JP2006160471A - Sheet feeder, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the uppermost sheet from protruding into a gap between an already loaded sheet and a side regulation plate, or getting over the side regulation plate, when the uppermost sheet is moved by a pickup roller in contact with the sheets as a sheet cassette is inserted into a device body. <P>SOLUTION: This sheet feeder is provided with the pickup roller 109 movable to approach/separate from the uppermost sheet Pa on the sheet cassette that is put into/taken out of the device main body to feed the uppermost sheet in a crossing direction to the inserting direction, and the side regulation plate 102 to regulate an operator's side end part Pc of the sheet in the putting-in/taking-out direction. On a regulating surface 102a of the side regulation plate 102, a projection 110 is provided to prohibit the operator's side end part Pc of the sheet in the putting-in/taking-out direction from slipping in the sheet thickness direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sheet supply apparatus that supplies a sheet and an image forming apparatus that forms an image on a sheet supplied from the sheet supply apparatus.

  2. Description of the Related Art Conventionally, an image forming apparatus includes a sheet supply device that supplies a sheet to an image forming unit serving as an image forming unit that forms an image on a sheet. Examples of the image forming apparatus include a copying machine, a printer, a facsimile, and a complex machine of these.

  The sheet feeding device includes a sheet cassette on which sheets are stacked and can be taken in and out of the apparatus main body, and among the sheets stacked in the sheet cassette, the uppermost sheet can be contacted and separated from the thickness direction of the sheet, and the uppermost sheet. A pickup roller that contacts the uppermost sheet in a direction intersecting the loading / unloading direction, a side regulating plate provided in a sheet cassette that aligns the front end of the sheet in the loading / unloading direction, and a pickup roller There is a type provided with a control device that separates the uppermost sheet from the uppermost sheet (see Patent Document 1).

  As shown in FIG. 9, such a sheet supply apparatus is configured so that the sheet cassette 1 is moved to the apparatus main body in order to quickly supply the uppermost sheet Pa among the sheets P stacked on the sheet cassette 1. In the middle of being inserted in the direction, the pickup roller 2 is lowered to contact the uppermost sheet Pa.

  However, the uppermost sheet Pa is prevented from moving by the distance L1 by the pickup roller 2, and may be received and bent by the moving side regulating plate 3.

  In order to eliminate the bending of the sheet, the control apparatus moves the pickup roller 2 from the uppermost sheet Pa at least once after the sheet cassette 1 is inserted into the apparatus main body until the pickup roller 2 starts supplying the sheet. They were separated to release the deflection.

JP-A-9-226949

  However, in the conventional sheet supply apparatus, there may be a gap G between the side regulating plate 3 as the aligning means and the already stacked sheets P. When the gap G is generated, when the uppermost sheet is received by the side regulating plate 3 and bent, the uppermost sheet may enter the gap G as indicated by the solid line of the symbol Pa1. In particular, this phenomenon is likely to occur in a low-back seat. Even if the gap G is not generated, the stiff sheet sometimes runs on the side regulating plate 3 as indicated by the broken line indicated by symbol Pa2.

  As described above, the sheet that has entered the gap G or the sheet that has ridden on the side regulating plate 3 remains displaced even if the pickup roller 2 is once separated from the uppermost sheet. 1 was sent out, and jammed downstream.

  Further, the image forming apparatus provided with the conventional sheet conveying device that may cause jamming has a low image forming operation rate.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet feeding apparatus that prevents a sheet from entering a gap between a sheet already stacked and the aligning unit or climbing onto the aligning unit.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that includes a sheet supply device that supplies a sheet so that a jam does not occur on the sheet and has an improved image forming operation rate.

  In order to achieve the above object, the sheet feeding apparatus according to the present invention is capable of contacting and separating a sheet stacking unit on which sheets are stacked and put in and out of the apparatus main body, and a topmost sheet stacked on the sheet stacking unit. And a sheet supply means for sending out the uppermost sheet in a direction crossing the direction of taking in and out of the sheet stacking means, and the sheet supply after the sheet stacking means is inserted into the apparatus main body. In the sheet feeding apparatus, wherein the sheet stacking unit is separated from the uppermost sheet before the unit starts feeding the sheet, the sheet stacking unit includes a front end of the sheet in the loading / unloading direction of the sheet stacking unit. And a matching member that aligns the sheets of the alignment member to prevent the front end of the sheet from sliding in the thickness direction of the sheet. Characterized in that a slip means for.

