JP5263212B2 - Liquid ejection apparatus, inspection method thereof, and program - Google Patents

Description

  The present invention relates to a liquid ejection apparatus that forms an image on a recording medium, an inspection method thereof, and a program.

  In Patent Document 1, a color ink discharge unit that discharges color ink, a clear ink discharge unit that discharges a colorless and transparent liquid (clear ink) that improves the image quality of a printed image, and ink is discharged from each discharge unit onto a medium. A printing apparatus having a sensor for detecting an inspection pattern formed in this manner is described. In this printing apparatus, first, the clear ink is ejected from the clear ink ejection unit to the recording medium in a predetermined pattern, and the predetermined pattern is formed from the color ink ejection unit on the pattern formed by the ejected clear ink. It is formed by discharging colored ink in a pattern. Then, the sensor checks the inspection pattern and outputs the received light amount to the system controller. The system controller compares the amount of received light output from the sensor with a predetermined threshold value stored in advance, and determines whether each nozzle constituting the clear ink discharge unit has a discharge failure.

JP 2005-22216 A

  However, in the printing apparatus described in Patent Literature 1, since the threshold value stored in advance and the amount of received light detected by the sensor are compared, for example, the amount of light output from the light emitting unit of the sensor decreases, If sensor deterioration occurs that also reduces the amount of light detected from the test pattern, the sensor will be used even if clear ink is normally ejected from each nozzle that forms the clear ink ejection section and the test pattern is formed. Since the amount of received light of the inspection pattern detected in (2) is reduced, it is determined that a discharge failure has occurred in the nozzle. That is, it cannot be accurately determined whether or not a discharge failure has occurred in the nozzle. Furthermore, the amount of light received by the inspection pattern detected by the sensor even when there are variations in the quality of the media (such as variations in liquid absorption such as clear ink and color ink) and deterioration of the clear ink and color ink itself. Therefore, as described above, it is impossible to accurately determine whether or not ejection failure has occurred in each nozzle constituting the clear ink ejection unit.

  Accordingly, an object of the present invention relates to a liquid recording apparatus having a discharge port that discharges a liquid with low visibility, such as a processing liquid that is used by being superimposed on ink on a recording medium, and accurately determines the quality of the discharge state from the discharge port. It is an object to provide a liquid ejecting apparatus that can be performed, an inspection method thereof, and a program.

  The liquid ejection apparatus according to the present invention includes a conveyance mechanism that conveys the recording medium in the conveyance direction, and a plurality of first ejection ports for ejecting ink to the recording medium that is arranged at equal intervals in a direction orthogonal to the conveyance direction. A plurality of first ejection heads arranged along the transport direction and ejecting inks of different colors, and arranged at the same intervals as the first ejection ports in the orthogonal direction to act on the ink. A second ejection head having a plurality of second ejection ports for ejecting a liquid for aggregating or precipitating the components therein to a recording medium, and disposed upstream of the first ejection head in the transport direction; The liquid is ejected from at least one of the plurality of second ejection openings toward the recording medium to form a first liquid adhesion area, and the first liquid adhesion area and the first liquid adhesion are formed. region One or more of the first liquid non-adhering areas, which are areas different from the first liquid adhering area on the same recording medium as the formed recording medium and where the liquid does not adhere to the recording medium. First test pattern formation control means for controlling one or more of the first ejection head and the second ejection head so that ink is ejected from the first ejection port of the ejection head to form a first test pattern; A recording medium on which the liquid is discharged from the at least one second discharge port toward the recording medium to form a second liquid adhesion area, and the second liquid adhesion area and the second liquid adhesion area are formed; The first test pattern is formed in a second liquid non-adhesion area which is an area different from the second liquid adhesion area on the same recording medium and where the liquid does not adhere to the recording medium. One or more first ejection heads are formed such that ink is ejected from the first ejection ports of one or more first ejection heads other than the first ejection head ejected at the time of forming the second test pattern. And second test pattern formation control means for controlling the second ejection head, density detection means for detecting the density of the first and second test patterns, and the density of the first test pattern detected by the density detection means. The first calculation means for calculating a first concentration ratio value, which is the ratio of the concentration values of the first liquid adhesion area and the first liquid non-adhesion area, and the second test pattern detected by the concentration detection means. Based on the concentration, a second calculation unit that calculates a second concentration ratio value that is a ratio of the concentration values of the second liquid adhesion region and the second liquid non-adhesion region; and the first calculation unit calculated by the first calculation unit. Concentration ratio Third calculation means for calculating an evaluation value that is a ratio between the value and the second concentration ratio value calculated by the second calculation means; reference storage means for storing a reference value of the evaluation value; and the three calculation Determination means for determining whether or not the evaluation value calculated by the means is within a predetermined range centered on the reference value stored in the reference storage means.

  An inspection method for a liquid ejection apparatus according to the present invention includes a transport mechanism for transporting a recording medium in a transport direction, and a plurality of firsts for ejecting ink onto a recording medium arranged at equal intervals in a direction orthogonal to the transport direction. A plurality of first ejection heads that have ejection openings and are arranged along the transport direction and eject inks of different colors, and are arranged at the same interval as the first ejection openings in the orthogonal direction and act on the ink A second discharge head having a plurality of second discharge ports for discharging a liquid that agglomerates or deposits the components in the ink onto the recording medium, and is disposed upstream of the first discharge head in the transport direction. And a density detecting means for detecting the density on the recording medium, wherein the liquid is directed from the at least one second ejection port to the recording medium among the plurality of second ejection ports. A first liquid adhesion region forming step of forming a first liquid adhesion region by discharging, and the first liquid adhesion on the same recording medium as the recording medium on which the first liquid adhesion region and the first liquid adhesion region are formed Ink is ejected from the first ejection ports of one or more first ejection heads to a first liquid non-adhesion area, which is an area different from the area and where the liquid does not adhere to the recording medium. A first test pattern forming step for forming a test pattern; a second liquid adhesion region forming step for ejecting the liquid from the at least one second ejection port toward a recording medium to form a second liquid adhesion region; The second liquid adhesion area and the recording medium on which the second liquid adhesion area is formed are different from the second liquid adhesion area on the same recording medium, and the liquid adheres to the recording medium. Ink is ejected from the first ejection ports of one or more first ejection heads other than the first ejection head ejected when the first test pattern is formed in the second liquid non-adhering area, which is a large area. In a second test pattern forming process for forming a second test pattern, a density detection process for detecting the density of the first and second test patterns formed on the recording medium by the density detection means, and the density detection process, A first calculation for calculating a first concentration ratio value, which is a ratio between the density values of the first liquid adhering region and the first liquid non-adhering region, by detecting the concentration of the first test pattern by the concentration detecting unit. And in the step of detecting the concentration, the concentration of the second test pattern is detected by the concentration detection means, whereby the concentration of the second liquid adhesion region and the second liquid non-adhesion region is detected. A second calculation step of calculating a second concentration ratio value that is a ratio of the values; the first concentration ratio value calculated in the first calculation step; and the second concentration ratio calculated in the second calculation step. A third calculation step of calculating an evaluation value that is a ratio to the value, and determining whether or not the evaluation value calculated in the third calculation step is within a predetermined range centered on a stored reference value Determination step.

  A program for a liquid ejection apparatus according to the present invention includes a transport mechanism that transports a recording medium in a transport direction, and a plurality of first discharges for ejecting ink onto a recording medium that is arranged at equal intervals in a direction orthogonal to the transport direction. A plurality of first ejection heads that have outlets and are arranged along the transport direction and eject inks of different colors, and are arranged at the same intervals as the first ejection ports in the orthogonal direction and act on the ink; A second ejection head having a plurality of second ejection openings for ejecting a liquid that agglomerates or deposits the components in the ink onto a recording medium, and is disposed upstream of the first ejection head in the transport direction; And a computer that controls the liquid ejection device having a density detection unit that detects density on the recording medium from the at least one second ejection port of the plurality of second ejection ports toward the recording medium. An area different from the first liquid adhesion area on the same recording medium as the first liquid adhesion area and the recording medium on which the first liquid adhesion area is formed is formed by discharging liquid. Ink is ejected from the first ejection ports of one or more first ejection heads to a first liquid non-adhesion area, which is an area where the liquid does not adhere to the recording medium, thereby forming a first test pattern. As described above, the first test pattern formation control means for controlling the one or more first ejection heads and the second ejection heads, the second liquid ejecting the liquid from the at least one second ejection port toward the recording medium. A liquid adhesion region is formed, and the second liquid adhesion region and the recording medium on which the second liquid adhesion region is formed are different from the second liquid adhesion region on the same recording medium. The one or more first ejection heads other than the first ejection head ejected when forming the first test pattern in the second liquid non-adhesion area, which is an area where the liquid does not adhere to the recording medium. Second test pattern formation control means for controlling one or more of the first ejection head and the second ejection head so that ink is ejected from the first ejection port to form a second test pattern, and the first test pattern A first calculating means for calculating a first concentration ratio value, which is a ratio between the concentration values of the first liquid adhering region and the first liquid non-adhering region, by detecting the concentration of Second calculation means for calculating a second concentration ratio value, which is a ratio of the concentration values of the second liquid adhesion region and the second liquid non-adhesion region, by detecting the concentration of the test pattern by the concentration detection unit; Third calculation means for calculating an evaluation value that is a ratio between the first concentration ratio value calculated by the first calculation means and the second concentration ratio value calculated by the second calculation means; It is determined whether or not the evaluation value calculated by the reference storage means for storing the reference value and the three calculation means is within a predetermined range centered on the reference value stored in the reference storage means. It functions as a determination means.

  In another aspect, the liquid ejection apparatus according to the present invention includes a transport mechanism that transports the recording medium in the transport direction, and a plurality of inks for ejecting ink onto a recording medium that is arranged at equal intervals in a direction orthogonal to the transport direction. A plurality of first ejection heads that have first ejection ports and are arranged along the transport direction and eject inks of different colors, and inks that are arranged at the same intervals as the first ejection ports in the orthogonal direction A second discharge port disposed on the upstream side of the first discharge head with respect to the transport direction. The second discharge port has a plurality of second discharge ports for discharging a liquid that agglomerates or precipitates the components in the ink to the recording medium. An ejection head, a first specific ink ejection head that is one or more first ejection heads, and a second specific ink ejection head that is one or more first ejection heads other than the first specific ink ejection head are selected. A liquid ink adhesion region which is a region where both the ink and the liquid adhere to the recording medium by controlling the selection means, the first and second specific ink ejection heads, the second ejection head, and the transport mechanism The liquid ink adhesion area formation control means for forming the first and second specific ink ejection heads and the transport mechanism are controlled to form an ink adhesion area, which is an area where only the ink is adhered, on the recording medium. From the ink adhesion area formation control means, the density detection means for detecting the density of the liquid ink adhesion area and the ink adhesion area, and the density of the liquid ink adhesion area and the ink adhesion area detected by the density detection means, A density ratio calculating means for calculating a density ratio value, which is a ratio between the density of the liquid ink adhesion area and the ink adhesion area, and the density ratio calculation means. Evaluation value calculation means for calculating an evaluation value that is a ratio of two different density ratio values, reference storage means for storing a reference value of the evaluation value, and the evaluation value calculated by the evaluation value calculation means And a determination unit that determines whether or not the value is within a predetermined range centered on the reference value stored in the reference storage unit, wherein the selection unit includes the first and second selection units. A specific ink ejection head is selected, and for one or a plurality of recording media, the liquid ink adhering region formation control means is configured to transfer the one or more recording media from at least one second ejection port out of the plurality of second ejection ports. The liquid is ejected toward one of the recording media to form a first liquid adhesion region, and ink is ejected from the first ejection port of the first specific ink ejection head to the first liquid adhesion region. Vomiting Forming a first liquid ink adhering region, and discharging the liquid from the at least one second discharge port toward any one of the one or the plurality of recording media. A second liquid adhesion region is formed, and ink is ejected from the first ejection port of the second specific ink ejection head to the second liquid adhesion region to form a second liquid ink adhesion region. A region formation control unit discharges ink from the first discharge port of the first specific ink discharge head toward one of the one or a plurality of recording media to thereby form a first ink adhesion region. And ejecting ink from the first ejection port of the second specific ink ejection head toward any one of the one or the plurality of recording media to form a second ink adhesion region Forming The density detection means detects the density of the first and second liquid ink adhesion areas and the density of the first and second ink adhesion areas, and the density ratio calculation means detects the density detection means by the density detection means. A first density ratio value, which is a ratio of the density values of the first liquid ink adhesion area and the first ink adhesion area, and the density of the second liquid ink adhesion area and the second ink adhesion area. A second concentration ratio value that is a ratio of the values is calculated, the evaluation value calculating means calculates the evaluation value related to a ratio of the first concentration ratio value and the second concentration ratio value, and the determining means includes: It is determined whether or not the evaluation value relating to the ratio between the first concentration ratio value and the second concentration ratio value is within a predetermined range centered on the reference value.

