Abstract: The present invention is intended to provide a compact development apparatus using a nonmagnetic one-component toner. The apparatus comprises a toner storage container, a toner supply roller, a toner passage through which supplied toner passes, and an attracting fan for attracting the toner and generating a toner powder stream. The toner is held in the toner storage container. The toner supply roller supplies the toner from a supply port of the storage container. The toner passage is provided with an opening opposite to a photosensitive drum. The toner supplied into the toner passage and frictionally charged is attracted by the attracting fan. The toner travels from the opening to the drum. The toner adheres to an electrostatic latent image on the drum and thus the image is developed. Unused toner is transported into the toner passage and recovered.

Abstract: Toners comprised of a cyan toner, a magenta toner, a yellow toner, an orange toner, a green toner, and a black toner, each of said toners being comprised of resin and pigment; and wherein the pigment for the orange toner is Orange 5, C.I. number 12075, Orange 13, C.I. number 21110, Orange 16, C.I. number 21160, or Orange 34, C.I. number 21115, and the pigment for the green toner is Green 7, C.I. number 74260, or Green 36, C.I. number 74265, and wherein said pigment for each toner, excluding black, is prepared by flushing each of said pigments, wherein a cyan, magenta, yellow, orange, and green pigment water wet cake is mixed with toner resin, and the water is removed, or substantially removed to generate pigmented resins.

Abstract: REaD(Recharge Expose and Develop) electrophotographic printing using additive color toners and inhibited image on image development. Inhibited image on image development is achieved by setting the exposure set points such that exposure losses incurred when imaging through previously developed toner reduces the electrostatic potential for developing over the developed toner, by using a DC corona system during recharging so as to enhance the voltage drop across the previously developed toner(s), and/or by increasing the developed toner mass to increase the thickness of the dielectric properties of the developed toner.

Abstract: A color electro-photographic apparatus including a photosensitive belt disposed for movement along a path in which a major portion of the path extends in a substantially vertical direction, a plurality of developing units arranged in a stack along one side of the photosensitive belt, and an intermediate transfer body disposed adjacent an other side of the photosensitive belt at a lower portion thereof. The color electro-photographic apparatus also includes a paper cassette extending in a horizontal direction at a part of the apparatus below the photosensitive belt so that paper travels from an end of the paper cassette along a vertical path without bending back upon itself prior to image transfer by the intermediate transfer body.

Abstract: A method for and apparatus for creating partial gamut color images in a single pass. A plurality of latent discharged area images are formed using a single exposure. A first discharged area image is developed followed by recharging of the photoreceptor containing the images. The images are then subjected to a partial erase step followed by the development of a second discharged area image. All images formed subsequent to the first discharged image except for the last image are preceded by recharging and partial erase to thereby optimize development and cleaning fields.

Abstract: A color image forming apparatus having a simple mechanism for switching plural photosensitive drum units and still maintaining a high resolution image is provided. In the apparatus, each image forming unit including each color photosensitive drum is disposed around a rotating shaft of a carriage. Each photosensitive drum has a coupling plate at one end, which is engaged by a drive side coupling plate for transmitting a drive force to the photosensitive drum, when the image forming units is moved to the image forming position. An output shaft that rotates the drive side coupling plate supports an edge of a photosensitive drum shaft in alignment. A toner image formed on the photosensitive drum is transferred onto a transfer belt, which rotates at a constant speed, one by one to form a multicolor image on the transfer belt. The multicolor image on the transfer belt is transferred onto a paper sheet. A transmission between a motor and the carriage include a worm gear.

Abstract: Embodiments of a compact electrophotographic color developer module are shown and described, each embodiment including generally vertically-oriented, self-contained developers, stacked or radially fanned-out above the photoconductor drum. The developers are preferably either wedge-shaped or rectangular, and preferably have cylindrical sleeves less than about 2 inches apart. The compact developer module and cooperating image transfer system have a small form factor and footprint and may be used in a wide variety of electrophotographic platforms with minimal changes. A cam system may be included to allow either contact, non-contact, or close-jump-gap development, with a simple code or ROM change. The photoconductor drum is sized to carry less than a complete image, because the image is transferred to an intermediate transfer member before transfer to paper.

