JP2006297772A - Liquid delivery apparatus and method for delivering liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid delivery apparatus and a delivery method of liquid which enable the presence or absence of liquid-mixture of nozzles with different solution to be certainly detected in direct by detecting the presence or absence, positions and kind of the liquid which has been adhered to the faces a simple composition while enabling the operation of retrieving, wiping, changing of nozzle and coping with another liquid-mixture to be suitably performed based on the information. <P>SOLUTION: The liquid delivery apparatus comprises a recording head for holding liquid-mixture distinction materials which are different for every liquid of two or more kinds, a retrieval means for retrieving the recording head, an observation means for observing the recording head from the face side, and a liquid-mixture distinction means for judging whether the liquids of individual nozzles in the recording head are mixed. In addition, the method for delivering liquid is provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid ejecting apparatus and a liquid ejecting method for performing recording by ejecting a liquid from a recording unit to a recording object.

  Further, the present invention relates to a liquid discharge apparatus and a discharge state detection method for a liquid discharge head, and more particularly to a technique for detecting a discharge failure of a liquid discharge head and detecting a liquid adhering to a surface on which a discharge nozzle of the liquid discharge head is formed.

  Recording devices with functions such as printers, copiers, facsimiles, etc., or recording devices used as output devices such as composite electronic devices including computers and word processors and workstations, paper, cloth, plastic sheets based on recorded information An image (including characters and symbols) is recorded on a recording material (recording medium) such as an OHP sheet. The recording apparatus can be classified into an ink jet type, a wire dot type, a thermal type, a laser beam type, and the like according to a recording method.

  In a serial type recording apparatus that performs recording while performing main scanning in a direction crossing the conveyance direction (paper feeding direction, sub-scanning direction) of a recording material, recording means (on a carriage that moves along the recording material) An image is recorded (main scanning) by a recording head), and after recording for one line is completed, a predetermined amount of paper is fed (pitch conveyance as sub-scanning), and then the recording material stopped again is next Recording of the entire recording material is performed by repeating the operation of recording (main scanning) the image of the first row. On the other hand, in a line type recording apparatus that records only by sub-scanning in the conveyance direction of the recording material, the recording material is set at a predetermined recording position, and after recording for one line at a time, a predetermined amount The entire recording material is recorded by repeating the operation of performing the paper feeding (pitch feeding) and recording the next line all at once.

  Among them, an ink jet recording apparatus (ink jet recording apparatus) performs recording by ejecting ink from a recording means (recording head) to a recording material, and the recording means can be easily made compact and has high definition. Images can be recorded at high speed, can be recorded without requiring special processing on plain paper, running costs are low, non-impact method is low noise, and many types of ink (for example, For example, it is easy to record a color image using a color ink. In particular, a line-type recording apparatus using a line-type recording unit in which a large number of ejection openings are arranged in the paper width direction can further increase the recording speed.

  As an energy generating element that generates energy used for discharging ink from the discharge port of an ink jet recording head, an element that uses an electromechanical transducer such as a piezo element, or an electromagnetic wave such as a laser is irradiated to generate heat. There are those that eject ink droplets by a heat generating action, and those that heat a liquid by an electrothermal converter having a heating resistor. Among them, an ink jet recording means (recording head) that discharges ink as droplets using thermal energy can perform high-resolution recording because the discharge ports can be arranged at high density.

  In particular, an ink jet recording means (recording head) that discharges ink using thermal energy is subjected to a semiconductor manufacturing process such as etching, vapor deposition, sputtering, and the like, an electrothermal transducer, an electrode, By forming the liquid channel wall, the top plate, etc., it is possible to easily manufacture a device having a high density liquid channel arrangement (discharge port arrangement), and to achieve further compactness. In addition, by utilizing the advantages of IC technology and micro processing technology, it is easy to make the recording means longer and planarized (two-dimensional), and it is also easy to make the recording means full-multiple and high-density mounting. is there.

  In addition, there are various requirements for the material of the recording material, and in recent years, development for these requirements has progressed, and paper (including thin paper and processed paper), which is a normal recording material, and resin thin plate (OHP, etc.) In addition to the above, a recording apparatus using cloth, leather, non-woven fabric, metal, or the like as a recording material is also used.

In general, a serial type ink jet recording apparatus includes a recording unit (recording head) for performing recording, a carriage mounted with the recording unit and moving (main scanning), a driving system for the carriage, and a carrier for holding and transporting a recording material. A platen and a conveyance (paper feed) system; and an ejection recovery processing system for maintaining and recovering the ink ejection performance of the recording unit.
JP 2000-085148 A

  Non-impact printing is an inkjet printing system that discharges liquid from a discharge nozzle and prints on a print medium such as paper, cloth, plastic sheet, or OHP sheet (hereinafter also simply referred to as “recording paper”). This is one type of printing apparatus, and can perform high-density and high-speed printing operations with low noise. The ink jet printing method is an extremely excellent printing method having a simple configuration, but there are also problems to be solved.

