JPH0757655B2 - Document skew correction device for copiers - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a skew feeding correction device for a document conveyed in the above circulation path of a copying machine that circulates and conveys a sheet document in a sheet document circulation path to perform slit exposure.

2. Description of the Related Art A document fed from a document feeding section is introduced into a loop-shaped circulation path, circulated and conveyed by a preset number of copies, and a contact glass surface provided in contact with a part of the conveyance path. Slide to expose the photoconductor through the exposure system,
A copying machine is known in which a required number of copies are made and a document is discharged to a document tray after a predetermined number of circulations are completed. In this type of copying machine, when the document is skewed due to the condition of the transport path, the skew of the document is accumulated during repeated cyclic transport, and the image is skewed with respect to the paper. Since a copy lacking a part can be made, it is necessary to detect and correct skew feeding (hereinafter referred to as skew) for each circulation.

Conventionally, various skew correction devices have been used and proposed. For example, a method is known in which the skew of the sheet is corrected by inclining the axis of the conveying roller provided in the sheet conveying path with respect to the conveying direction. However, this method causes abrasion of the roller and slippage of the roller surface. The correction amount is likely to change, and it is difficult to properly change the correction value according to the skew.

Further, Japanese Patent Laid-Open No. 57-93848 discloses an oblique feed straightening device as shown in FIGS. To briefly explain this, as shown in FIG. 1, when the document 201 is skewed and conveyed, the skew detection sensors 202, 203
If there is a discrepancy in the detection time of the original due to, and if the deviation is longer than the required time, the solenoid 204 is first detected when the sensor 202 detects the original, and conversely when the sensor 203 first detects the original. The solenoid 205 is actuated to tilt the correction member 206 counterclockwise or clockwise by an angle α with the point P as a fulcrum, and as shown in FIG.
1 is guided by the reversing guide surface 208 of the guide member 207 to correct the skew when reversing.

However, because the correction member is tilted by a certain angle α regardless of the amount of skew, the correction is insufficient or overcorrected, and it is difficult to perform appropriate correction according to the skew amount. Regardless of the width of
Since the tilting angle α of the correction member is constant, a correction amount for a document having a small width is smaller than that for a document having a large width, and as a result, it is difficult to properly correct the width of the document. If the skew amount exceeds a predetermined amount, the correction cannot be completed, and the copy is performed as it is, so that there is a disadvantage that a useless copy having an image defect is taken.

Further, if the document becomes longer, the correction amount of the skew by the guide member 207 becomes larger, and conversely, if the document becomes shorter, the correction amount becomes smaller. Therefore, like a document circulation type copying machine, it has a lower conveyance path and an upper conveyance path that communicates with the upper conveyance path, and a plurality of guide members protruding and retracted to circulate a document to the lower conveyance path are provided in the upper conveyance path. By the operation of
In a copying machine of the type in which one original is repeatedly conveyed on both conveyance paths and a plurality of copies are made from one original, in the case of a long original due to multiple circulation of the original, Since the amount of skew correction each time is large, too much correction will cause skew in the opposite direction, and in the case of a short document, the amount of skew correction will be small each time, so the amount of skew will gradually increase and eventually Has the drawback of making useless copies, with the result that images are missing.

The present invention eliminates the above-mentioned drawbacks of the document skew correcting apparatus of the conventional copying machine which has been implemented and proposed, and particularly the problems when it is applied to a copying machine which circulates and conveys a document a plurality of times. It is another object of the present invention to provide a document skew correcting device capable of correcting the skew amount and the amount corresponding to the size of the document width.

