Image forming apparatus that changes a permissible range of a
Contents
1. a sequence of acquiring the correction value in the automatic correction will be described First when a prede termined execution condition is satisfied registration patterns for positional deviation correction are formed by the respec tive process units 50Y 50M 50C 50K The execution con dition is determined based on an elapsed time period after a previous acquiring process the number of printed pages environmental changes such as temperature and humidity and a remaining amount of toner for example Specifically as shown in FIG 3 the registration pattern 66 includes a mark group which has a mark 66K formed by the process unit 50K a mark 66C formed by the process unit 50C a mark 66M formed by the process unit 50M and a mark 66Y formed by the process unit 50Y which are arranged in a sub scanning direction The registration pattern 66 is formed at a constant interval in the sub scanning direction a moving direction of the con veyance belt 7 shown in FIG 3 Each ofthe marks 66K 66C US 8 582 993 B2 5 66M 66Y has a rectangular rod shape and is long in a main scanning direction direction perpendicular to the sub scan ning direction Next based on digitized signals output from the mark sensor 61 positions of the respective marks 66K 66Y 66M 66C are detected Then intervals of marks for example marks 66C 66M 66Y of respective adjustment colors rela tive to a mark ofa reference color for example mark 66K i2. wherein the image forming unit is configured to form images of a plurality of colors and wherein the changing unit is configured to determine the permissible range for each of the colors independently 7 The image forming apparatus according to claim 1 wherein the factor includes one of a temperature a humidity and an operation amount of the apparatus 8 An image forming apparatus comprising a manual acquiring unit which is configured to receive an input to acquire a correction value an image forming unit which is configured to form an image while adjusting at least one of positional deviation and density deviation of the image based on the correc tion value a changing unit which is configured to execute at least one of a first changing process of changing a permissible range of a correction value for positional deviation according to a status of a factor causing a change in a position of an image and a second changing process of changing a permissible range of a correction value for density deviation according to a status of a factor caus ing a change in a density of an image and a limiting unit which is configured to limit an input range of the correction value by the manual acquiring unit based on the permissible range 9 The image forming apparatus according to claim 8 wherein the image forming unit is configured to print on a recording sheet a pattern image to be referred to when the input is received by the manual a
3. 31 con trols the respective constitutional elements of the MFP 100 for example a turn on timing of an exposure device config uring the image forming unit 10 driving motors of various rollers configuring a conveyance path of a sheet and a moving motor of an image sensor unit configuring the image reading unit 20 through the ASIC 35 while storing results of the processing in the RAM 33 or NVRAM 34 The network interface 36 is connected to a network and enables connection with the other information processing apparatuses The FAX interface 37 is connected to a tele phone line and enables connection with a FAX apparatus of the other party The MFP 100 performs data communication with an external apparatus through the network interface 36 or FAX interface 37 US 8 582 993 B2 3 Configuration of Image Forming Unit Next a configuration of the image forming unit 10 of the MFP 100 will be described with reference to FIG 2 The image forming unit 10 has a process unit 50 that forms a toner image by an electro photographic method and transfers the toner image on a sheet a fixing device 8 that fixes unfixed toner on the sheet a sheet feeding tray 91 that accommodates sheets therein before the image transfer and a sheet discharge tray 92 which receives sheets thereon after the image transfer The image reading unit 20 is arranged above the image form ing unit 10 The image forming unit 10 has an exposure device 53 that illuminates light
4. the statuses of the factors causing a positional deviation of an image S102 Specifi cally the number of printed pages and the temperature in the apparatus are acquired Then a permissible range ofthe manual correction value is calculated based on the data acquired in S102 S103 In this illustrative embodiment an initial value of a permissible range is stored in the ROM 32 In 103 an assumed expan sion amount of positional deviation is calculated based on the data acquired in S102 and adds the assumed expansion amount to the initial value Specifically the MFP 100 has a printed page number lim iting table 341 that stores an assumed expansion amount a permissible range with respect to the number of printed pages which is shown in FIG 6 and a temperature limiting table 342 that stores an assumed expansion amount of a permissible range with respect to the temperature in the appa ratus which is shown in FIG 7 The number of printed pages is typically the number of printed pages from a previ ous update of the manual or automatic correction value Accordingly the number of printed pages from the previous update is reset when the automatic correction value is updated In addition the temperature limiting table 342 defines the assumed expansion amount for each of tempera ture differences between a reference temperature which is a temperature in the apparatus at the time of the previous update and the current temperature in the a
5. there is a false input and again an input ofa correction value is waited Alternatively when a numeri cal value exceeding the permissible range is input the numerical value exceeding the permissible range may be replaced with a value which is most close to the input value but within the permissible range Further it may be prohibited to input a numerical value exceeding the permissible range at a step before an instruction to complete the input of the correction value Automatic Correction Process Next a sequence ofthe automatic acquiring process that is an acquiring process for automatic correction will be described with reference to a flow chart of FIG 9 The auto matic acquiring process is executed by the CPU 31 when an execution condition which is determined for automatic cor rection in advance is satisfied First the automatic correction value and the manual cor rection value are read out from the NVRAM 34 S201 The MFP 100 stores in the ROM 32 an amount of positional deviation before shipment from a factory as an initial amount of deviation The initial amount of deviation is an amount of positional deviation that is inherent to an apparatus measured for each apparatus when manufacturing the apparatus and is stored in the ROM 32 before shipment The initial amount of deviation is set as the initial value of the automatic correction value In other words the automatic correction value is a value having the initial amount of
