Patent Publication Number: US-2006017987-A1

Title: Scan device capable of detecting an open/close state of a cover

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates to a scan device capable of detecting an open/close state of a cover, and more particularly to a scan device for detecting an open/close state of a cover by sensing ambient light.  
      2. Description of the Related Art  
      A scan device applied to current copiers, scanners, multi-function peripherals and the like, has to preheat a lamp before a scanning procedure is made, such that the luminance of the scanning light source approaches a stable state and a better scanning result may be obtained.  
      The procedure of preheating the lamp may be enabled manually. In order to make the scan device in a more human-oriented manner, it is advantageous to the saving of time if the lamp is preheated as a cover is lifted up.  
      In order to detect an open/close state of the cover, a light emitting diode (LED) sensor is conventionally disposed under the glass platen. The open state of the cover may be detected in a normal condition by outputting a light ray to the cover and receiving the light ray reflected by the cover. However, this detecting device has a narrow effective detecting range, and cannot detect the open state of the cover when a document is placed on the glass platen. Another conventional method is to utilize a Hall effect sensor to detect the open state of the cover. However, such a sensor needs an electromagnetic field being created, and the implementation thereof is more complicated.  
       FIG. 1  shows a device of controlling an ON/OFF state of a scanner power by a cover, as disclosed in Taiwan Patent Publication Number 566778. Referring to  FIG. 1 , the scanner includes a casing  101 , a cover  102  and a glass platen  103 . The cover  102  is pivotably connected to the casing  101  through a rotating shaft structure  104 . The casing  101  has a top plate  105  formed with a slot  106 . A sensor  107  corresponding to the slot  106  is disposed under the top plate  105 . The cover  102  has an actuating member  108 , which is inserted into the slot  106  and actuates the sensor  107  when the cover  102  is closed. Although the scanner can detect the opening state of the cover, the inserting of the actuating member  108  will be affected when a large-format document blocks the slot  106 , and the document may be punched through. In addition, this scanner has a complicated structure, and the desired function can be achieved with special designs of the cover and the casing.  
     SUMMARY OF THE INVENTION  
      It is therefore an object of the invention to provide a scan device capable of detecting an open/close state of a cover, wherein the open/close state of the cover is detected according to ambient light without influencing the closing of the cover and the preheating of the lamp or other procedures may be made accordingly.  
      To achieve the above-identified object, the invention provides a scan device including a body, a scanning module disposed in the body, a cover pivotably connected to the body, an optical sensor and a power supply controller. The body has a scan platen, on which a document is placed. The optical sensor, which is disposed either on the cover or the body, receives ambient light and correspondingly outputs an open-state signal. The power supply controller, which is electrically connected to the optical sensor, controls the power supplied to the scanning module according to the open-state signal.  
      Sensing the ambient light to detect the open/close state of the cover can achieve a reliable detection effect. In addition, the procedure of detecting the open/close state of the cover can control a lamp preheating procedure, a printing unit preheating procedure and a document size detecting procedure, so that the time may be saved. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  shows a device of controlling an ON/OFF state of a scanner power by a cover, as disclosed in Taiwan Patent Publication Number 566778.  
       FIG. 2  shows a scan device capable of detecting an open/close state of a cover according to a first embodiment of the invention.  
       FIG. 3  shows a scan device capable of detecting an open/close state of a cover according to a second embodiment of the invention.  
       FIG. 4  shows a scan device capable of detecting an open/close state of a cover according to a third embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       FIG. 2  shows a scan device capable of detecting an open/close state of a cover according to a first embodiment of the invention. Referring to  FIG. 2 , the scan device  10  capable of detecting the open/close state of the cover according to this embodiment of the invention includes a body  20 , a scanning module  30 , a cover  40 , an optical sensor  50  and a power supply controller  60 .  
      The body  20  has a scan platen  22 , on which a document P may be placed. The scanning module  30  including a lamp  32  is disposed in the body  20 . The cover  40  is pivotably connected to the body  20 . The optical sensor  50  disposed on the cover  40  receives ambient light and correspondingly outputs an open-state signal when the cover  40  is opened. For example, the optical sensor  50  may include a light dependent resistor. The resistance of the light dependent resistor is obtained using a voltage-dividing circuit, and the open/close state of the cover may be determined. It is to be noted that the optical sensor  50  disposed on the cover  40  may directly face the scan platen  22  or face a top surface of the body  20  around the scan platen  22 .  
      The power supply controller  60  electrically connected to the optical sensor  50  controls the power supplied to the scanning module  30  according to the open-state signal. For example, the power supply controller  60  controls the lamp  32  to preheat according to the open-state signal. Such a preheating procedure is usually performed after the scan device enters a power sleep mode.  
      Thus, the optical sensor  50  can sense the ambient light when the cover  40  is lifted up, and cannot sense the ambient light when the cover  40  is closed. Alternatively, when the luminance of the ambient light sensed by the optical sensor  50  changes from dark to bright, it means that the cover  40  is lifted up; and when the luminance of the ambient light sensed by the optical sensor  50  changes from bright to dark, it means that the cover  40  is closed.  
       FIG. 3  shows a scan device capable of detecting an open/close state of a cover according to a second embodiment of the invention. As shown in  FIG. 3 , this embodiment is similar to the first embodiment except that the optical sensor  50  is mounted on the body  20  in the second embodiment, and detailed descriptions of the similar parts will be omitted.  
       FIG. 4  shows a scan device capable of detecting an open/close state of a cover according to a third embodiment of the invention. As shown in  FIG. 4 , in addition to all the members included in the first embodiment, the scan device of the third embodiment further includes a printing unit  70 , and the power supply controller  60  controls the printing unit  70  to preheat according to the open-state signal. In addition, the scan device  10  further includes an automatic document feeder  80  and the power supply controller  60  disables the automatic document feeder  80  from transporting a document according to the open-state signal. Thus, it is possible to detect whether the hinge of the automatic document feeder is located at the normal position, and it is possible to prevent the automatic document feeder from transporting the document in an improper condition. Furthermore, this scan device  10  further includes a document size detector  90 , and the power supply controller  60  enables the document size detector  90  to detect the size of the document according to the open-state signal. Because detecting the size of the document before the cover is closed may have good and reliable effects, the invention may also be integrated with this function so that good document size detection effects may be provided.  
      In the scan device of the invention, even if the user has forgotten to take the document out and the document still remains on the glass platen, the open/close state of the cover still can be detected. In addition, only one optical sensor has to be disposed in the scan device of the invention without influencing the effect of detecting the open/close state of the cover. Thus, it is unnecessary to use the prior art method of detecting the open/close state of the cover with the complicated and expensive electromagnetic field or transceiver. Furthermore, the optical sensor may be disposed on a surface, which has the same level as the contact surface of the cover or body, such that the large-format document will not be punched and the closing of the cover will not be influenced as in the &#39;778 patent.  
      While the invention has been described by way of examples and in terms of preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications.