JP2010131787A - Substrate for recording head and recording head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate for a recording head in which a range of superheating-temperature controlling by an exothermic resistance element for heating is widened by independently controlling the exothermic resistance element for heating from an exothermic resistance element for delivering ink, and to provide the recording head. <P>SOLUTION: The substrate for the recording head which controls the recording head includes: a plurality of first elements being the exothermic resistance elements for generating heat energy utilized for delivering the ink; a plurality of first driving circuits, which are provided in accordance with respective first elements and drive the first elements; first power source terminals for inputting electric voltages for loading to the first elements; second elements provided separately from the first elements and being exothermic resistance elements for heating the substrate for the recording head; second power source terminals, provided separately from the first power source terminals and inputting electric voltages for loading to the second elements; second driving circuits for feeding electric currents to the second elements; and an electric voltage converting circuit, which converts the electric voltages from the second power source terminals to drive the second driving circuits. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a print head substrate and a print head in which a heat generating resistive element for discharging ink and a drive circuit for driving the same are formed on the same substrate.

  Various methods are known as printer recording methods, and one of the recording methods is an inkjet method. The ink jet recording system has advantages such as non-contact recording on a recording medium such as paper, easy colorization, and excellent quietness. Generally, the viscosity of ink used in an ink jet recording apparatus increases in a low temperature environment. For this reason, in a low temperature environment, phenomena such as a decrease in the volume of ink ejected from the recording head (a variation in ejection amount) and a failure in normal ink ejection (ejection failure) occur.

  In this case, in the recorded image, density unevenness due to ejection amount fluctuation, incomplete dot shape due to ejection failure, and the like are visually recognized, and the recording quality is deteriorated. In addition, if a volatile ink component evaporates and the ink viscosity increases in the ink liquid path in the vicinity of the ejection port of the recording head, ejection failure is likely to occur in the first few ejections. In order to eliminate such variation in ejection amount and ejection failure, the ink jet recording apparatus employs a technique for controlling the heating so that the temperature of the recording head is within a predetermined range before or during the recording operation.

  As a method for heating the recording head, for example, two methods are known. Specifically, a short-pulse heating method in which a discharge heater for discharging ink droplets is driven with a short pulse that does not discharge, and a sub-heater for heating is provided separately from the discharge heater, and ink is supplied. There is a sub-heater heating method in which heating is performed directly or indirectly. In any method, a general temperature adjustment sequence is performed by short pulse heating or sub-heater heating until the target temperature is reached, and when the target temperature is exceeded, heating is terminated. Patent Document 1 discloses a technique in which a sub-heater for performing sub-heater heating is provided as a semiconductor substrate for an ink jet recording head (hereinafter abbreviated as a recording head substrate).

  FIG. 8 shows an example in which the sub-heater of this form is applied to a conventional recording head substrate. Details of a conventional recording element driving circuit and driving system for a recording head substrate are described in Patent Document 2, for example.

  Reference numeral 501 denotes a recording head substrate. Reference numeral 502 denotes a heater that generates thermal energy used for ejecting ink. Reference numeral 503 denotes a switching element that drives each heater 502. Reference numeral 506 denotes an M-bit shift register (S / R) for temporarily storing recording data. Reference numeral 505 denotes a latch circuit that collectively holds the recording data stored in the shift register (S / R) 506. A block selection circuit (decoder) 504 selects a desired block from N blocks formed by the heater 502 and the switching element 503. A heater selection circuit 515 uniquely selects an arbitrary heater 502. Reference numeral 507 denotes a voltage conversion circuit that converts the voltage of the output signal from the heater selection circuit 515 into a voltage for driving the switching element 503. Here, the heater 502, the switching element 503, and the heater selection circuit 515 form one group by N and are divided into M groups 1 to M formed by the N elements. .

  Here, when the clock signal CLK supplied from the printer main body is input to the terminal 509, an M-bit recording data signal that is serially transferred in synchronization therewith is input to the terminal 510. The M-bit recording data signal is sequentially stored in the shift register 506. The serial data is held in the latch circuit 505 in accordance with the latch signal LT input from the latch signal terminal 508. At this time, a signal input to the block selection circuit 504 is also serially transferred following the recording data signal. The block selection circuit 504 converts the input signal into N block selection signals and supplies them to the groups 1 to M. With the above-described configuration, the heater selection circuit 515 arbitrarily selects M × N heaters 502 arbitrarily by taking a logical sum of M print data signals and N block selection signals in a matrix. .

  Reference numeral 530 denotes a VH power supply terminal for inputting a voltage to be applied to the heater 502. Reference numeral 540 denotes a VH power supply line, which connects the VH power supply terminal 530 and the heater 502. Reference numerals 531 and 541 denote a GNDH terminal and a GNDH line, which collect the current flowing through the heater 502. Reference numeral 513 denotes a drive voltage generation circuit (VHT buffer) which serves as a power source for the voltage conversion circuit 507. Reference numeral 532 denotes a VHT power supply terminal that supplies a power supply voltage to the drive voltage generation circuit 513.

  In FIG. 8, the block selection signal 518 and the recording data signal 517 are input to the AND gate which is the heater selection circuit 515, and when these two signals become active, the output of the AND gate becomes active. . FIG. 9 shows a circuit diagram for performing this processing. The voltage amplitude of the output signal of the AND gate is converted into a voltage (second operating voltage) higher than the voltage amplitude (first operating voltage) of the output of the heater selection circuit 515 in the voltage conversion circuit 507. The converted signal is applied to the gate of the switching element 503, and a current is applied to the heater 502 connected to the switching element 503 having a voltage applied to the gate. Thereby, the heater 502 is driven.

  Here, the reason why the voltage is converted to a higher voltage is to increase the voltage applied to the gate of the switching element 503, thereby reducing the on-resistance and allowing the current to flow through the heater with high efficiency. The voltage value is desirably set as high as possible within a range not exceeding the breakdown voltage of the circuit and the gate breakdown voltage of the MOS.

  Next, the drive voltage generation circuit 513 (VHT buffer) will be described with reference to FIG. The drive voltage generation circuit 513 functions to generate a desired voltage (second operating voltage) from the VHT voltage 532.

  The drive voltage generation circuit 513 includes a high voltage nMOS transistor 903, a source follower resistor 904, and voltage dividing resistors 901 and 902 that constitute an nMOS source follower. A voltage obtained by dividing the VHT voltage 532 by the voltage dividing resistors 901 and 902 is applied to the gate of the high voltage nMOS transistor 903, and the output of the source follower is used as the output voltage (second operating voltage). By setting the voltage applied to the gate of the high-breakdown-voltage nMOS transistor 903 by the voltage dividing resistors 901 and 902 to a desired value, the second operating voltage can be converted to a voltage value lower than the heater operating voltage.

  Next, the internal circuit of the voltage conversion circuit 507 and its peripheral circuits will be described with reference to FIG.

  A signal from the heater selection circuit 515 is configured to generate an inverted logic signal by an inverter that operates at a first operating voltage and apply it to the gates of the NMOS transistor and the PMOS transistor that operate at a second operating voltage. . Here, the transistor driven by the second operating voltage needs to be an element having a withstand voltage with respect to the second operating voltage.

Returning to FIG. 8, reference numeral 521 denotes a sub-heater that heats the recording head substrate 501. Reference numeral 522 denotes a MOS transistor, which functions as a sub heat driver that supplies current to the sub heater 521. Reference numeral 523 denotes a SUBHE terminal to which a control terminal of a sub heat driver (MOS transistor) 522 is connected. Here, one terminal of the sub-heater 521 is connected to a VH power supply terminal 530 for applying a voltage to the heater 502. With such a configuration, when a heater driving voltage is applied to the VH power supply terminal 530, the heater driving voltage is also applied to the sub heater 521 at the same time. When an ON signal is supplied to the gate of the sub heat driver 522, a current flows through the sub heater 521 and the recording head substrate 501 is heated during that period. That is, the temperature of the recording head substrate 501 can be controlled by applying a voltage to the VH power supply terminal 530 and turning on the signal SUBHE for an arbitrary period. The sub-heater 521 is disposed at one place or a plurality of places on the substrate, and is formed of a heater material similar to the discharge heater material, Al wiring, diffusion resistance, or the like.
Japanese Patent Laid-Open No. 10-71714 JP 2005-199703 A

