JPH03209234A - Original cassette - Google Patents

Abstract

PURPOSE:To read an image accurately and precisely by selecting a size of a support plate to be a size which can be directly abutted to a cassette support body provided on a rotating table when positioning it inside an image reading device. CONSTITUTION:Because the size of a glass plate 26 is set to be a size which can be directly abutted to the rotating bodies 422a and 422b, the cassette 20 has its lower surface of its glass plate 26 retained to the rotating bodies 422a and 422b as reference surface. Therefore, a reference position in a focal direction of an image formation lens constituting the image reading device is in the position on the lower surface of the glass plate 26. As the result, the focal position of the read original is maintained in a good state regardless of variance in thickness of a frame body. Thus, reading of image information carried on the original can be carried out accurately and precisely.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Fields of Application] The present invention provides a means for maintaining a reading optical system in an accurate and stable state at all times when subjecting a document cassette that holds a document carrying image information to an image reading process. The present invention relates to a document cassette that allows document positioning.

[Conventional technology] For example, in the fields of printing and plate-making, image scanning scanning is a method in which image information carried on a manuscript is electrically processed to create a film master plate for the purpose of streamlining work processes and improving image quality. Regeneration systems are widely used.

In this case, in the image reading device constituting the image scanning reading and reproducing system, the original to be read is substantially stored in a cassette, and the cassette is conveyed in the sub-scanning direction via the document table while the illumination light source is attached. to strengthen That is, illumination light is irradiated in the main scanning direction, thereby two-dimensionally reading the image information carried on the original to be read.

The applicant has already developed various types of image reading devices and document reading cassettes and has filed patent applications.

In this case, the document cassette has a pair of support plates, at least one of which is made of a transparent material, and light reflected or transmitted from the document through the transparent support plates is provided in the reading section. Image information is read by being photoelectrically converted by a photo/electrical conversion element such as a CCD.

In the optical system provided in the reading section, the focal length with respect to the document is based on the position of the lower surface of the cassette frame of the document cassette. Therefore, the thickness of the cassette to which the support plate is attached and the thickness of the support plate must each be accurately ensured with an accuracy of several tens of microns.

[Problems to be Solved by the Invention] Therefore, when manufacturing this type of document cassette in a loft, it is difficult to manufacture cassettes in which the thickness of the cassette frame, the thickness of the support plate, etc. are the same in tens of microns. This is practically difficult, and it is unavoidable that variations in quality occur.

If the thickness or the like is non-uniform in this way, the optical system constituting the reading section will not be able to maintain a good focal length with respect to the document, causing a focus shift or a magnification shift. As a result, the disadvantage that image resolution deteriorates is exposed.

An object of the present invention is to ensure that the focal length of the optical system in the image reading device with respect to the document is always constant regardless of variations in the thickness of the cassette frame, the thickness of the support plate, etc. An object of the present invention is to provide a document cassette capable of reading image information.

[Means for Solving the Problems] In order to solve the above-mentioned problems, a document cassette according to the present invention includes: a transparent support plate for positioning and placing a sheet-like document carrying image information; a cassette frame defining an opening for fixing the plate; when the support plate is positioned within an image reading device;
It is characterized in that the size is selected to allow direct contact with the cassette support provided on the rotary table.

[Function] In the document cassette according to the present invention, the cassette support provided on the rotary table in the image recording device directly contacts the support plate that constitutes the document cassette and has a highly accurate smooth surface. The position of the lower surface of the support plate serves as a reference position in the focal direction of the optical system, allowing accurate and precise image reading.

[Embodiments] Next, preferred embodiments of the document cassette according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an image reading device 10 for reading image information carried on a document, preferably a film, using a document cassette according to the present invention. A cassette attaching/detaching section 14 is formed at one end of the upper part of the casing 12 that houses the image reading device 10, and a cassette 20 can be introduced into the casing 12 through this cassette attaching/detaching section 14, and the cassette 20 can be inserted into the casing 12. Ejection of said cassette 20 from within takes place.

Here, the cassette 20 has a frame 22 shaped into a substantially rectangular shape.
V-shaped grooves 2 are provided on both sides of the frame body 22 in the transport direction.
4a and 24b are shaped, and a light-transmitting member, for example, a glass plate 26, is attached to the frame 22. At one end of the frame 22, a glass plate 28, which is also a light-transmitting member, is provided.
is swingably supported via a hinge member 30,
The original document S to be read is supported by the glass plate 28 and the glass plate 26 (see FIGS. 4 and 5).

