Sheet feed device feeding paper and image forming apparatus

1. A sheet feed device feeding paper comprising:

a loading platen loaded with sheets;

a ventilation section providing a first ventilation port for blowing air to float a first side of a sheet of one sheet of the sheets loaded on the loading platen, and a second ventilation port for blowing air to float a second side opposed to the first side; and

a control section for controlling the ventilation section;

wherein the first side is a side of a topmost of loaded envelopes and has a height that is lower than other sides, and

when envelopes are to be fed, the control section controls the ventilation section to change air volume of the first ventilation port and the second ventilation port in such a way to stop the blow of air from the second ventilation port and to blow air from the first ventilation port alone so as to float the first side more greatly than when sheets other than envelopes are fed.

2. The sheet feed device feeding paper of claim 1 ,

wherein the first ventilation port further comprises a front ventilation port which blows air to a front formed by the first side of the loaded sheets, and

a lateral ventilation port that blows air to a portion close to the first side on a lateral side formed by the sides each of which is a side of the loaded sheets adjacent to the first side of the loaded sheets.

3. The sheet feed device feeding paper of claim 1 , further comprising an operation display section to set envelopes or sheets other than envelopes, wherein the control section determines if a current feeding is an envelope feeding or not, based on information of the setting of the operation display section.

4. The sheet feed device feeding paper of claim 3 ,

wherein a position of a bonded portion of the envelope and a position of a flap of the envelope are set to the operation display section.

5. The sheet feed device feeding paper of claim 4 ,

wherein opening or closing of the flap is set through the operation display section, and the control section controls the ventilation section to change ventilation conditions in response to whether the flap is opened or closed.

6. The sheet feed device feeding paper of claim 1 , further comprising a sensor for detecting a height of an upper surface of the loaded sheets, wherein the control section checks a sensor signal to determine if the current feeding is an envelope feeding mode or not.

7. A sheet feed device feeding paper comprising:

a loading platen loaded with sheets;

a ventilation section providing a first ventilation port for blowing air to float a first side of a sheet of one sheet of the sheets loaded on the loading platen, and a second ventilation port for blowing air to float a second side opposed to the first side;

an operation display section to set envelopes or sheets other than envelopes; and

a control section for controlling the ventilation section,

wherein the control section determines if a current feeding is an envelope feeding or not, based on information of the setting of the operation display section,

wherein the first side is a side of a topmost of loaded envelopes, the side of which height is lower than other sides, and when envelopes are to be fed, the control section controls the ventilation section to change air volume of the first ventilation port and the second ventilation port so as to float the first side more greatly than when sheets other than envelopes are fed, and

wherein a position of a bonded portion of the envelope and a position of a flap of the envelope are set to the operation display section.

8. The sheet feed device feeding paper of claim 7 ,

wherein the control section controls the ventilation section in such a way that, when envelopes are to be fed, air volume blown from the first ventilation port is increased over air volume blown when sheets other than envelopes are to be fed.

9. The sheet feed device feeding paper of claim 7 ,

wherein, when envelopes are to be fed, the control section controls the ventilation section in such a way that stops the blow of air from the second ventilation port and blows air from the first ventilation port alone.

10. The sheet feed device feeding paper of claim 7 ,

wherein opening or closing of the flap is set through the operation display section, and

the control section controls the ventilation section to change ventilation conditions in response to whether the flap is opened or closed.

11. The sheet feed device feeding paper of claim 7 ,

wherein the first ventilation port further comprises a front ventilation port which blows air to a front formed by the first side of the loaded sheets, and a lateral ventilation port that blows air to a portion close to the first side on a lateral side formed by the sides each of which is a side of the loaded sheets adjacent to the first side of the loaded sheets.

12. A sheet feed device feeding paper comprising:

a loading platen loaded with sheets;

a ventilation section providing a first ventilation port for blowing air to float a first side of a sheet of one sheet of the sheets loaded on the loading platen, and a second ventilation port for blowing air to float a second side opposed to the first side;

a sensor for detecting a height of an upper surface of the loaded sheets; and

a control section for controlling the ventilation section,

wherein the control section checks a sensor signal to determine if the current feeding is an envelope feeding mode or not, and

wherein the first side is a side of a topmost of loaded envelopes, the side of which height is lower than other sides, and, when envelopes are to fed, the control section controls the ventilation section to change air volume of the first ventilation port and the second ventilation port so as to float the first side more greatly than when sheets other than envelopes are fed.

13. The sheet feed device feeding paper of claim 12 ,

wherein the control section controls the ventilation section in such a way that, when envelopes are to be fed, air volume blown from the first ventilation port is increased over air volume blown when sheets other than envelopes are to be fed.

