Display device, display control method for display device, and display control program

Abstract

To provide a display apparatus configured to prompt a user to clean up a screen by allowing the user to visually recognize cleanup timing to clean up the screen in a display unit, a display control method for the display apparatus, and a display control program.SOLUTION: A multi-function printer, which is an example of a display apparatus, includes a display section with a screen and a controller that changes a display content of the screen. The multi-function printer includes the display section including an input section for input of a position on the screen as a contact position by a touch on the screen, and the controller that controls the display section. At least one of the factors indicating a degree of contamination of the screen since the previous screen cleanup is used as a parameter. In this case, the controller accumulates a value of at least one parameter since the previous screen cleanup (S11) and, in accordance with the accumulated value of the parameter, reduces a degree of visibility of a display content displayed on the screen (S12, S13, S16).SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a display device having a screen that allows input by touching, a display control method for the display device, and a display control program. [Background technology]

[0002] For example, Patent Document 1 discloses a printer (an example of a display device) equipped with a touch panel type operation panel. In this printer, the degree of completion of cleaning when a user cleans the screen is determined by the cumulative number of pixels touched, and cleaning is considered complete when a certain amount is exceeded.

[0003] Patent Document 2 discloses a printer (an example of a display device) that has a function to prevent malfunctions caused by accidentally operating other operation keys while cleaning. This printer has a hardware key that can disable the operation of other operation keys while cleaning. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-205012 A [Patent Document 2] Japanese Patent Application Publication No. 5-94248 Summary of the Invention [Problem to be solved by the invention]

[0005] However, while the printer described in Patent Document 1 above automatically determines the degree of completion of cleaning, it does not take into account the need for cleaning, and this technology can only be used when the user feels like cleaning.

[0006] In addition, in the printer described in Patent Document 2, the provision of hard keys improves ease of cleaning and the reliability of cleaning, as cleaning can be performed reliably without causing malfunctions; however, as with Patent Document 1, the timing of cleaning is left to the voluntary actions of the user.

[0007] As described above, the conventional technology has improved the ease and accuracy of cleaning, but the timing of cleaning is based on the user's own voluntary action. Although it is possible to notify the user of the timing of cleaning by text information on the touch panel using a timer or the like, this technology only expects the user to take voluntary action when they see the information. Therefore, there is a problem that even if the screen is dirty, if there is no problem with the visibility of the screen, the user may leave it without cleaning it. [Means for solving the problem]

[0008] A display device that solves the above problem is a display device having a display unit with a screen and a control unit that changes the display content of the screen, the display unit having an input unit that can input a position on the screen as a contact position by touching the screen, and the control unit that controls the display unit, and when at least one of the factors that represent the degree of contamination of the screen since the last time the screen was cleaned is used as a parameter, the control unit accumulates the value of at least one of the parameters since the last time the screen was cleaned, and reduces the visibility of the display content displayed on the screen in accordance with the accumulated value of the parameter.

[0009] A display control method for a display device that solves the above-mentioned problems is a display control method for a display device equipped with a display unit having a screen, the display device comprising: the display unit having an input unit for inputting a position on the screen as a contact position by touching the screen; and a control unit that controls the operation of the display unit, the control unit having a cleaning management mode as an operation mode of the display unit that prompts cleaning of the screen, the control unit, at least in the cleaning management mode, accumulates values ​​of at least one of the following parameters: the time elapsed since the last cleaning, the number of operations, the operation time, and the number of people approaching the multifunction device, and reduces the visibility of the display content of the display unit in accordance with the accumulated value of the parameter; and changes the visibility of the display content of the display unit to a higher level in accordance with the contact area detected when the screen is cleaned.

[0010] A display control program that solves the above problem is a display control program executed by a computer included in a display device equipped with a display unit having a screen, the display device comprising: a display unit having an input unit for inputting a position on the screen as a contact position by touching the screen; and a computer that controls the operation of the display unit, the computer having a cleaning management mode as an operation mode of the display unit that prompts cleaning of the screen, and causes the computer to execute, at least in the cleaning management mode, a step of accumulating values ​​of at least one of the following parameters: the time elapsed since the last cleaning, the number of operations, the operation time, and the number of people approaching the multifunction device, and reducing the visibility of the display content of the display unit in accordance with the accumulated value of the parameter; and a step of increasing the visibility of the display content of the display unit in accordance with the contact area detected when the screen is cleaned. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view showing a multifunction peripheral according to a first embodiment. [Diagram 2] FIG. 2 is a block diagram showing the electrical configuration of the multifunction peripheral. [Diagram 3]FIG. 4 is a schematic diagram showing a main screen displayed on the screen of a display unit. [Figure 4] FIG. 13 is a schematic diagram showing a main screen with a reduced degree of visibility. [Diagram 5] FIG. 13 is a schematic diagram showing the main screen with the lowest visibility. [Figure 6] 5A and 5B are schematic diagrams illustrating a display control process when cleaning the screen of the display unit. [Figure 7] 6 is a flowchart showing a first display control process. [Figure 8] 6 is a flowchart showing a first display control process. [Figure 9] FIG. 11 is a schematic diagram showing a state in which the visibility of a main screen displayed on a screen of a display unit is reduced in an example of a second embodiment. [Figure 10] FIG. 13 is a schematic diagram showing a state in which the visibility of the main screen is significantly reduced. [Figure 11] 5A and 5B are schematic diagrams illustrating a display control process when the main screen is wiped. [Figure 12] FIG. 13 is a schematic diagram showing a state in which the visibility of a main screen displayed on the screen of the display unit is reduced in another example of the second embodiment. [Figure 13] FIG. 13 is a schematic diagram showing a state in which the visibility of the main screen is significantly reduced. [Figure 14] 5A and 5B are schematic diagrams illustrating a display control process when the main screen is wiped. [Figure 15] FIG. 13 is a schematic diagram showing a state in which the visibility of a main screen displayed on the screen of a display unit in a third embodiment is reduced. [Figure 16] FIG. 13 is a schematic diagram showing a state in which the visibility of the main screen is significantly reduced. [Figure 17] 5A and 5B are schematic diagrams illustrating a display control process when the main screen is wiped. [Figure 18] FIG. 13 is a schematic diagram showing a state in which the visibility of a main screen displayed on the screen of a display unit in a fourth embodiment is reduced. [Figure 19] FIG. 13 is a schematic diagram showing a state in which the visibility of the main screen is significantly reduced. [Figure 20] 5A and 5B are schematic diagrams illustrating a display control process when the main screen is wiped. [Figure 21] FIG. 13 is a schematic diagram showing a state in which the visibility of a main screen displayed on a screen of a display unit in a fifth embodiment is reduced. [Figure 22] FIG. 13 is a schematic diagram showing a state in which the visibility of the main screen is significantly reduced. [Diagram 23] 5A and 5B are schematic diagrams illustrating a display control process when the main screen is wiped. [Figure 24] FIG. 23 is a schematic diagram showing a state in which the visibility of a main screen displayed on the screen of a display unit in a sixth embodiment is reduced. [Diagram 25] FIG. 13 is a schematic diagram showing a state in which the visibility of the main screen is significantly reduced. [Figure 26] 5A and 5B are schematic diagrams illustrating a display control process when the main screen is wiped. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An embodiment of a media reading device will now be described. Hereinafter, a multifunction machine 11, which is an embodiment of a display device, will be described with reference to the drawings. 1, the multifunction device 11 is placed on a horizontal plane and has a width direction Y, a depth direction X, and a vertical direction Z. The width direction Y and the depth direction X are perpendicular to the vertical direction Z. In addition, the side of the multifunction device 11 on which the display unit 15 is provided is the front.

[0013] <Configuration of multifunction device> As shown in Fig. 1, a multifunction device 11 as an example of a display device has a display unit 15 having a screen 16, and a control unit 20 that controls the display contents of the screen 16. The multifunction device 11 includes a main body 12 having a rectangular parallelepiped shape, and a reading unit 13 attached to the upper part of the main body 12. The display unit 15 is provided at the upper part of the main body 12. The display unit 15 is located closer to the front side in the depth direction X than the reading unit 13. The screen 16 of the display unit 15 is formed of, for example, a touch panel. Therefore, a user can give instructions to the multifunction device 11 by operating the screen 16.

[0014] The display unit 15 includes an operation unit 21 in a portion other than the screen 16. The operation unit 21 is configured with mechanical switches. Even when the display content of the screen 16 is turned off, the user can operate the operation unit 21 to give instructions to the multifunction device 11. The operation unit 21 includes, for example, a power switch.

[0015] The reading unit 13 shown in FIG. 1 reads an image of a document (not shown). The reading unit 13 includes a document table 13A on which a document is placed, and an automatic feed unit 14 for transporting the document. The automatic feed unit 14 includes a document tray 14A on which a document can be placed, and an edge guide 14B for positioning the document placed on the document tray 14A. The automatic feed unit 14 transports the documents placed on the document tray 14A one by one along a transport path (not shown) that passes through the reading unit 13. The reading unit 13 sequentially reads the documents transported by the automatic feed unit 14. The reading unit 13 has a feed-type reading function for reading the document transported by the automatic feed unit 14, and a flatbed-type reading function for reading the document placed on the document table 13A.

[0016] The entire main body 12 constitutes a printing section 17. The printing section 17 has multiple cassettes 18 in which media such as paper (not shown) are stored, and a discharge section 19 into which the printed media is discharged after printing is performed on the media transported from the cassettes 18. The discharge section 19 is recessed between the main body 12 and the reading section 13. The discharge section 19 has a discharge tray 19A on which the discharged media is placed.

[0017] The printing unit 17 incorporates within the main body 12 a transport unit (see Figure 2) that transports the medium along a transport path from the cassette 18 to the discharge tray 19A, and a recording head 23 (see Figure 2) that prints on the medium at a printing position along the transport path.

[0018] Furthermore, a plurality of display screens including a main screen MG (see FIG. 3) and sub-screens such as a selection screen are selectively displayed on a screen 16 of a display unit 15 provided on the main body 12. When the multifunction device 11 is in a power-on state and no printing is being performed, the main screen MG is normally displayed on the screen 16. The main screen MG is, for example, a menu screen.

[0019] <Electrical configuration of the multifunction printer> Next, the electrical configuration of the multifunction device 11 will be described with reference to FIG. The multifunction device 11 includes a control unit 20 , an operation unit 21 , a reading unit 13 , a printing unit 17 , a display unit 15 and a first sensor 25 .

[0020] The operation unit 21 is an operation unit that is made up of, for example, physical hard switches. An example of the operation unit is a power operation unit that turns the power of the multifunction device 11 on and off. The reading unit 13 is controlled by the control unit 20 and reads the original. The printing unit 17 includes a transport unit 22 and a recording head 23. The printing unit 17 is controlled by the control unit 20, and the recording head 23 records characters, images, etc. on the medium transported by the transport unit 22. For example, when a copy instruction is received, the control unit 20 makes the reading unit 13 read the original and makes the printing unit 17 print the image of the read original on the medium, thereby making a copy.

[0021] The display unit 15 includes a contact detection unit 24. The display unit 15 is configured with, for example, a touch panel. When the user touches the screen 16 (see FIGS. 1 and 3) with a finger, the contact detection unit 24 detects the coordinates of the contact position.

[0022] The first sensor 25 detects a person approaching the multifunction device 11 since the previous cleaning. The first sensor 25 is, for example, a human presence sensor. The multifunction device 11 may also include a second sensor 26 as an example of a detection unit capable of detecting the values ​​of environmental parameters around the multifunction device 11. The second sensor 26 detects at least one of the temperature, humidity, amount of dust, amount of oil in the environment surrounding the multifunction device 11, and the body temperature of an operator operating the screen 16 of the display unit 15.

[0023] The control unit 20 includes a computer 30. The computer 30 is configured with, for example, a microprocessor. When the contact detection unit 24 detects contact at a position within the range of an input unit 50 (see FIG. 3) displayed on the screen 16, the computer 30 detects that the input unit 50 associated with that coordinate range has been operated.

[0024] The computer 30 includes a first timing unit 31, a second timing unit 32, a first counter 33, a second counter 34, a display control unit 35, and a memory unit 36. The display control unit 35 includes an operation detection unit 41 and a touch position detection unit 42. Based on the coordinate values ​​input from the contact detection unit 24 that detects the position where the user operates (touches) the screen 16, the operation detection unit 41 detects that the touch on the screen 16 is an operation by the user if the coordinate values ​​are within the coordinate range of the input unit 50 (FIG. 3).

[0025] The contact position detection unit 42 detects the position where the user touches the screen 16 based on the coordinate values ​​input from the contact detection unit 24. For example, when the user touches the screen 16 of the display unit 15 to wipe the screen 16 in order to clean it, the contact position detection unit 42 detects the movement of the coordinates touched for the wiping. Therefore, the computer 30 can detect the position where the user wiped the screen 16 (wiping trajectory) by the contact position detection unit 42.

[0026] The storage unit 36 ​​stores a program PR, a first threshold value SV1, a second threshold value SV2, a first image data ID1, and a second image data ID2. The program PR includes a first program for a first display control process shown in a flowchart in FIG. 7, and a second program for a second display control process shown in a flowchart in FIG. 8. The first threshold value SV1 is used in the first display control process, and the second threshold value SV2 is used in the second display control process. The first image data ID1 is image data of the display contents to be displayed on the screen 16. The first image data ID1 includes image data for displaying a display screen such as the main screen MG shown in FIG. 3. The second image data ID2 is image data used to reduce the visibility of the display contents to be displayed on the screen 16. The second image data ID2 is used in place of the first image data ID1, or is used to superimpose an image for reducing the visibility on a display screen based on the first image data ID1.

[0027] The first program and the second program constituting the program PR may be stored in a storage medium and installed in the multifunction device 11. In this case, the storage medium storing the first program and the second program may be an accessory included with the multifunction device 11 when it is purchased, or may be purchased together with the multifunction device 11. The storage medium may be, for example, a storage disk such as a magnetic disk or an optical disk, a portable memory such as a USB memory, or an external storage device of an external type.

[0028] <Screen display content> Here, the display contents displayed on the screen 16 of the display unit 15 by the display control unit 35 will be described with reference to Fig. 3. Fig. 3 shows a main screen MG, which is an example of the display contents displayed on the screen 16 of the display unit 15.

[0029] As shown in FIG. 3, the display unit 15 has an input unit 50 that can input a position on the screen 16 as a contact position by touching the screen 16. In the example shown in FIG. 3, the input unit 50 is, for example, an operation button. More specifically, the main screen MG, which is a menu screen, includes a print button 51, a scan button 52, and a copy button 53 as the input unit 50. When the user touches any of these buttons 51 to 53, the screen is switched to a sub-screen, which is a lower-level screen corresponding to the touched button. More specifically, when the user touches and operates the print button 51, the screen is switched to a print setting screen (not shown). When the user touches and operates the scan button 52, the screen is switched to a scan setting screen (not shown). When the user touches and operates the copy button 53, the screen is switched to a copy setting screen (not shown).

[0030] The main screen MG also includes operation buttons 54, 55 as the input unit 50. The operation buttons 54, 55 are configured by an instruction button operated to give an instruction to the multifunction device 11, or a switching button operated to switch to another sub-screen (not shown) that is a lower screen of the main screen MG. The operation buttons 54, 55 may also be a shutdown button, a selection button, or the like.

[0031] Other sub-screens include, for example, a maintenance screen operated when performing maintenance, and a setting registration screen operated to register various settings. Note that sub-screens not shown also constitute an example of the display contents. In this way, in this example, the display contents of screen 16 include a plurality of display screens. The display contents of screen 16 are switched to one of the plurality of display screens. Note that the hierarchy of sub-screens with respect to main screen MG is not limited to two hierarchical levels, and may be three or four or more hierarchical levels. Also, a configuration without sub-screens is possible.