6. 31 CPU 32 FAX I F NETWORK I F US 8 582 993 B2 U S Patent Nov 12 2013 Sheet 2 of 9 US 8 582 993 B2 FIG 2 U S Patent Nov 12 2013 Sheet3 of9 US 8 582 993 B2 FIG 3 US 8 582 993 B2 Sheet 4 of 9 Nov 12 2013 U S Patent CD N ee fae i d 398 t 6 G 9 9 L L 8 8 BN E Ol H Zi gr Sid cz f 0l p Zl Vr Old U S Patent Nov 12 2013 Sheet 5 of 9 US 8 582 993 B2 FIG 5 MANUAL ACQUIRING PROCESS READ OUT CORRECTION VALUES 101 ACQUIRE DATA OF FACTOR 102 CAUSING CHANGE CALCULATE PERMISSIBLE RANGE 103 ADJUST PERMISSIBLE RANGE 104 PRINT PATTERN IMAGE 105 106 INSTRUCTION TO VONPEGIE INPUT YES 107 ACQUIRE INPUT VALUE CANCEL INSTRUCTION 5108 UPDATE MANUAL CORRECTION VALUE END U S Patent Nov 12 2013 Sheet 6of9 US 8 582 993 B2 FIG 6 341 THE NUMBER ASSUMED EXPANSION OF PRINTED PAGES AMOUNT 1 1000 1001 2000 3001 4000 4001 342 TEMPERATURE ASSUMED EXPANSION DIFFERENCE AMOUNT 1 jai NR NM DNE 11 15 21 25 U S Patent Nov 12 2013 Sheet7of9 US 8 582 993 B2 U S Patent Nov 12 2013 Sheet 8 of 9 US 8 582 993 B2 FIG 9 AUTOMATIC ACQUIRING PROCESS READ OUT CORRECTION VALUES S201 FORM REGISTRATION PATTERN 202 DETECT REGISTRATION PATTERN 203 CALCULATE AMOUNT OF DE
7. 91966 A 4 2008 JP 2008 134417 A 6 2008 JP 2010 079125 A 4 2010 OTHER PUBLICATIONS Japan Patent Office Notification of Reasons for Refusal for Japanese Patent Application No 2010 146582 counterpart to above cap tioned patent application mailed Jul 9 2013 Japan Patent Office Decision on Rejection for Japanese Patent Appli cation No 2010 146582 counterpart to above captioned patent application mailed Sep 10 2013 cited by examiner Primary Examiner Sophia S Chen 74 Attorney Agent or Firm Baker Botts L L P 57 ABSTRACT An image forming apparatus is provided The image forming apparatus includes a manual acquiring unit which is config ured to receive a user input to acquire a correction value an image forming unit which is configured to form an image while adjusting at least one of positional deviation and den sity deviation ofthe image based on the correction value and a changing unit which is configured to execute at least one of a first changing process of changing a permissible range of a correction value for positional deviation according to a status of a factor causing a change in a position of an image and a second changing process of changing a permissible range of a correction value for density deviation according to a status of a factor causing a change in a density of an image 13 Claims 9 Drawing Sheets 101 U S Patent Nov 12 2013 Sheet 1 of 9 FIG 1 100 CONTROL UNIT
8. US008582993B2 a2 United States Patent Murayama et al US 8 582 993 B2 Nov 12 2013 10 Patent No 45 Date of Patent 54 IMAGE FORMING APPARATUS THAT CHANGES A PERMISSIBLE RANGE OF A CORRECTION VALUE 75 Inventors Kentaro Murayama Kasugai JP Osamu Takahashi Nagoya JP 73 Assignee Brother Kogyo Kabushiki Kaisha Nagoya shi Aichi ken JP otice ubject to any disclaimer the term of this Noti Subj disclai h fthi patent is extended or adjusted under 35 U S C 154 b by 201 days Appl No 13 072 823 Q1 22 Filed Mar 28 2011 Prior Publication Data US 2011 0318032 A1 Dec 29 2011 65 30 Foreign Application Priority Data Jun 28 2010 2010 146582 JP 51 Int CI G03G 15 00 G03G 15 01 G03G 21 00 U S CI USPC 399 49 399 81 399 301 Field of Classification Search USPC 399 49 301 81 347 116 See application file for complete search history 2006 01 2006 01 2006 01 52 58 56 References Cited U S PATENT DOCUMENTS 1 2002 Munakata 5 2008 Murakami 6 335 747 Bl 2008 0118257 Al 2008 0279599 Al 11 2008 Nagatsuka 399 301 2010 0086317 Al 4 2010 Kadokura wee 399 11 READ OUT CORRECTION VALUES ACQUIRE DATA OF FACTOR CAUSING CHANGE FOREIGN PATENT DOCUMENTS JP H08 262829 A 10 1996 JP H11 119504 A 4 1999 JP H11 218989 A 8 1999 JP 2001 109218 A 4 2001 JP 2002 244393 A 8 2002 JP 2005 234454 A 9 2005 JP 2008 0
9. VIATION S204 AMOUNT OF DEVIATION IS WITHIN PREDETERMINED NO UPDATE AUTOMATIC CORRECTION VALUE NOTIFY ERROR S211 ADJUSTMENT COLOR THAT HAS NOT YET DETERMINED REMAINS NO U S Patent Nov 12 2013 Sheet 9 of 9 US 8 582 993 B2 FIG 10 PRINTING PROCESS READ OUT CORRECTION VALUES ACQUIRE IMAGE DATA 302 303 FORM IMAGE US 8 582 993 B2 1 IMAGE FORMING APPARATUS THAT CHANGES A PERMISSIBLE RANGE OF A CORRECTION VALUE CROSS REFERENCE TO RELATED APPLICATION This application claims priority from Japanese Patent Application No 2010 146582 filed on Jun 28 2010 the entire subject matter of which is incorporated herein by ref erence TECHNICAL FIELD Aspects ofthe present invention relate to an image forming apparatus that adjusts a position or density of an image based on a correction value input by a user BACKGROUND An image forming apparatus performs an image adjust ment so that a position or density of an image is not deviated For example an image forming apparatus has been known which receives a correction value input by a user through an operation panel or a printer driver and performs an image adjustment of adjusting positional deviation or density devia tion based on the correction value when forming an image JP A 2005 234454 describes a technique of acquiring the correction value by the user input which includes printing a pattern image for positional deviati
10. cquiring the total assumed expansion amount of the positional deviation in addition to the method of preparing tables corresponding to the respective factors and referring to the tables to acquire the assumed expansion amount for each of the factors a calcula tion equation for calculating a total assumed expansion amount of positional deviation may be prepared and then a total assumed expansion amount of positional deviation may be calculated based on a plurality of factors For example a total assumed expansion amount of positional deviation may be calculated by a following equation 1 A total assumed expansion amount of positional deviation Cxthe number of times of opening 20 25 30 35 40 45 50 55 60 65 8 and closing the cover 7xchange in tempera ture Bxthe number of rotations of the belt driv ing droller Sxmaximum acceleration 1 In the equation C T B and S are coefficients for calculat ing the individual expansion amounts of the respective fac tors Specifically C indicates an amount of positional devia tion peronetime ofopening and closing the cover T indicates an amount of positional deviation per unit temperature B indicates an amount of positional deviation per one rotation of the driving roller 74 of the conveyance belt 7 and S indicates an amount of positional deviation per unit acceleration unit voltage The C T B and S may be fixed values or changed according to the oth
