JP3814416B2 - Image reading device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus configuration of an image reading apparatus that reads image information of an original such as a photograph or a document.
[0002]
[Prior art]
FIG. 5 is a schematic configuration diagram of a color image reading apparatus in the prior art.
[0003]
P is a read original placed on the original platen glass 100, and the image on the original is read by scanning the reading unit 101 in parallel with the original platen glass 100.
[0004]
As shown in FIG. 6, the reading unit 101 has a three-color LED 101R, 101G, 101B, which is a light source for irradiating a document, and images reflected light from the document on a light receiving element of the image sensor. A rod lens array 101L and an image sensor 101S are incorporated.
[0005]
The three color light sources are sequentially switched and turned on, and the image sensor reads the reflected light from the original for each color, thereby performing color separation reading.
[0006]
The reading unit 101 is fixedly supported on a slider 102 that slides on a guide shaft 103 fixed to the apparatus main body. A belt 104 that transmits power from a motor 105 that is a scanning drive source is fixed to the slider 102. By the forward / reverse rotation of the motor 105, the reading unit 101 can perform reciprocal scanning of the image reading range of the platen glass 100.
[0007]
In addition to the above components, the image reading apparatus includes an electrical component unit 106 including a control board and a power source. These components are arranged in a housing formed by a combination of an upper cover 112 and a lower cover 113 for fixing and supporting the document table glass.
[0008]
On the platen glass, a document cover 111 for pressing the document onto the glass is attached to be openable and closable.
[0009]
FIG. 7 is a block diagram of read image data processing by the image reading apparatus. The image output signal read by the image sensor 101S in synchronization with the sequentially blinking LED is sent to the amplifier 121 and amplified, and then converted into an image signal by the A / D converter 122.
[0010]
The A / D converter 122 divides the dynamic range of the image sensor (reading output difference between the pure white portion and the true black portion on the original) by the number of bits, and sets the number of gradations according to the brightness of the image on the original. assign. For example, when using an A / D converter with a resolution of 8 bits, the interval from white to black can be identified with 256 gradation levels, and with a 10-bit A / D converter, it can be identified with 1024 gradation levels.
[0011]
Therefore, an image reading apparatus using an 8-bit A / D converter can identify 24 bits = about 16.7 million colors in the case of cover reading with RGB three-color light sources, and 30 bits = about 1,074 million colors in the case of 10 bits.
[0012]
There are several types of image signal output forms of the image reading apparatus, and an output form suitable for the use of the read image can be selected.
[0013]
When reading the text and subjecting the contents to OCR, or reading a monochrome line drawing, a monochrome binary image is suitable. For example, an image signal obtained by lighting only G of the RGB light sources described above is used. In the image processing circuit incorporated in the gate array 123, image data binarized at a certain threshold value is used.
[0014]
When reading an image for the purpose of reading an image such as a photograph and outputting it to a monochrome printer, the image data binarized using halftone processing such as dithering and error diffusion using the image signal from the G light source. Is used.
[0015]
In the case of processing a color image, multi-value (24 bits, etc.) image data is suitable.
[0016]
The image signal that has passed through the image processing circuit is output to a device 200 such as a personal computer via the interface circuit 124.
[0017]
[Problems to be solved by the invention]
As a configuration of the housing of the above-described image reading apparatus, a configuration in which a resin upper cover 112 to which a document table glass 100 is attached is covered with a resin lower cover 113 on which components are placed.
[0018]
However, the resin cover is not only costly, but also has disadvantages such as low rigidity and difficulty in achieving dimensional accuracy.
[0019]
Accordingly, in order to ensure rigidity, it is necessary to cope with a design technique such as a structure in which a large number of reinforcing ribs are provided on the cover, or a structure on the component side to be placed is made strong and difficult to deform.
[0020]
In addition, since the component for scanning is placed on the lower cover 113, the upper cover 112 is interposed between the upper plate 112 and the original table glass 100 depending on the dimensional accuracy of the upper cover 112. There is a risk of affecting the scanning parallelism.
[0021]
The present invention has been made in order to solve the above-described problems of the prior art, and an object of the present invention is to provide an exterior of an image reading apparatus that is inexpensive and easily obtains dimensional accuracy and has high rigidity.
