Droplet dispensing device and program

Abstract

The goal is to make missing dots less noticeable while keeping the amount of data required for ejection (the data used to instruct the nozzle to eject ink droplets) from becoming excessively large. [Solution] Five types of discharge signals are generated: a dot-unformed signal, a small dot signal, a medium dot signal, a large dot signal, and an extra-large dot signal. A first table is stored in which the values ​​of 2-bit discharge data, "00", "01", "10", and "11", are associated with the small dot signal, medium dot signal, and large dot signal, respectively. A second table is also stored in which the values ​​of small dot signals, medium dot signals, and extra-large dot signals are associated, respectively. If there are no abnormal nozzles, the discharge signal for each dot is selected and generated by referring to the first table from the discharge data values. If there are abnormal nozzles, the discharge signal for each dot is selected and generated by referring to the second table from the discharge data values.

Description

Technical Field

[0001] The present invention relates to a droplet discharge device that discharges droplets from nozzles, and to a program executed in an external device connected to the droplet discharge device.

Background Art

[0002] As an example of a droplet discharge device that discharges droplets from nozzles, Patent Document 1 describes a recording apparatus that performs recording by discharging ink from nozzles. In the recording apparatus of Patent Document 1, a line head has a plurality of nozzles arranged in a direction orthogonal to the conveyance direction of a recording medium. Then, when a discharge-defective nozzle is detected among the plurality of nozzles of the line head, the size of ink dots formed by ink discharged from nozzles other than the complementary nozzle adjacent to the discharge-defective nozzle is kept the same as in normal operation, and the size of ink dots formed by ink discharged from the complementary nozzle is made larger than in normal operation. Thereby, in Patent Document 1, dot missing in a region of the recording medium where an ink dot is to be formed by ink discharged from the discharge-defective nozzle is made less noticeable.

Prior Art Literature

Patent Literature

[0003]

Patent Literature 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] In the recording device of Patent Document 1, as described above, in order to control the size of the ink dots formed by the ink ejected from the compensating nozzle to be larger than normal when a faulty nozzle is detected, it is conceivable that the data used to instruct the line head to eject ink from the nozzles could take values ​​corresponding to the size of the ink dots ejected when no faulty nozzle is detected, and values ​​corresponding to the size of dots larger than these ink dots. However, in this case, the amount of data may become larger compared to the case where the data can only take values ​​corresponding to the size of the ink dots ejected when no faulty nozzle is detected.

[0005] The object of the present invention is to provide a droplet dispensing device that, when there is an abnormal nozzle with abnormal droplet dispensing, makes the absence of dots less noticeable, while also preventing an increase in the amount of dot data used to instruct the droplet dispensing head to dispense droplets from the nozzle, and a program that is executed in an external device connected to the droplet dispensing device. [Means for solving the problem]

[0006] The droplet dispensing device of the present invention comprises a head having a plurality of nozzles that dispense droplets corresponding to a plurality of types of dispensing signals with different droplet amounts, the dispensing signal corresponding to the amount of droplet that forms a single dot on the dispensing medium, a data receiving unit that receives dispensing data having a plurality of types of values ​​for selecting the dispensing signal from an external device, a signal receiving unit that receives an abnormal nozzle signal relating to an abnormal nozzle among the plurality of nozzles that has an abnormality in droplet dispensing, a storage unit that stores a table in which the values ​​of the dispensing data and the dispensing signals are associated, and a control unit, wherein the storage unit has a first table in which a first value, which is one of the plurality of types of values, is associated with a first dispensing signal, which is one of the plurality of types of dispensing signals, and the The control unit stores a second table, in which a value is one of several types of discharge signals and is associated with a second discharge signal having a larger droplet volume than the first discharge signal. The control unit performs a determination process to determine whether or not there is an abnormal nozzle based on the abnormal nozzle signal, and a discharge process to select and generate the discharge signal by referring to the table from the several types of values ​​when the data receiving unit receives the discharge data, and to drive the head using the generated discharge signal to discharge the droplet. If the determination process determines that there is no abnormal nozzle, the discharge process is executed by referring to the first table. If the determination process determines that there is an abnormal nozzle, the discharge process is executed by referring to the second table.

[0007] Furthermore, the droplet dispensing device of the present invention comprises a head having a plurality of nozzles that dispense droplets corresponding to a plurality of types of dispensing signals with different droplet amounts, the dispensing signal corresponding to the amount of droplet that forms a single dot on the dispensing medium, a signal receiving unit that receives an abnormal nozzle signal relating to an abnormal nozzle among the plurality of nozzles that has an abnormality in droplet dispensing, a storage unit that stores a table in which values ​​of dispensing data having a plurality of types of values ​​for selecting the dispensing signal are associated with the dispensing signal, and a control unit, wherein the storage unit comprises a first table in which a first value which is one of the plurality of types of values ​​is associated with a first dispensing signal which is one of the plurality of types of dispensing signals, and the first value which is one of the plurality of types of dispensing signals and The control unit stores a second table associated with a second discharge signal having a larger droplet volume than the first discharge signal, and is capable of generating multiple types of discharge signals. The control unit performs a data generation process to generate the discharge data, a determination process to determine whether or not there is an abnormal nozzle based on the abnormal nozzle signal, and a discharge process after the data generation process to select and generate the discharge signal by referring to the table from the multiple types of values, and to drive the head using the generated discharge signal to discharge the droplets. If the determination process determines that there is no abnormal nozzle, the discharge process is executed by referring to the first table, and if the determination process determines that there is an abnormal nozzle, the discharge process is executed by referring to the second table.

[0008] The present invention comprises a head having a plurality of nozzles that dispense droplets corresponding to a plurality of types of dispensing signals with different droplet amounts, the dispensing signal corresponding to the amount of droplets that form a single dot on the dispensing medium, a data receiving unit that receives dispensing data having a plurality of values ​​for selecting the dispensing signal from an external device, a signal transmitting unit that transmits an abnormal nozzle signal to the external device regarding an abnormal nozzle among the plurality of nozzles that has an abnormality in droplet dispensing, a recording unit that stores a table in which the values ​​of the dispensing data and the dispensing signals are associated, and a signal generating unit that generates a plurality of types of dispensing signals, wherein the storage unit has a first table in which a first value, which is one of the plurality of values, is associated with a first dispensing signal, which is one of the plurality of types of dispensing signals, and a second table in which the first value is associated with a second dispensing signal, which is one of the plurality of types of dispensing signals and has a larger droplet amount than the first dispensing signal. A program executed in the control unit of the external device connected to a droplet dispensing device that stores the discharge data, which causes the computer to perform a data transmission process that transmits the discharge data to the data receiving unit, a determination process that determines whether or not there is an abnormal nozzle based on the abnormal nozzle signal transmitted by the signal transmission unit, and a command transmission process that selects and generates the discharge signal by referring to the table from the multiple types of values ​​of the discharge data received by the data receiving unit, and transmits a discharge command to the droplet dispensing device that instructs the head to drive using the generated discharge signal to discharge the droplets, and if the determination process determines that there is no abnormal nozzle, the command transmission process is executed to transmit the discharge command instructing the first table to be referred to, and if the determination process determines that there is an abnormal nozzle, the discharge process is executed to transmit the discharge command instructing the second table to be referred to. [Effects of the Invention]

[0009] In this invention, if there is no abnormal nozzle, the dispensing process is performed by referring to a first table in which the first value is associated with the first dispensing signal. If there is an abnormal nozzle, the dispensing process is performed by referring to a second table in which the first value is associated with a second dispensing signal in which the droplet volume is greater than that of the first dispensing signal. This makes it possible to increase the size of the dot corresponding to the first value when there is an abnormal nozzle compared to when there is no abnormal nozzle, without changing the amount of data in the dispensing data. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of the printer according to the first embodiment. [Figure 2] This diagram illustrates the electrodes placed inside the cap, and the connection relationships between the electrodes and the high-voltage power supply circuit and signal processing circuit. [Figure 3] (a) is a diagram showing the signal output from the signal processing circuit when ink is ejected from the nozzle during the test drive, and (b) is a diagram showing the signal output from the signal processing circuit when ink is not ejected from the nozzle during the test drive. [Figure 4] This is a block diagram showing the electrical configuration of a printer. [Figure 5] This flowchart shows the processing flow during recording in the first embodiment. [Figure 6] (a) is a diagram illustrating the output signal, (b) is a diagram illustrating the first table, and (c) is a diagram illustrating the second table. [Figure 7] Figure 6 is a flowchart showing the flow of the output signal selection process. [Figure 8] (a) is a diagram illustrating the fill pattern recorded when there is no abnormal nozzle, (b) is a diagram illustrating the case where ink droplets are ejected in the same way as when there is an abnormal nozzle and a fill pattern is recorded, and (c) is a diagram illustrating the case where the size of adjacent dots is made larger than when there is an abnormal nozzle and a fill pattern is recorded. [Figure 9]It is a flowchart showing the flow of ejection signal selection processing in the second embodiment. [Figure 10] It is a flowchart showing the flow of ejection signal selection processing in the third embodiment. [Figure 11] It is a flowchart showing the flow of processing during recording in the fourth embodiment. [Figure 12] It is a flowchart showing the flow of processing during recording in the fifth embodiment. [Figure 13] It is a sequence diagram showing the flow of processing by a printer and an external device during recording in the sixth embodiment. [Figure 14] It is a diagram for explaining another example of the second table. [Figure 15] (a) is a diagram for explaining an example of generating seven types of ejection signals, (b) is a diagram for explaining a first table corresponding to the ejection signals of (a), and (c) is a diagram for explaining a second table corresponding to the ejection signals of (a). [Figure 16] (a) is a diagram for explaining an example of generating six types of ejection signals, (b) is a diagram for explaining a first table corresponding to the ejection signals of (a), and (c) is a diagram for explaining a second table corresponding to the ejection signals of (a). DETAILED DESCRIPTION OF THE INVENTION

[0011] First Embodiment Hereinafter, a preferred first embodiment of the present invention will be described.

