Liquid discharge device, signal sensing method and program

Abstract

To efficiently sense an input signal, in a head having a plurality of integrated circuits.SOLUTION: A liquid discharge device comprises drive ICs 251-253 and a control part 40. The drive ICs 251-253 are connected to a predetermined piezoelectric element group of a head 240 which has a nozzle for discharging ink and a piezoelectric element 242, so as to drive the piezoelectric element group. The drive ICs 251-253 have input sensing circuits 2514-2534. The input sensing circuits 2514-2534 are inputted with input signals such as a data signal Sin of ink discharge data and sense whether the inputted input signals are above a threshold or not. The drive ICs 251-253 are serially connected to one another through wiring of the data signal Sin. The control part 40 selects the drive IC from which a sensed result is read out from a sensing part, of the drive ICs 251-253. The input sensing circuits 2514-2534 are connected in parallel to the control part 40.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection device, a signal detection method, and a program. [Background technology]

[0002] Conventionally, inkjet recording devices have been known that use an inkjet head to eject ink from nozzles onto a recording medium to record an image. Inkjet recording devices typically use a large number of nozzles. If these nozzles fail to eject ink or if the ejection state between nozzles is uneven, the quality of the recording will deteriorate.

[0003] There are many different causes for ejection defects. If the cause cannot be analyzed, it can lead to unnecessary part replacement and increased downtime of the inkjet recording device. (1) Cable disconnection or data transfer error between the control board and inkjet head, (2) Control board, head failure, etc. (3) Clogging of nozzle holes, air bubbles, adhesion of dust, etc. There is.

[0004] Inkjet printing devices that detect the above (1) and (2) are known. For example, one inkjet printing device returns one print signal transferred to the print head to a host, compares the print signal with a loopback signal, and detects defects (see Patent Document 1). The print signal indicates whether or not to eject ink for each nozzle.

[0005] Also known is a recording device that has a voltage detection circuit that detects whether the power supply voltage supplied to the inkjet head is equal to or greater than a threshold voltage, thereby detecting an abnormality in the power supply system (see Patent Document 2). This recording device is equipped with a driver IC (Integrated Circuit) as an integrated circuit that has the voltage detection circuit. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 9-314834 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-99967 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the inkjet printing apparatus and printing apparatus disclosed in Patent Documents 1 and 2 can only detect signal defects in one driver IC corresponding to multiple nozzles. Multiple driver ICs are used per (inkjet) head. Ideally, detection would be performed on the signal lines of all driver ICs (integrated circuits). However, signal detection must be performed efficiently in limited time, such as between sheets of paper.

[0008] An object of the present invention is to efficiently detect an input signal in a head having a plurality of integrated circuits. [Means for solving the problem]

[0009] In order to solve the above problem, the liquid ejection device of the invention described in claim 1 comprises: a plurality of integrated circuits connected to predetermined groups of piezoelectric elements of a head having a plurality of nozzles and piezoelectric elements for ejecting ink, and for driving the groups of piezoelectric elements; each of the integrated circuits includes an input signal of ink ejection data, and has a detection unit that receives an input signal related to driving a corresponding piezoelectric element group, detects whether the input signal is equal to or greater than a threshold value, and generates a detection result; the plurality of integrated circuits are connected in series via wiring for signals of the ejection data; a control unit for selecting an integrated circuit from among the plurality of integrated circuits, the integrated circuit from which the detection result is read out from the detection unit; The liquid ejection device, wherein the plurality of detection units are connected in parallel to the control unit.

[0010] The invention described in claim 2 is the liquid ejection device described in claim 1, The control unit selects an integrated circuit from which to read the detection result in accordance with a detection possible time based on printing conditions.

[0011] The invention described in claim 3 is the liquid ejection device described in claim 1, The control unit selects a final stage integrated circuit from among the plurality of integrated circuits.

[0012] The invention described in claim 4 is the liquid ejection device described in claim 1, The control unit selects a first-stage integrated circuit from among the plurality of integrated circuits.

[0013] The invention described in claim 5 is the liquid ejection device described in claim 4, The control unit compares the input signal of the input source to the selected integrated circuit with the detection result read from the integrated circuit, and if the detection result of the first stage integrated circuit differs from the input signal of the input source, it notifies error information indicating a problem with the cable between the control board including the control unit and the head.

[0014] The invention described in claim 6 is the liquid ejection device described in claim 4, The control unit compares the input signal of the input source to the selected integrated circuit with the detection result read from the integrated circuit, and if the detection result of the integrated circuit in the first stage matches the input signal of the input source and the detection result of the selected integrated circuit other than the first stage differs from the input signal of the input source, it notifies error information indicating a malfunction of the head.

[0015] The invention described in claim 7 is the liquid ejection device described in claim 5 or 6, After notifying the error information, the control unit selects the multiple integrated circuits, reads out the additional detection results, compares the input signal of the input source to the selected integrated circuit with the additional detection results read out from the integrated circuit, and clears the error information if the additional detection results match the input signal of the input source.

[0016] The invention described in claim 8 is the liquid ejection device described in claim 7, When the additional detection result of the integrated circuit at the first stage differs from the input signal of the input source, the control unit notifies error information indicating a malfunction of a control board including the control unit.

[0017] The invention described in claim 9 is the liquid ejection device described in claim 1, The detection unit detects the logic of the first and last stages of a shift register that stores the discharge data signal.

[0018] The liquid ejection device of the invention described in claim 10 comprises: a plurality of integrated circuits connected to predetermined groups of piezoelectric elements of a head having a plurality of nozzles and piezoelectric elements for ejecting ink, and for driving the groups of piezoelectric elements; Each of the integrated circuits has a detection unit that receives an input signal related to driving a corresponding piezoelectric element group, detects whether the input signal is equal to or greater than a threshold value, and generates a detection result; the plurality of integrated circuits are connected by unicursal wiring of the input signals, The control unit selects an integrated circuit from among the plurality of integrated circuits from which the detection result is read out from the detection unit.

[0019] The invention described in claim 11 is the liquid ejection device described in claim 10, The control unit selects an integrated circuit from which to read the detection result in accordance with a detection possible time based on printing conditions.

[0020] The invention described in claim 12 is the liquid ejection device described in claim 10, The control unit selects a final stage integrated circuit from among the plurality of integrated circuits.

[0021] The invention described in claim 13 is the liquid ejection device described in claim 10, The control unit selects a first-stage integrated circuit from among the plurality of integrated circuits.

[0022] The invention described in claim 14 is a plurality of integrated circuits connected to predetermined groups of piezoelectric elements of a head having a plurality of nozzles and piezoelectric elements for ejecting ink, and for driving the groups of piezoelectric elements; each of the integrated circuits includes an input signal of ink ejection data, and has a detection unit that receives an input signal related to driving a corresponding piezoelectric element group, detects whether the input signal is equal to or greater than a threshold value, and generates a detection result; a signal detection method for a liquid ejection device in which the plurality of integrated circuits are connected in series via wiring for input signals of the ejection data, a control step of selecting an integrated circuit from the plurality of integrated circuits by a control unit, the integrated circuit being used to read out a detection result from the detection unit; The plurality of detectors are connected in parallel to the controller.

