JP5819623B2 - Color image forming apparatus - Google Patents

Description

  The present invention relates to a color image forming apparatus that corrects a printing deviation by determining a printing deviation amount on the apparatus side.

  The color image forming apparatus reproduces a target color by superimposing and printing four colors of cyan, magenta, yellow, and black. For this reason, if any one of cyan, magenta, yellow, and black causes a printing shift, the color image forming apparatus cannot reproduce the target color.

  Conventionally, as a color image forming apparatus that determines the amount of printing deviation on the apparatus side and corrects printing deviation, a printing unit prints a pattern on a sheet based on the pattern data stored in the storage unit, and is printed on the sheet. The pattern is optically read by the reading unit, the printing deviation amount is calculated by the deviation amount calculation unit based on the pattern read by the reading unit, and the printing deviation is calculated by the correction unit based on the printing deviation amount calculated by the deviation amount calculation unit. A color image forming apparatus that corrects the above is known (for example, see Patent Document 1).

JP 2006-71737 A

  When the color image forming apparatus includes an intermediate transfer belt, the thickness of the intermediate transfer belt may be uneven due to wear or the like as the number of printed sheets of the color image forming apparatus increases. When unevenness occurs in the thickness of the intermediate transfer belt, different printing deviations occur depending on the location of the intermediate transfer belt. For this reason, in order to correct with sufficient accuracy the printing deviation that occurs when the thickness of the intermediate transfer belt is uneven, it is necessary to determine the printing deviation amount for one rotation of the intermediate transfer belt. However, in the conventional color image forming apparatus, when the distance of one cycle of the intermediate transfer belt is longer than the distance in the conveyance direction of one sheet, even if a pattern is printed on one sheet, the intermediate transfer belt Since it is not possible to determine the amount of printing deviation for one round, it is not possible to correct the printing deviation that occurs when the thickness of the intermediate transfer belt is uneven with sufficient accuracy.

  SUMMARY An advantage of some aspects of the invention is that it provides a color image forming apparatus capable of correcting a printing misalignment that occurs when the thickness of the intermediate transfer belt is uneven with higher accuracy than in the past.

  A color image forming apparatus according to the present invention includes a printer including an intermediate transfer belt to which images of a plurality of colors are transferred, and a pattern printing unit that prints a correction pattern for printing deviation on a sheet using the printer. A pattern reading unit that reads the pattern printed on the paper by the pattern printing unit, a print deviation amount determining unit that determines a print deviation amount based on the pattern read by the pattern reading unit, and the print deviation amount A printing deviation correction unit that corrects a printing deviation according to a printing deviation amount determined by the determination unit; and a number storage unit that stores the number of prints of the printer. The pattern printing unit includes the number storage unit. The pattern is printed on a number of sheets corresponding to the number of prints stored in step (1).

  With this configuration, the color image forming apparatus of the present invention can print a pattern on a plurality of sheets of paper, and thus corrects a print deviation that occurs when the thickness of the intermediate transfer belt is uneven with higher accuracy than before. can do. In addition, since the color image forming apparatus of the present invention prints a pattern on the number of sheets corresponding to the number of printed sheets of the printer, it is possible to correct the printing deviation with appropriate accuracy.

  In addition, the color image forming apparatus of the present invention includes a correction control unit that controls correction of print misalignment, and a correction method accepting unit that accepts selection of a print misalignment correction method by a user, the correction method accepting unit. Is a correction method in which the pattern printing unit prints the pattern on a predetermined number of sheets, and the pattern printing unit prints the pattern on a number of sheets corresponding to the number of printed sheets stored in the number storing unit. At least a correction method and a correction method in which the pattern printing unit prints the pattern on a sheet of paper are received, and the correction control unit corrects printing deviation according to the correction method received by the correction method reception unit. May be controlled.

  With this configuration, the color image forming apparatus of the present invention can perform correction of printing misalignment with accuracy required by the user.

  In addition, the pattern reading unit of the color image forming apparatus of the present invention may be a scanner that reads an image from a sheet placed by a user.

  With this configuration, the color image forming apparatus according to the present invention can be realized without a dedicated device for reading a pattern printed on a sheet as long as it has a scanner for reading an image from a sheet placed by a user. Can be done.

  Further, the pattern of the color image forming apparatus of the present invention is an image in which a plurality of colors are superimposed on the same figure, and is an image for allowing a user to visually confirm the occurrence of a print error. A visual recognition mark may be included.

  With this configuration, the color image forming apparatus of the present invention can allow the user to determine whether or not the paper on which the pattern is printed is read by the scanner based on the print misalignment visual recognition mark.

  The color image forming apparatus of the present invention can correct a printing misalignment that occurs when unevenness occurs in the thickness of the intermediate transfer belt with higher accuracy than before.

1 is a schematic configuration diagram of an MFP according to an embodiment of the present invention. FIG. 2 is a block diagram of the MFP shown in FIG. 1. It is a figure which shows the pattern printed by the pattern printing means shown in FIG. FIG. 3 is a diagram showing a screen displayed on the display shown in FIG. 2 when the printer is in a printable state. FIG. 3 is a flowchart of a process for correcting misalignment by a controller shown in FIG. It is a figure which shows the correction method selection screen displayed on the display shown in FIG. It is a flowchart of the simple correction process shown in FIG. (A) It is a figure which shows the printing instruction | indication reception screen displayed on the display shown in FIG. 2 in a simple correction process. (B) It is a figure which shows the reading instruction | indication reception screen displayed on the display shown in FIG. FIG. 4 is an enlarged view of a print misalignment visual recognition mark shown in FIG. 3 when a print misalignment occurs. It is a flowchart of the standard correction process shown in FIG. It is a figure which shows the printing instruction | indication reception screen displayed on the display shown in FIG. 2 in a standard correction process. It is a flowchart of the detailed correction process shown in FIG. It is a figure which shows the printing instruction | indication reception screen displayed on the display shown in FIG. 2 in a detailed correction process. It is a schematic block diagram of the printer dedicated machine which concerns on other embodiment of this invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  First, the configuration of the color image forming apparatus according to the present embodiment will be described.

  FIG. 1 is a schematic configuration diagram of an MFP (Multifunction Peripheral) 10 as a color image forming apparatus according to the present embodiment.

  As illustrated in FIG. 1, the MFP 10 includes a printer 20 that performs printing on a sheet 91 and a scanner 30 that reads an image from the sheet 91 placed by a user.

  The printer 20 includes a paper feed cassette 21 for storing A4 size paper 91, a photosensitive drum 22a for forming a cyan image, a photosensitive drum 22b for forming a magenta image, and a photosensitive body for forming a yellow image. A drum 22c, a photosensitive drum 22d for forming a black image, a cyan image formed on the photosensitive drum 22a, a magenta image formed on the photosensitive drum 22b, and a yellow image formed on the photosensitive drum 22c. An intermediate transfer belt 23 on which the image and the black image formed on the photosensitive drum 22d are superimposed and transferred, a transfer unit 24 that transfers the image transferred on the intermediate transfer belt 23 to a sheet, and the image transferred to the sheet The fixing unit 25 that fixes the image onto the paper, the paper discharge unit 26 that discharges the paper, and the paper from the paper cassette 21 to the paper discharge unit 26 And a conveying unit (not shown) to feed. The transport unit transports the sheet 91 in the short side direction of the sheet 91.

  The distance of one turn of the intermediate transfer belt 23 is longer than three times the distance in the conveyance direction of one sheet 91 and is not more than four times the distance in the conveyance direction of one sheet 91.

  FIG. 2 is a block diagram of the MFP 10.

  As shown in FIG. 2, the MFP 10 is connected to the printer 20 and the scanner 30 and controls the entire MFP 10, the display 51 connected to the controller 40 and displaying various information, and connected to the controller 40. Network communication via a LAN (Local Area Network) and an external device (not shown) such as a PC (Personal Computer) that is connected to the controller 40, and an operation unit 52 in which various operations are input by a user. And a storage unit 54 such as an EEPROM (Electrically Erasable Programmable Read Only Memory) connected to the controller 40. And.

  The controller 40 includes a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores programs and various data in advance, and a RAM (Rewriteable Volatile Storage Device used as a work area of the CPU). Random Access Memory). The CPU is an arithmetic processing unit that operates the controller 40 by executing a program stored in the ROM. The RAM temporarily stores programs and various data when the programs are executed by the CPU.

  The controller 40 executes a program stored in the ROM so as to control a correction control unit 41 that controls correction of print misalignment, a correction method accepting unit 42 that accepts selection of a correction method of print misalignment by a user, and the printer 20. A pattern printing unit 43 that prints a pattern for correcting a printing deviation on the paper 91, a printing deviation amount judging unit 44 that judges a printing deviation amount based on the pattern read by the scanner 30, and a printing deviation amount determination. It functions as a print misalignment correction means 45 that corrects the print misalignment according to the print misalignment amount determined by the means 44.

  The scanner 30 reads the pattern printed on the paper 91 by the pattern printing unit 43, and constitutes the pattern reading unit of the present invention.

