JP2001154290A - Image reading device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To close a document on a platen glass when a document cover is closed on a main body of an image reading apparatus to read a clear image. A suction cup is provided at an end of a document cover, and the suction cup causes the document to be in close contact with a platen glass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus for reading an image of a document such as a photograph or a document, converting the image into digital data, and outputting the digital data.

[0002]

2. Description of the Related Art FIG. 5 is a schematic structural view of a conventional color image reading apparatus.

[0005] P denotes a document to be read placed on the document glass 100, and an image on the document is read by scanning the reading unit 101 in parallel with the document glass 100.
As shown schematically in FIG. 6, the reading unit 101 includes three color LEDs 101R, 101G,
01B, a rod lens array 101L that forms an image of light reflected from a document on a light receiving element of the image sensor, and an image sensor 101S are incorporated.

The light sources of the three colors are sequentially switched and turned on, and the image sensor reads the reflected light from the document for each color, thereby performing color separation reading of the image of the document.

A reading unit 101 is a slider 102 which slides on a guide shaft 103 fixed to the main body of the apparatus.
Fixedly supported on top.

A belt 104 for transmitting power from a motor 105 as a scanning drive source is fixed to the slider 102. By the forward / reverse rotation of the motor 105, the reading unit can perform reciprocal scanning in the range of the document table glass 100.

[0007] In addition to the above configuration, this color image reading apparatus has an electrical unit 106 comprising a control board and a power supply.
There is. These components are arranged in a cover 110 that fixedly supports the document table glass 100.

A document cover 111 for pressing a document onto the glass 100 is provided on the document table glass 100 with a concave portion 110a provided at the rear end of the upper surface of the apparatus main body and a convex portion at the rear end of the document cover 111. It is mounted to be openable and closable, with a mating portion with 111a as a fulcrum.

The original table glass 1 on the inner surface of the cover 111
The sheet material 112a and the sponge 1
An original pressure bonding sheet made of 12b is stuck.

[0010]

The above-described reading unit 101 in which a light source and a lens array are integrated is extremely compact, but has a shorter proof distance than conventional optical systems, and has a smaller depth of focus. It had the disadvantage of being shallow.

Therefore, in order to read the original clearly, it is necessary to bring the original close to the original platen glass 100.

However, in the case of an original having folds and curls, the original cannot be brought into close contact with the original platen glass 100, and the image of the floating portion becomes dark or blurred. The problem had arisen.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is an image for scanning an image of an original placed on an original platen glass under the original platen glass in parallel with the image. In an image reading device that is read by a reading unit,
A document cover provided to cover the platen glass, a flexible sheet member for pressing the document on a surface facing the platen glass, and a document cover provided to be openable and closable with respect to the platen glass; The cover is provided with a suction cup for bringing the flexible sheet member into close contact with the platen glass.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 are views showing the configuration of a color image reading apparatus according to the present invention.

In FIG. 1, reference numeral P denotes a document to be read placed on the platen glass 1, and an image of the document is read by scanning the reading unit 20 in parallel with the platen glass 1.

As shown in FIG. 5, a three-color LED 20R, which is a light source for illuminating the original, is provided in the reading unit 20.
20G and 20B, a rod lens array 20L for forming an image of reflected light from a document on a light receiving element of the image sensor, and an image sensor 20S are incorporated.

Reference numeral 11 denotes a frame body which also serves as an exterior cover, in which, in addition to the original platen glass 1 and the reading unit 20, a rail for guiding the running of the reading unit 20, a reading unit 2
A transmission mechanism for transmitting a driving force to the motor 0 and a motor as a driving source,
Contains control board, power supply, etc.

An original cover 12 for pressing an original is fitted on the original platen glass 1 with a concave portion 11a provided at the rear end of the main body outer casing 11 and a convex portion 12a at the rear end of the original cover 12. It is attached so that it can be opened and closed with the part as a fulcrum. An original cover 13 made of a sheet material 13a and a sponge 13b is adhered to the inner surface of the original cover 12 facing the original table glass 1.

Further, a suction cup 14, which is a feature of the present invention, is attached to the leading end of the document cover 12. Further, in the position of the frame body 11 facing the suction cup 14, the suction cup 1 is provided.
4 is finished to a smooth surface so that it can easily adhere.

The sponge 13b has such a thickness that the original cover 12 is closed and the suction cup 14 is slightly crushed in a state where the suction cup 14 is in close contact with the frame 11.

FIG. 6 is a block circuit diagram of the image reading apparatus.

The image output signal read by the image sensor 20S in synchronization with the sequentially blinking LED is output to the amplifier 12S.
After being sent to 1 and amplified, it is converted into a digital image signal by the A / D converter 122. The A / D converter 122 divides the dynamic range of the image sensor 20S (the read output difference between the pure white part and the pure black part on the document) by the number of bits, and performs gradation according to the brightness of the image on the document P. Assign a number. For example, when using an 8-bit resolution A / D converter, the interval between white and black is 25%.
When a 10-bit A / D converter is used for 6 gray levels, it can be identified as 1024 gray levels.

