JPH09321956A - Filter changeover device in original reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the changeover device compact through a rotary drum filter where a prescribed changeover characteristic is ensured while suppressing the height of the filter changeover device as an original lighted sequentially and linearly is being read via the filter. SOLUTION: As for an image of an original being read via a rotary drum filter 10, a center of a rotary side plate 43 at both sides of the rotary drum filter 10 is supported turnably by a drive shaft 45, and the circumferential face of both the rotary side plates 43 are placed among a plurality of filter mount plates 47 adjacent to each other at an equal interval and connected in parallel with the rotary shaft 45 with a prescribed gap G and filters 48 are mounted to the filter mount plates 47 and an optical path L is formed through an opposite gap G with respect to a concerned filter 48.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter switching device in an original reading device used for making a plate from a printed original.

[0002]

2. Description of the Related Art For example, a document reading apparatus used for printing sets a document on a document table, moves the document table in a lateral direction, and linearly illuminates the document with a lens system. An image is formed on the line sensor through the line sensor, the line sensor is sequentially scanned to read an image signal, and the entire document is read by sub-scanning by moving the document table.

Various filters are switchably arranged in the middle of the optical path, and the original image is read in consideration of predetermined characteristics. As a mechanism for switching the plurality of filters, there is known a mechanism in which a filter is arranged like a windmill on the circumference of a rotating plate, and a desired filter is interposed in the optical path by controlling the rotation position thereof.

[0004]

However, in the switching mechanism of the wind turbine type filter as described above, the overall height of the rotary plate becomes large relative to the effective width of the filter, and the overall height of the document reading device becomes high. However, it has become an obstacle when it comes to downsizing and using the upper surface of the reading unit as a work desk space.

Specifically, in the above-mentioned document reading apparatus, since the document is attached / detached to / from the document table, the workability is required unless the work height is high to some extent. Is not preferable. On the other hand, in the reading unit, it is preferable to use it as a work desk space such as a work for setting the reading range of the document on the upper surface from the viewpoint of workability. In this case, the height of the upper surface of the reading unit is the original document. Depending on the size of the, it may not be possible to perform good work unless it is somewhat low.

That is, it is desired that the reading unit is provided so that the height above the portion where the document table moves is lowered, and the filter switching device described above is provided in this portion to secure a predetermined number of filters. However, it is required to be installed compactly. In addition, it is desirable that the size of the original that can be set is large, but it is not preferable to increase the size of the apparatus accordingly, and an increase in the original width leads to an increase in the aperture of the lens system and a filter width. Therefore, the filter switching device needs to be made compact.

Therefore, the present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a filter switching device in a document reading device that ensures a predetermined switching characteristic while suppressing the height of the filter switching device. is there.

[0008]

SUMMARY OF THE INVENTION A filter switching device of the present invention, which has solved the above-mentioned problems, is a line sensor that irradiates a document with linear light and reflects or transmits the reflected light through a rotary drum filter and a lens system. In an original reading device for reading an original image by forming an image on the upper surface of the rotary drum filter, the rotary drum filter rotatably supports the central portions of the rotary side plates on both sides by a rotary shaft, and the rotary side plates on both sides at the outer peripheral portion. A plurality of filter mounting plates connected in parallel with each other with a predetermined gap between adjacent filter mounting plates at equal intervals, and the filter is mounted on the filter mounting plate. On the other hand, the optical path is formed through a gap between the filter mounting plates on the opposite side.

Further, it is preferable to dispose the lens system in an eccentric position with respect to the rotary drum type filter so that the optical axis passes through a position deviated from the center of rotation of the rotary drum because the installation height can be further suppressed. Is.

[0010]

According to the document reading apparatus of the present invention as described above, a rotary drum type filter is adopted, and basically, a predetermined number of horizontally long filters can be installed, and the height thereof can be suppressed to be compact. Is obtained,
In particular, the desired filter mechanism can be obtained compactly by passing the optical path through the gap of the filter mounting plate and passing through the filter located in front of the lens system on the opposite side.

