JPH0455236A - Sheet feeding device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper feeder, and particularly to prevention of abnormal noise in a minute mechanism during paper feeding in a rotary paper feeder.

[Conventional technology]

In copying machines and printers, the paper feeding device extracts and separates the recording paper (cup 1 paper) stored in the paper feeder I-, and supplies it to the recording means one by one.The paper feeding device extracts cut paper from the paper cassette. A separating member is provided to press against the paper feed roller and separate the cut sheets extracted by the paper feed roller to prevent double feeding.

Such a paper feeding device is, for example, disclosed in Japanese Utility Model Publication No. 6247545.
It is stated in the No.

[Problem to be solved by the invention]

However, conventional paper feeding devices of this type lack consideration for achieving stable extraction and separation of paper of various types (thickness, surface smoothness, amount of deformation, etc.). 2. In order to prevent abnormal noise from occurring in the separation mechanism during paper feeding, it is necessary to use a limited number of types of cut paper. In particular, if cut paper with a large friction coefficient and high smoothness with the separation member is used, the paper and separation part H
During this time, a stick-slip phenomenon occurred, causing vibration in the paper feeding direction, which was transmitted to surrounding components and caused abnormal noise.

Therefore, an object of the present invention is to provide a paper feeding device that does not generate abnormal noise during paper feeding even when various types of paper are used.

[Means to solve the problem]

A first invention that achieves the above object extracts the cut paper stored in the paper feed cassette with a paper feed roller and passes the cut paper between the paper feed roller and the separating member to remove the extracted cut paper. In a paper feeding device that feeds sheets one by one to a recording means, two contact portions that contact the surface of the paper feeding roller at positions shifted in the paper feeding direction are provided on the separating portion, and the paper feeding device The second method is characterized in that the friction coefficient of the contact portion against the cut paper is made smaller than the friction coefficient of the contact portion on the downstream side.
The invention comprises a paper feed roller that extracts the cut paper stored in the paper feed force cellar 1-, and a separation member that is supported by a support member and is pressed against the paper feed roller. In the paper feeding device which passes the cut sheets extracted from the paper feeding cassette between the paper feeding roller and the paper separation unit and supplies them to the recording means one by one, the separation member is deviated in the paper feeding direction. Two contact portions that contact the paper feed roller surface at positions and an engagement portion that supports the separation member on the support member are provided, and the friction coefficient of the contact portion on the downstream side in the paper feeding direction with respect to the cut paper is set to 1. A friction control layer having a friction coefficient larger than that of the contact portion on the downstream side is formed on the contact portion on the downstream side, and the separation member is configured to swing in the paper feeding direction by the rotational force of the paper feed roller. It is characterized by forming a joint.

[Effect]

Since the separating member presses the cutter 1 and the paper against the paper feeding roller with two contact surfaces, vibration of the separating member and the paper cutter 1 to the paper in the paper feeding direction is suppressed, and generation of abnormal noise is prevented.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 6 shows a laser beam printer using the paper feeding device according to the present invention, in which the surface of the photosensitive drum 1 rotating in the direction of the arrow (A) is uniformly charged by the charger 2, and the surface of the photosensitive drum 1 is uniformly charged by the charger 2, An electrostatic latent image is formed by exposure with a laser beam 4 generated from a beam generator 3 according to a recorded image, and the electrostatic latent image is developed by a developer 5 to become a toner image. The cut paper 8 accommodated in the paper feed force cellars h6 and 7 is indicated by the arrow (
(b) The paper is selectively extracted by the paper feed rollers 9 and 10 rotating in the direction, and the paper feed rollers 9 and 10 are
The cut 1-paper 8 which is overlapped and extracted by passing between the separation parts +J' 13 and 14 pressed by 1o is also separated into sheets one by one, and the paper is fed to the registration roller 15 and stopped. The registration roller 15 aligns the conveyance of the cut sheet 8 with the toner image on the photosensitive drum 1, and restarts the conveyance of the cut sheet 8 at a timing such that both coincide at the transfer position. While the cut paper 8 is being conveyed while being in contact with the photosensitive drum 1 at the transfer position, a bias charge is applied by the transfer device 16, and the toner image on the photosensitive drum 1 is transferred onto the cut paper 8.

The cut paper 8 on which the toner image has been transferred is peeled off from the surface of the photosensitive drum 1 and sent to a fixing device 17. While passing through the fixing device 17, the toner image is fixed and the paper is ejected onto a paper ejection tray 18. Ru. The toner remaining on the surface of the photosensitive drum 1 after the toner image transfer is cleaned by a cleaner 19, and the surface of the photosensitive drum 1 is reused.

