JP2018002470A - Sheet feeding device and image formation apparatus - Google Patents

Abstract

Provided is a paper feeding device capable of stably feeding out paper even when a small-diameter feeding roller is used. A sheet feeding device (12) presses against and rotates a sheet (S) to feed the sheet (S), and presses against the feeding roller (21) to form a separation nip (N). A separating pad 34 for separating the fed sheets S one by one in the separation nip N. Further, the sheet roller 21 is erected along the feeding direction on both outer sides of the feeding roller 21 in the sheet width direction orthogonal to the feeding direction of the sheet S, and the pressure contact between the feeding roller 21 and the sheet S is achieved. Between the position P and the separation nip N, the guide portion 35 protrudes in a direction closer to the feeding roller 21 than the extension line L of the separation nip N and guides the leading edge of the sheet S to the separation nip N. Have [Selection] Figure 6

Description

    The present invention relates to a sheet feeding device that feeds out a sheet and an image forming apparatus including the sheet feeding device.

  2. Description of the Related Art Image forming apparatuses such as copying machines and printers are provided with a paper feeding device that feeds sheets stacked on a paper feeding cassette or a manual feed tray to an image forming unit. In order to prevent double feeding of paper, the paper feeding device may be provided with a separating pad that is in pressure contact with a feeding roller that feeds out the paper, as described in Patent Document 1.

  When multiple sheets are sent out, they are transported one sheet at a time by the resistance of the pad when the fed sheet passes through the separation nip formed between the feed roller and the pad. Is done.

JP 2006-306597 A

  By the way, when the diameter of the feeding roller is reduced in accordance with the space saving of the image forming apparatus, the feeding of the sheet from the sheet feeding cassette and the sheet at the separation nip as in the sheet feeding apparatus described in Patent Document 1 are performed. If the rolling is performed with one feeding roller, the following problems occur.

  That is, as shown in FIG. 8, the paper feed path L1 at the contact position between the feed roller and the paper (the path toward the tangential direction of the feed roller at the contact position) and the transport of the paper at the separation nip. The angle β with the small-diameter feeding roller R2 is smaller than the angle α with the large-diameter feeding roller R1. Then, the sheet fed by the feeding roller enters so as to collide with the separation pad, and comes into contact with the separation pad on the near side of the separation nip without being directly fed to the separation nip.

  In other words, the conveyance angle of the fed paper is greatly changed in the small-diameter feeding roller R2. In the case of paper with weak stiffness, the posture can be changed in accordance with the conveyance angle, so that the paper is fed to the separation nip following the whirling pad. However, in the case of thick paper that is stiff, it is difficult to change the posture in accordance with the conveyance angle, so that contact with the separation pad may cause resistance from the separation pad and cause conveyance failure.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a paper feeding device capable of stably feeding paper even when a small-diameter feeding roller is used, and an image forming apparatus including the paper feeding device. And

  In order to solve the above-described problems, a paper feeding device according to the present invention forms a separation nip by being in pressure contact with a paper feeding roller and rotating the paper by feeding the paper, and by pressing the paper feeding roller. A paper feeding device that separates the fed paper one by one in the separation nip, on both outer sides of the feeding roller in the paper width direction perpendicular to the paper feeding direction, It is erected along the feeding direction and protrudes in a direction closer to the feeding roller than an extension line of the separation nip between a pressure contact position between the feeding roller and the sheet and the separation nip. And a guide portion for guiding the leading edge of the sheet to the separation nip.

  By adopting such a configuration, the thick paper comes into contact with the guide nip before the separation nip and is guided to the separation nip, and the thin paper is bent downward between the guide parts before the separation nip, The deflected center is guided along the padding to the separation nip. Therefore, even if the diameter of the feeding roller is reduced, both the thick paper and the thin paper can be stably guided to the separation nip, so that the paper can be prevented from being double fed.

  In the paper feeding device according to the present invention, the guide portion may be provided outside 40 mm to 60 mm with respect to the center in the width direction.

  By adopting such a configuration, it is possible to appropriately deflect the thin paper between the guide portions, and it is possible to make the leading end of a narrow thick paper such as a postcard or an envelope come into contact with the guide portion.

  An image forming apparatus according to the present invention includes any of the above-described sheet feeding devices.

  According to the present invention, the thick paper abuts on the guide portion before the separation nip and is guided to the separation nip, and the thin paper is bent at the center portion between the guide portions before the separation nip, and the bent center portion. Since the portion is guided along the separation pad to the separation nip, even if the diameter of the feeding roller is reduced, both the thick paper and the thin paper can be stably guided to the separation nip, so that it is possible to prevent double feeding of the paper.