[0023] The invention described in claim 15 is a plurality of integrated circuits connected to predetermined groups of piezoelectric elements of a head having a plurality of nozzles and piezoelectric elements for ejecting ink, and for driving the groups of piezoelectric elements; Each of the integrated circuits has a detection unit that receives an input signal related to driving a corresponding piezoelectric element group, detects whether the input signal is equal to or greater than a threshold value, and generates a detection result; a signal detection method for a liquid ejection device, wherein the plurality of integrated circuits are connected by unicursal wiring of the input signal, The control step includes a control step in which the control unit selects an integrated circuit from among the plurality of integrated circuits from which the detection result is read out from the detection unit.

[0024] The program of the invention described in claim 16 is a plurality of integrated circuits connected to predetermined groups of piezoelectric elements of a head having a plurality of nozzles and piezoelectric elements for ejecting ink, and for driving the groups of piezoelectric elements; each of the integrated circuits includes an input signal of ink ejection data, and has a detection unit that receives an input signal related to driving a corresponding piezoelectric element group, detects whether the input signal is equal to or greater than a threshold value, and generates a detection result; The plurality of integrated circuits are connected in series via wiring for input signals of the ejection data to a computer of the liquid ejection device, a control unit that selects an integrated circuit from the plurality of integrated circuits to read out a detection result from the detection unit; It functions as The plurality of detectors are connected in parallel to the controller.

[0025] The program of the invention described in claim 17 is a plurality of integrated circuits connected to predetermined groups of piezoelectric elements of a head having a plurality of nozzles and piezoelectric elements for ejecting ink, and for driving the groups of piezoelectric elements; Each of the integrated circuits has a detection unit that receives an input signal related to driving a corresponding piezoelectric element group, detects whether the input signal is equal to or greater than a threshold value, and generates a detection result; The plurality of integrated circuits are connected to a computer of the liquid ejection device by a single-stroke wiring of the wiring of the input signal, a control unit that selects an integrated circuit from the plurality of integrated circuits to read out a detection result from the detection unit; Function as. [Effects of the Invention]

[0026] According to the present invention, input signals can be detected efficiently in a head having a plurality of integrated circuits. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a schematic diagram illustrating the configuration of an inkjet recording apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram schematically illustrating a nozzle surface of a head unit. [Figure 3] FIG. 2 is a block diagram illustrating a functional configuration of the inkjet printing apparatus. [Figure 4] FIG. 2 is a block diagram showing the circuit configuration of a piezoelectric element of a head and a head driving unit. [Figure 5] 10 is a flowchart illustrating a printing process. [Figure 6]6 is a flowchart showing the continuation of the printing process in FIG. 5. [Figure 7] FIG. 10 is a diagram illustrating a specific example of printing processing. [Figure 8] FIG. 10 is a diagram showing a wiring board according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0028] The advantages and features provided by one or more embodiments of the present invention will be more fully understood from the following detailed description and the accompanying drawings. However, these drawings are for illustrative purposes only and are not intended to define the limits of the present invention. Hereinafter, embodiments and modifications of the present invention will be described with reference to the drawings. However, the scope of the present invention is not limited to the disclosed embodiments and modifications.

[0029] (Embodiment) An embodiment of the present invention will be described with reference to Figs. 1 to 7. First, the configuration of the device of this embodiment will be described with reference to Figs. 1 to 4. Fig. 1 is a schematic diagram showing the configuration of an inkjet recording device 1 of this embodiment. Fig. 2 is a diagram schematically showing a nozzle surface 2412 of a head unit 24K. Fig. 3 is a block diagram showing the functional configuration of the inkjet recording device 1. Fig. 4 is a block diagram showing the circuit configuration of a piezoelectric element 242 of a head 240 and a head driving unit 25.

[0030] 1, an inkjet recording apparatus 1 serving as a liquid ejection apparatus includes a paper feed unit 10, an image forming unit 20, and a paper discharge unit 30. As shown in FIGS. 1 and 2, the conveyance direction of the recording medium is defined as conveyance direction x, and the width direction of the recording medium perpendicular to the conveyance direction x is defined as width direction y.

[0031] The paper feed unit 10 has a paper feed tray 11 and a medium supply unit 12. The image forming unit 20 has a transport unit 21, a delivery unit 22, a paper heating unit 23, a head unit 24, a fixing unit 26, and a delivery unit 27. The paper discharge unit 30 has a paper discharge tray 31.

[0032] The inkjet recording device 1 conveys the recording medium 2 stored in the paper feed unit 10 to the image forming unit 20 under the control of the control unit 40 (FIG. 3). The inkjet recording device 1 forms an image by ejecting ink onto the recording medium 2 in the image forming unit 20. The inkjet recording device 1 conveys the recording medium 2 on which the image has been formed to the paper discharge unit 30 and discharges it.

[0033] In this example, the recording medium 2 is paper, particularly plain paper, but is not limited to this. The recording medium 2 may be any medium on whose surface the ink that has landed can be fixed. The recording medium 2 may be, for example, coated paper, fabric, or sheet-like resin.

[0034] The paper feed tray 11 stores the recording medium 2. The medium supply unit 12 transports and supplies the recording medium 2 from the paper feed tray 11 to the image forming unit 20. The medium supply unit 12 includes, for example, a circular belt supported by two rollers on the inside. The medium supply unit 12 rotates the two rollers with the recording medium 2 placed on the belt to transport the recording medium 2 from the paper feed tray 11 to the image forming unit 20.

[0035] The transport unit 21 holds the recording medium 2 placed on a transport surface (mounting surface) 2111 of a cylindrical transport drum 211. The transport drum 211 rotates and moves around a rotation axis (cylindrical axis) extending in the width direction y. As a result, the transport drum 211 transports the recording medium 2 placed on the transport surface 2111 in the transport direction x.

[0036] The transport drum 211 has claws and an air intake section (not shown) for holding the recording medium 2 on the transport surface 2111. The edges of the recording medium 2 are pressed by the claws. The recording medium 2 is also drawn to the transport surface 2111 by the air intake section and held thereon. The transport section 21 is connected to a transport drum motor for rotating the transport drum 211. The transport drum 211 rotates by an angle proportional to the amount of rotation of the transport drum motor.

[0037] The transfer unit 22 transfers the recording medium 2 transported by the medium supply unit 12 to the transport unit 21. The transfer unit 22 is provided at a position between the medium supply unit 12 and the transport unit 21. The transfer unit 22 has a swing arm unit 221 and a transfer drum 222. The swing arm unit 221 holds one end of the recording medium 2 transported from the medium supply unit 12 and picks it up. The transfer drum 222 transfers the picked-up recording medium 2 to the transport unit 21.

[0038] The paper heating unit 23 is provided between the position where the delivery drum 222 is disposed and the position where the head unit 24 is disposed. The paper heating unit 23 heats the recording medium 2 conveyed by the conveyance unit 21 so that the temperature of the recording medium 2 falls within a predetermined temperature range. The paper heating unit 23 has, for example, an infrared heater. The paper heating unit 23 applies electricity to the infrared heater to generate heat.

[0039] As shown in Fig. 2, the head unit 24 includes a plurality of heads 240 mounted on a carriage 243. The head 240 is an inkjet head that includes a plurality of nozzle openings 2411 of nozzles 241 (Fig. 3) on a nozzle surface 2412. The head unit 24 ejects ink from the plurality of nozzle openings 2411 at appropriate timing onto the recording medium 2 to form an image. The head unit 24 is disposed such that the nozzle surface 2412 and the transport surface 2111 are spaced apart by a predetermined distance.

