JPH01281468A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain an excellent image without the deviation in transfer and the blurring of image by controlling respective image forming parts based on a detection signal outputted from a position detecting mark detection means so that the blurring of a transferred image is corrected. CONSTITUTION:The respective image forming parts Pa-Pd are controlled to correct the blurring of the transferred image based on the detection signal outputted from the position detecting mark detection means 24R and 24L which is provided on a downstream side in the moving direction of a moving member 6 in a transfer area and detects the position detecting marks 15R and 15L transferred on the moving member 6. Even if a failure, such as a lag occurring in image forming timing or the deviation occurring in mechanical positional relation of the respective image forming parts Pa-Pd in various kinds of causes, occurs the failure is automatically removed without troubling a professional engineer such as a service man, etc. Thus, the image of excellent quality without the deviation in transfer and the blurring of image can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention generally relates to an image forming section, and particularly relates to, for example, an electrophotographic copying apparatus in which two or more image forming processes are arranged in parallel;
The present invention relates to polynomial image forming devices such as laser beam printers and printing devices.

Generally, this type of image forming apparatus forms visible images of different colors in a plurality of image portions.

The visible images of these different colors are successively superimposed and transferred onto a sheet of transfer material that is conveyed to each of the image forming sections by a belt-like conveyance means, for example. Each of the above-mentioned image forming units has the same configuration, and includes an optical scanning device d such as a laser beam scanner that scans a given original image, and an electrostatic latent image formed by image exposure irradiated from the neck optical scanning device. It has a photoreceptor drum to be formed, and a developing device for converting the electrostatic latent image formed on the photoreceptor drum into a visible image. The photoreceptor drum and transfer material conveyance belt mentioned above are driven to rotate at a predetermined speed, but due to load fluctuations and frictional fluctuations in these photoreceptor drums and transfer material conveyance belt, The speed fluctuates, and due to this speed fluctuation, a transfer deviation of each of the visible images to the same transfer material occurs. Such transfer misalignment causes problems such as color bleeding and hue changes in color images. The above-mentioned problems can be resolved by controlling the rotational speed of the transfer material conveyance belt, photoreceptor drum, etc., thereby suppressing speed fluctuations caused by load fluctuations occurring in these parts, and maintaining the set speed at all times. I am forced to do it. In addition, if there is a discrepancy in the timing of image formation in each of the image forming units described in B1, there may be a change in the mounting position between each image forming unit and the transfer material conveyance belt or in each image forming unit. Even when this occurs, transfer deviation and image deviation as described above occur. For example, such transfer deviation or image deviation may occur.

8th F! 4(a) in the transfer material SI conveyance direction (
Transfer material S as shown in (b)
u4 Positional deviation in the direction perpendicular to the feed direction (direction B in the figure) c l
! +1 is also referred to as [left margin deviation]), the inclination deviation of the transfer material SI @ feeding direction and diagonal direction as shown in Fig. 8(C), and the sharp magnification error shown in Fig. 8(d). Misalignment can be classified into four types. Among the transfer deviations and image deviations mentioned above, the top margin deviation shown in FIG. 8(a) and the left margin deviation shown in FIG. 8(b) are caused by the light beam irradiated from the optical scanning device. The scanning timing of the optical scanning device is corrected by controlling the drive of the optical scanning device.
The magnification deviation shown in Figure (cl) can be corrected by mechanically micro-displacing each of the above-mentioned image forming units or each part of the optical scanning device that constitutes each of these image forming units. I am doing it.

By the way, in the conventional image forming apparatus having the above-mentioned configuration, if the transfer deviation is caused by speed fluctuations of the photoreceptor drum and the transfer material conveying belt, one image forming apparatus While driving, there is no problem because the rotational speed of each member is always automatically controlled and the speed fluctuation is thereby eliminated.However, there is no problem.
If the transfer deviation or the like is caused by the above-mentioned timing deviation in image formation or a mechanical malfunction in each of the image forming sections, the following problems occur. In other words, the above-mentioned timing difference in image formation and the various image types mentioned above! Mechanical malfunctions in the & section are caused by maintenance of the image forming device by a general user, or by some external shock being applied to the image forming book or image forming. This occurs due to changes in the environment surrounding cW1. When some kind of external impact is applied to the image forming unit or the environment surrounding the image forming apparatus changes, the positional relationship between the eight image forming units changes, and the image forming units forming each image forming unit change. There is a risk that the parts themselves may be deformed.

In addition, when general users perform maintenance of the image forming apparatus, or when an abnormal operation such as a paper jam occurs during the operation of the image forming apparatus,
A general user can release each image forming unit from the operating position or
After replacing parts, etc., when attempting to return the image forming sections and parts to their original positions, there is a risk of slight positional deviations occurring.

Although it is impossible to eliminate such a problem unless the deviation in the timing of one image formation and the deviation in the mechanical positional relationship of each image forming section is corrected, the deviation in the timing of four image formations Since the electrical adjustment of the image forming apparatus and the mechanical position adjustment of each image forming section require a certain level of specialized skill and effort, it is difficult for general users to accurately perform the above operations. Furthermore, the above-mentioned 7A adjustment by a professional engineer is limited to the assembly ψ adjustment of the product (that is, the image forming unit!) before shipping, and the installation of the device by a service person. When the above-mentioned problem occurs, there is a problem in that it is impossible to correct the transfer deviation and image deviation and obtain a good quality image without bothering two service personnel or the like.

Therefore, uninvention is 1: mentioned 1. This system was invented to improve the problems caused by the 212 I! After alignment has been performed, due to various reasons, there may be discrepancies in the timing of image formation, or the mechanical position of each image forming section may be affected.
Even if a problem occurs such as a misalignment in the 5fl section, the problem will be automatically resolved without the need for service personnel or other specialized technicians. It is an object of the present invention to provide an image forming bag AT-M that can obtain images with good Ti quality.

l ta : tJ bipedalism is achieved by the image forming apparatus according to the present invention. In summary, the present invention includes a plurality of image forming units that form a visible image corresponding to document image information and also forms a visible image of a position detection mark; Sequentially provide transfer areas to transfer visible images corresponding to the original document image information or visible images of position detection marks! !
11, a moving member passing through the moving member-L, and a position detecting mark detecting means provided on the downstream side in the moving direction of the moving member in the transfer area and detecting a position detecting mark transferred to the moving member-L, The image forming apparatus is characterized in that each of the image forming sections is controlled to correct transfer image shift based on a detection @ signal output from a detection mark detection means.

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

FIG. 1 shows an image forming apparatus according to an embodiment of the present invention. IEff of an image forming apparatus according to an embodiment of the present invention is as follows.
It is as described below. That is, in FIG. 1, a driving roller 11 and a driven roller 12 are arranged opposite to each other with a predetermined distance apart in a lower area within the apparatus main body (not shown).
A moving member, that is, a transfer material conveying belt 6 is provided.
is wound around and supported by the drive roller 11 and driven roller 12. In the upper area of the transfer material conveying belt 6 in the apparatus main body (not shown), four image forming units Pa, Pb, Pc,
Pd are arranged in parallel at approximately equal intervals.

The above configuration will be described in more detail as follows. The image forming sections Pa, Pb, Pc, and Pd have the same configuration.The image forming section Pa forms an image of a portion corresponding to the cyan color in the extracted original image information.For example, Including the optical scanning device 113c such as a laser beam scanner, the optical scanning device! ! Photosensitive drum IC where an electrostatic latent image is formed by image exposure irradiated from 3G
And, there is static electricity on the photoconductor drum ICJ: such as a cleaner, a charger, etc. provided around the photoconductor drum IG. means necessary for forming the l image (not shown);
Like the developing device that houses the cyan developer that is installed around the photoreceptor drum IC! ! It has a means (not shown) necessary for developing the electrostatic latent image, and a transfer charger (not shown) necessary for transferring the developed image to a transfer material etc. . The optical scanning device 3
C is provided with stepping actuators 40.41. #Light scanning device! Regarding the configuration of 3C and the configuration of these stepping actuators 40 and 41,
The 0 image forming section Pb will be described in detail later.

It forms an image of a portion corresponding to magenta in the given document image information, for example, an optical scanning device 3M such as a laser beam scanner, M optical scanning! The image forming section Pc includes a photosensitive drum IM on which a latent image is formed by image exposure irradiated from the eff13M, a developing device (not shown) containing magenta developer, etc. ,
This system forms an image of a portion corresponding to the yellow color in the given document image information, and uses image exposure emitted from the optical scanning device 3Y, such as a laser beam scanner, and the optical scanning device 13Y, to remove electrostatic latent light. A photoreceptor drum IY on which an image is formed, a developing device containing yellow developer (
The 0 image formation reduction Pd, which has the following functions (not shown), forms an image of a portion corresponding to the black color in the received original image information. device 38K, the optical scanning device 13
0 image forming sections Pb and Pc, which have a photosensitive drum IBK on which an electrostatic latent image is formed by image exposure irradiated from 8K, a developing device (not shown) containing a black developer, etc. , Pd are equipped with III devices similar to those described in the image type L& section Pa in addition to the above, and explanations regarding these devices will be omitted. As is clear from FIG. 1, the photoreceptor drums IC, IM, IY, and IEK all move in the direction of the arrow in FIG.
It is configured to be rotatable in the clockwise direction.

Transport the transfer material! Retro is made of transparent material and has a paper feed mechanism (located on the right side of Figure 1).
A transfer material S such as a transfer paper supplied from a paper (not shown) is placed thereon and conveyed (in the direction of the arrow in FIG. 1) toward each image forming section Pa, Pb, Pc, and Pd. The transfer material conveying belt 6 includes the aforementioned drive roller 11. Driven roller 1
2, it is also wound around a tension roller 13 which is provided diagonally below the drive roller 11 and applies tension to the transfer material conveying belt 6 by means of a spring (not shown). The belt 6 in the area between the photosensitive drum IBK and the driver 11 of the transfer material conveying belt 6
Mark detection means for position detection, that is, mark reading devices 24R524L are provided facing each other on both sides in the transport direction. The mark reading device! ! 24R22
4L is formed on the non-lli image forming area of each photoreceptor drum IC, LM, IY, and IBK before the image forming apparatus executes the image forming process, and is transferred in the conveying direction fqa of the transfer material conveying belt 6. A roughly cross-shaped position detection mark (hereinafter referred to as a "register mark") as shown in Figure 3.
15R115L (referred to as )15R115L, and both have the same 4a configuration. @mark reading device 24K,
Lenses 31.24L serve as detection sections, respectively. A CCD tin sensor 33 that serves as a light receiving section, and an illumination lamp 30 that serves as an illumination section.
Equipped with etc. In addition, the mark reading device 24R124
Details of L and the register marks 15R and 15L will be described later. A cleaner blade 14 is attached to the outer peripheral side of the transfer material transport belt 6 in the vicinity of the tension roller 13 so as to be in contact with the outer peripheral surface of the transport belt 6. The drive roller 11 is designed to remove the registration marks 15R and 15L transferred to the outer peripheral surface of the conveyor belt 6 in the step before carrying out the process. A motor 1o is attached to drive the dovetail in one counterclockwise direction. The motor 10 is provided with a pulse encoder CIA (not shown), and the rotation speed of the motor 10 is subjected to phase locked loop control (hereinafter referred to as rPLL control) based on a rotation speed detection signal output from the pulse encoder. Similar to the motor 10, the photosensitive drum I
c, LM, IY, l A pulse enneader (not shown) is also provided on the photoreceptor drum drive motor (not shown) that drives BKle, and the rotational speed of the motor is PLLi.
tjNM. PLL1til
Since W is already a well-known technique, its explanation will be omitted.

In the configuration described above, when the transfer material S is supplied to the transfer material conveying belt 6 at a predetermined timing from the paper feeding device (not shown) provided on the right side of FIG. Receive the transfer material S, place it, and move it toward the left in Figure 1 (
That is, it is transported in the direction of the arrow in FIG. Transfer material S
When the images are conveyed, each image forming section Pa, Pb, Pc,
Pd transfers toner images of each color of cyan, magenta, yellow, and black formed on each photoreceptor drum through various steps of charging, exposure, and development onto the M-th transfer material S. When the above-mentioned transfer process i~ is completed, the transfer material S
is conveyed by the transfer material conveyance belt 6 to a fixing device (not shown) provided on the left side of FIG.
(not shown), etc.

1) 2 [Is this a picture based on the uninvented embodiment shown in FIG. 1? This figure shows a more detailed IR configuration of each of the image forming units Pa, Pb, Pc, and Pd included in the IR system. As mentioned above, each image forming section Pa, P
Since b, Pc, and Pd have the same configuration, the image forming section Pa will be described here. image form f
As already mentioned, the & section Pa consists of the optical scanning device 3C, the photosensitive drum ]C, and the surrounding area a1. The optical scanning device 3C is rotatable as a whole in the direction of the arrow in FIG. It is freely supported. The optical scanning device 3C is equipped with F! 1
The stepping actuator 41, which is fixed to the main body (not shown) and whose drive shaft tip end side presses against the main body 23 of the optical scanning device 213G by a spring or the like, is driven, so that the entire body, centered on the two sleeves, moves as shown in the arrow. The inclination of the scanning line is thereby adjusted. Optical scanning device 3C
, the stepping actuator 40 whose driving shaft end side is in pressure contact with the optical scanning device 2t3G main body 23 by a tongue spring or the like fixed to the main body (not shown) is shown in the arrow a1. By driving in the a-z direction.

The entire body reciprocates in the direction of arrow (a) along axis 2 as shown in the figure, thereby changing the optical path of the scanning light (
The magnification of the rii image is adjusted by varying the distance between the optical scanning device 7113c and the photosensitive drum 1C. The optical scanning device 513G.

h In addition to each member described above, the main body 23 of the optical scanning device 213C
A laser light source 22 provided at one end of the main body 23 at a predetermined position and a light beam L irradiated from a laser light source z2 provided at a position δ facing the laser light source 22 at the other end of the main body 23 are reflected and scanned. a polygon mirror 21 provided in the device main body 23 to reflect and scan the light beam L from the polygon mirror 21;
The light beam L passing through the θ lens 20 and 20 is guided to a predetermined position η on the external surface of the photosensitive drum IC.

Em 3 shows a more detailed configuration of the image forming section, signal processing system, etc., focusing on the number of mark reading copies that the image forming apparatus according to the embodiment of the present invention shown in FIG. 1 has. It is something. As mentioned above, each mark reading device fi 24] 24L is a mirror image and has the same configuration, so here, the mark reading device 21
Housing 124 formed as described for 24H
, a CCD line sensor 33 as a light receiving section attached to the back side of the housing 124, and the housing 12.
A lens 31 serving as a detection unit is attached to the entrance side of 4.
, an infrared transmission filter 32 provided near the CCD line sensor 33 between the CCD line sensor 33 and the lens 31 in the housing 124, and the housing 1
24 is driven in a step before executing the image forming process, and illuminates the detection area on the outer circumferential surface of the transfer material conveying belt 6. @Note CC
The D line sensor 33 is connected to each of the photosensitive drums IC to IB.
The four registration marks 15R transferred from K onto the transfer material conveying belt 6 in the manner described above are detected by the mark reading device f.
The light scattered from the registration mark 15R reaches the positioning mark reading area where the registration mark 15R is provided, and is focused by the lens 31 and focused by the sensor 33E via the infrared transmission filter 32. A heat signal corresponding to the registration mark 15R is output. Since the transfer material conveyance belt 6 is made of a transparent material, almost no light from areas other than the registration marks 15R enters the CCD line sensor 33.In addition, in the wooden embodiment, Ir, By providing the outer band transmission filter 3z, the detection intensity of II★ scattered light from the cyan registration mark 15R, magenta registration mark i5R, yellow registration mark, and black registration mark 15R is made as uniform as possible. However, it is possible to detect each of the registration marks 15R without providing the infrared transmission filter 32.

