# US 8,770,708 B2 · Inkjet printer and recovery method for a print head > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,770,708 B2 - Document ID: US8770708B2 - Status: Granted - Kind: B2 - Application number: 13/183,654 - Filed: 2011-07-15 - Published: 2011-11-03 - Granted: 2014-07-08 - Earliest claimed: 2005-10-03 - Assignees: Seiko Epson Corporation - Applicants: Hirotaka Miyabayashi; Masashi Fujikawa - Inventors: Hirotaka Miyabayashi; Masashi Fujikawa - Web page: https://patentgrep.com/patent/US8770708B2 ## CPC - H04N 1/40025: {Circuits exciting or modulating particular heads for reproducing continuous tone value scales (H04N1/401, H04N1/407 take precedence)} - B41J 2/16517: {Cleaning of print head nozzles (B41J2/16505, B41J2/1707 take precedence)} - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS ## Abstract An inkjet printer including: a print head for printing by discharging ink droplets from nozzles; a recovery process unit that executes a print head recovery process; a clock unit that counts time; a print operation measuring unit that acquires printing frequency per unit time; and a memory unit that memorizes the printing frequency per unit time; wherein the recovery process unit executes the print head recovery process based on the printing, frequency per unit time in the memory. ## Claims ### Claim 1 An inkjet printer comprising: a print head for printing by discharging ink droplets from nozzles; a recovery process unit that executes a print head recovery process; a clock unit that counts time; a print operation measuring unit that acquires a count of a number of print operations that occur during a time period counted by the clock unit, the time period being a length of time in a day; and a memory unit that memorizes the count; wherein the recovery process unit executes the print head recovery process based on the count in the memory unit; the recovery process unit sets a low print demand period so that the recovery process unit executes the print head recovery process in the low print demand period; and the recovery process unit sets the low print demand period corresponding to the time period having a zero count, except when none of the time periods have a zero count, the recovery process unit sets the low print demand period corresponding to the time period having a count that is less than or equal to a predetermined threshold value. ### Claim 2 (depends on 1) The inkjet printer described in claim 1, wherein the number comprises a number of lines printed during the time period. ### Claim 3 (depends on 1) The inkjet printer described in claim 1, wherein the number comprises a number of print commands during the time period. ### Claim 4 (depends on 1) The inkjet printer described in claim 1, wherein the recovery process unit executes the print head recovery process when the count is zero, or the count is less than or equal to the predetermined threshold value. ### Claim 5 (depends on 1) The inkjet printer described in claim 1, wherein the recovery process unit executes the print head recovery process when printing did not occur for a predetermined time before a start time of the recovery process. ### Claim 6 (depends on 1) The inkjet printer described in claim 1, wherein the print operation measuring unit acquires at least one additional count, each at least one additional count being a number of print operations that occur during a time period subsequent to the time period for a previous count; the memory unit memorizes each of the at least one additional counts; and the recovery process unit executes the print head recovery process based on the at least one additional counts in the memory unit. ### Claim 7 (depends on 1) The inkjet printer described in claim 1, wherein the length of time in the day is predetermined. ### Claim 8 (depends on 1) The inkjet printer described in claim 1, wherein the print operation measuring unit acquires a count of a number of print operations that occur during each of a plurality of additional time periods counted by the clock unit, each of the additional time periods occurring in the day and having a length equal to the length of time in the day; and the memory unit memorizes the count of the number of print operations that occur during each of the plurality of additional time periods. ### Claim 9 (depends on 8) The inkjet printer described in claim 8, wherein the length of time in the day is at least 30 minutes such that the memory unit memorizes no more than 48 counts for the day. ### Claim 10 (depends on 1) The inkjet printer described in claim 1, wherein the print operation measuring unit acquires a count of a number of print operations that occur during each of a plurality of additional time periods counted by the clock unit, each of the additional time periods occurring in a day subsequent to the day and having a length equal to the length of time in the day and corresponding to a same time of day as the length of time in the day; and the memory unit memorizes the count of the number of print operations that occur during each of the plurality of additional time periods. ### Claim 11 (depends on 10) The inkjet printer described in claim 10, wherein the recovery process unit executes the print head recovery process based on the count in the memory unit when the count is less than or equal to a non-zero threshold value. ### Claim 12 An inkjet printer comprising: a print head for printing by discharging ink droplets from nozzles; a recovery process unit that executes a print head recovery process; a clock unit that counts time; a print operation measuring unit that acquires a count of a number of print operations that occur during a time period counted by the clock unit, the time period being a length of time in a day; and a memory unit that memorizes the count; wherein the recovery process unit executes the print head recovery process based on the count in the memory unit; the recovery process unit executes the print head recovery process based on the count in the memory unit when the count is less than or equal to a non-zero threshold value; and the recovery process unit sets the non-zero threshold value based on a previous time period having a lowest non-zero number of printing operations performed by the print head. ### Claim 13 A print head recovery method for an inkjet printer having a print head for printing by discharging ink droplets from nozzles and a recovery process unit for executing a print head recovery process, the recovery method comprising: (a) acquiring a count of a number of print operations that occur during a time period, the time period being a length of time in a day; (b) memorizing the count; and (c) executing the print head recovery process by the recovery process unit based on the memorized count, the method further comprising setting a low print demand period so that the print head recovery process is executed in the low print demand period; and setting the low print demand period corresponding to the time period having a zero count, except when none of the time periods have a zero count, setting the low print demand period corresponding to the time period having a count that is less than or equal to a predetermined threshold value. ### Claim 14 (depends on 13) The print head recovery method described in claim 13, wherein: step (c) comprises executing the print head recovery process when the count is zero, or the count is less than or equal to the predetermined threshold value. ### Claim 15 (depends on 13) The print head recovery method described in claim 13, wherein: step (c) comprises executing the print head recovery process when printing did not occur for a predetermined time before a start time of the print head recovery process. ### Claim 16 (depends on 13) The print head recovery method described in claim 13, further comprising: (d) acquiring at least one additional count, each at least one additional count being a number of print operations that occur during a time period subsequent to the time period for a previous count, (e) memorizing each of the at least one additional counts; and (f) executing the print head recovery process based on the memorized at least one additional counts. ### Claim 17 An inkjet printer comprising: a print head for printing by discharging ink droplets from nozzles; a recovery process unit that executes a print head recovery process; a clock unit that counts time; a print operation measuring unit that acquires a count of a number of print operations that occur during a time period counted by the clock unit, the time period being a length of time in a day; and a memory unit that memorizes the count; wherein the recovery process unit executes the print head recovery process based on the count in the memory unit; the print operation measuring unit also acquires a count of a number of print operations that occur during each of a plurality of time periods counted by the clock unit; and the recovery process unit executes the print head recovery process at a time after passage of the time period and the plurality of time periods, the time being based on a comparison of the count in the memory unit with the acquired counts for each of the plurality of time periods. ### Claim 18 An inkjet printer comprising: a print head for printing by discharging ink droplets from nozzles; a recovery process unit that executes a print head recovery process; a clock unit that counts time; a print operation measuring unit that acquires a count of a number of print operations that occur during each of a plurality of time periods counted by the clock unit; and a memory unit that memorizes each of the counts; wherein the recovery process unit compares each of the counts in the memory unit so as to determine which of the plurality of time periods had a lowest number of print operations occurring therein; and wherein the recovery process unit executes the print head recovery process at a time subsequent to each of the plurality of time periods and corresponding to the time period determined to have the lowest count.