[0012] Overall Configuration of Printer As shown in FIG. 1, a printer 1 (the "droplet ejection device" of the present invention) according to the first embodiment includes a carriage 2, a sub tank 3, an inkjet head 4 (the "head" of the present invention), a platen 5, conveyance rollers 6 and 7 (the "conveyance unit" of the present invention), a maintenance unit 8, and the like.

[0013] The carriage 2 is supported by two guide rails 11 and 12 that extend in the scanning direction. In the following description, the right and left sides in the scanning direction will be defined as shown in Figure 1. The carriage 2 is connected to the carriage motor 86 (see Figure 4) via a belt or the like (not shown). When the carriage motor 86 is driven, the carriage 2 moves in the scanning direction along the guide rails 11 and 12.

[0014] Sub-tank 3 is mounted on carriage 2. Printer 1 is equipped with a cartridge holder 13. Four ink cartridges 14 are removably mounted in cartridge holder 13. The four ink cartridges 14 mounted in cartridge holder 13 are aligned in the scanning direction, and from right to left in the scanning direction, they contain black, yellow, cyan, and magenta inks. The four ink cartridges 14 mounted in cartridge holder 13 are connected to sub-tank 3 via four tubes 15. This supplies the four colors of ink from the four ink cartridges 14 to sub-tank 3.

[0015] The inkjet head 4 is mounted on the carriage 2 and connected to the lower end of the sub-tank 3. The inkjet head 4 is supplied with the four colors of ink from the sub-tank 3. The inkjet head 4 also ejects ink droplets (the "droplets" of this invention) from a plurality of nozzles 10 formed on its lower surface, the nozzle surface 4a. More specifically, the plurality of nozzles 10 are arranged in the transport direction to form a nozzle row 9, and on the nozzle surface 4a, four rows of nozzle rows 9 are arranged in the scanning direction. From the plurality of nozzles 10, ink droplets of black, yellow, cyan, and magenta are ejected in order, starting from the nozzle row 9 on the right side in the scanning direction.

[0016] The platen 5 is positioned below the inkjet head 4 and faces multiple nozzles 10. The platen 5 extends along the entire length of the recording paper P in the scanning direction and supports 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 or the like (not shown). When the transport motor 87 is driven, the transport rollers 6 and 7 rotate, and the recording paper P is transported in the transport direction.

[0017] The maintenance unit 8 comprises a cap 71, a suction pump 72, and a waste liquid tank 73. The cap 71 is positioned to the right of the platen 5 in the scanning direction. When the carriage 2 is positioned in the maintenance position to the right of the platen 5 in the scanning direction, multiple nozzles 10 face the cap 71.

[0018] Furthermore, the cap 71 is connected to a cap lifting mechanism 88 (see Figure 4). When the cap lifting mechanism 88 is driven, the cap 71 moves up and down. With the carriage 2 positioned in the maintenance position described above, the cap 71 is facing the multiple nozzles 10. When the cap 71 is raised by the cap lifting mechanism 88, the upper end of the cap 71 comes into close contact with the nozzle surface 4a, and the multiple nozzles 10 are covered by the cap 71. When the cap 71 is lowered, the multiple nozzles 10 are not covered by the cap 71. The cap 71 is not limited to covering multiple nozzles 10 by being in close contact with the nozzle surface 4a. For example, the cap 71 may cover multiple nozzles 10 by being in close contact with a frame (not shown) or the like, which is arranged around the nozzle surface 4a of the inkjet head 4.

[0019] The suction pump 72 is a tube pump or the like and is connected to the cap 71 and the waste liquid tank 73. When the suction pump 72 is driven in the state with the cap 71 closed, the maintenance unit 8 can perform a so-called suction purge, which discharges ink from the inkjet head 4 through multiple nozzles 10. The ink discharged by the suction purge is stored in the waste liquid tank 73.

[0020] For convenience, the explanation here assumes that the cap 71 covers all nozzles 10 together, and that during suction purging, ink is discharged from all nozzles 10 within the inkjet head 4. However, this is not the only possible configuration. For example, the cap 71 may have separate parts: one covering multiple nozzles 10 that make up the rightmost nozzle row 9 that ejects black ink, and another covering multiple nozzles 10 that make up the leftmost three rows of nozzles 9 that eject color ink. This allows for selective discharge of either black ink or color ink within the inkjet head 4 during suction purging. Alternatively, for example, the cap 71 may be provided individually for each nozzle row 9, allowing for individual discharge of ink from each nozzle 10 during suction purging.

[0021] As shown in Figure 2, an electrode 76 having a rectangular planar shape is arranged inside the cap 71. The electrode 76 is connected to a high-voltage power supply circuit 77 via a resistor 79. The high-voltage power supply circuit 77 applies a predetermined voltage (for example, about 600V) to the electrode 76 when performing the inspection drive described later. Meanwhile, the inkjet head 4 is held at ground potential. This creates a predetermined potential difference between the inkjet head 4 and the electrode 76. A signal processing circuit 78 is connected to the electrode 76. The signal processing circuit 78 includes a differentiating circuit and outputs a signal (the "abnormal nozzle signal" of the present invention) corresponding to the voltage of the electrode 76. However, the signal output from the signal processing circuit 78 may be a current signal.

[0022] With the capped state described above, and with a voltage applied to the electrode 76 by the high-voltage power supply circuit 77, and without performing the test drive described later, the voltage of the signal output from the signal processing circuit 78 will be the voltage V0 shown in Figures 3(a) and (b).

[0023] Furthermore, in the first embodiment, with the cap in place, a voltage can be applied to the electrode 76 by the high-voltage power supply circuit 77, causing the inkjet head 4 to perform an inspection drive to eject ink droplets from the nozzle 10 toward the electrode 76.

[0024] When an ink droplet is ejected from the nozzle 10 by the test drive, the ink droplet ejected from the nozzle 10 becomes charged due to the potential difference between the electrode 76 and the inkjet head 4. As a result, the charged ink droplet approaches the electrode 76, and the potential of the electrode 76 changes until the ink droplet lands on the electrode 76. After the charged ink droplet lands on the electrode 76, the potential of the electrode 76 decays and returns to the potential V0 it was at before the ink droplet was ejected.

[0025] At this time, the signal output from the signal processing circuit 78 rises from voltage V0 to voltage V1 which is greater than voltage V0, then falls to voltage V2 which is less than voltage V0, and then returns to voltage V0 while repeatedly rising and falling with attenuation.

[0026] On the other hand, if no ink droplets are ejected from the nozzle 10 due to the test drive, the signal output from the signal processing circuit 78 hardly changes from the voltage V0, as shown in Figure 3(b).

[0027] Thus, in the first embodiment, the signal output from the signal processing circuit 78 differs depending on whether or not an ink droplet was ejected from the nozzle 10 by the test drive. In the first embodiment, this can be used to determine whether or not the nozzle 10 is a defective nozzle with an abnormality in ink droplet ejection.

[0028] In the first embodiment, a predetermined voltage is applied to the electrode 76, the inkjet head 4 is held at ground potential, and the signal processing circuit 78 is configured to output a signal corresponding to the voltage of the electrode 76. However, the invention is not limited to this configuration. Alternatively, the electrode 76 may be held at ground potential, and a predetermined voltage may be applied to the inkjet head 4 to create a potential difference between the electrode 76 and the inkjet head 4. The signal processing circuit 78 may then be connected to the inkjet head 4 and output a signal corresponding to the voltage of the inkjet head 4.

