JPS61275772A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent a material to which an image is transferred from shifting in position laterally by detecting the lateral position shift of a form and storing it in a memory and correcting an image formation position according to the difference from the quantity of a position shift when a form is supplied again. CONSTITUTION:A form is fed to a transfer part and the 1st original detector 130 detects the quantity Ix1 of the lateral shift of the form. This quantity Ix1 is stored in the memory 137. Then, the form is supplied to the transfer part again. At this time, the quantity Ix2 of th lateral shift of the form is detected by the detector 130 and subtracted from the quantity Ix1 stored in the memory 137 to calculate an error Ex=Ix1-Ix2. Then, a lens block for displacement is operated on the basis of the error Ex to move the formation position of an image corresponding to the lateral position of the form. Consequently, the image having high quality is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image forming apparatus applied to, for example, an electronic copying machine.

[Technical background of the invention and its problems]

As is well known, in conventional copying machines, duplex copying devices that form images on both sides of paper, multiple copying devices that perform multiple copies on one side of paper, or devices that have both of these functions have been developed. .

Incidentally, in both of these double-sided copying devices and multiple copying devices, a sheet of paper that has been copied once is conveyed again to a transfer section. For this reason, if the conveyance path is long or there is a stacking section that stores paper in the middle of the conveyance path, the paper may shift horizontally and when fed to the transfer section again, it will not match its original position. Sometimes. Particularly when performing multiple copies, there is a problem in that the occurrence of such positional deviations greatly impairs copy quality.

[Purpose of the invention]

This invention was made based on the above circumstances,
The purpose is to provide an image forming apparatus that can prevent lateral displacement of a transfer material and can form high-quality images.

[Summary of the invention]

For example, this invention provides an optical detector near the registration roller, detects the amount of paper misalignment in the lateral direction, and stores the amount of paper misalignment detected by this detector in a memory, so as to perform multiple copying, etc. The variable magnification lens block is moved according to the error between the positional deviation amount when the paper is supplied to the transfer unit again and the stored positional deviation amount, and an image is formed on the paper on which an image has already been formed. This is to correct the position.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 4 and 5 schematically show an image forming apparatus, such as a copying machine, according to the present invention. That is, 1 is a main body of a copying machine, and a document table (transparent glass) 2 is fixed to the upper surface of the main body 1 to support a document. This document table 2 is provided with a fixed scale 21 that serves as a reference for setting the document, and roughly in the vicinity of the document table 2 is provided a document cover 11 that can be opened and closed and a work table 12. The original placed on the original table 2 is exposed to an exposure lamp 4, a mirror 5.
6. The optical system consisting of
By reciprocating in the direction, exposure scanning is performed during the reciprocating movement. In this case, mirror 6.7 moves at half the speed of mirror 5 so as to maintain the optical exposure length. The light reflected from the original by the scanning of the optical system, that is, the light reflected from the original by the light irradiation of the exposure lamp 4, is reflected by the mirror 5.6.7, passes through the variable magnification lens block 8, and then passes through the mirror 9r. , 92, 93 and guided to the photosensitive drum 10, so that an image of the document is formed on the surface of the photosensitive drum 10.

The photoreceptor drum 10 rotates in the direction of arrow C in the figure, and its surface is first charged by a charging device 11, and then an image is exposed to slit light to form an electrostatic latent image on its surface. This electrostatic latent image is visualized by adhering the toner to it by developing devices 121 and 122 which each contain red or black toner and are selectively operated as required. There is.

On the other hand, the paper (transferring material) P is delivered from the selected upper paper feed cassette 131, middle paper feed cassette 132, or lower paper feed cassette 133 to the feed rollers 141, 142, 14.
g and roller pair 1511152.153 to take out the sheets one by one, and the paper guide path 161.162.16! The image is guided through the image to a pair of registration rollers 17, and guided to a transfer section by the pair of registration rollers 17. Here, the above paper feed cassette 131, 132, 133
is removably provided at the lower right end of the main body 1,
Either one can be selected on the operation panel described later. In addition, each of the above paper feed cassettes 13. r
, 132, and 133 are such that the cassette size is detected by cassette size detection switches 60s and 602, and 603, respectively. The cassette size detection switches 601, 602, and 60g are composed of a plurality of microswitches that are turned on and off according to the insertion of cassettes of different sizes.

