This application claims the benefit of Taiwan application Serial No. 92132644, filed Nov. 20, 2003, the subject matter of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates in general to an automatic document feeder (ADF), and more particularly to an automatic document feeder which disposes a bearing board on an elastic structure of a sloping paper feeding tray.
2. Description of the Related Art
Referring to FIG. 1A, a cross-sectional view of the structure of a conventional automatic document feeder (ADF) is shown. In FIG. 1A, an automatic document feeder 100, which includes a horizontal paper feeding tray 104, an automatic paper feeding roller set 106, a paper supporting plate 108 and a spring 111, for feeding a to-be-fed paper sheet 102 into an office machine (not shown in FIG. 1A) such as a printer, a copier, a scanner or a facsimile machine is shown. The horizontal paper feeding tray 104 is for accommodating the to-be-fed paper sheet 102. A feeding end 112 is formed by a flange of the automatic paper feeding roller set 106 and a paper feeding pad 110, wherein the flange of the automatic paper feeding roller set 106 and the paper feeding pad 110 are adjacent to and in contact with each other. The automatic paper feeding roller set 106 rotates clockwise around the roller shaft 116 and carries the to-be-fed paper sheet 102 to move forward. The paper supporting plate 108, with its one end being pivotally connected to the horizontal paper feeding tray 104, is able to turn around on the horizontal paper feeding tray 104. One end of the spring 111 is fixed at a slot 113 of the horizontal paper feeding tray 104 while the other end of the spring 111 is fixed onto the bottom of the other end of the paper supporting plate 108, forming an included angle θ1 between the paper supporting plate 108 and the horizontal paper feeding tray 104.
Referring to FIG. 1B, a cross-sectional view of the structure of the automatic document feeder of FIG. 1A with a paper stack 114 being loaded therein is shown. In FIG. 1B, the paper stack 114 is placed on the horizontal paper feeding tray 104, wherein the paper stack 114 includes a paper sheet 102a, a paper sheet 102b, a paper stack 114a and a paper sheet 102c according to a top-down arrangement. Since the gravity of the paper stack 114 is much larger than that of the single to-be-fed paper sheet 102 in FIG. 1A, the included angle between the paper supporting plate 108 and the horizontal paper feeding tray 104 in FIG. 1B is smaller than the included angle θ1 in FIG. 1A. Furthermore, since the paper stack 114 weighs heavier, the spring 111 must have a larger elasticity so that the front end of the paper stack 114 may be raised up to the paper feeding pad 110 with the front end of the paper sheet 102a just reaching the feeding end 112.
After the automatic paper feeding roller set 106 has fed the paper sheets 102a and 102b and the paper stack 114a into the office machine in succession, only the paper sheet 102c will be left in the horizontal paper feeding tray 104 like the case in FIG. 1A. By means of the upward elasticity of the spring 111, the included angle between the paper supporting plate 108 and the horizontal paper feeding tray 104 is expanded to be θ1, so that the paper sheet 102c is raised up with the front end of the paper sheet 102c reaching the feeding end 112. Consequently, the automatic paper feeding roller set 106 may carry the paper sheet 102c towards the feeding end 112. The step of automatic document feeding of the automatic document feeder 100 is completed here.
Since the structure of the horizontal paper feeding tray 104 adopts a horizontal design, the spring 111 must provide an upward elasticity to support the weight of the paper sheets and to enable the paper supporting plate 108 to raise the paper sheets up so that the front ends of the paper sheets may reach the feeding end 112. When the number of paper sheets placed on the paper supporting plate 108 becomes larger, the elasticity of the spring 111 needs to be enhanced accordingly to assure that the topmost paper sheet may reach the feeding end 112. Since the assembly mechanism of the horizontal paper feeding tray 104, the spring 111 and the paper supporting plate 108 is very complicated, the assembly is costly and is difficult to be done during the manufacturing process.
