Printing element substrate and temperature detection device

Abstract

The present disclosure relates to a printing element substrate and a temperature detection device. A printing element substrate includes: a printing element that generates thermal energy for ejecting liquid; and a temperature detection element circuit that includes a temperature detection element arranged corresponding to each of the printing elements, and reads temperature information by selectively energizing one of the temperature detection elements, wherein the temperature detection element circuit includes: a signal processing part that outputs a selection signal having a second voltage amplitude greater than the first voltage amplitude based on an input signal having a first voltage amplitude; a selection switch that is arranged for each of the plurality of temperature detection elements and selects the temperature detection element; and a first reading switch that is arranged for each of the plurality of temperature detection elements and reads a voltage of a terminal of one of the temperature detection elements selected by the selection switch, and wherein the selection switch and the first reading switch are driven by using the selection signal.

Description

Technical Field

[0001] The present disclosure relates to a printing element substrate and a temperature detection device. Background Art

[0002] Japanese Patent No. 5474136 discloses a printing element substrate capable of detecting the temperature of a printing element. The printing element substrate includes a plurality of temperature detection elements provided corresponding to each of a plurality of printing elements. In the disclosed substrate, a selection switch for selecting the temperature detection element and a read switch for reading the terminal voltage of the temperature detection element selected by the selection switch are provided for each temperature detection element.

[0003] In such a substrate, the terminal voltages at both terminals of the temperature detection element are read out as a temperature detection signal (temperature information). Based on the temperature detection signal, a printing element having an ejection failure can be determined. Summary of the invention

[0004] By increasing the terminal voltage of the temperature detection element, the S / N ratio of the temperature detection signal can be increased, and therefore, the accuracy of the judgment of the ejection failure can be improved. In order to increase the terminal voltage of the temperature detection element, it is necessary to increase the power supply voltage to increase the operating range of the current source for supplying a constant current to the temperature detection element. In this case, the terminal voltage of the temperature detection element may not be accurately read unless the control voltage of the selection switch or the read switch is amplified according to the expansion of the operating range of the current source. Patent No. 5474136 does not describe such amplification of the control voltage of the selection switch or the read switch.

[0005] An object of the present disclosure is to increase the S / N ratio and accurately read the terminal voltage of a temperature detection element.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present disclosure, a printing element substrate according to one aspect of the present disclosure includes: a plurality of printing elements, configured to generate thermal energy for ejecting liquid; and a temperature detection element circuit, including a plurality of temperature detection elements arranged corresponding to each of the plurality of printing elements, configured to read temperature information by selectively energizing one of the plurality of temperature detection elements, wherein the temperature detection element circuit includes: a signal processing part, configured to output a selection signal having a second voltage amplitude greater than the first voltage amplitude based on an input signal having a first voltage amplitude; a selection switch, arranged for each of the plurality of temperature detection elements, configured to select the temperature detection element; and a first reading switch, arranged for each of the plurality of temperature detection elements, configured to read the voltage of a terminal of one of the temperature detection elements selected by the selection switch, and wherein the selection switch and the first reading switch are driven by using the selection signal.

[0007] In addition, according to another aspect of the present disclosure, a temperature detection device includes: a temperature detection element; a current source configured to apply a constant current to the temperature detection element; a first MOS transistor, wherein one of two terminals other than a gate terminal is connected to one of the terminals of the temperature detection element, and the other of the two terminals is connected to the current source, and a selection signal is supplied to the gate terminal; and a second MOS transistor, wherein one of two terminals other than the gate terminal is connected to a line connecting one of the terminals of the temperature detection element and one terminal of the first MOS transistor, and a selection signal is supplied to the gate terminal, wherein a voltage amplitude value of the selection signal is amplified so that a value obtained by subtracting a threshold voltage between a gate terminal and one terminal of the second MOS transistor from a voltage applied to the gate terminal becomes greater than a value of a terminal voltage generated at one of the terminals of the temperature detection element when a constant current is applied to the temperature detection element via the first MOS transistor.

[0008] Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1A is a diagram schematically showing the configuration of a printing element substrate according to the first embodiment of the present disclosure.

[0010] Figure 1B It is schematically shown Figure 1A A diagram of a configuration of a cross-sectional view in section AA of a printing element substrate shown in FIG.

[0011] Figure 2A It is a diagram for explaining wiring between a printing element substrate and a control device.

[0012] Figure 2B is a diagram for explaining wiring between a printing element substrate and a power supply device.

[0013] Figure 3 is a circuit diagram showing the configuration of a printing element substrate.

[0014] Figure 4A is a diagram for explaining the configuration of a printing element circuit.

[0015] Figure 4B is a diagram for explaining the configuration of a printing element circuit.

[0016] Figure 5 is a block diagram showing the configuration of a temperature detection element circuit.

[0017] Figure 6 is a circuit diagram showing the configuration of a voltage conversion circuit for one segment.

[0018] Figure 7 is a circuit diagram showing the configuration of a segment circuit for a temperature detection element of one segment.

[0019] Figure 8 is a timing chart illustrating the operation of the printing element substrate.

[0020] Fig.9A is a diagram for explaining the operating voltage range of a temperature sensing element circuit.

[0021] Fig. 9B is a diagram for explaining the operating voltage range of a temperature sensing element circuit.

[0022] Fig. 9C is a diagram for explaining the operating voltage range of a temperature sensing element circuit.

[0023] Fig.9D is a diagram for explaining the operating voltage range of a temperature sensing element circuit.

[0024] Fig. 10A is a diagram for explaining the operating voltage range of the temperature detection element circuit of the comparative example.

[0025] Fig. 10B is a diagram for explaining the operating voltage range of the temperature detection element circuit of the comparative example.

[0026] Fig.11 is a block diagram showing a configuration of a common power supply between a segment circuit of a printing element and a segment circuit of a temperature detection element.

[0027] Fig. 12A is a diagram for explaining the structure of a printing element substrate according to the second embodiment of the present disclosure.

[0028] Fig. 12B : is a diagram for explaining the structure of a printing element substrate according to the second embodiment of the present disclosure.

[0029] Fig.13 The configuration of a recording element substrate according to the third embodiment of the present disclosure is illustrated. DETAILED DESCRIPTION

[0030] Embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. However, the components described in the embodiments are merely examples and are not intended to limit the scope of the present disclosure to them.

[0031] <First Embodiment>

[0032] Figure 1A is a diagram schematically showing the configuration of a printing element substrate 101 according to the first embodiment of the present disclosure. Figure 1Ais an external view of the printing element substrate 101 when viewed from the ejection port 104 side. Figure 1B is schematically shown along Figure 1A 1 is a cross-sectional view of a cross-sectional view of the printing element substrate 101 taken along line AA in FIG.

[0033] like Figure 1A As shown in FIG. 1 , a channel forming member 103 is provided on a silicon substrate 102. The channel forming member 103 is made of a photosensitive resin or the like and has a plurality of ejection ports 104 for ejecting a liquid such as ink. A plurality of terminals 105 electrically connected to external electric wires are formed on the upper surface of the silicon substrate 102. Here, the ejection ports 104 are arranged in a line, but the number of ejection ports 104 and the number of lines can be appropriately changed.

[0034] like Figure 1B As shown in FIG. 1 , a printing element 112 for generating thermal energy for ejecting liquid and a temperature detection element 111 are provided in a region facing the ejection port 104. Specifically, an insulating film 106, a wire layer 107, and an interlayer insulating film 108 are sequentially laminated on the silicon substrate 102. The wire layer 107 includes wires 107a to 107d made of aluminum or the like. The temperature detection element 111 is formed on the interlayer insulating film 108. The temperature detection element 111 is a thin film resistor made of titanium, a titanium nitride laminated film, or the like.

[0035] Conductive plugs 114a, 114b made of tungsten or the like are provided to penetrate the interlayer insulating film 108. One end of the temperature detection element 111 is electrically connected to the wire 107a via the conductive plug 114a, and the other end of the temperature detection element 111 is electrically connected to the wire 107b via the conductive plug 114b.

[0036] The interlayer insulating film 109 is laminated on the interlayer insulating film 108 on which the temperature detection element 111 is formed. The printing element 112 is formed on the interlayer insulating film 109. The printing element 112 is a heating resistor made of a tantalum silicon nitride film or the like. Conductive plugs 115a, 115b made of tungsten or the like are provided to penetrate the interlayer insulating film 108 and the interlayer insulating film 109. One end of the printing element 112 is electrically connected to the electric wire 107c via the conductive plug 115a, and the other end of the printing element 112 is electrically connected to the electric wire 107d via the conductive plug 115b.

[0037] On the interlayer insulating film 109 on which the printing element 112 is formed, a protective film 110 such as a silicon nitride film is laminated, and a cavitation-resistant film 113 such as tantalum is formed on the protective film 110. Although the temperature detection element 111 is disposed directly below the printing element 112 via the interlayer insulating film 109, the position of the temperature detection element is not limited to this structure. The temperature detection element 111 may be formed in the same layer as the printing element 112, or may be disposed above the printing element 112 via an interlayer insulating film.

[0038] Figure 2A and Figure 2B 1 is a diagram for explaining electric wires between the printing element substrate 101 and the control device 201 and electric wires between the printing element substrate 101 and the power supply device 300 . Figure 2A 2 is a diagram showing connections between the printing element substrate 101 and the control device 201 . Figure 2B 3 is a diagram showing connections between the printing element substrate 101 and the power supply device 300 .

[0039] like Figure 2A As shown in , the printing apparatus includes a control device 201 for controlling the printing element substrate 101. The control device 201 generates a signal (including printing control information, printing information, and ejection check control information) for controlling the ejection operation of the printing element substrate 101. For example, the control device 201 outputs a block signal LT, a transmission clock signal CLK, a serial data signal D of control information, a serial data signal Do of determination data, and a transmission clock signal CLK2. Here, the block signal LT marks a block time for time-division driving of a plurality of printing elements 112 in units of blocks. The transmission clock signal CLK2 is a clock signal for transmitting the serial data signal Do.

[0040] like Figure 2B As shown in FIG. 1 , the printing apparatus includes a power supply device 300 for supplying power to a printing element substrate 101. The power supply device 300 has a power supply 301, a power supply 302, and a power supply 303. The power supply device 300 supplies a voltage VH (24V), a voltage VHT (5V), and a voltage VDD (3.3V) to the printing element substrate 101. In addition to VH, VHT, and VDD, a ground GNDH corresponding to VH and a ground VSS corresponding to each of VDD and VHT are provided between the power supply device 300 and the printing element substrate 101. VH, VHT, and VDD may be referred to as positive power supply voltages, and VSS may be referred to as negative power supply voltages.

[0041] Figure 33 is a circuit diagram showing the configuration of the printing element substrate 101. The printing element substrate 101 includes a data input circuit 304, a printing element circuit 305, a temperature detection element circuit 306, a current source 307, and a check circuit 308. Here, the printing element circuit 305 includes a plurality of printing elements 112 arranged in a row, and the temperature detection element circuit 306 includes a temperature detection element 111 corresponding to each printing element 112. For example, the temperature detection element 111 is disposed in the vicinity of the printing element 112.

[0042] The power supply 301 supplies a power supply voltage VDD to the printing element substrate 101. The power supply 302 supplies a power supply voltage VHT to the printing element substrate 101. The power supply 303 supplies a power supply voltage VH to the printing element substrate 101. The temperature detection element circuit 306 is driven by using the power supply voltage VDD and the power supply voltage VHT. The printing element circuit 305 is driven by using the power supply voltage VH, the power supply voltage VDD, and the power supply voltage VHT. The current source 307 is driven by the power supply voltage VHT. The current source 307 supplies a constant current Is to the temperature detection element circuit 306.

