JPH10190975A - Image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically correct resist deviation and to improve image quality by reading a specified pattern, computing the resist deviation of copy images from the read specified pattern and correcting it. SOLUTION: By the passing of a copied form through read units 501 and 502 at the time of re-feeding paper, the specified pattern of a copy surface is read. On the surface of a copied form 505, a copied yellow specified pattern is formed. The difference in the dot of the specified pattern and a reference dot is detected, and write reference signals are corrected by the start timing of a main scanning and sub-scanning. The images are written to a photosensitive body at a corrected timing. The resist adjustment of the main scanning and the resist adjustment of a sub-scanning direction are corrected by changing the resist timing of write. That is, the resist deviation of the copy images is computed from the read specified pattern and corrected. Thus, resist is arranged, and the image quality is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image processing apparatus applied to a digital copying machine or the like.

[0002]

2. Description of the Related Art Conventionally, some image processing apparatuses have a duplex copying function. In addition, remarkable progress has been made in the improvement of image quality and colorization of copiers. In order to prevent unauthorized copying of securities, banknotes, etc., along with these multi-functionality and high functionality, a device-specific pattern is added to the copy to identify the device used for unauthorized copying from the unauthorized copy, A measure is taken to add information that can identify the person who made the illegal copy to the copy.

[0003] As a specific conventional example similar to the technical field of the present invention, there is an "image processing apparatus" of JP-A-4-294682 of prior art 1. The purpose of this conventional example is to specify an image processing apparatus from a reproduced image by adding a specific pattern that is difficult to be recognized by human eyes to an output image signal. In the configuration of this conventional example, the AND gate of the pattern addition circuit takes the logical product of the inverted signal of the upper bit CNO1 and the lower bit CNO0 of the 2-bit field sequential signal, and sends it to the AND gate. This is a signal effective only when CNO = 2, that is, only when the image is currently printed in yellow. On the other hand, the register holds the values of P1 to P4 in advance and stores the pattern level selection signal P from the CPU.
According to S, one of P1 to P4 is selected, a pattern is added to the input signal V by the adder via the gate, and V 'is output. The resolution is 400 dpi, and a pattern is added every 32.5 mm. However, since Japanese banknotes are 76 mm wide and banknotes in major countries are approximately 60 to 120 mm, this pattern is always added to the inside when copied. It is possible to specify the machine number of the copying machine used in the above.

Japanese Unexamined Patent Publication No. Hei 4-294682 discloses a technique for adding information such as the machine number of a copying machine to a copy sheet in a specific pattern that is difficult to recognize by human eyes.

Japanese Unexamined Patent Publication No. 5-244389 of the third prior art discloses a technique in which a data is detected adjacent to a place where a specific pattern is to be added, but the data is detected, and the pattern is further complementarily added so as not to be noticeable. ing.

Further, Japanese Patent Application Laid-Open No. 5-244390 of prior art 4
Japanese Patent Application Laid-Open Publication No. H11-163873 discloses a technique of detecting pixel data at a location where a specific pattern is to be added, and changing the color of the specific pattern so as to be identifiable without deteriorating the image quality.

[0007]

However, in double-sided copying of an image processing apparatus, it is very difficult to align the front and back resists. In black and white text originals, even if the front and back are not overlapped, this did not cause a serious obstacle. However, in color originals, misregistration did not occur, and white spots would shift. Due to the occurrence of this phenomenon, show-through occurs at the end, which may be a user complaint. Further, in a copy to which a tracking pattern has been added, it is required to recognize the tracking pattern and correct the registration to improve the image quality.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image processing apparatus which automatically corrects a registration error and improves image quality.

[0009]

According to an aspect of the present invention, there is provided an image processing apparatus comprising: a function unit for adding a specific pattern to a copy image and transferring the pattern to a copy sheet; And a functional unit for calculating and correcting the registration error of the copy image from the specific pattern read.

Further, the function section for reading the specific pattern may be provided in the manual sheet feeding section.

