JP5088708B2 - Liquid discharge inspection apparatus and liquid discharge inspection method - Google Patents

Description

  The present invention relates to a liquid ejection inspection apparatus, a liquid ejection inspection method, a liquid ejection apparatus, an ink jet printer, a program, and a liquid ejection system that perform a liquid ejection inspection from a liquid ejection section.

As a liquid ejecting apparatus, an ink jet printer that performs printing by ejecting ink onto various media such as paper, cloth, and film is known. This ink jet printer performs color printing by ejecting ink of each color such as cyan (C), magenta (M), yellow (Y), and black (K) to form dots on a medium. Ink is ejected by nozzles.
However, in such an ink jet printer, the nozzles may be clogged due to ink sticking or the like, and the ink may not be ejected normally. Thus, when ink is not ejected normally from the nozzles, dots cannot be formed properly on the medium, which causes a problem that images are not printed neatly. For this reason, it is necessary to periodically inspect the ejection of the nozzles to inspect whether the ink is ejected normally.

  In view of this, various methods for inspecting whether ink is normally ejected from nozzles have been proposed. Specifically, a method for inspecting ink ejection failure by detecting whether or not the ink ejected from the nozzle blocks a laser beam has been proposed (see Patent Document 1).

JP 2002-361863 A

However, such an inspection method requires a large-scale laser irradiation device to irradiate a laser beam, and it is extremely difficult to secure a space for installing such a laser irradiation device inside the printer. There was also a problem that caused a significant cost increase. For this reason, there has been a demand for a more compact and compact discharge inspection apparatus that does not require much installation space and does not cause a significant increase in cost.
The present invention has been made in view of such circumstances, and an object of the present invention is to enable a discharge inspection to be easily performed in a discharge portion of a liquid such as ink.

The main invention for achieving the object includes a liquid ejection unit that ejects liquid, an electrode unit that is provided in a non-contact state with the liquid ejection unit, a potential detection unit that detects a potential of the electrode unit, A liquid discharge inspection apparatus that performs an operation of discharging the liquid from the liquid discharge portion toward the electrode portion, detects a change in the potential at the electrode portion, and performs a discharge inspection at the liquid discharge portion In the liquid discharge inspection apparatus, a cycle of the drive signal for discharging the liquid when performing the discharge inspection is shorter than a cycle of the drive signal for discharging the liquid when performing printing. .
A liquid discharge unit that discharges the liquid; an electrode unit that is provided in a non-contact state with the liquid discharge unit; and a potential detection unit that detects a potential of the electrode unit. A liquid ejection inspection apparatus that performs an operation of ejecting the liquid toward an electrode portion, detects a change in the potential at the electrode portion, and performs an ejection inspection at the liquid ejection portion, and performs the ejection inspection. In some cases, the liquid discharge inspection apparatus may be configured such that the interval at which the liquid is discharged is shorter than the interval at which the liquid is discharged when printing is performed.
Alternatively, in a liquid ejection inspection apparatus that performs a liquid ejection inspection in the liquid ejection section, the liquid ejection inspection apparatus includes an electrode section provided in a non-contact state with the liquid ejection section, and the liquid is ejected from the liquid ejection section toward the electrode section. When a current path is formed by the liquid discharged and discharged from the liquid discharge section between the liquid discharge section and the electrode section, it is determined that there is discharge, and the current path is not formed In this case, a liquid discharge inspection apparatus characterized by determining that there is no discharge may be used .

  Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

  According to the present invention, the discharge inspection of the liquid discharge unit can be easily performed.

The perspective view of an inkjet printer. The internal block diagram of an inkjet printer. Sectional drawing which shows the conveyance part of an inkjet printer. The block block diagram which shows the system configuration | structure of an inkjet printer. The top view which shows the nozzle of a head. The circuit diagram which shows one Embodiment of a nozzle drive circuit. 4 is a timing chart of an original signal ODRV, a print signal PRT (i), and a drive signal DRV (i) showing operations of the drive signal generator. 6 is a flowchart for explaining an example of a processing flow of printing processing. Explanatory drawing explaining the liquid discharge test | inspection apparatus of this embodiment. Explanatory drawing explaining the test | inspection method of the liquid discharge test | inspection apparatus of this embodiment. FIG. 11A is a plan view of the electrode portion, and FIG. 11B is a side view of the electrode portion. Explanatory drawing explaining the installation position of an electrode part. Explanatory drawing explaining the positional relationship of the electrode part and nozzle at the time of a discharge test | inspection. Explanatory drawing explaining the drive signal of a nozzle, and the output signal of a detection part. The flowchart explaining one Embodiment of a test | inspection procedure. The flowchart explaining one Embodiment of a test | inspection procedure. 9 is a flowchart for explaining a discharge inspection procedure for each nozzle row. Sectional drawing which showed one Embodiment of the structure of a head. The perspective view explaining one Embodiment of the cleaning mechanism of an electrode plate. FIG. 19A is an explanatory diagram for explaining a state before cleaning, and FIG. 19B is an explanatory diagram for explaining a state after cleaning. The perspective view explaining other embodiment of the cleaning mechanism of an electrode plate. 21A, 21B, and 21 are plan views showing other embodiments of the electrode portion of the present invention. 1 is a perspective view illustrating an embodiment of a liquid ejection system according to the present invention. The block block diagram which shows the structure of the liquid discharge system of FIG.

=== Summary of disclosure ===
At least the following matters will become apparent from the description of the present specification and the accompanying drawings.

A liquid ejection unit that ejects liquid; an electrode unit that is provided in a non-contact state with the liquid ejection unit; and a potential detection unit that detects a potential of the electrode unit, the liquid ejection unit to the electrode unit A liquid discharge inspection apparatus that performs an operation of discharging the liquid toward the liquid, detects a change in the potential in the electrode unit, and performs a discharge inspection in the liquid discharge unit. The liquid discharge inspection apparatus, wherein a cycle of the drive signal for discharging the liquid is shorter than a cycle of the drive signal for discharging the liquid when performing printing.
A liquid discharge unit that discharges the liquid; an electrode unit that is provided in a non-contact state with the liquid discharge unit; and a potential detection unit that detects a potential of the electrode unit. A liquid ejection inspection apparatus that performs an operation of ejecting the liquid toward an electrode portion, detects a change in the potential at the electrode portion, and performs an ejection inspection at the liquid ejection portion, and performs the ejection inspection. The liquid discharge inspection apparatus, wherein the interval at which the liquid is sometimes discharged is shorter than the interval at which the liquid is discharged when printing is performed.
In these liquid discharge inspection apparatuses, the discharge inspection may be performed when the medium is fed. The liquid discharge unit may include a first nozzle and a second nozzle, and the discharge inspection at the first nozzle and the discharge inspection at the second nozzle may be performed simultaneously.
In a liquid discharge inspection apparatus for performing a liquid discharge inspection in a liquid discharge unit,
An electrode part provided in a non-contact state with the liquid ejection part;
When the liquid is discharged from the liquid discharge portion toward the electrode portion, and a current path is formed between the liquid discharge portion and the electrode portion by the liquid discharged from the liquid discharge portion, It is determined that there is a discharge,
A liquid ejection inspecting apparatus, wherein when the current path is not formed, it is determined that there is no ejection.
In such a liquid discharge inspection apparatus, the discharge inspection of the liquid discharge unit can be easily performed.

  In such a liquid ejection inspection apparatus, the current path may be formed by continuously ejecting liquid droplets as the liquid from the liquid ejection section toward the electrode section. Thus, by discharging liquid droplets continuously from the liquid discharge section, a current path can be easily formed, and the presence or absence of liquid discharge in the liquid discharge section can be checked.

  Further, such a liquid discharge inspection apparatus may include a detection unit for detecting whether or not the current path is formed between the liquid discharge unit and the electrode unit. If such a detection unit is provided, it is possible to easily detect whether or not a current path is formed.

  Moreover, in this liquid discharge inspection apparatus, a potential detection unit that detects a potential at the electrode unit may be provided as the detection unit. If such a potential detection unit is provided, it is possible to easily check whether or not a current path is formed between the liquid ejection unit and the electrode unit.

  In the liquid discharge inspection apparatus, the potential detected by the potential detection unit may be compared with a predetermined reference potential to determine whether or not the current path has been formed. If such a determination can be made, it can be easily determined whether or not a current path is formed.

  In the liquid discharge inspection apparatus, a voltage may be applied to the electrode portion when performing the discharge inspection. When a voltage is applied to the electrode portion in this way, a current path can be easily formed between the liquid discharge portion and the electrode portion by the liquid discharged from the liquid discharge portion.

  In such a liquid discharge inspection apparatus, the surface of the electrode portion may be subjected to water repellent treatment. Thus, if the surface of the electrode part is subjected to water repellent treatment, the liquid discharged toward the electrode part can be easily removed.

  In addition, such a liquid discharge inspection apparatus may include a cleaning mechanism for removing the liquid from the electrode portion. If such a cleaning mechanism is provided, the liquid can be easily removed from the electrode portion.

  In such a liquid discharge inspection apparatus, the liquid discharged from the liquid discharge unit may be ink. It is possible to easily execute the discharge inspection of the liquid discharge unit that discharges such ink.

In a liquid discharge inspection apparatus for performing a liquid discharge inspection in a liquid discharge unit,
An electrode part provided in a non-contact state with the liquid ejection part;
An operation of discharging the liquid from the liquid discharge portion toward the electrode portion is executed, and a current path is formed by the liquid discharged from the liquid discharge portion between the liquid discharge portion and the electrode portion. It is determined that there is discharge,
When the current path is not formed, it is determined that there is no discharge,
The current path is formed by continuously discharging liquid droplets as the liquid from the liquid discharge portion toward the electrode portion,
A detection unit for detecting whether or not the current path is formed between the liquid ejection unit and the electrode unit;
As the detection unit, provided with a potential detection unit for detecting the potential of the electrode unit,
Comparing the potential detected by the potential detection unit with a predetermined reference potential to determine whether or not the current path is formed;
When performing the ejection inspection, a voltage is applied to the electrode portion,
Water repellent treatment is applied to the surface of the electrode part,
A cleaning mechanism for removing the liquid from the electrode portion;
A liquid discharge inspection apparatus, wherein the liquid discharged from the liquid discharge unit is ink.

A method for performing a liquid discharge inspection in a liquid discharge unit,
An operation of discharging the liquid from the liquid discharge unit toward the electrode unit provided in a non-contact state with the liquid discharge unit,
When a current path is formed between the liquid ejection unit and the electrode unit by the liquid ejected from the liquid ejection unit, it is determined that there is ejection, and when no current path is formed, no ejection is performed. A liquid discharge inspection method characterized by determining.

In a liquid ejection apparatus provided with a liquid ejection unit that ejects liquid to a medium,
Having an electrode portion provided in a non-contact state with the liquid ejection portion;
When the liquid is discharged from the liquid discharge portion toward the electrode portion, and a current path is formed between the liquid discharge portion and the electrode portion by the liquid discharged from the liquid discharge portion, It is determined that there is a discharge,
A liquid discharge apparatus comprising: a liquid discharge inspection unit that determines that there is no discharge when the current path is not formed.

In an ink jet printer including an ink discharge unit that discharges conductive ink to a medium,
An electrode portion provided in a non-contact state with the ink discharge portion;
When the ink is discharged from the ink discharge portion toward the electrode portion, and a current path is formed between the ink discharge portion and the electrode portion by the ink discharged from the ink discharge portion, It is determined that there is a discharge,
An ink jet printer comprising: an ink discharge inspection unit that determines that there is no discharge when the current path is not formed.

A program executed in a liquid discharge inspection apparatus that performs liquid discharge inspection in a liquid discharge unit,
Discharging the liquid from the liquid discharge portion toward the electrode portion provided in a non-contact state with the liquid discharge portion;
When a current path is formed between the liquid ejection unit and the electrode unit by the liquid ejected from the liquid ejection unit, it is determined that ejection is present, and ejection is performed when the current path is not formed. And a step of determining that there is no program.

In a printing system comprising a computer main body and a liquid ejection inspection device connectable to the computer main body,
The liquid discharge inspection apparatus is a liquid discharge inspection apparatus that performs a liquid discharge inspection in a liquid discharge unit,
An electrode part provided in a non-contact state with the liquid ejection part;
When the liquid is discharged from the liquid discharge portion toward the electrode portion, and a current path is formed between the liquid discharge portion and the electrode portion by the liquid discharged from the liquid discharge portion, It is determined that there is a discharge,
A liquid discharge inspection system that determines that there is no discharge when the current path is not formed.

=== Overview of Liquid Discharge Device ===
An embodiment of a liquid ejection apparatus according to the present invention will be described. Here, an ink jet printer will be described as an example of the liquid ejection apparatus according to the present invention.

<Liquid ejection device>
1 to 4 show the ink jet printer 1. FIG. 1 shows the appearance of the inkjet printer 1. FIG. 2 shows the internal configuration of the inkjet printer 1. FIG. 3 shows the transport section of the inkjet printer 1. FIG. 4 is a block diagram showing the system configuration of the inkjet printer 1.

  As shown in FIG. 1, the inkjet printer 1 has a structure for discharging a medium such as printing paper supplied from the back side from the front side, and an operation panel 2 and a paper discharge unit 3 are provided on the front side. The paper feeding unit 4 is provided on the back side. Various operation buttons 5 and display lamps 6 are provided on the operation panel 2. Further, the paper discharge unit 3 is provided with a paper discharge tray 7 that closes the paper discharge port when not in use. The paper feed unit 4 is provided with a paper feed tray 8 that holds cut paper (not shown). Note that the inkjet printer 1 may include a paper feed structure that can print not only on single-sheet-like printing paper such as cut paper but also on continuous media such as roll paper.

  Inside the ink jet printer 1, a carriage 41 is provided as shown in FIG. The carriage 41 is provided so as to be relatively movable along a predetermined direction (in the present embodiment, the scanning direction in the drawing). Around the carriage 41, a carriage motor (hereinafter also referred to as a CR motor) 42, a pulley 44, a timing belt 45, and a guide rail 46 are provided. The carriage motor 42 is constituted by a DC motor or the like, and functions as a drive source for relatively moving the carriage 41 along the predetermined direction. The timing belt 45 is connected to the carriage motor 42 via the pulley 44, and a part of the timing belt 45 is connected to the carriage 41. The carriage 41 is relatively driven along the predetermined direction by the rotation of the carriage motor 42. Move to. The guide rail 46 guides the carriage 41 along the predetermined direction. In addition, around the carriage 41, a linear encoder 51 that detects the position of the carriage 41, a conveyance roller 17 </ b> A for conveying the medium S along a direction that intersects the moving direction of the carriage 41, and this conveyance A paper feed motor 15 that rotationally drives the roller 17A is provided.

  On the other hand, the carriage 41 is provided with an ink cartridge 48 that stores various inks, and a head 21 that performs printing on the medium S. The ink cartridge 48 contains, for example, each color ink such as yellow (Y), magenta (M), cyan (C), black (K), and is detachable from a cartridge mounting portion provided on the carriage 41. It is installed. On the other hand, the head 21 performs printing by ejecting ink onto the medium S in this embodiment. For this purpose, the head 21 is provided with a number of nozzles for ejecting ink. The ink ejection mechanism of the head 21 will be described in detail later.

  In addition, a cleaning unit 30 for eliminating clogging of the nozzles of the head 21 is provided inside the ink jet printer 1. The cleaning unit 30 includes a pump device 31 and a capping device 35. The pump device 31 is a device that sucks out ink from the nozzles in order to eliminate clogging of the nozzles of the head 21, and is operated by a pump motor (not shown). On the other hand, the capping device 35 seals the nozzles of the head 21 when printing is not performed (for example, during standby) in order to prevent clogging of the nozzles of the head 21.

  Next, the configuration of the transport unit of the inkjet printer 1 will be described. As shown in FIG. 3, the transport unit includes a paper insertion port 11A and a roll paper insertion port 11B, a paper feed motor (not shown), a paper feed roller 13, a platen 14, and a paper transport motor (hereinafter referred to as PF). (Also referred to as a motor) 15, a transport roller 17A, a paper discharge roller 17B, a free roller 18A, and a free roller 18B.

  The paper insertion slot 11A is where the paper S, which is a medium, is inserted. The paper feed motor (not shown) is a motor that transports the paper S inserted into the paper insertion slot 11A into the printer 1, and includes a pulse motor or the like. The paper feed roller 13 is a roller that automatically conveys the medium S inserted into the paper insertion slot 11A into the printer 1 in the direction of arrow A in the figure (the direction of arrow B in the case of roll paper). Driven by. The paper feed roller 13 has a substantially D-shaped cross section. Since the circumferential length of the circumferential portion of the feed roller 13 is set to be longer than the transport distance to the PF motor 15, the medium S can be transported to the PF motor 15 using this circumferential portion. The rotational driving force of the paper feed roller 13 and the frictional resistance of the separation pad (not shown) prevent a plurality of media S from being fed at a time.

  The platen 14 is a support unit that supports the paper S during printing. The PF motor 15 is a motor that feeds, for example, paper as the medium S in the paper conveyance direction, and is configured by a DC motor. The transport roller 17 </ b> A is a roller that feeds the paper S transported into the printer 1 by the paper feed roller 13 to a printable area, and is driven by the PF motor 15. The free roller 18A is provided at a position facing the transport roller 17A, and presses the paper S toward the transport roller 17A by sandwiching the paper S with the transport roller 17A.

  The paper discharge roller 17 </ b> B is a roller for discharging the printed paper S to the outside of the printer 1. The paper discharge roller 17B is driven by the PF motor 15 by a gear (not shown). The free roller 18B is provided at a position facing the paper discharge roller 17B, and presses the paper S toward the paper discharge roller 17B by sandwiching the paper S between the paper discharge roller 17B.

<System configuration>
Next, the system configuration of the inkjet printer 1 will be described. As shown in FIG. 4, the inkjet printer 1 includes a buffer memory 122, an image buffer 124, a system controller 126, a main memory 127, and an EEPROM 129. The buffer memory 122 receives and temporarily stores various data such as print data transmitted from the host computer 140. The image buffer 124 acquires the received print data from the buffer memory 122 and stores it. The main memory 127 is composed of a ROM, a RAM, and the like.

  On the other hand, the system controller 126 reads the control program from the main memory 127 and controls the entire printer 1 according to the control program. The system controller 126 of this embodiment includes a carriage motor control unit 128, a conveyance control unit 130, a head drive unit 132, a rotary encoder 134, and a linear encoder 51. The carriage motor control unit 128 drives and controls the rotation direction, rotation speed, torque, and the like of the carriage motor 42. Further, the head drive unit 132 performs drive control of the head 21. The conveyance control unit 130 controls various drive motors arranged in the conveyance system such as the paper conveyance motor 15 that rotationally drives the conveyance roller 17A.

  The print data sent from the host computer 140 is temporarily stored in the buffer memory 122. Necessary information is read from the print data stored here by the system controller 126. Based on the read information, the system controller 126 refers to the output from the linear encoder 51 and the rotary encoder 134 and controls the carriage motor control unit 128, the conveyance control unit 130, and the head drive unit 132 according to the control program. Control each one.

  The image buffer 124 stores print data of a plurality of color components received by the buffer memory 122. The head drive unit 132 acquires print data of each color component from the image buffer 124 according to a control signal from the system controller 126, and drives and controls the nozzles of each color provided in the head 21 based on this print data.

  In addition to these, the inkjet printer 1 according to the present embodiment includes a detection unit 80 and an A / D conversion unit 88. The detection unit 80 and the A / D conversion unit 88 will be described in detail later.

<Head>
FIG. 5 is a diagram showing the arrangement of the ink nozzles provided on the lower surface of the head 21. On the lower surface of the head 21, as shown in the figure, nozzles comprising a plurality of nozzles # 1 to # 180 for each color of yellow (Y), magenta (M), cyan (C), and black (K). A column 211 is provided. The yellow (Y), magenta (M), cyan (C), and black (K) nozzle rows 211 correspond to the liquid ejection unit of the present invention.

  The nozzles # 1 to # 180 of each nozzle row 211 are arranged linearly along the paper S conveyance direction. Each nozzle row 211 is arranged in parallel with a space between each other along the moving direction (scanning direction) of the head 21. Each nozzle # 1 to # 180 is provided with a piezo element (not shown) as a drive element for ejecting ink droplets.

  When a voltage having a predetermined time width is applied between the electrodes provided at both ends of the piezoelectric element, the piezoelectric element expands according to the voltage application time and deforms the side wall of the ink flow path. As a result, the volume of the ink flow path contracts according to the expansion and contraction of the piezo element, and the ink corresponding to the contraction is ejected from the nozzles # 1 to # 180 of each color as ink droplets.

  FIG. 6 shows the drive circuit 220 for each of the nozzles # 1 to # 180. The drive circuit 220 includes an original drive signal generator 221 and a plurality of mask circuits 222 as shown in FIG. The original drive signal generator 221 generates an original signal ODRV that is used in common by the nozzles # 1 to # 180. This original signal ODRV has two pulses, a first pulse W1 and a second pulse W2, within the main scanning period for one pixel (within the time during which the carriage 41 crosses the interval of one pixel), as shown in the lower part of the figure. It is a signal containing. The original signal ODRV generated by the original drive signal generator 221 is output to each mask circuit 222.

  The mask circuit 222 is provided corresponding to a plurality of piezo elements that drive the nozzles # 1 to # 180 of the head 21, respectively. Each mask circuit 222 receives the original signal ODRV from the original signal generator 221 and the print signal PRT (i). The print signal PRT (i) is pixel data corresponding to a pixel, and is a binary signal having 2-bit information for one pixel. Each bit corresponds to the first pulse W1 and the second pulse W2, respectively. The mask circuit 222 is a gate for blocking or passing the original signal ODRV in accordance with the level of the print signal PRT (i). That is, when the print signal PRT (i) is at level “0”, the pulse of the original signal ODRV is cut off, while when the print signal PRT (i) is at level “1”, the corresponding pulse of the original signal ODRV is passed as it is. Then, the drive signal DRV is output toward the piezoelectric elements of the nozzles # 1 to # 180. The piezo elements of the nozzles # 1 to # 180 are driven based on the drive signal DRV from each mask circuit 222 to discharge ink.

  FIG. 7 is a timing chart of the original signal ODRV, the print signal PRT (i), and the drive signal DRV (i) showing the operation of the original drive signal generator 221. As shown in the figure, the original signal ODRV sequentially generates a first pulse W1 and a second pulse W2 in each pixel section T1, T2, T3, T4. The pixel section has the same meaning as the carriage movement section for one pixel.

  Here, when the print signal PRT (i) corresponds to the 2-bit pixel data “10”, only the first pulse W1 is output in the first half of one pixel section. Thereby, a small ink droplet is ejected from the nozzle, and a small dot (small dot) is formed on the medium. When the print signal PRT (i) corresponds to 2-bit pixel data “01”, only the second pulse W2 is output in the second half of one pixel interval. As a result, medium-sized ink droplets are ejected from the nozzles, and medium-sized dots (medium dots) are formed on the medium. When the print signal PRT (i) corresponds to the 2-bit pixel data “11”, the first pulse W1 and the second pulse W2 are output in one pixel section. Thereby, a large size ink droplet is ejected from the nozzle, and a large size dot (large dot) is formed on the medium. As described above, the drive signal DRV (i) in one pixel section is shaped to have three different waveforms according to three different values of the print signal PRT (i), and based on these signals. The head 21 can form dots of three types of sizes and can adjust the amount of ink ejected in the pixel section. When the print signal PRT (i) corresponds to the 2-bit pixel data “00” as in the pixel section T4, no ink droplet is ejected from the nozzle, and no dot is formed on the medium. .

  In the inkjet printer 1 according to the present embodiment, such a drive circuit 220 for the nozzles # 1 to # 180 is provided for each nozzle row 211, that is, yellow (Y), magenta (M), cyan (C), black ( K) is provided separately for each color, and the piezo elements are individually driven for each nozzle # 1 to 180 of each nozzle row 211.

=== Printing operation ===
Next, the printing operation of the above-described ink jet printer 1 will be described. Here, “bidirectional printing” will be described as an example. FIG. 8 is a flowchart showing an example of the processing procedure of the printing operation of the inkjet printer 1. Each process described below is executed by the system controller 126 reading a program stored in the main memory 127 or the EEPROM 129 and controlling each unit according to the program.

  Upon receiving print data from the host computer 140, the system controller 126 first performs a paper feed process to execute printing based on the print data (S102). The paper feed process is a process for supplying a medium to be printed, here, paper into the printer 1 and transporting it to a print start position (also referred to as a cue position). The system controller 126 rotates the paper feed roller 13 to send the paper to be printed to the transport roller 17A. The system controller 126 rotates the transport roller 17A to position the paper fed from the paper feed roller 13 at the print start position.

  Next, the system controller 126 executes a printing process for printing the medium by moving the carriage 41 relative to the medium. Here, first, forward printing is performed in which ink is ejected from the head while the carriage 41 is moved in one direction along the guide rail 46 (S104). The system controller 126 drives the carriage motor 32 to move the carriage 41 and drives the head based on the print data to eject ink. The ink ejected from the head 21 reaches the paper and is formed as dots.

  After printing is performed in this manner, next, a carrying process for carrying the medium by a predetermined amount is executed (S106). In this transport process, the system controller 126 drives the transport motor 15 to rotate the transport roller 17A and transports the paper by a predetermined amount relative to the head 21 in the transport direction. By this carrying process, the head 21 can print in an area different from the previously printed area.

  After carrying out the carrying process in this way, it is determined whether or not to discharge paper (S108). Here, if there is no other data to be printed on the paper being printed, a paper discharge process is executed (S116). On the other hand, if there is other data to be printed on the paper being printed, the return pass printing is executed without performing the paper discharge process (S110). In this backward printing, printing is performed by moving the carriage 41 along the guide rail 46 in the direction opposite to the previous forward printing. Again, the system controller 126 drives the carriage motor 42 to rotate in the opposite direction to move the carriage 41 and drives the head 21 based on the print data to eject ink and perform printing.

  After performing the return pass printing, a carrying process is executed (S112), and then a paper discharge determination is made (S114). Here, if there is other data to be printed on the paper being printed, the process returns to step S104 without performing the paper discharge process, and the forward printing is executed again (S104). On the other hand, if there is no other data to be printed on the paper being printed, a paper discharge process is executed (S116).

  After the paper discharge process is performed, next, a print end determination is performed to determine whether or not to end printing (S118). Here, based on the print data from the host computer 140, it is checked whether there is any paper to be printed next. If there is a sheet to be printed next, the process returns to step S102, the paper feed process is executed again, and printing is started. On the other hand, if there is no paper to be printed next, the printing process ends.

=== Liquid ejection inspection apparatus ===
An embodiment of a liquid discharge inspection apparatus according to the present invention will be described. Here, a case where the liquid discharge inspection apparatus according to the present invention is mounted on an ink jet printer (liquid discharge apparatus) will be described as an example.

<Outline of inspection device>
FIG. 9 schematically illustrates a liquid discharge inspection apparatus 60 mounted on the inkjet printer 1 of the present embodiment and an inspection method thereof. The liquid ejection inspection device 60 includes an electrode plate 70 disposed at a position that can face the head 21, and a detection unit 80 connected to the electrode plate 70. The electrode plate 70 is provided as an electrode portion of the present invention, and is formed of a conductive member such as metal, for example. When the carriage 41 moves, a gap D is provided between the head plate 21 and the electrode plate 70. It is arranged so as to face the head 21 in a non-contact state. The distance D between the head 21 and the electrode plate 70 is set to about 1 mm, for example. A power supply (not shown) for applying a very high voltage such as 100 V (volt) is connected to the electrode plate 70 so that a high voltage is applied. In the present embodiment, the protective resistor R1 is connected in series between the power source and the electrode plate 70.

  On the other hand, the detection unit 80 is connected to detect a potential change in the electrode plate 70. In the present embodiment, the detection unit 80 is configured by a detection circuit including a capacitor C, an input resistor R2, a feedback resistor R3, and an operational amplifier Amp. The capacitor C plays a role of inputting a change in the potential as an electric signal to the operational amplifier Amp through the input resistor R2 when a change in the potential occurs in the electrode plate 70. The operational amplifier Amp serves as an amplifier circuit that amplifies and outputs an electric signal input through the capacitor C. The electrical signal amplified by the operational amplifier Amp is analog / digital converted by an A / D conversion circuit 88 (see FIG. 4) as in the present embodiment, for example, and discharged as a digital data or the like in the system controller 126 or the like. Is transmitted to.

The head 21 is electrically grounded. The ground structure of the head 21 will be described in detail later.
When actually performing an ejection test, an operation of ejecting ink from the nozzles # 1 to # 180 of the head 21 toward the electrode plate 70 is performed. FIG. 10 illustrates how ink is ejected from the nozzle with the head 21 toward the electrode plate 70. Here, the ink droplets Ip are continuously ejected from the nozzles # 1 to # 180 of the head 21. For this reason, since the next ink droplet Ip is ejected from the nozzle before the ink droplet Ip ejected from the nozzle reaches the electrode plate 70, a plurality of inks are interposed between the head 21 and the electrode plate 70. There will be a drop Ip. For example, several to several tens of ink droplets Ip exist between the head 21 and the electrode plate 70.

  At this time, since a high voltage is applied to the electrode plate 70 from the power source, when there are a plurality of ink droplets Ip between the head 21 and the electrode plate 70, the plurality of ink droplets Ip are passed through the plurality of ink droplets Ip. A phenomenon occurs in which current flows from the electrode plate 70 toward the head 21. This is a phenomenon that occurs because the interval between the ink droplets Ip existing between the head 21 and the electrode plate 70 is very short, and between the ink droplets Ip existing between the head 21 and the electrode plate 70. It is considered that a discharge phenomenon occurred in this state, and this caused a state in which a current flows from the electrode plate 70 to the head 21.

  As described above, when the current path Ir is formed between the head 21 and the electrode plate 70, the potential of the electrode plate 70 decreases. This decrease in potential is detected by the detection unit 80 connected to the electrode plate 70. Therefore, it is possible to easily check whether ink is normally ejected from the nozzles # 1 to # 180.

  On the other hand, when the ink is not normally ejected from the nozzles, the ink does not reach the electrode plate 70, so that the current path Ir is not formed between the head 21 and the electrode plate 70. Therefore, no large potential fluctuation occurs on the electrode plate 70 and nothing is detected by the detection unit 80, so that it can be easily determined that the ink is not normally ejected from the nozzles.

  Note that it is preferable that the number of inks ejected from the nozzles # 1 to # 180 at the time of ejection inspection is as large as possible. That is, the size of the ink droplets ejected from the nozzles # 1 to # 180 is preferably as large as possible. This is to make it easier to form the current path Ir between the head 21 and the electrode plate 70. In this case, the size of the ink droplets ejected from the nozzles # 1 to # 180 is preferably set to, for example, a large dot (“11”) in this embodiment. Further, the size of the ink droplet at the time of ejection inspection may be set to be larger than the size of the ink droplet that is normally used at the time of printing.

  Further, it is preferable that the interval between the ink droplets ejected from the nozzles # 1 to # 180 is as short as possible. That is, it is preferable to shorten the cycle of the drive signal for ejecting ink droplets from the nozzles # 1 to # 180 as much as possible. This is to make it easier to form a current path Ir between the head 21 and the electrode plate 70. In this case, the period of the drive signal at the time of ejection inspection may be set shorter than the period at the time of normal printing.

<Electrode plate>
11A and 11B show the appearance of the electrode plate 70 of the present embodiment. FIG. 11A is a plan view of the electrode plate 70, and FIG. 11B is a side view of the electrode plate 70.
As shown in FIG. 11A, the electrode plate 70 of the present embodiment is similarly provided in a rectangular shape on a rectangular substrate 72. The substrate 72 is a printed wiring board, and the electrode plate 70 is formed in a thin layer on the printed wiring board 72 as shown in FIG. 11B. As a method for forming the electrode plate, it is formed by directly attaching to the printed wiring board 72 or by a film forming method such as vapor deposition.
In the present embodiment, circuit elements 82, 83, and 84 that constitute the protection resistor R 1, the capacitor C, the input resistor R 2, the feedback resistor R 3, the operational amplifier Amp, and the like that constitute the detection unit 80 described above are integrally formed on the printed wiring board 72. Has been implemented. Accordingly, the printed wiring board 72 having the electrode plate 70 and the circuit elements 82, 83, and 84 is configured as a unit for performing a discharge inspection of the nozzle row of the head 21.

<Position of electrode plate>
FIG. 12 illustrates the installation position of the electrode plate 70 of the present embodiment. As shown in the figure, the electrode plate 70 of the present embodiment is installed in an area An (hereinafter referred to as a non-printing area) that is out of a printing area Ap where ink is ejected from a nozzle and printing is performed. In this non-printing area An, a pump device 31 that sucks out ink from the nozzles is provided as a cleaning device for the nozzles # 1 to # 180 in order to eliminate clogging of the nozzles. The non-printing area An is provided with a capping device 35 that covers and caps the nozzles # 1 to # 180 of the head 21 when printing is not performed. The pump unit 31 and the capping device 35 constitute a cleaning unit 30. In addition to this, the cleaning unit 30 may be provided with a wiping device or the like that wipes off ink adhering excessively from the openings of the nozzles # 1 to # 180.
The electrode plate 70 of the present embodiment is installed in a position near the printing area Ap in the non-printing area An, that is, between the printing area Ap and the cleaning unit 30 as shown in FIG. Thus, when the carriage 41 moves from the printing area Ap to the non-printing area An, it always passes above the electrode plate 70. Therefore, it is possible to perform the ink ejection inspection at any time during non-printing when the carriage 41 moves to the non-printing area An.

<Positional relationship between electrode plate and nozzle array>
FIG. 13 illustrates the positional relationship between the electrode plate 70 and the nozzle row 211 when the ejection inspection is performed. As shown in the figure, the electrode plate 70 of the present embodiment is formed into a rectangular shape having a vertical dimension L × horizontal dimension M, and the vertical dimension L is set to be longer than the length of the nozzle row 211, and the horizontal dimension thereof. M is set to be larger than the width of the nozzle row 211 and one row. Thus, the electrode plate 70 is formed so as to face the nozzle row 211 for one row.
When performing a discharge inspection, the electrode plate 70 is opposed to one of the plurality of nozzle arrays 211 provided in the head 21 as shown in FIG. Is supposed to do. When the discharge inspection for one nozzle row 211 is completed, the carriage 41 moves so that the next nozzle row 211 that has not yet been subjected to the discharge inspection faces the electrode plate 70. Then, a discharge inspection is performed on the nozzle row 211 facing each other. In this way, the discharge inspection is sequentially performed on the plurality of nozzle rows 211 provided in the head 21.

<Actual detection waveform>
FIG. 14 shows waveforms of a drive signal output for ejecting ink during an ejection test and an output signal from the detection unit 80, respectively. The upper waveform in the figure shows the waveform of the drive signal, and the lower waveform in the figure shows the waveform of the output signal of the detector 80. When performing a discharge inspection for a certain nozzle, it is necessary to continuously discharge ink droplets from that nozzle. Therefore, there are many piezo elements provided in the nozzle to be inspected as shown in FIG. A drive signal having a pulse Wa is output.

  On the other hand, when ink is normally ejected from the nozzle to be inspected by such a drive signal, a current path is formed between the head 21 and the electrode plate 70 by the ink ejected from the nozzle, The potential fluctuation occurs in the electrode plate 70, and this potential fluctuation is detected by the detection unit 80. However, the current path is not formed unless at least the ink ejected from the nozzle to be inspected first reaches the electrode plate 70. As an output waveform of the detection unit 80, as shown in the figure, a mountain-shaped pulse Wb whose rise is delayed compared to the output start timing of the drive signal is obtained.

  On the other hand, when the ink is not normally ejected from the nozzles # 1 to # 180, the ink does not properly reach the electrode plate 70, so that a current path is normally formed between the head 21 and the electrode plate 70. For this reason, the mountain-shaped pulse Wb as shown in the figure does not appear clearly in the output signal of the detector 80.

  The ejection inspection is performed on a plurality of nozzles, for example, one nozzle row 211, that is, 180 nozzles # 1 to # 180. For this reason, as shown in the figure, the drive signal has a form in which a large number of pulses Wa for continuously ejecting the ink droplets Ip are set as one unit, and this is repeatedly output at a predetermined cycle T. On the other hand, the output signal of the detection unit 80 corresponds to this drive signal, and if the ink is normally ejected from the nozzles # 1 to # 180, as shown in FIG. Wb is formed. Here, the predetermined period T is set to 1 k Hertz [Hz], for example. The output waveform of the detection unit 80 is checked individually for each period, and thereby the ejection inspection can be performed individually for each of the nozzles # 1 to # 180.

<Inspection procedure>
Next, the inspection procedure will be described. FIG. A is a flowchart illustrating an example of an inspection procedure in the inkjet printer 1 according to the present embodiment. In the present embodiment, since the size of the electrode plate 70 corresponds to only one nozzle row 211, each nozzle row 211 (K), 211 (C), 211 (M), 211 (Y) Each time the carriage 41 (head 21) is moved, the ejection test is performed individually for each of the nozzle rows 211 (K), 211 (C), 211 (M), and 211 (Y). Here, black (K) nozzle row 211 (K) → cyan (C) nozzle row 211 (C) → magenta (M) nozzle row 211 (M) → yellow (Y) nozzle row 211 (Y) The discharge inspection is performed in the order of.

  First, the cleaning frequency is initialized (S200). This is to set “0” to a counter that counts how many times the cleaning process has been performed during one ejection inspection, that is, how many times there is no ejection. Subsequently, a discharge inspection is performed on the black (K) nozzle row 211 (K) (S202). After the ejection inspection is completed, it is checked whether ink is ejected from the nozzles # 1 to # 180 of the black (K) nozzle row 211 (K) (S204). Here, if there is even one nozzle that does not discharge among the nozzles # 1 to # 180 of the black (K) nozzle row 211 (K), it is checked whether or not the number of cleanings has reached a specified number. (S220). Here, the prescribed number is a number that is considered that the ejection does not recover even if the cleaning process is repeated further. For example, when the number of times is three, when the number of times of cleaning is less than three, the nozzle row cleaning process is performed (S222). Here, the cleaning process is performed by the pump device 31 or the like, and may be performed only on the black (K) nozzle row 211 (K) or may be performed simultaneously with other nozzle rows. After completion of the cleaning process, the number of cleanings is increased by one (S224), and the nozzle row ejection inspection is performed again.

  If it is determined in step S220 that the number of cleanings has reached the specified number, error processing is performed (S226), and the process ends. Here, the error processing may notify the user that there is a nozzle that does not discharge, and prompt the user to take more effective discharge recovery means. Further, replacement of a head including a nozzle that does not discharge may be promoted. Furthermore, nozzles that do not discharge may be stored, and printing may be continued by complementing with other nozzles without using the nozzles.

  On the other hand, if all of the nozzles # 1 to # 180 of the black (K) nozzle row 211 (K) are ejected, the process proceeds to step S206, and the cyan (C) nozzle row 211 (C) is ejected. An inspection is executed (S206). After completion of the ejection inspection, it is checked whether ink is ejected from nozzles # 1 to # 180 of the cyan (C) nozzle row 211 (C) (S208). If even one of the nozzles # 1 to # 180 in the cyan (C) nozzle row 211 (C) does not discharge, the process proceeds to a check of the number of cleanings in step S220.

  On the other hand, if all of the nozzles # 1 to # 180 of the cyan (C) nozzle row 211 (C) are discharged, the process proceeds to step S210, and the magenta (M) nozzle row 211 (M) is discharged. An inspection is executed (S210). After the ejection test is completed, it is checked whether ink is ejected from nozzles # 1 to # 180 of the magenta (M) nozzle row 21 (M) (S212). Here, if any one of the nozzles # 1 to # 180 in the magenta (M) nozzle row 211 (M) does not discharge, the process proceeds to a check of the number of cleanings in step S220.

  If all of the magenta (M) nozzle rows 211 (M) are discharged, the process proceeds to step S214, and a discharge test is performed on the yellow (Y) nozzle row 211 (Y) (S214). . After completion of the ejection test, it is checked whether ink is ejected from the nozzles # 1 to # 180 of the yellow (Y) nozzle row 211 (Y) (S216). Here, if there is any nozzle that does not discharge any of the nozzles # 1 to # 180 in the yellow (Y) nozzle row 211 (Y), the process proceeds to the check of the number of cleanings in step S220.

  On the other hand, when all of the nozzles # 1 to # 180 of the yellow (Y) nozzle row 211 (Y) are ejected, the nozzle rows 211 (K), 211 (C), 211 (M) of all colors, Since there is no ejection for each of the nozzles # 1 to # 180 of 211 (Y), it is determined that “all ejection is present” (S218), and the process ends.

FIG. B is a flowchart when the cleaning process is performed for each nozzle row. First, the number of cleanings is initialized (S240). This is to set “0” to all the counters that count for each nozzle row how many cleaning processes have been performed during one ejection inspection, that is, how many times there has been no ejection. Subsequently, a discharge inspection is performed on the black (K) nozzle row 211 (K) (S242). After the ejection inspection is completed, it is checked whether ink is ejected from the nozzles # 1 to # 180 of the black (K) nozzle row 211 (K) (S244). Here, if even one of the nozzles # 1 to # 180 of the black (K) nozzle row 211 (K) does not discharge, the number of times of cleaning of the black (K) nozzle row 211 (K) is reached. It is checked whether or not the number reaches the specified number (S246). If the number of cleanings is less than the specified number, the black (K) nozzle row 211 (K) is cleaned (S248). After the cleaning process is completed, the number of cleanings of the black (K) nozzle row 211 (K) is increased by one (S250), and the ejection inspection of the black (K) nozzle row 211 (K) is performed again.
If it is determined in step S246 that the number of cleanings has reached the specified number, error processing is performed (S282), and the process ends.

On the other hand, if all of the nozzles # 1 to # 180 of the black (K) nozzle row 211 (K) are ejected, the process proceeds to step S252 to eject the cyan (C) nozzle row 211 (C). An inspection is executed (S252). After completion of the ejection inspection, it is checked whether ink is ejected from nozzles # 1 to # 180 of the cyan (C) nozzle row 211 (C) (S254). Here, if any one of the nozzles # 1 to # 180 of the cyan (C) nozzle row 211 (C) does not discharge, the number of times of cleaning the cyan (C) nozzle row 211 (C) is determined. It is checked whether or not the number reaches the specified number (S256). If the number of cleanings is less than the specified number, the cyan (C) nozzle row 211 (C) is cleaned (S258). After completion of the cleaning process, the number of times of cleaning of the cyan (C) nozzle row 211 (C) is increased by one (S260), and the ejection inspection of the cyan (C) nozzle row 211 (C) is performed again.
If it is determined in step S256 that the number of cleanings has reached the specified number, error processing is performed (S282), and the process ends.

  Hereinafter, for magenta (M) and yellow (Y), the discharge inspection is performed in the same manner, and if there is any nozzle that does not discharge any of nozzles # 1 to # 180, the number of cleanings for that nozzle row is A check is made as to whether or not the specified number has been reached. If the number of cleanings is less than the specified number, a cleaning process is performed, the number of cleanings for the nozzle row is increased by one, and a discharge inspection is performed again. If the number of cleanings has reached the specified number, error processing is performed (S282) and the process ends.

  If all of the nozzles # 1 to # 180 of the yellow (Y) nozzle row 211 (Y) are ejected in step S274, the nozzle rows 211 (K), 211 (C), 211 (M) of all colors are ejected. ) And 211 (Y), since there is no ejection for each of the nozzles # 1 to # 180, it is determined that “all ejection is present” (S284), and the process is terminated.

  FIG. 16 is a flowchart for explaining the procedure of ejection inspection for each nozzle row 211 (K), 211 (C), 211 (M), and 211 (Y). First, the head 21 is moved toward the electrode plate 70 (S302). Then, alignment is performed so that the nozzle row 211 to be inspected and the electrode plate 70 face each other (S304). Next, an initial value “1” is set to the variable “N” (S306), and an operation of continuously ejecting ink droplets from the “N” -th nozzle (nozzle #N) toward the electrode plate 70 is executed. Then, a discharge inspection is performed (S308). After the end of ejection, a value of “N + 1” is set to the variable “N” (S310), and it is checked whether or not the variable “N” exceeds “180” that is the number of nozzles (S312). Here, when the variable “N” exceeds “180”, it is determined that the discharge inspection has been completed for all the nozzles, and the process is terminated.

  On the other hand, if the variable “N” does not exceed “180”, it is determined that all the nozzles # 1 to # 180 have not been inspected, and the process returns to step S308, and then the “N + 1” -th nozzle ( An ink ejection operation is performed for nozzle # N + 1) to perform ejection inspection (S308). Thereafter, the value of “N + 1” is set again to the variable “N” (S310), and each of the nozzles # 1 to # 180 is sequentially and individually set until the variable “N” exceeds “180” which is the number of nozzles. A discharge inspection is performed.

  In this embodiment, the series of inspection processes is executed by the system controller 126 based on a program read from the main memory 127 or the EEPROM 129, or is executed based on a command from the host computer 140. .

<Inspection timing>
The timing at which the discharge inspection is performed includes the following.

(1) During printing process Ejection inspection is executed at an appropriate timing during the printing process. For example, in the case of “bidirectional printing”, when the moving direction is changed, the carriage 41 moves to the non-printing area An, and the ejection inspection of the nozzles # 1 to # 180 is executed. As a result, it is possible to avoid the occurrence of defects in the printed image due to clogging of the nozzles # 1 to # 180 during the printing process.

(2) When the power is turned on When the power is turned on, the discharge inspection is executed. In this case, in order to perform printing from now on, a discharge inspection is executed when the printer 1 (printing apparatus) is powered on. As one of the processes during the initialization process of the printer 1, the discharge inspection of the nozzles # 1 to # 180 is performed. Execute. By performing the ejection inspection with such a timing, the printing process can be smoothly executed without clogging of the nozzles # 1 to # 180.

(3) At the time of paper feed A discharge inspection is executed at the time of an operation for feeding a medium to a predetermined position for printing, that is, at the time of paper feed. This is to check whether or not the ink is normally ejected when printing is performed on one medium from now on, and each time the medium S is fed, the ejection inspection may be performed. In addition, the discharge inspection may be executed for each predetermined number at an appropriate interval.

(4) When acquiring print data When the printer receives print data from a host computer 140 such as a personal computer, the ejection inspection is executed. That is, when printing data is received from the host computer 140 and printing is to be executed, it is checked whether or not ink is normally ejected. By executing the ejection inspection at such timing, the printing process can be smoothly executed without clogging of the nozzles # 1 to # 180.

  Note that the ejection inspection in the present invention is not necessarily performed at the timings (1) to (4) described above, and the ejection inspection is performed at a timing other than (1) to (4). Also good.

<Summary>
As described above, according to such a liquid discharge inspection apparatus, it is checked whether or not a current path is formed between the head 21 and the electrode plate 70 by the ink discharged from the nozzles # 1 to # 180 of the head 21. Since the presence or absence of ejection is determined, the ejection inspection can be performed very easily. Therefore, the apparatus configuration is very compact, does not require a very large installation space, and does not incur a significant cost increase.
In addition, since such a liquid discharge inspection apparatus is mounted on a liquid discharge apparatus such as an ink jet printer as described above, it is possible to perform a discharge inspection very easily, and without causing much trouble in discharging defects. It can be solved easily.

=== Ground structure of the head ===
The head 21 described above may be electrically grounded. FIG. 17 is a diagram for explaining an example of the ground structure of the head 21, and shows an example of the internal structure of the head 21. As shown in the figure, the head 21 shown here includes a piezoelectric vibrator group 154 including a plurality of piezoelectric vibrators 152, a vibrator unit 150 in which a fixed plate 156, a flexible cable 158, and the like are unitized, A case 160 that can accommodate the vibrator unit 150 and a flow path unit 170 that is joined to the front end surface of the case 160 are provided.

  The piezoelectric vibrator 152 is the piezo element described above, and the piezoelectric vibrator 152 is configured by alternately laminating the piezoelectric bodies 151 and the internal electrodes 153, and has an elongated comb tooth shape along the vertical direction. . The piezoelectric vibrator 152 expands and contracts along the longitudinal direction, that is, the longitudinal direction, by an external drive signal. The front end (lower end) of the piezoelectric vibrator 152 is joined to the flow path unit 170 via the island 172.

  The flow path unit 170 includes an elastic plate 174, a flow path forming substrate 176, and a nozzle plate 178. The nozzle plate 178 is a thin plate made of stainless steel, for example, and has a number of nozzle openings 180 formed at a predetermined pitch. Nozzles # 1 to # 180 are formed by the nozzle openings. A pressure chamber 182 is formed for each nozzle opening 180 in the flow path forming substrate 176.

  When the piezoelectric vibrator 152 is expanded or contracted, the elastic plate 174 is bent upward or downward, and the pressure chamber 182 contracts or expands. As a result, ink is supplied from the ink supply chamber 184 through the ink supply path 186 to the pressure chamber 182. Further, the ink accumulated in the pressure chamber 182 is ejected from the nozzle opening 180 as ink droplets.

  When grounding the head 21 having such an ink discharge mechanism, a ground wire 190 is connected to the nozzle plate 178 of the flow path unit 170 described above, and the ground wire 190 is connected to an appropriate metal member, for example, a guide race. If 46 is made of metal, it is connected to a guide rail 48 or the like. If the nozzle plate 178 is grounded through the ground wire 190 in this way, the head 21 can be easily grounded.

<Electrode plate cleaning mechanism>
Next, a cleaning mechanism for the electrode plate 70 will be described. In the ejection inspection, the ink ejected from each nozzle may reach the electrode plate and adhere to the electrode plate as it is, depending on its properties and materials. If ink adheres to the electrode plate, there is a possibility that the discharge inspection may be adversely affected.

  Therefore, it is preferable to provide a cleaning mechanism for removing ink from the electrode plate. 18, 19A, and 19B illustrate an embodiment of the electrode plate cleaning mechanism 200 of the present invention. FIG. 18 is a perspective view illustrating an outline of the cleaning mechanism 200, FIG. 19A illustrates a state before cleaning, and FIG. 19B illustrates a state after cleaning.

  As shown in FIG. 18, the cleaning mechanism 200 includes a wiping member 202 and a holding member 204 that holds the wiping member 202. The wiping member 202 is a member formed of an elastic material such as rubber. As shown in the figure, the upper end of the wiping member 202 is held by the holding member 204 and the lower end of the wiping member 202 contacts the surface of the electrode plate 70. In contact with the surface of the electrode plate 70, the ink is wiped off from the surface and removed.

  On the other hand, the holding member 204 is connected to a drive mechanism (not shown) that slides the holding member 204 back and forth along the surface of the electrode plate 70. The holding member 204 slides back and forth along the surface of the electrode plate 70 while holding the wiping member 202 as shown in FIG.

  FIGS. 19A and 19B illustrate the cleaning procedure by the cleaning mechanism 200. FIG. As shown in FIG. 19A, the holding member 204 stands by on the base 72b side (the left end side in the figure) of the substrate 72 on which the electrode plate 70 is provided, while the discharge inspection is being performed. When a discharge inspection is performed and a certain amount of ink is deposited on the electrode plate 70, the holding member 204 moves from the standby position along with the wiping member 202 along the surface of the electrode plate 70 in the direction of arrow F in the figure. Slide along. The wiping member 202 slides along the surface of the electrode plate 70 while the tip end (lower end) thereof is in close contact with the surface of the electrode plate 70, and is deposited on the electrode plate 70 as shown in FIG. 19B. The ink G is wiped away.

  A recovery member 206 that recovers the ink removed from the electrode plate 70 is provided below the front end portion 72a side (the right end side in the figure) of the substrate 72 on which the electrode plate 70 is provided. The ink G removed from the electrode plate 70 falls from the electrode plate 70 and is collected by the collection unit 207 of the collection member 206.

As described above, by providing such a cleaning mechanism, it is possible to remove the ink deposited on the electrode plate 70 by the discharge inspection, and it is possible to prevent the ink from adhering to the electrode plate 70 to cause a problem.
The surface of the electrode plate 70 is preferably subjected to a water repellent treatment so that the ink can be easily removed.

  FIG. 20 is a perspective view showing another embodiment of the cleaning mechanism. The cleaning mechanism 210 includes a wiping member 212 and a holding member 214 that holds the wiping member 212, and the wiping member 212 is attached to the surface of the electrode plate 70 by the driving force of an external driving mechanism connected to the holding member 214. The ink is slid along the surface while being in close contact with the ink, and the ink is wiped off from the surface of the electrode plate.

=== Other Embodiments of Electrode Portion ===
FIG. 21A, FIG. 21B, and FIG. 21C show other embodiments of the electrode part of the present invention, respectively. FIG. 21A shows an embodiment when an electrode plate 70 having a narrow lateral width is provided as the electrode portion of the present invention. FIG. 21B shows an embodiment when an electrode plate 70 having a wide width is provided as the electrode portion of the present invention. These electrode plates 70 in FIGS. 21A and 21B are both provided on a substrate 72. As shown in FIG. 21A, if the electrode plate 70 is formed narrow, further downsizing can be achieved. Further, as shown in FIG. 21B, if the lateral width of the electrode plate 70 is formed wider, a discharge inspection can be performed for a plurality of nozzle rows 211 collectively. Thereby, the efficiency of inspection processing and the reduction of inspection time can be achieved.

  FIG. 21C shows an embodiment when an electrode wire 74 is provided as the electrode portion of the present invention. The electrode wire 74 is formed of a wire made of a conductive material such as metal, for example, like the electrode plate. As shown in the figure, the electrode wire 74 of the present embodiment is stretched along the longitudinal direction of the substrate 72, that is, the longitudinal direction, at the center of the opening 76 formed at the tip of the substrate 72. Both end portions of the electrode wire 74 are fixed to the inner edge portion of the opening 76.

  As described above, the electrode portion is constituted by the electrode line 74 and is stretched over the opening 76 formed in the substrate 72, so that the ink ejected from the nozzles # 1 to # 210 of the head 21 at the time of ejection inspection is the electrode line. Even when the ink reaches 74, the ink can be naturally dropped from the electrode line 74, so that the ink can be easily removed from the electrode line 74 without using the above-described cleaning mechanisms 200 and 210. be able to.

  In addition, it is preferable that the surface of the electrode portions such as the electrode plate 70 and the electrode wire 74 is subjected to a water repellent treatment. This is to make it easy to remove the ink droplets ejected from the nozzle from the electrode plate 70 and the electrode line 74 when they reach the electrode plate 70 and the electrode line 72. By performing water-repellent treatment on the surfaces of the electrode plate 70 and the electrode wire 72, for example, even when the ink is removed by the cleaning mechanisms 200 and 210 described above, the operation can be easily performed.

  The water repellent treatment includes a known method including a method of providing a water repellent treatment layer or the like on the surface of the electrode portion such as the electrode plate 70 or the electrode wire 74 by coating or the like.

=== Configuration of Liquid Discharge System etc. ===
Next, as an example of the liquid discharge system according to the present invention, a liquid discharge system including an ink jet printer as a liquid discharge device will be described as an example.

  FIG. 22 is an explanatory diagram showing an external configuration of the liquid ejection system. The liquid ejection system 1000 includes a computer main body 1102, a display device 1104, a printer 1106, an input device 1108, and a reading device 1110. In this embodiment, the computer main body 1102 is housed in a mini-tower type housing, but is not limited thereto. The display device 1104 is generally a CRT (Cathode Ray Tube), a plasma display, a liquid crystal display device, or the like, but is not limited thereto. As the printer 1106, the printer described above is used. In this embodiment, the input device 1108 is a keyboard 1108A and a mouse 1108B, but is not limited thereto. In this embodiment, the reading device 1110 uses a flexible disk drive device 1110A and a CD-ROM drive device 1110B. However, the reading device 1110 is not limited to this. Disk) etc. may be used.

  FIG. 23 is a block diagram showing a configuration of the liquid ejection system shown in FIG. An internal memory 1202 such as a RAM and an external memory such as a hard disk drive unit 1204 are further provided in a housing in which the computer main body 1102 is housed.

  The computer program for controlling the operation of the printer 1 can be downloaded to a computer 1000 or the like connected to the printer 1106 via a communication line such as the Internet, and recorded on a computer-readable recording medium. It can also be distributed. As the recording medium, for example, various recording media such as a flexible disk FD, a CD-ROM, a DVD-ROM, a magneto-optical disk MO, a hard disk, and a memory can be used. Note that information stored in such a storage medium can be read by various reading devices 1110.

  In the above description, an example in which the printer 1106 is connected to the computer main body 1102, the display device 1104, the input device 1108, and the reading device 1110 to configure the liquid ejection system has been described. However, the present invention is not limited to this. is not. For example, the liquid ejection system may include a computer main body 1102 and a printer 1106, and the liquid ejection system may not include any of the display device 1104, the input device 1108, and the reading device 1110. Further, for example, the printer 1106 may have a part of each function or mechanism of the computer main body 1102, the display device 1104, the input device 1108, and the reading device 1110. As an example, the printer 1106 includes an image processing unit that performs image processing, a display unit that performs various displays, a recording medium attachment / detachment unit for attaching / detaching a recording medium that records image data captured by a digital camera or the like. It is good also as a structure to have.

  The printing system realized in this way is a system superior to the conventional system as a whole system.

=== Other Embodiments ===
As described above, the printing apparatus such as an ink jet printer has been described based on one embodiment. However, the above embodiment is for facilitating understanding of the present invention, and is intended to limit the interpretation of the present invention. It is not a thing. The present invention can be changed or improved without departing from the gist thereof, and needless to say, the present invention includes equivalents thereof. In particular, even the embodiments described below are included in the liquid discharge inspection apparatus, the liquid discharge apparatus, and the liquid discharge system according to the present invention.

  In the present embodiment, part or all of the configuration realized by hardware may be replaced by software, and conversely, part of the configuration realized by software may be replaced by hardware.

  Further, a part of the processing performed on the liquid ejection apparatus (inkjet printer 1) side may be performed on the host computer 140 side, and a dedicated process is performed between the liquid ejection apparatus (inkjet printer 1) and the host computer 140. A part of the processing may be performed by this processing apparatus via an apparatus.

<About liquid>
In the above-described embodiment, the case where ink is used as the liquid has been described as an example. However, the liquid ejection apparatus according to the present invention is not limited to ink, but other liquids such as metal materials, organic Various liquids such as materials (for example, polymer materials), magnetic materials, conductive materials, wiring materials, film forming materials, electronic ink, various processing liquids, and gene solutions may be used instead of ink.

<About the liquid ejection unit>
In the above-described embodiment, the nozzle row 211 of the head 21 of the ink jet printer 1 has been described as the liquid discharge portion of the present invention. However, in the liquid discharge portion of the present invention, such a nozzle row 211 is used. The present invention is not limited to this, and any type of discharge unit may be used as long as it discharges liquid.

<About the electrode section>
In the embodiment described above, the electrode plate 70 and the electrode wire 74 have been described as the electrode portion of the present invention. However, the electrode portion of the present invention is not limited to such an electrode plate 70 and the electrode wire 74. Instead, other shapes and other types of electrode portions may be used.

  In the above-described embodiment, the electrode plate 70 and the electrode wire 74 provided on the substrate 72 are described as the electrode portion of the present invention. However, in the electrode portion of the present invention, this is not necessarily the case. It is not necessary to be provided on the correct substrate 72, and it may be installed in another form.

  In the embodiment described above, the head 21 is the ground side and a high voltage is applied to the electrode portion (electrode plate 70). However, the present invention is not limited to such a case, and the electrode portion ( A current path that flows from the head 21 to the electrode portion when a high voltage is applied to the head 21 side and liquid (ink) is discharged from the liquid discharge portion (nozzle array) with the electrode plate 70) as the ground side. You may make it form.

<About current path>
In the above-described embodiment, the current path is formed by the plurality of ink droplets existing between the head 21 and the electrode plate 70. However, the current path of the present invention is not limited to such a case. Any form of current path may be used as long as it is formed by the liquid discharged from the liquid discharge section.

<About the detector>
In the above-described embodiment, the detection unit 80 that detects the potential fluctuation of the electrode unit (electrode plate 70) has been described as the detection unit of the present invention. However, in the detection unit of the present invention, As long as it is possible to detect whether or not a current path is formed between the liquid ejection unit (nozzle row 211 of the head 21) and the electrode unit (electrode plate 70), the detection unit 80 is not limited. Such a type of detection unit may be used. For example, a detection unit that detects the current flowing through the electrode unit and checks whether or not a current path is formed may be used.

<Discharge inspection>
In the above-described embodiment, the ejection inspection is performed for each nozzle. In the ejection inspection according to the present invention, ink is ejected simultaneously from a plurality of nozzles, and the ejection inspection is performed on two or more nozzles simultaneously. You may make it do. In this case, for example, from the difference between the potential fluctuation amount of the electrode portion when the ink is normally ejected from two or more nozzles and the potential fluctuation amount of the electrode portion when the ejection failure nozzle is included, The presence or absence of discharge can be individually examined for each nozzle.

<About liquid ejection inspection device>
In the above-described embodiment, the liquid discharge inspection apparatus mounted on the liquid discharge apparatus using the ink jet printer as an example has been described as the liquid discharge inspection apparatus. However, in the liquid discharge inspection apparatus according to the present invention, It is not limited to such a device, and may be a device that can be separated from the liquid ejection device and can independently perform only the liquid ejection inspection, and is mounted on other devices other than the liquid ejection device described above. A liquid discharge inspection apparatus may be used.

<About liquid ejection device>
In the above-described embodiment, the ink jet printer has been described as an example of the liquid discharge inspection apparatus. However, the liquid discharge apparatus according to the present invention is not limited to such an ink jet printer, and is an apparatus that discharges liquid. Any device may be used as long as it is present.

<About the cleaning mechanism>
In the above-described embodiment, the cleaning mechanisms 200 and 210 including the wiping members 202 and 212 and the holding members 204 and 214 have been described as the cleaning mechanism of the present invention. Not only such a mechanism but also other types of cleaning mechanisms may be used as long as the liquid is removed from the electrode portion.

<About media>
As for the media, the above-mentioned paper includes plain paper, matte paper, cut paper, glossy paper, roll paper, paper, photographic paper, roll type photographic paper, etc. In addition to these, films such as OHP film and glossy film It may be a material, a cloth material, a metal plate material, or the like. That is, any medium can be used as long as it can be an ink ejection target.

  DESCRIPTION OF SYMBOLS 1 Inkjet printer, 2 Operation panel, 3 Paper discharge part, 4 Paper feed part, 5 Operation button, 6 Display lamp, 7 Paper discharge tray, 8 Paper feed tray, 11A Paper insertion slot, 11B Roll paper insertion slot, 13 Paper feed Roller, 14 Platen, 15 Paper transport motor (PF motor), 17A Transport roller, 17B Discharge roller, 18A / 18B Free roller, 21 head, 211 Nozzle row, 22 Head driver, 30 Cleaning unit, 31 Pump device, 35 Capping Device, 41 Carriage, 42 Carriage motor (CR motor), 44 Pulley, 45 Timing belt, 46 Guide rail, 48 Ink cartridge, 51 Linear encoder, 60 Discharge inspection device, 70 Electrode plate, 72 Substrate, 74 Electrode wire, 80 Detector, 88 A / D change Conversion unit, 122 buffer memory, 124 image buffer, 126 system controller, 127 main memory, 128 carriage motor control unit, 129 EEPROM, 130 transport control unit, 132 head drive unit, 134 rotary encoder, 136 linear encoder, 140 host Computer, 150 vibrator unit, 151 piezoelectric body, 152 piezoelectric vibrator, 153 internal electrode, 154 piezoelectric vibrator group, 156 fixed plate, 158 flexible cable, 160 case, 170 channel unit, 172 island, 174 elastic plate, 176 Flow path forming substrate, 178 nozzle plate, 180 nozzle opening, 182 pressure chamber, 184 ink supply chamber, 186 ink supply path, 190 ground wire, 200 cleaning mechanism, 202 W Member, 204 holding member, 206 collecting member, 207 collecting unit, 210 cleaning mechanism, 212 wiping member, 214 holding member, 211 nozzle row, 220 driving circuit, 221 original driving signal generating unit, 222 mask circuit, 1200 display device, 1201 display, 1300 input device, 1300A keyboard, 1300B mouse, 1400 recording / playback device, 1400A flexible disk drive device, 1400B CD-ROM drive device, 1000 liquid ejection system, Ap printing area, An non-printing area, S medium, Ip ink Drop, R1 protection resistance, R2 input resistance, R3 feedback resistance, C capacitor, Amp operational amplifier.

Claims (6)

A liquid discharge section for discharging liquid;
An electrode portion provided in a non-contact state with the liquid discharge portion;
A potential detection unit for detecting the potential of the electrode unit,
A liquid discharge inspection apparatus that performs an operation of discharging the liquid from the liquid discharge portion toward the electrode portion, detects a change in the potential of the electrode portion, and performs a discharge inspection in the liquid discharge portion. ,
The liquid ejection inspection apparatus , wherein a period of a drive signal for ejecting the liquid when performing the ejection inspection is shorter than a period of a drive signal for ejecting the liquid when performing printing . A liquid discharge section for discharging liquid;
An electrode portion provided in a non-contact state with the liquid discharge portion;
A potential detection unit for detecting the potential of the electrode unit,
A liquid discharge inspection apparatus that performs an operation of discharging the liquid from the liquid discharge portion toward the electrode portion, detects a change in the potential of the electrode portion, and performs a discharge inspection in the liquid discharge portion. ,
The liquid discharge inspection apparatus, wherein an interval for discharging the liquid when performing the discharge inspection is shorter than an interval for discharging the liquid when performing printing.   The liquid ejection inspection apparatus according to claim 1, wherein the ejection inspection is performed when a medium is fed. The liquid ejection unit includes a first nozzle and a second nozzle,
The liquid discharge inspection apparatus according to any one of claims 1 to 3, wherein the discharge inspection at the first nozzle and the discharge inspection at the second nozzle are performed simultaneously. A liquid discharge section for discharging liquid; and an electrode section provided in a non-contact state with the liquid discharge section;
A liquid discharge inspection method using an apparatus including a potential detection unit that detects a potential of the electrode unit,
Performing an operation of discharging the liquid from the liquid discharge unit toward the electrode unit;
Detecting a change in the potential at the electrode section;
Perform a discharge inspection in the liquid discharge unit,
A liquid ejection inspection method , wherein a period of a drive signal for ejecting the liquid when performing the ejection inspection is shorter than a period of a drive signal for ejecting the liquid when performing printing . A liquid discharge section for discharging liquid; and an electrode section provided in a non-contact state with the liquid discharge section;
A liquid discharge inspection method using an apparatus including a potential detection unit that detects a potential of the electrode unit,
Performing an operation of discharging the liquid from the liquid discharge unit toward the electrode unit;
Detecting a change in the potential at the electrode section;
Perform a discharge inspection in the liquid discharge unit,
A liquid discharge inspection method, wherein an interval of discharging the liquid when performing the discharge inspection is shorter than an interval of discharging the liquid when performing printing.

Images