JP2001301203A - Ink jet recording method and ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an ink jet recording method and an ink jet recorder in which a high quality smooth color image can be formed without causing any deterioration of image due to blur or cost increase. SOLUTION: In an ink jet recorder 20 performing recording by sticking dots of a plurality of colors of ink liquid drop onto a recording medium, density halftoning is employed for achromatic halftone representation and area halftoning is employed for chromatic halftone representation when achromatic ink and chromatic ink are used for halftone representation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ink jet recording method and an ink jet recording apparatus for performing recording by attaching dots of ink droplets on a recording medium.

[0002]

2. Description of the Related Art In recent years, ink-jet recording apparatuses have rapidly become widespread as output apparatuses for industrial use, office use, and personal use because of easy colorization of digital images.

Under such circumstances, application of the ink jet recording apparatus to printing is also expected. A typical example of printing is a silk screen printing method. In this method, a screen plate is prepared for each color used in the original image to be printed, and the printing paste is passed through the screen plate and directly transferred to a fabric for dyeing. However, this method requires a great deal of man-hours to produce a screen plate, and also requires the printing paste for each color used in the original image to be prepared by dye mixing. A cost problem has arisen.

In contrast to such a conventional printing method, the above-mentioned ink jet printing method controls the kind of ink provided in the apparatus by a digital signal and lands and forms small droplets of ink on a medium. Directly form an image. Therefore, there is no need to prepare a screen plate or a printing paste for each color, and the number of steps can be significantly reduced.

[0005]

By the way, the ink-jet type color forming method lands small droplets of ink on a cloth,
It is a method of forming. The gradation forming method in this case is area gradation. In the area gradation, in the case of printing, the dot diameter is different and the number of dots is constant.

On the other hand, in the case of ink jet, the dot diameter is constant and the number of dots per unit area is different. Therefore, in general, in the case of an ink jet, there is a graininess of dots (hereinafter, this graininess is called “roughness”).

In order to solve this problem, for example, Japanese Patent Application Laid-Open No. 59-201864 proposes means for forming a gradation by changing the dot diameter as in printing. In this method, a plurality of ink droplets are ejected to one pixel in accordance with the density of an image to be recorded for one pixel to form a dot. However, in this method, as the density becomes higher, the number of ink droplets to be ejected to one pixel increases, so that the printing operation requires time and the printing speed is reduced.
Further, the recording medium has a permissible ink amount limit. If an ink amount exceeding the permissible amount is formed in the same pixel, "bleeding" occurs.
This causes a problem of causing image deterioration.

As another means, Japanese Patent Application Laid-Open No. 9-210
As described in JP 402, the dye of the ink is the same,
There is a method of giving a density gradation by making only the density different. That is, the highlight portion is recorded with low-density ink (hereinafter, “light-color ink”) to make the roughness less noticeable, and the high-density portion is recorded with high-density ink (hereinafter, “dark-color ink”)
To record. According to this method, a method (multi-drop method) in which a plurality of droplets described above are used for the same pixel.
Without increasing the number of ejections to one pixel as in
Since a high density portion can be formed, a decrease in recording speed can be suppressed.

However, this method requires at least two heads, one for dark color ink and the other for light color ink, and there is a problem that the head mounting portion becomes large and the apparatus becomes large. Also, there is a problem that the cost is greatly increased due to the necessity of a large number of heads.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an ink jet recording method and an ink jet recording method capable of forming a high-quality color image without roughness without causing image deterioration or cost increase due to bleeding or the like. It is intended to realize the device.

[0011]

The present invention for solving the above-mentioned problems is as follows. (1) The invention according to claim 1 is an ink jet recording method for performing recording by adhering dots of ink droplets of a plurality of colors on a recording medium, wherein an achromatic ink and a chromatic ink are used. When performing gray scale expression using gray scale, achromatic color scale is expressed with density gray scale, and chromatic color scale is expressed with area gray scale.
This is an ink jet recording method characterized by the following.

According to a third aspect of the present invention, there is provided an ink jet recording apparatus for performing recording by adhering dots of ink droplets of a plurality of colors on a recording medium, wherein an achromatic ink and a chromatic ink are used. An ink jet recording apparatus characterized in that, when performing gradation expression by using, a gradation expression of an achromatic color is performed by a density gradation and a gradation expression of a chromatic color is performed by an area gradation.

The inventors of the present application have conducted intensive studies on the roughness of an image formed by ink-jet recording. As a result, the perception of roughness by human eyes is different in the gradation expression between chromatic colors and achromatic colors. Was found.

