Liquid dispensing head and liquid dispensing device

Abstract

This enables the appropriate supply of driving power to both the discharge drive element and the circulation drive element. [Solution] The invention includes a discharge module having a discharge drive element and a discharge heater electrically connectable to the discharge drive element, a circulation module arranged in pairs with the discharge module and having a circulation drive element and a circulation heater electrically connectable to the circulation drive element, and pulse width control means for differentiating between a discharge pulse width for controlling the discharge drive element to a conductive state and a circulation pulse width for controlling the circulation drive element to a conductive state.

Description

Technical Field

[0001] The present disclosure relates to a liquid ejection head and a liquid ejection device that perform ejection while circulating a liquid.

Background Art

[0002] Conventionally, among circulation-type liquid ejection devices that circulate a liquid (also referred to as ink), an ink in a circulation flow path communicating with a discharge port is circulated by a circulation driving element different from a discharge driving element that discharges the ink by a circulation driving element. Further, Patent Document 1 discloses a technique for selectively driving a discharge driving element and a circulation driving element.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the technique of Patent Document 1, even if the driving powers required for the discharge driving element and the circulation driving element are different, since each driving pulse width is the same, there may be a case where the driving power cannot be appropriately supplied to at least one of the discharge driving element and the circulation driving element.

Means for Solving the Problems

[0005] A liquid discharge head according to one aspect of the present disclosure is characterized by comprising: a discharge module having a discharge drive element and a discharge heater electrically connectable to the discharge drive element; a circulation module arranged in pair with the discharge module and having a circulation drive element and a circulation heater electrically connectable to the circulation drive element; and pulse width control means for differentiating between a discharge pulse width for controlling the discharge drive element to a conductive state and a circulation pulse width for controlling the circulation drive element to a conductive state. [Effects of the Invention]

[0006] According to this disclosure, it is possible to appropriately supply driving power to the discharge drive element and the circulation drive element, respectively. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows an example of the overall configuration of a liquid dispensing device according to the first embodiment. [Figure 2] This figure shows an example of the basic configuration of a liquid dispensing head. [Figure 3] Figure 2 shows an example of the circuit configuration of the ejection element substrate. [Figure 4] This figure shows an example of the circuit configuration of the control data supply circuit shown in Figure 3. [Figure 5] Figure 3 shows an example of the circuit configuration of a pulse width reduction circuit. [Figure 6] Figure 5 shows an example of pulse change due to the pulse width reduction circuit. [Figure 7] This figure shows an example of the circuit configuration of the delay circuit shown in Figure 5. [Figure 8] This figure shows other circuit configuration examples for the Delay circuit shown in Figure 5. [Figure 9] This is a plan view of the ejection element substrate α30. [Figure 10] This figure shows an example of the overall configuration of a liquid dispensing device according to the second embodiment. [Figure 11] Figure 10 shows an example of the circuit configuration of a pulse width extension circuit. [Figure 12] Figure 11 shows an example of pulse variation due to the pulse width extension circuit. [Figure 13] This figure shows an example of the overall configuration of a liquid dispensing device according to the third embodiment. [Figure 14] Figure 13 shows an example of the circuit configuration of a pulse width generation circuit. [Figure 15] Figure 14 shows an example of pulse variation caused by the pulse width generation circuit. [Modes for carrying out the invention]

[0008] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. Note that the following embodiments are not limiting to the scope of this disclosure, and not all combinations of features described in the following embodiments are essential to the solutions of this disclosure. The same reference numerals are used for identical components.

[0009] (overview) It has been pointed out that in liquid ejection heads, for example, volatile components in the ink may evaporate from the ejection port, potentially increasing the viscosity of the ink inside the port. This increased viscosity can alter the ink ejection speed, potentially leading to ejection failures that reduce the accuracy of ink placement. In particular, the increase in ink viscosity becomes more pronounced when the ink ejection pause time is long. As a result, solid components in the ink can adhere to the inside of the ejection port, increasing the ink flow resistance and making ink ejection failures more likely.

[0010] One known method to address this ink viscosity issue is to circulate fresh liquid through the discharge port in the liquid chamber. One method of circulating the liquid involves using a pump on the main body, separate from the fluid die that performs the discharge, to circulate the liquid within the head by creating a pressure difference. Alternatively, another method involves equipping the fluid die itself with a circulation element. Another method involves using a heating element to create a foaming mechanism within the fluid die itself to circulate the liquid.

[0011] Patent Document 1 discloses a configuration in which a fluid die is provided with a fluid energy generating element, and liquid is circulated through a discharge port row between both ends of the flow path extending so as to intersect the discharge port row.

[0012] However, the driving energies required due to the differences in the respective roles of the discharge heater and the circulation heater are different. Also, the required energy varies depending on the configuration of the flow path and the size of each heater. On the other hand, from the viewpoints of energy saving, durability, etc., it is desirable to apply appropriate drive pulses according to each configuration. In the circuit configuration of FIG. 5 in Patent Document 1, since signals with the same drive pulse width (hereinafter appropriately referred to as the pulse width) are input regardless of whether it is the discharge heater or the circulation heater, there is a possibility that the driving energy of either one will be insufficient or excessive. Also, when heat enable terminals are separately prepared so that the pulse width can be changed for each of the discharge heater and the circulation heater, the number of PADs increases, the signal lines outside the recording element substrate increase, and the cost of the liquid discharge head also increases.

[0013] Therefore, in the present disclosure, the discharge pulse width for controlling the discharge driving element to the conductive state and the circulation pulse width for controlling the circulation driving element to the conductive state are made different. Thereby, if the pulse width of the one for which power consumption is desired to be reduced is relatively shortened, the balance of the overall power consumption can be adjusted, so that the power shortage and surplus power of each of the discharge driving element and the circulation driving element can be eliminated.

[0014] (First Embodiment) <Liquid Discharge Device 50> FIG. 1 is a diagram showing an example of the overall configuration of a liquid discharge device 50 according to the first embodiment. FIG. 1(a) is a perspective view schematically showing a liquid discharge device 50 in which a main ink tank 2 as a liquid storage portion is provided outside a liquid discharge head 1. FIG. 1(b) is a perspective view schematically showing a liquid discharge device 50 in which an ink sub-tank 54 is provided directly above the liquid discharge head 1. First, the common part of FIGS. 1(a) and 1(b) will be described.

