1. A laser-markable plastic composition comprising a polymer component and a dopant, wherein said dopant comprises graphite particles have one or more coatings.
2. A laser-markable plastic composition according to claim 1, wherein said graphite particles are coated with CaCO3, CaSO4, Turnbull’s blue, carbon black, TiO2, (Sn,Sb)O2 (tin dioxide doped with antimony), or combinations thereof.
3. A laser-markable plastic composition according to claim 2, where said graphite particles have one, two, three or four layers of coatings.
4. A laser-markable plastic composition according to claim 1, wherein said graphite particles have two or more coatings and have an intermediate layer of TiO2, (Sn,Sb)O2, or combinations thereof.
5. A laser-markable plastic composition according to claim 1, wherein said dopant comprises graphite lamellae coated with CaCO3, CaSO4, Tumbull’s blue, carbon black, TiO2, (Sn,Sb)O2 or combinations thereof.
6. A laser-markable plastic composition according to claim 1, wherein the amount of dopant is 0.01-4% by weight, based on the total weight of the polymer component.
7. A laser-markable plastic composition according to claim 1, wherein the polymer component is polyethylene, polypropylene, polyamide, polyester, polyester ester, polyether ester, polyphenylene ether, polyacetal, polybutylene, terephthalate, polymethyl methacrylate, polyvinyl acetal, polystyrene, acrylonitrile-butadiene-styrene (ABS), acrylonitrile-styrene-acrylate (ASA), polycarbonate, polyether sulfone, polyether ketone, a copolymer thereof, or a mixture thereof.
8. A laser-markable plastic composition according to claim 7, wherein said graphite particles are coated with CaCO3, CaSO4, Turnbull’s blue, carbon black, TiO2, (Sn,Sb)O2, or combinations thereof.
9. A laser-markable plastic composition according to claim 8, wherein the amount of dopant is 0.01-4% by weight, based on the total weight of the polymer component.
10. A laser-markable plastic composition according to claim 1, wherein said composition also comprises color pigments, white pigments, black pigments, effect pigments, dyes, or combinations thereof.
11. A process for producing a laser-markable plastic composition comprising mixing at least one thermoplastic polymer or copolymer with graphite particles, wherein said graphite particles have one or more coatings, and then shaping the resultant mixture with exposure to heat.
12. In a process of marking a laser-markable plastic material comprising exposing the material to a laser, the improvement wherein said material is made from a composition according to claim 1.
13. A laser-markable plastic moulding prepared by the process according to claim 11.
14. A laser-markable plastic composition according to claim 6, wherein the amount of dopant is 0.3-2.5% by weight, based on the total weight of the polymer component.
15. A laser-markable plastic composition according to claim 1, wherein said graphite particles are graphite lamellae having an average particle size of 0.1-200 m, irregularly-shaped graphite particles having an average diameter of 0.1-200 m, or a mixture thereof.
16. A laser-markable plastic composition according to claim 1, wherein said graphite particles are graphite lamellae having an average particle size of 0.5-20 m, irregularly-shaped graphite particles having an average diameter of 0.1-50 m, or a mixture thereof.
17. A laser-markable composition according to claim 1, wherein said graphite particles are: (a) graphite having a TiO2 coating and a CaCO3 coating, (b) graphite having a TiO2 coating and a CaSO4 coating, (c) graphite having a TiO2 coating and a Tumbull’s blue coating, (d) graphite having a TiO2 coating, a SiO2 coating and a coating of (Sn,Sb)O2 or combinations thereof, (e) graphite having a SnO2 coating, a carbon black coating, and a TiO2 coating, or (f) graphite having a Tumbull’s blue coating.
18. A process according to claim 12, wherein the laser used to mark the plastic material has a wavelength of 157 nm to 10.6 m.
19. A process according to claim 12, wherein the laser used to mark the plastic material is an Nd:YAG laser, a CO2 laser, or a pulsed-UV laser.
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 developing apparatus for developing an electrostatic latent image formed on an electrophotographic photosensitive drum by use of a developing agent, comprising:
a developing agent carrier configured and positioned to supply the developing agent to the photosensitive drum to develop the electrostatic latent image formed on the photosensitive drum;
a layer thickness limiting member configured and positioned to limit a layer thickness of the developing agent carried on a surface of said developing agent carrier, said layer thickness limiting member being disposed to form a gap with said developing agent carrier;
a sealing member configured and positioned to restrict the developing agent from leaking out of an end in a longitudinal direction of said developing agent carrier; and
an elastic member arranged to be in contact with said developing agent carrier to prevent the gap between said developing agent carrier and said layer thickness limiting member from changing upon bending of said developing agent carrier, wherein said elastic member is in contact with said developing agent carrier at an outer position in the longitudinal direction with respect to a position at which said sealing member is disposed.
2. The developing apparatus according to claim 1, wherein said elastic member is structured to comprise a plurality of layers.
3. The developing apparatus according to claim 2, wherein the plurality of layers is structured to comprise a surface layer made of a felt and a second layer made of an elastic body.
4. The developing apparatus according to claim 1, 2, or 3, wherein said elastic member is in contact with said developing agent carrier between a bearing at which said developing agent carrier is supported and said sealing member in the longitudinal direction.
5. The developing apparatus according to claim 1, wherein said sealing member is structured to comprise a surface layer made of a felt and a second layer made of an elastic body.
6. A process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, comprising:
an electrophotographic photosensitive drum;
a developing agent carrier configured and positioned to supply a developing agent to said photosensitive drum to develop an electrostatic latent image formed on said photosensitive drum by use of the developing agent;
a layer thickness limiting member configured and positioned to limit a layer thickness of the developing agent carried on a surface of said developing agent carrier, said layer thickness limiting member being disposed to form a gap with said developing agent carrier;
a sealing member configured and positioned to restrict the developing agent from leaking out of an end in a longitudinal direction of said developing agent carrier; and
an elastic member arranged to be in contact with said developing agent carrier to prevent the gap between said developing agent carrier and said layer thickness limiting member from changing upon bending of said developing agent carrier, wherein said elastic member is in contact with said developing agent carrier at an outer position in the longitudinal direction with respect to a position at which said sealing member is disposed.
7. The process cartridge according to claim 6 wherein said elastic member is structured to comprise a plurality of layers.
8. The process cartridge according to claim 7, wherein the plurality of layers is structured to comprise a surface layer made of a felt and a second layer made of an elastic body.
9. The process cartridge according to claim 6, 7, or 8, wherein said elastic member is in contact with said developing agent carrier between a bearing at which said developing agent carrier is supported and said sealing member in the longitudinal direction.
10. The process cartridge according to claim 6, wherein said sealing member is structured to comprise a surface layer made of a felt and a second layer made of an elastic body.
11. An electrophotographic image forming apparatus for forming an image on a recording medium, comprising:
(i) mounting means for detachably mounting a process cartridge including:
an electrophotographic photosensitive drum;
a developing agent carrier configured and positioned to supply a developing agent to the photosensitive drum to develop an electrostatic latent image formed on the photosensitive drum by use of the developing agent;
a layer thickness limiting member configured and positioned to limit a layer thickness of the developing agent carried on a surface of the developing agent carrier, the layer thickness limiting member being disposed to form a gap with the developing agent carrier;
a sealing member configured and positioned to restrict the developing agent from leaking out of an end in a longitudinal direction of the developing agent carrier; and
an elastic member arranged to be in contact with the developing agent carrier to prevent the gap between the developing agent carrier and the layer thickness limiting member from changing, wherein the elastic member is in contact with the developing agent carrier at an outer position in the longitudinal direction with respect to a position at which the sealing member is disposed; and
(ii) feeding means for feeding the recording medium.
12. An electrophotographic image forming apparatus for forming an image on a recording medium, comprising:
an electrophotographic photosensitive drum;
a developing agent carrier configured and positioned to supply a developing agent to said photosensitive drum to develop an electrostatic latent image formed on said photosensitive drum by use of the developing agent;
a layer thickness limiting member configured and positioned to limit a layer thickness of the developing agent carried on a surface of said developing agent carrier, said layer thickness limiting member being disposed to form a gap with said developing agent carrier;
a sealing member configured and positioned to restrict the developing agent from leaking out of an end in a longitudinal direction of said developing agent carrier;
an elastic member arranged to be in contact with said developing agent carrier to prevent the gap between said developing agent carrier and said layer thickness limiting member from changing, wherein said elastic member contacts said developing agent carrier at an outer position in the longitudinal direction with respect to a position at which said sealing member is disposed; and
feeding means for feeding the recording medium.