According to the present invention, when gradation expression is performed using achromatic ink and chromatic ink, gradation expression of achromatic color is performed by density gradation, and gradation expression of chromatic color is performed by area. Since the gradation is performed using the gradation, it is possible to perform the gradation expression suitable for each of the achromatic color and the chromatic color without causing roughness. As a result, a high-quality color image without roughness can be formed without causing image deterioration or cost increase due to bleeding or the like.

(2) In the density gradation in the above (1), it is desirable to change the number of dots to be printed per unit area and to change the dot density. (3) In the area gradation in the above (1) or (2), it is desirable to change the number of dots to be printed per unit area and to change the dot diameter.

(4) The invention according to claim 6 is an ink jet recording apparatus for performing recording by adhering dots of ink droplets of a plurality of colors on a recording medium, wherein an achromatic ink and a chromatic ink are used. When expressing gradation using, the achromatic color satisfies the following condition 1, and the chromatic color satisfies either the following condition 2 or condition 3. The ink jet recording apparatus is characterized in that expression is performed by density gradation and gradation expression when none of the conditions is satisfied is performed by area gradation.

The value of Lab shown here is:
It is a figure which shows the perceived chromaticity index defined in CIE1976 (Lab) space. Condition 1: achromatic color where L <40 Condition 2: chromatic color where L <55 Condition 3: The difference δE between the Lab of the finally formed image and the Lab of the ink itself forming the image is Chromatic color where δE> 60 The inventors of the present application have conducted intensive studies on the roughness of an image formed by inkjet recording, and as a result, the way in which the human eye perceives the roughness is the gradation between a chromatic color and an achromatic color. The expression was found to be different in Lab space.

According to the present invention, when gradation expression is performed using achromatic ink and chromatic ink, condition 1 is satisfied for achromatic color, and condition 2 or condition 2 is satisfied for chromatic color. The gradation expression when either one of the conditions 3 is satisfied is performed by the density gradation, and the gradation expression when none of the conditions is satisfied is performed by the area gradation. It is possible to perform gradation expression suitable for each of them without causing roughness. As a result, a high-quality color image without roughness can be formed without causing image deterioration or cost increase due to bleeding or the like.

(5) In the density gradation in (4), it is desirable to change the number of dots to be printed per unit area and to change the dot density. (6) In the area gradation in the above (4) or (5), it is desirable to change the number of dots to be printed per unit area and change the dot diameter.

(7) The invention according to claim 2 is an ink-jet recording method for performing recording by adhering dots of ink droplets of a plurality of colors on a recording medium, comprising an achromatic ink and a chromatic ink. When expressing tones using, the number of inks with different densities of achromatic colors is greater than the number of inks with different densities of any one of the chromatic colors, and the gradation expression of chromatic colors is This is an ink jet recording method characterized in that the method is performed with gradation.

According to a ninth aspect of the present invention, there is provided an ink jet recording apparatus for performing recording by adhering dots of ink droplets of a plurality of colors on a recording medium, wherein an achromatic ink and a chromatic ink are used. When performing gradation expression by using, the number of inks with different densities of achromatic colors is larger than the number of inks with different densities of any one of the chromatic colors, and the gradation expression of chromatic colors is expressed by area scale. And an ink jet recording apparatus.

The inventors of the present application have conducted intensive studies on the roughness of an image formed by ink-jet recording. As a result, the perception of roughness by human eyes is different in the gradation expression between chromatic colors and achromatic colors. Was found.

According to the present invention, when gradation is expressed using achromatic ink and chromatic ink, the number of inks having different achromatic color densities is determined by the density of any one of the chromatic colors. In addition to the number of different inks, the chromatic color gradation expression is performed by area gradation, so that gradation expression suitable for each of achromatic color and chromatic color can be performed without roughness. Will be possible. As a result, a high-quality color image without roughness can be formed without causing image deterioration or cost increase due to bleeding or the like.

(8) It is preferable that the chromatic colors of (7) have yellow, cyan and magenta as basic colors. (9) It is desirable to have red, blue and violet as special colors as the chromatic colors of the above (7) or (8).

(10) It is desirable to use the ink jet recording apparatus described in (1) to (9) for printing, since an extremely good result can be obtained in terms of eliminating roughness.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of the ink jet recording apparatus of the present embodiment.

RGB data or L supplied from outside
The ab data is subjected to predetermined color conversion or color separation in a color conversion processing unit 30 in the inkjet recording device 20, and is further subjected to error diffusion processing in an error diffusion processing unit 40.
Next, data conversion for the printer is performed by the data conversion unit for the printer 50, and dots of the ink droplets are attached to the recording medium 70 by the output unit 60 to perform image recording.

