1. A drum brake including a plate on which a first brake having a friction lining and a second brake shoe having a friction lining are mounted, application means for applying a force moves said first and second brakes shoes against a wheel drum in response to a braking command, and resilient return means for spacing said first and second brake shoes apart from the wheel drum when braking ceases, said first and second brake shoes each being mounted to respectively slide along an essentially radial axis between first and second guide walls secured to said plate, said application means for moving said first and second brake shoes bearing against end exerting a substantially radial force on an inside wall of said first and second brake shoes through a lever arrangement including a first lever having a first end for receiving the braking command and a second end that is located on said plate to define a first hinge and a second lever having a first end for receiving said braking command and a second end that is located on said plate to define a second hinge, a first control bar attached to said first lever through a first hinge pin and a second control bar attached to said second lever through a second hinge pin, said radial force being derived from the braking command said first and second levers respectively pivoting about said first and second hinges and said first and second control bars respectively pivoting about said first and second hinge pins such that said first and second brake shoes move along a radial plane with respect to said first and second guide walls.
2. The drum brake according to claim 1, wherein a leverage ratio of the braking command and the radial force lies in the range 2 to 3.
3. The drum brake as recited in claim 2 wherein said first brake shoe has a first segment and a second segment that are spaced apart from each other and said first control bar has a first end that engages an inside face on said first segment thereof and a second end that engages an inside face on said second segment thereof and where said second brake shoe has a first segment and a second segment that are spaced apart from each other and said second control bar has a first end that engages an inside face on said first segment of said second brake shoe and a second end that engages an inside face on said second segment of said second brake shoe such that the radial force derived from the braking force is uniformily applied through the first and second brake shoes to effect a brake application.
4. The drum brake according to claim 3, wherein the drum brake is organized so that an axis of the reaction force is offset relative to an axis of the inlet force.
5. The drum brake as recited in claim 3 wherein a zone at which the first and second control bars respectively bear against the inside face of the first and second segments of said first and second shoes is situated about half-way between the ends of each segment.
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 method of measuring color-to-color registration in a multicolor marking platform, comprising:
a) marking a plurality of test pattern images on an image receiving member using a reference color separation station and a first color separation station over a process direction span in relation to a selected target media and a cyclic characteristic of the multicolor marking platform;
b) detecting each test pattern image on the image receiving member;
c) determining a first registration measurement associated with the first color separation in relation to the reference color separation for each test pattern image, wherein the first registration measurements provide one of process measurements and cross-process measurements for the first color separation; and
d) determining a first repeatable registration error pattern associated with the first color separation and the selected target media in relation to the cyclic characteristic based at least in part on the first registration measurements determined in c).
2. The method set forth in claim 1, further comprising:
e) marking the plurality of test pattern images on the image receiving member over a cross-process direction span in relation to the selected target media.
3. The method set forth in claim 2, further comprising:
f) averaging first registration measurements for test pattern images positioned in cross-process direction relation during the determining in d).
4. The method set forth in claim 2 wherein the process direction span for the marking in a) continues for a plurality of cycles in relation to the cyclic characteristic, further comprising:
f) averaging first registration measurements for test pattern images positioned in cyclic relation with respect to absolute cross-process direction for the cyclic characteristic during the determining in d).
5. The method set forth in claim 1 wherein each test pattern image is indicative of process direction registration and cross-process registration of the first color separation in relation to the reference color separation, further comprising:
e) determining a second registration measurement associated with the first color separation in relation to the reference color separation for each test pattern image, wherein the first and second registration measurements provide process and cross-process measurements for the first color separation; and
f) determining a second repeatable registration error pattern associated with the first color separation and the selected target media in relation to the cyclic characteristic based at least in part on the second registration measurements determined in e).
6. The method set forth in claim 1 wherein the plurality of test pattern images are arranged in at least one array, each array comprising at least one row extending along the process direction span and a plurality of columns extending along a cross-process direction span, a quantity of columns for each array based at least in part on a size dimension for the selected target media in relation to the process direction.
7. The method set forth in claim 6 wherein each array includes a plurality of rows extending along the process direction, a quantity of rows for each array based at least in part on a size dimension for the selected target media in relation to the cross-process direction.
8. The method set forth in claim 1 wherein the cyclic characteristic is cyclic in relation to marking each sheet of the selected target media.
9. The method set forth in claim 1 wherein the cyclic characteristic is cyclic in relation to a revolution of a belt associated with the marking platform and adapted to transfer marking material from the color separation stations to the selected target media.
10. The method set forth in claim 9 wherein the cyclic characteristic is cyclic in relation to marking a plurality of consecutive sheets of the selected target media marked during each revolution of the belt.
11. The method set forth in claim 1, further comprising:
e) using a second color separation station and a third color separation station for the marking of the plurality of test pattern in a);
f) determining a second registration measurement associated with the second color separation in relation to the reference color separation for each test pattern image, wherein the second registration measurements provide one of process measurements and cross-process measurements for the second color separation;
g) determining a second repeatable registration error pattern associated with the second color separation and the selected target media in relation to the cyclic characteristic based at least in part on the second registration measurements determined in f);
h) determining a third registration measurement associated with the third color separation in relation to the reference color separation for each test pattern image, wherein the third registration measurements provide one of process measurements and cross-process measurements for the third color separation; and
i) determining a third repeatable registration error pattern associated with the third color separation and the selected target media in relation to the cyclic characteristic based at least in part on the third registration measurements determined in h).
12. The method set forth in claim 11 wherein each test pattern image is indicative of process direction registration and cross-process registration of the first, second, and third color separations in relation to the reference color separation, further comprising:
j) determining a fourth registration measurement associated with the first color separation in relation to the reference color separation for each test pattern image, wherein the first and fourth registration measurements provide process and cross-process measurements for the first color separation;
k) determining a fourth repeatable registration error pattern associated with the first color separation and the selected target media in relation to the cyclic characteristic based at least in part on the fourth registration measurements determined in j);
l) determining a fifth registration measurement associated with the second color separation in relation to the reference color separation for each test pattern image, wherein the second and fifth registration measurements provide process and cross-process measurements for the second color separation;
m) determining a fifth repeatable registration error pattern associated with the second color separation and the selected target media in relation to the cyclic characteristic based at least in part on the fifth registration measurements determined in l);
n) determining a sixth registration measurement associated with the third color separation in relation to the reference color separation for each test pattern image, wherein the third and sixth registration measurements provide process and cross-process measurements for the third color separation; and
o) determining a sixth repeatable registration error pattern associated with the third color separation and the selected target media in relation to the cyclic characteristic based at least in part on the sixth registration measurements determined in n).
13. The method set forth in claim 1 wherein the image receiving member includes one or more sheets of the selected target media.
14. An apparatus for measuring color-to-color registration in a multicolor marking platform, comprising:
a marking engine with a reference color separation station and a first color separation station;
a controller in operative communication with the marking engine to selectively mark a plurality of test pattern images on an image receiving member over a process direction span using the reference color separation station and the first color separation station in relation to a selected target media and a cyclic characteristic of the multicolor marking platform;
a sensor in operative communication with the controller to detect each test pattern image on the image receiving member;
a color registration measurement logic in operative communication with the sensor and controller to determine a first registration measurement associated with the first color separation in relation to the reference color separation for each test pattern image, the first registration measurements providing one of process measurements and cross-process measurements for the first color separation; and
a repeatable registration error determining logic in operative communication with the color registration measurement logic and the controller to determine a first repeatable registration error pattern associated with the first color separation and the selected target media in relation to the cyclic characteristic based at least in part on the first registration measurements determined by the color registration measurement logic.
15. The apparatus set forth in claim 14 wherein the controller selectively marks the plurality of test pattern images on the image receiving member over a cross-process direction span in relation to the selected target media.
16. The apparatus set forth in claim 15 wherein the repeatable registration error determining logic averages the first registration measurements for test pattern images positioned in cross-process direction relation during the determining of the first repeatable registration error pattern.
