JPH0384567A - Color printer - Google Patents

Abstract

PURPOSE:To accurately reproduce the color of each picture element with supplied color separation data by determining control data on the resticking quantity of ink or toner according to the result of measurement of recording colors of recording picture elements and then sticking the ink or toner on the recording picture element again according to the control data. CONSTITUTION:A color image is formed by sticking ink or toner particles of at least cyan, magenta and yellow on a recording form according to the supplied color separation data in picture element units and the recording colors of the recorded picture elements are measured. Then a CPU 55 compares the recording colors with color separation data stored in a line buffer 52 for input data by picture elements, stores the result of color difference calculation in a line buffer 58 for color differences, and apply the ink again to picture elements whose color differences are larger than a specific value according to the color differences stored in the color difference line buffer 58. Consequently, the colors of respective picture elements can accurately be reproduced with the supplied color separation data by the picture elements.

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 the color of given color separation data for each pixel.

[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 each recording color by combination to create a color image.

In such color printers, the color separation data for each pixel is subjected to color correction processing, and then cyan, magenta, and yellow inks are applied to the recording paper. As a color correction process, for example, the following formula (1
), the color image color separation data is multiplied by the color correction coefficient to determine the adhesion of each ink. R, G, B: Color image color separation data C, M, Y, Nidian, Magenta,
Adhesion amount control data for each ink of yellow・a,, (i, j=l~3) two-color correction coefficient" [Problem to be solved by the invention] However, color correction coefficients such as errors in color correction coefficients at the time of initial setting Due to inaccurate correction processing, fluctuations over time after initial settings, and deterioration of color reproducibility due to variations in the color of the base of the recording paper, etc.
There is a problem in that color separation data for each pixel cannot be accurately reproduced.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a color printer that can accurately reproduce colors for given color separation data for each pixel.

[Means to solve the problem]

The color printer of the present invention is a distant relative of this purpose.
In a color printer that creates a color image by depositing at least three colors of ink or toner, cyan, magenta, and yellow, on recording paper according to color separation data for each pixel, the ink or toner is deposited and recorded. a colorimeter for measuring the recorded color of a pixel; a control data creation means for determining control data for the amount of redeposition of ink or toner from the colorimetric results of the colorimeter; and a pixel recorded in accordance with the control data. and an adhesion means for re-adhering the ink or toner to the ink or toner.

[Effect]

The color printer of the present invention having the above configuration forms recording pixels by depositing ink or toner of at least three colors, cyan, magenta, and yellow, on recording paper according to the color separation data given for each pixel, and performs measurement. The control data creation means determines control data for the amount of redeposition of ink or toner based on the result of the color measurement of the recorded color of this recording pixel by the color means, and based on this control data, the adhesion means applies ink or toner to the recording pixel. Attach it again. For this reason, the color separation data for each pixel can be accurately calculated for each pixel without being affected by inaccuracies in color correction processing, fluctuations over time, changes in the color of the base of the recording paper, etc. Can reproduce colors.

〔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 an ink deposit that is slidably disposed on a sliding shaft 1 and is moved along the sliding shaft 1 by a screw shaft 3 that is rotationally driven by a head carry pulse motor 2. An ink jetting head 4 as a means, a colorimeter head 5 as a colorimeter means which is connected to the ink jetting head 4 and moves at the same time, and an ink jetting head 4.
The paper feed roller 12 is driven by a paper feed pulse motor 11 for feeding the recording paper 10 in a direction perpendicular to the direction of movement of the recording paper 10 .

The ink ejecting head 4 has a white ink nozzle 6, a cyan ink nozzle 7, a magenta ink nozzle 8, and a yellow ink nozzle 9, which are arranged on a straight line parallel to the axial direction of the sliding shaft 1, with their axial directions parallel to each other. It is located in

Each of these ink nozzles also has an ink supply tube 14, 15 for supplying the corresponding ink.
．． 16°17 are connected. Further, a colorimeter nozzle 13 is disposed in the colorimeter head 5, and this colorimeter nozzle 13 is located on the same line as the direction in which each ink nozzle 6.7, 8.9 is arranged.

