Liquid ejecting head and liquid ejecting apparatus

Abstract

The invention relates to a liquid ejecting head and a liquid ejecting apparatus. The liquid ejecting head includes: an ejecting module including an ejecting driver element and an ejecting heater electrically connectable to the ejecting driver element; the circulation module comprises a circulation driver element and a circulation heater which can be electrically connected with the circulation driver element; and a controller that controls each of the ejection driver element and the circulation driver element to any one of a conductive state and a non-conductive state. An injection driving frequency used by the controller to drive the injection driver element and a loop driving frequency used by the controller to drive the loop driver element are different from each other.

Description

Technical Field

[0001] This disclosure relates to a liquid jet head and a liquid jetting device that jets liquid while circulating it. Background Technology

[0002] In circulating liquid jetting devices that circulate liquid (also known as ink), a device is conventionally known in which the ink in the circulating flow channel is circulated by a different circulation drive element than the jet drive element used to jet ink in the circulating flow channel communicating with the jet orifice. Furthermore, International Publication No. WO2018 / 190872 (hereinafter referred to as Document 1) discloses a technique for selectively driving the jet drive element and the circulation drive element. Summary of the Invention

[0003] A liquid jet head according to one aspect of the present disclosure includes: a jetting module including a jetting driver element and a jetting heater electrically connected to the jetting driver element; a circulation module arranged in pair with the jetting module and including a circulation driver element and a circulation heater electrically connected to the circulation driver element; and a control unit that controls each of the jetting driver element and the circulation driver element to either an on state or an off state, wherein the jetting drive frequency used by the control unit to drive the jetting driver element and the circulation drive frequency used to drive the circulation driver element are different from each other.

[0004] The features of this disclosure will become apparent from the following description of embodiments with reference to the accompanying drawings. The following description of the embodiments is by way of example. Attached Figure Description

[0005] Figure 1A To illustrate the perspective view of the liquid jetting device, a main ink cartridge serving as a liquid storage unit is provided outside the liquid jetting head;

[0006] Figure 1B To illustrate the perspective view of the liquid jetting device, a secondary ink cartridge is provided directly above the liquid jetting head;

[0007] Figure 2A This is an exploded perspective view of the liquid injection head in Figure 1.

[0008] Figure 2B A diagram illustrating an example of a spray element plate for four color configurations;

[0009] Figure 2C A diagram illustrating an example of a spray element plate for two color configurations;

[0010] Figure 2D The diagram illustrates an example of a spray element plate for a single color configuration;

[0011] Figure 3 A diagram illustrating an example of the circuit configuration of the injection element board for a first use case;

[0012] Figure 4 To show Figure 3 A diagram showing an example of the circuit configuration for a loop control circuit;

[0013] Figure 5 for Figure 3 Timing diagram of the injection element board;

[0014] Figure 6 A diagram illustrating an example of the circuit configuration of the injection element board for the second use case;

[0015] Figure 7 for Figure 6 Timing diagram of the injection element board;

[0016] Figure 8 This is a plan view of the spray element board;

[0017] Figure 9 This is a plan view of the spray element board;

[0018] Figure 10 A plan view of the injection element board; and

[0019] Figure 11 This is a plan view of the spray element board. Detailed Implementation

[0020] Preferred embodiments of the invention will be described in detail below with reference to the accompanying drawings. It should be noted that the following embodiments are not intended to limit the scope of this disclosure, and not all combinations of features described in the following embodiments are necessary for the solutions of this disclosure. It should be noted that the same constituent elements are denoted by the same reference numerals.

[0021] (Overview)

[0022] Traditionally, circulating liquid jetting devices for ink circulation are known. These devices include a liquid jet head. The purpose of ink circulation is to expel air bubbles from the flow channels of the liquid jet head and to prevent ink thickening near the discharge port. For ink circulation, systems using pressure differentials (hereinafter also referred to as "differential pressure systems") are well-known, for example. In a differential pressure system, the pressure on the side supplying ink to the jet orifice (also called the "inner side") is set higher than the pressure on the side recovering ink (also called the "outer side") by using a pressure regulating mechanism, etc. This pressure differential allows ink to flow from the inner side to the outer side. Here, to circulate the ink, it is necessary to return the ink that has flowed to the outer side to the inner side. For this, a pump is required. It should be noted that there is a configuration in which ink is circulated between the liquid jet head and the liquid jetting device body by placing a pump outside the jet head of the liquid jetting device body. Alternatively, there is also a configuration in which ink is circulated within the liquid jet head by placing a pump inside the liquid jet head. However, this circulation method using a differential pressure system requires mechanisms such as pressure regulating mechanisms and pumps. Therefore, the size of the liquid jetting equipment body and the liquid jetting head is often increased.

[0023] Therefore, as a method for circulating ink other than a differential pressure system, the method described below also exists. Specifically, there is a method in which a circulation driver element, different from the jet driver element used for jetting ink, is arranged in a circulation flow channel communicating with the jet orifice. A mechanism for circulating ink in a circulation flow channel by driving a circulation driver element having such an arrangement is also known.

[0024] Furthermore, a circuit configuration for selectively driving each of a plurality of jet driver elements and a plurality of circulation driver elements disposed in a jet element plate contained in a liquid jet head is disclosed. In this circuit configuration, the function of selectively driving each of the plurality of jet driver elements and the plurality of circulation driver elements is achieved by assigning an address to each of the plurality of jet driver elements and the plurality of circulation driver elements. Therefore, as the number of the plurality of jet driver elements and the plurality of circulation driver elements increases, the amount of data transmitted for the data signal used to individually assign an address also increases. As the amount of data transmitted increases, for example, the circuitry for handling problems such as crosstalk of the data signal also increases. For this reason, it is preferable not to increase the amount of data transmitted. In view of this, in order to reduce the amount of data transmitted, a configuration can be considered that transforms the selection information about the circulation driver elements in the jet element plate according to the selection information about the jet driver elements to select each circulation driver element. According to this configuration, the amount of data transmitted can be reduced. However, even in this configuration, each of the jet driver elements and the circulation driver elements is selected according to a data signal having the same driving frequency. First, the optimal timing for jetting ink and the optimal timing for circulating ink are different. Therefore, there are cases where the same drive frequency is the optimal drive frequency for the injection drive element, but not the optimal drive frequency for the cycle drive element. Therefore, in this disclosure, at least the injection drive frequency used to drive the injection drive element and the cycle drive frequency used to drive the cycle drive element are different from each other. According to this process, the cycle drive frequency can be set to a different drive frequency than the injection drive frequency, enabling the cycle drive element to be driven at the optimal drive frequency.

