Patent Publication Number: US-2022214644-A1

Title: Image forming apparatus

Description:
FIELD OF THE INVENTION 
     The present invention relates to an imaging forming apparatus such as a printer, a copier, a fax machine, or a multifunction device, provided with a wireless communication function which enables wireless communication with a communication terminal. 
     BACKGROUND ART 
     In recent years, with a spread of a use of communication terminals such as a smartphone and a tablet terminal in a business application, it is required for an image forming apparatus to expand its function to work with the communication terminals. For this reason, a trend to improve a usability of the image forming apparatus by being provided with short range wireless communication functions such as Bluetooth (registered trademark). 
     Bluetooth is a wireless communication system which uses a 2.4 GHz ISM (Industrial Scientific and Medical) band, as well as other communication systems such as Wi-Fi (registered trademark). And Bluetooth Low Energy (hereinafter, referred to as BLE) is a part of a Bluetooth standard, and is a close proximity wireless communication system with lower power consumption than a conventional Bluetooth. 
     In particular, BLE is applied to various functions by controlling a position. And an image forming apparatus, which loads the BLE communication function and performs a short range wireless communication with a communication terminal, is popular. In Japanese Laid-Open Patent Application (JP-A) 2017-173189, a technology, which detects a distance between an image forming apparatus and a communication terminal by a radio wave strength when the communication terminal receives a BLE communication radio wave which is transmitted from the imaging forming apparatus. 
     PROBLEM TO BE SOLVED BY THE INVENTION 
     As mentioned above, as for BLE, a method of determining a distance between devices, based on a radio wave strength, is widely known, and applied. Besides, in a BLE communication function by Bluetooth 5.1, a function, to detect a direction in which a device is located between devices by detecting an arrival direction of a radio wave, is added by an upgrading of the Bluetooth standard, in addition to determining a conventional distance. In this case, in order to detect the arrival direction of the radio wave, it is necessary to arrange a plurality of antennas and to detect differences in phase and time of the radio waves which are sent and received between the plurality of antennas. 
     However, conventionally, an image forming apparatus including a plurality of antennas for detecting an arrival direction of a radio wave was not invented. 
     The present invention is made in consideration of the problems described above, and its object is to improve a performance of the image forming apparatus by using a plurality of antennas to detect an arrival direction of a radio wave. 
     MEANS FOR SOLVING THE PROBLEMS 
     A typical constitution of the present invention is an image forming apparatus including an image forming unit configured to form an image on a sheet, which is provided with a main assembly including the image forming unit therein, a reading device provided above the main assembly with respect to a vertical direction and for reading an image of an original, an operating portion provided on a front side of the reading device with respect to a front-rear direction of the image forming apparatus and above the main assembly with respect to the vertical direction, and operable by a user, and a communication board provided with a plurality of antennas for detecting for an arrival direction of a radio wave, the plurality of antennas being arranged along a horizontal direction, wherein the communication board is provided on a front side of the image forming apparatus with respect to the front-rear direction. Further, another typical constitution of the present invention is an image forming apparatus including an image forming unit configured to form an image on a sheet, which is provided with a main assembly including the image forming unit therein, a reading device provided above the main assembly with respect to a vertical direction and for reading an image of an original, an operating portion provided on a front side of the reading device with respect to a front-rear direction of the image forming apparatus and above the main assembly with respect to the vertical direction, and operable by a user, and a communication board provided with a plurality of antennas for detecting for an arrival direction of a radio wave, the plurality of antennas being arranged along a horizontal direction, wherein the communication board is provided at a position projecting from an upper surface of the reading apparatus with respect to the vertical direction of the image forming apparatus and where the plurality of antennas are not overlapped with any other portions as viewed from a front of the image forming apparatus. Further, another typical constitution of the present invention is an image forming apparatus including an image forming unit configured to form an image on a sheet, which is provided with a main assembly including the image forming unit therein, a reading device provided above the main assembly with respect to a vertical direction and for reading an image of an original, an operating portion provided on a front side of the reading device with respect to a front-rear direction of the image forming apparatus and above the main assembly with respect to the vertical direction, and operable by a user, and a communication board provided with a plurality of antennas for detecting for an arrival direction of a radio wave, the plurality of antennas being arranged along a horizontal direction, wherein the communication board is provided so as to project from a side surface of the image forming apparatus with respect to a widthwise direction of the image forming apparatus. 
     According to the present invention, it is possible to improve a performance of an image forming apparatus by using a plurality of antennas to detect an arrival direction of a radio wave. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic sectional view of an image forming apparatus. 
         FIG. 2  shows a constitution of an image forming apparatus. 
         FIG. 3  is a block diagram illustrating a control portion. 
         FIG. 4  is a block diagram showing a BLE communication board. 
         FIG. 5  is a schematic view showing a BLE communication board. 
         FIG. 6  is a view illustrating a direction detection by BLE. 
         FIG. 7  is a view illustrating an arrangement of a BLE communication unit. 
         FIG. 8  is a view showing an outer cover which covers a BLE communication unit. 
         FIG. 9  is a view illustrating a detection of a user&#39;s movement locus by BLE. 
         FIG. 10  is a flow chart illustrating an operation of sleep restoration by BLE communication. 
         FIG. 11  is a flow chart illustrating an operation of user authentication by BLE communication. 
         FIG. 12  is a view illustrating an arrangement of a BLE communication unit in a second embodiment. 
         FIG. 13  is a view illustrating an arrangement of a BLE communication unit in a third embodiment. 
         FIG. 14  is a view showing an outer cover which covers a BLE communication unit in a third embodiment. 
         FIG. 15  is a view illustrating an arrangement of a BLE communication unit in a fourth embodiment. 
         FIG. 16  is a view showing an outer cover which covers a BLE communication unit in a fourth embodiment. 
         FIG. 17  is a view illustrating an arrangement of a BLE communication unit in a fifth embodiment. 
         FIG. 18  is a view showing an outer cover which covers a BLE communication unit in a fifth embodiment. 
         FIG. 19  is a view illustrating an arrangement of a BLE communication unit in a sixth embodiment. 
         FIG. 20  is a view illustrating an arrangement of a BLE communication unit in a sixth embodiment. 
         FIG. 21  is a view showing an outer cover which covers a BLE communication unit in a sixth embodiment. 
         FIG. 22  is a view illustrating an arrangement of a BLE communication unit in a seventh embodiment. 
         FIG. 23  is a view showing an outer cover which covers a BLE communication unit in a seventh embodiment. 
     
    
    
     EMBODIMENTS FOR CARRYING OUT THE INVENTION 
     Optimum forms for implementing the present invention will be described with reference to drawings below. Incidentally, dimensions, materials, shapes, relative arrangements, etc., of components described below are not intended to limit a scope of the present invention only to them, unless it is specifically described. 
     Embodiment 1 
     First, an image forming apparatus of the embodiment will be described by using  FIGS. 1  and  FIG. 2 .  FIG. 1  is a schematic sectional view of the image forming apparatus  50 .  FIG. 2  is a view showing a constitution of the image forming apparatus, where part (a) of  FIG. 2  is a perspective view of an external appearance, part (b) of  FIG. 2  is a front view while a feeding portion  50   b   1  is in a closed state, part (c) of  FIG. 2  is a side view, part (d) is a back view, and part (e) of  FIG. 2  is a front view while a feeding portion  50   b   1  is in an open state. 
     An image forming apparatus  50  described in  FIG. 1  is a tandem type full color printer of an electrophotographic method. The image forming apparatus  50  includes a main assembly  50   a  which includes an image forming portion  500  as an image forming means, and a reading device  50   b  which reads an image of an original. 
     The reading device  50   b  includes a feeding portion  50   b   1  which feeds originals stacked on a loading tray one by one, and a reading portion  50   b   2  which includes the unshown reading unit such as CIS or CCD inside and reads an image of an original fed from the feeding portion  50   b   1  or an image of an original which is placed on an unshown original table glass by the reading unit. The feeding portion  50   b   1  is rotatable with respect to the reading portion  50   b   2  by a hinge mechanism, and is possible to place an original on the unshown original table glass by opening the feeding portion  50   b   1  with respect to the reading portion  50   b   2  as shown in part (e) of  FIG. 2 . 
     And the image forming apparatus  50  is possible to form an image on a recording material P based on image data sent from the reading device  50   b,  an external terminal such as a computer, a mobile communication terminal  53  such as a smart phone which is communicating by a wireless communication, etc. 
     In a case of the embodiment, the image forming apparatus  50  includes the image forming portion  500  as an image forming means for forming an image on the recording material P in the main assembly  50   a.    
     Incidentally, various types of sheet materials, such as a plain paper, a thick paper, a rough paper, an uneven paper, a coated paper, a glossy paper, a photographic paper, a plastic film, a cloth, are used as the recording material P. 
     Next, we will describe the image forming section  500  in detail. The image forming portion  500  is provided with an image forming portion  10  which is possible to form yellow, magenta, cyan, and black images. The image forming portion  10  includes image forming units  1   a,    1   b,    1   c,  and  1   d  which are arranged along a peripheral direction of an intermediary transfer belt  58 . Here, the  1   a  is a unit which forms an image by yellow color toner, the  1   b  is a unit which forms an image by magenta color toner, the  1   c  is a unit which forms an image by cyan color toner, and the  1   d  is a unit which forms an image by black toner. 
     The image forming units from  1   a  to  1   d  include rotatable photosensitive drums from a to d, charging devices from  80   a  to  80   d,  and developing devices from  81   a  to  81   d,  respectively. The photosensitive drums from a to d are exposed by laser beams corresponding to an image data which are emitted from a laser scanner  82  after being charged by corresponding charging devices from  80   a  to  80   d.    
     As a result, electrostatic latent images corresponding to the image data are formed on surfaces of the photosensitive drums a through d. And the electrostatic latent images formed on the photosensitive drums from a to d are developed to toner images by the developing devices from  81   a  to  81   d  using each color developers. 
     Each of toner images formed on the photosensitive drums from a to d is primarily transferred to an intermediary transfer belt  83  in respective primary transfer nip portions N 1  by applying primary transfer bias to primary transfer rollers from  2   a  to  2   d  which are arranged on an inner periphery side of the intermediary transfer belt  83  opposing to the photosensitive drums from a to d. 
     The intermediary transfer belt  83  is stretched by a secondary transfer inner roller  84 , a secondary transfer outer roller  85 , and a stretching roller  86 . The secondary transfer outer roller  85  is arranged at a position opposing to the secondary transfer inner roller  84  via the intermediary transfer belt  83  and form a secondary transfer nip portion N 2  to secondarily transfer a toner image on the intermediary transfer belt  83  to the recording material P. 
     A sheet feeding cassette  87  on which the recording material P is stacked is arranged at a bottom of the image forming apparatus  50 . The recording material P is fed one by one from the sheet feeding cassette  87  by the feed roller  88  into the feeding passage  89 . The recording material P fed from the sheet feeding cassette  87  is fed through the feeding passage  89  to a registration roller pair  90 . Although only one sheet feeding cassette  87  is described in  FIG. 1 , a constitution which includes a plurality of sheet feeding cassettes may be used as shown in part (a) of  FIG. 2 . Further, a feeding device  200 , which is provided separately from the image forming apparatus  50  as an optional device, may be constituted to be mounted to a bottom of the image forming apparatus  50 . The paper cassette  87  is an example of a storage section that holds sheets to be fed to the image forming section  500 . 
     The registration roller pair  90  feeds the recording material P to the secondary transfer nip portion N 2  in accordance with a timing of forming a toner image on the intermediary transfer belt  83  in each of image forming units from  1   a  to  1   d  after stopping a feeding of the recording material P and correcting a skewness of the recording material P. 
     And by applying a secondary transfer bias to the secondary transfer outer roller  85 , the toner image on the intermediary transfer belt  83  is secondarily transferred to the recording material P at the secondary transfer nip portion N 2 . Subsequently, the recording material P is fed to a fixing device  40 . In the fixing device  40 , as the recording material P is nipped and fed by a roller pair which form a fixing nip portion, the toner image is fixed to the recording material P by being heated and pressurized. 
     In a case of forming a toner image on only one side of the recording material P, the recording material P, which is passed through the fixing device  40 , is discharged onto a discharge tray  92  by a discharging roller pair  91 . In the embodiment, the discharging roller pair  91  discharges a sheet to the discharge tray  92  from a right side to a left side with respect to a right and left direction of the image forming apparatus  50 . And, in a case of forming toner images on both sides of the recording material P, the recording material P, which is passed through the fixing device  40 , is switched back and fed to a double sided feeding passage  93  by the discharging roller pair  91 . 
     The recording material P, which is sent to the double sided feeding passage  93 , is returned to the feeding passage  89  by a feeding roller pair  94 , and a toner image is formed on the other side through a same process at a time of forming a toner image on one side. And the recording material P, of which the toner images are fixed on both sides, is discharged onto the discharge tray  92  by the discharging roller pair  91 . 
     Further, as shown in  FIG. 1 , the image forming apparatus  50  includes an operation portion  400  by which it is possible for a user to input operation instructions. In a case of the embodiment, the operation portion  400  is provided with a display portion  410 , which is able to display various screens such as an input screen, for example, including soft keys (not shown) which imitate shapes of actual operation elements, such as a switch, a button, a numeric keypad, etc., and an outer cover  420 . 
     In a case that soft keys are displayed in the display portion  410 , various functions, which are assigned to the soft keys in advance, are executed in accordance to touch operations on the soft keys by a user. That is, the display portion  410  is a display panel such as a liquid crystal display or an organic EL display, for example, and a touch panel type display which is provided with a touch panel in which a touch operation by a user is possible, etc. 
     By a touch operation of the soft keys displayed on the display portion  410 , it is possible for a user to input various data related to an image forming, give a start instruction and an end instruction of an image forming operation. Further, the display portion  410  is surrounded by the outer cover  420  so that a display surface is exposed. 
     The operation portion  400  is provided on a front side of the main assembly  50   a  where a user is positioned during an operation, as shown in part (a) of  FIG. 2 . In a case that a side which is provided with the operation panel  400  is a front, a right and left direction when the image forming apparatus  50  is viewed from the front side is a width direction of the image forming apparatus  50 , and a direction from the front to the rear is a front and rear direction. Further, an up and down direction is a vertical direction in part (a) of  FIG. 2 . 
     As shown in part (a) of  FIG. 2 , on the front side of the main assembly  50   a  of the image forming apparatus  50 , a front cover  100 , which is an outer cover to be opened when accessing the image forming portion  500  for maintenance (replacement of the image forming units from  1   a  to  1   d  and an unshown toner accommodating container, etc.) of the image forming portion  500 , etc. The front cover  100  is possible to open and close with respect to the main assembly  50   a  by an unshown hinge mechanism. 
     Incidentally, the operation panel  400  is provided on the main assembly  50   a  so that it is possible to adjust an angle or a position in an up and down direction or a right and left direction by a tilt mechanism or a vari angle mechanism, for example. Incidentally, the operation portion  400  may be immobile with respect to the main assembly  50   a,  as long as it is possible to receive an operation from a user. Further, a constitution, in which the operation portion  400  includes a display portion  410  with a touch panel, is described in the embodiment, however, it may be any other form as long as it is operable by a user, such as one with a display which does not include a touch panel, or one with hard keys which is operable by a user. 
     The image forming apparatus  50  is provided with a BLE communication unit  5  inside the outer cover  65  which performs a short range wireless communication with a communication terminal  53  by BLE (Bluetooth Low Energy). The BLE communication unit  5  is provided in a form of a board module which is constituted on a printed circuit board. 
     The outer cover  65  is arranged above the discharge tray  92  in a vertical direction, and a cover member which constitutes an outer appearance on a front side of the feeding portion  50   b   1  of the reading device  50   b.  Further, the outer cover  65  is arranged above the discharging roller pair  91  in a vertical direction of the image forming apparatus  50  and constitutes an outer appearance of the image forming apparatus on a front side of the feeding portion  50   b   1  of the reading device  50   b.  Further, the outer cover  65  constitutes the outer appearance of the image forming apparatus  50  above the operation portion  400  in a vertical direction of the image forming apparatus  50 . 
