JPS6257142B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color image recording apparatus that records a color image on a recording material based on a plurality of color component signals.

Conventionally, when reading an original color document and forming a color image on recording paper using an inkjet recording device, for example, yellow, magenta, and cyan inks are ejected from different ink nozzles to print the ink onto the recording paper. Various methods have been proposed for reproducing color recorded images that are faithful to the original color original, depending on the degree of superimposition of ink dots or the degree of arrangement of ink dots of each color.

However, the reflection density of the recording paper before ink recording is not the same depending on the texture of the base material of the recording paper.

Therefore, for example, a recorded image recorded with ink of each color on lightly colored recording paper will have a different color reproduction than a recorded image recorded on ordinary recording paper with a white base. .

The present invention has been made in view of the above points, and an object of the present invention is to record a good color image with good color balance that is not affected by the background color of a recording material. an input means; a processing means for taking in and processing a plurality of color component signals input from the input means in parallel; and recording a color image on a recording material based on the plurality of color component signals from the processing means. a color image recording apparatus having a recording means, comprising a detection means for detecting a base color of the recording material on which a color image is recorded by the recording means and outputting a plurality of color component signals representing the base color; The processing means expresses a plurality of color component signals input from the input means and the base color output from the detection means in order to record a constant color image on the recording material regardless of the base color of the recording material. The present invention provides a color image recording device including a correction memory that simultaneously outputs a plurality of corrected color component signals using a plurality of color component signals as addresses.

Hereinafter, the present invention will be explained based on examples.

FIG. 1 is a schematic diagram of an embodiment of an apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes a reading/recording drum, on which an original color original 2 and recording paper 3 are wound. Reference numeral 4 denotes a drive motor for rotating the rotating drum 1 in the direction of arrow A in FIG. 5 is a reader that separates the original color original 2 into each component of blue (B), red (R), and green (G), and 6 is a reader that separates the reflection density of the recording paper 3 into R,
This is a reader that separates colors into three colors, G and B.

7 is an ink nozzle for forming a recorded image by ejecting ink of each color of yellow (Y), magenta (M), and cyan (C) onto the recording paper 3 wound around a drum; is fixed on the same recording head 8.

The reader 5 and the recording head 8 are fixed on a movable support base 9, and are configured to reciprocate in the direction of the drum rotation axis as the wire 10 moves linearly.

Therefore, the reader 5 and the recording head 8 evenly scan the original color original 2 and the recording paper 3 wrapped around the drum by the drum rotation and the linear movement of the support base 9 in the direction of the drum rotation axis. It is possible.

Reference numeral 11 denotes a pulse motor, and as the pulse motor 11 rotates, a pulley 12 fixed to the rotating shaft of the pulse motor 11 rotates. As the pulley 12 rotates, the pulley 13 and the wire 10 wound around the pulley 12 move linearly, and the wire 1 is moved by the retaining plate 14 connecting the wire 10 and the support base 9.
0 and the support stand 9 are structured so that they can interlock with each other.

The linear movement of the support base 9 in the direction of the drum rotation axis is as follows:
This can be done smoothly by the rail 15 and slider 16.

The reader 5 evenly scans the original color document wrapped around the drum 1 by rotating the drum 1 and linearly moving the support base 9, and scans the original color original wrapped around the drum 1 using red, blue, and green lights placed on the reader. The detection means detects a spot (usually 60 mm in diameter) on the original color document and outputs R, G, and B signals.

Similarly, the amounts of R, G, and B reflected light from the recording paper 3 wound around the recording paper drum before recording with ink are read by the R, G, and B light detection means of the reader 6. , output the respective signals. The R, G, and B photodetection signals output from the readers 5 and 6 are processed by a color signal correction control means 17.
The signals are converted into ink ejection signals of each color of Y, M, and C, which are blocked by the ink nozzle 7, and each ink droplet of Y, M, and C is printed on the recording paper 3 by the ink nozzle 7, resulting in a recorded image. is formed.

