Low resolution grey level printing method from high resolution binary input file
AssigneeEastman Kodak Company
InventorYee S. Ng
Life of this patent
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Abstract
An electronic printing apparatus and method transforms a high resolution binary data file to a lower resolution grey level file for printing by a lower resolution printer. Recording is made upon an electrophotographic recording medium preferably employing discharged area development. In order to preserve sharpness to the printed image and reduce edge jaggedness in the recorded image, exposures for grey level pixels are skewed towards the longer durations. In addition, pixel locations in the original binary data file are used to determine the need for pixel shifting during recording of the printed grey level pixels.
Claims34
A method of printing a high quality image using a printer that includes a printhead of a low resolution, said method comprising the steps of:
- inputting a high resolution binary data image file of said image represented in binary data form that is of higher resolution in one scan direction than said low resolution;
- sequentially operating on blocks of data from said binary data file to define multibit grey level pixel data of said low resolution for recording by said printer;
- and
- printing said pixel data to form the image by operating the printhead to record grey level pixels on a recording medium at said low resolution.
A method of non-impact printing with high quality using a printhead of relatively low resolution, said method comprising the steps of:
- inputting as an address into a memory a multibit digital data signal representing a grey level of a pixel to be recorded and a second signal indicating classification of the pixel as either a text pixel or not a text pixel;
- outputting from said memory a third signal representing an exposure parameter wherein the exposure parameter differs in accordance with said classification;
- and
- using said third signal to control said printhead for recording said pixel.
A method of non-impact printing comprising the steps of:
- generating signals representing a binary data file of a first resolution;
- sequentially operating on blocks of data from said binary data file to generate a grey level data file of a second resolution that is lower than said first resolution;
- inputting into a memory a multibit digital data signal representing a grey level of a pixel to be recorded and a second signal representing locations of data bits in one of said blocks of data;
- outputting from said memory a third signal representing an exposure parameter wherein the exposure parameter differs in accordance with said second signal;
- and
- using said third signal to control a printhead for recording said pixel.
An apparatus for printing high quality text with a low resolution printhead, said apparatus comprising:
- means for inputting a high resolution binary data text file of said text represented in binary data form in a first resolution;
- means for sequentially operating on blocks of data from said binary data file to define multibit grey level pixel data of lower resolution than said first resolution;
- and
- printing means for printing said pixel data to form the text by recording grey level pixels on a recording medium at the lower resolution.
A method of printing high quality text using a printer that includes a printhead of a low resolution, said method comprising the steps of:
- (a) sequentially operating on blocks of data from a data text file of a high resolution and calculating multibit grey level pixel data of said low resolution for recording by said printer;
- and
- (b) printing said pixel data to form the text by operating the printhead to record grey level pixels on a recording medium at said low resolution.
Dependencies are inferred from the claim text.