Next, details of the paper feeding device according to the present invention will be explained in detail with reference to FIGS. 1 to 5. Since the paper feeding device has the same configuration for the two paper feeding cassettes 6 and 7, the case of the paper feeding cassette 6 will be explained as an example.

In FIGS. 1 to 4, cassette 1- of the paper feed cassette 6
The cut sheets 8 placed and stored on the base 6a are pushed up by the cassette spring 6b, and the uppermost sheet is pressed against the sheet feed roller 9 with a predetermined load (approximately 200 to 350 g). The paper feed roller 9 has a core metal 98 whose outer peripheral surface is covered with a cylindrical high-friction rubber layer 9b, and which is connected to the paper feed shaft 9e by a one-way (overrun) clutch 9c press-fitted into the shaft core and a paper feed metal 9d. It is supported and prevented from coming off by a stopper @9f.

As detailed in FIG. 3, the separation member 3 is formed at a position upstream in the paper feeding direction on the upper surface of the base member 13a made of a material with a relatively low coefficient of friction, extending in a direction perpendicular to the paper feeding direction and having a surface height. a flat friction material adhesive surface 13c formed downstream of the nose portion 13b, and a bifurcated leg portion 1 formed on the lower surface.
3d, pressure springs 13e and 13f fixed to the lower surface, and a high friction coefficient material layer such as urethane foam or cork bonded to the friction material bonding surface 13c so as to be lower than the nose portion 13b. It is equipped with 13g. The leg portion 13
As will be described later, the distal end portion of the separation member 13 is made thinner in order to enable the separation member 13 to swing in the paper feeding direction.

Separation base 2 fixed to paper feed frame 2o with screws 21
Separation member receiver 2 rotatably supported by support shaft 23 on 2
4, the rotating shaft 24a and washers 24, b are attached to the set screw 2.
Fixed by 4c. Then, the legs 13d of the separation member 13 are loosely inserted so as to straddle the rotation shaft 24a, and the separation member 13 is rotatably and swingably supported by the separation base 22. A plurality of pressing springs lla and llb are interposed between the separation base 22 and the separation member receiver 24, and the separation member 13 is pressed against the paper feed roller 9 by rotating the separation member receiver 24 in a clockwise direction. The pressing spring
la and llb are the rotation shafts 24 that support the separation member 13;
On both sides of the paper feed roller 9 and the high friction coefficient material layer 13g are located directly under the contact (1'/H). 24a, and swing the separation member 13 counterclockwise while pushing it up so that only the contact surface formed by the high friction coefficient member layer 13g comes into contact with the paper feed roller 9. Balance the pressing force on the left and right sides in the paper feeding direction.

It is rotatably supported by a support shaft 25a, and is supported by a spring 25b.
A clockwise rotational force is applied to the separation member receiver 24 in a counterclockwise direction to rotate the separation member 1.
3 from the paper feed roller 9 is pushed by the paper feed cassette 6 when the paper feed force sensor 1-6 is attached, and rotates counterclockwise, thereby causing the separation member receiver 24 to rotate clockwise. Allows rotation in direction.

In the above configuration, initially, the separation member 13 is pressed by the pressure spring l.
Pressure springs 13e, 1 are pushed up by la, llb.
3f in the counterclockwise rotation direction and are in the contact state shown in FIG. When the paper feed roller 9 rotates counterclockwise (indicated by the arrow) to feed paper from this contact state, the separation member 13 is clockwise rotated due to the frictional force between the high friction coefficient member layer 13g and the paper feed roller 9. A rotational moment in the rotational direction is applied, and as shown in FIG. 4, it swings clockwise (arrow C).

The cut paper 8 extracted from the paper feed force cellar l-6 by the rotation of the paper feed roller 9 is fed between the paper feed roller 9 and the separating member 13, and the cut paper 8 and the high friction coefficient portion I-6 are fed between the paper feed roller 9 and the separation member 13. 1'M
't ], slippage occurs between 3 g. The friction coefficient μ between the cup I/paper 8 and the high friction coefficient material layer 13g is large (
Generally speaking, the friction coefficient is 0.7 to 0.9), so a stick-slip phenomenon tends to occur between the cut paper 8 and the high friction coefficient material layer 3g. This phenomenon is more likely to occur when ultra-smooth paper is used because the higher the smoothness, the greater the friction coefficient μ. However, as described above, the separation member 1
3 swings clockwise, the separation member 13 presses the cut paper 8 against the paper feed roller 9 at two locations: the nose portion 13b and the high friction coefficient member 913g. However, the occurrence of stick-slip phenomenon is suppressed.