[0029] <Electrical configuration of the printer> Next, the electrical configuration of printer 1 will be described. As shown in Figure 4, printer 1 is equipped with a control unit 80. The control unit 80 consists of a CPU (Central Processing Unit) 81, ROM (Read Only Memory) 82, RAM (Random Access Memory) 83, flash memory 84 (the "storage unit" of the present invention), ASIC (Application Specific Integrated Circuit) 85, etc. The control unit 80 controls the operation of the carriage motor 86, inkjet head 4, transport motor 87, cap lifting mechanism 88, suction pump 72, high voltage power supply circuit 77, etc. The control unit 80 also receives signals from the signal processing circuit 78, etc. In the first embodiment, the part of the control unit 80 that receives signals from the signal processing circuit 78 corresponds to the "signal receiving unit" of the present invention.

[0030] In addition to the configuration described above, the printer 1 also includes a communication unit 89 (the "data receiving unit" of the present invention). The control unit 80 is connected to an external device 99 via the communication unit 89. The external device 99 is, for example, a PC or a smartphone, and has a control unit 98. The control unit 98 consists of a CPU, ROM, RAM, flash memory, etc. The communication unit 89 may be connected to the external device 99 by wire or by wireless connection. The communication unit 89 may be directly connected to the external device 99 or connected to the external device 99 via a network such as a LAN (Local Area Network).

[0031] Furthermore, the control unit 80 may perform various processing using only the CPU 81, or only the ASIC 85, or the CPU 81 and ASIC 85 may cooperate in performing various processing. Also, the control unit 80 may be performed by a single CPU 81 alone, or by multiple CPUs 81 sharing the processing. Similarly, the control unit 80 may be performed by a single ASIC 85 alone, or by multiple ASICs 85 sharing the processing. The same applies to the control unit 98.

[0032] <Processing during recording> Next, the processing of the control unit 80 when recording on the recording paper P in the printer 1 will be described. In the first embodiment, for example, when a user performs an operation to instruct the external device 99 to record on the recording paper P, the external device 99 transmits a recording command to the control unit 80 instructing it to record, and the control unit 80 receives this recording command. Then, when the control unit 80 receives a recording command, it processes the data according to the flow shown in Figure 5.

[0033] To explain the flow in Figure 5 in more detail, the control unit 80 first starts receiving ejection data from the external device 99 (S101). Here, the control unit 98 of the external device 99 performs appropriate processing on the image data of the image to be recorded, such as color conversion processing to convert RGB values ​​to CMYK values, to generate ejection data, and transmits the generated ejection data to the control unit 80 of the printer 1 following the recording command. The ejection data is data in which, for each of the multiple dots that form the image, the value will be one of four types: "00", "01", "10", or "11", depending on the presence or absence of the dot and the size of the dot. In other words, the ejection data is 2 bits of data for each of the multiple dots. Then, in S101, the control unit 80 starts receiving the above ejection data transmitted from the control unit 98 of the external device 99.

[0034] Next, the control unit 80 performs a nozzle inspection process (S102). In the nozzle inspection process, the control unit 80 puts the nozzles into a capping state and applies voltage to the electrodes 76 using the high-voltage power supply circuit 77, and then causes the inkjet head 4 to perform an inspection drive for each of the multiple nozzles 10. The control unit 80 then determines whether a nozzle 10 is an abnormal nozzle based on the signal from the signal processing circuit 78 when the inspection drive is performed, and stores the determination result for each nozzle 10 in the flash memory 84.

[0035] Next, the control unit 80 performs the paper feeding process (S103). In the paper feeding process, the control unit 80 controls a paper feeding mechanism and a transport motor 87 (not shown) to supply the recording paper P.

[0036] Next, the control unit 80 waits until it has finished receiving the ejection data corresponding to the recording path, which will be performed in S106 later (S104:NO). When it has finished receiving the ejection data corresponding to the recording path (S104:YES), it executes the ejection signal selection process (S105).

[0037] In this first embodiment, when the control unit 80 executes the recording path processing of S106, which will be described later, it can generate five types of ejection signals for driving the inkjet head 4, as shown in Figure 6(a): a dot non-formation signal, a signal for small dots, a signal for medium dots, a signal for large dots, and a signal for extra-large dots. Note that the waveforms of the five types of ejection signals shown in Figure 6(a) are just examples and are not limited to these.

[0038] The dot non-formation signal is a signal that prevents ink droplets from being ejected from nozzle 10. The small dot signal is a signal that causes ink droplets to be ejected from nozzle 10 to form small dots on the recording paper P. The medium dot signal is a signal that causes nozzle 10 to eject ink droplets in a larger volume than when the inkjet head 4 is driven by the small dot signal, in order to form medium dots that are larger than small dots on the recording paper P. The large dot signal is a signal that causes nozzle 10 to eject ink droplets in a larger volume than when the inkjet head 4 is driven by the medium dot signal, in order to form large dots that are larger than medium dots on the recording paper P. The extra-large dot signal is a signal that causes nozzle 10 to eject ink droplets in a larger volume than when the inkjet head 4 is driven by the large dot signal, in order to form extra-large dots that are larger than large dots on the recording paper P.

[0039] Furthermore, in the first embodiment, the flash memory 84 (the "storage unit" of the present invention) stores a first table as shown in Figure 6(b) and a second table as shown in Figure 6(c). The first and second tables are tables that associate the values ​​of the ejected data with the ejected signals.

[0040] In the first table, the four values ​​of the ejected data, "00", "01", "10", and "11", correspond to the dot-unformed signal, the signal for small dots, the signal for medium dots, and the signal for large dots, respectively. In the second table, the four values ​​of the ejected data, "00", "01", "10", and "11", correspond to the dot-unformed signal, the signal for small dots, the signal for medium dots, and the signal for extra-large dots, respectively. In the first embodiment, the value of the ejected data "11" corresponds to the "first value" of the present invention.

[0041] In the discharge signal selection process of S105, the control unit 80 determines how to select the discharge signal by performing processing according to the flow shown in Figure 7. Note that the processing shown in the flow shown in Figure 7 is performed individually for each nozzle row 9.

[0042] To explain the flow shown in Figure 7, the control unit 80 first determines whether or not there is an abnormal nozzle based on the information received from the signal processing circuit 78 and stored in the flash memory 84 during the nozzle inspection process in S101, regarding whether or not each of the multiple nozzles 10 of the inkjet head 4 is an abnormal nozzle (S201, the "determination process" of the present invention).

[0043] If there are no abnormal nozzles (S201:NO), the control unit 80 decides to select the discharge signal for all dots by referring to the first table from the values ​​of the discharge data (S204).

[0044] If there is an abnormal nozzle (S201:YES), the control unit 80 determines whether or not the discharge data indicates the formation of an abnormal nozzle dot, which is a dot corresponding to the abnormal nozzle (S202).

[0045] If the ejection data indicates that no abnormal nozzle dots will be formed (S202: NO), the control unit 80 decides to select the ejection signals for all dots by referring to the first table from the values ​​of the ejection data (S204).

[0046] If the discharge data indicates that an abnormal nozzle dot is formed (S202: YES), the control unit 80 determines whether or not the discharge data indicates that an adjacent dot is formed, which is a dot adjacent to the abnormal nozzle dot in the transport direction (S203). Here, adjacent dots are dots adjacent to the upstream side of the abnormal nozzle dot in the transport direction, and dots adjacent to the downstream side of the abnormal nozzle dot in the transport direction. Then, in S203, the control unit 80 determines that the discharge data indicates that an adjacent dot is formed if the discharge data indicates that at least one of the dots adjacent to the upstream side of the abnormal nozzle dot in the transport direction, and dots adjacent to the downstream side of the abnormal nozzle dot in the transport direction, is formed.

[0047] However, adjacent dots may also refer to dots adjacent to the upstream side in the transport direction of the abnormal nozzle dot. In this case, in S203, the control unit 80 determines that the discharge data indicates the formation of an adjacent dot if the discharge data indicates the formation of a dot adjacent to the upstream side in the transport direction of the abnormal nozzle dot. On the other hand, in S203, even if the discharge data indicates the formation of a dot adjacent to the downstream side in the transport direction of the abnormal nozzle dot, the control unit 80 determines that the discharge data indicates the formation of an adjacent dot if it indicates that it does not form a dot adjacent to the upstream side in the transport direction of the abnormal nozzle dot.

[0048] Alternatively, the adjacent dot may refer to a dot adjacent to the downstream side in the transport direction of the abnormal nozzle dot. In this case, in S203, the control unit 80 determines that the discharge data indicates the formation of an adjacent dot if the discharge data indicates the formation of a dot adjacent to the downstream side in the transport direction of the abnormal nozzle dot. On the other hand, in S203, even if the discharge data indicates the formation of a dot adjacent to the upstream side in the transport direction of the abnormal nozzle dot, the control unit 80 determines that the discharge data indicates the formation of an adjacent dot if it indicates that it does not form a dot adjacent to the downstream side in the transport direction of the abnormal nozzle dot.

[0049] If the ejected data indicates that adjacent dots do not form (S203: NO), the control unit 80 decides to select the ejection signals for all dots by referring to the first table from the values ​​of the ejected data (S204).

