Inkjet head and in-head control circuit

Abstract

This design allows for support of multiple drive circuits without increasing the size of the inkjet head connector used for external signal input and output. [Solution] The input / output circuit of the inkjet head's internal control circuit comprises a signal input path, first and second signal output paths, and a generation unit. The signal input path transmits signals input from the outside. The first signal output path is connected to the first drive circuit, and the second signal output path is connected to the second drive circuit. The generation unit generates a common control signal to control the first and second drive circuits based on the signals transmitted through the signal input path, and sends the generated common control signal to the first and second signal output paths.

Description

Technical Field

[0001] Embodiments of the present invention relate to an inkjet head and an in-head control circuit.

Background Art

[0002] As an image forming apparatus, an inkjet printer that ejects ink onto a printing medium to form an image is known. The inkjet printer includes, for example, an inkjet head and a head controller that controls the inkjet head.

[0003] The inkjet head includes, for example, a head unit and an in-head control circuit. The head unit includes an actuator having a capacitive load to which a plurality of capacitive elements are connected. The in-head control circuit includes a drive circuit (driver IC) that drives the actuator, an in-head control circuit that transmits data such as drive circuit setting data and print image data transmitted from the head controller to the drive circuit, and an input / output circuit that inputs and outputs various signals other than data between the head controller, the drive circuit, and the in-head control circuit. In such an inkjet head, drive circuit setting data such as a drive waveform is transferred to the drive circuit in advance, and print image data is sequentially transferred to the drive circuit in accordance with a print synchronization signal. In the inkjet head, a clock signal synchronized with the data and a reset signal for initialization are input from the head controller to the drive circuit, and conversely, a setting recognition signal for confirming that the drive circuit setting data has been normally transferred is output from the drive circuit to the head controller. There is a method of embedding an error detection code for determining this setting recognition signal.

[0004] In recent years, the requirements for higher printing speed and higher resolution have been increasing. In order to achieve higher resolution, multi-column use of multiple head units or widening of the arrangement of nozzles for ejecting ink in the head unit into multiple columns has been attempted. Along with this, the number of drive circuits in the inkjet head may also increase.

[0005] However, directly inputting and outputting clock signals, reset signals, and setting recognition signals between each of the multiple drive circuits would increase the number of input and output signals between the head controller and the inkjet head, leading to the problem of larger inkjet head connectors and the resulting increase in cost. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-138333 [Overview of the project] [Problems that the invention aims to solve]

[0007] The problem that the embodiments of the present invention aim to solve is to provide an inkjet head and an in-head control circuit that can accommodate multiple drive circuits without increasing the size of the connector for the inkjet head to perform signal input and output with the outside. [Means for solving the problem]

[0008] In one embodiment, the inkjet head includes first and second head units and an in-head control circuit. The first and second head units are arranged with a plurality of actuators for ejecting ink. The in-head control circuit controls the first and second head units and includes a first drive circuit, a second drive circuit, a first data transfer circuit, a second data transfer circuit, and an input / output circuit. The first drive circuit drives the first head unit according to first input data. The second drive circuit drives the second head unit according to second input data. The first data transfer circuit transfers first input data input from an external source to the first drive circuit. The second data transfer circuit transfers second input data input from an external source to the second drive circuit. The input / output circuit transmits signals input from an external source to the first and second drive circuits and includes a signal input path, a first signal output path, a second signal output path, and a generation unit. Signals input from an external source are transmitted through the signal input path. The first signal output path is connected to the first drive circuit. The second signal output path is connected to the second drive circuit. The generation unit generates a common control signal to control the first and second drive circuits based on the signal transmitted through the signal input path, and sends the generated common control signal to the first signal output path and the second signal output path. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is an explanatory diagram showing an example of the configuration of an inkjet printer in the first embodiment. [Figure 2] Figure 2 shows an example of the configuration of an inkjet head according to the first embodiment. [Figure 3] Figure 3 shows an example of the configuration of the head controller in the first embodiment. [Figure 4] Figure 4 shows an example of the configuration of the data processing unit in the in-head control circuit according to the first embodiment. [Figure 5] Figure 5 is a transition diagram of an example data format for print image data used to illustrate the operation of the inkjet head. [Figure 6] Figure 6 is a transition diagram of an example of a different data format for print image data to illustrate the operation of the inkjet head. [Figure 7] Figure 7 shows an example of the configuration of the in-head control circuit according to the second embodiment. [Figure 8] Figure 8 shows an example of the configuration of the data processing unit in the in-head control circuit according to the third embodiment. [Figure 9] Figure 9 shows an example of the data format for nozzle setting data. [Figure 10] Figure 10 shows an example of the configuration of the in-head control circuit according to the fourth embodiment. [Figure 11] Figure 11 shows an example of the configuration of the head controller in the fourth embodiment. [Modes for carrying out the invention]

[0010] The inkjet head and the in-head control circuit according to the embodiment will be described below with reference to the drawings.

[0011] [First Embodiment] Figure 1 is an explanatory diagram showing an example of the configuration of the inkjet printer 1 in the first embodiment. The inkjet printer 1 transports the printing medium, which is the recording medium, and forms an image on the printing medium.

[0012] The inkjet printer 1 comprises a control unit 11, a display 12, an operating unit 13, a communication interface 14, a transport motor 15, a motor drive circuit 16, a pump 17, a pump drive circuit 18, a plurality of (n: n is a natural number of 2 or more) inkjet heads 19-1, 19-2, ..., 19-n according to the first embodiment, a head controller 20, and a power supply 21. Furthermore, the inkjet printer 1 comprises a transport mechanism, a paper feed cassette, and an output tray, which are not shown. In each drawing, the interface is abbreviated as "IF". Also, in the following description, when describing the plurality of inkjet heads 19-1 to 19-n without distinction, they will simply be referred to as "inkjet head 19".

[0013] The control unit 11 comprises a processor 22 and a memory 23, and performs various controls on the inkjet printer 1. The processor 22 is an arithmetic element that performs calculations. The processor 22 performs various processes based on the program and the data used in the program stored in the memory 23, for example. The memory 23 stores the program, the data used in the program, etc., in a rewritable manner.

[0014] The display 12 is, for example, a display device such as a liquid crystal display, and displays an image in accordance with a video signal input from the processor 22 or a graphics controller (not shown) for image processing.

[0015] The operation unit 13 has an operation unit that generates operation signals based on user operations. The operation unit 13 may be, for example, a touch sensor, a numeric keypad, a power key, a paper feed key, various function keys, or a keyboard. The touch sensor may be, for example, a resistive touch sensor or a capacitive touch sensor. The touch sensor acquires information indicating a specified position within a certain area. Alternatively, the touch sensor may be used as a touch panel that is arranged on the top surface of the display 12 and configured as an integral part of it. In this case, the touch sensor generates a signal indicating the touched position on the screen displayed on the display 12.

[0016] The communication interface 14 is an interface for communicating with external devices. In this embodiment, the communication interface 14 is used, for example, for communication with at least one host PC 2 that transmits print data to the inkjet printer 1. The communication interface 14 communicates with the host PC 2 via a network 3 configured by wire or wirelessly, such as a LAN (Local Area Network).

[0017] The conveyance motor 15 serves as a drive source for a conveyance mechanism (not shown) for conveying the print medium by rotating. The conveyance mechanism is composed of a conveyance belt for conveying the print medium, a plurality of rollers (drive roller and driven roller) around which the conveyance belt is stretched, guides, and the like. The conveyance motor 15 rotates the drive roller to move the conveyance belt. The print medium moves along a conveyance path defined by a guide disposed in the vicinity of the conveyance belt.

[0018] The motor drive circuit 16 drives the conveyance motor 15 according to a conveyance control signal input from the control unit 11. The motor drive circuit 16, the conveyance motor 15, and the conveyance mechanism convey the print medium taken out from a paper feed cassette (not shown) through a plurality of inkjet heads 19 to a paper discharge tray (not shown). The paper feed cassette is a cassette that houses a plurality of print media. The paper discharge tray is a tray that houses the print media discharged from the inkjet printer 1.

