JPH01129577A - Document reader - Google Patents

Abstract

PURPOSE:To mount a large-sized transparent document on an original platen and to read an image excellently by expanding a lighting area on the original platen more than the projection area of a transparent document projection image. CONSTITUTION:A housing 10, i. e., a lens 4 and a lamp 6 are moved in an optical-axis direction so as to vary the lighting area of lighting light to the platen 7 from a lamp 6. The lens 4 is adjusted in the distance to the lamp 6 with a known focus adjusting ring, etc., so as to set the focus of the lens 4 on the platen 7. When the housing is at a solid-line position, a document F is read and when at a position shown by a two alternate long and two short dashes line, a large-sized document F' is read.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an original reading device capable of reading both reflective originals and transparent originals.

[Prior art]

As a device that can read both reflective and transparent originals,
As shown in FIG. 5, a transparent document table 7 on which a reflective document, such as a book or other ordinary paper that reflects light and whose information is read by the reflected light, is placed;
A Fresnel lens 2 as a field lens is placed closely or close to the document table 7, and the light from a 35 mm slide film is transmitted through the Fresnel lens 2 to direct the imaging light beam of the transparent document F whose information is read using the transmitted light. There is a device that is equipped with a projection device that forms an image on a document table, and reads a reflective document placed on the document table 7 or a transparent document image that has been projected and imaged as described above. In FIG. 5, the reading means includes a support 13 that moves in the direction of the arrow in order to scan the original or original image.
Solid-state image sensor 12 (such as COD) attached to
The optical image of the reflective original is formed on the solid-state image sensor 12 which is also attached to the support 13 (the optical image is converted into an electrical signal), and the image of the transparent original is formed on the original platen. It has a lens 14 that reimages the image. 11
is a lamp attached to the support 13, which is turned off when reading a transparent original, but is turned on when reading a reflective original, illuminating the reflective original from below.

In FIG. 5, the projection device is composed of an illumination lamp 6, a mirror 8, and a lens 9, which converge the emitted light from the lamp 6 below a transparent document such as a 35 mm film supported on a support 5. a projection lens 4 for projecting and forming an image of the bottom of the document illuminated from the back side with the illumination light onto the document table; a mirror 3 for reflecting and directing the light beam from the lens 4 toward the Fresnel lens 2; It is equipped with a Fresnel lens 2. 4
, 5, 6, 8.9 are housed in one housing 10. When placing a reflective original on the document table 7, the Fresnel lens 2 and mirror 3 are removed from the table 7 so as not to cause any trouble. Note that the lamp 6 is turned off when reading a reflective original, and is turned on when reading a transparent original F.

[Problems to be Solved by the Invention] In the apparatus shown in FIG. However, it is not possible to read large formats such as large format films, transparent films for overhead projectors, or the entire length of negative films on which multiple frames of images are printed in series.

[Means for solving problems]

In the invention, a transparent original placed on an original placing table is also read.

At that time, the transparent original is illuminated by the light beam from the illumination section of the projection system, but the illumination area is expanded on the document table 2 to be larger than the projection area of the projected image of the transparent original, and the large-sized original is illuminated. This makes it possible to illuminate the entire area more evenly.

〔Example〕

In the embodiment of the present invention, the angle of 4,5°6 shown in FIG.
, 7 , 8 , 9 , 10 , 1.1 , ], 2
, 13, and 1.4 are used in the same way, so their explanation will be omitted.

In FIG. 1(A), the transparent original F' is placed between the Fresnel lens 2 and the original table 7, but the Fresnel lens 2
may be moved close to the document F' placed on the table 7.

In order to change the area of the illumination area of the illumination light from the lamp 6 to the table 7''2 (this also makes it possible to change the projection magnification of the transparent original F), as described above in FIG. The housing 10, and therefore the lens 4 and lamp 6, are moved in the optical axis direction. In FIG. 1(B), 8 indicates the illumination area of the illumination light from the lamp 6 on the document table when the housing IO is in the solid line position.
9 is the illumination area when the housing 10 is in the position indicated by the two-dot chain line. At this time, in order to align the focus position of the lens 4 on the table 7,
The distance between the lens 4 and the lamp 6 is adjusted by a known focusing ring 4' or the like. When the housing is in the solid line position, the original F can be read, and when it is in the two-dot chain line position, the large original F' can be read.

