JPH01246575A - Copying machine - Google Patents

Abstract

PURPOSE:To make the light amount of an exposure lamp obtain enough image reproducing ability when a chromatic color image is reproduced by using a color filter cutting the color component of yellow. CONSTITUTION:Two filters of the color filter Fc and a black filter Fbk are prepared as filter 38 and a specified filter out of them can be preceded into and receded from a light path. The color filter Fc is used when a chromatic color original is chromatically reproduced. For instance, when a hologram lamp is used as the exposure lamp 29 and when a photosensitive body having sensitivity to red color light is used the yellow component of an original is absorbed about 95% and a red component, about 30%. That is, when the color filter Fc is inserted into the light path, the reflection light amount of the chromatic color image irradiated by light is reduced to the same degree as the reflection light of light projected on a black color image. Thus, the light amount of the exposure lamp 29 can obtain enough image reproducing ability.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a copying machine capable of color-separating a multicolor original to form an image of desired colors.

(Prior Art) Conventionally, a copying machine employs a so-called electrophotographic copying process in which an electrostatic latent image is formed by exposing the surface of a photoreceptor to reflected light from an original image, and a developer is supplied to the image to make it visible. 2. Description of the Related Art A multicolor copying machine has been proposed that is capable of reproducing a multicolor original formed in a plurality of colors almost as is.

This multicolor copying machine has red, blue, and green filters that can absorb red, blue, and green wavelength components, respectively, in the optical path of reflected light. For example, when creating a red image, first, A blue filter is provided, and the electrostatic latent image formed on the photoreceptor is exposed to light through the blue filter, leaving only the electrostatic latent image corresponding to the red image and erasing the others. The electrostatic latent image is visualized with a yellow developer and transferred onto a sheet or transfer belt.

Next, a green filter is provided in the optical path in place of the blue filter, and only the electrostatic latent image corresponding to the red image is extracted from among the electrostatic latent images formed on the photoreceptor by the light exposed through the green filter. The remaining electrostatic latent image of the red image is visualized with a magenta developer, and this is superimposed and transferred onto the image formed with the yellow developer, and these magenta and yellow images are transferred. The colors are mixed to form a red image.

(Problem to be solved by the invention) However, as shown in the experiment below, generally,
Since the photoreceptor has extremely low sensitivity to light exposed through a blue filter, there has been a problem in that the amount of light from the lamp must be increased in order to obtain a normal image.

In this regard, three different types of photoreceptors (OPC-A,
When we conducted an experiment on the sensitivity characteristics using 0PC-B, Se-photoreceptor), we found that when using blue, green, and red filters, the amount of light required to obtain appropriate images for each is shown in Table 1 below. As shown in Figures 3 to 3, it was confirmed that the amount of light required especially when using a blue filter was significantly larger than that of other filters. Note that the light amount ratio was calculated according to the following formula based on the exposure lamp voltage measured during the experiment, using the case without a filter as a reference.

E+/Et-(v+/vz)3·' Table-1: 0Pc-A photoreceptor* Even when the exposure lamp voltage was set to 160V, a proper image could not be obtained.

Table-2: 0PC-B photoreceptor Table-3: Se-photoreceptor (means for solving the problem) The present invention was made to solve the above problem, and it reflects the light illuminated on the original image. An electrostatic latent image is formed by exposing the photoreceptor to light through a filter, leaving only the electrostatic latent image corresponding to a predetermined color, erasing those corresponding to other colors, and removing the electrostatic latent image from the photoreceptor. In a copying machine that obtains an image by developing an electrostatic latent image remaining on the body with a predetermined developer, when creating a chromatic image, as the filter,
A color filter that can absorb reflected light from a yellow image is used.

(Example) The present invention will be described below with reference to the accompanying drawings.

j, , , , , ni, copy, fight, purchase, 戊3. .

(1) Photoreceptor section Figure 1 is a schematic cross-sectional view of a multicolor copying machine.
A photoreceptor drum (3), which is an electrostatic latent image carrier, is installed approximately in the middle of the shaft so as to be rotatable in the direction of arrow (a), and the area around the photoreceptor drum (3) is charged along the direction of rotation. A charger (4), an editing eraser (5), a developing device (6), a static elimination charger (11), a transfer device (12), a cleaning device (22), and a main eraser (23) are installed.

The editing eraser (5) has light emitting elements arranged in multiple stages in a holder arranged along the axial direction of the photoreceptor drum (3), and each light emitting element is arranged so that the timing of turning on and off can be controlled individually. It's Nishide.

