JP2007098571A - Print head inspection equipment, printer, print head inspection method and it's program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quickly get a grip on dislocation in the arrangement of nozzles of a print head. <P>SOLUTION: The inkjet printer 20 has print head inspection equipment 50 which detects induced voltage caused by the arrival of charged ink droplets at an ink receiving area 52. The ink receiving area 52 is divided into a first area 52a and a second area 52b, interposed by the transfer side edge 63 of an inspection plate 60 as a border line. The equipment detects induced voltage occurring in the ink receiving area 52 at the time when charged ink droplets are sequentially discharged from the first area 52a to the second area 52b from nozzles 23 forming a nozzle array 43 designed so as to line up in parallel with the border line on the print head 24 and get a grip on whether or not ink droplets arrive at areas where they are designed to practically arrive on the basis of detected induced voltage. The equipment performs the same operation for the nozzles 23 forming lines of nozzles. Thus, the equipment gets a grip on the dislocation of the nozzles 23 by directly detecting ink droplets. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a print head inspection apparatus, a printing apparatus, a print head inspection method, and a program thereof.

Conventionally, as a print head inspection apparatus, ink droplets are ejected from a nozzle provided on a print head of an ink jet printer onto an inspection sheet such as resin or paper, and the ink droplets ejected on the inspection sheet are photographed by a camera. In addition, there is known a technique in which a gap between adjacent ink droplets is calculated by processing a photographed image, and nozzle displacement is detected by comparing the calculated value with a normal value (for example, Patent Document 1). reference).
JP 2005-14216 A

  However, in the print head inspection apparatus described in Patent Document 1, after the ink is ejected by the printer and printed on the inspection sheet, the printed inspection sheet is moved to the inspection table of the print head inspection apparatus, and the inspection is performed. There is a problem that it is necessary to take an image from a camera while scanning the inspection sheet on the table, and to process the captured image.

  The present invention has been made in view of such problems, and provides a print head inspection apparatus, a printing apparatus, a print head inspection method, and a program thereof that can more quickly grasp the displacement of the nozzles of the print head. The purpose is to do.

  The present invention adopts the following means in order to achieve the above-mentioned object.

That is, the print head inspection apparatus of the present invention is
A print head inspection apparatus for inspecting a print head having a plurality of nozzles for discharging a print recording liquid,
A printing recording liquid receiving area that is capable of receiving the printing recording liquid ejected from the nozzle and is divided by a predetermined boundary line into first and second areas having different electric field strengths generated between the printing head and the print head; ,
Print head driving means for discharging the printing recording liquid from the nozzle;
An electrical change detecting means for detecting an electrical change in the print recording liquid receiving area;
The print recording liquid charged from each nozzle in a nozzle row or nozzle row designed to be aligned in a predetermined direction with respect to the boundary line on the print head is sequentially discharged from the first area to the second area. An electrical change that occurs in the print recording liquid receiving area when the print head driving means is controlled is detected by the electrical change detecting means, and the nozzle row or the nozzle row is detected based on the detected electrical change. Control means for grasping a deviation from the predetermined direction of each nozzle forming
It is equipped with.

  In this print head inspection apparatus, the print recording liquid charged from each nozzle forming a nozzle row or nozzle row designed to be aligned in a predetermined direction with respect to the boundary line on the print head extends from the first region to the second region. An electrical change occurring in the printing recording liquid receiving area when sequentially ejected is detected, and a deviation from a predetermined direction of each nozzle in the nozzle row or nozzle row is grasped based on the detected electrical change. The electrical change at this time has different values at the boundary between the first and second regions. The reason is that an electrical change caused by electrostatic induction in the process where the charged printing recording liquid reaches the first area from the nozzle, and an electrostatic induction in the process where the charged printing recording liquid reaches the second area from the nozzle. The electric change that occurs is that the electric field strength generated between the print head and the first region differs from the electric field strength generated between the print head and the second region, and therefore has different values. For this reason, based on the electrical change detected in the print recording liquid receiving area, the print recording liquid discharged from the nozzles reaches either the first area or the second area across the boundary line where the nozzles should be arranged. You can see what happened. That is, if the nozzle arrangement is not deviated, it can be determined whether or not the printing recording liquid has reached the area that should be originally reached. As described above, when the print recording liquid is ejected, it is possible to know whether the print recording liquid has reached the area that should be originally reached by design, so it is possible to more quickly grasp the displacement of the nozzles of the print head. it can. Here, the “nozzle column or nozzle row” is sufficient if the nozzles are regularly arranged, and includes nozzles arranged in a straight line, a curved line, or the like.

  In the print head inspection apparatus of the present invention, the printing recording liquid receiving area may have a step as the boundary line. In this case, the distance between the print head and the first region and the distance between the print head and the second region are different from each other. The electric field strength between the two regions can be set to a different value.

  In the print head inspection apparatus according to the present invention, the print recording liquid receiving region may have one straight line as the boundary line, and the control means may be arranged in a direction parallel to the boundary line on the print head. The print head driving unit may be controlled to sequentially discharge the print recording liquid charged from each nozzle constituting the designed nozzle row or nozzle row from the first region to the second region. By doing so, it is easy to make the designed nozzle arrangement correspond to the boundary line of the print recording liquid receiving area, so that it is possible to accurately grasp the displacement of the nozzles of the print head.

  In the print head inspection apparatus according to the present invention, the print recording liquid receiving area may have an edge of a predetermined inspection plate arranged so as to cover a part of the print recording liquid receiving area as the boundary line. In this case, the printing recording liquid receiving area can be easily divided into the first area and the second area by using the edge of the inspection plate as a boundary line. Here, the “inspection plate” may be formed of a glass plate, a metal plate, a resin plate, paper, or the like, or may be formed of a plate-like body (for example, sponge) made of a material capable of absorbing the printing recording liquid. Also good. At this time, the print head inspection apparatus of the present invention includes a print head moving unit capable of moving the print head in a main scanning direction substantially orthogonal to a conveyance direction of a print medium on which an image is printed, and the print recording liquid receiving region Uses the conveyance-side edge of the inspection plate formed to be parallel to the conveyance direction as the boundary line, and the control means is a direction parallel to the boundary line by the conveyance-side edge on the print head. And controlling the print head driving means so as to sequentially discharge the print recording liquid charged from each nozzle constituting the nozzle array designed to line up from the first area to the second area. The print head moving means may be controlled to move in the main scanning direction. In this way, since the print head can be moved in the main scanning direction, the nozzle can be moved relatively easily in the main scanning direction with respect to the boundary line where the nozzles should be arranged. In addition, since the conveyance-side edge of the inspection plate formed so as to be parallel to the conveyance direction is used as a boundary line, it is possible to grasp the displacement of the arrangement of the nozzles arranged in the conveyance direction with a relatively simple configuration. . Alternatively, the print head inspection apparatus according to the present invention includes a transport unit capable of transporting the inspection plate in a transport direction of a print medium on which an image is printed, and the print recording liquid receiving region is configured to have the nozzles arranged therein. The main scanning side edge of the inspection plate formed to be parallel to the main scanning direction is defined as the boundary line, and the control means is a direction parallel to the boundary line by the main scanning side edge on the print head. The print head driving means is controlled so as to sequentially discharge the print recording liquid charged from the respective nozzles in the nozzle rows designed to be arranged in a row from the first area to the second area, and the inspection plate You may control the said conveyance means so that it may convey in the said conveyance direction. In this way, since the inspection plate can be moved in the transport direction, the boundary line where the nozzles should be arranged can be moved relatively easily in the transport direction with respect to the print head. In addition, since the main scanning side edge of the inspection plate formed so as to be parallel to the main scanning direction is used as the boundary line, the displacement of the nozzles arranged in the main scanning direction can be grasped with a relatively simple configuration. be able to.

  In the print head inspection apparatus of the present invention, the control means may grasp the inclination of the print head based on the electrical change detected by the electrical change detection means. In this way, the print recording liquid itself ejected from the nozzles is directly used to grasp the inclination of the print head, so that it is possible to grasp the inclination of the print head with higher accuracy than indirect determination of the inclination of the print head. it can.

  The print head inspection apparatus of the present invention may include output means for outputting information relating to the displacement of the nozzles ascertained by the control means. In this way, it is easy to use the information regarding the displacement of the output nozzle arrangement. Here, the “output unit” is, for example, a unit that displays and outputs information on the displacement of the nozzles, a unit that outputs audio information on the displacement of the nozzles, and prints information on the displacement of the nozzles on the print medium. It may be a means for outputting.

  In the print head inspection apparatus of the present invention, the control means controls the print head driving means so that the print recording liquid is discharged toward the print recording liquid receiving area for each of the plurality of nozzles of the print head. An inspection may be performed as to whether or not the printing recording liquid is normally ejected from the nozzles based on the detection result of the electrical change detection means. In this way, the test of whether or not the print recording liquid is normally ejected from the print head and the inspection of the displacement of the nozzle arrangement can be performed in the same print recording liquid receiving area, so the print recording liquid is ejected normally. There is no need to newly provide a region for checking whether or not.