[0043] The data input circuit 304 receives the block signal LT, the transmission clock signal CLK1 and the serial data signal D generated by the control device 201. The data input circuit 304 expands the data and sends the signal to the circuit of the printing element substrate 101. For example, the data input circuit 304 supplies the signals l_lt, clk_h, d_h and he to the printing element circuit 305. According to the signals l_lt, clk_h, d_h and he, the printing element circuit 305 is driven in a time-division manner. The signal l_lt is a latch signal for the internal circuit, which is generated from the trailing edge of the block signal LT having a predetermined pulse width. The signal clk_h corresponds to the transmission clock signal CLK1. The signal d_h is used to send the data (serial data) driven by time division. The signal he is an applied signal for driving the printing element 112.

[0044] The data input circuit 304 converts the signals l_lt, clk_s, d_s for The temperature detection element circuit 306 and the inspection circuit 308 should be provided. The signals l_lt, clk_s and d_s are respectively a latch signal, a transmission clock signal and serial data. The latch signal l_lt, the transmission clock signal clk_s and the serial data d_s correspond to the latch signal l_lt, the transmission clock signal clk_h and the serial data d_h respectively.

[0045] The temperature detection element circuit 306 reads temperature information by selectively energizing one of the plurality of temperature detection elements 111. In the temperature detection element circuit 306, the temperature detection element 111 is selected based on the latch signal l_lt, the transmission clock signal clk_s, and the serial data d_s, and the selected temperature detection element 111 is connected to the current source 307. The terminal voltages Va and Vb at both ends of the temperature detection element 111 are output to the inspection circuit 308. The terminal voltage Va is a voltage generated at one terminal (a terminal on the high potential side) of the temperature detection element 111, and the terminal voltage Vb is a voltage generated at the other terminal (a terminal on the low potential side) of the temperature detection element 111.

[0046] In the inspection circuit 308, parameters for adjusting the inspection conditions are set based on the latch signal l_lt, the transmission clock signal clk_s, and the serial data d_s, and the timing of the inspection is determined. The inspection circuit 308 receives the temperature waveform input through the terminal voltages va and vb at both ends of the temperature detection element 111. The inspection circuit 308 performs signal processing and determination processing, and outputs determination data for each block time LT as a serial data signal Do synchronized with the serial transmission clock signal CLK2.

[0047] Figure 4A and Figure 4B 305 is a diagram for explaining the configuration of the printing element circuit 305 . Figure 4A 305 is a block diagram showing the configuration of the printing element circuit 305 . Figure 4B 8 is a circuit diagram showing a fragment circuit 802 for a printing element of one fragment. Figure 4A and Figure 4B In the example, the printing element 402 and Figure 1B The printing element 112 shown in FIG.

[0048] like Figure 4A As shown in , the printing element circuit 305 has segments seg0 to seg511. The segments seg0 to seg511 correspond to a configuration in which 512 printing elements 402 are arranged in a row, and each segment has a printing element 402 and a drive switch 403. One terminal of the printing element 402 is connected to a power line 401a, which is a common wire for a power supply voltage VH. The other terminal of the printing element 402 is connected to one terminal of the drive switch 403. The other terminal of the drive switch 403 is connected to a ground line 401b, which is a common wire for a ground GNDH. The ground line 401b is a return destination for the power supply voltage VH.

[0049] The printing element circuit 305 includes a switch driving circuit 404 for driving the driving switches 403 of the segments seg0 to seg511, and a printing element selecting circuit 405. The switch driving circuit 404 and the printing element selecting circuit 405 are respectively connected to a power supply line of a power supply voltage VDD and a ground line of a ground VSS. The switch driving circuit 404 is also connected to a power supply line of a power supply voltage VHT.

[0050] The printing element selection circuit 405 includes a shift register and a decoder. The printing element selection circuit 405 receives a latch signal l_lt, a transmission clock signal clk_h, serial data d_h, and an application signal he, and generates a row signal and a column signal for time division driving. The printing element selection circuit 405 outputs an on / off signal en obtained by logical AND of the row signal and the column signal. The voltage amplitude of the on / off signal en corresponds to the voltage value of the power supply voltage VDD.

[0051] The switch driving circuit 404 amplifies the voltage amplitude of the on / off signal en output from the printing element selection circuit 405. Specifically, the switch driving circuit 404 converts the on / off signal en having a small amplitude with a voltage amplitude value corresponding to the power supply voltage VDD into a driving signal h having a large amplitude with a voltage amplitude value corresponding to the power supply voltage VHT. The driving signal h includes driving signals h0 to h511 corresponding to the segments seg0 to seg511. According to the driving signal h0, the driving switch 403 of the segment seg0 is turned on / off. Similarly, according to the driving signals h1 to h511, the driving switches 403 of the segments seg1 to seg511 are turned on / off.

[0052] exist Figure 4B In the fragment circuit 802 of the printing element shown in FIG. 8 , the switch driving circuit 404 is composed of an inverter operated using a power supply voltage VDD and an inverter operated using a power supply voltage VHT. The switch driving circuit 404 outputs a drive signal h obtained by boosting an on / off signal en. The drive switch 403 includes a metal oxide semiconductor (MOS) transistor 403a. The drain terminal of the MOS transistor 403a is connected to the printing element 402. The source terminal of the MOS transistor 403a is connected to the ground line of the ground GNDH. The drive signal h output from the switch driving circuit 404 is supplied to the gate terminal of the MOS transistor 403a. The MOS transistor 403a is turned on / off according to the drive signal h.

