JPH02217067A - Image reader - Google Patents

Abstract

PURPOSE:To suppress the damages of an original and a light transmissive plate body and to attain highly accurate image reading work by providing an image reader with a detecting means for detecting whether the light transmissive plate body is accurately arranged on an original platen or not. CONSTITUTION:When detecting light L0 is projected from a projector 80 by driving a photoelectric switch 78 constituting the detecting means 70, the detecting light L0 reaches a mask member 40 through an aperture part 84 and a light reflector 72 of the 2nd pressing cover 42 is irradiated with the light L0 through an aperture part 60 formed on the mask member 40. Thereby, the detecting light L0 reflected by the reflector 72 is made incident from the aperture parts 60, 84 upon a photodetector 82, so that the accurate arrangement of the 2nd pressing cover on the required position can be detected. Consequently, the original platen 12 can be prevented from being sub-scanned and carried in the inclined state of the plate body 52 from the original platen 12 or no arrangement state of the plate body 52 and efficient image reading word can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image reading device, and more particularly, a document placed on a document table is held by a transparent plate, and the transparent plate is Automatically detects whether or not the document is placed securely on the document, thereby preventing the document or the transparent plate from contacting other members and being damaged when the document table is conveyed in the sub-scanning direction. Moreover, the present invention relates to an image reading device that can read image information carried on the document with high precision.

[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 a transmitted light type that reads image information carried on a transparent film, etc., and a reflected light type that reads image information on non-transparent printed materials, etc., depending on the use and purpose. There is a type. Here, when transporting a transmissive original such as a film or a reflective original such as a printed matter in the sub-scanning direction, the original is actually placed on a document table that is movable in the sub-scanning direction, and The document is positioned and held on the document table by a transparent plate.

However, especially when attempting to read a document to be read by replacing it with another document relatively frequently, there is a high risk that the transparent plate will not be reliably placed on the new document. For this reason, for example, if the document table is conveyed in the sub-scanning direction while the transparent plate is placed on the document at an angle,
This poses an inconvenience in that the transparent plate comes into contact with other members and is damaged.

Furthermore, there are cases where the document table is conveyed in the sub-scanning direction without placing the transparent plate over the document. As a result, it has been pointed out that the original document may come into contact with other members and be damaged, or may be misaligned on the document table, making it impossible to achieve accurate image information reading.

[Object of the Invention] The present invention has been made in order to overcome the above-mentioned disadvantages, and includes providing a light reflector on a light-transmitting plate for holding a document on a document table. A detecting means is provided that detects positional information of the transparent plate by irradiating detection light onto the light reflector and receiving the reflected light at the position, and thereby detects the position of the transparent plate before reading the image. The presence or absence of a body and its position can be detected automatically and reliably.
It is an object of the present invention to provide an image reading device that prevents damage to a document and a transparent plate and that can perform highly accurate image reading work.

[Means for Achieving the Object] In order to achieve the above-mentioned object, the present invention provides a method for moving the document table in the main scanning direction while irradiating illumination light onto the document placed on the document table in the main scanning direction. An image reading device that photoelectrically reads image information carried on a document while being conveyed in a substantially orthogonal sub-scanning direction, the device having a light-transmitting plate for holding down the document placed on a document table. In addition, the present invention is characterized by comprising a detection means for detecting whether or not the light-transmitting plate is accurately placed with respect to the document table.

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

In FIG. 1, reference numeral 10 indicates an image reading device according to this embodiment. This image reading device 10 includes a document table 12 on which a document is set, a conveyance mechanism section 14 that conveys the document table 12 in the six directions of arrows, and a document conveyed in the sub-scanning direction by the conveyance mechanism section 14 to scan the document table. It basically consists of an image reading section 16. In this case, the transport mechanism section 1
4 is disposed on the first housing 18, and the image reading section 1
6 is provided inside the second casing 20 placed on the first casing 18 . Note that an opening 22 is formed on one side of the second housing 20 to allow the document table 12 to pass through, and also allows dust, external light, etc. to enter the second housing 20 from the outside. The dimensions of this opening 22 are selected to match the dimensions of the document table 12 as much as possible in order to prevent this from occurring.

First, the transport mechanism section 14 will be explained. Horizontal and parallel guide bars 24a and 24b are disposed on the upper surface of the first housing 18, and these guide bars 24
Both ends of a and 24b are supported by support stands 26 and 28 on the first housing 18. Further, the guide bar 24
A ball screw 30 is disposed on the supports 26 and 28 in parallel with a and 24b, and this ball screw 30 is rotationally driven by a drive motor 32 provided within the first housing 18.

The guide bars 24a and 24b are provided with an original table 1 holding a transmissive original S1 or a reflective original S2 carrying image information.
2 is movably supported.

That is, as shown in FIGS. 2 and 3, the document table 12 includes a base 34 and a table glass 3 on which the reflective document S2 is placed.
6, a first presser cover 38, a mask member 40 used when the transmission type document S1 is placed on the first presser cover 38, and a second presser cover 42.

A hollow portion 43 into which a prismatic body to be described later is inserted into the base 34
an opening 44 for guiding transmitted illumination light, which will be described later, to the transmission type document S1 via the base glass 36.
is defined. Furthermore, support members 46a and 46b are attached to the side surface of the base 34 to support the first presser cover 38 so as to be openable and closable in the directions of arrows B3 and B2, and on the upper surface of the end opposite thereto, support members 46a and 46b are attached in the vertically upward direction. pin members 48a, 48b oriented toward
is planted. On the other hand, the first presser lid 38 has a frame 50 having a substantially U-shaped cross section and a first light-transmitting plate, for example, a presser glass 52, which is held between the frame 50.
Holes 54 for inserting pin members 48a and 48b into
a, 54b are drilled, and the pin member 48a,
The length of 48b is selected to be larger than the thickness of the frame 50. Furthermore, an uneven surface 56 is formed on the inner surface of the presser glass 52, that is, on the one surface facing the reflective original S2. In this case, the uneven surface 56 may be formed by etching, or ground glass may be used as the holding glass 52.

Further, the mask member 40 has a substantially thin plate shape, and a rectangular opening 58 is formed in the center thereof corresponding to the transmission type original S1, which is smaller in size than the reflection type original S2. An opening 60 is provided near the opening 58 to allow detection light from a detection means, which will be described later, to pass therethrough. Note that holes 62a and 62b are provided at one end of the mask member 40 in the transverse direction, into which pin members 48a and 48b are fitted to perform positioning and fixing functions of the mask member 40.

Next, the second retainer lid 42 has a second light-transmissive plate, for example, a retainer glass 64, and an antireflection coating layer 64a is formed on at least one side of the retainer glass 64. Hook bodies 66a166b made of a resin material are fixed to both longitudinal ends of the presser glass 64, and handles 68a, 68b are provided on each hook body 66a166b. Therefore, a light reflector 72 constituting the detection means 70 is attached to the hook body 66b in a position corresponding to the opening 6° provided in the mask member 40. The light reflector 72 is substantially made of a mirror-finished metal plate, but may also be made of, for example, a flat resin plate or glass plate. In addition, the light reflector 7
2 can also be directly attached to the holding glass 64.

On the other hand, a detection means 7 is installed in a hollow prismatic body 76 whose both ends are supported on the first housing 18 by support stands 74a, 74b.
A photoelectric switch 78 constituting 0 is provided. That is, in the original position of the document table 12 shown by the two-dot chain line in FIG.
A photoelectric switch 78 is provided within 6. The photoelectric switch 78 is substantially integrally composed of a light projector 80 and a light receiver 82, and detection light is led out from the light projector 80 and reflected by the reflector 72. An opening 84 is formed in the prismatic body 76 for the passage of (see FIGS. 1 and 4). In this case, the detection light derived from the light projector 80.

When the light is not incident on the light receiver 82, the driving of the transport mechanism section 14 is stopped, and a warning means such as a warning light emitting section or a warning buzzer is energized outside the image reading device 10. Here, the original position of the document table 12 refers to a reference position provided outside the second casing 20 for attaching, detaching, and positioning the reflective document S2 and the transmissive document S1.

Furthermore, a transmitted illumination means 93 is housed in the prismatic body 76, and this transmitted illumination means 93 is composed of a halogen lamp, a xenon lamp, etc., and has a light source 98 that outputs transmitted illumination light L1 and a light guiding property at both ends. and an optical fiber bundle 102 formed by bundling a large number of optical fibers 100 held by members 99a and 99b. Further, a cylindrical rod lens 104 is disposed within the prismatic body 76 to condense the transmitted illumination light L1 guided by the optical fiber bundle 102 into a line.

Transmitted illumination light L focused by the rod lens 104
1 is guided to the transmission type original S through the hairline mirror 106 through an opening 107 formed in the prismatic body 76. In this case, the hairline mirror 106 illuminates the transmissive original S1.

is set to be incident obliquely at a predetermined angle. In fact, the hairline mirror 106 is arranged so that the angle between the transmitted illumination light and the normal to the base glass 36, that is, the virtual perpendicular P, is approximately 30 degrees.

On the other hand, inside the second housing 20 is a mirror 10B that horizontally reflects the transmitted illumination light that has passed through the transmission type original S in the diagonal direction, and a mirror 10B that receives the transmitted illumination light L1 that has been reflected in the horizontal direction by the mirror 108. A CCD camera 110 is provided as an image reading means for converting the image into an electrical signal.

