Patent Publication Number: US-2022236851-A1

Title: Information processing apparatus

Description:
BACKGROUND 
     Field 
     The present disclosure relates to an information processing apparatus. 
     Description of the Related Art 
     Because of improvements in transportation of people and goods, new viruses and mutant viruses can be rapidly spread all over the world, and large outbreaks of new viruses and mutant viruses have been frequently occurring. After many studies, it has been found that many of these infectious diseases are transmitted to people through intake of viruses contained in droplets exhaled from infected persons. Among the studies, some results show that such viruses can remain infective for several days on glass surfaces or plastic surfaces. In order to prevent people from being in contact with viruses as much as possible, various goods and devices usable or operable in a non-contact state are growing in demand. 
     The same can also be said for electric devices that are used by an unspecified large number of users. Electric devices which receive an input by a user&#39;s contact operation also need to be changed to non-contact operation supported devices to meet the demand for safer devices. Examples of such electric devices that need to be changed include a multifunction peripheral (MFP) serving as an image forming apparatus, which is used by many users and includes a contact-type touch panel display for receiving user touch operations. 
     As an example of a non-contact operation supported device, Japanese Patent Application Laid-Open No. 2016-062410 discusses an image forming apparatus including a capacitance-type touch panel that has detection areas including an area R 1  defined separate from the touch panel and an area R 2  defined farther separate from the touch panel than the area R 1 . A position of a user&#39;s finger is determined in the area R 2 , and a user&#39;s selection is determined in the area R 1 . With this configuration, the image forming apparatus can support functions for receiving an operation for searching a desired button and an operation for issuing an instruction which are performed by a user in a non-contact operation state. As another example, Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2016-520906 discusses an infrared-type display including a non-contact touch panel which supports a non-contact multi-touch operation on the infrared-type display. 
     SUMMARY 
     According to various embodiments of the present disclosure, an apparatus is provided that includes an operation unit configured to detect a position of an object being present perpendicular to a screen and receive, in a case where the position of the object being present perpendicular to the screen satisfies a first condition, a non-contact input based on the position of the object, wherein, in a case where the position of the object being present perpendicular to the screen satisfies a second condition of being present closer to the screen than a position specified in the first condition, the operation unit issues a warning without prohibiting an input based on the position of the object. 
     Further features of the present disclosure will become apparent from the following description of example embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram illustrating a configuration of an operation unit including a non-contact touch panel according to one embodiment. 
         FIG. 2A  is a block diagram illustrating a configuration of an operation unit including an infrared-type touch panel according to one embodiment.  FIG. 2B  is a block diagram of the infrared-type touch panel according to one embodiment. 
         FIG. 3  is an overhead view illustrating a state where a user intercepts a non-visible light beam with a physical object to select an operation key from an infrared-type touch panel according to one embodiment. 
         FIG. 4  is a configuration diagram illustrating an infrared-type touch panel on which non-contact sensors are arranged in three layers according to one embodiment. 
         FIGS. 5A to 5D  are diagrams illustrating an infrared-type touch panel on which non-contact sensors are arranged in three layers, each of which illustrates a state where a physical object intercepts a non-visible light beam at each layer according to one embodiment. 
         FIGS. 6A to 6D  are diagrams illustrating the infrared-type touch panel on which non-contact sensors are arranged in three layers, each of which illustrates contents of information displayed on a display unit when a physical object intercepts a non-visible light beam according to one embodiment. 
         FIG. 7  is a flowchart illustrating processing to be executed when the infrared-type touch panel includes non-contact sensors arranged in three layers according to one embodiment. 
         FIGS. 8A and 8B  are block diagrams illustrating a configuration of an operation unit including a capacitance-type touch panel according to one embodiment. 
         FIG. 9  is an overhead view illustrating a state where a user moves a physical object close to the capacitance-type touch panel to select an operation key according to one embodiment. 
         FIG. 10  is a diagram illustrating increase and decrease of capacitance of a sensor element when a physical object moves close to the capacitance-type touch panel according to one embodiment. 
         FIGS. 11A to 11D  are diagrams illustrating increase and decrease of capacitance of a sensor element and thresholds thereof when a physical object moves close to the capacitance-type touch panel according to one embodiment. 
         FIGS. 12A to 12D  are diagrams illustrating the capacitance-type touch panel, each of which illustrates contents of information displayed on the display unit when capacitance exceeds a threshold according to one embodiment. 
         FIG. 13  is a flowchart illustrating processing to be executed when thresholds are set for capacitance of the capacitance-type touch panel according to one embodiment. 
         FIG. 14  is a block diagram of an image forming apparatus according to one embodiment. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Example embodiments of the present disclosure will be described in detail with reference to the appended drawings. The example embodiments described hereinafter are not intended to limit the scope of the present invention, and not all of the combinations of features described in the example embodiments are required as the solutions of the present invention. In the present example embodiments, while an image forming apparatus will be described as an example of an information processing apparatus, the present invention is not limited thereto. 
     Hereinafter, a first example embodiment embodying various embodiments of the present disclosure will be described with reference to the drawings. 
       FIG. 14  is a block diagram of an image forming apparatus  10  according to the present example embodiment. 
     A central processing unit (CPU)  105  executes a software program stored in a random access memory (RAM)  104  to control the entire image forming apparatus  10 . 
     For example, a read only memory (ROM)  103  stores a program for starting a controller  100 , a program for executing image formation, and fixed parameters. 
     The RAM  104  is used for storing a program and temporary data when the CPU  105  controls the image forming apparatus  10 . The program and temporary data stored in the RAM  104  are a program and data read from the ROM  103  and a storage  502  described below. 
