Sheet processing device and image forming device provided with the same

1. A sheet processing device that binds sheets having different shapes and then folds the sheets, comprising:

a receiving tray capable of accommodating therein a sheet having a protruding portion at a part thereof and a sheet not having the protruding portion in a mixed state;

a regulating member that regulates a leading end of the sheet accommodated in the receiving tray;

a first binding member that binds a sheet bundle regulated by the regulating member at a substantially center thereof in a sheet conveying direction with a staple needle;

a folding section that folds the sheet bundle bound by the first binding member in two;

a second binding member that applies a pressure from a thickness direction of the sheet bundle to deform and performs a pressure-bonding binding on protruding portions of the sheet bundle folded by the folding section on a fore edge side of the sheet bundle;

a detection member that detects presence or absence of the protruding portion of the sheets to be conveyed to the receiving tray; and

a controller that issues an alarm signal when the detection member detects the sheet having the protruding portion is not accommodated in the receiving tray in a mode in which the first binding member is configured to bind the mixed sheets and after the mixed sheets are folded, the second binding member is configured to bind the protruding portions of the resultant sheet bundle.

2. The sheet processing device according to claim 1 , wherein

the sheet having the protruding portion at a part thereof is a sheet having a tab at least in the sheet conveying direction, and the sheet is accompanied in the receiving tray.

3. The sheet processing device according to claim 2 , further comprising a pressing member that is disposed downstream of the folding section in the sheet conveying direction and presses the folded sheet bundle from the thickness direction of the sheet bundle when the pressure-bonding binding is performed by the second binding member.

4. The sheet processing device according to claim 3 , wherein

the pressing member is constituted of a roller pair and configured to convey a saddle-stitched sheet bundle in a sheet discharge direction and to press the sheet bundle with a larger force than that at a conveying time when the binding is performed by the second binding member.

5. The sheet processing device according to claim 4 , wherein

the sheet with the tab is positioned at an outermost side of the sheet bundle to be folded.

6. The sheet processing device according to claim 4 , wherein

the sheets with the tabs are inserted between sheets without the tabs so as to sandwich the sheets without the tabs therebetween, and the resultant sheet bundle is accommodated in the receiving tray.

7. The sheet processing device according to claim 1 , wherein

after the issuance of the alarm signal, the sheets are discharged from the receiving tray after being folded without execution of sheet binding by the first or second binding member.

8. The sheet processing device according to claim 1 , wherein

after the issuance of the alarm signal, the sheet bundle is bound by the first binding member, folded, and then discharged from the receiving tray without execution of sheet binding by the second binding member.

9. An image forming device comprising:

an image forming section that sequentially forms an image onto sheets; and

a sheet processing device that applies predetermined processing onto the sheets from the image forming section, wherein

the sheet processing device has a configuration as claimed in claim 1 .

10. The sheet processing device according to claim 3 , wherein the pressing member comprises a roller pair and configured to convey a saddle-stitched sheet bundle in a sheet discharge direction and to stop a conveyance of the sheet bundle when the binding is performed by the second binding member.