JPH02277374A - Image reader - Google Patents

Abstract

PURPOSE:To read a color image at high speed by reading the image of a read original synchronizing with the rotation of a cylindrical drum on which plural lengthy color filters for color separation are provided in a axial direction at prescribed intervals. CONSTITUTION:When the reading of the image is performed, a light source 2 is lit by inputting a driving power source, and light transmits the color filter 11, 12, or 13, and transmits the read original passing an aperture 4a, and is converged at an image-forming optical system 6, and is image-formed on a linear image sensor 7. Also, the drum 1 is rotated by the start-up of a stepping motor 3 via a timing belt 32, and the color filters 11, 12, and 13 confronting with the aperture 4a are switched sequentially. When a slit 14a is detected first by a senser 16 when starting up, all the positions of the color filters 11, 12, and 13, the rotating state of the drum 1, and the read timing of the linear image sensor 7, etc., are controlled by the number of pulses inputted to the stepping motor 3 hereafter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image reading device for reading color images, and particularly to a color separation device thereof.

[Prior Art] As one of the color separation devices in a conventional color image reading device, a light source uses red R, green G, and blue B.
Using three fluorescent tubes, the three fluorescent tubes are blinked sequentially for each reading line to sequentially irradiate R9G and 83 colors of light, which are then read as image data by a photosensor via an imaging optical system. There is something. Also, for example, JP-A-60-2063
In the device disclosed in Publication No. 61, a drum for color separation is arranged so as to surround a photosensor, a circuit board, and two integrated circuit elements connected to this circuit board, and a document is placed outside of this drum. Light sources are provided at predetermined intervals via the

[Issue to be solved] In the first conventional device described above, R and G light sources are used.

Since three fluorescent tubes in B are used, a light source switching circuit is required for multiple light sources, and since the fluorescent tubes are blinked at high speed, measures must be taken to deal with the rise characteristics of the fluorescent tubes.
The equipment inevitably becomes larger and the number of parts increases. Further, in the second conventional apparatus, only one light source is required, but the drum for color separation has a large diameter and requires a large space. Furthermore, the large diameter of the drum makes it difficult to rotate at high speed, making it unsuitable for high-speed reading.

Therefore, the first objective of the present invention is to reduce the number of parts, simplify the configuration, reduce size and cost, and
The purpose is to make it possible to read color images at high speed.

Another object of the invention is fading of color filters.

The purpose is to prevent decolorization as much as possible and to enable accurate reading of color images over a long period of time.

[Means for Solving the Problems] In order to achieve the above object, an image reading device of the present invention includes a cylindrical drum in which a plurality of color separation color filters elongated in the axial direction are provided at predetermined intervals; A driving means for rotationally driving this drum, a light source disposed in the hollow part of the drum, and a light source arranged in a hollow part of the drum face each other at a predetermined interval with the drum and the document to be read in between. The scanner is equipped with a linear image sensor that reads the document, and a sub-scanning device that moves the document to be read.

In addition, in order to prevent color fading and bleaching of the color film, the image reading device of the present invention locates the light source in a cylindrical shielding body having an elongated opening in the axial direction, and this opening connects to the linear image sensor. I try to face it. Furthermore, a shielding plate is provided which can open and close the above-mentioned opening.

[Example] The present invention will be explained in detail below.

FIG. 1 shows a schematic configuration of the present invention. As is clear from this figure, a fluorescent tube 2 serving as a light source is installed in the hollow part of a drum 1 having color filters for color separation, which will be described later. 4 is provided above. A document table 5 for the document F to be read is provided below the mounting table 4 so as to be movable in the direction shown by arrow a (sub-scanning direction). , an imaging optical system 6 such as a SELFOC lens array, and a linear image sensor 7 are opposed to the drum 1. The reading direction of the linear image sensor 7 is set to match the axial direction of the drum 1 and the light source 2. A sub-scanning means 8 for moving the document table 5 in a sub-scanning direction perpendicular to the main-scanning direction is composed of a drive motor, a timing belt reduction mechanism, a pulley, and a drive wire rope.

