Belt device, transferring unit and image forming device

1. A belt device, comprising:

an endless belt including at least a base layer and a coat layer, the coat layer formed on the base layer and configuring an upper most surface of the belt;

a driving member that is provided inside the belt to bias an inner circumferential surface of the belt, and that is configured to rotate the belt; and

a driven member that is provided inside the belt to bias the inner circumferential surface of the belt, and that is driven by the belt as the belt is rotated by the driving member, wherein

the base layer has a mirror specularity of 20-60, and

a layer thickness of the coat layer is 100 nm-500 nm.

2. The belt device according to claim 1 , wherein

the mirror specularity is determined based on a strength of reflection light with respect to a dark part and a light part of a test pattern that is projected on the belt.

3. The belt device according to claim 1 , wherein

a test pattern projected on the belt includes a plurality of slit-like shapes.

4. The belt device according to claim 1 , wherein

the mirror specularity is determined based on an average value of maximal values (Max(Ave)) that corresponds to a strength of reflection light for a light part and an average value of minimal values (Min(Ave)) that corresponds to a strength of reflection light for a dark part by using an expression as follows:

Mirror

⁢

⁢

Specularity

=

Max

⁡

(

Ave

)

-

Min

⁡

(

Ave

)

Max

⁡

(

Ave

)

+

Min

⁡

(

Ave

)

×

1000

Here

⁢

:

⁢

⁢

Max

⁡

(

Ave

)

=

∑

Max

⁡

(

n

)

n

⁢

Min

⁡

(

Ave

)

=

∑

Min

⁡

(

n

)

n

.

5. The belt device according to claim 1 , wherein

the mirror specularity of the base layer is 40-60.

6. The belt device according to claim 1 , wherein

the coat layer is made of a polymer.

7. The belt device according to claim 6 , wherein

the polymer is one selected from a group of poly-acrylic urethane, poly-acrylic, polyester-urethane, polyether-urethane, polycarbonate (PC), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), styrene compound, and naphthalene compound.

8. The belt device according to claim 6 , wherein

a thickness of the polymer is 100 nm-500 nm.

9. A transferring unit, comprising:

a belt device comprising:

an endless belt including at least a base layer and a coat layer, the coat layer formed on the base layer and configuring an upper most surface of the belt;

a driving member that is provided inside the belt to bias an inner circumferential surface of the belt, and that is configured to rotate the belt; and

a driven member that is provided inside the belt to bias the inner circumferential surface of the belt, and that is driven by the belt as the belt is rotated by the driving member, wherein

the base layer has a mirror specularity of 20-60,

a layer thickness of the coat layer is 100 nm-500 nm, and

a transferring roller is provided at an inner circumferential surface of the belt, on which a bias voltage is applied, and transfers a toner image to the belt or a recording medium provided on the belt.

10. The transferring unit according to claim 9 , further comprising:

an image density detection unit that include a light emitting element and a light receiving element and that detect a density of the transferred image by irradiating light from the light emitting element and receiving reflection light from the transferred tonner image based on the irradiated light.

11. The transferring unit according to claim 9 , wherein

the mirror specularity is determined based on a strength of reflection light with respect to a dark part and a light part of a test pattern that is projected on the belt.

12. The transferring unit according to claim 9 , wherein

the mirror specularity is determined based on an average value of maximal values (Max(Ave)) that corresponds to the strength of the reflection light for the light part and an average value of minimal values (Min(Ave)) that corresponds to the strength of the reflection light for the dark part by using an expression as follows:

Mirror

⁢

⁢

Specularity

=

Max

⁡

(

Ave

)

-

Min

⁡

(

Ave

)

Max

⁡

(

Ave

)

+

Min

⁡

(

Ave

)

×

1000

Here

⁢

:

⁢

⁢

Max

⁡

(

Ave

)

=

∑

Max

⁡

(

n

)

n

⁢

Min

⁡

(

Ave

)

=

∑

Min

⁡

(

n

)

n

.

13. The transferring unit according to claim 9 , wherein

the mirror specularity of the base layer is 40-60.

14. An image forming device, comprising:

the transferring unit according to claim 9 ;

a fusion unit that fuses the toner image by melting and pressing the toner image; and

an ejecting unit that receives the recording medium elected by the fusion unit.

15. An image forming device, comprising:

the transferring unit according to claim 9 ;

an image density detection unit that includes a light emitting element and a light receiving element and that detects a density of the transferred image by irradiating light from the light emitting element and by receiving reflection light from the transferred image based on the irradiated light; and

a control unit that receives an analog signal from the light receiving element, the analog signal corresponding to a strength of reflection light from the toner image, that converts the analog signal to a digital signal, that calculates a toner density of the toner image based on the digital signal, that calculates differences between the calculated toner density and a stored tone density that is predetermined and stored in a memory of the control unit, and that corrects the toner density.

16. The image forming device according to claim 14 , further comprising:

an image density detection unit that include a light emitting element and a light receiving element and that detect a density of the transferred image by irradiating light from the light emitting element and receiving reflection light from the transferred image based on the irradiated light.