JP5011672B2 - Print head inspection apparatus, printing apparatus, and print head inspection method - Google Patents

Description

  The present invention relates to a print head inspection apparatus, a printing apparatus, a print head inspection method, and a program therefor, and in particular, a print head inspection apparatus, a printing apparatus, and a print head for inspecting a print head having a plurality of discharge holes for discharging a print recording liquid The present invention relates to an inspection method and a program thereof.

Conventionally, as a print head inspection device, an ink droplet ejected from a nozzle of a print head of an ink jet printer is charged, and the charged ink droplet is ejected to a portion (inspection area) that receives an ink droplet facing the nozzle. There is known a technique for inspecting whether or not an ink droplet is ejected from a nozzle by detecting an induced voltage generated by the flight of the droplet (see, for example, Patent Document 1).
JP 59-120464 A

  In this type of print head inspection apparatus, it may be possible to employ a metal plate in the inspection area. In this case, however, there is a problem that ink accumulates on the metal plate when used for a long time. To solve this problem, a liquid absorber such as a sponge is installed in the inspection area, a voltage is applied between the liquid absorber and the print head, and the charged ink droplets fly toward the liquid absorber. It is possible to make it.

  However, when the liquid absorber is made of a non-conductive material, of course, sufficient conductivity may not be obtained even if it is made of a conductive material. In such a case, the liquid absorber and the print head In some cases, the voltage applied during this period is not stabilized, and the induced voltage varies, resulting in a decrease in the inspection accuracy of the print head.

  The present invention has been made in view of such a problem, and printing that can increase the inspection accuracy of the print head by stabilizing the voltage applied between the print head and the liquid absorber in the inspection region. It is an object to provide a head inspection apparatus, a printing apparatus, a print head inspection method, and a program thereof.

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

The print head inspection apparatus of the present invention is
A print head inspection apparatus for inspecting a print head having a plurality of discharge holes for discharging a print recording liquid,
An inspection area that is made of a liquid absorber and is reachable by the print recording liquid discharged from the discharge hole;
Print head driving means for discharging the printing recording liquid from the discharge holes;
An electrical change detecting means for detecting an electrical change in the inspection area;
For each discharge hole of the print head, the print head drive unit is controlled in a state where a predetermined potential difference is generated between the inspection area and the print head and the print recording liquid before discharge is charged, and the print recording is performed. An inspection control means for performing a head inspection as to whether or not to normally discharge the print recording liquid, based on a detection result of the electrical change detection means when the liquid is discharged to the inspection area;
Prior to the head inspection by the inspection control unit, the print head driving unit is controlled so that the print recording liquid is preliminarily discharged from a predetermined discharge hole to the inspection region, so that the head inspection can be performed effectively. Preliminary discharge control means;
It is equipped with.

  In this print head inspection apparatus, for each discharge hole of the print head, a print potential is generated between the inspection region made of the liquid absorber and the print head, and the print recording liquid before discharge is charged and printed. Based on the electrical change between the inspection area and the print head when the liquid is discharged to the inspection area, a head inspection is performed to determine whether or not the print recording liquid is normally discharged. Prior to the head inspection, the printing recording liquid is preliminarily discharged from a predetermined discharge hole to the inspection area. By this preliminary discharge, the inspection area made of the liquid absorber is wetted by the print recording liquid, so that the conductivity of the liquid absorber can be ensured. As a result, when head inspection is performed, the potential difference between the print head and the inspection area is stabilized, so that the inspection accuracy of the print head is increased.

  In addition, “the head inspection can be effectively performed by preliminarily discharging the printing recording liquid from the predetermined discharge hole to the inspection region” means, for example, that the head inspection is performed only by wetting the inspection region by preliminary discharge. Can be regarded as being effective, and the print recording liquid charged during preliminary discharge is discharged to the inspection area, and the output level of the voltage between the inspection area and the print head at that time performs head inspection. It may be considered that the head inspection can be effectively performed when the level is appropriate.

  In the print head inspection apparatus according to the aspect of the invention, the preliminary ejection control unit preliminarily ejects the print recording liquid to an inspection position where the head inspection is performed at this time among a plurality of predetermined inspection positions on the liquid absorber. Also good. By doing so, the inspection position where the current head inspection is performed in the inspection area made of the liquid absorber is wetted by the printing recording liquid, so that the current head inspection can be performed with high accuracy.

  In the print head inspection apparatus of the present invention, the print recording liquid is stored separately for each color, and the preliminary discharge control unit controls the print head driving unit to perform print recording from the predetermined discharge hole. When the liquid is preliminarily discharged to the inspection area, a color printing recording liquid having a high ability to clean the liquid absorber among the printing recording liquid may be preliminarily discharged. In this way, for example, even if deposits are generated due to drying of the printing recording liquid in the inspection area, the deposits are cleaned by preliminary discharge, so that the voltage applied between the print head and the inspection area is accumulated. It is possible to eliminate the instability caused by things.

  Here, the “colored printing recording liquid having a high ability to wash the liquid absorber” includes, for example, a printing recording liquid having a low colorant content and a printing recording liquid that does not easily solidify.

  In the print head inspection apparatus according to the present invention, the preliminary ejection control unit generates a predetermined potential difference between the inspection region and the print head prior to the head inspection by the inspection control unit, thereby performing print recording before ejection. When the liquid is charged, the print head driving means is controlled to preliminarily discharge the print recording liquid from a predetermined discharge hole to the inspection area. When the preliminary discharge is performed, the electric change detection means detects the print recording liquid. The execution of the head inspection may be permitted when the extreme value of the electrical change falls within a predetermined range that is suitable for performing the head inspection in advance. In this way, it is considered that the head inspection can be effectively performed when the extreme value of the electrical change between the inspection area and the print head when pre-discharged falls within a predetermined range. There is no possibility that it is determined that the printing recording liquid is not normally ejected by mistake even though the printing recording liquid is normally ejected from the ejection hole. The preliminary discharge control means uses an average value of the extreme values of the discharge holes where the electrical change has occurred when the preliminary discharge is performed as the extreme value when there are a plurality of the predetermined discharge holes. Also good. In this way, the extreme values of the discharge holes that do not cause an electrical change when pre-discharged are excluded when calculating the average value.

