# US 11,440,315 B2 · Ink jet recording apparatus and ink jet recording method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,440,315 B2 - Document ID: US11440315B2 - Status: Granted - Kind: B2 - Application number: 16/328,341 - Filed: 2017-08-09 - Published: 2021-09-16 - Granted: 2022-09-13 - Earliest claimed: 2016-08-31 - Assignees: Konica Minolta, Inc. - Applicants: Konica Minolta, Inc. - Inventors: Kenji Mawatari; Masanori Shimazoe; Ryohei Kobayashi - Web page: https://patentgrep.com/patent/US11440315B2 ## CPC - B05C 5/02: {the liquid or other fluent material being discharged through an outlet orifice by pressure, e.g.} from an outlet device in contact or almost in contact, with the work - B41J 2/04516: {preventing formation of satellite drops} - B05D 1/26: performed by applying the liquid or other fluent material from an outlet device in contact with, or almost in contact with, the surface - B05D 3/00: Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials (successively applying liquids or other fluent materials B05D1/36; drying ovens F26B) - B41J 2/04581: {controlling heads based on piezoelectric elements} - B41J 2/04588: {using a specific waveform} - B41J 2/04595: {Dot-size modulation by changing the number of drops per dot} - B41J 2/04596: {Non-ejecting pulses} - B41J 2/2128: {by means of energy modulation (control methods or devices therefor, e.g. driver circuits or control circuits B41J2/04501)} - B41J 2202/06: Heads merging droplets coming from the same nozzle - B05C: APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (spraying apparatus, atomising apparatus, nozzles B05B; plant for applying liquids or other fluent materials to objects by electrostatic spraying B05B5/08) - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS - B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02) ## Abstract There is provided an ink jet recording apparatus including an ink jet head and a drive circuit. The ink jet head forms an image on a recording medium in response to a drive signal applied to multiple piezoelectric elements. The drive signal causes multiple pressure chambers corresponding to the multiple piezoelectric elements to expand or to contract in volume and causes ink in the multiple pressure chambers to be discharged from multiple nozzles. The drive circuit generates a drive signal for discharging multiple liquid droplets to one pixel for combining the multiple liquid droplets together and applies the drive signal to each of the multiple piezoelectric elements of the ink jet head. The drive signal includes multiple discharge pulses which make velocities of tips of respective liquid columns substantially same after a predetermined time from starting of ink discharge from the nozzles. ## Claims ### Claim 1 An ink jet recording apparatus comprising: an ink jet head which forms an image on a recording medium in response to a drive signal applied to multiple piezoelectric elements, the drive signal causing multiple pressure chambers corresponding to the multiple piezoelectric elements to expand or to contract in volume and causing ink in the multiple pressure chambers to be discharged from multiple nozzles; and a drive circuit which generates a drive signal for discharging multiple liquid droplets to one pixel for combining the multiple liquid droplets together and applies the drive signal to each of the multiple piezoelectric elements of the ink jet head, wherein the drive signal includes multiple discharge pulses which make velocities of tips of respective liquid columns substantially same after a predetermined time from starting of ink discharge from the nozzles; wherein, in the drive signal, a last discharge pulse of the multiple discharge pulses is included in a satellite reducing pulse; wherein, the satellite reducing pulse sequentially includes: a first expansion pulse which starts from a reference voltage and causes the multiple pressure chambers to expand in volume; a first contraction pulse which causes the multiple pressure chambers to contract in volume to discharge ink from the multiple nozzles; a second expansion pulse which causes the multiple pressure chambers to expand in volume; and a second contraction pulse which causes the multiple pressure chambers to contract in volume, wherein a top voltage of the first contraction pulse is higher than the reference voltage, wherein the second expansion pulse is applied within 1 AL from starting of the first contraction pulse, and wherein the second contraction pulse is applied within 1 AL from starting of the second expansion pulse. ### Claim 2 (depends on 1) The ink jet recording apparatus according to claim 1, wherein, in the drive signal, an absolute value of voltage from a bottom voltage to a reference voltage for each of the multiple discharge pulses is kept constant, and wherein the velocities of tips of respective liquid columns is substantially same by adjustment of at least one standby time between the multiple discharge pulses. ### Claim 3 (depends on 2) The ink jet recording apparatus according to claim 2, wherein, in the drive signal, if a first standby time of the at least one standby time is less than 0.5 AL, a subsequent standby time is set to be sequentially longer, and if a first standby time of the at least one standby time is 0.5 AL or more, a subsequent standby time is set to be sequentially shorter. ### Claim 4 (depends on 2) The ink jet recording apparatus according to claim 2, wherein, in the drive signal, all of the at least one standby time between the multiple driving pulses is 0.5 AL or less. ### Claim 5 (depends on 1) The ink jet recording apparatus according claim 1, wherein the velocities of tips of respective liquid columns is substantially same by adjustment of the drive signal, wherein, in the drive signal, an absolute value of voltage from a bottom voltage to a reference voltage for each of the multiple discharge pulses other than a last discharge pulse is adjusted so as to be equal to or less than the absolute value of a preceding discharge pulse. ### Claim 6 (depends on 5) The ink jet recording apparatus according to claim 5, wherein, in the drive signal, a voltage of a discharge pulse after a first discharge pulse of the multiple discharge pulses is lower than a voltage of the first discharge pulse. ### Claim 7 (depends on 6) The ink jet recording apparatus according to claim 6, wherein, in the drive signal, among all voltages from a bottom voltage to a reference voltage for the multiple discharge pulses, a voltage for a last discharge pulse of the multiple discharge pulses is the largest. ### Claim 8 An ink jet recording apparatus comprising: an ink jet head which forms an image on a recording medium in response to a drive signal applied to multiple piezoelectric elements, the drive signal causing multiple pressure chambers corresponding to the multiple piezoelectric elements to expand or to contract in volume and causing ink in the multiple pressure chambers to be discharged from multiple nozzles; and a drive circuit which generates a drive signal for discharging multiple liquid droplets to one pixel for combining the multiple liquid droplets together and applies the drive signal to each of the multiple piezoelectric elements of the ink jet head, wherein the drive signal includes multiple discharge pulses which make velocities of tips of respective liquid columns substantially same after a predetermined time from starting of ink discharge from the nozzles, wherein, in the drive signal, a last discharge pulse of the multiple discharge pulses is included in a satellite reducing pulse, wherein, the drive signal includes the multiple discharge pulses and the satellite reducing pulse, wherein a pulse width of the respective multiple discharge pulses is 1.0 to 1.3 times of AL, wherein a standby time between one of the multiple discharge pulses and another of the multiple discharge pulses is 0.3 to 0.5 times of AL, wherein a standby time is longer than or has a same length as a preceding standby time, and wherein a last discharge pulse of the multiple discharge pulses includes a satellite reducing pulse. ### Claim 9 An ink jet recording method comprising: forming an image on a recording medium in response to a drive signal applied to multiple piezoelectric elements, causing multiple pressure chambers corresponding to the multiple piezoelectric elements to expand or to contract in volume and causing ink in the multiple pressure chambers to be discharged from multiple nozzles; and generating a drive signal for discharging multiple liquid droplets to one pixel for combining the multiple liquid droplets together and applying the drive signal to each of the multiple piezoelectric elements of the ink jet head, wherein the drive signal includes multiple discharge pulses which make velocities of tips of respective liquid columns substantially same after a predetermined time from starting of ink discharge from the nozzles; wherein, in the drive signal, a last discharge pulse of the multiple discharge pulses is included in a satellite reducing pulse; wherein, the satellite reducing pulse sequentially includes: a first expansion pulse which starts from a reference voltage and causes the multiple pressure chambers to expand in volume; a first contraction pulse which causes the multiple pressure chambers to contract in volume to discharge ink from the multiple nozzles; a second expansion pulse which causes the multiple pressure chambers to expand in volume; and a second contraction pulse which causes the multiple pressure chambers to contract in volume, wherein a top voltage of the first contraction pulse is higher than the reference voltage, wherein the second expansion pulse is applied within 1 AL from starting of the first contraction pulse, and wherein the second contraction pulse is applied within 1 AL from starting of the second expansion pulse. ### Claim 10 (depends on 9) The ink jet recording method according to claim 9, wherein, in the drive signal, an absolute value of voltage from a bottom voltage to a reference voltage for each of the multiple discharge pulses is kept constant, and wherein the velocities of tips of respective liquid columns is substantially same by adjustment of at least one standby time between the multiple discharge pulses. ### Claim 11 (depends on 10) The ink jet recording apparatus according to claim 10, wherein, in the drive signal, if a first standby time of the at least one standby time is less than 0.5 AL, a subsequent standby time of the at least one standby time is sequentially lengthened, and if a first standby time of the at least one standby time is 0.5 AL or more, a subsequent standby time of the at least one standby time is sequentially shortened. ### Claim 12 An ink jet recording method comprising: forming an image on a recording medium in response to a drive signal applied to multiple piezoelectric elements, causing multiple pressure chambers corresponding to the multiple piezoelectric elements to expand or to contract in volume and causing ink in the multiple pressure chambers to be discharged from multiple nozzles; and generating a drive signal for discharging multiple liquid droplets to one pixel for combining the multiple liquid droplets together and applying the drive signal to each of the multiple piezoelectric elements of the ink jet head, wherein the drive signal includes multiple discharge pulses which make velocities of tips of respective liquid columns substantially same after a predetermined time from starting of ink discharge from the nozzles, wherein, in the drive signal, a last discharge pulse of the multiple discharge pulses is included in a satellite reducing pulse, wherein, the drive signal includes the multiple discharge pulses and the satellite reducing pulse, wherein a pulse width of the respective multiple discharge pulses is 1.0 to 1.3 times of AL, wherein a standby time between one of the multiple discharge pulses and another of the multiple discharge pulses is 0.3 to 0.5 times of AL, wherein a standby time is longer than or has a same length as a preceding standby time, and wherein a last discharge pulse of the multiple discharge pulses includes a satellite reducing pulse.