Abstract: An image forming apparatus is provided that forms an image with liquid developer, and a method thereof. The image forming apparatus includes a plurality of photoconductors on which developer images having carrier rates different from each other are formed with corresponding liquid developers. An image transfer member is disposed to form transfer nips with the respective photoconductors in such a manner that the developer images of the respective photoconductors are overlappingly transferred onto the image transfer member according to a transfer order predetermined on the basis of the carrier rates thereof. The developer images from the respective photoconductors are moved to an image receiving medium.

Abstract: An electrophotographic image forming apparatus includes first and second photosensitive bodies, first and second exposing units to form electrostatic latent images on the first and second photosensitive bodies each of which being charged to a uniform electric potential, a first developing unit to develop the electrostatic latent image on the first photosensitive body by supplying a transparent toner thereto, and a second developing unit to develop the electrostatic latent image on the second photosensitive body by supplying color toners thereto, wherein the first developing unit is a developing unit employing a two-component developing technique using a magnetic carrier and a transparent toner.

Abstract: The invention provides an imaging system wherein toners of two or more colors are used to form toner images and the toner images are successively used to form a color image on a recording material. The imaging system can form an image with high transfer efficiency. An electrostatic latent image is formed on an image carrier. Using developing units for two or more colors, images are formed. Then, the images are successively transferred onto an intermediate transfer medium at a transfer voltage fed from a constant-voltage power supply. The developing units are located such that development occurs in descending toner work function order.

Abstract: Images based on each of a plurality of color components are formed; the formed images are transferred on each transfer medium to form an image quality determining image; the image quality of the image quality determining image is determined on the basis of the detected density thereof, an adjustment image is formed by overlaying and transferring an image of other color component to be adjusted to the reference image of the reference color image out of the plurality of color components, on the transfer medium; the density of the adjustment image is detected; and the image forming position of the other color component to be adjusted is adjusted on the basis of the detected density.

Abstract: Each of a plurality of combined images is formed separately for each image carrier with respect to a length related to the circumference length (Dp×?) of the image carrier. There is provided a combined-image adjusting section for forming a combined image so that a density detecting section detects the density of the combined image at plural and substantially equal pitches within a range of at least one circumference length (Dp×?) of the image carrier, or so that the density detecting section detects the density average value of the combined image at plural and substantially equal pitches within a range of at least one circumference length (Dp×?) of the image carrier.

Abstract: The selective depopulation and/or repopulation of a full color image-next-to-image or image-on-image print engine for generating monochrome and/or highlight color images, utilizing a multiplicity of functionally-equivalent substations in tandem to compensate for the increase in printing speed.

Abstract: An electrographic printer device contains a first printing unit and a second printing unit, each printing unit containing at least one developer unit. A second developer unit in the second printing unit employs a coating method that works without contact, for example the toner spraying method, and inserts colored toner images into toner-free regions on the photoconductor drum.

Abstract: Assuming the photosensitive drum for black as a reference, the phase of the adjacent photosensitive drum for cyan leads by about 60 deg. Similarly, the phase of the photosensitive drum for magenta leads by about 120 deg., and the phase of the photosensitive drum for yellow leads by about 180 deg. The phase of each photosensitive drum is shifted to thereby make it possible to shift the phase of driving unevenness. By shifting the phase, even the distance between adjoining transfer positions corresponding to the image forming stations is set shorter than the circumference of the photosensitive drum, the variation of each photosensitive drum due to driving unevenness with respect to the printing medium passing through the transfer position can be kept congruent with the others.

Abstract: A method and apparatus for an electrophotographic color printer. The method of developing a color image onto a photoconductor includes providing a single base charge to the photoconductor and then using a cascade of developer potentials for the toners in the process such that earlier applied toners are at higher electrical potentials than are later applied toners. Consequently, the latter applied toners will not tend to migrate to the previously developed sections. Additionally, the method includes applying color toners in the sequential order of black, cyan, magenta (or magenta, cyan), and yellow. In this manner, any contamination of previously applied toner by later applied toner will be less evident. An apparatus for performing this cascading color printing method is also disclosed. The invention further includes an apparatus for performing four-beam laser scanning of a photoconductor using a single rotatable, polygonal-sided mirror and as few as one laser.

Abstract: In the particular embodiment disclosed in the specification, an electrostatic image forming arrangement includes a photoreceptor in the form of a continuous belt which is moved past four development stations each containing a different colored toner which incorporates ferromagnetic material. At each development station a developer roll conveys toner in closely spaced relation to the surface of the photoreceptor and a DC-biased AC voltage is applied to the developer roll to cause the toner to be transferred to an electrostatic image on the photoreceptor. A magnet member mounted on the opposite side of the photoreceptor produces a magnetic field which holds toner on the image-receiving surface permitting a greater range of variation for the DC-biased AC toner transfer voltage.