  However, in the sub-heater configuration as described above, since the sub-heater 521 and the ink ejection (recording element) heater 502 use the same power supply voltage (VH power supply terminal 530), only the sub-heater 521 is appropriately used. It is difficult to drive with voltage. The sub-heater must heat the temperature of the recording head so that recording can be appropriately performed in any case, and it is necessary to generate a completely different amount of energy at a different timing from the heater for discharging ink. That the sub-heater shares the power supply voltage with the heater means that the energy cannot be adjusted by the voltage. In this case, the energy can be adjusted only by timing control by turning on / off the sub heat driver. For this reason, the degree of freedom in controlling the heating of the recording head is lost, which causes a narrowing of the control range. As a result, the recording quality is degraded.

  In addition, a configuration in which a power source is individually provided for the sub heater is also considered. In this case, the power source of the circuit for controlling the sub heater is the same as the power source for driving the recording element. Therefore, if any noise is mixed into the power supply of the discharge heater while the power supply of the subheater is energized, current may flow to the subheater at a timing different from the original timing, causing problems such as abnormal temperature rise. End up.

  Further, even when the recording head is driven and controlled from the printer main body side, the head temperature control should be performed regardless of the recording operation by the head. For example, even in the case where the start of recording is controlled after the head temperature is set to a certain value before the start of recording, the temperature control by the sub heater cannot be performed unless the heater voltage VH is applied. It gives a constraint. Therefore, cost increases due to complicated control sequences and increased parts.

  Further, in the configuration of the sub-heater and the sub-heat driver as described above, the gate terminal of the sub-heat driver is directly connected to the external terminal SUBHE. For this reason, the power supply voltage (for example, 3.3 V to 5 V) of the logic circuit system that is the signal amplitude of the main device is used as the amplitude of the signal given from the main device to the sub-heater or the like. For this reason, the gate of the MOS transistor, which is a sub heat driver, is driven by the power supply voltage of the logic circuit system, so that the ON resistance is increased and the driving efficiency of the sub heater is deteriorated. Further, if the gate of the MOS transistor is driven at a voltage higher than the power supply voltage of the logic circuit system to reduce the ON resistance, it is necessary to newly provide a power supply different from the power supply of the logic circuit system. Cost increase is inevitable.

  The present invention has been made in view of the above-mentioned problems, and controls the heating resistance element for heating independently of the heating resistance element for ink discharge, and limits the range of overheating and temperature control by the heating resistance element. An object of the present invention is to provide a recording head substrate and a recording head which are widened.

  In order to achieve the above object, one aspect of the present invention is a recording head substrate that controls a recording head, and includes a plurality of heating resistor elements that generate thermal energy used to eject ink. A first element, a plurality of first drive circuits provided corresponding to each of the first elements and driving the first element, and a voltage to be applied to the first element are input. Provided separately from the first power supply terminal and the first element, and provided separately from the second element, which is a heating resistance element for heating the recording head substrate, and the first power supply terminal. A second power supply terminal for inputting a voltage to be applied to the second element; a second drive circuit for supplying a current to the second element; and driving the second drive circuit A voltage conversion circuit for converting a voltage from the second power supply terminal; Characterized in that it Bei.

