JPH02109463A - Picture reader - Google Patents

Abstract

PURPOSE:To attain the detection of a border of an original by providing a shield means moving a white reference plate from an irradiated position at the time of irradiating an original or shielding a irradiated position of the white reference plate. CONSTITUTION:When a read button of an operation section is depressed while an original P is set, a light source 2 is lighted and the presence of the original P is discriminated by a sensing means 6. When a read instruction is placed from the control section to a line image sensor 5, a white reference plate 7 is irradiated with the light source 2 to record a shading waveform and the reading state to able to discriminate the border of the original P is reached. Then a solenoid 12 is energized to attract the black plate 10 in a direction of the arrow (a) to move the white reference plate 7 and the carrying of the original P is started and the original P is irradiated with the light source 2 to read the original by the line image sensor 5.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a see-through type image identification mounting device δ.

(Prior art) Conventionally, this type of image reading device first illuminates a white reference plate placed above the original glass with a light source to perform shading correction, and then illuminates the original and uses the reflected light as a line. It is detected by an image sensor and the image is read.

(Problem to be Solved by the Invention) However, since the two-line image sensor cannot accurately detect the boundaries of the document, it has not been possible to perform trimming processing on the document image.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and it is an object of the present invention to provide a sheet-through type image reading device that is capable of detecting the boundaries of a document using a line image sensor and trimming the document image.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a light source that irradiates an original, an original transport means that transports the original in a direction intersecting the longitudinal direction of the light source, and a In an image reading device that has means for forming an image of light on a line image sensor through an optical system and converting image information into an electrical signal, and that irradiates a document after irradiating a white reference plate and performing shading correction. , the white reference plate is moved from the irradiation position during irradiation of the document, or a shielding means is provided for blocking the irradiated area of the white reference plate.

(Function) The function of the present invention based on the above configuration is that the white reference plate is first irradiated with light from the light source to perform shading correction, and when the original is irradiated, the white reference plate is in a non-irradiated state, and after the original irradiation is completed, the white reference plate is in a non-irradiated state. Return to initial state.

(Example) Next, the present invention will be described based on an example shown in the accompanying drawings.

FIG. 1 shows a first embodiment of the present invention, in which reference numeral 1 denotes an image reading device of the present application, 2 a light source for illuminating a document P conveyed by a conveying means (not shown), 3 a reflecting mirror, and 4 a lens. Reference numeral 5 denotes a line image sensor that converts reflected light irradiated onto the original P into an electrical signal. 6 is a detection means for detecting the leading end φ and the trailing end of the MmP being transported.

7 is a white reference plate provided above the Fjc draft glass 8.

Reference numeral 9 denotes a shielding means provided on the lower surface of the white reference plate 7, and the shielding means 9 is for shielding the irradiated area of the white reference plate 7 during irradiation of the document. This MM means 9 includes a black plate IO, a tension spring 11 that holds the black plate IO at the solid line position, and a black plate 1
The solenoid 12 moves the 0 to the position indicated by the chain double-dashed line against the tension spring 1. The second UA is a block diagram showing these configurations.

Next, the operation of the first actual y/AN will be explained based on the flowchart shown in FIG.

First, with the document P set, press the read button (
(not shown) (step ■), light source 2 lights up (
After the detection means 6 detects the presence or absence of the original MP by 14 NIJ steps, the control section issues a reading command to the line image sensor 5 (step ■), and the light M2 is transmitted to the white reference plate 7. is irradiated to record the shading waveform (step
)do.

Then, the solenoid 12 is turned on, the black plate lO is pulled in the direction of arrow a, the white Ti quasi-plate is moved to the position indicated by the two-dot chain line, and the conveyance of the original P (step q) is started, and the light source 2 is turned on. The document P is irradiated and the document is read by the line image sensor 5 (step history)), and after the document reading is completed, the detection means 6 detects the trailing edge of the document P (step (φ)) The solenoid 12 is activated. It is turned OFF and pulled in the direction indicated by the arrow by the tension spring 11 to return to the initial position indicated by the solid line (step groaning).

FIG. 4 shows a second embodiment of the present invention.

In the case of this second embodiment, the white reference plate 7 is at the position indicated by the solid line during shading waveform recording, and when the detection means 6 detects the leading edge of the document P, the solenoid 12 is turned on and the white reference plate 7 is pulled in the direction of arrow C. The two points move to position n of the 113th line. After the reading is completed, the detection means 6 detects the rear end of the original P and the solenoid 12 is turned off, and the white reference plate 7 is pulled in the direction of arrow d by the tension spring 11 and returns to the initial position. The other configurations are the same as in the first embodiment.

FIG. 5 shows a third embodiment of the invention.

This third embodiment shows an example in which a white reference plate 7, a slide/id 12, and a tension spring 11 are provided on the lower surface side of the document glass 8, and is configured to operate in exactly the same manner as the second embodiment. ing.

FIG. 6 shows a fourth embodiment of the invention.

In the figure, reference numeral 13 denotes a liquid crystal shutter provided on the lower surface of the white reference plate 7.
When the leading edge of the original P is detected, it enters the "closed" state and the document is read by cutting off the light source 2 and the white reference plate 7. After the original reading is completed, when the detection means 6 detects the trailing edge of the original P, the " 13
The system returns to the 1I'' state and waits for the next shading recording.Other configurations are the same as in the other embodiments.

FIG. 7 shows a fifth embodiment of the invention.

In the figure, 14 is a plate member, and the plate member 14 has front and back surfaces formed by a white base board 7 and a black board 10, and
It is rotatably supported by a rotating shaft 15 that is orthogonal to the conveyance direction of the document P. The rotating shaft 15 is configured to rotate 1000 times in the direction of an arrow (or in the opposite direction) by a driving means (not shown) such as a stenting motor.

That is, when reading the shading waveform, the white substrate 7 is located on the F side as shown in the figure, and the detection means 6 is located on the side of the original P.
When the leading edge of the document is detected, the driving means is driven and rotates 1000 times to position the black plate 10 on the lower surface side and read the document. Then, when the detection stage 6 detects the trailing edge of the original P after the original reading is completed, the driving means is driven again and the 100
It rotates to 0 and the white reference plate 7 is on the bottom side, which is the initial state! Return to E.

(Effects of the Invention) According to the present invention, image signals of the original can be used, which was previously possible only in flat-bed image reading devices that read images by moving the reading position of the image line sensor in a direction intersecting the line sensor. Boundary detection has become possible even in sheet-through type image reading devices, and accurate position detection of a document and trimming processing of a document image have become possible also in sheet-through type image reading devices.

[Brief explanation of the drawing]

The figures show embodiments of the present invention, in which Fig. 1 is a schematic explanatory diagram of the first embodiment, Fig. 2 is a block diagram thereof, Fig. 3 is a flowchart thereof, and Figs. FIG. 6 is a schematic explanatory diagram of second, third, fourth, and fifth embodiments. Explanation of symbols 1... Image reading device of the present invention 2... Light source 5... Line image sensor 7... White reference plate 9... Shielding means P...
・Manuscript+ij,', Figure 1, Figure 3

Claims (1)

[Claims] A light source that irradiates an original, an original transport means that transports the original in a direction intersecting the longitudinal direction of the light source, and a light reflected from the original that is focused onto a line image sensor via an optical system. In an image reading device that irradiates a document after performing shading correction by irradiating a white reference plate, the white reference plate is moved from an irradiation position during irradiation of the document. 1. An image reading device comprising a shielding means for shielding an irradiated portion of a white reference plate.