JP2715590B2 - Color printer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color printer, and more particularly to a color printer that can accurately reproduce 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 recording pixels for each pixel based on color separation data obtained for each pixel, and cyan,
Each recording color is formed by a combination of magenta and yellow,
Color printers for creating color images have been developed. In such a color printer, color correction processing and the like are performed on the given color separation data for each pixel, and then cyan, magenta, and yellow inks are applied to recording paper. As the color correction processing, for example, as shown in the following equation (1), multiplication of color image color separation data by a color correction coefficient is performed to obtain adhesion amount control data for each ink.

· R, G, B: color image color separation data · C, M, Y: cyan, magenta, adhesion amount control data · a _ij of each ink of yellow (i, j = 1~3): color correction coefficient [Invention However, the inaccuracy of the color correction processing such as the error of the color correction coefficient at the time of the initial setting, the fluctuation over time after the initial setting, and the color reproducibility due to the fluctuation of the base color of the recording paper. There has been a problem that color separation data of each pixel cannot be accurately reproduced due to deterioration or the like.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a color printer that can accurately reproduce color separation data provided for each pixel.

[Means for solving the problem]

In order to achieve this object, the color printer of the present invention forms a color image by attaching at least three colors of ink or toner of cyan, magenta, and yellow to recording paper in accordance with given color separation data for each pixel. In a color printer, colorimetric means for measuring the recording color of a pixel on which the ink or toner has been adhered and recorded, and control for determining control data of the reattachment amount of ink or toner from the colorimetric result of the colorimetric means It is configured to include data creating means and attaching means for attaching ink or toner again to the recorded pixels according to the control data.

[Action]

The color printer according to the present invention having the above-described configuration forms recording pixels by adhering at least cyan, magenta, and yellow inks or toners on recording paper in accordance with the provided color separation data for each pixel. The control means creates control data for the re-adhesion amount of ink or toner based on the result of the color measurement of the recording color of the recording pixel by the color means. Again. For this reason, the color separation data for each given pixel can be accurately corrected for each pixel without being affected by the inaccuracy of the color correction processing, the fluctuation over time, the fluctuation of the background color of the recording paper, and the like. Can reproduce colors.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic perspective view showing one embodiment of the color printer of the present invention. In FIG. 1, a color printer according to the present invention is slidably mounted on a sliding shaft 1, and has an ink adhesion moving along the sliding shaft 1 by a screw shaft 3 which is rotationally driven by a head carry pulse motor 2. An ink ejecting head 4 as a means, a colorimeter head 5 as a colorimetric means connected to and moving simultaneously with the ink ejecting head 4, and a recording paper in a direction perpendicular to the moving direction of the ink ejecting head 4. And a paper feed roller 12 driven by a paper feed pulse motor 11 for feeding the paper 10. The ink jet head 4 has a white ink nozzle 6, a cyan ink nozzle 7, a magenta ink nozzle 8, and a yellow ink nozzle 9 with their axial directions parallel to the same direction and on a straight line parallel to the axial direction of the sliding shaft 1. It is arranged in. Further, ink supply tubes 14, 15, 16, and 17 for supplying corresponding inks are connected to these ink nozzles. The colorimeter head 5 is provided with a colorimeter nozzle 13.
The colorimeter nozzle 13 is located on the same line as the direction in which the ink nozzles 6, 7, 8, 9 are arranged.

FIG. 2 is a schematic configuration diagram of the ink nozzle shown in FIG. Since the configurations of the ink nozzles 6, 7, 8, and 9 are all the same, FIG. 2 illustrates the cyan ink nozzle 7 as an example. In FIG. 2, the cyan ink nozzle 7 is connected to a cyan ink tank 21 by a cyan ink pressurizing device.
A piezoelectric element for vibrating the pressurized cyan ink 23 sent through the cyan ink supply tube 15 by 22
24, a cyan nozzle 25 for extruding the 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 deflection electrode for deflecting the cyan ink particles 27. A deflection electrode 29 and a groove 30 for cyan ink are provided. The piezoelectric element 24 is a high-frequency power supply 31
The high-frequency power supply 31 is connected to the charging electrode 28 via a recording signal source 56 described later. The deflection electrode 29 is connected to a DC high voltage source 32.