     A basic input/output system (BIOS)  107  is a non-volatile memory storing a boot program (BIOS). When printing processing is executed via a printer interface (I/F)  121 , a printer control unit  122  communicates with the CPU  105  to receive setting information set by a user, and controls operation of a printer unit  120  based on the setting information. 
     When scanning processing is executed via a scanner I/F  131 , a scanner control unit  132  communicates with the CPU  105  to receive setting information set by a user, and controls operation of a scanner unit  130  based on the setting information. 
     A network I/F  106  transmits and receives data via a network  118 . Specifically, the network I/F  106  receives data transmitted via the network  118 , and transmits image data read by the scanner unit  130  or stored in the storage  502  to a predetermined address via the network  118 . 
     A fax I/F  161  can transmit and receive a digital image to/from a phone line via a fax unit  160 . Specifically, the fax I/F  161  receives image data transmitted from the phone line via the fax unit  160 . Further, the fax I/F  161  transmits image data read by the scanner unit  130  or stored in the storage  502  to a predetermined address via the fax unit  160  and the phone line. 
     The storage  502  serves as a main storage to store a program to be executed by the CPU  105 , a program management table, and various types of data. The program to be executed by the CPU  105  is a boot program which is executed by the CPU  105  to boot an operating system (OS) when the image forming apparatus  10  is started. 
     Examples of the storage  502  include a hard disk drive (HDD), a solid state drive (SSD), an embedded multimedia card (eMMC), a NAND flash memory, and a NOR flash memory. The storage  502  stores therein information on whether an input method of an operation unit  200  is set to a non-contact input method or a contact input method, in association with a user when the user logs in the image forming apparatus  10 . 
     The controller  100  is connected to the operation unit  200  via an operation unit I/F  199 . The operation unit  200  and behavior of a user at the time of log-in to the image forming apparatus  10  will be described below in detail. 
       FIG. 1  is a block diagram illustrating an example of a hardware configuration of the operation unit  200  including a non-contact touch panel. 
     The information processing apparatus according to the present example embodiment will be described by taking an image forming apparatus including an operation unit as an example. 
     The operation unit  200  includes a control substrate  201 , a display unit  209 , and a non-contact touch panel  210 . An image processing unit  203  generates image data to be displayed on the display unit  209  and transmits the image data to the display unit  209  via a display unit I/F  206 . A touch panel control unit  204  acquires coordinate data from the non-contact touch panel  210  via a non-contact touch panel I/F  207 . Then, a microcomputer  202  acquires information from the touch panel control unit  204  and communicates with the controller via a controller I/F  205  and the operation unit I/F  199  based on the acquired information. 
     The controller is a device which communicates with the operation unit  200 . The controller I/F  205  is connected to the controller, and is also connected to respective units via a system bus  208 . The non-contact touch panel  210  is disposed over the top of the display unit  209 . The non-contact touch panel  210  receives an input when a user selects an operation key displayed on the display unit  209 . Examples of types of the non-contact touch panel  210  include an optical type and an ultrasonic type. Consequently, a type of the non-contact touch panel OF  207  is a type corresponding to the type used for the non-contact touch panel  210 . In the example embodiments according to the present disclosure, an infrared type and a capacitance type are used for the non-contact touch panel  210 . 
     A description will be given of a case where an infrared-type touch panel is used as the non-contact touch panel  210 .  FIG. 2A  is a block diagram illustrating an example of a hardware configuration of an operation unit including an infrared-type touch panel  211 . 
     An operation unit  200  includes a control substrate  201 , a display unit  209 , and an infrared-type touch panel  211 . An image processing unit  203  generates image data to be displayed on the display unit  209  and transmits the image data to the display unit  209  via a display unit OF  206 . A touch panel control unit  204  acquires coordinate data from the infrared-type touch panel  211  and communicates with a controller via a controller OF  205 . The controller is a device which communicates with the operation unit  200 . 
     The controller OF  205  is connected to the controller, and is also connected to each of the units via a system bus  208 . The infrared-type touch panel  211  is disposed over the top of the display unit  209 . The infrared-type touch panel  211  receives an input when a user selects an operation key displayed on the display unit  209 . 
       FIG. 2B  is a block diagram of the infrared-type touch panel  211 . The infrared-type touch panel  211  includes a control unit  212 , a light-emitting element  158 , and a light-receiving element  159 . The control unit  212  includes a detection unit  213 , a determination unit  214 , and a memory unit  215 . 
     The detection unit  213  controls the light-emitting element  158  and the light-receiving element  159  based on a determination result acquired by the determination unit  214 . According to an instruction from the determination unit  214 , the detection unit  213  switches an ON/OFF state of the light-emitting element  158 . The ON/OFF state of the light-emitting element  158  is switched by, for example, control of supplying driving power to the light-emitting element  158 . 
     The detection unit  213  detects received-light intensity of a light beam input to the light-receiving element  159  and transmits the detected received-light intensity to the control unit  212 . The control unit  212  transmits the received-light intensity received from the detection unit  213  to the determination unit  214 . According to an instruction from the determination unit  214 , the detection unit  213  switches an ON/OFF state of the light-receiving element  159 . The ON/OFF state of the light-receiving element  159  is switched in the same way as the switching in the light-emitting element  158 . 
