An image forming apparatus controls the number of rotations of a photosensitive drum based on information related to the use of the photosensitive drum and a suspension time in a rotation operation of rotating the photosensitive drum after a lapse of the suspension time between a first image forming operation of forming an image on a transfer material and a second image forming operation performed after the first image forming operation.

Provided is a toner transfer device including: a carrier device that includes a surface on which a charged toner is carried; an electrode that attracts the toner from the surface of the carrier device; a conveyance path of a print medium which is formed between the carrier device and the electrode; and a power supply device that causes a potential difference to occur between the carrier device and the electrode to transfer the toner from the carrier device onto the print medium when the print medium is located in the conveyance path.

An image forming apparatus includes an image bearing member, a transfer member, an acquiring portion, an applying portion, and a controller. When a transfer voltage is subjected to constant-voltage control so that the transfer voltage applied to the transfer member by the applying portion is substantially constant, in a case that the transfer voltage when a toner amount used for a toner image is a first toner amount is a first voltage, the controller controls the applying portion so that the transfer voltage is a second voltage smaller in absolute value than the first voltage in a case that the toner amount is a second toner amount larger than the first toner amount. The acquiring portion acquires toner amount information on the toner amount for each toner image transferred onto a single recording material.

A printing system includes a printing unit, an operation unit, and a control unit. The printing unit prints an image on a sheet, conveys the sheet to a reading unit, and performs adjustment for printing an image on the sheet based on an image read by the reading unit. The control unit performs an operation of controlling to execute a manual adjustment function for adjusting predetermined adjustment items based on adjustment values received via the operation unit after authentication of an operator. The control unit performs another operation of controlling to execute an automatic adjustment function for adjusting the predetermined adjustment items based on the image read by the reading unit without the authentication of the operator.

An image forming apparatus includes an image forming portion, a transfer unit, a power supply, and a reader. A test chart is formed by transferring test images to a recording material while applying test voltages from the power supply to the transfer unit. A transfer voltage to be applied to the transfer unit during transfer is set based on the read test images. A reference image is formed on the test chart. The reader reads the test chart by scanning the test chart from a first position to a second position that falls within the test images. The first position falls within a boundary of the recording material on which the test chart is formed and falls outside the test images. Based on the reference image, the result of the reader reading the test chart is obtained by scanning the test chart from the first position to the second position.

A printing system includes a printing unit configured to print an image on a sheet, a receiving unit configured to receive an adjustment value from a user, first and second adjustment units, and a control unit. The first adjustment unit conveys the sheet on which the image is printed by the printing unit to a reading apparatus, and performs a first adjustment based on an image read by the reading apparatus. The second adjustment unit performs a second adjustment based on the adjustment value received by the receiving unit. The control unit prevents the first adjustment from being performed for a sheet of a size where the first adjustment is not properly performed among sheets for the printing unit to print an image on. The control unit does not prevent the second adjustment from being performed for the sheet of the size where the first adjustment is not properly performed.

An image forming apparatus includes an image forming portion, a transfer portion, a power source, a reading portion, and a controller. The controller executes an output operation so that first test images do not overlap with second test images, respectively, on a first side and a second side of a recording material. On the basis of information on the second test voltage for transfer of the second test image, of the plurality of second test images, of which information on a density read by the reading portion coincides with a preset condition, the controller sets a transfer voltage for image transfer onto the second side in double-side image formation so that an absolute value of the transfer voltage set for the image transfer onto the second side in the double-side image formation is larger than an absolute value of the second test voltage coincided with the preset condition.

An image forming apparatus comprising includes an image carrying member including a movable surface to include a toner image; a transfer roller to form a transfer nip between the transfer roller and the movable surface of the image carrying member, to move position in a direction in correspondence to a thickness of a print medium to intersect a direction of introduction of the print medium into the transfer nip, and to receive a transfer bias voltage to transfer the toner image from the movable surface of the image carrying member to the print medium; and a movement guide structure to guide the print medium toward the transfer nip, and to move in synchronization with the movement of the position of the transfer roller to change a gap between an end of the movement guide structure facing the image carrying member and the image carrying member.

An image forming apparatus includes a rotatable photosensitive member, a charging member, an exposure unit, a developing member, a developing voltage applying portion, a transfer member, a first transfer voltage applying portion, a second transfer voltage applying portion, a common power source, and a controller. The controller carries out control so as to execute an image forming operation, and a non-image forming operation and so as to execute, as the non-image forming operation, a cleaning operation. The controller controls a change in output of the common power source so that a value of a voltage applied from the developing voltage applying portion to the developing member during the cleaning operation is made different from a value of a voltage applied from the developing voltage applying portion to the developing member during formation of the toner image.

An image forming apparatus includes an image carrier, a charging device, a developing device, a transfer device, a development power supply, a current measurement device, and a processor. The development power supply applies a predetermined bias voltage to the developing device. The processor functions as a calculator and a controller. The calculator calculates a surface potential of the image carrier based on the development current measured by the current measurement device. The controller controls the charging device, the developing device, the transfer device, and the development power supply. The controller sets a tentative transfer current to be flowed through the transfer device while the calculator calculates the surface potential.