  That is, since an ink jet printing apparatus directly discharges liquid from a fine discharge nozzle onto a print medium to form an image, the surface on which the discharge nozzle of the print head is provided (hereinafter referred to as a discharge nozzle surface or a face surface). When wet with liquid, ejection failure may occur. There are mainly two causes of the wetting. One is that the liquid ejected for printing hits the print medium, a part of which rebounds without adhering to the print medium, or a fine liquid in addition to the main liquid involved in printing when the liquid is ejected Drops may be ejected and drift in the atmosphere, but this occurs when these liquids adhere to the ejection nozzle surface.

  The other is related to the process of releasing the cap after sucking the liquid in the nozzle with the cap on the discharge nozzle surface as a recovery operation to prevent clogging of the discharge nozzle or to eliminate clogging However, liquid droplets remain on the discharge nozzle surface during the process. This is because the liquid is filled in the cap by performing the suction operation, and if the cap is removed from the discharge nozzle surface in that state, the liquid that has been in contact with the discharge nozzle surface remains on the discharge nozzle surface. Because. In order to prevent this, liquid repellent treatment may be applied to the discharge nozzle surface, but it is still difficult to completely eliminate the liquid residue.

  In addition, in order to extract the liquid remaining in the cap when the cap is separated from the discharge nozzle surface after the suction operation from the discharge nozzle, a thin plate-like absorber made of porous resin or nonwoven fabric is put in the cap. The device is put on. If there is no absorber, when the suction operation is performed with the cap opened to exclude the liquid in the cap, only the liquid immediately adjacent to the discharge nozzle in the cap is sucked and the surrounding liquid remains. That is, if the absorber is provided, the negative pressure acts gently, and the liquid in the cap is sucked out evenly.

  If unnecessary liquid droplets adhere to the vicinity of the discharge nozzle, it may cause a discharge failure such as so-called `` flipping '' in which the liquid discharge direction deviates from the normal direction or `` non-discharge '' that makes it impossible to discharge, which may cause deterioration in print quality. Become. This is because, particularly when an inkjet printing apparatus such as a textile printing apparatus or a printing apparatus is used for industrial purposes, strict quality control is required. Therefore, such a deterioration in print quality is an important problem related to the reliability of the apparatus. Become.

  As a means for solving such a problem, a method of wiping the discharge nozzle surface with a blade (or also called a wiper) as a wiping member made of an elastic member such as rubber (hereinafter also referred to as wiping or wiping) is often adopted. . Wiping methods include wiping the discharge nozzle surface by scanning the print head against a stationary blade, or letting the blade translate or rotate while the print head is stationary to discharge nozzle surface There are things that come into contact with.

  In addition, when the liquid is colored using a plurality of liquid colors such as Y, M, C, and K (yellow, magenta, cyan, and black), the other discharge nozzles that are responsible for discharging each liquid by the recovery operation are used. Liquid color may be mixed. When the mixing occurs, a color mixing phenomenon occurs and a normal color image cannot be formed.

  Conventionally, mixed liquid detection as described above is to detect the presence or absence of mixed liquid by observing the state of the printed material after printing the liquid on the printed material such as paper. Was in vain. In addition, as a method for detecting a mixed liquid without printing on the printing material, a method for detecting the mixed liquid by installing the light emitting element and the light receiving element so as to cross the flow paths of the respective nozzles (for example, see Patent Document 1), In this case, the ejection head incorporating the detection system is very complicated, and there are many problems to be solved in manufacturing. Furthermore, in a mode in which a DNA probe is ejected onto a substrate using an ink jet method as in the DNA chip manufacturing apparatus described in Japanese Patent Application No. 2003-348127, each dot has a very important meaning for determination of a specimen. Therefore, the mixed liquid phenomenon may become a fatal problem. Therefore, it is required to eliminate the mixed liquid phenomenon with certainty.

  Furthermore, if a large amount of unnecessary liquid is consumed in detecting a mixed liquid, the liquid in the liquid supply container is wasted. Then, the liquid that should be used to form the image that is the original purpose of the ink jet recording apparatus is wasted.

  The present invention has been made in view of such technical problems, and an object of the present invention is to detect the presence, position, or type of liquid adhering to the face surface with a simple configuration and to have different solutions. Provided is a liquid ejecting apparatus and a liquid ejecting method according to an ink jet recording apparatus that can directly and reliably detect the presence or absence of liquid mixture between each other and can appropriately perform recovery operation, wipe operation, nozzle replacement operation, and other mixed liquid correspondence based on the information It is to be.

  In order to achieve the above object, the present invention provides the following liquid ejection apparatus and liquid ejection method.

  (1) In a liquid ejection apparatus that ejects a plurality of types of liquid to perform recording on a recording medium, a recording head that holds a different mixed liquid discrimination substance for each of the plurality of types of liquid, and recovery for recovering the recording head Means, observation means for observing the recording head from the face side, and processing of the observed image to detect the liquid state of the face surface, and whether the liquid in each nozzle in the recording head is mixed And a liquid mixture determining means for determining whether or not.

  (2) The liquid discharge according to (1), further comprising discharge nozzle control means for determining whether or not to discharge each nozzle in the recording head based on information from the liquid mixture determination means. apparatus.

  (3) The liquid ejecting apparatus according to (1), further comprising a recovery control unit that determines whether to operate the recovery unit based on information from the mixed liquid determination unit.

