JP2007017605A - Color image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that times needed for various adjustments cannot be shortened. <P>SOLUTION: A positioning sequence includes the steps conducted in the following order: a toner image skew correction, a main-scanning magnification correction, and main-scanning/sub-scanning registration correction. In the positioning sequence, a third adjustment, which is an adjusting sequence independent of the positioning correction, is carried out between the correction value calculation carried out for the skew correction and the pattern formation carried out for the main-scanning direction magnification correction, main-scanning direction registration correction and sub-scanning direction registration correction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a color image forming apparatus such as an electrophotographic copying machine, a printer, or a facsimile.

  Patent Document 1 discloses a color image formation in which a plurality of color toner images formed by an image process unit are superimposed and transferred onto an endless belt-shaped transfer belt to form a color image, and the color image is transferred to a transfer medium. When performing skew correction, magnification correction, and resist correction of the toner image in the device, a skew correction pattern is formed on the image process unit and transferred onto the transfer belt, and the pattern on the transfer belt is detected by a sensor. Then, a correction value for correcting the skew is calculated based on the output value of the sensor, and a physical device (such as a skew adjustment motor) is driven based on the calculated correction value to thereby skew the toner image. After correction, a magnification correction pattern is formed in the image process unit and transferred onto the transfer belt, and the pattern on the transfer belt is selected. The magnification correction value is calculated based on the output value of the sensor detected by the sensor, the magnification correction is performed based on the calculated magnification correction value, and a resist correction pattern is formed in the image process unit and transferred. A color image forming apparatus that performs transfer on a belt, detects a pattern on the transfer belt by a sensor, calculates a resist correction value based on an output value of the sensor, and performs resist correction based on the calculated resist correction value. Are listed.

JP 2002-244387

  In the color image forming apparatus, when skew correction, magnification correction, and resist correction are executed, the skew correction value is calculated because the physical device is driven (skew adjustment motor or the like) after calculating the skew correction value. It is necessary to wait for several hundred milliseconds to several seconds later before executing magnification correction and registration correction. That is, unless skew correction is performed, a subsequent pattern such as magnification correction does not become a desired pattern, and it is difficult to calculate a correct magnification correction value. The time of several hundred msec to several seconds becomes part of the waiting time, and the adjustment time for various adjustments cannot be shortened.

  An object of the present invention is to provide a color image forming apparatus capable of reducing downtime in various adjustments as a whole.

  In order to achieve the above object, the invention according to claim 1 forms a color image by superimposing and transferring a plurality of color toner images formed by the image processing unit on an endless belt-like transfer belt. In a color image forming apparatus for transferring a toner image onto a transfer medium, pattern forming means for forming a pattern for correcting a positional deviation of the toner image on the transfer belt by forming the pattern on the transfer belt, and a pattern on the transfer belt. A pattern formation position recognition unit that detects the pattern formation position based on an output value of the sensor and detects a position of the toner image based on a recognition result of the pattern formation position recognition unit. Correction value calculating means for calculating a correction value for the toner image, and a toner image level based on the correction value calculated by the correction value calculating means. And a correction unit that corrects misalignment, and performs a plurality of different processes for forming the pattern, recognizing the formation position of the pattern, calculating the correction value, and aligning each color toner image by correcting the misalignment of the toner image. The alignment process includes an alignment mode in which the alignment processing is performed in the sequence of skew correction of the toner image, magnification correction in the main scanning direction, registration correction in the main scanning direction, and registration correction in the sub scanning direction. And the alignment correction between the calculation of the correction value during execution of the skew correction and the pattern formation during execution of the main scanning direction magnification correction, main scanning direction registration correction, and sub-scanning direction registration correction. Performs a third adjustment which is an independent adjustment sequence.

  According to a second aspect of the present invention, in the color image forming apparatus according to the first aspect, the third adjustment is an adjustment of the sensor.

  According to a third aspect of the present invention, in the color image forming apparatus according to the first aspect, the third adjustment is an adjustment of a development DC bias used for image formation in the image process section.

  According to a fourth aspect of the present invention, in the color image forming apparatus according to the first aspect, the third adjustment is a charging DC bias adjustment used for image formation of the image processing unit.

  According to a fifth aspect of the present invention, in the color image forming apparatus according to the first aspect, the third adjustment is a toner density γ adjustment used for image formation in the image process section.

  According to a sixth aspect of the present invention, in the color image forming apparatus according to the first aspect, the third adjustment is a combination of any of the third adjustments of the second, third, fourth and fifth aspects. is there.

  According to the present invention, it is possible to reduce downtime in various adjustments as a whole.

  FIG. 1 shows a tandem type color image forming apparatus that is Embodiment 1 of the present invention. In this color image forming apparatus, electrophotographic image process units 1Y, 1M, 1C, and 1K that form images of different colors, for example, yellow: Y, magenta: M, cyan: C, and black: K, are transfer media. Are arranged in a line along an endless belt-like transfer belt 3 that conveys the transfer paper 2. The transfer belt 3 is stretched around a driving roller 4 and a driven roller 5, and is driven to rotate in the direction of the arrow by the driving roller 4 being rotated by a stepping motor as a driving source. A paper feed tray 6 in which the transfer paper 2 is stored is provided below the transfer belt 3. The uppermost transfer paper 2 stored in the paper supply tray 6 is fed toward the transfer belt 3 during image formation, and is attracted to the transfer belt 3 by electrostatic adsorption and is transferred by the transfer belt 3. Be transported.

  Each of the image processing units 1Y, 1M, 1C, and 1K has drum-shaped photoconductors 7Y, 7M, 7C, and 7K as image carriers, and charging disposed around the photoconductors 7Y, 7M, 7C, and 7K. 8Y, 8M, 8C, and 8K, exposure unit 9, developing units 10Y, 10M, 10C, and 10K, and photoreceptor cleaners 11Y, 11M, 11C, and 11K. The chargers 8Y, 8M, 8C, and 8K are respectively applied with a predetermined charging bias voltage from a charging bias power source, and uniformly charge the photoconductors 7Y, 7M, 7C, and 7K. Each of the developing devices 10Y, 10M, 10C, and 10K is applied with a predetermined development bias voltage (only the development DC bias voltage or a combination of the development DC bias voltage and the development AC bias voltage) from a development bias power source.

  In each of the image processing units 1Y, 1M, 1C, and 1K, the photoreceptors 7Y, 7M, 7C, and 7K are uniformly charged by the chargers 8Y, 8M, 8C, and 8K, and then Y, Exposure is performed with a plurality of light beams (laser beams) each modulated with image data of M, C, and K colors, and electrostatic latent images corresponding to the image data of the respective colors are formed. The electrostatic latent images on the photoreceptors 7Y, 7M, 7C, and 7K are developed with a two-component developer by the developing devices 10Y, 10M, 10C, and 10K, respectively, and toner images of colors Y, M, C, and K are formed. The The toner images on the photoconductors 7Y, 7M, 7C, and 7K are transferred to transfer units 12Y, 12M, and 12M at transfer positions at which the photoconductors 7Y, 7M, 7C, and 7K contact the transfer paper 2 on the transfer belt 3, respectively. A full color image is formed by sequentially transferring to the transfer paper 2 by 12C and 12K. In each of the photoconductors 7Y, 7M, 7C, and 7K, after the toner image is transferred, the residual toner is cleaned to prepare for the next image formation. The transfer paper 2 on which the full-color image is formed is peeled off from the transfer belt 3, and the full-color image is fixed by the fixing device 13 and discharged to the outside.

  FIG. 2 shows a state in which a misregistration correction pattern 14 is transferred onto the transfer belt 3 from the image processing units 1Y, 1M, 1C, and 1K when the toner image misregistration is corrected in the first embodiment. Misalignment correction patterns 14 composed of a plurality of marks transferred on both ends in the main scanning direction (width direction) on the transfer belt 3 are detected by two sensors 15 and 16, respectively. In the first embodiment, the component of the positional deviation of each color toner image transferred onto the transfer belt 3 includes skew, registration deviation in the sub-scanning direction, registration deviation in the main scanning direction, magnification error in the main scanning direction, and the like. The amount of correction of each misalignment component is calculated from the detection results of the sensors 15 and 16, and each misalignment component is corrected based on the calculation result. By this various misregistration correction processing, alignment processing of each color toner image is performed.

