JPH11136975A - Equipment having vibration type drive apparatus, image forming apparatus and vibration type actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lengthen the operation life of a vibration type actuator by providing status detection means which generate a signal when a predetermined status has occurred and by locking once the drive parameters of a control circuit immediately after detecting the signal of the status detection means by drive control means. SOLUTION: When this operation is started, speed control is executed by a drive frequency (#01), a status detection sensor is checked to find whether it is normal during that time period (#02), if it is normal, then the speed control is executed and the frequency is controlled to obtain a target speed. Also, if the status detection sensor detects an abnormal state, the speed control operation is prohibited and the frequency is detected (#03). Then, a voltage from the power supply circuit is gradually lowered (#04), whether the power supply voltage is 0 or not is checked (#05), and if the power supply voltage becomes zero, then this operation is completed. That is, if the status sensor detect an abnormal state, the frequency is immediately fixed, the voltage is gradually lowered, and the voltage is finally reduced to zero and thus a smooth operation can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus including at least one of a vibration type driving device, a printing device, an image capturing device, and an image processing device.

[0002]

2. Description of the Related Art In general, a vibration type actuator has a piezoelectric element disposed at a position spatially having a phase difference of 90 ° with respect to an elastic body such as a metal, and these piezoelectric elements have a phase difference of 90 ° with each other. By applying a two-phase alternating signal having the following, a traveling wave is generated on the elastic body, and the elastic body and a contact body that comes into pressure contact with the elastic body via a pressurizing unit by frictional force. It is made to move relatively, and as the elastic body, there is a shape such as a ring shape, a rod shape,
When the vibrator is made of an elastic body and a piezoelectric element, and the vibrator is fixed, the contact body functions as a moving body.

[0003] A friction material for obtaining an appropriate frictional force is adhered, applied or formed on a contact portion between the vibrating body and the contact body.

[0004] The characteristics of such a vibration type actuator are that, compared to an actuator using electromagnetic force, the driving torque at low speed is large, the response is good, and human beings use vibrations beyond the audible range. The point that it is quiet because there is no driving noise is raised.

For this reason, a vibration type actuator is used as a drive source of a photosensitive drum as an image carrier of an image forming apparatus such as an electrophotographic copying machine, and a transfer material for transferring a transfer material such as transfer paper to a transfer position with the photosensitive drum. It has been proposed to use it as a drive source for a transport means.

In general, a vibration type actuator utilizes a resonance phenomenon, and therefore, speed control is performed by frequency or speed control by voltage.

[0007]

Incidentally, in the current image forming apparatus, an actuator utilizing electromagnetic force is generally used, and since such an actuator does not use frictional force as a driving principle, it is worn out due to sudden stop. Occurs, and the life is hardly affected.

Therefore, even when the state detecting circuit of the image forming apparatus detects a state other than a steady state (for example, when a door or the like is opened due to a paper jam) and stops the actuator, the actuator can be stopped without any special measures. did it.

However, in such an image forming apparatus, when a vibration type actuator is used as a drive source, for example, when a stop command is issued in response to the detection of the opening of the door, the power supply for power supply is cut off simultaneously with the detection of the opening of the door. Therefore, power is not supplied to the drive circuit of the vibration type actuator, and the vibration type actuator is suddenly stopped from the steady driving speed.

On the other hand, a vibration-type actuator transmits a driving force between a moving body and a vibration body via a frictional material. Therefore, unlike a conventional actuator using an electromagnetic force, the frictional material is rapidly stopped. May be stressed to shorten the life of the actuator. In other words, there is a problem that the sudden stop greatly affects the life.

Further, the vibration type actuator generally performs drive control with a frequency or a voltage. For example, in the case of the frequency control, when the state changes due to a paper jam, a voltage drop, and the like, when the speed of the vibration type actuator is reduced, The control circuit works to lower the frequency and increase the speed. However, when the limit point is reached, the speed drops rapidly due to hysteresis, causing a sudden stop. At this time, the friction material of the vibration type actuator may be damaged.

In the case of voltage control, the control circuit works to increase the voltage to increase the speed. In this case, the voltage becomes excessively large, the vibration amplitude becomes too large, and the friction member may be damaged.

It is an object of a first invention according to the present invention to extend the life of a vibration type actuator.

An object of a second invention according to the present application is to prevent a sudden stop when the state of an apparatus using a vibration-type actuator becomes an unsteady state and prolong the life of the vibration-type actuator.

The third and fourth objects of the present invention are to prevent the vibration amplitude from becoming too large when the state of the device using the vibration type actuator is not steady, and to reduce the life of the vibration type actuator. Is to make it longer.

A fifth object of the present invention is to prevent a sudden stop and an excessive increase in vibration amplitude when the state of a device using a vibration type actuator becomes an unsteady state. Is to make it longer.

According to the sixth, seventh, eighth, ninth,
An object of a tenth aspect of the present invention is to prevent a sudden stop and an excessive increase in vibration amplitude when the state of a device using a vibration type actuator is not stationary and to make the device safe.

An eleventh and twelfth aspect of the present invention is to prevent sudden stop and excessive increase in vibration amplitude when the state of an image forming apparatus using a vibration type actuator is not steady. And to keep the device safe.

It is an object of the thirteenth to nineteenth aspects of the present invention to extend the life of a vibration type actuator.

[0020]

In order to achieve the above-mentioned object, a vibration-type driving apparatus for realizing the object of the first invention according to the present invention is provided with a vibration-type actuator and a power generation circuit which is supplied with power. A drive control means for controlling a drive parameter of the vibration type actuator to be driven by a control circuit; and a state detection means for detecting a state of the apparatus and generating a signal when a predetermined state is reached, the drive control The means temporarily locks the drive parameters of the control circuit as soon as the signal of the state detecting means is detected.

According to a second aspect of the present invention, there is provided a vibration-type driving device, wherein the driving control means includes a driving parameter of a vibration-type actuator controlled by the control circuit being a frequency of an alternating signal; The frequency is fixed as soon as the state signal is detected.

According to a third aspect of the present invention, there is provided a vibration-type driving device, wherein a driving parameter of a vibration-type actuator controlled by the control circuit is a voltage of an alternating signal, and a signal of the state detecting means is controlled. Immediately upon detection, the voltage command is fixed.

According to a fourth aspect of the present invention, there is provided a vibration-type driving device, wherein the power generation circuit includes an alternating signal generating means for outputting an alternating signal by switching an inductance element, and switching to a switching element. A pulse generation circuit for giving a pulse, a power supply for supplying power to the inductance element, and a control parameter of the vibration type actuator controlled by the control circuit is a pulse width of the switching pulse, Immediately upon detection of the signal, the pulse width is fixed.

According to a fifth aspect of the present invention, there is provided a vibration-type driving device, wherein the power generation circuit of the vibration-type actuator outputs an alternating signal by switching an inductance element, and a switch. A pulse generating circuit for supplying a switching pulse to the switching element, and a power supply for supplying power to the inductance element, wherein the parameters of the vibration-type actuator controlled by the control circuit are the frequency and pulse width of the switching pulse. The frequency and the pulse width are fixed as soon as the state signal of the state detecting means is detected.

In the vibration type driving apparatus according to a sixth aspect of the present invention, after the driving parameters by the driving control means are once locked, the voltage from the power supply is gradually lowered, and finally the voltage is reduced to zero. Is what you do.

In a vibration type driving apparatus according to a seventh aspect of the present invention, the drive control means reduces the voltage stepwise by gradually reducing the pulse width.

In a vibration type driving apparatus according to an eighth aspect of the present invention, the state detected by the state detecting means is a drop in power supply voltage.

In a vibration type driving apparatus according to a ninth aspect of the present invention, the state detected by the state detecting means is a decrease in the output of the vibration type actuator.

A vibration type driving apparatus according to a tenth aspect of the present invention is provided in a housing having a door together with a high voltage section and a driving section, and the state detecting means detects a state in which the door is open. It is assumed that.

An image forming apparatus according to an eleventh aspect of the present invention is characterized in that one or a plurality of the above-mentioned vibration type driving devices are used in a driving system.

In the image forming apparatus according to a twelfth aspect of the present invention, the state detected by the state detecting means is an abnormal state of sheet feeding in the printing unit.

According to the thirteenth aspect of the present invention, there is provided an apparatus having a vibration-type actuator, comprising: an electric actuator provided on an elastic body;
In a device including a vibration-type actuator that obtains a driving force by applying a frequency signal to a mechanical energy conversion element, when driving of the vibration-type actuator is stopped in an emergency, the driving state of the vibration-type actuator is gradually stopped. Control means for shifting to a state is provided.

An apparatus having a vibration-type actuator according to a fourteenth aspect of the present invention is provided with state detecting means for detecting an operating state, an operating state, or a driving environment state of the apparatus. An apparatus provided with a vibration type actuator, wherein the emergency drive stop operation is performed when a state becomes a predetermined state.

According to a fifteenth aspect of the present invention, there is provided an apparatus having a vibration-type actuator, wherein the control means gradually reduces a frequency signal applied to the electro-mechanical energy conversion element, and To a stop state. In a device having a vibration-type actuator according to a sixteenth aspect of the present invention, the control means gradually reduces a voltage level of a frequency signal applied to the electro-mechanical energy conversion element.

According to a seventeenth aspect of the present invention, there is provided an apparatus having a vibration-type actuator, wherein the switching means for turning on and off in response to a pulse signal causes the electro-mechanical energy conversion element to turn on and off the pulse signal. A drive circuit for applying a frequency signal having a frequency corresponding to the synchronization is provided, and the control means performs the emergency drive stop operation by gradually narrowing the width of the pulse signal.

According to an eighteenth aspect of the present invention, there is provided the device having the vibration-type actuator, wherein the control means gradually changes a frequency signal applied to the electro-mechanical energy conversion element to thereby control the vibration. The drive state of the mold actuator is gradually shifted to a stop state.

A device having a vibration-type actuator according to a nineteenth aspect of the present invention shifts to a stop state by gradually changing the frequency of the frequency signal to a high frequency.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 is a flow chart showing the operation of the first embodiment of the present invention, FIG. 2 is a sectional view of the vibration type actuator of this embodiment, and FIG. 3 is the vibration type actuator of FIG. FIG. 4 shows a vibration type actuator,
FIG. 1 is a schematic sectional view of an image forming apparatus equipped with a vibration type driving device including the driving circuit and a driven body.

In FIG. 2, the vibration type actuator is
A piezoelectric element 4 as an electro-mechanical energy conversion element is bonded to the ring-shaped elastic body 3 at a position spatially having a phase difference of 90 ° with respect to each other. (A phase drive unit and a B phase drive unit) are formed on the surface of the elastic body 3 by applying two-phase alternating signals having a phase difference of 90 ° to each other. A traveling wave is being generated.

A rotor 1 as a moving body is pressed against the driving portion of the elastic body 3 by the spring force of a spring member 2 also serving as a transmitting member, so that the elastic body 3 is moved by the traveling wave.
, The rotor 1 is driven by friction. A friction member 28 having a predetermined friction coefficient different from that of the base material is provided at a contact portion between the vibrator and the rotor.

Reference numeral 6 denotes an output shaft, which is fixed to a spring member 2 integral with the rotor 1 so that the rotational force of the rotor 1 can be taken out. A is a base member that also serves as one of the motor cases. The ring-shaped elastic body 3 is fixed by screws, and a bearing that rotatably supports the output shaft 6 is mounted. B is a case member that constitutes the other of the motor case, and is attached to the base member A with screws.

FIG. 3 shows a driving circuit for driving the vibration type actuator. Since a voltage of several hundred volts is required for driving the vibration type actuator, an A-phase driving transformer 23 and a B-phase driving DC power supply circuit 5 is connected to the center tap on each primary side of transformer 24 for
MOSFET1 is connected to both ends on the primary side of the transformers 23 and 24
9, 20, 21 and 22 are connected, and a booster circuit for obtaining a high voltage by switching is used. Transformer 2 when driving
MOSFET 19 connected to both ends of the primary side of 3, 24
And 20 gates are connected by 180 ° phase shifter 9 and M
A 180 ° phase shifter 1 is connected to the gates of OSFETs 21 and 22.
With 0, a pulse having an arbitrary pulse width and frequency having a phase difference of 180 ° from each other is added.

The MOSFETs 19, 20, 21,
The phases of the pulses applied to the 22 gates are 0
And 180 °, and 90 ° and 270 °. In this way, pulses having a phase difference of 90 ° are output from the pulse shaping circuit 7 to the driving circuits.

Numeral 8 denotes a speed control circuit, which is a pulse shaping circuit for obtaining a speed command (target speed) value based on speed information from speed detecting means 26 for detecting the speed of the vibration type actuator (or driven body). 7 is controlled.

A state signal detected by a state sensor described later is also input to the speed control circuit 8. When this state signal is input, the operation shown in FIG. 1 is performed.

Further, a capacitor 27 is connected in parallel to the DC power supply circuit 5 to form a smoothing circuit.
Therefore, even if the power supply to the DC power supply circuit 5 is cut off (even if the power supply on the primary side of the transformer is cut off), the secondary voltage of the transformer is immediately reduced due to the characteristics of the smoothing circuit by the capacitor 27. However, as shown in FIG. 7, the vibration type actuator gradually decreases at a certain time constant, so that the speed of the vibration type actuator gradually decreases without immediately stopping.

FIG. 4 shows a color image forming apparatus using such a vibration type actuator as a drive source. The vibration type actuator is an image forming process unit 3 for each color.
The photosensitive drums 342 to 345 serving as image carriers of 17, 318, 319, and 320 are used for driving a driving roller 348 for driving a transfer material conveying belt 333.

The image forming process units are arranged in parallel along the transfer material transfer direction, that is, along the transfer material transfer direction of the transfer material transfer belt 333, and transfer the cyan, magenta, yellow, and black images, respectively. Do.

First, the configuration of the color reader will be described.

In FIG. 4, 101 is a CCD, 311 is a substrate on which the CCD 101 is mounted, 312 is a printer processing unit, 301 is a platen glass (platen), 302 is a document feeder (DF) (note that There is also a configuration in which a mirror pressure plate (not shown) is mounted instead of the paper device 302), 30
3 and 304 are light sources (halogen lamps or fluorescent lamps) for illuminating the original, 305 and 306 are reflectors for condensing light from the light sources 303 and 304 on the original, 307 to 309 are mirrors,
Reference numeral 310 denotes a lens for condensing reflected light or projection light from the original on the CCD 101, and 314 denotes a halogen lamp 303.3.
Reference numeral 315 denotes a carriage that houses the mirrors 308 and 309, and 313 denotes an interface (I / F) unit with another CPU or the like. Note that the carriage 314 has a speed V and the carriage 315 has a speed V / 2.
The entire surface of the document is scanned (sub-scanning) by mechanically moving in the direction perpendicular to the electrical scanning (main scanning) direction of
I do.

Next, the configuration of the printer unit will be described. 4, an M (magenta) image forming unit 317, a C (cyan) image forming unit 318, a Y (yellow) image forming unit 319, and K as image forming process units
(Black) Since the configuration of the image forming unit 320 is the same, the M image forming unit 317 will be described in detail, and the description of the other image forming units will be omitted.

In the M image forming unit 317, reference numeral 342 denotes a photosensitive drum on which a latent image is formed by the light from the LED array 210. A primary charger 321 charges the surface of the photosensitive drum 342 to a predetermined potential to prepare for forming a latent image. A developing device 322 develops the latent image on the photosensitive drum 342 to form a toner image. Note that the developing device 322 includes a sleeve 345 for applying a developing bias to perform development. A transfer charger 323 discharges the toner image on the photosensitive drum 342 from the back surface of the transfer material transport belt 333 to transfer the toner image on the photosensitive drum 342 to the transfer material transport belt 3.
The image is transferred to a recording paper on the recording medium 33. In the present embodiment, since the transfer efficiency is good, no cleaner section is provided. Needless to say, there is no problem even if the cleaner is mounted.

Next, a procedure for forming an image on a recording paper or the like will be described. The recording papers and the like stored in the cassettes 340 and 341 are picked up by pickup rollers 339 and 338.
The transfer material transport belt 33 is fed by the sheet feed rollers 336 and 337 for each sheet.
3 is supplied. The fed recording paper is supplied to the adsorption charger 3
Charged at 46. 348 is a transfer belt roller,
The transfer material transport belt 333 is driven, and the attraction charger 3
The recording paper and the like are charged in pairs with the recording material and the recording paper and the like are attracted to the transfer material transport belt 333.

A paper edge sensor 347 detects the edge of a recording paper or the like on the transfer material transport belt 333. The detection signal of the paper leading edge sensor is sent from the printer unit to the color reader unit, and is used as a sub-scan synchronization signal when a video signal is sent from the color reader unit to the printer unit.

Thereafter, the recording paper is transferred to the transfer material transport belt 3.
The toner image is formed on the surface of the image forming units 317 to 320 in the order of MCYK. The recording paper or the like that has passed through the K image forming unit 320 is separated from the transfer material transport belt 333 after the charge is removed by the charge removing charger 349 in order to facilitate separation from the transfer material transport belt 333.

Reference numeral 350 denotes a peeling charger, which prevents image disturbance due to peeling discharge when the recording paper or the like is separated from the transfer material transport belt 333. The separated recording paper and the like are charged by pre-fixing chargers 351 and 352 in order to compensate for the toner attraction force and prevent image disturbance, and then the fixing device 334.
After the toner image is thermally fixed, the sheet is discharged to a sheet discharge tray 335.

The photosensitive drums 342 to 345 of the image transfer apparatus according to the present embodiment are directly connected to a rotary shaft which is an output shaft of a rotary vibration type actuator as shown in FIG. By 4
The transfer portions (outer circumferences) of the two photosensitive drums are driven at the same rotational speed (peripheral speed). Also, a vibration type actuator is used for driving a driving roller 348 for driving the transfer material conveying belt 333, and is driven in synchronization with the above four transfer portions.

In such an image forming apparatus, the apparatus has the above-described driving portion, the transfer device, and the high-voltage portion for driving the vibration type actuator. Therefore, during normal use, a housing is provided to cover these parts so that a general user does not touch these parts during driving.

Such an image forming apparatus includes various state sensors (not shown) for detecting the state of the image forming apparatus, such as a paper jam sensor, a power supply voltage sensor, and a door open / close sensor. When such a sensor detects a non-steady state, it generates a state signal. This signal is input to the speed control circuit 8 in FIG.

In the present embodiment, the speed is controlled by the drive frequency while the pulse width is fixed. Since the vibration type actuator has frequency-speed characteristics as shown in FIG. 8, speed control can be performed by changing the drive frequency.

FIG. 9 shows the operation of the conventional example in the case where the speed of the vibration-type actuator is reduced due to a paper jam, a decrease in voltage, a decrease in the output of the vibration-type actuator, or the like.

In FIG. 9, when the speed of the vibration-type actuator decreases due to a change in the state (step: a),
The control circuit lowers the frequency in an attempt to maintain the speed (step: b). At this time, the maximum speed (Vmax) that the vibration type actuator can output is equal to the target speed (Vc).
If the control frequency is lower than the control frequency, the control frequency goes beyond the point fb to a frequency lower than the point fc, and as shown in the figure, the speed suddenly becomes 0 and stops suddenly (step: c).
Such an operation adversely affects the friction surface of the vibration-type actuator, and causes the life of the vibration-type actuator to be shortened. Also, immediately turning off the power supply shortens the life of the vibration type actuator for the same reason.

On the other hand, in this embodiment, when the state signal of the state sensor is input to the speed control circuit 8, the following operation is performed according to the flowchart of FIG.

The flowchart of FIG. 1 will be described.
When this operation (for example, copy operation) starts, speed control (target speed control) is executed based on the drive frequency (# 0).
1) In the meantime, check whether the state detection sensor is normal or not (#
02) If normal, speed control is executed to control the frequency so as to reach the target speed. When the state detection sensor detects an abnormality, the speed control operation is prohibited and the frequency is fixed (# 03).

Then, the voltage from the power supply circuit 5 is gradually reduced (# 04), and it is checked whether or not the power supply voltage (output voltage of the DC power supply circuit) is 0 (# 05). Then, this operation ends.

That is, when the state sensor detects an abnormal state, the frequency is fixed immediately, the voltage is gradually lowered, and finally the voltage is set to 0, so that the vibration-type actuator can be smoothly stopped. No longer stresses the friction material provided on the drive surface,
Life can be extended.

As described above, in a general stabilized power supply, even if the power supply on the primary side is cut off due to the characteristics of the smoothing circuit,
The secondary voltage does not immediately decrease, but gradually decreases at a certain time constant, as shown in FIG. 7, so that the speed of the vibration type actuator gradually decreases without immediately stopping.

Therefore, the operation of gradually lowering the voltage may be simply turning off the power supply on the primary side. In addition, in the circuit configuration shown in FIG. 3, if the capacity of electrolytic capacitor 27 is increased to some extent, even if the output of DC power supply circuit 5 is cut off, the voltage is not changed until electrolytic capacitor 27 is completely discharged. It gradually decreases as well. Therefore, it is only necessary to cut off the output of the DC power supply circuit 5. When the power is simply cut off, the step of determining whether the voltage of # 05 in the flowchart of FIG. 1 has become 0 can be omitted.

(Second Embodiment) FIG. 10 shows a second embodiment. The vibration type actuator and the driving circuit in the vibration type driving device according to the present embodiment are the same as those in the first embodiment, and the only difference is the control operation shown in FIG.

In the circuit of FIG. 3, when the pulse width of the pulse applied to the gates of MOSFETs 19 to 22 is changed, FIG.
The amount of current flowing into the transformer can be adjusted as
The voltage output to the secondary side of the transformer can be changed.

Since the driving speed of the vibration type actuator and the applied voltage have a relationship as shown in FIG. 6, the speed can be finally changed by the pulse width. Therefore, speed control can be performed also by the pulse width. In the second embodiment, speed control is performed by fixing the drive frequency and changing the pulse width.

Next, the operation of the second embodiment will be described with reference to FIG. FIG. 11 shows the pulse width on the horizontal axis and the speed on the vertical axis. When the speed characteristic of the vibration type actuator changes from PN1 to PN2 due to a paper jam or a decrease in voltage, the speed decreases (step: a). Then, in the conventional circuit, the control circuit increases the pulse width to maintain the speed (ste).
p: b). As a result, the pulse width increases to the limit pulse width PW2. In the circuit of FIG. 3, as the pulse width increases, the current flowing in the circuit increases, and as shown in FIG. 11, the loss of the circuit increases, and a heavy load is imposed on the drive circuit.

Further, in the case of a paper jam, the relationship between the vibration amplitude and the pulse width of the vibrating body of the vibration type actuator is almost the same as in the normal state, so that the vibration amplitude becomes too large and a large load is applied to the friction member and the like. Would.

As a result, the life of the vibration type actuator is shortened. On the other hand, in the present embodiment, FIG.
As shown in (1), when speed control is performed based on the pulse width (# 11), when the state detection sensor detects an abnormality such as a paper jam (# 12), the speed control is immediately inhibited and the pulse width is fixed (# 11). # 13). By doing so, it is possible to prevent the current and vibration amplitude from becoming excessive.

After fixing the pulse width, the voltage is gradually lowered (# 14), and finally set to 0 (# 15).

In this way, the vibration type actuator stops smoothly, and the life can be extended without applying stress to the friction member. In a general stabilized power supply, even if the power supply on the primary side is cut off due to the characteristics of the smoothing circuit, the secondary side voltage does not immediately decrease but gradually decreases with a certain time constant as shown in FIG. Therefore, the operation of gradually lowering the voltage may simply be to cut off the power supply on the primary side. FIG.
In such a circuit, if the capacity of the electrolytic capacitor 27 is increased to some extent, even if the output of the DC voltage power supply circuit 7 is cut off, the voltage is maintained until the electrolytic capacitor 27 is completely discharged.
It gradually decreases as well.

Therefore, in this case, it is sufficient to simply cut off the output of the DC voltage power supply circuit 5. When the power is simply cut off, the determination as to whether the voltage in FIG. 1 has become 0 can be omitted.

In FIG. 11, the operation is started after the pulse width is fixed and then the voltage is lowered. However, instead of lowering the voltage, when the signal of the state sensor is input, the pulse width is gradually lowered. May be performed, or both the pulse width and the voltage may be gradually reduced.

The circuit shown in FIG. 3 is an example of the present invention, and does not limit the present invention. That is, the present invention can be applied to all circuits that obtain a high voltage by switching an inductance element.

(Third Embodiment) FIG. 12 shows a third embodiment.

Assuming that the frequency of the clock oscillator 6 is the same in the driving circuit of the vibration wave actuator as shown in FIG. 3, the dynamic range is large when the speed is controlled by the frequency, and the resolution is increased when the control is performed by the pulse width.

