JPS61162065A - Illuminating device - Google Patents

Abstract

PURPOSE:To prevent picture quality from deterioration or notching and to prevent the titled device from useless consumption by forming images having rectangular transmission/diffusion processing surfaces on an image carrier through a lens system. CONSTITUTION:Light flux radiated from light emitting chips 11, 12 of light emitting elements 5, 6 is irradiated to the transmission/diffusion processing surfaces 13, 14 directly or after being reflected by reflection processing surfaces 15, 16. The surfaces 13, 14 diffuse the light flux so as to light up with high brightness and also transmit the light flux so as to be used as rectangular secondary light sources. The images of the surfaces 13, 14 are formed on the image carrier 3 through lens systems 7, 8. Thus, the images of the surfaces 13, 14 are formed on the image carrier 3 and light radiated from other part hardly reaches the image carrier 3. Therefore, the light distribution on the surface of the image carrier 3 makes it possible to illuminate only non-picture areas B, C uniformly without the leakage of light to a picture area D and the areas B, C can be uniformly destaticized by controlling the positions of respective light emitting elements 5, 6 and the lens systems 7, 8 so that the areas illuminated by the light emitting elements 5, 6 are formed adjacently without any gaps.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an image forming apparatus that uses an electrostatic photographic process, such as an electrophotographic copying machine, in which static electricity is removed from non-image areas on the surface of an image carrier. The present invention relates to lighting devices for

(Prior Art) As an example of this type of image forming apparatus, there is one shown in FIG. 5, for example. This is because an image of the document M to be copied is formed on the surface of a rotating cylindrical image carrier 21 that has been charged in advance through a lens system 22, and an electrostatic latent image is formed on the surface of the image carrier 21. It is something. Further, by adjusting the position of the lens system 22, etc., copies of different sizes can be obtained from the same size original M to be copied. by the way,
In such a so-called variable magnification type image forming apparatus,
When changing the magnification, especially when obtaining a reduced image, convergence is used for the image area with respect to the effective image area width A of the image carrier 21,
The side edge areas B and C are non-image areas, that is, areas that are not exposed.

In this way, if there is a non-exposed area on the image bearing member, charge is retained in that area even though it is not related to image formation, so development will be performed in the subsequent development process, and excessive toner will be removed. Not only is it wasted and wasteful, but
Since this may place a burden on the cleaner or contaminate the inside of the device, it is common practice to irradiate the non-image area with light to eliminate the charge in the area.

Conventionally, an illumination device for irradiating light to the non-image area has been provided with appropriate light emitting elements, such as LEDs 23° and 23', arranged in the non-image areas B and C, as shown in FIG. , are turned on to eliminate static in the non-image areas B and C. When using LED as a light emitting element,
The LED generally consists of a transparent cylindrical portion 24 , 24 ′ and a convex lens-shaped condensing portion 25 , 25 ′ at the tip on the irradiation side.

(Problems to be Solved by the Invention) However, in the above lighting device, the light condensing section 25 of the LED
, 25' effectively eliminates static electricity, but some of the light beams projected from the cylindrical parts 24, 24' (particularly the light beam 26 in the illustrated case) irradiates the image area and prevents image formation. This will have a negative impact on the

FIG. 6 is a graph schematically showing the light amount distribution on the charge removal surface of the image carrier surface in the image forming apparatus as described above. In the figure, the solid curve shows the light intensity distribution by the light emitting element 23 in the device shown in FIG. 5, the dotted line shows the light intensity distribution by the same light emitting element 23', and the chain line shows the total light intensity distribution 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, causing the image to become visible. This will have a negative effect on the formation function. Along with this.

A portion where the amount of light is reduced inevitably occurs between adjacent light emitting elements, and this may result in insufficient charge removal in that portion, resulting in the defect that the toner is consumed and wasted as described above.

In order to reduce the influence of such harmful light, it is possible to reduce the distance between the LED and the image carrier, but in this case, the rotation of the image carrier and the accompanying micro vibrations may cause the air to As a result, floating toner, dust, etc. are induced between the LED and the surface of the image carrier.
There was a risk that the particles would adhere to the ED, making it impossible to obtain an effective amount of light and reducing the static elimination effect.