The developing device (6) has four developing devices (7), -, (10).
), and these as a whole are arranged in the vertical direction [arrow (b)
, (b″) direction], so that developer (toner) can be supplied to the surface of the photoreceptor drum (3) from any developer, and the developer (toner) can be supplied to the surface of the photoreceptor drum (3) from any developer. contains developers containing yellow toner (Ty), magenta toner (Tm), cyan toner (Tc), and black toner (Tbk), respectively.The developing device (6) is arranged vertically as described above. It is not limited to a movable form, but may be of any form as long as it can selectively supply toner of different colors to the photoreceptor drum (3).

The static elimination charger (11) is for weakening the electrostatic attraction force of the toner held on the surface of the photoreceptor drum (3).

(ii) Transfer device The transfer device (12) is used to transfer and hold the toner supplied onto the photosensitive drum (3) onto an endless transfer belt (15). ) has a dielectric material such as polyethylene on the surface of a conductive base made of conductive polyester containing carbon resin, etc., and rollers (13a), . . . , (
13h) is wound and supported. Further, on the outside of the transfer belt (15), there are also rollers (13d) to (13
e) between the static charger (21) and the static elimination charger (
20) are opposed to each other, a cleaning device (19) is opposed to the roller (13e), and a roller (19) located below is opposed to the roller (13e).
13g), (13f) has a transfer charger (24),
Separate chargers (25) are placed opposite each other.

Among the rollers, rollers (13b) and (13c)
), (13e) and (13h) are movable in and out as shown by arrows, and rollers (13b) and (13c
), the transfer belt (15) located between them comes into contact with the outer circumference of the photoreceptor drum (3) and is separated from them, and as the roller (13e) moves, the transfer belt (15)
) is brought into contact with and separated from the blade of the cleaning device (19), and an appropriate tension is applied to the transfer belt (15) as the roller (13h) moves.

Note that a scorotron charger is more suitable for the charger (11) than a corotron charger from the viewpoint of potential stability.

(iii) Optical system An optical system (27) is arranged at the top of the copying machine main body (1). In this optical system (27), the first slider (
28) is equipped with an exposure lamp (29) and a first mirror (31), and the first slider (28) is attached to the copying machine body (
1), it is possible to scan in the direction of arrow (d) along the document table glass (26) provided at the top.

A second slider (32) is attached to the side of the first slider (28).
A second mirror (33) and a third mirror (34) are provided therein, and the second slider (32) moves in the direction of arrow (d) in synchronization with the first slider (28). It is designed to scan at half the speed of one slider (28).

Further, a lens (35) and a fourth mirror (36) are fixed to the front [scan side] of the second slider (32), and a fifth mirror (37) is fixed above the photosensitive drum (3). , a color identification device (30
) is provided. This color identification device (30) is for detecting the color of the original by receiving the reflected light of the light irradiated onto the original from the exposure lamp (29).
0) and the color identification process will be described in detail later.

Furthermore, a filter (38) is provided between the lens (35) and the fourth mirror (36).

(1v) Filter As the filter (38), a color filter (F
c) Two types of filters are prepared: a black filter (Fbk), and any filter from these can be moved forward or backward into the optical path.

The color filter (Fc) is a filter used when reproducing chromatic color originals in color, and as shown in the transmittance characteristics shown in FIG.
9) When a halogen lamp and a photoreceptor sensitive to red light are used, about 95% of the yellow component and about 30% of the red component of the original are absorbed. That is, when this color filter (Fc) is inserted into the optical path, the amount of reflected light of the light illuminated on the chromatic color image is reduced to the same level as the reflected light of the light illuminated on the black image. Further, when a fluorescent lamp is used as the exposure lamp (29), or when a photoreceptor having low sensitivity to red light is used, it is sufficient to use a color filter (Fc) that absorbs only the yellow component. Similarly, a black filter (Fbk) is a filter that uniformly reduces the amount of light in all wavelengths in the visible region, and when creating a monochrome image, reduces the amount of light irradiated on the original image to a predetermined amount or less. It is something that makes you

(v) Paper feeding/conveying system 'f (a copy sheet feeding/conveying system is provided at the bottom of the machine main body (1), and the paper feeding section (40) is connected to the first paper feeding section (40).
1), a second paper feed section (42), and a manual paper feed section (43).

