JP7809955B2 - liquid discharge device - Google Patents

Description

The present invention relates to a liquid ejection device that ejects liquid from a nozzle.

Patent Document 1 describes an image recording device that includes an inspection unit that periodically inspects the recording elements of a print head for abnormalities; a determination unit that determines whether the recording elements can be used based on the inspection results of the inspection unit; and a compensation unit that disables recording elements that are determined to be unusable by the determination unit and compensates for image defects caused by the disabled recording elements.

JP 2016-49631 A

Some liquid ejection devices, which eject liquid from multiple nozzles to form images on a receiving medium, automatically execute a recovery process to restore the ejection performance of abnormal nozzles by discharging liquid from the nozzles, depending on the number of nozzles determined to be abnormal in ejection performance through periodic nozzle ejection tests. Some liquid ejection devices also form a test pattern on the receiving medium when a user inputs an instruction into an input unit to form a test pattern on the receiving medium to check whether a nozzle is abnormal. The liquid ejection device then executes the recovery process when the user checks the test pattern formed on the receiving medium and inputs a recovery execution instruction from the user into the input unit.

In the above-mentioned liquid ejection device, if the user decides whether or not to perform recovery processing and then the recovery processing is automatically performed in response to a periodic ejection inspection, liquid will be consumed unnecessarily. In other words, if the user decides to perform recovery processing, the nozzles will be in a recovered state, and if the user decides not to perform recovery processing, the user will not need to recover the nozzles. Therefore, if automatic recovery processing is performed after the user decides whether or not to perform recovery processing, a recovery processing that the user does not want will be performed, and liquid will be consumed unnecessarily.

Therefore, an object of the present invention is to provide a liquid ejection device that can reduce unnecessary liquid consumption after a test pattern formation process has been performed.

In a first aspect, the liquid ejection device of the present invention comprises a liquid ejection head having a plurality of nozzles for ejecting liquid, a signal output unit that outputs a determination signal according to whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to check whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid, recovery means that performs recovery operation to discharge liquid from the nozzle, an input unit for a user to input predetermined instructions, and a control unit. When a user inputs a test pattern formation instruction into the input unit to form a test pattern on the ejection-receiving medium to confirm whether or not the nozzle is the abnormal nozzle, the control unit executes a test pattern formation process to form the test pattern on the ejection-receiving medium by ejecting liquid from the multiple nozzles, and when a user inputs a user judgment instruction into the input unit as to whether or not to perform the recovery operation corresponding to the test pattern formed on the ejection-receiving medium by the test pattern formation process, the control unit determines whether or not to cause the recovery means to perform the recovery operation based on the user judgment instruction, causes the test drive to be performed after a first condition is satisfied, and if it is determined that the number of abnormal nozzles is equal to or greater than a threshold based on the judgment signal output from the signal output unit during the test drive, causes the recovery means to execute an automatic recovery process to perform the recovery operation, and after the test pattern formation process has been performed, does not execute the automatic recovery process until at least a second condition different from the first condition is satisfied, regardless of whether or not the recovery operation based on the user judgment instruction has been performed.
In a second aspect, the liquid ejection device of the present invention comprises a liquid ejection head having a plurality of nozzles for ejecting liquid, a signal output unit that outputs a determination signal according to whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to check whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid, recovery means that performs recovery operation to discharge liquid from the nozzle, an input unit for a user to input predetermined instructions, and a control unit. When a user inputs a test pattern formation instruction into the input unit to form a test pattern on the ejection-receiving medium to confirm whether or not the nozzle is the abnormal nozzle, the control unit executes a test pattern formation process to form the test pattern on the ejection-receiving medium by ejecting liquid from the multiple nozzles, and when a user inputs a user judgment instruction into the input unit as to whether or not to perform the recovery operation corresponding to the test pattern formed on the ejection-receiving medium by the test pattern formation process, the control unit determines whether or not to cause the recovery means to perform the recovery operation based on the user judgment instruction, causes the test drive to be performed after a first condition is satisfied, and if it is determined that the number of abnormal nozzles is equal to or greater than a threshold based on the judgment signal output from the signal output unit during the test drive, causes the recovery means to execute an automatic recovery process to perform the recovery operation, and after the test pattern formation process has been performed, does not execute the automatic recovery process until at least a second condition different from the first condition is satisfied, regardless of whether or not the recovery operation based on the user judgment instruction has been performed. The device may further include a clock unit that outputs a time signal indicating a time, and the first condition is that the time signal indicating a predetermined time has been output from the clock unit.
In a third aspect, the liquid ejection device of the present invention comprises a liquid ejection head having a plurality of nozzles for ejecting liquid, a signal output unit that outputs a determination signal according to whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to check whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid, recovery means that performs recovery operation to discharge liquid from the nozzle, an input unit for a user to input predetermined instructions, and a control unit. When a user inputs a test pattern formation instruction into the input unit to form a test pattern on the ejection-receiving medium to confirm whether or not the nozzle is the abnormal nozzle, the control unit executes a test pattern formation process to form the test pattern on the ejection-receiving medium by ejecting liquid from the multiple nozzles, and when a user inputs a user judgment instruction into the input unit as to whether or not to perform the recovery operation corresponding to the test pattern formed on the ejection-receiving medium by the test pattern formation process, the control unit determines whether or not to cause the recovery means to perform the recovery operation based on the user judgment instruction, causes the test drive to be performed after a first condition is satisfied, and if it is determined that the number of abnormal nozzles is equal to or greater than a threshold based on the judgment signal output from the signal output unit during the test drive, causes the recovery means to execute an automatic recovery process to perform the recovery operation, and after the test pattern formation process has been performed, does not execute the automatic recovery process until at least a second condition different from the first condition is satisfied, regardless of whether or not the recovery operation based on the user judgment instruction has been performed. The apparatus further includes a memory unit, and the control unit stores in the memory unit the cumulative number of sheets of ejection medium on which an image is formed by an ejection operation that causes the liquid ejection head to eject liquid from the multiple nozzles toward the ejection medium, and the first condition is that the cumulative number of sheets stored in the memory unit reaches a predetermined number.
In a fourth aspect, the liquid ejection device of the present invention comprises a liquid ejection head having a plurality of nozzles for ejecting liquid, a signal output unit that outputs a determination signal according to whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to check whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid, recovery means that performs recovery operation to discharge liquid from the nozzle, an input unit for a user to input predetermined instructions, and a control unit. and a control unit configured to, when a user inputs to the input unit a test pattern formation instruction for forming a test pattern on a discharge-receiving medium to confirm whether the nozzle is the abnormal nozzle, execute a test pattern formation process for forming the test pattern on the discharge-receiving medium by ejecting liquid from the plurality of nozzles, and when the user inputs to the input unit a user determination instruction as to whether to execute the recovery operation corresponding to the test pattern formed on the discharge-receiving medium by the test pattern formation process, determine whether to cause the recovery unit to execute the recovery operation based on the user determination instruction, cause the control unit to perform the test drive after a first condition is satisfied, and, when it is determined that the number of abnormal nozzles is equal to or greater than a threshold based on the determination signal output from the signal output unit during the test drive, cause the recovery unit to execute an automatic recovery process for performing the recovery operation, and not execute the automatic recovery process until at least a second condition is satisfied after the test pattern formation process has been performed. The liquid ejection device further includes an apparatus abnormality output unit that outputs an apparatus abnormality signal when an apparatus abnormality other than the abnormal nozzle occurs in the liquid ejection device, and the first condition is that the apparatus abnormality signal has been output from the apparatus abnormality output unit.
In a fifth aspect, the liquid ejection device of the present invention comprises a liquid ejection head having a plurality of nozzles for ejecting liquid, a signal output unit that outputs a determination signal according to whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to check whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid, recovery means that performs recovery operation to discharge liquid from the nozzle, an input unit for a user to input predetermined instructions, and a control unit. When a user inputs a test pattern formation instruction into the input unit to form a test pattern on the ejection-receiving medium to confirm whether the nozzle is the abnormal nozzle, the control unit executes a test pattern formation process to form the test pattern on the ejection-receiving medium by ejecting liquid from the multiple nozzles, and when a user inputs a user judgment instruction into the input unit as to whether or not to perform the recovery operation corresponding to the test pattern formed on the ejection-receiving medium by the test pattern formation process, the control unit determines whether or not to cause the recovery means to perform the recovery operation based on the user judgment instruction, causes the test drive to be performed after a first condition is satisfied, and if it is determined that the number of abnormal nozzles is equal to or greater than a threshold value based on the judgment signal output from the signal output unit during the test drive, causes the recovery means to execute an automatic recovery process to perform the recovery operation, and does not execute the automatic recovery process after the test pattern formation process has been performed until at least a second condition is satisfied. Furthermore, when the control unit performs an ejection operation in which the liquid ejection head ejects liquid from the multiple nozzles toward the ejection medium, if the number of abnormal nozzles based on the judgment signal output from the signal output unit during the inspection drive performed after the first condition is satisfied is equal to or greater than a threshold value, the control unit executes the automatic recovery process prior to the ejection operation.
In a sixth aspect, the liquid ejection device of the present invention comprises a liquid ejection head having a plurality of nozzles for ejecting liquid, a signal output unit that outputs a determination signal according to whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to check whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid, recovery means that performs recovery operation to discharge liquid from the nozzle, an input unit for a user to input predetermined instructions, and a control unit. The control unit, when a user inputs a test pattern formation instruction to the input unit to form a test pattern on the ejection receiving medium to confirm whether the nozzle is the abnormal nozzle, executes a test pattern formation process to form the test pattern on the ejection receiving medium by ejecting liquid from the plurality of nozzles, and when a user inputs a user determination instruction to the input unit to determine whether to perform the recovery operation corresponding to the test pattern formed on the ejection receiving medium by the test pattern formation process, determines whether to cause the recovery unit to perform the recovery operation based on the user determination instruction, causes the test drive to be performed after a first condition is satisfied, and if it is determined that the number of abnormal nozzles is equal to or greater than a threshold based on the determination signal output from the signal output unit during the test drive, causes the recovery unit to perform an automatic recovery process to perform the recovery operation, and does not execute the automatic recovery process after the test pattern formation process has been performed until at least a second condition is satisfied. Furthermore, the control unit, when the test pattern formation process has been performed, does not execute the test drive after the first condition is satisfied until at least the second condition is satisfied.
In a seventh aspect, the liquid ejection device of the present invention comprises a liquid ejection head having a plurality of nozzles for ejecting liquid, a signal output unit that outputs a determination signal according to whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to check whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid, recovery means that performs recovery operation to discharge liquid from the nozzle, an input unit for a user to input predetermined instructions, and a control unit. The control unit, when a user inputs a test pattern formation instruction to the input unit to form a test pattern on the ejection receiving medium to check whether the nozzle is the abnormal nozzle, executes a test pattern formation process to form the test pattern on the ejection receiving medium by ejecting liquid from the plurality of nozzles, and when the user inputs a user determination instruction to the input unit as to whether to perform the recovery operation corresponding to the test pattern formed on the ejection receiving medium by the test pattern formation process, determines whether to cause the recovery unit to perform the recovery operation based on the user determination instruction, causes the control unit to perform the test drive after a first condition is satisfied, and if it is determined that the number of abnormal nozzles is equal to or greater than a threshold based on the determination signal output from the signal output unit during the test drive, causes the control unit to perform an automatic recovery process to cause the recovery unit to perform the recovery operation, and does not execute the automatic recovery process after the test pattern formation process has been performed until a second condition is satisfied, wherein the second condition is that the automatic recovery process is not executed a predetermined number of times after the test pattern formation process has been performed.
In an eighth aspect, the liquid ejection device of the present invention comprises a liquid ejection head having a plurality of nozzles for ejecting liquid, a signal output unit that outputs a determination signal according to whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to check whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid, recovery means that performs recovery operation to discharge liquid from the nozzle, an input unit for a user to input predetermined instructions, and a control unit. The control unit, when a user inputs a test pattern formation instruction to the input unit to form a test pattern on the ejection receiving medium to confirm whether the nozzle is the abnormal nozzle, executes a test pattern formation process to form the test pattern on the ejection receiving medium by ejecting liquid from the plurality of nozzles, and when the user inputs a user determination instruction to the input unit as to whether to perform the recovery operation corresponding to the test pattern formed on the ejection receiving medium by the test pattern formation process, determines whether to cause the recovery unit to perform the recovery operation based on the user determination instruction, causes the test drive to be performed after a first condition is satisfied, and if it is determined that the number of abnormal nozzles is equal to or greater than a threshold based on the determination signal output from the signal output unit during the test drive, causes the recovery unit to execute an automatic recovery process to perform the recovery operation, and does not execute the automatic recovery process after the test pattern formation process has been performed until at least a second condition is satisfied, which is that a predetermined period of time has elapsed since the test pattern formation process was performed.
In a ninth aspect, the liquid ejection device of the present invention comprises a liquid ejection head having a plurality of nozzles for ejecting liquid, a signal output unit that outputs a determination signal according to whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to check whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid, recovery means that performs recovery operation to discharge liquid from the nozzle, an input unit for a user to input predetermined instructions, and a control unit. When a user inputs a test pattern formation instruction into the input unit to form a test pattern on the ejection-receiving medium to confirm whether the nozzle is the abnormal nozzle, the control unit executes a test pattern formation process to form the test pattern on the ejection-receiving medium by ejecting liquid from the multiple nozzles, and when a user inputs a user judgment instruction into the input unit as to whether or not to perform the recovery operation corresponding to the test pattern formed on the ejection-receiving medium by the test pattern formation process, the control unit determines whether or not to cause the recovery means to perform the recovery operation based on the user judgment instruction, causes the test drive to be performed after a first condition is satisfied, and if it is determined that the number of abnormal nozzles is equal to or greater than a threshold value based on the judgment signal output from the signal output unit during the test drive, causes the recovery means to execute an automatic recovery process to perform the recovery operation, and does not execute the automatic recovery process after the test pattern formation process has been performed until at least a second condition is satisfied. The control unit further includes a memory unit, and when the user inputs the test pattern formation instruction to the input unit, the control unit performs the inspection drive before executing the test pattern formation process or after executing the test pattern formation process, and stores the abnormal nozzles based on the judgment signal output from the signal output unit during the inspection drive in the memory unit as abnormal nozzles for the test pattern, and the second condition is that the number of abnormal nozzles based on the judgment signal output from the signal output unit during the inspection drive performed after the first condition is satisfied is greater than the number of abnormal nozzles for the test pattern when the recovery means is not caused to perform the recovery operation based on the user judgment instruction.