The present invention has been made to solve the problems of the prior art, and its purpose is to provide a novel illumination device that erases unnecessary charges on an image carrier. In particular, it eliminates the drawback that light from a light-emitting element that irradiates a non-image area enters the image area and causes unnecessary static neutralization, resulting in deterioration and loss of image quality, and also prevents wasteful consumption of toner. An object of the present invention is to provide an illumination device capable of accurately demarcating the edge of an image area without bringing a light emitting element close to an image carrier.

(Means for Solving the Problems) Therefore, in order to achieve the above object, the present invention is arranged so as to face the surface of an image carrier, and by illuminating the image carrier, the image carrier is In a lighting device for eliminating unnecessary charges on a body, a rectangular transmission-diffusion treated surface for transmitting and diffusing light is formed at the irradiation side tip of a light-emitting element equipped with a light-emitting source, and the light-emitting element is A reflection treated surface that reflects light from the light emitting section onto the transmission diffusion treated surface is formed at least around the irradiation side tip part, and a lens system is disposed between the light emitting element and the image carrier. It is configured.

(Example) The present invention will be explained below based on the illustrated example. Third
The figure shows an image forming apparatus 2 using an illumination device l according to the present invention.
This image forming apparatus 2 is formed into a rotating cylindrical shape and applies an original to be copied via a lens system 4 onto the surface of an image carrier 3 which is uniformly charged in advance by a charging means (not shown). The image of M is formed to form an electrostatic latent image. Further, the image forming apparatus 2 is a so-called variable magnification type image forming apparatus that can obtain copies of different sizes from the original document M of the same size by adjusting the position of the lens system 4, etc. ing. Incidentally, the magnification change may be performed stepwise or continuously.

In this case, depending on the copying magnification, the width of the effective image area width A of the image carrier 3 becomes the image area in the illustrated case, and the side edge areas B and C adjacent to the image area is a non-image area.

The illumination device 1 is disposed in the non-image areas B and C of the image carrier 3, and as shown in FIGS. 1 and 2, the illumination device 1 includes a light emitting element 5.6 and a lens. It consists of Corollary 7.8. In this case, an LED is used as the light emitting element 5.6.

The light-emitting elements 5 and 6 are formed of a transparent member into a substantially rectangular parallelepiped shape, and the irradiation side tip portion 9°lO is tapered into a substantially square columnar shape, and the base end portion is provided with a light emitting source. Light emitting chips 11 and 12 are embedded as such. The tip surface of the irradiation side tip portion 9° 10 is formed in a rectangular shape similar to the cross section of the light emitting element 5.6, and minute irregularities are formed on the tip surface by, for example, sandblasting in a matte finish. Transmission and diffusion treated surfaces 13 and 14 are formed which have good transmittance and diffuse light.

Further, the side surface of the irradiation side tip part 9.10 is a curved surface convexly curved outward, and the inner surface thereof reflects the light from the light emitting thiazo 11, 12 onto the transmission diffusion treated surface 13.14. Reflection-treated surfaces 15 and 16 are formed to allow the reflection to occur. The shape of the reflection treated surfaces 15 and 16 is similar to that of the transmission diffusion treated surface 13.
, 14 are formed to have an appropriate curved surface so that the light amount distribution is uniform.

Lens systems 7, 8 are arranged between the light emitting elements 5, 6 and the image carrier 3 configured as described above, and the lens systems 7.8 perform transmission diffusion processing on the light emitting elements 5.6. Surface 13.14
It consists of a convex lens that forms an image on the image carrier 3.

