JPS6032190B2 - Two-color recording method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a two-color recording method.

Recently, after a light-conducting photoreceptor is charged, the surface of the photoreceptor is scanned with one-dimensional light to form an electrostatic latent image on the photoreceptor corresponding to the image signal to be recorded. A recording method that visualizes images has come into practical use.

An object of the present invention is to provide a recording method that takes such a recording method one step further and allows recording to be performed in two colors.

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

FIG. 1 schematically shows a two-color recording process which is the principle of the present invention.

In the figure, reference numeral 1 indicates a photoreceptor; photoreceptor 1
has a three-layer structure in which a first photoconductive layer 11 and a second photoconductive layer 12 are layered in this order on a conductive substrate 10.

The photoconductive layer 11 is selected from its spectral sensitivity to be sensitive to chromatic color A light and not sensitive to chromatic color B light.

Contrary to the photoconductive layer 11, the photoconductive layer 12 is selected to have sensitivity to chromatic color B light and not to chromatic color A light. The photoreceptor 1 is first uniformly charged by the charger 2 under uniform exposure to chromatic color A light, that is, color A light.

Since the photoconductive layer 12 is not sensitive to A-color light, it does not lose its electrical insulation even when exposed to A-color light, and the charge given by the charger 2 (herein explained as negative polarity) is , the surface of the photoreceptor 1 is charged, and positive charges are induced and uniformly distributed at the interface between the photoconductive layers 11 and 12 (FIG. 1). This charging process is called primary charging. Note that the 11th order charging may be performed on the floor. However, it is possible to achieve the desired purpose in a shorter time by performing exposure with A color light. That is, in this case, the photoconductive layer 11 is made conductive by the A color light transmitted through the photoconductive layer 12, so that positive charges are easily induced in the lower part of the photoconductive layer 12. Now, the photoreceptor 1 charged in this way is subjected to secondary charging by the charger 3 in the floor (FIG. 10).

The polarity of this secondary charge is opposite to that of the primary charge, that is,
In the case currently being described, the polarity is positive, and it is carried out so that the following conditions are satisfied. That is, the positive charge applied to the photoreceptor 1 by the charger 3 gradually cancels out the negative charge applied to the photoreceptor 1 due to the primary charging, but in this process, the photoreceptor surface potential changes with respect to the photoreceptor surface potential. The contribution of the negative charges in the photoconductive layer 12 gradually becomes smaller, and the contribution of the positive charges in the lower part of the photoconductive layer 12 becomes relatively large. Therefore, the surface potential of the photoreceptor 1 is initially negative, but as the secondary charging continues, the absolute value of the potential gradually decreases, and finally the surface potential of the photoreceptor becomes approximately zero potential.
Secondary charging occurs when the surface potential of the photoreceptor becomes approximately 0 potential.
will be stopped.

The fact that the potential on the surface of the photoreceptor is 0 means that the potential due to negative charges on the front side of the photoconductive layer 12 and the potential due to positive charges on the back side cancel each other out. Therefore,
In this state, sufficient negative charges due to the primary charging still remain on the surface of the photoconductive layer 12. Next, one-dimensional optical scanning is performed on the photoreceptor 1 whose surface potential has become approximately 0 (FIG. 1m). That is, depending on the image signal Q, A
One-dimensional light scanning using colored light is performed, and one-dimensional light scanning using B color light is performed in accordance with image signal B. Then, in these one-dimensional light scans, the photoconductive layer 11 becomes conductive in the photoreceptor portion exposed to the A color light, and a portion of the positive charge on the back surface of the photoconductive layer 12 escapes to the conductive substrate 10.
The remaining positive charge balances the negative charge on the photoreceptor surface.

As a result, the contribution to the photoreceptor surface potential is once again dominated by negative charges, and the surface potential of the photoreceptor portion becomes negative again. On the other hand, in the photoreceptor portion exposed to B color light, the photoconductive layer 12 becomes conductive;
The negative charges on the surface of the photoreceptor move through the photoconductive layer 12 and are neutralized with some of the positive charges on the back surface of the photoconductive layer 12 .

As a result, the contribution to the photoreceptor surface potential is the same as that of the photoconductive layer 12.
The residual positive charge on the back surface becomes dominant, and the surface potential of the photoreceptor portion becomes positive. Of course, the surface potential of the unexposed portion of the photoreceptor is approximately OV.
In this way, a static latent image corresponding to the image signal Q is formed on the photoreceptor 1 by a surface potential distribution of negative polarity, and a static latent image corresponding to the image signal 3 is formed by a surface potential distribution of positive polarity. be done.

In this way, the positive polarity portion of the electrostatic latent image formed is colored B, and the negatively charged toner TB
Also, the negative polarity part is colored A and visualized by the positively charged toner T^ (
Figure 1 W).

Thus, the information of the image signal Q is expressed as a visible image of color A.
The information of the image signal 8 is reproduced on the photoreceptor 1 as a B color visible image.

In this way, the visible image obtained on the photoreceptor 1 is fixed on the photoreceptor 1 as it is (if the photoreceptor 1 is in the form of a sheet), or is transferred onto a suitable recording sheet. Later, it is fixed on this recording sheet.

In this way, the information of the image signals Q and 8 is recorded as three signals A and Ba. It goes without saying that the above information can be recorded in any two colors by changing the combination of toner colors.
FIG. 2 shows, as a model, the changes in the position of the blades on the photoreceptor surface leading to the formation of a static latent image.

