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 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.

A process cartridge includes an image bearer, a developer bearer, and a positioning member. The image bearer is rotatable. The developer bearer is rotatable and opposite to the image bearer. The positioning member determines an opposing distance between the image bearer and the developer bearer, and includes a fitting portion and a groove. A fitted portion of the image bearer rotatably fits to the fitting portion. The groove extends from a ceiling portion to a bottom portion. A shaft portion of the developer bearer is slidingly movable in the groove. The groove is formed such that the shaft portion of the developer bearer contacts the bottom portion and is supported by the bottom portion. The ceiling portion of the groove is open upward so that the shaft portion of the developer bearer is insertable to and removable from the groove.

A controller is configured to, when forming an image on one sheet, in a case where a length of one sheet in a conveyance direction is larger than a first length, drive a moving mechanism to move a plurality of developing rollers from a separation position to a contact position, temporarily stop driving of the moving mechanism, and then, at a first timing, again drive the moving mechanism to move the plurality of developing rollers from the contact position to the separation position; and in a case where the length of the one sheet in the conveyance direction is smaller than or equal to the first length, drive the moving mechanism to move the plurality of developing rollers from the separation position to the contact position and then to move the plurality of developing rollers from the contact position to the separation position without stopping driving of the moving mechanism.

A developing device includes a developer container, a developing roller, and a doctor member. The developer container contains a developer including a toner and a developer. The developing roller includes a developing sleeve bearing the developer, a magnet roller in the developing sleeve. The doctor member includes a regulating portion regulating an amount of the developer home on the developing sleeve to be a predetermined amount. The regulating portion is disposed with a first distance from the developing sleeve. The developing sleeve is disposed with a second distance from an image hearer, and when the developing sleeve bearing the predetermined amount of developer passes a vicinity of the image bearer, a value obtained by dividing the predetermined amount by the second distance is less than a threshold of occurrence of adherence of the developer to the developing sleeve.

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.

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.

A developing device includes a developer container, a developing roller, and a doctor member. The developer container contains a developer including a toner and a developer. The developing roller includes a developing sleeve bearing the developer, a magnet roller in the developing sleeve. The doctor member includes a regulating portion regulating an amount of the developer home on the developing sleeve to be a predetermined amount. The regulating portion is disposed with a first distance from the developing sleeve. The developing sleeve is disposed with a second distance from an image hearer, and when the developing sleeve bearing the predetermined amount of developer passes a vicinity of the image bearer, a value obtained by dividing the predetermined amount by the second distance is less than a threshold of occurrence of adherence of the developer to the developing sleeve.

An image forming apparatus includes an image carrier, a toner supply unit, an application roller adjacent to the image carrier, a toner measuring unit, and a control unit. The toner supply unit supplies toner to the image carrier. The application roller applies a lubricant to the image carrier. The toner measuring unit measures an amount of toner transferred from the image carrier to the application roller. The control unit adjusts the supply of toner to be supplied to the image carrier in accordance with the amount of toner measured by the toner measuring unit.

A measuring device that measures a distance between a first measurement target and a second measurement target. The measuring device includes a CPU that: calculates a first surface shape of the first measurement target based on first measurement data acquired from a first line sensor that emits first laser light to the first measurement target, and calculates a second surface shape of the second measurement target based on second measurement data acquired from a second line sensor that emits second laser light to the second measurement target; transforms at least one of a first coordinate system of the first line sensor and a second coordinate system of the second line sensor, to form a unified coordinate system; and calculates a distance between the first measurement target and the second measurement target in the unified coordinate system.