JPH01190167A - Picture reader - Google Patents

Abstract

PURPOSE:To prevent duplicated picture information or missing information by detecting the movement of an original and moving the image forming lens in the main scanning direction or main axis direction in response to the movement thereby revising the read effective picture element area of a solid-state image pickup element. CONSTITUTION:A radiated optical beam from a semiconductor laser 12 is stopped thin through a lighting lens 13 and irradiated on the surface of the original 1. Part of the light reflected and scattered is projected on a photodetection face 17 of the photodetector element 15 through an image forming lens 14 to form an image of a reflecting point D. When the original 1 is moved forward/reverse, the image of the reflecting point D formed by the lens 14 moves on the element 15. In this case, the element 15 detects at which position the point D is irradiated as on electric output, sends it to an arithmetic circuit to extract the movement x of the original 1 as the electric signal. Then the distance y from the duplicated part O1 to O2 of the original 1 is detected as the electric signal by the movement detection means. Then the movement means 16 controls the image lens 4 to be moved by yt in the main scanning direction S.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an image reading device that reads image information of a document using a solid-state image sensor.

PRIOR ART A conventional document transport type image reading device is disclosed in Japanese Patent Application Laid-open No. 54-
There is one disclosed in Japanese Patent No. 6713. That is, as shown in FIG. 7, while the original 1 is fed by the conveyance roller 2 and supported by the back positioning plate 3, the image information of the right half A and the left half B of the original 1 is transferred in the main scanning direction S.
The image is divided and reduced by the imaging lenses 4 and 5 provided in the image forming apparatus.

Image information of the document 1 is read by solid-state image sensors 6 and 7. In this case, the left and right reading areas 8 and 9 on the original document 1 do not move up and down, and
The relative positions and postures of the solid-state imaging devices 6 and 7 are precisely adjusted in advance so that they are continuous in a straight line without overlapping or separating at the connecting portion C.

However, in such a conventional image reading device, no matter how precise the adjustment may be in advance, if the document 1 lifts or moves during operation, duplicate images will be read at the connecting portion C. Therefore,
There is a problem that this leads to significant image deterioration and it is not possible to accurately read the image information of the document 1.

Next, such problems will be explained using specific examples. FIG. 6 shows a state in which the original 1 is displaced by ΔX (usually 0.2 to 0.5 mm) from the normal reading position P on the upper surface of the contact glass 10.

During normal normal reading, the document 1 is located at the reading position P, and the right half A of the image information is read by the solid-state image sensor 7 from 0° to ao, and from oo to b.
6, the left half B of the image information is read by the solid-state image sensor 6. However, the document 1 has now moved due to lifting etc. and is now at a position Q separated by ΔX from the normal reading position P.
Assume that it is located at At this time, the area from ○ to al is read by the solid-state image sensor 7, while the area from o2 to bl is read by the solid-state image sensor 6. As a result, the overlapped images from Q□ to 02 The area will be read as a portion of Δyll on the solid-state image sensor 6.

Next, the amount of movement ΔX of the original 1 and the solid-state image sensor 6 described above are calculated.
The relationship between Δyo which is read in duplicate above will be explained using specific numerical values as an example.

Now, assuming that the amount of document movement: Δx"0.5 mm, the imaging magnification: 1/m = 1/10, and the half angle of view of the image: θ = 20°, the area of Δy0 that is read overlappingly on the solid-state image sensor 6 is , Δyo=ΔX・(2tanθ/m)...(
1)=0.5・(2tan20°/10) #0.0364mm=36μm (2).

Therefore, from equation (2), the overlapped image area from ol to 02 of original 1 is 36μ on solid-state image sensor 6.
The data will be read over an area of m.

In addition to the conventional example described above, there is a similar one disclosed in the conventional example of Japanese Patent Application Laid-Open No. 59-52965, but the description thereof will be omitted here.

OBJECTS The present invention has been made in view of the above points, and an object of the present invention is to provide an image reading device that can accurately read image information of a document without duplication or omission.

Structure The first invention includes a movement amount detection means for detecting the amount of movement of the original from a reading position, and a movement means for displacing the imaging lens in accordance with the amount of movement of the original detected by the movement amount detection means. Therefore, the effective pixel area for reading of the solid-state image sensor is changed by displacing the imaging lens in the main scanning direction or the optical axis direction by the moving means in accordance with the amount of movement of the document detected by the movement amount detection means. This enables accurate reading by preventing duplication or omission of image information when reading a document.

The second invention includes a movement amount detection means for detecting the amount of movement of the document from the reading position on the first traveling body, and a second movement of the second traveling body by 172 of the movement amount of the document detected by the movement amount detection means. Since a moving means for displacing the two reflecting mirrors in the optical axis direction is provided, the optical path length can be changed by displacing the two reflecting mirrors by 1/2 of the amount of movement of the document detected by the movement amount detection means. The effective reading pixel area of the solid-state image sensor can be changed by correction, and thereby, duplication or omission of image information can be prevented when reading a document, and accurate reading can be performed.

An embodiment of the invention recited in claim 1 will be described based on FIGS. 1 to 3. Note that the same reference numerals are used for the same parts as in the prior art.

The movement amount detection means 11 includes a semiconductor laser 12 , an illumination lens 13 , an imaging lens 14 , and a photodetection element 15 . Further, the moving means 16 can displace the imaging lenses 4 and 5 in the main scanning direction S or in the optical axis direction T according to the moving amount ΔX of the original 1 detected by the moving amount detecting means 11. It has become.

In such a configuration, first, a method for determining the moving amount ΔX of the original 1 using the moving amount detecting means 11 will be described. As explained in the related art, it is assumed that the document 1 is at a position 11Q, which is moved by ΔX from the normal reading position P. At this time, the following processing is performed by the movement amount detection means 11.

The light beam emitted from the semiconductor laser 12 is narrowed through the illumination lens 13 and irradiated onto the surface of the original 1.

A part of the reflected and scattered light depending on the surface condition of the original 1 passes through the imaging lens 14 and passes through the light receiving surface 17 of the photodetector 15.
It is projected upward, creating an image of the reflected spot. And manuscript 1
moves in the front-back direction, the imaging lens 14 moves accordingly.
The image of the reflected spot created by the above also moves on the photodetector element 15.

At this time, the photodetecting element 15 detects the position irradiated by the reflection point as an electric force and transmits it to an arithmetic circuit (not shown). Due to this.

The amount of movement ΔX of the original 1 can be extracted as an electrical signal.

Next, a method for normal image reading by moving the imaging lens 4 using the moving means 16 based on the electric signal detected by the moving amount detecting means 11 will be explained. As for the direction in which the imaging lens 4 is moved, the first method is to move it in the main scanning direction S of the original 1, and the second method is to move it in the optical axis direction T perpendicular to the surface of the original 1. There is.

First, the first method will be explained based on FIG. 2. The movement amount detection means 11 detects the overlapping portion of the original 1 from O to O2.
The distance Δy is detected as an electrical signal Δy1. Then, the moving means 16 performs control as shown in the following equation.

Δys=Δy1・(1/(1+1/m))...(3)
However, m: imaging magnification, that is, the moving means 16 controls the imaging lens 4 to be displaced by Δys in the main scanning direction S.

Next, the second method will be explained based on FIG. In this case as well, the movement amount detection means 11 detects the movement amount ΔX of the original 1 from the position P as an electric signal Δy2.

Then, the moving means 16 performs control as shown in the following equation.

Δyt=Δy2・(1/(1+1/m))...(4)
However, m: imaging magnification, that is, the moving means 16 controls the imaging lenses 4.degree.

As a result, the area from 0□ to 02 is eliminated, and the area is divided into two at the minus point O1.

As described above, the movement amount ΔX of the original 1 is detected as the movement amount in the main scanning direction S or the movement amount in the optical axis direction T by the movement amount detection means 11, and the document 1 is moved in accordance with the movement amount. By displacing the imaging lenses 4 and 5 using the means 16, it is possible to read good image information without duplication or omission.

Next, an embodiment of the invention recited in claim 2 will be described based on FIGS. 4 and 5.

