An image forming apparatus includes an image carrier, a charging unit, an exposure unit, a developing unit, a transfer device, a sensor, and a processor. The processor compares a surface potential difference between a first surface potential and a second surface potential of the image carrier to a threshold to detect that a surface potential difference exceeding the threshold is generated in the image carrier in a state where the supply of the developer from the developing unit to the image carrier is inhibited, the first surface potential being a surface potential of the image carrier to which the transfer bias measured by the sensor is not applied, and the second surface potential being a surface potential of the image carrier to which the transfer bias is applied.

Provided is an image forming apparatus to and from which a replenishment container accommodating toner is attachable and detachable and which is configured to form a toner image on a recording material, the image forming apparatus including an image bearing member, a developer container, a developing bearing member, a replenishment port through which the developer container can be replenished with toner, a restriction member capable of transitioning to an allowance state in which a rotation of the replenishment container is allowed and to a restriction state in which the rotation of the replenishment container is restricted, a notification portion configured to notify a replenishment procedure for replenishing the developer container with toner from the replenishment container, and a controller configured to cause the notification portion to notify at least one step of the replenishment procedure.

The electrophotographic electroconductive member includes a support having an electroconductive outer surface, and an electroconductive layer on the surface of the support. The electroconductive layer has a matrix containing a crosslinked product of a first rubber, and domains dispersed in the matrix, and the domains each contain a crosslinked product of a second rubber and electroconductive particles. The matrix has a volume resistivity R1 of more than 1.0×10.sup.12 Ω.Math.cm, and the domains each have a volume resistivity R2 lower than the volume resistivity R1 of the matrix. The electroconductive layer further has a pore, and an inner wall of the pore is constituted by a part of the matrix and a part of the domains. The domains constituting the inner wall protrude into the pore at sites on the inner wall.

An apparatus includes an image bearing member, a developer container having a replenishment port, a developer bearing member, a detection portion configured to output remainder amount information corresponding to the amount of developer accommodated in the developer container, a notification portion capable of notifying a first state, and a second state, and a control portion, wherein the maximum amount of the developer that the developer container is capable of accommodating is larger than a value obtained by adding the amount of the developer accommodated in a replenishment container containing the developer for replenishment to the first amount, and wherein notification of the second state corresponds to notification of a case where the amount of the developer remaining in the developer container is larger than a case where the amount of the developer remaining in the developer container is the smallest.

Pressure-responsive particles include pressure-responsive base particles and resin particles, in which the pressure-responsive base particles contain a styrene-based resin that contains styrene and other vinyl monomers as polymerization components and a (meth)acrylic acid ester-based resin that contains at least two kinds of (meth)acrylic acid esters as polymerization components, a ratio of a mass of the (meth)acrylic acid esters to a total mass of polymerization components is 90% by mass or more in the (meth)acrylic acid ester-based resin, the pressure-responsive particles have at least two glass transition temperatures, a difference between a lowest glass transition temperature and a highest glass transition temperature is 30° C. or higher, and a ratio of a mass of the resin particles to a total mass of the pressure-responsive particles is 0.05% by mass or more and 2.0% by mass or less.

A sheet feeding device includes a feeding roller pair, a detecting portion, a first changing portion, a second changing portion, and a controller for controlling the first changing portion and the second changing portion. The controller starts a first feeding operation for feeding a sheet toward the obliquely feeding roller pair in a nipping state of the feeding roller pair and then starts a second feeding operation for feeding the sheet for abutting a side end of the sheet against the reference member in the nipping state of the obliquely feeding roller pair. The controller changes, after the first feeding operation is started and before the second feeding operation is started, a start timing of the second feeding operation on the basis of a detection result of a position of the side end of the sheet detected by the detecting portion.

An image formation apparatus includes: an image former that forms an image on a recording medium delivered along a predetermined delivery path and outputs the recording medium; a first hardware processor that judges whether or not the recording medium is an envelope; a second hardware processor that acquires a basis weight of the recording medium; a third hardware processor that determines control for when an image is formed on the recording medium on the basis of a judgment result from the first hardware processor and a basis weight acquired by the second hardware processor; and a fourth hardware processor that controls operation of the image former on the basis of a determination result from the third hardware processor.

An image forming apparatus according to the present invention includes an optical box, a housing having a discharge opening, a cover provided downstream of the optical box in a discharge direction in which a recording material is discharged through the discharge opening and forming a part of the housing, and a circuit board, wherein the circuit board includes a plurality of electronic components and a wiring board configured to electrically connect the plurality of electronic components, the circuit board is disposed in such a direction that a surface of the wiring board on which the plurality of electronic components is mounted intersects the discharge direction, and the wiring board is provided between the cover and the optical box in the discharge direction, and wherein, when viewed in a vertical direction, the optical box and the plurality of electronic components partially overlap each other.

An image forming apparatus includes an image forming portion, a sheet feeding portion, a first guiding member, a second guiding member, a driving portion, a detecting portion, and a controller. When a leading end of a sheet is detected by the detecting portion, in a case that information on a thickness of the sheet fed by the sheet feeding portion is a first thickness, the controller controls the driving portion so that a distance in a sheet feeding passage with respect to a thickness direction is a first distance, and in a case that the information on the thickness of the sheet fed by the sheet feeding portion is a second thickness thinner than the first thickness, the controller controls the driving portion so that the distance in the sheet feeding passage with respect to the thickness direction is a second distance shorter than the first distance.

Image forming apparatus includes a transfer nip control member being movable to a pressing position where a pressing force for positioning a transfer roller in a transfer nip releasing position is applied to a transfer unit in a closed position and to a releasing position where application of the pressing force is released; a fixing nip control mechanism for changing a relative position between a fixing roller and an opposing member to a fixing position where a fixing nip is formed and to a fixing nip releasing position; and an interlocking mechanism for moving the transfer nip control member in the releasing position to the pressing position in conjunction with a fixing nip releasing operation by the fixing nip control mechanism. The transfer nip control member in the pressing position is moved to the releasing position when the transfer unit is moved from the closed position to an open position.