JPH0756243A - Traveling body driving device - Google Patents

Abstract

PURPOSE:To provide a traveling body driving device of an image reader constituted so that a linear motor or an ultrasonic motor can be easily fitted to a first traveling body. CONSTITUTION:A movable back yoke 205 and a movable coil 206 are installed on the original side, that means, at the upper surface of the first traveling body 8. A driving magnet 207 and a fixed back yoke 310 are installed on an image reader main body 311 so that they face the coil 206, so as to form the air gap of the linear motor on the upper surface. Thus, the linear motor is easily fitted in the traveling body driving device where the linear motor is installed on the first traveling body 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling body drive device,
More specifically, the present invention relates to a traveling body driving device used in an image reading device that optically reads a document placed on a document table and obtains a document image.

[0002]

2. Description of the Related Art A first traveling body having a light source for reading an original placed on a document table and a second traveling body having a speed ratio of 1/2 of the first traveling body are the same sub-vehicle. An image reading apparatus that scans in the scanning direction to read an image described on the original document, collects the read image by a lens, and projects and forms the image on a light receiving device to obtain an original image is a factory, office, or the like. Widely used in. As a traveling body driving device for driving the first traveling body and the second traveling body in such an image reading apparatus, for example, it is proposed in Japanese Patent Laid-Open No. 23435/1993. In this traveling body drive device, wires are wound around one or both sides of the first and second traveling bodies that move in the same direction at a speed of 2 to 1, and one of the first and second traveling bodies is driven by a linear motor. However, the other traveling body is driven by the action of the wire and the moving pulley. According to this traveling body driving device, by using the linear motor, compared with the conventional method of driving the traveling body by linearly converting the power of the rotation motor by the rotation-linear conversion system including the gear and the wire system. ,
Since vibration due to the transmission / conversion system does not occur, highly accurate sub-scanning drive is possible.

In addition, in the unpublished application by the applicant, 2
In a traveling body driving device of an image reading apparatus that drives two traveling bodies at a speed of 2: 1 to read an original, a steel belt is wound around the wire instead of the wire, and the first or second
It has been proposed that either one of the running bodies is driven by a linear motor or an ultrasonic motor. According to this traveling body drive device, the precision of the sub-scanning drive can be improved. As described above, in the conventional traveling body drive device, the sub-scanning drive system is improved by using the linear motor and the ultrasonic motor.

[0004]

However, the specific configurations of these conventional traveling body drive devices are described only in detail only when the linear motor is attached to the second traveling body as an embodiment. However, the installation on the first traveling body is only described in the text. Therefore, the second
When the linear motor is attached to the first traveling body by the method of the embodiment in which the linear motor is attached to the traveling body, there is a problem that the mounting of the linear motor becomes complicated. Therefore,
A first object of the present invention is to provide a traveling body drive device capable of easily attaching a linear motor or an ultrasonic motor to the first traveling body. A second object is to prevent an adverse effect caused by sucking the magnetic material arranged around. Further, a third object is to prevent the traveling body from being adversely affected by the leakage magnetic flux and the like.

[0005]

