JPH11246131A - Double-sided image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the occurrence of a jam even if a carrying speed of a sheet is quickened by positioning a cutout rotary body in a home position when the sheet reaches a prescribed position before carrying the sheet by the cutout rotary body. SOLUTION: A home position of a D cut roller 12 is detected and stopped in a state L. Therefore, the fact that the D cut roller 12 is surely put in the home position is secured in a state E of starting a carry by rotation of the D cut roller 12 by sheet tip detection on this side of the D cut roller 12. Therefore, afterwards, a position being the home position can be easily specified with every single turn of the D cut roller 12, so that the home position monitoring start timing to stop rotation of the D cut roller 12 is adjusted. By this adjustment, a state F of stopping the D cut roller 12 can be controlled so as to approach a position of a stopping state G by carrying a sheet up to a lateral regist adjusting position only by a reversing roller 10 by stopping the D cut roller 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-sided image processing apparatus having a sheet reversing mechanism and a re-feeding mechanism and capable of processing images on both sides of a sheet.

[0002]

2. Description of the Related Art Many image forming apparatuses such as copiers and printers form an image on only one side of a sheet. However, today, from the viewpoint of environmental protection and resource protection, image formation is performed on both sides of a sheet, that is, so-called double-sided image forming. The device has been commercialized.
In this double-sided image forming apparatus, the sheet on which the image is recorded on one side is inverted, and the sheet is re-fed to the image forming section so that the image is recorded on the other side.

For example, as shown in FIG. 19, a sheet S is conveyed by a conveying roller 100, an image is recorded on the surface by an image forming unit 101, and the sheet is conveyed to a retransmission path 104 by a discharge roller 102 and a flapper 103. After the sheet is conveyed to a predetermined position by the reversing roller 105, the reversing roller 105 is driven to reverse, the sheet is turned over and the sheet is conveyed to the re-feed path 106. Then, after adjusting the lateral registration of the sheet in the re-feeding path, the sheet is again fed to the conveying roller 100 by the D-cut roller 107 and the double-sided conveying roller 108, which are notched rotating bodies with a part of the arc surface cut out. An image is formed on the back side.

[0004]

However, in recent double-sided image forming apparatuses, the sheet conveying speed has been further increased with the improvement of the recording speed. For this reason, there has been a case where a jam (paper jam) occurs during the conveyance due to an increase in the conveyance speed, even though the problem is not caused when the conveyance speed is low.

For example, in the double-sided image forming apparatus,
When the sheet S is conveyed to the position of the D-cut roller 107, the D-cut roller 107 rotates to convey the sheet S, and the roller 107 is moved to the home position (the D-cut surface is opposed to the sheet and is not in contact with the sheet). Position), the home position sensor detects this and stops the rotation of the D-cut roller 107. It is indispensable to stop the D-cut roller 107 at the home position in order to make the sheet S free at the time of performing the lateral registration adjustment.
Therefore, after that, the sheet S is conveyed to the lateral registration position only by the reversing roller 105 without rotating the D-cut roller 107, but the re-feeding path 104 is curved, so that the sheet S is moved to the home position. There is a risk that a load will be applied when passing through the position and jams.

Conventionally, when the D-cut roller 107 starts rotating to convey the sheet S, it has not been determined at which position the cut surface is stopped. When the sheet S is rotated to convey the sheet S, the sheet may immediately return to the home position and stop rotating. In such a case, the conveyance distance of the sheet S by only the reversing roller 105 becomes extremely long, so that the conveyance load may be reduced. Is to be large.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a double-sided image processing apparatus capable of suppressing occurrence of a jam even when a sheet conveying speed is increased.

[0008]

A typical configuration according to the present invention for achieving the above object is a double-sided image processing apparatus having a sheet reversing mechanism and a re-feeding mechanism and capable of performing image processing on both sides of a sheet. Has a notch rotator in which a part of an arc surface for refeeding a sheet on which one-side image processing has been performed is notched, and the sheet reaches a predetermined position before sheet feeding by the notch rotator. The notch rotary body is configured to be located at the home position when the rotation is performed.

In the above configuration, when the sheet is started to be fed by the notched rotator, the notched rotator is always at the home position. For this reason, the notch rotator comes to the home position every rotation from the start of rotation, and the timing of stopping the rotation of the notch rotator can be easily determined. Therefore, by delaying the timing of stopping the rotation of the notched rotator and lengthening the sheet feeding by the rotator, it is possible to reduce the sheet feeding load by the other rotators and suppress the occurrence of a jam.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the double-sided image processing apparatus of the present invention will be specifically described with reference to the drawings.

First Embodiment A two-sided image forming apparatus for recording images on both sides of a sheet will be described as a two-sided image processing apparatus according to a first embodiment with reference to FIGS. still,
FIG. 1 is a schematic cross-sectional explanatory view of a double-sided image forming apparatus, and FIG.
FIG. 3 is a block diagram of a control unit, FIGS. 3 to 6 are flowcharts of a control procedure for re-feeding a sheet, and FIG. 7 is a time chart of a sensor signal and a drive signal.

First, the overall configuration and operation of the double-sided image forming apparatus will be described. In this double-sided image forming apparatus, as shown in FIGS. 1 and 2, in a main body 1, a feeding roller 3 is rotated by a feeding motor M2 from a feeding cassette 2 to feed a sheet. This sheet is transport roller 4
When the leading edge of the sheet conveyed at step S1 passes the feed sensor S1, the main motor M1 and the transport clutch C1 for transmitting the drive stop after a predetermined time from the detection of the leading edge of the sheet by the pre-registration sensor S2. At this time, when a synchronization signal (VSYNC) is input from the video controller A connected by the serial communication line and several signal lines, the registration roller clutch C2
Drive. The developed image is transferred to the photosensitive drum 6 and the sheet is conveyed by a fixing roller 7 and a fixing discharge roller 8.

When double-sided printing is performed, the double-sided flapper 9 is driven by the double-sided flapper solenoid E1 at the time when the leading edge of the sheet is detected by the fixing discharge sensor S3 (state A in FIG. 1), and the sheet is double-sided inverted. Lead to the department. The point when the leading edge of the sheet is detected by the reversing sensor S4 (state B in FIG. 1).
Then, the reversing motor M3 is driven to rotate the reversing roller 10. When the rear end of the sheet has passed through the fixing / discharge sensor S3 and has been conveyed by a predetermined amount (state C in FIG. 1), the sheet is completely in the double-sided reversal section. At this time, the horizontal registration movable plate motor M4 is driven to start moving the horizontal registration movable plate 11 from the home position to the adjustment position. When the trailing edge of the sheet passes through the reversing sensor S4 and is conveyed by a predetermined amount (FIG. 1)
In the state D), the sheet inversion is completed by inverting the inversion motor M3.

When the sheet is conveyed by a predetermined amount from the completion of the sheet reversal and the leading end of the sheet comes before the D-cut roller 12 serving as a notch rotating body with a part of an arc surface cut out (state E in FIG. 1),
The double-sided conveying clutch C3 is driven to rotate the D-cut roller 12. The duplex transport clutch C3 also rotates the duplex transport roller 13 at the same time. Then, after the sheet is further conveyed and the leading end of the sheet has passed through the D-cut roller 12, the D-cut roller home position sensor S5 is monitored to detect the home position (state F in FIG. 1). C3 is stopped, and the rotation of the D-cut roller 12 is stopped. This is to stop the sheet at the home position in the sense that the sheet does not come into contact with the D-cut roller 12 to make the sheet free when the lateral registration adjustment is performed.

Then, only by the rotation of the reversing roller 10,
Further, the sheet is conveyed by a predetermined amount, the reversing motor M3 is stopped, and the sheet is stopped at the position where the lateral registration adjustment is performed (state G in FIG. 1). In this state, the horizontal registration movable plate 11 previously moved to the sheet position fine adjustment position is moved by the horizontal registration movable plate motor M4, and the position of the sheet in the main scanning direction is corrected according to the sheet size. At the start of the sheet position adjustment, the reversing roller pressure releasing solenoid E2 is driven so that the rear end of the sheet biting by the reversing roller 10 is made free so that the movement of the sheet can be easily corrected.