Abstract: A color printer including a photoconductive belt, a black developing unit which is located adjacent the photoconductive belt and a revolving type developing unit which is located adjacent the photoconductive belt and has a developing position on the photoconductive belt which is different from that of the black developing unit. The revolving type developing unit has a yellow developing device, a magenta developing device and a cyan developing device, each including a detachable toner cartridge by which yellow toner, magenta toner and cyan toner is replenished. The black developing unit is replaceable independent of the revolving type developing unit by being removably mounted on a removable frame on which the revolving type developing unit is mounted. Both developing units are removable from the color printer as a body by removal of the removable frame from the color printer.

Abstract: A method and apparatus which forms a desired toner image on a receiver are disclosed. The method comprises transferring marking toner particles from an intermediate transfer member to a receiver in the presence of an electric field which urges the marking toner particles toward said receiver. When transferring the marking toner particles to the intermediate transfer member, the surface of the intermediate transfer member contacts non-marking toner particles in some areas which receive marking toner. The marking toner comprises toner particles having transfer assisting particles adhering to the surfaces of the toner particles, said transfer assisting particles having a number average diameter of less than 0.4 .mu.m.

Abstract: A toner for full-color development for use in a developing system of a full-color image forming apparatus which comprises a binder resin having a glass transition point Tg of from 60.degree. to 75.degree. C., a number-average molecular weight Mn of from 3500 to 6000, a ratio of a weight-average molecular weight Mw to the number-average molecular weight Mn (Mw/Mn) ranging from 3 to 8, and a difference between a temperature T.sub.1 at the apparent melt viscosity of 1.times.10.sup.5 poise and a temperature T.sub.2 at the apparent melt viscosity of 1.times.10.sup.6 poise DT (=T.sub.1 -t.sub.2) in the range of from 8.degree. to 15.degree. C.

Abstract: Maintenance performance is promoted and a vivid printed image is provided in an electrophotographic device capable of conducting color printing. Cartridges corresponding to different printing colors, each of which includes a photosensitive body, are stacked in a vertical direction. A recording sheet is fed along a sheet feeding path and brought into contact with the photosensitive bodies corresponding to the respective colors, and toner images of the respective printing colors are transferred on the recording sheet. A transfer belt for feeding the recording sheet is arranged in a front cover, and the transfer belt is exposed when the front cover is opened. Therefore, correcting a mis-feeding of the recording sheet is facilitated. Also, the respective cartridges are spaced apart such that optical paths are provided between the cartridges so that optical beams corresponding to the respective printing colors may be directly irradiated onto the corresponding photosensitive bodies.

Abstract: An image forming method has a developing step of developing an electrostatic latent image by the use of a developer to form a toner image on an electrostatic latent image bearing member, a primary transfer step of transferring the toner image onto an intermediate transfer member to which a voltage is applied, and a secondary transfer step of transferring onto a transfer medium the toner image held on the intermediate transfer member, while a transfer means to which a voltage is applied is pressed against the transfer medium. The developer has a toner. The toner is a black toner having at least i) black toner particles formed of a binder resin with a colorant dispersed therein and ii) an inorganic fine powder. The black toner has the value of shape factor SF-1 of 110<SF-1.ltoreq.180, the value of shape factor SF-2 of 110<SF-2.ltoreq.140, and the value of ratio B/A of 1.

Abstract: A multi-color image forming apparatus includes a rotatable endless image forming member, plural exposure devices provided inside of the image forming member, and plural units each including a charger to electrically charge an outer surface of the image forming member and a developing device containing a color toner of plural different color toners to develop a latent image. Each of the plural units are disposed on the outer surface of the image forming member so as to be opposite to one of plural exposure devices so that multi-color toner images can be formed on the outer surface of the image forming member during a single rotation of the image forming member. in addition, each of the plural units is detachable from the apparatus independently of other units.

Abstract: An image formation method for forming an image of a plurality of colors through a charging step, an image exposing step, a developing step and a transferring step, wherein the image exposing step is made up of a first image exposing step and a second image exposing step, the developing step of at least one color is carried out after the first image exposing step, and in the subsequent second image exposing step, the toner image area formed by the developing step is exposed and charge latent images for forming toner images of the rest of the colors are formed while a potential of the toner image area is selectively shifted.

Abstract: An image forming apparatus includes a plurality of photosensitive members, charging devices provided respectively with the photosensitive members to charge the photosensitive members, an exposing device for exposing the charged photosensitive members to image light, developing devices for developing electrostatic images on the photosensitive members with toners of different colors, a transfer device for sequentially conveying a toner image carrying medium to the transfer-positions of the photosensitive members and transferring the toner images of different colors to overlap each other on the toner image carrying medium, and a color mixing device for mixing the colors of the stacked toner images. The charge amounts of the toners for developing the electrostatic images on the photosensitive members are substantially equal.

Abstract: An electrophotographic printer produces a multi-color image on a moving photoconductor (OPC) and includes a laser/scanner arrangement for producing first and second beams to expose the OPC at spaced-apart exposure stations. The OPC is charged to a reference state prior to exposure. First and second developer stations are positioned between the first and second beam exposure stations and third and fourth developer stations are positioned after the second beam exposure station in the direction of movement of the OPC. A controller modulates the laser, during each scan, in accordance with subpixel color data from a pair of color planes to achieve a tri-level charge state (including the reference state) on the OPC. The first and second developer stations apply charged toners, selectively, in accord with the tri-level charge state produced by the scan of the first beam.

Abstract: A digital copying machine provided with a device for forming color images by the formation, superposition of the images for each color in the order of the color face including a device for coding, compressing of a plurality of image signals separated in color by one page portion of the document so as to store in memory, a device for decoding, extending a plurality of compressed image signals stored in the memory, a color correcting device for converting a plurality of extended image signals into the color image signals for image formation so as to make the memory capacity smaller.

Abstract: A system and method for color mixing control in an electrostatographic printing system. An operative mixture of colored developing material is continuously replenished with selectively variable amounts of developing materials of basic color components making up the operative mixture. The rate of replenishment of various color components added to the operative mixture is controlled to provide a mixture of developing material capable of producing a customer selectable color on an output copy substrate. A colorimeter is provided for monitoring the color of a test image printed with the operative mixture of developing material in the supply reservoir so that the color thereof can be brought into agreement with a color required to produce the customer selectable output color.

Abstract: An image forming apparatus such as a copier or a printer for forming a color image. The image forming apparatus includes: a transparent photoreceptor drum for retaining a multi-color toner image in which the wall-thickness and an inner diameter of the drum are respectively between 2.5 mm and 8 mm and between 60 mm and 200 mm; plural chargers, provided on the periphery of the photoreceptor drum, for charging the drum surface; plural imagewise exposure systems, provided inside of the photoreceptor drum, for forming latent images on the drum surface; and plural developers, provided on the periphery of the photoreceptor drum, for developing the latent images with different color toners so as to form a superimposed multi-color toner image on the drum surface while the photoreceptor drum is being rotated one time.

Abstract: An electrophotographic printing machine, wherein an electrostatic latent image recorded on a photoconductive member is developed with toner to form a visible image thereof, wherein the improvement includes an apparatus for alleviating toner contamination of the electrophotographic printing machine while maintaining high quality visible images. The apparatus includes a first housing defining a chamber storing a supply of toner of a first color; the first housing including a first toner donor member spaced a first predetermined spacing from the surface and being adapted to transport toner of the first color to a region opposed from the surface, and a second toner donor member spaced a second predetermined spacing from the surface and being adapted to transport toner of the first color to the region opposed from the surface; and wherein the first predetermined spacing is substantially greater than the second predetermined spacing.

