JP2009180947A - Image forming apparatus, method of controllin image forming apparatus, and control program for image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of regulating easily an image. <P>SOLUTION: An image regulation pattern 15 is transferred onto a paper sheet 11. The image regulation pattern 15 is detected using image regulation pattern reading sensors 14A, 14B provided between a transfer part and a fixing part. The paper sheet 11 passes thereafter through a position of a fixing roller 6A. The image regulation pattern 15 is removed therein from the paper sheet, by image pattern removal parts 16A, 16B on the fixing roller 6A. Toner is fixed in a position not provided with the image pattern removal parts 16A, 16B. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, an image forming apparatus control method, and an image forming apparatus control program, and more particularly to an image forming apparatus capable of easily adjusting an image, an image forming apparatus control method, and image formation. The present invention relates to a device control program.

  Some electrophotographic image forming apparatuses (MFP (Multi Function Peripheral), facsimile machines, copiers, etc.) have a color printing function.

  In a color image forming apparatus, as a method of superimposing colors, there are an intermediate transfer method and a direct transfer method. The intermediate transfer method is a method in which colors are superimposed on an intermediate transfer member (belt, drum) and then transferred onto a sheet (an example of a recording medium) as a final transfer member. The direct transfer method is a method of directly superimposing colors on paper. In the direct transfer method, the paper is conveyed while being back-up attracted to a belt or a drum. Thereby, the stability of conveyance can be maintained. The image forming apparatus transfers the toner image onto the sheet while conveying the sheet.

  In the color image forming apparatus, registration control, which is one of stabilization control, is performed separately from the printing sequence. Registration control is control for detecting the amount of color misregistration in the main scanning direction and the sub-scanning direction and feeding it back to the image forming unit. The amount of color misregistration is detected by printing (printing) a pattern (resist pattern) and reading it with a sensor (resist sensor) in the machine. By performing such stabilization control, it is possible to stabilize color alignment accuracy and prevent color misregistration.

  Usually, in the intermediate transfer system, the resist pattern is printed on an intermediate transfer belt or drum. In the direct transfer method, printing is performed on a belt or drum that sucks back a sheet.

  There has also been proposed a method of printing a resist pattern on a sheet so that the user can visually observe and adjust the pattern.

  Patent Document 1 below discloses a technique for printing a test pattern that can be visually confirmed on paper. This makes it possible to confirm the correction amount by devising the pattern. Since the user can visually check the pattern and adjust the correction amount, it is possible to reduce the cost by omitting the registration sensor.

  On the other hand, in a color image forming apparatus, a beltless color tandem system that does not use an intermediate transfer belt or a direct transfer belt has been proposed. In the beltless color tandem system, a plurality of pairs of photoconductors and transfer rollers are arranged. The sheet is conveyed only by the pair of the photoconductor and the transfer roller. In such a system, there is no belt or drum for printing a resist pattern for registration control. Therefore, for registration control, a method of printing a resist pattern on a sheet as a final transfer member can be considered.

Patent Document 2 below discloses an image forming apparatus that removes a registration control mark (registration pattern) printed on a sheet before fixing. According to this technique, it is not necessary for the user to visually check the resist pattern and adjust the correction amount. Also, paper is not consumed.
JP 2001-109218 A JP 2007-79296 A

  In the technique of Patent Document 1, it takes time and effort for the user to visually observe and adjust the resist pattern. Further, there is a disadvantage that paper is consumed for registration adjustment. Although a method of printing a resist pattern on paper and reading it with a sensor in the apparatus is conceivable, the disadvantage of consuming paper is not improved.

  In the technique of Patent Document 2, a member for removing a resist pattern needs to be specially provided, so that there is a disadvantage that the apparatus becomes large and the cost is increased.

  The present invention has been made to solve such problems, and provides an image forming apparatus, an image forming apparatus control method, and an image forming apparatus control program capable of easily adjusting an image. The purpose is that.

  In order to achieve the above object, according to one aspect of the present invention, an image forming apparatus includes a forming unit that forms an image adjustment pattern on a recording medium, and a detection unit that detects the image adjustment pattern formed by the forming unit. And a fixing unit having a function of fixing an image on the recording medium and a function of removing an image adjustment pattern from the recording medium.

  Preferably, the forming unit includes a plurality of image forming units corresponding to each of the plurality of colors, and the image forming apparatus includes a plurality of image forming units corresponding to each of the plurality of colors based on the detection result of the detecting unit. Control means for controlling is further provided.

  Preferably, the plurality of image forming units corresponding to each of the plurality of colors are arranged side by side, and the image forming apparatus transfers the toner images of the respective colors while conveying the paper as the recording medium to the plurality of image forming units. A color image is formed by sequential transfer.

  Preferably, the detecting unit is provided between the forming unit and the fixing unit.

  Preferably, the image adjustment pattern is formed on the same recording medium as the recording medium on which the image is printed.

  Preferably, the image adjustment pattern is formed at an end portion of a recording medium on which an image is printed and outside the user print area.

  Preferably, the image forming apparatus further includes setting means for setting a mode for forming an image adjustment pattern, and the image adjustment pattern is formed on the recording medium in the mode for forming the image adjustment pattern. Then, it is removed at the fixing unit.

  Preferably, the fixing unit removes the image adjustment pattern from the recording medium by a low temperature offset or a high temperature offset for fixing.

  Preferably, the fixing unit removes the image adjustment pattern from the recording medium by applying a reverse transfer voltage.

  Preferably, the pattern for image adjustment is a pattern in which the leading edge, the trailing edge, or both of the pattern is sharpened.

  According to another aspect of the present invention, a method for controlling an image forming apparatus includes a forming step of forming an image adjustment pattern on a recording medium, a detection step of detecting an image adjustment pattern formed by the forming unit, and a recording And a step of removing the image adjustment pattern from the recording medium by a fixing unit having a function of fixing the image on the medium and a function of removing the image adjustment pattern from the recording medium.

  According to another aspect of the present invention, a control program for an image forming apparatus includes a forming step for forming an image adjustment pattern on a recording medium, a detection step for detecting an image adjustment pattern formed by the forming unit, and a recording The fixing unit having a function of fixing the image on the medium and a function of removing the image adjustment pattern from the recording medium causes the computer to execute the step of removing the image adjustment pattern from the recording medium.

  According to these inventions, it is possible to provide an image forming apparatus, an image forming apparatus control method, and an image forming apparatus control program capable of easily adjusting an image.

  Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described.

  The image forming apparatus is a tandem color printer that prints all colors of YMCK (yellow, magenta, cyan, black) in one cycle. In a tandem color printer, photoconductors of a plurality of colors are arranged in series. A color image is formed by sequentially transferring the toner images of the respective colors from the photoreceptor to the paper while the paper is being passed and conveyed.

  That is, the image forming apparatus employs a belt-less tandem system that does not use an intermediate transfer belt or a direct transfer belt.

  [First Embodiment]

  FIG. 1 is a diagram illustrating a hardware configuration of the image forming apparatus according to the first embodiment of the present invention.

  Referring to the drawing, an image forming apparatus 1 includes a paper feed cassette 2, a paper feed unit 3, a Y color photoconductor 4A, an M color photoconductor 4B, a C color photoconductor 4C, and a K color photoconductor 4D. Y color transfer roller (transfer portion) 5A, M color transfer roller (transfer portion) 5B, C color transfer roller (transfer portion) 5C, K color transfer roller (transfer portion) 5D, fixing portion 6, A paper discharge unit 7.

  The paper feed cassette 2 contains paper for forming an image. The presence or absence of paper is detected by a sensor. If no paper is set or if paper runs out during printing, the sensor detects the situation and informs the user via a display panel or the like. A paper feed unit 3 is provided in front of the paper feed cassette 2 (on the right side in the figure) to send out the paper in the paper feed cassette 2 to an image forming unit (image writing unit). The image forming apparatus 1 includes a controller 51 including a CPU that controls the apparatus.

  The image forming apparatus 1 is used by being connected to a computer directly or via a network. Image data to be printed on paper is transferred from the computer to the controller 51 in the image forming apparatus. The image forming unit forms a latent image on the Y color photoconductor 4A based on the transferred image data. The developing unit forms an image on the Y-color photoconductor 4A with a developer according to the latent image. The image formed by the developer formed on the Y color photoreceptor 4A is transferred to the paper by the Y color transfer roller 5A. This sheet is the sheet in the sheet feeding cassette 2 sent out from the sheet feeding unit 3. The sheet is controlled by the sheet feeding unit 3 so that the position of the image with respect to the sheet is appropriate, and is conveyed to the Y color transfer roller 5A. Similarly, transfer processing by the M color photoconductor 4B and the M color transfer roller 5B, transfer processing by the C color photoconductor 4C and the C color transfer roller 5C, and transfer by the K color photoconductor 4D and the K color transfer roller 5D. Processing is performed for each color continuously. The sheet on which the developer has been transferred by the color transfer rollers 5A to 5D is sent to the fixing unit 6 where heat and pressure are applied. The developer on the paper passes through the fixing unit 6 and develops color as soon as it is fixed on the paper. Thereafter, the paper is discharged to the paper discharge unit 7. Thereby, the image formation is completed.

  FIG. 2 is a diagram showing a configuration for performing registration control included in the image forming apparatus of FIG.

  The transfer roller 5 sandwiches and conveys the paper 11 relative to the photoreceptor 4.

  Here, the photoconductor 4 is any one of the color photoconductors 4A to 4D in FIG. 1 (preferably the K color photoconductor 4D). The transfer roller 5 is any one of the color transfer rollers 5A to 5D (preferably the K color transfer roller 5D) in FIG. When the photoreceptor 4 is a K-color photoreceptor 4D, the transfer roller 5 is a K-color transfer roller 5D. The photoconductor 4 and the transfer roller 5 correspond to each color.

  The fixing unit 6 of FIG. 1 includes a fixing roller (heating roller) 6A, a fixing pressure roller 6B, and a fixing cleaning roller 6C. The fixing pressure roller 6B sandwiches and conveys the paper 11 relative to the fixing roller 6A. The fixing cleaning roller 6C contacts the fixing roller 6A and collects the removed image adjustment pattern 15 (see FIG. 3) in the machine.

  The sheet 11 passes through the sheet passing path while the toner image is transferred by the photoreceptor 4 and the transfer roller 5. When image adjustment (registration adjustment) is performed, the image adjustment pattern 15 (FIG. 3) is also transferred to the paper 11. The image adjustment pattern 15 is a registration control mark (registration pattern) printed on a sheet. Density adjustment and color misregistration detection are performed using the image adjustment pattern 15.

  An image adjustment pattern reading sensor 14 is installed on the sheet conveyance path between the photoconductor 4 and the fixing roller 6A. When the image adjustment pattern 15 is transferred onto the paper 11, the image adjustment pattern reading sensor 14 reads the toner image of the image adjustment pattern 15. The read data is sent to the controller 51, and fine adjustment of the print position in the image forming unit for each color is performed.

  Thereafter, the toner image is fixed on the sheet 11 by the fixing roller 6A and the fixing pressure roller 6B. At the same time, the image adjustment pattern 15 is removed. The removal process of the image adjustment pattern 15 will be described with reference to FIG. The removed image adjustment pattern 15 is collected by the fixing cleaning roller 6C. The paper 11 is discharged from the paper discharge unit 7 and the image formation is completed.

  FIG. 3 is a view of a part of the configuration of FIG. 2 as viewed from the fixing roller 6A side.

  Image adjustment pattern removal units 16A and 16B exist on the left and right sides of the fixing roller 6A. An image to be printed by the user is formed on the center of the paper 11 by the photoreceptor 4. The image formed by the unfixed toner 12A is sent together with the paper 11 in the upward direction (arrow direction) in the figure. The unfixed toner 12A is fixed on the paper 11 by the fixing roller 6A and becomes the fixed toner 12B. In addition, image adjustment patterns 15 are drawn on the left and right sides of the paper 11. Image adjustment pattern reading sensors 14A and 14B are arranged on the left and right sides so that the image adjustment patterns 15 drawn on the left and right sides of the paper can be read.

  Here, the image adjustment pattern 15 is a set of marks printed in each color of CMYK. The image adjustment pattern reading sensors 14A and 14B measure the color misregistration amount and the like by reading the marks of the respective colors.

  The sheet 11 passes through the position of the photoreceptor 4 while being transferred with an image adjustment pattern 15 made of unfixed toner 12A and unfixed toner. On the paper 11, a pattern output by the user (an image that the user wants to print) is drawn (transferred) at the center of the paper, and image adjustment patterns 15 are drawn at both ends thereof.

  The sheet 11 is conveyed in the direction of the fixing roller 6A on the downstream side. At that time, the image adjustment patterns 15 transferred to the left and right ends of the paper 11 are read by the image adjustment pattern reading sensors 14A and 14B.

  Thereafter, the sheet 11 passes between the fixing roller 6A and the fixing pressure roller 6B while fixing the unfixed toner 12A. At this time, the image adjustment pattern 15 is erased from the paper 11 by the image pattern removal units 16A and 16B on the fixing roller 6A. Therefore, the image adjustment pattern 15 does not exist on the paper 11 after passing through the fixing roller 6A.

  That is, the fixing roller 6A has a function of fixing the toner passing through the position, but has a function of removing unfixed toner from the paper 11 at the positions of the image adjustment pattern removing units 16A and 16B. The removed toner is collected by the fixing cleaning roller 6C.

  Here, the image adjustment pattern 15 is printed on both side edges (outside the user print area) on the same paper 11 as the paper on which the user prints image data. Therefore, image adjustment can be performed simultaneously with normal printing. Thus, it is not necessary to pass the sheet only for registration control.

  Further, since the image adjustment amount can be detected in the machine, it is not necessary to make the user visually check the image adjustment pattern 15 and manually adjust the image adjustment amount. Thereby, it is possible to save the user's trouble while ensuring the image position accuracy and color alignment accuracy in the main scanning and sub-scanning directions.

  Furthermore, in the present embodiment, an independent device for removing the image adjustment pattern 15 is not specially provided. In the present embodiment, the image adjustment pattern 15 can be removed by the image adjustment pattern removal units 16A and 16B provided in the fixing unit 6. As a result, it is possible to prevent an increase in cost and size of the apparatus.

  FIG. 4 is a graph showing the relationship between the fixing temperature and the fixing ratio.

  Referring to the drawing, when the fixing temperature (fixing roller temperature) is low, the fixing ratio (the ratio of toner to be fixed) is also low. When the fixing temperature is too low, the toner is not fixed on the paper, and the toner is offset on the fixing roller. This is called a low temperature offset.

  As the fixing temperature increases, the fixing ratio starts to increase. When the fixing temperature rises and reaches a certain temperature, the fixing ratio is stabilized. This temperature range is a region where toner can be normally fixed.

  If the fixing temperature is further increased, the fixing ratio is decreased. This is because the toner is offset to the fixing roller even when the fixing temperature is too high. This is called a high temperature offset.

  Using the phenomenon occurring between the fixing temperature and the fixing ratio, the image adjustment pattern is removed and collected by the fixing roller 6A.

  As shown in FIG. 3, when image data to be printed by the user and the image adjustment pattern 15 are transferred onto the same paper 11 (an area on which the image data to be printed by the user is transferred on the paper 11, and an image adjustment pattern) 15), the temperature of the fixing roller 6A needs to be partially changed. Specifically, the temperature of the image adjustment pattern removal units 16A and 16B provided at both ends of the fixing roller 6A is set to a low temperature or a high temperature. Accordingly, a low temperature offset or a high temperature offset is generated, and the image adjustment pattern 15 in contact with the image adjustment pattern removal units 16A and 16B is not fixed on the paper 11. Further, the image adjustment pattern 15 is removed from the sheet 11 by making the temperature of the image adjustment pattern removal units 16A and 16B different from the temperature of the other portions of the fixing roller 6A.

  FIG. 5 is a diagram illustrating a specific example of the image adjustment pattern.

  Refer to the figure

  (A) is an example of an image adjustment pattern for measuring the writing position of each color in the sub-scanning direction,

  (B) is an example of an image adjustment pattern for measuring the writing position of each color in the main scanning and sub-scanning directions;

  (C) is an example of an image adjustment pattern for measuring the writing position of each color in the main scanning and sub-scanning directions.

  In the present embodiment, any of the patterns (a) to (c) may be formed. In any of the patterns, the shift amount of the print position of each color can be measured by forming the CMYK color marks on the paper synchronously.

  In particular, in the present embodiment, as shown in (c), it is preferable to use a pattern in which the toner is not a line but has a certain shape with a certain area. As described with reference to FIG. 4, when the image adjustment pattern 15 is removed and collected using the fixing temperature, the pattern (c) is easy to remove. This is because the toner is more easily condensed and removed than the discrete line-shaped patterns (a) and (b), particularly in the case of the lump-shaped pattern. In addition, the pattern can be easily removed from the paper by making the leading edge, the trailing edge, or both of the marks of the pattern sharp.

  [Second Embodiment]

  Next, an image forming apparatus according to a second embodiment of the present invention will be described. The hardware configuration of the image forming apparatus in the second embodiment is almost the same as that in the first embodiment. Here, only the differences of the second embodiment from the first embodiment will be described.

  In the present embodiment, in addition to the first embodiment, the image forming apparatus 1 can set an image adjustment pattern printing mode. In the image adjustment pattern printing mode, the image forming apparatus 1 does not print the image adjustment pattern 15 on the same paper as that on which the user prints image data, but only prints the image adjustment pattern 15.

  The apparatus is configured so that the user can select a normal user print mode or an image adjustment pattern print mode using an operation panel or the like. Here, the operation when the user selects the image adjustment pattern printing mode and uses the image forming apparatus 1 will be described.

  FIG. 6 is a view of a part of the configuration for performing the registration control in the image forming apparatus provided with the image adjustment pattern printing mode as seen from the fixing roller 6A side.

  Unlike the first embodiment, the image adjustment pattern removal units 16A and 16B are not attached to the left and right sides of the fixing roller 6A. An image adjustment pattern 15 is formed by the photosensitive member 4 at each of the left and right ends of the sheet 11. Image adjustment pattern reading sensors 14A and 14B are arranged on the left and right sides so that the image adjustment patterns 15 drawn on the left and right sides of the paper can be read.

  The sheet 11 passes between the photoconductor 4 and the transfer roller 5 while the image adjustment pattern 15 is transferred. Image adjustment patterns 15 are drawn on both ends of the paper 11.

  The sheet 11 is conveyed in the direction of the fixing roller 6A on the downstream side. At that time, the image adjustment patterns 15 transferred to the left and right ends of the paper 11 are read by the image adjustment pattern reading sensors 14A and 14B.

  Thereafter, the paper 11 passes between the fixing roller 6A and the fixing pressure roller 6B. At this time, the image adjustment pattern 15 is erased from the paper 11. Therefore, the image adjustment pattern 15 does not exist on the paper 11 after passing through the fixing roller 6A. The sheet 11 becomes a blank sheet and is discharged. That is, in the image adjustment pattern printing mode, the fixing roller 6 </ b> A has a function of removing unfixed toner from the paper 11. The removed toner is collected by the fixing cleaning roller 6C.

