JPS629499B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a paper skew feed correction device for a copying machine that corrects a paper such as a transfer paper or an original document to a normal state when the paper is fed diagonally.

2. Description of the Related Art Conventionally, a copying machine is provided with a conveyance device for conveying paper such as transfer paper or original documents. These conveying devices are provided with a correction device for correcting this problem to a normal state, because if the paper is fed diagonally, it may cause a paper jam. Many correction devices use multiple feed rollers with different diameters,
The inclination of the paper is corrected by tilting the roller shaft with respect to the paper transport direction, but with these correction devices, the amount of correction changes significantly if the roller wears or slippage occurs on the roller surface. Therefore, even if the amount of correction is determined by detecting the amount of skew of the paper, there is a drawback that the paper cannot necessarily be corrected to a normal state.

The present invention has been made to eliminate such drawbacks, and includes providing a guide member on a paper transport path that reverses the paper transport direction, and controlling the angle of this guide member with respect to the paper transport direction in accordance with the amount of skew. An object of the present invention is to provide a paper skew feeding correction device for a copying machine which corrects the paper skew to the correct state by correcting the paper skew, thereby reliably preventing skew paper feeding and paper jams caused by the skew feeding.

The present invention will be described in detail below with reference to an illustrated embodiment. In the figure, reference numeral 1 denotes a paper conveyance means provided in a copying machine (not shown), which is capable of conveying a paper 3 along a conveyance path 2 by a plurality of feed rollers 1a. Reference numeral 4 denotes a guide member installed in the middle of the conveyance path 2, which is installed perpendicular to the conveyance direction of the paper 3, and is rotated at an angle about a pivot shaft 4a by a driving means 5 such as a solenoid connected to both ends. The guide member 4 can be rotated by α, and a number of paper guides 6 are provided protruding from the side surface of the paper conveyance path 2 of the guide member 4. These paper guides 6 reverse the course of the paper 3 transported along the transport path 2, and have a semicircular curved surface 6a on the transport path 2 side. The paper 3 fed on the paper 3 is guided along the curved surface 6a and reversed toward the transport path 2a, and if the paper 3 is fed diagonally, this is corrected as follows. I'm starting to do that. Note 9
is the biasing means.