The paper P sent to the transfer section comes into close contact with the surface of the photoreceptor drum 10 at the transfer charger 18, so that the toner image on the photoreceptor drum 10 is transferred by the action of the charger 18. . This transferred paper P is transferred to the peeling charger 1
9, it is electrostatically peeled off from the photosensitive drum 10 and conveyed by the conveyor belt 20, and sent to the fixing roller 21 as a fixing device provided at the end of the conveyor belt. It will be established. Then, paper P after fixing
The sheets are delivered to a tray 25 outside the main body 1 by a pair of delivery rollers 22, a sorting gate 23 operated as shown by the solid line, and a pair of discharge rollers 24. Further, after the photosensitive drum 10 has been transferred, residual toner on the surface is removed by a cleaner 26, and afterimages are erased by a static elimination lamp 27, so that the photosensitive drum 10 returns to its initial state. In addition,
29 is a cooling fan for preventing the temperature inside the main body 1 from rising.

On the other hand, a double-sided multiple copying unit 28 is provided below the copying machine main body 1, which enables double-sided copying on one sheet of paper or multiple copies on the same side. This unit 28 includes a gate 23 for the above-mentioned sorting, a pair of paper ejection rollers 2
4, the sorting is performed by a plurality of roller pairs 28b that guide the sheets taken in by the gate 23 to the stacking section 28a.
128C128d is provided. Further, the stacking section 28a is provided with a delivery row 528e for sending out the paper temporarily stored in the stacking section 28a. This delivery roller 28e can move up and down as shown by the arrow in the figure, depending on the thickness (number of sheets) of the stored paper. The paper sent out by the delivery roller 28e passes through a separation roller pair 28f that separates the paper sheets one by one and sends them out to the control gate 28Q.
will be guided to. When performing multiple copying, the control gate 28G is rotated in the direction of the arrow M shown in the figure, and guides the paper to the registration roller pair 17 via the transport roller pair 28h1 and the paper guide path 28i.

Further, when double-sided copying is to be performed, the state shown in the figure is first set, and the paper is guided to the reversing section 28 via a pair of conveying rollers 28J. When the paper is stored in the reversing section 28k, the control gate 28Q is rotated in the direction of arrow T in the figure, and the paper sent by the pair of transport rollers 28j is transferred to the pair of transport rollers 28.
h, the registration roller pair 1 via the paper guide path 281;
7.

FIG. 6 shows the operation panel 30 provided on the main body 1. 30i is a copy key for commanding the start of copying, 302
is a numeric keypad for setting the number of copies, etc., 303 is a display section that displays the operating status of each part and paper jams, etc.; 304 is a cassette selection key for selecting the upper and lower paper feed cassettes 13s, 132 and 133; 30! i is a cassette display section for displaying the selected cassette; 30s is a magnification setting key for setting the enlargement and reduction magnification of copies in a predetermined relationship; 307 is a zoom key for steplessly setting the enlargement and reduction magnification; 30a is a set 30 is a display section for displaying the magnification, 30 is a density setting section for setting copy density, 30a is a multiple copy setting key, 30
b is a double-sided copy setting key; 30c is a red designation key that designates, for example, the developing device 121 containing red toner; and 30d is a black designation key that designates, for example, the developing device 122 that contains black toner.

FIG. 7 shows an example of the configuration of the drive source for each drive section of the copying machine configured as described above, and is composed of the following motors. That is, 31 is a lens motor, which is a motor for moving the position of the lens block 8 for changing the magnification.

32 is a mirror motor, which is a motor for changing the distance (optical path length) between the mirror 5 and the mirror 6.7 for changing the magnification. 33 is a scanning motor, which connects the exposure lamp 4, the mirror 5, and the mirror 6.
．． This is a motor for moving 7 for document scanning. 34 is a shutter motor, which is a motor for moving a shutter (not shown) for adjusting the charging width of the photosensitive drum 1o by the charger 11 during zooming. 35r and 352 are developing motors, respectively, and are motors for driving the developing rollers of the developing units 121 and 122. 36 is a drum motor, which is a motor for driving the photosensitive drum 10. 37
A fixing motor is a motor for driving the paper conveyance path 20 and the pair of fixing rollers 21. 38 is a paper feeding motor, and the feed rollers 141 to 143, 151
This is a motor for driving 153. Reference numeral 39 denotes a paper feed motor, which is a motor for driving the registration roller pair 17. 40 is a fan motor for driving the cooling fan 29, and 401 is a pair of rollers 24.28b.

This is a motor for driving 28c, 28d, etc.

FIG. 8 shows a drive structure for reciprocating the optical system. That is, the mirror 5 and the exposure lamp 4 are supported by a first carriage 411, and the mirror 6.7 is supported by a second carriage 422, respectively, and these carriages 411 and 412 are guided by guide rails 421 and 422 in the direction of arrow a. It can be moved in parallel. That is,
A four-phase pulse motor 33 drives a pulley 43. An endless belt 4 is connected between this pulley 43 and the idler pulley 44.
5 is stretched around the belt 45, and one end of a first carriage 411 that supports the mirror 5 is fixed to the middle part of the belt 45. On the other hand, the second carriage 4 supporting the mirror 6.7
Two pulleys 47.47 are rotatably provided on the guide portion 46 of the rail 422 and spaced apart in the axial direction of the rail 422, and a wire 48 is wound around these pulleys 47.47.

One end of this wire 48 is fixed to a fixed part 49, and the other end is fixed to the fixed part 49 via a coil spring 50. Further, one end of a first carriage 411 is fixed to a midway portion of the wire 48. Therefore, as the pulse motor 33 rotates, the belt 45 rotates, the first carriage 411 moves, and the second carriage 422 also moves accordingly. At this time, since the pulleys 47, 47 serve as movable pulleys, the second carriage 422 moves in the same direction as the first carriage 411 at 1/2 the speed. In addition, the first and second carriages 41
The moving direction of 1.412 is controlled by switching the rotation direction of the pulse motor 33.

Further, on the document table 2, a copyable range corresponding to the specified paper is displayed. That is, the paper selection key 304
If the paper size specified by is (PX, PV') and the copy magnification specified by the magnification setting keys 306 and 307 is K, then the copyable range (x, y), rx-P
x/KJ.

ry-Py/K". This copyable range (x, y)
In the X direction, a pointer 51 provided on the back side of the document table 2
．． 52, and the y direction is indicated by a scale 53 provided on the upper surface of the first carriage 411.

As shown in FIG. 9, the above-mentioned pointers 51 and 52
．． 55 via a spring 56. The pulley 55 is a motor 58
This motor 58
The distance between the hands 51 and 52 can be changed by rotating the hands according to the paper size and magnification.

Further, the first carriage 411 is moved to a predetermined position (home position according to the magnification) by driving the motor 33 according to the paper size and magnification. Then, when the copy key 30s is pressed, the first
The carriage 411 is first moved toward the second carriage 412, and then the lamp 4 is turned on and the carriage 411 is moved away from the second carriage 412. When scanning of the original is completed, the lamp 4 is turned off and the first carriage 411
is returned to the home position.

FIG. 10 shows a drive mechanism for the variable magnification lens block 8. As shown in FIG. The motor 31 is connected to a first carriage 411
A lead screw 61 arranged along the moving direction (y direction) is rotated. A bush 6311632 provided at one end of the substrate 62 is screwed into the lead screw 61, and when the lead screw 61 is rotated, the substrate 62 is moved in the y direction.