  The display 51 is a display device such as an LCD (Liquid Crystal Display).

  The operation unit 52 is an input device such as a button that forms a touch panel together with the display 51.

  For example, the network interface 53 receives print data to be printed by the printer 20 from an external device via a LAN, and transmits image data generated by the scanner 30 to an external device via the LAN.

  The storage unit 54 is configured to store the number of printed sheets of the printer 20 and constitutes a number storage unit of the present invention.

  FIG. 3 is a diagram showing a pattern printed by the pattern printing unit 43.

  As shown in FIG. 3, the pattern 60 is near the beginning of the sheet 91 in the sub-scanning direction indicated by the arrow 91a, which is the conveyance direction of the sheet 91 by the printer 20, and is orthogonal to the sub-scanning direction indicated by the arrow 91a. A reference position mark 61, which is an image indicating a reference position, is drawn in black only near one end of the sheet 91 in the main scanning direction indicated by an arrow 91b. Further, in the pattern 60, a square 60a drawn only in cyan, a square 60b drawn only in magenta, a square 60c drawn only in yellow, and a square 60d drawn only in black are indicated by arrows 91a. The main-scanning-direction print deviation amount determination mark 62, which is an image arranged one by one in the scanning direction and is an image for determining the amount of printing deviation in the main-scanning direction, is a sheet in the sub-scanning direction indicated by an arrow 91a. In the vicinity of the top of 91, a plurality are arranged in the main scanning direction indicated by arrow 91b. The pattern 60 is an image in which a square 60a, a square 60b, a square 60c, and a square 60d are arranged one by one in the main scanning direction indicated by an arrow 91b, and is used for determining the amount of printing deviation in the sub-scanning direction. A plurality of sub-scanning direction print misregistration determination marks 63, which are images, are arranged in the sub-scanning direction indicated by an arrow 91a near both ends of the sheet 91 in the main scanning direction indicated by an arrow 91b. Further, the pattern 60 is an image in which cyan, magenta, yellow, and black are superimposed on the same square, and is a print misalignment visual recognition mark 64 that is an image for allowing the user to visually confirm the occurrence of the print misalignment. Are arranged between the main scanning direction printing deviation amount determination marks 62 or between the sub scanning direction printing deviation amount determination marks 63. The square 60a, square 60b, square 60c, and square 60d are drawn in different patterns in FIG. 3, but are actually filled with cyan, magenta, yellow, and black, respectively.

  Next, the operation of the MFP 10 will be described.

  FIG. 4 is a diagram illustrating a screen displayed on the display 51 when the printer 20 is in a printable state.

  The controller 40 displays the screen shown in FIG. 4 on the display 51 when the printer 20 is in a printable state. The screen shown in FIG. 4 includes a “copy” button 71 a for accepting from the user a “copy” instruction to print an image read from the document by the scanner 30 with the printer 20, and “print deviation correction” for correcting the print deviation. "Print misalignment correction" button 71b for receiving an instruction "" from the user.

  FIG. 5 is a flowchart of the process for correcting the printing deviation by the controller 40.

  When the screen shown in FIG. 4 is displayed on the display 51 and the “print deviation correction” button 71b is pressed by the user via the operation unit 52, the controller 40 starts the process shown in FIG.

  As shown in FIG. 5, the correction control means 41 of the controller 40 displays the correction method selection screen shown in FIG. 6 on the display 51 by the correction method receiving means 42 (S101).

  The correction method selection screen shown in FIG. 6 includes a “simple correction” button 72a for accepting an instruction of “simple correction” which is a correction method in which the pattern printing unit 43 prints the pattern 60 on one sheet of paper. The “standard correction” button 72b for accepting an instruction of “standard correction”, which is a correction method for the pattern printing means 43 to print the pattern 60 on the number of sheets corresponding to the number of prints stored in the storage unit 54, from the user. And a “detailed correction” button 72c for accepting an instruction of “detailed correction”, which is a correction method in which the pattern printing unit 43 prints the pattern 60 on the four sheets 91, from the user.

  As illustrated in FIG. 5, the correction control unit 41 performs the printing deviation correction method by the user until it is determined that the correction method reception unit 42 has received selection of the printing deviation correction method by the user after the process of S101. It is determined whether or not the selection is accepted (S102). Here, the correction method accepting means 42 allows the user to press the “simple correction” button 72 a, “standard correction” button 72 b, or “detailed correction” button 72 c by the user via the operation unit 52. Accepts selection of correction method for print misalignment.