With the liquid ejection device of the present invention, regardless of whether or not recovery operation is performed based on the user's decision in response to the results of the test pattern formed on the ejection receiving medium by the test pattern formation process, after the test pattern formation process has been performed, the automatic recovery process is not executed until the second condition is met. This makes it possible to reduce unnecessary liquid consumption.

1 is a schematic configuration diagram of a printer according to a first embodiment of the present invention; 10A and 10B are diagrams for explaining detection electrodes arranged in a cap, and the connection relationship between the detection electrodes and a high-voltage power supply circuit and a signal processing circuit. FIG. 10A is a diagram showing the change in voltage value of the detection electrode when ink is ejected from the nozzle, and FIG. 10B is a diagram showing the change in voltage value of the detection electrode when ink is not ejected from the nozzle. FIG. 2 is a block diagram showing the electrical configuration of the printer. 10 is a flowchart showing an operation when an abnormality in the printer is detected. 10 is a flowchart showing the operation of the printer when it is on standby. 10 is a flowchart showing the operation of the printer when printing a test pattern. 10 is a flowchart showing the operation of the printer during normal printing. 10 is a flowchart showing an operation when the inhibition of the recovery process of the printer is lifted. 10 is a flowchart showing a standby operation of a printer according to a second embodiment of the present invention. 10 is a flowchart showing an operation performed when the inhibition of recovery processing of a printer according to a second embodiment of the present invention is lifted. 10 is a flowchart showing an operation performed when the inhibition of recovery processing of a printer according to a third embodiment of the present invention is lifted. 10 is a flowchart showing a standby operation of a printer according to a fourth embodiment of the present invention. 10 is a flowchart showing an operation of a printer according to a fourth embodiment of the present invention during normal printing. 10 is a flowchart showing an operation when the inhibition of the recovery process of the printer according to the fourth embodiment of the present invention is lifted. 13 is a flowchart showing an operation of a printer according to a fifth embodiment of the present invention when printing a test pattern. 13 is a flowchart showing an operation when the inhibition of the recovery process of the printer according to the fifth embodiment of the present invention is lifted.

The following describes a preferred embodiment of the present invention.

<Overall printer configuration>
As shown in FIG. 1, the printer 1 (the "liquid ejection device" of the present invention) according to the first embodiment includes a carriage 2, a subtank 3, an inkjet head 4 (the "liquid ejection head" of the present invention), a platen 5, transport rollers 6 and 7, a maintenance unit 8, etc.

The carriage 2 is supported by two guide rails 11 and 12 extending in the scanning direction. The carriage 2 is connected to a carriage motor 86 (see Figure 4) via a belt (not shown), and when the carriage motor 86 is driven, the carriage 2 moves in the scanning direction along the guide rails 11 and 12. Note that in the following explanation, the right and left sides of the scanning direction are defined as shown in Figure 1.

The subtank 3 is mounted on the carriage 2. The printer 1 includes a cartridge holder 13, in which four ink cartridges 14 are removably attached. The four ink cartridges 14 are aligned in the scanning direction, and from the right side in the scanning direction, they store black, yellow, cyan, and magenta ink. The subtank 3 is connected to the four ink cartridges 14 attached to the cartridge holder 13 via four tubes 15. This allows the four ink cartridges 14 to supply the above four colors of ink to the subtank 3.

The inkjet head 4 is mounted on the carriage 2 and connected to the lower end of the subtank 3. The inkjet head 4 is supplied with the four colors of ink from the subtank 3. The inkjet head 4 ejects ink from multiple nozzles 10 formed on its lower surface, the nozzle face 4a. More specifically, the multiple nozzles 10 are arranged in a transport direction perpendicular to the scanning direction to form nozzle rows 9, and on the nozzle face 4a, four nozzle rows 9 are aligned in the scanning direction. Black, yellow, cyan, and magenta inks are ejected from the multiple nozzles 10, starting with the nozzle row 9 on the right side of the scanning direction.

The platen 5 is positioned below the inkjet head 4 and faces the multiple nozzles 10. The platen 5 extends across the entire length of the recording paper P (the "ejection receiving medium" of this invention) in the scanning direction, supporting the recording paper P from below. The transport roller 6 is positioned upstream of the inkjet head 4 and platen 5 in the transport direction. The transport roller 7 is positioned downstream of the inkjet head 4 and platen 5 in the transport direction. The transport rollers 6 and 7 are connected to a transport motor 87 (see Figure 4) via gears and other devices (not shown). When the transport motor 87 is driven, the transport rollers 6 and 7 rotate, transporting the recording paper P in the transport direction.

The maintenance unit 8 includes a cap 71, a suction pump 72, and a waste liquid tank 73. The cap 71 is located to the right of the platen 5 in the scanning direction. When the carriage 2 is positioned at the maintenance position to the right of the platen 5 in the scanning direction, the multiple nozzles 10 face the cap 71.

The cap 71 can be raised and lowered by a cap lifting mechanism 88 (see Figure 4). When the carriage 2 is positioned in the maintenance position, where the multiple nozzles 10 and the cap 71 face each other, and the cap lifting mechanism 88 raises the cap 71 from the uncapped position, which is lower than the capped position, to the capped position, the upper end of the cap 71 comes into close contact with the nozzle surface 4a, covering the multiple nozzles 10. Note that the cap 71 does not necessarily have to cover the multiple nozzles 10 by coming into close contact with the nozzle surface 4a. For example, the cap 71 may also cover the multiple nozzles 10 by coming into close contact with a frame (not shown) or the like that is arranged around the nozzle surface 4a of the inkjet head 4.

The suction pump 72 is a tube pump or the like, and is connected to the cap 71 and waste liquid tank 73. In the maintenance unit 8, when the suction pump 72 is driven with the multiple nozzles 10 covered by the cap 71 as described above, a so-called suction purge (recovery operation) can be performed, in which ink is discharged from the inkjet head 4 through the multiple nozzles 10. The ink discharged by the suction purge is stored in the waste liquid tank 73.

For convenience, the cap 71 has been described as covering all of the nozzles 10 together, and ink within the inkjet head 4 is discharged from all of the nozzles 10 during suction purging. However, this is not limited to this. For example, the cap 71 may have separate portions covering the nozzles 10 that make up the rightmost nozzle row 9 that ejects black ink, and the nozzles 10 that make up the three leftmost nozzle rows 9 that eject color inks (yellow, cyan, and magenta ink), allowing either the black ink or the color ink within the inkjet head 4 to be selectively discharged during suction purging. Alternatively, for example, a separate cap 71 may be provided for each nozzle row 9, allowing ink to be discharged from the nozzles 10 individually for each nozzle row 9 during suction purging.

As shown in FIG. 2, a detection electrode 76 having a rectangular planar shape is disposed within the cap 71. The detection electrode 76 is connected to a high-voltage power supply circuit 77 via a resistor 79. A predetermined positive potential (e.g., approximately 600 V) is applied to the detection electrode 76 by the high-voltage power supply circuit 77 during the inspection drive described below. Meanwhile, the inkjet head 4 is held at ground potential. This creates a predetermined potential difference between the inkjet head 4 and the detection electrode 76. A signal processing circuit 78 is connected to the detection electrode 76. The signal processing circuit 78 includes a differentiation circuit and outputs a signal that has been processed, including differentiation, on the potential signal output from the detection electrode 76. In other words, the signal output from the signal processing circuit 78 is a voltage signal corresponding to the voltage of the detection electrode 76. However, the signal output from the signal processing circuit 78 may also be a current signal. In this embodiment, the combination of the detection electrode 76, high-voltage power supply circuit 77, signal processing circuit 78, and resistor 79 corresponds to the "signal output unit" of the present invention.

After positioning the carriage 2 in the maintenance position, a voltage is applied to the detection electrode 76 by the high-voltage power supply circuit 77. At this time, when the inspection drive described below is not being performed, the voltage of the signal output from the signal processing circuit 78 becomes voltage V0, as shown in Figures 3(a) and 3(b).

In this embodiment, the carriage 2 is positioned at the maintenance position, and while a voltage is applied to the detection electrode 76 by the high-voltage power supply circuit 77, inspection driving is performed, driving the inkjet head 4 to eject ink from the nozzles 10 toward the detection electrode 76.

If the nozzle 10 is not an abnormal nozzle with an abnormality in ink ejection, charged ink is ejected from the nozzle 10 when the test drive is performed. This causes the charged ink to approach the detection electrode 76, and the potential of the detection electrode 76 changes until the ink lands on the detection electrode 76. Then, after the charged ink lands on the detection electrode 76, the potential of the detection electrode 76 decays and returns to the potential before ink ejection.

At this time, the signal output from the signal processing circuit 78 (the "determination signal" of the present invention) rises from voltage V0 to voltage V1, which is greater than voltage V0, then drops to voltage V2, which is less than voltage V0, and then repeats this rise and fall while attenuating, before returning to voltage V0, as shown in Figure 3(a). As a result, the signal output from the signal processing circuit 78 becomes a signal whose maximum value is voltage V1 and whose minimum value is voltage V2.

On the other hand, if nozzle 10 is an abnormal nozzle, ink will not be ejected from nozzle 10 even when the test drive is performed. Therefore, the signal output from the signal processing circuit 78 will not change from voltage V0, as shown in Figure 3(b).

As such, in this embodiment, the signal output from the signal processing circuit 78 when the test drive is performed differs depending on whether the nozzle 10 is an abnormal nozzle. This is then used in this embodiment to determine whether the nozzle 10 is an abnormal nozzle, as described below.

<Printer electrical configuration>
Next, the electrical configuration of the printer 1 will be described. As shown in FIG. 4 , the printer 1 has a control unit 80. The control unit 80 includes a central processing unit (CPU) 81, a read-only memory (ROM) 82, a random access memory (RAM) 83, a flash memory (referred to as a "storage unit" in the present invention) 84, and an application-specific integrated circuit (ASIC) 85. The control unit 80 controls the operation of a carriage motor 86, inkjet head 4, a transport motor 87, a cap lifting mechanism 88, a suction pump 72, a high-voltage power supply circuit 77, a driver IC 89, and the like. In this embodiment, the control unit 80 controls the inkjet head 4 by controlling the driver IC 89. A determination signal is also input to the control unit 80 from the signal processing circuit 78.

In addition to the components described above, the printer 1 also has a clock unit 68, a display unit 69, an input unit 70, and a paper sensor 90. The clock unit 68 keeps time, and the control unit 80 receives a time signal indicating the time from the clock unit 68.

The display unit 69 is, for example, an LCD display provided on the housing of the printer 1. The control unit 80 controls the display unit 69 to display information necessary for the operation of the printer 1. The input unit 70 is, for example, buttons provided on the housing of the printer 1 or a touch panel provided on the display unit 69. The user can input signals to the control unit 80 by operating the input unit 70.

The paper sensor 90 is positioned between the inkjet head 4 and the transport roller 6 in the transport direction. It detects the recording paper P being transported by the transport roller 6 and outputs a signal to the control unit 80 indicating that the recording paper P has been transported.

For example, if the paper sensor 90 does not detect the recording paper P a predetermined time after the start of recording paper P transport during recording, this indicates a transport error, such as a jam, with the recording paper P. In this case, the ink in the multiple nozzles 10 may dry out, or the recording paper P may come into contact with the nozzles 10 and be damaged, resulting in abnormal ink ejection from the nozzles 10. If a transport error that causes such ink ejection abnormalities (the "device abnormality" of the present invention) occurs in the printer 1, the signal received by the control unit 80 from the paper sensor 90 (the signal received a predetermined time after the start of recording paper P transport) will be a signal other than the signal indicating the detection of the recording paper P, and this signal (the "device abnormality signal" of the present invention) indicates an apparatus abnormality. The paper sensor 90 in this embodiment corresponds to the "device abnormality output unit" of the present invention.

The control unit 80 may be configured so that only the CPU 81 performs various processes, or so that only the ASIC 85 performs various processes, or so that the CPU 81 and ASIC 85 work together to perform various processes. Furthermore, the control unit 80 may be configured so that a single CPU 81 performs processes independently, or so that multiple CPUs 81 share the processing. Furthermore, the control unit 80 may be configured so that a single ASIC 85 performs processes independently, or so that multiple ASICs 85 share the processing.

