JPS60241604A - 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) Purpose of the Invention This invention is an image forming apparatus such as an electrophotographic copying machine or a printer, in particular a variable magnification type image forming apparatus. The present invention relates to a lighting device used for static elimination.

In image forming apparatuses such as variable-magnification copying machines that can obtain images of various sizes from the same document, the size of the image carrier disposed inside the device is constant, so when changing the magnification, When forming an image using a reduction magnification, a part of the image carrier inevitably (
(If the resulting non-image area is left in a charged state, there will be problems such as consuming excessive toner, contaminating the inside of the apparatus, or producing black streaks on copies.

For this reason, attempts have already been made to irradiate the non-image area with lamps, LEDs, etc. to eliminate static electricity from the open area so that the above-mentioned inconvenience does not occur.

FIG. 3 is a schematic diagram showing the above-mentioned static eliminating means in a known variable-magnification copying machine, in which an optical image of a document M is projected through a lens system 2 onto the surface of a cylindrical photoreceptor 1 rotating around an axis X. to form an image.

At this time, it is assumed that the width of the optical image is D with respect to the effective image width A of the photoreceptor 1, and the areas indicated by symbols B and C are non-image areas. In such a case, in order to neutralize the non-image area, two LEDs 3.5 are placed close to the photoreceptor 1 as shown in the figure, and each LED is selectively turned on as appropriate according to the magnification. do.

Each LED 3.5 has a generally transparent cylindrical shaped part 7,
8, and a convex portion 4 formed in the shape of a convex lens at the tip on the side to be illuminated.
, 6, so that the light beam projected from the internal light source is effectively converged onto the illuminated surface, but a part of the light beam 7' projected from the cylindrical portion 7 does not reach the image area. This may cause unnecessary static elimination by entering the area, resulting in deterioration of copy image quality.

Figure 4 is a graph schematically showing the light intensity distribution of a normal LED as viewed in the axial direction of the photoreceptor. L
It is equipped with an ED. At this time, the harmful light K corresponding to the light beam 7' reaches the image area, which is not preferable.

In order to reduce the influence of such harmful light, by reducing the distance between the LED and the photoconductor, air flows due to the rotation of the photoconductor and the accompanying micro vibrations, which causes the distance between the LED and the photoconductor surface to flow. There is a risk that floating toner, dust, etc. will be induced and adhere to the LED, making it impossible to obtain an effective amount of light and reducing the static elimination effect.

The present invention has been made in order to cope with such a situation, and in particular, when forming an image with a reduction magnification, it is possible to cut the edge of the image area sharply, and also to obtain a sufficient amount of light necessary for static elimination. The present invention relates to an illumination device for an image carrier in a double image forming apparatus.

(2) Structure of the Invention The present invention will be explained below by way of embodiments with reference to the attached drawings.

FIG. 1 is an end view of main parts showing a case where the illumination device according to the present invention is applied to a variable magnification type copying machine similar to that shown in FIG. As in the case of FIG. 1, the width of the effective image area of the photoreceptor; the non-image area; and the image area are shown respectively.

An LED is used as a light emitting element, and parts corresponding to those in FIG. 3 are denoted by the same reference numerals. L.E.
In D3, a reflective surface 7a is formed on a part of the cylindrical portion 7 on the side facing the image area by an appropriate means such as metal foil adhesion, metal vapor deposition, or coating with high reflectance paint. It is.

Therefore, among the light beams projected from the light emitting source, the light corresponding to the above-mentioned light beam 7' is reflected by the reflecting surface 7a and reaches the non-image area side, thereby contributing to the neutralization effect of this portion. Furthermore, since the axis C of the LED 3 is inclined with respect to the axis of the photoreceptor in such a direction that the side on which the reflective surface 7a is not applied approaches the surface of the photoreceptor, as shown in FIG. The resulting light i (Q' in FIG. 2) corresponding to the light iQK on the surface of the photoreceptor is larger than the light amount Q, and the light amount corresponding to the KVC is cut off.

In this way, by forming a reflective surface on a part of the LED, which is a light emitting element, and arranging the LED itself at an angle, it is possible to virtually completely cut out the harmful light flux that enters the image area, and also direct it to the non-image area. Furthermore, since the light beam projected in a direction symmetrical to the harmful light beam is projected at a position close to the center direction of the projected light beam, the light intensity distribution in the projection range on the non-image area side can be improved without adversely affecting the image side. can be strengthened as uniformly as possible.

Therefore, since the necessary amount of light can be obtained without bringing the light emitting element too close to the photoreceptor, insufficient light amount due to adhesion of dust or the like does not occur.

The case where one light emitting element is used has been explained above, but when the reduction magnification is in multiple stages, it is common to use multiple light emitting elements accordingly. When arranging the elements, as shown in Fig. 4, for the light intensity of the peak L, the adjacent light emitting element side (
Since the light amount Q on the side opposite to the image area is relatively small, the arrangement accuracy of the light emitting elements increases the light amount change seen in the axial direction of the image carrier, which may cause a local light amount shortage (6th (see figure).

On the other hand, as mentioned earlier, in the light emitting element according to the present invention, the light tQ' on the adjacent element side is large, and the irradiation range by one element is also limited in shape. It is possible to reduce the shortage of light quantity and to provide as uniform light as possible over the entire non-image area (see FIG. 5).

The present invention has been described above with respect to an electrophotographic copying machine and one using an LED as a light emitting element used therein.
The application of the present invention is not limited to copying machines,
Furthermore, it is obvious that the light emitting element is not limited to LEDVc, and can also be applied to lamps or discharge tubes using filaments.

(3) Effects of the Invention As described above, in the present invention, in an illumination device for removing static electricity from a non-image area of an image carrier that occurs when changing magnification in a variable magnification type image forming apparatus, the light emitting elements are arranged at an angle, and Since a reflective surface is formed on the image area side to deflect the harmful light flux to a non-image area, the irradiation range by the light emitting element can be irradiated in a state closer to uniformity as a whole, and the light flux penetrating into the image area is cut. As a result, the edges of the image can be sharply cut and a high-quality image can be obtained.In addition, by improving the irradiation conditions, there is no need to place the light emitting element close to the special image carrier, which reduces the amount of light caused by the attraction of dust etc. This greatly contributes to preventing loss and obtaining stable images over a long period of time.

[Brief explanation of the drawing]

Fig. 1 is a side view of an embodiment of the light emitting element according to the present invention, Fig. 2 is a light intensity distribution graph of the same as above, Fig. 3 is an explanatory diagram showing the operation of a known copying machine and a static elimination lighting device, and Fig. 4 is one of the same as above. FIGS. 5 and 6 are graphs showing an overview of the total light amount distribution when a plurality of known light emitting elements and the present invention are arranged in a row, respectively. 1. Photoreceptor, 2. Lens system, 3, 5. Light emitting element (L
ED), 7a, 8a...reflective surface. Patent Applicant: Canon Corporation 11A "Fl, Aff!,) 2-' Figure 4 ■ Figure 5 U' (Songgo Yusen) Figure 6 IJCi Tax, Konyoui)

Claims (1)

[Claims] a convex tip that emits most of the luminous flux from the internal light source;
The light emitting element includes a transparent member having a substantially cylindrical part integrally connected to the transparent member, wherein at least a part of the cylindrical part of the light emitting element is formed as a reflective surface, and the light emitting element is connected to the transparent member. An illumination device that is arranged at an angle with respect to the surface to be illuminated so that the reflective surface is located on the side far from the oil to be illuminated.