Liquid ejection device and liquid ejection method

Abstract

To provide a liquid discharge device that can suppress degradation in image quality.SOLUTION: A liquid discharge device includes: a first head for imparting a first liquid to a recording medium; a second head for discharging a second liquid; a third head for discharging third liquid having the same color as that of the first liquid; a detection part for outputting a detection signal detecting an imparting state of the first liquid to the recording medium; a first movement mechanism for moving the first head and the detection part relatively to the recording medium: a second movement mechanism for moving the second head and the third head relatively to the recording medium; and a control unit for controlling discharge by the third head on the basis of the detection signal by the detection part.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a liquid ejection device and a liquid ejection method.

Background Art

[0002] Conventionally, in a liquid ejection device, after applying a white liquid as a base liquid (first liquid) to a recording medium other than white, a liquid of a color other than white (second liquid) is ejected onto the first liquid applied to the recording medium to form an image.

[0003] Also, in order to perform a cleaning process on a defective ejection nozzle in which ejection failure has occurred among a plurality of nozzles provided in a head that ejects liquid, a configuration for detecting the defective ejection nozzle from a captured image by a two-dimensional image sensor is disclosed (see, for example, Patent Document 1).

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a liquid ejection device that applies a first liquid to a recording medium, if there is an area where the first liquid is not applied, the quality of an image formed by the second liquid may deteriorate. In the configuration of Patent Document 1, since the application state of the first liquid on the recording medium is not detected, the above-described deterioration in image quality cannot be suppressed.

[0005] An object of the present invention is to provide a liquid ejection device capable of suppressing a decrease in image quality.

Means for Solving the Problems

[0006] A liquid ejection device according to one aspect of the present invention includes a first head that applies a first liquid to a recording medium, a second head that ejects a second liquid, a third head that ejects a third liquid having the same color as the first liquid, a detection unit that outputs a detection signal for detecting the application state of the first liquid on the recording medium, a first moving mechanism that relatively moves the first head and the detection unit with respect to the recording medium, a second moving mechanism that relatively moves the second head and the third head with respect to the recording medium, and a control unit that controls the ejection by the third head based on the detection signal from the detection unit.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide a liquid ejection device capable of suppressing a decrease in image quality.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Modes for Carrying Out the Invention

[0009] Hereinafter, embodiments for carrying out the invention will be described in detail with reference to the drawings. In each drawing, the same reference numerals are assigned to the same components, and redundant descriptions will be omitted as appropriate.

[0010] In the figures shown below, the directions may be indicated by the X-axis, Y-axis, and Z-axis. The X-direction along the X-axis indicates the main scanning direction, which is the moving direction of the carriage included in the liquid ejection device according to the embodiment. The Y-direction along the Y-axis indicates the sub-scanning direction, which is the moving direction of the recording medium. The Z-direction along the Z-axis indicates the direction orthogonal to both the main scanning direction and the sub-scanning direction.

[0011] Also, the direction in which the arrow points in the X-direction is denoted as the +X direction, and the opposite direction of the +X direction is denoted as the -X direction. The direction in which the arrow points in the Y-direction is denoted as the +Y direction, and the opposite direction of the +Y direction is denoted as the -Y direction. The direction in which the arrow points in the Z-direction is denoted as the +Z direction, and the opposite direction of the +Z direction is denoted as the -Z direction. However, these do not limit the orientation during the use of the liquid ejection device, and the orientation of the liquid ejection device is arbitrary.

[0012] [First Embodiment] [Configuration Example of Liquid Ejection Device 100] The liquid ejection device 100 according to the embodiment is an image forming device of a liquid ejection type that forms an image on a fabric (recording medium) such as a T-shirt by ejecting ink (liquid). The liquid ejection device 100 is a so-called serial type inkjet printer in which the head for ejecting ink moves.

[0013] FIG. 1 is a diagram for explaining the configuration of the liquid ejection device 100. As shown in FIG. 1, the liquid ejection device 100 includes a first carriage 1, a second carriage 2, a first head 3, a second head 4, a third head 5, an image sensor 6, and a control unit 7.

[0014] The liquid ejection device 100 detects the application state of the white ink in the base area Ga formed by applying the white ink to the black fabric G by the first head 3, using the image sensor 6. When the liquid ejection device 100 detects a missing area (hereinafter referred to as "missing area") where the white ink is not applied to the base area Ga due to ejection failure of the nozzles included in the first head 3 or the like, the third head 5 ejects the white ink to repair the missing area. This missing area corresponds to an example of the application state. The liquid ejection device 100 can form a high-quality image on the fabric G by ejecting ink from each head while moving the first carriage 1 and the second carriage 2 in the main scanning direction and the fabric G in the sub-scanning direction. Hereinafter, each component included in the liquid ejection device 100 will be described.

