JP3358333B2 - Document scanning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document scanning device used for an electrophotographic copying machine, an image scanner, or the like.

[0002]

2. Description of the Related Art In an electrophotographic copying machine, an image scanner, or the like, a document scanning device for scanning an image of a document is used in order to read the image of the document.

In this document scanning apparatus, an image of a document surface is read by scanning an image sensor (line sensor) such as a CCD, a mirror, and a light source on the document surface. The original is read during the forward movement, and after the original is read, the original is moved back to the initial position (home position) and the next scanning is started.

In such a document scanning apparatus, when the scanning operation is started, the movable portion may vibrate, and a problem may occur in reading the document. In particular, when the document is continuously read, that is, when the reciprocating operation is continuous, the vibration is remarkably generated when the document moves from the backward movement to the forward movement.

Conventionally, in order to suppress the vibration of the movable portion, the structure of the document scanning device including the movable portion (scanning means) is made thicker and has a high rigidity. I try to suppress. However, simply increasing the rigidity of such a structure does not completely suppress the vibration.The moving member is stopped for a certain period after the scanning is completed, and the next scanning operation is performed after the vibration completely stops. Controlled to start.

[0006] Also, Japanese Patent Application Laid-Open No. 4-56839 discloses that
A manuscript that is provided with a mass body and an actuator that vibrates the mass body on a moving body that moves for scanning of the manuscript, and that applies vibration opposite to the vibration of the moving body to the mass body to cancel the vibration of the moving body. A scanning device is disclosed.

FIG. 11 is a perspective view of the document scanning device described in the above-mentioned publication. This document scanning device is mounted inside an electrophotographic copying machine, and the document surface placed on the document table 2 The original is read by scanning with two moving members 41 and 42. The moving member 41 has a lamp 4 as a light source.
1b, a reflecting plate 41c for guiding the light from the lamp 41b to the original surface, and a reflecting member 41c for transmitting the reflected light from the original surface to the other moving member 42.
The other moving member 42 is provided with mirrors 42b and 42c for guiding light from the mirror 41d to an optical lens inside a copying machine (not shown).

[0008] The two moving members 41,
Reference numeral 42 operates on the slide bar 11 and the slide plate 12 by a drive system including a motor and wires (not shown). The moving member 41 has a vibration pickup 41 e for detecting vibration of the moving member 41 and a damper 4.
1f, and an actuator and a mass body are disposed inside the damper 41f. An actuator inside the damper causes the mass body to vibrate so that an acceleration opposite to the acceleration of the vibration detected by the vibration pickup 41e is applied, thereby suppressing the vibration of the moving member 41.

[0009]

However, in the conventional method, simply increasing the rigidity of the structure does not have a rapid effect as a vibration suppression effect, and after all, the vibration is completely eliminated from the end of scanning to the next scanning. Must be stopped until no more. Therefore, when scanning is repeated continuously,
There is a problem that the scanning efficiency is reduced due to the waiting time.

In the apparatus disclosed in Japanese Patent Application Laid-Open No. 4-56839, a vibration pickup, a mass body, and a damper containing an actuator are mounted on a moving body thereof, which complicates the structure of the apparatus. However, there is a problem that the device becomes large and heavy, which leads to an increase in cost.

In view of the above, the present invention provides a document scanning apparatus in which the structure is not made heavy and rigid in order to prevent vibration, and the vibration of the movable portion is prevented without providing a special mechanical mechanism. To provide.

[0012]

According to a first aspect of the present invention, there is provided a document scanning apparatus for scanning a document image by reciprocating a scanning of a document image. The document scanning apparatus according to claim 1, further comprising control means for instructing the scanning means to start scanning forward movement at a timing when a vibration having a phase opposite to that of the vibration generated by the scanning is generated.

Further, in the first aspect of the present invention, the timing is a time when a time which is a natural number times a cycle of a vibration generated by braking of the scanning means has elapsed. Sa
Further, in the first aspect of the present invention, the control means may include
When the scanning means is stopped, the fundamental frequency of the natural vibration of the scanning means
An oscillator that outputs an oscillation signal having the same frequency as
The oscillation signal of the vibrator is input and the
Monostable multiple that generates pulses with the same cycle as the cycle
A vibrator, and synchronized with the pulse,
The scanning means is moved forward.

