| CPC G03G 21/203 (2013.01) [G03G 15/1665 (2013.01)] | 20 Claims |
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1. An image forming apparatus comprising:
a photosensitive drum;
a transfer member including at least a transfer roller or a transfer belt, a transfer nip being formed between the transfer member and the photosensitive drum, the transfer member being configured to transfer a toner image formed on the photosensitive drum to a sheet that passes through the transfer nip, the transfer member being configured to receive a transfer bias;
a humidity sensor configured to detect humidity;
a sheet sensor arranged upstream of the transfer member in a sheet conveyance direction, the sheet sensor being configured to detect a trailing end of the sheet; and
a controller configured to:
calculate a particular period, the particular period being different depending on the humidity detected by the humidity sensor;
apply a first transfer bias to the transfer member in a state where a toner image is being transferred to the sheet by the transfer member;
detect a first timing which is a timing of detecting the trailing end of the sheet by the sheet sensor; and
at a second timing which is the particular period after the first timing, change the transfer bias from the first transfer bias to a second transfer bias regardless of the humidity, the second transfer bias having a smaller absolute value than the first transfer bias, the second timing being a timing before the trailing end of the sheet exits the transfer nip, the second transfer bias being a bias that is applied to the transfer member when the trailing end of the sheet passes through the transfer nip.
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