A guide member 621 is provided at the other end of the substrate 62, and the guide member 621 is vibably engaged with the guide rail 64. Further, the substrate 62 includes a substrate 62 .
A movable body 65 is provided, which is movable in a direction (X direction) orthogonal to the image plane and has the magnification changing lens block 8 under control. That is, supports 65z are provided at both ends of the moving body 65.
, 652 are provided, and this support 651.652
are guided and held by guide members 661 and 662 provided on the substrate 62. Further, a rack 653 is provided on the longitudinal and opposite side surfaces of the support body 651, and a pinion 68 rotated by a pulse motor 67 provided on the base plate 62 is meshed with this rack 653. Therefore, the lens block 8 for variable magnification is controlled by the motor 6.
7 is driven, it is moved in the X direction. Note that the microswitches 691 and 692 are for detecting the initial positions of the substrate 62 and the moving body 65, respectively.

Next, the relationship between the operation of the variable magnification lens block 8 and the image formed will be explained. In FIG. 11(a), the focal length of the variable power lens block 8 is f, the optical path length from the document table 2 to the variable power lens block 8 is ya, and from the variable power lens block 8 to the photosensitive drum 10. When the optical path length is yb1 and the total optical path length from the document table 2 to the photosensitive drum 10 is yc, the optical formula is expressed as follows.

1/f-1/Va+1/Vb Also, the magnification is expressed as yb/ya. Since the focal length f of the variable power lens block 8 is constant, it is understood that in order to focus during variable power, it is necessary not only to change the total optical path length yc but also to change ya or yb. This ya, yb
can be changed by moving the variable power lens block 8 in the y direction. Further, the total optical path length yc can be changed by moving the second carriage 412 and changing the position of the mirror 6.7.

On the other hand, as shown in FIG. 11(b), the distances between the document table 2, the variable magnification lens block 8, and the photosensitive drum 10 are kept constant, and the variable magnification lens block 8 is moved in the X direction by the motor 67, for example, by a distance x When the image on the photosensitive drum 10 is moved by 1, the image on the photosensitive drum 10 is moved by a distance x 2 expressed by the following equation.

X2-XI Xyb/Va Also, in the case of a same size copy, it becomes X2-2Xt. In this way, by moving the variable magnification lens block 8 in the X direction, the center of the copied image can be moved.

FIG. 12 shows the overall control circuit, in which the main processor group 71 and the first . 2nd subprocessor group 72.73
It is mainly composed of. The main processor group 71 includes an operation panel 30 and various switches and sensors such as the cassette size detection switch 601, 602, and 603.
A high-voltage transformer 76 that detects input from an input line device 75 such as the like and drives the various chargers, the static elimination lamp 27,
The blade solenoid 26a of the cleaner 26, the heater 21a of the pair of fixing rollers 21, the exposure lamp 4, and each of the motors 31 to 40, 58, 67, etc. are controlled to perform the above-described copying operation. The second optical detectors 130 and 134 and the memory 137 are used to detect misalignment of the sheet in the horizontal and vertical directions, and according to the detected position, an operation is performed to adjust the image forming position on the sheet.

In addition, the first and second optical detectors 130 and 134, the memory 1
The details of 37 will be described later.

Among the above motors 31 to 40,58,67, motor 35
1.352.37, 40.401 and developer 121.
Toner motor 77.771 that supplies toner to 122
is connected to the main processor group 7 via the motor driver 78.
1, the motors 31 to 34.67 are controlled by the first sub-processor group 72 via a pulse motor driver 79, and the motors 36, 39, 38.58 are controlled by the second sub-processor group via a pulse motor driver 80. It is controlled by a processor group 73. In addition, the exposure lamp 4 is connected to a lamp regulator 8.
The heater 21a is controlled by the main processor group 71 via the heater control section 82. Then, from the main processor group 71, the first. Commands to drive and stop each motor are sent to the second sub-processor group 72, 73, and the first. A status signal indicating the drive/stop state of each motor is sent from the second sub-processor group 72, 73 to the main processor group 71. The first sub-processor group 72 also includes motors 31 to 34.
．． Position information from a position sensor 83 that detects each initial position of 67 is input.