Abstract: An intermediate transfer drum is employed and a photosensitive belt having a length equal to the outer peripheral length of the intermediate transfer drum is arranged with a vertical orientation. Developing units of the same shape are arranged on one side of the photosensitive belt, and a charging unit and a cleaner are arranged on the other side. The intermediate transfer drum is placed under or diagonally under the photosensitive belt. A transfer mechanism for transferring an image on the intermediate transfer drum to a sheet of paper is placed under or diagonally under the intermediate transfer drum. By this arrangement and construction, a small-size color electro-photographic apparatus having a size capable of easy use as a desk-top apparatus is provided, which satisfies quality of image, speed of printing, and easiness of maintenance requirements at the same time.

Abstract: A multi-color imaging apparatus utilizing recharging between two image creation steps for recharging a charge retentive surface to a predetermined potential prior to forming a second of the two images. The two images are formed using toner particles which are subject to under color splatter (UCS). The UCS phenomena occurs when a developed image passes through a toner cloud created by a certain type of scavengeless development system. The forgoing problem is obviated by applying pressure to toner images in combination with recharging thereof prior to their passage through a developer housing.

Abstract: An electrostatic image forming apparatus has high cleaning efficiency using the electrostatic fur brush method. A photosensitive body having a photoconductive characteristic is charged uniformly. An electrostatic latent image is formed on the surface of the charged photosensitive body by radiating light rays on the area to be developed. The latent image is developed by the dry-type developing method by use of toner charged with same polarity as that of the photosensitive body's surface. The obtained visible image is transferred electrostatically onto the transfer paper. A non-electrically-insulative fur brush 16 removes the remaining toner 20 from the surface of the photosensitive body 14 and an electric potential gradient generator 17 generates an electric potential gradient through the fur brush which transfers the remaining toner 20 to the fur brush 16 from the surface of the photosensitive body 14. The toner to be employed has a substantially uniform particle diameter.

Abstract: In an image forming apparatus, a rotary developing device has a developing unit in which a plurality of developing chambers are arranged around an axis of rotation. The developing unit is rotated about the axis to bring one of the chambers to a developing position where an image carrier is located. In each of the chambers, part of a developer removed by a doctor blade is received by a guide and then released from the guide into the chamber. This part of the developer is agitated in the vertical direction and conveyed together with the developer existing in the chamber by the rotation of the device. As a result, the developer is agitated, conveyed and charged in a desirable manner.

Abstract: An image forming apparatus includes a plurality of toner reservoir for storing different toner, a developing unit composed of a plurality of developing devices, and a plurality of toner conveyors for conveying toner from the toner reservoir to the developing unit. Through-holes are formed in the developing unit, and an upper portion of each through-hole is connected with each toner conveyor in such a manner that an upper opening of each through-hole is opposed to an ejection port of each toner conveyor, so that toner drops from the toner conveyor into through-hole and is guided to each developing device.

Abstract: In a wet-type electrophotographic image formation method using an organic electrophotographic photoconductor constituted of an electroconductive support and a photoconductive layer formed thereon, the steps of (1) forming a latent electrostatic image on the photoconductive layer, and (2) developing the latent electrostatic image to a visible toner image with a developer comprising toner particles and a carrier liquid constituted of or including a silicone oil in which the toner particles are dispersed.

Abstract: Toners comprised of a mixture of a cyan toner, a magenta toner, a yellow toner, and a black toner each of said toners being comprised of resin and pigment, and wherein the pigment for the cyan toner is a .beta. type copper phthalocyanine, the pigment for the magenta toner is a xanthene silicomolybdic acid salt of Rhodamine 6G dye, the pigment for the yellow toner is an isoindoline, and the pigment for the black toner is carbon black.

