# US 10,308,021 B2 · Print element substrate, printhead, and image forming apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,308,021 B2 - Document ID: US10308021B2 - Status: Granted - Kind: B2 - Application number: 15/822,729 - Filed: 2017-11-27 - Published: 2018-06-21 - Granted: 2019-06-04 - Earliest claimed: 2016-12-16 - Assignees: Canon Kabushiki Kaisha - Applicants: Canon Kabushiki Kaisha - Inventors: Hiroyasu Nomura; Nobuyuki Hirayama - Web page: https://patentgrep.com/patent/US10308021B2 ## CPC - B41J 2/14129: {Layer structure} - B41J 2/04541: {Specific driving circuit} - B41J 2/04543: {Block driving} - B41J 2/04563: {detecting head temperature; Ink temperature} - B41J 2/0458: {controlling heads based on heating elements forming bubbles} - B41J 2/14153: {Structures including a sensor} - B41J 2002/14354: {Sensor in each pressure chamber} - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS ## Abstract A print element substrate that includes a plurality of heaters and a plurality of temperature sensors provided in correspondence with a plurality of nozzles, comprises: a selecting unit that selects one temperature sensor from the plurality of temperature sensors and output a temperature signal; a determining unit that determines a discharge state of the nozzle based on the temperature signal output by the selecting unit; an outputting unit that, based on a determination result output from the determining unit, externally outputs a signal indicating the discharge state of the nozzle corresponding to the selected temperature sensor; and a masking unit that, in accordance with a change in selection of the temperature sensor by the selecting unit, masks the determination result output from the determining unit to the outputting unit during a predetermined time from a timing of the change. ## Claims ### Claim 1 A print element substrate that includes a plurality of heaters and a plurality of temperature sensors provided in correspondence with a plurality of nozzles, the substrate comprising: a selecting unit configured to select one temperature sensor from the plurality of temperature sensors and output a temperature signal, and change the temperature sensor; a determining unit configured to determine a discharge state of the nozzle based on the temperature signal output by the selecting unit; an outputting unit configured to, based on a determination result output from the determining unit, externally output a signal indicating the discharge state of the nozzle corresponding to the temperature sensor selected by the selecting unit; and a masking unit configured to, in accordance with a change of the temperature sensor by the selecting unit, mask the determination result output from the determining unit to the outputting unit for a predetermined time after the change of the temperature sensor. ### Claim 2 (depends on 1) The substrate according to claim 1, wherein the predetermined time is determined based on a delay time caused by the determining unit. ### Claim 3 (depends on 1) The substrate according to claim 1, wherein the determination result output from the determining unit to the outputting unit is removed by the masking unit for the predetermined time. ### Claim 4 (depends on 1) The substrate according to claim 1, wherein in accordance with the change of the temperature sensor by the selecting unit, a pulsed signal output from the determining unit as a determination result is produced during the predetermined time due to a discontinuous change in the temperature signal at the timing of the change. ### Claim 5 (depends on 1) The substrate according to claim 1, wherein if the discharge state of the nozzle corresponding to the temperature sensor selected by the selecting unit represents normal discharge, a pulsed signal corresponding to the determination result from the determining unit is produced after an elapse of the predetermined time, and if the discharge state of the nozzle corresponding to the temperature sensor selected by the selecting unit is abnormal, the pulsed signal is not produced after the elapse of the predetermined time. ### Claim 6 (depends on 1) The substrate according to claim 1, wherein a timing at which the predetermined time ends is externally provided for the masking unit. ### Claim 7 (depends on 1) The substrate according to claim 1, wherein a timing at which the predetermined time ends is generated by counting a clock signal input to the print element substrate a predetermined number of times. ### Claim 8 (depends on 1) The substrate according to claim 1, wherein the determining unit includes, a filter having a predetermined passband with respect to the temperature signal output by the selecting unit, and a comparator configured to compare a signal via the filter with a predetermined threshold, and output a determination result signal based on a result of the comparison. ### Claim 9 (depends on 8) The substrate according to claim 8, wherein the predetermined time is determined based on a delay time caused by the filter. ### Claim 10 (depends on 8) The substrate according to claim 8, further comprising: a receiving unit configured to externally receive the predetermined threshold and a latch signal; and a latching unit configured to latch, based on the latch signal, the predetermined threshold received by the receiving unit, wherein based on reception of the latch signal, the masking unit starts masking the determination result signal output from the determining unit. ### Claim 11 (depends on 10) The substrate according to claim 10, further comprising a driving unit configured to drive each heater by sequentially applying, to the heater, a first pulse for discharging a liquid from a corresponding one of nozzles and a second pulse which does not reach discharge, wherein the determination result signal output from the determining unit is masked during a predetermined time from a timing at which the first pulse is driven. ### Claim 12 A printhead that includes at least one print element substrate, wherein the print element substrate includes: a plurality of heaters and a plurality of temperature sensors provided in correspondence with a plurality of nozzles; a selecting unit configured to select one temperature sensor from the plurality of temperature sensors and output a temperature signal, and change the temperature sensor; a determining unit configured to determine a discharge state of the nozzle based on the temperature signal output by the selecting unit; an outputting unit configured to, based on a determination result output from the determining unit, externally output a signal indicating the discharge state of the nozzle corresponding to the temperature sensor selected by the selecting unit; and a masking unit configured to, in accordance with a change of the temperature sensor by the selecting unit, mask the determination result output from the determining unit to the outputting unit for a predetermined time after the change of the temperature sensor. ### Claim 13 (depends on 12) The printhead according to claim 12, wherein the predetermined time is determined based on a delay time caused by the determining unit. ### Claim 14 (depends on 12) The printhead according to claim 12, wherein the determination result output from the determining unit to the outputting unit is removed by the masking unit for the predetermined time. ### Claim 15 An image forming apparatus that includes at least one printhead with a print element substrate, wherein the print element substrate includes: a plurality of heaters and a plurality of temperature sensors provided in correspondence with a plurality of nozzles; a selecting unit configured to select one temperature sensor from the plurality of temperature sensors and output a temperature signal, and change the temperature sensor; a determining unit configured to determine a discharge state of the nozzle based on the temperature signal output by the selecting unit; an outputting unit configured to, based on a determination result output from the determining unit, externally output a signal indicating the discharge state of the nozzle corresponding to the temperature sensor selected by the selecting unit; and a masking unit configured to, in accordance with a change of the temperature sensor by the selecting unit, mask the determination result output from the determining unit to the outputting unit for a predetermined time after the change of the temperature sensor. ### Claim 16 (depends on 15) The image forming apparatus according to claim 15, wherein the predetermined time is determined based on a delay time caused by the determining unit. ### Claim 17 (depends on 15) The image forming apparatus according to claim 15, wherein the determination result output from the determining unit to the outputting unit is removed by the masking unit for the predetermined time.