When the adjustment of the sheet position is completed, the double-sided conveying clutch C3 is driven to rotate the D-cut roller 12 and the double-sided conveying roller 13, thereby conveying the sheet again. Then, when the leading edge of the sheet is detected by the double-sided sensor S6 (state H in FIG. 1), the reversing roller pressure releasing solenoid E2 is stopped.
Restrain the rear end of the sheet. The front end of the sheet is a double-sided conveyance roller 13
At a predetermined time after passing (state I in FIG. 1), the horizontal registration movable plate 11 regulated by the sheet position adjustment is returned to the home position. When the sheet is further conveyed by a predetermined amount and the leading end of the sheet reaches just before the nip of the conveying roller 4 (state J in FIG. 1), the reversing motor M3 and the double-sided conveying clutch C3 are stopped to stop the sheet conveying. This completes the double-sided conveyance, and waits until the sheet is re-fed by the print instruction for the second side sent from the video controller A.

In response to a print command from the video controller A, the reversing motor M3, the double-sided conveying clutch C3, and the conveying roller 4 are driven to restart sheet conveyance, and the sheet sensor S1 detects the leading edge of the sheet and conveys a predetermined amount. (The state K in FIG. 1), the reversing motor M3 and the double-sided conveying clutch C
3 stop. Then, the main motor M1 and the transport clutch C1 for transmitting the drive stop after a predetermined time from the detection of the leading edge of the sheet by the pre-registration sensor S2. When a synchronization signal (VSYNC) is input from the video controller A, the registration roller clutch C2 is driven to rotate the registration roller 5. On the sheet, the image on the second surface developed on the photosensitive drum 6 is transferred, and the fixing roller 7
Then, the sheet is conveyed by the fixing discharge roller 8, and the sheet is guided to the discharge roller 14 without being driven by the double-side flapper solenoid E 1, and is discharged to the discharge stacking tray 15.

The drive control of the above members is performed by control means shown in FIG. In FIG. 2, a microcomputer (CPU) is mounted on the double-sided printing apparatus, and is connected to the video controller A via a serial communication line and several signal lines. The sensor input circuits B1 to B7 are sensor input circuits of the respective sensors in FIG.
Input to PU. A feed sensor signal (FEEDS) is input from the feed sensor S1 via the sensor input circuit B1, a pre-registration sensor signal (REGS) is input from the pre-registration sensor S2 via the sensor input circuit B2, and a fixing discharge sensor S3 , A fixing discharge sensor signal (FPOUTS) is input via a sensor input circuit B3. Also, the inversion sensor signal (SWBKS) is output from the inversion sensor S4 via the sensor input circuit B4.
), A D-cut roller home position sensor signal (DRHPS) is input from the D-cut roller home position sensor S5 via the sensor input circuit B5, and a double-sided sensor signal (DUPS) is input from the double-sided sensor S6 via the sensor input circuit B6. ) Is entered. Further, a horizontal resist movable plate home position sensor signal (HRHPS) is input from the horizontal resist movable plate home position sensor S7 via the sensor input circuit B7.

The driving circuits D1 to D9 are driving circuits for the respective driving members shown in FIG. 1, and are driven by driving signals output from the CPU. The main motor M1 via the drive circuit D1 according to the main motor drive signal (MMD)
And drives the feed motor M2 through the drive circuit D2 by the feed motor drive signal (FEEDMD), and inverts the drive motor D3 through the drive circuit D3 by the reverse motor drive signal (SWBKMD) and the rotation direction instruction signal (SBDIRD). Drive the motor M3. In addition, the lateral registration movable plate motor M4 is driven via the drive circuit D4 by the lateral registration movable plate motor drive signal (HREGMD) and the rotation direction instruction signal (HRDIRD), and the drive circuit D5 is supplied by the feed conveyance clutch drive signal (FEEDCLD). , And drives the registration roller clutch C2 through the drive circuit D6 by the registration roller clutch drive signal (REGCLD). Further, a double-sided flapper solenoid drive signal (DUPSLD) drives a double-sided flapper solenoid E1 via a drive circuit D7, and a double-sided transfer clutch drive signal (DUPCLD) drives a double-sided transfer clutch C3 via a drive circuit D8. Drive circuit D9 by pressure release solenoid drive signal (hereinafter referred to as SFSLD)
Is used to drive the reversing roller pressure releasing solenoid E2.

Next, a sheet feeding control procedure for performing double-sided printing by the control means will be described with reference to flowcharts of FIGS.

