Positively chargeable toner, image forming method and image forming apparatus

• US 6,235,441 B1
• Filed: 12/17/1999
• Issued: 05/22/2001
• Est. Priority Date: 12/17/1998
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Fujimoto, Masami, Fujikawa, Hiroyuki, Kobori, Takakuni, Tanikawa, Hirohide
• Primary Examiner(s): GOODROW, JOHN L
• Application Number:
  US09/465,836
• Time in Patent Office: 522 Days
• Field of Search: 430/106, 430/109, 430/110, 430/111, 399/222
• US Class Current: 430/108.21
• CPC Class Codes: G03G 9/08722 Polyvinylalcohols; Polyallylalcohols; Polyvinylethers; Polyvinylaldehydes; Polyvinylketones; Polyvinylketals
• CPC Class Codes: G03G 9/08726 Polymers of unsaturated acids or derivatives thereof
• CPC Class Codes: G03G 9/0874 Polymers comprising hetero rings in the side chains
• CPC Class Codes: G03G 9/08791 characterised by the presence of specified groups or side chains
• CPC Class Codes: G03G 9/08793 Crosslinked polymers
• CPC Class Codes: G03G 9/08795 characterised by their chemical properties, e.g. acidity, molecular weight, sensitivity to reactants
• CPC Class Codes: G03G 9/09758 comprising a heterocyclic ring

Abstract

A positively chargeable toner suitable to be carried on a cylindrical developer-carrying member having a resinous surface for developing an electrostatic latent image is formed from a composition including a binder resin, an imidazole compound and a colorant. The binder resin comprises at least one member selected from the group consisting of (i) a mixture of vinyl resin having a carboxyl group and a vinyl resin having a glycidyl group, (ii) a vinyl resin having both a carboxyl group and a glycidyl group, and (iii) a vinyl resin having a carboxyl group and a glycidyl group in a form reacted with each other. The imidazole compound is a compound having an imidazo unit represented by formula (1) below:

wherein R₁-R₄ independently denote hydrogen or a substituent as specified. In some cases, two or more such imidazole units can be included in a combined form to provide the imidazole compound. The imidazole compound is effective for promoting a crosslinking reaction between the carboxyl group and the glycidyl group to provide the toner with improved fixability and anti-offset property in combination.

Claims

1. A positively chargeable toner, comprising:

a binder resin, an imidazole compound and a colorant;

wherein

the binder resin comprises at least one member selected from the group consisting of (i) a mixture of vinyl resin having a carboxyl group and a vinyl resin having a glycidyl group, (ii) a vinyl resin having both a carboxyl group and a glycidyl group, and (iii) a vinyl resin having a carboxyl group and a glycidyl group in a form reacted with each other, and

the imidazole compound is a compound having an imidazole unit represented by formula (1) below;

wherein R₁, R₃ and R₄ independently denote hydrogen, an alkyl group capable of having a substituent, an aryl group capable of having a substituent, an aralkyl group capable of having a substituent, an amino group capable of having a substituent, a heterocyclic ring capable of having a substituent, or a halogen; and

R₂ denotes hydrogen, an alkyl group capable of having a substituent, an aryl group capable of having a substituent, an aralkyl group capable of having a substituent, or a heterocyclic group capable of having a substituent;

with the proviso that two or more imidazole units can be combined with each other via two of the groups R₁, R₂, R₃ and R₄ and an intervening bonding group selected from the group consisting of phenylene group, propenylene group, vinylene group, alkenylene group and alkylene group each capable of having a substituent; and

that R₃ and R₄ can be bonded to each other to form a saturated aliphatic ring, an unsaturated aliphatic ring, an aromatic ring or a heterocyclic ring.

2. The toner according to claim 1, wherein the toner contains a tetrahydrofuran (THF)-soluble content exhibiting a molecular weight distribution according to gel permeation chromatography (GPC) providing a number-average molecular weight (Mn) of 10³-4×

10⁴, and a weight-average molecular weight (Mw) of 10⁴-10⁷.

3. The toner according to claim 1, wherein the toner contains a tetrahydrofuran (THF)-soluble content providing a GPC (gel permeation chromatography) chromatogram exhibiting a main peak in a molecular weight region of 4×

10³-3×

10⁴.

4. The toner according to claim 3, wherein the GPC chromatogram exhibits a peak area in a molecular weight region of at most 3×

10⁴ which occupies 60-100% of an entire peak area on the GPC chromatogram.

