JPS63111760A - Picture inputting device - Google Patents

Abstract

PURPOSE:To give an accurate white reference to a read unit by providing a white face to be installed slightly apart from a transparent board so as to avoid the gray coloring of the white face or production of interference fringes due to the close contact between the white face and the transparent board. CONSTITUTION:A shallow recessed part 20 is formed at the side of home position of the read unit 10 on the rear face of a retaining plate 3. The recessed part 20 is formed rectangle longer in the main scanning direction of an image sensor and the length is equal to the width of an original placing region 5. A bottom face 21 of the recessed part 20 is formed flat and a white sheet is adhered to the bottom face to form a white reference. Moreover, a comparatively short projection stripe 22 is formed to the recessed part 20 in the main scanning direction of the image sensor and the apex face is colored in black. The read unit is moved to read the bottom face 21 of the recessed part 20 at first and the result is set as the white reference level in reading an original, then the projected stripe mark is read and it is used as an original mark to read the original.

Description

DETAILED DESCRIPTION OF THE INVENTION An industrial field of application - The present invention relates to a raster scan type image input device that reads two-dimensional information on the surface of a document as an electrical signal, in which the document is placed on a transparent plate. , regarding the installation structure of a white reference during reading in an image input device configured to read the document with a reading unit that performs sub-scanning along this transparent plate, that is, a reference white area that provides a reference level of reading light to the reading unit. It is something.

1. Prior Art Image input devices generally use a one-dimensional image sensor as a photoelectric converter, and a white reference is provided to set the reference level of reading light given to the image sensor.

Conventionally, an image input device has a structure in which a transparent plate is provided as a document mounting table, and a reading unit equipped with an image sensor performs a reading operation while traveling along the transparent plate, as shown in FIG. 4 or 5. , white member 41.4
2 is attached to a transparent plate 2 to serve as a white reference.

Problems to be Solved by the Invention - In the one shown in FIG. 5, a white paint layer 41 is printed on the transparent plate 2 by screen printing, but as a similar structure,
There is also a structure in which a white sheet is adhered to the transparent plate 2. However, in a structure in which the white paint layer 41 or the white sheet is adhered to the transparent plate 2, as can be seen from the fact that when the white paper is wetted and brought into close contact with the glass surface, the adhered area appears gray, and the white paint layer 41a is attached to the transparent plate 2. The reflected light is biased considerably toward the gray side, and the luminous intensity decreases to about 90 to 70%, making it difficult to provide accurate white reference light to the image sensor. Further, in some cases, interference fringes may occur on the joint surface between the white paint N41 or the white sheet and the transparent plate 2, causing a serious problem in the quality of the white reference.

Therefore, as shown in Fig. 4, a white sheet 4 serving as a white reference is
2 may be mounted slightly above the surface of the transparent plate 2 using adhesive N43, but in this case, the gap 44
The adhesive layer 43 is placed on the white surface 42 to prevent dust from entering.
It is necessary to completely surround the area a and seal the gap 44. Especially in the manufacturing process of the device, such a delicate bonding process takes more man-hours and is more troublesome than a process such as screwing. A problem arises.

The present invention aims to solve the above-mentioned problems, and provides a perfect white standard to a reading device without causing graying or moire fringes on the transparent plate of a document table made of a transparent plate. This paper proposes an installation structure based on white standards, which has an hour wheel structure and is extremely easy to manufacture and assemble.

- Means for Solving the Problems - Explaining with reference to the reference numerals of the illustrated embodiments, in the structure of the present invention, the edge of the transparent plate 2 that serves as a support for the document 4 is separated from the main body frame 1. The holding plate 3 has a structure in which a white surface 21 is provided on the back surface, and the white surface 21 has a concave portion 20 on the back surface on the home position side of the reading unit 10.
, and the bottom surface of this recessed portion 20 is made white. If the holding plate 3 is made of white plastic, the white color on the bottom of the recessed part 20 may be the ground color of the holding plate 3; if not, a white sheet may be pasted on the bottom of the recessed part 20. Let it be the white surface 21.

The concave portion 20 is formed as a region with a completely defined periphery, and is formed so that the concave portion 20 is sealed by the transparent plate 2 when the pressing plate 3 is pressed against the transparent plate 2.

This white surface 21 is illuminated and read by the light source lamp 11 immediately after the reading unit 10 running along the transparent plate 2 starts from the home position, and is stored in the memory of the device as a reference for the light intensity level when reading the original 4. be done.

Since the white surface 21 is read immediately after the reading unit 10 starts from the home position, the recessed portion 20
An origin mark for the reading position when reading the original 4 can be provided within the area. This origin mark is formed by a thin protruding line 2 whose height is slightly lower than the depth of the recessed part 20.
2 is conveniently formed in a recess 20 and its top surface 23 is colored black by screen printing.

One effect: According to the above structure, the white surface 21 serving as a white reference is held with a slight gap 24 between it and the transparent plate 2. Graying of the white surface 21 and generation of interference fringes are avoided, and since the white surface 21 is provided in the concave portion 20 sealed by the transparent plate 2, dirt due to adhesion of dust etc. is avoided. do not have.

The white reference by this white surface 21 allows the concave portion 20 to be formed simultaneously when the holding plate 3 is formed, and in particular, the holding plate 3
If it is molded from white plastic, there is no need to attach a white sheet, etc., and the presser plate 3 can be attached to the main body frame l.
The manufacturing process is greatly simplified because the white reference is installed just by assembling it.

One Embodiment - Figures 1 to 3 show an embodiment of the present invention. In FIG. 2, which shows an overview of the overall structure of the image input device, 1 is a main body frame of the device, 2 is a transparent plate on the top surface of the main body frame, and 3 is a rectangular frame-shaped frame that holds the transparent plate 2 between it and the main body frame 1. The presser plate is fastened to the main body frame 1 with screws or the like, so that it presses the periphery of the transparent plate 2 and forms a placement area 5 for the document 4 in the center thereof.
is formed.

Reference numeral 6 indicates a guide rod mounted on the main body frame 1, 7 indicates a carrier slidably mounted along the guide rod 6, and 8
is a belt device that drives the carrier 7 back and forth. A reading unit 10 consisting of a light source lamp 11.11, an imaging lens 12, an image sensor 13, and a reflecting mirror 14 is mounted on the carrier 7. The position of the reading unit 10 shown in FIG. 2 is the home position, and the inner edge 31 of the holding plate 3 on the home position side and the inner edge 32 on the reference side side are abutment edges for positioning the document 4. It becomes.

On the back side of the holding plate 3, on the home position side of the reading unit 10, there is a shallow recess 2 shown in FIGS. 1 and 3.
0 is formed. This concave portion 20 has a rectangular shape that is long in the main scanning direction of the image sensor 13, and its length is equal to the width of the document placement area 5.

In the illustrated embodiment, a protruding strip 33 is formed in the shape of a rectangular frame on the back surface of the pressing plate 3, thereby forming a concave portion 20 surrounded by the protruding strip. The bottom surface 21 of the concave portion 20 is a flat surface, and this bottom surface is used as a white reference, and if the pressing plate 3 is not molded from white plastic, a white sheet is adhered to the bottom surface.

In the illustrated embodiment, the image sensor 1 is located in the concave portion 20.
A relatively short protrusion 22 in the main scanning direction of No. 3 is formed, and the top surface of the protrusion 22 is colored black by screen printing. Therefore, this protrusion 22 is read by the reading unit 10 as a short line segment in the main scanning direction, and its reading position becomes the origin when determining the reading area of the original 4.

Here, the reason why a convex line 22 is further provided on the recessed part 20 to serve as the origin mark is to position the top surface at the focal point of the reading unit 10 and to make it possible to color the book with black paint easily and accurately. This is for the purpose of

In the image input device having the above structure, the reading unit 1 starts moving from the home position in FIG. 2 to the right in the diagram.
0 is the position shown in FIG. 3 immediately after the start of movement, the bottom surface 21 of the concave portion 20 is read, and this is set as a white reference when reading the document 4. After reading the black color on the top surface of the protrusion 22 as an origin mark, an operation for reading the original 4 is started.

-Effects of the Invention- According to the configuration of the present invention explained above, as can be understood from the explanation in the operation section above, the installed white surface is provided slightly apart from the transparent plate, so that the white surface and Graying of the white surface and generation of interference fringes due to close contact with the transparent plate can be avoided, and an accurate white reference can be provided to the reading unit.

In addition, the concave portion of the presser plate can be easily formed when the presser plate is molded, and when the presser plate is molded from white plastic, it remains as it is, and when it is made of colored plastic, a white sheet is placed on the bottom of the concave portion. A white reference can be formed by simply attaching it to the body frame and assembling it to the main body frame. Therefore, the number of manufacturing steps for the device can be reduced and the device can be provided at a low cost. Furthermore, since the recessed part provided with the white surface is sealed by the transparent plate, it is possible to prevent dust etc. from entering the recessed part, and to avoid fluctuations in the reference level due to dirt on the white surface. .

[Brief explanation of the drawing]

Figures 1 to 3 are diagrams showing one embodiment of the present invention,
FIG. 1 is a cross-sectional perspective view of the main part seen from below, FIG. 2 is a cross-sectional view showing an overview of the entire apparatus, and FIG. 3 is an enlarged sectional view of the main part. 4 and 5 are side views showing a conventional white reference mounting structure. In the figure, 1: Main body frame 2: Transparent plate 3: Holding plate 4: Document 6: Guide rod 7: Carrier 10: Reading unit 20: Recessed part 21: White surface (bottom surface of recessed part) 22: Convex strip

Claims (2)

[Claims] (1) In a raster scan type image input device in which an image information reading unit sub-scans along a transparent plate serving as a document mounting table, a holding plate that holds the edge of the transparent plate between the frame of the device The image input device is provided with a shallow recess extending in the main scanning direction on the back surface of the reading unit on the home position side, and the bottom surface of the recess is used as a white surface for the white reference of the reading unit. (2) The image input device according to claim 1, wherein a long protrusion is provided in the recessed portion in the main scanning direction of the reading unit, and the top surface of the protrusion is made black to serve as a reference position mark for the reading operation. .