JPH0383654A - Color printer - Google Patents

Abstract

PURPOSE:To make possible the exact reproduction of colors including white using recording paper with different background colors by providing a constitution in which white ink or toner can stick to a recording pixel area on recording paper before ink or toner is allowed to stick. CONSTITUTION:Chromatic decomposition data for each pixel entered from an interface part is stored in a line buffer for input data, then data for application of white ink to a recording pixel area for given input data is sent to a recording signal source 46 using CPU and white ink is applied to the recording pixel area. The white ink used should be one with the reflection factor, of the recording pixel area to which the white ink is applied, that is not actually influenced by the chromatic difference of recording paper 9. Cyan, magneta and yellow inks are not used simultaneously due to the different positions of ink nozzles. First data for cyan is sent to a recording signal source 4, then the cyan ink is applied to the recording paper 9 and other chromatic decomposition data is sent if an appropriate ink nozzle is positioned on a pixel to which the cyan ink is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color printer, and particularly to a color printer that can accurately reproduce colors without being affected by the base color of recording paper.

[Conventional technology]

Conventionally, a document is divided into predetermined pixels, and cyan, magenta, and yellow inks are applied to the recording paper for each pixel based on the color separation data obtained for each pixel. Color printers have been developed that form recording colors of red, green, blue, and black, and create color images by combining them. In such color printers, the color separation data for each pixel is subjected to color correction processing, etc., and then cyan, cyan,
Magenta and yellow inks were applied to the recording paper. As a color correction process, for example, as shown in equation (1) below, color separation data of a color image is multiplied by a color correction coefficient to obtain adhesion amount control data for each ink.

R, G, B: Color image color separation data C, M, Y ink adhesion amount control data a, (i, j, = l to 3): Color correction coefficient [solved by the invention] However, in the color printers mentioned above, when reproducing white, a method was used in which no cyan, magenta, or yellow ink was applied; The problem is that it is impossible to reproduce white color with recording paper other than white.

Furthermore, with non-white recording paper, even if cyan, magenta, and yellow inks are applied to the recording paper after color correction processing is applied to the color separation data, the accuracy will be affected by the color of the recording paper. There was a problem that it was not possible to reproduce accurate colors.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a color printer that can accurately reproduce colors including white even when using various recording papers with different base colors. .

[Means to solve the problem]

To achieve this purpose, the color printer of the present invention has the following features:
In a color printer that creates a color image by depositing at least three colors of ink or toner, cyan, magenta, and yellow, on a recording paper according to given color separation data for each pixel, before depositing the ink or toner, It is configured so that white ink or toner can be applied to the recording pixel area on the recording paper.

[Effect]

The color printer of the present invention having the above configuration first attaches white ink or toner to the recording pixel area on the recording paper when color separation data for each pixel is given, and then applies the color separation data for each of the given pixels. Recording pixels are formed by depositing ink or toner of at least three colors, cyan, magenta, and yellow, on recording paper according to color separation data for each pixel. Therefore, various colors including white can be accurately reproduced based on the color separation data provided for each pixel without being affected by the color of the recording paper.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic perspective view showing an embodiment of a color printer of the present invention. In FIG. 1, the color printer of the present invention has a screw shaft 3 which is slidably disposed on a sliding shaft 1 and is rotationally driven by a head carry pulse motor 2. A paper feed roller 11 driven by a paper feed pulse motor 10 for feeding the recording paper 9 in a direction perpendicular to the moving direction of the head 4 and the ink ejecting head 4.
It is equipped with The ink ejecting head 4 has a white ink nozzle 5, a cyan ink nozzle 6, a magenta ink nozzle 7, and a yellow ink nozzle 8, which are arranged in a straight line parallel to the axial direction of the sliding shaft 1, with their axes oriented parallel to each other in the same direction. It is located in

Further, each of these ink nozzles has an ink supply tube 12, 1 for supplying the corresponding ink.
3.14.15 are connected.

FIG. 2 is a schematic diagram of the ink nozzle shown in FIG. 1. Since the configurations of the ink nozzles 5, 6, and 7° 8 are the same, in Fig. 2, the cyan ink nozzle 6
will be explained as an example. In FIG. 2, the cyan ink nozzle 6 includes a piezoelectric element 24 for vibrating the pressurized cyan ink 23 sent from the cyan ink tank 21 by the cyan ink pressurizing device 22 through the cyan ink supply tube 13. a cyan nozzle 25 for extruding pressurized cyan ink 23 as a cyan ink column 26; a charging electrode 28 for charging cyan ink particles 27 separated from the cyan ink column 26; and a deflector for deflecting the cyan ink particles 27. It includes an electrode 29 and a cyan ink groove 30. The piezoelectric element 24 is connected to a high frequency power source 31, and this high frequency power source 31 is connected to a charging electrode 28 via a recording signal source 46, which will be described later. In addition, the deflection electrode 2
9 is connected to a DC high voltage source 32.

FIG. 3 is a block diagram for explaining means for controlling the amount of ink adhesion. In FIG. 3, the control means includes an interface unit 41 for inputting color separation data for each pixel, an input data line buffer 42 for storing color separation data for each pixel taken in by this interface unit 41, and a RAM 43. A CPU 45 performs signal processing according to the contents of the ROM 44, and a recording signal source 46 controls ink charging according to input color separation data for each pixel.

