International Business Machines Corporation

Infoprintsolutions Company, LLC

Ricoh Production Print Solutions LLC

John Charles Wilson

Larry Mason Ernst

Mikel J Stanich

Samuel Neely Hopper

Gerald L Smith

Christopher Starbuck Kush

Louis A Bustamante

Michael Jeffrey Holley

William Ashmead Courtenay Bateman, Iii

George G Promis, Jr

Michael G Munson

Methods and systems herein provide for print data compensation for a print head based on a lateral offset of a media relative to the print head. In one embodiment, a print controller of a printer identifies an edge of a media that is parallel to a direction of travel of the media, and determines a lateral offset between the edge of the media and a print head of the printer. The print controller then modifies data for the print head based on the lateral offset to compensate for a lateral motion of the media relative to the print head.

Print data compensation for variations in paper position within a printing system

A mechanism for integrating print quality enhancement (PQE) and multi-bit halftone data is disclosed. A system of embodiments of the invention includes a print control unit communicably coupled to a printer, the print control unit operable to process received multi-bit input print data for printing by the printer. The system further comprises a PQE card communicably coupled with the printer, the PQE card configured to separate multi-bit text and line art input data from multi-bit halftone image input data in the multi-bit input print data, ignore any of the identified multi-bit halftone image input data for purposes of applying PQE technology to the identified multi-bit halftone image input data, and apply the PQE technology to the identified multi-bit text and line art input data. Lastly, the system includes a print head communicably coupled to the printer, the print head operable to print multi-bit output created by the PQE card.

Mechanism for integration of print quality enhancement (PQE) and multi-bit halftone data

An apparatus for providing delay signals to perform print scan line synchronizations within a laser printer is disclosed. The apparatus includes a voltage-control oscillator, a frequency divider and multiple output control modules. The voltage-control oscillator converts a clock signal to a higher frequency signal. The frequency divider then reduces the frequency of the higher frequency signal. Then, each of the output control modules generates a delay signal, and each of the delay signals is delayed by no more than one tenth of a clock cycle from an adjacent one of the delay signals.

Apparatus for providing delay signals to perform print scan line synchronization within a laser printer

Disclosed is a method, system and program product for performing multiple-pel print quality enhancement (PQE). As in known methods of PQE, a determination is made of an adjusted sub-pulse value of each pel of an image. In accordance with embodiments of the present invention, at least two adjacent pels are then grouped together and a determination is made of a combined pulse width value to charge the combined area of the at least two adjacent pels. Also determined is position information indicating the alignment of the pulse width within the combined area. The combined pulse width and position information is sent as input to a pulse width modulator operating at a speed equal to the video data rate of the printer divided by the number of pels for which the pulse width data is combined.

Method, system and program product for multiple pel print quality enhancement

Disclosed is a method, system and program product for performing multiple-pel print quality enhancement (PQE) using amplitude modulation. A determination is made of an adjusted peak amplitudes value of each pel of an image. At least two adjacent pels are then grouped together and a determination is made of a peak amplitudes value that will serve as a gray amplitude value for each pel in the pel group. Also determined is position information indicating the alignment of the peak amplitudes within the combined area. The combined peak amplitudes and position information is sent as input to an amplitude modulator operating at a speed equal to the video data rate of the printer divided by the number of pels for which the peak amplitudes data is combined.

Method, system and program product for amplitude modulated multiple pel print quality enhancement

Errors in regard to toner materials which may or may not correspond to toner materials installed in a developer unit of a print engine are avoided by providing storage of data concerning the toner in the printer rather than the dedicated processor. A feedback link is thus developed which extends from the developer unit or print engine through the dedicated processor to the supporting processors. Confidence levels in the correspondence of the information and the installed toner are increased by use of a simple switch position associated with the location of a developer unit. The feedback arrangement for avoidance of printing errors is also fully compatible with a customer changeable developer feature while allowing the printer to be operated in accordance with operating parameters specific to a special purpose toner such as MICR or a color toner.

Closed loop feedback system for alternative toners

A duplex printing system including two print engines arranged in tandem for printing a first and second density patch on a print medium, at least one density sensing device adapted for measuring the density of the first and second density patches printed on the print medium by the two print engines and a control for controlling the adjustment of the print engines to enable the density and dot gain of the print output of the first and the second print engines to match. The printing system of the present invention is further characterized by the measurement of the density of the density patch printed by each print engine after the print medium has advanced through the printing system. Thus, the print medium and first and second density patches printed by each print engine is subjected to the same conditions and influences as a print job processed by the printing system. Accordingly, density measurements and adjustments made to the print engines to vary the density of the print engine outputs will be realized in a print job subsequently produced by the printing system and the resultant print job will include printed images printed by two print engines that have matching print characteristics, namely matching density and dot gain.

Matching the printing characteristics between two engines of a duplex print system

An method and apparatus for error checking. A known test pattern is written into a predetermined byte of a scan line. The method may include generating a known test pattern in a byte of a scan line and transmitting the scan line data through a first data path. The scan line data at the end of the first data path may be evaluated to determine if the test pattern is still in the predetermined byte of the scan line. If the pattern in the predetermined byte is correct, the test pattern may be removed from the predetermined byte and the scan line data may be transmitted to a print engine. If the pattern in the predetermined byte is incorrect, then a signal may be sent to terminate the transmission of the scan line data.

End to end walking print

A motor driving system which is particularly useful for driving scanning carriages in a continuously variable reducing electrophotographic copier. The motor driving system produces one of a number of different controlled and repeatable position acceleration and velocity profiles of the scanning carriage with respect to motion of the copier drum; a different position acceleration and velocity profile is produced for each reduction mode in a substantially continuous range of reduction modes. The motor driving arrangement includes a single control loop for driving a servo motor which provides the drive for the scanning carriage. A driving signal source produces a driving signal pulse train, each pulse representing a desired increment of motor travel, and a direction signal representative of the desired direction of travekl. A tachometer is responsive to servo motor motion and produces an output signal representative of the direction of motion; the output signal includes a series of tachometer pulses, each pulse representing a given increment of servo motor movement. A logic circuit couples the output of the tachometer, the driving signal pulse train and the direction signal to an up/down counter which is stepped in one direction for each driving signal pulse, and which is also stepped in another or one direction, respectively, for each tachometer pulse which represents a direction which is the same as or different from the direction of the direction signal. The output of the up/down counter, converted to analog form, provides an input signal to drive the servo motor. In order to control the acceleration, velocity and position profiles of the scanning carriage, the driving signal source produces a train of output pulses whose repetition rate is precisely controlled in relation to the motion of the drum. The driving signal source includes a counter which produces a pulse output each time a predetermined count is reached, the counter is stepped at a rate related to the velocity of the drum, and the repetition rate of the output pulses is controlled by providing a sequence of quantities, from a storage matrix, to alter the modulus of the counter in a predetermined pattern.

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Longmont, CO, United States of America

John Charles Wilson