<When a device abnormality is detected>
Next, a description will be given of the control by the control unit 80, which indicates the operation when detecting whether an apparatus abnormality has occurred in the printer 1. In the printer 1, when the above-mentioned detection is made, the control unit 80 performs processing according to the flow of FIG.

Explaining the flow of Figure 5 in more detail, the control unit 80 determines whether or not an apparatus abnormality signal has been received (S101). That is, it determines whether or not the paper sensor 90 has output a signal indicating an apparatus abnormality signal to the control unit 80 due to an apparatus abnormality such as that described above. If an apparatus abnormality signal has not been received (S101: NO), S101 is repeated. If an apparatus abnormality signal has been received (S101: YES), the control unit 80 stores apparatus abnormality flag information in the flash memory 84 (S102). The apparatus abnormality flag information is flag information indicating that an apparatus abnormality such as that described above has occurred in the printer 1. This concludes the apparatus abnormality detection process flow.

<Standby control>
Next, a description will be given of the control by the control unit 80 during standby in the printer 1. During standby in the printer 1, the control unit 80 performs processing according to the flow in FIG.

Explaining the flow in Figure 6 in more detail, the control unit 80 determines whether the time signal received from the clock unit 68 indicates a predetermined time (the "first condition" of the present invention) (S201). In this embodiment, the predetermined time is set to early morning, such as 6:00 AM, but is not particularly limited to this.

If the time signal received from the clock unit 68 does not indicate that it is the specified time (S201: NO), the control unit 80 determines whether the number of sheets printed on the recording paper P has reached a specified cumulative number (the "first condition" of the present invention) (S202). On the other hand, if the time signal received from the clock unit 68 indicates that it is the specified time (S201: YES), the process proceeds to S205.

If the predetermined cumulative number is reached in S202 (S202: YES), the control unit 80 resets the cumulative number stored in the flash memory 84 to 0 (S203) and proceeds to S205. By resetting the cumulative number to 0 in this way, each time the predetermined cumulative number is reached, the control unit 80 triggers the process to proceed to the inspection process in S207.

On the other hand, if the predetermined cumulative number has not been reached (S202: NO), the control unit 80 determines whether device abnormality flag information is stored in the flash memory 84 (the "first condition" of the present invention) (S204). If device abnormality flag information is not stored (S204), the process returns to S201. On the other hand, if device abnormality flag information is stored (S204: YES), the process proceeds to S205.

In S205, the control unit 80 determines whether prohibition flag information is stored in the flash memory 84. Prohibition flag information is flag information indicating that a test pattern printing process has been executed to print a test pattern on recording paper P, and is flag information that prohibits certain operations (such as the inspection process and recovery process described below). If prohibition flag information is stored (S205: YES), the flow ends. If prohibition flag information is not stored (S205: NO), the control unit 80 erases the inspection flag information and recovery flag information described below from the flash memory 84 (S206). Next, the control unit 80 executes the inspection process (S207).

In S207, the control unit 80 places the inkjet head 4 in the maintenance position and sends a drive signal to the driver IC 89 to perform a test drive, which drives each of the multiple nozzles 10 to eject ink in turn. At this time, the control unit 80 stores test flag information in the flash memory 84 indicating that the test drive has been performed. The control unit 80 then determines whether a nozzle is abnormal based on the determination signal output from the signal processing circuit 78 for each nozzle 10 during the test drive. The control unit 80 then stores in the flash memory 84 all of the multiple nozzles 10 that have been determined to be abnormal. In other words, the information about the nozzle 10 that was previously abnormal, which is stored in the flash memory 84, is updated to the information about the nozzle 10 that is currently abnormal. This completes the flow in Figure 6.

<Control when printing test patterns>
Next, a description will be given of the control by the control unit 80 when printing a test pattern in the printer 1. In the printer 1, when printing the test pattern, the control unit 80 performs processing in accordance with the flow of FIG.

Explaining the flow in Figure 7 in more detail, the control unit 80 determines whether or not a test pattern recording command signal (a "test pattern formation instruction" in this invention) has been received through user operation of the input unit 70. The test pattern recording command signal is a signal for forming a predetermined test pattern on recording paper P. The test pattern is used by the user to visually check whether a nozzle is abnormal.

If a test pattern recording command signal has not been received (S301: NO), S301 is repeated. If a test pattern recording command signal has been received (S301: YES), the control unit 80 executes the test pattern printing process (S302).

In S302, the control unit 80 controls the transport motor 87 based on the test pattern recording command signal, causing the transport rollers 6 and 7 to transport the recording paper P to a position where the area of the recording paper P on which an image will be recorded in the first recording pass faces the multiple nozzles 10 of the inkjet head 4. The control unit 80 then controls the carriage motor 86 to move the carriage 2 in the scanning direction, while controlling the driver IC 89 to drive multiple drive elements, causing the inkjet head 4 to perform a recording pass in which ink is ejected from the multiple nozzles 10 toward the recording paper P.

After this, if recording on one sheet of recording paper P is not complete, the control unit 80 controls the transport motor 87 to cause the transport rollers 6 and 7 to transport the recording paper P a predetermined distance, and then performs another recording pass, repeating this operation until recording on one sheet of recording paper P is complete. If recording of an image on one sheet of recording paper P is complete, the control unit 80 controls the transport motor 87 to cause the transport rollers 6 and 7 to eject the recording paper P on which recording has been completed. At this time, the control unit 80 stores the cumulative number of prints on which images have been recorded in the flash memory 84.

Next, the control unit 80 determines whether a user determination signal (a "user determination instruction" of the present invention) has been received by the user operating the input unit 70 (S303). The user determination signal is a signal indicating the result of the user's confirmation of the test pattern formed on the recording paper P and their determination as to whether or not a recovery operation is necessary. If a user determination signal has not been input (S303: NO), S303 is repeated and input from the user is awaited. If a user determination signal has been received (S303: YES), the control unit 80 determines whether or not to perform a recovery operation based on the user determination signal (S304).

If it is determined that a recovery operation should be performed (S304: YES), the control unit 80 executes the recovery process (S305). In this embodiment, the recovery process involves the control unit 80 performing a suction purge. If it is determined that a recovery operation should not be performed (S304: NO), the process proceeds to S306.

Next, in S306, the control unit 80 stores the prohibition flag information in the flash memory 84. This completes the test pattern printing flow.

<Control during normal printing>
Next, we will explain the control by the control unit 80 during normal printing other than test pattern printing in the printer 1. When the printer 1 receives a recording command signal to execute normal printing, the control unit 80 performs processing according to the flow shown in Fig. 8. The recording command signal is a signal that instructs the printer 1 to form an image on recording paper P, and is sent to the control unit 80 from an external device or the like.

Explaining the flow in Figure 8 in more detail, the control unit 80 first determines whether a recording command signal has been received (S401). If a recording command signal has not been received (S401: NO), S401 is repeated. If a recording command signal has been received (S401: YES), the control unit 80 determines whether prohibition flag information is stored in the flash memory 84 (S402).

If prohibition flag information is stored (S402: YES), the control unit 80 increments the variable M by 1 (S403) and proceeds to S408. The variable M indicates the number of times the printing process has been executed since the prohibition flag information was stored. On the other hand, if prohibition flag information is not stored (S402: NO), the control unit 80 determines whether inspection flag information is stored in the flash memory 84 (S404).

If inspection flag information is not stored (S404: NO), S405, which is the same as S207 described above, is executed. On the other hand, if inspection flag information is stored (S404: YES), proceed to S406.

Next, the control unit 80 determines whether the number of abnormal nozzles stored in the flash memory 84 is equal to or greater than a threshold value (S406). This threshold value is used to execute recovery processing immediately before degradation of image quality becomes noticeable. If the number of abnormal nozzles is less than the threshold value (S406: NO), the process proceeds to S408. On the other hand, if the number of abnormal nozzles is equal to or greater than the threshold value (S406: YES), the control unit 80 executes recovery processing similar to S305 described above (S407). In other words, if the process proceeds from S406 to S407, recovery processing is automatically executed in S407. At this time, the control unit 80 stores recovery flag information in the flash memory 84 indicating that recovery processing has been executed. Recovery flag information is information indicating that recovery processing has been executed. In this embodiment, the automatic recovery processing is executed prior to the printing processing described below.

Next, the control unit 80 executes the printing process (S408). In S408, the control unit 80 controls the transport motor 87, carriage motor 86, and driver IC 89 based on the recording command signal, and records an image on one sheet of recording paper P in the same manner as in S302 described above (the "ejection operation" of the present invention). Then, when recording of the image on one sheet of recording paper P is complete, the control unit 80 controls the transport motor 87 to cause the transport rollers 6 and 7 to eject the recording paper P on which recording has been completed. At this time, the control unit 80 stores the cumulative number of prints on which images have been recorded on the recording paper P in the flash memory 84. This concludes the normal printing flow.