FIG. 3 shows a circuit unit of the first embodiment.
The output signals of the sensors 15 and 16 are amplified by an amplifier (AMP) 17, only the signal component of the pattern 14 passes through the filter 18, and is converted from analog data to digital data by the A / D converter 19. The sampling of data by the A / D converter 19 is controlled by a sampling controller 20, and the digital data from the A / D converter 19 is stored in the FIFO memory 21. After the detection of the pattern 14 is completed, the CPU 24 serving as a control unit converts the data stored in the FIFO memory 21 to I / O.
The data is loaded into the RAM 25 via the port 22 and the data bus 23. The CPU 24 performs arithmetic processing for calculating each positional deviation amount based on the data loaded in the RAM 25.

  Further, the CPU 24 receives fine adjustment amount information of each misregistration component from an operation panel (not shown) or a printer driver, and calculates a final correction value for each misregistration. The CPU 24 corrects a skew, a registration deviation in the sub-scanning direction, a registration deviation in the main scanning direction, a magnification error in the main scanning direction, and the like, which will be described later, and a mirror driving stepping motor and a document based on the correction values for each positional deviation. Control (setting) and the like of the writing control board 26 as an insertion control unit are performed. The write control board 26 controls the main resist (registration in the main scanning direction) and the sub resist (registration in the sub scanning direction) for the image data of each color of Y, M, C, and K based on the control signal from the CPU 24. And output the image data of each K color to a multi-color laser diode (LD) drive plate, and a device capable of setting the output frequency very finely, for example, a clock generator using a voltage controlled oscillator is provided for each color. ing. The clock from this clock generator is used as an image clock. In the exposure device 9, the multi-color LD drive plate drives the LD of each color with the image data of each color of Y, M, C, K from the writing control substrate 26, so that the image of each color of Y, M, C, K is obtained. A plurality of light beams (laser beams) each modulated with data are emitted, and these light beams are scanned in the main scanning direction by polygon mirrors as scanning means, respectively, and the photoreceptor 7Y is passed through the fθ lens and the folding mirror. , 7M, 7C, and 7K to scan and expose the photoreceptors 7Y, 7M, 7C, and 7K. The light beam from each polygon mirror is detected by the synchronization detector in front of the effective image area in the main scanning direction on the photoreceptors 7Y, 7M, 7C, and 7K, and a synchronization detection signal is output from the synchronization detector. .

  The CPU 24 monitors the output signals of the sensors 15 and 16 at a predetermined timing, and the light emission amount control unit 27 is based on the control signal input from the CPU 24 via the data bus 23 and the I / O port 22. , 16 control the light emission amount of the light emitting part of the sensors 15, 16 so that the output signal level of the light receiving part becomes constant. The ROM 28 stores programs for calculating the amount of misalignment and various programs, and these programs are executed by the CPU 24. The CPU 24 specifies the address of the ROM 28, the address of the RAM 25, and various input / output devices via the address bus 29.

  In the first embodiment, the skew correction of the toner image is performed by urging each color folding mirror in the exposure device 9 with a mirror driving stepping motor as a driving source to change the inclination of each color folding mirror. . FIG. 4 shows correction of writing timing in the sub-scanning direction (timing for starting writing in the sub-scanning direction on each of the photoconductors 7Y, 7M, 7C, and 7K with laser light from the exposure device 9) (registration correction in the sub-scanning direction). The timing of various signals when performing is shown. In this case, the correction resolution is 1 dot. As shown in FIG. 4, the writing control board 26 starts generation of an image area signal (image writing enable signal) in the sub-scanning direction in synchronization with the synchronization detection signal, and generates the synchronization detection signal in multiple colors. By outputting to the LD driving plate, the image writing in the sub-scanning direction is performed in accordance with the image writing enable signal in the sub-scanning direction, and the image writing enable signal in the sub-scanning direction is adjusted in synchronization with the synchronization detection signal. Registration correction in the sub-scanning direction is performed. For example, when register correction in the sub-scanning direction is performed earlier by one dot, the writing control board 26 activates the image writing enable signal in the sub-scanning direction earlier by one synchronization detection signal.

