feeding roller 207 from the front end of the width regulating plate.

  However, when such a slit is provided in the multi-feed tray, the multi-feed tray needs to support various sheets, and the middle plate 202 moves up and down with the feeding operation. There is a problem that the tip of the hook is caught.

  Therefore, in the multi-sheet feeding tray, the sheet stacking portion of the middle plate is positioned downstream in the insertion direction from the front end of the width regulating mechanism, and the rotation center provided upstream from the front end of the width regulating mechanism is a fulcrum. There is one that is provided so as to be rotatable. When feeding sheets, the sheet stacking unit is moved up and down in front of the width regulating mechanism (see, for example, Patent Document 1).

JP 11-29225 A

  By the way, in such a conventional multi-feed tray (sheet storage device), when jam processing or the like is performed, the jam processing or the like may be performed in a state where the sheets stacked on the multi-feed tray are extracted. When the sheet is pulled out in this way, the middle plate rotates upward to a position where the sheet stacking portion comes into contact with the feeding roller 207.

  Here, when the intermediate plate rotates in this way, a large gap is generated between the sheet stacking portion and the width regulating mechanism before the width regulating mechanism. When such a large gap is generated, there is a problem that when the sheet is inserted into the multi-sheet feeding tray after the jam processing is finished, the sheet enters the gap and cannot be properly stored.

  Therefore, the present invention has been made in view of such a current situation, and is capable of satisfying both feeding performance and skew feeding performance, and is capable of storing sheets appropriately and an image forming apparatus. Is intended to provide.

  The present invention provides a sheet storage device including a sheet storage unit into which a sheet is inserted and stored, and a regulating unit that is provided in the sheet storage unit and regulates the position of the end portion in the width direction of the sheet perpendicular to the sheet insertion direction. A sheet stacking portion that is provided in the sheet storage portion and is positioned downstream of the leading end in the sheet insertion direction of the restricting means, and supports the sheet stacking portion, and is provided upstream of the leading end of the restricting means in the sheet insertion direction. An intermediate plate that is rotatable in the vertical direction and has an arm member that is rotatable with the rotation center as a fulcrum; and a sheet stacking portion of the intermediate plate that is provided on a regulating means side end of the sheet stacking portion. And a cover portion extending downward to close a gap generated between the sheet stacking portion and the restricting means when rotated upward on the downstream side of the restricting means.

  As in the present invention, a cover portion extending downward is provided at the end of the sheet stacking portion of the middle plate, and when the sheet stacking portion rotates upward on the downstream side of the restricting portion, the sheet A gap generated between the loading portion and the regulating means is closed. As a result, both the feeding performance and the skew feeding performance can be achieved, and the sheet can be stored appropriately.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a laser beam printer which is an example of an image forming apparatus provided with a sheet storage device according to a first embodiment of the present invention. The laser beam printer 100 includes an image forming unit 40, a feeding unit 50 that feeds a sheet P such as recording paper to the image forming unit 40, a transfer unit 51 that transfers a toner image onto the sheet P, and a transfer unit. A fixing unit 16 for fixing the toner image transferred at 51 to the sheet P is provided.

  Here, the image forming unit 40 exposes the surface of the photosensitive drum 1a and the process cartridge 1 including the photosensitive drum 1a, the developing sleeve 1c, the charging roller 1b, the toner container 1d, and the like onto the photosensitive drum 1a. And a laser scanner 21 for forming an electrostatic latent image. The laser scanner 21 includes a laser light emitting unit (not shown), a rotating polygon mirror 21a, a folding mirror 21b, and the like.

  The feeding unit 50 including the sheet feeding device includes a multi-feed tray 15 that is a sheet storage device that stacks the sheets P, and a sheet feeding that feeds the sheets P on the multi-feed tray one by one. A feeding roller 7 as means is provided.