[0019] The pump 17 supplies ink from the ink tank to the ink chamber of the inkjet head 19 via an ink supply path. The pump 17 is disposed on an ink supply path composed of a tube (not shown) that connects the ink tank and the ink chamber (pressure chamber) of the inkjet head 19.

[0020] The pump drive circuit 18 drives the pump 17 according to an ink supply control signal input from the processor 22.

[0021] The inkjet head 19 ejects ink onto the printing medium to form an image. Based on the drive power and control signals supplied from the head controller 20, it ejects ink onto the printing medium transported by the transport mechanism to form an image. Multiple inkjet heads 19 are provided, one for each ink color, for example, cyan, magenta, yellow, and black. For the sake of simplicity in the drawing, only one set of pump 17 and pump drive circuit 18 is shown in Figure 1, but there is at least one set for each color, and there may be one set for each of the multiple inkjet heads 19.

[0022] Each inkjet head 19 has an in-head control circuit 24 according to the first embodiment, and a plurality of head units, two in this embodiment, 25-1 and 25-2. In the following description, when the two head units 25-1 and 25-2 are described without distinction, they will simply be referred to as "head unit 25". The head unit 25 has a plurality of channels for ejecting ink. Each channel includes a nozzle for ejecting ink, a pressure chamber communicating with the nozzle, and an actuator that changes the volume of the pressure chamber. The in-head control circuit 24 is a control circuit that controls this head unit 25. The in-head control circuit 24 includes a drive circuit that selects a channel for ejecting ink from among the plurality of channels of the head unit 25 and drives the actuator by providing a drive signal. When the actuator of the head unit 25 is driven, the volume of the pressure chamber filled with ink changes, and ink is ejected from the nozzle.

[0023] The head controller 20 is connected to the control unit 11, power supply 21, and host PC 2, and is a circuit that controls multiple connected inkjet heads 19. By operating the inkjet heads 19, the head controller 20 causes ink to be ejected from actuators within the inkjet heads 19, thereby forming an image on the printing medium.

[0024] Power supply 21 converts AC power supplied from the commercial power source into DC power (DC voltage DCV). Power supply 21 uses the DC power as a driving power source to supply each component within the inkjet printer 1.

[0025] The inkjet head 19 and the head controller 20 will be described in detail below. First, the inkjet head 19 will be described with reference to Figure 2. Figure 2 is a diagram showing an example configuration of the inkjet head 19-1 according to the first embodiment. Note that Figure 2 only shows the inkjet head 19-1 as a representative of the multiple inkjet heads 19, and of course the other inkjet heads 19-2 to 19-n have a similar configuration.

[0026] As mentioned above, two head units 25-1 and 25-2 are connected to the head-mounted control circuit 24.

[0027] The head-mounted control circuit 24 includes data transfer circuits 26-1 and 26-2, drive circuits 27-1 and 27-2, and an input / output circuit. The input / output circuit includes a clock receiving circuit 28, a frequency conversion circuit 29, a reset generation circuit 30, and a setting recognition signal generation unit 31. Data transfer circuits 26-1 and 27-1 correspond to head unit 25-1, and data transfer circuits 26-2 and 27-2 correspond to head unit 25-2. In the following description, when describing data transfer circuits 26-1 and 26-2 without distinction, they will simply be referred to as "data transfer circuit 26," and when describing drive circuits 27-1 and 27-2 without distinction, they will simply be referred to as "drive circuit 27."

[0028] The data transfer circuit 26-1 is configured to control the drive circuit 27-1 based on data input via a data input path 32-11 connected to the inkjet head high-speed data transmission path DO11 from the head controller 20. Similarly, the data transfer circuit 26-2 is configured to control the drive circuit 27-2 based on data input via a data input path 32-12 connected to the inkjet head high-speed data transmission path DO12 from the head controller 20. In the following description, when the data input paths 32-11 and 32-12 are described without distinction, they will simply be referred to as "data input path 32".

[0029] The data transfer circuit 26 includes, as functional blocks, a data receiving circuit 33, a data processing unit 34, a data transmission circuit 35, a command analysis unit 36, a data counter 37, and a clock transmission circuit 38.

[0030] The data receiving circuit 33 receives various data from the head controller 20 via the data input path 32, synchronized with the data receiving clock. The data receiving clock is input from the clock receiving circuit 28. Specifically, the clock receiving circuit 28 receives a clock synchronized with the data, which is input via the clock signal input path 39 connected to the clock signal transmission path CLK from the head controller 20, and inputs the received clock as the data receiving clock to the data receiving circuit 33 of each data transfer circuit 26. The clock receiving circuit 28 also inputs the data receiving clock to the frequency conversion circuit 29. The data receiving circuit 33 transfers the received data to the data processing unit 34 and the command analysis unit 36. The data received by the data receiving circuit 33 includes a start bit, followed by a command and the data corresponding to that command.

[0031] The command analysis unit 36 ​​analyzes the commands contained in the data transferred from the data receiving circuit 33 and inputs the analysis results to the data processing unit 34. Commands include print commands that instruct printing, setting commands that instruct the settings of the drive circuit 27, etc. Print image data includes print commands and image data as data entities. Drive circuit setting data, etc., includes setting commands, etc. and setting data, etc. as data entities.

[0032] Furthermore, if the analysis result is a print command, the command analysis unit 36 ​​starts the data counter 37 from the start of receiving the image data as the data entity. The data counter 37 counts the data transmission clock. The data transmission clock is a print synchronization signal and is input from the frequency conversion circuit 29. The frequency conversion circuit 29 is composed of a PLL (Phase Locked Loop) or DLL (Delay Locked Loop), and generates the data transmission clock by converting the frequency of the data reception clock to a higher frequency.

[0033] If the analysis result input from the command analysis unit 36 ​​is a setting command, the data processing unit 34 forwards the drive circuit setting data, etc., received from the data receiving circuit 33 to the data transmission circuit 35. If the analysis result is a print command, the data processing unit 34 modifies the print image data based on the count of the data counter 37 and forwards the modified print image data to the data transmission circuit 35. This modification of the print image data by the data processing unit 34 involves adding fixed-value image data to the print image data, and the details of this process will be described later.

[0034] The data transmission circuit 35 transfers the data received from the data processing unit 34 to the drive circuit 27 in synchronization with the data transmission clock, which is a print synchronization signal.

[0035] Furthermore, the clock transmission circuit 38 receives the data transmission clock converted by the frequency conversion circuit 29 and transfers this data transmission clock to the drive circuit 27. Specifically, the clock transmission circuit 38 of the data transfer circuit 26-1 inputs the data transmission clock to the drive circuit 27-1 via the clock signal output path 40-1. Also, the clock transmission circuit 38 of the data transfer circuit 26-2 inputs the data transmission clock to the drive circuit 27-2 via the clock signal output path 40-2.

[0036] The drive circuit 27 is a driver IC that integrates a dedicated drive circuit for driving multiple actuators of the head unit 25. Based on data from the data processing unit 34, such as drive circuit setting data and printed image data, and the data transmission clock from the clock transmission circuit 38, the drive circuit 27 generates an analog drive signal to be applied to each actuator using the drive voltage from the head controller 20, and drives each actuator by applying that drive signal.

[0037] The reset generation circuit 30 receives a reset signal input via the reset signal input path 41 connected to the reset signal transmission path RST from the head controller 20, removes chatter, and generates a common reset signal for the drive circuits 27. The reset generation circuit 30 inputs the generated common reset signal to drive circuit 27-1 via the reset signal output path 42-1 and to drive circuit 27-2 via the reset signal output path 42-2. In this way, by inputting a common reset signal to each drive circuit 27, multiple drive circuits 27 can be reset simultaneously. Each reset drive circuit 27 can be initialized based on the drive circuit setting data input from the data transmission circuit 35.

