Abstract: A sheet feeder for transporting a sheet unreeled from a roll includes a feed roller to unreel the sheet from the roll, a registration roller to transport the sheet unreeled by the feed roller to the image forming unit, a pressure roller pressing against the registration roller, forming a registration nip together with the registration roller, a movable sheet guide to guide the sheet to the registration roller, disposed between the feed roller and the registration roller in a sheet conveyance path, a support member to movably support the movable sheet guide relative to an apparatus body in which the sheet feeder is disposed, and a bias member to bias the sheet guide toward the sheet. The movable sheet guide wraps more of the sheet around the registration roller as a degree of tension of the sheet increases by moving against a bias force exerted by the bias member.

Abstract: A roll-sheet feeding device having a roll sheet wound in a roll to feed a portion of the roll sheet to an image forming unit, includes a progressive mechanism to transmit a drive force from a drive source to transfer the portion of the roll sheet from the roll in a progressive direction, a roll-sheet drive mechanism to receive the drive force transmitted via the portion of the roll sheet transferred in the progressive direction, a rewinding mechanism to transfer the portion of the roll sheet in a direction opposite to the progressive direction via the roll-sheet drive mechanism to rewind the roll sheet, and a regenerating mechanism to obtain the drive force from the roll-sheet drive mechanism and transmit the obtained drive force to the progressive mechanism to regenerate the transmitted drive force as another drive force in addition to the drive force from the drive source.

Abstract: A sheet feeder for transporting a sheet unreeled from a roll includes a feed roller to unreel the sheet from the roll, a registration roller to transport the sheet unreeled by the feed roller to the image forming unit, a pressure roller pressing against the registration roller, forming a registration nip together with the registration roller, a movable sheet guide to guide the sheet to the registration roller, disposed between the feed roller and the registration roller in a sheet conveyance path, a support member to movably support the movable sheet guide relative to an apparatus body in which the sheet feeder is disposed, and a bias member to bias the sheet guide toward the sheet. The movable sheet guide wraps more of the sheet around the registration roller as a degree of tension of the sheet increases by moving against a bias force exerted by the bias member.

Abstract: A light emitting element has spectral characteristics in a predetermined optical wavelength range. A photodetecting unit includes a photodetecting element capable of detecting a light in the optical wavelength range and performs an OE conversion of either one of a reflected light and transmitted light from a scanning target. A filter unit is arranged in an optical path from the light emitting element to the photodetecting element via the scanning target and having an optical transmission range within the optical wavelength range and covering a range of variation in the optical wavelength range.

Abstract: A roll-sheet feeding device having a roll sheet wound in a roll to feed a portion of the roll sheet to an image forming unit, includes a progressive mechanism to transmit a drive force from a drive source to transfer the portion of the roll sheet from the roll in a progressive direction, a roll-sheet drive mechanism to receive the drive force transmitted via the portion of the roll sheet transferred in the progressive direction, a rewinding mechanism to transfer the portion of the roll sheet in a direction opposite to the progressive direction via the roll-sheet drive mechanism to rewind the roll sheet, and a regenerating mechanism to obtain the drive force from the roll-sheet drive mechanism and transmit the obtained drive force to the progressive mechanism to regenerate the transmitted drive force as another drive force in addition to the drive force from the drive source.

Abstract: An optical device includes an optical element that transmits or reflects light, and scans the light onto a target surface to form a latent image on the target surface. The optical element includes a conducting portion that is located on at least any one of a light transmitting surface and a light reflecting surface, and a bias applying unit that applies a predetermined bias to the conducting portion.

Abstract: A light emitting element has spectral characteristics in a predetermined optical wavelength range. A photodetecting unit includes a photodetecting element capable of detecting a light in the optical wavelength range and performs an OE conversion of either one of a reflected light and transmitted light from a scanning target. A filter unit is arranged in an optical path from the light emitting element to the photodetecting element via the scanning target and having an optical transmission range within the optical wavelength range and covering a range of variation in the optical wavelength range.

Abstract: A disclosed optical device is physically movable with respect to a document surface or an image forming surface. The disclosed optical device includes substrates; optical element groups mounted on the substrates and composed of optical elements for image scanning or image forming, adjacent ones of the optical element groups being spaced at a predetermined distance in a direction that the optical device is movable; and a joining part joining the substrates and thereby maintaining the predetermined distance, the joining part having a thermal coefficient of expansion that is smaller than that of the substrates.

Abstract: An optical device includes an optical element that transmits or reflects light, and scans the light onto a target surface to form a latent image on the target surface. The optical element includes a conducting portion that is located on at least any one of a light transmitting surface and a light reflecting surface, and a bias applying unit that applies a predetermined bias to the conducting portion.

Abstract: A rolled paper conveying apparatus for conveying paper of a first rolled paper provided on a core. The apparatus includes a holding device configured to rotatably support the first rolled paper. The holding device is configured to enable movement of the first rolled paper from a first position on the holding device to a second position on the holding device. The apparatus further includes a first detector configured to detect whether the first rolled paper has moved from the first position to the second position. The holding device preferably includes a depressed portion configured to store the first rolled paper.

