JPH05116783A - Paper sheet feeding device - Google Patents

Abstract

PURPOSE:To ravel out a problem of a paper sheet miss-feed at a paper sheet feeding paper, double feed, and jamming to improve reliability by stopping the feed of a paper sheet by a paper sheet feeding part through an air suction system at a proper timing. CONSTITUTION:A paper sheet feeding device comprises a paper sheet feeding part 1 to feed paper sheets 7 in a tray one by one through section by running a paper sheet feed belt 3 as suction is effected by means of air, and a conveyance roller 2 arranged right after the paper sheet feeding part 1 and arranged such that a distance x1 between a paper sheet holding line in which the paper sheet is held and the end line after suction of the paper sheet feed belt 3 of the paper sheet feeding paper 1 is reduced to a value lower than a minimum paper sheet feed size.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a copying machine, a printing machine, etc., and uses an air feeding system to remove paper in a tray.
The present invention relates to a sheet supply device that supplies sheets one by one.

[0002]

2. Description of the Related Art Conventionally, in a copying machine for recording an image on plain paper by electrophotography, a method of forming an image with toner on an image carrier and then transferring it onto plain paper is often used. The toner image corresponding to the latent image formed on the photosensitive drum by the reflected light from the original is transferred onto the paper supplied from the paper feed tray and then heated, so that the toner image can be fixed on the paper.

An air feeding method is often used to feed the sheets contained in the sheet feeding tray one by one. FIG. 2 is a schematic diagram of the paper feed system of the electronic copying machine. A sheet feeding unit 1 for running an endless sheet feeding belt 3 mounted between a pair of belt rollers 4A, 4B provided at a predetermined interval across a suction air flow passage, and a sheet feeding unit 1 A sheet feeding system is provided immediately after the sheet feeding unit 1 and holds a sheet 7 fed by the sheet feeding unit 1 and a conveying roller 2 including a pair of nip rollers for conveying the sheet 7 to the photosensitive drum unit. The sheet feeding belt 3 is a breathable belt, and suction air generated by opening the suction valve solenoid 5 that interlocks when sheet feeding is required passes through the sheet feeding belt 3 from below to above. As a result, the sheets 7 in the tray arranged below the sheet feeding unit 1 are sucked one by one to the sheet feeding belt 3 and sent to the side of the transport roller 2.

In the conventional air-feeding type paper feeding apparatus, the inter-roller distance x1 between the suction trailing edge line which is the suction working end of the belt roller 4A on the trailing end side and the paper holding line of the conveying roller 2 is It is usually set based on the equipment layout of the entire copier, and is not directly related to the paper length.
Demagnetization of suction valve solenoid 5 and belt roller 4A,
The 4B stop means that the timer is operated at a timing. FIG. 5 is a flow chart for explaining the operation control of the conventional paper feed system. When the sheet feeding start OK is checked in step n1, the process proceeds to step n2, and the suction valve solenoid (VVS1) 5 is excited (opened) and the timer T is set.
Counting is started.

The timer T is set to a first timing t1 from when the suction valve solenoid 5 is opened to when the suction action is exerted and a second timing t2 when the sheet feeding is stopped. When the process moves from step n2 to step n3 and reaches the end where the first timing t1 elapses in the process of timing, the process moves to the next step n4 and the belt roller (R1)
4A and the conveyance roller (R2) 2 are rotationally driven and the second timing t2 is measured. When the time progresses and moves to step n5 to reach the end of the second timing t2, the process moves to the next step n6 to stop the belt roller (R1) 4A and demagnetize the suction valve solenoid (VVS1) 5 (close the valve. ) Is performed, and a series of timing operations ends.

[0006]

Conventionally, the inter-roller distance x1 between the suction trailing edge line of the belt roller 4A and the sheet holding line of the conveying roller 2 is smaller than the minimum sheet size among the sheets of each size to be used. Since the leading edge of the sheet 7 reaches the transport roller 2, the next trailing sheet is sucked at the trailing edge line portion of the belt roller 4A at the time when the leading edge of the sheet 7 reaches the transport roller 2 and the sheet is fed. There is a problem that jamming (JAM) occurs.