     The determination unit  214  stores the received-light intensity, of the light beam input to the light-receiving element  159 , received from the detection unit  213  in the memory unit  215 . In the memory unit  215 , coordinates of the light-receiving element  159  and reference value data describing received-light intensity are stored. Based on the coordinates of the light-receiving element  159  and the reference value data stored in the memory unit  215 , the determination unit  214  executes determination of whether to display a pointer, whether a touch operation is performed, and whether to issue a warning. The determination unit  214  transmits information about coordinates and reference value data of the light-receiving element  159  at which the received-light intensity is changed, to the control substrate  201  via the non-contact touch panel OF  207 . The light-emitting element  158  is configured of, for example, a plurality of infrared light-emitting diodes (LEDs) and disposed along a periphery of the display unit  209  (see  FIG. 3 ). 
     The light-emitting element  158  emits an inspection light beam according to an instruction from the detection unit  213 . The inspection light beam emitted from the light-emitting element  158  is diffracted, intercepted, or reflected by a physical object  301 . The light-receiving element  159  is configured of, for example, a plurality of photodiodes and disposed along the periphery of the display unit  209  (see  FIG. 3 ). The light-receiving element  159  transmits received-light intensity to the detection unit  213 . 
       FIG. 3  is a diagram illustrating a state where a user selects an operation key  300  displayed on the display unit  209  on which the infrared-type touch panel  211  is disposed. On an outer frame of the infrared-type touch panel  211 , a plurality of infrared LEDs, or the like, including light-emitting elements  158  and  168  and a plurality of photodiodes, or the like, including light-receiving elements  159  and  169  are disposed in such a manner that each of the infrared LEDs faces a different one of the photodiodes. With this configuration, when a user&#39;s finger as the physical object  301  moves toward the operation key  300 , the physical object  301  is detected. 
     In the example illustrated in  FIG. 3 , the light-emitting elements  158  and the light-receiving elements  159  are disposed in an lateral direction which is an X-direction, and the light-emitting elements  168  and the light-receiving elements  169  are arranged in a longitudinal direction which is a Y-direction. An area where the operation key  300  is disposed is a touch detection area. Examples of the operation key  300  include a power saving key, a home button, a copy start key, a stop key, a color setting key, and a sheet size key. When an invisible light beam, such as an infrared light beam, emitted from the light-emitting element  158  to the light-receiving element  159  is intercepted by the physical object (object)  301 , such as a user&#39;s finger, the control substrate  201  detects corresponding coordinates. The display unit  209  outputs image data transmitted from the control substrate  201 . 
     With reference to  FIG. 4 , a description will be given of a case where the infrared-type touch panel  211  disposed on top of the operation unit  200  of the image forming apparatus  10  has a configuration in which light-emitting elements and light-receiving elements for detecting interception of invisible light beams caused by the physical object  301  are disposed in three layers in a perpendicular direction which is a Z-direction, i.e., disposed in three rows in the Z-direction. 
     For example, light-emitting elements  158  and  1580  are disposed on a first layer in the X-direction and the Y-direction, respectively. Light-emitting elements  258  and  2580  are disposed on a second layer in the X-direction and the Y-direction, respectively. Light-emitting elements  358  and  3580  are disposed on a third layer in the X-direction and the Y-direction, respectively. Each of the light-emitting elements is paired with a light-receiving element disposed at a position facing with a corresponding one of the light-emitting elements. The light-receiving elements transmit received-light intensity of received light beams to the control unit  212 . 
     With reference to  FIGS. 5A to 5D , a description will be given of operation relating to displaying of a pointer, determination of a touch operation, and issuance of a warning, which is executed in a case where interception of infrared light beams occurs in the infrared-type touch panel  211 . The description will be given of operation in the X-direction and the Z-direction. 
     The light-emitting elements  158 ,  258 , and  358 , and the light-receiving elements  159 ,  259 , and  359  are disposed in the Z-direction. For example, as illustrated in  FIG. 5B , in a case where a finger as the physical object  301  intercepts an invisible light beam emitted from the light-emitting element  158  to the light-receiving element  159  on the first layer, the control unit  212  detects interception of the invisible light beam based on received-light intensity transmitted from the light-receiving element  159 . The determination unit  214  stores the received-light intensity transmitted from the light-receiving element  159  via the detection unit  213  in the memory unit  215 . Based on the stored coordinates, the determination unit  214  determines that the first layer is intercepted, and transmits a notification to prompt the control substrate  201 . The touch panel control unit  204  receives the notification and instructs the display unit  209  to display a pointer on a point corresponding to the coordinates. 
     Next, as illustrated in  FIG. 5C , in a case where the finger intercepts an invisible light beam emitted from the light-emitting element  258  to the light-receiving element  259  on the second layer, the control unit  212  executes processing similar to the processing with respect to the light-receiving element  159 . The determination unit  214  determines that the second layer is intercepted at the stored coordinates, and transmits a notification to prompt the control substrate  201  to execute operation in response to a touch operation performed on a point corresponding to the coordinates on which the pointer is displayed. The microcomputer  202  receives the notification via the touch panel control unit  204  and executes operation in response to the touch. Alternatively, in a case where, in addition to the interception of the invisible light beam emitted to the light-receiving element  159 , the invisible light beam emitted to the light-receiving element  259  is also intercepted, the determination unit  214  may determine that the second layer is intercepted at the stored coordinates. 
     Next, as illustrated in  FIG. 5D , in a case where the finger intercepts an invisible light beam emitted from the light-emitting element  358  to the light-receiving element  359  on the third layer, the control unit  212  executes processing similar to the processing performed in response to the interceptions in the light-receiving elements  159  and  259 . In a case where the determination unit  214  determines that the third layer is intercepted at stored coordinates, the determination unit  214  transmits a notification to prompt the control substrate  201  to issue a warning. The touch panel control unit  204  receives the notification, and instructs the display unit  209  to display a warning color and a warning message for preventing the user from touching the touch panel, and instructs the microcomputer  202  to output a warning sound. Alternatively, in a case where, in addition to the interceptions of the invisible light beams emitted to the light-receiving elements  159  and  259 , the invisible light beam emitted to the light-receiving element  359  is also intercepted, the determination unit  214  may determine that the third layer is intercepted at the stored coordinates. 
     With reference to  FIGS. 6A to 6D , a description will be given of operation relating to displaying of a pointer, determination of a touch operation, and issuance of a warning, which are executed by the display unit  209  in synchronization with interception of an infrared light beam in the infrared-type touch panel  211 . 
       FIG. 6A  illustrates a state where the physical object  301  does not intercept an invisible light beam. For example, the display unit  209  displays a copy screen. 
       FIG. 6B  illustrates a state where the finger as the physical object  301  intercepts the invisible light beam emitted from the light-emitting element  158  to the light-receiving element  159  on the first layer. The display unit displays a pointer  318 , and the pointer  318  is moved according to a point corresponding to coordinates where the interception occurs. The pointer  318  may be displayed in a state illustrated in  FIG. 6A . In this case, in  FIG. 6A , the pointer  318  is not moved. 
       FIG. 6C  illustrates a state where the finger intercepts the invisible light beam emitted from the light-emitting element  258  to the light-receiving element  259  on the second layer. The display unit  209  displays that a touch operation is performed on the operation key  300  on which the pointer  318  is displayed, by inverting color of the operation key  300 , for example. 
       FIG. 6D  illustrates a state where the finger intercepts the invisible light beam emitted from the light-emitting element  358  to the light-receiving element  359  on the third layer. The display unit  209  changes a background color to another color, e.g., red color, different from a standard color and displays a warning message stating that the physical object  301  moves close to the touch panel, and the operation unit  200  outputs a warning sound. By issuing these warnings, it is possible to warn the user not to touch the touch panel. The warnings may be issued in combination with each other. 
       FIG. 7  is a flowchart illustrating a series of processing executed by the operation unit on which the infrared-type touch panel  211  is arranged. Content and conditions of the processing will be described below. The touch panel control unit  204  executes control described in this flowchart. 
     A procedure of processing in  FIG. 7  is started when the image forming apparatus  10  is turned on, and an image, e.g., a user authentication screen or a home screen, is displayed on the display unit  209 . 
     In step S 101 , in a case where the touch panel control unit  204  receives a notification indicating a state where the detection unit  213  detects interception by the physical object  301  of an invisible light beam emitted from the light-emitting element to the light-receiving element on the first layer (YES in step S 101 ), the processing proceeds to step S 103 . 
     In step S 103 , the touch panel control unit  204  instructs the display unit  209  to display a pointer. Then, the processing proceeds to step S 104 . 
     In a case where the invisible light beam on the first layer is not intercepted (NO in step S 101 ), the processing proceeds to step S 102 . In step S 102 , the touch panel control unit  204  causes the display unit  209  to display no pointer. Herein, “displaying no pointer” refers to a state where a hidden state of the pointer is maintained or a displayed state of the pointer is shifted to a hidden state. 
     In step S 104 , the display unit  209  receives the instruction for displaying a pointer and displays a pointer  318 . Then the processing proceeds to step S 105 . In a case where the pointer  318  has already been displayed on the display unit  209 , the displayed state of the pointer  318  is maintained. 
     In step S 105 , in a case where the touch panel control unit  204  receives a notification indicating a state where the detection unit  213  detects interception by the physical object  301  of an invisible light beam emitted from the light-emitting element to the light-receiving element on the second layer (YES in step S 105 ), the processing proceeds to step S 106 . In step S 105 , in a case where the touch panel control unit  204  does not receive a notification indicating a state where the detection unit  213  detects interception by the physical object  301  of an invisible light beam emitted from the light-emitting element to the light-receiving element on the second layer (NO in step S 105 ), the processing returns to step S 101 . 
     In step S 106 , the touch panel control unit  204  acquires coordinates of the light-receiving element, at which the interception has occurred, from the memory unit  215 , and instructs the display unit  209  to invert color of a point corresponding to the coordinates. Then, the processing proceeds to step S 107 . 
     In step S 107 , the display unit  209  inverts the color of the point corresponding to the coordinates. Then, the processing proceeds to step S 108 . 
     In step S 108 , the touch panel control unit  204  determines that the color inverted point corresponding to the coordinates is a position decided by the user, i.e., the touch panel control unit  204  determines that a touch operation is performed by the user. Then, the processing proceeds to step S 109 . 
     In step S 109 , in a case where the touch panel control unit  204  receives a notification indicating a state where the detection unit  213  detects interception by the physical object  301  of an invisible light beam emitted from the light-emitting element to the light-receiving element on the third layer (YES in step S 109 ), the processing proceeds to step S 110 . In step S 109 , in a case where the touch panel control unit  204  does not receive a notification indicating a state where the detection unit  213  does not detect interception by the physical object  301  of an invisible light beam emitted from the light-emitting element to the light-receiving element on the third layer (NO in step S 109 ), the processing returns to step S 101 . 
     In step S 110 , the touch panel control unit  204  instructs the display unit  209  and the microcomputer  202  to issue warnings. Then, the processing proceeds to step S 111 . 
     In step S 111 , as an operation for issuing a warning, the display unit  209  changes a background color and displays a warning message, and the microcomputer  202  outputs a warning sound. In step S 111 , an input by the user is not prohibited. This is because the user intentionally moves the finger to execute a touch operation. Specifically, in step S 111 , when the invisible light beam on the third layer is intercepted, the invisible light beam on the second layer is also intercepted, and thus although the warnings are issued, the touch panel control unit  204  determines that the color inverted point is a position decided by the user, by the processing similar to the processing in step S 108 . 