According to a first aspect of the present invention, a first traveling body and a second traveling body that hold an optical element are provided.
In an image reading apparatus that directly drives a linear motor installed on the first traveling body and moves in the sub-scanning direction at a speed ratio of 2: 1 to read an image, a movable back yoke and a movable back yoke are provided on the upper surface of the first traveling body on the original side. The coil is installed, and the drive magnet and the fixed back yoke are installed in the image reading apparatus main body at a position facing the movable coil so that the air gap of the linear motor is formed above the coil, thereby achieving the first object. To do. According to a second aspect of the invention, in the traveling body drive apparatus according to the first aspect, the image reading device main body of the portion to which the drive magnet is attached or the entire image reading device main body is made of the same material as the fixed back yoke, and the fixed back yoke is omitted. Then, the first object is achieved. According to a third aspect of the invention, in the traveling body drive apparatus according to the first and second aspects, the entire first traveling body or only a portion to which the movable back yoke is attached is made of the same material as the movable back yoke, and the movable back yoke is omitted. To achieve the first object. According to a fourth aspect of the present invention, in the traveling body drive device according to the first to third aspects, between the fixed back yoke and the image reading device body, or between the movable back yoke and the first traveling body. A ferromagnetic material is installed on at least one side to achieve the second object. According to a fifth aspect of the present invention, in the traveling body drive apparatus according to the fourth aspect, an air gap is provided between at least one of the ferromagnetic body and the image reading device main body or the ferromagnetic first traveling body. It is provided to achieve the third object. In the invention according to claim 6, the first traveling body and the second traveling body which hold the optical element are
In an image reading device that directly drives a linear motor installed on the first traveling body and moves the image in the sub-scanning direction at a speed ratio of 2: 1 to read an image, an ultrasonic motor movable element is provided on the upper surface of the first traveling body, that is, on the document side. Is installed, and the ultrasonic motor stator is installed on the upper side of the image reading apparatus main body to achieve the first object.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a traveling body driving apparatus of the present invention will be described in detail below with reference to FIGS. FIG. 1 shows a schematic configuration of an optical system of an image reading device in which a traveling body drive device is used. The image original 0 placed on the contact glass 1 is illuminated by a halogen lamp 2 as a light source, the reflected light is reflected by the first mirror 3, the second mirror 4 and the third mirror 5, and is read by a lens 6, for example, a CCD. It is projected on the sensor 7. The image is read by the main scan by the CCD sensor self-scan,
In FIG. 1, the speed ratio of the first traveling body 8 on which the first mirror 3 and the halogen lamp 2 are installed and the second traveling body 302 on which the second and third mirrors are installed (not shown in FIG. 1) is 2: 1. By sub-scanning in the A direction, the entire area of the image original 0 can be read.

FIG. 2 shows the traveling body drive unit in this embodiment as seen from the air gap of the linear motor.
FIG. 3 shows the relative relationship between the first traveling body, the linear motor attached to the first traveling body, and the main body of the image reading apparatus. Further, FIG. 4 shows a side view of the linear motor portion, and FIG. 5 shows a driven method of the second traveling body. It is a thing.

In the first embodiment, the movable back yoke 205 and the movable coil 206 are installed on the upper surface of the first traveling member 8, that is, on the side of the original, and the drive magnet is formed so that the air gap of the linear motor is formed on the upper surface. The fixed back yoke 207 and the fixed back yoke 310 are installed in the image reading apparatus main body 311 at a position facing the movable coil 206. Accordingly, in the traveling body drive device that installs the linear motor on the first traveling body 8, the linear motor can be easily attached.

The specific structure will be described below.
The first traveling body 8 holding the light source 2 for reading the original and the reflection mirror 3 has two bearing portions 201A, 2A at one end.
01B, and one bearing portion 201C at the other end. The first traveling body 8 has two bearing portions 201.
A and 202B are fitted to the first guide shaft 202,
The bearing 201C at the other end is in contact with the second guide shaft 203. On the other hand, the second traveling body 302 has two bearings 204A, 204B and 204C, 204 at both ends, respectively.
Equipped with D. The bearings 204A and 204B are fitted on the first guide shaft 202, and the bearings 204C and 20B
4D is in contact with the second guide shaft 203.

A movable back yoke 205 for forming a magnetic circuit and a driving coil 206 are mounted on the upper surface of the first traveling body 8 in the vicinity of the bearing portion 201B via a coil substrate (not shown). As shown in FIG. 4, the movable back yoke 2 of the image reading apparatus main body 311.
A fixed back yoke 310 for forming a magnetic circuit, which is long in the sub-scanning direction, is fixed at a position facing 05. The fixed back yoke 310 includes a movable back yoke 20.
A magnet 207 in which the S poles and N poles of the surface are alternately arranged in the sub-scanning direction is attached while maintaining a constant air gap with the coil 206 of No. 5. The movable back yoke 205, the coil 206, and the fixed back yoke 310.
And the magnet 207 form a linear motor. In this configuration, when current is supplied to the driving coil 206 by the control circuit (not shown), the first traveling body 8 is sub-scanning driven by direct drive in the direction of arrow A in FIG.

