JPS6152654A - Multicolor image forming method - Google Patents

Abstract

PURPOSE:To prevent image information from being disordered even if a generation copy is repeated by constituting a device so that an original image of an intermediate color of the original image of at least two colors can be reproduced by a specified color prescribed in advance. CONSTITUTION:An original 13 on which a multicolor image has been formed is placed on a contact glass 12, and illuminated and scanned by a light source 15. Its reflected light is reflected by scanning mirrors 16, 17 in the same way, and passes through a half mirror 21 and an image forming lens 19. In this case, one of filters 20R, 20B and 20G of red, blue and green of a filter device 20, for instance, the filter 20R is brought into an optical path, and a light which has transmitted through said filter is reflected by a mirror 18, executes an image exposure to a photosensitive body 1, and forms an optical image of an optical component which has passed through the filter 20R. Subsequently, in accordance with necessary, the correcting exposure is executed, thereafter, when passing through a cyan developing device 7, said image is converted to a toner image by a cyan toner CT being in a complementary color relation to the filter 20R. Subsequently, the filters 20B, 20G are used, the image is converted to a toner image by toners YT, MT, and overlapped and transferred on the same transfer material 25.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses at least two types of color separation filters,
A multicolor image forming method in which a photoreceptor is imagewise exposed to light from an original that has passed through each filter to form an electrostatic latent image, and the latent image is developed with toner of a color complementary to that of the filter used for image exposure. Regarding.

The method of forming a multicolor image of the type described above is well known in the art. When obtaining a copy image using this type of method, the following points are usually required in general business.

■ The image information of the original must be accurately reproduced.

■ Document information is not lost even when so-called generation copying, in which a copied image is copied as a document, is repeated.

For example, when copying a multicolor image created by a color printer for an office computer as an original, if the original information cannot be accurately reproduced, not only will the meaning of the copy be lost, but it may also lead to unexpected problems. In a normal multicolor copying machine, the characteristics of the photoreceptor and other image forming elements are affected by external factors such as temperature and humidity.

Since some 0 changes due to deterioration over time, it is more difficult to always reproduce the color of the original image in a constant color, and in some cases it may not be possible to accurately reproduce the image information of the original, especially when generating copies. As the number of times increases, the tendency force increases by 1.

- For example, if the output information created by a color printer is formed by a red image and a yellow image,
If you repeat the operation of copying this image information as a manuscript and then copying the copied image as a manuscript, as the number of repetitions increases, the red and yellow images will deviate from their original colors, and these will become orange or tangerine. The color changes to an intermediate color, and finally reaches a state where the image information cannot be identified.

Also, even if the information is the same, the colors may differ slightly depending on the printer model or manufacturer.
For example, information that is displayed in orange on the printer of company A may be displayed in orange, which is closer to yellow, in the printer of 8 companies, and in sunflower color, which is even closer to yellow, in the printer of company 0. In such a case, when copying, especially generation copying, a document having such intermediate color image information and red or yellow image information, information confusion will occur particularly significantly.

1. The present invention has been made based on the above recognition, and its purpose is to form a multicolor image in which confusion of image information or deterioration of distinguishability does not occur as in the past even if generation copying is repeated. The purpose is to provide a method.

In order to achieve the above-mentioned object, the present invention provides a method for at least one exposure of a photoreceptor so that a document image of an intermediate color between at least two color document images is reproduced in a predetermined specific color. , or before or after that, a configuration is proposed in which a latent image or a photoreceptor portion corresponding to the intermediate color image portion is subjected to corrective exposure using an erase device. With this configuration, although it may not always be possible to form a multicolor image that is faithful to the original image, the image information itself can be accurately reproduced, and the confusion of information that accompanies repeated generation copying required for normal business operations. It is possible to prevent this.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of a copying machine that implements the method according to the present invention. First, its overall configuration and basic operating mode will be explained.

In FIG. 1, an original 13 on which a multicolor image is formed is placed on a contact glass 12 provided at the top of the copying machine main body, and this original is illuminated by a scanning light source 15 placed below the original. Illumination is scanned. The reflected light is reflected by a mirror 16 that similarly scans and another mirror 17, and is then reflected by a half mirror 21 and an imaging lens 1, which will be described later.
Pass through 9.

