Carrier for electrophotography, two-component type developer, and image forming method

Claim 2

The carrier according to claim 1, wherein said carrier particle has silicon atoms and carbon atoms on its surface in the ratio that satisfies the condition of: Si/C = 0.1 to 0.7 as the number of atoms present on the carrier particle surface as measured by X-ray photoelectron spectroscopy.

Claim 3

The carrier according to claim 1, wherein the silicone resin that forms said silicone resin coat layer contains an aminosilane coupling agent.

Claim 4

The carrier according to claim 2, wherein said silicone resin that forms the silicone resin coat layer further contains a coupling agent represented by the formula: R 4-a -Si-Xa wherein R 4-a represents a vinyl group, a methacrylic group, an epoxy group, an amino group, a mercapto group or a derivative of any of these; and X represents a halogen atom or an alkoxyl group.

Claim 5

The carrier according to claim 1, wherein the silicone resin that forms said silicone resin coat layer contains an oxime type hardening agent represented by the formula: wherein R₅ represents a substituent selected from CH₃, C₂H₅, and derivatives thereof; and R₆ and R₇ each represent a substituent selected from CH₃, C₂H₅ and derivatives thereof.

Claim 6

The carrier according to claim 5, wherein said silicone resin contains the oxime type hardening agent in an amount of from 0.1 part by weight to 10 parts by weight based on 100 parts by weight of siloxane solid content.

Claim 7

The carrier according to claim 1, wherein the silicone resin layer has a coating weight that satisfies the following relation, when coating weight based on 100 g of carrier cores is represented by a g, and specific surface area of the carrier particles formed after coating is represented by S cm²/g: (a/S) × 10⁴ = 2 to 30 where a is 0.01 to 1.0.

Claim 8

The carrier according to claim 1, wherein the silicone resin layer has a coating weight that satisfies the following relation, when coating weight based on 100 g of carrier cores is represented by a g, and specific surface area of the carrier particles formed after coating is represented by S cm²/g: (a/S) × 10⁴ = 5 to 20 where a is 0.01 to 1.0.

Claim 9

The carrier according to claim 1, wherein said carrier has a specific surface area of from 280 cm²/g to 600 cm²/g.

Claim 10

The carrier according to claim 1, wherein said carrier has a specific surface area of from 300 cm²/g to 560 cm²/g.

Claim 11

The carrier according to claim 1, wherein said carrier has a weight average particle diameter of from 10 µm to 100 µm.

Claim 12

The carrier according to claim 1, wherein said carrier has a weight average particle diameter of from 25 µm to 65 µm.

Claim 13

The carrier according to claim 1, wherein said carrier has a weight average particle diameter of from 25 µm to 65 µm, and contains, in its weight distribution, 1 to 40% by weight of carrier particles with particle diameters of not smaller than 26 µm to smaller than 35 µm, 5 to 40% by weight of carrier particles with particle diameters of not smaller than 35 µm to smaller than 43 µm and not more than 2% by weight of carrier particles with particle diameters of not smaller than 74 µm.

Claim 14

The carrier according to claim 1, wherein said carrier has a weight average particle diameter of from 30 µm to 65 µm, and contains, in its weight distribution, 1 to 40% by weight of carrier particles with particle diameters of not smaller than 26 µm to smaller than 35 µm, 5 to 40% by weight of carrier particles with particle diameters of not smaller than 35 µm to smaller than 43 µm and not more than 2% by weight of carrier particles with particle diameters of not smaller than 74 µm.

Claim 15

The carrier according to claim 1, wherein said carrier has an electrical current value of from 20 µA to 150 µA when a voltage of 500 V is applied.

Claim 16

The carrier according to claim 1, wherein said carrier has an electrical current value of from 30 µA to 140 µA when a voltage of 500 V is applied.