  If it is determined in S102 that the user has received selection of a correction method for print misalignment, the correction control unit 41 selects any one of “simple correction”, “standard correction”, and “detailed correction” as the correction method receiving unit 42. (S103). Here, when the “simple correction” button 72 a is pressed by the user via the operation unit 52, the correction method accepting unit 42 accepts “simple correction” as the correction method for the printing deviation selected by the user, When the “standard correction” button 72 b is pressed by the user via the operation unit 52, “standard correction” is accepted as the correction method for the printing deviation selected by the user, and the “detailed correction” button 72 c is displayed on the operation unit 52. When it is pressed by the user via “”, “detailed correction” is accepted as the correction method of the printing deviation selected by the user.

  If it is determined in S103 that “simple correction” has been accepted, the correction control means 41 executes a “simple correction process” to be described later (S104), and ends the process shown in FIG.

  If it is determined in S103 that “standard correction” has been accepted, the correction control means 41 executes “standard correction processing” described later (S105), and ends the processing shown in FIG.

  If it is determined in S103 that “detailed correction” has been accepted, the correction control means 41 executes “detailed correction processing” described later (S106), and ends the processing shown in FIG.

  FIG. 7 is a flowchart of the simple correction process shown in FIG.

  As shown in FIG. 7, the correction control means 41 displays a print instruction acceptance screen shown in FIG. 8A on the display 51 (S121).

  In the print instruction acceptance screen shown in FIG. 8A, a message 73a for prompting the user to set one or more sheets 91 in the paper cassette 21 and an instruction to print the pattern 60 are accepted from the user. The print button 73b is included.

  As shown in FIG. 7, after the process of S121, the correction control means 41 determines whether or not the print button 73b has been pressed until it is determined that the print button 73b has been pressed (S122).

  If it is determined in S122 that the print button 73b has been pressed, the correction control means 41 controls the pattern printing means 43 to print the pattern 60 on the paper 91 (S123).

  Next, the correction control means 41 determines whether or not a “paper out error”, which is an error that cannot be printed because there is no paper 91 in the paper feed cassette 21, has occurred (S124).

  If it is determined in S124 that a “paper out error” has occurred, the correction control means 41 displays on the display 51 that a “paper out error” has occurred (S125), and returns to the processing of S121.

  On the other hand, if it is determined in S124 that the “paper out error” has not occurred, the correction control means 41 displays a read instruction acceptance screen shown in FIG. 8B on the display 51 (S126).

  In the reading instruction reception screen shown in FIG. 8B, a message 74a that prompts the user to set the paper 91 on which the pattern 60 is printed on the scanner 30, and an instruction to read the paper 91 on which the pattern 60 is printed. Is read from the user, and a read end button 74c is received for receiving an instruction to end reading of the sheet 91 on which the pattern 60 is printed.

  FIG. 9 is an enlarged view of the print misalignment visual recognition mark 64 of the pattern 60 when the print misalignment occurs.

  As shown in FIG. 9, when there is a print misalignment, the print misalignment visual recognition marks 64 of the pattern 60 printed on the paper 91 are a square 60a drawn only in cyan and a square 60b drawn only in magenta. At least one of the square 60c drawn only in yellow and the square 60d drawn only in black is shifted from the other. When the user can visually confirm that at least one print misalignment visual recognition mark 64 of the pattern 60 printed on the sheet 91 has a shape different from the schedule, for example, a distorted shape, the scanner 30 is used for the sheet 91. Need to be loaded. Conversely, when the user can visually confirm that all the print misalignment marks 64 of the pattern 60 printed on the paper 91 are clean squares as planned, the paper 91 is read into the scanner 30. There is no need to let Therefore, when the user can visually confirm that all the print misalignment marks 64 of the pattern 60 are clean squares, the user may press the reading end button 74c. The square 60a, square 60b, square 60c, and square 60d are drawn in different patterns in FIG. 9, but are actually filled with cyan, magenta, yellow, and black, respectively.

  As shown in FIG. 7, the correction control means 41 determines whether or not the read button 74b has been pressed after the processing of S126 (S127).

  If it is determined in S127 that the read button 74b has not been pressed, the correction control means 41 determines whether or not the read end button 74c has been pressed (S128).

  If it is determined in S128 that the read end button 74c has not been pressed, the correction control means 41 returns to the process of S127.

  On the other hand, if it is determined in S128 that the read end button 74c has been pressed, the correction control means 41 ends the process shown in FIG.

  If it is determined that the read button 74b is pressed in S127, the correction control means 41 reads the pattern 60 from the paper 91 by the scanner 30 (S129).

