Abstract:
A scanning apparatus having an adjusting means is provided to allow the optical scanning module against the platen. The adjusting means is assembled with the carriage that carries the optical scanning module. The adjusting means at least comprises a roller and a rotated portion, wherein the roller tightly contacts the rotated portion. When the carriage is moving (during a scanning operation), the roller is rotating and friction (between the roller and the rotating assembly) causes the rotated portion to turn until contacting with the bottom surface of the optical scanning module, thereby allowing the optical scanning module against the platen.

Description:
[0001]     This application claims the benefit of Taiwan application Serial No. 92131002, filed Nov. 5, 2003, the subject matter of which is incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The invention relates in general to a scanning apparatus having an adjusting means for adjusting the position of the optical scanning module, and more particularly to the adjusting means for lifting the optical scanning module up and against the platen during the scanning operation.  
         [0004]     2. Description of the Related Art  
         [0005]     In the Age of high technology, scanner has been required in the modern life due to its great functions of scanning the original drafts, such as the pictures, the photos and the documents, and then transforming and saving the image as the digital files. It is a very convenient way for the users to keep or find the original drafts. The structure and the principle of the scanner are described below.  
         [0006]     A conventional optical scanner has a transparent platen for placing an original to be scanned document. A moving carriage assembly and the drive mechanisms are positioned underneath the transparent platen. The moving carriage assembly, including an optical scanning module supported by a carriage, contains the optical and electronic or reflective components, and moves across the complete length of the document during scanning. The components commonly used for the carriage assembly are the light source, the reflector, the lens and the photo-electronic sensing device. Drive mechanisms for moving the carriage assembly are varied. During scanning, the light emitted from the light source is reflected by the original to be scanned document, and then further reflected by the lens and focused on the photo-electronic sensing device by the lens. Afterward, the light signal received by the photo-electronic sensing device is converted into electronic signals, and then produce machine-readable data, which is representative of the image of the original document. The photo-electronic sensing device can be any device capable of converting the light signal into the electric signal, such as charged coupled device (CCD) or contact image device (CIS).  
         [0007]     During scanning, the carriage assembly is required to move against the transparent platen, particularly the carriage assembly using contact image device (CIS) (which has a short scene depth of about 0.3 mm) as the photo-electronic sensing device.  FIG. 1  is an explosive view schematically showing a conventional structure of the contact image device (CIS) module and the carriage apparatus. The transparent platen  10  is used for placing an original to be scanned document. Under the transparent platen  10 , the optical scanning module  12  is loaded in the carriage  14  which is positioned on a shaft (not shown) by a connecting means  16 , and the drive mechanism (not shown) drives the carriage  14  to move along the scanning direction on the shaft. Also, a spring  18  is interposed between the optical scanning module  12  and the carriage  14 . The spring  18  provides an upward elastic force to lift the optical scanning module  12  up until contacting the bottom surface of the transparent platen  10 , thereby making the optical scanning module  12  move against the transparent platen  10  during a scanning operation.  
         [0008]     As be known, the degree of fidelity with which the information presented by the to be scanned document is recorded depends on the accuracy with which the moving carriage assembly is guided during the scanning operation. The reproduction is liable to be impaired even by small changes in either the direction of relative scanning movement or the spacing between the document and the optical scanning module  12  from one moment to another in the scanning operation. The conventional design with a spring  18  between the scanning apparatus and the carriage, however, is difficult to keep the optical scanning module  12  in balance, particularly in a scanning movement. It is also difficult to precisely and firmly locate the spring  18  at the center of the carriage  14 . In practice it would be desirable to design not only an easy to be assembled but also a more reliable and stable structure to lift the scanning module up for contacting with the platen, thereby obtaining an optimal scanning image result with a high standard of accuracy.  
       SUMMARY OF THE INVENTION  
       [0009]     It is therefore an object of the invention to provide a scanning apparatus having an adjusting mean for adjusting the position of the optical scanning module. In the invention, one of two objects in contact rotates simultaneously makes the other object rotates due to friction between two objects. Therefore, an upward force directly or indirectly acts on the optical scanning module and lifts it up and against the platen.  