5. The toner according to claim 1, wherein the toner contains a tetrahydrofuran (THF)-soluble content providing a GPC (gel permeation chromatography) chromatogram exhibiting at least one peak each in a molecular weight region of 4×

10³-3×

10⁴ and in a molecular weight region of 10⁵-10⁷.

6. The toner according to claim 1, wherein the toner contains a tetrahydrofuran (THF)-soluble content providing a GPC (gel permeation chromatography) chromatogram exhibiting at least one peak each in a molecular weight region of 4×

10³-3×

10⁴ and in a molecular weight region of 8×

10⁵-10⁷.

7. The toner according to claim 1, wherein the toner contains a tetrahydrofuran (THF)-soluble content providing a GPC (gel permeation chromatography) chromatogram exhibiting at least one peak each in a molecular weight region of 4×

10³-3×

10⁴, in a molecular weight region of 10⁵ to below 8×

10⁵, and in a molecular weight region of 8×

10⁵-10⁷.

8. The toner according to claim 7, wherein the GPC chromatogram exhibits a peak area in a molecular weight region of at least 10⁵ which occupies 5-40% of an entire peak area on the GPC chromatogram.

9. The toner according to claim 1, wherein the binder resin contains a THF-insoluble content of 0.1-60 wt. %.

10. The toner according to claim 1, wherein binder resin contains a THF-insoluble content of 5-60 wt. %.

11. The toner according to claim 1, wherein the binder resin contains a THF-insoluble content of 7-55 wt. %.

12. The toner according to claim 1, wherein binder resin contains a THF-insoluble content of 9-50 wt. %.

13. The toner according to claim 1, wherein the binder resin contains a THF-insoluble content of 10-45 wt. %.

14. The toner according to claim 1, wherein the toner contains a THF-soluble content having an acid value of 0.1-50 mgKOH/g.

15. The toner according to claim 1, wherein the toner contains a THF-soluble content having an acid value of 0.5-50 mgKOH/g.

16. The toner according to claim 1, wherein the toner contains a THF-soluble content having an acid value of 0.5-40 mgKOH/g.

17. The toner according to claim 1, wherein the toner contains a THF-soluble content having an acid value of 0.5-30 mgKOH/g.

18. The toner according to claim 1, wherein the toner contains a THF-soluble content having an acid value of 0.5-25 mgKOH/g.

19. The toner according to claim 1, wherein the toner contains a THF-soluble content having an acid value of 0.5-20 mgKOH/g.

20. The toner according to claim 1, wherein the toner has a storage modulus at 80°

C. (G′

(80°

C.)) of 1.0×

10⁵-2.0×

10⁶ Pa, and a storage modulus at 140°

C. (G′

(140°

C.)) of 1.0×

10³-2.0×

10⁴ Pa.

21. The toner according to claim 1, wherein the toner has a temperature giving a loss tangent (tan δ

) (=loss modulus/storage modulus) of 1 in a region of 90-130°

C., a loss tangent at 80°

C. (tan δ

(80°

C.)) of larger than 1, and a loss tangent at 140°

C. (tan δ

(140°

C.)) of smaller than 1.

22. The toner according to claim 1, wherein the toner has a storage modulus at 80°

C. (G′

(80°

C.)) of 1.0×

10⁵-2.0×

10⁶ Pa, a storage modulus at 140°

C. (G′

(140°

C.)) of 1.0×

10³-2.0×

10⁴ Pa, a temperature giving a loss tangent (tan δ

) (=loss modulus/storage modulus) of 1 in a region of 90-130°

C., a loss tangent at 80°

C. (tan δ

(80°

C.)) of larger than 1, and a loss tangent at 140°

C. (tan δ

(140°

C.)) of smaller than 1.

23. The toner according to claim 1, wherein the toner has been obtained through a step of melt-kneading at least the binder resin, the imidazole compound and the colorant under heating, and the toner has a storage modulus at 80°

C. (G′

(80°

C.)) of 1.0×

10⁵-2.0×

10⁶ Pa, and a storage modulus at 140°

C. (G′

(140°

C.)) of 1.0×

10³-2.0×

10⁴ Pa.

24. The toner according to claim 1, wherein the toner has been obtained through a step of melt-kneading at least the binder resin, the imidazole compound and the colorant under heating, and the toner has a temperature giving a loss tangent (tan δ

) (=loss modulus/storage modulus) of 1 in a region of 90-130°

C., a loss tangent at 80°

C. (tan δ

(80°

C.)) of larger than 1, and a loss tangent at 140°

C. (tan δ

(140°

C.)) of smaller than 1.

