JP2022067984A - Liquid ejection device and liquid ejection method - Google Patents

Abstract

To make density unevenness and gloss unevenness in an image inconspicuous.SOLUTION: A liquid ejection device according to an embodiment of the present invention includes: a carriage that holds a liquid ejection unit that ejects a liquid from a plurality of nozzles arranged in a sub-scanning direction onto a recording medium; a first driving unit that moves the carriage and the recording medium relative to each other in the sub-scanning direction; a second driving unit that moves the carriage and the recording medium relative to each other in a main scanning direction intersecting the sub-scanning direction; and a control unit that controls the liquid ejection unit and the first and second driving units so as to record an image on the recording medium, based on predetermined mask data; wherein the control unit executes control based on the mask data changing in two or more periodic components in the sub-scanning direction in terms of a printing proportion indicating a proportion of the liquid attached per unit area of the recording medium.SELECTED DRAWING: Figure 6

Description

The present invention relates to a liquid discharge device and a liquid discharge method.

A liquid ejection device that ejects a liquid and records an image on a recording medium while relatively moving a head unit having a plurality of nozzles and a recording medium in each of a main scanning direction and a sub-scanning direction intersecting the main scanning direction is known. Has been done.

Further, in order to make the density unevenness of the image inconspicuous, regarding the printing rate indicating the ratio of liquid adhering per unit area, the printing rate by the recording head in the joint area of the recording head group is the recording other than the joint area. A configuration for recording an image based on mask data smaller than the printing rate by the head is disclosed (see, for example, Patent Document 1).

However, in the configuration of Patent Document 1, either density unevenness or gloss unevenness may occur in the image.

An object of the present invention is to make uneven density and uneven gloss in an image inconspicuous.

The liquid ejection device according to one aspect of the present invention includes a carriage that holds a liquid ejection unit that ejects liquid from a plurality of nozzles arranged in the sub-scanning direction to a recording medium, and the carriage and the recording medium in the sub-scanning direction. An image is recorded on the recording medium based on a first drive unit for relative movement, a second drive unit for relative movement of the carriage and the recording medium in a main scanning direction intersecting the sub-scanning direction, and predetermined mask data. As such, it has a control unit for controlling the liquid discharge unit and the first and second drive units, and the control unit adheres the liquid per unit area of the recording medium. The printing rate indicating the ratio is controlled based on the mask data that changes with two or more periodic components in the sub-scanning direction.

According to the present invention, uneven density and uneven gloss in an image can be made inconspicuous.

It is a perspective view which shows the whole structure example of the recording apparatus which concerns on 1st Embodiment. It is a figure which shows the structural example of the carriage which concerns on 1st Embodiment. It is a figure of the hardware configuration example of the recording apparatus which concerns on 1st Embodiment. It is a figure of the functional configuration example of the controller unit which concerns on 1st Embodiment. It is a figure which shows various image formation sequences. It is the figure of the mask data which concerns on 1st Embodiment, (a) is the figure of the arrangement example of the recording head, (b) is the figure of the comparative example, (c) is the figure of 1st Embodiment. It is a figure which shows the change example of the ink adhesion amount in the sub-scanning direction. It is a figure which shows the example of the recording method by the recording apparatus which concerns on 2nd Embodiment, (a) is the figure which shows the division example of a head unit, (b) is the figure which shows the complementation of a pixel.

Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In each drawing, the same components may be designated by the same reference numerals and duplicate explanations may be omitted. Further, the embodiments shown below exemplify a liquid discharge device for embodying the technical idea of the present invention, and the present invention is not limited to the embodiments shown below. The dimensions, materials, shapes, relative arrangements, etc. of the components described below are not intended to limit the scope of the present invention to the specific description, but are intended to be exemplified. It is a thing. In addition, the size and positional relationship of the members shown in the drawings may be exaggerated in order to clarify the explanation.

Further, in the description of the embodiment, the main scanning direction is the X-axis direction, the sub-scanning direction intersecting the main scanning direction is the Y-axis direction, and the direction orthogonal to both the X-axis direction and the Y-axis direction is the Z-axis direction. .. The direction in which the arrow points in the X-axis direction is referred to as the X-axis positive direction, the direction opposite to the X-axis positive direction is referred to as the X-axis negative direction, and the direction in which the arrow points in the Y-axis direction is referred to as the Y-axis positive direction. The direction opposite to the positive direction of the Y axis is referred to as the negative direction of the Y axis, the direction in which the arrow points in the Z axis direction is referred to as the positive direction of the Z axis, and the opposite direction of the positive direction of the Z axis is referred to as the negative direction of the Z axis. However, these do not limit the direction of the liquid discharge device, and the direction of the liquid discharge device is arbitrary.