11. cquiring unit to acquire the correction value 10 The image forming apparatus according to claim 9 wherein the image forming unit is configured to print a different pattern image according to the permissible range 11 The image forming apparatus according to claim 8 further comprising an automatic acquiring unit which is configured to form a mark for detecting at least one of the positional deviation and the density deviation and to acquire an amount of deviation by measuring the mark wherein the changing unit is configured to execute at least one of the first changing process and the second chang ing process when the automatic acquiring unit acquires the amount of deviation 12 The image forming apparatus according to claim 8 wherein the image forming unit is configured to form images of a plurality of colors and wherein the changing unit is configured to determine the permissible range for each of the colors independently 13 The image forming apparatus according to claim 8 wherein the factor includes one of a temperature a humidity and an operation amount of the apparatus
12. d on the current correction value The above image forming apparatus may include a limit ing unit which is configured to limit an input range of the correction value by the manual acquiring unit based on the permissible range The numerical value input range by the user input is limited based on the permissible range so that it is possible to prevent an inappropriate correction value from being acquired in advance Further the image forming unit may be configured to print on arecoding sheet a pattern image to be referred to when the user input is received by the manual acquiring unit to acquire the correction value According to this configuration it is possible to recognize an amount of deviation that actually occurs on the printing sheet and to input the manual correc tion value according to types of the sheet Furthermore the image forming unit may be configured to print a different US 8 582 993 B2 13 pattern image according to the permissible range The pattern imageis changed according to the permissible range changed so that it is possible to allow a user to recognize that the permissible range has been changed and to prevent an inap propriate value from being input Further the image forming apparatus may further include an automatic acquiring unit which is configured to form a mark for detecting at least one of positional deviation and density deviation and acquire an amount of deviation by measuring the mark and the cha
13. deviation added thereto In the meantime zero 0 is set as an initial value of the manual correction value Then the registration pattern 66 is formed on the convey ance belt 7 by using the automatic correction value and the manual correction value which are read out in S201 S202 Then the mark sensor 61 detects the registration pattern 66 S203 Then the amounts of positional deviations of the respective adjustment colors are calculated based on signals from the mark sensor 61 S204 Then it is determined whether the amount of positional deviation of each adjustment color which is obtained in S204 is within a predetermined range S205 The predetermined range is a range within which the positional deviation can be adjusted and is stored in the ROM 32 in advance The case where the amount of positional deviation exceeds the prede termined range includes a case where the amount of posi tional deviation is so large that the adjacent marks are over lapped with each other for example This kind of large amount of positional deviation could be caused by an error input ofthe manual correction value by a user which changes 0 5 20 30 40 45 65 10 a position of a mark for example In addition when the conveyance belt 7 has a damaged part and the mark sensor 61 falsely detects the damaged part as a mark an inappropriate amount of positional deviation can be caused Also when the mark sensor 61 is out
14. e to the accompanying drawings In the illustrative embodiments the present invention is applied to a multi function peripheral MFP having a color printing function Configuration of MFP As shown in FIG 1 an MFP 100 of this illustrative embodiment includes a control unit 30 having a CPU 31 a ROM 32 a RAM 33 an NVRAM non volatile RAM 34 an ASIC 35 a network interface 36 and a FAX interface 37 In addition the control unit 30 is electrically connected to an image forming unit 10 that forms an image on a sheet an image reading unit 20 that reads out an image of a sheet and an operation panel 40 that displays an operation situation and receives an input operation by a user The CPU 31 executes operations for implementing various functions such as an image reading function an image form ing function a FAX data transmission reception function and an image adjustment function described later and functions as a center of control The ROM 32 stores therein various control programs for controlling the MFP 100 various set tings initial values and the like The RAM 33 is used as a work area from which the various control programs are read out or a storage area that temporarily stores image data The NVRAM 34 is a non volatile storage device and is used as a storage area that preserves various settings image data and the like Based on the control programs read out from the ROM 32 or signals transmitted from various sensors the CPU
15. ensor 61 is provided downstream from the pro cess units 50Y 50M 50C 50K and upstream from the fixing 20 25 30 35 40 45 50 55 60 65 4 device 8 with respect to the conveyance direction of the sheet and detects a pattern for image adjustment formed on the conveyance belt 7 Specifically as shown in FIG 3 the mark sensor 61 includes two sensors i e a sensor 61R that is arranged at a right side of a width direction of the conveyance belt 7 and a sensor 61L that is arranged at a left side thereof Each of the sensors 61R 61L is a reflection type optical sensor having a pair of a light emitting element 62 for example LED and a light receiving element 63 for example photo transistor The mark sensor 61 illuminates light to a surface dotted ranges E in FIG 3 of the conveyance belt 7 in an oblique direction by the light emitting elements 62 and receives the light by the light receiving elements 63 respectively The mark sensor can detect a mark 66 for image adjustment mark 66 of FIG 3 is an example of a mark for positional deviation correction by a difference between an amount of reflection light received when the mark for image adjustment passes and an amount of reflection light received that is directly received from the conveyance belt 7 Image Adjustment in MFP Next the image adjustment in the MFP 100 will be described In the MFP 100 regarding the image adjustment a positional deviation cor
