JPS60240003A - Lighting apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Field of the Invention This invention relates to an image forming apparatus using an electrostatic photographic process such as an electrophotographic copying machine, and particularly to an illumination device for eliminating static electricity from a non-image area on the surface of an image carrier. It is related to the device.

(2) Prior art and issues to be solved This type of image forming apparatus, especially a so-called variable magnification type image forming apparatus that can obtain copies of different sizes from an original of the same size, Particularly when obtaining a reduced image, there is a portion on one side of the image carrier that is not exposed to light.

In this way, if there is a non-exposed area that is not exposed to light, the charge will be retained in that area regardless of whether it is related to image formation, so development will be carried out in the subsequent development process, resulting in excessive development. Not only is the toner wasted and wasted, but it can also cause contamination inside the device, so it is recommended to irradiate the non-image area with light to remove the charge in that area. It was normal.

FIG. 2A schematically shows the above-described static eliminating means in a copying machine. It is assumed that an image of a document M to be copied is formed on the surface of a photoreceptor 1 formed in a rotating cylindrical shape through a lens system 2 to form an electrostatic latent image.

In this case, depending on the copying magnification, the width of the effective image area width A of the photosensitive drum 1 is used for image formation in the case shown, and the side edge areas B and C are left unused. shall be.

In such a case, in order to avoid the above-mentioned inconvenience, appropriate light-emitting elements, such as LEDs, are installed in the regions B and C.
3.5, etc., and turn them on to move to the opposing area B.
, C is assumed to be neutralized.

When using an LED as a light emitting element, the LED usually consists of a transparent cylindrical portion 7.8 and a convex lens-shaped condensing section 4, 6 at the tip of the irradiation side. .6 The irradiated light effectively eliminates static electricity, but some of the light beams projected from the cylindrical parts 7 and 8 (particularly the light beam 7' in the case shown) irradiates the image forming area and prevents image formation. This will have a negative impact.

FIG. 2B is a graph schematically showing the light amount distribution on the static eliminating surface of the photoreceptor in the above-mentioned copying machine. In the figure, the solid curve shows the light intensity distribution by the light emitting element 3 in the device shown in Figure 1, the dotted line shows the light intensity distribution by the light emitting element 5, and the chain line shows the combined light intensity field by both light emitting elements.

As can be readily seen from this graph, in the case of a lighting device that uses multiple light emitting elements, a portion of the luminous flux projected from the light emitting elements closest to the image area enters the image area as described above and forms an image. This will have a negative impact on functionality. At the same time, a portion where the amount of light is reduced inevitably occurs between adjacent light emitting elements, which may lead to insufficient charge removal in the portion, resulting in the above-mentioned defects.

In order to avoid such drawbacks, for example, if the gap D3 between the illumination device and the photoreceptor in FIG. However, this may contaminate the light emitter and act as a light shield, resulting in an insufficient amount of light and a resulting charge removal failure.

Further, there is a limit to making the adjacent light emitting elements 3.5 close to each other in view of the structure of the light emitting element 1 in the structure of the relevant part of the copying machine, and it is extremely difficult to correct this.

(3) Purpose of the Invention The present invention has been made in view of the above-mentioned defects in the known devices. This is an illumination device used to eliminate static electricity in a non-image area, and the light emitting element used for this is subjected to total reflection treatment on the part near the image forming side and transmission diffusion treatment on the opposite side. By preventing unnecessary light flux from reaching the image forming area on the surface of the image carrier and by reducing the attenuation in the light intensity attenuation area between adjacent light emitting elements, the non-image area is made as uniform as possible over the entire non-image area. It is an object of the present invention to provide a lighting device that can provide a uniform amount of light and obtain a uniform static elimination effect.

(4) Structure 9 of the Invention Description of Functions and Embodiments In order to achieve the above-mentioned objects, the present invention is directed to a variable magnification type image carrier in which an unused portion inevitably occurs on a part of the surface of an image carrier, as described above. In an illumination device for static elimination that illuminates a non-image area on the surface of an image carrier used in an image forming apparatus, the luminous flux projected from the light emitting element included in the illumination device is directed away from the image area on the surface of the image carrier as much as possible. By applying reflection processing and transmission diffusion processing to the light emitting elements so as to bias the light in the direction in which the light emitting elements Even in the case of using an image sensor, the amount of attenuation in the light amount attenuation portion that occurs between adjacent elements is minimized, and the structure is such that static electricity can be removed uniformly over the entire non-image area.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1A shows one light emitting element forming the lighting device according to the present invention, and exemplifies the case where an LED is used as the light emitting element.

The light emitting element LED3 is a well-known transparent cylindrical part C.
and a lens-shaped convex surface integrally formed with the pulp, and has a light emitting source inside. This light emitting element has basically the same configuration as the lighting device of the copying machine shown in the first figure.

Corresponding parts are denoted by the same reference numerals.

It is assumed that the light emitting element 3 has an image area on the surface of the image carrier on the left side in the figure, and a cylindrical part C on the side corresponding to this.
As can be seen from Fig. 1B, there is a reflectively treated surface 10 extending over 180° in the circumferential direction to enhance the reflective ability by appropriate means such as metal vapor deposition or pasting of metal foil, and a cylindrical surface on the opposite side. The diffused and permeable treated surfaces 11 are formed on each portion by forming minute irregularities with sand gelast or the like in a matte finish, for example.

Since the light emitting element is subjected to such reflection and diffuse transmission processing, the harmful luminous flux 7 in the known device shown in FIG.
The light flux that should be used is reflected by the reflection processing surface 10 and is not projected onto the image area, but is instead projected onto the static elimination areas B and C.

Further, the light beam 7 projected on the opposite side and the light beam traveling in the target direction are projected to the side closer to the charge removal area C of the adjacent light emitting element 5 beyond the charge removal area B handled by the light emitting element 3. become.

Since the projection characteristics of the projected light beam are as described above, the light beam from the illumination device that illuminates the non-image area does not enter the edges of the image area on the surface of the image carrier, so that the image in that area is not visible. There is nothing that will cause it to deteriorate.

Furthermore, even when a plurality of light emitting elements are arranged in a row and one or several of them are used depending on the magnification, the above-mentioned effect is maintained, and the above-mentioned effect is maintained in the overlapping area of the irradiation areas of adjacent light emitting elements. Since the light flux on the diffusion side is projected, the amount of light applied to the relevant portion increases, and a uniform amount of static elimination light can be obtained over the entire length of the predetermined static elimination area.

FIG. 1C shows the light intensity distribution seen in the longitudinal direction of the charge removal areas B and C when two light emitting elements according to the present invention are used, where the solid line shows the light emitting element 31, the dotted line shows the light intensity distribution by the light emitting element 5, and As can be seen from this graph, unnecessary light flux on the image area side is cut, and the drop in the amount of light in the overlapped irradiation portion by adjacent light emitting elements is small, and the amount of light is leveled.

Further, the lengths of the reflective surface 10 and the diffuse transmitting surface 11 of the light emitting element viewed in the circumferential direction are not limited to those described above, but can be changed as appropriate depending on the configuration of the image forming apparatus.

(5) Effects of the Invention Since the present invention has the configuration described above, it is possible to remove static electricity from a non-image area that occurs in a part of the image carrier when changing the magnification of a variable magnification type image forming apparatus, especially when reducing the magnification. When this is done, the boundary between the image area and the non-image area is clearly demarcated to prevent deterioration of image quality, and the non-image area can be neutralized as uniformly as possible, thereby preventing staining of the relevant part of the transfer material. There is no.

[Brief explanation of drawings]

1A is a side view showing a light beam projection mode of a light emitting element of a lighting device according to the present invention, FIG. 1B is a sectional view taken along line A-A in FIG. 1A, and FIG. 1C is a lighting device according to the present invention. FIG. 2A is an explanatory diagram showing the structure of a conventional variable-magnification copying machine for removing static electricity from a non-image area. FIG. 2B is a graph showing the light amount distribution characteristics of the irradiation device shown in FIG. It is a graph.

Claims (1)

[Claims] What is claimed is: 1. An illumination device comprising a light emitting element having a light emitting source inside a transparent cylinder, and a reflection treated surface and a diffuse reflection treatment surface formed on the periphery of the transparent cylinder to deflect a projected light beam.