Abstract: A color tranparency having high density includes overlying color toner images on opposite sides of a transparent substrate. The color images are formed by first forming two sets of electrostatic images, one set being a mirror image of the other. The electrostatic images are toned by application of different color toners to the images of each set and then each set is transferred in registration to opposite sides of the transparency.

Abstract: A method and apparatus for managing the storage of image data in a framestore of an electronic color printing system so as to minimize the storage requirements of the framestore. In such a system, image data is read out from the framestore in a color-separated sequence (R1-Rn; G1-Gn; B1-Bn) which differs substantially from a color-integrated sequence (R1,G1,B1-Rn,Gn,Bn) in which image data is received by the framestore from an input image scanner. According to the invention, values representing such color-integrated data from the image scanner are stored at address locations in the framestore vacated by the immediately preceding data read-out step. Such data management obviates the need for two separate framestores, each being capable of storing a sufficient number of multiple color-separated images to produce a desired array of multicolor images on a single receiver sheet.

Abstract: A color printer includes a recording element which is advanced along a path to receive color-separation images of a desired multicolor image to be printed. Color-separation image recording is effected by a laser scanner which operates asynchronously with respect to the movement of the recording element and functions to periodically scan an intensity-modulated beam of radiation across the moving recording element to record a multitude of equally spaced image lines that collectively define a two-dimensional latent image. In response to a print enable signal, the laser scanner begins scanning the first line of a color-separation image at any time within a line-time interval required to scan each image line. According to a preferred embodiment of the invention, the print enable signal is provided a predetermined fraction of the line-time interval earlier for the second and subsequent color-separation images of a desired multicolor image than it is for the first color-separation image.

Abstract: A variety of sizes of prints are made electrophotographically utilizing a single large size receiving sheet, for example, a receiving sheet that is 12.times.18 inches. The receiving sheet is large enough to receive one image of the largest size or an array of smaller sized images. The receiving sheet with smaller images is cut to size after transfer. The method is particularly useful in forming multicolor images on a receiving sheet wrapped around a transfer drum.

Abstract: An electrostatographic color image production apparatus forms a series of large color separation electrostatic latent images of a multicolor image on an image member. Each large latent image is made up of an array of smaller latent images with border regions therebetween. Latent images are formed in the border regions to create a border color in one of the dominant colors of the multicolor image.

Abstract: A color printing apparatus forms a series of electrostatic images on an image drum, tones them with different color toners and transfers the toner images to a receiving sheet to form multicolor images. The beginning and end of transfer of each image create mechanical discontinuities in the motion of the drum because of engagement and disengagement of the receiving sheet or its edges in a pressure transfer nip. The image-forming process is designed so that significant image scanning does not occur during the discontinuities.

Abstract: Multicolor toner images are formed on a receiving surface by superimposing single color toner images formed electrostatically on an image member, in registration on a receiving surface. The receiving surface is rotated by a transfer member, for example, a transfer drum, repeatedly through transfer relation with the image member. To improve transfer and avoid wear of the image member, the transfer member is driven by the image member during transfer. To improve registration the transfer member is separated from the image member between transfers and reindexed. A stepper motor is used for such reindexing. The invention is particularly usable in transfers using heat, especially to a heat softenable outer surface of a receiving sheet.

Abstract: A variety of sizes of color prints are made electrophotographically utilizing a single large size receiving sheet, for example, a receiving sheet that is 12.times.18 inches. The large size receiving sheet can be secured to a transfer roller to be cycled through the repeated single color transfers. The receiving sheet is large enough to receive one multicolor image of the largest size or an array of smaller sized multicolor images. The receiving sheet with smaller images is cut to size after transfer.

Abstract: Image frame length control apparatus and methods are disclosed which have particular utility in a printing or reproduction apparatus that writes one or more images on a transported photosensitive media such as a photoconducting drum or continuous-loop web. When an electronic writing system or optical exposure system is used to expose a driven media on a line-by-line basis, a variation in media thickness causes the latent image frame to be written with an inaccurate frame length. Consequently, a degraded print is produced.The latent image frame length is corrected during exposure, by adding or omitting one or more lines in the image frame. Alternatively, the exposure of an image is offet by an interval corresponding to one-half of the total length discrepancy between the uncorrected image frame length and the image frame length that would be written if the media surface speed was at a median level.

Abstract: Web tracking apparatus and methods are disclosed having particular utility in electrostatographic reproduction apparatus. A web includes a plurality of image frames allowing images to be written thereon and transferred therefrom to a receiver. A guide means moves such web along a path and includes a steering roller mounted for rotation about a caster axis and a gimbal axis. A web tracking system for controlling the guide means to effect lateral alignment of said web is provided such that the deviation of corresponding points of transferred images is minimized. Degradation of image registration due to mid-print corrections is eliminated and steering corrections are made less frequent by the use of adaptive and predictive algorithms. The writing and transfer of images is thereby accomplished in accurate registration and is particularly well-suited for use in forming accurate multicolor reproduction of superimposed images.

Abstract: A reproduction apparatus has an endless web with perforations or other indicia triggering image formation and receiving sheet presentation. To correct for error in perforation location the distance between perforations is measured and a delay after sensing one or both perforations is adjusted accordingly. Preferably, the distance between perforations is measured by an encoder temporarily connected to the apparatus when a new web is installed by a serviceperson.

Abstract: Endless web laser printer having enhanced copy registration. Compensation is made for the position of the laser beam along the scan line when the image scanning is to begin. The extra delay in starting the image scan is translated to an equal and extra delay for feeding the paper to the image transfer station. Up to one full line of misregistration can be corrected. Dividing the scan line into segments decreases the possible number of extra delay time quantities consistent with the perceivable improvement in registration tolerance.

Abstract: The specification discloses apparatus by which multiple reproductions can be produced from an original, all reproductions from the same original being of substantially identical quality. An electrographic machine substantially uniformly charges an electrographic recording member to a predetermined initial voltage and imagewise exposes the charged recording member at a nominal exposure level to produce a latent charge image. The initial voltage level and the exposure level are process control parameters of the machine, which also includes a biased electrode for controlling deposition of toner to the latent charge image. Signals are produced and stored having values characteristic of (1) the level of at least one of the parameters and (2) the bias voltage level which are associated with a desired reproduction quality of an original.