JP2012051720A - Sheet feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet feeder capable of stably feeding a number of sheets and, when a user sets sheet bundles, capable of eliminating the need for the operation of handling the sheet bundles with hand to assume a state facilitating feeding.SOLUTION: The sheet feeder has a stopper against which the sheet bundles are struck, wherein, before a separation feeding operation is started, the stopper is fixed at a protrusion position to cause the sheet bundles to stand by on the upper stream side than a separation feeding part and the stopper is moved to a retreating position when starting the separation feeding to allow the entry of the sheet into a separation nip part between a feeding roller and a separation roller.

Description

  The present invention relates to a sheet feeding apparatus that can be incorporated in an image forming apparatus such as a copying machine or a printer, or an image reading apparatus such as a scanner, or that can be used in combination therewith.

  In the conventional sheet feeding apparatus, when a sheet is fed by the feeding mechanism of the apparatus after the user sets the sheet in the sheet feeding port, the leading end of the sheet bundle is automatically skewed and fed. There has been proposed a sheet winding mechanism that includes a front winding mechanism in which the leading end of a sheet bundle that enters the mechanism is inclined and the sheets that are fed earlier are projected more. For example, Patent Document 1 discloses a mechanism for winding a sheet bundle with a winding member close to a roller as shown in FIG.

According to such a sheet rolling mechanism, even if sheets are not loaded in the sheet feeding tray, the sheet feeding mechanism rolls the leading end of the sheet bundle when feeding sheets, and a large number of sheets are separated. The separation nip part of the feeding part is prevented from entering.

Further, Patent Document 2 proposes a sheet feeding device having a mechanism for rolling the leading end portion of a sheet bundle to be fed by a slope-shaped portion provided in the vicinity of the sheet feeding port as shown in FIG.

According to this sheet rolling mechanism, when a sheet bundle is set in the sheet feeding tray, the leading edge of the sheet bundle hits against the inclined surface portion of the sheet feeding port so that the leading edge of the sheet is inclined, thus preventing double feeding of sheets. it can.

JP-A-12-001233 Japanese Patent Laid-Open No. 06-040584

However, in the conventional sheet winding mechanism described in Patent Documents 1 and 2 and the like, if a user pushes a large number of sheet bundles into a sheet feeding tray, the separation nip between the feeding roller and the separation roller is forced. Since a plurality of sheets enter the part and cause double feeding, sufficient care must be taken when setting the sheet bundle.

Further, in the conventional sheet winding mechanism described in Patent Documents 1 and 2 and the like, the position of the front winding mechanism is changed when the user sets a sheet bundle and after the sheet feeding device starts feeding. This is not preferable from the viewpoint of protecting the sheet because the front winding mechanism presses the sheet being fed.

The present invention provides a sheet feeding apparatus that can stably feed without needing a sheet winding operation to prevent double feeding of sheets and without causing damage to the surface of the sheet during feeding. The purpose is to do.

  The sheet feeding device of the present invention was invented to solve the above-described problem, and has a separation nip portion for feeding sheets one by one from a sheet bundle placed on the sheet stacking surface. In the sheet feeding apparatus including a feeding unit and a sheet abutting surface that abuts the leading end of the sheet and capable of waiting the sheet in front of the separation feeding unit, the stopper is The sheet abutting surface allows a first position in which all the sheets of the sheet bundle stand by in front of the separation nip portion, and allows a part of the sheets of the sheet bundle to enter the separation nip portion, and the rest The sheet is allowed to move to a second position where the sheet is made to wait by the sheet abutting surface, and the sheet abutting surface is arranged to be adjacent to at least a part of the placed sheet. Characterized in that it has a shape to rise to positional displacement of the tip between.

  According to the present invention, it is possible to omit the operation of scratching the front end of the sheet bundle before setting the sheet bundle, and it is possible to obtain a stable feeding performance.

1 is a schematic cross-sectional view of a sheet feeding apparatus according to an embodiment. 1 is a schematic cross-sectional view of a sheet feeding apparatus according to an embodiment. 1 is a schematic cross-sectional view of a sheet feeding apparatus according to an embodiment. FIG. 5 is a diagram for explaining a main part of the sheet feeding apparatus according to the embodiment. 1 is a schematic cross-sectional view of a sheet feeding apparatus according to an embodiment. It is the schematic of the roller cover which concerns on embodiment. It is a figure for demonstrating the conventional sheet rolling mechanism. It is a figure for demonstrating the conventional sheet rolling mechanism.

