JPS61185456A - Electrostatic recording system - Google Patents

Abstract

PURPOSE:To obtain an electrostatic recording system capable of forming unform latent images and free of dispersion of dot sizes by utilizing a discharge circuit ten times or more. CONSTITUTION:An alternate voltage of 3MHz is applied between elelctrodes 11 and 12 to form dot latent images on a recording material moving at a speed of 12 inch/sec. Since 16 electrodes 11 and provided and a dot latent image density of 300 dots/in. is conditioned, the time taken to write in one dot is 1/300X12X16=17.4mus, and the time taken for rising of discharge voltage is about 2 mus, and also for trailing of the voltage is about 8mus. The time interval during the period when effective voltage occurs is 7.3mus. Since the frequency of alternate voltage is 3MHz, the peaks of 3X7.4X2=44 times are produced. Negative ions, however, are all adsorbed on the surface of a dielectric material 14, and discharge times to be utilized for obtaining one dot latent image are 22 times. By utilizing discharge of 10 times or more, dot latent images free of dispersion of sizes can be obtained.

Description

[Detailed description of the invention] 1 yen beans The present invention relates to an electrostatic recording method.

1. In electrostatic printing, generating ions with high current density, extracting the ions, and selectively applying them to a charged member to charge the member in an image-like manner is disclosed in, for example, the US patent. Fourth
It is known from Publication No. 155093. This device
In an ion generator including a 14-layer body, a plurality of first electrodes fixed to one side of the dielectric body and extending in a first direction, and a plurality of first electrodes fixed to one side of the dielectric body and a plurality of first electrodes fixed to the side of The plurality of first electrodes and the plurality of second electrodes constitute a matrix.

By applying an alternating voltage between the first electrode and the second electrode corresponding to a selected portion of this matrix, negative ions are generated in the vicinity of the second electrode facing the selected portion. The generated ions can be selectively extracted to charge the member to be charged. Therefore, electrostatic recording using dots can be performed by selectively driving the matrix-structured electrodes.

Is static recording using this method considered to be useful?The currently known method has the disadvantage that the size of each dot recorded is not constant and varies, which makes it impossible to form a uniform latent image. There is a problem.

Accordingly, the present invention aims to elucidate the cause of the variation in dot size in the electrostatic recording method described above, eliminate this, and make it possible to form dots of uniform size. An object of the present invention is to provide an electrostatic recording method that can form a uniform latent image.

1151" The present inventor has provided a plurality of first electrodes extending in a first direction,
a second electrode extending in a second direction different from the first direction and forming a matrix together with the first electrode; a third electrode having an opening; a first dielectric between the first and second electrodes; and a second dielectric between the second and third electrodes; The body has an opening corresponding to the matrix, and an alternating voltage is applied between the first electrode and the second electrode, and ions are generated by discharge between the second electrode and the first dielectric surface. In an electrostatic recording method in which ions are drawn out from an opening of the third electrode by a potential difference between the second electrode and the third electrode, and the ions form a charge pattern of charge dots on the surface of the recording medium, the cause of non-uniformity in dot size can be solved. By elucidating this and increasing the number of effective ion generation times to 10 or more when forming one 'lk-loaded dot, it was possible to make the dot size uniform and, therefore, to form a uniform latent image.

1 example of tip j FIG. 1 is a sectional view of an electrostatic recording head used in the electrostatic recording method of the present invention, and FIG. 2 is a perspective view thereof.

Rad 1 for this electrostatic recording is in the horizontal direction (first direction) in Figure 1.
A first electrode 11 is an induction electrode extending in a direction, and a second electrode 12 is a discharge electrode extending in a second direction that is different from the first direction.
When viewed from above in FIG. 1, these electrodes constitute a matrix. Second electrode 12
There is a third electrode 13 on the opposite side of the first electrode 11, which has a plurality of openings corresponding to seven trixes. A first electrode 11, a second electrode 12, and a first dielectric 14 are sandwiched between them. That is, the first electrode 11 and the second electrode 12 are fixed to respective surfaces of the first dielectric 14. Second electrode 1
The second and third electrodes 13 also sandwich a second dielectric 15 between them. The second dielectric 15 has openings 16 corresponding to the plurality of openings of the third electrode 13. By selectively applying alternating voltages between the plurality of first electrodes 11 and second electrodes 12 of the ion generator having this configuration, positive voltage is applied to the vicinity of the second electrodes 12 corresponding to the selected portions of the matrix.・Negative ions are generated. A bias voltage is applied between the second electrode 12 and the third electrode 13, and only ions of polarity determined by the polarity are extracted from the positive and negative ions, and these ions pass through the apertures 16 and 17. A charged member, which is a recording material (not shown), provided opposite to the opening 17 is charged. In this way, the plurality of first electrodes 11 and second electrodes 12
A dot latent image can be formed on the recording material by selectively driving the dots.

Before explaining the electrostatic recording method of the present invention using this recording head, the causes of dot/dot size variations that have been elucidated by the inventor of the present invention will be explained in detail. FIG. 3 shows temporal changes in the current flowing between the first electrode 11 and the second electrode 12. In FIG.

The sharp spike-like current that occurs multiple times (typically twice) during one cycle is due to the discharge that generates positive and negative ions. This discharge is strong 1. It is thought that radiation occurs in a place where there is an electric field, and the point at which the discharge occurs is random and not constant. If the discharge current waveform is repeated many times, it will appear as shown in Figure 3. become,
It is understood that the timing of discharge occurrence varies widely.

The inventor believes that since the time point at which the discharge occurs is different from cycle to cycle, the discharge voltage is different.

It was thought that the number of ions extracted and passing through the aperture 17 would be different every time, and that this would be an obstacle to obtaining a non-uniform dot latent image. In order to eliminate this non-uniformity, instead of creating dots with one large discharge, it is conceivable to reduce the amount of discharge per discharge and generate ions multiple times per dot. The inventor repeated experiments on reducing the discharge and increasing the number of times, and found that by increasing the number of discharges to 10 times or more, the variation in dot diameter was significantly reduced.

The electrostatic recording method of the present invention will be explained below.

In FIG. 1, an alternating voltage with a frequency of 3 MHz is applied between the first electrode 11 and the second electrode 12, and a charged member (not shown), which is a recording medium, is connected to the third electrode 13 below the recording head. They are placed opposite each other. This charged member is 1
Moves at 2 inches/second. The first electrode 11 is a 16-meter electrode, and the above-mentioned alternating current voltage is applied to each part of the electrode 11 sequentially in time division.In this embodiment, the dot latent image density is 300.
Since the dot is closed, the time required to write one dot is l/(300X12X16)=1
It is 7.4gs.

On the other hand, when the alternating voltage signal is applied between the first electrode 11 and the second electrode 12, the dischargeable voltage is not reached at the same time, but it takes a predetermined time Tr for the voltage to rise as shown in FIG. Similarly, Tf is required for the falling edge. The switching time Tr is approximately 2 ps, and the switching time Tf is approximately 8 JLS. Therefore, the time interval during which effective discharge occurs is 17.4
-2-8 = 7.4tS. Since the frequency of the AC TL voltage is 3MHz as mentioned above, the peak of the alternating voltage is 3 x 7.4 if positive and negative are included in this 7.4 gs.
X2 = occurs 44 times. However, among the two peaks within one period, the discharge when the first electrode 11 has a positive voltage with respect to the third electrode 13 does not contribute to latent image formation, and FIGS. 6 and 7 show such a situation. F′:pIl electrode 11
is relative to the third electrode 13 (te+100OV c7)
Fig. 6) and -1000V maki (Fig. 7) are shown. In the case of FIG. 6, it is understood that all the negative ions generated in the discharge generation area are absorbed on the surface of the first dielectric 14 and do not flow downward. Therefore, the number of radiations available to obtain one image of one dora) is 44/
2=22 times. In this way, by using 10 or more discharges to form a one-ton latent image, a 1. Ma the latent image! ↓Every step A(?
'In order to make the number of Kisu ion occurrences more than 10 times per dot, the frequency f should be set to the relative moving speed of the recording medium, Vp,
The number of time divisions is n, the number of dots formed on the unit length dust of the recording medium is p, the time from the application of the alternating voltage amplitude until the generation of effective ions is Tr, and the generation of effective ions is stopped. When the time from when the amplitude of the alternating voltage reaches O is Tf, 10/ [1/ (Vp×n×p)-Tr-
This means that Tfl≦f is satisfied.

In this example, Vp=12i n,/s, n=1f3
,p=3oo dot/i
n, T r = 2 p-s
, T f =8g5, so the frequency f
satisfies f≧1.4MHz. On the other hand, the generated ions are transferred from the ion generating section to the opening 17 of the third electrode 13.
It has been found that it takes a certain amount of time for the ions to reach the aperture 17, and that if an alternating voltage with a faster frequency than this is applied, the ions do not reach the aperture 17. The reason for this is thought to be that the electric field switches between FIG. 6 and FIG. 7 too quickly and the ions are not accelerated downward. Therefore, the frequency is f≦
It is preferable to satisfy 1/T (T is the time required for ions generated near the second electrode 12 to reach the aperture 17).

According to experiments, the time T is approximately 0.21 Ls. Therefore, in this embodiment, the frequency is preferably 5 MHz or less.

In this example, since the frequency was set at 3 MHz, a uniform dot latent image was formed and a high-definition image was formed.

[9] As explained below, according to the present invention, it is possible to eliminate variations in dot diameter and form a uniform and high-definition latent image.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an electrostatic recording head used in the electrostatic recording method of the present invention, Fig. 2 is an exploded perspective view of the electrostatic recording head of Fig. 1, and Fig. 3 is a cross-sectional view of the electrostatic recording head used in the electrostatic recording method of the present invention. Figure 4 shows the current flowing between the first and second electrodes, which are temporally superimposed, and Figure 5 shows the alternating voltage generated between the first and second electrodes. The figure which shows the temporal change of. 6 and 7 are diagrams showing the appearance of electric lines of force in different states in the apparatus of FIG. 1. "LΩ" L man 11: 1st electrode 12: 2nd electrode 13: 3rd electrode 14: 1st dielectric figure 1 figure 2 figure 3 cause figure 4 figure M&6 figure figure 7

Claims (1)

[Claims] 1) a plurality of first electrodes extending in a first direction, a second electrode extending in a second direction different from the first direction and forming a matrix together with the first electrodes; a third electrode provided on the opposite side of the two electrodes from the first electrode and having an opening corresponding to the matrix, a first dielectric between the first electrode and the second electrode, and the second electrode. and third
a second dielectric between the first electrode and the second dielectric, the second dielectric having an opening corresponding to the matrix;
An alternating voltage is applied between the electrodes, ions are generated by discharge between the second electrode and the first dielectric surface, and the ions are transferred to the opening of the third electrode due to the potential difference between the second and third electrodes. An electrostatic recording method in which a charge pattern of charge dots is formed on the surface of a recording medium using the ions, the method comprising: forming an effective ion generation number of 10 or more when forming one charge dot; Electrographic method. 2) In the electrostatic recording method according to claim 1, the relative moving speed of the recording body is Vp, the number of time divisions is n, and the number of dots formed per unit length of the recording body is p.
, where Tr is the time from when the amplitude of the alternating voltage is applied until effective ions are generated, and Tf is the time from when the generation of effective ions stops until the amplitude of the alternating voltage becomes 0. The frequency of the voltage is 10/[1/(Vp×n×p)−
Tr-Tf] or more.