JP3591214B2 - Paper feeder - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sheet feeding device. For example, the present invention relates to a paper feeder for feeding paper to an image forming apparatus such as a printer, a copying machine, and a facsimile, and more particularly, to improvement of a hopper cam.
[0002]
[Prior art]
2. Description of the Related Art As a conventional paper feeder, for example, a paper feeder as shown in FIG. 2A is known (JP-A-5-301644).
[0003]
In FIG. 2A, reference numeral 1 denotes a paper feed roller, which comes into contact with and feeds a sheet (not shown). The paper feed roller 1 is not shown in the figures of the above-mentioned publications, and is added by the present applicant.
[0004]
Reference numeral 2 denotes a hopper on which sheets (not shown) to be fed are placed. The hopper 2 is constantly urged toward the paper feed roller 1 by a hopper spring (compression spring) 3. The operation is that a part (cam follower portion) 2 a of the hopper 2 is in contact with the cam 4. Regulated by
[0005]
The cam 4 is fixed to a cam shaft 5, and the cam surface includes a separation surface 4 a for separating the hopper 2 from the paper feed roller 1, and a movement surface for moving the hopper 2 toward the paper feed roller 1. 4b.
[0006]
Therefore, when the cam follower portion 2a is in contact with the separation surface 4a of the cam 4, the movement of the hopper 2 toward the paper feed roller 1 is restricted, and the cam 4 rotates in the direction of the arrow shown in the drawing to move the cam follower portion 2a. When it comes off the separation surface 4a, it moves toward the paper feed roller 1 and moves the paper (paper to be fed) (not shown) placed on the hopper toward the paper feed roller 1 by the urging force of the hopper spring 3. Crimp. Further, when the cam 4 rotates, the cam 4 again comes into contact with the separating surface 4a and is pushed down (separated from the sheet feeding roller 1). That is, the cam 4 regulates the movement and the separation operation of the hopper.
[0007]
In the paper feeder having such a structure, when the cam follower portion 2a of the hopper 2 comes off the separating surface 4a and the hopper 2 moves rapidly toward the paper feed roller 1, the hopper 2 There is a problem that the collision sound when colliding with No. 1 increases.
[0008]
In order to solve this problem, in the conventional apparatus shown in FIG. 2A, a member 6 having a high coefficient of friction is provided on the moving surface 4b of the cam 4 for moving the hopper 2 toward the paper feed roller 1. Thus, means for controlling the rising speed of the hopper 2 is taken.
[0009]
[Problems to be solved by the invention]
However, the above-described conventional paper feeding device (FIG. 2A) has the following problem.
[0010]
When the cam 4 is driven by a gear train, for example, as schematically shown in FIG. 2B, when a gear 7 is fixed to a cam shaft 5 and driven by a drive gear 8, there is a backlash B. In the conventional apparatus, the cam follower portion 2a of the hopper 2 immediately comes into contact with the moving surface 4b immediately after the cam follower portion 2a comes off the separating surface 4a, but the cam follower portion 2a is brought into contact with the moving surface 4b. Immediately after the contact, the cam 4 rotates by the backlash B in the direction of the arrow by the urging force of the hopper spring 3, and as a result, a reliable sliding contact between the cam follower portion 2a and the moving surface 4b is obtained. There is a risk of disappearing.
[0011]
That is, in the conventional apparatus, there is a possibility that the hopper 2 suddenly collides with the paper feed roller 1 and the collision noise is increased.
[0012]
An object of the present invention is to solve the above-described problems and to provide a sheet feeding device capable of reliably reducing the collision sound.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the paper feeding device according to claim 1 includes a paper feeding roller that contacts and feeds the paper.
A hopper that is configured to be movable toward and away from the paper feed roller, and presses the paper to be fed toward the paper feed roller when moved toward the paper feed roller;
A cam defining the movement and separation of the hopper;
A cam follower portion which comes into contact with the cam surface of the cam,
A gear train for rotating the cam,
A cam surface of the cam, a separating surface for separating the hopper from the sheet feeding roller, a moving surface for gently moving the hopper toward the sheet feeding roller, and a moving surface for moving the hopper toward the sheet feeding roller. And a surface for removing backlash in the gear train between the gears.