Claim 17

The carrier according to claim 1, wherein said silicone resin coat layer is formed using a resin composition containing i) a silicone resin comprised of an aggregate of segments represented by the following Formulas (I) to (III) and ii) compounds represented by the following Formulas (IV) and (V). wherein R⁰ to R¹⁰ each represent a hydrocarbon group selected from a methyl group, an ethyl group, a phenyl group and a vinyl group; R represents a hydrocarbon group which may be substituted with an electron-donative group; and n represents an integer of 1 to 3.

Claim 18

The carrier according to claim 17, wherein said segments (I) to (III) are in the ratio that satisfies the condition of: (I)/(II+III) = 1/99 to 60/40 and (II)/(III) = 10/90 to 100/0.

Claim 19

The carrier according to claim 17, wherein said segments (I) to (III) are in the ratio that satisfies the condition of: (I)/(II+III) = 2/88 to 50/50 and (II)/(III) = 30/70 to 100/0.

Claim 20

The carrier according to claim 1, wherein said silicone resin coat layer contains an aminosilane coupling agent represented by the formula: R m Si-Y n wherein R represents an alkoxyl group, Y represents a hydrocarbon group containing an amino group, m represents an integer of 1 to 3, and n represents an integer of 3 to 1; and said carrier has a weight average particle diameter of from 25 µm to 60 µm and has an electrical current value of from 20 µA to 150 µA when a voltage of 500 V is applied.

Claim 21

A two-component type developer for developing electrostatic images, comprising a toner and a carrier; said carrier comprising carrier particles, and each carrier particle comprising a carrier core and a silicone resin coat layer that covers the carrier core, wherein; said carrier particle has silicon atoms and carbon atoms on its surface in the ratio that satisfies the condition of: Si/C = 0.1 to 2.0 as the number of atoms present on the carrier particle surface as measured by X-ray photoelectron spectroscopy; and from 0.1% by number to 5% by number of metal atoms are present on the carrier particle surface.

Claim 22

The two-component type developer according to claim 21, wherein said toner has an external additive with an average particle diameter of not larger than 0.2 µm.

Claim 23

The two-component type developer according to claim 21, wherein said toner has an external additive with an average particle diameter of from 0.002 µm to 0.2 µm.

Claim 24

The two-component type developer according to claim 21, wherein said toner has a weight average particle diameter of from 1 µm to 10 µm, and a surface-treated titanium oxide having a weight average particle diameter of from 0.01 to 0.2 µm is externally added to said toner.

Claim 25

The two-component type developer according to claim 21, wherein fine titanium oxide particles are externally added to said toner, and the fine titanium oxide particles have been surface-treated while hydrolyzing in an aqueous system a coupling agent represented by the formula: C n H 2n+1 -Si-(OC m H 2m+1 )₃ wherein n represents an integer of 3 to 12 and m represents an integer of 1 to 3; and have a weight average particle diameter of from 0.01 µm to 0.2 µm, have a hydrophobicity of from 40% to 80% and have a light transmittance of not less than 40% at 400 nm.

Claim 26

The two-component type developer according to claim 21, wherein said carrier particle has silicon atoms and carbon atoms on its surface in the ratio that satisfies the condition of: Si/C = 0.1 to 0.7 as the number of atoms present on the carrier particle surface as measured by X-ray photoelectron spectroscopy.

Claim 27

The two-component type developer according to claim 21, wherein the silicone resin that forms said silicone resin coat layer contains an aminosilane coupling agent.

Claim 28

The two-component type developer according to claim 22, wherein said silicone resin that forms the silicone resin coat layer further contains a coupling agent represented by the formula: R 4-a -Si-Xa wherein R 4-a represents a vinyl group, a methacrylic group, an epoxy group, an amino group, a mercapto group or a derivative of any of these; and X represents a halogen atom or an alkoxyl group.

Claim 29

The two-component type developer according to claim 21, wherein the silicone resin that forms said silicone resin coat layer contains an oxime type hardening agent represented by the formula: wherein R₅ represents a substituent selected from CH₃, C₂H₅, and derivatives thereof; and R₆ and R₇ each represent a substituent selected from CH₃, C₂H₅ and derivatives thereof.

Claim 30

The two-component type developer according to claim 29, wherein said silicone resin contains the oxime type hardening agent in an amount of from 0.1 part by weight to 10 parts by weight based on 100 parts by weight of siloxane solid content.

Claim 31

The two-component type developer according to claim 21, wherein the silicone resin layer has a coating weight that satisfies the following relation, when coating weight based on 100 g of carrier cores is represented by a g, and specific surface area of the carrier particles formed after coating is represented by S cm²/g: (a/S) × 10⁴ = 2 to 30 where a is 0.01 to 1.0.

Claim 32

The two-component type developer according to claim 21, wherein the silicone resin layer has a coating weight that satisfies the following relation, when coating weight based on 100 g of carrier cores is represented by a g, and specific surface area of the carrier particles formed after coating is represented by S cm²/g: (a/S) × 10⁴ = 5 to 20 where a is 0.01 to 1.0.

Claim 33

The two-component type developer according to claim 21, wherein said carrier has a specific surface area of from 280 cm²/g to 600 cm²/g.

Claim 34

The two-component type developer according to claim 21, wherein said carrier has a specific surface area of from 300 cm2/g to 560 cm2/g.

Claim 35

The two-component type developer according to claim 21, wherein said carrier has a weight average particle diameter of from 10 µm to 100 µm.

Claim 36

The two-component type developer according to claim 21, wherein said carrier has a weight average particle diameter of from 25 µm to 65 µm.

Claim 37

The two-component type developer according to claim 21, wherein said carrier has a weight average particle diameter of from 25 µm to 65 µm, and contains, in its weight distribution, 1 to 40% by weight of carrier particles with particle diameters of not smaller than 26 µm to smaller than 35 µm, 5 to 40% by weight of carrier particles with particle diameters of not smaller than 35 µm to smaller than 43 µm and not more than 2% by weight of carrier particles with particle diameters of not smaller than 74 µm.

Claim 38

The two-component type developer according to claim 21, wherein said carrier has a weight average particle diameter of from 30 µm to 65 µm, and contains, in its weight distribution, 1 to 40% by weight of carrier particles with particle diameters of not smaller than 26 µm to smaller than 35 µm, 5 to 40% by weight of carrier particles with particle diameters of not smaller than 35 µm to smaller than 43 µm and not more than 2% by weight of carrier particles with particle diameters of not smaller than 74 µm.

Claim 39

The two-component type developer according to claim 21, wherein said carrier has an electrical current value of from 20 µA to 150 µA when a voltage of 500 V is applied.

Claim 40

The two-component type developer according to claim 21, wherein said carrier has an electrical current value of from 30 µA to 140 µA when a voltage of 500 V is applied.

Claim 41

The two-component type developer according to claim 21, wherein said silicone resin coat layer is formed using a resin composition containing i) a silicone resin comprised of an aggregate of segments represented by the following Formulas (I) to (III) and ii) compounds represented by the following Formulas (IV) and (V). wherein R⁰ to R¹⁰ each represent a hydrocarbon group selected from a methyl group, an ethyl group, a phenyl group and a vinyl group; R represents a hydrocarbon group which may be substituted with an electron-donative group; and n represents an integer of 1 to 3.

Claim 42

The two-component type developer according to claim 41, wherein said segments (I) to (III) are in the ratio that satisfies the condition of: (I)/(II+III) = 1/99 to 60/40 and (II)/(III) = 10/90 to 100/0.

Claim 43

The two-component type developer according to claim 41, wherein said segments (I) to (III) are in the ratio that satisfies the condition of: (I)/(II+III) = 2/88 to 50/50 and (II)/(III) = 30/70 to 100/0.

