JPS59221166A - Color image recording method - Google Patents

Abstract

PURPOSE:To realize a recording method with a high recording speed and also without color offset by conducting sequentially the forming and development of an electrostatic latent image corresponding to each chrominance component picture of the three primary colors and forming directly a color visual image on a photosensitive body. CONSTITUTION:The primary electrostatic charging of negative polarity is applied by a charger 11 while turning the photosensitive body 10 in the direction of arrow to charge a voltage of -1,000V and the secondary charging is applied by a positive charger 12 to charge the surface potential of the photosensitive body to 0V. Then the strength of a laser beam L1 is modulated by a picture signal corresponding to a cyan chrominance component image and the image is exposed by the write by means of line scanning. The obtained electrostatic latent image is developed by a developing device 13 by using a cyan toner. Succeedingly, the electrostatic latent image of a magenta chrominance component image and a yellow chrominance component image is obtained by laser beams L1, L2 and each image is developed by developers 14, 15. The image is exposed by a signal corresponding to a black image and the result is developed by a developer 16 so as to obtain a color visual image.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a color image recording method, more specifically, a color image recording method using a photoconductive photoreceptor (prior art) using a photoconductive photoreceptor. Conventionally, as a method for recording color images, Japanese Patent Application Laid-open No. 1986. The method disclosed by No. 2174.2 is known.

In this method, three primary color component images of the color image to be recorded, for example, a magenta color component image, a yellow color component image, and a cyan color component image, are converted into signals, and a laser beam is modulated by these signals. Make it.

After the photoconductive photoreceptor is uniformly charged, it is first imagewise exposed by a laser beam modulated with a signal corresponding to a magenta color component image. The electrostatic latent image formed by this image exposure is developed with magenta toner, and the resulting magenta visible image is transferred onto a recording medium such as paper.

The same process is repeated for the yellow color component image and the cyan color component image, and the yellow visible image and cyan visible image obtained in each process are transferred onto the recording medium.

In this way, a desired color image is expressed by the three primary color visible images superimposed and transferred onto the same recording medium.

The visual images of each color are fixed on the recording medium to obtain a desired color recorded image.

In this method, as described above, the process from the formation of an electrostatic latent image to the transfer of a visible image is repeated for each of the three primary color component images using the same photoreceptor, so one color recorded image is obtained. There is a problem that it takes a long time (15 to 20 seconds).

Another problem is that when the visual images of each color are sequentially transferred onto a recording medium, color misregistration occurs due to mechanical errors.

(Objective) Therefore, the present invention aims to provide a novel color image recording method that has a high recording speed and does not cause the problem of brown color shift.

(Structure) The present invention will be explained below. Two methods are proposed herein. These two methods have the same purpose of recording a color image, and also have the same main parts in common.

Both of these first and second types of methods use a composite photoreceptor in their implementation.

That is, this composite photoreceptor is composed of at least two photoconductive layers laminated on a conductive substrate, and when irradiated with A color light, one photoconductive layer mainly becomes a conductor, and when B color light is irradiated, one of the photoconductive layers becomes a conductor. Depending on the irradiation, the other photoconductive layer is adjusted to primarily become a conductor. Here, at least two photoconductive layers are laminated, which means that in the photoreceptor, a dielectric film may be provided between each photoconductive layer as an intermediate layer or a filter layer, if necessary. However, a transparent dielectric film may be provided as a surface layer on the surface of the upper photoconductive layer.

In the first type of method, first, the two photoconductive layers of the photoreceptor are charged in opposite directions, and the surface potential of the photoreceptor becomes approximately O.

Let α, β, and γ be the three primary colors.

First, an electrostatic latent image corresponding to an α color component image of a color image to be recorded is formed on the photoreceptor by image exposure using an A color light signal. That is, the 9-envelope component image is converted into an image signal and converted into an A color light signal, and an electrostatic latent image is formed by writing with the A color light signal.

This electrostatic latent image is developed with alpha color toner.

Subsequently, an electrostatic latent image corresponding to the β color component image of the color image is formed by image exposure using the A color light signal and the B color light signal, and this electrostatic latent image is developed with the β color toner.