The image processing apparatus according to the third aspect of the present invention provides
A function unit for adding a specific pattern to the copy image and transferring the copy sheet to a copy sheet, a reversing unit for reversing the discharged copy sheet and feeding the same again, a function unit for reading a specific pattern, It is characterized in that it has a calculation unit for calculating the registration shift of the copy image from the pattern, and a function unit for correcting the position of the image formed on the back surface of the copy sheet based on the calculation result.

The function section for reading the specific pattern is provided in the main body sheet feeding section, and the function section for correcting the image position performs registration adjustment in the main scanning direction and the sub-scanning direction by adjusting writing timing. Alternatively, registration adjustment in the sub-scanning direction may be performed by adjusting the timing of sheet feeding.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of an image processing apparatus according to the present invention will be described in detail with reference to the accompanying drawings. FIG.
FIG. 9 to FIG. 9 show an embodiment of the image processing apparatus of the present invention. FIG. 1 is an overall mechanism diagram in which the present embodiment is applied to a digital full-color copying machine. An embodiment of the present invention will be described using this digital full-color copying machine.
However, application to other devices such as a color printer that performs similar image processing is also possible.

The function of the scanner module 200 shown in FIG. 1 can be roughly divided into image reading means 250 for reading an original image by dividing it into pixels, basic image processing means 300,
The DC power supply 201 includes an extended image processing unit 350, a first communication control unit 230, and a power receiving plug 201P.

(Mechanical Configuration of Scanner Module 200)
In FIG. 1, reference numeral 201 denotes a DC power supply device serving as a first power supply unit; 201P, a power plug for connecting a commercial power supply;
SW is a power switch, 202 is platen glass, 202
S is an image tip reference position, 202SH is a shading correction white plate, 202B is an individual identification barcode plate, 208
Is a first carriage, 209 is a second carriage, 203 is a document illumination lamp, and 204A, B, and C are first, second, and
A third mirror, 205 is an imaging lens, 205X is a lens optical axis, 207 is a color imaging device, 211 is a carriage home sensor, 230S1 and 230S2 are on the first communication control means 230 and have the same shape and the same interface. SCSI connectors, 230F1 and 230F2 are optical fiber connectors for scanner selective additional device communication, 250
Is a circuit board on which the original image reading means is mounted, 300 is a circuit board on which the basic image processing means is mounted, and 350 is a circuit board on which the extended image processing means is mounted.

(Configuration of Image Reading Unit 250) In FIG. 1, the image reading unit 250 includes an analog / digital converter (hereinafter, A / D converter) (not shown), a shading correction circuit, It has a displacement compensation circuit and the like.

The original 180 is placed on the platen 202 such that the copy surface is down and the reading start position is at the left end 202S of the platen. The imaging lens 205 forms a reduced projection image of the original image on the light receiving surface of the imaging device 207. The imaging device 207 is a charge-coupled device (CCD) and has a color imaging function, and an R imaging unit having a one-dimensional array of 4752 pixels covered with a red filter and a G imaging unit having a one-dimensional array of 4752 pixels covered with a green filter. 4752 covered with blue filter
The B image pickup unit in which pixels are arranged one-dimensionally has a structure in which three rows are arranged in parallel in the main scanning direction (vertical direction on the paper surface of FIG. 2). The three scanning lines are almost close, specifically, equivalent to an interval of 4/16 mm in terms of 180 original images. The scanning direction of the one-dimensional imaging device is referred to as main scanning, and the direction orthogonal thereto is referred to as sub-scanning.

The illumination lamp 203 and the first mirror 204A are mounted on a first carriage 208, and the second mirror 204
B and the third mirror 204C are fixed to the second carriage 209. When reading the original image, the first carriage scans at the sub-scanning speed Vsub, and the second carriage scans at the speed of Vsub / 2 from the left end to the right end while maintaining the optical conjugate relationship by the original image scanning motor 210 and the driving wire 210W. (Sub-scan) is driven. As the motor 210, a stepping motor is used. The sub-scanning speed Vsub is variable from 1/8 to 4 times the reference speed in steps of 1%, and an arbitrary speed is selected by a command from another module.

(Operation of Image Reading Means 250) The first carriage 208 is stationary just above the normal carriage home sensor 211 and stands by. The sensor output at this time is O
N. When the scan command SCAN or REQ is received, the lamp 203 is turned on at t1 and the motor 210 is turned on.
To start scanning rightward. After the time t2, the carriage 208 goes out of the detection range of the home sensor 211, and the output is turned off. The deviated position is stored as a scanning reference position and used as a position calibration reference point. Also the first
The communication control unit 230 calculates an optimal acceleration plan to achieve the arrival time t5 to the image front end 202S and the required accuracy of the speed Vsub, and calculates a step pulse train of the motor 210. Thereafter, the carriage speed is driven by this pulse train, and the time to reach the image front end 202S and the desired constant speed scanning are achieved as expected.

After passing through the calibration reference point, the imaging device 207 reads an image of each color projected by the lens 205 in units of main scanning lines regardless of the sub-scanning speed. This is convenient for keeping the charge accumulation time of the imaging device 207 constant. The main scanning cycle is the pulse train cycle ts1 generated by the first synchronization signal generating means 230SYNC in FIG.
The pulse train is read by the reading means 2 via the bus 230BUS.
50. The first synchronizing signal generating means 23
0SYNC is the crystal oscillator 230XT connected here.
The frequency of the original oscillation frequency of L is divided and output to the bus 230BUS. The total number of pixels of the imaging device 207 is 4752, and one line of main scanning is decomposed into 16 pixels / mm in terms of an original image, sampled and read, and an analog voltage corresponding to RGB reflected light in pixel units from the original image 180 is output. . After that, it is converted into an 8-bit digital signal by an A / D converter, that is, 256 bits.
It is quantized to a gradation and passed to the subsequent circuits.

After passing through the reference point, first, at t3, the white reference plate 202SH is read, and an 8-bit digital conversion value is stored in the shading correction circuit. The image data read thereafter is subjected to shading correction effectively. At the time t4, when the carriage 208 passes under the individual identification barcode board 202B for tracking security piracy and providing for remote service, it is read and the image data is transmitted to a system control module (not shown).

Next, at time t5, when the original image tip 202S is reached, the image reading means 250 reads the original image 180 for each scanning line, and outputs color separation digital data 250 for each pixel.
D is sequentially output to the next basic image processing means 300. When the carriage 208 reaches the right end and the time t6 is reached, the motor 210 is turned in the opposite direction, and the home position 21 is read.
Return to 1 and stop, preparing for the next scan.

(Configuration of Printer Module 400) The printer module 400 includes an image forming unit 500, a second communication control unit 430, a power supply unit 401, and a selective adding device. The image forming means 500 refers to an assembly of various image forming elements such as a photosensitive drum 414 for electrophotography, a charging means 419, a laser exposure means 441, a developing means 420, an intermediate transfer member 415, and a second transfer means 427. It is a name.

(Mechanical Configuration of Printer Module 400)
The printer module 400 applied to the present embodiment includes:
Circuit board 43 on which commercial power plug 401P, power switch 401S, power supply means 401, and second communication control means are mounted
0, SCSI connectors 430S1 and 430S2 on the second communication control means 430 having the same shape and the same interface, optical fiber connectors 430F1 and 430F2 for printer selective additional device communication, laser diode 441, fθ lens 442, rotating polygonal surface Mirror 443,
Mirror 444, automatic paper cassette 412 for both-sided copying,
Manual paper feed tray 412B, paper feed rolls 413A and 413B, register roll pair 418R, transport roll pair 4
13F, G, H, J, photoreceptor drum 414, intermediate transfer belt 415, primary transfer corotron 416, secondary transfer corotron 417, charging scorotron 419, and developing devices 42 for cyan, yellow, magenta, and black, respectively.
0C, Y, M, K, developing device assembly 420, cleaner 4
21, a transport belt 422, a fixing roll 423A, a fixing backup roll 423B, a discharge roll 424, a discharge switching roll 425, and an image leading end position detecting unit 426.

