# US 2014/0153945 A1 · Image forming apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0153945 A1 - Document ID: US20140153945A1 - Status: Published application - Kind: A1 - Application number: 13/920,438 - Filed: 2013-06-18 - Published: 2014-06-05 - Earliest claimed: 2012-11-30 - Assignees: Fuji Xerox Co., Ltd. - Applicants: Fuji Xerox Co., Ltd. - Inventors: Tomoaki YOSHIOKA - Web page: https://patentgrep.com/patent/US20140153945A1 ## CPC - G03G 15/1615: {relating to the driving mechanism for the intermediate support, e.g. gears, couplings, belt tensioning} - G03G 15/0136: {transfer member separable from recording member or vice versa, mode switching} - G03G 21/168: {for the transfer unit} - G03G 2215/0129: horizontal medium transport path at the secondary transfer - G03G 2215/0193: transfer member separable from recording member - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract An image forming apparatus includes plural image carriers, an intermediate transfer body, a contact and separation mechanism, a selection member, plural first transfer units, a second transfer unit, and an adjustment member. Each image carrier carries a toner image. The intermediate transfer body is disposed so as to be in contact with one or more image carriers. The contact and separation mechanism causes the intermediate transfer body to be in contact with or separated from the image carriers. The selection member selects a first contact state or a second contact state. Each first transfer unit forms a transfer electric field in a first transfer region to transfer a toner image onto the intermediate transfer body. The second transfer unit forms a transfer electric field in a second transfer region to transfer toner images onto a recording material. The adjustment member adjusts first transfer conditions. ## Claims ### Claim 1 An image forming apparatus comprising: a plurality of image carriers each of which carries a toner image that is formed thereon; an intermediate transfer body that is rotated while facing the image carriers, is disposed so as to be in contact with one or more image carriers among the image carriers, and carries one or more toner images formed on the one or more image carriers; a contact and separation mechanism that causes the intermediate transfer body to be in contact with or separated from the image carriers; a selection member that selects, using the contact and separation mechanism, a first contact state in which all of the image carriers and the intermediate transfer body are in contact with each other or a second contact state in which one or some of the image carriers and the intermediate transfer body are in contact with each other; a plurality of first transfer units each of which includes a transfer member that corresponds to one image carrier among the image carriers and that is in contact with a back surface of the intermediate transfer body, and each of which forms a transfer electric field in a first transfer region between the transfer member and the one image carrier to transfer a toner image onto the intermediate transfer body; a second transfer unit that includes a transfer member disposed so as to face the intermediate transfer body and that forms an electric field in a second transfer region between the transfer member and the intermediate transfer body to transfer toner images that have been transferred onto the intermediate transfer body onto a recording material; and an adjustment member that adjusts first transfer conditions for the first transfer units, wherein the adjustment member includes a load adjustment unit that adjusts, in a case where the selection member selects the second contact state, for the first transfer unit corresponding to the image carrier located at the most downstream position in a movement direction of the intermediate transfer body among the one or more image carriers used for image formation, a load in the first transfer region of the transfer member that is in contact with the intermediate transfer body so that the load is set to be higher than in a case where the first contact state is selected, and so that, in a case where there is a first transfer unit located on an upstream side in the movement direction of the intermediate transfer body, the load is set to be higher than a load in the first transfer unit. ### Claim 2 (depends on 1) The image forming apparatus according to claim 1, wherein the adjustment member includes a load adjustment unit that adjusts, in a case where the selection member selects the second contact state, for the first transfer unit corresponding to an image carrier other than the image carrier located at the most downstream position in the movement direction of the intermediate transfer body among the one or more image carriers used for image formation, a load in the first transfer region of the transfer member that is in contact with the intermediate transfer body so that the load is set to be equal to or higher than in a case where the first contact state is selected. ### Claim 3 (depends on 1) The image forming apparatus according to claim 1, wherein the adjustment member includes an electric field adjustment unit that adjusts, in a case where the selection member selects the second contact state, for the first transfer unit corresponding to the image carrier located at the most downstream position in the movement direction of the intermediate transfer body among the one or more image carriers used for image formation, a transfer electric field that acts on the first transfer region of the transfer member of the first transfer unit so that the transfer electric field is set to be lower than in a case where the first contact state is selected, and so that, in a case where there is a first transfer unit located on an