  In order to achieve the above object, an image forming apparatus of the present invention includes the above-described sheet supply device and an image forming unit that forms an image on a sheet supplied from the sheet supply device.

  This before the sheet feeding operation is a timing after the sheet stacking unit is mounted on the apparatus main body, and may be immediately after the sheet stacking unit is mounted, immediately after the apparatus is turned on, or immediately before the pickup operation is started.

  The shifted uppermost sheet slides while the uppermost sheet is in contact with the sheet supply unit, so that the shift of the sheet end (the front side where the sheet stacking unit is pushed in) is suppressed by the alignment member. Therefore, the uppermost sheet forms a loop between the sheet supply unit and the alignment member. After the sheet stacking means is set, the shifted uppermost sheet tries to return to the original position by the repulsive force of the loop by separating the sheet supply means from the paper surface of the uppermost sheet. Since the position of the paper width is regulated by the aligning member, the uppermost sheet moves to a position where there is no deviation due to the repulsive force of canceling the loop.

  In addition, the alignment member is provided with a protruding member that hooks the end of the paper so that a loop can be surely formed when the uppermost sheet shifted to the alignment member is pressed.

  A sheet supply apparatus according to an embodiment of the present invention and a copier as an image forming apparatus including the sheet supply apparatus will be described with reference to the drawings. Examples of the image forming apparatus include a copying machine, a printer, a facsimile, and a complex machine of these. For this reason, the image forming apparatus is not limited to a copying machine.

(Copier)
FIG. 1 is a cross-sectional view taken along the sheet conveying direction of the copying machine. In the copying machine 201, a known image reading device 203 and an automatic document feeder 204 are mounted on an upper portion of an apparatus main body 202. The automatic document feeder 204 is provided at the top of the image reading device 203 so that it can be opened and closed with the back side as the opening and closing center.

  The automatic document feeder 204 automatically supplies a document to the image reading device 203 with the upper portion of the image reading device 203 closed. When the automatic document feeder 204 is opened, the copying machine 201 places a document, a book, a magazine, etc. (document etc.) on a document table glass (not shown) provided on the upper part of the image reading device 203, and reads the document, etc. Be able to. Note that the automatic document feeder 204 is not necessarily provided.

  The surface of the photosensitive drum 211 as image forming means in the apparatus main body 202 is charged by a charger 212 while rotating in the direction of the arrow. The laser scanner 213 irradiates the photosensitive drum 211 with laser light based on an image processing electric signal from an image processing unit (not shown) of the image reading device 203, and the electrostatic latent image corresponding to the image of the document on the photosensitive drum 211. Form. The developing device 214 develops the electrostatic latent image on the rotating photosensitive drum 211 into a toner image.

  On the other hand, the pickup roller 109 sends out the sheets P stored in the sheet cassette 101 one by one from the sheet cassette 101. The conveyance roller pairs 121, 122, and 123 send the sheet fed from the sheet cassette 101 to the registration roller pair 125 that stops rotating by guiding the sheet conveyance path 124. The registration roller pair 125 receives the leading edge of the sheet and feeds the sheet between the photosensitive drum 211 and the transfer charger 216 in accordance with the toner image formed on the photosensitive drum 211. The transfer charger 216 transfers the toner image on the photosensitive drum 211 to the sheet. The separation charger 217 separates the sheet from the photosensitive drum 211. The cleaner 218 cleans the photosensitive drum 211 by removing the residual toner remaining on the photosensitive drum 211.

  The conveyance belt 219 sends the sheet on which the toner image is transferred to the fixing device 220. The fixing device 220 heats and presses the sheet to fix the toner image on the sheet. When an image is formed only on one side of the sheet, the discharge roller pair 221 discharges the sheet to the discharge tray 222.

  When forming an image on the other side of the sheet, the flapper 223 guides the sheet to the sheet conveyance path 224. The pair of conveyance rollers 225 and 226 pulls the sheet and sends it to the conveyance path 227. The conveyance roller pair 226 reversely rotates when the downstream end of the sheet passes through the flapper 228 and reversely feeds the sheet. At this time, the flapper 228 is inclined to the right in FIG. 1 to guide the sheet to the reverse conveyance path 229. In this way, the sheet is turned upside down while being switched back through the sheet conveyance path 224, the pull-in conveyance path 227, and the reverse conveyance path 229.

  The conveyance roller pairs 230, 231 and 232 in the reverse conveyance path 229 send the sheet to the registration roller pair 125. Thereafter, the image forming apparatus 201 forms an image on the other side of the sheet and discharges it to the discharge tray 222 by the same operation as when an image is formed on one side.