  Here, since the image adjustment pattern 15 is erased from the paper 11, the paper 11 returns to the blank state. Therefore, the sheet 11 after the image adjustment pattern 15 is erased can be reused by the user after being discharged. By reusing the adjustment paper, it is possible to prevent waste paper consumption.

  Also in the present embodiment, either the high temperature offset or the low temperature offset is used for erasing the image adjustment pattern 15. When the normal user print mode and the image adjustment pattern print mode are separated at the timing as in the present embodiment (when the image that the user wants to print and the image adjustment pattern 15 are not simultaneously transferred onto the paper 11 ), A high temperature offset or a low temperature offset is generated by changing the temperature of the entire fixing roller 6A. Thereby, the image adjustment pattern 15 can be erased.

  In the normal user print mode, the temperature of the entire area of the fixing roller 6A is set to a temperature suitable for fixing.

  As in the first embodiment, when the image to be printed is fixed by the user and only the image adjustment pattern 15 is erased, it is necessary to change the temperature of the image adjustment pattern removal units 16A and 16B on the fixing roller 6A. there were. However, in the present embodiment, it is only necessary to erase the image adjustment pattern 15, so there is no need to change the temperature for each portion of the fixing roller 6 </ b> A.

  FIG. 7 is a flowchart showing the temperature control process of the fixing roller in accordance with the mode in the second embodiment.

  In order to remove the image adjustment pattern 15 using the fixing roller, it is necessary to change the temperature of the fixing roller 6A between the normal user print mode and the image adjustment pattern print mode. Therefore, the mode selected by the user is determined, and the temperature of the fixing roller 6A is manipulated so as to correspond to the selected mode.

  When using the image forming apparatus 1, the user selects a normal user print mode or an image adjustment pattern print mode from the operation panel or the like. In step S101, the controller 51 determines which mode has been selected.

  If the image adjustment pattern printing mode is selected, the temperature of the fixing roller 6A is set to T1 in step S103. Specifically, the high temperature offset or the low temperature offset is generated by changing the temperature of the entire area of the fixing roller 6A. Thereby, the image adjustment pattern 15 is removed from the paper 11.

  If the normal user print mode is selected, the temperature of the fixing roller 6A is set to T2 in step S105. Specifically, the temperature of the entire area of the fixing roller 6A is set to a temperature suitable for fixing.

  [Third Embodiment]

  Next, an image forming apparatus according to a third embodiment of the present invention will be described. The hardware configuration of the image forming apparatus in the third embodiment is substantially the same as that in the first and second embodiments. Here, only the differences of the third embodiment from the first and second embodiments will be described.

  Even if the temperature of the fixing roller 6A is manipulated to generate the high temperature offset or the low temperature offset in order to remove the image adjustment pattern 15 as in the first and second embodiments, the image adjustment pattern 15 on the sheet is generated. May not be completely removed.

  In order to prevent such a situation, in the third embodiment, a reverse transfer voltage for image adjustment pattern removal is applied to the fixing roller 6A, and removal of the image adjustment pattern 15 by the reverse transfer voltage is used in combination. The reverse transfer voltage for image adjustment pattern removal is to reversely transfer the toner transferred to the paper by the photoreceptor to the fixing roller.

  By using the reverse transfer voltage for image adjustment pattern removal, the image adjustment pattern on the paper is removed without being fixed. Thereby, the image adjustment pattern can be more reliably removed.

  FIG. 8 is a diagram illustrating a configuration of an image forming apparatus according to the third embodiment.

  When printing processing is performed in the present embodiment, unfixed toner including the image adjustment pattern 15 is transferred onto the paper 11 from the photoconductors 4A to 4D. Transfer voltages 17Y, 17M, 17C, and 17K are applied to the color transfer rollers 5A to 5D that face the color photosensitive members 4A to 4D. Unfixed toner is transferred onto the paper 11 from the photoconductors 4A to 4D by the transfer voltages 17Y, 17M, 17C, and 17K applied to the color transfer rollers 5A to 5D.

  Then, the sheet 11 on which the unfixed toner is transferred is sent to the fixing unit 6. In the fixing unit 6, in order to remove the image adjustment pattern 15 from the paper 11, the reverse transfer voltage 17F for image adjustment pattern removal is applied to the fixing roller 6A. The image adjustment pattern 15 is reversely transferred from the sheet 11 to the fixing roller 6A by the image adjustment pattern removal reverse transfer voltage 17F. As a result, the image adjustment pattern 15 moves to the fixing roller and is removed from the paper 11 during toner fixing.

  When the paper 11 is divided into the user print area and the image adjustment pattern print area as in the first embodiment (when the user wants to print the image and the image adjustment pattern 15 simultaneously on the same paper) ) Needs to be configured so that the reverse transfer voltage 17F for image adjustment pattern removal is partially applied to both ends of the fixing roller 6A. This is to remove only the image adjustment pattern 15 transferred to both ends of the paper 11.

  That is, the reverse transfer voltage 17F for image adjustment pattern removal is applied only to the image pattern removal units 16A and 16B in the configuration of FIG.

  Also, as in the second embodiment, when the normal user print mode and the image adjustment pattern print mode are separated at the timing (the image that the user wants to print and the image adjustment pattern 15 are placed on the same sheet. In the case of not printing at the same time, the reverse transfer voltage 17F for image adjustment pattern removal may be applied to the entire area of the fixing roller 6A in the image adjustment pattern printing mode. This is because the toner on the paper 11 is only for the image adjustment pattern 15 and it is not necessary to fix anything on the paper 11.

  In order to prevent an increase in cost, it is desirable that the transfer voltages 17Y, 17M, 17C, and 17K and the image adjustment pattern removal reverse transfer voltage 17F are applied from the same power source. This is because the transfer voltage and the reverse transfer voltage 17F for image adjustment pattern removal have the same polarity.

  Furthermore, it is also effective to manipulate the transfer voltage in order to reliably remove the image adjustment pattern 15 using the reverse transfer voltage 17F for image adjustment pattern removal.

  Specifically, the transfer voltage for transferring the image adjustment pattern 15 from the photoconductors 4A to 4D to the paper 11 is set lower than the transfer voltage for transferring the image to be printed by the user. Thereby, the image adjustment pattern 15 is easily removed by the transfer roller 6A.

  [Effects of the embodiment]

  According to the above-described embodiment, after the mark (resist pattern) is transferred onto the sheet, the mark can be detected between the transfer process and the fixing process. The mark is removed from the sheet by the fixing unit. By installing a registration control function that automatically prevents color misregistration in the device, users can save time and effort.

  Further, since the resist pattern is automatically removed, it is possible to prevent wasteful consumption of paper. Furthermore, since it is not necessary to have a special apparatus for removing the resist pattern, the machine can be miniaturized. This can contribute to cost reduction of the image forming apparatus.

  [Others]

  The processing in the above-described embodiment may be performed by software or by using a hardware circuit.

  In addition, a program for executing the processing in the above-described embodiment can be provided, and the program is recorded on a recording medium such as a CD-ROM, a flexible disk, a hard disk, a ROM, a RAM, and a memory card and provided to the user. You may decide to do it. The program may be downloaded to the apparatus via a communication line such as the Internet.

