JP2011115965A - Printer and printing method - Google Patents

Abstract

An appropriate printed matter is provided.
A head for discharging a coating ink for coating a medium, and an electromagnetic wave curable ink for image formation having a surface tension lower than the surface tension of the coating ink to the medium, and the electromagnetic wave for image formation Irradiating an electromagnetic wave to the curable ink to cure the electromagnetic wave curable ink for image formation; and when performing printing, the coating ink is ejected to coat the medium, and then the image forming An image is formed by ejecting electromagnetic wave curable ink to form an image, and then irradiating the electromagnetic wave to cure the electromagnetic wave curable ink for image formation. A first region where the image-forming electromagnetic curable ink is ejected on the coating ink, and the image-forming electromagnetic wave without ejecting the coating ink. To have a second region which is of ink ejected.
[Selection] Figure 4

Description

  The present invention relates to a printing apparatus and a printing method.

Printing apparatuses having a head that ejects ink toward a medium are already well known. As such a printing apparatus, for example, an ink jet printer is known. In addition, some of the printing apparatuses use an electromagnetic wave curable ink that is cured when irradiated with an electromagnetic wave such as ultraviolet rays. A curing unit that cures the ink is provided.

JP 2009-184206 A

By the way, in the above-described printing apparatus, the electromagnetic wave curable ink discharged toward the medium penetrates deep into the medium during printing, and the electromagnetic wave curable ink penetrated deeply is not properly irradiated with electromagnetic waves. In some cases, the electromagnetic wave curable ink does not cure properly. In particular, when a medium having ink permeability (for example, high-quality paper) is used as the medium, the above phenomenon is remarkable. In such a case, an appropriate printed matter may not be obtained due to bleeding of the electromagnetic wave curable ink.

This invention is made | formed in view of this subject, The place made into the objective is to provide a suitable printed matter.

The main present invention is a head for discharging a coating ink for coating a medium and an electromagnetic wave curable ink for image formation having a surface tension lower than the surface tension of the coating ink to the medium;
A curing part for irradiating the electromagnetic wave curable ink for image formation with electromagnetic waves to cure the electromagnetic wave curable ink for image formation;
When printing,
After causing the head to execute a first ejection process for ejecting the coating ink and coating the medium, the image-forming electromagnetic curable ink is ejected onto the medium coated with the coating ink. Causing the head to execute a second ejection process for forming
Thereafter, a controller that causes the curing unit to perform a curing process for irradiating the electromagnetic wave curable ink for image formation discharged on the medium with the electromagnetic wave and curing the electromagnetic wave curable ink for image formation,
An image forming area on the medium on which the image is formed includes a first area in which the electromagnetic wave curable ink for image formation is ejected on the coating ink and the image forming area without ejecting the coating ink. So as to have a second region where the electromagnetic wave curable ink is ejected,
A controller for causing the head to execute the first discharge process and the second discharge process;
It is a printing apparatus characterized by having.
Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

1 is a block diagram of a printer 1 according to an embodiment. 1 is a schematic sectional view of a printer 1. 4 is a flowchart for explaining a printing operation of the printer 1. It is a conceptual diagram for demonstrating the relationship between an image formation area | region and a coating area | region.

  At least the following will be made clear by the description of the present specification and the accompanying drawings.

A head for discharging a coating ink for coating a medium, and an electromagnetic wave curing ink for image formation having a surface tension lower than the surface tension of the coating ink to the medium;
A curing part for irradiating the electromagnetic wave curable ink for image formation with electromagnetic waves to cure the electromagnetic wave curable ink for image formation;
When printing,
After causing the head to execute a first ejection process for ejecting the coating ink and coating the medium, the image-forming electromagnetic curable ink is ejected onto the medium coated with the coating ink. Causing the head to execute a second ejection process for forming
Thereafter, a controller that causes the curing unit to perform a curing process for irradiating the electromagnetic wave curable ink for image formation discharged on the medium with the electromagnetic wave and curing the electromagnetic wave curable ink for image formation,
An image forming area on the medium on which the image is formed includes a first area in which the electromagnetic wave curable ink for image formation is ejected on the coating ink and the image forming area without ejecting the coating ink. So as to have a second region where the electromagnetic wave curable ink is ejected,
A controller for causing the head to execute the first discharge process and the second discharge process;
A printing apparatus comprising:
According to such a printing apparatus, it is possible to provide an appropriate printed matter.

In addition, the controller
The image forming area includes a plurality of the first areas and a plurality of the second areas, and the first areas and the second areas are alternately arranged.
The first ejection process and the second ejection process may be performed by the head.

In such a case, it becomes possible to provide a more appropriate printed matter.

Further, the curing part is a main curing part for main curing the electromagnetic wave curable ink for image formation,
Separately from the main curing part, the electromagnetic wave curable ink for image formation is irradiated with an electromagnetic wave to temporarily cure the electromagnetic wave curable ink for image formation,
The controller is
When printing,
Causing the head to perform the first ejection process, and then causing the head to perform the second ejection process,
Then, after the electromagnetic wave curable ink for image formation discharged on the medium is irradiated with the electromagnetic wave, the temporary curing process for temporarily curing the electromagnetic wave curable ink for image formation is performed on the temporary curing unit. The main curing process for main curing the electromagnetic wave curable ink for image formation may be performed by the main curing unit.
In such a case, it is possible to appropriately suppress deterioration of the image quality of the image.

The coating ink is an electromagnetic wave curable ink for coating,
The controller is
When printing,
First temporary curing in which the electromagnetic wave curable ink for coating that has been ejected onto the medium is irradiated with the electromagnetic wave to temporarily cure the electromagnetic wave curable ink for coating after the head performs the first ejection process. Processing the pre-curing part,
Thereafter, the second ejection process is performed on the head, and then the second temporary curing process for temporarily curing the electromagnetic wave curable ink for image formation is performed on the temporary curing unit.
Thereafter, the main curing process may be performed by the main curing unit.
In such a case, it is possible to more appropriately suppress the deterioration of the image quality of the image.

Next, a first discharge process for coating the medium by discharging a coating ink, and image formation having a surface tension lower than the surface tension of the coating ink on the medium coated with the coating ink Performing a second ejection process for ejecting the electromagnetic wave curable ink for forming an image,
Irradiating the electromagnetic wave curable ink for image formation ejected on the medium with the electromagnetic wave, and performing a curing process for curing the electromagnetic wave curable ink for image formation;
A printing method comprising:
When performing the first discharge process and the second discharge process,
An image forming area on the medium on which the image is formed includes a first area in which the electromagnetic wave curable ink for image formation is ejected on the coating ink and the image forming area without ejecting the coating ink. The printing method, wherein the first discharge process and the second discharge process are performed so as to have a second region where the electromagnetic wave curable ink is discharged.
According to such a printing method, it is possible to provide an appropriate printed matter.

=== Overview of Printer 1 ===
<<< Configuration of Printer 1 >>>
As an example of the printing apparatus, an ink jet printer (hereinafter referred to as printer 1) is taken as an example, and an embodiment will be described using a printing system in which the printer 1 and the computer 60 are connected.

FIG. 1 is a block diagram of the overall configuration of the printer 1 according to the present embodiment. FIG. 2 is a schematic sectional view of the printer 1. Print command (print data) from computer 60 as an external device
The printer 1 that has received the signal is sent to each unit (conveyance unit 20) by the controller 10.
The head unit 30 and the ultraviolet irradiation unit 40) are controlled to form an image on the paper S. Further, the detector group 50 monitors the situation in the printer 1, and the controller 10 controls each unit based on the detection result.

The controller 10 is a control unit for controlling the printer 1. The interface unit 11 is for transmitting and receiving data between the computer 60 as an external device and the printer 1. The CPU 12 is an arithmetic processing unit for controlling the entire printer 1. The memory 13 is for securing an area for storing a program of the CPU 12, a work area, and the like. The CPU 12 controls each unit by a unit control circuit 14 according to a program stored in the memory 13.

The transport unit 20 feeds the paper S as an example of a medium in a predetermined direction (hereinafter referred to as a transport direction).
It is for making it convey. As illustrated in FIG. 2, the transport unit 20 includes an upstream transport roller 23 a and a downstream transport roller 23 b, and a belt 24. When a transport motor (not shown) rotates, the upstream transport roller 23a and the downstream transport roller 23b rotate, and the belt 24 rotates. The paper S fed by a paper feed roller (not shown) is conveyed by a belt 24 to a printable area (area facing the head). Belt 2
As the paper 4 transports the paper S, the paper S moves in the transport direction with respect to the head unit 30. The paper S that has passed through the printable area is discharged to the outside by the belt 24. The paper S being conveyed is electrostatically attracted or vacuum attracted to the belt 24.