FIG. 13 shows an example of the configuration of the main processor group 71. That is, 91 is a one-chip microcomputer (hereinafter simply referred to as microcomputer), which detects human input of keys on an operation panel (not shown) and controls various displays via an input/output board 92. Further, the microcomputer 91 is expanded by input/output ports 93-96. A high voltage transformer 76, a motor driver 78, a lamp regulator 81, and other outputs are connected to the input/output boat 93. A size switch for detecting paper size and other human power are connected to the input/output boat 94. 95 is connected to a copy condition setting switch and other human power.

Note that the input/output port 96 is an option.

FIG. 14 shows an example of the configuration of the first sub-processor group 72. That is, 101 is a microcomputer, which is connected to the main processor group 71. 102 is a programmable interval timer for controlling the phase switching interval time of the pulse motor, and when a set value is set from the microcomputer 101, it counts based on it, and when it has counted out, it sends an end pulse to the interrupt line of the microcomputer 101. Output. A reference clock pulse is input to the timer 102. Further, the microcomputer 101 receives position information from the position sensor 83, and input/output board 103.1.
04 is connected. And the input/output boat 10
4 are connected to the motors 31 to 34.67 via the pulse motor driver 79. The input/output board 103 is used, for example, to output status signals of each pulse motor to the main processor group 71.

FIG. 15 shows the configuration of the second sub-processor group 73. That is, 111 is a microcomputer, which is connected to the main processor group 71. Numeral 112 is a programmable interval timer for controlling the phase switching interval time of the pulse motor, and when a set value is set by the microcomputer 111, it counts based on the set value, and outputs an end pulse when the count is out. This termination pulse is latched by the latch circuit 113, and its output is
11 interrupt lines and input/output port input lines. Further, an input/output boat 114 is connected to the microcomputer 111, and the motors 36, 38, 39 are connected to the input/output boat 114 via the pulse motor driver 80.
．． 58 are connected.

Figure 16 shows the control circuit of the pulse motor.
04.114) has a pulse motor driver 122
(Equivalent to pulse motor driver 79.80 in Figure 12)
A pulse motor 123 (the pulse motors 31 to 34, 36, 3) is connected to this pulse motor driver 122.
8.39.58.67) each winding A%B, A, B
is connected.

Figure 17 shows a method for controlling the speed of a pulse motor.

Figure (a) shows the speed curve of the pulse motor, and Figure (b) shows the speed curve of the pulse motor.
) indicates the phase switching interval. As is clear from this figure, the phase switching interval is initially long, gradually shortens, eventually becomes equal, becomes gradually longer again, and then stops. That is, this indicates the slew-up and slew-down of the pulse motor, starting from the self-starting region, being used in the high-speed region, and finally falling down. In addition, t, ,
t2...tx indicates the time of the phase switching interval.

Next, the main parts of the text will be explained. In this embodiment, it is possible to correct paper misalignment. That is,
As shown in FIGS. 1(a) and 1(b), in front of the registration roller pair 17 with respect to the traveling direction of the paper P, there is the first optical detector 130 for detecting a lateral positional deviation of the paper P. is provided. This optical detector 130 is, for example, a paper P.
A light emitting element 131 and a plurality of light receiving elements 1 are arranged at predetermined intervals in a direction perpendicular to the front and back sides of the
The light receiving element group 133 includes 32 light receiving elements. In the light-receiving element group 133, as shown in FIG. 2B, the central portion of the plurality of light-receiving elements 132 arranged in a straight line is aligned with the conveyance reference position ST of the paper P. Therefore, when the paper P deviates from the reference position ST, such as P2 or P2, the output signal of the light receiving element group 133 changes, and from this it is possible to detect the positional deviation amount 1x of the paper P in the X direction. . Then, based on the detected positional deviation amount 1x, if the copying magnification is equal to the same magnification, the variable magnification lens block 8 is moved by IX/2 in the X direction,
In the case of non-uniform placement, the amount of correction is determined by the method described above, and the variable magnification lens block 8 is moved in accordance with this amount of correction, thereby making it possible to form an image in accordance with the reference position of the paper.

