Abstract: The present invention is a method of adjusting a color in a color proof (112) printed with primary colors cyan, magenta, yellow, and black.

Abstract: The invention relates to an apparatus for printing a multibit per pixel image (10) from a halftone binary digital bitmap having pixels having a multibit per pixel image memory for receiving the multibit per pixel image; a lookup table (16) external to the memory disposed in a programmable gate array (18) for converting the multibit per pixel image to a base duty cycle (20) wherein the base duty cycle is disposed in the programmable gate array and is adapted for creating a modulated drive signal (22) from the base duty cycle to modulate an exposure (24) for each pixel in the multibit per pixel image; and a printer (28) adapted for using the modulated exposure to print an image, having a dpi greater than 1400, further comprising a drum (32) capable of spinning, and an encoder (34) disposed on the drum for providing a home signal (36) and a pixel rate (38).

Abstract: An image processing apparatus (10) comprises an imaging drum (300) for holding print media (32) and donor material (36) in registration on the imaging drum (300). A print head (500), driven by a lead screw (250) and stepper motor, moves along a line parallel to a longitudinal axis (X) of the imaging drum (300) as the imaging drum (300) rotates. The print head (500) is brought repeatably to a mechanical registration position using sensors. For coarse positioning, the print head (500) is moved to a first linear sensor position, with the drive motor operated in full-step mode. For fine positioning, the drive motor is then operated in microstepping mode, during which a second sensor detects rotational orientation by detecting a rotational indicator mounted on the lead screw (250). The rotational indicator permits straightforward adjustment for fine-tuning, being adjustable to any one of a number of fixed positions relative to lead screw rotation.

Abstract: A laser diode controller (30) having a constant current source (60) which supplies current to a laser diode (90) is disclosed. A current shunt switch (40) directs current to either the laser diode (90) or to a bypass circuit (42). A thermal compensator (70) alters a current level of the constant current source (60) as a function of on-time of the laser diode (90) to compensate for changes in optical power conversion efficiency due to temperature changes in the laser diode. A thermo electric cooler controller (80) maintains a constant temperature of a substrate on which the laser diode is mounted. In one embodiment, an array of sample and hold amplifiers (50) eliminates a need for multiple DACs.

Abstract: A structural polymeric composite containing corn-based material is provided. In one embodiment, a polymeric composite is a laminated polymeric composite that contains a fibrous component of corn. A method of making a structural composite using corn-based material is also provided.

Abstract: A multiple-source array for use in thermal printing uses source interleaving to avoid overlapping of the dye-transfer tracks upon the donor material in a single pass. This prevents the formation of artifacts in the image because of thermal interaction among either the sources or printing spots. This also permits the thermal array to be oriented predominantly perpendicular to the first-scan direction so that any arcuate shape of the array causes minimal spacing variations of the scan lines and minimizes spacing variations in focus for laser-thermal printing or document source separation for resistive-head thermal printing. Interleaving also allows multiple printheads to be used even when they have different printing characteristics. The array includes independently addressable printing element data channels and a data distributor allowing interleaving to be accomplished in the printhead.

Abstract: A multiple-source array for use in thermal printing uses source interleaving to avoid overlapping of the dye-transfer tracks upon the donor material in a single pass. The array includes independently addressable printing element data channels and a data distributor allowing interleaving to be accomplished in the printhead. The printhead also includes pixel replication circuitry that allows pixel replication in both the fast and slow scan directions.

Abstract: A method and apparatus for operating a laser diode array in a laser thermal printer, wherein the laser diodes are formed on a common substrate, includes: generating digital image data signals for the individual diodes in the array; generating correction signals for each diode in the array, the correction signals being generated by weighting selected digital image data signals; summing the weighted correction signals with the digital image data signals for each diode in the array to produce control signals; employing the control signals to produce a driving current for each diode in the array; applying the driving currents to the diodes in the array.

Abstract: A thermal printer is capable of printing proofs of images on a receiver with any of a plurality of selected half-tone dot patterns. The proof image is generated with a series of incremental dots. A plurality of the incremental dots are generated substantially simultaneously as a swath. The image is formed as a composite of a plurality of the swaths. The printer has the capability of printing with various swath widths. The swath width for a particular image is selected to preclude visible beating of the incremental dots against the selected half-tone dot pattern. Any image artifacts which are a product of interaction of the selected half-tone dot pattern and image elements (such as picket fences) are properly illustrated on the proof image. Image artifacts that are the product of interactions of the incremental dots and the half-tone dots are made invisible to the human eye.

Abstract: A method is disclosed for the calibration of a multichannel printer. The printer comprises a plurality of diode lasers which are modulated in accordance with an information signal. Radiation from the diode lasers is imaged onto a receiving medium such as a thermal print medium. The thermal print medium is supported on a drum which is rotatable about an axis. In order to balance the output from the diode lasers, test patterns are formed on the receiving medium with each of the lasers using known power inputs. The density of each of the test patterns is measured, and the density values obtained are correlated with the input power levels for each of the lasers. The measurement of densities produced by a single laser is facilitated by slowing the print head down by a factor of the number of lines normally printed and writing with one line source at a time.

Abstract: A method and apparatus are disclosed for scanning a receiving medium. The apparatus comprises a motor-driven lead screw which is used to advance a print head relative to a receiving medium supported on a rotatable drum. In order to overcome the problem of banding in an image produced by the apparatus as a result of a sinusoidal pitch error of the lead screw, the pitch error of the lead screw is broken up into a random pitch error. In another embodiment, the pitch error frequency is shifted to a higher frequency which is less sensitive to the human eye.

Abstract: A method and apparatus are disclosed for the calibration of a multichannel printer. The printer comprises a plurality of diode lasers which are modulated in accordance with an information signal. Radiation from the diode lasers is imaged onto a receiving medium such as a thermal print medium. The thermal print medium is supported on a drum which is rotatable about an axis. In order to balance the output from the diode lasers, test patterns are formed on the receiving medium with each of the lasers using known power inputs. The density of each of the test patterns is measured, and the density values obtained are correlated with the input power levels for each of the lasers. The measurement of densities produced by a single laser is facilitated by slowing the print head down by a factor of the number of lines normally printed and writing with one line source at a time.

Abstract: A thermal printer is disclosed which is a adapted to form an image on a thermal print medium of a type in which a donor element transfers dye to a receiver element upon receipt of a sufficient amount of thermal energy. The printer includes a plurality of diode lasers which can be individually modulated to supply energy to selected dots on the medium in accordance with an information signal. The print head of the printer includes a fiber optic array having a plurality of optical fibers coupled to the diode lasers. The thermal print medium is supported on a rotatable drum, and the fiber optic array is movable relative to the drum. In order to prevent banding in an image produced on the print medium, the two outside fibers in the array are used for preheating and postheating of inner scan lines. The printer is particularly well adapted for use as a proof printer for half-tone reproductions of images.

Abstract: There is disclosed a method for providing precise color-to-color registration of color dots in a multicolor proof with a thermal printer comprising a CPU and Printer Controller, a Motion Controller, a writing drum, and a writing head coupled to a translation means. Using the disclosed method, a proof and a dye donor member with a predetermined dye color thereon are mounted on the writing drum. The writing head is then moved to a predetermined start position defined by a sensor at a predetermined position along the translation means which has its optical path blocked by the writing head. The writing head is then moved forward to a predetermined home position which is defined by a next subsequent pulse from a multi-pulse radial position-indicating encoder coupled to the translation means occurring after the writing head leaves the start position.

Abstract: The present invention relates to thermal printers including a thermal print head mounting a plurality of N thermal heating devices such as lasers or resistive heating elements. In the thermal printer, a receiver member is mounted on a rotating drum with a dye carrier member engaging the outer surface of the receiver member in a dye frame image printing area. The thermal heating devices are aligned at a predetermined acute angle .THETA. to a line normal to the rotation of the drum. During the high speed rotation of the drum, the thermal heating devices are selectively energized by micropixel clock pulses which are synchronized to the rotational speed of the drum. During each rotation of the drum, N columns of micropixels are printed on the receiver member. Additionally, the energizing of each of the thermal heating elements is timed using the micropixel clock pulses so as to print corresponding micropixels of the N columns of micropixels in a line normal to the rotation of the drum.

Abstract: There is described a simple and inexpensive circuit for a thermal printing system which provides various test and diagnostic image patterns. The circuit includes a dual-port RAM, an address counter, a handshake logic unit and a multiplex switch unit. The image patterns provided by this circuit, which are applied to the printing system at high speed and in real time (e.g., 10 m bits/sec.), visually verify the precise mechanical and electrical adjustment, normal operating performance, and the high quality print output of the overall printing system. Various test images are easily programmed off-line into this electronic circuit. This circuit, with its printed test images, provides a highly useful tool in the initial set-up and the subsequent maintaining of the operation of the printing system.

Abstract: A thermal printer is disclosed which is adapted to form an image on a thermal print medium of a type in which a donor element transfers dye to a receiver element upon receipt of a sufficient amount of thermal energy. The printer includes a plurality of diode lasers which can be individually modulated to supply energy to selected dots on the medium in accordance with an information signal. The print head of the printer includes a fiber optic array having a plurality of optical fibers coupled to the diode lasers. The thermal print medium is supported on a rotatable drum, and the fiber optic array is movable relative to the drum. In order to prevent banding in an image produced on the print medium, the two outside fibers in the array are used for preheating and postheating of inner scan lines.