Liquid dispensing head and liquid dispensing device

Abstract

Drive only one of the drive elements, the discharge drive element or the circulation drive element, independently. [Solution] The liquid discharge head 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; a group selection circuit configured to select at least one discharge group from discharge groups obtained by dividing a plurality of discharge modules into predetermined numbers, and to select at least one circulation group from circulation groups obtained by dividing a plurality of circulation modules into predetermined numbers; and a control means that determines whether or not to enable the selection by the group selection circuit based on the operating mode.

Description

Technical Field

[0005] ,

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

Background Art

[0002] Conventionally, among circulation-type liquid ejection devices that circulate a liquid (also referred to as ink), in a circulation flow path communicating with a discharge port, the ink in the circulation flow path is circulated by a circulation driving element different from the discharge driving element that discharges the ink. Further, Patent Document 1 discloses a technique for freely and individually selecting 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, the technique of Patent Document 1 can freely and individually select a discharge driving element and a circulation driving element, but data for individual selection must be transferred, increasing the data transfer amount. In order to reduce the data transfer amount, when configured to select a circulation driving element according to the selection of the discharge driving element, since the other is automatically selected according to one selection, only one of the discharge driving element and the circulation driving element cannot be selected. Therefore, there are cases where only one of the discharge driving element and the circulation driving element cannot be driven alone.

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; a group selection circuit configured to select at least one discharge group from discharge groups obtained by dividing a plurality of discharge modules into predetermined numbers, and to select at least one circulation group from circulation groups obtained by dividing a plurality of circulation modules into predetermined numbers; and a control means that determines whether or not to enable the selection by the group selection circuit based on the operating mode. [Effects of the Invention]

[0006] According to this disclosure, it is possible to drive only one of the discharge drive element and the circulation drive element independently. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows an example of the overall configuration of a liquid dispensing device. [Figure 2] This figure shows an example of the basic configuration of a liquid dispensing head. [Figure 3] This figure 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 103 shown in Figure 3. [Figure 5] This is a plan view of the ejection element substrate. [Figure 6] This is a plan view of the ejection element substrate. [Figure 7] This is a plan view of the ejection element substrate. [Figure 8] This is a plan view of the ejection element substrate. [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) In liquid ejection heads, for example, volatile components in the ink may evaporate from the ejection port, causing the ink inside the port to become thicker. This thickening of the ink can alter the ink ejection speed and other factors, potentially leading to ejection problems, including a decrease in ink placement accuracy. In particular, if the ink ejection process is paused for a long time, the increase in ink viscosity becomes more pronounced, causing solid particles in the ink to adhere to the inside of the ejection port, increasing ink flow resistance and making ink ejection problems more likely.

[0010] One known countermeasure against this thickening phenomenon of liquids is to flow fresh liquid into the discharge port in the liquid chamber. One method of flowing the liquid is to use a main body pump, separate from the fluid die that performs the discharge, to circulate the liquid in the head by pressure difference. Another known method is to circulate the liquid by equipping the fluid die itself with a circulation element. As a circulation element for the fluid die itself, a method of circulating the liquid by foaming a heating element (also referred to as Example 1) is also known. In Example 1, a fluid die is equipped with a fluid energy generating element (hereinafter also referred to as a circulation driving element), and a configuration is disclosed in which the liquid is circulated through the discharge port row between its two ends in a flow path that extends so as to intersect with the discharge port row.

[0011] In Example 1, address lines are assigned to both the discharge energy generation element (hereinafter also referred to as the discharge drive element) and the circulation drive element. If addressing is simply assigned to each drive element, drive data is required for each drive element, and the amount of data increases depending on the number of drive elements. As one example of a solution to this, a configuration can be considered in which the circulation drive element is automatically selected according to the bit selection of the discharge drive element. Specifically, in a case where a simultaneous discharge on selection signal and a time-division selection signal are used, the discharge heater is selected when the simultaneous discharge heater on selection signal is "1", and the pump heater (hereinafter also referred to as the circulation heater) is selected when it is "0". However, in this configuration, when the discharge drive element is driven, the circulation drive element is always selected at the same time, so it may not be possible to drive only one of the elements independently.

