Image forming apparatus

摘要

An image forming apparatus includes: a first image forming unit including a first transfer unit forming a first nip with a first photosensitive drum for black; a second image forming unit including a second transfer unit forming a second nip with a second photosensitive drum for a color; and a control device which, when a first sheet and a second sheet are continuously conveyed in corresponding order by the conveyance belt at the monochrome mode, is configured to supply a first transfer current for a first time period during which the first sheet or the second sheet pass through the second nip and supply a second transfer current, which is smaller than the first transfer current, for a second time period that is a sheet interval between the first sheet and the second sheet.

主权项

1. An image forming apparatus comprising:
a conveyance belt configured to convey a sheet; a first image forming unit configured to form a monochrome image in a monochrome mode, and comprising:
a first photosensitive drum for black; anda first transfer unit configured to nip the conveyance belt with the first photosensitive drum so as to form a first nip; a second image forming unit configured to form a color image in a color mode, and comprising:
a second photosensitive drum for a color other than black; anda second transfer unit configured to nip the conveyance belt with the second photosensitive drum so as to form a second nip; and a control device configured to control a transfer current flowing to the second nip, wherein the control device is configured to, when a first sheet and a second sheet are continuously conveyed in corresponding order by the conveyance belt in the monochrome mode:
supply a first transfer current for a first time period during which the first sheet or the second sheet pass through the second nip; andsupply a second transfer current, which is smaller than the first transfer current, for a second time period that is a time interval between the first sheet and the second sheet, and wherein the control device is further configured to supply a third transfer current that is larger than the first transfer current for the first time period when the first sheet and the second sheet are continuously conveyed in corresponding order by the conveyance belt in the color mode.