  (4) It has a wiping means for wiping the recording head, and has a wiping control means for determining whether or not to operate the wiping means based on information from the mixed liquid discrimination means. The liquid ejection apparatus according to (1).

  (5) The liquid state of the face surface is at least one state of the presence / absence of liquid adhering to the face surface, the position of the liquid, and the type of liquid. apparatus.

  (6) The liquid ejection apparatus according to (1), wherein the mixed liquid discrimination substance is a pigment.

  (7) The liquid ejection apparatus according to (1), wherein the mixed liquid discrimination substance is a fluorescent dye.

  (8) The liquid ejecting apparatus according to (1), wherein the observation unit includes a CCD sensor and optically detects the liquid adhering to the face surface.

  (9) The observation means includes a laser light source and a light receiving sensor, and detects the liquid adhering to the face surface from a change in received light intensity of a laser beam passing through the liquid adhering to the face surface. The liquid ejection apparatus according to (1).

  (10) The liquid ejection apparatus according to (6), wherein the mixed liquid discrimination unit discriminates a mixed liquid by determining a difference in pigment by image processing based on information from the observation unit.

  (11) The liquid discharge apparatus according to (7), wherein the liquid mixture determination unit determines a liquid mixture by determining a difference in fluorescent dye by image processing based on information from the observation unit. .

  (12) Nozzle replacement control having nozzle replacement means for replacing the nozzles in the recording head, and determining whether to operate the nozzle replacement means based on information from the mixed liquid discrimination means The liquid ejecting apparatus according to (1), further comprising: means.

  (13) If the information from the mixed liquid determination means is a determination result that mixed liquid has occurred for the nozzle that was scheduled to be discharged, a discharge nozzle control means that prohibits discharge from the nozzle. The liquid ejecting apparatus according to (2), further comprising:

  (14) If the information from the mixed liquid determining means is a determination result that mixed liquid has occurred for the nozzle that was scheduled to be discharged, suction or pressure recovery is performed on the nozzle. The liquid ejecting apparatus according to (3), further including a recovery control unit.

  (15) If the information from the mixed liquid determination means is a determination result that mixed liquid has occurred for the nozzle that was scheduled to be discharged, wipe control means for performing a wiping operation on the nozzle The liquid ejecting apparatus according to (4), further comprising:

  (16) If the mixed liquid cannot be avoided by the liquid mixture discrimination based on the information from the liquid mixed determining means and the recovery operation by the recovery control means, is the other nozzle in the recording head replaced? The liquid ejecting apparatus according to (12), further comprising a nozzle replacement control unit that determines whether or not.

  (17) The liquid ejection apparatus according to (1), wherein the mixed liquid discrimination unit performs discrimination of the mixed liquid after the recovery unit of the recording head.

  (18) The liquid ejection apparatus according to (1), wherein after the wiping unit of the recording head, the mixed liquid discrimination unit performs discrimination of the mixed liquid.

  (19) The liquid ejection apparatus according to (1), wherein the mixed liquid discrimination unit performs discrimination of the liquid mixture before the ejection operation of the recording head.

  (20) The liquid ejecting apparatus according to (1), wherein the mixed liquid discriminating unit determines the mixed liquid after the discharge operation of the recording head.

  (21) The liquid ejection apparatus according to (1), wherein the liquid mixture is discriminated by the liquid mixture discrimination unit after the recording head supplies the liquid.

  (22) The liquid ejection according to (1), wherein the recording head is a bubble jet (registered trademark) type head including an electrothermal transducer that generates thermal energy and causes film boiling. apparatus.

  (23) The liquid ejecting apparatus according to (1), wherein the recording head is a head of a system in which a pressure is applied to a liquid chamber in a nozzle by a piezo element to eject a liquid droplet.

  (24) In a liquid ejection method for ejecting a plurality of types of liquid to perform recording on a recording medium, a step of observing a recording head that holds a different mixed liquid discrimination substance for each of the plurality of types of liquid, and an observed image And a step of detecting the state of the liquid on the face surface by processing and determining whether or not the liquid of each nozzle in the recording head is mixed.

  (25) The liquid discharge method according to (24), further including a step of determining whether or not to discharge each nozzle in the recording head based on information from the mixed liquid discrimination step.

  (26) The liquid ejection method according to (24), further including a step of determining whether or not to operate the recovery step based on information from the mixed liquid discrimination step.

  (27) The liquid ejection method according to (24), further including a step of determining whether or not to operate the wiping step based on information from the mixed liquid discrimination step.

  (28) The liquid state on the face surface is at least one state of the presence / absence of liquid adhering to the face surface, the position of the liquid, and the type of liquid, and the liquid ejection according to (24) Method.

  (29) The liquid discharge method according to (24), wherein the mixed liquid discrimination substance is a pigment.

  (30) The liquid ejection method according to (24), wherein the mixed liquid discrimination substance is a fluorescent dye.

  (31) The liquid ejecting method according to (24), wherein the observing step includes a step of optically detecting liquid adhering to the face surface, which includes a CCD sensor.

  (32) The observation step includes a step of detecting the liquid adhering to the face surface from a change in received light intensity of a laser beam which is composed of a laser light source and a light receiving sensor and transmits the liquid adhering to the face surface. (24) The liquid discharging method according to (24).