The liquid discharge device according to the embodiment has a carriage that holds a liquid discharge unit that discharges liquid from a plurality of nozzles arranged in the sub-scanning direction to a recording medium, and a first drive that moves the carriage and the recording medium relative to each other in the sub-scanning direction. Has a part. Further, a second drive unit that moves the carriage and the recording medium relative to each other in the main scanning direction intersecting the sub-scanning direction, a liquid ejection unit, a first unit, and a liquid ejection unit so as to record an image on the recording medium based on predetermined mask data. It has a second drive unit and a control unit that controls.

This liquid discharge device is a so-called serial type liquid discharge device that discharges liquid while the head unit moves together with the carriage and records an image on a recording medium. In such a liquid ejection device, when recording an image, the overlapping state of the liquid on the recording medium differs depending on the timing of landing on the recording medium, which may cause uneven density in the image on the recording medium. ..

When the liquid discharge device uses an ultraviolet curable liquid, the carriage moves to discharge the liquid and irradiates ultraviolet light to record an image on a recording medium. At this time, the irradiation time of ultraviolet light differs depending on the distance from the liquid landing on the recording medium to the irradiation unit, and the way the liquid spreads on the recording medium differs depending on the curing speed. The above image may have uneven gloss.

On the other hand, in the embodiment, the liquid discharge unit and the first and second drive units are controlled based on the mask data in which the printing rate changes with two or more periodic components in the sub-scanning direction.

As a result, by recording an image based on mask data that changes with two or more kinds of periodic components, two or more kinds of density unevenness are overlapped and offset to make the density unevenness inconspicuous. Further, when an ultraviolet curable liquid is used, the gloss unevenness is made inconspicuous by overlapping and canceling the gloss unevenness of two or more periodic components.

Here, the printing ratio means the ratio of adhering the liquid per unit area of the recording medium. The larger the printing rate, the larger the amount of liquid adhered to the recording medium. Further, the mask data refers to data for designating effective pixels that are allowed to be recorded on a recording medium. It should be noted that this mask is processing mask data in which effective pixels and invalid pixels are arranged two-dimensionally, and is not a mask member.

Hereinafter, an embodiment of an inkjet recording device that ejects ultraviolet curable ink onto non-permeable paper and records an image will be described as an example of a liquid ejection device. The non-penetrating paper means a paper in which ink does not easily penetrate into the inside. Non-permeable paper is an example of a recording medium. However, the recording medium is not limited to this, and may be paper such as plain paper or glossy paper other than impermeable paper, film or the like. Ink is an example of a liquid.

In the following, for the sake of simplicity, the inkjet recording device is simply abbreviated as a recording device.

Further, in the terms of the embodiment, image formation, recording, printing, printing, and printing are all synonymous. Further, the liquid may have a viscosity and surface tension that can be discharged from the liquid discharge head, and is not particularly limited, but the liquid has a viscosity of 30 mPa · s or less at room temperature, under normal pressure, or by heating or cooling. It is preferable to have. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, polymerizable compounds, resins, functionalizing materials such as surfactants, biocompatible materials such as DNA, amino acids and proteins, and calcium. , Solvents, suspensions, emulsions, etc. containing edible materials such as natural pigments, such as inks for inkjets, surface treatment liquids, components of electronic and light emitting elements, and formation of electronic circuit resist patterns. It can be used in applications such as liquids and material liquids for three-dimensional modeling.

The recording head is a functional component that discharges and injects liquid from a nozzle. Piezoelectric actuators (laminated piezoelectric elements and thin-film piezoelectric elements), thermal actuators that use electric heat conversion elements such as heat-generating resistors, and electrostatic actuators that consist of a vibrating plate and counter electrodes are used as energy sources for discharging liquid. Includes what to do.

[First Embodiment]
<Overall configuration example of recording device 10>
First, with reference to FIG. 1, the overall configuration of the recording device 10 according to the first embodiment will be described.

FIG. 1 is a perspective view showing an example of the overall configuration of the recording device 10. As shown in FIG. 1, the recording device 10 includes a platen 15 on which the paper 101 is placed, left and right side plates 18a and 18b, a guide rod 19, a guide rail 29, and a carriage 200.

The carriage 200 is supported by guide rods 19 spanning the left and right side plates 18a and 18b and can move in the X-axis direction (main scanning direction). As a result, the paper 101 and the carriage 200 can be relatively moved in the main scanning direction. Further, it can be moved in the Z-axis direction (vertical direction) by an elevating mechanism (not shown).

Further, the carriage 200, the guide rod 19 and the side plates 18a and 18b can be integrally moved in the Y-axis direction (sub-scanning direction) along the guide rail 29 provided at the lower part of the platen 15. As a result, the paper 101 and the carriage 200 can be relatively moved in the sub-scanning direction.

Although FIG. 1 shows a configuration example in which the carriage 200 can move in both the main scanning direction and the sub-scanning direction, the head unit 300 and the paper 101 of the carriage 200 are relative to each other in the main scanning direction and the sub-scanning direction, respectively. If it can be moved, it is not limited to this. For example, the carriage 200 may be moved in the main scanning direction and the paper 101 may be moved in the sub-scanning direction, or the paper 101 may be moved in the main scanning direction and the sub-scanning direction.

