An image forming apparatus includes an image carrier that carries a latent image, a developer holder that holds developer for developing the latent image carried by the image carrier, and a layer-thickness restriction member that restricts the layer thickness of the developer held by the developer holder. When the developer holder approaches the layer-thickness restriction member, the layer-thickness restriction member moves away from the developer holder and then toward the developer holder.

An image forming apparatus includes: a photoconductor drum; a developing device having a plurality of developer rollers and supplying toner to the photoconductor drum; a first pressing force applier that applies a force to the developing device to press the plurality of developer rollers toward the photoconductor drum; and a second pressing force applier that flexibly holds the developing device in a vertical direction.

A developing cartridge may include a developing roller and a casing capable of containing a developer material, a member having a first end portion and a second end portion, the member being movable together with the casing and the developing roller, and the member having a first hole extending in a direction between the first end portion and the second end portion; and a first lever movable relative to the casing between a first position and a second position, the first lever including one end portion that functions as the point of effort, an other end portion that functions as the point of application, and a cam surface that is located between the one end portion and the other end portion and that functions as a pivot point.

An image forming apparatus may include a photosensitive member, a developing device including a developing roller, pressing members configured to engage with the developing device and springs configured to urge the pressing members. In some examples, each of the pressing members may be configured to contact and move the developing device between various positions based on the urging of the springs. Additionally or alternatively, various ends of a contact surface of the developing roller configured to contact developer may be disposed relative to an axis line of the developing roller and pressing surfaces of the pressing members.

An image forming apparatus capable of forming images in mono-color and a plurality of colors includes first and second image forming units and a control unit. The image forming unit includes a rotatable image bearing member, a rotatable developing member that contacts the image bearing member to supply a developer to the surface thereof, and a developer supply member that supplies the developer to the developing member. The control unit switches between an image forming operation of forming an image on the image bearing member surface and a cleaning operation of removing an attached matter on the image bearing member surface with the developing member by controlling a voltage applied to the developing member and a voltage applied to the developer supply member.

An image forming apparatus capable of detecting a development nip disengaging error and a method of detecting a development nip disengaging error are provided. According to an example method, a test pattern is formed on a photoconductor of an image forming apparatus, the test pattern transferred to an intermediate transfer belt is detected through a sensor from a time when an operation of an adjusting member moving a developing roller is controlled such that the developing roller moves from a disengaging position where the developing roller is spaced from the photoconductor to disengage a development nip from the photoconductor to a developing position where the developing roller is in contact with the photoconductor to form the development nip, and whether the development nip disengaging error occurred is determined based on the detected test pattern.

An image forming apparatus may include a photosensitive member, a developing device including a developing roller, pressing members configured to engage with the developing device and springs configured to urge the pressing members. In some examples, each of the pressing members may be configured to contact and move the developing device between various positions based on the urging of the springs. Additionally or alternatively, various ends of a contact surface of the developing roller configured to contact developer may be disposed relative to an axis line of the developing roller and pressing surfaces of the pressing members.

A process cartridge detachably mountable in an image forming apparatus includes a toner cartridge for accommodating a developer; a developer roller; and a driving force receiving assembly for receiving a driving force of the image forming apparatus and driving the developer roller to rotate; and further includes a first stopper and a second stopper provided at a bottom of the toner cartridge, and the first stopper and the second stopper being movable relative to the toner cartridge in a direction perpendicular to an axial direction of the driving force receiving assembly; and when the first stopper and/or the second stopper move, a driving force receiving head of the driving force receiving assembly is movable in an axial direction of the driving force receiving assembly. The process cartridge can realize separation and contact between a developer roller and an image forming apparatus.

A developing unit includes an elastic member that is disposed nearer a middle portion in a rotational axis direction in relation to an edge portion seal member disposed between a developing roller and a developer container, in an edge portion of a regulation member in a rotational axis direction, and contacts a confronting surface at a side opposite to a contact portion in a developing blade, wherein the developing roller, the developing blade, and the elastic member are arranged so as to make contact with one another in sequence in a normal direction in the contact portion of the developing roller.

Measures for controlling an engagement force between a photo imaging plate (110) and a developer roller (200) in a printing device (100) are described. A motor (310) is operated to generate rotational motion. The rotational motion is translated into linear motion. The linear motion causes an adjustment to the engagement force between the developer roller and the photo imaging plate. A characteristic of the motor is monitored. The motor is controlled on the basis of the monitored characteristic in order to maintain a desired engagement force between the developer roller and the photo imaging plate.