  The print head inspection apparatus of the present invention includes a potential difference generating unit that generates a predetermined potential difference between the print head and the print recording liquid receiving area and charges the print recording liquid before being discharged from the nozzle, The potential difference generating means controls the print head driving means to sequentially discharge the printing recording liquid from the first area to the second area, and between the printing head and the printing recording liquid receiving area. In addition, the predetermined potential difference may be generated and the printing recording liquid before discharging from the nozzle may be charged.

  A printing apparatus according to the present invention includes a print head including a plurality of nozzles that discharge the printing recording liquid, and the print head inspection apparatus described above. Since the print head inspection apparatus of the present invention can grasp the displacement of the nozzles of the print head more quickly as described above, the printing apparatus having the same can obtain the same effect.

The print head inspection method of the present invention includes:
A print head having a plurality of nozzles for discharging a print recording liquid can receive the print recording liquid discharged from the nozzles, and first and second electric field strengths generated between the print head and the print head are different from each other. A print head inspection method for inspecting using a print recording liquid receiving area divided by a predetermined boundary line in an area,
(A) The printing recording liquid charged from each nozzle forming a nozzle row or a nozzle row designed to be arranged in a predetermined direction with respect to the boundary line on the print head from the first region to the second region. A step of sequentially discharging over,
(B) detecting an electrical change occurring in the printing recording liquid receiving area during the execution of the step (a);
(C) grasping a deviation from the predetermined direction of each nozzle forming the nozzle row or the nozzle row based on the electrical change detected in the step (b);
Is included.

  In this print head inspection method, the print recording liquid charged from each nozzle forming a nozzle row or nozzle row designed to be aligned in a predetermined direction with respect to the boundary line on the print head extends from the first region to the second region. An electrical change occurring in the printing recording liquid receiving area when sequentially ejected is detected, and a deviation from a predetermined direction of each nozzle in the nozzle row or nozzle row is grasped based on the detected electrical change. The electrical change at this time has different values at the boundary between the first and second regions. The reason is that an electrical change caused by electrostatic induction in the process where the charged printing recording liquid reaches the first area from the nozzle, and an electrostatic induction in the process where the charged printing recording liquid reaches the second area from the nozzle. The electric change that occurs is that the electric field strength generated between the print head and the first region differs from the electric field strength generated between the print head and the second region, and therefore has different values. For this reason, based on the electrical change detected in the print recording liquid receiving area, the print recording liquid discharged from the nozzles reaches either the first area or the second area across the boundary line where the nozzles should be arranged. You can see what happened. That is, if the nozzle arrangement is not deviated, it can be determined whether or not the printing recording liquid has reached the area that should be originally reached. As described above, when the print recording liquid is ejected, it is possible to know whether the print recording liquid has reached the area that should be originally reached by design, so it is possible to more quickly grasp the displacement of the nozzles of the print head. it can. In this print head inspection method, various aspects of the above-described print head inspection apparatus may be adopted, and steps for realizing each function of the above-described print head inspection apparatus may be added. .

  The program of the present invention is for causing one or more computers to implement each step of the above-described print head inspection method. This program may be recorded on a computer-readable recording medium (for example, hard disk, ROM, FD, CD, DVD, etc.), or from a computer via a transmission medium (communication network such as the Internet or LAN). It may be distributed to another computer, or may be exchanged in any other form. If this program is executed by one computer or if each computer is assigned to and executed by a plurality of computers, each step of the above-described print head inspection method is executed. Therefore, the same operation as the print head inspection method is performed. An effect is obtained.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram showing an outline of the configuration of an inkjet printer 20 including a print head inspection apparatus 50 according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of a print head 24, and FIG. FIG. 4 is an explanatory diagram of the paper feed mechanism 31, FIG. 4 is a configuration diagram showing an outline of the configuration of the print head inspection device 50, FIG. 5 is an explanatory diagram of the inspection plate 60, and FIG. It is a top view when arrange | positioned on the top, (b) is AA sectional drawing of (a).

  As shown in FIG. 1, the inkjet printer 20 of the present embodiment includes a printer mechanism 21 including a print head 24 and a carriage 22, and a paper feed mechanism 31 including a paper feed roller 35 driven by a drive motor 33. A cap device 40 formed in the vicinity of the right end of the platen 44, a print head inspection device 50 for inspecting the print head 24 using ink droplets formed in the vicinity of the center of the platen 44 and ejected from the print head 24, And a controller 70 for controlling the entire inkjet printer 20. In addition, an operation panel 78 that displays information about the ink jet printer 20 is disposed outside the housing. The core components of the present invention are the print head inspection device 50 and the print head 24, but other configurations will be described in sequence.

  The printer mechanism 21 includes a carriage 22 that reciprocates in the left-right direction (main scanning direction) along a guide 28 by a carriage belt 32 and a carriage motor 34, and mounted on the carriage 22 with yellow (Y), magenta (M), An ink cartridge 26 that individually accommodates ink of each color of cyan (C) and black (K), a print head 24 that applies pressure to each ink supplied from each ink cartridge 26, and a pressure applied by the print head 24 Nozzles 23 for discharging the ink droplets onto the recording paper S, and a platen 44 as a support member for supporting the recording paper S being printed. A linear encoder 25 that detects the position of the carriage 22 is disposed in the vicinity of the carriage 22, and the position of the carriage 22 can be managed using the linear encoder 25. Although not shown, the ink cartridge 26 is used for printing of cyan (C), magenta (M), yellow (Y), black (K), etc. containing a dye or pigment as a colorant in water as a solvent. The container is configured as a container for storing ink as a recording liquid, and is detachably attached to the carriage 22. A flushing region 42 is formed near the left end of the platen 44. The flushing region 42 is used when performing a so-called flushing operation in which ink droplets are ejected at a regular or predetermined timing regardless of print data in order to prevent ink from drying and solidifying at the tip of the nozzle 23. Used.

  Here, since many components (such as the carriage 22) of the printer mechanism 21 are well known, detailed description thereof will be omitted, and the print head 24 highly relevant to the present invention will be described below. As shown in FIG. 2, the print head 24 includes a nozzle row 43 in which a plurality of nozzles 23 that discharge inks of cyan (C), magenta (M), yellow (Y), and black (K) are arranged. Is provided. Here, all nozzles are collectively referred to as nozzles 23, all nozzle rows are collectively referred to as nozzle rows 43, cyan nozzles and nozzle rows are nozzles 23C and 43C, magenta nozzles and nozzle rows are nozzles 23M. The nozzle row 43M, the yellow nozzle and the nozzle row are referred to as a nozzle 23Y and a nozzle row 43Y, and the black nozzle and the nozzle row are referred to as a nozzle 23K and a nozzle row 43K. Further, the nozzle group of the nozzle row number n included in each nozzle row 43 is referred to as a nozzle row 45 with respect to the nozzle row 43. A nozzle row number n and a nozzle row number m are assigned to the nozzles 23 included in the print head 24 in order to specify the nozzles. In this embodiment, since the nozzle row 43 is composed of 180 nozzles, the nozzle row number n is an integer value from 1 to 180, and the nozzle row 45 is composed of four color columns, so the nozzle row number m is It is an integer value from 1 to 4. Hereinafter, description will be given using the nozzle 23K. In the print head 24, 180 nozzles 23 </ b> K are arranged along the conveyance direction of the recording paper S to form a nozzle row 43 </ b> K. The nozzle 23K is provided with a piezoelectric element 48 as a drive element for ejecting ink droplets. By applying a voltage to the piezoelectric element 48, the piezoelectric element 48 is deformed to pressurize and eject ink from the nozzle 23K. To do.

  The print head 24 includes a plurality of mask circuits 47 provided corresponding to the plurality of piezoelectric elements 48 that drive the respective nozzles 23K. The original signal ODRV and the print signal PRTn generated by the controller 70 are input to the mask circuit 47. Note that n at the end of the print signal PRTn is a number (nozzle row number n) for specifying the nozzles included in the nozzle row 43. This original signal ODRV has a first pulse P1, a second pulse P2, a third pulse P3, as shown in the lower part of FIG. 2, within a period of one pixel (within the time during which the carriage 22 crosses the interval of one pixel). It consists of three drive waveforms. In the present embodiment, the original signal ODRV having these three drive waveforms as a repeating unit is referred to as one segment. When the original signal ODRV and the print signal PRTn are input, the mask circuit 47 transmits a necessary pulse among the first pulse P1, the second pulse P2, and the third pulse P3 based on these signals to the drive signal DRVn (n Is the same as n of the print signal PRTn) and is output toward the piezoelectric element 48 of the nozzle 23K. Specifically, when only the first pulse P1 is output from the mask circuit 47 to the piezoelectric element 48, one shot of ink droplet is ejected from the nozzle 23K, and a small size dot (small dot) is formed on the recording paper S. It is formed. When the first pulse P1 and the second pulse P2 are output to the piezoelectric element 48, two shots of ink droplets are ejected from the nozzle 23K, and medium-sized dots (medium dots) are formed on the recording paper S. The When the first pulse P1, the second pulse P2, and the third pulse P3 are output to the piezoelectric element 48, three shots of ink droplets are ejected from the nozzle 23K, and a large size dot (large size) is formed on the recording paper S. Dot) is formed. Thus, in the inkjet printer 20, it is possible to form dots of three types of sizes by adjusting the amount of ink ejected in one pixel section. The other color nozzles 23C, 23M, and 23Y and the nozzle rows 43C, 43M, and 43Y are the same as the nozzle 23K and the nozzle row 43K. Here, the print head 24 employs a method in which the piezoelectric element 48 is deformed to pressurize the ink, but the ink is generated by bubbles generated by heating the ink by applying a voltage to a heating resistor (for example, a heater). You may employ | adopt the system which pressurizes.

  As shown in FIG. 3, the paper feed mechanism 31 includes a recording paper insertion port 18 for inserting the recording paper S placed on the paper feed tray 14 and a recording paper S placed on the paper feed tray 14 as a print head. A paper feed roller 36 for feeding the recording paper S and roll paper to the print head 24, and a paper discharge roller 37 for discharging the recording paper S after printing. The paper feed roller 36, paper feed roller 35, and paper discharge roller 37 are driven by a drive motor 33 (see FIG. 1) via a gear mechanism (not shown). A plurality of recording sheets S are prevented from being fed at a time by the rotational driving force of the sheet feeding roller 36 and the frictional resistance of a separation pad (not shown).

  The print head inspection device 50 forms the core of the present invention. As shown in FIG. 4, the print head inspection device 50 is provided in the inspection box 51 and the inspection box 51 in which ink droplets flying from the nozzles 23 of the print head 24 can land. The ink receiving area 52, a voltage applying circuit 53 for applying a voltage between the ink receiving area 52 and the print head 24, and a voltage detecting circuit 54 for detecting the voltage of the ink receiving area 52. The inspection box 51 is a housing that is provided at substantially the center of the printable area of the platen 44 and is substantially rectangular parallelepiped and opened at the top. The ink receiving area 52 is provided in the inspection box 51 and has an upper ink absorber 55 on which ink droplets directly land, and a lower side that absorbs ink droplets that have permeated downward after landing on the upper ink absorber 55. The ink absorber 56 is configured by a mesh-like electrode member 57 disposed between the upper ink absorber 55 and the lower ink absorber 56. The upper ink absorber 55 is made of a conductive sponge so as to have the same potential as the electrode member 57. This sponge is highly permeable so that the landed ink droplets can move down quickly, and here, an ester urethane sponge (trade name: Everlite SK-E, manufactured by Bridgestone Corporation) is used. Yes. The lower ink absorber 56 has higher ink retention than the upper ink absorber 55 and is made of a nonwoven fabric such as felt. Here, the nonwoven fabric (trade names: Kinocloth, Oji Kinocross Co., Ltd.) Made). The electrode member 57 is formed as a grid-like mesh made of a metal made of stainless steel (for example, SUS). For this reason, the ink once absorbed by the upper ink absorber 55 is absorbed and held by the lower ink absorber 56 through the gap between the grid-like electrode members 57. The length of the ink receiving area 52 in the transport direction is designed to be longer than that of the nozzle row 43, and the length of the ink receiving area 52 in the main scanning direction is designed to be longer than that of the print head 24. The upper ink absorber 55 may be made of a material that does not have conductivity and may have conductivity by being wetted with liquid.

  The voltage application circuit 53 is electrically connected via a direct current power source (for example, 400 V) and a resistance element (for example, 1 MΩ) so that the electrode member 57 is a positive electrode and the print head 24 is a negative electrode. Here, since the electrode member 57 is in contact with the conductive upper ink absorber 55, the surface of the upper ink absorber 55 has the same potential as the electrode member 57. The voltage application circuit 53 has a switch SW for opening and closing the circuit. The switch SW is turned on when a main routine described later is executed, but is turned off in other cases. The voltage detection circuit 54 is connected so as to detect the voltage of the electrode member 57 equated with the voltage of the ink receiving area 52, integrates and outputs the voltage signal of the electrode member 57, and the integration circuit 54a. And an A / D conversion circuit 54c for A / D converting the signal output from the inverting amplification circuit 54b and outputting it to the controller. . The integration circuit 54a outputs a large voltage change by integrating the voltage change due to the flight / landing of a plurality of ink droplets ejected from the same nozzle 23 because the voltage change due to the flight / landing of one ink droplet is small. To do. The inverting amplifier circuit 54b inverts the sign of the voltage change and amplifies and outputs the signal output from the integrating circuit 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 the digital signal to the controller 70.

  As shown in FIG. 5, the inspection plate 60 is a resin flat plate formed in a predetermined size (for example, A4 size), and is used when a nozzle arrangement inspection routine described later is executed. A rectangular first slit 62 longer than the depth of the ink receiving area 52 in the transport direction is formed in the vicinity of the center of the tip of the inspection plate 60, and main scanning is performed upstream of the first slit 62 in the transport direction. A rectangular second slit 64 longer than the width of the ink receiving area 52 in the direction is formed. The first slit 62 is formed so that when the left end portion of the inspection plate 60 is transported along the reference guide, the transport-side edge 63 that is the right edge in FIG. 5 passes through the approximate center of the print head inspection apparatus 50. ing. The transport side edge 63 is formed to be parallel to the direction in which the nozzle rows 43 are arranged by design. The second slit 64 is formed so as to pass right above the print head inspection apparatus 50 when the left end portion of the inspection plate 60 is conveyed along the reference guide. Of the edges of the second slit 64, the main scanning side edge 65 on the downstream side in the transport direction is formed to be parallel to the direction in which the nozzle rows 45 are arranged in design.

  As shown in FIG. 1, the cap device 40 is used when sealing the nozzles 23 in order to prevent the nozzles 23 from being dried during a printing pause or the like. The cap device 40 is operated so as to cover the nozzle formation surface of the print head 24 when the print head 24 moves together with the carriage 22 to the right end (referred to as a home position). The cap device 40 is connected to a suction pump (not shown). For example, when the ink clogging of the nozzle is detected by the print head inspection device 50, a negative pressure of the suction pump is applied to the nozzle formation surface of the print head 24 sealed by the cap device 40 as necessary. The ink clogged from the nozzle 23 is sucked and discharged. Note that the waste ink discharged and collected is stored in a waste liquid tank (not shown).

  As shown in FIG. 1, the controller 70 is configured as a microprocessor centered on the CPU 72, and includes a ROM 73 that stores various processing programs, a RAM 74 that temporarily stores data and stores data, An interface (I / F) 79 for exchanging information with an external device and an input / output port 77 for exchanging signals with the constituent devices of the inkjet printer 20 are provided. The ROM 73 stores processing programs such as a main routine, an ink discharge inspection routine, and a nozzle arrangement inspection routine which will be described later. A voltage signal output from the voltage detection circuit 54 of the print head inspection apparatus 50 and a position signal from the linear encoder 25 are input to the controller 70 via the input / output port 77. The controller 70 outputs a drive signal to the print head 24, a signal to the cap device 40, a display output signal to the operation panel 78, and the like via the input / output port 77.

  Next, the operation of the ink jet printer 20 of the present embodiment configured as described above will be described. Here, the operation of the main routine will be described first. FIG. 6 is a flowchart of a main routine executed by the CPU 72 of the controller 70. This routine is stored in the ROM 73, and is executed by the CPU 72 after receiving an inspection command from the operator PC 10 when the inkjet printer 20 is inspected before shipment. When this routine is started, the CPU 72 first starts an ink ejection inspection routine (step S100). The operator starts the main routine after arranging the inspection plate 60 used in the nozzle arrangement inspection routine on the paper feed tray 14.

  Here, the ink ejection inspection routine will be described. As shown in FIG. 7, this routine is a process for inspecting / recovering whether or not all nozzles 23 arranged in the print head 24 are clogged, and is stored in the ROM 73. FIG. 7 is a flowchart of an ink discharge inspection routine. When this routine is started, the CPU 72 first turns on the switch SW of the voltage application circuit 53 and obtains the current inspection position, that is, the position of the ink receiving area 52 that ejects ink from the nozzle 23 (step S200). . Here, the inspection position is set at approximately the center of the ink receiving area 52. In this ink discharge inspection routine, the process is executed without the inspection plate 60 being placed on the platen 44 (see FIG. 4).

  Subsequently, the carriage motor 34 is driven to move the carriage 22 so that the nozzle row 43 to be inspected out of the nozzle rows 43 of the print head 24 faces the inspection position (step S210), and the nozzle to be inspected The ink droplet charged from the nozzle 23 is ejected through the mask circuit 47 and the piezoelectric element 48 (see FIG. 2) of one nozzle 23 in the row 43 (step S220). The voltage of the ink receiving area 52 changes until the negatively charged ink droplets fly from the nozzles 23 and land on the ink receiving area 52. The cause of the voltage change in the ink receiving area 52 is considered to be due to the following description.

