Abstract: Unexpectedly good transfer of electrophotographically-produced images using small toner particles occurs when the image is developed on an electrostatographic recording member, preferably an organic photoconductive element, which has been overcoated with a thin (about 10 nm to about 10 .mu.m thick) layer of a material having a Young's modulus greater than 10 GPa and preferably greater than about 100 GPa. The image is then transferred to an intermediate member which is comprised of an elastomeric blanket between about 0.1 and about 3 cm thick, having a Young's modulus between about 0.5 MPa and about 50 MPa, and preferably between about 1 and about 10 MPa, and having an electrical resistivity between about 10.sup.6 ohm-cm and about 10.sup.12 ohm-cm, by applying an appropriate electrostatic potential between the transfer intermediate member and the photoconductive element.

Abstract: The process control method for a DAD-CAD image forming method includes forming a DAD electrostatic image of a first polarity and applying toner of the first polarity to form a first toner image and then forming a CAD electrostatic image. To provide ample voltage for formation of the CAD image and to reduce scavenging, the development completion of the first electrostatic image is preferably kept below 0.4, preferably by reducing pole transitions provided by a rotatable magnetic core in toning the first image. The process is further controlled by adjusting an initial charge on the image member which also can be trimmed after formation of the first image by a uniform light exposure and by adjustment of AC biases in both toning steps.

Abstract: A method and apparatus for electrostatically transferring a toner image from a toner image bearing member to a receiver sheet is disclosed. A receiver sheet is moved within a nip defined between a transfer roller having a resistive outer layer and a toner image bearing member supporting a toner image. To provide for transfer, there is applied to the resistive layer a first contact voltage to establish a post-nip electrical voltage distribution to a post-nip region of the transfer roller that is immediately downstream of an in-nip region. The post-nip electrical bias is accomplished by having the first contact voltage be applied at first points on the outer layer of the transfer roller, the first points being within or proximate the post-nip region. There is also applied to the resistive layer a second contact voltage to establish a pre-nip electrical voltage distribution to a pre-nip region of the transfer roller immediately up-strean of the in-nip region.

Abstract: A stack of sheets, which sheets have different characteristics on their two sides, is marked on an edge of the stack with markings to prompt the user to properly orient the stack.

Abstract: First and second toner images are formed electrophotographically on first and second photoconductive imaging members, respectively. The first toner image is transferred to the second photoconductive image member in registration with the second toner image to form a combined toner image which may be in two colors. To improve the transfer between the two photoconductive image members, at least one of the photoconductive image members is preferably compliant.

Abstract: The scavenging of a first toner into a second toning station in a DAD-CAD or CAD-DAD process can be reduced by allowing scavenged toner to deposit in the background of single color images. The polarity of the first toner of the scavenged toner is not changed prior to transfer and remains on the image member through transfer from which it is later cleaned. Alternatively, scavenged toner is deposited from a second toning station on the image member while no images are being made and allowed to pass through transfer to be cleaned off.

Abstract: A method of developing electrostatic images with a two component developer avoids the break-in period of developer by providing a fresh mixture of carrier and toner, which toner has a first particle size but replenishes the mixture in use with toner having a second particle size larger than the first particle size. This compensates for the tendency of electrostatic images to preferentially attract the larger particles in a toner mixture.

Abstract: A transfer member includes separately addressable electrodes separated from the surface of the member by a compliant layer. Preferably, the member is an intermediate transfer member having a thin, hard outer layer usable to receive toner images from an image member and to transfer them to a receiving sheet.

Abstract: First and second toner images (usually of different color) are formed which at least partially overlap. The first toner image is crated by electronically exposing, pixel-by-pixel, a uniformly charged image member, to create a first electrostatic image and toning that image with toner of a first color. A second electrostatic image is formed by electronically exposing the image member according to a second electronic signal. The exposure of each pixel in the second exposure is adjusted to compensate for a change in electric field caused by any presence of toner from the first exposure in that pixel. The second electrostatic image is toned by toner of a second color to create a multicolor image with portions that overlap.

Abstract: A method for producing a calibrated printhead having a plurality of light-emitting recording elements such as LEDs includes the steps of (a) burning-in the recording elements until a further aging characteristic of the recording elements is in a generally linear range; (b) measuring a light intensity emitted by each recording element after the burning-in in step (a); (c) establishing a target value for additional burning-in of at least those recording elements having measured light intensities above a minimum measured light intensity for a recording element; and (d) respectively providing additional burning-in to those recording elements towards the target value. An apparatus including the calibrated printhead has no data provided to the printhead which is corrected for relative non-uniformity of the recording elements to each other.

Abstract: A copier/printer system includes an image scanner for scanning a document and providing, after a compression step, digital image scanning signals, P.sub.1, that may be communicated to a computer system for display and editing or alternatively communicated to a grey level printer having a magnetic tape memory. The computer system may be used to display the scanned image for editing by an operator and is coupled to the printer so that the edited image signals, P.sub.2, which may be the scanned signals and a common page description language to modify its usage, may be printed by the printer. The edited image signals, P.sub.2, may be sent to the printer over a suitable network. The printer includes image processing electronics for transforming the edited data, P.sub.2, into device independent data signals, P.sub.3. Such signals may be received by printers of the same type; i.e., those employing similar process and halftone algorithms. The signals, P.sub.