  The transfer unit 51 is in pressure contact with the photosensitive drum 1a to form a transfer nip, and when the sheet P passes through the transfer nip, the toner image on the photosensitive drum 1a is transferred to the sheet P. It is comprised by the transfer roller 3 to perform. The fixing unit 16 includes a heating roller 16a and a pressure roller 16b that is in pressure contact with the heating roller 16a.

  Next, an image forming operation in the laser beam printer 100 configured as described above will be described.

  When the image forming operation is started, the photosensitive drum 1a first rotates in the direction of the arrow, and is uniformly charged to a predetermined polarity and a predetermined potential by a charging roller 1b fed from a high voltage power source (not shown). Then, laser light is emitted from the laser light emitting unit (not shown) of the laser scanner 21 based on the image information to the photosensitive drum 1a having the surface charged in this manner at a timing described later. Further, this laser light is irradiated through the polygon mirror 21a and the folding mirror 21b, whereby an electrostatic latent image is formed on the photosensitive drum 1a.

  Next, the electrostatic latent image is developed by the toner in the toner container 1d that has been appropriately charged with the rotation of the developing sleeve 1c being supplied onto the photosensitive drum 1a and attached to the electrostatic latent image. And visualized as a toner image.

  On the other hand, the sheet P stacked and stored in the multi-feed tray 15 in parallel with the toner image forming operation is sent out by the feeding roller 7 and then separated and conveyed by the separation pad 8 and the feeding roller 7. Then, it is conveyed to the transfer unit 51. The toner image formed on the photosensitive drum by the transfer unit 51 is transferred to a predetermined position on the sheet P by the transfer roller 3.

  Next, the sheet P onto which the toner image has been transferred in this manner is conveyed to a fixing nip formed by a heating roller 16a and a pressure roller 16b provided in the fixing unit 16, where the unfixed toner image is heated and heated. Pressurized and fixed on the sheet surface. The sheet P on which the toner image has been fixed in this manner is discharged onto the discharge tray 19 by the discharge roller pairs 17 and 18. The untransferred toner remaining on the photosensitive drum 1a without being transferred is stored in the waste toner container 1f by the cleaning blade 1e. Then, the photosensitive drum 1a whose surface has been cleaned repeatedly enters the next image forming process.

  FIG. 2 is a perspective view of the multi-feed tray 15 mounted on the laser beam printer main body 101, and FIG. 3 is a side view thereof.

  2 and 3, reference numeral 15a denotes a multi-feed tray main body constituting a sheet storage unit, 1 denotes a middle plate provided on the multi-feed tray main body 15a so as to be rotatable in the vertical direction, and 2 denotes a multi-feed tray main body. This is a width restricting portion provided so as to face 15a and be movable in the width direction. Reference numeral 3 denotes a guide rail that holds the width restricting portion 2, and reference numeral 12 denotes a manual feed guide mechanism that holds a manually fed sheet P1.

  Note that the width restricting portion 2, which is a restricting means for restricting the position of the end portion in the width direction of the sheet, includes a width restricting plate 2 a that is a restricting member that restricts the side end position of the sheet P, and a stacking surface on which the sheets P are stacked. And a bottom plate 2b. The width restricting portion 2 is mounted on a guide rail 3 provided on the main body frame 5 and is movable in the width direction via the rack mechanism 11.

  The intermediate plate 1 is used for stacking sheets and pressing the stacked sheets against the feeding roller 7, and is rotatably attached to the main body frame 5 via a rotation center 1a. The intermediate plate spring 6 is applied with a force so as to rotate upward.

  The operation of the intermediate plate 1 is restricted by a feeding cam 9 and an intermediate plate cam 10 attached to the intermediate plate 1. In the state shown in FIG. Against the loading position.

  By the way, the intermediate plate 1 includes a sheet stacking portion 1A located on the downstream side of the front end of the width restricting portion 2 in the sheet insertion direction, and a rotatable arm member 4 that supports the sheet stacking portion 1A. Here, as shown in FIG. 3, the rotation center 1a of the middle plate 1 (the arm member 4) is far away from the leading end position of the width regulating plate 2a on the upstream side in the sheet insertion direction, that is, from the feeding roller 7. It is provided at a position far away.