  Next, the correction control means 41 determines whether or not the position of the reference position mark 61 indicating the reference position in the pattern 60 is within an allowable range (S130). Here, the allowable range is a range in which the correction control unit 41 can correct the position of the pattern 60 read from the paper 91 by the scanner 30 to an appropriate position in the process.

  If it is determined in S130 that it is not within the allowable range, the correction control means 41 displays a message on the display 51 prompting the user to correctly set the paper 91 on which the pattern 60 is printed on the scanner 30 (S131). The process returns to S126.

  If it is determined in S130 that it is within the allowable range, the correction control means 41 causes the print deviation amount determination means 44 to determine the print deviation amount (S132). Here, the print misregistration amount determination means 44 uses the square 60a drawn only in black and magenta as the reference for the square 60d drawn only in black for each main scanning direction print misregistration determination mark 62 of the pattern 60. A position in the main scanning direction indicated by an arrow 91b of a square 60b drawn only with a square and a square 60c drawn only with yellow is obtained. The position obtained in this way is the print misalignment amount in the main scanning direction indicated by cyan, magenta, and yellow arrows 91b, respectively. Note that the print misalignment amount in the main scanning direction indicated by the arrows 91b for cyan, magenta, and yellow is finally obtained by averaging the print misalignment amounts for all the main scan direction print misalignment determination marks 62 of the pattern 60. Desired. Similarly, the print misregistration amount determination means 44 uses a square 60a drawn only in black and magenta for each sub-scanning direction print misregistration determination mark 63 of the pattern 60 with reference to a square 60d drawn only in black. The position in the sub-scanning direction indicated by the arrow 91a of the square 60b drawn only by the square and the square 60c drawn only by the yellow is obtained. The position obtained in this way is the amount of print misalignment in the sub-scanning direction indicated by cyan, magenta, and yellow arrows 91a, respectively. Note that the print misalignment amounts in the sub-scanning direction indicated by the arrows 91a for cyan, magenta, and yellow are finally obtained by averaging the print misalignment amounts for all the sub-scan direction print misalignment determination marks 63 of the pattern 60. Desired.

  Next, the correction control means 41 causes the printing deviation correction means 45 to correct the printing deviation according to the printing deviation amount determined by the printing deviation amount judgment means 44 in S132 (S133). Here, the print misalignment correcting means 45 determines the positions of the images formed on the photosensitive drum 22a, the photosensitive drum 22b, and the photosensitive drum 22c for cyan, magenta, and yellow, respectively, in the print misalignment determining means 44 in S132. A correction value to be changed according to the printing deviation amount is calculated, and the calculated correction value is stored in the storage unit 54. Therefore, the controller 40 thereafter forms cyan, magenta, and yellow images at positions on the photosensitive drum 22a, the photosensitive drum 22b, and the photosensitive drum 22c, respectively, corrected with the correction values stored in the storage unit 54. By doing so, printing deviation can be reduced.

  The correction control means 41 ends the process shown in FIG. 7 after the process of S133.

  FIG. 10 is a flowchart of the standard correction process shown in FIG.

  As shown in FIG. 10, the correction control means 41 obtains the number N of sheets 91 on which the pattern 60 is printed according to the number of prints stored in the storage unit 54 (S141). Here, as described above, the distance for one turn of the intermediate transfer belt 23 is longer than three times the distance in the conveyance direction of one sheet 91 and four times the distance in the conveyance direction of one sheet 91. It is as follows. That is, the printing deviation amount for one rotation of the intermediate transfer belt 23 can be determined by the four sheets 91. Accordingly, the minimum number N is 1 and the maximum is 4, and is set so as to increase stepwise in accordance with the number of printed sheets stored in the storage unit 54. For example, the number N is 1 when the number of printed sheets is less than 100, 2 when the number of printed sheets is 100 or more and less than 200, and the number of printed sheets is 200 or more and less than 300. 3 and 4 when the number of printed sheets is 300 or more.

  Next, the correction control means 41 displays the print instruction acceptance screen shown in FIG. 11 on the display 51 (S142).

  The print instruction acceptance screen shown in FIG. 11 includes a message 75a that prompts the user to set N or more sheets 91 in the paper feed cassette 21, and a print button for accepting an instruction to print the pattern 60 from the user. 75b. It should be noted that the numerical value from 1 to 4 obtained in S141 is actually substituted for N in the message 75a.

  As shown in FIG. 10, after the process of S142, the correction control means 41 determines whether or not the print button 75b has been pressed until it is determined that the print button 75b has been pressed (S143).

  If it is determined that the print button 75b is pressed in S143, the correction control means 41 sets the counter value on the RAM to 0 (S144).

