Method and apparatus for correcting printhead, printhead corrected by this apparatus, and printing apparatus using this printhead
First Claim
1. An apparatus for correcting a printing characteristic of a printhead having a plurality of printing elements and memory means for storing data, comprising:
- printhead drive means for driving the printhead to perform experimental printing on a recording medium;
detecting means for detecting a variation in density per a predetermined area of an image that has been printed on the recording medium, wherein the predetermined area is defined by N pixels in a first direction in which the plurality of printing elements are arrayed and M pixels in a second direction different from the first direction;
correction-data generating means for generating, per the plurality of printing elements, correction data for correcting the variation in density detected by said detecting means; and
writing means for writing the correction data in said memory means of the printhead,wherein N is a positive integer greater than 1 and less than 9,M is a positive integer greater than 15 and less than 1025,dots are formed in the predetermined area by sampling pixels, anda resolution per N pixels is less than 300 dpi.
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Accused Products
Abstract
A method and apparatus for correcting a full-line printing head, which has a high printing quality, at a high yield, as well as a printhead corrected by this apparatus and a printer using this printhead. In the final stage of a semiconductor manufacturing process, the manufactured printhead is made to perform an experimental printing operation to print a predetermined dot pattern. The dot pattern is imaged by a CCD camera and image processing is executed to obtain an image signal. A plurality of pixels (4×32 dots) from among the pixels represented by the image signal are gathered together, the white or black pixels among these are counted and binarization is performed by comparing the count with a predetermined threshold value. Correction data for adjusting the amount of ink discharged from each nozzle of the printhead is generated based upon the binarized data, and the correction data is written in a memory provided in the printhead.
116 Citations
30 Claims
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1. An apparatus for correcting a printing characteristic of a printhead having a plurality of printing elements and memory means for storing data, comprising:
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printhead drive means for driving the printhead to perform experimental printing on a recording medium; detecting means for detecting a variation in density per a predetermined area of an image that has been printed on the recording medium, wherein the predetermined area is defined by N pixels in a first direction in which the plurality of printing elements are arrayed and M pixels in a second direction different from the first direction; correction-data generating means for generating, per the plurality of printing elements, correction data for correcting the variation in density detected by said detecting means; and writing means for writing the correction data in said memory means of the printhead, wherein N is a positive integer greater than 1 and less than 9, M is a positive integer greater than 15 and less than 1025, dots are formed in the predetermined area by sampling pixels, and a resolution per N pixels is less than 300 dpi. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A printhead corrected by a method of correcting a printing characteristic of said printhead, said printhead having a plurality of printing elements and a memory unit for storing data, said method comprising:
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a testing step of performing experimental printing on a recording medium using the printhead; a detecting step of detecting a variation in density per a predetermined area of an image that has been printed on the recording medium, wherein the predetermined area is defined by N pixels in a first direction in which the plurality of printing elements are arrayed and M pixels in a second direction different from the first direction; a correction-data generating step of generating, per the plurality of printing elements, correction data for correcting the variation in density detected in said detecting step; and a writing step of writing the correction data in the memory unit of the printhead, wherein N is a positive integer greater than 1 and less than 9, M is a positive integer greater than 15 and less than 1025, dots are formed in the predetermined area by sampling pixels, and a resolution per N pixels is less than 300 dpi. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A printing apparatus using a printhead corrected by a method of correcting a printing characteristic of said printhead, said printhead having a plurality of printing elements and a memory unit for storing data, said method comprising a testing step of performing experimental printing on a recording medium using the printhead, a detecting step of detecting a variation in density per a predetermined area of an image that has been printed on the recording medium, wherein the predetermined area is defined by N pixels in a first direction in which the plurality of printing elements are arrayed and M pixels in a second direction different from the first direction, a correction-data generating step of generating, per the plurality of printing elements, correction data for correcting the variation in density detected in said detecting step, and a writing step of writing the correction data in the memory unit of the printhead, said apparatus comprising:
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receiving means for receiving the correction data from the printhead; generating means which, on the basis of the correction data, generates a control signal for controlling operation of drive means in such a manner that the plurality of printing elements form uniform pixels; and transmitting means for transmitting the control signal to the printhead, wherein N is a positive integer greater than 1 and less than 9, M is a positive integer greater than 15 and less than 1025, dots are formed in the predetermined area by sampling pixels, and a resolution per N pixels is less than 300 dpi. - View Dependent Claims (19, 20, 21, 22)
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23. A method of correcting a printing characteristic of a printhead having a plurality of printing elements and a memory unit for storing data, said method comprising:
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a testing step of performing experimental printing on a recording medium using the printhead; a detecting step of detecting a variation in density per a predetermined area of an image that has been printed on the recording medium, wherein the predetermined area is defined by N pixels in a first direction in which the plurality of printing elements are arrayed and M pixels in a second direction different from the first direction; a correction-data generating step of generating, per the plurality of printing elements, correction data for correcting the variation in density detected in said detecting step; and a writing step of writing the correction data in the memory unit of the printhead, wherein N is a positive integer greater than 1 and less than 9, M is a positive integer greater than 15 and less than 1025, dots are formed in the predetermined area by sampling pixels, and a resolution per N pixels is less than 300 dpi. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30)
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Specification