JP2010188625A - Liquid delivery device and method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain inspection precision from getting worse caused by a difference between distances from respective nozzle lines up to an inspection area, and to prevent total time required for inspection from getting long. <P>SOLUTION: In a printer, a carriage motor and a printing head 24 are controlled to deliver ink from the inspection-objective nozzle line 68 set sequentially, while moving the printing head 24 along a main scanning direction, under the condition where a voltage is impressed between the printing head 24 and the inspection area 521, and each nozzle 23 is inspected based on an electric change between the printing head 24 and the inspection area 521, at the time when the printing head 24 is controlled to deliver the ink from the inspection-objective nozzle 23 set sequentially. The ink is delivered from the inspection-objective nozzle 23 set sequentially, in every prescribed timing, while moving the printing head 24 at a velocity v in which the ink delivered from each nozzle 23 does not exceed a width W of the inspection area 521 when finishing the inspection for all the nozzles 23. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fluid ejection device and a method thereof.

  Conventionally, inkjet printers that detect voltage changes caused by ejecting charged ink droplets from the nozzles of the print head to the ink receiving area and inspect whether the ink is ejected normally from the nozzles have been proposed Has been. In such an ink jet printer, a plurality of nozzle rows are formed in a print head, and the plurality of nozzle rows are sequentially set as inspection target nozzle rows, and a plurality of nozzles constituting the set inspection target nozzle rows are sequentially set as inspection target nozzles. The nozzle inspection is executed for the set inspection target nozzle. Specifically, as shown in FIG. 9, an inspection area equal to or wider than the entire nozzle row width is provided, and printing is performed in a state where the print head is arranged so that all the nozzle rows face the inspection area. Nozzle inspection is performed for the inspection target nozzles that are sequentially set with the head fixed. In this case, a value nt obtained by multiplying the time t required for nozzle inspection for one nozzle row to be inspected by the number n of nozzle rows is the total time T required for nozzle inspection (T = nt). However, if the inspection area is tilted or has minute irregularities, there will be a short nozzle line or a long nozzle line to the inspection area. There has been a problem that the voltage generated when ink is ejected fluctuates, which may affect the inspection accuracy.

  In consideration of this point, for example, in Patent Document 1, as shown in FIG. 10, the inspection area is set to one nozzle row, and the print head is fixed in a state where the first nozzle row and the inspection region face each other. After performing the inspection of the nozzle row, the intermittent operation of moving the print head until the next nozzle row faces the inspection area, fixing the print head in that state, and executing the inspection of the nozzle row is repeated. It has been proposed. In this case, since the distance to the inspection region is constant regardless of the nozzle row, the above problem does not occur.

JP 2007-38566 A

  However, in the case of the nozzle inspection shown in FIG. 10, the total time T required for the inspection is the movement time τ (1) obtained by multiplying the time t required for the nozzle inspection for one inspection target nozzle row by the value nt multiplied by the number n of nozzle rows. (The value obtained by multiplying the number of times of movement by the number of times of movement)) (T = nt + τ). In addition, noise may occur between the print head and the inspection area after the print head is stopped, and it is necessary to add a waiting time to the total time T in order to avoid the influence of the noise. For this reason, although the inspection accuracy is improved as compared with the case where the width of the inspection region is wide, there arises a problem that the total time T required for the inspection becomes long.

  The present invention has been made in view of the above-described problems, and suppresses a decrease in inspection accuracy due to a difference in distance from each nozzle row to an inspection region and prevents an increase in the total time required for the inspection. Main purpose.

  In order to achieve the above-mentioned main object, the fluid ejection device and method of the present invention employ the following means.

The fluid ejection device of the present invention is
Three or more nozzle rows are formed and a discharge head that discharges fluid from nozzles constituting each nozzle row;
Head moving means for moving the ejection head in a main scanning direction substantially orthogonal to the nozzle row;
An inspection region that is formed narrower than the entire nozzle row width and receives fluid discharged from the nozzles constituting the nozzle row of the discharge head;
An inspection target setting unit that sequentially sets a plurality of nozzles constituting the inspection target nozzle row as inspection target nozzles while setting the inspection target nozzle row in order from an end of the plurality of nozzle rows;
The ejection head moves so that fluid is ejected from the nozzles to be inspected that are sequentially set while moving the ejection head in the main scanning direction with a voltage applied between the ejection head and the inspection area. Means for controlling each of the nozzles based on an electrical change between the ejection head and the inspection area, and for controlling the ejection head moving means. Control means for controlling the ejection head moving means so that the fluid ejected from each nozzle when the examination is completed does not exceed the width of the examination area, and the ejection head moves in the main scanning direction;
It is equipped with.

  In this fluid ejection device, while a voltage is applied between the ejection head and the inspection region, ejection is performed so that fluid is ejected from the inspection target nozzles that are sequentially set while moving the ejection head in the main scanning direction. The head moving means and the ejection head are controlled, and each nozzle is inspected based on the electrical change between the ejection head and the inspection area at that time. When controlling the ejection head moving means, the ejection head moves in the main scanning direction at a speed at which the fluid ejected from each nozzle does not exceed the width of the inspection area when the inspection of all nozzles is completed. Controls the head moving means. For this reason, compared with the case where fluid is ejected from the nozzles to be inspected sequentially at predetermined timings while the ejection head is fixed in a state where the ejection head is opposed to the inspection area having the same width as the entire nozzle row width, Since the area is narrowed, it is possible to suppress a decrease in inspection accuracy due to a difference in distance from each nozzle row to the inspection area. Further, since the total time required for the inspection is equivalent to that case, it can be shortened compared with the case where the nozzle inspection is performed with an intermittent operation.

