JPH05300333A - Original reader and scanning moving device - Google Patents

Abstract

PURPOSE:To obtain the original reader and the scanning moving device with a wide variable magnification range in which a picture is read with high quality by providing a variable speed means revising a scanning speed of a scanning unit to a drive transmission means. CONSTITUTION:The device is provided with a CCD read sensor 2, guide rails 3A, 3B, a main scanning board 1, a subscanning board 4, subscanning board rails 5A, 5B and a main scanning drive system 7 or the like. Then, a drive source moves a scanning unit via a drive transmission means and a read means is used to read a picture at a prescribed scanning speed during the forward drive and the scanning speed is properly changed by the variable speed means provided in the drive transmission means and scanning is implemented for a region of the rotation in which vibration of the drive source hardly takes place, then it is prevented that the vibration is delivered to the scanning unit, adverse effect is given on the reproduction performance of a read position to lose the picture quality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document reading device and a scanning moving device, and more particularly to a document reading device and a scanning moving device having a scanning section such as a reading optical system driven by a stepping motor.

[0002]

2. Description of the Related Art CC is conventionally used in a scanning optical system scanning unit.
A document reading device including a D image sensor, which reads an image from a document by scanning the image, converts the image into an electric signal, and outputs the signal to a recording device such as a copying machine or a printer, has been widely used. By the way, in such a document reading apparatus, for example, FIG.
As shown in FIG. 1, a scanning unit (not shown) having a CCD sensor 200 having a short reading length of about 16 mm is scanned in the main scanning direction indicated by an arrow Y on the original 201 to read an image corresponding to the width. , Each time the main scanning is completed, the scanning unit is moved in the sub scanning direction (indicated by arrow X).
, Where the main scanning reading is performed again,
An image is read from the entire surface of the original 201 by repeating the above.

[0003]

By the way, regarding the reading of the original 201 in the conventional example,
It is necessary to accurately connect the respective areas to be read when the CCD sensor 200, which is the reading means, is scanned in the arrow Y direction in the sub-scanning direction. For this reason, conventionally, in this type of apparatus, the reading means and the like have been arranged so as to be driven by a stepping motor which is easy to control and to perform accurate scanning.

However, the stepping motor has a narrow range of speed in which it smoothly rotates due to its characteristics, and therefore, when performing variable-magnification reading such as enlargement or reduction, the scanning speed cannot be changed greatly, and therefore, the reading speed is increased. However, there is a problem that the variable magnification range cannot be wide.

That is, the vibration due to the stepwise rotational movement of the motor generated at the low speed rotation is particularly severe in the stepping motor, and the vibration is transmitted to the reading means through the drive transmission means such as a wire. The reproducibility is deteriorated, and the scanning speed is changed, which causes a reduction in reading accuracy.

Further, when the reading means is scanned at a steady speed, the transient position vibration deteriorates the read position accuracy during acceleration from the stopped state to the steady speed or during transition from the accelerated state to the steady speed. Therefore, in order to prevent such an adverse effect due to the transient vibration, it is necessary to start the reading after the vibration is sufficiently attenuated, which causes a problem that the apparatus becomes large.

The object of the present invention is to pay attention to such a conventional problem, and it is possible to smoothly move a scanning unit such as a reading unit even when a motor which easily causes vibration is used. Its variable magnification range is wide, and
An object of the present invention is to provide a document reading device and a scanning moving device capable of reading a high quality image.

[0008]

In order to achieve such an object, the document reading apparatus of the present invention causes a scanning unit to reciprocate by a drive source via a drive transmission means, and at a predetermined speed during the forward movement. In the document reading apparatus in which the document reading operation is performed by the reading unit provided in the scanning unit while scanning, the drive transmission unit is provided with a speed changing unit for changing the scanning speed of the scanning unit. ..

Further, the scanning moving apparatus of the present invention is a scanning moving apparatus in which the driving source reciprocally scans the scanning unit along a guide rail at a predetermined speed via a drive transmission means. It is characterized in that a sliding member for generating a frictional load with the guide rail is provided.