     In step S 112 , in a case where contact between the display unit  209  and the physical object  301  is detected (YES in step S 112 ), the touch panel control unit  204  advances the processing to step S 113 . In a case where contact between the display unit  209  and the physical object  301  is not detected (NO in step S 112 ), the touch panel control unit  204  returns the processing to step S 111 . 
     In step S 113 , the touch panel control unit  204  registers an ID of the log-in user to track the ID through an information network, such as the Contact-Confirming Application (COCOA) which is a cooperative checking system between users to check contact with a person infected with a coronavirus. Then, the processing proceeds to step S 114 . In this process, the touch panel control unit  204  may execute control to change an input function to a touch input function which allows a user to input information by physically touching the display unit  209  with a finger. In a case where the input function is changed to the physical-touch input function, a non-contact input function may be turned off for a certain period. In step S 114 , the touch panel control unit  204  causes the microcomputer  202  to provide a notification of sterilization to the user. This notification of sterilization may be displayed on the display unit  209 . 
     According to the present example embodiment, the operation unit  200  executes control based on a position of the user&#39;s finger. This configuration can reduce or prevent incorrect inputs from the user. 
     In the example illustrated in  FIG. 7 , the touch panel control unit  204  executes the respective pieces of processing. However, the present example embodiment is not limited thereto. alternatively, the CPU  105  of the controller  100  illustrated in  FIG. 14  may be employed. 
     In a case where the CPU  105  is employed, the processing in  FIG. 7  will be executed as follows. In this case, the operation unit  200  internally executes the above-described processing executed by the touch panel control unit  204 . 
     In step S 101 , in a case where the CPU  105  receives a notification indicating a state where the detection unit  213  detects interception by the physical object  301  of an invisible light beam emitted from the light-emitting element to the light-receiving element on the first layer, from the operation unit  200  (YES in step S 101 ), the processing proceeds to step S 103 . 
     In step S 103 , the CPU  105  instructs the operation unit  200  to display a pointer. Then, the processing proceeds to step S 104 . 
     In a case where the invisible light beam on the first layer is not intercepted (NO in step S 101 ), the processing proceeds to step S 102 . In step S 102 , the CPU  105  causes the operation unit  200  to display no pointer. Herein, “displaying no pointer” refers to a state where a hidden state of the pointer is maintained or a state where a displayed state of the pointer is shifted to a hidden state. 
     In step S 104 , the operation unit  200  receives the instruction for displaying a pointer and displays the pointer  318 . Then, the processing proceeds to step S 105 . In a case where the pointer  318  has already been displayed on the display unit  209 , a displayed state of the pointer  318  is maintained. 
     In step S 105 , in a case where the CPU  105  receives a notification indicating a state where the detection unit  213  detects interception by the physical object  301  of an invisible light beam emitted from the light-emitting element to the light-receiving element on the second layer (YES in step S 105 ), the processing proceeds to step S 106 . In step S 105 , in a case where the CPU  105  does not receive a notification indicating a state where the detection unit  213  detects interception by the physical object  301  of an invisible light beam emitted from the light-emitting element to the light-receiving element on the second layer (NO in step S 105 ), the processing returns to step S 101 . 
     In step S 106 , the CPU  105  acquires coordinates of the light-receiving element at which interception has occurred, from the operation unit  200 , and instructs the operation unit  200  to invert color of a point corresponding to the coordinates. Then, the processing proceeds to step S 107 . 
     In step S 107 , the CPU  105  instructs the operation unit  200  to invert the color of the point corresponding to the coordinates. Then, the processing proceeds to step S 108 . In step S 108 , the CPU  105  determines that the color inverted point corresponding to the coordinates is a position decided by the user, i.e., the CPU  105  determines that a touch operation is performed by the user. Then, the processing proceeds to step S 109 . 
     In step S 109 , in a case where the CPU  105  receives a notification indicating a state where the detection unit  213  detects interception by the physical object  301  of an invisible light beam emitted from the light-emitting element to the light-receiving element on the third layer (YES in step S 109 ), the processing proceeds to step S 110 . In step S 109 , in a case where the CPU  105  does not receive a notification indicating a state where the detection unit  213  detects interception by the physical object  301  of an invisible light beam emitted from the light-emitting element to the light-receiving element on the third layer (NO in step S 109 ), the processing returns to step S 101 . 
     In step S 110 , the CPU  105  transmits an instruction for issuing warnings to the display unit  209  and the microcomputer  202 . Then, the processing proceeds to step S 111 . 
     In step S 111 , the touch panel control unit  204  causes the display unit  209  to change a background color and display a warning message, and causes the microcomputer  202  to output a warning sound, as operation for issuing warnings. 
     In step S 112 , in a case where contact between the display unit  209  of the operation unit  200  and the physical object  301  is detected (YES in step S 112 ), the CPU  105  advances the processing to step S 113 . In a case where contact between the display unit  209  and the physical object  301  is not detected (NO in step S 112 ), the CPU  105  returns the processing to step S 111 . 
     In step S 113 , the CPU  105  registers an ID of the log-in user to track the ID through an information network, such as “COCOA” which is a cooperative checking system between users to check contact with a person infected with a coronavirus. Then, the processing proceeds to step S 114 . In step S 114 , the CPU  105  causes the operation unit  200  to provide a notification of sterilization to the user. This notification of sterilization may be displayed on the display unit  209 . 
