JPH0267557A - Picture reader - Google Patents

Abstract

PURPOSE:To read the picture of an original with a suitable density by providing a density reference plate which s used for reading the information related to the original reading condition while the reference plate is pressed by a transparent press plate to a state where the surface of the reference plate substantially made coincident with that of the original. CONSTITUTION:A digitizer 52 sets the reading extent of the picture information carried on a light reflecting type original S in a state where the original S is placed on the digitizer 52. The transparent press plate 54 holds the original S together with the digitizer 52 between them. Carrying means 24a and 24b and 34 carry the digitizer 52 and press plate 54 to prescribed positions while the digitizer 52 and press plate 54 hold the original S and a picture reading means 14 obtains the picture information of the held original S from the reflected light of the original S irradiated with the light of the means 14 through the press plate 54. A density reference plate 80 obtains the reading condition information of the original S while it is pressed by the press plate 52 to a state where surface of the plate 80 substantially made coincident with that of the original S. Therefore, the picture of the original can be red with a suitable density.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image reading device, and more particularly, when reading image information by irradiating a document carrying image information with light, the present invention relates to an image reading device.
Offset information of the optical system or electrical system obtained by providing a density reference means at a predetermined position under the same conditions as the original, and irradiating the density reference means with light in advance;
The present invention relates to an image reading apparatus configured to adjust these optical systems and electrical systems based on image reading condition information such as gain information and read an image represented on a document at a suitable density.

[Background of the Invention] For example, in the fields of printing and plate making, image scanning reading records are used to electrically process image information carried on a manuscript to create a film master plate for the purpose of streamlining work processes, improving image quality, etc. The system is widely used.

This image scanning reading/recording system basically consists of an image reading device and an image recording device. That is, in the image reading device, image information of a document being conveyed in the sub-scanning direction is read in an image reading section via a light beam, and converted into an electrical signal by a photoelectric conversion element. Next, the image information photoelectrically converted by the image reading device is subjected to arithmetic processing such as gradation correction and edge enhancement according to the plate-making conditions by the image recording device, and then converted to an optical signal consisting of laser light, which is then used to film the film. Recording and reproduction are performed on a record carrier made of a photosensitive material such as. In addition,
This record carrier is developed by a predetermined developing device,
It will be used for printing, etc. as a film original plate.

Incidentally, an image reading device may require a function of photoelectrically converting only a predetermined range of image information out of the image information carried on a document and providing it to an image recording device. Therefore, for example, after specifying the reading range of image information using a mouse or the like with the original placed on the digitizer, the original is transported to the image reading unit by the transport means, and based on the reading range data by the digitizer, There are devices that are configured to read predetermined image information.

However, in such devices, the document may meander while being conveyed to the image reading section by the conveyance means, or the conveyance speed may change, making it difficult to accurately read image information within a specified range. Disappearances often occur. In addition, if the document placed on the digitizer is a sheet of film or paper that is easily deformed, the deformation not only reduces the positioning accuracy in the image reading unit, but also may cause damage during transportation. However, there is a possibility that a situation may occur in which the reading operation becomes impossible.

In view of this kind of inconvenience, the present applicant has developed a structure in which the original carrying image information can be conveyed to the image reading unit while being held between a digitizer for specifying a reading range and a transparent pressure plate. He has devised an image reading device that can smoothly transport images to an image reading unit and that can accurately read image information in a specified reading range, and has already filed a patent application No. 62 on February 2, 1988. A patent application was filed as No.-22892.

[Object of the Invention] The present invention has been made in connection with the above-mentioned image reading device, and when reading image information carried on a document via an optical scanning system, the optical scanning system and/or the electrical system are In order to obtain image reading condition information such as offset information and gain information, a density reference means is provided at a position under the same conditions as the original to be read, and the image density can be adjusted based on the information obtained from this density reference means. An object of the present invention is to provide an image reading device configured as described above.

[Means for Achieving the Object] In order to achieve the above-mentioned object, the present invention provides a digitizer that sets a reading range of image information carried on a light-reflecting original in a state where the original is placed thereon, and a digitizer that sets a reading range of image information carried on the original. a transparent pressure plate that cooperates with the original to clamp the original, a conveyance means that transports the digitizer and the transparent pressure plate to a predetermined position while holding the original; an image reading means for irradiating light and obtaining reflected light from the document to obtain image information; and a means for obtaining reading condition information of the document by being pressed against a transparent pressure plate so as to be substantially flush with the document. It is characterized by comprising a concentration reference plate.

[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, and this image reading device 10 is connected to a document manual section 1.
2, an image reading section 14, and an image scanning section 16. In this case, the document input section 12 and the image reading section 14 are arranged on the first casing 18, and the image scanning section 16 is arranged on the second casing 20 that defines the upper space of the image reading section 14. Located inside. Note that the document manual section 12 and the image reading section 14 communicate with each other through a passage 22 defined in the second casing 20 .

Horizontal and parallel guide bars 24a and 24b are provided between the document manual section 12 and the image reading section 14, and both ends of these guide bars 241 and 24b are provided on the first housing 18. Support stands 26a126b and 28
a, 28b. In addition, the guide bar 2
A ball screw 34 whose both ends are supported by bearings 30 and 32 is arranged in parallel between 4a and 24b. In this case, the ball screw 34 is rotationally driven by a drive motor 36 provided within the first housing 18. That is, a pulley 38 is engaged with the end of the ball screw 34 on the image reading unit 14 side, and a pulley 42 is also engaged with the rotating shaft 40 of the drive motor 36.
A belt 44 is suspended between.

On the other hand, a document table 46 holding a document S carrying image information is movably supported by the guide bar 243.24b. That is, as shown in FIGS. 2 and 3, the document table 46 includes a base 48, a digitizer 52 supported on the base 48 via elastic support mechanisms 50a to 50d, and the digitizer 52. It includes a platen glass 54 made of a transparent pressure plate that presses the original S under cooperative action.

A female screw member 56 is disposed in the center of the base 48, and the ball screw 34 is screwed into the female screw member 56. Also,
Guide holes 58a158 are provided on both sides of the female screw member 56.
guide holes 58a, 58b, and guide bars 24a, 24b are inserted through these guide holes 58a, 58b.

As shown in FIG. 4, the elastic support mechanisms 50a to 50d disposed on the lower surface of the base 48 are connected to a second cylindrical portion 64 supported within a first cylindrical portion 60 via a support plate 62. A shaft 68 having a plate 66 projecting upward from the first cylindrical portion 60 is inserted into the second cylindrical portion 64 . A screw 70 is fixed to the lower end of the shaft 68, and the lower end of the screw 70 has stoppers 72a, 7
2b are screwed together. A spring 74 is interposed between the lower surface of the plate 66 and the upper surface of the second cylindrical portion 64, and the shaft 68 is urged upward by the elastic force of the spring 74. Here, the shaft 68
The plate 66 provided at the upper end supports the digitizer 52 surrounded by the frame 76 from below. In addition, the stopper z) 72a.

72b is the digitizer 5 due to the elastic force of the spring 740.
2 plays a role in preventing it from rising more than necessary.

In fact, as shown in FIGS. 2 and 3, the digitizer 5
On the upper surface of 2 is a first spongy body 7 having a predetermined thickness and having high elasticity.
7 is attached, and the original S is placed on this first corpus cavernosum 77. On the other hand, a second corpus cavernosum 78 made of the same material as the corpus cavernosum 77 and having a thickness equal to or equal to that of the corpora cavernosa is attached to the tip corner of the frame 76, and the upper surface of the second corpus cavernosum 78 is A concentration reference plate 80 is provided. It is preferable that the density reference plate 80 has a white surface and a thickness substantially the same as that of the document S. However, since the density reference plate 80 only needs to be pressure-bonded to the platen glass 54, it is not necessary that its thickness be the same as that of the original S. Therefore, as will be described later, since the original S and the density reference plate 80 are flush with each other,
It is possible to irradiate the density reference plate 80 with the light beam under the same conditions as for the original S.

The base 48 is surrounded at its peripheral side by a frame plate 82 having a substantially U-shaped cross section. In this case, hinge members 84a and 84b are attached to the sides of the frame plate 82. Hinge members 84a, 8
4b is a main body portion 86 attached to a frame plate 82 and an adjustment screw 8.
8, the support part 90 is movable in the direction of the arrow shown in FIG. Here, a frame body 94 having an oval-shaped cross section is fixed to the hinge 92, and a frame body 96 having a U-shaped cross section is further fixed to the inner peripheral portion of this frame body 94. A flat platen glass 54 is held between these frames 94 and 96. Note that an elastic body 9 for absorbing impact is provided on the upper surface of the frame plate 82 facing the frame body 96.
7a to 97c are attached.

Inside the outer part of the frame 94, at the center of the side opposite to the hinge 92, there is provided a handle part 100 having an oval-shaped cross section and a lock hole 98 formed in the center part, and a lock hole 98 is provided below the handle part 100. Member 102 is attached. This lock member 10
2 has a main body part 104 and an adjustment screw 106 to adjust the main body part 10.
Support part 10 that can be displaced in the direction of the arrow shown in FIG.
8, and an abbreviated lever 112 which has an operating portion 110a and a claw portion 110b and is pivoted to the support portion 108. In this case, the locking member 102 is
The second claw portion 110b engages with the lock hole 98 of the handle portion 100, thereby locking the platen glass 54 to the base 48 side.

On the other hand, an image scanning section 16 is provided above the image reading section 14 . This image scanning section 16 includes a light source 1 that outputs light L1.
14, an optical fiber bundle 118 that guides the light L1 to a cylindrical lens 116, a mirror 120 that receives the reflected light L2 from the document S, and a CCD (charge coupled device) that photoelectrically converts the reflected light L2 to obtain an image signal. ) camera 122.

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

First, the lock is released by pressing the operating portion 110a of the lever 112 constituting the locking member 102 on the document table 46 with a finger or the like, and the platen glass 54 is lifted up via the handle portion 100 (see FIG. 2). Next, in this state, the image information of the document S is transferred to the platen glass 54.
After placing the document S on the digitizer 52 with the document facing upward, the platen glass 54 is pressed against the document S. In this case, the claw portion 110b of the lever 112
It engages with the lock hole 98 of No. 0 and enters the locked state. Therefore,
A desired reading range is specified from the top surface of the platen glass 54 using a mouse or the like in the image information carried on the document S.

Here, the digitizer 52 is pressed toward the platen glass 54 by four elastic support mechanisms 50a to 50d arranged on the base 48. That is, the shaft 68 constituting the elastic support mechanisms 50a to 50d presses the plate 66 disposed at the upper end thereof upward by the elastic force of the spring 74. As a result, the digitizer 52 is moved to the platen glass 54 by the plate 66.
It is pushed up towards. Moreover, in the present invention, the first corpus cavernosum 77 having high elasticity is provided on the upper surface of the digitizer 52.
has been set up. Therefore, the original S is pressed by the elastic force of the first corpus cavernosum 77 and becomes flat along the platen glass 54, so that its flatness is optimally maintained. Therefore, the reading range of the document S can be set extremely accurately using a mouse or the like. Note that if a thin platen glass 54 is used, the digitizer 52
The accuracy of the reading range can be further improved.

Next, the document table 46 is conveyed to the image reading section 14 under the driving action of the drive motor 36 . That is, as the rotation shaft 40 of the drive motor 36 rotates, the belt 44
The ball screw 34 rotates through the ball screw 34.
The image reading unit 14 is in a state where the document table 46 is supported by the guide bar 243.24b via the female screw member 56 that is screwed into the
transported to the side.

Next, read information related to the document S is obtained from the density reference plate 80. That is, the light L1 output from the light source 114 reaches the cylindrical lens 116 via the optical fiber bundle 118, and is focused on the lower surface of the platen glass 54 under the condensing action of the cylindrical lens 116.

The light transmitted through the platen glass 54 reaches the density reference plate 80, and the white density reference plate 80, which has a density within the range of 0.03≦D≦0.04, directs the reflected light L2 to the mirror 1.
Send to 20. Light L reflected by this mirror 120
2 reaches a CCD camera 122, and image information is obtained.

In this case, as described above, since the density reference plate 80 is in contact with the platen glass 54 with the same pressing force as the original S,
Under the same conditions, in other words, reading condition information including the optical path length of the same optical system as the document S and the deviation of the illumination position is obtained.

This reading condition information is introduced into the optical control system and the electrical control system to set the reading conditions for the document S.

Next, when the document table 46 is sent to a predetermined portion of the image reading section 140, the image scanning section 16 starts reading the image information carried on the document S. That is, as above,
The light L+ output from the light source 114 reaches the cylindrical lens 116 via the optical fiber bundle 118,
The original S, which is focused by the cylindrical lens 116 and conveyed in the sub-scanning direction by the drive motor 36, is irradiated through the platen glass 54 in a direction perpendicular to FIG.

Here, the document table 46 holds the document S between the digitizer 52 and the platen glass 54, and the guide bar 24a
, 24b in the sub-scanning direction.

Therefore, the document S does not meander or deform during transportation, and extremely accurate transportation is performed. Therefore, from the image reading unit 14, the document S
The light irradiated on the image is accurately guided to the image reading range specified in the document input section 12. As a result, it becomes possible to perform extremely accurate image reading operations.

Note that the image information carried on the original S reaches the mirror 120 as reflected light L2, and is reflected by this mirror 120 and transmitted to C.
It is guided by a CD camera 122. The CCD camera 122 photoelectrically converts the reflected light to form a predetermined image signal.

[Effects of the Invention] As described above, according to the present invention, a light-reflecting original carrying image information is conveyed while being held between a digitizer and a transparent pressure plate, a light beam is irradiated onto the original, and an image is generated using the reflected light. When attempting to read information, a density reference means is provided which is set under substantially the same conditions as the original, that is, flush. By irradiating the original with light in advance, this density reference means receives offset information or gain adjustment information when amplifying the output of the CCD, which performs photoelectric conversion based on the reflected light, with an amplifier. It has gained. Therefore, based on this information, it is possible to obtain image information of the document in a desired state in order to control the optical system or the electrical system. Moreover, according to the present invention, since the density reference means is set under substantially the same conditions as the original, the optical path length of the optical system is the same as that for the original, and therefore the deviation of the illumination position with respect to the original is prevented. It doesn't cause it.

Furthermore, since the density reference means uses a corpus cavernosum to adjust the height to be the same as the original, it has the advantage of being extremely simple in structure and convenient to handle.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments.
For example, it is possible to separate the second corpus cavernosum from the digitizer without placing the first corpus cavernosum and the second corpus cavernosum having a concentration reference plate on the digitizer, etc. Of course, various improvements and changes in design are possible without departing from the above.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an image reading device according to the present invention, FIG. 2 is a perspective explanatory diagram of a document table in the image reading device according to the present invention, and FIG. 3 is a diagram showing a document table in the image reading device according to the present invention. FIG. 4 is a cross-sectional configuration diagram showing an elastic support mechanism in an image reading device according to the present invention, and FIG. 5 is a partial cross-sectional view of a portion related to a density reference plate in an image reading device according to the present invention. 10... Image reading device 12... Manuscript manual section 14... Image reading section 16... Image scanning section 18.20... Housing 24a, 24b... Guide bar 34... Ball screw 36... Drive motor 46... Document table 50a-50d... Elastic support mechanism 52... Digitizer 54... Platen glass 77.78.
...Cavernous body 80...Concentration standard plate 114.
...Light source 116...Cylindrical lens 118...Optical fiber bundle 122...CCD camera 120...Mirror, <Z, D 2bO

Claims (1)

[Claims] (1) a digitizer that sets a reading range of image information carried on the original with a light-reflective original placed thereon; and a transparent pressure plate that cooperates with the digitizer to hold the original;
a conveying means for conveying the digitizer and the transparent pressure plate to a predetermined position while holding the document; and a conveying means for conveying the digitizer and the transparent pressure plate to a predetermined position while holding the document; An image reading device comprising: an image reading means for obtaining information; and a density reference plate pressed against a transparent pressure plate so as to be substantially flush with the original to obtain information on reading conditions of the original.