Therefore, in an image reading apparatus using an 8-bit A / D converter, 24 bits = approximately 16.7 million colors and 10 bits in color reading using a light source of three colors of RGB.
In this case, 30 bits = approximately 1.074 billion colors can be identified.

There are several types of image signal output modes of the image reading apparatus, and an output mode suitable for the use of the read image can be selected.

When reading a text and applying the content to OCR or when reading a monochrome line drawing, a monochrome binary image is suitable, and it is obtained by lighting, for example, only G among the above RGB light sources. The image signal is transmitted to the gate array 12
The image processing circuit incorporated in 3 has a threshold value of 2
Valued image data is used.

When reading an image such as a photograph and outputting the image to a monochrome printer, the image is binarized using a halftone process such as a dither method or an error diffusion method using an image signal from a G light source. Image data is used. When processing a color image, multivalued image data is suitable.

The image signal that has passed through the image processing circuit is sent to a device 20 such as a personal computer via an interface circuit 124.
Output to 0.

According to the first embodiment, the original is placed on the original platen glass 1, the original cover 12 is closed, and the suction cup 14 is closed.
When pressed from above, it comes into close contact with the frame 11. At this time, the sponge 13b bends, and the reaction force is applied to the sheet material 13a.
Therefore, even if the original has wrinkles or curls, it is stretched and adheres to the glass. Therefore, a clear image can be read.

The force applied to the document can be set to an appropriate value according to the amount of deflection of the sponge and the suction force of the suction cup.

Further, in the present embodiment, the structure in which two suction cups are placed at the open end of the document cover 12 has been described. Can be handled.

Further, a suction cup can be attached to the frame 11 side.

(Embodiment 2) The original cover using the suction cup in Embodiment 1 described above requires a large force to open. Therefore, in the second embodiment, this point is improved, and the original cover can be easily opened.

The configuration of the document cover 12 is the same as that of the first embodiment. As shown in FIG. 3, in the suction cup 14 of the second embodiment, a peeling projection 14a is integrally provided near the outer periphery thereof, and the tip of the projection 14a is further attached to the original cover 1.
Attach to 2.

With the above construction, when the handle of the document cover 12 is lifted, the projection 14a is lifted up and the outer periphery of the suction cup is peeled off.
Can be easily opened.

(Embodiment 3) In Embodiment 3, the ease of opening the original cover 12 of Embodiment 2 is improved.

As shown in FIG. 4, a band-like portion 14 having a length corresponding to substantially the entire width is provided at a front end portion serving as a handle portion of the document cover 12.
b is fixed to the document cover 12 at several places. The band portion 14b is connected to the outer peripheral portion of each suction cup via the protrusion 14a.

No matter where the front end of the document cover 12 is lifted, the protrusion 14a is lifted and the outer periphery of the suction cup is peeled off, so that the cover can be opened more easily.

[0039]

As described above, according to the present invention, the original cover is brought into close contact with the original placed on the original platen glass by the suction cup, so that the original has wrinkles and curls. Can also be stretched and adhered to the platen glass, enabling clear images to be read.

Further, since a peeling projection is integrally provided near the outer periphery of the suction cup, and the tip thereof is attached to the document cover, the protrusion is lifted when the document cover is lifted, so that the suction cup is easily peeled. And the original cover can be easily lifted.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of an image reading apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a document cover of the image reading apparatus according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a configuration of a document cover of an image reading apparatus according to a second embodiment of the present invention.

FIG. 4 is a diagram illustrating a configuration of a document cover of an image reading apparatus according to a third embodiment of the present invention.

FIG. 5 is a diagram illustrating a configuration of a reading unit of the image reading apparatus according to the first embodiment of the present invention.

FIG. 6 is a block circuit diagram of the image reading apparatus according to the first embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a conventional image reading apparatus.

FIG. 8 is a diagram showing a configuration of a reading unit of a conventional image reading apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 platen glass 2 reading unit 11 frame 12 document cover 13 document pressure sheet 14 sucker 14 a projection

Claims (4)

[Claims] 1. An image reading apparatus for reading an image of a document placed on a platen glass by image reading means for scanning under the platen glass in parallel with the platen glass, provided to cover the platen glass. A document cover having a flexible sheet member for pressing the document on a surface opposite to the document cover, the document cover being provided to be openable and closable with respect to the platen glass, and An image reading apparatus comprising a suction cup for adhering a flexible sheet member. 2. The image reading apparatus according to claim 1, wherein the flexible sheet member has a thickness that bends by a predetermined amount when the original cover is closed and fixed as a suction cup. apparatus. 3. The image reading apparatus according to claim 1, wherein a projection is provided on an outer peripheral portion of the suction cup, and the projection is connected to the document cover. 4. A projection is provided on an outer peripheral portion of the suction cup, and the projection is connected to a belt-like body attached substantially over an entire area of an end serving as a handle of the document cover. The image reading device according to claim 1, wherein: