JP2008023987A5 - - Google Patents

Claims (15)

A recording head that applies thermal energy of an electrothermal transducer to a liquid and discharges the liquid from an ejection port,
A drive unit that divides a plurality of electrothermal conversion elements into a plurality of blocks, and that is driven by energization according to recording data in units of each block;
A plurality of temperature detection elements arranged corresponding to each of the plurality of electrothermal conversion elements, for detecting the temperature of each corresponding electrothermal conversion element ;
A constant current source for applying a bias current in common to the plurality of temperature sensing elements;
A first switching element that turns on / off energization of each temperature detection element from the constant current source and a voltage generated at both ends of the temperature detection element by energization of the temperature detection element by the first switching element are taken out. And a detection voltage extracting circuit having a second switching element.   The recording head according to claim 1, further comprising an amplifier circuit that amplifies the detection voltage extracted by the detection voltage extraction circuit.   The recording head according to claim 1, wherein the temperature detection element forms a group of a plurality of units, and the second switching element is provided corresponding to the group.   The recording head according to claim 3, wherein each block of the plurality of electrothermal conversion elements and each block of the plurality of temperature detection elements respectively include the same number of electrothermal conversion elements and temperature detection elements. . The recording head according to claim 1, wherein the second switching element is provided corresponding to each temperature detection element.   Recording data for driving each of the plurality of electrothermal conversion elements, block selection data for selecting the blocks of the plurality of electrothermal conversion elements and the temperature detection element group, and a temperature at which a voltage is extracted by the detection voltage extraction circuit A shift register that receives and holds serial data including element selection data for selecting a detection element, and decodes the block selection data and the element selection data to decode the block, the temperature detection element group, and each temperature. The recording head according to claim 1, further comprising decoding means for generating a signal for selecting the detection element.   2. The recording head according to claim 1, wherein each of the temperature detection elements is disposed immediately below a corresponding one of the electrothermal conversion elements via an insulating layer. A holding circuit for holding the detection voltage amplified by the amplifier circuit;
3. The differential amplifier according to claim 2, further comprising a differential amplifier that amplifies and outputs a difference between a voltage held by the holding circuit and a detection voltage at a next detection timing amplified by the amplifier circuit. Recording head. A voltage generating circuit for generating a voltage corresponding to the temperature detected by the temperature detecting element ;
The recording head according to claim 2, further comprising a differential amplifier that amplifies and outputs a difference between a voltage generated by the voltage generation circuit and a detection voltage amplified by the amplifier circuit. A plurality of amplifiers that amplify the detection voltage by each temperature detection element extracted from the detection voltage extraction circuit by a corresponding offset voltage;
The recording head according to claim 1, further comprising a selection circuit that selects outputs of the plurality of amplifiers. The on / off first and second switching elements, a recording head according to claim 6, characterized in that it is made by data input to the shift register.   The temperature detection element is arranged immediately below the electrothermal conversion element, and the first and second switching elements are arranged in the vicinity of the temperature detection element and arranged at an arrangement interval of the temperature detection elements. The recording head according to claim 1.   The recording head according to claim 2, further comprising: a voltage generation circuit that generates a reference voltage corresponding to the temperature; and a differential amplifier that amplifies a difference between the reference voltage and the detection voltage. A recording head according to any one of claims 2 , 8 , and 9,
Image data for heating and driving each of the plurality of electrothermal conversion elements, block selection data for selecting the blocks of the plurality of electrothermal conversion elements and the temperature detection element group, and a temperature at which a voltage is extracted by the detection voltage extraction circuit Transfer means for transferring serial data including element selection data for selecting a detection element to the recording head;
Drive control means for outputting a signal for driving the electrothermal transducer of the recording head to generate heat;
Temperature detection means for detecting the temperature by inputting the output of the amplifier circuit in synchronization with driving by the drive control means;
A recording apparatus comprising:   The element selection data detects a temperature accompanying heat generation of the electrothermal conversion element driven by the first block when driving a second block different from the first block of the electrothermal conversion element driven by the drive control means. The recording apparatus according to claim 14, wherein the recording apparatus is data for recording.