[0015] The liquid ejection device 50 comprises a liquid ejection head 1 and transport rollers 55, 56, 57, and 58. The liquid ejection head 1 is scannable in a direction X intersecting the transport direction Y of the ejection medium P. The liquid ejection head 1 is mounted on a carriage 60. The carriage 60 reciprocates along a guide axis 51 in the main scanning direction (also referred to as direction X). The transport rollers 55, 56, 57, and 58 transport the ejection medium P in a sub-scanning direction (also referred to as transport direction Y) that intersects (orthogonal in this embodiment) the main scanning direction. That is, the liquid ejection device 50 constitutes a serial-type inkjet ejection device that ejects an image by scanning the liquid ejection head 1 in direction X and ejecting liquid from the liquid ejection head 1 onto the ejection medium P being transported in the transport direction Y. Note that the application of this disclosure is not limited to serial-type inkjet ejection devices. This disclosure is also applicable to page-wide inkjet ejection devices that use a line head (page-wide head) that is long in the page width direction of the ejection medium P, and eject images by ejecting liquid onto the ejection medium P being transported in the transport direction Y. In Figures 1(a) and 1(b), direction Z indicates the vertical direction. That is, direction Z is the direction that intersects (orthogonal in this embodiment) the XY plane specified by direction X and transport direction Y.

[0016] The liquid ejection head 1 is capable of ejecting four types of ink: black (K), cyan (C), magenta (M), and yellow (Y). The liquid ejection head 1 can eject a full-color image using these four types of ink. However, the inks that can be ejected from the liquid ejection head 1 are not limited to the above four types. For example, this disclosure is also applicable to a liquid ejection head 1 for ejecting other types of ink, such as spot color inks. In other words, the type and number of inks ejected from the liquid ejection head 1 are not limited.

[0017] Next, we will explain the differences between Figure 1(a) and Figure 1(b). In Figure 1(a), an ink sub-tank 54 is mounted on the liquid ejection head 1. Four ink supply tubes (liquid passages) 59 are attached to the ink sub-tank 54. The liquid ejection device 50 also includes an ink tank 2 and an external pump 21. The ink tank 2 stores ink. The ink stored in the ink tank 2 is supplied to the ink sub-tank 54 via the four ink supply tubes 59 by the driving force of the external pump 21. On the other hand, in Figure 1(b), the ink sub-tank 54 is located directly above the liquid ejection head 1. In Figure 1(b), the difference from Figure 1(a) is that the ink tank 2 is not located outside the liquid ejection head 1, so the four ink supply tubes 59 are not attached, and the external pump 21 is not provided. In both Figure 1(a) and Figure 1(b), the liquid discharge head 1 may be integrally provided with the ink sub-tank 54 and configured to be removable from or attachable to the carriage 60. Alternatively, the ink sub-tank 54 may be integrally provided with the carriage 60, and only the ink sub-tank 54 may be configured to be removable from or attachable. In the following description, the configuration shown in Figure 1(a) will be used.

[0018] <Liquid dispensing head 1> Figure 2 shows an example of the basic configuration of the liquid ejection head 1 shown in Figure 1. Figure 2(a) is an exploded perspective view of the liquid ejection head 1 shown in Figure 1. Figures 2(b), 2(c), and 2(d) are overall views of the ejection element substrate α0 shown in Figure 2(a). The liquid ejection head 1 comprises a housing section 53, an ink sub-tank 54, an electrical contact substrate 61, and an ejection element unit 100. The ink sub-tank 54 is housed in the housing section 53. The ejection element unit 100 is located at the bottom of the housing section 53. One side of the housing section 53 is provided with four joints 53a, each connected to one of four ink supply tubes 59 corresponding to four types of ink. In other words, a separate ink supply path is provided for each type of ink. On the side opposite to the side with the four joints 53a, the electrical contact substrate 61 is fixed. The electrical contact substrate 61 is electrically connected to the electrical connection section of the carriage 60 when the liquid ejection head 1 is mounted on the carriage 60. This connection allows the electrical contact board 61 to receive electrical signals from the liquid dispensing device body. The electrical signals received by the electrical contact board 61 are transmitted to the dispensing element board α0 via the electrical wiring member 501.

[0019] The ejection element unit 100 comprises a first support member 504, a second support member 503, an ejection element substrate α0, and an electrical wiring member 501. The first support member 504 is provided with an ink supply port and an ink recovery port. The second support member 503 is provided with an opening 503a. The ejection element substrate α0 is adhesively fixed to the first support member 504. The first support member 504 is adhesively fixed to the second support member 503. The second support member 503 holds the electrical wiring member 501 so that it is electrically connected to the ejection element substrate α0. The electrical wiring member 501 applies an electrical signal to eject ink and an electrical signal to circulate ink to the ejection element substrate α0. Details of the electrical signal to eject ink and the electrical signal to circulate ink will be described later.

[0020] Figure 2(b) shows an example where one ejection element substrate α0 is configured for every four colors. The four colors are, for example, black, cyan, magenta, and yellow, and each color is in a separate column. Each column is configured along the transport direction Y and spaced apart along the direction X. Multiple ejection ports in each column are spaced equally along the Y direction. Alternatively, the ejection ports in each column may be arranged in a single row along the Y direction without spacing in the X direction. Alternatively, black may be arranged in two columns, resulting in a total of five columns for the four colors. Figure 2(c) shows an example where one ejection element substrate α0 is configured for every two colors. Two ejection element substrates α0 may be mounted on one liquid ejection head 1. Alternatively, two liquid ejection heads 1, each with one ejection element substrate α0 mounted, may be prepared. Figure 2(d) shows an example where one ejection element substrate α0 is configured for every one color. Four ejection element substrates α0 may be mounted on one liquid ejection head 1. Alternatively, four liquid ejection heads 1, each mounted on a single ejection element substrate α0, may be prepared. Note that, as shown in Figures 2(c) and 2(d), if the ejection element substrate α0 is divided into multiple parts, they do not all need to be the same length. Furthermore, various combinations of other colors are possible for the ejection element substrate α0, and the same applies when the total number of colors exceeds four. The details of the electrical signals for ejecting ink and the electrical signals for circulating ink will be explained below, referring to various use cases such as circuit configurations.

[0021] (Discharge element substrate α0) Figure 3 shows an example of the circuit configuration of the ejection element substrate α0 in Figure 2. Figure 4 shows an example of the circuit configuration of the control data supply circuit α3 in Figure 3. Figure 4(a) is a functional block diagram of the circuit configuration of the control data supply circuit α3. Figure 4(b) shows the circuit configuration of the circulating group control circuit α12 in Figure 4(a). Figure 5 shows an example of the circuit configuration of the pulse width reduction circuit γ1 in Figure 3. Figure 6 shows an example of pulse change due to the pulse width reduction circuit γ1 in Figure 5. Various signals are supplied to the ejection element substrate α0 from the main substrate β0. The main substrate β0 comprises a controller β1 and a power supply circuit β2. The controller β1 is mainly composed of ROM, RAM, and CPU, and controls the liquid ejection head 1 by supplying various electrical signals to the ejection element substrate α0. The controller β1 supplies the heat enable signal HE, latch signal LT, data signal DATA, and clock signal CLK to the ejection element substrate α0. Details of each signal will be described later. Furthermore, the power supply circuit β2 applies the power supply voltage VH to the ejection element substrate α0. The power supply circuit β2 and the ejection element substrate α0 are connected via GNDH. GNDH functions as the ground potential.