Further, within the second housing 20, a reflective illumination means 130 is provided that irradiates the reflective original S2 with reflected illumination light, which will be described later.

In this case, the reflected illumination means 130 includes a light source 132 that outputs reflected illumination light L2, and a holding member 134a whose both ends are light guiding.
, 134b.
The optical fiber bundle 138 includes a curved optical fiber bundle 138 formed by bundling the optical fiber bundles 138 and cylindrical rod lenses 140 that condense the reflected illumination light L2 guided by the optical fiber bundles 138 into a line shape. At this time, the position of the holding member 134b is selected so that the illumination angle α between the reflected illumination light L2 emitted from the holding member 134h and the virtual perpendicular P perpendicular to the document table 12 is about 15°. The reflected illumination light L2 collected by the rod lens 140 reflects the reflective original S2 and then passes through the mirror 108 to the C.
The light enters the CD camera 110. At this time, CCD camera 1
10 is disposed at a position where reflected illumination light L2 reflected at a reading angle β of about 30° with respect to the virtual perpendicular P can be read via a mirror 108.

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, first move the document table 12 to its original position (see the two-dot chain line in FIG. 1), and then move the first presser cover 38 of the document table 12 in the direction of arrow B2. The pin members 48a, 4 are inserted into the holes 54a154b of the frame body 50.
8b is fitted to fix the frame 50 to the base 34. Next, the mask member 40 is placed on the presser glass 52 through the pin members 48a, 48b and the holes 62a, 62b, and the transmission original S1 is placed in the opening 58 formed in the mask member 40. At this time, the transmission original S1 is attached to a mount 150, and the holes 152a and 152b formed in the mount 150 are inserted into the pin member 48a1.
48b to position the transmission type original S1 with respect to the base 34. Further, a positioning mark (not shown) is provided on the mount 150 or the mask member 40, and the second presser cover 42 is placed on the mask member 40 via the mark, and the presser glass of the second presser cover 42 is placed on the mask member 40 using the mark. 64 and the presser glass 52 of the first presser lid 38 to sandwich the transmission type original Sl (see FIG. 4).

Here, the photoelectric switch 78 constituting the detection means 70 is driven to emit detection light from the light projector 80. Deriving this detection light. The light passes through the opening 84 and reaches the mask member 40, and is irradiated onto the light reflector 72 of the second presser lid 42 through the opening 60 formed in the mask member 40. Therefore, the detection light is reflected by the light reflector 72. enters the light receiver 82 through the aperture 60.84, thereby causing the second
It is detected that the presser lid 42 has been accurately placed at the desired position.

Next, the document table 12 is conveyed in the six directions of the arrows under the action of the drive motor 32 and moved to a predetermined portion of the image reading section 16 . When the original platen 12 holding the transparent original S1 reaches a predetermined portion of the image reading section 16, the reading operation of the image information carried by the transparent original S1 is started. That is,
The transmitted illumination light L1 output from the light source 98 passes through the optical fiber bundle 102, is condensed by the rod lens 104, is reflected by the hairline mirror 106 at a predetermined angle with respect to the vertical upward direction, and is reflected from the opening 107 into the document. You will be led to platform 12.

Then, the transmitted illumination light irradiates the transmission type original Sl through the base glass 36 and the presser glass 52 in the direction of arrow C shown in FIG. 3, that is, in the main scanning direction. in this case,
The transmitted illumination light passes through the transmission type document S1 and extracts image information as an optical signal. The image information as an optical signal passes through the presser glass 64, is reflected in the horizontal direction by the mirror 108, enters the CCD camera 110, and is converted into an electrical signal within the CCD camera 110.

During this time, the document table 12 is being transported in the sub-scanning direction (in the direction of the six arrows) under the action of the drive motor 32. Therefore, the transmission type original S1 is illuminated two-dimensionally by the transmission illumination light, and its image information is extracted. After the reading operation is completed, the drive motor 32 is rotated in the opposite direction to move the document table 12 to its original position.

On the other hand, when reading the reflective original S2, first,
The second presser lid 42 is attached to the base 34 via the handles 68a and 68b.
Then, the transmission original S1 and the mask member 40 are removed from the presser glass 52.

Next, the first presser lid 38 is lifted in the direction of arrow B1.

In this state, after placing the reflective original S2 facing upward on the table glass 36, the first presser cover 38 is displaced in the direction of arrow B2, and the pin members 48a and 48a are inserted into the holes 54a and 54b of the first presser cover 38. 48b is inserted. Then, the document table 12 is conveyed in the direction of arrow A under the action of the drive motor 32 and moved to a predetermined portion of the image reading section 16 .