In order to achieve the above object, the present invention enables a pair of curved guide plates that face each other with a space and form a document transport path between the facing surfaces to be tilted about the center line of the width of the transport path. A straightening conveying member arranged in the document circulation path, a driving member mounted on a substrate which tiltably supports the straightening conveying member as described above, and tilting the straightening conveying member, and a conveying direction of the straightening conveying member. On the upstream side, a plurality of sheet document leading edge detection sensors are provided, which are arranged on both sides of the center line of the transport path and are capable of detecting the length of the sheet document in the direction perpendicular to the transport direction,
And a comparison means for inputting a detection signal from the sensor and comparing the detection signal with different detection levels preset according to the length of the sheet document conveyance direction in a direction perpendicular to the sheet document conveyance direction. It is characterized in that the drive member is controlled according to the skew amount and the length of the sheet document in the direction perpendicular to the conveying direction to adjust the tilt amount of the correction conveying member.

The present invention will be described below based on embodiments shown in the drawings.

First, in order to facilitate understanding of the skew correction mechanism, an example of a prototype in which one sheet document leading edge detection sensor is provided on each side of the document conveyance path center line will be described.
In the figure, a support rod 51 is established at approximately the center of a beam-shaped support member 52 stretched between a pair of side plates 71 that are fixed to the main body of the copying machine, and a bearing 54 is attached to the support rod 51. The holding member 53 is rotatably supported at substantially the center thereof. By the bracket 58 on the document conveyance path side of the holding member 53,
Circular arc-shaped inner and outer guide plates 56, 57 are attached so as to form a conveyance path 59 at a predetermined interval, and a holding member 53
The collar 55 is positioned in the thrust direction with respect to the support rod 51.

As shown in FIG. 5, near both ends of the support member 52,
Two sets of support members having a pair of front and rear brackets 62, 62 'are attached to the support rod 51 at positions symmetrical to both sides, apart from the back surface of the holding member 53. Bracket 62,62 ′
The pressing member 63 is slidably fitted into the through hole provided in the press member 63, and the compression spring 65 is interposed between the inner surface of the bracket 64 'and the flange 64 attached to the inside of the bracket 62 of the pressing member 63. As a result, the head of the pressing member 63 is constantly pressed against the back surface of the holding member 53, and the holding member 53 is held at the left and right even positions with respect to the support rod 51 unless an external force is applied.

A pair of solenoids 67 and a pair of solenoids 67 are provided at substantially symmetrical positions on both sides of the support rod 51 of the support member 52 through a bracket 72.
68 are installed. The operating rods of these solenoids 67, 68 are connected to an arm 66 attached to the holding member 53,
Along with the protrusion of the operating rod of each solenoid 67, 68, the holding member 5
The 3 is rotated about the support rod 51.

Next, the structure of the guide plates 56 and 57 will be described in more detail with reference to FIGS.

The curved conveyance path 59 formed between the guide plates 56 and 57 is
Conveying path 82 between guide plates 80, 81 fixed inside the copier body
And is connected to the conveyance path 85 between the guide plates 83, 84,
The sheet original A that has been conveyed in the conveyance path 82 by the conveyance rollers is always fed to the conveyance path 85 through the conveyance path 59.

When the pressing member 63 is in the equilibrium state (neutral position), the conveying path 59 is positioned slightly above the conveying paths 82 and 85 (FIG. 6) and is fed from the conveying path 82. The sheet document A that has come in passes through the conveyance path 59 while curving upward. Next, when the holding member 53 is rotated around the support rod 51 by the operation of one of the first and second solenoids 67 and 68, one side of the transport path 59 with respect to the support rod 51 moves from the neutral position. It moves to the lower position (Fig. 7) and the other side to the upper position (Fig. 8). At this time, the portion of the transport path 59 on the side where the transport path is lowered is as shown in FIG.
And 85 are communicated with each other almost linearly, and as a result, the portion of the sheet document A passing through this position passes through the conveyance path 59 at the shortest distance. Further, the portion of the conveying path 59 on the raised side is further curved upward, as can be seen from FIG. 8, and as a result, the portion of the sheet document A passing through this position is at the neutral position (6th position). It will pass through the inside of the conveyance path 59 through a distance longer than that in the case of FIG. Therefore, one of the solenoids 67 and 68 is operated, and the sheet document A passing through the inside of the conveying path 59 with the holding member 53 being rotated has different conveying distances on both sides thereof.

Next, the skew correction operation of the above-mentioned correction device will be described. As shown in FIG. 9, the skew of the original A is detected by the first and second sensors 31 and 32, and the original A is skewed as shown by the solid line in FIG. 3 or the chain line in FIG. When transported, the second sensor 32 will be the first sensor.
The front end of the document A is detected before 31 and the second solenoid 68 corresponding to the sensor 32 is activated. Then, the holding member 53 rotates and the second solenoid 68 side is lifted, and the right side transport path 59 in FIG. 3 is brought to the state of FIG.
The left transport path 59 is set to the state shown in FIG. As a result, when the document A passes through the conveyance path 59, the end portion on the sensor 32 side that is skewed and passes ahead passes a distance longer than the end portion on the sensor 31 side that follows on the opposite side. A
The skew is corrected when the document A is fed to the transport path 85 due to the difference in the transport distance between the two ends. When the document A is skewed to the opposite side, the skew is similarly corrected by the operation of the sensor 31 and the first solenoid 67. FIG. 10 shows the skew correction unit 23.
An example of a control circuit for controlling (see FIG. 14) is shown.
In the skew detector, the first and second sensors 31 and 32 are composed of light emitting diodes 31a and 32a and phototransistors 31b and 32b. When the light emitted from the light emitting diodes 31a and 32a is reflected by the document, the phototransistors 31b and 32b are
Is turned on, an H level signal is output from the comparators 161 and 162, and is input to the input port I of the microcomputer 180 via the amplifiers 171 and 172, respectively.

As shown in FIG. 11, the microcomputer 180 has a built-in clock pulse generator, first and second counters, first and second drive signal generators and a comparator, and a first sensor 31.
When the first document is detected, the first counter operates to count the number of clock pulses output from the clock pulse generator, and when the second sensor 32 detects the document, the counting is stopped and the first counter The count number is first
Output as a count signal. On the contrary, when the sensor 32 first detects a document, the second counter operates to count the number of clock pulses, and when the first sensor 31 detects a document, the count is stopped and the second counter counts the count number. Output as a count signal.

Next, the operation of the above prototype will be described.

When the document A is skewed and conveyed as shown in FIG. 9, the second sensor 32 first detects the document A, and the H level signal is output from the comparator 162 in FIG. Input port I-2. The second counter starts counting the number of clock pulses output from the clock pulse generator (t _{1 in} FIG. 12), and the document A is further conveyed to the first sensor 31.
When the document A is detected (t _{2 in} FIG. 12), the counting is stopped, and the second counter inputs the second count signal to the second drive signal generator, and the second drive signal generator outputs the second count signal. Is output from the output port P-2 to operate the second solenoid 68 to rotate the skew correcting portion clockwise by an angle α as shown in FIG.

When the document A is conveyed skewed in the direction opposite to that shown, the first sensor 31 first detects the document (see FIG. 12).
t _3), H-level signal from the comparator 161 is output, input to the input port I-1 of the microcomputer 180. When the first counter counts the number of clock pulses and the second sensor 32 detects the document A (t _{4 in} FIG. 12) in the same manner as described above, the counter is stopped. Thus, the first counter outputs the first count signal to the first counter.
The skew correction unit is input to the drive signal generator, and the corresponding first drive signal is output from the output port P-1 from the first drive signal generator to operate the first solenoid 67 to activate the skew correction unit.
Rotate counterclockwise in Fig. 13.

FIGS. 17 to 22 explain an embodiment in which the above prototype example is developed. In this embodiment, four skew sensors 31 to 34 are provided as shown in FIG. The skew correction device corresponds to the four sensors,
As shown in FIG. 19, four solenoids 67 to 70 are provided. The configuration of this embodiment is shown in a block diagram in FIG.
In addition, an example of a control circuit that controls the skew correction unit
Shown in Figure 20. As shown in FIG. 20, each skew sensor 31
~ 34 are light emitting diodes 31a to 34a and phototransistor 31b.
When the light emitted from the light emitting diodes 31a to 34a is reflected by the original, the phototransistors 31b to 34b are turned on, the comparators 161 to 164 output L level signals, and the amplifier Input is made to the input port I of the microcomputer 180 via 171-174.

The description will be continued with reference to the block diagram of FIG.

The microcomputer 180 includes a clock pulse generator and first and second counters 1st to 4th comparing means. When the skew sensors 31 and 33 first detect a document, the first counter operates. Then, the number of clock pulses output from the clock pulse generator is counted, and when the skew sensors 32 and 34 detect a document, the count is stopped. On the contrary, when the skew sensors 32 and 34 first detect a document, the second counter operates to count the number of clock pulses, and when the skew sensors 31 and 33 detect a document, the counting is stopped. If the original is large and the skew sensor 31 first detects the original, the first
The count number of the counter is compared with preset first and second preset numbers, and when the count number is between the first and second preset numbers, a drive signal is output from the output port P-1.
When the number is equal to or larger than the second set number, the drive signal is output from the output port P-2. On the contrary, when the skew sensor 32 first detects a document, the count number of the second counter is compared with the preset first and second set numbers, and the count number is compared with the first and second set numbers. When it is in between, the drive signal is output from the output port P-4, and when it is the second set number or more, the drive signal is output from the output port P-3.

When the document is small in size and the skew sensor 33 first detects the document, the count number of the first counter is compared with preset third and fourth preset numbers, and the count numbers are third and fourth. When it is within the set number, the drive signal is output from the output port P-1, and when it is the fourth set number or more, the drive signal is output from the output port P-2. On the contrary, skew sensor
When 34 detects the original first, the count number of the second counter is compared with preset third and fourth preset numbers, and if the count number is between the third and fourth preset numbers, The drive signal is output from the output port P-4, and when the number is equal to or larger than the fourth set number, the drive signal is output from the output port P-3.

And the output port P-1,2 of the microcomputer 180,
The drive signals output from 3, 4 actuate solenoids 67, 69, 70, 68.

Next, the operation of the embodiment configured as described above will be described.

When the original A is skewed and conveyed as shown in FIG. 17, the skew sensor 32 first detects the original A, the comparator 162 outputs a signal of H level, and the input port I- of the microcomputer 180 is output. Enter in 4. Then, the microcomputer 180 causes the built-in second counter to count the number of clock pulses output from the built-in clock pulse generator (not shown) (t _{1 in} FIG. 21). When the document A is further conveyed and the skew sensor 31 detects the document A, the counting is stopped (t _{2 in} FIG. 21), and the count number of the second counter,
Compared with preset first and second set numbers, if the count number is between the first and second set numbers, a drive signal is output from the output port P-4 and the solenoid 68 is operated to correct the skew. As shown in FIG. 13, the portion 23 is tilted clockwise by an angle α with the support rod 51 as a fulcrum, and if the count number is the second set number or more, a drive signal is output from the output port P-3. , The solenoid 70 is operated to tilt the skew correction portion 23 clockwise by the angle β.

When the document A is skewed and conveyed in the direction opposite to that shown in the drawing, the skew sensor 31 first detects the document (see FIG. 21).
t ₃ ), the H-level signal is output from the comparator 161, and the input port I- of the microcomputer 181 is output.
Enter 1. Then, the microcomputer 180 counts the number of clock pulses until the skew sensor 32 detects the document A (t _{4 in} FIG. 21) in the same manner as described above by the built-in first counter. Compared with preset first and second set numbers, if the count number is between the first and second set numbers, a drive signal is output from the output port P-1, and if the count number is greater than or equal to the second set number. A drive signal is output from the output port P-2 and the solenoids 67 and 69 are operated to tilt the skew correcting portion 23 in the counterclockwise directions by the angles α and β.

