JPH02203668A - Picture reader - Google Patents

Abstract

PURPOSE:To read picture information on a transmission type original and a reflection type original with high accuracy by making the optical path from the transmission type original and the reflection type original whose read position differs from each other till a CCD camera identical through the adjustment. CONSTITUTION:The reader is a picture reader able to read freely photoelectrically the picture information on the transmission type original and the reflection type original whose read position differs from each other and in this case, a 1st read means 112 reading the transmission type original S1 and a 2nd read means 114 to read the reflection type original S2 are built in a single CCD camera 108 and the CCD camera 108 is freely movable along the optical axis of a transmission light L1 and a reflected light L2 under the action of a moving means 150. Thus, even when the transmission type original and the reflection type original are located at a different position, the picture information on them is surely read with high accuracy.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image reading device, and more specifically, an image reading device that reads light containing image information carried on a reflective original through an imaging optical system. 1 reading means, and a second reading means for reading light including image information carried on a transmission type original through the imaging optical system.
reading means is incorporated into a single camera, and the camera is displaced along the optical axis corresponding to each document, so that the optical path length of light containing image information derived from each document can be adjusted to be the same. The present invention relates to an image reading device.

[Background of the invention] For example, in the field of printing plate making, streamlining of work processes,
2. Description of the Related Art Image scanning, reading and reproducing systems that electrically process image information carried on a document to create a film original are widely used for the purpose of improving image quality.

An image scanning reading and reproducing system basically consists of an image reading device and an image reproducing device.

In this case, the image reading device illuminates the document being conveyed in the sub-scanning direction in the main scanning direction using illumination means, and the image reading means reads the reflected light or transmitted light and converts it into an electrical signal. On the other hand, the image reproducing device performs arithmetic processing such as gradation correction and edge enhancement according to plate-making conditions on the image information photoelectrically converted by the image reading device, and records and reproduces the image on a record carrier such as film. Note that this recording carrier is developed by a predetermined developing device and used as a film original for printing or the like.

In general, this type of image reading device is divided into two types: a transmitted light type that reads image information carried on a transparent film, etc., and a reflected light type that reads image information on printed materials, etc., depending on the use and purpose. It is manufactured separately, and the types of documents that can be read are limited by its format. Therefore, it is difficult to universally read many types of documents with one image reading device, and there is a demand for an image reading device that integrates the reflected light type and transmitted light type image reading devices. has been done.

However, various problems have been pointed out in the past when integrating this type of reflected light type and transmitted light type. That is, when reading a reflective original such as a printed matter, the reflective original is placed on the original platen and the original platen is conveyed in the sub-scanning direction while a light-transmitting presser glass is placed on the reflective original. At the same time, reflected illumination light is irradiated in the main scanning direction to read the reflective original. Here, it has been pointed out that the reflective original comes into close contact with the presser glass, which tends to cause local density changes and streaky dark areas. It is possible to think of things that form the .

However, if a presser glass having such an uneven surface is used for reading a transmission-type original such as a film, there is a risk that the transmitted illumination light will be refracted by the uneven surface and will not reliably enter a CCD camera or the like. . For this purpose, the transmission type original is placed on the presser glass having the uneven surface, and a presser glass with anti-reflection means is placed on the transmission type original, so that the transmitted illumination light is diffused. A device that irradiates the transmission type original is considered. Thereby, it is possible to perform the reading operation of the transmission type original with high precision without being affected by the uneven surface.

Incidentally, in this case, when attempting to read a reflective original and a transmissive original with a single CCD camera, the distances (optical path lengths) on the optical paths from the reflective original and the transparent original to the CCD camera, respectively, vary. Resulting in. As a result,
The image formation positions are different for reflective and transmissive originals, making it impossible to reliably image light containing image information on the CCD, making it difficult to obtain clear and highly accurate image information. It ends up.

[Object of the Invention] The present invention has been made in view of the above points, and includes first and second reading means for photoelectrically reading light containing image information carried on a reflective original and a transmissive original. is incorporated into a single camera, and the camera is configured to be movable along the optical axis in accordance with the positions of the reflective original and the transmissive original, so that the reflective original and the transmissive original are different from each other. It is an object of the present invention to provide an image reading device that can read image information carried on each image with high precision and reliability even if the image information is located at different positions.

[Means for Achieving the Object] In order to achieve the above object, the present invention provides a main image reading device capable of photoelectrically reading image information carried on a transmissive original and a reflective original, each having a different reading position. a first reading means for reading image information along the main scanning line of the transmissive original through the imaging optical system; and a first reading means for reading the image information along the main scanning line of the reflective original through the imaging optical system. a second reading means for reading through the system, and the first reading means, the second reading means, and an imaging optical system are integrated in correspondence with the reading positions of the transmission type original and the reflection type original. It is characterized by comprising a moving means that moves forward and backward along the optical axis.

[Embodiments] Next, preferred embodiments of the image reading apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1, reference numeral 30 indicates an image reading device according to this embodiment. The image reading device 30 includes a document table 32 on which a document is set, a conveyance mechanism section 34 that conveys the document table 32 in the direction of the arrow, and a conveyance mechanism section 34 that scans the document conveyed in the sub-scanning direction. It basically consists of an image reading section 36. In this case, the transport mechanism section 3
4 is arranged on the first casing 38, and the image reading section 3
6 is provided inside the second casing 40 placed on the first casing 38 . Note that an opening 42 is defined on one side of the second housing 40 to allow the document table 32 to pass therethrough.

First, the transport mechanism section 34 will be explained. Horizontal and parallel guide bars 442 and 44b are disposed on the upper surface of the first housing 38, and these guide bars 44
Both ends of a and 44b are supported by support stands 46 and 48 on the first housing 38. Moreover, the guide bar 44a
, 44b, a ball screw 50 connects the supports 46 and 4.
The ball screw 50 is rotatably driven by a drive motor 52 provided within the first housing 38 .

A document table 32 holding a transmissive document S1 or a reflective document S2 carrying image information is movably supported by the guide bars 44a and 44b.

That is, as shown in FIGS. 1 and 2, the document table 3
2 is a base 54 and a base glass 56 on which the reflective original S2 is placed.
and a first presser cover 5 that can be opened and closed and has a presser glass 57 attached thereto.
8 and a second presser cover 64 to which a mask member 60 and a presser glass 62 are attached, which are placed over the transmissive original S when the transmissive original S is placed on the presser glass 57.

A hollow portion 66 into which a prismatic body described later is inserted into the base 54.
is defined, and an opening 68 for guiding transmitted illumination light, which will be described later, to the transmission type document S1 via the base glass 56.
is defined. Further, a pin member 70a170b is planted in the base 54 so as to be oriented vertically upward, while a hole 7 in the first presser cover 58 through which the pin member 70a, 70b is inserted.
2a and 72b are drilled. An opening 60a is formed in the center of the mask member 60, and a hole 73a1 into which the pin members 70a and 70b are fitted is formed at one end edge of the mask member 60.
73b is provided. In addition, the inner side of the holding glass 57,
That is, the uneven surface 5 is formed on one side facing the reflective original S2.
7a, and an antireflection film 62a is provided on at least one side of the holding glass 62 (see FIGS. 6 and 7). Further, hook bodies 74a and 74b made of a resin material are engaged with both longitudinal ends of the second presser lid 64, and handles 76a and 76b are fixed to the hook bodies 74a and 74b.

The transmitted illumination means 83 is surrounded by a hollow prismatic body 85 whose both ends are supported on the first casing 38 by support stands 84a and 84b. The prismatic body 85 defines an opening 86 for guiding transmitted illumination light, which will be described later. The transmitted illumination means 83 is housed in the prismatic body 85, and the transmitted illumination means 83 is composed of a halogen lamp, a xenon lamp, etc., and has a light source 88 that outputs transmitted illumination light L1, and a light guide at both ends. and an optical fiber bundle 92 configured by bundling a large number of optical fibers 90 held by members 89a and 89b. Further, a cylindrical rod lens 94 is disposed within the prismatic body 85 to condense the transmitted illumination light L1 guided by the optical fiber bundle 92 into a line. The transmitted illumination light L1 focused by the rod lens 94 is guided to the transmitted original document SI through a hairline mirror 96. In this case, the hairline mirror 96 is set so that the transmitted illumination light L+ is obliquely incident on the transmission type original SI at a predetermined angle. Hey,
In fact, the hairline mirror 96 is arranged so that the angle between the transmitted illumination light Ll and the normal to the base glass 56, that is, the virtual perpendicular P, is approximately 30°.

On the other hand, inside the second casing 40 is a reflecting mirror 102 that horizontally reflects the transmitted illumination light L1 that has passed through the transmissive original S1 at a predetermined inclination angle, and the transmitted illumination that is reflected in the horizontal direction by this reflective mirror 102. CCD camera 1 as an image reading mechanism that reads light L1 and reflected illumination light to be described later
08 is displaceably provided.

The CCD camera 108 includes a casing 110, in which a first reading means 112 and a second reading means 114 are arranged. Furthermore, casing 11
An imaging lens 116 as an imaging optical system is attached to one end of the casing 110, and the transmitted illumination light L1 and the reflected illumination light transmitted through the imaging lens 116 are stored in the casing 110 for the first reading. Means 112 and second reading means 1
14 is installed.

The optical path switching means 118 has a reflector 120, and a rotating shaft 122 is attached to one side of the reflector 120. The rotating shaft 122 is substantially rotatably supported on a base 124, and a rocking plate 12 is attached to an end of the rotating shaft 122.
Attach one end of 6. The swing plate 1 is mounted on the base 124.
An actuator, for example, a linear solenoid 12g is fixed close to the 26 side, and this linear solenoid 128
The large diameter portion 132 of the rod 130 extending from the rocking plate 12
6. Here, a coil spring 134 is externally mounted on the rod 130, and when the linear solenoid 128 is deenergized, the coil spring 134 is
The rod 130 presses the swinging plate 126 through the elastic force of 4, thereby holding the reflector 120 oriented in the horizontal direction. On the other hand, when the linear solenoid 128 is driven, the rod 130 is displaced inward and the reflector 120 comes into contact with the stopper 136, so that it is positioned and held at an angle of 45 degrees with respect to the vertical direction.

Above the reflector 120 is a line sensor for transmitted illumination light, such as a CCD 138, which constitutes the first reading means 112.
are arranged so as to extend in parallel along the main scanning line of the transmission type document S1.

The second reading means 114 includes first and second reflective mirrors 140a and 140b disposed corresponding to both edges of the main scanning line of the reflective original S2, and the reflective mirror 140a
, 140b are positioned at an angle of 45 degrees with respect to the vertical direction. Respective reflective mirrors 140a.

Line sensors for reflected illumination light, such as CCDs 142 and 144, are arranged above 140b. Further, a CCD 146, which is a line sensor, is also provided on the optical path of the reflected illumination light passing through the gap between the first and second reflecting mirrors 140a and 140b.

Therefore, the reflective original S2, which has larger dimensions than the transmissive original S, actually has three CCIs) 142.144 and 1.
It is configured to read in pieces over 4G.

Next, the CCD camera 108 is moved back and forth along the optical axis of the transmitted illumination light L1 and the reflected illumination light via the moving hand &150. That is, as shown in FIGS. 4 and 5, the moving means 150 includes a bottom plate 152 fixedly installed inside the second casing 40, and horizontal and mutually parallel guides are provided on the bottom plate 152. The bars 154a and 154b are supported by support plates 156 and 158 erected on the bottom plate 152. Further, the guide bars 154a, 154b
The ball screw 160 is parallel to the support plate 156, 158.
In this case, the ball screw 160 is disposed on the support plate 15.
It is rotationally driven by a drive motor 162 fixed to 8. A casing 110 of a CCD camera 108 is attached to the guide bars 154a, 154b and the ball screw 160.
Guide portions 164a and 164b formed in the guide portions 164a and 164b are supported so as to be movable in the direction of arrow A and the opposite direction.

On the other hand, within the second casing 40 is provided a reflective illumination means 170 that irradiates reflective illumination light, which will be described later, onto the reflective original S2.

In this case, the reflected illumination means 170 includes a light source 172 that outputs reflected illumination light L2, and a holding member 174a whose both ends are light guiding.
, 174b.
The optical fiber bundle 178 includes a curved optical fiber bundle 178 formed by bundling the optical fiber bundles 178 and cylindrical rod lenses 180 that condense the reflected illumination light L2 guided by the optical fiber bundles 178 into a line shape. At this time, the position of the holding member 174b is selected so that the illumination angle α between the reflected illumination light L2 emitted from the holding member 174b and the virtual perpendicular P perpendicular to the document table 32 is about 15°. The reflected illumination light L2 collected by the rod lens 180 is reflected by the reflective original s2, and then enters the CCD camera 108 via the reflective mirror 102. At this time, the CCD camera 108 is disposed at a position where it can read the reflected illumination light L2 reflected at a reading angle β of about 30 degrees with respect to the virtual perpendicular P through the reflection mirror 102.

The image reading device according to this embodiment is basically configured as described above, and its operation and effects will be explained next.

When reading the transmission original S1, as shown in FIGS. 4 and 5, the CCD camera 108 is displaced in the direction of arrow A, and the CCD camera 108 is positioned at the position shown by the solid line in the drawings. That is, when the ball screw 160 is rotated in a predetermined direction under the action of the drive motor 162 constituting the moving means 150, the guide portion 16 into which the ball screw 160 is fitted is rotated.
4a.

The casing 110 moves in the direction of arrow A via 164b. Then, when the CCD camera 108 reaches a predetermined position, the drive motor 162 is deenergized.

Next, close the first presser cover 58 of the document table 32 and close the hole 7.
2a,? Pin members 70a and 70b are fitted to 2b. Next, the mask member 60 is placed on the holding glass 57, and the opening 60 formed in the mask member 60 is opened.
A transmissive original S1 is placed at a.

Furthermore, hold the handles 76a and 76b and press the second presser lid 64.
is placed on the mask member 60, and this second presser lid 64 is placed on the mask member 60.
The transmission original S1 is held between the presser glass 62 of the first presser cover 58 and the presser glass 57 of the first presser cover 58 (see FIG. 6). Here, the document table 32 is conveyed in the six directions of arrows under the action of the drive motor 52 and moved to a predetermined portion of the image reading section 36 .

The document table 32 holding the transparent document S1 is connected to the image reading unit 36.
When the transmissive original S1 reaches a predetermined portion, the reading operation of the image information carried by the transmissive original S1 is started. That is, the transmitted illumination light outputted from the light source 88 passes through the optical fiber bundle 92, is condensed by the rod lens 94, is reflected by the hairline mirror 96 at a predetermined angle tilted with respect to the vertical upward direction, and is reflected by the aperture. The document 86 is guided to the document table 32 . The transmitted illumination light is a base glass 56.
The transmission original S1 is then irradiated through the presser glass 57 in the main scanning direction perpendicular to the arrow.

In this case, as shown in FIG. 6, the transmitted illumination light enters the presser glass 57 as diffused light, and the image information carried on the transmission type document S1 is captured without being affected by the uneven surface 57a. Extract it as an optical signal. Furthermore, the image information as this optical signal is transmitted to the anti-reflection film 6 of the presser glass 62.
2a to have directivity, and the reflecting mirror 10
2 and is reflected in the horizontal direction and guided to the CCD camera 108.

At this time, the optical path switching means 11 in the CCD camera 108
8, the linear solenoid 128 is energized to displace the rod 130 inwardly against the elastic force of the coil spring 134. Therefore, the pressing action on the swing plate 126 is released, and the reflector 120 swings vertically downward due to its own weight and comes into contact with the stopper 136, and the reflector 120
is positioned at an angle of 45 degrees with respect to the vertical direction. Therefore, the transmitted illumination light L1 guided to the CCD camera 108 side passes through the imaging lens 116, reaches the reflector 120, and is reflected vertically upward by the reflector 120.

