JPS6065661A - Original reader - Google Patents

Abstract

PURPOSE:To prevent the deterioration of quality of a reference face by forming the reference face on an original platen. CONSTITUTION:A white coating film 12 for the reference face is coated directly onto the side face opposite to a lighting light source 7' by clipping an original platen 11 of a prolonged part. The illuminating light source 7' is lighted simultaneously when a read start signal enters, the lighting of the illuminating light source 7 transmits through the original platen 11 and touches the white coating film 12, the light is reflected succeedingly and reaches a reflecting mirror 3' to attain a prescribed reading level setting. Since the white coating film 12 is covered entirely by an original platen pressing plate 13, the film 12 does not directly contact external air.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a document reading device that breaks down image information on a document into minute parts and reads them as electrical signals.

<Prior Art> Recently, in addition to the conventional processing of code information, processing as image information has been implemented.

In this image processing (per C), the document reading device functions as an input section for inputting image information.In the above-mentioned document reading device and 1-, the input section of a facsimile machine was initially used. However, as there is a demand for inputting image information at higher speed and with greater precision, dedicated document reading devices have come into use.

Furthermore, there is now a need for a document reading device that can suitably handle various kinds of documents, such as book-shaped documents, without being limited to sheet-shaped documents.

Here, the general structure of the document reading device will be explained.

A line image sensor in which a plurality of pixels are arranged in a straight line is used as a reading element. The representative one is I
It is a C-sensor CCD line image sensor.

The length of the sensor is usually less than 30 lengths.

On the other hand, the reading width of a document is, for example, the short side of A3 paper is 29
The image size is as wide as 7fi, so an optical system is required to form a reduced image of the original onto the pixels of the sensor. , A lens unit composed of a plurality of lenses is used as this optical system.

Further, the reading surface (C) of the document is irradiated with light from an illumination light source such as a norogen lamp or a fluorescent lamp.

The above document, sensor, lens unit, and illumination light source move relative to each other in a direction perpendicular to the reading line, and correspondingly, electrical signals corresponding to the contents of the document are sequentially extracted from the pixels of the sensor, and as a result, the document The content information is converted into electrical signals.

Methods for relatively moving the document, sensor, lens unit, and illumination light source include a method in which the document is moved using a feed roller, a method in which the document table with the document placed thereon is moved, and a method in which the document is fixed and the lens is moved. The unit, sensor, and lighting source are all 1. There are two methods: one in which the document, lens unit, nose and sensor are fixed, and the reflection mirror and illumination light source in the optical path are moved.

Therefore, the above-mentioned document reading device in which the reflection mirror and the illumination light source move in the middle of the optical path will be discussed.

Figure @1 shows the structure of the document reading device.

In FIG. 1, a document 1 is placed on a document table 2 made of transparent glass. At this time, the original 1 is placed so that the surface to be read is in contact with the original table 2.

The image of the original 1 on the original platen 2 passes through the anti-fouling mirror 3 and the reflective mirror 4, and is formed as a reduced image on the pixel surface of the reading element section 6 by the reading lens unit 5.

When the reading of the original is started, the illumination light source 7 starts to move and illuminates the reading part of the original 1 through the original table 2 with a brightness that allows the reading element section 6 to sufficiently read the information of the original image.

Subsequently, the illumination light source 7 and the reflection mirror 3 start moving in the direction indicated by arrow A while maintaining the same distance from the original 1.

In synchronization with this, the reflecting mirror 4 starts moving in the direction of arrow B by a moving amount (half the speed) that is half the moving amount of the illumination light source 7 and the reflecting mirror 3.

Therefore, the optical path length from the original surface to the reading element part 6 inches remains the same ((() is maintained regardless of the movement 1C of the illumination light source 7 and the separation mirrors 3 and 4).

In this way, information on the document surface is transmitted to each pixel on the reading element section 6 by moving the illumination light source 7 and the reflection mirror 3 below the document 1 from right to left in the figure.

At this time, an electrical signal is extracted in accordance with the brightness of the image formed from the reading element section 6 at a timing corresponding to the amount of movement of the illumination light source 7 and the reflecting mirror 3.

When the document reading is completed, the illumination light source 7 is turned off,
The illumination light source 7 and the reflecting mirrors 3 and 4 start moving in the opposite direction to the reading direction and return to their initial set positions.

However, fluorescent lamps are generally used as the illumination light source 7, but since the light intensity of fluorescent lamps decreases at the filament portions at both ends of the tube, the illuminance is not the same in the high reading portions, and At the mountain pass, the illuminance is low.Furthermore, the light passing through the reading lens unit 5 gradually decreases as it goes from the center of the lens to the periphery. The pixels of the sensor of the reading element 6 facing the central part of the lens + C and the pixels of the sensor facing the peripheral part of the lens (C facing each other) may differ depending on the location, for example when reading a uniform white area over the entire surface. The amount of light received by the sensor is not constant, and therefore the output of the sensor differs for each pixel.

Therefore, a correction circuit is incorporated which stores the reliability level when reading a white background in this manner and determines whether this reliability level is the white level.

The white reference portion 8 in FIG. 1 is the level of this white background. This white reference portion 8 is located at the point where each pixel of the sensor is in focus when the reading device is waiting for a reading command.

This white reference portion 8 is exposed inside the reader main body, and paint is applied to the cover 9 of the reader.
Alternatively, it may be created by gluing rubber plates, resin plates, etc.

Therefore, when the cover 9 is attached or removed, the white reference portion 8 may be contaminated by dust or dirt generated on the cover 9, or the color may fade due to changes over time. Deterioration in reading quality could not be avoided.

<Object of the Invention> In view of the above, the present invention has a document table on which a document is placed, and a reference surface forming body, and the reference surface is set opposite to the reference surface so that the reading reference level can be determined by a light amount of 1. The purpose of the present invention is to improve the structure of the reference surface in a document reading device that does not cause quality deterioration.

Embodiment> A reading reference level is set based on the reference surface on the document table.

One embodiment of the present invention will be described.

FIG. 2 is a partial structural diagram of the document reading device according to this embodiment.

In the figure, ten originals are placed on an original table 11 made of transparent glass.

In this embodiment, the document table 11 extends from the end of the portion where the document 10 is placed.

The extended portion is provided at a position facing the illumination light source 7'.

A white coating film 1 as a reference surface is placed on the opposite side surface of the stretched portion of the document table 11 where the illumination light source 7' is provided.
2 is directly coated.

The coating $4VC of this white coating film 12 was made of synthetic resin.

Due to this structure, in this embodiment, the illumination light source 7' lights up at the same time as the reading start signal is received.
The light emitted from the illumination light source 7' passes through the original platen 11, hits the white coating film 2, and is then reflected to the reflection mirror 3.
', the same optical path as described above is followed, and a predetermined reading level setting (white level correction) is performed.

Next, the illumination light source 7' and the reflection mirror 3' start moving in the direction of arrow A, and read the original.

Note that the white coating film 12 is completely covered by the original plate pressing plate 13 (in the figure, the original plate pressing plate 1
3 and the white coating film 12, or in fact (in reality, they are in close contact with each other), there is no direct contact with the outside air.

In order to avoid air contact of this white coating film 12,
As shown in the figure, the protective film 1 is wrapped around the white coating film 12.
It is also possible to form 4.

In the above embodiments, the paint is white, but of course it is easy for a person skilled in the art to use paint of other colors (C
As you might imagine, this paint is also a synthetic resin-based E/(
It is not limited to j.

'iJ+: Sukkatsuru ((, The reference surface is also not formed by a coating film, but by adhesion of a rubber plate, a resin plate, etc.)

It can also be formed.

Effects> As described above, according to the document reading device of the present invention, there is no change in color such as fading or discoloration caused by the reference surface coming into contact with air, and there is no space between the reference surface and the document table. Since there is no intrusion of dirt, dust, etc., a good reference surface can be maintained at all times.

, 4. Brief description of the drawings FIG. 1 is a structural diagram of a conventional document reading device, FIG. 2 is a partial structural diagram of the document reading device of the present invention, and FIG. 3 is a part of the document reading device of the present invention. FIG. 3 is an improved partial structure diagram.

DESCRIPTION OF SYMBOLS 10... Original document, 11... Document table, 12... White coating film, 13... Original, striped stand press plate, 14... Protective film.

Claims (1)

[Claims] 1. In a document reading device that has a document table on which a document is placed and a reference surface forming body, and sets a reading reference level based on the amount of light reflected from the reference surface, the reference surface is A document reading device characterized in that it is formed on the document table. 2. The document reading device according to claim 1, wherein the reference surface forming member is a paint film, and the paint is formed by applying it onto the document table.