JPH0717285B2 - Sheet feeding device - Google Patents

Description

The present invention relates to a sheet feeding device such as a copying machine, a facsimile, and a laser beam printer, and more specifically, it is formed of a sheet stacking base and a half-moon shaped rotating body. The present invention relates to a sheet feeding device having a wide space to increase a sheet loading amount.

(B) Conventional Technology Conventionally, a sheet feeding device has a circular roller 1 and a separation pad 2 as shown in FIG. 5, and the circular roller 1 is axially supported by a device body (not shown). The separation pad 2 is fixed to a fixed shaft 3 and forms a sheet conveying path. The separation pad 2 is provided at a flat front end of the lower guide plate 5 among the lower guide plates 5 and 5, and is constantly rotated by the spring 6 to form the circular roller 1. And is in frictional contact with the circular roller 1. Further, upstream of the circular roller 1, a sheet mounting table 7 on which the sheet P is mounted is arranged, and the stacking table 7 is biased by a spring 7'to its free end toward the roller 1. . on the one hand,
The sheet stacking base 7 is normally pushed down by a cam 9, and when the sheet P is fed by the circular roller 1, the cam 9 rotates as shown by the arrow and the sheet stacking base 7 rises, The uppermost sheet of the sheets P contacts the circular roller 1 and the sheets are fed. When two or more sheets are fed, the feeding of the lower sheet is regulated by the pressure contact of the separation pad 2 to prevent double feeding of two or more sheets. There is a space for stacking the sheets P between the sheet stacking base 7 and the circular roller 1. The number of sheets that can be stacked on the sheet stacking base 7 is determined by the size of the space, and the cam 9 is set. When the sheet P is rotated and positioned below, the sheets P can be stacked to the maximum, and when a sheet having a size larger than a predetermined value is pushed in, the sheet P interferes with the circular roller 1 and becomes crumpled as shown in the figure. In addition, 10 is a one-way clutch that controls the rotation of the circular roller 1, 11 is the upper and lower guide plates 5,
5 is a pair of conveying rollers disposed downstream of 5.

On the other hand, in the above-described sheet feeding device, since the number of sheets on the sheet stacking base 7 is regulated by the cam 9, the eccentricity of the cam 9 is increased or the guide plate 12 is provided so that the sheet is fed. It is also conceivable to increase the number of sheets loaded on the loading platform 1.

(C) Problems to be Solved by the Invention However, in the above-mentioned conventional apparatus, the vertical movement width of the sheet stacking table 1 due to the rotation of the cam 9 is limited due to its structure, and if the sheet is stacked further. The leading edge of the sheet comes into contact with the circular roller 1 and jams. on the other hand,
In the proposed example in which the above-mentioned conventional apparatus is improved, the space between the circular roller 1 and the sheet stacking base 7 is so large that the arrangement of other apparatuses in the apparatus main body is affected, and space and cost are also reduced. On the contrary, it is disadvantageous.

(D) Means for Solving the Problems The present invention is intended to solve the above-mentioned problems, and is composed of one sheet feeding rotary member on a vertically movable sheet stacking table and a friction member. In the sheet feeding device that separately feeds each sheet, the feeding rotating body is a half-moon shaped rotating body having a cutout portion in which a part of a circumferential portion is cut off, and the cutout portion is formed by a clutch mechanism. It is controlled so as to stop at a predetermined stop position facing the sheet on the stacking table, and a separation pad is arranged facing the feeding rotating body, and is arranged side by side with the feeding rotating body. The feeding rotary member is provided with a double feed preventing means for preventing double feeding of the sheets by contacting the separating pad when the cutout portion of the feeding rotary member faces the separating pad. At the specified stop position, connect the contact points between the missing circle and the circumference directly. A sheet stacking surface extension is constituted an angle larger opening in toward the sheet insertion direction upstream side extension of the sheet stack tray, in a sheet feeding apparatus, characterized in that.