(Sheet feeding device)
FIG. 2 is a plan view of the sheet feeding apparatus. FIG. 3 is a cross-sectional view taken along line AA in FIG.

  The sheet supply apparatus 100 according to the present embodiment is capable of contacting and separating the sheet cassette 101 as a sheet stacking unit on which sheets are stacked and can be taken in and out of the apparatus main body 202, and the uppermost sheet among the sheets. A pickup roller 109 serving as a sheet supply unit that contacts the sheet and feeds the uppermost sheet in a direction intersecting with the loading / unloading direction of the sheet cassette 101, and a pickup roller after the sheet cassette 101 is inserted into the apparatus main body 202 A control unit 240 (see FIG. 1) as a control unit that separates the pickup roller 109 from the uppermost sheet at least once before the sheet starts to be fed. Side regulating plate 102 as an alignment member for aligning the front end of the sheet A, the end of the sheet out side of the matching surface 102a of the alignment portion for aligning the sheet side regulating plate 102 is provided with projections 110 as the slip prevention means for preventing the slipping in the thickness direction of the sheet.

  The sheet cassette 101 includes side regulating plates 102 and 103 that perform sheet width alignment to prevent oblique feeding of the stacked sheets P, and a trailing edge regulating plate that receives the trailing edge Pb of the sheet P and regulates reverse feeding of the sheet P. 104, a leading edge regulating plate 105 that receives the leading edge Pf of the sheet P and regulates the movement of the sheet P downstream in the sheet conveying direction, a bottom plate 106 on which the sheets are stacked, and a bottom plate centering on the rotation center 107. A lift-up mechanism 108 that lifts up 106, a pair of slide rails 113, 113, and the like are included.

  The sheet cassette 101 can be pushed into and pulled out from the apparatus main body 101 in the direction of the arrow shown in FIG. 2 by guiding a slide rail 113 in a groove (not shown) provided in the apparatus main body 202. The sheet cassette 101 is normally pushed into the apparatus main body 101, and is pulled out by the user when the sheet is replenished. After the sheet is replenished, the sheet cassette 101 is pushed into the original state.

  The bottom plate 106 on which the sheets are stacked is raised to a predetermined position by the lift-up mechanism 108, and the pickup roller 109 comes into contact with the uppermost sheet among the sheets stacked on the raised bottom plate 106. Yes.

  FIGS. 4 to 6 are diagrams for explaining the operation when the sheet cassette 101 full of sheets is inserted into the apparatus main body 202.

  The bottom plate 106 (see FIG. 3) on which sheets are stacked is raised to a predetermined position by the lift-up mechanism 108 while the sheet cassette 101 is being inserted into the apparatus main body 202. On the other hand, as shown in FIG. 4, the pickup roller 109 attempts to descend to the lowering standby position as the sheet cassette 101 is inserted, but contacts the uppermost sheet Pa during the lowering.

  The sheet cassette 101 is further inserted into the apparatus main body 202 while the pickup roller 109 is in contact with the uppermost sheet Pa. Then, as shown in FIG. 5, the uppermost sheet Pa is prevented from moving by the pickup roller 109, slides against the lower sheet P2, and a side edge Pc is abutted against the side regulating plate 102 to bend. . If the pip-up roller 109 starts to supply the sheet in this state, the uppermost sheet may be conveyed with its position shifted to cause jamming. Note that the side edge of the sheet indicated by the reference symbol Pc is the front edge in the direction in which the sheet cassette 101 is inserted and removed.

  Therefore, the control unit 240 (see FIG. 1) temporarily separates the pickup roller 109 from the uppermost sheet Pa before returning the sheet by the pickup roller 109. The sheet moves with the side regulating plate 102 as a base point due to the repulsive force of the portion that is bent between the pickup roller 109 and the side regulating plate 102 (curled portion) to eliminate the deviation and lower The end of the sheet P2 is aligned. The time for the uppermost sheet Pa to move is instantaneous, and it is sufficient that the pickup roller 109 is separated from the uppermost sheet Pa for about 1 second.

  As described above, the sheet supply apparatus 100 according to the present embodiment can be used immediately after the sheet cassette 101 is completely mounted on the apparatus main body 202, immediately after the cassette is mounted, immediately after the copier is turned on, or immediately before the pickup operation is started. At any time, once the pickup roller 109 is separated from the uppermost sheet, the sheet can be supplied and conveyed in a stable state with almost no displacement.