In order to solve this problem, as shown in FIG. 2, a paper edge detector 6 is installed at a position immediately after the delivery side of the conveying roller 2 to detect the paper leading edge. It has been proposed in part to stop the belt roller 4A and demagnetize the suction valve solenoid 5 by the output of the above. However, the roller sensor distance x2 between the suction trailing edge line and the sheet edge portion detector 6 is increased. If it is long, depending on the paper size, it will be fed in the same way and double feed
There is a problem of becoming AM.

An object of the present invention is to provide a structure for precisely performing the timing of stopping the sheet feeding by air suction in the sheet feeding section, so that a sheet feeding error in the sheet feeding section or a double feed JAM
SUMMARY OF THE INVENTION It is an object of the present invention to provide a paper feeding device that can solve the above problems and can improve reliability.

[0009]

SUMMARY OF THE INVENTION According to the present invention, there is provided a paper feed unit for running a paper feed belt across a flow path of suction air to suck and feed each sheet in a tray, and a paper feed unit. In order to hold and convey the paper fed by this unit, the distance between the paper holding line and the suction trailing edge of the paper feeding belt of the paper feeding unit should be smaller than the minimum paper feeding size. And a conveying roller provided immediately after the sheet feeding device.

Further, according to the present invention, the paper feeding belt is traversed in the flow path of the suctioned air, and the paper feeding portion for sucking and feeding the sheets in the tray one by one, and the paper feeding portion for feeding. In order to hold and convey the paper, a conveyance roller provided immediately after the paper feed unit, a paper edge detector provided at a position immediately downstream of the conveyance roller to detect the leading edge of the incoming paper, and the conveyance roller A sheet feeding device including a sheet feeding unit stopping unit that stops the suction operation and the belt running operation of the sheet feeding unit according to the output generated by the sheet edge detector detecting the leading edge of the sheet during operation. Is.

Further, according to the present invention, the paper feeding belt is traversed in the flow path of the suctioned air, and the paper feeding portion for sucking and feeding the sheets in the tray one by one, and the paper feeding portion for feeding. Provided immediately after the paper feed unit so that the distance between the paper holding line and the suction trailing end line of the paper feed belt of the paper feed unit is smaller than the minimum paper feed size in order to hold and convey the paper In order to detect the transport roller and the leading edge of the incoming paper, make sure that the distance between the detection point and the suction trailing edge of the paper feed section is smaller than the minimum paper feed size. The paper edge detector installed in the printer and the output generated when the paper edge detector detects the leading edge of the paper during the operation of the transport rollers stop the suction operation and belt running operation of the paper feeding section. And a sheet feeding device.

[0012]

According to the present invention, the conveying roller is arranged immediately after the paper feeding section so that the distance between the sheet holding line of the conveying roller and the suction rear end line of the sheet feeding belt becomes smaller than the minimum sheet feeding size. Since it is provided, when the paper reaches the transport roller and is held, the paper will always have a portion of the paper that has not reached the suction portion of the paper feed unit on the trailing edge side. When automatically stopping the paper feeding by suction, the on-operation time of the timer is shortened as much as possible and automatically stopped when the leading edge of the paper reaches the conveyance roller, so that the next paper is not fed. it can.

Further, according to the present invention, a sheet edge detector is provided at a position immediately downstream of the conveying roller so that the suction operation and the belt running operation of the sheet feeding section are operated by receiving the output of the detector. Since the paper is stopped by the paper stopping means, the paper feeding is stopped while the paper is securely held by the conveying rollers, so that the paper jam does not occur due to the paper feeding failure, and the trouble of stacking and feeding is also prevented. It can be prevented.

According to the present invention, the distance between the sheet holding line of the transport roller and the detection point of the sheet edge detector is smaller than the minimum sheet feed size with respect to the suction trailing edge of the sheet feeding belt. Since the output of this detector is used to stop the paper feed, paper jam occurs when the paper feed stops until the paper is held by the conveyance roller, and when the paper is a small size, the next paper is sucked. It is possible to reliably avoid any double-feed clogging that occurs as a result.

[0015]

1 shows a schematic structure of an electronic copying machine according to an embodiment of the present invention. Document 1 placed on a transparent platen 9
0 is emitted by the light from the light source 11. Light source 11
Is movable in the left-right direction on the paper surface of FIG. 1, and illuminates the entire document 10 while moving from right to left. The reflected light from the original 10 is reflected by the movable mirror 12 and the fixed mirror 13 by changing its direction, and is guided to the exposure point 14A on the photosensitive drum 14 which rotates around the axis.

A charge unit for charging the photosensitive drum 14 is provided upstream of the exposure point 14A. The photoconductor drum 14 includes a photoconductive material such as selenium (Se), has a good electric insulation property in a dark place, and holds the electric charge given by the charge unit 15. When light is irradiated at the exposure point 14A, the electric resistance decreases and the surface charge is dissipated. A blank lamp unit 16 is provided downstream of the exposure point 14A. The blank lamp unit 13 is provided to remove unnecessary charges from the photosensitive drum 14 and form a void lamp during copying. A developing tank 17 for supplying black toner is provided on the downstream side of the blank lamp unit 13. The electrostatic latent image formed on the exposure point 14A is visualized by the toner supplied from the developing tank 17.

A sheet feeding section 18 is provided on the downstream side of the developing tank 17. For this paper feeding section 18,
First tray 19, second tray 20 and third tray 21
The paper 7 accommodated in the paper is selectively supplied. One sheet of paper 7 sent out from one of the trays is guided between the photosensitive drum 14 and the pressure roller, and the toner image is transferred. The sheet 7 to which the toner image is transferred is guided to the fixing device 22 and is fixed by heating and pressing the toner on the sheet surface.

The trays 19 to 21 have the same structure and are accommodated in the cassette chamber below the copying machine main body for B5, A4 and B4 depending on the size of the paper 7. FIG. 2 shows the structure of the paper feed system of each tray. The structure of each part has been described in detail in the section of the prior art, and therefore its explanation is omitted and the conveyance roller 2 and the paper edge detector 6 are described. The arrangement will be described.

The carrying roller 2 is provided on the downstream side of the belt roller 4B. The conveyance roller is positioned such that the distance x1 between the nip point, which is the sheet holding line of the conveyance roller 2, and the suction trailing end line of the sheet feeding belt 3, which is the axially lower portion of the belt roller 4A, is smaller than the minimum sheet feed size. Two are provided. On the other hand, the paper edge detector 6 is provided at a position immediately downstream of the transport roller 2. The paper edge detector 6 is provided so that the distance x2 between the detection point of the detector 6 and the suction trailing edge line is smaller than the minimum paper feed size.

FIG. 3 shows an electrical configuration for controlling the electronic copying machine shown in FIG. The microcomputer 30, which is a central part of the operation control, controls according to a control program stored in the ROM 31 in advance. RAM32
Is used as a buffer memory, a flag and other calculation areas required for copy control. Signal input device 3
Signals input by the key switch 5, copy paper switch, paper edge detector 6, etc. are transferred to the microcomputer 30 via the interface circuit 33. That is, in the main body of the copying machine, the detection signal of the sheet conveyance position, the detection signal of the position of the photosensitive drum 14 and the like are transmitted via the interface circuit 33 to the microcomputer 3
Sent to 0. The control signal from the microcomputer 30 is transferred to the driver array 36 via the interface circuit 34, and the driver array 36 controls the display of the copy magnification, the display of other display circuits, and the load control of the main body of the copying machine.

FIG. 4 is a flow chart showing the operation of the start / stop control of the paper feed system. When the sheet feeding start OK is selected in step m1, the process proceeds to step m2, and the preliminary operation for sheet feeding is started. The start of the preliminary operation is the first timing corresponding to the excitation (opening) of the suction valve solenoid (VVS1) 5, the start of timing of the timer T37 incorporated in the microcomputer 30 and the rising time until the suction action is reliably performed. and the setting of t1. As a result, the sheet is not fed until suction is possible. When the count-up of the timer T37 is selected in step m3, the process proceeds to the next step m4 and the paper feeding operation is started. The paper feeding operation is started by rotating the belt roller (R1) 4A and the transport roller (R2) 2. As a result, the uppermost one sheet 7 in the tray is fed by the traveling accompanied by the suction of the sheet feeding belt 3, and the conveying roller 2
The sheet is further held by and is sent to the sheet feeding section 18 side.