In this case, as understood from FIG. 4, the glass plate 26
is larger in area than the glass plate 28, and the end surface of the glass plate 26 is firmly attached to the side wall defining the recess 32 carved in the frame 22 via an adhesive or the like. put. Therefore, as will be described later, when reading an image, the rotating bodies 422a and 4 provided on the rotating table 302 are
22b can directly contact the glass plate 26 and hold it horizontally.

A cassette insertion opening 40 is provided adjacent to the cassette attachment/detachment section 14.
A linear solenoid 52 constituting a locking mechanism 50 is provided near the cassette insertion opening 40, and one end of a locking member 58 is swingably connected to the linear solenoid 52. Ru. Therefore, the other end of the locking member 58 enters the cassette insertion opening 40 under the driving action of the linear solenoid 52, and a new cassette 20 is accidentally inserted into the housing 12 through the cassette insertion opening 40. It can be prevented from being imported.

One end of a transport mechanism 100 is disposed close to the locking mechanism 50, and the other end of the transport mechanism 100 extends above a rotary table 302, which will be described later.

As shown in FIG. 1, the transport mechanism 100 includes a frame 102.
A plurality of rods 104 are fixed upright to one end of the frame 102 along the conveying direction, and a guide roller 106 that is engaged with one V-shaped groove 24H of the cassette 20 is supported by the rod 104. be done. frame 1
Similarly, the other V-shaped groove 24 of the cassette 20 is connected to the other end of the cassette 20 via a plurality of ronds 108 along the conveying direction.
A guide roller 110 that engages with b is provided.

A rotational drive source 114 is fixed to the frame 102, and one end of a timing belt 118 engages with a pulley 116 that is pivotally attached to a drive shaft of the rotational drive source 114. The timing belt 118 is connected to a pair of rollers 120 via a torque transmitting means 119 including a gear train 16 and a gear train that engages with the timing belt 118.
, the first conveyance roller group 122 and the second conveyance roller group 12
4 is rotated. The first transport roller group 122 includes a plurality of rotating shafts 130 that rotate via a rotational force transmitting means 119.
A pair of conveying rollers 1 are mounted on the rotating shaft 130 at a predetermined distance to engage with the upper surface of the frame 22 of the cassette 20.
32 is pivoted. On the other hand, the second conveyance roller group 124 is
A plurality of rotating shafts 1 similarly engaged with the rotational force transmission means 119
36, and a pair of conveyance rollers 138 are each pivotally attached to the rotating shaft 13G, and the conveyance rollers 138 are configured to be freely movable up and down via a displacement mechanism (not shown) including a cam.

Below the first and second conveyance roller groups 122 and 124 constituting the conveyance mechanism 100, a document table 200 is disposed so as to be movable forward and backward in the sub-scanning direction (arrow 8 direction) via a sub-scanning mechanism 202. The sub-scanning mechanism 202 has a rotational drive source 204.
A ball screw 206 is connected to this rotational drive source 204, and this ball screw 206 is fitted into a nut member 208 fixed to one side of the document table 200.
Both sides of the document table 200 are held by guide bars 210.

A cassette 20 is placed on the document table 200 in the trimming direction,
That is, a trimming mechanism 250 is provided that moves forward and backward in a direction perpendicular to the sub-scanning direction (direction of arrow A). The trimming mechanism 250 has a rotational drive source 252 attached to the document table 200, and one end of a ball screw 254 is connected to this rotational drive R252. This ball screw 254
extends in the trimming direction, fits into a nut member (not shown) provided on the trim table 256, and the other end is supported by the document table 200. There is a tray on the document table 200.
A pair of guide bars 260 extending in the direction of the trimming and parallel to each other are fixedly installed, and a trim base 256 is supported by the guide bars 260.

A relatively large-diameter opening 262 is formed in the trim table 256, and guide rollers 264a and 264b are arranged on the same straight line as the guide rollers 106 and 110 that constitute the conveyance mechanism 100 in the vicinity of the opening 262. is supported. Furthermore, a rotation mechanism 300 for rotating the cassette 20 by a predetermined angle on the trim base 256;
A cassette positioning mechanism 400 according to this embodiment is provided for positioning and holding the cassette 20 on a rotary table 302 comprising a rotary table 302 .