16. er variables In addition the parameters applied to the equation 1 are not limited to the number of times of opening and closing the cover and the like In addition the permissible range ofthe manual correction value is determined for each ofthe adjustment colors In other words the more distant from the transfer point of the refer encecolor the amount of deviation tends to be greater such as the speed difference ofthe conveyance belt 7 the temperature difference in the apparatus and the like Therefore the more distant from the reference color the permissible range is set to be larger For example in this illustrative embodiment the K color is the reference color and the adjustment colors are more distant from the K color in order of C M and Y colors refer to FIG 2 Accordingly 1 is added to the total expansion amount of positional deviation in the M color and 2 is added to the total expansion amount of positional deviation in the Y color Thereby when 10 to 10 dots are the initial value ofthe permissible range and the total expansion amount of posi tional deviation acquired from the respective tables is 3 the permissible range of the C color is 13 to 13 dots the per missible range of the M color is 14 to 14 dots and the permissible range of the Y color is 15 to 15 dots After calculating the permissible ranges in S103 the per missible range is adjusted by using the current automatic and manual correcti
17. f an image for example of the image adjust ment is provided and the permissible ranges corresponding to the subjects of the image adjustment are changed periodi cally or according to statuses of the factors causing a change in each subject of the image adjustment In this case when acquiring an input value by a user or printing the pattern image 86 the database storing the permissible ranges may be referred to in order to determine whether to acquire it In this configuration the permissible ranges of the respective manual correction values which are stored in the database may be initialized when the automatic correction value of S206 is updated In the above illustrative embodiment when printing the pattern image 86 on the sheet the pattern image having dif ferent number of marks is printed according to the permis sible range However the present invention is not limited thereto For example the interval between the marks may be changed according to the permissible range In other words when the permissible range is narrow the interval between the marks is narrowed and when the permissible range is wide the interval between the marks is widened The present invention provides illustrative non limiting embodiments as follows Animage forming apparatus includes a manual acquiring unit which is configured to receive a user input to acquire a 0 20 30 40 45 50 65 12 correction value an image formin
18. g unit which is configured to form an image while adjusting at least one of positional deviation and density deviation of the image based on the correction value and a changing unit which is configured to execute at least one of a first changing process of changing a permissible range of a correction value for positional devia tion according to a status of a factor causing a change in a position of an image and a second changing process of changing a permissible range ofa correction value for density deviation according to a status of a factor causing a change in a density of an image The above image forming apparatus forms an image by using a correction value input by a user manual correction value According to a status of a factor causing positional deviation and density deviation the image forming apparatus can change permissible ranges of the manual correction val ues corresponding to the deviations Specifically in the changing process the image forming apparatus can execute at least one of the first changing process of changing a permis sible range of a correction value for positional deviation according to a status of a factor causing a change in a position of an image and a second changing process of changing a permissible range of a correction value for density deviation according to a status of a factor causing a change in a density of an image The factor causing the change in the position or density of an image may include an
19. ge of a correction value for density deviation according to a status of a factor caus ing a change in a density of an image wherein the changing unit is configured to determine the permissible range by using a current correction value 2 The image forming apparatus according to claim 1 further comprising a limiting unit which is configured to limit an input range of the correction value by the manual acquiring unit based on the permissible range 3 The image forming apparatus according to claim 1 wherein the image forming unit is configured to print on a recording sheet a pattern image to be referred to when the input is received by the manual acquiring unit to acquire the correction value 4 The image forming apparatus according to claim 3 wherein the image forming unit is configured to print a different pattern image according to the permissible range 5 The image forming apparatus according to claim 1 further comprising an automatic acquiring unit which is configured to form a mark for detecting at least one of the positional deviation 15 20 25 30 35 45 50 55 14 and the density deviation and to acquire an amount of deviation by measuring the mark wherein the changing unit is configured to execute at least one of the first changing process and the second chang ing process when the automatic acquiring unit acquires the amount of deviation 6 The image forming apparatus according to claim 1
