# US 5,706,045 A · Image data resolution enhancing apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,706,045 A - Document ID: US5706045A - Status: Granted - Kind: A - Application number: 08/709,049 - Filed: 1996-09-06 - Granted: 1998-01-06 - Earliest claimed: 1993-01-28 - Assignees: Kabushiki Kaisha Toshiba - Inventors: Nobuhiro Inoue - Web page: https://patentgrep.com/patent/US5706045A ## CPC - H04N 1/40068: {Modification of image resolution, i.e. determining the values of picture elements at new relative positions (H04N1/3935 takes precedence)} - G06K 15/028: {by thermal printers} - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS ## Abstract In a thermal printing apparatus, three consecutive image data items in the main scanning direction is sequentially extracted. When all the three image data items are at level 0 (indicating that no dot is printed) and at level 1 (indicating that a dot is printed), a printing density is determined to be 0 (indicating that no dot is printed) and 3 (indicating that a dot of the highest printing density is printed), respectively. When one of the three image data items is at level 1, the printing density is determined to be 1 (indicating that a dot of the lowest printing density is printed) when the printing density of the preceding printed pixel is any value other than 0. When one or two of the three image data items is or are at level 1, the printing density is determined to be 1 or 2 (indicating that a dot of an intermediate printing density is printed) according to the printing density of the preceding printed pixel. Thus, the printing apparatus is capable of printing image data without the degradation of the image quality, even when the image data whose resolution in the main scanning direction is higher than (e.g., three times as high as) that inherent to the apparatus is supplied. ## Claims ### Claim 1 A printing apparatus which prints image data having a specific resolution by means of a printing head whose resolution in a main scanning direction is 1/k (k is a given integer) of that of the image data, said apparatus comprising: means for extracting k consecutive image data items in the main scanning direction from the image data; means for determining a printing density of a pixel on the basis of a combination of the k image data items extracted by said extracting means and a printing density of a preceding printed pixel; and means for driving the printing head according to the printing density determined by said determining means. ### Claim 2 (depends on 1) An apparatus according to claim 1, wherein said image data is formed of binary image data items; and said determining means comprises means for converting k image data items into a printing density of (k+1) level. ### Claim 3 (depends on 1) An apparatus according to claim 1, wherein the resolution of said printing head is one-third that of the image data; and said determining means determines the printing density to be 0 (indicating that no dot is printed) when three image data items are all at level 0 (indicating that no dot is printed), the printing density to be 1 (indicating that a dot of a lowest printing density is printed) when the printing density of the preceding printed pixel is any value other than 0 and one of three image data items is at level 1 (indicating that a dot is printed), the printing density to be 2 (indicating that a dot of an intermediate printing density is printed) when the printing density of the preceding printed pixel is 0 and one of three image data items is at level 1, the printing density to be 1 when the printing density of the preceding printed pixel is 3 and discrete two of three image data items are at level 1, the printing density to be 2 when the printing density of the preceding printed pixel is any value other than 3 and discrete two of three image data items are at level 1, the printing density to be 2 when two consecutive ones of three image data items are at level 1, and the printing density to be 3 (indicating that a dot of a highest printing density is printed) when three image data items are all at level 1. ### Claim 4 (depends on 1) An apparatus according to claim 1, wherein said printing head is a thermal printing head. ### Claim 5 (depends on 1) An apparatus according to claim 1, further comprising: means for printing a two-dimensional image through a relative movement in a sub-scanning direction of a printing head arranged in a main scanning direction and a printing sheet, the printing means being supplied with image data having j pixels per a length of r in the sub-scanning direction of the printing head; means for supplying to the printing head image data corresponding to 1/j of a printing density corresponding to a line of pixels; means for relatively moving the printing head and the printing sheet by r/j in the sub-scanning direction for each printing; and means for prohibiting supply of image data by said supplying means if the printing density of the line of pixels has already exceeded a printing density corresponding to the image data at each time of printing for the line of pixels. ### Claim 6 A printing apparatus for printing image data having a specific resolution, comprising: a printing head having printing elements arranged in a main scanning direction, the printing elements of the printing head having overlapping portions with areas printed by adjacent printing elements in the main scanning direction, and being arranged so that a size of a printed pixel may change in the main scanning direction as a printing energy changes, and the resolution in the main scanning direction of the printing head being 1/p (p: a given integer) of a resolution in the main scanning direction of the image data; means for extracting p consecutive image data items in the main scanning direction from the image data; means for determining the printing density of a pixel printed by a single printing element on the basis of a combination of the p image data items extracted by said extracting means and a printing density of a preceding pixel; means for applying to the printing head a printing energy corresponding to the printing density determined by said determining means. ### Claim 7 (depends on 6) An apparatus according to claim 6, wherein said printing head is made up of parallelogrammic printing elements arranged at regular intervals. ### Claim 8 (depends on 6) An apparatus according to claim 6, wherein: said image data is made up of binary image data items; and said determining means comprises means for converting p image data items into a printing density of (p+1)-th value. ### Claim 9 (depends on 6) An apparatus according to claim 6, wherein: the resolution in the main scanning direction of the printing head is half that of the image data; and said determining means comprises means for determining the printing density to be 0 (indicating that no dot is printed) when two extracted image data items are all at level 0 (indicating that no dot is printed), the printing density to be 1 (indicating that the dots in the central area of the printing element are printed) when one of two extracted image data items is at level 1 (indicating that a dot is printed), and the printing density to be 2 (the dots in the entire area of the printing element are printed) when two extracted image data items are all at level 1. ### Claim 10 (depends on 6) An apparatus according to claim 6, wherein said printing head is a thermal printing head. ### Claim 11 (depends on 6) An apparatus according to claim 6, further comprising: means for printing a two-dimensional image through a relative movement in a sub-scanning direction of a printing head arranged in a main scanning direction and a printing sheet, the printing means being supplied with image data having j pixels per a length of r in the sub-scanning direction of the printing head; means for supplying to the printing head image data corresponding to 1/j of a printing density corresponding to a line of pixels; means for relatively moving the printing head and the printing sheet by r/j in the sub-scanning direction for each printing; and means for prohibiting supply of image data by said supplying means if the printing density of the line of pixels has already exceeded a printing density corresponding to the image data at each time of printing for the line of pixels.