Abstract: This invention relates to an improved wide format color digital print engine, and in particular to a cooperating group of print engine sub-assemblies comprising a sealable enclosure defining electronics and printing sub-spaces within the enclosure and supporting two critical alignment plates which alone control alignment of all major sub-assemblies of the print engine and which provide accurate attachment points for a carriage drive and rail sub-assembly, a motor and drum mounted to rotate within a printing bay, and mounting points for a service station for cleaning and storing a plurality of marking elements associated with replaceable ink emitting cartridges. The subassemblies cooperate to generate high quality colored images as a drum-based large format digital ink jet print engine.

Abstract: A method calibrating a thermal print head printer having fixed imaging elements so that consistent high resolution output may be achieved includes a means for measuring a common characteristic of each fixed imaging element and storing the values so that print head compensation may occur during the printing process one scan line at a time. Error diffusion, either across the thermal print head, down-web, or both, ensures that appropriate drive level are supplied to each fixed imaging element regardless of inherent differences in the common characteristics of the fixed imaging elements, to achieve consistent tonal image quality. In a preferred embodiment, the fixed imaging elements are thin film electrical resistive elements and the common characteristic is the electrical resistance of the thin film resistor elements.

Abstract: A scanning head ink jet printer utilizes variable paper advance interlacing. The printer includes a plurality of heads each having a plurality of rows of uniformly spaced ink jets which print different colors. A printing medium is advanced in a series of non-uniform distances (d.sub.1, d.sub.2, d.sub.3, d.sub.4) the sum of which is equal to the total number of uniformly-spaced ink jets (n) of one of the colors times the uniform spacing (s) of one pixel row from an adjacent pixel row. In a specific embodiment, a total advance of the printing medium is equal to the total number of uniformly-serial spaced ink jets of one color is 48, the spacing is four pixels, and the non-uniform distances include 49, 49, 45 and 49 pixels.

Abstract: A hot melt ink jet printer capable of handling 54 inch media widths and printing at a minimum resolution of 300 dots per inch. The ink jet printer of the present invention includes a printing medium handling system for transporting the printing medium through the printer. The printing medium handling system includes a paper tensioning system for maintaining a constant tension in the printing medium as the printing medium is advanced past the print heads for imaging and also subsequently as the printing medium is post-image heated. A readable/writable memory unit accompanies the supply of printing medium and provides information indicative of the color characteristics, handling characteristics, and/or related characteristics associated with the printing medium for use by a controller at each important control point of the paper path.

Abstract: Output device command information and color description information are identified in a source image description and encoded into a pixel description packet. The source image description is converted into an arrangement of pixel data with each pixel location in the arrangement having a pixel description packet associated therewith. The pixel description packet is then decoded to determine output device command information and color information which is provided to an output device on a pixel-by-pixel basis for forming output pixels representative of source images.

Abstract: A high resolution thermal printer capable of printing both directly on a thermally responsive media and indirectly through a thermally responsive donor media is disclosed. The printer has a printing media guide mounted as an intermediate clamshell structure to accurately position the printing media immediately adjacent the print head and platen. The printing media guide includes a nip roller and guide bar independently suspended on a spring biased, pivot plate arrangement. The printing media is centered on the supply spool, and the printer includes a read/write circuit to communicate with a profiler chip centrally mounted in the printing media roll. The printer may also include a read/write circuit to communicate with a donor profiler chip centrally mounted in the donor media roll. A constant pressure brake with a friction belt is used directly against the printing media. A spring arm latch/channel block arrangement is used to secure the printing media supply spool.

Abstract: A driver circuit provides a plurality of drive energies having a plurality of thermal distributions associated therewith. These thermal distributions interact with print media to form binary images having active and inactive areas. A driver control circuit is responsive to source image information to apply selected drive energies to selected heating elements. These drive energies produce interacting thermal distributions for selectively positioning boundaries between active and inactive areas.

Abstract: A thermal printer includes a thermal print head having a plurality of heating elements for printing dots. A source of drive pulses operates respective heating elements. Each drive pulse is modulated to provide first and second periods of the drive pulse to selectively energize the respective heating element, the first and second periods defining a selected energy level. A memory stores the modulated drive pulses and supplies respective modulated drive pulses to the respective heating elements. A measuring circuit measures a heating factor of each heating element and provides a correction factor for each heating element based on the respective measured heating factor. The correction factors are combined to the respective drive pulses to alter the first and second periods, thereby reducing variations in dots due to differences in the heating factors of the heating elements.

Abstract: A network protocol facilitates high speed transmission of raster data from a server to a client. The protocol defines a first sub-protocol for negotiating a connection and preparing to transmit a print job, and a second sub-protocol for transmitting a large quantity of raster data. The second sub-protocol allows the recipient of the data to dictate the order in which various types of data are transmitted, while allowing for efficient error correction of lost and/or corrupted packets. In one embodiment, a server is configured to transmit data to a client using the protocol of the present invention. In another embodiment, a client is configured to receive data from the server according to the protocol of the present invention. The protocol minimizes handshaking by sending a large number of data packets between acknowledgements.

Abstract: A hot melt composition that comprises a color concentrate and a base component, the color concentrate comprising a colorant, and a hot melt ink concentrate that comprises a colorant, a non-wax colorant blend agent, and a resin.

