JP2007219174A - Image forming apparatus and color slippage correction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which carries out color slippage correction at an appropriate timing while reducing delay in termination time for copying, and also to provide a color slippage correction method. <P>SOLUTION: The image forming apparatus is provided with: a color slippage detection means 15 for reading a pattern printed to an image carrier 7 and detecting a color shifting amount; a printing preparation action detecting means for detecting a specified printing preparation action before printing instruction is given by a user; and a color slippage correction means 16 for carrying out color slippage correction, based on the color slippage amount detected by the color slippage detection means when the printing preparation action is detected by the printing preparation action detecting means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus capable of color misregistration correction and a color misregistration correction method.

  Conventionally, a technique related to color misregistration correction at the time of image formation is known. For example, one that performs color misregistration correction every time a fixed time elapses during standby is known (see, for example, “Patent Document 1”). Also, when the user presses the copy button, the temperature change amount in the optical writing unit or the total number of printed sheets up to that point is confirmed. If they exceed a certain reference value, color misregistration correction is performed. From this, it is known to start copying.

JP 2001-228670 A

  However, in the apparatus according to Patent Document 1, there is a time difference between the timing when the user prints and the timing when the color misregistration correction is performed. Therefore, there is a possibility that color misregistration occurs again at the time of copying. Further, when the color misregistration correction is started when the copy button is pressed as described above, the user has to wait in front of the copier during the color misregistration correction.

  The present invention has been made in view of the above, and provides an image forming apparatus and a color misregistration correction method capable of performing color misregistration correction at an appropriate timing while reducing a delay in a copy end time.

  In order to solve the above-described problems and achieve the object, the invention according to claim 1 is an image forming apparatus, which reads a pattern printed on an image carrier with a sensor and detects a color misregistration amount. A detection unit, a print preparation operation detection unit that detects a predetermined print preparation operation before a print instruction by a user, and the color misregistration detection unit when the print preparation operation detection unit detects the print preparation operation. And a color misregistration correction unit that performs color misregistration correction based on the amount of color misregistration.

  According to a second aspect of the present invention, there is provided the image forming apparatus according to the first aspect, comprising: a temperature measuring unit that measures a temperature change in the optical writing unit; and an image forming unit that forms an image on printing paper. A printing number measuring unit that measures the number of printed images formed, and the color misregistration correction unit includes a case where the temperature change measured by the temperature measuring unit exceeds a predetermined reference temperature and the printing The color misregistration correction is performed when the number of printed sheets measured by the sheet number measuring unit exceeds a predetermined number of printed sheets.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, a fixing plate for fixing the original paper when the image drawn on the original paper is transferred to the printing paper is provided. Further, the print preparation operation detecting means detects an operation of the fixing plate fixing the document sheet as the print preparation operation.

  The invention according to claim 4 is the image forming apparatus according to any one of claims 1 to 3, further comprising an automatic document feeder capable of setting a plurality of printing sheets, wherein the printing preparation operation The detecting means detects an operation of setting the printing paper on the automatic document feeder as the printing preparation operation.

  According to a fifth aspect of the present invention, the image forming apparatus according to any one of the first to fourth aspects further includes a manual feed tray on which a user manually sets print paper, and the print preparation operation detection is performed. The means detects an operation of setting the printing paper on the manual feed tray as the printing preparation operation.

  The invention according to claim 6 is a color misregistration correction method, comprising: a color misregistration detecting step for detecting a color misregistration amount by reading a pattern printed on an image carrier with a sensor; and a predetermined step before a print instruction by a user. A color preparation correction based on the amount of color misregistration detected in the color misregistration detection step when the print preparatory operation is detected in the print preparatory operation detecting step and the print preparation operation detecting step is detected. And a color misregistration correction step.

  According to the first aspect of the present invention, the color misregistration detecting means reads the pattern printed on the image carrier with the sensor and detects the color misregistration amount, and the print preparation operation detecting means is the predetermined before the print instruction by the user. The color misregistration correction unit performs color misregistration correction based on the amount of color misregistration detected by the color misregistration detection unit when the print preparation operation detection unit detects the print preparation operation. That is, since the color misregistration correction is started at a timing before the actual printing is instructed, the time until the end of copying can be shortened.