  At this time, when the extreme value does not fall within the predetermined range, the preliminary discharge control unit controls the print head driving unit to perform preliminary discharge again from the predetermined discharge hole to the inspection area. Also good. In this case, after preliminary discharge is performed again, there is a high possibility that the extreme value of the electrical change falls within a predetermined range. The preliminary ejection control means may increase the amount of the printing recording liquid when performing preliminary ejection again. In this case, when the preliminary ejection is performed again, there is a higher possibility that the extreme value of the electrical change falls within the predetermined range as compared with the case where the same amount of printing recording liquid as the previous preliminary ejection is used. On the other hand, when the inspection control means determines that the extreme value falls within the predetermined range by the preliminary ejection control means when performing the head inspection, the preliminary ejection ejection holes are determined from the ejection holes. Whether or not the printing recording liquid is normally ejected may be determined based on the detection result of the electrical change detection means when the preliminary ejection is performed. In this way, it is not necessary to discharge the print recording liquid for the discharge holes that have been subjected to the preliminary discharge after the preliminary discharge, so that it is not necessary to waste the print recording liquid.

  Note that the “predetermined range” is set to a range that is necessary for accurate head inspection. For example, the absolute value of the boundary value that defines the inside and outside of the predetermined range is determined from the ejection hole when performing head inspection. You may set so that it may exceed the absolute value of the threshold value at the time of determining whether the printing recording liquid is discharging normally.

  The print head inspection apparatus of the present invention comprises a potential difference generating means for generating a predetermined potential difference between the print head and the inspection area and charging the print recording liquid before being discharged from the discharge hole, and generating the potential difference. The means may generate the predetermined potential difference between the print head and the inspection area at least when the head inspection is performed, and may charge the print recording liquid before being discharged from the discharge holes.

  A printing apparatus according to the present invention includes a print head having a plurality of ejection holes for ejecting a print recording liquid, and the print head inspection apparatus described above. As described above, the print head inspection apparatus of the present invention wets the inspection region made of the liquid absorber with the print recording liquid by pre-discharging the print recording liquid from the predetermined discharge hole to the inspection region prior to the head inspection. Since electrical conductivity can be ensured, when performing head inspection, the voltage applied between the print head and the inspection area is stabilized, and the inspection accuracy of the print head is increased. Similar effects can be obtained.

The print head inspection method of the present invention includes:
A print head inspection method for inspecting a print head having a plurality of ejection holes for ejecting a print recording liquid by using an inspection area made of a liquid absorber and reachable by the print recording liquid ejected from the ejection holes. ,
(A) For each discharge hole of the print head, the inspection is performed on the charged print recording liquid in a state where a predetermined potential difference is generated between the inspection area and the print head and the print recording liquid before discharge is charged. Performing a head inspection as to whether or not to normally discharge the printing recording liquid based on the electrical change of the inspection area when discharged to the area;
(B) prior to the head inspection in the step (a), enabling the head inspection to be performed effectively by pre-discharging the print recording liquid from a predetermined ejection hole to the inspection area;
Is included.

  In this print head inspection method, print recording is performed in a state where a predetermined potential difference is generated between the inspection area made of the liquid absorber and the print head for each ejection hole of the print head and the print recording liquid before discharge is charged. Based on the electrical change between the inspection area and the print head when the liquid is discharged to the inspection area, a head inspection is performed to determine whether or not the print recording liquid is normally discharged. Prior to the head inspection, the printing recording liquid is preliminarily discharged from a predetermined discharge hole to the inspection area. By this preliminary discharge, the inspection area made of the liquid absorber is wetted by the print recording liquid, so that the conductivity of the liquid absorber can be ensured. As a result, when head inspection is performed, the potential difference between the print head and the inspection area is stabilized, so that the inspection accuracy of the print head is increased. In this print head inspection method, steps for realizing the functions of the various print head inspection apparatuses described above may be added.

  The present invention is a program for causing one or more computers to execute 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 distributed to a plurality of computers, each step of the above-described print head inspection method is executed, so that the same effect as the above-described print head inspection method can be obtained. It is done.

  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 and FIG.

  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 near the right end of the platen 44, a print head inspection device 50 formed near the left end on the platen 44 and inspecting whether or not ink droplets are normally ejected from the print head 24, and an inkjet printer 20 and a controller 70 for controlling the entire system 20. 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 left and right along a guide 28 by a carriage belt 32 and a carriage motor 34, and mounted on the carriage 22, yellow (Y), magenta (M), cyan (C), and black (K) ink cartridges 26 that individually store inks of each color, a print head 24 that applies pressure to each ink supplied from each ink cartridge 26, and ink droplets that have been pressurized by the print head 24 are recorded on recording paper. A nozzle 23 serving as an emission hole for discharging to S and a platen 44 serving as a support member for supporting the recording paper S being printed are provided. 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.

  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. Hereinafter, description will be given using the nozzle 23K. In the print head 24, 180 nozzles 23 </ b> K are arranged along the transport 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 for specifying the nozzles included in the nozzle row. In this embodiment, since the nozzle row is composed of 180 nozzles, n is any number from 1 to 180. It becomes a numerical value. 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 an inspection box 51 in which ink droplets flying from the nozzles 23 of the print head 24 can land. An inspection area 52 provided at a predetermined distance from the print head 24, a voltage application circuit 53 for applying a voltage between the inspection area 52 and the print head 24, and a voltage of the inspection area 52 are detected. And a voltage detection circuit 54. The inspection box 51 is a housing that is provided at a position off the left side from the printable area of the platen 44 and is a substantially rectangular parallelepiped with an upper portion opened. The inspection area 52 is provided in the inspection box 51, and an upper ink absorber 55 on which ink droplets directly land, and a lower ink that absorbs ink droplets that have been transmitted downward after landing on the upper ink absorber 55. The absorber 56 and a mesh-like electrode member 57 disposed between the upper ink absorber 55 and the lower ink absorber 56 are configured. The upper ink absorber 55 is made of a conductive sponge so as to have the same potential as the electrode member 57, and the surface thereof is an inspection region 52. 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 a higher ink holding power than the upper ink absorber 55 and is made of a nonwoven fabric such as felt. Here, a nonwoven fabric (trade name: kino cloth, prince kino cloth ( Co., Ltd.) is used. 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 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, that is, the inspection region 52 is also at the same potential as the electrode member 57. The voltage detection circuit 54 is connected so as to detect the voltage of the electrode member 57 equated with the voltage of the inspection region 52, integrates and outputs the voltage signal of the electrode member 57, and the integration circuit 54a. An inverting amplification circuit 54b that inverts and amplifies the output signal and outputs the signal, and an A / D conversion circuit 54c that A / D converts the signal output from the inverting amplification circuit 54b and outputs the signal 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 since the voltage change due to the flight / landing of one ink droplet is small. 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.

  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 an inspection box 51 in which ink droplets flying from the nozzles 23 of the print head 24 can land. An inspection area 52 provided at a predetermined distance from the print head 24, a voltage application circuit 53 for applying a voltage between the inspection area 52 and the print head 24, and a voltage of the inspection area 52 are detected. And a voltage detection circuit 54. The inspection box 51 is a housing that is provided at a position off the left side from the printable area of the platen 44 and is a substantially rectangular parallelepiped with an upper portion opened. The inspection area 52 is provided in the inspection box 51, and an upper ink absorber 55 on which ink droplets directly land, and a lower ink that absorbs ink droplets that have been transmitted downward after landing on the upper ink absorber 55. The absorber 56 and a mesh-like electrode member 57 disposed between the upper ink absorber 55 and the lower ink absorber 56 are configured. The upper ink absorber 55 is made of a conductive sponge so as to have the same potential as the electrode member 57, and the surface thereof is an inspection region 52. 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 a higher ink holding power than the upper ink absorber 55 and is made of a nonwoven fabric such as felt. Here, a nonwoven fabric (trade name: kino cloth, prince kino cloth ( Co., Ltd.) is used. 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 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, that is, the inspection region 52 is also at the same potential as the electrode member 57. The voltage detection circuit 54 is connected so as to detect the voltage of the electrode member 57 equated with the voltage of the inspection region 52, integrates and outputs the voltage signal of the electrode member 57, and the integration circuit 54a. An inverting amplification circuit 54b that inverts and amplifies the output signal and outputs the signal, and an A / D conversion circuit 54c that A / D converts the signal output from the inverting amplification circuit 54b and outputs the signal 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 since the voltage change due to the flight / landing of one ink droplet is small. 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. 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, A flash memory 75 that can write and erase data, an interface (I / F) 79 that exchanges information with an external device, and an input / output port (not shown) are provided. The ROM 73 stores processing programs for a main routine, a preliminary discharge routine, a head inspection routine, and a print processing routine, which will be described later. The RAM 74 is provided with a print buffer area, and print data transmitted from the user PC 10 via the I / F 79 is stored in the print buffer. A voltage signal output from the voltage detection circuit 54 of the print head inspection apparatus 50, a position signal from the linear encoder 25, and the like are input to the controller 70 via an input port (not shown) and output from the user PC 10. The printed print job is input via the I / F 79. Further, from the controller 70, a control signal to the print head 24 (including the mask circuit 47 and the piezoelectric element 48), a control signal to the drive motor 33, a drive signal to the carriage motor 34, and an operation control signal to the cap device 40. Are output via an output port (not shown), and print status information to the user PC is output via the I / F 79.

  Next, the operation of the ink jet printer 20 of the present embodiment configured as described above will be described. Here, first, the operation of the main routine will be described with reference to FIG. FIG. 5 is a flowchart of a main routine executed by the CPU 72 of the controller 70. This routine is executed by the CPU 72 at predetermined timings (for example, every several msec) after the power of the inkjet printer 20 is turned on. When this routine is started, the CPU 72 first determines whether there is print data waiting to be printed (step S100). Here, the print data received from the user PC 10 is stored in the print buffer area formed in the RAM 74 and becomes print data waiting to be printed. Therefore, when the print data is received, it is printed immediately as well as when printing is in progress. Even if possible, the print data is in a print waiting state. If there is no print data waiting for printing in step S100, the main routine is terminated. On the other hand, if there is print data waiting for printing in step S100, a preliminary ejection routine is executed (step S110). This preliminary discharge routine is a process that is performed prior to the head inspection routine, and is a process for enabling the head inspection to be performed effectively, but will be described later because it is easier to understand after the head inspection routine. I will decide.

  After completion of the preliminary discharge routine, it is determined whether or not the permission flag F is a value 1 (step S120). The permission flag F is set to a value of 1 when it is determined in the preliminary ejection routine that the head inspection can be performed effectively, but zero when it is determined that the head inspection cannot be performed effectively. Reset to. If the permission flag F is zero in step S120, an error message is displayed on an operation panel (not shown) (step S170), and this main routine is terminated. On the other hand, when the permission flag F is 1 in step S120, the head inspection routine is started because the head inspection can be effectively performed (step S130).

