JP2003131468A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus by which the repeated deviation in the main scanning of a quick component that exists on the same page can be removed. SOLUTION: A repeated waveform pattern is separated and extracted from a chart for analyzing color slurring and stored in a storage means. In the case of starting printing, a pattern recognition part compares the character of the repeated waveform pattern stored in the storage means with the value of the deviation in a main scanning direction detected by a sensor and detects the phase information of each repeated waveform pattern. When a correction data generation part predicts the repeated waveform pattern stored in the storage means and the main scanning deviation component of every color according to the detected phase information, an image output control circuit adjusts the write-in timing of an image output means based on the predicted main scanning deviation information so as to perform a printing job. Thus, printing is performed while cancelling the repeated component of positional deviation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is capable of electrostatically transferring an image to which data has been transferred by optical writing onto a photoconductor in a plurality of image forming units in which a plurality of image forming units are arranged along a conveyor belt. The present invention relates to an image forming apparatus such as a printer or a digital copying machine.

[0002]

2. Description of the Related Art Conventionally, a latent image forming means having a plurality of photoconductors and forming latent images of different color information on the surface of each photoconductor, and a visualizing means for visualizing the latent image. 2. Description of the Related Art An image forming apparatus, which is composed of a transfer unit configured to transfer a visible image on each photoconductor to a transfer sheet conveyed on a transfer belt and is capable of forming a color image, is used. As such an image forming apparatus, there is, for example, a tandem type color image forming apparatus in which a plurality of image forming units are arranged along a conveyor belt (see FIG. 1). In the tandem type color image forming apparatus, images of respective colors are formed by different image forming means, and the formed images are superposed on the transfer belt to form one color image.
Color shift due to various factors may occur. Examples of this color shift component include a shift in the main scanning direction, a shift in the sub-scanning direction, a shift in magnification in the main scanning direction, and a shift in angle in the main scanning direction.

Therefore, as a method of preventing color misregistration, a predetermined image position recognition pattern is formed on the transfer belt, the misregistration amount is obtained from the detected value, and the color misregistration is corrected by correcting the writing timing or the like. Methods to reduce it have been proposed. In the usual case, a registration cycle is provided separately from the normal job cycle, and a method for surely detecting the deviation amount is provided by providing an image position recognition pattern of a certain size and its pitch. . Japanese Patent Laid-Open No. 6-253151 discloses a method of detecting the amount of deviation during image formation as described above. By performing rough adjustment and fine adjustment of sample timing, a multi-valued image forming apparatus capable of performing accurate correction. Registration registration image sampling method is described. In addition, JP-A-8
No. 6347 discloses an image sampling and color misregistration correction method of a multi-valued image forming apparatus capable of correcting registration deviation even during a print job by forming an image position recognition pattern outside the maximum paper area. Have been described.

[0004]

However, in the image sampling method described in Japanese Patent Laid-Open No. 6-253151, correction is effective only for a constant deviation peculiar to the image forming apparatus or a very slow fluctuation component. Therefore, it was not possible to correct the image position deviation of a fast component that is present in the job. Further, in the image sampling and color misregistration correction method described in JP-A-8-6347, due to restrictions such as the cleaning performance of the conveyor belt,
It is difficult to continue to form a pattern continuously, and it is difficult to correct the resist deviation component with a long period due to temperature change or the like, that is, to correct the deviation of a fast component that exists in the same page. It was SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of removing the main component repetitive shift in the fast scan which is present in the same page.

[0005]

According to a first aspect of the present invention, there is provided a photosensitive drum for each color of Y (yellow) M (magenta) C (cyan) K (black).
In an image forming apparatus having a plurality of image forming units for transferring an electrostatic latent image formed on a photoconductor drum of each K color onto a sheet to form an image, a plurality of types of registration shifts for each received YMCK color are repeated. A storage unit that stores a waveform pattern and a registration deviation amount in the main scanning direction for each of the YMCK colors are detected, and the detected registration deviation amount and the registration deviation repeated waveform pattern stored in the storage unit are compared, Based on the detection means for detecting the phase information of a plurality of types of registration deviation repeated waveform patterns for each of the YMCK colors, and the phase information detected by the detection means and the registration deviation repeated waveform patterns stored in the storage means. And the YM
Calculating means for calculating the resist deviation amount for each color of CK;
The above object is achieved by including a correction unit that performs registration correction when the image forming units of the respective colors of YMCK perform image formation based on the registration shift amount calculated by the calculation unit.