If the separation member 3 is allowed to swing freely in the clockwise direction, the molecular t pressing force on the high friction coefficient member layer 13g decreases, the separation performance deteriorates, and double feeding is likely to occur. The pushing force by the pressure springs 13e and i3f reduces this decrease in the separation pushing force and prevents double feeding from occurring. Moreover, since the pressure springs 13e and 13f are located symmetrically on both sides of the rotating shaft 24a, it is easy to balance the pressing forces on the left and right sides in the paper feeding direction, which has the effect of preventing double feeding as well as misfeed and skew. is obtained.

FIG. 5 shows another embodiment in which the fixing position of the pressure spring is changed. In this example, the pressure spring i 3
h is fixed to the side surface of the leg 1-3d and compressed and interposed between the leg 1-3d and the separation member receiver 24, and the leg 13
Press the side of d firmly to 724-b. Therefore, when the paper feed roller 9 is stopped, the separating section control-3 is in a state of being pressed so as to come into close contact with the washer 24b and swinging in the counterclockwise direction, as shown in FIG. . Then, when the paper feed roller 9 rotates counterclockwise, a clockwise rotational moment is generated in the separation member 13 due to the frictional force between the high friction coefficient member layer 13g and the paper feed roller 9, and as described in the embodiment described above. Similarly, the separating member 13 swings in the clockwise direction to obtain the same effect as described above.

〔Effect of the invention〕

As described in 2 below, since the separating member presses the cut paper against the paper feed roller with two contact surfaces, the vibration of the separating member and the cut paper in the paper feeding direction is suppressed, and therefore, the cut paper with a high coefficient of friction is suppressed. No abnormal noise is generated even when paper is used.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which FIG. 1 is a vertical side view of the paper feeding device, FIG. 2 is a perspective view thereof, and FIGS. 3 and 4 are vertical side views showing details of the separation member. , FIG. 5 is a longitudinal sectional side view showing another embodiment of the separating member, and FIG. 6 is a side view of a laser beam printer using the paper feeding device according to the present invention. 6.7...Paper feed cassette 8...Cut paper, 9.10...Paper feed roller, 9a Core bar, 9b
---High friction rubber layer, 1]-a, 1.
], l) Pressing spring, 1.3.14... Separation member, 1-38 Heath member, 1.3 b
North part, 130 Frictional adhesive surface, 13d
Legs, 13e, 13f...pressure springs, 1
3g...High friction coefficient member layer, 24... Separation part 4 receiver, 24-a... Rotation shaft.

Claims (1)

[Claims] 1. Recording means for extracting cut sheets stored in a paper feed cassette with a paper feed roller and passing the extracted cut sheets one by one between the paper feed roller and a separating member. In the paper feeding device, the separation member is provided with two contact portions that contact the surface of the paper feed roller at positions shifted in the paper feeding direction, and the friction coefficient of the contact portions on the upstream side in the paper feeding direction with respect to the cut paper is adjusted. A paper feeding device characterized in that the coefficient of friction is smaller than the coefficient of friction of the contact portion on the downstream side. 2. In claim 1, the separation member comprises a separation base made of a low friction coefficient material and a high friction coefficient material layer formed on the separation base at a position providing the downstream contact portion. Paper feed device. 3. The paper feeding device according to claim 1 or 2, wherein the separating member is provided so as to be swingable in the paper feeding direction. 4. A paper feed roller that extracts the cut paper stored in the paper feed cassette, and a separation member that is supported by a support member and pressed against the paper feed roller, and the cut paper is extracted from the paper feed cassette by the paper feed roller. In a paper feeding device that passes the cut sheets that have been removed and supplies them to the recording means one by one by passing between the paper feeding roller and the separating member, the separating member contacts the surface of the paper feeding roller at a position shifted in the paper feeding direction. and an engaging portion for supporting the separating member on the supporting member, and the friction coefficient of the contact portion on the downstream side in the paper feeding direction with respect to the cut paper is made larger than the friction coefficient of the contact portion on the upstream side. A sheet feeder characterized in that a friction member layer is formed on the contact portion on the downstream side, and the engaging portion is formed so that the separating member can swing in the sheet feeding direction by the rotational force of the sheet feeding roller. Device. 5. In claim 4, an elastic body is interposed between the separating member and the supporting member, and the separating member allows the contact portion on the downstream side in the paper feeding direction to contact the surface of the paper feeding roller. A paper feeding device characterized in that it is pressurized in a direction in which it is pressed.