Further, an electrostatic latent image corresponding to the γ color component image of the color image is formed by image exposure using the A color light signal and the B color light signal. This electrostatic latent image is developed with gamma color toner.

In this way, a color visible image is obtained on the photoreceptor. Therefore, this color visible image is fixed on a photoreceptor (if the photoreceptor itself is on a sheet and also serves as a recording medium), or it is transferred and fixed onto a recording medium such as paper.
Obtain the desired color recorded image.

In the second type of method, first, the two photoconductive layers of the photoreceptor are charged to opposite polarities, and the surface potential is brought to approximately O.

Next, the electrostatic latent image corresponding to the α color component image of the chromatic image portion excluding the black image of the color image to be recorded is A.
It is formed by image exposure using color light signals and developed with α color toner.

Further, an electrostatic latent image corresponding to the β color component image of the chromatic image portion is formed by image exposure using the A color light signal and the B color light signal, and is developed with the β color toner.

Subsequently, an electrostatic latent image corresponding to the γ color component image of the chromatic image portion is formed by image exposure using the A color light signal and the B color light signal, and is developed with the γ color toner.

Subsequently, an electrostatic latent image corresponding to the black image area is formed by image exposure using the A color light signal and the B color light signal, and is developed with black toner.

The color image thus obtained is fixed directly onto the photoreceptor, or transferred and fixed onto a recording medium such as paper,
A desired color recorded image can be obtained.

Note that the order of the process for obtaining a black visible image and the process for obtaining a chromatic visible image may be reversed.

The first type of method and the second type of method are basically the same, and therefore have the same main components.

The difference between the two lies in the handling of black recorded images. That is, in the first type method, the black recorded image has α, β,
It is expressed by subtractive mixing of each color toner of γ,
In the second type of method, a black recorded image is represented by black toner. Therefore, a black recorded image is expressed as pure black in the second type of method, and is visually beautiful. However, in order to obtain such advantages, the second type of method requires an extra process to form a black recorded image compared to the first type of method.

This will be explained below with reference to the drawings. As mentioned above, the first
Since the first type method and the second type method are the same in principle, the second type method, which is a more complicated process, will be explained below, and then the differences from the second type method will be explained. The first type of method will be explained.

In FIG. 1, reference numeral 1 indicates a photoreceptor.

This photoreceptor 1 has a photoconductive layer on a conductive substrate BS.

U are stacked in this order. For the sake of simplicity, let us assume that when this photoreceptor is irradiated with A color light, only the photoconductive layer becomes a conductor, and when B color light is irradiated, only the photoconductive layer U becomes a conductor.

Now, when the photoreceptor 1 is irradiated with A color light and only the photoconductive layer is made into a conductor, the photoreceptor 1 is subjected to a corona discharge of a predetermined polarity, for example, a negative polarity, as shown in FIG. As shown in (1), an electric double layer is formed via the photoconductive layer U. Therefore, this state is referred to as the photoconductive layer U being charged. This means that the photoconductive layer U is likened to a capacitor.

Note that if there is a rectifying property for holes between the photoconductive layer and the conductive substrate BS, the irradiation with the A color light is not necessary. The above-mentioned charging step is referred to as primary charging, and the negative charges due to the primary charging are present on the surface of the photoreceptor, and the positive charges are trapped in the photoconductive layer and the "boundary layer" of U.

The surface potential of the photoreceptor becomes negative due to the primary charging.

Subsequently, secondary charging with a polarity opposite to that of the primary charging is performed in the dark. When the negative charge of the primary charge is gradually canceled out by this secondary charge, the balance between the negative charge on the surface of the photoconductor and the positive charge on the photoconductive layer and the U interface is disrupted, resulting in an excess of positive charge. A negative charge, which must be balanced over time, is induced at the interface between the photoconductive layer and the conductive substrate BS.

The surface potential of the photoreceptor gradually decreases with the start of secondary charging, so when this surface potential reaches O, secondary charging is stopped. FIG. 1(U) shows this state. In this state, an electric double layer is formed through each of the photoconductive layers and U, but the two photoconductive layers are charged in opposite directions, referring to the dipole moment vector state in each double layer. It is called Samaruta.

That is, in this state, the photoconductive layers of the photoreceptor 102 are charged in opposite directions, and the photoreceptor surface potential is zero.

Next, image exposure is performed, as shown in Figure 1 (II
In I), the symbol O indicates a color image to be recorded. This color image includes a white background W, a black image portion BL, a cyan image CI, a magenta image kite, a yellow image YE, a red image RE, a green image GRzTc, and a color image B.
Let us assume that it has LU.

Of these, the portion excluding the white background portion W and the black image portion BL is the chromatic image portion.

Here, let us assume that the three primary colors α, β, and γ are yellow, magenta, and yellow, respectively.

Then, the next step is to form an electrostatic latent image corresponding to the cyan color component image by image exposure of the A color light signal.

Σ each color image that constitutes a chromatic image CI, MA, YE,
R.E.

Among GR and BLU, the cyan image CI, the green image GR, and the blue image BLU contain cyan as a component, and these constitute the /A7 color component image. Therefore, the A color light is converted into a signal corresponding to this cyan color component image, and image exposure is performed as the A color light signal (
(Fig. 1 (III)), when the charged state of the photoconductive layer is partially weakened, the surface potential of the photoreceptor becomes negative in the light-irradiated area (by reducing the charged state of the photoconductive layer L, The charged state of the photoconductive layer U becomes dominant). That is,
Due to the negative polarity surface potential distribution, an electrostatic latent image corresponding to the cyan color component image of the chromatic image is formed.

Therefore, this electrostatic latent image is transferred to the positively charged cyan toner Tc.
(Fig. 1GV)).

Next, an electrostatic latent image corresponding to the magenta color component image of the chromatic image is formed by image exposure using the A color light signal and the B color light signal. This will be explained with reference to FIG. 1(V).

At this stage, an electrostatic latent image corresponding to the cyan color component image exists on the photoreceptor 1.

The magenta color component image is a magenta color image style, a red image R
E and a blue image BLU. Therefore, when comparing the magenta color component image and the cyan color component image, the blue image BLU is a common part.

Therefore, in order to form an electrostatic latent image corresponding to the magenta color component image, of the already formed electrostatic latent image corresponding to the cyan color component image, the parts other than the part corresponding to the blue image are erased and replaced with , magenta image style, and red image RE
An electrostatic latent image corresponding to the image may be formed and applied.

Therefore, in order to partially erase the electrostatic latent image, the cyan image C
I, and the electrostatic latent image portion corresponding to the green image GR is B.
It is irradiated with a colored light signal to weaken the charged state of the photoconductive layer U to balance it with the charged state of the photoconductive layer at the relevant portion, and the photoreceptor surface potential is set to zero.

In addition, when the A color light signal irradiates the photoreceptor portion corresponding to the magenta color image and the red image RE to weaken the charged state of the photoconductive layer, a desired electrostatic latent image, that is, a magenta color component image is generated. An electrostatic latent image corresponding to is formed.

Therefore, this electrostatic latent image is transferred to positively charged magenta toner T.
Develop with M (Figure 1 (■)).

Subsequently, an electrostatic latent image corresponding to the yellow color component image of the chromatic image portion is formed.

The yellow color component image is yellow color image YJ red image R
E. Since it is composed of the green image GR, the magenta color image corresponding portion and the blue image corresponding portion of the electrostatic latent image corresponding to the magenta color component image are erased by image exposure using the B color light signal. , The area corresponding to the yellow image and the area corresponding to the green image are newly image-exposed with the A color light signal (FIG. 1 (■)).

The electrostatic latent image thus formed is developed with positively charged yellow toner Ty (FIG. 1 ([)).

Subsequently, in order to form an electrostatic latent image corresponding to the black image area BL, the electrostatic latent image corresponding to the yellow color component image is erased by image exposure using the B color light signal, and the electrostatic latent image corresponding to the yellow color component image is erased by image exposure using the A color light signal. Perform this on the area corresponding to the image area (first
Figure (■)).

The electrostatic latent image thus obtained is developed with positively charged black toner TI3 (FIG. 1(X)).

A color visible image is now obtained on the photoreceptor 1.

All that remains is to fix this visible image directly onto the photoreceptor 1 to create a color recorded image (if the photoreceptor 1 also serves as a recording medium), or to transfer and fix it onto a recording medium such as paper. good.

The above is the second type of method.

When implementing the first type of method, the following may be considered.

That is, in the first type of method, individual electrostatic latent images of three primary color component images of a color image including a black image portion are formed and developed.

As in the case of the above explanation, if the three primary colors α, β, and r are cyan, magenta, and yellow, respectively, the black image area itself is common to all of the cyan color component image, magenta color component image, and yellow color component image. included in.

Therefore, if we explain based on Figure 1, Figure 1 (1)
, After carrying out the step (II), in the step shown in FIG. 1 (US), the photoreceptor part corresponding to the black image area is also imagewise exposed with the A color light signal, so that the black image area is included as a component. By forming an electrostatic latent image corresponding to a cyan color component image and then performing the steps shown in FIG. 1 (IV) to (■), a color visible image corresponding to a color image can be obtained on the photoreceptor 1. After that, the second
All you have to do is change the process similar to the seed method. Note that in the above description, the roles of the A color light and the B color light may be exchanged. In this case, the charging polarity of the toner is set to negative polarity.

The second type of method will be described below using a specific example.

An aluminum drum is used as a conductive base, and on its circumferential surface,
A8°S,3, which is photosensitive up to a wavelength of 780 nm, was deposited to a thickness of 60μ772 to form a photoconductive layer. Next, on this photoconductive layer, a resin filter in which copper phthalocyanine was dispersed was formed to a thickness of about J .mu.m by a dipping method. This resin filter cuts red light, but 6
It transmits light with a wavelength of 00 nm or less and light with a wavelength of 700 nm or more.

On this resin filter, a layer of organic optical semiconductor, so-called OPC, which can be used while being negatively charged, was deposited to a thickness of 15 mm using the tipping method.
A photoconductive layer U was formed.

This photoconductive layer U is primarily sensitive to green light and red light, but is not sensitive to light with a wavelength of 780 nm, allowing it to pass through.

Using this drum-shaped photoreceptor, an apparatus as shown in FIG. 2 was constructed. In the figure, numeral 10 indicates a photoreceptor.

Code 1.1. 12 is charger, code 13.1.4
．． Reference numerals 15 and 16 designate a developing device, 17 a transfer charger, 18 a static eliminating lamp, 20 a cleaning device, 19 a fixing device, and S a transfer sheet as a recording medium, respectively.

In addition, as a light source for image exposure, a semiconductor laser that emits a laser beam with a wavelength of 780 nm and a He-Ne laser that emits a laser beam with a wavelength of 633 nm are prepared. It is now possible to perform image exposure using a line scanning method between devices.

In the figure, the symbol L1 indicates a laser beam from a semiconductor laser. This laser beam is A in the above explanation.
It is exposed to colored light. Further, reference numeral L2 indicates a laser beam from a He-Ne laser, which corresponds to B color light. Each laser beam had a beam spot diameter of 100 μm at the writing position.

While rotating the photoreceptor 10 in the direction of the arrow, the charger 11 performs negative primary charging to bring the surface of the photoreceptor to -1000V, and then the charger 12 performs positive secondary charging to charge the photoreceptor. The surface potential was O. Note that there is rectification of holes between the aluminum drum, which is the conductive base of the photoreceptor 10, and the Ag38e3 photoconductive layer directly formed thereon.

Subsequently, the laser beam L1 is intensity-modulated with an image signal corresponding to the cyan color component image to produce an optical signal, image exposure is performed by writing by line scanning, and the obtained electrostatic latent image is processed by the developing device 13. Developed using cyan toner (positively charged). In the image exposure, the exposure amount was adjusted so that the maximum potential of the electrostatic latent image formed was 1500V.

Subsequently, an electrostatic latent image corresponding to the magenta color component image is formed by image exposure with laser beams Ll and L2 such that the maximum value of the electrostatic latent image potential is 1500 cm,
Developing was performed using the developing device 14 using positively charged magenta toner.

Similarly, image exposure is performed using the laser beams Ll and L2 to form an electrostatic latent image with a maximum latent image potential of -500V corresponding to the yellow color component image, and the developing device 15 applies positively charged yellow toner. It was developed using

Finally, the electrostatic latent image is erased by the laser beam L2, the laser beam L1 is converted into an optical signal with a signal corresponding to the black image area, and image exposure is performed by line scanning writing, and the maximum latent image potential is -1000V. An electrostatic latent image was formed and developed by the developing device 16 using positively charged black toner.

The color visible image thus obtained is transferred to the transfer charger 1.
7 onto the transfer paper S and fixed by the fixing device 19.

Further, after the visible image was transferred, the photoreceptor 10 was charged with a discharge lamp 18 and a cleaning device 20 was used to remove residual toner.

With this method, clear color recorded images can be recorded at 10 to 20 images per minute.
I was able to get it at a speed of 1.

Further, since the positional deviation of the image exposure for writing with the laser beam was about ±10 μm, no color deviation in the obtained color recorded image was visually apparent.

Note that it is possible to prepare one type of each of the two types of laser light sources and use them in time division for each image exposure.

In the example described above, the image exposure using the A color light signal and the image exposure using the B color light signal are performed at the same time, but these may be performed temporally before or after each other.

(Effects) In the color image recording method according to the present invention, electrostatic latent images corresponding to each color component image of the three primary colors are sequentially formed and developed to directly form a color visible image on the photoreceptor. Color image recording can be carried out at high speed, and since each color image is not transferred separately, color misregistration does not occur in the resulting color recorded image.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the present invention, and FIG. 2 is an explanatory front view schematically showing only the main parts of an example of an apparatus for carrying out the second type of method of the present invention. be. ■, 10...Photoreceptor, A...A color light signal, B
...B color light signal, Tc: cyan toner, TM: magenta toner, TY: yellow toner. 2nd figure 17

Claims (1)

[Claims] 1. At least two photoconductive layers are laminated on a conductive substrate, one of the photoconductive layers mainly becomes a conductor when irradiated with A color light, and becomes a conductor when irradiated with B color light. is prepared such that the other photoconductive layer is primarily a conductor; the two photoconductive layers of this photoconductor are charged in opposite directions;
And after setting the photoreceptor surface potential to approximately 0, α, β, and γ are set to 3.
When recording primary colors, an electrostatic latent image corresponding to the α color component image of the color image to be recorded is formed by image exposure using the A color light signal, this electrostatic latent image is developed with α color toner, and then the above An electrostatic latent image corresponding to the β color component image of the color image is formed by image exposure using the A color light signal and the B color light signal, and is developed with β color toner, and furthermore, corresponding to the γ color component image of the color image. forming an electrostatic latent image by imagewise exposure using an A color light signal and a B color light signal and developing it with γ color toner to obtain a color visible image corresponding to the color image on the photoreceptor; A color image recording method, characterized in that a color recorded image is obtained by fixing this color visible image on the above-mentioned luminous body or transferring and fixing it onto a recording medium. 2. At least two photoconductive layers are laminated on a conductive substrate, and one photoconductive layer mainly becomes a conductor when irradiated with A color light, and the other photoconductive layer becomes a conductor when irradiated with B color light. Using a photoreceptor prepared in such a way that it mainly becomes a conductor, the two photoconductive layers of this photoreceptor are charged in opposite directions to each other,
And after setting the photoreceptor surface potential to approximately O, α, β, and γ are set to 3.
When using primary colors, an electrostatic latent image corresponding to the α color component image of the chromatic image area excluding the black image area of the color image to be recorded is formed by image exposure using the A color light signal, and then the electrostatic latent image is formed using the α color toner. Then, an electrostatic latent image corresponding to the β color component image of the chromatic image area is formed by image exposure using the A color light signal and the B color light signal, and is developed with β color toner, An electrostatic latent image corresponding to the γ color component image in the colored image area is formed by image exposure using an A color light signal and a B color light signal, and is developed with γ color toner. forming a latent image by image exposure using an A color light signal and a B color light signal;
By developing with black toner, a color visible image corresponding to the color image is obtained on the photoreceptor, and this color visible image is either fixed on the photoreceptor or transferred/transferred onto a recording medium. A color image recording method characterized by obtaining a color recorded image by fixing.