  Another embodiment of the present invention is a recording head including a recording head substrate, and includes a plurality of first elements that are heating resistance elements for generating thermal energy used to eject ink. A plurality of first drive circuits provided corresponding to the first elements and driving the first elements, and a first power supply terminal for inputting a voltage to be applied to the first elements. And a second element which is provided separately from the first element and which is a heating resistance element for heating the recording head substrate, and is provided separately from the first power supply terminal. A second power supply terminal for inputting a voltage to be applied to the element; a second drive circuit for supplying a current to the second element; and the second power supply for driving the second drive circuit. And a voltage conversion circuit for converting a voltage from the terminal. To.

  According to the present invention, since the heating resistance element for heating is configured to be controlled independently of the heating resistance element for discharging ink, the range of overheating / temperature control by the heating resistance element can be expanded. .

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a recording head substrate and a recording head according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

(Embodiment 1)
FIG. 1 is an example of a plan view of a recording head substrate according to an embodiment of the present invention. The recording head substrate is provided in an ink jet recording apparatus (for example, a printer).

  Reference numeral 101 denotes a recording head substrate. Reference numeral 102 denotes a heating resistance element (hereinafter referred to as a heater), which functions as a first element. The heater 102 generates heat energy used for ejecting ink. Reference numeral 103 denotes a switching element that functions as a first drive circuit that drives each of the first elements. The switching element 103 supplies current to the heaters 102 to drive each heater 102. Reference numeral 106 denotes an M-bit shift register (S / R) for temporarily storing recording data. Reference numeral 105 denotes a latch circuit that collectively holds the recording data stored in the shift register 106. A block selection circuit (decoder) 104 selects a desired block from N blocks formed by the heater 102 and the switching element 103.

  Reference numeral 115 denotes a heater selection circuit that uniquely selects an arbitrary heater 102. Reference numeral 107 denotes a voltage conversion circuit that converts the voltage of the output signal of the heater selection circuit 115 into a voltage for driving the switching element 103. Here, the heater 102, the switching element 103, and the heater selection circuit 115 form one group by N and are divided into M groups 1 to M formed by the N elements. . When a clock signal CLK supplied from the printer main body is input to the terminal 109, an M-bit recording data signal that is serially transferred in synchronization with this is input to the terminal 110. The M-bit recording data signal is sequentially stored in the shift register 106. The serial data is held in the latch circuit 105 in accordance with the latch signal LT input from the latch signal terminal 108. At this time, a signal input to the block selection circuit 104 is also serially transferred following the recording data signal, converted into N block selection signals by the block selection circuit 104, and connected to the groups 1 to M. With the configuration as described above, the heater selection circuit 115 takes a logical sum of M print data signals and N block selection signals in a matrix form, and arbitrarily selects M × N heaters 102 arbitrarily. .

  Reference numeral 130 denotes a VH power supply terminal which functions as a first power supply terminal for inputting a voltage to be applied to the heater 102. Reference numeral 119 denotes a VH power supply line, which is connected from the VH power supply terminal 130 to the heater. Reference numerals 131 and 120 denote a GNDH terminal and a GNDH line, and collect the current flowing through the heater. A drive voltage generation circuit (VHT buffer) 113 serves as a power source for the voltage conversion circuit 107. Reference numeral 132 denotes a VHT power supply terminal that supplies a power supply voltage to the drive voltage generation circuit 113.

  Here, with reference to FIG. 2, an example of the operation timing of the recording element driving circuit composed of the M groups described above will be briefly described. FIG. 2 shows one sequence (one discharge cycle) for making an arbitrary heater selectable once from M × N heaters. Here, the cycle until the same heater is selected to be drivable again is one cycle.

  First, M-bit data corresponding to the recording data is serially transferred to the shift register 106 and the latch circuit 105 as a DATA signal synchronized with the clock signal CLK. When the subsequent latch signal LT becomes “Lo” (low level), the input serial data (recording data signal 117) is transferred and output to the data line. Subsequently, when the latch signal LT becomes “High” (high level), this signal is held in the latch circuit 105. An arbitrary data signal corresponding to the recording data among the M recording data signals 117 becomes “High”.

