Abstract: A toner pattern is detected by a color misregistration detection sensor to detect a duration of contact between a development roller and a photosensitive drum. A contact/separation motor for driving the development roller is accelerated or decelerated based on the detected duration of contact between the development roller and the photosensitive drum. This control enables shortening the duration of contact between the development roller and the photosensitive drum, thus reducing the shortening of their lifetime.

Abstract: In an electrophotographic image forming apparatus employing a contact development system, contact of a development roller 64 against a photosensitive drum 61 is started while forming an electrostatic latent image of a detection pattern 81 for detection in each individual apparatus, and a developed toner image is detected at a predetermined position. At this time, a time as from the time when contact of the development roller 64 was started until the time when the toner image was detected is measured, and a delay time Xs from a time (t11) when contact operation of the development roller 64 was started until a time (t131) of actual contact is calculated by subtracting the time needed until the developed toner image reaches the detection position. The time when contact of the development roller 64 is started is delayed by this time. The same sort of control is also performed for the separation time.

Abstract: A cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus. The apparatus includes movable first and second engageable members. The cartridge includes an electrophotographic photosensitive drum, a developing roller, a first force receiving portion for receiving, from the first engageable member, a force for separating the drum and roller, a second force receiving portion for keeping the drum and roller spaced from each other and for receiving a force, from the second engageable member, for separating the first engageable member and the first force receiving portion. When the cartridge is transported while being in a mounted state, the second force receiving portion receives a force for separating the first engageable member and the first force receiving portion from each other from the second engageable member.

Abstract: An image forming apparatus includes a photosensitive drum, an optical unit provided below the photosensitive drum and including a cover glass for transmitting light emitted toward the photosensitive drum, and a cleaning member configured to clean a surface of the cover glass. The cleaning member includes a cleaning sheet configured to move foreign substances on the surface, and a wiping member configured to wipe foreign substances from the surface. The cleaning sheet and the wiping member move in contact with the surface of the cover glass when the cleaning member cleans the surface. The wiping member moves in contact with a portion of the surface of the cover glass after the cleaning sheet moves in contact with the portion. Accordingly, the cover glass can be reliably cleaned even when an unexpectedly large number of foreign substances that vary in particle size and shape adhere to the cover glass.

Abstract: A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus. The apparatus includes a movable first engageable member and a movable second engageable member. The cartridge includes an electrophotographic photosensitive drum, a developing roller, a first frame supporting the drum, a second frame supporting the roller, a first force receiving portion for receiving, from the first engageable member, a force for separating the drum and roller a second force receiving portion for keeping the drum and roller spaced from each other and for receiving a force, from the second engageable member, for separating the first engageable member and the first force receiving portion. When the cartridge is transported while being in a mounted state, the second force receiving portion receives a force for separating the first engageable member and the first force receiving portion from each other from the second engageable member.