  In this way, by providing the rotation center 1a at a position far away from the feeding roller 7, the rotation radius of the intermediate plate 1 can be increased, and the feeding position at the time of full loading and small loading of the sheet can be increased. Change can be reduced. As a result, paper feeding performance can be ensured.

  Further, the sheet stacking portion 1A of the intermediate plate 1 has a sheet stacking surface near the front end of the width restricting portion 2, and the sheet stacking surface end point of the sheet stacking portion 1A is determined by the bottom plate 2b of the width restricting portion 2. A cover member 13 extending downward from the sheet stacking surface to be formed is provided. Here, the cover member 13 has a gap generated between the sheet stacking portion 1A and the bottom plate 2b of the width restricting portion 2 when the sheet stacking portion 1A of the intermediate plate 1 is rotated upward on the downstream side of the width restricting portion 2. It is for closing. In the present embodiment, the cover member 13 serving as the cover portion has an arc shape centered on the rotation center 1a of the intermediate plate 1 from the sheet stacking surface end point.

  By forming the cover member 13 in such a shape, the intermediate plate 1 rotates without interfering with the bottom plate 2b even if the interval B between the sheet stacking portion 1A and the bottom plate 2b of the width regulating portion 2 is narrow. be able to. Further, the bottom plate 2b and the distance B can be made substantially constant regardless of the rotation angle of the middle plate 1.

  As a result, the setability when inserting and setting sheets into the multi-feed tray 15 is improved, and the space for accommodating the cover member 13 and the locus during operation can be made substantially the same. The space required in the main body can be minimized.

  FIG. 3 is a diagram illustrating a state when the feeding unit 50 is in a sheet setting state. In this case, the bottom plate 2b of the width regulating unit 2 and the sheet stacking unit 1A of the intermediate plate 1 are substantially flush with each other. It has become. In this state, the sheet is inserted and set to the vicinity of the feeding roller 7 as indicated by an arrow.

  Here, if the interval B between the sheet stacking portion 1A of the intermediate plate 1 and the width regulating plate 2a is wide, the leading edge enters between the sheet stacking portion 1A and the width regulating plate 2a when a sheet is set, and the catch occurs. there is a possibility. However, in the present embodiment, by forming the cover member 13 provided at the end of the sheet stacking portion 1A on the side of the width regulating portion to have an arc shape, this interval B can be narrowed and sheet catching can be prevented. Can do. The width of the interval B is desirably 10 mm or less so that the finger of the hand is not caught.

  Next, after the sheet is set in this way, when the laser beam printer 100 starts a printing operation, the feeding roller 7 starts to rotate, and the feeding cam 9 attached coaxially to the feeding roller 7 also starts to rotate. . When the feeding cam 9 rotates in this way, the intermediate plate 1 is released from the restriction by the intermediate plate cam 10 and is rotated upward by the pressure of the intermediate plate spring 6 as shown in FIG. As a result, the sheet bundle 14 stacked on the intermediate plate comes into contact with the feeding roller 7 and is fed into the laser beam printer main body.

  When the feeding operation is completed and the feeding roller 7 makes one revolution, the feeding cam 9 also makes one revolution, and the intermediate plate cam 10 is pushed down by the feeding cam 9 and descends to the sheet setting position. By repeating the above operation, the continuous feeding operation of the multi paper feed tray 15 is performed.

  By the way, when a jam or the like of a sheet occurs in the laser beam printer main body during feeding, when the stacked sheet bundle 14 is pulled out from the multi-feed tray 15 in order to perform jam processing, the feeding unit 50 is shown in FIG. The state shown in (b) of FIG. That is, the sheet stacking unit 1A is in direct pressure contact with the feeding roller 7.