[0038] When the drive circuit 27-1 has completed its initial setup and is ready for use, it inputs the setting recognition signal to the setting recognition signal generation unit 31 via the setting recognition signal input path 43-1. Similarly, when the drive circuit 27-2 has completed its initial setup and is ready for use, it inputs the setting recognition signal to the setting recognition signal generation unit 31 via the setting recognition signal input path 43-2. ​​In this first embodiment, since each drive circuit 27 outputs an open-drain circuit, the setting recognition signal input path 43-1 and the setting recognition signal input path 43-2 combine the setting recognition signals on the signal input path and input them to the setting recognition signal generation unit 31. In this case, the combined setting recognition signal input path 43-C is connected to a predetermined power line via a pull-up resistor 44. When all setting recognition signals have been provided, the setting recognition signal generation unit 31 outputs the setting recognition signal to the setting recognition signal output path 45 connected to the setting recognition signal receiving path CFG1 to the head controller 20. At this time, the setting recognition signal generation unit 31 removes chatter of the setting recognition signal transmitted through the setting recognition signal input path 43-C, that is, the setting recognition signal input path 43-1 and the setting recognition signal input path 43-2, and generates a setting recognition signal to be output to the setting recognition signal output path 45. In this way, the inkjet head 19-1 notifies the head controller 20 that initial setup has been completed in all of the drive circuits 27 of the machine and that it is ready for use.

[0039] Next, the head controller 20 will be explained in more detail with reference to Figure 3. Figure 3 is a diagram showing an example configuration of the head controller 20. Note that Figure 3 only shows the configuration of the inkjet head high-speed data transmission path and several signal communication paths.

[0040] The head controller 20 is a head control circuit that controls the operation of multiple inkjet heads 19 by issuing commands to each of them via inkjet head high-speed data transmission paths DOi1 and DOi2 (where i=1 to n). The head controller 20 includes an internal control circuit 46 and a high-speed data transmission circuit 47.

[0041] The head controller's internal control circuit 46 is a microcomputer with internal memory. The head controller's internal control circuit 46 is connected to each inkjet head 19 via a commonly connected clock signal transmission path CLK and a commonly connected reset signal transmission path RST. The head controller's internal control circuit 46 is also connected to each of the multiple inkjet heads 19 via separate setting recognition signal reception paths CFG1 to CFGn. Furthermore, the head controller's internal control circuit 46 is connected to a high-speed data transmission circuit 47 via a register read / write line REG (R / W) and a data line DATA.

[0042] The high-speed data transmission circuit 47 is a serializer connected to each of the multiple inkjet heads 19 via separate inkjet head high-speed data transmission paths DOi1 and DOi2. The high-speed data transmission circuit 47 transmits data from the control circuit 46 in the head controller to the destination inkjet head 19 via the inkjet head high-speed data transmission paths. Of the two head units 25-1 and 25-2 in the inkjet head 19, DOi1 transmits data for head unit 25-1, and DOi2 transmits data for head unit 25-2.

[0043] Furthermore, the number of nozzles, i.e., the number of actuators, provided by the head unit 25 does not necessarily have to match the number of actuator output terminals of the drive circuit 27. For example, as shown in Figure 2, the drive circuit 27 may have more actuator output terminals than the number of actuators of the head unit 25, and there may be actuator output terminals that are not connected to the actuators of the head unit 25. Alternatively, even if the physical number matches, there may be actuator output terminals of the drive circuit 27 to which only drive signals that do not actually drive the actuators are applied. In such cases, dummy unused image data is assigned as image data corresponding to the actuator output terminals that are not connected to the actuators or that only output drive signals that do not result in the actual driving of the actuators, and print image data with such unused image data assigned is input to the drive circuit 27.

[0044] The following describes how to add such dummy print image data with reference to Figure 4. Figure 4 is a diagram showing an example of the configuration of the data processing unit 34 in the head control circuit 24 according to the first embodiment. The data processing unit 34 includes a data determination unit 48, a data determination unit 52, an unused image data assignment unit 51, an unused nozzle number determination unit 49, and a fixed value storage unit 50.

[0045] The data determination unit 48 receives data from the data receiving circuit 33 and the analysis results from the command analysis unit 36, and based on the analysis results, transfers the input data to the data determination unit 52 or the unused image data assignment unit 51. For example, the data determination unit 48 can be configured as a demultiplexer. If the analysis result is a print command, the data determination unit 48 assumes that print image data has been input from the data receiving circuit 33, i.e., from the processor 22 of the inkjet printer 1 via the head controller 20, and transfers the input data to the unused image data assignment unit 51. If the analysis result is a setting command, the data determination unit 48 assumes that drive circuit setting data, etc., has been input, and transfers the input drive circuit setting data, etc., to the data determination unit 52.

[0046] The unused nozzle number determination unit 49 receives the count from the data counter 37 and outputs the count value as the nozzle number to the unused image data assignment unit 51.

[0047] The fixed value storage unit 50 stores fixed values ​​that will be unused print image data.

[0048] The unused image data assignment unit 51 is given, as known information, the number of an unnecessary nozzle that indicates an actuator output terminal of the drive circuit 27 that is not used for printing the print image data of the head unit 25, that is, an actuator output terminal that is not connected to an actuator or outputs only a drive signal that does not result in the actual driving of an actuator. Thus, in this first embodiment, which actuator output terminal is the terminal of the unnecessary nozzle number is uniquely determined by the head unit 25 equipped in the inkjet head 19.

[0049] The unused image data assignment unit 51 selects either the print image data input from the data determination unit 48 or the unused image data input from the fixed value storage unit 50 based on the nozzle number input from the unused nozzle number determination unit 49, and transfers the selected image data to the data determination unit 52 as print image data. For example, the unused image data assignment unit 51 can be configured as a multiplexer. If a nozzle number corresponding to an unused nozzle number given as known information is input to the unused image data assignment unit 51, it transfers the fixed value, which is unused image data input from the fixed value storage unit 50, to the data determination unit 52 as print image data. If a nozzle number that does not correspond to an unused nozzle number is input, the unused image data assignment unit 51 transfers the print image data input from the data determination unit 48 to the data determination unit 52 as print image data. In this way, when the nozzle number matches an unused nozzle number, the unused image data assignment unit 51 generates print image data by adding the fixed value unused image data to the print image data and transfers it to the data determination unit 52. As mentioned above, the count input to the unused nozzle number determination unit 49 is a count of the data transmission clock with a frequency lower than the data reception clock frequency, so the print image data input to the unused image data assignment unit 51 and the nozzle number are not synchronized. Since the unused image data assignment unit 51 generates image data based on the nozzle number, the image data transferred to the data determination unit 52 is synchronized with the data transmission clock.

[0050] The data determination unit 52 transfers the drive circuit setting data etc. transferred from the data determination unit 48 and the printed image data transferred from the unused image data assignment unit 51 to the subsequent data transmission circuit 35. For example, the data determination unit 52 can be configured as a multiplexer. If the drive circuit setting data etc. is transferred from the data determination unit 48, the data determination unit 52 transfers that drive circuit setting data etc. to the data transmission circuit 35, and if printed image data is transferred from the unused image data assignment unit 51, it transfers that printed image data to the data transmission circuit 35.

[0051] The operation of the inkjet head 19 according to the first embodiment will be described below with reference to Figure 5. Figure 5 is a transition diagram of an example data format of print image data used to explain the operation of the inkjet head 19. Figure 5 shows print image data where one line is 640 dots, and is an example of printing by two head units 25 via two drive circuits 27, each having 328 actuator output terminals. Here, the head unit 25 has, for example, 320 nozzles, each printing one dot, and the first four and last four of the 328 actuator output terminals are not connected to the nozzles of the head unit 25. Alternatively, the head unit 25 may have 321 or more nozzles, for example, 328 nozzles, the same number as the 328 actuator output terminals of the drive circuit 27, and each nozzle is connected to each actuator output terminal, but only 320 of them are active, and the first and last four nozzles are unused dummy nozzles, and only drive signals that do not result in the actual drive of the actuators are output from the actuator output terminals corresponding to these dummy nozzles of the drive circuit 27.