According to a second aspect of the invention, the image forming is performed by forming the image by forming a photosensitive drum for each color of YMCK and transferring the electrostatic latent image formed on the photosensitive drum of each color of YMCK onto a sheet. In an image forming apparatus having a plurality of units, a storage unit for storing a plurality of types of received resist deviation repeating waveform patterns for each of the YMCK colors and a resist deviation amount in the main scanning direction for each of the YMCK colors are detected, and the detected resist is detected. A detection unit that compares the amount of deviation with the registration deviation repeated waveform pattern stored in the storage unit to detect phase information and amplitude of a plurality of types of registration deviation repeated waveform patterns for each color of YMCK, and the detection unit. Repetition of registration deviations stored in the storage means and phase information and amplitudes detected by Based on the shape pattern, the YMC
Calculation means for calculating the registration deviation amount for each of the K colors; and correction means for performing registration correction when the image forming units of the YMCK colors respectively perform image formation based on the registration deviation amount calculated by the calculation means. The above-mentioned object is achieved by including the.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the registration shift repetitive waveform pattern stored in the storage means is the YMCK.
The above-mentioned object is achieved by using a pattern common to all colors. According to a fourth aspect of the invention, in the second aspect of the invention, the calculating means further includes setting means for setting a minimum value of the amplitude used when calculating the registration deviation amount, and the calculating means includes the detection means. When the amplitude detected by the means is equal to or smaller than the minimum value set by the setting means, the detected amplitude is not used in calculating the registration deviation amount, thereby achieving the above object.

According to a fifth aspect of the present invention, image forming is performed by forming a photosensitive drum for each color of YMCK and transferring an electrostatic latent image formed on the photosensitive drum of each color of YMCK onto a sheet to form an image. In an image forming apparatus having a plurality of parts, in the initial state of the image forming apparatus, the YMC
Detecting the amount of registration deviation in the main scanning direction for each K color,
Extraction means for extracting a plurality of types of registration deviation repeated waveform patterns for each of the YMCK colors from the detected registration deviation amount, and a plurality of types of registration deviation repeated waveform patterns for each of the YMCK colors extracted by the extraction means are stored. A registration deviation amount in the main scanning direction for each of the YMCK colors is detected, and the registration deviation repeating waveform pattern stored in the storage means is compared, and a plurality of types of registration deviation repeating waveform patterns for each of the YMCK colors are stored. Of the YM based on the phase information and the amplitude detected by the detecting means, and the registration deviation repeating waveform pattern stored in the storage means.
Calculating means for calculating the resist deviation amount for each color of CK;
The above object is achieved by including a correction unit that performs registration correction when the image forming units of the respective colors of YMCK perform image formation based on the registration shift amount calculated by the calculation unit.

According to a sixth aspect of the invention, in the fifth aspect of the invention, the extracting means detects the registration shift amount in the main scanning direction for each color of the YMCK even when the image forming apparatus is not in the initial state. A plurality of types of repetitive registration deviation waveform patterns for each color of the YMCK are extracted from the detected registration deviation amount, and the storage means
The above-mentioned object is achieved by updating and storing the resist shift repeating waveform pattern newly extracted by the extracting means.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS.
FIG. 1 is a diagram showing a schematic configuration of the image forming apparatus according to the present embodiment. In the present embodiment, as an example of the image forming apparatus, as shown in FIG. 1, a color image forming apparatus called a tandem type in which a plurality of image forming units are arranged along a conveyor belt will be described. The color image forming apparatus according to the present embodiment is provided with a plurality of image forming units, each image forming unit has a plurality of photoconductors, and the latent image of different color information is provided on the surface of each photoconductor. A latent image forming unit that forms an image and a unit that visualizes the latent image are provided, and a color image can be obtained by transferring the developed image on each photoconductor to a transfer paper conveyed on a transfer belt. It is like this. Specifically, as shown in FIG. 1, in the color image forming apparatus, the transfer belt 102 that transfers the transfer sheet 101 and the transfer roller 10 are used.
3, 104, a paper feed tray 105, an exposure device 108, a fixing device 113, and a plurality of image forming units.

In the present embodiment, a plurality of image forming units provided in the color image forming apparatus have different Ys.
The first, second, third, and fourth image forming units that form images of respective colors (yellow), M (magenta), C (cyan), and K (black) will be described. The first image forming unit is an image forming unit that forms a yellow image, and includes a photoconductor drum 106Y, a charger 107Y arranged around the photoconductor drum 106Y, a developing unit 109Y, a photoconductor cleaner 110Y, and a transfer unit. Equipped with Y. Similarly, the second
The image forming unit is an image forming unit that forms a magenta image, and includes the photosensitive drum 106M and the photosensitive drum 106M.
A charger 107M and a developing device 109M arranged around the
The photoconductor cleaner 110M and the transfer device M are provided.
The third image forming unit is an image forming unit that forms a cyan image, and includes a photoconductor drum 106C, a charger 107C arranged around the photoconductor drum 106C, and a developing device 1.
09C, a photoconductor cleaner 110C, and a transfer device C. Further, the fourth image forming unit is an image forming unit that forms a black image, and includes the photoconductor drum 106K,
Charging device 107 arranged around the photoconductor drum 106K
K, a developing device 109K, a photoconductor cleaner 110K, and a transfer device K.