When the small-sized original A'is skewed and conveyed as shown in FIG. 3, the skew sensor 34 detects the original,
An H level signal is output from the comparator 174 and input to the input port I-3 of the microcomputer 180. The microcomputer 180 in the same manner as the second counter with a built-counts the number of clock pulses to the skew sensor 33 detects the document A '(t ₅ ~t ₆ of FIG. 21), the The count number is compared with the preset third and fourth preset numbers, and the count number is compared with the third and fourth preset numbers.
If it is within the set number, the drive signal is output from the output port P-4, and if it is equal to or larger than the fourth set number, the drive signal is output from the output port P-3. It is tilted in the directions α and β (see Fig. 22).

When the document A'is conveyed skewed in the direction opposite to that shown in the drawing, the skew sensor 33 first detects the document A ', and the first counter detects the document A'by the skew sensor 34 in the same manner as described above. Clock pulses until (21st
(T ₇ to t _{8 in the} figure) The count number and preset third and fourth numbers
If the count number is compared with the set number and is between the third and fourth set numbers, a drive signal is output from the output port P-1,
If the number is equal to or larger than the fourth set number, a drive signal is output from the output port P-2, and the skew correction unit 23 is tilted counterclockwise by the angles α and β in the same manner as described above.

FIG. 14 shows an example in which the skew correction device as described above is installed in the original circulation type copying machine 131. In a copying machine that makes a large number of copies from such a single original document, the same original document is circulated between the same original document conveyance paths many times, so that the original document that is initially straight has a gradually increased skew. Go.

In FIG. 14, 132 is a document insertion opening, and 134 is a document insertion opening 13
Barriers 137 and 138 that abut against the leading edge of the document fed from 2 to the rising conveyance unit 133, and a pair of friction rollers 137 and 138 that can be contacted and separated by a solenoid 136. As shown in FIG. 15, reference numeral 135 denotes a width sensor composed of four sensors 201 to 208 arranged at predetermined intervals on the right and left sides of the center line of the transport path in a direction orthogonal to the transport direction of the lower transport path. Sensor
Solenoid 136 when any of 201-208 detects a document
Is operated so that the friction rollers 137 and 138 pinch the document without skew. 139 is solenoid 1
A solenoid that operates by the delayed output of 36 to separate the barrier 134 from the conveyance path, 29 is a sensor that measures the length of the document,
As shown in FIG. 16, it is installed on the center line of the conveying path, and the length detecting sensor 29 and the width sensor 135 detect seven kinds of document sizes.

Due to the delayed output from the solenoid 136, the barrier 134 is separated from the inside of the conveyance path by the operation of the solenoid 139, and the roller 138 starts to rotate to start the conveyance of the document.

A conveying roller 140 and a slit exposure unit 141 form an electrostatic latent image on a photosensitive drum (not shown) when a document passes through it.

Reference numerals 143 to 147 denote guide members that protrude to the conveyance path and guide the document to the respective reverse conveyance paths formed by the conveyance rollers 140 and the like.
Reference numerals 3'-147 'are solenoids for projecting the respective guide members 143-147, 142 is a reversing guide plate for reversing the original, and 148 is a discharge tray. When a document is inserted into the document insertion port 132, the sensors 201 to 208 of the width sensor 135 shown in FIG. 15 detect the document. For example, if the document A is A4 size, the sensors 204, 20
5 detects the original, and the detection signal is input to the microcomputer 180 via the amplifier. When the document A is conveyed, the length sensor 29 shown in FIG. 16 detects the document, and the detection signal is input to the microcomputer 180 via the amplifier.

The microcomputer 180 counts the number of clock pulses output from a built-in clock pulse generator (not shown) by a built-in counter (not shown) during the detection period. And the sensor
The document size is obtained from the detection signals from 201 to 208.

