JPH0678131B2 - Friction separation paper feed control method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a friction separation sheet feeding method, that is, a friction roller and a separating member (a fixed pad, a roller, or a reversing roller via a tricrimitter) are pressure-contacted to each other to perform friction separation. The present invention relates to a small sheet interval paper feed control method in a paper feed method in which a pair of rollers is used and a multi-feed is handled.

(Prior Art) Normally, the number of copies is determined by the linear velocity and the interval (since the size is determined), so the processing capacity is determined. Therefore, in a high-speed copying machine, the linear velocity (paper conveying speed by rollers) up The intervals are being shortened.

A method is known in which a plurality of sensors are arranged in the friction separation paper feed (fixed retard type) and the paper feed interval is controlled by the sum of the sensor detection time and the set time. , Size, roller changes with time, environmental changes, etc. are not constant, and the degree of influence of such changes is extremely large. However, the paper spacing cannot be made sufficiently small with this control method.

If it is made smaller, there is a problem that the next sheet overlaps the previous sheet.

(Object) It is an object of the present invention to provide a control method for solving the above-mentioned drawbacks of the conventional example and achieving a small paper gap in friction separation paper feeding.

(Structure) Therefore, according to the present invention, the paper fed from the paper feeding unit is fed to the preliminary feeding position, temporarily stopped, and the actual transport speed at the time of re-feeding thereafter is detected, whereby The present invention is characterized in that the scheduled re-feeding time of the paper stopped at the pre-feeding position is corrected.

An embodiment of the present invention will be described below with reference to 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 one embodiment, and FIGS. 3 (a) and 3 (b) are flow charts of the operation. .

In FIG. 1, 1 is a pick-up roller that sends out a sheet, 2 is a friction separation roller pair (consisting of a feed roller 2a and a separate roller 2b), 3 is a grip roller, 4 is a registration roller, and S ₁ , S ₂ and S ₃ are reflections. Type sensor, S ₁ , S
₂ is between the friction separating roller pair 2 and the grip roller 3, and S ₃
Is disposed between the grip roller 3 and the registration roller 4.

Further, W shown in the figure is a paper tip position variation range, l ₁ is the first velocity (linear velocity) V ₁ (V ₁ p) measurement distance by the separation roller 2,
P is the re-feed position, l ₂ is the distance conveyed at V ₁ p (actual linear velocity) after re-feed, l ₃ is the second velocity (linear velocity) V ₂ (V ₂ p by the grip roller 3) ) Measured distance.

In FIG. 2, 5 is a solenoid for driving the pick-up roller, 6 is a motor (FM) for driving the feed roller 2a, 7
Is a motor (RM) for driving the registration roller 4. The drive system and the sensors S ₁ , S ₂ , S ₃ and the drive means 8 are connected to each other, and the input signal is taken into the arithmetic control means 10 via the signal input / output means 9. Reference numeral 11 is a control program storage unit, 12 is a signal input / output unit, and 13 is an input unit such as a paper size.

The sheet must be sent to the image forming area at a predetermined timing, and the registration roller start time can be determined from this required timing (at this time, roller nip error, roller rotation rising delay time, paper following delay time, etc. are taken into consideration. ).

Therefore, the paper feed start time can be scheduled in advance from the distance between the paper feed unit and the registration rollers. The operation will be sequentially described below from the first sheet.

The first paper feed signal is given with a certain margin from the first paper registration start time, including variations in speed in the transport path, waiting time, and the like. When the paper feed signal is given, both the feed roller 2a and the pick-up roller 1 are rotationally driven, pass through the sensor S _1, and are conveyed until the paper is detected by the sensor S ₂ . When the paper is detected by the sensor S ₁ , the pickup roller 1 is released from the rotation by the solenoid 5. Also sensor S ₁
Since the detection time of the sensor S ₂ is measured from the paper detection time in, and the distance l ₁ between the sensors S ₁ and S ₂ is fixed, the transport speed between them can be calculated. To re-feed the first paper, use the sensor
The distance from S ₂ to the grip roller 3 (considering the paper stop delay error as a correction value) l ₂ is conveyed at the measured feed roller conveyance speed first speed V ₁ p, and the registration roller 5 from the grip roller 4 is conveyed. It is assumed that the sheet is conveyed at a planned conveying speed up to, and the sum of these times is required in consideration of the distance required for the registration rollers 5 to align the paper. It is subtracted from the time (corrected) and given as a re-feeding signal.

The feed linear velocity of the feed roller part must be expected to fluctuate by several tens of percent in friction separation, but the transport linear velocity can be suppressed to several percent.

The re-fed first paper is sent to the grip roller 3 at the speed of the feed portion, and thereafter, is sent to the registration of the grip roller portion at the speed of the grip roller (second speed V ₂ p). Third in the example
According to the paper leading edge detection time by the sensor S ₃ , the re-feeding time, the second sensor S ₂ , the position of the grip roller 3 and the sensor S ₃ ,
Calculates the grip roller section transport speed. However, as another proposal, one sensor may be added after the grip roller and the speed may be calculated between the sensor and the third sensor. After being aligned with the registration roller 4, the first sheet is sent to the image transfer area conveyed by the registration roller 4 at a predetermined time.

