Abstract:
A carrier device for a contact image sense optical scanner. The carrier device incorporates a pair of magnets with identical poles facing each other or a fluid filled sealed chamber for exerting an equal pressure on a scanning module within the scanner and maintaining close contact with a document platform throughout a scanning operation.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of Invention  
           [0002]    The present invention relates to a scanner carrier. More particularly, the present invention relates to a carrier structure inside the scanning module of a contact image sensor (CIS) type optical scanner.  
           [0003]    2. Description of Related Art  
           [0004]    Contact image sensor (CIS) is a type of linear scanner commonly used for scanning an image or a document. The image or document is captured in an electronic format for ease of storage, display, processing and transmission. Due to a modular design, the CIS is easy to assemble, light, compact and costs less to produce.  
           [0005]    [0005]FIG. 1 a  is a front view of the scanning module of a conventional contact image sensor and FIG. 1 b  is a cross-sectional view of the scanning module. As shown in FIGS. 1 a  and  1   b , a conventional contact image sensor (CIS)  100  consists of a linear light source  104 , a self-focus lens array  101  and a sensing array  102  over a substrate board  103 . The light source  104 , the self-focus lens array  101 , the sensing array and the substrate board  103  are mounted on an aluminum frame  105 . In a scanning operation, the self-focus lens array  101  reflects light coming from the original document and forms an image on the sensing array  102 . The sensing array  102  converts a line of color or gray scale light into electronic signals. Throughout the scanning session, the scanning surface  110  of the scanning module  100  in constant contact with a document platform  200  via a buffer plate  300  is pulled forward or backward by an electric motor.  
           [0006]    The convention CIS scanning module  100  uses the buffer plate  300  for close contact between the scanning surface  110  and the document platform  200 . In general, an external locking mechanism or supporting element is present to ensure a close contact between the scanning module  100  and the document platform  200  during scanning movement. However, the locking mechanism or supporting element is a mechanical prop that only provides support in a few fixed locations on the scanning module  100 . Hence, close contact everywhere with the document platform cannot be ensured.  
         SUMMARY OF THE INVENTION  
         [0007]    Accordingly, one object of the present invention is to provide a scanner carrier that provides a high-quality scanning operation. The scan carrier utilizes the repulsive forces brought about by the identical pole pieces of a pair of magnet or the pressure produced by liquid or gas to ensure a close contact between the scanning module of a contact image sense scanning module and a document platform.  
           [0008]    To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a carrier device for an optical scanner. The optical scanner at least includes a document platform. The carrier device comprises a base, a contact image sense (CIS) scanning module, a first magnet, a second magnet and a plurality of buffer plates. The base is shaped like an open trough. The first magnet is at the bottom of the open trough. The scanning module enclosed inside the open trough has a scanning surface. The scanning surface heads towards the exterior of the open trough and faces the document platform. The second magnet is attached to the exterior surface at the bottom of the scanning module facing the interior of the open trough. The second magnet has an area roughly equal to the bottom surface of the scanning module. The second magnet and the first magnet are roughly of equal size. Furthermore, the first and the second magnet are arranged to have identical polarity facing each other so that the magnets together set up a repulsive force. Since the second magnet is attached to the exterior surface at the bottom of the scanning module, the scanning module is pressured by a magnetic repulsion with the first magnet. The buffer plates are attached to the inner edge of the scanning surface in contact with the document platform.  
           [0009]    The invention also provides a second carrier device for an optical scanner. The optical scanner at least includes a document platform. The carrier device comprises a base, a contact image sense (CIS) scanning module, a seal ring and a plurality of buffer plates. The base is shaped like an open trough. The scanning module has a scanning surface that heads towards the exterior of the open trough and faces the document platform. There is a gap between the four walls of the open trough and the scanning module. The seal ring is inserted into the gap such that the space enclosed by the four sidewalls of the open trough and the exterior surface near the bottom of the scanning module are sealed. The sealed space is filled with a fluid. The buffer plates are attached to the inner edge of the scanning surface in contact with the document platform. The fluid filling the sealed space may be a liquid or a gas.  
           [0010]    One major aspect of this invention is the utilization of magnetic repulsion between a pair of identical magnet to press the CIS scanning module tightly against the document platform so that a better scanning quality is obtained.  