The signal processing system includes a signal processing circuit 34 that receives the @ signal output from the CCD line sensor 33 of the mark reading device '1124R, and a laser drive whose drive is controlled by the output signal from the signal processing circuit 34. It consists of a circuit 35 and an actuator drive circuit 36. The laser drive circuit 35 controls the laser light source 22 shown in FIG. 2 based on the drive command signal output from the signal processing circuit 34.
#JA operation/stop, or laser light source 2
The timing of light emission of the second light is changed by ηf. The actuator drive circuit 36 is the signal processing circuit 3! The stepping actuator 40 or stepping actuator 41 shown in FIG. 2 is driven/stopped based on the drive command signal outputted from the drive command signal, and thereby the inclination of the scanning line can be checked! (ffjl et al., mechanical minute changes in the optical path of the light beam L irradiated from the optical scanning device) or the magnification of the image formed on the photoreceptor drum 2.
It is configured to adjust A. The signal processing circuit 34 is
Based on the registration mark 15R detection signal output from the CCD line sensor 33, the four types of image transfer misalignment (namely, top margin misalignment, left margin misalignment, f-line blur misalignment, and magnification misalignment) are detected based on the registration mark 15R detection signal output from the CCD line sensor 33. ) is occurring. The signal processing circuit 34 pJc-1
As a result of 4-cutting, if it is recognized that it corresponds to any one of the four types of image transfer misalignment described in E, it is determined according to the mode of the misalignment and the total n value of the amount of misalignment between each registration mark. In order to perform image position correction, the laser drive circuit 35
．． 7 so as to output a drive command signal to the cutter drive circuit 36! ! has been completed. In this embodiment, as is clear from FIG. 1, cross-shaped registration marks 15R and 15L are used, but it is difficult to detect deviations in two directions at once. If possible, use a resist mark 15R with a shape other than a cross.
, it is not supported even if it is adopted in 15L.

FIG. 4 shows a more detailed circuit configuration of all signal processing circuits included in the image forming apparatus (according to one embodiment of the present invention shown in FIG. 3).

As is clear from FIG. 4, the signal processing circuit 34 described above includes amplifiers 101, 103, a binarization circuit 105,
107. Main scanning synchronization signal generator! 1109, exclusive logic circuit (EXI) 117. Scanning line slope control circuit 111, top margin control circuit l13, and left margin control circuit/
It has 41 components including a magnification control circuit 115. The above-mentioned M formation will be explained in more detail as follows.

That is.

Does the amplifier 101 read marks? Place the 24R CCD line below simply rCcD33RJ,! It amplifies and outputs the extremely low level detection signal of the registration mark 15R output from the i6.1flvA unit 103t*, the take reading Rff124, which is a register output from the LCD line sensor 33 (hereinafter simply referred to as rCCD33L). The extremely low level detection signal of the mark 15L (!D is also an electrical signal corresponding to the exact position of the resist mark 15L) is amplified and output. The binarization circuit 105 converts the analog signal output from the amplifier circuit 101 into a digital signal, and then outputs the digital signal COD IF. 2
The v4 conversion circuit 107 converts the analog signal output from the amplifier circuit 103 into a digital signal, and then outputs the digital signal CCD2F. The main scanning synchronization signal generator 109 generates one main scanning period signal at preset time intervals, and transmits this signal to the CCD 33R, CCD 3
3L, scanning line #1 control circuit 111. Exclusive OR circuit (EXI) 117. ) Tube margin control circuit l1
3 and the left margin control/magnification control circuit 115. Exclusive OR circuit (EXI
) 117 is a CCD output from the binarization circuit lO5
The 1 p signal and the 1 main scanning period signal outputted from the main scanning synchronization signal generator δ109 are exclusive ORed to output a start 1 signal. As is already clear from the contents of *j, the aforementioned left margin control circuit 115 corrects the left margin shift or magnification shift when the transferred image has a left margin shift or a magnification shift. (2) Starting from 123, counter (3)
125. Comparison circuit 127. Comparison circuit 129 and MPU
(2) It is composed of 131. Counter (2) 1
23, the point in time when the l main scanning periodic signal is outputted as described above from the main scanning synchronization signal generation bag 2t109 is the starting point, and the point in time when the CCD' l F signal is outputted from the binarization circuit 105 is the point in time to end. The clock signals applied from the outside are counted between the time points. The counter (2) 123 includes a clock terminal that receives an
A start terminal that receives the l main scanning periodic signal output from the 1109, and a COD output from the binarization circuit 105.
The stop terminal that receives the IF signal and each image forming section Pa-Pd shown in FIG. 1 are connected to the I! ! It has an E terminal for receiving a station select signal applied for selecting the station, and an output terminal for outputting the count value t+ of the X1 clock counted during the above-mentioned time period. Counter (3) 125 also has the same configuration as counter (2) 123.