In this embodiment, a multi-pole linear DC motor is taken as an example of the linear motor for directly driving the first traveling body 8. However, in the case of a linear motor,
For example, a single-pole linear DC motor (so-called voice coil type) or a linear pulse motor can also be used.

As shown in FIG. 2, a first belt 208 is hung on the outside of the first guide shaft 202 of the first traveling body 8,
A second belt 209 is hung on the outside of the second guide shaft 203 of the second traveling body 302. Since the method of hanging the belts and the operation of the belts are exactly the same, the first belt 208
5A and 5B are side views of the first belt 208, and the description will focus on the first belt 208. One end and the other end of the first belt 208 are connected to the image reading device main body 3 by the belt ends 20 and 20 '.
It is fixed at 11 different positions. This first
The belt 208 has two bearings 2 of the second traveling body 302.
04A, 204B (204C, 2 in the second belt 209)
04D), the pulleys 210A and 210B (210C and 210D in the second belt 209) supported by shafts 501A and 501B are wound around each half turn. In addition, the moving pulleys 210A and 210B (second belt 2
In 09, the first traveling body 8 is clamped by the first traveling body clamp 210D (the second belt 210E) on the first belt 208 (second belt 209) located in the intermediate portion between 210C and 210D). .

In the traveling body drive device having such a structure, when the first traveling body is directly driven in the direction of arrow A in FIG. 2, the first belt and the two moving pulleys 210A, 2
10B and a second belt and two moving pulleys 210C,
By the operation of 210D, the second traveling body 8 is driven from both sides thereof at a speed half that of the first traveling body 8. As a result, the first and second traveling bodies 8 and 302 can be driven in the sub-scan at a speed ratio of 2: 1. FIG. 5A shows a state where the reading scanning is started, and FIG. 5B shows a state where the reading scanning is finished. The arrow A direction in FIG. 5 represents the same direction as the arrow A direction in FIGS. Here, four bearings 201 fitted to the first guide shaft 202
As A, 201B, 204A, and 204B, for example,
In addition to the sliding bearing in which a round bar and a round hole are combined, a combination of a rolling bearing and a pressure member may be used.

As described above, the first traveling body and the second traveling body, each of which holds the optical element, are directly driven by the linear motor installed on the first traveling body, and the speed ratio is 2: 1 in the sub-scanning direction. In an image reading apparatus that reads an image by moving to, a movable back yoke and a movable coil are installed on the upper surface of the first traveling body, that is, on the document side, and an air gap of a linear motor is formed above the movable back yoke and the movable coil.
Since the drive magnet and the fixed back yoke are installed in the image reading apparatus main body at a position facing the movable coil,
In the traveling body drive device in which the linear motor is installed on the first traveling body, the linear motor can be easily attached.

Next, a second embodiment will be described. Figure 6
Shows a configuration of a traveling body drive device in a second embodiment corresponding to claim 2. In each of the following embodiments, the same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted as appropriate. In the second embodiment, the fixed back yoke 310 for forming the magnetic circuit is omitted. That is, the drive magnet 207 is directly installed on the image reading apparatus main body 311. This is easily possible if the entire image reading device body 311 is made of the same material as the fixed back yoke 310. In this case, the magnetic circuit of the linear motor is formed by the magnet 207, the movable back yoke 205, and the image reading device main body 311. At this time, what is made of the same material as the fixed back yoke may be limited to only the portion in contact with the magnet 207. As described above, according to the second embodiment, the main body of the image reading device or the entire main body of the image reading device at the portion where the drive magnet is attached is made of the same material as the fixed back yoke, and the fixed back yoke is omitted. It is possible to reduce the number of constituent parts of the traveling body drive device according to the first aspect of the invention and easily assemble the linear motor.

