JPH04151643A - Image reader - Google Patents

Abstract

PURPOSE:To read the image of a transmissive original with high light efficiency, to use the light source of low light quantity and to prevent the transmissive original from being damaged by using a bar-like light source and scanning the transmissive original by moving it. CONSTITUTION:The transmissive original A is read by using the bar-like light source 40 fixed as the light source and irradiating the whole surface of the original A with the light from the light source 40 by scanning and carrying the original A in the direction which is almost perpendicular to the longitudinal direction of the light source 40 by a scanning means 42. The transmitted light T of the original A is made incident on an optical path switching means disposed so that it is freely inserted in the optical path of the read light R of the reflected original and the optical path thereof is adjusted. Besides, it is made incident on a photoelectric conversion device. Then, it is read as image information or the image thereof is formed on a prescribed exposure position. Besides, a recording material such as a photosensitive material is exposed. By scanning the original A by the light source 40 by moving it, the image of the transmissive original can be read with the high light efficiency by the light source of the low light quantity. Besides, the image surface is prevented from being damaged caused by the heat of the light source.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is an image reading device that is applicable to printing plate-making devices, copying devices, etc. and is capable of reading original images of both reflective and transparent documents. Regarding.

<Prior Art> In recent years, image reading devices applied to printing plate-making devices and copying devices are capable of reading images not only of reflective originals such as photographs and printed matter, but also of transparent originals such as reversal film and negative film. That is required.

Conventionally, reading of transparent originals in various image reading apparatuses has been performed by a light source unit for transparent originals as shown in FIG. 3, which utilizes an optical system for reading reflective originals.

The light source unit 100 basically includes a light source 102 such as a halogen lamp, a diffusion plate 104, and a housing 106. This is performed by irradiating light A from above and reading the transmitted light of the transparent original A by the optical system of the image reading device 108.

In other words, the light emitted from the light source 102 is transmitted to the diffuser plate 104.
The light is diffused and illuminates the transparent original A placed on the original platen 110, and is transmitted through the transparent original A. The transmitted light T of the transparent original A is
The light source unit 1 passes through the slit 116 of the light source unit 114 (this light source is off) for reflective originals moving in the direction of arrow a.
It is reflected by mirror 118 that moves integrally with light source section 14, and is reflected in a predetermined direction by mirrors 120 and 122 that move at a speed of 172 of light source section 114 in the direction of arrow a. It is converted and processed as image information.

In the illustrated reading device, the light source section 1
14 in the direction of arrow a, the transmitted light T of the transparent original A is sequentially incident on the CCD camera 124, and the image information carried by the transparent original A is read over the entire surface.

<Problem to be solved by the invention> Such a light source unit 100 is used for reading the transparent original A
By applying this, it is possible to read the image of the transparent original A using a unit with an extremely simple configuration by applying a normal optical system for reading reflective originals.

However, in such a light source unit 100, since the transparent original A is irradiated by one light source 102, the entire surface of the transparent original A cannot be irradiated with a uniform amount of light even if it is through the diffuser plate 104. , complex means are required to correct the two-dimensionally distributed light amount,
If this is not done, there is a problem in that the image quality deteriorates, which is particularly a problem in applications that require high image quality, such as plate making equipment.

Furthermore, in order to irradiate the entire surface of the transparent original A with a sufficient amount of light, the light source 102 needs to have a large amount of light. Therefore, the heat generated by the light source 102 may deform the original document A or damage its image surface, and there is also the problem that the efficiency of the light is poor since it is surface illumination.

An object of the present invention is to solve the above-mentioned problems of the prior art, and it is possible to use light efficiently, to apply a light source with a lower amount of light than illuminating the entire surface of the document, and to
Since the light intensity of the light source is distributed one-dimensionally, it is possible to read high-quality transparent original images with a simple method.Furthermore, the image reading device does not deform the original or damage the image surface due to the heat of the light source. Our goal is to provide the following.

<Means for Solving the Problems> In order to achieve the above object, the present invention provides an image reading device capable of reading image information carried on a reflective original and a transparent original. A rod-shaped light source, a scanning means for conveying a transparent original in a direction substantially perpendicular to the longitudinal direction of the rod-shaped light source, and a housing containing the rod-shaped light source and the scanning means, and at least part of a document table for reflective originals. a transmissive original unit placed so as to cover the transmissive original; and a transmissive original unit placed so as to cover the reflective original; Provided is an image reading device characterized in that it has an optical path changing means for making the optical path of the reading light coincide with the optical path of the reading light.

