JP4639617B2 - Inkjet recording device - Google Patents

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus that records by shifting the center position of ink dots recorded by some recording heads from the center position of ink dots recorded by other recording heads.

In the field of printing, a gravure printing method and a flexographic printing method are usually used. However, in the gravure and flexographic printing methods, a plate making process is required.
For this reason, attention is being paid to an inkjet recording method that can reduce the cost of small-lot printing and perform printing on various recording media, without performing a plate making process, which is different from the conventional gravure / flexo printing method. Yes.

In particular, a photocurable inkjet recording apparatus using a photocurable ink such as a radical polymerization ink or a cationic polymerization ink can provide a recorded image comparable to a silver salt photograph (see Patent Document 1). .
JP 2001-310454 A

However, in the ink jet recording apparatus, when water-based ink or oil-based ink is used, most of the ink is absorbed by the recording medium. However, when photocurable ink is used, the ink is photocured on the recording medium. The mold ink remains without being absorbed. FIG. 11 is a schematic cross-sectional view when the center positions of all ink dots are recorded in an overlapping manner. When the yellow ink dot 1b is superimposed on the magenta, cyan and black ink dots 1a of the photo-curable ink and recorded on the recording medium 8, and this is observed from a micro viewpoint, the ink landing portion is excessively raised. Ink is cured in the This causes image variations, unevenness, and excessive glossiness, and this phenomenon is remarkable particularly in a recording region using a large amount of ink. Also, when using many types of ink, such as when using light magenta and light cyan as well as the basic colors yellow, magenta, cyan and black, the difference in image roughness, unevenness and glossiness Will occur more prominently.
Accordingly, an object of the present invention is to provide an ink jet recording apparatus capable of reducing the roughness of the surface of the recording medium and the difference in unevenness and suppressing the deterioration of the image quality.

In order to solve the above problems, an ink jet recording apparatus according to claim 1 is an ink jet recording apparatus that performs recording using an ink jet recording head in which an ejection port for ejecting ink that is cured by light irradiation is disposed. A plurality of recording heads for individually discharging yellow, magenta, cyan, and black inks, and inks having a hue similar to any of the inks and having a low recording density, and a light irradiation device that cures the discharged inks The one recording is performed such that the center position of the ink dot recorded by one of the plurality of recording heads is shifted from the center position of the ink dot recorded by the other plurality of recording heads. A control device for controlling the ejection of the head, wherein the one recording head is the same among the plurality of recording heads. Among a plurality of recording heads for ejecting ink of the hue, characterized in that it is a recording head for ejecting the lowest recording density ink.
According to the first aspect of the present invention, the center position of the ink dot recorded by one of the plurality of recording heads is the center position of the ink dot recorded by the other plurality of recording heads. It can be shifted and recorded. Further, when recording is performed using a plurality of inks of similar hues, it is possible to record by shifting the center position of the dot of the ink having the lowest recording density from the center position of the dots of the other ink.
According to a second aspect of the invention, in the ink jet recording apparatus according to claim 1, the center position of ink dots to be recorded by the one recording head, the ink to be recorded by the other of the plurality of recording heads The ejection control of the one print head is performed so that printing is performed at an intermediate position between the center position of the dot and the center position of the dot adjacent thereto.
According to the second aspect of the present invention, the center position of the ink dots recorded by one of the plurality of recording heads is changed from the center position of the ink dots recorded by the other plurality of recording heads. Further recording can be performed by shifting.
According to a third aspect of the present invention, in the ink jet recording apparatus according to the first or second aspect , the center positions of the ink dots recorded by the one recording head are recorded by the plurality of other recording heads. The ejection control of the one recording head is performed so that recording is performed at a position intermediate between the center position of the ink dot and the center position of the dot adjacent in the oblique direction.
According to the third aspect of the present invention, the center position of the ink dots recorded by the one recording head is positioned farthest from the center position of the ink dots recorded by the other recording heads. It can be recorded. The “oblique direction” means a direction between the main scanning direction and the sub-scanning direction.
According to a fourth aspect of the present invention, in the ink jet recording apparatus according to any one of the first to third aspects, from the central position of the ejection ports of the plurality of other recording heads to the central position of the adjacent ejection ports. The center position of the ejection port of the one recording head is disposed between them.
According to a fourth aspect of the present invention, in the ink jet recording apparatus according to any one of the first to third aspects, the center position of the ink dot recorded by the one recording head is set to a plurality of other dots. It becomes easy to record by shifting from the center position of the ink dots recorded by the recording head .