In step S301, the fixing discharge sensor signal (FPOUTS) is checked, and the process waits until the fixing discharge sensor S3 detects the leading edge of the sheet. When the leading edge of the sheet is detected, the double-sided flapper 9 is driven in step S302,
Guide the sheet to the double-sided turnover. Next, in step 303, the reverse sensor signal (SWBKS) is checked, and the reverse sensor S
Wait until 4 detects the leading edge of the sheet. When the leading edge of the sheet is detected, in step 304, the driving of the double-sided flapper 9 is stopped, and the reversing motor M3 is rotated forward.

Next, at step 305, the fixing discharge sensor signal (FPOUTS) is checked again, and the fixing discharge sensor S3 is checked.
Waits until the trailing edge of the sheet is detected. When the trailing edge of the sheet is detected, the movement of the horizontal registration movable plate 11 to the adjustment position is started in step 306.

Thereafter, at step 307, the reverse sensor signal (SWBKS) is checked again, and the process waits until the trailing edge of the sheet is detected. If the sheet trailing edge is detected, go to step 30
In step 8, a predetermined movement amount is set, and in step 309, the completion of movement of the predetermined amount is waited. After the movement is completed, in step 310, the reverse motor M3 is rotated in the reverse direction. Then, in step 311, a predetermined movement amount is set, and in step 312, the completion of movement of the predetermined amount is waited. After the movement is completed, in step 313, the double-sided conveying clutch C3 is driven to rotate the D-cut roller 12.

In this embodiment, when the sheet is conveyed by a predetermined amount by the reverse rotation of the reversing roller 10, the D-cut roller
The control is performed to rotate 12 and stop it by detecting the home position.

That is, in step S313, the double-sided conveyance clutch 228 is driven to start the rotation of the D-cut roller 12, and in step 401, a predetermined moving amount (about two rotations of the D-cut roller 12) is set. Then, while checking the D-cut roller home position sensor signal (DRHPS) at step 402, the process waits for the completion of a predetermined amount of movement at step 404. During this time, the home position of the D-cut roller 12 is detected in step 402, and if the home position is detected, the double-sided conveyance clutch C3 is stopped in step 403 to stop the rotation of the D-cut roller 12 at the home position. .

Thereafter, in step S314, a predetermined movement amount is set, and in step 315, the completion of movement of the sheet by the predetermined amount is waited. After the movement is completed, at step 316, a predetermined movement amount is set, and at step 317, the D-cut roller home position sensor signal (DRHPS) is checked while
At 319, the control waits for the completion of the predetermined amount of movement. During this time, if the D-cut roller home position sensor signal (DRHPS) detects the home position at step 317, the double-sided transfer clutch C3 is stopped at step 318, and the rotation of the D-cut roller 12 is stopped at the home position. .

Next, after the movement is completed, in step 320, the double-sided conveyance clutch C3 and the reversing motor M3 are stopped, and the reversing roller pressure releasing solenoid E2 is driven to make the rear end of the sheet free. Next, in step 321, the adjustment of the horizontal resist movable plate 11 is started, and in step 322, the completion of the adjustment is awaited.

Next, after the adjustment is completed, in step 323, the reverse motor M3 is rotated in reverse to drive the duplex transport clutch C3 to transport the sheet. In step 324, the duplex sensor signal (DUPS) is checked. Wait until the tip is detected. Then, when the sheet leading edge is detected, step 325 is executed.
To stop the reversing roller pressure releasing solenoid E2 to restrain the rear end of the sheet.

Next, at step 326, a predetermined moving amount of the sheet is set, and at step 327, the completion of the moving of the predetermined amount is waited. After the movement is completed, the horizontal resist movable plate 11 is
To move to the home position. Step 32
At step 9, a predetermined movement amount is set, and at step 330, the completion of the movement of the predetermined amount is waited.

Next, at step 331, the double-sided conveyance clutch C3 is stopped, the reversing motor is stopped, and the sheet conveyance is stopped. Then, in step 332, the process waits until a re-feed instruction is issued. When the re-feed instruction is issued, in step 333, the reverse motor M3 is rotated in the reverse direction to rotate the double-sided conveying clutch C3.
To restart the sheet conveyance.

Next, at step 334, a predetermined movement amount of the sheet is set, and at step 335, the completion of the movement of the predetermined amount is waited. After the movement is completed, in step 336, the double-sided conveyance clutch C3 is stopped, the reversing motor M3 is stopped, and the conveyance is performed by the conveyance roller 4, and the double-sided conveyance control is ended.

