JPS5841510B2 - Electron radiation image forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of obtaining radiographic images using highly insulating liquids that absorb radiation such as X-rays.

A conventional method for creating radiation images (hereinafter also referred to as X-ray images) using a highly insulating liquid that absorbs radiation such as X-rays (hereinafter simply referred to as X-rays) is disclosed in Japanese Patent Application Laid-Open No. 5'0-8779.
No. 3, JP-A-50-125694, JP-A-50-43
No. 7176 (US Pat. No. 3,873,833) and the like.

That is, as shown in Figure 1, by absorbing X-rays between a pair of electrodes 1 and 2 arranged almost parallel to each other with a gap, electrons and ions of positive polarity or ions of positive and negative polarity are generated. A highly insulating X-ray absorbing liquid 3 is filled, an insulating image receiving sheet 4 is placed in contact with one electrode in the X-ray absorbing liquid 3, and a voltage is applied between the electrodes 1 and 2. while irradiating X-rays from the X-ray source 51,
In this method, the insulating X-ray absorbing liquid 3 is ionized according to the amount of X-ray irradiation, and the supergroup electrons are ionized. and positive polarity ions, or positive and negative polarity ions are respectively connected to the corresponding electrodes 1 and 2.
side, and an electrostatic latent image is formed on the image receiving sheet 4.

The obtained electrostatic latent image is developed into a visible image by a known electrophotographic method.

In this method, the image receiving sheet 4 is exposed to the X-ray absorbing liquid 3.
Since the X-ray absorbing liquid 3 is operated by being immersed in the liquid, it is necessary that the resistance of the X-ray absorbing liquid 3 is sufficiently high in order to form an electrostatic latent image and retain the latent image. In order to maintain this, it is necessary that the X-ray absorbing liquid 3 does not have a volume resistivity of 1014 Ω-axis or more, so a low-resistance X-ray absorbing liquid cannot be used.

Furthermore, in order to increase sensitivity, it is desirable to use an X-ray absorbing liquid with strong X-ray absorption, but most X-ray absorbing liquids that exhibit strong X-ray absorption are unstable residual solvents that decompose due to light or heat. When the image receiving sheet 4 is immersed in the X-ray absorbing liquid 31, soluble impurities in the X-ray absorbing liquid 31 that have adhered to the image receiving sheet 4 may dissolve and cause abnormal discharge. It can happen.

In addition, in order to increase the absorption efficiency of X-rays, if one solid such as CB r 4 tC■■■3 is dissolved in the X-ray absorbing liquid 3,
When the image-receiving sheet 4 is taken out, the liquid that has adhered to one surface of the sheet dries and these solids precipitate, resulting in low resistance and disturbing the electrostatic latent image.

Furthermore, since the X-ray absorbing liquid 3 may come into contact with the outside air, it may receive various types of contamination from the outside air and become unstable.

Furthermore, since the image receiving sheet 4 is immersed in the X-ray absorbing liquid 3, impurities may be mixed in therein.

Further, since the image receiving sheet 4 is in a wet state, it is necessary not to dry it, and in that case, the latent image may disappear, or the X-ray absorbing liquid 3 may be mixed into the developer and deteriorate the developer.

In addition, the X-ray absorbing liquid 3 has various problems, such as the amount of liquid acid reduced when the image receiving sheet 4 is taken out and put in, which increases the amount used and poses a safety problem. There is.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide an electron radiation image forming method that can form an electrostatic latent image using a chamber completely enclosed with an X-ray absorbing liquid. It is something.

This will be explained in detail below using the drawings.

FIG. 2 shows a cross section of chamber A used in the present invention 1,
An electrode 7 with high X-ray transparency and an insulating film 8 are placed opposite each other at a certain distance (approximately parallel to each other) using an insulating spacer 9, and one part of the gap absorbs X-rays. liquid 1
0 is sealed so that there is no contact with the outside.

Here, if there is any bubble inside the chamber A, it will cause abnormal discharge, so special care must be taken to ensure that no bubbles remain when filling the X-ray absorbing liquid 10.

The insulating film 8 should be sufficiently thin and have guaranteed mechanical strength, such as a polyester film with a thickness of 25 μm, to prevent a decrease in resolution and also to prevent damage to the chamber A. This is desirable in order to reduce the number of bumps, and since this insulating film is particularly required to have flatness, it is necessary to select a film that has excellent flatness with few irregularities on the surface.

Spacer 9 is highly insulating and X-ray absorbing liquid 10
A plate material with a uniform thickness made of a material that does not melt is used, such as a Delrin plate with a thickness of about 1 mm.

The enclosed X-ray absorbing liquid 10 is a liquid substance that absorbs X-rays and emits electrons when irradiated with X-rays, and has a volume resistivity of 51012Ω-axis or more when not excited by X-rays. It is desirable to use it.

For example, C C14* C which is liquid at normal temperature and normal pressure
H2' 2? CH2Br■, CF■2C4■, C2
■-■5■, CHBr3, etc. can be used, and CBr4, CHI3,
It is desirable to dissolve e, Kr, etc.

In the example, 1 liter of CCV4 liquid was 5% by weight of CBr4.
0% dissolved.

When filling the X-ray absorbing liquid 10, it is necessary to pay sufficient attention not only to the presence of the above-mentioned air bubbles but also to prevent contamination of impurities such as charged particles and conductive particles.

Forming an X-ray image using the chamber N as described above is carried out according to the following procedure.

That is, the electrode 12 is placed on the insulating film 8 of the chamber A.
A high voltage is applied to the electrode 12 and the electrode 7 of the chamber person, and at the same time, the subject 13 placed on the electrode 7 side is irradiated with X-rays from the X-ray source 14 in front. An electrostatic latent image is formed on the insulating film 8 by field emission.

To explain this in detail, chamber A (when X-rays are irradiated, the X-ray absorbing liquid 10 in the chamber
The energy of this X-ray is absorbed and ion pairs are generated.

Ion pairs within this X-ray absorbing liquid 10 are moved by an electric field within the liquid 10.

Now, if we apply a high voltage of negative polarity to the electrode 121, then
Negative ions or electrons generated within the radiation absorbing liquid 10 move toward the electrode 7 and eventually recombine.

On the other hand, positive ions move to the inner surface of the insulating film 8,
The electric field strength in the tiny gap between the insulating film 8 and the electrode 12 is increased.

As a result, the electric field strength in the microgap in the region where the X-rays are irradiated into the chamber A increases, and discharge is enabled by field emission from the electrode 12, and an electrostatic latent image is formed on the outer surface of the insulating film 8 by 1 negative charge. is formed.

After the X-ray irradiation, the electrode 12 is grounded and removed from the chamber A while being short-circuited to the electrode 7.

Thereafter, the latent image formed on the outer surface of the insulating film 8 is developed using a positive polarity toner by a known electrophotographic development method.

Further, an insulating film such as paper or polyester film may be placed on this insulating film 8 and the image may be transferred from thereon by negative corona discharge.

The discharge in the microgap between the insulating film 8 and the electrode 12 is caused by the so-called modified Paschen's law 1, and the discharge is caused by field emission 1 in which the microgap length is about 6 μm or less.

In reality, the length of the microgap between the insulating film 8 and the electrode 12 can be considered to be about several μm.

In addition, in the discharge deposit area due to this field emission, the discharge breakdown strength in micro-gaps is constant regardless of the gap length.

For this reason, if the microgap length between the insulating lume 8 and the electrode 12 is 6 μm or less, even if there is some variation in the gap length, uniform and reproducible imaging is possible. is possible.

As shown in FIG. 4, if the insulating film 11 for latent image reception is interposed between the insulating film 8 of the chamber A and the electrode 12 and the same operation as described above is performed, the insulating film 8 and the insulating An electrostatic latent image can be formed on the latent image-receiving absolute film 11 by field emission between the electrostatic film 11 and the electrostatic film 11 -b≦.

At this time, if a substance such as a surfactant is coated on the surface of one of the insulation ratio films 8, 11, field emission can easily occur and a good image can be obtained.

Specific Example I The X-ray absorbing liquid 10 is a liquid in which 50% by weight of CBr4 is dissolved in CCl4, and the electrode 12 is an Al plate 43.
Lightly polished with 000 emery and left for a long time to a thickness of 1
11 was used.

Simultaneously with X-ray irradiation (-26K V electrical distance is applied to the electrode 12, X-ray irradiation is performed at a position 1 m from the radiation source at an X-ray tube voltage of 75K).
When a resolution chart was photographed with Vp, tube current of 50 mA, and irradiation time Q of 1 sec, a good image was obtained.

Specific Example 2 A liquid in which 50% by weight of CB r4 was dissolved in C14 was used as the X-ray absorbing liquid 10, and a Nesa electrode was used as the electrode 12.

Then, at the same time as the X-ray irradiation (+24 V voltage is applied to the electrode 12, the X-ray tube voltage is 7.
5, a good image was obtained when an A1 level difference of 20 nm was photographed with a Vp1 tube current of 50 m and a heat radiation time of 0.2 sec.

The liquid developing toner used had a thickness of 100 μm.
1 to 30% was used, which gave a transmission density of about 1 at a potential of +25 V on the surface of the Mylar film.

Since the present invention is configured as described above, it has the following excellent advantages.

First of all, since the X-ray absorbing liquid 10 is completely sealed, it never comes into contact with the outside air, so it can be used stably for a long time without getting mixed with dust or contaminants. Even toxic X-ray absorbing liquids can be safely used.

First, it is not necessary to immerse the insulating film for receiving a latent image in the X-ray absorbing liquid 10, and the contamination of impurities, which has been a serious problem in the conventional method, can be solved.

Third, since a latent image is formed on the outer surface of the insulating film 8 outside the chamber A, the electrical volume resistivity of the X-ray absorbing liquid 10 can be reduced to 1012Ω-sore even if it has a low resistivity. It becomes possible.

Fourth, since electrostatic latent image formation is completely dry,
In the conventional method, the latent image does not disappear while the X-ray absorbing liquid 10 is being dried, or the X-ray absorbing liquid 10 is not mixed into the developer, causing deterioration of the developer.

Fifth (here, a charge pattern with the opposite polarity to the charge pattern inside the chamber A is formed on the outer surface of the insulating film 8 by field emission from the electrode 12 according to the charge pattern inside the chamber A, and then the electrode 7゜12 Insulating film 8 or insulating film 11 is grounded and peeled off.
Since a developable charge pattern is formed on the surface to form an electrostatic latent image, an electrostatic latent image with high resolution and uniform discharge (1°) can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a conventional electron radiation image forming method;
Figure 2 is a schematic sectional view of the chamber used in the present invention;
The figure is an explanatory diagram of a method of forming an X-ray image using the chamber, and FIG. 4 is an explanatory diagram of another method of forming an X-ray image. 7 is an electrode, 8 and 11 are insulating films, 9 is a spacer, 10 is an X-ray absorbing liquid, 12 is an electrode, 13 is a subject, 1
4 is the X-ray source, A is the chamber.

Claims (1)

[Claims] 1. The insulating film 8 of the chamber A is formed by arranging an electrode I having high radiation-inducing properties and an insulating film 8 in parallel using an insulating spacer 9, and filling the gap with an X-ray absorbing liquid 10. The electrodes 12 are stacked outward directly or via an insulating film 11 for receiving a latent image, and both electrodes 7,1
After applying X-rays from the front of the subject 13 placed on the electrode 7 side while applying a voltage between the electrodes 7 and 12,
The insulating film 8 or the insulating film 11 for receiving a latent image is separated from the electrode 12, and an electrostatic latent image is formed by field emission on the insulating film 8 or the insulating film 111. An electron radiation image forming method.