JPS58195839A - Illuminating device of copying machine of slit exposing type - Google Patents

Abstract

PURPOSE:To use light with simple construction without waste, by disposing a condenser lens on the front face of a cylindrical luminous body so as to condense light in the prescribed range of a photoreceptor. CONSTITUTION:Plural fluorescent lamps 1 are disposed in parallel between a traveling original 5 and a slit 2 and a Fresnel lens 6 directing the longitudinal direction of the lamps 1 is disposed along the front surface of a window 1a formed by the shield 1b of the lamps 1. The projected image of the original 5 is condensed by a photographic lens 3 onto the effective original plane of a photoreceptor 4. The light is thus used with the simple construction without waste.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an illumination device for a slit exposure type copying machine.

The slit exposure method involves moving the subject, such as a document, placed behind the slit, relative to the slit, illuminating the subject surface corresponding to the slit, and then using the photographing lens in front of the slit. This is a method in which partial images of the subject are successively projected onto the surface of a photoreceptor.

An example of this slit exposure method will be explained with reference to FIG.

That is, the cylindrical light emitting body 01 is arranged parallel to the slit 02, and the subject 05 running behind the slit 02
A beam of light is irradiated onto the object, and the image of the subject is captured by the photographic lens 03.
The image is then formed on the photoreceptor 04. The reason why the cylindrical photoreceptor 01 is arranged at an angle with respect to the slid 02 is to prevent the projection light onto the photoreceptor 04 from being obstructed by the cylindrical light emitter. In this arrangement, it is inevitable that the light emitter 01 and the slit 02
The distance between the light beam and the light beam becomes large, and the light flux other than the light beam IsL ends up being dissipated without being used. Therefore, the illuminance on the surface of the subject 05 is low compared to the total amount of light obtained from the light emitter 01, and as is clear from the relational expression: exposure gain/subject surface illuminance x exposure time, the traveling speed of the subject 05 is reduced. The exposure time must be increased. This means that the operating efficiency of the machine deteriorates.

Next, FIG. 2 shows an example in which a reflecting mirror is used to efficiently utilize the light emitted from one light emitter 01.

In the device shown in FIG. 2, a light emitting body 01 is arranged across the width of the paper between a moving subject 05 (hereinafter referred to as a document) and a document 02, and a reflecting mirror 06 is attached to the back of the light emitting body 01. has been done. According to this reflecting mirror 06, the light emitter 01
All the light generated from the image is concentrated on the effective document surface S that can be projected, eliminating unnecessary light dissipation.

However, when this method is applied to large machines that require a larger exposure amount, the reflectors attached to each of the multiple light emitters interfere with each other, making it difficult to maintain the distance between the light emitters and the document. If the number of light emitters is increased, the light will be dissipated and a large amount of illuminance cannot be obtained.

One way to deal with this problem is to attach a shield to the cylindrical light emitter so as to form a window through which concentrated light in a specific direction can be obtained. When arranging multiple such light emitters,
The original surface can be brought into contact with the surface of the document at &:, and relatively efficient irradiation can be obtained.

However, it is not possible to effectively concentrate the light using only the shield method, and irradiation is performed on areas other than the effective document surface.

Note that the effective document surface is the document irradiation surface corresponding to the width of the document slit.

In order to solve the problems of the prior art, the present invention disposes a light condensing means between the document surface and a cylindrical light emitter having a window through which concentrated light can be obtained in a specific direction. It is designed to concentrate the irradiated light onto the effective area of the document surface to be projected, and its purpose is to have a simple structure that allows multiple light sources to be placed close to the document and to utilize light without wasting it. The object of the present invention is to provide a light 111J device.

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 3 and 4.

In the illumination device according to this embodiment, a plurality of fluorescent lamps 1 are arranged in parallel between a traveling document 5 and a slit 2, and a plurality of fluorescent lamps 1 are arranged in parallel along the front surface of a window 1a formed by a shield 1b attached to the fluorescent lamps I. A Fresnel lens 6 oriented in the longitudinal direction of the fluorescent lamp 1 is disposed so that a projected image of the document is formed on the surface of the photoreceptor 4 by the photographing lens 3.

Each pair of Fresnel lenses 3 and Ilk light lamps 1 is arranged closest to the effective document surface S that can be projected onto the photoreceptor 4 so as not to obstruct the optical path. Furthermore, the light rays emitted from each chamber 1a are configured to be concentrated onto the effective document surface S by the Fresnel lens 6.

Note that the effective document surface S is determined by the width of the slit 2 and the distance between the slit 2 and the document 5.

In addition, in this embodiment, a Fresnel lens 6 is used as a light condensing means.
However, it is also possible to use other relatively thin convex lenses.

As is clear from the description of the embodiments above, in the present invention,
Since the exposure light source is a cylindrical light emitting body having a window for obtaining concentrated light in a specific direction, it is possible to bring a plurality of the light emitting bodies as close as possible to the effective document surface. , between the window and the effective document surface, the irradiated light is concentrated on the effective document surface range.Furthermore, in the present invention, the structure is simple, as it is only necessary to arrange the light condensing means in front of the cylindrical light emitting body. The production cost is also low.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of a known illumination device, FIG. 2 is a schematic explanatory diagram of another known illumination device, and FIG. 3 is a schematic explanatory diagram of an illumination device according to an embodiment of the present invention. FIG. 4 is an enlarged explanatory diagram of the main part. 1... Fluorescent light, 'la... Window, 1b... Shield, 2... Slit 13... Photographing lens, 4... Photoconductor, 5... Original, 6... Fresnel lens. Agent: Patent Attorney Nozomi Ehara (1 Ober) Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] In an illumination device for a slit exposure type copying machine in which a cylindrical light emitter having a window for obtaining concentrated light in a specific direction is used as an exposure light source, a plurality of the cylindrical light emitters for exposure are installed and the light is continuously projected onto a photoreceptor. Original partial image force (relative to the resulting effective original surface,
The windows in each of the exposure cylindrical light emitters are arranged to face each other, and a light condensing means is disposed between the window and the effective document surface, and the light condensing means concentrates the irradiated light onto the effective document surface range. A lighting device featuring: