JPS61198224A - Exposing device for copying machine - Google Patents

Abstract

PURPOSE:To make the light quantity distribution of a fluorescent lamp nearly uniform in its lengthwise direction by providing the aperture part of the fluorescent lamp with a light shield member having plural light transmission parts which are narrow at the lengthwise center part and increase in width toward both ends. CONSTITUTION:The light quantity distribution of the fluorescent lamp 12 is corrected nearly uniformly in the lengthwise direction by the light shielding member 19 provided to the fluorescent lamp 12 itself. Consequently, the light shield member 19 never shifts in fitting position to cause the uniformity of luminous flux to deteriorate and a light quantity distribution correcting member need not be provided in the narrow space between a photosensitive body 11 and a subject surface 10, so that assembling operation does not become complicate.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an exposure device for a copying machine using a fluorescent lamp.

2. Description of the Related Art As an exposure device for a copying machine, a fluorescent lamp is often used as a light source, and a known example thereof is shown in FIG.

A fluorescent lamp 2 is disposed below the subject 1fil, and the light is reflected toward the subject plane I by a reflective material 3, and the light from the subject plane 1 is passed through the light intensity distribution correction member 4 through the imaging lens. This is an exposure device configured to irradiate a photoreceptor 6 from a photoreceptor 6.

In such exposure equipment, the characteristic of the fluorescent lamp 2 is that the luminance is different in the longitudinal center of the lamp and in the southern part of the tube, and the distribution is mostly high in the center and low in the ends of the tube, forming a mountain-like distribution. ing.

For this purpose, the fluorescent lamp 2 is
0 distribution has been improved.

On the other hand, the light flux that exposes the photoreceptor through the imaging lens 5 must be uniform in the axial direction of the photoreceptor 6 in order to maintain the uniformity of the copied image.

Therefore, the above-mentioned light intensity distribution correction member 4 for correcting the light intensity distribution of the fluorescent lamp 2 has a slit 4b formed in the plate-shaped body 4σ, and the opening of the slit 4b is narrow in the center and gradually widens toward both ends. By correcting the light amount distribution of the fluorescent lamp 2 described above, the light flux is made uniform in the axial direction of the photoreceptor 6.

Problems to be Solved by the Invention If the relative positions of the fluorescent lamp 2 and the light amount distribution correcting member 4 are misaligned, and the shape of the slit 4b is slightly different, the light amount distribution to the photoreceptor 6, that is, the uniformity of the light flux will be extremely poor. Therefore, it is necessary to make the accuracy of the position and shape of the light amount distribution correction member 40 very strict.

However, in practice, it is difficult to fully satisfy the required accuracy, which has the disadvantage of impairing the uniformity of copied images.

Also, it is necessary to arrange the light amount distribution correction member 4 between the fluorescent lamp 2 and the reflecting member 3, but since the space between the fluorescent lamp 2 and the reflecting member 3 is narrow, the light amount distribution correcting member 4 must be installed. There are drawbacks that can make it difficult.

A slanted means and effect for solving the problem A light shielding member having a plurality of light-transmitting parts narrow at the center in the longitudinal direction and gradually increasing in width toward both sides is provided in the aperture part of the fluorescent lamp to emit light. The light intensity distribution of the lamp is made approximately equal over the length direction.

Embodiment FIG. 1 is an overall perspective view, showing the object surface 10 and the photoreceptor 11.
A fluorescent lamp 12 with a corrected light intensity distribution, a reflective material 13, and an imaging lens 14 are arranged between the fluorescent lamp! The light of 2 is reflected from the object surface by 1° and is irradiated onto the photoreceptor 11 through the imaging lens 14.

That is, the luminous flux of the fluorescent lamp 12 directly irradiates the subject surface 10, which is the original to be copied, and at the same time, the luminous flux of the fluorescent lamp 12 is also reflected from the reflective material 13 and condensed.
The reflected light of 0 is focused on the photoreceptor 11 by the imaging lens 14 and exposed to the photoreceptor 11.