  Similarly, the X-bit block control signal is also serially transferred to the shift register 106 and the latch circuit 105 in synchronization with the clock signal CLK. Subsequently, when the latch signal LT becomes “High”, an X-bit block control signal is held in the block selection circuit 104. Any one of the N outputs of the block selection signal 118 from the block selection circuit 104 is selected and becomes “High”.

  Of the M printing element driving circuits to which one block selection signal 118 is connected in common, an arbitrary heater 102 is selected by the AND circuit of the heater selection circuit 115. A current IH flows through the selected heater 102 in accordance with the HE signal input from the terminal 111 and the heat enable signal obtained by ANDing the print data signal by the heat circuit 116. Thereby, the heater is driven.

  By repeating the above operation N times sequentially, the M × N heaters 102 are driven in a time-sharing manner at a timing N times M times. Thereby, all the heaters are selected according to the image data. In other words, M × N heaters are divided into M groups composed of N heaters, and the time of one sequence is time-divided at N times so that two or more heaters in the group are not driven simultaneously. To do. Then, control is performed so that the M-bit image data is simultaneously driven within the time-divided time.

  Now, the sub head drive voltage generator 160 is provided on the print head substrate 101. Reference numeral 121 denotes a heating resistance element (hereinafter referred to as a sub-heater) for heating, and functions as a second element. The sub-heater 121 generates heat energy and heats the recording head substrate. Reference numeral 122 denotes a MOS transistor, which functions as a sub heat driver (second drive circuit) for causing a current to flow through the sub heater 121. Reference numeral 150 denotes a terminal SUBHE, which inputs a drive signal for controlling ON / OFF of the sub heater 121. Reference numeral 151 denotes a power supply terminal VSUBH, which functions as a second power supply terminal for inputting a voltage to be applied to the sub heater 121. Reference numeral 163 denotes a buffer circuit which receives a signal from the drive signal terminal SUBHE 150 and transmits it to a subsequent circuit. Reference numeral 161 denotes a first voltage generation circuit that generates the power supply voltage 162 (VSUBLM) of the buffer circuit 163 from the power supply terminal VSUBH151. A voltage conversion circuit 166 receives a signal from the buffer circuit 163 and converts the signal into a signal for driving the gate of the sub heat driver (MOS transistor) 122. Reference numeral 164 denotes a second voltage generation circuit that generates the power supply voltage 165 (VSUBHM) of the voltage conversion circuit 166 from the power supply terminal VSUBH151. For example, if the logic power supply voltage of the printer main body is 3.3V, the VSUBLM 162 that is the output voltage of the first voltage generating circuit 161 is also set to 3.3V. On the other hand, the VSUBHM 165 that is the output voltage of the second voltage generation circuit 164 is set as high as possible without exceeding the breakdown voltage of the circuit and the gate breakdown voltage of the MOS so as to make the ON resistance of the sub heat driver 122 as low as possible. Set as follows. For example, if the breakdown voltage of the circuit and the gate breakdown voltage of the MOS are 16V and 30V, respectively, it is desirable to set VSUBHM165 to about 12V. Then, the voltage dividing resistors in the first voltage generating circuit 161 and the second voltage generating circuit 164 are set to have voltage divisions corresponding to VSUBLM 162 and VSUBHM 165, respectively.

  The GND terminal of the subheat drive voltage generator 160 including these voltage generation circuits is connected to a common GND terminal of the recording head, for example, a GNDH terminal 131 for recovering the current of the heater power supply, or a recording element. It may be connected to the GND terminal for the driving circuit.

  As described above, according to the first embodiment, the power supply terminal VSUBH 151 is provided in the sub heater 121, and power is supplied to the sub heater 121 from a terminal different from the VH power supply terminal 130 that drives the heater 102. That is, the power supply voltage supplied to the sub-heater 121 is different from the VH power supply terminal 130 of the heater 102 for recording purposes. Therefore, the heating / temperature control by the sub heater 121 can be performed independently of the recording operation. As a result, the degree of freedom in overheating and temperature control of the recording head substrate is increased, and the control range can be expanded.

  Further, according to the first embodiment, the voltage conversion for converting the signal amplitude of the signal SUBHE (signal from the drive signal terminal SUBHE150) for controlling ON / OFF of the sub heater 121 into a voltage higher than the signal amplitude of the logic circuit of the printer main body. A circuit is provided. That is, the signal SUBHE (that is, the signal of the drive signal terminal SUBHE 150) is converted into a high voltage for driving the gate of the sub heat driver (MOS transistor) 122 and supplied to the sub heat driver 122. Thereby, the ON resistance of the sub heat driver (MOS transistor) 122 is lowered, and the driving efficiency of the sub heater 121 is improved.

  Further, according to the first embodiment, the first voltage generation circuit 161 generates the power supply voltage 162 of the buffer circuit 163 that receives the signal SUBHE (that is, the signal of the drive signal terminal SUBHE150). The second voltage generation circuit 164 generates the power supply voltage 165 of the voltage conversion circuit 166 that drives the gate of the sub heat driver (MOS transistor) 122. Therefore, it is not necessary to supply a special power supply from the outside. Further, since the second voltage generation circuit 164 generates the power supply voltage to be applied to the voltage conversion circuit 166, even when the recording head is driven and controlled from the printer body side, it is independent of the recording operation by the recording head. Thus, the temperature of the print head substrate can be controlled.

  Furthermore, according to the first embodiment, the power supply voltages of the first voltage generation circuit 161 and the second voltage generation circuit 164 are based on the power supply terminal VSUBH 151 that is the power supply voltage of the sub heater 121. Therefore, these circuits do not operate unless the power supply voltage is supplied from the power supply terminal VSUBH151. That is, all the heating and temperature control by the series of sub-heaters 121 are started only by applying the power supply terminal VSUBH151 and can be ended by turning off the power supply terminal VSUBH151. Thereby, the sub heater 121 and the sub heat driver 122 can be controlled independently of the VH power supply terminal 130.

(Embodiment 2)
Next, Embodiment 2 will be described. FIG. 3 is an example of a plan view of a recording head substrate according to the second embodiment. In addition, the same number is attached | subjected to what fulfills the same function as FIG. 1 which demonstrated Embodiment 1, and the description is abbreviate | omitted.

  An ink supply port 210 supplies ink from the back surface of the recording head substrate 101. In this case, two supply ports are provided in the same substrate. Reference numeral 205 denotes a recording element drive circuit, which includes the heater selection circuit 115, the voltage conversion circuit 107, the switching element 103, and the heater 102 described in the first embodiment. Since these operations are the same as those in FIG. 1, description thereof will be omitted.

  Reference numeral 201 denotes a sub-heater that heats the recording head substrate. The sub-heater 201 according to the second embodiment is provided in parallel with the ink supply port (the arrangement direction of the first elements provided along the supply port) and is disposed so as to surround the recording element drive circuit 205. . Such an arrangement of the sub-heater 201 is suitable for heating the entire recording head substrate 101 on average. For example, AL wiring or the like (for example, aluminum or an alloy containing aluminum) is used as the resistor, and the sub-heater 201 formed by the AL wiring or the like is connected to the sub-heat drive voltage generator 160. As a result, the entire recording head substrate 101 is heated and controlled in a uniform manner. In addition, the temperature can be controlled independently of the recording operation.

  In FIG. 3, the AL wiring serving as the sub-heater 201 is shown passing through the outside of the recording element drive circuit 205, but the invention is not limited to this. For example, the recording head substrate 101 may have a multilayer structure, and as shown in FIG. 4, an AL wiring serving as the sub-heater 201 may be disposed so as to pass between the heater 102 and the switching element 103. In this case, since the vicinity of the ink supply port 210 is heated by the sub-heater 201, there is a high effect in suppressing ejection failure caused by the ink viscosity.

  4 shows an enlarged layout of a plurality of recording element driving circuits 205, and FIG. 5 shows a cross section taken along line A-A 'shown in FIG. Reference numeral 301 denotes a first wiring layer, and reference numeral 410 denotes a heater layer formed together with the first wiring layer. The heater layer is exposed by selectively removing the first wiring layer 301. Thereby, the heater 302 is formed. Reference numeral 412 denotes an interlayer insulating film between the second wiring layer 303 and reference numeral 411 denotes a protective film layer formed on the first wiring layer. A second wiring layer 303 is insulated from the first wiring layer 301 by the interlayer insulating film 412 and is connected to the first wiring layer 301 through the through hole 304. The second wiring layer 303 is formed below the first wiring layer 301.

Reference numeral 413 denotes an interlayer insulating film between the second wiring layer 303 and the recording head substrate 101. Reference numeral 416 denotes a through hole for connecting to the switching element 103 formed in the recording head substrate 101. Here, 201 is a sub-heater made by using the second wiring layer 303 and is arranged between the heater 302 and the switching element 103. With such a configuration, the sub heater 201 can be disposed in the vicinity of the ink supply port 210. (Embodiment 3)
Next, Embodiment 3 will be described. FIG. 6 is an example of a plan view of a recording head substrate according to the third embodiment. In addition, the same number is attached | subjected to what fulfills the same function as FIG. 3 which demonstrated Embodiment 2, and the description is abbreviate | omitted. In FIG. 6, the two ink supply ports are a row and b row, respectively, and the sub-heaters formed by AL wiring or the like surrounding each of them are 201-a and 202-b, respectively. The recording data input terminals corresponding to the respective ink supply ports are denoted by 110-a and 110-b, and the heat signal terminals are denoted by 111-a and 111-b.

  In general inkjet recording heads, high-quality images and high speed are achieved by discharging different color inks from these two ink supply ports or discharging differently deposited ink. . On the other hand, when such driving is performed, individual temperature control may be performed for each supply port.

  Accordingly, the two ink supply ports are respectively designated as a row and b row, and sub-heaters formed by AL wiring or the like surrounding each of them are designated as 201-a and 202-b, respectively. Drive signal terminals SUBHE for inputting signals for controlling ON / OFF of these sub-heaters are 150-a and 150-b. Corresponding to these, two buffer circuits 163, a voltage conversion circuit 166, and a sub heat driver 122 are individually provided. Note that the first voltage generation circuit 161 and the second voltage generation circuit 164 are commonly used.

  In this manner, the timing of heating and temperature control is controlled independently by the drive signal terminals SUBHE 150-a and 150-b provided corresponding to the two sub-heaters, that is, the second elements. The voltage applied to the sub-heater uses one VSUBH terminal 151. As a result, the sub heater can be controlled independently of the power source of the ink discharge heater.

  In the third embodiment, the case where there are two sub-heaters has been described as an example, but three or more sub-heaters may be provided. In that case, a SUBHE terminal and a sub heat driver corresponding to each of them are provided, and the heating / temperature control timing of each sub heater is controlled independently. The voltage applied to the sub-heater controls the sub-heater independently from the power supply of the discharge heater with one VSUBH terminal.

  The above is an example of a typical embodiment of the present invention, but the present invention is not limited to the embodiment described above and shown in the drawings, and can be appropriately modified and implemented without departing from the scope of the present invention. .

  For example, as shown in FIG. 7, a plurality of sub heaters 121 may be provided, arranged at arbitrary positions on the substrate, connected in series, and then connected to the sub heat drive voltage generator 160. With such a configuration, the temperature control can be controlled at an arbitrary position on the recording head substrate.

1 is an example of a plan view of a recording head substrate according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of operation timing of a recording element driving circuit illustrated in FIG. 1. 6 is an example of a plan view of a recording head substrate according to Embodiment 2. FIG. FIG. 6 is a diagram illustrating a part of a layout of a recording head substrate according to a second embodiment. It is a figure which shows an example of the A-A 'cross section shown in FIG. 6 is an example of a plan view of a recording head substrate according to Embodiment 3. FIG. It is an example of the top view of the board | substrate for recording heads concerning deformation | transformation embodiment. It is an example of a plan view of a conventional recording head substrate. It is a figure which shows an example of the detail of the conventional substrate for recording heads. It is a figure which shows an example of the detail of the conventional board | substrate for recording heads. It is a figure which shows an example of the detail of the conventional board | substrate for recording heads.

