Patent Publication Number: US-2018053171-A1

Title: Reading device and control program for reading device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from. Japanese Patent Application No. 2016-161265, filed Aug. 19, 2016, the entire contents of which are incorporated herein by reference. 
     FIELD 
     Embodiments described herein relate generally to a reading device and a control program for a reading device. 
     BACKGROUND 
     In the related art, a reading device reads tag information stored in a wireless tag (e.g., a Radio Frequency Identification (RFID) tag) attached to merchandise. 
     In an existing reading device having a moving antenna for reading tag information, power supplied from the antenna to the wireless tag may be insufficient or the antenna moves before the tag information has been read, causing failures in the reading of the wireless tag. In a reading device having a fixed antenna, a reading device may fail to read tag information due to the distance between the antenna and the wireless tag being too great. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exterior perspective view of a reading device and a POS terminal according to an embodiment. 
         FIG. 2  is a diagram viewed along the arrow A in  FIG. 1  and a schematic side view illustrating a configuration of a reading device. 
         FIG. 3  is a block diagram illustrating hardware aspects of a point-of-sale (POS) terminal. 
         FIG. 4  is a block diagram illustrating hardware aspects of a reading device. 
         FIG. 5  is a flowchart illustrating a control processing executed by a POS terminal according to an embodiment. 
         FIG. 6  is a block diagram illustrating functional aspects of a reading device. 
         FIG. 7  is a flowchart illustrating a reading process of tag information executed by a reading device according to an embodiment. 
         FIG. 8  is a flowchart illustrating a writing process to a wireless tag executed by a reading device according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In general, according to one embodiment, a wireless tag reading device, comprises an antenna for transmitting wireless signals to a wireless tag so as to initiate reading of information stored in the wireless tag and a moveable stage connected to the antenna and configured to move the antenna from a first location to a second location during a reading process for reading the information from the wireless tag. A controller is configured to determine whether information has been received from the wireless tag during the reading process with the moveable stage at a first location, and to move the moveable stage from the first location to the second location if the information has not been received from the wireless tag during the reading process with the moveable stage at the first location. 
     Hereinafter, a reading device and a control program according to an example embodiment will be described with reference to drawings. In the example embodiment, an article of merchandise M being sold at a store will be described as an example of a tagged article. The reading device receives and reads tag information stored in a wireless tag (e.g., RFID tag) that is attached to the merchandise M. The tag information includes a tag Identification (ID) specifying a wireless tag and a merchandise code specifying the merchandise M. The reading device also transmits and writes information to the wireless tag (e.g., an RFID tag) attached to the merchandise M indicating that settlement processing of the merchandise M has been performed. 
       FIG. 1  is an exterior perspective view of a reading device  30  and a point-of-sale (POS) terminal  1  that are provided in a check-out counter  10 . The POS terminal  1  is installed in a store such as a supermarket or the like and performs sales registration processing and settlement processing related to an article of the merchandise M being purchased by a customer. The reading device  30  reads tag information stored in the wireless tag attached to the merchandise M. The reading is performed using a radio wave in a non-contact manner. 
     The sales registration processing is a process of obtaining a merchandise code related to the merchandise M being sold, then displaying merchandise information such as a merchandise name and/or a price) based on the merchandise code, and storing the merchandise information in merchandise information unit  431  (see  FIG. 3 ). The settlement processing is a process of: displaying a total amount of money due according to the merchandise information stored in the merchandise information unit  431  by the sales registration processing and then calculating and displaying an amount of change due to a customer based on the amount tendered by the customer; instructing a change dispenser to issue the amount of change due; and issuing a receipt on which the merchandise information and settlement information (e.g., the total amount of money due in the sales transaction, a tendered amount, a change due amount, and the like) are printed, and the like. 
     As illustrated in  FIG. 1 , the POS terminal  1  includes a main body  2 , a salesperson display unit  3 , a customer display unit  4 , an operation unit  5 , a code reader  6 , a card reader  7 , a printer  8 , and a drawer  9 . The POS terminal  1  is electrically connected to the reading device  30 . The configuration of the reading device  30  will be described later. 
     The main body  2  includes a controller  400 , a memory unit  44  (see  FIG. 3 ), and a power supply unit (not specifically illustrated) therein. 
     The salesperson display unit  3  is provided on an upper part of the main body  2  towards a salesperson side of the check-out counter  10 . The salesperson display unit  3  displays merchandise information such as a name and a price of the merchandise M read by the code reader  6 . 
     The customer display unit  4  is attached on a customer side of the check-out counter  10  while facing a back surface to the salesperson display unit  3 . The customer display unit  4  displays merchandise information such as a name and a price of the merchandise M read by the code reader  6 . 
     The operation unit  5  includes a key such as a settlement key for declaring an end of sales registration processing of merchandise M being purchased by a customer. If the salesperson display unit  3  may have a function of a touch panel capable of recognizing an instruction by a salesperson&#39;s pressing of keys or buttons, the touch panel corresponds to the operation unit  5 . 
     The code reader  6  is a device which optically reads a code symbol, such as a bar code or a two-dimensional code, attached to each piece of the merchandise M and is disposed so as to be used at a central portion of the check-out counter  10 . The code symbol provides information such as a merchandise code which specifies merchandise and is assigned to each piece of merchandise M in advance. Either a wireless tag T (see  FIG. 2 ) or a code symbol (e.g., a bar code) is affixed to each piece of merchandise M. Hereinafter, the reading device  30  according to the embodiment will be described. A detailed description of aspects of a reading process of the code symbol by the code reader  6  will be omitted. 
     The card reader  7  magnetically or electrically reads information of customer&#39;s a point card (e.g., a customer loyalty card) or a credit card inserted in a card insertion slot. 
     The printer  8  prints merchandise information and settlement information related to the merchandise M on receipt paper. The printing unit  8  issues a receipt on which the merchandise information and the settlement information has been printed. 
     The drawer  9  includes a drawer capable of opening and closing and accommodating cash, securities, and the like. A salesperson stores cash and securities tendered from a customer in the drawer  9 . The salesperson takes out change due from the drawer  9  and hands the change to the customer together with a receipt. 
     Next, the configuration of the reading device  30  will be described.  FIG. 2  is a side view (viewed along the arrow A in  FIG. 1 ) illustrating a schematic configuration of the reading device  30 . The reading device  30  is installed on an opposite side of a surface of the check-out counter  10  on which a customer places merchandise M. The reading device  30  faces a placement position of the merchandise M on a top board of the check-out counter  10 . 
     The reading device  30  reads tag information stored in a wireless tag attached to the merchandise M. In the present example, the wireless tag T is an RFID tag operating in a UHF band. The reading device  30  includes an antenna  22 . As illustrated in  FIG. 2 , the antenna  22  is inside the check-out counter  10 . The antenna  22  is, for example, a planar patch antenna, and has a surface facing the top board of the check-out counter  10 . 
     The reading device  30  transmits radio waves from the antenna  22 . The reading device  30  receives tag information transmitted from the wireless tag T via the antenna  22 . 
     Specifically, the reading device  30  transmits radio waves, including instruction to transmit tag information, to the wireless tag T via the antenna  22 . The wireless tag T receiving the radio waves transmits tag information (such as a tag ID for specifying particular tags and a merchandise code for identifying merchandise M to which the wireless tag T is attached) from the wireless tag T attached to the merchandise M stored therein in advance, to the reading device  30 . The reading device  30  receives the tag information from the wireless tag T via the antenna  22  and stores the received tag information. In addition, the reading device  30  transmits writing information indicating a completion of the settlement processing together with a tag ID to the wireless tag T via the antenna  22 . The wireless tag T corresponding to the tag ID receives the writing information, and stores the writing information in the wireless tag T. When the writing ends, the wireless tag T transmits response information indicating that the writing information is stored to the reading device  30 . The reading device  30  receives the response information. The reading device  30  receiving the response information recognizes that the transmitted writing information has been written to the tag ID. 
     In  FIG. 2 , the antenna  22  emits a radio wave toward a top board of the check-out counter  10 . The top board allows radio waves to pass therethrough and is made of, for example, wood. The reading device  30  has a radio wave coverage area in which the wireless tag T can be read. As illustrated in  FIG. 2 , a customer places the merchandise M to be purchased in the reading area on the check-out counter  10  directly above the antenna  22 . Alternatively, the customer may place a shopping basket (not specifically depicted) containing the merchandise M on the check-out counter  10  above the antenna  22 . The reading device  30  collectively receives and stores tag information stored in the wireless tags T attached to the merchandise M placed in the reading area. 
     The antenna  22  is installed on a moving mechanism  24  disposed under the check-out counter  10 . The antenna  22  so installed is thus able to move in parallel along the top board of the check-out counter  10 . 
