JPH0216875A - Color image reader - Google Patents

Abstract

PURPOSE:To reduce the hue difference of specified color in an original by providing a non-volatile memory to hold a constant about ink quantity and an arithmetic operating means which forms the ink quantity by using the combination of the constants read from said memory and supplies it to a color/ink quantity conversion table. CONSTITUTION:In the re-scanning of the original, a color signal to show the light intensity of a specified wavelength in reflected light is detected by an image sensor 28, and is formed by letting pass through A/D converters 33 to 3, 5, shading circuits 36 to 38 under the control of a CPU 30, and a principal color range is determined. A ROM 50 holds previously the combination of the constants to set the information of the ink quantity so that the hue difference between prescribed color expressed by the color signal and the color sample of uniform space becomes smaller than the hue difference related to other color as keeping it corresponding to the prescribed colors different from each other. The CPU 30 operates the information related to the ink quantity on the basis of the read out combination of the constants, end supplies it to the conversion table (RAMs 40 to 42 and an adder 43) of a color masking circuit 39. If the image is printed according to this ink quantity, the hue difference never occurs.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is included in a color image reading device, specifically a digital color copying machine, etc., and is used to generate color density signals representing the intensities of red light, green light, and blue light, respectively. A color image reading device generates a signal representing the amount of ink of each color of cyan, magenta, and yellow based on these color signals.

[Prior Art] As a conventional color image reading device of this type, one shown in FIG. 11, for example, is known.

In FIG. 11, 1 is a document on which a color image is drawn, and this document 1 is irradiated with white light from a light source 4 that receives driving force from a motor 2 and moves in the direction of arrow 3, and the reflected light is A plurality of CCDs arranged approximately perpendicular to the three arrow directions
An image sensor 5 composed of elements and the like converts the intensity of each of the red, green, and blue colors of the reflected light into analog color signals R, G, and B each representing a voltage value.

These analog color signals R, G, and B are converted into density values of each color from the reflection intensity of each color by a logarithmic conversion circuit 6, and outputted as color density signals. For example, if the value of reflectance is R
f, and the value of the color density signal is D, the logarithmic conversion circuit 6 calculates D=-1ogRf.

These color density signals are converted from analog values to digital values by the A/D converter 7, and are converted into digital color density signals DR.
'DG'DB" is sent to the shading circuit 8.

The shape ink circuit 8 corrects errors caused by uneven light emission of the light source 4 and irregularities in the characteristics of the CCD elements constituting the image sensor 5, and then outputs the corrected digital color density signal DR"DG"DB''. The signal is supplied to the masking processing circuit 9.

The masking processing circuit 9 is a digital color density signal DR.
Output signals C, M, and Y representing the amounts of ink of each color of cyan, magenta, and yellow are formed based on DG"DB", and a halftone processing circuit 10 that performs dither processing etc. on these output signals C, M, and Y is generated. and a printing device (not shown).

Reference numeral 11 denotes a microcomputer unit (MPU) that controls each of the circuits 7 to 10 and the motor 2.

”- As a specific example of the masking processing circuit 9, as disclosed in Japanese Patent Laid-Open No. 60-216670, a coefficient ans-a22 representing the characteristics of printing ink, etc.
It is composed of a plurality of read-only memories that fixedly store the multiplication results for each color with digital color density signals DR, DC, and DB, and an adder circuit that adds the outputs of these read-only memories.

In general, these coefficients aS! ] to a22 are set so that the hues of pixels printed for various color samples are close to each other. That is, specifically, in the uniform color space (L", ao, b"), the (L", ao, b") values for a large number of color samples and the (L"
The above coefficient a[l[
l''a22 is set.

△E 2 = Σ((L--L") 2+ (a"-a"
) 20(b”?J”) 2) ...(Formula 1) [Problems to be Solved by the Invention] However, in such a conventional color image reading device, its masking processing circuit 9 is the coefficient a
Squared error △E2 where the value of B~a22 is calculated using (Formula 1)
is set to the minimum value, so it is possible to get a natural impression from the printed image for originals that contain an average of various hues, but for originals with uneven hues (for example, , manuscripts that contain many images of the sea or sky, or manuscripts that mainly contain images of people) have a problem in that they cannot necessarily give a natural feel.

In order to solve this problem, the applicant has proposed a color scheme that selectively uses ink amount data to improve the reproducibility of the main colors in a document in a patent application filed on the same day as the present patent application. We are proposing an image reading device. However, in this case, it is not preferable to prepare a wide variety of data in order to selectively use the data regarding the amount of ink because it increases the storage capacity of the memory system.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a color image reading device that can obtain natural copied images even from originals with uneven hues without significantly increasing the storage capacity of a memory system.

[Means for Solving the Problems] The present invention selectively uses coefficients that improve the reproducibility of major hues in a document, and calculates data regarding ink amounts each time to avoid calculation deviations and create a natural image. It was developed with a focus on what can be achieved by a slight increase in storage capacity, and its gist is to scan an original and express the intensity of light at multiple specific wavelengths in the reflected light reflected from the original. a color signal forming section that outputs a plurality of color signals; a color signal forming section that holds data regarding a plurality of ink amounts corresponding to the plurality of color signals for each of the plurality of colors; A conversion table that outputs a plurality of signals each representing data regarding the amount, and calculating the amount of ink for any of the above colors based on the data regarding the amount of ink each represented by the plurality of signals output from the conversion table. an adder; for a predetermined color among the plurality of colors represented by the two color signals, the chromaticity difference between the color and a color sample in the uniform color space is smaller than the chromaticity difference with respect to other colors; A nonvolatile memory that stores a plurality of sets of constant keys for setting data regarding the amount of ink, each corresponding to a plurality of different predetermined colors, and a set of constants read from the nonvolatile memory. The color image reading device includes a calculation means for forming data related to the ink amount based on the ink amount and supplying the data related to the ink amount to the converter.

[Operation of the Invention] In the color image reading device having the above configuration, when calculating the amount of ink for an arbitrary color, one is selected from a plurality of constants stored in the non-volatile memory prior to scanning the document. , the arithmetic means uses the constant key II to form data regarding the amount of ink.

These data regarding ink clearness are sent to the conversion table by the calculation means and held in the conversion table.

Thereafter, when scanning of the document is started, a plurality of data regarding the ink amount corresponding to the color signal is read from the conversion table based on the plurality of color signals supplied from the color signal forming section.

In this way, when the data regarding the ink amount for any color is read out from the conversion table, the data regarding the ink amount is sent to the adder, and the adder calculates the ink amount for the above arbitrary color. calculate.

The calculation of the amount of ink is performed for each of the plurality of colors, and printing is performed, for example, according to the amount of ink related to the plurality of colors.

Here, the data regarding the ink amount can be selected such that the chromaticity difference between the predetermined color and the color sample in the uniform color space is smaller than the chromaticity difference regarding other colors.
In the printed image, the color deviation regarding the hue of the predetermined color is reduced.

[Example code] Embodiments of the present invention will be described below with reference to the drawings.

1 to 10 are diagrams showing a color image reading device and its control flowchart according to an embodiment of the present invention.

In these figures, reference numeral 21 denotes a document glass stand on which a document 22 on which a color image is drawn is placed.

When copying the original 22, the exposure lamp 23 and the first mirror 2
4. An optical system 29 composed of a second mirror 25, a third mirror 26, a lens 27, and an image sensor 28 connects the central processing unit (CPtJ) 3 to the original glass table 21.
The drive force is obtained from a motor 31 controlled by 0 to repeatedly move in the direction of arrow 32.

As the optical system 29 moves, the original 22 is irradiated with white light, and the reflected light is reflected by the first, second, and third mirrors 24.2.
5.26 and the lens system 27, and the image sensor 2
8. This image sensor 28 emits red light (R).
), green light (G), and blue light (B). Analog color signals R5G and B representing the intensities of the blue and blue components as voltage values, respectively.
is output.

