BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a paper feeding device, and more particularly to a paper feeding device having paper blocking unit applied in an office business machine.
2. The Related Art
Recent business machines, such as a scanner, a printer, a copier, etc., are broadly required in the office operation. The business machine has a function of image disposing. Take a conventional scanner as an example, an image disposing system of the scanner includes a glass plate, an optical system arranged under the glass plate for reading the image of the document placed on the glass plate. As a result of the application of the ADF (automatic document feeder), a stack of documents are place in a document tray of the ADF, then the documents are fed into the scanner one by one and placed on the glass plate by a paper feeding device of the ADF, at last, the optical system reads the image of the document.
In the conventional scanner, the paper feeding device further comprises a paper blocking unit, which is used to make sure that the document is placed in a proper position before being picked by the paper feeding device, thereby, the document is picked by a picking roller of the paper feeding device.
Please refer to FIGS. 1-2, a conventional paper feeding device having paper blocking unit 1′ includes a conveying roller 10′, a picking roller 20′, a blocking unit 30′ and a blocking arm 40′. The conveying roller 10′ and the picking roller 20′ are parallel to each other and located in a roller frame 50′, the blocking unit 30′ sleeves on the shaft of the picking roller 20′. The blocking arm 40′ is located on the roller frame 50′. Before the document being picked, a blocking projection 41′ of the blocking arm 40′ leans against a stopping projection 31′ of the blocking unit 30′, the documents 2′ are stopped outside, the picking roller 10′ keeps a certain distance from the documents 2′. Then referring to FIG. 2, when the document 2′ is to be picked, the roller frame 50′ drives the picking roller 10′ to move downwards, the blocking arm 40′ rotates and the blocking projection 41′ impels the stopping projection 31′ of the blocking unit 30′ to move upwards, as a result, the blocking arm 40′ loses the cooperation with the blocking unit 30′, then the documents 2′ are not stopped by the blocking arm 40′, at the same time, the picking roller 10′ contacts with the documents 2′ and the document 2s′ are fed into the scanner one by one via the paper feeding device 1′.
As described above, the blocking projection 41′ impels the stopping projection 31′ of the blocking unit 30′ to move upwards, thereby, the blocking arm 40′ loses the cooperation with the blocking unit 30′, then the documents 2′ are not stopped by the blocking arm 40′ and fed into the scanner one by one. However, the cooperation between the blocking arm 40′ and the blocking unit 30′ is liable to be lost, then the blocking projection 41′ isn't able to impel the stopping projection 31′ to move, consequently, the document 2′ isn't able to be fed into the paper feeding device 1′, the paper feeding device 1′ can not work smoothly.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a paper feeding device, comprising a cover, a pickup roller assembly and at least one paper blocking unit. The retaining portions are mounted on an inner surface of the cover. The pickup roller assembly picks up and then transfers papers into the paper feeding device. The paper blocking unit is placed beside the pickup roller assembly, having a paper blocking element and a projection mounted on the pickup roller assembly. The paper blocking element includes a connecting portion, the connecting portion has a positioning pillar rotatablely connected to the retaining portion of the cover, the connecting portion extends downwards to form a stopping portion, the stopping portion extends downwards to form a paper blocking arm, the paper blocking arm defines an opening communicating one side of the paper blocking arm near the pickup roller assembly. The projection can stops at the stopping portion of the paper blocking arm and passes through the opening of the paper blocking arm.
As described above, the paper feeding device stops the documents by the cooperation between the paper blocking element and the projection, when to feed documents, the projection passes through the opening of the blocking element to allow the document to be fed in, so the cooperation is easy, the paper feeding device works successfully.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be apparent to those skilled in the art by reading the following description of a preferred embodiment thereof, with reference to the attached drawings, in which:
FIGS. 1-2 show a conventional paper feeding device;
FIG. 3 is an exploded perspective view of a paper feeding device having paper blocking unit of the present invention;
FIG. 4 is a partial enlarged view of the encircled portion labeled IV shown in FIG. 3;
FIG. 5 is a perspective view of a pickup roller assembly;
FIG. 6 is a perspective view of a paper blocking element shown in FIG. 3; and
FIGS. 7-9 are side cross-sectional views for describing operations of the paper feeding device of the present invention.
Please refer to FIG. 3, the paper feeding device of the present invention includes a cover 10, a pickup roller assembly 20, a base 40 and a paper blocking unit 30.
Then please refer to FIG. 4 in combination with FIG. 3, a pair of plate-shaped retaining portion 11 projecting from the inner surface of the cover 10 and are parallel to each other, a restricting projection 12 is formed therebetween, a retaining hole 111 is opened in the retaining portion 11. Below the retaining portion 11, a pair of connecting portions 13 is mounted on the inner surface of the cover 10, and a receiving space 14 is formed therebetween.
Referring to FIG. 5, the pickup roller assembly 20 includes a roller frame 21, a belt 22, a picking roller 23 and a conveying roller 24. The roller frame 21 has a left side wall 211 and a right side wall 212, an active shaft 214 and an idle shaft 213 are parallel located between the left side wall 211 and the right side wall 212, a conveying roller 24 is mounted around the active shaft 214 and a picking roller 23 is mounted around the idle shaft 213. A belt 22 is sleeved on both the conveying roller 24 and the picking roller 23, and impels the conveying roller 24 and the picking roller 23 to press against the roller frame 21.
Please refer to FIG. 3 and FIG. 6, the paper blocking unit 30 includes a paper blocking element 31 and a projection 32. The paper blocking element 31 has a connecting portion 311, two opposite sides of the connecting portion 311 project to form a positioning pillar 312 respectively. A front end of the connecting portion 311 extends upward to form a restricting arm 313, the restricting arm 313 leans against the restricting projection 12 of the cover 10. The back end of the connecting portion 311 extends downwards and forms a stopping portion 315, the stopping portion 315 further extends downwards to form a paper blocking arm 314, the lower portion of the paper blocking arm 314 defines an opening 316 communicating the bottom and the right side of the paper blocking arm 314. The projection 32 is mounted on the left side wall 211 of the pickup roller assembly 20.
Please refer to FIGS. 3-6, the assemblage of the paper feeding device 1 of the present invention is described in detail hereinafter. Firstly, the belt 22 is sleeved on both the picking roller 23 and the conveying roller 24, the active shaft 214 and the idle shaft 213 are located in the roller frame 21 between the left side wall 211 and the right side wall 212, the pickup roller assembly 20 is assembled. Then the active shaft 214 is rotatablely connected to the connecting portion 13 of the cover 10 and the pickup roller assembly 20 is received in the receiving space 14 therein. Secondly, the paper blocking unit 30 is placed beside the pickup roller assembly 20, in this embodiment, the paper blocking unit 30 is placed at the left side of the pickup roller assembly 20, the positioning pillar 312 of the paper blocking element 31 is rotatablely connected to the retaining hole 111 of the cover 10, the projection 32 stops at the stopping portion 315 of the paper blocking element 31. Lastly, the cover 10 covers on the base 40, then the paper feeding device 1 of the present invention is assembled.
As shown in FIG. 7, when the paper feeding device 1 is in natural state, the picking roller 23 keeps a certain distance from the document 2, the documents 2 are stopped outside by the paper blocking arm 314, the projection 32 stops at the stopping portion 315 of the paper blocking element 31, the restricting arm 313 is stopped at the restricting projection 12.
Please refer to FIGS. 8-9, when the paper feeding device 1 picks up the document 2, a motor (not shown) drives the active shaft 214 to rotate clockwise, so the conveying roller 24 mounted on the active shaft 214 rotates, a friction created between the conveying roller 24 and the belt 22 drives the belt 22 to move along with the conveying roller 24, then a friction created between the belt 22 and the picking roller 23 drives the picking roller 23 to rotate clockwise. As the picking roller 23 and the conveying roller 24 both press against the roller frame 21, when the picking roller 23 and the conveying roller 24 rotate clockwise, a friction created between them and the roller frame 21 drives the pickup roller assembly 20 to rotate clockwise around the active shaft 214, then the picking roller 23 contacts with the document 2. Meanwhile, as the pickup roller assembly 20 moves downwards, the projection 32 mounted on the left side wall 211 of the roller frame 21 also moves downwards and passes through the opening 316 of the paper blocking element 31, so the projection 32 loses the cooperation with the stopping portion 315 of the paper blocking arm 314, the blocking arm 314 rotates clockwise around the positioning pillar 312 and is no longer stop the documents 2. Then as the belt 22 contacts with the document 2 and rotates clockwise, the friction created therebetween picked the document 2 into the paper feeding device 1.
On the contrary, when the paper feeding device 1 stops to pick documents 2, the motor (not shown) instantly rotates reversely and therefore drives the active shaft 214 to rotate anti-clockwise, then the conveying roller 24 and the picking roller 23 both rotate anti-clockwise. As the picking roller 23 and the conveying roller 24 both press against the roller frame 21, then a friction created between them and the roller frame 21 drives the pickup roller assembly 20 to rotate anti-clockwise around the active shaft 214 and move upwards, so the picking roller 23 departs from the documents 2, the paper blocking arm 314 rotates anti-clockwise around the positioning pillar 312 under its own weight, meanwhile, the projection 32 mounted on the roller frame 21 passes through the opening 316 (shown in FIG. 6) of the paper blocking arm 314 and stops at the stopping portion 315, the restricting arm 313 stops at the restricting projection 12 of the roller frame 21, then the picking roller 23 and the conveying roller 24 stop to rotate, as shown in FIG. 8, the paper feeding device 1 is in natural state, the documents 2 are stopped outside by the paper blocking arm 314.
As described above, the paper feeding device 1 stops the documents 2 by the cooperation between the paper blocking element 31 and the projection 32, when to feed documents 2, the projection 32 passes through the opening 316 of the blocking element 31 to allow the document 2 to be fed in, so the cooperation is easy, the paper feeding device 1 works smoothly.
The foregoing description of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. Such modifications and variations that may be apparent to those skilled in the art are intended to be included within the scope of this invention as defined by the accompanying claims.
Patent Application
20080197560