  (33) The liquid according to (24), wherein the mixed liquid discrimination step includes a step of discriminating a mixed liquid by determining a difference in pigment by image processing based on information from the observation step. Discharge method.

  (34) The mixed liquid discrimination step includes a step of discriminating a mixed liquid by determining a difference in fluorescent dye by image processing based on information from the observation step. Liquid ejection method.

  (35) The liquid ejection method according to (24), further including a step of determining whether or not to operate the nozzle replacement step based on information from the mixed liquid discrimination step.

  (36) If the information from the mixed liquid determining step is a determination result that mixed liquid has occurred for the nozzle that was scheduled to be discharged, a step of prohibiting discharge from the nozzle is included. The liquid discharging method according to (25), characterized in that it is characterized in that

  (37) If the information from the mixed liquid determining step is a determination result that mixed liquid has occurred for a nozzle that is scheduled to be discharged, suction or pressure recovery is performed on the nozzle. The liquid ejection method according to (26), further comprising a step.

  (38) If the information from the mixed liquid determining step is a determination result that mixed liquid has occurred for the nozzle that was scheduled to be ejected, a step of performing a wiping operation on the nozzle is included. The liquid ejection method as described in (27) above.

  (39) Whether the mixed liquid cannot be avoided even by the recovery operation of the recovery control process, and the other nozzles in the recording head are replaced. The liquid discharging method according to (35), further comprising a step of determining whether or not.

  (40) The liquid ejection method according to (24), wherein the mixed liquid is discriminated by the mixed liquid discriminating step after the recovery step of the recording head.

  (41) The liquid ejection method according to (24), wherein the mixed liquid is determined by the mixed liquid determining step after the wiping step of the recording head.

  (42) The liquid discharge method according to (24), wherein the mixed liquid is determined by the mixed liquid determination step before the discharge operation of the recording head.

  (43) The liquid discharge method according to (24), wherein after the discharge operation of the recording head, the mixed liquid is determined by the mixed liquid determination step.

  (44) The liquid ejection method according to (24), wherein after the liquid is supplied from the recording head, the mixed liquid is discriminated in the mixed liquid discrimination step.

  (45) The liquid ejection according to (24), wherein the recording head is a bubble jet (registered trademark) type head provided with an electrothermal transducer that generates thermal energy and causes film boiling. Method.

  (46) The liquid ejecting method according to (24), wherein the recording head is a head of a system in which a pressure is applied to a liquid chamber in a nozzle with a piezo element and a liquid droplet is ejected for recording.

  According to the present invention, it is possible to reliably prevent discharge from the liquid mixture nozzle without waste of the recording material and the discharge liquid with a simple configuration, and to appropriately perform the recovery operation, the discharge operation, and other liquid mixture correspondences. It became so.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings. In addition, although embodiment shown below is an example of the best embodiment of this invention, this invention is not limited by these embodiment.

  FIG. 1 is an overall perspective view of the ink jet recording apparatus according to the first embodiment of the present invention.

  A Y-axis stage 53 and guide rails 57 and 58 are fixed in parallel on the surface plate 59. An X-axis stage 54 is attached to the movable parts of the Y-axis stage 53 and the guide rails 57 and 58, and the X-axis stage 54 is movable in the Y direction. A chuck θ stage 55 is fixed to the movable part of the X-axis stage 54, and a chuck 56 is fixed to the upper surface of the chuck θ stage 55. The chuck 56 is connected to a pump (not shown) by a tube, and the recording member 68 is adsorbed to the chuck 56 when the pump sucks air. An observation means 14 is attached to the chuck 56 so that the entire face surface of the recording head 0 can be imaged.

  In addition, columns 65 and 66 are fixed on the surface plate 59, and bridges 63 and 64 are fixed to the columns 65 and 66, respectively. The bridges 63 and 64 are fixed by a stay 62, and the strength of the structures of the support columns 65 and 66 and the bridges 63 and 64 is maintained. Further, the head θ stage 61 is fixed between the bridges 63 and 64, and the head 0 is fixed to the head θ stage 61. A recovery unit (not shown) and a wipe unit (not shown) for cleaning the recording head 0 are also provided.

  FIG. 2 shows the recording head 0 as seen from the face side, and the nozzles 1 are arranged in a matrix. Each of these nozzles has an independent flow path, and has an opening so that the discharge liquid can be supplied from the back side of the paper surface by a pipetter or a dispensing device.

  3A and 3B are detailed views of the vicinity of the nozzle 1, FIG. 3A is a view seen from the face surface side, and FIG. 3B is a cross-sectional view taken along line AA of FIG. 2 is a nozzle port, 3 is a heater board, and 4 is an orifice plate. The discharged liquid is supplied into the nozzle 1 from the ink supply hole 5.

  FIG. 4 shows the state of the liquid adhering to the orifice surface. (A) is a contraction view of the recording head 0 shown in FIG. 2 as viewed from the face side, and (b) shows a state of the face surface in which a part of (a) is enlarged. 6 in (b) indicates a nozzle opening, and 7 indicates a liquid adhering to the face surface. The size of the liquid indicates that there are various sizes. In the present invention, the mixed liquid discrimination means can detect the presence, position, and type of these liquids that cause the mixed liquid phenomenon by performing image processing.