The operation (ink jet recording method) of the ink jet recording apparatus of this embodiment will be described below. The output unit 60 of the inkjet recording apparatus 20 includes a cyan ink (hereinafter, referred to as “C ink”), a magenta ink (hereinafter, referred to as “M ink”), a yellow ink (hereinafter, referred to as “Y ink”), and a dark black ink (hereinafter, referred to as “K ink”). Ink ").

Further, a combination of colors is selected from orange ink (hereinafter referred to as "O ink"), violet ink (hereinafter referred to as "V ink"), red ink (hereinafter referred to as "R ink"), and blue ink (hereinafter referred to as "B ink"). Was.

Further, a low-density light-color ink is provided for each color ink, and a cyan light-color ink (hereinafter referred to as “C2
Ink ”), magenta light color ink (hereinafter“ M2 ink ”), yellow light color ink (hereinafter“ Y2 ink ”),
Black light color ink (hereinafter “K2 ink”), orange light color ink (hereinafter “O2 ink”), violet light color ink (hereinafter “V2 ink”), red light color ink (hereinafter “R”)
2 ink ”) and blue light color ink (hereinafter“ B2 ink ”).

The color of the ink used here is CIE
The perceptual chromaticity index defined in the 1976 (Lab) space is in the following range. The values defined here are those obtained by printing at a recording density of 300 dots per 25.4 mm using a recording medium having an L value of 90 or more and an ab value of -40 to 40 or less. is there.

In this embodiment, SP62 (X-Rite Inc.) is used as a measuring instrument for measuring the perceived chromaticity index.
orporated).・ Normal (dark color) ink C ink: L = 40-50, a = -50-0, b = -5--40 M ink: L = 40-50, a = 50-80, b = -10- 20 Y ink: L = 75-80, a = -40-100, b = 50-90 K ink: L = 15-25, a = -10-10, b = -10-10 O ink: L = 65 -75, a = 30-50, b = 70-90 V ink: L = 35-45, a = 40-60, b = -40--20 R ink: L = 40-50, a = 50-70 B ink: B = 20 to 40 B ink: L = 35 to 45, a = 0 to 30, b = -5 to -40 Light color ink C2 ink: L = 60 to 70, a = -50 to 0, b =- 5-40 M2 ink: L = 60-70, a = 40-80, b = -15-20 Y2 ink: L = 80-85, a = -40-10, b = 50-90 K2 ink: L = 40-50, a = -10-10, b = -10-10 O2 ink: L = 75-85, a = 30-50, b = 70-90 V2 ink: L = 60-70, a = 40 -60, b = -40--20 R2 ink: L = 60-70, a = 50-70, b = 20-40 B2 ink: L = 60 to 70, a = 0 to 30, b = -5 to -40 In the case of performing gradation expression by density gradation, refer to
By applying the technique disclosed in Japanese Patent Publication No. 210402, ternarization is performed by using dark ink / light ink in addition to dot ON (dot formation) / dot OFF (dot non-formation).
In this case, the dot diameter was set to 85 μm in consideration of printing.

When area gradation is used for gradation expression, the technique described in Japanese Patent Application Laid-Open No. 59-201864 is applied.
A method in which one pixel is composed of three dots of ink droplets, that is, three types of different dot diameters can be formed. The dot diameter in this case is also 50 μm, 85 μm, 1
It was 40 μm.

Incidentally, as the ink jet recording apparatus,
The following three types of devices that operate differently were manufactured. Apparatus A: Apparatus that executes gradation expression only by changing the number of dots B Apparatus: Apparatus that performs gradation expression for both achromatic and chromatic colors by density gradation C apparatus: Performs achromatic color gradation expression by density gradation , A device that performs chromatic color gradation expression by area gradation D device: Achromatic color satisfies the following condition 1, and chromatic color satisfies either condition 2 or condition 3 below In this device, the gradation expression is performed by density gradation, and in other cases (neither Condition 2 nor Condition 3 is satisfied), the color gradation expression is performed by area gradation. Condition 1: achromatic color where L <40 Condition 2: chromatic color where L <55 Condition 3: The difference δE between the Lab of the finally formed image and the Lab of the ink itself forming the image is Chromatic color where δE> 60 FIG. 2 shows the state of the ink used in the experiment under the above conditions. In Examples 1 to 5, samples were produced using the C apparatus. On the other hand, in Comparative Example 1 and Comparative Example 2, samples were produced using the A apparatus. In Examples 6 to 15, samples were manufactured using the D apparatus. In Comparative Examples 3 and 4, samples were produced using the B apparatus.