[0015] The first carriage 1 is an example of a first moving mechanism that relatively moves the first head 3 and the image sensor 6 with respect to the fabric G. The first carriage 1 fixes the first head 3 and the image sensor 6 on the first carriage 1 and moves along the moving direction 10 indicated by the solid white arrow, thereby integrally reciprocating the first head 3 and the image sensor 6 in the main scanning direction.

[0016] The second carriage 2 is an example of a second moving mechanism that relatively moves the second head 4 and the third head 5 with respect to the fabric G. The second carriage 2 fixes the second head 4 and the third head 5 on the second carriage 2 and moves along the moving direction 20 indicated by the solid white arrow, thereby integrally reciprocating the second head 4 and the third head 5 in the main scanning direction.

[0017] The liquid ejection device 100 forms a two-dimensional image on the fabric G by ejecting ink from each head while moving the first carriage 1 and the second carriage 2 in the main scanning direction and the fabric G in the sub-scanning direction, respectively. The moving direction 30 indicated by the dashed white arrow corresponds to the direction in which the fabric G is moved.

[0018] The first head 3 includes a plurality of nozzles, and by discharging white ink from the nozzles, white ink is applied to the black fabric G. The white ink applied to the fabric G by the first head 3 forms a base area Ga for forming an image on the fabric G.

[0019] For example, if there are color unevenness or the like on the fabric G, when directly discharging ink onto the fabric G to form an image, the desired color and contrast may not be obtained in the formed image, and the image quality may deteriorate. The liquid ejection device 100 forms an image on the base area Ga formed prior to image formation, thereby absorbing color unevenness or the like on the fabric G by the base area Ga and suppressing deterioration in the quality of the image formed on the fabric G.

[0020] The first head 3 includes four heads, namely heads 3W1, 3W2, 3W3, and 3W4, and white ink is discharged from each head. The number of heads included in the first head 3 is not limited to four, and may be any number. Note that the first head 3 is a general notation for heads 3W1, 3W2, 3W3, and 3W4.

[0021] The white ink applied by the first head 3 is an example of the first liquid. The fabric G is not limited to black and may be other colors. The color of the first liquid is not limited to white either and can be appropriately changed according to the color of the fabric. From the viewpoint of visibility and the like, it is preferable that the color of the first liquid is different from the color of the fabric G.

[0022] In the present embodiment, a configuration in which the first head 3 discharges ink from a plurality of nozzles is illustrated, but it is not limited thereto. For example, the first head 3 may discharge ink from a single nozzle, or may apply ink to the fabric G by a method other than liquid ejection such as coating. However, from the viewpoint of sharing the components of the first carriage 1 and the second carriage 2, it is preferable to use a liquid ejection type head as a component for applying the base ink.

[0023] The second head 4 includes four heads, namely heads 4C, 4M, 4Y, and 4K, and each head ejects inks of respective colors of cyan, magenta, yellow, and black. The inks of respective colors ejected by the second head 4 land on the base area Ga provided on the fabric G to form a color image. Incidentally, hereinafter, the inks of respective colors of cyan, magenta, yellow, and black may be collectively referred to as color inks.

[0024] The number of heads included in the second head 4 is not limited to four, and may be any number. The second head 4 is a generic notation for heads 4C, 4M, 4Y, and 4K. The inks of respective colors of cyan, magenta, yellow, and black are each an example of the second liquid, but the color of the second liquid is not limited to these, and may be other colors such as gold or green, or may be a color number of three or less. Also, a configuration may be adopted in which a plurality of heads eject ink of one color.

[0025] The third head 5 ejects white ink. The liquid ejection device 100 forms the base area Ga with the white ink ejected from the first head 3. However, if there is a defective ejection nozzle among the nozzles included in the first head 3, the white ink may not be applied to the fabric G, and a missing area may occur in the base area Ga. This defective ejection includes non-ejection where ink is not ejected, ejection bending where ink is not ejected in a desired direction, and the like.

[0026] The liquid ejection device 100 can repair the missing area in the base area Ga by ejecting and applying white ink of the same color from the third head 5 to the missing area in the base area Ga.

[0027] In the present embodiment, the third head 5 consists of one head, but is not limited thereto, and may be any number. Also, the white ink ejected by the third head 5 is an example of the third liquid, but the color of the third liquid is not limited to white, and may be other colors as long as it is the same color as the first liquid.

[0028] The image sensor 6 is an example of a detection unit that outputs a detection signal for detecting the application state of the white ink on the fabric G.

[0029] The control unit 7 controls the operation of the entire liquid ejection device 100. In particular, in the present embodiment, the control unit 7 controls the ejection by the third head 5 based on the detection signal output by the image sensor 6.

[0030] <Overall Configuration of Liquid Ejection Device 100> FIGS. 2 to 4 are diagrams illustrating the overall configuration of the liquid ejection device 100. FIG. 1 is a perspective view, FIG. 2 is a top view, and FIG. 3 is a front view. FIG. 5 is a top view showing an enlargement of the periphery of the first carriage 1 and the second carriage 2.