According to the first aspect of the present invention, it is possible to reduce the unevenness of the image recorded on the surface of the recording medium after the ink is cured. As a result, the glossiness is likely to be uniform, and the image quality can be improved. In addition, since the user can arbitrarily shift the overlap of the dots on which the ink is recorded, it is possible to obtain a glossiness and hue that is different from normal, so it is possible to select the glossiness and hue according to the user's request. There is an effect that can be done. In addition, since the center position of the ink dot having the lowest recording density among a plurality of inks of similar hues is recorded with a shift from the center position of the other ink dots, a clear image can be obtained by preventing the occurrence of color misregistration. There is an effect that it can be formed. The present invention is particularly effective in preventing the occurrence of color misregistration in a printing region having a high recording density such as characters printed in black or the like .
According to the second aspect of the present invention, the difference in unevenness on the surface of the recording medium after the ink is cured can be further reduced, so that the glossiness is easily uniformed and the image quality can be improved. Play.

According to the invention described in claim 3 , since the ink dots recorded by one recording head are recorded most distant from the ink dots recorded by other recording heads, the ink is cured particularly well. There is an effect that it is easy to obtain a uniform glossiness by reducing the difference in unevenness on the surface of the subsequent recording medium, and the image quality can be further improved.
According to the fourth aspect of the invention, recording is performed by shifting the center position of the ink dot recorded by one recording head from the center position of the ink dot recorded by another recording head by simple control. Therefore, it is possible to easily suppress the difference in unevenness on the surface of the recording medium, and it is possible to improve the image quality.

Embodiments of an ink jet recording apparatus according to the present invention will be described below with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples.
[First embodiment]
FIG. 1 is a schematic front view illustrating a main configuration of a recording unit of a serial head type inkjet recording apparatus when viewed from the sub-scanning direction B. FIG. This serial head type ink jet recording apparatus has a platen 2 on a flat plate that supports the non-recording surface (the back surface of the recording surface) of the recording medium 8, and transport rollers (not shown) are provided before and after the platen 2. Each is arranged. Each transport roller is rotated in a predetermined direction around the axis before and after the platen 2, and the recording medium 8 is transported in the sub-scanning direction B of the image recording unit as each transport roller rotates. The

Above the platen 2, an image recording unit having a carriage and a guide member for recording an image on the recording surface of the recording medium 8 is disposed. The image recording unit has a guide member (not shown) extending in the main scanning direction A, which is a direction orthogonal to the sub-scanning direction B, and the carriage 4 is supported on the guide member. The carriage 4 includes a yellow (Y) recording head 51, a magenta (M) recording head 52a, a cyan (C) recording head 52b, and a black (K) recording head 52c along the main scanning direction A. Are arranged and mounted. These recording heads have ink ejection openings on the side facing the recording medium 8. Ink tanks for storing yellow, magenta, cyan, and black inks are connected to the recording heads 51 and 52a to 52c, respectively (not shown).
Light irradiation devices 6a and 6b for curing ink landed on the recording medium are provided on both sides of the group of recording heads. The light used in the present embodiment includes electromagnetic waves such as ultraviolet rays, electron beams, X-rays, visible rays, and infrared rays. A phosphor may be used as the light source, but an ultraviolet light source is preferable in order to improve curing, and a mercury lamp, a metal halide lamp, a black light, a cathode tube, an LED (Light Emitting Diode), or the like can be used. The carriage 4 on which these are mounted is capable of scanning (moving back and forth) along the main scanning direction A while being guided by a guide member.

As shown in FIG. 2, a plurality of ejection ports 521 of the recording heads 52a to 52c are arranged in a line at equal intervals. On the other hand, the ejection ports 511 of the recording head 51a are arranged at equal intervals along the sub-scanning direction B so as to be arranged at intermediate positions between the ejection ports 521, 521,. A plurality are arranged in a shape.
The ink jet recording apparatus is provided with a control device 10a for controlling each drive unit as shown in FIG.
The control device according to the present embodiment includes an interface, a storage device such as a ROM, a CPU, and the like. The transport device 3, the carriage 4, the drive sources of the recording heads 51, 52a to 52c, the light irradiation device 6, the input device 9, and the like. It is connected to the.
The control device 10a expands a program stored in advance in a storage circuit in a predetermined work area, and executes various processes according to the program, whereby the carriage drive device 41, the recording heads 51, 52a to 52c, and the conveyance The device 3, the light irradiation device 6 and the like are controlled.
As shown in FIG. 3, the control device 10a, based on the output image from the input device 9 or the like, detects the magenta, cyan, and black inks that are obliquely adjacent from the center position of the magenta, cyan, and black ink dots. The carriage driving device 41, the recording heads 51, 52a to 52c, and the like are controlled in the main scanning direction A so that the center position of the yellow ink dot is recorded at an intermediate position to the center position of the dot. It is configured.

The ink used in the present embodiment may be a water-based ink, an oil-based ink, a photocurable ink, or the like. In particular, a photocurable ink that can be used for a wide range of recording media is preferable. As the photocurable ink, it is possible to use an ink containing a radical polymerizable compound, an ink containing a cationic polymerizable compound, or a hybrid ink in which these are mixed. It is also possible to add a photoinitiator or the like so that the curing reaction can proceed well.
As the recording medium 8 used in the present embodiment, plain paper, high-quality paper, fabric, etc., which is an absorbent recording medium, or plastic, resin film, metal, glass, etc., which is a non-absorbent recording medium, can be used.

The operation of the ink jet recording apparatus of this embodiment will be described.
Under the control of the control device 10a, the recording medium 8 is transported onto the platen 2 by the transport device 3 during image recording. As the recording medium 8 is conveyed, the carriage 4 is reciprocated in the main scanning direction A to eject ink from the ejection ports 511 and 521.

FIG. 4 is an enlarged top view of a part of the recording medium 8 landed with magenta, cyan and black inks and yellow ink according to the present invention. As shown in FIG. 4, the magenta, cyan, and black ink dots 1a are recorded by the ejection port 521, and the center positions of the magenta, cyan, and black ink dots 1a that are obliquely adjacent to each other. The center position of the yellow ink dot 1b is recorded by the ejection port 511 at a position intermediate between the two. The magenta, cyan and black ink and yellow ink recorded on the recording medium 8 are irradiated with light by the carriage 4 provided with the light irradiation devices 6a and 6b reciprocatingly under the control of the control device 10a. , Photocured. Thereby, an image is recorded on the recording medium 8.
As described above, in the sub-scanning direction B, the center position of the magenta, cyan, and black ink dots is shifted from the center position of the yellow ink dot, thereby recording on the recording medium of FIG. As is clear from the cross-sectional view of the ink, as compared with the case of FIG. 11, the bulge of the ink landing portion on the recording medium is alleviated to eliminate the roughness and unevenness of the image and form a smooth image. Become. In addition, as a result of less unevenness and roughness, an easy-to-see image having a uniform glossiness is formed.

The control device 10a does not necessarily record the center positions of the yellow ink dots at positions from the center positions of the magenta, cyan, and black ink dots to the center positions of adjacent dots in the oblique direction. There is no need to control.
As shown in FIG. 6, along the sub-scanning direction B, the center position of the yellow ink dot 1b is in the middle position between the center position of the cyan, magenta, and black ink dots 1a and the center position of the adjacent dots 1a. The same effect can also be obtained by controlling so that is recorded.