17. The apparatus set forth in claim 15 wherein the controller selectively marks the plurality of test pattern images in the process direction span for a plurality of cycles in relation to the cyclic characteristic; and
wherein the repeatable registration error determining logic averages the first registration measurements for test pattern images positioned in cyclic relation with respect to absolute cross-process direction for the cyclic characteristic during the determining of the first repeatable registration error pattern.
18. The apparatus set forth in claim 14 wherein each test pattern image is indicative of process direction registration and cross-process registration of the first color separation in relation to the reference color separation;
wherein the color registration measurement logic determines a second registration measurement associated with the first color separation in relation to the reference color separation for each test pattern image, the first and second registration measurements providing process and cross-process measurements for the first color separation; and
wherein the repeatable registration error determining logic determines a second repeatable registration error pattern associated with the first color separation and the selected target media in relation to the cyclic characteristic based at least in part on the second registration measurements determined by the color registration measurement logic.
19. The apparatus set forth in claim 14, the marking engine further comprising:
a belt to transfer marking material from the color separation stations to the selected target media, wherein the cyclic characteristic is cyclic in relation to a revolution of the belt.
20. The apparatus set forth in claim 19 wherein the image receiving member includes the belt.
21. The apparatus set forth in claim 14, the marking engine further comprising:
a second color separation station; and
a third color separation station;
wherein the controller selectively marks the plurality of test pattern images on the image receiving member using the second and third color separation stations;
wherein the color registration measurement logic determines a second registration measurement associated with the second color separation in relation to the reference color separation for each test pattern image, the second registration measurements providing one of process measurements and cross-process measurements for the second color separation;
wherein the repeatable registration error determining logic determines a second repeatable registration error pattern associated with the second color separation and the selected target media in relation to the cyclic characteristic based at least in part on the second registration measurements determined by the color registration measurement logic;
wherein the color registration measurement logic determines a third registration measurement associated with the third color separation in relation to the reference color separation for each test pattern image, the third registration measurements providing one of process measurements and cross-process measurements for the third color separation; and
wherein the repeatable registration error determining logic determines a third repeatable registration error pattern associated with the third color separation and the selected target media in relation to the cyclic characteristic based at least in part on the third registration measurements determined by the color registration measurement logic.
22. The apparatus set forth in claim 14 wherein the multicolor marking platform is at least one of an electrophotographic marking system, a xerographic marking system, an ink marking system, an inkjet marking system, a printing press, an offset printing press, a printer, a copier, and a multifunction device.
23. A method of measuring color-to-color registration in a multicolor marking platform, comprising:
a) marking a plurality of test pattern images on an image receiving member to form a test pattern image array using a reference color separation station and a first color separation station over a process direction span and a cross-process direction span in relation to a selected target media and a cyclic characteristic of the multicolor marking platform;
b) detecting each test pattern image on the image receiving member;
c) determining a process registration measurement associated with the first color separation in relation to the reference color separation for each test pattern image;
d) determining a cross-process registration measurement associated with the first color separation in relation to the reference color separation for each test pattern image;
e) determining a repeatable process registration error pattern associated with the first color separation and the selected target media in relation to the cyclic characteristic based at least in part on the process registration measurements determined in c); and
f) determining a repeatable cross-process registration error pattern associated with the first color separation and the selected target media in relation to the cyclic characteristic based at least in part on the cross-process registration measurements determined in d).
24. The method set forth in claim 23, further comprising:
g) averaging process registration measurements for test pattern images positioned in cross-process direction relation during the determining in e); and
h) averaging first cross-process registration measurements for test pattern images positioned in cross-process direction relation during the determining in f).
25. The method set forth in claim 23 wherein the process direction span for the marking in a) continues for a plurality of cycles in relation to the cyclic characteristic, further comprising:
g) averaging process registration measurements for test pattern images positioned in cyclic relation with respect to absolute cross-process direction for the cyclic characteristic during the determining in e); and
h) averaging cross-process registration measurements for test pattern images positioned in cyclic relation with respect to absolute cross-process direction for the cyclic characteristic during the determining in f).