Figure 2 shows the blank parts of high-quality paper and rough paper, and C
3 is a graph showing the spectral reflectance of a portion printed with the ink of FIG.

In Figure 2, a is the blank part of the high-quality paper, b is the blank part of the rough paper, c is the part where C ink is printed on the high-quality paper, and d is the spectral reflectance of the part where C ink is printed on the rough paper. It is.

As shown in FIG. 2, the amount of reflected light in the white portion and the amount of reflected light in the printed portion of the C ink are significantly different between high-quality paper and rough paper. Although not shown, M, Y
The same applies to the ink printed portion.

Therefore, if the same ink is printed on recording sheets having different spectral reflectances, the color reproduction of the recorded images will naturally differ.

The present invention has been devised to overcome the above-mentioned drawbacks.

That is, a color image printed on rough paper using Y, M, and C color inks is an image shifted to a longer wavelength range when compared to a color image printed on high-quality paper.

To make a color image formed on rough paper the same as a color image formed on high-quality paper, it is sufficient to correct the shift of the color image formed on rough paper into the long wavelength range.

That is, the correction is made such that the amount of ink printed for each color of Y, M, and C is made stronger in the short wavelength region.

FIG. 3 is a circuit diagram for realizing the above-described correction.

101 to 103 are R, G,
B detection photo sensor detects each R, G, and
The photocurrent of the sensor changes depending on the amount of B reflected light. 104 to 106 are preamplifiers that convert the photocurrent of the sensor into voltage and amplify the signal voltage;
The amplified color component signals are supplied to analog-to-digital converters (AD converters) 107 to 109.

AD converters 107 to 109 are preamplifiers 104
The input voltage value from ~106 is converted into a 2-bit binary code.

That is, when the voltage value output from the preamplifiers 104 to 106 is 0, a digital signal encoded as [0, 0] is output from the AD converters 107 to 109, and is output from the preamplifiers 104 to 106. If the voltage value is equal to or higher than V, the encoded digital signal of [1, 1] is sent to the AD converters 107 to 10.
It is output from 9.

R ₂ output from AD converters 107 to 109,
The respective G ₂ and B ₂ signals are applied to a color correction converter 119.

110 to 112 are R, G,
Color original Figure 1 3 with the Naoto sensor for B detection.
This is a detector whose photocurrent changes depending on the amount of reflected light of each R, G, and B color component.

113 to 115 convert the photocurrents of the sensors 110 to 112 into voltages and amplify the signal voltages.The color component signals amplified by the amplifiers are sent to the AD converter 1.
16 to 118.

The AD converters 116 to 118 are the AD converters 1
Similar to 07-109, the amplifiers 113-115
The input voltage value is converted into a 2-bit binary code.

R ₁ output from AD converters 116 to 118,
The B ₁ and G ₁ signals are applied to a color correction converter 119.

The color correction converter 119 is composed of a read-only memory (ROM) whose address is each value code of R ₁ , G ₁ , B ₁ , R ₂ , G ₂ , and B ₂ from the AD converter. , its output signal
Co, Mo, Yo are conversion formulas here It has been patterned in advance to satisfy
Output via ROM.

The memory configuration of the ROM outputs Ci, Mi, and Yi in equation (2). a first memory section with a 384-bit configuration;
A second memory section with a 384-bit configuration that outputs Co', Mo', and Yo' in equation (3), and a third memory section with a 96-bit configuration that outputs Co, Mo, and Yo in equation (1). It's summery.

Output from the color correction converter 119,
Each color component signal of Co, Mo, and Yo is sent to the drive circuit 1.
20 to 123, the signal is applied to the ink jet nozzle shown in FIG. .

