JPS62157145A - Paper sheet feeding device - Google Patents

Abstract

PURPOSE:To prevent the poor feed of a sheet due to excessive slack curve, by providing a detecting means which detects that a given amount of slack curve occurs to the sheet. CONSTITUTION:When slack curve C is increased to a given value, a hole 12b of an upper guide plate 12 is closed with a sheet P having the slack curve part. In which case, the closing is immediately detected by a sheet sensor 18, and electromagnetic clutch is immediately disengaged. The disengagement stops rotation driving of a sheet handling roller 3 is stopped. As noted above, when the slack curve C of the sheet P between the sheet handling roller 3 and a resist roller 16 is increased to a given value, rotation driving of the sheet handling roller 3 is immediately stopped. This stop prevents excessive increase of the slack curve C, and prevents the tip part of the sheet P from slipping off from a contact part between the resist roller 16 and roller elements 14 and 15.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a paper feeding device incorporated in an image forming apparatus such as a copying machine or a printing machine, and particularly relates to a paper feeding device that does not feed cut sheets one by one to an image forming processing section. Related to paper feeding device.

BACKGROUND TECHNOLOGY A paper feeding device incorporated in an image forming apparatus such as a copying machine or a printing machine generally includes a paper separating roller that is selectively driven to rotate a plurality of sheets of paper placed on a paper feeding tray. The sheet is taken out by a roller and conveyed to a registration roller, and the sheet is conveyed to the image formation processing section by the registration roller at a predetermined time synchronized with the operation of an image formation processing section such as a plate cylinder or a photosensitive drum for copying. A paper feeder of this type having the structure J5 is shown in, for example, Japanese Patent Publication No. 58-7582.

Problems to be Solved by the Invention In the paper feeding device as described above, the registration rollers are used to feed the paper to the image forming processing section at a predetermined time, and the paper is fed diagonally during the conveyance process. Paper (Z1)
In order to eliminate the
The rotation drive timing of the paper separation roller is controlled so that the leading edge of the paper reaches Y1 at the contact portion of the registration roller, and even after the leading edge of the paper reaches the registration roller, the paper separation roller continues to move the paper for a short time. transportation is now taking place.

Therefore, in the above-mentioned paper feeding device, the paper is conveyed from the paper feed stand to the registration rollers by the paper separation rollers, and the paper is not separated until it is conveyed to the image forming processing section by the registration rollers. Looseness and curvature occur between the roller and the registration roller in the conveyance direction. A moderate amount of slack curvature is useful for eliminating the tilt of the paper caused by slanted feeding during the conveyance process, but if this slack curvature becomes too large, the leading edge of the paper will be closer to the contact area with the resist 1 cola. 1
Paper may be pulled out, and when this extraction occurs, a paper feeding failure occurs.

Conventionally, in the above-mentioned four-way paper feeding device, the paper separation roller is rotated by a predetermined constant angle each time a sheet of paper is taken out, and for this reason, the paper separation roller is driven to rotate by a predetermined fixed angle each time a sheet of paper is taken out. The amount of paper carried by the paper separation rollers may vary due to differences in frictional resistance between the paper separation rollers and the registration rollers. During this time, the magnitude of the slack curvature that occurs in the paper changes, and there is a risk that this slack curvature will become too large. In particular, when paper is supplied to the image forming processing unit for multi-color printing, as color printing progresses, the friction coefficient between the paper sheets that are clasped together decreases, so the amount of paper to be conveyed by the paper separation roller increases. However, the slack and curvature that occurs in the paper tends to increase.

This Komei prevents the paper from becoming excessively loose and curved.
The object of the present invention is to provide an improved paper feeding device that avoids paper feeding failures caused by excessive slack and curvature.

