Abstract: An image forming apparatus includes a main assembly and a drawer unit. The drawer unit includes a rotatable photosensitive drum, an optical print head, a relay substrate, a first wall portion, a second wall portion and a third wall portion continuously formed between an upstream end portion of the first wall portion and an upstream end portion of the second wall portion with respect to a drawing-out direction of the drawer unit from the main assembly. The relay substrate is provided on a surface of the third wall portion on an upstream side with respect to the drawing-out direction.

Abstract: An image forming apparatus includes a photosensitive drum, an image forming unit including an optical scanning device, a cleaning mechanism configured to clean a transparent window of the optical scanning device, and a control unit configured to cause the cleaning mechanism to perform a cleaning operation on the transparent window. The number of pages on which image formation is allowed to be performed for recording sheets in a period between cleaning operations performed by the cleaning mechanism is smaller in a case where image formation is performed on recording sheets in which the amount of generation of paper dust is large than in a case where image formation is performed on recording sheets in which the amount of generation of paper dust is small.

Abstract: An image forming apparatus includes a main assembly and a drawer unit. The drawer unit includes a rotatable photosensitive drum, an optical print head, a relay substrate, a first wall portion, a second wall portion and a third wall portion continuously formed between an upstream end portion of the first wall portion and an upstream end portion of the second wall portion with respect to a drawing-out direction of the drawer unit from the main assembly. The relay substrate is provided on a surface of the third wall portion on an upstream side with respect to the drawing-out direction.

Abstract: An image forming apparatus includes a photosensitive drum, an image forming unit including an optical scanning device, a cleaning mechanism configured to clean a transparent window of the optical scanning device, and a control unit configured to cause the cleaning mechanism to perform a cleaning operation on the transparent window. The number of pages on which image formation is allowed to be performed for recording sheets in a period between cleaning operations performed by the cleaning mechanism is smaller in a case where image formation is performed on recording sheets in which the amount of generation of paper dust is large than in a case where image formation is performed on recording sheets in which the amount of generation of paper dust is small.

Abstract: Optical scanning devices each have a Hall device for outputting a rotation signal by detecting a rotation of a motor. An optical scanning device controller has ASICs for performing startup control of the optical scanning devices, a CPU for controlling the ASICs, and a power supply path for supplying power to the optical scanning devices. The ASICs each have a FG counter for counting a clock signal and having a counter value to be reset by a rotation signal output from the Hall device. In a case where the motor is not normally driven when the optical scanning devices are started up, the CPU notifies an abnormality of the power supply device or the power supply path, based on a counter value of the FG counter acquired from each of the ASICs.

Abstract: Optical scanning devices each have a Hall device for outputting a rotation signal by detecting a rotation of a motor. An optical scanning device controller has ASICs for performing startup control of the optical scanning devices, a CPU for controlling the ASICs, and a power supply path for supplying power to the optical scanning devices. The ASICs each have a FG counter for counting a clock signal and having a counter value to be reset by a rotation signal output from the Hall device. In a case where the motor is not normally driven when the optical scanning devices are started up, the CPU notifies an abnormality of the power supply device or the power supply path, based on a counter value of the FG counter acquired from each of the ASICs.

Abstract: A rotating polygonal mirror has deflection faces for deflecting a light beam. A motor drives the polygonal mirror. A first detection unit outputs a first signal by detecting a light beam. A second detection unit outputs a second signal whose period is different from a period of the first signal, by detecting magnetic flux change. A specifying unit obtains a phase relationship between the first signal and the second signal, and specifies a deflection face. A storage unit stores setting information for setting whether to use rising or falling of the second signal to specify the phase relationship. The specifying unit determines whether to use rising or falling of the second signal in order to obtain the phase relationship.

Abstract: A rotating polygonal mirror has deflection faces for deflecting a light beam. A motor drives the polygonal mirror. A first detection unit outputs a first signal by detecting a light beam. A second detection unit outputs a second signal whose period is different from a period of the first signal, by detecting magnetic flux change. A specifying unit obtains a phase relationship between the first signal and the second signal, and specifies a deflection face. A storage unit stores setting information for setting whether to use rising or falling of the second signal to specify the phase relationship. The specifying unit determines whether to use rising or falling of the second signal in order to obtain the phase relationship.

Abstract: An image forming apparatus, including: a rotatable photosensitive member; a light source configured to emit a light beam; a rotary polygon mirror configured to deflect the light beam to scan a surface of the photosensitive member; a motor configured to rotate the rotary polygon mirror; a first rotation amount detecting unit configured to detect a rotation amount of the rotary polygon mirror; and a second rotation amount detecting unit configured to detect a rotation amount of the photosensitive member, wherein a first period of a first signal from the first rotation amount detecting unit and a second period of a second signal from the second rotation amount detecting unit have a relationship of an integral multiple, and wherein a rotation speed of the motor is controlled so that the first signal and the second signal are synchronized with each other while maintaining the relationship of the integral multiple.

