# US 11,993,080 B2 · Drive circuit of recording head and image recorder > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,993,080 B2 - Document ID: US11993080B2 - Status: Granted - Kind: B2 - Application number: 17/617,780 - Filed: 2019-06-17 - Published: 2022-07-21 - Granted: 2024-05-28 - Earliest claimed: 2019-06-17 - Assignees: Konica Minolta, Inc. - Applicants: Konica Minolta, Inc. - Inventors: Shinichi Kawaguchi; Hajime Nakamura - Web page: https://patentgrep.com/patent/US11993080B2 ## CPC - B41J 2/04541: {Specific driving circuit} - B41J 2/0458: {controlling heads based on heating elements forming bubbles} - B41J 2/04581: {controlling heads based on piezoelectric elements} - B41J 2/04588: {using a specific waveform} - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS ## Abstract A drive circuit of a recording head having a recording element is provided. The drive circuit supplies a load element for recording operation of the recording element with an output signal of electric power according to operation of the load element. The drive circuit includes a voltage amplifier that amplifies a voltage of an analog drive waveform signal for operation of the recording element to generate a drive voltage signal. The voltage amplifier includes amplifiers. Among the amplifiers, at least one of subsequent-stage amplifiers which are a second and subsequent amplifiers from an upstream side includes a signal feedback unit that returns a signal to be output to an input side of the subsequent-stage amplifiers. ## Claims ### Claim 1 A drive circuit of a recording head having a recording element, the drive circuit supplying a load element for recording operation of the recording element with an output signal of electric power according to operation of the load element, and the drive circuit comprising: a voltage amplifier that amplifies a voltage of an analog drive waveform signal for operation of the recording element to generate a drive voltage signal, wherein the voltage amplifier includes amplifiers, and among the amplifiers, at least one of subsequent-stage amplifiers which are a second and subsequent amplifiers from an upstream side includes a signal feedback unit that returns a signal to be output to an input side of the subsequent-stage amplifiers. ### Claim 2 (depends on 1) The drive circuit for the recording head according to claim 1, wherein each of the subsequent-stage amplifiers includes a transistor that performs amplification. ### Claim 3 (depends on 2) The drive circuit for the recording head according to claim 2, wherein the subsequent-stage amplifiers include two emitter ground circuits, and the signal feedback unit connects the two emitter ground circuits. ### Claim 4 (depends on 3) The drive circuit for the recording head according to claim 3, wherein a potential difference between a supplied source voltage and an output voltage of a transistor of the emitter ground circuit at an input end of the subsequent-stage amplifier is equal to or less than a predetermined reference voltage. ### Claim 5 (depends on 2) The drive circuit for the recording head according to claim 2, wherein the subsequent-stage amplifiers include an emitter ground circuit and a cascode circuit, and the signal feedback unit connects a collector on an output side of the cascode circuit to an emitter of the emitter ground circuit. ### Claim 6 (depends on 2) The drive circuit for the recording head according to claim 2, wherein an operational amplifier is used as a preceding-stage amplifier which is a first amplifier among the amplifiers. ### Claim 7 (depends on 1) The drive circuit for the recording head according to claim 1, wherein the signal feedback unit is included in one of the subsequent-stage amplifiers which has a highest amplification factor. ### Claim 8 (depends on 1) The drive circuit for the recording head according to claim 1, further comprising: a current amplifier that amplifies a current of the drive voltage signal and outputs the amplified current as the output signal. ### Claim 9 (depends on 8) The drive circuit of the recording head according to claim 8, further comprising: a feedback unit that negatively feeds back a feedback signal according to a voltage of the output signal to the voltage amplifier. ### Claim 10 (depends on 8) The drive circuit of the recording head according to claim 8, wherein the current amplifier comprises two sets of transistors that amplify a current by push-pull operation. ### Claim 11 (depends on 10) The drive circuit of the recording head according to claim 10, wherein the two sets of transistors are both FETs. ### Claim 12 (depends on 10) The drive circuit of the recording head according to claim 10, wherein the two sets of transistors are both bipolar transistors. ### Claim 13 (depends on 10) The drive circuit of the recording head according to claim 10, further comprising: a bias generation unit that generates a predetermined bias voltage between the drive voltage signals supplied to the two sets of transistors. ### Claim 14 (depends on 13) The drive circuit for the recording head according to claim 13, wherein the bias voltage generated by the bias generator is smaller than a sum of operation threshold voltages of the two sets of transistors. ### Claim 15 (depends on 13) The drive circuit of the recording head according to claim 13, wherein the bias generation unit includes: a bipolar transistor connected between input ends of the two sets of transistors; and resistance elements that connect (i) a base and an emitter and (ii) the base and a collector of the bipolar transistor, respectively. ### Claim 16 (depends on 8) The drive circuit of the recording head according to claim 8, further comprising: a resistance element that includes: one end connected to an output of the current amplifier; and another end that outputs the output signal. ### Claim 17 (depends on 1) An image recorder, comprising: the drive circuit of the recording head according to claim 1; and the recording head to which the output signal is input. ### Claim 18 (depends on 1) The drive circuit for the recording head according to claim 1, wherein the signal feedback unit returns the signal to be output from an output side of the at least one of subsequent stage amplifiers to an input side of the at least one of subsequent stage amplifiers. ### Claim 19 (depends on 1) The drive circuit for the recording head according to claim 1, wherein the signal feedback unit is internal to the at least one of subsequent-stage amplifiers.