[0052] When using an inkjet head 19 with such a configuration, the processor 22 of the inkjet printer 1 conventionally supplied print image data, such as print image data ID 1, to the head controller 20. Print image data ID 1 consists of an 8-bit start bit followed by an 8-bit print command indicating that the data is print image data, and then the image data to be printed as the actual data. In the image data, a fixed value dummy data D is set as unused image data in the bits corresponding to the actuator output terminals of the drive circuit 27, which output drive signals that are not connected to the actuator of the head unit 25 or do not result in the actual drive of the actuator. In the bits of the image data that output drive signals that contribute to the drive of the actuator, 640 dots of usable image data corresponding to nozzle numbers #1 to #640 are set.

[0053] In contrast, in this first embodiment, the processor 22 generates print image data ID2 that does not include such dummy data D and supplies it to the head controller 20. The head controller 20 then generates print image data to be sent to each inkjet head 19 from this print image data ID2. Specifically, the head controller 20 generates two print image data IDs, ID3-1 and ID3-2, to be transferred to, for example, the inkjet head 19-1. Print image data ID3-1 is print image data that is sent to the data transfer circuit 26-1 of the in-head control circuit 24 of the inkjet head 19-1 via the inkjet head high-speed data transmission path DO11. Print image data ID3-2 is print image data that is sent to the data transfer circuit 26-2 of the in-head control circuit 24 of the inkjet head 19-1 via the inkjet head high-speed data transmission path DO12. Print image data ID3-1 includes an 8-bit start bit and an 8-bit print command, followed by 320 dots of image data corresponding to nozzle numbers #1 to #320. Print image data ID3-2 includes an 8-bit start bit and an 8-bit print command, followed by 320 dots of image data corresponding to nozzle numbers #321 to #640. In the following explanation, when print image data ID3-1 and ID3-2 are not distinguished, they will simply be referred to as "print image data ID3".

[0054] In the in-head control circuit 24 of the inkjet head 19 that receives such print image data ID3, the command analysis unit 36 ​​determines that the input data is print image data ID3, and the data processing unit 34 adds dummy data D of a fixed value as unused image data to the print image data ID3.

[0055] Specifically, in the data processing unit 34 of the data transfer circuit 26-1, the data determination unit 48 determines if the analysis result from the command analysis unit 36 ​​is a print command, that is, if the input data is print image data ID 3-1, it transfers it to the unused image data assignment unit 51.

[0056] The unused nozzle number determination unit 49 outputs the nozzle number to the unused image data assignment unit 51 according to the count from the data counter 37.

[0057] If the unused image data assignment unit 51 receives nozzle numbers #1 to #4 and nozzle numbers #325 to #328, which are nozzle numbers corresponding to the unused nozzle numbers provided as known information by the unused nozzle number determination unit 49, it assigns fixed value dummy data D, which is unused image data stored in the fixed value storage unit 50, to the image data that is the data entity of the print image data ID 3-1 input from the data determination unit 48. In this way, the unused image data assignment unit 51 generates print image data ID 4-1 by assigning four dummy data D to the beginning and end of the 320 dots of used image data corresponding to nozzle numbers #1 to #320 of the print image data ID 3-1. The unused image data assignment unit 51 then transfers this print image data ID 4-1 to the drive circuit 27-1 via the data determination unit 52.

[0058] Similarly, in the data processing unit 34 of the data transfer circuit 26-2, if nozzle numbers #321 to #324 and nozzle numbers #645 to #648, which are nozzle numbers set as unnecessary nozzle numbers based on known information, are input from the unused nozzle number determination unit 49, the unused nozzle number determination unit 51 adds fixed value dummy data D, which is unused image data stored in the fixed value storage unit 50, to the image data as the data entity of the print image data ID 3-2 input from the data determination unit 48. In this way, the unused image data determination unit 51 generates print image data ID 4-2 by adding four dummy data D before and after the 320 dots of used image data corresponding to nozzle numbers #321 to #640 of the print image data ID 3-2, and transfers the generated print image data ID 4-2 to the drive circuit 27-2 via the data determination unit 52.

[0059] Figure 6 is a transition diagram of an example of another data format for print image data to illustrate the operation of the inkjet head 19. Figure 6 shows print image data where one line is 320 dots, and is an example of printing by two head units 25 via two drive circuits 27, each having 640 actuator output terminals. In this example, the head unit 25 has 320 nozzles, each printing one dot, and the odd-numbered terminals of the 640 actuator output terminals are not connected to the nozzles of the head unit 25, while only the even-numbered terminals are connected to the nozzles of the head unit 25. Alternatively, the head unit 25 may have 321 or more nozzles, for example, 640 nozzles, the same number as the 640 actuator output terminals of the drive circuit 27, with each nozzle connected to each actuator output terminal, but only the even-numbered 320 nozzles are active, and the odd-numbered nozzles are unused dummy nozzles, and only drive signals that do not result in the actual drive of the actuators are output from the actuator output terminals corresponding to these dummy nozzles of the drive circuit 27.

[0060] When using an inkjet head 19 with such a configuration, the processor 22 of the inkjet printer 1 conventionally supplied print image data, such as print image data ID 5, to the head controller 20. Print image data ID 5 consists of an 8-bit start bit followed by an 8-bit print command indicating that the data is print image data, and then the image data to be printed as the actual data object. In the image data, fixed-value dummy data D is set as unused image data in the odd bits, which correspond to the actuator output terminals that output only drive signals that do not result in the actual operation of the actuator. In the even bits, which output drive signals that contribute to the operation of the actuator, 320 dots of image data for use corresponding to nozzle numbers #1 to #320 are set.

[0061] In contrast, in this first embodiment, the processor 22 generates print image data ID 6 that does not include such dummy data D and supplies it to the head controller 20. The head controller 20 then generates print image data to be sent to each inkjet head 19 from this print image data ID 6. Specifically, the head controller 20 generates two print image data sets, ID 7-1 and ID 7-2, to be transferred to, for example, the inkjet head 19-1. Print image data ID 7-1 is print image data that is sent to the data transfer circuit 26-1 of the in-head control circuit 24 of the inkjet head 19-1 via the inkjet head high-speed data transmission path DO 11. Print image data ID 7-2 is print image data that is sent to the data transfer circuit 26-2 of the in-head control circuit 24 of the inkjet head 19-1 via the inkjet head high-speed data transmission path DO 12. Print image data ID 7-1 includes an 8-bit start bit and an 8-bit print command, followed by 160 dots of image data corresponding to nozzle numbers #1 to #160. Print image data ID7-2 includes an 8-bit start bit and an 8-bit print command, followed by 320 dots of image data corresponding to nozzle numbers #161 to #320. In the following explanation, when print image data ID7-1 and ID7-2 are not distinguished, they will simply be referred to as "print image data ID7".

[0062] In the in-head control circuit 24 of the inkjet head 19 that receives such print image data ID 7, the command analysis unit 36 ​​determines that the input data is print image data ID 7, and the data processing unit 34 adds dummy data D of a fixed value as unused image data to the print image data ID 7.

[0063] Specifically, in the data processing unit 34 of the data transfer circuit 26-1, the data determination unit 48 determines if the analysis result from the command analysis unit 36 ​​is a print command, that is, if the input data is print image data ID 7-1, it transfers it to the unused image data assignment unit 51.

[0064] The unused nozzle number determination unit 49 outputs the nozzle number to the unused image data assignment unit 51 according to the count from the data counter 37.

[0065] If the unused image data assignment unit 51 receives an odd-numbered nozzle number, which is a nozzle number set as an unnecessary nozzle number based on known information, from the unused nozzle number determination unit 49, it assigns fixed-value dummy data D, which is unused image data stored in the fixed-value storage unit 50, to the image data that is the data entity of the print image data ID 7-1 input from the data determination unit 48. In this way, the unused image data assignment unit 51 assigns 160 dots of dummy data D corresponding to the odd-numbered nozzle number of the print image data ID 7-1 and generates print image data ID 8-1 by placing the image data to be used in the 160 dots corresponding to the even-numbered nozzle number. The unused image data assignment unit 51 then transfers this print image data ID 8-1 to the drive circuit 27-1 via the data determination unit 52.