Further, as shown in FIG. 7, the yellow ink dot 1b is positioned at a middle position between the center position of the magenta, cyan and black ink dots 1a and the center position of the adjacent dots 1a along the main scanning direction A. The same effect can be obtained by controlling so that the center position is recorded.
The color of the ink ejected by the one recording head may be any color that is to be ejected by the plurality of recording heads, but the plurality of recording heads include a plurality of basic colors. In such a case, it is possible to further suppress the color misregistration of the image recorded on the recording medium by discharging the basic color having the highest brightness among the basic colors from the one recording head. Become.
In addition, when water-based ink or oil-based ink is used instead of photo-curing type ink, it is possible to obtain a uniform glossy feeling, and it is possible to prevent ink from overflowing in the dots. Ink bleeding and an increase in dot diameter can be suppressed, and the image quality can be improved.
[Second Embodiment]

  Next, a second embodiment of the ink jet recording apparatus according to the present invention will be described with reference to FIG. FIG. 8 is a schematic front view showing the main configuration of the recording unit of the serial head type inkjet recording apparatus when viewed from the sub-scanning direction B. FIG. However, the second embodiment is different from the first embodiment only in the image recording unit (see FIG. 1) in the first embodiment, and other configurations are the same as those in the first embodiment. In the second embodiment, description will be made centering on the image recording unit, and description of the same configuration as in the first embodiment will be omitted.

  The carriage 4 includes a light magenta (LM) recording head 53a, a light cyan (LC) recording head 53b, a yellow recording head 54a, a magenta recording head 54b, a cyan recording head 54c, and a black recording head 54d. Arranged along the scanning direction A are mounted. These recording heads have ink ejection openings on the side facing the recording medium 8. Ink tanks for storing light magenta, light cyan, yellow, magenta, cyan, and black ink are connected to the recording heads 53a, 53b, and 54a to 54d, respectively (not shown). Light irradiation devices 6a and 6b for curing ink landed on the recording medium are provided on both sides of the group of recording heads.

  As shown in FIG. 9, a plurality of ejection ports 541 of the recording heads 54a to 54d are arranged in a line at equal intervals. On the other hand, the ejection ports 531 of the recording heads 53a and 53b are equally spaced along the sub-scanning direction B so as to be arranged at intermediate positions between the ejection ports 541, 541,... Of the recording heads 54a to 54d. Are arranged in rows.

The light irradiation devices 6 a and 6 b provided with a light irradiation light source for irradiating the ink landed on the recording medium 8 are installed on both sides of the recording heads on both ends mounted on the carriage 4.
The ink jet recording apparatus is provided with a control device 10b and controls each drive unit as shown in FIG. Based on the output image from the input device 9 or the like, the control device 10b determines the center of the yellow, magenta, cyan, and black ink dots that are diagonally adjacent to the center position of the yellow, magenta, cyan, and black ink dots. The carriage drive device 41, the recording heads 53a and 53b, 54a to 54d, and the like are controlled in the main scanning direction A so that the center positions of the light magenta and light cyan ink dots are recorded at intermediate positions. It is configured as follows.

By discharging each ink under such a configuration, the yellow, magenta, and cyan in the oblique direction adjacent to the center position of the yellow, magenta, cyan, and black ink dots as in the first embodiment. The center positions of the light magenta and light cyan ink dots are recorded in the middle of the center positions of the black ink dots.
These inks are irradiated with light by reciprocating the carriage 4 provided with the light irradiation devices 6a and 6b under the control of the control device 10b, and are cured. As a result, an image is recorded on the recording medium 8.
When there are a plurality of recording heads that discharge inks of similar hues as described above, the center position of the dot of the ink having the lowest recording density is the center position of the ink dot having the lowest recording density among the inks of the same hue By recording from a different position, in addition to the same effects as in the first embodiment, it is possible to obtain the effect of preventing the occurrence of color misregistration in the image recorded on the recording medium.

  Also in the second embodiment, the yellow, magenta, and cyan adjacent from the center position of the yellow, magenta, cyan, and black ink dots along the sub-scanning direction B or along the main scanning direction A. The same effect as described above can be obtained by controlling the light magenta and light cyan ink dot center positions to be recorded at an intermediate position to the center position of the black ink dot.