[0040] Four head units 24 are arranged in the inkjet recording device 1. The four head units 24 correspond to four colors of ink: yellow (Y), magenta (M), cyan (C), and black (K). These four head units 24 are referred to as head units 24Y, 24M, 24C, and 24K. The head units 24Y, 24M, 24C, and 24K are arranged at predetermined intervals from the upstream side in the transport direction in the order of Y, M, C, and K.

[0041] The ink ejected from the nozzle opening 2411 is ink that undergoes sol-gel phase transition. Sol-gel phase transition ink contains a gelling agent and changes phase between gel and sol depending on the temperature. Sol-gel phase transition ink has the property of hardening when irradiated with energy rays such as ultraviolet rays. The ink contains a pigment.

[0042] The head unit 24 includes an ink heating section (not shown). The ink heating section operates under the control of the control section 40. The ink heating section heats an ink storage section (not shown) to a predetermined reference temperature at which the ink stored therein becomes a sol. The ink heated by the ink heating section is ejected from the nozzle openings 2411. The ink that has landed on the recording medium 2 quickly becomes gel-like as it cools naturally, and solidifies on the recording medium 2.

[0043] The ink heating unit also includes a temperature measurement unit (not shown). The ink heating unit's heating operation is switched by the control unit 40, and maintains the ink temperature so that a predetermined reference temperature is detected by the temperature measurement unit. The heating operation of the ink heating unit can be switched by a simple on / off operation or by step-like switching in multiple stages. The heating operation of the ink heating unit can also be switched by PWM (Pulse Width Modulation) control using high-frequency on / off operation.

[0044] 1 illustrates an example in which the inkjet recording apparatus 1 is configured to include four head units 24, but this is not limiting. The number of head units 24 arranged in one inkjet recording apparatus 1 may be three or less, or five or more. Furthermore, the configuration is not limited to one head unit 24 arranged per ink color, and multiple head units 24 may be arranged. Furthermore, although multiple head units 24 are arranged in the transport direction x in FIG. 1, multiple head units 24 may also be arranged in the width direction y.

[0045] The fixing unit 26 has a light-emitting unit arranged across the width of the conveying unit 21 in the width direction y. The light-emitting unit emits energy rays such as ultraviolet rays to the recording medium 2 placed on the conveying unit 21. The fixing unit 26 cures and fixes the gel ink ejected onto the recording medium 2 by emitting the energy rays. The light-emitting unit is arranged facing the conveying surface 2111 between the position where the head unit 24 is arranged and the position where the delivery unit 27 is arranged.

[0046] The delivery unit 27 has a transfer drum 271 and a belt loop 272. The transfer drum 271 is cylindrical and transfers the recording medium 2 from the conveyance unit 21 to the belt loop 272. The belt loop 272 has a ring-shaped belt supported on the inside by two rollers. The delivery unit 27 sends the recording medium 2 transferred from the conveyance unit 21 to the transfer drum 271 to the paper discharge unit 30 by the belt loop 272.

[0047] In the paper discharge unit 30, the recording medium 2 sent from the image forming unit 20 by the delivery unit 27 is placed on a plate-shaped paper discharge tray 31.

[0048] The head unit 24K will be described with reference to Fig. 2. Note that the head units 24C, 24M, and 24Y have the same configuration as the head unit 24K, and therefore descriptions thereof will be omitted.

[0049] The head unit 24K is provided with a plurality of (e.g., 16) heads 240, each having a plurality of nozzle openings 2411 arranged at a predetermined interval (nozzle spacing) on ​​its bottom surface. The number of nozzles 241 (nozzle openings 2411) in each head 240 is, for example, 800, and the number of piezoelectric elements 242 (FIG. 3) is the same. Two heads 240 are paired, and the nozzle openings 2411 of each head 240 are arranged alternately in the width direction. The pairs of heads 240 are further arranged in a staggered pattern, thereby forming a line head in which the nozzle openings 2411 are arranged at uniform intervals in the width direction across the above-mentioned recordable width.

[0050] The inkjet recording device 1 forms an image on the recording medium 2 using a one-pass method with the head unit 24. In the one-pass method, the nozzle surface is fixed facing the transport surface during the image formation operation, and ink is ejected sequentially at predetermined intervals to different positions in the transport direction as the recording medium 2 is transported. The recording resolution in the transport direction x is determined by the drive frequency of ink ejection from the nozzle openings 2411, the transport speed, etc.

[0051] 3, the internal functional configuration of the inkjet recording apparatus 1 will be described. The inkjet recording apparatus 1 includes an image forming unit 20, a control unit 40, a storage unit 50, a transport drive unit 61, a head unit moving unit 62, a cleaning unit 63, an operation display unit 70, and a communication unit 80. The various units of the inkjet recording apparatus 1 are connected via a bus 90.

[0052] The control unit 40 is a system control unit that controls the overall operation of the inkjet recording apparatus 1. The control unit 40 is mounted on a control board (not shown). The control unit 40 includes a CPU (Central Processing Unit), RAM (Random Access Memory), etc. The CPU performs various arithmetic processing and executes various commands of a control program related to control operations. The control operations include image processing and printing processing (described below). Image processing is image processing of image data of an image to be recorded. Printing processing is processing that controls the operations of the paper feed unit 10, image forming unit 20, and paper discharge unit 30 according to the image data to be recorded, thereby forming an image on the recording medium 2. The RAM provides working memory space for the CPU and temporarily stores various data and programs. The RAM may include a writable and updatable non-volatile memory such as flash memory.

[0053] The storage unit 50 stores various control programs, setting data, image data to be recorded, etc. The various control programs and setting data are preferably stored in a nonvolatile memory such as a flash memory or an HDD (Hard Disk Drive). Data related to the image to be recorded is preferably stored in a volatile memory such as a DRAM capable of large-capacity, high-speed processing. The storage unit 50 includes these nonvolatile memories and DRAM. The control programs include a printing program for executing the printing process described below. The image data to be recorded includes, for example, image data received from a PC (Personal Computer) 3 as an external device via the communication unit 80. The storage unit 50 also stores error information related to the control board including the control unit 40, the head 240, and the cables between them.

[0054] The image forming unit 20, under the control of the control unit 40, ejects YMCK ink onto the recording medium 2 supplied by the paper feed unit 10 to form an image. Each head 240 of each head unit 24 has a plurality of nozzles 241, a plurality of piezoelectric elements 242, and a plurality of head driving units 25. Each nozzle 241 ejects ink. Each piezoelectric element 242 is connected to one of the plurality of arranged nozzles 241. Each piezoelectric element 242 deforms the middle of the ink flow path (pressure chamber) that supplies ink to each nozzle 241, thereby applying a pressure change to the ink. The piezoelectric elements 242 are made of a well-known material such as lead zirconate titanate (PZT), and the deformation mode is, for example, a shear mode, but is not particularly limited to this.

[0055] Each head driving unit 25 supplies a driving signal to the piezoelectric element 242 of each head 240 at an appropriate timing according to the image data, causing the piezoelectric element 242 to deform. As a result, the head driving unit 25 ejects an amount of ink according to the pixel value of the image data from the nozzle opening 2411. Each head driving unit 25 also has a configuration for detecting signals input from a control board including the control unit 40, and inspecting the head 240 for broken wiring for each signal or malfunction of a component. This configuration will be described later.

