Abstract: An image forming apparatus includes a main casing; a photosensitive member; a process cartridge that can be installed or removed with respect to the main casing along a removal path; a scanner unit located above the process cartridge when the process cartridge is installed in the main casing; a sheet accommodating portion located at a bottom portion of the main casing; a pick-up roller located above the sheet accommodating portion; and a feed path along which a sheet can be conveyed from the sheet accommodating portion to a discharge port.

Abstract: An image forming apparatus includes a recording medium accommodating portion that is capable of accommodating a recording medium; a feed path along which the recording medium is capable of being fed from the recording medium accommodating portion; and a detector, disposed on the feed path, capable of detecting (1) a cartridge that is capable of being installed in the image forming apparatus when the cartridge is installed in the image forming apparatus and (2) the recording medium when the recording medium passes through the feed path when the cartridge is installed in the image forming apparatus.

Abstract: Left and right frames are formed of a resin containing no glass fibers and bridged together by a tray formed of steel, a chute formed of resin, and underbars formed of steel. Each frame has a box-shape configured of a plate surface and side surfaces formed by bending the edges of plate surface in a common direction perpendicular to the plate surface, thereby preventing the plate surface from bending significantly. When the tray and underbars expand, then the frames bend slightly to absorb the load.

Abstract: An image forming apparatus includes a body frame having left and right side frame parts and a partition wall frame part that is placed below a sheet path passing through an image forming unit in a process unit. The process unit and a drive transmission system frame having a drive mechanism for transporting sheets are placed in a longitudinal direction on an outer face of the left side frame part. A high voltage power board, a low voltage power board, and an engine control board for the drive mechanism are fixedly placed horizontally on a lower face side of the partition wall frame part. A main control board is placed substantially vertically so as to become adjacent to the drive transmission system frame and extend along the outer face of the left side frame part. The boards and parts are connected by connection lines.

Abstract: A dial is provided to a laser printer such that only a portion of the dial is exposed in an accommodating area for accommodating a process cartridge. A user can manually rotate a conveying roller to convey a paper through a conveying path by operating the dial. The dial is disposed coaxial with an auger. The auger operates in association with the conveying roller because of an auger gear being engaged with a conveying gear. A driving force from a driving motor is transmitted to the conveying gear via a planetary gear. When a paper jam occurs, the user operates the dial in order to move the planetary gear, thereby switching the state for communicating the driving force from the drive motor to the conveying roller from a communicating state to a non-communicating state.

Abstract: A laser printer includes a guide member for guiding a paper. The guide member includes an outer guide and an inner guide, and a top surface of the outer guide serves as a portion of a bottom surface of an accommodating space where a process cartridge is accommodated. If a paper jam occurs in a transport path defined between the outer guide and the inner guide, then a user opens a front cover and removes the process cartridge from the accommodating space. Then, the user grabs and pulls the jammed paper out of the casing. While the paper bends at an acute angle at the end of the guide member, rollers provided at the end of the guide member enable the paper to be pulled out without being torn.

Abstract: An image forming apparatus includes a body frame having left and right side frame parts and a partition wall frame part that is placed below a sheet path passing through an image forming unit in a process unit. The process unit and a drive transmission system frame having a drive mechanism for transporting sheets are placed in a longitudinal direction on an outer face of the left side frame part. A high voltage power board, a low voltage power board, and an engine control board for the drive mechanism are fixedly placed horizontally on a lower face side of the partition wall frame part. A main control board is placed substantially vertically so as to become adjacent to the drive transmission system frame and extend along the outer face of the left side frame part. The boards and parts are connected by connection lines.

Abstract: Left and right frames are formed of a resin containing no glass fibers and bridged together by a tray formed of steel, a chute formed of resin, and underbars formed of steel. Each frame has a box-shape configured of a plate surface and side surfaces formed by bending the edges of plate surface in a common direction perpendicular to the plate surface, thereby preventing the plate surface from bending significantly. When the tray and underbars expand, then the frames bend slightly to absorb the load.

Abstract: A drive mechanism for rotating a drive roller includes an input transmission mechanism for transmitting a drive force from a motor, an output transmission mechanism for transmitting the drive force to the drive roller, an intermediate transmission mechanism for selectively transmitting the drive force from the input transmission mechanism to the output transmission mechanism in either a first direction or a second direction, and a switching mechanism for moving the intermediate transmission mechanism to a first position to drive the output transmission mechanism in the first direction or a second position to drive the output transmission mechanism in the second direction.

Abstract: An image forming apparatus includes an image forming unit having an image forming portion positioned over a partition wall that vertically partitions a body frame above a cover plate. A second circuit board in which a tall electronic component-mounting side is upward directed is placed in a space between the partition wall and the cover plate. A first circuit board in which an electronic component-mounting side is downward directed is placed on a lateral side of the second circuit board. The first and second circuitp boards are placed in a stepwise manner so that the level of the first circuit board is higher than that of the second circuit board. A return path for reversely transporting a sheet is formed between the cover plate and the upper face of a return tray.

Abstract: An image forming apparatus and a method of forming an image by the image forming apparatus that includes an image forming unit for forming an image onto a recording medium, a supply path for supplying a recording medium to the image forming unit, a first discharge path for discharging the recording medium, a return path, connected with the first discharge path, for returning the recording medium to the image forming unit, a second discharge path, substantially parallel with the supply path, for discharging the recording medium, and a guide member movable from a first position to create the first discharge path and the return path to a second position to create the second discharge path.

Abstract: An image forming apparatus includes an image forming unit for forming an image onto a recording medium, a supply path for supplying a recording medium to the image forming unit, a first discharge path for discharging the recording medium, a return path, connected with the first discharge path, for returning the recording medium to the image forming unit, a second discharge path, substantially parallel with the supply path, for discharging the recording medium, and a guide member movable from a first position to create the first discharge path and the return path to a second position to create the second discharge path.

Abstract: A drive mechanism for rotating a drive roller includes an input transmission mechanism for transmitting a drive force from a motor, an output transmission mechanism for transmitting the drive force to the drive roller, an intermediate transmission mechanism for selectively transmitting the drive force from the input transmission mechanism to the output transmission mechanism in either a first direction or a second direction, and a switching mechanism for moving the intermediate transmission mechanism to a first position to drive the output transmission mechanism in the first direction or a second position to drive the output transmission mechanism in the second direction.

Abstract: A developing device in an image forming apparatus is provided with: a developing roller opposed to a photosensitive body, on which an electro-static latent image is formed, for developing the electro-static latent image by using toner; a supplying roller for supplying the toner to the developing roller; a wall member prescribing a developing chamber, in which the developing roller and the supplying roller are disposed, and a toner supply port, through which the toner is supplied into the developing chamber; a pair of upper and lower augers disposed in the developing chamber at a vicinity of the toner supply port for carrying and circulating the toner supplied through the toner supply port, and adhering the toner onto the supplying roller; and an auger partition plate disposed between the upper and lower augers for restricting movement of the toner between the upper and lower augers.

Abstract: A developing device containing an initial developer in a sealed initial developer storage space sealed with a film and a magnetic toner in a sealed toner container is mounted on the frame of an electrostatic apparatus. Then, the film sealing the initial developer storage space and the toner container is removed to let the initial developer fall into an initial developer containing space near a developing sleeve and to let the magnetic toner fall into a space separated from the initial developer containing space by a partition wall. As the magnetic toner of the initial developer is consumed with the progress of printing operation, the toner flows through a gap defined by the partition wall into the initial developer containing space. The initial developer and the magnetic toner can be surely supplied to the developing sleeve simply by removing the film before using the developing device.

Abstract: In an electrostatic device that uses a resistance film for electrifying a latent image holder in printing devices, such as a photo-copier or a facsimile, at least one electrode borders the resistance film. The electrostatic device confronts a latent image holder, having a cylindrical shape, across a narrow gap and along the length of the latent image holder. With this structure, applying D.C. voltage to the electrode electrifies the latent image holder via the resistance film. Since the resistance film and the electrode overlap each other, the potential on the latent image holder is dependent on the surface resistance rather than the volume resistance of the resistance film giving the electrostatic device an immunity from nonuniformity or flaws in the surface of the resistance film. In addition, an electrostatic device of this invention has a structural advantage over conventional scorotron devices.

Abstract: One unit type processing unit to be assembled in a laser printer for facilitating replacement work. The processing unit houses therein a photosensitive drum with a part being exposed, a charging unit, a developing unit and cleaning unit. The processing unit is also provided with a flexible protective cover for covering the exposed area of the photosensitive drum when an upper frame of the laser printer is opened. The protective cover can be rolled into a compact configuration and is positioned in a dead space at a position beside the exposed area when the cover is moved away from the exposed area and when the upper frame is closed for printing operation. The rolled cover is stretchable to cover the exposed area when the upper frame is opened.

Abstract: An integral type processing unit has a photosensitive drum, a developing unit for forming a developer toner image on the photosensitive drum, and a cleaning unit for scraping off residual toners from the drum. The developing unit does not have sufficient internal volume for accumulating therein the developer toners whose amount meet with the service life of the other components. Therefore, toner containers are replaceably attached to the developing unit for supplementing the developer toners therein. In order to limit the replacement times of the toner containers, each of the toner containers are provided with a segment separable therefrom. Further, a receiving segment is provided at the developing unit engageable with the separable segment. The receiving segment has a predetermined number of receiving portions. If all receiving portions are filled with the separable segments, it becomes no longer possible to further replace the toner container with a new container.