  Further, as is apparent from the second embodiment, when there are a plurality of combinations of inks of similar hues such as light magenta and magenta and light cyan and cyan, the ink with the lowest recording density in all the combinations is selected. Assume that the center position of the dots is shifted from the center position of the ink dots having a high recording density.

In the configuration described above, the center position of the ink dot having the highest glossiness may be recorded while being shifted from the center position of the other ink dots. In this case, uniform gloss can be obtained in the image recorded on the recording medium.
In the above description, only the serial head type ink jet recording apparatus is mentioned. However, the present invention is not limited to this type, and the line head can be controlled by performing the same control in the line head type ink jet recording apparatus. The same effect as that of the ink jet recording apparatus can be obtained. In the case of the line head system, the “oblique direction” means a direction between the row direction of the ejection ports of each print head and the conveyance direction of the print medium perpendicular to the row direction.

FIG. 2 is a schematic front view illustrating a main configuration of a recording unit of a serial head type inkjet recording apparatus when viewed from the sub-scanning direction in the first embodiment. FIG. 2 is a schematic diagram illustrating an arrangement of ejection ports of each recording head used in the first embodiment. It is a functional block diagram of the ink jet recording apparatus in the first embodiment. FIG. 4 is an enlarged schematic top view of a portion of a recording medium landed with cyan, magenta, and black ink and yellow ink according to the present invention. It is a schematic sectional drawing of the ink which landed on the recording medium in 1st embodiment. It is a schematic sectional drawing of the ink which landed on the recording medium in 1st embodiment. It is a schematic sectional drawing of the ink which landed on the recording medium in 1st embodiment. FIG. 6 is a schematic front view illustrating a main configuration of a recording unit of a serial head type inkjet recording apparatus when viewed from a sub-scanning direction of a recording medium in a second embodiment. FIG. 10 is a schematic front view illustrating a main configuration of a recording unit of a serial head type inkjet recording apparatus when viewed from the sub-scanning direction in the second embodiment. It is a functional block diagram of the inkjet recording device in 2nd embodiment. It is a schematic sectional drawing of the ink which landed on the recording medium in a prior art.

Explanation of symbols

1 dot 2 platen 3 transport device 4 carriage 41 carriage drive device 51 recording head 511 ejection port 52 recording head 521 ejection port 53 recording head 531 ejection port,
54 Recording Head 541 Discharge Port 6 Light Irradiation Device 8 Recording Medium 9 Input Device 10 Control Device

Claims (4)

In an inkjet recording apparatus that performs recording using an inkjet recording head in which an ejection port that ejects ink that is cured by light irradiation is disposed.
A plurality of recording heads that individually discharge yellow, magenta, cyan, and black inks, and inks having a hue similar to any of the inks and having a low recording density ;
A light irradiation device for curing the discharged ink;
The one recording head so that the center position of the ink dots recorded by one of the plurality of recording heads is shifted from the center position of the ink dots recorded by the other plurality of recording heads. A control device for performing the discharge control;
With
The one recording head is a recording head that discharges an ink having the lowest recording density among a plurality of recording heads that discharge ink of the same hue among the plurality of recording heads. . The controller is
The center position of the ink dots recorded by the one recording head,
The ejection control of the one recording head is performed so that the recording is performed at an intermediate position between the center position of the ink dots recorded by the plurality of other recording heads and the center position of the adjacent dots. The inkjet recording apparatus according to claim 1 . The controller is
The center position of the ink dots recorded by the one recording head,
The ejection control of the one recording head is performed so that the recording is performed at an intermediate position between the center position of the ink dots recorded by the plurality of other recording heads and the center position of the dots adjacent in the oblique direction. The ink jet recording apparatus according to claim 1 or 2 , characterized in that Claims 1 to 3, characterized in that until the center position of the discharge port adjacent the center position of the discharge port of the other of the plurality of recording heads were arranged the center position of the discharge port of the one recording head The ink jet recording apparatus according to any one of the above.

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