<Operation of the Invention> In the image reading device of the present invention having the above-mentioned predetermined configuration, a fixed rod-shaped light source is used as a light source to read a transparent original, and a scanning device scans a transmissive document in a direction substantially perpendicular to the longitudinal direction of the rod-shaped light source. This is carried out by scanning and transporting a transparent original and irradiating the entire surface of the transparent original with light from a rod-shaped light source. The transmitted light from the transparent original enters an optical path switching means that can be freely inserted into the optical path of the reading light (reflected light from the reflected original) for the reflected original, and the optical path is adjusted, and the subsequent optical path is used to read the reflected original. The light is made to match the optical path of the light and enters a photoelectric conversion device such as a CCD camera and is read as image information, or is imaged at a predetermined exposure position to expose a recording material such as a photosensitive material.

According to the image reading device of the present invention, the rod-shaped light source is used to move the transparent document and scan the document, so compared to the conventional device that uses surface illumination, the image reading device uses a light source with high light efficiency and low light intensity. It is possible to read the image of the transparent original, and there is no deformation of the transparent original or damage to the image surface due to the heat of the light source.

In addition, since the rod-shaped light source is fixed, there is no change in light intensity unevenness caused by scanning a transparent original, and shading correction is easy. Moreover, once shading correction is performed, it can remain in that state for a long period of time. It is possible to read high-quality transparent original images.

<Embodiments> Hereinafter, an image reading device according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

FIG. 1 shows a schematic sectional view of an embodiment of an image reading device of the present invention.

The image reading device 10 shown in FIG.
This device is capable of reading image information carried on both reflective originals such as originals and transparent originals such as negative film and reversal film, and basically consists of a reading device main body 12 and this reading device. It is composed of a transparent original unit 16 that is detachably provided so as to cover at least a part of the original platen 14 on the upper surface of the main body 12, and a transparent original unit 16 that is detachably provided so as to cover at least a part of the original table 14 on the upper surface of the main body 12. An optical path switching mirror 18 is provided as an optical path switching means for adjusting the optical path (dotted chain line in FIG. 1).

The basic configuration of the reading device main body 12 is the same as that of a normal reflective original reading device, and includes a light source section 20 and a mirror unit 2.
2, a CCD camera 24, and an optical path switching mirror 18.
It is composed of.

The light source section 20 includes light sources 26a and 26 for reflective original reading.
b, and a reflector 28, and is configured to be movable in the scanning direction indicated by arrow a. Further, below the light source section 20, a mirror 30 that moves integrally with the light source section 20 is arranged.

The mirror unit 22 includes two mirrors 32a and 32b.
It moves in the same direction at 1/2 the speed of the light source section 20 and reflects reflected light R (reading light, double-dashed line in Figure 1) from the reflective original in a predetermined direction. .

The reflected light R reflected in a predetermined direction by the mirror unit 22 is incident on the CCD camera 24 . The CCD camera 24 has an imaging lens and a CCD optical element, and reflects reflected light R (transmitted light T) that is incident on the CCD camera 24.
) is photoelectrically converted and processed as image information.

In such an image reading device 10, when reading a reflective original, the transparent original unit 16 is removed, the reflective original is placed at a predetermined position on the original table 14 with the image surface facing downward, and then the reflective original is placed in a predetermined position on the original platen 14 with the image surface facing downward. The document table 14 is covered with a document holder, and while the light source unit 20 is moved in the direction of arrow a, the reflected document is illuminated with light emitted from the light sources 26a and 26b, and the entire surface of the document is scanned. Reflected light R from the reflective original passes through the slit 34 of the reflector 28 and is reflected in a predetermined direction by the mirror 30 and mirror unit 22, and is reflected by the CCD.
The light enters the camera 24, undergoes photoelectric conversion, and is processed as image information.

In the image reading device 1o according to the present invention, an optical path switching mirror 18 that can be inserted into the optical path of the reflected light R of the reflective original is provided.
will be deployed.

The optical path switching mirror 18 is connected to the transparent original unit 1 which will be described later.
6 is reflected in a predetermined direction, the optical path of the subsequent transmitted light T is made to coincide with the optical path of the reflected light R, and the transmitted light T is made to enter the CCD camera 24.

In the illustrated example, this optical path switching mirror 18 is
6, and is configured to be freely rotatable in the direction indicated by the arrow 6, and when reading a reflective original, is evacuated outside the optical path of the reflected light R shown by the dotted line in FIG. 1, and allows the reflected light R to enter the CCD camera 24. When reading a transparent original, the reflected light R shown by the solid line in Figure 1
It reflects the transmitted light T in a predetermined direction whose optical path coincides with the optical path of the reflected light R, and allows the transmitted light T to enter the CCD camera 24 along a predetermined optical path.

The method of inserting and retracting the optical path switching mirror 18 into the optical path is not limited to the method of rotating around the support shaft 36 as shown in the example shown, but it can be configured to be freely inserted into the optical path by applying a link mechanism. Various known means such as these can be applied.

In the image reading apparatus 10 of the present invention, the transparent original unit 16 is attached when reading a transparent original.