1 is a side view schematically showing an internal structure of a printer according to an embodiment of the present invention. It is a perspective view which shows the paper feed roller of the manual paper feed part which concerns on one Embodiment of this invention. It is a perspective view showing a paper feed unit of a manual paper feed unit according to an embodiment of the present invention. It is a perspective view which shows the upright part of the manual sheet feed part which concerns on one Embodiment of this invention. 4 is a side cross-sectional view showing the periphery of a feed roller in a manual paper feed unit according to an embodiment of the present invention. FIG. 4 is a side sectional view showing guide ribs in the manual sheet feeder according to the embodiment of the present invention. In the printer which concerns on one Embodiment of this invention, it is a figure which shows the thin paper bent between a pair of guide ribs. It is a figure explaining the change of the conveyance angle by the diameter of a feed roller.

  Hereinafter, an image forming apparatus and a sheet feeding device according to an embodiment of the present disclosure will be described with reference to the drawings.

  First, an overall configuration of a printer 1 as an image forming apparatus will be described with reference to FIG. FIG. 1 is a schematic diagram showing an outline of a printer according to an embodiment of the present invention. In the following description, the front side of the sheet of FIG. 1 is the front side (front side) of the printer 1, and the left and right directions are based on the direction when the printer 1 is viewed from the front.

  The apparatus main body 2 of the printer 1 includes a paper feeding unit 3 that feeds the paper S, an image forming unit 4 that forms a toner image on the fed paper S, a fixing device 5 that fixes the toner image to the paper S, and a paper A paper discharge device 6 that discharges S and a paper discharge tray 7 that receives the discharged paper S are provided. Further, the apparatus main body 2 is formed with a conveyance path 9 through which the sheet S is conveyed from the paper supply unit 3 through the image forming unit 4 and the fixing device 5 toward the discharge device 6.

  The sheet feeding unit 3 includes a cassette sheet feeding unit 11 and a manual sheet feeding unit 12 as sheet feeding devices. The cassette paper feeding unit 11 is provided in the lower part of the apparatus main body 2, and the manual paper feeding unit 12 is provided on the right side surface of the apparatus main body 2. The cassette paper feeding unit 11 includes a paper feeding cassette 15 that is detachably attached to the apparatus main body 2 and on which the paper S is stacked, and a paper feeding unit 16 that feeds the paper S from the paper feeding cassette 15. It has been. The manual sheet feeder 12 will be described later.

  The paper S fed from the paper supply unit 3 is transported along the transport path 9, and after the toner image is formed in the image forming unit 4, the toner image is fixed on the paper S by the fixing device 5. The sheet S on which the toner image is fixed is conveyed to the discharge device 6 and discharged to the discharge tray 7.

  Next, the manual sheet feeder 12 will be described with reference to FIGS. 1 and 2 to 5. 2 is a perspective view showing the feeding roller, FIG. 3 is a perspective view showing the paper feeding unit, FIG. 4 is a perspective view showing an upright portion of the paper feeding unit, and FIG. 5 is a side sectional view showing the periphery of the feeding roller, FIG. 6 is a side sectional view showing the guide rib.

  The manual paper feed unit 12 is provided on the right side surface of the apparatus main body 2 as shown in FIG. Formed on the right side surface of the apparatus main body 2 are a paper receiving port 2a opened along a width direction orthogonal to the paper feeding direction and a shallow concave portion 2b. The recess 2b is formed above the sheet receiving port 2a.

  The manual paper feed unit 12 includes a feeding roller 21 provided at the upper part inside the paper receiving port 2a and a paper feeding unit 22 provided at the lower part of the paper receiving port 2a.

  As shown in FIG. 2, the feeding roller 21 includes a pair of roller main body portions 21 a and a rotation shaft 21 b provided at the axis of the pair of roller main body portions 21 a. A pair of roller main-body parts 21a is provided in the longitudinal direction center part of the rotating shaft 21b at predetermined intervals.

  The feeding roller 21 is rotatably supported on the inner upper portion of the paper receiving port 2a. A rotational force is transmitted from a driving source (not shown) such as a motor to the rear end portion of the rotating shaft 21b. The feeding roller 21 is rotated in the clockwise direction in FIG. 2 by the driving source.

  As shown in FIG. 3, the paper feed unit 22 has a support member 31 fixed to a lower portion of the paper receiving port 2 a, a manual feed tray 32 that is rotatably supported by the support member 31, and a manual feed tray 32. A pair of lift plates 33 provided on the downstream side in the feed direction, two scissor pads 34 provided on the downstream side in the feed direction with respect to the lift plate 33, and a pair of guide portions provided on both sides in the width direction of the scoop pad 34 And a guide rib 35 (see FIG. 4).

  The support member 31 has a base portion 31a along the lower edge of the sheet receiving port 2a, and an upright portion 31b erected from the downstream end of the base portion 31a in the feeding direction.