In the wm example, slit exposure is used, and the subject surface 10 or fluorescent lamp 12, reflective material 13, and condensing lens 14 are used.
Self-exposure is performed by scanning either of the two.

The fluorescent lamp 12 has a fluorescent material and a reflective material 16 coated on the inner surface of the glass tube 15, leaving only a part of the coated part, and the uncoated part becomes an aperture part 17. A sixth heater 18 is installed with only a portion left, which improves the temperature stability of the fluorescent lamp.
8 is not attached, faces the aperture section 17, and the luminous flux of the fluorescent lamp exits from the aperture section 17 to the outside.

A light shielding member 19 is attached to the aperture portion 17, and this light shielding member 19 is a thin plate-like elongated member, and slit-shaped openings 20 are arranged at intervals in the longitudinal direction in a direction perpendicular to the longitudinal direction. The width of the opening 200 is narrow at the center in the longitudinal direction and gradually widens toward both sides.

The 1v% light-shielding member 19 has a light-transmitting portion and a light-shielding portion mutually extending in the longitudinal direction, and the width of the light-transmitting portion is narrow at the central portion in the longitudinal direction and gradually increases toward both sides.

Because of this, the light intensity distribution of the fluorescent lamp 12 when the light shielding member 19 is not attached is shown in FIG. 2 (a), and the light intensity distribution of the fluorescent lamp 12 is shown in FIG. It can be corrected so that the illuminance is approximately uniform.

As shown in FIGS. 4 and 5, the fluorescent lamp 12 has a heater 18 attached to the entire circumferential surface of a glass tube 15, and a slit-shaped light-transmitting portion in a portion of the heater 18 facing the aperture portion 17. A light shielding member 19 is formed in which a large number of light transmitting parts 21 are formed at intervals in the longitudinal direction, and a light shielding part 22 is formed between adjacent light transmitting parts 21.
In addition, the width of the light-transmitting portion 210 may be narrow at the center in the longitudinal direction and gradually become wider toward both sides.

Effects of the Invention The light intensity distribution of the fluorescent lamp 12 can be corrected almost uniformly over the length by the light shielding member 19 provided on the fluorescent lamp 12 itself.
Therefore, the mounting position of the light shielding member 19 does not shift and the uniformity of the light flux does not deteriorate, and the photoreceptor 11 and the subject surface 1
There is no need to provide a sight distribution correction member in the narrow space between the front and rear end, and the assembly work does not become troublesome.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing an embodiment of the present invention, FIG. 2 is a front view of a fluorescent lamp, and FIG. 3 is a sectional view taken along the line 1-shoulder in FIG.
FIG. 4 is a front view showing another embodiment of the fluorescent lamp, FIG. 5 is a sectional view taken along the line V--V in FIG. 4, and FIG. 6 is a schematic perspective view of a conventional example. 10 is a subject surface, 11 is a photoreceptor, 12 is a fluorescent lamp, 1
7 is an aperture portion, and 19 is a light shielding member.

Claims (1)

[Scope of Claims] 1. In an exposure device of a copying machine, in which a fluorescent lamp 12 is disposed between a subject surface 10 and a photoreceptor 11 as a light source for illuminating a copied document, an aperture portion 17 of the fluorescent lamp 12 is provided. ,
An exposure device for a copying machine, comprising a light shielding member 19 having a plurality of light-transmitting parts that are narrow at the center in the longitudinal direction and gradually become wider toward both sides. 2. The light shielding member 19 is characterized in that a plurality of openings 20 are formed at intervals in the longitudinal direction in a thin plate-like member attached to the aperture portion 17, thereby forming the light shielding member 19. Copy machine exposure device. 3. The light-transmitting part 21 is attached to the heater 18 that covers the aperture part 17.
and light shielding parts 22 are formed alternately in the longitudinal direction to form the light shielding member 1.
9. The exposure device for a copying machine according to claim 1, wherein