20. in a density of an image According to the above configuration there is provided an image forming apparatus that performs an image adjustment based on a correction value input by a user and can suppress a quality of an image from being deteriorated BRIEF DESCRIPTION OF THE DRAWINGS The above and other aspects of the present invention will become more apparent and more readily appreciated from the 20 25 30 35 40 45 50 55 60 65 2 following description of illustrative embodiments of the present invention taken in conjunction with the attached drawings in which FIG 1 is a block diagram showing an electrical configura tion of an MFP FIG 2 shows a schematic configuration of an image form ing unit of the MFP shown in FIG 1 FIG 3 shows an arrangement of mark sensors FIGS 4A and 4B show a printing example of a pattern image FIG 5 is a flow chart showing a sequence of a manual acquiring process FIG 6 shows a printed page number limiting table FIG 7 shows a temperature limiting table FIG 8 shows a printing example of a pattern image on which a current correction value is reflected FIG 9 is a flow chart showing a sequence of an automatic acquiring process and FIG 10 is a flow chart showing a sequence of a printing process DETAILED DESCRIPTION Hereinafter an image forming apparatus and an image forming system according to illustrative embodiments will be described with referenc
21. inputting the manual correction value a value within the permissible range thereof is received so that an appropriate manual correction value is acquired In addi tion when printing the pattern image 86 a pattern image suitable for the permissible range thereof is printed so that it is expected that an appropriate manual correction value is input As a result itis possible to avoid acquiring an inappro priate correction value and to thus suppress a quality of an image from being deteriorated US 8 582 993 B2 11 While the present invention has been shown and described with reference to certain illustrative embodiments thereof it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope ofthe invention as defined by the appended claims For example the image forming apparatus is not limited to the MFP In other words the inventive concept of the present invention can be applied to any apparatus having a printing function such as printer copier FAX apparatus and the like In addition the image forming apparatus is not limited to an electro photographic type and may be an inkjet type Further the MFP 100 ofthe illustrative embodiment is a direct transfer tandem type However the MFP may be an intermediate transfer type or 4 cycle type In the above illustrative embodiment the MFP has the color printing function However the inventive c
22. n the sub scanning direction are respectively calculated The intervals between the mark of the reference color and the adjustment colors are changed when positional deviation occurs in the sub scanning direction Therefore it is possible to specify an amount of deviation of the adjustment color relative to the reference color in the sub scanning direction Based on the amount of deviation a correction value by the automatic correction hereinafter referred to as automatic correction value is calculated The automatic correction values are stored in the NVRAM 34 It is noted that the configuration of the registration pattern 66 is just illustrative and is not limited to the above The registration pattern may be a general image pattern that is used to correct the positional deviation For example the registration pattern may include a pair of two rod shaped marks wherein at least one is inclined by a predetermined angle to a straight line following the main scanning direction Such registration pattern can specify an amount of deviation in the main scanning direction as well as in the sub scanning direction In the meantime the manual correction is executed by a user s operation The operation panel 40 is provided with a switch button for switching into a manual correction mode that enables an input of a correction value A user pushes the switch button inputs a desired correction value and then pushes an OK button When the OK butto
23. n check the positional deviation of the sub scanning direction The printing of the pattern image 86 is executed when the switch button is pushed Accordingly a user can determine a correction value by referring to the sheet on which the pattern image 86 is printed In the meantime it may be also possible that the operation panel 40 is provided with a button for printing a pattern image and a user prints the pattern image 86 at any timing In the correction process an actual correction value is determined by using the automatic correction value and the manual correction value which are stored in the NVRAM 34 Based on the actual correction value process conditions for example exposure position speed ofthe conveyance belt 7 or photosensitive member of the adjustment color are adjusted so that a position of an image of the adjustment color is matched with a position of an image of the reference color In the meantime the density deviation adjustment also includes the automatic correction and the manual correction For example in the automatic correction density patterns having density differences in the sub scanning direction are formed by the respective process units 50Y 50M 50C 50K Then amounts of reflected light from the density patterns are detected by the common sensor to the positional deviation correction or another optical sensor In this illustrative embodiment the detection is performed by the sensor 61L for example Acc
24. n is pushed the MFP 100 acquires the input value to release the manual correction mode Based on the input value a correction value by the manual correction hereinafter referred to as manual correction value is calculated The manual correction value is stored in the NVRAM 34 The MFP 100 has a pattern printing function of printing a pattern image that is referred to when a user inputs a correc tion value As the pattern image a mark group as shown in FIG 4A or 4B hereinafter referred to as pattern image 86 is printed In the pattern image 86 of this illustrative embodiment marks of the same color having a rectangular rod shape are formed at a constant interval in the main scanning direction horizontal direction in FIG 4A In the example of FIG 4A the reference coloris black K color and the adjustment color is cyan C color and an interval of the marks 86C of the adjustment color are narrower than that of the marks 86K of the reference color by n dots n is natural number and n 1 in this illustrative embodiment The marks 86K of the reference color are formed as the number 25 in FIGS 4A and 4B corresponding to a permissible range of the manual correc tion value for the adjustment color and numbers 12 to 12 in FIG 4 corresponding to the permissible range are added in ascending order from the left The marks 86C of the adjust ment color is the same as the number of the marks of the reference color and a zero ma