The above moving mechanism is shown in FIG. Stand 1 on which the housing 10 is placed
5 is provided with a lever 16. The lever 16 is rotatably attached to a hinge stand 17 fixed to the stand 15 via a lever shaft 17. The moving pin 18 provided on the lever shaft 17 is inserted into the elongated hole of the moving plate 19 provided on the housing 10, so that the lever 16
The housing 10 is moved in the direction of arrow 21 in response to the movement in the direction of arrow 20.

In FIG. 3(A), instead of the housing 10, the unit of the mirror 3 and the Fresnel lens 2 is moved parallel to the table 7 in the optical axis direction to change the area of the illumination area of the lamp 6 (therefore, the area of the illumination area of the lamp 6 is changed).
(You can also change the projection magnification.) In FIG. 3(B), reference numeral 22 indicates the area illuminated by the illumination light from the lamp 6 on the document table 7 when the unit is in the solid line position, and 23 is in the double-dashed line position. A large transparent original F' is placed in the area 23, and the original F is projected onto the area 22.

The moving mechanism of the above unit is shown in FIG. The mirror 3 and the Fresnel lens 2 are fixed to a support 24, and the support 24 is mounted on a stand 6 having a guide rail 25 so as to be movable in the direction of the arrow and in the opposite direction. This stand 26 is positioned in the main body 10 by fitting a hole 27 provided therein into a pin or the like provided in the main body 10. Transparent manuscript F'
is placed below the Fresnel lens 2.

By moving the unit, the lens 4 becomes out of focus, but this can be corrected by using the adjustment ring 4' on the pin 1, as explained in FIG.

In the embodiments described above, the illumination area area was changed by changing the optical path length between the lamp 6 and document table 7, but a zoom lens may also be used as the lens 4, and in that case, the illumination area can be changed by zooming the lens. The area area can be changed (therefore, the projection magnification of the original F can also be changed), and there is no need to change the position of the housing 10 or the unit.

In addition, since the area illuminated by the lamp 6 can be expanded on the document table 7 in the above manner, even a large transparent document can be illuminated more uniformly and a good read signal can be formed. Apart from the fact that it is placed and read, there are the following advantages.

That is, the magnification of the projected image of the transparent original F' held by the holder 5 onto the table 7 can be changed. On the other hand, the image reading device uses a large number of integrated arrays of minute photoelectric conversion elements such as CCDs as a reading means, and the image of the transparent original F has a certain periodicity like a printed matter. , or a line, the period of the image of the transparent original F when it is projected onto the image reading device and the period of the reading resolution by the photoelectric conversion element in the image reading device are close values. If moire occurs in the reproduced image, it can be easily eliminated or reduced by simply changing the projection magnification.

Furthermore, by adding an electrical processing means for enlarging or reducing the image of the document F by processing the output signal of the image sensor 12, the range of enlargement or reduction can be increased in synergy with the optical enlargement or reduction function. Can be expanded.

〔effect〕

According to the present invention, a small-sized transparent original is projected onto the original table, and a large-sized transparent original is placed on the original table and illuminated with a wide illumination area, so that good image reading is possible.

[Brief explanation of the drawing]

FIG. 1(A) and FIG. 1(B) are explanatory diagrams of an embodiment of the present invention, FIG. 2 is an explanatory diagram of main parts of an embodiment of the present invention, and FIG. 3(A)
, FIG. 3(B) is an explanatory diagram of another embodiment of the present invention, FIG. 4 is an explanatory diagram of main parts of another embodiment of the present invention, and FIG. 5 is an example of an image reading device to which the present invention can be applied. FIG. 2 is a Fresnel lens, 3 is a mirror, 4 is a lens, 6 is a lamp, and 12 is a solid-state image sensor.

Claims (1)

[Claims] A document table on which both a reflective original and a transparent document can be placed; a first mode for holding a transparent document and projecting an image of the transparent document onto the document table; A projection means that selectively operates in a second mode for irradiating illumination light, and a projection means that reads the reflective original placed on the original table, the transparent original image projected by the projection means, and converts the images into electrical signals. a reading means for converting;
The projector further includes a mirror that reflects the light beam from the illumination section side of the projection means in the direction, a field lens that receives the light beam from the mirror, and means for changing the irradiation area on the document table by the mirror and the field lens. Manuscript reading device.