According to a second aspect of the present invention, there is provided an original scanning apparatus in which a scanning unit moves to read an original image. A document scanning apparatus comprising a control means for instructing a start of a scanning movement of the scanning means at a timing when the movement is stopped by moving the distance and a vibration having a phase opposite to the vibration generated by the minute distance movement is generated.

In the second aspect of the present invention, the minute distance movement is in the same direction as the scanning movement direction of the scanning means, and the timing is a natural number multiple of half the period of the vibration generated by the minute distance movement. It is characterized by the passage of time.

In the second aspect of the present invention, the minute distance movement is in a direction opposite to a scanning movement direction of the scanning means, and the timing is a natural number multiple of a period of a vibration generated by the minute distance movement. It is characterized by the passage of time. Further, in the second invention, the control means
The step is a half-period cycle of the natural oscillation cycle of the scanning means.
A monostable multivibrator that generates loose
Monos that generate pulses with a cycle shorter than the half cycle
A table multivibrator, and the half cycle
Performs the minute distance movement with shorter period pulses
And the scanning means is synchronized with the pulse of the half cycle.
Is moved forward.

[0017]

The present invention configured as described above operates as follows.

First, according to the first aspect of the present invention, when re-scanning is started, vibration is generated in a phase opposite to that generated when a regenerative brake is applied during braking (during braking). By controlling the control means so as to start the scanning forward movement of the rescanning, the vibration generated by the braking at the time of the backward movement of the scanning means is canceled by the vibration of the opposite phase, and the scanning means at the time of the forward movement of the rescanning. Is suppressed.

Further, by setting the start timing of the re-scanning to be a natural number times the oscillation period generated by the braking during the backward movement, the vibration caused by the braking during the backward movement and the vibration caused by the start of the scanning can be eliminated. Since the vibrations are caused by the natural periods having opposite phases, the vibration caused by the braking at the time of the backward movement is canceled by the vibration at the start of the scanning, and the vibration of the scanning means at the time of the forward movement of the rescanning is suppressed.

Next, according to a second aspect of the present invention, when the scanning movement is started from a completely stopped state, the scanning means is moved a small distance in advance and temporarily stopped, thereby generating vibrations in the scanning means. When the scanning movement is started again at the timing when the vibration having the opposite phase occurs, the vibration generated by the start of the scanning movement is canceled by the vibration generated by the movement of the minute distance, so that the vibration of the scanning unit is suppressed. You.

In the second aspect of the present invention, when the movement of the minute distance is in the same direction as the scanning movement direction, the vibration caused by the minute movement and the vibration caused by the start of the scanning movement occur in the same phase. By setting the timing of the start of the scanning movement to be a time that is a natural number times a half of the oscillation period, the vibration due to the minute movement and the vibration due to the start of the scanning are in opposite phases to cancel each other.

Conversely, if the movement of the minute distance is in the opposite direction to the scanning movement direction, the vibration caused by the minute movement and the vibration caused by the start of the scanning movement occur in opposite phases. Is set to the time when a natural number times the oscillation period elapses, the vibration due to the minute movement and the vibration due to the start of scanning are in opposite phases to each other and cancel each other.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a drawing showing the configuration of an electrophotographic copying machine using the original scanning device of the present invention, and FIG. 2 is a perspective view showing the mechanical configuration of the original scanning device. FIG. 3 is a block diagram showing a configuration of a control system of the document scanning device. It should be noted that FIG.
Members having the same functions as in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

As shown in FIG. 1, this electrophotographic copying machine has a transparent platen 2 and a platen 2
It has a light-shielding plate 3 for blocking light from shining on the original placed on the upper side, and scanning units 41 and 42 constituting an original scanning device 4 inside the copying machine main body 1 and an image for transferring an image to paper. The processing unit 5 is placed. Scanning unit 41
And 42 reciprocate, irradiate the original surface with light at the time of forward movement, and reflect the reflected light from the original surface with moving members 41 and 42.
Mirrors 41b, 41d and 42b,
From 42 c, it is guided to the photosensitive drum 51 of the image processing unit 5 through the lens 43 and the mirror 44, formed as an electrostatic latent image, developed by the developing device 52, and The image developed by the developing device is transferred, and the image on the paper is fixed by the fixing device 7, discharged to the paper receiver 62, and the image on the document is copied.

The original scanning device 4 includes a lamp 41 serving as a light source.
b, a mirror 4 for irradiating the light from the lamp 41b onto the document surface
1c and the reflected light from the original to the second scanning unit 42
The first mirror 41d provided with the mirror 41d for guiding in the direction of the second mirror 42b.
A scanning unit 41 and mirrors 42b and 4 for guiding the light from the first scanning unit 41 toward the lens 43;
2c comprises a second scanning unit 42 provided. The scanning units 41 and 42 are movably mounted on the guide rail 12 and the guide bar 11. The scanning units 41 and 42 are provided with rollers 25 and 26 for moving smoothly on the guide rail 12. I have.
The scanning unit is wound around the gear 10 by the rotation of the servomotor 120, and reciprocates by the wire 9 stretched by the pulleys 11 and 12. The wire 9 is fixed by the stopper 13 on the first scanning unit 41 and the pulley 13 on the second scanning unit 42
And follow the movement of the first scanning unit 41 to move the second scanning unit 42 to the first scanning unit 4.
The distance of the optical path system is not changed by moving by half of the moving distance of 1. When the rotation of the motor 120 is in the A direction, the wire 9 is pulled in the A ′ direction, and the scanning units 41 and 42 move in the forward movement A ″ direction,
Conversely, when the motor 120 rotates in the B direction, it moves in the backward movement B '' direction. In FIG. 1, the light guide path is indicated by a dashed line, and the scanning units 41 and 42 are indicated by a dashed line.
Showed the move.

As shown in FIG. 3, the control system controls the operation according to a program stored in a memory (not shown).
PU 101, oscillator 103 oscillating at the frequency of the natural vibration of the scanning unit described later, monostable multivibrator 102, counter 104, D / A converter 105,
And NAND circuits 106 and 107, NOT circuit 1
08 and 109.

The operation of the control system will be described. FIG. 4 shows a timing chart of each signal. CPU
101 controls the servomotor 120 in accordance with a scanning request from a host CPU of a copying machine (not shown) to reciprocate the scanning unit. For this purpose, the CPU 101
Indicates that the servo motor 120 is turned on (ON).
/ Off (OFF), direction of rotation, stop (brake)
A signal such as an instruction is sent, a speed command voltage is generated via the D / A converter 105, and scanning is started.

The servo motor 120 is provided with an encoder. The encoder signal is counted by the counter 104, and the current position of the scanning unit can be monitored. It is detected that the position has been reached.

When it is detected that the scanning by the forward movement has been completed and the CPU 101 has reached the first predetermined position, the CPU 101 performs an operation of returning the scanning unit to the home position and returning the scanning unit to the home position. And the second near the home position
Is detected, the motor is instructed to perform reverse driving, the scanning unit is forcibly braked, and the scanning unit is further moved to come to the third predetermined position near the home position. When the detection is made, the reverse driving force of the motor is turned off, the mode is switched to the regenerative brake, and the scanning unit is stopped. At this time, vibration is generated as described later in connection with switching to the regenerative brake.

The ON / OFF signal of the motor is transmitted to a NOT circuit 10
9 is supplied to the transmitter 103 via the CPU 10
At the same time, the motor-off command from 1, ie, the regenerative braking is applied, and the reset of the transmitter 103 is released to start the oscillation.

When the reset is released, the oscillator 103 outputs an oscillation signal having the same frequency as the fundamental frequency of the natural vibration of the scanning unit, which will be described later, is input to the monostable multivibrator 102, and outputs the natural vibration of the scanning unit, which will be described later. A pulse having the same cycle as the cycle T is generated.

When the scanning unit detects that the home position has been reached, a home detection signal is input to the NAND circuit 106 as shown in FIG.
When a scan request is issued from the host CPU for re-scanning, an interrupt is issued to the CPU 101 in synchronization with the pulse output from the monostable multivibrator 102. When this interrupt occurs,
U101 outputs a motor-on command, and the forward movement for scanning is started. That is, the forward movement is started at a timing when a time elapses nT, which is a natural number times the natural oscillation period T of the scanning unit. At this time, vibration occurs with the start of the motor, and the vibration caused by the start has an opposite phase to the vibration generated at the time of the backward movement, as described later.
Vibration is canceled and scanning without vibration is performed.

Here, the vibration of the scanning unit in the original scanning operation will be described with reference to FIG. FIG.
It is a figure which shows the speed pattern of a scanning unit.
Is the forward movement direction, and-is the backward movement direction.

First, as shown in the figure, when the scanning unit starts to move forward for reading a document as shown in the figure, the scanning unit is slightly vibrated by this start and the speed is increased to the scanning speed. When the scanning unit reaches the end point (first predetermined position) after the operation is performed at the scanning speed, the speed in the reverse direction increases for the backward movement. Then, the carriage is moved backward until it reaches the constant speed and reaches the second predetermined position. When the arrival at the second predetermined position is detected, the motor is reversely driven, and the scanning unit is forcibly braked. As a result, the speed is reduced, and when the third predetermined position is reached, the driving force of the motor is turned off, the regenerative brake is switched to stop the scanning unit. When the regenerative brake is applied, another vibration occurs.

The vibrations that most affect the original scanning device are the vibrations at the start of the start of the scanning unit (scanning means) and the vibrations at the start of the operation of the regenerative brake. In particular, when scanning is performed continuously. In this case, the forward movement starts with the vibration at the time of the backward movement, so that the speed increases while the scanning unit vibrates, and the scanning unit vibrates even while the original is being read at the constant speed of the scanning unit. This causes a problem in reading the original.

The vibration generated at the time of the backward movement and the vibration generated at the time of the start of the forward movement are natural vibrations which can be mechanically configured, and their fundamental frequencies have the same period as shown in the following equation (1). Vibration. Further, the vibration at the time of the backward movement and the vibration at the time of the start have amplitudes of rising phases opposite to each other.

[0038]

(Equation 1)

In the equation (1), JM is the motor inertia moment, JL is the load inertia moment, K is the transmission system torsional rigidity, and the motor inertia moment, the load inertia moment and the transmission system torsional rigidity have little variation. ,
Since there is almost no change with time, the frequency of the natural vibration is always constant for the same model.

Therefore, if the timing from the stop of the scanning unit to the start of the next forward movement is set so that the vibration in the opposite phase to the vibration of the scanning unit is applied, the vibration at the time of the backward movement is canceled by the vibration at the start. It will be. For example, as shown in FIG. 6, by setting the time from the reverse drive of the motor in reverse movement to the drive on for starting the forward movement of re-scanning to be a natural number times the cycle of the natural vibration, the time of the backward movement can be reduced. The vibration at the time of starting is applied in an opposite phase to the vibration, so that the vibration is canceled. Conversely, as shown in FIG. 7, when the time from the reverse drive OFF to the drive ON is set to a natural number multiple of half of the period T of the natural vibration, the vibration at the time of the starting movement is smaller than the vibration at the time of the backward movement. Have the same phase, and the vibrations are superimposed and become larger.

In the present invention, focusing on this point, as described above, the time from the start of braking during the backward movement to the start of rescanning is set at a timing that is a natural number times nT of the natural vibration period T. It is controlled to be performed.

Embodiment 2 An embodiment to which the second invention is applied will be described. In the second embodiment, the mechanical configuration of the document scanning device is the same as that of the first embodiment, and the description is omitted.

FIG. 8 is a block diagram of a control system according to the second embodiment.
1, monostable multivibrators 110 and 1
11, counter 104, D / A converter 105, and N
AND circuits 106 and 114, NOT circuits 108, 1
13 and 115, and an XOR circuit 112.

The operation of the control system will be described. FIG. 9 shows a timing chart of each signal.

The CPU 101 operates according to a scanning request from a host CPU of a copying machine (not shown).
20 is controlled to reciprocate the scanning unit.

To this end, the CPU 101 controls the servo motor 120 to turn on / off (OF) the motor.
F), a signal such as a rotation direction instruction or a stop (brake) instruction is sent, a speed command voltage is generated via the D / A converter 105, and scanning is started.

The servo motor 120 is provided with an encoder. The encoder signal is counted by a counter 104, and the current position of the scanning unit can be monitored. It is detected that the position has been reached.

When the scanning unit is at the home position, the CPU 101 outputs a motor-on signal for driving the motor in accordance with a scanning request from a host CPU of a copying machine (not shown). The motor-on signal is
NAND circuit 114 and NOT circuit 1
15 and input to the two monostable multivibrators 110 and 111. Of the two monostable multivibrators, the monostable multivibrator 110 is a half cycle (1) of the cycle T of the natural vibration of the scanning unit described in the first embodiment.
/ 2T) is generated by the input of the motor-on signal, and the monostable multivibrator 111 outputs a pulse T having a period shorter than 1 / 2T.
Occurs (発 生 T> T ′).

