JPS61113074A - Image forming method - Google Patents

Abstract

PURPOSE:To reproduce sharply an image consisting of chromatic and achromatic colors with high accuracy by using the 1st electrostatic charge image of a positive formed on an image carrying body as the 1st image information and using the positive and negative ion currents passing through an ion current control screen as the 2nd image information. CONSTITUTION:The entire surface of a photosensitive screen 17 and a photosensitive layer 56 are electrostatically charged to negative and are subjected to image exposure by the light from an original 44. A dichroic mirror 47 reflects the light of an R component and allows the transmission of B and G components. The negative charge is left as the image information of the positive on the screen 17 and the layer 56. The positive particles pass selectively through the negative electrostatic charge region of the screen 17 and the negative ion particles pass through the region where the screen is not electrostatically charged to negative when the positive and negative ion particles are projected from a charge particle source 19. The charge of the positive or negative polarity is then left on the layer 56 by the negative charge on the layer 56 and the electrostatic latent image separated with the positive or negative chromatic levels G, B, C and negative chromatic levels Y, R, M on both sides of the achromatic levels (w), (b) is formed. The optional chromatic color is formed to a visible image by development.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an image forming method, particularly an image reading method for simple color discrimination between chromatic colors and achromatic colors, and furthermore, between chromatic colors, and printer copying. It is about the method.

BACKGROUND OF THE INVENTION Conventionally, as color image processing, for example, color printing, electrophotography, image signal processing of color scanners, etc. are known. In all of these, it is necessary to obtain three color information by color separation of three primary colors (blue, B, green, G, and red R) for image formation. For example, according to a known full-color process electrophotographic copying machine, for example, after a photoreceptor is charged with corona, an original image is exposed through a red filter, developed with a cyan developer, and the resulting cyan visible image is once placed on copy paper. Transfer to. Next, the photoreceptor is exposed with a green filter in the same manner as above, and after development with a magenta developer, a magenta visible image is transferred onto the same copy paper in alignment with the cyan image. Further, the same process as above is repeated using a blue filter and a yellow developer, and the image is transferred to match the previous two images. Then, if necessary, the final color image of the print is fixed.

On the other hand, masking technology, which is a color correction method in color printing, is known as image processing based on two color information. For example, according to the positive masking method, at the platemaking stage for each color, an uncorrected color separation negative image is superimposed with a separation positive image of the required density created from another color separation negative image. Color corrections are being made.

A technique in which such a masking method in printing is applied to electrophotography is disclosed in Japanese Patent Application Laid-Open No. 52-3430. According to this known technique, a first static charge image is formed on a photoreceptor, a second static charge image is formed on a photosensitive screen, and a first static charge image is formed in accordance with the second static charge image. Techniques are known in which a first electrostatic charge image is modified by irradiating a charge stream of opposite polarity. For example, magenta color can be reproduced by this, but this is only based on the premise of color correction. Therefore, it is not intended to separate chromatic colors from achromatic colors, and in particular it is not possible to separate chromatic color levels on either side of an achromatic color level.

C. Purpose of the Invention The purpose of the present invention is to sharply produce images consisting of chromatic colors and achromatic colors.
The object of the present invention is to provide a method that is highly efficient, controllable, and easily reproducible.

2. Structure of the invention, that is, the image forming method according to the present invention obtains a plurality of image information from an original image, and when combining these image information to separate the chromatic latent image potential from the achromatic color potential level, A positive electrode that takes a positive first electrostatic charge image formed on the image carrier as first image information and selectively passes through the ion flow control screen according to a second electrostatic charge image formed on the ion flow control screen. The present invention is characterized in that each of the polarity and negative polarity ion flows is used as second image information.

In a preferred embodiment of the present invention, the first electrostatic charge image is formed by a process including exposure to a cyan component, and the second electrostatic charge image is formed by a process including exposure to a red component. Alternatively, the first electrostatic charge image is formed by a process including exposure to a red component, and the second electrostatic charge image is formed by a process including exposure to a cyan component.