A sample was prepared by using the above ink and apparatus, using Tiff Lab data as an image, and L = 20 to 90.
At a spacing of 10 and a and b at a spacing of 5 from -75 to 75, respectively, with a patch size of one square centimeter.

Then, a patch having roughness was selected by ten randomly selected persons. The sample at this time has L = 70, and a and b have a spacing of 5 from -75 to -75, respectively. Judgment method is to place a sample on 10 unprinted media and use a fluorescent light (color rendering AAA: FLR40SN-EDL).
/ M) and visually confirm at a distance of 30 cm.

There were three criteria: (1) there was roughness; (2) there was no roughness; and (3) no judgment was made.

FIG. 3 shows the results of the case where the above-mentioned ten persons judged each of the above patches a), b) and c) and added one point each. The failure rate is 3
This is the number of head replacement when printing 2,000 square meters. Here, it is assumed that a failure of the head itself and a contact between the head and the medium or a cleaning failure are included.

The color gamut is a color reproduction range when the color sample mark (manufactured by SCOTDIC: published by Kensaikan Co., Ltd.) is 100%.
= 20 to 90 at intervals of 10 and a and b at -75 to 75, respectively, at intervals of 5 samples.

As compared with Example 1, Comparative Example 1 did not change the color gamut, but it was found that the roughness was extremely poor. Further, when Examples 2 to 5 and Comparative Example 2 were compared, it was found that the color gamut did not change, but the roughness was significantly inferior.

That is, from this point, it was found that the use of the K2 ink was effective in eliminating the roughness. When comparing Example 6 with Comparative Example 3, the roughness and the color gamut did not change, but the number of mounted heads was large, and in addition to the head failure rate,
In terms of electrical for driving the head, mechanical for mounting the head, and system for supplying ink,
Greatly inferior.

When comparing Example 7 with Comparative Example 4, the roughness and color gamut are not changed, but the number of mounted heads is large, and the electrical, mechanical, and system are inferior. Example 5 and Comparative Example 4 are inferior in color gamut.

Examples 8 to 10 have different color gamut ranges, but have the same level of color gamut when viewed from the entire color sample mark.
In addition, since there is no unnecessary yellow and orange light-colored ink that does not contribute to roughness, it is advantageous in terms of electrical, mechanical, and system.

In Examples 12 to 16, the black portion was formed with Y ink, C ink and M ink except for the dark black ink, and was formed with K ink, Y ink, C ink and M ink. Black, which is slightly different from black in some places, is almost at the same level, the number of heads can be reduced, and it is advantageous in terms of electrical, mechanical, and system.

Also, as an embodiment not shown here, when expressing gradation using achromatic ink and chromatic ink, the number of achromatic inks having different densities is as follows.
It has been found that an effect effective in eliminating roughness can be obtained by performing the gradation expression of the chromatic color by area gradation in addition to the number of inks having different densities of any one of the chromatic colors.

As specific examples, K, K2, Y, Y2,
This corresponds to a case where a chromatic color is expressed by area gradation using M and C inks. In the case of this specific example, the ink concentration for K is larger than the number of M and C inks. In this case, although chromatic colors include yellow, cyan, and magenta as basic colors, it is preferable that chromatic colors include red, blue, and violet as special colors.

Considering the above results, in order to form a high-quality color image without roughness without causing image deterioration and cost increase due to bleeding, etc., it is necessary to use an achromatic ink and a chromatic ink. When performing gray scale expression, gray scale expression of achromatic color is performed by density gray scale, and gray scale expression of chromatic color is performed by area gray scale.

The above density gradation changes the number of dots to be printed per unit area and changes the density of the dots. The small area gradation changes the number of dots to be printed per unit area and changes the dot diameter.

When expressing gradation using achromatic ink and chromatic ink, the following condition 1 is satisfied for achromatic color, and the following condition 2 or When either condition 3 is satisfied, the gradation expression is performed by density gradation, and when neither condition is satisfied, the gradation expression is performed by area gradation.

Condition 1: achromatic color where L <40 Condition 2: chromatic color where L <55 Condition 3: Lab of the finally formed image and Lab of the ink itself forming the image A chromatic color where the difference δE is δE> 60 The above density gradation changes the number of dots to be printed per unit area and changes the dot density.

The above-mentioned area gradation changes the number of dots to be printed per unit area and changes the diameter of the dots. The number of inks having different achromatic color densities is set to be greater than the number of inks having different densities of any one of the chromatic colors, and the chromatic color gradation is expressed by area gradation.

The basic colors are yellow, cyan, and magenta as the chromatic colors. Red, blue, and violet are featured as the above or chromatic colors. Proved effective.