[0010]

According to the document reading apparatus of the present invention, the scanning unit is moved by the drive source through the drive transmission unit, and the reading unit performs reading at a predetermined scanning speed during the forward movement. Since it is possible to change the scanning speed appropriately by the provided speed changing means, the vibration is transmitted to the scanning unit by scanning in the rotation area where the vibration of the drive source is unlikely to occur, and the reading position is reproduced. It is possible to prevent the image quality from being adversely affected and the image quality from being deteriorated.

Further, according to the scanning movement apparatus of the present invention, the scanning unit is provided with the sliding member for generating the frictional load between the scanning unit and the guide rail, and the load is applied during the forward scanning and the backward scanning of the scanning unit. Therefore, it is possible to contribute to the position reproducibility of the scanning unit and prevent the fluctuation of the scanning speed by rapidly attenuating the transient vibration that occurs in the initial scanning of the scanning unit or the like.

[0012]

Embodiments of the present invention will now be described in detail and specifically with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. here,
Reference numeral 1 denotes a main scanning table on which a reading optical system including a CCD reading sensor 2 is mounted, and main scanning driving is performed in the directions of arrows A and B along guide rails 3A and 3B. Reference numeral 4 movably supports the main scanning table 1. Together with this, the sub-scanning base moves along the sub-scanning rails 5A and 5B. 6A and 6B are side plates provided at both ends of the sub-scanning base 4 and supporting the ends of the guide rails 3A and 3B, 7 is a main scanning drive system attached to the side plate 6A, and 8 is connected to the main scanning base 1. It is a wire which is stretched between the pulleys 9A and 9B and driven by the motor 10 of the main scanning drive system 7 .

Both ends of the sub-scanning rails 5A and 5B for guiding the sub-scanning table 4 are supported by a document reading apparatus main body (not shown). 11 is a motor for driving the sub-scanning table 4 , 12
Is a drive shaft driven by the motor 11, 13 is a pulley thereof, 14 is a drive belt stretched between the pulley 11A of the motor 11 and the pulley 13, and 15A and 15B are sealed at the both ends of the sub-scanning base 4. Endless wire, which is stopped and driven by the motor 11 via the drive shaft 12, 16
A is a deflection pulley for wire 15A, and wire 15B
Similarly, a deflecting pulley (not shown) is also provided on this side.

In the image reading apparatus constructed as described above, the reading sensor 2 reads a document placed on a document table (not shown) while the main scanning table 1 is moving in the main scanning direction indicated by the arrow A. , The main scanning table 1 is indicated by the arrow B for each main scanning.
The sub-scanning table 4 is returned to the home position (hereinafter referred to as HP) by the movement in the direction, and the sub-scanning table driving motor 11 sub-scans the sub-scanning table 4 in the direction of the arrow C by a distance corresponding to the reading width. Here, the arrow D indicates the direction in which the sub-scanning table 4 is returned when the reading of one document is completed.

Next, the details of the main scanning drive system 7 having means for transmitting the driving force will be described with reference to FIG.

Here, the motor 10 is provided with pulleys 21A and 21B at both ends thereof. Reference numeral 22 is an electromagnetic clutch, and 23 is a pulley coaxial with the electromagnetic clutch 22. Further, 24 is a motor pulley 21B and a pulley 23.
It is a belt stretched between and. Similarly, 25 is an electromagnetic clutch having a pulley 25A at one end, 26 is a belt stretched between the pulley 21A and the pulley 25A, and 2 is a belt.
Reference numeral 7 is an idler for adjusting the tension of the belt 26. Further, 28 is the electromagnetic clutches 22 and 25.
Is a drive shaft provided with a main scanning table at one end
1 for reciprocating the wire 8 drive pulley 9B
Are provided integrally.

Here, in the drive system consisting of the pulley 21B, the belt 24 and the pulley 23, the motor 10 and the drive shaft 28
So that they rotate at a constant speed, and in the drive system including the pulley 21A, the belt 26, and the pulley 25A, the motor 1
The drive shaft 28 is configured as a reduction system in which the rotation is slower with respect to 0 rotation, and the reduction ratio is set to about 3 in the present embodiment. During main scanning, only one of the electromagnetic clutches 22 and 25 is selectively energized to select either the constant speed system or the deceleration system. It should be noted that this selection is determined according to the reading magnification, the scanning direction, the reading sequence, etc., as described later.

In the case of the present embodiment, the influence of vibration occurs when the drive frequency of the motor 10 is 500 pps or less. Therefore, the drive system is switched from the constant velocity system to the reduction system when the drive frequency is less than the drive frequency. As a result, a highly accurate read image could be obtained at all times.

Further, in the case of this example, as described above,
Although the reduction ratio between the reduction system and the constant velocity system is set to about 3, it is not limited to this and may be appropriately selected from the scanning speed and the driving frequency of the motor.

Next, the structure of the main scanning table 1 will be described in detail with reference to FIGS.

Reference numeral 31 denotes an illumination system including a lamp for illuminating a document, a mirror (not shown), and the like, and 32 denotes a projection lens for projecting an image of the document illuminated by the illumination system onto the CCD sensor 2 by the projection lens 32. The projected original image is CC
The D (reading) sensor 2 sequentially converts the electric signals.
Further, 34 is a shield case that covers a driver substrate (not shown) for driving the CCD sensor, 35 is a detection piece for HP detection provided from the main scanning table housing 1A, and 36 is arranged on the sub scanning table side. A photo interrupter for HP detection,
This is for detecting HP in the main scanning direction. Reference numeral 37 is a fan for cooling the illumination system 31, 38 is a cover having a deflecting plate 38A for deflecting the cooling air from the fan 37 toward the illumination system 31 and an unillustrated platen glass, and these are fans. It is fixed together with 37 on the main scanning stand housing 1A.

Further, as shown in FIG. 4, the main scanning table 1 is provided with bearings 41A and 41B provided on the casing 1A and a bearing 41C provided on the urging unit 42 to one guide rail 3B, and with a bearing 41D. It is held movably in the main scanning direction with respect to the other rail 3A.

Further, as shown in FIG. 5, one end of the wire 8 is attached to a hook 43 formed in a part of the casing 1A by a spring 44.
And the other end of the wire 8 is
It is fixed to the through a cushioning member 46. The cushioning member 46 is formed of an elastic body such as rubber, and the main scanning table 1 is adversely affected by vibrations generated when the motor 10 of the drive system 7 rotates during the main scanning and swaying of the wire 8. The main scanning table 1 is smoothly reciprocated.

Next, the details of the urging unit 42 will be described with reference to FIG.

Here, 51 is a base member fixed to the main scanning stand housing 1A, 52 is an arm member having a roller 53 at one end and rotatably attached to the base member 51 by a support pin 54. The spring 55 urges the roller 53 at the tip thereof to be biased toward the rail 3B. Further, 56 has a roller 57 at one end, and a support pin 58
Is an arm member rotatably attached to the base member 51, and is biased by a spring 59 so as to bias the roller 57 toward the rail 3B.

Further, 60 is an arm member which has a pad 61 at one end and is rotatably attached to the base member 51 by a support pin 62, and is attached by a spring 63 so that the pad 61 is biased toward the rail 3B. It is energized. Here, the pad 61 gives an appropriate frictional load to the main scanning table 1 by contacting with the rail 3B, and the shock vibration accompanying the acceleration during scanning of the main scanning table 1 is generated between the pad 61 and the rail 3B. Can be attenuated by friction.

FIG. 7 shows the relationship between the rail 3B and the arm 60. Now, when the main scanning table 1 is scanned in the image reading direction (the direction of arrow A in the figure), the pad 61 and the rail 3B are moved in this way.
_A frictional force F _A is generated between the pad 61 and the rail 3B as a result of the frictional force F _A urging the arm 60 in the counterclockwise direction. Let On the other hand, when the main scanning table 1 is scanned in the image reading direction and then scanned in the return direction (the direction of arrow B in the drawing), a frictional force F _B is generated between the pad 61 and the rail 3B in the direction shown in the drawing. Since the frictional force F _B urges the arm 60 in the clockwise direction, the braking force generated between the pad 61 and the rail 3B is weakened. That is, the frictional force acts strongly during the scanning in the reading direction where quick damping of the vibration of the main scanning table 1 is required, and the frictional force acting as a load is weakened during the scanning in the returning direction where quick scanning is required.

FIG. 8 shows the configuration of the circuit according to the present invention. 1
Reference numeral 01 is a CCD driver for driving the CCD sensor 2 provided on the main scanning table 1 , and 103 is an image processing unit for performing the following processing on the output signal of the sensor 2. The image processing unit 103 is based on the information stored in the amplifier unit 104 for amplifying the output of the CCD sensor 2, the A / D converter 105 for sequentially A / D converting the output signal amplified by the amplifier unit 104, and the information stored in the memory 106. A shading correction unit 107 that corrects illumination unevenness and sensor bit unevenness, an input masking unit 108 that performs color correction by performing a 3 × 3 matrix operation on an input signal, a Log conversion unit 109 that performs gradation conversion, an edge It comprises a processing unit 110 for performing an enhanced masking UCR process, and a main-scanning variable-magnification interpolating unit 111 for performing an interpolation process at the time of variable-magnification reading of reduction or enlargement.

A CPU 112 has a RAM and a ROM, and controls the CCD driver 101, the image processing unit 103, and an I / O unit 113 described later. An I / O 113 manages information I / O based on the CPU 112.
Reference numeral 114 denotes an O unit, 114 is a controller for driving and controlling the main scanning motor 10 and the sub-scanning motor 11, 117 is clutch switching means for switching the electromagnetic clutches 22 and 25 of the drive system 7 ,
Reference numeral 118 is an HP for detecting the home position of main and sub-scanning.
A sensor 119 is an operation unit, 120 is an editor for inputting an area designation, and 121 is a CVR power source for controlling lighting of the lamp 122 of the illumination system 31.

Next, a typical reading sequence of the image reading apparatus according to the present invention will be described with reference to the flowchart of FIG.

First, when the reading start key is depressed, the constant velocity clutch 22 is energized in step S1, and the main scanning drive system 7 selects the constant velocity system. Thus, the main scanning motor 10 drives the main scanning table 1 in the direction of arrow B in FIG. 1, the sub scanning motor 11 drives the sub scanning table 4 in the direction of arrow D, and the HP detection operation is performed in step S2.
Initial positioning of the main scanning table 1 and the sub scanning table 4 is performed. The constant speed system is selected during the HP detection operation in order to shorten the time required for HP detection.

Next, at this position, the standard white plate positioned on the platen glass (not shown) is read, the lighting voltage of the lamp 122 and the amplifier gain are determined in step S3, and the read output is further stored as uneven information in the memory. 10
The shading correction stored in 6 is performed. Then, in step S4, for example, it is determined whether or not the minimum output value is less than or equal to a predetermined value with respect to the unevenness of the read output. And further reading magnification in step S6 is equal to or less than a predetermined value, in the case of less than the predetermined value to the scanned original reading operation in the reading direction of the main scanning stage 1 directly proceeds to step S7.

After the completion of reading one line by the main scanning, the process proceeds to step S8, the main scanning table 1 is returned to the start position, and
In step S9, the sub scanning table 4 is moved by a predetermined sheet feed amount. In step S10, it is determined whether or not the operations from steps S7 to S9 have been repeated a predetermined number of times for one page. After the predetermined number of times of reading, the process proceeds to step S11, in which the main scanning table 1 and the sub-scanning table 4 are set. After returning to the HP position, a series of reading operation is completed.

Furthermore, if the reading magnification is equal to or larger than the predetermined magnification in step S6, the flow branches to step S12, and the main scanning drive system 7 is made to select a reduction system by branching to the deceleration clutch 25 side. ..

Thus, the process proceeds to step S13 and the main scanning table
1 is scanned in the scanning direction to scan the original, and after scanning one line, the clutch 22 is switched to the constant speed clutch 22 in step S14.
In step S15, the main scanning table 1 is returned to HP, and in the next step S16, the sub scanning table 4 is moved by a predetermined sheet feed amount. It is determined whether or not the operation from steps S12 to S16 has been repeated a predetermined number of times in step S17, the document is read a predetermined number of times, and the operation is completed. After that, the process returns to step S11 and the main scanning table 1 and the sub-scanning table 4 are executed. Is returned to the HP position and a series of reading operation is completed.

When the reading magnification is equal to or greater than a predetermined value, the deceleration clutch 25 is switched to be energized for scanning in the reading direction, and the deceleration system is selected as the main scanning drive system 7 because deceleration is performed. Thus, by increasing the drive frequency of the stepping motor 10 in the main scanning drive system 7 , smooth rotation of the motor 10 can be obtained.

When the main scanning table 1 is returned to the starting position, the constant speed system is selected in order to increase the scanning speed of the main scanning table 1 and shorten the reading time. Furthermore, when switching the drive system 7 in steps S12 and S14 respectively, with the motor 10 completely stopped, the clutch already energized by that time is left as it is and the clutch not energized is energized. However, after that, it is desirable that the sequence in which the energization of the clutch that has been in the energized state is cut off. Thus since the one clutch or the drive system 7 Izure always at least is energized drive system 7
Since the main scanning stand 1 and the main scanning stand 1 are always integrated,
The position reproducibility of 1 is guaranteed, and the reading accuracy is not adversely affected.

FIG. 10 shows the construction of a biasing unit 42 according to another embodiment of the present invention. In this example, in the urging unit 42, the arm 60 including the pad 61 is formed in an L shape, and the solenoid 71 is connected to one end of the arm 60 to support the solenoid 71 on the housing 1A side and the pad 61 is generated by an electric signal. The contact state between the rail and the rail 3B is controlled by switching between contact and non-contact. Note that (A) shows a state in which the pad 61 is biased to the rail 3B, and (B) shows a non-contact state.

According to the present embodiment, the solenoid 71 is not energized during scanning in the reading direction of the main scanning table 1 , that is, scanning in which quick vibration damping is required, and the pad 61 and rail 3 are not energized.
Although a frictional force is generated between the pad B and the roller B, the solenoid 71 is energized to separate the pad 61 from the rail 3B at the time of scanning in the return direction so that the frictional force is not generated in the non-contact state. Further, according to this example, it is possible to energize the solenoid 71 and prevent the frictional force from being generated even at the time of reading at a high magnification at a low scanning speed with a low transient vibration.

With this structure, it is possible to generate a frictional force only during scanning in which vibration is a concern, and it is possible to improve the durability of the pad 61.

In each of the embodiments described above, the scanning unit of the document reading apparatus has been described, but the present invention is not limited to this, and it is also applicable to the scanning unit of a printer, for example. Needless to say.

Furthermore, in the above embodiment, the switching by the main scanning drive system 7 is the constant speed system or the deceleration system.
The present invention is not limited to this, and a speed increasing system, a constant speed system, a speed reducing system, or the like can be configured to appropriately select the main scanning speed from the drive frequency of the motor 10 according to the reading magnification. In addition, the original is CC-scanned by an optical system that scans a mirror, etc.
Needless to say, the same effect can be obtained even if the invention is applied to a mirror scanning drive system in a reading device that projects on a D sensor.

[0044]

As described above, according to the present invention,
In the original reading device in which the scanning unit is reciprocally moved by the drive source via the drive transmission unit, and the original reading operation is performed by the reading unit provided in the scanning unit while scanning at a predetermined speed during the forward movement. Since the transmission means is provided with the speed changing means for changing the scanning speed of the scanning unit, the main scanning unit can smoothly travel at a low speed even when a motor having a lot of vibration such as a stepping motor is used. As a result, even if the variable magnification range at the time of reading is expanded, the reading accuracy does not deteriorate.
Further, since the vibration of the main scanning unit can be suppressed to an extremely low level, high reading accuracy can be obtained even when reading is performed by repeating scanning.