As shown enlarged in FIG. 2, the drum 1 has a cylindrical shape, and has a large number of axially elongated slits 1a formed at predetermined intervals in the circumferential direction. 1a is a light shielding portion 1b for preventing color mixture. A step is provided on the inner wall of the slit 1a, and this step allows the red R filter 11, green G filter 12, blue B filter 13, etc. In order, drum 1
It is installed so that it will not fall off due to wind pressure or centrifugal force caused by rotation. The length of the slit 1a is determined in relation to the optical system 6 and corresponds to the width of the document F to be read. Further, the inner and outer surfaces of the drum 1 are coated with a matte black coating to prevent diffused reflection and the influence of external light. At one end of the drum 1 (left end # in Figure 3), there is a detection disc 14.
is attached between the sleeve 15 and the sleeve 15. A slit 14a for detecting the start position is provided on the outer periphery of the detection disc 14, as shown in the second figure. A sensor 16 for detecting this slit 14a is attached to the mounting base 4. A sleeve 1 is attached to the other end of the drum 1 as shown in the second figure.
7 are connected to each other, and a timing gear 18 is fitted and fixed to this sleeve 17.

As shown in Figure 3.4, both ends of the fluorescent tube 2 disposed in the hollow part of the drum 1 are provided with grooves 2]a.

A holder 21.22 with 22a is fitted.

Lead wires 2a connected to the electrodes at both ends of the fluorescent tube 2,
2b pulls out one lead wire 2b from the split groove 22a to the outside, guides the outer peripheral surface of the fluorescent tube 2 in the axial direction to the other end, passes through the holder 21 from the split groove 21a, and is insulated from the lead wire 2a. They are pulled together and pulled out to the outside. The holder 21 is fixed to a mounting plate 23, and this mounting (=
The J plate 23 is removably attached to a receiving part 24 provided upright on the mounting base 4 with screws 25.The holder 22 is attached to a receiving plate 26 fixed to the mounting base 4. Support shaft 27
It is installed through. Further, a sliding bearing 28 is interposed between the sleeve 15 and the receiving part 24, and a bearing 29 is interposed between the sleeve 17 and the support shaft 27, and the drum 1 is rotatably supported on the mounting base 4. ing.

As shown in FIG. 5, a timing gear 31 is fixed to the shaft of the stepping motor 3, which is a driving means for the mounting base 41, and a timing gear 18 is fixed to the drum 1 side.
A timing belt 32 is hooked and rotated between.

As shown in Figure 2.3, the mount 4 is provided between the drum 1 and the optical system 6 (Figure 1) in the direction of the arrow in Figure 3 (main scanning direction) and along the length of the document reading width. An opening 4a is formed in the opening 4a. Also, on the document table 5, there are two parallel flat glasses 51.5.
A document F to be read is sandwiched between the two and set on a carrier 53, and the carrier 53 is conveyed in the sub-scanning direction a (perpendicular to the plane of the paper in FIG. 3) by the sub-scanning means 8 via a wire rope or the like. .

When reading an image, the light source 2 is turned on by inputting the drive power, the light passes through the color filter 11, 12, or 13, passes through the aperture 4a, passes through the document F to be read, and is focused by the imaging optical system 6. Linear image sensor 7
image on top. Further, when the stepping motor 3 is started, the drum 1 rotates via the timing belt 32, and the color filters 11, 12, and 13 facing the opening 4a are sequentially switched. First, when the sensor 16 detects the slit 14a at startup, the color filter 11,
The position of 12 and 13, the rotational state of the drum 1, the reading timing of the linear image sensor 7, etc. are all controlled by the number of input pulses to the stepping motor 3. That is, for each line of the image of the read document F, the light transmitted through the R, G, and B color filters 11, 12, and 13 is sequentially imaged on the linear image sensor 7, and color image data is sequentially read. The document table 5 is fed line by line, and the color image data is sequentially read in the same manner. In this way, the light source 2 remains lit while all the images of the read document F are completely read.

Note that in the reading operation, one line is read as R, G,
The method is not limited to the method of reading with the B color filter and moving the original platen 5 one line, but also reading one side with the R color filter, then reading the first side with the G color filter, and then reading the B side.
It is also possible to read one side using a color filter and move the document table 5 three times.

When it becomes necessary to replace the light source 2, use the screws 25...
is removed to separate the mounting plate 23 from the receiving part 24, and the light source 2 is extracted from the holder 22 and replaced.

FIG. 6 shows another embodiment in which a means for preventing color fading and bleaching of the color filter is provided, in which a cylindrical shielding body 9 having an elongated opening 9a in the axial direction is provided, and the light source 2 is It is located within this shielding cylinder 9. The opening 9a is set to face the linear image sensor 7 (see FIG. 1).