<Example of Carriage 200 Configuration>
Next, the configuration of the carriage 200 will be described with reference to FIG. FIG. 2 illustrates an example of a carriage configuration. FIG. 2 is a view of the carriage 200 of FIG. 1 as viewed from the negative direction side of the Z axis.

The carriage 200 is a box-shaped member whose Z-axis negative direction side is open. As shown in FIG. 2, the carriage 200 has a head unit 300 and irradiation units 400a and 400b inside the box-shaped member. The carriage 200 holds the head unit 300 and the irradiation units 400a and 400b so as to face the paper arranged on the negative side of the Z axis of the carriage 200.

The head unit 300 has recording head groups 300K, 300C, 300M and 300Y arranged in the sub-scanning direction.

Of these, the recording head group 300K includes recording heads 301K, 302K and 303K. Each of the recording heads 301K, 302K, and 303K has a piezoelectric element as a pressure generating portion, contracts in response to a drive signal, and can eject black (K) ink by a pressure change accompanying the contraction.

The carriage 200 is arranged so that the recording head 302K is slightly displaced in the main scanning direction and overlaps with the recording heads 301K and 303K in the sub-scanning direction. Such an arrangement is called a staggered arrangement. That is, the carriage 200 arranges the recording heads 301K, 302K, and 303K in a staggered manner.

Each of the recording heads 301K, 302K, and 303K is an example of a liquid ejection unit that ejects liquid from a plurality of nozzles arranged in the sub-scanning direction to the recording medium. Each of the recording heads 301K, 302K and 303K can eject ink to the negative side of the Z axis through each nozzle.

The head unit 300 fixed to the carriage 200 can eject ink from the recording heads 301K, 302K, and 303K to the paper arranged on the negative side of the Z axis of the carriage 200. By arranging the recording heads in a staggered pattern, it is possible to prevent the nozzles from being missing between the recording heads 301K, 302K and 303K in the sub-scanning direction.

Since the recording head groups 300C, 300M, and 300Y also have the same configuration and functions as the recording head group 300K except that the colors are different, overlapping description will be omitted.

The carriage 200 fixes the irradiation unit 400a on the negative side of the X-axis in the carriage 200, and fixes the irradiation unit 400b on the positive side of the X-axis in the carriage 200. Each of the irradiation units 400a and 400b is an example of an irradiation unit that irradiates the ink ejected by the head unit 300 and landed on the paper with ultraviolet light. For example, UV (Ultra Violet) lamps can be used to configure the irradiation units 400a and 400b. The ultraviolet curable ink can be cured, solidified, and adhered to the paper by being irradiated with ultraviolet light after landing on the paper.

As the ultraviolet curable ink, for example, an ink containing a methacrylate-based monomer can be used. The methacrylate-based monomer has the characteristics that the skin sensitivity is relatively weak and the degree of curing shrinkage is large.

In the present embodiment, the recording head groups 300K, 300C, 300M, and 300Y in the head unit 300 exemplify a configuration in which three recording heads are arranged in the sub-scanning direction, respectively, but the number of recording heads is limited to three. It is not something that will be done. For example, the head unit 300 may arrange two or four or more recording heads in the sub-scanning direction.

Further, the head unit 300 may include a recording head group that ejects not only inks of K, C, M, and Y colors but also inks of other colors. Inks of other colors also include clear clear inks.

<Hardware configuration example of recording device 10>
Next, the hardware configuration of the recording device 10 will be described with reference to FIG. FIG. 3 is a block diagram illustrating an example of the hardware configuration of the recording device 10.

As shown in FIG. 3, the recording device 10 includes a controller unit 3, a detection group 4, a transport unit 100, a carriage 200, a head unit 300, an irradiation unit 400, and a maintenance unit 500.

Of these, the controller unit 3 has a unit control circuit 31, a memory 32, a CPU (Central Processing Unit) 33, and an I / F (Interface) 34. Here, as shown by being surrounded by a broken line in FIG. 3, the irradiation unit includes the controller unit 3 and the irradiation unit 400, and irradiates the ink on the paper 101 with ultraviolet light to cure the ink.

The I / F 34 is an interface for connecting the recording device 10 and the PC (Personal Computer) 2 which is an external device. The connection form between the recording device 10 and the PC 2 may be any, and the connection can be made by connecting via a network, directly connecting the two with a communication cable, or the like.

The CPU 33 uses the memory 32 as a work area to control each unit of the recording device 10 via the unit control circuit 31. Specifically, the CPU 33 controls each unit based on the image data received from the PC 2 and the data detected by the detection group 4, and records the image on the paper 101.

The detection group 4 is various sensors provided in the recording device 10 such as an encoder sensor that detects the position of the carriage 200 in the main scanning direction.