     In a case of the embodiment, the BLE communication unit  5  communicates according to IEEE 802.15 standard (what has been referred to as Bluetooth (registered trademark)). Specifically, it uses a low power consumption BLE (Bluetooth Low Energy) which is a part of Bluetooth standard, and performs wireless communication by using an ISM (Industrial, Scientific and Medical) band of a 2.4 GHz band. Incidentally, in the embodiment, the BLE communication unit  5  supports a BLE communication method of a Bluetooth 5.1, and supports a function of detecting a direction of the communication terminal  53  by the BLE communication. 
     Further, in the embodiment, the BLE communication unit  5  is arranged on a front side of the reading device  50   b  of the image forming apparatus  50  and on the feeding portion  50   b   1  which is above the discharge  92 , and is covered by the outer cover  65 . Incidentally, the front side of the reading device  50   b  is a position on a front side of the unshown reading unit, which is accommodated inside the reading portion  50   b   2 , and is a position on a front side of a support frame, which is a metal frame of the reading device  50   b.  Further, the front side of the reading device  50   b  is a position on a front side of support frames which support each configuration of the feeding portion  50   b   1  of the reading device  50   b.    
     Further, the BLE communication unit  5  in the embodiment is provided in a position where it does not overlap with the operation portion  400  when the image forming apparatus  50  is viewed from the front side, even in a case that the operation portion  400  is rotated with respect to the main assembly  50   a.    
     In many cases, a user who carries the communication terminal  53  comes close to a front side of the image forming apparatus  50  to operate the operation portion  400  of the image forming apparatus  50 . For details, it will be described below, however, in order to detect a direction by BLE communication of Bluetooth 5.1, it is necessary to send and receive a direct wave of a wireless radio wave which reaches in a straight line between the image forming apparatus  50  and the communication terminal  53  which is carried by the user. 
     In the embodiment, by arranging the BLE communication unit  5  on a front side of the main assembly  50   a  of the image forming apparatus  50 , it is possible to send and receive the direct waves of the wireless radio wave with a sufficient radio wave strength without being affected by shielding of the radio wave by the main assembly of the image forming equipment  50 , etc., in BLE communication with the communication terminal  53  which is carried by the user. For example, in a case that the BLE communication unit  5  is arranged on a rear side of the image forming apparatus  50 , it may not be possible to obtain a sufficient radio wave strength since the radio wave is shielded by a unit inside the image forming apparatus  50  or the reading device  50   b.  However, in the embodiment, by arranging the BLE communication unit  5  on a front side of the main assembly  50   a  of the image forming apparatus  50 , it is possible to suppress the radio wave from being shielded by the image forming apparatus  50  itself 
     Further, by providing the BLE communication unit  5  in a vicinity of the operation panel  400  in a vertical direction, it is possible to detect a user carrying the communication terminal  53  more accurately who approaches the image forming apparatus  50  to operate the operation unit  400 . 
     Further, the BLE communication unit  5  is arranged in the feeding portion  50   b   1  which is in a vicinity of the operation unit  400  and above an upside of the operation unit  400  in a vertical direction, that is at a relatively high position in the image forming apparatus  50 . Here, the relatively high position with respect to the image forming apparatus  50  means a position above the discharge tray  92  and above the main assembly  50   a  in the vertical direction. Here, the position above the discharge tray is a position vertically above all of sheet loading surfaces of the discharge tray  92 . Further, the relatively high position with respect to the imaging forming apparatus  50  is a position above the discharging roller pair  91  in a vertical direction. In this way, by arranging the BLE communication unit  5  at the relatively high position in the main assembly  50   a,  it is possible to send and receive the direct wave of the wireless radio wave with sufficient radio wave strength, avoiding an influence of obstacles which exist between the image forming apparatus  50  and the communication terminal  53 . Incidentally, details of each constitution and arrangement of the BLE communication unit  5  will be described below. 
     As shown in  FIG. 1 , the image forming apparatus  50  is provided with a control portion  300  which controls an operation of the image forming portion  500 . In the embodiment, the BLE communication unit  5  is arranged on a front side of the reading device  50   b  as shown in parts (a) and (b) of  FIG. 2 , while the control portion  300  is arranged on a rear side of the main assembly  50   a  as shown in parts (c) and (d) of  FIG. 2 . 
     Thus, the BLE communication unit  5  and the control portion  300  are electrically connected by a cable  5 . Since the cable  5   a  is passed through a cable guide  600 , which is provided with the main assembly  50   a,  is wired from a front surface to a rear surface in the main assembly  50   a,  it is easy to wire in the main assembly  50   a  and is designed to enhance workability when the image forming apparatus  50  is assembled or maintained. 
     As shown in part (e) of  FIG. 2 , a cable guide  600  is arranged to avoid an area  601  through an inside of the feeding portion  50   b   1 . This is because, in the feeding portion  50   b   1 , each mechanism such as rollers for separating, feeding, and discharging documents is arranged in the area  601 , and the cable guide  600  is arranged to avoid this. Since the cable  5   a  passes through the cable guide  600  and is arranged from a front side of the feeding portion  50   b   1  to a rear side of the main assembly  50   a,  an operability is improved in a case of assembling or maintaining the image forming apparatus  50 . 
     The control portion  300  will be described using  FIG. 3  with reference to  FIG. 1 . However, the control portion  300  is connected to various devices other than those shown in the figures, such as each of portions which constitute the image forming portion  500  including the image forming portion  10  and drive sources (motor, power source, etc.) for operating each of the portions. 
     The control portion  300  as a control means controls various operations of the image forming portion  500  such as data communication and image formation, and includes, for example, a CPU  301  (Central Processing Unit) and a memory  302 . The memory  302  is constituted of a ROM (Read Only Memory) and RAM (Random Access Memory), etc. 
     The memory  302  stores various programs for controlling the image forming apparatus  50  and various data such as connection setting data and authentication data for communication between the image forming apparatus  50  and the communication terminal  53 . Here, the memory  302  is an example of a storage means for storing various data such as an ID list of authenticatable users. 
     The CPU  301  is capable of executing various programs such as “communication control processing (program)” and “image forming job processing (program)” (not shown), for example, which are stored in the memory  302 , and controls an operation of the image forming apparatus  50  by executing the various programs. 
     Incidentally, the memory  302  is also capable of temporarily storing results of arithmetic processing which are accompanied by executions of various programs, terminal information and image data which are received from the communication terminal  53 , etc. 
     The control portion  300  is connected to a memory device  303 , a display control portion  304 , the BLE communication unit  5 , etc. via an input and output interface. The memory device  303  is capable of storing various programs, various data, etc. as well as the memory  302 , and is capable of sending and receiving various programs, various data, etc. between the memory device  303  and the memory  302 . 
     The display control portion  304  performs various controls related to the display portion  410  such as displaying various screens, soft keys, etc. on the display portion  410 . 
     The BLE communication unit  5  performs wireless communication according to BLE with the communication terminal  53 , and controls data input and output between the communication terminal  53  and the control portion  300 . 
     Examples of the communication terminals  53  are a smart phone, a tablet, or a laptop computer, or a digital camera. The communication terminal  53  includes a BLE communication board (not shown) and is capable of performing wireless communication with the BLE communication unit  5  which is arranged in the image forming apparatus  50 . Here, in a case that the communication terminal  53  includes a communication mode by BLE, it is a device which is capable of performing a wireless communication by BLE with other devices having a BLE communication board by setting its mode to ON. Incidentally, the device may be capable of performing a wireless communication by BLE without switching the communication mode. 
     A constitution of the BLE communication unit  5  described above will be described with reference to  FIG. 4  and  FIG. 5 . As shown in  FIG. 4 , in the BLE communication unit  5 , a host OF control portion  31 , a BLE baseband portion  32 , a RF control portion  33 , a RF switch  34 , a BLE antenna  35 , a BLE antenna  36 , a BLE antenna  37 , and a BLE antenna  38  are arranged on a common board  39 . 
     Incidentally, the host OF control portion  31 , the BLE baseband portion  32 , the RF control portion  33 , and the RF switch  34  are formed as a single IC chip in which each function is integrated. 
     The host I/F control portion  31  performs input and output of data with the control portion  300  (see  FIG. 3 ) via a wired interface. An example of the interface is one which is possible to connect to the cable  5   a  (see part (b) of  FIG. 2 ) corresponding to a serial communication system such as a “USB (Universal Serial Bus)”. 
     The BLE baseband portion  32  performs a baseband signal processing in order to perform a digital signal processing by BLE communication. 
     The RF control portion  33  performs a modulation and a demodulation of a radio wave for RF (Radio Frequency) communication in a case of performing BLE communication with the communication terminal  53 . 
     The RF switch  34  performs a switching control to connect to the RF control portion  33  by switching each of the BLE antennas which are the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38 . Here, a switch for switching the RF switch  34  includes four contacts which are a contact a, a contact b, a contact c, and a contact d. 
     The BLE antenna  35  is an antenna which is formed for a wireless communication with the communication terminal  53 . Incidentally, the BLE antenna  35  is a pattern antenna which is wired on the board  39  of the BLE communication unit  5 , and its antenna characteristic is adjusted to perform the BLE communication on the 2.4 GHz band. 
     The BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  are antennas formed in a same way as the BLE antenna  35 . The BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  are adjusted to obtain antenna characteristics which are equivalent to the BLE antenna  35 , and these four BLE antennas with equivalent characteristics are uniformly arranged on the board  39 . 
     The BLE antenna  35  is connected to the contact a of the RF switch  34 , and similarly, the BLE antenna  36 , the BLE antenna  37 , the BLE antenna  38  are connected to the contact b, the contact c, and the contact d of the RF switch  34 , respectively. 
     That is, it is possible to switch which BLE antenna of the four BLE antennas of the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38 , is connected to the RF control portion  33  by the RF switch  34 . 
       FIG. 5  shows a physical form of the BLE communication unit  5 . On the board  39  of the BLE communication unit  5 , the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  are formed so as to be arranged side by side in a plane of the board by a pattern wiring. 
     An IC chip  41  includes a BLE communication function, and as described above, realizes each of functions of the host I/F control portion  31 , the BLE baseband portion  32 , the RF control portion  33 , and the RF switch  34  (see  FIG. 4 ). 
     The BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  are connected to the IC chip  41 , and are electrically connected to the contact a, the contact b, the contact c, and the contact d of the RF switch  34 , respectively, as described above. 
     Further, on the board  39  of the BLE communication unit  5 , a connector  42 , which is possible to connect to the cable  5   a  (see part (b) of  FIG. 2 ) to make an interface connection with the control portion  300 , is provided. Further, a screw hole  43  is provided on the board  39  of the BLE communication unit  5 . The screw hole  43  is conducted to ground of an electric circuit on the board  39 . 
     In general, it is possible to perform maximum antenna characteristics by obtaining electrically stable ground, for a wireless communication board which uses a radio wave in high frequency bands such as BLE. Consequently, in the embodiment, the board  39  is constituted to be grounded by screwing through the screw hole  43  to a metal plate  61  (will be described below) which constitutes a part of a main frame which constitutes a support frame which supports each unit of the image forming apparatus  50  which is an electrically stable ground. Further, a through hole  44  is provided on the board  39  of the BLE communication unit  5 . The through hole  44  is provided in order to determine a position of the BLE communication unit  5  and fix it. 
     As described above using  FIG. 4  and  FIG. 5 , in the embodiment, the BLE communication unit  5  are provided and arranged with the four antennas of the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38 . This is for a direction detection according to Bluetooth standard. 
     Then, by using  FIG. 6 , an overview of a direction detection method by using a plurality of antennas in Bluetooth standard. Part (a) of  FIG. 6  is a method, in which a wireless radio wave of the BLE communication is sent out from a transmitting side with a single antenna, the wireless radio wave is received at a receiving side with a plurality of antennas, and the direction is detected. 
     As described above, in the embodiment, the BLE communication unit  5  of the image forming apparatus  50  is provided and arranged with a plurality of antennas, and in this method, the transmitting side corresponds to the communication terminal  53  and the receiving side corresponds to the image forming apparatus  50 . 
     In part (a) of  FIG. 6 , the wireless radio wave of the BLE communication which is sent out from the single antenna on the transmitting side reaches the receiving side. On the receiving side, by targeting two antennas of an antenna  1  and an antenna  2 , a distance until the wireless radio wave sent out from the transmitting side reaches the antenna  1  is different from a distance until it reaches the antenna  2 . Thus, a phase difference is occurred between the wireless radio wave arriving at the antenna  1  and the wireless radio wave arriving at the antenna  2 . 
     Here, a distance between the antenna  1  and the antenna  2  is defined as d, an arrival angle of the wireless radio wave which arrives at the antenna  1  and the antenna  2  is defined as  01 , and a wavelength of the wireless radio wave is defined as λ. 
     When the phase difference described above is defined as Ψ in this case, a following relationship is established 
       Ψ=(2π d* cos(θ1))/λ
 
     Thus, the arrival angle of the radio wave is as described below. 
       θ 1 =arccos((Ψλ)/(2π d ))
 
     That is, according to the above, it is possible to determine the arrival angle of the radio wave which is arrived at the receiving side by using two antennas of the antenna  1  and the antenna  2  in the receiving side. In this way, it is possible to detect the arrival direction of the radio wave. Incidentally, according to the above, since the wireless radio wave arriving at the antenna  1  and the antenna  2  is used to determine the phase difference, it is necessary that the antenna  1  and the antenna  2  are provided with equivalent radio wave characteristics. 
     Further, it is necessary that the radio wave received by the antenna  1  and the antenna  2  is a direct wave which is sent out from the transmitting side and arrived at the receiving side in a straight line along a same propagation route. In the embodiment, four antennas of the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38 , are arranged with the BLE communication unit  5  of the image forming apparatus  50  in the receiving side. 
     As described above in  FIG. 4 , the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  possess equivalent radio wave characteristics. While these BLE antennas are switched by the RF switch  34 , the arrival angle of the wireless radio wave is calculated by the wireless radio wave which is received by targeting the two BLE antennas, as described above. 
     Thus, it is possible for the image forming apparatus  50  to detect a direction toward the communication terminal  53  as an arrival angle θ 1  (arrival direction) of the wireless radio wave by the BLE communication unit  5 . 
     Part (b) of  FIG. 6  shows a method in which a transmitting side with a plurality of antennas send out the wireless radio wave of the BLE communication and a receiving side with a single antenna receives it and detects the direction. 
     As described above, in the embodiment, the BLE communication unit  5  of the image forming apparatus  50  is provided and arranged with a plurality of antennas, and in this method, the receiving side corresponds to the communication terminal  53  and the transmitting side corresponds to the image forming apparatus  50 . 
     In part (b) of  FIG. 6 , the wireless radio wave of the BLE communication which is sent out from the antenna of the transmitting side reaches the receiving side. Here, on the transmitting side, the antenna  1  and the antenna  2  are switched sequentially and send out the wireless radio wave sequentially. 
     Thus, by targeting two antennas of the antenna  1  and the antenna  2 , a distance until the wireless radio wave sent out from the antenna  1  of the transmitting side reaches the receiving side is different from a distance until the wireless radio wave sent out from the antenna  2  of the transmitting side reaches the receiving side. Thus, a phase difference is occurred between the wireless radio wave in which the receiving side receives from the antenna  1  and the wireless radio wave in which the receiving side receives from the antenna  2 . 
     Here, the distance between the antenna  1  and the antenna  2  is defined as d, a sending angle of the wireless radio wave which sends out from the antenna  1  and the antenna  2  is defined as θ 2 , and the wavelength of the wireless radio wave is defined as λ. When the phase difference described above is defined as Ψ in this case, a following relationship is established. 
       Ψ=(2π d* cos(θ2)/λ
 
     Thus, the sending angle of the radio wave is as described below. 
       θ2=arccos((Ψλ)/(2π d ))
 
     That is, according to the above, it is possible to determine the sending angle of the wireless radio wave of the transmitting side by using two antennas of the antenna  1  and the antenna  2  in the transmitting side and receiving it at the single antenna in the receiving side. 
     Incidentally, according to the above, since the wireless radio wave which is sent out from the antenna  1  and the antenna  2  is used to determine the phase difference, it is necessary that the antenna  1  and the antenna  2  are provided with equivalent radio wave characteristics. Further, it is necessary that the radio wave is sent out from the antenna  1  and the antenna  2  and is a direct wave which arrives at the single antenna in the receiving side in a straight line along a same propagation route. 