(E) Operation Based on the above configuration, the half-moon-shaped rotary body that rotates in the clockwise direction and feeds the sheets one by one has its stop position controlled by the clutch mechanism. In order to increase the distance between the point on the upstream side in the sheet insertion direction and the point on the downstream side of the contact point between the missing circle portion and the circumferential portion with respect to the downstream side, the sheet surface to be inserted on the sheet stacking table. When the sheet is stacked on the sheet stacking table, the straight line connecting the two contact points and the sheet mounting surface extension line of the sheet stacking table form an angle that opens largely to the upstream side in the sheet insertion direction. When the half-moon shaped rotating body is held in its stop position and the sheet stacking table is pushed downward, the space formed by the half-moon shaped rotating body and the sheet stacking table becomes wide,
The leading edge of the sheet is not curled up or caught in the apparatus, and the sheets are smoothly stacked and the sheet stacking amount is increased.

(F) Embodiment An embodiment in which the present invention is applied to a sheet feeding device of a laser beam printer will be described below with reference to the drawings.

The sheet feeding device, as shown in FIGS.
A half-moon roller 21 is formed by cutting off a part of the circumference to form a substantially flat portion. The half-moon roller 21 is fixed to a shaft 22 and rotates clockwise to feed the sheet P. On both sides of the half-moon roller 21, a pair of idlers 23, 23 are supported by shafts 23 ', 23' which are pivotally supported by a device body (not shown). The separation pad 25 forms a sheet conveying path and is provided on the flat end of the lower guide plate 26 of the lower guide plates 26, 26. The separation pad 25 is provided with a predetermined pressure by the spring force of the spring 27 and the half-moon roller 21 and a pair of idlers. It is in frictional contact with 23,23.
A sheet stacking base 27 'on which the sheet P is placed is disposed upstream of the half-moon roller 21, and the sheet stacking base 27' is provided.
Is urged by a spring 29 toward its half-moon roller 21 at its free end. On the other hand, the sheet stacking base 27 'is normally pushed downward by the cam 30, and when the half moon roller 21 is rotated by the clutch mechanism described later to feed the sheet P, the cam 30 is also driven by the control mechanism (not shown). As it rotates, the sheet stacking base 27 'is pulled upward by the spring force of the spring 29 and pushed up, so that the uppermost sheet comes into contact with a part of the half-moon roller 21 and the sheet is reliably fed. Has become. Further, the shaft 22 of the half-moon roller 21 is provided with a clutch mechanism for controlling the drive and stop positions of the half-moon roller 21, and the clutch mechanism is shown in FIGS.
As shown in Fig. (A), it consists of a spring clutch 31 and a solenoid 32 arranged on the shaft 22, and a half-moon roller is provided for each rotation.
The 21 is stopped at a fixed position and the operation is repeated. Furthermore, the outer casing of the spring clutch 31 is provided with a protrusion 33, and the end of the sliding rod 32 'of the solenoid 32 is
An L-shaped plate-like body 36 having a lower extending portion 35 whose one end extends downward is fixedly provided, and a tension spring 37 is locked to the other end of the L-shaped plate-like body 36. When the solenoid 32 is off, the sliding rod 32 'is moved downward by the spring force of the tension spring 37, and the L-shaped body 36 is also pushed downward.
The lower extension portion 35 is adapted to engage with the protrusion 33 of the spring clutch 31 to stop the spring clutch 31 at a fixed position. Therefore, the half-moon roller 21 is also stopped at a fixed position,
As shown in FIG. 3, the half-moon roller 21 is at the stop position, and the point a on the upstream side in the sheet inserting direction of the contact points a and b between the missing circle portion and the circumferential portion is the point on the downstream side. An extension line of a straight line connecting the contact points a and b and an extension of the sheet mounting surface of the sheet stacking table so that the distance to the sheet surface to be inserted onto the sheet stacking table 27 'becomes larger than b. The line forms an angle with which the line is largely opened upstream in the sheet insertion direction. That is, the half-moon roller 21 connects a point b on the half-moon roller 21 that is close to the straight line in the sheet insertion direction c and a point a on the half-moon roller 21 that first comes into contact with the sheet P when the half-moon roller 21 rotates. It stops at a position where the straight line forms an elevation angle with the sheet insertion direction c. Incidentally, 39 is a pair of conveying rollers which are arranged on the downstream side of the upper and lower guide plates 25, 26 and convey the sheet.

Since this embodiment has the above-described structure, when a start key (not shown) is pressed, an output signal is transmitted to the solenoid 32, the solenoid 32 is turned on, and the sliding rod 32 'is set to the spring of the tension spring 37. L-shaped plate-like body 35 to move upward against force
Also moves up. Then, the lower extension 36 of the L-shaped plate 35 is formed.
And the protrusion 33 of the spring clutch 31 are released,
The half-moon roller 21 fixed to the shaft 22 rotates clockwise.
On the other hand, since the cam 30 also rotates in the clockwise direction by the control mechanism (not shown), the sheet stacking base 27 'moves upward by the spring force of the spring 29. Therefore, the uppermost sheet P on the sheet stacking table 27 'comes into contact with the point a of the half-moon roller 21 rotating clockwise, so that the uppermost sheet P moves downstream due to the contact friction with the half-moon roller 21. Fed, idler 23
And the separation pad 25, passes through a conveying path composed of the upper and lower guide plates 25 and 26 and reaches the conveying roller pair 39, and the uppermost sheet P is further conveyed by the conveying roller pair 39 to the next step. It On the other hand, when the half-moon roller 21 further rotates and the point a of the half-moon roller 21 approaches upward, the solenoid 32 is turned off by a control mechanism (not shown), and the sliding rod 32 'is pulled by the tension spring 37.
Since it moves downward due to the spring force, the lower extension 36 of the L-shaped plate-like body 35 also descends and engages with the protrusion 33 of the spring clutch 31. Therefore, the half-moon roller 21 makes one rotation and stops at a fixed position, and the same operation is repeated thereafter. Further, when the half-moon roller 21 and the separation pad 25 are separated from each other, the idler 23 and the separation pad 25 are in frictional contact with each other even when two or more sheets are fed, so that the lower sheet is separated from the uppermost sheet. Is
Only the topmost sheet is conveyed. When the sheet is stacked on the sheet stacking table 27 ', the half-moon roller 21 comes into contact with the sheet b at the point b on the half-moon roller 21 closest to the straight line in the sheet insertion direction c and the half-moon roller 21 when rotating. Since the straight line connecting the point a on the half-moon roller 21 stops at a position forming an elevation angle with the sheet insertion direction c, the half-moon roller 21
The sheet stacking base 27 'with the cam 30
When the sheet is pushed down by the, the space formed by the half-moon roller 21 and the sheet stacking table 27 'becomes large, so that the leading edge of the sheet is not curled up or caught in the device portion, and the sheet is The sheets are smoothly stacked and the sheet stacking amount is increased.

In this embodiment, since the half-moon roller 21 is used as the sheet feeding roller, the half-moon roller 21 and the separation pad
The idler 23 is provided as a sheet double feed preventing means when the sheet 25 is in a separated state.
It may be provided on the same shaft 22 as. Instead of the idler 23, a smooth member having a small frictional resistance can be used. Further, although the sheet stacking table 27 'has a tray shape, it may be a cassette.

Further, in the half-moon roller 21, if the substantially flat circular portion forming an elevation angle with the sheet insertion direction is smooth and made of a low friction material, even if the sheet comes into contact with the half-moon roller 21, the sheet is smoothly inserted. can do.

FIG. 4 (b) shows another embodiment of the clutch mechanism, in which a plurality of uneven portions 40 are formed on the outer casing of the spring clutch 31, and the half-moon roller 21 is rotated once during one rotation. When it is desired to stop the spring clutch 31, the solenoid 32 is turned off and the lower extending portion 36 of the L-shaped plate-like body 35 is engaged with an arbitrary concave portion of the plurality of concave and convex portions 40. Therefore, the half-moon roller 21 can be stopped at any midway position during one rotation. Furthermore, if the position of the half-moon roller 21 is detected by a sensor or the like, it is possible to stop the half-moon roller at an arbitrary position by using an electromagnetic clutch.