[0022] (Wiring Overview) The ejection element substrate α0 in Figure 3 comprises multiple ejection modules α1, multiple circulation modules α2, a control data supply circuit α3, and a pulse width reduction circuit γ1. The circulation modules α2 are arranged in pairs with the ejection modules α1. Therefore, the number of circulation modules α2 is the same as the number of ejection modules α1. Between the multiple ejection modules α1 and the control data supply circuit α3, the ejection group selection signal wiring α6, the shared time division selection signal wiring α8, and the ejection heat enable signal tHE transmission wiring are connected. Between the multiple circulation modules α2 and the control data supply circuit α3, the circulation group selection signal wiring α7, the shared time division selection signal wiring α8, and the circulation heat enable signal pHE transmission wiring are connected.

[0023] Here, the discharge heat enable signal tHE is the same heat enable signal HE that is transmitted directly. On the other hand, the circulation heat enable signal pHE is the same heat enable signal HE that is transmitted via the pulse width reduction circuit γ1. The pulse width reduction circuit γ1, as will be described in detail later, is a circuit that reduces the input pulse width and outputs it. Therefore, the pulse width of the circulation heat enable signal pHE is shorter than that of the discharge heat enable signal tHE. In addition, the shared time-division selection signal wiring α8 is shared between the discharge module α1 and the circulation module α2, which contributes to reducing the amount of serial data transferred and the layout area of ​​the signal wiring within the discharge element board α0, as will be described later.

[0024] (Discharge module α1) The ejection module α1 in Figure 3 includes an ejection heater RhA, an ejection drive element MD1, and an ejection logic circuit AND1. The ejection heater RhA is composed of, for example, an electrothermal conversion element. A voltage from the power supply voltage VH is applied to the ejection heater RhA, and if the ejection drive element MD1 is in a conductive state, current flows through the ejection heater RhA. The ejection drive element MD1 is composed of, for example, a MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor). Note that the ejection drive element MD1 may be composed of something other than a MOSFET. For example, the ejection drive element MD1 may be composed of a bipolar transistor. Alternatively, the ejection drive element MD1 may be composed of an IGBT (Insulated Gate Bipolar Transistor). The ejection logic circuit AND1 selectively drives the ejection drive element MD1. The ejection heat enable signal tHE, the ejection group selection signal, and the shared time division selection signal are input to the input side of the ejection logic circuit AND1. The discharge heat enable signal tHE is a signal that is directly transferred from the heat enable signal HE transmitted from the controller β1. The discharge heat enable signal tHE controls the current pulse width of the discharge drive element MD1, that is, the time for which the drain-source of the discharge drive element MD1 is conductive and current continues to flow between the drain-source of the discharge drive element MD1. The discharge heat enable signal tHE is a signal for adjusting the current pulse width so that more desired thermal energy can be generated, taking into account various manufacturing variations. Examples of various manufacturing variations include manufacturing variations in the resistance value of the discharge heater RhA mounted on the discharge element substrate α0, and manufacturing variations in the power supply circuit β2. Other examples of various manufacturing variations include the voltage drop in the power supply wiring when multiple heaters, such as the discharge heater RhA and the circulation heater RhB, are driven simultaneously. The heaters to be driven simultaneously here are the discharge heater RhA and the circulation heater RhB, which is located in a position not paired with the discharge heater RhA. The heat enable signal HE can be transmitted from the controller β1 via an external input terminal (not shown) provided on the discharge element substrate α0.The ejection group selection signal is supplied from the ejection group selection signal wiring α6. The ejection time division selection signal is supplied from the shared time division selection signal wiring α8. The output side of the ejection logic circuit AND1 is connected to the gate of the ejection drive element MD1. Therefore, if all signals input from the input side of the ejection logic circuit AND1 are 1, a voltage is applied to the gate of the ejection drive element MD1, and the drain-source of the ejection drive element MD1 becomes conductive. When the drain-source of the ejection drive element MD1 is conductive, current flows to the ejection heater RhA, and heat is generated in the ejection heater RhA. This series of operations makes it possible for the ink to foam before being ejected and ejected onto the ejection medium P. Although an example of the ejection heater RhA being composed of an electrothermal conversion element has been described, it is not limited to this. For example, the ejection heater RhA may be composed of a piezoelectric element.

[0025] (Circulation module α2) The circulating module α2 in Figure 3 includes a circulating heater RhB, a circulating drive element MD2, and a circulating logic circuit AND2. The circulating heater RhB is composed of, for example, an electrothermal conversion element. A voltage from the power supply voltage VH is applied to the circulating heater RhB, and if the circulating drive element MD2 is in a conductive state, current flows through the circulating heater RhB. The circulating drive element MD2 is composed of, for example, a MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor). Note that the circulating drive element MD2 may be composed of something other than a MOSFET. For example, the circulating drive element MD2 may be composed of a bipolar transistor. Alternatively, the circulating drive element MD2 may be composed of an IGBT (Insulated Gate Bipolar Transistor). The circulating logic circuit AND2 selectively drives the circulating drive element MD2. The input side of the circulating logic circuit AND2 receives the circulating heat enable signal pHE, the circulating group selection signal, and the shared time division selection signal. The circulating heat enable signal pHE is transmitted from controller β1 via pulse width reduction circuit γ1. Details of the pulse width reduction circuit γ1 will be described later. The circulating heat enable signal pHE controls the current pulse width of the circulating drive element MD2, that is, the time for which the drain-source of the circulating drive element MD2 is conductive and current continues to flow between the drain-source of the circulating drive element MD2. The circulating heat enable signal pHE is a signal for adjusting the current pulse width so that more desired thermal energy can be generated, taking into account various manufacturing variations. Examples of various manufacturing variations include manufacturing variations in the resistance value of the circulating heater RhB mounted on the discharge element substrate α0, and manufacturing variations in the power supply circuit β2. Other examples of various manufacturing variations include the voltage drop in the power supply wiring when multiple heaters, such as the circulating heater RhB and the discharge heater RhA, are driven simultaneously. The circulating heat enable signal pHE can be transmitted from controller β1 via an external input terminal (not shown) provided on the discharge element substrate α0. The group selection signal for the cycle is supplied from the group selection signal wiring α7.The output side of the circulating logic circuit AND2 is connected to the gate of the circulating drive element MD2. Therefore, if all signals input from the input side of the circulating logic circuit AND2 are 1, a voltage is applied to the gate of the circulating drive element MD2, and the drain-source of the circulating drive element MD2 becomes conductive. When the drain-source of the circulating drive element MD2 is conductive, current flows through the circulating heater RhB, generating heat in the circulating heater RhB. This series of operations allows ink bubbles to grow and a circulating flow to be generated in the ink circulation channel. Although an example of the circulating heater RhB being composed of an electrothermal conversion element has been described, it is not limited to this. For example, the circulating heater RhB may be composed of a piezoelectric element.