[0012] Therefore, in this disclosure, the group selection circuit selects at least one discharge group from discharge groups obtained by dividing a plurality of discharge modules into predetermined numbers. The group selection circuit also selects at least one circulation group obtained by dividing a plurality of circulation modules into predetermined numbers. Then, based on the operating mode, it is determined whether or not to enable the selection by the group selection circuit. With this control, it is possible to drive only one of the discharge drive element and the circulation drive element independently. The details of this disclosure will be described below.

[0013] (Liquid discharge device 50) Figure 1 shows an example of the overall configuration of the liquid dispensing device 50. Figure 1(a) is a schematic perspective view showing the liquid dispensing device 50 in which a main ink tank 2 is provided as a liquid storage unit outside the liquid dispensing head 1. Figure 1(b) is a schematic perspective view showing the liquid dispensing device 50 in which an ink sub-tank 54 is provided directly above the liquid dispensing head 1. First, the common parts of Figure 1(a) and Figure 1(b) will be explained.

[0014] 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 secondary 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 liquid ejection device 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 a serial-type inkjet liquid ejection device. This disclosure is also applicable to page-wide inkjet liquid ejection devices that eject liquid onto a medium P being transported in the transport direction Y by using a line head (page-wide type head) that is long in the page width direction of the ejection medium P. 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.

[0015] 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.

[0016] Next, the different parts of FIGS. 1(a) and 1(b) will be described. In FIG. 1(a), an ink sub-tank 54 is mounted on the liquid ejection head 1. Four ink supply tubes (liquid communication paths) 59 are attached to the ink sub-tank 54. Further, the liquid ejection device 50 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 through the four ink supply tubes 59 by the driving force of the external pump 21. On the other hand, in FIG. 1(b), the ink sub-tank 54 is provided directly above the liquid ejection head 1. In FIG. 1(b), the difference from FIG. 1(a) is that since the ink tank 2 is not provided outside the liquid ejection head 1, the four ink supply tubes 59 are not attached either, and the external pump 21 is not provided. In both FIGS. 1(a) and 1(b), the liquid ejection head 1 may be provided integrally with the ink sub-tank 54 and configured to be removable or attachable to the carriage 60. Alternatively, the ink sub-tank 54 may be provided integrally with the carriage 60 and only the ink sub-tank 54 may be configured to be removable or attachable. In the following description, the configuration of FIG. 1(a) will be used for the explanation.

[0017] (Liquid ejection head 1) FIG. 2 is a diagram showing a basic configuration example of the liquid ejection head 1 in FIG. 1. FIG. 2(a) is an exploded perspective view of the liquid ejection head 1 in FIG. 1. FIGS. 2(b), 2(c), and 2(d) are overall views of the ejection element substrate 100 in FIG. 2(a). The liquid ejection head 1 includes a housing portion 53, an ink sub-tank 54, and an ejection element unit 500. The ink sub-tank 54 is housed in the housing portion 53. The ejection element unit 500 is provided at the bottom of the housing portion 53. Although not shown, four joints connected to each of the four ink supply tubes 59 corresponding to four types of ink are provided on the wall surface of the housing portion 53. That is, individual ink supply paths are provided for each type of ink.

[0018] The ejection element unit 500 includes a first support member 505, a second support member 503, an ejection element substrate 100, and an electrical wiring member 501. An ink supply port and an ink recovery port are provided in the first support member 505. An opening is provided in the second support member 503. The ejection element substrate 100 is adhesively fixed to the first support member 505. The first support member 505 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 100. The electrical wiring member 501 applies an electrical signal for ejecting ink and an electrical signal for circulating ink to the ejection element substrate 100. Details of the electrical signal for ejecting ink and the electrical signal for circulating ink will be described later.

[0019] Figure 2(b) shows an example in which one ejection element substrate 100 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 in which one ejection element substrate 100 is configured for every two colors. Two ejection element substrates 100 may be mounted on one liquid ejection head 1. Alternatively, two liquid ejection heads 1, each mounted on one ejection element substrate 100, may be prepared. Figure 2(d) shows an example in which one ejection element substrate 100 is configured for every one color. Four ejection element substrates 100 may be mounted on one liquid ejection head 1. Alternatively, four liquid ejection heads 1, each mounted on a single ejection element substrate 100, may be prepared. Note that, as shown in Figures 2(c) and 2(d), if the ejection element substrate 100 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 100, 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 with reference to the circuit configuration.

[0020] (Discharge element substrate 100) Figure 3 shows an example of the circuit configuration of the discharge element board 100 shown in Figure 2. Various signals are supplied to the discharge element board 100 from the main board 200. The main board 200 is installed in the liquid discharge device body and includes a controller 201 and a power supply circuit 202. The controller 201 is mainly composed of ROM, RAM, and CPU, and controls the liquid discharge head 1 by supplying various electrical signals to the discharge element board 100. The controller 201 supplies the enable signal HE, clock signal CLK, data signal DATA, latch signal LT, discharge flag signal FLAG1, and cycle flag signal FLAG2 to the discharge element board 100. Details of each signal will be described later. The power supply circuit 202 applies a power supply voltage VH to the discharge element board 100. The power supply circuit 202 and the discharge element board 100 are connected by GNDH. GNDH functions as the ground potential.

[0021] (Wiring Overview) The ejection element substrate 100 comprises a plurality of ejection modules 101, a plurality of circulation modules 102, and a control data supply circuit 103. The circulation modules 102 are arranged in pairs with the ejection modules 101. Therefore, the number of circulation modules 102 is the same as the number of ejection modules 101. Discharge group selection signal wiring 106, circulation group selection signal wiring 107, and time-division selection signal wiring 108 are wired between the plurality of ejection modules 101 and the control data supply circuit 103. Discharge group selection signal wiring 106, circulation group selection signal wiring 107, and time-division selection signal wiring 108 are also wired between the plurality of circulation modules 102 and the control data supply circuit 103.

[0022] (Discharge module 101) The discharge module 101 includes a discharge heater RhA, a discharge driver element MD1, and a discharge logic circuit AND1. The discharge heater RhA is composed of, for example, an electrothermal conversion element. A voltage from the power supply voltage VH is applied to the discharge heater RhA, and if the discharge driver element MD1 is in a conductive state, current flows through the discharge heater RhA. The discharge driver element MD1 is composed of, for example, a MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor). However, the discharge driver element MD1 may be composed of something other than a MOSFET. For example, the discharge driver element MD1 may be composed of a bipolar transistor. Alternatively, the discharge driver element MD1 may be composed of an IGBT (Insulated Gate Bipolar Transistor). The discharge logic circuit AND1 selectively drives the discharge driver element MD1. An enable signal HE, a discharge group selection signal, and a discharge time-division selection signal are input to the input side of the discharge logic circuit AND1. The enable signal HE is transmitted from the controller 201. The enable signal HE 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 enable signal HE 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 100 and manufacturing variations in the power supply circuit 202. 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 targeted for simultaneous drive 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 enable signal HE can be transmitted from the controller 201 via an external connection terminal (not shown) provided on the ejection element board 100. The ejection group selection signal is supplied from the ejection group selection signal wiring 106.The time-division selection signal is supplied from the time-division selection signal wiring 108. 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 through the ejection heater RhA, generating heat in the ejection heater RhA. This series of operations makes it possible for the ink to foam before being ejected and then 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.

[0023] (Circulation module 102) The circulating module 102 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). However, 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. An enable signal HE, a circulating group selection signal, and a circulating time division selection signal are input to the input side of the circulating logic circuit AND2. The enable signal HE is transmitted from the controller 201. The enable signal HE 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 enable signal HE 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 100 and manufacturing variations in the power supply circuit 202. 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 enable signal HE can be transmitted from the controller 201 via an external connection terminal (not shown) provided on the discharge element substrate 100. The circulating group selection signal is supplied from the circulating group selection signal wiring 107. The time-division selection signal is supplied from the time-division selection signal wiring 108. The output side of the cyclic logic circuit AND2 is connected to the gate of the cyclic 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 enables the generation of circulating flow 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.

[0024] Furthermore, in order to reduce the number of signal terminals, the above-mentioned enable signal HE is shared by both the ejection and circulation heaters. Therefore, the current pulse width cannot be controlled individually for the ejection and circulation heaters. Thus, assuming that the ejection heater RhA and the circulation heater RhB are manufactured in the same process of the semiconductor manufacturing process and finished with the same manufacturing variation (amount of resistance deviation from the ideal value), the current pulse width may be adjusted with a single enable signal HE.

