Inkjet head control device

Abstract

To provide an inkjet head control device that can reduce CPU load, shorten communication time, and improve the control efficiency of the driver IC. [Solution] To achieve the above objective, an inkjet head control device according to one embodiment of the present invention comprises a control master unit. The control master unit transmits control commands from an external source to a plurality of driver ICs (Integrated Circuits) that control the inkjet head, and outputs the responses from the plurality of driver ICs to the outside. This makes it possible to reduce the load on the CPU and shorten the communication time, thereby improving the control efficiency of the driver ICs.

Description

Technical Field

[0005] , ,

[0001] The present invention relates to an inkjet head control device applicable to an inkjet printer or the like.

Background Art

[0002] Conventionally, an inkjet printer that prints a pattern according to image data includes an actuator for ejecting ink and a driver IC that drives the actuator by a control signal from an inkjet head control circuit that controls the inkjet head.

[0003] For example, in Patent Document 1, there is disclosed an inkjet printer including an actuator, a driver IC that is connected to a plurality of signal lines to which control signals from an inkjet head control circuit are input and drives the actuator by a drive waveform generated according to the control signal, and a non-volatile memory that is connected to one of the plurality of signal lines and stores unique information of the inkjet head. Further, in Patent Document 2, there is disclosed a droplet ejection device including a diaphragm, an actuator, a cavity in which the internal pressure filled with a liquid is increased or decreased by the displacement of the diaphragm, and a nozzle, a drive circuit that drives the actuator, and residual vibration detection means that detects residual vibration of the diaphragm displaced by the actuator, and head abnormality detection means that detects a head abnormality of the droplet ejection head from the vibration pattern of the residual vibration.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, while Patent Document 1 describes register settings for multiple driver ICs, it does not mention how to improve the efficiency of register settings between the CPU and each driver IC. Furthermore, Patent Document 2 states that detecting residual vibration for all nozzles of a line-type head requires switching the detection circuit for each nozzle, resulting in a heavy control load.

[0006] In view of the above circumstances, the object of the present invention is to provide an inkjet head control device that can reduce the load on the CPU, shorten communication time, and improve the control efficiency of the driver IC. [Means for solving the problem]

[0007] To achieve the above objective, an inkjet head control device according to one embodiment of the present invention comprises a control master unit. The control master unit transmits control commands from an external source to a plurality of driver ICs (Integrated Circuits) that control the inkjet head, and outputs the responses from the plurality of driver ICs to the outside. [Effects of the Invention]

[0008] According to the present invention, it is possible to reduce the CPU load and shorten the communication time, thereby improving the control efficiency of the driver IC.

[0009] Furthermore, the effects described herein are not necessarily limited to those described herein, and may include any of the effects described herein. [Brief explanation of the drawing]

[0010] [Figure 1] This diagram shows an example of an inkjet printer configuration. [Figure 2] This is a block diagram showing an example configuration of an inkjet head control device. [Figure 3] This flowchart shows the control system for inspecting nozzle abnormalities. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0012] Figure 1 shows an example configuration of an inkjet printer 10.

[0013] As shown in Figure 1, the inkjet printer 10 includes a control unit 20, a communication interface 11, a display unit 12, an operation unit 13, a transport unit 14, an ejection unit 15, an inkjet head 30, and a power supply circuit 16. In this embodiment, the inkjet printer 10 is a line-head type inkjet printer.

[0014] The control unit 20 performs various operations of the inkjet printer 10, such as printing and detecting ejection abnormalities of the inkjet head 30, which will be described later. For example, the control unit 20 may use a CPU (Central Processing Unit) 21, ROM (Read Only Memory) 22, RAM (Random Access Memory) 23, etc.

[0015] For example, the CPU 21 performs various processes based on the program stored in the ROM 22. The CPU 21 also outputs print data for forming an image on the recording paper to the inkjet head control device 40, which will be described later. For example, the CPU 21 also outputs control signals that instruct the transport unit 14 to transport the recording paper.

[0016] ROM22 is a read-only non-volatile memory that stores programs and data used by those programs.

[0017] RAM23 is a volatile memory that functions as working memory, temporarily storing data being processed by CPU21 and programs being executed by CPU21.

[0018] Note that the configuration of the control unit 20 is not limited. For example, an EEPROM (Electrically Erasable Programmable Read-Only Memory), which is a type of non-volatile memory, or the like may be provided.

[0019] The communication I / F 11 is an interface for communicating with other devices. For example, the communication I / F 11 may be used to transmit print data to the inkjet printer 10. Note that the communication I / F 11 may perform wireless communication with other devices according to a standard such as Bluetooth (registered trademark) or Wi-fi (registered trademark).

[0020] The display unit 12 displays a screen for notifying an abnormality of the inkjet head 30, a GUI (Graphical User Interface) for setting the inkjet printer 10 and instructing operations, and the like. For example, the display unit 12 may use a liquid crystal display, an organic EL display, or the like. In addition to this, the display unit 12 may include a speaker or the like that can output a sound for notifying an abnormality of the inkjet head.

[0021] The operation unit 13 can command various operations of the inkjet printer 10 by a user performing a predetermined operation. For example, the operation unit 13 may use buttons, a touch panel, or the like. Also, the display unit 12 and the operation unit 13 may be integrally configured with a display having a built-in touch sensor.

[0022] The conveyance unit 14 includes a conveyance path for conveying the recording paper by rotating a belt, a roller, or the like, a motor for driving the conveyance path, and a drive circuit for driving the motor. For example, the conveyance unit 14 causes the recording paper accommodated in the paper feed cassette to pass through the inkjet head 30 and conveys the recording paper on which an image is formed to a paper discharge tray for accommodating it.

[0023] The inkjet head 30 forms an image on the recording paper by ejecting ink onto the recording paper held by the rollers. For example, the inkjet head 30 includes nozzles for ejecting ink, multiple head units corresponding to each color such as cyan, magenta, yellow, and black, multiple ink cartridges that supply ink to each head unit, and actuators that deform in response to the applied voltage.

[0024] In this embodiment, the inkjet head 30 is equipped with an inkjet head control device 40 that controls the driving of the inkjet head 30. In this embodiment, the inkjet head control device 40 performs an abnormality check on the nozzles of the inkjet head 30 based on the register settings input from the control unit 20 (CPU 21). A specific example is explained in Figure 3.

[0025] In this embodiment, the inkjet head control device 40 drives the inkjet head 30 according to the print data input from the control unit 20 (CPU 21) to form an image on the recording paper based on the print data. For example, the inkjet head control device 40 is composed of a control circuit that controls the ink ejection timing by driving an actuator corresponding to the head unit.

[0026] The power supply circuit 16 converts AC power supplied from a commercial power source (not shown) into DC power and supplies it to each component within the inkjet printer 10.

[0027] The configuration of the inkjet printer 10 is not limited to the above, and various configurations may be included depending on the application and function. For example, sensors for detecting the ink level of the ink cartridge and the ambient temperature may be included.

[0028] Figure 2 is a block diagram showing an example configuration of the inkjet head control device 40. In addition to the inkjet head control device 40, the control unit 20 is also partially shown in Figure 2.

[0029] As shown in Figure 2, the inkjet head 30 has a plurality of driver ICs 31 (eight in Figure 2) that drive actuators (not shown) of the inkjet head 30.

[0030] The driver IC 31 includes a register for temporarily storing image data input from the inkjet head control device 40. The driver IC 31 also sets driving conditions such as the period and shape of the drive waveform for driving the actuator based on the register settings input from the inkjet head control device 40. The driver IC 31 also drives the actuator by applying a potential to the actuator's electrodes based on the image data transmitted from the inkjet head control device 40.

[0031] The inkjet head control device 40 controls the inkjet heads 30 for each color, and four of them are shown in the diagram, corresponding to the four colors: cyan, magenta, yellow, and black.

[0032] The inkjet head control device 40 includes a driver IC control master 41, a detection unit 42, a driver register IF 43, an image processing unit 44, an image rearrangement unit 45, and a driver control unit 46.

[0033] The driver IC control master 41 controls multiple driver ICs 31 simultaneously. In this embodiment, the driver IC control master 41 transmits control commands from the control unit 20 (CPU 21) to all driver ICs 31 and outputs responses from all driver ICs 31 to the control unit 20. For example, the driver IC control master 41 sets register settings (such as setting driving conditions) for all driver ICs 31. The driver IC control master 41 also performs waveform checks on residual waveforms acquired by the detection unit 42.

[0034] In this embodiment, the control unit 20 (CPU 21) corresponds to an example of an external device that outputs control commands. External devices also include those outside the inkjet printer 10, such as a computer that operates the inkjet printer 10.

[0035] The control command also includes a command to set registers for driving the inkjet head 30. The register settings also include driving conditions for the inkjet head 30 for checking for abnormalities in the nozzles of the inkjet head 30. The control command is not limited, and control commands including various external instructions may be managed by the driver IC control master 41.

[0036] Here, the residual waveform refers to the waveform of the damped vibration (residual vibration) of the bottom plate (diaphragm) of the pressure chamber (cavity) mounted on the inkjet head 30, from the operation of ejecting ink in response to the drive signal from the driver IC 31 until the next drive signal is input and ink droplets are ejected again.

[0037] The detection unit 42 detects abnormalities in the nozzles of the inkjet head 30. For example, the detection unit 42 acquires residual waveforms to detect abnormal situations such as whether the nozzles are properly filled with ink or whether nozzle clogging (failure to eject) has occurred. In this embodiment, the detection unit 42 acquires residual waveforms by vibrating the nozzles of the inkjet head 30 with the driver IC 31 and outputs the residual waveforms to the driver IC control master 41.

[0038] The driver register IF43 controls the driver IC 31. In this embodiment, the driver register IF43 sets the register of the driver IC 31 based on control instructions from the driver IC control master 41.

[0039] The image processing unit 44 performs correction processing on the image data. For example, the image processing unit 44 may perform various corrections on the image data supplied from the control unit, such as noise reduction, brightness correction, monochrome image conversion, edge enhancement, and scaling. The type and method of correction processing are not limited, and color correction or contrast correction may be performed, or histogram conversion may be used.

[0040] The image rearrangement unit 45 rearranges the pixels of the raster image input from the image processing unit 44 to match the two-dimensional arrangement of the nozzles of the inkjet head 30.

[0041] The driver control unit 46 controls the driver IC corresponding to each nozzle based on the image data supplied from the control unit 20.

[0042] Figure 3 is a flowchart showing the control system for inspecting nozzle abnormalities.

[0043] As shown in Figure 3, the control unit 20 starts an inspection to check for any abnormalities in the nozzles of the inkjet head 30, performs a focused nozzle check and a non-ejection check, sets the registers in the driver IC control master 41, and starts the driver IC control master 41 (steps 101 and 102).

[0044] The driver IC control master 41 performs register settings on all eight driver ICs 31 via the driver register IF43 (steps 103 and 104). For example, the register settings include settings necessary to inspect nozzle abnormalities, such as nozzle selection, waveform, and detection period.

[0045] Furthermore, the driver IC control master 41 activates the detection unit 42, which detects the residual waveform of each nozzle (step 105). The detection unit 42 acquires the residual waveform by obtaining the detection trigger output from the driver IC control master 41 (steps 106, 107).

[0046] The driver IC control master 41 performs a waveform check on the residual waveform acquired from the detection unit 42 (step 108). For example, the driver IC control master 41 checks the residual waveform to see if the number of pulses or the width meets a threshold.

[0047] The driver IC control master 41 determines from the waveform check results whether or not there is a problem with any of the nozzles (step 109). If there is a problem with a nozzle (YES in step 109), the location of the problematic nozzle is recorded (step 110).

[0048] The driver IC control master 41 determines whether the waveform check has been completed for all nozzles (step 111). If there are any nozzles whose waveforms have not been checked (NO in step 111), those nozzles are selected (step 112), and the process returns to step 104 to detect residual waveforms.

[0049] The residual waveform is checked repeatedly, and once the waveform check for all nozzles is complete (YES in step 111), the driver IC control master 41 notifies the control unit 20 of the detection result (step 113). The detection result includes information on the coordinates of the nozzle where the abnormality occurred.

[0050] The control unit 20 determines whether there is an abnormality in the nozzle based on the detection result from the driver IC control master 41 (step 114), and if there is an abnormality (YES in step 114), it checks the coordinates of the nozzle (step 115).