(Constituent Elements of Image Forming Means 500)
401P is a commercial power plug, 401SW is a power switch, 430 is a second communication control means, and 430S1 and 2 are components excluding a connector.

(Operation of Image Forming Means 500) The printer module receives the CMY input to the second communication control means 430.
Pixel density of 1/16 for both main scan and sub-scan for each K color
A full-color visible image consisting of a dot pattern with a recording dot density of 1/16 mm or 1/24 mm for each color of CMYK is formed on transfer paper in both main scanning and sub-scanning based on 2-bit recording data of mm or 1/24 mm, and output. I do. Recording dot density 1 / 16mm or 1 / 24m
The selection of the dot m is specified in advance by a mode selection command. The default is a dot density of 1/16 mm.

When the image forming cycle is started, first, the photosensitive drum 414 rotates counterclockwise to the intermediate transfer belt 415.
Is rotated clockwise by the drive motor 414M.
Formation of a C toner image as the intermediate transfer belt 415 rotates,
M image formation, Y image formation, and K image formation are performed, and finally CM
A toner image is formed on the intermediate transfer belt 415 in the order of YK.

First, the C image is formed as follows. The charging scorotron 419 uniformly charges the photosensitive drum 414 with negative charges to -700 V by corona discharge. Subsequently, the laser diode 441 performs raster exposure based on the C signal. A recording signal for image formation is supplied from the scanner module 20 in a general copy mode, and from a system control module (not shown) in a special copy mode including facsimile mode or intelligent mode including intelligent image processing. In the copy mode, a data request signal REQ for "send recording image data after a predetermined time" is issued to the scanner module 200 and to a system control module (not shown) in the printer mode or the facsimile mode.

The recording signal is transmitted to the SC of the second communication control means 430.
The laser drive circuit 441DV, which is input from the SI terminal 430S1 or 430S2 and is a recording control circuit, controls the light emission of the laser diode 441 for each input pixel based on the recording signal. The recording signal is 2 bits per pixel. More specifically, at the time of the highest C density pixel, laser light is emitted for the entire main scanning width, and at the time of a white pixel, no light is emitted. It is like that. When the raster image is exposed in this manner, in the exposed portion of the photosensitive drum 414 which is initially uniformly charged, the charge proportional to the amount of exposure disappears, and an electrostatic latent image is formed.

The toner in the developing device 420C is negatively charged by stirring with the ferrite carrier, and the cyan developing roll 420C of the developing device is
A negative direct current potential and an alternating current are biased by a power source (not shown) to the fourteen metal base layers. As a result, the toner does not adhere to the portion of the photosensitive drum 414 where the charge remains, and the C toner is adsorbed to the portion having no charge, that is, the exposed portion.
A visible image will be formed.

As described above, when the toner image on the photoconductor rotates counterclockwise and reaches the position opposite to the primary transfer corotron 416, the toner image contacts the photoconductor and the intermediate transfer belt 415, which is driven at a synchronous speed, has a corona. Transcribed. Some untransferred residual toner on the photosensitive drum 414 is
14 is cleaned by the cleaning device 421 in preparation for reuse. The collected toner is stored in a waste toner tank (not shown) via a collection pipe.

The intermediate transfer belt 415 is made of a material having a relatively large specific resistance value in order to maintain a long-time image carrying characteristic, which is particularly required in the printer mode. As a result, the toner image can be carried without disturbing the toner image even if the time until the next M toner image formation is as long as, for example, 20 minutes.