The time when the main scanning synchronization signal generation bag 3109 outputs the 11-scanning cycle signal as described above is the start time, and the time when the cco2p@ signal is output from the binarization circuit 107 is the end time. It is designed to count the clock signals that are input. The counter (3) 125 has a clock terminal that receives the Xi micro clock signal set to a high frequency, a start terminal that receives the l main scanning periodic signal output from the main scanning synchronization signal generator 109, and the z value conversion circuit 107. A stop terminal that receives the C0D2F signal output from each image forming section Pa-P shown in FIG.
The stage provided for selecting d has an E terminal for receiving a select signal, and an output terminal for outputting the count value tl of the X1 clock counted between the above-mentioned time points. The comparison circuit 127 calculates in advance the count value t of the X1 clock output from the counter (2) 123 (the time difference value between the output time of the l main scanning period signal and the output time of the detection signal from the CCD 33R). The reference value to (also referred to as the center value to) is set as a reference value to (also referred to as the center value to), which is determined by one main scanning period signal when the transferred image is always transferred to the correct position without deviations such as left margin deviation or magnification error deviation. The time difference value between the reference time point and the time point when the detection signal is output from the CCD33R133L is compared with the reference time point when the detection signal is output from the CCD33R133L, and the difference value Δti between tl and to is output. It is supposed to be done. The comparison circuit 129 calculates the count value t of the X1 clock output from the counter (3) 125.
z (is the output point of the main scanning period signal and COD 33
time difference value between the output point of the detection signal from L), and
tz is calculated by comparing with the preset standard flto.
The difference value Δtz between and to is output. M
The PU(2) 131 has a magnification error diameter preset according to the magnitude of the difference value Δt1 outputted from the comparison circuit 127 and the magnitude of the difference value Δt outputted from the comparison circuit 129. It has two storage areas that separately store ghf data and left margin shift movement amount data. The MPU (2) 131 has an S terminal that receives a stage selection signal applied to select each of the image forming units Pa to Pd shown in FIG. MPU (2) 131 is the 1 magnification control value output terminal 27
It has C127M, 27Y, 27BK, and
Left margin control signal output terminal delay (CM),
Dishii (MH),
Dayley (YH), Dayley (BK)
) also has I). The MPU (2) 131
a station select signal given through the terminal;
Since the difference values Δ1+ and Δt are output from the comparator circuit 127 and the comparator circuit 129, respectively, either the left margin deviation movement amount data or the magnification error movement amount data is read out, and the In order to drive the stepping actuator 40 of the image forming section selected by the stage select signal, the drive command signal is output to the actuator drive circuit 36 shown in FIG. As is already clear from the above-mentioned content, the top margin control circuit 113 corrects the top margin shift when it occurs in the transferred image.
, a sub-scanning synchronous counter (M) 135. Sub-scanning synchronous counter (Y) 137, sub-scanning synchronous counter (B
K) 139 and MPU (3) 141. The sub-scanning synchronous counters (C) 1'33 to (BK) 139 each have the same configuration.1 For example, if we describe the 6 sub-scanning period counter (C) 133, the counter (C) is , the start point is the time when the resistor/7 old signal C given from the outside is input, and the end point is the time when the start l signal is input from the exclusive OR circuit (EXI) 117. The main scanning synchronization signal generator? One main scanning period signal outputted from 1109 is counted. Sub-scanning synchronous counter (C) 1
33 outputs the count value C'.

The sub-scanning synchronous counter (C) 133 has a clock terminal for receiving a 17-scanning cycle signal outputted from the main-scanning synchronizing signal generator 109, and a start terminal for receiving a registration mark filling-in signal C transmitted from the outside. It has a stop terminal that receives the start 1 signal output from the exclusive OR circuit (EXL) 117, and an output terminal that outputs the aforementioned count fIIC'. In addition, in place of the one main scanning period signal inputted to the clock terminal, other sub-scanning synchronous counters (M) 135 to (
A description of the configuration of BK) 139 will be omitted. MPU
(3) 141 is each image forming unit Pa shown in FIG.
-Pd$-A stage provided for selection, has a terminal for receiving a select signal. MPU (3)1
41 is a top boogin control signal output terminal delay (C
), Daylay (M), Daylay (Y), Daylay (B
K). MPtJ (3) 141 are registration mark write signals C, M, Y, BK given from the outside.
Registration mark position data obtained when each registration mark 15R, 15L is accurately aged at a predetermined position a on the outer surface of the transfer material conveying belt 6 based on the above is stored in advance. The MPU (3) 141 receives a stage select signal applied via the terminal and each image forming unit P&~ read based on the stage select signal.
The sub-scanning synchronous counter (C) 133 corresponding to Pd
- (BK) 1 from the count value given from any one of the sub-scanning synchronous counters of 139 and the data of the image forming unit that corresponds to the count value read out from the data stored in advance. A top margin control signal is output to perform correction according to the amount of top margin deviation of the generated transferred image. The scanning line slope control circuit 111 is.

As is already clear from the above content, this is a method for correcting scanning line inclination deviation when it occurs in a transferred image,
Starting with the exclusive OR circuit (EX2) 119, the counter (
1) 121. MPU (1) 143 and selector 145
have. The exclusive OR circuit (EX2) 119 is
l main scanning periodic signal output from main scanning synchronization signal generator 109 and C0D2F output from binarization circuit 107
A stop 2 signal is output by performing an exclusive OR with the signal. Counter (1) 121 is.

The time when the CCU 33R outputs a detection signal by detecting the registration mark 15R formed on the transfer material conveying belt 6 by each image forming unit Pa-Pd, and the time when the CCU 33R
3L detects the registration mark 15L corresponding to the detected registration mark 15H and outputs a detection signal, and calculates the time difference value between the time when the registration mark 15L outputs the detection signal, and the value obtained by the calculation is set as the scanning line slope IN. This is what is output. In order to obtain the scanning line inclination amount N, the counter (1) 121 starts at the time when the start 1 signal is output from the exclusive OR circuit (EXI) 117, and starts the exclusive OR circuit (EX2) 1. .19, the point in time when the stop 2 signal is outputted is the end point, and one main scanning period signal outputted from the main scanning synchronizing signal generator 109 during that point in time is counted. The configuration of counter (1) 121 is as follows: counter (2) 123 and counter (3) described above.
125, detailed explanation thereof will be omitted.

The MPU (1) 143 stores scanning line tilt amount correction value data that is set in advance for each image forming unit Pa to Pd in stages according to the magnitude of the predicted scanning line tilt amount N. . The MPU (1) 143 calculates the scanning line inclination YN for each of the image forming parts Pa-Pd output from the counter (1) and the correction value set for each of the image forming parts Pa-P'd. A scanning line tilt amount correction value for each image forming unit is determined from the data, and a drive command signal is output to the actuator drive circuit 36 via the selector 145 to drive the actuator 41 based on the determined correction value data. It is composed of The selector 145 selects the MPU (1) 1 based on a stage select signal received from the outside.
The scanning line inclination correction value of the image transferred from the image forming section corresponding to the select signal outputted from the image forming section 43 is outputted to the 7-processor drive circuit 36 of the image forming section. receiving terminal and control 1 signal output terminal 28G, 29C, 28M, 29M, 28Y, 29Y,
It has 288K and 29BK.

Note that one main scanning period signal output from the main scanning synchronization signal generator 21109 is generated by the CCD 33R, C
The signals are also supplied to the CD 33L, so that the generation timing of the image signals outputted from the CCD 33 R1 and the CCD 33L to the amplifiers IOT and 103, respectively, is matched to the period of the main scanning period signal. ing.

The above-mentioned CCD33R133L are each installed at a predetermined position according to standard 1.2 shown in FIG.
When the registration mark 15R115I is formed at a regular position that is more accurate than the reading start reference position and has no scanning line inclination 1 magnification error, the center of the registration mark L5R, 15L is read at the center pixel of M'X of the CCD 33R133L. The system shall be configured in such a way that it is possible to do so. Also, the main scanning start position of each CCD33R133L! (Left margin) also starts from the standard 1.2 of the CCD.
It is assumed that directions 33R and 33L are set.

Figure 5 shows an example where transfer deviations such as double:$M difference deviation and left margin deviation occur in the images transferred from each image forming unit Pa-Pd, and an example where an image is formed at a regular position without transfer image deviation. This is an example of what was done. In FIG. 5, the image IA (which may be considered as a registration mark 15R) having a substantially doglegged shape indicated by a solid line is an image formed at a regular position without transfer misalignment on the transfer material S, etc. can be,
In addition, the image IB exhibiting a dogleg shape indicated by the uI line
The image (which may be considered as the registration mark 15L) is an image formed on the transfer material S or the like with a defect such as a magnification error shift or a left margin shift. Now, let's pretend that the picture is f&lA
is moved in the direction of the arrow in FIG. 5 (downward in FIG. 5) by the transfer material conveyance belt 6 and passes through the detection areas of CCD 33R and CCD 33L, an image signal indicating that CCD 33R has detected image IA, that is, detection The time when the signal is output (that is, the time when one main scanning period signal is output), the time when the time t has elapsed as the start of the detection, and the following.

The time to' (represented by time toJ) and the output timing of the detection signal, that is, the image signal indicating that the CCD 33L has detected the image IA (in other words, the detection start time is the time when one main scanning period signal is output), and the time to' The elapsed time point (hereinafter expressed as "time t O'J") coincides with the time to' (respectively shown on the time axis 3A in FIG. 5). Therefore, the image LA has no transferred image shift. In other words, the reference position for starting writing of the image transferred by the image forming section onto the transfer material S of the transfer material conveying belt 6-F is the reference position indicated by the reference numeral 2 in FIG. position.On the other hand, 1
Assuming that image IB passes through the detection areas of CCD 33R and CCD 33L, the output time of the detection signal indicating that CCD 33R has detected image IB, that is, the image signal, is t1.
=to, but the output time of the detection signal, that is, the image signal output from the CCD 33L is 1. is t z < t O”
Since it is clear from the figure that t and >tz (respectively shown on the time axis 3B in FIG. 5), the image IB has the transferred image shift (f8 rate reduction etc.) is occurring. In other words, the starting reference position of the image transferred to the transfer material S etc. by one image forming section is too far inward in FIG. It becomes necessary. Therefore, in order to eliminate the above-mentioned problems, it is necessary to increase the magnification and also shift the foot margin shift from the position indicated by 2A to the position indicated by 2B.

During the control operation of the signal processing circuit 34 configured as described above, especially the magnification! ! ! Control operation and scanning line inclination for correcting differential left margin deviation! ! The control operation for correcting the amount is performed in the sixth
The following description will be made using timing charts shown in the figures.

(B) Control operation for correcting magnification error and left margin deviation As is clear from FIG. 6, the main scanning period signal mentioned above has a period as shown on the time axis. In the 8-hour region (1) to be output, the CCD
33R1CCD33L both have registration mark 15R
115L is not read, each of these CCD33
No detection signal, that is, an image signal is output from R, 33L (sixth factor time axis ■, @ Teru Tani). When moving from time domain ■ to time domain ■, CCD33R outputs the first image type main scanning period signal. Time 1. After the elapsed time, an image signal is output. As described in FIG. 5, if the registration mark 15R is formed at a regular position, t,=to
It is clear that when we move from the 9-hour domain (■) to the time domain (■).