[0022]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a reading unit that scans under the platen glass to read an image of the original on the platen glass, supports the reading unit, and has an opening at the top. and a single frame in a box shape having, an image reading apparatus provided with the frame body is provided with a support portion for mounting the platen glass in the four sides, the side wall of one side of said four sides The document table glass is supported on both upper and lower surfaces by the arranged top surface and ribs .
[0024]
Further, according to the present invention, a reading unit that scans under the platen glass and reads an image of the original on the platen glass, and a box-shaped unit that supports the reading unit and has an opening at the top. An image reading apparatus including a frame, and the frame includes a support portion on which the document table glass is placed on four sides, and is disposed on a pair of opposing side walls on the four sides. The original platen glass is supported on both the upper and lower surfaces by a top surface portion and a rib .
[0027]
It is also preferable to fix the platen glass by attaching a glass retainer having an L-shaped cross section to the side wall having no top surface portion.
[0028]
It is also preferable that the frame is made of a resin material.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
Reference Example 1 A reference example will be described below with reference to the drawings. 1A and 1B are diagrams illustrating the configuration of an image reading device GR1 such as an image scanner according to Reference Example 1. FIG. 1A is a top view, and FIG. 1B is a cross-sectional view of the image reading device GR1. FIG. 1C is a cross-sectional side view of the image reading device GR1, which is a side view of the image reading device GR1 in the lateral direction, and is configured in a three-plane view with FIGS. 1A, 1B, and 1C. FIG.1 (d) is the figure which expanded the D1 part of FIG.1 (b).
[0031]
In the figure, P is a document placed on the document table glass 1, and the image information of the document P is read by scanning the reading unit 2 as image reading means in parallel with the document table glass 1.
[0032]
In the reading unit 2, a light source for irradiating a document similar to that described in FIG. 6, a lens for forming an image of reflected light from the document on a light receiving element of the image sensor, and an image sensor are incorporated.
[0033]
Reference numeral 11 denotes a frame that also serves as an exterior cover. In addition to the original platen glass 1 and the reading unit 2, a frame that guides the travel of the reading unit, a transmission mechanism that transmits a driving force to the reading unit, and a driving source. Various components (elements constituting the image reading means) such as a motor, a control board, and a power source are fixedly supported by a fixed support portion (such as a boss protruding from the bottom of the frame 11).
[0034]
The frame 11 has a box shape having an opening at the top, and the side walls 11a, 11b, 11c, and 11d are stepped portions as glass support portions for placing the document table glass 1 on the respective upper ends. 11e and an edge portion 11f facing the cut surface of the glass.
[0035]
After the above-described components are installed in the frame 11, the document table glass 1 is placed on the step 11 e inside the edge 11 f of the frame 11. Further, a plate 12 as a fixing member for attaching the platen glass 1 to the frame body 11 is placed, and the four corners as the engaging portions are fixed to the frame body 11 with screws (engaging means).
[0036]
As a result, the four corners and four sides of the frame 11 are in close contact with the document table glass 1, and a highly rigid housing is obtained. A square window portion 12a is provided at the center of the plate 12, and the platen glass 1 is exposed. Of the sides in contact with the window portion 12a, the two sides on the back and the right serve as the placement reference for the document P.
[0037]
The plate 12 may be fixed to the original table glass 1 with double-sided tape or the like in advance. As a result, the assembly workability can be improved.
[0038]
In this description, the side walls 11a, 11b, 11c, and 11d have been described as having a step portion 11e on which the platen glass 1 is placed. However, the present invention is not limited to this. Various forms of integrally forming the support portion for supporting the document table glass 1 with the frame 11 are conceivable.
[0039]
The effects of Reference Example 1 are as described below.
[0040]
First of all, a significant cost reduction can be achieved. In conventional image scanners, there are many examples in which the exterior cover is composed of an upper cover holding a platen glass and a lower cover on which other components are placed.
[0041]
The upper and lower covers belong to the most expensive category of image scanners,
Since the reference example 1 does not have the upper cover, the part cost is greatly reduced.
[0042]
Second, the dimensional accuracy and rigidity required for a single cover are greatly reduced. In the conventional configuration, in order for the device to perform its normal function, the lower cover, which is the base on which each component is placed, is molded with the required flatness, and can be placed on a distorted desk, for example. In order to maintain the function, the rigidity required to maintain the flatness was required.
