JPS5930914Y2 - Corona charger in simultaneous charging exposure electrophotography - Google Patents

Description

[Detailed description of the invention] The present invention relates to a corona charger for simultaneous charging and exposure for forming an electrostatic latent image of a belt-shaped scanning light image such as cathode ray tube laser light on a photosensitive element in simultaneous charging and exposure electrophotography. It is something.

A photosensitive element is formed by laminating and bonding a photosensitive layer composed of a photoconductive substance in a state in which the photosensitive layer is sandwiched between a light-transmitting highly insulating thin layer (hereinafter referred to as an insulating layer) and an electrode layer on both sides of the photosensitive layer. use,
In the first step, the surface of the photosensitive element is charged with a specific polarity, and then in the second step, static electricity is applied to the surface of the photosensitive element using an arbitrary means under such polarity that the surface is charged with a polarity opposite to that in the first step. Simultaneous charge exposure electrophotography in which a band-shaped test light image of brown reed or the like is projected through a lens or the like while applying a charge, and then the entire surface is exposed to form an electrostatic latent image on the surface of the photosensitive element. When carrying out the process, it is convenient to use a corona discharge as a means of imparting an electrostatic charge in the second step.

However, special consideration is required in order to use a corona charger for simultaneous charging and exposure of a strip-shaped scanning light image of a cathode ray tube or the like.

It is very difficult for the corona charger for simultaneous charging and exposure, which has been used in the prior art, to perform optical image exposure using a strip-shaped scanning light image of a cathode ray tube or the like, and at the same time uniformly apply charging to the photosensitive terminal surface.

For strip-shaped scanning light images from cathode ray tubes, etc., conventional corona dischargers for strip exposure can form electrostatic latent images to some extent in some areas, but for the following reasons, uniform unevenness over the entire surface cannot be formed. No electrostatic latent 8 image could be formed.

The light images normally used in electrophotography are
Irradiation is performed using a halogen lamp, iodine lamp, etc., and the reflected light image is projected onto the surface of the photosensitive element using a lens or the like.

At that time? Light image cicada 1. In order to fix the illumination strike and move the photographic subject so that it becomes zero relative to the moving speed of the photosensitive element, the light image is always transferred to the photosensitive plate using a corona charger on the photosensitive element. can be projected uniformly.

However, when attempting to form an electrostatic latent image of a band-shaped scanning light image on a cathode ray tube, etc., the light image is drawn by scanning as a bright spot on the face plate of the cathode ray tube, etc., so the moving speed of the photosensitive element and the light The relative relationship between image scanning speed and scanning distance becomes a problem, and the discharge wire of the corona charger,
Since the problem arises that the grid casts a shadow on the optical image, a regular corona charger cannot form a uniform electrostatic latent image.

An object of the present invention is to provide a corona charger for simultaneous charging and exposure, which solves the disadvantages of the conventional devices described above.

In simultaneous charging exposure electrophotography, a strip-shaped scanning light image is scanned as a bright spot on the face plate of a cathode ray tube, etc., and a light image is exposed at the same time as secondary charging to obtain an electrostatic latent image. According to the present invention, in order to form electrostatic penetration in a direction perpendicular to the direction of movement, that is, horizontally, the corona charger, the grid, and the discharge wire are connected to the movement of the photosensitive element. It is arranged not along a direction perpendicular to the direction, but along a direction shifted by an appropriate angle from the right angle.

Furthermore, according to the present invention, the discharge wire of the corona charger is
The grid, which is arranged so as not to be in the shadow of the light image projected onto the surface of the photosensitive element, and which is used to uniformly discharge the corona charger, is also arranged so as not to be in the shadow of the light image projected onto the surface of the photosensitive element. be done.

Next, embodiments of the present invention will be described in detail based on the accompanying drawings.

Photosensitive element 11 used in electrophotography to which the present invention is applied
/'i, As shown in FIG. 1, it is formed by laminating and bonding a photosensitive layer 1A, a highly insulating thin layer IB, and an electrode layer IC.

To explain the photosensitive layer 1A, it has a photoconductive material as a component, such as a thin layer made by binding CdS crystal powder with a binder, and traps charges in a trap level in an electric field and is thermally excited. Alternatively, it has the property of forming so-called sustained internal polarization that is released by irradiation with light.

Such a photosensitive element 1 is mounted on a drum 2 as shown in FIG.

First, in the first step, a DC voltage of (→) is applied to the corona discharger 3 on the surface of the highly insulating thin layer 1B to perform charging (in the experiment, approximately +1400 to +2000 V).
f) was the surface potential).

Next, as a second step, the light image emitted from the face plate 4A of the cathode ray tube 4 is passed through the lens 5,
While reflecting the optical image and projecting it onto the highly insulating thin layer 1B, ←) the corona charger 7 performs second charging.

At that time, the entire surface is exposed using the entire surface exposure device 8.

At that time, for example, on the surface of the highly insulating thin layer 1B, the surface potential is +50 to +200 V in the dark area, and the surface potential is -500 to -700 V in the bright area (i.e., the location irradiated as a light image from the cathode ray tube 4). An electrostatic latent image is formed.

This formed electrostatic latent image is developed into a visible image by a developing device 9 using a developer in which colored toner charged in (G) and carrier (iron powder) are stirred, and transferred to a transfer paper 10 by a corona discharger 11. ←) Transfer is performed by applying high DC voltage, and the fixing section 1
In step 2, the visible image toner transferred to the transfer paper 10 is fixed to obtain a copy image.

Since some toner remains on the surface of the high insulating layer of the casing even after transfer, cleaning is performed in the cleaning section 13.
The photosensitive element can be used repeatedly and continuously.

The following improvements have been made in accordance with the present invention in order to obtain a good copy image in the simultaneous charging exposure electrophotography method for obtaining a copy image of the strip-shaped scanning light image of a cathode ray tube.

Normally, the light image displayed on the face plate 4A of a cathode ray tube is a group of electrons generated by heating the cathode, which are accelerated by the anode voltage and collide with the phosphor to emit light. The light emitted from the phosphor becomes an extremely small bright spot.

This electron beam, in combination with a signal applied to a control grid or cathode and deflected by vertical and horizontal deflection coils, expresses an arbitrary optical image on the phosphor surface.

Although the optical image is a line-like or band-like scanning optical image in the horizontal direction, the rotational circumferential speed of the photosensitive element drum 20 needs to be determined according to the relative relationship between the scanning speed and the scanning distance.

The scanning of the light image is not carried out in a direction perpendicular to the rotational direction of the photosensitive element drum 2, but in a direction shifted by an appropriate angle from the right angle, so that the light image is projected across the photosensitive element 1 at right angles. must be carried out.

This shift angle is determined by taking into consideration the scanning speed of the optical image, the scanning distance, and the rotational speed of the photosensitive element drum.

Therefore, a corona charger is required that can simultaneously charge and expose optical images at appropriate angles.

Details of the corona charger 7 as an embodiment of the present invention are shown in FIGS. 3, 4, and 5.

FIG. 3 is a top view showing details of the corona charger 7 of FIG. 2.

A drum 2 having a photosensitive element 1 rotates in the six directions of arrows, and the optical image on the face plate 4A of the cathode ray tube 4 is
Scanning is performed in the direction indicated by arrow B, which is deviated by θ degrees from the direction perpendicular to the direction of rotation of drum 2, and within the dotted line in the figure.

The discharge wire 7A, the corona house 7B, and the grid 7c are provided along a direction forming an angle θ.

ID, the grid and discharge wire attachments are insulators.

The positional relationship among the discharge wire 7A, the corona house 7B, and the grid IC is shown in schematic cross-sectional views in FIGS. 4 and 5.

To explain FIG. 4, a corona plate is provided with plates facing each other on both sides of the photosensitive element 1.
7B, a discharge wire 7A is stretched at or near the center of A in the projected light image.

In order to generate a uniform discharge 1, the Tsukuri lid IC is provided outside the center of the optical image.

When disposing the discharge wire 7A in the optical image plate, the diameter of the discharge wire 7A must be 80μ or less even when the distance B from the photosensitive element 1 is 8 mm or more.
In case of C, it was found that since the distance C between the grid and the photosensitive element 1 could not be maintained, it was found that unless the diameter of these grids was 30 μm or less, they had to be provided outside of A in the optical image.

That is, if the grid 7c is provided in the light image A, the light image irradiation on the photosensitive element 1 will be in the shadow of the grid 7C, and there is a problem that the information in the scanned light image cannot be expressed in a line shape in that part in the copied image. I found out that it happens.

Therefore, when the diameter of the discharge wire 7A exceeds 80μ or when the diameter of the grid 7C exceeds 30μ or more, it is necessary to provide them outside A in the scanning light image.

FIG. 5 shows an example where the diameter of the discharge wire 7A exceeds 80 μm and the diameter of the grid 7C exceeds 30 μm, and they are provided outside A in the scanning light image.

As shown in FIG. 5, the number of discharge wires and grids can be plural or more than three.

According to the corona charger of the present invention, uniform and even charging can be applied during scanning of the optical image, and a uniform electrostatic latent image can be formed. When developed and transferred to the transfer paper 10 using the transfer corona discharger 11, a uniform and even copy image can be formed.

[Brief explanation of drawings]

Figure 1 of the accompanying drawings is a schematic cross-sectional view showing a photosensitive element used in the simultaneous charging exposure electrophotography method to which the present invention is applied, and Figure 2 is a simultaneous charging exposure electrophotography to which the present invention Q is applied. 3 is a top view of a corona charger as an embodiment of the present invention, and FIGS. 4 and 5 are a corona house, discharge wire, and grid of the corona charger of the present invention. It is a schematic sectional view showing the positional relationship of. 1...Photosensitive element, 7...Corona charger, 7A...Discharge wire, 7B...Corona house, IC...Grid.

Claims (1)

[Scope of utility model registration claim] Moving at a predetermined speed. The light image is scanned in a direction shifted by an appropriate angle from the right angle with respect to the moving direction of the photosensitive element, so that the scanning light image is projected across the surface of the photosensitive element at right angles, and at the same time, 1. A corona charger for use in simultaneous charge exposure electrophotography for charging a surface, characterized in that a corona house, a discharge ear, and a grid are arranged facing each other along the scanning direction of the optical image.