JPH09263346A - Sheet position detecting method, sheet carrying device, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To previously prevent unnecessary noise from generating, and temperature of a drive source from excessively rising, by setting a movement control quantity for returning a sensor standbying on a standby position to a reference position smaller than a movement control quantity for previously moving the sensor to the reference position, and enabling an operating time of a sensor driving means to be shortened when the sensor standbying on the standby position is returned to the reference position. SOLUTION: A sensor 47 is previously positioned on a reference position PB, and the sensor 47 is moved from the reference position PB to a standby position PW previously set according to the size of a print paper sheet 26. The sensor 47 is moved from the standby position PW to the print paper sheet 26 carried in the side of the standby position PW so as to detect the side end of the print paper sheet 26, and the sensor 47 is let stand by on the standby position PW until the next print paper sheet 26 is carried in the side of the standby position PW. Accompanying completion of detection of the side end position of the print paper sheet 26, the sensor 47 is returned to the reference position PB. A movement control quantity for returning the sensor 47 standbying on the standby position PW to the reference position Ps is set smaller than a movement control quantity for previously moving the sensor 47 to the reference position PB.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for forming images on both sides of a sheet, or for forming multiple images on one side of a sheet, a sheet conveying apparatus incorporated in the image forming apparatus, and the same. The present invention relates to a seat position detecting method.

[0002]

2. Description of the Related Art In an image forming apparatus that forms images on both sides of a sheet or multiple images on one side of a sheet, an intermediate tray for accommodating sheets having an image formed on one side is usually used. It is provided. After the image forming work on one side is completed, the sheets stacked in the intermediate tray are separated and fed one by one, and the image forming work is performed on the side on which an image is to be formed next.

In order to simplify and downsize the above-mentioned intermediate tray, there has been proposed one in which at least a pair of rollers are used to sandwich a plurality of sheets in an accumulated state. Further, as an intermediate tray using such rollers, a method of accumulating a plurality of sheets by shifting the sheets by a predetermined amount along the conveyance direction has been proposed.

By the way, when images are formed on both sides of a sheet or multiple images are formed on one side of a sheet, when the sheet having the image formed on one side is conveyed from the intermediate tray, Due to the deviation of the sheet along the direction perpendicular to the conveyance direction, the image formed first and the image to be formed next may be misaligned. In order to prevent such a problem, when sending out a sheet from the intermediate tray, the position of the side edge of the sheet is grasped by a sensor, and the lateral shift of the sheet is corrected based on this, or A method has also been proposed in which the relative position between the image formed first and the image to be formed next is appropriately corrected by correcting the image forming position.

Since a method of detecting a sheet position deviation in a direction orthogonal to the sheet conveying direction needs to be performed for each sheet sent from the intermediate tray, it is generally used.
A sensor for detecting the position of the side edge portion of this sheet is made to stand by at the standby position set according to the size of the sheets stacked on the intermediate tray, and the sensor is activated each time the sheet is sent out from the intermediate tray. The sheet is moved from the standby position to the sheet side to detect the position of the side end portion of the sheet. Generally, a pulse motor is adopted as a driving source of the sensor. Further, in order to accurately set the reference position to be the reference with respect to the standby position, the sensor is previously positioned at the reference position before moving the sensor to the standby position, and the sensor is moved from this reference position to the standby position.
When the positions of the side end portions of all the sheets stacked on the intermediate tray have been detected, the sensor is returned to the reference position again.

In order to accurately position the sensor at the reference position, a positioning stopper with which the sensor mechanically abuts is provided at this reference position, and a control pulse more than the control pulse required to move the sensor to the reference position is provided. A method is adopted in which a pulse is applied to a pulse motor to cause a step out of the pulse motor so that the sensor surely contacts the positioning stopper.
According to this method, there is an advantage that a sensor for detecting whether or not the sensor has moved to the reference position is unnecessary.

[0007]

In an image forming apparatus for forming images on both sides of a sheet, or for forming images on one side of a sheet in a multiple manner, a sheet position deviation in a direction orthogonal to the sheet conveying direction is eliminated. For detection, it is effective to position the sensor in contact with a positioning stopper provided at the reference position.

In such a conventional image forming apparatus,
When positioning the sensor at its reference position, the amount of movement that is greater than the maximum movement distance of the sensor for the purpose of positioning certainty, that is, the sheet when the minimum size sheet handled by this image forming apparatus passes the side of the sensor. It is necessary to output to the pulse motor a control pulse that gives a movement amount that is greater than the distance between the side edge of and the reference position.

However, in the method of outputting a control pulse to the pulse motor that always gives a larger movement amount than the maximum movement distance of the sensor when the sensor is positioned at the reference position, the sensor is positioned close to the reference position. In such a case, unnecessary noise is generated and the temperature of the pulse motor is unnecessarily increased, which is one of the causes of shortening the life of the expensive pulse motor.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sheet position detecting method, a sheet conveying apparatus and an image forming apparatus which suppress unnecessary noise and suppress a reduction in the life of a driving source.

[0011]

According to a first aspect of the present invention, a sensor for detecting a position of a side edge of a sheet is preliminarily positioned at a reference position, a step of detecting a size of the sheet, and a sheet The standby position of the sensor according to the size of the sheet, moving the sensor from the reference position to the standby position, and moving the sensor from the standby position to move the sensor from the standby position to the side of the standby position. The step of detecting the position of the side edge of the sheet, and the step of waiting the sensor in the standby position until the next sheet for which the position of the side edge is to be detected is carried into the side of the standby position.
With the step of returning the sensor waiting at the standby position to the reference position upon completion of the detection of the position of the side edge of the sheet, the sensor waits at the standby position more than the movement control amount for moving the sensor to the reference position in advance. A seat position detecting method is characterized in that a movement control amount for returning the inside sensor to the reference position is set small.

A second aspect of the present invention is a sensor for detecting a side edge of a sheet, a sensor driving means for driving the sensor so as to reciprocate in the width direction of the sheet, and the sensor as a reference. A positioning stopper for positioning at a position, a means for detecting the position of the sensor by the sensor driving means, a sheet size detecting means for detecting the size of the sheet, and a sheet size detecting means for detecting the sheet size. Standby position setting means for setting the standby position of the sensor according to size, and drive control for operating the sensor driving means to move the sensor to the reference position, the standby position, and the seat side from the standby position, respectively. The drive control means is a movement control for moving the sensor to the reference position in advance. Than, in the sheet conveying device, characterized in that the sensor waiting at the standby position is set smaller the movement control amount for returning to the reference position.

Further, a third aspect of the present invention is an image forming apparatus having a sheet conveying device, wherein the sheet conveying device includes a sensor for detecting a side edge of the sheet and the sensor for detecting the side edge of the sheet. A sensor driving unit that drives the sensor to reciprocate in the width direction, a positioning stopper that positions the sensor at a reference position, a unit that detects the position of the sensor by the sensor driving unit, and a size of the sheet. Sheet size detecting means, standby position setting means for setting the standby position of the sensor according to the size of the sheet detected by the sheet size detecting means, and the sensor driving means to operate the sensor to the reference position. And a drive control means for moving the standby position and the standby position to the seat side, respectively. Is smaller than the movement control amount for moving the sensor to the reference position in advance, the movement control amount for returning the sensor waiting at the standby position to the reference position is set to be smaller. It is in the image forming apparatus.

Therefore, the drive control means actuates the sensor drive means to bring the sensor for detecting the position of the side edge of the sheet into contact with the positioning stopper to preliminarily position it at the reference position, while the sheet size detection means detects it. The standby position setting means sets the standby position of the sensor in accordance with the size of the sheet, and moves the sensor to this standby position. Then, the sensor is moved from the standby position to the sheet side with respect to the sheet conveyed to the side of the standby position, the position of the side edge of the sheet is detected, and the next sheet is conveyed to the side of the standby position. , This sensor is made to stand by at the waiting position again.

In this way, when the detection of the position of the side edge of the sheet is completed, the sensor waiting at the standby position is returned to the reference position. In this case, the movement control amount for returning the sensor in the standby position to the reference position is set to be smaller than the movement control amount for moving the sensor to the reference position in advance. The time gets shorter.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION In the seat position detecting method according to the present invention, the movement control amount for returning the sensor waiting at the standby position to the reference position is more than the movement control amount for moving the sensor to the reference position in advance. The amount of movement control for moving the sensor to the reference position in advance should be set in correspondence with the distance from the reference position to the side edge of the smallest size sheet. The movement control amount for returning the sensor on standby to the reference position is preferably set in correspondence with the distance from the reference position to the standby position.

Next, in the sheet conveying apparatus according to the present invention, the drive control means for actuating the sensor driving means to move the sensor to the reference position and the standby position and to the sheet side from the standby position respectively sets the sensor to the reference position in advance. The movement control amount for returning the sensor waiting at the standby position to the reference position is set to be smaller than the movement control amount for moving.

On the other hand, in the image forming apparatus of the present invention having this sheet conveying apparatus, the drive control means for actuating the sensor drive means to move the sensor to the reference position, the standby position and the sheet side from the standby position is the sensor. The movement control amount for returning the sensor in the standby position to the reference position is set to be smaller than the movement control amount for moving the sensor to the reference position in advance.

In the above-described sheet conveying apparatus and image forming apparatus, the movement control amount for moving the sensor to the reference position in advance is set corresponding to the distance from the reference position to the side edge of the minimum size sheet. It is preferable that the movement control amount for returning the sensor waiting at the standby position to the reference position is set corresponding to the distance from the reference position to the standby position.

Further, there is further provided a sheet feeding means for feeding the sheets one by one to the side of the sensor at the standby position, and this sheet feeding means stacks a plurality of sheets by shifting them by a predetermined amount along the feeding direction. In this case, the sheet feeding means sends only the first sheet from the plurality of sheets stacked by the stacking means to the side of the sensor and stacks the remaining sheets. It is desirable to return to the means side.

Further, the sensor driving means may have a pulse motor, and the movement control amount may bring the pulse motor out of step.

[0022]

1 to 1 show an embodiment in which a printing apparatus incorporating a sheet conveying apparatus capable of realizing a sheet position detecting method according to the present invention is applied to a two-color digital copying machine.
As will be described in detail with reference to FIG. 4, the present invention can be applied not only to such a two-color digital copying machine, but also to other various office machines and their sheet conveying devices.

As shown in FIG. 1, which shows the schematic structure of the two-color digital copying machine in the present embodiment, one or a plurality of sheet-shaped originals are continuously placed on the original glass 11 and placed on the original glass 11. A document feeding device 12 capable of feeding to a predetermined position on 11 is provided. A scanner 13 is provided directly below the platen glass 11 for scanning and moving from the left side to the right side in FIG. 1 in parallel with the platen glass 11. The scanner 13 includes a document illumination lamp 14 and a reflecting mirror 15. 13 indicates that when a document is placed on the platen glass 11,
The reflected light L _R from the original is imaged on the image sensor 19 by the imaging lens 18 via the reflecting mirrors 16 and 17. The image data of the original taken in by the image sensor 19 is sent to the image signal control unit 20, and the exposure control unit 21 which is a laser scanner uses the light beam based on the image data processed by the image signal control unit 20. L
_B is modulated and the photosensitive drum 22 is scanned and exposed to form an electrostatic latent image corresponding to image data on the surface of the photosensitive drum 22.

In the figure, a charger 2 for uniformly charging the surface of the photoconductor drum 22 is arranged around the photoconductor drum 22 which is driven to rotate clockwise, in order from the upstream side in the rotation direction.
3, two developing devices 24 and 25 that can alternately approach the photoconductor drum 22, a transfer device 27 for transferring the developed toner image to a print paper 26 as a sheet of the present invention, and a photosensitive device. A separator 28 for separating the print paper 26 from the body drum 22 and a cleaning unit 29 for removing the toner remaining on the surface of the photosensitive drum 22 are provided. Developers of different colors are stored.

The print papers 26 of different sizes housed in the paper cassettes 30 and 31, respectively, are adjusted one by one from the paper guide 32 by the timing roller 33 so that the transfer timing is adjusted between the transfer device 27 and the photosensitive drum 22. When the toner image is supplied, the toner image is transferred to the conveyor belt 34.
And is conveyed between the pair of fixing rollers 35. Then, the toner image on the print paper 26 is heat-fixed by the pair of fixing rollers 35, and in the case of one-sided copying, the toner image is sent from the carrying roller 36 through the discharging roller 37 to a paper discharging tray (not shown).

In the case of multiple copying, the print paper 2 after fixing
The conveyance direction of 6 is switched by the flapper 38 from the conveyance roller 36, further conveyed by the supply roller 39 and fed to the circulation conveyance path 40. This circulating transport path 4
At 0, the print paper 26 is sent to the intermediate tray 42 via the forward / reverse rotation roller 41, and the print paper 26 is temporarily stopped in the intermediate tray 42 and enters the standby state. Then, the print sheets 26 waiting on the intermediate tray 42
Is transported to the timing roller 33 by the delivery roller 43 and the delivery roller 44 based on a paper feed signal from a microprocessor (not shown) for controlling the apparatus body. Then, after that, a multiple image is formed on the print paper 26 through the same process as described above.

In the case of double-sided copying, the print paper 2 after fixing
6 is temporarily carried out to the discharge tray side (not shown) by the preceding discharge roller 37, and then the discharge roller 37 is reversely rotated to be guided to the flapper 38 and fed into the circulation conveyance path 40. Then, the print paper 26 is reversed, and then a copy is made on the surface on the side where the image is not formed.

On the other hand, on the upper surface of the two-color digital copying machine, an operation panel for making various settings such as editing and copying is arranged, and switches and various keys described below are arranged on this operation panel. .