The first traveling body 18 includes a halogen lamp 19 as a light source.
, a reflecting mirror 20, and a movement amount detection means 11 are provided. Note that the movement amount detecting means 11 has been explained in the above-mentioned embodiment, so a description thereof will be omitted here.

The second traveling body 21 includes two reflecting mirrors 22. which are perpendicular to each other.
23 is provided on the optical path, and solid-state imaging devices 6 and 7 are provided on the optical path via imaging lenses 4 and 5. Further, this second traveling body 21 is provided with a moving means 24, and this moving means 24 moves by 172 of the moving amount ΔX of the document 1 detected by the moving amount detecting means 11. The two reflecting mirrors 22 and 23 can be displaced in the optical path direction R.

In such a configuration, it is assumed that the original 1 is now at a position Q moved by ΔX from the normal reading position P on the original table 25. First, the first traveling body 18 is moved to the location where the original 1 is set, and the image information of the original 1 is read. At this time, the movement amount detection means 11 reads the movement amount ΔX from the reading position [P of the original 1 as an electrical signal.

Then, based on the read electric signal, the moving means 24 displaces the two reflecting mirrors 22 and 23 of the second traveling body 21 in the optical path direction R by 1/2 of the moving amount ΔX.

As a result, the optical path length can be corrected, and the read image information is decomposed and reduced by the imaging lenses 4 and 5, and further detected by the solid-state image sensors 6 and 7, so that there is no overlap or omission. Good image information can be read.

In addition, in the case of the apparatus according to the present invention as described above, it is also effective for documents 1 whose surfaces are laminated in advance and which have a certain degree of thickness.

The invention having the first effect includes a movement amount detection means for detecting the amount of movement of the document from a reading position, and a movement means for displacing the imaging lens in accordance with the amount of movement of the document detected by the movement amount detection means. Therefore, the effective pixel area for reading of the solid-state image sensor is changed by displacing the imaging lens in the main scanning direction or the optical axis direction by the moving means in accordance with the amount of movement of the document detected by the movement amount detection means. This enables accurate reading by preventing duplication or omission of image information when reading a document.

The second invention includes a movement amount detection means for detecting the amount of movement of the document from the reading position on the first traveling body, and a second movement of the second traveling body by 172 of the movement amount of the document detected by the movement amount detection means. Since a moving means for displacing the two reflecting mirrors in the optical path direction is provided, the optical path length is corrected by displacing the two reflecting mirrors by 1/2 of the moving amount of the original detected by the moving amount detecting means. The effective reading pixel area of the solid-state image sensing device can be changed by changing the reading effective pixel area of the solid-state image sensing device, thereby making it possible to perform accurate reading by eliminating duplication or omission of image information when reading a document.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a movement amount detecting means section showing an embodiment of the first invention, FIGS. 2 and 3 are explanatory diagrams showing an image reading method thereof, and FIG. 4 is an embodiment of the second invention. FIG. 5 is a longitudinal sectional side view showing the overall configuration thereof, FIG. 6 is an explanatory view showing a conventional image reading method, and FIG. 7 is a perspective view showing a conventional example.

Claims (1)

[Claims] 1. Image information formed along the main scanning direction of a document fed by a conveyance roller and traveling is divided and reduced by an imaging lens to form a document image, and the formed document image is In an image reading device that reads image information of the original document by detecting the image information using a solid-state imaging device arranged in parallel with the imaging lens, a movement amount detection means that detects the amount of movement of the original document from a reading position; An image reading apparatus comprising: a moving means for displacing the imaging lens according to the moving amount of the document detected by the moving amount detecting means. 2. The image information of the document set at the reading position on the document table is reflected by the illumination optical system of the first traveling body, and the reflected image information is transmitted to two mutually perpendicular reflecting mirrors of the second traveling body. In the image reading device, the image reading device reads the image information of the document by reflecting the document and dividing and reducing it by an imaging lens to form a document image, and detecting the formed document image by a solid-state image pickup device. a moving amount detecting means for detecting the moving amount of the original from the reading position; and a moving amount detecting means for detecting the moving amount of the original from the reading position; An image reading device comprising a moving means for displacing a reflecting mirror in an optical path direction.