Further, the registration roller pair 17 and the transfer charger 1
8 (shown in FIG. 5), a second optical detector 134 is provided to detect a positional deviation of the paper P along the moving direction (hereinafter referred to as a vertical positional deviation). . The detector 14 includes a light-emitting element 135 and a light-receiving element 136, which are inspected at a predetermined interval from the pair of registration rollers 17, and are back-exposed at a predetermined interval from the front and back sides of the sheet P, respectively. In such a configuration, vertical positional deviation of the paper P is caused by the paper P being taken out from the paper feed cassettes 131 to 133 or the stacking section 28a, and detected by the second optical detector 13.
It is determined based on the temporal timing until the tip is detected by 4. That is, when the copy key 301 is operated, the sending rollers 141 to 143 and the roller pair 1
51 to 153 and the registration roller pair 17 are driven.

Further, when the double-sided multiple copying unit 28 is selected, the sending roller 28e, the pair of separating rollers 28f, and the pair of conveying rollers 28h and 28j are driven.

Among the motors that drive these rollers, the motor 39 that drives the pair of registration rollers 17 is a pulse motor as described above. Therefore, the number of pulses supplied to this motor 39 is counted by the main processor group 71, and the second If this counting is stopped when the leading edge of the paper P is detected by the optical detector 134, the moving distance of the paper P can be determined from this counted value. Therefore, by setting a reference value corresponding to the moving distance of the paper in advance, it is possible to determine the error (the amount of vertical positional deviation 1y of the paper P) with respect to this reference value.

In the above configuration, the operation will be explained. For example, when the multiple copy setting key 30a of the operation panel 30 is operated,
When multiple copying is set, the copy key 30
When 1 is pressed, the main processor group 71
Operation control is performed according to the flowchart shown in the figure. That is, in step S1, paper P is fed from the selected paper feed cassette, and in step S2, the first
, second optical detectors 130 and 134 detect the horizontal and vertical positional deviation amounts IXI and Iyl of the sheet P. This detected positional deviation [1Ix1, IVt is stored in the memory 137 in step S3. In this case, a normal copying operation is performed in step S4. When this copying operation is completed, the double-sided multiple copying unit 28 is operated in step Ss, and the paper P on which the image has been formed is stored in the stacking section 28a of this unit 28. Thereafter, when another document is set on the document table 2 and the copy key 301 is operated again, the paper P is again supplied to the transfer section. At this time, in step S6, the horizontal and vertical positional deviations IX2 of the paper P are again detected.
, I'l'2 is detected, and in step S7, the detected positional deviation amount lXz,ly2 and the memory 1
The positional deviation amounts 1x1 and Iyl stored in 37 are subtracted, respectively, and the errors Ex-(IXI-IX2) and Ey"
(IVt-11!/2) is calculated. In step S8, the variable magnification lens block 8 is operated based on the calculated error Ex, and the image forming position is moved in accordance with the lateral positional deviation of the paper P. In this case, the displacement llIm of the variable magnification lens block 8 is EX/2 when the copying magnification is equal to the same magnification. After that, in step S9, the copying operation is started, and at this time, depending on the calculated vertical error Ey, for example, the registration roller pair 17
The timing of the operation is changed, and the timing of supplying paper to the transfer section is changed. Therefore, an image is formed on the paper P with the horizontal and vertical positional deviations between the previous and current images corrected. When this copying operation is completed, the copied paper P is discharged onto the tray 35 in step S1o, and all operations are completed.

Note that when the number of copies is set to multiple copies, first, the detected horizontal and vertical positional deviation amounts of each paper are stored in the memory 137 corresponding to the first copy, and the number of copies is stored in the memory 137. is accommodated in the accumulation section 28a. Thereafter, when multiple copying is performed, errors are determined from the positional deviation amount detected corresponding to the sheets sequentially supplied from the stacking section 28a to the transfer section and the positional deviation amount stored in the memory 137. The image forming position is corrected according to this error.

According to the above embodiment, the first and second optical detectors 130.
134, detects the horizontal positional deviation amount lx and the vertical positional deviation amount 1y of the fed paper P, and
These positional deviation amounts 1x and Iy are stored in the memory 137, the error between the stored positional deviation amount and the positional deviation amount detected again during multiple copying is determined, and the variable magnification lens block 8 is adjusted in response to this error. Along with the movement, the operation timing of the pair of registration rollers 17 is shifted to perform the copying operation. Therefore, even if the position of the paper supplied to the transfer section is shifted in the horizontal and vertical directions, it is possible to form an image according to the reference position of the paper. For this reason, especially when performing multiple copies,
Since no deviation occurs in the formed image, it is possible to improve the quality of the copied image.

In the above embodiment, the case of multiple copying operation has been explained, but the present invention is not limited to this. Misalignment of paper is detected during double-sided copying operation or normal copying operation, and the image forming position is corrected based on this. You may also do this.

Further, as the light receiving element group 133, a plurality of light receiving elements 13
2 is used, but the present invention is not limited to this, and for example, a CCD line sensor 140 may be used as shown in FIG. With such a configuration, it is possible to detect paper misalignment with high precision.

It goes without saying that various other modifications can be made without departing from the gist of the invention.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to prevent the lateral positional shift of the transfer material, and to provide an image forming apparatus that can form a high-quality image. can.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of an image forming apparatus according to the present invention. FIG. 1(a) is a perspective view of the main part showing an optical detector, and FIG. 4 and 5 are perspective views of essential parts showing an optical detector, respectively, showing the configuration of the image forming apparatus.
The figure is a perspective view of the external appearance, Figure 5 is a side sectional view, Figure 6 is a plan view showing the configuration of the operation panel, Figure 7 is a perspective view showing the configuration of the drive section, and Figure 8 is the drive mechanism of the optical system. FIG. 9 is a perspective view schematically showing a pointer drive mechanism;
Figure 0 is a perspective view of the main parts showing the configuration of the variable power lens block, Figure 11 is a diagram shown to explain the operation of the variable power lens block, and Figure 12 is a configuration diagram showing the overall control circuit. , FIG. 13 is a configuration diagram showing the main processor group, and FIG. 14 is a configuration diagram showing the main processor group.
Figure 15 is a block diagram showing the first sub-processor group, Figure 15 is a block diagram showing the second sub-processor group, Figure 16 is a schematic diagram showing the control circuit of the pulse motor, and Figure 17 is speed control of the pulse motor. FIG. 3 is a diagram for explaining the method. DESCRIPTION OF SYMBOLS 1... Main body, 2... Original table, 8... Lens block for variable magnification, 10... Photosensitive drum, 121.122.
... Phenomenon, 17... Registration roller pair, 28...
Double-sided multiple copy unit, 30...operation panel, 71.
...Main processor group, 130.134...1st,
Second optical detector, 131.135... Light emitting element, 1
32.136... Light receiving element, 137... Memory, 1
40...COD line sensor. Applicant's agent Patent attorney Takehiko Suzue Figure 1 (b) Figure 2 Figure 3 Figure 4rl! J 7th prisoner 9rI! J Figure 10 Figure 11 (a)

Claims (3)

[Claims] (1) A scanning means that optically scans a document placed on a document table, a transfer means that transfers an image corresponding to the document image guided by the scanning means to a transfer material, and an image is formed. In an image forming apparatus comprising a conveyance means for conveying the transferred material to the transfer means again, an image forming apparatus is provided near the transfer means to detect the amount of positional deviation corresponding to a direction orthogonal to the moving direction of the transfer material. a detection means, a storage means for storing the amount of positional deviation outputted from the detection means, the amount of positional deviation stored in the storage means and the position of the paper conveyed by the conveyance means and detected again by the detection means; An image forming apparatus comprising: a control means for correcting an image forming position on the transfer material according to an error with a deviation amount. (2) The image forming apparatus according to claim 1, wherein the detection means comprises a light receiving element. (3) The control means, depending on the error in the positional deviation amount,
2. The image forming apparatus according to claim 1, wherein the image forming apparatus controls the movement of a variable magnification lens block.