Abstract: A method and apparatus for reducing intercolor bleed using pixel spot size control to improve print quality is provided. The method includes printing pixels having a first spot size in an image region having a boundary between a first color portion and a second color portion of the image by ejecting first sized ink drops from the printhead nozzles, and printing border pixels having spot sizes smaller than the first spot size in the image region by ejecting smaller ink drops from the printhead nozzles, wherein the smaller ink drops are smaller than the first sized ink drops. A printing system is provided having means for printing pixels in the region having the first spot size and means for printing border pixels having spot sizes smaller than the first spot size.

Abstract: A simultaneous push-pull method of, and apparatus for, removing air bubbles from a powerable ink jet printhead are provided. The printhead includes a printhead die containing liquid ink and heating elements within ink channels, and has a nozzle face and nozzles connected to the ink channels. The simultaneous push-pull method includes providing a printhead capping member including side walls, a bottom wall, a vacuuming path through the bottom wall, and a capping recess defined by the side walls and the bottom wall. The method then includes applying heat energy to the heating elements to reduce a viscosity of ink in the channels, activating a print mode of the printhead, firing the printhead while in the print mode to eject droplets of liquid ink in an ink ejecting direction through nozzles into the capping recess.

Abstract: A method and apparatus for removing or relocating relatively small air pockets from the reservoirs of ink jet printheads through the use of a decompression technique. In one embodiment, an ink jet cartridge, after being filled with ink, is subjected to a relatively high vacuum by being placed in an evacutable container which is connected to a high vacuum source. The container may hold several cartridges for concurrent processing. In another embodiment, an accessory kit may be used to provide the same decompression process while the cartridge is installed in the printer and located at its maintenance station. The accessory kit could be incorporated into the printer.

Abstract: A liquid recording apparatus ejects droplets of liquid onto a recording medium. The apparatus has multiple liquid emitters whose emissions are activated by multiple power pulses. The power pulses are controlled to maximize the number of emitters which can be simultaneously energized while keeping the instantaneous power usage within prescribed boundaries. The multiple emitters are organized into banks of emitters whose numbers are small enough that all emitters within a bank can receive a correct level of power simultaneously without exceeding capacity of a shared power source. A circuit interleaves the power pulses to the emitters so that no bank of emitters are receiving power at the same instant of time.

Abstract: An improved temperature compensation method is disclosed in which a temperature sensing thermistor is formed on a substrate whose temperature is to be series of fractional thermistors which are selectively shorted out during a manufacturing process to provide a compensation for manufacturing variabilities of the temperature coefficient of resistance of the thermistor.

Abstract: To print an image having a 600 dpi resolution along the horizontal axis with an ink jet printer that has a 300 dpi resolution, the method alternately examines the odd and even numbered pixel rows of the image. Odd-numbered rows are examined in a left-to-right manner while even-numbered rows are examined in a right-to-left manner. In odd-numbered rows the even numbered pixels are deleted. In the even-numbered rows, the even numbered pixels are deleted starting from the right-most pixel. After deleting the respective pixels, ink drops are fired from the ink jet printer at areas corresponding to the remaining ON pixels. This visibly reproduces the image at the 600 dpi resolution.

Abstract: To print an image having a 600 dpi resolution along the horizontal axis with an ink jet printer that has a 300 dpi resolution, the method raster scans selected pixels from a selected pixel pattern. The image receiving member is then advanced a selected distance. Remaining pixels from the selected pixel image pattern are then raster scanned onto the image receiving member to visibly reproduce the image at a defined resolution.

Abstract: The printing operation of an ink jet printer is controlled based on the density of the image to be printed. Using the density, a required drying time for each swath of printed matter is determined based on the image density. Also using the density, a maximum print frequency of firing the ink jets is determined. The density is determined by filtering stored print data by dividing the print data into blocks and determining a maximum number of ON pixels in a block. Such filtering enables clusters of ON pixels to be detected thus providing a more accurate determination of the density.