25. The toner according to claim 1, wherein the toner has been obtained through a step of melt-kneading at least the binder resin, the imidazole compound and the colorant under heating, and the toner has a storage modulus at 80°

C. (G′

(80°

C.)) of 1.0×

10⁵-2.0×

10⁶ Pa, a storage modulus at 140°

C. (G′

(140°

C.)) of 1.0×

10³-2.0×

10⁴ Pa, a temperature giving a loss tangent (tan δ

) (=loss modulus/storage modulus) of 1 in a region of 90-130°

C., a loss tangent at 80°

C. (tan δ

(80°

C.)) of larger than 1, and a loss tangent at 140°

C. (tan δ

(140°

C.)) of smaller than 1.

26. An image forming method, comprising the steps of:

forming an electrostatic latent image on an image-bearing member, and

developing the electrostatic latent image with a monocomponent developer comprising a positively chargeable toner carried on and conveyed by a developer-carrying member;

wherein the positively chargeable toner comprises a binder resin, an imidazole compound and a colorant;

wherein

the binder resin comprises at least one member selected from the group consisting of (i) a mixture of vinyl resin having a carboxyl group and a vinyl resin having a glycidyl group, (ii) a vinyl resin having both a carboxyl group and a glycidyl group, and (iii) a vinyl resin having a carboxyl group and a glycidyl group in a form reacted with each other, and

the imidazole compound is a compound having an imidazole unit represented by formula (1) below;

 

wherein R₁, R₃ and R₄ independently denote hydrogen, an alkyl. group capable of having a substituent, an aryl group capable of having a substituent, an aralkyl group capable of having a substituent, an amino group capable of having a substituent, a heterocyclic ring capable of having a substitutent, or a halogen and R₂ denotes hydrogen, an alkyl group capable of having a substituent, an aryl group capable of having a substituent, an aralkyl group capable of having a substituent, or a heterocyclic group capable of having a substituent with the proviso that two or more imidazole units can be combined with each other via two of the groups R₁, R₂, R₃ and R₄ and an intervening bonding group selected from the group consisting of phenylene group, propenylene group, vinylene group, alkenylene group and alkylene group each capable of having a substituent; and

that R₃ and R₄ can be bonded to each other to form a saturated aliphatic ring, an unsaturated aliphatic ring, an aromatic ring or a heterocyclic ring.

27. The image forming method according to claim 26, wherein the toner contains a tetrahydrofuran (THP)-soluble content exhibiting a molecular weight distribution according to gel permeation chromatography (GPC) providing a number-average molecular weight (Mn) of 10³-4×

10⁴, and a weight-average molecular weight (Mw) of 10⁴-10⁷.

28. The image forming method according to claim 26, wherein the toner contains a tetrahydrofuran (THF)-soluble content providing a GPC (gel permeation chromatography) chromatogram exhibiting a main peak in a molecular weight region of 4×

10³-3×

10⁴.

29. The image forming method according to claim 28, wherein the GPC chromatogram exhibits a peak area in a molecular weight region of at most 3×

10⁴ which occupies 60-100% of an entire peak area on the GPC chromatogram.

30. The image forming method according to claim 26, wherein the toner contains a tetrahydrofuran (THF)-soluble content providing a GPC (gel permeation chromatography) chromatogram exhibiting at least one peak each in a molecular weight region of 4×

10³-3×

10⁴ and in a molecular weight region of 10⁵-10⁷.

31. The image forming method according to claim 26, wherein the toner contains a tetrahydrofuran (THF)-soluble content providing a GPC (gel permeation chromatography) chromatogram exhibiting at least one peak each in a molecular weight region of 4×

10³-3×

10⁴ and in a molecular weight region of 8×

10⁵-10⁷.

32. The image forming method according to claim 26, wherein the toner contains a tetrahydrofuran (THF)-soluble content providing a GPC (gel permeation chromatography) chromatogram exhibiting at least one peak each in a molecular weight region of 4×

10³-3×

10⁴, in a molecular weight region of 10⁵ to below 8×

10⁵, and in a molecular weight region of 8×

10⁵-10⁷.

33. The image forming method according to claim 32, wherein the GPC chromatogram exhibits a peak area in a molecular weight region of at least 10⁵ which occupies 5-40% of an entire peak area on the GPC chromatogram.

34. The image forming method according to claim 26, wherein the binder resin contains a THF-insoluble content of 0.1-60 wt. %.