  In the fluid ejection device of the present invention, the speed may be determined such that sequentially set inspection target nozzle rows are periodically located at the same position in the inspection region. In this way, the width of the inspection region can be reduced even if the number of nozzle rows is large.

  In the fluid ejection device of the present invention, the control means controls the ejection head so that the fluid is ejected from the first nozzle of the initially set nozzle array to be inspected, and then sets the last nozzle array to be inspected. The ejection head moving unit may be controlled so that the ejection head moves in the main scanning direction at a constant speed until the ejection head is controlled so that fluid is ejected from the last nozzle. By doing so, it is possible to avoid the influence of noise generated during acceleration / deceleration compared to the case where the nozzle inspection is performed not only when the ejection head is at a constant speed but also during acceleration and deceleration.

  In the fluid ejection device of the present invention, the intervals between the nozzle rows are equally spaced p [mm], the number of nozzle rows formed in the ejection head is n [rows] (where n is an integer of 3 or more), Assuming that the distance that the ejection head moves from the start to the end of inspection of nozzles for one inspection target nozzle row is d [mm], d <2p (n−1) / n is satisfied. Also good. . By doing so, the fluid discharged from each nozzle when the inspection of all nozzles is completed does not exceed the width of the inspection region. The velocity v of the ejection head at this time is a value obtained by dividing the distance d [mm] by the time t required from the start to the end of the nozzle inspection for one inspection target nozzle row. In particular, if the distance d is d = p, the width of the inspection region can be minimized.

  In the fluid ejection device of the present invention, all nozzle rows are arranged in groups of two nozzle rows arranged adjacent to each other with a spacing p [mm], and each group is arranged with a spacing q [mm], and is formed on the ejection head. The number of the nozzle rows is n [rows] (where n is an even number of 4 or more), and the distance that the ejection head moves from the start to the end of the nozzle inspection for one inspection target nozzle row When d is [mm], d <p + q− (2q / n) may be satisfied. By doing so, the fluid discharged from each nozzle when the inspection of all nozzles is completed does not exceed the width of the inspection region. The moving speed of the ejection head at this time is a value obtained by dividing the distance d [mm] by the time t required from the start to the end of the nozzle inspection for one inspection target nozzle row. In particular, if d = (p + q) / 2, the width of the inspection region can be minimized.

The control method of the fluid ejection device of the present invention includes:
Three or more nozzle rows are formed, a discharge head that discharges fluid from the nozzles constituting each nozzle row, head moving means that moves the discharge head in the main scanning direction substantially orthogonal to the nozzle rows, and the total nozzle row width An inspection region that receives fluid discharged from nozzles that are formed narrower than the nozzle array of the discharge head, and a control method for the fluid discharge device,
(A) a step of sequentially setting a plurality of nozzles constituting the inspection target nozzle row as inspection target nozzles while sequentially setting the inspection target nozzle row from an end of the plurality of nozzle rows;
(B) In a state in which a voltage is applied between the ejection head and the inspection area, the fluid is ejected at predetermined timings from the inspection target nozzles sequentially set while moving the ejection head in the main scanning direction. The step of controlling the ejection head moving means and the ejection head and inspecting each nozzle based on the electrical change between the ejection head and the inspection area, in controlling the ejection head moving means, Controlling the ejection head moving means so that the ejection head moves in the main scanning direction at a speed at which the fluid ejected from each nozzle does not exceed the width of the inspection area when all nozzles have been inspected; ,
Is included.

  In this fluid ejection device control method, when all nozzles have been inspected, the inspection target is sequentially set while the ejection head is moved at a speed that does not exceed the width of the inspection area. The fluid is discharged from the nozzle at every predetermined timing. For this reason, compared with the case where fluid is ejected from the nozzles to be inspected sequentially at predetermined timings while the ejection head is fixed in a state where the ejection head is opposed to the inspection area having the same width as the entire nozzle row width, Since the area is narrowed, it is possible to suppress a decrease in inspection accuracy due to a difference in distance from each nozzle row to the inspection area. Further, since the total time required for the inspection is equivalent to that case, it can be shortened compared with the case where the nozzle inspection is performed with an intermittent operation.

1 is a configuration diagram illustrating an example of a schematic configuration of a printer 20 according to an embodiment. FIG. 3 is a block diagram showing electrical connection of a print head 24. FIG. 2 is a block diagram showing an outline of the configuration of a nozzle inspection device 50. The flowchart of a nozzle test routine. FIG. 4 is an explanatory diagram illustrating a relationship between an inspection area 521 during execution of nozzle inspection and the print head 24. Explanatory drawing which shows the movement condition of the nozzle row 68 at the time of a nozzle test | inspection. FIG. 6 is an explanatory diagram of nozzle rows 681 to 688 formed on the print head 24. Explanatory drawing which shows the movement condition of the nozzle row 681-688 at the time of a nozzle test | inspection. It is explanatory drawing of the conventional nozzle test | inspection. It is explanatory drawing of the conventional nozzle test | inspection.

  Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram illustrating an example of a schematic configuration of the printer 20 according to the present embodiment, FIG. 2 is a block diagram illustrating electrical connection of the print head 24, and FIG. 3 is a nozzle inspection device 50. It is a block diagram which shows the outline of a structure.

  As shown in FIG. 1, the printer 20 according to the present embodiment includes a printing mechanism 21 including a printing head 24 that ejects ink as a fluid onto a recording paper P as a target, and a head driving substrate mounted on a carriage 22. 62, a paper feed mechanism 30 that conveys the recording paper P, a capping device 40 that performs sealing and cleaning of the print head 24, and a nozzle that performs nozzle inspection to determine whether ink is being ejected from the print head 24 An inspection apparatus 50 and a controller 70 that controls the entire printer 20 are provided.

  The printing mechanism 21 includes a carriage 22 that reciprocates left and right (main scanning direction) along a carriage shaft 28 by a carriage belt 32, and a print head 24 that applies pressure to each color ink and ejects ink droplets as fluid from nozzles 23. And an ink cartridge 26 that stores ink of each color and supplies the stored ink to the print head 24. As the carriage 22 is driven by the carriage motor 34a, the carriage belt 32 laid between the carriage motor 34a attached to the right side of the mechanical frame 39 and the driven roller 34b attached to the left side of the mechanical frame 39 is driven. Move. A linear encoder 25 that detects the position of the carriage 22 is disposed on the rear surface of the carriage 22, and the position of the carriage 22 can be managed using the linear encoder 25. The carriage 22 has a head driving substrate 62 for driving the print head 24. The print head 24 is provided below the carriage 22 and ejects ink of each color from the nozzles 23 provided on the lower surface of the print head 24 by pressurizing the ink. The print head 24 is connected to the ground. On the lower surface of the print head 24, as shown in FIG. 2, a nozzle array in which a plurality of nozzles 23 for ejecting ink of each color of cyan (C), magenta (M), yellow (Y), and black (K) are arranged. 68 is provided. In this embodiment, each nozzle row 68 is formed at intervals of p [mm]. Therefore, the total nozzle row width L is L = 3p (see FIG. 2). Here, all nozzles are collectively referred to as nozzles 23, all nozzle rows are collectively referred to as nozzle rows 68, cyan nozzles and nozzle rows are nozzles 23C and 68C, magenta nozzles and nozzle rows are nozzles 23M and nozzle rows. The 68M, yellow nozzle and nozzle row are referred to as nozzle 23Y and nozzle row 68Y, and the black nozzle and nozzle row are referred to as nozzle 23K and nozzle row 68K. Hereinafter, description will be given using the nozzle 23K. In the print head 24, 180 nozzles 23K are arranged along the conveyance direction of the recording paper P to form a nozzle row 68K. Each nozzle 23K is provided with a piezoelectric element 66 as a drive element for ejecting ink droplets. By applying a voltage to the piezoelectric element 66, the piezoelectric element 66 is deformed to pressurize the ink and press the nozzle 23K. Discharge. The ink cartridge 26 is mounted on the carriage 22 and is used for printing of cyan (C), magenta (M), yellow (Y), black (K), etc. containing pigment or dye as a colorant in water as a solvent. Each color ink to be used is individually accommodated.

  As shown in FIG. 2, the head driving substrate 62 has a mask circuit 64 for applying a voltage to the piezoelectric element 66. The head driving substrate 62 is connected to a flat cable 63 (see FIG. 1) via a connector portion (not shown), and exchanges signals with the controller 70 via the flat cable 63. The mask circuit 64 is provided corresponding to the piezoelectric element 66 that drives each nozzle 23K. The mask circuit 64 receives the original signal ODRV and the print signal PRTn generated by the head drive waveform generation circuit 60 on the control board (not shown). The original signal ODRV is composed of a first pulse P1, a second pulse P2, and a third pulse P3 that are included in an interval of one pixel (within a time during which the carriage 22 crosses the interval of one pixel). The original signal ODRV having these three pulses P1 to P3 as a repeating unit is referred to as one pixel section in this embodiment. The print signal PRTn is a signal generated based on the presence / absence of dots formed on the recording paper P and the size thereof. Note that n at the end of the print signal PRTn is a number for specifying the nozzles included in the nozzle row. In this embodiment, since the nozzle row is composed of 180 nozzles, n is any number from 1 to 180. It becomes a numerical value. When the original signal ODRV and the print signal PRTn are input, the mask circuit 64 outputs necessary pulses among the first pulse P1, the second pulse P2, and the third pulse P3 based on these signals as the drive signal DRVn (n Is the same as n of the print signal PRTn) and is output toward the piezoelectric element 66 of the nozzle 23K. Specifically, when only the first pulse P1 is output from the mask circuit 64 to the piezoelectric element 66, one shot of ink droplet is ejected from the nozzle 23K, and a small size dot (small dot) is formed on the recording paper P. It is formed. When the first pulse P1 and the second pulse P2 are output to the piezoelectric element 66, two shots of ink droplets are ejected from the nozzle 23K, and medium-sized dots (medium dots) are formed on the recording paper P. The Further, when the first pulse P1, the second pulse P2, and the third pulse P3 are output to the piezoelectric element 66, three shots of ink droplets are ejected from the nozzle 23K, and a large size dot (large size) is formed on the recording paper P. Dot) is formed. As described above, the printer 20 can form three types of dots by adjusting the amount of ink ejected in one pixel section. The other color nozzles 23C, 23M, and 23Y and the nozzle rows 68C, 68M, and 68Y are the same as the nozzle 23K and the nozzle row 68K.

  As shown in FIG. 1, the paper feed mechanism 30 is mounted on a paper feed roller 35 that is driven by a drive motor 33 and transports the recording paper P from the back to the front in the drawing or a tray (not shown). A paper feed roller that feeds the recording paper P to the platen 29, a paper discharge roller that transports the recording paper P discharged from the platen 29 to a paper discharge tray (not shown), and the like.

  As shown in FIG. 3, the capping device 40 includes a cap 42 formed of an insulating member having an approximately rectangular parallelepiped shape and an upper opening, and is disposed at an initial position (home position) of the carriage 22. . A sealing member 41 made of an insulator such as silicon rubber is provided at the opening edge of the capping device 40. The capping device 40 is supported by an elevating device 47 so as to be movable up and down. Although not shown, the cap 42 is provided with a suction pump and an air release valve. The suction pump is used when forcibly sucking out ink from the nozzles 23 by setting the inside of the cap 42 to a negative pressure while the cap 42 is lifted and brought into close contact with the print head 24 by the lifting device 47 during cleaning. The air release valve is used to return the inside of the cap 42 to the atmospheric pressure after the cleaning is completed. The cap 42 is used not only for inspecting the presence or absence of nozzle clogging, but also for sealing the nozzle 23 to prevent the nozzle 23 from drying during a printing pause or the like.

  As shown in FIG. 3, the nozzle inspection device 50 includes an ink receiving area 52 that can receive ink droplets discharged from the nozzles 23 of the print head 24, and a print head by setting the ink receiving area 52 to a predetermined potential. 24 and a voltage application circuit 53 that generates a predetermined potential difference between the ink receiving area 52 and a voltage detection circuit 54 that detects a voltage change in the ink receiving area 52.

  The ink receiving area 52 is provided inside the cap 42 that seals the print head 24. The ink receiving area 52 includes an ink absorbing member 43 and an electrode member 44 disposed on the upper surface of the ink absorbing member 43. The ink absorbing member 43 is formed of a highly permeable sponge, nonwoven fabric, or the like that allows the landed ink droplets to quickly move downward. The electrode member 44 is a mesh-like thin plate made of stainless steel (SUS). The electrode member 44 serves to prevent the ink absorbing member 43 from absorbing ink and expanding upward, and at the time of nozzle inspection, the print head 24. It also plays a role as a counter electrode opposite to. Since the electrode member 44 is formed in a mesh shape, the ink discharged from the print head 24 is allowed to move to the ink absorbing member 43. When the electrode member 44 is arranged on the upper surface of the ink absorbing member 43, the heads of the three support rods 42a integrally formed on the bottom surface of the cap 42 are inserted into the round holes provided at the cross points of the mesh, It is caulked by heating and pressurizing its head. The electrode member 44 is electrically connected to an electrode pin 45 that penetrates the bottom surface of the cap 42 in an airtight and liquidtight state. In the present embodiment, the width W of the inspection area 521 used for the nozzle inspection in the ink receiving area 52 is set smaller than the entire nozzle row width L. Further, as shown in FIG. 5, the left end of the inspection region 521 is referred to as an inspection start position S, and the right end is referred to as an inspection end position E.

  As shown in FIG. 3, the voltage application circuit 53 is connected to the electrode member 44 in the ink receiving area 52, and the voltage of the electrical wiring of several volts drawn inside the printer 20 is passed through a booster circuit (not shown). In this circuit, the voltage is boosted to several tens to several hundred volts, and the boosted DC voltage Ve (for example, 400 V) is applied to the ink receiving area 52 including the inspection area 521 through the resistance element R1 (for example, 1 MΩ) and the switch SW. is there.

  The voltage detection circuit 54 is connected to the electrode member 44 in the ink receiving area 52 and detects a voltage change in the inspection area 521 caused by ink ejection. The voltage detection circuit 54 integrates and outputs the voltage signal of the print head 24. The integration circuit 54a, the inverting amplification circuit 54b that receives and inverts and outputs the signal output from the integration circuit 54a, and the signal that is output from the inverting amplification circuit 54b are input and A / D converted. And an A / D conversion circuit 54c for outputting to the controller 70. The integration circuit 54a outputs a large voltage change by integrating the voltage change due to the flight of a plurality of ink droplets ejected from the same nozzle 23 because the voltage change due to the flight of one ink droplet is weak. is there. The inverting amplifier circuit 54b inverts the sign of the voltage change and amplifies and outputs the signal output from the integrating circuit 54a at a predetermined amplification factor determined by the circuit configuration. The A / D conversion circuit 54 c converts the analog signal output from the inverting amplification circuit 54 b into a digital signal and outputs it to the controller 70. The voltage application circuit 53 and the voltage detection circuit 54 are mounted on a substrate in a circuit case 51 that is separate from the cap 42.

