JPS6218166A - Contact type image sensor - Google Patents

Abstract

PURPOSE:To read the white surface of a drive roller when the width of an original is narrower than the reading width and to read regions at the outside of the original as a white level by using an LED illumination light source and fitting the light source to the opposite side to the roller shaft position with a sensor read shaft. CONSTITUTION:The original 1 runs toward the arrow by an original drive roller 6. In lighting the original face by the LED illumination light source 2, the reflected light component is led to a photodetector 3 through a near convergent fiber light guide system 4 to display the original picture onto the photodetector 3. When the original width is narrower than the reading width, the light from the light source 2 at the part at the outside of the original lights the drive roller 6. Since the path of the major component of the light is close to the path of the original face, the reflected light component of the white part of the surface of the roller 6 enters sufficiently the convergent fiber light guide system 4 so as to attain the region at the outside of the original as a white color.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a contact type image sensor used for reading documents in facsimiles and the like.

[Conventional technology]

FIGS. 3 and 4 are cross-sectional views showing conventional contact image sensors. In the figures, (1) is a document, (2) is an LED illumination light source that illuminates the document, (3) is a light receiving element, and (4) is a light receiving element. ) is a focusing fiber light guide system that guides the original image to the light receiving element.
(5) is a document guide, and (6) is a document drive roller with a white surface, which is pressed against the document guide (5) by a spring. In FIG. 4, only one LED illumination light source (21) is installed on the entrance side of the document travel path from the reading point.

Next, the operation will be explained. In Figure 3, the manuscript (1
) travels in the direction of the arrow shown in FIG. 3 as the document drive roller (6) is rotated in the direction of the arrow by the document guide (5) and the document drive roller (6). LE this manuscript side
Illumination is provided by the D illumination light source (2). The light illuminates the document surface along a path shown by a solid line, and a reflected light component shown by a dotted line is guided to a light receiving element (3) by a focusing fiber light guide system (4), and an image of the original is projected onto the light receiving element (3).

In addition, by improving the performance of the LED illumination light source (21), the illuminance of the document surface is increased, and by improving the light receiving element to increase the sensitivity, as shown in Figure 4, only one LED illumination light source (2) can be used. An attached contact type image sensor has also been devised, but due to the configuration of the apparatus, it is attached to the entrance side of the travel path for the document (1).

[Problem that the invention seeks to solve]

Since the conventional contact type image sensor is configured as described above, it is necessary to install two LED illumination light sources, which is expensive. In addition, if only one wire is attached to the entrance side of the document travel path as shown in Figure i4, when the width of the document is narrower than the bush removal width of the light-receiving element (3), the part outside the document will be As shown in , the main component of the light emitted from the LED illumination light source passes through the document drive roller (6) along the path shown by the solid line.
As a result, the reflected light component is greatly separated from the light path on the document surface shown in Figure 4, and the reflected light component that enters the focusing fiber light guide system (4) is reduced, and the reflected light component is reflected on the surface of the document drive roller. There were problems such as the white color could not be read and the outside of the document was read as black.

Was this invention made to solve the above problems? An object of the present invention is to obtain a contact type image sensor which can use only one LED illumination light source, and which can also read the white color on the surface of a document drive roller and read the outside of the document as white.

[Means for solving problems]

The contact type image sensor according to the present invention includes a single LED illumination light source, and its mounting position is provided on the opposite side of the roller axis position with respect to the sensor reading point.

[Effect]

The LED illumination light source in the present invention illuminates the document drive roller, which has a white surface outside the document, so that it can be read as white even when the inside of the document is narrower than the reading width.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (1) is the original, and (2) is the original from the reading point (
1) Only one LE installed on the exit side 1 of the running path
D illumination light source, (3) is a light receiving element, (4) is a light receiving element (3
) is a focusing fiber light guiding system (5) that guides the original image to the original document guide, and (6) is an original driving roller with a white surface.

Next, the operation will be explained. The 1 quintillion manuscript (1) has a document guide (5) and a document drive roller (6) that rotates in the direction of the arrow.
The vehicle travels in the direction of the arrow shown in FIG.

This document surface is illuminated by an LED illumination light source 21. The light illuminates the document surface along the path shown by the solid line, and the reflected light component shown by point Km is sent to the light receiving element (3) by the focusing fiber light guide system (4).
The document image is projected onto the light receiving element (3).

When the inside of the document is narrower than the reading width, the light emitted from the LED illumination light source (2) illuminates the document drive roller (6) in the area outside the original Q along the path shown by the solid line in FIG.

Since the path of the main component of light shown in FIG. 2 is close to the path on the document surface shown in FIG. ), and the outside of the document can be read as white.

In addition, in the above embodiment, the LED illumination light source (2
), but other illumination sources such as fluorescent lamps may also be provided.

Furthermore, in the above embodiment, an example was described in which the white document driving roller (6) was arranged on the entrance side of the document running path from the reading point, but it is also possible to arrange the white document driving roller (6) on the exit side of the document running path from the reading point. In this case, the LED light source (2) is arranged closer to the entrance of the manuscript path than the reading point.

〔Effect of the invention〕

As described above, according to the present invention, one LED illumination light source is used.
The device is made of wood and is mounted on the opposite side of the sensor reading axis from the roller position, which allows the device to be made at low cost. This has the effect of being able to read the white color on the surface of the document drive roller and read the outside of the document as white.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a contact type image sensor according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of the path of illumination light outside the document according to the present invention. FIG. 3 and FIG. 4 are cross-sectional views showing a conventional contact type image sensor. FIG. 5 is an explanatory diagram of the path of illumination light outside the document of a conventional contact type image sensor. (1) is the original, (21 is the LED illumination light source, (3) is the light receiving element, (4) is the focusing fiber light guide system, and (5) is the original.
YFJ guide, (6) is the document drive roller. In addition, in the figures, the same symbols indicate the same or equivalent parts.

Claims (1)

[Claims] An illumination light source that is disposed opposite to a roller that conveys the document and illuminates the document, a fiber light guide system that focuses and guides the reflected light, and a light receiving element provided at the other end of the fiber light guide system. and a contact type image sensor for reading a document image of the document, wherein the surface of the roller is formed white, the roller axis is offset from the reading axis of the contact image sensor, and the illumination light source is arranged to read the image of the document. A close-contact type image sensor, characterized in that it is provided on a side of the shaft opposite to the roller shaft side.