Next, prior to performing the M image forming raster exposure based on the M signal, the developing device assembly 420 is rotated counterclockwise to move the M developing roll 420M to the photosensitive drum 41.
4 Next, the leading position of the previously formed C visible image is detected by the leading end detecting means 426, and in the copy mode, a request signal REQ to "send the recording M image data after a predetermined time" is again issued to the scanner module 200. . This request signal is issued at the time when the image position detecting unit 426 detects a registration C toner mark image which is slightly ahead of the effective C image in the previous process. In addition, a method in which a permanent mark is previously attached to the intermediate transfer belt instead of the C toner mark image may be used.

If the M signal is sent in exact synchronization with the request signal, M image exposure, development, and primary transfer are performed, and accurate color plate matching with the original existing C image, that is, intermediate The M image correctly overlaps the C image on the transfer belt 415. When the M raster image is exposed in this manner, in the exposed portion of the photosensitive drum 414 that is initially uniformly charged, the charge proportional to the amount of exposure light disappears, and an electrostatic latent image is formed.

The M toner in the developing device 420M is negatively charged, and the developer on the developing roll 420M of the present developing device is in contact with the photosensitive drum 414 and is biased to the same potential as in the C development. . Therefore, the photosensitive drum 414
No toner adheres to the portion where the electric charge remains, and the M toner is attracted to the portion exposed by the M signal, so that an M visible image similar to the electrostatic latent image is formed.

Similarly, the Y image is placed on the CM toner image,
The K image is formed to be superimposed on the CMY image. Note that the basic image processing circuit 300 uses UCR (under color removal).
Since the processing is performed, there is little chance that one pixel is developed with all four colors of toner. The full-color image formed on the intermediate transfer belt 415 that has been rotated at least four times in this way is eventually transferred to the secondary transfer 417 portion by rotation.

On the other hand, when the image formation is started, the transfer paper 1
90 is fed from one of three feeding units, namely, the cassette 412A, the manual sheet feeding tray 412B or the external feeding port 412C, by the feeding or conveying action of the feeding rolls 413A, 413B or the conveying roll pair 413F, and the register roll pair. Waiting at nip of 418R. When the leading end of the toner image on the intermediate transfer belt 421 approaches the secondary transfer corotron 427, the register roll pair 418R is driven so that the leading end of the transfer paper 190 coincides with the leading end of the image, and the registration of the paper and the image is performed. Is performed.

In this way, the transfer paper is superimposed on the intermediate transfer belt image and passes under the secondary transfer corotron 417 connected to the positive potential power supply. At this time, the transfer paper is charged with a positive charge by the corona discharge current, and most of the toner image is transferred onto the transfer paper. Subsequently, when passing through a neutralization core (not shown) connected to a grounding source located slightly to the left of the secondary transfer corotron 417, the transfer paper discharges electric charges, and the attraction force between the intermediate transfer belt and the transfer paper almost disappears. . Eventually, the weight of the transfer paper exceeds the attraction force, and the transfer paper 190 is separated from the intermediate transfer belt and moves to the transport belt 422.

The transfer paper on which the toner image is placed is transported by a conveyor belt 42.
2 to the fixing device 423. At this time, heat and pressure are applied to the heated nip portion between the fixing roll 423A and the backup roll 423B, so that the toner is melted and enters the transfer paper 190 into the fibers, thereby fixing the image. That is, a copy image is completed. Thereafter, the completed copy is sent out of the main body by the discharge roll pair 424. The discharged copy paper is stacked face up on a tray (not shown).

In the case of double-sided copying, the switching roll 425 is moved to the right along with the deflection of the paper, pressed against the opposite transporting roll to once invert the transfer paper, and then is automatically transported by the transporting roll pair 412H. Lead to. At this time, the copied transfer paper 190A is stacked with the copy side up.

In FIG. 3, reference numeral 501 denotes a manual paper feeder 412;
A unit for reading the back side of the sheet fed from B. Reference numeral 502 denotes a unit for reading the back surface of the copy sheet re-fed from the reversing unit 412A. 50
Reference numeral 3 denotes a CCD reading sensor, and reference numeral 505 denotes a sheet on which a copy is already made on the front side and a copy is made on the back side. The CCD reading sensor 503 is placed in parallel with the copy paper 505 in the main scanning direction. CCD sensor 5
Reference numeral 03 denotes a self-illuminating unit, which is a contact type sensor having a light source for illuminating a document inside.

FIG. 4 shows the reading units 501 and 5 of FIG.
02 is seen from the side. In FIG. 4, reference numeral 506 denotes a blue filter for reading a specific pattern printed in yellow on the surface of copy paper. When the sheet copied as shown in FIG. 4 is fed again, the reading units 501 and 502
, A specific pattern on the copy surface can be read.

FIG. 5 shows an electric signal from the CCD sensor 503. In FIG. 5, (1) shows an output signal from the CCD reading sensor 503 placed parallel to the main scanning direction. On the surface of the copy sheet 505, a copied yellow specific pattern 505a is formed.

FIG. 6 shows the output from the CCD reading sensor 503 in the main scanning direction. (1),
Is a reference signal 1 for writing, which is a reference for main scanning writing. (2) is a reference dot signal 1, which is a reference signal for generating a specific pattern on a copy. When copying the front side, a specific pattern is printed by the reference dot signal. Next, it is assumed that when the copy paper is fed again, the CCD reading sensor 503 reads the yellow specific pattern on the copy and outputs the detection dot signal of (3). Here, in order to make the CCD output signal of FIG. 5 easy to understand, the polarity is inverted in the detection dot signal of (3).

Now, the reference dot signal 1 of (2) and (3)
If the detected dot signal has a phase difference Δt, it means that the copy sheet is shifted in the main scanning direction for some reason when the back side is fed. The cause is the accuracy of the manual feed unit or the duplex unit. (4) is a write reference signal 2, which is different from the write reference signal 1 in (1) by Δt.
Only the phase is shifted. On the reverse side, the deviation at the time of sheet feeding can be canceled by using the writing reference signal 2 of the main scanning. (5) is a reference dot signal 2 generated from the writing reference signal 2, which coincides with the detection dot signal of (3).

The main scanning has been described above, but the same applies to the sub-scanning. In FIG. 7, (1) a write reference signal is generated for each sub-scanning line. CCD
If the reading sensor 503 measures time 1 from when the edge of the copy paper is detected until the dot is detected for the first time, the image position on the front surface can be known. Also in the sub-scanning correction, by making the positions until the first dot is printed on the back surface the same, the image positions on the front and back surfaces can be aligned.

FIG. 8 is a flow chart for double-sided copying. In step S1, front side copying is performed normally. In step S2, the copy paper is reversed by a manual feed or an automatic duplex unit. Step S
At 3, the sheet is fed to the registration rollers. In step S4, the specific pattern of the surface copied at this time by the reading unit is read.

In step S5, the difference between the dot of the specific pattern and the reference dot is detected. In step S6, the write reference signal is corrected at the start timing of the main scan and the sub scan. In step S7, an image is written on the photoconductor at the corrected timing. Step S
At 8, the image written on the photoreceptor is transferred to the back side of the copy paper and fixed. In step S9, the duplex copy is discharged onto a tray.

FIG. 9 is a flow chart in the case where the sub-scanning is corrected by the start signal of the registration roller. In step S11, it is possible to align the registration of the front and back images in the case of both sides of the manual feed. Step S
In 12, the manual sheet feeder has a function of reading a specific pattern added to the copy surface, so that the registration of the front and back images when both sides are manually inserted can be aligned.

In step S13, the registration of the front and back images can be aligned in the case of automatic double-sided printing. In step S14, the main body paper feed unit has a function of reading the specific pattern added to the copy surface, so that the registration of the front and back images during automatic double-sided printing can be made uniform.

In step S15, the registration adjustment in the main scanning and the registration adjustment in the sub-scanning direction can be corrected by changing the registration timing of writing. In step S16, the registration adjustment in the sub-scanning direction can be corrected by changing the sheet feeding timing.