[0053] Figure 53 is a block diagram showing the configuration of the temperature detection element circuit 306. The temperature detection element circuit 306 includes a shift register 501, a voltage conversion circuit 502, a decoder 503 and a fragment circuit 504 of the temperature detection element. The power supply voltage VDD is supplied to the shift register 501 and the decoder 503 to process the input / output signal of the small amplitude. Here, the power supply voltage VDD is 3.3V. The shift register 501 obtains the selection information of the temperature detection element 111 through the latch signal l_lt, the transmission clock signal clk_s and the serial data d_s from the data input circuit 304, and outputs 9-bit selection data a0 to a8. The decoder 503 receives the selection data a0 to a8 and outputs the selection signals lv0 to lv511 for selecting the temperature detection element circuit. The temperature detection element circuit 306 can be referred to as a temperature detection device. The voltage conversion circuit 502 and the decoder 503 can be referred to as a signal processing unit.

[0054] The voltage conversion circuit 502 operates when the power supply voltage VDD and the power supply voltage VHT are applied, and converts an input signal having a small amplitude corresponding to the power supply voltage VDD into a signal having a large amplitude corresponding to the power supply voltage VHT. Here, the power supply voltage VDD is 3.3V and the power supply voltage VHT is 5V.

[0055] The voltage conversion circuit 502 receives selection signals lv0 to lv511 having a voltage amplitude value of 3.3 V, and outputs selection signals hv0 to hv511 having a voltage amplitude value of 5 V. The power supply voltage VHT is the same as the power supply voltage supplied to the switch driving circuit 404 in the printing element circuit 305 .

[0056] The segment circuit 504 of the temperature detection element has 512 segments corresponding to the segments seg0 to seg511 of the printing element circuit 305, and each segment is provided with a temperature detection element 111 corresponding to the printing element 402. The segment circuit 504 operates when the power supply voltage VHT is applied, receives the selection signals lv0 to lv511 from the decoder 503, and receives the selection signals hv0 to hv511 from the voltage conversion circuit 502. In the segment circuit 504, 1 segment among the 512 segments is selected according to the selection signals lv0 to lv511 and hv0 to hv511, and a constant current Is is supplied to the temperature detection element 111 through the wire. At the same time, the terminal voltages va and vb at both ends of the temperature detection element 111 are output via the wire.

[0057] Figure 6 : is a circuit diagram showing the configuration of the voltage conversion circuit 502 for 1 segment. The voltage conversion circuit 502 has a front-stage part 600 that operates by using the power supply voltage VDD and a boosting part 601 that operates by using the power supply voltage VHT.

[0058] The front stage part 600 includes two inverters supplied with power supply voltage VDD, and each inverter includes a PMOS transistor and an NMOS transistor. The inverter in the front stage generates an inverted signal of the selection signal 1v. The inverted signal is input to the inverter of the subsequent stage and is also input to the boosting part 601. The inverted signal is inverted again by the inverter of the subsequent stage and then input to the boosting part 601.

[0059] The boosting section 601 is composed of a plurality of PMOS transistors and a plurality of NMOS transistors. The boosting section 601 is composed of a symmetrical inverter circuit, but unlike the front-stage section 600, the PMOS transistor is connected in series to the terminal side of the power supply voltage VHT. The gate of each PMOS transistor is connected to the output terminal of the relative inverter circuit. Therefore, when the output of one circuit is "H" (5V), the gate of the relative PMOS transistor becomes 5V, and the output of the circuit becomes "L" (0V). When the output of the circuit becomes "L" (0V), the gate of the relative PMOS transistor becomes 0V, the PMOS transistor is turned on, and the output of the circuit becomes "H" (5V). Through this operation, a selection signal hv having an amplitude value of the power supply voltage VHT is generated.

[0060] Figure 7 1 is a circuit diagram showing the configuration of a segment circuit 504 of a temperature detection element for one segment. The segment circuit 504 of the temperature detection element has segments seg0 to seg511, and each segment has a selection switch 701, a temperature detection element 702, a first read switch 704, a second read switch 705, and a resistor 703. The temperature detection element 702 is connected to the Figure 1B The select switch 701, the first read switch 704, and the second read switch 705 are all made of NMOS transistors.

[0061] The drain terminal of the selection switch 701 is connected to the common wire 504-1 of the constant current Is. The source terminal of the selection switch 701 is connected to one terminal of the temperature detection element 702. The source terminal of the first read switch 704 is connected to a line connecting the source terminal of the selection switch 701 and one terminal of the temperature detection element 702. The drain terminal of the first read switch 704 is connected to the common wire 504-2 for reading the terminal voltage va.

[0062] The other terminal of the temperature detection element 702 is connected to the ground line 504-4 of the ground VSS via the resistor 703 for defining the operating point. The ground line 504-4 is the return destination of the constant current Is. The source terminal of the second read switch 705 is connected to the line connecting the other terminal of the temperature detection element 702 and the resistor 703. The drain terminal of the second read switch 705 is connected to the common wire 504-3 for reading the terminal voltage vb.

[0063] In segment seg0, selection signal hv0 is supplied to gate terminals of selection switch 701 and first read switch 704, and selection signal lv0 is supplied to gate terminal of second read switch 705. Selection switch 701 and first read switch 704 are turned on / off according to selection signal hv0. Second read switch 705 is turned on / off according to selection signal lv0.

[0064] Segments seg1 to seg511 also have the same connection structure as segment seg0. In segments seg1 to seg511, selection switches 701 and first read switches 704 are turned on / off according to selection signals hv1 to hv511, and second read switches 705 are turned on / off according to selection signals lv1 to lv511.

[0065] Next, we will describe the Figure 3 1. The operation of the temperature detection element in the printing element substrate 101 shown in FIG. 1 to output determination data.

[0066] Figure 8 1 is a timing chart for explaining the operation of the printing element substrate 101. Figure 8 As shown in FIG. 1 , during the period of block 1, the data input circuit 304 detects the selection information 1101 of the temperature detection element and outputs the transmission clock signal clk_s (1102) and the serial data d_s (1103). The data is transmitted to the temperature detection element circuit 306 and the inspection circuit 308. The selection information 1101 is taken into the shift register 501 of the temperature detection element circuit 306.