The transparent original unit 16 is placed at a predetermined position on the original platen 14, and consists of a housing 38, a rod-shaped light source 40, and a transparent original scanning means 42 disposed within the housing 38. It is composed of

The housing 38 is a light-shielding case, and is provided with a lid 44 on the top for loading a transparent original into the scanning means 42, and a slit 46 on the bottom for allowing the transmitted light T to pass through.

The slit 46 is a slit having a longitudinal direction perpendicular to the plane of the paper in FIG.
The light flux of the transmitted light T of the transparent original is adjusted according to the position of the transparent original, and the light T is transmitted through the transparent original.

In the illustrated transparent original unit 16, the housing 38 is configured to cover the entire surface of the original platen 14 to block light; however, the present invention is not limited to this, and the optical path switching mirror 18, the rod-shaped light source 40, Depending on the position of the slit 46 and the like, it may be configured and arranged so as to cover at least a portion of the document table 14. However, in this case, in order to prevent light from the outside from entering the reading device main body 12 and causing flare, places that are not covered by the housing 38 (transparent original unit 16) of the original table 14 are required. It is preferable to take various light shielding measures.

The rod-shaped light source 40 irradiates a transparent original to generate transmitted light, and is provided at the top of the housing 38 with a first longitudinal direction.
It is placed perpendicular to the plane of the drawing. In addition, the rod-shaped light source 4
0 is provided with a glue deflector 41 for efficiently emitting irradiated light in a predetermined direction.

In the image reading device 10 of the present invention, by having such a fixed rod-shaped light source, it is possible to read images with higher efficiency and lower light intensity than conventional devices that use enclosed light. Furthermore, since the light source is fixed, there is extremely little variation in the amount of light even when reading is performed, and if shading correction is performed first, there is no need to perform correction again over a long period of time.

The rod-shaped light source 40 is not particularly limited, and may be a fluorescent lamp, a rod-shaped halogen lamp, or a number of other sources as long as it can illuminate the entire width of a transparent document of maximum applicable size in a direction substantially perpendicular to the direction of arrow C, which is the scanning direction. Any of various known rod-shaped light sources can be applied, such as a combination of a point light source and a fiber array.

A transparent original is conveyed below the rod-shaped light source 40 in the direction of arrow C, that is, in a scanning direction substantially perpendicular to the longitudinal direction of the rod-shaped light source 40, and the entire surface of the original is scanned by irradiating the transparent original with the irradiation light of the rod-shaped light source 40. Scanning means 42 are arranged.

A schematic plan view of the scanning means 42 is shown in FIG. The scanning means 42 includes a holder 48 that holds the transparent original A, and a driving bag N50 that scans and conveys the holder 48 in the direction of arrow C.
It has the following.

The holder 48 is made of two glass plates that sandwich the transparent original A, or a frame thereof, a frame that can fix the transparent original A, or the like.
The sheet-shaped transparent original A is capable of transmitting the irradiated light from the rod-shaped light source 40 and can be held in a flat shape, and may have various forms depending on the drive device 50.

Moreover, it is of course possible to use an object having a frame body, such as a so-called slide.

As shown in FIG. 2, the drive device 50 includes a roller 52
and 54; belts 56 and 58 stretched across both ends of rollers 52 and 54; motor 60;
The holder 48 holding the transparent original A is attached to the belt 56 by the fixing member 62.
and 58 in a detachable manner. In such a drive device 50, the motor 60 rotates the roller 54 to convey the holder 48 in the direction of arrow C via the belts 56 and 58.

There are no particular limitations on the shapes of the belts 56 and 58 and the fixing member 62, and they may be configured to reliably support and scan and convey, depending on the shape of the holder 48 and the like.

The drive device 50 is not limited to one that uses the illustrated example of a belt and rollers, but may also include one that uses a sprocket gear and a chain, one that uses a rack and pinion, one that uses a drive shaft and a nut, and one that uses a roller pair. Any of various known conveying means can be used as long as it has a structure that allows the irradiated light from the rod-shaped light source 40 to pass through the transparent original A at the passing position.

Further, in the scanning means 42, the holder 48 is not limited to being configured to be detachably attached to the drive device 50, but may be fixed to the drive device 50.

Note that in the image reading device 10 of the present invention, the scanning means 42 is not limited to having the holder 48; for example, a pair of rollers disposed sandwiching the passing position of the transmitted light T is provided, and this pair of rollers is A configuration in which the transparent original A is directly provided to the drive device may be used, such as a method in which the transparent original A is directly held and conveyed.

When reading an image of a transparent original A using the image reading apparatus 10 of the present invention, first, the transparent original unit 16 is placed at a predetermined position on the original platen 14.

Next, the lid body 44 is opened, the holder 48 supporting the transparent original A is placed on the belts 56 and 58, and the fixing member 62 is placed on the belts 56 and 58.
After fixing, the lid body 44 is closed.