  Here, the transition of the voltage in the electrode member 57 when the charged ink droplets fly from the nozzles 23 of the print head 24 and reach the upper ink absorber 55 in the ink receiving area 52 will be described with reference to FIG. FIG. 8 is an explanatory diagram of the principle that an induced voltage is generated by electrostatic induction. As shown in FIG. 8A, the ink droplet before flying from the nozzle 23 by the print head 24 is negatively charged by the voltage application circuit 53. For this reason, as shown in FIG. 8B, as the negatively charged ink droplets fly from the nozzle 23 and approach the upper ink absorber 55, the surface of the upper ink absorber 55 is positively applied by electrostatic induction. The charge increases. As a result, the voltage between the print head 24 and the electrode member 57 becomes higher than the initial voltage value due to the induced voltage generated by electrostatic induction. Thereafter, as shown in FIG. 8C, when the negatively charged ink droplet reaches the upper ink absorber 55, the positive charge of the upper ink absorber 55 is neutralized by the negative charge of the ink droplet. As a result, the voltage between the print head 24 and the electrode member 57 is lower than the initial voltage value. Thereafter, the voltage between the print head 24 and the electrode member 57 returns to the initial voltage value. The amplitude of the output signal at this time depends not only on the distance from the print head 24 to the upper ink absorber 55 (ink receiving area 52), but also on the presence / absence, number, and size of flying ink droplets. 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 becomes smaller than the normal time. The presence or absence of clogging can be determined. In the present embodiment, even if the ink droplet has a predetermined size, the amplitude of the output signal from the ink droplet for one shot is extremely small, so the number of ink ejections is set to 24 shots. With this number of ejections, 24 shots of ink droplets are ejected by performing the operation of outputting all of the first to third pulses P1, P2, P3 of one segment representing the drive waveform eight times. As a result, the output signal becomes an integrated value of ink droplets for 24 shots, and thus a sufficiently large output waveform can be obtained from the voltage detection circuit 54. Note that the direction of the amplitude of the signal output from the voltage detection circuit 54 is reversed because it passes through the inverting amplification circuit 54b (see FIG. 8).

  In step S220, the charged ink droplet is discharged from the nozzle 23 via the mask circuit 47 or the piezoelectric element 48 of one nozzle 23 in the nozzle row 43 to be inspected, and then output from the voltage detection circuit 54. It is determined whether or not the maximum voltage value is equal to or greater than a threshold value Vthr (step S230). This threshold value Vthr is a value that is determined empirically so that the maximum value of the voltage can exceed when ink is ejected normally. If the amplitude of the output signal is less than the threshold value Vthr in step S230, it is considered that an abnormality such as clogging has occurred in the current nozzle 23, and information for identifying the nozzle 23 (for example, which nozzle in which nozzle row is located) Information) is stored in a predetermined area of the RAM 74 (step S240).

  After step S240 or when the amplitude of the output signal is greater than or equal to the threshold value Vthr in step S230 (that is, when the current nozzle 23 is normal), all nozzles 23 included in the nozzle row 43 currently inspected are inspected. If there is an uninspected nozzle 23 in the nozzle row currently being inspected (step S250), the nozzle 23 to be inspected is updated to an uninspected nozzle (step S260), and then again in step S220. Processing of ~ S260 is performed. On the other hand, when all the nozzles 23 included in the nozzle row currently being inspected have been inspected in step S250, it is determined whether or not all the nozzle rows 43 included in the print head 24 have been inspected (step S270). When there is an uninspected nozzle row 43, the nozzle row 43 to be inspected is updated to the uninspected nozzle row 43 (step S280), and then the processes of steps S210 to S280 are performed again. On the other hand, when all the nozzle arrays 43 included in the print head 24 have been inspected in step S270, the CPU 72 turns off the switch SW of the voltage application circuit 53 (step S290), and ends this ink ejection inspection routine.

  Returning to the main routine of FIG. 6, after performing the above-described ink ejection inspection (step S100), whether or not there is a nozzle 23 in which ejection abnormality has occurred among all the nozzles 23 arranged in the print head 24. Is determined based on the contents stored in a predetermined area of the RAM 74 (step S110), and when there is a nozzle 23 in which ejection abnormality has occurred, the print head 24 is cleaned in consideration of clogging. However, it is determined whether or not the number of previous cleanings is less than a predetermined number (for example, three times) (step S120). When the number of cleanings is less than the predetermined number, the print head 24 is cleaned (step S130). Specifically, the carriage motor 34 is driven to move the carriage 22 until the print head 24 comes to the home position facing the cap device 40, and the cap device 40 is operated so that the cap device 40 forms the nozzles of the print head 24. After covering the surface, the negative pressure of a suction pump (not shown) is applied to the nozzle forming surface to suck and discharge the clogged ink from the nozzle 23. After executing this cleaning, the process returns to step S100 again to check whether or not the ejection abnormality of the nozzle 23 has been eliminated. In this step S100, only the nozzles 23 in which the ejection abnormality has occurred may be re-inspected. However, the nozzles 23 that were normal at the time of cleaning may be clogged for some reason. Re-inspection is performed for all 24 nozzles 23. On the other hand, if the number of cleanings performed in step S120 is equal to or greater than the predetermined number, it is assumed that the nozzles 23 in which the ejection abnormality has occurred are not normalized even if cleaning is performed, and an error occurs in the operation panel 78 via the input / output port 77. A message is displayed and output (step S140), and this main routine is terminated.

  On the other hand, when there is no abnormal nozzle 23 in step S110, a nozzle arrangement inspection routine, which is the core control of the present invention, is executed (step S150). FIG. 9 is a flowchart of a nozzle arrangement inspection routine. As shown in FIG. 9, this nozzle arrangement inspection routine is a process for grasping the deviation from the predetermined direction of the nozzles 23 that are designed to be arranged in a predetermined direction, and is stored in the ROM 73. When this nozzle arrangement inspection routine is started, the CPU 72 first turns on the switch SW of the voltage application circuit 53 to cause a predetermined potential difference between the print head 24 and the upper ink absorber 55 by the voltage application circuit 53. In step S300, the inspection plate 60 is moved to the first inspection position in order to inspect the displacement of the nozzles 23 arranged in the transport direction (row direction) included in the print head 24. It is moved by driving (step S310). Here, it is assumed that the inspection plate 60 is conveyed in parallel to the reference guide. Further, the first inspection position is set to a position where the first slit 62 formed in the inspection plate 60 comes above the print head inspection apparatus 50 (see FIG. 5A). As described above, when the inspection plate 60 is disposed at the first inspection position, the conveyance-side edge 63 serves as a boundary line, and the upper surface of the inspection plate 60 forms a part of the ink receiving area 52. A step is formed between the upper surface of the upper ink absorber 55 and the surface of the upper ink absorber 55. The upper surface of the upper inspection plate 60 that forms a step becomes the first region 52 a in the ink receiving region 52, and the surface of the lower upper ink absorber 55 becomes the second region 52 b in the ink receiving region 52. Note that the inspection plate 60 that forms part of the ink receiving area 52 is at the same potential as the print head 24, for example, in a grounded state.

  Next, the CPU 72 moves the carriage 22 to the ink ejection position based on the value of the linear encoder 25 (step S320). In the initial state, the ink ejection position is determined in the vicinity of the conveyance-side edge 63 on the inspection plate 60 (see FIG. 10A described later). Here, the carriage 22 is moved so that the nozzle row 43Y of the print head 24 faces this position. Subsequently, the CPU 72 controls the mask circuit 47 and the piezoelectric element 48 to discharge charged ink droplets from the nozzle 23 to be inspected (step S330). Here, the nozzle 23 to be inspected is set to discharge from the nozzle 23 with the nozzle row number n = 1 included in the nozzle row 43 with the nozzle row number m = 1 (nozzle row 43Y) at the start of inspection. The number of ink droplets discharged is set to 24 shots (8 segments). The number of ink ejections may be any ejection number that can accurately detect the landing of ink droplets on the ink receiving area 52, and may be less than 24 shots.

  Subsequently, the CPU 72 is ejected based on whether or not the electrostatic induction voltage output generated when the ink droplet reaches the upper ink absorber 55 in the ink receiving area 52 is equal to or higher than a predetermined threshold value Vref. It is determined whether the ink droplet has landed on the first area 52a or the second area 52b, and the determination result is stored in the RAM 74 (step S340). The predetermined threshold value Vref cannot exceed the maximum value of the voltage output from the voltage detection circuit 54 when the ejected ink droplet has landed on the first region 52a, and the voltage is detected when it has landed on the second region 52b. This value is determined empirically so that the maximum value of the voltage output from the circuit 54 can be exceeded. Using this threshold value Vref, it is determined whether the ejected ink droplet has landed on the first or second region 52a, 52b.

  After the processing in step S340, the CPU 72 determines whether or not the processing has been performed for all the nozzles 23 included in the nozzle row 43 currently inspected (step S350). When there is an inspection nozzle 23, the nozzle 23 to be inspected is updated to an uninspected nozzle (step S360), and then the processing of steps S330 to S360 is performed again. The nozzles 23 to be inspected are set so as to be sequentially changed from nozzle row numbers n = 1 to n = 180. On the other hand, when all the nozzles 23 included in the nozzle row 43 currently inspected are inspected in step S350, it is determined whether or not the print head 24 has moved within a predetermined inspection range (step S370). This predetermined inspection range is defined as a range in which the nozzle row 43 to be inspected moves from the first region 52a to the second region 52b across the boundary line. That is, it is determined whether or not ink droplets have been ejected from all the nozzles 23 included in the nozzle row 43 from the first region 52a to the second region 52b. When the print head 24 has not moved within the predetermined inspection range, the CPU 72 moves the print head 24 by a predetermined amount (step S320). The predetermined amount of movement of the print head 24 in step S320 here is set to move a minute amount smaller than the size of the nozzle 23 (for example, 1/4 nozzle). Subsequently, the CPU 72 performs the processes of steps S330 to S370. That is, each time the print head 24 is moved by a small amount until the print head 24 moves in a predetermined inspection range in step S370, ink droplets are sequentially ejected from the nozzles 23Y of the nozzle row numbers n = 1 to 180. The position where the ink droplets landed is stored in the RAM 74.

  On the other hand, when the print head 24 moves in a predetermined inspection range in step S370, the CPU 72 determines whether or not all nozzle arrays 43 included in the print head 24 have been inspected (step S380), and uninspected. When the nozzle row 43 exists, the nozzle row 43 to be inspected is updated to the uninspected nozzle row 43 (step S390). Here, the update of the uninspected nozzle row 43 is set so that the nozzle row numbers m = 1 to m = 4 are sequentially changed. Thereafter, the processes of steps S320 to S390 are performed again. That is, for each nozzle row 43, each time the print head 24 is moved by a small amount until the nozzle row 43 to be inspected moves within a predetermined inspection range from the first region 52a to the second region 52b as described above. Ink droplets are sequentially ejected from the nozzles 23 of line numbers n = 1 to 180, and the positions where the ejected ink droplets land are stored in the RAM 74.

  Here, the processing of steps S320 to S390 will be described with reference to FIGS. FIG. 10 is an explanatory diagram of a series of processes for detecting the deviation of the individual nozzles 23 included in the nozzle row 43. FIG. 11 detects the deviation of the nozzles 23 when the print head 24 is disposed at an inclination. It is explanatory drawing of a series of processes. 10 and 11, a part of the inspection plate 60 near the print head 24 is displayed. As shown in FIG. 10A, first, the nozzle row 43Y is arranged so as to face the position in the vicinity of the conveyance side edge 63 on the inspection plate 60, and the nozzle row numbers n = 1 to n = in the nozzle row 43Y. The ink droplets are sequentially ejected from the nozzle 23Y up to 180. At this time, when the ejected ink droplets land on the first region 52a, the output voltage detected by the voltage detection circuit 54 becomes less than the threshold value Vref, so that the ink droplets ejected from each nozzle are in the first region 52a. Is stored in the RAM 74 as having been landed. Note that the balloon in FIG. 10A means that the output voltage is less than the threshold value Vref. Next, the print head 24 is moved by a small amount to sequentially eject ink droplets from the nozzles 23Y from n = 1 to n = 180. Subsequently, as shown in FIG. 10B, when the output voltage detected by the voltage detection circuit 54 is equal to or higher than the threshold value Vref (see the balloon), the nozzle 23Y (here, the nozzle row number) from which this output voltage is detected. n = 2) is stored in the RAM 74 as an ink droplet landing on the second region 52b. At this time, for the nozzles 23Y whose output voltage detected by the voltage detection circuit 54 is less than the threshold value Vref, the ink droplets ejected from the respective nozzles are stored in the RAM 74 as having landed on the first region 52a. In some cases, some of the ejected ink droplets are on the boundary line. In this case, some of the ejected ink droplets land on the first region 52a and all of them reach the second region 52b. Therefore, it is determined that the ink droplet has landed on the first region 52a without the output voltage exceeding the threshold value Vref. Subsequently, when the print head 24 is moved and ink droplets are ejected, as shown in FIG. 10C, the output voltage detected by the voltage detection circuit 54 at all the nozzles 23Y becomes equal to or higher than the threshold value Vref (see the balloon). The RAM 74 stores the ink droplets that have landed on the second region 52b. Subsequently, the same processing is sequentially performed for the nozzle rows 43C, 43M, and 43K after the nozzle row number m = 2. In this way, the induced voltage when ink droplets are ejected from the nozzle 23Y from the first region 52a to the second region 52b via the conveyance-side edge 63 as a boundary line where the nozzles 23 should be arranged by design is detected. Based on the detected content, the landing position of the ink droplet is stored in the RAM 74. At this time, in many nozzles 23Y, the induced voltage is less than the threshold value Vref while exceeding the threshold value Vref, or in many nozzles 23Y, the induced voltage is less than the threshold value Vref while the induced voltage is greater than or equal to the threshold value Vref. About things, it can grasp that it has shifted from the arrangement direction on the design.

  Next, the case where the print head 24 is inclined will be described. As shown in FIG. 11A, the CPU 72 first arranges the nozzle row 43Y so as to face the position in the vicinity of the conveyance side edge 63 on the inspection plate 60, and the nozzle row number n = 1 in the nozzle row 43Y. To n = 180, ink droplets are sequentially ejected from the nozzle 23Y. At this time, if the output voltage detected by the voltage detection circuit 54 is equal to or higher than the threshold value Vref, the nozzles 23Y (here, the nozzle row number n = 1) are stored in the RAM 74 as ink drops having landed in the second region 52b. Remember. On the other hand, when the output voltage detected by the voltage detection circuit 54 is less than the threshold value Vref, the ink droplet ejected from the nozzle 23 is stored in the RAM 74 as having landed on the first region 52a. Next, the print head 24 is moved by a small amount to sequentially eject ink droplets from the nozzles 23Y from n = 1 to n = 180, and the output voltage detected by the voltage detection circuit 54 as shown in FIG. Is greater than or equal to the threshold value Vref, the nozzle 23Y (nozzle row number n = 1, 2 here) is stored in the RAM 74 as an ink droplet landing on the second region 52b. Subsequently, when the print head 24 is moved and ink droplets are ejected, as shown in FIG. 11C, if the output voltage detected by the voltage detection circuit 54 is equal to or higher than the threshold value Vref, the nozzle 23Y (here, Nozzle row numbers n = 1, 2, 3) are stored in the RAM 74 as ink droplets having landed in the second region 52b. Subsequently, the same processing is sequentially performed for the nozzle rows 43C, 43M, and 43K after the nozzle row number m = 2. In this way, the induced voltage when ink droplets are ejected from the nozzle 23Y from the first region 52a to the second region 52b via the conveyance-side edge 63 as a boundary line where the nozzles 23 should be arranged by design is detected. Based on the detected content, the landing position of the ink droplet is stored in the RAM 74. At this time, when the number of nozzles 23 greater than or equal to the threshold value Vref increases every time the print head 24 moves a certain amount, it is possible to grasp that the arrangement of the nozzles 23 is shifted due to the inclination of the print head 24 itself. It is.

  On the other hand, when all the nozzle rows 43 included in the print head 24 have been inspected in step S380, the CPU 72 should inspect the displacement of the nozzles 23 arranged in the main scanning direction (row direction) included in the print head 24. The inspection plate 60 is moved to the second inspection position by driving the paper feed roller 36 and the paper feed roller 35 (step S400). Here, the second inspection position is determined so that the main scanning side edge 65 of the second slit 64 formed in the inspection plate 60 is positioned above the end of the upper ink absorber 55 on the upstream side in the transport direction. ing. As described above, when the inspection plate 60 is arranged at the second inspection position, the main scanning side edge 65 serves as a boundary line, and the upper surface of the inspection plate 60 forms a part of the ink receiving area 52. A step is formed by the upper surface of 60 and the surface of the upper ink absorber 55. The upper surface of the upper inspection plate 60 that forms a step becomes the first region 52 a in the ink receiving region 52, and the surface of the lower upper ink absorber 55 becomes the second region 52 b in the ink receiving region 52.

  Next, the CPU 72 moves the carriage 22 to the ink ejection position based on the value of the linear encoder 25 (step S410). The ink ejection position is determined at a position where the print head 24 is disposed immediately above the upper ink absorber 55. Thus, the nozzle row 45 with the nozzle row number n = 180 is in a state of facing the upper surface of the inspection plate 60 in the vicinity of the main scanning side edge 65 (see FIG. 12A described later). In the inspection process of the displacement of the nozzles 23 arranged in the main scanning direction (steps S400 to S480), the print head 24 ejects ink droplets while being fixed at this position. Subsequently, the CPU 72 controls the mask circuit 47 and the piezoelectric element 48 to discharge charged ink droplets from the nozzle 23 to be inspected (step S420). Here, the nozzle 23 to be inspected is set to discharge from the nozzle 23 with the nozzle row number n = 180 included in the nozzle row 43 with the nozzle row number m = 1 (nozzle row 43Y) at the start of the inspection. The number of ink droplets discharged is set to 24 shots (8 segments). The number of ink ejections may be any ejection number that can accurately detect the landing of ink droplets on the ink receiving area 52, and may be less than 24 shots.

  Subsequently, the CPU 72 is ejected based on whether or not the electrostatic induction voltage output generated when the ink droplet reaches the upper ink absorber 55 in the ink receiving area 52 is equal to or higher than a predetermined threshold value Vref. It is determined whether the ink droplet has landed on the first area 52a or the second area 52b, and the determination result is stored in the RAM 74 (step S430). Note that the threshold Vref described above is used.

  After the processing in step S430, the CPU 72 determines whether or not the processing has been performed for all the nozzles 23 included in the nozzle row 45 currently inspected (step S440). When there is an inspection nozzle 23, the nozzle 23 to be inspected is updated to an uninspected nozzle (step S450), and then the processes of steps S420 to S450 are performed again. The nozzles 23 to be inspected are set so as to be sequentially changed from nozzle row numbers m = 1 to m = 4. On the other hand, when all the nozzles 23 included in the nozzle row 45 currently being inspected have been inspected in step S440, it is determined whether or not the inspection plate 60 has been conveyed within a predetermined inspection range (step S460). This predetermined inspection range is defined as a range in which the nozzle row 45 to be inspected moves relatively from the first region 52a to the second region 52b when the inspection plate 60 is conveyed. That is, it is determined whether or not ink droplets have been ejected from all the nozzles 23 included in the nozzle row 45 from the first region 52a to the second region 52b. When the inspection plate 60 is not transported through the predetermined inspection range, the CPU 72 transports the inspection plate 60 by a predetermined amount (step S470). The conveyance amount of the inspection plate 60 is set so as to convey a minute amount smaller than the size of the nozzle 23 (for example, 1/4 nozzle). Subsequently, the CPU 72 performs steps S420 to S470. That is, ink droplets are sequentially ejected from the nozzles 23Y of the nozzle row number m = 1 to 4 each time the inspection plate 60 is transported by a small amount until the inspection plate 60 is transported through a predetermined inspection range in step S460. The position where the ejected ink droplets land is stored in the RAM 74.

  On the other hand, when the inspection plate 60 is conveyed in the predetermined inspection range in step S460, the CPU 72 determines whether or not the inspection has been performed for all the nozzle rows 45 included in the print head 24 (step S480). When the inspection nozzle row 45 exists, the nozzle row 45 to be inspected is updated to an uninspected nozzle row 45 (step S490). Here, the update of the uninspected nozzle row 45 is set to sequentially change from nozzle row number n = 180 to n = 1. Thereafter, the processes in steps S420 to S490 are performed again. That is, for each nozzle row 45, each time the inspection plate 60 is transported by a small amount until the nozzle row 45 to be inspected moves relatively from the first region 52a to the second region 52b as described above, Ink droplets are sequentially ejected from the nozzles 23 of the numbers m = 1 to 4, and the positions where the ejected ink droplets land are stored in the RAM 74.

  Here, the processing in steps S420 to S490 will be described with reference to FIG. FIG. 12 is an explanatory diagram of a series of processes for detecting the displacement of the nozzles 23 included in the nozzle row 45. As shown in FIG. 12A, first, a nozzle row 45 (n = 180) is arranged so as to face a position near the main scanning side edge 65 on the inspection plate 60, and a nozzle column number in the nozzle row 45. Ink droplets are sequentially ejected from the nozzles 23 from m = 1 to m = 4. At this time, when the ejected ink droplets land on the first region 52a, the output voltage detected by the voltage detection circuit 54 is less than the threshold value Vref (see the balloon). Accordingly, the ink droplets ejected from each nozzle are stored in the RAM 74 as having landed on the first region 52a. Next, a small amount of the inspection plate 60 is conveyed, and ink droplets are sequentially ejected from the nozzles 23 from m = 1 to m = 4. Subsequently, as shown in FIG. 12B, when the output voltage detected by the voltage detection circuit 54 is equal to or higher than the threshold value Vref (see the balloon), this nozzle 23 (here, nozzle row number m = n = 1, 2 and 4) are stored in the RAM 74 as ink drops having landed in the second region 52b. On the other hand, for the nozzles 23 whose output voltage detected by the voltage detection circuit 54 is less than the threshold value Vref (here, nozzle row number m = 3), the ejected ink droplets are assumed to have landed on the first region 52a and stored in the RAM 74. Remembered. Subsequently, when the print head 24 is moved and ink droplets are ejected, as shown in FIG. 12C, the output voltage detected by the voltage detection circuit 54 at all the nozzles 23Y becomes equal to or higher than the threshold value Vref (see the balloon). The RAM 74 stores the ink droplets that have landed on the second region 52b. Subsequently, the same processing is sequentially performed for the nozzle rows 45 after the nozzle column number m = 179. In this way, the induced voltage is detected when ink droplets are ejected from the nozzles 23 from the first region 52a to the second region 52b via the main scanning side edge 65 as a boundary line where the nozzles 23 should be arranged by design. The ink droplet landing position is stored in the RAM 74 based on the detected content. At this time, the induced voltage is less than the threshold Vref while the induced voltage is greater than or equal to the threshold Vref in many nozzles 23, or the induced voltage is less than the threshold Vref while the induced voltage is less than the threshold Vref in many nozzles 23. About what is the above, it can grasp | ascertain that it has shifted | deviated from the arrangement direction on a design. In this process as well, it is possible to determine whether or not the print head 24 itself is tilted by the same process as in FIG.

  On the other hand, when there is no uninspected nozzle row 45 in step S480, the switch SW of the voltage application circuit 53 is turned off (step S500), and the inspection result stored in the RAM 74 is analyzed (step S510). Exit the routine. Specifically, the analysis of the inspection result is based on the information stored in the RAM 74, and the CPU 72 grasps the individual nozzles 23 deviating from the designed arrangement direction, or the print head 24 is inclined. Or figure out what is being done. At this time, in the deviation of the individual nozzles 23 with respect to the transport direction, for example, in FIG. 10B, after the nozzles 23 (n = 2) that are equal to or higher than the threshold Vref are detected, the nozzles 23 that are equal to or higher than the other threshold Vref are detected. The amount of movement of the print head 24 up to this time corresponds to the amount of deviation from the designed arrangement direction. Based on this, the amount of deviation of the nozzle 23 is calculated and stored in the RAM 74. Similarly, in the deviation of the individual nozzles 23 with respect to the main scanning direction, for example, in FIG. 12B, the nozzles 23 (m = 3) that are equal to or higher than the threshold Vref after the nozzles 23 that are equal to or higher than the other threshold Vref are detected. Since the conveyance amount of the inspection plate 60 until detection corresponds to the deviation amount from the arrangement direction, the deviation amount of the nozzle 23 is calculated based on this and stored in the RAM 74. Alternatively, in the inclination of the print head 24, for example, in FIG. 11B, after the nozzle 23 (n = 1) having a threshold value Vref or higher is detected, the nozzle 23 (n = 2) having the next threshold value Vref or higher is detected. The inclination angle θ of the print head 24 is calculated from the relationship between the movement amount of the print head 24 until the nozzle distance and the nozzle interval, and stored in the RAM 74.

  Returning to the main routine of FIG. 6, after performing the nozzle arrangement inspection routine (step S150) described above, it is determined whether or not there is an abnormally arranged nozzle 23 among all the nozzles 23 arranged in the print head 24, that is, Whether or not there is an individual nozzle 23 deviating from the designed arrangement direction is determined based on the stored contents of a predetermined area of the RAM 74 (step S160). Along with information such as the number, an error message to that effect is displayed on the operation panel 78 via the input / output port 77 (step S140), and this main routine is terminated. On the other hand, when there is no abnormally arranged nozzle 23 in step S160, it is determined whether the print head 24 is inclined or not based on the stored contents of a predetermined area of the RAM 74 (step S170), and the print head 24 is inclined. And an error message to that effect together with information such as the inclination angle θ of the print head 24 is displayed on the operation panel 78 via the input / output port 77 (step S140), and this main routine is terminated. . On the other hand, when the print head 24 is not disposed at an inclination, a message indicating that there is no displacement of the nozzles 23 is displayed on the operation panel 78 (step S180), and this routine is terminated.

  The operator confirms the information displayed on the operation panel 78, and when the print head 24 is tilted, the tilt of the print head 24 is adjusted based on the displayed tilt angle θ of the print head 24. The adjustment of the inclination of the print head 24 can be performed using an adjustment mechanism (not shown) provided in the carriage 22 that can adjust the inclination by operating the position of a screw or a lever, for example. Further, when there is a deviation of the individual nozzles 23, the following measures are executed. For example, the relationship between the displacement amount of the nozzles 23 and the printed image quality is obtained empirically, and the allowable displacement amount of the nozzles 23 allowed for the print image is determined in advance. Then, after the above-described inspection, the amount of deviation of the nozzle 23 is confirmed, and when the allowable deviation amount is exceeded, the print head 24 is determined to be defective. On the other hand, when the deviation amount of the nozzle 23 obtained by the inspection does not exceed the allowable deviation amount, it is determined that there is no possibility that the image quality of the printed matter is deteriorated, and the inspection is passed as it is.

