Abstract: The invention provides a stackless continuous dual-sided copying method in photocopying machines.

Abstract: Disclosed are a positive charging color toner comprising a coloring agent and a positive charging electric charge controlling material in a fixing resin, wherein the fixing rein is an urethane-modified polyester resin having an acid value of not more than 5 KOHmg/g, a hydroxyl value of not more than 9 KOHmg/g, a weight-average molecular weight of 8,000 to 120,000 and a number-average molecular weight of 2,000 to 70,000, and the positive charging electric charge controlling material is (a) a quaternary ammonium salt having a melting point of not less than 200° C., or (b) a styrene-acrylate copolymer having a trisubstituted amminio group and a glass transition temperature Tg of not less than 55° C.

Abstract: In a sheet conveying unit, two conveying sections turn linked and spaced apart such that sheet jams arising in the course of conveyance through the conveying sections can be easily cleared single-handedly. Wherein the sheet-conveying unit functions to turn over, convey and store sheets in a dual-sided copying section inside a copying machine main body (1), it may include a main frame (30) that is withdrawable frontward from the copying machine main body (1); an intermediate tray (31) storing the reversed sheets; a lower conveyor (32); an upper conveyor (33); and a linkage (34). The upper and lower conveyors (33, 32) have upper and lower conveying guides (50, 45) and upper and lower conveying rollers (51, 46), respectively, and both conveyors are open/closable on the main frame (30) disposed above the intermediate tray (31).

Abstract: An image data processing apparatus is provided which is adapted to perform an image processing process suitable for each of a plurality of image modes on the basis of an output gradation reference curve and computation data. Output image data are generated by processing inputted image data on the basis of an output gradation curve which is prepared for each image mode on the basis of an output gradation reference curve and computation data. Therefore, output gradation curves for respective image modes need not preliminarily be stored in storage means. For example, if two output gradation reference curves and 16 computation data are preliminarily stored in the storage means, the inputted image data can be subjected to a process corresponding to any of 32 image modes by using an output gradation reference curve and a computation data in combination.

Abstract: An image forming apparatus having a developing mechanism for successively forming a plurality of color toner images on a photoreceptor; and an intermediate transfer member on which the plurality of color toner images are transferred from the photoreceptor in a superposed manner for primary transfer and from which the plurality of color toner images superposedly transferred thereon are transferred to a transfer sheet for secondary transfer. A circumferential ratio between the photoreceptor and the intermediate transfer member is 1:N (N is a non-integer).

Abstract: Disclosed are a positive charging color toner comprising a coloring agent and a positive charging electric charge controlling material in a fixing resin, wherein the fixing rein is an urethane-modified polyester resin having an acid value of not more than 5 KOHmg/g, a hydroxyl value of not more than 9 KOHmg/g, a weight-average molecular weight of 8,000 to 120,000 and a number-average molecular weight of 2,000 to 70,000, and the positive charging electric charge controlling material is (a) a quaternary ammonium salt having a melting point of not less than 200.degree. C., or (b) a styrene-acrylate copolymer having a trisubstituted amminio group and a glass transition temperature Tg of not less than 55.degree. C.

Abstract: The present invention provides an electrophotosensitive material comprising a conductive substrate and a single photosensitive layer containing a stilbene derivative (hole transferring material) represented by the general formula (1): ##STR1## (wherein R.sup.1, R.sup.2, R.sup.5 and R.sup.6 are the same or different and represent an alkyl group, an alkoxy group, an aryl group, an aralkyl group or a halogen atom; m, n, p and q are the same or different and represent an integer of 0 to 3, with the proviso that m and n represent a different integer when substituents represented by R.sup.1 and R.sup.2 are the same and that p and q represent a different integer when substituents represented by R.sup.5 and R.sup.6 are the same; and R.sup.3 and R.sup.4 are the same or different and represent a hydrogen atom or an alkyl group) and an electron transferring material, which is provided on the conductive substrate.

Abstract: A toner cartridge is constructed from a container having a discharge opening in its bottom end surface, and a shutter mechanism mounted on the bottom end of the container. In a lower part of the container, at least one partition wall is disposed. The discharge opening of the container is present not entirely in the bottom end surface, but only partly in the surface. To the entire edge of the discharge opening, a wall extending upwardly at an inclination angle .alpha. of at least 45 degrees to the horizontal is connected.