The printer driver is installed on PC2. The printer driver generates image data to be transmitted to the recording device 10. The image data includes command data for operating the carriage 200 of the recording device 10 and pixel data related to the image to be recorded.

The transport unit 100 is a unit provided with a transport mechanism for transporting the paper 101. The maintenance unit 500 has a maintenance / recovery mechanism for the ejection function of each recording head included in the head unit 300. The maintenance / recovery mechanism includes a cap for covering the nozzle surface to protect the nozzle of the recording head from drying during the period when the recording device 10 does not record.

This cap is a moisturizing cap that purely covers the nozzle surface and has a function only to protect it from drying, and in addition to the function of a moisturizing cap, it is connected to a suction pump and sucks thickened ink from the recording head. Includes two types of caps.

<Recording operation example>
Next, with reference to FIG. 3, the image recording operation on the recording medium by the recording device 10 will be described.

First, the carriage 200 moves in the sub-scanning direction based on the drive signal from the CPU 33, and stops at the initial position for recording an image.

Subsequently, the carriage 200 is moved to a height suitable for ink ejection by the head unit 300 by driving the elevating mechanism based on the drive signal from the CPU 33. This height is, for example, a height at which the gap between the paper and the nozzle of the recording head becomes 1 mm. It is preferable to drive and control the elevating mechanism based on the detection signal of the height sensor that detects the height of the head unit 300.

Subsequently, the carriage 200 reciprocates in the main scanning direction based on the drive signal from the CPU 33, and at the time of this reciprocating movement, the head unit 300 ejects ink based on the drive signal from the CPU 33. As a result, the recording device 10 records an image for one scan in the main scanning direction on the paper.

Subsequently, the carriage 200 moves by one scan in the sub-scanning direction based on the drive signal from the CPU 33.

Hereinafter, the recording device 10 performs relative movement in the main scanning direction for recording an image for one scan and sub-scanning for moving the carriage 200 in the sub-scanning direction for one scan until the recording of the image on the recording medium is completed. Relative movement in the direction is performed alternately.

Then, when the recording of the image on the paper is completed, it waits until the time for smoothing the ink elapses, and after that, the irradiation unit 400 irradiates ultraviolet light to cure the ink on the paper, and the ink is printed on the paper. And fix the image.

<Example of functional configuration of controller unit 3>
Next, the functional configuration of the controller unit 3 included in the recording device 10 will be described. FIG. 4 is a block diagram showing an example of the functional configuration of the controller unit 3. As shown in FIG. 4, the controller unit 3 has an image processing unit 12 and a control unit 30. Further, the image processing unit 12 has a data receiving unit 121, a data generation unit 122, and a data output unit 123.

The data receiving unit 121 receives image data from the PC 2. The image data is information such as the shape and color of the image to be recorded. The data generation unit 122 performs predetermined data processing such as CMYK conversion processing, degrading processing, and image conversion processing on the image data received by the data receiving unit 121, and records the image data on the paper 101 based on the image data. Generate recorded data. The data output unit 123 outputs the generated recorded data to the control unit 30.

Further, the control unit 30 includes a recording unit 14, a recording mode receiving unit 21, an irradiation driving unit 22, a first driving unit 23, a second driving unit 24, and a recording control unit 28.

The recording unit 14 is a head drive unit that ejects ink to the head unit 300 based on the recording data controlled by the recording control unit 28. The recording mode receiving unit 21 receives information regarding the recording mode.

The first drive unit 23 moves the carriage 200 in the sub-scanning direction, and moves the carriage 200 and the paper relative to each other in the sub-scanning direction. The second drive unit 24 moves the carriage 200 in the main scanning direction, and moves the carriage 200 and the paper relative to each other in the main scanning direction.

The recording control unit 28 controls the recording unit 14, the first drive unit 23, and the second drive unit 24 so as to record an image on paper based on predetermined mask data.

Specifically, the recording control unit 28 receives the recorded data from the image processing unit 12, and ejects ink corresponding to each pixel of the recorded data from each recording head in the head unit 300 according to the received recording data. In addition, the recording unit 14, the first drive unit 23, the second drive unit 24, and the irradiation drive unit 22 are controlled.

Further, the recording control unit 28 includes a mask setting unit 281, a mask storage unit 282, and a mask processing unit 283.

Of these, the mask setting unit 281 sets the mask data in a predetermined state and stores it in the mask storage unit 282 realized by the memory 32 or the like. The mask setting unit 281 inputs, for example, mask data generated or edited in a predetermined state via an input interface such as a mouse or keyboard of the PC2 by the administrator or the user of the recording device 10 via the I / F 34, and masks the mask. It is stored in the storage unit 282. The mask data will be described in detail with reference to FIG. 6 separately.