[0014]
[Effects]
According to the sheet feeding device of the first aspect, the sheet feeding roller is configured to be in contact with and feed the sheet, and to be movable toward and away from the sheet feeding roller and move toward the sheet feeding roller. A hopper that presses the paper to be fed toward the paper feed roller, a cam that regulates the movement and separation of the hopper, a cam follower that contacts the cam surface of the cam, and the cam. When the hopper moves or separates toward the paper feed roller by the cam rotated by the gear train, and moves toward the paper feed roller, the paper is pressed against the paper feed roller. It is sent.
[0015]
According to the sheet feeding device of the first aspect, the cam surface of the cam is provided with a separating surface for separating the hopper from the sheet feeding roller, and the cam surface is gently moved toward the sheet feeding roller. The cam follower portion is separated from the separating surface since the moving surface has a removing surface that removes backlash in the gear train between the separating surface and the moving surface. Before the contact with the moving surface is started, it comes into contact with the removal surface, and the backlash in the gear train is removed by the contact with the removal surface.
[0016]
In other words, according to the sheet feeder of the first aspect, the backlash is removed before the cam follower portion comes into contact with the moving surface, so that the cam follower portion and the moving surface are reliably brought into contact (sliding contact). As a result, the moving surface is configured to move the hopper gently toward the paper feed roller, so that the hopper surely moves gently toward the paper feed roller. It is possible to reliably reduce the sound of the collision with the paper feed roller.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0018]
1 (a) to 1 (c) and (b ') and (c') show a main part of an embodiment of a sheet feeding device according to the present invention, and are also diagrams for explaining the operation.
[0019]
In the drawing, reference numeral 10 denotes a paper feed roller (see FIG. 3C), which is a D-shaped roller having a circular arc portion 11 and a linear portion 12 when the circular arc portion 11 comes in contact with a sheet (not shown). Feed. The paper feed roller 10 is fixed to a paper feed roller shaft 13 and is rotationally driven by a gear train as shown in FIG. As shown in FIG. 1B, a gear 14 is fixed to the paper feed roller shaft 13, and the gear 14 (ie, the shaft 13) is driven to rotate by a drive gear 15.
[0020]
Reference numeral 20 denotes a hopper on which sheets to be fed (not shown) are placed. The hopper 20 is constantly urged toward the paper feed roller 10 by a hopper spring (compression spring) 21. The operation of the hopper 20 is performed at the ends of the hopper 20 (both ends in a direction orthogonal to the plane of FIG. 1). The cam follower portion 22 is regulated by being in contact with the cam 30.
[0021]
The cams 30 are fixed to both ends of the paper feed roller shaft 13, and the cam surfaces thereof include a separation surface 31 for separating the hopper 20 from the paper feed roller 10 and a hopper 20 facing the paper feed roller 10. A moving surface 33 for gently moving, and a removing surface 32 between the separating surface 31 and the moving surface 33 for removing backlash B (see FIGS. (B ′) and (c ′)) in the gear train. have. In this embodiment, the separating surface 31 is formed by an arc surface centered on the paper feed roller shaft (that is, the cam shaft) 13, and the moving surface 33 moves the hopper 20 toward the paper feed roller 10 gently. It is formed with such a gentle curved surface. The removal surface 32 is formed of a curved surface that smoothly connects between the separation surface 31 and the movement surface 33.
[0022]
The operation of such a paper feeder is as follows.
[0023]
(I) In a standby state (during a non-feeding operation), the cam follower portion 22 of the hopper 20 is in contact with the separation surface 31 of the cam 30 as shown in FIG. Therefore, the hopper 20 is separated from the paper feed roller 10 in a state where the movement toward the paper feed roller 10 is restricted.
[0024]
(Ii) During the sheet feeding operation, the cam 30 rotates in the direction of the arrow as shown in FIG. In this case, the cam 30 is rotationally driven by the drive gear 15 via the gear 14 and the paper feed roller shaft 13 (cam shaft) as shown in FIG. Causes backlash B as shown in FIG.
[0025]
(Iii) When the cam 30 further rotates and the cam follower portion 22 separates from the separating surface 31 and comes into contact with the removing surface 32 as shown in FIG. Rotate as shown by a. At this time, as shown in FIG. 9C, the rotation is performed by the amount of the backlash B, and as a result, the backlash B is removed.
[0026]
Thereafter, the cam follower portion 22 comes into contact (sliding contact) with the moving surface 33, and the hopper 20 moves gently toward the paper feed roller 10.