[0025] (Control data supply circuit 103) Figure 4 shows an example of the circuit configuration of the control data supply circuit 103 shown in Figure 3. Figure 4(a) shows an example of the internal wiring configuration of the control data supply circuit 103 shown in Figure 3. Figure 4(b) shows an example of the circuit configuration of the cyclic group selection circuit 113 shown in Figure 4(a) and an example of the circuit configuration of the discharge group selection circuit 112 shown in Figure 4(a). The control data supply circuit 103 includes shift registers 120a, 120b, latch circuits 121a, 121b, decoder circuit 122, cyclic group selection circuit 113, and discharge group selection circuit 112. The control data supply circuit 103 is also provided with an external connection terminal. The control data supply circuit 103 is supplied with a clock signal CLK, a data signal DATA, a latch signal LT, a discharge flag signal FLAG1, and a cyclic flag signal FLAG2 from the controller 201 via the external connection terminal. The clock signal CLK is used when serially transferring the data signal DATA to the shift registers 120a and 120b. The data signal DATA includes selection information for the discharge module 101 and selection information for the circulation module 102. The latch signal LT acquires and holds the information stored in the shift registers 120a and 120b, respectively, for each latch period. Details of the decoder circuit 122, the circulation group selection circuit 113, and the discharge group selection circuit 112 will be described later.

[0026] (Drive control of the discharge heater RhA) This section describes the drive control of ejector heaters RhA based on ejector heater array 109. The ejector heater array 109 consists of m groups. Each group contains n ejector heaters RhA. The ejector heaters RhA are positioned directly below the ink ejection port. When one group is selected, each of the n ejector heaters RhA within that group is operated sequentially in a time-division multiplexing manner. The ejector heater array is arranged in a 1-inch length at an array density of 600 dpi, and the drive control of (n=16) × (m=40 groups) of ejector heaters RhA is described.

[0027] (Time-division control within a single group) As described above, each ejection module 101 contains an ejection heater RhA. Furthermore, one group contains n ejection heaters RhA. Therefore, one group contains n ejection modules 101. Since we are assuming n=16, the 16 ejection modules 101 are time-division driven by a 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 101 for each divided time unit. Here, within the same group, multiple ejection modules 101 are never selected simultaneously. All ejection modules 101 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 time-division selection signal wirings 108 is selected. Therefore, by including the decoder circuit 122 in the control data supply circuit 103, the amount of data transferred serially from the main board 200 can be further reduced.

[0028] (Decoder circuit 122; time-division control) The decoder circuit 122 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 122, the decoder circuit 122 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 122 is output as information in which only 1 bit of the 16 bits is valid. This enables time-division multiplexing. Here, unless there is a special application, it is preferable to use all the time-division multiplexing selection signal wiring 108 output from the decoder circuit 122 as time-division multiplexing selection signals in terms of input data utilization efficiency. 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 200 and the output element board 100.

[0029] (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 103. When selecting one of the m groups, it is possible to simultaneously select n ejection modules 101 included in that group. Information equivalent to the number of groups, m bits, is serially transferred from the main board 200. As described above, the ejection module 101 is selected and controlled so that current flows to the corresponding ejection heater RhA when the enable signal HE, the ejection group selection signal, and the 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.

[0030] (Drive control of circulation module 102) This section describes the drive control of circulating heaters RhB based on a circulating heater array 110. The circulating heater array 110, like the discharge heater array 109, consists of m groups. Each group contains n circulating heaters RhB, similar to the discharge heater array 109. The circulating heaters RhB are arranged in close proximity to each other in pairs with the discharge heaters RhA. When one group is selected, each of the n circulating heaters RhB within that group is executed sequentially in a time-division multiplexer. This section describes the drive control of circulating heaters RhB for (n=16) × (m=40 groups).

[0031] (Time-division control within a single group) As described above, the circulating heater RhB is included in each circulating module 102. Also, one group contains n circulating heaters RhB. Therefore, one group contains n circulating modules 102. Furthermore, assuming n=16, the 16 circulating modules 102 are time-division driven with the same number of time divisions as the discharge module 101 by the time-division selection signal. To reduce the amount of data transmitted serially from the main board 200, the control data supply circuit 103 includes a decoder circuit 122 for the time-division selection signal.