           [0011]    A second aspect of this invention is the utilization of fluid pressure acting through a sealed chamber to press the CIS scanning module tightly and uniformly against the document platform so that a better scanning quality is obtained.  
           [0012]    It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings,  
         [0014]    [0014]FIG. 1 a  is a front view of the scanning module of a conventional contact image sensor;  
         [0015]    [0015]FIG. 1 b  is a cross-sectional view of the scanning module of the contact image sensor shown in FIG. 1 a;    
         [0016]    [0016]FIG. 2 a  is a perspective view showing all the components of a carrier device of a CIS scanning module according to a first embodiment of this invention;  
         [0017]    [0017]FIG. 2 b  is a cross-sectional view of the assembled carried device of the CIS scanning module according to the first embodiment of this invention; and  
         [0018]    [0018]FIG. 3 is a cross-sectional view of an assembled carrier device of a CIS scanning module according to a second embodiment of this invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]    Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.  
         [0020]    [0020]FIG. 2 a  is a perspective view showing all the components of a carrier device of a CIS scanning module according to a first embodiment of this invention. FIG. 2 b  is a cross-sectional view of the assembled carried device of the CIS scanning module according to the first embodiment of this invention. As shown in FIGS. 2 a  and  2   b , the carrier device of the CIS scanning module includes a carrier base  1400 , a first magnet  1510 , a CIS scanning module  1100  and a plurality of buffer plates  1300 . The carrier base  1400  has an open trough shape. The first magnet  1510  is attached to the interior surface at the bottom of the carrier base  1400 . The second magnet  1500  is attached to the exterior surface at the bottom of the CIS scanning module  1100  facing the first magnet  1510 . The polarity of the first and the second magnet are arranged to have identical pole types and are facing each other. Hence, the repulsive force caused by the repulsion between the first and the second magnet pushes the scanning module  1100  up. The trough opening of the base carrier  1400  is only slightly greater than the external dimension of the scanning module  1100  so that movement of the scanning module  1100  is limited to vertical up/down motion. The buffer plates  1300  are attached to the interior edge of the scanning surface  1110  above the CIS scanning module  1100 . Through the buffer plates  1300 , the CIS scanning module  1100  is pressed tightly against a document platform  1200 .  
         [0021]    Since the repulsive forces resulting from the magnetic repulsion act uniformly across the bottom surface of the scanning module  1100 , the CIS scanning module  1100  is able to press against the document platform tightly.  
         [0022]    [0022]FIG. 3 is a cross-sectional view of an assembled carrier device of a CIS scanning module according to a second embodiment of this invention. As shown in FIG. 3, the contact image sense (CIS) scanning module  1100  is enclosed within the trough interior of a carrier base  1400 . A seal ring  1700  encloses the space between the four vertical sidewalls of the scanning module  1100  and the four interior sidewalls of the carrier base  1400 , thereby forming a sealed chamber. A fluid  1600  is injected to fill the sealed chamber. The fluid  1600  can be a liquid or a pressurized gas, for example. Weight of the scanning module  1100  is supported by fluid pressure inside the sealed chamber. Through a pipeline  1810 , the sealed chamber within the base carrier  1400  is connected to a pump  1800  so that the pump  1800  is able to regulate fluid pressure within the sealed chamber. The buffer plates  1300  are attached to the interior edge of a scanning surface  1110  above the CIS scanning module  1100 . Through the buffer plates  1300 , the CIS scanning module  1100  is pressed tightly against a document platform  1200 .  
         [0023]    Since the fluid  1600  is able to provide exert equal pressure on the bottom surface of the CIS scanning module  1100 , the scanning module  1100  is able to press against the document platform tightly.  
         [0024]    In conclusion, major advantages of this invention include:  
         [0025]    1. Magnetic repulsion between a pair of identical magnets is utilized to provide the necessary pressure for pressing the CIS scanning module tightly against the document platform and obtain a better scanning quality.  
         [0026]    2. Alternatively, fluid pressure acting through a sealed chamber is utilized to provide the necessary pressure for pressing the CIS scanning module tightly against the document platform and obtain a better scanning quality  
         [0027]    It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.