<Control for releasing the prohibition of recovery processing>
Next, a description will be given of recovery process cancellation control in the printer 1. In the printer 1, when the above-mentioned cancellation is cancelled, the control unit 80 performs the process according to the flow of FIG.

Explaining the flow of Figure 9 in more detail, the control unit 80 determines whether or not prohibition flag information is stored in the flash memory 84 (S501). If prohibition flag information is not stored (S501: NO), S501 is repeated. On the other hand, if prohibition flag information is stored (S501: YES), the control unit 80 determines whether or not the variable M is 1 (S502).

If the variable M is 1 (S502: YES), the printing process of S408 is executed after the prohibition flag information is stored, and the control unit 80 determines that the predetermined condition (the "second condition" of the present invention) is met. In this embodiment, the predetermined condition is that the printing process of S407 is executed and completed after the test pattern printing process is executed and the prohibition flag information is stored. As a result, the inspection process of S207 and the recovery process of S407 based on the inspection process of S207 are not executed at least until the predetermined condition is met after the test pattern printing process is executed. Then, when the control unit 80 determines that the predetermined condition is met, it erases the prohibition flag information from the flash memory 84 (S503). As a result, after the prohibition flag information is erased, the inspection process of S207 and the recovery process of S407 based on the inspection process can be executed. At this time, the control unit 80 also resets the variable M to 0.

On the other hand, if the variable M is 0 (S502: NO), the control unit 80 determines that the printing process of S407 has not been executed since the prohibition flag information was stored. The flow in FIG. 9 then ends.

As described above, with the printer 1 of this embodiment, regardless of whether or not recovery operation is performed based on the user's decision in response to the results of the test pattern formed on the recording paper P by the test pattern printing process (test pattern formation process), after the test pattern printing process has been performed, the automatic recovery process at S407 is not executed until at least a predetermined condition (second condition) is met. This makes it possible to reduce unnecessary ink consumption.

Furthermore, if the test pattern printing process of S302 is performed after S207 and before the printing process of S408, the automatic recovery process of S407 prior to the printing process will not be executed. This makes it possible to effectively reduce unnecessary ink consumption.

If S201 returns YES, the process proceeds to S207 after a predetermined time has elapsed, allowing inspection processing to begin. Also, if S202 returns YES, the process proceeds to S207 after the number of printed sheets reaches a predetermined cumulative number, allowing inspection processing to begin. Also, if S204 returns YES, the process proceeds to S207 after a device abnormality occurs in Printer 1, allowing inspection processing to begin.

Furthermore, if the process proceeds to S207 from either S201, S202, or S204, recovery processing can then be performed in S407 before the print process is performed in S408. This increases the reliability of image quality by automatically performing recovery processing before the print process is performed.

Furthermore, if it is determined in S402 that prohibition flag information has been stored after receiving a print command signal in S401, the inspection process in S405 before the printing process and the automatic recovery process in S407 are not executed. Furthermore, if it is determined that prohibition flag information has been stored when proceeding to S205 from either S201, S202, or S204, the inspection process in S207 is not executed. In this way, after the test pattern printing process has been performed, the inspection process itself is not executed until at least the above-mentioned predetermined condition (second condition) is met. This reduces ink consumption due to the inspection process.

Next, a printer according to the second embodiment will be described below with reference to Figures 10 and 11. The printer according to this embodiment differs from the printer 1 according to the first embodiment in the prohibition release control, but is otherwise substantially the same. Therefore, parts similar to those in the first embodiment are designated by the same reference numerals and will not be described again.

<Standby control>
In the printer of this embodiment, during the standby state, the control unit 80 performs processing according to the flow shown in FIG.

Explaining the flow in Figure 10 in more detail, after performing S201 described above, the control unit 80 proceeds to S205. If prohibition flag information is stored in S205 (S205: YES), the control unit 80 increments the variable N by 1 (S208) and ends the flow. The variable N indicates the number of times the predetermined time has been reached since the prohibition flag information was stored.

If prohibition flag information is not stored in S205 (S205: NO), the process proceeds to S206 and S207 described above, and the flow ends.

<Control for releasing the prohibition of recovery processing>
In the printer of this embodiment, the control unit 80 performs processing according to the flow shown in Fig. 11. Explaining the flow of Fig. 11 in more detail, the control unit 80 executes S601, which is similar to S501. If no prohibition flag information is stored (S601: NO), S601 is repeated. On the other hand, if prohibition flag information is stored (S601: YES), the control unit 80 determines whether the variable N is 1 (S602).

If the variable N is 1 (S602: YES), the control unit 80 determines that a predetermined condition (the "second condition" of the present invention) has been satisfied. In this embodiment, the predetermined condition is a condition in which S206 is not executed when a predetermined time has elapsed after the test pattern printing process has been executed and the prohibition flag information has been stored, i.e., the inspection process of S207 and the recovery process of S407 based on the inspection process of S207 are not executed. When the control unit 80 determines that the predetermined condition has been satisfied, it erases the prohibition flag information from the flash memory 84 (S603). As a result, S206 can be executed when a predetermined time has elapsed after the prohibition flag information has been erased, and the inspection process of S207 and the recovery process of S407 based on the inspection process of S207 can be executed. At this time, the control unit 80 also resets the variable N to 0.

On the other hand, if the variable N is 0 (S602: NO), the control unit 80 determines that it is the time from when the test pattern printing process was executed until the first specified time is reached. The flow in FIG. 11 then ends.

As described above, in the printer of this embodiment, the automatic recovery process in S407 is not executed until at least the first predetermined time is reached after the test pattern printing process is executed. This makes it possible to reduce unnecessary ink consumption. Furthermore, the same effect can be achieved in a configuration similar to that of the first embodiment. Note that by setting the variable N in S602 to 2 or more, the number of times the predetermined time is reached can be changed as desired, and the automatic recovery process in S407 can be prohibited from being executed until the predetermined number of times the predetermined time is reached.

Next, a printer according to the third embodiment will be described below with reference to Figure 12. The printer according to this embodiment differs from the printer according to the second embodiment in the prohibition release control, but is otherwise substantially the same. Therefore, parts similar to those in the second embodiment will be indicated by the same reference numerals and will not be described again.

<Control for releasing the prohibition of recovery processing>
In the printer of this embodiment, the control unit 80 performs processing according to the flow shown in FIG. 12. To explain the flow shown in FIG. 12 in more detail, the control unit 80 executes S701, which is similar to S601. If no prohibition flag information is stored (S701: NO), S701 is repeated. On the other hand, if prohibition flag information is stored (S701: YES), the control unit 80 determines whether a predetermined period (e.g., one day) has elapsed since the prohibition flag information was stored in the flash memory 84 (S702). In this embodiment, when the prohibition flag information is stored in S306, the control unit 80 also stores in the flash memory 84 the time information for storing the prohibition flag information based on the time signal from the clock unit 68.

If the predetermined period has elapsed (S702: YES), the control unit 80 determines that the predetermined condition (the "second condition" of the present invention) has been satisfied, as in the second embodiment. In this embodiment, the predetermined condition is a condition that prevents S206 from being executed when a predetermined time has elapsed for a predetermined period of time after the test pattern printing process is executed and the prohibition flag information is stored. In other words, the inspection process of S207 and the recovery process of S407 based on the inspection process of S207 are not executed. When the control unit 80 determines that the predetermined condition has been satisfied, it erases the prohibition flag information from the flash memory 84 (S703). As a result, after the prohibition flag information is erased, S206 can be executed when the predetermined time has elapsed, and the inspection process of S207 and the recovery process of S407 based on the inspection process of S207 can be executed. At this time, the control unit 80 also erases the time information.

On the other hand, if the specified period has not elapsed (S702: NO), the control unit 80 determines that the specified period has not elapsed since the prohibition flag information was stored. The flow in Figure 12 then ends.

As described above, in the printer of this embodiment, the automatic recovery process in S407 is not executed until at least a predetermined period of time has elapsed since the test pattern printing process was executed. This makes it possible to reduce unnecessary ink consumption. Furthermore, the same effect can be achieved in a configuration similar to that of the first embodiment.

Next, a printer according to the fourth embodiment will be described below with reference to Figures 13 to 15. The printer according to this embodiment is substantially the same as the printer 1 according to the first embodiment, except that it can execute inspection processing but does not execute recovery processing when prohibition flag information is stored in the flash memory 84. Therefore, parts similar to those in the first embodiment are designated by the same reference numerals and will not be described again.

<Standby control>
In the printer of this embodiment, during the standby state, the control unit 80 performs processing according to the flow shown in Fig. 13. Explaining the flow of Fig. 13 in more detail, the control unit 80 performs the above-mentioned steps S201 to S204, and then proceeds to S206. That is, in this embodiment, regardless of whether or not prohibition flag information is stored, if any of S201, S202, and S204 is YES, the process proceeds to S206 and S207. In this way, the inspection process is executed, and the flow ends.

<Control during normal printing>
In the printer of this embodiment, when a recording command signal for executing normal printing is received, the control unit 80 performs processing in accordance with the flow of FIG.