[0031] The liquid ejection device 100 moves the first carriage 1 in the X direction along the main guide rod 13 and the sub-guide rod 14 by driving the main scanning timing belt 12 by the main scanning motor 11. When the first carriage 1 moves, the liquid ejection device 100 periodically reads an encoder sheet 15 on which slits are formed or printed by the encoder 15a on the first carriage 1 in order to detect the position of the first carriage 1. The liquid ejection device 100 forms a base area Ga on the fabric G by ejecting ink from the first head 3 while adjusting the timing according to the reading result.

[0032] The liquid ejection device 100 moves the second carriage 2 in the X direction along the main guide rod 23 and the sub-guide rod 24 by driving the main scanning timing belt 22 by the main scanning motor 21. When the second carriage 2 moves, the liquid ejection device 100 periodically reads an encoder sheet 25 on which slits are formed or printed by the encoder 25a on the second carriage 2 in order to detect the position of the second carriage 2. The liquid ejection device 100 forms an image on the base area Ga by ejecting ink from the second head 4 while adjusting the timing according to the reading result.

[0033] Each head mounted on the first carriage and the second carriage 2 has nozzle arrays arranged in two columns in the sub-scanning direction. The liquid ejection device 100 includes head tanks for temporarily storing the ink used for ejection directly above the heads in the first carriage 1 and the second carriage 2. The head tanks are connected to the ink cartridges 8 through ink supply tubes via ink supply pumps, and receive ink replenishment from the ink cartridges 8 as necessary.

[0034] The fabric G is placed on the platen 31. The platen 31 is mounted on the platen elevating mechanism 32 and its position can be adjusted along the Z direction. The platen elevating mechanism 32 is mounted on the sub-scanning slider 33.

[0035] The sub-scanning slider 33 is controlled by a sub-scanning timing belt 35, a sub-scanning drive mechanism, and a control unit 7 along a sub-scanning guide rail 34 and is movable in the sub-scanning direction. The sub-scanning slider 33 is an example of a sub-scanning movement mechanism that relatively moves the fabric G with respect to the first carriage 1 and the second carriage 2 along the Y direction orthogonal to the X direction, which is the moving direction of the first carriage 1 and the second carriage 2.

[0036] The control unit 7 is a controller board provided in the liquid ejection device 100.

[0037] Image formation on the fabric G is performed in the following procedure. First, the user of the liquid ejection device 100 places the fabric G on the platen 31. Then, in response to an operation by the user on the operation unit 36, the liquid ejection device 100 performs an operation of completely retracting the platen 31 to the -Y direction side. During this retraction, the liquid ejection device 100 detects by the height detection sensor 37 whether the fabric G on the platen 31 collides with the first head 3, the second head 4, etc. If the fabric G collides with the first head 3, the second head 4, etc., the liquid ejection device 100 stops the retraction of the platen 31 on the spot. Or the liquid ejection device 100 returns the platen 31 to the initial position of the fabric G on the +Y direction side. When the retraction of the platen 31 to the -Y direction side is completed without problems, the liquid ejection device 100 enters a state of waiting to receive the image data that is the source of the image to be formed on the fabric G.

[0038] In the standby state described above, when the liquid ejection device 100 receives print data from a PC (Personal Computer) or the like, it starts the image formation operation. Also, when image data is previously stored in the control unit 7, the liquid ejection device 100 starts the image formation operation by the user selecting the stored image data via the operation unit 36.

[0039] When the image formation is started, the liquid ejection device 100 first moves the platen 31 to the image formation start position. Then, the liquid ejection device 100 forms an image by ejecting white ink and color ink while moving the first carriage 1 and the second carriage 2 in the +X direction or the -X direction once. In accordance with the timing when this one-time movement is completed, the liquid ejection device 100 moves the platen 31 by an appropriate amount of movement to the +Y direction side for the next image formation (line feed process).

[0040] After waiting for the movement of the platen 31 to be completed, the first carriage 1 and the second carriage 2 move once in the +X direction or the -X direction while discharging white ink and color ink to perform image formation. By repeating the movement of the first carriage 1 and the second carriage 2 in the X direction and then the movement of the platen 31 in the Y direction, a two-dimensional image can be formed in a desired area of the fabric G. When the image formation is completed, the liquid ejection device 100 returns the platen 31 to the initial position on the +Y direction side, and the image formation is completed.

[0041] The liquid ejection device 100 is provided with a first air ejection receiver 16 on the -X direction side of the first carriage 1 for discharging (air ejection) the ink that has dried and increased in viscosity by coming into contact with air during image formation. The liquid ejection device 100 is also provided with a second air ejection receiver 26 on the -X direction side of the second carriage 2 for discharging the ink that has dried and increased in viscosity by coming into contact with air during image formation.

