Method and apparatus for imaging using an intermediate transfer member

• US 5,636,349 A
• Filed: 09/03/1993
• Issued: 06/03/1997
• Est. Priority Date: 09/08/1988
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Indigo BV (HP Inc.)
• Original Assignee: Indigo NV (HP Inc.)
• Inventors: Landa, Benzion, Lior, Ishaiau, Pinhas, Hanna
• Primary Examiner(s): Pendegrass, Joan H.
• Application Number:
  US08/116,198
• Time in Patent Office: 1,369 Days
• Field of Search: 355/256, 355/271, 355/273, 355/277, 355/279, 355/286, 355/290, 219/216, 219/469, 219/470, 430/126
• US Class Current: 399/307
• CPC Class Codes: G03G 15/161 with means for handling the intermediate support, e.g. heating, cleaning, coating with a transfer agent
• CPC Class Codes: G03G 15/162 details of the the intermediate support, e.g. chemical composition
• CPC Class Codes: G03G 15/238 using more than one reusable electrographic recording member, e.g. single pass duplex copiers
• CPC Class Codes: G03G 2215/0174 plural rotations of recording member to produce multicoloured copy
• CPC Class Codes: G03G 2215/0626 liquid type (at developing position)
• CPC Class Codes: G03G 2215/1671 Preheating the copy medium before the transfer point
• CPC Class Codes: G03G 2215/1695 at the second or higher order transfer point
• CPC Class Codes: G03G 5/04 Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor

Abstract

An imaging apparatus including an image bearing surface having formed thereon a liquid image comprising carrier liquid and toner particles, an intermediate transfer member positioned in operative association with the image bearing surface, a first transfer station at which the liquid image is transferred from the image bearing surface onto the intermediate transfer member, and a second transfer station at which the liquid image is transferred from the intermediate transfer member onto a substrate including a source of heat which heats the intermediate transfer member and the liquid image so as to cause the toner to adhere to the substrate and whereat the intermediate transfer member and the liquid image are cooled sufficiently such that the adhesion of the toner to the intermediate transfer member is less than the cohesion of the toner.

Claims

1. Imaging apparatus comprising:

an image bearing surface having formed thereon a liquid image comprising carrier liquid and toner particles;

an intermediate transfer member positioned in operative association with the image bearing surface;

a first transfer station at which the liquid image is transferred from the image bearing surface onto the intermediate transfer member; and

a second transfer station at which the liquid image is transferred from the intermediate transfer member onto a substrate including source of heat which heats the intermediate transfer member and the liquid image so as to cause the toner to adhere to the substrate and wherein the intermediate transfer member and the liquid image are cooled sufficiently such that the adhesion of the toner to the intermediate transfer member is less than the cohesion of the toner.

2. Apparatus according to claim 1 wherein the source of heat is operative to heat the liquid image to a temperature below the melting point of the toner.

3. Apparatus according to claim 2 wherein the toner solvates the carrier liquid at a solvation temperature above room temperature and the source of heat is operative to heat the image above the solvation temperature.

4. Apparatus according to claim 3 wherein said image is cooled to a temperature below said solvation temperature at the second transfer station.

5. Apparatus according to claim 4 wherein the heat source is operative to heat the liquid image to a temperature above the solvation temperature before contact with the substrate and wherein the image is cooled during contact with the substrate to a temperature below the solvation temperature.

6. Apparatus according to claim 5 wherein the substrate comprises a heat sink which cools the image to a temperature below said solvation temperature.

7. Apparatus according to claim 4 wherein the substrate comprises a heat sink which cools the image to a temperature below said solvation temperature.

8. Apparatus according to claim 1 wherein said intermediate transfer member comprises end portions and a thin walled cylinder which is unbacked by a solid structural support between said end portions.

9. Apparatus according to claim 8, wherein said thin walled cylinder has a thickness of less than 125 microns.

10. Apparatus according to claim 8, wherein said thin walled cylinder comprises a pneumatically pressurized thin wall cylinder, and further comprising means for axially tensioning said thin walled cylinder.

11. Apparatus according to claim 1 wherein said intermediate transfer member comprises a relatively heat conductive inner layer and a relatively heat insulative outer layer.

12. Apparatus according to claim 1 and wherein said intermediate transfer member has a low effective heat capacity such that the surface temperature of the intermediate transfer member is substantially reduced during transfer of an image therefrom onto a substrate.

13. Apparatus according to claim 1 wherein said intermediate transfer member has formed thereon a release coating for said toner particles.

14. Apparatus according to claim 1 wherein transfer of the toner particles to the intermediate transfer member is by electrostatic transfer.

15. Apparatus according to claim 14 wherein said intermediate transfer member has formed thereon a release coating for said toner.

16. Apparatus according to claim 14 wherein said intermediate transfer member has formed thereon a release coating.

17. Apparatus according to claim 1 wherein the substrate comprises a heat sink which cools the intermediate transfer member and the liquid image sufficiently such that the adhesion of the toner to the intermediate transfer member is less than the cohesion of the toner.

18. Imaging apparatus comprising:

an image bearing surface;

an intermediate transfer member positioned in operative association with the image bearing surface;

a developer which provides multiple liquid images on said image bearing surface the images comprising carrier liquid and toner;

a first transfer station at which said multiple liquid images are transferred from the image bearing surface onto the intermediate transfer member; and

a second transfer station at which the multiple liquid images are transferred from the intermediate transfer member onto a substrate including a source of heat which heats the intermediate transfer member and the liquid image so as to cause the toner in the images to adhere to the substrate and wherein the intermediate transfer member and the liquid image are cooled sufficiently such that the adhesion of the toner to the intermediate transfer member is less than the cohesion of the toner.

19. Apparatus according to claim 18 wherein said intermediate transfer member has formed thereon a release coating for said toner.

20. Apparatus according to claim 18 wherein transfer of the toner to the intermediate transfer member is by electrostatic transfer.

21. Apparatus according to claim 20 wherein said intermediate transfer member has formed thereon a release coating for said toner particles.

22. Apparatus according to claim 20 wherein said intermediate transfer member has formed thereon a release coating.

23. Apparatus according to claim 18 wherein the substrate comprises a heat sink which cools the intermediate transfer member and the liquid image sufficiently such that the adhesion of the toner to the intermediate transfer member is less than the cohesion of the toner.

24. Imaging apparatus comprising:

an image bearing surface having a developed image formed thereon;

an intermediate transfer member positioned in operative association with the image bearing surface, wherein said intermediate transfer member comprised a thin walled cylinder having end portions and a cylindrical image transfer surface therebetween and wherein said thin walled cylinder is backed by a solid structural support at said end portions and which is unbacked by a solid structural support between said end portions and wherein said thin walled cylinder is a pneumatically pressurized thin walled cylinder;

a first transfer station at which the image is transferred from the image bearing surface onto the intermediate transfer member; and

a second transfer station at which the image is transferred from the intermediate transfer member onto a substrate.

25. Apparatus according to claim 24 wherein said thin walled cylinder has a thickness less than about 50 microns.

26. Apparatus according to claim 25 wherein said thin walled cylinder has a thickness less than about 30 microns.

27. Apparatus according to claim 26 wherein said thin walled cylinder has a thickness less than about 7 microns.

28. Apparatus according to claim 26 and also comprising means for passing electrical current through said thin walled cylinder for producing direct resistance heating thereof.

29. Apparatus according to claim 25 wherein said thin walled cylinder comprises a layer of polyester and a thin release layer.

30. Apparatus according to claim 25 wherein said thin walled cylinder comprises a layer of Kapton and a thin release layer.

31. Apparatus according to claim 25, wherein said thin walled cylinder comprises a metallic material.

32. Apparatus according to claim 31, wherein said thin walled cylinder comprises a layer of nickel alloy and a thin release layer.

33. Apparatus according to claim 24 and further comprising means for axially tensioning said thin walled cylinder.

34. Apparatus according to claim 33, wherein said thin walled cylinder has a thickness of less than 125 microns.

35. Apparatus according to claim 34, wherein said thin walled cylinder has a thickness of less than 50 microns.

36. Apparatus according to claim 24, wherein said thin walled cylinder has a thickness of less than 125 microns.

37. Imaging apparatus comprising:

an image bearing surface;

an intermediate transfer member positioned in operative association with the image bearing surface, wherein said intermediate transfer member comprises a thin walled cylinder having end portions and a cylindrical image transfer surface therebetween and wherein said thin walled cylinder is backed by a solid structural support at said end portions and which is unbacked by a solid structural support between said end portions and wherein said thin walled cylinder is a pneumatically pressurized thin walled cylinder;

a developer which provides said multiple images on said image bearing surface the images comprising carrier liquid and toner;

a first transfer station at which said multiple images are transferred from the image bearing surface onto the intermediate transfer member; and

a second transfer station at which the multiple images are transferred from the intermediate transfer member onto a substrate.

38. Apparatus according to claim 37, wherein said thin walled cylinder has a thickness of less than 125 microns.

39. Apparatus according to claim 37, further comprising means for axially tensioning said thin walled cylinder.

40. Imaging apparatus comprising:

an image bearing surface having a developed image formed thereon;

an intermediate transfer member positioned in operative association with the image bearing surface, wherein said intermediate transfer member comprises a thin walled cylinder having end portions and a cylindrical image transfer surface therebetween end wherein said thin walled cylinder is backed by a solid structural support at said end portions and which is unbacked by a solid structural support between said end portions and wherein said intermediate transfer member includes means for axially tensioning said thin wall cylinder;

a first transfer station at which the image is transferred from the image bearing surface onto the intermediate transfer member; and

a second transfer station at which the image is transferred from the intermediate transfer member onto a substrate.

41. Apparatus according to claim 40, wherein said thin walled cylinder has a thickness of less than 125 microns.

42. Apparatus according to claim 40, wherein said thin walled cylinder comprises a pneumatically pressurized thin wall cylinder.

43. An intermediate transfer member for transfer of an image from an image bearing surface onto a substrate and comprising a thin walled cylinder having end portions and a cylindrical image transfer surface therebetween and wherein said than walled cylinder has a thickness of less than 125 microns which is which is backed by a solid structural support at said end portions and which is unbacked by a solid structural support between said end portions.

44. An intermediate transfer member for transfer of an image from an image bearing surface onto a substrate and comprising a thin walled cylinder having end portions and a cylindrical image transfer surface therebetween and wherein said thin walled cylinder is backed by a solid structural support at said end portions and which is unbacked by a solid structural support between said end portions and wherein said intermediate transfer member also comprises means for axially tensioning said thin walled cylinder.

45. An intermediate transfer member according to claim 44 and wherein said thin walled cylinder has a thickness less than about 50 microns.

46. Apparatus according to claim 45 wherein said thin walled cylinder has a thickness less than about 30 microns.

47. An intermediate transfer member according to claim 46 wherein said thin walled cylinder has a thickness less than about 7 microns.

48. An intermediate transfer member according to claim 46, wherein said thin walled cylinder comprises a metallic material.

49. An intermediate transfer member according to claim 48, wherein said thin walled cylinder comprises a layer of nickel alloy and a thin release layer.

50. An intermediate transfer member according to claim 46 and also comprising means for passing electrical current through said thin walled cylinder for producing direct resistance heating thereof.

51. An intermediate transfer member according to claim 45 wherein said thin walled cylinder comprises a layer of polyester and a thin release layer.

52. An intermediate transfer member according to claim 45 wherein said thin walled cylinder comprises a layer of Kapton and a thin release layer.

53. Member according to claim 44, wherein said thin walled cylinder has a thickness of less than 125 microns.

54. An intermediate transfer member according to claim 44, wherein said thin walled cylinder comprises a pneumatically pressurized thin walled cylinder.

55. An intermediate transfer member according to claim 54, wherein said thin walled cylinder has a thickness of less than 125 microns.

56. An intermediate transfer member according to claim 55, wherein said thin walled cylinder has a thickness of less than 50 microns.

57. An intermediate transfer member for transfer of an image from an image bearing surface onto a substrate and comprising a thin walled cylinder having end portions and a cylindrical image transfer surface therebetween and wherein said thin walled cylinder is backed by a solid structural support at said end portions and which is unbacked by a solid structural support between said end portions and wherein said thin walled cylinder is a pneumatically pressurized thin walled cylinder.

58. An intermediate transfer member according to claim 57 and wherein said intermediate transfer member has a low effective heat capacity such that the surface temperature of the intermediate transfer member is substantially reduced during transfer of an image therefrom onto a substrate.

59. An intermediate transfer member according to claim 57 wherein said thin walled cylinder has a thickness of less than about 50 microns.

60. An intermediate transfer member according to claim 59 wherein said thin walled cylinder has a thickness of less than about 30 microns.

61. An intermediate transfer member according to claim 60 and also comprising means for passing electrical current through said thin walled cylinder for producing direct resistance heating thereof.

62. An intermediate transfer member according to claim 59 wherein said thin walled cylinder comprises a layer of polyester and a thin release layer.

63. An intermediate transfer member according to claim 59 wherein said thin walled cylinder comprises a layer of Kapton and a thin release layer.

64. An intermediate transfer member according to claim 59 wherein said thin walled cylinder has a thickness less than about 7 microns.

65. An intermediate transfer member according to claim 64 wherein said thin walled cylinder comprises a metallic material.

66. An intermediate transfer member according to claim 65, wherein said thin walled cylinder comprises a layer of nickel alloy and a thin release layer.

67. An intermediate transfer member according to claim 57, wherein said thin walled cylinder has a thickness of less than 125 microns.

68. A method for transfer of a liquid image from an image bearing surface onto a substrate comprising:

providing a liquid image on said image bearing surface, the liquid image comprising carrier liquid and toner;

positioning an intermediate transfer member in operative association with the image bearing surface;

first transferring said liquid image from the image bearing surface onto the intermediate transfer member; and

subsequently transferring the liquid image from the intermediate transfer member onto a substrate and including heating the intermediate transfer member and heating the liquid image so as to cause the toner to adhere to the substrate and cooling the intermediate transfer member sufficiently such that the adhesion of the toner thereto is less than the cohesion of the toner.

69. A method according to claim 68 wherein heating the liquid toner image includes heating the liquid toner image to a temperature below the melting point of the toner.

70. A method according to claim 69 wherein heating the liquid toner image includes heating said image to a temperature at which it solvates.

71. A method according to claim 70 wherein cooling the intermediate transfer member includes cooling said image to below said temperature at which it solvates.

72. A method according to claim 68 wherein said intermediate transfer member comprises a thin walled cylinder in which electrical current is passed through for producing direct resistance heating thereof.

73. A method according to claim 68 wherein said intermediate transfer member comprises a thin walled cylinder which is axially tensioned.

74. A method according to claim 68 wherein said intermediate transfer member comprises a thin walled cylinder which is pneumatically pressurized.

75. A method according to claim 68 wherein said intermediate transfer member has a low effective heat capacity such that the surface temperature of the intermediate transfer member is substantially reduced during transfer of an image therefrom onto a substrate.

76. A method according to claim 68 wherein said intermediate transfer member has formed thereon a release coating for said toner.

77. A method according to claim 68 wherein said intermediate transfer member has formed thereon a release coating.

78. An imaging method comprising:

sequentially providing multiple liquid images on an image bearing surface, the liquid images comprising carrier liquid and toner;

positioning an intermediate transfer member in operative association with the image bearing surface;

transferring the multiple liquid images from the image bearing surface onto the intermediate transfer member; and

transferring the multiple liquid images from the intermediate transfer member onto a substrate and including heating the intermediate transfer member and heating the liquid images so as to cause the toner in the images to adhere to the substrate and cooling the intermediate transfer member sufficiently such that the adhesion of the toner thereto is less than the cohesion of the toner.

79. A method according to claim 78 wherein said intermediate transfer member has formed thereon a release coating for said toner.

80. A method according to claim 78 wherein transfer of the toner to the intermediate transfer member is by electrostatic transfer.

81. An imaging apparatus for printing an image from a latent image formed on a latent image bearing surface comprising:

developing means for developing said latent image with a liquid developer, comprising carrier liquid and charged pigmented particles, to form a developed image;

an intermediate transfer member having formed thereon a release coating for the pigmented particles and which receives said developed image from said latent image bearing surface for subsequent transfer to a final substrate; and

a heat source which heats said developed image during its transfer from said latent image bearing surface to said intermediate transfer member.

82. Imaging apparatus according to claim 81 further comprising:

means for further heating said image prior to said subsequent transfer to said final substrate.

83. Imaging apparatus according to claim 81, and comprising:

a transfer station at which electrostatic transfer of the charged pigmented particles to the intermediate transfer member takes place.

84. A method for forming an image on a final substrate from a latent image on an image forming surface comprising:

developing said latent image using a liquid developer comprising carrier liquid and charged particles to form a liquid toner image at a first temperature; and

transferring said liquid toner image to an intermediate transfer member having thereon a release coating for said charged particles, said liquid toner image being at a higher temperature during said transfer step than said first temperature.

85. A method according to claim 84 comprising:

further transferring said liquid toner image from said intermediate transfer member to a final substrate, said liquid toner image being at a higher temperature during said further transferring step than during said transferring step.

86. A method according to claim 84 wherein said transfer is by electrophoresis.

87. Imaging apparatus comprising:

an image bearing surface having formed thereon a liquid image comprising carrier liquid and toner which solvates the carrier liquid at a solvation temperature above room temperature;

an intermediate transfer member positioned in operative association with the image bearing surface;

a first transfer station at which the liquid image is transferred from the image bearing surface onto the intermediate transfer member; and

a second transfer station at which the liquid image is transferred from the intermediate transfer member onto a substrate including a source of heat which heats the liquid toner image to a temperature above the solvation temperature, below the melting point of the toner and below the boiling point of the carrier liquid prior to the transfer of the image to the substrate.

88. Apparatus according to claim 87 wherein the intermediate transfer member and the heated liquid image are cooled sufficiently, at the second transfer station, such that the adhesion of the toner to the intermediate transfer member is less than the cohesion of the toner.

89. Apparatus according to claim 88 wherein the heated liquid toner image is cooled to a temperature below the solvation temperature at the second transfer station.

90. Apparatus according to claim 89 wherein the heat source is operative to heat the image such that it remains above the solvation temperature until contact of the image with the substrate.

91. Apparatus according to claim 89 wherein the substrate comprises a heat sink which cools the image to a temperature below said solvation temperature.

92. Apparatus according to claim 88 wherein the substrate comprises a heat sink which cools the intermediate transfer member and the liquid image sufficiently such that the adhesion of the toner to the intermediate transfer member is less than the cohesion of the toner.

93. A method for forming an image on a final substrate from at least one latent image formed on at least one image forming surface comprising:

developing a latent image using a liquid developer, comprising carrier liquid and charged toner particles, to form a first liquid toner image; and

transferring said liquid toner image to an intermediate transfer member coated with a release coating for the toner particles, said liquid toner image being at a higher temperature during said transfer than during said development.

94. A method according to claim 93 wherein the transfer to the intermediate transfer member is by electrostatic transfer.

95. An imaging apparatus for printing an image from a latent image formed on a latent image bearing surface comprising:

developing means for developing said latent image with a liquid developer, which comprises carrier liquid and charged pigmented particles, to form a developed image;

an intermediate transfer member having formed thereon a release coating which receives said developed image from said latent image bearing surface prior to subsequent transfer to a final substrate; and

a heat source which heats said developed image during its transfer from said latent image bearing surface to said intermediate transfer member.

96. Imaging apparatus according to claim 95, and comprising:

a transfer station at which electrostatic transfer of the charged pigmented particles to the intermediate transfer member takes place.

97. A method for forming an image on a final substrate from a latent image on an image forming surface comprising:

developing said latent image using a liquid developer, which comprises carrier liquid and charged particles, to form a liquid toner image at a first temperature; and

transferring said liquid toner image to an intermediate transfer member having thereon a release coating, said liquid toner image being at a higher temperature during said transfer than said first temperature.

98. A method according to claim 97 wherein said transfer is by electrophoresis.

99. A method for forming an image on a final substrate from at least one latent image formed on at least one image forming surface comprising:

developing a latent image using a liquid developer, comprising carrier liquid and charged toner particles, to form a liquid toner image; and

transferring said liquid toner image to an intermediate transfer member coated with a release coating for the toner particles, said liquid toner image being at a higher temperature during said transfer than during said development.

100. A method according to claim 99 wherein said transfer is by electrophoresis.

101. A method for forming an image on a final substrate from at least one latent image formed on at least one image forming surface comprising:

developing a latent image using a liquid developer, comprising carrier liquid and charged toner particles, to form a liquid toner image; and

electrostatically transferring said liquid toner image to an intermediate transfer member, said liquid toner image being at a higher temperature during said transfer than during said development.