  Next, the correction control means 41 controls the pattern printing means 43 to print the pattern 60 on the paper 91 (S145), and increments the counter value on the RAM by 1 (S146).

  Next, the correction control means 41 determines whether or not a “paper out error” has occurred (S147).

  If it is determined in S147 that a “paper out error” has occurred, the correction control means 41 displays on the display 51 that a “paper out error” has occurred (S148), and the process returns to S142.

  On the other hand, if it is determined in S147 that the “paper out error” has not occurred, the correction control means 41 determines whether or not the counter value on the RAM has reached N determined in S141 (S149).

  If it is determined in S149 that N has not been reached, the correction control means 41 returns to the process of S145.

  On the other hand, if it is determined in S149 that N, the correction control means 41 sets the counter value on the RAM to 0 (S150).

  Next, the correction control means 41 displays a read instruction reception screen shown in FIG. 8B on the display 51 (S151).

  Next, the correction control means 41 determines whether or not the read button 74b has been pressed (S152).

  If it is determined in S152 that the read button 74b has not been pressed, the correction control means 41 determines whether or not the read end button 74c has been pressed (S153).

  It should be noted that the user scans only the paper 91 other than the paper 91 that can visually confirm that all the print misalignment marks 64 of the pattern 60 are clean squares among the paper 91 on which the pattern 60 is printed. After reading, the reading end button 74c may be pressed.

  If it is determined in S153 that the read end button 74c has not been pressed, the correction control means 41 returns to the process of S152.

  If it is determined that the read button 74b is pressed in S152, the correction control means 41 reads the pattern 60 from the paper 91 by the scanner 30 (S154).

  Next, the correction control means 41 determines whether or not the position of the reference position mark 61 indicating the reference position in the pattern 60 is within the allowable range (S155).

  If it is determined in S155 that it is not within the allowable range, the correction control means 41 displays a message on the display 51 prompting the user to correctly set the paper 91 on which the pattern 60 is printed on the scanner 30 (S156). The process returns to S151.

  If it is determined in S155 that the value is within the allowable range, the correction control unit 41 increments the counter value on the RAM by 1 (S157), and determines whether or not the counter value on the RAM has reached N obtained in S141. Judgment is made (S158).

  If it is determined in S158 that the value is not N, the correction control means 41 returns to the process of S151.

  On the other hand, if it is determined that the answer is N in S158, the correction control unit 41 causes the print deviation amount determination unit 44 to determine the print deviation amount (S159). Note that the print deviation amounts in the main scanning direction indicated by the arrows 91b for cyan, magenta, and yellow are all marks for determining the print deviation amounts in all main scanning directions of the patterns 60 of all the sheets 91 read by the scanner 30. The amount of printing deviation for 62 is obtained by averaging. Further, the print misalignment amounts in the sub-scanning direction indicated by the arrows 91a for cyan, magenta, and yellow are all marks for determining the print misalignment amounts in all sub-scanning directions of the patterns 60 of all the sheets 91 read by the scanner 30. The print deviation amount for 63 is obtained by averaging.

  Next, the correction control means 41 causes the printing deviation correction means 45 to correct the printing deviation according to the printing deviation amount determined by the printing deviation amount judgment means 44 in S159 (S160).

  If it is determined in S153 that the reading end button 74c has been pressed, the correction control means 41 executes S159 and S160. Here, when there is no sheet 91 on which the pattern 60 has been read by the scanner 30, the correction control unit 41 does not substantially correct the printing deviation in S160.

  The correction control means 41 ends the process shown in FIG. 10 after the process of S160.

  FIG. 12 is a flowchart of the detailed correction process shown in FIG.

  As shown in FIG. 12, the correction control means 41 displays the print instruction acceptance screen shown in FIG. 13 on the display 51 (S171).

  The print instruction acceptance screen shown in FIG. 13 includes a message 76a that prompts the user to set four or more sheets 91 in the paper feed cassette 21, and a print button for accepting an instruction to print the pattern 60 from the user. 76b.

  As shown in FIG. 12, the correction control means 41 executes the processes of S172 to S189 after the process of S171 and ends the process shown in FIG. Note that the processing of S172 to S189 is the same as the processing of S143 to S160 except that the number N is replaced with 4 in the processing of S143 to S160 of the standard correction processing, and thus detailed description thereof is omitted.

  As described above, since the MFP 10 can print the pattern 60 on a plurality of sheets 91 (S145 to S149 and S174 to S178), it occurs when the thickness of the intermediate transfer belt 23 is uneven. Printing deviation can be corrected with higher accuracy than before.

  Since the MFP 10 prints the pattern 60 on the number of sheets 91 corresponding to the number of sheets printed by the printer 20 (S141, S145 to S149), it is possible to correct the printing misalignment with appropriate accuracy. Therefore, the MFP 10 can appropriately suppress the consumption amount of the sheet 91 on which the pattern 60 is printed at the time of correcting the printing deviation. Further, since the MFP 10 can appropriately suppress the number of sheets 91 on which the pattern 60 is printed, it is possible to appropriately suppress the user's trouble when reading the sheet 91 on which the pattern 60 is printed by the scanner 30. it can.

  The MFP 10 controls the correction of the printing misalignment according to the correction method received by the correction method accepting unit 42 (S103 to S106), so that the MFP 10 performs the correction of the printing misalignment with the accuracy required by the user. be able to. For example, the user can reduce the consumption of the sheet 91 on which the pattern 60 is printed, or the pattern 60 has been printed, as compared with the case where the correction of the print deviation is highly accurate. When emphasizing the effort to read the paper 91 with the scanner 30, “simple correction” that minimizes the number of sheets 91 on which the pattern 60 is printed can be selected as a method for correcting the printing deviation. Conversely, the user can reduce the consumption of the sheet 91 on which the pattern 60 is printed when correcting the printing misalignment, and can reduce the trouble of reading the sheet 91 on which the pattern 60 is printed by the scanner 30. Compared with the above, when emphasizing that the correction of printing deviation is highly accurate, “detailed correction” in which the number of sheets 91 on which the pattern 60 is printed is the maximum can be selected as a printing deviation correction method. . Further, when the user desires to correct the printing misalignment with the accuracy corresponding to the number of prints of the printer 20, the pattern 60 is printed on the sheet 91 of the number corresponding to the number of prints of the printer 20. "Can be selected as a correction method for print misalignment.

  The MFP 10 includes the print misalignment visual recognition mark 64, which is an image in which a plurality of colors are superimposed on the same figure, in the pattern 60. Therefore, whether or not the MFP 30 reads the paper 91 on which the pattern 60 is printed is read. Can be determined by the user based on the print misalignment visual recognition mark 64 in the pattern 60. Accordingly, the MFP 10 can appropriately suppress the number of sheets 91 to be read by the scanner 30 among the sheets 91 on which the pattern 60 is printed. That is, the MFP 10 can appropriately reduce the user's trouble when reading the sheet 91 on which the pattern 60 is printed by the scanner 30.

  Note that the number of marks for visually confirming print misregistration 64 included in the pattern 60 may be other than the number shown in the present embodiment. Similarly, the position of the print misalignment visual recognition mark 64 in the pattern 60 may be a position other than the position shown in the present embodiment.

  Moreover, the shape of the mark for visually confirming printing deviation 64 may be a shape other than the shape shown in the present embodiment. For example, the shape of the mark for visually confirming printing deviation 64 may be a rectangle other than a square, or may be a circle.

  In this embodiment, the MFP 10 reads a plurality of sheets 91 on which the pattern 60 is printed by the scanner 30 one by one (S151 to S158 and S180 to S187). However, when the scanner 30 includes an ADF (Auto Document Feeder), the MFP 10 uses the ADF to read a plurality of sheets 91 on which the pattern 60 is printed by the scanner 30 at a time. Also good.

  In the present embodiment, the MFP 10 determines the amount of printing deviation for one turn of the intermediate transfer belt 23 using four A4 size sheets 91. Here, the number of sheets required to determine the amount of printing deviation for one turn of the intermediate transfer belt 23 is determined according to the distance of one turn of the intermediate transfer belt 23 and the size of the sheet to be used. . For example, when the MFP 10 can select an A3 size paper as the paper on which the pattern 60 is printed, in addition to the A4 size paper, the printing deviation amount for one turn of the intermediate transfer belt 23 is set to 2 for an A3 size paper. It can be determined using a sheet.

  In this embodiment, when printing the pattern 60 on the plurality of sheets 91 in this embodiment, the MFP 10 has already been used when the pattern 60 is printed when a paper out error occurs (YES in S147 and YES in S176). Since the range of the intermediate transfer belt 23 is unknown, the pattern 60 is reprinted from the first sheet 91 (S144 and S173). However, if the MFP 10 can store the range of the intermediate transfer belt 23 that has already been used when the pattern 60 is printed, the range of the intermediate transfer belt 23 that is not yet used when the pattern 60 is printed can be used as the absence of paper. If the pattern 60 is used after an error has occurred, it is not necessary to reprint the pattern 60 from the first sheet 91, and it is only necessary to print the pattern 60 on the remaining number of sheets 91.