[0052]

As is apparent from the above description, the image processing apparatus according to the first aspect of the present invention adds a specific pattern to a copy image, transfers it to copy paper, reads a specific pattern, and reads this specific pattern. The registration error of the copy image is calculated from the specific pattern and corrected. Therefore, the resist can be aligned and the image quality can be improved.

Further, in the image processing apparatus according to the second aspect of the present invention, the function of reading a specific pattern added to the copy surface is provided in the manual paper feed unit, so that the registration of the front and back images at the time of manual both sides is aligned. be able to.

According to a third aspect of the present invention, a specific pattern is added to a copy image, transferred to copy paper, a specific pattern is read, and a registration shift of the copy image is calculated from the read specific pattern. Then, the position of the image formed on the back surface of the copy sheet is corrected based on the calculation result. Therefore, in double-sided copying, the resists on the front and back can be aligned, and even in a color original, the resists can be aligned and the white spots can be prevented from shifting.

According to the image processing apparatus of the present invention, the registration adjustment in the main scanning direction and the registration adjustment in the sub-scanning direction can be corrected by changing the writing registration timing.

In the image processing apparatus according to the fifth aspect of the invention, the registration adjustment in the sub-scanning direction can be corrected by changing the timing of sheet feeding.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram in which an embodiment of an image processing apparatus of the present invention is applied to a digital full-color copying machine.

FIG. 2 is a partial view of the image processing unit of FIG. 1;

FIG. 3 is a plan view showing a configuration of a unit for reading the back surface of a sheet.

FIG. 4 is a side view illustrating a configuration of a unit for reading the back surface of a sheet.

FIG. 5 is a diagram showing a relationship between a specific pattern on a copy and a detection signal of a CCD sensor.

FIG. 6 is a diagram illustrating an output from a CCD reading sensor in a main scanning direction.

FIG. 7 is a diagram illustrating an output from a CCD reading sensor in a sub-scanning direction.

FIG. 8 is a flowchart illustrating an operation example when performing duplex copying.

FIG. 9 is a flowchart illustrating an operation example of correcting sub-scanning by a start signal of a registration roller.

[Explanation of symbols]

 180 Original image 200 Scanner module 201 DC power supply 202 Platen glass 202B Individual identification barcode plate 203 Document illumination lamp 205 Imaging lens 207 Color imaging device 208 First carriage 209 Second carriage 211 Carriage home sensor 230 First communication control means 250 Image reading means 300 Basic image processing means 350 Extended image processing means 400 Printer module 401 Power supply means 414 Photoconductor drum 415 Intermediate transfer member 419 Charging means 420 Developing means 427 Second transfer means 430 Second communication control means 441 Laser exposure means 500 Image Forming unit 501 Unit for reading the back side of paper 502 Unit for reading the back side of copy paper 503 For CCD reading sensor 505 (to copy on the back side)

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI H04N 1/387

Claims (6)

[Claims] A function unit for adding a specific pattern to a copy image and transferring the copy pattern onto a copy sheet; a function unit for reading the specific pattern; and calculating a registration shift of the copy image from the read specific pattern. An image processing apparatus, comprising: a function unit for performing correction. 2. The image processing apparatus according to claim 1, wherein the function unit for reading the specific pattern is provided in a manual sheet feeding unit. 3. A function unit for adding a specific pattern to a copy image and transferring it to copy paper, a reversing unit for reversing the discharged copy paper upside down and feeding the same again, and a function unit for reading the specific pattern And an operation unit for calculating a registration shift of a copy image from the read specific pattern, and a function unit for correcting an image position to be formed on the back surface of the copy sheet based on the operation result. Processing equipment. 4. The image processing apparatus according to claim 3, wherein the function section for reading the specific pattern is provided in a main body sheet feeding section. 5. The image processing apparatus according to claim 3, wherein the function unit for correcting the image position performs registration adjustment in the main scanning direction and the sub-scanning direction by adjusting writing timing. . 6. The image processing apparatus according to claim 3, wherein the function section for correcting the image position performs registration adjustment in the sub-scanning direction by adjusting paper feed timing.