[0056] The transport drive unit 61 supplies a drive signal to the transport drum motor of the transport drum 211 under the control of the control unit 40. As a result, the transport drive unit 61 rotates the transport drum 211 at a predetermined speed and timing. Also, under the control of the control unit 40, the transport drive unit 61 supplies a drive signal to motors for operating the medium supply unit 12, the delivery unit 22, and the delivery unit 27. As a result, the transport drive unit 61 supplies the recording medium 2 to the transport unit 21 and ejects it from the transport unit 21.

[0057] The head unit moving section 62 has a motor and brake of a movement mechanism for moving the head unit 24 in the width direction y. The head unit moving section 62 moves the head unit 24 from the normal image forming position to a maintenance position in the width direction y during maintenance time in accordance with the control of the control section 40. After maintenance is completed, the head unit moving section 62 returns the head unit 24 to the original image forming position.

[0058] The cleaning unit 63 has a wiping cloth, a presser member, an unwinding roller, and a winding roller (all not shown). The cleaning unit 63 cleans the nozzle surface 2412 of the head 240 that has been moved to the maintenance position under the control of the control unit 40. The cleaning unit 63 wipes the nozzle surface 2412 with a wiping cloth, and removes and cleans foreign matter and ink adhering to the nozzle surface 2412 and the inside of the nozzle openings 2411.

[0059] The operation display unit 70 has an operation unit and a display unit. The operation unit accepts input operations from the outside, such as from a user, and outputs the accepted operation details to the control unit 40 as an electrical signal. The display unit displays display information related to the inkjet recording apparatus 1 and menus related to user input operations, based on the control of the control unit 40. The display unit is, for example, a liquid crystal display or an EL (Electro-Luminescent) display. The operation display unit 70 accepts input operations from the user as an operation unit by providing a touch sensor superimposed on the display unit and operating it as a touch panel.

[0060] The communication unit 80 controls the transmission and reception of data between the inkjet recording apparatus 1 and external devices in accordance with a predetermined communication standard. The communication unit 80 includes, for example, a network card that controls a TCP / IP (Transmission Control Protocol / Internet Protocol) connection via a LAN (Local Area Network). The external device that communicates with the inkjet recording apparatus 1 via the communication unit 80 is a PC 3. However, the external device is not limited to a PC, and may be other devices such as a print server or various mobile terminals.

[0061] Referring to FIG. 4, the circuit configuration of the piezoelectric elements 242 and head driver 25 in the head 240 will be described. One head 240 has a piezoelectric element 242 and a head driver 25. The head driver 25 has driver ICs 251, 252, and 253 as integrated circuits. The piezoelectric elements 242 in one head 240 are composed of, for example, 800 piezoelectric elements (actuators). The number of driver ICs in one head 240 is set based on the number of piezoelectric elements per wafer, the density of nozzles, and the tolerance requirements of the wiring board on which they are mounted. The wiring board is composed of, for example, an FPC (Flexible Printed Circuit). However, the number of driver ICs in one head 240 is not limited to three. In this way, the piezoelectric elements 242 in one head 240 are connected to the driver ICs 251, 252, and 253, each of which is configured with a plurality of piezoelectric elements to be controlled.

[0062] The driving ICs 251 to 253 are mounted on a wiring board (not shown). The driving IC 251 has a shift register 2511, a latch circuit 2512, an output circuit 2513, an input detection circuit 2514, and an address setting unit 2515. The driving IC 252 has a shift register 2521, a latch circuit 2522, an output circuit 2523, an input detection circuit 2524, and an address setting unit 2525. The driving IC 253 has a shift register 2531, a latch circuit 2532, an output circuit 2533, an input detection circuit 2534, and an address setting unit 2535. The input detection circuits 2514 to 2534 function as detection units.

[0063] The shift register 2511 receives a clock signal DCLK from the control board and a data signal Sin from the control unit 40. The clock signal DCLK is a digital clock signal that serves as a reference for controlling the shift register. The data signal Sin is a logical signal of ejection data that indicates whether or not to eject ink for each nozzle (piezoelectric element). However, the data signal Sin may also be, for example, 3-bit ejection data that controls the amount of ink ejected from each nozzle. The shift register 2511 stores and shifts the data signal Sin in response to the clock signal DCLK, and outputs it to the latch circuit 2512 in accordance with the piezoelectric element of each nozzle to be controlled.

[0064] Furthermore, the data signal Sin is a signal common to the driving ICs 251, 252, and 253. For this reason, the shift register 2511 outputs the data signal Sin to the shift register 2521 of the driving IC 252. The shift register 2521 receives the data signal Sin as input. The shift register 2521 stores and shifts the data signal Sin in accordance with the clock signal DCLK, and outputs it to the latch circuit 2522 corresponding to the piezoelectric element of each nozzle to be controlled. The shift register 2521 outputs it to the shift register 2531 of the driving IC 253. The shift register 2531 receives the data signal Sin as input. The shift register 2531 stores and shifts the data signal Sin in accordance with the clock signal DCLK, and outputs it to the latch circuit 2532 corresponding to the piezoelectric element of each nozzle to be controlled.

[0065] In this way, along the flow of the data signal Sin, the most upstream driver IC 251 is the first stage driver IC, and similarly, the most downstream driver IC 253 is the last stage driver IC.

[0066] The latch circuit 2512 receives a latch signal LAT from the control unit 40 and a data signal from the shift register 2511. The latch signal LAT is a logic signal that indicates the timing of latching (acquiring and holding) the data signal Sin. In response to the latch signal LAT, the latch circuit 2512 acquires the data signal Sin corresponding to the piezoelectric element of the nozzle to be controlled and outputs and holds the data signal Sin to the output circuit 2513.

[0067] The output circuit 2513 receives a voltage VH from a power supply (not shown) of the control board, a signal PLSTM from the control unit 40, and a data signal from the latch circuit 2512. The voltage VH is a power supply voltage. The signal PLSTM is a signal that indicates the application time of a voltage corresponding to each piezoelectric element of the piezoelectric element 242. The output circuit 2513 is a circuit that applies the voltage VH to each piezoelectric element of the piezoelectric element 242 that is the control target for the application time during the period of the signal PLSTM in response to the data signal. By applying the voltage VH, the output circuit 2513 causes ink to be ejected from the nozzles of each piezoelectric element that is the control target.

[0068] The input detection circuit 2514 receives branched signals from the latch signal LAT, signal PLSTM, and voltage VH input to the drive IC 251 from the control board. The input detection circuit 2514 receives a first output signal from the output terminal of the first stage of the shift register 2511 to the latch circuit 2512 and a second output signal from the output terminal of the last stage. Thus, the input detection circuit 2514 does not need to detect the output signals from all output terminals of the shift register 2511, thereby reducing the processing load and preventing an increase in the size of the detection circuit. The input detection circuit 2514 compares the input latch signal LAT, signal PLSTM, voltage VH, and first and second output signals with their respective reference voltage thresholds. The input detection circuit 2514 detects whether each input signal is equal to or greater than a threshold and generates a detection result. For example, the input detection circuit 2514 compares the voltage of each input signal with a predetermined threshold voltage during a period when the logic of each signal other than voltage VH is high. The input detection circuit 2514 generates a detection result indicating whether each input signal is equal to or greater than a threshold. The input detection circuit 2514 also compares the input voltage VH with a threshold that is a predetermined voltage set in advance or a threshold corresponding to a voltage value input from the control unit 40. The input detection circuit 2514 generates a detection result indicating whether the input voltage VH is equal to or greater than the threshold. The detection result for each signal is a logical value indicating whether the signal is equal to or greater than a threshold.

[0069] The address setting unit 2515 is a circuit element in which a unique address of the driving IC 251 is set for each driving IC. The address setting unit 2515 has, for example, a plurality of external terminals. The address setting unit 2515 sets an address based on the pattern of whether or not each external terminal is connected to the mounting substrate. The control unit 40 can communicate with the specified input detection circuit by specifying the address set by the address setting unit 2515.

[0070] Latch circuit 2522 of driving IC 252 and latch circuit 2532 of driving IC 253 operate in the same manner as latch circuit 2512 of driving IC 251. Output circuit 2523 and output circuit 2533 operate in the same manner as output circuit 2513. Input detection circuit 2524 and input detection circuit 2534 operate in the same manner as input detection circuit 2514. Address setting unit 2525 and address setting unit 2535 operate in the same manner as address setting unit 2515. The addresses of driving ICs 251, 252, and 253 are distinguishable from one another.

[0071] In the head 240, the driving ICs 251 to 253 (shift registers 2511 to 2531) are connected in series via wiring for the data signal Sin among the various signals. Similarly, the input detection circuits 2514 to 2534 of the driving ICs 251 to 253 are connected in parallel to the control unit 40.

[0072] Next, the operation of the inkjet recording apparatus 1 will be described with reference to Fig. 5 to Fig. 7. Fig. 5 is a flowchart showing the printing process. Fig. 6 is a flowchart showing a continuation of the printing process of Fig. 5. Fig. 7 is a diagram showing a specific example of the printing process.

[0073] The printing process is a process of forming an image on the recording medium 2, detecting each signal input to the head 240, and inspecting for disconnections and malfunctions of components. In the inkjet recording device 1, for example, power is turned on by the user turning on the power switch. The control unit 40 executes the printing process in accordance with the printing program stored in the storage unit 50.

[0074] 5, first, the control unit 40 determines whether or not head connection error information is stored in the storage unit 50 (step S11). The head connection error information is head replacement error information or cable replacement error information. The head replacement error information indicates a malfunction due to an internal wire break or malfunction in the head 240, and is error information that prompts replacement of the head 240. The cable replacement error information indicates a malfunction due to a wire break in the cable between the head 240 and the control board, and is error information that prompts replacement of the cable.

[0075] If no head connection error information is stored (step S11; YES), the process proceeds to step S12. The control unit 40 inputs each signal of the test pattern to all the driving ICs (step S12). In step S12, the control unit 40 causes the input detection circuit of each driving IC to detect each signal input to each driving IC and acquires the detection results. The control unit 40 compares the detection results of each signal with the input value of each signal of the test pattern at the input source to each driving IC. Based on the comparison results, the control unit 40 determines whether the detection results of each signal of the test pattern in all the driving ICs match the input value of the input source and whether the detection results are OK (normal).

[0076] If the detection results for all the driving ICs are OK (step S12; YES), the control unit 40 receives the printing conditions from the PC 3 via the communication unit 80 (step S13). The printing conditions include the ink ejection drive frequency, the ejection data pattern, and whether or not maintenance is required and the time required. The printing conditions may be associated with, for example, the operating mode of the inkjet recording device 1. The user inputs image data to be printed and the printing conditions or operating mode thereof into the PC 3, and the printing conditions corresponding to the printing conditions or operating mode are transmitted to the inkjet recording device 1. The control unit 40 calculates the non-ink ejection time (detectable time) for each printing sequence from the printing conditions and selects the driving ICs from which the detection results are to be acquired (step S14). The non-ink ejection time includes the time between sheets of the recording medium 2, the maintenance time if maintenance is required, and the printing pause period for maintaining the temperature of the head 240 and the ink.

[0077] FIG. 7 shows a specific example of printing processing. In step S14, for example, as shown in FIG. 7, when the non-ink ejection time is extra long, which is the longest range, all driving ICs are selected. When the non-ink ejection time is extra long, for example, after the initial startup or when maintenance is being performed. Note that in step S12, after startup, all driving ICs detect and determine each signal. When the non-ink ejection time is large, which is the next longest range, the driving ICs 251 and 253 in the first and last stages are selected. When the non-ink ejection time is long, for example, between sheets, the driving frequency for ink ejection is low.

[0078] When the non-ink ejection time is in the medium range, which is the next longest range, the driving IC 253 in the final stage is selected. When the non-ink ejection time is medium, for example, when the ink ejection drive frequency is medium between sheets of paper. When the non-ink ejection time is in the shortest range, the driving IC 251 in the first stage is selected. When the non-ink ejection time is short, for example, when the ink ejection drive frequency is high between sheets of paper.

[0079] 5, the control unit 40 receives image data to be printed from the PC 3 via the communication unit 80 and stores it in the storage unit 50 (step S15). In step S15, the control unit 40 controls the paper feed unit 10, the image forming unit 20, the paper discharge unit 30, and the transport drive unit 61 according to the printing conditions of step S13 to print the received image data. During maintenance time, the head unit moving unit 62 and the cleaning unit 63 are also controlled to perform maintenance.

[0080] The control unit 40 determines whether the current time is the paper interval time of the current sequence based on the paper interval time calculated in step S14 (step S16). In step S16, if it is the paper interval time, the control unit 40 inputs each signal of the test pattern to the input detection circuit of the selected drive IC. The control unit 40 causes the input detection circuit of the selected drive IC to detect each signal input to the selected drive IC and acquires the detection results. The control unit 40 compares the detection results of each signal with the input value of each signal of the test pattern at the input source to each drive IC. Depending on the comparison result, the control unit 40 determines whether the detection results of each signal of the test pattern in the selected drive IC match the input value of the input source and the detection result is OK.

[0081] If the detection result of the selected driving IC is OK during the paper interval of the current sequence, or if it is not the paper interval (step S16; YES), the process proceeds to step S17. The control unit 40 determines whether the current time is the maintenance time of the current sequence based on the presence or absence of maintenance and the maintenance time calculated in step S13 (step S17). In step S17, if it is the maintenance time, the control unit 40 controls the head unit moving unit 62 and the cleaning unit 63 to perform maintenance of the head unit. Furthermore, the control unit 40 inputs each signal of the test pattern to the input detection circuit of the selected driving IC. The control unit 40 causes the input detection circuit of the selected driving IC to detect each signal input to the selected driving IC and acquires the detection results. The control unit 40 compares the detection results of each signal with the input value of each signal of the test pattern input source to each driving IC. Based on the comparison result, the control unit 40 determines whether the detection result of each signal of the test pattern in the selected driving IC matches the input value of the input source and whether the detection result is OK.

[0082] If the detection result of the selected driving IC is OK at the maintenance time of the current sequence, or if it is not the maintenance time (step S17; YES), the process proceeds to step S18. The control unit 40 determines whether or not to end printing (step S18). If printing is not to end (step S18; NO), the process proceeds to step S15.