Abstract: An electrophotographic imaging system produces multiple gray level images and includes a photoconductor and a charger for repetitively charging the photoconductor to a first charge potential. A laser system selectively discharges the photoconductor in accord with applied image data. A first toner is utilized and exhibits a first charge state that is attracted by a first discharge voltage of the photoconductor. A second toner is also used that exhibits a second charge state of the same sense as the first toner, but is attracted by a second discharge voltage of larger magnitude than the first discharge voltage. A processor modulates the laser system to cause the photoconductor to be discharged to the first discharge voltage when only the first toner is to be attracted to the photoconductor. The processor further modulates the laser scanner to cause the photoconductor surface to be discharged to the second discharge voltage.

Abstract: The image forming apparatus includes: an image forming portion having a multiple image forming stations each forming a color separated image; a transfer device for superimposing and transferring color separated images; a pattern image forming device for forming a predetermined pattern image; a pattern image density measuring device for measuring the density of the pattern image. In this configuration, the pattern image is formed so as to be greater than the measuring area of the pattern image density measuring device and is formed of multiple lines having a line width and a line spacing so that any part of the pattern image within the measuring area will produce an approximately constant measured density value.

Abstract: A color image processing system for performing undercolor removal. The system includes input of a color image signal, generation of a grayness signal from the color image signal, generation of a darkness signal from the color image signal, and performance of undercolor removal based on the grayness signal, the darkness signal, and a black signal corresponding to the color image signal. The system also includes control of an amount of undercolor removal performed on the color image signal so that a gradient of an amount of undercolor removal performed on the color image signal relative to the grayness signal at a first darkness signal level is lower than a gradient of an amount of undercolor removal performed on the color image signal relative to the grayness signal at a second darkness signal level, wherein the second darkness signal level is lower than the first darkness signal level.

Abstract: A color electrophotographic printer that prepares a composite toner image for transfer by exposing an image area containing the composite toner image to an erase lamp and then running the composite toner image by an AC scorotron.

Abstract: An electrophotographic machine has a photoreceptive member supporting a composite color toner image formed of multiple layers of different colored toners. The composite toner image is pre-transfer charged at a first voltage level and recharge at a second voltage level less than the first voltage level. The background toner is preferentially charged by the second charging to reduce transfer of the background toner to the substrate.

Abstract: A composite toner image made up of first and second toners is formed on an image member. A first electrostatic image of a first polarity is formed on the image member. That electrostatic image is toned with a first toner of the first polarity. The image member is imagewise exposed to create a second electrostatic image also of the first polarity. Exposure is overlapped into the portion of the image member under the first toner image to prevent any charge on the photoconductor of the first polarity underneath the first toner image from repelling toner into the portions of the second electrostatic image that are discharged. Preferably, the second exposure is accomplished through the base of the image member in order to thoroughly expose portions of the electrostatic image underneath the first toner image.

Abstract: A method of, and image-forming device for, forming at least two toner images in register on a rotatable charge retentive medium. To that end, within one revolution of the charge retentive medium, the method: applies a first charge image according to a first image; develops a first toner image in accordance with the first charge image on the charge retentive medium by applying a first unary electrically conductive and magnetizable toner, e.g., via a first magnetic brush; applies a second charge image according to a second image; and develops a second toner image in accordance with the second charge image on the charge retentive medium by applying a second unary electrically conductive and magnetizable toner, e.g., via a second magnetic brush. The toner should have an electrical conductivity between 1 and 10.sup.-7 (ohm.cm).sup.-1.

Abstract: An electrostatographic method and apparatus of forming a toner image on a receiver. In order to improve transfer of a pigmented toner image to a receiver, a clear toner layer is applied to a support member. The pigmented toner image is applied over the clear toner layer. The pigmented toner image is sintered and the sintered pigmented toner image is then transferred to a receiver sheet.

Abstract: A Recharge-Expose-and-Develop Image on Image color electrophotographic printing system in which the photoreceptor is recharged between development of one color of toner image and the subsequent exposure for a second color latent image by first being sprayed with opposite sign ions to reduce the photoreceptor potential and then being charged with correct sign ions to recharge the photoreceptor to a desired potential.

Abstract: A method and apparatus for minimizing image banding and for registering multiple image planes of a single image on a receptor drum in electrographic systems. The system for registering multiple image planes of a single image in an electrographic system includes a receptor drum capable of capturing two or more overlaying image planes, an exposure device for forming overlaying image planes on the receptor drum, and at least one developer station transferring a developer to the receptor drum corresponding to each of the overlaying image planes. A measuring device is provided for measuring the rotational position of the receptor drum. A drive mechanism is provided for controlling a motor coupled to the receptor drum by at least one drive belt. A closed loop positioning system is coupled to the measuring device and the drive mechanism. The closed loop positioning system is capable of modulating the angular velocity of the receptor drum to achieve image plane registration of the two or more image planes.

Abstract: A method and apparatus for eliminating undesirable development of background charge potentials in a multicolor electrostatographic system is disclosed, wherein the application of a developer bias at a given development station is selectively controlled to be substantially equal to or greater than the background image voltage of the image generated by a preceding imaging station such that the voltage differential between toner particles at the development station and the background areas including the previous image areas is substantially zero and the electrostatic forces acting on the toner particles are insufficient to attract the toner particles to the residual image.

Abstract: A multistation color electrophotographic printer having an erase lamp located opposed to or before the last physical developer housing, but after the first physical developer housing.

Abstract: An image forming apparatus includes at least a first image-forming unit provided with a first latent image-holding member, a first latent image-forming device, a first developing device for developing a first latent image with a first toner to form a first toner image, and a first image-transfer device for transferring the first toner image to an image-receiving member, and a second image-forming unit provided with a second latent image-holding member, a second latent image-forming device, a second developing device for developing a second latent image with a second toner to form a second toner image, and a second image-transfer device for transferring the second toner image to the image-receiving member holding the first toner image. The second developing device also serves as a cleaning device for recovering the toner remaining on the second latent image-holding member after the transfer to perform cleaning.

Abstract: A color REaD IOI system in which a light source illuminates the photoreceptor so as to erase that photoreceptor after the development of black toner but before exposure and development of the next color image.

Abstract: A color REaD IOI system in which the photoreceptor is DC only recharged between the development of the first toner layer and the subsequent exposure and development of the following toner layer. To assist the DC only recharge the photoreceptor and the first toner layer are beneficially erased prior to recharge. Beneficially, the photoreceptor is subsequent recharged prior to exposures for the other toner layers using a charging scheme that includes an AC charging device.

Abstract: A color REaD IOI system in which a light source illuminates the photoreceptor so as to erase that photoreceptor after the development of a first toner followed by a high slope AC corona system which recharges both the photoreceptor and first developed toner before exposure and development of the next color image.

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: An image forming apparatus includes a photosensitive member; a charging member for charging the photosensitive member; an exposure device for exposing an image formation area of the photosensitive member charged by the charging member to light in accordance with an image signal to for an electrostatic image, and for exposing non-image-formation area around the image formation area to spots of light; and a developing device, having a developer carrying member for carrying a layer of developer having a thickness smaller than the gap with which the developer carrying member is opposed to the photosensitive member, for effecting reverse development of the electrostatic image.

Abstract: A color image forming apparatus includes a drum type image forming body; four charging devices for charging the image forming body; four exposure devices fixed on the main body for imagewise exposing the charged image and forming body to form a latent image; four developing devices each for developing the latent image to form a different colored toner image. After operations by the charging devices, the exposure devices and the developing devices are repeated to superimpose the different colored toner images on the image forming body, the superimposed colored toner images are transferred by a transfer device including an intermediate transferring member and a transfer member in contact with the intermediate transferring member onto a recording material at one time.

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 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: In a color image forming apparatus, as the second and subsequent development processes of the simultaneously transfer type, a non-contact type AC field double-element development is employed, and an absolute value of the difference between the maximum bias which provides the maximum toner developing electric field in the direction to the side of the latent image carrier and the average value of the developing bias is set larger than an absolute value of the difference between the minimum bias voltage which provides the minimum toner developing electric field in the direction to the side of the latent image carrier and the average value of the developing bias, while the bias voltage region located between the maximum bias voltage and the average bias voltage is set to a ratio of from 0.25 to 0.45 for one period of the AC voltage, and the frequency of the bias voltage is set from 4 kHz to 10 kHz.

Abstract: An image forming apparatus includes at least two developing units containing two types of developing agents of different colors. This image forming apparatus is improved in the following points. i) The triboelectric charging amounts of the toner of the developing agents are reduced in the order of transfer. ii) The volume resistivities of the developing agents are reduced in the order of transfer. iii) The charging potentials of image carriers when electrostatic latent images corresponding to individual developing agents are formed are reduced in the order of transfer.