An image forming apparatus includes a photosensitive drum, a development roller configured to supply developer to the photosensitive drum, a transfer roller configured to transfer a developer image formed on the photosensitive drum to a recording material, and a cleaning roller being in contact with the photosensitive drum, configured to clean a part of the recording material adhered to the photosensitive drum, wherein the diameter of the transfer roller is greater than the diameter of the development roller and the diameter of the cleaning roller is greater than the diameter of the development roller.

A cartridge detachably mountable to a main assembly of an image forming apparatus includes a photosensitive member unit including a photosensitive drum; a sheet configured to remove a deposited matter from a surface of the drum, the sheet being in contact with the surface of the drum at an end portion of the drum with respect to a rotational axis direction of the member; and a developing unit detachably mounted to the member unit, the developing unit including a developing roller configured to supply toner to the drum, and a storage portion configured to store the deposited matter removed from the surface of the drum by the sheet.

An image forming apparatus includes a photosensitive drum, a development roller configured to supply developer to the photosensitive drum, a transfer roller configured to transfer a developer image formed on the photosensitive drum to a recording material, and a cleaning roller being in contact with the photosensitive drum, configured to clean a part of the recording material adhered to the photosensitive drum, wherein the diameter of the transfer roller is greater than the diameter of the development roller and the diameter of the cleaning roller is greater than the diameter of the development roller.

A cartridge detachably mountable to a main assembly of an image forming apparatus includes a photosensitive member unit including a photosensitive drum; a sheet configured to remove a deposited matter from a surface of the drum, the sheet being in contact with the surface of the drum at an end portion of the drum with respect to a rotational axis direction of the member; and a developing unit detachably mounted to the member unit, the developing unit including a developing roller configured to supply toner to the drum, and a storage portion configured to store the deposited matter removed from the surface of the drum by the sheet.

A cartridge detachably mountable to a main assembly of an image forming apparatus includes a photosensitive member unit including a photosensitive drum; a sheet configured to remove a deposited matter from a surface of the drum, the sheet being in contact with the surface of the drum at an end portion of the drum with respect to a rotational axis direction of the member; and a developing unit detachably mounted to the member unit, the developing unit including a developing roller configured to supply toner to the drum, and a storage portion configured to store the deposited matter removed from the surface of the drum by the sheet.

An image forming apparatus resets a count value retained by a counter if a cleaning sequence is executed based on an execution instruction accepted from an operator via an operation unit or when the count value for counting the number of image-formed sheets reaches a predetermined value.

A cartridge detachably mountable to a main assembly of an image forming apparatus includes a photosensitive member unit including a photosensitive drum; a sheet configured to remove a deposited matter from a surface of the drum, the sheet being in contact with the surface of the drum at an end portion of the drum with respect to a rotational axis direction of the member; and a developing unit detachably mounted to the member unit, the developing unit including a developing roller configured to supply toner to the drum, and a storage portion configured to store the deposited matter removed from the surface of the drum by the sheet.

An image forming apparatus includes a detachable unit that is attachable to and detachable from an apparatus main body; and a cleaning unit that is provided in the apparatus main body, and at the time of attachment or detachment of the detachable unit, comes into contact with a grip portion of the detachable unit to clean a floating substance adhered to the grip portion, the floating substance being in the apparatus main body.

Provided is an inexpensive image forming apparatus capable of monitoring the generating state of various powders. The image forming apparatus includes a minute-particle-measuring device, a toner-particles-detecting air duct, a paper-dust-detecting air duct, and blower fans. The minute-particle-measuring device detects the concentration of minute particles in air. The toner-particle-detecting air duct is an air duct leading from the image forming unit to the minute-particle-measuring device. The paper-dust-detecting air duct is an air duct leading from the paper-conveying path to the minute-particle-measuring device. The blower fans are respectively provided in the toner-particle-detecting air duct and the paper-dust-detecting air duct, and generate airflow that flows toward the minute-particle-measuring device side. The blower fans in the toner-particle-detecting air duct and in the paper-dust-detecting air duct are switched.

An image forming apparatus including an image bearing member, a charging member, a developing roller, a transfer roller, and a brush configured to be brought into contact with a surface of the image bearing member on a side downstream of a transfer portion and upstream of a charging portion in a rotation direction of the image bearing member and in which, wherein, after the transfer of a developer image onto a transferred member, a developer remaining on the surface of the image bearing member is collected by the developing roller, the brush is disposed such that, in a cross section perpendicular to a rotation axis of the image bearing member, a contact region of the surface of the image bearing member in contact with the brush overlaps a virtual line containing the rotation axis of the image bearing member and extending upward from the rotation axis in a vertical direction.