FIG. 7 shows a time chart of the sensor signal and the drive signal. In FIG. 7, t1 is a fixing discharge sensor S3.
Is the time from when the leading edge of the sheet is detected to when the trailing edge of the sheet is detected, and t2 is the time when the double-sided flapper solenoid E1 is driven and the double-sided flapper 9 guides the sheet to the double-sided reversing section. T3 is the time from when the reversing sensor S4 detects the leading edge of the sheet to when it detects the trailing edge of the sheet. This is the time for the roller 10 to convey the sheet to the horizontal registration adjustment position. t6 is the time from when the D-cut roller 12 rotates by driving the double-sided conveying clutch C3 to when the D-cut roller 12 reaches the home position and stops rotating.
It is the time to carry it alone. t8 is a horizontal resist adjustment time. t9 is a time for conveying the sheet to a position before the conveying roller 4, and t10 is a time for waiting for a re-feed instruction. t11 is a time until the sheet is conveyed to the position where it passes the feed sensor S1 and the reversing roller 10, the D-cut roller 12, and the both-side conveying roller 13 are stopped. t12 represents the time from when the duplex sensor S6 detects the leading edge of the sheet to when it detects the trailing edge of the sheet. t13 is a time from when the double-sided conveying clutch C3 is driven to rotate the D-cut roller 12 until it stops at the home position detection.

In the conventional sheet re-feeding procedure at the time of double-sided recording, steps S401 to S40 shown in FIG.
Since the control of FIG. 5 was not performed, as shown in the time chart of the conventional sensor signal and drive signal shown in FIG.
There is no control of

Comparing the time chart of this embodiment shown in FIG. 7 with the conventional time chart shown in FIG. 8, control of t13 is added in this embodiment, so that t6 becomes longer and t7 becomes shorter. It is characterized by having.

Accordingly, in the present embodiment, the home position of the D-cut roller 12 is detected and stopped in the state L shown in FIG. In the state E in which the conveyance by rotation is started, it is guaranteed that the D cut roller 12 is always at the home position. Therefore, the position at which the D-cut roller 12 becomes the home position can be easily specified for each rotation of the D-cut roller 12, and the timing of starting the home position monitoring for stopping the rotation of the D-cut roller 12 can be adjusted. The stop state F can be controlled to approach the state G in which the D-cut roller 12 stops and is conveyed to the lateral registration adjustment position only by the reversing roller 10 to stop.

More specifically, FIG. 9 is a diagram showing a control positional relationship, in which (a) relates to the present embodiment, and (b) to (d) relate to a conventional example. Things.

In this embodiment, as shown in FIG. 9A, the D-cut roller 12 is always at the home position in the state E. The position to be the home position for each rotation can be easily specified. Therefore, the home position of the D-cut roller 12 is started to be monitored at a timing after the home position immediately before the stop at the home position, and the rotation of the D-cut roller 12 is stopped at the next home position detection (state F). ).

Then, both the timing of the state F at which the rotation of the D-cut roller 12 is started and the timing of starting the home position monitoring of the D-cut roller 12 are determined.
In this case, the distance between the positions F and G can be easily adjusted optimally in consideration of a margin such as a sensor width for detecting the home position by shifting the position back and forth according to one rotation.

On the other hand, in the prior art, since the notch surface of the D-cut roller was indefinite in the state E, FIGS.
As shown in (d), ((b) shows the state where the D cut roller is at the home position in state E, and (c) shows the state where the D cut roller is in the state E.
When the cut roller is at a position shifted by 180 degrees from the home position, (d) indicates when the D cut roller is at a position delayed by 90 degrees from the home position in the state E). The state F in which the rotation is stopped at the home position of the D-cut roller varies, causing the distance between the positions F and G to vary and become longer.

In this embodiment, as described above, the time t6 during which the sheet is conveyed by both the D-cut roller 12 and the reversing roller 10 shown in FIG. 7 can be lengthened. The time t7 when the load is large enough to carry
Can be shortened. Therefore, the load is reduced, and it is possible to carry the paper without causing a jam even at the time of high-speed carrying.