[0066] Similarly, in the data processing unit 34 of the data transfer circuit 26-2, the unused image data assignment unit 51, when it receives an odd nozzle number, which is a nozzle number set as an unnecessary nozzle number based on known information, from the unused nozzle number determination unit 49, assigns fixed value dummy data D, which is unused image data stored in the fixed value storage unit 50, to the image data as the data entity of the print image data ID 7-2 input from the data determination unit 48. In this way, the unused image data assignment unit 51 assigns 160 dots of dummy data D corresponding to the odd nozzle numbers of the print image data ID 7-2, and generates print image data ID 8-2 by placing the image data to be used in the 160 dots corresponding to the even nozzle numbers, and then transfers the generated print image data ID 8-2 to the drive circuit 27-2 via the data determination unit 52.

[0067] As described above, the inkjet head 19 according to the first embodiment includes a head unit 25 on which a plurality of actuators for ejecting ink are arranged, a drive circuit 27 that drives the plurality of actuators of the head unit 25 according to input data, and a data transfer circuit 26 which is an example of a transmission circuit that transmits input data to the drive circuit 27. The data transfer circuit 26 includes a data receiving circuit 33 which is an example of a receiving unit that receives first print image data from a head controller 20 which is outside the inkjet head 19, a data processing unit 34 which is an example of a conversion unit that converts the received first print image data into second print image data which has a larger data volume than the first print image data, and a data transmission circuit 35 which is an example of a transmitting unit that outputs the converted second print image data as input data to the drive circuit 27. Thus, in the inkjet head 19 according to the first embodiment, instead of transferring a large amount of print image data from the head controller 20 to the inkjet head 19 in a short time, a first print image data with a small amount of data is transferred, and this first print image data is converted into a second print image data with the amount of data required by the drive circuit 27 within the inkjet head 19, and then transferred to the drive circuit 27. Therefore, according to the inkjet head 19 of the first embodiment, the same results can be obtained without transmitting a large amount of print image data in a short time, thus enabling an improvement in the data transfer speed from the head controller 20 to the inkjet head 19 at a low cost.

[0068] In the inkjet head 19 according to the first embodiment, the data processing unit 34 includes an unused image data addition unit 51, which is an example of an addition unit that converts the first print image data into a second print image data by adding unused image data that is not used when printing is performed by the inkjet head 19 to the received first print image data. Therefore, according to the inkjet head 19 of the first embodiment, the head controller 20 sends the first print image data, which is a fixed-value dummy data D that is unused image data not used when printing is performed by the inkjet head 19 and should originally be included in the second print image data required by the drive circuit 27, to the inkjet head 19, and the dummy data D can be added to the necessary parts of the first print image data within the inkjet head 19.

[0069] In the inkjet head 19 according to the first embodiment, the drive circuit 27 has a plurality of first actuator output terminals that output drive signals contributing to the driving of a plurality of actuators of the head unit 25, and a plurality of second actuator output terminals that output drive signals that do not result in the driving of a plurality of actuators. Here, the plurality of first actuator output terminals and the plurality of second actuator output terminals are fixed, and the unused image data assignment unit 51 converts the first print image data into second print image data so that drive signals based on unused image data are output from the second actuator output terminals. Therefore, according to the inkjet head 19 of the first embodiment, a second print image data can be obtained based on the first print image data, which matches the configuration of the first and second actuator output terminals of the drive circuit 27.

[0070] Furthermore, the in-head control circuit 24 according to the first embodiment is configured within an inkjet head 19 that includes a head unit 25 on which a plurality of actuators for ejecting ink are arranged, and includes a drive circuit 27 that drives the plurality of actuators of the head unit 25 according to input data, and a data transfer circuit 26 which is an example of a transmission circuit that transmits input data to the drive circuit 27. The data transfer circuit 26 includes a data receiving circuit 33 which is an example of a receiving unit that receives first print image data from a head controller 20 which is outside the inkjet head 19, a data processing unit 34 which is an example of a conversion unit that converts the received first print image data into second print image data with a larger data amount than the first print image data, and a data transmission circuit 35 which is an example of a transmitting unit that outputs the converted second print image data as input data to the drive circuit 27. In this way, the in-head control circuit 24 according to the first embodiment converts the first print image data with a small data amount into second print image data with a data amount required by the drive circuit 27 and transfers it to the drive circuit 27. Therefore, according to the head control circuit 24 of the first embodiment, the same result can be obtained without transmitting a large amount of print image data from the head controller 20 to the inkjet head 19 in a short time, thus enabling an improvement in the data transfer speed from the head controller 20 to the inkjet head 19 at low cost.

[0071] Furthermore, the inkjet head 19 according to the first embodiment includes first and second head units 25-1, 25-2 on which a plurality of actuators for ejecting ink are arranged, and an in-head control circuit 24 that controls the first and second head units 25-1, 25-2. The in-head control circuit 24 includes a first drive circuit 27-1 that drives the first head unit 25-1 according to first input data, a second drive circuit 27-2 that drives the second head unit 25-2 according to second input data, a first data transfer circuit 26-1 that transfers first input data input from a head controller 20 which is outside the inkjet head 19 to the first drive circuit 27-1, a second data transfer circuit 26-2 that transfers second input data input from the head controller 20 to the second drive circuit 27-2, and an input / output circuit that transmits signals input from the head controller 20 to the first and second drive circuits 27-1, 27-2. The system includes a clock signal input path 39 or a reset signal input path 41, which is an example of a signal input path through which signals input from the head controller 20 are transmitted; a reset signal output path 42-1, which is an example of a first signal output path connected to the first drive circuit 27-1; a reset signal output path 42-2, which is an example of a second signal output path connected to the second drive circuit 27-2; and a clock receiving circuit 28, a frequency conversion circuit 29 and a clock transmitting circuit 38, or a reset generating circuit 30, which is an example of a generation unit that generates a data transmission clock or a reset signal, which is an example of a common control signal that controls the first and second drive circuits 27-1 and 27-2 based on the signals transmitted through the clock signal input path 39 or the reset signal input path 41, and sends the generated common data transmission clock or reset signal to the clock signal output path 40-1 and the clock signal output path 40-2 or the reset signal output path 42-1 and the reset signal output path 42-2. Therefore, according to the inkjet head 19 of the first embodiment, clock signals and reset signals, which are individually required for each drive circuit 27-1 and 27-2 but only need to be input / output once to the inkjet head 19, are consolidated by the head controller 20 and input to the inkjet head 19, and then separated into separate clock signals and reset signals by the in-head control circuit 24 and input to each individual drive circuit 27, thereby reducing the number of input signals from the head controller 20 to the inkjet head 19. Consequently, according to the inkjet head 19 of the first embodiment, it is possible to accommodate multiple drive circuits 27 without increasing the size of the connector of the inkjet head 19.

[0072] Here, the reset generation circuit 30, which is an example of the generation unit of the inkjet head 19 according to the first embodiment, eliminates chattering of the reset signal that is input from the outside and transmitted through the reset signal output path 42-1 and the reset signal output path 42-2. Therefore, according to the inkjet head 19 of the first embodiment, a reset signal with chatter removed can be input to each drive circuit 27, and the reset of each drive circuit 27 can be performed stably.

[0073] Furthermore, the inkjet head 19 according to the first embodiment includes first and second head units 25-1, 25-2 on which a plurality of actuators for ejecting ink are arranged, and an in-head control circuit 24 that controls the first and second head units 25-1, 25-2. The in-head control circuit 24 includes a first drive circuit 27-1 that drives the first head unit 25-1 according to first input data, a second drive circuit 27-2 that drives the second head unit 25-2 according to second input data, a first data transfer circuit 26-1 that transfers first input data input from a head controller 20 which is outside the inkjet head 19 to the first drive circuit 27-1, a second data transfer circuit 26-2 that transfers second input data input from the head controller 20 to the second drive circuit 27-2, and the first and second drive circuits 27-1, 27 The system includes an input / output circuit that transmits a signal output from -2 to the head controller 20, and the input / output circuit includes a setting recognition signal input path 43-1 which is an example of a first signal input path connected to the first drive circuit 27-1, a setting recognition signal input path 43-2 which is an example of a second signal input path connected to the second drive circuit 27-2, a setting recognition signal output path 45 which is an example of a signal output path through which a signal to be output to the head controller 20 is transmitted, and a setting recognition signal generation unit 31 which is an example of a generation unit that generates a setting recognition signal which is an example of a status signal indicating the state of the first and second drive circuits 27-1 and 27-2 based on the signal from the first drive circuit 27-1 transmitted through the setting recognition signal input path 43-1 and the signal from the second drive circuit 27-2 transmitted through the setting recognition signal input path 43-2, and sends the generated setting recognition signal to the setting recognition signal output path 45. Therefore, according to the inkjet head 19 of the first embodiment, although each drive circuit 27-1 and 27-2 individually requires a setting recognition signal, only one such signal is needed for input and output to the inkjet head 19. By consolidating these signals in the in-head control circuit 24 and outputting them from the inkjet head 19, the number of output signals from the inkjet head 19 to the head controller 20 can be reduced. Consequently, according to the inkjet head 19 of the first embodiment, it is possible to accommodate multiple drive circuits 27 without increasing the size of the connector of the inkjet head 19.

[0074] Furthermore, the in-head control circuit 24 according to the first embodiment is an in-head control circuit 24 configured within an inkjet head 19 having first and second head units 25-1, 25-2 on which a plurality of actuators for ejecting ink are arranged, and comprises: a first drive circuit 27-1 that drives the first head unit 25-1 according to first input data; a second drive circuit 27-2 that drives the second head unit 25-2 according to second input data; a first data transfer circuit 26-1 that transfers first input data input from a head controller 20 which is outside the inkjet head 19 to the first drive circuit 27-1; a second data transfer circuit 26-2 that transfers second input data input from the head controller 20 to the second drive circuit 27-2; and an input / output circuit that transmits signals input from the head controller 20 to the first and second drive circuits 27-1, 27-2, wherein the input / output circuit is connected to the head controller The circuit includes a clock signal input path 39 or a reset signal input path 41, which is an example of a signal input path through which a signal input from 20 is transmitted; a reset signal output path 42-1, which is an example of a first signal output path connected to the first drive circuit 27-1; a reset signal output path 42-2, which is an example of a second signal output path connected to the second drive circuit 27-2; and a clock receiving circuit 28, a frequency conversion circuit 29 and a clock transmitting circuit 38, or a reset generating circuit 30, which is an example of a generation unit that generates a data transmission clock or a reset signal, which is an example of a common control signal that controls the first and second drive circuits 27-1 and 27-2 based on the signal transmitted through the clock signal input path 39 or the reset signal input path 41, and sends the generated common data transmission clock or reset signal to the clock signal output path 40-1 and the clock signal output path 40-2 or the reset signal output path 42-1 and the reset signal output path 42-2. Therefore, according to the head control circuit 24 of the first embodiment, although each drive circuit 27-1 and 27-2 individually requires a clock signal and a reset signal, which only need to be input / output once to the inkjet head 19, the head controller 20 consolidates these signals and inputs them to the inkjet head 19. The head control circuit 24 then separates them into separate clock signals and reset signals, which can then be input to each individual drive circuit 27. This reduces the number of input signals from the head controller 20 to the inkjet head 19. Consequently, according to the inkjet head 19 of the first embodiment, it is possible to accommodate multiple drive circuits 27 without increasing the size of the connector of the inkjet head 19.

[0075] Furthermore, the in-head control circuit 24 according to the first embodiment is an in-head control circuit 24 configured within an inkjet head 19 that includes first and second head units 25-1 and 25-2 on which a plurality of actuators for ejecting ink are arranged, and includes a first drive circuit 27-1 that drives the first head unit 25-1 according to first input data, a second drive circuit 27-2 that drives the second head unit 25-2 according to second input data, a first data transfer circuit 26-1 that transfers first input data input from a head controller 20 which is outside the inkjet head 19 to the first drive circuit 27-1, a second data transfer circuit 26-2 that transfers second input data input from the head controller 20 to the second drive circuit 27-2, and signals output from the first and second drive circuits 27-1 and 27-2 The system includes an input / output circuit that transmits the signal to the head controller 20, and the input / output circuit includes a setting recognition signal input path 43-1 which is an example of a first signal input path connected to the first drive circuit 27-1, a setting recognition signal input path 43-2 which is an example of a second signal input path connected to the second drive circuit 27-2, a setting recognition signal output path 45 which is an example of a signal output path through which signals to be output to the head controller 20 are transmitted, and a setting recognition signal generation unit 31 which is an example of a generation unit that generates a setting recognition signal which is an example of a status signal indicating the state of the first and second drive circuits 27-1 and 27-2 based on the signal from the first drive circuit 27-1 transmitted through the setting recognition signal input path 43-1 and the signal from the second drive circuit 27-2 transmitted through the setting recognition signal input path 43-2, and sends the generated setting recognition signal to the setting recognition signal output path 45. Therefore, according to the head control circuit 24 of the first embodiment, although each drive circuit 27-1 and 27-2 individually requires a setting recognition signal, only one such signal is needed for input and output to the inkjet head 19. By consolidating these setting recognition signals in the head control circuit 24 and outputting them from the inkjet head 19, the number of output signals from the inkjet head 19 to the head controller 20 can be reduced. Consequently, according to the inkjet head 19 of the first embodiment, it is possible to accommodate multiple drive circuits 27 without increasing the size of the connector of the inkjet head 19.

[0076] Here, the setting recognition signal generation unit 31, which is an example of the generation unit of the inkjet head 19 according to the first embodiment, removes chatter of the setting recognition signal transmitted through the setting recognition signal input paths 43-1 and 43-2, which are examples of the first and second signal input paths. Therefore, according to the inkjet head 19 of the first embodiment, a setting recognition signal with chatter removed can be input from the inkjet head 19 to the head controller 20, and the state recognition of the drive circuit 27 in the head controller 20 can be performed stably.

[0077] Furthermore, the inkjet printer 1 according to the first embodiment includes a processor 22 that generates print image data and an inkjet head 19 that performs printing according to the print image data transmitted from the processor 22. The processor 22 creates a second print image data by deleting unused image data that will not be used when printing is performed by the inkjet head 19 from a first print image data corresponding to the image to be printed, based on the configuration of the inkjet head 19, and transmits the created second print image data to the inkjet head 19. The inkjet head 19 includes a head unit 25 in which a plurality of actuators for ejecting ink are arranged, and according to the input data The head unit 25 includes a drive circuit 27 that drives multiple actuators of the head unit 25, and a data transfer circuit 26 which is an example of a transmission circuit that transmits input data to the drive circuit 27. The data transfer circuit 26 includes a data receiving circuit 33 which is an example of a receiving unit that receives second print image data from a processor 22 which is outside the inkjet head 19 via the head controller 20, a data processing unit 34 which is an example of a conversion unit that converts the second print image data into first print image data by adding unused image data to the received second print image data, and a data transmission circuit 35 which is an example of a transmitting unit that outputs the converted first print image data as input data to the drive circuit 27. Thus, according to the inkjet printer 1 of the first embodiment, the processor 22 transmits to the inkjet head 19 via the head controller 20 a second print image data from which fixed-value dummy data D, which is unused image data not used when printing is performed by the head unit 25 and should originally be included in the first print image data required by the drive circuit 27, has been removed. The inkjet head 19 then restores the original first print image data by adding the dummy data D to the necessary parts of the second print image data. Therefore, according to the inkjet printer 1 of the first embodiment, the same results can be obtained without transmitting a large amount of print image data in a short time, thus enabling an inexpensive improvement in the data transfer speed from the processor 22 to the inkjet head 19 via the head controller 20.

