JPS6151428A - Control method for friction separated paper feed - Google Patents

Abstract

PURPOSE:To shorten the intervals of paper feed by correcting re-feeding time on the basis of actual conveyance velocity at which a paper sheet is supplied from paper feeding part to preliminary paper feeding position, and further by correcting the re-feeding time of a succeeding paper sheet on the basis of actual conveyance velocity for re-feeding. CONSTITUTION:When a paper feeding signal is given, a feed roller 2a and a pickup roller 1 are made to rotate, and the uppermost paper sheet in a paper sheet stack is made to pass a sensor S1 and conveyed until it is detected by a sensor S2. In this instance, conveyance velocity from sensor 1 to sensor 2 is calculated by an operation control means 10 and the aforementioned re-feeding time is corrected in reference to the distance of conveyance at this conveyance velocity. Also, the conveyance velocity of paper between sensors S2 and S3 is calculated at the time of the said re-feeding for the correction of the re-feeding of a succeeding paper sheet. For the third and its succeeding paper sheets, data obtained with the preceding paper sheet is updated in regular succession and calculated.

Description

Detailed Description of the Invention (Technical Field) The present invention uses a friction separation paper feeding system, in which a feed roller and a separating member (a fixed pad, a roller, or a reversing roller via a torque limiter, etc.) are brought into pressure contact with each other. The present invention relates to a method for controlling paper feeding at small paper intervals in a paper feeding system using a pair of separation rollers to separate double fed paper.

(Prior art) Normally, the number of copies per copy is determined by the linear speed and spacing (because the size is fixed), so in high-speed copying machines, +1! Efforts have been made to increase the speed (paper conveyance speed by rollers) and shorten the paper passing interval.

For friction separation paper feeding (fixed retard type), a method is known in which multiple sensors are arranged and the paper feeding interval is controlled by the sum of the sensor detection time and the set time. , the influence of size, roller changes over time, environmental changes, etc. is not constant, and the influence of these changes is extremely large, so it is assumed that the linear speed is constant throughout the conveyance path. Conventional control methods have not been able to make the paper spacing sufficiently small.

Alternatively, if the paper size was set to small, a problem occurred in which the next paper overlapped with the previous paper.

(Objective) It is an object of the present invention to provide a control method that eliminates the second drawback of the conventional example and achieves small paper spacing in frictional separation paper feeding.

(Structure) For this purpose, the present invention feeds the paper fed out from the paper feeding unit to the preliminary paper feeding position and temporarily stops it, detects the actual conveying speed at the time of refeeding the paper, and The present invention is characterized in that the scheduled re-feeding time of the paper stopped at the subsequent preliminary paper-feeding position is corrected.

Hereinafter, five embodiments of the present invention will be described based on the drawings.

FIG. 1 is a schematic layout diagram of a paper feeding device according to the present invention, FIG. 2 is a functional block diagram according to an embodiment, and FIGS. 3(a) and (h) are flowcharts of its operation.

In FIG. 1, 1 is a pickup roller that sends out the paper, 2 is a pair of friction separation rollers (consisting of a feed roller 2a and a separate roller 2b), 3 is a grip roller, and 4 is a grip roller.
is a registration roller, S□, Sz, and Sg are reflective sensors, St, S:= is between the friction separation roller pair 2 and the grip roller 3, and S:I is between the grip roller 3 and the registration roller 4. It is arranged.

In addition, W shown in the figure is the paper leading edge position variation range, and Ql is the first speed (linear speed) Vx (Vx
p) Measurement distance, P is paper refeeding position, Q2 is V1p after paper refeeding
The distance Q3 is conveyed at the (actual linear velocity) is the distance measured by the grip roller 3 at the second velocity (linear velocity) V=(V=p).

In Fig. 2, 5 is a solenoid for driving the pickup roller, and 6 is a motor (F) for driving the feed roller 2a.
M), 7 is the registration roller 4@motor (RM)
It is. These drive systems and sensors Sl, S2. S:l is connected to the driving means 8, and input signals are taken into the arithmetic control means 10 via the signal input/output means 9.

11 is a control program storage means, 2 is a signal input/output means, and 13 is an input section for inputting paper size, etc.

The paper must be sent to the image forming area at a predetermined timing, which can be determined from the required timing of L/registration roller start time (at this time, roller rotation error, roller rotation start-up delay time).

Paper following delay time, etc. are taken into account9).

Therefore, the paper feeding start time can be scheduled in advance based on the distance between the paper feeding section and the registration rollers. Hereinafter, the operation will be explained sequentially starting from the first paper.

The first paper feed signal is given with a margin from the first paper registration start time, including variations in speed, waiting time, etc. in the conveyance path. Now that the paper feed signal has been learned, the feed roller 2a and the pickup roller l are both rotationally driven.
It passes through sensor S1.