  A manual feed tray 32 is supported on the base portion 31a so as to be rotatable in the vertical direction around the lower end portion. The manual feed tray 32 is a rectangular plate-shaped member having a stacking surface 32a on which sheets are stacked. The manual feed tray 32 has an accommodation position rotated upward until it is accommodated in the recess 2b (see FIG. 1), a manual feed position rotated downward until it is supported in a substantially horizontal posture by a stopper (not shown), Rotate up and down.

  A lift plate 33 is supported on the base portion 31a downstream of the manual feed tray 32 in the feed direction so as to be pivotable in the vertical direction around the upstream end of the feed direction. The lift plate 33 is a plate-like member that is long in the width direction and supports the leading end of the paper loaded on the manual feed tray 32. A plurality of guide pieces 33 a protruding downstream are formed at the downstream edge of the lift plate 33 in the feeding direction. Further, two friction pads 36 are attached at a predetermined interval at the center in the width direction of the downstream edge of the lift plate 33 in the feeding direction.

  Further, the lift plate 33 is movable in the vertical direction at the downstream end in the feeding direction by a drive mechanism (not shown). When the lift plate 33 is rotated upward by the drive mechanism until the lift plate 33 becomes substantially horizontal, the leading end of the sheet is lifted and pressed against the roller body 21a of the feeding roller 21 from below as shown in FIG. The Further, when it is rotated downward, it is inclined obliquely downward and is separated downward from the feeding roller 21.

  As shown in FIG. 4, a guide surface 38 is formed on the upper portion of the upright portion 31b of the support member 31 so as to be inclined obliquely upward and guide the sheet to the conveyance path. The guide surface 38 is formed so as to continue to the downstream side in the feeding direction from the upper surface of the lift plate 33 rotated upward in a substantially horizontal state. At the center of the guide surface 38 in the width direction, a padding recess 39 is formed.

  Furthermore, a plurality of guide grooves 41 are formed in the upright portion 31 b of the support member 31 to guide the guide pieces 33 a when the lift plate 33 is rotated. The guide groove 41 is formed in an arc shape in a side view so as to follow the turning locus of the tip of the lift plate 33.

  The two spreading pads 34 are each formed of a material (for example, rubber) having a large friction coefficient. As shown in FIG. 4, the two spreading pads 34 are supported by the holder 43 in a state of being aligned in the width direction. The holder 43 is supported by the padding recess 39 so that the two padding pads 34 are inclined upward in the same manner as the guide surface 38. Further, the holder 43 is detachable from the padding recess 39, and can be easily replaced when the pad 34 is worn.

  When the holder 43 on which the two padding pads 34 are supported is attached to the padding recess 39, the two padding pads 34 are respectively connected to a pair of two feeding rollers 21 as shown in FIG. Each roller body 21 a is pressed to form a separation nip N between the roller body 21 a and the pad 34.

  As shown in FIG. 4, the pair of guide ribs 35 are on both sides of the padding recess 39 and outward from the center C in the width direction of the support member 31 by a predetermined distance D and near the upper end from the lower end of the upright portion 31 b. It is erected along the feeding direction. The distance D is, for example, 40 mm to 60 mm. Further, the cross-section of the upper end portion of the guide rib 35 is curved in a convex arc shape.

  The guide rib 35 will be described in detail with reference to FIG. FIG. 6 is a side sectional view showing the guide rib.

  The guide ribs 35 erected on the guide surface 38 are, in order from the upstream side in the feeding direction, an upstream inclined portion 35a that is gradually inclined upward toward the downstream side with respect to the guide surface 38, and an upstream inclined portion 35a. It has a downstream inclined portion 35c that is gently inclined downward with respect to the guide surface 38 from the top portion 35b toward the downstream side, and a parallel portion 35d that is parallel to the guide surface 38.

  The upstream inclined portion 35 a is inclined toward the separation nip N between the pressure contact position P between the lift plate 33 and the feeding roller 21 and the separation nip N. The top portion 35 b protrudes most toward the feeding roller 21 beyond the extension line L of the separation nip N. However, when viewed from the axial direction of the feeding roller 21, the roller body 21a and the guide rib 35 do not overlap. The downstream inclined portion 35 c is inclined in the direction of retreating from the separation nip N. The parallel portion 35d is separated from the feeding roller 21 rather than the separation nip N and extends substantially parallel to the separation nip N. Further, a tangent line T passing through the pressure contact position P between the sheet S placed on the lift plate 33 rotated upward and the feeding roller 21 is slightly upstream from the top portion 35b of the guide rib 35 in the feeding direction. It intersects with the inclined portion 35a.

  When the sheet S is fed from the manual sheet feeder 12 having the above-described configuration, the uppermost sheet S among the sheets stacked on the manual tray 32 by the rotation of the lift plate 33 is fed to the feeding roller 21. Press contact. When the feeding roller 21 rotates, the uppermost sheet S is fed out by friction with the feeding roller 21. The fed sheet S comes into contact with the pair of guide ribs 35 before the separation nip N, is guided along the pair of guide ribs 35, and is conveyed to the nip N.