At this time, one of the red, blue, and green filters 20R, 20B, and 20G of the filter device 20, for example, the red filter 2OR, is brought into the optical path, and the light from the document that has passed through this filter 2OR is transmitted to the mirror 18.
The photoreceptor 1 is exposed to the image, and the filter 2O is applied here.
A light image of the light component that has passed through R is formed.

The illustrated photoreceptor 1 is formed into a drum shape, and has a conductive drum base having panchromatic spectral sensitivity.
A material on which s 2 S e 3 is vapor-deposited is used. The photoreceptor 1 is rotationally driven in the counterclockwise direction in the figure.
It is uniformly charged in advance to a predetermined polarity, for example, +100 OV, by the charger 2, so that an electrostatic latent image is formed on the photoreceptor 1 by the image exposure.

The latent image is subjected to corrective exposure as necessary as described later, and then, when passing through the cyan developing device 7, it is converted into a toner image by cyan toner CT having a complementary color relationship with the red filter 2OR.

The cyan toner image is transferred by a transfer charger 9 to a transfer material 25 wrapped around a transfer drum 8 rotating clockwise, and the photoreceptor 1 after transfer is transferred to a charger 1.
0, the remaining toner is removed by the cleaning device 11.

A second copying operation is performed following the first copying operation described above. During this operation, the blue filter 20B of the filter device 20 is brought into the optical path, and the latent image formed thereby passes through the yellow developing device 5. When passing through, a toner image is formed by yellow toner YT, which has a complementary color relationship with the blue filter, and this is transferred onto the previously described transfer material 25 from above the cyan toner image.

Next, in the third operation, a green filter 20G is used, and when the latent image formed by the light passing through it passes through the magenta developing device 6, it is converted into a toner image by magenta toner MT, which is a complementary color to the green filter 20G. The images are transferred onto the same transfer material 25 in an overlapping manner.

As described above, a multicolor image is formed on the transfer material 25,
This image appears after the transfer material 25 is removed from the transfer drum 8.
The image is fixed by the fixing device 27.

The order of the filters 2OR, 20B, and 20G used may be arbitrary.

Among the above-mentioned basic configurations and their functions, there is no difference from conventional multicolor copying machines except for the correction exposure and the configuration of the half mirror related thereto. Next, color correction will be explained in detail.

Now, to simplify the explanation, as shown in Figure 3 (a),
Assume that a red image R1, an orange image S, a tangerine image T that is closer to yellow, a sunflower image U that is even closer to yellow, and a yellow image Y are formed on the document 13. In this case, in this example, it is assumed that the image information written on the original 13 is originally expressed in red and yellow, and this original 13 has changed from its original color as a result of repeated generation copying with a conventional multicolor copying machine. 1 It is assumed that an image that was originally red has changed to an orange image, and similarly an image that was originally yellow has changed to an image of orange and sunflower colors, and even if the original color has changed in this way, the present invention It will be revealed that it is possible to restore the original color by copying using the method described above.

As described above with reference to FIG. 1, when the original 13 is illuminated by the light source 15, the reflected light is reflected by
1, but the split light that is reflected without passing through this passes through the imaging lens 22 and reaches the color scanner 23, where a document image is formed. As the color scanner, any suitable scanner known per se can be used. How<C0D
Red R' and green G' superimposed on each of the 26 light receiving sections
, Blue B', and these filters are arranged alternately in the above order.

When light from the original reaches these filters, the light passes through depending on its properties, and the C0D2 for the three types of filters
By comparing the three types of signals from 6, the color of the original image can be determined in minute units, and in this example, two colors, red and yellow, are determined. This judgment operation occurs during the first exposure of the photoreceptor.

That is, the process may be performed only when the red filter 2OR is used, and the result may be stored, or it may be performed each time the photoreceptor is exposed to an image.

On the other hand, when viewed in the rotational direction of the photoconductor 1, there is a region between the charger 2 and the developing device, in this example, a region downstream of the exposure section.
Light emitting diode array (hereinafter referred to as LED array) 3
An erase device consisting of is placed opposite to the photoreceptor 1, and this LE
The D array 3 is arranged in a direction perpendicular to the paper plane of FIG.
It has a large number of light emitting parts facing the photoreceptor 1.

As described above, the light passing through the filters 20R, 20B, or 20G exposes the photoreceptor 1 to form a latent image, but when the blue filter 20B is used, the light from the original shown in FIG. 3(a) , a latent image is formed as shown in the same figure. That is, original images R and S.

The reflected light from T, U, and Y contains blue component light (40
0 to 500 nm) is hardly included.
Almost no light is applied to the surface of the photoreceptor corresponding to these g-stripe images, and if the reduction due to natural attenuation is ignored, the surface potential is no different from the potential immediately after the IF charge by the charger 2. Stillness corresponding to each image? ! ! Latent images R1, SL, Tl, Ul.

Yl is formed. These latent images pass under the LED array 3 as the photoreceptor 1 rotates, but the latent image shown in FIG. 3(a) is not erased as will be explained later; The latent image was explained earlier and is shown in Figure 3(b).
), the yellow toner YT forms a toner image, and this toner image is transferred to the transfer material 25 as shown in FIG. 3(c).

Next, as shown in FIG. 3(d), the photoreceptor 1 is image-exposed by exposing the photoreceptor 1 to light from the document 13 that has passed through the green filter 20G. At this time, the state of formation of the latent image is as follows. The result is as shown in the lower part of FIG. 3(d). That is, green component light (500 to 60
The surface potential of each latent image corresponding to these is determined by the amount of 0 nm). In this example, as shown in the Vs(1) column of Table 1, the red latent image R1 of the red image R is +1ooov
(?+F), the orange latent image S1 of the orange image S is +
700 V, orange latent image T1 of orange color image T is +50
0v, sunflower latent image U1 of sunflower image U is +300v
Assume that since the reflected light from the yellow image Y contains a large amount of green component light, the surface potential of the photoreceptor portion corresponding to this image is OV. Note that the numerical values in the column of composition in Table 1 indicate the composition ratio of yellow Y and magenta M coloring materials (toner in this case) constituting each original image.

On the other hand, the color of the original image is determined by the color scanner 26.
It is a quiet indication. That is, when light from each original image R, S, T, U, and Y enters each set of three types of filters R', G', and B' in the scanner 2G, these lights contain red component light. 600 to 700 nm), the CCD corresponding to the red filter R' outputs "1", and conversely, the output from the CCD corresponding to the blue filter B' becomes "0". , the output of the COD corresponding to the green filter G' is determined by the amount of green component light incident on them as shown in Table 1.
0 each. , 0.3.0.5.0.7.1 (however, these output values are relatively standardized values),
In this way, the color of the document portion that is incident on one set of three types of filters can be determined based on the difference in the COD output values corresponding to each set of filters R' and G'3 / , and the determination results in this example are shown in Table 1. This is as shown in the column of Judgment (1).

When the latent image shown in FIG. 3(d) reaches the bottom of the LED array 3, the latent image corresponding to the original image in which the output of the CCD corresponding to the above-mentioned green filter G' is in the range of 1 to 0.5 is , is erased by selectively emitting light from each light emitting section of the LED array 3 according to a preset program. That is,
As shown in the erase (1) column of Table 1 and FIG. 3(e), when the photoreceptor portion yt corresponding to the tangerine latent image T1, the sunflower latent image U1, and the yellow image passes under the LED array, The light emitting part turns on (lights up), corrects these with light, reduces the surface potential to a value to which toner cannot adhere, for example, approximately Ov, and the red latent image R1 and orange latent image S1 become L
When passing under the ED array, its light emitting part is turned off (extinguished) and its surface potential is maintained. Since the original surface potential of the photoreceptor portion Y1 is approximately ov, light may not be applied to this portion. This is an erase operation. The surface potential of each latent image after passing through the LED array 3 in this manner becomes as shown in the Vs' (1) column of Table 1, leaving a red latent image R1 and an orange latent image S1. In this case, the surface potential (Ov) of the photoconductor portion from which the latent image has been erased and the surface potential (700 to 1ooo, v) of the remaining latent image are larger than each other (
The surface potentials of the two are clearly separated. These latent images R1, Sl are converted into toner images by magenta toner MT as shown in FIG. 3(f), but the latent images R1, S1 are
There is a clear difference in surface potential between L and the other molecules l, Ul, and Yl, and therefore, a large amount of toner image up to a saturated state is surely attached to the former, and no toner is attached to the latter. This magenta toner image is superimposed and transferred onto the transfer material 25 to which the ink rotor toner image has already been transferred (FIG. 3(g)).
Then, it is fixed (FIG. 3(h)).

Looking at the multicolor image completed as described above, the red image R and orange image S of the original are reproduced as a red image R2, and the orange image T, sunflower image U, and yellow image Y are reproduced as a yellow image. It is reproduced in image Y2, which is M draft 1
3 corresponds to the image that should be displayed as the original information. Furthermore, even if a generation copy is performed in which the multicolor image shown in Fig. 3(h) is copied as a manuscript, and the resulting multicolor image is further copied as a manuscript, each time the multicolor image shown in Fig. 3(h) is A similar multicolor image is obtained.

During each copying operation, the surface potentials of the photoreceptor molecules I, Ul, and Yl to which toner (magenta in the above example) should not be attached are lowered by corrective exposure, and the latent images R1 and SL to which toner should be attached to a saturated state are lowered. This is because the difference between the surface potential of the toner and the surface potential of the toner is made clear, and unstable development in which toner adheres or does not adhere due to changes in external factors is eliminated.

The method described above limits the number of colors in the multicolor image that can be obtained;
In the example above, orange, tangerine, and sunflower colors are not reproduced, but
The decisive drawback of loss of image information based on generation copying can be avoided. Further, as shown in FIG. 1, there are three types of filters 2OR, 20B, and 20G, and three types of toner CT.

When creating an image using YT2MT, the image can be composed depending on whether each of the three types of toner sticks to the transfer material or not, so 2
' = 8 colors (white background, cyan, magenta.

Information can be reproduced using the following colors (yellow, red, green, blue, black), and with so many colors, there is usually no shortage of them. The number of colors of images used for normal office work is about 10 at most, and the output images of color printers for office computers are mostly 3 or 6 colors.

If the number of colors in the completed multicolor image is insufficient at eight colors including black and white as in the above embodiment, the number of colors can be increased by the configuration of the second embodiment described below.

The second embodiment is useful when document information is expressed, for example, not only by a red image and a yellow image, but also by colors in between. Therefore, in this case as well, we will explain the case of copying the original Trff;i3 shown in FIGS. 3(a) and 3(d). Naturally, images S and T are reproduced in orange, tangerine, and sunflower colors, respectively, in red and yellow.

U is reproduced in a tangerine color between red and yellow.

In the second embodiment as well, the processes shown in FIGS. 3(a) to 3(d) are the same as in the first embodiment shown above, and therefore the explanation of the processes up to this point will be omitted.

The difference is that the erase operation is controlled on and off in three stages, and when each latent image shown in FIG. 3(d) passes through the LED array 3, correction exposure is performed as follows.

That is, a large amount of magenta toner adheres to the red latent image R1 on the photoreceptor after correction exposure, and a small amount of magenta toner adheres to the orange, migan, and sunflower latent images SL, Tl, 01, resulting in a yellow image. The surface potential of each portion is adjusted so that no magenta toner adheres to the photoreceptor portion Y1 corresponding to . Specifically, as shown in FIG. 3(i), the red latent image R1, the tangerine latent image T1, and the sunflower latent image U1 are not subjected to corrective exposure by the LED array 3, but their surface potentials are substantially changed. For the orange latent image S1 without changing.

The surface potential is an intermediate value, in this example +300■ to +
An intermediate amount of light L1 is applied by the LED array 3 so that the light intensity is 500 cm (for convenience of explanation).

The on state of the LED array at an intermediate light intensity will be denoted as 172 on). Further, the photoreceptor portion Y1 corresponding to the yellow image Y is irradiated with a normal large amount of light, a complete erase operation is performed, and its surface potential is brought to OV (however, the surface potential of this portion was originally approximately 0). ■Therefore, it is not necessary to perform the erase operation, but if the erase operation is performed, even if a potential remains in this portion Y1, it can be completely erased, which is advantageous, as in the first embodiment. ). Table 1 shows the on/off state of the erase operation by the LED array 3 and the surface potential after correction exposure.
As shown in the erase (2) and Vs' (2) columns, respectively.

Figure 4 shows the above-mentioned process more clearly. If the surface potential Vs before correction exposure is as shown by the solid line X, then 100OV≧Vs as shown on the right side of the figure.
>700V erase operation off, 700v≧Vs
＞500V 1/2 on, 500v≧■s ≧3
At 00 V, 300 V < Vs ≦ OV is on, and the surface potential after correction exposure is <0 V (corresponding to Yl), 300 V to 500 V (7
) area Xi (corresponding to SL, Tl, Ul) and 70
It is clearly divided into three regions: region X2 (corresponding to R2) of 0 to 1000V. The surface potentials of these regions are widely separated from each other and are not continuous.

To actually execute the above control, the color scanner 2
1. As shown in Table 1, the value of the output from the CCD corresponding to the green filter G' is less than 0.3 from O (100OV≧Vs in FIG. 4)7.
The erase operation is turned off for a latent image corresponding to an image of 0.0 V (equivalent to 0.0 V), and similarly, the erase operation is turned off for a latent image corresponding to an image of 0.3 or more and less than 0.5 (equivalent to 700 V≧Vs>500 V). For 1/2 on, also for 0.5 or more, 0.
7 or less (corresponding to 300V<Vs≦Ov), off, from 0.7 to 1 (corresponding to 300V<Vs≦OV)
) may be set in advance so that it is turned on. Note that the judgment (2) column in Table 1 shows the judgment state of the original image in the second embodiment.The latent image after the 6-correction exposure is converted into a toner image by the magenta toner MT, but at that time, the The surface potentials on the body are 3 points apart from each other.
As is clear from FIG. 5, magenta toner does not adhere to the portion Y1 where the surface potential is Ov, and the magenta toner does not adhere to the portion Y1 where the surface potential is Ov, and the magenta toner does not adhere to the portion Y1 where the surface potential is Ov.
Although the amount of toner is small, it definitely adheres to the areas (Tl, Ul), and the toner adheres to the areas (X2;
1), a large amount of toner will definitely adhere to it (Fig. 3 (j)
reference).

By dividing the surface potential on the photoreceptor into three areas in this way, it is possible to clearly distinguish areas to which a large amount of toner adheres, areas to which less toner adheres, and areas to which no toner adheres. .

Therefore, as shown in FIG. 3(k), if the magenta toner image is transferred to the transfer material 25 on which the yellow toner image has already been formed and these are fixed (FIG. 3(Q)), M document 1
The red image R and the yellow image Y of No. 3 are reproduced as red and yellow images R2 and Y2, respectively, and the orange, tangerine, and sunflower images are reproduced as an orange image T2, and these images R2°T2. Y2 is formed clearly divided into three colors. In this case, the orange image T2 has a magenta density in the range of 0.6±0.2 as shown in FIG. Since it is clearly distinguished from the yellow image Y2, there is no problem in expressing the image information.For example, the same information may be displayed in orange on Company A's printer, sunflower color on Company 8's printer, and so on. When Company 0 was expressed in tangerine color, the image T2 obtained by copying this using the above method can be clearly distinguished from images of other colors (R2, Y2), and information confusion does not occur6. Even if the same process is performed using the multicolor image obtained in the second embodiment as an original, and further the same process is performed using the resulting image as an original, the image reproduced in three colors will not be lost. As in the first embodiment, the height of the surface potential of each latent image can be clearly differentiated by the erase operation prior to development with magenta toner, so generation copying is repeated, and during that time the photoreceptor may become fatigued or temperature/humidity changes. This is because even if a change occurs, the image can always be reproduced with almost the same color.

In the second embodiment, when three color toners are used, a multicolor image can be reproduced even with these intermediate colors.
It is possible to obtain a multicolor image with 27 colors, and the number of colors can be significantly increased compared to the first embodiment. The number of colors that can be reproduced in the same way, that is, the areas with differences in surface potential is 4.
If the number of colors is increased in steps, it is possible to reproduce 4'=64 colors. In this case, some programs are semi-low, 8 colors, 2
It is also possible to select between 7 colors, 64 colors, or more, and the normal full-color one-way system, depending on the purpose of copying the original.

In the embodiment described above, a case was explained in which a red image, a yellow image, and an image of an intermediate color between these were reproduced.
It goes without saying that other colors can also be reproduced according to exactly the same idea.

Further, the black image part or the achromatic image part of the gray image part of the document may be reproduced by a toner image in which yellow, magenta, and cyan toners are superimposed. The outputs of the C0D26 corresponding to the three types of filters are compared and calculated, and it is determined whether the pixels on the document that are incident on the three types of filters are chromatic or achromatic, and the chromatic image portion and the achromatic image portion of the document image are determined. It is advantageous to determine the colored image parts and copy them separately.