Next, a third embodiment will be described. Figure 7
Represents a structure of a traveling body drive device in a third embodiment corresponding to claim 3. In the third embodiment, the movable back yoke 205 for forming a magnetic circuit is omitted, and the coil 206 is installed directly on the first traveling body 8. This is easily possible if the first traveling body is made of the same material as the movable back yoke. In this case, the magnetic circuit of the linear motor is formed by the magnet 207, the fixed back yoke 310, and the first traveling body 8. At this time, what is made of the same material as the movable back yoke may be limited to only the portion in contact with the coil 206. Thus, according to the third embodiment, the first traveling body or the entire first traveling body of the portion to which the coil is attached is made of the same material as the movable back yoke, and the movable back yoke is omitted. It is possible to easily assemble the linear motor by reducing the number of components of the traveling body drive device of the first and second inventions.

Next, a fourth embodiment will be described. Figure 8
Shows a configuration of a traveling body drive device in a fourth embodiment corresponding to claim 4. In the fourth embodiment, the fixed back yoke 310 for forming a magnetic circuit is fixed to the image reading apparatus main body 311 via a ferromagnetic material 801 such as permalloy. Normally, the magnetic circuit of the linear motor is designed so that a closed loop is drawn by the magnet 207, the fixed back yoke 310, and the movable back yoke 205, but magnetism may leak to the image reading apparatus main body 311 depending on various dimensions and the characteristics of the magnet. . According to the present embodiment, the lines of magnetic force pass through the ferromagnetic body without leaking to the image reading apparatus main body 311 by interposing the ferromagnetic body. Therefore, since the magnetic force does not reach the image reading apparatus main body 311, there is no adverse effect such as sucking the surrounding magnetic material such as iron.

FIG. 9 shows a modification of the fourth embodiment, which corresponds to the fourth aspect. In the modification of the fourth embodiment, a movable back yoke 205 for forming a magnetic circuit is formed.
Through a ferromagnetic material 1001 such as permalloy
The structure is fixed to the traveling body 8. According to this modification, the lines of magnetic force pass through the ferromagnetic body without leaking to the first traveling body 8 because the ferromagnetic body is interposed. For this reason, since the magnetic force does not act on the first traveling body 8, it is possible to prevent the traveling body from being adversely affected by the leakage magnetic flux and the like.

Next, a fifth embodiment will be described. Figure 1
Reference numeral 0 represents the structure of the traveling body drive device according to the fifth embodiment of the present invention. In the fifth embodiment, the ferromagnetic material 801 for preventing magnetic flux leakage and the image reading device main body 311 are arranged so that the air gap 902 is interposed therebetween.
The magnet 207, the fixed back yoke 310, and the leakage magnetic flux preventing ferromagnetic material 801 are fixed to the image reading apparatus main body 311 by an auxiliary plate 901. The auxiliary plate 901 is preferably a non-magnetic material so as not to adversely affect the magnetic circuit, and an aluminum plate is used, for example. According to this embodiment, the magnetic flux leaking from the surface of the ferromagnetic material passes through the air gap 902 before reaching the image reading device main body 311, and flows to the ferromagnetic material 801. Therefore, since the magnetic force does not reach the main body of the image reading apparatus, there is no adverse effect such as sucking the surrounding magnetic material such as iron.

FIG. 11 shows a modification of the fifth embodiment corresponding to the fifth aspect. In the modification of the fifth embodiment, the leakage magnetic flux preventing ferromagnetic body 1001 and the first traveling body 8 are arranged so as to interpose the air gap 1101.
The coil 206, the movable back yoke 205, and the ferromagnetic body 1001 for preventing the leakage magnetic flux are first provided on the auxiliary plate 1102.
It is fixed to the traveling body 8. The auxiliary plate 1102 is also preferably made of a non-magnetic material such as aluminum so as not to adversely affect the magnetic circuit. According to this modification, the magnetic flux leaking from the surface of the ferromagnetic body passes through the air gap 1101 before reaching the first traveling body 8 and flows to the ferromagnetic body 1001. Therefore, since the magnetic force does not reach the first traveling body 8,
It is possible to prevent the traveling body from being adversely affected by the leakage magnetic flux and the like.

