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US 7,031,040 B2Granted
Optical scanning apparatus, optical writing apparatus, image forming apparatus, and method of driving vibration mirror
AssigneeRicoh Company, Ltd.
InventorsMitsumi Fujii, Eiji Mochizuki
Life of this patent
Estimating the term…
Abstract
An optical scanning apparatus includes a vibration mirror having a mirror surface that reflects an optical beam. A pair of torsion beams swingably support the mirror. The mirror is vibrated in a sealed space whose pressure is adjusted such that a characteristic of the mirror falls within a predetermined range.
Claims23
An optical scanning apparatus, comprising:
- a vibration mirror including driving electrodes;
- and
- a driving part that applies a driving pulse to the driving electrodes of said vibration mirror,
- said vibration mirror including:
- a mirror substrate having free ends;
- two beams swingably supporting said mirror substrate;
- and
- movable electrodes formed on the free ends of said mirror substrate;
- and
- wherein the driving electrodes are provided at positions corresponding to said movable electrodes so as to generate an electrostatic torque for vibrating said mirror substrate, and
- wherein a cycle of the driving pulse is set such that said mirror substrate is vibrated at a frequency that is higher than a resonance point of a resonance frequency band of said vibration mirror.
8 more elements
An optical scanning apparatus, comprising:
- a vibration mirror;
- and
- a driving part,
- said vibration mirror including:
- a mirror substrate having free ends;
- two beams swingably supporting said mirror substrate;
- movable electrodes formed on the free ends of said mirror substrate;
- two first driving electrodes that generate an electrostatic torque for vibrating said mirror substrate;
- and
- two second driving electrodes that are provided to overlap with said respective first driving electrodes in a vibration direction of said mirror substrate and that generate an electrostatic torque for vibrating said mirror substrate,
- said driving part being adapted to apply a first driving pulse to said first driving electrodes, a second driving pulse to one of said second driving electrodes, and a third driving pulse to the other of said second driving electrodes,
- wherein cycles and phases of the first, second and third driving pulses are set such that said mirror substrate is vibrated at a frequency that is higher than a resonance point of a resonance frequency zone of said vibration mirror.
9 more elements
A method of driving a vibration mirror including:
- a mirror substrate having free ends;
- two beams swingably supporting said beams;
- movable electrodes formed on the free ends of said mirror substrate;
- and driving electrodes that are provided at positions corresponding to said movable electrodes and that generate an electrostatic torque for vibrating said mirror substrate, said method comprising the steps of:
- setting a cycle of a driving pulse such that said mirror substrate is vibrated at a frequency higher than a resonance point of a resonance frequency band;
- and
- applying the driving pulse to said driving electrodes.
4 more elements
A method of driving a vibration mirror including:
- a mirror substrate;
- two beams swingably supporting said mirror substrate;
- movable electrodes formed on free ends of said mirror substrate;
- two first driving electrodes that generate electrostatic torque for vibrating said mirror substrate;
- and two second driving electrodes that are provided to overlap with said respective first driving electrodes in a vibration direction of said mirror substrate and that generate an electrostatic torque for vibrating said mirror substrate, said method comprising the steps of:
- setting cycles and phases of a first driving pulse, a second driving pulse, and a third driving pulse such that the mirror substrate is vibrated at a frequency that higher than a resonance point of a resonance frequency band of said mirror substrate;
- and
- applying the first driving pulse to the first driving electrodes, the second driving pulse to one of the second driving electrodes, and the third driving pulse to the other of the second electrodes.
5 more elements
An optical writing apparatus for scanning an image carrier with an optical light beam modulated with a recording signal, said optical writing apparatus comprising:
- an optical scanning apparatus;
- and
- an incident part,
- said optical scanning apparatus including:
- a vibration mirror including driving electrodes;
- and
- a driving part that applies a driving pulse to the driving electrodes of said vibration mirror,
- said vibration mirror including:
- a mirror substrate having a mirror surface and free ends;
- two beams swingably supporting said mirror substrate;
- and
- movable electrodes formed on the free ends of said mirror substrate;
- wherein the driving electrodes are provided at positions corresponding to said movable electrodes so as to generate an electrostatic torque for vibrating said mirror substrate, and
- wherein a cycle of the driving pulse is set such that said mirror substrate is vibrated at a frequency that is in a resonance frequency band of said vibration mirror and is higher than a resonance point, and
- said incident part being disposed to cause the optical light beam modulated with the recording signal to be incident on the mirror surface of the mirror substrate of the vibration mirror of the optical scanning apparatus.
12 more elements
An optical writing apparatus for scanning an image carrier with an optical light beam modulated with a recording signal, said optical writing apparatus comprising:
- an optical scanning apparatus;
- and
- an incident part,
- said optical apparatus including:
- a vibration mirror;
- and
- a driving part,
- said vibration mirror including:
- a mirror substrate having free ends and a mirror surface;
- two beams swingably supporting said mirror substrate;
- movable electrodes formed on the free ends of said mirror substrate;
- two first driving electrodes that generate an electrostatic torque for vibrating said mirror substrate;
- and
- two second driving electrodes that are provided to overlap with said respective first driving electrodes in a vibration direction of said mirror substrate and that generate an electrostatic torque for vibrating said mirror substrate,
- said driving part being adapted to apply a first driving pulse to said first driving electrodes, a second driving pulse to one of said second driving electrodes, and a third driving pulse to the other of said second driving electrodes,
- wherein cycles and phases of the first, second and third driving pulses are set such that said mirror substrate is vibrated at a frequency that is higher than a resonance point of a resonance frequency zone of said vibration mirror, and
- said incident part causing the optical light beam modulated with the recording signal to be incident on a mirror surface of the mirror substrate of the vibration mirror of the optical scanning apparatus.
14 more elements
An image forming apparatus, comprising:
- an image carrier;
- an optical writing apparatus that forms an electrostatic latent image on said image carrier by scanning said image carrier with an optical light beam modulated with a recording signal;
- a developing part that develops with toner the electrostatic latent image formed on said image carrier;
- a transfer part that transfers a developed toner image on a transfer medium;
- and
- a fixing part that fixes a transferred toner image to the transfer medium,
- said optical writing apparatus including:
- an optical scanning apparatus;
- and
- an incident part,
- said optical scanning apparatus including:
- a vibration mirror including driving electrodes;
- and
- a driving part that applies a driving pulse to the driving electrodes of said vibration mirror,
- said vibration mirror including:
- a mirror substrate having a mirror surface and fee ends;
- two beams swingably supporting said mirror substrate;
- and
- movable electrodes formed on the free ends of said mirror substrate;
- wherein the driving electrodes are provided at positions corresponding to said movable electrodes so as to generate an electrostatic torque for vibrating said mirror substrate, and
- wherein a cycle of the driving pulse is set such that said mirror substrate is vibrated at a frequency that is higher than a resonance point of a resonance frequency band of said vibration mirror, and
- said incident part being disposed to cause the optical light beam modulated with the recording signal to be incident on the mirror surface of the mirror substrate of the vibration mirror of the optical scanning apparatus.
19 more elements
An image forming apparatus, comprising:
- an image carrier;
- an optical writing apparatus that forms an electrostatic latent image on said image carrier by scanning said image carrier with an optical light beam modulated with a recording signal;
- a developing part that develops with toner the electrostatic latent image formed on said image carrier;
- a transfer part that transfers a developed toner image on a transfer medium;
- and
- a fixing part that fixes a transferred toner image to the transfer medium,
- said optical writing apparatus including:
- an optical scanning apparatus;
- and
- an incident part,
- said optical apparatus including:
- a vibration mirror;
- and
- a driving part,
- said vibration mirror including:
- a mirror substrate having free ends and a mirror surface;
- two beams swingably supporting said mirror substrate;
- movable electrodes formed on the free ends of said mirror substrate;
- two first driving electrodes that generate an electrostatic torque for vibrating said mirror substrate;
- and
- two second driving electrodes that are provided to overlap with said respective first driving electrodes in a vibration direction of said mirror substrate and that generate an electrostatic torque for vibrating said mirror substrate,
- said driving part being adapted to apply a first driving pulse to said first driving electrodes, a second driving pulse to one of said second driving electrodes, and a third driving pulse to the other of said second driving electrodes,
- wherein cycles and phases of the first, second and third driving pulses are set such that said mirror substrate is vibrated at a frequency that is higher than a resonance point of a resonance frequency zone of said vibration mirror, and
- said incident part being adapted to cause the optical light beam modulated with the recording signal to be incident on the mirror surface of the mirror substrate of the vibration mirror of the optical scanning apparatus.
21 more elements
Dependencies are inferred from the claim text.