The CCD 33L detects the registration mark 15L (corresponding to the registration mark 15R) formed by the first image forming section Pa, and waits for 1 hour f! As shown in ll■, the time tz has elapsed since the third 1st main scanning period signal was output.
After the elapsed time, an image signal is output. As described in FIG. 5, it is clear that the registration mark 15L is formed at a position deviated from the normal position, and moreover, to>
The relationship tz holds true. In the time domain (■), the counter 9125 counts x1 (time! Said time t
The x1 clock (shown by time axis ■ in FIG. The value of to is compared (1,=10) (time axis ■), and the comparison circuit 129 compares the value of tz with the value of to (ΔLz''-1) (time axis ■). ) As a result, magnification error correction and left margin shift correction are performed as described above. 1; The above-mentioned correction is performed in the same manner for 1 image form I & portion Pb-Pd.

(b) it/Iu4 operation for correcting the amount of scanning line inclination;
In the above-mentioned time domain (■), as the C0D33R reads the registration mark 15Rt-, the exclusive OR circuit (EXI) 117 outputs the start 1 signal (time axis (Φ
) is output, the counter (1) 121 is
1 Counting of the main scanning period signal is started, and in the time domain (), the CCD 33L reads the registration mark 15L corresponding to the registration mark 15R, so that the exclusive OR circuit (EX2) 119 outputs stop 2.
The above counting operation is continued until a signal (indicated by time axis 0) is output. The count value obtained by the above-mentioned counting is outputted from the counter (1) 121 as the scanning line inclination amount N (in this embodiment, N=1) as shown by 1 on the time axis, and thereby the scanning as described above is performed. Line slope amount correction will be performed. The above-described correction is similarly performed for ifj image forming sections Pb-Pd.

The timing at which the above-described correction is performed will be further explained as follows. That is, if the above-described correction is to be performed each time one image forming process is executed, the registration marks 15R and 15L are transferred onto the transfer material conveying belt 6, the transfer position is detected, and the The process of starting the image forming process after (or during) the above-described control operations are performed based on the detection is repeated each time. Therefore, a problem arises in that there is a long period of time between when the image forming device is activated and when a transferred image is obtained. So, in order to solve this kind of problem.

If the detection operation of the registration marks 15R and 15L and the correction operation associated with the detection are performed at the time of setting up the apparatus or after turning on the drive power of the apparatus and during warm-up, etc.,
By controlling the drive of the transfer material conveyance belt 6 and the photosensitive drum ICI BK, it is possible to stably maintain good image quality of f+1', so that transfer can be performed without requiring extra time. Images with almost no deviation etc. can be obtained at all times.

The above-mentioned J8Ij image forming apparatus is designed to shut off the drive power when an abnormal operation such as a paper jam occurs, or when replacing the unit or unit during maintenance, etc., for safety reasons. After the drive power is turned on again, detection and correction operations for the registration marks 15R and L5L are automatically executed to prevent transfer misalignment caused by the operations described in -1-. ing. Furthermore, -h
Record? Inside the c21, there are sensors that detect shocks applied from the outside and sensors that detect changes in the environment, etc. When a transfer misalignment occurs due to ie or environmental changes, the above configuration corrects the transfer misalignment.

As a result of prototype production and use of the image forming apparatus according to the embodiment of the present invention described above, it becomes possible to automatically and quickly correct transfer misalignment of both images caused by various factors, and it becomes possible to correct misalignment of one color or hue. I was always able to obtain high-quality, full-color images without any changes such as Since the above-mentioned equipment has an automatic correction function as mentioned above, the mechanical-optical ratio during product assembly can be adjusted to some extent in the adjustment stage.
It is now possible to widen the adjustment tolerance range, thereby saving labor and shortening work time.
In addition, it has become possible to perform highly accurate correction without placing any additional burden on users, service personnel, etc. In the above-described embodiment, an image forming apparatus is described in which four image forming sections are provided, but the number is not limited to four, and the image forming apparatus may include a plurality of image forming sections. The invention can be applied to any type of image forming apparatus. In this embodiment, the mark reading device 24R224L uses a CCD line sensor 33, but an area type CCD
It is also good to adopt.

It is also possible to adopt a phototransistor array.9 In this embodiment, when a deviation occurs in the registration mark 15R115L, in order to correct the amount of deviation, the emission timing and optical path of the laser light source 22 are feedback controlled. However, the driving of the photosensitive drum IC-IBK and the driving of the transfer material conveying belt 6 may also be controlled.

In the embodiment described above, the mark reading device! ! 24R6
An illumination section and a detection section constituting 24L were both disposed on the side of the transfer material conveying belt 6 on which the image was transferred. Mark reading device 2124R124L with such a configuration
In this case, among the developer transferred to the transfer material conveying belt 6 J: and the transfer material SL adsorbed to the conveying belt 6, the developer floating in the air due to scattering is exposed to the illumination lamp 30.
The lighting lamp 30 adheres to the surface of the lamp and gradually accumulates.
When the developer is deposited on the surface of the registration mark, the amount of light becomes insufficient and the level of the registration mark detection signal decreases, causing a problem that detection becomes difficult. In addition to the above problem, it is necessary to loop the transfer material S on the transfer material transport belt 6 immediately after the image forming portion Pd when the transfer material S is separated from the transport belt 6 and guided to the fixing device, so a certain amount of space is required. Therefore, it is necessary to increase the amount of light from the illumination lamp 30, but this increases power consumption and also prevents the illumination lamp 30 etc. from approaching the conveyor belt 6.
Problems such as adversely affecting BK also arise. Therefore, the mark reading device mentioned above! t24R.

A prototype image forming apparatus was fabricated using 24L as described below.

