JP3595750B2 - Motor device - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a motor device for reducing vibration of a motor, and more particularly to a motor device suitable for an image reading device and the like.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in an image reading apparatus used for a copying machine or the like, a stepping motor is used because highly accurate positioning of a movable member is required. In order to drive the movable member of the image reading apparatus with low vibration and high speed by the stepping motor, it is essential to have the motor through-up and through-down.
[0003]
In addition, since reading at a constant speed without vibration is necessary to read color information, it is common in the design of the apparatus to provide a run-up distance required until vibration generated after through-up does not vibrate. ing.
[0004]
In addition, regarding the vibration at the constant speed portion of the motor rotation, the motor becomes a vibration source due to the torque ripple according to the step angle, and jaggies (hereinafter referred to as jaggies) occur in the thin lines of the image. To solve this problem, the rotation between the step angles is made smooth by using a magnet damper that gives inertia to the motor shaft at a constant speed without giving inertia to the motor shaft at the time of the through-up for the reason described later. Yes, it is possible to reduce vibration.
[0005]
Further, it is also possible to reduce the torque ripple by subdividing the step angle of the motor to reduce the vibration.
[0006]
However, since the number of readings per unit time of the image reading apparatus is increasing year by year, it is becoming impossible to take a sufficient approach distance. Also, if the inertia that works during acceleration is attached to the motor shaft, the through-up time increases, so that the speed cannot be increased and a large inertia cannot be provided. For this reason, the vibration component at the leading end of the read image is increased, and jaggies and the like are generated, which is a factor that greatly reduces the image quality.
[0007]
[Problems to be solved by the invention]
For the reasons described above, it is a factor that greatly reduces image quality due to jaggies and the like, and a factor that hinders downsizing of the apparatus due to an increase in the approach distance due to an increase in reading speed.
[0008]
Therefore, an object of the present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a motor device in which vibration generated at the time of acceleration and at the time of constant speed is reduced.
Still another object of the present invention is to use a magnet damper as the first damper means and a rubber damper as the second damper means. Still another object of the present invention is to shorten the reading time of an image reading apparatus by using a magnet damper and a rubber damper to speed up the apparatus.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a motor having a drive shaft, an image reading means having a moving unit to which drive is transmitted from the drive shaft of the motor and moving, and an image reading means for reading an image; A magnet damper attached to the shaft and increasing the inertial force applied to the drive shaft when the motor drive shaft is rotating at a predetermined speed at a constant speed than when the motor drive shaft is accelerated to a predetermined speed; A rubber damper having rubber and absorbing vibration generated when the drive shaft is accelerated to a predetermined speed from the start of driving, wherein the rubber damper is used during acceleration from the start of driving of the drive shaft to the predetermined speed. , Vibration is absorbed, and when a predetermined speed is reached, the vibration is reduced by a magnet damper.
[0011]
【Example】
Hereinafter, the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram of an image processing unit circuit of a digital full-color copying machine according to the present invention. In the figure, reference numeral 100 denotes a main board of the image processing circuit, which includes the following components.
[0012]
Reference numeral 101 denotes a three-line CCD that separates reflected light from a document into electric signals by color separation. An A / D converter 102 converts an analog RGB signal from the CCD 101 into a digital signal.
[0013]
The shading correction unit 103 corrects the sensitivity of each pixel of the CCD 101 and corrects the inclination of the light amount of the light source. In the figure, R (red), G (green), and B (blue) signals are 8-bit digital image signals output from the A / D converter 102.
[0014]
The CCD 101 used in the present embodiment has three CCD licensors for R (red), G (green), and B (blue) at a certain distance. For this reason, this digital image signal is a signal having a temporal shift caused by a spatial shift. This time shift is corrected in the line connection unit 104 in FIG.
[0015]
The input masking unit 105 performs an operation for correcting the RGB spectral characteristics of the CCD 101 into a standard RGB space.