[0051] When starting the driver IC control master 41, the driver register IF43 and the detection unit 42 may be directly connected to the driver IC control master 41 from the register setting bus 50 shown in Figure 2 (see dashed line 51 in Figure 2) to reduce bus congestion. For example, when the register is set by the driver IC control master 41, the CPU 21 switches from the shared path (register setting bus 50, corresponding to the first communication path) to a dedicated path (see dashed line 51 in Figure 2, corresponding to the second communication path), and switches from the dedicated path to the shared path when a detection result is notified. In other words, in the case of a dedicated path, the driver register IF43 and residual waveform detection (detection unit 42) cannot be accessed from other masters such as the CPU 21. Also, checking the driver IC 31 in detail with hardware may make the circuit complex and reduce flexibility, so the driver IC control master 41 may check and filter all nozzles, and the CPU 21 may check a few problematic nozzles in detail.

[0052] Furthermore, in order to debug or check the details of a malfunctioning nozzle, the driver register IF43 may be directly controlled by the control unit 20 without going through the driver IC control master 41. Specifically, the control unit 20 may set the registers for each driver IC 31 in the driver register IF43, and the response from the detection unit 42 may be output to the control unit 20 via the driver register IF43.

[0053] Furthermore, in addition to the two categories of abnormal or normal, the nozzle detection result based on the check of residual waveforms from the driver IC control master 41 and the detection unit 42 may also be classified into moderate and high degrees by setting a threshold level for the waveform check, and this classification may be notified to the control unit 20.

[0054] Furthermore, if the driver IC control master 41 has already identified a nozzle with an abnormality, it may skip inspecting that nozzle, or it may only notify the control unit 20 if the status of an abnormal or normal nozzle changes.

[0055] Furthermore, nozzle clogging checks may be performed periodically, such as during printing, in addition to when the inkjet printer 10 is started. For example, while printing is in progress, the printer may detect negation of the VSYNC image ejection timing signal, check the number of nozzles that can be inspected during the inter-paper time, and repeat this operation to periodically inspect all nozzles during printing.

[0056] As described above, the inkjet head control device 40 according to this embodiment includes a driver IC control master 41 that transmits control commands from an external source to a plurality of driver ICs 31 that control the inkjet head 30, and outputs the responses from the plurality of driver ICs 31 to the outside. This makes it possible to reduce the load on the CPU.

[0057] Conventionally, when an inkjet printer is started up, a method is known to check whether the nozzles of the print head are properly filled with ink and whether there are any nozzle clogs (failure to eject ink). This is done by vibrating the nozzles of the print head with a driver IC and checking the residual vibration. However, checking all the nozzles of all colors by having the CPU directly control the driver IC is difficult because there are many nozzles (approximately 1024 x 8 x 4 colors), and the time required for register control is also high, resulting in a heavy CPU load.

[0058] In this technology, in a line-head type inkjet device having driver ICs that control multiple inkjet heads, a control master for the driver ICs is placed to assist the CPU in setting the registers of the driver ICs and detecting and controlling nozzle abnormalities. This reduces the CPU load and shortens communication time, thereby improving the control efficiency of the driver ICs. [Explanation of Symbols]

[0059] 10… Inkjet printers 20... Control Unit 21…CPU 30…Inkjet head 31…Driver IC 40…Inkjet head control device 41…Driver IC control master 42...Detection unit

Claims

1. A control master unit transmits external control commands to multiple driver ICs (Integrated Circuits) that control the inkjet head, and outputs the responses from the multiple driver ICs to the outside. An inkjet head control device equipped with the following.

2. An inkjet head control device according to claim 1, The control command includes a command to set registers for driving the inkjet head, The register settings include driving conditions for the inkjet head for checking for abnormalities in the nozzles of the inkjet head. Inkjet head control device.

3. An inkjet head control device according to claim 1 or 2, further, The system includes an inspection unit that checks for abnormalities in the nozzles of the inkjet head based on the response from the driver IC. The control master unit outputs the detection results of the inspection unit to the outside when all of the nozzles have been inspected by the inspection unit. Inkjet head control device.

4. An inkjet head control device according to claim 3, The inspection unit inspects the plurality of nozzles in predetermined numbers. Inkjet head control device.

5. An inkjet head control device according to claim 1 or 2, The control master unit switches from the first communication path to a second communication path different from the first communication path when it receives a control command from an external source, and switches from the second communication path to the first communication path when it receives a response. Inkjet head control device.

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