[0026] (Control data supply circuit α3) The control data supply circuit α3 in Figure 4 comprises shift registers α20a and α20b, latch circuits α21a and α21b, decoder circuit α22, and a circulating group control circuit α12. The control data supply circuit α3 is also provided with an external input terminal. The control data supply circuit α3 receives a clock signal CLK, a data signal DATA, and a latch signal LT from controller β1 via the external input terminal. The clock signal CLK is used when serially transferring the data signal DATA to shift registers α20a and α20b. The data signal DATA includes selection information for the output module α1 and selection information for the circulating module α2. The latch signal LT acquires and holds the information stored in shift registers α20a and α20b at each latch period. Details of the decoder circuit α22 and the circulating group control circuit α12 will be described later.

[0027] (Pulse width reduction circuit γ1) As shown in Figure 5, the pulse width reduction circuit γ1 comprises a delay circuit and an AND circuit. Figure 6(a) shows the pulse shape in Figure 5(a). Figure 6(b) shows the pulse shape in Figure 5(b). Figure 6(c) shows the pulse shape in Figure 5(c). Here, we assume that the pulse width of the heat enable signal HE is 0.8 μs. Also, when the heat enable signal HE is input to the pulse width reduction circuit γ1, it branches before being input to the delay circuit. One of the branched signals is input to the delay circuit, and the other branched signal bypasses the delay circuit and is input to the AND circuit. The AND circuit receives the signal that bypasses the delay circuit and the signal output from the delay circuit. Compared to Figure 6(a), in Figure 6(b), the heat enable signal HE passes through the delay circuit, so the rising edge is delayed by, for example, 0.2 μs. Therefore, the pulse width of the signal output from the AND circuit is 0.6 μs. In other words, the pulse width of the discharge heat enable signal tHE remains at 0.8 μs, while the pulse width of the circulation heat enable signal pHE becomes 0.6 μs. Therefore, if the delay amount of the delay circuit is 0.2 μs, the difference between the discharge heat enable signal tHE and the circulation heat enable signal pHE becomes 0.2 μs. In other words, if the delay amount of the delay circuit is 0.2 μs or less, the difference between the pulse width of the discharge heat enable signal tHE and the pulse width of the circulation heat enable signal pHE becomes 0.2 μs or less. Therefore, the difference between the pulse width of the discharge heat enable signal tHE and the pulse width of the circulation heat enable signal pHE can be set to be less than or equal to the delay amount of the delay circuit. Thus, the difference between the pulse width of the discharge heat enable signal tHE and the pulse width of the circulation heat enable signal pHE can be managed to be less than or equal to the delay amount of the delay circuit, which is 0.2 μs.

[0028] (Delay circuit) Figure 7 shows an example of the circuit configuration of the Delay circuit in Figure 5. As shown in Figure 7, the Delay circuit comprises multiple inverter circuits. Each inverter circuit is connected in series. Assume the delay amount of one inverter circuit is 10 ns. Under this assumption, if 20 of these inverter circuits are connected in series, the pulse width of the signal will be delayed by 0.2 μs compared to the original pulse width. Note that the number of connected inverter circuits is not limited to 20. For example, assuming the delay amount of one inverter circuit is 20 ns, 10 may be connected in series. Alternatively, the number of connected inverter circuits may be controlled separately within the ejection element substrate α0 by an external signal, allowing the desired number of connections to be specified for each drive, and the amount of pulse width reduction to be adjustable. Alternatively, the Delay circuit may be implemented using an FPGA (Field Programmable Gate Array). Alternatively, instead of connecting multiple inverter circuits in series, the signal delay may be achieved using an RC circuit. Figure 8 shows another example of the circuit configuration of the Delay circuit in Figure 5. As shown in Figure 8, the pulse width of a signal may be delayed by an RC circuit in which a resistor R and a capacitor C are connected in series. Specifically, this is a circuit in which the resistor R is connected between the input terminal and the output terminal, and the capacitor C is connected between the output terminal and GND. The delay time is determined by the product of the resistor R and the capacitor C, so it can be arbitrarily designed by multiplying the resistor R by the capacitor C. For example, by using a 10kΩ resistor R and a 20pF capacitor C, the combined resistance of the RC circuit becomes 0.2μs. Therefore, it is possible to delay the pulse width by approximately 0.2μs compared to the original pulse width. Accordingly, it is possible to prepare multiple types of resistors R and capacitors C in advance within the delay circuit, and select the desired resistor R and capacitor C using an external signal, thereby adjusting the delay amount and shortening amount of the pulse width for each drive.

[0029] From the above explanation, the pulse width of the circulating heat enable signal pHE, which passes through the pulse width reduction circuit γ1, is shorter than that of the discharge heat enable signal tHE, which does not pass through the pulse width reduction circuit γ1, making it possible to have different pulse widths. In this embodiment, an example in which the pulse width of the circulating heat enable signal pHE is shortened by the pulse width reduction circuit γ1 has been described, but it is not limited to this. The wiring configuration may also include the discharge heat enable signal tHE passing through the pulse width reduction circuit γ1, while the circulating heat enable signal pHE does not pass through the pulse width reduction circuit γ1. Furthermore, as will be explained in detail in the second embodiment, a pulse width extension circuit γ2 that extends the pulse width may be incorporated into the wiring configuration. For example, the pulse width of the discharge heat enable signal tHE may be extended by the pulse width extension circuit. In other words, if the pulse width of the pulse for which power consumption is to be reduced is relatively shortened, the balance of overall power consumption on the discharge element substrate α0 can be adjusted, thereby resolving power shortages and surpluses of the discharge drive element and the circulating drive element, respectively.

[0030] (Drive control of the discharge heater RhA) Returning to Figure 3, we will now describe the drive control of the ejection heaters RhA based on the ejection heater array α9 in Figure 3. The ejection heater array α9 consists of m groups. Each group contains n ejection heaters RhA. The ejection heaters RhA are positioned directly below the ink ejection port. When one group is selected, each of the n ejection heaters RhA within that group is executed sequentially in a time-division multiplexing manner. The ejection heater array is arranged in a 1-inch length at an array density of 600 dpi, and we will now describe the drive control of (n=16) × (m=40 groups) of ejection heaters RhA.

[0031] (Time-division control within a single group) As described above, each ejection module α1 contains an ejection heater RhA. Furthermore, one group contains n ejection heaters RhA. Therefore, one group contains n ejection modules α1. Since we are assuming n=16, the 16 ejection modules α1 are time-division driven by a shared time-division selection signal. Time-division driving is a control method that divides the time of a certain ejection cycle into n=16 time units, and sequentially selects one ejection module α1 for each divided time unit. Here, within the same group, multiple ejection modules α1 are never selected simultaneously. All ejection modules α1 included in the same group are always selected exactly once within one ejection cycle. In this type of time-division driving, only one of the shared time-division selection signal wires α8 is selected. Therefore, by including the decoder circuit α22 in the control data supply circuit 31, the amount of data transferred serially from the main board β0 can be further reduced.

[0032] (Decoder circuit α22; time-division control) Returning to Figure 4, the decoder circuit α22 in Figure 4 is a circuit that expands the number of bits in the output data to 2 to the power of q, where q is the number of bits in the input data. Specifically, if 4 bits of input data are input to the decoder circuit α22, the decoder circuit α22 converts the 4 bits of input data into 2 to the power of 4 = 16 bits of output data. At this time, the output data of the decoder circuit 15 is output as information in which only 1 bit of the 16 bits is valid. This enables time-division driving. Here, the shared time-division selection signal wiring α8 output from the decoder circuit α22 should be used entirely as output time-division selection signals, unless there is a special application, as this is more efficient in terms of using input data. Note that as the amount of data in serial transfer increases, faster serial transfer is required. Therefore, it is preferable to reduce the amount of data as much as possible, as this will increase the cost and size of the signal transmission circuit, signal reception circuit, and transmission line on the main board β0 and the output element board α0.

[0033] (Group selection control) To select and drive one of the m groups, an m-bit ejection group selection signal is output from the control data supply circuit α3. When selecting one of the m groups, it is possible to simultaneously select n ejection modules α1 included in that group. Information equivalent to the number of groups, m bits, is serially transferred from the main board β0. As described above, the ejection module α1 is selected and controlled so that current flows to the corresponding ejection heater RhA when the heat enable signal HE, the ejection group selection signal, and the ejection time division selection signal are input to the ejection logic circuit AND1. In this embodiment, an example is described assuming n=16 and m=40, but it is not limited to these. For example, n=8 and m=80 may also be used. Alternatively, for example, a different nozzle length n=32 and m=40 may be used. However, since n is the time division number, it is preferable that n be a value expressed as a power of 2 (n=2, 4, 8, 16, 32...) in order to use the output signal of the decoder circuit 15 as the selection signal.

[0034] (Drive control of circulation module α2) Returning to Figure 3, we will now describe the drive control of the circulating heater RhB based on the circulating heater array α10 in Figure 3. The circulating heater array α10, like the discharge heater array α9, consists of m groups. Each group contains n circulating heaters RhB, similar to the discharge heater array α9. The circulating heater RhB is positioned in close proximity to the discharge heater RhA in pairs. When one group is selected, each of the n circulating heaters RhB within that group is executed sequentially in a time-division multiplexer. We will now describe the drive control of the circulating heater RhB for (n=16) × (m=40 groups).

[0035] (Time-division control within a single group) As described above, the circulating heater RhB is included in each circulating module α2. Furthermore, one group contains n circulating heaters RhB. Therefore, one group contains n circulating modules α2. Also, since we assume n=16, the 16 circulating modules α2 are time-division driven by a shared time-division selection signal with a time division ratio. In this embodiment, the time division ratio of the circulating module α2 is the same as the time division ratio of the discharge module 11, n=16.

[0036] (Group selection control) To select and drive one of the m groups, an m-bit cyclic group selection signal is output from the control data supply circuit α3. When selecting one of the m groups, it is possible to simultaneously select n cyclic modules α2 included in that group. Information equivalent to the number of groups, m bits, is serially transferred from the main board β0. As described above, the cyclic module α2 is selected and controlled so that current flows to the corresponding cyclic heater RhB when the heat enable signal HE, the cyclic group selection signal, and the shared time division selection signal are input to the cyclic logic circuit AND2. However, the cyclic group selection signal is transferred from the cyclic group control circuit α12 in Figure 4 via the cyclic group selection signal wiring α7. The cyclic group control circuit α12 in Figure 4 is included in the control data supply circuit α3.

[0037] (Circulation group control circuit α12) The circulating group control circuit α12 in Figure 4 includes an AND gate and a NOT gate. The NOT gate outputs a signal that is the logical inversion of the ejection group selection signal obtained from the ejection group selection signal wiring α6 (hereinafter also referred to as the logical inversion signal). The AND gate receives the logical inversion signal and the circulating flag signal α13 as inputs. The circulating flag signal α13 is included in the data signal DATA that is serially transferred from the controller β1. The circulating flag signal α13 functions as a flag to set the circulating group selection signal output via the circulating group selection signal wiring α7 to enabled or disabled. In normal ejection operation where ink circulation is not required, the circulating flag signal α13 should be set to 0 to prohibit the selection of the circulating module α2. In other words, the circulating group control circuit α12 generates the circulating group selection signal according to the selection information of the ejection group selection signal and the circulating flag signal α13. Therefore, when the ejection module α1 is selected, the circulating module α2 is not selected. On the other hand, even if the discharge module α1 is not selected, if the circulation flag signal α13 is 0, the circulation group selection signal is ineffective, and the circulation module α2 will not be selected. That is, if the discharge module α1 is not selected and the circulation flag signal α13 is 1, the circulation group selection signal is effective, and the circulation module α2 will be selected. Note that while time-division selection is not performed, neither the discharge module 11 nor the circulation module 12 will be selected.

[0038] In this embodiment, the discharge module 11 and the circulation module 12 are each connected to a common power supply voltage VH (e.g., 24V) and a common ground potential GNDH. However, if it is desired to further mitigate fluctuations in discharge energy due to voltage drops when driving the discharge heater RhA and the circulation heater RhB, the following measures can be taken. Specifically, separate power supply voltage and ground potential supply wiring and external connection terminals may be provided for the discharge module 11 and the circulation module 12 within the discharge element board 101. In other words, they may be supplied individually from the power supply circuit 203 mounted on the main board 201.

[0039] Generally, since drive elements operate at a higher voltage than logic circuits, a substrate is used in which high-voltage drive elements and normal drive elements coexist. In this embodiment, the ejection drive element MD1 and the circulation drive element MD2 may be composed of high-voltage MOS transistors, specifically DMOS transistors (Double-diffused MOSFETs). The ejection logic circuit AND1, the circulation logic circuit AND2, the circulation group selection circuit 16, and other logic circuits such as shift registers 13a, 13b, 13c, latch circuits 14a, 14b, 14c, and decoder circuit 15 may be composed of low-voltage MOS transistors.

[0040] (Circuit area) Next, we will explain the differences due to the circuit configuration. The drive current of the circulating heater RhB generates thermal energy to circulate the ink in the individual channels. When the drive current of the circulating heater RhB is smaller than the drive current of the ejection heater RhA that ejects to the ejection medium, the current driving capability of the DMOS transistor can be small. Therefore, since it is not necessary to make the area of ​​the circulating drive element MD2 larger than the area of ​​the ejection drive element MD1, a configuration in which the area of ​​the circulating drive element MD2 is smaller than the area of ​​the ejection drive element MD1 is more preferable.

