JPH04150661A - Original reader - Google Patents

Abstract

PURPOSE:To uniformize the density of a reading picture by interrupting light from a light source opposite to a photodetector surface when reading out an original, interrupting the light from the light source opposite to the original surface when correcting picture information, and arranging a movable object for interrupting an optical path which a photodetector is irradiated with a direct light from the light source arround the light source. CONSTITUTION:A light source 2 is arranged so that both of an original 4 surface is irradiated with the light and a photodetector 6 surface. When reading out the original 4, by rotating a movable object 7 for interrupting an optical path between the light source 2 and the photodetector 6, the light opposite to the photodetector 6 is interrupted and the original 4 is read out, and when correcting the picture information, by rotating the movable object 7 for interrupting the optical path between the light source 2 and the original 4, as interrupting the light from the light source 2 opposite to the original 4 surface, the photodetector 6 is irradiated directory with the light from the light source 2, and this direct light is read out by the photodetector 6, and the correction of the picture information is executed. Thus, without using a reference member to be the reference of a picture information correction, the uniform density can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a document reading device in, for example, a facsimile machine, and particularly to uniformity of reading density during image information correction.

[Prior Art] As shown in FIG. 4, a document reading device such as a facsimile machine irradiates light onto a document 4 on a contact glass 3 from a light source 2, which is an LED or a fluorescent lamp, installed in a metal housing 1. The reflected light passes through a lens array 5 and is imaged onto a plurality of light receiving elements 6 arranged in an array on a substrate, thereby reading the images of the characters 9 on the original document 4.

In such an image reading device, the amount of light from the light source 2 that illuminates the original 4 varies depending on the light emitting position, and there are variations in the output between the light receiving elements 6, so shading correction etc. are performed to eliminate these variations. is being carried out.

Conventionally, when performing this correction, for example, Japanese Patent Application Laid-Open No. 1-300
As shown in Japanese Patent No. 760, light is irradiated from a light source 2 onto the surface of a reference white board, a white document conveyance roller, etc., the reflected light is read by a light receiving element 6, and the signal is memorized. The image information is corrected based on the information obtained.

[Problems to be Solved by the Invention] In the above-mentioned conventional image correction, the white plate and the white document conveyance roller, which serve as the reference for image information correction, may be scratched,
Or, dirt and dust may adhere to it after long-term use.

In such a case, even if the light source 2 illuminates the white plate or the white document transport roller with uniform light, the amount of reflected light will decrease, making it impossible to correctly perform image information correction such as shading correction. , This has the disadvantage that the density of the read image becomes non-uniform.

The present invention has been made in order to solve these shortcomings, and an object of the present invention is to provide a document reading device that can obtain read images of uniform density without using a reference member that serves as a reference for image information correction. It is something to do.

[Means to solve the problem]

A document reading device according to the present invention reads characters on a document.

A light source that emits light for reading images is arranged so that it illuminates both the document surface and the light-receiving element surface, and when reading the document, the light from the light source is blocked from the light-receiving element surface, and when correcting image information, the light source is placed against the document surface. The present invention is characterized in that an optical path blocking movable body is arranged around the light source to block light from the light source and irradiate the light receiving element with direct light from the light source.

[Effect]

In this invention, the light source is arranged so as to illuminate both the document surface and the light-receiving element surface, and when reading the document, the light path blocking movable body is rotated between the light source and the light-receiving element to block light from reaching the light-receiving element. Read the manuscript.

Further, when correcting image information, the optical path blocking movable body is rotated between the light source and the document, and the light is directly irradiated from the light source to the light receiving element while blocking the light from the light source to the surface of the document. This direct light is read by a light receiving element and image information is corrected.

〔Example〕

FIG. 1 is a sectional view showing an embodiment of the present invention. As shown in the figure, a light source 2 made of, for example, a fluorescent lamp installed in a metal housing 1 irradiates light onto a document 4 on a contact glass 3, and at the same time a plurality of light receiving elements arranged in an array on a substrate. 6 is also placed in a position where light can be irradiated.

In the optical path of this light source 2, as shown in the perspective view of FIG.
A support portion 7a is supported coaxially with the light source 2, and an optical path blocking movable body 7 is provided which rotates around the light source 2 when reading a document and correcting image information.

When the document reading device configured as described above reads the document 4, as shown in FIG. The light incident on the document 4 is blocked, and the light from the light source 2 is irradiated only in the direction of the document 4. and,
The reflected light of the light irradiated on the original 4 passes through the lens array 5 and forms an image on the light receiving element 6 to read the image of the characters 9 on the original 4. In contrast, when correcting the image information, the third As shown in the cross-sectional view of the figure, the optical path blocking movable body 7 is rotated between the light source 2 and the document 4, and blocks the light that enters the document 2 from the light source 2. The light from the light source 2 directly illuminates the entire surface of the light receiving element 6.

When the light receiving element 6 receives direct light from the light source 2, it reads the direct light, stores the information, and performs image information correction such as shading correction.

〔Effect of the invention〕

As explained above, in this invention, a light source is arranged so as to illuminate both the document surface and the light receiving element surface, and when reading the document, the optical path blocking movable body is rotated between the light source and the light receiving element, so that the light beams directed to the light receiving element are rotated. When correcting image information, the movable light path blocking member is rotated between the light source and the document to block the light from the light source to the document surface, while directly irradiating light from the light source to the light receiving element. However, since this direct light is read by a light-receiving element and the image information is corrected, there is no need for a reference surface such as a white board or a white original transport roller that serves as a reference for correcting the image information. Information can be corrected.

In addition, since image information can be corrected without the need for a reference surface, image correction can be performed without being affected by scratches or dirt on the reference surface, and uniform density reading can be performed. .

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of the present invention, Fig. 2 is a perspective view showing a movable body for blocking the optical path, Fig. 3 is a sectional view showing the operation of the above embodiment, and Fig. 4 shows a conventional example. FIG. 2: light source, 4: original, 5: lens array, 6: light receiving element, 7: movable body for blocking optical path.

Claims (1)

[Scope of Claim] A document reading device including a light source that illuminates a document, light receiving elements arranged in an array, and a lens array that forms an image of reflected light from the document on the light receiving device, comprising: It is arranged so that both the surface and the light-receiving element surface are illuminated, and when reading a document, the light from the light source is blocked from the light-receiving element surface, and when correcting image information, the light from the light source is blocked from the document surface, and the light from the light source is directly illuminated. A document reading device characterized in that an optical path blocking movable body for irradiating light onto a light receiving element is arranged around a light source.