JP3375994B2 - Inkjet recording method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording method.

[0002]

2. Description of the Related Art The ink jet recording system has advantages such as low noise, high speed recording and color recording.

In particular, the applicant of the present invention has proposed that the Japanese Patent Publication No. 61-5991.
According to the method (so-called bubble jet recording method) disclosed in No. 1, 59912, 59913, 59914, which uses an electrothermal converter as an ejection energy supply means and causes thermal energy to act on a recording liquid to eject droplets (so-called bubble jet recording method). Since high density multi-orifice can be easily realized, high resolution and high quality images can be recorded at high speed.

However, in the ink jet printer using the water-based ink, there is a problem that it takes time until the ink is fixed on the recording paper. Also,
There is a strong demand for plain paper, as well as inkjet-coated coated paper, as recording paper. In this case, the fixing time becomes longer.

Various investigations have been made to date in order to increase the fixing speed of ink. In particular, the present applicant has proposed an ink having good fixability corresponding to plain paper, which is capable of quickly fixing by increasing wettability with respect to plain paper.

However, since such an ink penetrates well into the paper, the coloring material (dye / pigment) also penetrates into the paper, and the image density generally tends to be low. This problem is particularly noticeable in black characters / images.

Therefore, from the viewpoint of print quality, it is not preferable to make the wettability of the black ink too high, but in that case, the fixability of the black ink cannot be made sufficiently high, so that a high-density black image continues. There remains a problem that an image is disturbed due to a paper transport roller or the like coming into contact with a recorded portion, and a finger is soiled when the recording paper immediately after recording is touched.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to prevent deterioration of fixing property of a high density black image recording portion while maintaining the image quality of a black image as much as possible.

[0009]

The above object can be achieved by the present invention described below.

That is, the ink jet recording according to the present invention
The method includes a black ink having a first permeability to the recording medium and a second ink having a higher permeability to the recording medium.
In the ink jet recording method of an image including a black image, which has a step of applying a color ink having penetrating property by an ink jet method, a region where the black image is recorded on the recording medium, which is determined by the data of the black image. When the amount of the black ink to be applied per unit area of the black ink exceeds the threshold value for lowering the fixing property of the black ink on the recording medium, the color ink and the black ink are applied to the area to remove the black ink. The image is formed and the amount of black ink is
If it is less than or equal to the threshold value, the black ink alone
An inkjet recording method is characterized in that an image is formed . Further, the method for improving an ink jet recorded image according to the present invention is a method for improving an ink jet recorded image including a black image on a recording medium, wherein the black image on the recording medium is determined by the data of the black image. When the amount of the black ink to be applied per unit area of the recording area exceeds the threshold value for lowering the fixing property of the black ink on the recording medium, the black ink and the black ink are applied to the area.
Control so that a color ink having a higher permeability than that of the black ink is applied.
It is a method for improving an inkjet-recorded image, which comprises a step of controlling so that only ink is applied.

[0011]

The details of the present invention will be described with reference to the following examples.

Example 1 A black ink was prepared by the procedure shown below (parts represent parts by weight unless otherwise specified). a) Preparation of pigment dispersion styrene-acrylic acid-butyl acrylate copolymer 2 parts (acid value 116, weight average molecular weight 3700) monoethanolamine 1 part diethylene glycol 5 parts ion-exchanged water 73 parts The above components are mixed and water is added. Heat to 70 ° C in the bath,
Dissolve the resin component. After adding 14 parts of carbon black (manufactured by Mitsubishi Kasei Co., Ltd.) and 5 parts of isopropyl alcohol and premixing for 30 minutes, dispersion treatment was carried out under the following conditions.

Disperser Sand grinder Grinding media Zirconium beads (1
mm diameter) Grinding media filling rate 50% by volume Grinding time 3 hours Further centrifugal separation treatment (12000 RPM, 20 minutes)
Then, a pigment dispersion liquid was obtained. b) Preparation of black ink Dispersion liquid of the above a) 30 parts Diethylene glycol 15 parts Isopropyl alcohol 5 parts Ion-exchanged water 50 parts Mix the above components, add monoethanolamine and adjust the pH.
Was adjusted between 8 and 10 to obtain a black ink.

The color ink was prepared by the following formulation. a) Yellow ink Dye C.I. I. Direct Yellow 86 2.5 parts Thiodiglycol 7.5 parts Glycerin 7.5 parts Urea 7.5 parts Nonionic surfactant acetylenol (Kawaken Fine Chemicals Co., Ltd.) 5 parts Ion-exchanged water balance b) Magenta ink dye C.I. I. Acid Red 35 3.0 parts Thiodiglycol 7.5 parts Glycerin 7.5 parts Urea 7.5 parts Nonionic surfactant acetylenol (Kawaken Fine Chemicals Co., Ltd.) 5 parts Ion-exchanged water balance c) Cyan ink dye C.I. I. Direct Blue 199 3.0 parts Thiodiglycol 7.5 parts Glycerin 7.5 parts Urea 7.5 parts Nonionic surfactant acetylenol (Kawaken Fine Chemicals Co., Ltd.) 5 parts Ion-exchanged water The rest color ink is mixed and sufficient After stirring, pore size 0.2
A 2 μm fluoropore filter (manufactured by Sumitomo Electric Industries, Ltd.) was used after pressure filtration.

FIG. 1 shows an example of the recording apparatus used in the present invention. The recording paper 9 is recorded by the recording head 1 and then ejected by the paper ejection system 10.

Recording heads 1y, 1m, 1c, 1BK
Has 64 nozzles with a density of 360 nozzles per inch, and can eject ink at a frequency of 6 kHz based on print data.

An example of the recording method of the present invention will be described below.

In the recording method of this embodiment, color image data other than black is recorded as it is, and black image data is recorded according to the following cases. (1) The number of pixels for which black recording is to be performed is 100% with one unit of 4 vertical nozzles x 4 horizontal dots (that is, 16 pixels).
In the case of 16 pixels (that is, 16 pixels), a black image is recorded using the black ink and the yellow, magenta, and cyan inks in the pattern shown in FIG. (2) Vertical 4 nozzles x horizontal 4 dots (that is, 16 pixels) is one unit, and the number of pixels for black recording is 10
When it is less than 0% (that is, 15 pixels or less): Black ink is recorded according to the image data.

As a result of the recording, almost no deterioration in image quality was observed, and no image distortion occurred even in the portion where the high-density black image portion was in contact with the paper discharge system.

Example 2 Using the recording apparatus and ink used in Example 1, black image data was recorded according to the following cases. (1) The number of pixels for which black recording is to be performed is 100% with one unit of 4 vertical nozzles x 4 horizontal dots (that is, 16 pixels).
(Ie 16 pixels): 50 randomly selected
50% of the pixels are left with black ink
A black image is recorded on the% pixels by using yellow, magenta, and cyan inks. (2) Vertical 4 nozzles x horizontal 4 dots (that is, 16 pixels) is one unit, and the number of pixels for black recording is 10
When it is less than 0% (that is, 15 pixels or less): Black ink is recorded according to the image data.

As a result of recording, almost no deterioration in image quality was observed, and no image distortion occurred even in the portion where the high-density black image portion was in contact with the paper discharge system.

Example 3 Using the recording apparatus and ink used in Example 1, black image data was recorded according to the following cases. (1) The number of pixels for which black recording is to be performed is 100% with one unit of 4 vertical nozzles x 4 horizontal dots (that is, 16 pixels).
In the case of 16 pixels (that is, 16 pixels): black ink is applied to all pixels, and yellow, magenta, and cyan inks are applied to 4 pixels that do not overlap each other.

In this case, the total amount of ink ejected on the recording paper is larger than that when only black ink is used, but according to the study by the present inventors, the fixing speed of a black image is improved. . This is probably because the effect of improving the wettability of the recording paper by the nonionic surfactant contained in the color ink extends to the black ink. (2) Vertical 4 nozzles x horizontal 4 dots (that is, 16 pixels) is one unit, and the number of pixels for black recording is 10
When it is less than 0% (that is, 15 pixels or less): Black ink is recorded according to the image data.