The head unit 30 has a head 31 for ejecting ink onto paper. In the printer 1 shown in FIG. 2, a plurality of heads 31 that eject different inks toward the paper S are provided. A plurality of nozzles that are ink discharge portions are provided on the lower surface of each head 31. Each nozzle is provided with a pressure chamber (not shown) containing ink, and a driving element (for example, a piezo element) for discharging ink by changing the capacity of the pressure chamber. When the drive signal is applied to the drive element, the drive element is deformed, and the pressure chamber expands / contracts along with the deformation, and ink is ejected.

In the present embodiment, an electromagnetic wave curable ink that is cured by being irradiated with ultraviolet rays as an example of electromagnetic waves as ink (in general, ink is a concept including both water-based ink and oil-based ink). As an example, ultraviolet curable ink is used. The ultraviolet curable ink is an ink containing an ultraviolet curable resin, and is cured when a photopolymerization reaction occurs in the ultraviolet curable resin when irradiated with ultraviolet rays.

The printer 1 includes a clear ink Cl, which is one type of colorless and transparent ultraviolet curable ink,
Eight types of colored ultraviolet curable inks, namely black ink K, cyan ink C, magenta ink M, yellow ink Y, light magenta ink Lm, and light cyan ink L
c, orange ink O, and green ink G can be discharged.
Here, the eight kinds of colored ultraviolet curable inks play a role as image forming inks, but the clear ink Cl does not have such a function but functions as a coating ink for coating the paper S. (In other words, eight types of colored ultraviolet curable inks (hereinafter also simply referred to as colored inks) correspond to electromagnetic wave curable inks for image formation, and clear ink Cl is a coating ink (coating Corresponding to electromagnetic wave curable ink for use). That is, although details will be described later, the controller 1 of the printer 1 according to the present embodiment.
0 indicates that the head 31 performs the first discharge process of coating the paper S by discharging the clear ink Cl as the coating ink, and then the paper S coated with the clear ink Cl.
The head 31 is caused to execute a second process of discharging colored ink to form an image. In the present embodiment, any of the colored inks has a surface tension lower than the surface tension of the clear ink Cl (that is, the surface tension of any colored ink is lower than the surface tension of the clear ink. ing). The surface tension of the ink can be controlled by adjusting the amount of the surfactant added to the ink, and the surface tension of the clear ink and the colored ink according to the present embodiment is also controlled by this method. The height relationship is realized. More specifically, the surface tension of each colored ink is 25 mN / m or more and 30 mN / m.
Hereinafter, the surface tension of the clear ink is 35 mN / m or more and 40 mN / m or less (controlled so as to be). The reason why the clear ink Cl is ejected before the colored ink is ejected to form the image to coat the paper S, and the reason why the surface tension of the ink has the above-described height relationship will be described in detail later.

As shown in FIG. 2, nine heads 31 are provided for each of the clear ink Cl and the eight types of colored inks. More specifically, as the head 31, in order from the upstream side to the downstream side in the transport direction, the head 31 (Cl) that discharges the clear ink Cl, the head 31 (K) that discharges the black ink K, and cyan. A head 31 (C) that ejects ink C, a head 31 (M) that ejects magenta ink M, a head 31 (Y) that ejects yellow ink Y, and a head 31 (Lm) that ejects light magenta ink Lm And light cyan ink Lc
A head 31 (Lc) that discharges orange ink, a head 31 (O) that discharges orange ink O, and a head 31 (G) that discharges green ink G are provided.

The ultraviolet irradiation unit 40 is for irradiating the ink discharged by the head 31 toward the paper S with ultraviolet rays to cure the ink. The ultraviolet irradiation unit 40 includes a preliminary irradiation unit 41 (corresponding to a temporary curing unit) that irradiates the ink with ultraviolet rays and temporarily cures the ink, and a main irradiation unit 42 (curing unit) that irradiates the ink with ultraviolet rays and fully cures the ink. And corresponding to the main curing portion). The preliminary irradiation unit 41 and the main irradiation unit 42 are lamps that cure by irradiating the ink with ultraviolet rays (
For the preliminary irradiation unit 41, for example, an LED, for the main irradiation unit 42, for example, an LED
, Mercury lamp, metal halide lamp).
The preliminary irradiation unit 41 irradiates ultraviolet rays having a lower irradiation intensity than the main irradiation unit 42. As a result, the ink ejected from the head 31 is not completely cured by the ultraviolet rays irradiated by the preliminary radiating unit 41 (preliminary curing), but completely by the ultraviolet rays radiated by the main irradiation unit 42. It will be cured (main curing).

In the printer 1 of the present embodiment, a plurality of preliminary irradiation units 41 corresponding to each of the plurality of heads 31 are provided for irradiating each of the nine different types of ink ejected by the plurality of heads 31 described above. ing. More specifically, the head 31 (Cl) corresponds to the head 31 (Cl) that discharges the clear ink Cl in order from the upstream side to the downstream side in the transport direction.
) Preliminary irradiation unit 41 (Cl) for irradiating the clear ink Cl located on the downstream side as viewed from FIG.
Corresponding to the head 31 (K) that discharges the black ink K, the preliminary irradiation unit 41 (K) for irradiating the black ink K located downstream from the head 31 (K), and the cyan ink C Corresponding to the head 31 (C) that discharges the ink, a preliminary irradiation unit 41 (C) for irradiating the cyan ink C located on the downstream side when viewed from the head 31 (C), and the head 31 that discharges the magenta ink M. Corresponding to (M), a pre-irradiation unit 41 (M) for irradiating magenta ink M located downstream from the head 31 (M), and a head 31 for discharging yellow ink Y
Corresponding to (Y), a pre-irradiation unit 41 (Y) for irradiating yellow ink Y located downstream from the head 31 (Y), and a head 31 (L) that ejects light magenta ink Lm.
m) and light magenta ink Lm located downstream from the head 31 (Lm)
Corresponding to the head 31 (Lc) that discharges the light cyan ink Lc, and for irradiating the light cyan ink Lc located downstream from the head 31 (Lc). The preliminary irradiation unit 41 (Lc) corresponds to the head 31 (O) that discharges the orange ink O, and the preliminary irradiation unit 41 (irradiates the orange ink O positioned downstream from the head 31 (O). O) and a pre-irradiation unit 41 (G) for irradiating the green ink G, which corresponds to the head 31 (G) that discharges the green ink G and is located downstream from the head 31 (G). Is provided. In addition, only one main irradiation unit 42 is provided on the most downstream side in the transport direction.

<<< Operation of Printer 1 >>>
By the way, the printer 1 according to the present embodiment has a large number of print modes. For example, a print mode that prints a color image using cyan, magenta, and yellow ink (
Hereinafter, it is referred to as a first printing mode), a printing mode in which a color image is printed using all colored inks (hereinafter referred to as a second printing mode), and the like. All of the nine heads 31 and the nine preliminary irradiation units 41 described above are not always used, and which head 31 and the preliminary irradiation unit 41 are used depends on the printing mode. It will be. That is, when printing is performed in the first print mode, the head 31 that ejects three colored inks corresponding to cyan, magenta, and yellow inks and the three preliminary irradiation units 41 that correspond to these heads operate.
When printing is performed in the second printing mode, the heads 31 that discharge eight colored inks and the eight preliminary irradiation units 41 corresponding thereto are operated. In the present embodiment, the head 31 (Cl) that discharges the clear ink Cl in any printing mode.
And the preliminary irradiation part 41 (Cl) corresponding to this operates.

Hereinafter, the printing operation of the printer 1 will be described with reference to FIGS. 3 and 4 by taking the operation when printing in the first printing mode is performed as an example. FIG. 3 is a flowchart for explaining the printing operation of the printer 1. FIG. 4 is a conceptual diagram for explaining the relationship between the image forming area and the coating area. Various operations of the printer 1 when printing is performed are mainly realized by the controller 10. In particular, this embodiment is realized by the CPU 12 processing a program stored in the memory 13. And this program is comprised from the code | cord | chord for performing the various operation | movement demonstrated below.

When receiving the print data, the controller 10 feeds the paper S onto the belt 24 (step S1).

The paper S is conveyed by the belt 24 without stopping at a constant speed, and eventually the head 31 is used.
Opposite (Cl). At this time, the controller 10 causes the head 31 (Cl) to execute a clear ink discharge process (corresponding to the first discharge process) for discharging the clear ink Cl to coat the paper S (step S3). Next, the controller 10 irradiates the clear ink Cl discharged on the paper S with ultraviolet rays to perform a clear ink temporary curing process (corresponding to the first curing process) to temporarily cure the clear ink Cl, and the preliminary irradiation unit 41 ( Cl) (Step S5, during which the paper S is being transported).