[0050] If the ejected data indicates that adjacent dots are formed (S203: YES), the control unit 80 decides to select the ejection signal for the adjacent dots by referring to the second table from the values ​​of the ejected data (S205), and decides to select the ejection signal for non-adjacent dots, which are dots other than adjacent dots, by referring to the first table (S206).

[0051] Returning to the flow in Figure 5, after the ejection signal selection process in S105, the control unit 80 executes the recording path process (S106). In the recording path process, the control unit 80 controls the carriage motor 86 to move the carriage 2 in the scanning direction and drives the inkjet head 4 to perform a recording path in which ink droplets are ejected from multiple nozzles 10. At this time, the control unit 80 refers to the table selected in S105, selects and generates an ejection signal according to the ejection data, and uses the generated ejection signal to drive the inkjet head 4 to eject ink droplets from multiple nozzles 10.

[0052] Next, the control unit 80 determines whether or not recording on the recording paper P is complete (S107). If recording on the recording paper P is not complete (S107: NO), the control unit 80 performs the transport process (S108) and returns to S104. In the transport process of S108, the control unit 80 controls the transport motor 87 to perform a transport operation in which the transport rollers 6 and 7 transport the recording paper P a predetermined distance. Here, the predetermined distance is, for example, a distance less than or equal to the length of the nozzle row 9 in the transport direction.

[0053] As a result, the recording path and the transport operation are performed alternately, and recording is carried out on the recording paper P. Also, if the transport distance of the recording paper P during the transport operation is the same as the length of the nozzle row 9 in the transport direction, each area of ​​the recording paper P is recorded in one recording pass. On the other hand, if the transport distance of the recording paper P during the transport operation is shorter than the length of the nozzle row 9 in the transport direction, each area of ​​the recording paper P is recorded in two or more recording passes.

[0054] Furthermore, in the first embodiment, corresponding to the fact that the ejection data is data for each recording pass, the ejection signal selection process in S105 is executed each time a recording pass and a transport operation are performed.

[0055] In the first embodiment, the combination of the ejection signal selection process in S105 and the recording path process and transport process, which are repeated alternately to enable recording on the recording paper P by alternating between the recording path and transport operation, corresponds to the "ejection process" of the present invention.

[0056] If recording on the recording paper P is complete (S107: YES), the control unit 80 performs paper ejection (S109). In the paper ejection process, the control unit 80 controls the transport motor 87 to transport the recording paper P in the transport direction on the transport rollers 6 and 7, thereby ejecting the recording paper P.

[0057] Next, the control unit 80 determines whether or not to record on the next recording sheet P (S110). Specifically, it determines whether or not it has received ejection data for recording on the next recording sheet P. If it is to record on the next recording sheet P (S110: YES), it returns to S103. If it is not to record on the next recording sheet P (S110: NO), it terminates the process.

[0058] <Effects> In the first embodiment, if an abnormal nozzle is present, the recording path processing is performed by referring to a first table in which the first value of the discharge data (e.g., "11") is associated with a large dot signal. On the other hand, if an abnormal nozzle is present, the discharge processing is performed by referring to a second table in which the first value is associated with an extra-large dot signal, which has a larger droplet volume than the large dot signal. This makes it possible to increase the size of the dot corresponding to the first value when an abnormal nozzle is present compared to when there is no abnormal nozzle, without changing the amount of discharge data.

[0059] Furthermore, in the first embodiment, the control unit 80 generates five types of output signals. In this case, unlike the first embodiment, if the output data can take on five different values ​​corresponding to the five types of output signals, the output data will be 3 bits of data.

[0060] In contrast, in the first embodiment, the discharge signal corresponding to the value "11" in the discharge data is changed depending on whether or not there is an abnormal nozzle. Therefore, it is sufficient to have a discharge data that can take on four different values ​​regardless of whether or not there is an abnormal nozzle. In other words, regardless of whether or not there is an abnormal nozzle, the discharge signal can be generated and recorded using 2 bits of discharge data.

[0061] Furthermore, in the first embodiment, the value "11" in the ejection data is associated with the large dot signal in the first table, and the value "11" in the ejection data is associated with the extra-large dot in the second table. Therefore, when there is an abnormal nozzle, an extra-large dot can be formed without increasing the amount of ejection data compared to when there is no abnormal nozzle, making it less noticeable that an abnormal nozzle dot has not been formed.

[0062] Furthermore, in the first embodiment, when the discharge data indicates the formation of both abnormal nozzle dots and adjacent dots, the discharge signal for non-adjacent dots is selected by referring to a first table from multiple types of values ​​in the discharge data, and the discharge signal for adjacent dots is selected by referring to a second table from multiple types of values ​​in the discharge data. This makes it possible to increase the size of adjacent dots set to the first value, making it less noticeable that abnormal nozzle dots have not been formed.

[0063] On the other hand, if there are no abnormal nozzles, the first table is referenced from multiple types of values ​​in the discharge data to select the discharge signal for all dots. Also, if the discharge data indicates that neither abnormal nozzle dots nor adjacent dots are formed, the first table is referenced from multiple types of values ​​in the discharge data to select the discharge signal for all dots. This prevents the size of the dots set to the first value from being unnecessarily large.

[0064] Here, we will explain with an example how the absence of abnormal nozzle dots can be made less noticeable. For example, consider the case where a fill pattern A is recorded, which is formed by multiple large dots lined up in the scanning direction and the transport direction, respectively, when there is no abnormal nozzle, as shown in Figure 8(a). In this case, unlike the first embodiment, if each dot D is made into a large dot when one nozzle 10 is an abnormal nozzle, as in the case when there is no abnormal nozzle, then, as shown in Figure 8(b), the abnormal nozzle dot D1, which would normally be formed as shown by the dashed line, is not formed, resulting in white streaks (areas without dots) extending in the scanning direction in the fill pattern A. In contrast, in the first embodiment, as shown in Figure 8(c), by making the adjacent dot D2 an extra-large dot that is larger in size than the large dot when there is no abnormal nozzle, the absence of dot D1 can be made less noticeable.

[0065] Here, we will explain the case where, despite the presence of a faulty nozzle, the ejection signal for adjacent dots is selected by referring to the first table. For example, depending on the ejection data, ink droplets may not be ejected over the entire area of ​​the recording paper P, and ink ejection from the faulty nozzle may be unnecessary. In this case, even with a faulty nozzle, the ejection signal for adjacent dots is selected by referring to the first table, not the second table.

[0066] [Second Embodiment] Next, a preferred second embodiment of the present invention will be described. The second embodiment also relates to a printer 1 similar to that of the first embodiment. In the second embodiment, as in the first embodiment, the control unit 80 performs processing according to the flow shown in Figure 5 when recording on the recording paper P. However, in the second embodiment, in the transport process of S106, the control unit 80 performs a transport operation in which the recording paper P is transported in the transport direction for a distance equal to the length of the nozzle row 9. In the second embodiment, the control unit 80 performs processing according to the flow shown in Figure 9 in the ejection signal selection process.

[0067] To explain the flow in Figure 9 in detail, the control unit 80 performs the same processing as S201 and S202, as in the first embodiment, in S301 and S302. Then, if there is no abnormal nozzle (S301: NO), and if there is an abnormal nozzle and the discharge data indicates that no abnormal nozzle dots will be formed (S301: YES, S302: NO), the control unit 80 decides, as in the first embodiment, to select the discharge signal for all dots by referring to the first table from the values ​​of the discharge data (S304).

[0068] If there is an abnormal nozzle and the discharge data indicates that an abnormal nozzle dot is formed (S301: YES, S302: YES), the control unit 80 determines whether or not the discharge data indicates that an adjacent nozzle dot is formed, which is a dot corresponding to a nozzle 10 adjacent to the abnormal nozzle in the transport direction (S303).

[0069] Here, adjacent nozzle dots refer to dots corresponding to nozzles 10 adjacent to the upstream side in the transport direction of the abnormal nozzle, and dots corresponding to nozzles 10 adjacent to the downstream side in the transport direction of the abnormal nozzle. Therefore, in S303, the control unit 80 determines that the discharge data indicates the formation of an adjacent nozzle dot if the discharge data indicates the formation of at least one of the dots corresponding to nozzles 10 adjacent to the upstream side in the transport direction of the abnormal nozzle, and dots corresponding to nozzles 10 adjacent to the downstream side in the transport direction of the abnormal nozzle.

[0070] However, the adjacent nozzle dot may also refer to a dot corresponding to a nozzle 10 adjacent to the upstream side in the transport direction of the abnormal nozzle. In this case, in S303, the control unit 80 determines that the discharge data indicates the formation of an adjacent nozzle dot if the discharge data indicates the formation of a dot corresponding to a nozzle 10 adjacent to the upstream side in the transport direction of the abnormal nozzle. On the other hand, in S303, even if the discharge data indicates the formation of a dot corresponding to a nozzle 10 adjacent to the downstream side in the transport direction of the abnormal nozzle, if the discharge data indicates that it does not form a dot corresponding to a nozzle 10 adjacent to the upstream side in the transport direction of the abnormal nozzle, the control unit 80 determines that the discharge data indicates that it does not form an adjacent nozzle dot.