The document 22 is scanned three times per document, and the reason for scanning each document three times is to print cyan ink based on the first scan, and print magenta ink based on the second scan. This is because printing is performed using ink, and printing using yellow ink is performed based on the third scan.

Analog color signal R output from the image sensor 28,
G, B are A/D converters 33.3 for each three scans.
At step 4.35, the analog value is converted into an 8-bit digital value and sent to shading circuits 36, 37, and 38 as digital color signals DR1DG and DB, respectively.

Shading circuit 36.37.3 is exposure lamp 23
After correcting errors caused by uneven light emission and variations in characteristics of the CCD elements constituting the image sensor 28, the corrected digital color signals DR, DG, and DB are supplied to the color masking circuit 39.

As shown in FIG. 3, the color masking circuit 39 converts a memory that can be read and written at any time (random access memory (hereinafter simply referred to as RAM)), which has an 8-bit address terminal and an 8-bit data input/output terminal, into a digital memory. It includes a configuration in which three color signals DR, DG, and DB are prepared respectively 40, 41, and 42, and the output signals of these rams 40, 41, and 42 are supplied in parallel to the input terminal of the adder 43. figure).

Further, the color masking circuit 39 includes, as will be described in detail later,
The above digital color signals DR, DG, DB are sent to each ram 7.
'Cyan ink is supplied to the address terminals of LO141 and LO142, respectively, and corresponds to the intensity of the red component, the intensity of the green component, and the intensity of the blue component of the reflected light represented by the digital color signals DR, DG, and DB. , data regarding each ink amount of magenta ink or yellow ink OR,
OG and OB are output to the adder 4-3.

The adder 43 receives data OR1○ regarding the amount of cyan ink, magenta ink, or yellow ink.
G50B are added to form output signals C1, M1, and ¥1 representing the amount of cyan ink, magenta ink, or yellow ink, respectively.

In this way, in this embodiment, only the ink amount of cyan ink, magenta ink, or yellow ink is calculated in one scan of the document 22.
．． The data in 42 must not be rewritten after the end of each scan until the start of the next scan.

To this end, as shown in FIG. selectors 47, 48, and 49 respectively, and the central processing unit 30 selects the coefficients based on coefficients ai+i+ to a22, which will be described in detail later, and is stored in a read-only memory (hereinafter simply referred to as ROM) 50 under the control of the central processing unit 300. Predetermined calculations are performed to calculate data regarding ink of different colors and transferred to the RAM 40.41.42.

Further, the output of the color masking circuit 39 is supplied to a printing device (not shown) through a binary/halftone processing circuit 51 that performs dither processing and the like.

The printing device is a powder developer transfer type electrophotographic copying machine that writes an image on a photoconductor using a laser beam and then develops it using a powder developer (toner).
Laser writing and development processes for each color are performed for each scan of the original, and after the third scan, the powder image formed on the photoreceptor is transferred onto transfer paper and recorded.

Therefore, in this embodiment, the optical system 29 and the A/D converter 3
3, 34, and 35 constitute a color signal forming section as a whole, and rams 40, 41, and 42 constitute a conversion table.

Next, data regarding the amount of ink held in the rams 40, 41, and 42 will be explained.

The data regarding the ink amount is the logarithm value of the calculation result on the right side when the digital color signals DR, DG, and DB are changed using the determinant shown below.

In addition, a[lil~ai! 2 is a constant coefficient determined in advance based on the spectral reflection characteristics, printing characteristics, etc. of the cyan ink used in the printing device (not shown), and al[] to a12 are the spectral reflection characteristics, printing characteristics, etc. of the magenta ink. It is a constant coefficient determined by Further, a2++'''a22 is a constant coefficient determined by the spectral reflection characteristics, printing characteristics, etc. of yellow ink.

These coefficients ai]l] to a22 are stored in the read-only memory 50 for a plurality of coefficients corresponding to a plurality of hues for which reproducibility is important, respectively, as will be described in detail later.

Furthermore, C, M, and Y indicate the amounts of cyan ink, magenta ink, and yellow ink, respectively.

Continuing with the explanation regarding the data regarding the amount of ink, when printing with cyan ink, the logarithm value of the calculation result of aiu+XDR when changing the value of the digital color signal DR is stored in RAM 40 and RAM 41. is stored as the logarithmic value of the calculation result of az+XDG when the value of the digital color signal DG is changed, and the logarithm value of the calculation result of ae2XDB when the value of the digital color signal DB is changed is stored in the RAM 42. remembered.

On the other hand, when printing with magenta ink, when the values of the digital color signals DR, DG, and DB are changed, a
The logarithmic values of the calculation results of +5XDR, a++XDG, and a+2XDB are held in RAMs 40, 41, and 42, respectively. Similarly, when printing with yellow ink, the values of digital color signals DR, DG, and DB are stored, respectively. a2eXDR, a2+XDG, a22 when changed
The logarithm value of each calculation result of XDB is Ram 40.41
．． 42, respectively.

When reading data regarding the ink amount from these rams 40.41.42, the rams 40.41.42 are switched to read mode in response to the write/read control signal W/H supplied from the central processing unit 30. The selectors 44 to 49 control the shading circuit 3 by bus control signals supplied from the central processing unit 30.
The digital color signals supplied from RAMs 6 to 38 are sent to RAM 40.
41.42 to the address terminals of rams 40.41.
Since the output signals of 42 are switched to be supplied to the adder 43, the output signals from the rams 40, 41, and 42 are output from the digital color signals DR, DG, and DB. Data regarding the amount of ink is output to the adder 43 from the data input/output terminal.

On the other hand, when writing data regarding the amount of ink to the rams 40, 41, 42, these rams 40, 41, 42 are switched to write mode, and the central processing unit 30 supplies data to the data input/output terminal via the data bus DB. Data regarding the new ink amount is sequentially written to the addresses appearing on the address bus AD.

An example of data regarding the amount of ink held in the rams 40, 41, 42 in this manner is shown in the table below.

The table below shows data regarding the amount of ink when ai+a:10110010 and the value of the digital color signal is changed from oooooooo to 11111111.

Note that such a multiplication table is a 1les a
[! It is also possible to obtain the signal C1 by preparing three types of rams 1 and ai+2 and adding the outputs of the rams 40, 41, and 42 as described above. Zunawaji, in FIG. 4, a multiplication table regarding ase is written in the RAM 40, and aZ+, aZ+, and RAMs 41 and 42, respectively.
Assume that a multiplication table regarding ao2 has been written.

In this case, after the signal ¥1 is obtained for the entire surface of the document as described above, the document is scanned again, and then the signal M1 is obtained, and then the signal C1 is obtained in the next scan.

However, in this case, it is necessary to use a different multiplication table from the one used to obtain Yl.

Of course, in this case, it is possible to prepare tables for yellow, magenta, and cyan before the first scan, and to switch the ram tables each time the output color changes. However, although each scan uses only an area of 256 bytes x 3, the RAM for the table is 256 bytes x 3.
This means that one with a capacity of 9 must be prepared.

In other words, 2/3 of the total capacity is an unused area.

In order to eliminate this waste, the contents of the table are rewritten for each scan as described above. If this rewriting is performed when the scanner returns, there is no need to set a particular time for rewriting the table. The configuration shown in FIG. 5 is for the CPU 30 to write a multiplication table to the RAM. This point has already been explained.

The data regarding the amount of ink read from each ram 71O1/'11.42 in the manner described above is supplied to the adder 43, where it is added up.

Therefore, the output signal output from the adder 43 for each document scan represents the amount of cyan ink, magenta ink, or yellow ink, and based on the output signal from the adder 43, the printing device (not shown) cyan color,
When magenta and yellow partial images are drawn and these partial images for each color are combined, the image drawn on the original document 22 is duplicated.

Next, a coefficient a for calculating data regarding the amount of ink
i! ++~a22 will be explained.

As mentioned above, the coefficient a[]1ll-a22 of this embodiment improves the reproducibility of a specific color compared to the reproducibility of other colors. b”) Squared error △E2 where the weight WK due to color k is multiplied between the (L’, ao, b’) value of the color sample in space and the (L” a” b”) value of the print color (See Equation 2) is selected from ao[] to a22 (hereinafter referred to as (a:+)).

△E2=ΣW(Lk'Lk"")2+(ak'
ab") 2+ (bb"bk")"t...
(Equation 2) The coefficients a[lil to a22 are for a specific color (for example, blue), and the coefficients are set so that the hue shift of the specific color is smaller than the hue shift of other colors.

Therefore, a plurality of sets of such coefficients (aWk) are prepared for each different hue and are stored in the read-only memory 50.

FIG. 8 is a block diagram showing the relationship among the ROM 50, CPU 30, and RAMs 40-42.

That is, for example, if a multiplication table corresponding to aee=10110010 is required, the ROM 50 stores the coefficient a.
Only i+e=10110010 is stored. However, the data actually required as a RAM table is a
o[+×0, ag3oX1, aBX2, ...
... aei+X255. This calculation is done on CPU30
The data is written to the RAMs 40-42.

At the time of printing, a specific silk is selected from a plurality of sets as will be described in detail later, and the central processing unit 30 selects a coefficient API that constitutes the different set.
+ to a22 are sequentially read out to calculate data regarding the amount of ink.

In this embodiment, the coefficient apse-a22 of each phase is stored in the read-only memory 50, so the storage capacity of the read-only memory 50 may be relatively small at about 6 bytes. If you directly store the data regarding the amount, each data will be 8 pits, 28X 6=1. 5 (, kilobytes) for each pair (a:J)k, which leads to an increase in the storage capacity of the read-only memory 50.

As shown in FIG. 1, the color image reading device according to this embodiment further includes shading circuits 36, 37, 38.
It has line rams 52, 53, and 54 connected in parallel to each other, and the outputs of these line rams 52, 53, and 54 are supplied to the data input/output terminal of the central processing unit 30.

These line rams 52, 53, 54 temporarily output the digital color signals DR, DG, DB output from the shading circuits 36, 37, 38 when selecting the silk (a, ,)k with a predetermined coefficient from a plurality of silks. is stored to provide data for central processing unit 30 to determine the dominant hue of document 22.

That is, when the user of the color image reading device according to this embodiment specifies the Briscan mode using a mode specifying switch (not shown) before copying the original 22,
In response to the Briscan mode signal transmitted via the communication system 55, the central processing unit 30 deactivates a printing device (not shown) and gives an operation command to the optical system 29 to start scanning the original 22. let

As the original 22 is scanned, the A/D conversion circuits 33, 34.
A digital color signal DR,
Since DG and DB are supplied, the central processing unit 30 forms a histogram of the hues in the original 22, determines the dominant hue of the original 22, and then determines the coefficient (a:J)k.

Note that when copying is started without specifying the Briscan mode, the hue coefficient directly specified by the operator or the average hue coefficient expressed by (Equation 1) is specified.

Next, the operation of this embodiment will be sequentially explained with reference to the flowcharts shown in FIGS. 6 and 7.

When the operator desires to make a color copy of the original 22, places the original 22 at a predetermined position on the original glass table 21, and selects the Briscan mode, the central processing unit 30 performs step S1.
The selection of the Briscan mode is detected (Y), and the Briscan subroutine SRI, which will be described in detail later, is executed, but if the judgment result in step S1 is No (N), the coefficient data for the specific hue is specified. If the judgment result in step S2 is YES (step S2), the judgment result in step S2 is YES (
In the case of Y), the hue specification switch is scanned to read the hue specified by the operator, and based on the switch operation, the silk corresponding to the operated switch is selected from a plurality of coefficient sets (step S3).

On the other hand, if the hue designation switch is not operated, an averagely optimized set of coefficients determined according to (Equation 1) is selected (step S4).

When the Briscan routine SRI starts, as shown in FIG. 7, the central processing unit 30 initializes the histogram set in a predetermined memory space (step S5).
Next, the exposure lamp 230 is instructed to turn on (step S
6).

The motor 31 starts normal rotation in response to an instruction from the central processing unit 30, and starts blisscanning of the original 22 (step S7).

With the start of this briscan, suitably corrected digital color signals DR, DG, and DB are output from each shading circuit 36, 37, and 38.

Therefore, the central processing unit 30 has line rams 52, 53
．． The color associated with each pixel is read from 54 (step S8
), it is determined which of the spaces R1, which is obtained by dividing the uniform color space into a predetermined number, the color of the read pixel belongs to in step S9.
), are added to the histogram (step 510).

In this way, while creating a histogram, bliscanning is executed for the entire range of the document 22 (step 8).
8 to 510), wait for the judgment result in step Sll to be YES.

Eventually, when the scanning of the entire range of the original 22 is completed, the judgment result in step Sll becomes YES (Y), so the central processing unit 30 gives a reversal instruction to the motor 31 to return the optical system 29 to the initial position (step 512).

Control then returns to the main routine shown in FIG.

When the histogram is thus completed, the central processing unit 30 determines the hue that appears most frequently based on the histogram, and determines the phase of the coefficient corresponding to the hue (step 513).

In this way, once the coefficients for the dominant colors of the original 22 are determined, the central processing unit 30 executes the coefficients (ai
j) Calculate data regarding cyan ink using k and write these to ram 40.41.42 (step 514).

Therefore, this central processing unit 30 and step S14 realize a calculation means.

When the copy start switch is operated, the central processing unit 30 instructs the exposure lamp 23 to turn on, instructs the motor 31 to rotate forward, and starts the first scan (step 515).

When the first scan is completed in this manner, the central processing unit 30 repeats steps S14 and S15 to calculate data related to magenta ink, and performs the second scan.

Similarly, when printing with magenta ink is completed, steps 514 to S15 are repeated again to perform printing with yellow ink.

Here, FIGS. 9 and 10 represent R0 shown in FIG. 8 above.
A flowchart for obtaining data actually required as a RAM table in relation to the M50, the CPU 30, and the RAMs 40 to 42 is shown.

For example, if a multiplication table corresponding to ag3++:10110010 is required, the coefficient a+u+
Although only =10110010 is written down, the data actually required as a RAM table is ai]oX O
-, aezX 1, aheX2, --- a[][
l x 255. This shows the flow when the CPU 30 performs this calculation and writes it to the RAMs 40 to 42. In this case, the ROM 50 contains multiple coefficients aall to a.
22 is stored. At this time, the subscript 1 in the flow determines which silk a22 to a22 is selected by the selection means.

First, in step P1, it is determined whether the print color is yellow (Y). If it is yellow, proceed to step P2 and apply (a 2es a [
Set the data of H1aθ2).

If it is not yellow, the process proceeds to step P3, where it is determined whether the print color is magenta (M).

If it is magenta, in step P4 (X, Y, Z
), set the data of (alt!, a IIs a 12).

If it is not magenta, the printing color is cyan (S), so
As cyan data, in step P5, (X
, Y, Z) with the data of (a28, a2+, a22).

The data (X, Y, Z) set in these steps P1 to P5 are written to the ram RAMs 40 to 42, respectively, in the following steps P6 to pH.

That is, in step P6, the RAM 40 is selected and the data of each X is set in W. Next, in step P7, a RAM write processing routine (RAMWRT,
Steps Q1 to Q5 in FIG. 10 are executed and written.

Next, in steps P8 and P9, the RAM 41 is selected and Y data is written in W, and further, in step PI
At O1pH, ram 42 is selected and Z data is written in W.

In the RAMWRT process shown in FIG. 10, after initializing the RAM table address C (step Ql), data D is written to each address (steps Q2 to Qδ).
.

That is, in step Q2, C*W is set to D, and in step Q3, this D is written to the ram table address C. In step Q4, it is determined whether C is 255 or not, and if it is not, it is incremented (C+1
) The process returns to step Q2, and if it is, the process returns to the main routine.

In the above embodiment, the data regarding the amount of ink held in the rams 40, 41, and 42 is rewritten every time the document is scanned, but it is also possible to store data regarding the amount of ink for three colors in a large-capacity ram. You can leave it there.

Further, in the above embodiment, explanations regarding the positive and negative values of aiu+ to a22 have been omitted, but since some coefficients may be negative, it is recommended to use an adder 43 of a type capable of signed addition. preferable. At this time, as the coefficient data to be written to the RAM, the most significant bit should be the sign bit and the complement should be written in advance, or since it is known in advance which data will be a negative number,
A sign control circuit is inserted between the RAM 40, 41, 42 and the adder 43, and for negative coefficients, the central processing unit 30 controls the sign control circuit to perform a negative operation W. Yes.

In this specification, the terms ink and ink amount are used, but this includes the powder developer (toner) used when a powder image transfer type electrophotographic copying machine is used as a printing device. .

[Effects of the Invention] As described above, according to the present invention, it is possible to obtain the effect that an original document having a characteristic hue can be copied in a natural state, and also to copy a plurality of i stored in a non-volatile memory.
Select one of the coefficients of ff (a:4'lk), calculate the data regarding the amount of ink based on tifl of the coefficient, and use these data to determine the amount of ink. Copies can be made with less deviation in the hue of a specific color, and since only the coefficients are stored in non-volatile memory, the reduction in the deviation in the hue of a specific color can be achieved with a relatively small increase in storage capacity. This effect can also be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram showing the configuration of a color image reading device according to an embodiment of the present invention, and FIG. 2 is a block diagram showing the detailed configuration of an optical system of the color image reading device according to an embodiment. FIG. 3 is a plan view showing the pin arrangement of the ram used in the masking processing circuit according to one embodiment;
The figure is a block circuit diagram showing a schematic configuration of a color masking circuit according to one embodiment, FIG. 5 is a block circuit diagram showing a detailed configuration of a color masking circuit according to one embodiment, and FIG. 6 is a main routine of one embodiment. Flowchart, FIG. 7 is a flowchart showing the prescan subroutine of one embodiment, FIG. 8 is a block diagram showing the relationship between ROM, CPU, and RAM according to one embodiment, and FIG. 9 is a flowchart showing the relationship between ROM, CPU, and RAM according to one embodiment. FIG. 10 is a flowchart showing a RAM write processing routine according to an embodiment. FIG. 11 is a block circuit diagram showing the configuration of a conventional color image reading device. 21 ・ ・ ・ 22 ・ ・ ・ 28 ・ φ ・ 29 ・ ・ ・ 30 ・ ・ ・ 33～35 36～38・ 39 ・ ・ ・ ・ 40～42 ・ 43 ・ ・ ・ ・ 50 φ ・ ・ ・ 52～54 ・・ ・Original glass stand, ・Original, ・Image sensor, ・Optical system (color signal forming section), ・Central processing unit, ・A/D converter (color signal forming section), ・Shading circuit, ・Color masking circuit,・RAM (conversion table), ・Adder, ・Read-only memory (non-volatile memory), ・Line RAM. Patent applicant Minolta Camera Co., Ltd. Agent
Patent attorney Kiyoshi Kuwai (1 other person) Figure 9 Figure 10

Claims (1)

[Claims] (1) A color signal forming unit that scans a document and outputs a plurality of color signals each representing the intensity of light of a plurality of specific wavelengths in the reflected light reflected by the document; a conversion table that holds data regarding a plurality of ink amounts for each of a plurality of colors of ink, and outputs a plurality of signals each representing data regarding an ink amount corresponding to the color signal based on the plurality of color signals; an adder that calculates the amount of ink for one of the above colors based on data regarding the amount of ink each represented by a plurality of signals output from the color image reading device, the color image reading device comprising: A set of constants for setting the data regarding the ink amount is mutually set so that the chromaticity difference between a predetermined color among the plurality of colors and a color sample in a uniform color space is smaller than the chromaticity difference regarding other colors. a non-volatile memory that stores a plurality of sets corresponding to different predetermined colors, and a set of constants read from the non-volatile memory to form data regarding the amount of ink; A color image reading device comprising: arithmetic means for supplying data to the conversion table.