Next, the controller 10 causes the head 31 to execute a colored ink ejection process (corresponding to the second ejection process) for ejecting the colored ink onto the paper S coated with the clear ink to form an image, and then to the paper S. The pre-irradiation unit 41 is caused to execute a colored ink temporary curing process (corresponding to the temporary curing process and the second temporary curing process) for irradiating the discharged colored ink with ultraviolet rays to temporarily cure the colored ink. More specifically, the controller 10 first causes the head 31 (C) to execute cyan ink ejection processing for ejecting cyan ink C onto the paper S (step S7).
). Next, the controller 10 irradiates the cyan ink C with ultraviolet rays, and the cyan ink C
The preliminary irradiating unit 41 (C) is caused to perform a cyan ink temporary curing process for temporarily curing (step S9). Thereafter, the controller 10 sequentially turns the head 31 (M) and the preliminary irradiation unit 41 (
M), controlling the head 31 (Y) and the preliminary irradiation unit 41 (Y) to perform magenta ink ejection processing,
A magenta ink temporary curing process, a yellow ink ejection process, and a yellow ink temporary curing process are executed (steps S11, S13, S15, and S17, where ink ejection and preliminary irradiation are completed).

After the pre-irradiation is completed, the controller 10 performs a main curing process in which the ink ejected onto the medium (in this embodiment, the clear ink and the three types of colored inks) is irradiated with ultraviolet rays to fully cure the ink. The main irradiation unit 42 is caused to execute (step S19). As a result, printing of the image on the paper S is completed, and the paper S is discharged to the outside (step S).
21).

In the present embodiment, as shown in FIG. 4, the controller 10 does not coat the entire area on the paper S, but applies the coating corresponding to the image forming area where the image is formed. In the left diagram of FIG. 4, the image forming area is represented by a right-upward oblique line portion, and the coating area to be coated is represented by a right-down oblique line portion. As is apparent from this drawing, in the present embodiment, the coating area is the image forming area itself.

However, when these regions are viewed microscopically, as shown in the right diagram of FIG. 4, there are regions where an image is formed without being coated in the image forming region. The right diagram in FIG. 4 is a diagram in which a part of the left diagram in FIG. 4 is greatly enlarged, and shows the state of ink at the pixel level. Each circle schematically represents each pixel (or ink ejected to the pixel), and among these, the black circle is a first area as an example of a first area where colored ink is ejected onto the clear ink Cl. Pixels and white circles respectively indicate second pixels as an example of a second region in which colored ink is ejected without clear ink Cl being ejected.

As is clear from this figure, the controller 10 according to the present embodiment includes an image forming area on the paper S on which an image is formed, a first pixel in which colored ink is ejected on the clear ink Cl,
The head 31 is caused to execute the above-described clear ink discharge processing and color ink discharge processing so as to have the second pixel from which the colored ink is discharged without discharging the clear ink Cl. In addition, the controller 10 includes a clear ink so that the image forming region includes a plurality of the first pixels and a plurality of the second pixels, and the first pixels and the second pixels are alternately arranged. The ejection process and the color ink ejection process are executed by the head 31.

In other words, the controller 10 (head 31) first discharges the clear ink Cl sparsely (thinned out) in the clear ink discharge process. In the present embodiment, the clear ink Cl is not discharged and the clear ink Cl is not discharged to the adjacent pixel (corresponding to the second pixel) adjacent to the pixel (corresponding to the first pixel) from which the clear ink Cl is discharged. Clear so that the clear ink Cl is ejected to an adjacent pixel (corresponding to the first pixel) adjacent to the pixel (corresponding to the second pixel) (that is, the ejected clear ink forms a checkered pattern). Ink C
l is discharged. Then, the controller 10 (head 31) ejects colored ink to the first pixel and the second pixel in the subsequent colored ink ejection processing.

In the present embodiment, information received from the computer 60 and information on the image forming area (
In other words, the controller 10 determines the coating region (in other words, the pixel that ejects the clear ink Cl) based on the print data having information on which pixel the colored ink is ejected). However, the present invention is not limited to this, and the computer 60 determines the coating area based on the print data, and the determined coating area information is sent to the printer 1 together with the print data. It is good.