In the third embodiment, the frequency is coarsely adjusted and the pulse width is finely adjusted in order to achieve a wide dynamic range and high resolution, or the two are appropriately combined for control.

FIG. 12 shows an operation flow in the case of such a control circuit. When speed control is performed by adjusting the drive frequency based on the pulse width (# 21), when an abnormal state signal is output from the state sensor (# 22), the drive frequency,
Immediately fix both pulse widths (# 23). Thereafter, the voltage is gradually lowered (# 24) and finally set to 0 (# 2).
5).

Thus, the vibration type actuator can be stopped smoothly, and the life can be extended without applying stress to the friction member.

In a general stabilized power supply, even if the power supply on the primary side is cut off due to the characteristics of the smoothing circuit, the voltage on the secondary side does not immediately decrease but gradually decreases with a certain time constant as shown in FIG.
Therefore, the operation of gradually lowering the voltage may simply be to cut off the power supply on the primary side. In the circuit as shown in FIG. 3, if the capacity of the electrolytic capacitor 27 is increased to some extent, the voltage remains the same as in FIG. Decreases gradually.

Therefore, in this case, it is sufficient to simply cut off the output of DC voltage power supply circuit 7. When the power is simply cut off, the determination as to whether the voltage in FIG. 1 has become 0 can be omitted.

In FIG. 11, the frequency and the pulse width are fixed, and then the voltage is lowered. However, instead of the voltage lowering operation, the pulse width is gradually lowered when a state sensor signal is input. May be performed. Note that the circuit in FIG. 3 is a circuit showing one example of the present invention and is not limited. That is, the present invention can be applied to all circuits that obtain a high voltage by switching an inductance element. Instead of lowering the voltage during the stop operation, the frequency may be gradually shifted to a higher frequency side.

[0088]

As described above, according to the present invention,
When the device using the vibration type actuator stops operating when it is not in a steady state, the vibration type actuator is prevented from suddenly stopping and the vibration amplitude is not increased, so that the life of the actuator is extended. Has an effect.

[Brief description of the drawings]

FIG. 1 is a flowchart showing the operation of a first embodiment of the present invention.

FIG. 2 is a sectional view of a vibration type actuator used in the embodiment of the present invention.

FIG. 3 is a drive circuit diagram used in the embodiment of the present invention.

FIG. 4 is a schematic diagram of an image forming apparatus using the vibration type driving device of the present invention.

FIG. 5 is a diagram showing a relationship between a pulse width and a current flowing through a primary side of a transformer in the circuit of FIG. 3;

FIG. 6 is a diagram showing a relationship between an applied voltage and a driving speed of a vibration type actuator.

FIG. 7 is a diagram illustrating a state of a voltage change when a power supply power supply of a vibration type actuator drive circuit having a capacitive element is cut off.

FIG. 8 is a diagram showing a relationship between a frequency of a pulse applied to a drive circuit of a vibration type actuator and a drive speed.

FIG. 9 is a diagram showing the operation of the first embodiment and the conventional example.

FIG. 10 is a flowchart showing the operation of the second embodiment.

FIG. 11 is a diagram showing the operation of the second embodiment and the conventional example.

FIG. 12 is a flowchart showing the operation of the third embodiment.

[Explanation of main symbols]

 DESCRIPTION OF SYMBOLS 1 Vibration body 2 Pressure spring 3 Stator 4 Piezoelectric element 5 DC power supply circuit 7 Pulse shaping circuit 8 Speed control circuit 9,10 180 ° phase shift circuit 19-22 MOSFET 23,24 Step-up transformer 25 Vibration type actuator 26 Speed detection Means 27 Electrolytic capacitor 28 Friction member 317-320 Image forming and transfer portion 342-344 Image transfer drum 333 Paper transport belt 348 Paper transport roller

(72) Inventor Jun Ito 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Akio Atsuta 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (19)