Abstract: An apparatus for transferring toner images which is capable of executing optimum discharging control even where the environment, the material of the paper, and the kind of paper may be changed.First, the load current is detected when the transferring roller 11 is pressed to a transferring drum 6. The detected load current is converted to a characteristics detecting signal S6 at a signal converting section 109. An environment is selected on the basis of the characteristics detecting signal S6. Next, the load current flowing to the transferring roller 11 is detected when an AC discharger 14 is stopped. The detected load current is converted to characteristics detecting signal S6 at the signal converting section 109. A voltage control signal is selected based on the converted characteristics detecting signal S6, the environmental information, and the paper kind. A power source for discharging 22 is controlled by the selected voltage control signal so that the transferring becomes optimum.

Abstract: A printing system using a recharge, expose and development image on image process color system is disclosed in which there is an optional extra black development step. The printing system may be a single pass system where all of the colors are developed in a single pass or a multi-pass system where each color is developed in a separate pass. The additional black development step results in optimal color quality with black toner being developed in a first and/or last sequence. Having more than one black development station allows low gloss and high gloss black toner to be applied to the same image, enabling the very desirable combination of low gloss text and high gloss pictorials on the same page.

Abstract: In an apparatus in which a yellow, magenta, and cyan toner images are superimposed on a photoreceptor drum made of a transparent material, an image exposure device is provided in the photoreceptor drum and emits exposure lights whose wavelength has a spectral reflective ratio lower than 30% for at least two of yellow, magenta, and cyan toners. The image forming processes is controlled so that a toner image for which the exposure lights have a spectral reflective ratio larger than 30% is formed after toner images for which the exposure lights have a spectral reflective ratio lower than 30% have been formed.

Abstract: A color printer includes an electrophotographic process unit for selectively exposing the photosensitive image carriers to form identical latent images thereon, developing the latent images as toner images by supplying toners of different colors, and transferring the toner images onto paper, and a control circuit for controlling amounts of exposure of the latent images to be formed by the electrophotographic process unit. Particularly, the control circuit includes a toner-save key for selecting a toner-save mode, and processing circuit for lowering the exposure amounts of the latent images in the toner-save mode, while changing a rate of the exposure amounts to compensate for a difference between development properties of the toners.

Abstract: In a multi-color imaging apparatus utilizing a recharge step between two image creation steps for recharging a charge retentive surface to a predetermined potential pursuant to forming the second of the two images, a first corona generating device recharges the charge retentive surface to a higher absolute potential than a predetermined potential, and then a second corona generating device recharges the charge retentive surface to the predetermined potential. An electrical charge associated with the first image is substantially neutralized after being recharged by the first and second corona generating device.

Abstract: Toners comprised of a mixture of a cyan toner, a magenta toner, a yellow toner, and an optional black toner, each of said toners being comprised of resin and pigment, and wherein the pigment for the cyan toner is a .beta. type copper phthalocyanine, the pigment for the magenta toner is a quinacridone, the pigment for the yellow toner is a diazo benzidine, and the pigment for the black toner is carbon black.

Abstract: A toner cartridge in use with an image forming apparatus such as a printer. The toner cartridge includes a cylindrical container for accommodating toner, and the cylindrical container further includes; an opening at one side for discharging the toner accommodated in the cylindrical container; an spiral protrusion, provided on an inner circumferential surface of the cylindrical container, for conveying the toner toward the opening in the cylindrical container and for discharging the toner from the opening to outside the cylindrical container when the cylindrical container is rotated on an axis by a driver of the image forming apparatus; and a scoop, attached to the opening, for scooping the toner so that the spiral protrusion discharges the toner from the opening when the opening is at a position upper than a horizontal line extended through the axis.

Abstract: A patch image is formed on the photoreceptor under a patch image forming condition which is different from a recording image forming condition. The recording image forming condition is controlled by adjusting at least one of a charging device, a developing device and an electric bias in accordance with the density of the patch image.