     The moving mechanism  24  includes a linear motion mechanism having a screw shaft  18 , a bearing  16  of the screw shaft  18 , a stepping motor  12 , a coupling  14 , and a moveable stage  20 . The stepping motor  12  is a rotational power source. The coupling  14  transmits rotational power of the stepping motor  12  to the screw shaft  18 . The moveable stage  20  is integrated with a ball screw nut screwed to the screw shaft  18 . The antenna  22  is fixed on the moveable stage  20 . 
     One end of the screw shaft  18  is horizontally supported by the bearing  16  and the other end of the screw shaft  18  is horizontally supported by the coupling  14 , so that the screw shaft  18  is rotatable about a horizontal axis (x-axis in  FIG. 2 ). An output shaft  12   a  of the stepping motor  12  is connected with the other end of the screw shaft  18  in the coupling  14 . With this configuration, rotation power of the stepping motor  12  is transmitted from the output shaft  12   a  to the screw shaft  18  via the coupling  14 . 
     The moveable stage  20  has a through hole in a main body thereof and the ball screw nut of the screw shaft  18  is embedded in the through hole. The moveable stage  20  can move along an axial direction of the screw shaft  18  as the screw shaft  18  rotates. That is, the moveable stage  20  moves in the directions of the arrow R 1  and the arrow R 2  in  FIG. 2  along the x-axis. Since a metallic ball (e.g., a steel ball bearing) is interposed in the threaded portion between the screw shaft  18  and the ball screw nut during movement, the moveable stage  20  can move smoothly. It is assumed that the moveable stage  20  moves along the x-axis between x=0 and x=W. The distance between x=0 and x=W can be referred to as a movement range or range of the moveable stage  20 . That is, the moveable stage  20  moves in a range between a rightmost position  20   a  and a leftmost position  20   b.    
     In this manner, the moving mechanism  24  transforms a rotation motion of the stepping motor  12  to a linear motion by a mechanism of the ball screw described above, so that the moveable stage  20  can move linearly. The moveable stage  20  slides while keeping a part of the moveable stage  20  in contact with a supporting plate  11 , such that the moveable stage  20  does not rotate along with the rotation of the screw shaft  18 . Thus, the moveable stage  20  moves without itself rotating. 
     On an upper surface of a main body portion of the moveable stage  20 , the antenna  22  is fixed so that a reading surface of the antenna  22  is facing the top board of the check-out counter  10 . In this context, the reading surface of the antenna  20  refers to a signal radiating surface from which antenna  22  (e.g., a planar patch-type antenna) emits radio waves. Since the antenna  22  is provided in this manner, the antenna  22  emits radio waves from the reading surface toward the top board of the check-out counter  10 . Then, the antenna  22  is moved along the screw shaft  18  integrally with the moveable stage  20 . 
     The reading device  30  may include a position sensor  58  (see  FIG. 4 ) along the path of the moveable stage  20 . The position sensor  58  can output a signal indicating the moveable stage  20  is located at a home position (e.g., a center position between positions of x=0 and x=W). Here, the home position corresponds to a position of the moveable stage at which the antenna  22  is located at a central portion of the merchandise placement position. That is, when at the home position, the antenna  22  would be located proximate to a central portion of the merchandise placement position. 
     The reading device  30  may include the position sensor  58  (for example, a micro-switch, an optical sensor, or the like) at a start position and at an end position of the moveable stage  20 . When the position sensor  58  detects the position of the moveable stage  20 , a controller  500  (see  FIG. 4 ) determines that the antenna  22  is located at the home position and acts to stop the movement of the moveable stage  20 . Accordingly, the reading device  30  can more reliably perform positioning of the moveable stage  20  and thus positioning of the antenna  22  when a position sensor  58  is provided. 
     With the configuration of the moving mechanism  24  described above, if the stepping motor  12  rotates in a first direction, the moveable stage  20  moves on the screw shaft  18  in the direction of the arrow R 2  in  FIG. 2  and if the stepping motor  12  rotates in a second direction (reverse of the first direction), the moveable stage  20  moves on the screw shaft  18  in the direction of the arrow R 1  in  FIG. 2 . The antenna  22  moves integrally with the moveable stage  20  with the reading surface of antenna  22  facing upward towards the top board of the check-out counter  10 . With this movement, the antenna  22  can communicate with the wireless tag(s) T while the position of the antenna  22  with respect to the wireless tag(s) T is changing (that is, changing the location of the reading area of the antenna  22  with respect to the wireless tag(s) T. 
