1. An electrosurgical apparatus comprising:
a high frequency power generation section which generates high frequency power to be applied to a living tissue;
a voltage detection section which detects a voltage of the high frequency power;
a current detection section which detects a current of the high frequency power;
an impedance computation section which computes the impedance between holding members for grasping the living tissue, on the basis of the voltage and the current;
a detection section which detects that a value of the impedance computed by the impedance computation section exceeds a predetermined threshold value;
a waveform generation circuit which generates a timing signal according to a first frequency of the high frequency power to be generated from the high frequency power generation section or a timing signal according to a second frequency higher than the first frequency and outputs the generating timing signal; and
a control section which performs control for switching the timing signal to be outputted from the waveform generation circuit from the timing signal according to the first frequency to the timing signal according to the second frequency based on a result obtained by the detection section.
2. The electrosurgical apparatus according to claim 1, wherein when the control section detects that the impedance has exceeded the predetermined threshold value and the frequency is at the maximum, the control section performs control for stopping or substantially stopping output of the high frequency power on the high frequency power generation section.
3. The electrosurgical apparatus according to claim 1, wherein when the control section detects that the impedance has exceeded the predetermined threshold value and the frequency is at the maximum, the control section performs control for outputting high frequency power having the maximum frequency for a predetermined time period on the high frequency power generation section.
4. The electrosurgical apparatus according to claim 1, wherein when the impedance exceeds the predetermined threshold value, the control section performs control for increasing the frequency stepwise in the range from 350 kHz to 5 MHz on the high frequency power generation section.
5. A method of controlling an electrosurgical apparatus comprising:
a step of generating high frequency power to be applied to a living tissue by a high frequency power generation section;
a step of detecting a voltage of the high frequency power by a first detection section;
a step of detecting a current of the high frequency power by a second detection section;
a step of computing the impedance between holding members for grasping the living tissue, on the basis of the voltage and the current by an impedance computation section;
a step of detecting that a value of the impedance computed by the impedance computation section exceeds a predetermined threshold value by a third detection section;
a step of generating a timing signal according to a first frequency of the high frequency power to be generated from the high frequency power generation section or a timing signal according to a second frequency higher than the first frequency and outputting the generated timing signal by a waveform generation circuit; and
a step of switching the timing signal to be outputted from the waveform generation circuit from the timing signal according to the first frequency to the timing signal according to the second frequency based on a result obtained by a third detection section by control of a control section.
6. The method of controlling an electro surgical apparatus according to claim 5, further comprising a step of stopping or substantially stopping output of the high frequency power when a situation where the impedance has exceeded the predetermined threshold value and where the frequency is at the maximum value is detected.
7. The method of controlling an electro surgical apparatus according to claim 5, further comprising a step of outputting high frequency power having the maximum frequency for a predetermined time period when a situation where the impedance has exceeded the predetermined threshold value and where the frequency is at the maximum value is detected.
8. The method of controlling an electro surgical apparatus according to claim 5, wherein when the impedance exceeds the predetermined threshold value, the frequency is increased stepwise in the range from 350 kHz to 5 MHz.
9. An electrosurgical apparatus comprising:
high frequency power generation means which generates high frequency power to be applied to a living tissue;
voltage detection means which detects a voltage of the high frequency power;
current detection means which detects a current of the high frequency power;
impedance computation means which computes the impedance between holding members for grasping the living tissue, on the basis of the voltage and the current;
detection means which detects that a value of the impedance computed by the impedance computation means exceeds a predetermined threshold value;
waveform generation means which generates a timing signal according to a first frequency of the high frequency power to be generated from the high frequency power generation means or a timing signal according to a second frequency higher than the first frequency and outputs the generated timing signal; and
control means which performs control for switching the timing signal to be outputted from the waveform generation means from the timing signal according to the first frequency to the timing signal according to the second frequency based on a result obtained by the detection means.
10. The electrosurgical apparatus according to claim 1, wherein the frequency of the high frequency power generated from the high frequency power generation section is increased stepwise, when the value of the impedance exceeds the predetermined threshold value.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A printing system sheet feeder apparatus comprising:
a sheet stack comprising two or more sheets of media stacked in a vertical position which includes a top sheet and a sheet directly below the top sheet, each sheet including a leading edge and a trailing edge;
a front nudger roll positioned near the leading edge of the top sheet of the sheet stack, capable of advancing the top sheet;
a separation nip aligned with the front nudger roll and capable of receiving the top sheet advanced by the front nudger roll and advancing the top sheet in a direction away from the front nudger; and
a rear nudger roll, the rear nudger roll being positioned near the trailing edge of the top sheet and capable of advancing the sheet directly below the top sheet while the top sheet is being advanced by the front nudger roll andor separation nip.
2. The apparatus of claim 1, further comprising:
a take-away nip aligned with the separator nip and cable of receiving the top sheet advanced by the separation nip, the take-away nip advancing the top sheet to a sheet path independent of the sheet feeder apparatus and the take-away nip capable of advancing the sheet at speeds greater that the speed of the separation nip.
3. The apparatus of claim 2, the take away nip further comprising:
a drive roll; and
an idler roll.
4. The apparatus of claim 1, further comprising:
a sheet stack tray comprising an elevator lift plate to advance the sheet stack in a vertical direction;
a sheet stack trail edge guide for controlling the lateral position of the sheet stack in one direction;
a sheet stack lead edge guide for controlling the lateral position of the sheet stack in another direction; and
a sheet stack height sensor.
5. The apparatus of claim 4, wherein the rear nudger roll is adjustably mounted to the sheet stack trailing edge guide.
6. The apparatus of claim 4, wherein the rear nudger roll is fixed to the sheet stack trailing edge guide.
7. The apparatus of claim 1, further comprising:
a belt drive mechanism integrated with the front nudger roll and the separation nip, wherein the front nudger roll and the separation nip rotate in a direction that advances the top sheet in a direction oriented from the front nudger roll to the separation nip.
8. The apparatus of claim 1, the separation nip further comprising:
a mechanically driven feed roll; and
a retard roll, the feed roll and the retard roll aligned to advance one sheet advanced from the front nudger.
9. The apparatus of claim 1, the rear nudger roll further comprising:
a mechanically driven roll.
10. The apparatus of claim 1, the rear nudger roll further comprising:
a D-roll segment to advance the top sheet.
11. The apparatus of claim 1, wherein the rear nudger roll axis of rotation is located a distance X1 from the trailing edge of the sheet stack, and the separation nip axis of rotation is located a distance X2 from the leading edge of the sheet stack, and the front nudger roll engages and advances the top sheet in a direction towards the separation nip.
12. The apparatus of claim 11, wherein the distance X1 is less than distance X2.
13. The apparatus of claim 12, wherein the distance X1 is approximately equal to distance X2.
14. The apparatus of claim 11, wherein the rear nudger roll engages and advances the sheet directly below the top sheet in a direction towards the separation nip and for a distance X1.
15. The apparatus of claim 14, further comprising:
a sheet acquisition sensor aligned with the separation nip to detect the leading edge of a sheet advancing from the separation nip.
16. The apparatus of claim 1, further comprising:
a nearly zero-rated spring, wherein the rear nudger roll is vertically suspended above the sheet stack by the spring and the rear nudger roll engages the sheet directly below the top sheet.
17. A method of feeding sheets to a printing system comprising:
starting a sheet feed cycle;
applying a tangential force near the leading edge of a top sheet of a sheet stack;
driving the top sheet into a separation nip;
removing the said force near the leading edge of the top sheet after the top sheet leading edge passes through the separation nip;
driving the top sheet with the separation nip to a take-away nip, while simultaneously applying a tangential force near the trailing edge of a next sheet directly below the top sheet; and
removing the tangential force from the next sheet after driving the next sheet a predetermined distance towards the separation nip.
18. A xerographic printing system comprising:
one or more sheet feeder apparatuses, each sheet feeder apparatus comprising:
a sheet stack comprising two or more sheets of media stacked in a vertical position which includes a top sheet and a sheet directly below the top sheet, each sheet including a leading edge and a trailing edge;
a front nudger roll positioned near the leading edge of the top sheet of the sheet stack, capable of advancing the top sheet;
a separation nip aligned with the front nudger roll and capable of receiving the top sheet advanced by the front nudger roll and advancing the top sheet in a direction away from the front nudger; and
a rear nudger roll, the rear nudger roll being positioned near the trailing edge of the top sheet and capable of advancing the sheet directly below the top sheet while the top sheet is being advanced by the front nudger roll andor separation nip.
19. A xerographic printing system according to claim 18, further comprising:
a sheet stack comprising two or more sheets of media stacked in a vertical position which includes a top sheet and a sheet directly below the top sheet, each sheet including a leading edge and a trailing edge;
a front nudger roll positioned near the leading edge of the top sheet of the sheet stack, capable of advancing the top sheet;
a separation nip aligned with the front nudger roll and capable of receiving the top sheet advanced by the front nudger roll and advancing the top sheet in a direction away from the front nudger;
a rear nudger roll, the rear nudger roll being positioned near the trailing edge of the top sheet and capable of advancing the sheet directly below the top sheet while the top sheet is being advanced by the front nudger roll andor separation nip; and
a take-away nip aligned with the separator nip and cable of receiving the top sheet advanced by the separation nip, the take-away nip advancing the top sheet to a sheet path independent of the sheet feeder apparatus and the take-away nip capable of advancing the sheet at speeds greater than the speed of the separation nip.
20. A xerographic printing system according to claim 19, further comprising:
one or more printing modules
one or more feed modules; and
one or more finishing modules.