[Second Embodiment] Next, a second embodiment to which the present invention can be applied will be described with reference to FIGS. In this embodiment, the overall configuration of the apparatus and the configuration of the control means are the same as those of the above-described first embodiment, and only a part of the sheet re-feeding procedure is different, and the other parts are the same. I do.

FIGS. 10 to 13 are flowcharts showing a sheet re-feeding control procedure according to the second embodiment. In this embodiment, in FIG. 1, the D-cut roller 12 is moved to the home position between the state D and the state E, that is, when the sheet is conveyed by a predetermined amount by the reverse rotation of the reversing roller 10 (state L in FIG. 1). Only when the position is not the position, a control is performed in which the D-cut roller 12 is rotated and stopped by detecting the home position.

The sheet re-feeding procedure according to this embodiment eliminates the processing of step S313 of FIG. 3 in the first embodiment, and replaces steps S401 to S405 of FIG. 4 with processing of steps S501 to S506 of FIG. That
Other controls are the same as in the first embodiment.

That is, when the sheet is in the state L in FIG. 1, a predetermined moving amount (conveyance distance to the state E in FIG. 1) is set in step S501, and in step S502, the D-cut roller home position sensor signal (DRHPS) is set. ), While waiting for the completion of the movement of the predetermined amount of sheets in step S505. During this time, the home position of the D-cut roller 12 is detected in step S502. If it is not the home position, the double-sided conveyance clutch C3 is driven to rotate the D-cut roller 12 in step S504. If it is the home position, the process proceeds to step S503. To stop the double-sided conveying clutch C3 and stop the D-cut roller 12 at the home position. Thereafter, when the movement of the sheet by the predetermined amount is completed, the double-sided conveyance clutch C3 is driven in step S506 to
Start rotation. Then, control is performed so as to proceed to step S314.

In this series of processing, if the sheet is in the state L in FIG. 1 and the D-cut roller 12 is already at the home position, the state shifts to the state E in FIG. If the D-cut roller 12 is not at the home position, control is performed to rotate the D-cut roller 12 until the D-cut roller 12 is at the home position and then shift to the state E.

In the present embodiment, when the D-cut roller 12 is already at the home position, the rotation of the home position detection is not performed when the D-cut roller 12 is already at the home position. Has the effect of suppressing.

The time chart of the sensor signal and the drive signal in the present embodiment is the same as the time chart in FIG. 7 in the first embodiment. However, in the present embodiment, when the sheet is in the state L in FIG.
Is not in the home position, the control for setting the D-cut roller 12 to the home position is not performed. Therefore, t13 in the time chart of FIG. 7 is different from that of the first embodiment in that t13 = 0.

As in the first embodiment, in the state E in which the conveyance by the rotation of the D cut roller 12 is started by detecting the leading edge of the sheet before the D cut roller 12, the D cut roller 12
Is guaranteed to be in the home position. Therefore, by adjusting the timing of starting the home position monitoring after the conveyance by the D-cut roller 12 as described in the first embodiment, the load that the D-cut roller 12 is stopped and conveyed only by the reversing roller 10 is adjusted. This makes it possible to shorten the time required for the transfer, and to make it possible to carry out conveyance without causing a jam even at the time of high-speed conveyance.

[Third Embodiment] Next, a third embodiment to which the present invention can be applied will be described with reference to FIGS. In this embodiment, the overall configuration of the apparatus and the configuration of the control means are the same as those of the above-described second embodiment, and only a part of the sheet re-feeding procedure is different, and the others are the same. I do.

FIGS. 14 to 17 are flowcharts showing a sheet re-feeding control procedure according to the third embodiment, and FIG. 18 is a time chart of sensor signals and drive signals relating to sheet re-feeding.

In this embodiment, the D-cut roller 12 is not at the home position between the state D and the state E shown in FIG. Only when the re-feeding is completed (state K in FIG. 1), a control is provided to rotate the D-cut roller 12 and stop it upon detecting the home position.
It is characterized in that it has a control to stop the conveyance when the D-cut roller 12 has reached the home position.

The re-feeding control procedure of this embodiment is a flowchart of the second embodiment. FIGS. 10 to 13 are different from steps S335 and S336 of FIG. 13 in that steps S601 to S604 of FIG. 17 are added. Is different.