Next, a sixth embodiment will be described. Figure 1
2 and FIG. 13 show the structure of a traveling body drive device in a sixth embodiment corresponding to the sixth aspect. Figure 1
2 shows the traveling body driving device as seen from the mover side of the ultrasonic motor, and FIG. 13 shows the relative relationship between the first traveling body, the ultrasonic motor attached to the first traveling body, and the image reading apparatus main body. In the sixth embodiment, the movable element 1201 of the ultrasonic motor is attached to the upper surface of the first traveling body 8 so that the contact point with the ultrasonic motor stator 1301 faces upward. ing. The ultrasonic motor stator 1301 is fixed to the image reading apparatus main body 311 at a position facing the ultrasonic motor mover 1201. With such a configuration, when the ultrasonic motor is driven,
The first traveling body 8 can be directly driven in the direction of arrow A in FIG.

According to the sixth embodiment, the first traveling body and the second traveling body which respectively hold the optical elements are directly driven by the ultrasonic motor installed in the first traveling body,
In an image reading device that reads an image by moving in the sub-scanning direction at a speed ratio of 2: 1, an ultrasonic motor mover is installed on the upper surface of the first traveling body, that is, on the original side, and the stator of the ultrasonic motor is installed above it. Since it is installed in the image reading device main body at a position facing the ultrasonic motor mover, the ultrasonic motor can be easily attached in the traveling body drive device in which the ultrasonic motor is installed in the first traveling body. .

[0023]

According to the first aspect of the present invention, the first traveling body and the second traveling body holding the optical element are directly driven by the linear motor installed on the first traveling body, and the speed ratio of 2 to 1 In an image reading device that reads an image by moving in the scanning direction, a movable back yoke and a movable coil are installed on the upper surface of the first traveling member on the original side, and a linear motor is driven so that an air gap is formed above the movable back yoke and the movable coil. Since the magnet and the fixed back yoke are installed in the main body of the image reading device at a position facing the movable coil, it is possible to easily attach the linear motor in the traveling body drive device in which the linear motor is installed in the first traveling body. it can. According to a second aspect of the present invention, in the traveling body drive apparatus according to the first aspect, the image reading apparatus main body of the portion to which the drive magnet is attached or the entire image reading apparatus main body is made of the same material as the fixed back yoke, and the fixed back yoke is omitted. Therefore, it is possible to reduce the number of components of the traveling body drive device and to easily assemble the linear motor. According to a third aspect of the invention, in the traveling body drive apparatus according to the first and second aspects, the entire first traveling body or only a portion to which the movable back yoke is attached is made of the same material as the movable back yoke, and the movable back yoke is omitted. Therefore, it is possible to reduce the number of components of the traveling body drive device and to easily assemble the linear motor. According to a fourth aspect of the present invention, in the traveling body drive device according to the first to third aspects, between the fixed back yoke and the image reading device body, or between the movable back yoke and the first traveling body. Since the ferromagnetic material is installed on at least one side, it is possible to prevent the magnetic force from reaching the main body of the image reading device or the first running body, and therefore, to absorb the magnetic material such as iron around it. It is possible to prevent adverse effects. According to a fifth aspect of the invention, in the traveling body drive device according to the fourth aspect, an air gap is provided between at least one of the ferromagnetic body and the image reading apparatus main body or the ferromagnetic first traveling body. Since it is provided, it is possible to prevent the magnetic force from exerting on the image reading apparatus main body or the first traveling body, and thus it is possible to prevent the traveling body from being adversely affected by the leakage magnetic flux and the like. In the invention of claim 6, the first traveling body and the second traveling body which hold the optical element are
In an image reading device that directly drives a linear motor installed on the first traveling body and moves in the sub-scanning direction at a speed ratio of 2: 1 to read an image, an ultrasonic motor movable element is provided on the upper surface of the first traveling body, that is, on the document side. Was installed and the ultrasonic motor stator was installed on the upper side of the main body of the image reading device.
In the traveling body drive device in which the ultrasonic motor is installed on the first traveling body, it is possible to easily attach the ultrasonic motor.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an optical system of an image reading apparatus in which a traveling body driving apparatus according to an embodiment of the present invention is used.