Explanation of symbols

101 Print Head Substrate 102 Heater 103 Switching Element 104 Block Selection Circuit (Decoder)
105 Latch circuit 106 Shift register (S / R)
107 Voltage conversion circuit 121, 201 Sub heater 122 Sub heat driver 160 Sub heat drive voltage generator

Claims (8)

A recording head substrate for controlling a recording head,
A plurality of first elements that are heating resistance elements for generating thermal energy used to eject ink;
A plurality of first drive circuits provided corresponding to the first elements and driving the first elements;
A first power supply terminal for inputting a voltage to be applied to the first element;
A second element which is provided separately from the first element and is a heating resistance element for heating the recording head substrate;
A second power supply terminal provided separately from the first power supply terminal, for inputting a voltage to be applied to the second element;
A second drive circuit for supplying current to the second element;
A recording head substrate comprising: a voltage conversion circuit that converts a voltage from the second power supply terminal to drive the second drive circuit. The second element is:
The printhead substrate according to claim 1, wherein the printhead substrate is arranged in parallel with an arrangement direction of the plurality of first elements. The recording head substrate according to claim 1, further comprising a drive signal terminal for inputting a drive signal for controlling ON / OFF of a current supplied to the second element. A drive signal terminal for inputting a drive signal for controlling ON / OFF of a current supplied to the second element;
A first voltage generating circuit for generating a voltage based on an input from the second power supply terminal;
A buffer circuit for receiving a drive signal from the drive signal terminal using the voltage generated by the first voltage generation circuit as a power source;
A second voltage generation circuit for generating a voltage for driving the gate of the second drive circuit based on an input from the second power supply terminal;
The voltage conversion circuit includes:
The recording head substrate according to claim 1, wherein the amplitude of the drive signal from the buffer circuit is converted into a voltage generated by the second voltage generation circuit. A plurality of the second elements are provided,
A first voltage generating circuit for generating a voltage based on an input from the second power supply terminal;
A second voltage generation circuit for generating a voltage for driving the gate of the second drive circuit based on an input from the second power supply terminal;
A drive signal terminal which is provided corresponding to each of the second elements and inputs a drive signal for controlling ON / OFF of a current supplied to the second element;
A buffer circuit provided corresponding to each of the second elements and receiving a drive signal from the drive signal terminal using a voltage generated by the first voltage generation circuit as a power source;
The voltage conversion circuit is provided corresponding to each of the second elements,
The recording head substrate according to claim 1, wherein the amplitude of the drive signal from the plurality of buffer circuits is converted into a voltage generated by the second voltage generation circuit. The recording head substrate has a multilayer structure,
The first element is:
Arranged in a different layer from the first drive circuit,
The second element is:
The first element and the first driving circuit are formed in a layer disposed between the layers in which the first element and the first driving circuit are disposed, respectively, and are located below the layer formed by the first element. The recording head substrate according to claim 2. The second element is:
The recording head substrate according to claim 6, comprising aluminum or an alloy containing aluminum. A recording head comprising a recording head substrate,
A plurality of first elements that are heating resistance elements for generating thermal energy used to eject ink;
A plurality of first drive circuits provided corresponding to the first elements and driving the first elements;
A first power supply terminal for inputting a voltage to be applied to the first element;
A second element which is provided separately from the first element and is a heating resistance element for heating the recording head substrate;
A second power supply terminal provided separately from the first power supply terminal, for inputting a voltage to be applied to the second element;
A second drive circuit for supplying current to the second element;
A recording head comprising: a voltage conversion circuit that converts a voltage from the second power supply terminal to drive the second drive circuit.

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