Abstract: An ink jet printhead body includes one or more zones for cleaning, guiding and stabilizing a printhead wiper of an ink jet printer. The printhead body includes a receptacle providing a reservoir for ink, and the receptacle includes a wall having an outer surface. The wall includes a region at which location of one or more ink discharge nozzles is established. A plurality of ribs is located in each of the wiper cleaning zones, which in turn is located to be adjacent the wall region. The orientation of the ribs may be defined with reference to a first axis extending in the plane of the outer wall surface and intersecting the wall region in a first direction, and by a second axis, or axis of symmetry, extending in the plane of the outer wall surface and extending substantially parallel to an edge of the wall and through a central portion of the region to perpendicularly intersect the first axis.

Abstract: A networked system having a host computer and multiple printers with bi-directional communications capabilities is provided in which the setup (configuration) of one printer can be easily communicated to another printer, using NPAP messages. The host computer can be used by a Network Administrator to "read" the setup or configuration information inside each of the printers connected to the network that have the required NPAP bi-directional communications capability. This setup information, once communicated to the host computer, can be stored in a long-term memory, such as a hard disk drive, for future reference. The setup information can also be communicated to one or more printers connected to the network, and such printers can be configured by the setup information in which that information is used either as their initial setup information, or as a modified setup.

Abstract: Apparatus, system and method is provided in which a primary printer prepares print data for use by its resident print engine, or by an alternate printer. The primary printer includes subsystems for receiving original print data from a device, such as a computer or scanner, and for converting the original print data into a data format compatible with the alternate printer.

Abstract: The invention is directed to a method of transmitting data from a host computer to a printer. Image data is provided which represents at least a portion of a print image to be printed by the printer. Locations of aboslute zero values in the image data and locations of non-absolute zero values in the image data are defined. The locations of the absolute zero values and the locations of the non-absolute zero values are mutually exclusive from each other. Both host computer and the printer are instructed of the locations of the absolute zero values in the image data. Only the image data having non-absolute zero values is transmitted from the host to the printer.

Abstract: A laser printer is provided having an automatic printhead identification system for use in a family of laser printers that are compatible with more than one model of printhead. For example, a single laser printer model can be made so that two different printheads can be successfully used, so long as the printer system knows which laser printhead has actually been installed. To detect which printhead has been installed, the printer operating system provides a reference clock signal having a pre-determined frequency, which dictates the rotational speed of the motor. Once the motor has achieved a "lock" operational speed, the printer measures the scan rate of the faceted mirror by detecting the time interval between pulses of the "HSYNC" signal. The HSYNC signal is sent to a "divide-by-n counter" circuit which divides the pulse frequency of the HSYNC signal, thereby increasing the time interval (by a factor of "n") that must be sensed by the system to determine which printhead is in fact installed.

Abstract: An improved printer is provided that receives a print job from a host computer and divides the bitmap image of a page to be printed into a series of image blocks or tiles. Each image block containing non-null data will be stored in the printer's memory system, typically placed in a non-contiguous memory location with respect to other blocks. The null image data blocks will not be stored in the printer's memory system, but instead only their locations on the physical printed page will be stored in a "block list table." Each entry in the block list table contains the beginning address of the physical RAM area that contains one of the image data blocks, and also contains other variables or attributes concerning the particular image data block, such as whether or not this block is a regular non-null data block, or a "no-op" (or "NOP") block containing null data.

Abstract: A method of reducing EMI when printing an image with a printer having a laser includes determining edge pels located near an edge of the image, determining interior pels located within the image and not edge pels, forming edge pels by operating the laser at a first duty cycle and forming at least a portion of a plurality of interior pels by operating the laser at a second duty cycle longer than the first duty cycle. Another aspect is a method of reducing EMI in a printer when forming a latent image on a photoconductive member by gating a light source ON and OFF, including the steps of identifying a first region near an edge of an image to be formed, the first region being formed by gating the light source at a first frequency; and identifying an interior region of the image to be formed, the interior region being formed by gating the light source at a second frequency lower than the first frequency.

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.