JPH02257761A - Picture reader - Google Patents

Abstract

PURPOSE:To suppress deflection of an original platen glass and to attain accurate reading by providing a reception part of a holding member supporting the vicinity of the end of the original platen glass while bending and raising the reception from a same surface of the holding member. CONSTITUTION:A frame 2 as a hold member of an original platen glass 1 is formed by folding four projections provided by cutting off four corners of a square sheet metal in the same direction as a side face part 3 and prescribed punching is applied to the surface part 4 of the frame 2 and a reception section 5 formed by punching is provided by folding and raising it in the opposite direction to the side face 3. The reception section 5 is supported in press contact in the vicinity of four ends of the original platen glass 1 to support the original platen glass in the facial direction. Thus, the error in the height of the reception section 5 is decreased, the deflection of the original platen glass 1 is suppressed and picture is read in an excellent way without defocusing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image reading device with a fixed document table, and particularly relates to an image reading device in which the reading means has a shallow depth of field.

[Prior Art] Conventionally, there is a member shown in FIG. 4 as a holding member for a fixed document table in an image reading device of a fixed document table type.

In this case, the original platen glass 101 is placed on a sheet metal frame 102 that serves as a holding member for the original platen glass 101, and this sheet metal frame 102 consists of two pairs of outer frames 102a and inner frames 102b. At the same time, a main support part 103 and a sub-support part 104 are formed by bending and raising the outer frame 102a and the inner frame 102b, respectively. The original platen glass 101 is held in the surface direction by contacting and supporting the original platen glass 101 .

[Problems to be Solved by the Invention] By the way, generally speaking, the variation in the thickness of the sheet metal frame 102 is ±0.08 mm as a forming error of members.

The error in the height of the support portions 103 and 104 is approximately ±0.2 mm.

Therefore, if there is a large difference in height between the support parts 103.104 of the sheet metal frame 102 in the conventional example, the document table glass 101 that comes into contact with the support parts 103.1f14 will not be stably held. Therefore, usually the support part 103
．． 104, one set of supporting parts (in this case, the supporting parts 103) facing each other is made parallel in height, and the height of the other set of supporting parts (in this case, the supporting parts 104) is adjusted by the above error. A method is used to lower the value.

However, in this method, although the document table glass 101 is stabilized by the supporting portion 103, since the outer frame 102a is placed on the inner frame 102b, the distance between the supporting portion 103 and the supporting portion 104 is a little less than 0.5 mm (0.2 2 +0.0
8), and a gap of approximately 0.5 mm is created between the document table glass 101 and the support portion 104. That is, when a heavy book or the like is placed on or pressed against the original platen glass 101, the original platen glass 101 bends in the direction of the arrow Y in the figure, and in an optical system using a normal lens, the depth of field is 0.7 mm. There is no problem because it is a certain degree, but the depth of field is 0.4mm like a short focus lens etc.
If you use an optical system that is only moderately accurate, it will not be possible to focus properly.

Therefore, as shown in FIG. 5, it is possible to insert wedges 105 (or shims) according to the gap between the supporting parts 104, but since the gap differs depending on the device, if this is done, the individual devices Adjustment is required. Therefore, the above-mentioned adjustment would not only reduce productivity but also increase costs, and could not be done in practice.

The present invention has been made in order to solve the problems of the prior art described above, and its purpose is to reduce the height error in the receiving part that supports the document table glass, and to reduce the load applied to the document table glass. The purpose is to suppress the deflection of the original platen glass and to perform accurate reading even when the document is being read.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a holding member that supports the vicinity of the edge of the document table glass and holds the document table glass in the surface direction; In an image reading device including a fixed document table having a holding member and a reading means for reading a document placed on the document table glass surface of the fixed document table, the holding member is attached to one side of the document table glass. It has at least one receiving portion, and this receiving portion is provided by bending and raising the same surface portion of the holding member.

[Function] In the present invention having the above configuration, the receiving portion of the holding member that supports the vicinity of the edge of the document platen glass is bent and raised from the same surface portion of the holding member, so that a plurality of When punching or bending the holding member, the process can be performed using a single cutting die or bending die, so it is possible to reduce the height error in the above-mentioned receiving part, and to reduce the deflection of the document table glass supported by this receiving part. can be suppressed.

[Embodiment] A first embodiment of the present invention is shown in FIGS. 1 to 3, and its configuration will be explained based on FIG. 1.

The frame body 2 serving as a holding member for the document table glass 1 is formed by cutting out four corners of a square sheet metal sheet and bending four convex portions in the same direction as the side surface portions 3. A predetermined die-cutting is performed on the surface portion 4 of the frame body 2, and a receiving portion 5 formed by the die-cutting is bent and raised in a direction opposite to the side surface portion 3.

Here, the receiving part 5 is for supporting the document table glass 1 in the vicinity of the four edges thereof and holding the document table glass 1 in the surface direction. A pair of supporting sides 5a that support the base glass 1 in the longitudinal direction;
It consists of a pair of support ends 5b that support in the lateral direction. Longitudinal guide pieces 6 are protruded from both sides of the negative support side 5a, and a longitudinal pressing tool 7 is attached to the rear of the center of the other support side 5a with a screw. Short guide pieces 8 are protruded from both sides of the one support end 5b, and a short push tool 9 is attached to the rear of the center of the other support end 5b by screws. The document table glass 1 is held in the horizontal direction by the longitudinal pressing tool 7 and the short pressing tool 9.

Next, the overall configuration and operation example of this embodiment are shown in FIGS. 2 and 3.
This will be explained based on the diagram.

A pressure bonding plate 11 is provided on the glass platen surface of the fixed document platen 10 for tightly contacting a document whose image is to be read to the glass platen surface. Inside the frame 2 that holds the document table glass 1, a reading means 14 consisting of a short focal length lens array 12 and a sensor 13 is provided.
A main scanning carriage 16 including a lamp 15 for illuminating the document is provided, and a sub-scanning carriage 17 including the main scanning carriage 16 is also provided. Furthermore, this main scanning carriage 16 is driven by a main scanning motor 1.
8 and the main scanning belt 19, the main scanning rail 2o
The sub-scanning carriage 17 is movable in the horizontal direction (main scanning direction) on the top thereof, and the sub-scanning carriage 17 is driven by a sub-scanning motor 21 . The sub-scanning belt 22 and the support rollers 23 allow movement on the sub-scanning rail 24 and the support roller rail 25 in the vertical direction (sub-scanning direction).

That is, a document whose image is to be read is placed on the first surface of the document table glass of the fixed document table 1O, and the document is pressed with the pressure bonding plate 11 to bring it into close contact with the first surface of the document table glass. The image information is read by the reading means 14 scanning the surface.

Here, the sub-scanning rail 24 is adjusted so that the error at a predetermined height with respect to the receiving portion 5 is ±0.05 mm or less, and the support roller rail 25 is also adjusted so that the error at a predetermined height with respect to the receiving portion 5 is ±0.05 mm or less. It is adjusted and fixed to be within ±0.05mm. Further, the short focus lens array [2] of the main scanning carriage 16 and the sensor 13 are independently adjusted to a predetermined median value, and the height of the main scanning rail 20 and the sub scanning rail 24° support roller 23 is adjusted independently. The variation error is ±0.05 mm. In other words, the height variation error between the support side 5a and the sensor 13 is ±O,L.
mm (0.05+0.05).

The supporting end 5b of the receiving part 5 is also at the same height as the supporting side 5a, and since these are provided by bending and raising the same surface part 4 of the same member, the variation thereof is ±0.08 m.
It is m.

Therefore, an error of a maximum of a little less than 0.2 mm (0.1+0.08) occurs between the document table glass 1 and the sensor 13, but the depth of field of the short focus lens array 12 is 0.2 mm.
Since it is within the range of 4 mm, there is no problem.

In this embodiment, the document is scanned separately into main scanning and sub-scanning, but the reading sensor may be made wider and reading may be performed by scanning in one direction.

Also, the shape of the receiving part that supports the original platen glass.

Regardless of the form of this embodiment, the entire side end face may be used or a part thereof may be used.

[Effects of the Invention] As explained above, the present invention provides a reading means with a shallow depth of field by reducing the height error in the receiving portion and suppressing the deflection of the document platen glass supported by the receiving portion. Even in image reading devices using
Good image reading can be performed without losing focus.

Furthermore, since the holding member can be punched and bent in one step, the manufacturing process can be simplified and costs can be reduced.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the main parts of an embodiment of the present invention, Fig. 2 is a sectional view showing the overall configuration of this example, Fig. 3 is a perspective view showing the main parts of Fig. 2, and Fig. 4 is a perspective view showing the main parts of the embodiment of the present invention. FIG. 5 is a perspective view showing the main parts of the conventional example, and FIG. 5 is a sectional view showing another conventional example. Reference numeral 1... Original table glass 5... Receiving portion 7... Longitudinal pressing tool 9... Description of short pressing tool 2... Frame body (holding member) 6... Longitudinal guide piece 8.・・Short guide piece Figure 3 Fake 1i1 House Figure 5

Claims (1)

[Scope of Claims] A holding member that supports the vicinity of the edge of a document table glass and holds the document table glass in the surface direction, a fixed document table having this holding member, and a document table glass of this fixed document table. In an image reading device equipped with a reading means for reading a document placed on a surface, the holding member has at least one receiving portion on one side of the document platen glass, and this receiving portion is a part of the holding member. An image reading device characterized in that the same surface portion is bent and raised.