Explaining the flow in Figure 14 in more detail, after performing S401 described above, the process proceeds to S404 to S406 described above. In other words, in this embodiment, S402 and S403 described above are omitted. Then, if the answer is YES in S406, the control unit 80 determines whether prohibition flag information is stored in the flash memory 84 (S409).

If prohibition flag information is stored (S409: YES), the control unit 80 increments variable R by 1 (S410) and proceeds to S408. Variable R indicates the number of attempts to proceed from S406 to the recovery process of S407 since prohibition flag information was stored. On the other hand, if prohibition flag information is not stored (S409: NO), the control unit 80 proceeds to S407 and executes automatic recovery processing. Thereafter, the control unit 80 executes the print process of S408 and ends the flow for normal printing.

<Control for releasing the prohibition of recovery processing>
In the printer of this embodiment, the control unit 80 performs processing according to the flow shown in Fig. 15. Explaining the flow shown in Fig. 15 in more detail, the control unit 80 executes S801, which is the same as S501. If no prohibition flag information is stored (S801: NO), S801 is repeated. On the other hand, if prohibition flag information is stored (S801: YES), the control unit 80 determines whether the variable R is 1 (S802).

If variable R is 1 (S802: YES), the control unit 80 determines that a predetermined condition (the "second condition" of the present invention) has been met. In this embodiment, the predetermined condition is a condition in which the recovery process of S407 is not executed once (the "predetermined number of times" of the present invention) after the test pattern printing process is executed and the prohibition flag information is stored, i.e., the recovery process of S407 based on the inspection process of S207 is not executed once. When the control unit 80 determines that the predetermined condition has been met, it erases the prohibition flag information from the flash memory 84 (S803). As a result, after the prohibition flag information has been erased, the recovery process of S407 based on the inspection process of S207 can be executed. At this time, the control unit 80 also resets variable R to 0.

On the other hand, if the variable R is 0 (S802: NO), the control unit 80 determines that the recovery process of S407 has not been performed since the test pattern printing process was executed. The flow in FIG. 15 then ends.

As described above, in the printer of this embodiment, the automatic recovery process in S407 is not executed at least from the time the test pattern printing process is executed until the printer attempts to proceed to the recovery process in S407. In other words, the automatic recovery process is not executed once (a predetermined number of times) after the test pattern printing process is executed. This makes it possible to effectively reduce unnecessary ink consumption. Furthermore, the same effect can be achieved in a configuration similar to that of the first embodiment.

Next, a printer according to the fifth embodiment will be described below with reference to Figures 16 and 17. The printer according to this embodiment executes the test pattern inspection process after receiving a test pattern print command signal, and does not execute the recovery process of S407 while the number K of abnormal nozzles in the inspection processes of S207 and S405 is smaller than the number J of abnormal nozzles when the recovery process of S305 after the test pattern printing process is not executed. Other than this, the printer is essentially the same as the printer according to the fourth embodiment. Therefore, parts similar to those in the fourth embodiment are denoted by the same reference numerals and descriptions thereof will be omitted.

<Control when printing test patterns>
In the printer of this embodiment, when printing the test pattern, the control unit 80 performs processing according to the flow shown in Fig. 16. Explaining the flow in Fig. 16 in more detail, if the answer to S301 is YES, the control unit 80 performs the test pattern inspection process (S307). After this, the control unit 80 performs S302 to S304.

If the control unit 80 determines in S304 that recovery operation should not be performed (NO), it stores non-execution flag information indicating that recovery operation should not be performed in the flash memory 84 (S308). After this, the process proceeds to S306, where the flow for printing the test pattern ends.

<Control for releasing the prohibition of recovery processing>
In the printer of this embodiment, the control unit 80 performs processing according to the flow shown in Fig. 17. Explaining the flow shown in Fig. 17 in more detail, the control unit 80 executes S901, which is similar to S801. If prohibition flag information is not stored (S901: NO), S901 is repeated. On the other hand, if prohibition flag information is stored (S901: YES), the control unit 80 determines whether non-execution flag information is stored in the flash memory 84 (S902).

If no non-execution flag information is stored (S902: NO), the flow ends. On the other hand, if no non-execution flag information is stored (S902: YES), the control unit 80 determines whether the number K of abnormal nozzles based on the inspection processes of S207 and S405 is greater than the number J of abnormal nozzles based on the test pattern inspection process of S307 when the recovery process of S305 after the test pattern printing process is not executed (S903).

If K is greater than J (S903: YES), the control unit 80 determines that a predetermined condition (the "second condition" of the present invention) has been met. In this embodiment, the predetermined condition is a condition in which recovery processing is not executed while K is equal to or less than J, i.e., recovery processing of S407 based on the inspection processing of S207 and S405 is not executed. When the control unit 80 determines that the predetermined condition has been met, it erases the prohibition flag information from the flash memory 84 (S904). As a result, after the prohibition flag information has been erased, recovery processing of S407 based on the inspection processing of S207 and S405 can be executed. At this time, the non-execution flag information is also erased from the flash memory 84.

On the other hand, if K is equal to or less than J (S902: NO), the control unit 80 determines that the user has decided not to perform recovery processing. The flow in FIG. 17 then ends.

As described above, in the printer of this embodiment, the automatic recovery process in S407 is not executed until the number of abnormal nozzles K becomes greater than the number of abnormal nozzles J after the test pattern printing process has been executed. In other words, the user does not need to execute the recovery process until the number of abnormal nozzles J exceeds the number at which the user has determined that recovery processing is not necessary. As a result, it is possible to effectively reduce unnecessary ink consumption in accordance with the user's wishes. Furthermore, the same effect can be achieved in a configuration similar to that of the third embodiment.

In the above-described embodiments, the inspection flag information is stored in the flash memory 84 as a result of the inspection process in S207. However, it is also possible to determine whether an error has occurred during the inspection process and store the inspection flag information only if no error has occurred. For example, before performing the inspection drive during the inspection process, the high-voltage power supply circuit 77 may temporarily apply a voltage to the detection electrode 76 while the inkjet head 4 is positioned in the maintenance position to detect whether a leak current is flowing from the detection electrode 76 to the inkjet head 4. If no leak current is flowing, the inspection drive may be performed, as in the above-described inspection process, and a determination may be made as to whether the nozzle is abnormal based on the determination signal output from the signal processing circuit 78 for each nozzle 10. The inspection flag information may then be stored. On the other hand, if a leak current is flowing, the inspection drive may not be performed at this time, and the inspection process of S405 may be performed instead. Before performing the test drive, the noise signal output from the signal processing circuit 78 is acquired, and if the noise signal is within a predetermined range, test processing is performed in the same manner as the test processing described above. If the noise signal is so large that it exceeds the predetermined range, test drive is not performed at this time, and the test processing of S405 is performed instead.

In addition, in the above-described embodiments, whether or not an apparatus abnormality has occurred in the printer 1 is determined based on a signal received from the paper sensor 90. However, whether or not an apparatus abnormality has occurred in the printer 1 may be determined by detecting that the printer 1 has not been properly powered off based on a signal from an encoder that detects the position of the carriage 2 in the scanning direction or a signal from a position sensor that detects the position of the cap 71. Also, whether or not an apparatus abnormality has occurred in the printer 1 may be determined in response to the detection of a paper jam from a signal from the encoder that detects the position of the carriage 2 in the scanning direction. Furthermore, the printer 1 may be provided with a battery, and a power supply detection circuit may be provided that outputs an apparatus abnormality signal to the control unit 80 indicating an apparatus abnormality when the battery's charge level reaches a minimum. In this case, if the battery runs out, the power supply to the clock unit 68 is cut off, causing the clock unit 68 to lose track of time. This may result in an apparatus abnormality that prevents processing such as S201 from being executed properly. As a variant, if the printer 1 does not have a battery, the power supply detection circuit may be provided in the path through which power is supplied from the outlet to the control unit 80. The power supply detection circuit may then output a device abnormality signal to the control unit 80 when the power supply from the outlet to the control unit is interrupted.

The above describes preferred embodiments of the present invention, but the present invention is not limited to the above embodiments and various modifications are possible within the scope of the claims. In each of the above embodiments, it is sufficient that at least one of the processes of S201, S202, and S204, which trigger the control unit 80 to execute the inspection process of S207, can be executed.

In addition, while the recovery process in each of the above-described embodiments was performed after receiving a recording command signal, it may also be performed after the inspection process and before receiving a recording command signal. In this case, the process of S205 can be performed before the inspection process or between the inspection process and the recovery process. Even in this case, it is possible to restrict the execution of the recovery process or the inspection process and the recovery process until at least the predetermined condition (second condition) is met.

Furthermore, in the above-described embodiments, all nozzles 10 of the inkjet head 4 are driven for testing, but this is not limited to this. For example, testing may be performed on only some of the nozzles 10 of the inkjet head 4, such as every other nozzle 10 in each nozzle row 9, and the remaining nozzles 10 may be determined to be abnormal based on the determination signal output from the signal processing circuit 78 during the testing.