[0032] (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 103. When selecting one of the m groups, it is possible to simultaneously select n cyclic modules 102 included in that group. Information equivalent to the number of groups, m bits, is serially transferred from the main board 200. As described above, the cyclic module 102 is selected and controlled so that current flows to the corresponding cyclic heater RhB when the enable signal HE, the cyclic group selection signal, and the time-division selection signal are input to the cyclic logic circuit AND2. However, the cyclic group selection signal is transferred from the cyclic group selection circuit 113 via the cyclic group selection signal wiring 107. The cyclic group selection circuit 113 is included in the control data supply circuit 103.

[0033] (Circulation group selection circuit 113) The cyclic group selection circuit 113 generates a cyclic group selection signal according to the selection information of the group selection generation signal. As shown in Figure 4(b), the cyclic group selection circuit 113 includes a NOT circuit and an AND circuit. The logical AND of the signal obtained by logically inverting the group selection generation signal obtained from the group selection generation signal wiring 105 using the NOT circuit and the cyclic flag signal FLAG2 obtained from the cyclic flag signal wiring 115 is processed as follows. That is, the result of the logical AND is output to the cyclic group selection signal wiring 107 as a cyclic group selection signal. Therefore, when the discharge module 101 is in a selected state, the cyclic module 102 is in a deselected state. On the other hand, when the discharge module 101 is in a deselected state and the cyclic flag signal FLAG2 is High, the cyclic module 102 is in a selected state. The group selection generation signal obtained from the group selection generation signal wiring 105 is acquired from the latch circuit 121b. The information held by the latch circuit 121b is obtained from the shift register 120b. The information held by the shift register 120b is obtained from the data signal DATA. In other words, the data signal DATA contains the selection information of the group selection generation signal.

[0034] (Discharge group selection circuit 112) The output group selection circuit 112 generates an output group selection signal according to the selection information of the group selection generation signal. As shown in Figure 4(b), the output group selection circuit 112 includes an AND gate. The result of the logical AND of the group selection generation signal obtained from the group selection generation signal wiring 105 and the output flag signal FLAG1 obtained from the output flag signal wiring 114 is processed as follows. That is, the result of the logical AND is output to the output group selection signal wiring 106 as an output group selection signal. Therefore, if the output module 101 is in a selected state and the output flag signal FLAG1 is High, the output module 101 is in a selected state. On the other hand, even if the output module is in a selected state, if the output flag signal FLAG1 is Low, the output module 101 is not in a selected state. That is, the output module 101 is not selected on a group basis.

[0035] Here, it can be controlled as shown in the following use cases.

[0036] (First use case) As a first use case, an operating mode is envisioned in which a normal ejection operation that does not require ink circulation is performed. In this first use case, the selection of the circulation module 102 can be prohibited by setting the circulation flag signal FLAG2 to Low, i.e., ineffective. For example, an operating mode can be set as the first mode in which the selection of the circulation module 102 by the circulation group selection circuit 113 is prohibited, and the selection of the ejection group by the ejection group selection circuit 112 is enabled. The liquid ejection device may operate based on this first mode.

[0037] (Second use case) A second use case is envisioned: an operating mode in which only ink circulation is performed without ink ejection. In this second use case, the selection of the ejection module 101 can be prohibited by setting the ejection flag signal FLAG1 to Low, i.e., inactive. For example, an operating mode can be set as the second mode in which the selection of the ejection group by the ejection group selection circuit 112 is prohibited, and the selection of the circulation module 102 by the circulation group selection circuit 113 is enabled. The liquid ejection device may operate based on this second mode.

[0038] (Third use case) A third use case is envisioned: an operating mode in which ink ejection and ink circulation are performed simultaneously. In this third use case, simultaneous ink ejection and ink circulation can be permitted by setting both the ejection flag signal FLAG1 and the circulation flag signal FLAG2 to High, i.e., enabled. For example, an operating mode can be set as the third mode in which the selection of the circulation module 102 by the circulation group selection circuit 113 is enabled, and the selection of the ejection group by the ejection group selection circuit 112 is enabled. The liquid ejection device may operate based on this third mode. It is preferable that the ejection flag signal FLAG1 and the circulation flag signal FLAG2 are transmitted serially from the liquid ejection device body via an external connection terminal.