That is, in front of the guide member 4, a pair of paper detectors 7 and 8 are installed spaced apart in a direction perpendicular to the transport direction of the paper 3.
The signals a and b detected by 8 are input to the control circuit shown in FIG. Next, to explain the above control circuit including the correction operation, the one shot multivibrator 9 is provided with a variable resistor 10 in the control circuit. Set constants in advance. Now, the sheet 3 is conveyed by the conveying means 1 on the conveying path 2 toward the guide member 4, and when the leading edge reaches the detectors 7 and 8, if the sheet 3 is being conveyed normally, each detector 7 and 8 The detectors 7 and 8 detect the paper 3 at the same time, or with a time difference when the paper 3 is fed diagonally as shown by the broken line in FIG. The signals a and b detected by these detectors 7 and 8 are input to an OR gate 11,
As a result, the paper detection signal c is output to the output side of the OR gate 11. Detection signal c is inverter 1
2. The signal d is input to a pulse generation circuit consisting of a delay 13 and an AND gate 14, and a signal d having a pulse width equal to the delay amount of the delay 13 is generated.
This signal d passes through the OR gate 15 and outputs the clock signal g to the latch circuits 16, 17, 18, 19, and at the same time triggers the one-shot multivibrator 9. Therefore, the one-shot multivibrator 9 is connected to the variable resistor 10. The output signal e is set to "0" for a period corresponding to a time constant determined by the set resistance value and the capacitor 20. When the above period elapses and the output signal e changes from "0" to "1", the inverter 21, delay 22 and
The pulse generation circuit of the AND gate 23 generates a signal f having a pulse width equal to the delay amount of the delay 22, and this signal f passes through the OR gate 15 to the latch circuits 16, 17, 18, and 19 to generate the clock signal g. At the same time as outputting
After being delayed by , it is input to latch circuits 25 and 26 as a clock signal h. That is, the states of the outputs _a and b of the detectors 7 and 8 at the time to when the leading edge of the paper 3 reaches the detectors 7 and 8 are stored in the latch circuits 16 and 17, respectively, by the clock signal g (=d). Ru. Also, variable resistor 10 and capacitor 2
The states of the outputs a and b of the detectors 7 and 8 at time t _o +1, which is delayed from the above-mentioned time t _o by the time determined by 0, are also applied to the latch circuits 16 and 17, respectively, by the clock signal g (=f). At the same time as being stored, the contents stored in the latch circuits 16, 17 at the _time to are further transferred to the latch circuits 18, 19 and stored therein. The output "Q" of the latch circuits 18 and 19 is the output "" of the latch circuits 16 and 17.
AND gates 27 and 28 whose other input is
is connected, and the presence or absence of skewed paper feeding and the skewed feeding direction are determined as follows. That is, one of the two inputs of the AND gate 27 is the output signal m of the latch circuit 18, which is the state of the output a of the detector 7 at the time t _o , and the other is the state of the output a of the detector 7 at the time to.
7, which is the inversion of the state of the output b of the detector 8 at the time t _o +1. Therefore, the output signal Q of the AND gate 27 outputs "1" only when the signal a precedes the signal b and the time difference therebetween is greater than or equal to the skew allowable amount t _o +1-t _o . Also, one of the two inputs of the AND gate 28 is the output signal n of the latch circuit 19, and the output b of the detector 8 at the time t _o
and the other is the output signal j of the latch circuit 16, which is the inversion of the state of the output a of the detector 7 at time t _o +1. Therefore, the output signal P of the AND gate 28 will output "1" only when the signal b precedes the signal a and the time difference therebetween is greater than or equal to the skew allowance t _o +1-t _o . These output signals Q and P are stored in the latch circuits 25 and 26 as a clock signal h as the discrimination results, and the outputs Q and R of the latch circuits 25 and 26 are stored in the buffers 29 and 3.
0 to become skew correction signals s and t, the driving means 5 is operated and skew correction is performed as follows.
If the paper 3 is conveyed diagonally as shown in FIG. 3, when the detectors 7 and 8 detect this, the guide member 4 is moved in the direction of arrow a about the pivot 4a according to the amount of skew.
direction by an angle α. As a result, when the leading edge of the paper 3 reaches the curved surface 6a of the paper guide 6, one end side, that is, the side first detected by the detector 8, is guided along A'-B'-C' of the curved surface 6a.
Later, the side detected by the detector 7 is guided along A-B-C of the curved surface 6a while reversing its course, and the skew of the paper 3 is corrected by the difference in the transport distance at this time, and the guide Paper guide 6 of member 4
The sheet 3 that has been reversed at step 3 assumes a normal conveying posture as shown by the broken line in FIG. 3, and is then conveyed to the next process.

In addition, FIG. 6 is a timing chart showing the operation of the control circuit, FIG. 7 is a timing chart showing another embodiment in which a pulse motor 5' is used as the drive means 5, and FIG. 8 is a timing chart showing the operation of the pulse motor 5'. This shows the control circuit. That is, when the paper 3 is in a skewed state and after one detector 7 detects the leading edge of the paper 3, the other detector 8 detects the leading edge of the paper 3, for example, at the fifth pulse of the output H of the timer 32. The pulse motor control circuit 33 outputs a control signal corresponding to the number of pulses to the drive circuit 34, whereby the pulse motor 5' is rotated and the guide member 4 is rotated, for example, 5 times according to the time difference between the signals a and b. The paper 3 is driven by a pulse amount through a gear train 35 around the pivot 4a to correct the skew feeding of the paper 3, and the above operation is shown in a timing chart as shown in FIG. 9.

As described in detail above, this invention detects the amount of paper skew using at least a pair of detectors provided on the paper transport path, and rotates the guide member based on the obtained signal to change the paper transport distance. By correcting the skew of the paper, it is possible to always perform an appropriate correction compared to conventional correction rollers, etc., and the amount of correction is not affected by roller wear. , high reliability can be obtained over a long period of time.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a plan view, FIG. 2 is a side view, FIGS. 3 and 4 are action explanatory diagrams, FIG. 5 is a circuit diagram of the control circuit, and FIG. 7 is an explanatory diagram of another embodiment, FIG. 8 is a circuit diagram of a control circuit, and FIG. 9 is a timing chart of the same. 2 is a transport path, 3 is paper, 4 is a guide member, 7,
8 is a detector.

Claims (1)

[Claims] 1. A guide member 4 is provided on the transport path 2 of the paper 3 so as to be tiltable with respect to the course of the paper 3 by slidingly contacting the paper 3 and reverse the course of the paper 3, and a guide member 4 is provided on the paper transport path side of the guide member 4. A paper skew feed correction device for a copying machine, which is provided with automatic adjustment means for automatically adjusting the inclination of the guide member 4 in accordance with a skew signal from a detector 78 provided therein.