  Embodiments of the present invention exemplified below will be described with reference to the drawings. In each embodiment, an image reading apparatus will be described as an example. However, the present invention is applicable to a facsimile machine, a scanner, a copying machine, a printer, and a multifunction machine having some of these functions. Further, the present invention can be applied to an apparatus having a sheet feeding function used in combination with these apparatuses.

FIG. 1 is a schematic sectional view of an image reading apparatus provided with a sheet feeding apparatus as a first embodiment of the present invention. In FIG. 1, an image reading apparatus 1 is a document scanner, and is an apparatus that reads an image formed on a sheet original by a contact image sensor as image reading means.

The configuration of the image reading apparatus 1 will be described. Sheets that are originals to be read are stacked on the sheet supply tray 2. The feeding roller 3 is a roller positioned below the sheet to be fed in order to feed the sheet placed on the stacking surface of the sheet supply tray 2 into the apparatus main body. The separation roller 4 is an example of a separation member disposed on the upper side with respect to a sheet to be fed. When a plurality of sheets are fed into the apparatus main body by the feeding roller 3, the sheets are separated one by one. Laura. The separation feeding mechanism having the feeding roller 3 and the separation roller 4 is an example of a separation feeding unit.

The roller cover 5 is rotatable about the rotation shaft 6 as a fulcrum, and is urged to rotate obliquely upward by a tension spring 7 hung near the free end far from the rotation shaft 6. In a normal state, as shown in FIG. 2, it comes into contact with the abutting member B and stops at the retracted position. In order to rotate the roller cover 5 against the urging force of the tension spring 7, the cam 8 is driven to rotate. The cam 8 is connected to a drive unit 14 including a drive source such as a motor. When the cam 8 is rotated by the drive unit 14, the cam 8 rotates while contacting the roller cover 5, and the roller is moved toward the feed roller 3. The cover 5 is pushed down, and the roller cover 5 is moved to the protruding position where it protrudes into the conveyance path as shown in FIG. Thus, the mechanism including the cam 8 and the drive unit 14 is a positioning unit for the roller cover 5, and the roller cover 5 serves as a stopper as will be described later, and thus is an example of a stopper positioning unit.

When the drive unit 14 drives the cam 8 to return to the position shown in FIG. 2, the cam 8 returns to the state shown in FIG. 2, the roller cover 5 is pulled back by the spring 7, hits the abutting member B and stops at the retracted position. It has become. Note that the cam 8 may return to the state shown in FIG. In addition, the angle formed between the slope 15 in the roller cover 5 and the sheet stacking surface is an acute angle. That is, the sheet bundle falls by its own weight and hits the inclined surface 15 that is the sheet abutting surface, and the sheet leading end aligns and stops accordingly. As a result, the front end of the sheet is slanted so that the lower sheet on the side closer to the feeding roller 3 protrudes more in the sheet conveyance direction, and the positional deviation between the adjacent sheets is lost. To occur. In this way, the roller cover 5 that acts as a stopper makes the sheet bundle rolled up so as to facilitate separation and feeding. That is, the shape of the inclined surface portion is formed so as to cause a positional deviation of the tip between adjacent sheets.

The upstream conveying roller pair 9 is a roller pair that conveys the sheet fed into the apparatus main body by the feeding roller 3 toward the contact image sensor 10. The contact image sensor 10 as an image reading unit is attached so that the two face each other, and reads an image of the sheet conveyed by the upstream conveying roller pair 9. The downstream-side transport roller pair 11 is a roller pair that discharges the sheet that has passed the installation position of the contact image sensor 10 to the outside of the apparatus main body. The sheet discharge tray 12 is a tray on which discharged sheets are stacked. Further, a sheet passage detection sensor 13 for detecting the passage of the sheet is disposed between the upstream side conveyance roller pair 9 and the contact image sensor 10.

