Electricity: motive power systems – Impact – mechanical shock – or vibration-producing motors
Reexamination Certificate
1999-07-28
2001-12-25
Ramirez, Nestor (Department: 2834)
Electricity: motive power systems
Impact, mechanical shock, or vibration-producing motors
C318S128000, C318S116000, C310S316010
Reexamination Certificate
active
06333609
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a drive control device of a vibration type motor, a device having the vibration type motor, and an image forming apparatus such as an electrophotographic printer, copying machine, or facsimile apparatus.
2. Related Background Art
Conventionally, a vibration type motor uses a vibration member. This vibration member is formed by adhering, with an adhesive, piezoelectric elements serving as electromechanical energy conversion elements to one surface of, e.g., a metal ring-like elastic member. Two standing waves are excited on the elastic member by applying alternative voltages having different phases to a driving piezoelectric element group formed on the piezoelectric elements, and generate a travelling vibration wave as a bending vibration by synthesizing these standing waves.
A member in, e.g., a ring shape, is pressed against the other surface of the elastic member via a press means, such as a spring. This member and an elastic member relatively move by frictional driving by the travelling vibration wave generated on the elastic member.
A the driving control device for controlling drive of the vibration type motor comprises a driving pulse generator for generating a driving pulse, and an alternative voltage generator, including a transformer, for generating alternative voltages having different phases applied to the piezoelectric element group in accordance with the driving pulse.
Since the vibration type motor has a high rotational precision and high resistance to transient load variations, a device using this vibration type motor as a driving source is advantageous in terms of color misregistration, pitch irregularity, paper feed shock, and the like. Thus, this device is proposed to be used as a driving device for a photosensitive drum of each color in an electrophotography color image forming apparatus, and a driving device for a driving roller for driving an endless transfer member convey belt, which sequentially conveys a transfer member to the transfer position of the photosensitive drum of each color.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a drive control device of a vibration type motor, capable of detecting that the transformer of the drive control device becomes unusual, and preventing the influence of the unusual transformer on the vibration type motor or a driving circuit, a device having the vibration type motor, and an image forming apparatus.
One aspect of the application is to provide a drive control device of a vibration type motor in which a periodic voltage is applied to an electro-mechanical energy conversion element to vibrate a vibration member, thereby obtaining a driving force, comprising a monitor circuit for monitoring information about the rotational speed of the vibration type motor, a frequency control circuit for comparing information about the rotational speed monitored by the monitor circuit with information about a target speed, and increasing/decreasing a driving frequency in order to shift the speed of the motor to the target speed, a driving circuit for generating a periodic voltage having a frequency corresponding to the frequency controlled by the control circuit, and a stop circuit for placing the driving circuit in an inoperative state when the difference between the target speed and the speed of the motor is not reduced even by increasing/decreasing the frequency by the control circuit.
One aspect of the application is to provide a drive control device of a vibration type motor in which a periodic voltage is applied to an electro-mechanical energy conversion element to vibrate a vibration member, thereby obtaining a driving force, comprising a transformer circuit including a transformer for generating the periodic voltage as an output from a secondary side, a determination circuit for determining whether the transformer becomes unusual, and a stop circuit for stopping driving of the motor when the determination circuit determines that the transformer becomes unusual.
One aspect of the application is to provide a drive control device of a vibration type motor in which a periodic voltage is applied to an electro-mechanical energy conversion element to vibrate a vibration member, thereby obtaining a driving force, comprising an encoder connected to the vibration type motor, a feedback control system, the control system having a first comparator for comparing an output from the encoder with target speed data, and a feedback circuit for increasing/decreasing a driving frequency in accordance with an output from the comparator in order to shift the speed of the motor to the target speed, a driving circuit connected to the feedback control system to generate a periodic voltage having a frequency corresponding to the frequency determined by feedback control system, a second comparator for comparing the frequency determined by the feedback system with a limit value, and when the frequency reaches the limit value, outputting a signal representing that the frequency has reached the limit value, and a stop circuit connected to the second comparator to place the driving circuit in an inoperative state.
One aspect of the application is to provide a printer apparatus having the above drive control device.
The above and other objects, features, and advantages of the present invention will be apparent from the following description in conjunction with the accompanying drawings.
REFERENCES:
patent: 4951168 (1990-08-01), Harrison
patent: 5739724 (1998-04-01), Alexandre et al.
patent: 6049156 (2000-04-01), Yamamoto et al.
patent: 6114818 (2000-09-01), Ohtsubo et al.
Fukusaka Tetsuro
Kawase Michio
Otsubo Toshihiko
Suzuki Kazuyoshi
Watanabe Takahiro
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Jones Judson H.
Ramirez Nestor
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