  In another aspect, the inspection method for a liquid ejection apparatus of the present invention is for ejecting ink to a transport mechanism that transports a recording medium in the transport direction and to a recording medium that is arranged at equal intervals in a direction orthogonal to the transport direction. And a plurality of first ejection heads that are arranged along the transport direction and eject inks of different colors, and at the same interval as the first ejection ports in the orthogonal direction. It has a plurality of second discharge ports for discharging to the recording medium a liquid that is arranged and acts on the ink to aggregate or deposit the components in the ink, and is disposed upstream of the first discharge head in the transport direction. The second ejection head, the plurality of first ejection heads, the second ejection head, and the transport mechanism are controlled, and the liquid ink adhesion is a region where both the ink and the liquid are adhered to the recording medium. Ink adhesion for forming an ink adhesion area, which is an area where only the ink is adhered on the recording medium, by controlling the liquid ink adhesion area formation control means for forming the area, the plurality of first ejection heads and the transport mechanism In a method for inspecting a liquid ejection apparatus including a region formation control unit, one or more first ejection heads that are one or more first ejection heads and one or more first ejection heads other than the first particular ink ejection head In the head selection step of selecting the second specific ink ejection head and the one or a plurality of recording media, the liquid ink adhesion region formation control means starts from at least one second ejection port among the plurality of second ejection ports. The liquid is ejected toward one of the one or a plurality of recording media to form a first liquid adhering region, and the first liquid adhering A first liquid ink adhesion region forming step of forming a first liquid ink adhesion region by ejecting ink from the first ejection port of the first specific ink ejection head to the area, and the liquid ink adhesion region formation control means However, the liquid is ejected from the at least one second ejection port toward any one of the one or a plurality of recording media to form a second liquid adhesion region, and the second liquid A second liquid ink adhesion region forming step of forming a second liquid ink adhesion region by ejecting ink from the first ejection port of the second specific ink ejection head to the adhesion region; and the ink adhesion region formation system. Then, ink is ejected from the first ejection port of the first specific ink ejection head toward any one of the one or a plurality of recording media to form a first ink adhesion region. The first ink adhering area forming step and the ink adhering area forming system are transferred from the first ejection port of the second specific ink ejection head to any one of the one or a plurality of recording media. A second ink adhesion region forming step of forming a second ink adhesion region by ejecting ink toward the ink, and the concentrations of the first and second liquid ink adhesion regions and the first and second ink adhesion regions A first density ratio that is a ratio of a density value of the first liquid ink adhesion area and the first ink adhesion area detected in the density detection process. A second density ratio value for calculating a second density ratio value, which is a ratio of the density value of the second liquid ink adhering area and the second ink adhering area detected in the ratio value calculating step and the density detecting step; Calculation step and the first concentration ratio value An evaluation value calculating step for calculating an evaluation value that is a ratio of the first concentration ratio value calculated in the exiting step and the second concentration ratio value calculating step in the second concentration ratio value calculating step; and the evaluation value A determination step of determining whether or not the evaluation value calculated in the calculation step is within a predetermined range centered on a predetermined reference value.

  According to these, it is possible to determine whether or not the evaluation value that is the ratio of the first concentration ratio value and the second concentration ratio value is within a predetermined range centered on the reference value. For this reason, for example, even if the detection sensitivity of the density detecting means for detecting the density of each test pattern is deteriorated, even if the liquid and ink absorption varies in the same type of recording medium, the viscosity of the liquid itself is aged over time. Even if deterioration and aging deterioration of ink coloring occur, the calculated evaluation value does not change due to these influences, and therefore it is possible to accurately determine the quality of the discharge state from the second discharge port of the second discharge head. It becomes possible.

  According to the present invention, it is possible to determine whether or not an evaluation value that is a ratio between the first concentration ratio value and the second concentration ratio value is within a predetermined range centered on the reference value. For this reason, it is possible to accurately determine the quality of the discharge state from the second discharge port of the second discharge head that discharges a liquid with low visibility, such as a processing liquid that is used to overlap the ink on the recording medium.

1 is a schematic side view showing an overall configuration of an inkjet printer according to a first embodiment of the present invention. It is a top view of the inkjet head shown in FIG. FIG. 3 is an enlarged view of a region surrounded by an alternate long and short dash line in FIG. 2. It is a fragmentary sectional view of the ink jet head shown in FIG. It is a block diagram which shows schematic structure of the control part shown in FIG. FIG. 6 is a diagram for explaining first and second test patterns printed by first and second test pattern formation control units shown in FIG. 5. It is an operation | movement condition figure for demonstrating purge operation | movement and wiping operation | movement. It is a flowchart at the time of test | inspecting the discharge state of the precoat liquid from each discharge port of the precoat head shown in FIG. It is a block diagram which shows schematic structure of the control part of the inkjet printer by 2nd Embodiment of this invention. It is a flowchart at the time of test | inspecting the discharge state of the precoat liquid from each discharge port of the precoat head of the inkjet printer by 2nd Embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the ink jet printer (liquid ejection device) 101 according to the first embodiment has a substantially rectangular parallelepiped casing 101a. In the housing 101a, a transport mechanism 16 that transports the paper P in the transport direction (the direction from the left to the right in FIG. 1), and the paper P transported by the transport mechanism 16 includes yellow, cyan, magenta, Four inkjet heads (first ejection heads) 1 for ejecting black ink droplets, a precoat head (second ejection head) 2 for ejecting droplets of a precoat liquid for aggregating or precipitating the pigment component of each ink, Pumps 32 (see FIG. 5) corresponding to the four inkjet heads 1 and the precoat head 2, an image sensor 30, a head lifting mechanism 33 (see FIG. 5), a wiper unit 36 (see FIG. 5), and a cleaner unit 37. A paper feeding unit 101b for feeding paper P, a tank unit 101c for storing ink and precoat liquid, and an inkjet printer. And a control unit 100 is provided for controlling the printer 101 overall. In addition, a paper discharge unit 15 for discharging the paper P is provided on the top plate of the housing 101a.

  In the present embodiment, the sub-scanning direction is a direction parallel to the transport direction when the paper P is transported by the transport mechanism 16, and the main scanning direction is a direction orthogonal to the sub-scanning direction and along the horizontal plane. Direction.

  The tank unit 101c accommodates four ink tanks 17a and one precoat liquid tank 17b. The ink tank 17a and the precoat liquid tank 17b are detachably attached to the tank unit 101c. Each ink tank 17a stores cyan, magenta, yellow, and black inks, respectively, and ink is supplied to the corresponding inkjet head 1 via an ink tube (not shown). Similarly, a precoat liquid is stored in the precoat liquid tank 17b, and the precoat liquid is supplied to the precoat head 2 through a tube. In general, a precoat liquid for aggregating pigment pigment is used for pigment ink, and a precoat liquid for depositing dye pigment is used for dye ink. The material of the precoat liquid can be appropriately selected from a liquid containing a polyvalent metal salt such as a cationic polymer or a magnesium salt. When the ink lands on the region of the paper P to which such a precoat liquid has been applied in advance, the polyvalent metal salt or the like acts on the dye or pigment that is the colorant of the ink, and the insoluble or hardly soluble metal composite or the like aggregates. Formed by precipitation.

  The paper feed unit 101b is detachably arranged with respect to the housing 101a, and includes a paper feed tray 11 and a paper feed roller 12. The paper feed tray 11 has a box shape opened upward, and stores a plurality of paper sheets P in a stacked state. The paper feed roller 12 sends out the paper P at the uppermost position of the paper feed tray 11 under the control of the control unit 100. The fed paper P is sent to the transport mechanism 16 by the feed roller pair 14 along the guides 13a and 13b.

  The transport mechanism 16 includes two belt rollers 6 and 7, a transport belt 8, a tension roller 10, and a platen 18. The conveyor belt 8 is an endless belt wound between both rollers 6 and 7, and tension is applied by a tension roller 10. The platen 18 is disposed to face the four inkjet heads 1 and the precoat head 2 and supports the upper loop of the conveyor belt 8 from the inside. Thereby, a predetermined gap suitable for image formation is formed between the outer peripheral surface of the conveyor belt 8 and the ejection surfaces of the four inkjet heads 1 and the precoat head 2. The belt roller 7 is a driving roller that is driven to rotate clockwise in FIG. 1 by a motor (not shown), and causes the conveyor belt 8 to travel. The belt roller 6 is a driven roller that rotates as the conveyor belt 8 travels. A weakly adhesive silicon layer is formed on the outer peripheral surface of the conveyor belt 8 and holds the loaded paper P. Accordingly, the transport mechanism 16 can transport the paper P placed on the transport belt 8 in the transport direction.

  The four inkjet heads 1 and the precoat head 2 have the same structure, extend along the main scanning direction, and are arranged in parallel and at equal intervals in the sub-scanning direction. The precoat head 2 is disposed on the upstream side in the transport direction of the four inkjet heads 1. The lower surfaces of the inkjet heads 1 and the precoat head 2 are ejection surfaces 1a and 2a in which a plurality of ejection ports (first and second ejection ports) 108 (see FIG. 3) are arranged. That is, the ink jet printer 101 is a line type color ink jet printer in which a plurality of ejection openings 108 for ejecting ink droplets in the main scanning direction are arranged.

  The four inkjet heads 1 are arranged so that ink with higher brightness is discharged toward the downstream. That is, the inkjet head 1 is arranged so that black ink is ejected from the inkjet head 1 arranged at the most upstream and ink is ejected in the order of magenta, cyan, and yellow toward the downstream.

  The outer peripheral surface of the upper loop of the conveyor belt 8 and the discharge surfaces 1a and 2a are parallel to each other while facing each other. When the paper P conveyed by the conveyance belt 8 passes just below the precoat head 2, the precoat liquid is applied from the precoat head 2 so that the precoat liquid is applied to the area on the upper surface of the paper P where the image is formed. A droplet is ejected. Thereafter, when the paper P passes just below the four inkjet heads 1, ink droplets of each color are sequentially ejected from each inkjet head 1 to a region where the precoat liquid is applied on the upper surface of the paper P. Thereby, a desired color image is formed on the paper P. At this time, when the ink droplets land on the precoat liquid applied on the paper P, the precoat liquid causes the pigment component of the ink droplets to aggregate or precipitate, so that ink bleeding on the paper P is prevented.

  A peeling plate 5 is disposed on the downstream side in the transport direction of the four inkjet heads 1. The sheet P transported in the transport direction by the transport mechanism 16 is sequentially peeled from the transport surface of the transport belt 8 by the stripping plate 5 after sequentially passing below the precoat head 2 and the four inkjet heads 1. The paper P peeled off by the peeling plate 5 is conveyed upward by the two pairs of feed rollers 28 along the guides 29a and 29b, and from the discharge port 22 formed in the upper part of the housing 101a to the paper discharge unit 15. Discharged.

  Next, the heads 1 and 2 will be described in detail with reference to FIGS. Note that the precoat head 2 has the same structure as the ink jet head 1, and therefore the description thereof is omitted. In FIG. 3, for convenience of explanation, the pressure chamber 110, the aperture 112, and the discharge port 108 that are to be drawn with broken lines below the actuator unit 21 are drawn with solid lines.

  As shown in FIG. 2, the inkjet head 1 is a laminated body in which four actuator units 21 are fixed to the upper surface 9 a of the flow path unit 9. Although not shown, the inkjet head 1 and the precoat head 2 are a flexible printed circuit board (a reservoir unit that stores ink (or precoat liquid) supplied to the flow path unit 9) and a flexible printed wiring board that supplies a drive signal to the actuator unit 21. Flexible Printed Circuit (FPC), and a control board for controlling a driver IC mounted on the FPC.

  As shown in FIG. 4, the flow path unit 9 is a laminated body in which a plurality of metal plates made of stainless steel are aligned with each other. In the flow path unit 9, there are many manifold channels 105 (see FIGS. 2 and 3) to the sub manifold flow path 105a, and from the outlet of the sub manifold flow path 105a to the discharge port 108 through the aperture 112 and the pressure chamber 110. The individual ink flow paths 109 are formed. The actuator unit 21 includes a plurality of actuators corresponding to the pressure chambers 110, and has a function of selectively giving ejection energy to the ink in the pressure chambers 110.

  As shown in FIG. 2, a total of ten ink supply ports 105b are opened on the upper surface 9a of the flow path unit 9 corresponding to the ink outflow flow paths of the reservoir unit. The lower surface of the flow path unit 9 is a discharge surface 1a, and a large number of discharge ports 108 are arranged in a matrix. The ejection ports 108 are arranged at an interval of 600 dpi, which is the resolution in the main scanning direction with respect to the main scanning direction.

  The ink flow in the flow path unit 9 will be described. As shown in FIGS. 3 and 4, the ink supplied from the reservoir unit into the flow path unit 9 via the ink supply port 105b is distributed from the manifold flow path 105 to the sub-manifold flow path 105a. The ink in the sub-manifold channel 105 a flows into each individual ink channel 109 and reaches the ejection port 108 via the pressure chamber 110.

  The pump 32 forces the ink to the ink supply port 105b of the flow path unit 9 via the reservoir unit so that the ink in the ejection port 108 is discharged to the outside in the corresponding inkjet head 1 or precoat head 2. Supply. Although one pump 32 is shown in FIG. 5, the ink jet printer 101 has five pumps 32 corresponding to the ink jet head 1 and the precoat head 2.

  The image sensor (a part of the density detecting means) 30 is disposed on the downstream side in the transport direction of the four inkjet heads 1 so as to face the printing surface of the paper P transported by the transport belt 8. The image sensor 30 has a plurality of sensor elements arranged in the main scanning direction on the surface facing the conveyance belt 8. Each sensor element of the image sensor 30 includes a light emitting unit that emits light to the paper P and a light receiving unit that receives light reflected from the paper P. Then, the image sensor 30 outputs the received light amount detected by the light receiving unit of each element from the image formed on the paper P to the control unit 100 according to a command from the control unit 100. That is, the image sensor 30 can detect the density of the image printed on the paper P according to a command from the control unit 100. The density detection means includes at least the image sensor 30 and a control unit 100 that controls the operation of the image sensor 30.

  The plurality of sensor elements are arranged so as to have a width equal to or larger than the maximum width formed by the plurality of ejection openings 108 of the heads 1 and 2 in the main scanning direction. That is, the plurality of sensor elements are arranged so as to detect the density related to the image formed by the heads 1 and 2 and having the maximum width in the main scanning direction. Further, the intervals between the sensor elements adjacent in the main scanning direction are arranged at the same interval as the interval between the adjacent ejection ports 108 of the heads 1 and 2. That is, the image sensor 30 can detect the density of the image formed on the paper P with the same resolution as the print resolution in the main scanning direction in each of the heads 1 and 2. Specifically, it is possible to detect the density of each dot area where the precoat liquid and ink ejected from the heads 1 and 2 have landed. In addition, the light receiving unit of each sensor element recognizes the image size for each dot area as well as the amount of light received. Therefore, the image sensor 30 also outputs the image size for each dot area to the control unit 100.

  The four inkjet heads 1 and the precoat head 2 and the image sensor 30 are fixed to a frame 35 as shown in FIG. The head elevating mechanism 33 determines the “printing position” (see FIG. 1) for discharging the precoat liquid and ink from the heads 1 and 2 to the paper P during printing, and the separation distance between the heads 1 and 2 and the transport mechanism 16. The frame 35 is moved up and down so as to move the heads 1 and 2 between the “retracted position” (see FIG. 7B) that is further away from the head. In addition, a space in which the wiper unit 36 can be disposed is formed between the heads 1 and 2 moved to the retracted position by the head lifting mechanism 33 and the transport mechanism 16. As a result, it is possible to dispose the wiper unit 36, which is normally waiting in the main scanning direction with respect to this space, to wipe the ejection surfaces 1a, 2a of the heads 1, 2 in this space.

  The wiper unit 36 has five wipers 36a (see FIG. 7) that are plate members made of an elastic material such as rubber for wiping the discharge surfaces 1a and 2a in a wiping operation described later. In FIG. 7, only one wiper 36a is shown. The wiper unit 36 wipes the ejection surfaces 1a and 2a by moving the wiper 36a along the main scanning direction while contacting the ejection surfaces 1a and 2a of the heads 1 and 2.

  The cleaner unit 37 cleans the outer peripheral surface of the conveyor belt 8. The cleaner unit 37 is disposed on the lower right side of the conveyor belt 8 in FIG. 1, and includes a cleaning liquid application member 37a and a blade 37b. The cleaning liquid application member 37 a has a porous body that holds the cleaning liquid supplied from a cleaning liquid tank (not shown) while extending so as to face the entire width direction of the transport belt 8. The blade 37b is disposed immediately downstream of the cleaning liquid application member 37a with respect to the rotation direction of the conveyance belt 8, and is a plate made of an elastic material such as rubber that extends so as to face the entire width direction of the conveyance belt 8. It is a member.

  The cleaning liquid applying member 37a and the blade 37b are moved by a moving mechanism (not shown), a contact position where the porous body of the cleaning liquid applying member 37a and the tip of the blade 37b contact the outer peripheral surface of the transport belt 8, and a porous position of the cleaning liquid applying member 37a. The body and the tip of the blade 37b can be selectively taken away from the outer peripheral surface of the conveyor belt 8. In the cleaning operation described later, the cleaner unit 37 moves the cleaning liquid application member 37a and the blade 37b to the contact positions. At this time, when the conveying belt 8 rotates clockwise, the cleaning liquid application member 37a applies the cleaning liquid to the outer peripheral surface of the conveying belt 8, and the blade 37b scrapes off the dirt attached to the outer peripheral surface of the conveying belt 8 together with the cleaning liquid. . The cleaning liquid scraped off by the blade 37b flows into a waste liquid tank (not shown).

  Next, the control unit 100 will be described with reference to FIG. The control unit 100 includes a CPU (Central Processing Unit), a program executed by the CPU, and an EEPROM (Electrically Erasable and Programmable Read Only Memory) that stores data used for the program in a rewritable manner. It includes RAM (Random Access Memory) for temporary storage. The control program of the present invention is stored in various recording media such as a flexible disk, a CD-ROM, and a memory card, and is installed in the EEPROM from these recording media. Then, when the control program is executed by the CPU, each functional unit constituting the control unit 100 shown in FIG. 5 is realized. The control program recorded on the recording medium may be directly executable by the control unit 100, or may be executable only after being installed in the EEPROM. Further, it may be encrypted or compressed.

  As shown in FIG. 5, the control unit 100 controls the entire inkjet printer 101, and includes a conveyance control unit 130, an image data storage unit 131, a head control unit 132, a first test pattern formation control unit 135, and a second test unit. Test pattern formation control unit 136, first calculation unit 141, second calculation unit 142, third calculation unit 143, reference value storage unit 144, precoat liquid discharge determination unit 145, ink discharge determination unit 146, droplet size determination unit 147 , A purge controller 151, a head lifting controller 152, a wiper controller 153, and a cleaner controller 154.

  The transport control unit 130 controls the paper feed unit 101b, the feed roller pairs 14, 28, and the transport mechanism 16 so that the paper P is transported along the transport direction.

  The image data storage unit 131 uses image data concerning an image printed on a paper P transferred from a PC (Personal Computer) or the like as ejection data of ink from each inkjet head 1 and precoat liquid from the precoat head 2. I remember it. In the present embodiment, the discharge data indicates whether the amount of ink or precoat liquid discharged from each discharge port 108 for each printing cycle is four types (zero, small amount, medium amount, large amount). Yes. The precoat liquid ejection data is determined based on the image data. Specifically, the precoat liquid is determined to land on the dot area where the ink ejected from the inkjet head 1 lands based on the image data. That is, the precoat liquid is discharged to the area where the image is formed, and the precoat liquid is not discharged to the area where the image is not formed.

  The head control unit 132 drives the actuator unit 21 of the precoat head 2 based on the discharge data stored in the image data storage unit 131 to discharge precoat droplets from the discharge port 108 at a desired timing. By driving the actuator unit 21 of each inkjet head 1, a desired volume of ink droplets is ejected from the ejection port 108 at a desired timing.