14. The image forming apparatus of claim 12 ,

wherein, when envelopes are to be fed, the control section controls the ventilation section in such a way that stops the blow of air from the second ventilation port and blows air from the first ventilation port alone.

15. The sheet feed device feeding paper of claim 12 ,

wherein the first ventilation port further comprises a front ventilation port which blows air to a front formed by the first side of the loaded sheets, and a lateral ventilation port that blows air to a portion close to the first side on a lateral side formed by the sides each of which is a side of the loaded sheets adjacent to the first side of the loaded sheets.

16. The sheet feed device feeding paper of claim 12 , further comprising an operation display section through which a position of a bonded portion of the envelope and a position of a flap of the envelope are set.

17. The sheet feed device feeding paper of claim 16

wherein opening and closing of the flap is set through the operation display section, and the control section controls the ventilation section to change ventilation conditions in response to whether the flap is opened or closed.

18. An image forming apparatus comprising:

a sheet feed device feeding paper; and

an image forming section for forming an image on the envelope supplied from the sheet feed device,

wherein the sheet feed device comprises;

a loading platen loaded with sheets;

a ventilation section providing a first ventilation port for blowing air to float a first side of a sheet of one sheet of the sheets loaded on the loading platen, and a second ventilation port for blowing air to float a second side opposed to the first side; and

a control section for controlling the ventilation section,

wherein the first side is a side of a topmost of loaded envelopes, the side of which height is lower than other sides, and when envelopes are to be fed, the control section controls the ventilation section to change air volume of the first ventilation port and the second ventilation port in such a way to stop the blow of air from the second ventilation port and to blow air from the first ventilation port alone so as to float the first side more greatly than in case when sheets other than envelopes are fed.

19. The image forming apparatus of claim 18 ,

wherein the first ventilation port further comprises a front ventilation port which blows air to a front formed by the first side of the loaded sheets, and

a lateral ventilation port that blows air to a portion close to the first side on a lateral side formed by the sides each of which is a side of the loaded sheets adjacent to the first side of the loaded sheets.

20. The image forming apparatus of claim 18 , further comprising an operation display section through which opening or closing of a flap of the envelope is set,

wherein the control section determines if a current feeding is an envelope feeding or not based on information of the setting of the operation display section, and a position of a bonded portion of the envelope and a position of the flap of the envelope are set to the operation display section.

21. An image forming apparatus comprising:

a sheet feed device feeding paper; and

an image forming section for forming an image on the envelope supplied from the sheet feed device,

wherein the sheet feed device comprises:

a loading platen loaded with sheets;

a ventilation section providing a first ventilation port for blowing air to float a first side of a sheet of one sheet of the sheets loaded on the loading platen, and a second ventilation port for blowing air to float a section side opposed to the first side;

an operation display section to set envelopes or sheets other than envelopes, and

a control section for controlling the ventilation section,

wherein the control section determines if a current feeding is an envelope feeding or not, based on information of the setting of the operation display section,

wherein the first side is a side of a topmost of loaded enveloped, the side of which height is lower than other sides, and, when envelopes are to be fed, the control section controls the ventilation section to change air volume of the first ventilation port and the second ventilation port so as to float the first side more greatly than when sheets other than envelopes are fed, and

wherein a position of a bonded portion of the envelope and a position of a flap of the envelope are set to the operation display section.

22. The image forming apparatus of claim 21 ,

wherein the control section controls the ventilation section in such a way that, when envelopes are to be fed, air volume blown from the first ventilation port is increased over air volume blown when sheets other than envelopes are to be fed.

23. The image forming apparatus of claim 21 ,

wherein, when envelopes are to be fed, the control section controls the ventilation section in such a way that stops the blow of air from the second ventilation port and blows air from the first ventilation port alone.

24. The image forming apparatus of claim 21 ,

wherein opening or closing of a flap of the envelope is set through the operation display section, and

the control section controls the ventilation section to change ventilation conditions in response to whether the flap is opened or closed.

25. An image forming apparatus comprising:

a sheet feed device feeding paper; and

an image forming section for forming an image on the envelope supplied from the sheet feed device,

wherein the sheet feed device comprises:

a loading platen loaded with sheets;

a ventilation section providing a first ventilation port for blowing air to float a first side of a sheet of one sheet of the sheets loaded on the loading platen, and a second ventilation port for blowing air to float a second side opposed to the first side;

a sensor for detecting a height of an upper surface of the loaded sheets; and

a control section for controlling the ventilation section,

wherein the first side is a side of a topmost of loaded envelopes and has a height that is lower than other sides, and, when envelopes are to be fed, the control section checks a sensor signal to determine if the current feeding is an envelope feeding mode or not and controls the ventilation section to change air volume of the first ventilation port and the second ventilation port so as to float the first side more greatly than when sheets other than envelopes are fed.