Abstract: An independent hardware pixel counter counts bits of print data in regions of interest. The independent pixel counter can be an application specific integrated circuit (ASIC), and is separate from a control processor. The independent hardware pixel counter selectively monitors a data bus carrying image data to or from a memory. Once the pixels of the image data have been counted, the count data can be sent to the control processor in order to implement a print strategy. The pixel counter counts the print data at a point when image data is being sent to the memory, since at that point the image data is both uncompressed and in a raster format, and thus can be easily analyzed. Additionally, because the image data is stored in the memory until enough print data has accumulated for printing, the processor is provided with sufficient time to gather and use print information before the counted image data is printed.

Abstract: A series of enable trains are designed to provide a predetermined increment of heat to the heating element of a thermal ink jet printer printhead. The enable trains are stored in tabular form in memory according to printhead temperature. The printhead temperature is sensed during the printing cycle and read by the printhead controller. The controller selects a enable train from the table and applies it to the heating element. When subsequent cycles call for a change in the enable train, the current enable train is blended with the new enable train to provide an average increment of heat.

Abstract: A method and an apparatus for a medium indexing device, such as an ink jet printer, that includes utilizing greater torque generated by a motor at lower speed and lower torque available by the motor at higher speeds. Motion profiling during acceleration and deceleration is designed to better utilize available torque provided by the motor in order to quickly position the medium during start-stop operations and to reduce the maximum power or speed required of the motor during the indexing operations. The motor may include a stepper or servo motor, and may apply to medium indexing devices other than printers. In addition, a velocity discontinuity in motor speed is provided near the stop position to prevent the medium from overshooting the intended stop position.

Abstract: Printing systems and methods that reduce inter-color bleeding between dark and light colored inks without losing productivity of a color ink jet printer by distributing the printing of a total amount of black ink required in a single swath over multiple passes while each of the color inks required for the same swath is printed in a single pass. For example, the print method may print a single swath by printing portions of the slow dry black ink in three passes while printing each of the fast dry color inks in single passes.

Abstract: A method and an apparatus for a medium indexing device, such as an ink jet printer, that includes utilizing greater torque generated by a motor at lower speed and lower torque available by the motor at higher speeds. Motion profiling during acceleration and deceleration is designed to better utilize available torque provided by the motor in order to quickly position the medium during start-stop operations and to reduce the maximum power or speed required of the motor during the indexing operations. The motor may include a stepper or servo motor, and may apply to medium indexing devices other than printers. In addition, a velocity discontinuity in motor speed is provided near the stop position to prevent the medium from overshooting the intended stop position.

Abstract: The present system counteracts the distorting effect of a bi-directional print head by reducing the visual effect of a satellite drop displacement when the print head is traveling in a direction that increases the satellite displacement from a main drop. The system can also counteract the distorting effect of the bi-directional print head by increasing the visual effect of a satellite drop misplacement when the print head is traveling in a direction that decreases the satellite misplacement from the main drop. The satellite drop displacement can be adjusted by correcting a measured ink temperature, and thereby, an amount of pre-pulsing prior to ejection of the ink.

Abstract: A low-cost, high precision encoder system includes a codewheel and two encoder sensors mounted at opposite sides of the codewheel to form a dual sensor system having a corrected output that corrects for eccentricity in the mounting of the codewheel and the sensors. The encoder system has a correction circuit that provides a corrected output based on inputs received from the two encoder sensors, which can be single or multiple channel encoders. Methods for achieving the corrected output signal include measuring a time between a signal from the first encoder and a signal from the second encoder and halving this time. Methods for identifying a leading signal from the two sensors are also provided.

Abstract: A sheet transport system has an encoder roller in direct contact with the sheet media and driven by the sheet media to detect and compensate for any registration error particularly at lead and trail edges during transport of the sheet media as media enters and exits transport nips. The invention is well suited for use in controlling and monitoring paper movement in incremental advance and print systems, such as ink jet printers. A biasing member ensures that the sheet media and encoder roller are in intimate contact. Preferably, a material with a high coefficient of friction is provided on an outer periphery of the encoder roller to assist in mating of the roller with the sheet media.