JPS59160368A - Electrostatic image reading method - Google Patents

Abstract

PURPOSE:To obtain stably an electrostatic latent image with the close amount of information by providing a surface insulating layer, semiconductor layer which conducts by being excited by an electromagnetic wave, and conductor layer. CONSTITUTION:The polarity of uniform electrostatic charge in a primary process (a) is made negative when a photoconductor 2 is a P type semiconductor or negative when it is an N type semiconductor, and corona charge is performed. Then, corona charge with the polarity opposite to that of the primary charge is performed by a corona charger 5 in the 2nd process (b) and irradiation with an original image L1 is carried out at the same time; the photoconductive layer 2 conducts at light parts to charge the surface of the insulating layer 1 positively, and negative charges remain at dark parts. When an electrostatic holder 10 is irradiated with light L2 uniformly in the 3rd process (c), the photoconductive layer 2 conducts, so an electrostatic latent image corresponding to the original picture is formed on the insulating layer 1. The surface of the electrostatic latent image holder is discharged successively in the 4th process (d) by a roller 6 having the surface grounded to transfer the electrostatic image to between semiconductor layers. The transferred electrostatic image is scanned in the 5th process (e) by an electromagnetic wave L3 to discharge static charges, whose discharging current is read out as a signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention electrostatically records image information on an electrostatic image carrier;
The present invention relates to a method of reading out the recorded electrostatic image as an electrical signal.

The wandering method of recording an image as an electrostatic image on an electrostatic image holder and reading out the electrostatic image as a time-series Denki No. 48 is disclosed, for example, in Japanese Patent Application Laid-Open No. 54-31219 and Japanese Patent Application Publication No. 1983 [1983]. (-50(1
It is described in Publication No. 704, etc.

As disclosed in the above-mentioned publication, the conventionally known electrostatic image reading blur method is based on an electrostatic image holder having an insulating layer and a photoconductive layer sandwiched between an insulating layer and a photoconductive layer. A recorded electrostatic image is transferred to a photoconductive layer by short-circuiting two conductive layers externally, and the transferred electrostatic image is discharged by scanning with light.
The discharge current is read out as a signal. In this way, the conductive layer covers the entire surface of the insulating layer and the photoconductive layer, and when the conductive layer is short-circuited externally, dislocation of the electrostatic image occurs instantaneously over the entire surface, and then it takes time for the electrostatic image to be dislocated. There is a delay. Particularly when the area of the electrostatic image holder is large, the delay becomes more severe as the scanning end approaches, and during this time the electrostatic charge decays, making it impossible to obtain a sufficient S/N ratio. on the other hand,
There are limits to increasing the scanning speed due to limitations such as the travel time of carriers in the photoconductive layer and the dark discharge time constant determined by the dark specific resistivity and dielectric constant of the photoconductive layer. Therefore, there is a limit to increasing the light spot scanning richness in an attempt to improve resolution.

For example, when Se is used for the photoconductive layer, the dark specific resistivity of Se is approximately 1012 Ω・m, the relative dielectric constant is approximately 6.3, and the dielectric constant of vacuum is 8.855 Assuming the time constant tc, tc - dielectric constant of vacuum x specific dielectric constant x specific resistivity = 8.855X t O-12X 6 .

3×10′ 2 =60 C seconds). Now, let us assume that the area of the electrostatic image holder is 300 + nm x 300 mm.
When scanning the light spot at t/mm, the entire surface is (300 x 10)
2-9XIO It is necessary to irradiate light spots at 6 locations.

On the other hand, since it takes about 5 x IO-6 seconds for the discharge current to finish flowing after the light spot is irradiated, it takes t = 9 x 10 to complete the light spot scanning of the entire area of the electrostatic image holder. '
A time of X 5 X 10-'''-45 (seconds) is required.

When this time t and the dark time constant tc are compared, they are approximately the same. Therefore, it is necessary to compensate for the amount of charge lost due to dark discharge for electrical signals detected from locations where light spot scanning will be performed later. Moreover, when the same area is scanned several times and converted into an analog quantity according to the latent image intensity of the edge area, there is no time leeway. Overall,
There is a disadvantage that the electrostatic latent image must be scanned for a light spot immediately after the electrostatic latent image is transposed to complete the conversion into an electrical signal.

The present invention aims to eliminate the above-mentioned disadvantages.

In order to achieve this object, the present invention has a surface insulating layer 1, a semiconductor layer 2 which is excited by electromagnetic waves and becomes conductive, and a conductive layer 3. Primary step (a) of uniformly charging the electrostatic image carrier 1
A secondary step (b) of forming an electrostatic image by irradiating electromagnetic waves L1 for image formation and charging the electrostatic image carrier with a polarity opposite to that of the previous step or with alternating current; electromagnetic wave L
The tertiary step (
C), a quaternary step (cl) in which the surface of the electrostatic image holder is sequentially destaticized and the electrostatic image is transferred between the semiconductor layers, and the transferred electrostatic image is scanned with an electromagnetic wave L3 to eliminate the electrostatic charge. This electrostatic image reading method includes a tertiary step (e) of discharging charges and reading out the discharge current as a signal.

The present invention will be explained in detail below based on the drawings.

FIG. 1 shows a case where an image is illuminated from the insulating layer l side on an electrostatic image holder 10 whose basic structure is an insulating layer 1, a photoconductive layer 2, and a conductive substrate 3.

First, the polarity of uniform charging in the primary step (a) is selected to be negative when the photoconductive layer 2 is a P-type semiconductor, and positive when it is an N-type semiconductor, and corona charging is performed. In the example, an n-type semiconductor is used,
It is negatively charged by the corona charger 4. At this time, if the polarization within the photoconductive layer 2 is insufficient due to insufficient charge injection from the conductive substrate 3, light irradiation is performed substantially simultaneously with charging.

Next, as a second step (b), corona charging with a polarity opposite to the -order charging, that is, positive or alternating current AC charging is applied by the corona charger 5, and at the same time, the original image L1 is irradiated. The right half is the bright area and the left half is the dark area. In bright areas, the photoconductive layer 2 is electrically conductive, so positive charges are generated on the surface of the insulating layer l; however, in dark areas, the photoconductive layer 2 is not electrically conductive, and is therefore attracted to the positive charges of the photoconductive layer 2. Negative charges on the surface of the insulating layer 1 remain.

In the next third step (C), light L is uniformly applied to the electrostatic image carrier 10.
When irradiated with 2, the photoconductive layer 2 becomes conductive, so that an electrostatic latent image corresponding to the original image is formed on the insulating layer 1.

When reading out this electrostatic latent image, in the fourth step (d), when the grounded conductive rubber roller 6 is pressed against the surface of the insulating layer 1 and rotated, the charge on the surface of the insulating layer 1 is removed. A new electric field is induced and the charges of the electrostatic image are transferred to the photoconductive layer 2. As shown in the fifth step (e), when the portion from which the static electricity has been removed is immediately scanned by the light L3, a discharge occurs depending on the brightness and darkness of the original image, and an electric signal is output from the conductive layer 3. The greater the density of the dark part of the original image, the greater the electrical signal t.

This signal is input to an operational amplifier (not shown) etc. to increase the IJ.
and becomes an image signal source.

As explained above, according to the electrostatic image reading method of the present invention, since the insulating layer 1 is not in contact with the conductive substance, the total exposure in step (C) is not performed as in the conventional method. There is no need to scan the light spot. Steps (d) and (e)
Since the electrostatic image charge is sequentially read out from the point where it is transferred to the photoconductive layer 2, there is no need to correct dark decay even in the case of a large-area image.

In addition, it is possible to make the light spot scanning sound intensity as fine as necessary, and it is possible to generate electrical signals with a high amount of information (1), making it possible to read out images with high resolution. Zarani Shizuka'711! :
Since the latent image is formed on an insulating layer and is not in contact with a conductive material, the electrostatic latent image charge is stable over a long period of time, making this method advantageous when used as an image memory.

After the electrostatic latent image is formed, when reading out the signal, the static electricity is removed using the conductive roller 6 in the above example, but other static electricity removal means such as a corona discharger, wiping with a solvent-impregnated cloth, needle electrodes, etc. You can go there.

The lights L1, L2, and L3 in the above example are not limited to visible light. Any electromagnetic wave with a wavelength that excites the photoconductive layer 2 and makes it conductive when irradiated onto the photoconductive layer 2 may be used.

FIG. 2 shows an embodiment in which such light is converted into X-rays.

In the second step (b) of the above example, the electromagnetic wave irradiation light for image formation is
In the case of a line, it is necessary to place the subject as close as possible to the image holder to prevent blurring of the image. Therefore, when a subject is placed on the side of the corona charger 5, the height of the charger, the gap between the subject stand and the charger, and the gap between the charger and the electrostatic image holder will affect the distance of the subject. The resolution deteriorates as the image moves away from the electrostatic image holder. Therefore, if the subject ○ is placed on the substrate 9 side of the electrostatic image holder 11 as shown in FIG. 2, an X-ray transmission image with high resolution can be obtained.

Further, as for the structure of the electrostatic image holder 11, since the X-rays are irradiated from the substrate 9 side, it is necessary to select a substrate 9 having high X-ray transmittance. If the substrate 9 is insulating, it is necessary to laminate the conductive layer 8. Furthermore, the photoconductive layer 2
It is necessary to insert a barrier layer 7 between the conductive layer 8 and the conductive layer 8 in order to prevent charges from flowing into the conductive layer 8.

The latent image forming method is the primary step (a) when the image is irradiated from the substrate 9 side, and if the photoconductive layer 2 is p-type, the polarity of the primary charge is selected to be positive, and the light is uniformly applied from the insulating layer 1 side. Corona charging occurs during irradiation. Next, in the second step (b>), corona charging or AC charging is performed with a polarity opposite to the -order charging, and at the same time, X-rays Lx are irradiated through the object O to the electrostatic image holder.
(Step (C) of adjusting, step (d) of reading out the electrostatic latent image)
, (e) are the same as in the embodiment shown in FIG.

In each of the above embodiments, a case has been described in which the semiconductor layer of the image carrier is a p-type semiconductor, but if it is an n-type semiconductor, it is preferable that the polarity of the charged charges be reversed.

[Brief explanation of the drawing]

FIG. 1 is a process explanatory diagram of an embodiment of an electrostatic image reading method to which the present invention is applied, and FIG. 2 is a process explanatory diagram of another embodiment. 2 is an insulating layer, 2 is a semiconductor layer, 3 is a conductive layer, and 10 is an electrostatic image holder. Agent Ikki 1
) Recommendation, --yu: (Ct)
, (b) Figure 2 (o) (b) (c) Figure 1 (c) (d) (e) (d) (e)

Claims (1)

[Claims] (1) A primary step of uniformly charging the surface of an electrostatic image holder having at least a surface insulating layer, a semiconductor layer excited by electromagnetic waves to become conductive, and a conductive layer; and the electrostatic image. While irradiating the holding body with electromagnetic waves for image formation,
Is the charging polarity of the previous and next steps opposite or alternating current? a secondary step of forming an electrostatic image by applying f'I electrons; a tertiary step of uniformly irradiating the electrostatic image carrier with '·E magnetic waves; A quaternary process in which static electricity is removed in sequence and the electrostatic image is transferred between the conductor layers, and the transferred electrostatic image is scanned with electromagnetic waves to discharge the charge onto the static image, and the discharge current is read out as a signal. An electrostatic image reading method consisting of a fifth step.