When making multiple copies, if the original size is
If it is A4, the microcomputer 180 outputs a drive signal from the A4 output port and operates the solenoid 144 'to cause the guide member 144 to project into the transport path to form a transport loop.

If the original is another size, a guide member according to that size
143-147 are projected. Then, the original is circulated in the formed transport loop, and every time it passes through the slit exposure section 141, copying is performed to make a predetermined number of copies.

Further, the transfer paper for copying is fed from a paper feed tray (not shown) selected in accordance with the magnification of the copy and the like in synchronization with the conveyance of the original based on the information from the original.

After a predetermined number of repeat copies have been made, the guide members 143 to 147 projecting in the transport path are released, and the original document is discharged onto the sheet discharge tray.
It is discharged to 148.

The device 23 for correcting the skew of the document circulated and conveyed in the document circulation path is provided in the conveyance path between the reversal conveyance path 142 and the guide member 143 that passes in any of the conveyance loops from the shortest loop to the longest loop. Has been.

In front of the skew correcting device 23, as shown in FIG. 17, sensors 31 to 34 for detecting the amount of skew of the document are provided on a straight line perpendicular to the conveying direction, and when the document is of small size. If the size of the document is large with 33, 34 sensors, the amount of skew is detected with 31, 32 sensors.

As shown in FIG. 20, the skew amount detection sensors 31 to 34 are
The signal is input to the CPU180.

As shown in FIG. 21, the skew amount is found from the signal of the skew amount detection sensor input to the CPU 180.

First, for large size, left and right skew amount detection sensors
The skew amount is determined based on the number of pulses of the time (or distance) deviation of the 31 and 32 signals by the reference clock pulse (or the encoder pulse matched to the distance of the document). Naturally, make the reference clock pulse (or encoder pulse) fine (short)
The higher the accuracy, the higher the accuracy of skew amount detection.

Similarly, for small sizes, left and right skew amount detection sensors
The amount of time (or distance) deviation between the signals 33 and 34 is determined in the same manner as above.

As shown in FIG. 22, the skew correction device is composed of left and right solenoids 67 to 70. When the inner solenoids 69 and 70 are activated, the inclination is α around the fulcrum of 51, and the outer solenoids are inclined.
When 67 and 68 are activated, they are inclined by β around the fulcrum of 51. With the inclination of α, the skew correction amount is y, and with the inclination of β, the skew correction amount is x. The correction amount is x> y.

FIG. 23 shows a flowchart of the relationship between the skew amount and the skew correction solenoid.

First, it is determined whether or not the original has entered the skew sensors (31 to 34), and if not, different processing is performed. If yes, it is determined whether the original has entered the right skew sensor (34, 32).

If the right skew sensor contains a document, set a flag (ON) to determine whether the left skew sensor has a document.

The amount of skew of the original is until the original enters the skew sensor on the left side, and every time the reference clock pulse (or encoder pulse) enters once during the clock interrupt, the skew amount of the original is entered once in the flow of the clock interrupt. Enter and increment the skew data by +1.

When a document enters the skew sensor on the left side, skew data (here, the number of reference clock pulses or the number of encoder pulses) between them is entered.

If the skew data is x or more, that is, if the skew correction device has a correction amount x (inclination β) or more, the skew is corrected by inclining the correction device β. To correct β, turn on correction SOL68. At that time, FLAG1 is turned off.

If the skew data is smaller than x and equal to or larger than y, the correction device is tilted by α (correction SOL70 is turned on), the skew is corrected, and FLAG1 is turned off.

If the skew data is smaller than y, the solenoid is not operated, FLAG1 is turned off, and the following processing is performed.

Similarly, if there is no document in the right skew sensor (34, 32), it means that the document is in the left skew sensor (31, 33). Therefore, set FLAG1 to ON (ON) and the document in the right skew sensor. The amount of skew of the original is until the mark is entered. Similarly to the above, the skew data includes the number of reference clock pulses or the number of encoder pulses.