[0043]
However, in Reference Example 1 , the platen glass 1 that also functions as the upper cover has both flatness and rigidity. Even if the flatness and rigidity of the lower cover, that is, the frame 11 in Reference Example 1 are somewhat insufficient, both the flatness and rigidity are sufficient when the platen glass 1 is fixed thereto.
[0044]
In addition, the cost reduction of the frame 11 which is the lower cover due to the relaxation of these requirements is so large that it cannot be overlooked.
[0045]
Reference Example 2 FIG. 2 shows an image reading apparatus GR2 having a structure in which the above-described reference example is improved in assembly workability and apparatus rigidity.
[0046]
2A is a top view of the image reading device GR2, FIG. 2B is a cross-sectional configuration diagram of the image reading device GR2 cut in the longitudinal direction, and FIG. 2C is a short view of the image reading device GR2. It is a side view and FIG. (B), (c) constitutes a three-sided view. FIG.2 (d) is the figure which expanded D2, D3 part of FIG.1 (b).
[0047]
In FIG. 2, reference numeral 22 denotes a glass pressing plate corresponding to the glass pressing plate 12 in Reference Example 1, and a square window portion 22 a through which the platen glass 1 is exposed is provided at the center, like the plate 12.
[0048]
Further, the bent portions on the four sides of the glass pressing plate 22 have hook portions 22b as engaging means at several places. The frame body 21 has a hook claw portion 21g as an engaging portion at a position facing the hook portion 22b of the glass pressing plate.
[0049]
The platen glass 1 is placed on the step portion 21e of the frame body 21, and the glass pressing plate 22 is fitted thereon so that the hook portion 22b is engaged with the claw portion 21g of the frame body 21, thereby forming a cover of the apparatus. Is done.
[0050]
Compared with the above-mentioned reference example 1 , the process of screwing the plate 12 can be reduced, and the assembly workability is improved.
[0051]
Furthermore, the side wall of the frame body 21 is likely to bend in a direction perpendicular to the height when the wall pressure is low or when the wall pressure is thin, but the bent portions of the four sides of the glass pressing plate 22 are aligned with the side wall. The occurrence of deflection is suppressed.
[0052]
Also in this reference example , workability can be improved by attaching the frame body 21 to the platen glass 1.
[0053]
In this figure, reference numerals 21a, 21b, 21c, 21d, 21e, and 21f corresponding to the constituent parts of the frame body 21 correspond to the constituent parts of 11a, 11b, 11c, 11d, 11e, and 11f of the frame body 11 of Reference Example 1. To do.
[0054]
(Embodiment 1 ) In the above reference example , only the lower surface of the document table glass is supported by the frame, but in this embodiment, the document table is placed on one of the four sides of the frame 31. A function to support both upper and lower surfaces of the glass was provided.
[0055]
FIG. 3 shows an image reading apparatus GR3 to which the present invention is applied. 3A, 3B and 3C are the same as those in FIGS. A side wall 31b on the front surface (right side in the figure) of the frame 31 has a top surface portion 31h and a rib 31i. With this shape, the frame 31 can be integrally formed by using a mold structure generally called an inner slide. The distance between the lower surface of the top surface portion 31h and the upper surface of the rib 31i is substantially equal to the thickness of the platen glass.
[0056]
The other three side walls 31a, 31c, 31d have the same shape as in the conventional example. The upper surface of the rib 31i on the front surface is in the same plane (same height) as the glass placement surface 31e on the side wall. As shown in the drawing, the front surface of the platen glass 1 is inserted between the top surface portion of the front portion of the frame and the rib (arrow 1) and lowered onto the placement surface (arrow 2).
[0057]
The glass presser 32 applied to the present embodiment is a U-shaped sheet metal having a hook similar to that of the reference example 2 as shown in FIG. After placing the platen glass 1 on the frame 31, the platen glass 1 is attached to the frame 31 to form a placement cover.
[0058]
In the above description, the top surface portion 31h configured integrally with the frame is provided on the front surface of the apparatus, but may be provided on the rear surface or side surface depending on the apparatus configuration.
[0059]
Also in the present embodiment, the four corners and four sides of the frame 31 are in close contact with the document table glass 1, and a highly rigid housing is obtained.
[0060]
According to the present embodiment, it is possible to further reduce the component cost and improve the assembly workability.