In addition, in the above-described embodiment, the signal processing circuit 78 outputs a signal indicating whether or not the nozzle is abnormal, depending on the potential of the detection electrode 76 when ink is ejected from the nozzle 10 toward the detection electrode 76, but this is not limited to this.

For example, a detection electrode extending vertically may be arranged, and a signal processing circuit may output a signal indicating whether or not the nozzle is abnormal, depending on the potential of the detection electrode when ink is ejected from the nozzle 10 so that it passes through an area facing the detection electrode. Alternatively, an optical sensor (the "signal output unit" of the present invention) may be provided to detect ink ejected from the nozzle 10, and the optical sensor may output a signal indicating whether or not the nozzle is abnormal.

Alternatively, as described in, for example, Japanese Patent No. 4929699, a voltage detection circuit (the "signal output unit" of the present invention) that detects changes in voltage when ink is ejected from the nozzles can be connected to the plate on which the nozzles of the inkjet head are formed, and a signal indicating whether or not the nozzle is abnormal can be output from the voltage detection circuit to the control unit 80.

Alternatively, for example, as described in Japanese Patent No. 6231759, the substrate of the inkjet head may be equipped with a temperature detection element (the "signal output unit" of the present invention). Then, after applying a first applied voltage to drive the heater to eject ink, a second applied voltage is applied to drive the heater so that ink is not ejected, and a signal indicating whether the nozzle 10 is an abnormal nozzle or not may be output based on the change in temperature detected by the temperature detection element from the application of the second applied voltage until a predetermined time has elapsed.

Furthermore, in the above example, a nozzle 10 that does not eject ink is determined to be an abnormal nozzle, but this is not limited to this. For example, a signal output unit may be provided that outputs a signal depending on whether the ink ejection direction from the nozzle 10 is normal, and a nozzle 10 with an abnormal ejection direction may be determined to be an abnormal nozzle based on the signal from this signal output unit.

In addition, a signal output unit may be provided that outputs a signal corresponding to the abnormal nozzle state other than the lack of ink ejection, and information regarding the abnormal nozzle state may be obtained based on the signal from the signal output unit. An abnormal nozzle state refers to, for example, an abnormal ink ejection direction, the generation of splashes, the presence of air bubbles, or clogging with paper dust. In this case, the inspection drive may apply pressure to the ink to the extent that it does not eject ink from the nozzle 10, causing the ink near the nozzle 10 to vibrate. Then, a signal corresponding to the vibration state of the ink near the nozzle 10 may be output from the signal output unit to obtain information regarding the abnormal nozzle state.

Furthermore, while suction purging was performed in the recovery process, this is not limited to this. For example, a pressure pump may be provided midway along the tube 15 connecting the subtank 3 and the ink cartridge 14. Alternatively, a pressure pump connected to the ink cartridge may be provided in the printer. Then, with the multiple nozzles 10 covered by the caps 71, the pressure pump may be driven to pressurize the ink in the inkjet head 4 and expel the ink from the inkjet head 4 through the nozzles 10, thereby performing so-called pressure purging. Note that when pressure purging is performed for each color, a separate pressure pump may be provided for each color, or a switching mechanism may be provided to switch the connection to the pressure pump.

Furthermore, during the purging process, both suction by the suction pump 72 and pressurization by the pressure pump may be performed.

Furthermore, the method of recovering abnormal nozzles is not limited to purging. For example, abnormal nozzles may be recovered by flushing, which causes the inkjet head 4 to eject ink from the nozzles 10. Alternatively, abnormal nozzles may be recovered by both purging and flushing. Alternatively, abnormal nozzles may be recovered by selectively performing either purging or flushing, depending on the number of abnormal nozzles, etc.

Furthermore, while the present invention has been described as being applied to a printer equipped with a so-called serial head that ejects ink from multiple nozzles while moving in the scanning direction together with the carriage, this is not limited to this. For example, the present invention can also be applied to a printer equipped with a so-called line head that extends the entire length of the recording paper P in the scanning direction.

Furthermore, while the present invention has been described as being applied to a printer that ejects ink from nozzles to record on recording paper P, it is not limited to this. It can also be applied to printers that record images on recording media other than recording paper, such as T-shirts, outdoor advertising sheets, cases for mobile devices such as smartphones, cardboard, and plastic components. It can also be applied to liquid ejection devices that eject liquids other than ink, such as liquid resins or metals.

1. Printer (liquid ejection device)
4. Inkjet head (liquid ejection head)
8 Maintenance unit (recovery means)
10 nozzle 68 clock unit 70 input unit 76 detection electrode (part of signal output unit)
77 High voltage power supply circuit (part of signal output section)
78 Signal processing circuit (part of the signal output section)
79 Resistor (part of signal output section)
80 Control unit 84 Flash memory (storage unit)
90 Paper sensor (device abnormality output section)

Claims (10)

