Abstract: An image forming apparatus includes an original placement portion and a reference original portion outside of the original placement portion, a scanning device capable of selectively scanning either the original placement portion or the reference original portion, an image forming device for forming an image in accordance with the scanning device, a selection device for selecting the scanning of the original placement portion or the scanning of the reference original portion, and a reading device for reading an image of the reference original portion formed by the image forming device to evaluate a performance of the image forming device.

Abstract: An image forming apparatus includes a charger for charging a photosensitive drum, the charger having a charging wire extending in a lengthwise direction of the photosensitive drum, an optical system for illuminating a document and introducing a reflected light to the photosensitive drum to produce a latent image of the document, a detector for detecting a target portion of the charging wire causing a white line based on a copied image on copy paper, a cleaning member movable along the charging wire and adapted for cleaning the charging wire, a driver for moving the cleaning member along the charging wire, and a controller responsive to the detector for controlling the driver to move the cleaning member to the target portion of the charging wire and clean the target portion.

Abstract: An image forming apparatus includes a photosensitive body, a charge wire disposed along the photosensitive body at a specified spacing from the photosensitive body and adapted for charging the photosensitive body, the charge wire being tiltable on a plane passing an entirety of the charge wire and perpendicularly intersecting a surface of the photosensitive body. This apparatus is provided with a detector for detecting an image density distribution in a main scanning direction of copy paper, tilt angle calculator for calculating, based on a detected image density distribution, a correcting tilt angle of the charge wire to obtain a desired image density distribution in the main scanning direction, and a tilt angle controller for controlling the tilt angle in accordance with a calculated correcting tilt angle.

Abstract: The exposure apparatus is provided with a first mirror frame movement hampering means for hampering the movement of the first mirror frame in the exposing direction. The first mirror frame movement hampering means has a closure mounted on an operating opening on the main body and a movement hampering member mounted on the closure and positioned near a linking portion of the driving device of the first mirror frame and at a position at which the movement in the exposing direction is interfered. The movement hampering member is mounted on the closure to adjust its position freely within a predetermined range in the reciprocatingly moving direction of the first mirror frame.

Abstract: A scanning system driving device capable of quickly and gently starting a scanning system. This driving device includes an electromagnetic clutch for forward rotation, for transmitting a driving force from a driving source to a moving body for an optical system, and a control circuit for controlling the application of a voltage to the electromagnetic clutch. The control circuit applies a rated voltage in the form of pulses to the electromagnetic clutch at intervals of such OFF time that the moving speed of the moving body is reduced once when the illumination and the scanning of a document by the moving body are started.

Abstract: In a feed roller for mixing a developer and feeding it to a developing roller, a first mixing wing parallel to a rotating shaft is provided, a second spiral-shape mixing wing is diagonally provided in a manner to cross the first wing, and a spiral-shape groove for feeding a powder is formed on the one side located on the forward section with respect to rotating direction and being the powder scraping-up side of the both sides of said second mixing wing, along said second mixing wing, so as to enhance the feed performance, lateral-mixing performance and lateral-feed performance of the feed roller.

Abstract: An optical system driving device has a motor which rotates constantly in one direction for providing rotary driving power. A regular rotation electromagnetic clutch is connected to the rotating motor for transmitting driving power to the optical system for reciprocal movement of the optical system in one direction. A reverse electromagnetic clutch connected to the rotor motor transmits driving power to the optical system for reciprocal movement thereof in the opposite direction. A control circuit is provided which receives a pulse signal for controlling either the regular rotation or the reverse electromagnetic clutch at the start of the regular rotation electromagnetic clutch to gradually increase the effective driving power provided to the optical system to move the optical system at the start of movement.

Abstract: An image reading device including a contact glass on which an original sheet is set, an exposure lamp for irradiating a face of the original sheet on the contact glass to scan it, a photosensitive element provided below the contact glass, a first mirror for reflecting the light reflected by the original sheet in parallel with an original scanning direction, a second mirror for reflecting the light from the first mirror, a third mirror for reflecting the light from the second mirror, a lens for imaging the light from the third mirror on the photosensitive element, a first moving frame mounting the exposure lamp and first mirror and movable in the original scanning direction, a second moving frame mounting the second and third mirrors and movable following the first moving frame, first and second motors for shifting the first and second moving frames, respectively, and a controller for controlling a driving velocity of the second motor to keep the optical length from the face of the original sheet to be exposed

Abstract: A color image forming apparatus provided with a developing device for developing an electrostatic latent image formed on a latent image bearing member. The developing device comprises a plurality of developing units and supporting members for supporting the developing units thereon, and an arrangement is such that any developing units can be installed detachably on any supporting members each other. Then, the developing units have a developer supplying mechanism for feeding a developer each, and a supplemental developer container can be connected to each developer supplying mechanism. Then, the supplemental developer container is connected to one developing unit, and the developing unit provided with the supplemental developer is installed on a predetermined supporting member. The remaining developing units free from the supplemental developer container are then installed on the remaining supporting members.