JPS59218862A - Color ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To enable recording with wide gradation, by providing a head for injecting a colorless transparent ink to the outside of heads for injecting color inks of cyan, yellow and magenta. CONSTITUTION:An ink jet head 2a for injecting colorless transparent ink droplets is provided along with ink jet heads 2, 2, 2 for respectively injecting ink droplets having colors of cyan (C) yellow (Y) and magenta (M) so as to be capable of injecting the same in superposed relation to the ink droplets from said heads 2, 2, 2. By this mechanism, the color tone of one dot can be changed by the diluting effect of the colorless transparent ink and gradation can be simply obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color inkjet recording device, and more particularly to a color inkjet recording device suitable for halftone recording.

[In addition, Figure 1 is a configuration diagram showing an example of a conventional on-Φ-demand type color inkjet recording device.
indicates yellow, C indicates cyan, and M indicates magenta ink ejection system, and as is well known, these three color ink droplets of yellow (Y), cyan (C), and magenta (M) are ejected onto the recording paper 3.
Overlap with J2 to get the desired color! [I'm here. Then,
In color inkjet recording devices, gradation is a problem in order to perform halftone recording, but in order to obtain this gradation, conventionally, a matrix or the like has been used to change the dot density to obtain gradation. In the on-demand head, a method has been proposed in which gradation is achieved by changing the dot diameter by changing the amplitude of the driving voltage. In the case of the head, it is difficult to express halftones in the bright areas of the three images, and in the latter part, the amplitude of the driving voltage cannot be made very wide, resulting in problems such as a small range of change in dot diameter.

Purpose The present invention was made in view of the actual situation as described in -, and in particular, the present invention was made for the purpose of enabling a wide range of gradations to be performed in a color inkjet recording device in which the dot diameter cannot be made very small. It is something that

1-1 The configuration of the present invention will be described below based on one embodiment.

FIG. 2 is a block diagram showing the main parts of an embodiment of the color inkjet recording apparatus according to the invention.
The conventional color inkjet recording device shown in the figure is provided with an ink tank la for colorless and transparent ink, and an inkjet head 2a, and the colorless and transparent ink droplets ejected from the inkjet head 2a are ejected from other inkjet heads. Colored ink and recording paper 3. ), the color tone can be changed by matching the hairs. However, if the single-color ink particles and the colorless transparent ink particles have a diameter i, the color tone will not change even if the particles are overlapped on the recording paper, and color bleeding may occur. As shown in the figure, the nozzle hole diameter of the colorless and transparent ink dedicated head 2a is made larger than the 7 nozzle hole diameters of the other heads to create colorless and transparent ink droplets that are larger than other color ink droplets. By overlapping colored ink droplets, the color tone can be changed. Although the dots I produced in this manner are larger than other dots, there is no problem with print quality if the pitch number of the drive pulse is changed only when the droplets are returned. In addition, in on-demand type inkjet heads, the size of ink droplets can be changed to some extent by changing the drive pulse voltage, and the size of colored ink droplets is within a range smaller than the size of colorless transparent ink droplets. By changing the diameter of the 4L ink droplets and overlapping the recording sheets, it is possible to widen the range of color tone and dot diameter gradation. Furthermore, by adding a lubricant to the colorless and transparent ink, the dye of the colored ink can be spread quickly and uniformly.

As is clear from the explanation in Kita-1, according to the present invention, the color tone of one dot can be changed by the thinning effect of colorless transparent ink, so that it is possible to change the color tone of one dot, which is different from the conventional density gradation or gradation based on dot diameter. You can obtain gradation more easily than with . Also,
By combining the conventional density gradation or gradation based on dot diameter with the gradation according to the present invention, there are advantages such as the ability to widen the range of intermediate expression.

[Brief explanation of drawings]

FIG. 1 is a block diagram of main parts showing an example of a conventional color inkjet recording apparatus, and FIG. 2 is a block diagram of main parts showing an example of a color inkjet printing apparatus according to the present invention. 1.1a... Ink tank, 2,2a... Infusiera j/Hera 1-13... Recording paper. Special t1-Applicant Ricoh Co., Ltd. Figure 1 6 Figure 2 333-

Claims (3)

[Claims] (1), cyan (C), yellow (Y), magenta (M
) An inkjet that ejects colorless and transparent ink droplets in a recording device that has an inkjet head dedicated to each color and performs color printing by overlapping ink droplets of each color ejected from each head on recording paper. 1. A color inkjet recording apparatus comprising a head, the colorless transparent ink droplets and the color ink droplets being superimposed on the recording paper. (2) The color inkjet recording apparatus according to claim (1), wherein the colorless transparent ink contains a lubricant. (3) The color inkjet recording vcM according to claim (1) or (2), characterized in that the particle size of the colorless transparent ink droplet is larger than the particle size of the color ink droplet. .