JPH07196235A - Machine glazed paper end detector - Google Patents

Abstract

PURPOSE:To provide a machine glazed paper end detector, in which design and assembly are facilitated and costs can be reduced, by shortening the length of a rotary shaft of a driven roller constituting a part of the machine glazed paper end detector. CONSTITUTION:A feeding roller 5 and a driven roller 6, which is brought into contact with the feeding roller 5 via paper so as to be frictionally driven, are arranged as paper feeding means feeding machine glazed paper 1 to an image forming unit 4. The rotary shaft 13 of the driven roller 6 is formed into short length one and is supported by a guide plate 10 rotationally, while an encoder 15 detecting the terminal end of the machine glazed paper 1 is brought into contact with the surface of the driven roller 6 and is supported rotationally.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feed device for feeding a roll paper used in an image forming apparatus such as a copying machine or a printer to an image forming section, and a roll for detecting the absence of paper, that is, the end of the roll paper. The present invention relates to a paper end detection device.

[0002]

2. Description of the Related Art As a means for feeding a roll paper to an image forming section, there is known a roller means comprising a feed roller having a driving means and a driven roller which is frictionally driven by contacting the feed roller via the paper. The leading end side of the roll paper pulled out between these rollers is sandwiched and sent to the image forming unit. These rollers are rotatably supported via bearings by providing shaft holes on both side plates of the apparatus main body so as to be parallel to the width direction of the roll paper. Similarly to the feed roller, the rotation shaft of the driven roller is supported by both side plates of the main body of the apparatus, and an encoder that detects the end of the roll paper is fixed to the shaft end protruding outward of the side plate. The end of the roll paper is detected by monitoring the presence / absence of rotation of the encoder at the time of paper feeding by a sensor arranged facing the encoder.

[0003]

In the above-mentioned apparatus, particularly when handling a wide and large size roll paper of A2 or more, due to a design or strength problem, the rotation used as the shaft portion of the feed roller and the driven roller. It is necessary to make the diameter of the shaft thick so that it does not bend under its own weight. Also,
Since the encoder is fixed to the shaft center of one end of the rotation shaft of the driven roller that protrudes to the outside of the side plate of the device body, this is an obstacle to downsizing and cost reduction of the device. further,
In the assembling work, the two rotating shafts of the feed roller and the driven roller must be simultaneously incorporated on both side surfaces, which complicates the assembling work.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a roll paper end detection device which is easy to design and assemble and which can be manufactured at low cost.

[0005]

In order to solve the above-mentioned problems, a roll paper whose end is fixed to a winding core according to the present invention,
A roll that is fed by a feed roller that is driven during paper feeding and a driven roller that is pressed against the surface of the feed roller via paper and that is driven by frictional transmission, and that detects the rotation of the driven roller and detects the end of the roll paper. In the paper end detection device, the driven roller is a short-length roller that is axially supported in the space between both side plates that support the shaft of the feed roller, and contacts the surface of the driven roller to be driven. An encoder is provided, and the end of the roll paper is detected based on the signal from the encoder.

[0006]

In this structure, the driven roller, which is rotatably arranged in the space between the side plates, sandwiches the roll paper and sends it out as the feed roller rotates. When the roll paper is consumed and ended, the end of the roll paper is fixed to the winding core, so the roll paper stops and the feed roller slides on the roll paper. The rotation of the driven roller stops due to the stop of the roll paper, and the encoder that is rotating by contacting the driven roller also stops. As described above, when the encoder is stopped during paper feeding, that is, when the feed roller is rotating, the signal is detected to notify the end of the roll paper.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side sectional view showing a state in which a roll paper end detection device according to the present invention is incorporated in an image forming apparatus main body. Reference numeral 1 is a roll paper as a transfer material, and a detachable holder (not shown) is inserted into a cylindrical core member 2 around which the roll paper 1 is wound, and the holder is supported by an appropriate mounting portion. By doing so, the roll paper is rotatably loaded inside the image forming apparatus. The roll paper 1 has its end fixed to the core 2 with an adhesive or the like,
Although divided into two types, that is, not fixed, the present invention is preferably used for those in which the end of the roll paper 1 is bonded to the core 2.