The mask processing unit 283 acquires mask data with reference to the mask storage unit 282, and executes the mask processing. Here, the mask processing uses mask data for designating effective pixels that are allowed to be recorded on paper, and is based on the logical product of the image data to be recorded and the mask, and only the effective pixels from the image data to be recorded. Refers to the process of generating thinned-out image data extracted from. Here, the thinned image means an image recorded on a recording medium based on mask data, and the thinned image data means an image data for recording a thinned image on a recording medium.

Among the pixels included in the recorded data, the pixel corresponding to the effective pixel is a pixel in which dots are recorded on the paper, and the invalid pixel not corresponding to the effective pixel is a pixel in which dots are not recorded on the paper. Therefore, the recording device 10 can acquire the thinned-out image data in which the predetermined pixel of the recorded data is invalidated and thinned out by the mask processing.

The recording device 10 ejects ink to the head unit 300 based on the thinned image data to record a thinned image, which is an image in which the portion corresponding to the invalid pixel in the original image is thinned. ..

The recording device 10 records thinned-out images on paper so as to complement each other with invalid pixels while performing relative movements in the main scanning direction and the sub-scanning direction a plurality of times, and synthesizes the recorded thinned-out images. By doing so, the image can be recorded on the paper.

<Various recording sequences>
Next, a sequence of recording by the recording device 10 will be described with reference to FIG. FIG. 5 is a diagram illustrating various recording sequences.

As an image conversion process, the data generation unit 122 (see FIG. 4) records an image by scanning the head unit once in the main scanning direction according to the recording width, the recording order, and the configuration of each recording head of the head unit. Each time, the image data is converted into the recorded data.

One of the plurality of squares shown in FIGS. 5A to 5H represents one dot of the recorded data. The numbers inside the squares indicate the scanning order of the head unit. The recording device 10 records an image on paper by ejecting the carriage by the head unit in the order shown in FIG. 5 while moving the carriage in the main scanning direction and the sub-scanning direction.

Here, the number of striking in the main scanning direction is referred to as a pass. Specifically, if the number of striking in the main scanning direction is once, it is referred to as one pass, and if it is twice, it is referred to as two passes.

Further, the number of striking in the sub-scanning direction is referred to as interlacing. Specifically, if the number of striking in the sub-scanning direction is once, it is referred to as 1/1 interlace, and if it is twice, it is referred to as 1/2 interlace.

Further, the number of times the image recording is completed is referred to as the number of times N (N is a natural number). Specifically, in the case of the 1-pass 1/1 interlace shown in FIG. 5 (b), N = 1. Further, in the case of the 2-pass 1/1 interlace shown in FIG. 5 (c) or the 1-pass 1/2 interlace shown in FIG. 5 (d), N = 2.

Further, in the case of the 2-pass 1/2 interlace shown in FIG. 5 (e), N = 4. In the case of the 4-pass 1/2 interlace shown in FIG. 5 (f) or the 2-pass 1/4 interlace shown in FIG. 5 (g), N = 8. In the case of the 4-pass 1/4 interlace shown in FIG. 5 (h), N = 16.

The 1-pass sequence shown in FIGS. 5 (b) and 5 (d) is shown in the 1-pass recording mode, FIG. 5 (c), FIG. 5 (e), FIG. 5 (f), FIG. 5 (g), and FIG. The sequence of the plurality of passes shown in 5 (h) is referred to as a multipath recording mode.

The recording device 10 sets the carriage 200 in the sub-scanning direction with respect to the target region PA when the length (length L1) equal to or less than the length that the head unit can discharge the liquid at one time is the length in the sub-scanning direction. The carriage 200 is scanned N times in the main scanning direction while being conveyed, and ink is ejected into the target area PA.

By default, the recording device 10 specifies a recording mode such as a 1-pass recording mode, a multi-pass recording mode, or an interlaced recording mode, and records the number of multi-passes in the multi-pass recording mode or the number of interlaces in the interlaced recording mode. Specify the conditions. The recording device 10 stores the designated recording mode and recording conditions in the memory 32 or the like.

<Example of mask data>
Next, the mask data will be described with reference to FIG. 6A and 6B are diagrams for explaining mask data, FIG. 6A is a diagram showing an arrangement example of recording heads 301K, 302K and 303K in a recording head group 300K, and FIG. 6B is a diagram showing mask data 60X according to a comparative example. , (C) is a diagram showing an example of mask data 60 according to the present embodiment. The configuration diagram of the head unit 300 of FIG. 2 will also be described with reference to the appropriate reference.

In the mask data 60X of FIG. 6B and the mask data 60 of FIG. 6C, the black portion represents the effective pixel for recording dots on the paper, and the white portion represents the invalid pixel for recording dots on the paper. There is.

As shown in FIGS. 6 (a), 6 (b) and 6 (c), the lengths of the mask data 60X and 60 in the X-axis direction (main scanning direction) are the respective main scanning of the recording head group 300K. Corresponds to the length in the direction. For example, it substantially corresponds to the sum of the length of the recording head 301K in the main scanning direction and the length of the recording head 302K in the main scanning direction.