     In the embodiment, the four antennas of the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38 , are arranged with the BLE communication unit  5  of the image forming apparatus  50  in the transmitting side. As described above, the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  possess equivalent radio wave characteristics. While these BLE antennas are switched by the RF switch  34 , they send out the wireless radio wave. 
     On the other hand, the communication terminal  53  of the receiving side receives this and calculates the sending angle of the wireless radio wave by targeting a wireless radio wave signal which is sent out from the two BLE antennas. Thus, in order to calculate the sending angle of the radio wave described above, it is necessary for the communication terminal  53  to obtain the distance d between the antenna  1  and the antenna  2  in the transmitting side and the wavelength λ of the wireless radio wave from the image forming apparatus  50  of the transmitting side in advance. 
     In the embodiment, information of the distance d and the wavelength is transmitted, in advance, from the image forming apparatus  50  to the communication terminal  53  by BLE communication. Further, the sending angle of the wireless radio wave calculated by the communication terminal  53  is transmitted to the image forming apparatus  50  by BLE communication after the calculation. 
     Thus, it is possible for the image forming apparatus  50  to detect the direction toward the terminal device  53  as the sending angle θ 2  (arrival direction) of the wireless radio wave. In this way, by a method shown in  FIG. 6 , the image forming apparatus  50  is able to detect the arrival direction of the radio wave by the BLE communication unit  5 , so it is possible to recognize a position of a user who carries the communication terminal  53  in coordinates. 
     In the embodiment, as described above in part (a) of  FIG. 2 , the BLE communication unit  5  is arranged on a front portion of the image forming apparatus  50  and in the feeding portion  50   b   1  which is above the main assembly  50   a  in a vertical direction. 
     Here, a method of fixing and arranging of the BLE communication unit  5  in the feeding portion  50   b   1  of the reading device  50   b  will be described by using  FIG. 7 . Part (a) of  FIG. 7  is a view of the BLE communication unit  5 , which is fixed to the feeding portion  50   b   1  of the reading device  50   b,  from a front side of the image forming apparatus  50  (side on which the operation portion  400  is arranged) and a view of the BLE communication unit  5  from a thickness direction of the board. Thus, a transverse direction in part (a) of  FIG. 7  is a horizontal direction in which the image forming apparatus  50  is installed. Further, part (b) of  FIG. 7  is a view of it from a top of the image forming apparatus  50 . 
     The metal plate  61  is a part of a frame plate which constitutes the support frame of the reading device  50   b  as described above, and a part of the frame plate which constitutes the support frame of the feeding portion  50   b   1 . Here, the metal plate  61  may be a plate which is integrally constituted with a plate which supports each unit of the feeding portion  50   b   1 , or it may be a plate which is constituted of a separate body. 
     The metal plate  61  serves as a frame ground for an electric circuit in the reading device  50   b,  and is grounded via a ground wire, etc. 
     A metal spacer  62  is constituted of a metal member which is formed of metal, is a spacer for fixing the BLE communication unit  5  to the metal plate  61  and is fixed to the metal plate  61 . 
     A resin spacer  64  is constituted of a resin member which is formed of plastic resin, is a spacer for fixing the BLE communication unit  5  to the metal plate  61  and is fixed to the metal plate  61 . 
     A screw  63  is a metal screw for fixing the BLE communication unit  5  to the metal spacer  62 , and fixes the BLE communication unit  5  by passing through the screw hole which is provided with the BLE communication unit  5  and being tighten by a tap which is formed in the metal spacer  62 . As described above, the screw hole  43  which is provided with the BLE communication unit  5  is grounded to an electric circuit of the BLE communication unit  5 . 
     Thus, ground of the electric circuit of the BLE communication unit  5  is connected to the metal plate  61  through the metal spacer  62  and the screw  63 , that is, it is connected to the frame ground of the electric circuit of the reading device  50   b.    
     The resin spacer  64  is formed so that its tip portion penetrates the through hole  44  of the BLE communication unit  5 . Thus, the resin spacer  64  prevents the BLE communication unit  5  from rotating around the metal spacer  62 , when the BLE communication unit  5  is fixed to the metal plate  61 . 
     The outer cover  65  is an outer part which covers an outer surface of the reading device  50   b  and an outer surface of the feeding device  50   b,  and is formed by plastic resin. The outer cover  65  is arranged to cover a front of the BLE communication unit  5  opposing the feeding portion  50   b   1 . Thus, the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  of the BLE communication unit  5  are covered by the outer cover  65 . Here, the outer cover  65  is an example of a cover member which covers the BLE communication unit  5  which is fixed to the metal plate  61 . 
     As described above in part (a) of  FIG. 7 , the BLE communication unit  5  is fixed to the metal plate  61  via the metal spacer  62  and the resin spacer  64 . In this case, the respective antennas of the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  of the BLE communication unit  5  are arranged and fixed to the metal plate  61  so that they are arrayed in a horizontal direction on an installation surface of the image forming apparatus  5 . Here, the metal spacer  62  is an example of a first support member, and the resin spacer  64  is an example of a second support member. 
     This is, as described above using part (a) of  FIG. 6  and part (b) of  FIG. 6 , due to detect the arrival angle and the sending angle of the wireless radio wave by using two of the antennas when performing a direction detection between the image forming apparatus  50  and the communication terminal  53 . 
     That is, in a case of performing a direction detection between the image forming apparatus  50  and the communication terminal  53  which is present on a horizontal plane of an installation of the image forming apparatus  50 , it is possible to detect in all directions efficiently by arraying the respective BLE antennas in a horizontal direction. 
     Incidentally, as shown in part (b) of  FIG. 7 , the BLE communication unit  5  is fixed to the metal plate  61  by the metal spacer  62  and the resin spacer  64  with the distance e, so that it is parallel to the metal plate  61 . At this time, the BLE communication unit  5  is fixed to the metal plate  61  so that distances between each of the BLE antennas from  35  to  38  and the metal plate  61  are equally spaced. 
     This is due to maintain a uniform distance between each of the BLE antennas from  35  to  38  which are formed on the BLE communication unit  5  and the metal plate  61 , and prevent the metal plate  61  from causing differences in the antenna characteristics of the BLE antennas from  35  to  38 . 
     In this way, it is possible to send and receive the wireless radio wave under a same characteristic conditions of the respective antennas, and it is possible to correctly detect a phase difference of the wireless radio waves between antennas in the direction detection by the wireless radio wave described above, and to accurately calculate a direction in which the communication terminal  53  as a communication target is located. 
       FIG. 8  is a view showing the outer cover  65 . As shown in part (a) of FIG.  2 , the outer cover  65  is an outer part which is mounted on a front side in the feeding portion  50   b   1  and covers the BLE communication unit  5 . Further, the outer cover  65  is an outer part which is mounted on a front of the reading device  50   b  which is located above the main assembly  50   a,  and fixed to the support frame of the feeding portion  50   b   1  of the reading device  50   b  by unshown screws, etc. 
     Part (a) of  FIG. 8( a )  is a perspective view of the outer cover  65  viewed from an inner surface  65   a  side. Part (b) of  FIG. 8  is a plan view showing a detailed constitution of the inner surface  65   a  of the outer cover  65 . Here, in the outer cover  65 , a surface, which is inside the image forming apparatus  50  and faces toward an inside of the reading device  50   b  while the outer cover  65  is mounted on the reading device  50   b,  is defined as the inner surface  65   a.  Further, in the outer cover  65 , a surface, which is inside the imaging forming apparatus  50  and opposes the support frame (the metal plate  61  and the BLE communication unit  5 ) while the outer cover  65  is mounted on the reading device  50   b,  is defined as the inner surface  65   a.  And, in the outer cover  65 , a surface which forms an outer appearance of the image forming apparatus  50  is defined as the outer surface  65   b.    
     Here, the outer cover  65  is molded from resin. In general, in a cover member, which is formed using a resin material, ribs, bosses, etc. are formed on the inner surface  65   a  in order to ensure a strength. 
     In the outer cover  65  of the embodiment, as shown in part (b) of  FIG. 8 , a plurality of ribs  66  as reinforcing ribs and a plurality of bosses  67  are formed on the inner surface  65   a.  In this way, the cover itself is prevented from being deformed by reinforcing it with the ribs  66  and the bosses  67 . Incidentally, in the embodiment, a constitution, which includes both ribs  66  and bosses  67 , is shown, however, the outer cover  65  may be reinforced by either ones. 
     However, even on the inner surface  65   a  of the outer cover  65 , an area  68  includes a uniform surface where ribs  66  and bosses  67  are not formed. That is, since the ribs  66  and the bosses  67  are provided in an area other than the area  68 , a constitution of the area  68  is less unevenness compared to other area on the inner surface  65   a  of the outer cover  65 . 
     In part (a) of  FIG. 2 , the area  68  is arranged at a position to cover an area where the BLE communication unit  5  is arranged when the outer cover  65  is mounted on the reading device  50   b.  That is, the area  68  is an area which opposes the BLE communication unit  5  on the inner surface  65   a  of the outer cover  65 , and an area which opposes the BLE antennas from  35  to  38 . 
     Further, as shown in part (b) of  FIG. 7 , the area  68  of the outer cover  65  which covers the BLE communication unit  5  is molded so that a thickness f of a molding material is uniform. 
     That is, no ribs and bosses are existed in a portion of the area  68  of the outer cover  65  which covers the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  of the BLE communication unit  5 , and the portion of the area  68  is made by molding resin so that the thickness f is uniform. 
     This is due to maintain uniform radio wave characteristics of a member which is arranged in front of the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  of the BLE communication unit  5 . 
     That is, this is due to avoid causing a difference in characteristics of the wireless radio waves which are passed through the outer cover  65  and are sent and received by the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38 , so that it is possible to send and receive the wireless radio waves under same characteristic conditions for the respective antennas. 
     In this way, it is possible to correctly detect a phase difference of the wireless radio waves between the antennas and to accurately calculate a direction in which the communication terminal  53  is positioned, in the direction detection of the communication terminal  53  by using the wireless radio waves, 
     In the embodiment described above, the BLE communication unit  5  is constituted that the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  are pattern antennas which are formed by board patterns on the board  39  of the BLE communication unit  5 . However, a main purpose of the embodiment is to arrange the BLE communication unit  5  which includes a plurality of antennas in a position on a front side of the image forming apparatus  50 . 
     Thus, these antennas may be arranged by mounting antenna parts with equivalent characteristics (generally known chip antenna) on the board  39 . Further, these antennas are not necessarily arranged on the board  39 , and the plurality of antennas may be fixed and arranged by providing terminal connectors at antenna terminals a, b, c, and d of the IC chip  41 , and connecting to external antennas with coaxial cables, etc. 
     Further, in the embodiment, the four antennas of the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  are provided. 
     However, as shown in  FIG. 6 , when two or more antennas are provided, it is possible to detect a direction by switching them, and a number of antennas may be changed as appropriate, as long as two or more, depending on a required accuracy of a direction detection, a required detection speed, etc. 
     Based on the description so far, a method, how to identify a user&#39;s movement locus by detecting a direction between the image forming apparatus  50  and the communication terminal  53 , will be described below. 
     Incidentally, in the description above, a direction detection method in which the communication terminal  53  is the transmitting side and the image forming apparatus  50  is the receiving side was described by part (a) of  FIG. 6 , and a direction detection method in which the communication terminal  53  is the receiving side and the image forming apparatus  50  is the transmitting side was described by part (b) of  FIG. 6 . 
     Regardless of which of these methods is used, the imaging forming apparatus  50  is able to detect a direction of the communication terminal  53  by using the BLE communication unit  5 , as described above. 
     Thus, in a description below, the image forming apparatus  50  shall use one of the methods described above to perform a direction detection of the mobile communication terminal  53 . 
     Part (a) of  FIG. 9  shows an example when a user who carries a communication terminal  53  is moving near a front of the image forming apparatus  50 . In the description below, a distance between the imaging forming apparatus  50  and the communication terminal  53  shall be detected based on a radio wave strength which is detected by at least one of the plural antennas of the BLE communication unit  5  as a conventionally used method. 
     First, a position of the communication terminal  53  with respect to the image forming apparatus  50  when the user is at a position A is detected as in a direction of angle α by the image forming apparatus  50 . In addition, a distance at that time is detected as a distance p. 
     After that, in a case that the user moves closer towards the image forming apparatus  50  and moves to a position B, a position of the communication terminal  53  with respect to the image forming apparatus  50  is detected as in a direction of an angle α. In addition, a distance at that time is a distance q. 
     That is, in a case that the user who carries the communication terminal  53  moves from the position A to the position B toward the image forming apparatus  50  and comes close to it, an angle at which the communication terminal  53  is positioned with respect to the image forming apparatus  50  remains the angle α, and the distance from the communication terminal  53  to the image forming apparatus  50  approaches from the distance p to the distance q. 
     On the other hand, part (b) of  FIG. 9  shows another example when the user who carries the communication terminal  53  is moving near a front of the image forming apparatus  50 . 
     First, a position of the communication terminal  53  when the user is at the position A is detected as in the direction of the angle α with respect to the image forming apparatus  50 . In addition, the distance at that time is detected as the distance p. 
     After that, in a case that the user moves to a position C in a horizontal direction in front of the image forming apparatus  50 , a position of the communication terminal  53  with respect to the image forming apparatus  50  is detected as in a direction of an angle β. In addition, a distance at that time is detected as a distance r. 
     That is, in a case that the user who carries the communication terminal  53  is not approaching the image forming apparatus  50 , the angle at which the communication terminal  53  is positioned with respect to the image forming apparatus  50  changes arbitrarily from the angle α to the angle β, and the distance from the communication terminal  53  to the image forming apparatus  50  changes arbitrarily from the distance p to the distance q. 
     Thus, by detecting the angle which indicates the direction of the communication terminal  53  and the distance to the communication terminal  53  and by detecting the movement locus, the image forming apparatus  50  is able to identify whether the user who carries the communication terminal  53  is approaching to operate the image forming apparatus  50  or passing through a vicinity of the image forming apparatus  50 . 
     Incidentally, in  FIG. 9 , the example, in which the user who carries the communication terminal  53  is moving near the front of the image forming apparatus  50 , is illustrated, however, as long as the user is within a communication area of the BLE communication unit  5 , it is also possible to detect the user who is approaching the image forming apparatus  50  from a side of it. 
     Next, an operation of returning the image forming apparatus  50  from a sleep state to a standby state, by detecting a movement locus of the user who carries the communication terminal  53  as described in part (a) of  FIG. 9  and part (b) of  FIG. 9 , will be described using the flow chart in  FIG. 10 . Here, the standby state is a state in which the image forming apparatus  50  is started up and is ready to form an image on a sheet by accepting an image forming job. Further, the standby state is a state in which the reading device  50   b  of the image forming apparatus  50  is able to read a current image by accepting an instruction from the user. Further, the sleep state is a power saving state which consumes less power than the standby state, is a state to which a predetermined power source voltage is applied, and is a state which is able to shift to the standby state by performing a return operation. 
     In S 1001 , the control portion  300  determines whether or not the communication terminal  53  is detected by the BLE communication unit  5 . Here, by using a method described in  FIG. 6 , the communication terminal  53  is detected based on that the BLE communication unit  5  receives the radio wave. 
     Then, in a case that the communication terminal  53  is detected (S 1001  YES), go to S 1002 . In S 1002 , a direction of the communication terminal  53  which is detected in S 1001  is detected by using a method described in  FIG. 9 , and whether the direction is constant or not is determined by detecting a change in an angle in which the communication terminal  53  is positioned. That is, in S 1002 , by detecting a position of the communication terminal  53  every predetermined time, it detects whether an angle of the communication terminal  53  with respect to the image forming apparatus  50  is constant or changed. 
     In a case that the direction is constant (S 1002  YES), go to S 1003 . In a case that the direction is not constant (S 1002  NO), go to S 1001 . 
     In S 1003 , the control portion  300  detects a distance from the communication terminal  53  by the BLE communication unit  5  and determines whether or not the distance is within a predetermined distance. That is, in S 1003 , the control portion  300  determines whether or not the communication terminal  53  approaches the image forming apparatus  50  within a certain distance. 
     In a case that the distance from the communication terminal  53  is within the predetermined distance (S 1003  YES), go to S 1004 . In a case that the distance from the communication terminal  53  is not within the predetermined distance (S 1003  NO), go to S 1001 . 