FIG. 3 is a schematic configuration diagram of the colorimeter head 5 and the colorimeter nozzle 13. In FIG. 3, a colorimeter head 5 is shown.
The colorimeter nozzle 13 has a sample illumination fiber 42 for guiding the light emitted from the illumination generator 41 to the tip of the colorimeter nozzle 13 and irradiating the recording paper 10 with the ink applied thereto. Recording paper out of the light emitted from 42
A sample measurement fiber 43 for guiding the light reflected by 10 to a photoelectric conversion unit described below, and a red filter 44 for color-separating light transmitted through the sample measurement fiber 43,
A green filter 45 and a blue filter 46, and a red photoelectric conversion unit 47, a green photoelectric conversion unit 48, and a blue photoelectric conversion unit 49 that convert light transmitted through these filters into electric signals, respectively, are provided. Then, the electric signal converted by each photoelectric conversion unit is converted into an analog signal described later.
After being converted to a digital signal by the digital converter 57,
The CPU 55 compares the color separation data of each pixel stored in the line buffer for input data with the color separation data, and stores the result of calculating the color difference in the line buffer 58 for color difference.

FIG. 4 is a block diagram for explaining a control means for determining control data of the ink adhesion amount. 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 the color separation data for each pixel captured by the interface unit 51, and a RAM 53. And a CPU 55 for performing signal processing according to the contents of the ROM 54, a recording signal source 56 for controlling the charging of ink in accordance with the input color separation data for each pixel, a line buffer 52 for input data and an analog / digital converter 57 in the CPU 55. A color difference line buffer 58 for comparing the obtained color separation data for each separation color and storing a result calculated based on the comparison is provided.

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

Here, the application operation will be described in more detail using cyan ink as an example. Note that all the other color inks are applied to 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. The nozzle 25 is vibrated by a piezoelectric element 24 that is excited by a high-frequency voltage supplied from a high-frequency power supply 31. Therefore, the ink column 26 passing through the nozzle 25 also vibrates, and the ink column 26 extruded from the nozzle 25 is continuously separated into ink particles 27 having a uniform size and a constant flying speed. When the ink particles 27 thus separated are formed on the recording paper 10, the 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 signal is applied. The particles 27 become charged recording particles 33. When the recording particles 33 pass through an electrostatic field formed between the deflection electrodes 29,
The recording sheet 10 receives a deflecting force in accordance with the charge amount and adheres to a predetermined position on the recording sheet 10. On the other hand, when the ink particles 27 are not applied on the recording paper 10, the recording signal voltage is not applied to the charging electrode 28 based on the cyan data sent to the recording signal source 56, and the ink particles 27 are charged. There are no unnecessary particles 34. Even if the unnecessary particles 34 pass through the electrostatic field formed between the deflecting electrodes 29, they do not receive any deflecting force. There is no. The unnecessary particles 34 that have been prevented from flying by the cyan groove 32 are collected as unnecessary ink in the cyan ink tank and reused.

The above operation is repeated for the magenta ink and the yellow ink while moving the ink ejecting head along the sliding shaft 1 by the head carry pulse motor 2, thereby recording one pixel. After the yellow ink is applied, the colorimeter nozzle 13 is located on the recorded pixel, and the color of the pixel is measured. That is, first, the light emitted by the illumination generating unit 41 is applied to the recorded pixels on the recording paper 10 through the sample illumination fiber 43. The light reflected by this pixel is sent to the red filter 44, the green filter 45, and the blue filter 46 through the sample measuring fiber 43, and the light that has passed through each filter and has been color-separated is the corresponding red photoelectric filter. The conversion unit 47, the green photoelectric conversion unit 48, and the blue photoelectric conversion unit 49 convert the electric signal into an electric signal. Then, the electric signal converted by each photoelectric conversion unit is converted into a digital signal by an analog / digital conversion unit 57, and then compared with color separation data for each pixel stored in an input data line buffer 52 by a CPU 55. The result of the color difference calculation is stored in the color difference line buffer 58.