[0042] The liquid ejection device 100 discharges the ink with increased viscosity to the first air ejection receiver 16 and the second air ejection receiver 26 according to an instruction from the control unit 7 at a predetermined timing.

[0043] The liquid ejection device 100 is provided with a first maintenance mechanism 17, which is a maintenance and recovery mechanism for the function of the first head 3, on the +X direction side of the first carriage 1. The liquid ejection device 100 is also provided with a second maintenance mechanism 27, which is a maintenance and recovery mechanism for the functions of the second head 4 and the third head 5, on the +X direction side of the second carriage 2.

[0044] The first maintenance mechanism 17 is provided with a moisture retention cap 18a and a suction cap 18b to protect the head from drying when the liquid ejection device 100 is not in operation (non-image formation).

[0045] The moisture retention cap 18a covers the nozzle surface provided with nozzles on the head and protects the nozzle surface from drying. The suction cap 18b has, in addition to the function of the moisture retention cap, a function of restoring the head to an appropriate state by sucking mainly the thickened ink from the head by a suction pump connected to the suction cap 18b. The liquid ejection device 100 discharges the ink sucked by the suction pump to a waste liquid bottle via a waste liquid tube.

[0046] Further, the first maintenance mechanism 17 includes a wiper 19 for cleaning the excess ink remaining on the nozzle surface after suction and restoring the nozzle state. The liquid ejection device 100 scrapes off the excess ink by wiping the nozzle surface with the wiper 19 after head suction, and normally forms a meniscus, which is the interface between the ink and the atmosphere, at the nozzles included in the first head 3.

[0047] Similarly, the second maintenance mechanism 27 includes a moisture retention cap, a suction cap, and a wiper, and uses these to normally form a meniscus at the nozzles included in each of the second head 4 and the third head 5.

[0048] As shown in FIG. 5, the first carriage 1 and the second carriage 2 are provided side by side along the Y direction. The first carriage 1 moves along the X direction to relatively move the first head 3 and the image sensor 6 in the main scanning direction. The second carriage 2 moves along the X direction to relatively move the second head 4 and the third head 5 in the main scanning direction.

[0049] <Configuration example of image sensor 6> FIGS. 6 and 7 are diagrams showing an example of the configuration of the image sensor 6. FIG. 6 is a front view, and FIG. 7 is a block diagram including the functional configuration of an image processing unit 65 in the image sensor 6.

[0050] As shown in FIGS. 6 and 7, the image sensor 6 includes an image pickup element 61, a light source 62, an electric element mounting substrate 63, a housing 64, an image processing unit 65, a data storage memory 66, and an interface unit 67.

[0051] While moving the image sensor 6 in the X direction by the first carriage 1, the liquid ejection device 100 irradiates the fabric G with light from the light source 62 through the opening 64a provided in the housing 64, and the imaging element 61 captures a line image along the Y direction. After the image processing unit 65 executes predetermined processing on the captured line image, the image sensor 6 outputs the processed line image as a detection signal to the control unit 7 via the upper CPU 70.

[0052] The liquid ejection device 100 can acquire a two-dimensional image of the fabric G by combining the captured line images. The liquid ejection device 100 forms the base region Ga by the first head 3, and particularly acquires a two-dimensional image of the base region Ga that is being formed on the fabric G.

[0053] The imaging element 61 is a one-dimensional imaging element in which a plurality of pixels that output voltage signals according to the intensity of the received light are arranged in a line along the Y direction. For the one-dimensional imaging element, a CCD (Charge Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor), a photodiode array, etc. can be applied. However, the imaging element is not limited to a one-dimensional imaging element and may be a two-dimensional imaging element.

[0054] The light source 62 irradiates the fabric G in order to ensure the light intensity of the light received by the imaging element 61. If the necessary received light intensity can be obtained even without the irradiation light from the light source 62, the image sensor 6 may not include the light source 62. It is preferable to apply a small light source such as an LED (Light Emitting Diode) or an LD (Laser Diode) to the light source 62.

[0055] The electric element mounting substrate 63 is a substrate on which electric elements such as the imaging element 61, the light source 62, the image processing unit 65, the data storage memory 66, and the interface unit 67 are mounted, and each is wired so as to be operable.

[0056] The housing 64 is a box-shaped member that houses the imaging element 61, the light source 62, the electric element mounting substrate 63, etc. The housing 64 is provided with an opening 64a on the bottom surface facing the fabric G. The light source 62 provided inside the housing 64 irradiates light on the fabric G through the opening 64a. The housing 64 is arranged with a gap d between it and the fabric G and is movable on the fabric G while maintaining the gap d.

[0057] The gap d is preferably as small as possible, but considering the flatness of the fabric G, it is determined so that the housing does not contact the fabric G. The gap d is, for example, about 1 [mm] to 2 [mm]. However, in the case of a fabric G that is likely to have lifting, the gap d can be increased so that the image sensor 6 and the fabric G do not come into contact.