  The first test pattern formation control unit 135 controls conveyance when an inspection signal for inspecting whether or not the precoat liquid is normally discharged from the discharge port 108 of the precoat head 2 is transferred from the PC or the like to the control unit 100. The section 130 is controlled to transport the paper P in the transport direction, and the head controller 132 is controlled to form a first test pattern 161 as shown in FIG. 6 on the transported paper P. The first test pattern formation control unit 135 simultaneously discharges the precoat liquid from the discharge ports 108 selected every three in order from one side in the main scanning direction of the precoat head 2 for each printing cycle via the head control unit 132. This is performed continuously for three printing cycles, and a continuous adhesion area 163 in which three adhesion areas (first liquid adhesion areas) 162 to which the precoat liquid has adhered is continuously formed along the transport direction is formed on the paper P. As a result, a plurality of continuous adhesion regions 163 are formed on the paper P in the main scanning direction. The continuous adhesion region 163 at this time is a one-dot region (attachment region 162) to which the precoat liquid ejected at an interval of 600 dpi (the same interval as 600 dpi, which is the main scanning direction resolution of the ejection port 108) is attached in the sub-scanning direction. It is a region formed by three consecutive parts along the transport direction. Then, the first test pattern formation control unit 135 moves the discharge port 108 of the precoat head 2 to the other one by one via the head control unit 132, while performing the previous discharge operation (discharge operation for forming the continuous adhesion region 163). ) Is repeated three times, and the precoat liquid is discharged from all the discharge ports 108. As a result, a continuous adhesion region 163 corresponding to the ejection port 108 adjacent in the main scanning direction is formed on the paper P in a state shifted in the transport direction. As described above, by forming the continuous adhesion regions 163 adjacent to each other in the main scanning direction at positions different from each other in the transport direction, it is possible to prevent the continuous adhesion regions 163 from contacting each other.

  Further, the first test pattern formation control unit 135 via the head control unit 132, on the paper P on which the adhesion region 162 is formed, the adhesion that is most downstream from the upstream end of the adhesion region 162 that is the most upstream in the transport direction. All of the black head 1 is discharged so that the black ink is discharged over the entire area between the downstream end of the region 162 and the outermost end of the two adhesion regions 162 that are outermost in the main scanning direction. Black ink is discharged from the discharge port 108. Specifically, the first test pattern formation control unit 135 indicates that black ink is simultaneously ejected from all the ejection ports 108 of the black head 1 every printing cycle via the head control unit 132 for 9 printing cycles. Do it continuously. Also in this case, the black ink is ejected at an interval of 600 dpi (the same interval as 600 dpi, which is the main scanning direction resolution of the ejection port 108) in the sub-scanning direction. As a result, all the continuous adhesion regions 163 and the non-adhesion region (first liquid non-adhesion region) 164 where the precoat liquid is not adhered unlike the continuous adhesion region 163 on the paper P on which the adhesion region 162 is formed. Black ink is ejected, and the first test pattern 161 is printed on the paper P. In the present embodiment, the non-adhesion region 164 is a collection of a plurality of ink adhesion regions 164a corresponding to the respective ejection openings 108 of the black head 1 and overlapping with the continuous adhesion region 163 along the transport direction, to which only black ink is adhered. The overall outer shape of the first test pattern 161 is a shape obtained by removing all the continuous adhesion regions 163 from the rectangular planar shape. The ink adhesion area 164a is composed of one dot area to which the ejected black ink is adhered, and is continuously arranged at least three or more in the transport direction.

  The second test pattern formation control unit 136 controls the head when an inspection signal for inspecting whether or not the precoat liquid is normally discharged from the discharge port 108 of the precoat head 2 is transferred from the PC or the like to the control unit 100. The control unit 132 controls the sheet P conveyed under the control of the first test pattern formation control unit 135 to a region other than the region where the first test pattern 161 is formed by the first test pattern formation control unit 135. Then, a second test pattern 171 as shown in FIG. 6 is formed. The second test pattern formation control unit 136 also simultaneously discharges the precoat liquid from the discharge ports 108 that are selected every three in order from the one in the main scanning direction of the precoat head 2 for each printing cycle via the head control unit 132. This is performed continuously for three printing cycles, and a continuous adhesion area 173 in which three adhesion areas (second liquid adhesion areas) 172 to which the precoat liquid adheres is continuous along the transport direction is formed on the paper P. As a result, a plurality of continuous adhesion regions 173 are formed on the paper P in the main scanning direction. The continuous adhesion area 173 at this time is also an area in which three 1-dot areas (adhesion areas 172) to which the precoat liquid ejected at an interval of 600 dpi is adhered in the sub-scanning direction are continuously arranged along the transport direction. Then, the second test pattern formation control unit 136 moves the discharge port 108 of the precoat head 2 to the other one by one via the head control unit 132, while performing the previous discharge operation (discharge operation for forming the continuous adhesion region 173). ) Is repeated three times, and the precoat liquid is discharged from all the discharge ports 108. As a result, a continuous adhesion region 173 corresponding to the ejection port 108 adjacent in the main scanning direction is formed on the paper P in a state shifted in the transport direction. As described above, the continuous adhesion regions 173 adjacent to each other in the main scanning direction are formed at different positions in the transport direction, so that the continuous adhesion regions 173 can be prevented from contacting each other.

  Further, the second test pattern formation control unit 136 via the head control unit 132, on the paper P on which the adhesion region 172 is formed, the adhesion that is most downstream from the upstream end of the adhesion region 172 that is the most upstream in the transport direction. The three color heads 1 are arranged such that composite black is formed on the entire surface between the downstream end of the region 172 and between the outermost ends of the two outermost attachment regions 172 in the main scanning direction. Color ink is discharged from all of the discharge ports 108. Specifically, the first test pattern formation control unit 135 performs 9 printings by simultaneously discharging the color ink from all the ejection ports 108 for each color head 1 for each printing cycle via the head control unit 132. Perform continuously. Also in this case, ink is ejected at an interval of 600 dpi in the sub-scanning direction. As a result, all the continuous adhesion regions 173 and the non-adhesion region (second liquid non-adhesion region) 174 where the precoat liquid is not adhered unlike the continuous adhesion region 173 on the paper P on which the adhesion region 172 is formed. Composite black is formed, and the second test pattern 171 is printed on the paper P. Also in this case, the non-adhesion area 174 overlaps with the continuous adhesion area 173 along the transport direction, and is composed of a plurality of ink adhesion areas 174a to which the composite black is adhered, and the entire outer shape thereof is the second test pattern. This is a shape obtained by removing all continuous adhesion regions 173 from the rectangular planar shape of 171. The ink adhesion area 174a is composed of one dot area to which composite black is adhered, and is continuously arranged at least three or more in the transport direction.

  Here, the composite black refers to a color formed by overlapping three color ink droplets on the paper P from the three color heads 1 other than the black head 1 that discharges black ink.

  In the present embodiment, the distance between the upstream end of the attachment regions 162 and 172 that are the most upstream in the transport direction and the downstream end of the attachment regions 162 and 172 that are the most downstream and the outermost 2 in the main scanning direction. Black ink and composite black are formed on the entire surface between the outermost ends of the two adhesion regions 162 and 172 to form the first and second test patterns 161 and 171. If black ink and composite black are formed on 172, the ink adhering areas 164a and 174a may be formed anywhere on the adhering areas 162 and 172 in the area where the precoat liquid shifted in the transport direction is not adhering. Good.

  The first calculation unit (concentration ratio calculation unit) 141 outputs the average density value of the three adhesion regions 162 belonging to the continuous adhesion region 163 output from the image sensor 30, and the three overlaps with the continuous adhesion region 163 along the transport direction. A first density ratio value, which is a ratio with the average density value of the ink adhesion region 164a, is calculated for all the ejection ports 108 of the precoat head 2. That is, the three ink adhesion regions 164a correspond to the respective ejection ports 108 in the same manner as the continuous adhesion regions 163 corresponding to the ejection ports 108. Therefore, in the first calculation unit 141, the average density value of the three adhesion regions 162 belonging to the continuous adhesion region 163 corresponding to one ejection port 108 and the average density of the three ink adhesion regions 164 a corresponding to the ejection port 108. The first density ratio value is calculated by the ratio to the value, and these are performed at all the ejection ports 108 of the precoat head 2.

  The second calculation unit (concentration ratio calculation means) 142 outputs an average density value of the three adhesion regions 172 belonging to the continuous adhesion region 173 output from the image sensor 30, and three overlaps with the continuous adhesion region 173 along the transport direction. A second density ratio value, which is a ratio to the average density value of the ink adhesion region 174a, is calculated for all the ejection ports 108 of the precoat head 2. Also in the second calculation unit 142, the calculation is performed for all the discharge ports 108 of the precoat head 2 in the same correspondence relationship as the first calculation unit 141.

  The third calculation unit (evaluation value calculation means) 143 is an evaluation value that is a ratio between the first concentration ratio value calculated by the first calculation unit 141 and the second concentration ratio value calculated by the second calculation unit 142. Is calculated for all the discharge ports 108 of the precoat head 2. The evaluation value for one ejection port 108 of the precoat head 2 at this time is calculated by the ratio of the first density ratio value and the second density ratio value for the ejection port 108, both of which have the same correspondence, and this is calculated as the precoat head. This is performed for all of the two discharge ports 108.

  The reference value storage unit 144 has a reference value as a reference for the evaluation value, and a size when the ink and the precoat liquid are ejected in three types of ejection amounts (small amount, medium amount, large amount) and land on the paper P. A plurality of size reference values serving as a reference are stored in advance.

  The precoat liquid discharge determination unit 145 determines whether the evaluation value calculated by the third calculation unit 143 is within a predetermined range centered on the reference value stored in the reference value storage unit 144. The determination is made for all the discharge ports 108. In addition, the predetermined range here refers to a range of ± 10% of the reference value, for example.

  The ink discharge determination unit 146 determines whether black ink has been discharged from all of the discharge ports 108 of the black head 1 based on the density value of the ink adhesion region 164a related to each discharge port 108 of the black head 1 output from the image sensor 30. Determine whether or not. Further, the ink discharge determination unit 146 determines the color ink from all the discharge ports 108 of the color head 1 based on the density value of the ink adhesion region 174a relating to each of the discharge ports 108 of the three color heads 1 output from the image sensor 30. Whether or not is discharged is determined. It should be noted that the determination of black ink and color ink ejection is performed based on the presence or absence of density values. The determination of whether or not the black ink and the color ink are ejected may be based on whether or not the ink density value in the ink adhesion region 174a is an appropriate value instead of the presence or absence of the density value.

    The droplet size determination unit 147 has a predetermined size centered on the size reference value stored in the reference value storage unit 144 so that the image size of the adhesion area 162 output from the image sensor 30 and relating to the ejection port 108 of the precoat head 2 is determined. Whether or not it is within the range is determined for all the ejection ports 108 of the precoat head 2. The predetermined size range here refers to, for example, a range of ± 10% of the reference value. In addition, the droplet size determination unit 147 is configured such that the image size of the ink adhesion region 164 a output from the image sensor 30 and relating to the ejection port 108 of the black head 1 is centered on the size reference value stored in the reference value storage unit 144. It is determined for all of the ejection ports 108 of the black head 1 whether or not it is within the predetermined range. In addition, the droplet size determination unit 147 outputs the image size of the ink adhesion region 174 a relating to each of the ejection openings 108 of the three color heads 1 output from the image sensor 30 to the size reference stored in the reference value storage unit 144. It is determined for all the ejection ports 108 of the color head 1 whether or not the value is within a predetermined range centered on the value. The determination of the image size at this time is a one-dot area when a single color ink, a mixed color ink in which each color ink is overlapped, and a synthetic ink in which the single color and the mixed color ink are overlapped with the precoat liquid land on the paper P. Is determined based on whether or not the width in the main scanning direction is within a size range centered on these reference size reference values. In order to make this determination, the data output from the image sensor 30 requires density value data with an interval smaller than the interval between the sensor elements adjacent in the main scanning direction (interval of 600 dpi). For example, in the case of density value data at an interval of 6000 dpi (4.23 μm), 10 density value data at different positions in the main scanning direction are obtained for each of the ink adhesion areas 164a and 174a and the continuous adhesion areas 163 and 173. It can be judged whether it is in the range of ± 10%. For example, assuming that the size reference value is a width (21.15 μm) corresponding to an interval of 3000 dpi, if the width in which the ink density can be detected is 16.92 to 25.38 μm, the size is determined to be within the size range.

