Abstract: An ink jet printing apparatus includes a printhead controller including a printhead driver circuit having a set of ink jet nozzle control outputs and a printhead select circuit having a plurality of printhead select outputs. A plurality of printheads are provided, wherein each printhead includes a plurality of ink jet nozzles, a plurality of individually controllable ink jet nozzle firing circuits, and a printhead enable circuit, wherein the printhead enable circuit is electrically coupled between the plurality of individually controllable ink jet nozzle firing circuits and the set of ink jet nozzle control outputs, and wherein the printhead enable circuit is electrically coupled to one of the plurality of printhead select outputs and enables the electrical conduction of the plurality of controllable ink jet nozzle firing circuits upon receipt of a printhead select signal from one of the printhead select outputs of the printhead select circuits.

Abstract: The invention is directed to a method of calibrating a laser in an electrophotographic image forming apparatus used for producing a print image on a print medium. A laser having a selectively energizable laser beam output is provided. A rotatable optical device and the laser combine to define a movable projection path of the laser beam output. Rotation of the optical device results in movement of the projection path across a scan line overlaying a photoconductive drum. The optical device has a rotational acceleration upon initial rotation thereof with a ramp-up period during which the rotational velocity increases. A safe area is established in a portion of the scan line which does not overlay an image area on the photoconductive drum. The laser is energized and calibrated when the projection path is positioned in the safe area. The calibration is carried out during the ramp-up period of the rotating optical device.

Abstract: An ink jet printhead includes a chip layer having a via for receiving ink, and having at least one actuator. A barrier layer is disposed adjacent the chip layer, and forms at least one throat which has a width and a cross-sectional area. The barrier layer also forms at least one bubble chamber, with each throat adapted to receive ink from the via and provide it to the respective bubble chamber. A nozzle layer is disposed adjacent the barrier layer, opposite the chip layer, and forms at least one nozzle for ejecting ink from the respective bubble chamber when the ink is energized by the associated actuator. At least one post is disposed proximate the throat, and extends part way between the chip layer and the nozzle layer. The post forms one or more gates through which the ink must pass from the via to the at least one throat.

Abstract: An improved networked system having a host computer and multiple printers is provided in which the printers have a bi-directional data communications capability and have at least one memory device capable of storing print data and other types of data files. The host computer can be utilized by a user or a Network Administrator to "read" the contents of each memory device on each printer connected to the network that has the NPAP bi-directional communications capability. The user/Network Administrator can de-fragment data files (e.g., print job files) on a flash RAM memory device, or can format one of the memory devices of a printer (which deletes all of the files stored on that memory device). Furthermore, the user/Network Administrator can transfer a file from the memory of one of the printers on the network to the memory of a second of the printers on the network.

Abstract: Nozzles in an ink jet printhead nozzle plate are laser formed into the nozzle plate at a spacing differing from that of the corresponding ink heating elements by a function of the thermal expansion characteristics whereby heating of the nozzle plate to activate a heat set adhesive for securing the nozzle plate to the heating element substrate expands the nozzle plate thereby aligning the nozzle axes with the corresponding heating elements.

Abstract: The invention is directed to a method of printing using an ink jet printer which jets a first color ink and a second color ink onto a print medium at locations defined by an image area having a plurality of pixels. The method inhibits intercolor bleeding between the first color ink and the second color ink. A first array of pixels in the image area is selected, with the first array being an M.times.N array wherein M and N are integers. A portion of the first array is defined as a second array of pixels, with the second array being an X.times.Y array wherein X and Y are integers. The integers X and Y are smaller than the integers M and N, respectively. The pixels within the second array are examined. The pixels within the first array are altered if the examined pixels within the second array substantially all correspond to the first color ink.

Abstract: A cartridge lockout system and method for an image forming apparatus, which includes a cartridge and a wheel rotatably mounted on the cartridge. The wheel has a plurality of digital indicators, each digital indicator being in a first condition or a second condition. A sensor is secured to the image forming apparatus adjacent the digital indicators for sensing the digital indicators and the first and second conditions of the digital indicators and producing a sensor signal during rotation of the wheel. Further included is an engine that has a machine class code and a cartridge support registry data table stored therein. The engine is in electrical communication with the sensor, receives the sensor signal, generates a cartridge class code based on the sensor signal, compares the cartridge class code to the machine class code, and disables operation of the engine if the cartridge class code does not match the machine class code in the cartridge support registry data table.

Abstract: An improved printer is provided that predicts how many pages can be printed before the toner or ink cartridge becomes empty, and also predicts how much time remains before this toner or ink cartridge becomes empty. This prediction is based upon the previous printing history of the printer while using this particular toner cartridge. After measuring the quantity of toner left in the toner cartridge, the printer of the present invention will display the approximate quantity of toner remaining in the cartridge on a screen of a host computer that is connected to the printer, either directly or through a network. The monitor screen of the host computer can also display the predicted number of pages remaining, based on the printer's previous usage history as described above.

Abstract: An ink jet print head identification system for providing print head identifying information to the electronics of an ink jet printer includes one or more programmable drain transistors integrated onto a print head chip. Existing address lines that interconnect the printer electronics and print head electronics are used to serially read the digital contents of each programmed transistor. The printer electronics reads each bit by combinationally applying a pull up voltage on two of the address lines while pulling down the voltage on one address line. If the drain of the transistor being read is programmed as an electrically conducting short, then the transistor will turn on and the voltage level on one of the pulled up address lines will not reach a logic high. If the drain is programmed as a non-conducting gap, the transistor will not conduct and the voltage level on both pulled up lines reach a logic high.

Abstract: Bidirectional communications between a host computer and a selected printer connected to the host, either locally or by way of a network, are used to provide a user of the host with access to a substantially real-time, visual and functional replica of the operator panel of the selected printer. A user at the host computer may also visually monitor the status of multiple printers at the same time from the same host display.

Abstract: A rasterizer described in relation to a printer apparatus for defining a page bit map, for a page to be printed, in blocks wherein there are multiple blocks across the width of the page and multiple blocks down the length of the page. A programmed microprocessor executes routines to render objects defined by received or processed drawing orders into blocks of the bit map and also to store drawing orders in display lists, each being associated with a block of the bit map. The blocks are rasterized, including rendering the display lists, on a row by row basis for serialization of the rows of blocks of the bit map to a print engine for printing.

Abstract: An improved printing system is provided having at least one host computer and a printer in which the printer acquires print job accounting information and communicates it to the host computer via NPAP messages. A host computer downloads print job data to the printer through a communications port on the printer (i.e., either a parallel port, serial port, or network port), and as the printer prints the print job that it received from the host computer, the printer temporarily stores job accounting information. At the end of the print job, the printer communicates that job accounting information back to armed host computers via a bi-directional communications port, including typical information such as: the job identifier number, job processing time, number of sheets of paper from each paper source, number of impressions from each paper source (either one-sided or two-sided impressions), the port identifier, the network user name, the name of the print job (as specified), and the printer's serial number.

Abstract: Bidirectional communications between a host computer and a printer connected to the host, either locally or by way of a network, are used to provide a user of the host with access to a substantially real-time, visual and functional replica of the operator panel of the printer. The user may view the replica to access all data available through the printer operator panel. Using a mouse or other input device, the user of the host computer can also effectively actuate any pushbuttons or other operator panel control devices depicted as part of the replica.

Abstract: A printer having a disposable print head which contains a consumable ink supply includes the capability of determining the level of ink in the print head without directly measuring the ink supply. The print head includes a number of resistors which can be driven to an open circuit condition by the printer. The printer includes a counter and memory for tracking the usage of the print head and a driver for selectively driving the print head resistors to an open circuit condition based upon such usage. The printer is also capable of detecting the condition of the resistors on the print head and producing a resultant visual display.

Abstract: A serial drop-on-demand ink jet printer having an ink cartridge mounted for reciprocation on a carrier which traverses paper advancing through the printer. The cartridge includes a nozzle array for the ejection of ink droplets onto the paper, and the carrier includes a tab upstream from the nozzle array, in the direction of paper travel, which touches the top surface of the paper and sets the printhead-to-paper gap. The paper is pushed against the tab and maintains a minimum gap to prevent paper from coming into contact with the nozzle array. The paper is urged against the tab into the proper position relative to the nozzle array by a deflectable guide which acts on the back surface of the paper.

Abstract: A computer and printer system in which communication between the computer and printer can be carried out in either a bidirectional mode or a unidirectional mode. As disclosed, the computer operates in a single-threaded multi-tasking environment in which a printer control utility application runs to facilitate bidirectional communication with an attached printer. The application program maintains the computer parallel port in a bidirectional communication and printing mode, but is capable of taking the parallel port out of this mode in order to perform unidirectional printing, either from another application operating in the multi-tasking environment or from a DOS session running in the environment. The printer control utility prevents the mixing of unidirectional and bidirectional print jobs through the parallel port.

Abstract: A maintenance station for maintaining either a monochrome or a multi-color printhead in an ink-jet printer includes a single flexible wiper having a first wiping edge for wiping the ink-jet nozzle surface of a monochrome printhead and a plurality of second wiping edges for wiping the ink-jet nozzle surface of a multi-color printhead. Wiping of a monochrome printhead is accomplished by moving the printhead to one side of the wiper, raising the wiper into the path of travel of the nozzle surface, and moving the printhead past the wiper. Wiping of a multi-color printhead is accomplished in a similar manner but the printhead is first positioned on the opposite side of the wiper. The flexibility of the wiper is chosen to apply an optimum wiping force to a multi-color printhead as the printhead is moved past the wiper. A backstop is provided at one side of the wiper to brace it against deflection, so that the wiper applies a greater wiping force to a monochrome printhead than it does to a multi-color printhead.

Abstract: An ink-jet printer cartridge having a center reservoir chamber and two side reservoir chambers for holding inks of three different colors is provided with ink flow pathways of special configuration for connecting the reservoir chambers to exit ports at the print element. The ink flow pathways are provided with ridges extending along substantially their entire lengths so that air bubbles cannot completely block ink flow through the pathways. The ink flow pathways are disposed such that they have a vertical component of direction over their entire length and the pathways connecting the side reservoir chambers to exit ports include duct portions disposed at compound angles relative to the axes of the cartridge so that air bubbles, because of their buoyancy, will naturally tend to drift upwardly through the inclined ducts toward the reservoir chambers during normal usage, or drift toward the exit openings when the cartridge is inverted for priming.