The second sheet is given by calculating the sheet feeding time at which the trailing edge of the first sheet does not overlap with the leading edge of the second sheet, based on the sheet re-feeding time, the feeding portion, the grip roller portion linear velocity, and the sheet size. Preliminary sheet feeding is performed in the same manner as the first sheet, and at the sheet re-feeding time, the grip roller speed for the first sheet is set to a predetermined value, but for the second sheet, calculation is performed at the transport speed of the first sheet. After that, the pre-feeding and the re-feeding are repeated according to the previous sheet information.

It should be noted that although the term “sensor detection” is used in the description, a fixed reading time is set on the circuit for the stability of normal data acquisition in the sensor detection. These numbers are omitted because the explanation is complicated.

Also, depending on the length of the transport path, if the information of the previous sheet is used instead of the information of the previous sheet, or if the information of the previous sheet is used instead of the information for every certain number of sheets, or the information for every certain number of sheets is used. May be updated.

Although no particular reference is made to the drive source, it seems that it can be used because the control by the pulse motor is easy.

Next, the above-mentioned first paper refeed time t _M1 , grip roller conveyance linear velocity ₂ p, second paper feed time tf ₂ , second paper refeed time t _M2
I will describe.

t _M1 = t _R1 − {l ₂ / V ₁ p ＋ (l ₄ ＋1 _B ) / V ₂ } …… (1) t _R1 ; 1st paper registration time l ₄ ; Grip roller-registration roller distance l _B ; Required paper alignment distance V ₁ p; Measured linear velocity of feed roller V ₂ ; Planned linear velocity of grip roller transport V ₂ p = (l ₃ −l ₂ ) / (t ₃ −l ₂ / V ₁ p) …… (2 ) T ₃ ; Third sensor detection time tf ₂ = l ₂ / V ₁ p (lp-l ₅ ) / V ₂ + To ...... (3) lp; Paper feed direction length l ₅ ; Distance between feed roller and grip roller To; Margin time t _M2 = t _R1 − {l ₂ / V ₁ p + (l ₄ + l _B ) / V ₂ p} (4) FIG. 3 is a flow chart showing the control operation described above, a) shows the first sheet and (b) shows the second sheet.

For the third and subsequent sheets, the data obtained on the previous sheet is sequentially updated and calculated similarly to the second sheet.

The arithmetic processing of each step of the flow chart shown in FIG. 3 is performed by the arithmetic control means 10 shown in FIG. 2, and various data is read and written by the control program storage means 11. The solenoid 5 and the motors 6 and 7 are driven via the drive means 8 in accordance with the result of this arithmetic processing.

(Effects) The present invention is as described above, and according to this method, it is possible to absorb variations in the position of the leading edge of the paper, which is peculiar to the friction separation method (including irregularities in the initial position), mechanical differences, paper differences, and environmental changes over time. It is possible to correct the transport speed that varies due to such factors. Therefore, it is possible to erase the interval that should be taken due to these variations, and it is possible to set the paper interval to be small.

Therefore, the quality of the image forming system is improved by increasing the number of processed sheets at a low linear velocity, and it is possible to obtain a great effect such as an increase in machine life.

[Brief description of drawings]

FIG. 1 is a schematic layout diagram of a sheet feeding device according to the present invention,
FIG. 2 is a functional block diagram of the same embodiment, and FIGS. 3 (a) and 3 (b) are operation flow charts thereof.

Claims (1)

[Claims] 1. A friction separating paper feeding control method in which a friction separating roller pair, a grip roller, and a register roller are sequentially provided on the downstream side of a paper feeding portion, and a resist roller feeds paper through a preliminary paper feeding step and a refeeding step. , A first sensor and a second sensor are sequentially provided between the friction separation roller pair and the grip roller, and a third sensor is further provided between the grip roller and the registration roller. After the paper is fed and stopped at that position, the first conveyance speed conveyed by the friction separation roller pair of the first paper is calculated from the time from the first sensor arranged before the stop position to the second sensor. During the time when the grip roller and the registration roller are conveyed at the preset planned conveyance speed of the grip roller, the first conveyance is performed between the second sensor and the grip roller. The paper feed time is added, and the added value is subtracted from the preset registration start time of the first paper to set the scheduled paper refeed time. Re-feeding, and after the re-feeding, the first paper is conveyed by the grip roller from the time from the grip roller to the third sensor.
The second paper is fed in the same manner as the first paper by correcting the scheduled re-feeding time by the second transport speed instead of the preset planned transport linear velocity of the grip roller. Friction separation paper feed control, wherein after the third paper, the scheduled paper refeed time is corrected by the second transport speed of the immediately preceding paper, and the paper is fed in the same manner as the previous paper. Method.