[0083] If printing is to be ended (step S18; YES), the process proceeds to step S19. The control unit 40 determines whether or not to end printing without changing the printing conditions based on whether or not an instruction to change the printing conditions has been received from the PC 3 via the communication unit 80 (step S19). Information on changing the printing conditions is input by the user on the PC 3, for example, and sent to the inkjet recording apparatus 1. If the printing conditions are to be changed and printing is not to be ended (step S19; NO), the process proceeds to step S13. If printing is to be ended without changing the printing conditions (step S19; YES), the control unit 40 stops the operation of the inkjet recording apparatus 1 and ends the printing process.

[0084] If the detection results of all the drive ICs are not OK (step S12; NO), the process proceeds to step S20. If the detection result of the selected drive IC during the paper interval of the current sequence is not OK (step S16; NO), the process proceeds to step S20. If the detection result of the selected drive IC during the maintenance time of the current sequence is not OK (step S17; NO), the process proceeds to step S20.

[0085] The control unit 40 determines whether an error (detection result and input value of the input source differ) has occurred in the first-stage driving IC 251 in step S12, S16, or S17 (step S20). If an error has occurred in the first-stage driving IC 251 (step S20; YES), the process proceeds to step S21. In step S21, the control unit 40 generates cable replacement error information and transmits the cable replacement error information to the PC 3 via the communication unit 80 (step S21). In response to step S21, the control unit (not shown) of the PC 3 receives the cable replacement error information from the inkjet recording apparatus 1 and displays it on the display unit (not shown) to notify the user. The user or service technician replaces the cable between the head 240 and the control board that corresponds to the displayed cable replacement error information. The control unit 40 stores the cable replacement error information in the storage unit 50 (step S22). The control unit 40 stops the operation of the inkjet recording apparatus 1 and ends the printing process.

[0086] If no error has occurred in the first-stage driving IC 251 (step S20; NO), the process proceeds to step S23. In step S23, the control unit 40 generates head replacement error information and transmits the head replacement error information to PC3 via the communication unit 80 (step S23). This is because no error has occurred in the first-stage driving IC 251, and at least no break has occurred in the cable. In response to step S24, the control unit of PC3 receives the head replacement error information from the inkjet recording device 1 and displays it on the display unit to notify the user. The user or service technician replaces the head 240 corresponding to the displayed head replacement error information. The control unit 40 stores the head replacement error information in the memory unit 50 (step S24). The control unit 40 stops the operation of the inkjet recording device 1 and ends the printing process.

[0087] 6, if head connection error information is stored (step S11; YES), the process proceeds to step S31. That is, this is the case when printing processing is executed again after step S22 or S24 is executed. The control unit 40 determines whether head replacement error information is stored in the storage unit 50 (step S31). If head replacement error information is stored (step S31; YES), the process proceeds to step S32. Step S32 is the same as step S12.

[0088] If the detection results of all the drive ICs are OK (step S32; YES), the control unit 40 clears (deletes) the head replacement error information from the storage unit 50 (step S33). The process proceeds to step S13. If the detection results of all the drive ICs are not OK (step S32; NO), the control unit 40 generates control board replacement error information and sends the control board replacement error information to PC3 via the communication unit 80 (step S34). The control board replacement error information is error information that prompts replacement of the control board due to an internal disconnection or failure of the control board. This is because the error occurs even after replacing the head 240. In response to step S34, the control unit of PC3 receives the control board replacement error information from the inkjet recording apparatus 1 and displays it on the display unit. The user or service technician replaces the control board corresponding to the displayed control board replacement error information. The control unit 40 stops the operation of the inkjet recording apparatus 1 and ends the printing process.

[0089] If head replacement error information is not stored (step S31; NO), the process proceeds to step S35. In this case, cable replacement error information is stored in the storage unit 50. Step S35 is the same as step S12.

[0090] If the detection results of all the driving ICs are OK (step S35; YES), the control unit 40 clears the cable replacement error information from the storage unit 50 (step S36). The process proceeds to step S13. If the detection results of all the driving ICs are not OK (step S35; NO), the control unit 40 determines whether an error has occurred in the driving IC 251 in the first stage in step S35 (step S37). If an error has occurred in the driving IC 251 in the first stage (step S37; YES), the process proceeds to step S34.

[0091] If no error has occurred in the first-stage driving IC 251 (step S37; NO), the process proceeds to steps S38, S39, and S40 in order. Steps S38, S39, and S40 are similar to steps S36, S23, and S24, respectively. The control unit 40 stops the operation of the inkjet recording apparatus 1 and ends the printing process.

[0092] As shown in FIG. 7, steps S16 to S24 correspond to the detection of each signal in all or selected drive ICs and the generation and acquisition of error information. Steps S31 to S40 correspond to additional detection, if necessary. As a result, if the detection result of each signal in the drive IC is not NG, the printing operation is executed in a loop of steps S15 to S18. If the detection result of each signal in the first-stage drive IC is NG, steps S21 and S22 prompt cable replacement. Note that if the detection result of each signal in the first-stage drive IC is also NG in the additional detection, step S34 prompts control board replacement. If the detection result of each signal in the first-stage drive IC is not NG and the detection result of each signal in the last-stage drive IC is NG, steps S23, S24, S38 to S40 prompt head 240 replacement.

[0093] As described above, according to this embodiment, the inkjet recording apparatus 1 includes driving ICs 251-253 and a control unit 40. Each driving IC 251-253 is connected to a predetermined group of piezoelectric elements in the head 240, which has nozzles that eject ink and piezoelectric elements 242, and drives the piezoelectric element group. The driving ICs 251-253 include input detection circuits 2514-2534. The input detection circuits 2514-2534 receive input signals, including data signals Sin representing ink ejection data and related to the driving of the corresponding piezoelectric element group, and detect whether the input signals are equal to or greater than a threshold value to generate a detection result. The input signals include a voltage VH, a signal PLSTM, a clock signal DCLK, and first and second output signals based on the data signal Sin. The driving ICs 251-253 are connected in series via the wiring for the data signal Sin. The control unit 40 selects one of the driving ICs 251-253 from which to read the detection result from the input detection circuit. The input detection circuits 2514 to 2534 are connected in parallel to the control unit 40.

[0094] Therefore, in a head 240 having driver ICs 251-253, parallel connection of input detection circuits prevents an increase in the number of signal lines, while selecting an appropriate driver IC and efficiently detecting input signals. For example, if one driver IC corresponds to 128 nozzles, 257 pieces of data are required for the driver ICs 251-253 for the data signal Sin to reach the final driver IC 253. Here, if only the first driver IC 251 is selected and the input signal is compared, only the data for one driver IC is required to be transferred, thereby saving time. This effect is particularly significant as the number of input signals, the number of driver ICs, and the number of nozzles corresponding to one driver IC increase.

[0095] The control unit 40 selects a drive IC from among the drive ICs 251 to 253 to read out the detection results in accordance with the detection time based on the printing conditions. This allows the input signal to be detected during detection time periods that correspond to the printing conditions and have a relatively large amount of time, such as at startup, between sheets, or during maintenance, thereby enabling more efficient detection of the input signal.

