# US 2014/0153943 A1 · Image forming apparatus and conveyance control method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0153943 A1 - Document ID: US20140153943A1 - Status: Published application - Kind: A1 - Application number: 14/093,740 - Filed: 2013-12-02 - Published: 2014-06-05 - Earliest claimed: 2012-12-03 - Assignees: Ricoh Company, Ltd. - Inventors: Tatsuya MIYADERA; Akinori YAMAGUCHI; Masatoshi MURAKAMI - Web page: https://patentgrep.com/patent/US20140153943A1 ## CPC - G03G 15/5062: {by measuring the characteristics of an image on the copy material} - G03G 15/01: for producing multicoloured copies - G03G 15/0189: {primary transfer to an intermediate transfer belt (G03G15/0184 takes precedence)} - G03G 15/5058: {using a test patch} - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract An image forming apparatus including: a conveyance mechanism conveying a first pattern formed by a first image forming unit among image forming units, a second pattern formed by a second image forming unit among the image forming units; a detection unit detecting the first pattern and the second pattern; and a control unit controlling, when a first condition is satisfied, a timing of conveying a recording sheet having the image formed by the first image forming unit is transferred based on a first time required after the formation of the first pattern and before detecting the first pattern, and controlling, when a second condition is satisfied, a timing of conveying the recording sheet having the image formed by the second image forming unit is transferred based on a second time required after the formation of the second pattern and before detecting the second pattern. ## Claims ### Claim 1 An image forming apparatus comprising: a plurality of image forming units configured to form an image in different colors; a conveyance mechanism configured to convey a first pattern formed using at least a first image forming unit among the image forming units, that forms the image in a first color, and convey a second pattern formed using a second image forming unit among the image forming units, that forms the image in a second color; a detection unit configured to detect the first pattern conveyed by the conveyance mechanism and the second pattern conveyed by the conveyance mechanism; and a control unit configured to control, when a first condition is satisfied, a timing of conveying a recording sheet to which the image formed using at least the first image forming unit is transferred on the basis of a first time required after the formation of the first pattern and before the detection of the first pattern by the detection unit, and the control unit configured to control, when a second condition is satisfied, a timing of conveying the recording sheet to which the image formed using the second image forming unit is transferred on the basis of a second time required after the formation of the second pattern and before the detection of the second pattern by the detection unit. ### Claim 2 (depends on 1) The image forming apparatus according to claim 1, further comprising a storage unit configured to store a first reference value as a reference value of the first time and a second reference value as a reference value of the second time, wherein the control unit controls, when the first condition is satisfied, the timing of conveying the recording sheet on the basis of a difference between the first time and the first reference value, and the control unit controls, when the second condition is satisfied, the timing of conveying the recording sheet on the basis of a difference between the second time and the second reference value. ### Claim 3 (depends on 1) The image forming apparatus according to claim 1, wherein the first color is a color other than black used in color image formation, the second color is a color other than black, the first image forming unit is an image forming unit located in the most upstream side of a conveying direction of the conveyance mechanism among the image forming units for performing color image formation in the image forming units, and the second image forming unit is an image forming unit located in the most upstream side of the conveying direction of the conveyance mechanism among the image forming units for performing monochromatic image formation in the image forming units. ### Claim 4 (depends on 3) The image forming apparatus according to claim 3, wherein the first pattern is formed using the image forming unit performing color image formation among the image forming units, the second pattern is formed using the image forming unit performing monochromatic image formation among the image forming units, and the control unit controls an exposure timing for the color using a detection result of the first pattern from the detection unit, and controls an exposure timing for the monochrome using a detection result of the second pattern from the detection unit. ### Claim 5 (depends on 1) The image forming apparatus according to claim 1, further comprising a buffer mechanism configured to absorb expansion and contraction of the conveyance mechanism, wherein the buffer mechanism is provided between the image forming unit located in the most downstream side of a conveying direction of the conveyance mechanism and the detection unit. ### Claim 6 An image forming apparatus comprising: a plurality of image forming units configured to form an image in different colors; a conveyance mechanism configured to convey a first pattern formed using at least a first image forming unit among the image forming units, that forms the image in a first color, and convey a second pattern formed using a second image forming unit among the image forming units, that forms the image in a second color; a detection unit configured to detect the first pattern conveyed by the conveyance mechanism and the second pattern conveyed by the conveyance mechanism; a storage unit configured to store a first temperature at the detection of the first pattern and a second temperature at the detection of the second pattern; and a control unit configured to control, when the first pattern has been previously detected, a timing of conveying a recording sheet to which the image formed using at least the first image forming unit is transferred on the basis of a first time required after the formation of the first pattern and before the detection of the first pattern by the detection unit, the first temperature, and a current temperature, and the control unit configured to control, when the second pattern has been previously detected, a timing of conveying the recording sheet to which the image formed using the second image forming unit is transferred on the basis of a second time required after the formation of the second pattern and before the detection of the second pattern by the detection unit, the second temperature, and the current temperature. ### Claim 7 (depends on 6) The image forming apparatus according to claim 6, wherein the storage unit further stores a first reference value as a reference value of the first time and a second reference value as a reference value of the second time, and the control unit controls, when the first pattern has been previously detected, the timing of conveying the recording sheet to which the image formed by using at least the first image forming unit is transferred on the basis of a value obtained by adding a value based on a difference between the first temperature and the current temperature to a value based on a difference between the first time and the first reference value, and the control unit controls, when the second pattern has been previously detected, the timing of conveying the recording sheet to which the image formed by using the second image forming unit is transferred on the basis of a value obtained by adding a value based on a difference between the second temperature and the current temperature to a value based on a difference between the second time and the second reference value. ### Claim 8 (depends on 6) The image forming apparatus