Abstract: In an image forming apparatus, rollers to stretch and suspend a transfer belt to which color images are transferred are equipped with small diameter portions and a marker is formed, the marker facing to the small diameter portions sequentially when the transfer belt runs.

Abstract: A covering member 59 having a heat accumulating member 60 capable of holding heat effectively secured thereto is provided, and the covering members 59 are disposed so as to surround a heating roller 52 on both ends of the heating roller 52 and both ends of the maximum paper width are disposed. The covering member 59 is formed of a heat insulating material, and the circumferences except the inner circumferential surface of the heat accumulating member 60 are covered by the covering members 59. Further, a covering member 79 having a heat generating member 80 secured thereto may be provided in place of the heat accumulating member 60.

Abstract: An image forming unit includes a photosensitive drum as an image holding member for converting an optical image formed via an optical system into a latent image and subsequently depositing a developing material thereon to hold the image. The apparatus also includes a developing roller as a developing portion for supplying the developing material to develop the latent image held on the photosensitive drum to the image with the developing material. The apparatus further includes a gap regulating mechanism for setting bearings, disposed on both ends of a rotation drive shaft of the photosensitive drum, for rotatably fixing the photosensitive drum to a system main body frame and bearings, disposed on both ends of the developing roller, for rotatably supporting a rotation drive shaft of the developing roller by a developing portion main body. With such a unit, a peripheral surface of the photosensitive drum always maintains a constant gap from the peripheral surface of the developing roller.

Abstract: An image forming apparatus is provided with a table unit which can be taken out to a front side in a state of opening a front cover of a main body. A transfer belt unit integrally constituted by a transfer belt, a drive roller, a driven roller, a transfer roller and the like is detachably set on the table unit. In the case of setting the transfer belt unit to the apparatus main body, the transfer belt unit is set on the table unit, the table unit is inserted into the apparatus main body, and the transfer belt unit is lifted up by rotating a handle so as to be brought into contact with the process unit. Accordingly, it is possible to easily attach and detach the transfer belt unit with respect to the apparatus main body, thereby simplifying a replacing operation.

Abstract: The present invention comprises a photosensitive member supported for rotation within a unit case and a charger for uniformly charging the photosensitive member. The charger includes a conductive member in the form of a sheet held in contact with the photosensitive member and a supporting member having a non-flat cross section for supporting the conductive member, in which the charger applies a voltage formed of a direct-current voltage with an alternating-current voltage added thereto to the conductive member to thereby uniformly charge the photosensitive member. The charger is kept in place by having the supporting member fixed to vertical planes of the unit case at positions off vertical planes crossing the photosensitive member.

Abstract: A paper sheet transfer apparatus has lower and upper paper-sheet discharge rollers which contact each other and discharge a sheet of paper in accordance with the rotation thereof, and a corrugation roller located in the vicinity of the lower discharge roller. The corrugation roller has a holding portion mounted on the shaft of the lower discharge roller, and a roller main body elastically held by the holding portion and being able to be brought into contact with the sheet of paper. The holding portion and the roller main body are resin-molded integral as one body. By virtue of this structure, the paper sheet transfer apparatus can be assembled at low cost.

Abstract: A compact image forming apparatus which occupies a small floor area even though it has optional units connected to it. The apparatus includes an image forming device, a paper-reversing device attached to a side of the image forming device, a paper-feeding unit, a large-capacity paper-feeding unit, and a large-capacity storage unit. The image forming device and the paper-reversing device are mounted on the paper-feeding unit, which, in turn, is mounted on the large-capacity paper-feeding unit. The large-capacity paper-feeding unit is mounted on the large-capacity storage unit. The total bottom area of the image forming device and the paper-reversing section attached to the side of the image forming device is substantially equal to the top area of the paper-feeding unit, that of the large-capacity paper-feeding unit, and that of said large-capacity storage unit.

Abstract: An image forming apparatus includes an image carrying body for carrying a latent image, a developing device for applying a developing agent to the latent image to form a developing agent image on the image carrying body, a transferring device for transferring the developing agent image from the image carrying body onto a printable area of a recording medium. In the apparatus, a ratio of area of developing agent on the image carrying body to the printable area of the printing medium is detected. The developing device is controlled to apply the developing agent to the image carrying body to forcibly adhere the developing agent onto the image carrying body when the ratio is smaller than a specified ratio.

Abstract: A paper feeding mechanism for use in a printer apparatus, etc., includes upper and lower paper cassettes so provided as to be movable, a reverse guide provided below the lower paper cassette and having at least two divided parts, at least one of the divided parts being openable by moving the lowest paper cassette, and another reverse paper guide provided between the lower paper cassette and the upper paper cassette and having at least two parts of which at least one part is openable by moving the lower paper cassette. It is, therefore, possible to minimize an installation area occupied by the printer apparatus. Since the paper cassette is located in a spacing which is prepared against paper jamming, it is possible to make the printer compact as a whole.