When the document table 12 reaches a predetermined part of the image reading section 16,
The reading operation of the reflective original S2 is started.

That is, the reflected illumination light L2 output from the light source 132 passes through the optical fiber bundle 138, is focused by the rod lens 140, and is guided to the document table 12. Then, the reflected illumination light L2 irradiates the reflective original S2 in the main scanning direction through the presser glass 52, and image information is extracted as an optical signal.

This image information as an optical signal is reflected diagonally off the presser glass 52 and then transmitted to the CCD camera 1 via the mirror 108.
10 and converted into an electrical signal. During this time, the document table 1
2 is conveyed in the sub-scanning direction under the action of the drive motor 32, the reflective type original S2 is two-dimensionally scanned by the reflected illumination light L2, and its image information is extracted.

In this case, according to the present embodiment, when reading the transmissive original S1, the transmissive original SI is placed on the original platen 12 arranged at the original position, and a second After the presser lid 42 is mounted, the detection means 70 is driven. Therefore, as shown in FIG. 4, detection light is emitted from the light projector 80. If the light is reflected by the light reflector 72 and enters the light receiver 82, it is detected that the second presser cover 42 is accurately disposed at the desired position with respect to the document table 12.

As a result, if the transmissive illumination means 93 is energized while sub-scanning and conveying the document table 12 in the direction of the arrow A, the transmissive document S,
The image reading operation can be performed satisfactorily.

On the other hand, the second presser cover 42 may be placed on the document table 12, for example, in a tilted state with respect to the sub-scanning direction, as shown by the two-dot chain line in FIG. Here, when the detection means 70 is driven, detection light is emitted from the light projector 80. After being reflected by the light reflector 72, the light does not enter the light receiver 82. Therefore, it is automatically detected that the second presser cover 42 is not placed accurately, and, for example, the warning light emitting unit or the warning buzzer is activated to notify the operator, and the transport mechanism unit 14 is not driven. . Therefore, the document table 12 is not transported in the six directions of the arrows while the second presser cover 42 is tilted with respect to the sub-scanning direction or the main scanning direction, and the document table 12 is formed to correspond to the size of the document table 12. This makes it possible to prevent the second presser cover 42 from falling from the document table 12 and being damaged due to the second presser cover 42 not being able to enter the opening 22 in which the document is placed.

Furthermore, if the second presser cover 42 is not placed on the document table 12, the detection light will be emitted to the light receiver 82 when the detection means 70 is driven. is not incident, and the warning light emitting section is energized.

As a result, the document table 12 can be opened without the second presser cover 42.
There is no risk that the transmissive original S1 will come into contact with other members or fall without passing through the opening 22 due to bending of the transmissive original S1 itself.

As a result, an effect can be obtained in that the image reading operation of the transparent original S can be accomplished efficiently and with high precision.

[Effects of the Invention] As described above, according to the present invention, the original placed on the original table is held down by the light-transmitting plate, and the light-transmitting plate is securely placed in a predetermined position. It is possible to automatically detect whether it is placed or not. Therefore, it is possible to prevent the document table from being conveyed in the sub-scanning direction when the light-transmitting plate is arranged at an angle with respect to the document table, or when the light-transmitting plate is not arranged. It becomes possible. Therefore, it is possible to prevent the light-transmitting plate and the original from falling or being damaged, and it is possible to carry out an efficient image reading operation.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments.
It goes without saying that various improvements and changes in design are possible without departing from the gist of the present invention, for example, various mechanisms may be employed in place of the photoelectric switch as the detection means.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an image reading device according to the present invention, FIG. 2 and FIG. 3 are perspective illustrations of the document table in FIG. 1, and FIG. 4 is a configuration of an image reading device according to the present invention. FIG. 3 is an explanatory diagram of the operation of the detection means. 10... Image reading device 12... Transport platform 14
... Conveyance mechanism section 38 ... Presser lid 40 ...
・Mask member 42...presser lid 52.64・
... Holder glass 70 ... Detection means 72 ... Light reflector 78 ... Photoelectric switch 80 ...
Emitter 82...Receiver 93...Transmitted illumination means 130...Reflected illumination means Ll...
Transmitted illumination light Sl...Transmission type original L2...Reflected illumination light S2...Reflection type original

Claims (1)

[Claims] (1) While illuminating the original placed on the original platen in the main scanning direction, the original platen is conveyed in the sub-scanning direction substantially perpendicular to the main scanning direction, and the image information carried on the original document is read. An image reading device that reads photoelectrically, including a light-transmitting plate for holding the original placed on a document table, and whether the light-transmitting plate is accurately positioned with respect to the document table. An image reading device characterized by comprising a detection means for detecting whether or not the image is detected.