  FIG. 5 is a control block diagram of the ink jet recording apparatus in the present embodiment.

  The entire apparatus is controlled by the CPU 10 serving as a control unit executing a program stored in the memory 11. The CPU 10 detects the liquid adhering to the face surface, controls the recording head 0 via the discharge controller 12, controls the recovery unit 16 via the recovery controller 15, and controls the wipe unit 19 via the wipe controller 18. I do. Although not shown, the relative movement between the recording head 0 and the recording member 68 is also controlled.

  An output image from the observation unit 14 is input to the mixed liquid discrimination processing unit 13 and is subjected to image processing by a predetermined image processing program by an internal image processing system. Here, an image of the liquid adhering to the face surface is acquired, and position information and type of the liquid adhering to the face surface are specified by image processing. Whether the information obtained by the image processing and the information of the mixed liquid discrimination substance filled in each nozzle in advance are compared by the image processing program, and the result is output to the CPU 10, so that different liquids of each nozzle are mixed with each other. Whether or not is detected. The operation unit 17 is used to display information notified to the operator and to input an instruction from the operator.

  FIG. 6 is an operation flowchart of the ink jet recording apparatus in the present embodiment. Here, it is assumed that the same discharge liquid is supplied to a plurality of nozzles and that there are a plurality of such discharge liquids.

  After the start in S1, the recording head 0 (S2) is filled with a solution and a different mixture discrimination substance for each of those solutions (S3). Recovery (suction) of the recording head after filling is performed (S4), and first, the liquid attached to the face surface is imaged by focusing on the surface of the face (S5). S4 is not necessarily performed when printing is started without lapse of a predetermined time from the previous ejection. If the resolution of the observation unit 14 is not sufficient to detect the entire face surface in S5, the imaging area is divided into a plurality of parts (for example, divided imaging is performed as shown by the dotted line in FIG. 2). Further, when the entire face surface of the recording head 0 is imaged, when the depth of field of the observation unit 14 is shallow, the image is shaken and imaged.

  Next, the image of the liquid adhering to the surface of the face surface imaged in S5 is subjected to image processing, the position and type of the liquid adhering to the surface of each face surface are specified, and information on the mixed liquid discrimination substance filled in each nozzle in advance. In the mixed liquid discrimination process (S6), it is determined whether or not mixed liquid has occurred for all the nozzles filled with the discharged liquid, that is, whether or not it is a mixed liquid nozzle (S7). Based on the result, a nozzle for discharging is selected from the nozzles containing the same liquid (S8). If there are nozzles that are determined to be capable of discharging two or more of the same liquid, either one may be selected. After the ejection nozzle is determined in S8, wipe (S9), preliminary ejection (S10), and drawing (S11) are performed, and printing is completed (S12). On the other hand, if all of the nozzles containing the same liquid are liquid mixture nozzles, an error message and the address or / and liquid type of the liquid mixture nozzle are displayed on the operation unit 17 (S13). At that time, the operation of the apparatus stops halfway.

  Next, in S14, it is determined whether or not there is an amount of liquid that can be recovered again in the nozzle. If there is an amount of liquid that can be re-recovered, the process returns to S4, where only the nozzle in which the liquid mixture has occurred is recovered, and the process proceeds to S5 and subsequent steps. In S14, when the amount of liquid is insufficient to perform re-recovery, the process proceeds to S15, the same liquid as that in the nozzle is supplied to the spare nozzle by a pipetter or the like, and the process proceeds to S4 to perform a re-recovery operation. Thereafter, the process proceeds to S5 and subsequent steps. At that time, an address and a liquid type of the nozzle that supplies the liquid are input from the operation unit 17. The nozzle address and liquid type input here are added to the discharge nozzle selected in S8, and the liquid is discharged onto the recording material 68 at a position where it should be discharged.

[First embodiment]
As a first embodiment, a dye is used as a mixed liquid discrimination substance using a recording head having 16 nozzles (20 to 35) as shown in FIG. 7 and each nozzle having a separate flow path and reservoir. A mixed liquid inspection method using a CCD sensor as the observation means will be described below.

  After starting at S1, different sample solutions were dispensed into the 16 nozzles of the recording head of FIG. Furthermore, 16 types of pigments were prepared as mixed liquid discrimination substances, and one type of pigment was dispensed to each sample (S3). At that time, information on correspondence between the sample and the dye (which sample and which dye is dispensed to which place) is input from the operation unit 17 and stored in the memory 11.

  After the recording head is filled with the sample solution and a dye that is a mixture discrimination substance, the recording head is recovered (S4), and the face surface is observed with a CCD camera (S5), and an image as shown in FIG. Obtained.

  In S6, when the image obtained from the CCD camera was analyzed by color extraction using image processing software, a total of 6 droplets of 36 to 41 in FIG. Further, the CPU 10 compares the analysis result from the color extraction of the image processing software and the correspondence information between the sample and the dye stored in the memory 11, so that a mixed liquid discrimination process is performed. A discrimination result was obtained and an error message was displayed (S13).

  In Table 1, a mixed liquid was generated at nozzle number 22 and nozzle number 33. In FIG. 7 (d), it seems that a mixed liquid is also generated in the nozzle number 32, but from the color extraction result, the droplet 39 attached to the nozzle number 32 is the same sample solution as the nozzle number 32. It was determined that it was M, and it was found that it was not a mixed solution.

  Next, in S7, it is determined whether all the nozzles containing the same liquid are mixed liquid nozzles. In this case, since all the nozzles are filled with different sample solutions, the process proceeds to step S13.

  In S13, an error message indicating that a mixed liquid has occurred in the nozzle number 22 and the nozzle number 33 is displayed on the operation unit 17. Next, a mixed liquid handling process was performed.

  In S14, it was found that the sample solution in nozzle number 22 and nozzle number 33 in which the mixed liquid was generated has a sufficient amount of solution to perform the recovery operation again (the amount of solution supplied to the recording head in S3) It can be seen by taking the difference in the amount of solution recovered in S4), and proceeding to S4, both nozzles were recovered again. After re-recovery, as a result of proceeding to step S5 and subsequent steps, no liquid mixture was generated. Therefore, the process proceeds to S8, wipe is performed (S9), drawing is performed after preliminary ejection (S10) (S11), and printing is terminated. (S12).

[Second Embodiment]
As a second embodiment, a recording head having 16 nozzles (20 to 35) as shown in FIG. 7 and each nozzle having a separate flow path and a reservoir is used. A mixed liquid inspection method using a laser light source and a light receiving sensor as observation means will be described below.

  After starting in S1, 12 different sample solutions were dispensed into nozzle numbers 20-31 among the 13 nozzles (nozzle numbers 20-32) of the recording head of FIG. The same sample as nozzle number 28 was dispensed to nozzle number 32. Furthermore, 12 kinds of fluorescent dyes that emit fluorescence when excited at different wavelengths were prepared as mixed liquid discrimination substances, and one kind of fluorescent dye was dispensed to one type of sample (S3). The same mixture discrimination substance as nozzle number 28 was dispensed into nozzle number 32. At that time, information on the correspondence between the sample and the fluorescent dye (which sample and which fluorescent dye are dispensed to which location, and at which wavelength each fluorescent dye is excited to emit fluorescence) is input from the operation unit 17. And stored in the memory 11.

  The recording head is filled with a fluorescent dye, which is a sample solution and a mixture discrimination substance, and then the recording head is recovered (S4). The face surface is irradiated with laser light while changing the excitation wavelength of the laser light source. The light quantity with respect to the wavelength was measured (S5).

  In S6, the amount of light obtained at each wavelength is imaged, and when all the images are overlaid with image processing software, an image as shown in FIG. 8 is obtained, and the liquid adhering to the face surface is 42 to 48. It was found that there are a total of seven. Furthermore, by using the image processing software, the CPU 10 compares the information on the position coordinates of each liquid and the amount of light obtained at each wavelength with the information on the correspondence between the sample and the fluorescent dye stored in the memory 11, thereby mixing the liquid mixture. The mixed liquid discrimination result as shown in Table 2 was obtained, and an error message was displayed (S13).

  In Table 2, a mixed liquid was generated at nozzle number 28 and nozzle number 30.

  Next, in S7, it is determined whether all the nozzles containing the same liquid are mixed liquid nozzles. In this case, the same sample as the nozzle number 28 in which the mixed liquid is generated is filled in the nozzle number 32, and the nozzle number. Since no liquid mixture was generated at 32, it was decided to perform discharge at nozzle number 32 instead of nozzle number 28 in the selection of the discharge nozzle at S8. On the other hand, the nozzle number 30 in which the mixed liquid was generated did not fill the other liquid with the same liquid, and thus proceeded to step S13.

  In S13, an error message indicating that a mixed liquid has occurred at the nozzle number 30 is displayed on the operation unit 17. Next, a mixed liquid handling process was performed.

  In S14, it was found that the sample solution in the nozzle number 30 in which the mixed liquid was generated has a sufficient amount of solution to perform the recovery operation again (the amount of solution supplied to the recording head in S3 and the recovery in S4) It can be seen by taking the difference in the amount of solution obtained), and proceeded to S4 to perform recovery again. As a result of proceeding to step S5 and subsequent steps after the re-recovery, a mixed liquid error message was displayed again for the nozzle number 30, so the mixed liquid handling process was performed again.

  In S14, since it was found that the sample solution in the nozzle number 30 where the mixed liquid was generated does not have a sufficient amount of solution to perform the recovery operation again, the sample solution K and the nozzle number 33, which is a spare nozzle, are transferred. The same mixture discrimination substance as that dispensed to nozzle number 30 was again dispensed. Then, it progressed to S4, it recovered, and as a result of progressing to the step below S5, it turned out that no liquid mixture has arisen in all the nozzles.

  Thereafter, the process proceeds to S8, wipe is performed (S9), drawing is performed after preliminary ejection (S10) (S11), and printing is terminated (S12).

  In this embodiment, the face surface is observed after the recovery of S4 and the mixed liquid discrimination process is performed. However, the timing of performing the mixed liquid discrimination process is not necessarily assumed only after S4. For example, by observing the face surface again after performing the wipe in S9 and performing the mixed liquid discrimination process, it is possible to know the mixed liquid by the wipe, perform the mixed liquid corresponding process, and avoid the mixed liquid. Furthermore, between the first discharge operation and the next discharge operation, the face surface is observed and mixed liquid discrimination processing is performed to determine the mixed liquid due to mist generated during the drawing adhering to the face surface, By performing the mixed solution treatment, mixed solution can be avoided. Further, it may be confirmed in advance whether or not there is a cause of liquid mixture by observing an object adhering to the face surface before filling the recording head in S3.

  Further, in this embodiment, different discriminating substances are filled for each nozzle of the recording head to be used, and the mixed liquid is discriminated by recognizing the difference between them, but all different discriminating substances must be used. Do not mean. For example, mixed determination may be performed using the same determination substance for nozzles that are separated from each other by a distance that would not allow mixed liquid.

Overall perspective view of inkjet recording apparatus Diagram showing the face of recording head 0 Detailed view of nozzle 1 View of the face with liquid attached from the face side Control block diagram of inkjet recording apparatus Example Operation Flowchart The figure which shows the mode of the face surface at the time of the face surface observation of Example 1 The figure which shows the mode of the face surface at the time of the face surface observation of Example 2.

Explanation of symbols

0 Recording head 1 Nozzle 2 Nozzle port 3 Heater board 4 Orifice plate 5 Supply hole 6 Nozzle port 7 Droplet 10 CPU
DESCRIPTION OF SYMBOLS 11 Memory 12 Discharge controller 13 Liquid mixture discrimination | determination processing part 14 Observation means 15 Recovery controller 16 Recovery unit 17 Operation part 18 Wipe controller 19 Wipe unit 20-35 Nozzle port 36-41 Droplet 42-48 containing a sample and a pigment Sample and fluorescence Dye-containing droplet 53 Y-axis stage 54 X-axis stage 55 Chuck θ stage 56 Chuck 57, 58 Guide rail 59 Surface plate 61 Head θ stage 63, 64 Bridge 65, 66 Post 68 Recording member

Claims (46)