[0096] The control unit 40 selects the final-stage driving IC 253 from among the multiple driving ICs. Therefore, by detecting the input signal of the final-stage driving IC 253, it is possible to determine whether an error has occurred in the head 240 or the cable. Furthermore, by notifying (displaying) the error information, it is possible to prompt the user to replace the head 240 or the cable.

[0097] The control unit 40 selects the first-stage driving IC 251 from among the multiple driving ICs. The control unit 40 compares the input signal of the input source to the selected driving IC with the detection result read from the input detection circuit of that driving IC. If the detection result of the first-stage driving IC 251 differs from the input signal of the input source, the control unit 40 notifies (displays) error information indicating a problem with the cable between the control board including the control unit 40 and the head 240. Therefore, by detecting the input signal of the last-stage driving IC 251, it is possible to determine an error (cable break) in the stage before the first-stage driving IC 251. Furthermore, the notification of the error information can prompt the user to replace the cable.

[0098] The control unit 40 compares the input signal of the selected driving IC with the detection result read from the input detection circuit of that driving IC. If the detection result of the first-stage driving IC 251 matches the input signal of the input source and the detection result of a selected driving IC other than the first-stage driving IC differs from the input signal of the input source, the control unit 40 notifies error information indicating a malfunction of the head 240. Therefore, by detecting the input signals of the driving ICs 251 to 253, it is possible to more accurately determine an error due to a malfunction within the head 240. Furthermore, the notification of the error information can prompt the user to replace the head 240.

[0099] After notifying the error information, the control unit 40 selects the driving ICs 251-253 and reads out the additional detection results. The control unit 40 compares the input signal of the input source to the selected driving ICs 251-253 with the additional detection results read out from the input detection circuits 2514-2534. The control unit 40 clears the error information if the additional detection results match the input signal of the input source. Therefore, after the error information is generated, the error state can be released if the malfunction is resolved by the user repairing the component (cable or head 240) by replacing it.

[0100] If the additional detection result of the first-stage driving IC 251 differs from the input signal of the input source, the control unit 40 notifies error information indicating a malfunction of the control board. In this case, if the malfunction is not resolved by the user repairing the head unit 24 by replacing a component (cable or head 240), an error indicating a malfunction of the control board can be determined. Furthermore, the notification of the error information can prompt the user to replace the control board.

[0101] The input detection circuits 2514 to 2534 detect the logic (first and second output signals) of the first and last stages of the shift registers 2511 to 2531 that store the data signal Sin of the ejection data as input signals. This reduces the number of input signals to be detected and compared, reduces the processing load on the input detection circuits 2514 to 2534, and prevents the size of the input detection circuits 2514 to 2534 from increasing.

[0102] (Variation) A modification of the above embodiment will be described with reference to Fig. 8. Fig. 8 is a diagram showing a wiring board 250 of this modification.

[0103] In the above embodiment, the data signal Sin is connected in series among the drive ICs 251, 252, and 253 of the head 240, and other signals are input separately to each drive IC. This modified example is based on a concept similar to connecting the data signal Sin in series. In this modified example, the data signal Sin is connected in series among the multiple drive ICs of the head, and other signals are wired in a single stroke (daisy chain wiring).

[0104] The inkjet recording apparatus 1 used in this modified example is similar to the above embodiment, except that the head 240 of the image forming unit 20 is replaced with a head having a wiring board 250 shown in Fig. 8. The configuration of the wiring board 250 will now be described with reference to Fig. 8.

[0105] The head of this modified example has a piezoelectric element 242 (not shown in FIG. 8) and a wiring board 250. Similar to head 240, wiring board 250 has driving ICs 251, 252, and 253. Note that address setting units 2515, 2525, and 2535 are not shown in driving ICs 251, 252, and 253 of wiring board 250. The rectangles in FIG. 8 with the symbols of each signal drawn on them indicate pads to which the respective signals are input or output.

[0106] The circuit elements of the driving ICs 251 to 253 are connected by unicursal wiring that carries the clock signal DCLK, the latch signal LAT, the signal PLSTM, and the voltage VH. For example, for the clock signal DCLK, a wiring is connected from the control board to the pad of the shift register 2511. A wiring is also short-circuited between the pad of the shift register 2511 and the pad of the shift register 2521. A wiring is also short-circuited between the pad of the shift register 2521 and the pad of the shift register 2531. The clock signal DCLK flows through these wirings in the order of the control board → shift register 2511 → shift register 2521 → shift register 2531.

[0107] The wiring for the latch signal LAT, the signal PLSTM, and the voltage VH, like the wiring for the clock signal DCLK, is a single-stroke wiring for each circuit element of the driving ICs 251 to 253. In each circuit element of the driving ICs 251 to 253, the output signals for each of the above signals are not signals that have passed through the inside of each circuit element of the driving ICs 251 to 253. Therefore, by detecting each of the above signals, it is possible to determine only the break in the wiring between the driving ICs.

[0108] On the other hand, the wiring for the data signal Sin is connected in series to the driving ICs 251 to 253, similar to the head 240. For example, the data signal Sin input from the control unit 40 is input to the shift register 2511 and output as the data signal Sout. The data signal Sout is input as the data signal Sin to the shift register 2521 and output as the data signal Sout. The data signal Sout is input as the data signal Sin to the shift register 2531.

[0109] The printing process executed by the control unit 40 is similar to the printing process (FIGS. 5 and 6) of the above embodiment.

[0110] As described above, according to this modification, the inkjet recording apparatus 1 includes driving ICs 251-253 and a control unit 40. Each driving IC 251-253 is connected to a predetermined group of piezoelectric elements in the head 240, which has nozzles that eject ink and piezoelectric elements 242, and drives the piezoelectric element group. The driving ICs 251-253 include input detection circuits 2514-2534. The input detection circuits 2514-2534 receive input signals, including data signals Sin for ink ejection data, related to the driving of the corresponding piezoelectric element group, and detect whether the input signals are equal to or greater than a threshold value to generate a detection result. The input signals are a voltage VH, a signal PLSTM, and a clock signal DCLK. The driving ICs 251-253 are connected by a unicursal wiring that is the wiring for the input signals. The control unit 40 selects one of the driving ICs 251-253 from which to read the detection result from the input detection circuit.

[0111] Therefore, in the head 240 having the drive ICs 251 to 253, an appropriate drive IC can be selected and input signals can be detected efficiently. In particular, the greater the number of input signals, the number of drive ICs, and the number of nozzles corresponding to one drive IC, the greater the effect.

[0112] In the above description, an example has been disclosed in which a ROM is used as a computer-readable medium for the program according to the present invention, but this is not limiting. Other computer-readable media include non-volatile memory such as flash memory and portable recording media such as CD-ROM. Furthermore, a carrier wave is also applicable to the present invention as a medium for providing data for the program according to the present invention via a communication line.

[0113] The above-described embodiments and modifications are merely examples of the liquid ejection device, signal detection method, and program according to the present invention, and are not intended to limit the scope of the present invention. For example, the above-described embodiments and modifications may be combined as appropriate.

[0114] Furthermore, the inkjet recording device 1 uses a one-pass image formation method, but this is not limited to this. For example, the image formation method may be a scan method in which the recording medium is transported in the transport direction and the head unit is moved in the width direction to form an image. In a scan-type inkjet recording device, the signal detection time also takes into account the time it takes for the head unit to move.