[0071] Alternatively, the adjacent nozzle dot may be a dot corresponding to a nozzle 10 adjacent to the downstream side in the transport direction of the abnormal nozzle. In this case, in S303, the control unit 80 determines that the discharge data indicates the formation of an adjacent dot when the discharge data indicates the formation of a dot corresponding to a nozzle 10 adjacent to the downstream side in the transport direction of the abnormal nozzle. On the other hand, in S203, even if the discharge data indicates that a dot corresponding to a nozzle 10 adjacent to the abnormal nozzle on the upstream side in the transport direction will be formed, if it also indicates that a dot corresponding to a nozzle 10 adjacent to the abnormal nozzle on the downstream side in the transport direction will not be formed, the control unit 80 determines that the discharge data indicates that an adjacent nozzle dot will not be formed.

[0072] If the discharge data indicates that adjacent nozzle dots will not be formed (S303: NO), the control unit 80 decides to select the discharge signals for all nozzles 10 by referring to the first table from the values ​​of the discharge data (S304).

[0073] If the discharge data indicates that adjacent nozzle dots are formed (S303: YES), the control unit 80 decides to select the discharge signal for the adjacent nozzle by referring to the second table from the values ​​of the discharge data (S305), and decides to select the discharge signal for the nozzles 10 other than the adjacent nozzle by referring to the first table (S306).

[0074] <Effects> In the second embodiment, when the discharge data indicates the formation of both an abnormal nozzle dot and an adjacent nozzle dot, the discharge signal is selected for nozzles other than the adjacent nozzle by referring to the first table from multiple types of values ​​in the discharge data, and the discharge signal is selected for the adjacent nozzle by referring to the second table from multiple types of values ​​in the discharge data. In this case, compared to the case in the first embodiment where a table is selected for each adjacent dot individually, it is not necessary to select a table to refer to for each individual dot, and a table to refer to can be selected for each nozzle 10, thus reducing the complexity of control in the discharge process and enabling faster processing. In addition, the size of the adjacent nozzle dot set to the first value can be increased to make it less noticeable that no abnormal nozzle dots have been formed.

[0075] For example, in the second embodiment as well, when there is an abnormal nozzle and one nozzle 10 forms one raster line, the adjacent nozzle will always be the nozzle 10 that forms the dot adjacent to the dot that the abnormal nozzle would have formed. As shown in Figure 8(c), this makes it less noticeable that dot D1 is not formed.

[0076] On the other hand, if there are no abnormal nozzles, the system selects the discharge signal for all dots by referring to the first table from multiple types of discharge data values. Also, if the discharge data indicates that neither abnormal nozzle dots nor adjacent nozzle dots are formed, the system selects the discharge signal for all dots by referring to the first table from multiple types of discharge data values. This prevents the size of the dots set to the first value from being unnecessarily large.

[0077] [Third Embodiment] Next, a preferred third embodiment of the present invention will be described. The third embodiment also relates to a printer 1 similar to that of the first embodiment. In the third embodiment, as in the first embodiment, the control unit 80 processes data according to the flow shown in Figure 5 when recording data onto the recording paper P. However, in the third embodiment, the control unit 80 processes data according to the flow shown in Figure 10 during the ejection signal selection process.

[0078] To explain the flow in Figure 10 in detail, the control unit 80 performs the same processing as S201 and S202, as in the first embodiment, in S401 and S402. Then, if there is no abnormal nozzle (S401: NO), and if there is an abnormal nozzle and the discharge data indicates that no abnormal nozzle dots will be formed (S401: YES, S402: NO), the control unit 80 decides, as in the first embodiment, to select the discharge signal for all dots by referring to the first table from the values ​​of the discharge data (S403).

[0079] If there is an abnormal nozzle and the discharge data indicates that it will form an abnormal nozzle dot (S401:YES, S402:YES), the control unit 80 decides to select the discharge signals for all dots by referring to the second table from the values ​​of the discharge data (S404).

[0080] As a result, in the third embodiment, when the control unit 80 receives ejection data for each recording path, it selects an ejection signal for all dots in the recording path corresponding to the ejection data indicating that no abnormal nozzle dots will be formed, by referring to the first table from the values ​​of the ejection data. On the other hand, it selects an ejection signal for all dots in the recording path corresponding to the ejection data indicating that an abnormal nozzle dot will be formed, by referring to the second table from the values ​​of the ejection data.

[0081] <Effects> In the third embodiment, as described in the first embodiment, the ejection data is data for each recording pass, and the ejection signal selection process is executed each time a recording pass is performed. When the ejection data indicates the formation of an abnormal nozzle dot, the second table is referenced from the ejection data to select the ejection signal for each dot to be formed in the recording pass corresponding to that ejection data. This makes it possible to increase the size of the dot set to the first value, making it less noticeable that no abnormal nozzle dots have been formed.

[0082] On the other hand, if the ejection data indicates that no abnormal nozzle dots will be formed, the ejection signal for each dot to be formed in the recording path corresponding to that ejection data is selected by referring to the first table from the ejection data. This prevents the size of the dots set to the first value from being unnecessarily large.

[0083] [Fourth Embodiment] Next, a preferred fourth embodiment of the present invention will be described. The fourth embodiment also relates to a printer 1 similar to the first embodiment. However, in the fourth embodiment, when the control unit 80 records on the recording paper P, it processes according to the flow shown in Figure 11.

[0084] To explain the flow in Figure 11 in detail, the control unit 80 starts receiving ejection data (S501), similar to S101 in the first embodiment, then performs nozzle inspection processing similar to S101 in the first embodiment (S502), and subsequently performs paper feeding processing similar to S103 in the first embodiment (S503).

[0085] Next, the control unit 80 waits until it has finished receiving the ejection data corresponding to one sheet of recording paper P (S504: NO). When it has finished receiving the ejection data corresponding to one sheet of recording paper P (S504: YES), the control unit 80 executes the ejection signal selection process (S505). In the ejection signal selection process in S505, the control unit 80 executes the process according to the flow shown in Figure 10, as in the third embodiment. However, in the fourth embodiment, unlike the third embodiment, the ejection data is data for each sheet of recording paper P. In the fourth embodiment, in S403, it is decided to select the ejection signal by referring to the first table for all dots from the ejection data for the recording paper P to be recorded this time. Also, in S404, it is decided to select the ejection signal by referring to the second table for all dots from the ejection data for the recording paper P to be recorded this time.

[0086] After the ejection signal selection process in S505, the control unit 80 executes the processes in S506 to S510, which are the same as in S106 to S110 of the first embodiment. However, in the fourth embodiment, unlike the first embodiment, after the transport process in S508, the process returns to S506. That is, in the fourth embodiment, corresponding to the fact that the ejection data is data for each recording sheet P, when recording is performed consecutively on multiple recording sheets P, the ejection signal selection process in S505 is executed each time recording on one recording sheet P is completed.

[0087] <Effects> In the fourth embodiment, when ejection data for multiple recording sheets P is received consecutively, if the ejection data indicates the formation of abnormal nozzle dots, the ejection signal for each dot to be formed for recording on the corresponding recording sheet P is selected by referring to the second table from multiple types of values ​​of the ejection data. This makes it possible to increase the size of the dot set to the first value, making it less noticeable that no abnormal nozzle dots have been formed.

[0088] On the other hand, if the ejection data indicates that no abnormal nozzle dots will be formed, the ejection signal for each dot to be formed for recording on the recording paper P corresponding to the ejection data is selected by referring to the first table from multiple types of values ​​in the ejection data. This prevents the size of the dot set to the first value from being unnecessarily large.

[0089] Furthermore, in the fourth embodiment, in the discharge signal selection process of S505, the control unit 80 performs processing according to the flow shown in Figure 10, but in the discharge signal selection process of S505, the control unit 80 may also perform processing according to the flow shown in Figure 7 or Figure 9.

[0090] Furthermore, if the ejection signal selection process in S505 is performed according to the flow shown in Figure 9, and the transport process in S508 is performed to transport the recording paper P in the transport direction for a distance equal to the length of the nozzle row 9, then if the nozzle 10 furthest upstream in the transport direction among the multiple nozzles 10 constituting the nozzle row 9 is an abnormal nozzle, then the nozzle 10 furthest downstream in the transport direction among the multiple nozzles 10 constituting the nozzle row 9 may be designated as the adjacent nozzle, and the dot corresponding to this nozzle 10 may be designated as the adjacent nozzle dot, and the processing in S303 to S306 may be performed.