That is, 71 is a power switch for controlling the energization of the image signal controller 20. Reference numeral 72 denotes a reset key, which operates as a key for returning the settings of various modes to the standard mode during standby. Reference numeral 73 is a copy start key. A clear key 74 is used when clearing the set numerical value. Reference numeral 75 denotes an ID key. This ID key 75 enables the copying operation of only a specific operator.
The copy operation can be prohibited unless is input. A stop key 76 is used when the copying operation is interrupted or stopped. 77 is a guide key,
It is used when you want to know the contents of various functions. 78a, 78
b, 78c, 78d are cursor keys for up, down, left and right,
This is for moving the pointer vertically and horizontally on each function setting screen. 79 is an OK key,
This is for confirming each function setting screen. Reference numeral 80 denotes a function execution key for executing the contents displayed on the display 89 described later on each function setting screen. 81a
Is a standard size reduction key, and is used when reducing from one standard size to another standard size. Reference numeral 81b is a same size copy key, which is used when selecting the same size copy. Reference numeral 81c is a standard enlargement key, which is used to enlarge from one standard size to another standard size. Reference numeral 82 denotes a cassette selection key, which is a paper cassette 3 for the print paper 26 to be copied.
Select 0, 31. Reference numeral 83a denotes a copy density selection key, which is used to reduce the copying machine speed. 83b is AE
This is a key that automatically adjusts the copy density with respect to the original density. Reference numeral 83c denotes a copy density selection key, which is used to increase the copy density. Reference numeral 84 is a sorter key for designating the operation mode of the sorter. A residual heat key 85 is used to switch the residual heat mode on / off. Reference numeral 86 denotes an interrupt key, which is used when interrupting during copying and copying is desired. A numeral pad 87 is used when inputting a numerical value.

Reference numeral 88 is a group of various editing keys, each of which has the following functions. That is, for trimming, masking, partial processing (contour, mesh, shadow, negative / positive) settings, for color pattern expression or color density difference expression, for erasing specific colors, for setting image quality, for inverting negative / positive, For contour, shadow, mesh, italic, mirror image, image repeat processing, area-specified trimming, area-specified masking, area-specified partial processing (contour, mesh, shadow, negative-positive, etc.) settings , Create a blank frame to fit the sheet size Erase the sheet frame, Create a blank frame to fit the specified document size Erase document border, Blank frame and center to fit the specified spread size of the book Blank areas for creating blank areas for book erasing in accordance with various erasing modes, for binding margins created at one end of the print paper 26, up / down / left / right parallel movement, center movement, corner movement, designated movement (port The main scanning and sub-scanning independently, and for setting the copy magnification (25% to 410%) in increments of 1%, the main scanning and sub-scanning are automatically enlarged independently according to the sheet size. For reduction, copying for expanding originals to multiple sheets, copying for expanding or reducing two or four originals to one, dividing the copy area on the platen glass surface into two, and automatically copying to two For continuous copying, single-sided / double-sided, page continuous / double-sided, double-sided / double-sided output, multiplex, page continuous multiplex / multiplexing, memory card, projector, printer setting, feeder This is for performing various editing operations such as for mixed original size when copying using, for registering a copy mode for which copying is set, or for calling a registered copy mode.

Reference numeral 89 is a display, which indicates the state of the device,
The number of copies, the copy magnification, and the size of the print paper 26 are displayed, and the set contents are displayed while the copy mode is being set. A system residual heat key 90 is used to turn on / off a system residual heat mode in which only an external interface (not shown) and its peripheral circuits are operated, and a control unit for copying is stopped. Reference numeral 91 denotes a power display unit, which is turned on when the power switch 71 is in the on state and turned off when the power switch 71 is in the off state.

As shown in FIG. 3 which is an enlarged view of the circulation conveyance path 40 in this embodiment, the intermediate tray 42 between the forward / reverse rotation roller and the delivery roller 43 is rotated in synchronization with the forward / reverse rotation roller 41. A pair of auxiliary rollers 45 that can sandwich the print paper 26 is provided, and between the auxiliary rollers 45 and the feed roller 43, only the earliest print paper 26 is separated from the stacked print paper 26. A separation flapper 46 that guides to the delivery roller 43 side is rotatably provided. In addition, the delivery roller 43
A sensor 47 for grasping the position of the side end of the print paper 26 carried out to the photoconductor drum 22 side is provided in the middle of the conveyance path of the print paper 26 between the discharge roller 44 and the carry-out roller 44.

The sensor 47 reciprocates between a preset reference position P _{B as} shown in FIG. 4 and a side end portion of the print paper 26 to grasp the relative position of the print paper 26 with respect to the reference position P _B. By doing so, the copy area on the print paper 26 is appropriately corrected, and the appearance of the sensor 47 at the reference position P _B is shown in FIG.
6 and its control block is shown in FIG.

That is, the sensor 47 is reciprocally movable in the direction perpendicular to the conveying direction of the print paper 26 via the guide mechanism 48, that is, in the width direction of the print paper 26 (left and right direction in FIG. 4). And this slider 49
A detection lever 50 having a base end rotatably pivotally attached to one end side of the sheet and a front end side urged to a side end side of the print sheet 26;
The detection element 51 is provided on the other end side of the slider 49 and detects the presence or absence of the tip of the detection lever 50. And
By the operation of the pulse motor 53 based on the command from the pulse motor control device 52, the slider 49 moves toward the side end of the print paper 26 while being guided by the guide mechanism 48, and the tip of the detection lever 50 moves the print paper 26. As shown in FIG. 7 which shows the detection state of the side end portion of the print sheet 26 by being abutted against the side end portion and pushed back toward the detection element 51 side, the pulse motor 53 of the pulse motor 53 in the state where the detection lever 50 closes the detection element 51. The movement amount is grasped by the pulse motor control device 52.

The pulse motor controller 52 receives a detection signal from a sheet size detector 54 for detecting the size of the print sheets 26 stacked in the intermediate tray 42, and the pulse motor controller 52 detects the sheet size. The standby position P of the sensor 47 based on the information from the device 54
_W is set, and the sensor 47 is moved from the reference position P _B to the standby position P _W. Standby position P
_W is positioned between the passing position of the side end portion of the reference position P _B and the print paper 26, the position where the print sheet 26 is expected to pass through the most reference position P _B close, somewhat reference position P _B It is set to the side by the pulse motor control device 52. A positioning block 55 that abuts the slider 49 is provided at the reference position P _B , and the slider 49 is abutted on the positioning block 55 so that the sensor 47 is always accurately positioned at the reference position P _B. be able to.

Specifically, when the power switch 71 is turned on, the distance between the side end of the smallest size print paper 26 handled by this two-color digital copying machine and the reference position P _B , that is, the maximum movement of the sensor 47. A drive pulse larger than the distance (hereinafter, referred to as a maximum drive pulse) is applied to the pulse motor 53 so that the slider 49 of the sensor 47 can be reliably positioned on the positioning block 55 wherever the sensor 47 is located on the guide mechanism 48. To the sensor 47 with respect to the reference position P _B by depressing the pulse motor 53.
Is positioned. Further, when returning the sensor 47 from the standby position P _W to the reference position P _B , more drive pulses than the drive pulses corresponding to the interval between the standby position P _W and the reference position P _B (hereinafter, this is restored). Although described as a drive pulse), it is needless to say that this return drive pulse has a smaller control amount than the maximum drive pulse.

Next, the procedure for conveying the print paper 26 when performing multiplex copying or double-sided copying will be described in detail with reference to FIGS.

When the print sheet 26 having an image formed on one side is sent to the supply roller 39, the print sheet 26
In order to pull out the rear end from the supply roller 39, the print sheet 26 is sandwiched by the forward / reverse rotation roller 41, and then the forward end of the print sheet 26 is pulled out from the forward / reverse rotation roller 41 by a preset distance P _0. The reverse rotation roller 41 is rotated (see FIG. 8).

After that, the forward / reverse rotation roller 41 is reversely rotated so that the front end of the print paper 26 comes to a predetermined distance (hereinafter referred to as a stacking interval) P from the forward / reverse rotation roller 41. At this time, the trailing edge of the print paper 26 enters the temporary storage area 56 set below the supply roller 39 (see FIG. 9).

Further, it is judged whether or not the set number of sheets have been stacked, and if the set number has not been reached, for example, when the second print sheet 26 is conveyed and reaches the forward / reverse roller 41, the forward / reverse roller is reached. 41 performs the same operation as the previous time with the first sheet of print paper 26 being sandwiched, and the leading edge of the second sheet of print paper 26 has a stacking interval P from the leading edge of the first sheet of paper.
Stack them with a gap. By repeating this operation from the second sheet onward, it is possible to stack the print papers 26 in a state in which they are sequentially shifted by the stacking interval P as shown in FIG.