Means for Solving the Problems According to the present invention, a plurality of sheets of paper placed on a paper feed tray are taken out one by one by a paper sorting row that is selectively driven to rotate. In a paper feeding device that conveys the paper to the registration rollers and conveys the paper to the image forming processing section at a predetermined timing by the registration rollers, the paper is placed between the paper separation roller and the registration rollers. a detection means for detecting the occurrence of a fixed amount of slack curvature;
*) Rotation drive of the paper sorting roller due to output/! This is achieved by a paper feeding device having a rotation stop means for stopping the rotation.

Effects and Effects of the Invention According to the above-described configuration, the rotational drive of the paper separation roller is directly stopped in accordance with the magnitude of the paper 0 slack curvature that occurs between the paper separation roller and the registration roller. A 1° embodiment in which it is possible to reliably prevent the occurrence of slack and curvature of more than a predetermined amount in the paper for recording purposes, and to prevent paper feeding failures from occurring due to excessive sag and curvature of the paper. The invention will now be described in detail by way of example embodiments with reference to the accompanying drawings.

1 and 2 illustrate one embodiment of a five-sheet feeder according to the present invention. In these figures, reference numeral 1 indicates a paper feed tray, on which a plurality of sheets of paper P are stacked, and which is moved vertically in the figures by a drive device (not shown). It is designed to be driven. A front wiJ wall plate 2 is provided upright at the front end of the paper feed tray 1 in the paper feeding direction, that is, on the right side in the figure, and the front wall plate is connected to the paper feed tray. The front edge of the sheet P placed on the sheet P is positioned.

A paper separating roller 3 made of rubber or rubber-like material is provided above the front wall plate 2. The paper sorting roller 3 is rotatably supported by a support shaft 4 from a side plate 5. The support shaft 4 is drivingly connected to the ffH magnetic hoe clutch 6 transmission belt 7 at one end thereof, and the electromagnetic clutch 6
Only when C1 is in the engaged state, C1 is rotated in the counterclockwise direction as seen in FIG. As a result, the paper sorting roller 3 is moved to the first position when the electromagnetic clutch 6 is in the engaged state.
It is rotated counterclockwise as seen in the figure.

A paper separating pad holder 8 is provided at the upper end of the front partition wall plate 2 so as to face the paper separating roller 3.

The paper separating pad boulder 8 is supported by a bracket 9 so as to be movable in the radial direction of the paper separating roller 3, and is urged toward the outer peripheral surface of the paper separating roller 3 by the spring force of a compression coil spring 10. A paper-separating band 11 is attached to the upper surface of the paper-separating pad holder 8, that is, the surface facing the outer circumferential surface of the paper-separating 1 cola C3, and the paper-separating pad has the following features:
It is made of a material with a relatively low friction coefficient, such as rubber or a rubber-like product or cork, and is opposed to the outer periphery of the paper separating roller 3.

A lower guide 1fi 2 a and an upper guide plate 12 provide a feeder to the front side of the paper separating roller 3 in the paper feeding direction, that is, to the side of the plate IgA 25, which is an image forming processing section, and the corresponding press roller 2G. A paper passage 13 is provided. The paper feed passage 13 extends from the paper handling cola 3 toward the image forming processing section, and a registration roller 16 consisting of a pair of upper and lower roller elements 14 and 15 is provided near the end thereof. There is.

[1-The roller elements 14 and 15 are in contact with each other, and the roller element 14 is selectively driven to rotate clockwise in the figure by a drive device (not shown).

The upper guide plate 12 has a paper sorting roller 3 and a registration roller 16.
The t8 paper path 13 is curved upward in order to prevent the paper P from loosening and curving in the conveyance direction as shown in the figure. In fishing, it is spreading vertically in the figure. A hole 12b is provided in the curved portion 12a of the upper guide plate 12, and a reflective photoelectric paper sensor 18 is provided in the upper guide plate 12 by brackets 1 to 17. It is detected that the paper P contacts the curved portion 12a of the guide plate 12 and the hole 12b is closed by the paper, and 7L12b sends a signal to release the electromagnetic clutch 6 (opening closed by P). It is designed to output to the electromagnetic clutch 6.

When the electromagnetic clutch 6 is connected during paper feeding, paper separation [
] - The roller 3 is rotated in the counterclockwise direction in the figure, and as a result, the topmost sheet of paper P on the paper feed tray 1 is rotated.
The paper is sent in the paper feeding direction and enters between the paper separation roller 3 and the paper separation pad 11, and as the paper separation roller 3 rotates, it rests on the lower guide plate 2a and is connected to the roller element 14 of the registration roller 16. Proceed towards the contact area with 15.

At this time, if multiple sheets of paper overlap and enter between the paper separation pad 11 and the paper separation pad 11, the frictional resistance between the sheets and the frictional resistance between the paper and the paper separation pad 11 will be reduced. Due to the difference, only the sheet on the side of the paper separation roller 3, ie, the upper side, is subsequently fed towards the registration roller 16.

When the leading edge of the paper P reaches the contact portion between the roller elements 14 and 15 of the registration roller 16, the leading edge of the paper P cannot advance any further because the roller element 14 is not yet rotated and is stopped. In response to this, the paper sorting row 53 continues to move in FIG. ! As the paper P is rotated in the direction of
While being guided by the curved portion 12a of No. 2, a slack curve C that bulges upward in the figure is generated. When this slack curve C increases to a predetermined amount, the hole 12b of the upper guide plate 12 is closed by the paper P in this slack curve portion. Then, this is immediately detected by the paper sensor 18, and the electromagnetic clutch 6 is immediately released. This allows paper 1
) The rotational drive of the roller 3 in the counterclockwise direction as viewed in FIG. 1 is stopped. In this way, when the slack curvature C of the paper P between the paper separation roller 3 and the registration roller 16 reaches a predetermined size, the rotational drive of the paper separation roller 3 is immediately stopped, thereby reducing the slack curvature C. Excessive increase in size is avoided, and the leading edge of the paper P reaches the registration roller 16.
The roller elements 14 and 15 are prevented from coming out from the contact area.

The paper sensor 18 for detecting that the slack curvature C of the paper P has reached a predetermined value is not only a reflective photoelectric type but also a contact type using a microphone switch 19 as shown in FIG. In this case, microphone 1]
It is sufficient that the contact piece 20, which is the actuator of the switch 19, protrudes into the paper path 13 from the hole 12b of the upper guide plate 12, and when the slack curvature C of the paper P reaches a predetermined size, the contact piece 20 is attached to the paper P. 21 is pressed, the contact of one microswitch is switched, and thereby it is detected that the slack curvature C of one sheet has reached a predetermined value.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited thereto.
It will be apparent to those skilled in the art that various embodiments are possible within the scope of the invention.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical sectional view showing one embodiment of the paper feeding device according to the present invention, FIG. 2 is a plan view of the paper feeding device according to the present invention shown in FIG. FIG. 7 is a schematic vertical cross-sectional view showing another embodiment of the paper feeding device. DESCRIPTION OF SYMBOLS 1...Paper feed stand, 2...Front punch, 3...Paper sorting roller, 4...Support shaft, 5...Side plate, 6...Electromagnetic clutch. 7... Transmission belt, 8... Paper sorting pad holder, 9
...Bracket, 10...Compression coil spring, 11.
...Paper sorting pad, 12...Upper guide plate, 13...
transportation passage. 14.15... Roller element, 16... Registration roller. 17...Bracket, 18...Paper sensor, 19.
...Micro switch, 20...Contact piece, 25...
Plate cylinder, 26...press roller

Claims (1)

[Claims] A plurality of sheets of paper placed on a paper feed table are taken out one by one by a paper sorting roller that is selectively driven to rotate and conveyed to registration rollers, and the registration rollers process the sheets for image formation at a predetermined time. a detection means for detecting that a predetermined amount of slack and curvature has occurred in the paper between the paper separation roller and the registration roller in the paper feeding device for conveying the paper to the section;
and a rotation stop means for stopping rotation of the paper separation roller based on detection by the detection means.