FIG. 2 is a schematic diagram of the ink nozzle shown in FIG. 1. Since the ink nozzles 6, 7, 8, and 9 have the same configuration, in Fig. 2, the cyan ink nozzle 7
will be explained as an example. In FIG. 2, the cyan ink nozzle 7 includes a piezoelectric element 24 for vibrating the pressurized cyan ink 23 that is sent from the cyan ink tank 21 via the cyan ink supply tube 15 by the cyan ink pressurizing device 22. 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 charging electrode 28 for deflecting and stirring the cyan ink particles 27. A deflection electrode 29 and a cyan ink groove 30 are provided. 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 56, 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 schematic diagram of the colorimeter head 5 and colorimeter nozzle 13. In FIG. 3, the colorimeter head 5
The colorimeter nozzle 13 includes a fiber 4 for sample illumination that guides the light emitted from the illumination generator 41 to the tip of the colorimeter nozzle 13 and irradiates it onto the recording paper 10 after application of ink.
2, a sample measurement fiber 43 for guiding the light reflected by the recording paper 10 out of the light irradiated from the sample illumination fiber 42 to a photoelectric conversion section to be described later, and a sample measurement fiber 43 for transmitting the light reflected by the recording paper 10 through the sample measurement fiber 43. A red filter 44, a green filter 45, and a blue filter 46 for color-separating the received light, and a red photoelectric conversion unit 47 that converts the light transmitted through each of these filters into electrical signals, respectively.
Green photoelectric conversion section 48 and blue photoelectric conversion section 4
9. The electrical signals converted by each photoelectric conversion section are then transferred to an analog/digital conversion section 57, which will be described later.
After being converted into a digital signal, the CPU 55 compares it with the color separation data for each pixel stored in the input data line buffer, and the result of calculating the color difference is stored in the color difference line buffer 58.

FIG. 4 is a block diagram for explaining a control means for determining control data for the amount of ink adhesion.

In FIG. 4, the control means includes an interface unit 51 for inputting color separation data for each pixel, an input data line buffer 52 for storing color separation data for each pixel taken in by this interface unit 51, and an RA.
a CPU 55 that performs signal processing according to the contents of the M"53 and the ROM 54; a recording signal source 56 that controls the charging of ink according to input color separation data for each pixel;
In the PU 55, the input data line buffer 52 and the color separation data for each separated color obtained from the analog/digital converter 57 are compared, and a color difference line buffer 58 is used to store the results calculated based on the comparison. It is equipped with

Next, the operation of the color printer of the present invention shown in FIGS. 1 to 4 will be explained. First, among the color separation data for each pixel inputted from the interface section 51, the other data excluding the cyan data are stored in the input data line buffer 52. Then, the cyan data is sent as is to the recording signal source 56, and the recording paper 10
cyan ink is applied to. Further, color separation data for other colors is sent to the recording signal source 56 when the corresponding ink nozzle is located on a pixel to which cyan ink was applied first. In this way, the color separation data is sequentially transmitted to the recording signal source 56.
This is because the ink nozzles are arranged at predetermined intervals as shown in FIG. 1, and all the ink nozzles are not located on the same pixel at the same time.

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 10, a recording signal voltage is applied to the charging electrode 28 based on the cyan data sent to the recording signal source 56, and the ink particles 27 are applied to the recording paper 10. The particles 27 become charged recording particles 33. 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 10. On the other hand, when the ink particles 27 are not applied onto the recording paper 10, no recording signal voltage is applied to the charging electrode 28 based on the cyan data sent to the recording signal source 56, 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 10. 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.