     In S 1004 , the control portion  300  performs a sleep return process to return each portion of the image forming apparatus  50  from the sleep state to the standby state. 
     Specifically, the control portion  300  displays an operation screen, which is necessary for a user operation, on the display portion  410  by the display control portion  304  as the sleep return process. That is, the control portion  300  controls a transition of the display screen of the display portion  410  to a screen of a startup state or controls the display of the display portion  410  to turn on, as the sleep return process. Further, the control portion  300  performs startup control on each portion of the main assembly  50   a  and the document reading device  50   b  which are in the sleep state, as the sleep return process, and returns to a state in which various functions are operable. Here, the startup control of each portion is a control which performs warm up operations for performing an image forming operation and a reading operation, such as a startup control of motors, etc., a temperature control of the fixing device, etc. 
     In this way, in  FIG. 10 , it is possible to perform the sleep return process only when the user is approaching toward the image forming apparatus  50 , after identifying accurately the user approaching to operate the image forming apparatus  50  and the user passing through the image forming apparatus  50  by detecting a direction and a distance in which the communication terminal  53  is positioned. 
     Incidentally, the sleep return process may be performed without a step of S 1003 , by determining that the user is approaching the image forming apparatus  50  based on a fact that positions of the communication terminals  53  are approaching from a same direction. This also allows the sleep return process to be performed only when the user approaches to operate the image forming apparatus  50 . 
     Thus, the image forming apparatus  50  is able to save even more power by avoiding an unnecessary sleep return. Further, since the direction and the distance of the user approaching to operate the image forming apparatus  50  are detected using the BLE communication unit  5 , it is possible to more accurately control a timing of the sleep return based on the user&#39;s position. Thus, the image forming apparatus  50  is able to provide the sleep return which is fast and stress free according to the user&#39;s movement and improve a usability. 
     Incidentally, as for whether a direction determined in S 1002  is constant or not, a direction may be determined as a constant in a case that the angle is completely same angle, however, or it may be also determined as a constant direction in a case that a change in angle is within a predetermined range. For example, it may be determined as a constant direction in a case that the change in angle is within plus and minus 20 degrees. 
     Next, an operation, in which the image forming apparatus  50  performs a user authentication by a method of identifying the movement locus of the user who carries the communication terminal  53  as described in part (a) of  FIG. 9  and part (b) of  FIG. 9 , will be described by using the flow chart in  FIG. 11 . 
     In S 1101 , the control portion  300  determines whether or not the communication terminal  53  is detected by the BLE communication unit  5 . Here, by using the method described in  FIG. 6 , the communication terminal  53  is detected based on a fact that the BLE communication unit  5  receives the radio wave. 
     Then, in a case of detecting the communication terminal  53  (S 1101  YES), go to S 1102 . In S 1102 , by detecting a direction in which the communication terminal  53  detected in S 1101  is positioned and detecting a change in the angle in which the communication terminal  53  is positioned, it is determined whether the direction is constant or not. That is, in S 1102 , by detecting a position of the communication terminal  53  every predetermined time, it detects whether the angle of the communication terminal  53  with respect to the image forming apparatus  50  is constant or the angle is changed. 
     In a case that the direction is constant (S 1102  YES), go to S 1103 . In a case that the direction is not constant (S 1102  NO), go to S 1101 . 
     In S 1103 , the BLE communication unit  5  detects a distance from the communication terminal  53  and the control portion  300  determines whether or not the distance is within a predetermined distance. That is, in S 1103 , the control portion  300  determines whether the communication terminal  53  is close to the image forming apparatus  50  within a certain distance. 
     In a case that the distance from the communication terminal  53  is within the predetermined distance (S 1103  YES), go to S 1104 . In a case that the distance from the communication terminal  53  is not within the predetermined distance, go to S 1101 . 
     In S 1104 , the control portion  300  performs the user authentication process through the BLE communication with the communication terminal  53  by the BLE communication unit  5 . 
     Here, user IDs associated with users are registered in the communication terminal  53 , and, further, an ID list of the users who can be authenticated is stored in the memory device  303  of the image forming apparatus  50 . 
     That is, the control portion  300  obtains the user ID associated with the communication terminal  53  through the BLE communication with the communication terminal  53 , checks it against the ID list of the users who can be authenticated by the memory device  303 , and performs the user authentication based on whether or not the ID list matches the obtained user ID. 
     And, in S 1105 , the control portion  300  determines whether or not the mobile terminal  53  is authenticated by the user authentication process in S 1104 . 
     In a case of being authenticated (S 1105  YES), go to S 1106 . In a case of not being authenticated, go to S 1101 . 
     In S 1106 , the control portion  300  performs a log in process for the authenticated user. Specifically, the control portion  300  displays an operation screen which is necessary for a user operation on the display unit  410  by the display control portion  304 . In this case, the control portion  300  reads various settings of the authenticated user, which are stored in the memory device  303 , and displays a standby operation screen which is customized for the user on the display portion  410 . Thus, the authenticated user is able to log in to the imaging forming apparatus  50  and easily operate the imaging forming apparatus  50 . 
     In  FIG. 11 , by detecting the direction and the distance in which the communication terminal  53  is positioned, it is possible to accurately identify a user who approaches in order to operate the image forming apparatus  50  and a user who passes through the image forming apparatus  50  and performs the log in process only in the case of approaching toward the image forming apparatus  50 . 
     Incidentally, it may be constituted to perform the user authentication process without a step of S 1103 , by determining that a user is approaching the image forming apparatus  50  based on a fact that positions of the communication terminal  53  are approaching from a same direction. In this way, it is also possible to perform the log in process only in the case that the user approaches in order to operate the image forming apparatus  50 . 
     Thus, it is possible to suppress the unnecessary authentication and the unnecessary log in process for a user who passes through the image forming apparatus  50 . Further, since it is possible to detect the direction and the distance of the user who approaches in order to operate the image forming apparatus  50 , it is possible to control a timing of the authentication process by the user&#39;s position more appropriately. Thus, by performing the authentication process and the log in process in accordance with the user&#39;s arrival in the image forming apparatus  50 , it is possible to improve usability since it is possible to perform the authentication process and the log in process in a way that is fast and stress free for the user. 
     Incidentally, in the embodiment described above, an example, in which the sleep return process and the user log in process are performed respectively by detecting the direction and the distance in which the communication terminal  53  is positioned, is described, however, both the sleep return process and the log in process may be performed. For example, it may be constituted to perform the sleep return process and the user authentication process when a distance between the communication terminal  53  which approaches from a same direction and the image forming apparatus  50  is a predetermined distance. 
     Further, as for whether or not the direction determined in S 1102  is constant, the direction may be determined to be constant in a case that an angle is completely same, however, the direction may also be determined to be constant in a case that a change of an angle is within a predetermined range. For example, in a case that a change in an angle is within plus and minus 20 degrees, it may be determined to be a constant direction. 
     Further, in the embodiment described above, an example, that only one communication terminal  53  approaches, is described, however, in a case that a plurality of the communication terminals  53  are detected within the communication area of the BLE communication unit  5 , the directions and the distances of positions of respective terminals  53  may be detected respectively based on data of the terminals  53 . In this case, in a case that any one of the plurality of the communication terminals  53  approaches from a same direction for a predetermined distance, it may perform the sleep return process and the user authentication process for the communication terminal  53  which approaches from the same direction for the predetermined distance. Incidentally, in a case that two or more communication terminals, out of a plurality of the communication terminals  53  positioned within the communication area of the BLE communication unit  5 , are detected approaching from a same direction, the user authentication process may be constituted to be performed with a communication terminal  53  which approaches in a predetermined distance first. Incidentally, as long as a control is based on the direction and the distance in which the communication terminal is positioned using the plurality of the BLE antennas from  35  to  38 , it may be constituted to perform other controls than the sleep return process and the user authentication process. In this way, by mounting the plurality of the BLE antennas from  35  to  38  on the image forming apparatus  50 , it is possible to improve a performance of the image forming apparatus  50 . 
     As described above, in the embodiment, the BLE communication unit  5  is arranged on a front side of the image forming apparatus  50 . Thus, when the BLE communication is performed with the communication terminal  53  which is owned by the user, it is possible to prevent radio waves from being shielded by the main assembly  50   a,  the reading device  50   b,  etc. of the image forming apparatus  50  and to detect a direction in which the communication terminal  53  is positioned by using the BLE communication. Further, by arranging the BLE communication unit  5  in a vicinity of the operation portion  400 , it is possible to more accurately detect the user who carries the communication terminal  53  and approaches the image forming apparatus  50  to operate the operation portion  400 . 
     Further, the BLE communication unit  5  is arranged in the vicinity the operation portion  400 , above the main assembly  50   a  in a vertical direction, and at a relatively high position in the image forming apparatus  50 . Further, the BLE communication unit  5  is arranged above the discharge tray  92  in a vertical direction, above the discharging roller pair  91 , and at a relatively high position in the image forming apparatus  50 . Thus, it is possible to send and receive the direct wave of the wireless radio wave which arrives by avoiding an influence of obstacles between the image forming apparatus  50  and the communication terminal  53 , with sufficient radio wave strength. Thus, it is possible to detect efficiently the direction in which the communication terminal  53  is positioned. 
     Further, in the embodiment described above, a sensor is provided to detect that the feeding portion  50   b   1  is open with respect to the reading portion  50   b   2 , and, in a case that the feeding portion  50   b   1  is in an open state as a result of a sensor detection, the BLE communication unit  5  may be constituted not to detect the communication terminal  53 . That is, the detection of the communication terminal  53  by the BLE communication unit  5  may be constituted to be performed only in a case that the feeding portion  50   b   1  is in a closed state. 
     According to this constitution, it is possible to prevent an inability of a favorable detection of the arrival radio wave, due to inconsistency at all times of a detection range by the BLE antennas from  35  to  38  by a rotational angle of the feeding portion  50   b   1 , an attachment error in the closed state, etc. Thus, it is possible to prevent a decrease in an accuracy of detection of the position and the direction of the communication terminal  53  due to a change in a detection direction of the BLE antennas from  35  to  38  by an angle of the open state of the feeding portion  50   b   1 . Therefore, it is possible to send and receive the direct wave of the arrival wireless radio wave with a sufficient radio wave strength by avoiding an influence of an obstacle existing between the image forming apparatus  50  and the communication terminal  53 . Thus, it is possible to favorably detect the direction in which the communication terminal  53  is positioned. 
     Embodiment 2 
     Next, a second embodiment will be described using  FIG. 12 .  FIG. 12  is an external appearance perspective view of the image forming apparatus  50  showing the second embodiment. Incidentally, in the other embodiments, an only difference from the embodiment shown in  FIG. 2  is an arrangement of the BLE communication unit  5 , and similar constitutions are indicated with same reference numerals and omitted from descriptions. Incidentally, in  FIG. 12 , the board  39  and the BLE antennas from  35  to  38  which constitute the BLE communication unit  5  are not shown, however, its constitution is same as in the first embodiment described above. 
     In an embodiment shown in  FIG. 12 , as the other examples of arranging the BLE communication unit  5  above the discharging roller pair  91  of the image forming apparatus  50  in a vertical direction, BLE communication units  5   x  and  5   y  are shown. 
     The BLE communication unit  5   x  is arranged in a front side of the reading portion  50   b   2  of the reading device  50   b  which is above the main assembly  50   a.    
     Further, the BLE communication unit  5   x  is fixed to the unshown metal plate  61  as the support frame of the reading portion  50   b   1  of the reading device  50   b.  And the board  39 , on which the BLE antennas from  35  to  38  are mounted, is covered by an outer cover  65   x  which forms an outer in a front side of the reading portion  50   b   1 . In this case, similar to a constitution shown in  FIG. 8 , an area  68   x,  which is an area opposing the BLE antennas from  35  to  38  and opposing the BLE communication unit  5   x,  is formed with a uniform thickness without any ribs or bosses. Thus, as same in the embodiment described above, it is possible to send and receive the wireless radio waves at the respective antennas under same characteristic conditions, preventing from causing differences in characteristics of the wireless radio waves which are sent and received by the BLE antennas from  35  to  38 . Thus, it is possible to accurately calculate the direction in which the communication terminal  53  is positioned by correctly detecting the phase differences of the wireless radio waves among the antennas in the direction detection of the communication terminal  53  by means of the wireless radio waves. 
     In this way, the BLE communication unit  5   x  is constituted to be arranged in a position in the front side of the image forming apparatus  50 , above the discharging roller pair  91  in a vertical direction, and above the main assembly  50   a  in a vertical direction. Thus, it is possible to prevent from being shielded by the main assembly  50   a  and the reading device  50   b  etc. of the image forming apparatus  50 , and to favorably detect a direction in which the communication terminal  53  is positioned by using the BLE communication. Further, it is possible to detect a user more accurately, who carries the communication terminal  53  and approaches the image forming apparatus  50  in order to operate the operation portion  400 , by arranging the BLE communication unit  5  in a vicinity of the operation position  400 . 
     Further, at a position of the BLE communication unit  5   x,  it is not fixed to the rotatable feeding portion  50   b   1 , but is fixed to the immovable reading device  50   b   2 . That is, in an arrangement of the BLE communication unit  5   x,  the BLE communication unit  5   x  is immovable. Thus, it is possible to prevent an inability of a favorable detection of the arrival radio wave due to inconsistency at all times of the detection range by the BLE antennas from  35  to  38 , by the rotational angle of the feeding portion  50   b   1 , the attachment error in the closed state, etc. By this constitution, it is possible to detect more favorably a direction in which the communication terminal  53  is positioned, since it is possible to detect the arrival radio wave favorably. 
     Further, as for another example shown in  FIG. 12 , the BLE communication unit  5   y  may be constituted to be arranged on a front side of the operation portion  400  which is above the main assembly  50   a  in a vertical direction. Here, the front side of the operation portion  400  is a portion which is positioned at forefront side of the image forming apparatus  5  in the operation portion  400 . Further, the front side of the operation portion  400  is a portion which is positioned at front side of the display portion  410  such as a touch panel, etc. with respect to a front and rear direction of the image forming apparatus  50 . 
     And the BLE communication unit  5   y  is fixed to the metal plate  61  which is a part of the unshown support frame which supports the display portion  410 , etc. of the operation portion  400 , and is covered by the outer cover  65 . Here, as the outer cover  65   y  is similar to the constitution shown in  FIG. 8 , an area  68   y,  which opposes the BLE antennas from  35  to  38  in an inside of the cover and opposes the BLE communication unit  5   y,  is formed with a uniform thickness without any ribs, bosses, etc. Thus, as same in the embodiment described above, it is possible to send and receive the wireless radio waves at the respective antennas under same characteristic conditions, preventing from causing differences in characteristics of the wireless radio waves which are sent and received by the BLE antennas from  35  to  38 . 
     Further, in a case that the operation portion  400  is provided with the BLE communication unit  5   y,  since the operation portion  400  is positioned on the front side of the image forming apparatus  50  rather than the reading device  50   b,  it is possible to perform communication with the BLE communication unit  5  on the front side of the image forming apparatus  50 . Thus, it is possible to prevent the radio wave from being shielded by the main assembly  50   a  and the reading device  50   b  of the image forming apparatus  50 , and to detect favorably the direction in which the communication terminal  53  is positioned by using the BLE communication. Further, by arranging the BLE communication unit  5  in the operation portion  400 , it is possible to more accurately detect the user who carries the communication terminal  53  and approaches the image forming apparatus  50  to operate the operation portion  400 . 
     Incidentally, in a case that the BLE communication unit  5   y  is provided with the operation panel  400 , in order to improve a detection accuracy of the arrival radio wave by the plurality of antennas from  35  to  38 , the operation portion  400  should be constituted not to be rotatable with respect to the main assembly  50   a.  Further, in a case that a constitution in which the operation portion  400  does not rotate with respect to the main assembly  50   a  and the display portion such as a touch panel is arranged so that it faces the front side of the image forming apparatus  500 , the front side of the operation portion  400  is a surface in which the display portion is arranged. Thus, in this case, the BLE communication unit may be constituted to be provided on a same surface in which the display portion  400  is provided. 
     Further, it may be constituted to detect a direction in which the communication  53  is positioned, only in a case that it is possible to detect accurately the arrival radio wave by the plurality of antenna from  35  to  38  based on a detection result of a senser by means of the senser which detects a rotational angle with respect to the main assembly  50   a  though the operation portion  400  is constituted to be rotatable. 
     Embodiment 3 
     Next, a third embodiment will be described by using  FIG. 13  and  FIG. 14 .  FIG. 13  is an external appearance view of the image forming apparatus  50  showing the third embodiment. Incidentally, in the embodiment, an only difference from the embodiment described above is an arrangement of the BLE communication unit  5 , and similar constitutions are indicated with same reference numerals and omitted from descriptions. Incidentally, in  FIG. 13 , the board  39  and the BLE antennas from  35  to  38  which constitute the BLE communication unit  5  are not shown, however, its constitution is same as in the first embodiment described above. In the embodiment, the BLE communication unit  5  is arranged on a front portion of the main assembly  50   a  of the image forming apparatus  50  and below the operation portion  400 . Further, the BLE communication unit  5  is covered by the outer cover  65 . That is, the BLE communication unit  5  in the embodiment is provided so that it is positioned on the front side of the image forming portion  500  in a front and rear direction of the image forming apparatus  50 . Further, the BLE communication unit  5  in the embodiment is provided so that it is positioned on the front side of the discharging roller pair  91  in the front and rear direction of the image forming apparatus  50 . Further, the BLE communication unit  5  in the embodiment is provided in the position in which it does not overlap with the operation portion  400  when the image forming apparatus  50  is viewed from the front side, even in the case that the operation portion  400  is rotated with respect to the main assembly  50   a.    
     In many cases, a user who carries the communication terminal  53  approaches from the front side of the image forming apparatus  50  to operate the operation portion  400  of the image forming apparatus  50 . For details, it will be described below, however, in order to detect a direction by the BLE communication of Bluetooth 5.1, it is necessary to send and receive a direct wave of a wireless radio wave which arrives in a straight line between the image forming apparatus  50  and the communication terminal  53  which is carried by the user. 
     In the embodiment, by arranging the BLE communication unit  5  on the front side of the main assembly  50   a  of the image forming apparatus  50 , it is possible to send and receive the direct wave of the wireless radio wave with the sufficient radio wave strength without being affected by shielding of the radio wave by the main assembly of the image forming apparatus  50 , etc., in the BLE communication with the communication terminal  53  which is carried by the user. For example, in a case that the BLE communication unit  5  is arranged on the rear side of the image forming apparatus  50 , it may not be possible to obtain the sufficient radio wave strength since the radio wave is shielded by the unit inside the image forming apparatus  50  or the reading device  50   b.  However, in the embodiment, by arranging the BLE communication unit  5  on the front side of the main assembly  50   a  of the image forming apparatus  50 , it is possible to prevent the radio wave from being shielded by the image forming apparatus  50  itself. Further, by arranging the BLE communication unit  5  in a vicinity of the operation portion  400 , it is possible to more accurately detect the user who carries the communication terminal  53  and approaches the image forming apparatus  50  to operate the operation portion  400 . 
     Further, the BLE communication unit  5  is arranged in the vicinity of the operation portion  400  and below the operation portion  400  in a vertical direction, which is a relatively high position in the main assembly  50   a.  Here, the relatively high position with respect to the main assembly  50   a  is a position above the image forming portion  500  and the front cover  100  in a vertical direction. Further, the relatively high position with respect to the main assembly  50   a  is the position above the discharge tray  92  in the vertical direction. Here, the position above the discharge tray  92  in the vertical direction is a position above at least a part of the sheet loading surface of the discharge tray  92 . Further, the relatively high position with respect to the main assembly  50   a  is a position above the sheet feeding cassette  87  in the vertical direction. In this way, by arranging the BLE communication unit  5  at the relatively high position in the main assembly  50   a,  it is possible to send and receive the direct wave of the wireless radio wave with sufficient radio wave strength, avoiding the influence of obstacles which exist between the image forming apparatus  50  and the communication terminal  53 . Incidentally, details of each constitution and arrangement of the BLE communication unit  5  are similar to the first embodiment, so the descriptions of them will be omitted. 
     In the embodiment, while the BLE communication unit  5  is arranged on a front side of the main assembly  50   a  of the image forming apparatus  50  as shown in part (b) of  FIG. 13 , the control portion  300  is arranged on the rear side of the main assembly  50   a  as shown in parts (b) and (c) of  FIG. 13 . 
     Thus, the BLE communication unit  5  and the control portion  300  are electrically connected by a cable  5 . 
     Since the cable  5   a  is passed through the cable guide  600 , which is provided with the main assembly  50   a,  is wired from a front surface to a rear surface in the main assembly  50   a,  it is easy to wire in the main assembly  50   a  and is designed to enhance workability when the image forming apparatus  50  is assembled or maintained. 
       FIG. 14  is a view showing the outer cover  65 . As shown in part (a) of  FIG. 13 , the outer cover  65  is an outer part which is mounted below the display portion  410  in the main assembly  50   a,  and covers the BLE communication unit  5 . Further, the outer cover  65  is an outer part which is mounted above the front cover  100 , and is fixed to the support frame of the main assembly  50   a  by unshown screws, etc. 
     Part (a) of  FIG. 14  is a perspective view of the outer cover  65  viewed from an inner surface  65   a  side. Part (b) of  FIG. 14  is a plan view showing a detailed constitution of the inner surface  65   a  of the outer cover  65 . Here, in the outer cover  65 , a surface, which is inside the image forming apparatus  50  and faces toward the inside of the main assembly  50   a  while the outer cover  65  is mounted on the main assembly  50   a,  is defined as the inner surface  65   a.  Further, in the outer cover  65 , a surface, which is inside the imaging forming apparatus  50  and opposes the support frame (the metal plate  61  and the BLE communication unit  5 ) while the outer cover  65  is mounted on the main assembly  50   a,  is defined as the inner surface  65   a.  And, in the outer cover  65 , the surface which forms an outer appearance of the image forming apparatus  50  is defined as the outer surface  65   b.    
     Here, the outer cover  65  is molded from resin. In general, in a cover member, which is formed using a resin material, ribs, bosses, etc. are formed on the inner surface  65   a  in order to ensure a strength. 
     In the outer cover  65  of the embodiment, as shown in part (b) of  FIG. 14 , the plurality of ribs  66  as reinforcing ribs and the plurality of bosses  67  are formed on the inner surface  65   a.  In this way, the cover itself is prevented from being deformed by reinforcing the outer cover  65  with the ribs  66  and the bosses  67 . However, even on the inner surface  65   a  of the outer cover  65 , the area  68  includes the uniform surface where the ribs  66  and the bosses  67  are not formed. That is, since the ribs  66  and the bosses  67  are provided in an area other than the area  68 , the area  68  is constituted to be less unevenness compared to the other area on the inner surface  65   a  of the outer cover  65 . 
     The area  68  is arranged at the position to cover the area where the BLE communication portion  5  is arranged when the outer cover  65  is mounted on the main assembly  50   a.  That is, the area  68  is the area which opposes the BLE communication portion  5  on the inner surface  65   a  of the outer cover  65 , and the area which opposes the BLE antennas from  35  to  38 . Incidentally, the arrangement of the BLE communication unit  5  with respect to the area  68  of the outer cover is the same as what is described in the first embodiment by using  FIG. 7 . 
     Further, similar to the first embodiment as shown in part (b) of  FIG. 7 , the area  68  of the outer cover  65  is molded so that the thickness f of the molding material is uniform. Thus, similar to the first embodiment, no ribs and bosses are existed in the portion of the area  68  of the outer cover  65  which covers the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  of the BLE communication unit  5 , and the portion of the area  68  is formed by molding resin so that the thickness f is uniform. 
     Thus, it is possible to maintain the uniform radio wave characteristics of the member which is arranged in front of the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  of the BLE communication unit  5 . Thus, it is possible to send and receive the wireless radio waves at the respective antennas under the same characteristic conditions, preventing from causing the differences in the characteristics of the wireless radio waves which are sent and received by the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  passing through the outer cover  65 . 
     Thus, it is possible to accurately calculate the direction in which the communication terminal  53  is positioned by correctly detecting the phase differences of the wireless radio waves among the antennas in the direction detection of the communication terminal  53  by means of the wireless radio waves. 
     As described above, in the embodiment, the BLE communication unit  5  is arranged on the front side of the main assembly  50   a  of the image forming apparatus  50 . Thus, when the BLE communication is performed with the communication terminal  53  which is carried by the user, it is possible to prevent the radio waves from being shielded by the main assembly  50   a,  the reading device  50   b,  etc. of the image forming apparatus  50  and to favorably detect the direction in which the communication terminal  53  is positioned by using the BLE communication. Further, by arranging the BLE communication unit  5  in the vicinity of the operation portion  400 , it is possible to more accurately detect the user who carries the communication terminal  53  and approaches the image forming apparatus  50  to operate the operation portion  400 . 
     Further, by arranging the BLE communication unit  5  in the vicinity of the operation unit  400 , below the operation portion  400  and above the image forming portion  500  in a vertical direction, that is, at a position relatively high in the main assembly  50   a,  it is possible to send and receive the direct wave of the arrival wireless radio wave with the sufficient radio wave strength by avoiding the influence of the obstacles existing between the image forming apparatus  50  and the communication terminal  53 . Thus, it is possible to favorably detect the direction in which the communication terminal  53  is positioned. 
     Embodiment 4 
     Next, a fourth embodiment will be described by using parts (a) to (d) of  FIG. 15  and parts (a) and (b) of  FIG. 16 .  FIG. 15  is a view showing a constitution of the image forming apparatus  50  illustrating the fourth embodiment, wherein part (a) of 
       FIG. 15  is an external appearance perspective view, part (b) of  FIG. 15  is a front view, part (c) of the  FIG. 15  is a side view, and part (d) of  FIG. 15  is a back view. Incidentally, in the embodiment, an only difference from the embodiment described above is an arrangement of the BLE communication unit  5 , and similar constitutions are indicated with same reference numerals and omitted from descriptions. Incidentally, in  FIG. 15 , the board  39  and the BLE antennas from  35  to  38  which constitute the BLE communication unit  5  are not shown, however, its constitution is same as in the first embodiment described above. 
     As shown in part (a) of  FIG. 15 , the front cover  100  is an outer cover to be opened when accessing the image forming portion  500  as described above, and is an outer cover which covers the image forming portion  500 . As shown in part (b) of  FIG. 2 , an area in which the image forming portion  500  is covered by the front cover  100  is an area  69 , and is an area which is adjacent to an area (area  68  as will be described below) which covers the BLE communication unit  5 . 
     In this way, since the BLE communication unit  5  is covered by the front cover  100  which is capable of opening and closing, it is possible to easily access to the BLE communication unit  5  by opening the front cover  100 . Thus, it is possible to easily perform a maintenance of the BLE communication unit  5 . 
     In the embodiment, the BLE communication unit  5  is arranged on the front portion of the main assembly  50   a  of the image forming apparatus  50  and below the operation portion  400 , and the BLE communication unit  5  is covered by the front cover  100 . That is, the BLE communication unit  5  in the embodiment is provided so that it is positioned on the front side of the image forming portion  500  in a front and rear direction of the image forming apparatus  50 . 
     In many cases, a user who carries the communication terminal  53  approaches from the front side of the image forming apparatus  50  to operate the operation portion  400  of the image forming apparatus  50 . For details, it will be described below, however, in order to detect a direction by the BLE communication of Bluetooth 5.1, it is necessary to send and receive a direct wave of a wireless radio wave which arrives in a straight line between the image forming apparatus  50  and the communication terminal  53  which is carried by the user. 
     In the embodiment, by arranging the BLE communication unit  5  on the front side of the main assembly  50   a  of the image forming apparatus  50 , it is possible to send and receive the direct wave of the wireless radio wave with the sufficient radio wave strength without being affected by shielding of the radio wave by the main assembly of the image forming apparatus  50 , etc., in the BLE communication with the communication terminal  53  which is carried by the user. 
     For example, in a case that the BLE communication unit  5  is arranged on the rear side of the image forming apparatus  50 , it may not be possible to obtain the sufficient radio wave strength since the radio wave is shielded by the unit inside the image forming apparatus  50  or the reading device  50   b.  On the other hand, in the embodiment, by arranging the BLE communication unit  5  on the front side of the main assembly  50   a  of the image forming apparatus  50 , it is possible to prevent the radio wave from being shielded by the image forming apparatus  50  itself. Further, by arranging the BLE communication unit  5  in the vicinity of the operation portion  400 , it is possible to more accurately detect the user who carries the communication terminal  53  and approaches the image forming apparatus  50  to operate the operation portion  400 . 
     Further, the BLE communication unit  5  is arranged in the vicinity of the operation portion  400  and below the operation portion  400  in a vertical direction, which is a relatively high position in the main assembly  50   a.  Here, the relatively high position with respect to the main assembly  50   a  is a position above the sheet feeding cassette  87  in the vertical direction. In this way, by arranging the BLE communication unit  5  at the relatively high position in the main assembly  50   a,  it is possible to send and receive the direct wave of the wireless radio wave with the sufficient radio wave strength, avoiding the influence of obstacles which exist between the image forming apparatus  50  and the communication terminal  53 . Incidentally, details of each constitution and arrangement of the BLE communication unit  5  will be described below. 
     As shown in  FIG. 15 , the image forming apparatus  50  is provided with the control portion  300  which controls the operation of the image forming portion  500 . In the embodiment, while the BLE communication unit  5  is arranged on the front side of the main assembly  50   a  of the image forming apparatus  50  as shown in parts (a) and (c) of  FIG. 15 , the control portion  300  is arranged on the rear side of the main assembly  50   a  as shown in parts (b) and (d) of  FIG. 15 . 
     Thus, the BLE communication unit  5  and the control portion  300  are electrically connected by the cable  5   a.  Since the cable  5   a  is passed through the cable guide  600  which is provided with the main assembly  50   a,  and is wired from the front surface to the rear surface in the main assembly  50   a,  it is easy to wire in the main assembly  50   a  and is designed to enhance workability when the image forming apparatus  50  is assembled or maintained. Incidentally, as shown in part (b) of  FIG. 15 , the cable guide  600  is provided below the reading device  50   b  and below the discharge tray  92  in the vertical direction, and is provided so that it is capable of opening and closing with respect to the main assembly  50   a.    
     As shown in part (a) of  FIG. 15 , the front cover  100  is an outer part which is provided so that it is capable of opening and closing at a position below the discharge tray  92  in the main assembly  50   a  and is formed by plastic resin. 
     Further, the front cover  100  is arranged to cover the front surface of the image forming apparatus  500  and the BLE communication unit  5 . Thus, the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  of the BLE communication unit  5  are covered by the front cover  100 . Here, the front cover  100  is an example of a cover member which covers the BLE communication unit  5  which is fixed to the metal plate  61 . 
       FIG. 16  is a view showing the front cover  100 . Part (a) of  FIG. 16  is a perspective view of the front cover  100  viewed from an inner surface  100   a  side. Part (b) of  FIG. 16  is a plan view showing a detailed constitution of the inner surface  100   a  of the outer cover  100 . Here, in the front cover  100 , a surface, which is inside the image forming apparatus  50  and faces toward an inside of the main assembly  50   a  while the front cover  100  is closed with respect to the main assembly  50   a,  is defined as the inner surface  100   a.  Further, in the outer cover  100 , a surface, which is inside the imaging forming apparatus  50  and opposes the support frame (the metal plate  61  and the BLE communication unit  5 ) while the front cover  100  is closed with respect to the main assembly  50   a,  is defined as the inner surface  100   a.  And, in the front cover  100 , a surface which forms an outer appearance of the image forming apparatus  50  is defined as the outer surface  100   b.    
     Here, the front cover  100  is molded from resin. In general, in a cover member which is formed using a resin material, ribs, bosses, etc. are formed on the inner surface  65   a  in order to ensure a strength. 
     In the front cover  100  of the embodiment, as shown in part (b) of  FIG. 16 , a plurality of ribs  66  as reinforcing ribs and a plurality of bosses  67  are formed on the inner surface  100   a.  In this way, the cover itself is prevented from being deformed by reinforcing the front cover  100  with the ribs  66  and the bosses  67 . However, even on the inner surface  100   a  of the front cover  100 , an area  68  includes a uniform surface where ribs  66  and bosses  67  are not formed. That is, since the ribs  66  and the bosses  67  are provided in an area other than the area  68 , the constitution of the area  68  is less unevenness compared to the other area on the inner surface  100   a  of the front cover  100 . On the other hand, in an area  69  which mainly covers the image forming portion  500 , the front cover  100  is reinforced by providing the ribs  66  and the bosses  67 . 
     The area  68  is arranged at the position to cover the area where the BLE communication portion  5  is arranged when the front cover  100  is mounted on the main assembly  50   a  in part (a) of  FIG. 15 . That is, the area  68  is the area which opposes the BLE communication portion  5  on the inner surface  100   a  of the front cover  100 , and the area which opposes the BLE antennas from  35  to  38 . Incidentally, the arrangement of the BLE communication unit  5  with respect to the area  68  of the outer cover is the same as what is described in the first embodiment by using  FIG. 7 . 
     Further, similar to the first embodiment as shown in part (b) of  FIG. 7 , the area  68  of the front cover  100  is molded so that the thickness f of the molding material is uniform. Thus, similar to the first embodiment, no ribs and no bosses are existed in the portion of the area  68  of the front cover  100  which covers the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  of the BLE communication unit  5 , and the portion of the area  68  is formed by molding resin so that the thickness f is uniform. 
     Thus, in the embodiment, it is also possible to maintain the uniform radio wave characteristics of the member which is arranged in front of the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  of the BLE communication unit  5 . Further, it is possible to send and receive the wireless radio waves at the respective antennas under the same characteristic conditions, preventing from causing the differences in the characteristics of the wireless radio waves which are sent and received by the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  passing through the front cover  100 , and it is possible to accurately calculate the direction in which the communication terminal  53  is positioned by correctly detecting the phase differences of the wireless radio waves among the antennas in the direction detection of the communication terminal  53  by means of the wireless radio waves. 
     As described above, in the embodiment, the BLE communication unit  5  is arranged on the front side of the main assembly  50   a  of the image forming apparatus  50 . Thus, when the BLE communication is performed with the communication terminal  53  which is carried by the user, it is possible to prevent the radio waves from being shielded by the main assembly  50   a,  the reading device  50   b,  etc. of the image forming apparatus  50  and to favorably detect the direction in which the communication terminal  53  is positioned by using the BLE communication. Further, by arranging the BLE communication unit  5  in the vicinity of the operation portion  400 , it is possible to more accurately detect the user who carries the communication terminal  53  and approaches the image forming apparatus  50  to operate the operation portion  400 . 
     Further, by arranging the BLE communication unit  5  in the vicinity of the operation unit  400 , below the operation portion  400  and above the sheet feeding cassette  87  in the vertical direction, that is, at a position relatively high in the main assembly  50   a,  it is possible to send and receive the direct wave of the arrival wireless radio wave with the sufficient radio wave strength by avoiding the influence of the obstacles existing between the image forming apparatus  50  and the communication terminal  53 . Thus, it is possible to favorably detect the direction in which the communication terminal  53  is positioned. 
     Further, in the embodiment described above, the BLE communication unit  5  is not fixed to the rotatable front cover  100  but to the metal plate  61  which is a part of the support frame of the main assembly  50   a.  That is, in the embodiment, the BLE communication unit  5  is immovable. In a case that the BLE communication unit  5  is fixed to the rotatable front cover  100 , the arrival radio wave may not be favorably detected due to inconsistency at all times of a detection range by the BLE communication unit  5 , by a rotational angle, an attachment error in the closed state, etc. of the front cover  100 . On the other hand, as in the embodiment, since it is possible to favorably detect the arrival radio wave by fixing the BLE communication unit  5  to an unrotatable member, it is possible to favorably detect the direction in which the communication terminal  53  is positioned. 
     As described above, it is possible to improve the performance of the image forming apparatus  50  by using the plurality of BLE antennas from  35  to  38  for detecting the arrival direction of the radio wave. 
     Embodiment 5 
     Next, a fifth embodiment will be described by using  FIG. 17  and  FIG. 18 .  FIG. 17  is a view showing a constitution of the image forming apparatus  50  in the fifth embodiment, wherein part (a) of  FIG. 17  is an external appearance perspective view, part (b) of  FIG. 17  is a side view, and part (c) of the  FIG. 17  is a back view. Incidentally, in the embodiment, an only difference from the embodiment described above is an arrangement of the BLE communication unit  5 , and similar constitutions are indicated with same reference numerals and omitted from descriptions. Incidentally, in  FIG. 17 , the board  39  and the BLE antennas from  35  to  38  which constitute the BLE communication unit  5  are not shown, however, its constitution is same as in the first embodiment described above. 
     In the embodiment, the outer cover  65  is below the image forming portion  500  in a vertical direction, and a cover member which constitutes an outer appearance of the image forming apparatus  50  below the front cover  100  of the main assembly  50   a.  Further, the outer cover  65  is the cover member which constitutes an outer appearance of the image forming apparatus  50  below the sheet feeding cassette  87  in a vertical direction of the image forming apparatus  50 . In the embodiment, a configuration, in which the feeding device  200  is provided in a lower portion of the main assembly  50   a  of the image forming apparatus  50 , is illustrated, and the outer cover  65  is a cover member which is provided between the sheet feeding cassette  87  and the feeding device  200  in a vertical direction. 
     Further, in the embodiment, the BLE communication unit  5  is arranged on a front portion of the main assembly  50   a  of the image forming apparatus  50  and below the sheet feeding cassette  87 . and the BLE communication unit  5  is covered with the outer cover  65 . Incidentally, the front side of the main assembly  50   a  is defined as a position on a front side of the image forming portion  500  in the front and rear direction of the image forming device  50 . 
     Further, the BLE communication unit  5  in the embodiment is provided so that it is positioned on the front side of the discharging roller pair  91  in the front and rear direction of the image forming apparatus  50 . Further, the BLE communication unit  5  in the embodiment is provided in the position in which it does not overlap with the operation portion  400  when the image forming apparatus  50  is viewed from the front side, even in the case that the operation portion  400  is rotated with respect to the main assembly  50   a.  Further, the BLE communication unit  5  in the embodiment is provided below the discharge tray  92  in the vertical direction of the image forming apparatus  50  and below the image forming portion  500 . 
     In many cases, a user who carries the communication terminal  53  approaches from the front side of the image forming apparatus  50  to operate the operation portion  400  of the image forming apparatus  50 . For details, it will be described below, however, in order to detect a direction by the BLE communication of Bluetooth 5.1, it is necessary to send and receive a direct wave of a wireless radio wave which arrives in a straight line between the image forming apparatus  50  and the communication terminal  53  which is carried by the user. 
     In the embodiment, by arranging the BLE communication unit  5  on the front side of the main assembly  50   a  of the image forming apparatus  50 , it is possible to send and receive the direct wave of the wireless radio wave with the sufficient radio wave strength without being affected by shielding of the radio wave by the main assembly of the image forming apparatus  50 , etc., in the BLE communication with the communication terminal  53  which is carried by the user. For example, in a case that the BLE communication unit  5  is arranged on the rear side of the image forming apparatus  50 , it may not be possible to obtain the sufficient radio wave strength since the radio wave is shielded by the unit inside the image forming apparatus  50  or the reading device  50   b.  However, in the embodiment, by arranging the BLE communication unit  5  on the front side of the main assembly  50   a  of the image forming apparatus  50 , it is possible to prevent the radio wave from being shielded by the image forming apparatus  50  itself. 
     Further, by arranging the BLE communication unit  5  at a relatively low position in a lower portion of a front surface of the main assembly, it is possible to send and receive the direct wave of the wireless radio wave with the sufficient radio wave strength, avoiding the influence of obstacles which exist between the image forming apparatus  50  and the communication terminal  53 . In particular, in many cases, a user stands in a front side of the image forming apparatus  50  and in front of the operation portion  400 . Considering a width of a human body, an upper body from a waist up may be thick, however, legs are thin compared to the upper body. 
     Thus, in the embodiment, even in a case that a user is in front of the operation portion  400 , it is possible to send and receive the direct wave of the wireless radio wave with sufficient radio wave strength, avoiding an influence of the human body by arranging the BLE communication unit  5  at a lower portion in which it is difficult to interfere with a communication between the communication terminal  53  which is carried by another user and the BLE communication unit  5 . 
     Incidentally, in the embodiment, a relatively low position of the image forming apparatus  50  is a position which is lower than the image forming portion  500  in a vertical direction and is lower than the front cover  100 . In the embodiment, a relatively low position of the image forming apparatus  50  is a position which is lower than the sheet feeding cassette  87  in a vertical direction. In a case that the image forming apparatus  50  includes only a small number of the sheet feeding cassettes  87 , for example, one, the BLE communication unit  5  may be constituted to be arranged between the front cover  100  and the sheet feeding cassette  87 . Even with the configuration, since the BLE communication unit  5  is arranged at a low position of the image forming portion  500  in a vertical direction and at a relatively low position of the image forming apparatus  50 , it is possible to send and receive the direct waves of the wireless radio wave with sufficient radio wave strength, avoiding the influence of the human body. 
     Further, it is possible to additionally reduce the influence of the human body, by arranging the BLE communication unit  5  at a position which is displaced from the operation portion  400  in a right and left direction of the image forming apparatus  50 . Thus, in the embodiment, an example of arranging the BLE communication unit  5  at a position which is shifted to a right side in the right and left direction is shown, however, the BLE communication unit  5  may be arranged at a position which is shifted to a left side in the right and left direction as long as the position does not overlap with the operation portion  400  in a vertical direction. Incidentally, the arrangement of the BLE communication unit  5  with respect to the area  68  of the outer cover is the same as what is described in the first embodiment by using  FIG. 7 . 
     In the embodiment, while the BLE communication unit  5  is arranged on a front side of the main assembly  50   a  of the image forming apparatus  50  as shown in parts (a) and (b) of  FIG. 17 , the control portion  300  is arranged on the rear side of the main assembly  50   a  as shown in parts (b) and (c) of  FIG. 17 . 
     Thus, the BLE communication unit  5  and the control portion  300  are electrically connected by the cable  5   a.  Since the cable  5   a  is passed through the cable guide  600 , which is provided with the main assembly  50   a,  is wired from a front surface to a rear surface in the main assembly  50   a,  it is easy to wire in the main assembly  50   a  and is designed to enhance workability when the image forming apparatus  50  is assembled or maintained. Incidentally, as shown in part (b) of  FIG. 17 , the cable guide  600  is arranged to avoid the image forming portion  500  below the reading device  50   b.    
     In the embodiment, as described above in part (a) of  FIG. 17 , the BLE communication unit  5  is arranged on a front portion of the image forming apparatus  50  and below the front cover  100 . 
       FIG. 18  is a view showing the outer cover  65 . As shown in part (a) of  FIG. 17 , the outer cover  65  is an outer part which is mounted below the sheet feeding cassette  87  in a vertical direction in the main assembly  50   a,  and covers the BLE communication unit  5 . Further, the outer cover  65  is provided below the front cover  100  in the vertical direction in the main assembly  50   a,  and is a cover member which is fixed to the main assembly  50   a  with fixtures such as screws. 
     Part (a) of  FIG. 18  is a perspective view of the outer cover  65  viewed from the inner surface  65   a  side. Part (b) of  FIG. 18  is a plan view showing a detailed constitution of the inner surface  65   a  of the outer cover  65 . Here, in the outer cover  65 , a surface, which is inside the image forming apparatus  50  and faces toward the inside of the main assembly  50   a  while the outer cover  65  is mounted on the main assembly  50   a,  is defined as the inner surface  65   a.  Further, in the outer cover  65 , a surface, which is inside the imaging forming apparatus  50  and opposes the support frame (the metal plate  61  and the BLE communication unit  5 ) while the outer cover  65  is mounted on the main assembly  50   a,  is defined as the inner surface  65   a.  And, in the outer cover  65 , a surface which forms an outer appearance of the image forming apparatus  50  is defined as the outer surface  65   b.    
     Here, the outer cover  65  is molded from resin. In general, in a cover member which is formed using a resin material, ribs, bosses, etc. are formed on the inner surface  65   a  in order to ensure a strength. 
     In the outer cover  65  of the embodiment, as shown in part (b) of  FIG. 18 , the ribs  66  are formed on its inner surface  65   a  as reinforcing ribs. In this way, the cover itself is prevented from being deformed by reinforcing it with the ribs  66 . Incidentally, a constitution, in which the outer cover  65  includes only the ribs  66 , is shown in the embodiment, however, it may be constituted to be reinforced with bosses, or it may be constituted to be reinforced with both ribs and bosses. 
     However, even the inner surface  65   a  of the outer cover  65  includes a uniform surface where the ribs  66  are not formed in the area  68 . That is, since the ribs  66  are provided in an area other than the area  68 , the area  68  is constituted to be less unevenness compared to the other area on the inner surface  65   a  of the outer cover  65 . 
     The area  68  is arranged at the position to cover the area where the BLE communication portion  5  is arranged when the outer cover  65  is mounted on the main assembly  50   a  in part (a) of  FIG. 17 . That is, the area  68  is the area which opposes the BLE communication portion  5  on the inner surface  65   a  of the outer cover  65 , and the area which opposes the BLE antennas from  35  to  38 . 
     Further, in the embodiment, similar to the first embodiment, the area  68  of the outer cover  65  is molded so that the thickness f of the molding material is uniform. 
     That is, no ribs and no bosses are existed in the portion of the area  68  of the outer cover  65  which covers the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  of the BLE communication unit  5 , and the portion of the area  68  is formed by molding resin so that the thickness f is uniform. 
     Thus, it is possible to maintain the uniform radio wave characteristics of the member which is arranged in front of the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  of the BLE communication unit  5 . That is, it is possible to send and receive the wireless radio waves at the respective antennas under same characteristic conditions, preventing from causing differences in characteristics of the wireless radio waves which are passed through the outer cover  65  and are sent and received by the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38 . 
     Thus, it is possible to accurately calculate the direction in which the communication terminal  53  is positioned by correctly detecting the phase differences of the wireless radio waves among the antennas in the direction detection of the communication terminal  53  by means of the wireless radio waves. 
     As described above, in the embodiment, the BLE communication unit  5  is arranged on the front side of the main assembly  50   a  of the image forming apparatus  50 . Thus, when the BLE communication is performed with the communication terminal  53  which is carried by the user, it is possible to prevent the radio waves from being shielded by the main assembly  50   a,  the reading device  50   b,  etc. of the image forming apparatus  50  and to favorably detect the direction in which the communication terminal  53  is positioned by using the BLE communication. Further, by arranging the BLE communication unit  5  in the vicinity of the operation portion  400 , it is possible to more accurately detect the user who carries the communication terminal  53  and approaches the image forming apparatus  50  to operate the operation portion  400 . 
     Further, the BLE communication unit  5  is arranged at a relatively low position in a lower portion of a front surface of the main assembly, and is arranged at a position below the front cover  100  or at a position blow the sheet feeding cassette  87  in a vertical direction. Thus, it is possible to send and receive the direct wave of the wireless radio wave with sufficient radio wave strength, avoiding an influence of obstacles which exist between the image forming apparatus  50  and the communication terminal  53 . Further even in a case that a user is in front of the operation portion  400 , it is possible to send and receive the direct wave of the wireless radio wave with sufficient radio wave strength, avoiding an influence of the human body by arranging the BLE communication unit  5  at a lower portion in which it is difficult to interfere with a communication between the communication terminal  53  which is carried by another user and the BLE communication unit  5  by a relatively wide upper body in the human body. Thus, it is possible to favorably detect the direction in which the communication terminal  53  is positioned. 
     Further, in the embodiment described above, the BLE communication unit  5  is not fixed to the rotatable front cover  100  but to the metal plate  61  which is a part of the support frame of the main assembly  50   a.  That is, in the embodiment, the BLE communication unit  5  is immovable. In a case that the BLE communication unit  5  is fixed to the rotatable front cover  100 , the arrival radio wave may not be favorably detected due to inconsistency at all times of a detection range by the BLE communication unit  5 , by the rotational angle, the attachment error in the closed state, etc. of the front cover  100 . On the other hand, as in the embodiment, since it is possible to favorably detect the arrival radio wave by fixing the BLE communication unit  5  to the unrotatable member, it is possible to favorably detect the direction in which the communication terminal  53  is positioned. 