         [0010]     The invention achieves the objects by providing a scanning apparatus having an adjusting mean for adjusting the position of the optical scanning module. The scanning apparatus comprises a platen for placing a to-be-scanned document; an optical scanning module disposed under the platen for scanning and acquiring an scanned image of the to-be-scanned document; and a carriage for carrying the optical scanning module to move backward and forward in the scanning apparatus. The carriage has an adjusting means, comprising a roller and a rotated portion, to change the position of the optical scanning module.  
         [0011]     When the roller is rotating, friction between the rotated portion and the roller makes the rotated portion rotate until touching the optical scanning module, thereby lifting the optical scanning module upward and against the platen during a scanning operation.  
         [0012]     According to the object of the invention, a first contacting manner of the adjusting means is provided. The rotated portion comprises: a shaft, penetrating a through hole of the roller; a swim, connected to one end of the shaft and firmly contacting with the first surface of the roller; a secured body, connected to the other end of the shaft; and a spring, received in a hole of the roller, and two ends of the spring respectively connected to the secured body and the roller. The elastic force of the spring pushes the secured body away from the roller so as to make the swim firmly contact with the first surface of the roller.  
         [0013]     According to the object of the invention, a second contacting manner of the adjusting means is provided. The rotated portion comprises: a shaft, penetrating through a first hole of the roller; a swim, connected to one end of the shaft; a secured body, connected to the other end of the shaft; and a spring, received in a second hole of the roller, and two ends of the spring respectively connected to the swim and the secured body. An inward elastic force of the spring pulls the secured body and the swim toward the roller thereby forcing the swim and the secured body to firmly contact with the first surface and the second surface of the rollers, respectively.  
         [0014]     According to the object of the invention, a third contacting manner of the adjusting means is provided. The rotated portion comprises: a shaft, penetrating a through hole of the roller; a swim, connected to one end of the shaft, and disposed on an opposite side of the first surface of the roller; a secured body, connected to the other end of the shaft; and a spring, received in a hole of the roller, and two ends of the spring respectively connected to the swim and the roller. The elastic force of the spring pushes the swim away from the roller so as to make the secured body firmly contact with the second surface of the roller.  
         [0015]     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  
       [0016]      FIG. 1  (prior art) is an explosive view schematically showing a conventional structure of the contact image device (CIS) module and the carriage apparatus;  
         [0017]      FIG. 2  schematically illustrates a side view of the optical scanning module, the carriage and the adjusting means in accordance with the preferred embodiment of the invention;  
         [0018]      FIG. 3  is a partial enlarged sectional view of an adjusting means shown in  FIG. 2 ;  
         [0019]      FIG. 4  schematically illustrates the adjusting means of  FIG. 2  from a bottom view angle;  
         [0020]      FIG. 5  is a cross-sectional diagrammatic side view of the adjusting means taken along the section line A-A of  FIG. 3 ;  
         [0021]      FIG. 6A  illustrates the first contacting manner of the adjusting means according to the invention;  
         [0022]      FIG. 6B  illustrates the second contacting manner of the adjusting means according to the invention; and  
         [0023]      FIG. 6C  illustrates the third contacting manner of the adjusting means according to the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0024]     In the present invention, an adjusting means assembled with the carriage is mechanically constructed by using two objects in contact. When the first object rotates, the second object could be directly or indirectly rotated to provide an external force on the optical scanning module, thereby lifting the optical scanning module upwardly and against the transparent platen.  
         [0025]     Additionally, the drawings used for illustrating the embodiments of the invention only show the major characteristic parts in order to avoid obscuring the invention. Accordingly, the specification and the drawing are to be regard as an illustrative sense rather than a restrictive sense.  
         [0026]      FIG. 2  schematically illustrates a side view of the optical scanning module, the carriage and the adjusting means in accordance with the preferred embodiment of the invention. The optical scanning module  22  is loaded in the carriage  24  which is mounted on a shaft (not shown) by a connecting means  16  and moved by the drive mechanism (not shown) along the scanning direction on the shaft. Also, there are two adjusting means  28   a  and  28   b  assembled on the both sides of the bottom surface of the carriage  24  for lifting the optical scanning module  22  up.  
