Conveying apparatus

1. A conveying apparatus comprising a plurality of rollers which are arranged in a conveying direction of a conveying target object and on which the conveying target object is to be placed, wherein

said plurality of rollers include a first roller and a second roller adjacent to said first roller,

said first roller comprises

a first placement portion on which the conveying target object is to be placed, and

a large diameter portion which has a larger diameter than that of said first placement portion and guides the conveying target object in the conveying direction, and

said second roller comprises

a second placement portion on which the conveying target object is to be placed,

a small diameter portion which has a smaller diameter than that of said second placement portion and prevents interference between said large diameter portion and said second roller, and

a gap between said first roller and said second roller is substantially uniform in a radial direction of said first and second rollers.

2. The conveying apparatus according to claim 1 , wherein said first roller and said second roller arranged closely to be in noncontact with each other.

3. The conveying apparatus according to claim 1 , wherein said first placement portion and said second placement portion have the same diameter.

4. The conveying apparatus according to claim 1 , wherein said plurality of rollers comprise said first roller and said second roller that are alternately arranged.

5. The conveying apparatus according to claim 1 , wherein said plurality of rollers are provided in two rows at a predetermined distance therebetween along the conveying direction.

6. The conveying apparatus according to claim 1 , further comprising driving means for applying a rotation force to said first and second rollers.

7. The conveying apparatus according to claim 6 , wherein said driving means comprises

an endless belt which is disposed under said first and second rollers and is in contact with said first and second placement sections, and

an auxiliary roller which presses said endless belt against said first and second placement sections.

8. The conveying apparatus according to claim 7 , wherein

said endless belt is disposed to travel along a vertical plane, and

said driving means further comprises

a driving roller which is arranged under said first and second rollers and causes said endless belt to travel.

9. The conveying apparatus according to claim 8 , wherein said driving means further comprises a tension adjusting mechanism which is arranged under said first and second rollers and adjusts a tension of said endless belt.

10. The conveying apparatus according to claim 6 , further comprising a support section which rotatably supports said plurality of rollers and stores and supports said driving means.

11. The conveying apparatus according to claim 10 , further comprising

cleaning means for cleaning air in said support section and discharging the air Outside.

12. The conveying apparatus according to claim 10 , further comprising pivoting means for pivoting said support section about a vertical axis.

13. The conveying apparatus according to claim 10 , further comprising elevating means for vertically moving said support section.

14. The conveying apparatus according to claim 1 further comprising a support section which rotatably supports said plurality of rollers,

wherein said support section forms a substantially hollow surrounding body having an upper surface which is open along the conveying direction to expose only upper portions of said plurality of rollers.