     Embodiment 6 
     Next, a sixth embodiment will be described by using  FIGS. 19 through 21 .  FIG. 19  is a view showing a constitution of the image forming apparatus  50  in the sixth embodiment, wherein part (a) of  FIG. 19  is an external appearance perspective view, part (b) of  FIG. 19  is a front view, part (c) of the  FIG. 19  is a side view, and part (d) of  FIG. 19  is a back view. Incidentally, in the embodiment, an only difference from the embodiment described above is an arrangement of the BLE communication unit  5 , and similar constitutions are indicated with same reference numerals and omitted from descriptions. Incidentally, in  FIG. 19 , the board  39  and the BLE antennas from  35  to  38  which constitute the BLE communication unit  5  are not shown, however, its constitution is same as in the first embodiment described above. 
     The image forming apparatus  50  in the embodiment is provided with the BLE communication unit  5  which performs the short range wireless communication with the communication terminal  53  by BLE (Bluetooth Low Energy), so that the BLE communication unit  5  protrudes from a top of the reading device  50   b.  Further, the BLE communication unit  5  is constituted to protrude from the top of the feeding portion  50   b   1  of the reading device  50   b,  and is covered by the outer cover  65 . Incidentally, the BLE communication unit  5  is provided in a form of a board module which is constituted on a printed board. 
     Further, in the embodiment, as shown in  FIG. 19 , the BLE communication unit  5  is arranged in a rear side of the main assembly  50   a  of the image forming apparatus  50  and is arranged above the feeding portion  50   b   1 . Here, the position above the feeding portion  50   b   1  is a position which is above the sheet loading surface of the feeding portion  50   b   1 , and in which the BLE communication unit  5  does not overlap any members of the feeding portion  50   b   1  in case that the image forming apparatus  50  is viewed from the front. Further, the rear side of the main assembly  50   a  is a position in the rear side of the image forming portion  500  in a front and rear direction, and a position in the rear side of a rear end portion of the reading device  50   b  in the front and rear direction. Incidentally, in the embodiment, an example that the BLE communication unit  5  is fixed to the feeding portion  50   b   1  is described, however, it may be constituted to be fixed to the main assembly  50   a  as long as it protrudes from the feeding portion  50   b   1 . 
     Further, in the embodiment, the reading device  50   b  which includes the feeding portion  50   b   1  is described as an example, however, in a case of a constitution which includes only the reading portion  50   b   2  and a document cover (constitution which does not include the feeding portion  50   b ), the BLE communication unit  5  may be constituted to be provided at a position in which it protrudes above the reading portion  50   b   2  and it may be provided at a position in which it protrudes above an uppermost unit. 
     In many cases, a user who carries the communication terminal  53  approaches from the front side of the image forming apparatus  50  to operate the operation portion  400  of the image forming apparatus  50 . For details, it will be described below, however, in order to detect a direction by the BLE communication of Bluetooth 5.1, it is necessary to send and receive a direct wave of a wireless radio wave which arrives in a straight line between the image forming apparatus  50  and the communication terminal  53  which is carried by the user. 
     In the embodiment, by arranging the BLE communication unit  5  so that it protrudes from the top of the main assembly  50   a  of the image forming apparatus  50 , it is possible to send and receive the direct wave of the wireless radio wave with the sufficient radio wave strength without being affected by shielding of the radio wave by the main assembly of the image forming apparatus  50 , etc., in the BLE communication with the communication terminal  53  which is carried by the user. For example, in a case that the BLE communication unit  5  is arranged at a position in which it does not protrude from the top in a vertical direction in the rear side of the main assembly  50   a  of the image forming apparatus  50 , it may not be able to obtain the sufficient radio wave strength since the radio wave is shielded by a unit inside the image forming apparatus  50  and the reading device  50   b.  On the other hand, in the embodiment, by arranging the BLE communication unit  5  at the position in which it protrudes from the top of the image forming apparatus  50 , even in the rear side of the image forming apparatus  50 , it is possible to prevent the radio wave from being shielded by the image forming apparatus  50  itself. Further, although the BLE communication unit  5  is constituted to protrude from the image forming apparatus  50 , since the BLE communication unit  5  is provided in the rear side of the image forming apparatus  50 , it is possible to send and receive the direct waves of the wireless radio waves with the sufficient radio wave strength without deteriorating a user&#39;s operability. Further, by providing the BLE communication unit  5  in a right side which is same as the operation portion  400  in a width direction (right and left direction) of the image forming apparatus  50 , it is possible to more accurately detect a user who carries the communication terminal  53  and approaches the image forming apparatus  50  to operate the operation portion  400 . 
     Further, the BLE communication unit  5  is arranged at the highest position of the image forming apparatus  50  in a vertical direction. Here, the highest position with respect to the main assembly  50   a  is a position which is higher than any part of the feeding portion  50   b   1  of the reading device  50   b.  As a result, the position, in which the BLE communication unit  5  is provided, is a position above the image forming portion  500  and the front cover  100  in the vertical direction. 
     Further, the position, in which the BLE communication unit  5  is provided, is a position above the discharge tray  92  in the vertical direction. Here, the position above the discharge tray  92  in the vertical direction is a position above at least a part of the sheet loading surface of the discharge tray  92  in the vertical direction. 
     In this way, by arranging the BLE communication unit  5  at the highest position in the main assembly  50   a  and at a position which does not overlap with any units of the image forming apparatus  50  in the front and rear direction, it is possible to send and receive the direct wave of the wireless radio wave with the sufficient radio wave strength, avoiding the influence of obstacles which exist between the image forming apparatus  50  and the communication terminal  53 . Incidentally, details of each constitution of the BLE communication unit  5  will be described below. 
     In this embodiment, as shown in parts (c) and (d) of  FIG. 19 , the BLE communication unit  5  and the control portion  300  are arranged in the rear side of the image forming apparatus  50 . 
     Thus, the BLE communication unit  5  and the control portion  300  are electrically connected by the cable  5 . Since the cable  5   a  is passed through the cable guide  600  which is provided with the main assembly  50   a,  and is wired along the rear side of the image forming apparatus  50 , it is easy to wire in the main assembly  50   a  and is designed to enhance workability when the image forming apparatus  50  is assembled or maintained. 
     Next, a method, that the BLE communication unit  5  is arranged by fixing to the main assembly  50   a,  will be described by using  FIG. 20  and  FIG. 21 . Part (a) of  FIG. 20  is a view of the BLE communication unit  5  fixed to the metal plate  61  which is connected to the support frame of the main assembly  50   a,  viewed from the front of the image forming apparatus  50  (side in which the display portion  410  is arranged), and is a view of the BLE communication unit  5 , viewed from a thickness direction of the board. Thus, a lateral direction in part (a) of  FIG. 20  is a horizontal direction in which the image forming apparatus  50  is installed. Further, part (b) of  FIG. 20  is a sectional view of this, viewed from above the image forming apparatus  50 . 
     The metal plate  61  is a metal plate which is fixed to the frame plate constituting of the support frame of the main assembly  50   a  as described above. Incidentally, the support frame of the main assembly  50   a  is a support frame of the reading device  50   b  which is constituted of a metal plate. Here, the metal plate  61  may be fixed to a frame which supports each unit of the image forming portion  500 , or it may be a metal plate which is integrally formed with the support frame of the reading device  50   b  or it may be a metal plate which is formed separately. 
     The metal sheet  61  is connected to the support frame of the main assembly  50   a  and serves as the frame ground for the electric circuit, and is grounded via the ground wire, etc. 
     The metal spacer  62  is constituted of the metal member which is formed of metal, is the spacer for fixing the BLE communication unit  5  to the metal plate  61  and is fixed to the metal plate  61 . The resin spacer  64  is constituted of the resin member which is formed of plastic resin, is the spacer for fixing the BLE communication unit  5  to the metal plate  61  and is fixed to the metal plate  61 . 
     The screw  63  is the metal screw for fixing the BLE communication unit  5  to the metal spacer  62 , and fixes the BLE communication unit  5  by passing through the screw hole  43  which is provided with the BLE communication unit  5  and being tighten by the tap which is formed in the metal spacer  62 . As described above, the screw hole  43  which is provided with the BLE communication unit  5  is grounded to the electric circuit of the BLE communication unit  5 . 
     Thus, the ground of the electric circuit of the BLE communication unit  5  is connected to the metal plate  61  via the metal spacer  62  and the screw  63 , that is, it is connected to the frame ground of the electrical circuit of the main assembly  50   a.    
     The resin spacer  64  is formed so that its leading end portion penetrates the through hole  44  of the BLE communication unit  5 . Thus, the resin spacer  64  prevents the BLE communication unit  5  from rotating around the metal spacer  62 , when the BLE communication unit  5  is fixed to the metal plate  61 . 
     The outer cover  65  is an outer part which covers an outer surface of the BLE communication unit  5 , and is formed by plastic resin. Further, the outer cover  65  is arranged to cover the BLE communication unit  5 . Thus, the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  of the BLE communication unit  5  are covered by the outer cover  65 . Here, the outer cover  65  is an example of a cover member which covers the BLE communication unit  5  which is fixed to the metal plate  61 . 
     As described above, the BLE communication unit  5  is fixed to the metal plate  61  via the metal spacer  62  and the resin spacer  64 . In this case, the respective antennas of the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  of the BLE communication unit  5  are arranged and fixed to the metal plate  61  so that they are arrayed in the horizontal direction on the installation surface of the image forming apparatus  5 . Here, the metal spacer  62  is an example of the first support member, and the resin spacer  64  is an example of the second support member. 
     This is, as described above using part (a) of  FIG. 6  and part (b) of  FIG. 6 , due to detect the arrival angle and the sending angle of the wireless radio wave by using two of the antennas when performing the direction detection between the image forming apparatus  50  and the mobile communication terminal  53 . 
     That is, in the case of performing the direction detection between the image forming apparatus  50  and the communication terminal  53  which is present on the horizontal plane of the installation of the image forming apparatus  50 , it is possible to detect in all directions efficiently by arraying the respective BLE antennas in the horizontal direction. 
     Incidentally, as shown in part (b) of  FIG. 20 , the BLE communication unit  5  is fixed to the metal plate  61  by the metal spacer  62  and the resin spacer  64  with the distance e, so that it is parallel to the metal plate  61 . At this time, the BLE communication unit  5  is fixed to the metal plate  61  so that distances between each of the BLE antennas from  35  to  38  and the metal plate  61  are equally spaced. This is due to maintain the uniform distance between each of the BLE antennas from  35  to  38  which are formed on the BLE communication unit  5  and the metal plate  61 , and prevent the metal plate  61  from causing differences in the antenna characteristics of the BLE antennas from  35  to  38 . Thus, it is possible to send and receive the wireless radio waves under the same characteristic conditions of the respective antennas, and it is possible to correctly detect the phase difference of the wireless radio waves between the antennas in the direction detection by the wireless radio wave described above, and to accurately calculate the direction in which the communication terminal  53  as the communication target is positioned. 
       FIG. 21  is a view showing the outer cover  65 . As shown in part (a) of  FIG. 19 , the outer cover  65  is an outer part which is mounted so that it protrudes above the reading device  50   b  in the image forming apparatus  50 , and covers the BLE communication unit  5 . Further, the outer cover  65  is fixed to the reading device  50   b  or the main assembly  50   a  by unshown screws, etc. Here, the outer cover  65  may be constituted to be fixed to each support frame via an outer cover of the reading device  50   b  or an outer cover of the main assembly  50   a.    
     Part (a) of  FIG. 21  is an exploded perspective view of the outer cover  65 . Part (b) of  FIG. 21  is a plan view showing a detailed constitution of the inner surface  65   aa  of a first cover  65   a  of the outer cover  65 . Part (c) of  FIG. 21  is a plan view showing a detailed constitution of the inner surface  65  of a second cover  65   b  of the outer cover  65 . Incidentally, the BLE communication unit  5  is not shown in  FIG. 8 . 
     As described part (a) of  FIG. 21 , the outer cover  65  includes a first cover portion  65   a  which covers a front surface of the BLE communication unit  5  (a front side of the image forming apparatus  50  in a front and rear direction and a mounting surface of the BLE antennas from  35  to  38  on the board  39 ) and a second cover portion  65   b  which covers a rear surface of the BLE communication unit  5  (a rear side of the image forming apparatus  50  in the front and back direction and a rear surface of the board  39 ). 
     The BLE communication unit  5  is fixed to the second cover portion  65   b  with unshown fixtures such as screws, the BLE communication unit  5  is covered by the first cover portion  65   a  so that it is sandwiched, and is fixed to the second cover portion  65   b  by unshown fixtures such as screws. 
     Here, in the first cover  65   a  of the outer cover  65 , a surface which opposes the mounting surface of the antennas from  35  to  38  on the board  39  of the BLE communication unit  5  is defined as the inner surface  65   aa.  And, in the first cover  65   a  of the outer cover  65 , a surface which forms an outer appearance of the image forming apparatus  50  is defined as the outer surface  65   ab.  Further, in the second cover  65   b,  a surface which opposes the rear side of the board  39  of the BLE communication unit  5  is defined as the inner surface  65   ba,  and a surface which forms an outer appearance of the image forming apparatus  50  is defined as the outer surface  65   bb.    
     As described above, the metal plate  61  of the BLE communication unit  5  is grounded by being fixed or connected with a ground wire to the unshown support frame of the image forming apparatus  50 . 
     Here, the outer cover  65  is molded from resin. In general, in a cover member which is formed using a resin material, ribs, bosses, etc. are formed on the inner surface  65   aa  of the first cover  65   a  and the inner surface  65   ba  of the second cover  65   b  in order to ensure a strength. 
     In the outer cover  65  of the embodiment, as shown in part (b) of  FIG. 21 , the plurality of ribs  66  as reinforcing ribs and the plurality of bosses  67  are formed on the inner surface  65   aa  of the first cover  65   a.  In this way, the cover itself is prevented from being deformed by reinforcing the first cover  65   a  of the outer cover  65  with the ribs  66  and the bosses  67 . However, even on the inner surface  65   aa  of the first cover  65   a,  the area  68  includes the uniform surface where the ribs  66  and the bosses  67  are not formed. That is, since the ribs  66  and the bosses  67  are provided in an area other than the area  68 , the constitution of the area  68  is less unevenness compared to the other area on the inner surface  65   aa  of the first cover  65   a.    
     The area  68  is arranged at a position to cover the area where the BLE communication portion  5  is arranged in part (a) of  FIG. 19 . That is, the area  68  is the area which opposes the front of the BLE communication portion  5  on the inner surface  65   aa  of the first cover  65   a,  and the area which opposes the BLE antennas from  35  to  38 . 
     Further, as shown in part (b) of  FIG. 20 , the area  68  of the first cover  65   a,  which covers the BLE communication unit  5 , is molded so that the thickness f of the molding material is uniform. 
     That is, no ribs and no bosses are existed in the portion of the area  68  of the first cover  65   a  which covers the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  of the BLE communication unit  5 , and the portion of the area  68  is formed by molding resin so that the thickness f is uniform. 
     Thus, it is possible to maintain the uniform radio wave characteristics of the member which is arranged in front of the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  of the BLE communication unit  5 . That is, it is possible to send and receive the wireless radio waves at the respective antennas under same characteristic conditions, preventing from causing differences in characteristics of the wireless radio waves which are sent and received by the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38 , passing through the first cover  65   a.    
     Thus, it is possible to accurately calculate the direction in which the communication terminal  53  is positioned by correctly detecting the phase differences of the wireless radio waves among the antennas in the direction detection of the communication terminal  53  by means of the wireless radio waves. 
     Further, in the embodiment described above, a constitution is illustrated that in the outer cover  65 , only the first cover  65   a,  which is positioned in the front side of the image forming apparatus  50 , is provided with the area  68  in which the ribs  66  and the bosses  67  are not formed. On the other hand, the inner surface  65   ba  of the second cover  65   b  which is positioned in the rear side of the image forming apparatus  50 , is constituted to be uniformly provided with the ribs  66  and the bosses  67 . Since the second cover  65   b  is a member which opposes a rear surface which is an opposite side of a surface in which the BLE antennas from  35  to  38  are mounted with respect to the board  39 , and does not directly affect a performance of sending and receiving of the wireless radio waves, it may be constituted to include the ribs  66  and the bosses  67  in the front side, in this way. 