When the arrival of the leading edge of the sheet 7 is detected by the sheet edge detector 6 in step m5, the process proceeds to step m6 and a stop output is output to the sheet feeding section stopping means to output the valve solenoid (VVS1) 5. Demagnetization (valve closing) and stop of the belt roller (R1) 4A are performed. As a result, the traveling with suction is stopped and the sheet feeding is stopped. At the time of stopping the feeding in step m6, the trailing edge of the sheet that has been sucked has not reached the trailing edge of the suction of the sheet feeding belt 3.
The next sheet is not sucked by mistake, and since the leading edge of the sheet is held by the transport roller 2 at this time, the transport is reliably performed.

Instead of the embodiment described above, the distance (x between the paper holding line of the conveying roller 2 and the suction trailing end line of the paper feeding belt (x
To make 1) smaller than the minimum paper feed size,
A structure in which the carrying roller 2 is arranged and suction traveling is stopped at a timer set time.
It is possible to prevent the JAM of the paper even if the paper edge detector 6 is provided immediately after the downstream side of the paper and the structure in which the suction traveling is stopped by the detection output is adopted. Also included in the present invention.

[0024]

As described above, according to the present invention, by arranging the conveying roller so that the distance between the sheet holding line of the conveying roller and the suction rear end line of the sheet feeding belt is smaller than the minimum sheet feeding size. Further, it is possible to reduce the time required for the paper feed belt to travel with air suction, and prevent paper jams due to being fed. In addition, a paper edge detector is provided immediately downstream of the conveying roller, and the output is used to stop and control the traveling of the paper feeding belt accompanied by air suction, so that the paper is securely held on the conveying roller. A paper feeding failure does not occur, and the next paper will not be double-fed. Further, the detector is arranged so that the distance between the detection point of the paper edge detector and the suction trailing edge of the paper feed belt is smaller than the minimum paper feed size, and this output causes the paper feed belt accompanied by air suction. It is possible to avoid the paper jam due to the inability to convey the paper and the double-feed jam for sucking the next paper by configuring the stop control of the traveling.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic configuration of an electronic copying machine according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a configuration of a paper feeding system of the electronic copying machine shown in FIG.

FIG. 3 is a block diagram showing an electrical configuration for control of the embodiment shown in FIG.

FIG. 4 is a flowchart showing an operation for controlling start / stop of a paper feed system in the embodiment shown in FIG.

FIG. 5 is a flowchart showing an operation for controlling start / stop of a conventional paper supply device.

[Explanation of symbols]

 1 Paper Feeding Section 2 Conveying Roller 3 Paper Feeding Belt 4A, 4B Belt Roller 5 Suction Valve Solenoid 6 Paper Edge Detector 7 Paper 19 Tray 37 Timer

Claims (3)

[Claims] 1. A paper feed unit that runs a paper feed belt across a flow path of suction air to suck and feed each of the sheets in a tray, and holds the paper fed by the paper feed unit. In order to convey the paper, the paper holding line and the conveyance roller provided immediately after the paper feeding unit are arranged so that the distance between the paper holding line and the suction rear end line of the paper feeding belt of the paper feeding unit is smaller than the minimum paper feeding size. A sheet feeding device comprising: 2. A paper feed unit that runs a paper feed belt across a flow path of suction air to suck and feed each of the sheets in the tray, and holds the paper fed by the paper feed unit. For transporting the paper, the transport roller is provided immediately after the paper feed section, the paper edge detector that is provided immediately downstream of the transport roller to detect the leading edge of the incoming paper, and the transport roller is in operation. A sheet feeding device, comprising: a sheet feeding unit stopping unit that stops the suction operation and the belt running operation of the sheet feeding unit according to an output generated by detecting the leading edge of the sheet by the sheet edge detector. 3. A paper feed unit that runs a paper feed belt across a flow path of suction air to suck and feed each of the sheets in the tray, and holds the paper fed by the paper feed unit. In order to convey the paper, the paper holding line and the conveyance roller provided immediately after the paper feeding unit are arranged so that the distance between the paper holding line and the suction rear end line of the paper feeding belt of the paper feeding unit is smaller than the minimum paper feeding size. In order to detect the leading edge of the incoming paper, the distance between the detection point and the suction trailing edge of the paper feed section should be set smaller than the minimum paper feed size at a position immediately downstream of the transport roller. The paper edge detector and the paper feed section stopping means that stops the suction operation and belt running operation of the paper feed section by the output generated when the paper edge detector detects the leading edge of the paper while the transport roller is operating. A sheet feeding device including: