JPH0478264A - Picture reader - Google Patents

Abstract

PURPOSE:To block dispersion due to Newton ring caused in a picture and to obtain a reproduced picture with high quality by exerting a mechanical pressure varied timewise to a plate being a component of a cassette. CONSTITUTION:When an original cassette 50 is carried in the direction of the arrow X by a subscanning device to start read of a picture S, a motor 82 of a cassette vibration device 80 is energized, an eccentric cam 84 is driven and a roller 86 is vibrated in the direction of the arrow Y. A cover glass plate 58 is vibrated by the vibration of the roller 86 and a gap between the glass plate 58 and the original S is changed synchronously with the vibration. Thus, production and relinquish of the Newton ring are repeated. Then a reproduced picture with excellent quality without dispersion in the Newton ring is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image reading device that irradiates a light beam onto a sheet-like original on which image information is recorded and reads the reflected light or transmitted light.

[Prior art] In the fields of printing, plate making, etc., for the purpose of streamlining work processes and improving image quality, film master plates are created by electrically processing the shading of image information carried on a manuscript. An image scanning reading and reproducing system is adopted.

In the image reading device that is the main body of the image scanning reading and reproducing system, a document positioned and stored in a document cassette, such as a developed film, is transported to a reading section, and the document cassette that supports the document is transported to the reading section. is conveyed in the sub-scanning direction.

In this case, the document cassette has a pair of support plates, at least one of which is made of a transparent material, and light reflected or transmitted from the document through the transparent support plates is transmitted to a CCD provided in a reading section. Image information is read by being photoelectrically converted by an optical/electrical conversion element such as.

By the way, in this type of document cassette, the document is directly positioned and placed on the support plate, so depending on the thickness, bending, etc. of the document, when the read image information is reproduced, the document may be There is an inconvenience that unevenness occurs in the reproduced image. That is, if the document and the support plate are not in close contact with each other and there is a gap between them that is on the order of the wavelength of the reading light to several tens of times the wavelength, unevenness due to Newton's rings will occur due to interference of the reading light.

Therefore, in order to eliminate the unevenness caused by Newton's rings, oil was conventionally injected between the original and the transparent support plate.
A method has been adopted in which the gaps existing between these are filled with oil.

However, this method of injecting oil between the original and the transparent support plate is cumbersome, and the work of removing oil from the original or cassette after use is also complicated, resulting in a time-consuming process. need a lot of.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned disadvantages, and it is possible to eliminate the Newton rings that occur in images without performing the necessary work to prevent the Newton rings from occurring. It is an object of the present invention to provide an image reading device which can prevent unevenness, thereby obtaining a high-quality reproduced image, and can significantly shorten working time.

[Means for Solving the Problems] In order to achieve the above object, an image reading device according to the present invention includes two plate-like bodies, at least one of which is transparent, disposed close to each other, A document cassette for placing a document between the plate-like bodies, illuminating the document with illumination light, and reading image information, etc. carried by the document; It is characterized by providing a vibration mechanism that applies temporally varying mechanical pressure to one of the plate-shaped bodies.

[Function] In the image reading apparatus according to the present invention, a mechanical pressure that changes over time is applied by a vibration mechanism to one of the plate-shaped bodies constituting the cassette that holds the original document between them during the image reading time. Therefore, the one plate-like body vibrates with respect to the other plate-like body.

Therefore, the Newton rings generated from the interference between the light related to the image information directly obtained from the document and the light related to the image information once reflected by the support plate of the document cassette change during the image reading time, and therefore It is possible to obtain a reproduced image without Newton's rings.

[Embodiment] Next, a preferred embodiment of an image reading device incorporating the vibration mechanism 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.

This image reading apparatus 10 has a cassette attachment/detachment section 12 at one end of the upper portion, and a document cassette 50, which will be described later, is introduced and taken out in this cassette attachment/detachment section 12. A cassette insertion opening 14 is provided adjacent to the cassette insertion/removal section 12, and a document cassette 50 is provided near the cassette insertion opening 14.
An identification mechanism 16 for identifying the type of document S held in the document cassette 50 is also provided. Identification mechanism 1
Reference numeral 6 includes a light emitting section 18 and a light receiving section 20, which are arranged to face each other with a document cassette 50 being conveyed therebetween.

One end of a transport mechanism 22 is disposed close to the identification mechanism 16, and the other end of the transport mechanism 22 extends above a rotary table, which will be described later.

The transport mechanism 22 has a transport roller 26 that comes into contact with the upper surface of the frame 52 of the document cassette 50, and the transport roller 26 transports the document cassette 50 in the direction of arrow X. Further, the transport mechanism 22 has a plurality of guide rollers 24 arranged along the transport direction, and below the transport mechanism 22, a document table 28 is moved in the sub-scanning direction (arrow X
(direction) so that it can move forward and backward. The sub-scanning mechanism 30 includes a rotational drive source 32, and a ball screw 34 connected to the rotational drive source 32 displaces the document table 28 in the direction of arrow X.

The document table 28 is provided with a trimming mechanism 36 that moves the document cassette 50 forward and backward in a direction perpendicular to the trimming direction, that is, the sub-scanning direction (direction of arrow X). The trimming mechanism 36 displaces the trim table 40 by a rotational drive source 38 attached to the document table 28. The trim table 40 has an opening 42 in which the document cassette 50 is positioned.
has. The document table 28 also includes a rotation mechanism 4 that rotates the document cassette 50 by a predetermined angle via a rotary table 46.
It has 4.

A cassette vibrating mechanism 80 is disposed on the other end side of the transport mechanism 22, and a light source 48 constituting a transmitted illumination mechanism is disposed near the cassette vibrating mechanism 80 in the main scanning direction substantially orthogonal to the direction of the arrow X. An image reading section 70 that photoelectrically reads the illumination light derived from the light source 48 is disposed below the light source 48 . The image reading section 70 includes an imaging lens 74 that can move forward and backward in the optical axis direction, and a photoelectric conversion section 76 that can move forward and backward with respect to the imaging lens 74 under the driving action of a rotational drive source 72. First, the photoelectric conversion unit 76 is composed of, for example, a CCD, and photoelectrically reads the image information recorded on the document S.

FIG. 2 shows a cassette that holds a document carrying image information.

The document cassette 50 includes a frame 52 formed in a substantially rectangular shape, a support glass plate 54 attached to a rectangular opening 53 formed in the center of the frame 52, and a cover glass plate 58. , the support glass plate 54 and the cover glass plate 58 are configured to sandwich the original document S to be read. In addition, in the figure, reference numerals 59a and 59b indicate support glass plates 54.
A hinge member for rotatably holding the cover glass plate 58 is shown.

By the way, the document cassette 50 is loaded into the image reading device 10 and transported in the direction of the arrow X, and the document cassette 50 and the document S held in the document cassette 50 are placed in the front part of the frame 52 in the X direction. A cassette identification section 56 for identification is provided. Note that the cassette identification section 56 is constituted by a light transmitting section having a predetermined pattern depending on the type of the document cassette 50 and the document S, for example. On the other hand, a cover glass plate 5 is provided at the rear of the frame 52 in the X direction.
A lever member 60 for locking 8 to the frame 52 is provided.

Therefore, details of the cassette vibration mechanism 80 according to the present invention are shown in FIG.

The cassette vibration mechanism 80 includes a motor 82 that is a rotational drive source, an eccentric cam 84 that is a transmission member for this rotation, a roller 86 that comes into sliding contact with the cover glass plate 58, and the eccentric cam 84.
and a rod 88 that locks the roller 86.

The image reading apparatus 10, the cassette vibrating mechanism 80, and the document cassette 50 used therein according to this embodiment are basically constructed as described above, and the operation thereof will be described next.

First, with respect to the document cassette 50 in the state shown in FIG.
The document S is fixed on the support glass plate 54, the cover glass plate 58 is pressed against the document S, and the cover glass plate 58 is locked with the lever member 60. In this case, the document S is held between the support glass plate 54 and the cover glass plate 58, and is held in the document cassette 50 without any slack.

Next, the document cassette 50 containing the desired document S
is inserted into the cassette insertion opening 14 from the cassette attachment/detachment section 12 of the image reading device 10. In this case, the identification mechanism 16 provided close to the cassette insertion opening 14 reads the code set in the cassette identification section 56 of the original cassette 50, and reads the code set in the cassette identification section 56 of the original cassette 50 and the original S stored in the original cassette 50. Identify the type of.

That is, the light emitted from the light emitting section 18 constituting the identification mechanism 16 passes through a predetermined light transmission section of the cassette identification section 56 and reaches the light receiving section 20, whereby the document cassette 5
0 and the type of document S are identified.

The document cassette 50 is mounted on a rotary table 46 by a guide roller 24 and a transport roller 26 that constitute the transport mechanism 22.
transported to. That is, the document cassette 50 is conveyed to the rotary table 46 while the conveyance roller 26 moves along the upper surface of the frame 52 of the document cassette 50. When the document cassette 50 is conveyed to a predetermined position on the rotary table 46, the document cassette 50
The rotation mechanism 44 is driven as necessary to adjust the angular position of the document S held in the document S, and the trimming mechanism 36 is driven as necessary to trim the document S.

That is, the trim base 40 is rotated under the driving action of the rotational drive source 38.
is displaced in a direction substantially perpendicular to the sub-scanning direction (arrow X direction), thereby mechanically performing the trimming operation of the document S.

On the other hand, after the document cassette 50 is positioned with respect to the document table 28, the rotational drive source 32 constituting the sub-scanning mechanism 30 is driven, and the document table 28 is rotated under the rotational action of the ball screw 34.
is conveyed in the sub-scanning direction (arrow X direction), and the light source 48 is energized.

In this case, the illumination light derived from the light source 48 passes through the original S in the main scanning direction, so that the image information recorded on the original S is extracted as an optical signal, and the image information as the optical signal is The light is guided to a photoelectric conversion unit 76 via a predetermined imaging lens 74 arranged on the optical axis. The photoelectric conversion unit 76 photoelectrically reads the image information as the optical signal.

During this time, the cover glass plate 58 of the document cassette 50 is applied with mechanical pressure by the cassette vibration mechanism 80.
It vibrates in the direction of arrow Y using hinge members 59a and 59b as fulcrums.

That is, when the document cassette 50 is transported in the direction of the arrow X by the sub-scanning mechanism 30 and the image reading section 70 starts reading the image S, the motor 82 of the cassette vibration mechanism 80 is also energized, and the rotational force of the motor 82 is Eccentric cam 8
4 rotates, and this rotational force causes the roller 86 to vibrate in the direction of arrow Y.

The vibration of the roller 86 causes the cover glass plate 58 to vibrate, and the gap between the cover glass plate 58 and the document S changes in synchronization with the vibration of the cover glass plate 58.

Newton rings, which occur when the distance between the cover glass plate 58 and the original S changes and there is a gap between them that corresponds to the wavelength of the reading light, repeat their generation and disappearance in synchronization with the vibration. . Therefore, the Newton ring image generated on the photoelectric conversion unit 76 during the image reading time is
This can be reduced compared to when no vibration is applied.

To explain this in more detail, the image projected onto the photoelectric conversion unit 76 is a composite image of the genuine image of the document S and the Newton's ring image.

Therefore, if the Newton ring image is changed within the image reading time, the image information in the photoelectric conversion unit 76 becomes substantially the same as the original S.

The image information obtained in this manner is reproduced in a reproduction device, and the reproduced image obtained thereby is a high-quality image without unevenness due to Newton's rings.

Note that the roller 86 that applies mechanical pressure to the cover glass plate 58 can obtain the same effect no matter where it is applied on the cover glass plate 58, as long as it does not interfere with the operation of other mechanisms. be.

Next, a second embodiment of a cassette vibrating mechanism 80 according to the present invention is shown in FIG.

This cassette vibration mechanism 80 has one end connected to the image reading device 10.
It consists of a shaft 94 which is fixed to and has a cam 92 attached to its other end.

Therefore, when the document cassette 50 is conveyed in the direction of the arrow X by the sub-scanning mechanism 30, the cam 92 in contact with the cover glass plate 58 of the document cassette 50 rotates in the direction of the arrow Z. Therefore, the cover glass plate 58 is subjected to mechanical pressure in the direction of arrow Y due to the unevenness of the cam 92. That is, the gap between the cover glass plate 58 and the document S can be changed, and as in the embodiment shown in FIG.
It is possible to obtain the effect of avoiding images with Newton rings.

Further, a third embodiment of the cassette vibration mechanism 80 is shown in FIGS. 5 and 6.

The image reading device 10 in the third embodiment includes a ladle drive circuit 100 that drives a piezoelectric element, which will be described later, and contacts 102a to 102d that slide on electrode plates of the piezoelectric element.

On the other hand, the cover glass plate 58 of the original cassette 50 has piezoelectric elements 104a to 104a whose shape changes when a voltage is applied.
04d, and electrode plates 106a to 106d of the piezoelectric elements 104a to 104d. The electrode plate 106a and the electrode plate 106b are insulated by an electrical insulator 108a, and similarly the electrode plate 106C and the electrode plate 106d are insulated by an electrical insulator 108b.

Next, its operation will be explained.

When the document cassette 50 is conveyed in the direction of arrow X, the contacts 102a to 102d touch the electrode plate 1 of the document cassette 50.
06a to 106d.

At this time, when the drive circuit 100 is energized to generate a voltage that changes over time, the voltage generated by the drive circuit 100 is applied to the contacts 102a to 102d and the electrode plate 106a.
Piezoelectric elements 104a to 104d via 106d
energize.

The piezoelectric elements 104a to 104d thus energized begin to expand and contract in the direction of the arrow Y.

Therefore, the gap between the cover glass plate 58 and the document S can be changed by biasing the piezoelectric elements 104a to 104d, and the Newton rings generated on the photoelectric conversion unit 76 during image reading time are not vibrated. can be reduced compared to

Note that the piezoelectric elements 104a and 104b and the piezoelectric element 10
4C and 104d may be energized at the same time, or
A similar effect can be obtained even if energization is performed with a time difference.

A piezo element is typically used as the piezoelectric element.

Also, when vibrating the cover glass plate 58, the document S
Even if the image reading unit 70 vibrates slightly in the direction of arrow Y, the image reading unit 70
It is clear that an amplitude within the depth of focus of is allowed without affecting the image quality of the original S to be read.

According to experiments, an example of the vibration period applied to the cover glass plate 58 was about 0.5 seconds, and the amplitude was preferably from several microns to more than ten microns.

[Effects of the Invention] According to the image reading device of the present invention, when reading image information held in a document cassette, oil is applied to fill the gap between the document and the holding member of the document cassette holding the document. By simply applying vibration to the cover glass plate without injecting it, in other words, by simply changing the size of the gap between the original and the cover glass plate, the effect of Newton's rings can be prevented, resulting in a uniform image. High-quality reproduced images can be obtained. Further, since there is no need to perform complicated operations such as injecting the oil and removing the oil after use, there is an advantage that efficiency of operations can be improved. It should be noted that although the supporting glass plate is cited as a preferred embodiment of the document cassette, it goes without saying that a flexible sheet body may be used in place of the supporting glass plate within the scope of the present invention.

[Brief explanation of drawings]

FIG. 1 is a schematic longitudinal sectional view of an image reading device according to the present invention, FIG. 2 is a perspective view of a document cassette loaded in the image reading device according to the present invention, and FIG. 3 is a schematic longitudinal sectional view of an image reading device according to the present invention. FIG. 4 is a perspective view of a second embodiment of the cassette vibration mechanism of an image reading device according to the present invention. FIG. 5 is a perspective view of a cassette of the image reading device according to the present invention. FIG. 6 is a perspective view of a third embodiment of the vibration mechanism; FIG. 6 is a longitudinal sectional view of the third embodiment shown in FIG. 5; 10... Image reading device 50... Document cassette 54... Support glass plate 58... Cover glass plate 80... Cassette vibration mechanism 82... Motor 84... Eccentric cam 86... Roller 104a to 104d... Piezoelectric element S... Original FIG, 5 FIG, 6

Claims (2)

[Claims] (1) two plate-like bodies, at least one of which is transparent, are placed close to each other, a document is placed between the plate-like bodies, and illumination light is irradiated onto the document; The document cassette for reading image information etc. carried by the document is provided with a vibration mechanism that applies temporally varying mechanical pressure to at least one plate-like body constituting the cassette. image reading device. (2) The image reading device according to claim 1, wherein the vibration mechanism for applying mechanical pressure is composed of a piezoelectric element.