Referring to FIG. 2A, a cross-sectional view of the structure of an automatic document feeder 200 disclosed in Taiwanese patent publication number 509143 is shown. In FIG. 2A, an automatic document feeder 200, which includes a sloping paper feeding tray 204, a automatic paper feeding roller set 206 and a Mylar 208, is for feeding a to-be-fed paper sheet 202 into an office machine (not shown in FIG. 2A) such as a printer, a copier, a scanner or a facsimile machine is shown. The sloping paper feeding tray 204 is for accommodating the to-be-fed paper sheet 202. Both the automatic paper feeding roller set 206 and the paper feeding pad 210 are disposed at the bottom of the sloping paper feeding tray 204. A feeding end 212 is formed by a flange of the automatic paper feeding roller set 206 and the paper feeding pad 210, wherein the flange of the automatic paper feeding roller set 206 and the paper feeding pad 210 are adjacent to and in contact with each other. Moreover, the automatic paper feeding roller set 206 rotates clockwise around a roller shaft 216 and carries the to-be-fed paper sheet 202 to move forward. The Mylar 208 further includes a junction portion 208a and a supporting portion 208b, wherein the junction portion 208a is flatly adhered onto the sloping paper feeding tray 204 while an included angle β1 is formed between the supporting portion 208b and the sloping paper feeding tray 204. As more paper sheets are placed on the Mylar 208, the included angle between the supporting portion 208b and the sloping paper feeding tray 204 becomes smaller. By means of the structural elasticity, the Mylar 208 is able to support the to-be-fed paper sheet 202. Availed by the sloping design of the structure of the sloping paper feeding tray 204, the front end of the to-be-fed paper sheet 202 may slide to reach the feeding end 212 due to gravity, so that the automatic paper feeding roller set 206 may carry the to-be-fed paper sheet 202 to move towards the feeding end 212.
Referring to FIG. 2B, a cross-sectional view of the structure of an automatic document feeder 200 in FIG. 2A with a paper stack 214 being loaded therein is shown. In FIG. 2B, the paper stack 214 including two paper sheets 202a and 202b, a paper stack 214a and a paper sheet 202c arranged in a top-down order is loaded in a sloping paper feeding tray 204. Since the downward gravity of the paper stack 214 is larger than the gravity of the single to-be-fed paper sheet 202 in FIG. 2A and the upward elasticity of the Mylar 208 as well, the included angle between the supporting plate 208b and the sloping paper feeding tray 204 is smaller than β1. Furthermore, the bottom of the supporting portion 208b of the Mylar 208 may come into contact with the sloping paper feeding tray 204. Meanwhile, the front end of the paper stack 214 comes into contact with the paper feeding pad 210 with the front end of the paper sheet 202a just reaching the feeding end 212.
After the paper sheets 202a and 202b and the paper stack 214a are sequentially carried by the paper feeding roller set 206 and fed into the office machine, only the paper sheet 202c will be left on the sloping paper feeding tray 204 like the case in FIG. 2A. Owing to the upward elasticity of the Mylar 208, the included angle between the supporting portion 208b and the sloping paper feeding tray 204 is expanded and becomes β1 so that the paper sheet 202c is raised upward with the front end of the paper sheet 202c reaching the feeding end 212. Consequently, the automatic paper feeding roller set 206 may carry the paper sheet 202c to move towards the feeding end 212. The step of automatic document feeding of the automatic document feeder 200 is completed here.
However, the Mylar 208, which has a fragile structure and is directly exposed on the sloping paper feeding tray 204, will be easily worn out in the long run and is likely to be damaged by a careless operator. Once the Mylar 208 is damaged, the automatic document feeder 200 cannot function properly and needs to be repaired, boosting the repair and maintenance cost even higher.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide an automatic document feeder whose design of disposing a bearing board on a sloping paper feeding tray not only protects the Mylar disposed under the supporting plate from being damaged but also reduces the damage rate of the Mylar, so that the lifespan of the Mylar may be lengthened and a stable operation of the automatic document feeder may be achieved
It is therefore another object of the invention to provide an automatic document feeder including a sloping paper feeding tray, a bearing board and an elastic structure. The sloping paper feeding tray is for accommodating a to-be-fed paper sheet. The bearing board, with its one end being pivotally connected to the sloping paper feeding tray, is able to turn around on the sloping paper feeding tray, while the other end of the bearing board supports the to-be-fed paper sheet. The elastic structure, which is disposed between the sloping paper feeding tray and the bearing board, elastically supports the other end of the bearing board to create an included angle between the supporting plate and the sloping paper feeding tray. The elastic structure may be a Mylar or a spring for instance.