Claim 44

The two-component type developer according to claim 21, wherein said silicone resin coat layer contains an aminosilane coupling agent represented by the formula: R m Si-Y n wherein R represents an alkoxyl group, Y represents a hydrocarbon group containing an amino group, m represents an integer of 1 to 3, and n represents an integer of 3 to 1; and said carrier has a weight average particle diameter of from 25 µm to 60 µm and has an electrical current value of from 20 µA to 150 µA when a voltage of 500 V is applied.

Claim 45

An image forming method comprising; rotationally transporting a two-component type developer having a toner and a carrier, onto a developer carrying member; and developing in a developing zone defined by a latent image bearing member and the developer carrying member provided opposingly thereto, a latent image beared on the latent image bearing member, using a toner of the two-component type developer carried on the developer carrying member; wherein; said carrier comprises carrier particles, and each carrier particle comprises a carrier core and a silicone resin coat layer that covers the carrier core; said carrier particle has silicon atoms and carbon atoms on its surface in the ratio that satisfies the condition of: Si/C = 0.1 to 2.0 as the number of atoms present on the carrier particle surface as measured by X-ray photoelectron spectroscopy; and from 0.1% by number to 5% by number of metal atoms are present on the carrier particle surface.

Claim 46

The image forming method according to claim 45, wherein in said developing zone a developing electric field is formed between the latent image bearing member and the developer carrying member by applying to the developer carrying member a first voltage for directing the toner from the latent image bearing member toward the developer carrying member, a second voltage for directing the toner from the developer carrying member toward the latent image bearing member and a third voltage intermediate between the first voltage and the second voltage, to develop the latent image beared on the latent image bearing member, using the toner of the two-component type developer carried on the developer carrying member.

Claim 47

The image forming method according to claim 46, wherein the time for which the third voltage intermediate between the first voltage and the second voltage is applied to the developer carrying member is made longer than the time (T₁) for which the first voltage for directing the toner from the latent image bearing member toward the developer carrying member and the second voltage for directing the toner from the developer carrying member toward the latent image bearing member are applied to the developer carrying member.

Claim 48

The image forming method according to claim 45, wherein in said developing zone an electric field in which the toner is directed from the latent image bearing member toward the developer carrying member and an electric field in which the toner is directed from the developer carrying member toward the latent image bearing member are formed at least once between the latent image bearing member and the developer carrying member, and thereafter an electric field in which the toner is directed from the developer carrying member toward the latent image bearing member in an image area of the latent image bearing member and an electric field in which the toner is directed from the latent image bearing member toward the developer carrying member in a non-image area of the latent image bearing member are formed to develop the latent image beared on the latent image bearing member, using the toner of the two-component type developer carried on the developer carrying member.

Claim 49

The image forming method according to claim 48, wherein the time for forming the electric field in which the toner is directed from the developer carrying member toward the latent image bearing member in an image area of the latent image bearing member and the electric field in which the toner is directed from the latent image bearing member toward the developer carrying member in a non-image area of the latent image bearing member is made longer than the total time (T₁) for forming the electric field in which the toner is directed from the latent image bearing member toward the developer carrying member and the electric field in which the toner is directed from the developer carrying member toward the latent image bearing member.

Claim 50

The image forming method according to claim 45, wherein said developer carrying member has a magnet roller built therein, and said two-component type developer is rotationally transported onto the developer carrying member while both the magnet roller and the developer carrying member are set rotary or while the magnet roller is set stationary and the developer carrying member is set rotary.