When the operator selects the transparent original mode of the image reading device 10, the optical path switching mirror 18 moves to the solid line position in FIG. Move to a position other than the optical path of T. Note that the selection of the transparent original mode may be configured to be automatically performed by placing the transparent original unit 16 at a predetermined position on the original platen 14.

Next, when the switch is turned on, the rod-shaped light source 40 lights up, and after a predetermined period of time, the holder 48 is moved by the drive device 50.
is scanned and conveyed in the direction of arrow C. When the holder 48 moves below the rod-shaped light source 40, the light from the rod-shaped light tA40 illuminates the transparent original A held by the holder 48 and is transmitted therethrough. Note that at this time, the light sources 26a and 26b for the reflective original are turned off.

The transmitted light T of the transparent original A passes through the slit 46 while its luminous flux is adjusted, and is reflected by the optical path switching mirror 18, thereby being reflected in a predetermined direction, making the optical path the same as that of the reflected light R from the reflective original. , enters the CCD camera 24 along a predetermined optical path, undergoes photoelectric conversion, and is read as image information.

By conveying the holder 48 in this manner, the entire surface of the transparent original A held therein is scanned with the light from the rod-shaped light source 40, and the transmitted light T is sequentially incident on the CCD camera 24 and read, and the transmitted light T is Image information in original mode is read.

In the image reading device 10 of the present invention, the placement position of the transparent original unit 16 on the original table 14 is a predetermined position defined by the arrangement positions of the linear light source 40, the slit 46, and the optical path switching mirror 18. There needs to be.

Therefore, it is preferable that various positioning means be provided on the upper surface of the housing 38 and/or the reading device main body 12 so that the transparent original unit 16 can be easily placed in a predetermined position. There is no particular limitation on the positioning means, and any known means such as a positioning bin, a corresponding hole, a protrusion, a groove, or even a visual mark can be applied.

In addition, the transparent original unit 16 is not limited to one that is configured to be removably attached to the reading device main body 12, and the transparent original unit 16 can be reflected by various known methods, such as providing a reflective original insertion slot on the side surface of the transparent original unit 16. A transparent document unit 16 is configured so that the document can be placed at a predetermined position on the document table 14.
The reading device main body 12 and the reading device main body 12 may be integrally configured.

Furthermore, although the optical path lengths of the transmitted light T and the reflected light R must basically be the same, for example, an optical path length adjusting means such as a lens may be provided in the optical path of the transmitted light T to miniaturize the device. Alternatively, the CCD camera may be provided with a zoom function or the like so that the optical path length can be adjusted.

Although the image reading device according to the present invention has been described in detail above, the present invention is not limited thereto (and various changes and improvements may be made without departing from the gist of the present invention). Of course.

<Effects of the Invention> As explained in detail above, the image reading device of the present invention uses a rod-shaped light source to move the transparent original and scan the original, so compared to the conventional reading device that uses surface illumination, , it is possible to read images of transparent originals with high light efficiency, a light source with low light intensity can be used, and the transparent originals will not be damaged.

In addition, rod-shaped light sources require low light intensity and are fixed, so there is little change in the light intensity distribution etc. due to use, and shading correction is easy. It is possible to read high-quality transparent original images.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an example of an image reading device according to the present invention. FIG. 2 is a schematic plan view showing an example of the scanning means of the image reading device shown in FIG. FIG. 3 is a schematic cross-sectional view of a conventional image reading device. Explanation of symbols 10.108...Image reading device, 12...Reading device main body, 14.110...Original table, 16...Transparent original unit, 18...Optical path switching mirror 20 114... - Light source section, 22...Mirror unit, 24 124...CCD camera, 26a, 26b, 102...-Light source, 28.41...Reflector, 30.32a, 32b, 118° 120 122... Mirrors 34, 46, 116...Slit, 36...Spindle, 38.106...Housing, 40...Bar-shaped light source, 42...Scanning means, 44...Lid, 48...・Holder, 50...Transportation device, 52.54...Roller, 56.58...Belt, 60...Motor, 62...Fixing member, A...Transparent original, T... Transmitted light, R...Reflected light FIG, 1

Claims (1)

[Claims] (1) An image reading device capable of reading image information carried on a reflective original and a transparent original, which includes a rod-shaped light source for reading the transparent original, and a transparent original in a direction substantially perpendicular to the longitudinal direction of the rod-shaped light source. a transmissive original unit that has a housing that includes a scanning means for transporting, the rod-shaped light source, and the scanning means, and is placed so as to cover at least a part of a document table for reflective originals; The apparatus is characterized by comprising an optical path changing means that is freely inserted into the optical path of the reading light and makes the optical path of the transmitted light emitted from the rod-shaped light source and transmitted through the transparent original coincide with the optical path of the reading light of the reflective original. image reading device.