In this way, after a predetermined number of print sheets 26 are stacked on the forward / reverse rotation roller 41, they are conveyed to the separation flapper 46 by using the auxiliary roller 45 which rotates in synchronization with the forward / reverse rotation roller 41. First printed sheet 2 loaded
Predetermined distance from the tip of 6 the auxiliary roller 45 (hereinafter, the flapper mounted distance described) when it reaches the P _R, the reverse rotation roller 41 and the auxiliary roller 45 is stopped, showing the separation flapper 46 in FIG. 11 Lower to separation position. At this time, the lower end of the separation flapper 46 is the frontmost print sheet 2
6 and the second print sheet 2 stacked on top of it
The flapper mounting distance P _R is set so that the flapper mounting distance P _R comes into contact with the frontmost surface of the print paper 26 between the front end and the front end of the paper 6.

With the separation flapper 46 in the separation position, only the frontmost print sheet 26 is nipped by the feed roller 43, and the forward / reverse rotation roller 41 and the auxiliary roller 45 are rotated until the rear end is pulled out from the auxiliary roller 45. Let With this feeding operation, the second and subsequent print sheets 26 are separated from each other by the separation guide surface 57 of the separation flapper 46.
Go up (see Figure 12).

The first printing paper 26 is the auxiliary roller 45.
When it is pulled out of the stack, the forward / reverse rotation roller 41 and the auxiliary roller 45 are rotated in the reverse direction so that the leading edge of the newest print paper 26 is positioned closer to the auxiliary roller 45 than the flapper mounting distance P _R. The gap between the leading edge of the print paper 26 and the leading edge of the separation flapper 46 is increased to allow the separation flapper 4
6 so that it can return to the standby position indicated by the chain double-dashed line in FIG. 11 without any problem. The separation flapper 46 sends out the first print sheet 26 in the stacking state and sends out the roller 43.
Each time the sheet is conveyed to, the print sheet 26 is returned to the standby position, and the set number of print sheets 26 of the second and subsequent print sheets 26 are separated one by one and conveyed to the feed roller 43.

In this way, the positions of the side edges of the print sheets 26 fed out from the feed-out roller 43 to the carry-out roller 44 side one by one are confirmed by the sensor 47 during the conveyance. In this case, in order to prevent erroneous determination due to skew of the print paper 26, the carry-out roller 44 is used to form a loop of the print paper 26. After a lapse of a predetermined time required to adjust the leading end position of the print paper 26, the carry-out roller 44 is rotated to convey the print paper 26, and then the sensor 47 in the standby position starts to move.

The operation procedure of the sensor 47 and the flow of its processing are shown in FIGS. 13 and 14. That is, when the power switch 71 is turned on, the position of the sensor 47 on the guide mechanism 48 is indefinite. Therefore, in step S11, the maximum drive pulse is applied to the pulse motor 53 to cause step out, and the slider of the sensor 47 is moved. 49 for positioning block 55
The sensor 47 is positioned at the reference position P _B by being pressed against (the state (A) in FIG. 13).

Next, in step S12, the pulse motor control device 52 reads the sheet size information from the sheet size detecting device 54, and according to the size of the print paper 26 stacked on the intermediate tray 42 in step S13. The standby position P _W is set. Then, in step S14, a drive pulse corresponding to the distance from the reference position P _B to the standby position P _{W is applied} to the pulse motor 53 to move the sensor 47 from the reference position P _B to the standby position P _W (see FIG. 13). ,
(State (B)), and the sensor 47 is made to stand by at this standby position P _W (state (C) in FIG. 13).

Next, in step S15, it is determined whether or not the copying work is completed. However, since it is not completed at first, the process proceeds to step S16, and the carry-out roller 44 is executed here.
It is determined whether or not the drive rotation has started. This S16
If it is determined in step S15 that the carry-out roller 44 is not rotating, that is, the carry-out roller 44 has not finished adjusting the leading end position of the print sheet 26, the process proceeds to S15.
Then, the process returns to the step and the standby state is substantially continued.

When it is determined in step S16 that the carry-out roller has begun to rotate, that is, the supply of the print paper 26 to the timing roller 33 side has started,
In step S17, the pulse motor 53 is driven to move the sensor 47 to the side edge side of the print sheet 26 (state (D) in FIG. 13), and the sensor 47 moves the side edge position of the print sheet 26. The drive pulse is counted until it is detected.

Then, in step S18, the sensor 47
Determines whether the side edge of the print paper 26 is detected,
If it is determined that the sensor 47 has not detected the side edge of the print paper 26, the process returns to step S17 to continue driving the pulse motor 53. If it is determined in step S18 that the sensor 47 has detected the side edge of the print sheet 26, the pulse motor 53 is supplied with a reverse drive pulse equal to the counted drive pulse in step S19. , The sensor 47 again to the standby position P _W
Then, to prepare for the detection of the side edge of the next print sheet 26 (state (E) in FIG. 13), the process returns to step S15.

In this way, the positions of the side edges of the print papers 26 stacked on the intermediate tray 42 are detected one after another to correct the position of each print paper 26 itself and the image writing position, thereby performing the multiple copying. Alternatively, double-sided copying can be appropriately performed. When it is determined in step S15 that the copying operation has been completed, a return drive pulse is applied to the pulse motor 53 to cause step out, and the standby sensor 47 is moved from the standby position P _W to the reference position P _B. After returning (state (F) in FIG. 13), the sensor 47 is pressed against the positioning block 55 to position it.

In this case, since the return drive pulse is smaller than the previous maximum drive pulse, it is possible to prevent the generation of unnecessary noise and the transient temperature rise of the pulse motor 53, thus extending the life of the pulse motor 53. be able to.

Although the positioning block 55 in the fixed state is adopted in the above-mentioned embodiment, it may be movable. Further, the standby position P _W is changed according to the size of the print paper 26 being conveyed.
It is possible to set a common standby position P _W for a plurality of print sheets 26, and even for print sheets 26 of the same size, the first standby position P _W and the second and subsequent standby positions P _W You may try to change and.

[0053]

According to the present invention, the movement control amount for returning the sensor waiting at the standby position to the reference position is set smaller than the movement control amount for moving the sensor to the reference position in advance. When the sensor waiting at the position is returned to the reference position, the operating time of the sensor drive means can be shortened, and unnecessary noise generation and transient temperature rise of the drive source can be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic structure of an embodiment in which an image forming apparatus according to the present invention is applied to a two-color digital copying machine.

FIG. 2 is a plan view of an operation panel of the two-color digital copying machine shown in FIG.

FIG. 3 is a conceptual diagram in which a portion of a circulating conveyance path in the embodiment shown in FIG. 1 is extracted.

FIG. 4 is a plan view of a portion of the sensor in the embodiment shown in FIG.

5 is a plan view of the sensor at the reference position in the embodiment shown in FIG.

FIG. 6 is a control block diagram in the embodiment shown in FIG.

FIG. 7 is a plan view showing a state in which a side edge position of print paper is detected by the sensor in the embodiment shown in FIG.

FIG. 8 is a work process diagram showing a print paper stacking procedure in the embodiment shown in FIG. 1 together with FIGS. 9 and 10;

9 is a work process diagram showing a procedure for stacking print sheets in the embodiment shown in FIG. 1 together with FIG. 8 and FIG.

10 is a work process diagram showing a procedure for stacking print sheets in the embodiment shown in FIG. 1 together with FIG. 8 and FIG.

11 is a work process diagram showing a work procedure for separating one print sheet from the stacked print sheets in the embodiment shown in FIG. 1 together with FIG.

12 is a work process diagram showing a work procedure for separating one print sheet from the stacked print sheets in the embodiment shown in FIG. 1 together with FIG.

13A and 13B are operation process diagrams sequentially showing the movement path of the sensor in the embodiment shown in FIG.

FIG. 14 is a flowchart showing a flow of operations in the embodiment shown in FIG.

[Explanation of reference numerals] 11 original platen glass 12 original feeding device 13 scanner 14 original illumination lamp 15 to 17 reflecting mirror 18 imaging lens 19 image sensor 20 image signal control unit 21 exposure control unit 22 photoconductor drum 23 charger 24, 25 Developing Device 26 Printing Paper 27 Transfer Device 28 Separator 29 Cleaning Section 30, 31 Paper Cassette 32 Paper Guide 33 Timing Roller 34 Conveying Belt 35 Fixing Roller 36 Conveying Roller 37 Ejecting Roller 38 Flapper 39 Supplying Roller 40 Circulating Conveying Path 41 Forward / Reverse Roller 42 Intermediate tray 43 Delivery roller 44 Delivery roller 45 Auxiliary roller 46 Separation flapper 47 Sensor 48 Guide mechanism 49 Slider 50 Detection lever 51 Detector 52 Pulse motor control device 53 Pulse motor 54 Sheet size detection device 55 Positioning Block 56 Temporary Storage Area 57 Separation Guide Surface 71 Power Switch 72 Reset Key 73 Copy Start Key 74 Clear Key 75 ID Key 76 Stop Key 77 Guide Keys 78a to 78d Cursor Keys 79 OK Key 80 Function Execution Key 81a Standard Reduction Key 81b Same size copy key 81c Standard enlargement key 82 Cassette selection key 83a Copy density selection key 83b AE key 83c Copy density selection key 84 Sorter key 85 Remaining heat key 86 Interrupt key 87 Numeric keypad group 88 Editing key group 89 Display 90 System remaining heat key 91 Power display section L _R reflected light L _B light beam P _B reference position P _W standby position P ₀ preset distance P loading interval P _R flapper mounting distance