The drum 100 has slits 100a for attaching R, G, and B color filters 11 to 13 similar to those described above, and light shielding portions 100b between them, as well as R, G filters.

A light shielding part 100C with a width sufficient to close the opening 4a of the mounting base 4 is provided between each set of color filters B.
・We have established

Fluorescent tubes usually do not reach the specified brightness immediately after they are turned on,
Since it is necessary to wait for 1 to 2 minutes, it is often left on at all times. In this case, light is constantly shining on a specific color filter, causing it to fade and fade.
May deteriorate.

In this embodiment, when the fluorescent tube is in a standby state with the fluorescent tube turned on, the light is shielded by the shielding cylinder 9, so that a specific color filter is not irradiated with light for a long time, and fading and deterioration can be prevented.

Furthermore, in FIG. 7, a shielding cylinder 91 having an opening 91a similar to that described above is provided, and a shielding plate 92 that can open and close this opening 91a is further provided. This shielding plate 92 moves concentrically with the shielding cylinder 91 to open the opening 91a as shown by the imaginary line when reading starts, and closes the opening 91a as shown by the solid line when waiting for reading. driven by means.

In the sixth and seventh figures, substantially the same parts as in the second figure are given the same reference numerals. Note that by making the shielding cylinders 9 and 91 from metal and electrically grounding them, the fluorescent tube 2
It is possible to reduce the discharge noise from the fluorescent tube 2, and it can also be used as a trigger electrode for the fluorescent tube 2. Further, by making the inner surfaces of the shielding cylinders 9 and 91 mirror-finished, the brightness from the openings 9a and 91a can be increased.

Note that the drum is not limited to a cylindrical shape, but can be modified as appropriate, such as a hexagonal column shape with a hexagonal cross section and two sets of color filters R, G, and B arranged therein.

Furthermore, it is also possible to form a color filter by making the drum into a transparent cylindrical shape and pasting a color filter on the outer periphery, or by forming a gelatin film and dyeing it with R2O, B dye.

Although the light source is shown as a rod-shaped fluorescent tube, it can be changed as appropriate, such as one in which light is guided from a separate lamp to the hollow part of the drum using an optical fiber.

[Effects] The image reading device of the present invention having the above configuration uses one light source and is kept lit until the end of image reading, so the number of parts is small, the configuration can be simplified, and costs can be reduced. Furthermore, the life of the light source can be extended.

Since only a light source is installed inside the drum for color separation,
It is possible to achieve miniaturization by having a small diameter configuration, and the color filters can be switched at high speed by driving the drum at high speed, so it is possible to read color images at high speed. Further, since a shielding cylinder and a shielding plate are provided to irradiate light only to the color filter at the reading position, fading and bleaching of the color filter can be prevented as much as possible, and accurate color images can be read over a long period of time.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram showing an embodiment of the present invention, Fig. 2 is an enlarged radial sectional view of the main part, Fig. 3 is an axial sectional view of the main part, and Fig. 4 is a part of the light source section. FIG. 5 is a partially cutaway perspective view, FIG. 6 is an enlarged radial sectional view of the main part showing another embodiment, and FIG. 7 is a main part showing still another embodiment. FIG. 3 is an enlarged radial cross-sectional view. 1.100...Drum, 11.12.13...Color filter for color separation, 2...
- Light source, 3... Drive means, 7... Linear image sensor, 8... Sub-scanning means, 9.91... Shielding cylinder, 9a, 91a - Φ opening, 92... Shielding plate, F...Reading manuscript. that's all

Claims (3)

[Claims] (1) A cylindrical drum in which a plurality of color separation color filters elongated in the axial direction are provided at predetermined intervals, a driving means for rotationally driving the drum, and a light source disposed in the hollow part of the drum. and a linear image sensor that faces the drum and the document to be read at a predetermined interval and reads an image of the document to be read through an imaging optical system in synchronization with the color filter, and moves the document to be read. An image reading device comprising a sub-scanning means. (2) The image reading device according to claim 1, wherein the light source is located in a cylindrical shielding body having an elongated opening in the axial direction, and the opening faces the linear image sensor. . (3) The image reading device according to claim 2, further comprising a shielding plate that can open and close the opening.