JPH0197981A - Lighting device for static elimination in electrophotographic equipment - Google Patents

Abstract

PURPOSE:To obtain a uniform light quantity distribution in the lengthwise direction of the surface of a photosensitive drum by linearly arranging plural light emitting diodes (LED), which are covered with inverted cone-shaped lenses, as a light source. CONSTITUTION:A LED 12 whose front end is covered with the inverted cone- shaped lens is used, and plural LEDs 12 are linearly arranged on a substrate 13. Since the directional pattern of the light emitted from the LED 12 has a maximum quantity of light in the direction of 45 deg., a light quantity reduction part is not generated when LEDs 12 are linearly arranged at intervals of proper length, and they are arranged in proximity to a photosensitive drum 2. Thus, the surface of the photosensitive drum 2 is illuminated with the uniform light quantity distribution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a lighting device for eliminating static electricity in an electrophotographic apparatus, which is suitable for removing electric charges remaining on a photosensitive drum of an electrophotographic apparatus.

[Prior Art] In an electrophotographic apparatus, reflected light emitted from a light source is guided to a photosensitive drum, toner is attached to an electrostatic latent image formed on the photosensitive drum to form an image, and the image is sent out. The image is transferred to the transferred transfer paper, but after the transfer is completed, it is necessary to remove the residual toner on the surface of the photosensitive drum and further remove the residual charge on the photosensitive drum.

In order to remove the residual charge, an irradiation device for static elimination is provided, and a plurality of neon lamps such as flow lamps are arranged in the illumination device for static elimination as shown in FIG. are doing.

However, there were variations in illuminance distribution among the neon lamps, and it could not be said that they functioned satisfactorily as a lighting device for static elimination. Therefore, as described in Utility Model Application Publication No. 60-107972, a proposal has been made to use lenses to reduce variations in illuminance distribution, but in reality it is expensive and difficult to put into practical use. .

[Problem that the invention seeks to solve]

Conventional lighting equipment for static elimination uses a special neon lamp to match the emission wavelength of the light source with the wavelength of the photoreceptor of the photoreceptor drum, but due to the size of the neon lamp, the distance between the photoreceptor drum and the photoreceptor drum is not too large. Since it cannot be made small, it requires a large amount of light, and compared to the arrangement of neon lamps 9 as shown in FIG. 5, the disadvantage is that the uniformity of the light amount distribution is poor and the amount of heat generated is large, as shown in FIG. 6. It had

The present invention provides a static eliminator for an electrophotographic device in which the emission wavelength of a light source matches the wavelength of a photoconductor of a photoconductor drum, the distance between the light source and the photoconductor drum can be reduced, and uniform light irradiation can be performed. The purpose is to obtain a lighting device.

[Means for solving problems]

For the above purpose, a light emitting diode (
This is achieved by selecting the shape of the lens at the tip of the case of the LED.

[Effect]

A commonly used LED is a type whose tip is covered with a spherical lens, as shown in Figure 7(a).
Dll, and the directivity of its light emission shows the maximum amount of light in the 0° force direction, as shown in (b). Therefore, the above L
When a plurality of EDIIs are arranged in a straight line, the distribution of relative light amount shows a distribution almost similar to the curve shown in FIG. It becomes a device and cannot achieve the above purpose.

However, in the type of LED 12 whose tip is covered with an inverted conical lens as shown in FIG. 7(c), (d)
It has a directional characteristic with a shape that spreads around the periphery as shown in 4.
The maximum amount of light is shown in the 5° direction. The LED 12 is optically referred to as a diverging system, and the light beam incident parallel to the optical axis is refracted and then focused at a focal point on the incident side of the lens. In other words, the optical axis diverges from the focal point after refraction, and the light spreads out, resulting in the same effect as using a concave lens, resulting in the above-mentioned directional characteristics.

The present invention constitutes a lighting device for static elimination using the LEDs 12, and as shown in FIG. 1, a plurality of the LEDs 12 are linearly arranged on the substrate 13 of the lighting device for static elimination,
A fairly uniform light amount distribution is obtained on the opposing photosensitive drum surfaces.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a front view showing an embodiment of a lighting device for static elimination in an electrophotographic apparatus according to the present invention, FIG. 2 is a diagram showing relative light intensity distribution characteristics of the above embodiment, and FIG. 3 is a diagram showing another embodiment of the present invention. FIG. 2 is a partially cutaway perspective view showing an example.

First, the general structure of the electrophotographic apparatus will be explained using FIG. In an electrophotographic apparatus, light 1 emitted from a light source is guided to a photosensitive drum 2 by reflection, and an electrostatic latent image is formed on the photosensitive member of the photosensitive drum 2. Toner is applied to the electrostatic latent image by a developing device 3. It adheres and an image is formed. On the other hand, paper feed section 4
The transfer paper 5 is sequentially sent out from the photosensitive drum 2 and runs close to the photosensitive drum 2, and the transfer paper 5 is transferred to a transfer device 6 provided along the photosensitive drum 2.
As a result, the image on the photosensitive drum 2 is transferred onto the transfer paper 5. Generally after the above transcription has taken place.

In order to remove the charge remaining on the photosensitive drum 2, a static eliminating lighting device 7 is provided. The charge remaining on the photosensitive drum 2 is removed by irradiating it with light having a wavelength matching that of the photosensitive drum 2 .

In this embodiment, the light source of the above-mentioned static elimination lighting device is used as shown in FIG.
) The LED 12 whose tip is covered with an inverted conical lens
As shown in FIG.
A plurality of pieces are arranged in a straight line on 3. Above LED12
The directional characteristics of the light emitted from the LED have the maximum light amount in the 45° direction as shown in FIG. 7(d).
12 arranged in a straight line with proper spacing,
It shows the distribution of relative light intensity as shown in Figure 2, and does not cause a drop in the light intensity unlike when a conventional neon lamp is used as a light source. Since the surface of the photosensitive drum 2 can be irradiated with a substantially uniform light intensity distribution with almost no unevenness, an excellent static elimination effect can be obtained.

In another embodiment of the present invention shown in FIG. 3, a reflective frame 14 having a shape partitioned into a plurality of slots extending in the longitudinal direction is molded from a resin with good reflection characteristics, and the reflective frame 14 is attached to a substrate 13. Alternatively, a static elimination illumination device is formed integrally with the substrate and has the LEDs 12 disposed in individual partitions of the reflective frame 14, and the light emitted from each LED 12 to the surroundings is reflected by the reflective frame partitions. Therefore, a substantially uniform light amount distribution can be obtained as in the above embodiment, and
The relative light amount itself can be further increased.

〔Effect of the invention〕

As described above, the static elimination illumination device for an electrophotographic apparatus according to the present invention includes a plurality of LEDs covered with an inverted conical lens arranged in a straight line as a light source of the static elimination illumination device for removing residual charges on a photosensitive drum. Due to this arrangement, a fairly uniform light amount distribution can be obtained in the longitudinal direction of the surface of the photosensitive drum, and an excellent effect of removing residual charges on the photosensitive drum can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of a lighting device for static elimination in an electrophotographic apparatus according to the present invention, FIG. 2 is a diagram showing relative light intensity distribution characteristics of the above embodiment, and FIG. 3 is a diagram showing another embodiment of the present invention. FIG. 4 is a partially cutaway perspective view showing an example, FIG. 4 is a diagram showing the configuration of an electrophotographic device, FIG. 5 is a partially cutaway perspective view showing a conventional static elimination lighting device, and FIG. 6 is the above static elimination lighting Figure 7 is a diagram showing the relative light intensity distribution characteristics of the device, and Figure 7 is a diagram showing the types of LEDs and their directional characteristics. (a) is a diagram showing a general LED, and (b) is a diagram showing the directional characteristics of the emitted light of the above LED. , (Q) is a diagram showing an LED whose tip is covered with an inverted conical lens used in the present invention, (
d) is a diagram showing the directional characteristics of the light emitted from the LED. 2... Photosensitive drum, 7... Illumination device for static elimination, 12.
... LED having an inverted conical lens, 13 ... substrate,
14... Reflective frame. List 1r21 211. Summer (light drum d-d)

Claims (1)

[Scope of Claims] 1. For static elimination in an electrophotographic device, a plurality of LEDs covered with inverted conical lenses are arranged in a straight line as a light source of a static elimination illumination device for removing residual charges on a photosensitive drum. lighting equipment. 2. The LEDs are each surrounded by a reflective frame made of a resin having good reflective properties and partitioned into a plurality of longitudinally extending slots. Lighting device for static elimination in electrophotographic equipment.