The operation of forming a color image in each image forming section of the color image forming apparatus will be described with reference to FIG. First, second, third, and fourth image forming units that form images of different colors Y, M, C, and K are arranged in a line along a conveyor belt 102 that conveys the transfer paper 101. The conveyor belt 102 is stretched around a drive roller, one of which is driven to rotate, and the other of the conveyor rollers 103 and 104, which are driven rollers that are driven to rotate. The conveyor belt 102 is rotationally driven in the arrow direction by the rotation of the conveyor rollers 103 and 104. . A paper feed tray 105 that stores transfer paper is provided below the conveyor belt 102. The transfer paper 101 that is at the uppermost position of the transfer paper stored in the paper feed tray 105 is fed at the time of image formation. Then, it is adsorbed on the conveyor belt 102 by electrostatic adsorption. The attracted transfer paper 101 is conveyed to the first image forming unit, where the yellow image is formed.

Photoreceptor drum 106Y of the first image forming section
After being uniformly charged by the charging device 107Y, the surface of the laser light 11 from the exposure device 108 corresponds to the yellow image.
1Y is exposed and an electrostatic latent image is formed. The formed electrostatic latent image is developed by the developing device 109Y, and the photosensitive drum 1
A toner image is formed on 06Y. This toner image is transferred onto the photosensitive drum 106Y and the transfer paper 101 on the conveyor belt 102.
The image is transferred onto the transfer paper 101 by the transfer device 112Y at a position (transfer position) in contact with the transfer paper 101, and a single color (yellow) image is formed on the transfer paper 101. After the transfer, the photoconductor drum 106Y is cleaned of unnecessary toner remaining on the surface of the photoconductor drum 106Y by the photoconductor cleaner 110Y to prepare for the next image formation. In this way, a single color (yellow) is generated in the first image forming unit (yellow).
The transfer paper 101 on which is transferred is transported to the second image forming unit (magenta) by the transport belt 102.

Similarly, in the second image forming unit, the surface of the photosensitive drum 106M is uniformly charged by the charger 107M, and then exposed by the laser beam 111M corresponding to the magenta image from the exposure unit 108. , An electrostatic latent image is formed. The formed electrostatic latent image is developed by the developing device 109M, and a toner image is formed on the photosensitive drum 106M. This toner image is transferred at the transfer position by the transfer device 112Y so as to be superimposed on the single-color (yellow) image formed on the transfer paper 101 by the first image forming unit. After the transfer, the photoconductor drum 106M is cleaned of unnecessary toner remaining on the surface of the photoconductor drum 106M by the photoconductor cleaner 110M to prepare for the next image formation. Then, the transfer paper 101 is conveyed to the third image forming unit (cyan). Similarly, in the third image forming unit, the surface of the photoconductor drum 106C is uniformly charged by the charger 107C, and then exposed by the laser beam 111C corresponding to the magenta image from the exposure unit 108, and electrostatically charged. A latent image is formed. The formed electrostatic latent image is developed by the developing device 109C, and a toner image is formed on the photoconductor drum 106C. This toner image is transferred to the transfer paper 1 by the transfer device 112C at the transfer position.
01 is superimposed and transferred onto the images formed by the first image forming unit and the second image forming unit. After the transfer, the photoconductor drum 106C is cleaned of unnecessary toner remaining on the surface of the photoconductor drum 106C by the photoconductor cleaner 110C to prepare for the next image formation. Further, the transfer paper 101 is the fourth image forming unit (black).
Be transported to.

Similarly, in the fourth image forming section, the surface of the photosensitive drum 106K is uniformly charged by the charger 107K, and then exposed by the laser beam 111K corresponding to the magenta image from the exposure device 108. , An electrostatic latent image is formed. The formed electrostatic latent image is developed by the developing device 109K, and a toner image is formed on the photoconductor drum 106K. This toner image is transferred at the transfer position by the transfer device 112K so as to be superimposed on the images formed on the transfer paper 101 by the first, second and third image forming portions. After the transfer, the photoconductor drum 106K is cleaned of unnecessary toner remaining on the surface of the photoconductor drum 106K by the photoconductor cleaner 110K to prepare for the next image formation. After the toner image formed by the fourth image forming unit is transferred, all the Y, M, C, and K image formation is completed, and the color image is formed on the transfer paper 101. Then, the transfer paper 101 on which the color image is formed is separated from the conveyor belt 102 after passing through the fourth image forming unit, fixed by the fixing device 113, and ejected.

Next, the registration deviation correction at the time of image formation in the color image forming apparatus according to this embodiment will be described. FIG. 2 is a block diagram showing a configuration relating to registration correction of the image forming apparatus. FIG. 3 is a diagram showing an example of a pattern for detecting the registration shift amount in the main scanning direction. The color image forming apparatus according to the present embodiment has a pattern generation unit 201, storage units 202Y, 202M, 202C, and 2 as a configuration for executing registration correction.
02K, pattern recognition units 203Y, 203M, 203
C, 203K, Y correction data generation unit 204Y, M correction data generation unit 204M, C correction data generation unit 204C, K
Correction data generation unit 204K, image output control circuit 205,
The sensor unit 206 and the image output unit 207 are provided.

Each storage means 202Y, 202M, 202
C and 202K are means for storing a plurality of repetitive waveform patterns for each color (Y, M, C, K), and in FIG. 2, as an example, there are two types of repetitive waveform patterns for each color. Is shown. Thus, in the present embodiment, the storage unit 202Y has a storage unit 2021Y that stores the repetitive waveform pattern Y1 and a storage unit 2022Y that stores the repetitive waveform pattern Y2. Similarly,
The storage unit 202M stores a storage unit 2021M that stores the repetitive waveform pattern M1, a storage unit 2022M that stores the repetitive waveform pattern M2, and a storage unit 202C that stores the repetitive waveform pattern C1 and a storage unit 2022C that stores the repetitive waveform pattern C2. The storage means 202K has a storage means 2021K for storing the repetitive waveform pattern K1 and a 2022K for storing the repetitive waveform pattern K2. Also, the pattern recognition unit 20
3Y includes a pattern Y1 recognition unit 2031Y and a pattern Y2.
It has a recognition unit 2032Y. Similarly, the pattern recognition unit 203M includes the pattern M1 recognition unit 2031M, the pattern M2 recognition unit 2032M, and the pattern recognition unit 203C.
Is a pattern C1 recognition unit 2031C and a pattern C2 recognition unit 2032C, and a pattern recognition unit 203K is a pattern K1 recognition unit 2031K and a pattern K2 recognition unit 2032K.
have.

The pattern generator 201 generates a pattern for detecting the amount of deviation in the main scanning direction. The sensor unit 206 is a sensor that detects the amount of deviation in the main scanning direction during image formation. The image output control circuit 205 adjusts the timing of the pattern generated by the pattern generation unit 201 and controls the output of the image output unit 207. The pattern generated to detect the amount of deviation in the main scanning direction may be, for example, the one shown in FIG. Y as shown in FIG.
It may be a repeating pattern of M, C and K, or as shown in FIG.
Y, M, C, K with some spacing as shown in
It may be a straight line. In addition, in FIG. 3, C is used as a sensor.
Using a CD (photoelectric conversion element), the conveyor belt 102 of FIG.
Although the case where a pattern is formed is shown above, the present invention is not limited to this, and it is sufficient if the configuration is such that different patterns and different sensors are used and the amount of deviation in the main scanning direction can be detected. To do.

Here, the repetitive waveform pattern according to the first embodiment will be described. FIG. 4 is a diagram showing a system for decomposing / analyzing a waveform. FIG. 5 is a diagram showing an example of a repetitive waveform pattern. In this embodiment, the analysis sample image once output by the color image forming apparatus is decomposed / analyzed by the system as shown in FIG. With this system, the analysis sample image can be acquired as a repetitive waveform pattern as shown in FIG. The system shown in FIG. 4 includes a high-precision scanner 42 and a computer 43 that read an analysis sample image 41. A predetermined image output by the color image forming apparatus is read as a sample image 41 for analysis by a high-precision scanner 42, and the read data is analyzed by a computer 43.
It can be decomposed into a repetitive waveform pattern as shown in FIG. The waveform decomposition algorithm may be any method such as frequency decomposition or human judgment. By decomposing the data read by the high-precision scanner 42 in this manner, a high-speed repetitive waveform pattern can be acquired.

Now, the repetitive waveform pattern of FIG. 5 will be described. For example, a case where the analysis sample image 41 is acquired by the computer 43 as a repetitive waveform pattern having a positional deviation as shown in FIG. When the repetitive waveform pattern of FIG. 5A is largely decomposed by the computer 43, FIG.
Further, the components shown in FIG. 5C can be used. Note that the periodic repetitive waveform pattern at the time of image formation in the image forming apparatus is a rotating portion of the main body mechanism (for example,
Since it depends on the photosensitive drum), each cycle is stable, but the phase between each repeating waveform is often random. Also, there are variations among individual machines.

In this embodiment, the repetitive waveform pattern of the image forming apparatus acquired in advance is stored in the storage means 202 of FIG.
It is stored in Y, 202M, 202C and 202K. The pattern recognition units 203Y, 203M, 203C, 203K
This storage means 202Y, 202M, 202C, 202K
The phase of each repetitive waveform pattern is detected by comparing the characteristic of the repetitive waveform pattern stored in 1) with the value of the shift amount in the main scanning direction detected by the sensor unit 206. The Y, M, C, and K correction data generation units 204Y, 204M, 204C, and 204K have the repetitive waveform patterns stored in the storage units 202Y, 202M, 202C, and 202K, and for each color according to the phase information. Predict the main scanning deviation component. Image output control circuit 2
In the image forming apparatus according to the present embodiment, the repetitive component relating to the positional deviation at the time of image formation can be canceled by adjusting the write timing of the image output unit 207 based on the predicted main scanning deviation information 05. It has become.

The above operation will be described with reference to FIG. FIG. 6 is a flowchart showing the processing procedure of the operation of the image forming apparatus according to the first embodiment. Note that FIG.
(A) is a flowchart showing a processing procedure for detecting a repetitive waveform pattern peculiar to the image forming apparatus, which is processing performed in the initial state. Also, FIG. 6 (b)
FIG. 6 is a flowchart showing a processing procedure for correcting the positional deviation using the detected repetitive waveform pattern. First, in the system as shown in FIG. 4, when a color shift analysis chart is output (step 601), repetitive waveform patterns are separated / extracted from this analysis chart (step 602). Then, the extracted repetitive waveform pattern is input to the storage unit of the image forming apparatus and stored (step 603).

In the image forming apparatus, when the printing is started (step 611), the pattern recognition unit determines the characteristics of the repetitive waveform pattern stored in the storage unit and the value of the deviation amount in the main scanning direction detected by the sensor. By comparing, the phase of each repetitive waveform pattern is detected (step 612). The phase information of all the repetitive waveform patterns is detected (step 613; Y), the correction data generating unit stores the repetitive waveform pattern in the storage means, and the main scanning deviation component for each color according to the detected phase information. , The image output control circuit subsequently adjusts the write timing of the image output means based on the predicted main scanning shift information, and the print job is executed (step 6).
14) and the printing ends (step 615). As a result, printing can be executed while canceling the repetitive component of misalignment.

Next, a second embodiment will be described with reference to FIGS. 5, 7, 8 and 9. FIG. 7 shows the second
It is a figure showing the pattern recognition part of the embodiment of. Figure 8
3 is a flowchart showing a processing procedure for separating a repetitive waveform pattern. FIG. 9 is a diagram showing an example of a repetitive waveform pattern and a waveform detected / generated according to a state change in the horizontal axis direction. The pattern recognition unit of the second embodiment shown in FIG. 7 is a configuration in which the pattern recognition unit of FIG. 2 is further detailed, and the inclination of each of the two repetitive waveform patterns stored in the above-mentioned storage means. Is detected, and the amplitude and phase are also detected according to the detected inclination to generate a new waveform. Here, as an example, the storage unit 202Y in FIG.
The pattern recognition unit 203Y will be described, but the storage units 202M, 202C, 202K and the pattern recognition unit 2 will be described.
The 03M, 203C, and 203K have the same configuration. Further, in the present embodiment, the repetitive waveform pattern stored in the storage unit 2021Y is the repetitive waveform pattern Y1 shown in FIG.
It is assumed that FIG.

The above-mentioned repetitive waveform pattern has a stable cycle, but the amplitude may vary. Therefore,
For example, a repetitive waveform pattern in which a positional shift in the main scanning direction may occur as shown in FIG. 9A will be described. In the case of the repetitive waveform pattern as shown in FIG. 9A, the inclination of the detected waveform is monitored and the point 901 in FIG. 9A at which the inclination sharply changes from positive to negative is detected. Based on the amplitude and phase at this time, a waveform obtained by raising the amplitude in FIG. 5C is generated as the waveform Y11. Since the waveform Y11 is determined after the detection, the waveform becomes as shown in FIG. 9B. When this waveform Y11 is subtracted from the detected waveform, FIG.
The waveform is as shown in (c). The slope of this waveform is obtained, the point 902 at which the slope changes from positive to negative is detected, and the waveform Y12 is generated from the amplitude at this time.

The above operation will be described with reference to FIG. The component of the waveform Y11 is detected from the inclination of the original waveform (step 801). Generate a component signal of waveform Y11 (step 8
02), a signal is generated by subtracting the component of the waveform Y11 from the original waveform (step 803). The component of the waveform Y12 is detected from the slope of the waveform after the subtraction (step 804), and the waveform Y12 is detected.
Twelve component signals are generated (step 805). In addition,
Although the Y color has been described as an example in the present embodiment as described above, the waveforms M11, M12, C11, C12, K11, and M11, M12, C12, K11, K11
It shall be possible to generate K12. Further, each waveform Y11, Y12, M11, M12, C11, C12,
After the generation of K11 and K12, the Y, M, C, and K correction data generation units 204Y, 204M, 204C, and 204K, the image output control circuit 205, and the image output unit 207 process,
Since it is the same as the case of the correction according to the first embodiment, the description thereof will be omitted.

Next, a third embodiment will be described with reference to FIG. FIG. 10 is a block diagram showing a configuration relating to registration correction of the image forming apparatus according to the third embodiment. It should be noted that FIG. 10 has a configuration in which the repeated waveform patterns among the colors Y, M, C, and K are the same, and the description of the same components as those in FIG. 2 will be appropriately omitted. When the repeated waveform patterns among the colors Y, M, C, and K are the same, the configuration corresponds to each color in FIG. 2, but in FIG. 10, the storage unit 2020 is used commonly for all colors. . Other pattern recognition unit 203
Y, 203M, 203C, 203K, Y, M, C, K
Correction data generation unit 204Y, 204M, 204C, 20
The operation of 4K or the like is similar to that in the case of the correction according to the first embodiment, and by adjusting the write timing or the like, the repetitive component relating to the positional deviation during image formation can be canceled.