=== Effectiveness of Printer 1 According to the Present Embodiment ===
As described above, the printer 1 according to the present embodiment includes the clear ink Cl for coating that coats the paper S, and the colored ink for image formation having a surface tension lower than the surface tension of the clear ink Cl. A head 31 for discharging the paper S, a main irradiation unit 42 for irradiating the colored ink with ultraviolet rays to cure the colored ink, and a clear ink for coating the paper S by discharging the clear ink Cl during printing. After causing the head 31 (Cl) to perform the ejection process, the head 31 is caused to perform the colored ink ejection process for ejecting the colored ink onto the paper S coated with the clear ink Cl to form an image. The controller 10 causes the main irradiation unit 42 to perform a main curing process for irradiating the discharged colored ink with ultraviolet rays and main curing the colored ink. The image forming area on the paper S on which the image is formed has a first pixel in which the colored ink is ejected on the clear ink Cl and a second pixel in which the colored ink is ejected without ejecting the clear ink Cl. As described above, the controller 10 causes the head 31 to execute the clear ink discharge process and the color ink discharge process. This makes it possible to provide an appropriate printed material.

The above will be described while comparing the printer 1 according to the present embodiment and the printer 1 according to the comparative example. The controller 10 causes the head 31 to execute colored ink ejection processing for ejecting colored ink onto paper to form an image, and then irradiates the colored ink ejected onto the paper S with ultraviolet rays to fully cure the colored ink. The printer 1 according to the comparative example is the same as the printer 1 according to this embodiment in that the main curing process is performed by the main irradiation unit 42. However, the printer 1 according to the comparative example is not provided with the head 31 (Cl) that discharges the clear ink Cl for coating onto the paper S, and the printer 1 forms an image by discharging colored ink. The clear ink Cl is not discharged before the paper S is coated. For this reason, the printer 1 according to the comparative example may have the problems described below.

That is, during printing, the colored ink discharged onto the paper S in the colored ink discharge process penetrates deep into the paper S (that is, deep in the thickness direction of the paper) and penetrates deeply in the main curing process. The ink may not be properly irradiated with ultraviolet rays, and the colored ink may not be cured properly (particularly when using a medium having ink permeability (for example, high-quality paper), Is). In such a case, the image quality of the image may be deteriorated due to a problem caused by poor curing of the colored ink (such as bleeding of the colored ink). Furthermore, due to poor curing of the colored ink, there may be a problem that an odor peculiar to the ultraviolet curable ink remains. Thus, in the printer 1 according to the comparative example, an appropriate printed matter may not be obtained.

In contrast, in the present embodiment, the clear ink Cl having a surface tension higher than the surface tension of the colored ink is ejected to coat the paper S, and then the paper S coated with the clear ink Cl is cleared. An image is formed by discharging colored ink having a surface tension lower than that of the ink Cl. For this reason, the effect of the clear ink Cl blocking the colored ink prevents the colored ink from penetrating deeply into the paper S (and the occurrence of a phenomenon in which ultraviolet rays are not appropriately irradiated to the colored ink is suppressed). Therefore, problems caused by poor curing of colored ink (such as bleeding of colored ink) are suppressed, and deterioration of the image quality of the image is suppressed.

Further, since the coating is formed with the clear ink Cl having a higher surface tension, the clear ink Cl does not penetrate into the paper S as much as the colored ink in the comparative example. Therefore, the occurrence of problems due to the clear ink Cl penetrating deep into the paper S is also suppressed.
Degradation of the image quality is suppressed.

Further, since the colored ink having a lower surface tension is discharged onto the coated paper S, so-called repellency (aggregation unevenness, that is, a phenomenon in which the ink aggregates due to the influence of the high surface tension occurs, the ink is agglomerated. In other words, the occurrence of unevenness and the occurrence of unevenness are also suppressed, and the deterioration of the image quality of the image is also suppressed in this respect.

Further, from the viewpoint of not only the image quality but also the odor, this embodiment has an advantage as will be described below. In other words, the effect of the clear ink Cl blocking the colored ink prevents the colored ink from penetrating deeply into the paper S (and the occurrence of a phenomenon in which ultraviolet rays are not properly applied to the colored ink is suppressed). Therefore, the occurrence of the problem that the odor peculiar to the ultraviolet curable ink remains due to poor curing of the colored ink is suppressed.

Furthermore, since the coating is made with a clear ink Cl having a higher surface tension,
The clear ink Cl does not penetrate into the paper S as much as the colored ink in the comparative example. Therefore, when the clear ink Cl penetrates deep into the paper S, the ultraviolet light is not properly applied to the clear ink Cl and the odor remains. The occurrence of this will also be suppressed.