[0058] The image processing unit 65 includes an AD (Analog / Digital) conversion unit 651, a shading correction unit 652, a gamma correction unit 653, and an image format conversion unit 654. The AD conversion unit 651 converts the analog voltage signal output by the imaging element 61 into a digital voltage signal. The shading correction unit 652 performs image processing to correct unevenness in the amount of light in the captured image. The gamma correction unit 653 performs image processing to correct the gamma characteristics (linearity characteristics) of the imaging element 61. The image format conversion unit 654 converts the captured image into a format that can be processed by the upper-level CPU (Central Processing Unit) 70.

[0059] The image processing unit 65 can realize each of the above functions with an electric circuit, and can also realize some of the functions by software (CPU). These functions may also be realized by a plurality of circuits or a plurality of software.

[0060] The data storage memory 66 is a memory that temporarily stores the data of the captured image in order to execute the processing by the image processing unit 65. The interface unit 67 is an interface that enables communication between the image processing unit 65 and the upper-level CPU 70.

[0061] <Functional Configuration Example of Control Unit 7> FIG. 8 is a block diagram showing an example of the functional configuration of control unit 7. Control unit 7 includes an imaging data calculation unit 71, an image data buffer unit 72, an image data control unit 73, a discharge nozzle table selection unit 74, a resolution information control unit 75, a discharge nozzle table storage unit 76, and an image data output unit 77. Control unit 7 can implement these functions with an electric circuit, and can also implement some of the functions with software (CPU). These functions may also be implemented by a plurality of circuits or a plurality of software.

[0062] The imaging data calculation unit 71 receives the line image data captured by the image sensor 6, and detects the missing area in the base area Ga by performing image processing on the two-dimensional image obtained by combining the line image data. The imaging data calculation unit 71 determines one or more nozzles from which white ink is to be discharged from the third head 5 in order to repair the detected missing area according to the location and size of the detected missing area, and outputs the determined nozzle information to the image data control unit 73.

[0063] The image data buffer unit 72 stores the image data transmitted after being rendered by the PC 9. When an image formation instruction is issued by the PC 9, the image formation instruction is transmitted to the image data control unit 73 via the image data buffer unit 72.

[0064] The discharge nozzle table storage unit 76 stores a table indicating the nozzles to be discharged for each movement in the X direction by the first carriage 1 and the second carriage 2. This table is read by the discharge nozzle table selection unit 74 according to the number of movements in the X direction of the first carriage 1 and the second carriage 2 read by the resolution information control unit 75, and is transmitted to the image data control unit 73.

[0065] The image data control unit 73 generates the image data to be transmitted to each of the first head 3, the second head 4, and the third head 5 based on the information received from the image data buffer unit 72 and the discharge nozzle table selection unit 74.

[0066] When the control unit 7 detects a missing area, it transmits, via the ejection nozzle table storage unit 76, information specifying the nozzles to eject for repairing the missing area among the third heads 5 from the image data output unit 77 to the third heads 5. The third heads 5 are provided assuming that ideally no ejection is to be performed. However, when a missing area is detected in the base area Ga, white ink is ejected from the specified nozzles to repair the missing area.

[0067] When no missing area is detected in the base area Ga, the control unit 7 transmits a drive waveform for slightly driving the ink in each nozzle of the third heads 5. The slight drive is a drive for vibrating the ink in the nozzle so that the ink in the nozzles where ejection is not performed does not dry. In this case, the third heads 5 do not eject ink from the nozzles and suppress ink drying by moving the ink in the nozzles by vibration.

[0068] After the repair of the missing area in the base area Ga is completed, the liquid ejection device 100 ejects color ink by the second head 4 to form a color image on the base area Ga.

[0069] <Operation Example of Liquid Ejection Device 100> FIG. 9 is a flowchart showing an example of the operation of the liquid ejection device 100. In response to an operation input reception for starting image formation by the user via the operation unit 36 or an instruction input for starting image formation from the PC 9, etc., the liquid ejection device 100 starts the operation of forming a color image on the fabric G shown in FIG. 9.

[0070] First, in step S91, the liquid ejection device 100 ejects white ink onto the fabric G by the first head 3 to form the base area Ga.

[0071] Subsequently, in step S92, the liquid ejection device 100 images the base area Ga formed on the fabric G with the image sensor 6 in order to detect the missing area in the base area Ga, and outputs the captured line image to the control unit 7 as a detection signal.

[0072] Subsequently, in step S93, the liquid ejection device 100 determines whether there is a missing area in the base area Ga based on the line image input from the image sensor 6.