As described above, while the input color separation data and the color difference between the recorded pixels are stored in the color difference line buffer 58, the above operation is repeated for each pixel in the order of cyan → magenta → yellow to record one line on the recording paper. Is recorded. After recording the pixels for one row, the CPU 55 checks whether or not the color difference value stored in the color difference line buffer 58 is equal to or greater than a predetermined value. Investigate whether the reproduction of the decomposition data is insufficient,
For a pixel having a color difference value equal to or greater than a predetermined value, ink is applied again based on the color difference stored in the color difference line buffer 58. At this time, when each ink is applied less than the color separation data, cyan ink, magenta ink, and yellow ink are applied. When each ink is applied more than the color separation data, an amount of white ink corresponding to the color difference is applied to the pixel. on the other hand,
If the color difference value stored in the color difference line buffer 58 is less than the predetermined value, the paper is fed by the paper feed pulse motor 11 and the next line is recorded in the same manner. Then, the process ends when all the given color separation data are recorded.

The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the gist of the present invention. For example, in the above-described embodiment, there are four ink nozzles of white, cyan, magenta, and yellow. In the first recording, inks of three colors of cyan, magenta, and yellow are used. In addition to the three colors of yellow and yellow, white ink is also used, but black ink may be used for coating, and inks of more colors may be used. Further, the ink nozzles are not limited to a combination of the four color ink nozzles shown in the embodiment,
A plurality of similar ink nozzle combinations may be provided.

〔The invention's effect〕

As is apparent from the above description, according to the present invention, the initial setting of the color correction processing is not necessary, and each pixel provided without being affected by the fluctuation of the background color of the recording paper. The color separation data can be accurately reproduced for each pixel.

[Brief description of the drawings]

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 color meter head and a color meter nozzle. FIG. 4 is a schematic configuration diagram, and FIG. 4 is a block diagram for explaining a control means for determining control data of an ink adhesion amount. 4 ... head for ink jetting, 5 ... head for colorimeter, 6
...... White ink nozzle, 7 ... Cyan ink nozzle, 8 ...
... Magenta ink nozzle, 9 ... Yellow ink nozzle, 10 ... Recording paper, 13 ... Color meter nozzle, 14,15,16,1
7 ... Ink supply tube, 21 ... Cyan ink tank, 24 ... Piezoelectric element, 25 ... Cyan nozzle, 26 ... Cyan ink column, 27 ... Cyan ink particle, 28 ... Charging electrode, 29 ... Deflection Electrode, 30 ... Cyan ink groove, 41 ... Illumination generator, 42 ... Sample illumination fiber, 43 ...
Sample measuring fiber, 44, 45, 46… Filter, 47, 48, 49
... Photoelectric conversion unit, 51 ... Interface unit, 52 ... Input data line buffer, 53 ... RAM, 54 ... ROM, 55 ... CPU, 56 ...
Recording signal source, 57 ... Analog / digital converter, 58 ...
... Line buffer for color difference.

Claims (2)

(57) [Claims] 1. A color printer for producing a color image by attaching at least three colors of inks or toners of cyan, magenta and yellow to recording paper in accordance with given color separation data for each pixel, wherein the inks or toners are Colorimetric means for measuring the recording color of the adhered and recorded pixels, control data creating means for determining control data of the amount of re-adhesion of ink or toner from the colorimetric results of the colorimetric means, and according to the control data A color printer, further comprising: an adhering means for adhering ink or toner to the recorded pixels. 2. The image forming apparatus according to claim 1, wherein said attaching means includes at least cyan, magenta, and yellow inks or toners.
2. The color printer according to claim 1, wherein white or black ink or toner is applied to the recorded pixels.