[0032] The multifunction device 11 has a cleaning management mode that prompts the user to clean the screen 16 as an operation mode of the display unit 15. The multifunction device 11 may be configured to be able to switch the cleaning management mode on and off. For example, an operation button for switching the cleaning management mode on and off may be provided on the main screen MG. The multifunction device 11 may also be connected to a host device communicably via a network. The cleaning management mode may be switched on and off by operating an input operation unit such as a keyboard or mouse of the host device. The host device is communicably connected to the multifunction device 11 so that multiple users who use the multifunction device 11 can give instructions for printing or document reading. The host device may be a personal computer, a tablet PC, a mobile phone, a smartphone, or the like. The cleaning management mode is not limited to a configuration that allows it to be switched on and off, and may be a mode that is always activated when the multifunction device 11 is powered on.

[0033] Also, in Fig. 3, a message MS is displayed. The message MS may be a message that informs the user of the operating status of the multifunction device 11, a message that prompts the user to operate, or a message that informs the user of an operating method. Messages that inform the user of the operating status include messages that inform the user that printing, scanning, or copying is in progress. In Fig. 3, the message MS is shown as an alphabetical character string as an example, but the message MS may be in any language.

[0034] Furthermore, the main screen MG, which is one of the display screens, includes a background BG. Since the background BG is not the input unit 50, even if the user touches an area of ​​the background BG, it is not detected as an operation. The message MS is displayed superimposed on the background BG (for example, the layer of the background GR) so as to be superimposed on the front side. Note that a keyboard may be displayed on the screen 16 to allow input of characters and character strings. In this case, the keyboard displayed on the screen 16 is an example of an input unit.

[0035] The multifunction device 11 has a cleaning management mode that changes the display content to encourage the user to clean the screen 16. The multifunction device 11 of this embodiment performs a first display process in the cleaning mode that reduces the visibility of the display content to encourage the user to clean the screen 16. When cleaning the screen 16, the user operates the operation unit 21 or a predetermined input unit 50 on the screen to put the multifunction device 11 into the cleaning execution mode. This mode is managed by the control unit 20. As described above, the multifunction device 11 of this embodiment can switch the cleaning mode on and off. For example, when a user or a serviceman operates the operation unit 21 or a predetermined input unit 50 on the screen 16, the control unit 20 displays a switching screen (not shown) on the screen 16 for switching the cleaning mode on and off. Based on an operation signal by which the user selects either on or off on this switching screen, the control unit 20 switches the cleaning mode on and off.

[0036] In the cleaning mode, the multifunction device 11 of this embodiment performs a first display control process for lowering the visibility of the display contents so as to encourage the user to clean the screen 16. At least one of the factors representing the degree of contamination of the screen 16 since the previous cleaning of the screen is set as a parameter. The control unit 20 accumulates the value of the at least one parameter since the previous cleaning of the screen, and reduces the visibility of the display content displayed on the screen 16 according to the accumulated value of the parameter. Here, in this embodiment, the parameter can also be said to be at least one factor that brings the timing for the next cleaning of the screen 16 closer as the accumulated value since the previous cleaning of the screen 16 is larger.

[0037] During execution of the first display control process, the control unit 20 calculates the cumulative value of a parameter value indicating the degree of contamination of the screen 16, and reduces the visibility of the display content of the screen 16 in a stepwise or continuous manner according to the cumulative value of the parameter.

[0038] The at least one parameter includes at least one of the following: the time elapsed since the previous cleaning, the number of operations performed by touching the screen since the previous cleaning, the operation time, and the number of people approaching the multifunction device 11 since the previous cleaning.

[0039] The parameters that indicate the degree of contamination include the following: (a) Time since last screen cleaning. (b) the number of operations that have been performed by touching the screen since the last time the screen was cleaned; (c) The duration of operation since the last screen cleaning. (d) The number of people who have approached the MFP 11 since the last time the screen was cleaned. At least one of these (a) to (d) is set as a parameter. The parameter may be one, or two or three selected from (a) to (d), or all four. Here, the degree of contamination includes not only the degree of dirt on the screen 16, but also the degree of contamination of the screen 16 by viruses, bacteria, etc.

[0040] The control unit 20 of this embodiment is configured to be able to obtain the cumulative values ​​for all of these four parameters. The first timing unit 31 measures the time that has elapsed since the previous screen cleaning. The first timing unit 31 measures the time that has elapsed since the previous cleaning by counting the number of clock pulses from a clock circuit (not shown) in the computer 30, or the number of timing pulses or pulse edges generated from the clock pulses.

[0041] The second timer 32 measures the operation time during which the screen 16 has been operated since the previous screen cleaning. The second timer 32 counts the number of pulses or the number of pulse edges of clock pulses from a clock circuit (not shown) in the computer 30 or timing pulses generated from the clock pulses during a period during which an operation on the screen 16 is detected. This operation time is the cumulative value (cumulative time) of the operation time during which the screen 16 has been operated since the previous cleaning.

[0042] The first counter 33 counts the number of times that the screen 16 has been touched and operated since the previous screen cleaning. Here, the operation refers to the number of times that the input unit 50, which is an area of ​​the screen 16 where the user can input instructions to the multifunction device 11, has been operated. The number of operations can also be said to be the number of times that the control unit 20 has accepted inputs made by the user operating the input unit 50.

[0043] The second counter 34 counts the number of people who have approached the multifunction device 11 since the previous screen cleaning. The control unit 20 performs an increment process to increase the value of the second counter 34 by one every time the first sensor 25 detects a person.

[0044] The computer 30 in the control unit 20 performs a first display control process by executing a first program shown in the flowchart of Fig. 7 out of the programs PR stored in the storage unit 36. The computer 30 also performs a second display control process by executing a second program shown in the flowchart of Fig. 8 out of the programs PR stored in the storage unit 36.

[0045] The first threshold value SV1 is used in a first display control process for gradually or continuously decreasing the visibility of the display contents from the initial state (see FIG. 3). In the first display control process of this example, the visibility of the display contents is gradually decreased from the initial state. The first threshold value SV1 is reference data including a plurality of threshold values ​​consisting of a plurality of different numerical values. The first threshold value SV1 is used in the order of the reference data from the smallest value. When the cumulative value of the parameter exceeds the first threshold value SV1, the control unit 20 decreases the visibility of the display contents displayed on the screen 16 by one step. As the cumulative value of the parameter increases, the control unit 20 sequentially performs this process on the plurality of first threshold values ​​SV1 with different values, thereby gradually decreasing the visibility of the display contents on the screen 16.

[0046] The second threshold value SV2 is used in the second display control process in the cleaning execution mode to clean the screen 16 where the visibility of the display content has decreased, thereby increasing the visibility of the display content. In the second display control process of this example, the visibility of the display content is increased stepwise until it returns to the initial state. The second threshold value SV2 is reference data consisting of a plurality of numerical values ​​with different values. The second threshold value SV2 consisting of numerical values ​​with different values ​​is used in ascending order of values.

[0047] Next, the display control process executed by the computer 30 will be described with reference to Figs. 4 to 6. The control of the display contents of the screen 16 of the display unit 15 performed by the control unit 20 is specifically executed by the computer 30 in the control unit 20. The computer 30 executes the display control process by executing a program PR stored in the storage unit 36. The program PR includes a first display control process program shown in the flow chart of Fig. 7 and a second display control process program shown in the flow chart of Fig. 8.

[0048] Next, the cleaning management mode and the cleaning execution mode will be described. When the cleaning management mode is on, the multifunction device 11 reduces the visibility of the display contents displayed on the screen 16 of the display unit 15. When the cleaning execution mode is on, the multifunction device 11 can increase the visibility of the display contents displayed on the screen 16 of the display unit 15. Therefore, when the visibility of the display contents on the screen 16 decreases in the cleaning management mode, the user cleans the screen 16 to increase the visibility of the display contents. Therefore, in the cleaning management mode, the control unit 20 can encourage the user to clean the screen 16 at an appropriate cleaning timing by reducing the visibility of the display contents on the screen 16 as the contamination of the screen 16 progresses.

[0049] <Cleaning Management Mode> First, the cleaning management mode will be described. In this embodiment, the control unit 20 reduces the visibility of the display contents on the screen 16 based on the accumulated value of the parameter in the cleaning management mode. In detail, the control unit 20 reduces the visibility of the display contents when the accumulated value of the parameter exceeds a threshold value. In this embodiment, the control unit 20 reduces the visibility of the display contents by one step each time the accumulated value of the parameter exceeds the first threshold value SV1. The control unit 20 switches the first threshold value SV1 to a value one step larger each time the accumulated value of the parameter exceeds the first threshold value SV1. In this way, the control unit 20 gradually reduces the visibility of the display contents as the accumulated value of the parameter increases. Note that the first threshold value SV1 may be only one, and the display contents with different visibility levels may be switched in two steps.

[0050] The multifunction device 11 may include a threshold change operation unit operated by a user to change the threshold. In this example, one of the operation buttons 54, 55, which are the input unit 50, corresponds to an example of the threshold change operation unit. For example, one of the operation buttons 54, 55 in the main screen MG shown in FIG. 3 corresponds to an example of the threshold change operation unit. For example, assuming that the operation button 55 is an example of the threshold change operation unit, when the user touches and operates the operation button 55, a threshold change screen (not shown) is displayed as a sub-screen. The user changes the first threshold SV1 by performing a touch operation on the threshold change screen. In addition, the operation unit 21, which is a mechanical switch, may be an example of the threshold change operation unit. Furthermore, the first threshold SV1 may be changed by operating the input operation unit of the host device. A plurality of values ​​are set for the first threshold SV1 at regular intervals. For example, the user can change the minimum value of the first threshold SV1 and the regular interval of the first threshold SV1.

[0051] The control unit 20 obtains an overall cumulative value of the multiple parameters using a conversion formula between the multiple parameters, and determines whether the cumulative value exceeds a threshold value. Here, multiple parameters may be used. The cumulative values ​​of the multiple parameters are a, b, c..., and the coefficients according to the contribution of each parameter are A, B, C.... The cumulative value obtained by converting the cumulative values ​​of the multiple parameters into a single value is calculated as the sum of the values ​​obtained by multiplying the cumulative values ​​of each parameter by the coefficient. In other words, the cumulative value F of the parameters is calculated as F=A*a+B*b+C*c+....

[0052] For example, an elapsed time of "1 hour" and a number of operations of "1 time" are evaluated equally. In this case, the coefficients of the elapsed time parameter and the number of operations parameter are set to the same value. Also, the number of people approaching the multifunction device 11 of "5 people" and a number of operations of "1 time" are evaluated equally. In this case, the coefficient multiplied by the parameter of the number of operations is set to 5 times the coefficient multiplied by the parameter of the number of people approaching the multifunction device 11.

[0053] Furthermore, the control unit 20 may correct the accumulated value of the parameter by multiplying the accumulated value by a coefficient according to the detection value obtained by the second sensor 26, or may change the first threshold value SV1, which is an example of a threshold value, based on the detection value obtained by the second sensor 26. In more detail, the control unit 20 may correct the accumulated value of the parameter based on at least one of the temperature, humidity, amount of dust, amount of oil, and body temperature of the operator, which are the detection values ​​of the second sensor 26. Alternatively, the control unit 20 may correct the first threshold value SV1 based on at least one of the temperature, humidity, amount of dust, amount of oil, and body temperature of the operator, which are the detection values ​​of the second sensor 26.

[0054] In this embodiment, when the cleaning management mode is on, the computer 30 in the control unit 20 executes a first display control program shown in the flowchart of Fig. 7. As a result, the computer 30 performs a first display control process that gradually or continuously reduces the visibility of the display content on the screen 16 as the contamination of the screen 16 progresses.

[0055] <Cleaning execution mode> In this embodiment, in the cleaning execution mode, the control unit 20 increases the visibility of the display content on the screen 16 based on the area of ​​the cleaning area WA (see FIG. 6), which is the wiping area where the user wipes the screen 16. In detail, the control unit 20 increases the visibility of the display content by one step each time the cleaning area, which is the area of ​​the cleaning area WA, exceeds the second threshold value SV2. The control unit 20 switches the second threshold value SV2 to a value one step larger each time the cleaning area exceeds the second threshold value SV2. In this way, as the cleaning area increases, the control unit 20 gradually increases the visibility of the display content until it returns to the initial state.

[0056] The second threshold value SV2 may be configured to be variable by a user's input operation. For example, the user can change the second threshold value SV2 by operating one of the operation unit 21, the operation buttons 54 and 55 on the screen 16, or the input operation unit of the host device. The second threshold value SV2 is set to a plurality of values ​​at regular intervals, for example. The user can change, for example, the minimum value of the second threshold value SV2 and the regular interval of the second threshold value SV2.

[0057] In this embodiment, the computer 30 in the control unit 20 executes a second display control program shown in the flowchart of FIG. 8 when the cleaning execution mode is on. As a result, when the cleaning of the screen 16 is performed, the control unit 20 returns the visibility to the initial state shown in FIG. 3. In this embodiment, the control unit 20 increases the visibility stepwise or continuously as the cleaning of the screen 16 progresses. In detail, the computer 30 performs a second display control process that increases the visibility of the display content of the screen 16 stepwise or continuously until it returns to the initial state as the wiping of the screen 16 progresses. Also, in this embodiment, the control unit 20 increases the visibility of the area of ​​the screen 16 where cleaning has been completed. At this time, the control unit 20 acquires the position where the user has wiped (cleaned) the screen 16 based on the detection signal from the contact detection unit 24, and recognizes the area where cleaning has been completed from the acquired wiping position.

[0058] <Operation of the embodiment> Next, the operation of the multifunction device 11 of this embodiment will be described. The following describes the first display control process and the second display control process executed by the computer 30 of the control unit 20. When the computer 30 is in the cleaning management mode with the power on, it executes the first display control process shown in the flowchart of Fig. 7. The first display control process will be described below with reference to Figs. 3 to 5 and 7.

[0059] First, in step S11, the computer 30 counts the parameter values ​​from the previous cleaning. For example, the first timer 31 counts the elapsed time from the previous cleaning. The second timer 32 counts the operation time of the screen 16 from the previous cleaning. The first counter 33 counts the number of times the screen 16 has been touched and operated since the previous cleaning. The second counter 34 counts the number of people who have approached the multifunction device 11 since the previous cleaning. In this example, the computer 30 counts four parameters. The storage unit 36 ​​may store a first threshold value SV1 for each parameter, or may store a first threshold value SV1 for a cumulative value obtained by converting the count values ​​of multiple parameters into one cumulative value using a conversion formula using a weighting coefficient for each parameter. Note that, although the at least one parameter is multiple parameters in the example shown in FIG. 2, the parameter may be only one. In this case, the single parameter may be any one of the following: the time elapsed since the previous cleaning, the operation time since the previous cleaning, the number of operations since the previous cleaning, and the number of people approaching the multifunction device 11 since the previous cleaning. Also, the parameters may be two or three of the following: the time elapsed since the previous cleaning, the operation time, the number of operations, and the number of people approaching the multifunction device 11.

[0060] In step S12, the computer 30 judges whether the count value of the parameter exceeds the first threshold value. For example, if there is one parameter, it judges whether the count value (accumulated value) of the one parameter exceeds the first threshold value SV1. If there are two or more parameters, it judges whether the accumulated value obtained by converting the count values ​​(accumulated values) of the multiple parameters into one accumulated value using a conversion formula exceeds the first threshold value SV1. If the count value of the parameter does not exceed the first threshold value SV1, it returns to the process of step S11, and repeats the counting process in step S11 until it is judged in step S12 that the count value of the parameter exceeds the first threshold value SV1. On the other hand, if it is judged that the count value of the parameter exceeds the first threshold value SV1, it proceeds to step S13.

[0061] In step S13, the computer 30 reduces the visibility of the display content. For example, the display density is reduced from the display content of the screen 16 shown in Fig. 3 to the display content of the screen 16 shown in Fig. 4, thereby reducing the visibility of the display content of the screen 16.

[0062] In step S14, the computer 30 determines whether or not the cleaning execution mode has been turned on. If the cleaning execution mode has been turned on, the routine ends. If the cleaning execution mode has not been turned on, the computer 30 proceeds to step S15.

[0063] In step S15, computer 30 determines whether an initialization operation has been performed. Here, the initialization operation is an operation for forcibly returning the display contents of screen 16 to the initial state shown in Fig. 3 even if screen 16 is not cleaned in the cleaning execution mode. If an initialization operation has been performed, the process proceeds to step S17, and if not, the process proceeds to step S16.

[0064] In step S16, the computer 30 switches the first threshold value to a value one step larger. That is, since the count value (accumulated value) of the parameter exceeds the first threshold value SV1 in step S12 and is a value larger than the first threshold value SV1 up to that point, the computer 30 changes the first threshold value SV1 to a value one step larger than the current count value.

[0065] In step S17, the computer 30 returns the display screen to its initial state. That is, when the computer 30 receives an initialization operation from the user, it returns the display screen, which is the display content of the screen 16, to its initial state.

[0066] After switching the first threshold value SV1 to a value one step larger in step S16, the computer 30 returns to the process of step S11. Thereafter, the computer 30 repeats the processes of steps S11 to S16. As a result, the display density becomes lighter from the display content of the screen 16 shown in FIG. 4 to the display content of the screen 16 shown in FIG. 5, and the visibility of the display content of the screen 16 further decreases. In this way, as the contamination of the screen 16 progresses, the display density of the display area (e.g., the main screen MG) on the screen 16 becomes lighter in stages, and the visibility of the display content of the screen 16 decreases in stages. Note that, although the visibility of the display content displayed on the screen 16 is decreased in stages in this example, it may be decreased continuously.

[0067] In this way, the visibility of the display contents on the screen 16 gradually decreases, and at a certain point in time, the user cleans the screen 16 to eliminate the difficulty in viewing the display contents due to the low visibility. To clean the screen 16, the user performs an ON operation to turn on the cleaning execution mode. As a result, the computer 30 determines in step S14 that an ON operation has been performed, and ends the routine. With the end of this routine, the mode transitions from the cleaning management mode to the cleaning execution mode. When the mode transitions to the cleaning execution mode, the computer 30 executes a second display control process shown in FIG. 8.

[0068] The processing of steps S11, S12, S13, and S16 in FIG. 7 corresponds to an example of the processing of "accumulating the values ​​of at least one of the parameters of the time elapsed since the previous cleaning, the number of operations, the operation time, and the number of people approaching the multifunction device 11, at least in the cleaning management mode, and reducing the visibility of the display content of the display unit in accordance with the accumulated value of the parameter (or step)."

[0069] Next, the second display control process will be described with reference to FIG. 3, FIG. 6, FIG. 8, etc. When the user cleans the screen 16, the user switches the multifunction device 11 to the cleaning execution mode by operating one of the operation unit 21, the operation buttons 54, 55, and the input operation unit of the host device. When the cleaning execution mode is turned on, the computer 30 makes the input unit 50 on the display screen of the screen 16 inoperable. Therefore, even if the user wipes the screen 16 with a cleaning cloth or the like, the input unit 50 will not be operated. Hereinafter, in the cleaning execution mode, as the user wipes the screen 16, the visibility of the display contents displayed on the screen 16 increases stepwise or continuously. The processing of the display contents when the user wipes the screen 16 is performed by the computer 30 executing the second cleaning control process shown in the flowchart of FIG. 8. Hereinafter, the second display control process will be described with reference to FIG. 8.

[0070] First, in step S21, computer 30 detects a cleaning area on the screen. When a user wipes screen 16, the cleaning area, which is the wiping area on screen 16, is detected by contact detection unit 24. That is, computer 30 detects the cleaning area based on the contact position detected by contact detection unit 24 of display unit 15. Here, computer 30 counts the number of pixels on screen 16 of display unit 15 where contact is detected, to obtain the area of ​​the cleaning area (e.g., the number of pixels).

[0071] In step S22, the computer 30 determines whether the area of ​​the cleaning area WA exceeds the second threshold value SV2. If the area of ​​the cleaning area WA does not exceed the second threshold value SV2, the computer 30 returns to step S21, and continues detecting the cleaning area WA on the screen 16 until the area of ​​the cleaning area WA exceeds the second threshold value SV2 in step S22. Then, if the area of ​​the cleaning area WA exceeds the second threshold value SV2, the computer 30 proceeds to step S23.

[0072] In step S23, the computer 30 increases the visibility of the display contents. For example, the computer 30 increases the visibility of the display contents by one level. Before the transition to the cleaning mode, the visibility was reduced by the background BG of the display contents and the density of the characters becoming lighter as shown in FIG. 4 and FIG. 5. As shown in FIG. 6, the visibility of the cleaning area WA of the screen 16 that the user has finished cleaning by wiping increases. Therefore, the user can recognize the area of ​​the screen 16 that has been cleaned. In addition, in the cleaning mode, the input unit 50 of the display contents of the screen 16 is in an inactive operation state in which touching is not detected as an operation. Therefore, even if the user touches the input unit 50 during the wiping process, the touch is not detected as an operation. Therefore, it is possible to suppress the occurrence of erroneous operations caused by the user touching the input unit 50 with a finger or a wiping cloth when cleaning the screen 16. In addition, when the user wipes the screen 16, as shown in FIG. 6, the wiping unit 56 that moves following the wiping path of the user is displayed on the screen 16. In addition, the cleaning execution mode that renders operations inactive may be eliminated by using a material or surface treatment for the wiping cloth used for cleaning that does not detect contact with the screen 16 even if the cloth comes into contact with the screen 16.

[0073] In step S24, computer 30 judges whether the initial state has been restored. If the initial state has not been restored, the process proceeds to step S25, and if the initial state has been restored, the process proceeds to step S26. During the intermediate stage of cleaning from when the user starts cleaning screen 16 until wiping the entire screen 16, only a portion of the display content of screen 16 is in the cleaning area WA as shown in FIG. 6, and the display content is not in the initial state as shown in FIG. 3. Therefore, during the intermediate stage of cleaning, computer 30 proceeds to the process of step S25.

[0074] In step S25, the computer 30 switches the second threshold to a value one step larger. That is, since the area (e.g., the number of pixels) of the cleaning area WA exceeds the second threshold SV2 in step S22 and is a value larger than the previous second threshold SV2, the computer 30 changes the second threshold SV2 to a value one step larger than the current area of ​​the cleaning area WA.

[0075] After switching the second threshold value SV2 to a value one step larger in step S25, the computer 30 returns to the process of step S21. Thereafter, the computer 30 repeats the processes of steps S21 to S25. As a result, as the user progresses with cleaning of the screen 16, the cleaning area WA that has returned to a high visibility level increases stepwise as shown in Fig. 6. Note that, in this example, the cleaning area WA of the screen 16 that has returned to a high visibility level by wiping is increased stepwise, but it may also be increased continuously.

[0076] In this way, the cleaning area WA that has returned to a high degree of visibility on the screen 16 increases, allowing the user to recognize that cleaning of the entire screen 16 has been completed at a certain point. When the user finishes cleaning the screen 16, the user performs an end operation to end the cleaning execution mode. For example, the user performs an end operation of the cleaning execution mode by operating one of the operation unit 21, the operation buttons 54 and 55 on the screen 16, or the input operation unit of the host device.