When the relative outputs of the amplifiers 104 to 106 have the characteristics shown in FIG.
is output from the second memory section of the color correction converter 119 when recording on high-quality paper with the characteristics of
The values of each signal of Co′, Mo′, and Yo′ are Co′〓
Mo′〓Yo′, and no mutual correction of the Co, Mo, and Yo signals output from the third memory section of the color correction converter 119 is performed by the Co′, Mo′, and Yo′ signals. The color image formed on the recording paper is faithfully reproduced based on the color component signals read by the sensors 110 to 112.

On the other hand, when recording on rough paper having the characteristics shown in _{FIG .} The value of ,Y ₂ is
From formula (3), R ₂ < G ₂ < B ₂ and AD converters 107 to 1
09, the respective values of Co', Mo', and Yo' output from the second memory section of the color correction converter 119 have a relationship of Co'<Mo'<Yo', The values of Yo′, Mo′, and Co′ output from the third memory section are corrected according to equation (1) so that Co>Mo>Yo compared to when recording on high-quality paper. , the color correction converter 119 outputs a corrected signal.

In other words, each of these corrected Co, Mo, and Yo signals becomes a signal in which the shorter wavelength range is emphasized than the original Ci, Mi, and Yi signals, and the drive circuit 120
~121.

Therefore, according to these Yo, Mo, and Co signals, Y, M, and C inks were ejected from the inkjet nozzles in FIG. 1 through the drive circuits 120 to 121 to record on the recording paper. The image is an image in which the number of recorded dots per unit area is greater in the order of C, M, and Y than when recorded on high-quality paper.

In other words, an image recorded on rough paper has a color reproduction that is no different from an image recorded on high-quality paper.

In the present invention, the density of the recorded image with each color ink is determined by the number of recorded dots per unit area, but it is also possible to control the density of each color of the recorded image by selectively ejecting ink from nozzles with different orifice diameters. It is also possible to control the color density of each of the recorded images by selecting a plurality of nozzles that eject color inks of different densities.

Furthermore, in the present invention, a method has been proposed in which a sensor for reading the original document and a sensor for detecting the reflection density of the recording paper are provided separately. It is also possible to realize this with the same sensor, and in this case, the signal that detects the reflection density of the recording paper can be easily realized by using a storage means.

In the embodiments of the present invention, the color correction conversion circuit is implemented using read-only memory, but it may also be implemented using volatile random access memory (RAM). This can be easily realized using a configuration that stores RAM and data.

As described above, according to the present invention, it has become possible to reproduce a good recorded color image by eliminating variations in recorded reproduced images due to differences in the material of the recording paper and differences in the color of the base of the recording paper.

Further, according to the embodiments of the present invention, even when recording is performed after partially color-coating the recording paper in advance, it has become possible to form a recorded image with good color balance.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram for explaining an embodiment of the present invention. FIG. 2 is a graph showing reflection density depending on the material of recording paper. FIG. 3 is a circuit diagram for explaining the circuit in the present invention. FIG. 4 is a graph showing the sensitivity characteristics of the reading sensor. DESCRIPTION OF SYMBOLS 1... Rotating cylindrical drum, 2... Color document, 3... Recording paper, 5... Color document reader, 6... Recording paper reader, 7... Recording inkjet nozzle, 8... Recording head.

Claims (1)

[Scope of Claims] 1. An input means for inputting a plurality of color component signals, a processing means for taking in and processing the plurality of color component signals input from the input means in parallel, and a plurality of colors from the processing means. A color image recording apparatus having a recording means for recording a color image on a recording material based on a component signal, the recording means detects a base color of the recording material on which a color image is recorded, and the base color is determined by detecting the base color of the recording material on which the color image is recorded. The processing means includes a detection means for outputting a plurality of color component signals representing a plurality of color component signals inputted from the input means in order to record a constant color image on the recording material regardless of the base color of the recording material. A color image recording device comprising a correction memory that simultaneously outputs a plurality of corrected color component signals using a color component signal and a plurality of color component signals representing a base color output from the detection means as addresses. Device.