If the skew data is x or more, turn on SOL67 and turn off the flag. If the skew data is less than x and y or more, SOL6
9 is turned on, the flag is turned off, and if the skew data is smaller than y, the solenoid is not activated and the flag is turned off to perform the next processing.

By performing the above operation, it is possible to correct the original according to the skew amount of the original.

Naturally, if the number of skew correction solenoids is increased, the correction according to the amount of skew is finely performed.

As described above, according to the present invention, it is possible to properly correct the skew according to the size of the sheet original to be copied and the skew amount in the skew detector.

[Brief description of drawings]

1 and 2 are a plan view and a sectional view showing an example of a conventionally proposed sheet skew correcting device, respectively, and FIG. 3 is a plan view of a skew correcting device of an original example of the present invention, FIGS. 5
FIG. 6 is a sectional view taken along line IV-IV and line VV in FIG. 3, FIGS. 6 to 8 are explanatory views for explaining the operation of the skew correcting conveyance member according to the present invention, and FIG. 9 is a skew detection sensor. FIG. 10 is a schematic diagram for explaining the arrangement and action of FIG. 10, FIG. 10 is a circuit diagram showing an example of a control circuit for controlling the skew correction unit, FIG. 11 is a block diagram for explaining the function of the CPU, and FIG. An example of a timing chart of each element of FIG. 13, FIG. 13 is a schematic diagram for explaining the operation of the solenoid controlled by the control circuit, and FIG. 14 is a cross-sectional view showing the configuration of the document circulation unit of the document circulation type copying machine. FIG. 15 is a schematic diagram showing the document width detecting means, FIG. 16 is a schematic diagram explaining the document length detecting means, and FIG. 17 is a skew correcting device of an embodiment of the present invention applied to this copying machine. Schematic diagram for explaining the arrangement and operation of the skew detection sensor of The control block diagram, No.
FIG. 19 is a plan view of the skew correction device of the embodiment, FIG. 20 is a circuit diagram showing an example of a control circuit for controlling the skew correction unit, and FIG. 21 is an example of a timing chart of each element of the control circuit. FIG. 22 is a schematic diagram for explaining the operation of the four solenoids controlled by the control circuit, and FIG. 23 is a flow chart showing the flow of the operation for performing skew correction according to the skew amount. 23 …… Skew correction device 31,32,33,34 …… Skew detection sensor 51 …… Bend guide plate swing axis 52 …… Substrate 56,57 …… Bend guide plate (correction conveyance member) 59 …… Ban Curved document transport path 67,68,69,70 …… Drive member 180 …… CPU (detection level comparison, control means)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kunio Hibi 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd. (56) References JP-A-57-93848 (JP, A) 60-50639 (JP, U)

Claims (1)

[Claims] 1. A skew feeding correction device for a document conveyed in the circulation path of a copying machine for slit exposure and copying while conveying a sheet document in the sheet document circulation path, facing each other with a space therebetween. A straightening conveying member having a pair of curved guide plates that form a document conveying path therebetween and is tiltably disposed around the center line of the width of the conveying path in the document circulating path. A driving member which is mounted on a substrate that tiltably supports as described above and tilts the straightening and conveying member, and a plurality of sheet originals are arranged on both sides of the center line of the conveying path on the upstream side in the conveying direction of the straightening and conveying member. Sheet document edge detection sensor that can detect the length in the direction perpendicular to the sheet, and the detection signal from this sensor is input, and this is set in advance according to the length in the direction perpendicular to the sheet document conveyance direction. Was done Comparing means for comparing different detection levels is provided, and the drive member is controlled in accordance with the skew amount in the sheet document transport path and the length in the direction perpendicular to the sheet document transport direction to control the tilt amount of the correction transport member. A skew feeding correction device for manuscripts, which is adjusted.