The outputs from these two monostable multivibrators 110 and 111 are supplied to an XOR circuit 112.
And a TON circuit 113, and is input to the NAND circuit 114 together with the motor-on signal.

As shown in the timing chart of FIG. 9, the motor 120 receives the motor-on signal from the CPU 101 and the one from the monostable multivibrator 110.
It operates when there is a signal having a length of / 2T and a signal having a length of T 'from the monostable multivibrator 111, and drives the scanning unit.

After T 'seconds, the signal of the monostable multivibrator 111 disappears, and the driving of the motor stops. That is, when the motor is turned on by the CPU 101, the scanning unit moves a minute distance. Thereafter, when the signal from the monostable multivibrator 110 having a length of 1 / 2T cycle disappears and only the motor-on signal is turned on, the motor 120 starts driving again, the scanning unit starts operating, and the scanning starts. Outbound movement is performed.

By these operations, the scanning unit
When a scanning request is made, first, a movement is made for a minute distance, and vibration is generated by this minute distance movement. Then, vibration is generated again at the time of starting for the forward movement. By setting the timing from the minute distance movement to the start of the forward movement as the timing of a half cycle of the natural vibration cycle T as described above, the phases of the two vibrations are opposite to each other, thus canceling each other. Will be done.

FIG. 10 shows the state of this vibration. The dotted line indicates the case where the vibration generated by the movement of a minute distance continues, and the dashed line indicates the case where the vibration generated by the start of the forward movement continues. The solid line is a combination of the vibration caused by the minute movement and the vibration caused by the start of the forward movement, and is the actual vibration state of the scanning unit in the second embodiment. As can be seen from the figure, the vibration is reduced in the actual operation (solid line).

In the second embodiment, the pulses from the monostable multivibrators 110 and 111 are set such that one pulse has a length of 1 / 2T and T ', respectively, so that the natural vibration from the start of the minute movement. The forward movement is started after a lapse of half the period T of the period T. However, in particular, the forward movement is not limited to the length of 1 / 2T as described above. If the forward movement is started after several times the length (n + ／) T, the timing at which the vibration at the time of the minute movement and the vibration at the start of the forward movement have opposite phases is completely different from the second embodiment. Similarly, when starting the forward movement, the vibration can be suppressed.

Also, in the second embodiment, the forward movement is set to the same direction as the minute distance movement. However, since this minute movement is to generate vibrations before the start of the forward movement, The movement is not limited to the same direction, and may be movement in the opposite direction. However, in this case, the interval from the minute movement to the start of the forward movement is set to a time when a time that is a natural number multiple of the natural vibration period elapses. This is because when the moving direction of the scanning unit is reversed, the rising phases of the vibrations are opposite to each other. The apparatus configuration for this is the same as that of the second embodiment, but the length of the pulse output from the monostable multivibrator 110 may be set to the same T as the natural vibration.

The configuration of the control system according to the first and second embodiments is merely an example for embodying the present invention, and the present invention is not limited to such a configuration. Instead of the monostable multivibrator used in the first and second embodiments, a signal from a CPU or other timer or a transmitter in the control system is divided and used so as to match the period T of the natural vibration. Further, the configuration of the control system can be simplified.

The document scanning device of the present invention can be used not only in a copying machine but also in an image scanner or the like, and the scanning unit itself is not limited to a device in which a mirror is movable as in the first and second embodiments. Instead, the present invention can also be applied to a contact type original scanning device in which a CCD line sensor or the like directly reads the original surface. In this case, the mechanical mechanism of the original scanning device generally includes a contact type CCD line in the scanning unit 41 in the above embodiment. There is a sensor and a light source, and the reflected light from the light source is read directly by a CCD line sensor. Of course, even when the mirror is moved by scanning, the reflected light from the original is not limited to the one that directly guides the reflected light from the original to the drum for forming a latent image. The present invention can also be suitably used in a copying machine or an image scanner of a type that reads using a line sensor).