  When the sheet S that has been sent out is a single sheet, the sheet S is conveyed downstream by friction with the feeding roller 21. When a plurality of sheets S are sent out, the frictional force between the sheet S and the feeding roller 21 is larger than the frictional force between the sheet S and the separation pad 34, so that only the uppermost sheet S is the feeding roller. Sent out.

  When the paper S is a strong thick paper, the paper S sent out by the feed roller 21 is sent along the tangent line T, and the front end of the pair of guide ribs 35 is near the front of the pair of guide ribs 35 before the separation nip N. Touch. Then, since the guide is guided to the separation nip N along the pair of guide ribs 35, the tip does not collide with the spreading pad 34. In the case of thick paper, a plurality of sheets are rarely fed by the feeding roller 21 due to the weight of the paper itself, and it is easy to roll even in the separation nip N. Therefore, the thick paper is stably guided to the separation nip N by the pair of guide ribs 35.

  On the other hand, when the paper S is thin paper that is weak, a plurality of sheets are often fed out by the feeding roller 21. For this reason, when a plurality of sheets S are sent out to the separation nip N along the pair of guide ribs 35, it becomes difficult to spread the sheets S at the separation nip N. However, in the case of the weak paper S, the leading edge of the paper fed by the feeding roller 21 abuts against the pair of guide ribs 35 before the separation nip N. However, since the stiffness is weak, it is shown in FIG. As described above, the central portion M of the sheet S bends downward between the pair of guide ribs 35. Then, the bent tip of the central portion M hits the separation pad 34 before the separation nip N between the pair of guide ribs 35, and is sent to the separation nip N along the separation pad 34. Then, the uppermost sheet is separated at the separation nip N.

  Here, since the pair of guide ribs 35 are formed outside by a predetermined distance D40 mm to 60 mm from the center C in the width direction of the support member 31, the weak paper S is the center of the paper S between the pair of guide ribs 35. The portion can be appropriately bent so as to abut against the padding pad 34. On the other hand, the paper S having a narrow width and strong stiffness like an envelope can be brought into contact with the pair of guide ribs 35 before the separation nip N.

  As described above, in the manual sheet feeding portion 12 of the present invention, the thick paper comes into contact with the pair of guide ribs 35 before the separation nip N and is guided to the separation nip N along the pair of guide ribs 35. On the other hand, the thin paper is deflected downward between the pair of guide ribs 35 before the separation nip N, and the bent central portion is guided to the separation nip N along the scooping pad 34. Therefore, even if the diameter of the feeding roller 21 is reduced, both thick paper and thin paper can be stably guided to the separation nip N. In addition, it is possible to reliably prevent double feeding of sheets in the separation nip N.

  Further, since the pair of guide ribs 35 are formed 40 mm to 60 mm outside from the center in the width direction, the center portion of the thin paper S can be appropriately bent, while the width of the envelope or the like is narrow and firm. The sheet S can be brought into contact with the pair of guide ribs 35.

  In the present embodiment, the case where the present invention is applied to the manual sheet feeding unit 12 has been described. However, the present invention can also be applied to the cassette sheet feeding unit 11. Alternatively, the present invention can also be applied to the paper feed unit of the document feeder.

  The above description of the embodiment of the present invention describes a preferred embodiment of the paper feeding device and the image forming apparatus according to the present invention, and therefore may have various technically preferable limitations. However, the technical scope of the present invention is not limited to these embodiments unless specifically described to limit the present invention. That is, the above-described components in the embodiment of the present invention can be appropriately replaced with existing components and the like, and various variations including combinations with other existing components are possible. The description of the embodiment of the present invention described above does not limit the contents of the invention described in the claims.

1 Printer (image forming device)
12 Manual paper feeder (paper feeder)
21 Feed roller 34 Whisper pad 35 Guide rib (guide part)

Claims (3)

A feeding roller that feeds the paper by rotating in pressure contact with the paper;
A sheet feeding device comprising: a separation pad formed in pressure contact with the feeding roller; and a separating pad that separates the fed sheets one by one in the separation nip,
A pressure contact position between the feeding roller and the sheet, the separation nip, and both sides of the feeding roller in a sheet width direction orthogonal to the sheet feeding direction are provided along the feeding direction. In the sheet feeding apparatus, the sheet feeding device further includes a guide portion that protrudes in a direction closer to the feeding roller than the extension line of the separation nip and guides the leading edge of the sheet to the separation nip.   The sheet feeding device according to claim 1, wherein the guide portion is provided outside 40 mm to 60 mm with respect to the center in the width direction.   An image forming apparatus comprising the sheet feeding device according to claim 1.

Images