Abstract: A method for controlling binary thermal printers increases the effective output resolution of the thermal printer above the native resolution of a print head having a plurality of individual resistive heating elements arranged in a print line. An increase in the effective resolution of a binary output image is achieved by using an over-drive energy to control a relative position of a binary edge of a pixel image at a resolution that is less than the native resolution of the thermal printer. In a preferred embodiment, an under-drive energy may also be used with an adjacent over-drive energy to further control the relative position of the binary image of the pixel image. The over-drive energy is higher than a native pixel drive energy, but lower than a maximum drive energy. The native pixel drive energy produces a binary pixel image having a native area corresponding to the native resolution of the thermal printer.

Abstract: A high resolution thermal printer capable of printing both directly on a thermally responsive media and indirectly through a thermally responsive donor media is disclosed. The printer has a printing media guide mounted as an intermediate clamshell structure to accurately position the printing media immediately adjacent the print head and platen. The printing media guide includes a nip roller and guide bar independently suspended on a spring biased, pivot plate arrangement. The printing media is centered on the supply spool, and the printer includes a read/write circuit to communicate with a profiler chip centrally mounted in the printing media roll. The printer may also include a read/write circuit to communicate with a donor profiler chip centrally mounted in the donor media roll. A constant pressure brake with a friction belt is used directly against the printing media. A spring arm latch/channel block arrangement is used to secure the printing media supply spool.

Abstract: Pixels in a grayscale image are identified for coalescing based on a corresponding value in a threshold matrix. This threshold matrix value is then used to determine both the color and number of pixels to be coalesced at this location. Grayscale pixels are then coalesced based on pixels which will ultimately be the same color as the identified pixel. The coalesced grayscale image is then compared on a pixel-by-pixel basis to corresponding values in the threshold matrix to determine a halftone image.

Abstract: An ink supply line support system (100) for a continuous ink refill system (10) for an ink jet printer (90) having a print carriage (91) that traverses across a print bed (96) and is adapted to receive one or more disposable ink jet cartridges (12). The ink supply line support system (100) includes an elongate guide structure (102) having a first end (104) operably connected to the ink jet printer (90) at a fixed location (106) and a second end (108) operably connected to the print carriage (91). The second end (108) is movable relative to the first end (104) in a first orientation along the direction in which the print carriage (91) traverses across the ink jet printer (90), but is substantially rigid relative to the first end in a second orientation that is transverse to the first orientation. An attachment mechanism (110) is positioned along an exposed surface (111) of the guide structure (100) for detachably securing at least a portion of at least one ink supply line (16) to the guide structure (102).

Abstract: A continuous ink refill system for an ink jet printer that uses disposable ink jet cartridges having a first predetermined ink capacity includes an ink reservoir that is external to a print carriage on which the disposable ink jet cartridges are mounted. The ink reservoir contains a second predetermined ink capacity that continuously refills an ink container within the disposable ink jet cartridge by a passive pressure differential between the disposable ink jet cartridge and the ink reservoir. The disposable ink jet cartridge is removably mountable in the print carriage and is a self-contained unit having a print head and an ink supply container maintained at a sub-atmospheric pressure that supplies the first quantity of ink to the print head. The ink reservoir storing the second quantity of ink that replenishes the ink supply container is limited to some multiple of the first quantity of ink above which said print head does not reliably operate.

Abstract: An ink refill system is provided for an ink jet printer having a print carriage that traverses across a print medium and is adapted to receive one or more ink jet cartridges. The ink refill system includes a disposable ink jet cartridge removably mountable in the print carriage and constructed as a self-contained unit that includes a print head and an ink supply container that stores a first quantity of liquid ink at a given subatmospheric pressure hydrodynamic condition. An ink reservoir external to the print carriage stores a second quantity of ink for replenishing the first quantity of ink in the ink supply container. Flexible supply tubing couples the ink reservoir to the ink supply container to supply ink from the second quantity of ink to the first quantity of ink during operation of the ink jet printer as the print carriage traverses across the print medium.

Abstract: A non-gray scale anti-aliasing method for smoothing one or more edges of an image to be printed by a binary imaging printer. The image is generated by rasterizing an ideal outline of the image using a processor means for processing a plurality of raster lines to form a pixel representation of the image to be communicated to the binary imaging printer. An ideal fill area representing the area inside the ideal outline for the pixel currently being processed is determined for each pixel in the raster line and then compared to at least a first and second comparison value. Based upon the comparison, a determination is made as to whether the pixel currently being processed will be turned on or turned off. In one embodiment, the comparison is made by the use of a lookup table having a set of predetermined comparison values that contain estimated fill values used by an accumulator to determine whether to selectively modify the pixel.

Abstract: A line rasterization technique for a non-gray scale anti-aliasing method smoothes the edges of a single pixel width line image to be printed by a binary imaging printer. The line image is generated by rasterizing an ideal line image as a plurality of raster lines to form a pixel representation of the line image to be communicated to the binary imaging printer. For each vertical transition point created by the ideal line image crossing two adjacent raster lines, the present invention smooths the line image by selectively modifying the on and off states of one or more pixels in an adjacent raster line on either side of the vertical transition point. The pixel representation of the line image is then communicated to the printer such that the printer may print the smoothed line image.