[0078] [Second Embodiment] Next, a second embodiment will be described. Here, the same parts as in the first embodiment will be omitted from the description, and only the parts that differ from the first embodiment will be described. Figure 7 is a diagram showing an example of the configuration of the in-head control circuit 24 according to the second embodiment.

[0079] In the head-mounted control circuit 24 according to the second embodiment, the setting recognition signal output from the drive circuit 27-1 is input to the setting recognition signal generation unit 31 via the setting recognition signal input path 43-1. Similarly, the setting recognition signal output from the drive circuit 27-2 is input to the setting recognition signal generation unit 31 via the setting recognition signal input path 43-2. ​​In this way, the setting recognition signals output from the drive circuits 27-1 and 27-2 are input to the setting recognition signal generation unit 31 via the respective setting recognition signal input paths 43-1 and 43-2.

[0080] Furthermore, in this second embodiment, the setting recognition signal generation unit 31 is configured as a logical AND circuit. Therefore, when all setting recognition signals are provided, the setting recognition signal generation unit 31 outputs a setting recognition signal to the setting recognition signal output path 45 connected to the setting recognition signal reception path CFG1 to the head controller 20. As a result, the inkjet head 19 notifies the head controller 20 that initial setup has been completed in all of its drive circuits 27 and that it is ready for use.

[0081] As described above, in the inkjet head 19 and the in-head control circuit 24 according to the second embodiment, the setting recognition signal generation unit 31 generates a setting recognition signal and sends it to the setting recognition signal output path 45 when both the signal from the first drive circuit 27-1 and the signal from the second drive circuit 27-2 are obtained. Therefore, according to the inkjet head 19 and in-head control circuit 24 of the second embodiment, the head controller 20 can be notified that the setting is complete on an inkjet head 19 basis, rather than on a drive circuit 27 basis.

[0082] [Third Embodiment] Next, a third embodiment will be described. Here, the same parts as in the first and second embodiments will be omitted from the description, and only the parts that differ from the first and second embodiments will be described. In the first and second embodiments, the head unit 25 of the inkjet head 19 uniquely determines which actuator output terminals will not output print image data from. In contrast, in this third embodiment, this can be arbitrarily specified by the processor 22 of the inkjet printer 1.

[0083] Figure 8 shows an example of the configuration of the data processing unit 34 of the data transfer circuit 26 in the head control circuit 24 according to the third embodiment. In this third embodiment, the data processing unit 34 further includes a data storage unit 53 compared to the configuration in Figure 4.

[0084] In this third embodiment, if the data determination unit 48 determines that the analysis result of the input data is nozzle setting data, it transfers the nozzle setting data input from the data receiving circuit 33, i.e., from the processor 22 of the inkjet printer 1 via the head controller 20, to the data storage unit 53.

[0085] Figure 9 shows an example of the data format for nozzle setting data ND. Nozzle setting data ND consists of an 8-bit start bit followed by an 8-bit nozzle setting command indicating that the data is nozzle setting data, and then the setting data itself. In the example shown in Figure 9, the setting data includes nozzle numbers #-3 to #0 and nozzle numbers #321 to #324, which specify the nozzles before and after nozzle numbers #1 to #320. This is an example of causing the unused image data assignment unit 51 of the data transfer circuit 26-1 in the in-head control circuit 24 of the inkjet head 19-1 to generate the print image data ID 4-1 shown in Figure 5.

[0086] The data storage unit 53 stores the setting data as data entities in the nozzle setting data ND transferred from the data determination unit 48. For example, the data storage unit 53 can be configured as a register or RAM (Random Access Memory). The data storage unit 53 holds the setting data until new data is input, and inputs the held setting data to the unused image data assignment unit 51.

[0087] In this third embodiment, the unused image data assignment unit 51 is given the number of actuators, i.e., the number of nozzles, of the head unit 25 as known information.

[0088] The unused image data assignment unit 51 selects either the print image data input from the data determination unit 48 or the unused image data input from the fixed value storage unit 50 based on the nozzle numbers input from the unused nozzle number determination unit 49, the setting data stored in the data storage unit 53, and known information, and transfers the selected image data to the data determination unit 52 as print image data. Specifically, the unused image data assignment unit 51 determines the nozzle numbers that correspond to unnecessary nozzle numbers based on the setting data stored in the data storage unit 53. In the example shown in Figure 9, nozzle numbers #1 to #4 and nozzle numbers #325 to #328 are determined to be unnecessary nozzle numbers. Therefore, if nozzle numbers #1 to #4 are input from the unused nozzle number determination unit 49, the unused image data assignment unit 51 transfers the fixed values, which are unused image data input from the fixed value storage unit 50, to the data determination unit 52 as print image data. If nozzle numbers #5 to #324 are input from the unused nozzle number determination unit 49, the unused image data assignment unit 51 transfers the print image data input from the data determination unit 48 to the data determination unit 52 as print image data. Then, if nozzle numbers #325 to #324 are input from the unused nozzle number determination unit 49, the unused image data assignment unit 51 transfers the fixed value, which is unused image data input from the fixed value storage unit 50, to the data determination unit 52 as print image data. In this way, the unused image data assignment unit 51 assigns unused image data, which is a fixed value, to the print image data when the nozzle number matches an unused nozzle number.

[0089] Furthermore, when generating the print image data ID 8-1 shown in Figure 6 in the unused image data assignment unit 51 of the data transfer circuit 26-1 in the in-head control circuit 24 of the inkjet head 19-1, the nozzle setting data ND should be set to a predetermined setting value indicating that the unused nozzle number is an even nozzle number in the setting data as a data entity.

[0090] As described above, in the inkjet head 19 and the in-head control circuit 24 according to the third embodiment, the drive circuit 27 has a plurality of first actuator output terminals that output drive signals that contribute to driving a plurality of actuators of the head unit 25, and a plurality of second actuator output terminals that output drive signals that do not result in driving a plurality of actuators. The data processing unit 34 further includes a data determination unit 48 and a data storage unit 53 that function as setting units that set a plurality of second actuator output terminals based on settings from an external head controller 20, and the unused image data assignment unit 51 converts the first print image data into second print image data so that drive signals based on unused image data are output from the second actuator output terminals. Therefore, according to the inkjet head 19 and in-head control circuit 24 of the third embodiment, a second actuator output terminal can be set that outputs a drive signal from the outside that does not result in driving the actuator of the head unit 25.

[0091] [Fourth Embodiment] Next, a fourth embodiment will be described. Here, the same parts as in the first to third embodiments will be omitted from the description, and only the parts that differ from the first to third embodiments will be described. Figure 10 is a diagram showing an example of the configuration of the in-head control circuit 24 according to the fourth embodiment, and Figure 11 is a diagram showing an example of the configuration of the head controller 20 in the fourth embodiment. Note that Figure 10 shows the in-head control circuit 24 of the inkjet head 19-1.

[0092] As shown in Figure 10, the in-head control circuit 24 according to this fourth embodiment has a deserializer 54 prior to the data transfer circuits 26-1 and 26-2. In addition, in the in-head control circuit 24 according to this fourth embodiment, the reset signal output paths 42-1 and 42-2 from the drive circuits 27-1 and 27-2 are connected to the serial communication unit 55.

[0093] The deserializer 54 receives data transmitted from the head controller 20 via the inkjet head high-speed data transmission path DO1 through a data input path 56 connected to the inkjet head high-speed data transmission path DO1 from the head controller 20. As shown in Figure 11, in this embodiment, the high-speed data transmission circuit 47 of the head controller 20 combines the data that was transmitted using the inkjet head high-speed data transmission paths DOi1 and DOi2 in the first to third embodiments and transmits it using the inkjet head high-speed data transmission path DOi. Therefore, the deserializer 54 reconstructs this combined data into two data. The deserializer 54 then transmits one of the data to the data transfer circuit 26-1 via the data input path 32-11 and the other data to the data transfer circuit 26-2 via the data input path 32-12.