  Here, when the cover member 13 of the intermediate plate 1 is not present, in the configuration in which the rotation center 1a of the intermediate plate 1 is upstream from the tip of the width restricting portion 2, a gap indicated by C in FIG. Is generated between the sheet stacking portion 1 </ b> A and the bottom plate 2 b of the width regulating portion 2.

  However, the gap C between the sheet stacking unit 1A and the width regulating unit 2 is closed by providing the cover member 13 in the sheet stacking unit 1A as in the present embodiment. For this reason, when the sheet is inserted and stored in the multi-feed tray 15 after the jam processing is completed, the sheet does not enter the gap C, and the sheet can be stored appropriately.

  Further, in the state shown in FIG. 4B, the rotation center 1a of the intermediate plate 1 is set so that the angle formed by the cover member 13 of the intermediate plate 1 and the sheet insertion direction shown in FIG. The position is determined. Thus, even when the sheet bundle is forcibly inserted into the back side of the main body in the state shown in FIG. 4B, the direction of the force that the intermediate plate 1 and the cover member 13 receive from the insert is the same as that of the intermediate plate 1. It works in the direction of pushing down. For this reason, excessive force is not applied to the intermediate plate 1 and the cover member 13, and deformation and breakage of the components can be prevented.

  As described above, when the cover member 13 extending downward is provided at the width regulating portion side end of the sheet stacking portion 1 </ b> A of the intermediate plate 1, when the sheet stacking portion 1 </ b> A rotates upward on the downstream side of the width regulating portion 2, The cover member 13 closes the gap C generated between the sheet stacking portion 1A and the width regulating portion 2.

  Thereby, in the multi-feed tray 15 in which the width restricting portion 2 is fixed to the multi-feed tray main body 15a, the rotation center 1a of the intermediate plate 1 (the sheet stacking portion 1A) is width-regulated without reducing usability. It can be provided at a position far away from the tip of the portion 2. As a result, both feeding performance and skew feeding performance can be achieved, and sheets can be appropriately stored in the multi-feed tray 15.

  By the way, in the description so far, the case where the cover member 13 is provided on the intermediate plate 1 has been described, but the cover member may be integrally formed on the intermediate plate 1.

  Next, a second embodiment of the present invention will be described.

  FIG. 5 is a diagram illustrating a configuration of a multi-feed tray as an example of a sheet storage device according to the present embodiment. 5, the same reference numerals as those in FIG. 3 indicate the same or corresponding parts.

  In FIG. 5, reference numeral 1 b denotes a cover portion formed integrally with the width regulating portion side end of the sheet stacking portion 1 </ b> A of the intermediate plate 1. The cover portion 1b is positioned below the sheet stacking surface formed by the sheet stacking portion 1A and the bottom plate 2b of the width restricting portion 2, and from the sheet stacking surface end point of the sheet stacking portion 1A, It has an arc shape centered on the rotation center 1a of the stacking portion 1A).

  FIG. 6A is a diagram illustrating a state of the sheet feeding unit 50 including the multi-sheet feeding tray 15 at the time of sheet feeding. The laser beam printer 100 starts the printing operation as described above. Thus, the feeding roller 7 is rotated, and accordingly, the feeding roller 7 is rotated upward by the pressure of the middle leaf spring 6. As the intermediate plate 1 is lifted in this way, the sheet bundle 13 stacked on the intermediate plate comes into contact with the feeding roller 7 and is fed to the main body.

  On the other hand, when a sheet jam or the like occurs in the main body, and the paper stack 13 stacked for performing the jam processing is removed from the main body, the paper feeding unit 50 is in the state shown in FIG.

  Here, when the cover portion 1b of the intermediate plate 1 is not present, a configuration in which the rotation center 1a of the intermediate plate 1 is upstream of the front end of the width restricting portion 2 in the sheet insertion direction is shown in FIG. A gap C is generated between the intermediate plate 1 and the width restricting portion 2. However, as in the present embodiment, by providing the cover portion 1b integrally with the sheet stacking portion 1A of the intermediate plate 1, there is no gap C between the sheet stacking portion 1A and the width regulating portion 2. No loss of usability.