As a result of the recording, almost no deterioration of the image quality was observed, and the image was not disturbed even in the portion where the high-density black image portion was in contact with the paper discharge system.

Example 4 Using the recording apparatus and ink used in Example 1, black image data was recorded according to the following cases. (1) The number of pixels for which black recording is to be performed is 90 with one unit of 64 nozzles vertically × 4 dots horizontally (that is, 256 pixels).
% Or more: The black ink is recorded on the corresponding pixel, and the yellow, magenta, and cyan inks are recorded on each 64 pixels of the corresponding pixel so as not to overlap each other. (2) When 64 nozzles in the vertical direction and 4 dots in the horizontal direction (that is, 256 pixels) are set as one unit, and the number of pixels for which black recording is performed is less than 90%: Recording by black ink is performed according to image data.

As a result of the recording, almost no deterioration in image quality was observed, and no image distortion occurred even in the portion where the high-density black image portion was in contact with the paper discharge system.

[0027]

As described above, according to the present invention,
While maintaining the image quality of the black image as much as possible, it is possible to prevent the fixing property of the high density black image recording portion from being deteriorated.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an example of a recording apparatus used in the present invention.

FIG. 2 is a diagram illustrating an example of a recording pattern used in the present invention. (A) shows a recording pattern of black ink. (B) shows a recording pattern of yellow ink. (C) shows a recording pattern of magenta ink. (D) shows a recording pattern of cyan ink.

[Explanation of symbols]

1 recording head 9 Recording paper 10 Paper ejection system

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B41J 2/01 B41J 2/05 B41J 2/205 B41J 2/21 C09D 11/00

Claims (7)

(57) [Claims] 1. A black ink having a first permeability and a color ink having a second permeability higher than the first permeability are applied to the recording medium by an inkjet method. In the inkjet recording method of an image including a black image, which has a step, the amount of black ink to be applied per unit area of the region on the recording medium where the black image is recorded is determined by the data of the black image, Applying the black ink to the recording medium
When the adhesion lowering threshold is exceeded, the color ink and the black ink are applied to the region to form the black image,
If the amount of black ink is less than the threshold value, the black ink
An ink jet recording method , wherein the black image is formed only by a black mark . 2. The ink jet recording method according to claim 1 , wherein both the black ink and the color ink contain a nonionic surfactant, and the content of the nonionic surfactant is the smallest in the black ink. 3. The at least one nonionic surfactant is selected from ethylene oxide adducts of higher alcohols, ethylene oxide adducts of alkylphenols, ethylene oxide adducts of polyhydric alcohols, and ethylene oxide adducts of acetylene glycol. The inkjet recording method according to claim 2 , wherein 4. The black ink is a pigment ink.
Item 2. The inkjet recording method according to Item 1. 5. A unit surface of an area in which the black image is recorded
The amount of black ink to be applied per product is the black ink.
If the threshold value of the fixability of the unit to the recording medium is exceeded, the unit
When the black ink is applied to 90% of the pixels in the area
The inkjet recording method according to claim 1. 6. A unit surface of an area in which the black image is recorded
The amount of black ink to be applied per product is the black ink.
If the threshold value of the fixability of the unit to the recording medium is exceeded, the unit
When the black ink is applied to 100% of the pixels within the area
The inkjet recording method according to claim 1, wherein 7. A method for improving an ink jet recorded image including a black image on a recording medium, wherein a unit area of a region of the recording medium, in which the black image is recorded, is determined by data of the black image. When the amount of the black ink to be applied exceeds the threshold value for lowering the fixing property of the black ink on the recording medium, the black ink and the black ink are applied to the area.
Control so that a color ink having a higher permeability than that of the black ink is applied.
A method for improving an inkjet-recorded image, comprising the step of controlling so that only ink is applied .