[0025] <Liquid Jetting Equipment 50>

[0026] Figure 1A and Figure 1B This is a diagram illustrating an example of the overall configuration of the liquid injection device 50. Figure 1A A perspective view of a liquid jetting device 50 is shown schematically. The liquid jetting device has a main ink cartridge 2, which serves as a liquid storage unit, disposed outside the liquid jetting head 1. Figure 1B A perspective view of a liquid jetting device 50 is shown schematically, in which a secondary ink cartridge 54 is positioned directly above the liquid jetting head 1. First, the description... Figure 1A and Figure 1B The public parts.

[0027] The liquid jetting apparatus 50 includes a liquid jetting head 1 and transport rollers 55, 56, 57, and 58. The liquid jetting head 1 is capable of scanning along a direction X intersecting the transport direction Y of the target medium P. The liquid jetting head 1 is mounted on a carriage 60. The carriage 60 reciprocates along a guide shaft 51 in the main scanning direction (also referred to as direction X). The transport rollers 55, 56, 57, and 58 transport the target medium P along a secondary scanning direction (also referred to as the transport direction Y) that intersects the main scanning direction (orthogonal to the main scanning direction in this embodiment). That is, the liquid jetting apparatus 50 is configured as a serial inkjet liquid jetting apparatus that jets liquid from the liquid jetting head 1 onto the target medium P transported along the transport direction Y, while simultaneously causing the liquid jetting head 1 to scan along direction X. It should be noted that the application of this disclosure is not limited to serial inkjet liquid jetting apparatuses. This disclosure can also be applied to page-width inkjet liquid ejection equipment, which uses a line-type head (page-width head) that is longer in the page-width direction of the target medium P to eject liquid onto the target medium P being conveyed in the transport direction Y. It should be noted that, in Figure 1A and Figure 1B In this context, the Z direction indicates the vertical direction. That is, the Z direction is the direction that intersects (or is orthogonal to) the XY plane specified by the X direction and the transport direction Y.

[0028] The liquid ejector head 1 is capable of ejecting four types of ink: black (K), cyan (C), magenta (M), and yellow (Y). The liquid ejector head 1 can print full-color images using these four types of ink. It should be noted that the ink ejected from the liquid ejector head 1 is not limited to the four types mentioned above. For example, this disclosure can also be applied to liquid ejector heads 1 that eject other types of ink (such as inks of specific colors). That is, the type and quantity of ink ejected from the liquid ejector head 1 are not limited.

[0029] Next, we will describe Figure 1A and Figure 1B The different parts. In Figure 1A In this configuration, a secondary ink cartridge 54 is mounted on the liquid ejector head 1. Four ink supply tubes (liquid communication channels) 59 are attached to the secondary ink cartridge 54. Furthermore, the liquid ejector device 50 includes an ink cartridge 2 and an external pump 21. The ink cartridge 2 stores ink. The ink stored in the ink cartridge 2 is supplied to the secondary ink cartridge 54 via the four ink supply tubes 59 by the driving force of the external pump 21. On the other hand, in... Figure 1B In this configuration, the secondary ink cartridge 54 is positioned directly above the liquid ejector head 1. Figure 1B In, with Figure 1A The difference lies in that, since the ink cartridge 2 is not located outside the liquid ejector head 1, it also lacks the four ink supply tubes 59 and an external pump 21. It should be noted that... Figure 1A and Figure 1B In both cases, the liquid injection head 1 can be integrated with the sub-ink cartridge 54 and configured to be detachable from or attached to the carriage 60. Alternatively, the sub-ink cartridge 54 can be integrated with the carriage 60, such that only the sub-ink cartridge 54 is configured to be detachable or attached. This will be achieved through the use of... Figure 1A The following description is based on the configuration.

[0030] <Liquid Jet Head 1>

[0031] Figure 2 is a diagram showing an example of the basic configuration of the liquid injection head 1 of Figure 1. Figure 2A This is an exploded perspective view of the liquid injection head 1 in Figure 1. Figure 2B , Figure 2C and Figure 2D for Figure 2A The image shows an overall view of the jetting element plate 101. The liquid jetting head 1 includes a housing unit 53, a sub-ink cartridge 54, and a jetting element unit 100. The sub-ink cartridge 54 is housed within the housing unit 53. The jetting element unit 100 is disposed on the bottom portion of the housing unit 53. Note that, although not shown in the figure, four connectors are provided on the wall surface of the housing unit 53, which connect to four corresponding ink supply tubes 59 corresponding to four types of ink. That is, a separate ink supply channel is provided for each type of ink.

[0032] The jetting element unit 100 includes a first support member 505, a second support member 503, a jetting element plate 101, and an electrical wiring member 501. The first support member 505 is provided with an ink supply port and an ink recovery port. The second support member 503 is provided with an opening. The jetting element plate 101 is bonded and fixed to the first support member 505. The first support member 505 is bonded and fixed to the second support member 503. The second support member 503 holds the electrical wiring member 501, such that the electrical wiring member 501 is electrically connected to the jetting element plate 101. The electrical wiring member 501 applies electrical signals for ink jetting and for ink circulation to the jetting element plate 101. Details of the electrical signals for ink jetting and for ink circulation will be described later.