upstream side in the movement direction of the intermediate transfer body, the transfer electric field is set to be lower than a transfer electric field in the first transfer unit. ### Claim 4 (depends on 2) The image forming apparatus according to claim 2, wherein the adjustment member includes an electric field adjustment unit that adjusts, in a case where the selection member selects the second contact state, for the first transfer unit corresponding to the image carrier located at the most downstream position in the movement direction of the intermediate transfer body among the one or more image carriers used for image formation, a transfer electric field that acts on the first transfer region of the transfer member of the first transfer unit so that the transfer electric field is set to be lower than in a case where the first contact state is selected, and so that, in a case where there is a first transfer unit located on an upstream side in the movement direction of the intermediate transfer body, the transfer electric field is set to be lower than a transfer electric field in the first transfer unit. ### Claim 5 (depends on 3) The image forming apparatus according to claim 3, wherein the adjustment member includes an electric field adjustment unit that adjusts, in a case where the selection member selects the second contact state, for the first transfer unit corresponding to an image carrier other than the image carrier located at the most downstream position in the movement direction of the intermediate transfer body among the one or more image carriers used for image formation, a transfer electric field that acts on the first transfer region of the transfer member of the first transfer unit so that the transfer electric field is set to be equal to or lower than in a case where the first contact state is selected. ### Claim 6 (depends on 4) The image forming apparatus according to claim 4, wherein the adjustment member includes an electric field adjustment unit that adjusts, in a case where the selection member selects the second contact state, for the first transfer unit corresponding to an image carrier other than the image carrier located at the most downstream position in the movement direction of the intermediate transfer body among the one or more image carriers used for image formation, a transfer electric field that acts on the first transfer region of the transfer member of the first transfer unit so that the transfer electric field is set to be equal to or lower than in a case where the first contact state is selected. ### Claim 7 (depends on 3) The image forming apparatus according to claim 3, further comprising: a resistance measurement device that is capable of measuring a combined resistance in the second transfer region of the second transfer unit, wherein the adjustment member includes an electric field adjustment unit that adjusts, for one or more first transfer units corresponding to the one or more image carriers used for image formation, in accordance with the combined resistance in the second transfer region measured by the resistance measurement device, a transfer electric field that acts on the first transfer region of the transfer member that is in contact with the intermediate transfer body so that the transfer electric field becomes higher when the combined resistance is changed to be decreased. ### Claim 8 (depends on 4) The image forming apparatus according to claim 4, further comprising: a resistance measurement device that is capable of measuring a combined resistance in the second transfer region of the second transfer unit, wherein the adjustment member includes an electric field adjustment unit that adjusts, for one or more first transfer units corresponding to the one or more image carriers used for image formation, in accordance with the combined resistance in the second transfer region measured by the resistance measurement device, a transfer electric field that acts on the first transfer region of the transfer member that is in contact with the intermediate transfer body so that the transfer electric field becomes higher when the combined resistance is changed to be decreased. ### Claim 9 (depends on 5) The image forming apparatus according to claim 5, further comprising: a resistance measurement device that is capable of measuring a combined resistance in the second transfer region of the second transfer unit, wherein the adjustment member includes an electric field adjustment unit that adjusts, for one or more first transfer units corresponding to the one or more image carriers used for image formation, in accordance with the combined resistance in the second transfer region measured by the resistance measurement device, a transfer electric field that acts on the first transfer region of the transfer member that is in contact with the intermediate transfer body so that the transfer electric field becomes higher when the combined resistance is changed to be decreased. ### Claim 10 (depends on 6) The image forming apparatus according to claim 6, further comprising: a resistance measurement device that is capable of measuring a combined resistance in the second transfer region of the second transfer unit, wherein the adjustment member includes an electric field adjustment unit that adjusts, for one or more first transfer units corresponding to the one or more image carriers used for image formation, in accordance with the combined resistance in the second transfer region measured by the resistance measurement device, a transfer electric field that acts on the first transfer region of the transfer member that is in contact with the intermediate transfer body so that the transfer electric field becomes higher when the combined resistance is changed to be decreased.