Abstract: A stepping motor controller is disclosed that is capable of reducing power consumption of a stepping motor. The stepping motor controller includes a storage unit to store object values of a driving current of the stepping motor, an accumulation unit to accumulate an amount of operation of the stepping motor, and a driving current setting unit to read out an object value corresponding to the amount of operation from the storage unit and set the driving current to the object value. Alternatively, the stepping motor controller includes an accumulation unit that calculates a cumulative amount of operation of the stepping motor, and a driving current setting unit that, when the amount of operation is greater than a predetermined value, determines a critical out-of-step current of the stepping motor by changing in increments the value of the driving current of the stepping motor, and sets the critical out-of-step current with a predetermined margin added as an object driving current of the stepping motor.

Abstract: An optical scanning device of the present invention includes a light source for emitting a light beam, a rotatable deflector having a plurality of deflecting faces, a first group of optical devices for shaping the light beam issuing from the light source and directing the shaped light beam toward the deflector, and a second group of optical devices for focusing the light beam deflected by the deflector on a surface to be scanned. The second group of optical devices split the light beam into at least two regions and cause each split light beam to scan a particular position on the above surface within a preselected range in the main scanning direction. The optical scanning device is small size and low cost.

Abstract: At least two image formation devices are provided. Each image formation device has a writing optical device that forms a latent image on a photosensitive member and a developing device that develops the latent image into a visual image. If the writing optical device in one of the two image formation devices is broken down, then the latent image is formed using the writing optical device in other of the two image formation devices. The latent image is developed to obtain the visual image using the developing device of the image formation device with the broken writing optical device.

Abstract: A rolled paper conveying apparatus for conveying paper of a first rolled paper provided on a core. The apparatus includes a holding device configured to rotatably support the first rolled paper. The holding device is configured to enable movement of the first rolled paper from a first position on the holding device to a second position on the holding device. The apparatus further includes a first detector configured to detect whether the first rolled paper has moved from the first position to the second position. The holding device preferably includes a depressed portion configured to store the first rolled paper.

Abstract: A stepping motor controller is disclosed that is capable of reducing power consumption of a stepping motor. The stepping motor controller includes a storage unit to store object values of a driving current of the stepping motor, an accumulation unit to accumulate an amount of operation of the stepping motor, and a driving current setting unit to read out an object value corresponding to the amount of operation from the storage unit and set the driving current to the object value. Alternatively, the stepping motor controller includes an accumulation unit that calculates a cumulative amount of operation of the stepping motor, and a driving current setting unit that, when the amount of operation is greater than a predetermined value, determines a critical out-of-step current of the stepping motor by changing in increments the value of the driving current of the stepping motor, and sets the critical out-of-step current with a predetermined margin added as an object driving current of the stepping motor.

Abstract: At least two image formation devices are provided. Each image formation device has a writing optical device that forms a latent image on a photosensitive member and a developing device that develops the latent image into a visual image. If the writing optical device in one of the two image formation devices is broken down, then the latent image is formed using the writing optical device in other of the two image formation devices. The latent image is developed to obtain the visual image using the developing device of the image formation device with the broken writing optical device.

Abstract: An optical scanning device of the present invention includes a light source for emitting a light beam, a rotatable deflector having a plurality of deflecting faces, a first group of optical devices for shaping the light beam issuing from the light source and directing the shaped light beam toward the deflector, and a second group of optical devices for focusing the light beam deflected by the deflector on a surface to be scanned. The second group of optical devices split the light beam into at least two regions and cause each split light beam to scan a particular position on the above surface within a preselected range in the main scanning direction. The optical scanning device is small size and low cost.

Abstract: An optical scanning apparatus includes two light sources, two beam shaping mechanisms, a light deflector, and two scanning beam focusing mechanisms. The light source emits a light beam. The beam shaping mechanism shapes the light beam. The light deflector deflects each light beam in a continuously changing direction thereby converting each light beam into a scanning light beam. The scanning beam focusing mechanism brings the scanning light beam to a focus on a photoconductive surface, and satisfies an equation of &Dgr;L cos &agr;>R/2 at a junction of the scanning light beam with the other scanning light beam on the photoconductive surface, wherein &Dgr;L represents an inherent light pass length variation, &agr; represents an incident angle, and R represents an inherent marginal distance.

Abstract: A power supplying apparatus for use in an electrophotographic apparatus. A switching device outputs an output current when a pulse of an input current is applied thereto, a switching control device controls a switching operation of the switching device by applying the pulse, and a transformer, a primary winding of which is connected with an output terminal of the switching device, generates a prescribed output voltage at its secondary winding by stepping-up an input voltage induced at the primary winding.

Abstract: In an image forming apparatus of the type including a movable belt and a cleaning blade for cleaning the belt, a toner image on the form of an exclusive line is formed on an image carrier between sheets and the transferred to the belt so as to feed toner to the edge of the cleaning blade. The toner prevents the edge of the cleaning blade from being turned over by the belt. The toner is fed to the cleaning blade in amounts different in the widthwise direction of the belt and can therefore be controlled in amount in the above direction.