The copy sheet (100) in the first paper feed section (41) is fed by a paper feed roller (44), a pair of conveyance rollers (45), and the copy sheet (100) manually fed from the manual paper feed section (43).
0) is transported by a pair of transport rollers (45), and the copy sheet (100) of the second paper feed section (42) is transported by a paper feed roller (47).
The paper is fed by Then, the fed copy sheet) (1
00) is conveyed by the timing roller (46) to the opposing portion of the transfer belt (15) and the secondary transfer charger (24), and the copy sheet) (+00) that has passed there is conveyed to the conveyor belt (48). is sent to the fixing device (49) by
It is designed to be discharged to a paper discharge section (50).

(2) Copying operation The basic copying operation of a copying machine having the above configuration will be explained with reference to FIG.

When the print switch is turned on with an original (not shown) placed on the original table glass (26), the photosensitive drum (3) moves in the direction of the arrow (
While rotating in the a) direction, its outer peripheral surface is charged to a predetermined potential by discharge from the charger (4).

In the optical system (27), the sliders (28) and (32) scan in the direction of the arrow (d), and the reflected light of the light irradiated onto the document from the exposure lamp (29) is reflected by the mirrors (31), (
33), (34), lens (35), filter (38)
, and mirrors (36) and C37), the image area of the photoreceptor drum (3) is exposed to form an electrostatic latent image.

Next, on the surface of the photoreceptor drum (3), light is applied from the editing eraser (5) to portions corresponding to the leading edge, trailing edge, and both sides of the image area where the electrostatic latent image is formed. The charge is removed by irradiation. Note that when a multicolor image forming mode, which will be described later, is selected, charges of an image corresponding to a predetermined color are also erased based on the detection result of the color detection device (30).

Subsequently, the electrostatic latent image is visualized as a toner image by supplying toner from a predetermined developing device at a portion facing the developing device (6), and then the toner image and the photoreceptor are transferred by the subsequent static elimination charger (11). The electrostatic attraction force with the drum (3) is weakened.

On the other hand, in the transfer device (12), based on the drive of the main motor (2), the rollers (13b) and (13c) move upward to the state shown in FIG.
13b) and (13c), and while being rotated in the direction of arrow (c) in this state, an electric charge is applied to -ti by the charger (21). Ru. Note that the moving speed of the transfer belt (15) is set to be the same as the circumferential speed of the photosensitive drum (3) so that relative movement does not occur between the two.

With the transfer device (12) set as described above, when the toner image formed on the surface of the photosensitive drum (3) is sent to the contact portion with the transfer belt (15), the toner image is transferred to the transfer belt (15). The toner image is primarily electrostatically transferred to the transfer belt (15) based on the charge applied by the charger (2I).

After the photosensitive drum (3) has passed through the area facing the transfer belt (15), residual toner is removed by a cleaning device (22), and then the residual charge is erased by the main motor (23) and the drum is used for the next image formation. Prepare for.

The toner image transferred to the transfer belt (15) is conveyed in the direction of arrow (c) as the transfer belt (15) moves. In addition, when forming a multicolor image, the above-mentioned IV copying operation is repeatedly executed, and toner images formed in each color are transferred onto the transfer bell (15) in an overlapping manner.

On the other hand, the Pυ copy receipt 1 supplied from the paper feed unit (40)
00) is fed out from the timing roller (46) in synchronization with the toner image, and in a portion facing the secondary transfer charger (24), the secondary transfer charger (
Based on the discharge of step 24), the toner image is secondarily transferred onto the 1-gram receipt 100).

The copy sheet (100) on which the toner image has been transferred is separated from the transfer belt (15) by a separation charger (25) and conveyed to a fixing device (49) by a conveyor belt (48), where the toner image is After being fused and fixed, the paper is delivered to the ejecting section (
50).

The transfer belt (15), which has lost toner after passing through the section facing the second transfer charger (24), has residual toner removed at the section facing the cleaning device (19).
The residual charge is erased by the static elimination charger (20) in preparation for the next transfer operation.

＠、、、、、、Susumu、Identification Department Hadagasa The color identification process will be explained below.

The color identification device (30) is arranged in parallel with the photoreceptor drum (3).
It is formed by continuously arranging photoelectric conversion elements (hereinafter referred to as "CCD sensors") (30a) each having a width of 1.5 to 2 mm. The CCD sensor (30a) detects three primary colors of light, red (R), from the reflected light of the light illuminated on the object;
It is equipped with three photodiodes (L Dg, LDb) that detect green (G) and blue (B) components, respectively, and the color of non-illuminated objects is identified based on these outputs.

Note that the photodiodes (LD r , LDg,
LDb) illuminates objects in three primary colors: red (R), green (G), and blue (B), and is adjusted in advance so that the respective outputs are the same.

Next, the operation of color identification processing is performed according to the flowchart of FIG.

When the copying operation starts and the optical system (27) is driven, at (C1), the CCD sensor (30a) detects the reflected light from the original, and each photodiode (L
The output signals of Dr, LDg, LDb) are input as analog signals. That is, the color of a minute area formed by minutely dividing a document vertically and horizontally is detected in a form separated into three elements: red (R), green (G), and blue (B).

Next, in (C2), the analog signal is converted into a digital signal (f
r, fg, fb) and stores the digital signal in memory A at (C3).

Then, at (C4, C5), the digital signal (fr).

fg, rb), red (
R).

Color discrimination coefficients (kr', kg', kb') representing the weights of green (G) and blue (B) are calculated according to the following formula.

In addition, each coefficient of color discrimination coefficient (kr'), (kg'
), (kb'), the first reference value (α) and the second reference value (β) (β<α) are compared in size, and the color is converted as follows, and the color identification data (D ) (kr, kg
, kb).

When α≦(kr' + kg' r k"), kr
, kg, kb=2β>(kr',kg'
, kb'), kr, kg, kb=0β
When ≦(kr' + kg' r kb') < a, kr, kg, kb = 1. Then, based on the combination of these color identification data (D Xkr, kg, kb), the color of each minute area is The table below shows the reproduced colors.
According to I, for example, if (2,2°0) then yellow (
Y), (2,0,2), then magenta (M) is determined. Note that the right column of Table 1 shows the colors of toners used to reproduce each color and the order in which they are developed.

Table 4 Next, in (C6), when image editing such as masking to erase part of the image or trimming to erase part of the image is specified by an editor, input of data regarding the editing area is accepted. Then, in (C7), the document position corresponding to the editing area is recognized, and the corresponding color recognition data is rewritten to a predetermined value. Then, in (C8), the color identification data is stored in memory.

(2) Multi-color image forming method Next, the operation when the copy mode of the copying machine is set to the multi-color image forming mode will first be briefly explained, and then explained in detail.

B. General operation explanation Using the above-mentioned copying machine, yellow (Y), magenta (M),
When reproducing a six-color image of cyan (C), green (G), red (R), and black (Bk), the following table-
The four steps shown in No. 5 are sequentially executed.

[Margin 1 below Table 5 a, Yellow (Y), magenta (
M), cyan (C), green (G) and red (R)
visualize the image.

Note that in these steps, color filters (F, c) are used as the filters (38).

First, in the first step, electrostatic latent images corresponding to yellow (Y), green (G), and red (R) images are formed on the surface of the photoreceptor drum (3), and these are transferred to yellow toner (T).
y), and the toner image is primarily transferred onto the transfer belt (15).

b. In the second step, electrostatic latent images corresponding to magenta (M) and red (R) images are formed on the surface of the photoreceptor drum (3), and this is developed with magenta toner (Tm). The toner image is primarily transferred onto the transfer belt (15) onto which the yellow toner (Ty) has been transferred. At this time, in the red (R) image area, the yellow toner (Ty) has already been transferred in the first step, and the magenta toner (Tm) is superimposed and transferred on top of the yellow toner (Ty).

In the C third step, cyan (
C), an electrostatic latent image corresponding to a green (G) image is formed, this is developed with cyan toner (Tc), and the toner image is primarily transferred onto the transfer belt (15). At this time,
In the green (G, ) image area, yellow toner (T y) has already been transferred in the first step, and cyan toner (T c) is superimposed and transferred on top of the yellow toner (Ty).

d. Finally, in the sixth step, a black (BK) image is visualized. Note that a black filter (Fbk) is set as the filter (38) in place of the color filter (Fc).

Then, black (BK) is applied to the surface of the photoreceptor drum (3).
An electrostatic latent image corresponding to the image is formed, this is developed with black toner (Tbk), and the toner image is transferred (
15) Primary transfer is performed on the top.

f. The toners transferred onto the transfer belt (15) in the above manner are collectively transferred onto the copy sheet (100), and the toners are yellow (Y), magenta (M), cyan (C),
A black (BK) image is reproduced with the corresponding color toner, and a green (G) image is reproduced with yellow (Y) and cyan (C).
), and red (R) is reproduced by mixing yellow (Y) and magenta (M).

(B) Detailed Description The details of the multicolor image forming operation will be described below with reference to the flowcharts of FIGS. 4 to 8 and the process diagrams of FIGS. 9 to 15. Note that the process diagrams in Figures 9 to 15 are
As shown in the figure, the original FA (OD), which has a six-color image of yellow (Y), magenta (M), cyan (C), green (G), red (R), and black (Bk), is reproduced as is. It is a diagram showing a process.

(1) First King's Step: Sl (see Figure 4) When the power is turned on to the copying machine and the program starts, the copying machine is initialized in (3101), and the number of copies is set to "1", for example. . (3102) accepts input from various keys such as a numeric keypad on an operation unit (not shown) provided on the top of the copying machine main body (1).

In this state, when the print switch is turned on, the lamp (29) lights up and the slider (28) moves in the direction of the arrow (d).
Pre-exposure is performed by pre-scanning in the direction (S10
3) The reflected light of the light illuminated on the original is transmitted to each CCD sensor (
30a) (3104). Next, the CCD
Based on the detected value of the sensor (30a), the color identification process (2) is executed as described above, and the color of each minute area formed by subdividing the document into vertical grooves is identified, and the color identification data (DI) is It is memorized (S104°105).

Next, based on the color identification data (DI), it is determined whether or not there are image areas of yellow (Y), green (G), and red (R) in the document (S106); Proceed to step 2 (S2), and if there is any one color, it is determined whether the original is a monochrome image of yellow (Y) or not (310).
7) If it is a single color of yellow (Y), it is a monochrome process.

If the color is not yellow (Y), proceed to (3108) below and change the filter (27) of the optical system (27).
A color filter (Fc) is set as (38).
S108).

Note that in (3106) above, when the copying operation is started, the process is executed using the color identification data (Di),
At the time of multi-copying, processing is executed using color identification data calculated in the Ike process described below.

When the above operations are completed, the rotation of the photoreceptor drum (3) [
Photoconductor section], the yellow developing device (7) of the developing device (6)
) is set in a developable state (S 109), and the surface of the photoreceptor drum (3) is charged to a predetermined potential (S 109).
11O), turn on the exposure lamp (29) and turn the slider (
28) scans the document, and the reflected light of the light illuminated on the document is exposed to the photosensitive drum (3) via the color filter (Fc), forming an electrostatic latent image (S111).

At this time, the yellow component of the reflected light and the red light used for light source correction are cut off.

Therefore, as shown in FIG. 10(a), the reflected light of the light illuminating each color image is hardly exposed to the photoreceptor drum (100), and the potential of the corresponding portion is also in the state at the time of charging. The electrostatic latent images (I y, I m
+ I C, I L r r, Ibk) are formed.

Also, during the exposure, the CCD sensor (30a) detects reflected light (S117), and color identification processing (2) is executed based on the output, and the color identification data (D2) of each area is stored in memory (S118). . The results are used in the second step (S2) to be executed later.

Then, around the photoreceptor drum, the color identification data (D
l) or turning on each light emitting element of the editing eraser (5) individually based on the color identification data of the color identification process executed immediately before;
With off control, electrostatic latent images (Iy, Ig.

Only Ir) is left, and the potential of the other regions is lowered to approximately OV (S112).

Note that the color identification process (■) and the editing/erase operation are performed almost simultaneously, but the color identification data (D2
) is stored in a new memory, the previously stored color identification data (Dl) is output to the editing eraser (5), and the editing eraser (5) erases the color identification data (D2) based on the color identification data (D2). It will never be executed.

Next, the electrostatic latent image (Iy, Ig, Ir) is supplied with yellow toner (Ty) from a yellow developing device (7) at a portion facing the developing device (6), as shown in FIG. 12(b). As shown, it is visualized as an image of yellow toner (Ty) (Sl13).

In the transfer device (11), the surface of the transfer belt (15) is charged to a predetermined potential by the charger (21) (S119), and the outer peripheral portion of the transfer belt (15) or the photoreceptor drum (3) is charged. As shown in FIG. 10(c), the image of the yellow toner (Ty) is transferred to the transfer belt (
15) Primary transfer is performed on the image (S 114.120), and the process proceeds to the next second step (T2).

After residual toner is removed from the surface of the photoreceptor drum (3) (S115), any residual charge is removed (8116).
, proceed to the next second step (S2).

In addition, in the paper feeding system, the iffff-t (100) is rotated by the timing roller (
46) (S121), and proceeds to the next second step (P2).

(11) Second process: S2 (see Figure 5) Second process (S2
) is yellow (Y) when the first step (Sl) is completed or at (8106) of the first step (Sl),
This is a process that proceeds when it is determined that there is no image of either green (G) or red (R) in the document.

First, in this step (S201), magenta (M ), red (R), and if there is, the process proceeds to (S202); if not, the process jumps to the third step (S3).

Next, it is determined whether the original is composed of a single color of magenta (M) (S202), and if it is a single color of magenta (M), the process proceeds to a single color process (SO), otherwise, a color filter (Fc) is applied. is set in the optical path (S203).

Then, around the photoreceptor drum, there is a magenta developer (8).
The surface of the photoreceptor drum (3) is charged to a predetermined potential by the charger (4) (S205), and the optical system (27) is driven to convert the original image into a developable state (S204). The electrostatic latent image (Iy, 1m, lc, Ig, lr, Ib
k) is formed (8206). In addition, CCD sensor (3
0a), the reflected light is detected, color identification processing (2) is executed based on the output, and new color identification data (D3) is stored in memory (S212-213).

Next, an editing eraser (5) is placed on the surface of the photoreceptor drum (3).
), the light is irradiated with magenta (M).

Only the electrostatic latent image (1 m, Ir) corresponding to the image of R is left, and the potential of the other areas is lowered to approximately OV (S20?).

Therefore, in the next developing operation, magenta toner (T m) is supplied only to the electrostatic latent image (1m, lr) (8208
) [see FIG. 11(b)].

The magenta toner (
Tm) is charged by the charger (21) and becomes (
S 214), the toner is primarily transferred onto the transfer belt (15) on which the yellow toner (Ty) has already been transferred in the first step (Sl) (S 209.215), and especially the red (R
), magenta toner (Tm) is superimposed on yellow toner (T'y).

Here, in order to prevent a misalignment between the toner image formed with the yellow toner (Ty) and the toner image formed with the magenta toner (Tm), an optical system (27
) and the operation timings of the photosensitive drum (3) and the transfer belt (15) are adjusted, so that the toner images are superimposed without misalignment. Note that this adjustment is performed electrically and can be performed with high precision.

When the primary transfer is completed as described above, residual toner and residual charges are removed from the surface of the photoreceptor drum (3) (S
210.211), proceed to the next third step (S3).

On the other hand, in the transfer device (11) and the paper feeding system, the document image is changed to yellow (Y) or magenta (
M), red (R), and whether the original is made up of only yellow (Y), magenta (M), and red (R).
), the third step (T
3), proceed to (P3) (3216, 221).

Furthermore, if the document is composed of only yellow (Y), magenta (M), and red (R), the timing roller (
The copy sheet (100) is conveyed from the copy sheet (100) to the opposing portion of the secondary transfer charger (24) (S222), and the toner image on the transfer belt (15) is secondarily transferred to the copy sheet (100) (S222). S 217.223).

Then, in the transfer device (11), residual toner and residual charge are removed (S218, 219), and if the multi-copy mode is selected, the process moves to (Mu), and if the transfer device is in the single-copy mode, the operation is stopped (S220). In the paper feeding/conveying system, the copy sheet (100) is conveyed to the transfer device (49), and after the toner image is fixed, yellow (Y) and magenta (M
), the copy sheet (100) on which the red (R) toner image is formed is discharged to the paper discharge section (50) (S225);
If it is multi-copy mode, the process moves to (Mu), and if it is single-copy mode, it stops (3226).

(iii) Third step: 83 (see Figure 6) Third step (
S3) is a process that proceeds when the second step (S2) is completed or based on the determination result of (3201) of the second step (S2), and the flow of operations is almost the same as the second step. , the only difference is the content of the judgment.

First, in (3301), it is determined whether there is an image of either cyan (C) or green (G) in the document based on the color identification data of the color identification process that was performed immediately before. If there is, proceed to step (5302); if not, proceed to the fourth step (S4).
) to jump to.

Next, in (3302), it is determined whether or not the original is composed of a single color of cyan (C), and if it is a single color of cyan, the process proceeds to the single color process (SO), otherwise the document is filtered using a color filter (F
c) is set in the optical path (3303).

Around the photoconductor drum, after setting the cyan developing device (9) to a developing state, the surface of the photoconductor drum (3) is charged to a predetermined potential, and the optical system (27) exposes the original image to a static state. Electro latent image ([y, 1m, Ic, Ig, Ir
.

1bk) (3304-306). Also, CC
The D sensor (30a) detects the reflected light, and based on the result, the color identification process (2) is executed, and the color identification data (D4) of the document is stored again (S312, 313).

Next, an editing eraser (5) is placed on the surface of the photoreceptor drum (3).
As shown in FIG. 13(a), the electrostatic latent images (I) corresponding to cyan (C) and green (G) images are
c, [g) are left, the surface potential of the other regions is lowered to approximately Ov, and cyan toner (Tc) is supplied only to the electrostatic latent images (Ic, Ig) (330 g).

The cyan toner (Tc) is as shown in FIG. 13(b).
As shown in FIG.
), (3309), (S310). Here, in the part corresponding to the green (G) image, yellow toner (
Cyan toner (Tc) is superimposed on the toner (Ty).

When the above-mentioned next transfer operation is completed, the photosensitive drum (3)
Residual toner and residual charges are removed from the surface of (S31G)
, (S311), and proceeds to the next fourth step (S4).

On the other hand, the transfer device (Il) and paper feeding system must determine whether the original image consists of only cyan (C) and green (G) based on the color identification data (D3) S31.6 ．．
321), if the document contains colors other than cyan (C) and green (G), the fourth step (T4) is performed, respectively.
, proceed to (P4).

Furthermore, if the original is composed of only yellow (Y), magenta (M), cyan (C), green (G), and red (R), the toner image on the transfer belt (15) will be transferred to the copy sheet. Next transcribed (S 317.322.323).

Then, the transfer device (11) removes residual toner and residual charge, and if the multi-copy mode is selected (Mu
), and in the single copy mode, the operation is stopped (3318 to 32o).

In the paper feed/transport system, after fixing the toner image on the copy sheet (100), toner images of yellow (Y), magenta (M), cyan (C), green (G), and red (R) are ejects the copy sheet on which is formed to a paper ejecting section (50),
When in multi-copy mode, proceed to (M u ), and when in single-copy mode, stop (S324 to 326).
).

(iv) Fourth step: 84 (see FIG. 7) The fourth step is a step proceeding directly from the end of the third step or from (S301).

First, it is determined whether or not there is a black (Bk) image in the document based on the color identification data calculated immediately before in (S401), and if there is, it is determined whether or not it is a monochromatic black (Bk) image. However, if it is a monochrome image of black (Bk), the monochrome process (S
Proceed to step O) and set a black filter (Fbk) in the optical path if the color is not monochrome black (Bk).

If it is determined that there is no black (Bk) image in the document, the process proceeds to (M u ) if the multi-copy mode is selected, and the operation ends if the single copy mode is used (S401 to S40).
4).

Next, around the photoconductor, the black developing device (Bk) of the developing device (6) is set to a developing state, and the surface of the photoconductor drum (3) is charged, and then the original image is exposed. Then, an electrostatic latent image (Ibk) of a black image is formed (see FIG. 13(a)) (S405 to 407). In parallel with this,
The CCD sensor (30a) detects the reflected light of the original, executes color identification processing (2), and calculates color identification data (D7) (S
414.415).

In addition, the editing eraser (5) leaves only the electrostatic latent image (r bk) corresponding to the black (Bk) image and lowers the potential in other areas to approximately OV, as shown in Fig. 13<a>.
As shown in , black toner (T bk) is supplied only to the electrostatic latent image (Ibk), and this black toner (T
bk) is primarily transferred to the charged transfer belt (15) [see FIG. 13(b)] (3408-410°416.417).

In this way, the transfer belt (+
5) The toners transferred onto the copy sheet (100) are collectively transferred to the copy sheet (100), which is fed from the paper feed system, and in this way a six-color image is formed on the copy sheet. (1oo) passes through the fixing device (49) to the paper ejection section (50).
), if it is multi-copy mode, it moves to (Mu), and if it is single-copy mode, it stops (S418.
423-426).

Note that the photoreceptor drum (3) and transfer belt (15) have their residual toner and charge removed, respectively, in preparation for the next image forming operation, and if in multi-copy mode, proceed to (MU);
If in single copy mode, stop (S411~
413, 5419-421).

In the above process, in the area where toners of a plurality of colors are transferred, the toner located in the lower layer on the transfer belt (15) appears in the upper layer on the copy paper.

By utilizing this characteristic and changing the amount of two types of toners attached to the upper layer and the lower layer, it is possible to change the tone of the intermediate color reproduced using the two types of toners.

(v) Single color process: SQ (see Figure 8) This single color process (SO) is the first to fourth process (Sl-3
6), the original is yellow (Y) or magenta (M)
, cyan (C), or black (Bk).

In this monochrome step (So), a filter corresponding to the color of the original is set in (SIO). Specifically, if the original is a single color of yellow (Y), magenta (M), or cyan (C), a color filter (Fc) is set,
If the color is a single color (Bk), a black filter (Bk) is set.

Next, around the photoconductor, a developing device containing toner of the same color as the original is set in a developing state, and the photoconductor drum (3)
The surface of the is charged to a predetermined potential, and the optical system (27
), the image is exposed to light to form an electrostatic latent image, and the electrostatic latent image is visualized with toner of a predetermined color (320-2
3).

Then, the toner image is transferred to a charged transfer belt (
15) Primary transfer is performed on the image (S24, 30°31).

The toner transferred to the transfer belt (15) is transferred to the paper feed section (4).
0), and the copy sheet passes through the fixing device (49) and is discharged to the paper discharge section (50) (S32, 340-42).

In addition, the photosensitive drum (3) and transfer belt (15) are cleaned of residual toner and electric charge, respectively, in preparation for the next image forming operation, and if the multi-copy mode is selected, the monochrome process (SO) is resumed. is executed (S25, 26, 33
, 34.50).

(2) Other Embodiments In the above embodiment, the CCD sensor (30a) performs the color identification process in each process, but one unit advances during the preliminary scan operation, and thereafter the data is It may also be possible to perform image processing using this information.

Further, in the above embodiments, the original image is reproduced in that color, but the original image may be reproduced in a different color, for example, a yellow image is reproduced in magenta.

(Effects of the Invention) As is clear from the above explanation, in the present invention, when reproducing a chromatic color image, a color filter that cuts the yellow color component is used, and in particular, a color filter such as a blue filter is used. Since the exposure amount does not drop significantly, at least sufficient image reproduction ability can be obtained by using the exposure lamp in advance.

Furthermore, since it is not necessary to select a corresponding filter for each color, control becomes easier.

[Brief explanation of the drawing]

Figure 1 is a schematic cross-sectional view of the copying machine, Figure 2 is a diagram showing the transmittance characteristics of color filters, Figure 3 is a flowchart showing the color identification process, and Figures 4 to 8 are the multicolor image forming process. 4 shows the first step, FIG. 5 shows the second step, FIG. 6 shows the third step, FIG. 7 shows the fourth step, FIG. 8 shows the monochrome step, and FIG. 9 shows the original image. Figures 10 to 13 are diagrams showing the image creation process.
Figure 0 [Figure 10 (a) to (C)] is the first step, Figure 11 [Figure 11 (a) to (c)] is the second process, Figure 12 [Figure 12 (a), (b)] is the third step, FIG.
Figures 3 (a) and (b) show the 4th step, Figure 14 shows the adhesion state of toner secondary transferred to the copy sheet, and Figure 15 shows the image created in the 1st to 4th steps. It is a diagram. l... Copying machine main body, 3... Photosensitive drum, 4...
Transfer charger, 5... Edit eraser, 6... Developing device, 7... Yellow developer, 8... Magenta developer, 9... Cyan developer, 10... Black developer, 11 ...Transfer device, 15...Transfer belt, 19.
... Cleaning device, 20 ... Static elimination charger, 2
1... Electrostatic charger, 24... Transfer charger,
27...Optical system, 28...First slider, 29...
- Exposure lamp, 30... Color identification device, 30a... Photoelectric conversion element, Fc... Color filter, Fbk...
Black filter, Ty...yellow toner, Tm...
...Magenta toner, Tc...Cyan toner, Tbk...Black toner. Patent applicant: Minolta Camera Co., Ltd. agent, patent attorney: Seihaku Ao, and 1 other person! a 1 Figure 3 Figure 8 Sheep @Gora Figure 5

Claims (1)

[Claims] (1) An electrostatic latent image is formed by exposing the photoconductor to the light reflected from the light that illuminated the original image through a filter, leaving only the electrostatic latent image that corresponds to a predetermined color, and leaving the remaining electrostatic latent image. When creating a chromatic image in a copying machine that obtains an image by erasing those corresponding to the colors and developing the electrostatic latent image remaining on the photoreceptor with a predetermined developer, as the filter, A copying machine characterized by using a color filter that can absorb reflected light from a yellow image.