[0016]
The LOG conversion unit 106 is a look-up table formed of a RAM, and the luminance signals of R (red), G (green), and B (blue) are respectively converted into C (cyan), M (magenta), and Y (yellow). It is converted to a density signal.
[0017]
The masking UCR unit 107 performs an operation of removing dust from the input C (cyan), M (magenta), and Y (yellow) density signals to a toner color used for print recording, and outputs a Bk (black) signal. appear.
[0018]
The F value correction unit 109 is a correction table for correcting the density value (F value) for each color according to the specification of the density to be printed. Reference numeral 108 denotes a tristate buffer, which is controlled by the ADD-IN signal. Reference numeral 110 denotes an image processing substrate. The image processing substrate 110 includes a 3-state buffer 111 and an image processing unit 112. The image processing unit 112 is a unit that performs processing such as extracting an outline of an image. The inverted signal of the ADD-IN signal is input to the tristate buffer 111. For this reason, the tristate buffer 111 and the tristate buffer 108 have an opposite relationship such that if one has a high impedance, the other has a low impedance. Therefore, when the ADD-IN signal is "1", the tristate buffer 108 becomes high impedance, and the image signal flows in the order of the masking UCR unit 107, the image processing unit 112, the tristate buffer 111, and the F value correction unit 109. . Conversely, when the ADD-IN signal is "0", the tristate buffer 111 becomes high impedance, and the image signal flows in the order of the masking UCR unit 107, the tristate buffer 108, and the F value correction unit 109.
[0019]
FIG. 2 is a block diagram illustrating a schematic configuration of the color image reading apparatus according to the present embodiment.
[0020]
The apparatus includes a document glass 202 on which a document 201 is loaded, and a document table cover 203 for pressing the loaded document 201, and a document illumination lamp 209 and a first mirror table below these. 204, a second mirror base 205, an imaging lens 206, and a color CCD (fixed image element) licensor (not shown) having three color separation filters (not shown) of R (red), G (green), and B (blue). An optical system including a licensor 207 and an image processing circuit 208 is provided.
[0021]
A mirror 210 is fixed to the first mirror base 204, and mirrors 211 and 212 are fixed to the second mirror base 205, respectively. The CPU 213 is connected to the image processing circuit 208, and the operation thereof is controlled by the CPU 213. The operation of the document illumination lamp 209 is controlled by a drive circuit (not shown), and the operation of the first and second mirror tables 204 and 205 is controlled by the CPU 213 via a drive mechanism (not shown).
[0022]
The first mirror table 204 and the document illumination lamp 209 scan the document 201 placed on the document table glass 202 at twice the speed of the second mirror table 205.
[0023]
The document 201 placed on the platen glass 202 is illuminated by a document illumination lamp 209. The reflected light is guided by mirrors 210, 211, and 212, and forms an image on the licensor 207 via the imaging lens 206. The reflected light is separated into R, G, and B components as color image information by a color separation filter of the licensor 207, and then sent to the image processing circuit 208. By repeating electrical scanning (main scanning) by the licensor 207 and mechanical scanning (sub-scanning) by the original illumination lamp 209 and the mirrors 210 to 212, image information of the entire original is read.
[0024]
The image processing circuit 208 performs predetermined image processing on the input image information, and outputs the image information to an externally connected printer or the like as an image signal.
[0025]
FIG. 9 is a perspective view showing a moving mechanism for moving the image reading device. This configuration is a known configuration used in a general flat bed type image reading apparatus. In order to scan the original, the original illumination lamp 209 and the first mirror 210 of the illumination source are moved at a predetermined speed, for example, as indicated by arrows, and the second and third mirrors 211 and 212 are moved. Moves at half its speed.
[0026]
For this purpose, the rotation is transmitted from the motor 40 to the rotation shaft 44 via the belt 42, and further, the rotation of the rotation shaft 44 is transmitted to the belt 48 wrapped around the pulley 46, and the first mirror base 204 attached to the belt 48 , A document illumination lamp 209 and a first mirror 210 as an illumination source are mounted, and a second mirror stand 205 is mounted with a second mirror and a third mirror 211 and 212.