     Hereinafter, hardware configurations of the POS terminal  1  and the reading device  30  will be described.  FIG. 3  is a block diagram illustrating the hardware configuration of the POS terminal  1 . As illustrated in  FIG. 3 , the POS terminal  1  includes a Central Processing Unit (CPU)  41 , a Read Only Memory (ROM)  42 , a Random Access Memory (RAM)  43 , the memory unit  44 , and the like. The CPU  41  is a control main body of the POS terminal  1 . The ROM  42  stores various programs. The RAM  43  develops various programs and various data. The memory unit  44  stores various programs. The CPU  41 , the ROM  42 , the RAM  43 , and the memory unit  44  are connected with each other via a bus  45 . The CPU  41 , the ROM  42 , and the RAM  43  constitute the controller  400 . The controller  400  executes a control program which is stored in the ROM  42  or the memory unit  44  and uses the RAM  43  as a working area. 
     The RAM  43  includes the merchandise information unit  431 . The merchandise information unit  431  obtains and stores merchandise information (merchandise name, merchandise price, and the like) of the merchandise M subjected to the sales registration processing corresponding to a merchandise code obtained from the code symbol read by the code reader  6  or a merchandise code input from the reading device  30 . 
     The memory unit  44  includes a nonvolatile memory such as a Hard Disk Drive (HDD) or a flash memory which holds stored information even if power is turned off. The memory unit  44  includes a control program unit  441  which stores a control program. 
     The controller  400  is connected to the operation unit  5 , the salesperson display unit  3 , the customer display unit  4 , the printer  8 , the code reader  6 , and the card reader  7  via the bus  45  and a controller  46 . The operation unit  5  includes a start key  511  for instructing the reading device  30  to start receiving tag information and a settlement key  512  for ending a transaction with a customer. Upon receiving an instruction from the controller  400 , the controller  46  controls the operation unit  5 , the salesperson display unit  3 , the customer display unit  4 , the printer  8 , the code reader  6 , and the card reader  7 . For convenience of explanation, it is assumed that the controller  400  performs control performed by the controller  46 . 
     The controller  400  is connected with a communication unit  47  via the bus  45 . The communication unit  47  is electrically connected to a communication unit  59  (see  FIG. 4 ) of the reading device  30  via a communication line. 
       FIG. 4  is a block diagram illustrating the hardware configuration of the reading device  30 . As illustrated in  FIG. 4 , the reading device  30  includes a CPU  51 , a ROM  52 , a RAM  53 , a memory unit  54 , and the like. The CPU  51  is a control main body of the reading device  30 . The ROM  52  stores various programs. The RAM  53  develops various programs or various data. The memory unit  54  stores various programs. The CPU  51 , the ROM  52 , the RAM  53 , and the memory unit  54  are connected with each other via a bus  55 . The CPU  51 , the ROM  52 , and the RAM  53  constitute the controller  500 . The controller  500  executes a control program which is stored in the ROM  52  or the memory unit  54  and uses the RAM  53  as a working area. 
     The RAM  53  includes a tag information unit  531 , a counter unit  532 , a counter unit  533 , and a counter unit  534 . The tag information unit  531  stores tag information (e.g., a tag ID and a merchandise code) received from the wireless tag T. The counter unit  532  stores a number X of times radio waves are transmitted from the antenna  22  without receiving any tag information while the antenna  22  remains at the home position. The counter unit  533  stores the number of cycles for later transmitting writing information to the wireless tag from the antenna  22 . Specifically, in a first cycle, the reading device  30  will transmit writing information to each of the wireless tags T from which the antenna  22  has not yet received response information after a first reading attempt. In a second cycle, the reading device  30  will again transmit the writing information to each of the wireless tags T from which the antenna  22  has not yet received the response information after a second reading attempt. The same manner is also applied to a third cycle. Here, the number of cycles refers to the number of this reading-writing cycle (e.g., 1, 2 or 3). While the antenna  22  moves in a range from x=0 to x=W, the counter unit  534  stores the number of cycles. 
     The memory unit  54  includes a nonvolatile memory such as an HDD or a flash memory which holds stored information even if power is turned off. The memory unit  54  includes a control program unit  541  which stores a control program. 
     The controller  500  is connected to the antenna  22 , the stepping motor  12 , and the position sensor  58  via the bus  55  and a controller  56 . 
