JPH01149571A - Image reader - Google Patents

Abstract

PURPOSE:To read the same information of an original without using a storage circuit for synchronizing reading information, etc., to simplify an optical system, to reduce an energy consumption for illuminating, and to reduce cost by providing a mirror unit to have plural reflecting surfaces. CONSTITUTION:A mirror unit 5 is composed by fitting three mirrors 5R, 5G and 5B at prescribed angles to a first mirror base unit U1. At the time of reading the color image of an original 2 on a original platen 1, an illuminating lamp 4 is lighted up, the unit U1 having the lamp 4 and unit 5 scans in an arrow A direction at a velocity (v), and a second mirror base unit U2 having mirrors 6 and 7 scans in the same direction at a velocity v/2. In such a case, a light beam from a straight line including an reading point O of the original 2 and to be made orthogonal in a scanning direction is refracted in different directions by the mirrors 5R, 5G and 5B, thereafter, refracted by the mirrors 6 and 7, and image-formed through an image-forming lens 8 to line sensors 9a, 9b and 9c. Thus, the same information of the original 2 can be simultaneously read, a device can be simplified, and the cost can be reduced.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention scans the surface of the document and forms a light image thereof on a plurality of line sensors arranged in parallel in a synchronous direction, thereby creating a color image of the document. The present invention relates to an image reading device.

(Prior Art) Conventionally, as a means for decomposing and calculating single image information such as a color image of a document, a system in which a plurality of line sensors such as CCDs are arranged in a synchronous direction has been proposed.

FIG. 6(a) shows an example of this, in which the reading means lOO
has three line sensors 101, 102 and 103 arranged in parallel with a predetermined pitch PI, and each sensor 101, 102 and 103 has a red, green and blue filter 101R.

102G and 103B are attached. That is, in this reading means 100, color image light as single information is transmitted to each line sensor 101.

102.103, it is possible to sequentially separate the colors and output them as color signals.

FIG. 6(b) shows an image reading device that uses this reading means 100 to read a color image on a document. That is, in this apparatus, a mirror unit 105, 106 and a light source are used to illuminate the document 104 on which a color image is written with an illumination lamp, and scan the reflected image light in the direction of the arrow S at a speed ratio of 2:1. Via the image lens 107.

Each line sensor 101, 102, 103 of the reading means 100 is arranged to have a light receiving surface perpendicular to its optical axis.
A color image on the document 104 is read by forming an image on the document 104 and performing a predetermined calculation.

(Problem to be solved by the invention) By the way, in such a conventional example, each line sensor 1
01, 102, and 103 are provided at intervals of pitch P1, the reading lines B, G, and R on the document 104 read by each sensor 101, 102, and 103 are different. Therefore, when reading the same information on the reading line of the original 104 by color separation, for example, the information read first by the sensors ioi and 102 is delayed and output according to the pitch between the sensors, and each line sensor 101 .10
Since the information from 2 and 103 must be processed in a synchronized manner, a circuit such as a memory for storing this information is required, which causes a problem of increased costs.

Furthermore, if the magnification of the optical system is β1 (on the original side), the pitch between the sensors is Pl, so the reading lines on the original 104 are 2β1 for the reading lines R and B at both ends.
- Since they are separated by Pl, it is difficult to uniformly illuminate this wide range of reading lines R, G, and B with an illumination lamp.

In this case, in order to uniformly illuminate a wide range of areas, it is possible to place the illumination lamp away from the document surface, or to separate the illumination light for each color, but it is also possible to place the illumination lamp away from the document surface. This leads to an increase in the size of the optical system and a significant decrease in illumination efficiency, while splitting the illumination light also has the problem of causing a decrease in illumination efficiency and increasing power consumption.

Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and its purpose is to be able to read the same information on a document without using a memory circuit for synchronizing the read information. An object of the present invention is to provide an image reading device that can significantly reduce costs, simplify the optical system, and suppress power consumption for illumination.