That is, when the sheet is in the state K in FIG. 1, after the carrying roller 4 takes over the carrying in step 335, a predetermined moving amount (about one rotation of the D-cut roller 12) is set in step S601. While checking the D-cut roller home position sensor signal (DRHPS) in step S602, the process waits for completion of a predetermined amount of movement in step S604. During this time, while the home position of the D-cut roller 12 is detected in step S602, if the home position is detected, the double-sided conveying clutch C3 is stopped in step S603 to stop the D-cut roller 12 at the home position. Then, after the movement of the predetermined amount is completed, in step S336, the double-sided conveyance clutch C3 and the reversing motor M3 are stopped to end the double-sided conveyance control.

By controlling the D-cut roller 12 to be at the home position at the end of the double-sided control, the double-sided conveyance control is started in the next double-sided recording, and the sheet is moved in the state L in FIG. When the home position is checked, the home position is already at the home position, so there is no need to perform rotation to match the home position again.

This means that the number of times of driving and stopping the double-sided conveying clutch C3 can be reduced by one time as compared with the second embodiment, and has the effect of improving the durability of the clutch. However, if the sheet is long and the trailing edge of the sheet still remains on the double-sided conveying roller 13 in the state of the state K in FIG. 1, even if the D-cut roller 12 is stopped in accordance with the home position, the conveying roller 4 When the sheet is re-fed, the double-sided conveying roller 13 also rotates. At this time, since the double-sided conveyance clutch C3 is connected to the D-cut roller 12 and the double-sided conveyance roller 13, the double-sided conveyance roller 13 rotates, so that the D-cut roller 12 also rotates and the home position is not maintained.

Therefore, the home position of the D-cut roller 12 is not guaranteed at the end of the two-sided conveyance control for only such a long sheet.
When the state L is reached, the D-cut roller 12 is not at the home position, but rotates to the home position.

Therefore, only when the previous double-sided recording sheet is short, the number of times the double-sided conveying clutch C3 stops driving can be reduced by one.

The sensor signal and the drive signal according to the third embodiment will be described with reference to time charts in FIGS. However, in FIG. 7, similarly to the second embodiment, when the sheet is in the state L of FIG. 1 and the D cut roller 12 is already at the home position, control is performed to set the D cut roller 12 to the home position. Therefore, t13 in FIG. 7 becomes t13 = 0. Further, t11 is the time from when the re-feed instruction is issued, when the conveyance of the predetermined amount is completed, the sheet is brought to the state K in FIG. 1, and the D-cut roller 12 is further brought to the home position.

FIG. 18 is a flowchart when the sheet is long. Similarly, t11 is the time from when the re-feeding instruction is issued, when the conveyance of the predetermined amount is completed, the sheet enters the state K in FIG. 1, and the D-cut roller 12 further returns to the home position. Here, since the sheet is long even after the end of t11, the sheet is present in the two-sided sensor S6 at t12, and the timing at which the two-sided conveying roller 13 rotates with the subsequent conveyance by the conveying roller 4 is shown. ing.

In such a case, since the D cut roller 12 is not at the home position in the next double-sided conveyance control, the rotation for setting the home position is always performed at t13.

Accordingly, as in the first and second embodiments described above, in the state E in which the conveyance by the rotation of the D-cut roller 12 is started by detecting the leading edge of the sheet before the D-cut roller 12, the D-cut roller 12 is always home. You are guaranteed to be in position. Therefore, by adjusting the timing of starting the home position monitoring after the conveyance by the D-cut roller 12 as described in the first embodiment, the load that the D-cut roller 12 is stopped and conveyed only by the reversing roller 10 is adjusted. This makes it possible to shorten the time required for the transfer, and to make it possible to carry out the conveyance without causing a jam even at the time of high-speed conveyance.

[Other Embodiments] In the above-described embodiment, a double-sided image forming apparatus for recording an image on both sides of a sheet is excited. However, the present invention is not limited to the image forming apparatus, but also includes a document on which images are described on both sides. A double-sided image reading apparatus in which a sheet is fed and double-sided information of the document is read by a reading unit can be suitably used.

[0063]

According to the present invention, in a double-sided image processing apparatus capable of performing double-sided image processing with a sheet reversing mechanism and a re-feeding function, the notch rotator always starts rotating for sheet conveyance by the notch rotator. Since the home position is set, the timing at which the home position comes every rotation after the start of rotation can be easily defined.

Therefore, the timing of stopping the rotation can be determined by adjusting the timing of starting the monitoring of the home position of the notched rotator. By delaying the timing of stopping the rotation of the notched rotator as much as possible, a large load is conveyed only by the reversing roller. Since the distance can be reduced, the occurrence of a jam can be suppressed even when the sheet conveying speed increases.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional explanatory view of a two-sided image forming apparatus.

FIG. 2 is a configuration block diagram of a control unit.

FIG. 3 is a flowchart of a sheet re-feeding control procedure.

FIG. 4 is a flowchart of a sheet re-feeding control procedure.

FIG. 5 is a flowchart of a sheet re-feeding control procedure.

FIG. 6 is a flowchart of a sheet re-feeding control procedure.

FIG. 7 is a time chart of a sensor signal and a drive signal.

FIG. 8 is a time chart of a sensor signal and a drive signal in a conventional double-sided image forming apparatus.

FIGS. 9A and 9B are diagrams showing a positional relationship between the home position of the D-cut roller and control of rotation stop, wherein FIG. 9A shows a positional relationship according to the present embodiment, and FIGS. It shows a positional relationship.

FIG. 10 is a flowchart of a sheet re-feeding control procedure according to a second embodiment.

FIG. 11 is a flowchart of a sheet re-feeding control procedure according to the second embodiment.

FIG. 12 is a flowchart of a sheet re-feeding control procedure according to the second embodiment.

FIG. 13 is a flowchart of a sheet re-feeding control procedure according to the second embodiment.

FIG. 14 is a flowchart of a sheet re-feeding control procedure according to a third embodiment.

FIG. 15 is a flowchart of a sheet re-feeding control procedure according to the third embodiment.

FIG. 16 is a flowchart of a sheet re-feeding control procedure according to the third embodiment.

FIG. 17 is a flowchart of a sheet re-feeding control procedure according to the third embodiment.

FIG. 18 is a time chart of a sensor signal and a drive signal of sheet re-feeding according to the third embodiment.

FIG. 19 is a schematic diagram illustrating a configuration of a two-sided image forming apparatus according to the related art.

[Explanation of symbols]

 A: Video controller B1 to B7: Sensor input circuit C1: Transfer clutch C2: Registration roller clutch C3: Double-sided transfer clutch D1 to D9: Drive circuit E1: Double-sided flapper solenoid E2: Reverse roller pressure release solenoid M1: Main motor M2: Supply Feeding motor M3 ... reversing motor M4 ... lateral registration movable plate motor S1 ... feeding sensor S2 ... pre-registration sensor S3 ... fixing discharge sensor S4 ... reversing sensor S5 ... D-cut roller home position sensor S6 ... double-sided sensor S7 ... horizontal registration movable plate Home position sensor 1… Main unit 2… Feed cassette 3… Feed roller 4… Transport roller 5… Registration roller 6… Photoconductor drum 7… Fixing roller 8… Fixing discharge roller 9… Double-sided flapper 10… Reversing roller 11… Horizontal Resist movable plate 12… D-cut roller 13… Double-sided conveyance Over La 14 ... discharge rollers 15 ... discharged and stacked trays

Claims (4)

[Claims] 1. A double-sided image processing apparatus having a sheet reversing mechanism and a re-feeding mechanism capable of performing image processing on both sides of a sheet, wherein a part of an arc surface for re-feeding a sheet on which one side image processing has been performed is provided. A notch rotator, wherein the notch rotator is positioned at a home position before the sheet is fed by the notch rotator and the sheet reaches a predetermined position. Double-sided image processing device. 2. The double-sided image processing apparatus according to claim 1, wherein the notch rotator is rotated to feed a sheet, and the notch rotator is controlled to stop at a home position after a predetermined rotation. . Detecting whether or not the notched rotary member is at a home position before sheet feeding by the notched rotary member;
The double-sided image processing apparatus according to claim 1, wherein the notch rotator is driven to be positioned at the home position only when not at the home position. 4. When the sheet is re-fed by the notch rotator and the sheet is conveyed by a predetermined amount by a conveyance rotator downstream of the notch rotator in the sheet feeding direction, the notch rotator is used. 4. The double-sided image processing apparatus according to claim 3, wherein the drive of the notch rotator is stopped at a time point when is located at the home position.