[0115] While embodiments and variations of the present invention have been described and illustrated in detail, the disclosed embodiments and variations have been made for purposes of illustration and example only, and are not intended to be limiting. The scope of the present invention should be interpreted by the terms of the appended claims. [Explanation of symbols]

[0116] 1. Inkjet recording device 10 Paper feed section 11 Paper tray 12 Media supply section 20 Image forming unit 21 Conveyor 211 Transport drum 2111 Conveying surface 22 Delivery Unit 221 Swing arm section 222 Delivery drum 23 Paper heating section 24, 24Y, 24M, 24C, 24K head unit 240 head 241 nozzle 2411 Nozzle opening 2412 Nozzle surface 242 Piezoelectric element 243 Carriage 25 Head drive unit 250 wiring board 251, 252, 253 driver IC 2511,2521,2531 shift registers 2512, 2522, 2532 latch circuit 2513, 2523, 2533 output circuit 2514, 2524, 2534 input detection circuit 2515, 2525, 2535 Address setting section 26 Fixing section 27 Delivery Department 271 Delivery Drum 272 Belt loop 30 Paper output section 31 Paper output tray 40 Control Unit 50 Storage section 61 Conveyor drive unit 62 Head unit moving part 63 Cleaning Department 70 Operation display section 80 Communications Department 2. Recording media 3 PC

Claims

1. a plurality of integrated circuits connected to predetermined groups of piezoelectric elements of a head having a plurality of nozzles and piezoelectric elements for ejecting ink, and for driving the groups of piezoelectric elements; each of the integrated circuits includes an input signal of ink ejection data, and has a detection section that receives an input signal related to driving a corresponding piezoelectric element group, detects whether the input signal is equal to or greater than a threshold value, and generates a detection result; the plurality of integrated circuits are connected in series via wiring for signals of the ejection data; a control unit for selecting an integrated circuit from among the plurality of integrated circuits, the integrated circuit from which the detection result is read out from the detection unit; The liquid ejection device, wherein the plurality of detection units are connected in parallel to the control unit.

2. The liquid ejection device according to claim 1 , wherein the control unit selects an integrated circuit from which to read the detection result in accordance with a detection possible time based on printing conditions.

3. The liquid ejection device according to claim 1 , wherein the control unit selects a final stage integrated circuit from among the plurality of integrated circuits.

4. The liquid ejection device according to claim 1 , wherein the control unit selects a first-stage integrated circuit from among the plurality of integrated circuits.

5. The liquid ejection device described in claim 4, wherein the control unit compares the input signal of the input source to the selected integrated circuit with the detection result read from the integrated circuit, and if the detection result of the first stage integrated circuit differs from the input signal of the input source, notifies error information indicating a malfunction of the cable between the control board including the control unit and the head.

6. The control unit compares the input signal of the input source to the selected integrated circuit with the detection result read from the integrated circuit, and if the detection result of the first stage integrated circuit matches the input signal of the input source and the detection result of the selected integrated circuit other than the first stage differs from the input signal of the input source, notifies error information indicating a malfunction of the head.

7. A liquid ejection device as described in claim 5 or 6, wherein the control unit, after notifying the error information, selects the multiple integrated circuits, reads out the additional detection results, compares the input signal of the input source to the selected integrated circuit with the additional detection results read out from the integrated circuit, and clears the error information if the additional detection results match the input signal of the input source.

8. The liquid ejection device according to claim 7 , wherein the control unit notifies error information indicating a malfunction of a control board including the control unit when the additional detection result of the integrated circuit at the first stage differs from the input signal of the input source.

9. The liquid ejection device according to claim 1 , wherein the detection unit detects logic of the first and last stages of a shift register that stores the ejection data signal.

10. a plurality of integrated circuits connected to predetermined groups of piezoelectric elements of a head having a plurality of nozzles and piezoelectric elements for ejecting ink, and for driving the groups of piezoelectric elements; Each of the integrated circuits has a detection unit that receives an input signal related to driving a corresponding piezoelectric element group, detects whether the input signal is equal to or greater than a threshold value, and generates a detection result; the plurality of integrated circuits are connected by unicursal wiring of the input signals, A liquid ejection device including a control unit that selects, from the plurality of integrated circuits, an integrated circuit that reads out a detection result from the detection unit.

11. The liquid ejection device according to claim 10 , wherein the control unit selects an integrated circuit from which to read the detection result in accordance with a detection possible time based on printing conditions.

12. The liquid ejection device according to claim 10 , wherein the control unit selects a final stage integrated circuit from among the plurality of integrated circuits.

13. The liquid ejection device according to claim 10 , wherein the control unit selects a first-stage integrated circuit from among the plurality of integrated circuits.

14. a plurality of integrated circuits connected to predetermined groups of piezoelectric elements of a head having a plurality of nozzles and piezoelectric elements for ejecting ink, and for driving the groups of piezoelectric elements; each of the integrated circuits includes an input signal of ink ejection data, and has a detection section that receives an input signal related to driving a corresponding piezoelectric element group, detects whether the input signal is equal to or greater than a threshold value, and generates a detection result; a signal detection method for a liquid ejection device in which the plurality of integrated circuits are connected in series via wiring for input signals of the ejection data, a control step of selecting an integrated circuit from the plurality of integrated circuits by a control unit, the integrated circuit being used to read out a detection result from the detection unit; The signal detection method, wherein the plurality of detection units are connected in parallel to the control unit.

15. a plurality of integrated circuits connected to predetermined groups of piezoelectric elements of a head having a plurality of nozzles and piezoelectric elements for ejecting ink, and for driving the groups of piezoelectric elements; Each of the integrated circuits has a detection unit that receives an input signal related to driving a corresponding piezoelectric element group, detects whether the input signal is equal to or greater than a threshold value, and generates a detection result; a signal detection method for a liquid ejection device, wherein the plurality of integrated circuits are connected by unicursal wiring of the input signal, A signal detection method including a control step in which a control unit selects an integrated circuit from the plurality of integrated circuits from which a detection result is read out from the detection unit.

16. a plurality of integrated circuits connected to predetermined groups of piezoelectric elements of a head having a plurality of nozzles and piezoelectric elements for ejecting ink, and for driving the groups of piezoelectric elements; each of the integrated circuits includes an input signal of ink ejection data, and has a detection section that receives an input signal related to driving a corresponding piezoelectric element group, detects whether the input signal is equal to or greater than a threshold value, and generates a detection result; The plurality of integrated circuits are connected in series via wiring for input signals of the ejection data to a computer of the liquid ejection device, a control unit that selects an integrated circuit from the plurality of integrated circuits to read out a detection result from the detection unit; It functions as The plurality of detection units are connected in parallel to the control unit.

17. a plurality of integrated circuits connected to predetermined groups of piezoelectric elements of a head having a plurality of nozzles and piezoelectric elements for ejecting ink, and for driving the groups of piezoelectric elements; Each of the integrated circuits has a detection unit that receives an input signal related to driving a corresponding piezoelectric element group, detects whether the input signal is equal to or greater than a threshold value, and generates a detection result; The plurality of integrated circuits are connected to a computer of the liquid ejection device by a single-stroke wiring of the wiring of the input signal, a control unit that selects an integrated circuit from the plurality of integrated circuits to read out a detection result from the detection unit; A program to function as a

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