[0041] (Example 1 of circuit layout) Figure 9 is a plan view of the ejection element substrate α30. In one example in Figure 9, two systems of mechanisms for selective control are arranged from the control data supply circuit α3 to the ejection heater row α9 and the circulation heater row α10, with point symmetry based on the center of the ejection element substrate α30. In Figure 9, in the transport direction Y, three rows of ink supply port arrays α14 are arranged with spacing along the direction X. Between each ink supply port array α14, one row each of the ejection heater row α9 and the circulation heater row α10 is arranged along the transport direction Y. Of the three rows of ink supply port arrays α14, the left region of the left ink supply port array α14 and the right region of the right ink supply port array α14 are arranged as follows: ejection drive element MD1, circulation drive element MD2, ejection logic circuit AND1, circulation logic circuit AND2, ejection group selection signal wiring α6, circulation group selection signal wiring α7, and shared time division selection signal wiring α8. Furthermore, the left region of the left ink supply port array α14 and the right region of the right ink supply port array α14 are further equipped with transmission wiring for the ejection heat enable signal tHE and transmission wiring for the circulation heat enable signal pHE, respectively.

[0042] External connection terminals are arranged along the X direction at two locations, above and below the substrate edge in the transport direction Y of the ejection element substrate α30. A control data supply circuit α3 is located in the area between the external connection terminals and the ink supply port array α14. Since the area between the external connection terminals and the ink supply port array α14 is located at two locations, above and below, in the transport direction Y, the control data supply circuit α3 and the pulse width reduction circuit γ1 are also located at two locations, above and below, in the transport direction Y.

[0043] As shown in Figure 9, since the ejection element substrate α30 is configured to be positioned in the transport direction Y, it is possible to reduce the substrate dimensions in the direction X of the ejection element substrate α30. Although not shown in the figure, if the arrangement configuration of the ejection element substrate α30 is considered as one unit, it is also possible to arrange multiple ejection element substrates α30 in the direction X to provide multiple ink types within a single ejection element substrate α30.

[0044] Furthermore, as is common to other embodiments, each element within the ejection element substrate α30 can be integrally and finely formed using semiconductor process technology. The pulse width reduction circuit γ1 can also be formed using semiconductor process technology. The pulse width reduction circuit γ1 has a simple configuration consisting of a delay circuit and an AND circuit, making it easy to miniaturize. Therefore, the pulse width reduction circuit γ1 can also be easily placed within the ejection element substrate α30. Consequently, by suppressing an increase in the size of the ejection element substrate α30, the manufacturing cost of the ejection element substrate α30 can be reduced.

[0045] Furthermore, compared to the case where separate external terminals for heat enable signal input are provided to allow for different pulse widths for the discharge heater RhA and the circulation heater RhB, it is possible to reduce the number of PADs. In addition, since the wiring of the heat enable signal HE outside the discharge element substrate α30 can be reduced, the cost increase of the liquid discharge head 1 can be suppressed. Moreover, by reducing the wiring of the heat enable signal HE outside the discharge element substrate α30, signal crosstalk can be suppressed.

[0046] (Second embodiment) Figure 10 shows an example of the overall configuration of a liquid dispensing device according to the second embodiment. The second embodiment differs from the first embodiment in that a pulse width extension circuit γ2 is provided instead of a pulse width shortening circuit γ1. The differences from the first embodiment will be explained below, and the explanation of the same configuration and functions as the first embodiment will be omitted.

[0047] (Pulse width extension circuit γ2) Figure 11 shows an example of the circuit configuration of the pulse width extension circuit γ2 shown in Figure 10. Figure 12 shows an example of pulse change due to the pulse width extension circuit in Figure 11. As shown in Figure 11, the pulse width extension circuit γ2 includes a delay circuit and an OR circuit. Figure 12(a) shows the pulse shape in Figure 11(a). Figure 12(b) shows the pulse shape in Figure 11(b). Figure 12(c) shows the pulse shape in Figure 11(c). Here, we assume that the pulse width of the heat enable signal HE is 0.8 μs. Also, when the heat enable signal HE is input to the pulse width extension circuit γ2, it branches before being input to the delay circuit. One of the branched signals is input to the delay circuit, and the other branched signal bypasses the delay circuit and is input to the OR circuit. The OR circuit receives the signal that bypasses the delay circuit and the signal output from the delay circuit. Compared to Figure 12(a), in Figure 12(b), the heat enable signal HE passes through the delay circuit, so the rising edge is delayed by, for example, 0.2 μs. Therefore, the pulse width of the signal output from the OR circuit becomes 1.0 μs. In other words, the pulse width of the discharge heat enable signal tHE becomes 1.0 μs, while the pulse width of the circulation heat enable signal pHE remains at 0.8 μs.

[0048] (Delay circuit) The delay circuit in Figure 11, like that in Figure 7 of the first embodiment, comprises multiple inverter circuits. Assuming a pulse width of 0.8 μs for the heat enable signal HE and a delay of 10 ns for one inverter circuit, if 20 of these inverter circuits are connected in series, the signal pulse width will be delayed by 0.2 μs compared to the original pulse width. That is, the signal at location 11(b) in Figure 11 is delayed by 0.2 μs compared to the signal at location 11(a). Therefore, the pulse width of the signal at location 11(c), which is the logical OR of the signal at location 11(a) and the signal at location 11(b), is 1.0 μs. As a result, the pulse width of the circulating heat enable signal pHE is 0.8 μs, and the pulse width of the discharge heat enable signal tHE is 1.0 μs. Note that, as in the first embodiment, the number of connected inverter circuits is not limited to 20.

[0049] From the above explanation, the discharge heat enable signal tHE, which passes through the pulse width extension circuit γ2, has a longer pulse width than the circulation heat enable signal pHE, which does not pass through the pulse width extension circuit γ2, making it possible to have different pulse widths. In this embodiment, an example in which the pulse width of the discharge heat enable signal tHE is extended by the pulse width extension circuit γ2 has been described, but it is not limited to this. The circulation heat enable signal pHE may pass through the pulse width extension circuit γ2, while the discharge heat enable signal tHE may not pass through the pulse width extension circuit γ2. In addition to the pulse width extension circuit γ2, the pulse width shortening circuit γ1 described in the first embodiment may also be incorporated into the wiring configuration. In other words, if the pulse width of the pulse for which power consumption is to be reduced is relatively shortened, the balance of overall power consumption on the discharge element substrate α0 can be adjusted, thereby resolving power shortages and surpluses of the discharge drive element and the circulation drive element, respectively.

[0050] (Third embodiment) Figure 13 shows an example of the overall configuration of a liquid dispensing device according to the third embodiment. The third embodiment differs from the first and second embodiments in that, since the heat enable signal HE is not transmitted from the main board β0, an external input terminal for receiving the heat enable signal HE is not implemented. Furthermore, since the heat enable signal HE is not transmitted from the main board β0, the dispensing element board α0 is equipped with a pulse width generation circuit γ4 that generates the heat enable signal HE, which is another difference from the first and second embodiments. The differences from the first and second embodiments will be explained below, and the explanation of the same configuration and functions as the first and second embodiments will be omitted.

