JPS61275780A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent a material to which an image is transferred from shifting in position laterally and to form an image of excellent quality by moving a lens block for power variation according to the output signal of a lateral position shift detector and correcting an image formation position. CONSTITUTION:An optical detector 130 which detects the lateral position shift of a form P is provided in front of a register roller couple 17 and this detector 130 consists of light emitting element 132 and a photodetecting element group 133 of plural photodetecting elements 132 which are arranged at specific intervals on both sides of the form P perpendicularly. The center part of the plural elements 132 which are arranged linearly is aligned with the reference conveyance position ST of the form P and when the center part shifts from the position ST, the output signal of the element group 133 varies and the quantity Ix of the position shift of the form P is detected. The lens block for power variation is moved in an (x) direction by Ix/2 (when copy magnification is life size, etc.) on the basis of the quantity Ix of the position shift. Consequently, an image is formed according to the reference position of the form to improve the quality of the image.

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, the paper once copied is conveyed again to the 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. In particular, when multiple copies are made, there is a problem in that when such positional deviation occurs, the quality of the copies is severely impaired.

[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]

In this invention, for example, an optical detector is provided in front of the registration roller to detect a lateral positional deviation of the paper, and the variable magnification lens block is moved in the moving direction of the first carriage in accordance with the output signal of this detector. It moves in the orthogonal direction and corrects the image forming position with respect to the paper on which the image has already been formed.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to a concave surface.

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 copying body, and an original table (transparent glass) 2 for supporting an original is fixed on the upper surface of this main body 1. The document table 2 is provided with a fixed scale 2) that serves as a reference for setting documents, and furthermore, a document cover 11 and a work table 12, which can be opened and closed, are provided near the document table 2. The original placed on the original platen 2 is moved back and forth by an optical system consisting of an exposure lamp 4 and mirrors 5, 6, and 7 along the lower surface of the original platen 2 in the direction of arrow a. It is designed to be exposed and scanned. 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 further passes through the mirror 91. .

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 formed by a developing unit 12) which contains, for example, red or black toner, and is selectively operated as required. 122, a toner is attached to the surface to form a visible image.

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.
3 and roller pair 151.152.153, and are guided through a paper guide path 161.162.16:l to a registration roller pair 17, and guided by this registration roller pair 17 to a transfer section. It has become. Here, the above paper feed cassette 131.132.13
3 is removably provided at the lower right end of the main body 1, and either one can be selected on the operation panel described later. Note that each of the paper feed cassettes 131.
The cassette sizes of the cassettes 132 and 133 are detected by cassette size detection switches 60r and 602 and 603, respectively. The cassette size detection switches 601.6o2.603 are composed of a plurality of microswitches that are turned on and off in accordance with 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 1o 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 a conveyor belt 20, and is sent to a fixing roller 2) as a fixing device provided at the end of the conveyor belt 20, where the transferred image is transferred. is established. Then, paper P after fixing
The sheets are placed on 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. After the transfer, the photosensitive drum 10 is returned to its initial state by removing residual toner on the surface with a cleaner 26 and erasing any afterimages with a static elimination lamp 27. 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.
128C and 28d are provided. Further, the stacking section 28a is provided with a delivery roller 28e that sends 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 is guided to the control gate 28g via a separation roller pair 28f that separates and sends out the paper sheets one by one. When performing multiple copying, the control gate 2BQ is rotated in the direction of the arrow M shown in the figure to guide the paper to the registration roller pair 17 via the paper guide path 281 of the transport roller pair 28h1.

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 28i;
7.

FIG. 6 shows the operation panel 30 provided on the main body 1. 301 is a copy key for instructing the start of copying; 302
numeral keys for setting the number of copies, etc., 303 a display section for displaying the operating status of each section and paper jams, etc., 304 a cassette selection key for selecting the upper and lower paper feed cassettes 13r, 132 and 133, and 305 a selected cassette. 306 is a magnification setting key for setting the enlargement/reduction magnification of copying in a predetermined relationship, 307 is a zoom key for steplessly setting the enlargement/reduction magnification, and 30g is for displaying the set magnification. 309 is a density setting section for setting the copy density, 30a is a multiple copy setting key, 30b
is a duplex copy setting key, 30c is a red designation key that designates, for example, the developing device 12 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.