Next, the case where the ink jet recording of each of the above embodiments is used for printing will be described. Polyester decyne was used as "cloth" as a recording medium.
The yarn diameter and number of WARPS and WOOFS are as follows. WARPS: 75d 172STRINGS / 25.4mm WOOFS: 75D 108STRINGS / 25.4mm To prevent image bleeding, dilute the cationic activator laurylbenzylammonium chloride to 10g / L as a pre-treatment agent, immersion method, pad method For example, the applied amount is about 0.2% to 10%.

After drying, an image was formed with the ink of each of the above-described embodiments using a disperse dye. After the image formation, it was dried and subjected to a color development treatment for about 10 minutes in a high-temperature steamer at 173 ° C. Next, the excess pretreatment agent and non-adhered dye were removed by washing with water and warm water. By doing so, it was confirmed that a good image without roughness was obtained as compared with conventional printing.

[0055]

As described above, by using the recording apparatus and the recording method of the present invention, it is possible to form a high-quality color image with no dot granularity peculiar to ink jet, that is, without roughness. In addition, it has electrical, mechanical, and system advantages, without increasing costs,
High quality printing can be performed at low cost.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a configuration of an inkjet recording apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an ink used for inkjet recording according to the present invention.

FIG. 3 is an explanatory diagram showing a rough state due to ink jet recording of the present invention.

[Explanation of symbols]

 Reference Signs List 20 inkjet recording device 30 color conversion processing unit 40 error diffusion processing unit 50 printer data conversion unit 60 output unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C056 EA05 EA11 ED01 ED03 ED07 EE09 EE18 FB03 2C057 AF27 AF39 AF91 CA01 CA04 CA07

Claims (12)

[Claims] 1. An ink jet recording method for performing recording by attaching dots of ink droplets of a plurality of colors on a recording medium, wherein gradation is expressed using achromatic ink and chromatic ink. In this case, an achromatic color gradation expression is performed by a density gradation, and a chromatic color gradation expression is performed by an area gradation. 2. An ink jet recording method for performing recording by adhering dots of ink droplets of a plurality of colors on a recording medium, wherein gradation is expressed using achromatic ink and chromatic ink. In this case, the number of inks having different densities of achromatic colors is larger than the number of inks having different densities of any one of the chromatic colors, and the chromatic color gradation expression is performed by area gradation. Inkjet recording method. 3. An ink jet recording apparatus for performing recording by adhering dots of ink droplets of a plurality of colors on a recording medium, wherein gradation is expressed using achromatic ink and chromatic ink. In this case, an achromatic color gradation expression is performed by density gradation, and a chromatic color gradation expression is performed by area gradation. 4. The ink jet recording apparatus according to claim 3, wherein the density gradation changes the number of dots to be printed per unit area and changes the density of the dots. 5. The ink-jet recording according to claim 3, wherein the area gradation changes the number of dots to be recorded per unit area and changes the diameter of the dots. apparatus. 6. An ink jet recording apparatus for performing recording by attaching dots of ink droplets of a plurality of colors on a recording medium, wherein gradation is expressed using achromatic ink and chromatic ink. At this time, for achromatic color, the following condition 1 is satisfied,
For chromatic colors, tone expression that satisfies either Condition 2 or Condition 3 below is performed using density tone.
An ink jet recording apparatus characterized in that when none of the conditions is satisfied, the gradation expression is performed by area gradation. The Lab value shown here is based on CIE1976 (L
ab) shows the perceived chromaticity index defined in space. Condition 1: achromatic color where L <40 Condition 2: chromatic color where L <55 Condition 3: The difference δE between the Lab of the finally formed image and the Lab of the ink itself forming the image is Chromatic color where δE> 60 7. The ink jet recording apparatus according to claim 6, wherein the density gradation changes the number of dots to be printed per unit area and changes the dot density. 8. The ink-jet recording according to claim 6, wherein the area gradation changes the number of dots to be recorded per unit area and changes the diameter of the dots. apparatus. 9. An ink jet recording apparatus for performing recording by attaching dots of ink droplets of a plurality of colors on a recording medium, wherein gradation is expressed using achromatic ink and chromatic ink. In this case, the number of inks having different densities of achromatic colors is larger than the number of inks having different densities of any one of the chromatic colors, and the chromatic color gradation expression is performed by area gradation. Inkjet recording device. 10. An ink jet recording apparatus according to claim 9, wherein said chromatic colors include yellow, cyan and magenta as basic colors. 11. An ink jet recording apparatus according to claim 9, wherein said chromatic colors include red, blue and violet as special colors. 12. The ink jet recording apparatus according to claim 3, wherein said ink jet recording apparatus is for textile printing.