[0051] (Pulse width generation circuit γ4) The ejection element substrate α0 in Figure 13 includes a pulse width generation circuit γ4. The clock signal CLK, data signal DATA, and latch signal LT are transmitted from the controller β1, via the control data supply circuit α3, and to the pulse width generation circuit γ4. The pulse width generation circuit γ4 generates a heat enable signal HE. The heat enable signal HE generated by the pulse width generation circuit γ4 is branched. One of the signals from which the heat enable signal HE is branched is transmitted as the ejection heat enable signal tHE. The other signal from which the heat enable signal HE is branched is transmitted via the pulse width shortening circuit γ1 as the circulating heat enable signal pHE. Figure 14 shows an example of the circuit configuration of the pulse width generation circuit γ4 in Figure 13. Figure 15 shows an example of pulse change by the pulse width generation circuit γ4 in Figure 14. The pulse width generation circuit γ4 includes an edge counter circuit, a logic circuit, and a gate circuit. The data signal DATA, which is the timing data for the heat enable signal HE, is input to the edge counter circuit. The data signal DATA is defined by the rising and falling timings of the PT signal. The data signal DATA is set in the edge count circuit at the rising edge of the LT signal. The edge counter circuit counts the edges of the clock signal CLK. For example, the edge counter circuit starts counting based on the data signal DATA, synchronized with the edges of the clock signal CLK. When the edge counter circuit finishes counting, it outputs carry signals 302 and 303 and stops operating. The logic circuit receives the carry signals 302 and the negative logic result of carry signals 303 as input. The logic circuit outputs the PT signal. The gate circuit outputs the result of the AND operation between the input PT signal and the LT signal as the heat enable signal HE. The output heat enable signal HE branches midway. One branch is output as is as the discharge heat enable signal tHE. The other branch is input to the pulse width reduction circuit γ1, where the pulse width is reduced and then output as the circulating heat enable signal pHE. As a result, it is possible to make the pulse width of the discharge heat enable signal tHE and the pulse width of the circulation heat enable signal pHE different.Furthermore, the pulse width reduction circuit γ1 used on the circulating heat enable signal pHE side is not limited. For example, a pulse width extension circuit γ2 may be used on the discharge heat enable signal tHE side. Alternatively, the pulse width reduction circuit γ1 may be incorporated into the discharge heat enable signal tHE side.

[0052] As described above, in this embodiment, compared to the first and second embodiments, the external input terminal PAD for the heat enable signal HE and the wiring for the heat enable signal HE on the outside of the discharge element substrate α0 can be reduced. Therefore, further cost increases for the liquid discharge head 1 can be suppressed. In addition, since the wiring for the heat enable signal HE on the outside of the discharge element substrate α0 does not need to be mounted, signal crosstalk can be suppressed.

[0053] In addition, while the first to third embodiments all use a configuration in which the pulse widths of the discharge heater RhA and the circulation heater RhB are different, the system is not limited to this. For example, the same configuration may be used to set different pulse widths for large and small discharge heaters of different sizes.

[0054] Furthermore, the pulse widths of the heating element (sub-heater) for maintaining the discharge element substrate α0 at a constant temperature and the discharge heater RhA may be configured to be different. Similarly, the pulse widths of the temperature sensing element (temperature sensor) capable of detecting the temperature inside the foam chamber and the discharge heater RhA may also be configured to be different. In addition, it is possible to adjust the pulse width in any other conceivable combination.

[0055] In the first embodiment, an example using a pulse width shortening circuit γ1 was described; in the second embodiment, an example using a pulse width extension circuit γ2 was described; and in the third embodiment, an example using a pulse width generation circuit γ4 and a pulse width shortening circuit γ1 was described. These pulse width adjustments may be combined, and a circuit that includes at least one pulse width adjustment function may be called a pulse width adjustment circuit. For example, in the first embodiment, a circuit including a pulse width shortening circuit γ1 may be called a pulse width adjustment circuit. In the second embodiment, a circuit including a pulse width extension circuit γ2 may be called a pulse width adjustment circuit. In the third embodiment, a circuit including a pulse width generation circuit γ4 and a pulse width shortening circuit γ1 may be called a pulse width adjustment circuit.

[0056] <Other Embodiments> Although various examples and embodiments of this disclosure have been described above, the spirit and scope of this disclosure are not limited to the specific descriptions herein. This disclosure is not limited to the embodiments described above, and various modifications may be made. Furthermore, this disclosure may combine some of the embodiments described above as appropriate.

[0057] (Variation 1) For example, in the first embodiment, a pulse width shortening circuit γ1 was described, in the second embodiment, a pulse width extension circuit γ2 was described, and in the third embodiment, an example of a combination of a pulse width shortening circuit γ1 and a pulse width generation circuit γ4 was described, but the invention is not limited thereto. For example, at least two of the pulse width shortening circuit γ1, pulse width extension circuit γ2, and pulse width generation circuit γ4 may be combined. Alternatively, at least one pulse width adjustment circuit that includes all the functions of the pulse width shortening circuit γ1, pulse width extension circuit γ2, and pulse width generation circuit γ4 may be implemented. For example, the pulse width adjustment circuit may have a DIP switch to indicate whether or not to use the functions of the pulse width shortening circuit γ1, pulse width extension circuit γ2, and pulse width generation circuit γ4. By setting the DIP switch appropriately and combining the pulse adjustment circuits, any pulse width adjustment may be made possible. Alternatively, the number of circuits combined may be changed, such as a combination of multiple pulse width shortening circuits γ1 and one pulse width generation circuit γ4.

[0058] The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions. Furthermore, the program may be recorded on a recording medium readable by a computer and provided.

[0059] The disclosure of this embodiment includes configurations represented by the following liquid dispensing head and liquid dispensing device.

[0060] <Configuration 1> A discharge module having a discharge drive element and a discharge heater electrically connectable to the discharge drive element, A circulation module is arranged in conjunction with the discharge module and includes a circulation drive element and a circulation heater electrically connectable to the circulation drive element. A pulse width control means that makes the pulse width for discharge, which controls the discharge drive element to a conductive state, and the pulse width for circulation, which controls the circulation drive element to a conductive state, different. A liquid dispensing head characterized by having the following features.

[0061] <Configuration 2> The liquid discharge head according to configuration 1, wherein the pulse width control means controls at least one of the discharge pulse width and the circulation pulse width.

[0062] <Structure 3> The liquid discharge head according to configuration 1, wherein the pulse width control means controls either the discharge pulse width or the circulation pulse width.

[0063] <Structure 4> The liquid discharge head according to configuration 3, wherein the pulse width control means includes a pulse width shortening circuit that shortens a heat enable signal which determines a reference drive pulse width common to the discharge drive element and the circulation drive element, and sets the circulation pulse width to a pulse width obtained by shortening the heat enable signal.

[0064] <Composition 5> The liquid discharge head according to configuration 3, wherein the pulse width control means includes a pulse width extension circuit that sets the pulse width obtained by extending the heat enable signal, which determines a common reference drive pulse width for the discharge drive element and the circulation drive element, as the discharge pulse width.