[0094] Furthermore, the serial communication unit 55 is a serial communication unit for serial communication (I2C, SPI, etc.). For example, the serial communication unit 55 is connected to two signal lines, the serial clock SCL and the serial data SDA, which constitute the serial communication path. The connection to the serial data SDA becomes the setting recognition signal output path. The serial clock SCL and serial data SDA that constitute the serial communication path are connected to the head controller 20. In the head controller 20, as shown in Figure 11, each serial clock SCL and each serial data SDA of each inkjet head 19 are commonly connected to the serial communication unit 55, and are also commonly connected to the control circuit 46 within the head controller. The serial communication unit 55 transmits the setting recognition signal from each drive circuit 27 to the head controller 20, along with a device address to identify the drive circuit 27. Therefore, the head controller 20 can easily determine which inkjet head 19 and which drive circuit 27 the setting recognition signal is from based on the device address.

[0095] As described above, the inkjet head 19 and the in-head control circuit 24 according to the fourth embodiment include a data input path 56 through which data such as drive circuit setting data and print image data are transmitted, and a deserializer 54 that separates the data transmitted through the data input path 56 into input data for a first data transfer circuit 26-1 that transmits input data to a first drive circuit 27-1, and input data for a second data transfer circuit 26-2 that transmits input data to a second drive circuit 27-2. Therefore, according to the inkjet head 19 and in-head control circuit 24 of the fourth embodiment, the number of connectors that receive data such as drive circuit setting data and print image data from the head controller 20 can also be reduced.

[0096] Furthermore, the inkjet head 19 and the in-head control circuit 24 according to the fourth embodiment include a serial communication unit 55 that serially communicates a setting recognition signal from a first drive circuit 27-1 transmitted through a setting recognition signal input path 43-1 and a setting recognition signal from a second drive circuit 27-2 transmitted through a setting recognition signal input path 43-2 to the head controller 20. Therefore, according to the inkjet head 19 and in-head control circuit 24 of the fourth embodiment, status signals indicating the status of each drive circuit 27 can be individually notified to the head controller 20.

[0097] Although the first to fourth embodiments have been described above, the embodiments are not limited to those described above.

[0098] For example, although each inkjet head 19 is assumed to have two head units 25, the number of head units 25 provided by each inkjet head 19 may be three or more. Conversely, the number of head units 25 provided by each inkjet head 19 may be one.

[0099] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of symbols]

[0100] 1…Inkjet printer, 2…Host PC, 3…Network, 11…Control unit, 12…Display, 13…Operation unit, 14…Communication interface, 15…Transport motor, 16…Motor drive circuit, 17…Pump, 18…Pump drive circuit, 19,19-1~19-n…Inkjet head, 20…Head controller, 21…Power supply, 22…Processor, 23…Memory, 24…In-head control circuit, 25,25-1,25-2…Head unit, 26,26-1,26-2…Data transfer circuit, 27,27-1,27-2…Drive circuit, 28…Clock receiving circuit, 29…Frequency conversion circuit, 30…Reset generation circuit, 31…Setting recognition signal generation unit, 32,32-11,32-12…Data input path, 33…Data receiving circuit, 34…Data processing unit 35...Data transmission circuit, 36...Command analysis unit, 37...Data counter, 38...Clock transmission circuit, 39...Clock signal input path, 40-1, 40-2...Clock signal output path, 41...Reset signal input path, 42-1, 42-2...Reset signal output path, 43-1, 43-2, 43-C...Setting recognition signal input path, 44...Pull-up resistor, 45...Setting recognition signal output path, 46...Head controller internal control circuit, 47...High-speed data transmission circuit, 48...Data determination unit, 49...Unused nozzle number determination unit, 50...Fixed value storage unit, 51...Unused image data assignment unit, 52...Data determination unit, 53...Data storage unit, 54...Deserializer, 55...Serial communication unit, 56...Data input path, CFG1~CFGn...Setting recognition signal reception path, D...Dummy data, DO1, DO11, DO12, DOi1, DOi2… High-speed data transmission paths for inkjet heads; ID1~ID7, ID3-1, ID3-2, ID4-1, ID4-2, ID7-1, ID7-2, ID8-1, ID8-2… Print image data.

Claims

1. First and second head units, each having multiple actuators for ejecting ink, The in-head control circuit that controls the first and second head units, Equipped with, The head-internal control circuit is, A first drive circuit that drives the first head unit according to first input data, A second drive circuit that drives the second head unit according to second input data, A first data transfer circuit that transfers the first input data received from an external source to the first drive circuit, A second data transfer circuit that transfers the second input data received from the external source to the second drive circuit, An input / output circuit that transmits the signal input from the external source to the first and second drive circuits, Equipped with, The aforementioned input / output circuit is A signal input path through which the signal input from the external source is transmitted, A first signal output path connected to the first drive circuit, A second signal output path connected to the second drive circuit, A generation unit generates a common control signal to control the first and second drive circuits based on the signal transmitted through the signal input path, and sends the generated common control signal to the first signal output path and the second signal output path. An inkjet head equipped with this feature.

2. The inkjet head according to claim 1, wherein the generation unit removes chattering of the control signal input from the outside and transmitted through the signal input path.

3. First and second head units, each having multiple actuators for ejecting ink, The in-head control circuit that controls the first and second head units, Equipped with, The head-internal control circuit is, A first drive circuit that drives the first head unit according to first input data, A second drive circuit that drives the second head unit according to second input data, A first data transfer circuit that transfers the first input data received from an external source to the first drive circuit, A second data transfer circuit that transfers the second input data received from the external source to the second drive circuit, An input / output circuit that transmits signals output from the first and second drive circuits to the outside, Equipped with, The aforementioned input / output circuit is A first signal input path connected to the first drive circuit, A second signal input path connected to the second drive circuit, The signal output path through which the signal to be output to the outside is transmitted, A generation unit generates a status signal indicating the state of the first and second drive circuits based on the signal from the first drive circuit transmitted through the first signal input path and the signal from the second drive circuit transmitted through the second signal input path, and sends the generated status signal to the signal output path. An inkjet head equipped with this feature.

4. The inkjet head according to claim 3, wherein the generation unit removes chattering of the state signal transmitted through the first and second signal input paths.

5. The inkjet head according to claim 3 or 4, wherein the generation unit generates the status signal and sends it to the signal output path when both the signal from the first drive circuit and the signal from the second drive circuit are obtained.

6. An in-head control circuit configured within an inkjet head comprising first and second head units, each having a plurality of actuators for ejecting ink, A first drive circuit that drives the first head unit according to first input data, A second drive circuit that drives the second head unit according to second input data, A first data transfer circuit that transfers first input data received from an external source to the first drive circuit, A second data transfer circuit that transfers the second input data received from the external source to the second drive circuit, An input / output circuit that transmits the signal input from the external source to the first and second drive circuits, Equipped with, The aforementioned input / output circuit is A signal input path through which the signal input from the external source is transmitted, A first signal output path connected to the first drive circuit, A second signal output path connected to the second drive circuit, A generation unit generates a common control signal to control the first and second drive circuits based on the signal transmitted through the signal input path, and sends the generated common control signal to the first signal output path and the second signal output path. A control circuit inside the head, equipped with the following features.

7. An in-head control circuit configured within an inkjet head comprising first and second head units, each having a plurality of actuators for ejecting ink, A first drive circuit that drives the first head unit according to first input data, A second drive circuit that drives the second head unit according to second input data, A first data transfer circuit that transfers the first input data received from an external source to the first drive circuit, A second data transfer circuit that transfers the second input data received from the external source to the second drive circuit, An input / output circuit that transmits signals output from the first and second drive circuits to the outside, Equipped with, The aforementioned input / output circuit is A first signal input path connected to the first drive circuit, A second signal input path connected to the second drive circuit, The signal output path through which the signal to be output to the outside is transmitted, A generation unit generates a status signal indicating the state of the first and second drive circuits based on the signal from the first drive circuit transmitted through the first signal input path and the signal from the second drive circuit transmitted through the second signal input path, and sends the generated status signal to the signal output path. A control circuit inside the head, equipped with the following features.

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