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US 2012/0070177 A1Published application
Power supply circuit for supplying power to electronic device such as image forming apparatus
AssigneeCanon Kabushiki Kaisha
InventorYasuhiko Okumura
Life of this patent
Estimating the term…
Abstract
A developing unit develops a latent image with a developing agent. A supply unit supplies, to the developing unit, a developing alternating current bias voltage with a waveform having a pulse period during which a rectangular wave is output and a blank period during which no rectangular wave is output. An input signal generation unit generates, as an input signal be supplied to a primary side of a transforming unit that forms the developing alternating current bias voltage, an input signal obtained by adding an additional pulse smaller in width than the rectangular wave in the pulse period at a timing to transit from the pulse period to the blank period.
Claims14
An image forming apparatus comprising:
- a developing unit which develops a latent image formed on a photosensitive member with a developing agent;
- a supply unit which supplies, to said developing unit, a developing alternating current bias voltage with a waveform having a pulse period during which a rectangular wave is output and a blank period during which no rectangular wave is output;
- and
- an input signal generation unit which generates, as an input signal be supplied to a primary side of a transforming unit that forms the developing alternating current bias voltage, an input signal obtained by adding an additional pulse smaller in width than the rectangular wave in the pulse period at a timing to transit from the pulse period to the blank period.
1 more element
A power supply circuit comprising:
- an alternating current voltage generation unit which outputs a blank pulse waveform having a pulse period during which a rectangular wave is output and a blank period during which no rectangular wave is output, said alternating current voltage generation unit including a full bridge circuit formed from a first switching unit having one end coupled to a voltage source, a second switching unit having one end coupled to the other end of the first switching unit and the other end coupled to ground, a third switching unit having one end coupled to the voltage source, and a fourth switching unit having one end coupled to the other end of the third switching unit and the other end coupled to ground;
- a transforming unit which receives the blank pulse waveform generated by said alternating current voltage generation unit, said transforming unit having a primary-side first terminal coupled to the other end of the first switching unit and the one end of the second switching unit, and a primary-side second terminal coupled to the other end of the third switching unit and the one end of the fourth switching unit;
- and
- a drive signal generation unit which outputs a first drive signal to driving terminals of the first switching unit and fourth switching unit to cause said alternating current voltage generation unit to output a rectangular wave of a first half cycle in the blank pulse waveform, and outputs a second drive signal to driving terminals of the second switching unit and third switching unit to cause said alternating current voltage generation unit to output a rectangular wave of a second half cycle in the blank pulse waveform,
- wherein the first drive signal has a first ON period during which both the first switching unit and the fourth switching unit are turned on, an OFF period during which both the first switching unit and the fourth switching unit are turned off, and a second ON period during which both the first switching unit and the fourth switching unit are turned on,
- the second drive signal has a first ON period during which both the second switching unit and the third switching unit are turned on, an OFF period during which both the second switching unit and the third switching unit are turned off, and a second ON period during which both the second switching unit and the third switching unit are turned on, and
- a length of the first ON period of the first drive signal and a length of the first ON period of the second drive signal are different from each other, a length of the OFF period of the first drive signal and a length of the OFF period of the second drive signal are different from each other, a length of the second ON period of the first drive signal and a length of the second ON period of the second drive signal are different from each other, and the length of the first ON period of the second drive signal is larger than the length of the first ON period of the first drive signal.
4 more elements
A power supply circuit comprising:
- an alternating current voltage generation unit which outputs a blank pulse waveform having a pulse period during which a rectangular wave is output and a blank period during which no rectangular wave is output, said alternating current voltage generation unit including a full bridge circuit formed from a first switching unit having one end coupled to a voltage source, a second switching unit having one end coupled to the other end of the first switching unit and the other end coupled to ground, a third switching unit having one end coupled to the voltage source, and a fourth switching unit having one end coupled to the other end of the third switching unit and the other end coupled to ground;
- a transforming unit which receives the blank pulse waveform generated by said alternating current voltage generation unit, said transforming unit having a primary-side first terminal coupled to the other end of the first switching unit and the one end of the second switching unit, and a primary-side second terminal coupled to the other end of the third switching unit and the one end of the fourth switching unit;
- and
- a drive signal generation unit which outputs a first drive signal to driving terminals of the first switching unit and fourth switching unit to cause said alternating current voltage generation unit to output a rectangular wave of a first half cycle in the blank pulse waveform, outputs a second drive signal to driving terminals of the second switching unit and third switching unit to cause said alternating current voltage generation unit to output a rectangular wave of a second half cycle in the blank pulse waveform, and outputs a third drive signal to driving terminals of the second switching unit and third switching unit to transit the blank pulse waveform from the pulse period to the blank period,
- wherein the third drive signal has an OFF period during which both the second switching unit and the third switching unit are turned off, and an ON period during which both the second switching unit and the third switching unit are turned on, the first drive signal has a first ON period during which both the first switching unit and the fourth switching unit are turned on, and an OFF period during which both the first switching unit and the fourth switching unit are turned off, and the second drive signal has a first ON period during which both the second switching unit and the third switching unit are turned on, and an OFF period during which both the second switching unit and the third switching unit are turned off, and
- wherein a length of the first ON period of the first drive signal, a length of the first ON period of the second drive signal, and a length of the OFF period of the third drive signal are different from each other, and a length of the OFF period of the first drive signal, a length of the OFF period of the second drive signal, and a length of the ON period of the third drive signal are different from each other.
3 more elements
An image forming apparatus comprising:
- a power supply circuit;
- a developing member to which a blank pulse waveform supplied from said power supply circuit is applied;
- an image carrier which bears an electrostatic latent image that is developed with a developing agent supplied from said developing member;
- and
- a transferring member which transfers a developing agent image from the image carrier onto a printing medium,
- said power supply circuit including:
- an alternating current voltage generation unit which outputs a blank pulse waveform having a pulse period during which a rectangular wave is output and a blank period during which no rectangular wave is output, said alternating current voltage generation unit including a full bridge circuit formed from a first switching unit having one end coupled to a voltage source, a second switching unit having one end coupled to the other end of the first switching unit and the other end coupled to ground, a third switching unit having one end coupled to the voltage source, and a fourth switching unit having one end coupled to the other end of the third switching unit and the other end coupled to ground;
- a transforming unit which receives the blank pulse waveform generated by said alternating current voltage generation unit, said transforming unit having a primary-side first terminal coupled to the other end of the first switching unit and the one end of the second switching unit, and a primary-side second terminal coupled to the other end of the third switching unit and the one end of the fourth switching unit;
- and
- a drive signal generation unit which outputs a first drive signal to driving terminals of the first switching unit and fourth switching unit to cause said alternating current voltage generation unit to output a rectangular wave of a first half cycle in the blank pulse waveform, and outputs a second drive signal to driving terminals of the second switching unit and third switching unit to cause said alternating current voltage generation unit to output a rectangular wave of a second half cycle in the blank pulse waveform,
- wherein the first drive signal has a first ON period during which both the first switching unit and the fourth switching unit are turned on, an OFF period during which both the first switching unit and the fourth switching unit are turned off, and a second ON period during which both the first switching unit and the fourth switching unit are turned on,
- the second drive signal has a first ON period during which both the second switching unit and the third switching unit are turned on, an OFF period during which both the second switching unit and the third switching unit are turned off, and a second ON period during which both the second switching unit and the third switching unit are turned on, and
- a length of the first ON period of the first drive signal and a length of the first ON period of the second drive signal are different from each other, a length of the OFF period of the first drive signal and a length of the OFF period of the second drive signal are different from each other, a length of the second ON period of the first drive signal and a length of the second ON period of the second drive signal are different from each other, and the length of the first ON period of the second drive signal is larger than the length of the first ON period of the first drive signal.
10 more elements
An image forming apparatus comprising:
- a power supply circuit;
- a developing member to which a blank pulse waveform supplied from said power supply circuit is applied;
- an image carrier which bears an electrostatic latent image that is developed with a developing agent supplied from said developing member;
- and
- a transferring member which transfers a developing agent image from the image carrier onto a printing medium,
- said power supply circuit including:
- an alternating current voltage generation unit which outputs a blank pulse waveform having a pulse period during which a rectangular wave is output and a blank period during which no rectangular wave is output, said alternating current voltage generation unit including a full bridge circuit formed from a first switching unit having one end coupled to a voltage source, a second switching unit having one end coupled to the other end of the first switching unit and the other end coupled to ground, a third switching unit having one end coupled to the voltage source, and a fourth switching unit having one end coupled to the other end of the third switching unit and the other end coupled to ground;
- a transforming unit which receives the blank pulse waveform generated by said alternating current voltage generation unit, said transforming unit having a primary-side first terminal coupled to the other end of the first switching unit and the one end of the second switching unit, and a primary-side second terminal coupled to the other end of the third switching unit and the one end of the fourth switching unit;
- and
- a drive signal generation unit which outputs a first drive signal to driving terminals of the first switching unit and fourth switching unit to cause said alternating current voltage generation unit to output a rectangular wave of a first half cycle in the blank pulse waveform, outputs a second drive signal to driving terminals of the second switching unit and third switching unit to cause said alternating current voltage generation unit to output a rectangular wave of a second half cycle in the blank pulse waveform, and outputs a third drive signal to driving terminals of the second switching unit and third switching unit to transit the blank pulse waveform from the pulse period to the blank period,
- wherein the third drive signal has an OFF period during which both the second switching unit and the third switching unit are turned off, and an ON period during which both the second switching unit and the third switching unit are turned on, the first drive signal has a first ON period during which both the first switching unit and the fourth switching unit are turned on, and an OFF period during which both the first switching unit and the fourth switching unit are turned off, and the second drive signal has a first ON period during which both the second switching unit and the third switching unit are turned on, and an OFF period during which both the second switching unit and the third switching unit are turned off, and
- wherein a length of the first ON period of the first drive signal, a length of the first ON period of the second drive signal, and a length of the OFF period of the third drive signal are different from each other, and a length of the OFF period of the first drive signal, a length of the OFF period of the second drive signal, and a length of the ON period of the third drive signal are different from each other.
9 more elements
Dependencies are inferred from the claim text.