  The purge control unit 151 performs a purge operation for discharging the ink in the ejection port 108 related to the inkjet head 1 and the precoat liquid in the ejection port 108 related to the precoat head 2 for at least one of the heads 1 and 2. As described above, the five pumps 32 are appropriately controlled. When the precoat liquid discharge determination unit 145 determines that the evaluation value of any of the discharge ports 108 of the precoat head 2 is not within the predetermined range, the purge control unit 151 receives the precoat liquid from the discharge ports 108 of the precoat head 2. Only the pump 32 related to the precoat head 2 is driven for a predetermined time so as to be discharged. Thereby, the precoat liquid in the discharge port 108 related to the precoat head 2 is discharged to the outside, and the discharge failure of the discharge port 108 is eliminated. In addition, when the ink discharge determination unit 146 determines that ink is not discharged from any of the discharge ports 108 of the inkjet head 1, the purge control unit 151 receives ink from the discharge port 108 of the specific inkjet head 1. Only the pump 32 related to the specific inkjet head 1 is driven for a predetermined time so that the ink is discharged. As a result, the ink in the ejection port 108 related to the inkjet head 1 is discharged to the outside, and the ejection failure of the ejection port 108 is eliminated. In addition, as shown in FIG. 7A, these purge operations are performed by ejecting ink and precoat liquid toward the conveyor belt 8 in a state where the inkjet head 1 and the precoat head 2 are arranged at the printing position. Done. Therefore, the discharged ink and precoat liquid are adhered on the transport belt 8.

  The head elevating control unit 152 controls the head elevating mechanism 33 so that the five heads 1 and 2 are moved from the printing position to the retracted position after the purge operation by the purge control unit 151 is completed. That is, as shown in FIG. 7B, when the purge operation is completed, the five heads 1 and 2 are arranged at the retracted position. In addition, the head lifting control unit 152 controls the head lifting mechanism 33 so that the five heads 1 and 2 are moved from the retracted position to the printing position after the wiping operation by the wiper control unit 153 described later is completed. That is, as shown in FIG. 7C, when the wiping operation is completed, the five heads 1 and 2 are arranged at the printing position.

  The wiper control unit 153 wipes the ejection surfaces of the inkjet head 1 and the precoat head 2 that have been purged by the purge control unit 151 after the head elevation control unit 152 moves the five heads 1 and 2 to the retracted position. The wiper unit 36 is controlled so as to be wiped off with the. As shown in FIG. 7B, the wiping operation at this time is performed mainly by the wiper control unit 153 while the wiper 36a is in contact with the ejection surfaces 1a and 2a of the inkjet head 1 and the precoat head 2 on which the purge operation has been performed. By controlling the wiper unit 36 so as to move along the scanning direction, the ejection surfaces 1a and 2a are wiped off.

  In the wiping operation, the cleaner control unit 154 starts the wiping of the discharge surface by the wiper unit 36, and simultaneously rotates the conveyance belt 8 counterclockwise via the conveyance control unit 50, and the cleaning liquid application member 37a and the blade 37b is moved to the contact position. Thus, a cleaning operation is performed in which the ink and precoat liquid discharged to the outer peripheral surface of the conveyor belt 8 are scraped off by the blade 37b together with the cleaning liquid applied to the cleaning liquid application member 37a.

  Next, an inspection method for inspecting the discharge state of the precoat liquid from each discharge port 108 of the precoat head 2 will be described. As shown in FIG. 8, the inkjet printer 101 first receives an inspection signal for inspecting whether or not the precoat liquid is normally discharged from the discharge port 108 of the precoat head 2 from a PC or the like (S1). When the inspection signal is received in step 1, in step 2 (S2), the first test pattern formation control unit 135 passes through the conveyance control unit 130 so that the paper P is conveyed along the conveyance path in the printer. The paper feed unit 101b, each feed roller pair 14, 28, and the transport mechanism 16 are controlled. At this time, the first test pattern formation control unit 135 controls the head control unit 132 so as to form the first test pattern 161 on the conveyed paper P. That is, the precoat liquid is discharged from all the discharge ports 108 of the precoat head 2 at a predetermined timing to form a plurality of continuous adhesion regions 163 on the paper P (first liquid adhesion region forming step), and all the continuous adhesion regions 163 are formed. Unlike the continuous adhesion region 163, black ink is ejected from all the ejection ports 108 of the black head 1 to the non-adhesion region 164 where the precoat liquid is not adhered at a predetermined timing, and the first test pattern 161 is formed. Form (first test pattern forming step).

  Further, at this time, the second test pattern formation control unit 136 forms the second test pattern 171 in an area on the same paper P on which the first test pattern 161 is formed and where the first test pattern 161 is not formed. The head controller 132 is controlled. That is, the precoat liquid is discharged from all the discharge ports 108 of the precoat head 2 at a predetermined timing to form a plurality of continuous adhesion regions 173 on the paper P (second liquid adhesion region forming step), and all the continuous adhesion regions 173 are formed. Unlike the continuous adhesion region 173, the second test pattern is obtained by ejecting color ink at a predetermined timing from all the ejection ports 108 of the three color heads 1 to the non-adhesion region 174 where the precoat liquid is not adhered. 171 is formed (S3: second test pattern forming step).

  Next, in step 4 (S4), the image sensor 30 detects the densities of both the test patterns 161 and 171 and outputs them to the control unit 100 (density detection process). At this time, the image sensor 30 detects the density and image size for each dot area of each test pattern, and outputs them to the control unit 100.

  Next, in step 5 (S5), the ink discharge determination unit 146 discharges black ink from all the discharge ports 108 of the black head 1 from the density value of the ink adhesion region 164a related to each discharge port 108 of the black head 1. Whether black ink has been ejected is determined. If black ink has been ejected, the process proceeds to step 6. If black ink has not been ejected, the process proceeds to step 14.

  Next, in step 6 (S6), the ink discharge determination unit 146 performs color from all the discharge ports 108 of the color head 1 based on the density values of the ink adhesion regions 174a related to the respective discharge ports 108 of the three color heads 1. It is determined whether or not ink has been ejected. If color ink has been ejected, the process proceeds to step 7, and if color ink has not been ejected, the process proceeds to step 14. In this case, whether or not color ink has been ejected from all the color heads 1 by creating an area where only each of the three color inks adheres to a part of the ink adhesion area 174a and detecting the density of this area. May be determined.

  Next, in step 7 (S7), the droplet size determination unit 147 determines the size reference value in which the image size of the ink adhesion region 164a associated with each ejection port 108 of the black head 1 is stored in the reference value storage unit 144. It is determined whether or not it is within a predetermined range centering on the center, and if it is within the predetermined range, the process proceeds to step 8;

  Next, in step 8 (S8), the droplet size determination unit 147 determines the image size of the ink adhesion region 174a associated with each ejection port 108 of the three color heads 1 as the size stored in the reference value storage unit 144. It is determined whether or not it is within a predetermined range centered on the reference value. If it is within the predetermined range, the process proceeds to step 9, and if not within the predetermined range, the process proceeds to step 14.

  Next, in step 9 (S9), the first calculation unit 141 causes the average density value of the three adhesion areas 162 belonging to the continuous adhesion area 163 and the three ink adhesion areas overlapping with the continuous adhesion area 163 along the transport direction. A first density ratio value, which is a ratio to the average density value of 164a, is calculated for all the ejection ports 108 of the precoat head 2 (first calculation step).

  Next, in step 10 (S10), the second calculation unit 142 causes the average density value of the three adhesion areas 172 belonging to the continuous adhesion area 173 and the three ink adhesion areas overlapping with the continuous adhesion area 173 along the transport direction. A second density ratio value, which is a ratio to the average density value of 174a, is calculated for all the ejection ports 108 of the precoat head 2 (second calculation step).

  Next, in step 11 (S11), the third calculation unit 143 uses an evaluation value that is a ratio of the first density ratio value and the second density ratio value related to the same ejection port 108 to all of the precoat heads 2. The discharge port 108 is calculated (third calculation step).

  Next, in step 12 (S12), the precoat liquid discharge determination unit 145 determines that the evaluation value related to each discharge port 108 of the precoat head 2 is within a predetermined range centered on the reference value stored in the reference value storage unit 144. If it is within the predetermined range, the process proceeds to step 13, and if not within the predetermined range, the process proceeds to step 14.

  Next, in step 13 (S13), the droplet size determination unit 147 determines that the image size of the adhesion region 162 related to each ejection port 108 of the precoat head 2 is centered on the size reference value stored in the reference value storage unit 144. If it is within the predetermined range, the process proceeds to step 16 (S16). If it is not within the predetermined range, the process proceeds to step 14.

  In step 14 (S14), the purge control unit 151 determines which of the four inkjet heads 1 and the precoat head 2 ejects the ink and the precoat liquid, and the ink from the desired head. Alternatively, the pump 32 is controlled so that the precoat liquid is discharged. That is, when the process proceeds from step 5 or step 7 to step 14, the purge control unit 151 drives only the pump 32 related to the black head 1 and discharges ink from the black head 1. When the process proceeds from step 6 or step 8 to step 14, the purge control unit 151 drives only the three pumps 32 related to the three color heads 1 and discharges ink from these color heads. When the process proceeds from step 12 or step 13 to step 14, the purge control unit 151 drives only the pump 32 related to the precoat head 2 and discharges the precoat liquid from the precoat head 2.

  Next, in step 15 (S15), the head lifting control unit 152 controls the head lifting mechanism 33 to move the five heads 1 and 2 from the printing position to the retracted position. And the wiper control part 153 controls the wiper unit 36, and wipes only the discharge surfaces 1a and 2a which performed the purge operation with the wiper 36a. In this way, the ink and precoat liquid adhering to the ejection surfaces 1a and 2a can be removed. Thereafter, the head lifting control unit 152 controls the head lifting mechanism 33 to move the five heads 1 and 2 to a position slightly lifted from the retracted position, and the wiper control unit 153 controls the wiper unit 36. The wiper 36a is returned to the original position. Thereby, the wiper 36a can be returned to the original position without being brought into contact with the ejection surfaces 1a and 2a. When the wiper 36a returns to the original position, the head lifting control unit 152 controls the head lifting mechanism 33 to move the five heads 1 and 2 to the printing position.

  At this time, the cleaner control unit 154 starts the wiping operation and simultaneously rotates the conveyance belt 8 counterclockwise via the conveyance control unit 50 and makes the cleaning liquid application member 37a and the blade 37b contact each other. Move to position. Thus, a cleaning operation is performed in which the ink and precoat liquid discharged to the outer peripheral surface of the conveyor belt 8 are scraped off by the blade 37b together with the cleaning liquid applied to the cleaning liquid application member 37a. When the five heads 1 and 2 are returned to the printing position, the cleaner control unit 154 stops the rotation of the conveyance belt 8 via the conveyance control unit 50 and applies the cleaning liquid application member 37a and the blade 37b. Move from contact position to remote position. Thus, when the processing in step 15 is completed, the process returns to step 2, and when a test pattern is printed again on a new sheet P and finally proceeds to step 16, the discharge from all the discharge ports 108 of the precoat head 2 is performed. The state check ends. In this way, it is possible to determine whether printing is possible.

