US 2008/0187338 A1Published application

Image forming apparatus

AssigneeCanon Kabushiki Kaisha

InventorsTakeshi Yamamoto, Manami Haraguchi, Kenta Kubo, Yoshinobu Baba, Koh Ishigami

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Abstract

An image forming apparatus, wherein the following formulae are satisfied: 0.22 ≤ ( M / S ) L ≤ 0.4 ,  ( Q M ) L = Vc ( Lt 2  ɛ 0  ɛ t + Ld ɛ 0  ɛ d ) × ( M S ) L ( Dt   max - Dt 0.1 ) { λ × ( M S ) L - 0.1 }  ( Lt 2  ɛ 0  ɛ t + Ld ɛ 0  ɛ d ) × ( M S ) L 500 ≤ αβ ≤ ( Dt   max - Dt 0.1 ) { λ × ( M S ) L - 0.1 }  ( Lt 2  ɛ 0  ɛ t + Ld ɛ 0  ɛ d ) × ( M S ) L 150 αβ ≥ ( Dt   max - Dt 0.1 ) { λ × ( M S ) L - 0.1 } 150 where (M/S)L: a toner bearing amount in a maximum density image portion of a photosensitive drum, (Q/M)L: an average charge amount of the toner in the maximum density portion, Vc: an absolute value of a potential difference between a DC-component of a developing bias and the maximum density portion, Lt: a toner layer thickness of the maximum density portion, Ld: a drum thickness, εt: a relative permittivity of the toner layer, εd: a relative permittivity of the drum, ε0: a vacuum permittivity, Dtmax: a transmission density in a maximum density image portion on the paper after fixation, Dt0.1: a transmission density in an image on the paper when the toner bearing amount on the paper after fixation is 0.1 mg/cm2, and λ: a transfer efficiency of the toner, α = ( Dt   max - Dt 0.1 ) { λ × ( M S ) L - 0.1 } ,  and   β = 1 / ( Q / M ) L .

An image forming apparatus, comprising:

a photosensitive member;
a developing device which develops an electrostatic image formed on the photosensitive member with a developer having a toner and a carrier, the developing device including a developer carrying member which carries and conveys the developer to a developing position;
a transfer device which transfers a toner image formed on the photosensitive member to a transfer material;
and
a fixing device which fixes the toner image on the transfer material to the transfer material,
wherein assuming that a toner bearing amount in a maximum density image portion of the photosensitive member is (M/S)L [mg/cm2], an average charge amount of the toner in the maximum density image portion of the photosensitive member is (Q/M)L [μC/g], an absolute value of a potential difference between a potential of a DC-component of a developing bias applied to the developer carrying member and a potential of the maximum density image portion on the photosensitive member is Vc [V], a toner layer thickness of the maximum density image portion on the photosensitive member is Lt [μm], a thickness of the photosensitive member is Ld [μm], a relative permittivity of the toner layer is εt, a relative permittivity of the photosensitive member is εd, a permittivity in vacuum is ε0, a transmission density in a maximum density image portion on the transfer material after being fixed by the fixing device is ⊃tmax, a transmission density in an image portion on the transfer material when the toner bearing amount on the transfer material after being fixed by the fixing device is 0.1 mg/cm2 is Dt0.1, and a transfer efficiency of the toner from the photosensitive member onto the transfer material is λ,
the following formulae are satisfied:
0.22<(M/S)L≦0.4,
(
Q
M
)
L
=
Vc
(
Lt
2

ɛ
0

ɛ
t
+
Ld
ɛ
0

ɛ
d
)
×
(
M
S
)
L
,
and assuming that
α
=
(
Dt


max
-
Dt
0.1
)
{
λ
×
(
M
S
)
L
-
0.1
}
,
and β=1/(Q/M)L,
the following formulae are satisfied:
(
Dt


max
-
Dt
0.1
)
{
λ
×
(
M
S
)
L
-
0.1
}

(
Lt
2

ɛ
0

ɛ
t
+
Ld
ɛ
0

ɛ
d
)
×
(
M
S
)
L
500
≤
αβ
≤
(
Dt


max
-
Dt
0.1
)
{
λ
×
(
M
S
)
L
-
0.1
}

(
Lt
2

ɛ
0

ɛ
t
+
Ld
ɛ
0

ɛ
d
)
×
(
M
S
)
L
150

αβ
=
(
Dt


max
-
Dt
0.1
)
{
λ
×
(
M
S
)
L
-
0.1
}
150
.

180 more elements

Facts

Application

12/022,575Filed 30 Jan 2008

Priority

JP 2007-0249252 Feb 2007

Published

7 Aug 2008

Term ends

Not estimatedThe source records don’t support an estimate.

Classification8 codes

G03G 15/065
For developing: arrangements for controlling the potential of the developing electrode
G03G 5/04
Charge-receiving layers: photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
G03G 15/0806
Using a solid developer, e.g. powder developer: on a donor element, e.g. belt, roller
G03G 15/5037
By measuring the photoconductor characteristics, e.g. temperature, or the characteristics of an image on the photoconductor: the characteristics…

Abstract

Claims8