Abstract: An image forming apparatus allows mounting thereon and dismounting therefrom a plurality of types of cartridges, each of the cartridges including a plurality of process members used for image formation and a storage medium for storing information. The image forming apparatus includes a storage unit that stores a plurality of pieces of setting information for setting an image forming condition in accordance with a plurality of characteristics of the cartridges; and a controller that sets the image forming condition based on information regarding a usage amount of each of the plurality of types of cartridges and selection information for selecting one of the plurality of pieces of setting information, the selection information being stored in the storage medium in the cartridge.

Abstract: A lens apparatus includes a movable optical member, a position detection unit for detecting a position of the movable optical member, a control unit for recognizing position information obtained by the position detection unit and controlling driving of the movable optical member, and a signal input/output unit for synthesizing virtual and photographed pictures. The signal input/output unit can transmit the position information from the position detection unit linked with the movable optical member by three methods based on an analog voltage signal, a digital pulse train and data communication from the control unit.

Abstract: In a device for controlling the amount of toner replenished to a developing device depending on the density of a reference image formed on a photoconductor, if the toner density of a developer in the developing device fluctuates extremely; there may occur toner scattering, formation of coarse or rough images, and carrier attachment. To overcome those problems, a photosensor is disposed to detect the toner density in the developing device, and when an output of the photosensor is outside of a predetermined range, a target value to be compared with the detected density of the reference image is modified.