[0033] Figure 2B An example of a jetting element plate 101 configured for four colors is shown. These four colors are, for example, black, cyan, magenta, and yellow, and the arrays are separated for each color. Each of the arrays is configured along the transport direction Y, and the arrays are spaced apart along the direction X. The plurality of jetting holes contained in each array are arranged at equal intervals along the direction Y. It should be noted that the jetting holes of each array can be arranged side-by-side in one array along the direction Y without any intervals in the direction X. Furthermore, black can be arranged in two arrays alone, resulting in a total of five arrays for the four colors, including black and the other three colors. Figure 2C An example of a single spray element plate 101 for two color configurations is shown. Two spray element plates 101 can be mounted in one liquid spray head 1. Alternatively, two liquid spray heads 1 can be prepared, each with one spray element plate 101 mounted in it. Figure 2D An example is shown with one spray element plate 101 for a single color configuration. Four spray element plates 101 can be mounted in one liquid spray head 1. Alternatively, four liquid spray heads 1 can be prepared, each with one spray element plate 101 mounted in it. It should be noted that, as Figure 2C and Figure 2D As shown, when the ink ejection element plate 101 is divided into multiple ink ejection element plates 101, all ink ejection element plates 101 need not have the same length. Furthermore, various other combinations of the number of colors in the ink ejection element plates 101 are possible, and this also applies to cases where the total number of colors is greater than four. In the following, details of the electrical signals for ejecting ink and the electrical signals for circulating ink will be described with reference to each use case, such as circuit configurations.

[0034] (First use case)

[0035] Figure 3 This diagram illustrates an example of the circuit configuration of the injection element board 101 in a first use case. The injection element board 101 is supplied with various signals by a motherboard 201. The motherboard 201 includes a controller 202 and a power supply circuit 203. The controller 202 is primarily configured with ROM, RAM, and a CPU, and controls the liquid injection head 1 by supplying various electrical signals to the injection element board 101. The controller 202 supplies each of the following to the injection element board 101: an enable signal HE, a latch signal LT, a data signal DATA, and a clock signal CLK. Details of each signal will be described later. Furthermore, the power supply circuit 203 supplies a supply voltage VH to the injection element board 101. The power supply circuit 203 and the injection element board 101 are connected via GNDH. GNDH serves as ground potential.

[0036] (Overview of wiring)

[0037] The injection element board 101 includes multiple injection modules 11, multiple circulation modules 12, and a control data supply circuit 31. The circulation modules 12 are arranged in pairs with the injection modules 11. Therefore, the number of circulation modules 12 is equal to the number of injection modules 11. Between the multiple injection modules 11 and the control data supply circuit 31, there are injection group selection signal lines 19, circulation group selection signal lines 20, injection time-minute selection signal lines 18, and circulation time-minute selection signal lines 33. Similarly, between the multiple circulation modules 12 and the control data supply circuit 31, there are injection group selection signal lines 19, circulation group selection signal lines 20, injection time-minute selection signal lines 18, and circulation time-minute selection signal lines 33.

[0038] (Injection Module 11)

[0039] The injection module 11 includes an injection heater RhA, an injection driver element MD1, and an injection logic circuit AND1. The injection heater RhA is configured with, for example, an electrothermal conversion element. The injection heater RhA is in a state where a voltage from the supply voltage VH is applied to it, and current flows through the injection heater RhA if the injection driver element MD1 is in the on state. The injection driver element MD1 is configured with, for example, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). It should be noted that the injection driver element MD1 can be configured with components other than a MOSFET. For example, the injection driver element MD1 can be configured with a bipolar transistor. Alternatively, the injection driver element MD1 can be configured with an IGBT (Insulated Gate Bipolar Transistor). The injection logic circuit AND1 selectively drives the injection driver element MD1. An enable signal HE, an injection group selection signal, and an injection time division selection signal are input to the input side of the injection logic circuit AND1. The enable signal HE is emitted from the controller 202. The enable signal HE controls the current pulse width of the injection driver element MD1, i.e., the time it takes to establish a conduction state between the drain and source of the injection driver element MD1, allowing current to flow continuously between the drain and source of the injection driver element MD1. The enable signal HE is used to adjust the current pulse width to generate more ideal thermal energy while taking into account various manufacturing deviations. These manufacturing deviations include, for example, manufacturing deviations in the resistance value of the injection heater RhA mounted in the injection element board 101, and manufacturing deviations in the power supply circuit 203. Furthermore, various manufacturing deviations also include the voltage drop of the power supply side wiring when multiple heaters (such as the injection heater RhA and the circulation heater RhB) are driven simultaneously. It should be noted that the heaters to be driven simultaneously are the injection heater RhA and the circulation heater RhB, with the circulation heater RhB positioned in a non-paired location with the injection heater RhA. The enable signal HE can be transmitted from the controller 202 via an external input terminal (not shown) provided on the injection element board 101. The injection group selection signal is supplied from the injection group selection signal wiring 19. The ejection timing selection signal is supplied from ejection timing selection signal wiring 18. The output side of the ejection logic circuit AND1 is connected to the gate of the ejection driver element MD1. Therefore, the ejection driver element MD1 is configured such that 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 driver element MD1, establishing a conduction state between the drain and source of the ejection driver element MD1. If a conduction state is established between the drain and source of the ejection driver element MD1, current flows through the ejection heater RhA, thereby generating heat in the ejection heater RhA. Through this series of operations, bubbles are generated in the ink, and the ink is ejected, allowing it to be ejected onto the ejection target medium P.It should be noted that although an example in which the jet heater RhA is configured with an electrothermal conversion element has been described, the jet heater RhA is not particularly limited thereto. For example, the jet heater RhA may be configured with a piezoelectric element.

[0040] (Loop Module 12)