Abstract: A casing unitarily housing the photosensitive drum and developing device of a xerographic imaging system such that the thus composed imaging unit is retained in a predetermined operational position removably installed into a printing machine. The casing is configured such that when the imaging unit is removed from the printing machine, the imaging unit is retained in a posture equivalent to the predetermined operational orientation. Toner and developing agents are thus held in a steady state within the imaging unit, which particularly is an imaging unit in a lateral-transfer, vertical sheet-transport xerographic printing machine.

Abstract: An automatic document feeder includes first and second registration rollers for abutting the leading end of an original conveyed along a conveying path against their contact positions. The first registration roller is included in a plurality of reversing rollers arranged apart from each other along an axis of a supporting shaft of each of the reversing rollers. The reversing roller turn over the original along a reversing path that bypasses a part of the conveying path. There is provided a reversal guiding member arranged so as to cover a region between the adjacent reversing rollers. The reversal guiding member has guide surfaces curved along the peripheral surfaces of the reversing rollers as viewed along the axis of the supporting shaft. The reversal of the original is guided along the reversing path by the guide surfaces.

Abstract: An image-forming machine includes an image-forming unit, a transfer belt assembly disposed beneath the image-forming unit so as to freely ascend and descend between an acting position and a non-acting position, and a lift device for asending and descending the transfer belt assembly. The transfer belt assembly includes a driven roller, a tension roller, an endless belt wrapped around the driven roller and the tension roller, and a resilient urging device for resiliently urging the tension roller toward a direction of applying tension to apply tension to the endless belt. A tension release device is disposed which, when the transfer belt assembly is descended to the non-acting position, moves the tension roller in the direction in which tension is no longer applied, against a resilient urging action of the resiliently urging device, so that the application of tension to the endless belt is discontinued.

Abstract: An automatic document feeder of a type having a document inverting mechanism beside a document sending-in path is disclosed which, when a document located at a document exposure position is to be inverted, operates a conveying belt mechanism in a predetermined direction to convey the document by a predetermined amount in a direction away from a document positioning member, then brings a document positioning member to a retreat position, and then operates the conveying belt mechanism in a direction opposite to the predetermined direction to convey the document to the document inverting mechanism.

Abstract: A nitro group-containing naphthoquinone derivative represented by the following general formula: ##STR1## wherein R is a monovalent hydrocarbon group having a nitro group, and a ring A may be substituted with a substituent.This compound is a novel substance and is useful as an electron-transporting agent for an electrophotosensitive material. The electrophotosensitive material using the electron-transporting agent is highly sensitive, exhibits favorable repetitive properties, and makes it possible to favorably form images for extended periods of time.

Abstract: A toner device is constructed from a container having a discharge opening in its bottom end surface, and a shutter mechanism mounted on the bottom end of the container. In a lower part of the container, at least one partition wall is disposed with wall surfaces having edging defining the discharge opening(s). The discharge opening of the container thus forms a portion of the entire bottom end surface of the container. Also, the lower edging of the wall surfaces extend over the entire periphery of the one or more discharge openings, and each wall defining the discharge opening or openings extends upwardly at an inclination angle .alpha. of at least 45 degrees to the horizontal.

Abstract: During pre-scanning, a CPU calculates a gradation data width corresponding to the number of pixels which are 0.3% of the total pixels from a minimum value in a frequency distribution curve of gradation data of all pixels; calculates effective minimum and maximum values from the minimum and maximum values of the gradation data of all pixels and the gradation data width. A gradation correction i performed in a gradation correcting device during main scanning using following equation:f(x)=[{255-(S+L)}x.sup.2 +(S+L).sup.2 x-SL(S+L)-255S.sup.2 ]/(L.sup.2 -S.sup.2)wherex: gradation data before the correctionS: effective minimum valueL: effective maximum valuef(x): gradation data after the correction.

Abstract: Bypass sheet-feeding section for an electro-statographic image reproducing apparatus employing vertical sheet transport from sheet supply cassettes to the image reproducing section. The bypass sheet-feeding section serves to hold special copying sheets such as cardboard, OHP sheets, and surface-coated paper; but it can also serve to hold a stack of, for example, conventional-sized copy paper. The bypass/stack sheet-feeding section is fitted with drawer guides, and includes a sheet-loading plate, a sheet-feeding pickup roller, a sheet-feed plying roller pair and a mechanism for moving the loading plate vertically. The bypass/stack sheet-feeding section can be withdrawn integrally when it is pulled out from the side of the copier main unit.