Claim 51

The image forming method according to claim 45, wherein; said developer carrying member has a magnet roller built therein, and said two-component type developer is rotationally transported onto the developer carrying member while both the magnet roller and the developer carrying member are set rotary or while the magnet roller is set stationary and the developer carrying member is set rotary; in said developing zone an electric field in which the toner is directed from the latent image bearing member toward the developer carrying member and an electric field in which the toner is directed from the developer carrying member toward the latent image bearing member are formed at least once between the latent image bearing member and the developer carrying member, and thereafter an electric field in which the toner is directed from the developer carrying member toward the latent image bearing member in an image area of the latent image bearing member and an electric field in which the toner is directed from the latent image bearing member toward the developer carrying member in a non-image area of the latent image bearing member are formed to develop the latent image beared on the latent image bearing member, using the toner of the two-component type developer carried on the developer carrying member, wherein the time for forming the electric field in which the toner is directed from the developer carrying member toward the latent image bearing member in an image area of the latent image bearing member and the electric field in which the toner is directed from the latent image bearing member toward the developer carrying member in a non-image area of the latent image bearing member is made longer than the total time (T₁) for forming the electric field in which the toner is directed from the latent image bearing member toward the developer carrying member and the electric field in which the toner is directed from the developer carrying member toward the latent image bearing member; said silicone resin coat layer of said carrier comprises a cross-linkable silicone resin containing an aminosilane coupling agent represented by the formula: R m Si-Y n wherein R represents an alkoxyl group, Y represents a hydrocarbon group containing an amino group, m represents an integer of 1 to 3, and n represents an integer of 3 to 1; and said carrier has a weight average particle diameter of from 25 µm to 60 µm and has an electrical current value of from 20 µA to 150 µA when a voltage of 500 V is applied; and said toner has a weight average particle diameter of from 1 µm to 10 µm, and a surface-treated titanium oxide having a weight average particle diameter of from 0.01 to 0.2 µm is externally added to said toner.

Claim 52

The image forming method according to claim 45, wherein said toner has an external additive with an average particle diameter of not larger than 0.2 µm.

Claim 53

The image forming method according to claim 45, wherein said toner has an external additive with an average particle diameter of from 0.002 µm to 0.2 µm.

Claim 54

The image forming method according to claim 45, wherein said toner has a weight average particle diameter of from 1 µm to 10 µm, and a surface-treated titanium oxide having a weight average particle diameter of from 0.01 to 0.2 µm is externally added to said toner.

Claim 55

The image forming method according to claim 45, wherein fine titanium oxide particles are externally added to said toner, and the fine titanium oxide particles have been surface-treated while hydrolyzing in an aqueous system a coupling agent represented by the formula: C n H 2n+1 -Si-(OC m H 2m+1 )₃ wherein n represents an integer of 3 to 12 and m represents an integer of 1 to 3; and have a weight average particle diameter of from 0.01 µm to 0.2 µm, have a hydrophobicity of from 40% to 80% and have a light transmittance of not less than 40% at 400 nm.

Claim 56

The image forming method according to claim 45, wherein said carrier particle has silicon atoms and carbon atoms on its surface in the ratio that satisfies the condition of: Si/C = 0.1 to 0.7 as the number of atoms present on the carrier particle surface as measured by X-ray photoelectron spectroscopy.

Claim 57

The image forming method according to claim 45, wherein the silicone resin that forms said silicone resin coat layer contains an aminosilane coupling agent.

Claim 58

The image forming method according to claim 56, wherein said silicone resin that forms the silicone resin coat layer further contains a coupling agent represented by the formula: R 4-a -Si-Xa wherein R 4-a represents a vinyl group, a methacrylic group, an epoxy group, an amino group, a mercapto group or a derivative of any of these; and X represents a halogen atom or an alkoxyl group.

Claim 59

The image forming method according to claim 45, wherein the silicone resin that forms said silicone resin coat layer contains an oxime type hardening agent represented by the formula: wherein R₅ represents a substituent selected from CH₃, C2H5, and derivatives thereof; and R6 and R7 each represent a substituent selected from CH₃, C₂H₅ and derivatives thereof.

Claim 60

The image forming method according to claim 59, wherein said silicone resin contains the oxime type hardening agent in an amount of from 0.1 part by weight to 10 parts by weight based on 100 parts by weight of siloxane solid content.