In this embodiment, the clear ink Cl is discharged sparsely (thinned out) (that is, the image forming area on the paper S on which the image is formed is the first in which the colored ink is discharged onto the clear ink Cl. This embodiment causes the head 31 to execute the clear ink discharge process and the color ink discharge process so as to have one pixel and the second pixel from which the colored ink is discharged without discharging the clear ink Cl. Have the following advantages. If the clear ink is not ejected sparsely (thinned out), but the clear ink is ejected so that a so-called clear ink solid image can be produced, the block effect described above (that is, the clear ink Cl is a colored ink). Although this is a perfect situation in terms of blocking effects, other problems can arise. That is, since the discharge amount of the clear ink is too large, the permeation effect of the clear ink into the paper S becomes too large, and the back-through occurs, which may cause problems in double-sided printing and the like. On the other hand, in the present embodiment, focusing on the fact that the clear ink Cl is ejected sparsely (thinned out), unlike the colored ink for image formation, the image itself does not collapse.
The clear ink Cl was discharged sparsely (thinned out). Therefore, the blocking effect can be appropriately exhibited while suppressing the occurrence of the defect (that is, the defect and the image quality degradation and odor problems can be alleviated in a balanced manner). From the above, according to the printer 1 according to the present embodiment, it is possible to provide an appropriate printed matter.

Further, in the present embodiment, the controller 10 includes the image forming area having a plurality of first pixels and a plurality of second pixels, and the first pixels and the second pixels are alternately arranged. As described above (more specifically, so that a checkered pattern is formed), the clear ink discharge process and the color ink discharge process are executed by the head 31. It is possible to suppress the occurrence of a portion where the image quality deterioration and the odor problem are biased and become prominent, and these problems can be alleviated in a more balanced manner. Therefore, it becomes possible to provide a more appropriate printed matter.

=== Other Embodiments ===
Although the above embodiments are mainly described with respect to a printing apparatus, disclosure of a printing method and the like is also included. The above-described embodiments are for facilitating understanding of the present invention, and are not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof. In particular, the embodiments described below are also included in the present invention.

Moreover, in the said embodiment, although the printing apparatus was actualized to the inkjet printer, it is not restricted to this, The present invention can also be applied to other printing apparatuses. In addition, a so-called line printer has been exemplified as an ink jet printer, but the present invention can also be applied to a so-called serial printer.

In the above embodiment, the ultraviolet curable ink is exemplified as the electromagnetic wave curable ink. However, the present invention is not limited to this. For example, an ink that is cured by an electromagnetic wave such as an electron beam, an X-ray, visible light, or infrared light may be used.

In the above embodiment, the paper S is taken as an example of the medium, but the present invention is not limited to this. For example, it may be a cloth.

In the above embodiment, the clear ink Cl is used as an example of the coating ink. However, the present invention is not limited to this. For example, white ink or metallic ink may be used.

In the above embodiment, when performing printing, the head 31 executes the clear ink discharge process, and then causes the head 31 to execute the color ink discharge process. Thereafter, the color ink discharged onto the paper S is applied to the color ink. The main irradiating unit 4 performs the main curing process in which the pre-irradiation unit 41 performs a temporary curing process of irradiating ultraviolet rays to temporarily cure the colored ink.
However, the present invention is not limited to this. For example, the provisional curing process is not executed, and therefore the present invention can be applied to the printer 1 without the preliminary irradiation unit 41.
However, when the temporary curing process is executed as in the above embodiment, the effect of mitigating the penetration of ink due to the increase in the viscosity of the ink by the temporary curing process (the ink is temporarily cured) is compared with the case where the temporary curing process is not performed. This will prevent the image quality from deteriorating (and the problem of remaining odor will be more appropriately suppressed).
.