         [0027]     Although two adjusting means are illustrated in the preferred embodiment, it is not for the purpose of limiting the present invention. Noted that the object of lifting the optical scanning module can still be achieved even only one adjusting means is provided, for example, at or close to the center of the carriage.  
         [0028]      FIG. 3  is a partial enlarged sectional view of an adjusting means shown in  FIG. 2 . As appears from  FIG. 3 , the carriage  24  is mounted on the shaft  32  through the connecting means  26 , and moved on the shaft  32  along the scanning direction. The adjusting means at least comprises a roller  34  and a swim  36 , which the swim  36  is able to press the roller  36  firmly after assembling. Also, the roller  34  touches the bottom surface of the scanner&#39;s housing, so that the roller  34  will simultaneously rotates with the movement of the carriage  24 . When the optical scanning module  22  (loaded in the carriage  24 ) is moving along the scanning direction (as indicated by arrow F in  FIG. 2 ), the rotating roller  34  will bring the firmly attached swim  36  up by doing the clockwise rotation simultaneously. The swim  36  is going to rotate until touching the bottom surface of the optical scanning module  22 ; consequently, the upward swim  36  forces the optical scanning module  22  up to contact the transparent platen  31 .  
         [0029]     After actual scanning operation, the carriage  24  is moved backward (opposite to the direction indicated by arrow F) to return to its original position, and the swim  36  is consequently doing the counterclockwise rotation. When the bottom surface of the optical scanning module  22  is not being touched by the swim  36 , the external force vanishes and the optical scanning module  22  returns to its original position. Moreover, a fixing pin  37  could be optically constructed to maintain the swim  36  at a resting position. In practice the fixing pin  37  could be formed on the bottom housing of the carriage  24 .  
         [0030]      FIG. 4  schematically illustrates the adjusting means of  FIG. 2  from a bottom view angle. The optical scanning module  22  is loaded in the carriage  24 . In practice an opening of the carriage  24  would be optimal formed to expose a partial of the bottom surface  22   a  of the optical scanning module  22  for being touched by the swim  36 .  
         [0031]      FIG. 5  is a cross-sectional diagrammatic side view of the adjusting means taken along the section line A-A of  FIG. 3 . The roller  34  has a first surface  34   a  and a second surface  34   b . The swim  36  tightly presses on the first surface  34   a  of the roller  34 . The adjusting means further has a shaft  42  penetrating the roller  34 , and one end of the shaft  34  is connected to the swim  36 . In practice the shaft  42  and the swim  36  could be integrated as a whole. When the roller  34  rotates, friction between the first surface  34   a  of the roller  34  and the swim  36  in contact resists the relative motion of the roller  34  and swim  36  thereby simultaneously bringing the swim  36  upward with the rotating roller  34  to lift the optical scanning module  22 .  
         [0032]     In the embodiment, the other end of the shaft  42  is connected to a secured body  43  that tightly presses on the second surface  34   b  of the roller  34 . Therefore, friction between the second surface  34   b  of the roller  34  and the secured body  43  also makes the secured body  43 , the shaft  42  and the swim  36  rotate with the rotating roller  34 .  
         [0033]     Moreover, a spring  46  could be preferably added between the roller  34  and the secured body  43 , for preventing the secured body  43  away from the roller  34  and enhancing friction between thereof. Alternatively, the spring  46  could be compressed between the roller  34  and the secured body  43  to push the secured body  43  outwardly, thereby making the swim  36  tightly press on the first surface  34   a  of the roller  34 .  