[0077] In step S26, the computer 30 determines whether or not an operation to end the cleaning mode has been performed. If an operation to end the cleaning mode has not been performed, the computer 30 waits until the operation to end the cleaning mode is performed. If the computer 30 determines that an operation to end the cleaning mode has been performed, the computer 30 proceeds to step S27.

[0078] In step S27, the computer 30 ends the cleaning execution mode. Since the user may forget to end the cleaning execution mode, the computer 30 forcibly ends the cleaning execution mode if the user does not accept an operation to end the cleaning execution mode even after a certain period of time has elapsed after the display content has returned to the initial state. By ending the cleaning execution mode in this way, the multifunction device 11 returns to the cleaning management mode.

[0079] The processes of steps S21, S22, S23, and S25 in FIG. 8 correspond to an example of the process of "increasing the visibility of the display content on the display unit according to the contact area detected by cleaning the screen (or steps)."

[0080] According to the first embodiment, the following effects can be obtained. (1-1) The multifunction device 11, which is an example of a display device, has a display unit 15 having a screen 16 and a control unit 20 that changes the display content of the screen 16. The multifunction device 11 includes the display unit 15 having an input unit 50 that can input a position on the screen 16 as a contact position by touching the screen 16, and the control unit 20 that controls the display unit 15. At least one of the factors that indicate the degree of contamination of the screen 16 since the previous screen cleaning is set as a parameter. In this case, the control unit 20 accumulates the value of at least one parameter since the previous screen cleaning, and reduces the visibility of the display content displayed on the screen 16 according to the accumulated value of the parameter. According to this configuration, the visibility of the display content is reduced based on the accumulated value of at least one parameter accumulated since the previous screen cleaning, so that the reduced visibility can urge the user to voluntarily clean the screen 16. Therefore, the frequency with which the screen 16 is left uncleaned can be reduced.

[0081] (1-2) The at least one parameter includes at least one of the following: the time elapsed since the previous screen cleaning, the number of operations performed by touching screen 16 since the previous screen cleaning, the operation time, and the number of people approaching the display device since the previous screen cleaning. According to this configuration, since at least one of the time elapsed since the previous screen cleaning, the number of operations, the operation time, and the number of people approaching the display device is used as a parameter, it is possible to encourage the user to voluntarily clean screen 16 at an appropriate cleaning timing.

[0082] (1-3) The decrease in visibility is caused by changing the display density. According to this configuration, the visibility decreases by changing the display density on the screen 16, which makes it easier to encourage the user to clean the screen 16 voluntarily.

[0083] (1-4) The control unit 20 returns the visibility to the initial state when cleaning of the screen 16 is performed. According to this configuration, the visibility is returned to the initial state when cleaning of the screen 16 is performed, which makes it easier to encourage cleaning.

[0084] (1-5) The control unit 20 increases the visibility stepwise or continuously as the cleaning of the screen 16 progresses. According to this configuration, the visibility increases as the cleaning of the screen 16 progresses, making it easy to recognize the progress of cleaning.

[0085] (1-6) The control unit 20 increases the visibility of the area on the screen 16 where cleaning has been completed. This configuration allows the user to recognize the progress of cleaning on the screen 16. For example, it is less likely that cleaning will be left undone.

[0086] (1-7) The control unit 20 has a cleaning management mode that prompts the user to clean the screen 16. When the cleaning management mode is on, the control unit 20 executes a process of lowering the visibility of the display content according to the accumulated value of the parameter. The multifunction device 11 is configured to be able to switch the cleaning management mode on and off. With this configuration, the user can select to prompt the user to clean the screen 16 when desired.

[0087] (1-8) The control unit 20 reduces the visibility of the display content when the cumulative value of the parameter exceeds a threshold value. With this configuration, the visibility of the display content can be reduced in stages according to the cumulative value of the parameter. For example, the processing load of the control unit 20 can be reduced.

[0088] (1-9) The multifunction device 11 includes a threshold change operation unit that is operated by the user to change the threshold. With this configuration, the user can change the threshold by operating the threshold change operation unit, and can adjust the speed at which the visibility is reduced. This makes it possible to prompt the user to clean the screen 16 at a more appropriate time.

[0089] (1-10) The control unit 20 obtains an overall cumulative value of the multiple parameters using a conversion formula between the multiple parameters, and judges whether the cumulative value exceeds a threshold value. With this configuration, the overall cumulative value of the multiple parameters is appropriately obtained using the conversion value, so that the degree of contamination of the screen 16 can be appropriately evaluated based on multiple factors. Therefore, the user can be prompted to clean the screen 16 at a more appropriate time.

[0090] (1-11) The multifunction device 11 includes a detection unit that detects at least one of the temperature, humidity, amount of dust, amount of oil in the surrounding environment, and the body temperature of the operator. The accumulated value of the parameter is corrected by multiplying the accumulated value by a coefficient according to the amount of detection obtained by the detection unit, or the threshold value is changed based on the detection value obtained by the detection unit. According to this configuration, the degree of contamination of the screen 16 is evaluated based on the accumulated value that takes into account at least one of the temperature, humidity, amount of dust, amount of oil in the surrounding environment, and the body temperature of the operator. Therefore, cleaning of the screen 16 can be promoted at a more appropriate timing.

[0091] (1-12) In a display control method for a display device including a display unit 15 having a screen 16, the control unit 20 performs the following (A) and (B). (A) In at least the cleaning management mode, the control unit 20 accumulates parameter values ​​using at least one of the time elapsed since the previous cleaning, the number of operations, the operation time, and the number of people approaching the multifunction device as a parameter, and reduces the visibility of the display content of the display unit 15 according to the accumulated parameter value. (B) In accordance with the contact area detected by cleaning the screen 16, the visibility of the display content of the display unit 15 is increased. According to this display control method, as with the multifunction device 11, which is an example of a display device, it is possible to reduce the frequency with which the screen 16 is left uncleaned.

[0092] (1-13) A display control program executed by the computer 30 included in a display device having a display unit 15 with a screen 16 causes the computer 30 to execute the following steps A and B. Step A: In at least the cleaning management mode, the computer 30 accumulates parameter values ​​using at least one of the following parameters: the time elapsed since the previous cleaning, the number of operations, the operation time, and the number of people approaching the multifunction device 11, and reduces the visibility of the display content of the display unit 15 according to the accumulated parameter value. Step B: The visibility of the display content of the display unit 15 is increased according to the contact area detected by cleaning the screen 16. According to this display control program, it is possible to reduce the frequency with which the screen 16 is left uncleaned, similar to the multifunction device 11, which is an example of a display device.

[0093] Second embodiment Next, a second embodiment will be described with reference to Figures 9 to 14. Note that the basic configuration and electrical configuration of the multifunction device 11 are similar to those of the first embodiment, so the following will describe points that are particularly different from the first embodiment.

[0094] The control unit 20 reduces the visibility of the display content at a position on the screen 16 corresponding to the operation position by the user. In the first embodiment, the visibility of the entire display content of the screen 16 is reduced stepwise or continuously. In contrast, in the second embodiment, the visibility of the display content is partially reduced at a position on the main screen MG, which is the display content of the screen 16, corresponding to the operation position touched by the user. In the first embodiment, the visibility is reduced by changing the display density. In contrast, in the second embodiment, the visibility is reduced by displaying an obstacle.

[0095] Specifically, as shown in Fig. 9, a process is performed to display an obstacle 61 at a position on the screen 16 corresponding to the operation position by the user. In Fig. 9, an obstacle 61, for example a fallen leaf, is displayed at a position corresponding to the operation position by the user. Therefore, the obstacle 61 is displayed at the position where the user touches the screen 16 with his / her finger to operate the input unit 50. As a result, the visibility of the main screen MG, which is the display content of the display unit 15, decreases.