     In this way, since it is possible to increase a strength of the outer cover  65  by including the ribs  66  and the bosses  67  on a front surface of the inner surface  65   ba  of the second over portion  65   b,  which is one of cover members  65  which covers the BLE communication unit  5  in a front and back direction, it is possible to stably hold the BLE communication unit  5 . 
     As described above, in the embodiment, the BLE communication unit  5  is arranged so that it protrudes upward from the top of the image forming apparatus  50 . In more detail, the BLE communication unit  5  is arranged so that it protrudes upward from the feeding portion  50   b   1  of the reading device  50   b.  Thus, when the BLE communication is performed with the communication terminal  53  which is carried by the user, it is possible to prevent the radio waves from being shielded by the main assembly  50   a,  the reading device  50   b,  etc. of the image forming apparatus  50  and to favorably detect the direction in which the communication terminal  53  is positioned by using the BLE communication. Further, by arranging the BLE communication unit  5  in the rear side of the image forming apparatus  50 , it is possible to more accurately detect the user who carries the communication terminal  53  and approaches the image forming apparatus  50  to operate the operation portion  400 . Further, by arranging the BLE communication unit  5  in a same right side as the right side in which the operation portion  400  is positioned in a right and left direction (width direction) of the image forming apparatus  50 , it is possible to more accurately detect the user who carries the communication terminal  53  and approaches the image forming apparatus  50  to operate the operation portion  400 . 
     Further, by arranging the BLE communication unit  5  at the highest position in the main assembly  50   a,  which is above the operation portion  400  in the vertical direction, it is possible to send and receive the direct wave of the arrival wireless radio wave with the sufficient radio wave strength by avoiding the influence of the obstacles existing between the image forming apparatus  50  and the communication terminal  53 . Thus, it is possible to favorably detect the direction in which the communication terminal  53  is positioned. 
     Embodiment 7 
     Next, a seventh embodiment will be described by using  FIG. 22  and  FIG. 23 .  FIG. 22  is a view showing a constitution of the image forming apparatus  50  in the seventh embodiment, wherein part (a) of  FIG. 22  is an external appearance perspective view, part (b) of  FIG. 22  is a side view, and part (c) of the  FIG. 22  is a back view. Incidentally, in the embodiment, an only difference from the embodiment described above is an arrangement of the BLE communication unit  5 , and similar constitutions are indicated with same reference numerals and omitted from descriptions. Incidentally, in  FIG. 22 , the board  39  and the BLE antennas from  35  to  38  which constitute the BLE communication unit  5  are not shown, however, its constitution is same as in the first embodiment described above. 
     In case of the embodiment, the image forming apparatus  50  is provided with the BLE communication unit  5  which performs the short range wireless communication with the communication terminal  53  by BLE (Bluetooth Low Energy), so that the BLE communication unit  5  protrudes from a right side of the main assembly  50   a.  Further, the BLE communication unit  5  is constituted to protrude with respect to the outer cover of the main assembly  50   a,  and is covered by the outer cover  65 . Incidentally, the BLE communication unit  5  is provided in a form of a board module which is constituted on a printed board. 
     Further, in the embodiment, the BLE communication unit  5  is arranged on a side surface of the main assembly  50   a  of the image forming apparatus  50 , and is arranged below the operation portion  400 . Incidentally, in the embodiment, a sheet is discharged from a right side to a left side of the image forming apparatus  50  by the discharging roller pair  91 , so the BLE communication unit  5  is constituted to be provided on the right side surface of the main assembly  50   a  in the right and left direction, however, it may be provided on the left side surface of the main assembly  50   a  in case that a sheet discharge direction is from the left side to right side. Further, in a case that the sheet discharge direction is a front and rear direction with respect to the main assembly  50   a,  the BLE communication unit  5  may be provided on either side of right and left. Further, the BLE communication unit  5  may be provided so that it protrudes from a side surface of the reading device  50   b,  instead of being provided on the side surface of the main assembly  50   a.    
     Further, the BLE communication unit  5  in the embodiment is provided in the position in which it does not overlap with the operation portion  400  when the image forming apparatus  50  is viewed from the front side, even in the case that the operation portion  400  is rotated with respect to the main assembly  50   a.    
     In the embodiment, by arranging the BLE communication unit  5  on the side surface of the main assembly  50   a  of the image forming apparatus  50 , it is possible to send and receive the direct wave of the wireless radio wave with the sufficient radio wave strength without being affected by shielding of the radio wave by the main assembly of the image forming apparatus  50 , etc., in the BLE communication with the communication terminal  53  which is carried by the user. For example, in a case that the BLE communication unit  5  is arranged on the rear side of the image forming apparatus  50 , it may not be possible to obtain the sufficient radio wave strength since the radio wave is shielded by the unit inside the image forming apparatus  50  and the reading device  50   b.  On the other hand, in the embodiment, by arranging the BLE communication unit  5  on the side surface of the main assembly  50   a  of the image forming apparatus  50 , it is possible to prevent the radio wave from being shielded by the image forming apparatus  50  itself. Further, by arranging the BLE communication unit  5  in the vicinity of the operation portion  400 , it is possible to more accurately detect the user who carries the communication terminal  53  and approaches the image forming apparatus  50  to operate the operation portion  400 . 
     Further, the BLE communication unit  5  is arranged in the vicinity of the operation unit  400  and at a relatively high position of the image forming apparatus  50  in the vertical direction. Here, the relatively high position with respect to the main assembly  50   a  is a position above the image forming portion  500  and the front cover  100  in the vertical direction. 
     Further, the relatively high position with respect to the main assembly  50   a  is a position above the discharge tray  92  in the vertical direction. Here, the position above the discharge tray  92  in the vertical direction is a position above at least a part of the sheet loading surface of the discharge tray  92 . Further, the relatively high position with respect to the main assembly  50   a  is a position above the sheet feeding cassette  87  in the vertical direction. 
     In this way, by arranging the BLE communication unit  5  at the relatively high position in the main assembly  50   a,  it is possible to send and receive the direct wave of the wireless radio wave with sufficient radio wave strength, avoiding the influence of obstacles which exist between the image forming apparatus  50  and the communication terminal  53 . 
     Further, by providing the BLE communication unit  5  so that it protrudes from the side surface of the image forming apparatus  50 , it is possible to send and receive the direct wave of the wireless radio wave with sufficient radio wave strength, avoiding that the radio waves are shielded by an operator even in a case that the operator is existed in front of the image forming apparatus  50 . Incidentally, an arrangement of the BLE communication unit  5  with respect to the area  68  of the outer cover is the same as what is described in the first embodiment by using  FIG. 7 . 
     In the embodiment, while the BLE communication unit  5  is arranged in a front side of the main assembly  50   a  of the image forming apparatus  50  as shown in part (b) of  FIG. 22 , the control portion  300  is arranged in the rear side of the main assembly  50   a  as shown in part (b) of  FIG. 22 . 
     Thus, the BLE communication unit  5  and the control portion  300  are electrically connected by a cable  5 . Since the cable  5   a  is passed through a cable guide  600 , which is provided with the main assembly  50   a,  is wired from a front surface to a rear surface in the main assembly  50   a,  it is easy to wire in the main assembly  50   a  and is designed to enhance workability when the image forming apparatus  50  is assembled or maintained. 
     Next, a method, that the BLE communication unit  5  is arranged by fixing to the main assembly  50   a,  will be described by using  FIG. 23 . 
     The metal plate  61  shown in  FIG. 23  is a metal plate which is connected to the frame plate which constitutes the support frame of the main assembly  50   a.  Incidentally, the support frame of the main assembly  50   a  is a frame which supports each unit of the image forming apparatus  500 . Further, the support frame is a support frame which supports the reading device  50   b.  Here, the metal plate  61  may be a metal plate which is integrally formed with the support frame of the image forming portion  500  or it may be a metal plate which is formed separately. Here, detailed constitutions of the metal plate  61  and the BLE communication unit  5  which is fixed to the metal plate  61  are similar to the first embodiment, so the descriptions of them will be omitted. 
       FIG. 23  is a view showing the outer cover  65 . As shown in part (a) of  FIG. 22 , the outer cover  65  is an outer part which is mounted on the side surface of the main assembly  50   a,  and covers the BLE communication unit  5 . Further, the outer cover  65  is an outer part which is mounted below the operation portion  400 , and is fixed to the main assembly  50   a  by unshown screws, etc. 
     Part (a) of  FIG. 23  is an exploded perspective view of the outer cover  65 . Part (b) of  FIG. 23  is a plan view showing a detailed constitution of the inner surface  65   aa  of the first cover  65   a  of the outer cover  65 . As shown in part (a) of  FIG. 23 , the outer cover  65  includes the first cover  65   a  which covers the front surface of the BLE communication unit  5 , and the second cover  65   b  which covers the rear surface of the BLE communication unit  5 . Thus, the BLE communication unit  5  is fixed so as to be sandwiched between the first cover portion  65   a  and the second cover portion  65   b  in the front and rear direction. Here, in the first cover  65   a  of the outer cover  65 , a surface which opposes the BLE communication unit  5  is the inner surface  65   aa.  And, in the first cover  65   a  of the outer cover  65 , a surface which forms an outer appearance of the image forming apparatus  50  is defined as the outer surface  65   ab.    
     The metal plate  61  is fixed to a spacer  70  of the second cover  65   b  with screws  71 . Further, the first cover  65   a  is fixed to the second cover  65   b  with unshown screws, etc. As described above, the metal plate  61  is grounded by being fixed or connected with a ground wire to the unshown support frame of the image forming apparatus  50 . 
     Here, the outer cover  65  is molded from resin. In general, in a cover member, which is formed using a resin material, ribs, bosses, etc. are formed on the inner surface  65   aa  in order to ensure a strength. 
     In the outer cover  65  of the embodiment, as shown in part (b) of  FIG. 8 , the plurality of ribs  66  as reinforcing ribs and the plurality of bosses  67  are formed on the inner surface  65   a.  In this way, the cover itself is prevented from being deformed by reinforcing the first cover  65   a  of the outer cover  65  with the ribs  66  and the bosses  67 . However, even on the inner surface  65   a  of the outer cover  65 , the area  68  includes the uniform surface where the ribs  66  and the bosses  67  are not formed. That is, since the ribs  66  and the bosses  67  are provided in an area other than the area  68 , the area  68  is constituted to be less unevenness compared to the other area on the inner surface  65   a  of the outer cover  65 . 
     The area  68  is arranged at the position to cover the area where the BLE communication portion  5  is arranged in part (a) of  FIG. 22 . That is, the area  68  is the area which opposes the BLE communication portion  5  on the inner surface  65   aa  of the first cover  65   a,  and the area which opposes the BLE antennas from  35  to  38 . Further, similar to the first embodiment, the area  68  of the first cover  65   a  is molded so that the thickness f of the molding material is uniform. 
     That is, no ribs and no bosses are existed in the portion of the area  68  of the outer cover  65  which covers the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  of the BLE communication unit  5 , and the portion of the area  68  is formed by molding resin so that the thickness f is uniform. 
     Thus, it is possible to maintain the uniform radio wave characteristics of the member which is arranged in front of the BLE antenna  35 , the BLE antenna  36 , the BLE antenna  37 , and the BLE antenna  38  of the BLE communication unit  5 . Further, it is possible to send and receive the wireless radio waves at the respective antennas under same characteristic conditions, preventing from causing differences in characteristics of the wireless radio waves which are sent and received by the BLE antennas from  35  to  38 , passing through the outer cover  65 . 
     Thus, it is possible to accurately calculate the direction in which the communication terminal  53  is positioned by correctly detecting the phase differences of the wireless radio waves among the antennas in the direction detection of the communication terminal  53  by means of the wireless radio waves. 
     Incidentally, in the embodiment described above, the outer cover of the main assembly  50   a  and the outer cover  65  which covers the BLE communication unit  5  are constituted separately, however, the outer cover  65  may be constituted to be integrated into the outer cover which covers the main assembly  50   a.    
     Further, in the embodiment described above, a constitution is illustrated that in the outer cover  65 , only the first cover  65   a,  which is positioned in the front side of the image forming apparatus  50 , is provided with the area  68  in which the ribs  66  and the bosses  67  are not formed. On the other hand, since the second cover  65   b,  which is positioned in the rear side of the image forming apparatus  50 , is not in a direction from which the communication terminal  53  approaches, the second cover  65   b  is constituted to be provided uniformly with ribs and bosses. 
     As described above, in the embodiment, the BLE communication unit  5  is arranged on the side surface of the main assembly  50   a  of the image forming apparatus  50 . Thus, when the BLE communication is performed with the communication terminal  53  which is carried by the user, it is possible to prevent the radio waves from being shielded by the main assembly  50   a,  the reading device  50   b,  etc. of the image forming apparatus  50  and to favorably detect the direction in which the communication terminal  53  is positioned by using the BLE communication. Further, by arranging the BLE communication unit  5  in the vicinity of the operation portion  400 , it is possible to more accurately detect the user who carries the communication terminal  53  and approaches the image forming apparatus  50  to operate the operation portion  400 . 
     Further, by arranging the BLE communication unit  5  in the vicinity of the operation unit  400 , below the operation portion  400  and above the sheet feeding cassette  87  in the vertical direction, that is, at a position relatively high in the main assembly  50   a,  it is possible to send and receive the direct wave of the arrival wireless radio wave with the sufficient radio wave strength by avoiding the influence of the obstacles existing between the image forming apparatus  50  and the communication terminal  53 . Thus, it is possible to favorably detect the direction in which the communication terminal  53  is positioned. 
     Further, in the embodiment described above, the BLE communication unit  5  is not constituted to be provided with the rotatable front cover  100  etc., but the BLE communication unit  5  is immovable with respect to the main assembly  50   a.  In a case that the BLE communication unit  5  is fixed to a rotatable member such as the front cover  100 , the arrival radio wave may not be favorably detected due to inconsistency at all times of a detection range by the BLE communication unit  5 , by the rotational angle, the attachment error in the closed state, etc. of the front cover  100 . On the other hand, as in the embodiment, since it is possible to favorably detect the arrival radio wave by fixing the BLE communication unit  5  to the unrotatable member, it is possible to favorably detect the direction in which the communication terminal  53  is positioned. 
     In each of the embodiments described above, the constitution, in which the discharging roller pair  91  discharges a sheet to the discharge tray  92  from the right side to the left side in the right and left direction of the image forming apparatus  50 , is described, however, it may apply the embodiment to a constitution that a sheet is discharged from the left side to the right side in the right and left direction. Further, it may also apply to a configuration in which a sheet is discharged by the discharging roller pair  91  from the rear side toward the front side of the image forming apparatus  50 . 
     Further, in each of the embodiments described above, a constitution in which the discharge tray  92  is provided at a position below the reading device  50   b  and above the image forming portion  500  in a vertical direction, generally known as in body sheet discharge, is described, however, it may apply to a configuration in which the discharge tray is arranged outside the main assembly  50   a  (outside the reading device  50   b  in a right and left direction). Incidentally, the BLE communication unit  5  may be arranged, as shown in the embodiment, in the image forming apparatus  50  in which an unshown sheet processing device is connected in a downstream side in a sheet feeding direction, 
     As described above, it is possible to improve the performance of the image forming apparatus  50  by using the plurality of BLE antennas from  35  to  38  for detecting the arrival direction of the radio wave. 
     INDUSTRIAL APPLICABILITY 
     According to the present invention, an image forming apparatus which uses antennas to detect an arrival direction of a radio wave will be provided. 
     The present invention is not limited to the above embodiments, and various changes and variations are possible without departing from the spirit and scope of the present invention. Therefore, the following claims are attached to publicly disclose the scope of the present invention. 
     This application claims priority on the basis of Japanese Patent Application 2019-176272 filed Sep. 26, 2019, Japanese Patent Application 2019-176273 filed Sep. 26, 2019, Japanese Patent Application 2019-176274 filed Sep. 26, 2019, Japanese 
     Patent Application 2019-176275 filed Sep. 26, 2019, Japanese Patent Application 2019-176276 filed Sep. 26, 2019, and Japanese Patent Application 2019-176277 filed Sep. 26, 2019, the entire contents of which are hereby incorporated herein.