1. An image forming apparatus comprising:
a heating member which includes a first region and a second region:
the second region locates in a predetermined position in the axial direction with respect to the first region;
a heating unit which is provided inside the heating member and which includes at least one of a first heating member for heating the first region and a second heating member for heating the second region;
a main control unit which carries out at least a first control mode and a second control mode;
wherein the first control mode performs control to drop the temperatures in the first and second regions from a fixing temperature by a predetermined temperature, with specific timing corresponding to a number of mediums on which an image is to be formed, at least once, while an image formation is being executed at the fixing temperature; and
wherein the second control mode turns off either the first heating member or the second heating member which has priority over the other member, the priority being determined according to the number of mediums on which an image is to be formed, with predetermined timing corresponding to the temperature supplied in the first control mode, when the image formation is completed.
2. The image forming apparatus according to claim 1, wherein the first region is disposed at the center of the heating member, and the second region is disposed at both ends of the first region, and when control to drop the temperatures has been performed once by the first control mode, the second heating member has priority over the first heating member in being turned off first.
3. The image forming apparatus according to claim 2, further comprising:
a third control mode which is carried out by the main control unit and which returns the temperatures in the first and second regions to the fixing temperature stepwise when the temperatures in the first and second regions have been lowered from the fixing temperature in the first control mode after the main control unit image formation is completed, wherein the temperature of the second heating member to which priority has been given by the first control mode is returned first.
4. The image forming apparatus according to claim 2, wherein the first region is disposed at the center of the heating member, and the second region is disposed at both ends of the first region,
wherein when control to drop the temperatures by the first control mode is not performed, the first heating member has priority over the second heating member in being turned off.
5. The image forming apparatus according to claim 1, further comprising:
a third control mode which is carried out by the main control unit and which returns the temperatures in the first and second regions to the fixing temperature stepwise when the temperatures in the first and second regions have been lowered from the fixing temperature in the first control mode after the main control unit image formation is completed, wherein the temperature of the first heating member or the second heating member to which priority has been given by the first control mode is returned first.
6. A method of controlling a heating unit, comprising:
(1) when an image formation is executed at a first temperature, performing control to drop the temperature of a heating member to a second temperature lower than the first temperature, with predetermined timing corresponding to a number of mediums on which an image is to be formed, at least once;
(2) when the image formation is completed, turning off the heating member with predetermined timing corresponding to the second temperature lowered from the first temperature stepwise, when the heating member composed of a first heating member and a second heating member is turned off, either the first heating member or the second heating member which has priority over the other heating member is turned off first, the priority being determined according to the number of mediums on which an image is to be formed; and
(3) after the image formation is completed, returning from the second temperature to the first temperature stepwise.
7. The method of controlling a heating unit according to claim 6, wherein
the timing with which the first and second heating members are turned off is determined by the second temperature obtained in dropping from the first temperature.
8. The method of controlling a heating unit according to claim 6, wherein
when the temperature of the heating member composed of a first heating member and a second heating member is recovered stepwise, shifting the timing with which the temperature in a first region heated by the first heating member rises from the timing with which the temperature in a second region heated by the second heating member rises.
9. The method of controlling a heating unit according to claim 8, wherein
the timing with which the first and second regions are raised is determined by the second temperature obtained in dropping from the first temperature.
10. The method of controlling a heating unit according to claim 6, wherein when the first heating member heats the center of the heating member, and the second heating member heats both ends of the heating member, and the step of turning off the heating member is performed at once,
the second heating member has priority over the first heating member in being turned off.
11. The method of controlling a heating unit according to claim 6, wherein the temperature of either the first heating member or the second heating member which has priority over the other heating member is returned first.
12. An image forming apparatus comprising:
a heating member includes a first heating member which heats a first region and a second heating member which heats a second region;
heating means for heating the heating member;
dropping means for dropping the heating member kept at a first temperature to a second temperature lower than the first temperature with predetermined timing corresponding to a number of mediums on which an image is to be formed;
OFF means for turning off, first, either the first heating member or the second heating member which has priority over the other heating member, the priority being determined according to the number of mediums on which an image is to be formed with predetermined timing according to the second temperature; and
recovering means for returning the heating member kept at the second temperature to the first temperature with predetermined timing corresponding to the number of mediums on which an image is to be formed, wherein the temperature of either the first heating member or the second heating member which has the priority is returned first.
13. The image forming apparatus according to claim 12, wherein the OFF means shifts the timing with which the first heating member is turned off from the timing with which the second heating member is turned off, when the heating member composed of the first heating member and the second heating member is turned off.
14. The image formation apparatus according to claim 13, wherein
the timing with which the first and second heating member are turned off is determined by the second temperature obtained when the dropping means drops the temperature from the first temperature.
15. The image formation apparatus according to claim 12, wherein the recovering means shifts the timing with which the temperature in the first region is raised from the timing with which the temperature in the second region is raised.
16. The image formation apparatus according to claim 15, wherein
the timing with which the temperatures in the first and second regions are raised is determined by the second temperature obtained when the dropping means drops the temperature from the first temperature.
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 chemical-mechanical polishing (CMP) method for polishing a substrate comprising: (a) contacting a surface of the substrate with an aqueous slurry comprising a low level of a suspended particulate abrasive material; (b) monitoring the TSS level in the slurry at one or more points in a CMP process using a suspended solids sensor; (c) maintaining a predetermined TSS level in the slurry by adjusting the level of the suspended particulate abrasive material in the slurry based upon the monitoring by the suspended solids sensor.
2. The method of claim 1 wherein the TSS level of the slurry is in the range of about 0.01 percent by weight to about 1.0 percent by weight.
3. The method of claim 1 wherein the TSS level of the slurry is in the range of about 0.05 percent by weight to about 0.6 percent by weight.
4. The method of claim 1 wherein the particulate abrasive material comprises a metal oxide.
5. The method of claim 4 wherein the metal oxide is cerium oxide.
6. The method of claim 1 wherein the TSS of the CMP slurry has a maximum TSS variability during the CMP process of less than about 20%.
7. The method of claim 1 wherein the TSS of the CMP slurry has a maximum TSS variability during the CMP process of less than about 10%.
8. A CMP apparatus comprising a movable platen adapted to hold a polishing pad on the platen, and a movable carrier assembly adapted to hold a substrate and to urge a surface of the substrate against the polishing pad; the apparatus also including a slurry delivery system adapted to contact an aqueous slurry comprising a low level of a suspended particulate abrasive material with the surface of the substrate; wherein during use the platen and carrier assembly are disposed in an opposed, parallel relation to one another with the pad and substrate therebetween; the delivery system being adapted to deposit at least a portion of the slurry between the pad and the surface of the substrate; the CMP slurry delivery system including at least one suspended solids sensor for measuring the TSS of the slurry.
9. The apparatus of claim 8 wherein the at least one suspended solids sensor comprises an in-line TSS monitoring device disposed within the slurry delivery system near an outlet for depositing the slurry onto the polishing pad.
10. A method of diluting a CMP slurry concentrate to a target TSS concentration comprising, monitoring the TSS of the slurry in real time using a suspended solids sensor and adding a diluents until the target TSS concentration is achieved.
11. The method of claim 10 wherein the target TSS concentration of the CMP slurry is in the range of about 0.01 percent by weight to about 1.0 percent by weight.
12. The method of claim 10 wherein the target TSS concentration of the CMP slurry is in the range of about 0.05 percent by weight to about 0.6 percent by weight.
13. The method of claim 10 wherein the particulate abrasive material comprises a metal oxide.
14. The method of claim 13 wherein the metal oxide is cerium oxide.