# US 2010/0165367 A1 · Printer Gradation Correction Method and Color Patch Image > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0165367 A1 - Document ID: US20100165367A1 - Status: Published application - Kind: A1 - Application number: 12/638,899 - Filed: 2009-12-15 - Published: 2010-07-01 - Earliest claimed: 2008-12-26 - Assignees: Konica Minolta Business Technologies, Inc. - Inventors: Shoichi Nomura - Web page: https://patentgrep.com/patent/US20100165367A1 ## CPC - H04N 1/6033: {using test pattern analysis (H04N1/6055 takes precedence)} - G03G 15/0131: {for transferring a pattern to a second base} - G03G 15/5058: {using a test patch} - G03G 15/5062: {by measuring the characteristics of an image on the copy material} - H04N 1/4078: {using gradational references, e.g. grey-scale test pattern analysis} - G03G 2215/00059: on intermediate image carrying member, e.g. transfer belt - G03G 2215/00063: Colour - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract A printer gradation correcting method, comprises the steps of: outputting a color patch image by a printer based on image data of a color patch image; measuring a gradation of the outputted color patch image by a color measuring device so as to obtain a gradation measurement value; and correcting a gradation characteristic of the printer based on the gradation measurement value. The color patch image includes a patch-shaped image having a uniform gradation of a predetermined gradation representative value and gradation fluctuation of a predetermined color component added in the patch-shaped image, and the added gradation fluctuation is structured such that a total of gradation fluctuation measured in a measurement region by the color measuring device becomes a predetermined value. The gradation characteristic of the printer is corrected based on the gradation representative value, the predetermined value of the total of gradation fluctuation, and the gradation measurement value. ## Claims ### Claim 1 A printer gradation correcting method, comprising the steps of: outputting a color patch image by a printer based on image data of a color patch image; measuring a gradation of the outputted color patch image by a color measuring device so as to obtain a gradation measurement value; and correcting a gradation characteristic of the printer based on the gradation measurement value; wherein the color patch image includes a patch-shaped image having a uniform gradation of a predetermined gradation representative value and gradation fluctuation of a predetermined color component added in the patch-shaped image, and the added gradation fluctuation is structured such that a total of gradation fluctuation measured in a measurement region by the color measuring device becomes a predetermined value, and wherein the gradation characteristic of the printer is corrected based on the gradation representative value, the predetermined value of the total of gradation fluctuation, and the gradation measurement value. ### Claim 2 (depends on 1) The printer gradation correcting method described in claim 1, wherein the gradation fluctuation is a stripe pattern in which a cycle of the stripe pattern is determined in accordance with a shape of the measurement region. ### Claim 3 (depends on 1) The printer gradation correcting method described in claim 1, wherein the color patch image is structured so as to be printed together with plural color patch images on a color chart on which a guide mark to determine a position of a measuring region is provided, and the color measuring device is adapted to measure a measurement region determined based on the guide mark and obtains a gradation measurement value on the color patch image. ### Claim 4 (depends on 1) The printer gradation correcting method described in claim 1, wherein the color patch image is structured so as to be printed together with plural color patch images on a color chart, and the amplitude of gradation fluctuation to be added into the color patch image is one third or more of a gradation difference between the color patch image and a neighboring color patch image of the color patch image. ### Claim 5 (depends on 1) The printer gradation correcting method described in claim 1, wherein the gradation fluctuation is a stripe or a lattice pattern and an orientation of gradation fluctuation is set in accordance with characteristics of the printer. ### Claim 6 (depends on 1) The printer gradation correcting method described in claim 1, wherein a gradation pattern image is outputted by the printer based on gradation pattern image data added with gradation fluctuation of a predetermined color component, the outputted gradation pattern image is measured by the color measuring device so as to obtain an amplitude of gradation fluctuation for each gradation value, and a gradation value to cause a tone jump of the predetermined color component is determined based on the size of the amplitude of each gradation value. ### Claim 7 (depends on 6) The printer gradation correcting method described in claim 6, wherein the amplitude of gradation fluctuation is made larger relatively in the vicinity of a gradation value predicted to cause a tone jump in the gradation characteristic of the printer. ### Claim 8 (depends on 6) The printer gradation correcting method described in claim 6, wherein when there is a region including discontinuous points in a different portion image between a standard image of a gradation chart image and the outputted gradation chart image or in a differential image of the outputted gradation chart image, the region is not made as the measurement region by the measuring device. ### Claim 9 (depends on 1) The printer gradation correcting method described in claim 1, wherein two kinds of color patch images having the same gradation representative value and different respective amplitudes of gradation fluctuations are outputted by the printer, and whether or not the number of kinds of color patch images is to be increased is determined in accordance with a difference in measurement values between the outputted two kinds of color patch images. ### Claim 10 (depends on 6) The printer gradation correcting method described in claim 6, wherein a gradation region in which a tone jump appears is recognized based on the measurement results, and image data in the gradation region is applied with additional processing after the correction of gradation. ### Claim 11 (depends on 10) The printer gradation correcting method described in claim 10, wherein the additional processing includes at least one of a change of a pseudo multi gradation processing method and random number addition processing. ### Claim 12 (depends on 1) The printer gradation correcting method described in claim 1, wherein amplitude of gradation fluctuation is set in accordance with a visual characteristic for a gradation region where the gradation fluctuation exists. ### Claim 13 (depends on 1) The printer gradation correcting method described in claim 1, wherein when there is a region including discontinuous points in a different portion image between a standard image of a color patch image and the outputted color patch image or in a differential image of the outputted color patch image, the region is not made as the measurement region by the measuring device. ### Claim 14 A color patch image, including: a patch-shaped image having a uniform gradation of a predetermined gradation representative value; and gradation fluctuation of a predetermined color component added in the patch-shaped image, wherein the added gradation fluctuation is structured such that a total of gradation fluctuation measured in a measurement region by the color measuring device becomes a predetermined value.