according to claim 6, wherein the first temperature, the second temperature, and the current temperature are temperatures inside or outside the apparatus. ### Claim 9 (depends on 6) The image forming apparatus according to claim 6, wherein the first color is a color other than black used in color image formation, the second color is a color other than black, the first image forming unit is an image forming unit located in the most upstream side of a conveying direction of the conveyance mechanism among the image forming units for performing color image formation in the image forming units, and the second image forming unit is an image forming unit located in the most upstream side of a conveying direction of the conveyance mechanism among the image forming units for performing monochromatic image formation in the image forming units. ### Claim 10 (depends on 9) The image forming apparatus according to claim 9, wherein the first pattern is formed using the image forming unit performing color image formation among the image forming units, the second pattern is formed using the image forming unit performing monochromatic image formation among the image forming units, and the control unit controls an exposure timing for the color using a detection result of the first pattern from the detection unit, and controls an exposure timing for the monochrome using a detection result of the second pattern from the detection unit. ### Claim 11 (depends on 10) The image forming apparatus according to claim 10, wherein the control unit corrects an image position by controlling the exposure timing when temperature has changed over a certain range or a power-off time has continued for a certain period. ### Claim 12 (depends on 11) The image forming apparatus according to claim 11, further comprising a controller, wherein the power-off time is measured using a real-time clock included in the controller or an active timer-up signal output from the controller. ### Claim 13 (depends on 12) The image forming apparatus according to claim 12, wherein the power-off time is measured from a time when a driving motor for the image forming unit performing the monochromatic image formation stops finally. ### Claim 14 (depends on 10) The image forming apparatus according to claim 10, wherein the control unit corrects an image position by controlling the exposure timing at initialization or start-up for fixing. ### Claim 15 An image forming apparatus comprising: a plurality of image forming units configured to form an image in different colors; a conveyance mechanism configured to convey a first pattern formed using at least a first image forming unit among the image forming units, that forms the image in a first color, and convey a second pattern formed using a second image forming unit among the image forming units, that forms the image in a second color; a detection unit configured to detect the first pattern conveyed by the conveyance mechanism and detecting the second pattern conveyed by the conveyance mechanism; a storage unit configured to store therein position adjustment information representing for which one of the first image and the second image position adjustment on a recording sheet has been performed, a first reference value as a reference value of a first time required after the image formation of the first pattern and before the detection of the first pattern by the detection unit, and a second reference value as a reference value of a second time required after the image formation of the second pattern and before the detection of the second pattern by the detection unit; and a control unit configured to control, when the position adjustment information represents that the position adjustment for the first image on the recording sheet has been performed, a timing of conveying the recording sheet to which the image formed by the first image forming unit is transferred on the basis of the first time and the first reference value and controlling a timing of conveying the recording sheet to which the image formed by the second image forming unit is transferred on the basis of the second time, the first reference value, and the second reference value, and the control unit configured to control, when the position adjustment information represents that the position adjustment for the second image on the recording sheet has been performed, a timing of conveying the recording sheet to which the image formed by the first image forming unit is transferred on the basis of the first time, the first reference value, and the second reference value and controlling a timing of conveying the recording sheet to which the image formed by the second image forming unit is transferred on the basis of the second time and the second reference value. ### Claim 16 (depends on 15) The image forming apparatus according to claim 15, wherein the control unit controls, when the position adjustment information represents that the position adjustment for the first image on the recording sheet has been performed, the timing of conveying the recording sheet to which the image formed by the first image forming unit is transferred on the basis of a difference between the first time and the first reference value and the timing of conveying the recording sheet to which the image formed by the second image forming unit is transferred on the basis of a value obtained by adding a value based on a difference between the second reference value and the first reference value to a value obtained based on a difference between the second time and the second reference value, and the control unit controls, when the position adjustment information represents that the position adjustment for the second image on the recording sheet has been performed, the timing of conveying the recording sheet to which the image formed by the first image forming unit is transferred on the basis of a value obtained by adding a value based on a difference between the first reference value and the second reference value to a value based on a difference between the first time and the first reference value and the timing of conveying the recording sheet to which the image formed by the second image forming unit is transferred on the basis of a difference between the second time and the second reference value. ### Claim 17 (depends on 15) The image forming apparatus according to claim 15, wherein the first color is a color other than black used in color image formation, the second color is a color other than black, the first image is a color image, the second image is a monochromatic image, the first image forming unit is an image forming unit located in the most upstream side of a conveying direction of the conveyance mechanism among the image forming units performing color image formation in the image forming units, and the second image forming unit is an image forming unit located in the most upstream side of a conveying direction of the conveyance mechanism among the image forming units performing monochromatic image formation in the image forming units. ### Claim 18 (depends on 17) The image forming apparatus according to claim 17, wherein the first pattern is formed using the image forming units performing color image formation among the image forming units, the second pattern is formed using the image forming unit performing monochromatic image formation among the image forming units, and the control unit controls an exposure timing for the color using a detection result of the first pattern from the detection unit, and controls an exposure timing for the monochrome using a detection result of the second pattern from the detection unit. ### Claim 19 (depends on 15) The image forming apparatus according to claim 15, wherein the position adjustment information represents that the position adjustment for the first image on the recording sheet has been performed. ### Claim 20 (depends on 15) The image forming apparatus according to claim 15, wherein the position adjustment is performed when the first reference value or the second reference value is updated.