[0067] In the period of block 2, the selection information 1101 captured by the temperature detection element circuit 306 is latched according to the latch signal l_lt (1105), and the selection data a0 to a8 (1106) are output. In response to this, the decoder 503 outputs the selection signal lv (1108) of seg0 and the voltage-converted selection signal hv (1108). Figure 8 , reference numeral 1108 denotes the timing of both the selection signal lv and the selection signal hv.

[0068] On the other hand, although not Figure 8, but the selection data of the printing element corresponding to the temperature detection element is given to select the printing element. When the printing element of seg0 is selected, the pulse (1104) of the application signal he is supplied to the selected printing element, and the temperature waveform (1109) of the temperature detection element of seg0 is obtained. The inspection circuit 308 receives the temperature waveform, determines whether the ejection is normal, and holds the determination data. During this period, the selection information of the next temperature detection element is transmitted.

[0069] During the period of block 3, the held determination data (1111) is output to the data line of the serial data signal Do at the timing of the latch signal 1_1t, and is transmitted in synchronization with the transmission clock signal CLK2 (1110). The same process is repeated after block 3.

[0070] Next, the operating voltage range of the temperature detection element circuit 306 will be described. 9A to 9D 3 is a diagram for explaining the operating voltage range of the temperature detection element circuit 306 . Fig.9A 2 is a block diagram showing the configuration of a segment circuit 801 for a temperature detection element of 1 segment. Fig. 9B is a graph showing the relationship between the voltage of each section of the segment circuit 801 of the temperature detection element and the constant current Is. Fig. 9C 3 is a characteristic diagram showing a drop in the output voltage of the current source 307 . Fig.9D 3 is a characteristic diagram showing the on-resistance characteristics of the selection switch 701.

[0071] exist Fig.9A In the fragment circuit 801 shown in FIG. 8 , a selection signal lv having a voltage amplitude value of 3.3V is supplied to the gate terminals of the voltage conversion circuit 502 and the second read switch 705. The voltage conversion circuit 502 converts the selection signal lv into a selection signal hv having a voltage amplitude value of 5V. The selection signal hv is supplied to the gate terminals of the selection switch 701 and the first read switch 704. The selection switch 701 and the first read switch 704 are driven according to the selection signal hv, and the second read switch 705 is driven according to the selection signal lv. The fragment circuit 801 is constituted Figure 5 Each fragment of the fragment circuit 504 shown in .

[0072] The current source 307 operates using a power supply voltage VHT (5V). The current source 307 supplies a constant current Is to one terminal of the temperature detection element 702 via the selection switch 701. When the selection switch 701 is turned on, the constant current Is flows through the temperature detection element 702. When the first read switch 704 is turned on, a terminal voltage va of one terminal of the temperature detection element 702 is output. When the second read switch 705 is turned on, a terminal voltage vb of the other terminal of the temperature detection element 702 is output.

[0073] like Fig. 9B As shown in FIG. 1 , the drain voltage v1 of the selection switch 701, the voltage v2 (terminal voltage va) on one terminal side of the temperature detection element 702, and the voltage v3 (terminal voltage vb) on the other terminal side increase as the constant current Is increases. The voltage (v2 to v3) between the terminals of the temperature detection element 702 is the temperature information. Here, the current source 307 has Fig. 9C The output characteristics shown in FIG. 1 and a voltage drop of 0.9 V is generated for 2.7 mA (Δv represents the output voltage drop). The selection switch 701 has Fig.9D The on-resistance characteristics shown in (with respect to the range of 0 to 3 V of the voltage v2, the range of the on-resistance ron is 60Ω to 200Ω). The resistance value of the temperature detection element 702 is 1 kΩ, and the resistance value of the operating point resistor 703 is 100Ω.

[0074] According to the output characteristics of the current source 307, the maximum value of the constant current range is about 2.7 mA, and the voltage v2 becomes the maximum value of 3 V. On the other hand, the threshold voltage vth between the gate and the source of the first read switch 704 is 0.6 V. When the selection signal hv (= vg1) is 5 V, the read range A1 of the first read switch 704 becomes 4.4 V (= vg1-vth=5 V-0.6 V) or less. In this case, since the temperature detection element circuit 306 operates in the relationship of the read range A1>v2, the correct temperature information can be read.

[0075] On the other hand, the threshold voltage vth between the gate and the source of the second read switch 705 is 0.6V. When the selection signal lv (=vg2) is 3.3V, the reading range A2 of the second read switch 705 becomes 2.7V (=vg2-vth=3.3V-0.6V) or less. In this case, since the temperature detection element circuit 306 operates with the relationship of the reading range A2>v3, the correct temperature information can be read. Although the threshold voltage Vth of the first read switch 704 is slightly larger than the threshold voltage Vth of the second read switch 705, in order to simplify the description, the two threshold voltages Vth are expressed as the same value (0.6V).

[0076] (Comparison example)

[0077] Next, the operating voltage range of the temperature detection element circuit of the comparative example will be described. Fig. 10A and Fig. 10B is a diagram for explaining the operating voltage range of the temperature detection element circuit of the comparative example. Fig. 10A : is a block diagram showing a segment circuit and a voltage conversion circuit for a temperature detection element of one segment. Fig. 10BIt is a graph showing the relationship between the voltage of each part of the segment circuit and the constant current Is.

[0078] Fig. 10A The segment circuit shown in includes a selection switch 1201, a temperature detection element 702, a first read switch 1204, a second read switch 1205, and a resistor 703. The current source 307, the temperature detection element 702, and the resistor 703 are the same as those shown in Fig.9A The selection switch 1201, the first read switch 1204, and the second read switch 1205 are all made of NMOS transistors.

[0079] The drain terminal of the selection switch 1201 is connected to the current source 307, and the source terminal is connected to one terminal of the temperature detection element 702. The source terminal of the first read switch 1204 is connected to the wire connecting the source terminal of the selection switch 1201 and one terminal of the temperature detection element 702. The source terminal of the second read switch 1205 is connected to the wire connecting the other terminal of the temperature detection element 702 and the resistor 703.

