JPH082724A - Feeding device and image forming apparatus - Google Patents

Abstract

PURPOSE:To provide a feeding device with which determination of energizing force of a torque limiter and a separating roller to a feed roller can on multiple be facilitated and defective feeding such as duplicate feeding and jamming can be prevented. CONSTITUTION:Transfer paper sheets P being stacked as sheet material is separated one by one to be fed by this device, which is provided with a paper feed roller 1 as a feed roller for feeding the transfer paper sheet P and two separating rollers 13, 14 for separating and feeding the transfer paper sheet P. The separating rollers 13, 14 are rotated at a peripheral speed not higher than a peripheral speed of the paper feed roller 1 in the direction of feeding the transfer paper sheet P.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a sheet feeding apparatus that separates and feeds sheet materials one by one by a stacking unit that stacks and stocks sheet materials of an image forming apparatus for forming an image on the sheet materials. Regarding the device.

[0002]

2. Description of the Related Art Heretofore, a so-called retard system has been widely used as a feeding device of an image forming apparatus that feeds a transfer sheet as a sheet material from a stacking section or the like. This conventional example will be described with reference to FIG. Reference numeral 101 is a paper feed roller, 102 is a separation roller, 103 is a pickup roller, and 104 is a lever rotatably supported by a shaft 105 and is a lever for detecting the paper surface height of the transfer paper P ′. The paper feed roller 101 is fixed to a shaft 105, and the shaft 105 is rotatably supported by the apparatus main body by a bearing (not shown). Pickup roller 103
Is rotatably supported by a support plate 107 via a bearing 106, and the support plate 107 is rotatably supported by a shaft 105 via a bearing (not shown). Then, the support plate 107 is rotated up and down by the action of a solenoid (not shown) so that the pickup roller 103 drops from the position shown in FIG. The separation roller 102 is movably supported by a support 108 via a bearing (not shown), and a lever 110 rotatably supported by a support shaft 109 and a roller 111 rotatably supported by the lever 110. Then, the spring 112 urges it toward the paper feed roller 101 and contacts the paper feed roller 101. The paper feed roller 101, the separation roller 102, and the pickup roller 103 are given rotational force to rotate in the directions of arrows a, b, and c, respectively, by the drive force of a drive source (not shown). A torque limiter (not shown) is provided between the drive source and the separation roller 102, and the separation roller 1 is provided from the outside.
When the force 02 is applied in the direction opposite to the direction of the arrow b and the torque exceeds the set value of the torque limiter, the separation roller 102 starts to rotate in the direction opposite to the direction of the arrow b. Now, the solenoid (not shown) rotates the pickup roller 103 dropped on the surface of the transfer sheet P ′, and the transfer sheet P ′ (often a plurality of sheets) is transferred to the nip portion between the sheet feeding roller 101 and the separation roller 102. Will be sent. When the paper feed roller 101 and the separation roller 102 are in direct contact with each other or when only one transfer sheet P ′ is sandwiched in the nip, the paper feed roller 101 and the separation roller 102, and the paper feed roller 101 and the transfer sheet P ′, The frictional force between the transfer paper P ′ and the separation roller 102 is large and overcomes the torque of the torque limiter to rotate the separation roller 102 in the direction opposite to the arrow b. In addition, 2 between the paper feed roller 101 and the separation roller 102.
When more than one transfer sheet P'is sandwiched, the separating roller 1 cannot overcome the torque limiter due to the frictional force between the transfer sheets P '.
02 rotates in the direction of arrow b. Therefore, the paper feed roller 1
Only the transfer paper P ′ on the 01 side is sent out, and the other transfer paper P ′ is returned to the upstream side by the separation roller 102. As a result, the transfer sheets P'can be separated and fed one by one.

[0003]

However, the torque limiter, the urging force of the separation roller 102 to the paper feed roller 101, etc. may be affected by the thickness, surface condition, cutting condition, and environment of the transfer paper P '. Change, the setting range is limited,
The margin is reduced and it becomes difficult to set properly. If the setting value is different, it causes double feed, jam, etc. Therefore, as shown in FIG. 4, it is considered that the separation roller 102 is made of sponge and the nip portion between the separation roller 102 and the paper feeding roller 101 is widened to stabilize the separation of the transfer paper P ′. However, in this method, the separation roller 102 made of sponge is apt to deteriorate, and the amount of paper dust and the like is also increased, and the frictional force of the separation roller 102 with respect to the transfer paper P ′ is reduced, resulting in a shorter life. .

The present invention has been made to solve the above-mentioned problems of the prior art. The object of the present invention is to easily set the urging force of the torque limiter and the separation roller to the feeding roller, and An object of the present invention is to provide a feeding device capable of preventing double feeding of materials, feeding defects such as jams.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, a sheet feeding device that separates stacked sheet materials one by one and feeds the sheet material is fed. A feeding roller; and at least two separating rollers that contact the feeding roller to separate and feed the sheet material, the separating roller feeding the sheet material in a feeding direction. The roller is characterized by rotating at a peripheral speed equal to or lower than the peripheral speed of the roller.

The peripheral speed of the separating roller on the upstream side is preferably higher than that on the downstream side.

A torque limiter is provided on the separation roller,
The set value of the torque limiter can be changed by each separating roller.

[0008]

In the feeding device configured as described above, the number of contact points with the feeding roller is increased by at least two separating rollers that separate and feed the sheet material. Since the roller rotates at a peripheral speed equal to or lower than the peripheral speed of the feeding roller in the feeding direction of the sheet material, a force relatively acts on the feeding roller in the direction of separating the sheet material.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments.

