JPH104476A - Image scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a blur and deformation of image by blocking the vibration of mirror with a great moment of inertia at the time of scan by constituting a flywheel so that its inertia moment can be reduced at the time of return. SOLUTION: A flywheel 1 is constituted by providing a ratchet mechanism 4 outside an inner wheel part 3, which is always integrally rotated while being fixed on a shaft, and providing an outer wheel part 2 outside this ratchet mechanism 4. At the time of return when a stepping motor is rotated backward, the inner wheel part 3 integrated with the shaft is rotated in counter-clock-wise direction. At such a time, since a lock member 5 consisting of the ratchet mechanism 4 moves toward the inner wheel part 3 against a spring 6 and the other end of the lock member 5 successively moves over sawteeth provided on the inner peripheral surface of the outer wheel part 2, the outer wheel part 2 is prevented from being rotated while following up the rotation of the inner wheel part 3. Namely, since the ratchet mechanism 4 gets inactive and only the inner wheel part 3 is operated as the inertial mass of the flywheel 1, the effect is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image scanner, and more particularly, to miniaturization and power saving of a driving source used for a mirror scan, thereby reducing overall size and power consumption.
And an image scanner with low cost.

[0002]

2. Description of the Related Art Generally, in a copying machine, a facsimile, and an image input device of a personal computer,
An image scanner using a CCD line sensor is configured as shown in FIGS.

That is, a pair of rails 3 for supporting a mirror in the operation direction are provided on the inner surfaces of the frame body 31 whose top and bottom are open.
4 and 34 are provided. A machine base 36 is provided between the rails 34 and 34, on which the first mirror unit 35 is located on the upper surface, and a machine base 38 on which the second mirror unit 37 is located on the upper surface. Have been. The first mirror 32 is connected between the first mirror unit 35 and the machine base 36, and the second mirror unit 37 is connected to the machine body 38.
Thus, the second mirror 33 is formed. Also,
Reference numeral 39 denotes a lens barrel provided with a CCD line sensor.

[0004] Further, the frame 31 on both ends of the rails 34, 34 has a shaft 4 orthogonal to the rails 34, 34.
0 and 41 are respectively installed, and one shaft 4
0 extends outside the frame body 31 so that the flywheel 42
Is installed. A drive transmission pulley 43 is provided on a portion of the shaft 40 inside the frame 31, and is provided between the shaft 40 and a drive shaft of a stepping motor 44 which is a drive source attached to the outside of the frame 31. Is provided with a timing belt 45.

A pulley 46 for the first mirror 32 and a pulley 46 for the second mirror 33 are attached to the shafts 40 and 41, respectively.
a, 46b, 47a, 47b are provided, and a wire 48 having one end fixed to the frame 31 is provided with pulleys -46a for the first mirror 32 and the second mirror 33 provided on both shafts 40,41. , 46b, 47a, 47
b, the other end is fixed to the frame 31 after the base 36 of the first mirror 32 and the base 38 of the second mirror 33 are looped around.

As described above, the first mirror 32 and the second mirror 33 move along the rails 34 in a predetermined relationship when the stepping motor 44 is driven by winding the wire 48 around.

In the mirror type scanner as described above, accurate position control and speed control can be performed by simple control. Therefore, a stepping motor is generally used as a drive source for driving mirror scan. is there.

However, since the stepping motor rotates by a predetermined angle for each drive signal, it gives a vibration to the mirror, and this vibration causes blurring of the image and deformation of the image.

In order to solve such a problem, as described above, one end of one shaft 40 is extended to the outside of the frame body 31 and a flywheel 42 is attached to smooth the rotation of the stepping motor 44. , FIG. 10,
As shown in FIG. 11, a machine base 36 constituting the first mirror 32
A magnet 49 is provided on the lower surface of the motor to increase the frictional force by applying a suction force to the rail 34, and a means for absorbing the vibration by the frictional force and a means for using a rotation speed region where the vibration of the stepping motor is small. Has been adopted.

In the above-mentioned means, the means for extending one end of one shaft 40 to the outside of the frame 31 and attaching the flywheel 42 to smooth the rotation of the stepping motor 44 has the following problems. Occurs.

That is, the operation of the image scanner includes a scan operation for taking in an image and a return operation for returning the mirror to the scan start position. Normally, the rotation speed of the stepping motor at the time of return is about six times the rotation speed at the time of scanning, and the rotation speed of the stepping motor at the time of return becomes high. The torque decreases.

In general, a stepping motor cannot be started at a high speed, so that it is started at a low speed and accelerates to a high speed. At the time of acceleration, the product of inertia of a flywheel or the like and acceleration is added to the motor load. And
Smooth rotation and starting up to high speed in a short time were contradictory.

As a countermeasure against this, it is conceivable to use a high-output motor. However, in this case, the motor becomes large and the current consumption increases, and when the flywheel is made small, the effect of the flywheel decreases. Therefore, there is a problem that the mirror vibrates.

The present invention reduces the load during acceleration at the time of return without increasing the size of the drive source and the size of the flywheel, and quickly starts up to a high speed while keeping the rotation of the drive source smooth. It is an object of the present invention to provide an image scanner capable of performing a smooth return operation.

[0015]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention transmits a driving force of a driving source that rotates forward and backward to scan and return a mirror, and reads an image during a scanning operation. At the same time, the mirror scan type image scanner in which the return operation is performed at a speed higher than that in the scan operation and in the opposite direction and the movement is smoothly performed by the flywheel is performed. It is configured to be sometimes smaller.

The flywheel is composed of an inner ring portion that rotates integrally when the drive source is driven, an outer ring portion, and a ratchet mechanism that integrates the inner ring portion and the outer ring portion, or separates them from each other. At times, the inner ring portion and the outer ring portion are configured as separate bodies. Further, it has a configuration using a stepping motor as a driving source.

[0017]

Since the present invention is constructed as described above, the flywheel provided for reducing the vibration of the stepping motor operates during scanning and becomes inactive during returning, so that the returning operation can be performed in a short time. It will be possible to get up fast.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image scanner according to the present invention shown in the drawings will be described below. 1 to 5 show an image scanner according to the present invention. FIG. 1 is an overall schematic diagram of the image scanner, FIG. 2 is a schematic diagram showing a state where a part is removed, and FIG. 3 uses a ratchet mechanism. FIG. 4 is a schematic diagram showing an inoperative state of a flywheel, FIG. 4 is a schematic diagram showing an operating state of a flywheel using a ratchet mechanism, and FIG. 5 is a diagram showing an inner ring portion, an outer ring portion, and a ratchet mechanism of a flywheel using a ratchet mechanism. FIG.

In the overall schematic diagram of the image scanner, the same members as those of the prior art are denoted by the same reference numerals, and detailed description thereof will be omitted. In the image scanner according to the present invention, the flywheel 1 attached to a portion of the shaft 40 located outside the frame 31 includes an inner ring portion 3 fixed to the shaft 40 and integrally rotating, and a flywheel 1 positioned outside the frame. And a ratchet mechanism 4 that rotates the outer race 2 integrally with the inner race 3 or does not rotate the outer race 2.

That is, the ratchet mechanism 4 is provided outside the inner ring portion 3 which is fixed to the shaft 40 and always rotates integrally. The flywheel 1 is formed by providing the outer ring portion 2 outside the ratchet mechanism 4. ing.

As shown in FIG. 5, the ratchet mechanism 4 is provided with a locking member 5 having one end pivotally mounted in a concave portion 3a provided on the outer peripheral surface of the inner ring portion 3, and the locking member 5 has a concave portion. The spring 6 is always urged in a direction away from the inner ring part 3 by a spring 6 located in the inside 3a. On the other hand, the inner peripheral surface of the outer ring portion 2 located on the outside is formed in a sawtooth shape, and the other end of the locking member 5 is located in the sawtooth.

As shown in FIG. 4, at the time of scanning in which the shaft 40 and the inner ring 3 rotate clockwise through the timing belt by the stepping motor 44, the other end of the locking member 5 has a deep saw tooth. The inner ring portion 3 and the outer ring portion 2 are integrated by the ratchet mechanism 4 because the outer ring portion 2 follows the rotation of the inner ring portion 3, whereby the outer ring portion 2 rotates. Since the moment increases, the effect as a flywheel is great.

On the other hand, at the time of return in which the stepping motor 44 rotates in the direction opposite to the above, the inner ring 3 integral with the shaft 40 rotates counterclockwise as shown in FIG. At this time, the locking members 5 constituting the ratchet mechanism 4
Moves in the direction of the inner ring portion 3 against the spring 6, and the locking member 5
The other end of the outer ring portion 2 sequentially rides over the saw teeth provided on the inner peripheral surface of the outer ring portion 2, so that the outer ring portion 2 does not rotate following the rotation of the inner ring portion 3. That is, since the ratchet mechanism 4 is not operated, only the inner ring portion 3 acts as the inertial mass of the flywheel 1, so that the effect as the flywheel is small.

FIGS. 6 and 7 show another embodiment of the flywheel. The flywheel 1 shown in this embodiment is shown in FIGS.
Reference numeral 0 denotes a partition plate 13 having a shaft 40 connected to the center of a cylindrical case 11, a liquid 12 sealed therein, and one end pivotally connected to a portion near the inner peripheral surface.
Are provided. Even in the flywheel 10 configured as described above, at the time of scanning, a large amount of the liquid 12 is located between the partition plates 13 by turning each partition plate 13 in the radial direction as shown in FIG. Since the liquid 12 rotates integrally, the moment of inertia increases and the effect as a flywheel increases.

On the other hand, at the time of return shown in FIG. 6, since each partition plate 13 faces the circumferential direction, the amount of liquid 12 partitioned by each partition plate 13 becomes small, and the mass of the liquid that rotates integrally is reduced. Since it is small, the moment of inertia is small, and the effect as a flywheel is small.

In the above-described embodiment, the means using the ratchet mechanism and the liquid using the liquid are shown as means for changing the mass of the flywheel between the time of scanning and the time of return. However, the present invention is not limited to this. In short, any configuration can be adopted as long as the moment of inertia can be changed depending on the rotation direction.

[0027]

As described above, according to the present invention, the rotational direction of the drive source, that is, the moment of inertia of the flywheel can be changed between the time of scanning and the time of return. Can be prevented, whereby blurring of the image and deformation of the image can be prevented. Further, at the time of return, the mass of the flywheel becomes small, so that the drive source can be rotated at high speed in a short time. Therefore, the load during acceleration at the time of return can be reduced without increasing the size of the drive source and the size of the flywheel, making it possible to start up to a high speed in a short time while keeping the rotation of the drive source smooth and smooth. This has the effect that a proper return operation can be performed.

When a stepping motor is used as a driving source, the output torque decreases at high speed rotation.
At this time, since the moment of inertia acting as a load is small, there is an effect that even a stepping motor having a small output can be used.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram of an image scanner according to the present invention.

FIG. 2 is a schematic view showing a state in which a part of FIG. 1 is removed.

FIG. 3 is a schematic diagram showing a state where the mass of the flywheel is small.

FIG. 4 is a schematic diagram showing a state where the mass of the flywheel is large.

FIG. 5 is a schematic diagram showing an inner ring portion, an outer ring portion, and a ratchet mechanism of the flywheel.

FIG. 6 is a schematic view showing another example of the flywheel and showing a state where the mass is small.

FIG. 7 is a schematic diagram showing a state where the mass shown in FIG. 6 is large.

FIG. 8 is an overall schematic diagram of a conventional image scanner.

FIG. 9 is a schematic view showing a state where a part of the structure shown in FIG. 8 is removed.

FIG. 10 is a schematic diagram showing a configuration for absorbing a vibration by increasing a frictional force by applying a suction force between a machine base constituting a mirror and a rail;

FIG. 11 is a schematic side view of what is shown in FIG.

[Explanation of symbols]

 1, 10, 42 ... flywheel 2 ... outer ring 3 ... inner ring 3a ... recess 4 ... ratchet mechanism 5 ... locking member 6 ... spring 11 ... case 12 ... ... liquid 13 ... partition Plate 31 Frame 32 First mirror 33 Second mirror 34 Rail 35 First mirror section 36, 38 Machine base 37 Second mirror section 39 Lens barrel section 40, 41 shaft 44 stepping motor 45 timing belt 43, 46a, 46b, 47a, 47b pulley 48 wire 49 magnet

Claims (3)

[Claims] 1. A mirror for scanning and returning by transmitting a driving force of a driving source that rotates forward and backward, reads an image during a scanning operation, and operates at a higher speed in a returning operation than in a scanning operation and in a reverse direction. The mirror scanner type image scanner wherein the movement is smoothed by a flywheel, wherein the flywheel is configured so that its moment of inertia is reduced upon return. 2. The flywheel includes an inner ring portion that rotates integrally when a driving source is driven, an outer ring portion, and a ratchet mechanism that integrates the inner ring portion and the outer ring portion, or separates them. 2. The image scanner according to claim 1, wherein said inner ring portion and said outer ring portion are separated during operation. 3. The image scanner according to claim 1, wherein said driving source is a stepping motor.