That is, when copying a chromatic image area, in addition to executing the operations described above, the LED array 3 erases all the latent images on the photoreceptor corresponding to the achromatic image area based on the above discrimination information. . In this way, the chromatic image area is reproduced on the transfer material, but in addition to this operation, another copying operation is performed, and this time, based on the 5 discrimination information, the chromatic image area is reproduced on the transfer material. All the latent images corresponding to the colored image area are erased, and the remaining latent image of the achromatic image area is developed by a black developing device 4 (FIG. 1) containing black toner BLT. In this way, the achromatic image area can be reproduced using only black toner, and a clear image without color shift can be obtained.

The finer the pitch of correction exposure by the LED array 3, the higher the quality of the image that can be formed. However, the resolving power of the human eye for color is said to be 0.30+nm, so even if this pitch is made too thin, A pitch of about 0.25+nm to 2.0m is sufficient, as no great effect can be obtained.

The reading of the original image by the color scanner may be performed by pre-scanning separate from the image exposure of the photoreceptor, and as the color scanner, a device using a photoelectric conversion element other than a CCD may be used as appropriate.

In addition, the erase operation by the erase device is performed before forming the latent image.
Alternatively, the erasing device may be used at the same time to prevent unnecessary latent images from being formed in advance.In addition to the LED array, the erasing device includes a laser, an FL array, a device having a light source, and a PLZT switching array.

Any suitable device can be employed.

Furthermore, the present invention can be applied to any device that uses at least two types of single color separation filters instead of three types.
It is clear from the above-described embodiments that the correction exposure does not necessarily need to be performed every time the photoreceptor is exposed to an image, but may be performed at least every time an image is exposed.

Finally, each of the embodiments shown above will be summarized.

(2) When the maximum output of a photoelectric conversion element such as a COD is set to 1, a latent image whose output corresponds to m to 1 (0<m<1) is corrected and fogged. This corresponds to the first embodiment "A", and in this embodiment, the output of the COD corresponding to the green filter G' is 0.
．． 5 was defined as m.

■ Similarly, 1 is the maximum output, O < n < m 1
When <m2<1, the latent image corresponding to the output direction from 0 to n is not subjected to correction exposure, and for the photoreceptor portion corresponding to n to ml, the potential after correction exposure changes from output m1 to m2. Correct exposure is performed so that the surface potential of the corresponding latent image falls within the range of the surface potential,
The latent image corresponding to ml to m2 is not subjected to correction exposure, and the latent image or photoreceptor portion corresponding to m2 to 1 is exposed to correction (corresponding to the second embodiment).

According to the present invention, even if generation copying is repeated, loss or confusion of image information of a document can be suppressed more than before.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing an example of a copying machine that implements the method according to the present invention, FIG. 2 is a schematic diagram of a filter used in a color CCD, and FIGS. 3 (a) to (U) are according to the present invention. A schematic diagram illustrating the image forming process, FIG. 4 is a graph illustrating the surface potential before and after corrective exposure, and FIG. 5 is the surface potential of the latent image and the density of the toner image when it is converted into a 1-toner image. It is a graph showing an example. 1...Photoconductor 13...Original 2OR, 20
B, 20G... Filter R, S, T, U, Y... Original image R1, SL, TI, Ul, Yl... Electrostatic latent image CT, Y
T, MT...Toner R', G', B'...Filter Figure 3! R2-)--r2-+v2-( Fig. 4

Claims (2)

[Claims] (1) Using at least two types of color separation filters, each photoreceptor is imagewise exposed to light from the original that has passed through each filter to form an electrostatic latent image, and the latent image is used as the filter used for image exposure. In a multicolor image forming method in which development is performed using toners of complementary colors, an original image of an intermediate color between at least two original images is
The latent image or the photoreceptor portion is selectively exposed to corrective light by an erase device during at least one photoreceptor image exposure, or before or after the photoreceptor image is exposed, so that the latent image or the photoreceptor portion is reproduced in a predetermined specific color. A multicolor image forming method. (2) Before or at the same time as at least one image exposure, light from the document is incident on a photoelectric conversion element through red, green, and blue filters for each specific unit of the document,
Claim 1 also includes detecting the output and selectively exposing the photoconductor to corrective exposure so that the electrostatic latent image or the surface potential of the photoconductor is separated into specific ranges separated from each other by an erase device. The multicolor image forming method described.