[0061]
In this figure, reference numerals 31a, 31b, 31c, 31d, 31e, and 31f corresponding to the components of the frame 31 correspond to the components 21a, 21b, 21c, 21d, 21e, and 21f of the frame 21 of Reference Example 2. To do.
[0062]
(Embodiment 2 ) The integral molding of the ceiling and the rib using the inner slide as described in the above embodiment is based on the structure of the mold, and a pair of opposing side walls (in this embodiment, the side walls 41b and It can be provided on the side wall 41d).
[0063]
When such a structure is adopted, the distance between the pair of side walls of the frame body 41 is set longer than the entire length of the platen glass 1, and the front side wall 41 b is further slid when the platen glass 1 is mounted. 41j is provided.
[0064]
As shown in FIG. 4, the front surface of the platen glass 1 is inserted between the top surface portion 41h of the front portion of the frame body and the rib 41i (arrow 1), and is lowered on the placement surface (arrow 2). The original table glass 1 is incorporated into the frame body 41 by inserting the rear surface of the original table glass 1 between the top surface portion 41j and the rib 41k at the rear of the frame body (arrow (3)).
[0065]
The glass platen 1 is fixed to the side walls 41a and 41c having no top surface by attaching a glass holder 42 having an L-shaped cross section to form an apparatus cover.
[0066]
As in the first embodiment, four corners and four sides of the frame body 41 is in close contact with the platen glass 1, the housing of high rigidity is obtained.
[0067]
In this figure, reference numerals 41a, 41b, 41c, 41d, 41e, 41f, and 41g for the components of the frame 41 are 31a, 31b, 31c, 31d, 31e, 31f, and 31g of the frame 31 of the first embodiment. Corresponds to the components of
[0068]
【The invention's effect】
According to the present invention as described above, one of the exterior covers that belong to the high-cost part of the image reading apparatus is reduced, and the exterior cover having one structure is reduced. Be lowered.
[0069]
In addition, the dimensional accuracy and rigidity required for the single cover are greatly reduced. In the conventional configuration, in order for the device to perform its normal function, the lower cover, which is the base on which each component is placed, is molded with the required flatness, and can be placed on a distorted desk, for example. In order to maintain the function, the rigidity required to maintain the flatness was required.
[0070]
However, in the present invention, the platen glass that also functions as the upper cover has both flatness and rigidity. Even if the flatness and rigidity of the lower cover, that is, the single frame body in the present invention are not good, both the flatness and rigidity can be sufficient when the original table glass is attached thereto.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of an image reading apparatus according to a first reference example .
FIG. 2 is a diagram illustrating a configuration of an image reading apparatus according to a second reference example .
FIG. 3 is a diagram showing a configuration of an image reading apparatus according to the first embodiment of the present invention.
FIG. 4 is a diagram showing a configuration of an image reading apparatus according to a second embodiment of the present invention.
FIG. 5 is an explanatory diagram of an image reading apparatus in the prior art.
FIG. 6 is a diagram illustrating the configuration of a reading unit.
FIG. 7 is a block diagram of read image data processing.
[Explanation of symbols]
1 Document glass 2 Reading unit (image reading means)
11 Frame 11a, 11b, 11c, 11d Side wall 11e Step part (glass support part)
11f Edge 12 Plate 12a Window (opening)
GR1 image reader

Claims (4)

A reading unit that scans under the platen glass and reads an image of the document on the platen glass;
A box-shaped single frame that supports the reading unit and has an opening at the top;
An image reading apparatus comprising:
The frame includes support portions for placing the document table glass on four sides, and supports the document table glass on both upper and lower sides by a top surface portion and a rib arranged on a side wall of one side of the four sides. An image reading apparatus. A reading unit that scans under the platen glass and reads an image of the document on the platen glass;
A box-shaped single frame that supports the reading unit and has an opening at the top;
An image reading apparatus comprising:
The frame includes support portions for placing the original table glass on four sides, and the upper and lower surfaces of the original table glass are provided by a top surface portion and ribs arranged on a pair of opposing side walls of the four sides. An image reading apparatus that supports the image reading apparatus. The image reading apparatus according to claim 2 , wherein the glass platen glass is fixed by attaching a glass retainer having an L-shaped cross section to a side wall having no top surface portion. The image reading apparatus according to any one of claims 1 to 3 wherein the frame member is characterized by being formed of a resin material.

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