According to these embodiments, each electrostatic charge image is formed by exposure of cyan component and red component, but since the spectral characteristics of general red are closest to the ideal spectral characteristics of red, The reproducibility of red images becomes very good.

E, Example Embodiments of the present invention will be described in detail below with reference to the drawings.

First, referring to FIG. 1, an example of an image forming process using a photosensitive screen 17 (the structure of which is shown in a simplified diagram in FIG. 1) will be described.

Photosensitive screen 17 and photosensitive layer 56 of main photoreceptor 1
First, the entire surface of the document 44 is negatively charged, and then imagewise exposed with light from the document 44 . At this time, the dichroic mirror 47, which will be described later, has the function of reflecting the R component light of the light reflected from the original (i.e., as a red filter) and transmitting the B and G component lights (i.e., as a cyan filter). use something As a result, the photosensitive screen 17 and the photosensitive layer 56 have a predetermined amount of negative charges as positive image information (that is, the former is information [R] and the latter is information [C]) as shown in the figure.
will be left as. Then, while the polarity of the charged particle source 19 is alternately switched between positive and negative by the alternating current power source ACs, positive ion particles and negative ion particles are respectively projected from the same particle source 19. Of these, positive ion particles selectively pass through negatively charged regions of the photosensitive screen 17, negative ion particles selectively pass through non-negatively charged regions of the photosensitive screen 17, and further Both of these ion particles reach the photosensitive layer 56. As a result, a new combined electrostatic charge image is formed by the negative charges on the photosensitive layer 56 and the respective charges of the positive and negative ion particles that have passed through the photosensitive screen 17 (in the drawing, a new combined electrostatic charge image is formed). (Bias omitted.) As a result, a positive or negative polarity charge is selectively left on the photosensitive layer 56 with a predetermined amount of charge, and a first group of positive or negative chromatic colors is left on both sides of the achromatic color levels W and b. Levels G, B, C and negative second group chromatic color level Y
, R, and M are separated to form an electrostatic latent image.
Therefore, in the next development, any chromatic color can be visualized.

In this process, photoreceptor 1 and photosensitive screen 1
7, a dichroic mirror 47 which will be described later has both a cyan filter and a red filter function, but since the general red spectral characteristics are closest to the ideal red spectral characteristics, The reproducibility of red images is extremely good.

FIG. 2 shows an image forming process according to another example.

According to this example, the entire surface of the photosensitive screen 17 and the photosensitive layer 56 of the main photoreceptor 1 is first negatively charged, and then the original 44
image exposure with light from At this time, B of the reflected light from the original is used as a dichroic mirror 47 to be described later.
, to reflect the G component light, i.e. as a cyan filter)
, transmits R component light (i.e., as a red filter)
Use something that has functionality. As a result, a predetermined amount of negative charge is left on the photosensitive screen 17 and the photosensitive layer 56 as positive image information (that is, the former is information [C] and the latter is information [R]) as shown. Then, while the polarity of the charged particle source 19 is alternately switched between positive and negative by the AC power source AC1, positive ion particles and negative ion particles are respectively projected from the same particle source 19. Of these, positive ion particles selectively pass through negatively charged areas of the photosensitive screen 17 depending on the amount of charge, while negative ion particles pass through areas of the photosensitive screen 17 that are not negatively charged or negatively charged areas. The ion particles selectively pass through a region with a small amount of charge, and further, these ion particles reach the photosensitive layer 56.

As a result, a new combined electrostatic charge image is formed by the negative charges on the photosensitive layer 56 and the charges of the positive and negative ion particles that have passed through the photosensitive screen 17. As a result, a positive or negative polarity charge is selectively left on the photosensitive layer 56 with a predetermined amount of charge, and a first group of positive or negative chromatic colors is left on both sides of the achromatic color levels W and b. An electrostatic latent image is formed in which the levels Y, R, M are separated from the negative chromatic color levels G%B, C of the second group. Therefore, in the next development, any chromatic color can be visualized.

Also in this process, when exposing the photoreceptor 1 and the photosensitive screen 17, the dichroic mirror 47 (described later)
Since a filter having both cyan filter and red filter functions is used as the filter, the reproducibility of the red image is very good for the same reason as mentioned above.

FIG. 3 shows an image forming process according to yet another example.

In this example, as the dichroic mirror 47 described later,
Among the reflected light from the original, a filter is used that has the function of reflecting B component light (i.e., as a blue filter) and transmitting G and R component light (i.e., as a yellow filter). As a result, the photosensitive screen 17 and the photosensitive layer 5
6, a predetermined amount of negative charge is left as positive image information (ie, the former as information CB) and the latter as information [Y:l), as shown in the figure.

Then, when positive and negative ion particles are projected from the charged particle source 19, a new combined electrostatic charge image is formed by the negative charges on the photosensitive layer 56 and the positive and negative charges that have passed through the photosensitive screen 17. be done. That is, negative or positive polarity charges are selectively left on the photosensitive layer 56 with a predetermined charge amount, and the first group of positive or negative chromatic color levels are placed on both sides of the achromatic color levels W and b. G, Y, R and negative second group chromatic color level M
, B, and C are separated to form an electrostatic latent image.

Therefore, in the next development, any chromatic color can be visualized.

FIG. 4 shows an image forming apparatus implementing the above-described process using a photosensitive screen. A reciprocating document table 61 is provided at the top of the main body of the apparatus, and this document table 61
The document 44 placed thereon is illuminated by the illumination lamp 62 . 63.64 is a mirror, 39 is a fixed lens, 47
is a movable dichroic filter that reflects a predetermined chromatic color light and allows light of a complementary color to the chromatic color to pass, and can be moved in and out of the optical path.

A photosensitive layer 56 is provided on the surface of the drum-shaped photoreceptor 1, and when the photoreceptor 1 rotates clockwise, the photosensitive layer 56 is uniformly charged by the corona charger 24. The photosensitive layer 56 is made of selenium, an organic semiconductor, or the like.

Around the photoreceptor 1, there are a charger 24 for uniformly charging the photosensitive layer 56, and chargers 48 and 49 containing toner of each color.
・・・・・・・・・(However, actually G, Y, R.

A developing device for a desired color among M, B, C, and b is arranged, and two developing devices are shown as an example in the drawing. ) etc. are arranged.

On the other hand, a cylindrical photosensitive screen drum 17 is disposed on the outside of the photosensitive drum 1 so that the photoconductive layer faces, and this drum 17 is rotated counterclockwise in synchronization with the document table 61 and the photosensitive layer 56. It is arranged so that it can rotate in the direction.

In addition, around the outside of the drum 17, there is a screen charger 28 and a screen charger 28 for removing charges remaining on the photosensitive screen drum 17, which is made of an ET, (electroluminescence) plate or an AC corona charger. 6
9, and a charged particle source (corona discharger) 19 that projects charged particles to a position facing the photoreceptor 1 inside the photosensitive screen drum 17.

A portion of the photosensitive screen 17 is shown in FIGS. 5A and 6.
As shown in Figure A, a conductive screen 11 made of stainless steel or the like has a large number of fine openings 10 and has one side exposed;
An insulating layer 13 made of methacrylic resin or the like provided on the other side of the conductive screen, a conductive layer 14 for biasing such as AJ provided on this insulating layer by vapor deposition or the like, an azo dye,
The photoconductive layer 15 is made of selenium, amorphous silicon, cadmium sulfide, zinc oxide, or the like.

Note that the photosensitive screen 17 may have another structure, for example, it may have a layered structure as shown in FIG. 5B. Additionally, other known layer configurations may be employed, such as the conventional NP photosensitive screen of FIG. 5C.

FIG. 6 shows a process of selectively depositing charges on the photosensitive drum 1 using the photosensitive screen 17 to form a latent image. First, as shown in FIG. 6A, the photoconductive layer 15 is negatively charged over the entire photosensitive screen 17 by the charger 28, and then the negative charge is selected by image exposure 32 as shown in FIG. to disappear or decrease.

Next, as shown in FIG. 6C, when positive or negative ion particles are projected from the charged particle source 19 onto the photosensitive screen 17, the positive or negative ion particles pass through depending on the amount of negative charge on the screen 17. A predetermined amount is deposited in a predetermined pattern on the photosensitive layer 56 to form a desired electrostatic latent image. In addition, ■ in Figure 60 is a bias power supply, AC is an alternating current power supply for discharge, AC
, is an AC power supply.

FIG. 7 shows the relationship between the amount of negative ion particles passing through the surface of the photosensitive fleece 1F0, and the smaller the surface potential (negative), the more the amount of ions passing through the photoreceptor drum 1.
This results in an increase in the number of negative ion particles that reach . Also,
FIG. 8 shows the relationship between the amount of positive ion particles passing through the surface potential of the photosensitive screen 17 and the larger the surface potential (negative), the more the amount of ions passing through the photosensitive drum 17.
This results in an increase in the number of positive ion particles that reach .

Although the present invention has been illustrated above, the embodiments described above can be further modified based on the technical idea of the present invention.

For example, in addition to the blue-yellow combinations mentioned above, the combinations of colored lights irradiated on the photosensitive drum and the photosensitive screen include red-yellow, red-yellow,
Various colors can be used, such as magenta-cyan, i-blue, red-white (white light), and magenta-white (white light).
If it is not possible to obtain two colored lights using a dichroic mirror, the optical path may be separated using a half mirror and a color filter may be inserted into each optical path. Also,
When irradiating the photosensitive drum and the photosensitive screen with cyan and red chromatic light, respective color filters may be used in place of the above-mentioned dichroic mirror. In addition, electrostatic charge images on the photoreceptor drum and photosensitive screen,
The polarity of the ionic particles may be reversed from that in the example described above.

As shown in Figure 9, NP, which is known as a photosensitive screen,
When a photoreceptor is used, positive ion particles and negative ion particles are selectively passed through depending on the light irradiation area on the screen, and combined with the electrostatic charge image (not shown) on the photoreceptor drum 1 in the same manner as described above. can do. Further, three or more types of image information to be combined may be used, and the optical means may be variously changed for this purpose.

F. Effects of the Invention As described above, the present invention uses the positive first electrostatic charge image formed on the image carrier as the first image information, and each positive and negative ion flow passes through the ion flow control screen. is used as the second image information, and these image information are combined to separate the latent image potential of chromatic color from the potential level of achromatic color. can be formed. Therefore,
A desired image can be reproduced clearly, with high precision, and with easy control.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1, FIG. 2, and FIG. 3 are process diagrams during image formation by each side, FIG. 4 is a schematic sectional view of the image forming apparatus, and FIG. Figures 5A, 5B, and 5C are enlarged sectional views of a portion of the photosensitive screen; Figures 6A, 6B, and 6C are process diagrams of an image forming process using the photosensitive screen; and Figure 7. , FIG. 8 is a graph showing the amount of ions passing through the screen depending on the surface potential of the photosensitive screen, and FIG. 9 is a step diagram of an image forming process using another photosensitive screen. In addition, in the symbols shown in the drawings, 1................................................................... Photosensitive drum 17......・・・Photosensitive screen 19・・・・・・・・・・・・・・・・・・
・Charged particle source 44...
・Original image or manuscript 47・・・・・・・・・・・・
・・・・・・Dichroic mirror 56・・・・・・
...... Photosensitive layer AC, AC2...
・・・AC′power supply■・・・・・・・・・・・・・・・・・・
...Bias voltage. Agent Patent Attorney Hiroshi Aisaka 7φ Ken 11nllHE! Ba)

Claims (1)

[Claims] 1. When obtaining a plurality of image information from the original image and synthesizing these image information to separate the chromatic latent image potential from the achromatic potential level, the positive first electrostatic charge formed on the image carrier The image is used as first image information, and each positive polarity and negative polarity ion flow that selectively passes through this ion flow control screen according to a second electrostatic charge image formed on the ion flow control screen is used as a second image. An image forming method characterized by forming an image as information.