  FIG. 5 shows correction of the writing timing in the main scanning direction (timing for starting writing in the main scanning direction on each of the photoconductors 7Y, 7M, 7C, and 7K with the laser light from the exposure device 9) (registration correction in the main scanning direction). The timing of various signals when performing is shown. In this case, the correction resolution is 1 dot. The write control board 26 generates a clock that is synchronized with the falling edge of the synchronization detection signal from the clock generator and that is accurately in phase with each line, and outputs the generated clock to the multicolor LD drive plate. This clock is used as an image writing clock. The writing control board 26 outputs the image data of each color Y, M, C, K to the multi-color LD drive plate in synchronization with the image writing clock to perform image writing. Generation of a signal (image writing enable signal) is also started in synchronization with the image writing clock so that writing in the main scanning direction is performed in accordance with the image area signal in the main scanning direction, and image writing enable signal in the main scanning direction is performed. Is adjusted in synchronization with the image writing clock to perform registration correction in the main scanning direction. For example, when register correction in the main scanning direction is performed earlier by one dot, the writing control board 26 activates the image writing enable signal in the main scanning direction earlier by one image writing clock.

The writing control board 26 performs magnification correction in the main scanning direction by controlling the clock generator based on a control signal from the CPU 24 and changing the frequency of the image writing clock.
FIG. 6 shows a toner image positional deviation correction processing flow according to the first embodiment.
The toner image misregistration correction process according to the first exemplary embodiment is started in step S001, and the CPU 24 outputs a skew adjustment pattern on the transfer belt 3 in step S002. That is, the write control board 26 outputs a skew adjustment pattern signal of each color from the pattern signal generator to the multi-color LD drive plate based on a control signal from the CPU 24, thereby forming a toner image from the image data. In the same manner as described above, a skew adjustment pattern for each color is formed on each of the photoreceptors 7Y, 7M, 7C, and 7K. The skew adjustment patterns for each color are transferred onto the transfer belt 3 in a shifted manner. A skew adjustment pattern 14 of each color is formed at both ends.

Next, the skew adjustment pattern 14 transferred onto the transfer belt 3 in step S003 is detected by the sensors 15 and 16, and the output signals of the sensors 15 and 16 are the amplifier 17, the filter 18, and the A / D converter. The data is stored in the FIFO memory 21 via 19. The CPU 24 loads the data stored in the FIFO memory 21 into the RAM 25 via the I / O port 22 and the data bus 23. Next, in step S204, the CPU 24 calculates the skew correction amount of the skew adjustment pattern 14 using the data stored in the FIFO memory 21 in step S003, so that the toner image transferred onto the transfer belt 3 is calculated. The amount of skew correction is calculated.
After calculating the skew correction value, the CPU 24 performs skew correction by driving the skew motor (the mirror driving stepping motor) based on the skew correction value in step S005, and the effect of the skew is determined in step S006. Perform other adjustment operations that are not affected.

  After completing the operations of steps S005 and S006, the CPU 24 outputs the magnification, the main scanning direction registration, and the sub-scanning direction registration adjustment pattern on the transfer belt 3 in step S007. That is, the write control board 26 receives the pattern signals for main scanning direction magnification, main scanning direction registration, and sub-scanning direction registration adjustment for each color from the pattern signal generator based on the control signal from the CPU 24. In the same manner as the toner image formation by the image data, the main scanning direction magnification, the main scanning direction resist, and the sub-scanning direction resist adjustment pattern for each color are formed on each of the photoreceptors 7Y, 7M, 7C, and 7K. The main scanning direction magnification, the main scanning direction resist, and the sub-scanning direction resist adjustment pattern of each color are transferred onto the transfer belt 3 in a shifted manner, whereby the main scanning direction magnification and the main scanning direction are transferred to both ends of the transfer belt 3. A resist and a sub-scanning direction resist adjustment pattern 14 are formed.

