Abstract: An electrophotographic image forming apparatus includes a photoconductive drum and a transfer roll-positioned adjacent to and defining a nip with the drum. An image substrate travels through the nip in an advance direction. A toner cartridge assembly is positioned in association with the drum and above the image substrate. A pre-transfer erase assembly having a light emitting outlet is positioned between the toner cartridge assembly and the image substrate. The light emitting outlet is directed toward the drum.

Abstract: An oil web system and method for operating a fuser system of an imaging apparatus in which remaining life of the oil web is determined from data on drive mechanism activation and data on web advancement lengths. A warning signal can be issued upon a predetermined remaining length being reached, and the machine can be disabled upon exhaustion of the web life.

Abstract: A method of minimizing error in an estimate of a position of a sheet of print medium in an electrophotographic machine includes providing a transport system including a gearing system to drive a roll for moving the sheet of print medium along a print medium path. The gears are in constant mesh with each other and with an actuator. The electrophotographic machine is provided with a toner transfer point at which the toner can be transferred to the moving sheet of print medium. A sensor is placed at a set distance away from the transfer nip along the print medium path. This distance is approximately equal to an integer multiple of the resulting distance traveled by the medium during one revolution of the lowest frequency component of the transport system. The frequencies associated with all other components in the transport system, including the actuator and an encoder wheel, are designed to be an integer multiple of this lowest frequency.

Abstract: An ink jet printer receives image data defining a pattern of dots in a non-square rectangular grid and prints the pattern of dots on a print medium based on the image data. The pattern of dots consists of at least four interlaced checkerboard arrays of dots printed in four passes of the print head across the print medium, where each one of the four checkerboard arrays is printed during a different one of the four passes. Each of the checkerboard arrays is offset from the other checkerboard arrays by a predetermined spacing in at least one of the first and second directions. The printer prints the second checkerboard array horizontally offset from the first checkerboard array by a distance substantially equivalent to {fraction (5d/4)}, where d is the diameter of the printed dots.

Abstract: An apparatus and method are provided for preventing unraveling of an oil supply web by the selective application of a locking mechanism to a web supply roller when a fuser hot roller or other fuser drive roller is forced to rotate in a reverse rotation. The locking mechanism is released when the fuser hot roller resumes normal rotation. A pivoting arm is adapted for pivotal movement into locking engagement with the web supply roller. A braking element, such as a ratchet latch, attached to the end of the pivoting arm, or pawl, contacts a rotary follower or other rotational member connected to and operable to prevent rotation of the web supply roller. The braking element is disengaged when the fuser hot roller resumes rotation in the normal direction, as the pawl is pivoted out of engagement with the rotary follower.

Abstract: A sensor and method for detecting the presence of a protective tape on a printer cartridge in contact with a printer cartridge interface, preferably a printer carrier cable, in a printer. The sensor includes at least a first contact and a second contact between the printer cartridge and printer carrier cable, and a protective tape on the printer cartridge. The protective tape bridges an electrical connection between the first contact and second contact when the printer cartridge is in contact with the printer carrier cable. The first and second contact are either both on the printer cartridge or on the printer cartridge interface, or one contact is one the printer cartridge while the other is on the printer cartridge interface. The protective tape is an electrically-conductive material, or alternately is non-conductive and can include either a metal strip or a conductive adhesive that bridges an electrical connection between the first contact and second contact.

Abstract: A filter tower structure for removing air or gas bubbles from an ink jet printing structure which includes a filter tower attached to an ink reservoir for feeding ink from the reservoir to a printhead, the filter tower structure including a conduit having an interior in flow communication with the ink reservoir and the printhead and a tube having a first end in flow communication with the interior of the conduit and a second end in flow communication with a vacuum source, wherein activation of the vacuum source results in the application of a reduced pressure to the interior of the conduit such that air or gas bubbles are caused to flow into the tube and exit the conduit and ink from the reservoir is caused to flow into the conduit.

Abstract: An ink jet printing apparatus is provided comprising first and second print cartridges. The first print cartridge includes at least one first resistive heating element in at least one first ink-containing chamber having a first orifice. The first heating element has a first surface area. The second print cartridge includes at least one second resistive heating element in at least one second ink-containing chamber having a second orifice. The second heating element has a second surface area which is less than the first surface area. The apparatus further comprises a driver circuit, electrically coupled to the first and second print cartridges, for selectively applying to one of the first and second heating elements via a common drive circuit a firing pulse. The firing pulse to the first heating element causing a vapor bubble to be produced in the first chamber such that a droplet of ink of a first size is ejected from the first chamber orifice.

Abstract: A method and apparatus provides for minimizing visual artifacts resulting from laser scan process direction position errors in an electrophotographic machine. The electrophotographic machine has defined therein a process direction, and includes a photoconductive device having an image forming surface. A printhead unit is provided for generating a laser beam, wherein the printhead unit includes optics for scanning the laser beam to form a plurality of scan lines extending across the photoconductive device in a scan direction which traverses the process direction. Adjacent scan lines of the plurality of scan lines are separated by a scan line separation distance. A controller is electrically coupled to the printhead unit for controlling the power of the laser beam during the scanning of an adjacent pair of scan lines to form a synthesized dot which lies at a synthesized position between the adjacent pair of scan lines.