[0073] In step S93, if it is determined that there is a missing area (step S93, Yes), in step S94, the liquid ejection device 100 ejects white ink with the third head 5 in order to repair the missing area. Thereafter, the liquid ejection device 100 shifts the operation to step S95. On the other hand, in step S93, if it is determined that there is no missing area (step S93, No), the liquid ejection device 100 shifts the operation to step S95.

[0074] Subsequently, in step S95, the liquid ejection device 100 determines whether to finish forming the base area Ga. This determination can be made based on, for example, whether white ink has been ejected for the entire predetermined area on the fabric G according to the image data.

[0075] In step S95, if it is determined that the formation of the base area Ga is not finished (step S95, No), the liquid ejection device 100 performs the operations after step S91 again. On the other hand, if it is determined that the formation of the base area Ga is finished (step S95, Yes), in step S96, the liquid ejection device 100 ejects color ink in order to form a color image on the base area Ga.

[0076] Subsequently, in step S97, the liquid ejection device 100 determines whether to finish image formation. This determination can be made based on, for example, whether color ink has been ejected for the entire predetermined area on the fabric G according to the image data.

[0077] In step S97, when it is determined that image formation is not completed (step S97, No), the liquid ejection device 100 repeats the operations after step S96. On the other hand, when it is determined that image formation is completed (step S97, Yes), the liquid ejection device 100 terminates the formation of the color image on the fabric G.

[0078] In this way, the liquid ejection device 100 can form a color image on the fabric G.

[0079] In the example of FIG. 9, the operation of sequentially detecting the missing regions while forming the base region Ga and sequentially repairing the missing regions when there are missing regions is illustrated, but the present invention is not limited thereto. The liquid ejection device 100 may sequentially detect the missing regions while forming the base region Ga and repair the missing regions after the formation of the entire base region Ga is completed. Alternatively, the liquid ejection device 100 may detect the missing regions after the formation of the entire base region Ga is completed and repair the missing regions after the detection of the missing regions for the entire base region Ga is completed.

[0080] Also, in the example of FIG. 9, the operation of forming a color image on the base region Ga after the formation of the base region Ga is completed is illustrated, but the liquid ejection device 100 may sequentially form a color image on the formed base region Ga while forming the base region Ga.

[0081] <Function and Effect of the Liquid Ejection Device 100> As described above, the liquid ejection device 100 includes a first head 3 that applies white ink (first liquid) to a fabric G (recording medium), a second head 4 that ejects color ink (second liquid), and a third head 5 that ejects white ink (third liquid having the same color as the first liquid). The liquid ejection device 100 also includes an image sensor 6 (detection unit) that outputs a detection signal for detecting the application state of the white ink on the fabric G, and a first carriage 1 (first movement mechanism) that relatively moves the first head 3 and the image sensor 6 with respect to the fabric G. Further, the liquid ejection device 100 includes a second carriage 2 (second movement mechanism) that relatively moves the second head 4 and the third head 5 with respect to the fabric G, and a control unit 7 that controls the ejection by the third head 5 based on the detection signal from the image sensor 6.

[0082] When a missing area is detected in the base area Ga formed by applying white ink to the fabric G by the first head 3, the third head 5 ejects white ink to repair this missing area. By this repair, since a color image can be formed on the base area Ga without a missing area, the liquid ejection device 100 can form a high-quality image on the fabric G. And a liquid ejection device capable of suppressing a decrease in image quality can be provided.

[0083] Also, in the present embodiment, the first liquid is a white liquid, the second liquid is a liquid of a color other than white, and the third liquid is a white liquid. When white ink is used to form the base area Ga, color unevenness of the fabric G can be preferably absorbed, and a high-quality image can be formed. On the other hand, if there is a missing area in the base area Ga, the missing area tends to be conspicuous. By repairing the missing area in the base area Ga formed by white ink, a high-quality image can be formed on the white base area Ga without a missing area.

[0084] In this embodiment, the first carriage 1 and the second carriage 2 move the first head 3, the image sensor 6, the second head 4, and the third head 5 along the X direction. The liquid ejection device 100 has a sub-scanning slider 33 (sub-scanning movement mechanism) that relatively moves the fabric G with respect to the first carriage 1 and the second carriage 2 along the Y direction orthogonal to the X direction. The second carriage 2 is provided on the downstream side of the first carriage 1 in the Y direction. With this configuration, while the base area Ga is formed by the first head 3, a color image can be sequentially formed on the formed base area Ga on the downstream side of the first head 3 in the Y direction. Since it is not necessary to wait for the start of forming the color image until the formation of the entire base area Ga is completed, the liquid ejection device 100 can form an image on the fabric G in a shorter time.

[0085] The third head 5 is preferably provided on the downstream side of the second head 4 in the moving direction of the second carriage 2 during image formation. For example, when the second carriage 2 moves in the -X direction and ejects color ink to form an image, the third head 5 is preferably provided on the downstream side of the second head 4 in the -X direction. With this configuration, since the base area Ga can be repaired before the ejection by the second head 4 during image formation, a color image can be sequentially formed while repairing the base area Ga.

[0086] [Second Embodiment] The liquid ejection device 100a according to the second embodiment will be described. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and redundant descriptions will be omitted as appropriate.

[0087] FIG. 10 is a diagram for explaining an example of the configuration of the liquid ejection device 100a. The liquid ejection device 100a has two third heads, a third head 5a and a third head 5b. The first carriage 1 moves the first head 3 along the X direction, and the second carriage 2 moves the second head 4 and the third head 5 along the X direction. The third head 5a and the third head 5b are arranged on both the upstream side and the downstream side of the second head 4 in the X direction.

[0088] The liquid ejection device 100a performs so-called bidirectional printing in which a color image is formed both when the second head 4 is moving in the +X direction and when it is moving in the -X direction.

[0089] When the second head 4 forms a color image while moving in the +X direction, the third head 5b ejects white ink to repair the missing area in the base area Ga. On the other hand, when the second head 4 forms a color image while moving in the -X direction, the third head 5a ejects white ink to repair the missing area in the base area Ga.

[0090] With this configuration, when the liquid ejection device 100a performs bidirectional printing, it can sequentially form a color image while repairing the missing area on the downstream side of the second head 4 in the direction in which the second carriage 2 moves during image formation. Since it is not necessary to wait for the start of color image formation until the detection of the missing area in the entire base area Ga is completed, an image can be formed on the fabric G in a shorter time. Note that other effects are the same as those of the first embodiment.

[0091] As described above, examples of embodiments of the present invention have been described. However, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

[0092] In the above-described embodiments, the first carriage 1 and the second carriage 2 each move to relatively move the first head 3 and the image sensor 6 with respect to the fabric G, and also relatively move the second head 4 and the third head 5 with respect to the fabric G. However, the configuration is not limited to this. The first carriage 1 or the second carriage 2 may not move, and the fabric G may move to relatively move the first head 3 and the image sensor 6 with respect to the fabric G, and also relatively move the second head 4 and the third head 5 with respect to the fabric G. Further, the first carriage 1 and the second carriage 2 may be made of a common member and moved integrally. That is, the first moving mechanism and the second moving mechanism may be made of a common mechanism.

[0093] In the above-described embodiments, an inkjet printer has been mainly described as an example of the liquid ejection device, but the present invention is not limited to this. This liquid ejection device can also include means related to feeding, transporting, and paper discharging of an object to which liquid can adhere, as well as a pretreatment device, a post-treatment device, and the like.

[0094] Examples of the liquid ejection device include an image forming device that ejects ink to form an image on a sheet of paper, and a three-dimensional modeling device (three-dimensional forming device) that ejects a modeling liquid onto a powder layer formed in a layer of powder in order to form a three-dimensional object (three-dimensional formed object).

[0095] Further, the liquid ejection device is not limited to those in which a significant image such as characters or figures is visualized by the ejected liquid. For example, those that form a pattern or the like having no meaning by itself, and those that create a three-dimensional image are also included.

[0096] The above "object to which liquid can adhere" means an object to which liquid can adhere at least temporarily, such as an object to which liquid adheres and adheres firmly, or an object to which liquid adheres and penetrates. Specific examples include recording media such as paper, recording paper, recording sheets, films, and fabrics, electronic components such as electronic substrates and piezoelectric elements, powder layers (powder layers), organ models, and media such as inspection cells, and include all objects to which liquid adheres unless otherwise particularly limited.

[0097] The material of the above-mentioned "thing to which liquid can adhere" may be paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc., as long as liquid can adhere temporarily.

[0098] Also, the "liquid" may be any liquid having a viscosity and surface tension that can be discharged from the head, and is not particularly limited. However, it is preferably a liquid that has a viscosity of 30 mPa·s or less at normal temperature and pressure, or by heating or cooling. More specifically, it includes solvents such as water and organic solvents, colorants such as dyes and pigments, polymerizable compounds, resins, functional material-imparting materials such as surfactants, biocompatible materials such as DNA, amino acids, proteins, and calcium, edible materials such as natural pigments, etc., and solutions, suspensions, emulsions, etc. containing these can be used, for example, in applications such as inkjet inks, surface treatment liquids, components for electronic elements and light-emitting elements, liquids for forming electronic circuit resist patterns, and material liquids for three-dimensional modeling.

[0099] As an energy source for discharging liquid, those using piezoelectric actuators (laminated piezoelectric elements and thin-film piezoelectric elements), thermal actuators using electrothermal conversion elements such as heating resistors, electrostatic actuators composed of diaphragms and counter electrodes, etc. are included.

[0100] Also, there is a device in which the liquid discharge head and the thing to which liquid can adhere move relatively, but it is not limited to this. Specific examples include serial type devices that move the liquid discharge head.