(Means for Solving the Problems) In order to achieve the above object, in the present invention, an optical image of the original is formed on a plurality of linear reading means using an imaging lens, thereby forming an image of the original. In an image reading device that reads
A mirror unit having a plurality of reflective surfaces for respectively guiding optical images of the same portion of the document to the plurality of reading means is provided.

(Function) In the present invention having the above configuration, when the mirror unit is scanned, the optical image of the same part of the document is mirror unit/)
The light is reflected by a plurality of reflecting surfaces provided at the front and is simultaneously imaged on a plurality of linear reading means via an imaging lens.

Therefore, the reading means can obtain a plurality of pieces of information regarding the same image information.

In addition, since the structure is such that light images of the same part of the document are guided to the reading means, when illuminating the document when reading one image,
There is no need to uniformly illuminate a wide area.

(Example) The present invention will be explained below based on illustrated embodiments.

1 to 3 show an embodiment of an image reading device according to the present invention. FIG. 2 shows the overall configuration of the same embodiment, in which 1 is a document table made of glass or the like;
Place. Reference numeral 3 denotes a document holder for fixing the document 2 placed on the document table l.

4 is a lamp for illuminating the original, and the reflected image light of the original 2 illuminated by this lamp 4 is reflected by a mirror unit 5.
An image is formed onto the CCD 9 via the mirror 6.7 and the imaging lens 8. Here, the lamp 4 and the mirror unit 5 are attached to the first mirror unit (U+), and the mirrors 6.7, which form an angle of 90 degrees to each other, are attached to the second mirror unit (U2), and both mirrors 22) U+
.

U2 is scanned in the direction of the arrow at a speed ratio of 2:l based on the principle of a movable pulley. Note that 10 is a cooling fan for cooling the inside of the apparatus.

FIG. 3 shows the CCD 9 used in this example,
Line sensors 9a and 9b as reading means have 5000 effective pixels, each pixel of 10 pm x 10 gm being arranged on a CCD chip 9A.

Three sensors 9C are arranged parallel to the synchronization direction at a distance of 1801Lm (18 lines), and the corresponding pixels of each sensor are aligned in a direction perpendicular to the synchronization direction. Each line sensor 9a.

9b and 9c are red, green, and blue filters 9R and 9G, respectively.
, 9B is attached, and it is an R sensor.

The line sensors 9a, 9b, and 9c, which serve as the G sensor and the B sensor, are driven independently and synchronously.

Figure 1 shows an enlarged schematic configuration of the main parts of the optical system of this embodiment.
The mirror unit 5 attached to + consists of three mirrors 5R, 5G, 5B, each mirror 5R, 5G, 5
B is attached to the first mirror stand unit U+ at a predetermined angle. That is, in the figure, when the mirrors 5R, 5G, and 5B are not provided, the imaging lens 8
Let R', G', and B' be the virtual image points of the respective sensors 9a, 9b, and 9c that are imaged by R'.
, G', , line segment OR' connecting B' and reading point 0,
Perpendicular bisectors of OG', OB' Nl, N2,
Each mirror 5R in the plane containing N3.

5G and 5B reflective surfaces are arranged.

In the above configuration, when reading the color image on the document z placed on the document table 1, the illumination lamp 4 is turned on and the first mirror table 22 having the lamp 4 and the mirror unit 5 is turned on. t) Scan U+ in the direction of arrow A at a speed of V, and at the same time scan the second mirror stand unit having a mirror 6°7 in the same direction at a speed of m/2.6 Then, the image light reflected by the two sides of the original Among the light beams, the light beams from a straight line including reading point 0 on the second side of the original and perpendicular to the scanning direction are transmitted to the mirrors 5R and 5G provided on the first mirror stand unit (U+).
, 5B in different directions, and then reflected by the mirror 6.7 provided on the second mirror stand unit (U2) to enter the imaging lens 8, and then onto the corresponding line sensors 9a, 9b, 9c. images are formed at the same time.