Abstract: An ink jet printer has a temperature sensor as a permanent part thereof to measure the temperature of printheads which are an integral part of a replaceable printhead cartridge assembly. The temperature sensor is a part of the maintenance station and senses the temperature of the printheads each time the printhead enters the maintenance station. In the preferred embodiment, the temperature sensor is spring-loaded and is located at a printhead spitting location between fixed wiper blades and the capping location in the maintenance station, so that temperature is sensed each time the printhead enters and leaves the maintenance station to eject nozzle cleaning droplets onto a collection surface at the spitting location to clean the printhead nozzle face by the wiper blades, or to cap the printhead nozzles. To facilitate good thermal contact, a recess is provided in the heat sink upon which the printhead resides for entry by the spring-loaded temperature sensor.

Abstract: The printing of an image by a thermal ink jet printer is controlled based on an internal temperature of the printer adjacent the printhead and the density of the printed image. Prior to printing, the temperature of the printhead is estimated, and the density of the image is determined from stored print data. Based on the temperature and density, either a single-pass 100% coverage print mode or a double-pass checkerboard print mode is selected. Also based on the temperature and density, the printhead droplet ejection rate is set. Such control provides a printed image with high quality and prevents misfiring of the ink jets when temperatures and density are high.

Abstract: An ink jet printer has a temperature sensor as a permanent part thereof. The temperature sensor is mounted on the translatable carriage of the printer. A replaceable printhead cartridge having a printhead bonded to a heat sink is installed on the translatable carriage. Once the printhead cartridge is installed on the translatable carriage, the temperature sensor is placed into intimate contact with printhead'heat sink, so that the temperature sensor moves with the printhead and provides continual temperature measurement.

Abstract: An apparatus and method compensates for a voltage drop of electrical pulse signals selectively applied to a plurality of heater elements on a printhead of an ink jet printing device. A number of heater elements to be pulsed at a given time is determined and a time duration of each of the pulse signals is selected based on information including the determined number of heater elements to be pulsed. In another aspect, the position on the printhead of the heater elements to be pulsed is determined and the time duration of the pulse signals is selected further based on the determined position. By varying the time duration of the pulse signals applied to the heater elements, a voltage drop across the heater elements due to the number of heater elements simultaneously pulsed and/or the position of the heater elements on the printhead is compensated for, maintaining reliable jetting performance while minimizing the voltage by which operating printing voltage needs to exceed the threshold printing voltage.

Abstract: The subject invention comprises a printer system for a serial printer having an optical sensor detection system for the alignment of images on a sheet of print media, the correction of misalignment as a result of inaccurate alignment of the print media and the determination of the orientation of print media in a printer.

Abstract: The subject invention is an optical sensor detection system for a serial printer useful for the determination of alignment and misalignment of images on a sheet of print media and the correction of misalignment. The present invention includes a photoelectric sensor mounted on the carriage of a serial type printer to locate various indicator markings.In operation the sensor detects the position of a midpoint indicator when the carriage travels from right to left, and then from left to right. The positional information is then compared with the assumed mid-carriage position of the print head based upon the time of travel, that is, the predicted position of the sensor assuming no flex in the support members of the print head and no stretch of the belt driving the print head.

Abstract: An optical detector senses the teeth on a wheel rotating with an unwinding roll of medium in a printer and provides a signal which is used to count the sensed teeth to measure the rotation of the roll. When a predetermined proportion of a rotation is completed, the measured length of medium movement along a path through the printer during the predetermined proportion of a rotation is used to sense the condition of the medium. The conditions which may be sensed include amount of medium, medium thickness and medium malfunction. The circumference may, for example, be calculated and compared with a low medium circumference for the preselected or calculated thickness of the medium to detect a low medium condition. Periodically, the present medium position may be compared with its position when the last tooth was detected to sense a medium malfunction, either a medium out condition or a medium break.