Abstract: A developing device includes a casing removably mounted in an image forming apparatus and having a storing chamber in which developer is to be supplied. A package sealing developer therein is housed in the storing chamber. After the device is set in the image forming apparatus, the package is opened by an opening mechanism so as to supply the developer in the package into the storing chamber.

Abstract: A thermal print head having a base, a glass glaze layer formed on the base by electrically-heated welding, and heating elements formed on the glass glaze layer. A manufacturing method of a thermal print head uses a furnace to accommodate molten glass and a pair of opposed electrodes disposed within the furnace to melt the glass by flowing the current. The method comprises the steps of supplying electric power across the electrodes to cause electric current to flow through glass so as to melt glass, passing an elongated base through the molten glass accommodated in the furnace to form a glass glaze layer on the base, and forming heating elements on the glass glaze layer.

Abstract: A thermal print head having a base, a glass glaze layer formed on the base by electrically-heated welding, and heating elements formed on the glass glaze layer. A manufacturing method of a thermal print head uses a furnace to accommodate molten glass and a pair of opposed electrodes disposed within the furnace to melt the glass by flowing the current. The method comprises the steps of supplying electric power across the electrodes to cause electric current to flow through glass so as to melt glass, passing an elongated base through the molten glass accommodated in the furnace to form a glass glaze layer on the base, and forming heating elements on the glass glaze layer.

Abstract: A laser beam printer includes a beam deflector for selectively exposing a surface of a drum-like photoreceptor to form an electrostatic latent image thereon, a developer for depositing toner powder to the latent image, a transfer charger for transferring the developed image onto paper, and a tray for sequentially stacking paper sheets carrying the transferred images thereon. Since the transfer charger is disposed above the photoreceptor to face it, the image is transferred on a lower surface of the paper. After the image is transferred to paper, the paper is delivered to the tray by delivery rollers. The transfer charger and the delivery tray are mounted on a pivotal door, thus enlarging a space between the photoreceptor and the transfer charger.

Abstract: In an optical deflector of a polygonal mirror type, a rotating shaft is supported by a pair of journal bearings of a herringbone dynamic pressure type and a magnetic thrust bearing. The magnetic thrust bearing comprises first and second annular magnets. The first annular magnet is coaxially fixed to the shaft and has a first magnetic pole arrangement on its outer surface. The second annular magnet is fixed to a housing, and has its inner surface opposed to the outer surface of the first magnet and magnetized with a pole arrangement different from the pole arrangement of the first magnet, so that the first and second magnet attract one another to suspend the shaft. Ferromagnetic plates are fixed on both upper and lower surfaces of the first and second magnets.

Abstract: A copying apparatus comprises a document table disposed on the top of a housing and having a glass platen on which an original document is to be laid, the glass platen being movable between a first position to cover the top of the housing and a second position to open the top over the length and breadth thereof, a copying mechanism disposed inside the housing to reproduce on a sheet of copying paper an image of the original document laid on the glass platen, and a protective member attached to the housing for covering the opening of the housing, having openings and being able to move between a third position and a fourth position. The protective member covers the upper portion of the copying mechanism while staying in the third position and the protective member exposes the upper portion of the copying mechanism while staying in the fourth position when the glass platen is in the second position.

Abstract: A developing device develops an electrostatic latent image formed on a photosensitive drum by using a magnetic developer. The developing device comprises a body frame having a storage section storing the magnetic developer, a developing roller disposed inside the body frame and including a first section facing the storage section and a second section facing the photosensitive drum, for supplying the magnetic developer in the storage section to the second section through the shift of a magnetic field, whereby the magnetic developer supplied to the second section by the developing roller is attracted to the electrostatic latent image on the photosensitive drum, and an intermediate plate provided in the frame body under the developing roller to bear thereon the magnetic developer dropped from the developing roller.

Abstract: In an electronic copier provided with a light-sensitive medium, a charging station, an exposure station, a developing station, a transfer station and a fixing unit, the charging station includes a plurality of contact charging elements in contact with the light-sensitive medium and a voltage supply means for applying voltages to the contact charging elements. A voltage continuously rising in a predetermined period of time is supplied from the voltage supply means to the contact charging elements with the rotation of light-sensitive medium, and the light-sensitive medium is thus uniformly charged.

Abstract: A charging device includes a piled cloth contact which is formed of pliable material, has an electric resistance chosen to be 10.sup.8 .OMEGA..multidot.cm and contacts a photosensitive layer of a photosensitive drum. An electrode is connected to the contact and has a lower electric resistance than that of the contact. A D.C. power source and A.C. power source supply D.C. and A.C. voltages on the electrode to charge the photosensitive layer.