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location G03G 15/00 510 G03G 15/00 510

Claims (15)

[Claims] 1. A step of previously positioning a sensor for detecting a position of a side edge of a sheet at a reference position, a step of detecting a size of the sheet, and a step of setting a standby position of the sensor according to the size of the sheet. The step of moving the sensor from the reference position to the standby position, the step of moving the sensor from the standby position to detect the position of the side edge of the sheet with respect to the sheet conveyed to the side of the standby position, and the side edge. The step of waiting the sensor at the standby position until the next sheet to be detected is conveyed to the side of the standby position, and the sensor waiting at the standby position when the detection of the position of the side edge of the sheet is completed. The step of returning the sensor in the standby position to the reference position more than the movement control amount for moving the sensor to the reference position in advance. A seat position detecting method characterized in that the dynamic control amount is set to be small. 2. The movement control amount for moving the sensor to the reference position in advance is set according to the distance from the reference position to the side edge of the minimum size sheet. The seat position detection method described in. 3. The movement control amount for returning the sensor waiting at the standby position to the reference position is set according to the distance from the reference position to the standby position. The sheet position detection method according to Item 2. 4. A sensor for detecting a side edge of a sheet, a sensor driving unit for driving the sensor so as to reciprocate in the width direction of the sheet, and a positioning stopper for positioning the sensor at a reference position. A means for detecting the position of the sensor by the sensor driving means, a sheet size detecting means for detecting the size of the sheet, and a standby position of the sensor according to the size of the sheet detected by the sheet size detecting means And a drive control means for operating the sensor drive means to move the sensor to the reference position, the standby position, and the seat side from the standby position, respectively. Stands by at the standby position rather than the movement control amount for moving the sensor to the reference position in advance. A sheet conveyance device, wherein a movement control amount for returning the inside sensor to the reference position is set small. 5. A movement control amount for moving the sensor to the reference position in advance is set in correspondence with a distance from the reference position to a side end portion of the sheet of the minimum size. The sheet conveying device according to claim 4. 6. The movement control amount for returning the sensor waiting at the standby position to the reference position is set according to the distance from the reference position to the standby position. Item 5. The sheet conveying device according to item 5. 7. A sheet feeding means for feeding the sheets one by one to the side of the sensor at the standby position, wherein the sheet feeding means feeds a plurality of sheets by a predetermined amount along the feeding direction. The sheet conveying device according to claim 4, further comprising a stacking unit that stacks the sheets in a shifted manner. 8. The sheet according to claim 7, wherein the sheet supply unit feeds the first sheet to the side of the sensor from a plurality of sheets stacked by the stacking unit. Transport device. 9. The method according to claim 4, wherein the sensor driving means has a pulse motor, and the movement control amount causes a step out of the pulse motor.
The sheet conveying apparatus according to any one of 1. 10. An image forming apparatus having a sheet conveying device, wherein the sheet conveying device drives a sensor for detecting a side edge of the sheet and the sensor so as to be capable of reciprocating in the width direction of the sheet. Sensor driving means, a positioning stopper for positioning the sensor at a reference position, and means for detecting the position of the sensor by the sensor driving means,
A sheet size detection unit that detects the size of the sheet, a standby position setting unit that sets the standby position of the sensor according to the size of the sheet detected by the sheet size detection unit, and the sensor driving unit are operated. And a drive control means for moving the sensor to the reference position, the standby position, and the seat side from the standby position, respectively.The drive control means is a movement control amount for moving the sensor to the reference position in advance. The image forming apparatus is characterized in that the movement control amount for returning the sensor in the standby position to the reference position is set to be smaller than that in the standby position. 11. A movement control amount for moving the sensor to the reference position in advance is set corresponding to a distance from the reference position to a side edge portion of the sheet of the minimum size. The image forming apparatus according to claim 10. 12. The method according to claim 10, wherein the movement control amount for returning the sensor waiting at the standby position to the reference position is set corresponding to the distance from the reference position to the standby position. Item 12. The image forming apparatus according to Item 11. 13. The apparatus further comprises sheet feeding means for feeding the sheets one by one to the side of the sensor at the standby position, and the sheet feeding means feeds a plurality of sheets by a predetermined amount along the feeding direction. The image forming apparatus according to any one of claims 10 to 12, further comprising a stacking unit that shifts and stacks the stacking unit. 14. The image according to claim 13, wherein the sheet supply unit feeds the first sheet to the side of the sensor from a plurality of sheets stacked by the stacking unit. Forming equipment. 15. The sensor driving means has a pulse motor, and the movement control amount causes a step out of the pulse motor, according to any one of claims 10 to 14. Image forming device.