A scanning motor 33 is a motor for moving the exposure lamp 4, the mirror 5, and the mirror 6.7 for scanning the original. A shutter motor 34 is a motor for moving a shutter (not shown) for adjusting the charging width of the photosensitive drum 10 by the charger 11 during zooming. 351 and 352 are developing motors, respectively, and the developing units 12). This is a motor for driving the developing roller 122, etc. 36 is a drum motor, which is a motor for driving the photosensitive drum 10. A fixing motor 37 is a motor for driving the paper conveyance path 20 and the fixing roller pair 2). 38 is a paper feed motor, and the feed roller 14
This is a motor for driving 1 to 143. Reference numeral 39 denotes a paper feed motor, which is a motor for driving the registration roller pair 17. 40 is a fan motor;
A motor 401 for driving the cooling fan 29 is a five-row pair 24.28b, 28c.

This is a motor for driving 28d, etc.

FIG. 8 shows a drive mechanism 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, 412 are guided by guide rails 42), 422 in the direction of arrow a. It can be moved freely 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 stretched between 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 the first carriage 41 is fixed to the middle part of the wire 48. Therefore, as the pulse motor 33 rotates, the belt 4
5 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. Note that the moving directions of the first and second carriages 411 and 412 are 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
Let the paper size specified by (Px, Py) be,
If the copy magnification specified by the magnification setting keys 306 and 307 is K, the copyable range (x, y), "x-Px
/K”.

It becomes rV-Py/KJ. This copyable range (X.

y), the X direction is indicated by the pointers 51 and 52 provided on the back surface of the document table 2, and the y direction is indicated by the scale 53 provided on the top surface of the first carriage 411. ing.

As shown in FIG. 9, the above-mentioned pointers 51 and 52
．． 55 via a spring 56. The brake 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 301 is pressed, the first
The carriage 41t is first moved toward the second carriage 412, and then the lamp 4 is turned on and 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. Bushes 631 and 632 provided at one end of the base plate 62 are screwed into the lead screw 61.
1 is rotated, the substrate 62 is moved in the y direction.

A guide member 62) is provided at the other end of the substrate 62, and the guide member 62) is slidably engaged with a 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 above, and to which the variable magnification lens block 8 is attached. That is, supports 651. are provided at both ends of the moving body 65.
652 is provided, and these supports 65r, 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 side surface 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 variable magnification lens block 8 is operated by the motor 67.
is moved in the X direction by being driven. The microswitches 691 and 692 detect 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 1o. 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/'/a+1/yb 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 respective distances between the document table 2, the variable magnification lens block 8, and the photosensitive drum 10 are fixed, and the variable magnification lens block 8 is moved by the motor 67 in the X direction, for example, by a distance. When moving by XI, the photoconductor drum 1o
The upper image is moved by a distance x 2 given by the following equation.

X2-Xt 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 60s and 602.60.
A high-voltage transformer 76 that detects input from an input device 75 such as i and drives the various chargers, and the static elimination lamp 27.
, a blade solenoid 26a1 of the cleaner 26; a heater 2)a1 of the pair of fixing rollers 2); a1 the exposure lamp 4;
and controls each of the motors 31 to 40, 58, 67, etc. to perform the above-mentioned copying operation, and also controls the optical detector 1.
30 is used to detect a positional shift in the lateral direction of the paper, and according to the detected position, an operation is performed to adjust the image forming position on the paper. Note that details of the optical detector 130 will be described later.

Among the above motors 31 to 40,58,67, motor 35
1.352.37, 40.401 and developer 12).
Toner motor 77.771 that supplies toner to 122
is connected to the main processor group 7 via the motor driver 78.
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, and 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 2)a 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. Further, the first sub-processor group 72 receives position information from a position sensor 83 that detects the initial positions of the motors 31 to 34.67.

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 from 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. A close-up condition setting switch and other human power are connected to 95.

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, position information from the position sensor 83 is input to the microcomputer 101, and the input/output boat 103.
104 is connected. And the above input/output boat 1
The motors 31 to 34.67 are connected to the motor 04 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.

112 is a programmable interval timer for controlling the phase switching interval time of the pulse motor;
By setting a set value from 1, it counts based on it, and outputs an end pulse when the count is out. This termination pulse is latched by the latch circuit 113, and its output is supplied to the interrupt line and input/output board input line of the microcomputer 111. Further, an input/output boat 114 is connected to the microcomputer 111, and motors 36, 38, 39, and 58 are connected to the input/output boat 114 via the pulse motor driver 80.

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) windings A, B, A1B
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, tl',
t2...tx indicates the time of the phase switching interval.

Next, main parts of the present invention will be explained. In this embodiment, it is possible to correct paper misalignment. That is,
As shown in FIGS. 1(a) and 1(b), the optical detector 130 for detecting a lateral positional deviation of the paper P is provided in front of the pair of registration rollers 17 with respect to the traveling direction of the paper P. ing.