It is therefore another object of the invention to provide an automatic document feeder including a sloping paper feeding tray, a bearing board and a Mylar. The sloping paper feeding tray is for accommodating a to-be-fed paper sheet. The bearing board, with its one end being pivotally connected to the sloping paper feeding tray, is able to turn around on the sloping paper feeding tray, while the other end of the bearing board supports the to-be-fed paper sheet. The Mylar, which is disposed between the sloping paper feeding tray and the supporting plate, may elastically spring the other end of the bearing board so that an included angle is created between the bearing board and the sloping paper feeding tray. The Mylar includes a junction portion and a supporting portion with the junction portion being flatly adhered onto the sloping paper feeding tray. The supporting portion, which creates another included angle with the sloping paper feeding tray, elastically supports the bearing board.
Other objects, features, and advantages of the invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A shows a cross-sectional view of the structure of a conventional automatic document feeder;
FIG. 1B shows a cross-sectional view of the structure of the automatic document feeder of FIG. 1A with a paper stack being loaded therein;
FIG. 2A shows a cross-sectional view of the structure of an automatic document feeder 200 disclosed in Taiwanese patent publication number 509143;
FIG. 2B shows a cross-sectional view of the structure of an automatic document feeder 200 in FIG. 2A with a paper stack 214 being loaded therein;
FIG. 3A shows a cross-sectional view of the structure of an automatic document feeder according to preferred embodiment one of the invention;
FIG. 3B shows a cross-sectional view of the structure of the automatic document feeder of FIG. 3A with a paper stack being loaded therein;
FIG. 4A shows a cross-sectional view of the structure of an automatic document feeder according to preferred embodiment two of the invention; and
FIG. 4B shows a cross-sectional view of the structure of the automatic document feeder of FIG. 4A with a paper stack being loaded therein.
DETAILED DESCRIPTION OF THE INVENTION
PREFERRED EMBODIMENT ONE
Referring to FIG. 3A, a cross-sectional view of the structure of an automatic document feeder 300 according to preferred embodiment one of the invention is shown. In FIG. 3A, the automatic document feeder 300 includes a sloping paper feeding tray 304, an automatic paper feeding roller set 306, a paper feeding pad 310, a bearing board 307 and an elastic structure, wherein the elastic structure may be a spring or a Mylar 308. The automatic document feeder 300 is for feeding a to-be-fed paper sheet 302 into an office machine (not shown in FIG. 3A) such as a printer, a copier, a scanner or a facsimile machine. The sloping paper feeding tray 304 is for accommodating the to-be-fed paper sheet 302. Both the automatic paper feeding roller set 306 and the paper feeding pad 310 are disposed at the bottom of the sloping paper feeding tray 304. A feeding end 312 is formed by a flange of the automatic paper feeding roller set 306 and the paper feeding pad 310, wherein the flange of the automatic paper feeding roller set 306 and the paper feeding pad 310 are adjacent to and in contact with each other. Moreover, the automatic paper feeding roller set 306 rotates clockwise around a roller shaft 316 and carries the to-be-fed paper sheet 302 to move forward.
The bearing board 307, with its one end being pivotally connected to the sloping paper feeding tray 304, is able to turn around on the sloping paper feeding tray, while the other end of the bearing board 307 supports the to-be-fed paper sheet 302. The Mylar 308, which is disposed between the sloping paper feeding tray 304 and the bearing board 307, may elastically spring the other end of the bearing board 307 so that an included angle ω1 is created between the bearing board and the sloping paper feeding tray.
The Mylar 308 includes a junction portion 308a and a supporting portion 308b with the junction portion 308a being flatly adhered onto the sloping paper feeding tray 304. The supporting portion 308b, which creates another included angle with the sloping paper feeding tray 304, elastically supports the bearing board 307. As more and more paper sheets are placed on the bearing board 307, the included angle between the bearing board 307 and the sloping paper feeding tray 304 becomes smaller and so does the included angle between the supporting portion 308b and the sloping paper feeding tray 304. The bearing board 307 uses the elasticity of the Mylar 308 to support the to-be-fed paper sheet 302 with the front end of the to-be-fed paper 302 reaching the feeding end 312, so that the automatic paper feeding roller set 306 may carry the to-be-fed paper sheet 302 to move towards the feeding end 312.