     A second example embodiment will be described using a case where a capacitance-type touch panel is used as the non-contact touch panel  210 . The same reference numeral is applied to an element similar to that of the first example embodiment, and redundant descriptions thereof will be omitted. 
       FIGS. 8A and 8B  are block diagrams illustrating a hardware configuration of an operation unit including a capacitance-type touch panel  216 . Because the elements except for the capacitance-type touch panel  216  are similar to those illustrated in  FIGS. 2A and 2B , redundant descriptions thereof will be omitted. 
     First,  FIG. 8A  will be described. An operation unit  200  includes the capacitance-type touch panel  216 . A touch panel control unit  204  acquires coordinate data from the capacitance-type touch panel  216  and communicates with a controller via a controller OF  205 . 
     The capacitance-type touch panel  216  is disposed over the top of a display unit  209 . The capacitance-type touch panel  216  receives an input when a user selects an operation key displayed on the display unit  209 . The capacitance-type touch panel  216  includes a control unit  217  and a sensor unit  221 . The control unit  217  includes a detection unit  218 , a determination unit  219 , and a memory unit  220 . 
     The sensor unit  221  includes a driving unit  222 , a detected data generation unit  223 , and an operation panel  224 . The detection unit  218  controls the sensor unit  221  to periodically execute detection at each detection position on the operation panel  224 , i.e., periodically execute detection at intersection points where sensor elements  227  of a capacitance type are formed. The above control includes control of an application timing of voltage and a level of voltage applied to an electrode Ey  226  from the driving unit  222  and control of a reading timing of the detected data generation unit  223  of detected data from the electrode Ey  226 . 
     Based on the detected data received from the sensor unit  221  via the detection unit  218 , the determination unit  219  stores an amount of change in capacitance of each detection position on the operation panel  224  in the memory unit  220 . 
     Coordinates of a sensor element, reference value data indicating a capacitance, and thresholds are stored in the memory unit  220 . Specifically, the thresholds include a threshold T 1  for displaying of a pointer, a threshold T 2  for determination of a touch operation, and a threshold T 3  for issuing of a warning. 
     The operation panel  224  will be described with reference to  FIG. 8B . The operation panel  224  is used as a user interface for receiving an input. The operation panel  224  includes a plurality of electrodes Ex  225  disposed along a first direction (e.g., X-direction) and a plurality of electrodes Ey  226  disposed along a second direction (e.g., Y-direction) orthogonal to the first direction. The electrodes Ex  225  and the electrodes Ey  226  intersect with each other in a mutually-insulated state, and the sensor elements  227  of a capacitance type are formed in the vicinities of intersection points of the electrodes Ex  225  and the electrodes Ey  226 . 
     An arrangement pattern of the electrodes Ex  225  and the electrodes Ey  226  is not limited to a grid pattern, but can be any optional pattern, such as a diamond pattern (i.e., rhombic pattern), as long as the electrodes Ex  225  and the electrodes Ey  226  intersect with each other. The driving unit  222  applies driving voltage to each of the sensor elements  227 . For example, according to the control executed by the detection unit  218 , the driving unit  222  sequentially selects a plurality of electrodes Ex  225  to apply voltage that changes periodically to the selected electrodes Ex  225 . 
     Because of the application of voltage, potential of the sensor element  227  is changed and thus electric discharge/charge occurs. A capacitance of the sensor element  227  is detected by detecting a charge amount at the electrode Ey  226 . The electrode Ey  226  supplies a capacitance detected at each of intersection points of a corresponding row to the detected data generation unit  223 . The detected data is, for example, digital data of voltage values digitally sampled based on the capacitance of each of the intersection points. The detected data is supplied to the detection unit  218 . 
       FIG. 9  is a diagram illustrating a state where the user selects an operation key  300  displayed on the display unit  209  on which the capacitance-type touch panel  216  is disposed. When the user&#39;s finger as a physical object  301  moves toward an operation key  300 , the electrode Ey  226  detects a capacitance of a sensor element  227  in an area where the operation key  300  is arranged. The detected data is supplied to the control substrate  201 . 
     Examples of the operation key  300  is similar to the above-described examples of the operation key  300 . 
       FIG. 10  is a diagram illustrating a change in capacitance of the sensor element  227  on the capacitance-type touch panel  216 . The capacitance-type touch panel  216  includes electrodes Ex  225  extending in the X-direction and electrodes Ey  226  extending in the Y-direction. Capacitance is generated at each of intersection points between the electrodes Ex  225  and the electrodes Ey  226 , and a capacitance of the sensor element  227  is changed. For example, the electrode Ex  225  can be used as a driving electrode, and the electrode Ey  226  can be used as a detection electrode. 
     By applying periodically changing voltage to the electrode Ex  225  of the capacitance-type touch panel  216 , potential of the sensor element  227  is changed and thus electric discharge/charge occurs. A capacitance of the sensor element  227  can be detected by detecting a capacitance at the electrode Ey  226 . For example, when a finger as the physical object  301  moves close to the operation panel  224 , the capacitance of the sensor element  227  is changed (increased) remarkably because of capacitance coupling between the physical object  301  and the electrode Ey  226 . On the contrary, when the physical object  301  moves away from the operation panel  224 , the capacitance of the sensor element  227  is changed (decreased) because capacitance coupling between the physical object  301  and the electrode Ey  226  does not occur. 