Convey the paper until the sensor S2 detects the paper. sensor S
When paper is detected at step 1, the pickup roller 1 is released from rotation by a solenoid 5. Also, the sensor S2 detection time is measured from the paper detection time in the sensor S1, and the sensor S1.
Since the distance 111t 11 :L between St is fixed, the conveyance speed therebetween can be calculated. To refeed the first paper, the distance c from the sensor S2 to the grip roller 3 is
Considering the paper stop delay error as a correction value) Q2 is conveyed at the feed roller conveyance speed first speed V1p measured above, and the paper is conveyed from the grip roller 4 to the registration roller 5 at the planned conveyance speed, Furthermore, considering the distance required for the paper to be aligned with the registration roller 5, the sum of these times is required, so this time is subtracted from the registration roller start time (corrected) and the paper refeed signal is calculated. given as.

In friction separation, you have to be prepared for variations in the linear conveyance speed of the feed roller section of several tens of percent;
It is possible to hold the

The re-fed first paper is sent to the grip roller 3 at the feed section speed, and thereafter is sent at the grip roller section speed (second speed V2 p) until registration alignment. In the embodiment, the paper leading edge detection time by the third sensor S3, the paper refeeding time, the second sensor S2, the grip roller 3, and the sensor S3
The grip roller conveyance speed is calculated based on the position.

However, as another option, one sensor may be added after the grip roller, and the speed may be calculated between that sensor and a third sensor. After the first paper is aligned with the registration rollers 4, it is conveyed by the registration rollers 4 at a predetermined time and sent to the image transfer area.

The second paper is given by calculating a paper feeding time at which the trailing edge of the first paper does not overlap with the leading edge of the second paper, based on the paper refeeding time, the feeding unit, the grip roller unit linear velocity, and the paper size. Preliminary paper feeding is performed in the same way as for the first paper, and the paper refeed time is set to the grip roller speed as the planned value for the first paper, but for the second paper,
Calculated based on paper transport speed. Thereafter, preliminary paper feeding and refeeding are repeated sequentially based on the previous paper information.

Note that although the description refers to sensor detection, a certain reading time is usually set in the circuit for stability of data capture in sensor detection. These numerical values are omitted to complicate the explanation.

Also, depending on the length of the conveyance path, there may be cases where information from the paper before the previous paper is used instead of information about the previous paper, information from the paper before the previous paper is used instead of information about every certain number of sheets, or information about the paper after every certain number of sheets. You may update.

Although no particular mention is made of the wAl'II source, it seems possible to use it because it can be easily controlled by a pulse motor.

Next, the above-mentioned first paper refeed time 1st 1. The grip roller conveyance linear velocity V3PI, second paper feeding time tfz, and second paper refeeding time tr1.1 will be described.

tl-11=tg+ (mu, every Js) -6, (
1) V+ Vl tRi; 1st paper 1 noji start time a4; distance between grip roller and registration roller QB;
Necessary distance for paper alignment■,! 1 Grip roller scheduled conveyance linear speed V1p: Measured linear speed of feed roller part 1p Paper feeding direction length ls; Distance between foot rollers and grips To; Margin time (determined by taking into account assumed errors) 12... ( 1)
In the formula, ■ヱ→V2P. (4) Figure 3 is a flowchart showing the control operation described above, and (a
) indicates the first column, and (b) indicates the second column.

Note that for the third and subsequent sheets, the data obtained for the previous sheet is sequentially updated and calculated in the same way as for the second sheet.

The arithmetic processing of each nut in the flowchart shown in FIG. 3 is performed by the arithmetic control means 10 shown in FIG. 2, and reading and writing of various data is performed by the control program storage means 11. Then, according to this calculation result, solenoid 5. The motor 6.7 is driven via drive means 8.

(Effects) The present invention is as described above, and according to this method, it is possible to absorb paper leading edge position variations peculiar to the frictional separation method, and to eliminate mechanical differences, paper differences, environmental changes over time, etc. (including initial position irregularities). This makes it possible to compensate for variations in conveyance speed. Therefore, the intervals that must be taken due to these variations can be eliminated,
Paper spacing can be set smaller.

Therefore, by processing a high number of sheets at a low linear speed, the quality of the image forming system is improved, and it is possible to obtain great effects such as an increase in machine life.

[Brief explanation of drawings]

FIG. 1 is a schematic layout diagram of a paper feeding device according to the present invention;
Figure 2 is a functional block diagram according to one embodiment of the same, and Figure 3 (
a) and (b) are flowcharts of the operation.

Claims (1)

[Claims] On the downstream side of the paper feed section, there is a pair of friction decomposition rollers, a grip roller,
Registration rollers are sequentially provided, a first sensor and a second sensor are sequentially provided between the friction-resolving roller pair and the grip roller, a second sensor is further provided between the grip roller and the registration roller, and the paper feed signal is used to detect the second sensor. The first sensor placed in front of the preliminary paper feed and this second sensor
The first paper transport speed during this period is calculated from the difference in the distance between the sensors and the arrival time, the scheduled paper re-feeding time is corrected by the distance to be transported at this first speed, the paper is re-fed, and then the third The second speed is calculated based on the distance between the sensor and the second sensor and the substantial elapsed time between them, and the re-feed time of the next paper feed is corrected based on this second paper conveyance speed. Features a frictional separation paper feeding control method.