The lengths of the mask data 60X and 60 in the Y-axis direction (sub-scanning direction) correspond to the lengths of the recording head group 300K in the respective sub-scanning directions. For example, it substantially corresponds to the sum of the length of the recording head 301K in the sub-scanning direction, the length of the recording head 302K in the sub-scanning direction, and the length of the recording head 303K in the sub-scanning direction minus the overlap. ..

Although the arrangement of the recording head group 300K is illustrated in FIG. 6A, the arrangement is the same for the recording head groups 300C, 300M and 300Y.

One mask data is applied to one color recording head group. Further, as shown in FIGS. 6B and 6C, the distribution of the number of effective pixels (invalid pixels) is different between the mask data 60X and the mask data 60.

In the mask data 60X, the number of effective pixels is small and whitish on the positive direction side of the Y axis, and the number of effective pixels increases toward the vicinity of the center in the Y axis direction and gradually becomes blackish. Further, the number of effective pixels decreases and becomes whitish from the vicinity of the center of the Y-axis toward the negative direction of the Y-axis. In the mask data 60X, the number of effective pixels changes by the length of one cycle of LX in the Y-axis direction in this way. The printing rate changes by one cycle in the Y-axis direction according to the number of effective pixels, and the gloss of the image changes by one cycle according to the amount of ink adhered to the paper according to the printing rate.

On the other hand, in the mask data 60, the first cycle component in which the length of one cycle is L1 and the number of effective pixels changes by 74 cycles in the Y-axis direction, and the length of one cycle is L2 and the effective pixels are by three cycles. A second periodic component whose number changes is superimposed and included.

Depending on the number of effective pixels, the printing rate changes by 74 cycles when the length of one cycle is L1 and the printing rate changes by three cycles when the length of one cycle is L2 in the Y-axis direction. The gloss of the image includes a periodic component that changes by 74 cycles and a periodic component that changes by 3 cycles according to the amount of ink adhered to the paper according to the printing rate. By including such two types of periodic components, it becomes difficult to visually recognize the uneven gloss of the image.

Here, in the recording device 10, when recording an image while the carriage 200 is moving, the curing speed of the ink differs depending on the distance from the ink landing on the paper to each of the irradiation units 400a and 400b.

Since the way the ink spreads on the paper differs depending on the curing speed, the thickness and shape of the ink differ depending on the region on the paper, resulting in a difference in gloss. As a result, the image on the paper may have uneven gloss in which high-gloss areas and low-gloss areas coexist. Especially in the Y-axis direction, it often occurs in a cycle corresponding to the line feed width.

The line feed width length Lc shown in FIG. 6 (c) shows an example of the line feed width length of the carriage in the Y-axis direction. The line feed width length Lc corresponds to the interval at which the carriage 200 moves in the Y-axis direction when recording an image on paper.

In the example shown in FIG. 6C, the line feed width 61 is included in the sizes of the mask data 60X and 60 in the Y-axis direction for five cycles. Therefore, in the image recorded on the paper, gloss unevenness corresponding to 5 cycles occurs in the cycle corresponding to the line feed width 61.

When the mask data 60X according to the comparative example is used, the gloss of the image changes by about one cycle, so that the gloss unevenness generated in the cycle corresponding to the line feed width 61 may be conspicuous.

On the other hand, when the mask data 60 according to the present embodiment is used, the periodic component of the gloss unevenness corresponding to the line feed width 61 overlaps with the first and second periodic components of the gloss unevenness, so that the cycle of each gloss unevenness is overlapped. More components are offset. As a result, the gloss unevenness of the image can be made inconspicuous as compared with the case where the mask data 60X is used.

In order to make the gloss unevenness due to the line feed width of the carriage inconspicuous, it is preferable to make the length of each cycle of the first and second cycle components different from the length of the line feed width of the carriage in the sub-scanning direction. .. As shown in FIG. 6 (c), the length L1 of one cycle in the first cycle component and the length L2 of one cycle in the second cycle component are different from the line feed width length Lc, respectively.

Further, in the mask data 60, it is more preferable that the number of effective pixels in the both end regions of the mask data in the Y-axis direction is smaller than the number of effective pixels in the regions other than the both end regions. In other words, it is more preferable that the printing ratio in the both end regions of the mask data in the Y-axis direction is lower than the printing ratio in the regions other than the both end regions.

FIG. 7 shows the Y-axis of the amount of ink adhered to the paper when mask data is used in which the printing ratio in both end regions of the mask data in the Y-axis direction is lower than the printing ratio in regions other than the both end regions. It is a figure explaining an example of the change in a direction. The horizontal axis shows the nozzle number in the sub-scanning direction, and the vertical axis shows the amount of ink adhered.