  Further, in the state shown in FIG. 6B, the rotation center 1a of the intermediate plate 1 is set so that the angle formed by the cover portion 1b of the intermediate plate 1 and the sheet insertion direction shown in FIG. The position is determined. Accordingly, even when the sheet bundle is forcibly inserted into the back side of the main body in the state shown in FIG. 6B, the direction of the force that the intermediate plate 1 and the cover portion 13b receive from the insert is different from that of the intermediate plate 1. It works in the direction of pushing down. For this reason, excessive force is not applied to the intermediate plate 1 and the cover portion 13b, and it becomes possible to prevent deformation and breakage of the components.

  In this manner, by integrally forming the cover portion 13b on the intermediate plate 1, in addition to the effects of the first embodiment described above, the number of parts can be reduced, and the cost can be reduced. .

1 is a diagram illustrating a schematic configuration of a laser beam printer which is an example of an image forming apparatus including a sheet storage device according to a first embodiment of the present invention. FIG. 3 is a perspective view of a multi-feed tray as an example of the sheet storage device. FIG. 4 is a side view illustrating a sheet setting state of the multi-feed tray. (A) is a side view showing a feeding state of the multi-feed tray, and (b) is a side view showing a state in which an intermediate plate is raised and stopped. FIG. 6 is a diagram illustrating a configuration of a multi-feed tray as an example of a sheet storage device according to a second embodiment of the present invention. FIG. 4A is a side view showing a feeding state of the multi-sheet feeding tray, and FIG. 4B is a side view showing a state where an intermediate plate is raised and stopped. (A) is a side view which shows the structure of the thing of a width regulation fixed system of the conventional sheet storage apparatus, (b) is a side view which shows the structure of the thing of a width regulation middle board installation system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Middle plate 1A Sheet | seat stacking part 1a Rotation center 1b Cover part 2 Width control part 2a Width control board 2b Bottom plate 4 Arm member 7 Feed roller 13 Cover member 15 Multi-feed tray 15a Multi-feed tray main body 40 Image forming section 50 Feed unit 100 Laser beam printer C Clearance P Sheet

Claims (6)

In a sheet storage device including a sheet storage unit in which a sheet is inserted and stored,
A restricting means for restricting a position of an end of the sheet in the width direction perpendicular to the sheet insertion direction, provided in the sheet storage unit;
The sheet storage unit is provided in the sheet storage unit and supports the sheet stacking unit and the sheet stacking unit that are located downstream of the front end of the regulation unit in the sheet insertion direction, and is provided upstream of the front end of the regulation unit in the sheet insertion direction. An intermediate plate pivotable in the vertical direction having a pivotable arm member with the pivot center as a fulcrum;
A clearance is formed between the sheet stacking portion and the regulating means when the sheet stacking portion is provided at an end of the sheet stacking portion of the intermediate plate on the downstream side of the regulating means. And a cover portion extending downward to close the sheet storage device.   The restricting means includes a restricting member that restricts the position of the end portion in the width direction of the sheet and a bottom plate that forms a sheet stacking surface together with the sheet stacking portion of the intermediate plate, and the cover portion is located above the sheet stacking portion. 2. The sheet storage device according to claim 1, wherein when the sheet is rotated, a gap generated between the sheet stacking portion and the bottom plate of the restricting unit is closed.   The sheet storage device according to claim 1, wherein the shape of the cover portion is an arc shape centered on the rotation center.   The shape of the cover portion and the position of the rotation center are set so that the angle formed by the cover portion and the sheet insertion direction is 90 ° or more when the intermediate plate is rotated upward. The sheet storage device according to any one of claims 1 to 3.   5. The sheet storage device according to claim 1, wherein the cover unit is provided integrally with the sheet stacking unit. An image, comprising: an image forming unit; a sheet storage device according to any one of claims 1 to 5; and a sheet feeding unit that feeds out a sheet stored in the sheet storage device. Forming equipment.

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