| CPC G03G 15/1615 (2013.01) [G03G 2215/00156 (2013.01); G03G 2215/1623 (2013.01)] | 6 Claims |
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1. An image forming apparatus comprising:
an image forming portion configured to form a toner image;
a rotatable intermediary transfer belt onto which the toner image formed by said image forming portion is transferred;
an inner roller contacting an inner peripheral surface of said intermediary transfer belt and configured to stretch said intermediary transfer belt;
a transfer unit contactable to an outer peripheral surface of said intermediary transfer belt and configured to form a transfer nip, where the toner image is transferred from said intermediary transfer belt onto a recording material, by nipping said intermediary transfer belt between said transfer unit and said inner roller, said transfer unit including an outer roller configured to form the transfer nip between said outer roller and said inner roller;
a contact and separation mechanism configured to bring said transfer unit into contact with and separation from said intermediary transfer belt;
a changing mechanism capable of changing a position of the transfer nip with respect to a circumferential direction of said inner roller by changing a position of said inner roller, relative to said outer roller,
wherein said changing mechanism is capable of changing the position of said inner roller to a first position where the position of the transfer nip corresponds to a first transfer position and to a second position where the position of the transfer nip corresponds to a second transfer position;
a driving device configured to drive said intermediary transfer belt; and
a controller configured to control said changing mechanism and said contact and separation mechanism,
wherein in a case that a mode in which the position of said inner roller is changed by said changing mechanism in a period after trailing end of a preceding recording material reaches through the transfer nip and before leading edge of a recording material subsequent to the preceding recording material reaches the transfer nip during execution of a continuous image forming job for forming and outputting images on a plurality of recording materials, is executed,
in the period, said controller controls:
(i) said contact and separation mechanism and said changing mechanism so that a separating operation for separating said transfer unit from said intermediary transfer belt and a moving operation for moving said inner roller to a position corresponding to a position of a time of transfer of the recording material subsequent to the preceding recording material, and then
(ii) said contact and separation mechanism so that said transfer unit is contacted to said intermediary transfer belt, and then
(iii) an image forming operation so that formation of a latent image on the recording material subsequent to the preceding recording material is started after contact of said transfer unit to said intermediary transfer belt is completed.
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