[0065] <Composition 6> The pulse width control means is A pulse width generation circuit that generates a heat enable signal that determines a common reference drive pulse width for the discharge drive element and the circulation drive element, A pulse width reduction circuit that uses the pulse width obtained by shortening the heat enable signal generated by the pulse width generation circuit as the circulating pulse width, A liquid dispensing head as described in configuration 3, including the liquid dispensing head.

[0066] <Composition 7> The aforementioned pulse width reduction circuit is A delay circuit that delays the heat enable signal, A logic AND circuit that outputs the logic AND of the signal delayed by the delay circuit and the heat enable signal, A liquid dispensing head as described in configuration 4, including the configuration described above.

[0067] <Structure 8> The pulse width extension circuit is A delay circuit that delays the heat enable signal, A logical OR circuit that outputs the logical OR of the signal delayed by the delay circuit and the heat enable signal, A liquid dispensing head as described in configuration 5, including the configuration described above.

[0068] <Composition 9> The liquid discharge head according to configuration 7 or 8, wherein the delay circuit includes a plurality of inverter circuits, and each of the plurality of inverter circuits is connected in series.

[0069] <Composition 10> The liquid dispensing head according to configuration 7 or 8, wherein the delay circuit includes a resistor and a capacitor, and the resistor and the capacitor are connected in series.

[0070] <Composition 11> The liquid discharge head according to configuration 9, wherein the delay amount of the delay circuit is 0.2 μs or less, and the difference between the discharge pulse width and the circulation pulse width is 0.2 μs or less.

[0071] <Composition 12> The liquid discharge head according to configuration 10, wherein the delay amount of the delay circuit is 0.2 μs or less, and the difference between the discharge pulse width and the circulation pulse width is 0.2 μs or less.

[0072] <Composition 13> The liquid discharge head according to configuration 6, wherein the pulse width generation circuit determines the drive pulse width based on a count value obtained by counting the edges of the input clock signal.

[0073] <Composition 14> Multiple units of the discharge module and the circulation module are provided in the same number. A liquid discharge head according to any one of configurations 1 to 8, further comprising control data supply means for exclusively selecting a circulation group, which is divided into predetermined numbers from a plurality of circulation modules, with respect to a discharge group, which is divided into predetermined numbers from a plurality of discharge modules.

[0074] <Composition 15> The liquid discharge head according to configuration 1, wherein the discharge heater and the circulation heater are connected to a common power supply voltage and a common ground potential.

[0075] <Composition 16> The liquid discharge head described in Configuration 1, wherein the discharge heater and the circulation heater are constructed using the same semiconductor process.

[0076] <Composition 17> The liquid discharge head described in configuration 1, wherein the discharge heater and the circulation heater are made of the same material.

[0077] <Composition 18> A liquid dispensing head as described in any one of configurations 1 to 8, A carriage equipped with the aforementioned liquid discharge head and which reciprocates in the main scanning direction, A conveyor roller is provided below the carriage to transport the discharged medium in the sub-scanning direction, A liquid dispensing device characterized by comprising the following features. [Explanation of symbols]

[0078] α1 Discharge Module α2 Circulation Module α3 Control Data Supply Circuit

Claims

1. A discharge module having a discharge drive element and a discharge heater electrically connectable to the discharge drive element, A circulation module is arranged in conjunction with the discharge module and includes a circulation drive element and a circulation heater electrically connectable to the circulation drive element. A pulse width control means that makes the pulse width for discharge, which controls the discharge drive element to a conductive state, and the pulse width for circulation, which controls the circulation drive element to a conductive state, different. A liquid dispensing head characterized by having the following features.

2. The liquid discharge head according to claim 1, wherein the pulse width control means controls at least one of the discharge pulse width and the circulation pulse width.

3. The liquid discharge head according to claim 1, wherein the pulse width control means controls either the discharge pulse width or the circulation pulse width.

4. The liquid discharge head according to claim 3, wherein the pulse width control means includes a pulse width shortening circuit that shortens a heat enable signal which determines a common reference drive pulse width for the discharge drive element and the circulation drive element, and sets the circulation pulse width to a shortened pulse width.

5. The liquid discharge head according to claim 3, wherein the pulse width control means includes a pulse width extension circuit that sets the pulse width obtained by extending a heat enable signal which determines a reference drive pulse width common to the discharge drive element and the circulation drive element to be the discharge pulse width.

6. The pulse width control means is A pulse width generation circuit that generates a heat enable signal that determines a common reference drive pulse width for the discharge drive element and the circulation drive element, A pulse width reduction circuit that uses the pulse width obtained by shortening the heat enable signal generated by the pulse width generation circuit as the circulating pulse width, A liquid dispensing head according to claim 3, including the following:

7. The pulse width reduction circuit is, A delay circuit that delays the heat enable signal, A logic AND circuit that outputs the logic AND of the signal delayed by the delay circuit and the heat enable signal, A liquid dispensing head according to claim 4, including the following:

8. The pulse width extension circuit is A delay circuit that delays the heat enable signal, A logical OR circuit that outputs the logical OR of the signal delayed by the delay circuit and the heat enable signal, A liquid dispensing head according to claim 5, including the following:

9. The liquid discharge head according to claim 7 or 8, wherein the delay circuit includes a plurality of inverter circuits, and each of the plurality of inverter circuits is connected in series.

10. The liquid dispensing head according to claim 7 or 8, wherein the delay circuit includes a resistor and a capacitor, and the resistor and the capacitor are connected in series.

11. The liquid discharge head according to claim 9, wherein the delay amount of the delay circuit is 0.2 μs or less, and the difference between the discharge pulse width and the circulation pulse width is 0.2 μs or less.

12. The liquid discharge head according to claim 10, wherein the delay amount of the delay circuit is 0.2 μs or less, and the difference between the discharge pulse width and the circulation pulse width is 0.2 μs or less.

13. The liquid discharge head according to claim 6, wherein the pulse width generation circuit determines the drive pulse width based on a count value obtained by counting the edges of the input clock signal.

14. Multiple units of the discharge module and the circulation module are provided in the same number. A liquid discharge head according to any one of claims 1 to 8, further comprising control data supply means for exclusively selecting a circulation group, which is divided into predetermined numbers from a plurality of circulation modules, with respect to a discharge group, which is divided into predetermined numbers from a plurality of discharge modules.

15. The liquid discharge head according to claim 1, wherein the discharge heater and the circulation heater are connected to a common power supply voltage and a common ground potential.

16. The liquid discharge head according to claim 1, wherein the discharge heater and the circulation heater are constructed using the same semiconductor process.

17. The liquid discharge head according to claim 1, wherein the discharge heater and the circulation heater are made of the same material.

18. A liquid dispensing head according to any one of claims 1 to 8, A carriage equipped with the aforementioned liquid discharge head and which reciprocates in the main scanning direction, A conveyor roller is provided below the carriage to transport the discharged medium in the sub-scanning direction, A liquid dispensing device characterized by comprising the following features.

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