  Next, the main scanning direction magnification, the main scanning direction registration, and the sub scanning direction registration adjustment pattern 14 transferred onto the transfer belt 3 in step S008 are detected by the sensors 15 and 16, and the output signals of the sensors 15 and 16 are detected. Is stored in the FIFO memory 21 via the amplifier 17, the filter 18, and the A / D converter 19. The CPU 24 loads the data stored in the FIFO memory 21 into the RAM 25 via the I / O port 22 and the data bus 23. Next, in step S009, the CPU 24 uses the data stored in the FIFO memory 21 in step S008, and the main scanning direction magnification correction value of the main scanning direction magnification, the main scanning direction registration, and the sub-scanning direction registration adjustment pattern 14. By calculating the main scanning direction registration correction value and the sub scanning direction registration correction amount, the main scanning direction magnification correction value, the main scanning direction registration correction value, and the sub scanning direction registration correction of the toner image transferred onto the transfer belt 3 are calculated. Calculate the amount. Next, in step S010, the CPU 24 performs magnification correction based on the main scanning direction magnification correction value as described above, and performs main scanning direction registration correction based on the main scanning direction registration correction value and the sub-scanning direction registration correction amount. Correction and sub-scanning direction registration correction are performed as described above, and the sequence is completed.

  In the first embodiment, it is possible to reduce the overall adjustment operation time by executing the skew motor drive (skew correction) and other adjustment operations in parallel, thereby reducing the overall downtime of various adjustments. can do.

FIG. 7 shows a toner image misregistration correction processing flow according to the second embodiment of the present invention.
In the second embodiment, as shown in FIG. 7 in the first embodiment, the CPU 24 adjusts the sensors 15 and 16 (Vsg adjustment) as another adjustment operation not affected by the skew in step S006 (S106). I do. That is, the CPU 24 fetches data stored in the FIFO memory 21 from the sensors 15 and 16 via the amplifier 17, the filter 18, and the A / D converter 19 via the I / O port 22 and the data bus 23, and Based on the data, the light emitting portions of the sensors 15 and 16 are controlled via the data bus 23, the I / O port 22, and the light emission amount control unit 27, so that the background portion on the transfer belt 3 (photosensitive on the transfer belt 3 is exposed). The light emitting unit light emission amounts of the sensors 15 and 16 are adjusted so that the light receiving unit output signal level of the sensors 15 and 16 with respect to the toner images on the bodies 7Y, 7M, 7C, and 7K is a set value. Note that steps S101 to S111 in the second embodiment correspond to steps S001 to S011 in the first embodiment.

  According to the second embodiment, it is possible to reduce the overall adjustment operation time by executing the skew motor driving (skew correction) and the Vsg adjustment operation (adjustment of the sensors 15 and 16) in parallel. It is possible to reduce downtime in various adjustments as a whole.

FIG. 8 shows a toner image misregistration correction processing flow according to the third embodiment of the present invention.
In the third embodiment, as shown in FIG. 8 in the first embodiment, the CPU 24 controls the development bias power supply and controls the development DC as another adjustment operation not affected by the skew in step S006 (S206). Adjust the bias voltage. Note that steps S201 to S211 in the third embodiment correspond to steps S001 to S011 in the first embodiment.

  According to the third embodiment, it is possible to reduce the overall adjustment operation time by executing the skew motor driving (skew correction) and the development DC bias voltage adjustment operation in parallel. Downtime can be reduced.

FIG. 9 shows a toner image misalignment correction processing flow according to the fourth embodiment of the present invention.
In the fourth embodiment, as shown in FIG. 9 in the first embodiment, the CPU 24 performs another adjustment operation not affected by the skew in step S006 (S306) as shown in FIG. To adjust the charging DC bias voltage. Note that steps S301 to S311 in the fourth embodiment correspond to steps S001 to S011 in the first embodiment.

  According to the fourth embodiment, it is possible to reduce the adjustment operation time as a whole by executing the skew motor driving (skew correction) and the charging DC bias adjustment operation in parallel, and reducing the overall adjustment. Time can be reduced.

FIG. 10 shows a toner image misalignment correction processing flow according to the fifth embodiment of the present invention.
In the fifth embodiment, as shown in FIG. 10 in the first embodiment, the CPU 24 performs an image processing unit as another adjustment operation not affected by the skew in step S006 (S406) as shown in FIG. The toner densities γ of the developing units 10Y, 10M, 10C, and 10K used for 1Y, 1M, 1C, and 1K image formation are adjusted. Note that steps S401 to S411 in the fifth embodiment correspond to steps S001 to S011 in the first embodiment.

  According to the fifth embodiment, it is possible to reduce the adjustment operation time as a whole by executing the skew motor driving (skew correction) and the toner density γ adjustment operation in parallel, and the downtime of the entire adjustment. Can be reduced.