Abstract: An image forming apparatus, including: a rotatable photosensitive member; a light source configured to emit a light beam; a rotary polygon mirror configured to deflect the light beam so that the light beam emitted from the light source scans a surface of the photosensitive member; a motor configured to rotate the rotary polygon mirror; a first signal generating unit configured to detect a rotation amount of the rotary polygon mirror to generate a first signal; and a second signal generating unit configured to detect a rotation amount of the photosensitive member to generate a second signal, wherein a rotation amount of the motor is controlled based on the first signal and the second signal so that the first signal is synchronized with the second signal.

Abstract: An image forming apparatus includes a measurement unit configured to emit light to a measurement target, and measure reflected light from the measurement target; a white reference plate disposed at a position opposed to the measurement unit; an image forming unit configured to form a measurement image on a sheet; and a calculation unit configured to, based on a measurement value of the white reference plate and a measurement value of the measurement image by the measurement unit, calculate a spectral reflectivity of reflected light from the measurement image. The calculation unit is configured to, after correcting a variation due to color change of the white reference plate with respect to the measurement value of the white reference plate, calculate the spectral reflectivity.

Abstract: An image-forming position displaces from an ideal position occurring due to a portion of a support substrate bending in a direction approaching a photosensitive drum. This displacement is set as a first gap data. Spot size expansion caused by bending of the support substrate can be reduced by using light amount control data that has been corrected in response to this first gap data. Furthermore, by using light amount control data corrected in response to second gap data that indicates displacement to an ideal position from exposure areas occurring due to decentering of the photosensitive drum, spot size expansion caused by decentering of the photosensitive drum can be reduced.

Abstract: An image forming apparatus includes a measurement unit configured to emit light to a measurement target, and measure reflected light from the measurement target; a white reference plate disposed at a position opposed to the measurement unit; an image forming unit configured to form a measurement image on a sheet; and a calculation unit configured to, based on a measurement value of the white reference plate and a measurement value of the measurement image by the measurement unit, calculate a spectral reflectivity of reflected light from the measurement image. The calculation unit is configured to, after correcting a variation due to color change of the white reference plate with respect to the measurement value of the white reference plate, calculate the spectral reflectivity.

Abstract: In the method of producing reduced iron according to the invention, fine iron oxides and powdery solid reductants are mixed, compacted into sheet-like compacts, and charged onto the hearth of a reduction furnace for reduction while maintaining the temperature inside the furnace at not less than 1100° C. As the sheet-like compacts can be obtained by compacting mixture of raw material by use of rollers or the like, processing time is much shorter than the case of pelletization or agglomeration. A drying step is unnecessary since feeds are placed no the hearth via a feeder chute or the like. The method is carried out with ease by use of the facility according to the invention. High quality hot metal can be produced by charging reduced iron in hot condition obtained by the method described as above into a shaft furnace or a in-bath smelting furnace for melting at high thermal efficiency.

Abstract: In the method of producing reduced iron according to the invention, fine iron oxides and powdery solid reductants are mixed, compacted into sheet-like compacts, and charged onto the hearth of a reduction furnace for reduction while maintaining the temperature inside the furnace at not less than 1100.degree. C. As the sheet-like compacts can be obtained by compacting mixture of raw material by use of rollers or the like, processing time is much shorter than the case of pelletization or agglomeration. A drying step is unnecessary since feeds are placed no the hearth via a feeder chute or the like. The method is carried out with ease by use of the facility according to the invention. High quality hot metal can be produced by charging reduced iron in hot condition obtained by the method described as above into a shaft furnace or a in-bath smelting furnace for melting at high thermal efficiency.

Abstract: An electric stapler including tension springs which prevent a second staple from entering a staple supply position of a magazine when a first staple is a jammed therein. The tension springs are connected between the arm of actuating links and connecting rods. The connecting rods connect the actuating links to the shaft of a motor. A clincher is provided which folds the legs of a U-shaped staple which have penetrated an article to a stapled against the article.

Abstract: An electric stapler including tension springs which prevent a second staple from entering a staple supply position of a magazine when a first staple is jammed therein. The tension springs are connected between the arm of actuating links and connecting rods. The connecting rods connect the actuating links to the shaft of a motor. A clincher is provided which folds the legs of a U-shaped staple which have penetrated an article to be stapled against the article.