  According to the invention of claim 2, the temperature measuring unit measures the temperature change in the optical writing unit, and the printed sheet number measuring unit is image-formed by the image forming unit that forms an image on the printing paper. The number of prints is measured, and the color misregistration correction unit performs printing when the temperature change measured by the temperature measurement unit exceeds a predetermined reference temperature and when the number of prints measured by the print number measurement unit is predetermined. Since the color misregistration correction is performed when the number exceeds the number, it is possible to perform an appropriate color misregistration correction.

  According to the invention of claim 3, the fixing plate fixes the original paper when transferring the image drawn on the original paper to the printing paper, and the print preparation operation detecting means is configured such that the fixing plate detects the original paper. Since the fixing operation is detected as the print preparation operation, it is possible to shorten the time until the end of copying.

  According to the invention of claim 4, the print preparation operation detecting means detects the operation of setting the print paper on the automatic document feeder capable of setting a plurality of print papers as the print preparation operation. There is an effect that the time until the time can be shortened.

  According to the fifth aspect of the present invention, the print preparation operation detecting means detects the operation of setting the print paper on the manual feed tray where the user manually sets the print paper as the print preparation operation. There is an effect that the time can be shortened.

  According to the invention of claim 6, in the color misregistration detection step, the pattern printed on the image carrier is read by the sensor to detect the color misregistration amount, and in the print preparatory operation detection step, before the print instruction by the user. In the color misregistration correction step, when the print preparatory operation is detected in the color misregistration correction step, the color misregistration correction is performed based on the color misregistration amount detected in the color misregistration detection step. As a result, the time until the end of copying can be shortened.

  Exemplary embodiments of an image forming apparatus and a color misregistration correction method according to the present invention are explained in detail below with reference to the accompanying drawings.

  FIG. 1 is a diagram illustrating a configuration in which a toner pattern is fixed to a paper conveyance belt in a copying apparatus 10 serving as an image forming apparatus. The mechanism is the same for the image carrier belt (intermediate transfer belt). The copying apparatus 10 according to the embodiment is a color image forming apparatus called a tandem type in which image forming units are arranged.

  Image forming portions for forming images of different colors (yellow: Y, magenta: M, cyan: C, black: K) are arranged in a line along the conveyance belt 2 that conveys the transfer paper 1. The conveyor belt 2 is constructed by conveyor rollers 3 and 4, one of which is a driving roller that is driven to rotate and the other is a driven roller that is driven to rotate, and is driven to rotate in the direction of the arrow by the rotation of the conveyor roller.

  A paper feed tray 5 in which the transfer paper 1 is stored is provided below the transport belt. The transfer sheet at the uppermost position among the stored transfer sheets 1 is fed at the time of image formation, is timed with each unit by the registration sensor 14 and is adsorbed onto the transport belt by electrostatic adsorption. The adsorbed transfer sheet 1 is conveyed to the first image forming unit (yellow), where yellow image formation is performed. The first image forming unit (yellow) includes a photosensitive drum 6Y, a charger 7Y, an exposure unit 8, a developing unit 9Y, and a photosensitive cleaner 10Y disposed around the photosensitive drum. The surface of the photosensitive drum 6Y is uniformly charged by the charger 7Y, and then exposed by the exposure device 8 with the laser beam 11Y corresponding to the yellow image, thereby forming an electrostatic latent image.

  The formed electrostatic latent image is developed by the developing device 9Y, and a toner image is formed on the photosensitive drum. This toner image is transferred by the transfer device 12Y at a position (transfer position) where the photosensitive drum and the transfer belt are in contact with the transfer paper, thereby forming a single color (yellow) image on the transfer paper. After the transfer, the photoreceptor drum is cleaned of unnecessary toner remaining on the drum surface by the photoreceptor cleaner 10Y to prepare for the next image formation.

  As described above, the transfer paper 1 on which the single color (yellow) is transferred by the first image forming unit (yellow) is transported to the second image forming unit (magenta) by the transport belt 2. Similarly, the toner image (magenta) formed on the photosensitive drum 6M is similarly transferred on the transfer paper. The transfer paper is further conveyed to a third image forming unit (cyan) and a fourth image forming unit (black), and a toner image formed in the same manner is transferred to form a color image. go. The transfer paper on which the color image is formed by passing through the fourth image forming unit is peeled off from the conveying belt, fixed by the fixing device 13, and then discharged.

  The sensor 15 reads a pattern of each color printed for color misregistration correction. The color misregistration amount of each color is calculated from the read value, and the color misregistration amount is corrected by the correction unit 16. Both the real-time temperature change amount in the exposure device 8 immediately after the color misregistration correction and the total number of copies and prints are recorded in a memory (not shown) provided in the copying apparatus 10.