35. The image forming method according to claim 26, wherein binder resin contains a THF-insoluble content of 5-60 wt. %.

36. The image forming method according to claim 26, wherein the binder resin contains a THF-insoluble content of 7-55 wt. %.

37. The image forming method according to claim 26, wherein binder resin contains a THF-insoluble content of 9-50 wt. %.

38. The image forming method according to claim 26, wherein the binder resin contains a THF-insoluble content of 10-45 wt. %.

39. The image forming method according to claim 26, wherein the binder resin has an acid value of 0.1-50 mgKOH/g.

40. The image forming method according to claim 26, wherein the toner contains a THF-soluble content having an acid value of 0.5-50 mgKOH/g.

41. The image forming method according to claim 26, wherein the toner contains a THF-soluble content having an acid value of 0.5-40 mgKOH/g.

42. The image forming method according to claim 26, wherein the toner contains a THF-soluble content having an acid value of 0.5-30 mgKOH/g.

43. The image forming method according to claim 26, wherein the toner contains a THF-soluble content having as an acid value of 0.5-25 mgKOH/g.

44. The image forming method according to claim 26, wherein the toner contains a THF-soluble content having has an acid value of 0.5-20 mgKOH/g.

45. The image forming method according to claim 26, wherein the toner has a storage modulus at 80°

C. (G′

(80°

C.)) of 1.0×

10⁵-2.0×

10⁶ Pa, and a storage modulus at 140°

C. (G′

(140°

C.)) of 1.0×

10³-2.0×

10⁴ Pa.

46. The image forming method according to claim 26, wherein the toner has a temperature giving a loss tangent (tan δ

) (=loss modulus/storage modulus) of 1 in a region of 90-130°

C., a loss tangent at 80°

C. (tan δ

(80°

C.)) of larger than 1, and a loss tangent at 140°

C. (tan δ

(140°

C.)) of smaller than 1.

47. The image forming method according to claim 26, wherein the toner has a storage modulus at 80°

C. (G′

(80°

C.)) of 1.0×

10⁵-2.0×

10⁶ Pa, a storage modulus at 140°

C. (G′

(140°

C.)) of 2.0×

10³-1.0×

10⁴ Pa, a temperature giving a loss tangent (tan δ

) (=loss modulus/storage modulus) of 1 in a region of 90-130°

C., a loss tangent at 80°

C. (tan δ

(80°

C.)) of larger than 1, and a loss tangent at 140°

C. (tan δ

(140°

C.)) of smaller than 1.

48. The image forming method according to claim 26, wherein the toner has been obtained through a step of melt-kneading at least the binder resin, the imidazole compound and the colorant under heating, and the toner has a storage modulus at 80°

C. (G′

(80°

C.)) of 1.0×

10⁵-2.0×

10⁶ Pa, and a storage modulus at 140°

C. (G′

(140°

C.)) of 1.0×

10³-2.0×

10⁴ Pa.

49. The image forming method according to claim 26, wherein the toner has been obtained through a step of melt-kneading at least the binder resin, the imidazole compound and the colorant under heating, and the toner has a temperature giving a loss tangent (tan δ

) (=loss modulus/storage modulus) of 1 in a region of 90-130°

C., a loss tangent at 80°

C. (tan δ

(80°

C.)) of larger than 1, and a loss tangent at 140°

C. (tan δ

(140°

C.)) of smaller than 1.

50. The image forming method according to claim 26, wherein the toner has been obtained through a step of melt-kneading at least the binder resin, the imidazole compound and the colorant under heating, and the toner has a storage modulus at 80°

C. (G′

(80°

C.)) of 1.0×

10⁵-2.0×

10⁶ Pa, a storage modulus at 140°

C. (G′

(140°

C.)) of 1.0×

10³-2.0×

10⁴ Pa, a temperature giving a loss tangent (tan δ

) (=loss modulus/storage modulus) of 1 in a region of 90-130°

C., a loss tangent at 80°

C. (tan δ

(80°

C.)) of larger than 1, and a lose tangent at 140°

C. (tan δ

(140°

C.)) of smaller than 1.

51. The image forming method according to claim 26, wherein the developer-carrying member is in the form of a cylindrical sleeve formed of a material comprising a resin.

52. The image forming method according to claim 26, wherein the developer-carrying member comprises a substrate and a resin-containing coating layer formed on the substrate.

53. The image forming method according to claim 52, wherein the coating layer comprises at least one member selected from the group consisting of an electroconductive substrate, a filler and a solid lubricant, in addition to the resin.

54. The image forming method according to claim 26, wherein the image-bearing member comprises an electrophotographic photosensitive member.

55. The image forming method according to claim 26, wherein the electrostatic latent image is developed with the developer while a developing bias voltage comprising an alternating voltage is applied to the developer-carrying member.

56. The image forming method according to claim 55, wherein the developing bias voltage comprises an AC voltage superposed with a DC voltage.

57. An image forming apparatus, comprising:

an image-bearing member,

a latent image forming means for forming an electrostatic latent image on the image-bearing member, and

a developing means comprising a developer-carrying member for carrying and conveying thereon a mono-component developer comprising a positively chargeable toner which comprises a binder resin, an imidazole compound and a colorant;

wherein

the binder resin comprises at least one member selected from the group consisting of (i) a mixture of vinyl resin having a carboxyl group and a vinyl resin having a glycidyl group, (ii) a vinyl resin having both a carboxyl group and a glycidyl group, and (iii) a vinyl resin having a carboxyl group and a glycidyl group in a form reacted with each other, and

the imidazole compound is a compound having an imidazole unit represented by formula (1) below;

 

wherein R₁, R₃ and R₄ independently denote hydrogen, an alkyl group capable of having a substituent, an aryl group capable of having a substituent, an aralkyl group capable of having a substituent, an amino group capable of having a substituent;

a heterocyclic ring capable of having a substituent, or a halogen; and

R₂ denotes hydrogen, an alkyl group capable of having a substituent, an aryl group capable of having a substituent, an aralkyl group capable of having a substituent, or a heterocyclic group capable of having a substituent, with the proviso that two or more imidazole units can be combined with each other via two of the groups R₁, R₂, R₃ and R₄ and an intervening bonding group selected from the group consisting of phenylene group, propenylene group, vinylene group, alkenylene group and alkylene group each capable of having a substituent; and

that R₃ and R₄ can be bonded to each other to form a saturated aliphatic ring, an unsaturated aliphatic ring, an aromatic ring or a heterocyclic ring.

58. The apparatus according to claim 57, wherein the toner contains a tetrahydrofuran (THF)-soluble content exhibiting a molecular weight distribution according to gel permeation chromatography (GPC) providing a number-average molecular weight (Mn) of 10³-4×

10⁴, and a weight-average molecular weight (Mw) of 10⁴-10⁷.

59. The apparatus according to claim 57, wherein the toner contains a tetrahydrofuran (THF)-soluble content providing a GPC (gel permeation chromatography) chromatogram exhibiting a main peak in a molecular weight region of 4×

10³-3×

10⁴.

60. The apparatus according to claim 59, wherein the GPC chromatogram exhibits a peak area in a molecular weight region of at most 3×

10⁴ which occupies 60-100% of an entire peak area on the GPC chromatogram.

61. The apparatus according to claim 57, wherein the toner contains a tetrahydrofuran (THF)-soluble content providing a GPC (gel permeation chromatography) chromatogram exhibiting at least one peak each in a molecular weight region of 4×

10³-3×

10⁴ and in a molecular weight region of 10⁵-10⁷.

62. The apparatus according to claim 57, wherein the toner contains a tetrahydrofuran (THF)-soluble content providing a GPC (gel permeation chromatography) chromatogram exhibiting at least one peak each in a molecular weight region of 4×

10³-3×

10⁴ and in a molecular weight region of 8×

10⁵-10⁷.

63. The apparatus according to claim 57, wherein the toner contains a tetrahydrofuran (THF)-soluble content providing a GPC (gel permeation chromatography) chromatogram exhibiting at least one peak each in a molecular weight region of 4×

10³-3×

10⁴, in a molecular weight region of 10⁵ to below 8×

10⁵, and in a molecular weight region of 8×

10⁵-10⁷.

64. The apparatus according to claim 63, wherein the GPC chromatogram exhibits a peak area in a molecular weight region of at least 10⁵ which occupies 5-40% of an entire peak area on the GPC chromatogram.

65. The apparatus according to claim 57, wherein the binder resin contains a THF-insoluble content of 0.1-60 wt. %.

66. The apparatus according to claim 57, wherein binder resin contains a THF-insoluble content of 5-60 wt. %.

67. The apparatus according to claim 57, wherein the binder resin contains a THF-insoluble content of 7-55 wt. %.

68. The apparatus according to claim 57, wherein binder resin contains a THF-insoluble content of 9-50 wt. %.

69. The apparatus according to claim 57, wherein the binder resin contains a THF-insoluble content of 10-45 wt. %.

70. The apparatus according to claim 57, wherein the toner contains a THF-soluble content having an acid value of 0.1-50 mgKOH/g.

