Abstract:
A media conveying mechanism located in a media data recorder for conveying media mainly includes a driving motor to provide driving power needed. A first clutch to control the operation of a pickup roller. A second clutch to control rotation direction of an intermediate roller, a sensor to detect the conveying process of the media and control the operation of the second clutch. By deploying the two clutches, conveying quantity of the media in a unit time period can be effectively improved.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a media conveying mechanism adopted for use on media data recorders such as printers, facsimile machines, scanners and the like to convey media and particularly to a media conveying mechanism to greatly improve media conveying speed. 
     BACKGROUND OF THE INVENTION 
     Media data recorders are widely used in individual and industrial businesses such as exchange of letters and documents, performing document scanning, printing, copying or facsimile operations. There is a wide variety of media data recorders, such as ink-jets, lasers and impact printers, plotters, scanners, copiers, multi-functional peripheral (MFP), and the like. Printing quality and operation efficiency of the media data recorders have always been key development focuses in this industry. 
     The present media data recorders, such as copiers, mostly employ roller mechanisms to convey media in the operations of media feeding, scanning, printing or discharging.  FIGS. 1A and 1B  illustrate the general or conventional technique of the media conveying mechanism that is usually adopted. It mainly includes a pickup roller  110 , intermediate roller  120  and delivery roller  130 . A motor  100  provides the driving power required for roller operation. In practice, there are also belts or a plurality of auxiliary gears to couple with the main operation gears and motor  100 . The drawings show only three main operation gears. When a copier media (such as paper  200 ) is fed, the pickup roller  110  and the intermediate roller  120  rotate counterclockwise at the same time to pick up the paper  200 . Meanwhile, the delivery roller  130  rotates clockwise aiming to align the front edge of the paper  200  before it arrives at the delivery roller  130  so that the paper  200  can pass through an image processing device  140  and obtain correct image output without skewing. As shown in  FIG. 1B , after the paper  200  has been aligned, the delivery roller  130  transports the paper  200  for discharging with the aid of the rotating intermediate roller  120 . 
     The operation of the conventional mechanism set forth above requires a motor  100  to switch rotation clockwise or counterclockwise. And only when the paper  200  has been completely moved away from the delivery roller  130  can the motor  100  switch operation direction to pick up the next paper  200 . Hence two consecutive papers  200  have to be spaced from each other for a long distance. This causes unnecessary idling of the image-processing device  140  or other printing conveying modules. This is not efficient. 
     SUMMARY OF THE INVENTION 
     In view of the aforesaid disadvantages, the primary object of the invention is to provide a media conveying mechanism for use on media data recorders such as copiers, facsimile machines, multi-functional peripherals and the like to effectively improve media conveying speed. 
     The media conveying mechanism of the invention mainly includes a driving motor, first clutch, second clutch, pickup roller, intermediate roller, delivery roller and sensor. The driving motor provides driving power required by the mechanism during operation. The pickup roller is installed on the starting location of the media-conveying path of the mechanism to transport the papers. The first clutch is coupled with the driving motor and located on the media-conveying path to control the operation of the pickup roller. The intermediate roller is located on the media-conveying path to aid media transportation. The second clutch, like the first clutch, also is coupled with the driving motor to control the operation of the intermediate roller. The sensor is located on the media-conveying path to detect the paper conveying process and control the operation of the second clutch. The delivery roller is located on a distal end of the media-conveying path for discharging the media outside the mechanism. 
     During operation, first, the pickup roller catches and rolls the media into the media-conveying path. Next, the first clutch is pressed by the media to stop the operation of the pickup roller, and the intermediate roller continuously conveys the paper. When the sensor detects the front edge of the paper, the delivery roller rotates in the direction contrary to the intermediate roller so that the front edge of the paper may be aligned before arriving the delivery roller. The aligned paper is transported to leave the mechanism by the delivery roller and the intermediate roller; finally the paper is caught and discharged outside the mechanism by a discharge roller. When the rear edge of the paper departs from the first clutch, the first clutch returns to its original condition to continuously drive the pickup roller to fetch the next paper. Compared with the conventional techniques that convey the next media only after the paper has completely departed from the media mechanism, the mechanism of the invention can start conveying operation for the next paper when the rear edge of the current paper departs from the first clutch. Thus media conveying time is effectively reduced, and media-conveying speed greatly improves. 
     The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A and 1B  are schematic views of a conventional media conveying mechanism in operating condition. 
         FIG. 2  is a schematic view of the media conveying mechanism of the invention. 
         FIGS. 3 through 7  are schematic views of the media conveying mechanism of the invention in operating condition. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The media conveying mechanism according to the invention is installed in media data recorders for conveying a selected number of papers. It mainly aims to speed up media conveying speed. 
     Refer to  FIG. 2  for the basic structure of the media conveying mechanism of the invention. It has a media conveying path, along the moving direction of media  200 , there are a pickup roller  10 , an intermediate roller  20 , a delivery roller  30  and a discharge roller  80  disposed in this order. There is an auxiliary pickup roller  11  installed on a location corresponding to the pickup roller  10 , and spaced from the pickup roller  10  at a selected distance to couple with the pickup roller  10  to catch papers  200  of different thickness. There is also an auxiliary intermediate roller  21  installed on a location corresponding to the intermediate roller  20  and spaced from the intermediate roller  20  at a selected distance to couple with the intermediate roller  20  to catch papers  200  of different thickness. There is further an auxiliary delivery roller  31  installed on a location corresponding to the delivery roller  30  and spaced from the delivery roller  30  at a selected distance to couple with the delivery roller  30  to catch papers  200  of different thickness. Similarly, there is an auxiliary discharge roller  81  installed on a location corresponding to the discharge roller  80  and spaced from the discharge roller  80  at a selected distance to couple with the discharge roller  80  to catch papers  200  of different thickness. 
     The driving motor  70  provides the driving power required for the operation of the entire mechanism. It drives a first driving gear  71 , a second driving gear  72  and a third driving gear  73 . While three driving gears are indicated in the drawings, it is by no means the limit of the driving gear number that can be used to transmit the driving power to other elements. The first clutch is coupled to the driving motor  70  via the gears and is located on the media conveying path to control the operation of the pickup roller  10 . The first clutch consists of a first clutch lever  40 , a first clutch gear  41  and a first clutch idle gear  42 . The first clutch lever  40  is installed in the media data recorder in a swinging manner and may be extended outside the media-conveying path. An elastic element (such as a torsion spring) may be installed on the juncture of the first clutch lever  40  and the media data recorder to allow the media  200  to press the first clutch lever  40  to generate a swinging motion. The first clutch gear  41  is located on one side of the first clutch lever  40 . The first clutch idle gear  42  is coupled with the first clutch gear and drives the pickup roller  10  through a belt  43 . Of course direct coupling may be adopted to transmit the driving power without using the belt  43  as shown in the drawings. The second clutch consists of a second clutch lever  50  installed in the media data recorder in a swinging manner and a first idle gear  51  coupled with the driving motor  70 . The second clutch lever  50  and the first idle gear  51  have a friction force formed there between. When the first idle gear  51  changes rotating direction, the second clutch lever  50  rotates accordingly. There is a second clutch right gear  54  installed on one end of the second clutch lever  50  to couple with the first idle gear  51 . A second clutch left gear  52  is installed on other end of the second clutch lever  50  to couple with the first idle gear  51 . There is further a sensor  60  located on a distal end of the media conveying path to control the operation of the second clutch. 
       FIG. 2  and the construction set forth generally illustrate the mechanism of the invention. The movements and operational relationship of various elements are elaborated as follows: 
     Referring to  FIG. 3 , first, the driving motor  70  provides driving power which is transferred through the first idle gear  51 , first clutch gear  41  and first clutch idle gear  42  to pick up the paper  200  by coupling with the auxiliary pickup roller  11  until the paper  200  is in contact the first clutch lever  40 . Referring to  FIG. 4 , the front edge of the paper  200  touches the first clutch lever  40  and continuously moves forwards and presses the first clutch lever  40  to turn a selected angle. Thereby, the first clutch gear  41  is moved away from the first clutch idle gear  42  to stop the pickup roller  10  from fetching the papers  200 . Meanwhile, the forward movement of the papers  200  is taken over by the intermediate roller  20  and the auxiliary intermediate roller  21 . The driving power for the operation of the intermediate roller  20  is transferred from the driving motor  70  through the first idle gear  51 , second clutch left gear  52  and second idle gear  53 . The rotation direction of the intermediate roller  20  is the same as the rotation direction of the delivery roller  30 . Referring to  FIG. 5 , when the front edge of the media  200  is detected by the sensor  60 , an electronic signal is transmitted to control the driving motor  70  to change rotation direction and move the second clutch lever  50  to turn a selected angle. After the second clutch lever  50  has been turned, the second clutch left gear  52  is disengaged with the second idle gear, and the second clutch right gear  54  is directly coupled with the intermediate roller  20  to continuously move the media  200  forwards. As the rotation direction of the intermediate roller  20  is contrary to the deliver roller  30 , the front edge of the paper  200  will be aligned in front of the delivery roller  30 . 
     Referring to  FIG. 6 , after the front edge of the paper  200  has been aligned, the rotation direction of the driving motor  70  changes again, and the paper  200  is moved away by the delivery roller  30  and the discharge roller  80 . Data on the paper  200  may be read by an image-capturing device  90 . Other operations related to the paper  200  may also be executed through other selected devices. Referring to  FIG. 7 , when the rear edge of the paper  200  departs from the first clutch lever  40 , the first clutch lever  40  returns to its original position. Further, the first clutch gear  41  drops to engage with the first clutch idle gear  42  to transfer the driving power of the driving motor  70  and drive the pickup roller  10  to pick up the next paper  200 . 
     By means of the construction set forth above, the media conveying mechanism of the invention can provide the following advantages:
         1. High speed media feeding operation: Compared with the conventional techniques that have to move the paper away completely from the media conveying mechanism before picking up another paper, the invention can start paper feeding operation for the next paper when the rear edge of the current paper leaves the first clutch lever. Thus unit paper conveying time can be greatly reduced to achieve high-speed paper feeding operation.   2. Simple construction: The media conveying mechanism of the invention has a simple structure which employs simple clutch mechanisms. Fabrication and assembly can be accomplished in a short time, to facilitate production. The costs are also lower. Thus competitiveness of the product can be enhanced.       

     While the preferred embodiments of the invention have been set forth for the purpose of disclosure, modifications of the disclosed embodiments of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments, which do not depart from the spirit and scope of the invention.