  As described above, according to the inkjet printer 101 of the present embodiment, in step 12, the first density ratio value, which is the ratio between the density value of the precoat liquid + black ink and the density value of the black ink, and the precoat liquid + composite black ink. It is determined whether or not an evaluation value that is a ratio of the second density ratio value that is a ratio of the density value of the composite black ink and the density value of the composite black ink is within a predetermined range.

  Specifically, when the detection is performed when the image sensor 30 is not deteriorated, if the density value of the precoat liquid + black ink is 300 and the density value of the black ink is 100, the first density ratio value is tripled. If the density value of the precoat liquid + composite black ink is 160 and the density value of the composite black ink is 80, the second density ratio value is doubled. Then, the evaluation value, which is the ratio between the first concentration ratio value and the second concentration ratio value, is 1.5 times, and it is determined whether this is within a predetermined range. On the other hand, when the image sensor 30 deteriorates and the amount of received light detected decreases, if the density value of the precoat liquid + black ink is 240 and the density value of the black ink is 80, the first density ratio value is tripled. If the density value of the precoat liquid + composite black ink is 128 and the density value of the composite black ink is 64, the second density ratio value is doubled. The evaluation value, which is the ratio between the first density ratio value and the second density ratio value, is 1.5 times, and the evaluation value is not affected by the deterioration of the image sensor 30.

  Further, when there is no variation in the precoat liquid and ink absorption of the paper P, if the density value of the precoat liquid + black ink is 300 and the density value of the black ink is 100, the first density ratio value is tripled. If the density value of the precoat liquid + composite black ink is 160 and the density value of the composite black ink is 80, the second density ratio value is doubled. The evaluation value, which is the ratio between the first concentration ratio value and the second concentration ratio value, is 1.5 times. On the other hand, when the paper P is uneven, the first density ratio value is tripled when the density value of the precoat liquid + black ink is 210 and the density value of the black ink is 70. If the density value of the precoat liquid + composite black ink is 112 and the density value of the composite black ink is 56, the second density ratio value is doubled. The evaluation value, which is the ratio between the first density ratio value and the second density ratio value, is 1.5 times, and the evaluation value is not affected by variations in the paper P.

  Further, when the viscosity of the precoat liquid itself is not deteriorated, if the density value of the precoat liquid + black ink is 300 and the density value of the black ink is 100, the first density ratio value is tripled. If the density value of the precoat liquid + composite black ink is 160 and the density value of the composite black ink is 80, the second density ratio value is doubled. The evaluation value, which is the ratio between the first concentration ratio value and the second concentration ratio value, is 1.5 times. On the other hand, when the viscosity of the precoat liquid itself is deteriorated, if the density value of the precoat liquid + black ink is 180 and the density value of the black ink is 100, the first density ratio value is 1.8 times. If the density value of the precoat liquid + composite black ink is 96 and the density value of the composite black ink is 80, the second density ratio value is 1.2 times. The evaluation value, which is the ratio between the first concentration ratio value and the second concentration ratio value, is 1.5 times, and the evaluation value is not affected by the deterioration of the viscosity of the precoat liquid. In addition, even when the color of the ink itself deteriorates, it is not affected as in the case of these evaluation values. As described above, even if a detection error occurs in the image sensor 30 that detects the density of each test pattern 161 and 171, the precoat liquid and the ink absorption vary on the same type of paper P, and further the viscosity of the precoat liquid itself. Even if the aging deterioration of the ink and the color development of the ink occur, the calculated evaluation value does not change due to these influences. Therefore, the quality of the discharge state from all the discharge ports 108 of the precoat head 2 is accurately determined. Is possible.

  In addition, since the ink color forming the first test pattern 161 is black and the ink color forming the second test pattern 171 is composite black, the density difference detected by the image sensor 30 increases. This is because the precoating liquid aggregation or precipitation tends to become more prominent as the ink density (lightness) is higher (lower). Therefore, it is possible to calculate the first concentration ratio value and the second concentration ratio value with high accuracy. For this reason, the accuracy of the evaluation value is also improved.

  In addition, since the control unit 100 includes the ink ejection determination unit 146, the ejection state of the ejection port 108 of the inkjet head 1 that ejects ink to form the first and second test patterns 161 and 171 is also determined. Can be determined. In addition, since it is possible to determine the quality of the ejection state of the inkjet head 1, the reliability of the quality determination of the ejection state from the ejection port 108 of the precoat head 2 is improved.

  In addition, since the first calculation unit 141 and the second calculation unit 142 calculate the first and second density ratio values from the average density value, the accuracy of the evaluation value is improved. Therefore, it is possible to determine the quality of the discharge state from the discharge port 108 of the precoat head 2 with higher accuracy.

  Further, since the precoat liquid discharge determination unit 145 determines all the discharge ports 108 of the precoat head 2, it is possible to determine whether printing is possible.

  As a modification, the control unit 100 changes the reference value stored in the reference value storage unit 144 to the evaluation value calculated by the third calculation unit 143 after the determination by the precoat liquid discharge determination unit 145 is performed. You may have a reference value change part (reference value change means). Thus, after the determination by the precoat liquid discharge determination unit 145 is made, the evaluation value calculated by the third calculation unit 143 can be changed to the reference value stored in the reference value storage unit 144. For this reason, by changing the reference value so as to follow various changes, the precoat liquid discharge determination unit 145 can perform determination with high robustness.

  Further, since the first and second test patterns 161 and 171 are formed on the same paper P, the paper P can be saved. As another modification, the first test pattern 161 and the second test pattern 171 may be formed on different paper P.

  Next, the ink jet printer according to the second embodiment will be described below with reference to FIGS. 9 and 10. The ink jet printer according to the present embodiment is the same as the first embodiment except that the configuration of the control unit 200 is slightly different. Accordingly, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The control unit 200 of the ink jet printer in the present embodiment replaces the first and second test pattern formation control units 135 and 136 of the control unit 100 in the first embodiment, and controls the head selection unit 233 and the pre-ink adhesion region formation control. Only the part 235 and the ink adhesion area formation control part 236 are provided, and the other parts are the same as those in the first embodiment. The head selection unit 233 selects one of the four inkjet heads 1 to eject ink when an inspection signal is transferred from the PC or the like to the control unit 200.

  When the inspection signal is transferred from the PC or the like to the control unit 100, the pre-ink adhesion region formation control unit 235 controls the conveyance control unit 130 to convey the paper P in the conveyance direction, and from the precoat head 2 to the precoat. The head controller 132 is controlled such that the liquid is ejected from the head 1 selected by the head selector 233, and a plurality of continuous adhesion regions 163 and 173 as shown in FIG. Form. The pre-ink adhesion region formation control unit 235 simultaneously outputs the pre-coating liquid from the ejection ports 108 that are selected every three in order from the one in the main scanning direction of the pre-coating head 2 for each printing cycle via the head control unit 132. Discharging is performed continuously for three printing cycles, and a continuous adhesion area 163 in which three adhesion areas (first liquid adhesion areas) 162 to which the precoat liquid adheres is continuous along the transport direction is formed on the paper P. . As a result, a plurality of continuous adhesion regions 163 are formed on the paper P in the main scanning direction. Then, the pre-ink adhesion region formation control unit 235 moves the ejection port 108 of the precoat head 2 to the other one by one via the head control unit 132, while performing the previous ejection operation (the ejection that forms the continuous adhesion region 163). The operation) is repeated three times, and the precoat liquid is discharged from all the discharge ports 108. As a result, a continuous adhesion region 163 corresponding to the ejection port 108 adjacent in the main scanning direction is formed on the paper P in a state shifted in the transport direction. Further, the pre-ink adhesion region formation control unit 235 performs the same control as described above, and a plurality of continuous adhesion regions 173 in which three adhesion regions (second liquid adhesion regions) 172 are continuously arranged in the transport direction. Are formed in the same pattern as the continuous adhesion region 163 in a region away from the region in which the plurality of continuous adhesion regions 163 are formed in the transport direction.

  Further, the pre-ink adhesion region formation control unit 235 passes the head for black (first identification) via the head control unit 132 so as to form the first pre-ink adhesion region where the black ink is adhered on the continuous adhesion region 163. Ink discharge head 1 is controlled. The pre-ink adhesion area formation control unit 235 has three color heads (first inks) via the head control unit 132 so as to form a second pre-ink adhesion area where the composite black ink is adhered on the continuous adhesion area 173. (2) specific ink ejection head) 1 is controlled.

  When the inspection signal is transferred from the PC or the like to the control unit 100, the ink adhesion region formation control unit 236 controls the conveyance control unit 130 to convey the paper P in the conveyance direction and is selected by the head selection unit 233. The head controller 132 is controlled so that ink is discharged from the head 1, and a plurality of ink adhesion regions 164 a and 174 a as shown in FIG. 6 are formed on the conveyed paper P. Specifically, the ink adhesion area formation control unit 236 is arranged between the upstream end of the adhesion area 162 that is the most upstream in the transport direction and the downstream end of the adhesion area 162 that is the most downstream and the outermost area in the main scanning direction. The black head (first specific ink) is formed so that the ink adhering area 164a is formed at a position that does not overlap all the continuous adhering areas 163 in the rectangular planar shape between the outermost ends of two adhering areas 162. The discharge head 1 is controlled. Further, the ink adhesion area formation control unit 236 has two outermost areas with respect to the main scanning direction between the upstream end of the adhesion area 172 upstream of the conveyance direction and the downstream end of the adhesion area 172 downstream of the main scanning direction. Three color heads (second specific ink ejection) are formed so that the ink adhesion area 174a is formed at a position that does not overlap all the continuous adhesion areas 173 in the rectangular planar shape between the outermost ends of the adhesion areas 172. Head) 1 is controlled.

  Next, an inspection method for inspecting the discharge state of the precoat liquid from each discharge port 108 of the precoat head 2 will be described. As shown in FIG. 10, the inkjet printer 101 first receives an inspection signal from a PC or the like (F1), as in the first embodiment. When the inspection signal is received in step 1, in step 2 (F2), the head selection unit 233 selects which of the four heads 1 ejects ink (head selection process). Specifically, in step 3 to be described later, the black head (first specific ink discharge head) 1 is selected. In step 4 described later, three color heads (second specific ink ejection heads) 1 are selected.

  Next, in step 3 (F3), the pre-ink adhesion region formation control unit 235 causes the paper feed unit 101b, the conveyance unit 130b, and the paper P to be conveyed along the conveyance path in the printer. Each feed roller pair 14, 28 and the transport mechanism 16 are controlled. At this time, the pre-ink adhesion region formation control unit 235 controls the head control unit 132 so as to form a plurality of first pre-ink adhesion regions on the conveyed paper P. That is, the precoat liquid is discharged from all the discharge ports 108 of the precoat head 2 at a predetermined timing to form a plurality of continuous adhesion regions 163 on the paper P, and all the discharges of the black head 1 are discharged to all the continuous adhesion regions 163. Black ink is ejected from the outlet 108 at a predetermined timing to form a plurality of first pre-ink adhesion areas (first liquid ink adhesion area forming step). At this time, the ink adhesion region formation control unit 236 controls the head control unit 132 so as to form a plurality of ink adhesion regions 164a on the conveyed paper P (first ink adhesion region formation step). . Thus, the first test pattern 161 is printed on the paper P.

  Next, in step 4 (F4), the pre-ink adhesion area formation control unit 235 controls the head so as to form a plurality of second pre-ink adhesion areas on the paper P on which the first test pattern 161 is formed. The unit 132 is controlled. That is, the precoat liquid is discharged from all the discharge ports 108 of the precoat head 2 at a predetermined timing to form a plurality of continuous adhesion regions 173 on the paper P, and all of the three color heads 1 are formed in all the continuous adhesion regions 173. The color ink is ejected from the ejection port 108 at a predetermined timing to form a plurality of second pre-ink adhesion regions (second liquid ink adhesion region forming step). At this time, the ink adhesion region formation control unit 236 controls the head control unit 132 so as to form a plurality of ink adhesion regions 174a on the conveyed paper P (second ink adhesion region formation step). Thus, the second test pattern 171 is printed on the paper P.

  In the present embodiment, the first test pattern 161 is printed in Step 3, but only the first pre-ink adhesion area may be formed on the paper P first. In a later step, black ink may be ejected onto this region to form the ink adhesion region 164a. Furthermore, although the second test pattern 171 is printed in step 4, it is sufficient to form only the second pre-ink adhesion area and form the ink adhesion area 174a in the subsequent steps. In these cases, the first pre-ink adhesion area, the second pre-ink adhesion area, the ink adhesion area 164a, and the ink adhesion area 174a may be formed on the paper P in this order. In other words, these four regions may be formed in any order, and may be formed on the same type of paper P different from each other.

  Next, Step 5 (F5) to Step 17 (F17) similar to Step 4 to Step 16 of the first embodiment are performed, and the inspection of the ejection state of the precoat head 2 is completed.

  As described above, also in the ink jet printer of this embodiment, the first density ratio value, which is the ratio between the density value of the precoat liquid + black ink and the density value of the black ink, the density value of the precoat liquid + composite black ink, and the composite It is determined whether an evaluation value that is a ratio with the second density ratio value that is a ratio with the density value of the black ink is within a predetermined range. For this reason, as in the first embodiment, it is possible to accurately determine the quality of the discharge state from all the discharge ports 108 of the precoat head 2.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. For example, in each of the above-described embodiments, the evaluation value is calculated for all the ejection ports 108 of the precoat head 2, but the evaluation value for only one of the ejection ports 108 is calculated, and the evaluation value is predetermined. You may determine whether it is in the range. The ink colors constituting the first test pattern 161 and the second test pattern 171 may be any ink color as long as they are different from each other. However, it is preferable to use one having low brightness. This is because as the ink density (lightness) is higher (lower), the pre-coating liquid tends to agglomerate or precipitate, and the density difference detected by the image sensor 30 becomes larger. Accuracy is improved. Further, the first and second density ratio values may not be calculated from the average density value. Further, in each of the above-described embodiments, the three color heads 1 are configured to eject ink droplets of different colors, but the two color heads 1 or four or more color heads 1 have different color inks. It may be configured to eject droplets. The present invention is also applicable to a liquid ejecting apparatus that ejects liquid other than ink. Further, the present invention is not limited to a printer, and can be applied to a facsimile, a copier, and the like.

  In each of the above-described embodiments, one ink jet printer is provided with the control units 100 and 200, the image sensor 30, and the like to form one liquid ejection device. For example, the control units 100 and 200 The first calculation unit 141, the second calculation unit 142, the third calculation unit 143, the reference value storage unit 144, the precoat liquid discharge determination unit 145, the ink discharge determination unit 146, and the like are provided in the PC, and the PC is replaced with the image sensor 30. A scanner that is connected to and capable of detecting the density of an image may be used. In this case, the printer, the PC, and the scanner constitute one liquid ejecting apparatus, and the same effects as the printers (liquid ejecting apparatuses) of the first and second embodiments can be obtained. In each of the above-described embodiments, the precoat liquid discharge determination unit 145 performs the purge operation and the wiping operation when the evaluation value is not within the predetermined range. However, these operations are not particularly required. . In this case, it is only necessary to store which ejection port 108 of the precoat head 2 is not within the predetermined range and notify the user of the presence of the defective ejection port 108. Then, a purge operation or a wiping operation may be performed according to an instruction from the user.

  Further, in each of the above-described embodiments, whether or not the evaluation value calculated by the precoat liquid discharge determination unit 145 is within a range of ± 10% centered on the reference value stored in the reference value storage unit 144. However, the predetermined range is appropriately set to a range that does not hinder image recording, and may not be ± 10%.

  In each of the above-described embodiments, the ink discharge determination unit 146 determines whether or not ink is discharged from the discharge port 108 (S5 and S6 in FIG. 8, F6 and F7 in FIG. 10), and the droplet size. The determination unit 147 determines whether or not the image size is within a predetermined size range centered on the reference value (S7, S8, S13 in FIG. 8, F8, F9, F14 in FIG. 10). It is not necessary to judge. In that case, only the determination of the precoat liquid discharge determination unit 145 (S12 in FIG. 8, F13 in FIG. 10) is performed. If the evaluation value does not fall within the predetermined range, the purge operation is performed on both the precoat head 2 and the inkjet head 1. (S14 in FIG. 8 and F15 in FIG. 10).

  In each of the above-described embodiments, each head 1 and 2 is provided with ejection energy by the actuator unit 21. As the means for imparting ejection energy, in addition to the piezoelectric type, an electrostatic type actuator or a thermal type is used. There may be provided discharge energy generating means such as a heating element.

1 Inkjet head (first ejection head)
2 Precoat head (second discharge head)
16 Conveyance mechanism 30 Image sensor (density detection means)
101 Inkjet printer (liquid ejection device)
108 Discharge port (first and second discharge ports)
135 1st test pattern formation control part (1st test pattern formation control means)
136 2nd test pattern formation control part (2nd test pattern formation control means)
141 1st calculation part (1st calculation means: concentration ratio calculation means)
142 2nd calculation part (2nd calculation means: concentration ratio calculation means)
143 3rd calculation part (3rd calculation means: evaluation value calculation means)
144 Reference value storage unit (reference storage means)
145 Precoat liquid discharge determination unit (determination means)
146 Ink discharge determination unit (preliminary determination means)
162 Adhesion area (first liquid adhesion area)
164 Non-adhesion area (first liquid non-adhesion area)
172 Adhesion area (second liquid adhesion area)
174 Non-adhesion area (second liquid non-adhesion area)
233 Head selection unit (selection means)
235 Pre-ink adhesion area formation control unit (liquid ink adhesion area formation control means)
236 Ink Adhesion Area Formation Control Unit (Ink Adhesion Area Formation Control Unit)

Claims (11)