[0091] [Fifth Embodiment] Next, a preferred fifth embodiment of the present invention will be described. The fifth embodiment also relates to a printer 1 similar to the first to fourth embodiments. However, in the first to fourth embodiments, the control unit 80 receives ejection data following the record command, whereas in the fifth embodiment, the control unit 80 receives image data of the image to be recorded on the recording paper P following the record command. At this time, the control unit 80 may receive the record command and image data from an external device 99. Alternatively, if the printer 1 is configured to be able to accommodate a memory card, the control unit 80 may receive a record command and image data from the memory card based on an operation of an operation unit (not shown) provided on the printer 1 or an external device 99 by the user, while a memory card containing image data is inserted into the printer 1. Image data may also be received from an image reading device such as a scanner. In the fifth embodiment, when recording on the recording paper P, processing is performed according to the flow shown in Figure 12.

[0092] To explain the flow in Figure 12 in detail, the control unit 80 executes the ejection data generation process (S601, the "data generation process" of the present invention). In the ejection data generation process, the control unit 80 generates ejection data by performing appropriate processing on the received image data, such as a color conversion process that converts RGB values ​​to CMYK values.

[0093] Next, the control unit 80 performs a nozzle inspection process similar to that in S102 of the first embodiment (S602), and then performs a paper feeding process similar to that in S103 (S603). Subsequently, the control unit 80 waits until the generation of ejection data corresponding to the recording path is completed (S604: NO). When the generation of ejection data corresponding to the recording path is completed (S604: YES), the control unit 80 performs the processes S605 to S610 similar to those S105 to S110 of the first embodiment. At this time, in the ejection signal selection process of S605, the process is carried out according to one of the flows in Figures 7, 9, or 10, similar to any of the first to third embodiments.

[0094] <Effects> In the fifth embodiment, when there is no abnormal nozzle, the discharge signal is selected by referring to a first table in which the first value of the discharge data is associated with the large dot signal. On the other hand, when there is an abnormal nozzle, the discharge signal is selected by referring to a second table in which the first value is associated with an extra-large dot signal, which has a larger droplet volume than the large dot signal. This makes it possible to increase the size of the dot corresponding to the first value when there is an abnormal nozzle compared to when there is no abnormal nozzle, without changing the amount of discharge data.

[0095] [Sixth Embodiment] Next, a preferred sixth embodiment of the present invention will be described. In the sixth embodiment, when recording is performed in the printer 1, the control unit 80 of the printer 1 and the control unit 98 of the external device 99 perform the processing shown in the sequence diagram of Figure 13. In the sixth embodiment, when the user operates an operation unit (not shown) of the external device 99 and instructs recording to be made on the recording paper P, the processing shown in Figure 13 is started. In the sixth embodiment, the program installed in the external device 99 that causes the control unit 98 of the external device 99 to perform the processing shown in Figure 13 is the program of the present invention. Also, in the sixth embodiment, the communication unit 89 of the printer 1 serves as both the "data receiving unit" and the "signal transmitting unit" of the present invention. Furthermore, in the sixth embodiment, as in the first to fifth embodiments, the control unit 80 of the printer 1 generates an ejection signal, and the control unit 80 of the printer 1 that generates the ejection signal corresponds to the "signal generating unit" of the present invention.

[0096] To explain in detail the process shown in Figure 13, in the sixth embodiment, first, the control unit 98 of the external device 99 sends an abnormal nozzle information request command to the control unit 80 of the printer 1, requesting information on whether or not each of the multiple nozzles 10 of the inkjet head 4 is an abnormal nozzle (S701). When the control unit 80 of the printer 1 receives the abnormal nozzle information request command, it performs a nozzle inspection process similar to that in S101 of the first embodiment (S702), and based on the result, it sends an abnormal nozzle signal to the control unit 98 of the external device 99 indicating whether or not each of the multiple nozzles 10 of the inkjet head 4 is an abnormal nozzle (S703).

[0097] When the control unit 98 of the external device 99 receives an abnormal nozzle signal, it performs ejection data generation processing similar to S601 in the fifth embodiment (S704). Subsequently, the control unit 80 performs selection information generation processing (S705). In the selection information generation processing, based on the abnormal nozzle signal received from the control unit 80 of the printer 1, processing is performed according to a flow similar to any of Figures 7 to 9.

[0098] However, in the sixth embodiment, in steps S204-S206 of Figure 7, S304-S305 of Figure 8, and S403-S404 of Figure 9, instead of selecting a discharge signal by referring to the first or second table from the values ​​of the discharge data, selection information is generated to indicate that a discharge signal is selected by referring to the first or second table from the values ​​of the discharge data. Specifically, in steps S204-S206 of Figure 7, S304-S306 of Figure 8, and S403 of Figure 9, selection information is generated to indicate that a discharge signal is selected by referring to the first table from the values ​​of the discharge data, and in steps S205 of Figure 7, S305 of Figure 8, and S404 of Figure 9, selection information is generated to indicate that a discharge signal is selected by referring to the second table from the values ​​of the discharge data.

[0099] Next, the control unit 80 of the external device 99 transmits the ejection data generated in S704, the selection information generated in S705, and a recording command (the "ejection command" of the present invention) that instructs the printer 1 to perform recording based on these to the control unit 80 of the printer 1 (S706, the "command transmission process" of the present invention).

[0100] When the control unit 80 of printer 1 receives ejection data, selection information, and a recording command, it performs ejection signal selection processing (S707). In the ejection signal selection processing, the control unit 80 of printer 1 selects an ejection signal for each dot based on the selection information, by referring to at least one of the first table and the second table from the values ​​of the ejection data.

[0101] Next, the control unit 80 of the printer 1 performs recording processing (S708). In the recording processing, the control unit 80 of the printer 1 repeatedly performs the same recording path processing and transport processing as described in the first embodiment to record on the recording paper P. In addition, in the recording path processing, the inkjet head 4 is driven using the ejection signal selected in S707 for each dot to eject ink droplets from the nozzle 10.

[0102] <Effects> In the sixth embodiment, when there is no abnormal nozzle, the discharge signal is selected by referring to a first table in which the first value of the discharge data is associated with a large dot signal. On the other hand, when there is an abnormal nozzle, the discharge signal is selected by referring to a second table in which the first value is associated with an extra-large dot signal, which has a larger droplet volume than the large dot signal. This makes it possible to increase the size of the dot corresponding to the first value when there is an abnormal nozzle compared to when there is no abnormal nozzle, without changing the amount of discharge data.

[0103] [Differentiation] Although preferred first to sixth embodiments of the present invention have been described above, the present invention is not limited to the first to sixth embodiments, and various modifications are possible as long as they are within the scope of the claims.

[0104] In the first embodiment, the discharge signals for all non-adjacent dots were selected by referring to the first table, but this is not limited to that. For example, the discharge signals for some non-adjacent dots may be selected by referring to the first table, and the discharge signals for the remaining non-adjacent dots may be selected by referring to the second table.

[0105] In the second embodiment, the discharge signals for all non-adjacent nozzle dots were selected by referring to the first table, but are not limited to this. For example, the discharge signals for some non-adjacent nozzle dots may be selected by referring to the first table, and the discharge signals for the remaining non-adjacent nozzle dots may be selected by referring to the second table.

[0106] In the sixth embodiment, when the control unit 80 of the printer 1 receives a command requesting abnormal nozzle information from the control unit 98 of the external device 99, it performs a nozzle inspection process and sends an abnormal nozzle signal to the control unit 98 of the external device 99 based on the result, but it is not limited to this. For example, when the control unit 98 of the external device 99 receives a command requesting abnormal nozzle information, the control unit 80 of the printer 1 may send an abnormal nozzle signal to the control unit 98 of the external device 99 based on information stored in the flash memory 84 in the past regarding whether or not it is an abnormal nozzle.

[0107] In the first to sixth embodiments, the control unit 80 can generate five types of output signals: a dot-unformed signal, a signal for small dots, a signal for medium dots, a signal for large dots, and a signal for extra-large dots. In the first table, the four values ​​of the ejected data, "00", "01", "10", and "11", are associated with the dot-unformed signal, the small dot signal, the medium dot signal, and the large dot signal, respectively. In the second table, the four values ​​of the ejected data, "00", "01", "10", and "11", are associated with the dot-unformed signal, the small dot signal, the medium dot signal, and the extra-large dot signal, respectively. However, this is not the only way.

[0108] In Modification 1, as in the first to sixth embodiments, as shown in Figure 6(b), the values ​​"00", "01", "10", and "11" of the ejection data are associated with the dot-non-formation signal, the small dot signal, the medium dot signal, and the large dot signal, respectively, in the first table. On the other hand, as shown in Figure 14, in the second table, the values ​​"00", "01", "10", and "11" of the ejection data are associated with the dot-non-formation signal, the medium dot signal, the large dot signal, and the extra-large dot signal, respectively. In other words, in Modification 1, in addition to the value "11" of the ejection data, the values ​​"01" and "10" are also associated with ejection signals with a larger droplet volume in the second table than in the first table.

[0109] In Modification 2, as shown in Figure 15(a), the control unit 80 generates seven types of output signals as output signals: a dot-unformed signal, a first small dot signal, a second small dot signal, a first medium dot signal, a second medium dot signal, a large dot signal, and an extra-large dot signal. The dot-unformed signal, the large dot signal, and the extra-large dot signal are the same signals as those described in the first embodiment. The first small dot signal is the same signal as the small dot signal in the first embodiment. The first medium dot signal is the same signal as the medium dot signal in the first embodiment.

[0110] The second small dot signal is a signal that causes the nozzle 10 to eject ink droplets such that the amount of droplets is greater than when the inkjet head 4 is driven by the first small dot signal, and less than when the inkjet head 4 is driven by the first medium dot signal, thereby forming dots on the recording paper P that are larger than small dots and smaller than medium dots.

[0111] The second medium-dot signal is a signal that causes the nozzle 10 to eject ink droplets such that the amount of droplets is greater than when the inkjet head 4 is driven by the first medium-dot signal, and less than when the inkjet head 4 is driven by the large-dot signal, thereby forming dots on the recording paper P that are larger than medium dots but smaller than large dots.

[0112] Furthermore, as shown in Figure 15(b), in the first table, the values ​​"00", "01", "10", and "11" of the ejection data are associated with the dot-non-formation signal, the signal for the first small dot, the signal for the first medium dot, and the signal for the large dot, respectively. As shown in Figure 15(c), in the second table, the values ​​"00", "01", "10", and "11" of the ejection data are associated with the dot-non-formation signal, the signal for the second small dot, the signal for the second medium dot, and the signal for the extra-large dot, respectively. In other words, in the modified example 2, in addition to the value "11" of the ejection data, the values ​​"01" and "10" are also associated in the second table with ejection waveforms that have a larger droplet volume than in the first table.

[0113] In Modification 3, as shown in Figure 16(a), the control unit 80 generates five types of output signals as output signals: a dot-unformed signal, a small dot signal, a first medium dot signal, a second medium dot signal, and a large dot signal. The dot-unformed signal, the small dot signal, and the large dot signal are the same signals as those described in the first embodiment. The first medium dot signal is the same signal as the medium dot signal in the first embodiment.

[0114] The second medium-dot signal is a signal that causes the nozzle 10 to eject ink droplets such that the amount of droplets is greater than when the inkjet head 4 is driven by the first medium-dot signal, and less than when the inkjet head 4 is driven by the large-dot signal, thereby forming dots on the recording paper P that are larger than medium dots but smaller than large dots.

[0115] Furthermore, as shown in Figure 16(b), in the first table, the values ​​"00", "01", "10", and "11" of the ejection data are associated with the dot-free signal, the signal for small dots, the signal for the first medium dot, and the signal for large dots, respectively. As shown in Figure 16(c), in the second table, the values ​​"00", "01", "10", and "11" of the ejection data are associated with the dot-free signal, the signal for small dots, the signal for the second medium dot, and the signal for large dots, respectively. In other words, in Modification 3, only the value "10" is associated in the second table with an ejection waveform that produces a larger droplet volume than in the first table. Modification 3 demonstrates that in the second table, the ejection signal associated with the value that produces the largest droplet volume among the multiple types of ejection data is not necessarily limited to an ejection signal that produces a larger droplet volume than the ejection signal associated with that value in the first table.

[0116] Furthermore, the number of types of values ​​in the discharge data and the number of types of discharge signals generated by the control unit 80 are not limited to those described above. For example, if K is an integer greater than or equal to 1, the value of the discharge data may be 2 K The types are less than or equal to (2 KIt may be possible to generate more than 1) types of output signals.

[0117] The control unit 80 is (2 K When generating more than 1) types of output signals, if the output data can take the same number of values ​​as the number of types of output signals, the output data will be (K+1) bits or more. In contrast, if the values ​​of the output data are 2 K If the number of types is limited to a certain limit, and the discharge signal corresponding to the first value of the discharge data is changed depending on whether or not there is an abnormal nozzle, then regardless of whether or not there is an abnormal nozzle, the discharge signal can be (2) using discharge data of K bits or less. K +1) It is possible to select and record from more than one type of output signal.

[0118] Furthermore, the number of types of values ​​in the discharge data, and the number of types of discharge signals generated by the control unit 80, are as follows: K While there are fewer than two types, the control unit 80 is (2 K It is not necessary to satisfy the condition that it generates more than 1 type of output signal.

[0119] Furthermore, in the first to sixth embodiments, when the inkjet head 4 was driven for testing, it was determined whether or not ink was ejected normally from the nozzle 10 based on the ejection determination signal output from the signal processing circuit 78 in response to the change in voltage at the electrode 76 located inside the cap 71 from the nozzle 10, but the invention is not limited to this.

[0120] For example, instead of electrode 76, an electrode extending vertically and facing the space below nozzle 10 when carriage 2 is in the maintenance position may be provided. The signal processing circuit 78 may then output a signal corresponding to the change in voltage of the above electrode when inspection drive is performed with carriage 2 in the maintenance position.

[0121] Alternatively, for example, an optical sensor may be provided that directly detects the ink ejected from the nozzle 10 when the carriage 2 is in a predetermined position such as a maintenance position, and outputs a signal according to the detection result. Based on the signal output from this optical sensor, it may be determined whether or not the nozzle 10 is an abnormal nozzle.

[0122] Alternatively, for example, as described in Japanese Patent Publication No. 4929699, a voltage detection circuit that detects changes in voltage when ink is ejected from a nozzle may be connected to the plate on which the nozzles of the inkjet head are formed, and it may be determined whether a nozzle is an abnormal nozzle based on the signal output from the voltage detection circuit when the operation to eject ink from the nozzle is performed with the carriage moved to the inspection position.

[0123] Alternatively, for example, the substrate of the inkjet head may be equipped with a temperature sensing element, as described in Japanese Patent Publication No. 6231759. Then, after applying a first applied voltage to drive the heater for ink ejection, a second applied voltage may be applied to drive the heater to prevent ink ejection, and it may be determined whether the nozzle 10 is an abnormal nozzle based on the temperature change detected by the temperature sensing element during the period from when the second applied voltage is applied until a predetermined time has elapsed.

[0124] Alternatively, the printer 1 may record a test pattern to check whether each nozzle 10 is an abnormal nozzle, and determine whether or not it is an abnormal nozzle based on the recorded results of this test pattern. In this case, for example, the user may be instructed to operate an operation unit (not shown) of the printer 1 or an external device 99 based on the recorded results of the test pattern, thereby inputting a signal of the recorded test pattern result to the control unit 80. In this case, the operation unit (not shown) or communication unit 89 of the printer 1 corresponds to the "signal receiving unit" of the present invention.

[0125] Alternatively, if the printer 1 is equipped with a scanner that reads images recorded on recording paper P, the recorded test pattern may be scanned to input a signal representing the recording result of the test pattern. In this case, the part of the control unit 80 that receives signals from the scanner corresponds to the "signal receiving unit" of the present invention.

[0126] Furthermore, in the first to sixth embodiments, all nozzles 10 of the inkjet head 4 were driven for inspection to determine whether or not they were abnormal nozzles, but this is not the only way to do so. For example, a test drive may be performed on only some nozzles 10 of the inkjet head 4, such as every other nozzle 10 in each nozzle row 9, to determine whether or not they are abnormal nozzles. Then, for the remaining nozzles 10, it may be estimated whether or not they are abnormal nozzles based on the results of the determination for the aforementioned partial nozzles 10.

[0127] Furthermore, in the above example, we determined whether nozzle 10 is a defective nozzle based on whether or not an ink droplet was ejected from nozzle 10, but this is not the only way. For example, we may determine whether or not nozzle 10 is a defective nozzle based on the direction and speed of ink droplet ejection, etc.

[0128] Furthermore, while the above describes an example of applying the present invention to a printer equipped with a so-called serial head that ejects ink from multiple nozzles while moving in the scanning direction with the carriage, the invention 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 along the entire length of the recording paper in the scanning direction.

[0129] Furthermore, while the above description has focused on an example of applying the present invention to a printer that ejects ink from a nozzle to record on recording paper P, the invention 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 resin materials. It can also be applied to liquid dispensing devices that dispense liquids other than ink, such as liquid resin or metal. [Explanation of Symbols]

[0130] 1: Printer 2: Carriage 4: Inkjet head 6,7 Conveyor rollers 10 nozzles 80: Control Unit 89: Communications Department 99: External device

Claims

1. A head having multiple nozzles that dispense droplets corresponding to multiple types of dispensing signals with different droplet amounts, which are dispensing signals corresponding to the amount of liquid droplets that form a single dot on the dispensing medium, A data receiving unit that receives discharge data having multiple types of values ​​for selecting the aforementioned discharge signal from an external device, A signal receiving unit that receives an abnormal nozzle signal relating to an abnormal nozzle among the plurality of nozzles that has an abnormality in the discharge of the liquid droplets, The system comprises a storage unit that stores a table relating the values ​​of the discharge data to the discharge signals, and a control unit. The storage unit stores, as tables, a first table in which a first value, which is one of the multiple types of values, is associated with a first discharge signal, which is one of the multiple types of discharge signals, and a second table in which the first value is associated with a second discharge signal, which is one of the multiple types of discharge signals and has a larger droplet volume than the first discharge signal. The control unit, A determination process that determines whether or not there is an abnormal nozzle based on the abnormal nozzle signal, When the data receiving unit receives the discharge data, it selects and generates the discharge signal by referring to the table from the multiple types of values, and performs a discharge process to drive the head and discharge the droplet using the generated discharge signal. A droplet dispensing device characterized in that, if the determination process determines that there are no abnormal nozzles, the dispensing process is executed by referring to the first table, and if the determination process determines that there are abnormal nozzles, the dispensing process is executed by referring to the second table.

2. Let K be an integer greater than or equal to 1. The value of the aforementioned discharge data is 2 K The types are less than or equal to: The control unit is (2 K +1) The droplet dispensing device according to claim 1, characterized in that it is capable of generating more than one type of dispensing signal.

3. The control unit, The discharge signal that does not discharge a droplet, The discharge signal for forming small dots on the discharge medium, The discharge signal for forming medium dots larger than the small dots in the discharge medium, The discharge signal for forming a large dot larger than the medium dot in the discharge medium, The droplet dispensing device according to claim 2, characterized in that it can generate five types of dispensing signals, including a dispensing signal for forming extra-large dots larger than the large dots on the dispensing medium.

4. The multiple types of values ​​in the dot data are four types of values, including the first value. The first table is a table in which, of the four types of values, the first value corresponds to the discharge signal for forming the large dot, and the remaining three types of values ​​correspond to the discharge signal that does not discharge a droplet, the discharge signal for forming the small dot, and the discharge signal for forming the medium dot, respectively. The droplet dispensing device according to claim 3, characterized in that the second table is a table in which the first value is associated with the dispensing signal for forming the extra-large dot.

5. The head has a plurality of nozzles arranged in a first direction, The discharge data is data for selecting the discharge signal for each of the plurality of dots arranged in the first direction. The control unit, If the determination process determines that there is an abnormal nozzle, and the discharge data indicates that it forms both the dot corresponding to the abnormal nozzle and an adjacent dot adjacent to that dot in the first direction, The droplet dispensing device according to any one of claims 1 to 4, characterized in that, in the dispensing process, the device selects and generates the dispensing signal for at least one of the dots other than the adjacent dots by referring to the first table from the multiple types of values ​​of the dispensing data, and selects and generates the dispensing signal for at least the adjacent dots by referring to the second table from the multiple types of values ​​of the dispensing data.

6. The head has a plurality of nozzles arranged in a first direction, The discharge data is data for selecting the discharge signal for each of the plurality of dots arranged in the first direction. The control unit, If the determination process determines that there is an abnormal nozzle, and the discharge data indicates that it forms both the dot corresponding to the abnormal nozzle and the adjacent nozzle dot, which is the dot corresponding to the adjacent nozzle that is adjacent to the abnormal nozzle in the first direction, The droplet dispensing device according to any one of claims 1 to 5, characterized in that, in the dispensing process, the device selects and generates the dispensing signal for at least one nozzle other than the adjacent nozzle by referring to the first table from the multiple types of values ​​of the dot data, and selects and generates the dispensing signal for at least the adjacent nozzle by referring to the second table from the multiple types of values ​​of the dot data.

7. The head has a plurality of nozzles arranged in a first direction, A carriage equipped with the aforementioned droplet dispensing head and moving in a second direction intersecting the first direction, The system includes a transport unit that transports the discharged medium in the first direction, The control unit, By moving the carriage in the second direction and switching between a discharge path in which droplets are discharged from the plurality of nozzles onto the discharge medium by the droplet discharge head and a transport operation in which the transport unit transports the discharge medium, the dots are formed on the discharge medium. The discharge data is data for selecting the discharge signal for each of the plurality of dots arranged in the first and second directions formed by the discharge path. The control unit, If the above determination process determines that there is an abnormal nozzle, In the aforementioned discharge process, When the data receiving unit receives multiple discharge data for multiple discharge paths, If the discharge data indicates that the dot corresponding to the abnormal nozzle is not formed, the discharge signal for each dot to be formed in the discharge path corresponding to the discharge data is selected and generated by referring to the first table from the multiple types of values ​​of the discharge data. The droplet dispensing device according to any one of claims 1 to 4, characterized in that, if the dispensing data indicates the formation of the dot corresponding to the abnormal nozzle, the device selects and generates the dispensing signal for each dot formed in the dispensing path corresponding to the dispensing data by referring to the second table from the multiple types of values ​​of the dispensing data.

8. The control unit, If the above determination process determines that there is an abnormal nozzle, In the aforementioned discharge process, When the data receiving unit receives multiple discharge data for multiple discharge media, If the discharge data indicates that the dot corresponding to the abnormal nozzle will not be formed, the discharge signal for each dot to be formed on the discharge medium corresponding to the discharge data is selected and generated by referring to the first table from the multiple types of values ​​of the discharge data. The droplet dispensing device according to any one of claims 1 to 4, characterized in that, if the dispensing data indicates the formation of the dot corresponding to the abnormal nozzle, the device selects and generates the dispensing signal for each dot to be formed on the dispensing medium corresponding to the dispensing data by referring to the second table from the multiple types of values ​​of the dispensing data.

9. A head having multiple nozzles that dispense droplets corresponding to multiple types of dispensing signals with different droplet amounts, which are dispensing signals corresponding to the amount of liquid droplets that form a single dot on the dispensing medium, A signal receiving unit that receives an abnormal nozzle signal relating to an abnormal nozzle among the plurality of nozzles that has an abnormality in the discharge of the liquid droplets, A storage unit that stores a table in which values ​​of discharge data having multiple types of values ​​for selecting the discharge signal are associated with the discharge signal, It comprises a control unit and, The storage unit stores, as tables, a first table in which a first value, which is one of the multiple types of values, is associated with a first discharge signal, which is one of the multiple types of discharge signals, and a second table in which the first value is associated with a second discharge signal, which is one of the multiple types of discharge signals and has a larger droplet volume than the first discharge signal. The control unit, Multiple types of the aforementioned output signals can be generated, A data generation process that generates the aforementioned output data, A determination process that determines whether or not there is an abnormal nozzle based on the abnormal nozzle signal, After the data generation process, the following discharge process is performed: selecting and generating the discharge signal by referring to the table from the multiple types of values, and using the generated discharge signal to drive the head and discharge the droplets. A droplet dispensing device characterized in that, if the determination process determines that there are no abnormal nozzles, the dispensing process is executed by referring to the first table, and if the determination process determines that there are abnormal nozzles, the dispensing process is executed by referring to the second table.

10. A program executed in the control unit of an external device connected to a droplet dispensing device, comprising: a head having a plurality of nozzles that dispense droplets corresponding to a plurality of types of dispensing signals with different droplet amounts, the dispensing signal corresponding to the amount of droplets that form a single dot on the dispensing medium; a data receiving unit that receives dispensing data having a plurality of values ​​for selecting the dispensing signal from an external device; a signal transmitting unit that transmits an abnormal nozzle signal to the external device regarding an abnormal nozzle among the plurality of nozzles that has an abnormality in droplet dispensing; a recording unit that stores a table in which the values ​​of the dispensing data and the dispensing signals are associated; and a program executed in the control unit of an external device connected to a droplet dispensing device, wherein the storage unit stores as the table a first table in which a first value, which is one of the plurality of values, is associated with a first dispensing signal, which is one of the plurality of types of dispensing signals; and a second table in which the first value is associated with a second dispensing signal, which is one of the plurality of types of dispensing signals and has a larger droplet amount than the first dispensing signal. On the computer, A data transmission process that transmits the discharged data to the data receiving unit, A determination process that determines whether or not there is an abnormal nozzle based on the abnormal nozzle signal transmitted by the signal transmission unit, The command transmission process involves selecting and generating the discharge signal by referring to the table from the multiple types of values ​​of the discharge data received by the data receiving unit, and sending a discharge command to the droplet discharge device that instructs the head to be driven using the generated discharge signal to discharge the droplets, If the determination process determines that there are no abnormal nozzles, the command transmission process is executed to transmit the discharge command instructing the system to refer to the first table. The program is characterized in that, if the determination process determines that there is an abnormal nozzle, it causes the program to execute the discharge process which sends a discharge command instructing the program to refer to the second table.

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