[0041] The loop module 12 includes a loop heater RhB, a loop driver element MD2, and a loop logic circuit AND2. The loop heater RhB is configured with, for example, an electrothermal conversion element. The loop heater RhB is in a state where a voltage from the supply voltage VH is applied to the loop heater RhB, and current flows through the loop heater RhB if the loop driver element MD2 is in a conducting state. The loop driver element MD2 is configured with, for example, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). It should be noted that the loop driver element MD2 can be configured with components other than a MOSFET. For example, the loop driver element MD2 can be configured with a bipolar transistor. Alternatively, the loop driver element MD2 can be configured with an IGBT (Insulated Gate Bipolar Transistor). The loop logic circuit AND2 selectively drives the loop driver element MD2. An enable signal HE, a loop group selection signal, and a loop time division selection signal are input to the input side of the loop logic circuit AND2. The enable signal HE is emitted from the controller 202. The enable signal HE controls the current pulse width of the loop driver element MD2, i.e., the time it takes to establish a conduction state between the drain and source of the loop driver element MD2, allowing current to flow continuously between the drain and source of the loop driver element MD2. The enable signal HE is used to adjust the current pulse width to generate more ideal thermal energy while taking into account various manufacturing deviations. These manufacturing deviations include, for example, manufacturing deviations in the resistance value of the loop heater RhB mounted in the jet element board 101, and manufacturing deviations in the power supply circuit 203. Furthermore, various manufacturing deviations also include the voltage drop of the power supply side wiring when multiple heaters (such as the loop heater RhB and the jet heater RhA) are driven simultaneously. It should be noted that the enable signal HE can be emitted from the controller 202 via an external input terminal (not shown) provided on the jet element board 101. The loop group selection signal is supplied from the loop group selection signal wiring 20. The loop time division selection signal is supplied from the loop time division selection signal wiring 33. The output side of the loop logic circuit AND2 is connected to the gate of the loop driver element MD2. Therefore, the loop driver element MD2 is configured such that if all signals input from the input side of the loop logic circuit AND2 are 1, a voltage is applied to the gate of the loop driver element MD2, establishing a conduction state between the drain and source of the loop driver element MD2. If a conduction state is established between the drain and source of the loop driver element MD2, current flows through the loop heater RhB, thereby generating heat in the loop heater RhB. Through this series of operations, the ink bubbles increase in size, enabling circulating flow in the circulating flow channel for the ink. It should be noted that although an example in which the loop heater RhB is configured with an electrothermal conversion element has been described, the loop heater RhB is not particularly limited to this. For example, the loop heater RhB can be configured with a piezoelectric element.

[0042] It should be noted that, regarding the aforementioned enable signal HE, in order to reduce the number of signal terminals, inkjet and circulation share a single enable signal HE. Therefore, it is not possible to control the current pulse width separately for inkjet and circulation. Given this, assuming that the inkjet heater RhA and the circulation heater RhB are manufactured using the same steps in a semiconductor manufacturing process to achieve the same manufacturing tolerance (the amount of deviation of the resistance value from the ideal value), then a single enable signal HE can be used to adjust the current pulse width.

[0043] (Control data supply circuit 31)

[0044] The control data supply circuit 31 includes shift registers 13a, 13b, and 13c, latch circuits 14a, 14b, and 14c, a loop decoder circuit 32, a decoder circuit 15, and a loop group control circuit 16. Furthermore, the control data supply circuit 31 is provided with external input terminals. A clock signal CLK, a data signal DATA, and a latch signal LT are supplied from the controller 202 to the control data supply circuit 31 via these external input terminals. The clock signal CLK is used when serially transmitting the data signal DATA to the shift registers 13c, 13a, and 13b. The data signal DATA contains selection information regarding the injection module 11 and selection information regarding the loop module 12. The latch signal LT acquires and holds the information stored in each shift register 13c, 13a, and 13b during each latch cycle. Details of the loop decoder circuit 32, the decoder circuit 15, and the loop group control circuit 16 will be described later.

[0045] (Drive control of the jet heater RhA)

[0046] The drive control of the jet heaters RhA based on the jet heater array 21 will be described. The jet heater array 21 is configured with m groups. Each group contains n jet heaters RhA. The jet heaters RhA are positioned directly below the jetting orifice for ink. When a group is selected, each of the n jet heaters RhA in a group is executed sequentially in a time-division manner. The jet heater array is arranged side-by-side with a length of 1 inch and a density of 600 dpi, and the drive control of (n = 16) × (m = 40 groups) jet heaters RhA will be described.

[0047] (Time-division control within a group)

[0048] As described above, the injection heater RhA is contained within each injection module 11. Furthermore, a group contains n injection heaters RhA. Therefore, a group contains n injection modules 11. Furthermore, assuming n = 16, in time-division driving, the 16 injection modules 11 are driven by the injection time-division selection signal. Time-division driving is the control that divides a certain injection cycle time into n = 16 time units and sequentially selects the injection modules 11 one by one for each divided time unit. Here, multiple injection modules 11 are not selected simultaneously within the same group. Each of all injection modules 11 contained in the same group is necessarily selected at least once in a single injection cycle. In this time-division driving, the injection time-division selection signal wiring 18 is in a state where only one wiring is selected. Therefore, by providing a decoding circuit 15 in the control data supply circuit 31, the amount of data serially transmitted from the motherboard 201 can be further reduced.

[0049] (Decoding circuit 15; Time-division control)

[0050] Decoding circuit 15 is a circuit that expands the number of bits of output data relative to the number of bits q of input data to a power of 2 (2^q). Specifically, if 4 bits of input data are input into decoding circuit 15, decoding circuit 15 converts the 4 bits of input data into 2^4 = 16 bits of output data. In this case, the output data of decoding circuit 15 is output as information where only 1 bit of the 16 bits is valid. This achieves time-division driving. Here, as for the injection time-division selection signal wiring 18 output from decoding circuit 15, unless there is a special purpose, it is more preferable to use all wiring for the injection time-division selection signal from the perspective of input data utilization efficiency. It should be noted that as the amount of serially transmitted data increases, higher-speed serial transmission is required. Therefore, in motherboard 201 and injection element board 101, it is preferable to minimize the amount of data as much as possible, because this would lead to increased cost and size of signal transmitting circuit, signal receiving circuit, and transmitting lines.

[0051] (Group selection control)

[0052] To selectively drive any one of the m groups, an m-bit injection group selection signal is output from the control data supply circuit 31. When selecting one group from the m groups, n injection modules 11 contained in one group can be selected simultaneously. The same m-bit information as the number of groups is serially transmitted from the motherboard 201. As described above, the enable signal HE, the injection group selection signal, and the injection time division selection signal are input to the injection logic circuit AND1, thereby selectively controlling the injection module 11 so that current flows through the corresponding injection heater RhA. It should be noted that this embodiment describes an example assuming n = 16 and m = 40, but the configuration is not particularly limited to this. For example, a configuration of n = 8 and m = 80 can be used. Alternatively, a nozzle length different from this embodiment, such as n = 32 and m = 40, can be used. However, since n is a time division, it is preferable to represent n as a power of 2, such as 2, 4, 8, 16, or 32, so that the output signal of the decoding circuit 15 can be used as the selection signal.

