JPS587661A - Two color printer - Google Patents

Abstract

PURPOSE:To provide a device whicn can discriminate information abnormality by forming the surface potential of the polarity reversed from that of the 1st surface potential on a photoreceptor, and exposing the same at the quantity of light of ternary levels. CONSTITUTION:An electrostatic charger 2 and a lamp 3 are turned on simultaneously to charge an insulation layer 1c negatively. Since a photoconductive layer 1b is conducted for the purpose of full surface exposure, the positive charge from a conductive substrate is injected into the layer 1b and the positive charge distributes at the interface between the layer 1c and the layer 1b. The insulation layer is applied with the secondary charging of the polarity reversed from that of the primary charging by way of an electrostatic charger 4 so that the surface potential is inverted from negative potential to positive potential. A three-layered photoreceptor 1 of such a state is exposed by the information wherein the quantity of light has 3 stages of levels, whereby the positive and negative electrostatic latent images corresponding to black and red information are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a two-color printer, and more particularly to a two-color printer that is most suitable as an output terminal for office automation equipment.

Conventionally, there is a laser beam printer as a non-impact printer using electrophotographic technology and a laser. This method modulates laser light according to an information signal and further deflects it to form two-dimensional information on a recording medium in the form of pixel resolution, and then obtains a recorded image using the company's known electrophotographic process. In this case, since two-dimensional information is recorded in the form of pixel decomposition, it is easy to combine all information, delete information, or change the size of various characters.

However, since the recorded images are printed in the same color, it becomes difficult to identify the information.Furthermore, in the future, it will be difficult to distinguish between 47-o-mats and document information, or between additional information, supplementary information, etc. and main information. It is thought that such things will be strongly demanded.

SUMMARY OF THE INVENTION In consideration of the above points, it is an object of the present invention to provide a new two-color printer that is capable of identifying different types of information.

The present invention relates to a conductive support in a two-color printer.

A first layer is placed on a three-layer photoreceptor consisting of a photoconductive layer and a transparent insulating layer.
Charging is then carried out, or at the same time, the entire surface is exposed, followed by the first
A second charge is performed with a polarity opposite to the polarity of the band, and a surface potential with a polarity opposite to the first surface potential is formed on the photoreceptor, and a ternary level corresponding to three types of information is generated. Exposure to a light amount of , each with a positive potential.

It is characterized by forming an electrostatic latent image with approximately zero potential and negative potential, and developing both positive and negative potential portions corresponding to two-color information with charged particles of opposite polarity and different color, respectively.

Hereinafter, an embodiment will be described in detail using a red and black two-color print as an example.

FIG. 1 is a block diagram of a two-color printer of the present invention. The three-layer photoreceptor ■ has a conductive substrate (la) and a photoconductive layer (lb).
, and a transparent insulating layer (1c). First, the charger (2) and the lamp (3) are turned on at the same time, and the insulating layer (IC) is turned on.
is negatively charged. At this time, since the photoconductive layer (1b) is made conductive for the entire surface exposure, positive charges are injected into the photoconductive layer (1b) from the conductive substrate, and the positive charges are transferred to the insulating layer (1c).
) and the photoconductive layer (1b). Next, a charger (4) applies secondary charging with a polarity opposite to that of the primary charging, thereby inverting the surface potential from negative to positive.

The three-layer photoreceptor (1) in such a state is exposed to information having three levels of light intensity to form positive and negative electrostatic latent images corresponding to black and red information. At this time, the laser light source (6
) is converted into a light amount corresponding to each of the above levels through a deflector (
After being deflected by step 8), the three-layer photoreceptor (1) is scanned. Next, development is carried out using a developing device (9) using charged colored toners of opposite polarity (for example, black toner and red toner) with the developing bias set to #1 and zero, and the two-color image is transferred to the three-layer photoreceptor (1). ) to form on top.

After that, the polarity of the toner is aligned using a charger α,
A voltage opposite to that of the charger α1 is applied to the charger α9, and a two-color image is transferred onto recording paper (la), and is fixed by a fixing device (not shown) to obtain a two-color print.

On the other hand, the three-layer photoreceptor (1) is cleaned by passing through a static elimination stage (Q) and a cleaning stage (α) for repeated use.

Next, specific numerical values of the constituent elements in this example will be shown. A 60μm Ss photoconductive layer was formed on an AI conductive substrate, and a 60μm Mylar (trade name for polyethylene terephthalate) was formed on top of it to form a three-layer photoreceptor (1
). First, while applying -5KV to the charger 2, the entire surface is exposed to light with a light intensity of several tens of lux*sec.
A surface potential of 600v is created on the photoreceptor.

Next, by applying 16 KV to the charger (4),
Next, charging is performed to invert the surface potential to 300 to 400V. In this state, the black image area is several tens of e by AI+laser.
Expose at rg/Cd, and expose at several erg/Ctll for the white image area (+400 V for the red image area,
A surface potential of -300 V was formed on the photoreceptor in the black part (g11) and +50 V in the white part (g11). The photoreceptor in this state is developed with a developing device consisting of a positive polarity black toner and a negative polarity red toner with a bias potential of +50 V (= two images of red and black are obtained on the photoreceptor).

This was transferred onto plain paper using the known electrophotographic process ζ2 to obtain a two-color print.

Next, the latent image forming process will be described in detail with reference to the Wlz diagram. First, primary charging and full-surface exposure are performed simultaneously to negatively charge the transparent insulating layer (IC). At this time, light guide @M (lb
) is conductive for total ff1il light, positive charge is injected from the conductive substrate, and the transparent insulating layer (lc) and the photoconductive layer (1b
) A positive charge is retained at the interface with Next, secondary charging is performed with a polarity opposite to that of the primary charging, and the surface potential is reversed from negative to positive. By exposing the three-layer photoconductor (1) in this state to light quantities corresponding to black, red, and white, the photoconductive layer (1b) in the black image area becomes conductive, and the transparent insulating layer (1c) and photoconductive layer (1b) ) is discharged, leaving only the positive charges held by the negative charges on the transparent insulating layer (lc).

This results in a negative surface potential. On the other hand, since the light is off in the red image area, the surface potential at the time of secondary charging is maintained and remains at a positive potential. Furthermore, since the amount of light in the white image area is smaller than that in the black image area, the photoconductive layer (1b) becomes semi-conductive, and the positive @* of the interface between the transparent insulating layer (1c) and the photoconductive layer (1b) is the same. A partial discharge occurs, and the surface potential becomes approximately zero. As described above, the surface potentials of the black, red, and white image areas become negative, positive, and zero, respectively, and a two-color image; a corresponding electrostatic latent image is formed.

FIG. 3 shows the time course of the surface potential in the process in this case. In this way, positive potential and zero potential.

By forming negative potential levels, a p2 color image is obtained by performing ms with colored particles corresponding to each level.

Next, other embodiments will be described. In the above-mentioned embodiment, exposure is performed with a light amount corresponding to a two-color image after the secondary charging, but in this case, the charger (4) is improved in the same way as the charger (2), and the secondary charging simultaneous image is There is no difference in exposure. Furthermore, in the above embodiment, the photoconductive layer (lb) is S.
Considering the system, the primary charge was set to be negative. However, this is also CdS as photoconductive Jm (lb).

If OPC or the like is selected, the primary charge can be made positive and the secondary charge can be made negative, and various photoconductive layers can be used.

That is, in one embodiment, the black image area was set to a positive latent image potential and the red image area was set to a negative latent image potential, but this is also positive when the red image area is strongly fogged and the black image area is not exposed.

A negative latent image potential can be reversed. This is because black image areas are overwhelmingly more numerous than red image areas in document information, so when a semiconductor laser is used as the laser light source (6), this is a great advantage in terms of longevity. Therefore, when combining format information and document information or additional information and main information, the color of the information to be emphasized can be freely selected by simply adjusting the amount of light. Also 7
A similar result can be obtained by exposing the redundant information or additional information as a negative film and then exposing it to a laser beam where ζ=document information or main information. Further, by changing the exposure amount, the potential of the white image area can be changed, and the potential contrast between the white image area, the red image area, and the black image area can be freely changed. As a result, the density of each color can be changed freely if the developing bias is selected to be approximately white.

Specific numerical values are also shown for this example.

A/4 A 4-μm thick Cd5-CdSe is coated on a conductive substrate, and 5 μm of Mylar (trade name of polyethylene terephthalate) is formed thereon to form a three-layer photoreceptor. First, apply +5KV from the charger (2) to form a surface potential of +500V on the photoreceptor. Next, apply -6KV to the charger (4).
While applying KV and performing secondary charging, a semiconductor laser (GaAJAs, 780 nm, 10 mW) is used! Perform 1N light. At this time, by exposing the red image area to several tens of rgA and the white image area to several eyg/cdt, the voltage is -400V for the black image*m and +30V for the red image area.
A surface potential of 0 V and -50 V was formed on the photoreceptor in the white image area. In this state, development was performed by applying a developing bias voltage of 150 V to a developing device consisting of a black toner of positive polarity and a red toner of negative polarity.

As a result, a clear two-color print was obtained on plain paper as in the previous example.

In this way, the two-color printer of the present invention can withstand various functional changes with simple operations such as adjusting the exposure amount.
Even if users are likely to request various functions in the future, it is possible to meet their requests without making major changes to the lead, making it ideal for office automation equipment.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the present invention, and FIG. 2 is a diagram of the electrostatic latent image forming process. i, a separate figure, and FIG. 3 is a time course diagram of the surface potential. 1... Photoreceptor, 2... Primary charger 4.
...Secondary charger 6...Laser light source 7...Modulator 8...Deflector 9...Developer
1o...Polarity control charger 11...Transfer charger
12... Record paper agent Patent attorney Noriyuki Chika (
(1 person) Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) Charging of sl on a three-layer photoreceptor consisting of a conductive support, a photoconductive layer and a transparent insulating layer, followed by or simultaneous C; whole surface exposure is carried out, followed by a second charge with a polarity opposite to the first charge polarity. 2 is charged to overwrite the photoreceptor; a surface potential of opposite polarity to the first surface potential is formed, and exposed with a ternary level of light intensity corresponding to three types of information, each of which has a positive potential, approximately A two-color printer 0 characterized in that it forms electrostatic latent images of zero potential and negative potential, and displays positive and negative image dedicated portions corresponding to two-color information with charged particles of opposite polarity and different colors, respectively.