As shown in FIG. 7, in the regions at both ends of the mask data in the sub-scanning direction, the printing rate is lower than in the regions other than the regions at both ends, so that the amount of ink adhered is small. The region at both ends of the mask data corresponds to the region at the end of the carriage, and the irradiation time of ultraviolet light by the irradiation unit becomes long, so that the image recorded on the paper using this region tends to have high gloss. By reducing the amount of ink adhered in the regions at both ends of the mask data, the gloss of the image can be lowered, and the high-gloss components can be offset to make the uneven gloss inconspicuous.

<Action and effect of recording device 10>
As described above, in the present embodiment, in the sub-scanning direction, the length of one cycle is L1 and the number of effective pixels changes by 74 cycles, and the length of one cycle is L2. The liquid discharge unit and the first and second drive units are controlled based on the mask data in which the printing rate changes with the two periodic components of the second periodic component in which the number of effective pixels changes by the period.

Thereby, the gloss unevenness of two or more kinds of periodic components is overlapped and offset in the sub-scanning direction, so that the gloss unevenness can be made inconspicuous.

In the above-described embodiment, the mask data in which the printing rate changes in the first and second periodic components is exemplified, but the mask data in which the printing rate changes in the periodic components of three or more cycles can also be used. good. It is more preferable that the number of types of periodic components is increased, because uneven gloss can be made inconspicuous.

Further, in the above-described embodiment, the configuration of the recording device 10 for recording an image on impermeable paper with ultraviolet curable ink has been exemplified, but the present invention is not limited thereto. The present embodiment can also be applied to a recording device that records an image on permeable paper with an ink that does not have ultraviolet curability. Here, the permeable paper means a paper on which ink easily penetrates.

With permeable paper, for example, when the carriage moves in the positive direction of the X-axis to record an image, and when the carriage moves in the negative direction of the X-axis to record an image, ink penetrates into the paper. The speed may be different. As a result, unevenness may occur in the state where the inks overlap on the paper, particularly in the sub-scanning direction, and density unevenness may occur in the image on the paper.

In such a case, by using mask data in which the printing ratio changes with two or more periodic components, the density unevenness of two or more periodic components is overlapped and offset in the sub-scanning direction, and the density unevenness is made inconspicuous. be able to.

Further, in the present embodiment, the printing ratio in the both end regions of the mask data in the sub-scanning direction is lower than the printing ratio in the regions other than the both end regions. In the end region of the carriage corresponding to the region at both ends of the mask data, the irradiation time of ultraviolet light by the irradiation unit tends to be long, and the gloss tends to be high. By lowering the printing rate, it is possible to reduce the amount of ink adhered in the edge region of the mask data to lower the gloss, cancel out the high gloss component, and make the uneven gloss inconspicuous. Similarly, in a recording device that records an image on permeable paper with an ink that does not have ultraviolet curability, density unevenness can be made inconspicuous.

[Second Embodiment]
Next, the recording device 10a according to the second embodiment will be described. The same component numbers as those described in the first embodiment are designated by the same part numbers, and duplicate explanations will be omitted as appropriate.

In the present embodiment, the head unit is divided into a plurality of blocks in the sub-scanning direction, and the head is recorded on paper while complementing the pixel area between different blocks for each relative movement in the main scanning direction. It controls the unit and the first and second drive units.

8A and 8B are views for explaining an example of a recording method by the recording device 10a, FIG. 8A is a diagram showing a division example of a head unit, and FIG. 8B is a diagram showing pixel complementation.

FIG. 8A shows a recording head group 300K in the head unit 300. FIG. 8A shows how the recording head group 300K is divided into three blocks, a first block 81, a second block 82, and a third block 83 in the sub-scanning direction (Y-axis direction).

FIG. 8B shows nine 3 × 3 pixel areas of the image recorded on the paper. The numerical value displayed in each pixel area represents the order in which the ink adheres to each block for each relative movement in the main scanning direction (X-axis direction).

For example, the first block 81 adheres ink to the pixel area displaying "1" in the first relative movement in the X-axis direction. Next, the second block 82 adheres ink to the pixel region displaying "2" in the second relative movement in the X-axis direction. The third block 83 adheres ink to the pixel area displaying “3” in the third relative movement in the X-axis direction.

In this way, the recording device 10a can record an image on paper so that the pixel area is complemented between different blocks for each relative movement in the main scanning direction. Although only the recording head group 300K is illustrated in FIG. 8, the same applies to the recording head groups 300C, 300M and 300Y of other colors.

Further, the recording method shown in FIG. 8 is an example and is not limited thereto. The method of dividing the blocks in the head unit 300, the pixel area to which the ink adheres to each block, and the order can be appropriately changed.

<Action and effect of recording device 30a>
As described above, in the present embodiment, the head unit is divided into a plurality of blocks in the sub-scanning direction, and an image is printed on paper while complementing the pixel areas between the different blocks for each relative movement in the main scanning direction. The head unit and the first and second drive units are controlled so as to record. This makes it possible to improve the quality of the image recorded on the paper as compared with the case where ink is adhered to the same pixel area in different blocks.

The other effects are the same as those described in the first embodiment.

Although the preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the specific embodiment, and is within the scope of the gist of the embodiment of the present invention described in the claims. Various modifications and changes are possible.

The embodiment also includes a liquid discharge method. For example, the liquid discharge method includes a liquid discharge step of discharging liquid to a recording medium by a liquid discharge unit having a plurality of nozzles arranged in a sub-scanning direction, and the sub-scanning of a carriage holding the liquid discharge unit and the recording medium. An image on the recording medium based on a first drive step of relative movement in the direction, a second drive step of relative movement of the carriage and the recording medium in the main scanning direction intersecting the sub-scanning direction, and predetermined mask data. The liquid discharge step and the control step for controlling the first and second drive steps are performed so as to record the above, and in the control step, the liquid is adhered per unit area of the recording medium. The printing rate indicating the ratio to be made is controlled based on the mask data in which the printing rate is changed by two or more periodic components in the sub-scanning direction. Such a liquid discharge method may be realized by a circuit such as a CPU and an LSI, an IC card, a single module, or the like.

In addition, the numbers such as the ordinal number and the quantity used in the description of the embodiment are all exemplified for concretely explaining the technique of the present invention, and the present invention is not limited to the exemplified numbers. Further, the connection relationship between the components is exemplified for concretely explaining the technique of the present invention, and the connection relationship for realizing the function of the present invention is not limited to this.

Further, the division of blocks in the functional block diagram is an example, and even if a plurality of blocks are realized as one block, one block is divided into a plurality of blocks, and / or some functions are transferred to another block. good. Further, the functions of a plurality of blocks having similar functions may be processed by a single hardware or software in parallel or in a time division manner.

Further, each function of the embodiment described above can be realized by one or a plurality of processing circuits. Here, the "processing circuit" as used herein is a processor programmed to perform each function by software, such as a processor implemented by an electronic circuit, or a processor designed to execute each function described above. It shall include devices such as ASIC (Application Specific Integrated Circuit), DSP (digital signal processor), FPGA (field programmable gate array) and conventional circuit modules.

10 Recording device (example of liquid discharge device)
12 Image processing unit 14 Recording unit 22 Irradiation drive unit 23 1st drive unit 24 2nd drive unit 28 Recording control unit 281 Mask setting unit 282 Mask storage unit 283 Mask processing unit 3 Controller unit 30 Control unit 31 Unit control circuit 32 Memory 33 CPU
34 I / F
60 Mask data 200 Carriage 300 Head unit 301, 302, 302 Recording head 400a, 400b Irradiation unit (example of irradiation unit)

JP-A-2017-507532

Claims (5)

A carriage that holds a liquid ejection unit that ejects liquid from multiple nozzles arranged in the sub-scanning direction to the recording medium.
A first drive unit that relatively moves the carriage and the recording medium in the sub-scanning direction, and
A second drive unit that moves the carriage and the recording medium relative to each other in the main scanning direction intersecting the sub-scanning direction.
It has a liquid discharge unit and a control unit that controls the first and second drive units so as to record an image on the recording medium based on predetermined mask data.
The control unit controls a liquid ejection device based on the mask data in which the printing rate indicating the ratio of the liquid adhering to the unit area of the recording medium changes with two or more periodic components in the sub-scanning direction. .. The carriage further comprises an irradiation unit that irradiates the liquid with light.
The liquid discharge device according to claim 1, wherein the control unit further controls irradiation of the light by the irradiation unit. The liquid ejection device according to claim 1 or 2, wherein the printing ratio in both end regions of the mask data in the sub-scanning direction is lower than the printing ratio in regions other than the both end regions. The liquid discharge unit is divided into a plurality of blocks in the sub-scanning direction.
The control unit performs the liquid ejection unit and the first and first units so as to record an image on the recording medium while complementing pixel regions between different blocks for each relative movement in the main scanning direction. 2. The liquid discharge device according to any one of claims 1 to 3, which controls the drive unit. A liquid ejection process that ejects liquid to a recording medium by a liquid ejection unit having a plurality of nozzles arranged in the sub-scanning direction, and a liquid ejection process.
A first driving step of moving the carriage holding the liquid discharge portion and the recording medium relative to each other in the sub-scanning direction.
A second drive step of moving the carriage and the recording medium relative to each other in the main scanning direction intersecting the sub-scanning direction.
A control step for controlling the liquid discharge step and the first and second drive steps is performed so as to record an image on the recording medium based on predetermined mask data.
In the control step, a liquid ejection method in which a printing rate indicating a ratio of the liquid adhering to a unit area of the recording medium is controlled based on the mask data in which two or more periodic components change in the sub-scanning direction.

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