  Note that the retracting operation of the pickup roller 109 is not necessarily performed. That is, whether the uppermost sheet is in contact with the pickup roller 109 when the sheet cassette 101 is mounted is detected by the operation amount of the lift-up mechanism 108, the height detection sensor of the sheet surface, and the like. Only when the sheet is misaligned, the pickup roller 109 may be temporarily retracted from the uppermost sheet.

  By the way, the above-mentioned bending does not necessarily occur in the sheet. As described with reference to FIG. 9, the sheet may enter the gap between the already stacked sheets and the side regulating plate, or the sheet may get over the side regulating plate, so that the bending may not be formed.

  Therefore, as shown in FIG. 7, the sheet supply apparatus 100 according to the present embodiment is provided with a plurality of protrusions 110 on the alignment surface 102 a of the side regulating plate 102 against which the uppermost sheet Pa is pressed, so that the side edge of the sheet Pc is prevented from escaping. The interval in the vertical direction (sheet thickness direction) of the plurality of protrusions 110 is set to a gap in which the sheet can enter. The protrusion 110 is provided at a position facing the pickup roller 109 so that the side edge Pc of the sheet can be reliably received. That is, the plurality of protrusions 110 are provided at the position of the side regulating plate 102 on the axis of the pickup roller 109. Further, the protrusion 110 is provided on the upper side of the side regulating plate 102 so that the sheet is difficult to get over the side regulating plate 102.

  Therefore, the sheet feeding apparatus 100 can bend the sheet regardless of the strength of the waist of the sheet, with the plurality of protrusions 110 as the base point of the side end Pc of the uppermost sheet Pa pressed against it. Deviation in the width direction (left-right direction in FIG. 7) of the uppermost sheet can be reduced.

  The protrusion 110 protrudes from the alignment surface 102a of the side regulating plate 102. For this reason, the position of the uppermost sheet is shifted in the width direction by the distance L2 from the lower sheet with which the protrusion 110 is in contact.

Specific numerical values of the deviation amount are as follows. That is, in a high-temperature and high-humidity environment where the repulsive force of the bent sheet weakens, for example, a thin sheet such as an A4 size and a basis weight of 52.8 g / m ² is placed between the pickup roller 109 and the side regulating plate 102. A gap of about 15 mm (= L2) is generated between them. This deviation amount is an amount that can sufficiently correct the deviation in the width direction in an apparatus having a lateral registration adjusting mechanism (not shown). The lateral registration adjusting mechanism is, for example, a mechanism that detects a deviation in the width direction by a sensor and slides the pickup roller 109 in a direction intersecting the sheet conveyance direction (sheet width direction) to match the sheet to the conveyance reference position. is there. Further, 15 mm is an amount of displacement in the width direction that does not hinder image formation even if a lateral registration adjusting mechanism is not provided.

  As described above, the sheet supply apparatus 100 according to the present embodiment does not cause the side edge Pc of the sheet to enter the gap G between the side regulating plate 102 and the already stacked sheets P by the plurality of protrusion shapes 110. Alternatively, a loop is formed on the uppermost sheet Pa without overcoming the side regulating plate 102, and the pickup roller 109 is once separated from the uppermost sheet surface, thereby shifting the uppermost sheet in the width direction. Can be reduced.

  In addition, since the sheet supply apparatus 100 has a plurality of protrusions 110 provided at the position of the side regulating plate 102 on the axis of the pickup roller 109, the sheet feeding device 100 is provided at the side edge Pc of the sheet more than when provided at another position of the side regulating plate 102. It has a structure in which it is possible to prevent the sinking and to easily form a loop that eliminates the deviation in the width direction of the uppermost sheet Pa.

  In addition, the effect is the same even if the protrusion 110 is either the same member as the side regulating plate 102 or another member attached to the side regulating plate 102. Further, the plurality of protrusions may be rigid or elastic.

  Further, the portion provided with the protrusion 110 may be a rough surface as a non-slip surface. Or you may provide the anti-slip | skid member 250 with a high friction coefficient like rubber | gum as shown in FIG. That is, the portion provided with the protrusion 110 may be a non-slip surface 250a as anti-slip means. The anti-slip surface is a surface having a higher coefficient of friction than the matching surface 102a of the side regulating plate 102. The value of the friction coefficient is preferably a value that does not interfere with the feeding of the sheet from the sheet cassette.

  As described above, when the anti-slip surface 250a is used, the side edge Pc of the sheet can be prevented from slipping, and the sheet can be bent with the side edge Pc of the sheet as the base end. Can be resolved.

