Abstract: An image forming apparatus includes a fixing unit having a heat source, a temperature detecting unit for detecting a temperature of the fixing unit, an initial operation necessity detecting unit for determining whether an initial operation should be performed in the image forming apparatus, an initial operation selecting control unit for selecting an initial operation from among a plurality of predetermined initial operations based on the temperature detected by the temperature detecting unit when the initial operation necessity detecting unit detects that the initial operation should be performed, and a control unit for controlling the fixing unit so that the fixing unit performs the initial operation selected by the initial operation selecting control unit.

Abstract: An image forming apparatus includes a fixing unit having a heat source, a temperature detecting unit for detecting a temperature of the fixing unit, an initial operation necessity detecting unit for determining whether an initial operation should be performed in the image forming apparatus, an initial operation selecting control unit for selecting an initial operation from among a plurality of predetermined initial operations based on the temperature detected by the temperature detecting unit when the initial operation necessity detecting unit detects that the initial operation should be performed, and a control unit for controlling the fixing unit so that the fixing unit performs the initial operation selected by the initial operation selecting control unit.

Abstract: A heat roller fixing device which can substantially make uniform the amount of deflection of a backup roller over the axial length thereof to improve a paper feed force at an axially central portion of the backup roller. The heat roller fixing device includes a heat roller rotatably mounted to a frame, and a backup roller pressed against a heat roller by coil springs to follow rotation of the heat roller. The backup roller includes a hollow cylinder, a solid metal shaft inserted in the hollow cylinder and having a pair of large-diameter portions spaced a given distance from each other. One of the large-diameter portions of the solid metal shaft is fixed to the hollow cylinder such as by a pin therethrough, and the solid metal shaft is biased toward the heat roller by the coil springs.

Abstract: A computer controlled printer is capable of printing at different print densities. This makes it possible to automatically determine an optimum print density according to a normal operational mode with serious consideration given to print quality and an economy operational mode with serious consideration given to operating costs, thereby decreasing the print consumables. The printer has a print mechanism section for printing papers according to print data and a print controlling section for controlling the print mechanism section. The print controlling section selects either a print density in a normal mode or a print density in an economy mode according to the normal/economy instructions and controls the print density of the print mechanism section correspondingly.

Abstract: A toner image fixing device includes a heat roller, and a backup roller engaged with the heat roller to form a nip therebetween. A paper carrying a toner image is passed through the nip whereby the toner image is thermally fused and fixed on the paper. The heat roller, which is stained by a part of the fused toner during the fixing process, should be cleaned before a toner image is fixed on a successive paper without staining. To this end, a cleaning roller made of a felt material is pressed against the heat roller so as to be rotated together with the heat roller by a frictional force acting therebetween. The cleaning roller must be periodically replaced. The fixing device is constituted such that the replacement of the cleaning roller can be easily and quickly carried out.

Abstract: The present invention relates to an optical scanning unit used for exposing a photosensitive drum of an image forming apparatus to light, and an image forming apparatus using this optical scanning unit. This optical scanning unit comprises a light source; an optical scanning mechanism for scanning with light from the light source; a start detecting mechanism for detecting scan light of the optical scanning mechanism at an end portion of a scanning range of the scan light to detect beginning of light scanning; and a frame which has a higher rigidity than that of a frame of an image forming apparatus and to which the light source, the optical scanning mechanism and the start detecting mechanism are attached.

Abstract: There is disclosed a process cartridge exchangeably provided to an image forming apparatus provided with an endless light-sensitive carrier, a mechanism for charging the light-sensitive carrier, a cleaner for cleaning residual toner on the light-sensitive carrier, a cartridge frame installed with at least the light-sensitive carrier, the charging mechanism and the cleaner, the cartridge frame having a fulcrum hole, and wherein a developing unit is detachably provided to the cartridge frame for developing an electrostatic image on the light-sensitive carrier, the developing unit including a developing unit frame having a free fit hole and connection rod freely fitted into the fulcrum hole and as well freely fitted to the free fit hole of the developing unit frame for installing the developing unit to the cartridge frame such that the developing unit is rotatably movable with respect to the cartridge frame.

Abstract: A printer capable of operation in an economy mode as well as in a normal mode. The printer includes a print mechanism for printing in accordance with print data. The printer also includes a print controller which controls the print mechanism. The printer is provided with a mode of operation selector for selecting between a normal mode of operation in which the print quality is relatively emphasized and an economy mode of operation in which operating costs are relatively emphasized. The print controller controls the print density at a first level when the normal mode of operation has been selected and at a second reduced level when the economy mode of operation has been selected.

Abstract: Disclosed is an image forming apparatus in which separation unit for electrostatically separating a sheet from a latent image carrier is provided on an openable and closable frame.

Abstract: In an electrographic printer which comprises a photoconductive drum (5), a precharger (7), an LED array (11), a developer (8), a cleaner (9), a transfer-charger (3) and a fuser unit (4), in which the photoconductiver drum (5), the precharger (3), the developer (8) and the cleaner are built-in in a casing to form a process cartridge (2), a housing (1) of the printer is a clam-shell type having of a lower frame (1a) and an upper frame (1b) hinged to the lower frame at the rear end thereof so that an opening is formed between both frames (1a, 1b) when the upper frame (1b) is separated from the lower frame (1a), through which opening the process cartridge (2) is inserted into and removed from the housinhg (1).