In the above configuration, the illumination device according to the present invention illuminates the surface of the image carrier in the following manner. That is, the light emitting elements 5, 6 and the lens system 7.8 are arranged so that the light emitting elements 5, 6 face the image carrier 3, as shown in FIG. The light beams emitted from the light emitting thiazoles 11 and 12 of the light emitting elements 5 and 6 are irradiated onto the transmission diffusion treated surface 13.14 either directly or after being reflected by the reflection treated surface 13.16. Thus, the transmission and diffusion treated surfaces 13 and 14 diffuse the light flux and shine with high brightness, and also transmit light and become a rectangular secondary light source. The above rectangular shining transmission diffusion treated surface 13.14
is formed on the image carrier 3 via the lens system 7.8. In this way, the rectangular transmission diffusion treated surface 13.
14 is formed on the image carrier 3, and light from other sources does not reach the image carrier 3. Therefore, the surface of the image carrier 3 has a shape similar to that of the transmission diffusion treated surface 15 and 16. The light emitting elements 5, 6 and the lens systems 7, 8 are arranged so that the areas illuminated by the light emitting elements 5, 6 are adjacent to each other without any gaps.
By adjusting the position of , the light intensity distribution on the surface of the image carrier 3 can be adjusted such that no light leaks into the image area and only the non-image areas B and C are uniformly illuminated, as shown in FIG. I can do it,
Non-image areas B and C are uniformly neutralized. Note that the light from the light emitting elements 5 and 6 may overlap at the boundary between the non-image area B and the non-image area C.

In the illustrated embodiment, a case has been described in which the non-image areas B and C exist only on one side of the image area on the image carrier 3, but the non-image areas B and C exist on both sides of the image area on the image carrier 3. Of course, the present invention can be applied even when a non-image area exists.

Furthermore, since the illumination device of the present invention provides illumination in a rectangular shape, the light emitting elements are arranged along the entire length of the image carrier in the axial direction, and the image carrier surface corresponding to the front end and rear end beyond the image area is arranged. It can also be used to erase charges by irradiating light.

Furthermore, in the illustrated embodiment, a case has been described in which the illumination device of the present invention is used to eliminate static from a non-image area caused by a small M magnification. By arranging them and changing the timing of light emission, it is also possible to neutralize any part of the image carrier.

(Effects of the Invention) The present invention has the above-described configuration and operation, and includes forming a rectangular transmission-diffusion treated surface at the irradiation side tip of the light emitting element, and transmitting light from the light emitting source around the irradiation side tip. Since a reflection-treated surface is formed to reflect light on the diffusion-treated surface, and a lens system is placed between the light emitting element and the image carrier, the rectangular shining transmissive-diffusion-treated surface is imaged onto the image carrier by the lens system. As a result, the image carrier can be sharply illuminated only in a shape similar to the rectangular transmission-diffusion treated surface. Therefore, it is possible to reliably prevent the light flux from entering the image area, and also to uniformly eliminate static electricity from the non-image area, thereby preventing deterioration of image quality and wasteful consumption of toner. Further, by adjusting the lens system, it is possible to avoid placing the light emitting element close to the special image carrier, which has the advantage of preventing loss of light amount due to attraction of dust and the like.

[Brief explanation of drawings]

1 to 4 are related to the present invention; FIG. 1 is a perspective view showing a lighting device according to the present invention, FIG. 2 is a horizontal sectional view thereof, and FIG. 3 is a lighting device according to the present invention. FIG. 4 is a graph showing the light intensity distribution characteristics of the illumination device, FIG. 5 and FIG. 6 are related to conventional examples, and FIG. FIG. 6 is a front view showing an image forming apparatus to which the lighting device is applied, and FIG. 6 is a graph showing the light amount distribution characteristics of the lighting device. Explanation of symbols■...Lighting device 3...Image carrier 5.6.
...Light emitting element 7.8...Lens system 9.10...
・Irradiation side tip 11.12... Light emitting chip 13.1
4... Transmissive diffusion treated surface 15.18... Reflection treated surface B, C... Non-image area loincloth -

Claims (1)

[Claims] Irradiation of a light-emitting element equipped with a light-emitting source in an illumination device arranged to face the surface of an image-bearing member and for eliminating unnecessary charges on the image-bearing member by illuminating the image-bearing member. A rectangular transmission-diffusion treated surface for transmitting and diffusing light is formed at the side tip, and a reflection surface for reflecting light from the light emitting source onto the transmission-diffusion treatment surface is formed around at least the irradiation-side tip of the light emitting element. An illumination device comprising a treated surface and a lens system disposed between the light emitting element and the image carrier.