Next, the operation of the color printer of the present invention shown in FIGS. 1 to 3 will be explained. First, each color separation data for each pixel input from the interface section 41 is stored in the input data line buffer 42. and,
Data for applying white ink to the recording pixel area of the given input data is sent by the CPU 45 to the recording signal source 46, and white ink is applied to the recording pixel area. The white ink used is such that the reflectance of the recording pixel area coated with the white ink is substantially unaffected by the difference in color of the recording paper. Here, the cyan, magenta, and yellow inks are not printed at the same time because the ink nozzles are arranged at predetermined intervals as shown in FIG. 1, and the positions of the ink nozzles are different. First, cyan data is sent to the recording signal source 46, and cyan ink is applied to the recording paper 9. Further, color separation data for other colors is sent to the recording signal source 46 when the corresponding ink nozzle is located on a pixel to which cyan ink was applied first.

Here, the application operation will be explained in more detail using cyan ink as an example. Note that all other color inks are applied to the recording paper in the same manner as the cyan ink. Pressurized cyan ink 23 is sent from a cyan ink tank 21 to a nozzle 25 by a cyan ink pressurizing device 22 . This nozzle 2
5 is vibrated by a piezoelectric element 24 excited by a high frequency voltage supplied from a high frequency power source 31. For this reason, the ink column 26 passing through the nozzle 25 also vibrates, causing the nozzle 2
The ink column 26 extruded from the ink droplets 26 continuously separates into ink particles 27 that are uniform in size and flight speed.

When applying the ink particles 27 separated and formed in this way onto the recording paper 9, a recording signal voltage is applied to the charging electrode 28 based on the cyan data sent to the recording signal source 46, and the ink particles 27 are applied to the recording paper 9. Particles 27 are charged recording particles 3
It becomes 3. When the recording particles 33 pass through the electrostatic field formed between the deflection electrodes 29, they receive a deflection force depending on the amount of charge and adhere to a predetermined position on the recording paper 9. On the other hand, when the ink particles 27 are not applied onto the recording paper 9, no recording signal voltage is applied to the charging electrode 28 based on the cyan data sent to the recording signal source 46, and the ink particles 27 are not charged. This results in unnecessary particles 34. Even when these unnecessary particles 34 pass through the electrostatic field formed between the deflection electrodes 29, they do not receive any deflection force, continue straight, are stopped from flying by the cyan groove 32, and adhere to the recording paper 9. There isn't. The unnecessary particles 34 whose flight is prevented by the cyan groove 32 are collected as unnecessary ink in a cyan ink tank and reused.

By repeating the above operation with white ink, cyan ink, magenta ink, and yellow ink while moving the ink jetting head along the sliding shaft 1 by the head carry pulse motor 2, the recording paper 9 is printed on the recording paper 9 for each pixel. A color image is recorded, and the process ends when all of the given color separation data has been recorded.

In the above-mentioned embodiment, white ink was uniformly applied to the recording pixel area in advance regardless of the base color of the recording paper, but in the color printer of the present invention, it is possible to select whether or not to apply white ink in advance. Good too. In this case, for example, a colorimeter for measuring the color of the recording paper is attached to the ink jetting head 4.
The color of the recording paper is set in advance and stored in the RAM 43 to influence the color of the recording paper on the final recorded image, and the color of the recording paper is adjusted to the final recorded image based on the color measurement results of the colorimeter. The CPU 45 may determine whether the color of the recording paper affects the final recorded image, and apply white ink to the recording pixel area in advance only when it is determined that the color of the recording paper affects the final recorded image.

By doing so, when the color of the recording paper is sufficiently close to white, application of white ink can be stopped, and the amount of white ink used and the recording time can be reduced.

Note that the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit thereof. For example, instead of just one set of four ink nozzles of white, cyan, magenta, and yellow, a plurality of similar ink nozzle combinations may be provided.

〔Effect of the invention〕

As is clear from the above detailed description, according to the present invention, since the recording is performed using white ink in advance on the recording pixel area so as to cancel out the color of the recording paper, the color of the recording paper is not affected. Various colors including white can be accurately reproduced based on the color separation data for each pixel given without any limitations.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing an embodiment of the color printer of the present invention, FIG. 2 is a schematic configuration diagram of the ink nozzle shown in FIG. 1, and FIG. 3 shows means for controlling the amount of ink adhesion. FIG. 2 is a block diagram for explanation. 4... Ink ejection head, 5... White ink nozzle, 6... Cyan ink nozzle, 7... Magenta ink nozzle, 8... Yellow ink nozzle, 9... Recording paper, 12. 13, 14.15... Ink supply tube, 21... Cyan ink tank, 24... Piezoelectric element, 25... Cyan nozzle, 26... Cyan ink column, 27... Cyan ink particle, 28... Charge electrode, 29... Deflection electrode, 30... Cyan ink groove, 41... Interface section, 42... Line buffer for input data, 43... RAM, 44... R
OM. 45...CPU, 46...Recording signal source.

Claims (1)

[Scope of Claims] 1. A color printer that creates a color image by depositing at least three colors of ink or toner, cyan, magenta, and yellow, on a recording sheet according to color separation data for each pixel, wherein the ink Alternatively, a color printer is characterized in that white ink or toner can be applied to recording pixel areas on recording paper in advance before toner is applied. 2. The white ink or toner is white ink or toner in which the reflectance of the recording pixel area to which the white ink or toner is attached is not affected by the color of the recording paper. Color printer as described. 3. The image forming apparatus according to claim 1 or 2, further comprising a selection means for selecting whether or not white ink or toner is to be attached to the recording pixel area on the recording paper before the ink or toner is attached. color printer. 4. The selection means measures the color of the recording paper and determines whether the color of the recording paper affects the final recorded image according to a preset criterion, and the color of the recording paper determines whether the color of the recording paper affects the final recorded image. 2. The color printer according to claim 1, wherein the color printer selects to apply white ink or toner to all recording pixel areas on the recording paper in advance only when it is determined that the image will be affected.