Red is on each line sensor 9a, 9b, 9c.

Since green and blue filters 9R, 9G, and 9B are provided, image signals corresponding to the same image information on the two sides of the document are color-separated and output simultaneously from each line sensor 9a, 9b, and 9c. Then, the color image on the original 2 is read by encoding the image signals output from the respective sensors 9a, 9b, and 9c, and performing arithmetic processing such as level correction and masking correction by a control circuit (not shown).

In the optical system of this embodiment, the imaging magnification of the imaging lens 8 is β (document side, lβ1≧1), the brightness is F, the focal length is f (m layer), and the synchronization direction of the parallel line sensors is When the number of arrays is n (numbers) (=3) and the interval between the sensors is P (layer m), the diameter of the light beam on the imaging lens 8 is given by f/F, and the virtual document surface reading width R'B ' is given by (n-1)βP. When the value (n-1)βP of the virtual document surface reading width R'B' exceeds twice the value f/F of the beam diameter, the mirror 5 expands in the height direction, which causes the device to On the other hand, if βP is smaller than 2■, it will be difficult to divide each luminous flux by the first mirror unit U+, so β(|β|≧1), F, f, P Take the value of

As described above, in this embodiment, the mirror unit (2) 5 attached to the first mirror stand unit Ul has three mirrors 5R and 5G installed at different angles.

5B, and each line sensor 9a, 9b has a color filter to detect information on the same portion of the document 2.

By focusing on the image 9C, the same information on the document 2 can be read at the same time. Therefore, the color image of the document 2 can be read without providing a circuit such as a memory for storing previously read information, and the apparatus can be simplified and costs can be significantly reduced.

In this case, the mirrors 5R, 5G, 5B, each of which has its reflective surface turned back by the second mirror stand unit (U2), are virtual imaging points R' by the imaging lens 8 of each line sensor 9a, 9b, 9c, G'.

Line segment OR' connecting B' and the same reading point 0 of document 2
, OG', OB' bisectors Nl, N2.

By arranging it so that it is located on N3, the reading point is 0.
The light beams from the line sensors 9a, 9b, and 9c are reflected by the mirrors 5R, 5G, and 5B, and are imaged on the line sensors 9a, 9b, and 9c via the mirrors 6.7 and the imaging lens 8 without being defocused. . As a result, each sensor 9a, 9b
, 9c are constant, and no color shift occurs during reading.

Also, the same information of the original 2 is simultaneously transmitted to each line sensor 9a,
By enabling reading with 9b and 9c, there is no need to uniformly illuminate two sides of the original over a wide range during reading, and therefore the original 2 can be illuminated efficiently, making the optical system larger. Furthermore, since the illumination light is not used separately for each color, the document 2 can be efficiently illuminated, and the power consumption of the lamp 4 can be suppressed.

In this embodiment, the mirror unit 5 attached to the first mirror stand unit U1 is made up of three mirror members 5R,
5G and 5B, but as shown in FIG.
20B is a mirror 5R constituting the mirror unit 5,
5G.

It may be configured to have the same nine angular positions as each reflective surface of 5B. In this case, there is an effect that adjustment of the optical system becomes easier.

Furthermore, although the color separation filters 9R, 9G, and 9B used in this embodiment are red, green, and blue filters, yellow, magenta, and cyan filters may also be used.

In addition, the locations where the filters are provided are each line sensor 9a,
It is not limited to the surfaces 9b and 9c, and may be arranged near the first mirror unit.

Further, although this embodiment has a configuration in which a color image is separated into three colors and read, it is also applicable to an apparatus that recognizes a specific color using a two-tree line sensor.

Furthermore, in this embodiment, as shown in FIG. 3, the corresponding pixels of each line sensor 9a, 9b, 9c are aligned in the direction orthogonal to the synchronization direction, but for example, as shown in FIG. , by shifting the pitch by 1/n of the length d of each pixel of n line sensors 30, 31 and calculating simultaneously each line sensor 30, 31, it is possible to increase the apparent resolution of the device by n times. can. By the way, for rabbit 1 shown in Figure 5, since n=2, the resolution is doubled.

