Stopper, paper feeding device and multi-function printer

A paper feeding device, comprising:

• an outer case, having a pair of side walls and a pair of limiting protrusions, wherein each limiting protrusion is correspondingly disposed at one of the pair of side walls;
• an inner case, located between the pair of side walls of the outer case, and each side wall is located between the inner case and the corresponding limiting protrusion;
• a first axel, pivoted between the inner case and the pair of side walls;
• a first roller, disposed around and covering the first axel and located in the inner case;
• a pair of stoppers, disposed at outer sides of the pair of side walls which are relatively distant from the inner case, wherein each stopper has a C-ring, a connecting portion and a stopping portion, the C-ring is disposed around and covers the first axel, the C-ring has a first end and a second end, the limiting protrusion props against the first end, the second end extends along a tangent direction and is connected to a third end of the connecting portion, the stopping portion is connected to a fourth end of the connecting portion, and an included angle is formed between the stopping portion and the connecting portion;
• a second axel, pivoted at the inner case, and located at a side of the inner case opposite to the first axel;
• a second roller, disposed around and covering the second axel, and located in the inner case;
• and
• a tray, disposed below the first roller and located in the inner case.

A multi-function printer, comprising:

• a body;
• a paper feeding device, disposed at the body and comprising:
• an outer case, covering the body, having a pair of side walls and a pair of limiting protrusions, wherein each limiting protrusion is correspondingly disposed at one of the pair of side walls;
• an inner case, located between the pair of side walls of the outer case, and each side wall is located between the inner case and the corresponding limiting protrusion;
• a first axel, pivoted between the inner case and the pair of side walls;
• a first roller, disposed around and covering the first axel and located in the inner case;
• a pair of stoppers, disposed at outer sides of the pair of side walls which are relatively distant from the inner case, wherein each stopper has a C-ring, a connecting portion and a stopping portion, the C-ring is disposed around and covers the first axel, the C-ring has a first end and a second end, the limiting protrusion props against the first end, the second end extends along a tangent direction and is connected to a third end of the connecting portion, the stopping portion is connected to a fourth end of the connecting portion, and an included angle is formed between the stopping portion and the connecting portion;
• a second axel, pivoted at the inner case, and located at a side of the inner case opposite to the first axel;
• a second roller, disposed around and covering the second axel, and located in the inner case;
• and
• a tray, disposed below the first roller and located in the inner case.