FIG. 2 is a configuration diagram of the traveling body drive device according to the first embodiment as seen from an air gap of a linear motor.

FIG. 3 is a configuration diagram showing a relative relationship between the first traveling body of the traveling body drive device, the attached linear motor, and the image reading apparatus main body.

FIG. 4 is a side view of a linear motor unit of the traveling body drive device.

FIG. 5 is an explanatory diagram showing a driven method of the second traveling body in the traveling body drive device.

FIG. 6 is a configuration diagram of a traveling body drive device according to a second embodiment of the present invention.

FIG. 7 is a configuration diagram of a traveling body drive device according to the third embodiment.

FIG. 8 is a configuration diagram of a traveling body drive device according to the fourth embodiment.

FIG. 9 is a configuration diagram of a modified example of the traveling body drive apparatus according to the fourth embodiment.

FIG. 10 is a configuration diagram of a traveling body drive device according to the fifth embodiment.

FIG. 11 is a configuration diagram of a modified example of the traveling body drive apparatus according to the fifth embodiment.

FIG. 12 is a configuration diagram of the traveling body drive apparatus according to the sixth embodiment as seen from the mover side of the ultrasonic motor.

FIG. 13 is a configuration diagram showing a relative relationship between a first traveling body, an ultrasonic motor attached to the first traveling body, and an image reading apparatus main body according to the sixth embodiment.

[Description of Reference Signs] 0 Image Original 1 Contact Glass 2 Halogen Lamp 3, 4, 5, First Mirror, Second Mirror, Third Mirror 6 Lens 7 CCD Sensor 8 First Traveling Body 201A, B, C, D Bearing Unit 202, 203 1st guide shaft, 2nd guide shaft 302 2nd running body 204A, B, C, D bearing 205 movable back yoke 206 coil 311 image reading device main body 310 fixed back yoke 207 magnet 208, 209 first belt, second 2 Belts 20, 20 'Belt ends 501A, 501B Shafts 201A, 201B Dynamic pulleys 801, 1001 Ferromagnetic materials 902, 1101 Air gap 1201 Ultrasonic motor mover 1301 Ultrasonic motor stator

Claims (6)

[Claims] 1. A first traveling body and a second traveling body holding optical elements are directly driven by a linear motor installed on the first traveling body, and moved in a sub scanning direction at a speed ratio of 2: 1 to form an image. In the image reading apparatus for reading the above, a movable back yoke and a movable coil are installed on the upper surface of the first traveling body on the original side, and a drive magnet and a fixed back yoke are provided on the upper side so that an air gap of a linear motor is formed. A traveling body drive device, which is installed in an image reading device body at a position facing a movable coil. 2. The running body according to claim 1, wherein the main body of the image reading device or the entire main body of the image reading device at the portion where the drive magnet is attached is made of the same material as the fixed back yoke, and the fixed back yoke is omitted. Drive. 3. The traveling body drive apparatus according to claim 1, wherein the entire first traveling body or only a portion to which the movable back yoke is attached is made of the same material as the movable back yoke, and the movable back yoke is omitted. . 4. A ferromagnetic material is installed between at least one of the fixed back yoke and the main body of the image reading apparatus, or between the movable back yoke and the first traveling body. The traveling body drive device described. 5. The running body according to claim 4, wherein an air gap is provided between at least one of the ferromagnetic body and the main body of the image reading device or between the ferromagnetic body and the first running body. Drive. 6. The first traveling body and the second traveling body holding the optical element are directly driven by a linear motor installed on the first traveling body, and moved in the sub-scanning direction at a speed ratio of 2: 1 to form an image. In the image reading apparatus for reading, the moving body drive characterized in that the ultrasonic motor mover is installed on the upper surface of the first running body, that is, the document side, and the ultrasonic motor stator is installed on the upper side of the first running body and the image reading apparatus body. apparatus.