[0096] 10, the number of obstacles 61 on the screen 16 increases stepwise as the cumulative value of at least one of the parameters, which is the time elapsed since the last screen cleaning, the number of user operations since the last screen cleaning, the operation time, and the number of people approaching the multifunction device 11 since the last screen cleaning, increases. For the user, the greater the number of obstacles 61 on the screen 16, the lower the visibility of the main screen MG, which is the display content. This lowering of the visibility of the display content on the screen 16 prompts the user to clean the screen 16.

[0097] When the user's visibility of the display content displayed on screen 16 decreases, the user cleans screen 16 at a certain timing, thereby returning the visibility of the display content on screen 16 to the initial state shown in FIG.

[0098] In the example shown in FIG. 11, when the user wipes the screen 16 for cleaning, the broom 62 displayed on the screen 16 moves along a wiping path T1 along which the user has wiped the screen 16, which is indicated by a dashed line in FIG. 11. The control unit 20 then displays an image of the broom 62 moving along the wiping path T1 along which the user has wiped the screen 16, sweeping away an obstacle 61, which is a fallen leaf, from the wiping area. As the obstacle 61, which is a fallen leaf, is swept away from the screen 16 by the broom 62, the display content of the screen 16 returns to the initial state shown in FIG. 3. In this way, when the user has finished wiping the entire screen 16, the screen 16 returns to the initial state shown in FIG. 3.

[0099] When cleaning of the screen 16 is completed, the control unit 20 returns the mode from the cleaning execution mode to the cleaning management mode in response to the acceptance of an end operation by the user or a time limit. 12 to 14, the obstacle 63 may be a cherry blossom. Specifically, as shown in FIG. 12, a process is performed to display the obstacle 63 at a position on the screen 16 corresponding to the operation position by the user. In FIG. 12, the obstacle 63, which is, for example, a cherry blossom, is displayed at a position corresponding to the operation position by the user. Therefore, the obstacle 63 is displayed at the position where the user touches the screen 16 with his / her finger to operate the input unit 50. As a result, the visibility of the main screen MG, which is the display content of the display unit 15, decreases.

[0100] 13, the number of obstacles 63 on screen 16 increases stepwise as the cumulative value of at least one of the parameters, which is the time elapsed since the last screen cleaning, the number of user operations since the last screen cleaning, the operation time, and the number of people approaching multifunction device 11 since the last screen cleaning, increases. For the user, the greater the number of obstacles 63 on screen 16, the lower the visibility of the main screen MG, which is the display content. This lowering of the visibility of the display content on screen 16 prompts the user to clean screen 16.

[0101] When the user's visibility of the display content displayed on screen 16 decreases, the user cleans screen 16 at a certain timing, thereby returning the visibility of the display content on screen 16 to the initial state shown in FIG.

[0102] In the example shown in FIG. 14, when the user wipes the screen 16 for cleaning, the broom 62 displayed on the screen 16 moves along a wiping path T1 along which the user has wiped the screen 16, as indicated by a dashed line in FIG. 14. The control unit 20 then displays an image of the broom 62 moving along the wiping path T1 along which the user has wiped the screen 16, sweeping away obstacles 63, which are cherry blossoms, from the wiping area. As the obstacles 63, which are cherry blossoms, are swept away from the screen 16 by the broom 62, the display content of the screen 16 returns to the same initial state as in FIG. 3. In this way, when the user has finished wiping the entire screen 16, the screen 16 returns to the initial state shown in FIG. 3.

[0103] When cleaning of the screen 16 is completed, the control unit 20 returns the mode from the cleaning execution mode to the cleaning management mode upon receipt of an end operation by the user or upon receipt of a time limit. The control unit 20 may change the designs of the obstacles 61, 63 depending on the season to which the date belongs, based on the current date information managed by the internal clock. For example, if the current date information indicates that the current season is "autumn," the obstacle 61 will have a design of "fallen leaves" associated with autumn, as shown in Figs. 9 to 11. If the current date information indicates that the current season is "spring," the obstacle 61 will have a design of "cherry blossoms" associated with spring, as shown in Figs. 12 to 14.

[0104] According to the second embodiment, in addition to obtaining the same effects as those of the first embodiment (1-1), (1-2), and (1-4) to (1-13), the following effects are obtained. (2-1) The control unit 20 reduces the visibility of the display content at a position on the screen 16 corresponding to the position of the user's operation. According to this configuration, the visibility is reduced as the user operates more frequently at a position on the screen 16, which makes it easier to encourage the user to clean the screen 16 voluntarily.

[0105] (2-2) The decrease in visibility is caused by displaying the obstacles 61, 63. According to this configuration, the visibility is decreased by displaying the obstacles 61, 63 on the screen 16, which makes it easier to encourage the user to clean the screen 16 voluntarily.

[0106] Third embodiment Next, a third embodiment will be described with reference to Figures 15 to 17. Note that the basic configuration and electrical configuration of the multifunction device 11 are similar to those of the first embodiment, so the following will describe points that are particularly different from the first embodiment.

[0107] The control unit 20 reduces the visibility of the display content at a position on the screen 16 corresponding to the operation position by the user. In the first embodiment, the visibility of the entire display content of the screen 16 is reduced stepwise or continuously. In contrast, in the third embodiment, similar to the second embodiment, the visibility of the display content is partially reduced at a position on the main screen MG, which is the display content of the screen 16, corresponding to the operation position touched by the user. In the first embodiment, the visibility is reduced by changing the display density. In the third embodiment, similar to the first embodiment, the visibility is reduced by changing the display density.

[0108] That is, in the third embodiment, the visibility of the display content is partially reduced at a position on the screen 16 corresponding to the operation position by the user, and the process of reducing the visibility is performed by a process of reducing the display density.

[0109] Specifically, as shown in Fig. 15, a process is performed to display a low-density area 71 with a lowered display density at a position corresponding to the user's operation position on the screen 16. In Fig. 15, for example, a circular low-density area 71 is displayed at a position corresponding to the user's operation position. Therefore, the low-density area 71 is displayed at the position where the user touches the screen 16 with a finger or the like, and the visibility of the main screen MG, which is the display content, is reduced.

[0110] 16, the number of obstacles 61 on screen 16 increases stepwise as the cumulative value of at least one of the parameters, which is the time elapsed since the last screen cleaning, the number of user operations since the last screen cleaning, the operation time, and the number of people approaching multifunction device 11 since the last screen cleaning, increases. For the user, the greater the number of low-density areas 71 on screen 16, the lower the visibility of the main screen MG, which is the display content. This lowering of the visibility of the display content displayed on screen 16 prompts the user to clean screen 16.

[0111] When the visibility of the display content displayed on screen 16 decreases, the user cleans screen 16 at a certain timing. When cleaning screen 16, the user switches from cleaning management mode to cleaning execution mode. By wiping and cleaning screen 16, the user returns the visibility of the display content on screen 16 to the initial state shown in FIG.

[0112] In the example shown in Fig. 17, when the user wipes the screen 16 for cleaning, the wiping unit 72 displayed on the screen 16 displays the wiping unit 72 moving along the wiping path taken by the user to wipe the screen 16. Then, the control unit 20 returns the area wiped by the user on the screen 16, i.e., the area wiped by the wiping unit 72 following the wiping path taken by the user to wipe the screen 16, to the same display density as the initial state. In this way, when the user finishes wiping the entire screen 16, the screen 16 returns to the initial state shown in Fig. 3.

[0113] When cleaning of the screen 16 is completed, the control unit 20 returns the mode from the cleaning execution mode to the cleaning management mode in response to the acceptance of an end operation by the user or a time limit. According to the third embodiment, the effects (1-1) to (1-13) of the first embodiment and the effect (2-1) of the second embodiment can be obtained in the same way.