Claim 61

The image forming method according to claim 45, wherein the silicone resin layer has a coating weight that satisfies the following relation, when coating weight based on 100 g of carrier cores is represented by a g, and specific surface area of the carrier particles formed after coating is represented by S cm²/g: (a/S) × 10⁴ = 2 to 30 where a is 0.01 to 1.0.

Claim 62

The image forming method according to claim 45, wherein the silicone resin layer has a coating weight that satisfies the following relation, when coating weight based on 100 g of carrier cores is represented by a g, and specific surface area of the carrier particles formed after coating is represented by S cm²/g: (a/S) × 10⁴ = 5 to 20 where a is 0.01 to 1.0.

Claim 63

The image forming method according to claim 45, wherein said carrier has a specific surface area of from 280 cm²/g to 600 cm²/g.

Claim 64

The image forming method according to claim 45, wherein said carrier has a specific surface area of from 300 cm²/g to 560 cm²/g.

Claim 65

The image forming method according to claim 45, wherein said carrier has a weight average particle diameter of from 10 µm to 100 µm.

Claim 66

The image forming method according to claim 45, wherein said carrier has a weight average particle diameter of from 25 µm to 65 µm.

Claim 67

The image forming method according to claim 45, wherein said carrier has a weight average particle diameter of from 25 µm to 65 µm, and contains, in its weight distribution, 1 to 40% by weight of carrier particles with particle diameters of not smaller than 26 µm to smaller than 35 µm, 5 to 40% by weight of carrier particles with particle diameters of not smaller than 35 µm to smaller than 43 µm and not more than 2% by weight of carrier particles with particle diameters of not smaller than 74 µm.

Claim 68

The image forming method according to claim 45, wherein said carrier has a weight average particle diameter of from 30 µm to 65 µm, and contains, in its weight distribution, 1 to 40% by weight of carrier particles with particle diameters of not smaller than 26 µm to smaller than 35 µm, 5 to 40% by weight of carrier particles with particle diameters of not smaller than 35 µm to smaller than 43 µm and not more than 2% by weight of carrier particles with particle diameters of not smaller than 74 µm.

Claim 69

The image forming method according to claim 45, wherein said carrier has an electrical current value of from 20 µA to 150 µA when a voltage of 500 V is applied.

Claim 70

The image forming method according to claim 45, wherein said carrier has an electrical current value of from 30 µA to 140 µA when a voltage of 500 V is applied.

Claim 71

The image forming method according to claim 45, wherein said silicone resin coat layer is formed using a resin composition containing i) a silicone resin comprised of an aggregate of segments represented by the following Formulas (I) to (III) and ii) compounds represented by the following Formulas (IV) and (V). wherein R⁰ to R¹⁰ each represent a hydrocarbon group selected from a methyl group, an ethyl group,a phenyl group and a vinyl group; R represents a hydrocarbon group which may be substituted with an electron-donative group; and n represents an integer of 1 to 3.

Claim 72

The image forming method according to claim 71, wherein said segments (I) to (III) are in the ratio that satisfies the condition of: (I)/(II+III) = 1/99 to 60/40 and (II)/(III) = 10/90 to 100/0.

Claim 73

The image forming method according to claim 71, wherein said segments (I) to (III) are in the ratio that satisfies the condition of: (I)/(II+III) = 2/88 to 50/50 and (II)/(III) = 30/70 to 100/0.

Claim 74

The image forming method according to claim 45, wherein said silicone resin coat layer contains an aminosilane coupling agent represented by the formula: R m Si-Y n wherein R represents an alkoxyl group, Y represents a hydrocarbon group containing an amino group, m represents an integer of 1 to 3, and n represents an integer of 3 to 1; and said carrier has a weight average particle diameter of from 25 µm to 60 µm and has an electrical current value of from 20 µA to 150 µA when a voltage of 500 V is applied.