[0039] In this embodiment, the discharge module 101 and the circulation module 102 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 within the discharge element board 100 for the discharge module 101 and the circulation module 102, respectively. In other words, they may be supplied individually from the power supply circuit 202 mounted on the main board 200.

[0040] 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 113, and other logic circuits such as the shift registers 120a, 120b, latch circuits 121a, 121b, and decoder circuit 122 may be composed of low-voltage MOS transistors.

[0041] (Circuit area) 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.

[0042] (Example 1 of circuit layout) Figure 5 is a plan view of the ejection element substrate 130. In one example in Figure 5, two systems of mechanisms for selective control are arranged from the control data supply circuit 103 to the ejection heater row 109 and the circulation heater row 110, with point symmetry based on the center of the ejection element substrate 130. In Figure 5, in the transport direction Y, three rows of ink supply port arrays 150 are arranged with spacing along the direction X. Between each ink supply port array 150, one row each of ejection heater row 109 and circulation heater row 110 is arranged along the transport direction Y. Of the three rows of ink supply port arrays 150, the left region of the left ink supply port array 150 and the right region of the right ink supply port array 150 are arranged as follows. Specifically, the following are arranged: discharge drive element MD1, circulation drive element MD2, discharge logic circuit AND1, circulation logic circuit AND2, discharge group selection signal wiring 106, circulation group selection signal wiring 107, and time division selection signal wiring 108.

[0043] 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 130. A control data supply circuit 103 is located in the area between the external connection terminals and the ink supply port arrangement 150. Since the area between the external connection terminals and the ink supply port arrangement 150 is located at two locations, above and below, in the transport direction Y, the control data supply circuit 103 is also located at two locations, above and below, in the transport direction Y.

[0044] As shown in Figure 5, since the ejection element substrate 130 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 130. Although not shown in the figure, if the arrangement configuration of the ejection element substrate 130 is considered as one unit, it is also possible to arrange multiple ejection element substrates 130 in the direction X to provide multiple ink types within a single ejection element substrate 130.

[0045] (Second example of circuit layout) Figure 6 is a plan view of the ejection element substrate 131. The group selection circuit 140 in Figure 6 is a combined representation of the ejection group selection circuit 112 and the circulation group selection circuit 113. The control data supply circuit 103 is located at two locations on the left and right ends of the ejection element substrate 131 in direction X. Compared to the example in Figure 5, the substrate dimensions in direction X are slightly larger, but the ejection element substrate 104 in Figure 6 can be arranged with smaller substrate dimensions in the transport direction Y, and the area of ​​the ejection element substrate 131 can also be made smaller than in Example 1.

[0046] (Third example of circuit layout) Figure 7 is a plan view of the discharge element substrate 132. Compared to the discharge element substrate 131 in Figure 6, the discharge element substrate 132 in Figure 7 has its external connection terminals located on one corner. This arrangement makes it possible to reduce the substrate dimensions in the Y direction. For a liquid discharge head that mounts multiple discharge element substrates 132 in the direction of the nozzle row, this configuration, in which the external connection terminals are not located on the extension of the nozzle row, allows for smaller spacing between discharge element substrates and thus reduces the size of the liquid discharge head.

[0047] (Fourth example of circuit layout) Figure 8 is a plan view of the ejection element substrate 133. In Figure 8, units including the control data supply circuit 103, ink supply port array 150, ejection heater row 109, circulation heater row 110, and ink supply port array 150 are arranged in line along direction X. This arrangement is configured such that the distance between each ink supply port array 150 is increased for each unit, assuming that different types of ink are supplied to the ink supply port array 150 on the ejection element substrate 133. With this configuration, it is possible to avoid mixing of inks of different types during ejection.

[0048] <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.

[0049] (Variation 1) For example, in this embodiment, an example has been described in which the discharge drive element MD1 and the circulation drive element MD2 are composed of DMOS transistors, but the embodiment is not limited to this. For example, at least one of the discharge drive element MD1 and the circulation drive element MD2 may be composed of a SiC (Silicon Carbide) MOSFET.

[0050] (Modification 2) Furthermore, while an example has been described in which the discharge flag signal FLAG1 and the cyclic flag signal FLAG2 are supplied from the controller 201 to the discharge element board 100, the explanation is not limited to this example. For example, the discharge flag signal FLAG1 and the cyclic flag signal FLAG2 may be extracted by the internal processing of the decoder circuit 122. Specifically, the decoder circuit 122 may include a discharge flag extraction filter and a cyclic flag extraction filter. For example, the data length of the data signal DATA input to the decoder circuit 122 is extended to provide a flag region. The discharge flag signal FLAG1 and the cyclic flag signal FLAG2 are held in this flag region. The discharge flag signal FLAG1 and the cyclic flag signal FLAG2 can be extracted from the data signal DATA via the discharge flag extraction filter and the cyclic flag extraction filter. The cyclic flag signal FLAG2 thus extracted may be transmitted to the cyclic group selection circuit 113 via, for example, wiring not shown. The discharge flag signal FLAG1 extracted as described above may also be transmitted to the discharge group selection circuit 112 via, for example, wiring not shown. Furthermore, the transmission timing may be adjusted using a latch signal LT or a clock signal CLK.

[0051] The disclosure of this embodiment includes configurations represented by the following liquid dispensing head and liquid dispensing device.

[0052] <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 group selection circuit configured to select at least one discharge group from discharge groups obtained by dividing a plurality of discharge modules into predetermined numbers, and to select at least one circulation group from circulation groups obtained by dividing a plurality of circulation modules into predetermined numbers, A control means that determines whether or not to enable the selection by the group selection circuit based on the operating mode, A liquid dispensing head characterized by having the following features.

[0053] <Configuration 2> The aforementioned operating mode includes at least one of a first mode, a second mode, and a third mode. The first mode is a mode in which the group selection circuit prohibits the selection of the circulation module and enables the group selection circuit to select the discharge module. The second mode is a mode in which the group selection circuit prohibits the selection of the discharge module and enables the group selection circuit to select the circulation module. The liquid discharge head according to configuration 1, wherein the third mode is a mode that enables the selection of the circulation module by the group selection circuit and enables the selection of the discharge module by the group selection circuit.

[0054] <Structure 3> The group selection circuit includes a discharge group selection circuit, The discharge group selection circuit includes a discharge logic AND circuit, The liquid dispensing head according to configuration 1 is configured such that the discharge logic AND circuit receives a group selection generation signal for selecting at least one discharge group from among the discharge groups, and a discharge flag signal that determines whether or not to enable the selection made by the group selection generation signal.

[0055] <Structure 4> The group selection circuit includes a cyclic group selection circuit, The aforementioned cyclic group selection circuit includes a cyclic logical AND circuit, The liquid discharge head according to Configuration 1, wherein the cyclic AND circuit is input to a group selection generation signal that selects at least one cyclic group from among the cyclic groups, and a cyclic flag signal that determines whether or not to enable the selection by the group selection generation signal.

[0056] <Composition 5> External connection terminals, The system further comprises a shift register that receives and holds the output flag signal input from the external connection terminal, The liquid dispensing head according to configuration 3 is configured such that the discharge flag signal held in the shift register is input to the discharge AND circuit for discharge.

[0057] <Composition 6> External connection terminals, The system further comprises a shift register that receives and holds the input of the cyclic flag signal from the external connection terminal, The cyclic AND circuit is a liquid dispensing head according to configuration 4, to which the cyclic flag signal held in the shift register is input.

[0058] <Composition 7> The liquid discharge head according to configuration 1, further comprising a decoder circuit that expands the number of output bits of the output data to a power of 2 for the number of input bits of the input data, with respect to the number of input bits of the input data, using the respective time division ratios of the discharge drive element and the circulation drive element.

[0059] <Structure 8> For each of the aforementioned discharge groups, the discharge drive element is driven by the aforementioned time division ratio. The liquid discharge head according to configuration 7, further comprising control means for driving the circulating drive element with the time division number for each of the circulating groups.

[0060] <Composition 9> The decoder circuit further comprises a variable that, with respect to the number of input bits of the input data, expands the number of output bits of the output data into a power of 2 of the number of input bits, using the time division ratio of the respective discharge drive element and the circulation drive element. The liquid dispensing head according to configuration 3, wherein the decoder circuit holds the dispensing flag signal extracted from the input data in the output data.

