JPS6025770A - Gradation recording method - Google Patents

Abstract

PURPOSE:To enable gradation recording by bringing the surface charge of an electrostatic latent image to a dot diameter according to a beam length by coulomb repelling force, by controlling the beam length corresponding to a gradation signal by using beam finer than a recorded dot pitch in ion beam for forming the electrostatic latent image. CONSTITUTION:Ion beam 9 generated in a corona ion generator 1 is accelerated by a converging electrode 2 while a beam diameter is throttled and an electric field in a forward direction is applied to a beam length control electrode 3 in a pulse form to control the length of beam passing through said electric field. When ion beam reaches the surface of a dielectric body 7 to which a latent image is formed, each ion expands by coulomb force. Therefore, ion quantity increases as the beam length is extended and the spot diameter thereof becomes large. By utilizing this theory, image density can be expressed by the length of beam.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gradation recording method for obtaining high quality gradation images with a simple mechanism.

Conventionally, this type of method uses an electrophotographic, 9-electro recording, inkjet, or thermal type device to sequentially fill in a matrix of about 2 x 2 to 8 x 8 to create gradations. This was achieved using a dithering method, a method of varying the density of each recording dot in several stages, or a combination of these methods, resulting in a decrease in resolution due to the creation of a matrix, the appearance of moiré, stepped edges, or the dot unit. There were drawbacks such as the intervention of unstable elements in controlling the shading of the image, and the lack of two gradation levels.

On the other hand, according to the method of electrostatic recording by controlling the ion flow, the diameter of the recording dot can in principle be changed steplessly.
It is flu B that the control port WVr becomes ・i1 coarser and the number of gradation steps is increased. There was a drawback that the concentration of the liquid tends to be non-uniform.

In order to eliminate these drawbacks, this invention aims to improve the time width for the ion flow to pass through the control electrode without changing the ion flux diameter at the control electrode section in a method of recording quietly by controlling the ion flow. By changing the recording dot diameter, the recording dot diameter is controlled and a gradation image is obtained. A detailed description of the invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of this invention, in which 1 is a column p'j-
f-on generator, 2 is an ion flow focusing electrode, 3 is an ion flow control electrode, 4 is a control pulse for passing the ion flow, 5,
6 is a voltage generation source, 7 is a dielectric recording medium, 8 is a conductive substrate,
9 is the trajectory of the ion flow (see Japanese Patent Application No. 57-11917 for details of the above superposition configuration).

This is used to form an electrostatic latent image, and 5Vc narrows down the flux diameter of the corona ion flow generated in the corona ion generator 1 with the 4 poles 2 for ion focusing, and further directs the ion flow control electrode 3 in the forward direction. By applying a pulsed electric field in the direction (direction in which the corona ion flow advances toward the recording medium), the corona ion flow is allowed to pass only during the pulse time width T, and by changing the dielectric constant T, the dot diameter of the electrostatic latent image can be changed. can be changed.

Figures 2 (a), (b), and (c) schematically represent the dot diameter of the electrostatic latent image increasing as the control pulse width T increases, 10 is the surface charge, 11゜1
2.13 is a dot-shaped electrostatic latent image.

When the control pulse width T is short, the ion flow travels almost straight and forms an electrostatic latent image 11 of small dots (Fig. 2(a)).
However, once surface charges are formed on the dielectric recording medium 1,
This surface charge changes the electric field near the surface of the dielectric recording medium, and the next ion stream's trajectory is bent outward from the center of the surface charge due to the Kujin repulsion of the surface charge, causing the surface to fall outside of the existing charge dots. Forms a charge (Fig. 2 (
b).

(C)). This happens continuously, and as a result, the dot diameter of the electrostatic latent image increases as the control pulse width increases.

Figure 3 shows the relationship between the control pulse width T (minimum pulse @To, which makes it dimensionless) and the area S of the electrostatic latent image formed at that time (the cross-sectional area of the initial ion flow, S, which makes it dimensionless). The area of the dot increases approximately in proportion to the control pulse width TK.

0 M4 diagram is a diagram showing an example in which the trajectory of the ion flow is bent according to the electric field formed by the surface charge on the dielectric recording medium T, -14 is the equipotential surface, and 9 is the trajectory of the ion flow, that is, Here, they correspond to electric lines of force.

For example, the trajectory 9 of the flow of the dielectric recording medium is determined by the surface charge 10 so as to be orthogonal thereto, as shown in the figure.

In this gradation recording method, it is effective to increase the current density by narrowing down the diameter of the initial ion flux passing through the control electrode as much as possible. It is desirable to narrow down the ion flux diameter in the ion flow control electrode 3. Generally, the electric field strength E, ~E4 of each part in Fig. 1 is set to E when the control pulse is applied.
l<E, .

It is better to set it so that E, < E4 (, - For example, E
, two F2: E3: E4=l: 2: 4
Although the ion flow can be well focused using an electric field ratio of :8, other electric field ratios may be used. Further, although it is effective if the ion flow focusing electrode 2 is used for focusing the ion flow, it is not necessary. Recording dot pitch 1
In order to obtain the number of gradations N when it is mm, it is sufficient to set it to the lower side.

In this method, for example, a dot pitch of 10 dots/m
If the ion flux diameter is set to 20 μm and 8 degrees, and the maximum dot diameter is 100 μm and the minimum dot diameter is 25 μm, the dot area can be set at equal intervals in 16 steps from 0.

At this time, if the ion flow density is set sufficiently large, the minimum control pulse width is T. = 0.6 n18ee, maximum pulse width is set to about 10 m5ec, l Omm7'se
c It can correspond to the recording speed of Jfill.

FIG. 5 shows an embodiment of an apparatus for realizing the gradation recording method of the present invention, in which 15 is a developing device, 16 is a recording sheet, 17 is a feed roller, 18 is a transfer device, 111 is a fixing device, and 20 is a residual Charge eraser, 21 is a lightning drum, 22 is an electrostatic latent image,
23 is a toner surface, 24 is a final image after fixing, 25 is a residual charge, and 26 is a 1n sweeper.

In order to operate this, corona ions generated by the corona ion generator 1 are passed through the ion flow control electrode 3 in accordance with the control pulse 4 to form an electrostatic latent image 22 formed on the dielectric drum 21 in the developing device 15. The charged toner is supplied and adhered to the recording paper 16 by the transfer device 1B, and then transferred to the recording paper 16 by the fixing device 19.
A final image 24 is obtained. Dielectric drum 2
The residual charge 25 remaining on the image forming apparatus 1 is erased by a residual charge eraser 20, and the residual toner is removed by a cleaner 26, thereby completing the process and preparing for the next electrostatic latent image wave.

Note that the ions may be generated by a corona ion generator 1 or less.

As explained above, the present invention is a gradation recording method that changes the recording dot diameter by changing only the control pulse width, so the control circuit is simple and the number of gradations is large.
Moreover, it has the advantage that it is easy to maintain uniformity of dot density.

[Brief explanation of the drawing]

Fig. 1 is a structural JR diagram showing one implementation of this invention, and Fig. 2 (a
), (b), and (c) are operation explanatory diagrams of this invention, Part 3.
4 is a diagram showing operation data of the present invention, FIG. 4 is a detailed explanatory diagram of the present invention, and FIG. 5 is an overall diagram of an embodiment of a recording apparatus using the present invention. In the figure, 1 is a corona ion generator, 2 is an ion flow focusing electrode, 3 is an ion flow control electrode, 4 is a control nozzle, 5, 6
1 is a voltage generation source, 1 is a dielectric recording medium, 8 is a conductive substrate, 9
is the trajectory of the ion flow, 10 is the convergent charge, 11, 12.13
14 is an electrostatic G image, 14 is an equipotential surface, 15 is a developing device, 16 is a recording paper, 17 is a feed roller, 18 is a transfer device, 19 is a fixing device, 20j is a residual charge eraser, 21 is a dielectric drum, 2
2 is an electrostatic latent image, 23 is a toner image, 24 is a final image, 25
is a residual charge, and 26 is a cleaning device. Fig. 1 Fig. 2 (a) ' (b) (c) Fig. 3 Control pulse radiance T. - Figure 4

Claims (1)

[Claims] In this method of recording by controlling the flow of generated ions and forming an electrostatic latent image on a dielectric material, an ion flux with a diameter smaller than that of recording dot pinch is used, and the ion flow irradiation time for each dot is shortened. As the ion flow irradiation amount for one dot increases, the dot diameter of the electrostatic latent image increases due to the Coulomb repulsion force of the surface charge of the electrostatic latent image. A gradation recording method characterized by changing the gradation.