  In a liquid ejecting apparatus that records on a recording medium by ejecting a plurality of types of liquid, a recording head that holds a different mixed liquid discrimination substance for each of the plurality of types of liquid, and a recovery means for recovering the recording head; Observation means for observing the recording head from the face surface side, and processing the observed image to detect the liquid state of the face surface, and whether or not the liquid of each nozzle in the recording head is mixed. A liquid discharge apparatus comprising: a mixed liquid determination unit for determining.   2. The liquid ejection apparatus according to claim 1, further comprising ejection nozzle control means for determining whether or not each nozzle in the recording head is ejected based on information from the mixed liquid discrimination means.   The liquid ejection apparatus according to claim 1, further comprising a recovery control unit that determines whether or not to operate the recovery unit based on information from the liquid mixture determination unit.   2. A wiping means for wiping the recording head, and a wipe control means for determining whether or not to operate the wiping means based on information from the mixed liquid discrimination means. The liquid discharge apparatus according to 1.   2. The liquid ejection apparatus according to claim 1, wherein the liquid state on the face surface is at least one of the states of presence / absence of liquid adhered to the face surface, position of the liquid, and type of liquid.   The liquid ejection apparatus according to claim 1, wherein the mixed liquid discrimination substance is a pigment.   The liquid ejection apparatus according to claim 1, wherein the mixed liquid discrimination substance is a fluorescent dye.   The liquid ejecting apparatus according to claim 1, wherein the observation unit includes a CCD sensor and optically detects the liquid adhering to the face surface.   The observation means includes a laser light source and a light receiving sensor, and detects the liquid adhering to the face surface from a change in received light intensity of a laser beam passing through the liquid adhering to the face surface. Item 2. The liquid ejection device according to Item 1.   The liquid ejection apparatus according to claim 6, wherein the liquid mixture discrimination unit discriminates a liquid mixture by determining a difference in pigment by image processing based on information from the observation unit.   8. The liquid ejecting apparatus according to claim 7, wherein the liquid mixture discriminating unit discriminates a liquid mixture by determining a difference in fluorescent dye by image processing based on information from the observation unit.   It has nozzle replacement means for replacing the nozzles in the recording head, and has nozzle replacement control means for determining whether or not to operate the nozzle replacement means based on information from the mixed liquid discrimination means. The liquid ejection apparatus according to claim 1, wherein   When the information from the mixed liquid determining means is a determination result that mixed liquid has occurred for the nozzle that was scheduled to be discharged, the liquid mixed determining means includes a discharge nozzle control means that prohibits discharge from the nozzle. The liquid ejecting apparatus according to claim 2, wherein the liquid ejecting apparatus is a liquid ejecting apparatus.   If the information from the mixed liquid determining means is a determination result that a mixed liquid has occurred for a nozzle that was scheduled to be ejected, a recovery control means that performs suction or pressure recovery on the nozzle The liquid ejecting apparatus according to claim 3, wherein   If the information from the mixed liquid determining means is a determination result that a mixed liquid has occurred for a nozzle that was scheduled to be ejected, a wipe control means for performing a wiping operation on the nozzle is provided. The liquid discharge apparatus according to claim 4, wherein:   Whether or not to replace other nozzles in the recording head is determined if the mixed liquid cannot be avoided even by the recovery operation by the recovery control means. 13. The liquid ejecting apparatus according to claim 12, further comprising a nozzle replacement control means for determining.   The liquid ejection apparatus according to claim 1, wherein the liquid mixture is discriminated by the liquid mixture discriminating unit after the recovery unit of the recording head.   The liquid ejection apparatus according to claim 1, wherein the liquid mixture is discriminated by the liquid mixture discriminating unit after the wiping unit of the recording head.   The liquid ejection apparatus according to claim 1, wherein the mixed liquid discrimination unit performs the mixed liquid discrimination before the recording head discharge operation.   The liquid discharge apparatus according to claim 1, wherein after the discharge operation of the recording head, the mixed liquid determination unit performs mixed liquid determination.   The liquid ejection apparatus according to claim 1, wherein the liquid mixture is discriminated by the liquid mixture discrimination unit before the liquid is supplied to the recording head.   The liquid ejection apparatus according to claim 1, wherein the recording head is a bubble jet (registered trademark) type head including an electrothermal transducer that generates thermal energy to cause film boiling.   The liquid ejecting apparatus according to claim 1, wherein the recording head is a head of a system in which pressure is applied to a liquid chamber in a nozzle by a piezo element and a liquid droplet is ejected for recording.   In a liquid ejection method in which a plurality of types of liquids are ejected to perform recording on a recording medium, a step of observing a recording head that holds different liquid mixture discrimination substances for each of the plurality of types of liquids, and processing the observed images Detecting the state of the liquid on the face surface and determining whether or not the liquid in each nozzle in the recording head is mixed.   25. The liquid discharge method according to claim 24, further comprising a step of determining whether or not to discharge each nozzle in the recording head based on information from the mixed liquid determination step.   25. The liquid ejection method according to claim 24, further comprising a step of determining whether or not to operate the recovery step based on information from the mixed liquid discrimination step.   25. The liquid ejection method according to claim 24, further comprising a step of determining whether or not to operate the wiping step based on information from the mixed liquid discrimination step.   25. The liquid ejection method according to claim 24, wherein the liquid state on the face surface is at least one of the states of presence / absence of liquid adhering to the face surface, liquid position, and liquid type.   25. The liquid ejection method according to claim 24, wherein the mixed liquid discrimination substance is a pigment.   25. The liquid ejection method according to claim 24, wherein the mixed liquid discrimination substance is a fluorescent dye.   25. The liquid ejection method according to claim 24, wherein the observing step includes a step of optically detecting a liquid that is composed of a CCD sensor and adheres to the face surface.   The observing step includes a laser light source and a light receiving sensor, and includes a step of detecting liquid adhering to the face surface from a change in received light intensity of a laser beam passing through the liquid adhering to the face surface. The liquid discharge method according to claim 24.   25. The liquid ejection method according to claim 24, wherein the liquid mixture discrimination step includes a step of discriminating a liquid mixture by determining a difference in pigment by image processing based on information from the observation step.   25. The liquid ejection method according to claim 24, wherein the liquid mixture discrimination step includes a step of discriminating a liquid mixture by determining a difference in fluorescent dye by image processing based on information from the observation step. .   25. The liquid ejection method according to claim 24, further comprising a step of determining whether or not to operate the nozzle replacement step based on information from the mixed liquid discrimination step.   When the information from the mixed liquid determining step is a determination result that mixed liquid has occurred for the nozzle that was scheduled to be discharged, the method includes a step of prohibiting discharge from the nozzle. The liquid ejection method according to claim 25.   If the information from the mixed liquid determination step is a determination result that a mixed liquid has occurred for a nozzle that was scheduled to be discharged, a step of performing suction or pressure recovery on the nozzle is included. 27. The liquid ejection method according to claim 26.   A step of performing a wiping operation on the nozzle when the information from the mixed liquid determining step is a determination result that mixed liquid has occurred for the nozzle that was scheduled to be discharged; The liquid ejection method according to claim 27.   Whether or not to replace other nozzles in the recording head is determined if the mixed liquid cannot be avoided by the recovery operation in the recovery control process. 36. The liquid ejection method according to claim 35, further comprising a determining step.   25. The liquid ejection method according to claim 24, wherein the mixed liquid is discriminated by the mixed liquid discriminating step after the recovery step of the recording head.   25. The liquid ejection method according to claim 24, wherein after the wiping process of the recording head, the mixed liquid is determined by the mixed liquid determining process.   25. The liquid ejection method according to claim 24, wherein the mixed liquid is discriminated by the mixed liquid discrimination step before the ejection operation of the recording head.   25. The liquid discharge method according to claim 24, wherein after the discharge operation of the recording head, the mixed liquid is determined by the mixed liquid determining step.   25. The liquid ejection method according to claim 24, wherein the liquid mixture is discriminated by the liquid mixture discrimination step before the liquid is supplied from the recording head.   25. The liquid ejection method according to claim 24, wherein the recording head is a bubble jet (registered trademark) type head including an electrothermal transducer that generates thermal energy to cause film boiling.   25. The liquid ejection method according to claim 24, wherein the recording head is a head of a system in which pressure is applied to a liquid chamber in a nozzle by a piezo element and liquid droplets are ejected for recording.