Further, since a simple mechanism such as an electromagnetic clutch is adopted as a means for changing the gear ratio and adjustment is unnecessary, a large increase in cost will not occur.

Still further, according to the present invention, in the scanning moving device in which the scanning unit is reciprocally scanned along the guide rail at a predetermined speed by the drive source via the drive transmission means, the scanning unit is provided with the guide. Since a sliding member that creates a frictional load with the rail is provided, transient vibrations of the traveling unit can be quickly attenuated, so high scanning accuracy can be obtained without increasing the size of the device. Is possible.

Further, since the frictional load generated between the guide rail and the guide rail can be changed depending on the scanning direction and the scanning speed, the durability of the sliding member can be improved and the driving motor of the main scanning unit can be downsized. It is also possible to plan.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration example of a main part of a document reading apparatus of the present invention.

FIG. 2 is a perspective view showing a configuration example of a scanning drive system according to the present invention.

FIG. 3 is a perspective view showing a configuration example of a main scanning table according to the present invention.

FIG. 4 is a front view of the main scanning table shown in FIG.

5 is a plan view of the main scanning table shown in FIG.

FIG. 6 is a plan view showing a configuration example of a biasing unit according to the present invention.

FIG. 7 is an explanatory diagram of an operation by the urging unit shown in FIG.

FIG. 8 is a block diagram showing a circuit configuration of a document reading apparatus according to the present invention.

FIG. 9 is a flowchart showing an example of a control operation procedure of the document reading apparatus according to the present invention.

FIG. 10 is an explanatory diagram showing the configuration of an urging unit according to another embodiment of the present invention together with the operation.

FIG. 11 is an explanatory diagram of a reading operation.

[Explanation of reference numerals] 1 main scanning table 2 CCD reading sensors 3A, 3B guide rail 4 sub-scanning table 10 main scanning system drive motor 11 sub-scanning table drive motor 21 motor 22, 25 clutch 24, 26 belt 28 drive shaft 31 illumination system 42 urging unit 51 base member 52, 56, 60 arm 53, 57 roller 54, 58, 62 support pin 55, 59, 63 spring 61 pad 71 solenoid

Claims (9)

[Claims] 1. A document reading operation in which a scanning unit is reciprocally moved by a driving source through a drive transmission unit, and scanning is performed at a predetermined speed during the forward movement, and a document reading operation is performed by a reading unit provided in the scanning unit. The apparatus according to claim 1, wherein the drive transmission means is provided with a speed changing means for changing a scanning speed of the scanning unit. 2. The shift means can be switched according to a moving speed of the scanning unit.
The document reading device according to item 1. 3. The document reading apparatus according to claim 1, wherein the speed change means can be switched according to a scanning speed of the scanning unit at the time of reading a document. 4. The speed change means has different speed ratios, and has a plurality of gear trains on a drive shaft driven by the drive source via a belt train and a plurality of clutches provided on the drive shaft. 4. The document reading device according to claim 1, wherein the document reading device is a document reading device. 5. The document reading device according to claim 4, wherein the plurality of clutches are electromagnetic clutches. 6. When the gear ratio is changed, one of the energized clutches remains energized to energize the other non-energized clutch, and then the one energized clutch is de-energized. The document reading apparatus according to claim 5, further comprising control means controlled as described above. 7. A scanning moving device configured to reciprocally scan a scanning unit along a guide rail at a predetermined speed by a drive source via a drive transmission means, wherein a friction load is applied to the scanning unit with the guide rail. A scanning movement device comprising a sliding member for causing the movement. 8. The scanning movement apparatus according to claim 7, wherein the frictional load generated by the sliding member changes between forward movement and backward movement of the scanning unit. 9. The scanning movement device according to claim 7, wherein the frictional load generated by the sliding member changes according to the scanning speed of the scanning unit.