     With reference to  FIGS. 11A to 11D , a description will be given of operation of detecting the threshold T 1  for displaying of a pointer, the threshold T 2  for determination of a touch operation, and the threshold T 3  for issuing of a warning, in the capacitance-type touch panel  216  disposed on the operation unit  200 . For example, as illustrated in  FIGS. 11A and 11B , a finger as the physical object  301  moves close to the operation panel  224 . In a case where the determination unit  219  determines that a detected capacitance of the sensor element  227  exceeds the threshold T 1  stored in the memory unit  220 , the control unit  217  transmits a notification to prompt the control substrate  201  to display a pointer. The touch panel control unit  204  receives the notification and transmits an instruction for displaying a pointer on a point corresponding to the coordinates to the display unit  209 . 
     Next, as illustrated in  FIGS. 11B and 11C , the finger as the physical object  301  moves closer to the operation panel  224 . In a case where the determination unit  219  determines that a detected capacitance of the sensor element  227  exceeds the threshold T 2  stored in the memory unit  220 , the control unit  217  transmits a notification to prompt the control substrate  201  to perform processing in response to a touch operation performed on the point corresponding to the coordinates on which the pointer is displayed. The microcomputer  202  receives the notification via the touch panel control unit  204  and performs the processing in response to the touch operation. 
     Subsequently, as illustrated in  FIGS. 11C and 11D , the finger as the physical object  301  further moves closer to the operation panel  224 . In a case where the determination unit  219  determines that a detected capacitance of the sensor element  227  exceeds the threshold T 3  stored in the memory unit  220 , the control unit  217  transmits a notification to prompt the control substrate  201  to issue a warning. 
     The touch panel control unit  204  receives the notification and displays a warning message on the display unit  209 . 
     With reference to  FIGS. 12A to 12D , a description will be given of operation of detecting the threshold T 1  for displaying of a pointer, the threshold T 2  for determination of a touch operation, and the threshold T 3  for issuing of a warning, in the capacitance-type touch panel  216  disposed on the operation unit  200 .  FIG. 12A  illustrates a state where a capacitance of the sensor element  227  does not reach the threshold T 1  when the physical object  301  is at a position illustrated in  FIG. 12A . 
       FIG. 12B  illustrates a state where the finger as the physical object  301  moves close to the operation panel  224 , and the determination unit  219  determines that a detected capacitance of the sensor element  227  exceeds the threshold T 1  stored in the memory unit  220 . The display unit  209  displays a pointer  318 , and the pointer  318  is moved in accordance with a point corresponding to the coordinates. 
       FIG. 12C  illustrates a state where the determination unit  219  determines that a detected capacitance of the sensor element  227  exceeds the threshold T 2  stored in the memory unit  220 . The display unit  209  displays that a touch operation with respect to the operation key  300  on which the pointer  318  is displayed is performed. For example, the display unit  209  inverts color of the operation key  300 . 
       FIG. 12D  illustrates a state where the determination unit  219  determines that a detected capacitance of the sensor element  227  exceeds the threshold T 3  stored in the memory unit  220 . The display unit  209  changes a background color of display to another color (e.g., red color) different from a standard color, and the operation unit  200  outputs a warning sound. 
       FIG. 13  is a flowchart illustrating a series of processing executed in the operation unit on which the capacitance-type touch panel  216  is arranged. A procedure and conditions of the processing will be described below. The touch panel control unit  204  executes control described in this flowchart. 
     A procedure of processing in  FIG. 13  is started when the image forming apparatus  10  is turned on, and an image, such as a user authentication screen and a home screen, is displayed on the display unit  209 . 
     In step S 201 , the touch panel control unit  204  determines whether a capacitance of the sensor element  227  exceeds the threshold T 1  by the physical object  301  moving close to the operation panel  224 . In a case where the capacitance exceeds the threshold T 1  (YES in step S 201 ), the processing proceeds to step S 203 . In step S 201 , in a case where the capacitance does not exceed the threshold T 1  (NO in step S 201 ), the processing proceeds to step S 202 . 
     In step S 202 , the touch panel control unit  204  causes the display unit  209  to display no pointer. The processing returns to step S 201  when the processing in step S 202  is ended. The determination in step S 201  may be executed by the microcomputer  202 . 
     In step S 203 , the touch panel control unit  204  instructs the display unit  209  to display a pointer. Then, the processing proceeds to step S 204 . 
     In step S 204 , the display unit  209  receives the instruction for displaying a pointer and displays the pointer  318 . Then the processing proceeds to step S 205 . 
     In step S 205 , the touch panel control unit  204  determines whether a capacitance of the sensor element  227  exceeds the threshold T 2 . In a case where the capacitance exceeds the threshold T 2  (YES in step S 205 ), the processing proceeds to step S 206 . In step S 205 , In a case where the capacitance of the sensor element  227  does not exceed the threshold T 2  (NO in step S 205 ), the processing returns to step S 201 . The determination in step S 205  may be executed by the microcomputer  202 . 
     In step S 206 , the touch panel control unit  204  acquires coordinates of the sensor element  227  from the memory unit  220 , and instructs the display unit  209  to invert color of a point corresponding to the coordinates. Then, the processing proceeds to step S 207 . 
     In step S 207 , the display unit  209  receives the instruction for inverting the color of the point corresponding to the coordinates, and inverts the color of the point corresponding to the coordinates. Then, the processing proceeds to step S 208 . 
     In step S 208 , the touch panel control unit  204  determines that the color inverted point corresponding to the coordinates is a position decided by the user, i.e., the touch panel control unit  204  determines that a touch operation is performed by the user. Then, the processing proceeds to step S 209 . The determination in step S 208  may be executed by the microcomputer  202 . 
     In step S 209 , the touch panel control unit  204  determines whether a capacitance of the sensor element  227  exceeds the threshold T 3 . In a case where the capacitance exceeds the threshold T 3  (YES in step S 209 ), the processing proceeds to step S 210 . The processing proceeds to step S 211  when the processing in step S 210  is ended. On the other hand, In a case where the capacitance does not exceed the threshold T 3  (NO in step S 209 ), the processing returns to step S 201 . The determination in step S 209  may be executed by the microcomputer  202 . 
     In step S 210 , the touch panel control unit  204  instructs the display unit  209  and the microcomputer  202  to issue warnings. In step S 211 , as operation for issuing warnings, the display unit  209  changes a background color of display and displays a warning message. Further, the touch panel control unit  204  causes the microcomputer  202  to output a warning sound. The processing proceeds to step S 212  when the processing in step S 211  is ended. 
     In step S 212 , the touch panel control unit  204  determines whether the physical object  301  is in contact with the display unit  209 . In a case where the physical object  301  is in contact with the display unit  209  (YES in step S 212 ), the processing proceeds to step S 213 . In step S 213 , the touch panel control unit  204  registers an ID of the log-in user to track the ID through an information network, such as “COCOA” which is a cooperative check system between users to check contact with a person infected with a coronavirus. Then, the processing proceeds to step S 214 . In step S 214 , the touch panel control unit  204  provides a notification of sterilization to the user. This notification of sterilization may be displayed on the display unit  209 . 
     In the example illustrated in  FIG. 13 , the touch panel control unit  204  executes the above-described pieces of processing. However, the present example embodiment is not limited thereto. Alternatively, the CPU  105  of the controller  100  illustrated in  FIG. 14  may be employed. In a case where the CPU  105  is employed, the processing in  FIG. 13  will be executed as follows. In this case, the operation unit  200  internally executes the above-described operation executed by the touch panel control unit  204 . 
     In step S 201 , the CPU  105  determines whether a capacitance of the sensor element  227  exceeds the threshold T 1  by the physical object  301  moving close to the operation panel  224 . In a case where the capacitance exceeds the threshold T 1  (YES in step S 201 ), the processing proceeds to step S 203 . In step S 201 , in a case where the capacitance does not exceed the threshold T 1  (NO in step S 201 ), the processing proceeds to step S 202 . 
     In step S 202 , the CPU  105  causes the operation unit  200  to display no pointer. The processing returns to step S 201  when the processing in step S 202  is ended. 
     In step S 203 , the CPU  105  instructs the operation unit  200  to display a pointer. Then, the processing proceeds to step S 204 . 
     In step S 204 , the operation unit  200  displays the pointer  318  on the display unit  209 . Then the processing proceeds to step S 205 . 
     In step S 205 , the CPU  105  determines whether a capacitance of the sensor element  227  exceeds the threshold T 2 . In a case where the capacitance exceeds the threshold T 2  (YES in step S 205 ), the processing proceeds to step S 206 . In step S 205 , in a case where the capacitance of the sensor element  227  does not exceed the threshold T 2  (NO in step S 205 ), the processing returns to step S 201 . 
     In step S 206 , the CPU  105  acquires coordinates of the sensor element  227  from the memory unit  220 , and instructs the operation unit  200  to invert color of a point corresponding to the coordinates. Then, the processing proceeds to step S 207 . 
     In step S 207 , the operation unit  200  receives the instruction for inverting the color of the point corresponding to the coordinates, and causes the display unit  209  to invert the color of the point corresponding to the coordinates. Then, the processing proceeds to step S 208 . 
     In step S 208 , the touch panel control unit  204  determines that the color inverted point corresponding to the coordinates is a position decided by the user, i.e., the touch panel control unit  204  determines that a touch operation is performed by the user. Then, the processing proceeds to step S 209 . 
     In step S 209 , the CPU  105  determines whether a capacitance of the sensor element  227  exceeds the threshold T 3 . In a case where the capacitance exceeds the threshold T 3  (YES in step S 209 ), the processing proceeds to step S 210 . The processing proceeds to step S 211  when the processing in step S 210  is ended. On the other hand, in a case where the capacitance does not exceed the threshold T 3  (NO in step S 209 ), the processing proceeds to step S 201 . 
     In step S 210 , the CPU  105  instructs the operation unit  200  to issue warnings. In step S 211 , as operation for issuing warnings, the operation unit  200  changes a background color of display, displays a warning message, and outputs a warning sound. The processing proceeds to step S 212  when the processing in step S 211  is ended. 
     In step S 212 , the CPU  105  determines whether the physical object  301  is in contact with the operation unit  200 . In a case where the physical object  301  is in contact with the operation unit  200  (YES in step S 212 ), the processing proceeds to step S 213 . In step S 213 , the CPU  105  registers an ID of the log-in user to track the ID through an information network, such as “COCOA” which is a cooperative checking system between users to check contact with a person infected with a coronavirus. Then, the processing proceeds to step S 214 . In step S 214 , the CPU  105  provides a notification of sterilization to the user. This notification of sterilization may be displayed on the operation unit  200 . 
     In the first and the second example embodiments, the non-contact type touch panels have been taken as examples. However, application of the configurations according to the first and the second example embodiments is not limited to the above described non-contact type touch panels, but to a system in which an operation unit is projected in the air, or an input is executed through a gesture motion. In both of the cases, a warning may be issued in a case where a user excessively moves the finger in an input direction. 
     Although various example embodiments of the present disclosure have been described as the above, the spirit and the scope of the present invention are not limited to specific descriptions of the present specification. 
     Other Embodiments 
     Embodiment(s) of the present disclosure can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)), a flash memory device, a memory card, and the like. 
     While example embodiments have been described, it is to be understood that the invention is not limited to the disclosed example embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2021-009131, filed Jan. 22, 2021, which is hereby incorporated by reference herein in its entirety.