1 and 2 show an embodiment of the present invention. Reference numeral 1 is a paper feed roller as a feed roller, 3 is a pickup roller, and 4 is a lever rotatably supported by a shaft 5, and is a lever for detecting the paper surface height of the transfer paper P. The paper feed roller 1 is fixed to a shaft 5, and the shaft 5 is rotatably supported by the apparatus main body by a bearing (not shown). The pickup roller 3 is rotatably supported by a support plate 7 via a bearing 6,
Is rotatably supported by the shaft 5 via a bearing (not shown). The support plate 7 is rotated up and down by the action of a solenoid (not shown) so that the pickup roller 3 drops onto the surface of the transfer sheet P as a sheet material from the position shown in the figure at the time of sheet feeding.

Separation roller 1 in contact with paper feed roller 1
3, 14 are rotatably supported by a support member 15. The support member 15 is supported by a shaft 17 fixed to a support base 16 so as to be vertically movable, and a lever 10 rotatably supported by a support shaft 9, and a roller 1 rotatably supported by the lever 10.
1 through a spring 12 to separate rollers 13, 14
Is urged to the paper feed roller 1. FIG. 2 is a diagram illustrating a drive transmission path in which a supporting member such as a bearing is omitted. The paper feed roller 1 is rotated by being transmitted from a drive source (not shown) to the timing belt 18, the timing pulley 19, and the shaft 5. Also axis 5
The torque limiter 2 via the timing pulley 20, the timing belt 21, and the timing pulleys 22 and 23.
Rotational force is transmitted to the separation rollers 13 and 14 from the couplings 26 and 27 to the separation rollers 13 and 14.

The number of teeth of the timing pulley 22 is smaller than that of the timing pulley 23, and the separating roller 13 rotates faster than the separating roller 14. As a result, the transfer paper P sent by the pickup roller 3 is separated between the paper feed roller 1 and the separation roller 13, and some transfer papers P that could not be separated are separated between the paper feed roller 1 and the separation roller 14. They are separated and fed one by one. At this time, when the paper feed roller 1 and the separation roller 13 cannot be separated completely, and when the paper feed roller 1 and the separation roller 14 are about to separate, the separation roller 13 also works to separate the transfer paper P, and further the separation is performed. Since the speed is higher than that of the roller 14, the excess transfer paper P is returned to the upstream side so that the excess transfer paper P is not left in the nip portion between the paper feed roller 1 and the separation roller 14, and the upstream side of the separation roller 14 is prevented. It assists the function of separating the transfer paper P that could not be separated.

Although there are two separating rollers in this embodiment, three or more separating rollers may be arranged. However, since there is only one paper feed roller, the size of the device must be increased and the size of the device must be increased.

(Other Embodiments) In the previous embodiment, the number of teeth of the timing pulleys 22 and 23 is changed to separate the separation roller 1
Although the speeds of 3 and 14 are different, it is possible to set the torque limiter differently even if the speeds are the same. That is, the resistance torque of the separation roller 13 is set to be smaller than the resistance torque of the separation roller 14 to make the separation performance different, and the latitude of the separation ability can be expanded by the stepwise separation. (First-stage separation, second-stage separation ... Pre-separation method of use), this embodiment can be made more effective by combining with the previous embodiment.
As a result, the torque of the torque limiter, the urging force to the paper feed roller 1 and the like can be reduced, so that the durability such as the life of the separation roller can be increased.

[0015]

According to the present invention, at least two separating rollers for separating and feeding the sheet material increase the number of contact points with the feeding roller, and the feeding force is stable. Further, since the separating roller rotates at a peripheral speed equal to or lower than the peripheral speed of the sheet feeding roller in the sheet feeding direction, a force acts relatively on the sheet feeding roller in the direction of separating the sheet material. Since they rotate in the same direction, wear is reduced.

Further, by setting the peripheral speed on the upstream side of the separation roller to be higher than that on the downstream side, it becomes easier to cope with the difference in frictional force between the sheet materials, and the separation efficiency can be improved.

On the other hand, by providing the separating roller with a torque limiter and changing the set value of the torque limiter for each separating roller, it becomes easier to cope with the difference in frictional force between the sheet materials and the separating efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of a feeding device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a paper feed roller-related transmission path of the feeding device according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a conventional feeding device.

FIG. 4 is a cross-sectional view showing another conventional feeding device.

[Explanation of reference symbols] P, P 'Transfer paper (sheet material) 1,101 Paper feed roller (feed roller) 3,103 Pickup roller 13,14,102 Separation roller 24,25 Torque limiter

Claims (4)

[Claims] 1. The stacked sheet materials are separated one by one,
In a feeding device for feeding, a feeding roller that feeds a sheet material, and at least two separating rollers that contact the feeding roller to separate the sheet material and feed the sheet material, The feeding device, wherein the separating roller rotates in a direction of feeding the sheet material at a peripheral speed equal to or lower than a peripheral speed of the feeding roller. 2. The feeding device according to claim 1, wherein the separation roller has a higher peripheral speed on the upstream side than on the downstream side. 3. The feeding device according to claim 1, wherein the separating roller is provided with a torque limiter, and the set value of the torque limiter is changed by each separating roller. 4. An image forming apparatus comprising: the feeding device according to claim 1; and an image forming unit that forms an image on a sheet material fed by the feeding device. .