JP2687407B2 - Manual scanning image scanner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to the fields of information processing, image processing, etc.
More specifically, it relates to an image scanner.

[Prior Art] Conventionally, a manual scanning type image scanner has been proposed and put into practical use as a small and low-priced image scanner.
In many cases, an LED array is used as a light source, a document image is formed on a line image sensor by a lens, and an image is read by manually moving the entire image scanner in the sub-scanning direction. FIG. 2 is a sectional view of a conventional general manual scanning type image scanner. A light source 2, a reflecting mirror 3, a lens 4, an image sensor 5, and an image sensor substrate 6 are arranged and fixed in the case 1 as shown in the figure. An LED array, a fluorescent lamp, or the like can be used as the light source. An original window 7 is opened in the case, and a transparent plate 8 is installed on the upper surface. Each of these has an appropriate length in the direction perpendicular to the drawing. This direction is the main scanning direction. The original 9 is illuminated by the light source 2, and the optical path 10 is bent by the reflecting plate 3 as shown in the figure, and reaches the image sensor 5 through the original window 7, the reflecting plate 3 and the lens 4.

Sub-scanning can be performed by moving the entire image scanner on the original 9 in the arrow direction. At that time, the roller 11 rotates, and the rotation is detected by an appropriate detector (not shown) to synchronize the main scanning and the sub-scanning.

[Problems to be Solved by the Invention] In these scanners, a problem generally called shading occurs. The causes of shading include variations in the light intensity distribution of the light source, peripheral dimming of the lens, and bit variations in the image sensor. The shading by the light source or the lens can be corrected to some extent by the shading correction plate, but the bit variation of the image sensor cannot be corrected.

Although a color image scanner can be realized by using a color image sensor, accurate color reproduction is required in the color image scanner, and white balance must be taken for that purpose.

In order to perform shading correction including bit variation and white balance adjustment, a method of reading a white reference document having uniform density and normalizing an image signal using the signal as a reference signal is generally used. .

However, in the manual scanning type image scanner, since the optical path is fixed with respect to the image scanner, only the original surface can be read and a white reference original cannot be prepared in the image scanner. It is possible to prepare a white reference document separately from the image scanner and then read the white reference document before each reading, but the operation is complicated, and the white reference document is not damaged or lost. There is a high possibility that problems will occur and it is not practical.

[Means for Solving the Problems] In order to solve the above problems, in the present invention, a white reference original is prepared and the reflecting mirror in the middle of the optical path is rotatable.

[Operation] The reflecting mirror is always set so that the optical path is on the white reference original, and the optical path is set on the reading original by rotating the reflecting mirror by a small angle.

[Examples] The present invention will be described according to specific examples. FIG. 1 is a sectional view of a manual image scanner according to an embodiment of the present invention. The basic configuration is the same as that of the conventional manual scanning type image scanner, but it is different in that the reflecting mirror is rotatable and that a white reference document is installed. The reflecting mirror 3 is integrally held by the reflecting mirror holding member 12 and is rotatable around a rotation center 13. Reflector holding member 13
One end thereof is connected to the tension spring 14 attached to the case 1, and the tension spring 14 constantly applies a rotational force in the clockwise direction in the figure. Reflector holding member 13
The other end of the is rotatably engaged with the link 15. The link 15 is freely rotatable around the link rotation center 16.
One end is in contact with the button 17. Normally, the tension spring 14 causes the reflector holding member 12 to rotate in the clockwise direction, and the link 15 engaged therewith to rotate in the counterclockwise direction. As a result, the button 17 is pressed upward.

In the vicinity of the document window 7 on the inner surface of the case 1, a white reference document 18 is attached. The reflecting mirror 3 is always installed at an angle such that the optical path is on the white reference document 18.

By pressing the button 17, the link 15 rotates clockwise, and the reflecting mirror holding member 12 and the reflecting mirror 3 engaging with the link 15 rotate counterclockwise by a slight angle. As a result, the optical path 10 moves as shown by the broken line in the figure and reaches the reading position on the original 9 through the original window 7. By providing the stopper 19 so that the rotation of the link 15 is restricted at such an angle, the button
By pressing 17, the optical path can always be positioned accurately at the reading position on the original.

As a specific method of using the present invention, for example, the white reference document 18 is read when the power of the image scanner is turned on, and the output signal of the image sensor 5 at that time is stored in a memory (not shown). When scanning a document, the button 17 is pressed so that the optical path 10 is located at the document reading position in the document window 7, and then the document 9 is read, and the output signal of the white reference document 18 is stored in advance. The shading correction can be performed by performing the normalization processing in comparison with. The reading range of the original 9, the reading start position, etc. can be easily confirmed through the transparent plate 8.

If a color image sensor is used as the image sensor 5, it may be possible to realize a manual scanning type image scanner capable of color reading. In this case, the white balance can be adjusted by reading the white reference document 18 for each separated color.

In addition, in the general manual scanning type image scanner,
There is a switch for switching the electric signal that informs the signal processing circuit that the document is being read, but if the button 17 in the present invention and this switch are linked,
The user can perform these corrections and adjustments without particularly consciously performing operations for shading correction or white balance adjustment.

Here, a link mechanism is proposed as a rotating mechanism for the reflecting mirror holding member 12, but other mechanisms are conceivable, of course, and the mechanism is not limited.

[Effects of the Invention] According to the present invention, by adding a simple mechanism and member, it is possible to realize a manual scanning type image scanner capable of shading correction or white balance adjustment without impairing document visibility.

[Brief description of the drawings]

FIG. 1 is a sectional view of a manual scanning type image scanner according to an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional general manual scanning type image scanner. 1 ... Case, 2 ... Light source, 3 ... Reflector, 4 ... Lens, 5 ... Image sensor, 6 ... Image sensor substrate, 7 ... Original window, 8 ... Transparent plate, 9 ... Original ,Ten……
Optical path, 11 …… Roller, 12 …… Reflecting mirror holding member, 13 …… Rotation center, 14 …… Tension spring, 15 …… Link, 16 …… Link rotation center, 17 …… Button, 18 …… White reference document , 19 ...
… Stopper

Claims (3)

(57) [Claims] 1. A light which reflects light from a light source on a surface to be read, converts the reflected light into an optical path in the direction of an image forming lens by an optical path changing mirror, and the image forming lens contains information on the surface to be read. In an image scanner that forms an image on a line image sensor and manually scans the surface to be read, the optical path conversion mirror is rotatably provided about an axis orthogonal to the scanning direction, and the optical path conversion mirror is A manual scanning type image scanner, which is normally urged to read a reference plate provided inside the image scanner. 2. The optical path changing mirror is rotated so as to form a light containing information on the surface to be read on the line image sensor by pressing a read button. Manual scanning image scanner. 3. The manual scanning type image scanner according to claim 2, wherein the reading button is linked with a switch for outputting an electric signal for starting reading.