When the number of filters is an even number,
Since the optical path passes through a position deviated from the center of rotation of the rotating drum, it is not affected by the presence of an axis penetrating the center of rotation of the rotating drum, and the filter is tilted, which causes harmful reflected light. It is possible to prevent the generation of ghosts.

Further, when the optical path is set so as to pass through the eccentric position so as not to pass through the center of rotation of the rotary drum, the height above the optical path center of the filter switching device can be reduced in conformity with the support structure of the lens system and the like. As a whole, the height of the platen of the document reading apparatus as a whole and the height of the upper surface of the reading unit can be lowered to improve workability as a work desk space.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. 1 and 2 are a front view and a side view showing the overall configuration of the document reading apparatus. Note that the optical system portion is omitted in FIG.

The document reading device 1 includes a document setting section 2 in which a main body frame 4 constituting the framework of the device is formed low.
And a reading section 3 formed higher than the above, and the original setting section 2 has an original table 5 for detachably holding the original, and the original table 5 is slidably movable in the reading section 3 in the lateral direction. It is provided in. In addition, the reading unit 3
Has upper and lower reflective original document illumination fibers 6 and 7 for linearly illuminating the original document and a transparent original document illumination fiber 8, and a lens system 15 above the moving height of the original document.
A camera 9 having a line sensor 16 and a rotary drum filter 10 and a mirror portion 11 are provided in front of the camera 9, and a lamp box 12 and a substrate box 13 are provided below the camera 9.

On the other hand, the original table 5 has a movable base 23 slidably supported by two guide bars 21 and 22.
An original receiving member 24 made of a transparent material that is swingably mounted on the movable base 23 and has an original placed on its upper surface, and an original that is openably and closably attached to the movable base 23 and is closed while the original is pressed against the original receiving member 24. A document pressing lid 25 made of a transparent material is installed. This document holding cover 25 is a damper arm 26.
Is urged in the opening direction by.

The movable base 23 is supported by the above-mentioned guide bars 21 and 22 extending from the document setting section 2 to the reading section 3 on the main body frame 4 and is movable. The ball screw 27 extending from 2 to the reading unit 3 is screwed and linked, and the driving motor 28 rotationally drives the ball screw 27 to control the constant speed movement. The drive motor 28 is installed in the reading unit 3 and is linked to the end of the ball screw 27.

Although not shown, an opening / closing cover is installed on the upper surface of the document setting section 2, and the upper side is closed when the document table 5 is moved. Further, the document pressing lid 2
The closed state of 5 is locked by a lock mechanism, and the release mechanism of this lock is arranged on the body frame 4 side, and the document holding lid 25 can be opened and closed only when the document table 5 is stopped at a predetermined position. It is provided in.

On the other hand, the reading unit 3 has a pair of first and second pairs above the original table 5 which has moved as described above.
Reflective original document illumination fibers 6 and 7 are installed, and one transparent original document illumination fiber 8 is installed below to illuminate the original document linearly. Each of the fibers 6 to 8 is composed of a large number of optical fibers, the illumination end of which is linearly arranged in one row and held by a holder, and the other end of which is bundled into a cylindrical shape and placed under the reading unit 3 in a lamp box. It is installed facing 12 light sources (halogen lamps). Further, in front of the linear illumination end, the light flux is adjusted through the cylindrical rod-shaped lenses 31 to 33 and is irradiated onto the document. Three light sources are collectively arranged in the lamp box 12, and the inside of the lamp box 12 is cooled by a cooling fan.

The illuminating end of the first reflecting original illuminating fiber 6 is arranged so as to illuminate the surface of the original from an angle of 45 degrees diagonally forward of the original. The illuminating end of the second reflection original illuminating fiber 7 is installed horizontally from the front with respect to the original traveling direction, and a reflection mirror 34 obliquely installed obliquely downward is provided in the facing portion, and is oblique to the traveling direction. It is arranged so as to illuminate the surface of the original from 45 degrees behind. The transmission document illuminating fiber 8 has its illuminating end installed horizontally from the front to the traveling direction of the document, and a reflection mirror 35 inclined obliquely upward is provided at the facing portion to illuminate the document from below to above. To do.

