JPS6165212A - Image forming lens of copying machine - Google Patents

Abstract

PURPOSE:To reduce the vertical size of an image forming lens sufficiently by cutting at least either of upper and lower end parts of the lens barrel of the image forming lens arranged having its lens axis almost in level nearly to the peripheral part of the lens body. CONSTITUTION:The upper and lower end parts of the lens barrel 15 are cut to positions closer to the lens axis C than upper ends 11a and 12a, and lower ends 11b and 12b of peripheral edges of large-sized lenses 11 and 12 to form a long circular section. The vertical size L is reduced to irreducible minimum size when a completely circular lens is used, and when the image forming lens 10 is arranged on the optical path 16 of the image formation optical system of the copying machine, the distance between an optical path set above the image forming lens 10 almost in level and the lens axis C of the image forming lens 10 is set to the minimum distance in the use of lenses having the same diameters of large-sized lenses 11 and 12. Similarly, the distance between the image forming lens 10 and equipment 7, etc., can be minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an imaging lens for a copying machine, and more particularly, to an imaging lens for a copying machine in which the lens axis is arranged substantially horizontally and its vertical dimension is shortened. This relates to an imaging lens.

(Conventional Technique #I) Generally, in a slit exposure type copying machine, as shown in FIG. The imaging lens 3 is arranged with the lens axis substantially horizontal in the optical path from the platen glass 1 to the photoreceptor 2. In a copying machine with this kind of structure,
In order to prevent the exposure light from being eclipsed by the imaging lens 3 in the optical path 6 from the scanning mirror 4 to the optical path length adjustment mirror 5, the lower end of the imaging lens 3 is arranged around the photoreceptor 2. For example, the optical path is set so as not to interfere with a charger, etc.).

However, in order to meet the demand for smaller copying machines, it is necessary to arrange the imaging lens 3 and the optical path 6, and the imaging lens 3 and the equipment 7 as close to each other as possible. Therefore, conventionally, the lens barrel that holds the lens body of the imaging lens 3 is made thin, or a so-called oval lens with the upper and lower parts cut off is used as the imaging lens 3.
Attempts have been made to reduce the vertical dimensions of the imaging lens 3.

(Problems to be Solved by the Invention) However, when a thin lens barrel is used as described above, the position of the lens body of the imaging lens 3 is likely to be misaligned, and in the case of an oval-shaped lens, the lens body must be cut into an oval shape. The problem is that it is expensive.

Therefore, the present invention does not cause the above problems, and
It is an object of the present invention to provide an imaging lens for a copying machine whose vertical dimensions can be reduced.

(Means and effects for solving the problems) As described above, the imaging lens of the copying machine of the present invention is arranged with the lens axis substantially horizontal in the optical path from the platen glass to the photoreceptor. , is characterized in that at least one of the upper and lower ends of the M barrel is cut out to the vicinity of the peripheral edge of the lens body. In this way, most of the lens barrels are removed at the upper and lower ends of the imaging lens, and the vertical dimension of the imaging lens becomes approximately the diameter of the lens body, making it sufficiently small.

(Example) Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

Figures 1.2 and 3 show an imaging lens for a copying machine according to an embodiment of the invention. As an example, the imaging lens 10 of this embodiment has four lenses including two large-diameter lenses 11.12 and two small-diameter lenses 13.14 arranged between these large-diameter lenses 11.12. These four lenses 11 to 14 are held in a lens barrel 15. As shown in FIG. 2, which is a sectional view taken along line I-II in FIG. ,
12a and the lower peripheral edges 11b, 12b are cut out to a position closer to the lens axis C, and have an oval cross section.

That is, the upper and lower peripheral portions of the large diameter lenses 11 and 12 are exposed, and the left and right side portions thereof are held by II]1i15. The lens holding structure of the lens barrel 15 at this lens side portion is similar to that of a conventional imaging lens. Further, the small-diameter lenses 13 and 14 are held by the lens barrel 15 at their peripheral portions over the entire circumference, as in conventional imaging lenses.

In the imaging lens 10 of this embodiment having the above configuration, its vertical dimension is the outer diameter of the large diameter lens 11, 12, that is, the minimum dimension that cannot be made any shorter when a completely circular lens is used. There is. Therefore, this imaging lens 1
0 is disposed in the optical path 16 of the imaging optical system of a copying machine as shown in FIG. Lens axis C
The distance between the large diameter lens 11 and 12 can be set to the minimum distance when using a lens having the same diameter as the large diameter lens 11.12. Similarly, the distance between the imaging lens 10 and the equipment 7 can also be set to a minimum.

Note that the large-diameter lens 11.12 is held in the lens barrel 15 at its left and right 1111 parts by the same structure as in the past, as described above, so the large-diameter lens 11.12 The holding position will not be distorted. Furthermore, since the large-diameter lenses 11 and 12 are used in their original circular shape, no special processing is required, and therefore the cost of the imaging lens 10 does not particularly increase.

In the embodiment described above, both the upper and lower ends of the lens barrel 15 are cut out, but even if a lens barrel in which only one of the upper end or the lower end is cut out is used, the vertical dimension of the imaging lens The effect of reducing . Further, in the above embodiment, the lens barrel 15 is the upper peripheral edge 11a of the lens 11.12.
, 12a and the lower peripheral edges 11b, 12b are cut out to a position closer to the lens axis C, but the lens 11.1
Upper peripheral edge 11a, 12a and lower peripheral edge t'allb of 2
, 12b, or the upper edge 11a of these peripheries,
12a and the lower peripheral edges 11b, 12b, the lens barrel 15 may be cut out to a slightly outer side.

(Effects of the Invention) As explained in detail above, according to the imaging lens of the copying machine of the present invention, the distance between the optical path above the imaging lens and the imaging lens, or the distance between the optical path above the imaging lens and the equipment below the imaging lens, Since the distance between the image lens and the image lens can be set as short as possible, the copying machine can be miniaturized.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing an embodiment of the device of the present invention, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, Fig. 3 is an elevational view of the above embodiment device, and Fig. 4 is a conventional FIG. 2 is a side view showing an imaging lens of the copying machine. 1...Platen glass 2...Photoreceptor 3.10.
...Imaging lens 11.12...Large diameter lens 11a
112a... Lens peripheral edge upper end 11b, 12b...
Lens peripheral lower end 15...Mirror rJA16...Optical path C...Lens axis Fig. 4

Claims (1)

[Claims] In the imaging lens of a copying machine, the lens axis is placed approximately horizontally in the optical path from the platen glass to the photoreceptor.
An imaging lens for a copying machine, characterized in that at least one of the upper and lower ends of a lens barrel that holds the lens body is cut out to near the outer periphery of the lens body.