  Here, the correspondence between the components of the present embodiment and the components of the present invention will be clarified. The ink receiving area 52 of this embodiment corresponds to the print recording liquid receiving area of the present invention, the mask circuit 47 and the piezoelectric element 48 correspond to the print head driving means, and the carriage belt 32 and the carriage motor 34 serve as the print head moving means. The paper feed roller 35, the paper feed roller 36, and the paper discharge roller 37 correspond to the conveying means, the voltage application circuit 53 corresponds to the potential difference generating means, the voltage detection circuit 54 corresponds to the electrical change detection means, The input / output port 77 corresponds to output means, and the CPU 72 corresponds to control means. Further, the ink of this embodiment corresponds to the printing recording liquid of the present invention, and the recording paper S corresponds to the printing medium. In the present embodiment, an example of the print head inspection method of the present invention is also clarified by describing the operation of the inkjet printer 20.

  According to the ink jet printer 20 of the present embodiment described in detail above, the nozzle row 43 or the nozzle array 43 designed to be aligned in a predetermined direction with respect to the conveyance side edge 63 or the main scanning side edge 65 as a boundary line on the print head 24. An induced voltage generated in the ink receiving area 52 when ink droplets charged from the respective nozzles 23 forming the nozzle row 45 are sequentially ejected from the first area 52a to the second area 52b is detected, and based on the detected induced voltage. The deviation of each nozzle 23 forming the nozzle row 43 or the nozzle row 45 from the predetermined direction is grasped. The induced voltage at this time has different values with the boundary line of the first and second regions 52a and 52b as a boundary. The reason is that an induced voltage generated by electrostatic induction in the process in which the charged ink droplet reaches the first region 52a from the nozzle 23 and electrostatic induction in the process in which the charged ink droplet reaches the second region 52b from the nozzle 23. The inductive voltage generated by the difference between the electric field strength generated between the print head 24 and the first region 52a and the electric field strength generated between the print head 24 and the second region 52b are different from each other. For this reason, based on the induced voltage detected in the ink receiving area 52, the ink droplets ejected from the nozzles 23 are placed in either the first area 52a or the second area 52b across the boundary line where the nozzles 23 should be arranged. You can see if it has reached. That is, if the arrangement of the nozzles 23 is not shifted, it can be determined whether or not the ink droplet has reached the area that should be originally reached. In this way, when ejecting ink droplets, it is possible to know whether the ink droplets have reached the area that should be originally reached by design. Therefore, the ink is ejected onto the inspection sheet, and the inspection sheet after the ejection is ejected. It is possible to grasp the displacement of the nozzles 23 of the print head 24 more quickly compared to grasping the position of the ink droplets and grasping the displacement of the nozzles 23.

  In addition, since the ink receiving area 52 has a step as a boundary line by the inspection plate 60, the distance between the print head 24 and the first area 52a is different from the distance between the print head 24 and the second area 52b. Thus, the electric field strength between the print head 24 and the first region 52a and the electric field strength between the print head 24 and the second region 52b can be set to different values. Furthermore, whether or not the ink receiving area 52 is divided into the first area 52a and the second area 52b can be easily switched depending on whether or not the inspection plate 60 is disposed above the print head inspection apparatus 50. Furthermore, the ink receiving area 52 has a single straight line as a boundary line, and each nozzle forming a nozzle row 43 or a nozzle row 45 designed to be arranged in a direction parallel to the boundary line on the print head 24. Since the ink droplets charged from the nozzle 23 are sequentially ejected from the first area 52a to the second area 52b, the designed arrangement of the nozzles 23 and the boundary of the ink receiving area 52 can be easily matched. Displacement can be accurately grasped. Since the ink receiving area 52 has the conveyance side edge 63 or the main scanning side edge 65 of the inspection plate 60 arranged so as to cover a part of the ink receiving area 52 as a boundary line, the ink receiving area 52 of the inspection plate 60 By using the edge as a boundary line, the ink receiving area 52 can be easily divided into the first area 52a and the second area 52b.

  Further, the ink receiving area 52 has a conveyance-side edge 63 formed so as to be parallel to the conveyance direction as a boundary line, and ink droplets charged from each nozzle 23 forming the nozzle row 43 are transferred from the first area 52a to the second area. Since the carriage motor 34 is controlled so that the print head 24 is sequentially ejected over 52b and the print head 24 moves in the main scanning direction, the print head 24 can be moved in the main scanning direction, and the nozzles 23 are arranged with respect to the boundary line where the nozzles 23 should be arranged. 23 can be moved relatively easily in the main scanning direction. Further, by using the conveyance-side edge 63 formed so as to be parallel to the conveyance direction as a boundary line, it is possible to grasp the displacement of the arrangement of the nozzles 23 arranged in the conveyance direction with a relatively simple configuration.

  The ink receiving area 52 uses the main scanning side edge 65 formed parallel to the main scanning direction as a boundary line, and the ink droplets charged from the nozzles 23 forming the nozzle row 45 are transferred from the first area 52a to the first receiving area 52a. The nozzles 23 should be arranged because the inspection plate 60 can be moved in the transport direction in order to control the paper feed roller 35 and the like so that the inspection plate 60 is transported in the transport direction while discharging sequentially over the two regions 52b. The boundary line can be relatively easily moved in the transport direction with respect to the print head 24. Further, since the main scanning side edge 65 formed so as to be parallel to the main scanning direction is used as a boundary line, it is possible to grasp the displacement of the arrangement of the nozzles 23 arranged in the main scanning direction with a relatively simple configuration. it can.

  Further, in order to grasp the inclination of the print head 24 based on the induced voltage detected by the voltage detection circuit 54, by directly using the ink droplets ejected from the nozzle 23, the inclination of the print head 24 is grasped. It is possible to grasp the inclination of the print head 24 with higher accuracy than indirect determination of the inclination of the print head 24. In addition, since the information regarding the recognized displacement of the nozzles 23 is displayed and output on the operation panel 78, the output information regarding the displacement of the nozzles 23 can be easily used. Furthermore, since it is possible to perform the inspection whether or not the ink droplets are normally ejected from the print head 24 and the inspection of the displacement of the nozzle 23 in the same ink receiving area 52, whether or not the ink droplets are ejected normally. There is no need to newly provide a region for performing the inspection. Furthermore, when the nozzle arrangement inspection is executed, a predetermined potential difference is generated between the print head 24 and the upper ink absorber 55, and the ink droplets before being ejected from the nozzles 23 are charged. It is possible to generate electrostatic induction due to ink ejection.

  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, a step is formed in the first region 52a and the second region 52b using the first slit 62 and the second slit 64 of the inspection plate 60, but as shown in FIG. A step may be formed on the surface of the upper ink absorber 55, and the upper step surface of the step may be the first region 152a and the lower step surface of the step may be the ink receiving region 152 having the second region 152b. FIG. 13 is an explanatory diagram of another print head inspection apparatus 150. In the print head inspection apparatus 150, the voltage detection circuit 54 may be configured to detect a change in voltage across the ink receiving area 52. In the nozzle arrangement inspection routine described above, ink is sequentially ejected from the nozzles 23 from the first region 52a to the second region 52b to detect the induced voltage. Here, a threshold value V1 determined based on the maximum value of the induced voltage detected in the first region 152a and a threshold value V2 determined based on the maximum value of the dielectric voltage detected in the second region 52b are set. ing. This threshold value V1 is determined as a value that can determine that an ink droplet has been ejected to the first region 152a even if there is an influence of noise or the like. Further, the threshold value V2 is set as a value with which it is possible to determine that an ink droplet has been ejected to the second region 152b even under the influence of noise or the like. Therefore, when the detected dielectric voltage is equal to or higher than the threshold value V1, it is considered that the ink droplet ejected from the nozzle 23 has landed on the first region 152a, and the detected dielectric voltage is equal to or higher than the threshold value V2 and lower than the threshold value V1. In some cases, it is considered that the ink droplet ejected from the nozzle 23 has landed on the second region 152b. In the same manner as described above, the displacement of the nozzle 23 is grasped. Even in this case, since the distance between the print head 24 and the first region 152a and the distance between the print head 24 and the second region 152b are different from each other, the electric field strength between the print head 24 and the first region 152a is relatively simple. And the electric field strength between the print head 24 and the second region 152b can be different values. When grasping the displacement of the nozzle row 45, the ink receiving area 152 is arranged so that the boundary line is parallel to the main scanning direction, and the print head 24 can be moved in the transport direction, or the ink receiving area 152 Are configured to be movable in the transport direction and move relatively in the transport direction. Alternatively, a step may be formed in the ink receiving area 52 using an end portion (front end portion, left and right end portions, etc.) of the recording paper S (for example, thick paper) fed to the platen 44, or a print head inspection The apparatus may be provided outside the printable area (for example, in the vicinity of the flushing area 42), and a step may be formed in the ink receiving area 52 using an edge from the platen 44 to the upper ink absorber 55.

  In the above-described embodiment, the inspection plate 60 is formed of resin. However, the inspection plate 60 may be formed of a glass plate, a metal plate, paper, or the like, and can absorb ink droplets. It may be formed of a plate-like body made of any material (for example, sponge). Even in this case, the ink receiving area 52 can be easily divided into the first area 52a and the second area 52b by using the edge of the inspection plate 60 as a boundary line.

  In the embodiment described above, the information on the grasped displacement of the nozzles 23 is displayed and output on the operation panel 78, but the grasped information on the displacement of the nozzles 23 may be output to a speaker (not shown). The grasped displacement information of the nozzles 23 may be printed out to the printer mechanism 21. Even in this case, it is possible to use the output information regarding the displacement of the arrangement of the nozzles 23.

  In the above-described embodiment, the main routine including the ink discharge inspection routine and the nozzle arrangement inspection routine is executed after receiving an inspection command from the operator PC 10 at the time of inspection before shipment of the ink jet printer 20. The main routine described above may be executed after receiving an inspection command from the user PC or by operating the operation panel 78 during use. In this way, when nozzle discharge abnormality or nozzle arrangement abnormality occurs during use by the user, they can be inspected. At this time, the execution timing of the ink ejection inspection routine may be executed at a timing unrelated to the main routine described above. For example, the number of movements of the carriage 22 may be reached every time (for example, every 100 passes) or every predetermined interval (for example, every day or every week). Further, the head inspection routine may be omitted from the main routine described above.

  In the above-described embodiment, the print head 24 is moved and printed in the main scanning direction by the carriage belt 32 and the carriage motor 34. However, the print head 24 may be applied to the print head 24 that does not move in the main scanning direction. Specifically, a print head (a so-called line inkjet head, which is provided with nozzle rows of each color arranged in the main scanning direction orthogonal to the conveyance direction of the recording sheet S with a length equal to or longer than the width of the recording sheet S. For example, the invention may be applied to one that ejects ink onto the recording paper S according to Japanese Patent Application Laid-Open No. 2002-103597. At this time, the ink receiving area 52 of the print head inspection apparatus 50 is formed to have a size capable of receiving the ink ejected from the nozzle row and nozzle row of each color. Even in this way, it is possible to grasp the displacement of the arrangement of the nozzles 23 of the print head 24 more quickly.

  In the above-described embodiment, the full-color ink jet printer 20 adopting the ink jet method is used. However, a multifunction printer equipped with a scanner may be used, or a complex printing apparatus such as a FAX machine or a copier may be used.

1 is a configuration diagram illustrating an outline of a configuration of an inkjet printer 20. 2 is an explanatory diagram of a print head 24. FIG. 3 is an explanatory diagram of a paper feeding mechanism 31. FIG. 2 is a configuration diagram showing an outline of a configuration of a print head inspection apparatus 50. FIG. It is explanatory drawing of the plate for a test | inspection. It is a flowchart of a main routine. 4 is a flowchart of an ink discharge inspection routine. It is explanatory drawing of the principle which an induced voltage produces by electrostatic induction. It is a flowchart of a nozzle arrangement inspection routine. FIG. 6 is an explanatory diagram for detecting a displacement of a nozzle in a nozzle row. 6 is an explanatory diagram of processing for detecting the inclination of the print head 24. FIG. FIG. 6 is an explanatory diagram for detecting a displacement of a nozzle in a nozzle row. 4 is a configuration diagram of another print head inspection apparatus 150. FIG.

Explanation of symbols

  10 operator PC, 14 paper feed tray, 18 recording paper insertion slot, 20 ink jet printer, 21 printer mechanism, 22 carriage, 23, 23Y, M, C, K nozzle, 24 print head, 25 linear encoder, 26 ink cartridge, 28 Guide, 31 Paper feed mechanism, 32 Carriage belt, 33 Drive motor, 34 Carriage motor, 35 Paper feed roller, 36 Paper feed roller, 37 Paper discharge roller, 40 Cap device, 42 Flushing area, 43, 43Y, 43M, 43C , 43K nozzle row, 44 platen, 45 nozzle row, 47 mask circuit, 48 piezoelectric element, 50, 150 print head inspection device, 51 inspection box, 52, 152 ink receiving area, 52a, 152a first area, 52b, 152b first 2 areas, 5 Voltage application circuit, 54 Voltage detection circuit, 54a Integration circuit, 54b Inversion amplification circuit, 54c A / D conversion circuit, 55 Upper ink absorber, 56 Lower ink absorber, 57 Electrode member, 60 Inspection plate, 62 1st Slit, 63 Conveying edge, 64 Second slit, 65 Main scanning edge, 70 Controller, 72 CPU, 73 ROM, 74 RAM, 77 I / O port, 78 Operation panel, 79 Interface (I / F).

Claims (13)

A print head inspection apparatus for inspecting a print head having a plurality of nozzles for discharging a print recording liquid,
A printing recording liquid receiving area that is capable of receiving the printing recording liquid ejected from the nozzle and is divided by a predetermined boundary line into first and second areas having different electric field strengths generated between the printing head and the print head; ,
Print head driving means for discharging the printing recording liquid from the nozzle;
An electrical change detecting means for detecting an electrical change in the print recording liquid receiving area;
The print recording liquid charged from each nozzle in a nozzle row or nozzle row designed to be aligned in a predetermined direction with respect to the boundary line on the print head is sequentially discharged from the first area to the second area. An electrical change that occurs in the print recording liquid receiving area when the print head driving means is controlled is detected by the electrical change detecting means, and the nozzle row or the nozzle row is detected based on the detected electrical change. Control means for grasping a deviation from the predetermined direction of each nozzle forming
Print head inspection apparatus. The printing recording liquid receiving area has a step as the boundary line,
The print head inspection apparatus according to claim 1. The printing recording liquid receiving area has a straight line as the boundary line,
The control unit is configured to transfer the print recording liquid charged from each nozzle forming a nozzle row or nozzle row designed to be aligned in a direction parallel to the boundary line on the print head from the first region. Controlling the print head driving means to sequentially discharge over the second region;
The print head inspection apparatus according to claim 1 or 2. The printing recording liquid receiving area has, as the boundary line, an edge of a predetermined inspection plate arranged so as to cover a part of the printing recording liquid receiving area.
The print head inspection apparatus according to claim 1. The print head inspection apparatus according to claim 4,
A print head moving means capable of moving the print head in a main scanning direction substantially orthogonal to a conveyance direction of a print medium for printing an image;
The printing recording liquid receiving region has the conveyance-side edge of the inspection plate formed to be parallel to the conveyance direction as the boundary line,
The control means supplies the print recording liquid charged from each nozzle in the nozzle array designed to be aligned in a direction parallel to a boundary line by the transport side edge on the print head from the first region. Controlling the print head driving means to sequentially discharge over the second region and controlling the print head moving means to move the print head in the main scanning direction;
Print head inspection device. The print head inspection apparatus according to claim 4 or 5,
Transport means capable of transporting the inspection plate in the transport direction of a print medium for printing an image,
The printing recording liquid receiving region has the main scanning side edge of the inspection plate formed so as to be parallel to the main scanning direction in which the nozzles are arranged as the boundary line,
The control unit is configured to transfer the print recording liquid charged from each nozzle in the nozzle row designed to be arranged in a direction parallel to a boundary line by the main scanning side edge on the print head to the first region. Controlling the print head drive means to sequentially discharge from the second region to the second plate and controlling the transport means so that the inspection plate is transported in the transport direction.
Print head inspection device. The control means grasps the inclination of the print head based on the electrical change detected by the electrical change detection means;
The print head inspection apparatus according to claim 1. The print head inspection apparatus according to claim 1,
Output means for outputting information on the displacement of the nozzles grasped by the control means,
Print head inspection device. The control means includes: an electrical change detecting means for controlling the print head driving means so that the print recording liquid is discharged toward the print recording liquid receiving area for each of the plurality of nozzles of the print head. Inspecting whether or not the printing recording liquid is normally discharged from the nozzle based on the detection result,
The print head inspection apparatus according to claim 1. The print head inspection apparatus according to claim 1,
A potential difference generating means for generating a predetermined potential difference between the print head and the printing recording liquid receiving area and charging the printing recording liquid before discharging from the nozzle;
The potential difference generating means controls the print head driving means to sequentially discharge the printing recording liquid from the first area to the second area, and between the printing head and the printing recording liquid receiving area. Generating the predetermined potential difference and charging the printing recording liquid before discharging from the nozzle,
Print head inspection device. A print head comprising a plurality of nozzles for discharging the print recording liquid;
A print head inspection apparatus according to any one of claims 1 to 10,
Printing device with A print head having a plurality of nozzles for discharging a print recording liquid can receive the print recording liquid discharged from the nozzles, and first and second electric field strengths generated between the print head and the print head are different from each other. A print head inspection method for inspecting using a print recording liquid receiving area divided by a predetermined boundary line in an area,
(A) The printing recording liquid charged from each nozzle forming a nozzle row or a nozzle row designed to be arranged in a predetermined direction with respect to the boundary line on the print head from the first region to the second region. A step of sequentially discharging over,
(B) detecting an electrical change occurring in the printing recording liquid receiving area during the execution of the step (a);
(C) grasping a deviation from the predetermined direction of each nozzle forming the nozzle row or the nozzle row based on the electrical change detected in the step (b);
A print head inspection method including:   A program for causing one or more computers to execute each step of the print head inspection method according to claim 12.

Images