[0027]
The rotation of the cam 30 by the backlash B in the direction of the arrow a due to the contact of the cam follower portion 22 with the removal surface 32 shown in FIG. The rotation of the cam 30 until the hopper 20 comes into contact with the paper feed roller 10 from this point onward is due to the urging force of the hopper spring 21 because the cam follower portion 22 is in contact with the cam. Will be obtained by Therefore, in such a state, the drive gear 15 acts to restrict the cam 30 from over-rotating and to make the cam follower portion 22 abut against the moving surface 33 reliably.
[0028]
After the hopper 20 moves and comes into contact with the paper feed roller 10 (not shown), the cam 30 and the paper feed roller 10 are further mounted on the hopper 20 by rotating with the power from the drive gear 15. The paper (not shown) is pressed against the paper feed roller 10 by the urging force of the hopper spring 21, and the paper is fed by the paper feed roller 10.
[0029]
By the further rotation of the cam 30, the separating surface 31 comes into contact with the cam follower portion 22 again, so that the hopper 20 is separated from the sheet feeding roller 10 as shown in FIG.
[0030]
As described above, according to the paper feeding device, the paper feeding roller 10 is configured to be in contact with and feed the paper, and to be movable toward and away from the paper feeding roller 10. 10, a hopper 20 for pressing the paper to be fed toward the paper feed roller 10, a cam 30 for regulating the movement and separation of the hopper 20, and a cam surface of the cam 30. And the gear trains 14 and 15 for rotating the cam 30, the hopper 20 is moved toward or away from the paper feed roller 10 by the cam 30 rotated by the gear trains 14 and 15. When the paper is moved toward the paper feed roller 10, the paper is pressed against the paper feed roller 10 and fed.
[0031]
According to the sheet feeding device of the present embodiment, the cam surface of the cam 30 has a separating surface 31 for separating the hopper 20 from the sheet feeding roller 10, and the hopper 20 is gently moved toward the sheet feeding roller 10. And the removal surface 32 between the separation surface 31 and the movement surface 33 for removing the backlash B in the gear trains 14 and 15. After coming off from the separating surface 31, before coming into contact with the moving surface 33, it comes into contact with the removing surface 32, and by this contact with the removing surface 32, the backlash B in the gear trains 14, 15 is removed. Will be done.
[0032]
That is, according to the sheet feeding device of this embodiment, the backlash B is removed before the cam follower portion comes into contact with the moving surface 33, so that the cam follower portion 22 and the moving surface 33 are reliably brought into contact ( (Sliding contact) state is obtained, and the moving surface 33 is configured to move the hopper 20 gently toward the paper feed roller 10, so that the hopper 20 reliably moves gently toward the paper feed roller 10. As a result, as a result, the collision noise when the hopper 20 collides with the paper feed roller 10 can be reliably reduced.
[0033]
As described above, one embodiment of the present invention has been described, but the present invention is not limited to the above embodiment, and can be appropriately modified and implemented within the scope of the present invention.
[0034]
For example, in the above-described embodiment, the removal surface 32 is a curved surface.
[0035]
【The invention's effect】
According to the present invention, the collision sound when the hopper collides with the paper feed roller can be reliably reduced.
[0036]
[Brief description of the drawings]
1 (a) to 1 (c) and (b ′) and (c ′) show a main part of an embodiment of a sheet feeding device according to the present invention, and are also diagrams for explaining the operation. .
FIGS. 2A and 2B are explanatory diagrams of a conventional technique.
[Explanation of symbols]
B Backlash 10 Feed rollers 14 and 15 Gear train 20 Hopper 22 Cam follower 30 Cam 31 Separation surface 32 Removal surface 33 Moving surface

Claims (1)

A paper feed roller for contacting and feeding the paper;
A hopper that is configured to be movable toward and away from the paper feed roller, and presses the paper to be fed toward the paper feed roller when moved toward the paper feed roller;
A cam defining the movement and separation of the hopper;
A cam follower portion which comes into contact with the cam surface of the cam,
A gear train for rotating the cam,
A cam surface of the cam, a separating surface for separating the hopper from the sheet feeding roller, a moving surface for gently moving the hopper toward the sheet feeding roller, and a moving surface for moving the hopper toward the sheet feeding roller. A sheet removing device for removing a backlash in the gear train between the sheet feeding device and the sheet feeding device.

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