a liquid ejection head having a plurality of nozzles for ejecting liquid;
a signal output unit that outputs a determination signal according to whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to confirm whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid;
a recovery means for performing a recovery operation to discharge liquid from the nozzle;
an input unit for a user to input a predetermined instruction;
a control unit,
The control unit
when a user inputs a test pattern formation instruction to the input unit to form a test pattern on an ejection receiving medium to confirm whether or not the nozzle is the abnormal nozzle, a test pattern formation process is executed to form the test pattern on the ejection receiving medium by ejecting liquid from the plurality of nozzles;
when a user inputs a user determination instruction to the input unit as to whether or not to execute the recovery operation corresponding to the test pattern formed on the ejection receiving medium by the test pattern formation process, determining whether or not to cause the recovery means to execute the recovery operation based on the user determination instruction;
performing the test drive after the first condition is satisfied, and when it is determined that the number of abnormal nozzles is equal to or greater than a threshold value based on the determination signal output from the signal output unit during the test drive, executing an automatic recovery process that causes the recovery means to perform the recovery operation;
A liquid ejection device characterized in that after the test pattern formation process is performed, the automatic recovery process is not executed until at least a second condition different from the first condition is met, regardless of whether the recovery operation based on the user's judgment instruction has been executed. a liquid ejection head having a plurality of nozzles for ejecting liquid;
a signal output unit that outputs a determination signal according to whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to confirm whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid;
a recovery means for performing a recovery operation to discharge liquid from the nozzle;
an input unit for a user to input a predetermined instruction;
a control unit,
The control unit
when a user inputs a test pattern formation instruction to the input unit to form a test pattern on an ejection receiving medium to confirm whether or not the nozzle is the abnormal nozzle, a test pattern formation process is executed to form the test pattern on the ejection receiving medium by ejecting liquid from the plurality of nozzles;
when a user inputs a user determination instruction to the input unit as to whether or not to execute the recovery operation corresponding to the test pattern formed on the ejection receiving medium by the test pattern formation process, determining whether or not to cause the recovery means to execute the recovery operation based on the user determination instruction;
performing the test drive after the first condition is satisfied, and when it is determined that the number of abnormal nozzles is equal to or greater than a threshold value based on the determination signal output from the signal output unit during the test drive, executing an automatic recovery process that causes the recovery means to perform the recovery operation;
after the test pattern forming process is performed, the automatic recovery process is not performed until at least a second condition different from the first condition is satisfied, regardless of whether the recovery operation based on the user determination instruction has been performed or not;
further comprising a clock unit that outputs a time signal indicating the time;
The liquid ejection device is characterized in that the first condition is that the time signal indicating a predetermined time is output from the clock unit. a liquid ejection head having a plurality of nozzles for ejecting liquid;
a signal output unit that outputs a determination signal according to whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to confirm whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid;
a recovery means for performing a recovery operation to discharge liquid from the nozzle;
an input unit for a user to input a predetermined instruction;
a control unit,
The control unit
when a user inputs a test pattern formation instruction to the input unit to form a test pattern on an ejection receiving medium to confirm whether or not the nozzle is the abnormal nozzle, a test pattern formation process is executed to form the test pattern on the ejection receiving medium by ejecting liquid from the plurality of nozzles;
when a user inputs a user determination instruction to the input unit as to whether or not to execute the recovery operation corresponding to the test pattern formed on the ejection receiving medium by the test pattern formation process, determining whether or not to cause the recovery means to execute the recovery operation based on the user determination instruction;
performing the test drive after the first condition is satisfied, and when it is determined that the number of abnormal nozzles is equal to or greater than a threshold value based on the determination signal output from the signal output unit during the test drive, executing an automatic recovery process that causes the recovery means to perform the recovery operation;
after the test pattern forming process has been performed, the automatic recovery process is not executed until at least a second condition different from the first condition is satisfied, regardless of whether the recovery operation based on the user determination instruction has been executed or not;
Further comprising a storage unit,
The control unit
storing in the storage unit a cumulative number of ejection receiving media on which images have been formed by an ejection operation in which liquid is ejected from the plurality of nozzles of the liquid ejection head toward the ejection receiving medium;
The liquid ejection apparatus according to claim 1, wherein the first condition is that the cumulative number of sheets stored in the storage unit reaches a predetermined number. a liquid ejection head having a plurality of nozzles for ejecting liquid;
a signal output unit that outputs a determination signal according to whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to confirm whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid;
a recovery means for performing a recovery operation to discharge liquid from the nozzle;
an input unit for a user to input a predetermined instruction;
A liquid ejection device including a control unit,
The control unit
when a user inputs a test pattern formation instruction to the input unit to form a test pattern on an ejection receiving medium to confirm whether or not the nozzle is the abnormal nozzle, a test pattern formation process is executed to form the test pattern on the ejection receiving medium by ejecting liquid from the plurality of nozzles;
when a user inputs a user determination instruction to the input unit as to whether or not to execute the recovery operation corresponding to the test pattern formed on the ejection receiving medium by the test pattern formation process, determining whether or not to cause the recovery means to execute the recovery operation based on the user determination instruction;
performing the test drive after the first condition is satisfied, and when it is determined that the number of abnormal nozzles is equal to or greater than a threshold value based on the determination signal output from the signal output unit during the test drive, executing an automatic recovery process that causes the recovery means to perform the recovery operation;
After the test pattern forming process is performed, the automatic recovery process is not performed until at least a second condition is satisfied,
further comprising an apparatus abnormality output unit that outputs an apparatus abnormality signal when an apparatus abnormality other than the abnormal nozzle occurs in the liquid ejection device;
The liquid ejection apparatus is characterized in that the first condition is that the apparatus abnormality signal is output from the apparatus abnormality output section. a liquid ejection head having a plurality of nozzles for ejecting liquid;
a signal output unit that outputs a determination signal according to whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to confirm whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid;
a recovery means for performing a recovery operation to discharge liquid from the nozzle;
an input unit for a user to input a predetermined instruction;
a control unit,
The control unit
when a user inputs a test pattern formation instruction to the input unit to form a test pattern on an ejection receiving medium to confirm whether or not the nozzle is the abnormal nozzle, a test pattern formation process is executed to form the test pattern on the ejection receiving medium by ejecting liquid from the plurality of nozzles;
when a user inputs a user determination instruction to the input unit as to whether or not to execute the recovery operation corresponding to the test pattern formed on the ejection receiving medium by the test pattern formation process, determining whether or not to cause the recovery means to execute the recovery operation based on the user determination instruction;
performing the test drive after the first condition is satisfied, and when it is determined that the number of abnormal nozzles is equal to or greater than a threshold value based on the determination signal output from the signal output unit during the test drive, executing an automatic recovery process that causes the recovery means to perform the recovery operation;
After the test pattern forming process is performed, the automatic recovery process is not performed until at least a second condition is satisfied,
Furthermore, the control unit
A liquid ejection device characterized in that, when performing an ejection operation in which the liquid ejection head ejects liquid from the multiple nozzles toward the ejection medium, if the number of abnormal nozzles based on the judgment signal output from the signal output unit during the inspection drive performed after the first condition is satisfied is equal to or greater than a threshold value, the automatic recovery process is executed prior to the ejection operation. The liquid ejection device described in claim 5, characterized in that the second condition is that if the test pattern formation process is performed after the test drive that is performed after the first condition is satisfied and before the ejection operation is performed, the execution of the ejection operation is terminated. a liquid ejection head having a plurality of nozzles for ejecting liquid;
a signal output unit that outputs a determination signal according to whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to confirm whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid;
a recovery means for performing a recovery operation to discharge liquid from the nozzle;
an input unit for a user to input a predetermined instruction;
a control unit,
The control unit
when a user inputs a test pattern formation instruction to the input unit to form a test pattern on an ejection receiving medium to confirm whether or not the nozzle is the abnormal nozzle, a test pattern formation process is executed to form the test pattern on the ejection receiving medium by ejecting liquid from the plurality of nozzles;
when a user inputs a user determination instruction to the input unit as to whether or not to execute the recovery operation corresponding to the test pattern formed on the ejection receiving medium by the test pattern formation process, determining whether or not to cause the recovery means to execute the recovery operation based on the user determination instruction;
performing the test drive after the first condition is satisfied, and when it is determined that the number of abnormal nozzles is equal to or greater than a threshold value based on the determination signal output from the signal output unit during the test drive, executing an automatic recovery process that causes the recovery means to perform the recovery operation;
After the test pattern forming process is performed, the automatic recovery process is not performed until at least a second condition is satisfied,
Furthermore, the control unit
The liquid ejection device is characterized in that, after the test pattern forming process has been performed, the test driving after the first condition is satisfied is not executed until at least the second condition is satisfied. a liquid ejection head having a plurality of nozzles for ejecting liquid;
a signal output unit that outputs a determination signal according to whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to confirm whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid;
a recovery means for performing a recovery operation to discharge liquid from the nozzle;
an input unit for a user to input a predetermined instruction;
a control unit,
The control unit
when a user inputs a test pattern formation instruction to the input unit to form a test pattern on an ejection receiving medium to confirm whether or not the nozzle is the abnormal nozzle, a test pattern formation process is executed to form the test pattern on the ejection receiving medium by ejecting liquid from the plurality of nozzles;
when a user inputs a user determination instruction to the input unit as to whether or not to execute the recovery operation corresponding to the test pattern formed on the ejection receiving medium by the test pattern formation process, determining whether or not to cause the recovery means to execute the recovery operation based on the user determination instruction;
performing the test drive after the first condition is satisfied, and when it is determined that the number of abnormal nozzles is equal to or greater than a threshold value based on the determination signal output from the signal output unit during the test drive, executing an automatic recovery process that causes the recovery means to perform the recovery operation;
After the test pattern forming process is performed, the automatic recovery process is not performed until at least a second condition is satisfied,
The liquid ejection apparatus according to claim 1, wherein the second condition is that the automatic recovery process is not executed a predetermined number of times after the test pattern formation process is executed. a liquid ejection head having a plurality of nozzles for ejecting liquid;
a signal output unit that outputs a determination signal according to whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to confirm whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid;
a recovery means for performing a recovery operation to discharge liquid from the nozzle;
an input unit for a user to input a predetermined instruction;
a control unit,
The control unit
when a user inputs a test pattern formation instruction to the input unit to form a test pattern on an ejection receiving medium to confirm whether or not the nozzle is the abnormal nozzle, a test pattern formation process is executed to form the test pattern on the ejection receiving medium by ejecting liquid from the plurality of nozzles;
when a user inputs a user determination instruction to the input unit as to whether or not to execute the recovery operation corresponding to the test pattern formed on the ejection receiving medium by the test pattern formation process, determining whether or not to cause the recovery means to execute the recovery operation based on the user determination instruction;
performing the test drive after the first condition is satisfied, and when it is determined that the number of abnormal nozzles is equal to or greater than a threshold value based on the determination signal output from the signal output unit during the test drive, executing an automatic recovery process that causes the recovery means to perform the recovery operation;
After the test pattern forming process is performed, the automatic recovery process is not performed until at least a second condition is satisfied,
The liquid ejection apparatus is characterized in that the second condition is that a predetermined period of time has elapsed since the test pattern formation process was performed. a liquid ejection head having a plurality of nozzles for ejecting liquid;
a signal output unit that outputs a determination signal according to whether or not the nozzle is an abnormal nozzle when the liquid ejection head is driven for inspection to confirm whether or not the nozzle is an abnormal nozzle having an abnormality in ejecting liquid;
a recovery means for performing a recovery operation to discharge liquid from the nozzle;
an input unit for a user to input a predetermined instruction;
a control unit,
The control unit
when a user inputs a test pattern formation instruction to the input unit to form a test pattern on an ejection receiving medium to confirm whether or not the nozzle is the abnormal nozzle, a test pattern formation process is executed to form the test pattern on the ejection receiving medium by ejecting liquid from the plurality of nozzles;
when a user inputs a user determination instruction to the input unit as to whether or not to execute the recovery operation corresponding to the test pattern formed on the ejection receiving medium by the test pattern formation process, determining whether or not to cause the recovery means to execute the recovery operation based on the user determination instruction;
performing the test drive after the first condition is satisfied, and when it is determined that the number of abnormal nozzles is equal to or greater than a threshold value based on the determination signal output from the signal output unit during the test drive, executing an automatic recovery process that causes the recovery means to perform the recovery operation;
After the test pattern forming process is performed, the automatic recovery process is not performed until at least a second condition is satisfied,
Further comprising a storage unit,
The control unit
when the test pattern formation instruction is input to the input unit by a user, before or after the test pattern formation process is executed, the inspection drive is performed, and the abnormal nozzle based on the determination signal output from the signal output unit during the inspection drive is stored in the storage unit as a test pattern abnormal nozzle,
A liquid ejection device characterized in that the second condition is that the number of abnormal nozzles based on the judgment signal output from the signal output unit during the inspection drive performed after the first condition is satisfied is greater than the number of abnormal nozzles for the test pattern when the recovery means is not caused to perform the recovery operation based on the user judgment instruction.