Curve 2-1 shows the change in surface potential of the photoreceptor part that is one-dimensionally scanned with A-color light, and curve 2-2 shows the change in surface potential of the photoreceptor part that is one-dimensionally scanned with B-color light. . FIG. 3 shows an example of a one-dimensional optical scanning method for implementing the present invention.

That is, in the figure, numerals 31 and 32 are Caesar light sources, numerals 33 and 34 are modulators, numeral 35 is a reflecting mirror, numeral 36 is a dichroic mirror, numeral 37 is a beam expander, numeral 38 is a rotating polygon mirror, Reference numeral 39 indicates a lens 8, and reference numeral 40 indicates a photoreceptor. The laser light sources 31 and 32 respectively emit a laser beam L^ of color A and a laser beam LB of color B.

It goes without saying that the first and second photoconductive layers in the photoreceptor 40 are selected depending on the colors A and B of the laser beams L^ and LB. The modulation devices 33 and 34 are applied with image signals Q and 8 from the outside, respectively, and intensity-modulate the incident laser beams L^ and LB according to the image signals Q and 8. Specific examples of the modulation devices 33 and 34 include an AO modulation element, an Eq modulation element, and a tuning element. The laser beam whose intensity is modulated according to the image signal Q is reflected by the reflecting mirror 35.
After being reflected by, the light enters the dichroic mirror 36. The laser beam LB whose intensity is modulated according to the image signal 8 is incident on the dichroic mirror 36 .

The dichroic mirror 36 has 10
The spectral reflectance characteristics are adjusted so that it has a transmittance of nearly 0% and a reflectance of nearly 100% for B color light.

Therefore, the laser beam LB passes through the dichroic mirror 36 and mixes with the laser beam L8 reflected by the dichroic mirror 36.

After the beam diameter of the mixed beam is expanded by a beam expander 37, the beam enters a rotating polygon mirror 38 that rotates at high speed in the direction of the arrow. be deflected.

The mixed beam reflected by the rotating polygon mirror 38 enters the N-8 lens system 39, and is focused on the circumferential surface of the photoreceptor 40 by the focusing action of the lens system.

The photoreceptor 40 is formed in the shape of a drum, and its circumferential surface is moved cyclically. After being subjected to primary and secondary charging by a pair of chargers (not shown), the circumferential surface is transferred to an optical scanning section. reach. "-8 lens system 39,
In the optical scanning section, the east concentration point of the mixed beam is moved periodically in a fixed direction at a constant speed on the circumferential surface of the photoreceptor in the direction of rotation of the photoreceptor 40, and the photoreceptor 1 is moved at a uniform speed. Laser beams L^, L, which are components of a mixed beam, perform dimensional light scanning.
Since B is intensity-modulated according to the image signals Q and 8, the static box latent images corresponding to the image signals Q and 8 have potential distributions with mutually opposite polarities due to the repetition of one-dimensional optical scanning. A photoreceptor 40 is then formed. The electrostatic tank image formed is
The image is visualized using two types of toner that are charged with opposite polarities and colored in different colors, and the resulting two-color visible image is transferred onto a recording sheet and then fixed on the recording sheet. . As described above, according to the present invention, a two-color recording method can be provided.

In the above explanation, a method of performing one-dimensional optical scanning using a laser beam was taken as an example, but methods of performing one-dimensional optical scanning are not limited to methods using a laser, but also methods using a light emitting diode array or a CRT. Various methods are possible.

The photoreceptor used in the present invention may also include one in which a dielectric thin layer or rectifying layer is interposed between the conductive substrate and the first photoconductive layer, or one in which a dielectric thin layer or rectifying layer is provided on the surface of the photoreceptor. The use of an overcoated layer is effective in improving image contrast, especially contrast, in recorded images.

[Brief explanation of the drawing]

1 and 2 are diagrams for explaining the two-color recording method according to the present invention, and FIG. 3 is a diagram for explaining the two-color recording method according to the present invention.
FIG. 2 is a plan view showing an example of a dimensional optical scanning method. 1... Photoreceptor, 10... Conductive substrate,
11...First photoconductive layer, 12...Second photoconductive layer, 31, 32...Laser light source, 33
, 34...Modulation diamond counterfeit, 35...Reflector, 36...Dichroitsukumifu, 38...
・Rotating polygon mirror, 40... photoreceptor. Son-in-law 1 figure Tokou 2 figures Pig 5 figures

Claims (1)

[Claims] 1. At least a first photoconductive layer sensitive to chromatic color A light and insensitive to chromatic color B light on a conductive substrate; A photoreceptor formed by laminating in the above order a second photoconductive layer that is sensitive to light of color B and insensitive to light of chromatic color A, in the dark or exposed to light of chromatic color A. The photoreceptor is firstly charged to a predetermined polarity under uniform exposure, and then secondarily charged in the dark with a polarity opposite to the first charge to bring the surface potential of the photoreceptor to approximately zero potential. One-dimensional light scanning with chromatic color A light is performed in accordance with image signal α, one-dimensional light scanning with chromatic color B light is performed in accordance with image signal β, and a latent image portion corresponding to image signal α is and a latent image portion corresponding to the image signal β, forming an electrostatic latent image in which the polarity of the photoreceptor surface potential is opposite to each other,
A two-color recording method characterized in that this electrostatic latent image is developed with two types of toners charged with opposite polarities and colored in mutually different colors. 2. A two-color recording method according to claim 1, characterized in that a photoreceptor is used in which a dielectric thin layer or rectifying layer is provided between the conductive substrate and the first photoconductive layer. . 3. A two-color recording method according to claim 1, characterized in that a photoreceptor having a second photoconductive layer overcoated with a dielectric thin layer is used.