An image forming apparatus includes a rotatable image bearing member, a developing member, a transfer member, and a brush contacting a surface of the image bearing member in a contact portion downstream of a transfer portion and upstream of a developing portion with respect to a rotational direction of the image bearing member. The toner which is not transferred onto a toner image receiving member is collected by the developing member. In a charging series, the toner is positioned on the same side as a normal charge polarity of the toner relative to the brush. In the contact portion, a maximum value of a contact pressure of 0.7 gf/mm.sup.2 or more and 3.5 gf/mm.sup.2 or less, a maximum contact area ratio is 18% or more and 74% or less, and a Clark-Evans index of the brush is 1 or more.

An image forming apparatus includes a transfer unit and a pair of measuring units. The transfer unit transfers an image onto at least one recording medium by applying a voltage between the at least one recording medium and the image along a thickness direction of the at least one recording medium. Before the transfer unit applies the voltage, the pair of measuring units measure respective electrical resistance values of a front surface and a rear surface of the at least one recording medium in a direction crossing the thickness direction.

According to the present invention, increase in a dynamic friction force can be suppressed and cleaning performance of a cleaning member can be improved under any operating environment without additionally providing a special mechanism. An intermediate transfer member includes a substrate layer and a surface layer, the surface layer contains a cured product of a polymerizable monomer, and the monomer contains a compound represented by the following formula (1):

A-[(L-B).sub.k-D].sub.m(D).sub.l  (1) wherein A represents a tetra- or higher-valent organic group, B independently represents an alkylene oxide group having 4 to 15 carbon atoms, D independently represents a (meth)acryloyl group, L independently represents —(CO)— or a single bond, k independently represents an integer of 1 or more, l represents an integer of 0 to 3, m represents an integer of 2 or more, and a sum of l and m represents an integer of 3 or more.

A sheet transfer guide, which is disposed along a sheet conveyance passage through which a sheet passes, provided to guide the sheet, and is included in an image forming apparatus and an image reading device, includes a base material, a coat layer formed on the base material and having a surface roughness smaller than a surface roughness of the base material, and a guide face to which the sheet contacts. The coat layer is formed on the guide face.

An image forming apparatus includes an image bearing member, an intermediary transfer member having ion conductivity and a rotatable endless belt shape, a primary transfer member, a secondary transfer member, a cleaning member, an environment sensor and a controller. Based on a result of the environment sensor, the controller controls so as to change a current balance based on an integrated value of a first current value and an integrated value of a second current value. The first current value is a current flowing from inside of the intermediary transfer member to outside thereof and the second current value is a current flowing from outside of the intermediary transfer member to inside thereof.

An image forming apparatus includes a chassis having an opening, a cover, photosensitive members, an intermediate transfer belt, a primary-transfer member, a secondary-transfer roller, a cleaner device, an external-sheet inlet, a waste toner container, a connector, and a conveying roller, which is arranged within the feeding path to feed the recording sheet inserted through the external-sheet inlet in the feeding path. The conveying roller is mounted on the waste toner container and removable from the chassis along with the waste toner container.

An image forming apparatus has an image carrier carrying a toner image; a transfer member made with an ion conductive material and forming a transfer nip by being pressed by the image carrier; and a power supply continuously applying a transfer bias voltage to the transfer member as a plurality of print media pass through the transfer nip. The transfer bias voltage has a predetermined polarity. A control section determines whether the resistance of a nip-margin area has exceeded a predetermined resistance threshold, the nip-margin area being a marginal portion of the transfer nip through which no print medium passes. When the determination of the control section is affirmative, the power supply applies a reverse-bias voltage to the transfer member, the reverse-bias voltage having an opposite polarity to the transfer bias voltage.

An image forming apparatus that includes an image bearing member which can bear a toner image, a transfer member used to transfer a toner image onto a recording material from the image bearing member, and a reading device which reads density information of images on recording material disposed on a platen. The image forming apparatus forms a first chart on a first recording material and a second chart on a second recording material by sequentially transferring a plurality of test images while applying a plurality of test voltages to the transfer member. The two charts are read by the reading device and the transfer voltage is adjusted based on the reading result.

An image forming apparatus includes: an annular transfer belt to which an image is transferred; a transfer roller that transfers an image to a recording medium when the recording medium passes through a transfer area formed between the transfer roller and the transfer belt; a drive mechanism that causes the transfer roller to rotate; and a speed adjustment mechanism that adjusts a rotational speed of the transfer roller achieved by the drive mechanism in units of a cycle of the transfer roller, and switches between a first adjustment pattern and a second adjustment pattern to execute switched adjustment pattern in a cycle including a state in which the transfer roller transports the recording medium, the first adjustment pattern for adjusting the rotational speed of the transfer roller, the second adjustment pattern for adjusting the rotational speed of the transfer roller with a pattern different from the first adjustment pattern.

An image forming apparatus forms an image on a recording material and includes an apparatus body, a first process cartridge including a first photosensitive member and a first developing roller to supply first toner to the first photosensitive member, with the first process cartridge being detachably attached to the apparatus body, and a toner cartridge to accommodate the first toner and detachably attached to the apparatus body independently from the first process cartridge. A second process cartridge includes a second photosensitive member and a second developing roller to supply second toner to the second photosensitive member, with the second process cartridge being detachably attached to the apparatus body and configured not to be replenished with the second toner in a state where the second process cartridge is attached to the apparatus body.