[0058]

According to the present invention as described above, the following effects can be obtained. First, according to according to the first aspect of the present invention according to claim 1 to 3, the vibration generated with the braking start during backward movement in successive scans, the starting timing of the re-scan, such as vibrations of opposite phase is applied, For example, when a natural number multiple of the period of the vibration inherent to the scanning means has elapsed, the vibration at the time of the backward movement is offset by the vibration generated at the start of the movement. Without increasing the weight of the mechanical mechanism and the scanning means itself,
Scanning movement for stable document reading is performed.

[0059] Then, according to the second invention of claim 4-7, when the scanning means starts the start-up from rest,
By moving a small distance in advance and generating vibration, and starting scanning movement at a timing opposite to this vibration,
The mutual vibrations are canceled, and a special mechanical mechanism for canceling the vibration by the scanning means or the like, and the scanning movement for stable reading of the original is performed without increasing the weight of the scanning means itself.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an electrophotographic copying machine using a document scanning apparatus to which the present invention is applied.

FIG. 2 is a perspective view showing a mechanical mechanism of the document scanning device to which the present invention is applied.

FIG. 3 is a block diagram of a control system according to a first embodiment to which the present invention is applied.

FIG. 4 is a timing chart of Example 1 to which the present invention is applied.

FIG. 5 is a diagram illustrating a speed pattern of a scanning unit.

FIG. 6 is a diagram for explaining vibration of a scanning unit.

FIG. 7 is a drawing for explaining vibration of a scanning unit.

FIG. 8 is a block diagram of a control system according to a second embodiment to which the present invention is applied.

FIG. 9 is a timing chart of Example 2 to which the present invention is applied.

FIG. 10 is a diagram for explaining vibration of a scanning unit.

FIG. 11 is a perspective view showing a mechanical mechanism of a conventional document scanning device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Copy machine, 4 ... Document scanning device, 41, 42 ... Scanning unit (moving member), 101 ... CPU, 102, 110, 111 ... Monostable multivibrator, 103 ... Transmitter, 104 ... Counter, 105 ... D / A converter, 106, 106, 107 ... NAND circuit, 108, 109, 113 ... NOT circuit, 112 ... XOR circuit, 120 ... motor.

Claims (7)

(57) [Claims] 1. A document scanning apparatus in which scanning means scans a document image by reciprocating the scanning means, wherein the scanning is performed at a timing at which a vibration having a phase opposite to a vibration generated with a braking operation at the time of the backward movement of the scanning means is generated. A document scanning device having control means for instructing a start of scanning forward movement of the means. 2. The document scanning device according to claim 1, wherein the timing is a time when a time which is a natural number times a period of a vibration generated by braking of the scanning unit has elapsed. 3. The apparatus according to claim 2 , wherein said control means stops said scanning means.
The same frequency as the fundamental frequency of the natural vibration of the scanning means
Oscillator that outputs an oscillation signal of the oscillator, and an oscillation signal of the oscillator.
And the same period as the period of the natural vibration of the scanning means
Monostable multivibrator that generates multiple pulses
Has the door, this to forward movement of the scanning means in synchronization with the pulse
2. The document scanning device according to claim 1, wherein: 4. A document scanning apparatus in which a scanning unit moves for scanning a document image, wherein the scanning unit is moved by a small distance and stopped at the start of the scanning movement of the scanning unit. An original scanning apparatus, comprising: a control unit that instructs a start of scanning movement of the scanning unit at a timing when a vibration having a phase opposite to the vibration occurs. 5. The minute distance movement is in the same direction as the scanning movement direction of the scanning unit, and the timing is a time when a time which is a natural number times a half of a period of a vibration generated by the minute distance movement elapses. 5. The document scanning device according to claim 4 , wherein: 6. The method according to claim 6, wherein the minute distance movement is in a direction opposite to a scanning movement direction of the scanning unit, and the timing is a time when a natural number times a period of a vibration generated by the minute distance movement elapses. The document scanning device according to claim 4 , wherein 7. The control means according to claim 1 , wherein
Monosutebu for generating a pulse of 1/2 laps phase of the cycle of movement
Multivibrator and a cycle shorter than the half cycle
Monostable multivibrator that generates multiple pulses
And the pulse having a cycle shorter than the half cycle is used for the minute distance.
Move away and synchronize with the pulse of the half cycle.
5. The apparatus according to claim 4, wherein the scanning unit is moved forward.
The document scanning device according to 1.