[0080] A selection signal lv with a voltage amplitude value of 3.3V is supplied to the voltage conversion circuit 1202 and the gate terminals of the first read switch 1204 and the second read switch 1205. The voltage conversion circuit 1202 converts the selection signal lv into a selection signal hv with a voltage amplitude value of 5V. The selection signal hv is supplied to the gate terminal of the selection switch 1201. The selection switch 1201 is driven according to the selection signal hv, and the first read switch 1204 and the second read switch 1205 are driven according to the selection signal lv.

[0081] As Fig. 10B shown, the drain voltage v1 of the selection switch 1201, the voltage v2 (terminal voltage va) on one terminal side of the temperature detection element 702, and the voltage v3 (terminal voltage vb) on the other terminal side increase as the constant current Is increases. In the Fig. 10B graph, the conditions described in the description of the Fig. 9B graph are also used.

[0082] The maximum value of the constant current range of the current source 307 is approximately 2.7mA, at which time the voltage v2 becomes the maximum value of 3V. The threshold voltages vth between the gates and sources of the first read switch 1204 and the second read switch 1205 are both 0.6V. When the selection signal lv (=vg2) is 3.3V, the read range A becomes 2.7V (=vg2 - vth = 3.3V - 0.6V) or less. In this case, since the temperature detection element circuit operates in a relationship where the read range A < v2 range, the temperature information cannot be correctly read.

[0083] As described above, according to the printing element substrate 101 of the present disclosure, when the operating range of the current source 307 is expanded by increasing the power supply voltage, not only the selection switch 701 but also the first reading switch 704 is driven by using the selection signal hv boosted by the voltage conversion circuit 502. Therefore, the voltage drop of the selection switch 701 can be suppressed, and the input voltage range of the first reading switch 704 can be made to correspond to the operating voltage range of the temperature detection element 702 operating within the voltage range of the power supply voltage VHT. Therefore, the S / N ratio of the temperature detection signal (temperature information) can be increased, and the terminal voltage of the temperature detection element 702 can be accurately read according to the expanded temperature detection voltage range. Therefore, the judgment accuracy of the ejection failure can be improved.

[0084] In the printing element substrate 101 of this embodiment, the high breakdown voltage element is used for the selection switch 701 and the first read switch 704 on the high potential side, and the low breakdown voltage element can be used for the second read switch 705 on the low potential side. The element size of the low breakdown voltage element is smaller than the element size of the high breakdown voltage element. For example, in the case of a MOS transistor, in order to improve the breakdown voltage, there are measures in the vertical direction (depth direction) and measures in the horizontal direction (area direction). Basically, since it is necessary to reduce the electric field intensity, in the case of lateral countermeasures, it is necessary to set a layer with a low concentration and separate the distance between the source and the drain. Therefore, the area of ​​the high breakdown voltage MOS transistor is larger than the area of ​​the low breakdown voltage MOS transistor. Considering the area of ​​the entire read circuit, since the second read switch 705 on the low potential side can be miniaturized, the increase in area can be suppressed.

[0085] In the printing element substrate 101 of the present embodiment, the power supply voltage VHT and the power supply voltage VDD may be supplied in common to the Figure 4B The fragment circuit 802 of the printing element shown in FIG. Fig.9A A fragment circuit 801 of the temperature detection element is shown in FIG.

[0086] Fig.11 8 is a block diagram showing a configuration of a common power supply between a segment circuit 802 of a printing element and a segment circuit 801 of a temperature detection element. Fig.11As shown in , the power supply voltage VDD is supplied to the switch driving circuit 404 of the segment circuit 802 and the voltage conversion circuit 502 of the segment circuit 801 via a common power supply line. The power supply voltage VHT is supplied to the switch driving circuit 404 of the segment circuit 802, the voltage conversion circuit 502 of the segment circuit 801, and the current source 307 via a common power supply line. In other words, the power supply voltage of the switch driving circuit 404 and the power supply voltage of the voltage conversion circuit 502 are common. By sharing the power supply voltage VDD and the power supply voltage VHT between the segment circuit 802 of the printing element and the segment circuit 801 of the temperature detection element in this way, the circuit layout can be made efficient and space saving can be achieved.

[0087] <Second Embodiment>

[0088] Fig. 12A and Fig. 12B is a diagram for explaining the configuration of a printing element substrate according to the second embodiment of the present disclosure. Fig. 12A 2 is a block diagram showing the configuration of a segment circuit 901 for a temperature detection element of one segment. Fig. 12B is a block diagram showing the configuration of a temperature detection element circuit 903 applied to the segment circuit 901 .

[0089] Fig. 12A The fragment circuit 901 shown in FIG. Fig.9A The fragment circuit 901 shown in FIG. 1 is different in that it has a second read switch 902 instead of the second read switch 705. The second read switch 902 includes an NMOS transistor. The source terminal of the second read switch 902 is connected to a line connecting the other terminal of the temperature detection element 702 and the resistor 703. Although not shown in FIG. Fig. 12A , but the drain terminal of the second read switch 902 is connected to the common wire 504-3 (see Figure 7 ) is used to read the terminal voltage vb. The segment circuit 901 is composed of Figure 5 In this case, the decoder 503 supplies the selection signals lv0 to lv511 to the voltage conversion circuit 502 , but not to the segment circuit 504 .

[0090] exist Fig. 12AIn the fragment circuit 901 shown in FIG. 5 , the voltage conversion circuit 502 converts the small amplitude selection signal lv having a voltage amplitude value of 3.3V into a large amplitude selection signal hv having a voltage amplitude value of 5V. The selection signal hv is supplied to the gate terminals of the selection switch 701, the first read switch 704, and the second read switch 902. When the selection switch 701 is turned on, a constant current Is flows through the temperature detection element 702. When the first read switch 704 is turned on, a terminal voltage va of one terminal of the temperature detection element 702 is output. When the second read switch 902 is turned on, a terminal voltage vb of the other terminal of the temperature detection element 702 is output.