Abstract: A method and apparatus for reproducing an original image includes a scanner or other image source for generating a digitized raw image data for each pixel area of an image. For each pixel the raw image data is transformed into a gray level rendering value pixel by comparing the raw image data value with threshold values from threshold mask sets. Tone adjustment means is provided for generating a tone corrected rendering gray level pixel value for each pixel. A printer or display is controlled to print the digitized image signal by rendering the dot regions in accordance with the tone corrected gray level rendering pixel value. Thus after a print is made a tone correction adjustment maybe made and in response to this tone adjustment a new print can be made using rendering image data in buffer memory without the need for rescanning of the image.

Abstract: A dry toner image is fixed to a thermoplastic layer on a receiving sheet by pressing a ferrotyping web against the image in the presence of sufficient heat to soften the layer. A curl preventing layer opposite the thermoplastic layer does not offset on a backing roller or the like because it has a melting point that is high compared to the thermoplastic layer.

Abstract: A method and apparatus for processing image data of pixels to be rendered for efficient storage in a memory or efficient transmission wherein a grey level value of a rendered pixel is represented by multiple bits including a most significant bit (MSB) and a least significant bit (LSB). The method and apparatus provide for modifying of the density values of successive pixels in accordance with an error diffusion operation. The modified density values are then subject to a thresholding operation wherein the thresholding operation employs position of a pixel to determine the digital value of the LSB of the rendered pixel. There is thereby provided a pattern structure to the LSB data. The rendered pixel values may then be compressed to provide for efficient storage in a memory or for efficient transmission over a communication pathway.

Abstract: A non-impact printing apparatus and method for tri-level color xerographic recording. A binary printhead having M recording elements per inch is used to record each mainscan line (1/M lines per inch) of pixels using two sublines for recording each mainscan line. In a first embodiment, pixels to be developed in a first color are recorded during a first subline, and during a second subline of pixels to be developed in a second color are recorded using a different exposure duration from that used in recording the first subline of pixels. In a second embodiment, pixels of the first and second colors are recorded during a first subline and supplementary exposure is provided for completing the recording of pixels of the second color during a second subline of recording.

Abstract: In an electrostatographic process wherein images are formed on an electrostatic image supporting medium and developed by a development station having a developer formed of a mixture of toner and carrier particles, there is provided apparatus for controlling various processing control parameters in response to formation of a toned patch on the medium. The apparatus includes a first feedback controller that processes signals related to the parameter toning contrast in accordance with a closed loop control of this parameter. The first feedback controller serves as a toning contrast controller and outputs a first signal representing toner concentration set point in response to closed loop control of toning contrast. The apparatus also includes a second feedback controller means that is slaved to the first feedback controller and serves as a toner concentration (TC) controller.

Abstract: A gray scale printer is adapted to modulate an exposure source in both amplitude and duration in accordance with an eight-bit data signal. The printer provides for modulating the amplitude of the exposure source in accordance with the six least significant bits of the data signal, and for modulating the duration of the exposure source in accordance with the two most significant bits of the data signal. Amplitude modulation may effect electrical current to the exposure source, and the duration modulation may effect pulse width of electrical current to the exposure source. The exposure source may be, for example, a laser diode or a light-emitting diode array.

Abstract: An image forming apparatus uses an endless belt image member having a magnetic strip along one or more edges. A linear printhead is flashed in response to a magnetic encoder signal in the magnetic strip. Preferably, the apparatus has first and second linear writers and the magnetic encoding signal is created in the magnetic strip in conjunction with creation of a writing signal for the first writer with the second writer using the magnetic encoding signal to register its writing with the first writing. Preferably, an auxiliary signal is placed in the strip indicative of variable characteristics of either the image member or the image forming apparatus. This in turn is read by the apparatus and a charging, exposing or toning station controlled in response to the auxiliary signal.

Abstract: A method and apparatus for grey level printing includes a plurality of recording elements which are enabled for variable periods of time during a cycle of recording grey level pixels. For each recording element a comparator compares the count in a time-changing exposure counter with a multibit grey level data signal. The exposure counter is decremented/incremented by exposure clock pulses from a programmable exposure clock. The exposure clock includes a master clock and an address counter that provides an incremented address signal in response to each set of N pulses from the master clock. The address signal identifies a location in memory of a set of signals used to generate exposure clock pulses. The set of signals is output in parallel to a serial shift register and shifted out serially to form the exposure clock pulses for decrementing/incrementing the exposure counter.

Abstract: Transfer of a toner image from an image member to either an intermediate member or a receiving sheet is improved by irradiating a photoconductive layer in the image member during transfer. Erasing radiation is allowed to fall on both the in-nip region and a pre-nip region but is baffled from a post-nip region. The erasing radiation increases the time constant of the system thereby slowing the build-up of the field in the pre-nip region inhibiting pre-nip ionization. The lack of erasing radiation in the post-nip region decreases the time constant thereby speeding the reduction in the field and also reducing ionization in that region.