25. nging unit may be configured to execute at least one of the first changing process and the second changing process when the automatic acquiring unit acquires the amount of deviation In this configuration if using the amount of deviation by the automatic acquiring unit the correction value that is specified by the amount of deviation acquired by the automatic acquiring unit is recon sidered Therefore it may be preferable to change the permis sible range of the correction value accordingly In addition the image forming unit may form images of a plurality of colors and the changing unit may be configured to determine a permissible range for each of the colors inde pendently The permissible range can be set for each of the colors so that it is possible to set the permissible range more appropriately What is claimed is 1 An image forming apparatus comprising a manual acquiring unit which is configured to receive an input to acquire a correction value an image forming unit which is configured to form an image while adjusting at least one of positional deviation and density deviation of the image based on the correc tion value and a changing unit which is configured to execute at least one of a first changing process of changing a permissible range of a correction value for positional deviation according to a status of a factor causing a change in a position of an image and a second changing process of changing a permissible ran
26. of order even the amount of positional deviation itself cannot be acquired For an adjustment color having an amount of positional deviation that is within the predetermined range S205 YES the automatic correction value corresponding to the adjust ment color is updated S206 Specifically the amount of positional deviation acquired in S204 is added to the current automatic correction value and the result is stored in the NVRAM 34 as a new automatic correction value In the meantime when the automatic correction value is updated the number of printed pages is reset to zero Accordingly the assumed expansion amount with respect to the number of printed pages would be zero and the permissible range of the manual correction value is thus narrowed In the meantime for an adjustment color having an amount of positional deviation that exceeds the predetermined range S205 NO an error is notified which indicates that the automatic correction value is failed to be acquired S211 The notification modes include message display on a display unit of the operation panel 40 generation of an alarm sound and writing of an error log for example After S206 or S211 it is determined whether an adjustment color that has not yet determined is remaining in S205 S207 When an adjustment color that has not yet determined is remaining S207 YES the process returns to S205 and determines the amount of positional deviation of the adjust ment color
27. on correction on a sheet and allows a user to determine and input a correction value based on a printing result thereof However the above image forming apparatus has a follow ing problem That is in the image forming apparatus that acquires the correction value by the user input when the input correction value is considerably inappropriate a quality of an image may be remarkably deteriorated SUMMARY Accordingly it is an aspect of the present invention to provide an image forming apparatus that can suppress per forms an image adjustment based on a correction value input by a user and can suppress a quality of an image from being deteriorated According to an illustrative embodiment of the present invention there is provided an image forming apparatus com prising a manual acquiring unit which is configured to receive a user input to acquire a correction value an image forming unit which is configured to form an image while adjusting at least one of positional deviation and density deviation of the image based on the correction value and a changing unit which is configured to execute at least one of a first changing process of changing a permissible range of a correction value for positional deviation according to a status of a factor causing a change in a position of an image and a second changing process of changing a permissible range of a correction value for density deviation according to a status of a factor causing a change
28. on values that are acquired in S101 S104 For example providing that an image adjustment of 3 dots is performed based on the current actual correction value calculated by the automatic and manual correction values when the permissible range acquired in S103 is 12 to 12 dots an actual correctable range is 9 to 15 dots Accordingly when 10 is input for example since the shift of 3 dots has been already scheduled the total amount of correction would be 13 which exceeds the permissible range Thus in this illustrative embodiment the permissible range is adjusted to 9 to 15 dots so that a value equal to or smaller than 10 cannot be input After that the pattern image 86 is printed on a sheet S105 The number of marks of each color in the pattern image 86 is different according to the permissible ranges determined in 103 In addition since the adjustment is performed on the basis of the current correction value in S104 the number of marks may be different in positive and negative sides In the above example by the adjustment in 104 the nega tive number side is limited up to 9 and the marks are printed up to 9 so that it is expected that an inappropriate numerical value is prevented from being input However when the posi tive number side is printed up to 15 it may cause a user to misunderstand that a numerical value within a range of 15 to 15 dots can be input Accordingly the number of marks to be
29. oncept ofthe present invention can also be applied to a monochrome print ing apparatus inasmuch as it performs the positional deviation correction or density deviation correction In the above illustrative embodiment the pattern image is printed on the sheet when performing the manual acquiring process However a configuration of receiving an input from a user without performing such printing may be also possible In addition when printing the pattern image a type of the sheet may be designated In the above illustrative embodiment the actual correction value is determined by using the automatic correction value and the manual correction value However the present inven tion is not limited thereto For example it may be possible to determine an actual correction value without using the cor rection value having older update date between the automatic and manual correction values In this case the registration pattern 66 in the automatic correction or pattern image 86 in the manual correction are prepared without using the correc tion value having the older update date Inthe above illustrative embodiment the permissible range is determined when switching to the manual correction mode or when printing the pattern image 86 However the timing of changing the permissible range is not limited thereto For example it may be possible that a database in which the permissible ranges is stored for each of the subjects position and density o