[0101] Also, as other liquid discharge devices, there are treatment liquid coating devices that discharge a treatment liquid onto paper in order to coat the surface of the paper for the purpose of modifying the surface of the paper, injection granulation devices that inject a composition liquid in which raw materials are dispersed in a solution through nozzles to granulate fine particles of the raw materials, etc.

[0102] Also, in the terms of the embodiments, image formation, recording, printing, imprinting, printing, modeling, etc. are all synonymous.

[0103] An embodiment includes a liquid ejection method. For example, the liquid ejection method is a liquid ejection method by a liquid ejection device, wherein the liquid ejection device applies a first liquid to a recording medium by a first head, ejects a second liquid by a second head, ejects a third liquid of the same color as the first liquid by a third head, outputs a detection signal detected by a detection unit for the application state of the first liquid on the recording medium, relatively moves the first head and the detection unit with respect to the recording medium by a first movement mechanism, relatively moves the second head and the third head with respect to the recording medium by a second movement mechanism, and controls the ejection by the third head based on the detection signal by the detection unit by a control unit. By such a liquid ejection method, the same effects as those of the above-described liquid ejection device 100 can be obtained.

[0104] The numbers such as ordinal numbers and quantities used in the description of the embodiment are all exemplified for specifically explaining the technology of the present invention, and the present invention is not limited to the exemplified numbers. Also, the connection relationship between components is exemplified for specifically explaining the technology of the present invention, and the connection relationship for realizing the functions of the present invention is not limited thereto.

[0105] Each function of the embodiment can be realized by one or a plurality of processing circuits. Here, the "processing circuit" in this specification means a processor programmed to execute each function by software like a processor implemented by an electronic circuit, an ASIC (Application Specific Integrated Circuit), a DSP (digital signal processor), an FPGA (field programmable gate array) designed to execute each function described above, and devices such as conventional circuit modules.

Explanation of Reference Numerals

[0106] 1 First carriage (an example of the first movement mechanism) 2 Second carriage (an example of the second movement mechanism) 3 First head 4 Second head 5, 5a, 5b Third head 6 Image sensor (an example of a detection unit) 61 Image pickup element 62 Light source 63 Electric element mounting substrate 64 Housing 65 Image processing unit 66 Memory for data storage 67 Interface unit 7 Control unit 8 Ink cartridge 70 Upper CPU 71 Image pickup data calculation unit 72 Image data buffer unit 73 Image data control unit 74 Discharge nozzle table selection unit 75 Resolution information control unit 76 Discharge nozzle table storage unit 77 Image data output unit 9 PC 10, 20, 30 Moving direction (an example of a predetermined moving direction) 31 Platen 33 Sub-scanning slider (an example of a sub-scanning movement mechanism) 100, 100a Liquid discharge device G Cloth (an example of a recording medium) Ga Underlying area

Prior art documents

Patent documents

[0107]

Patent Document 1

Claims

1. A first head for applying a first liquid to a recording medium, a second head for discharging a second liquid, a third head for discharging a third liquid of the same color as the first liquid, a detection unit that outputs a detection signal detecting the application state of the first liquid on the recording medium, a first moving mechanism that relatively moves the first head and the detection unit with respect to the recording medium, a second moving mechanism that relatively moves the second head and the third head with respect to the recording medium, and a control unit that controls the discharge by the third head based on the detection signal from the detection unit. A liquid discharge device having the same.

2. The first liquid is a white liquid, the second liquid is a liquid of a color other than white, The liquid discharge device according to claim 1, wherein the third liquid is a white liquid.

3. The first moving mechanism and the second moving mechanism move the first head, the detection unit, the second head, and the third head along a predetermined moving direction, A sub-scanning moving mechanism that relatively moves the recording medium along a direction orthogonal to the predetermined moving direction with respect to the first moving mechanism and the second moving mechanism, The liquid discharge device according to claim 1 or 2, wherein the second moving mechanism is provided on the downstream side of the first moving mechanism in a direction orthogonal to the predetermined moving direction.

4. Having a plurality of the third heads, The first moving mechanism moves the first head along a predetermined moving direction, The second moving mechanism moves the second head and the third head along the predetermined moving direction, The liquid discharge device according to any one of claims 1 to 3, wherein the third head is disposed on both the upstream side and the downstream side of the second head in the predetermined moving direction.

5. A first head for applying a first liquid to a recording medium, a second head for discharging a second liquid, a third head for discharging a third liquid of the same color as the first liquid, a detection unit that outputs a detection signal detecting the application state of the first liquid on the recording medium, a first moving mechanism that relatively moves the first head and the detection unit with respect to the recording medium, A liquid discharge method by a liquid discharge device having a second moving mechanism that relatively moves the second head and the third head with respect to the recording medium, the liquid discharge method controlling the discharge by the third head based on the detection signal from the detection unit.

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