[0061] <Composition 10> The decoder circuit further comprises a variable that, with respect to the number of input bits of the input data, expands the number of output bits of the output data into a power of 2 of the number of input bits, using the time division ratio of the respective discharge drive element and the circulation drive element. The liquid discharge head according to configuration 4, wherein the decoder circuit holds the cycle flag signal extracted from the input data in the output data.

[0062] <Composition 11> 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.

[0063] <Composition 12> The liquid discharge head described in Configuration 1, wherein the discharge heater and the circulation heater are constructed using the same semiconductor process.

[0064] <Composition 13> The liquid discharge head described in configuration 1 is composed of the same material as the discharge heater and the circulation heater.

[0065] <Composition 14> A liquid dispensing head as described in any one of configurations 1 to 13, 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 being equipped with the following features. [Explanation of Symbols]

[0066] 100 Discharge element substrate 101 Discharge Module 102 Circulation Module 103 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 group selection circuit is configured to select at least one discharge group from discharge groups obtained by dividing a plurality of discharge modules into predetermined numbers, and to select at least one circulation group from circulation groups obtained by dividing a plurality of circulation modules into predetermined numbers, A control means that determines whether or not to enable the selection by the group selection circuit based on the operating mode, A liquid dispensing head characterized by having the following features.

2. The aforementioned operating mode includes at least one of a first mode, a second mode, and a third mode. The first mode is a mode in which the group selection circuit prohibits the selection of the circulation module and enables the group selection circuit to select the discharge module. The second mode is a mode in which the group selection circuit prohibits the selection of the discharge module and enables the group selection circuit to select the circulation module. The liquid discharge head according to claim 1, wherein the third mode is a mode that enables the selection of the circulation module by the group selection circuit and enables the selection of the discharge module by the group selection circuit.

3. The group selection circuit includes a discharge group selection circuit, The discharge group selection circuit includes a discharge logic AND circuit, The liquid dispensing head according to claim 1, wherein the dispensing AND circuit receives a group selection generation signal for selecting at least one dispensing group from among the dispensing groups, and a dispensing flag signal that determines whether or not to enable the selection by the group selection generation signal.

4. The group selection circuit includes a cyclic group selection circuit, The aforementioned cyclic group selection circuit includes a cyclic logical AND circuit, The liquid dispensing head according to claim 1, wherein the cyclic AND circuit is input to a group selection generation signal that selects at least one cyclic group from among the cyclic groups, and a cyclic flag signal that determines whether or not to enable the selection by the group selection generation signal.

5. External connection terminals, The system further comprises a shift register that receives and holds the output flag signal input from the external connection terminal, The liquid dispensing head according to claim 3, wherein the dispensing AND circuit is input to the dispensing flag signal held in the shift register.

6. External connection terminals, The system further comprises a shift register that receives and holds the input of the cyclic flag signal from the external connection terminal, The liquid dispensing head according to claim 4, wherein the cyclic AND circuit is input to the cyclic flag signal held in the shift register.

7. The liquid discharge head according to claim 1, further comprising a decoder circuit that expands the number of output bits of the output data to a power of 2 for the number of input bits of the input data, with respect to the number of input bits of the input data, using the respective time division ratios of the discharge drive element and the circulation drive element.

8. For each of the aforementioned discharge groups, the discharge drive element is driven by the aforementioned time division ratio. The liquid discharge head according to claim 7, further comprising control means for driving the circulating drive element with the time division number for each of the circulating groups.

9. The decoder circuit further comprises a variable that, with respect to the number of input bits of the input data, expands the number of output bits of the output data into a power of 2 for the number of input bits, using the time division ratio of the respective discharge drive element and the circulation drive element. The liquid dispensing head according to claim 3, wherein the decoder circuit holds the dispensing flag signal extracted from the input data in the output data.

10. The decoder circuit further comprises a variable that, with respect to the number of input bits of the input data, expands the number of output bits of the output data into a power of 2 for the number of input bits, using the time division ratio of the respective discharge drive element and the circulation drive element. The liquid dispensing head according to claim 4, wherein the decoder circuit holds the cycle flag signal extracted from the input data in the output data.

11. 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.

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

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

14. A liquid dispensing head according to any one of claims 1 to 13, 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 being equipped with the following features.

Images