Image forming apparatus with developing roller separation processing

An image forming apparatus comprising:

• a photosensitive drum;
• a developing roller configured to move between a contact position at which the developing roller contacts the photosensitive drum and a separation position at which the developing roller is separated from the photosensitive drum;
• a transfer member configured to form a transfer nip with the photosensitive drum;
• a moving mechanism configured to move the developing roller between the contact position and the separation position;
• a drive mechanism configured to drive the photosensitive drum;
• and
• a controller configured to:
• in a case where an inter-sheet time is shorter than or equal to a first time, maintain the developing roller in contact with the photosensitive drum during the inter-sheet time, the inter-sheet time being a time after a trailing end of a sheet corresponding to a particular page reaches the transfer nip and before a leading end of a sheet corresponding to a next page reaches the transfer nip in a case where a plurality of pages is printed successively;
• in a case where the inter-sheet time is longer than the first time and shorter than or equal to a second time longer than the first time, perform at least part of temporary separation processing during the inter-sheet time, the temporary separation processing being processing of controlling, in a state where the photosensitive drum is rotating, the moving mechanism and the drive mechanism to separate the developing roller from the photosensitive drum and subsequently bring the developing roller into contact with the photosensitive drum;
• in a case where the inter-sheet time is longer than the second time, perform at least part of temporary stop processing during the inter-sheet time, the temporary stop processing being processing of controlling the moving mechanism and the drive mechanism to separate the developing roller from the photosensitive drum and then stop rotation of the photosensitive drum, and subsequently restart rotation of the photosensitive drum and then bring the developing roller into contact with the photosensitive drum;
• and
• perform duplex print processing of performing printing on both sides of a sheet,
• wherein the inter-sheet time is set depending on a page interval in the duplex print processing;
• and
• wherein the controller is configured to:
• when performing the duplex print processing on only one sheet, perform the temporary stop processing during the inter-sheet time between each page;
• when performing the duplex print processing on two sheets, perform the temporary separation processing during the inter-sheet time between each page;
• and
• when performing the duplex print processing on three or more sheets, perform the temporary separation processing or maintain the developing roller in contact with the photosensitive drum during the inter-sheet time between each page.