The present invention can be applied not only to a sheet feeding device such as a copying machine, a facsimile and a laser beam printer, but also to a sheet document automatic feeding device.

(G) Effect of the Invention As described above, according to the present invention, the feeding rotary member is
At the stop position, an extension line of a straight line connecting the contact points of the missing circle portion and the circumferential portion and an extension line of the sheet loading surface of the sheet stacking table forms an angle that opens largely toward the upstream side in the sheet insertion direction. Therefore, the space formed by the half-moon-shaped feed rotating body and the sheet stacking base becomes wider, and when the sheet is inserted, the leading edge of the sheet does not curl and the sheets are stacked on the sheet stacking base. It is also possible to increase the sheet stacking capacity.

Further, since the half-moon-shaped feed rotating body is used, it is easy to cause double feeding of sheets, but a separation pad is provided so as to face the feed rotating body, and the feeding pad is arranged in parallel with the feed rotating body. Since the double feed prevention means is provided to prevent the double feed of the sheets by contacting the separation pad when the cut circle portion of the feed rotating body faces the separation pad, the cut circle portion faces the separation pad. However, even if the idler contacts the separation pad, a large amount of sheets can be prevented from entering between the separation pad and the next sheet being fed by the previous sheet, and the sheet can be prevented. It is possible to prevent double feeding.

[Brief description of drawings]

1 is a longitudinal sectional view showing an embodiment of a sheet feeding device, FIG. 2 is a partially cutaway perspective view of FIG. 1, and FIG. 3 is a longitudinal sectional view showing a sheet insertion state in FIG. FIG. 4 (a) is a vertical sectional view showing an embodiment of the clutch mechanism, FIG. 4 (b) is a vertical sectional view showing another embodiment of the clutch mechanism, and FIG. 5 is a conventional sheet feeding device. FIG. 6 is a vertical sectional view showing another conventional sheet feeding device. 21 ... Feeding rotating body (half-moon shaped roller), 23 ... Double feeding prevention means (idler), 25 ... Separation pad, 27 '... Sheet stacking base, 30 ... Cam, 31 ... Spring clutch, 32 ...... Solenoid, 33 ...... Protrusion, 35 ...... L-shaped plate, 36 ...... Lower extension, a, b ...... Contact.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Tadashi Yagi Tadashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yasuyoshi Hayakawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Kya Non-Incorporated (72) Inventor Takeshi Setoriyama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (56) Reference JP-A-61-282237 (JP, A) 187538 (JP, U) Actually open Sho 61-145735 (JP, U)

Claims (2)

[Claims] 1. A sheet feeding device for separating and feeding sheets on a vertically movable sheet stacking table one by one by a feeding rotator, wherein the feeding rotator has a part of a circumferential portion cut off. It is composed of a half-moon shaped rotating body having a cutout portion, and is controlled by a clutch mechanism so that the cutout portion is stopped at a predetermined stop position facing a sheet on the sheet stacking table, and the feeding is performed. A separation pad is arranged opposite to the rotating body, and is arranged side by side with the feeding rotating body. When the cutout portion of the feeding rotating body faces the separating pad, the separating pad comes into contact with the separating pad. A double feed preventing means for preventing double feed is provided, and the feeding rotating body is at the predetermined stop position, and the straight extension line connecting the contact points of the missing circle portion and the circumferential portion and the The extension line of the sheet loading surface of the sheet stacking table is large toward the upstream side in the sheet insertion direction. It constitutes an opening angle formed by a sheet feeding apparatus, characterized in that. 2. The sheet feeding apparatus according to claim 1, wherein the circular portion of the feeding rotary member is made of a smooth and low friction material.