1. A method of forming an image, comprising:
providing an image forming medium comprising:
a substrate; and
an imaging layer coated on or impregnated into said substrate, wherein the imaging layer comprises a photochromic polymer, optionally dispersed in a polymeric binder, the photochromic polymer comprising a polymer having at least one photochromic unit grafted therein; and
heating the photochromic polymer to a temperature at or near a glass transition temperature or melting temperature of the photochromic polymer; and
exposing the image forming medium to UV irradiation of a first wavelength in an imagewise manner for a time period ranging from about 10 milliseconds to about 5 minutes at an intensity ranging from about 0.1 mWcm2 to about 100 mWcm2 to form a visible image,
wherein the polymer and the photochromic unit are selected so that:
the imaging layer exhibits a reversible transition between a colorless state and a colored state in response to heat and light, and
the imaging layer does not exhibit a transition from the colored state to colorless state when heated in the absence of light.
2. The method of claim 1, further comprising:
exposing the image forming medium bearing said image to light irradiation of a second wavelength in an imagewise manner, optionally while heating the photochromic polymer to a temperature at or near a glass transition temperature or melting temperature of the photochromic polymer, wherein said light irradiation causes said photochromic polymer to change from the colored state to the colorless state; and
repeating the step of exposing the image forming medium to the UV irradiation of a first wavelength in an imagewise manner at least one additional time.
3. The method of claim 1, where the heating heats the photochromic polymer to a temperature within about 10\xb0 C. of the glass transition temperature or melting temperature of the photochromic polymer.
4. An image forming medium, comprising:
a substrate; and
an imaging layer coated on or impregnated into said substrate, the imaging layer comprising a photochromic polymer, optionally dispersed in a polymeric binder, the photochromic polymer comprising a polymer having at least one photochromic unit grafted therein;
wherein the polymer and the photochromic unit are selected so that:
the imaging layer exhibits a reversible transition between a colorless state and a colored state in response to heat and light;
the imaging layer does not exhibit a transition from the colored state to the colorless state when heated in the absence of light; and
the photochromic polymer converts from a colorless state to a colored state upon irradiation with light of a first wavelength and converts from a colored state to a colorless state upon irradiation with light of a second wavelength different from the first wavelength.
5. The image forming medium of claim 4, wherein the photochromic polymer converts from the colorless state to the colored state upon irradiation with light of the first wavelength only when the photochromic polymer is heated to a temperature at or near a glass transition or melting temperature of the photochromic polymer.
6. The image forming medium of claim 4, wherein the photochromic unit is selected from the group consisting of a spiropyran compound, spirooxazine, thiospiropyran, a benzo compound, naphthopyran, stilbene, azobenzene, bisimidazol, spirodihydroindolizine, quinine, perimidinespirocyclohexadienone, viologen, fulgide, fulgimide, diarylethene, hydrazine, anil, aryl disulfide, and aryl thiosulfonate.
7. The image forming medium of claim 4, wherein the photochromic unit is selected from the group consisting of fulgides and diarylethenes.
8. The image forming medium of claim 4, wherein the photochromic unit is grafted into a main chain of said photochromic polymer.
9. The image forming medium of claim 4, wherein the photochromic unit is grafted into a side chain of said photochromic polymer.
10. The image forming medium of claim 4, wherein the photochromic polymer comprises multiple photochromic units grafted therein.
11. The image forming medium of claim 4, wherein the photochromic polymer is thermally stable.
12. The image forming medium of claim 4, wherein the polymer is selected from the group consisting of polyalkylacrylates, polycarbonates, polyethylenes, oxidized polyethylene, polypropylene, polyisobutylene, polystyrenes, poly(styrene)-co-(ethylene), polysulfones, polyethersulfones, polyarylsulfones, polyarylethers, polyolefins, polyacrylates, polyvinyl derivatives, cellulose derivatives, polyurethanes, polyamides, polyimides, polyesters, silicone resins, epoxy resins, polyvinyl alcohol, polyacrylic acid, polystyrene-acrylonitrile, polyethylene-acrylate, vinylidenechioride-vinyichioride, vinylacetate-vinylidene chloride, styrene-alkyd resins, and mixtures thereof.
13. The image forming medium of claim 4, wherein the imaging layer further comprises said polymeric binder.
14. The image forming medium of claim 4, wherein the imaging layer further comprises a phase change binder.
15. The image forming medium of claim 13, wherein said polymer binder is the same as the polymer forming the photochromic polymer but without the photochromic unit.
16. The image forming medium of claim 4, wherein the photochromic polymer is present in an amount of from about 0.01% to about 20% by weight of a total dry weight of the imaging layer.
17. The image forming medium of claim 4, wherein the substrate is selected from the group consisting of glass, ceramic, wood, plastic, paper, fabric, textile, metals, plain paper, and coated paper.
18. The image forming medium of claim 4, wherein the photochromic polymer is a diarylethene polymer of formula (I):
wherein n is greater than 1.
19. A method of making an image forming medium, comprising applying an imaging layer composition to a substrate, wherein the imaging layer composition comprises a photochromic polymer, optionally dispersed in a polymeric binder, the photochromic polymer comprising a polymer having at least one photochromic unit grafted therein;
wherein the polymer and the photochromic unit are selected so that:
the imaging layer exhibits a reversible transition between a colorless state and a colored state in response to heat and light, and
the imaging layer does not exhibit a transition from the colored state to the colorless state when heated in the absence of light.
20. The method of claim 19, wherein the applying comprises coating the imaging layer over the substrate or impregnating the imaging layer into the substrate.
21. The method of claim 19, wherein the imaging layer composition further comprises the polymeric binder.
22. The method of claim 19, wherein the imaging layer composition further comprises the phase change binder.
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 computer-implemented method for calibrating the timing for a mark-on-belt (MOB) sensor, comprising:
marking a photoreceptor belt with cyan portions of at least a first and second calibration chevron ensembles;
using nominal timing, reading the first and second calibration chevron ensembles during a predefined sensor read window;
analyzing a first signal from an outboard MOB leg of an outboard MOB that measures and outboard side of the first calibration chevron ensemble, and analyzing a second signal from an outboard MOB leg of an inboard MOB that measures an outboard side of the second calibration chevron ensemble; and
for each chevron ensemble read, determining whether there are N cyan portions, where N is an integer, seen during the read window.
2. The method according to claim 1, wherein N cyan portions are detected in each read window, and further comprising:
computing an average for the time from a start of the read window to the first detected cyan portion for each of M captures, where M is an integer.
calculating a difference between the computed average and an expected distance value for the nominal start of the read window to the first chevron ensemble; and
adjusting a MOB read window offset value as a function of the calculated difference thereby centering the read window on the chevron ensembles.
3. The method according to claim 1, wherein fewer than N cyan portions are detected in each read window, and further comprising:
determining a starting position of the read window as a function of the number of cyan portions detected and their position in the chevron ensemble;
adjusting a MOB read window offset value as a function of the determined starting position of the read window thereby centering the read window on the chevron ensembles.
4. The method according to claim 3, wherein determining a starting position of the read window further comprises:
measuring time between detected cyan portions and comparing the measured time to and expected time between cyan portions in order to determine that one of a last portion and a first portion of the chevron ensemble has been captured;
determining an adjustment to the start time of the read window as a function of the captured portion of the chevron ensemble.
5. The method according to claim 1, wherein the cyan portions of the at least a first and second calibration chevron ensembles are printed having positions on the photoreceptor belt that correspond to their respective positions relative to the yellow, magenta, and key portions that are omitted from the chevron ensembles.
6. The method according to claim 1, wherein the calibration chevron ensembles are printed in one or more interdocument zones (IDZs) on the photoreceptor belt.
7. The method according to claim 1, wherein the N cyan portions correspond to a predetermined number of cyan marks in the OB side of the chevron ensemble pattern.
8. The method according to claim 1, further comprising printing the cyan portions in 10 pitch mode.
9. A processor configured to execute computer-executable instructions for performing the method of claim 1, the instructions being stored on a non-transitory computer-readable medium.
10. A system that facilitates calibrating mark-on-belt (MOB) sensor timing, comprising:
a printer comprising a photoreceptor belt, wherein the printer marks the photoreceptor belt with cyan portions of at least a first and second calibration chevron ensembles; and
a processor configured to:
using nominal timing, read the first and second calibration chevron ensembles during a predefined sensor read window;
analyze a first signal from an outboard MOB leg of an outboard MOB that measures and outboard side of the first calibration chevron ensemble, and analyze a second signal from an outboard MOB leg of an inboard MOB that measures an outboard side of the second calibration chevron ensemble; and
for each chevron ensemble read, determine whether there are N cyan portions, where N is an integer, seen during the read window.
11. The system according to claim 10, wherein N cyan portions are detected in each read window, and wherein the processor is further configured to:
compute an average for the time from a start of the read window to a first detected cyan portion for each of M captures, where M is an integer.
calculate a difference between the computed average and an expected distance value for the nominal start of the read window to the first chevron ensemble; and
adjust a MOB read window offset value as a function of the calculated difference thereby centering the read window on the chevron ensembles.
12. The system according to claim 10, wherein fewer than N cyan portions are detected in each read window, and wherein the processor is further configured to:
determine a starting position of the read window as a function of the number of cyan portions detected and their position in the chevron ensemble; and
adjust a MOB read window offset value as a function of the determined starting position of the read window thereby centering the read window on the chevron ensembles.
13. The system according to claim 12, wherein the processor, when determining a starting position of the read window, is further configured to:
measure time between detected cyan portions and comparing the measured time to an expected time between cyan portions in order to determine that one of a last portion and a first portion of the chevron ensemble has been captured;
determine an adjustment to the start time of the read window as a function of the captured portion of the chevron ensemble.
14. The system according to claim 10, wherein the cyan portions of the first and second calibration chevron ensembles are printed in positions on the photoreceptor belt that correspond to their respective positions relative to the yellow, magenta, and key portions that are omitted from the chevron ensembles.
15. The system according to claim 10, wherein the calibration chevron ensembles are printed in one or more interdocument zones (IDZs) on the photoreceptor belt.
16. The system according to claim 10, wherein the N cyan portions correspond to a predetermined number of cyan marks in the OB side of the chevron ensemble pattern.
17. The system according to claim 10, wherein the printer prints the cyan portions in 10 pitch mode.
18. A computer-implemented method for calibrating MOB sensor timing, comprising:
marking inter-document zones of a photoreceptor belt with fewer than all lines of at least a first and second calibration chevron ensembles, wherein the marked lines have a common color;
reading the first and second calibration chevron ensembles during a predefined sensor read window;
analyzing a first signal from an outboard MOB leg of an outboard MOB that measures and outboard side of the first calibration chevron ensemble, and analyzing a second signal from an outboard MOB leg of an inboard MOB that measures an outboard side of the second calibration chevron ensemble; and
for each inter-document zone, determining whether N lines are detected, where N is an integer, seen during the read window.
19. The method according to claim 18, wherein N lines are detected in each read window, and further comprising:
computing an average for the time from a start of the read window to a first detected line for each of M captures, where M is an integer.
calculating a difference between the computed average and an expected distance value for a nominal start of the read window to the first chevron ensemble; and
adjusting a MOB read window offset value as a function of the calculated difference thereby centering the read window on the chevron ensembles.
20. The method according to claim 18, wherein fewer than N lines are detected in each read window, and further comprising:
determining a starting position of the read window as a function of the number of lines detected and their position in the chevron ensemble;
adjusting a MOB read window offset value as a function of the determined starting position of the read window thereby centering the read window on the chevron ensembles.
21. The method according to claim 20, wherein determining a starting position of the read window further comprises:
measuring time between detected lines and comparing the measured time to and expected time between lines in order to determine that one of a last portion and a first portion of the chevron ensemble has been captured;
determining an adjustment to the start time of the read window as a function of the captured portion of the chevron ensemble.
22. The method according to claim 18, wherein the common color is cyan.