[0053] (Drive control of loop module 12)

[0054] The drive control of the circulating heaters RhB based on the circulating heater array 22 will be described. The circulating heater array 22 is configured as m groups in the same manner as the jet heater array 21. Each group contains n circulating heaters RhB in the same manner as the jet heater array 21. The circulating heaters RhB are arranged in a one-to-one correspondence with the jet heaters RhA. When a group is selected, each of the n circulating heaters RhB in a group is executed sequentially in a time-division manner. The drive control of (n=16)×(m=40 groups) circulating heaters RhB will be described.

[0055] (Time-division control within a group)

[0056] As described above, each loop module 12 contains a loop heater RhB. Furthermore, a group includes n loop heaters RhB. Therefore, a group includes n loop modules 12. Furthermore, since n = 16 is assumed, the 16 loop modules 12 are driven by a loop time-division selection signal with a different time-division ratio than the injection module 11. In this embodiment, the time-division ratio of the loop module 12 is 32, which is twice the time-division ratio of the injection module 11 (n = 16). For the loop time-division selection signal, to reduce the amount of data serially transmitted from the motherboard 201, a loop decoding circuit 32 is included in the control data supply circuit 31.

[0057] (Cyclic decoding circuit 32; Time-division control)

[0058] The cyclic decoding circuit 32 is a circuit that expands the number of bits of the output data to a power of 2 relative to the number of bits q of the input data. Specifically, if 5 bits of input data are input into the cyclic decoding circuit 32, the cyclic decoding circuit 32 converts the 5 bits of input data into 2 to the power of 5 = 32 bits of output data. In this case, the output data of the cyclic decoding circuit 32 is output as information where only 1 bit of the 32 bits is valid. This achieves time-division driving. Here, the cyclic heaters RhB are configured in (n = 16) × (m = 40 groups). Therefore, 16 bits (i.e., half the number of bits of the output data is half of the 32-bit cyclic time-division selection signal) are used as the selection signal for the cyclic module 12, and the remaining 16 bits are not connected to any circuit and are not used. That is, of the 32 bits, half of the 16 bits are used for time-division, and the remaining 16 bits are not used for time-division, but are used as a delay time slot. Furthermore, when the injection module 11 runs a round by time-division driving, the cyclic module 12 is also driven by time-division driving. When injection module 11 runs two rounds via time-division drive, loop module 12 is not selected. In this way, when loop module 12 runs one round of time-division drive, injection module 11 runs two rounds of time-division drive. It should be noted that although the example described above uses 16 bits of the 32-bit system for time division and the remaining 16 bits for delay time slots, the configuration is not particularly limited to this. For example, 20 bits of the 32-bit system can be used for time division, and the remaining 12 bits can be used for delay time slots. That is, it is simply a matter of making the injection drive frequency and the loop drive frequency different from each other. Specifically, the time fraction of the loop time-division selection signal can be set to be greater than the time fraction of the injection time-division selection signal. As an example, in the first use case, the process of reducing the loop drive frequency (compared to the injection drive frequency) has been described.

[0059] (Group selection control)

[0060] To selectively drive any one of the m groups, an m-bit loop group selection signal is output from the control data supply circuit 31. When selecting one group from the m groups, n loop modules 12 contained within a single group can be selected simultaneously. The same m bits of information as the number of groups are serially transmitted from the motherboard 201. As described above, the enable signal HE, the loop group selection signal, and the loop time-division selection signal are input to the loop logic circuit AND2, thereby selectively controlling the loop module 12 so that current flows through the corresponding loop heater RhB. However, the loop group selection signal is transmitted from the loop group control circuit 16 via the loop group selection signal wiring 20. The loop group control circuit 16 is included in the control data supply circuit 31.

[0061] (Circuit group control circuit 16)

[0062] The cycle group control circuit 16 generates the cycle group selection signal based on the selection information of the injection group selection signal. Figure 4 To show Figure 3 A diagram illustrating an example of the circuit configuration of the loop group control circuit 16 is provided. The loop group control circuit 16 includes NOT gates and AND gates. The result of a logical AND operation between the signal obtained by logically inverting the injection group selection signal obtained from the injection group selection signal wiring 19 via the NOT gates and the loop flag signal obtained from the loop flag signal wiring 17 is processed as follows. Specifically, the result of the logical AND operation is output as the loop group selection signal to the loop group selection signal wiring 20. Therefore, when the injection module 11 is in the selected state, the loop module 12 is in the deselected state. On the other hand, when the injection module 11 is in the deselected state and the loop flag signal is high, the loop module 12 is in the selected state. That is, the paired injection module 11 and loop module 12 are selected exclusively by each other. It should be noted that when time-division selection is not performed, neither the injection module 11 nor the loop module 12 is selected.

[0063] (Time series diagram)

[0064] Figure 5 yes Figure 3 The timing diagram of the injection element board 101 is shown below. Clock signal CLK, data signal DATA, latch signal LT, and enable signal HE are input from the main board 201 to the injection element board 101. The injection time-division selection signal is time-divided into 1 to 16 bits in each latch cycle, thereby sequentially driving the injection driver element MD1 to allow current to flow through the corresponding injection heater RhA. Similarly, the cycle time-division selection signal is time-divided into 1 to 32 bits in each latch cycle, thereby sequentially driving the cycle driver element MD2. As described above, since the 16 bits of the cycle time-division selection signal are used as the selection signal for the cycle module 112, therefore... Figure 5As shown, during time units 1 to 16, current flows through the corresponding circulating heater RhB. However, for time units 17 to 32, which correspond to the remaining unused 16 bits in the cyclic time-division selection signal, the corresponding circulating heater RhB is not selected. That is, it is assumed that the ejection operation is performed at an ejection frequency of, for example, 30 kHz, and the time-division drive of the ejection heater array 21 completes one cycle within the ejection period. Based on this assumption, since the time-division of the circulating heater array 22 is set to twice that of the ejection heater array 21, the ink circulation operation can be performed at a frequency of 15 kHz (i.e., half the ejection frequency). Although 1 to 16 of the cyclic time-division selection signal are used in this embodiment, other combinations can be used. For example, even bits can be used instead of odd bits. Furthermore, the ink circulation operation can be further set to 1 / 4 or 1 / 8 of the ejection frequency by setting the time-division of the circulating heater array 22 to 4 or 8 times that of the ejection heater array 21. There are cases where the ejection drive frequency and the optimal frequency band in the ink circulation operation are different. By using the cycle time-division selection signal of the cycle heater array 22 (as shown in this embodiment), the cycle heater array 22 can be driven in such a way that the same optimal drive frequency as the ink cycle operation can be obtained, without considering the drive frequency of the jet heater array 21. Furthermore, in this embodiment, a cycle flag signal is provided to determine whether the cycle group selection signal can be enabled. By disabling the cycle flag signal, the selection of the cycle module 12 is disabled during normal jetting operations where ink cycle is not required. A system that serially transmits the cycle flag signal from the motherboard 201 is preferred.

[0065] In this embodiment, a common power supply voltage VH (e.g., 24V) is used as the power supply voltage for the injection module 11 and the circulation module 12, and a common GNDH is used as the ground potential. However, if it is desired to further reduce the fluctuations in injection energy caused by voltage drops when driving the injection heater RhA and the circulation heater RhB, the following measures are possible. Specifically, power supply wiring and external connection terminals for the power supply voltage and ground potential can be separately provided inside the injection element board 101 for the injection module 11 and the circulation module 12. That is, a configuration in which the power supply voltage and ground potential are supplied separately from the power supply circuit 203 installed in the main board 201 can be adopted.

[0066] Generally, since the driver elements operate at higher voltages than the logic circuits, a board containing both high-voltage driver elements and ordinary driver elements is used. In this embodiment, the jet driver element MD1 and the loop driver element MD2 can be configured with DMOS transistors (double-diffused MOSFETs) as high-voltage MOS transistors. Logic circuits such as the jet logic circuit AND1 and the loop logic circuit AND2, the loop group control circuit 16, and other shift registers 13a, 13b and 13c, latch circuits 14a, 14b and 14c, and the decoding circuit 15 can be configured with low-voltage MOS transistors.

[0067] (Second use case)

[0068] Figure 6 The diagram illustrates an example of the circuit configuration of the injection element board 102 for the second use case. Descriptions of the same configuration and functions as in the first use case will be omitted in the second use case. The second use case differs from the first use case in the following ways. Specifically, the second use case differs from the first use case in that the cyclic decoder circuit 32, latch circuit 14c, and shift register 13c are removed from the control data supply circuit 41, and a new injection cycle counter circuit 42 is added, along with time-division frequency-division signal wiring.

[0069] The control data supply circuit 41 includes an injection cycle counter circuit 42. The injection cycle counter circuit 42 is configured with a toggle circuit, for example, using a flip-flop. The injection cycle counter circuit 42 acquires an injection time-division selection signal from the injection time-division selection signal wiring 18. The injection cycle counter circuit 42 outputs a signal generated by alternately repeating the "high" and "low" states in the output logic of the injection time-division selection signal acquired in each cycle of the time-division drive of the injection heater RhA to the time-division frequency division signal wiring 43. The logic AND of the time-division frequency division signal wiring 43 and the injection time-division selection signal wiring 18 is input to the loop logic circuit AND2. In this way, the output logic of the loop logic circuit AND2 is set "low" every other cycle of the time-division drive of the injection heater RhA, and the loop driver element MD2 is in a non-conducting state. Therefore, for each other cycle of the time-division drive of the injection heater RhA, current is blocked from flowing through the loop heater RhB. In other words, when the time-division drive of the loop module 12 runs one round, the time-division drive of the injection module 11 runs two rounds, as in case 1.

[0070] (Time series diagram)

[0071] Figure 7 for Figure 6The timing diagram of the injection element board is shown below. Clock signal CLK, data signal DATA, latch signal LT, and enable signal HE are input from motherboard 201 to injection element board 101. The injection time division selection signal is time-divided into 1 to 16 in each latch cycle, thereby sequentially driving the injection driver element MD1 to allow current to flow through the corresponding injection heater RhA. In this embodiment, the logic of the time-division frequency division signal as the output signal repeats the "high" and "low" outputs each time the 16th rising edge of the time division in the injection time division selection signal is input to the injection cycle counter circuit 42. It should be noted that the injection time division selection signal can be selected from 1 to 16 in a random order. As described above, in the loop module 12, when the time-division frequency division signal is "high," the injection time division selection signal becomes active, causing current to flow through the corresponding loop heater RhB between injection time division time units 1 to 16, such as... Figure 7As shown. However, since the logic of the time division frequency division signal is "low" between time units 1 and 16 of the ejection time in the next cycle, the corresponding circulating heater RhB is not selected. Therefore, ink circulation operation can be performed at a frequency of 1 / 2 of the inkjet frequency with the same advantageous effect as in the first use case, while further suppressing the increase in circuit and wiring area compared to the first use case. In addition, ink circulation operation can also be performed at 1 / 4 or 1 / 8 of the ejection frequency by processing the period of the output logic of the switching time division frequency division signal to every 4 cycles or every 8 cycles relative to the ejection time division selection signal. The period of the output logic of the switching time division frequency division signal can be determined when designing the mask of the ejection element board 102, but it can also be configured to be transmitted serially along with the ejection heater selection information from the main board 201 so that the period can be freely changed according to the physical characteristics of the ink used. It should be noted that although an example of the ejection cycle counter circuit 42 being configured with a trigger circuit has been described, the configuration is not particularly limited to this. For example, the ejection cycle counter circuit 42 may not be configured with a trigger circuit, but may have a counter circuit. According to this circuit configuration, for example, for the injection time-division selection signal, the period of the output logic of the switching time-division frequency-division signal can also be processed to every 3 cycles, every 4 cycles, or every 5 cycles. In short, it simply requires making the injection drive frequency and the cycle drive frequency different from each other. As an example, in the second use case, the process of reducing the cycle period (compared to the injection cycle) has been described. For example, it is assumed that one cycle of the injection cycle is defined as a unit, and the cycle period is reduced. Under this assumption, for example, the following operation can be performed to reduce the cycle period to 3 cycles. Specifically, the following configuration can be adopted: wherein the cycle period is set to "high" in the first cycle of the injection cycle, and set to "low" in the second and third cycles of the injection cycle, and set to "high" in the fourth cycle of the injection cycle one cycle later. In short, for the injection time-division selection signal, the period of the output logic of the switching time-division frequency-division signal can also be processed for each predetermined cycle.

[0072] (Third use case)

[0073] The case of a lower injection frequency will be described. For example, in the case of driving cyclic operation at 15kHz relative to an injection frequency of 7.5kHz, the following configuration can be adopted. Specifically, it is assumed that the injection time-division selection signal is set to 32 bits, and of these 32 bits, bits 1 to 16 are used to select the injection heater RhA, while bits 17 to 32 are unused. Based on this assumption, the cycle time-division selection signal is set to 16 bits, and the operation is performed such that the cycle time-division runs two rounds while the injection time-division runs one round. According to this operation, the frequency of the cyclic operation can also be twice the injection frequency.

[0074] That is, as described above, the number of injection modules 11 and circulation modules 12 is set to be the same. In this configuration, the control data supply circuit 31 can be configured such that the time fraction of the injection time-division selection signal driving the injection driver element MD1 in a time-division manner is set to two or more times the time fraction of the circulation time-division selection signal driving the circulation driver element MD2 in a time-division manner. It should be noted that in the above example, an example has been described where 16 bits of the 32 bits are used for time division and the remaining 16 bits are used for delay time slots, but the configuration is not particularly limited to this. For example, in 32 bits, 20 bits are used for time division, and the remaining 12 bits are used for delay time slots. In short, it is simply a matter of making the injection drive frequency and the circulation drive frequency different from each other. Specifically, the time fraction of the injection time-division selection signal can be set to be greater than the time fraction of the circulation time-division selection signal. As an example, in the third use case, the process of reducing the injection drive frequency (compared to the circulation drive frequency) has been described.

[0075] (Circuit area)

[0076] The drive current of the circulating heater RhB generates heat to circulate the ink within each flow channel. When the drive current of the circulating heater RhB is less than the drive current of the jet heater RhA, which jets the ink onto the target medium, the current drive capability of the DMOS transistor can be smaller. Therefore, since it is not necessary for the area of ​​the circulating driver element MD2 to be larger than the area of ​​the jet driver element MD1, a configuration where the area of ​​the circulating driver element MD2 is smaller than the area of ​​the jet driver element MD1 is more preferable.

[0077] (First scenario of circuit layout)

[0078] Figure 8 This is a plan view of the injection element plate 103. Figure 8 In the example, two mechanisms for selection control are arranged in two systems that are symmetrical about the center point of the injection element plate 103, starting from the control data supply circuit 31 and spanning the injection heater array 21 and the circulating heater array 22. Figure 8 In the middle, along the conveying direction Y, three ink supply port arrays 23 are arranged at intervals along the direction X. It should be noted that in the following... Figures 9 to 11In this configuration, the transport direction Y and direction X are defined in the same way. That is, direction X is defined as the transverse direction of the paper surface, and the transport direction Y is defined as the longitudinal direction of the paper surface. Between every two ink supply port arrays 23, the jet heater array 21 and the circulation heater array 22 are each arranged in an array along the transport direction Y. In each of the three ink supply port arrays 23, in the area on the left side of the left ink supply port array 23 and the area on the right side of the right ink supply port array 23, the following are arranged: Specifically, the jet driver element MD1, the circulation driver element MD2, the jet logic circuit AND1, the circulation logic circuit AND2, the jet group selection signal wiring 19, the circulation group selection signal wiring 20, the jet time-division selection signal wiring 18, and the circulation time-division selection signal wiring 33 are arranged.

[0079] External connection terminals are arranged in the direction X at the upper and lower end portions of the inkjet element plate 103 along the conveying direction Y. A control data supply circuit 31 is provided in the area between the external connection terminals and the ink supply port array 23. Since the area between the external connection terminals and the ink supply port array 23 exists in both the upper and lower portions along the conveying direction Y, the control data supply circuit 31 is also provided in both the upper and lower portions along the conveying direction Y.

[0080] As mentioned above, such as Figure 8 As shown, the jetting element plate 103 is configured to be arranged along the transport direction Y, thereby reducing the plate size of the jetting element plate 103 in the direction X. Furthermore, although not shown in the figure, if the arrangement of the jetting element plates 103 is assumed to be a single unit, multiple arrangements of the jetting element plates 103 side by side in the direction X can be used to obtain a configuration that provides multiple ink types in a single jetting element plate 103.

[0081] (Second case of circuit layout)

[0082] Figure 9 This is a plan view of the injection element plate 104. (Compared to...) Figure 8 Compared to the spray element plate 103, in Figure 9 The cycle time selection signal wiring 33 is not provided on the injection element board 104. Therefore, the control data supply circuit 41 is provided on the left and right end portions of the injection element board 104 along the X direction. Although the board size along the X direction is larger than... Figure 8 The example is slightly larger, but Figure 9 The jetting element plate 104 can be arranged in a smaller plate size along the conveying direction Y. The area of ​​the jetting element plate can also be smaller than in the first case of circuit arrangement.

[0083] (Third scenario for circuit layout)

[0084] Figure 10 This is a plan view of the injection element plate 105. (Compared to...) Figure 9 Compared to the injection element plate 104, in Figure 10 On the jet element plate 105, external connection terminals are located on the left side along the X direction. Compared to the jet element plate 104, the plate size in the transport direction Y can be reduced. Although not shown in the figure, the wiring configuration of the jet element plate 105 is assumed to be a single unit. Based on this assumption, in the case of mounting multiple jet element plates 105 along the arrangement direction of the ink supply port array 23, in the current configuration where the external connection terminals are not located on the extension line of the ink supply port array 23, the space between the jet element plates 105 can be further reduced. Therefore, the size of the liquid jet head can also be reduced.

[0085] (Fourth scenario for circuit layout)

[0086] Figure 11 This is a plan view of the injection element plate 106. Figure 11 In this configuration, units including a control data supply circuit 41, an ink supply port array 23, an ejector heater array 21, a circulation heater array 22, and an ink supply port array 23 are arranged side-by-side along the X direction. This arrangement is based on the assumption that different ink types are supplied to the ink supply port arrays 23 in the ejector element plate 106, and the distance between the ink supply port arrays 23 in each unit is separated. This configuration prevents the mixing of different ink types during ejection.