  The controller 70 is mounted on a control board (not shown) attached to the mechanical frame 39, and is configured as a microprocessor centered on the CPU 72 as shown in FIG. 1, and can store various processing programs and rewrite data. A flash ROM 73, a RAM 74 for temporarily storing data and storing data, and an interface (I / F) 75 for exchanging data with an external device such as a user personal computer (PC) 110 are provided. The flash ROM 73 stores processing programs such as a nozzle inspection routine and a cleaning processing routine. The RAM 74 is provided with a print buffer area in which a print job sent from an external device such as a user personal computer (PC) 110 via the I / F 75 is stored. In addition to a detection signal output from the voltage detection circuit 54 of the nozzle inspection device 50 being input to the controller 70 via an input port (not shown), a print job output from an external device (such as the user personal computer 110). Etc. are input via the I / F 75. Further, from the controller 70, a control signal to the mask circuit 64 mounted on the print head 24, a control signal to the nozzle inspection device 50, a drive signal to the drive motor 33, the carriage motor 34a, and the lifting device 47 are not shown. Output via the output port.

  Next, the operation of the printer 20 of this embodiment configured as described above, particularly the operation for inspecting clogging of the nozzles 23 will be described. FIG. 4 is a flowchart showing an example of a nozzle inspection routine executed by the CPU 72 of the controller 70. This routine is executed when nozzle inspection is instructed. The timing for executing the nozzle inspection may be the timing at the end of printing one page, the end of printing a predetermined number of pages, the predetermined pass, or the like when the power is turned on or a print job is received. FIG. 5 is an explanatory diagram showing the positional relationship between the inspection area 521 during the nozzle inspection execution and the print head 24, and the numbers in the circles and squares indicate the nozzle numbers.

  When the nozzle inspection routine is started, the CPU 72 of the controller 70 first sets an inspection target nozzle row and an inspection target nozzle (step S100). The inspection target nozzle row is set in the order of yellow (Y) nozzle row 68Y, magenta (M) nozzle row 68M, cyan (C) nozzle row 68C, and black (K) nozzle row 68K. This setting order is for the case where the carriage 22 is positioned on the left side of the cap 42 in FIG. 1 before the execution of the nozzle inspection routine. Further, the inspection target nozzles are set in the order from the first nozzle 23 to the 180th nozzle in one nozzle row 68.

  Next, the switch SW of the voltage application circuit 53 is turned on (step S110). As a result, a voltage (400 V) is applied between the print head 24 and the inspection area 521. Subsequently, the carriage motor 34a is driven to move the carriage 22 across the space above the cap 42 at a speed v (step S120). In this embodiment, the width W of the inspection region 521 is 5 mm, which is the same as the interval p between the nozzle rows, and the time t required for the inspection of one nozzle is 5 msec. In this case, the time Z required for the inspection of all the nozzles included in one nozzle row is 5 msec × 180 nozzles = 0.9 sec. In other words, it can be said that the inspection of each nozzle is started at every predetermined timing, that is, every 5 msec required for the inspection of one nozzle. The speed v of the carriage 22 during the nozzle inspection is set to a value p / t obtained by dividing the interval p between the nozzle rows by the time t, that is, 5 mm / 0.9 sec = 5.6 mm / sec. For this reason, the distance d that the print head 24 moves from the start to the end of the inspection of all nozzles included in one nozzle row is a value vZ obtained by multiplying the speed v by the time Z, that is, 5.6 mm / sec. * Since 0.9 sec = 5 mm, which is equal to the interval p between the nozzle rows, when the current inspection target nozzle row reaches the inspection end position E, the next inspection target nozzle row must reach the inspection start position S. become.

  Subsequently, it is determined whether or not the first inspection target nozzle row, that is, the yellow (Y) nozzle row 68Y faces the inspection start position S of the inspection region 521 (step S130). If the first inspection target nozzle row still does not face the inspection start position S, the process returns to step S130 again. On the other hand, if the first inspection target nozzle row faces the inspection start position S, the mask circuit of the print head 24 is configured so that ink is ejected from the inspection target nozzle, that is, the first nozzle 23Y of the yellow (Y) nozzle row 68Y. 64 and the piezoelectric element 66 are controlled (step S140), and it is determined whether or not the level (amplitude) of the output signal waveform between the print head 24 and the inspection region 521 at that time is equal to or higher than the threshold value Vthr (step S150). . Here, the principle of nozzle inspection will be described. An experiment in which ink droplets are ejected from the nozzles 23 in a state where a potential difference is generated between the print head 24 and the inspection region 521 is actually performed by grounding the print head 24. The output signal waveform appeared as a sine curve. The principle that such an output signal waveform can be obtained is considered to be that an induced current flows due to electrostatic induction as a charged ink droplet is ejected to the inspection region 521. Further, the amplitude of the output signal waveform output from the voltage detection circuit 54 tends to increase as the distance from the print head 24 to the inspection area 521 decreases, and also increases as the flying ink droplet increases. It was. For this reason, when the nozzle 23 is clogged and the ink droplet does not fly or the ink droplet is smaller than a predetermined size, the amplitude of the output signal waveform is smaller than that at the normal time or becomes almost zero, so the output signal waveform Whether or not the nozzle 23 is clogged can be determined based on whether or not the amplitude is less than a predetermined threshold value Vthr. Here, even if the ink droplet has a predetermined size, since the amplitude of the output signal waveform by the ink droplet for one shot is weak, a large number of ink droplets (e.g., the operation of ejecting a large dot is performed eight times) In addition to discharging, the signal is amplified by the inverting amplifier circuit 54b. Therefore, the output signal can be an integrated value of a large number of ink droplets, and a sufficiently large output signal waveform can be obtained from the voltage detection circuit 54. The number of ink ejections can be arbitrarily set so as to be the number of ejections that can ensure inspection accuracy. The threshold value Vthr can be set empirically so that the ejection of ink droplets can be determined.

  When the output level is less than the threshold value Vthr in step S150, it is considered that an abnormality such as clogging has occurred in the nozzle to be inspected this time, and information for identifying the nozzle (for example, information indicating which nozzle in which nozzle row is located) ) Is stored in a predetermined area of the RAM 74 (step S160). After step S160 or when the output level is equal to or higher than the threshold value Vthr in step S150 (that is, when the current nozzle to be inspected is normal), the CPU 72 has inspected all the nozzles included in the current nozzle row to be inspected. If there is a nozzle that has not been inspected yet, the nozzle to be inspected is updated to an uninspected nozzle (step S180), and then the processing from step S140 is performed again. On the other hand, when all the nozzles 23 included in the current inspection target nozzle row are inspected in step S170, it is determined whether or not all the nozzle rows 68 included in the print head 24 have been inspected (step S190). If the uninspected nozzle row 68 remains, the inspection target nozzle row is updated to the uninspected nozzle row 68 and the inspection target nozzle is set to the first nozzle in the updated inspection target nozzle row (step S200), and thereafter, the processes after step S140 are performed again. On the other hand, when all the nozzle arrays 68 included in the print head 24 have been inspected in step S190, the carriage motor 22a stops rotating to stop the moving carriage 22 (step S210). The switch SW is turned off (step S220), and this nozzle inspection routine is terminated.

  By executing this routine, if there is a nozzle 23 in which an abnormality has occurred among all the nozzles 23 arranged in the print head 24, information for specifying the nozzle 23 is stored in the predetermined area of the RAM 74. If there is no nozzle 23 in which an abnormality has occurred, nothing is stored. In addition, as shown in FIG. 5, the print head 24 moves at a speed from the time when the yellow (Y) nozzle 68Y reaches the inspection start position S to the time when the black (K) nozzle 68K reaches the inspection end position E. While moving at a constant speed with v (= p / t), an operation of ejecting ink at predetermined timings from the sequentially set nozzles to be inspected is executed. Since the distance d that the print head 24 moves during the time Z required for the inspection of all nozzles included in one nozzle row is the same as the interval p, when the current inspection target nozzle row reaches the inspection end position E, The next inspection target nozzle row reaches the inspection start position S. As a result, the ink ejected from each nozzle 23 does not exceed the width W (= d = p) of the inspection region 521.

  Here, the correspondence between the components of the present embodiment and the components of the present invention will be clarified. The printer 20 of this embodiment corresponds to the fluid discharge device of the present invention, the print head 24 corresponds to the discharge head, the carriage motor 22a corresponds to the head moving means, the inspection area 521 corresponds to the inspection area, and the controller 70. The CPU 72 corresponds to inspection object setting means and control means. In the present embodiment, an example of the control method of the fluid ejection device of the present invention is also clarified by describing the operation of the printer 20.

  According to the present embodiment described above, the ink ejected from each nozzle 23 when the inspection of all nozzles 23 is completed at a moving speed v (= p / t) that does not exceed the width W of the inspection region 521. While moving the print head 24, ink is ejected from the sequentially set inspection target nozzles at a predetermined timing (time required for inspection of one nozzle is 5 msec). For this reason, as shown in FIG. 9, ink is ejected from the sequentially set inspection target nozzles at the same timing as described above, with the print head being fixed to the inspection area having the same width as the entire nozzle row width L while being fixed. Compared to the case, the width W of the inspection region 521 can be narrowed, and accordingly, a decrease in accuracy due to a difference in distance from each nozzle row 68 to the inspection region 521 can be suppressed. In particular, since the moving speed v is the value p / t, that is, the distance d is equal to the interval p, the width W of the inspection region 521 can be set to the minimum value p. Further, the total time Z required for the inspection can be set to 5 msec × 180 nozzles × 4 nozzle rows = 3.6 sec as in the case of FIG. 9, and the nozzle inspection is performed with an intermittent operation as shown in FIG. Can be shortened.

  Further, the speed v of the print head 24 during execution of the nozzle inspection routine is that the next inspection target nozzle row is located at the inspection start position S when the current inspection subject nozzle row comes to the inspection end position E. Even if the number of nozzle rows is large, the width W of the inspection region 521 can be reduced.

  Further, since the nozzle inspection is performed while the print head 24 is moving at a constant speed v, the nozzle inspection is performed not only during the constant speed but also during acceleration and deceleration. In comparison, noise during acceleration / deceleration can be avoided.

  It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be implemented in various modes as long as it belongs to the technical scope of the present invention.

For example, in the above-described embodiment, when setting the moving speed v (= d / t), the distance d by which the print head 24 moves from the start to the end of the nozzle inspection for one nozzle row is set as the nozzle. Although the width W of the inspection region 521 is minimized by making it equal to the distance p between the columns, the distance d is not necessarily equal to the distance p. That is, the relationship between the position of each nozzle row 68, the distance d, and the interval p during the nozzle inspection is as shown in FIG. Here, when the number of nozzle rows formed in the print head 24 is n, the width W of the inspection region 521 and the total nozzle row width L are expressed by the following formulas (1) and (2). From these formulas (1) and (2), in order to make the width W of the inspection region 521 smaller than the entire nozzle row width L (that is, W <L is satisfied), the condition of formula (3) should be satisfied. Is self-evident in mathematics. Therefore, the effect of the present invention can be obtained by setting the distance d so as to satisfy the condition of the expression (3). It is clear from the equation (1) that the width W is minimized when the distance d is d = p.
W = d + (n-1) | dp |… (1)
L = p (n-1)… (2)
d <2p (n-1) / n (n is an integer greater than or equal to 3) ... (3)

In the above-described embodiment, the intervals between the nozzle rows are all equal intervals p. However, as shown in FIG. 7, all the nozzle rows 681 to 688 are arranged adjacent to each other at intervals of p [mm] For example, when the nozzle row 681 and the nozzle row 682) are one group and the groups are arranged at equal intervals q [mm], the distance d may be set based on FIG. FIG. 8 is an explanatory diagram showing the relationship between the positions of the nozzle rows 681 to 688, the distance d, and the interval p during the nozzle inspection. Here, if the number of nozzle rows formed in the print head 24 is n (where n is an even number of 4 or more), the width W of the inspection region 521 and the total nozzle row width L are expressed by the following equations (4), ( 4) It is represented by 'and (5). From these equations, it is mathematically obvious that the condition of equation (6) should be satisfied in order to make the width W of the inspection region 521 smaller than the entire nozzle row width L (that is, W <L is satisfied). Therefore, the effect of the present invention can be obtained by setting the distance d so as to satisfy the condition of Expression (6). Note that it is clear from the equation (4) that the width W is minimized when the length d satisfies d = (p + q) / 2 (d should be determined so that the coefficient of n is zero).
When d <p <q, W = d + (n / 2) (pd) + [(n / 2) -1] (qd) (4)
When p <d <q, p <q <d W = d + (n / 2) (dp) + [(n / 2) -1] (dq)… (4) '
L = (n / 2) p + [(n / 2) -1] q (5)
d <p + q- (2 / n) q (n is an even number greater than or equal to 4)… (6)

  In the embodiment described above, the electrode member 44 of the ink receiving region 52 is disposed on the upper surface of the ink absorbing member 43, but it may be disposed so as to be sandwiched between the middle stages of the ink absorbing member 43. In this case, the ink absorbing member 43 may be conductive, but the ink absorbing member 43 may be non-conductive because the ink is water-soluble and conductive.

  In the above-described embodiment, the print head 24 is connected to the ground, and a voltage is applied to the electrode member 44 to generate a potential difference between the print head 24 and the inspection region 521. However, the electrode member 44 is connected to the ground. And a potential difference may be generated between the print head 24 and the inspection area 521 by applying a voltage to the print head 24. Further, the potential of the electrode on the side connected to the ground is not limited to the ground but may be a potential that is different from the voltage of the voltage application circuit 53 and gives a predetermined potential difference with the voltage of the voltage application circuit 53. Good. Note that the electrode that applies a predetermined potential in the print head 24 may be any electrode that can conduct the ink in the print head 24 and apply a potential to the ink, such as a nozzle plate or an electrode in the head.

  In the above-described embodiment, both the circuits 53 and 54 are connected to the inspection region 52. However, both the circuits 53 and 54 are both connected to the print head 24, or one of the both circuits 53 and 54 is connected to the electrode member 44 and the print head. The other of the circuits 53 and 54 may be connected to the other of the electrode member 44 and the print head 24.

  In the above-described embodiment, the inspection area 521 is provided inside the capping device 40. However, the inspection area 521 is not particularly limited thereto. For example, the inspection area 521 is periodically provided to prevent the ink from drying and thickening. Alternatively, it may be provided in a flushing region in which ink droplets are ejected at a predetermined timing regardless of print data, or may be newly provided in a region where the print head 24 is movable.

  In the above-described embodiment, the print head 24 applies a voltage to the piezoelectric element 66 and deforms the piezoelectric element 66 to pressurize the ink. However, the ink is applied to the heating resistor (for example, a heater) by applying a voltage. A method may be employed in which the ink is pressurized with bubbles generated by heating. The ink cartridge 26 is configured as a so-called on-carriage mounted on the carriage 22 that reciprocates, but may be configured as a so-called off-carriage that is mounted on the mechanical frame 39 and supplies ink or the like to the print head 24 through a tube.

  In the embodiment described above, an example in which the printer 20 that ejects ink onto the recording paper P is embodied has been described. However, whether or not fluid is ejected from the nozzle by providing a potential difference between the print head 24 and the inspection region 521. The present invention can be applied without particular limitation as long as it can be detected. For example, it may be a printing device that discharges a liquid (dispersion) in which particles of liquid other than ink or functional material are dispersed, a fluid such as a gel, or a solid that can be discharged as a fluid. The present invention may be embodied in a printing apparatus that discharges. For example, a liquid discharge device that discharges a liquid in which a material such as an electrode material or a color material used for manufacturing a liquid crystal display, an EL (electroluminescence) display, a surface emitting display, and a color filter is dissolved, or a liquid material in which the material is dispersed It is good also as a liquid discharge apparatus which discharges the liquid used as a liquid material discharge apparatus which discharges, and a sample used as a precision pipette. Also, a liquid ejection device that ejects a transparent resin liquid such as an ultraviolet curable resin on a substrate to form a micro hemispherical lens (optical lens) used for an optical communication element or the like, a fluid ejection device that ejects a gel, A powder discharge type recording apparatus that discharges powder such as toner may be used.

  In the embodiment described above, the printer 20 has been described as the fluid ejection device of the present invention. However, a multifunction printer including a scanner unit capable of reading a document or a FAX device having a FAX function may be used.

  20 Printer, 21 Printing mechanism, 22 Carriage, 23, 23C, 23M, 23Y, 23K Nozzle, 24 Print head, 25 Linear encoder, 26 Ink cartridge, 28 Carriage shaft, 29 Platen, 30 Paper feed mechanism, 32 Carriage belt, 33 drive motor, 34a carriage motor, 34b driven roller, 35 paper feed roller, 39 mechanical frame, 40 capping device, 41 sealing member, 42 cap, 42a support rod, 43 ink absorbing member, 44 electrode member, 45 electrode pin, 47 Lifting device, 50 nozzle inspection device, 51 circuit case, 52 ink receiving area, 53 voltage application circuit, 54 voltage detection circuit, 54a integration circuit, 54b reverse amplification circuit, 54c A / D conversion circuit, 60 head drive Waveform generation circuit, 62 head drive substrate, 63 flat cable, 64 mask circuit, 66 piezoelectric element, 68, 68C, 68M, 68Y, 68K nozzle array, 70 controller, 72 CPU, 73 flash ROM, 74 RAM, 75 interface, 110 User PC, 521 Inspection area, 681-688 Nozzle array, P recording paper, R1 resistance element, SW switch.

Claims (8)

Three or more nozzle rows are formed and a discharge head that discharges fluid from nozzles constituting each nozzle row;
Head moving means for moving the ejection head in a main scanning direction substantially orthogonal to the nozzle row;
An inspection region that is formed narrower than the entire nozzle row width and receives fluid discharged from the nozzles constituting the nozzle row of the discharge head;
An inspection target setting means for sequentially setting a plurality of nozzles constituting the inspection target nozzle row as inspection target nozzles and setting the inspection target nozzle row in order from an end of the plurality of nozzle rows;
The ejection head moves so that fluid is ejected from the nozzles to be inspected that are sequentially set while moving the ejection head in the main scanning direction with a voltage applied between the ejection head and the inspection area. Means for controlling each of the nozzles based on an electrical change between the ejection head and the inspection area, and for controlling the ejection head moving means. Control means for controlling the ejection head moving means so that the fluid ejected from each nozzle when the examination is completed does not exceed the width of the examination area, and the ejection head moves in the main scanning direction;
A fluid ejection device comprising: The speed is determined so that the sequentially set nozzle rows to be inspected periodically come to the same position in the inspection area.
The fluid ejection device according to claim 1. The control means controls the ejection head so that the fluid is ejected from the first nozzle of the initially set inspection target nozzle row, and then the fluid is discharged from the last nozzle of the last set inspection target nozzle row. Until the ejection head is controlled, the ejection head moving means is controlled so that the ejection head moves in the main scanning direction at a constant speed.
The fluid ejection device according to claim 1 or 2. The intervals between the nozzle rows are equally spaced p [mm], the number of nozzle rows formed in the ejection head is n [rows] (where n is an integer of 3 or more), and the number of nozzle rows corresponding to the inspection target nozzle row. When the distance that the ejection head moves from the start to the end of the nozzle inspection is d [mm],
d <2p (n-1) / n
Meet,
The fluid ejection device according to claim 1. d = p,
The fluid ejection device according to claim 4. All nozzle rows are arranged in groups of two nozzle rows that are arranged adjacent to each other at an interval p [mm], and each group is arranged at an interval q [mm]. The number of nozzle rows formed in the ejection head N [rows] (where n is an even number equal to or greater than 4), and d [mm] represents the distance that the ejection head moves from the start to the end of the inspection of nozzles for one inspection target nozzle row When
d <p + q- (2q / n)
Meet,
The fluid ejection device according to claim 1. d = (p + q) / 2,
The fluid ejection device according to claim 6. Three or more nozzle rows are formed, a discharge head that discharges fluid from the nozzles constituting each nozzle row, head moving means that moves the discharge head in the main scanning direction substantially orthogonal to the nozzle rows, and the total nozzle row width An inspection region that receives fluid discharged from nozzles that are formed narrower than the nozzle array of the discharge head, and a control method for the fluid discharge device,
(A) a step of sequentially setting a plurality of nozzles constituting the inspection target nozzle row as inspection target nozzles while sequentially setting the inspection target nozzle row from an end of the plurality of nozzle rows;
(B) In a state in which a voltage is applied between the ejection head and the inspection area, the fluid is ejected at predetermined timings from the inspection target nozzles sequentially set while moving the ejection head in the main scanning direction. The step of controlling the ejection head moving means and the ejection head and inspecting each nozzle based on the electrical change between the ejection head and the inspection area, in controlling the ejection head moving means, Controlling the ejection head moving means so that the ejection head moves in the main scanning direction at a speed at which the fluid ejected from each nozzle does not exceed the width of the inspection area when all nozzles have been inspected; ,
Control method for fluid ejection device including

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