# US 2014/0153975 A1 · Image forming apparatus, color registration method of image forming apparatus, host apparatus, control method of host apparatus, and computer readable recording medium > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0153975 A1 - Document ID: US20140153975A1 - Status: Published application - Kind: A1 - Application number: 14/081,084 - Filed: 2013-11-15 - Published: 2014-06-05 - Earliest claimed: 2012-11-30 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Ki-youn LEE - Web page: https://patentgrep.com/patent/US20140153975A1 ## CPC - G03G 15/5041: {Detecting a toner image, e.g. density, toner coverage, using a test patch (G03G15/553 takes precedence)} - G03G 15/01: for producing multicoloured copies - H04N 1/506: {Reproducing the colour component signals picture-sequentially, e.g. with reproducing heads spaced apart from one another in the subscanning direction} - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A color registration method of an image forming apparatus, a control method of a host device, an image forming apparatus, a host apparatus, and a computer-readable recording medium are provided. The method includes printing a preset test pattern for color registration, scanning the printed test pattern for color registration, detecting the printed test pattern for color registration from a scan image obtained as a result of the scanning, calculating location error values of respective colors, using the detected test pattern for color registration, and performing the color registration using the calculated location error values of respective colors. ## Claims ### Claim 1 A color registration method of an image forming apparatus, comprising: printing a preset test pattern for color registration; scanning the printed test pattern for color registration; detecting the printed test pattern for color registration from a scan image obtained as a result of the scanning; calculating location error values of respective colors, using the detected test pattern for color registration; and performing the color registration using the calculated location error values of respective colors. ### Claim 2 (depends on 1) The color registration method of claim 1, wherein the preset test pattern for color registration comprises a plurality of pairs of a first color line and combined lines of a second color line, a third color line, a fourth color line, a fifth color line, and a second color line in sequence, and the first color is one of cyan C, magenta M, yellow Y, and black K, and the second, third, fourth and fifth colors are different colors from each other with one of each of cyan C, magenta M, yellow Y and black K. ### Claim 3 (depends on 2) The color registration method of claim 2, wherein the detecting the printed test pattern for color registration comprises detecting the printed test pattern for color registration by detecting the first color line from the scan image, and the calculating comprises: calculating median location values of respective color lines constituting the combined lines, and calculating the location error values for respective colors using the calculated median location values of respective color lines. ### Claim 4 (depends on 3) The color registration method of claim 3, wherein the calculating the median location values of respective color lines constituting the combined lines comprises: calculating location values of a first edge and a second edge of the respective color lines; calculating linear equations for the first and second edges, using the calculated location values of the first and second edges; and calculating the median location values based on middle locations of a distance between the calculated linear equations of the first and second edges. ### Claim 5 (depends on 3) The color registration method of claim 3, further comprising compensating distortion of the scan image using the median location values of the second color line at both ends, among the calculated median location values of the combined lines. ### Claim 6 (depends on 3) The color registration method of claim 3, wherein the calculating the location error values comprises: calculating an offset location error value that is an average moving distance of each of the third, fourth and fifth color lines included in the combined lines with respect to the calculated median location value of the second color line; calculating a phase location error value that is a difference of phase in the paper advancing direction of the third, fourth, and fifth color lines included in the combined lines with respect to the calculated median location value of the second color line; and calculating a skew location error value that is a difference of phase in the vertical direction to the paper advancing direction of the third, fourth and fifth color lines included in the combined lines with respect to the calculated median location value of the second color line. ### Claim 7 (depends on 1) The color registration method of claim 1, wherein, if the color registration is performed, further comprising printing the test pattern for color registration that reflects the result of color registration as performed. ### Claim 8 A color registration method of an image forming apparatus, comprising: printing a preset test pattern for color registration; displaying a screen to receive location error values of respective colors that are calculated using the printed test pattern for color registration; and if the location error values are inputted to the displayed screen, performing the color registration using the inputted location error values, wherein the location error values are calculated using a scan image that is generated by scanning at an image reading device the printed test pattern for color registration of the image forming apparatus. ### Claim 9 A control method of a host device, comprising: receiving from an image reading device a scan image that is generated as a result of scanning a test pattern for color registration printed at an image forming apparatus; detecting the printed test pattern for color registration from the scan image; and calculating location error values of respective colors using the detected test pattern for color registration. ### Claim 10 (depends on 9) The control method of claim 9, further comprising displaying the calculated location error values of respective colors on a screen. ### Claim 11 (depends on 9) The control method of claim 9, further comprising transmitting the calculated location error values of respective colors to the image forming apparatus connected to the host device. ### Claim 12 An image forming apparatus, comprising: an image forming unit that prints a preset test pattern for color registration; a scanner that scans the printed test pattern for color registration; and a controller that detects the printed test pattern for color registration from a scan image according to the scanning, calculates location error values of respective colors using the detected test pattern for color registration, and controls the image forming apparatus to perform color registration using the calculated location error values of respective colors. ### Claim 13 (depends on 12) The image forming apparatus of claim 12, wherein the preset test pattern for color registration comprises a plurality of pairs of a first color line and combined lines of a second color line, a third color line, a fourth color line, a fifth color line, and a second color line in sequence, and the first color is one of cyan C, magenta M, yellow Y, and black K, and the second, third, fourth and fifth colors are different colors from each other and each be one of cyan C, magenta M, yellow Y and black K. ### Claim 14 (depends on 13) The image forming apparatus of claim 13, wherein the controller detects the printed test pattern for color registration by detecting the first color line from the scan image, and calculates median location values of respective color lines constituting the combined lines, and calculates the location error values for respective colors using the calculated median location values of respective color lines. ### Claim 15 (depends on 14) The image forming apparatus of claim 14, wherein the controller calculates location values of a first edge and a second edges of the respective color lines, calculates linear equations for the first and second edges, using the calculated location values of the first and second edges, and calculates the median location values based on middle locations of a distance between the calculated linear equations of the first and second edges. ### Claim 16 (depends on 14) The image forming apparatus of claim 14, wherein the controller compensates distortion of the scan image using the median location values of the second color line at both ends, among the calculated median location values of the combined lines. ### Claim 17 (depends on 14) The image forming apparatus of claim 14, wherein the controller calculates the location error values comprising: an offset location error value that is an average moving distance of each of the third, fourth and fifth color lines included in the combined lines with respect to the calculated median location value of the second color line; a phase location error value that is a difference of phase in the paper advancing direction of the third, fourth, and fifth color lines included in the combined lines with respect to the calculated median location value of the second color line; and a skew location error value that is a difference of phase in the vertical direction to the paper advancing direction of the third, fourth and fifth color lines included in the combined lines with respect to the calculated median location value of the second color line. ### Claim 18 An image forming apparatus, comprising: an input that receives a user input with respect to the image forming apparatus; an image forming unit that prints a preset test pattern for color registration; a display that displays a screen to receive location error values of respective colors' that are calculated using the printed test pattern for color registration; and a controller that controls the image forming apparatus to perform color registration using the location error values, if the location error values are inputted to the displayed screen, wherein the location error values are calculated using a scan image that is generated by scanning at an image reading device the printed test pattern for color registration of the image forming apparatus. ### Claim 19 A host device, comprising: a display that displays a screen; a communicator that receives from an image reading device a scan image generated as a result of scanning a printed test pattern for color registration of an image forming apparatus; and a controller that detects the printed test pattern for color registration from the scan image, calculates location error values of respective colors using the detected test pattern for color registration, and controls the display to display the calculated location error values of respective colors on the screen. ### Claim 20 A non-transitory computer readable recording medium recording therein a program code to implement a color registration method of an image forming apparatus, wherein the color registration method comprises: printing a preset test pattern for color registration; scanning the printed test pattern for color registration; detecting the printed test pattern for color registration from a scan image obtained as a result of the scanning; calculating location error values of respective colors, using the detected test pattern for color registration; and performing the color registration using the calculated location error values of respective colors.