  Further, when the anti-slip surface 250a is flush with the alignment surface 102a of the side regulating plate 102, the width of the sheet bundle is reliably aligned with the pair of side regulating plates 102 and 103 (see FIG. 2). The sheet can be fed downstream without the need to operate the lateral registration adjusting mechanism.

  Further, the anti-slip surface 250a may be extended to near the bottom plate 106 (see FIG. 3). In this case, the sheet can be bent regardless of the number of sheets stacked.

  As described above, in the sheet feeding apparatus of the present invention, the pickup roller 109 and the uppermost sheet Pa come into contact with each other so that the sheet slides in the width direction (direction intersecting the sheet conveying direction). However, since the sheet is bent with the protrusion 110 or the anti-slip surface 250a receiving the side edge Pc of the sheet by the protrusion 110 or the anti-slip surface 250a provided on the side regulating plate 102, the sheet is bent in the width direction. Thus, the sheet feeding operation can be performed in a stable state.

  In addition, since the sheet supply apparatus of the present invention is configured to supply the sheet so as to reduce the deviation in the width direction of the sheet and prevent the sheet from being jammed, the copying machine 201 provided with this sheet supply apparatus is The image forming operation rate can be improved.

1 is a cross-sectional view taken along a sheet conveying direction of a copying machine as an image forming apparatus according to an embodiment of the present invention. It is a top view of the sheet supply apparatus in the embodiment of the present invention. FIG. 3 is a cross-sectional view taken along line AA in FIG. FIG. 10 is a diagram for explaining an operation when a sheet cassette full of sheets is inserted into the apparatus main body. FIG. 5 is a state diagram when the sheet cassette is inserted into the apparatus main body following the operation shown in FIG. 4 and the sheet is bent by the pickup roller. FIG. 6 is a diagram illustrating a state in which the pickup roller illustrated in FIG. 5 is once separated from the sheet and the bending of the sheet is eliminated. FIG. 4 is a schematic cross-sectional view taken in the direction in which the sheet cassette of the sheet supply apparatus is put in and out, and is a view showing a protrusion portion. In FIG. 7, it is a figure at the time of providing the anti-slip | skid member instead of protrusion. In the conventional sheet supply apparatus, it is sectional drawing along the taking in / out direction of a sheet cassette.

Explanation of symbols

P Sheet Pc The front end portion 100 of the sheet in the direction in which the sheet cassette is loaded and unloaded 100 Sheet feeding device 101 Sheet cassette (sheet stacking means)
102 Side regulating plate (alignment member)
102a Alignment surface (alignment part)
103 Side regulating plate 106 Bottom plate 108 Lift-up mechanism 109 Pickup roller (sheet supply means)
110 Protrusion (Anti-slip means)
201 Copying machine (image forming apparatus)
202 Copier main body 203 Image reading device 204 Automatic document feeder 211 Photosensitive drum (image forming means)
240 Control unit (control means)
250 Non-slip member (slip prevention means)
250a Non-slip surface

Claims (5)

A sheet stacking means in which sheets are stacked and can be taken in and out of the apparatus body;
Sheet supply means capable of coming into contact with and separating from the uppermost sheet of the sheets stacked on the sheet stacking means and sending the uppermost sheet in a direction intersecting with the loading / unloading direction of the sheet stacking means; Have
In the sheet supply apparatus in which the sheet supply unit is separated from the uppermost sheet after the sheet stacking unit is inserted into the apparatus main body until the sheet supply unit starts supplying the sheet.
The sheet stacking means has an alignment member for aligning the front end of the sheet in the loading / unloading direction of the sheet stacking means;
The sheet feeding apparatus according to claim 1, wherein an anti-slip means for preventing the front end portion of the sheet from sliding in the thickness direction of the sheet is provided in the aligning portion for aligning the sheets of the aligning member.   The sheet feeding apparatus according to claim 1, wherein the anti-slip unit is provided at a position facing the sheet feeding unit when contacting the sheet.   The sheet feeding device according to claim 1, wherein the anti-slip means is a plurality of protrusions that protrude toward the front end portion of the sheet and that are provided in the thickness direction of the sheet.   The sheet feeding device according to claim 1 or 2, wherein the anti-slip means is a non-slip surface having a larger coefficient of friction than the other part of the aligning portion. A sheet feeding device according to any one of claims 1 to 4,
Image forming means for forming an image on the sheet supplied from the sheet supply device;
An image forming apparatus.

Images