[0087] <Other Embodiments>

[0088] Although this disclosure has been described to date by way of various examples and embodiments, the spirit and scope of this disclosure are not limited to the specific description herein. This disclosure is not limited to the embodiments described above, and various modifications can be made. Furthermore, portions of the embodiments described above can be combined as needed in this disclosure.

[0089] (Variation 1)

[0090] For example, although this embodiment has described an example in which each time interval between the on and off states of the injection driver element MD1 and the cycle driver element MD2 is equally divided, the configuration is not particularly limited thereto. For example, the time interval between the on states of the injection driver element MD1 and the cycle driver element MD2 may be different from the time interval between the off states of the injection driver element MD1 and the cycle driver element MD2.

[0091] (Variation 2)

[0092] Furthermore, for example, although an example in which the jet driver element MD1 and the cycle driver element MD2 are each configured with a DMOS transistor has been described in this embodiment, the configuration is not particularly limited thereto. For example, at least one of the jet driver element MD1 and the cycle driver element MD2 may be configured with a SiC (silicon carbide) MOSFET.

[0093] The embodiments of this disclosure can also be implemented by a computer that reads and executes computer-executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be more fully referred to as a "non-transitory computer-readable storage medium") to perform the functions of one or more embodiments described above and / or includes one or more circuits (e.g., application-specific integrated circuits (ASICs)) for performing the functions of one or more embodiments described above, and by a method executed by a computer that reads and executes computer-executable instructions from a storage medium to perform the functions of one or more embodiments described above and / or controls one or more circuits to perform the functions of one or more embodiments described above. The computer may include one or more processors (e.g., a central processing unit (CPU), a microprocessor unit (MPU)) and may include a separate computer or a network of separate processors to read and execute computer-executable instructions. The computer-executable instructions may be provided to the computer, for example, from a network or a storage medium. The storage medium may include one or more of, for example, a hard disk, random access memory (RAM), read-only memory (ROM), the memory of a distributed computing system, an optical disc (such as an optical disc (CD), a digital versatile optical disc (DVD), or a Blu-ray disc (BD)™), a flash memory device, a memory card, etc.

[0094] Other embodiments

[0095] Embodiments of the present invention can also be implemented by providing software (including computer program products of computer programs) that performs the functions of the above embodiments to a system or device via a network or various storage media, and the computer (central processing unit (CPU) or microprocessor unit (MPU) of the system or device) reads and executes the computer program.

[0096] This disclosure enables the driving of cyclic driver elements at an optimal drive frequency.

[0097] While this disclosure has been described with reference to embodiments, it should be understood that this disclosure is not limited to the disclosed embodiments. The scope of the following claims shall be given the broadest interpretation in order to cover all such modifications and equivalent structures and functions.

Claims

1. A liquid injection head, comprising: An injection module, the injection module including an injection driver element and an injection heater capable of being electrically connected to the injection driver element; A circulation module, arranged in pair with the injection module, includes a circulation drive element and a circulation heater electrically connected to the circulation drive element; as well as The control unit controls each of the injection drive element and the cycle drive element to either an on or off state, wherein The injection drive frequency used by the control unit to drive the injection driver element is different from the cyclic drive frequency used to drive the cyclic driver element.

2. The liquid injection head according to claim 1, wherein, The same number of the injection modules and the circulation modules were provided, and The control unit sets the time fraction of the cyclic time-division selection signal used to drive the cyclic driver element in a time-division manner to be greater than the time fraction of the injection time-division selection signal used to drive the injection driver element in a time-division manner.

3. The liquid injection head according to claim 2, further comprising: A decoding circuit that, in response to the number of input bits of the input data, expands the number of output bits of the output data, which is the hour fraction of the injection driver element, to a power of 2 of the number of input bits; as well as A cyclic decoding circuit that, in response to the number of input bits of input data, expands the number of output bits of output data, which is a time fraction of the cyclic driver element, to a power of 2 equal to the number of input bits plus 1.

4. The liquid injection head according to claim 2, wherein, The control unit drives the injection driver elements in the injection group in a time-division manner, and each injection group is divided into a predetermined number of injection modules. The control unit drives the cycle driver elements in the cycle group in a time-division manner, and each cycle group is divided into the predetermined number of multiple cycle modules.

5. The liquid injection head according to claim 4, wherein, The control unit exclusively selects the cycle group relative to the injection group.

6. The liquid jet head of claim 2 further includes a jet cycle counter circuit, the jet cycle counter circuit stopping the time-division drive of the cycle driver element based on the jet time-division selection signal for each predetermined cycle of the time-division drive of the jet heater performed by the jet driver element.

7. The liquid injection head according to claim 1, wherein, The same number of the injection modules and the circulation modules were provided, and The control unit sets the time fraction of the injection time fraction selection signal used to drive the injection driver element in a time-division manner to be greater than the time fraction of the cycle time fraction selection signal used to drive the cycle driver element in a time-division manner.

8. The liquid injection head according to claim 1, wherein, A common power supply voltage and a common ground potential are connected to the jet heater and the circulating heater.

9. The liquid injection head according to claim 1, wherein, The jet heater and the circulating heater are formed by the same semiconductor process.

10. The liquid injection head according to claim 1, wherein, The jet heater and the circulating heater are made of the same material.

11. A liquid jetting device, comprising: Liquid injection head; A carriage on which the liquid injection head is mounted and which reciprocates, the carriage being configured to reciprocate in the main scanning direction; as well as A conveyor roller, disposed below the carriage, conveys the jet target medium in the sub-scanning direction, wherein... The liquid injection head includes: An injection module, the injection module including an injection driver element and an injection heater capable of being electrically connected to the injection driver element; A circulation module, arranged in pair with the injection module, and the circulation module including a circulation drive element and a circulation heater electrically connected to the circulation drive element; and The control unit controls each of the injection drive element and the cycle drive element to either an on or off state, wherein The injection drive frequency used by the control unit to drive the injection driver element is different from the cyclic drive frequency used to drive the cyclic driver element.

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