FIG. 7 shows an image forming apparatus according to another embodiment of the present invention. In FIG. 7, the same components as those in the first embodiment described above are given the same reference numerals. Registration mark 15R, 1
The detection of 5L is performed using the image form E & part Pd as in the IT embodiment.
It is done immediately after. The illumination section is opposed to the detection section 1 with the transfer material conveyance belt 6 interposed therebetween. The illumination section is connected to the detection section and the side where the transfer material stagnant feeder J Retro's FIi wire is transferred (
In other words, it is disposed close to the transfer material conveying belt 6 on the side opposite to the outer peripheral surface (that is, the inner peripheral surface). The lighting department.

It has a Kohler type illumination lamp 30, a cover 37 that covers the light emitting part of the illumination lamp 3°, a diffusion plate 38, and an infrared transmission filter 32. On the other hand, the detection part is not equipped with a filter, and the inner surface of the cover 37 is coated with a coating with a high reflectance of 1, and the -1- surface is coated with a registration mark 1.
It has an opening for irradiating light beams to 5R and 15L, and the above-mentioned diffusion plate 38 and infrared transmission filter 32 are fitted into the opening. The light from the illumination lamp 30 illuminates the detection position of the conveyor belt 6 as diffused infrared light. The reason why the Kohler type illumination lamp 30 was used as the illumination lamp 30 was to make the illuminance distribution uniform in the detection range, and the reason why the cover 37 was attached was to prevent the light from being emitted to the photoreceptor drum Ic-IBK. This is to defend as much as possible.

With the above-described configuration, the transfer material WI with a high rate of light rays
It passed through the feed belt 6 (in the unexampled example, an infrared light transmittance of 90% was used) and hit the registration mark 15R215r from the side! l! 1 civilization enters the detection unit. The light incident on the detection unit 1 is focused on the CCD line sensor 33 via the lens 31.

Unlike the case of the first embodiment described above, since the transmitted light transmitted through the transfer material conveying belt 6 is detected, the background area side becomes brighter, while the registration mark 15R1
The portion 15L is detected as a shadow due to absorption or reflection of light. Therefore, in terms of signal processing,
There will be some parts that are opposite to the embodiment.

According to the device configured as described above, there is no possibility of low light output in the illumination section due to scattered toner, and it is possible to always detect the registration marks 15R115L in a good condition, improving durability and reliability. sex has improved. or,
g. Because the use section is arranged on the inner circumferential side of the transfer material conveying belt 6.

When the rolling f-material S enters the constant R device, it becomes easier to secure a space to create the necessary loop, and the lighting lamp 3
0 can be easily brought close to the 6 surfaces of the transfer material conveying belt, making it possible to increase the amount of light per area by about 1wL, which allows for stable high-quality image formation. became.

In the two embodiments described above, the moving member that passes near the transfer area in the image forming apparatus has been described as the transfer material conveying belt 6, but it may also be the transfer material S itself, and furthermore, the moving member passing near the transfer area in the image forming apparatus may be the transfer material S itself. Of course, the same effects as in the above two embodiments can be obtained even with the intermediate transfer body in which each image is multiple-transferred to the intermediate transfer body and then re-transferred to the transfer material S all at once. .

As explained above, according to the present invention, a professional engineer such as a service person can electrically adjust the timing deviation of image Wj formation, and the machine front of the 8 image forming sections can be adjusted. ! Due to various reasons, there may be a shift in the timing of one image formation in the ridge where the adjustment has been made, or each image W! Even if a 5-minute collision occurs due to a discrepancy in the mechanical position of the parts, the above-mentioned problem will be automatically resolved without the need for specialized technical staff such as service personnel. Accordingly, it is possible to provide an image type Ti device that can obtain images with good image quality without transfer deviation or image deviation.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the overall configuration of an image forming apparatus according to the invention. FIG. 2 is a perspective view showing an image forming section included in an image forming apparatus according to the present invention. FIG. 3 is a diagram showing the detailed configuration of the image forming section and the signal processing circuit, etc., centering on the mark reading device included in the image forming section according to an embodiment of the present invention. . FIG. 4 is a block diagram 7) showing a more detailed circuit configuration of the signal processing circuit included in the image forming apparatus according to the embodiment of the present invention shown in FIG. 3. FIG. 5 is an explanatory view of the construction of an image type lJt neck attachment according to an embodiment of the invention. FIG. 6 is a timing chart showing the operation of a signal processing circuit included in an image forming apparatus according to an embodiment of the present invention. FIG. 7 is a diagram showing a detailed configuration of one image forming section, a signal processing system, etc. centering on a mark reading device included in an image forming apparatus according to another embodiment of the present invention. FIG. 8 is an explanatory diagram showing the transfer image shift. 6: Transfer material conveying belt 24R124L+2- Bubble reading device Pa, Pb, Pc, Pd: Image forming unit FIG. 2 FIG. 3 FIG. 5 A 38- Pipe-work 111 (a) (b) A A - [-1
- life plan (c) (d)

Claims (1)

[Claims] 1) A plurality of image forming units that form visible images corresponding to document image information and also form visible images of position detection marks, and a plurality of image forming units that form visible images corresponding to document image information formed by the image forming units. a moving member that sequentially moves and passes through a transfer area that transfers the image or the visible image of the position detection mark;
position detection mark detection means provided on the downstream side in the moving direction of the moving member in the transfer area and detecting the position detection mark transferred onto the moving member, An image forming apparatus according to claim 1, wherein each of the image forming units is controlled to correct a transfer image shift based on a detected signal.