Referring to FIG. 3B, a cross-sectional view of the structure of the automatic document feeder of FIG. 3A with a paper stack being loaded therein is shown. In FIG. 3B, the paper stack 314 including a paper sheet 302a, a paper sheet 302b, a paper stack 314a and a paper sheet 302c arranged in a top-down order is loaded in a sloping paper feeding tray 304. Since the downward gravity of the paper stack 314 is larger than the gravity of the single to-be-fed paper sheet 302 in FIG. 3A and the upward elasticity of the Mylar 308 as well, the included angle between the bearing board 307 and the sloping paper feeding tray 304 is smaller than ω1. Furthermore, the bottom of the supporting portion 308b of the Mylar 308 may even come into contact with the sloping paper feeding tray 304. Meanwhile, the front end of the paper stack 314 comes into contact with the paper feeding pad 310 and the front end of the paper sheet 302a just reaches the feeding end 312.
When the automatic paper feeding roller set 306 starts to rotate around a roller shaft 316, the automatic paper feeding roller set 306 will carry the paper sheet 302a to move towards the feeding end 312 because the front end of the paper sheet 302a has reached the feeding end 312 already. After the paper sheet 302a has completely passed through the feeding end 312 and is carried forward by the automatic paper feeding roller set 306, the upward elasticity of the Mylar 308 will bring the front end of the paper sheet 302b to reach the feeding end 312 to be carried forward by the automatic paper feeding roller set 306 like the case mentioned above. When fewer and fewer paper sheets are left at the paper stack 314, the downward gravity of the paper stack 314 becomes smaller and smaller accordingly. Owing to the upward elasticity of the Mylar 308, the included angle between the bearing board 307 and the sloping paper feeding tray 304 will become larger and larger to support the weight of the remaining paper sheets of the paper stack 314. Consequently, the front end of the remaining paper sheets of the paper stack 314 will reach the feeding end 312 sequentially, so that the automatic paper feeding roller set 306 may sequentially carry the paper sheets of the paper stack 314 to move forward.
After the paper sheets 302a and 302b and the paper stack 314a are sequentially carried by the paper feeding roller set 306 and fed into the office machine, only the paper sheet 302c will be left at the sloping paper feeding tray 204 like the case in FIG. 3A. Owing to the upward elasticity of the Mylar 308, the included angle between the bearing board 307 and the sloping paper feeding tray 304 is expanded and becomes ω1 so that the paper sheet 302c is pushed upward with the front end of the paper sheet 302c reaching the feeding end 312. Consequently, the automatic paper feeding roller set 306 may carry the paper sheet 302c to move towards the feeding end 312. The step of automatic document feeding of the automatic document feeder 300 is completed here.
PREFERRED EMBODIMENT TWO
Referring to FIG. 4A, a cross-sectional view of the structure of an automatic document feeder 400 according to preferred embodiment two of the invention is shown. In FIG. 4A, the automatic document feeder 400 includes a sloping paper feeding tray 404, an automatic paper feeding roller set 406, a paper feeding pad 410, a bearing board 407 and an elastic structure, wherein the elastic structure may be a spring or a Mylar 408. The automatic document feeder 400 is for feeding a to-be-fed paper sheet 402 into an office machine (not shown in FIG. 4A) such as a printer, a copier, a scanner or a facsimile machine. The sloping paper feeding tray 404 is for accommodating the to-be-fed paper sheet 402. Both the automatic paper feeding roller set 406 and the paper feeding pad 410 are disposed at the bottom of the sloping paper feeding tray 404. A feeding end 412 is formed by a flange of the automatic paper feeding roller set 406 and the paper feeding pad 410, wherein the flange of the automatic paper feeding roller set 406 and the paper feeding pad 410 are adjacent to and in contact with each other. Moreover, the automatic paper feeding roller set 406 rotates clockwise around a roller shaft 416 and carries the to-be-fed paper sheet 402 to move forward.