  In addition, it should be thought that the said embodiment is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a diagram illustrating a hardware configuration of an image forming apparatus according to a first embodiment. FIG. 2 is a diagram showing a configuration for performing registration control included in the image forming apparatus of FIG. 1. FIG. 3 is a view of a part of the configuration of FIG. 2 viewed from the fixing roller 6A side. FIG. 6 is a graph showing a relationship between a fixing temperature and a fixing ratio. It is a figure which shows the specific example of an image adjustment pattern. FIG. 6 is a diagram of a part of a configuration for performing registration control in an image forming apparatus provided with an image adjustment pattern printing mode as viewed from the fixing roller 6A side. 10 is a flowchart illustrating a fixing roller temperature control process according to a mode according to the second embodiment. It is a figure which shows the structure of the image forming apparatus in 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Paper feed cassette 3 Paper feed part 4 Photoconductor 4A Y color photoconductor 4B M color photoconductor 4C C color photoconductor 4D K color photoconductor 5 Transfer part 5A Y color transfer roller (transfer part)
5B M color transfer roller (transfer section)
5C C color transfer roller (transfer section)
5D K color transfer roller (transfer section)
DESCRIPTION OF SYMBOLS 6 Fixing part 6A Fixing roller 6B Fixing pressure roller 6C Fixing cleaning roller 7 Paper discharge part 11 Paper 11A User print area 12 Toner 12A Unfixed toner 12B Fixing toner 14, 14A, 14B Image adjustment pattern reading sensor 15 Image adjustment pattern 16A, 16B Image adjustment pattern removal unit 17Y Y transfer voltage 17M M transfer voltage 17C C transfer voltage 17K K transfer voltage 17F Image adjustment pattern removal reverse transfer voltage 51 Controller

Claims (12)

Forming means for forming a pattern for image adjustment on a recording medium;
Detecting means for detecting a pattern for image adjustment formed by the forming means;
An image forming apparatus comprising: a fixing unit having a function of fixing an image on a recording medium; and a function of removing the image adjustment pattern from the recording medium. The forming unit includes a plurality of image forming units corresponding to a plurality of colors,
The image forming apparatus according to claim 1, further comprising a control unit that controls a plurality of image forming units corresponding to each of the plurality of colors based on a detection result of the detection unit. The plurality of image forming units corresponding to each of the plurality of colors are arranged side by side,
The image forming apparatus according to claim 2, wherein a color image is formed by sequentially transferring a toner image of each color while conveying a sheet as a recording medium to the plurality of image forming units.   The image forming apparatus according to claim 1, wherein the detection unit is provided between the forming unit and the fixing unit.   The image forming apparatus according to claim 1, wherein the image adjustment pattern is formed on the same recording medium as the recording medium on which an image is printed.   The image forming apparatus according to claim 1, wherein the image adjustment pattern is formed at an end portion of a recording medium on which an image is printed and outside a user print area. A setting unit for setting a mode for forming a pattern for image adjustment;
The image forming apparatus according to claim 1, wherein an image adjustment pattern is formed on a recording medium and removed by the fixing unit in a mode for forming the image adjustment pattern.   The image forming apparatus according to claim 1, wherein the fixing unit removes the image adjustment pattern from the recording medium by a low temperature offset or a high temperature offset for fixing.   The image forming apparatus according to claim 1, wherein the fixing unit removes the image adjustment pattern from the recording medium by applying a reverse transfer voltage.   The image forming apparatus according to claim 1, wherein the image adjustment pattern is a pattern in which a leading end, a rear end, or both of the pattern is sharpened. A forming step of forming a pattern for image adjustment on a recording medium;
A detection step of detecting a pattern for image adjustment formed by the forming means;
Image forming comprising: a step of removing the image adjustment pattern from the recording medium by a fixing unit having a function of fixing the image on the recording medium and a function of removing the image adjustment pattern from the recording medium. Control method of the device. A forming step of forming a pattern for image adjustment on a recording medium;
A detection step of detecting a pattern for image adjustment formed by the forming means;
Causing the computer to execute a step of removing the image adjustment pattern from the recording medium by a fixing unit having a function of fixing the image on the recording medium and a function of removing the image adjustment pattern from the recording medium. A control program for an image forming apparatus.

Images