The optical detector 130 includes, for example, a light-emitting element 131 and a light-receiving element group 133 including a plurality of light-receiving elements 132, which are arranged at predetermined intervals in a direction perpendicular to the front and back sides of the paper P. 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.
It is possible to detect the amount of positional deviation 1x. 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 By determining the correction layer using the method and moving the variable magnification lens block 8 according to this correction amount, it is possible to form an image according to the reference position of the paper.

In the above configuration, the operation will be explained. For example, when the multiple copy setting key 30a of the operation panel 3o 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 a normal copying operation is performed on this paper P. After this, in step S2,
The copied paper P is stored in the double-sided multiple copying unit 28. For example, when the copy key 301 is pressed while another document is set on the document table 2,
The paper P is again supplied to the transfer section by the double-sided multiple copying unit 28. At this time, if the paper P blocks the optical detector 130, the paper P
A positional deviation llx from the reference position ST is detected. After this, in step S4, the detected positional deviation amount 1
The motor 67 is driven in accordance with x, and the variable magnification lens block 8 is moved in the X direction (direction along the deviation of the paper P). In this state, a copying operation is performed in the same manner as described above in step S5, and when the copying operation is completed, the paper P on which multiple copies have been made is discharged to the tray 25 in step S6, and all operations are completed.

According to the above embodiment, the optical detector 130 detects the lateral positional deviation amount IX of the fed paper P, moves the variable magnification lens block 8 in accordance with this positional deviation amount 1x, A copy operation is performed. therefore,
Even if the position of the paper supplied to the transfer section changes, it is possible to form an image according to the reference position of the paper. Therefore, especially in the case of multiple copying, no deviation occurs in the formed images, so it is possible to improve the quality of the copied images.

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, and FIG. 1(a) is a perspective view of the main part showing an optical detector, and FIG. 1(b) is a diagram illustrating paper misalignment. FIG. 2 is a plan view of the main parts shown for explaining the operation; FIG. 3 is a perspective view of the main parts showing another embodiment of the invention and shows an optical detector; 4 and 5 show the configuration of the image forming apparatus, respectively. FIG. 4 is an external perspective view, FIG. 5 is a side sectional view, FIG. 6 is a plan view showing the configuration of the operation panel, and FIG. 8 is a perspective view schematically showing the drive mechanism of the optical system, and FIG. 9 is a perspective view schematically showing the drive mechanism of the pointer. 5! 10 is a perspective view of the main part showing the configuration of the variable power lens block, and FIG.
The figures are diagrams shown to explain the operation of the variable magnification lens block, Figure 12 is a configuration diagram showing the overall control circuit, and Figure 13 is a diagram showing the overall control circuit.
The figure is a configuration diagram showing the main processor group.
FIG. 15 is a block diagram showing the sub-processor group, FIG. 15 is a block diagram showing the second sub-processor group, FIG. 16 is a schematic block diagram showing the control circuit of the pulse motor, and FIG. 17 explains the speed control method of the pulse motor. This is a diagram for DESCRIPTION OF SYMBOLS 1... Main body, 2... Original table, 8... Lens block for variable magnification, 10... Photosensitive drum, 12). 122・
...Developer, 17...Register roller pair, 28...
Double-sided multiple copy unit, 30...operation panel, 71.
・・Main processor group, 130 ・・Optical detector, 1
31... Light emitting element, 132... Light receiving element, 140.
・CCD line sensor. Applicant's agent Patent attorney Takehiko Suzue (b) Figure 2 Figure 4 Figure 7y! J 3g9 [Figure 11

Claims (3)

[Claims] (1) A scanning means for optically scanning a document placed on a document table; a transfer means for transferring an image corresponding to the document image guided by the scanning means onto a transfer material; In an image forming apparatus comprising a moving means for changing the image forming position and a conveying means for conveying the transferred material on which the image is formed to the transferring means again, the moving direction of the transferred material is provided near the transferring means. The image forming apparatus is characterized by comprising: a detection means for detecting a positional deviation in a direction perpendicular to the direction; and a control means for operating the moving means in accordance with an output signal of the detection means to correct the position at which the image is formed on the transfer material. image forming device. (2) The image forming apparatus according to claim 1, wherein the detection means includes a plurality of light receiving elements arranged in a direction perpendicular to the moving direction of the transfer material. (3) The image forming apparatus according to claim 1, wherein the detection means comprises a CCD arranged in a direction perpendicular to the moving direction of the transfer material.