The bearing board 407, with its one end being pivotally connected to the sloping paper feeding tray 404, is able to turn around on the sloping paper feeding tray, while the other end of the bearing board 407 supports the to-be-fed paper sheet 402. The Mylar 408, which is disposed between the sloping paper feeding tray 404 and the bearing board 407, may elastically spring the other end of the bearing board 407 so that an included angle ψ1 is created between the bearing board 407 and the sloping paper feeding tray 404.
The Mylar 408 includes a junction portion 408a, a supporting portion 408b and a bending portion 408c, wherein the supporting portion 408b connects the junction portion 408a and the bending portion 408c with the junction portion 408a being flatly adhered onto the sloping paper feeding tray 404. The supporting portion 408b, which creates another included angle with the sloping paper feeding tray 404, elastically supports the bearing board 407. The bending portion 408c forms an included angle with the supporting portion 408c, wherein the included angle may be a fixed included angle or an adjustable included angle. Furthermore, one terminal end of the bending portion 408c is embedded into a slot 413 of the sloping paper feeding tray 404. As more and more paper sheets are placed on the bearing board 407, the included angle between the bearing board 407 and the sloping paper feeding tray 404 becomes smaller while the bending portion 408c slide inwardly along the slot 413. The bearing board 407 uses the elasticity of the Mylar 408 to support the to-be-fed paper sheet 402 with the front end of to-be-fed paper 402 reaching the feeding end 412, so that the automatic paper feeding roller set 406 may carry the to-be-fed paper sheet 402 to move towards the feeding end 412.
Referring to FIG. 4B, a cross-sectional view of the structure of the automatic document feeder 400 of FIG. 4A with a paper stack being loaded therein is shown. In FIG. 4B, the paper stack 414 including a paper sheet 402a, a paper sheet 402b, a paper stack 414a and a paper sheet 402c arranged in a top-down order is loaded in a sloping paper feeding tray 404. Since the downward gravity of the paper stack 414 is larger than the gravity of the single to-be-fed paper sheet 402 in FIG. 4A and the upward elasticity of the Mylar 408 as well, the included angle between the bearing board 407 and the sloping paper feeding tray 404 is smaller than ψ1 while the bending portion 408c slides inwardly along the slot 413. Consequently, the bottom of the supporting portion 408b of the Mylar 408 may even come into contact with the sloping paper feeding tray 404, while the bending portion 408c may be completely embedded into the slot 413 with the bottom of the bearing board 407 touching one end of the junction portion 408a. Meanwhile, the front end of the paper stack 414 reaches the paper feeding pad 410 and the front end of the paper sheet 402a just reaches the feeding end 412.
After the automatic paper feeding roller set 406 has sequentially carried the paper sheet 402a, the paper sheet 402b and the paper stack 414a to move forward and to be fed into the office machine, only the paper sheet 402c will be left at the sloping paper feeding tray 404 like the case in FIG. 4A. Owing to the upward elasticity of the Mylar 408, the included angle between the bearing board 407 and the sloping paper feeding tray 404 will be expanded and become ψ1, while the bending portion 407c will slide outwardly along the slot 413 to push the paper sheet 402c upward with the front end of the paper sheet 402c reaching the feeding end 412. Consequently, the automatic paper feeding roller set 406 may carry the paper sheet 402c to move towards the feeding end 412. The step of automatic document feeding of the automatic document feeder 400 is completed here.
However, anyone who is familiar with the invention will realize that the technique of the invention is not limited thereto. For example, owing to the sloping design of the structure of the sloping paper feeding tray, after a paper sheet is loaded into the sloping paper feeding tray, the paper sheet will be disposed on the bearing board with a slope so that the front end of the paper sheet will automatically slide to the feeding end. Therefore, the upward elasticity of the elastic structure of the invention does not need to be as large as that in FIG. 1A. A smaller upward elasticity will do as long as the elasticity suffices to enable the front end of the paper sheet to reach the feeding end after the paper sheet slides into the sloping paper feeding tray due to gravity.
With the design of disposing a bearing board on a sloping paper feeding tray, the automatic document feeder disclosed above not only protects the Mylar disposed under the bearing board from being damaged but also reduces the damage rate of the Mylar, so that the lifespan of the Mylar may be lengthened and a stable operation of the automatic document feeder may be achieved.
While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.
Patent Application
20050133984