     The controller  500  is connected to the communication unit  59  via the bus  55 . The communication unit  59  is electrically connected to a communication unit  47  of the POS terminal  1  via a communication line. 
     Hereinafter, control processes by the POS terminal  1  and the reading device  30  will be described.  FIG. 5  is a flowchart illustrating control processing of the POS terminal  1 . As illustrated in  FIG. 5 , the controller  400  of the POS terminal  1  determines whether or not the start key  511  of the operation unit  5  is pressed (S 11 ). When the start key  511  is pressed (Yes in S 11 ), the controller  400  outputs a reading start signal to the reading device  30  (S 12 ). When the reading start signal is received, the reading device  30  transmits a radio wave to a set of all wireless tags T placed in the reading area for reading tag information, receives tag information from a subset of wireless tags T which have responded, and stores the tag information received from the subset of wireless tags T which have responded. Then, the reading device  30  outputs the merchandise code included in the stored tag information to the POS terminal  1 . 
     The controller  400  determines whether or not a merchandise code has been input from the reading device  30  (S 13 ). When the controller  400  waits until the merchandise code is input (No in S 13 ) and determines that the merchandise code has been input (Yes in S 13 ), the controller  400  reads merchandise information (merchandise name, price, or the like) of the merchandise M corresponding to the merchandise code input into the POS terminal  1  and registers the sales of the merchandise M. Specifically, the controller  400  registers the merchandise code stored in the merchandise information unit  431  (S 14 ). In this case, in S 13 , the merchandise code is input together with merchandise codes of other items of the merchandise M corresponding to the subset of wireless tags which have responded, transmitted from the reading device  30  in S 57  described below. Thus, the controller  400  simultaneously registers the merchandise codes of the articles of the merchandise M corresponding to the subset of wireless tags which have responded. Then, the controller  400  displays the merchandise information of each item of the merchandise M including a merchandise name or a merchandise price on the salesperson display unit  3  and the customer display unit  4  and completes a sales registration processing (S 15 ). The controller  400  returns to S 11 . 
     In S 11 , when the start key  511  is not pressed (No in S 11 ), the controller  400  determines whether or not the settlement key  512  is pressed (S 21 ). When the settlement key  512  is pressed (Yes in S 21 ), the controller  400  executes a settlement processing based on the merchandise information stored in the merchandise information unit  431  (S 22 ). Then, the controller  400  outputs a settlement end signal showing that settlement processing of the merchandise M of the merchandise code input in S 13  ends to the reading device  30  (S 23 ). The controller  400  returns to S 11 . In S 23 , the controller  400  may output the merchandise code of the merchandise M subjected to a settlement processing instead of the settlement end signal to the reading device  30 . In addition, in a case where the settlement key  512  has not yet been pressed (No in S 21 ), the controller  400  returns to S 11 . 
     Hereinafter, control of the reading device  30  will be described in detail.  FIG. 6  is a block diagram illustrating a configuration of the reading device  30 . The controller  500  performs functions corresponding to a reception determination unit  501 , a moving control unit  502 , and a writing determination unit  503  by following a control program stored in the control program unit  541  of the ROM  52  or the memory unit  54 . 
     The reception determination unit  501  determines whether or not the antenna  22  has received tag information. 
     The moving control unit  502  drives the moving mechanism  24  for moving the antenna  22  on a condition that the reception determination unit  501  determines that new tag information has not been received. 
     The writing determination unit  503  determines whether or not there is a wireless tag T from which response information has been indicating that the wireless tag T successfully stores the write information transmitted from the antenna  22 . 
     The control processing of the reading device  30  will be described.  FIG. 7  is a flowchart illustrating aspects of a process, executed by the reading device  30 , in which tag information is received from the wireless tag T and stored.  FIG. 8  is a flowchart illustrating aspects of a control process executed by the reading device  30 . As illustrated in  FIG. 7 , the controller  500  controls movement of the antenna  22  toward the home position by driving the stepping motor  12  which causes the moving mechanism  24  to move the moveable stage  20  (S 31 ). Next, the controller  500  determines whether or not the antenna  22  reaches the home position (S 32 ). When the position sensor  58  detects the position of the moveable stage  20 , the controller  500  determines that the antenna  22  has reached the home position. When the controller  500  waits until the antenna  22  reaches the home position (No in S 32 ) and determines that the antenna  22  has reached the home position (Yes in S 32 ), the controller  500  stops movement of the antenna  22  (S 33 ). 
     Next, the controller  500  determines whether or not the reading start signal (output by the processing of the POS terminal  1  in S 12 ) has been received (S 34 ). When the reading start signal has been received (Yes in S 34 ), the controller  500  stores X=0 in the counter unit  532  (S 41 ). Next, the controller  500  (e.g., a reception determination unit  501 ) determines whether or not the number X stored in the counter unit  532  is “3” (S 42 ). When it is determined that X is not “3” (No in S 42 ), the controller  500  transmits a radio wave from the antenna  22  (S 43 ). Since the reading device  30  requires a finite period of time to receive tag information from the wireless tag T, the controller  500  determines whether or not a predetermined time (for example, 2 seconds) has elapsed (S 44 ). When the controller  500  waits until the predetermined time elapses (No in S 44 ) and determines that the predetermined time has elapsed (Yes in S 44 ), the controller  500  determines whether or not new tag information has been received (S 45 ). When the new tag information is received (Yes in S 45 ), the controller  500  stores the newly received tag information in the tag information unit  531  (S 46 ). The controller  500  returns to S 42 . 
     In S 45 , when it is determined that the new tag information is not received (No in S 45 ), the controller  500  increases the number X stored in the counter unit  532  by +1 (S 47 ). The controller  500  returns to S 42 . That is, when the new tag information is received, the controller  500  repeats the cycle of transmission and reception processing of tag information without counting up the number X of the counter unit  532 . When the new tag information is not received, the controller  500  increases the number X of the counter unit  532  by +1 and transmits a radio wave again. 
     In S 42 , when it is determined that the number X stored in the counter unit  532  is “3” (that is, the reception determination unit  501  determines that new tag information has not been received after three cycles) (Yes in S 42 ), the controller  500  (in particular, moving control unit  502 ) initiates movement of the antenna  22  from its home position (S 51 ). The antenna  22  moves in a range from x=0 to x=W. The controller  500  executes processing of transmitting a radio wave to the wireless tag(s) T attached to the merchandise M placed on the check-out counter  10  (S 52 ). That is, when the number of times new tag information is not read equals 3 times, the controller  500  determines that it will be difficult to receive further tag information with the antenna  22  located at the home position. Thus, the controller  500  causes the antenna  22  to move away from the home position and starts the process of transmitting a radio wave to and receiving tag information from the wireless tag T while changing a relative position of the antenna  22  to the wireless tag T by moving the antenna  22 . Then, the controller  500  determines whether or not a predetermined time has elapsed (S 53 ). The predetermined time in S 53  is, for example, a time required for the antenna  22  to reciprocate once in the range from x=0 to x=W. The predetermined time in S 53  may be, for example, any arbitrary time, for example, a time period required for the antenna  22  reciprocate twice or three times in the range from x=0 to x=W, or any other time period. 
     After the controller  500  waits until the predetermined time elapses (No in S 53 ) and then determines that the predetermined time has elapsed (Yes in S 53 ), the controller  500  stops movement of the antenna  22  (S 54 ). Then, the controller  500  determines whether or not new tag information has been received (S 55 ). When the new tag information has been received (Yes in S 55 ), the controller  500  stores the tag information determined to be newly received in the tag information unit  531  (S 56 ). Then, the controller  500  transmits the merchandise codes included in the stored tag information corresponding to the subset of wireless tags that have been read to the POS terminal  1  (S 57 ). The controller  500  returns to S 31 . When it is determined that the new tag information has not been received (No in S 55 ), the controller  500  executes processing of S 57  instead of S 56 . 
     In S 34 , when it is determined that a reading start signal has not been input (No in S 34 ), the controller  500  determines whether or not a settlement end signal (output by the processing of the POS terminal  1  in S 23 ) has been received (S 35 ). When it is determined that the settlement end signal has been received, the controller  500  returns to S 31 . 
     Writing of tag information will be described with reference to  FIG. 8 . When the settlement end signal is input (Yes in S 35 ), the controller  500  sets a number Y to be “0” stored in the counter unit  533  (S 61 ). At this time, the controller  500  executes processing in S 31  to S 33  to move the antenna  22  to the home position. Next, the controller  500  (in particular, the writing determination unit  503 ) determines whether or not the number Y stored in the counter unit  533  is “3” (that is, there is a tag from which response information has not been received yet) (S 62 ). When the writing determination unit  503  determines that there are wireless tags T from which response information has not been received, those wireless tags T do not store write information. When the number Y stored in the counter unit  533  is not “3” (No in S 62 ), the controller  500  specifies one wireless tag among the subset of the wireless tags for which tag information stored in the tag information unit  531  (S 63 ). For example, the controller  500  specifies one wireless tag T in the order that is stored in the tag information unit  531 . 
     Next, the controller  500  executes a writing process of transmitting information including writing information indicating that settlement processing related to the article of the merchandise M to which the specified wireless tag T is attached ends (S 64 ). This information also includes a tag ID specifying the wireless tag T. When receiving the information from the reading device  30 , the wireless tag T specified by the tag ID stores writing information indicating that the settlement processing for the specified wireless tag T has been completed. The wireless tag T transmits response information indicating that the writing information is stored in the specified wireless tag T to the reading device  30 . 
     The controller  500  determines whether or not a predetermined time has elapsed after the processing in S 64  (S 65 ). Since the wireless tag T requires a finite period of time to receive information from the reading device  30  and transmit response information, the controller  500  determines whether or not a predetermined time has elapsed. The predetermined time in S 65  is longer than the predetermined time in S 44  (for example, 3 seconds). After the controller  500  waits until the predetermined time elapses (No in S 65 ) and determines that the predetermined time has elapsed (Yes in S 65 ), the controller  500  determines whether or not response information has been received from specified wireless tag T (S 66 ). When it is determined that the response information has been received (Yes in S 66 ), the controller  500  stores a flag indicating that response information has been received (that is, information indicating that settlement processing has completed successfully is stored in the wireless tag T) corresponding to the specified wireless tag T stored in the tag information unit  531  (S 69 ). 
     Next, the controller  500  determines whether or not response information has been received from all of wireless tags T by reference to the completion flag stored in the tag information unit  531  (S 70 ). That is, the controller  500  determines whether or not there are wireless tags in which writing information has not yet been stored. When the response information has been received from all of the wireless tags T (Yes in S 70 ), the controller  500  returns to S 31 . 
     In S 66 , when the response information has been not received from a specified wireless tag T (No in S 66 ), the controller  500  determines whether or not the process of specifying the wireless tag T in S 63  has been previously attempted (S 67 ). When the process of specifying the wireless tag T has not just been attempted (No in S 67 ), the controller  500  returns to S 62  and specifies a next wireless tag T in S 63 . When the wireless tag T has been previously attempted (Yes in S 67 ), the controller  500  increases the number Y stored in the counter unit  533  by +1 (S 68 ). Then, the controller  500  returns to S 62  and attempts a specifying process of wireless tag T as a second cycle in S 63 . In the second cycle and the following cycles, processing of S 63  to S 70  is executed only for the wireless tag(s) T for which a completion flag has not been stored in the tag information unit  531 . In S 70 , when it is determined that the response information has not been received from all of the wireless tags T (No in S 70 ), the controller  500  executes the processing in S 67  and so forth. 
     In S 62 , when it is determined that the number Y stored in the counter unit  533  is “3” (that is, there are wireless tags from which response information has not been received) (Yes in S 62 ), the controller  500  sets a number Z to be “0” stored in the counter unit  534  (S 81 ). Next, the controller  500  determines whether or not response information is received from all of wireless tags T by reference to the completion flag stored in the tag information unit  531  (S 82 ). When the response information has been received from all of the wireless tags T (Yes in S 82 ), the controller  500  returns to S 31 . When it is determined that the response information has not been received from all of the wireless tags T (No in S 82 ), the controller  500  determines whether or not the number Z stored in the counter unit  534  is “3” (S 83 ). When the number Z stored in the counter unit  534  is not “3” (No in S 83 ), the controller  500  specifies one wireless tag for which the completion flag has not been stored from among the wireless tags for which tag information has been stored in the tag information unit  531  (S 84 ). 
     Next, the controller  500  controls movement of the antenna  22  away from its home position (S 85 ). The antenna  22  moves in a range from x=0 to x=W. The controller  500  executes writing processing to the wireless tag T specified in S 84  (S 86 ). Then, the controller  500  determines whether or not a predetermined time has elapsed (S 87 ). The controller  500  waits for predetermined time to elapse (No in S 87 ) and once it has been determined that the predetermined time has elapsed (Yes in S 87 ), the controller  500  stops movement of the antenna  22  (S 88 ). 