71. The apparatus according to claim 57, wherein the toner contains a THF-soluble content having an acid value of 0.5-50 mgKOH/g.

72. The apparatus according to claim 57, wherein the toner contains a THF-soluble content having an acid value of 0.5-40 mgKOH/g.

73. The apparatus according to claim 57, wherein the toner contains a THF-soluble content having an acid value of 0.5-30 mgKOH/g.

74. The apparatus according to claim 57, wherein the toner contains a THF-soluble content having an acid value of 0.5-25 mgKOH/g.

75. The apparatus according to claim 57, wherein the toner contains a THF-soluble content having an acid value of 0.5-20 mgKOH/g.

76. The apparatus according to claim 57, wherein the toner has a storage modulus at 80°

C. (G′

(80°

C.)) of 1.0×

10⁵-2.0×

10⁶ Pa, and a storage modulus at 140°

C. (G′

(140°

C.)) of 1.0×

10³-2.0×

10⁴ Pa.

77. The apparatus according to claim 57, wherein the toner has a temperature giving a lose tangent (tan δ

) (=loss modulus/storage modulus) of 1 in a region of 90-130°

C., a loss tangent at 80°

C. (tan δ

(80°

C.)) of larger than 1, and a loss tangent at 140°

C. (tan δ

(140°

C.)) of smaller than 1.

78. The apparatus according to claim 57, wherein the toner has a storage modulus at 80°

C. (G′

(80°

C.)) of 1.0×

10⁵-2.0×

10⁶ Pa, a storage modulus at 140°

C. (G′

(140°

C.)) of 1.0×

10³-2.0×

10⁴ Pa, a temperature giving a loss tangent (tan δ

) (=loss modulus/storage modulus) of 1 in a region of 90-130°

C., a loss tangent at 80°

C. (tan δ

(80°

C.)) of larger than 1, and a loss tangent at 140°

C. (tan δ

(140°

C.)) of smaller than 1.

79. The apparatus according to claim 57, wherein the toner has been obtained through a step of melt-kneading at least the binder resin, the imidazole compound and the colorant under heating, and the toner has a storage modulus at 80°

C. (G′

(80°

C.)) of 1.0×

10⁵-2.0×

10⁶ Pa, and a storage modulus at 140°

C. (G′

(140°

C.)) of 1.0×

10³-2.0×

10⁴ Pa.

80. The apparatus according to claim 57, wherein the toner has been obtained through a stop of melt-kneading at least the binder resin, the imidazole compound and the colorant under heating, and the toner has a temperature giving a loss tangent (tan δ

) (=lose modulus/storage modulus) of 1 in a region of 90-130°

C., a loss tangent at 80°

C. (tan δ

(80°

C.)) of larger than 1, and a loss tangent at 140°

C. (tan δ

(140°

C.)) of smaller than 1.

81. The apparatus according to claim 57, wherein the toner has been obtained through a step of melt-kneading at least the binder resin, the imidazole compound and the colorant under heating, and the toner has a storage modulus at 80°

C. (G′

(80°

C.)) of 1.0×

10⁵-2.0×

10⁶ Pa, a storage modulus at 140°

C. (G′

(140°

C.)) of 1.0×

10³-2.0×

10⁴ Pa, a temperature giving a loss tangent (tan δ

) (=loss modulus/storage modulus) of 1 in a region of 90-130°

C., a loss tangent at 80°

C. (tan δ

(80°

C.)) of larger than 1, and a loss tangent at 140°

C. (tan δ

(140°

C.)) of smaller than 1.

82. The apparatus according to claim 57, wherein the developer-carrying member is in the form of a cylindrical sleeve formed of a material comprising a resin.

83. The apparatus according to claim 57, wherein the developer-carrying member comprises a substrate and a resin-containing coating layer formed on the substrate.

84. The apparatus according to claim 83, wherein the coating layer comprises at least one member selected from the group consisting of an electroconductive substrate, a filler and a solid lubricant, in addition to the resin.

85. The apparatus according to claim 57, wherein the image-bearing member comprises an electrophotographic photosensitive member.

86. The apparatus according to claim 57, further including a developing bias voltage application means for applying a developing bias voltage comprising an alternating voltage to the developer-carrying member.

87. The apparatus according to claim 86, wherein the developing bias voltage comprises an AC voltage superposed with a DC voltage.