A mirror portion 11 is provided above the illumination position of the document by the above-mentioned illumination fibers 6 to 8, and this mirror portion 11 is installed at the upper end corner of the main body frame 4 of the reading portion 3 and this mirror portion 11 is provided. The reflecting surface of the unit reflects the light from below in a direction substantially parallel to the direction of travel of the document, but instead of reflecting it at 90 degrees, the optical axis after reflection is relative to the horizontal direction (direction of travel of the document). It is set to incline slightly downward.

A rotary drum filter 10, a lens system 15 of a camera 9 and a line sensor 16 are installed in this order on the optical path L reflected by the mirror section 11, and these are fixed to a mounting frame 37. The frame 37 is obliquely fixed to the body frame 4. The mounting position of the camera 9 is adjustable.

In the camera 9, the lens system 15 is provided on the lens barrel, and the optical path L is divided at the focal position thereof via the half prism 39, and the line sensors 16 are alternately installed at the respective focal points so that signals on a straight line are generated. It is configured to be obtained continuously. Main scanning for sequentially reading the signals of the respective sensors in the line sensor 16 is performed by a control board (not shown), and the control board is installed in the board housing section 40 at the back of the camera, and between the camera 9 and the board housing section 40. Is provided with an adjustment space for absorbing variations in the focal length of the lens system 15, and the camera 9 is moved and adjusted in the optical axis direction.

The detailed structure of the rotary drum type filter 10 will be described with reference to FIGS. Flat plate-shaped support frames 41 are erected on both sides of the mounting frame 37, and the support frames 41 on both sides are connected by a connecting rod 41a extending in the lateral direction. The rotary drum 42 is rotatably supported by the support frame 41.

In the rotary drum 10, a laterally extending rotary shaft 45 is attached to a boss portion 44 fixed to the center of the outer surface of the disk-shaped rotary side plates 43 on both sides, and the rotary shaft 45 is attached to the support frame 41. Is pivoted to. Rotating side plates 43 on both sides
The outer peripheral portion of the rotary side plate 43 on both sides is parallel to the rotary shaft 45.
Filter mounting plates 4 (6 in the figure) for connecting
7 are attached at equal intervals. A predetermined gap G is formed between the adjacent filter mounting plates 47, and this gap G is provided in such a size that the optical path L reflected by the above-mentioned mirror portion 11 passes through.

A horizontally long rectangular filter mounting hole 47a is formed in the filter mounting plate 47, and each filter 48 having a predetermined color and density is mounted in the filter mounting hole 47a.

A gear-shaped belt pulley 51 is provided on a portion of one of the rotary shafts 45 that protrudes through the support frame 41, and a switching motor 52 mounted on the support frame 41 is provided with respect to the belt pulley 51. The toothed transmission belt 54 is hung from the driving belt pulley 53, and the rotary drum 42 is rotationally driven by the drive control of the switching motor 52. On the other side of the rotating side plate 43, a protruding reference plate 5 for detecting the origin position is provided on the outer surface.
5 is fixed, and a reference position sensor 56 is provided on the inner surface of the support frame 41 opposed to the reference position 5. The reference position sensor 56 detects the reference position of the rotary drum 42, and based on this, the desired filter 48 is positioned on the optical path L. Controls the rotational position.

FIG. 5 shows the arrangement of the filters 48 with respect to the rotary drum 42. Since the six (even) filters 48 are arranged at equal intervals, the filters 48 are arranged at symmetrical positions on the diameter passing through the rotation center 45. Is located in the optical path L
When the optical path L passes through the center of rotation 45, the optical path L passes through the two filters 48 on both sides. However, the optical path L is set at an eccentric position and the filter 4 stopped in front of the lens system 15 is moved.
8, the optical path L is formed through the gap G of the filter mounting plate 47 on the opposite side, and one inclined filter 48 is formed.
I try to pass only. The filter mounting plate 47
The angle may be changed so as to be orthogonal to the optical path L, but due to the inclination, it is possible to prevent the generation of a ghost due to harmful reflected light. Further, the rotary shafts 45 on both sides may be provided so as to penetrate the rotary drum 42.

Next, FIG. 6 shows an example of a rotary drum 42 'in which five (odd) filters 48 are installed. When filter mounting plates 47 are arranged at equal intervals, a straight line passing through the center of rotation 45 is formed. Even if the optical path L is set so as to pass through the rotation center 45 because only one filter 48 is located, the filter 48 located in front of the lens system 15 should pass through the gap G of the filter mounting plate 47. You can However, even in this case, as described above, the optical path L
May be set so as to pass through an eccentric position deviated from the rotation center 45 of the rotary drum 42 '.

Since the rotary drum filter 10 in the above embodiment is not provided with a color separation filter, the rotary drum 4 is not in operation during the reading of the original.
Although the second rotation is not performed, it may be applied to a color separation filter, and the rotary drum 42 may be rotated during one reading of the original to sequentially switch the filters 48.

Further, according to the above embodiment,
By arranging the mirror portion 11 at a high position, the optical path L becomes longer by the height of the mirror portion 11, and it becomes possible to arrange the camera 9 while ensuring a space for adjusting the position of the back portion of the camera 9, and with this The position of the camera 9 is lowered by tilting the axis so that the rear part of the camera 9 is lowered, and its position is lowered within a range where it does not interfere with the document table 5, and the aperture of the lens system 15 is increased with the increase of the document width. The height of the upper surface can be reduced while arranging it while suppressing the height of the upper surface, and the filter switching device can be made compact as described above, and the upper surface can be formed low enough to be used as a work desk space.
The document table 5 can be installed at a height with good workability.

[Brief description of drawings]

FIG. 1 is a schematic front view showing the entire configuration of a document reading device having a filter switching device according to an embodiment of the present invention, with a cover and the like removed.

FIG. 2 is a side view of FIG. 1 showing an optical system part omitted.

FIG. 3 is a front view of a filter switching device.

FIG. 4 is a side view of FIG. 3;

FIG. 5 is a front view showing an even filter arrangement and an optical path in a rotating drum.

FIG. 6 is a front view showing an odd filter arrangement and an optical path on a rotating drum.

[Explanation of symbols]

 1 Original Reading Device 2 Original Setting Section 3 Reading Section 4 Body Frame 5 Original Plate 6,7 Fiber for Reflecting Original Illumination 8 Fiber for Transparent Original Illumination 9 Camera 10 Rotating Drum Filter 11 Mirror 15 Lens System 16 Line Sensor 37 Mounting Frame 41 Support Frame 42 Rotating Drum 43 Rotating Side Plate 45 Rotating Shaft 47 Filter Mounting Plate 48 Filter 52 Switching Motor G Gap L Optical Path

Claims (2)

[Claims] 1. A document reading device for reading a document image by irradiating a document with linear light and forming reflected light or transmitted light on a line sensor through a rotary drum filter and a lens system to read a document image. A rotary drum filter is a filter in which the center part of the rotating side plates on both sides is rotatably supported by a rotating shaft, and a plurality of filter mounting plates that connect the rotating side plates on both sides in parallel to the rotating shaft are arranged adjacent to each other on the outer periphery at equal intervals. A filter is mounted on the filter mounting plate with a predetermined gap between the filter mounting plate and the mounting plate, and an optical path is formed through a gap between the filter mounting plate on the opposite side to the filter located in front of the lens system. A filter switching device in a document reading device. 2. The document reading apparatus according to claim 1, wherein a lens system is arranged at an eccentric position with respect to the rotary drum filter, and an optical axis passes through a position deviated from a rotation center of the rotary drum. Filter switching device.