     Next, the controller  500  determines whether or not response information has been received from the specified wireless tag T (S 89 ). When it is determined that the response information has been received (Yes in S 89 ), the controller  500  stores a completion flag in the tag information unit  531  indicating that response information has been received from the specified wireless tag T (S 90 ). 
     Next, the controller  500  determines whether or not the process of specifying the wireless tag T in S 84  has been attempted once (S 91 ). In addition, when the specifying process of the wireless tag T has not been attempted (No in S 91 ), the controller  500  returns to S 82  and specifies next wireless tag T in S 84 . On the other hand, in a case where specifying of the wireless tag T was attempted (Yes in S 91 ), the controller  500  increases the number Z stored in the counter unit  534  by +1 (S 92 ). Then, the controller  500  returns to S 82  and specifies a wireless tag T as a second cycle while moving the antenna  22  in S 84 . In the second cycle and the following cycles, processing of S 83  to S 92  is executed only for the wireless tag T of which a flag has not been stored in the tag information unit  531 . In S 89 , when it is determined that the response information has not been received (No in S 89 ), the controller  500  executes determination processing in S 91 . 
     In S 83 , when it is determined that the number Z stored in the counter unit  534  is “3” (Yes in S 83 ), the controller  500  executes error processing of showing that response information has not been received from the specified wireless tag T (S 93 ). The controller  500  returns to S 31 . 
     That is, while the antenna  22  remains at the home position, the controller  500  attempts three times the processing of transmitting information including writing information to the specified wireless tags T. Then, when information of a settlement end has not been written to all of the specified wireless tags T, the controller  500  tries to attempts the processing of transmitting information including writing information to the specified wireless tags T for three times while moving the antenna  22 . That is, when the controller  500  determines that information indicating an end of settlement processing cannot be written to the wireless tag(s) T when the antenna  22  remains at the home position, the controller  500  transmits information including writing information while changing a relative position of the antenna  22  to the wireless tag T by moving the antenna  22 . 
     As described above, in the reading device  30  of the embodiment, the controller  500  receives tag information stored in the wireless tag T while the antenna  22  is stopped. When it is determined that new tag information has not been received, the controller  500  then controls movement of the antenna  22  so that it can receive tag information. Thus, the tag information which cannot be received when the antenna  22  is stopped can be received, and it is possible to more reliably read the tag information. 
     In addition, in the reading device  30  of the embodiment, writing information is transmitted to the wireless tags T while the antenna  22  is stopped. But then, if the writing information cannot be written to all of the specified wireless tags T, the controller  500  transmits the writing information to the wireless tags T while moving the antenna  22 . For this reason, since the writing information which cannot be written when the antenna  22  is stopped may be written to the wireless tag T while the antenna  22  is moving (or moved), it is thus possible to more reliably write and confirm the writing information. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions. 
     In an example embodiment, tag information is received from a wireless tag T while the antenna  22  is moving. However, the present disclosure is not limited thereto. For example, the tag information may be received while the antenna  22  is temporarily stopped at some predetermined position or positions (for example, with antenna  22  moved by a predetermined incremental distance or a for a predetermined time increment). In addition, moving and stopping the antenna  22  for receiving the tag information may be repeated several times. 
     In an example embodiment, information is written to specific wireless tags T the antenna  22  is moving. However, the present disclosure is not limited thereto. The information may be written to the wireless tag while antenna is temporarily stopped after being moved by some predetermined distance. In addition, moving and stopping the antenna  22  during the writing of information to the wireless tag(s) T may be repeated several times. 
     In addition, in an example embodiment, the reading device  30  receives tag information from a wireless tag T attached to an article of merchandise M being sold in a store, for example. However, the present disclosure is not limited thereto. For example, the reading device  30  may receive the tag information from the wireless tag T attached to an article other than merchandise being sold at store and the article may be, for example, a document. 
     A program executed by the reading device  30  according to the example embodiment is recorded and provided in a computer-readable recording medium such as a CD-ROM, a floppy disk (FD), a CD-R, or a Digital Versatile Disk (DVD) as a file in installable format or executable format. 
     The program executed by the reading device  30  according to an example embodiment may also be saved on a computer connected to a network such as the Internet and provided by downloading the program via a network. The program executed by the reading device  30  according to an example embodiment may also be provided and distributed via a network such as the Internet. 
     The program executed by the reading device  30  according to an example embodiment may be incorporated in advance in ROM or the like.