A gear train is connected to a rotation drive source (not shown) constituting the rotation mechanism 300, and this gear train meshes with a ring-shaped gear 318 fixed to the rotary table 302, and the rotary table 302 Support rollers 3] Oa, 310b and 3 disposed on the trim base 256
12a, 312b.

The cassette positioning mechanism 400 is an actuator fixed to the bottom side of the trim base 256, for example, a rotary drive source 4.
02, and a cam plate 4 is attached to the rotating shaft of this rotational drive source 402.
04 is engaged (see FIGS. 1 to 3). A locking means 405 is disposed on the rotary table 302 at an angular position for attaching and detaching the cassette 20 and is engageable with a cam plate 404 .

The locking means 405 includes a slide member 406, and a rack 408 is integrally formed with the slide member 406. A coil spring 410 is engaged with the end of the slide member 406, and the slide member 406 is always urged toward the cam plate 404 through the elastic force of the coil spring 410.

A pinion 412 meshes with the rack 408, and one end of a locking plate 414 is locked to the pinion 412, and the locking plate 414 is bent midway and has an elastic member 4 at the other end.
16 is attached. Therefore, when no external force is applied to the slide member 406, the locking plate 414 swings vertically upward under the elastic force of the coil spring 410, and the end surface of the cassette 20 is pressed by the elastic member 416. on the other hand,
When the cam plate 404 engages with the slide member 406, the locking plate 414 is swung horizontally, and the elastic member 416 is retracted inward of the rotary table 302.

In this embodiment, the slide member 406 is pressed by a cam plate 404 connected to a rotational drive source 402, but the slide member 406 is connected to a linear solenoid and is moved forward and backward by a rod (not shown). It may also be pressed through the

As shown in FIG. 2, a stopper 41g is fixed to the rotary table 302 facing the elastic member 416, and elastic members 420a and 420b that are engaged with the ends of the cassette 20 are provided on the end surface of the stopper 418. will be provided. A plurality of rotating bodies 422a and 422b are disposed on the rotary table 302 between the locking plate 414 and the stopper 418 and engaging the bottom surface of the glass plate 26 constituting the cassette 20, respectively. In this case, the rotating bodies 422a, 422b
The fixed shafts 424a and 424b supporting the rotary table 302 are placed directly on the upper surface 302a of the rotary table 302, thereby making it possible to accurately maintain the height position of the cassette 20 with respect to the rotary table 302 (see FIG. 4). )
.

A guide means 425 that can position and hold the cassette 20 in the optical axis direction (described later) is disposed on the rotary table 302. The guide means 425 includes a rod 426 that is vertically supported on the outside of the rotating body 422a, and the rod 426 is configured to be able to rise and fall freely through the elastic force of a coil spring 428, and its A guide roller 430 is supported at the upper end. On the other hand, a plurality of rods 431 are disposed on the outside of the rotary body 422b and are oriented in the vertical direction. It is configured to be able to swing freely with the bin 436 as a fulcrum, and a guide roller 438 is supported at the end thereof.

A light source 450 constituting a transmitted illumination mechanism is provided within the housing 12 and extends in the main scanning direction that is substantially orthogonal to the eight directions of the arrows. An image reading unit 500 that photoelectrically reads the light L is provided.

The image reading section 500 includes a bracket 502, and the bracket 502 is arranged in the optical axis direction (direction of arrow I in FIG. 1).
It is engaged with a ball screw 504 extending in the direction of the optical axis P, and is configured to be movable forward and backward in the direction of the optical axis P under the driving action of a rotational drive source 506 connected to the ball screw 504. A rotary table 51 is attached to the upper part of the bracket 502 via a support shaft 508.
0 is supported, and the bracket 5 is supported on this rotary table 510.
A bell }514 that engages with a rotational drive source 512 fixedly attached to 02 is tensioned. A plurality of imaging lenses 516 are housed in holders 518 and spaced apart from each other by equal angles on the rotating table 510.

Further, a ball screw 520 is supported by the bracket 502 so as to extend in the direction of the optical axis P in parallel with the ball screw 504, and a rotary drive source 522 is connected to an end of the ball screw 520. It is engaged with the ball screw 520. A holder 528 is attached to the movable base 526, and a first CC is introduced into the holder 528, into which illumination light L separated into three directions by a glimmer (not shown) is introduced.
D530a and 2nd C C D530b and 30th C C
D530C is provided. In that case, the said No. IC
The CCD 530a to the third CCD 530c photoelectrically read the color image information carried on the read document S as image information corresponding to each color of R, G, and B.

The image reading apparatus incorporating the document cassette according to this embodiment is basically constructed as described above, and its operation will be described next.

When the cassette 20 containing the desired document S to be read is inserted into the cassette insertion opening 40 from the cassette attachment/detachment section 14,
The leading end of the cassette 20 is held between the pair of rollers 120, and the rotational drive source 114 is driven. For this reason, Boo! The roller pair 120, the first conveyance roller group 122, and the second conveyance roller group 124 are integrally rotationally driven via the timing bell [18 and the rotational force transmission means 119]. Therefore, the cassette 20 with the frame body 22 held between the roller pair 120 is transferred to the first conveyance roller group 122 side, and the conveyance rollers 132 constituting the first conveyance roller group 122 touch the upper surface of the frame body 22. V-shaped grooves 24a formed on both sides of the frame 22,
The guide rollers 106 and 110 are fitted into the rollers 24b, and the cassette 20 moves toward the second transport roller group 124 side.

Conveyance rollers 138 constituting the second conveyance roller group 124 and guide means 425 provided on the rotary table 302
After the leading end of the cassette 20 comes into contact with the stopper 418 under the guidance of guide rollers 430 and 438, the drive of the rotary drive source 114 is stopped. Here, the rod 426 supporting the guide roller 430 is biased toward the rotary table 302 via a coil spring 428, and the guide roller 438 is biased toward the rotary table 302 and the guide via the coil springs 432 and 434. It is urged toward the roller 430 side. Therefore, the cassette 20 is resiliently supported on both sides by the guide rollers 430 and 438, and the glass plate 26 is pressed against the rotating bodies 422a and 422b to determine its height position relative to the rotating table 302, that is, in the direction of the optical axis P. The position of will be adjusted.

Next, the rotational drive source 402 that constitutes the cassette positioning mechanism 400 is driven, and the cam plate 404 is rotated by a predetermined angle so that its small diameter portion faces the slide member 406 that constitutes the locking means 405 (see FIG. 3). ). Therefore, the slide member 406 is displaced toward the cam plate 404 through the elastic force of the coil spring 410, and the pinion 412 that is engaged with the rack 408 provided on the slide member 406 rotates and is locked. The plate 414 swings vertically upward, and the elastic member 416 presses the cassette 20 toward the stopper 418 . With this, the cassette}20
is held in position with respect to the rotary table 302 in a direction substantially perpendicular to the direction of the optical axis P.

As is well known, the accuracy of the smooth surface of the glass plate 26 can generally be easily ensured. Therefore, in the present invention, in view of this point, the rotating bodies 422a and 422b are brought into direct contact with the lower surface of the glass plate 26, and the cassette 2
It is configured to hold 0. Therefore, if the focal position of the optical system is set to correspond to the lower surface of the glass plate 26, image information can be read with high accuracy.

After the cassette 20 is positioned and held on the rotary table 302, the displacement mechanism 140 is driven and the second transport roller group 124 is separated from the cassette 20.

Next, in order to adjust the angular position of the document S to be read held in the cassette 20, the rotation mechanism 300 is driven as necessary. Further, in order to trim the read document S, the trimming mechanism 250 is driven as necessary. That is,
The trim table 256 is displaced in a direction substantially perpendicular to the sub-scanning direction under the driving action of the rotational drive source 252, and thereby the trimming operation of the read document S is performed mechanically.

In this way, after the cassette 20 is positioned with respect to the document table 200, the rotational drive source 2 constituting the sub-scanning mechanism 202 is rotated.
04 to energize the light source 450 while the document table 200 is conveyed in the sub-scanning direction (in the eight directions of arrows) via the guide bar 210 under the rotational action of the ball screw 206. Therefore, when the illumination light L derived from the light source 450 passes through the read original S in the main scanning direction, the color image information carried on the read original S is extracted as an optical signal.
This image information as an optical signal is transmitted to a predetermined imaging lens 5 which is placed on the optical axis P under the action of a rotational drive source 512 in advance.
16 to each CCD 530a to 530C. As a result, the color image information as the optical signal corresponds to each color of R, G, and B.
It is read out photoelectrically by 30a to 530c. During this time, the document table 200 is being conveyed in the sub-scanning direction in the eight directions of the arrow, and the document S to be read is two-dimensionally irradiated with the illumination light L, and its color image information is taken out, and the color image information is extracted from each CCD53.
All will be read by 0a to 530C.

In this case, the cassette 20 is positioned on the rotary table 302 in the direction of the optical axis P via the guide means 425, and is also positioned in a direction substantially perpendicular to the direction of the optical axis P by the guide means 425 and the lock means 405. There is. Therefore, it is possible to read the image information carried by the original document S stored in the cassette 20 with high precision.

After the reading work of the original document S is completed, the sub-scanning mechanism 202
After moving the document table 200 in the direction opposite to the direction of the arrow 8 under the action of the rotational drive source 204 comprising a rotation drive source 204, the trimming mechanism 250 and the rotation mechanism 300 are driven as necessary;
The rotary table 302 is positioned at the cassette 20 attachment/detachment position. Here, the displacement mechanism 140 is driven to bring the conveyance rollers 138 that constitute the second conveyance roller group 124 into contact with the upper surface of the frame 22 of the cassette 20, and the rotational drive source 402 that constitutes the cassette positioning mechanism 400 is driven. The large diameter side of the cam plate 404 is moved by the sliding member 4 under the driving action of
06, the locking plate 414 is separated from the cassette 20 and retracted into the rotary table 302.

Therefore, under the driving action of the rotary drive source 114 that constitutes the transport mechanism 100, the Boo! Rotate Jl 16 in the opposite direction to the above, and open timing bell port 18 and rotational force transmission means 119.
The second conveying roller group 124 and the first conveying roller group 12
2 and the pair of rollers 120 are driven, thereby causing the cassette 20 to be led out from the cassette attachment/detachment section 14.

At this time, if the locking member 58 is previously released from the cassette insertion port 40 under the action of the locking mechanism 50, the cassette 20 can be carried out to the outside through the cassette insertion port 40.

As explained above, in this embodiment, the size of the glass plate 26 is set to be such that it comes into direct contact with the rotating bodies 422a, 422b, so the cassette 20 uses the lower surface of the glass plate 26 as the reference surface. As the rotating bodies 422a, 42
2b, and the reference position in the focal direction of the imaging lens 516 that constitutes the image reading device 10 is the lower surface position of the glass plate 26.

As a result, the focal position of the read document S is maintained in a good condition despite the variation in the thickness of the frame 22, so defocus, image magnification, etc. are avoided, and an image with excellent resolution is obtained. It will be done.

Note that in an image reading device configured so that the operator manually sets the cassette 20, the rotating bodies 422a and 422b provided on the rotating table 302 of the previous embodiment are
Instead, a protruding cassette holder and the support plate 112 may be provided so as to be in direct contact with each other, and the lower surface of the glass plate 26 may be placed directly on the cassette holder.

[Effects of the Invention] As can be understood from the above description, in the document cassette according to the present invention, the support plate made of a gas plate or the like that holds the read document is directly connected to the rotating body or the cassette holder in the image reading device. It is possible to make contact.

Therefore, in the optical system within the image reading device, image information carried on the document can be read using the lower surface position of the support plate as a reference position.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of the structure of an image reading device, Fig. 2 is a schematic perspective view of a cassette positioning mechanism incorporated in the device shown in Fig. 1, and Fig. 3 is a diagram of a locking means and actuator that make up the cassette positioning mechanism. FIG. 4 is a vertical sectional view showing the engagement relationship between the cassette positioning mechanism and the cassette, and FIG. 5 is a perspective explanatory view of the cassette. DESCRIPTION OF SYMBOLS 10... Image reading device 14... Cassette attachment/detachment part 20... Cassettes 26, 28... Glass plate 100... Transport mechanism 140... Displacement mechanism 200... Document table 202... Sub Scanning mechanism 250...trimming mechanism 300...rotation mechanism 400...cassette positioning mechanism 402...rotary drive source 405...locking means 414...locking plates 422a, 422b...rotating body 425 ...Guide means 430, 43g...Guide roller 450...Light source 500...Image reading section

Claims (1)

[Claims] 1) A transparent support plate for positioning and placing a sheet-like original carrying image information; and a cassette frame defining an opening for fixing the support plate; When the support plate is positioned within the image reading device,
A document cassette characterized in that the size is selected to allow direct contact with a cassette support provided on a rotary table.