  FIG. 2 is a diagram illustrating an external configuration of the copying apparatus 10. The copying apparatus 10 includes a manual feed tray 20, a fixed plate 30, and an automatic document feeder (ADF) 40. The manual feed tray 20 can be opened and closed as shown in the figure. The fixed plate 30 is provided so as to be openable and closable around one side as an axis. A document sheet to be copied is set under the fixed plate 30. A plurality of document sheets are set on the ADF 40 when a plurality of document sheets are continuously printed. The ADF 40 sends out a plurality of set original sheets one by one to the paper conveyance belt shown in FIG.

  The copying apparatus 10 further includes a sensor 22 that detects an opening / closing operation of the manual feed tray 20 as a print preparation operation. As another example, a sensor (not shown) may be provided that detects that a print sheet is set on the manual feed tray 20 as a print preparation operation. The copying apparatus 10 further includes a sensor 32 that detects an operation of opening the fixed plate 30 as a printing preparation operation and a sensor 42 that detects that a document sheet is set on the ADF 40.

  FIG. 3 is a flowchart showing color correction processing by the copying apparatus 10. First, when the print preparation operation is detected (step S100, Yes), the temperature change amount and the number of printed sheets stored in the memory are specified (step S102). As described with reference to FIG. 2, the print preparation operation is an operation of opening the fixing plate 30 for performing copying, an operation of setting a document on the ADF 40 for performing copying, and an operation of opening the manual feed tray 20. is there.

  When the temperature change amount specified in step S102 exceeds a predetermined reference amount and when the number of printed sheets exceeds a threshold that is a predetermined reference value (step S104, Yes), the correction unit 16 Color misregistration correction is performed (step S106). On the other hand, if both the temperature change amount and the number of printed sheets are less than the reference value (No in step S104), the process proceeds to step S108. Next, when the user presses the copy button to instruct printing (step S108, Yes), the printing process starts (step S110). This completes the color correction process.

  As described above, the present invention has been described using the embodiment, but various changes or improvements can be added to the above embodiment.

2 is a diagram illustrating a configuration in which a toner pattern is fixed on a paper conveyance belt in the copying apparatus. FIG. 1 is a diagram illustrating an external configuration of a copy apparatus 10. 4 is a flowchart illustrating color correction processing by the copy apparatus 10;

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Copy apparatus 15 Sensor 16 Correction | amendment part 20 Manual feed tray 22,32,42 Sensor 30 Fixed plate 40 ADF

Claims (6)

Color misregistration detection means for reading a pattern printed on the image carrier with a sensor and detecting a color misregistration amount;
A print preparation operation detecting means for detecting a predetermined print preparation operation before a user gives a print instruction;
A color misregistration correction unit that performs color misregistration correction based on the color misregistration amount detected by the color misregistration detection unit when the print preparation operation detecting unit detects the print preparation operation; Image forming apparatus. Temperature measuring means for measuring temperature changes in the optical writing unit;
A print number measuring means for measuring the number of printed images formed by the image forming means for forming an image on the printing paper;
The color misregistration correction unit is configured such that when the temperature change measured by the temperature measurement unit exceeds a predetermined reference temperature and the number of prints measured by the print number measurement unit exceeds a predetermined number of prints. 2. The image forming apparatus according to claim 1, wherein the color misregistration correction is performed when the image is misaligned. A fixing plate for fixing the original paper when the image drawn on the original paper is transferred to the printing paper;
The image forming apparatus according to claim 1, wherein the print preparation operation detecting unit detects an operation of the fixing plate fixing the document sheet as the print preparation operation. It further includes an automatic document feeder that can set multiple printing papers.
4. The image formation according to claim 1, wherein the print preparation operation detecting unit detects an operation of setting the printing paper on the automatic document feeder as the print preparation operation. 5. apparatus. It further includes a manual feed tray on which the user manually sets printing paper,
5. The image forming apparatus according to claim 1, wherein the print preparation operation detecting unit detects an operation of setting the printing paper on the manual feed tray as the print preparation operation. 6. A color shift detection step for reading a pattern printed on the image carrier with a sensor and detecting a color shift amount;
A print preparation operation detecting step for detecting a predetermined print preparation operation before a print instruction by the user;
A color misregistration correction step of performing color misregistration correction based on the color misregistration amount detected in the color misregistration detection step when the print preparation operation is detected in the print preparatory operation detection step. Color misregistration correction method.

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