  In the sixth embodiment of the present invention, the Vsg adjustment (adjustment of the sensors 15 and 16) in the second embodiment, the adjustment operation in the third embodiment, as other adjustment operations that are not affected by the skew in step S006 in the first embodiment. A plurality of combinations (arbitrary combinations) of development DC bias adjustment, charging DC bias adjustment of Embodiment 4 and toner density γ adjustment of Embodiment 5 are performed.

  According to the fifth embodiment, the skew motor drive (skew correction) and the third adjustment operation are executed in parallel, and the third adjustment operation includes Vsg adjustment (adjustment of the sensors 15 and 16) and development DC bias adjustment. By adjusting the charging DC bias adjustment and the toner density γ adjustment arbitrarily, it is possible to reduce the adjustment operation time as a whole, and to reduce the downtime of all the adjustments.

1 is a cross-sectional view showing Embodiment 1 of the present invention. FIG. 3 is a perspective view showing a state in which a misregistration correction pattern is transferred from an image process unit onto a transfer belt during toner image misregistration correction in the first embodiment. FIG. 3 is a block diagram showing a circuit unit of the first embodiment. 3 is a timing chart showing timings of various signals when correcting the writing start timing in the sub-scanning direction according to the first embodiment. FIG. 6 is a diagram illustrating timings of various signals when correcting the writing timing in the main scanning direction according to the first embodiment. 3 is a flowchart showing a toner image positional deviation correction process flow according to the first embodiment. 10 is a flowchart illustrating a toner image positional deviation correction processing flow according to the second exemplary embodiment of the present invention. 14 is a flowchart illustrating a toner image positional deviation correction processing flow according to the third exemplary embodiment of the present invention. 10 is a flowchart illustrating a toner image positional deviation correction processing flow according to the fourth exemplary embodiment of the present invention. 10 is a flowchart illustrating a toner image misregistration correction processing flow according to a fifth exemplary embodiment of the present invention.

Explanation of symbols

1Y, 1M, 1C, 1K Image processing section 3 Transfer belt 15, 16 Sensor 21 FIFO memory 24 CPU
26 Write Control Board 27 Light Emission Control Unit

Claims (6)

In a color image forming apparatus that forms a color image by superimposing and transferring a plurality of color toner images formed by an image processing unit on an endless belt-like transfer belt, and transferring the color image to a transfer medium.
Pattern forming means for forming a pattern for correcting the positional deviation of the toner image in the image process unit and transferring the pattern onto the transfer belt;
Pattern formation position recognition means for detecting a pattern on the transfer belt by a sensor and recognizing the formation position of the pattern based on an output value of the sensor;
Correction value calculating means for calculating a correction value for correcting a positional deviation of the toner image based on a recognition result of the pattern forming position recognition means;
Correction means for correcting a positional deviation of the toner image based on the correction value calculated by the correction value calculation means,
An execution mode for executing a plurality of different processes for the registration processing of each color toner image by forming the pattern, recognizing the formation position of the pattern, calculating the correction value, and correcting the misregistration of the toner image;
The alignment processing is performed by performing the skew correction in an alignment sequence having an order executed in the sequence of skew correction of the toner image, main-scanning direction magnification correction, main-scanning direction registration correction, and sub-scanning direction registration correction. During the calculation of the correction value at the time and the pattern formation during execution of the magnification correction in the main scanning direction, the registration correction in the main scanning direction, and the registration correction in the sub-scanning direction are adjustment sequences independent of the alignment correction. A color image forming apparatus that performs a third adjustment.   2. The color image forming apparatus according to claim 1, wherein the third adjustment is adjustment of the sensor.   2. The color image forming apparatus according to claim 1, wherein the third adjustment is an adjustment of a developing DC bias used for image formation of the image processing unit.   The color image forming apparatus according to claim 1, wherein the third adjustment is a charging DC bias adjustment used for image formation of the image processing unit.   The color image forming apparatus according to claim 1, wherein the third adjustment is a toner density γ adjustment used for image formation of the image processing unit. The color image forming apparatus according to claim 1, wherein the third adjustment is a combination of any of the third adjustments according to claim 2, 3, 4, and 5.

Images