[Claims] 1. A vibration-type actuator, drive control means for controlling driving parameters of the vibration-type actuator, which is driven by being supplied with electric power from a power generation circuit, by a control circuit, and detecting a state of the apparatus to a predetermined state And a state detecting means for generating a signal when the state of the driving circuit is changed. The drive control means temporarily locks a driving parameter of the control circuit as soon as the signal of the state detecting means is detected. apparatus. 2. The drive control means according to claim 1, wherein the drive parameter of the vibration-type actuator controlled by the control circuit is a frequency of an alternating signal, and the frequency is fixed immediately upon detecting the state signal. A vibration type driving device characterized by the above-mentioned. 3. The method according to claim 1, wherein the drive parameter of the vibration-type actuator controlled by the control circuit is a voltage of an alternating signal, and the voltage command is fixed as soon as the signal of the state detecting means is detected. Vibration type driving device. 4. The power generation circuit according to claim 1, wherein the power generation circuit outputs an alternating signal by switching an inductance element, a pulse generation circuit that supplies a switching pulse to a switching element, and supplies power to the inductance element. A configuration including a power supply for supplying power, wherein the drive parameter of the vibration-type actuator controlled by the control circuit is a pulse width of the switching pulse, and the pulse width is fixed as soon as the signal of the state detection unit is detected. Characteristic vibration type driving device. 5. The power generation circuit according to claim 1, wherein the power generation circuit of the vibration type actuator outputs an alternating signal by switching an inductance element, a pulse generation circuit that supplies a switching pulse to a switching element, and an inductance. It is configured by a power supply for supplying power to the element, and the parameters of the vibration-type actuator controlled by the control circuit are a frequency and a pulse width of the switching pulse, and immediately upon detecting a state signal of the state detecting means, A vibration type driving device characterized by fixing a frequency and a pulse width. 6. The method according to claim 1, 2, 3, 4, or 5,
A vibration-type driving device, wherein the driving parameter by the driving control means is once locked, and then the voltage from the power supply is gradually reduced to zero finally. 7. The vibration type driving device according to claim 6, wherein the drive control means reduces the voltage stepwise by gradually reducing the pulse width. 8. The vibration type driving device according to claim 1, wherein the state detected by said state detecting means is a drop in power supply voltage. 9. The vibration type driving device according to claim 1, wherein the state detected by the state detection means is a decrease in the output of the vibration type actuator. . 10. The method of claim 1, 2, 3, 4, 5, 6, 7,
In 8 or 9, the vibration type driving device is provided in a housing having a door together with the high voltage section and the driving section, and the state detecting means detects the state of opening the door. 11. The method of claim 1, 2, 3, 4, 5, 6, 7,
An electrophotographic image forming apparatus, wherein one or a plurality of the vibration-type driving devices according to 8, 9, or 10 are used in a driving system. 12. An image forming apparatus according to claim 11, wherein the state detected by said state detecting means is an abnormal state of paper feeding in a printing unit. 13. An apparatus provided with a vibration-type actuator that obtains a driving force by applying a frequency signal to an electro-mechanical energy conversion element provided on an elastic body, wherein driving of the vibration-type actuator is stopped in an emergency. In this case, there is provided a control device for gradually shifting a driving state of the vibration type actuator to a stop state, wherein the apparatus is provided with a vibration type actuator. 14. The apparatus according to claim 13, further comprising state detecting means for detecting an operating state, an operating state, or a driving environment state of the apparatus, and the emergency detecting means when the state of the apparatus becomes a predetermined state. An apparatus provided with a vibration-type actuator, which performs a drive stop operation at the time. 15. The control device according to claim 13, wherein the control means gradually lowers a frequency signal applied to the electro-mechanical energy conversion element to shift the vibration-type actuator to a stop state. A device having a vibration type actuator. 16. An apparatus according to claim 15, wherein said control means gradually reduces a voltage level of a frequency signal applied to said electro-mechanical energy conversion element. . 17. A frequency signal having a frequency corresponding to the synchronization of the pulse signal to the electro-mechanical energy conversion element by an on / off operation of a switching unit that turns on / off in response to the pulse signal. A driving circuit for applying the driving signal, and the control unit gradually narrows the width of the pulse signal so as to perform the emergency driving stop operation. 18. The driving method according to claim 13, wherein the control unit gradually changes a driving state of the vibration-type actuator by gradually changing a frequency signal applied to the electro-mechanical energy conversion element. An apparatus provided with a vibration-type actuator, wherein the apparatus shifts to a stop state. 19. The apparatus according to claim 18, further comprising a vibration type actuator, wherein the frequency signal is gradually changed to a higher frequency to shift to a stop state.