Thereby, the transmitted illumination light is photoelectrically read via the CCD 138, which is the first reading means 112.

During this time, the document table 32 is being transported in the sub-scanning direction (in the direction of the six arrows) under the action of the drive motor 52.

As a result, the transmission type document S1 is illuminated two-dimensionally by the transmission illumination light, and the image information is extracted and displayed on the CCD.
138. After the reading operation is completed, the drive motor 52 is rotated in the opposite direction to move the document table 32 to a predetermined position.

Next, when reading the reflective original S2, first,
The reflector 120 is displaced to the position shown by the two-dot chain line in FIG. That is, by deenergizing the linear solenoid 128, the rod 130 projects outward through the elastic force of the coil spring 134, and this rod 130 presses the swing plate 126. Therefore, the rotating shaft 122 rotates by a predetermined angle, and the reflector 120 attached thereto swings vertically upward by a predetermined angle to be positioned.

Further, by driving the moving means 150, the CCD camera 108
Distance in the opposite direction to arrow A! (see Figures 4 and 5). That is, the ball screw 160 is rotated in the opposite direction to that described above via the distance motor 162, and the casing 110 into which it is fitted is moved in the opposite direction to the arrow A. Then, when the CCD camera 108 reaches the position indicated by the two-dot chain line in FIGS. 4 and 5, the driving motor 162 is deenergized. Here, the moving distance β of the CCD camera 108 is, of course, set in accordance with the difference in optical path length between the reflective original S2 and the transparent original Sl, as shown in FIG.

On the other hand, the second presser cover 64 is removed from the base 54 via the handles 76a and 76b, and the transmission original S1 and mask member 60 are removed from the presser glass 57.

Next, the first presser lid 58 is lifted vertically upward. In this state, after placing the reflective original S2 facing upward on the base glass 56, the first presser cover 58 is closed and the bin member 70a is inserted into the hole 72a172b of the first presser cover 58.
70b is inserted. Therefore, the presser glass 57 can press the reflective original S2, and the uneven surface 57a formed on the presser glass 57 can prevent the reflective original S2 from coming into close contact with the reflective original S2 (see FIG. 7). and,
The document table 32 is conveyed in the direction of the arrow under the action of the drive motor 52 and moved to a predetermined portion of the image reading section 36 .

When the document table 32 reaches a predetermined part of the image reading section 36,
The reading operation of the reflective original S2 is started.

That is, the reflected illumination light L2 output from the light source 172 passes through the optical fiber bundle 178, is focused by the rod lens 180, and is guided to the document table 32. Then, the reflected illumination light L2 irradiates the reflective original S2 in the main scanning direction through the presser glass 57, and image information is extracted as an optical signal (see FIG. 7). This image information as an optical signal is reflected obliquely from the presser glass 57 and then guided to the second reading means 114 in the CCD camera 108 via the reflection mirror 102.

As shown in FIG. 3, in the second reading means 114, the reflected illumination light L2 is divided into three parts, and the reflected illumination light L2 from both edges of the main scanning line of the reflective original S2 is divided into three parts. The light is reflected vertically upward by 140a and 140b and guided to CCDs 142 and 144. Further, the reflected illumination light L2 from the middle part of the main scanning line of the reflective original S2 is directly irradiated onto the CCD 146. By this, c CD
All image information in the main scanning direction of the reflective original S2 is photoelectrically read through 142, 144 and 146. During this time, the document table 32 is being transported in the sub-scanning direction (in the direction of the arrow) under the action of the drive motor 52, so the reflective document S2 is two-dimensionally scanned by the reflected illumination light L2, and its image information is will be taken out.

In this case, according to the present embodiment, the first reading means 112 for reading the transmissive original S1 and the second reader 114 for reading the reflective original S2 are incorporated into a single CCD camera 108, and The CCD camera 108 is configured to be able to move forward and backward along the optical axis of the transmitted illumination light L1 and the reflected illumination light L2 under the action of a moving means 150. Then, when placing the reflective original S2 on the base glass 56 and pressing it with the holding glass 57 to energize the reflective illumination means 170, as shown in FIGS. 4 and 5, the CCD camera 10
8 in the opposite direction to the arrow A (see the two-dot chain line in the figure), the second reading means 1 in this CCD camera 108
14 photoelectrically reads the image information carried on the reflective original S2.

On the other hand, when the transmission type document S1 is placed on the holding glass 57 and pressed by the holding glass 62 to energize the transmission illumination means 83, the CCD camera 10B is moved under the action of the moving means 150.
is moved by a distance l in the direction of the arrow. That is, the fifth
As can be understood from the figure, since the transmissive original S1 is placed above the reflective original S2, the transmissive original S1
The optical path length from to the CCD camera 108 is reflective type original S2.
is shorter than the optical path length of Therefore, by displacing the CCD camera 108 by a distance β in the direction of arrow A in accordance with the amount of reduction in the optical path length of the transmissive original S1, the optical path length of the transmissive original S1 becomes the same as the optical path length of the reflective original S2. Adjust accordingly.

As a result, for example, there is no inconvenience that the transmitted illumination light L1 does not form an image on the CCD 138 that constitutes the first reader 112, and image information carried on the transmissive original S1 and the reflective original S2 can be reliably and highly enhanced. The effect of being able to read accurately can be obtained.

Furthermore, the single CCD camera 108 performs the reading operation for the transmissive original SI and the reflective original S2, which have different reading positions. Therefore, the transmission type original St
Compared to a system in which the original document S2 and the reflective original S2 are read by separate CCD cameras, the apparatus 30 has the advantage that the entire apparatus 30 can be made smaller and lower in cost.

[Effects of the Invention] As described above, according to the present invention, when a reflective original is held down by a light-transmitting plate having an uneven surface and image information carried on the reflective original is read, a CCD camera is used. It is moved along the optical axis toward the reflective type document side. On the other hand, when a transmissive original is placed on the light-transmissive plate and image information carried on the transmissive original is read, the CCD camera is moved in a direction away from the transmissive original along the optical axis. let

Therefore, it is possible to adjust the optical path lengths from the transmissive original and the reflective original, which have different reading positions, to the CCD camera to be the same, and the image information carried on the transmissive original and the reflective original can be read with high precision. This has the effect of making it possible to read the image.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments.
Of course, various improvements and changes in design are possible without departing from the gist of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of the structure of an image reading device according to the present invention, FIG. 2 is a perspective explanatory view showing a separated state of a document table that constitutes the image reading device, and FIG. 3 is a configuration of the image reading device. FIG. 4 is a perspective explanatory diagram showing the internal structure of the CCD camera, FIG. 5 is an explanatory diagram of the operation of the CCD camera shown in FIG. 4, and FIGS. 6 and 7 are transmission type. FIG. 3 is a partial cross-sectional view illustrating a state in which an original and a reflective original are read. 30... Image reading device 32... Original table 36
... Image reading section 57 ... Presser glass 58
...first presser cover 62...presser glass 64
...Second presser cover 108...CCD camera 112.1
14...Reading means 116...Imaging lens 118
... Optical path switching means 120 ... Reflector 138.
142.144.146...CCD150...Movement means 162...Drive morph S2...Reflection type original 160...Ball screw Sl...Transmission type original

Claims (1)

[Claims] (1) An image reading device that is capable of photoelectrically reading image information carried on a transmissive original and a reflective original at different reading positions, and that combines image information along the main scanning line of the transmissive original. a first reading means for reading through the imaging optical system; and a second reading means for reading image information along the main scanning line of the reflective original through the imaging optical system;
A moving means is provided for integrally moving the first reading means, the second reading means, and the imaging optical system forward and backward along the optical axis in accordance with the reading positions of the transmission type original and the reflection type original. An image reading device characterized by: (2) The apparatus according to claim 1, wherein a document table is provided which is movable in a sub-scanning direction substantially perpendicular to a main scanning direction in which reflected illumination light and transmitted illumination light are irradiated, and the document table is used when reading a reflective type document. . An image reading device comprising: a light-transmissive plate placed on and pressing the reflective original, and on which the transmissive original is placed when reading the transmissive original.