Here, the operation when the sheet A is set on the sheet supply tray 2 and fed will be described with reference to FIGS. In the state shown in FIG. 2, when the drive unit 14 rotates the cam 8 under the control of a control unit (not shown), the roller cover 5 is pushed down by the cam 8 and positioned in the state shown in FIG. That is, the sheet that has hit the inclined surface (butting surface) 15 that is in front of the separation nip portion of the roller 3 and the separation roller 4 waits at a position in front of the separation nip portion of the feeding roller 3 and separation roller 4. The roller cover 5 moves to the projecting position where it comes to be. This is called the first position. When the user sets the sheet bundle on the sheet supply tray 2 in this state, as shown in FIG. 3, the leading end portion of each sheet A is abutted against the inclined surface portion 15 of the roller cover 5 by its own weight.

When the roller cover 5 is in the first position as shown in FIG. 3, even when the user performs an operation of stacking the sheet bundle, the slope 15 Becomes a barrier and does not enter the separation nip portion of the feed roller 3 and the separation roller 4. Further, when each sheet A of the sheet bundle hits the inclined surface portion 15 in the roller cover 5, the leading ends thereof are shifted along the inclined surface portion 15, and the leading end portions of the sheet bundle are inclined, and the lower order of the feeding order becomes lower. The more the sheet on the side, the more protruding.

In this state, when the user performs an operation for instructing the start of feeding such as pressing a switch, the drive unit 14 drives the cam 8 under the control of a control unit (not shown), and the roller cover 5 as shown in FIG. Moves to the retracted position (second position). As a result, the restriction on the lowermost portion of the sheet bundle that has been in contact with the inclined surface portion 15 is released. That is, when the cam 8 is moved to the position shown in FIG. 4, the roller cover 5 is rotated about the rotation shaft 6 by the spring 7 and stops at the retracted position where it hits the butting member B. When the roller cover 5 moves to the retracted position, the plurality of sheets A move forward with the leading edges thereof being shifted by the inclined surfaces 15, and for example, a few of the lowermost parts are the feed rollers 3 and the separation rollers 4. Enter the separation nip.

Subsequently, the feeding roller 3 and the separation roller 4 are rotated to start feeding the sheet A. At this time, the front ends of the sheets A of the sheet bundle are shifted, and the lower sheet closer to the feeding roller protrudes to the downstream side. This makes it easy to pull out the lowermost sheet of the sheet bundle by the feeding roller when feeding the sheet.

During the feeding operation, the roller cover 5 is retracted from the conveyance path as shown in FIG. 4, but the leading ends of a number of sheets excluding the lowermost several sheets of the sheet bundle even at the retracted position (second position). Is abutted against the slope portion 15 and has a function of rolling those sheets even during the feeding operation. Further, since the roller cover 4 is retracted from the conveyance path during the feeding operation, the lowermost sheet A fed by the feeding roller 3 is smoothly conveyed without being pressed from the roller cover 4.

The fed sheet A is sent to the image reading position of the contact type image sensor 10 by the upstream conveying roller pair 9, and the image is read by the contact type image sensor 10. The image reading timing is controlled in accordance with the sheet passage timing detected by the sheet passage detection sensor 13. Thereafter, the sheets are sequentially discharged and stacked on the paper discharge tray 12 by the downstream side conveyance roller pair 11.

As described above, according to the present invention, it is possible to realize a sheet feeding apparatus that eliminates the need for the user to throw the sheet bundle when setting the sheet bundle on the sheet feeding tray and has stable feeding performance. be able to.

5 and 6 are a schematic cross-sectional view of the sheet feeding apparatus according to the second embodiment and a perspective view of the roller cover 5. In the present embodiment, the same parts as those in the first embodiment described above are denoted by the same reference numerals, and redundant description is omitted. As shown in FIG. 6, two springs 16 are attached to the free end on the downstream side of the roller cover 5. When the cam 8 is rotated by the drive of the drive unit 14 and the roller cover 5 is pushed down and moved to the protruding position (first position) as shown in FIG. 5, the spring 16 is deformed and the roller cover 5 is moved to the retracted position. It has a function to pull up in the direction. At this time, the leading edge of the sheet abutted against the inclined surface 15 by its own weight is positioned in front of the separation nip of the feeding roller 3 and the separation roller 4 as in the first embodiment. is there. The attachment position of the spring 16 is preferably the free end of the roller cover 5 or the vicinity thereof, but is not limited thereto.

When the sheet bundle is set in the sheet feeding tray in this state, the leading edge of the sheet hits the inclined surface portion 15, and each sheet is wound by its own weight. When the cam 8 rotates to release the pressure on the roller cover 5, the roller cover 5 is lifted by the restoring force of the spring 16 and moved to a retracted position (not shown). At that time, each sheet A advances while the leading edge is shifted by the inclined surface 15, and the lowermost sheet, for example, two or three sheets, enters the separation nip portion of the feeding roller 3 and the separation roller 4. As described above, the retracted position of the roller cover 5 in the present embodiment is a position where the restoring force of the spring 16 is minimized, and the sheet 2 or 3 sheets having a normal thickness in the conveyance path by the movement of the roller cover 5 to the retracted position. A gap that allows the passage of air is made.

In this embodiment, no abutting member is provided, and the mechanism is held at the retracted position by the restoring force of the springs attached to the two free ends on the downstream side of the roller cover 5, so during the sheet feeding operation The position of the roller cover 5 can be changed somewhat. That is, when a thick sheet is fed, the roller cover 5 is easily lifted by the passing sheet, so that it is possible to provide a sheet feeding apparatus corresponding to the feeding of a thick sheet such as a credit card. Further, feeding of wrinkled or curled sheets is facilitated. That is, the spring 16 is an elastic member that allows the roller cover 5 to be displaced from the retracted position by pressing from the passing sheet while holding the roller cover 5 in the retracted position (second position). It is.

  In this embodiment, the spring 16 of the roller cover 5 of the sheet feeding apparatus according to the second embodiment of FIG. 6 can be replaced with a spring having various spring constants. A plurality of roller cover units each having a spring 16 having a different spring constant attached to the roller cover 5 may be prepared, and the roller cover unit may be replaceable. By changing the strength of the spring 16 in this way, it becomes easy to feed a thick sheet or a sheet having wrinkles or curls.

In each of the above embodiments, the separation roller is used as the separation member. However, the separation member may be changed to a separation pad using a friction member such as rubber. In addition, the stopper is effective even when a part of the sheets of the sheet bundle has a shape like a short slope portion that causes a positional deviation between adjacent sheets, and the separation of the sheets Feeding can be made easy enough.

A Sheet B Abutting member 1 Image reading device 2 Paper feed tray 3 Feeding roller 4 Separating roller 5 Roller cover 6 Rotating shaft 7 Spring 8 Cam 9 Upstream conveying roller pair 10 Contact type image sensor 11 Downstream conveying roller pair 12 Ejection Paper tray 13 Sheet passage detection sensor 14 Drive portion 15 Slope portion 16 Spring

Claims (7)

A separation feeding unit having a separation nip part for feeding sheets one by one from a sheet bundle placed on the sheet stacking surface;
In a sheet feeding apparatus having a sheet abutting surface that abuts the leading end of the sheet, and a stopper capable of waiting the sheet in front of the separation feeding unit,
The stopper has a first position where the sheet abutting surface waits for all sheets of the sheet bundle in front of the separation nip portion;
Allowing a part of the sheets of the sheet bundle to enter the separation nip portion, and allowing the remaining sheets to wait on the sheet abutting surface, and is movable to a second position;
The sheet feeding device according to claim 1, wherein the sheet abutting surface has a shape that causes a positional deviation of a leading edge between adjacent sheets with respect to at least a part of the placed sheets. The sheet feeding apparatus according to claim 1, further comprising a stopper positioning unit that positions the stopper at the first position. The stopper holding means which makes the stopper displaceable from the second position by pressing from a passing sheet while holding the stopper at the second position is provided. Sheet feeding device. The sheet according to any one of claims 1 to 3, wherein an angle between the sheet abutting surface and the sheet stacking surface is an acute angle with respect to a sheet conveying direction. Feeding device. The sheet feeding apparatus according to claim 3, wherein the stopper holding unit is an elastic member. 6. The sheet feeding apparatus according to claim 3, wherein the stopper is held at the second position by a restoring force of an elastic member. The separation feeding unit includes a feeding roller and a separation member, the feeding roller is disposed below the sheet to be fed, and the separation member is disposed above the sheet to be fed. The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus is a sheet feeding apparatus.

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