  This head inspection routine is a process for inspecting whether all the nozzles 23 arranged in the print head 24 are clogged. FIG. 6 is a flowchart of this head inspection routine. When this routine is started, the CPU 72 acquires the current inspection position, that is, the position of the inspection region 52 that ejects ink from the nozzles 23 (step S300). Here, since the solid matter contained in the ink may be deposited on the surface of the inspection region 52 due to the ejection of the ink, the inspection position is set to be changed every time the head inspection is performed. FIG. 7 is an explanatory diagram of the inspection position in the print head inspection process. In FIG. 7, a plurality of inspection positions p1, p2, p3, and p4 are set. In one head inspection, each nozzle row 43 is the same so that variations in the detected value of the dielectric voltage due to the difference in inspection position do not occur. It is set to eject ink to the inspection position. For example, when this head inspection is performed at the inspection position p1, the nozzle row 43Y is first positioned so as to face the inspection position p1, and ink droplets are ejected from the nozzles 23Y included in the nozzle row 43Y. Next, the nozzle row 43M is positioned so as to face the inspection position p1, and ink droplets are ejected from the nozzles 23M included in the nozzle row 43M. Thereafter, the nozzle rows 43C and 43K are similarly tested at the inspection position p1. Ink droplets are ejected from the nozzles 23C and 23K. Further, the ink is ejected to a position different from the current inspection position at the next inspection position so that the solid content of the ink is not excessively accumulated only at a certain inspection position. For example, when the current head inspection is performed at the inspection position p1, the next head inspection is performed at the inspection position p2. Returning to FIG. 6, after acquiring the current inspection position in step S <b> 300, the CPU 72 drives the carriage motor 34 so that the nozzle array 43 to be inspected among the nozzle arrays 43 of the print head 24 is set to the current inspection position. The carriage 22 is moved so as to oppose (step S310), and the ink charged from the nozzle 23 via the mask circuit 47 and the piezoelectric element 48 (see FIG. 2) of one nozzle 23 in the nozzle row 43 to be inspected. Drops are ejected (step S320).

  Here, a change in voltage in the electrode member 57 when the charged ink droplets fly from the nozzles 23 of the print head 24 and reach the inspection region 52 including the upper ink absorber 55 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. In addition, since the print head 24 and the inspection area 52 are arranged at a distance and a predetermined potential difference is generated between them, a predetermined electric field strength (= potential difference / distance) is generated between them. Yes. 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 applied 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 (inspection region 52), but also on the presence or 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. Therefore, one segment of the first to third pulses P1, P2, representing the drive waveform. By performing the operation of outputting all of P3 eight times, ink droplets for 24 shots are ejected. 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.

  Returning to FIG. 6, the CPU 72 discharges the charged ink droplet 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 in this way. It is determined whether the amplitude of the signal output from the detection circuit 54, that is, the output level is equal to or higher than the threshold value Vthr (step S330). As shown in FIG. 9, this threshold value Vthr exceeds the output level when ink for 24 shots is normally ejected, and exceeds noise due to noise or the like when ink for 24 shots is not ejected normally. It is a value determined empirically so that nothing happens. When the output level is less than the threshold value Vthr in step S330, 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 S340). After step S340 or when the output level is equal to or higher than the threshold value Vthr in step S330 (that is, when the current nozzle 23 is normal), the CPU 72 inspects all the nozzles 23 included in the nozzle row 43 currently being inspected. If there is an uninspected nozzle 23 in the currently inspected nozzle row (step S350), the nozzle 23 to be inspected is updated to an uninspected nozzle (step S360), and then again in step S320. Perform the following processing. 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 all the nozzle rows 43 included in the print head 24 have been inspected (step S370). ) When there is an uninspected nozzle row 43, the nozzle row 43 to be inspected is updated to the uninspected nozzle row 43 (step S380), and then the processing after step S310 is performed again. On the other hand, when all the nozzle rows 43 included in the print head 24 have been inspected in step S370, this head inspection routine is ended. By executing this routine, if there is a nozzle 23 in which an abnormality has occurred among all the nozzles 23 arranged in the print head 24, information for specifying the nozzle 23 is stored in the predetermined area of the RAM 74. If there is no nozzle 23 in which an abnormality has occurred, nothing is stored.

  Now, returning to the main routine of FIG. 5, after executing the above-described head inspection routine (step S130), it is determined whether or not there is a nozzle 23 in which an abnormality has occurred among all the nozzles 23 arranged in the print head 24. Judgment is made based on the contents stored in a predetermined area of the RAM 74 (step S140), and when there is a nozzle 23 in which an abnormality has occurred, the print head 24 is cleaned in consideration of clogging. It is determined whether the number of cleanings performed before that is less than a predetermined number (for example, 3 times) (step S150). When the number of cleanings is less than the predetermined number, the print head 24 is cleaned (step S160). 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 S130 again to check whether the abnormality of the nozzle 23 has been resolved. In this step S160, only the nozzle 23 in which an abnormality has occurred may be re-inspected, but the nozzle 23 that was normal at the time of cleaning may be clogged for some reason. Re-inspect all nozzles 23. On the other hand, when the number of cleanings performed in step S150 is a predetermined number or more, it is considered that the nozzle 23 in which an abnormality has occurred is not normalized even if cleaning is performed, and an error message is displayed on an operation panel (not shown) (step S170). ) This main routine is terminated.

  On the other hand, when there is no nozzle 23 in which an abnormality has occurred in step S140, a print processing routine is executed (step S180). This print processing routine is a process for printing the print data as shown in FIG. Here, “bidirectional printing” will be described as an example. When this routine is started, the CPU 72 first executes a paper feed process (step S400). The paper feed process is a process of conveying the recording paper S placed on the paper feed tray 14 to the paper feed roller 35 by driving the drive motor 33 to rotate the paper feed roller 36 (see FIG. 4). Next, the CPU 72 drives the carriage motor 34 to eject the ink from the print head 24 while moving the carriage 22 leftward in FIG. 1 from the home position or the like, and executes forward printing based on the print data (step S410). . Subsequently, the CPU 72 determines whether or not there is print data to be printed on the recording paper S currently being printed (step S420). A conveyance process for rotating the roller 35 and conveying the recording sheet S by a predetermined amount is executed (step S430), and ink is ejected from the print head 24 while the carriage 22 is moved rightward in FIG. Return pass printing is executed based on the print data (step S440). Subsequently, the CPU 72 determines whether or not there is print data to be printed on the recording paper S currently being printed (step S450). A conveyance process for rotating the roller 35 to convey the recording paper S by a predetermined amount is executed (step S460), and the processes of steps S410 to S450 are executed. On the other hand, when there is no print data to be printed on the recording paper S that is currently being printed in step S420 or step S450, the CPU 72 executes a paper discharge process for discharging the recording paper S (step S470). The paper discharge process is a process of rotating the paper discharge roller 37 to discharge the recording paper S to the paper discharge tray. After step S470, the CPU 72 determines whether or not there is a next page to be printed (step S480). When there is a next page to be printed, the processing of steps S400 to S470 is executed to print the page. When there is no next page, this print processing routine is terminated. Also, the main routine of FIG. 5 ends after this print processing routine ends.

  Next, a preliminary discharge routine, which is the control that forms the core of the present invention, will be described. First, the significance of executing the preliminary discharge routine will be described. If a long time has passed after the previous printing in the inkjet printer 20, the upper ink absorber 55 may be in a dry state or a dry state. In that case, even if the upper ink absorber 55 is made of a conductive material, it may not have sufficient conductivity, and the upper ink absorber 55 and the electrode member 57 may not have the same potential. Then, the electric field strength generated between the inspection region 52 formed of the upper ink absorber 55 and the print head 24 is lower than the electric field strength required at the time of head inspection, and induction caused by electrostatic induction caused by the flying of ink droplets. The voltage becomes smaller than the initially planned value, and the accuracy of head inspection may be reduced. For this reason, prior to the head inspection, preliminary discharge is performed to wet the inspection region 52 formed of the upper ink absorber 55 with ink, thereby imparting sufficient conductivity to the upper ink absorber 55. In addition, when the upper ink absorber 55 is in a dry state or a dry state, solid content included in the ink may be deposited on the inspection region 52. It is preferable to wash away with ink. In that case, it is preferable to perform preliminary discharge with ink having high cleaning ability, for example, ink having the lowest colorant concentration. In this embodiment, since the colorant concentration of yellow ink is the lowest, preliminary ejection is performed with yellow ink.

  Next, the preliminary discharge routine will be described with reference to the flowchart of FIG. When this preliminary discharge routine is started, the CPU 72 acquires the current inspection position (step S200). Here, the current inspection position is the same position as the inspection position acquired in step S300 of the head inspection routine. Subsequently, the CPU 72 drives the carriage motor 34 to move the carriage 22 so that the yellow nozzle row 43Y to be subjected to preliminary ejection in the nozzle row 43 of the print head 24 faces the current inspection position ( In step S205, a value 1 is set in a preliminary ejection number counter N provided in a predetermined area of the RAM 74 (step S210). Subsequently, ink droplets charged from the nozzle 23 are ejected to the inspection region 52 via the mask circuit 47 and the piezoelectric element 48 (see FIG. 2) of one nozzle 23Y in the yellow nozzle row 43Y (step S215). The change in voltage in the inspection area 52 at that time is input from the voltage detection circuit 54, and the output level of the input voltage is stored in a predetermined area of the RAM 74 in correspondence with the number (1 to 180) of the nozzle 23Y (step S220). . Note that 24 shots of ink droplets are ejected per nozzle 23 during preliminary ejection, as in head inspection. In addition, since the change in voltage in the inspection area 52 when the charged ink droplets fly from the nozzles 23 of the print head 24 to the inspection area 52 has already been described in the actual head inspection routine, the description thereof is omitted here. . Thereafter, it is determined whether or not the output level has been measured for all the nozzles 23Y included in the yellow nozzle row 43Y to be subjected to preliminary ejection (step S225). If there is an unmeasured nozzle 23Y, the target for preliminary ejection is determined. The nozzle 23 </ b> Y is updated to an unmeasured nozzle (step S <b> 230), and then the processing from step S <b> 215 is performed again. On the other hand, when the output levels are stored in the RAM 74 for all the nozzles 23Y included in the yellow nozzle row 43Y in step S225, the average value Vav of the output levels is calculated (step S235). Here, for the nozzles 23Y that did not output a voltage at the time of preliminary ejection, the ink droplets were not ejected normally. Therefore, when the average including these is obtained, the conductivity of the upper ink absorber 55 is accurately determined. It becomes impossible to judge. For this reason, the data of these nozzles 23Y are not used when calculating the average value Vav. Subsequently, the CPU 72 determines whether or not the average value Vav falls within a predetermined range (see FIG. 9) determined in advance so as to be suitable for head inspection (step S240), and when the average value Vav falls within the predetermined range. The permission flag F is set from zero to the value 1 on the assumption that at least the current inspection position of the inspection region 52 on the upper surface of the upper ink absorber 55 is wetted with ink and sufficient conductivity is obtained. (Step S255), and this routine is finished. Here, as shown in FIG. 9, the predetermined range is set as a range exceeding the reference level Vs by setting the reference level Vs so as to be larger than the threshold value Vthr used in the head inspection routine. . On the other hand, when the average value Vav does not exceed the reference level Vs in step S245, the CPU 72 determines whether or not the preliminary ejection number N is a predetermined number (for example, three times) (step S245), and the preliminary ejection number N is the predetermined number. When the number of preliminary ejections N is not reached, the number of preliminary ejections N is incremented by 1 (step S250), and the processing after step S215 is performed again. This routine ends. That is, even if the processes of steps S215 to S240 are performed once, there is a case where the upper ink absorber 55 is not sufficiently wetted and the conductivity of the inspection region 52 may not be sufficiently obtained. Then, the process of steps S215 to S240 is performed again so that the lack of wetting of the upper ink absorber 55 is resolved. However, if the average value Vav does not fall within the predetermined range even after the processes of steps S215 to S240 are repeated a predetermined number of times, it is determined that the average value Vav does not fall within the predetermined range due to reasons other than insufficient wetting of the upper ink absorber 55. Then, the permission flag F is reset to zero, and this routine is finished.

  Here, the correspondence between the components of the present embodiment and the components of the present invention will be clarified. The inspection area 52 of this embodiment corresponds to the inspection area of the present invention, the mask circuit 47 and the piezoelectric element 48 correspond to the print head driving means, the voltage detection circuit 54 corresponds to the electrical change detection means, and the CPU 72 performs the inspection. It corresponds to control means and preliminary discharge control means. Further, the ink of this embodiment corresponds to the printing recording liquid of the present invention, the nozzle 23 corresponds to the ejection hole, and the voltage application circuit 53 corresponds to the potential difference generating means. 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, since the inspection region 52 including the upper ink absorber 55 is wetted by ink by performing the preliminary discharge routine prior to the head inspection routine, the upper ink absorber 55 Can be ensured. As a result, when performing the head inspection routine, the voltage applied between the print head 24 and the inspection area 52 is stabilized, so that the inspection accuracy of the print head 24 is increased. In the preliminary ejection routine, ink is preliminarily ejected to the inspection position in the inspection area 52 where the current head inspection is performed, so that the current head inspection can be accurately performed. Note that by performing the preliminary ejection routine prior to the head inspection routine, there is also an advantage that ink ejection is stabilized in the head inspection routine.

  Further, the ink used in the preliminary ejection is the ink having the lowest colorant concentration (here, yellow ink), and has a high ability to clean the upper ink absorber 55. Even if this occurs, the deposit is cleaned by preliminary ejection, so that the voltage applied between the print head 24 and the inspection region 52 can be prevented from becoming unstable due to the deposit.

  Further, since it is considered that the head inspection can be effectively performed when the output level of the voltage between the inspection region 52 and the print head 24 when the preliminary ejection is performed falls within a predetermined range, the nozzle is used when the head inspection is performed. 23, there is no possibility that it is determined that the ink is not normally ejected by mistake even though the ink is ejected normally. Further, since the preliminary ejection is performed again when the output level does not fall within the predetermined range, the possibility that the output level falls within the predetermined range eventually increases.

  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, in the preliminary ejection routine of FIG. 11, when the preliminary ejection number N reaches a predetermined number in step S245, the permission flag F is reset to zero in step S260 so that the head inspection routine cannot proceed. However, when the number N of preliminary ejections reaches the predetermined number in step S245, the print head 24 may be cleaned and the preliminary ejection may be performed again. At this time, if the number of times cleaning is performed reaches a predetermined number, the permission flag F may be reset to zero and the preliminary ejection routine may be terminated.

  In the above-described embodiment, when the average value Vav does not fall within the predetermined range in step S240 in the preliminary discharge routine of FIG. 11, the discharge amount of the next preliminary discharge is increased by a certain amount compared to the previous time. Alternatively, the discharge amount of the next preliminary discharge may be increased according to the difference between the reference level Vs (see FIG. 9) and the average value Vav. In this way, the average value Vav exceeds the reference level Vs with a small number of preliminary ejections.

  Furthermore, in the above-described embodiment, the head inspection routine shown in FIG. 6 is adopted, but instead, the head inspection routine shown in FIG. 12 may be adopted. Here, among the steps of the head inspection routine of FIG. 12, the same steps as those of the head inspection routine of FIG. 6 are denoted by the same step numbers, and description thereof is omitted. In the head inspection routine of FIG. 12, the CPU 72 acquires the current inspection position in step S300, moves the carriage 22 so that the nozzle row 43 to be inspected faces the current inspection position in step S310, and then inspects the inspection target. It is determined whether or not the nozzle row 43 to be the nozzle row 43Y that has undergone preliminary ejection (step S311), and when the nozzle row 43 to be inspected is not the nozzle row 43Y that has undergone preliminary ejection, step S320 described above is performed. After steps S360 to S360, steps S370 and S380 are performed. On the other hand, when the nozzle row 43 to be inspected is the nozzle row 43Y that has performed preliminary ejection, the output level of each nozzle 23Y of the nozzle row 43Y has already been stored in the RAM 74 in step S220 of the preliminary ejection routine. Without discharging ink from each nozzle 23Y, the output level of the nozzle 23Y to be inspected is read from the RAM 74 (step S312), and it is determined whether or not the output level is equal to or higher than a threshold value Vthr (step S313). When the output level is less than the threshold value Vthr, it is considered that an abnormality such as clogging has occurred in the current nozzle 23Y, and information for specifying the nozzle 23Y is stored in a predetermined area of the RAM 74 (step S314). After step S314 or when the output level is equal to or higher than the threshold value Vthr in step S313 (that is, when the current nozzle 23Y is normal), the CPU 72 inspects all the nozzles 23Y included in the nozzle row 43Y currently being inspected. If there is an uninspected nozzle 23Y in the nozzle row 43Y currently being inspected (step S315), the nozzle 23Y to be inspected is updated to an uninspected nozzle (step S316), and then step again The process after S312 is performed. On the other hand, when all the nozzles 23Y included in the nozzle row 43Y currently inspected are inspected in step S315, the processes in steps S370 and 380 described above are performed. As described above, for each nozzle 23Y of the nozzle row 43Y, the output level is already stored in the RAM 74 in the preliminary ejection routine executed prior to the head inspection routine. Since there is no need to measure, it is not necessary to waste ink.

  Furthermore, in the above-described embodiment, the main routine shown in FIG. 5 is adopted, but instead, the main routine shown in FIG. 13 may be adopted. Here, among the steps of the main routine of FIG. 13, the same steps as those of the main routine of FIG. 5 are denoted by the same step numbers, and the description thereof is omitted. In the main routine of FIG. 13, when there is data waiting for printing in step S100, the CPU 72 determines whether or not the interval time calculated from the end of the previous head inspection exceeds a predetermined time Ts (step S102). When the time exceeds the predetermined time Ts, processing after the preliminary discharge routine (step S110) is performed, and when the interval time does not exceed the predetermined time Ts, the preliminary discharge routine is skipped and the head inspection routine (step S130) is performed. It may be. Here, the predetermined time Ts is a value obtained empirically by examining the relationship between the elapsed time from the end of the previous head inspection and the wetting of the inspection position by an experiment or the like. That is, after the head inspection routine is executed, ink droplets are ejected from the nozzles 23 of all the nozzle rows 43 to the same inspection position, so that the inspection position adjacent thereto is often sufficiently wet with ink. . For this reason, if not much time has passed since the end of the previous head inspection, the current inspection position is also considered to be sufficiently wet, and there is no problem even if the head inspection routine is advanced without performing the preliminary ejection routine. The predetermined time Ts is determined based on such a viewpoint.

  In the above-described embodiment, the preliminary discharge routine shown in FIG. 11 is adopted. Instead, the preliminary discharge routine shown in FIG. 14 may be adopted. Here, among the steps of the preliminary discharge routine of FIG. 14, the same steps as those of the main routine of FIG. 5 are denoted by the same step numbers, and the description thereof is omitted. In the preliminary ejection routine of FIG. 14, the CPU 72 acquires the current inspection position in step S200, moves the carriage 22 so that the nozzle row 43Y to be preliminary ejected faces the inspection position in step S205, and then proceeds to step S215. In step S216, it is determined whether ink has been ejected from the nozzles 23Y of the nozzle array 43Y that are to be preliminarily ejected, and then ink has been ejected from all the nozzles 23Y in the nozzle array 43Y. When there is no nozzle 23Y, the nozzle 23Y to be subjected to preliminary ejection is updated to one that has not yet been ejected (step S217), and then the processing after step S215 is performed again. On the other hand, when ink is ejected from all the nozzles 23Y included in the yellow nozzle row 43Y in step S216, the permission flag F is set to 1 in step S255, and this routine is ended. In this preliminary discharge routine, by performing preliminary discharge from all the nozzles 23Y of the nozzle row 43Y that is the target of preliminary discharge, the current inspection position in the inspection region 52 can be wet with ink and the head inspection can be performed effectively. And the permission flag F is set to a value of 1.

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 a flowchart of a main routine. It is a flowchart of a head inspection routine. It is explanatory drawing of the test | inspection position in a head test | inspection process. It is explanatory drawing of the principle which an induced voltage produces by electrostatic induction. It is explanatory drawing which shows an example of the threshold value Vthr and the reference level Vs. It is a flowchart of a printing process routine. It is a flowchart of a preliminary discharge routine. 10 is a flowchart of another head inspection routine. It is a flowchart of another main routine. It is a flowchart of another preliminary discharge routine.

Explanation of symbols

14 Paper feed tray, 18 Recording paper insertion slot, 20 Inkjet printer, 21 Printer mechanism, 22 Carriage, 23, 23Y, 23M, 23C, 23K 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, 43, 43Y, 43M, 43C, 43K Nozzle array, 44 Platen, 47 mask circuit, 48 piezoelectric element, 50 print head inspection device, 51 inspection box, 52 inspection region, 53 voltage application circuit, 54 voltage detection circuit, 54a integration circuit, 54b inversion amplification circuit, 54c conversion circuit, 55 upper ink absorber 56 lower Ink absorber, 57 electrode member, 70 controller, 72 CPU, 73 ROM, 74 RAM, 75 flash memory, 79 interface (I / F).

Claims (12)

A print head inspection apparatus for inspecting a print head having a plurality of discharge holes for discharging a print recording liquid,
An inspection area that is made of a liquid absorber and is reachable by the print recording liquid discharged from the discharge hole;
Print head driving means for discharging the printing recording liquid from the discharge holes;
An electrical change detecting means for detecting an electrical change in the inspection area;
For each discharge hole of the print head, the print head drive unit is controlled in a state where a predetermined potential difference is generated between the inspection area and the print head and the print recording liquid before discharge is charged, and the print recording is performed. An inspection control means for performing a head inspection as to whether or not to normally discharge the print recording liquid, based on a detection result of the electrical change detection means when the liquid is discharged to the inspection area;
Prior to the head inspection by the inspection control unit, the print head driving unit is controlled so that the print recording liquid is preliminarily discharged from a predetermined discharge hole to the inspection region, so that the head inspection can be performed effectively. Preliminary discharge control means;
With
The printing recording liquid is stored separately for each color,
The preliminary ejection control unit controls the print head driving unit to preliminarily eject the print recording liquid from the predetermined ejection hole to the inspection area, and print recording of a color having a low colorant concentration in the print recording liquid. Pre-discharge liquid,
Print head inspection device. Prior to the head inspection by the inspection control unit, the preliminary ejection control unit generates a predetermined potential difference between the inspection area and the print head and charges the print recording liquid before ejection. The head drive means is controlled to preliminarily discharge the print recording liquid from the predetermined discharge hole to the inspection area, and the extreme value of the electrical change detected by the electrical change detecting means when the preliminary discharge is performed is previously set in advance. Permitting the execution of the head inspection when entering a predetermined range suitable for head inspection;
The print head inspection apparatus according to claim 1. A print head inspection apparatus for inspecting a print head having a plurality of discharge holes for discharging a print recording liquid,
An inspection area that is made of a liquid absorber and is reachable by the print recording liquid discharged from the discharge hole;
Print head driving means for discharging the printing recording liquid from the discharge holes;
An electrical change detecting means for detecting an electrical change in the inspection area;
For each discharge hole of the print head, the print head drive unit is controlled in a state where a predetermined potential difference is generated between the inspection area and the print head and the print recording liquid before discharge is charged, and the print recording is performed. An inspection control means for performing a head inspection as to whether or not to normally discharge the print recording liquid, based on a detection result of the electrical change detection means when the liquid is discharged to the inspection area;
Prior to the head inspection by the inspection control unit, the print head driving unit is controlled so that the print recording liquid is preliminarily discharged from a predetermined discharge hole to the inspection region, so that the head inspection can be performed effectively. Preliminary discharge control means;
With
Prior to the head inspection by the inspection control unit, the preliminary ejection control unit generates a predetermined potential difference between the inspection area and the print head and charges the print recording liquid before ejection. The head drive means is controlled to preliminarily discharge the print recording liquid from the predetermined discharge hole to the inspection area, and the extreme value of the electrical change detected by the electrical change detecting means when the preliminary discharge is performed is previously set in advance. Permitting the execution of the head inspection when entering a predetermined range suitable for head inspection;
Print head inspection device. The preliminary discharge control means uses an average value of the extreme values of the discharge holes in which the electrical change has occurred when the preliminary discharge is performed as the extreme value when there are a plurality of the predetermined discharge holes.
The print head inspection apparatus according to claim 2 or 3. The preliminary ejection control means, when the extreme value does not fall within the predetermined range, controls the print head driving means to preliminarily eject the printing recording liquid from the predetermined ejection hole to the inspection area;
The print head inspection apparatus according to claim 2. The preliminary ejection control means increases the amount of the printing recording liquid when preliminarily ejecting again.
The print head inspection apparatus according to claim 5. When performing the head inspection, the inspection control unit determines that the preliminary discharge control unit determines that the extreme value falls within the predetermined range. Determining whether or not to normally eject the printing recording liquid based on the detection result of the electrical change detection means when
The print head inspection apparatus according to claim 2. The preliminary ejection control means preliminarily ejects the printing recording liquid to an inspection position where a head inspection is performed this time among a plurality of predetermined inspection positions on the liquid absorber.
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 inspection area and charging the print recording liquid before being discharged from the discharge hole;
With
The potential difference generation means generates the predetermined potential difference between the print head and the inspection area at least when performing the head inspection, and charges the print recording liquid before being discharged from the discharge holes.
Print head inspection device. A print head having a plurality of discharge holes for discharging a print recording liquid;
A print head inspection apparatus according to any one of claims 1 to 9,
Printing device with A print head inspection method for inspecting a print head having a plurality of ejection holes for ejecting a print recording liquid by using an inspection area made of a liquid absorber and reachable by the print recording liquid ejected from the ejection holes. ,
(A) For each discharge hole of the print head, the inspection is performed on the charged print recording liquid in a state where a predetermined potential difference is generated between the inspection area and the print head and the print recording liquid before discharge is charged. Performing a head inspection as to whether or not to normally discharge the printing recording liquid based on the electrical change of the inspection area when discharged to the area;
(B) prior to the head inspection in the step (a), enabling the head inspection to be performed effectively by pre-discharging the print recording liquid from a predetermined ejection hole to the inspection area;
Including
The printing recording liquid is stored separately for each color,
In the step (b), when the print recording liquid is preliminarily discharged from the predetermined discharge hole to the inspection area, the print recording liquid having a low colorant concentration in the print recording liquid is preliminarily discharged.
Print head inspection method. A print head inspection method for inspecting a print head having a plurality of ejection holes for ejecting a print recording liquid by using an inspection area made of a liquid absorber and reachable by the print recording liquid ejected from the ejection holes. ,
(A) For each discharge hole of the print head, the inspection is performed on the charged print recording liquid in a state where a predetermined potential difference is generated between the inspection area and the print head and the print recording liquid before discharge is charged. Performing a head inspection as to whether or not to normally discharge the printing recording liquid based on the electrical change of the inspection area when discharged to the area;
(B) prior to the head inspection in the step (a), enabling the head inspection to be performed effectively by pre-discharging the print recording liquid from a predetermined ejection hole to the inspection area;
Including
In the step (b), prior to the head inspection, the print head driving unit is controlled in a state where a predetermined potential difference is generated between the inspection region and the print head and the print recording liquid before discharge is charged. Then, the printing recording liquid is preliminarily ejected from the predetermined ejection hole to the inspection area, and the extreme value of the electrical change detected by the electrical change detecting means when the preliminary ejection is preliminarily performed performs the head inspection in advance. Permitting execution of the head inspection when entering a predetermined range determined to be suitable for
Print head inspection method.

Images