In the above embodiment, when printing is performed, the clear ink ejection process is performed by the head 31 and then the clear ink Cl ejected on the paper S is irradiated with ultraviolet rays to temporarily remove the clear ink Cl. The preliminary irradiation unit 41 (Cl) executes the clear ink temporary curing process to be cured, and then the colored ink temporary curing process in which the colored ink is temporarily cured after the colored ink discharge process is performed by the head 31. However, the present invention is not limited to this. For example, there is no clear ink temporary curing process between the clear ink ejection process and the colored ink ejection process, and the printer 1 that performs the temporary curing process and the main curing process after the clear ink and the colored ink ejection process are all finished. The present invention can also be applied.
However, in the case where the clear ink temporary curing process is executed as in the above-described embodiment, the clear ink permeation is reduced due to the increase in the viscosity of the clear ink due to the clear ink temporary curing process, compared with the case where the clear ink temporary curing process is not executed. Since the effect (clear ink does not penetrate much due to temporary curing) is exerted, the image quality of the image is further prevented from degrading (and the problem of remaining odor remaining is more appropriately suppressed). )

1 Printer, 10 Controller, 11 Interface section, 12 CPU, 1
3 memory, 14 unit control circuit, 20 transport unit, 23a upstream transport roller, 23b downstream transport roller, 24 belt, 30 head unit, 31 head, 40 UV irradiation unit, 41 preliminary irradiation unit, 42 main irradiation unit, 50 Detector group

Claims (5)

A head for discharging a coating ink for coating a medium, and an electromagnetic wave curing ink for image formation having a surface tension lower than the surface tension of the coating ink to the medium;
A curing part for irradiating the electromagnetic wave curable ink for image formation with electromagnetic waves to cure the electromagnetic wave curable ink for image formation;
When printing,
After causing the head to execute a first ejection process for ejecting the coating ink and coating the medium, the image-forming electromagnetic curable ink is ejected onto the medium coated with the coating ink. Causing the head to execute a second ejection process for forming
Thereafter, a controller that causes the curing unit to perform a curing process for irradiating the electromagnetic wave curable ink for image formation discharged on the medium with the electromagnetic wave and curing the electromagnetic wave curable ink for image formation,
An image forming area on the medium on which the image is formed includes a first area in which the electromagnetic wave curable ink for image formation is ejected on the coating ink and the image forming area without ejecting the coating ink. So as to have a second region where the electromagnetic wave curable ink is ejected,
A controller for causing the head to execute the first discharge process and the second discharge process;
A printing apparatus comprising: The printing apparatus according to claim 1,
The controller is
The image forming area includes a plurality of the first areas and a plurality of the second areas, and the first areas and the second areas are alternately arranged.
A printing apparatus that causes the head to perform the first ejection process and the second ejection process. The printing apparatus according to claim 1 or 2,
The curing part is a main curing part for main curing the electromagnetic wave curable ink for image formation,
Separately from the main curing part, the electromagnetic wave curable ink for image formation is irradiated with an electromagnetic wave to temporarily cure the electromagnetic wave curable ink for image formation,
The controller is
When printing,
Causing the head to perform the first ejection process, and then causing the head to perform the second ejection process,
Then, after the electromagnetic wave curable ink for image formation discharged on the medium is irradiated with the electromagnetic wave, the temporary curing process for temporarily curing the electromagnetic wave curable ink for image formation is performed on the temporary curing unit. A printing apparatus characterized by causing the main curing unit to perform a main curing process for main curing the electromagnetic wave curable ink for image formation. The printing apparatus according to claim 3.
The coating ink is an electromagnetic wave curable ink for coating,
The controller is
When printing,
First temporary curing in which the electromagnetic wave curable ink for coating that has been ejected onto the medium is irradiated with the electromagnetic wave to temporarily cure the electromagnetic wave curable ink for coating after the head performs the first ejection process. Processing the pre-curing part,
Thereafter, the second ejection process is performed on the head, and then the second temporary curing process for temporarily curing the electromagnetic wave curable ink for image formation is performed on the temporary curing unit.
Thereafter, the main curing process is performed by the main curing unit. A first ejection process for coating the medium by ejecting a coating ink, and an electromagnetic wave curing for image formation having a surface tension lower than the surface tension of the coating ink on the medium coated with the coating ink. Executing a second ejection process for ejecting mold ink to form an image;
Irradiating the electromagnetic wave curable ink for image formation ejected on the medium with the electromagnetic wave, and performing a curing process for curing the electromagnetic wave curable ink for image formation;
A printing method comprising:
When performing the first discharge process and the second discharge process,
An image forming area on the medium on which the image is formed includes a first area in which the electromagnetic wave curable ink for image formation is ejected on the coating ink and the image forming area without ejecting the coating ink. The printing method, wherein the first discharge process and the second discharge process are performed so as to have a second region where the electromagnetic wave curable ink is discharged.

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