30. operation amount and environmental changes such as temperature and humidity That is in the above image forming apparatus there are permissible ranges ofthe manual correction values for each of subjects position and density of an image for example of the image adjustment and the permissible ranges of the manual correction values corresponding to the subjects ofthe image adjustment are changed according to the statuses ofthe factors causing the change in the subjects ofthe image adjust ment Therefore when inputting a correction value a value within the permissible range thereof is received so that an appropriate manual correction value can be acquired accord ing to the statuses of the respective factors Alternatively when printing a pattern image that is referred to when input ting the manual correction value a pattern image suitable for the permissible range thereof is printed and it can be thus expected that the appropriate manual correction value is input according to the statuses ofthe respective factors As a result it is possible to avoid acquiring an inappropriate correction value and to thus suppress a quality of an image from being deteriorated Inthe above the changing unit may be configured to deter mine the permissible range by using a current correction value When the correction value has been already acquired a correctable range may be changed Accordingly it may be preferable to determine the permissible range base
31. ording to the amounts of reflected light the densities are specified and differences with a target density are calculated as automatic correction values In the manual correction a manual correction value can be received through a user input Then in the correction process an actual cor rection value is calculated based on the correction values and the process conditions for example exposure intensity exposure range and developing bias of the respective colors are adjusted to maintain a target density based on the actual correction value Sequence of Changing Permissible Range of Manual Cor rection Value The MFP 100 has a function of changing a permissible range ofthe manual correction value according to statuses of factors causing a change in a position or density of an image In the following a sequence of changing the permissible range of the manual correction value will be described together with a sequence of executing the positional deviation correction Manual Acquiring Process A sequence of the manual acquiring process that is an acquiring process for manual correction will be described with reference to a flow chart of FIG 5 The manual acquiring process is executed by the CPU 31 when the switch button provided to the operation panel 40 is pushed US 8 582 993 B2 7 First the automatic correction value and the manual cor rection value are read out from the NVRAM 34 S101 Then data is acquired which indicates
32. pparatus Then the assumed expansion amount corresponding to the current number of printed pages and the assumed expansion amount corresponding to the current temperature in the appa ratus and both the assumed expansion amounts are summed up For example providing that the number of printed pages is 1 500 pages and the difference between the temperature in the apparatus and the reference temperature is 11 degree C the assumed expansion amount 2 is acquired from the printed page number limiting table 341 and the assumed expansion amount 1 is acquired from the temperature lim iting table 342 respectively That is the summed value 3 of both the assumed expansion amounts would be a total assumed expansion amount of positional deviation Then the permissible range of the manual correction value is deter mined while reflecting the total assumed expansion amount of positional deviation For example if 10 to 10 dots is an initial value of the permissible range the permissible range would be 13 to 13 dots In the meantime the parameter indicating the status of the factor causing the positional deviation in the image are not limited to the number of printed pages and the temperature in the apparatus For example an amount of change may be determined by ON time period humidity in the apparatus a remaining amount of toner the number of times of opening and closing the cover and the like Further regarding the method of a
33. printed is made to be within the range determined in S103 12 to 12 dots in the above example In other words in the above example as shown in FIG 8 marks of 9 to 12 are printed After S105 an input of a correction by a user is waited The user inputs a correction value with the operation panel 40 US 8 582 993 B2 9 After that it is determined whether an instruction to com plete the input of the correction value is input S106 When an instruction to complete the input of the correction value is not input S106 NO it is determined whether a cancel instruction is input S111 When a cancel instruction is also not input S111 NO the process returns to S106 When a cancel instruction is input S111 YES the manual acquiring process ends Whenan instruction to complete the input ofthe correction value is input S106 YES the input values of the respective adjustment colors are acquired which are input as correction values S107 Accordingly the manual correction values of the respective adjustment colors are updated S108 Specifi cally the input value is added to the current manual correction value and the result is stored in the NVRAM 34 as a new manual correction value After S108 the manual acquiring process ends In the meantime if a numerical value exceeding the per missible range has been input when an instruction to com plete the input of the correction value is input a message is issued indicating that
34. rection that adjusts positions of images of the respective colors and a density deviation cor rection that adjusts densities of the respective colors are per formed Both image adjustments include an acquiring pro cess of acquiring amounts of deviation of adjustment colors from a reference color and acquiring correction values speci fied by the amounts of deviation and a correcting process of correcting an image based on the correction values Herein after the image adjustment will be described with reference to the positional deviation correction First the acquiring process of the positional deviation cor rection will be described The MFP 100 has two modes of acquiring process which includes an automatic correction and a manual correction The automatic correction is to adjust an image to an ideal position that is set for the MFP 100 The manual correction is to reflect a user s preference or to sub stitute for the automatic correction when the automatic cor rection does not function properly In the automatic correction a registration pattern that is a pattern image for detecting an amount of positional deviation and the mark sensor 61 detects the registration pattern and thus calculates an amount of deviation A correction value based on the amount of deviation is automatically acquired In the manual correction a user inputs a numerical value through the operation panel 40 so that a correction value is manually acquired Here
35. rk is printed so that its position ofthe main scanning direction is matched with a zero mark of the reference color FIG 4A shows a case where positional deviation does not occur and the mark of the reference color and the mark of the adjustment color are matched at a zero position FIG 4B shows a printing example where positional devia tion occurs by 3 dots to the left In this case the mark of the 20 25 30 35 40 45 50 55 60 65 6 reference color and the mark of the adjustment color are not matched at the zero position and are matched at 3 position Thereby a user can recognize that positional deviation of 3 dots occurs in the left In this case the user can adjust the positional deviation of the C color by inputting 3 as a cor rection value When positional deviation of 3 dots occurs in the right the user inputs 3 as a correction value In this illustrative embodiment the K color is the reference color and the user can also input correction values for the M and Y colors in the same manner in addition to the C color In the meantime the configuration of the pattern image 86 is just illustrative and is not limited to the above The pattern image may be a general image pattern that is used to correct the positional deviation For example the mark group includ ing the pattern image 86 is formed at a constant interval in the sub scanning direction vertical direction in FIG 4A so that a user ca
36. sponding to an image formed on a sheet is thus formed on the photosen sitive member Then toner is supplied to the photosensitive member through a developing device Thereby the electro static latent image on the photosensitive member becomes a visible image as a toner image The conveyance belt 7 is an endless belt member that is wound around the conveyance rollers 73 74 and is made ofa resin material such as polycarbonate and the like The con veyance belt 7 is rotated in a counterclockwise direction as the conveyance roller 74 is rotated Thereby the sheet put on the conveyance belt is conveyed from the registration rollers 72 toward the fixing device 8 The image forming unit 10 picks up the sheets accommo dated in the sheet feeding tray 91 one by one and conveys the sheet onto the conveyance belt 7 Then the image forming unit 10 transfers the toner image formed in the process unit 50 to the sheet At this time for a case of a color printing toner images are formed by the respective process units 50Y 50M 50C 50K and are then overlapped with each other on the sheet In the meantime for a case of a monochrome printing a toner image is formed only by the process unit 50K and is then transferred on the sheet Thereafter the sheet on which the toner images are transferred is conveyed to the fixing device 8 and is then heat fixed on the sheet Then the sheet after the fixing is discharged to the sheet discharge tray 92 The mark s
37. that has not yet been determined When the deter mination of S205 is completed for all adjustment colors S207 NO the automatic acquiring process ends Printing Process Next a sequence of the printing process of printing image data will be described with reference to a flow chart of FIG 10 The printing process is executed by the CPU 31 when a print instruction is received from the operation panel 40 or a print job is received from an information processing appara tus connected to the MFP 100 First the automatic correction value and the manual cor rection value are read out from the NVRAM 34 S301 Then image data to be printed is acquired S302 The processes of 301 and S302 may be executed in a reverse order or at the same time Then an actual correction value is determined by using both the automatic correction value and the manual correction value which are read out in S301 and an image is formed while adjusting the process conditions of the adjustment col ors so that positions of images of the adjustment colors are matched at positions of images ofthe reference color S303 After S303 the printing process ends As described above in the MFP 100 according to the illustrative embodiment the permissible range is set for the manual correction value and is changed according to the factor the number of printed pages temperature in the appa ratus and the like causing a change in a subject of the image adjustment When
38. to the respective process units 50Y 50M 50C 50K a conveyance belt 7 that conveys a sheet to transfer positions of the respective process units 50Y 50M 50C 50K and a mark sensor 61 that detects a pattern image formed on the conveyance belt 7 In addition the image forming unit 10 is provided therein with a conveyance path 11 one dotted and dashed line in FIG 2 having a substantial S shape so that the sheet accommo dated in the sheet feeding tray 91 positioned at a bottom passes through a feeder roller 71 registration rollers 72 the process unit 50 and the fixing device 8 and is then guided to the sheet discharge tray 92 through sheet discharge rollers 76 The process unit 50 can form a color image and includes the process units corresponding to respective colors of yellow Y magenta M cyan C and black K in parallel Spe cifically the process unit 50 has the process unit 50Y that forms an image of a Y color the process unit 50M that forms an image of an M color the process unit 50C that forms an image of a C color and the process unit 50K that forms an image of a K color The respective process units 50Y 50M 50C 50K are arranged at a predetermined interval in a con veyance direction of the sheet Inthe process unit 50 a surface ofa photosensitive member is uniformly charged by a charging device Then the photo sensitive member is exposed by the light from the exposure device 53 and an electrostatic latent image corre
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