[0027]
Now, assuming that the original image is read when the first mirror table 204 and the second mirror table 205 move in the directions indicated by the arrows, in order to obtain a high-quality image with less jaggies, the first mirror table and the second mirror table are required. It is desirable that the vibration of the as little as possible.
[0028]
Therefore, the present invention selects a magnet damper from a plurality of types of dampers that can be attached to a motor shaft, and studies this magnet damper. In the configuration of the moving mechanism to which the magnet damper is attached, vibration occurs when the first mirror 210 is slewed up to a predetermined speed.
[0029]
FIG. 3 shows a simplified view of a moving mechanism with only a magnet attached. Here, for simplicity of explanation, only the first mirror base is driven, but the same can be said for the case where the second mirror is attached.
[0030]
In the figure, reference numeral 301 denotes a stepping motor (corresponding to a motor indicated by reference numeral 40 in FIG. 9) as an example of a driving source of the moving mechanism. Reference numerals 302 and 303 (reference numerals 46 and 46 in FIG. 9) denote wire pulleys, and reference numeral 307 denotes a minimum force F required to move the first mirror base 306. 305 is an external force Fa. Reference numeral 306 (reference numeral 204 in FIG. 9) denotes a first mirror base, and its weight is W. Also. 309 is a rail for the first mirror base to move in parallel. The first mirror base moves with a friction coefficient μ between the first mirror base and the rail.
Here, F = Fa + μW. (However, μ: coefficient of friction)
[0031]
In the figure, reference numeral 310 denotes a magnet damper, which has a configuration having inertia connected to the motor shaft by a magnet, in which the motor shaft does not react to acceleration operations such as acceleration and deceleration, and the motor shaft has a constant speed. In the case of, it is configured to have inertia.
[0032]
FIG. 11 shows an external view of the magnet damper. Reference numeral 1101 denotes an inertia body of the magnet. 1103 is a hub made of iron. 1102 is a luron made of a material having a low coefficient of friction, such as Teflon. At the time of motor acceleration, the inertia of the magnet damper applied to the motor shaft is weak because the hub of 1103 and the inertia body 1101 of the magnet are slidably moved because the luron 1102 is attached to the motor shaft. On the other hand, when the motor shaft rotates at a constant speed, the inertia of the magnet damper added to the motor shaft is added because the hub of 1103 and the inertial body 1101 of the magnet are attached to rotate together.
[0033]
FIG. 5 shows a simplified equivalent diagram of a motor using only a magnet damper. In the drawing, reference numerals 501 and 502 represent springs, and reference numeral 503 (corresponding to the reference numeral 301 in FIG. 3) denotes a motor, which together with the springs 501 and 502 serves as a vibration source. Reference numeral 504 indicates that the inertial body 505 (corresponding to the reference numeral 1101 in FIG. 11) formed by a magnet is connected to the motor 503 as a vibration source. The inertial body 505 does not react during acceleration because it is connected by a magnet, and when the motor is at a constant speed, the inertial body 505 is added to the motor 503 as a vibration source.
[0034]
FIG. 4 is a diagram showing the relationship between the state of vibration of the first mirror base 306 and the motor speed when the motor is through-upped in this configuration. In the figure, reference numeral 401 denotes a waveform showing how the vibration generated at the time of motor through-up is attenuated. The axis in the Y direction indicates acceleration G, and the X direction indicates time t. Reference numeral 402 denotes a motor through-up waveform, in which the Y direction represents speed and the X direction represents time t. In the waveform of 402, reference numeral 404 denotes an acceleration region, reference numeral 405 denotes an approach region for removing a vibration generated at the time of through-up, and reference numeral 406 denotes an image reading region for reading an image without vibration during the through-up. Here, in the moving mechanism equipped with only the magnet damper, the time t1 is required from the start of the motor until the vibration at the time of the through-up is attenuated and the image can be read.
Here, in the present invention, it has been devised to attach another damper to the motor shaft to which the magnet damper is attached, and a rubber damper is selected from a plurality of types of dampers that can be attached to the motor shaft as this still another damper. Things.
[0035]
FIG. 6 shows a simplified view of a moving mechanism to which two dampers of a magnet damper and a rubber damper of the present invention are attached. Here, for simplicity of explanation, only the first mirror base is driven, but the same can be said for the case where the second mirror is attached.
[0036]
In the figure, reference numeral 601 denotes a stepping motor as an example of a driving source of the moving mechanism. 602 and 603 are wire pulleys, and 607 is a minimum force F required to move the first mirror base 606. 605 is an external force Fa. Reference numeral 606 denotes a first mirror stand whose weight is W. Reference numeral 609 denotes a rail for the first mirror base to move in parallel. That is, the components denoted by reference numerals 601 to 609 in FIG. 6 correspond to the components denoted by reference numerals 301 to 309 in FIG. 3, respectively. Then, the first mirror base moves with a friction coefficient μ between itself and the rail.
Here, F = Fa + μW. (However, μ: coefficient of friction)
[0037]
In the figure, reference numeral 610 denotes a magnet damper, which has a configuration in which the motor shaft is connected to the motor shaft by a magnet and has inertia. The motor shaft does not respond to acceleration operations such as acceleration and deceleration, and the motor shaft has a constant speed. In the case of, it is configured to have inertia. Reference numeral 611 denotes a rubber damper, which is mounted on the motor shaft and is mounted to reduce vibration generated at the time of through-up.
[0038]
Here, the point that a rubber damper is selected as another damper will be described in detail. FIG. 7 shows a simplified equivalent diagram of a motor using only a rubber damper. In the drawing, 701 and 702 represent springs, 703 is a motor, and together with the springs 701 and 702, become a vibration source. Reference numeral 704 denotes a spring, reference numeral 705 denotes a dash pot, reference numeral 706 denotes inertia (inertia), which are equivalent components of the rubber damper 707.
[0039]
FIG. 10 is an external view of the rubber damper. Reference numeral 1001 denotes an inertia, which is made of iron or the like. A hub 1003 is connected to a motor shaft. A rubber material 1002 changes the characteristics of the spring 704 and the dashpot 705 depending on the material. Therefore, it is possible to load the spring-mass system by the rubber damper in accordance with the natural frequency of the load generated at the time of the through-up and to suppress the vibration by utilizing resonance (hereinafter, dynamic vibration absorption).
[0040]
The center frequency for absorbing the dynamic vibration is shown below.
f = (1 / 2π) × {980 × (K / J)} − ²
Here, f: dynamic vibration absorption frequency, K: spring constant (g · cm / rad), and J: moment of inertia (g · cm).
Therefore, the vibration at the time of through-up is reduced by changing the rubber material of 1002 relating to the spring constant and the inertia of 1001 in accordance with the natural vibration frequency of the load at the time of through-up of the image reading system.
[0041]
FIG. 8 is a diagram showing the relationship between the state of vibration of the first mirror base 606 and the speed of the motor when the motor is slewed up with the configuration of the moving mechanism using the rubber damper. In the figure, reference numeral 801 is a diagram showing how the vibration generated at the time of motor through-up is attenuated. The axis in the Y direction indicates acceleration G, and the axis in the X direction indicates time t.
[0042]
Reference numeral 802 denotes a through-up waveform of the motor, in which the Y direction represents speed and the X direction represents time t. In the waveform 802, reference numeral 805 denotes an acceleration region, reference numeral 806 denotes a run-in region for removing vibration generated at the time of through-up, and reference numeral 807 denotes an image reading region for reading an image without vibration at the time of through-up.
[0043]
Here, the time t2 (803) from the start of the motor until the vibration at the time of the through-up is attenuated and the image can be read is reduced by Δt (804) from the time t1 of the moving mechanism using only the magnet damper described above. It is possible to do.
[0044]
As described above, the natural vibration of the load system, which has conventionally occurred at the time of motor through-up, can be reliably and efficiently reduced by adding the rubber damper to the image reading drive system. As a result, the run-up time for absorbing the vibration generated at the time of the through-up can be reduced, so that the image reading time can be shortened, which contributes to an increase in the speed of the device. In addition, the running distance is also reduced, which contributes to downsizing of the device.
[0045]
For this reason, the present invention focuses on the fact that if two damper means are attached to the motor drive shaft as shown in FIG. The use of a magnet damper as the means and the use of a rubber damper as the second damper means reduce vibrations generated during acceleration and at a constant speed, which is used to drive the moving mechanism of the image reading device. By using the motor, the reading time of the image reading device can be shortened and the speed of the device can be increased. Here, FIG. 12 shows a simplified equivalent view of a motor using two dampers, a magnet damper and a rubber damper.
[0046]
In the drawing, 701 and 702 represent springs, 703 is a motor, and together with the springs 701 and 702, become a vibration source. Reference numeral 704 denotes a spring, reference numeral 705 denotes a dash pot, reference numeral 706 denotes inertia (inertia), which are equivalent components of the rubber damper 707. Reference numeral 504 indicates that the inertial body 505 made of a magnet and the motor 503 as a vibration source are connected. The inertial body 505 does not react during acceleration because it is connected by a magnet, and when the motor is at a constant speed, the inertial body 505 is added to the motor 503 as a vibration source.
[0047]
【The invention's effect】
As described above, according to the present invention, the natural vibration of the load system can be reliably and efficiently reduced by the rubber damper at the time of motor through-up, and the rotation between the step angles by the magnet damper at the constant speed of the motor. Can be smoothed, and vibration can be reduced.
[Brief description of the drawings]
FIG. 1 is an image processing block circuit diagram of a digital full-color copying machine according to the present invention.
FIG. 2 is a configuration diagram of an image reading apparatus including the image processing block circuit diagram of FIG. 1;
FIG. 3 is a simplified diagram of a moving mechanism including only a magnet damper.
FIG. 4 is a diagram illustrating a relationship between a state of vibration of a first mirror of the image reading apparatus and a motor speed illustrated in FIG. 3;
FIG. 5 is a simplified equivalent view of a motor using only the magnet damper shown in FIG. 3;
FIG. 6 is a simplified diagram of a moving mechanism using two damper means of a magnet damper and a rubber damper according to one embodiment of the present invention.
FIG. 7 is a simplified equivalent view of a motor using only a rubber damper.
FIG. 8 is a diagram illustrating a relationship between a state of vibration of a first mirror of the image reading apparatus and a motor speed illustrated in FIG. 7;
FIG. 9 is a configuration diagram illustrating a moving mechanism for moving the image reading apparatus illustrated in FIG. 2;
FIG. 10 is a view of the rubber damper shown in FIG. 7;
FIG. 11 is a diagram of the magnet damper shown in FIG. 3;
FIG. 12 is a simplified equivalent view of a motor using the magnet damper and the rubber damper shown in FIG.
[Explanation of symbols]
610 Magnet damper 611 Rubber damper 801 Attenuation of vibration generated at the time of motor through-up 802 Motor through-up waveform 1001 Inertia 1002 Rubber material 1003 Hub

Claims (2)

A motor having a drive shaft, an image reading means for reading an image, having a moving portion to which drive is transmitted from the drive shaft of the motor, and an image reading means for reading an image; and It has a magnet damper that increases the inertial force applied to the drive shaft when the drive shaft of the motor is rotating at a predetermined speed at a constant speed than when the motor is accelerated, and a rubber. And a rubber damper that absorbs vibration generated when accelerating up to
An image reading apparatus wherein vibration is absorbed by a rubber damper during acceleration from a start of driving of a drive shaft to a predetermined speed, and the vibration is reduced by a magnet damper when the speed reaches a predetermined speed. 2. The image reading device according to claim 1, wherein inertia of the rubber damper is smaller than inertia of the magnet damper.

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