[0091] According to the printing element substrate of this embodiment, as in the first embodiment, the S / N ratio of the temperature detection signal (temperature information) can be increased, and the terminal voltage of the temperature detection element 702 can be accurately read.

[0092] Since a high breakdown voltage element is used for the second read switch 902, the element size is slightly larger than that in the first embodiment. However, since the selection signal hv can be supplied to the selection switch 701, the first read switch 704, and the second read switch 902 through a common wire, the wire space can be reduced. Therefore, the increase in element size and the reduction in wire space are offset, and the increase in the area of ​​the entire read circuit can be suppressed.

[0093] In the printing element substrate of this embodiment, it is also possible to use Fig. 12B The temperature detection element circuit 903 shown in FIG. The temperature detection element circuit 903 includes a shift register 501, a voltage conversion circuit 904, a decoder 905, and a temperature detection element segment circuit 907. The shift register 501 and Figure 5 The temperature detection element circuit 903 may be referred to as a temperature detection device. The voltage conversion circuit 904 and the decoder 905 may be referred to as a signal processing unit.

[0094] The voltage conversion circuit 904 operates when the power supply voltage VDD and the power supply voltage VHT are supplied, and converts an input signal having a small amplitude corresponding to the power supply voltage VDD into a signal having a large amplitude corresponding to the power supply voltage VHT. Here, the power supply voltage VDD is 3.3V and the power supply voltage VHT is 5V.

[0095] The voltage conversion circuit 904 receives the selection data a0 to a8 having a voltage amplitude value of 3.3V and outputs the selection data b0 to b8 having a voltage amplitude value of 5V.

[0096] The decoder 905 is composed of high breakdown voltage elements and operates by supplying a power supply voltage VHT. The decoder 905 receives selection data b0 to b8 and outputs selection signals hv0 to hv511 having a voltage amplitude value of 5V.

[0097] and Figure 5 Like the fragment circuit 504 shown in FIG. 1 , the fragment circuit 907 of the temperature detection element has 512 fragments, and each fragment includes Fig. 12A In the segment circuit 907, one segment is selected from 512 segments according to the selection signals hv0 to hv511, and a constant current Is is supplied to the temperature detection element 702 via the wire. At the same time, the terminal voltages va and vb at both ends of the temperature detection element 702 are output via the wire.

[0098] The temperature detection element circuit 903 can also increase the S / N ratio of the temperature detection signal (temperature information) and accurately read the terminal voltage of the temperature detection element 702. Since the decoder 905 needs to be composed of a high breakdown voltage element, the element size of the decoder 905 is slightly larger than the element size of the temperature detection element circuit 306. However, by arranging the voltage conversion circuit 904 in the previous stage of the decoder 905, the number of signal lines can be reduced, and the circuit scale of the voltage conversion circuit 904 can be reduced. Therefore, the increase in element size and the reduction in circuit size are offset, and the increase in the area of ​​the entire circuit can be suppressed.

[0099] <Third Embodiment>

[0100] Fig.13 is a diagram for explaining the configuration of a printing element substrate according to a third embodiment of the present disclosure. Fig.13 FIG. 1 shows a structure of a segment circuit 1001 for a temperature detection element of one segment. The segment circuit 1001 is configured by Fig.9A The fragment circuit 1001 is formed by removing the second read switch 705 from the configuration of the fragment circuit 901 shown in FIG. Figure 5 In this case, the decoder 503 supplies the selection signals lv0 to lv511 to the voltage conversion circuit 502 , but not to the segment circuit 504 .

[0101] In the segment circuit 1001, when the selection switch 701 is turned on, a constant current Is flows through the temperature detection element 702. When the first read switch 704 is turned on, a terminal voltage of one terminal (a terminal on a high potential side) of the temperature detection element 702 is output as temperature information.

[0102] Also, in the printing element substrate of the present embodiment, the S / N ratio of the temperature detection signal (temperature information) can be increased, and the terminal voltage of the temperature detection element 702 can be accurately read. Fig.9A Compared with the fragment circuit 901 shown in , the fragment circuit 1001 is affected by the wire resistance of VSS according to the fragment position, but by sufficiently reducing the wire resistance value, it is possible to obtain detection accuracy equivalent to that of the fragment circuit 901. In addition, since the circuit configuration of the fragment circuit 1001 is simpler than that of the fragment circuit 901, the circuit layout can be made efficient and space saving can be achieved.

[0103] In the printing element substrate of each of the above embodiments, the connection relationship between the drain terminal and the source terminal may be reversed for the selection switch, the first read switch, and the second read switch. In this case, in the above description, the terms "drain terminal" and "source terminal" are replaced with "source terminal" and "drain terminal", respectively.

[0104] A temperature detection device according to another embodiment of the present disclosure includes a temperature detection element, a current source for supplying a constant current to the temperature detection element, a first MOS transistor, and a second MOS transistor. In the first MOS transistor, one of the two terminals other than the gate terminal is connected to one end of the temperature detection element, the other terminal is connected to the current source, and the gate terminal is supplied with a selection signal. In the second MOS transistor, one of the two terminals other than the gate terminal is connected to a line connecting one end of the temperature detection element and one terminal of the first MOS transistor, and the gate terminal is supplied with a selection signal. In the first MOS transistor and the second MOS transistor, the two terminals other than the gate terminal are a drain terminal and a source terminal. Assume that the threshold voltage between the gate terminal and one terminal of the second MOS transistor is V1, and assume that the voltage applied to the gate terminal is V2. Here, one end of the temperature detection element is a terminal on the high potential side. For example, when one terminal is a drain terminal, the threshold voltage V1 is the threshold voltage between the gate and the drain. The voltage amplitude value of the selection signal is amplified so that a value obtained by subtracting the threshold voltage V1 from the supplied voltage V2 becomes greater than a value of a terminal voltage generated at one end of the temperature detection element when a constant current is supplied to the temperature detection element via the first MOS transistor. The voltage amplitude value of the selection signal may be a value of a power supply voltage for operating the current source.