A transport mechanism for transporting the recording medium in the transport direction;
A plurality of first ejection openings for ejecting ink onto a recording medium arranged at equal intervals in a direction orthogonal to the transport direction, and ejecting inks of different colors arranged along the transport direction; A plurality of first ejection heads;
A plurality of second discharge ports for discharging a liquid that is arranged at the same interval as the first discharge ports in the orthogonal direction and acts on the ink to aggregate or deposit components in the ink onto a recording medium; A second ejection head disposed upstream of the first ejection head in the transport direction;
The liquid is ejected from at least one second ejection port of the plurality of second ejection ports toward the recording medium to form a first liquid adhesion region, and the first liquid adhesion region and the first liquid are formed. One or more in the first liquid non-adhesion area, which is an area different from the first liquid adhesion area on the same recording medium as the recording medium on which the adhesion area is formed, and where the liquid does not adhere to the recording medium. First test pattern formation control for controlling one or more of the first ejection heads and the second ejection heads so that ink is ejected from the first ejection ports of the first ejection heads to form a first test pattern. Means,
A recording medium on which the liquid is discharged from the at least one second discharge port toward the recording medium to form a second liquid adhesion area, and the second liquid adhesion area and the second liquid adhesion area are formed; Ejected when forming the first test pattern in a second liquid non-adhering area, which is an area different from the second liquid adhering area on the same recording medium and where the liquid is not adhering to the recording medium. One or more of the first ejection heads and the second ejection so as to form a second test pattern by ejecting ink from the first ejection ports of one or more of the first ejection heads other than the first ejection head. Second test pattern formation control means for controlling the head;
Density detecting means for detecting the density of the first and second test patterns;
First calculation means for calculating a first concentration ratio value, which is a ratio of density values of the first liquid adhesion area and the first liquid non-adhesion area, based on the density of the first test pattern detected by the density detection means; ,
Second calculation means for calculating a second concentration ratio value, which is a ratio of density values of the second liquid adhesion area and the second liquid non-adhesion area, based on the density of the second test pattern detected by the density detection means; ,
Third calculation means for calculating an evaluation value that is a ratio between the first concentration ratio value calculated by the first calculation means and the second concentration ratio value calculated by the second calculation means;
Reference storage means for storing a reference value of the evaluation value;
Determining means for determining whether or not the evaluation value calculated by the three calculating means is within a predetermined range centered on the reference value stored in the reference storage means; Liquid ejecting device. The plurality of first discharge heads are composed of four or more discharge heads that discharge black ink, inks of colors other than black and different colors,
The first test pattern formation control unit is configured to discharge black ink from the first discharge head to the first liquid adhesion region and the first liquid non-adhesion region. Controlling the first ejection head for ejecting a black ink;
The second test pattern formation control means ejects different color inks from the three first ejection heads to the second liquid adhesion region and the second liquid non-adhesion region, The color inks of the four first ejection heads are formed so that a composite black composed of three color ink droplets overlapping on the recording medium is formed in the second liquid non-adhering region. The liquid discharge apparatus according to claim 1, wherein the three first discharge heads that respectively discharge the liquid are controlled.   The one or more first ejection heads that eject ink to form the first and second test patterns based on the concentrations of the first and second liquid non-adhering regions detected by the concentration detection unit. The liquid ejecting apparatus according to claim 1, further comprising preliminary determination means for determining whether or not ink is ejected from the first ejection port. The first test pattern formation control means includes at least one so that a plurality of the first liquid adhering regions and the first liquid non-adhering regions corresponding to the one second discharge port are formed along the transport direction. Controlling the first discharge head and the second discharge head,
The second test pattern formation control means includes at least one so that a plurality of the second liquid adhesion region and the second liquid non-adhesion region corresponding to the one second ejection port are formed along the transport direction. Controlling the first discharge head and the second discharge head,
The first calculation means includes an average concentration value obtained by averaging the concentrations of the plurality of first liquid adhesion regions that overlap each other along the transport direction, and a plurality of the first liquid non-stacks that overlap each other along the transport direction. The first concentration ratio value is calculated by a ratio with an average concentration value obtained by averaging the concentration of the adhesion region,
The second calculation means includes an average concentration value obtained by averaging the concentrations of the plurality of second liquid adhesion regions that overlap each other along the transport direction, and a plurality of the second liquid non-stacks that overlap each other along the transport direction. The liquid ejection apparatus according to claim 1, wherein the second density ratio value is calculated by a ratio with an average density value obtained by averaging the density of the adhesion region.   5. The liquid ejection apparatus according to claim 1, wherein the formation of the first and second test patterns and the determination by the determination unit are performed at all of the plurality of second ejection ports. 6.   After the determination by the determination means, the apparatus further comprises reference value changing means for changing the reference value stored in the reference storage means to the evaluation value calculated by the third calculation means. The liquid ejection apparatus according to claim 1, wherein the liquid ejection apparatus is a liquid ejection apparatus.   The liquid ejection apparatus according to claim 1, wherein the first test pattern and the second test pattern are formed on the same recording medium. A transport mechanism for transporting the recording medium in the transport direction; and a plurality of first ejection ports for ejecting ink to the recording medium arranged at equal intervals in a direction orthogonal to the transport direction, along the transport direction And a plurality of first ejection heads that eject inks of different colors and are arranged at the same intervals as the first ejection ports in the orthogonal direction to cause the components in the ink to aggregate or deposit. A second ejection head having a plurality of second ejection ports for ejecting liquid onto the recording medium and disposed upstream of the first ejection head in the transport direction; and a density for detecting a density on the recording medium In the inspection method of the liquid ejection apparatus having the detection means,
A first liquid adhesion region forming step of ejecting the liquid from at least one of the plurality of second ejection ports toward the recording medium to form a first liquid adhesion region;
An area different from the first liquid adhesion area on the same recording medium as the recording medium on which the first liquid adhesion area and the first liquid adhesion area are formed, and the liquid is not adhered to the recording medium. A first test pattern forming step of forming a first test pattern by discharging ink from the first discharge ports of one or more of the first discharge heads to a certain first liquid non-adhering region;
A second liquid adhesion region forming step of forming a second liquid adhesion region by ejecting the liquid from the at least one second ejection port toward the recording medium;
An area that is different from the second liquid adhesion area on the same recording medium as the recording medium on which the second liquid adhesion area and the second liquid adhesion area are formed, and in which the liquid does not adhere to the recording medium. A second test is performed by ejecting ink from the first ejection ports of one or more first ejection heads other than the first ejection head ejected when the first test pattern is formed in a second liquid non-adhering region. A second test pattern forming step of forming a pattern;
A density detection step of detecting density of the first and second test patterns formed on the recording medium by the density detection means;
In the concentration detection step, the concentration of the first test pattern is detected by the concentration detection means, whereby a first concentration ratio value that is a ratio of the concentration values of the first liquid adhesion region and the first liquid non-adhesion region. A first calculation step of calculating
In the concentration detection step, the concentration of the second test pattern is detected by the concentration detection means, whereby a second concentration ratio value that is a ratio of the concentration values of the second liquid adhesion region and the second liquid non-adhesion region. A second calculation step of calculating
A third calculation step of calculating an evaluation value that is a ratio between the first concentration ratio value calculated in the first calculation step and the second concentration ratio value calculated in the second calculation step;
And a determination step of determining whether or not the evaluation value calculated in the third calculation step is within a predetermined range centered on the stored reference value. Inspection method. A transport mechanism for transporting the recording medium in the transport direction; and a plurality of first ejection ports for ejecting ink to the recording medium arranged at equal intervals in a direction orthogonal to the transport direction, along the transport direction And a plurality of first ejection heads that eject inks of different colors and are arranged at the same intervals as the first ejection ports in the orthogonal direction to cause the components in the ink to aggregate or deposit. A second ejection head having a plurality of second ejection ports for ejecting liquid onto the recording medium and disposed upstream of the first ejection head in the transport direction; and a density for detecting a density on the recording medium A computer for controlling a liquid ejection apparatus having a detection unit;
The liquid is ejected from at least one second ejection port of the plurality of second ejection ports toward the recording medium to form a first liquid adhesion region, and the first liquid adhesion region and the first liquid are formed. One or more in the first liquid non-adhesion area, which is an area different from the first liquid adhesion area on the same recording medium as the recording medium on which the adhesion area is formed, and where the liquid does not adhere to the recording medium. First test pattern formation control for controlling one or more of the first ejection heads and the second ejection heads so that ink is ejected from the first ejection ports of the first ejection heads to form a first test pattern. means,
A recording medium on which the liquid is discharged from the at least one second discharge port toward the recording medium to form a second liquid adhesion area, and the second liquid adhesion area and the second liquid adhesion area are formed; Ejected when forming the first test pattern in a second liquid non-adhering area, which is an area different from the second liquid adhering area on the same recording medium and where the liquid is not adhering to the recording medium. One or more of the first ejection heads and the second ejection so as to form a second test pattern by ejecting ink from the first ejection ports of one or more of the first ejection heads other than the first ejection head. Second test pattern formation control means for controlling the head;
A first calculation for calculating a first concentration ratio value, which is a ratio of the density values of the first liquid adhering region and the first liquid non-adhering region, by causing the concentration detecting unit to detect the concentration of the first test pattern. means,
A second calculation for calculating a second concentration ratio value, which is a ratio of the concentration values of the second liquid adhering region and the second liquid non-adhering region, by causing the concentration detecting unit to detect the concentration of the second test pattern. means,
Third calculation means for calculating an evaluation value that is a ratio between the first concentration ratio value calculated by the first calculation means and the second concentration ratio value calculated by the second calculation means;
Reference storage means for storing a reference value of the evaluation value; and
The evaluation value calculated by the three calculation means functions as a determination means for determining whether or not the evaluation value is within a predetermined range centered on the reference value stored in the reference storage means. program. A transport mechanism for transporting the recording medium in the transport direction;
A plurality of first ejection openings for ejecting ink onto a recording medium arranged at equal intervals in a direction orthogonal to the transport direction, and ejecting inks of different colors arranged along the transport direction; A plurality of first ejection heads;
A plurality of second discharge ports for discharging a liquid that is arranged at the same interval as the first discharge ports in the orthogonal direction and acts on the ink to aggregate or deposit components in the ink onto a recording medium; A second ejection head disposed upstream of the first ejection head in the transport direction;
Selection means for selecting one or more first specific ink discharge heads that are the first discharge heads and one or more second specific ink discharge heads that are the first discharge heads other than the first specific ink discharge heads;
A liquid that controls the first and second specific ink ejection heads, the second ejection head, and the transport mechanism to form a liquid ink adhesion area that is an area where both the ink and the liquid are adhered on a recording medium. An ink adhesion region formation control means;
An ink adhesion area formation control means for controlling the first and second specific ink ejection heads and the transport mechanism to form an ink adhesion area which is an area where only the ink is adhered on a recording medium;
Density detecting means for detecting the density of the liquid ink adhesion area and the ink adhesion area;
Density ratio calculation means for calculating a density ratio value, which is a ratio of the density of the liquid ink adhesion area and the ink adhesion area, from the density of the liquid ink adhesion area and the ink adhesion area detected by the density detection means;
Evaluation value calculating means for calculating an evaluation value that is a ratio of two different concentration ratio values calculated by the concentration ratio calculating means;
Reference storage means for storing a reference value of the evaluation value;
A liquid ejecting apparatus including: a determination unit that determines whether the evaluation value calculated by the evaluation value calculation unit is within a predetermined range centered on the reference value stored in the reference storage unit; ,
The selection means selects the first and second specific ink ejection heads;
With respect to one or a plurality of recording media, the liquid ink adhesion region formation control means is configured such that at least one second ejection port out of the plurality of second ejection ports is any one of the one or more recording media. The first liquid ink is ejected from the first ejection port of the first specific ink ejection head to form a first liquid adhesion area by ejecting the liquid toward the first liquid deposition area. An adhesion region is formed, and the liquid is ejected from the at least one second ejection port toward any one of the one or a plurality of recording media to form a second liquid adhesion region. In addition, the second liquid ink adhesion region is formed by ejecting ink from the first ejection port of the second specific ink ejection head to the second liquid adhesion region,
The ink adhesion region formation control means discharges ink from the first discharge port of the first specific ink discharge head toward any one of the one or a plurality of recording media to thereby form a first An ink adhering region is formed, and ink is ejected from the first ejection port of the second specific ink ejection head toward any one of the one or the plurality of recording media. Forming an ink adhesion area,
The density detection means detects the density of the first and second liquid ink adhesion areas and the density of the first and second ink adhesion areas;
The density ratio calculating means has a first density ratio value that is a ratio of density values of the first liquid ink adhesion area and the first ink adhesion area detected by the density detection means, and the second liquid. Calculating a second density ratio value which is a ratio of density values of the ink adhesion area and the second ink adhesion area;
The evaluation value calculating means calculates the evaluation value relating to a ratio between the first concentration ratio value and the second concentration ratio value;
The determination means determines whether or not the evaluation value relating to the ratio between the first concentration ratio value and the second concentration ratio value is within a predetermined range centered on the reference value. Discharge device. A transport mechanism for transporting the recording medium in the transport direction;
A plurality of first ejection openings for ejecting ink onto a recording medium arranged at equal intervals in a direction orthogonal to the transport direction, and ejecting inks of different colors arranged along the transport direction; A plurality of first ejection heads;
A plurality of second discharge ports for discharging a liquid that is arranged at the same interval as the first discharge ports in the orthogonal direction and acts on the ink to aggregate or deposit components in the ink onto a recording medium; A second ejection head disposed upstream of the first ejection head in the transport direction;
A liquid ink adhesion area that controls the plurality of first ejection heads, the second ejection heads, and the transport mechanism to form a liquid ink adhesion area that is an area where both the ink and the liquid are adhered on a recording medium. Formation control means;
Inspection of a liquid ejection apparatus comprising: an ink adhesion area formation control unit that controls the plurality of first ejection heads and the transport mechanism to form an ink adhesion area that is an area where only the ink is adhered on a recording medium. In the method
A head selecting step of selecting one or more first specific ink discharge heads that are the first discharge heads and one or more second specific ink discharge heads that are the first discharge heads other than the first specific ink discharge heads;
With respect to one or a plurality of recording media, the liquid ink adhesion region formation control means is configured such that at least one second ejection port out of the plurality of second ejection ports is any one of the one or more recording media. The first liquid ink is ejected from the first ejection port of the first specific ink ejection head to form a first liquid adhesion area by ejecting the liquid toward the first liquid deposition area. A first liquid ink adhesion region forming step for forming the adhesion region;
The liquid ink adhesion region formation control means causes the liquid to be ejected from the at least one second ejection port toward any one of the one or a plurality of recording media to thereby form a second liquid adhesion region. And a second liquid ink adhesion region forming step of forming a second liquid ink adhesion region by ejecting ink from the first ejection port of the second specific ink ejection head to the second liquid adhesion region. ,
The ink adhering area forming system discharges ink from the first discharge port of the first specific ink discharge head toward any one of the one or the plurality of recording media to thereby generate the first ink. A first ink adhesion region forming step for forming the adhesion region;
The ink adhering area forming system causes the ink to be ejected from the first ejection port of the second specific ink ejection head toward one of the one or a plurality of recording media. A second ink adhesion region forming step for forming the adhesion region;
A density detection step of detecting the density of the first and second liquid ink adhesion areas and the first and second ink adhesion areas;
A first density ratio value calculating step of calculating a first density ratio value that is a ratio of the density values of the first liquid ink adhesion area and the first ink adhesion area detected in the density detection process;
A second density ratio value calculating step of calculating a second density ratio value, which is a ratio between the density values of the second liquid ink adhesion area and the second ink adhesion area detected in the density detection process;
Evaluation value calculation for calculating an evaluation value that is a ratio of the first concentration ratio value calculated in the first concentration ratio value calculation step and the second concentration ratio value calculated in the second concentration ratio value calculation step Process,
And a determination step for determining whether or not the evaluation value calculated in the evaluation value calculation step is within a predetermined range centered on a predetermined reference value. .

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