Abstract: A method and apparatus for reducing the amount of air entrained in ink of ink jet printer cartridges especially during filling of the ink cartridge is disclosed. The method includes providing ink suitable for ink jet printing heating the ink to a predetermined temperature range to liberate air entrained in the ink, and then filling the ink jet cartridge while maintaining the elevated temperature of the ink. The apparatus includes an ink holding tank in fluid communication via a conduit with an air removal device that includes a heater adapted to elevate the temperature of the ink and liberate air entrained therein. The air removal device is in turn in fluid communication via a second conduit with an ink cartridge. Preferably, the heater is a temperature controlled resistance heater while the air removal device further includes a baffled holding chamber adapted to allow the ink time to reach and maintain the elevated temperature.

Abstract: A method for making a nozzle plate for an inkjet printer by laser ablating a nozzle plate material. The method includes the steps of a) determining a plurality of desired nozzle hole locations, b) ablating the area of the nozzle plate material surrounding the desired locations of the holes to a predetermined depth to provide a plurality of flow paths c) ablating a nozzle through the full thickness of the nozzle plate material at each desired nozzle hole location, wherein unablated material surrounds each nozzle hole to provide a chamber, and d) ablating a throat region through a portion of the unablated material surrounding each nozzle hole so that each chamber is in flow communication with at least one flow path outside of the chamber.

Abstract: A color ink jet printing device has an off-board ink reservoir for each color being printed. Each reservoir comprises at least two separately replaceable cartridges from which ink is supplied under positive pressure to refill replaceable printhead cartridges. A visual indicator is provided for each off-board cartridge to indicate when the cartridge is empty and this indicator is turned on if the ink supply in the cartridge is exhausted during a refill operation. Printing is not stopped until all off-board cartridges holding one color of ink are empty. At this time the empty cartridges that held any color ink, are replaced. After each operator intervention to replace empty cartridges, the volume of each color ink will be (N−1)/N of maximum reservoir capacity where N is an integer greater than one and represents the number of cartridges in the reservoir.

Abstract: A method of reversing a laser beam in a machine includes orienting a pair of reflective surfaces at an angle of approximately 90° relative to each other. The laser beam is directed in a first direction such that the laser beam sequentially impinges upon a first of the reflective surfaces reflects off of the first reflective surface, impinges upon a second of the reflective surfaces, and reflects off of the second reflective surface in a second direction substantially parallel to and opposite the first direction. A pivot axis is substantially parallel to each of the reflective surfaces. Each of the reflective surfaces is pivoted about the pivot axis by a substantially equal angle to thereby change a position of the laser beam after reflecting off of the second reflective surface.

Abstract: The invention relates to a molded cartridge body including a substantially one-piece molded polymeric structure defining two or more ink cartridge positions and being removably mountable on a printer carriage. The molded cartridge body has a front panel member opposite a back panel member, side panel members connected to the front and back panel members and a bottom panel member having an ink cartridge side and a printhead side which is connected to a lower edge of each of the front, back and side panel members, the front, back, side and bottom panel members defining an open-ended cavity. The open-ended cavity contains an ink chamber for each of the ink cartridges, each of the ink chambers being in flow communication with a printhead attached to a printhead location on the cartridge body. A needle panel member containing an ink needle for each of the ink chambers is provided, the panel member being attached to the ink chambers so as to define closed ink chambers.

Abstract: A method and apparatus for correcting transfer belt positioning error in printers. A transfer belt subassembly includes a transfer belt, a plurality of rollers, and a storage device. The transfer belt also includes a home position indicator. The subassembly is measured and characterized before being installed in a printer. The measurement and calibration data for the transfer belt is stored in the storage device. When the transfer belt assembly is inserted into a printer, a controller within the printer is placed in communication with the storage device. A sensor is used to determine the home position of the belt from the indicator, and a resulting signal indicating the belt is at the home position is provided to the controller. The controller utilizes the measurement and calibration data from the storage device to control the motor to correct for belt positioning errors.

Abstract: An ink jet print cartridge is provided for use in an ink jet printer. The cartridge comprises a printhead including a heater chip. The printhead is adapted to generate ink droplets in response to the heater chip receiving energy pulses from a printer energy supply circuit. A peltier effect cooling cell is associated with the heater chip for cooling the heater chip. The cooling cell receives current from the printer energy supply circuit as a function of energy flow to the heater chip.

Abstract: The invention relates to an improved ink jet pen for an ink jet printer. The pen includes a pen body having raised end walls, a recessed substantially planar portion between the end walls containing two or more printheads and flexible circuits therefor, the flexible circuits being attached to the pen body in the recessed portion between the raised end walls. A polymeric material is disposed between adjacent flexible circuits in the recessed portion having a height sufficient to protect a wiper from damage from exposed edges of the flexible circuits between adjacent printheads during a printhead cleaning operation. The improved pen lends itself to simplified manufacturing processes yet provides enhanced mechanical protection of the wiper and critical electrical structures and enhanced corrosion resistance from ink.