[0105] In the temperature detection device of the present embodiment, when the operating range of the current source is expanded by increasing the power supply voltage, the input voltage range of the second MOS transistor can be made to correspond to the operating voltage range of the temperature detection element operating within the voltage range of the power supply voltage. In addition, the voltage drop of the first MOS transistor can be suppressed. Therefore, the S / N ratio of the temperature detection signal (temperature information) can be increased, and the terminal voltage of the temperature detection element can be accurately read.

[0106] According to the present disclosure, the S / N ratio of a temperature detection signal (temperature information) can be increased, and the terminal voltage of a temperature detection element can be accurately read.

[0107] <Other embodiments>

[0108] The (one or more) embodiments of the present invention may also be implemented by reading out and executing computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be more completely referred to as a "non-transitory computer-readable storage medium") to perform the functions of one or more of the above (one or more) embodiments and / or a system or device including one or more circuits (e.g., application specific integrated circuits (ASICs)) for performing the functions of one or more of the above (one or more) embodiments, and by a method performed by a computer of the system or device, for example, by reading out and executing computer executable instructions from a storage medium to perform the functions of one or more of the above (one or more) embodiments and / or controlling one or more circuits to perform the functions of one or more of the above (one or more) embodiments. The computer may include one or more processors (e.g., a central processing unit (CPU), a microprocessing unit (MPU)), and may include a network of separate computers or separate processors to read out and execute computer executable instructions. Computer executable instructions may be provided to the computer, for example, from a network or a storage medium. The storage medium may include, for example, a hard disk, a random access memory (RAM), a read-only memory (ROM), a storage device of a distributed computing system, an optical disk (such as a compact disk (CD), a digital versatile disk (DVD), or a Blu-ray disk (BD)) TM ), one or more of flash memory devices, memory cards, etc.

[0109] The embodiments of the present invention may also be implemented by providing software (program) for performing the functions of the above-described embodiments to a system or device via a network or various storage media, and a computer or a central processing unit (CPU) or a microprocessing unit (MPU) of the system or device reads and executes the program.

[0110] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A printing element substrate, comprising: a plurality of printing elements configured to generate thermal energy for ejecting a liquid; as well as a temperature detection element circuit including a plurality of temperature detection elements provided corresponding to each of the plurality of printing elements, and configured to read temperature information by selectively energizing one of the plurality of temperature detection elements, The temperature detection element circuit includes: a signal processing section configured to output a selection signal having a second voltage amplitude greater than the first voltage amplitude based on an input signal having a first voltage amplitude; A selection switch provided for each of the plurality of temperature detection elements and configured to select the temperature detection element; and a first reading switch provided for each of the plurality of temperature detection elements, configured to read a voltage of a terminal of one of the temperature detection elements selected by the selection switch, and wherein the selection switch and the first read switch are driven by using the selection signal, wherein the temperature detection element circuit is provided for each of the plurality of temperature detection elements and includes a second reading switch configured to read a voltage of another terminal of the temperature detection element selected by the selection switch, and The second read switch is driven by using an input signal having a first voltage amplitude. 2 . The printing element substrate according to claim 1 , wherein a withstand voltage of the second read switch is lower than a withstand voltage of the first read switch. 3 . The printing element substrate according to claim 1 , wherein a selection signal is supplied to the selection switch and the first reading switch via a common wire.

4. The printing element substrate according to claim 1, further comprising a current source configured to apply a constant current to the temperature detection element, wherein one end of the temperature detection element is electrically connected to the current source via the selection switch and is connected to the first read switch, and The second voltage amplitude is the same value as the power supply voltage used to operate the current source. 5 . The printing element substrate according to claim 4 , wherein the other end of the temperature detection element is connected to an electric wire as a return destination of the constant current via a resistor.

6. The printing element substrate according to claim 1, wherein the signal processing section comprises: a decoder configured to output a selection signal having a first voltage amplitude based on selection data for selecting the temperature detection element; as well as The voltage conversion circuit is configured to convert a selection signal having a first voltage amplitude output by the decoder into a selection signal having a second voltage amplitude.

7. The printing element substrate according to claim 1, wherein the signal processing section comprises: a voltage conversion circuit configured to convert selection data having a first voltage amplitude for selecting a temperature detection element into selection data having a second voltage amplitude; The decoder is configured to output a selection signal having a second voltage magnitude based on the selection data having a second voltage magnitude output by the voltage conversion circuit.

8. The printing element substrate according to claim 6, further comprising a printing element circuit configured to selectively energize one of the plurality of printing elements, The printing element circuit includes a switch for selecting a printing element and a switch driving circuit for turning the switch on and off, and The power supply voltage supplied to the switch driving circuit and the power supply voltage supplied to the voltage conversion circuit are shared.

9. The printing element substrate according to claim 1, wherein the temperature detection element is disposed in the vicinity of the printing element.

10. A temperature detection device, comprising: Temperature detection element; a current source configured to apply a constant current to the temperature sensing element; a first MOS transistor in which one of two terminals other than a gate terminal is connected to one of terminals of a temperature detection element and the other of the two terminals is connected to a current source, and a selection signal is supplied to the gate terminal; and a second MOS transistor in which one of two terminals other than a gate terminal is connected to a line connecting one of the terminals of the temperature detection element and the one terminal of the first MOS transistor, and a selection signal is supplied to the gate terminal, Wherein the voltage amplitude value of the selection signal is amplified so that a value obtained by subtracting a threshold voltage between the gate terminal and the one terminal of the second MOS transistor from a voltage applied to the gate terminal becomes greater than a value of a terminal voltage generated at one of the terminals of the temperature detection element when a constant current is applied to the temperature detection element via the first MOS transistor. 11 . The temperature detection device according to claim 10 , wherein the voltage amplitude value of the selection signal is a value of a power supply voltage for operating the current source.

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