A roll paper end detection device 3 is arranged above the position where the roll paper 1 is loaded. The roll paper end detection device 3 rotates based on a paper feed signal and feeds the roll paper 1 to the image forming unit 4, and a feed roller 5.
The driven roller 6 that is pressed against the feed roller via the pulled-out roll paper and is driven by the frictional force, and the driven roller 6
An encoder 7 that contacts the surface of the roller and rotates following a driven roller, and a sensor 8 that detects a signal from the encoder 7.
And guide plates 10 and 11 for guiding the roll paper 1 wound around the winding core 2 to the cutter 9. Feed roller 5
The driven roller 6 includes a rotary shaft 12 such as a metal shaft,
13 and elastic rollers 14, 15 made of rubber, synthetic resin, or the like having a relatively large frictional resistance, which are fixed to substantially central portions of the rotary shafts 12, 13 in the axial direction. The elastic rollers 14 and 15 are
The roll paper passing between them is formed in a cylindrical shape or a barrel shape so as not to be wrinkled, and the roll paper 1 is sent out by contacting it with an appropriate pressure. Further, these rollers may be rollers having a short length so as to come into contact with a part of the center of the width of the roll paper. The feed roller 5 is rotatably supported at both ends of the rotary shaft 12 by both side plates 35 of the apparatus main body by bearings 36, 37 and the like. An external drive source is connected to one end of the feed roller 5 by a gear, a belt or the like to synchronize with the rotation speed of the photoconductor 20. Driven roller 6
Is arranged in the space between the side plates 35,
A rotary shaft 13 that is thinner than the rotary shaft 12 of the feed roller 5 is rotatably supported by a blanket (not shown) provided on the guide plate 10 via bearings 38 and 39. Abuts the surface of. The guide plates 10 and 11 include elastic rollers 14,
A hole is formed to such an extent that it does not hinder the contact of 15 with each other, and the surface used for the opening is bent perpendicularly to the surface of the guide plate 10 so that the rotary shaft 13 of the driven roller 6 and the rotary shaft of the encoder 7 are formed. Also serves as a side plate that rotatably supports. As the sensor 8, a sensor utilizing an optical sensor such as a photo interrupter sensor is preferably used.

FIG. 2 is a diagram showing an example of an embodiment of the roll paper end detection device according to the present invention, and FIG. 3 is a diagram showing a conventional example. In the conventional example of FIG. 3, the rotary shafts 12, 13
Must be arranged longer than the width of the roll paper in order to be mounted between the side plates 35, and must be thickened to some extent in terms of strength such as bending of the rotary shafts 12 and 13. Further, it is necessary to further widen the decorative plate that covers the encoder 7 and the sensor 8 by arranging them outside the device side plate 35. In the embodiment shown in FIG. 2 as compared with the conventional example, the thickness of the rotary shaft can be made thinner by reducing the length of the rotary shaft 13 of the driven roller 6. Further, by arranging the encoder 7, the sensor 8 and the like inside the device, it is possible to make the device compact.

The operation will now be described with reference to FIG. 1. As is well known, in the image forming section 4, the surface of the photoreceptor 20 rotating in the direction of arrow A is corona charged by the corona discharger 21. Then, an optical image is projected from the original image projection device 22 to form an electrostatic latent image on the photoconductor 20. The latent image on the surface of the photoconductor 20 is visualized by the toner in the developing device 23 and sent to the transfer unit. On the other hand, the leading end of the roll paper 1 is sent to the transfer section of the image forming section 4 by the feed roller 5 and the driven roller 6. Next, the roll paper 1 cut into a desired size by the cutter 9 transfers the toner image on the photoconductor 20 by the transfer corona discharger 26 and the peeling corona discharger 27. After that, roll paper 1
The image is conveyed to the fixing device 28, made into a permanent image, and discharged outside the apparatus. The surface of the photoconductor 20 after the transfer is cleaned by a cleaner 29, and is gradually charged by an eraser lamp 30 to prepare for the next image formation.

When the roll paper 1 is consumed by the image formation and reaches the end, the roll paper is stopped because it is fixed to the core 2 despite the rotation of the feed roller 5.
At this time, the feed roller 5 rotates while slipping on the roll paper 1, but the driven roller 6 does not rotate because the roll paper 1 stops. When the driven roller 6 is stopped, the encoder 7 contacting the surface of the elastic roller 15 is stopped, and the sensor 8 detects this signal to notify the operator that the roll paper 1 needs to be replaced. INDUSTRIAL APPLICABILITY The present invention is preferably used for roll paper in which the roll paper 1 is fixed to the winding core 2, but in order to prevent malfunction when the roll paper 1 is not fixed to the winding core 2, FIG. Photo sensor 3 shown
1 may be arranged. The photo sensor 31 includes a sensor light transmitter and a light receiver, and the roll paper blocks the sensor light of the photo sensor. When the roll paper is exhausted, the light receiver of the photo sensor 31 detects the end of the roll paper. Let me know. By using these methods together, the end of the roll paper can be detected in both the roll paper whose end is fixed to the core or the roll paper which is not fixed to the core.

[0012]

According to the roll paper end detection device of the present invention, by shortening the rotation shaft of the driven roller, it is possible to reduce the thickness of the shaft without bending the rotation shaft. For this reason, it is possible to provide a roll paper end detection device that can be manufactured at low cost and can be easily assembled by miniaturizing parts.

[0013]

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment according to the present invention.

FIG. 2 is a plan view showing an embodiment according to the present invention.

FIG. 3 is a plan view showing a conventional example.

[Explanation of symbols]

 1 roll paper 2 core 5 feed roller 6 driven roller 7 encoder 8 photo interrupter

Claims (1)

[Claims] 1. A roll paper, the end of which is fixed to a winding core, is fed out by a feed roller driven at the time of feeding and a driven roller which is pressed against the surface of the feed roller via the paper and driven by friction transmission. In a roll paper end detection device that detects the end of the roll paper by detecting the presence or absence of rotation of the roller, the driven roller is of a short length that is axially supported in the space between both side plates that support the shaft of the feed roller. It consists of Laura,
A roll paper end detection device characterized in that an encoder is provided so as to come into contact with the surface of the driven roller and be driven, and the end of the roll paper is detected based on a signal from the encoder.