Furthermore, if a filter is arranged so as to guide the blue light flux with low reading sensitivity to the side where the light distribution characteristic at the point where the document 2 is irradiated is the largest, each line sensor 9a
, 9b, and 9c becomes smaller, and the balance between them is improved.

(Effects of the Invention) In the present invention having the above-described configuration and operation, a mirror unit having a plurality of reflective surfaces for respectively guiding optical images of the same portion of a document to a plurality of linear reading means is provided. This allows the same information on a document to be read simultaneously through multiple reading means, making it possible to read the color image of a document without the need for a memory or other circuit to store the information once read. becomes. As a result.

This has the effect of simplifying the device and significantly reducing costs.

In addition, by making it possible to read the same information on a document at the same time, there is no need to uniformly illuminate a wide area of the document surface during reading, making it possible to illuminate the document efficiently and increasing the size of the optical system. You can reduce costs without having to do anything. Furthermore, since the illumination light is not divided and used for each color, the document can be efficiently illuminated, and the power consumption of the illumination light source can be suppressed.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing image reading by an embodiment of the image reading device according to the present invention, FIG. 2 is a longitudinal cross-sectional view showing the overall configuration of the embodiment, and FIG. 3 is an illustration applied to the embodiment. FIG. 4 is a side view showing another example of the mirror unit; FIG. 5 is an explanatory view showing the arrangement of the line sensor to improve its resolution; FIG. 6(a) and 6(b) show a conventional image recording device, FIG. 6(a) is an enlarged front view showing the reading means, and FIG. 6(b) is a schematic configuration diagram of the main parts of the device. It is. Explanation of symbols 2...Original 5...Mirror unit 5
R, 5G, 5B...Mirror 8...Imaging lens 9...C0D9a, 9b
, 9c... Line sensor (reading means) Fig. 4 Fig. 5

Claims (7)

[Claims] (1) In an image reading device that reads an image of an original by focusing an optical image of the original onto a plurality of linear reading means using an imaging lens, an optical image of the same portion of the original is sent to the plurality of reading means. An image reading device comprising a mirror unit having a plurality of reflecting surfaces for guiding each image. (2) The mirror unit includes a first mirror unit that scans at a constant speed while maintaining a constant distance from the document, and a first mirror unit that scans at a speed of 1/2 of the first mirror unit and is guided by the first mirror unit. It consists of a second V-shaped mirror unit that guides the optical image of the original document to the imaging lens;
2. The image reading device according to claim 1, wherein a mirror unit is provided with the plurality of reflective surfaces. (3) The plurality of reflective surfaces of the first mirror unit correspond to virtual image formation points by the imaging lens of the reading means folded back by the reflection surface of the second mirror unit, and the same reading point on the document. 3. The image reading device according to claim 2, wherein the image reading device is located on a perpendicular bisector of a line segment connecting the two lines. (4) The image reading device according to any one of claims 1 to 3, characterized in that a color filter is provided in front of at least one reading device among the plurality of reading devices. (5) The image reading device according to claim 4, wherein the color filter is a color separation filter of red, green and blue, or yellow, magenta and cyan. (6) Corresponding pixels of the plurality of reading means are arranged so as to be shifted in the synchronization direction by 1/n pixels (n is the number of reading means), respectively. The image reading device according to any one of Item 5. (7) The number of the reading means and the number of reflective surfaces of the mirror unit are n, and the imaging magnification of the imaging lens is β (|β|≧
1), the brightness of the lens is F, the focal length of the lens is f
, when the interval in the synchronization direction of the reading means is P, |(n-1)βP/(f/F)|<2, and βP>2
2. The image reading device according to claim 1, wherein the values of n, β, F, f, and P are set so as to satisfy the relationship (mm).