Binding unit, sheet processing device, and image forming device provided with them

1. A binding unit that crimp-binds placed sheets, comprising:

a pair of first and second pressurizing parts disposed on front and back sides of placed sheets and configured to crimp-bind the placed sheets;

a water reservoir provided on a back side of the first pressurizing part and configured to store water to be applied to the sheets; and

a pressurizing member that pressurizes the water in the water reservoir to apply the water to a sheet crimping range, wherein

the pair of first and second pressurizing parts includes first pressure teeth and second pressure teeth that crimp-bind the sheets interposed therebetween, and

the water reservoir and the pressurizing member are provided on the back side of the first pressure teeth.

2. The binding unit according to claim 1 , wherein

the water reservoir is a cylinder, and the pressurizing member is a piston to be inserted into the cylinder for pressurization.

3. The binding unit according to claim 2 , wherein

a cylinder guide to be inserted into the cylinder provided on the back side of the first pressure teeth together with the piston is provided radially outside the piston.

4. The binding unit according to claim 3 , wherein

the cylinder positioned on the back side of the first pressure teeth is formed integrally with the first pressure teeth and has a replenishment port through which the water reservoir is replenished with water to be stored in the water reservoir.

5. The binding unit according to claim 4 , wherein

when water is stored in the water reservoir, pressurization of the piston applies water and then presses the first pressure teeth to crimp the sheets; while when no water is stored in the water reservoir, pressurization of the piston applies the first pressure teeth without applying water.

6. The binding unit according to claim 5 , wherein

an elastic body that crimps the sheets together with the first pressure teeth and surrounds an area larger than an area where the first pressure teeth contact the sheets and a water application range by the pressurizing member is provided around the first pressure teeth.

7. The binding unit according to claim 6 , wherein

the first pressure teeth have, on a front side thereof, the elastic body that surrounds the first pressure teeth and are brought into pressure contact with the sheets by an elastic spring provided at a side of the cylinder on the back side of the first pressure teeth so as to press the elastic body to the sheets and then applies water in the water reservoir to the sheets.

8. The binding unit according to claim 7 , wherein

water supply holes allowing water from the water reservoir to be applied to a range surrounded by the elastic body are provided.

9. A binding that crimp-binds placed sheets, comprising:

a pair of first and second pressurizing parts disposed on front and back sides of placed sheets and configured to crimp-bind the placed sheets;

a water reservoir provided on a back side of the first pressurizing part and configured to store water to be applied to the sheets; and

a pressurizing member that pressurizes the water in the water reservoir to apply the water to a sheet crimping range, wherein

a water replenishment pump part that replenishes the water reservoir with water is provided in a frame in which a first pressure teeth and the water reservoir provided on a back side of the first pressure teeth are positioned so as to be adjacent to the first pressure teeth and the water reservoir, and

the water replenishment pump part includes a water replenishment tank part that stores water for replenishment, a water replenishment piston part that supplies water from the water replenishment tank part, a water replenishment head part that moves the water replenishment piston part, and a water replenishment joint part that joints the water replenishment tank part and the water reservoir and replenishes the water reservoir provided on the back side of the first pressure teeth with water.

10. The binding unit according to claim 9 , wherein

a pressurizing piston and the water replenishment head part are moved by moving members, respectively, and

the moving members are driven by a single drive motor.

11. The binding unit according to claim 10 , wherein

the moving members include a pressing plate that moves the piston and the water replenishment head part and a turning arm turned about a turning fulcrum mounted to the frame, the turning arm causing the pressing plate to move to press the piston and the replenishment head part.

12. The binding unit according to claim 11 , wherein

a drain pan that receives residual water generated when water in the water reservoir is applied to the sheets is provided on a back side of the second pressure teeth mating with the first pressure teeth.

13. A binding unit that crimp-binds placed sheets, comprising:

a pair of first and second pressurizing parts disposed on front and back sides of placed sheets and configured to crimp-bind the placed sheets;

a water reservoir provided on a back side of the first pressurizing part and configured to store water to be applied to the sheets; and

a pressurizing member that pressurizes the water in the water reservoir to apply the water to a sheet crimping range, wherein

the pair of first and second pressurizing parts includes first pressure teeth and second pressure teeth that crimp-bind the sheets interposed therebetween, and

the water reservoir is a cylinder, and the pressurizing member is a piston to be inserted into the cylinder for pressurization.

14. The binding unit according to claim 13 , wherein the water reservoir and the pressurizing member are provided on a back side of the first pressure teeth.