  Since the MFP 10 is configured to read the pattern 60 printed on the paper 91 by the pattern printing unit 43 using the scanner 30, if the MFP 10 includes the scanner 30 that reads an image from the paper 91 arranged by the user, the paper 91. Even if it does not have a dedicated device for reading the pattern 60 printed on the printer, it can be realized. In other words, an image forming apparatus that includes a printer having an intermediate transfer belt to which images of a plurality of colors are transferred and a scanner that reads an image from a sheet placed by a user is modified in software to be executed. As a result, it can be realized as a color image forming apparatus of the present invention.

  The color image forming apparatus of the present invention is an MFP in the present embodiment, but may be a color image forming apparatus other than the MFP, such as a copier.

  For example, the color image forming apparatus of the present invention may be a printer dedicated machine 80 as shown in FIG.

  FIG. 14 is a schematic configuration diagram of the printer dedicated machine 80.

  As shown in FIG. 14, the printer-dedicated device 80 does not include the scanner 30 (see FIG. 1) that reads an image from a sheet 91 placed by the user. The printer dedicated machine 80 includes an image sensor 81 downstream of the fixing unit 25 on the conveyance path of the paper 91 as a pattern reading means for reading the pattern 60 printed on the paper 91 by the pattern printing means 43 instead of the scanner 30. ing.

  Since the printer dedicated machine 80 includes the image sensor 81 downstream of the fixing unit 25 on the conveyance path of the paper 91, it is not necessary for the user to set the paper 91 on which the pattern 60 is printed on the scanner 30. The printing of the pattern 60 on the paper 91 and the reading of the pattern 60 printed on the paper 91 can be automatically performed by a series of operations.

  14 shows a printer-dedicated machine, but a color image forming apparatus provided with an image sensor 81 downstream from the fixing unit 25 on the conveyance path of the paper 91 is not a printer-dedicated machine such as an MFP. The color image forming apparatus may be used.

10 MFP (color image forming device)
20 Printer 23 Intermediate transfer belt 30 Scanner (pattern reading means)
41 Correction Control Unit 42 Correction Method Accepting Unit 43 Pattern Printing Unit 44 Printing Deviation Amount Determination Unit 45 Printing Deviation Correction Unit 54 Storage Unit (Number of Memory Storage Unit)
60 Patterns 64 Marks for visually confirming misregistration 80 Printer dedicated machine (color image forming device)
81 Image sensor (pattern reading means)
91 paper

Claims (4)

A printer having an intermediate transfer belt to which images of a plurality of colors are transferred, a pattern printing unit that prints a pattern for correcting printing misalignment on the paper using the printer, and printing on the paper by the pattern printing unit A pattern reading unit that reads the pattern that has been read, a print deviation amount determination unit that determines a print deviation amount based on the pattern read by the pattern reading unit, and a print deviation amount that is determined by the print deviation amount determination unit Print deviation correction means for correcting the print deviation according to the number of sheets, and a sheet number storage means for storing the number of printed sheets of the printer counted from when the intermediate transfer belt is new .
The pattern printing means prints the pattern on a number of sheets corresponding to the number of printed sheets stored in the number storage means;
Number of sheets to said pattern is printed by the pattern printing means, the more the number of printed sheets stored by the previous SL number storing means becomes larger, so that many number of sheets to said pattern is printed by the pattern printing means The color image forming apparatus is characterized in that the number of prints stored by the number storage means is associated with an upper limit of a number corresponding to the length of one turn of the intermediate transfer belt . A correction control means for controlling correction of print misalignment, and a correction method accepting means for accepting selection of a print misalignment correction method by the user,
The correction method accepting unit includes a correction method in which the pattern printing unit prints the pattern on a predetermined plurality of sheets, and the pattern printing unit has a number of sheets corresponding to the number of printed sheets stored in the number storing unit. Receiving at least a correction method for printing the pattern and a correction method for printing the pattern on a sheet of paper by the pattern printing unit;
The color image forming apparatus according to claim 1, wherein the correction control unit controls correction of printing deviation in accordance with a correction method received by the correction method receiving unit.   The color image forming apparatus according to claim 1, wherein the pattern reading unit is a scanner that reads an image from a sheet placed by a user.   The pattern includes an image in which a plurality of colors are overlapped with the same graphic, and includes a print misalignment visual recognition mark that is an image for allowing a user to visually confirm the occurrence of a print misalignment. The color image forming apparatus according to claim 3.

Images