Next, a fourth embodiment will be described with reference to FIG. The fourth embodiment further includes a setting unit that allows the user to arbitrarily set whether or not to use the waveform detected / generated from the repetitive waveform pattern for registration deviation correction, from the operation unit of the image forming apparatus. It is an embodiment. FIG. 11 is a diagram showing the configuration of the pattern recognition unit of the fourth embodiment. It should be noted that here, as in the case of FIG. 7, an example will be described using the storage unit 202Y and the pattern recognition unit 203Y in FIG.
02M, 202C, 202K and pattern recognition unit 20
It is assumed that 3M, 203C, and 203K have the same configuration.

When the user recognizes the waveform Y11 and the waveform Y12 by the setting means of the operation unit (not shown), if the recognized waveform Y11 is equal to or smaller than the minimum amplitude setting value, the waveform Y11 is at a level without any problem. It can be set so that it is recognized that there is a waveform and the waveform as shown in FIG. 9B is not generated. In this case, the pattern recognition unit of FIG. 11 compares the condition of the minimum amplitude setting value set by the user in this setting means with the recognized waveform Y11 to determine whether or not the repetitive waveform pattern has a problem level. to decide. Similarly, for the waveform Y12, when the user sets the minimum amplitude setting value by the setting means, the condition of the minimum amplitude setting value set by the user is compared with the recognized waveform Y12, whereby a repetitive waveform pattern is obtained. Judge whether the level is acceptable. In the present embodiment, the repetitive waveform patterns that are determined to have no problem are assigned to the Y, M, C, and K correction data generation units 204Y, 204M, 204C, and 204K.
It is not used for predicting the main scanning shift component for each color. With such a configuration, it is possible to provide a circuit that prevents a malfunction with respect to a non-repeating noise component.

Next, a fifth embodiment will be described.
The fifth embodiment is an embodiment in which the repetitive waveform pattern that has been decomposed / analyzed by the external system in the first embodiment is separated / extracted by the repetitive waveform pattern extraction unit provided inside the image forming apparatus. FIG. 12 is a block diagram showing a configuration relating to registration correction of the image forming apparatus according to the fifth embodiment. Further, FIG. 13 is a flowchart showing a processing procedure of the operation of the image forming apparatus according to the fifth embodiment. As shown in FIG. 12, the image forming apparatus of the fifth embodiment is similar to the first embodiment in that the repeated waveform pattern extraction units 208Y, 208M,
The configuration further includes 208C and 208K. Repetitive waveform pattern extraction units 208Y, 208M,
208C and 208K separate and extract repetitive waveform patterns when the image forming apparatus is powered on and is in an initial state, for example. When each repetitive waveform pattern is a component that can be approximated to a sine wave, the repetitive pattern extraction units 208Y, 208M, 208C, 208K
Is an FFT (Fast Fourier Transform)
orm; fast Fourier transform)
Can be separated.

The operation of the image forming apparatus of the fifth embodiment will be described here. FIG. 13A is a flowchart showing a processing procedure for separating / extracting a repetitive waveform in the initial state. First, a detection pattern of the main scanning shift amount is generated (step 1301), and after this detection pattern is formed, the repetitive waveform pattern extraction units 208Y and 208Y are formed.
Repeated waveform patterns are separated and extracted by FFT or the like at M, 208C, and 208K (step 130).
2). Then, the separated / extracted repetitive waveform pattern is input to and stored in the storage means of the image forming apparatus (step 1303). Further, FIG. 13B is a flowchart showing a processing procedure for performing positional deviation correction and printing using the detected repetitive waveform pattern. In the image forming apparatus, when printing is started (step 1311),
A main scanning shift amount detection pattern is generated (step 131).
2) The pattern recognition section detects the phase information of all repetitive waveform patterns (step 1313). When the phase information of all repetitive waveform patterns is detected (step 1313; Y), the repetitive waveform pattern stored in the storage unit by the correction data generation unit and the main scanning deviation component for each color according to the detected phase information. , The image output control circuit subsequently adjusts the write timing of the image output means and the like based on the predicted main scanning shift information, and the print job is executed (step 131).
4) Then, the printing ends (step 1315). As a result, printing can be executed while canceling the repetitive component of misalignment.

Next, referring to FIG. 12 and FIG.
Will be described. The sixth embodiment is shown in FIG.
The fifth embodiment shown in FIG. 2 is similar to the fifth embodiment in the configuration after the storage means, but is different in that an operation and repetitive waveform pattern extraction unit is provided. In the sixth embodiment, the repetitive waveform pattern extraction units 208Y, 208M, 208C, and 2 are used even in cases other than the initial state of the image forming apparatus.
08K separates and extracts repetitive waveform patterns,
It is an embodiment of storing in a storage means. Similar to the fifth embodiment, the repetitive waveform pattern extraction units 208Y, 208
M, 208C, and 208K have a function of separating and extracting repetitive waveforms. For example, when each repetitive waveform pattern is a component that can be approximated to a sine wave, the repetitive waveform pattern extraction units 208Y, 208M, and 208.
The C and 208K are capable of separating / extracting repetitive waveform patterns by applying FFT or the like.

FIG. 14 is a flowchart showing the processing procedure of the operation of the image forming apparatus according to the sixth embodiment.
When printing is started (step 1401) and it is determined that the repeated waveform pattern needs to be separated / extracted (step 1402; Y), after the detection pattern of the main scanning misalignment amount is generated (step 1402; Y), the same as in the fifth embodiment. Step 140
3) The repetitive waveform pattern extraction unit performs the repetitive waveform pattern separation / extraction operation (step 140).
4). Then, the separated / extracted repetitive waveform pattern is stored in the storage means (step 1405). When it is determined that it is not necessary to separate / extract the repetitive waveform pattern (step 1402; N), or after the repetitive waveform pattern is stored in the storage unit (step 1405), the main scanning shift amount detection pattern is generated (step 1406),
The pattern recognition section detects the phase information of all repetitive waveform patterns (step 1407). After detecting the phase information of all repetitive waveform patterns (step 14
07; Y), the correction data generation unit predicts the main scanning deviation component for each color according to the repetitive waveform pattern stored in the storage unit and the detected phase information, and then the image output control circuit is predicted. Based on the main scanning deviation information
The print job is executed by adjusting the writing timing of the image output unit (step 1408), and the printing ends (step 1409). As a result, printing can be executed while canceling the repetitive component of misalignment.

[0034]

According to the first aspect of the invention, based on each phase information detected by the detection means and each registration deviation repetitive waveform pattern stored in the storage means,
A calculation unit that calculates the registration deviation amount for each color of YMCK, and a correction unit that performs registration correction when the image forming units of each color of YMCK perform image formation based on the registration deviation amount calculated by the calculation unit. Since it is provided, it is possible to remove the main scanning repetitive shift of a fast component that exists in the same page.

According to the second aspect of the present invention, the registration deviation amount for each color of YMCK is calculated based on each phase information and each amplitude detected by the detection means and each registration deviation repeated waveform pattern stored in the storage means. And a correction unit that performs registration correction when the image forming units of the respective colors of YMCK perform image formation based on the registration deviation amount calculated by the calculation unit. It can be carried out.

According to the third aspect of the present invention, the registration shift repeated waveform pattern stored in the storage means is YMCK.
Since the pattern is common to all colors, it is possible to cancel the main scanning repetitive shift while reducing the circuit scale.

When the amplitude detected by the detecting means is less than or equal to the minimum value set by the setting means, the calculating means is used when calculating the detected deviation amount. Therefore, the productivity of the image forming apparatus can be improved.

According to a fifth aspect of the present invention, in the initial state of the image forming apparatus, the registration deviation amount in the main scanning direction for each YMCK color is detected, and a plurality of types of registration deviation repetition waveforms for each YMCK color are detected from the detected registration deviation amount. Since the extraction means for extracting the pattern is provided, it is possible to remove the main component repetitive shift in the fast scan which exists in the same page without using an external high precision scanner or the like.

According to the sixth aspect of the invention, the extraction means detects the registration deviation amount in the main scanning direction for each color of YMCK even when the image forming apparatus is not in the initial state, and for each color of YMCK from the detected registration deviation amount. Since a plurality of types of registration deviation repeated waveform patterns are extracted and the storage means updates and stores the registration deviation repeated waveform pattern newly extracted by the extraction means, image formation in which the components of the repetition waveform change over time Also in the device,
It is possible to remove a main component repetitive shift in the main scanning which is present in the same page.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an image forming apparatus according to an exemplary embodiment.

FIG. 2 is a block diagram showing a configuration related to registration correction of the image forming apparatus.

FIG. 3 is a diagram showing an example of a pattern for detecting a resist deviation amount in the main scanning direction.

FIG. 4 is a diagram showing a system for decomposing / analyzing a waveform.

FIG. 5 is a diagram showing an example of a repetitive waveform pattern.

FIG. 6 is a flowchart showing a processing procedure of an operation of the image forming apparatus according to the first embodiment.

FIG. 7 is a diagram showing a pattern recognition unit according to a second embodiment.

FIG. 8 is a flowchart showing a processing procedure for separating repetitive waveform patterns.

FIG. 9 is a diagram showing an example of a repetitive waveform pattern and a waveform detected / generated according to a state change in the horizontal axis direction.

FIG. 10 is a block diagram showing a configuration related to registration correction of an image forming apparatus according to a third embodiment.

FIG. 11 is a diagram showing a configuration of a pattern recognition unit according to a fourth embodiment.

FIG. 12 is a block diagram showing a configuration relating to registration correction of an image forming apparatus according to a fifth embodiment.

FIG. 13 is a flowchart showing a processing procedure of operations of the image forming apparatus according to the fifth embodiment.

FIG. 14 is a flowchart showing a processing procedure of operations of the image forming apparatus according to the sixth embodiment.

[Explanation of symbols]

201 pattern generation unit 202Y, 202M, 202C, 202K storage unit 203Y, 203M, 203C, 203K pattern recognition unit 204Y Y correction data generation unit 204MM correction data generation unit 204C C correction data generation unit 204K K correction data generation unit 205 image output Control circuit 206 Sensor unit 207 Image output means

Claims (6)

[Claims] 1. A photosensitive drum for each color of Y (yellow) M (magenta) C (cyan) K (black),
In an image forming apparatus having a plurality of image forming units for transferring an electrostatic latent image formed on a photosensitive drum of each of the YMCK colors onto a sheet to form an image, a plurality of types of registration deviations for each of the received YMCK colors A storage unit that stores a repetitive waveform pattern and a registration deviation amount in the main scanning direction for each of the YMCK colors are detected, and the detected registration deviation amount is compared with the registration deviation repetitive waveform pattern stored in the storage unit. Detecting means for detecting phase information of a plurality of types of registration deviation repeating waveform patterns for each of the YMCK colors, and phase information detected by the detecting means and registration deviation repeating waveform patterns stored in the storage means. Calculating means for calculating the resist deviation amount for each of the YMCK colors based on the above; An image forming apparatus comprising: a correction unit that performs registration correction when the image forming units of the respective colors of YMCK perform image formation based on the registration deviation amount calculated by the output unit. 2. A photosensitive drum for each color of Y (yellow) M (magenta) C (cyan) K (black),
In an image forming apparatus having a plurality of image forming units for transferring an electrostatic latent image formed on a photosensitive drum of each of the YMCK colors onto a sheet to form an image, a plurality of types of registration deviations for each of the received YMCK colors A storage unit that stores a repetitive waveform pattern and a registration deviation amount in the main scanning direction for each of the YMCK colors are detected, and the detected registration deviation amount is compared with the registration deviation repetitive waveform pattern stored in the storage unit. , Detecting means for detecting phase information and amplitude of a plurality of types of registration shift repetitive waveform patterns for each of the YMCK colors, phase information and amplitude detected by the detecting means, and resists stored in the storage means Calculation for calculating the resist shift amount for each of the YMCK colors based on the shift repeating waveform pattern An image forming unit, which comprises: a step; and a correction unit that performs registration correction when the image forming units of the respective colors of YMCK perform image formation based on the registration deviation amount calculated by the calculation unit. apparatus. 3. The image forming apparatus according to claim 1, wherein the registration shift repetitive waveform pattern stored in the storage unit is a pattern common to all the YMCK colors. 4. The calculating means further comprises setting means for setting a minimum value of the amplitude used when calculating the registration deviation amount, wherein the calculating means has the amplitude detected by the detecting means in the setting means. 3. The image forming apparatus according to claim 2, wherein the detected amplitude is not used when calculating the registration deviation amount when it is equal to or less than the set minimum value. 5. A photosensitive drum for each color of Y (yellow) M (magenta) C (cyan) K (black),
An image forming apparatus having a plurality of image forming units for forming an image by transferring an electrostatic latent image formed on a photosensitive drum of each of the YMCK colors onto a sheet, wherein each of the YMCK colors is in an initial state of the image forming apparatus. With respect to the main scanning direction, the extracting means for detecting the resist deviation amount in the main scanning direction, and extracting a plurality of types of the resist deviation repeating waveform patterns for each color of the YMCK from the detected resist deviation amount, and for each of the YMCK colors extracted by the extracting means. A storage means for storing a plurality of types of registration deviation repeated waveform patterns, and a registration deviation amount in the main scanning direction for each of the YMCK colors are detected, and the registration deviation repeated waveform pattern stored in the storage means is compared, YMCK Phase information of multiple types of registration deviation repetitive waveform patterns for each color A registration deviation amount for each color of the YMCK is calculated based on detection means for detecting the width, each phase information and amplitude detected by the detection means, and each registration deviation repeated waveform pattern stored in the storage means. An image comprising: a calculation unit; and a correction unit that performs registration correction when the image forming units of the respective colors of YMCK perform image formation based on the registration shift amount calculated by the calculation unit. Forming equipment. 6. The extracting means detects a registration deviation amount in the main scanning direction for each color of the YMCK even when the image forming apparatus is not in the initial state, and a plurality of registration amounts for each color of the YMCK are detected from the detected registration deviation amount. A type of registration shift repetitive waveform pattern is extracted, and the storage means
The image forming apparatus according to claim 5, wherein the registration deviation repeated waveform pattern newly extracted by the extraction unit is updated and stored.