JPH09261418A - Image forming method, image processing method and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent forgery concerning widespread kinds of images by forming an image by a reading means of low photodetective sensitivity in a wave length band at the peak of spectral reflective characteristic of a recording agent used for an original. SOLUTION: An image original printed by using a first recording agent with the peak of spectral reflective characteristic in a first wave length band is optically read by using the reader of low photodetective sensitivity with respect to light at the first wave length band to form an image on a recording medium based on a read image signal. The first recording agent includes ink having the spectral reflective characteristic having a peak in a wave length 500±25nm. The spectral transmissivity characteristic of the color resolving filter of a copier, etc., has a peak characteristic basically near 450nm, 550nm and 650nm in each of R, G and B. Consequently, as the color of the copy changes more than that of a printed original at the time of copying a printed object printed with the first recording agent, forgery is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method, an image processing method and an apparatus thereof, and more particularly to an image forming method and an image processing method and an apparatus thereof for preventing forgery of an image original.

[0002]

2. Description of the Related Art Conventionally, in order to prevent forgery of banknotes, securities, etc., a specific image of banknotes, securities, etc. is preprinted / printed with a pattern that cannot be resolved / copied by a color copier, etc. An image pattern in the density range, which has poor reproducibility on a copying machine, is printed in advance, metal is adhered to the paper so that the authenticity of the image can be easily discerned by the metallic luster, or a fluorescent substance is used. Various measures are taken, such as printing / printing images and including fibers dyed with a fluorescent substance in the paper when manufacturing the paper.

In addition, it has been on the market since 1993,
For example, a digital electrophotographic full-color copying machine such as CLC550 / CLC350 manufactured by Canon Inc. is equipped with a banknote pattern recognition function, and if the copying machine determines that the original is a banknote, it is forced to have a different color. Counterfeiting is prevented by forming a copy.

[0004]

However, with the widespread use of full-color copying machines in recent years, anyone can easily use devices such as full-color copying machines.
Therefore, even if the anti-counterfeiting technique as in the conventional example is incorporated in the color copying machine from the printing stage of the specific image, the person who does not know that such technique is used is not known. However, knowing that a full-color copying machine can produce a copy having substantially the same visual image, there is a possibility that it may be easily involved in illegal forgery.

Therefore, there is a demand for means for preventing such illegal acts themselves. Furthermore, even in full-color copying machines with anti-counterfeiting functions, anti-counterfeiting is applicable only to commonly distributed banknotes, etc. The current situation is that the specific image has not been discriminated. Of course, forgery may be theoretically prevented by storing various types of image data to be discriminated inside the copying machine and performing pattern matching using these image data. However, for that purpose, a large-capacity memory is required to store an enormous amount of image data, and a very long processing time is required for pattern matching using these data. Such a method is not realistic in view of the original copy performance.

Accordingly, there is a need for a forgery prevention technique for a wider range of specific images that can be applied in a simpler, more economical and realistic way. The present invention has been made in view of the above conventional example, and provides an image forming method, an image processing method, and an apparatus thereof capable of preventing counterfeiting of a wide variety of images by a simpler and more economical method. Is intended.

[0007]

In order to achieve the above object, the image processing method of the present invention comprises the following steps. That is, the image original printed by using the first recording material having the peak of the spectral reflection characteristic in the first wavelength band is
A reading step of optically reading using a reading device having a low light receiving sensitivity to light in the wavelength band of, and an image forming step of forming an image on a recording medium based on the image signal read in the reading step. An image processing method having the above is provided.

According to another aspect of the invention, an image original printed using a first recording material having a spectral reflection characteristic peak in the first wavelength band is optically read, and in the first wavelength band. The image processing apparatus includes a reading unit having a low light receiving sensitivity to the light and an image forming unit that forms an image on a recording medium based on the image signal read by the reading unit.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The first aspect of the present invention has the above-mentioned structure.
The image original printed using the first recording agent having a spectral reflection characteristic peak in the wavelength band of is optically read using a reading device having low light receiving sensitivity to light in the first wavelength band, It operates to form an image on a recording medium based on the read image signal.

Here, the first recording material contains an ink whose spectral reflection characteristic has a peak at a wavelength of 500 ± 25 nm. Further, the reading device may read an image original printed using the first recording material and the second recording material having the peak of the spectral reflection characteristic in the second wavelength band. Here, the second
The recording material has a spectral reflection characteristic of wavelength 600 ± 25 nm.
Includes ink with a peak at.

Further, the reading device comprises a first recording material,
An image original printed using the mixed recording material of the first recording material and the third recording material having no peak of the spectral reflection characteristic may be read. Here, the third recording agent is mixed so that the first recording agent and the third recording agent visually appear to have substantially the same color. Now, in the reading device, a light source for irradiating the image original with light, and a light receiving / separating means including three color filters for receiving the reflected light emitted from the light source and reflected by the image original, and separating the light into three RGB components And photoelectric conversion means such as a CCD for converting the three-component light received and decomposed by the light reception and decomposition means into an electric signal. Here, each of these three color filters has a spectral characteristic that maximizes sensitivity to light having wavelengths of 450 nm, 550 nm, and 650 nm. And these three
The light transmittance of the combination of two color filters is
It has a spectral characteristic that the wavelength becomes low near 500 nm and near 600 nm.

The above-mentioned image formation can be carried out according to an electrophotographic method. For the image formation, a light emitting means for driving a semiconductor laser by a signal pulse-modulated according to an image signal to emit a beam of light, The latent image forming means for forming an electrostatic latent image by scanning the photoconductor with the light beam and the latent image formed on the photoconductor are formed by using black toner, yellow toner, magenta toner, and cyan toner. A developing means for developing a color image is used. Here, the reflectance due to the combination of the black, yellow, magenta, and cyan toners has a spectral characteristic that becomes lower near the wavelength of 500 nm and near 600 nm.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a spectrum showing a spectral reflection characteristic of an ink used for printing a specific image such as a bill, a securities, a gift certificate, and a lottery ticket as one embodiment according to the present invention. According to FIG. 1, this ink has a wavelength near 500 nm (for example, 500 ± 25 n).
It has a characteristic of having a sharp reflectance with respect to the light of m).

FIG. 2 shows a digital full-color copying machine 100 (hereinafter referred to as a copying machine) which forms an image according to an electrophotographic system based on various image originals including printed matter printed with ink having the characteristics shown in FIG. Is a side sectional view showing the configuration of (). As shown in FIG. 2, the copying machine 100 includes a reader unit A that reads an image original and generates an image signal, and a printer unit B that forms an image based on the image signal.

In FIG. 2, when the original 192 on the original table glass 193 is illuminated by the light source 190, the reflected light is input to the CCD 21 via the optical lens 104, and CC
At D21, it is converted into an electric image signal according to the amount of received light.
The light source 190, the optical lens 104, and the CCD 21 constitute the image reading unit 101, and the image reading unit 101
Is moved in the direction of arrow a shown in FIG. 1, the entire surface of the image original is scanned and the image is read.

FIG. 3 is an external perspective view showing the structure of the CCD 21. As shown in FIG. 3, the CCD 21 is arranged in three lines in a direction perpendicular to the drawing sheet of FIG. 2, and R (red), G (green), and B (blue) color separation filters 22R and 22G are arranged for each line. , 22B are installed in front of the CCD light receiving element. Therefore, the light hν incident on the CCD 21 is converted into image signals of RGB components.

FIG. 4 shows color separation filters 22R, 22G and 2
It is a spectrum which shows the spectral transmittance characteristic of 2B. It is well known that silver salt photographic development, full-color image reproduction by a color television, and color image formation by a copying machine used in this embodiment are basically established by the principle of three primary colors. . Therefore, as shown in FIG.
The spectral transmittance characteristics of the color separation filters 22R, 22G, and 22B are basically different, although there are some differences depending on the use of the color separation filter such as silver halide photographic development, color image display on a color television, and color printing. Is 400 nm to 500 nm and 500 nm to 6 in each of RGB.
In the wavelength region of 00 nm, 600 nm to 700 nm,
Almost all have peak characteristics in the vicinity of 450 nm, 550 nm, and 650 nm.

Now, returning to FIG. 2 and continuing the explanation, CC
The output of D21 is digitally converted by the A / D converter 22, and the digital image data is converted into the signal processing circuit 10.
Sent to 5. The image signal processed by the signal processing circuit 105 is PWM-modulated, converted into a drive signal for driving the semiconductor laser 103, and output to the laser driver 102. The laser driver 102 is a circuit for driving the semiconductor laser 103, and controls ON / OFF of light emission of the semiconductor laser 103 according to an input drive signal.

Laser light emitted from the semiconductor laser 103 is swung by the polygon mirror 105 in the direction perpendicular to the paper surface of FIG. 2, scans on the photosensitive drum 106 via the mirror 2, and an electrostatic latent image is formed on the photosensitive surface. Form an image. The photosensitive drum 106 on which the latent image is formed by the scanning of the laser light is
It rotates in the direction of the arrow shown in the figure. By this rotation, Y
Four developing units (indicated by Y, M, C, and K in the figure) that develop the latent image using toners of (yellow), M (magenta), C (cyan), and Bk (black), respectively. Development is performed for each color by the developing device 112 provided with.

On the other hand, the recording paper 6 is fed from a recording paper cassette (not shown), is wound around the transfer drum 113, and is rotated once every Y (yellow), M (magenta), C (cyan), Developing device 1 in the order of Bk (black)
The image developed by 12 is transferred, and the toner image of four colors is multi-transferred by rotating four times in total, and the color recording is completed. When the color transfer is completed in this way, the recording paper is separated from the transfer drum 113 and the fixing roller pair 11 is released.
The image is fixed by 4, and the color image print is completed.

In FIG. 2, 8 is a photosensitive drum 10.
A charger for charging 6 to an equipotential, and a charge eliminator 9 for removing residual potential. FIG. 5 is a block diagram showing the configuration of the signal processing circuit 105. The RGB digital image signal obtained by the conversion by the A / D conversion circuit 22 is subjected to shading correction by the shading circuit 23, and further, LO
The G conversion circuit 24 converts CMY from RGB luminance signals.
Converted to a density signal. As for the CMY density signal, a Bk generation circuit + masking processing circuit 122 generates a black component (K) signal and a YMCK4 component density signal. The YMCK density signal is subjected to gradation conversion by a γ-LUT (look-up table) 25 in consideration of the color expression characteristics of the printer, and then the pulse width conversion circuit 2
PWM modulation is performed at 6 to generate a drive signal for driving the semiconductor laser 103. Then, based on the drive signal, the laser driver 102 drives the semiconductor laser 103 to form an image.

FIG. 6 is a spectrum showing spectral characteristics of yellow (Y), magenta (M), cyan (C), and black (K) toners used by the printer section B of the copying machine 100. Now, the color separation filters 22R and 22G shown in FIG.
Considering the combination of the fact that the reading ability for single wavelength light around 500 nm and 600 nm is poor due to the spectral characteristics of 22B and the spectral reflectance characteristics of the toner as shown in FIG. Colors with peaks cannot be expressed in principle. Therefore, although the colors cannot be said to be the same spectrally, color conversion is performed on the chromaticity coordinates in the Lab space or the like to find colors that are equal in color in that space.

However, for example, when a printed matter printed with an ink having a spectral reflection characteristic as shown in FIG. 1 is copied, the printed matter has the sharpest reflection in the vicinity of the wavelength where the color reproducibility is the worst for the copying machine 100. Because of its characteristics, the tint of the copy changes as compared with that of the printed document. FIG. 7 is a diagram showing an example of an image original copied by the copying machine 100. The shaded area A of the image original shown in FIG. 7 is printed using the ink having the spectral characteristics shown in FIG.

FIG. 8 is a spectrum showing a spectral reflection characteristic of a region of the copy obtained by copying the image original shown in FIG. 7 with the copying machine 100, which corresponds to the shaded area A in FIG. . As is clear from comparison between FIG. 8 and FIG. 1, due to the color reproduction characteristics of the device, the shapes of the two vector vectors are considerably different, especially near the wavelength of 500 nm (500 ± 25 nm), and the color of the image original is The taste and the tint of the color reproduced in the copy are completely different. This becomes clearer when comparing the tint of the image original with that of the copy using the ab chromaticity coordinate system in the Lab space.

FIG. 9 shows the ab chromaticity coordinate system in the Lab space.
It is a figure which compares the color of an image original with the reproduced color of a copy.
According to FIG. 9, the original color, which was bluish green, is reproduced in a completely different color from the reproduction color to a slightly bluish gray. Therefore, according to the embodiment described above, the spectral characteristics of the image reading unit and the printer unit of the copying machine are taken into consideration, and the wavelength band with the worst color reproducibility of the apparatus,
By using an ink having a sharp peak of reflectance for printing an image original, the tint of the reproduced color of the copy of the image original can be changed, so that the image original can be reproduced without complicating the apparatus configuration. Forgery can be easily prevented regardless of type.

Further, according to this embodiment, since the tint of the copy itself is different from that of the original, it is possible to conclude that the person who attempts the forgery cannot forge even using this device. Because it can, it will contribute to the prevention of counterfeiting itself.

[0027]

[Other Embodiments] In the above example, the anti-counterfeiting is achieved by using only one kind of ink having a special spectral reflection characteristic. However, the functions provided in the recent digital electrophotographic full-color copying machine are Considering this, it is possible to prevent forgery by using a plurality of inks having special spectral reflection characteristics.

That is, a recent color copying machine is provided with a mechanism capable of changing the gradation characteristic of the printer for each YMCK density component and adjusting the color according to the preference of the user. Therefore, in the case of an original of a printed matter printed by using only one kind of ink having a special spectral reflection characteristic, it is possible to reproduce the same color tone as the original color in the duplicate by the color adjusting mechanism.

Considering the case where such a device is used, for example, the spectral reflection characteristics shown in FIG.
An image original as shown in FIG. 11 is printed using the types of ink d and ink e. In FIG. 11, the area D prints an image by using the ink d shown in FIG. 10 and the area E uses the ink e shown in FIG. When the image original printed in this way is copied by the copying machine 100, the spectral reflection characteristics corresponding to the respective shaded areas D and E in FIG. 11 of the obtained copy are D ′ shown in FIG. It becomes a spectrum like E '. As is clear from comparison between FIG. 12 and FIG. 10, due to the color reproduction characteristics of the device, the shape of the scan vector shown in each of the figures is particularly 500 nm and 600 nm.
In the vicinity of 500 nm (500 ± 25 nm, 600 ± 25 nm), there is a considerable difference, and the tint of the image original and the tint of the color reproduced in the copy are completely different. This becomes clearer when comparing the tint of the image original with that of the copy using the ab chromaticity coordinate system in the Lab space.

FIG. 13 is a diagram comparing the color of the image original with the reproduced color of the copy in the ab chromaticity coordinate system of the Lab space. As shown in this figure, the colors of the inks d and e used in the image original are reproduced in different colors. Therefore, images are printed using multiple inks with special spectral reflection characteristics that take into account the color reproduction characteristics of the device.
Even if you try to adjust the color using the color adjustment mechanism of the device when copying the printed matter, it is possible to adjust the color characteristics of multiple inks to match the color and reproduce the same color as the image original. It will be more difficult.

This makes it possible to prevent counterfeiting using a copying machine having a color adjusting mechanism. Further, in the above-described embodiment, an example in which a specific image is printed by using a plurality of (two types) inks having special spectral reflection characteristics has been described, but one of the inks is usually used for printing. A standard ink called a process ink may be used.

FIG. 14 is a spectrum showing the spectral reflection characteristics of the ink e and the process ink f. As can be seen by comparing FIG. 14 and FIG. 6, the process ink f has a spectral reflection characteristic similar to that of magenta toner used in electrophotographic image formation, and has a wavelength of 5
There is no peak near 00 nm and 600 nm.
The spectral characteristics of the two inks are different from each other. Therefore, in principle, the copying machine 100 cannot form an image with a tint having a spectral reflection characteristic like the ink e. Further, as can be seen from such spectral characteristics, when the ink e and the process ink f are mixed, it is possible to print in a color that visually looks like the same color as the process ink f.

FIG. 15 shows a region E "(a region expressing the character" invalid ") printed with a mixed ink of the ink e and the process ink f, and a region F" (a region expressing the character "invalid"). It is a figure which shows the image containing the (background of a hatched part). When this image is printed, if it is printed with a slight overlap so that the boundary between the character and the background cannot be seen, the character "invalid" cannot be visually identified.

When the image original printed in this way is copied by the copying machine 100, only the ink e is reproduced with a different tint, while the process ink f is reproduced in the reproduced color (x) as shown in FIG. Is reproduced well enough to show almost no difference from the color tone (○) of the image original. as a result,
Only the character "Invalid" is reproduced with a different color and the character becomes legible. As a result, at a glance of the copy, it becomes possible to easily determine whether or not the copy is a forged one. In this way, when printing a specific image, an ink having a special spectral characteristic that is difficult to reproduce with a copying machine and a process ink used in normal printing are combined or mixed to form a specific pattern for the human eye. It is possible to prevent counterfeiting by printing so that it is difficult to discriminate, and at the time of copying, an image is formed so that a specific pattern that is difficult for the human eye to discern is visualized.

Furthermore, it is also possible to use an apparatus having a structure in which a developing device for developing using toner having a specific spectral characteristic is added. FIG. 17 shows the copying machine 10 shown in FIG.
FIG. 2 is a side sectional view showing the configuration of a copying machine in which a developing device 170 is added to 0. In FIG. 17, reference numeral 170 is provided below the developing device for developing with magenta toner in the developing device 112, and is the same color as the cyan toner used in the developing device 112, but peaks in the wavelength band of 600 ± 25 nm. It is a developing device that performs development using a toner having a spectral characteristic with. The other components are the same as those shown in FIG. 2, and therefore, the same device reference numerals are assigned here and the description thereof is omitted.

FIG. 18 is a block diagram showing the structure of the signal processing circuit 195 shown in FIG. According to this configuration, the Bk generation circuit + masking processing circuit 122 and γ−
An image synthesizing circuit 181 is provided between the LUT (look-up table) 25 and the image synthesizing circuit 181, and the image signal from the pattern generator (PG) circuit 182 is converted into Bk.
It is superimposed on the output signal from the generation circuit + masking processing circuit 122.

FIG. 19 shows a pattern generator (PG).
It is a figure which shows the example of the image for the superposition which the circuit 182 produces. According to this example, an "invalid" pattern image is generated. When forming an image using this pattern, "h toner (toner used in the developing device 170)" is used for the pattern image "invalid", and "g toner (developing device 112 of the developing device 112) is used in the peripheral portion of the pattern. Processing using the toner used in the developing device for the cyan image).
In the actual image forming process, such pattern superimposition is performed uniformly over the entire formed image area,
Further, it is desirable to form at a specific gradation level (for example, 40 out of 256 gradations) so as not to disturb the original formed image.

FIG. 20 is a diagram showing spectral characteristic spectra of "h toner" and "g toner". With the above-described configuration, the full-color image and the pattern image to be superimposed on the full-color image are formed by performing the multiple transfer process five times. In addition, in the case of such a configuration, even in the case of a normal copy, 1
The number of extra image development and transfer processes increases and the image formation time becomes longer. Therefore, only when the copy operation is performed in the mode in which a pattern is added to prevent forgery by an instruction from the operation panel, etc. You may make it add a pattern like this. Further, in the above example, the case where the pattern addition is performed with the cyan toner has been described, but it goes without saying that the pattern addition may be performed with the yellow or magenta toner.

In the above embodiment, the digital full-color copying machine according to the electrophotographic system is used, but the present invention is not limited to this. When an image original is read, an image signal composed of color components of RGB three luminances is generated, and if a full-color image formation is formed based on the image signal, another image forming system device may be used. Needless to say, the present invention can also be applied.

The present invention may be applied to a system composed of a plurality of devices (for example, host computer, interface device, reader, printer, etc.), or an apparatus composed of one device (for example, a copying machine). , Facsimile machines, etc.).

[0041]

As described above, according to the present invention, the image original printed using the first recording material having the peak of the spectral reflection characteristic in the first wavelength band is printed in the first wavelength band. Is read optically using a reading device with low light-receiving sensitivity, and an image is formed on the recording medium based on the read image signal, so the colors reproduced in the image formed on the recording medium There is an effect that the taste becomes different from that of the image original.

Therefore, by taking into consideration the spectral characteristic of the recording material used for printing the image original and the spectral characteristic of the image processing apparatus, the image of any kind of specific image original can be obtained with a simple structure. The tint can be changed during reproduction and reproduction of, and forgery can be prevented. Further, according to the present invention, since a complicated structure is not required, there is also an advantage that a device capable of preventing forgery can be provided at a lower cost.

[Brief description of drawings]

FIG. 1 is a spectrum showing a spectral reflection characteristic of an ink used for printing a specific image as one embodiment according to the present invention.

FIG. 2 is a side sectional view showing the configuration of a digital full-color copying machine 100 that forms an image of an image original according to an electrophotographic system, including a printed matter printed with an ink having the characteristics shown in FIG.

FIG. 3 is an external perspective view showing a configuration of a CCD 21.

FIG. 4 is a spectral spectrum showing spectral transmittance characteristics of color separation filters 22R, 22G, and 22B.

5 is a block diagram showing a configuration of a signal processing circuit 105. FIG.

FIG. 6 is a spectrum showing spectral characteristics of yellow (Y), magenta (M), cyan (C), and black (K) toners used by the printer unit B of the copying machine 100.

7 is a diagram showing an example of an image original copied by the copying machine 100. FIG.

8 is a spectrum showing a spectral reflection characteristic of a region of a copy obtained by copying the image original shown in FIG. 7 with a copying machine 100, which corresponds to a shaded area A in FIG.

FIG. 9 is a diagram comparing a color of an image original with a reproduced color of a copy in an ab chromaticity coordinate system in a Lab space.

FIG. 10 is a spectrum showing spectral reflection characteristics of two kinds of ink d and ink e.

FIG. 11 is a diagram showing an image original printed using two kinds of ink d and ink e.

12 is a spectrum showing spectral reflection characteristics of regions corresponding to regions D and E in FIG. 11 of a copy obtained by copying the image original shown in FIG. 11 with a copying machine 100.

FIG. 13 is a diagram for comparing the color of the image original and the reproduced color of the copy in the ab chromaticity coordinate system of the Lab space.

FIG. 14 is a spectrum showing the spectral reflection characteristics of ink e and process ink f.

FIG. 15 is a diagram showing an image including a region E ″ printed with a mixed ink of ink e and a process ink f, and a region F printed with a process ink f.

FIG. 16 is a diagram for comparing a color of an image original and a reproduced color of a copy in an ab chromaticity coordinate system of Lab space.

17 is a side sectional view showing the configuration of a copying machine in which a developing device 170 is added to the copying machine 100 shown in FIG.

18 is a block diagram showing a configuration of a signal processing circuit 195 shown in FIG.

FIG. 19 is a diagram showing an example of an image generated by a pattern generator (PG) circuit 182 for superimposition.

FIG. 20 is a diagram showing spectral characteristic spectra of “h toner” and “g toner”.

[Explanation of symbols]

 21 CCD 22 A / D converter 23 Shading circuit 24 LOG conversion circuit 25 γ-LUT 26 Pulse width conversion circuit 102 Laser driver 103 Semiconductor laser 104 Optical lens 105 Polygon mirror 106 Photosensitive drum 112 Developer 113 Transfer drum 114 Fixing roller pair 122 Bk generation circuit 190 Light source 192 Original 193 Original platen glass 195 Signal processing circuit

Claims (17)

[Claims] 1. An image original printed by using a first recording material having a peak of spectral reflection characteristics in a first wavelength band is optically read, and the light receiving sensitivity of light in the first wavelength band is measured. An image processing apparatus having a low reading unit and an image forming unit that forms an image on a recording medium based on an image signal read by the reading unit. 2. The image processing apparatus according to claim 1, wherein the first recording material includes ink having the spectral reflection characteristic having a peak at a wavelength of 500 ± 25 nm. 3. The reading means reads an image original printed by using the first recording material and the second recording material having a peak of spectral reflection characteristics in a second wavelength band. The image processing device according to claim 1. 4. The image processing apparatus according to claim 3, wherein the second recording material contains ink having the spectral reflection characteristic having a peak at a wavelength of 600 ± 25 nm. 5. The reading means is printed using the first recording agent and a mixed recording agent of the first recording agent and a third recording agent having no peak of spectral reflection characteristics. The image processing apparatus according to claim 1, wherein the image processing apparatus reads an image original. 6. The image processing apparatus according to claim 5, wherein the first recording agent and the third recording agent visually appear to have substantially the same color. 7. The reading means includes a light source for irradiating the image original with light, and a light receiving and decomposing means for receiving reflected light emitted from the light source and reflected by the image original, and for decomposing it into RGB three components. The image processing apparatus according to claim 1, further comprising a photoelectric conversion unit that converts the light of the three components received and decomposed by the light reception and decomposition unit into an electric signal. 8. The light receiving / separating means includes three color filters corresponding to the three components, and each of the three color filters has a wavelength of approximately 450 n.
The image processing apparatus according to claim 7, wherein the image processing apparatus has a spectral characteristic that maximizes sensitivity to light of m, 550 nm, and 650 nm. 9. The light transmittance of the combination of the three color filters has a wavelength near 500 nm, and
The image processing apparatus according to claim 8, having a spectral characteristic that becomes low in the vicinity of 600 nm. 10. The image processing apparatus according to claim 1, wherein the image forming unit forms an image according to an electrophotographic method. 11. The image forming means drives a semiconductor laser by a signal pulse-modulated according to the image signal to emit a beam of light, and the beam of light scans a photoconductor to form an electrostatic latent image. A latent image forming unit for forming a latent image formed on the photosensitive member; and a developing unit for developing a color image by using a black toner, a yellow toner, a magenta toner, and a cyan toner for the latent image formed on the photoreceptor. The image processing apparatus according to claim 10. 12. The reflectance of the combination of the black, yellow, magenta, and cyan toners has a spectral characteristic that becomes lower near a wavelength of 500 nm and near a wavelength of 600 nm. The image processing apparatus according to claim 11. 13. A reading device having a low light-receiving sensitivity to an image original printed using a first recording material having a peak of spectral reflection characteristics in a first wavelength band is low in light receiving sensitivity to light in the first wavelength band. An image processing method comprising: a reading step of optically reading by using the image reading step; and an image forming step of forming an image on a recording medium based on the image signal read in the reading step. 14. The reading step reads an image original printed using the first recording material and a second recording material having a peak of spectral reflection characteristics in a second wavelength band. The image processing method according to claim 13. 15. The reading step is performed using the first recording material and a mixed recording material of the first recording material and a third recording material having no peak of spectral reflection characteristics. 14. The image processing method according to claim 13, further comprising reading the image original. 16. A spectral reflection characteristic of 500 on a recording medium.
600 ± 25 with the first recording agent with a peak at ± 25 nm
An image forming method, wherein an image is formed using at least one of the second recording agents having a peak at nm. 17. The image forming method according to claim 16, wherein an image pattern is formed on the recording medium by combining at least one or more process inks that are visually equal in color.