One pixel is recorded by repeating the above operation for magenta ink and yellow ink while moving the ink ejecting head along the sliding shaft 1 using the head carry pulse motor 2. After the yellow ink is applied, the colorimeter nozzle 13 is positioned over the recorded pixel, and the color of the pixel is measured. That is, first, the light emitted by the illumination generator 41 passes through the sample illumination fiber 43 and is irradiated onto the recorded pixels on the recording paper 10 . The light reflected by this pixel passes through a sample measurement fiber 43 and passes through a red filter 4.
4. The light transmitted to the green filter 45 and the blue filter 46, transmitted through each filter, and separated into colors is converted into an electric signal by the corresponding red photoelectric conversion section 47, green photoelectric conversion section 48, and blue photoelectric conversion section 49, respectively. is converted to The electrical signals converted by each photoelectric conversion unit are converted into digital signals by an analog/digital conversion unit 57, and then compared with color separation data for each pixel stored in the input data line buffer 52 in the CPU 55. The result of calculating the color difference is stored in the color difference line buffer 58.

In this way, while storing the input color separation data and the color difference between the recorded pixels in the color difference line buffer 58, the above-mentioned operation is repeated for each pixel in the order of cyan → magenta → yellow, and one line is printed on the recording paper. The pixels are recorded. After recording one row of pixels, the CPU 55 checks whether the color difference value stored in the color difference line buffer 58 is greater than or equal to a predetermined value. It is checked whether the reproduction of the separated data is insufficient, and for pixels whose color difference values are greater than or equal to a predetermined value, ink is applied again based on the color difference stored in the color difference line buffer 58. At this time, if each ink is applied less than the color separation data, cyan ink,
Magenta ink and yellow ink are applied. Also, if each ink is applied in an amount larger than the color separation data, an amount of white ink corresponding to the color difference is applied to the pixel.On the other hand, the color difference line buffer When the color difference value stored in 58 is less than a predetermined value, the paper feed pulse motor 1
The paper is fed by the first line, and the next line is recorded in the same way. Then, the process ends when all of the given color separation data has been recorded.

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, in the above-mentioned embodiment, there are four ink nozzles: white, cyan, magenta, and yellow, and the first recording uses three colors of ink, cyan, magenta, and yellow, and when recoating, cyan, magenta, and yellow inks are used. In addition to the three colors of , yellow, white ink is also used, but black ink may be used for coating, or inks of more colors may be used. Furthermore, the ink nozzles are not limited to one set of four-color ink nozzle combinations shown in the embodiment, but may include a plurality of similar ink nozzle combinations.

〔Effect of the invention〕

As is clear from the detailed description above, according to the present invention, there is no need for initial settings for color correction processing, and the process is performed for each given pixel without being affected by changes in the color of the base of the recording paper. Color separation data can be accurately reproduced for each pixel.

[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 is a schematic diagram of the colorimeter head and colorimeter nozzle. A schematic configuration diagram, FIG. 4 is a block diagram for explaining a control means for determining control data for the amount of ink adhesion. 4... Ink ejection head, 5... Colorimeter head, 6... White ink nozzle, 7... Cyan ink nozzle, 8... Magenta ink nozzle, 9... Yellow ink nozzle, 10... Recording paper, ■3... Colorimeter nozzle, 14.15.16.17... 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... Illumination generating part, 42 ...Fiber for sample illumination, 43...Fiber for sample measurement, 44.45.46
...filter, 47,48.49...photoelectric conversion section,
51... Interface section, 52... Line buffer for input data, 53... RAM, 54... RO
M. 55... CPU, 56... Recording signal source, 57...
Analog/digital converter, 58...color difference line buffer.

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 or a colorimeter for measuring the recorded color of a pixel to which toner is attached and recorded; and a control data creation means for determining control data for the amount of redeposition of ink or toner from the colorimetric results of the colorimeter; A color printer comprising: an adhering means for re-adhering ink or toner to the recorded pixels according to control data. 2. The method according to claim 1, wherein the adhering means adheres white or black ink or toner to the recorded pixels in addition to at least three colors of ink or toner: cyan, magenta, and yellow. color printer.