         [0034]     In this embodiment, it is very beneficial for the rotated swim  36  of the adjusting means to make the swim  36  and the secured body  43  tightly contact with the first surface  34   a  and the second surface  34   b  of the roller  34 , respectively. When the roller  34  is rotating, friction existing on two sides of the roller  34  simultaneously brings the swim  36  into a rotating situation until the swim  36  touches the bottom surface  22   a  of the optical scanning module  22 . During a scanning operation, the rollers keeps rotating with the movement of the carriage  24 , so that the swim  36  continuously push the optical scanning module  22  upwardly and against the transparent platen  31  to acquire the optical image of the to be scanned document.  
         [0035]     Although friction existing at two different places (i.e. between the roller  34  and the swim  36 , and between the roller  34  and the secured body  43 ) are constructed in the preferred embodiment (as illustrated in  FIG. 3 ,  FIG. 4  and  FIG. 5 ), only one contacting friction would be applicable in practice to accomplish the purpose of lifting the optical scanning module  22 . There are three tightly contacting manners illustrated below.  
         [0036]      FIG. 6A  illustrates the first contacting manner of the adjusting means according to the invention. The shaft  62  penetrates through the roller  64  in the center, and one end of the shaft  62  is connected to the swim  66  as a whole. The roller  64  has a first surface  64   a  and a second surface  64   b . The swim  66  firmly presses on the first surface  64   a  of the roller  64 . When the roller  64  is rotating, friction between the first surface  64   a  of the roller  64  and the swim  66  makes the swim  36  rotate, thereby lifting the optical scanning module  22  up and against the transparent platen  31 . Also, it would be practically to add a securing means on the other end of the shaft  62 , for example, an E-ring, for the purpose of preventing the shaft  62  as well as the swim  66  apart from the roller  64 .  
         [0037]      FIG. 6B  illustrates the second contacting manner of the adjusting means according to the invention. The secured body  63  and the swim  66  firmly contact with the second surface  64   b  and the first surface  64   a  of the rollers  64 , respectively. When the roller  64  rotates, not only the friction existing on the right side of the roller  64  makes the swim  66  rotate but also the friction existing on the left side of the roller  64  brings the secured body  63  into a rotating movement. The preferred embodiment ( FIG. 3 ,  FIG. 4  and  FIG. 5 ) is one illustration of the second contacting manners of the adjusting means. Also, there is a hole through the roller  64  for receiving the spring  46 , and two ends of the spring  46  are connected to the secured body  63  and the swim  66 . An inward elastic force of the spring  46  pulls the secured body  63  and the swim  66  toward the roller  64  so that the secured body  63  and the swim  66  are forced to firmly contact with the second surface  64   b  and the first surface  64   a  of the rollers  64 , respectively. Moreover, at least one of the secured body  63  and the swim  66  is able to slide on the shaft  62 , and a round hole thereof is preferably constructed for receiving a non-round shaft  62 .  
         [0038]      FIG. 6C  illustrates the third contacting manner of the adjusting means according to the invention. The secured body  63  firmly presses on the second surface  64   b  of the roller  64  but the swim  66  doesn&#39;t entirely contact with the first surface  64   a  of the roller  64 . The hole in the roller  64  for receiving the spring  46  is constructed close to the swim  66 . An elastic force of the spring  46  pushes the swim  66  away from the roller  64  so as to make the secured body  64  firmly attach on the second surface  64   b  of the roller  64 . When the roller  64  rotates, friction between the roller  64  and the secured body  63  causes the secured body  63  to turn, and simultaneously brings the swim  66  into a rotating situation via the shaft  62 .  
         [0039]     According to the aforementioned description, one of two objects in contact rotates simultaneously makes the other rotates, due to friction between two objects. When the roller (the first object) rotates, the swim (the second object, directly contacting with the first object) could be directly rotated, or indirectly brought into a rotating movement (via the secured body contacting with the first object). Additionally, roughing the surfaces in contact could enhance friction between the first and the second objects.  
         [0040]     Compared to the conventional design that installs a spring between the carriage and the optical scanning module, it is easy for the adjusting means disclosed herein to assemble with the carriage and to keep the optical scanning module in balance. Also, the mechanical construction of the adjusting means according to the invention has a long useful life.  
         [0041]     While the invention has been described by way of examples and in terms of the preferred embodiments, 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.