JPS59828B2 - cathode ray tube printing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cathode ray tube printing device, and more specifically, to an electrophotographic printing device using a cathode ray tube as a light source.

In this type of conventional cathode ray tube printing apparatus, as shown in FIG. After cleaning, the photosensitive drum is uniformly charged to a polarity of 1 using a charger 3, and then the uniformly charged surface of the photosensitive drum is exposed to optical image information from a cathode ray tube 4. An electrostatic latent image of desired image information is formed on the surface of the photosensitive drum 1, this electrostatic latent image is made visible by the developing device 5, and this visible image is transferred to the recording paper T by the transfer device 6. After the image is transferred to the computer, it is configured to be fixed by a fixing device (not shown).

However, in printing equipment that uses this cathode ray tube, a high voltage of several hundred volts is applied to the back side of the cathode ray tube, so a voltage of several hundred volts is induced on the surface of the cathode ray tube as well. . When the electric field strength between the cathode ray tube and the photosensitive drum due to this induced voltage increases, discharge occurs between the surface of the cathode ray tube and the photosensitive drum, causing disturbances in the electrostatic latent image, causing background smudges and missing characters. This has the problem of causing a problem in that obtaining good image quality is hindered. For example, the potential of the surface of the photosensitive drum is -600 [V] at the part exposed to light.
, the voltage is about +300 [V] in the part not exposed to light, and on the other hand, a voltage of about +400 [V] is induced on the surface of the cathode ray tube. In this case, if the gap length between the surface of the cathode ray tube and the photosensitive drum is 100 [μm], this 100 [μm]
By applying a voltage of 1000IIV], which is higher than the discharge starting voltage, to the gap of [μm], a discharge occurs between the cathode ray tube and the photosensitive drum, the negative charge on the photosensitive drum disappears, and as a result, the discharge occurs. Toner does not adhere to the areas where the marks occur, resulting in cut-out characters. Conventionally, an optical fiber tube is provided with one end surface in contact with the tube surface of the cathode ray tube, and the other surface of the optical fiber tube is provided with an optically transparent material for removing the electric field applied to the outside of the optical fiber tube. An electrophotographic apparatus is known that has a configuration in which a conductive layer is provided, the conductive layer is grounded through a high resistance, and the conductive layer is further covered with an optical fiber plate. However, this method has a problem in that electric charges are accumulated in the dielectric optical fiber plate, and discharge failure between the cathode ray tube and the photosensitive drum cannot be reliably prevented. In view of the problems in the prior art described above, the main object of the present invention is to reduce the distance between the surface of the cathode ray tube and the photosensitive drum, and to increase the reliability of preventing discharge failure between the cathode ray tube and the photosensitive drum. It's about doing.

In the present invention, there is provided a photosensitive drum having a conductive substrate, a photoconductive layer provided on the conductive substrate, and a transparent insulating layer adhered to the surface of the photoconductive layer; and a cathode ray tube having an electron tube body portion, an optical fiber bundle portion provided on the surface of the electron tube body portion, and a transparent conductive film layer provided on the surface of the optical fiber bundle portion, and the transparent conductive layer of the cathode ray tube. A cathode ray tube printing device is proposed which includes a grounding device for grounding a membrane layer.

Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments. FIG. 2 shows a cathode ray tube printing apparatus as an embodiment of the present invention.

The cathode ray tube printing device 11 includes a photosensitive drum 12 that is rotated at a constant speed in the direction of arrow B by a rotational drive device (not shown);
Cathode ray tube 1 provided close to the circumferential surface of photosensitive drum 12
3. The photosensitive drum 12 includes a conductive substrate 14 made of a conductive material such as aluminum, and a conductive substrate 14 made of a conductive material such as aluminum.
a photoconductive layer 15 of a material such as selenium disposed thereon;
and a transparent insulating layer 16 adhered to the surface of the photoconductive layer 15, and the surface of the photosensitive drum 12 is cleaned by the cleaning device 1.
After being cleaned by 7, it is primarily charged to a negative polarity by a primary charger 18, and then secondarily charged to a positive polarity by a secondary charger 19. The cathode ray tube 13 has a cathode ray tube portion 13a that displays a required image and/or text information on a fluorescent surface based on an information signal from an information signal generation circuit (not shown).
and an optical fiber bundle part 13b provided on the surface of the cathode ray tube part 13a in order to project the displayed information onto the surface of the photosensitive drum 12.
A NESA film 20, which is a transparent conductive film layer, is provided on the surface of the photosensitive drum 3b, that is, the surface facing the photosensitive drum 12.

The NESA membrane 20 is grounded to remove the positive voltage generated on the surface of the optical fiber bundle portion 13b for the above-mentioned reasons.
This surface is held at ground potential. Note that since the Nesa film is transparent, no hindrance occurs to the exposure operation performed on the surface of the photosensitive drum 12 by the cathode ray tube 13.
In Figure 2, 5 is a developing device, 6 is a transfer device, 7 is a recording paper,
21 is a fixing device. In this way, when the Nesa membrane 20 is provided on the surface of the cathode ray tube and the Nesa membrane 20 is grounded, for example,
The portion of the surface of the photosensitive drum 12 that is exposed to light is ~60
Even if the voltage is about 0 [V], the potential on the surface of the cathode ray tube is 0 CV], so the voltage difference between the two is 600 CV.
] Therefore, if the margin corresponding to the decrease in the potential on the surface of the cathode ray tube is used to shorten the distance 1 between the surface of the cathode ray tube and the surface of the photosensitive drum, exposure with better resolution can be achieved. can be done. That is, since the relationship between the gap length 1 and the discharge starting voltage E is as shown in FIG. 3, the voltage applied to the gap is about 1000 [V. ll (assuming the positive potential on the surface of the cathode ray tube is +400CV), and therefore, the third
From the figure, the value of l must be approximately 125 [μm] or more.

However, if a Nesa membrane is provided and grounded, the voltage across the gap will be 600CV], so 1 is approximately 50[μm].
It can be done. In addition, in general, the resolution at the time of exposure,
In order to improve the light transmittance, some kind of optical device, such as a neptical, is installed in front of the cathode ray tube. Faiba. It is common practice to provide a plate or self-adhesive device, but when such an optical device is provided, the distance between the optical device and the photosensitive drum must be further shortened in order to obtain good exposure characteristics. There is a need. Therefore, when such an optical device is provided, a Nesa film is provided on the front surface of the optical device, that is, on the surface facing the photosensitive drum, and this is grounded, thereby reducing the amount of energy generated due to the shortening of the gap length. The discharge phenomenon that occurs can be more reliably prevented. Furthermore, in the above embodiment, the case where the voltage across the gap is reduced by grounding the NESA film is described, but it is also possible to apply a negative bias voltage to the NESA film to reduce the voltage applied to the gap to approximately 0 CV]. By applying a negative bias voltage in this way, the occurrence of discharge can be more reliably prevented.

According to the present invention, it is possible to reduce the distance between the surface of the cathode ray tube and the photosensitive drum, and to increase the reliability of preventing discharge failure between the cathode ray tube and the photosensitive drum.

This helps in printing with higher resolution and better image quality.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a conventional cathode ray tube printing device, FIG. 2 is a diagram showing a cathode ray tube printing device as an embodiment of the present invention, and FIG. 3 is a diagram showing gap 1 and firing voltage E. It is a characteristic diagram showing the relationship between. 11... Cathode ray tube printing device, 12...
Photosensitive drum, 13...Cathode ray tube, 13a...
... Braun tube part, 13b... Optical fiber bundle part, 14... Conductive substrate, 15...
Photoconductive layer, 16...Transparent insulating layer, 17...
...Cleaning device, 18...Primary charger,
19... Secondary charger, 20... Nesa membrane.

Claims (1)

[Scope of Claims] 1. A photosensitive drum having a conductive substrate, a photoconductive layer provided on the conductive substrate, and a transparent insulating layer adhered to the surface of the photoconductive layer; facing each other,
A cathode ray tube having an electron tube body portion, an optical fiber bundle portion provided on the surface of the electron tube body portion, and a transparent conductive film layer provided on the surface of the optical fiber bundle portion, and the transparent conductive film layer of the cathode ray tube. A cathode ray tube printing device comprising a grounding device for grounding. 2. The cathode ray tube printing apparatus according to claim 1, wherein a bias voltage is applied to the transparent conductive film layer.