[0114] (Fourth embodiment) Next, a second embodiment will be described with reference to Figures 18 to 20. Note that the basic configuration and electrical configuration of the multifunction device 11 are similar to those of the first embodiment, so the following will describe points that are particularly different from the first embodiment.

[0115] The control unit 20 reduces the visibility of the display content at a position on the screen 16 corresponding to the operation position by the user. In the first embodiment, the visibility of the entire display content of the screen 16 is reduced stepwise or continuously. In contrast, in the fourth embodiment, similar to the second embodiment, the visibility of the display content is partially reduced at a position on the main screen MG, which is the display content of the screen 16, corresponding to the operation position touched by the user. Also, in the fourth embodiment, the reduction in visibility is performed by displaying an obstacle 73, similar to the second embodiment.

[0116] Specifically, as shown in Fig. 18, a process is performed to display an obstacle 73 at a position on the screen 16 corresponding to the position of the user's operation. In Fig. 18, an obstacle 73, for example a fingerprint, is displayed at a position corresponding to the position of the user's operation. Therefore, the obstacle 73 is displayed at the position where the user touched the screen 16 with a finger or the like, and the visibility of the main screen MG, which is the display content, decreases.

[0117] 19, the number of obstacles 73 on screen 16 increases stepwise as the cumulative value of at least one of the parameters, which is the time elapsed since the last screen cleaning, the number of user operations since the last screen cleaning, the operation time, and the number of people approaching multifunction device 11 since the last screen cleaning, increases. For the user, the greater the number of obstacles 73 on screen 16, the lower the visibility of the main screen MG, which is the display content. This decrease in visibility of the display content on screen 16 prompts the user to clean screen 16.

[0118] In this embodiment, an obstacle 73 is displayed at the position touched by the user, so that the user can visually recognize which positions on the screen 16 have been touched by multiple users, including other users. For example, it becomes possible to operate the input unit 50 while avoiding positions touched by other users.

[0119] Furthermore, the control unit 20 of this embodiment changes the display density of the obstacle 73 displayed at the touched position on the screen 16 to a lighter one as time passes from the time of display. Therefore, the user can estimate the length of time that has passed since another user touched the screen 16 from the display density of the obstacle 73. Therefore, the user can operate the input unit 50 of the screen 16 while avoiding obstacles 73 with high display density as much as possible. For example, the user can prevent contact infection with an infectious disease via the screen 16.

[0120] In the process of controlling the display density of the obstacles 73, the control unit 20 may individually manage the elapsed time from the display of the multiple obstacles 73 and individually change the display density of each obstacle 73 based on the elapsed time. Also, the control unit 20 may display all obstacles 73 at the same display density according to the elapsed time from the display of the newest obstacle 73 among the multiple obstacles 73.

[0121] When the visibility of the display content displayed on the screen 16 is reduced by the obstacle 73, the user cleans the screen 16 at a certain timing. When cleaning the screen 16, the user switches from the cleaning management mode to the cleaning execution mode. By wiping and cleaning the screen 16, the user returns the visibility of the display content on the screen 16 to the initial state shown in FIG.

[0122] In the example shown in FIG. 20, when the user wipes the screen 16 for cleaning, the wiping unit 74 displayed on the screen 16 moves along a wiping path T2 along which the user wiped the screen 16, indicated by a dashed line in FIG. 20. Then, the control unit 20 displays an image in which the wiping unit 74, which follows the wiping path T2 along which the user wiped the screen 16, wipes away and eliminates the obstacle 73, which is a fingerprint. When the obstacle 73, which is a fingerprint, is wiped off from the screen 16 by the wiping unit 74, the display content of the screen 16 returns to the same initial state as in FIG. 3. In this way, when the user finishes wiping the entire screen 16, the screen 16 returns to the initial state shown in FIG. 3.

[0123] When cleaning of the screen 16 is completed, the control unit 20 returns the mode from the cleaning execution mode to the cleaning management mode upon receipt of an end operation by the user or upon receipt of a time limit. According to the fourth embodiment, in addition to the same effects as those of the second embodiment, the following effects are obtained.

[0124] (4-1) The control unit 20 changes the display density of the obstacle 73 displayed at the touched position on the screen 16 to a lighter density as time passes from the time of display. This allows the user to operate the input unit 50 on the screen 16 while avoiding the obstacle 73 with a high display density as much as possible. For example, the user can prevent contact infection via the screen 16.

[0125] Fifth embodiment Next, a fifth embodiment will be described with reference to Figures 21 to 23. Note that the basic configuration and electrical configuration of the multifunction device 11 are similar to those of the first embodiment, so the following will describe points that are particularly different from the first embodiment.

[0126] The control unit 20 accumulates the value of at least one parameter since the previous screen cleaning, and reduces the visibility of the display content displayed on the screen 16 in accordance with the accumulated value of the parameter. The control unit 20 reduces the size of the input unit 50 displayed on the screen 16 in order to reduce the visibility of the display contents. In the fifth embodiment, the visibility is reduced by reducing the display area DA of the screen 16 in which the display screen is drawn. In the example shown in FIG. 21, the size of the main screen MG is reduced by reducing the display area DA. That is, the control unit 20 reduces the display size of the main screen MG to a small size, thereby reducing the display size of the input unit 50 on the main screen MG. This reduces the visibility of the display contents of the screen 16.

[0127] Specifically, as shown in FIG. 21, the display size of the display area DA on the screen 16 decreases stepwise or continuously as the cumulative value of at least one of the parameters, which is the elapsed time since the previous screen cleaning, the number of user operations since the previous screen cleaning, the operation time, and the number of people approaching the multifunction device 11 since the previous screen cleaning, increases. For example, each time the cumulative value of the parameter exceeds the first threshold value SV1, the display size of the display area DA decreases stepwise as shown in FIG. 21 and FIG. 22. For the user, the smaller the display size of the display area DA, the smaller the display size of the input unit 50, so the visibility of the input unit 50 decreases. This decrease in visibility of the display content of the screen 16 prompts the user to clean the screen 16.

[0128] When the visibility of the display content of screen 16 decreases due to the reduction in the display size of display area DA, the user cleans screen 16 at a certain timing. When cleaning screen 16, the user switches from cleaning management mode to cleaning execution mode. By wiping and cleaning screen 16, the user returns the visibility of the display content of screen 16 to the initial state shown in FIG.

[0129] In the example shown in Fig. 23, when the user wipes the screen 16 for cleaning, the wiping part 74 displayed on the screen 16 moves along a wiping path T2 by the user, which is shown by a dashed line in Fig. 23. Then, the control unit 20 gradually or continuously changes the display size of the display area DA to a larger size as the wiping area (e.g., the number of pixels) over which the user wipes the screen 16 increases.

[0130] In this example, the control unit 20 increases the display size of the display area DA stepwise each time the wiping area (e.g., the number of pixels) over which the user wipes the screen 16 exceeds the second threshold value SV2. Then, when the user wipes the entire screen 16, the display size of the display area DA of the screen 16 returns to the initial state shown in FIG. 3. In other words, the display size of the input unit 50 on the screen 16 returns to the same size as the initial state. In this way, when the user finishes wiping the entire screen 16, the screen 16 returns to the initial state shown in FIG. 3.

[0131] The control unit 20 returns the cleaning mode from the cleaning execution mode to the cleaning management mode when a termination operation is received from the user who has finished cleaning the screen 16, or when a time limit has elapsed since the display content of the screen 16 returned to the initial state.

[0132] According to the fifth embodiment, in addition to obtaining the effects (1-1), (1-2), (1-4), (1-5), and (1-7) to (1-13) in the first embodiment, the following effects are obtained.

[0133] (5-1) The decrease in visibility is caused by reducing the size of the input unit 50. According to this configuration, the decrease in the size of the input unit 50 on the screen 16 reduces the visibility, which makes it easier to encourage the user to clean the screen 16 voluntarily.

[0134] Sixth embodiment Next, a sixth embodiment will be described with reference to Figures 24 to 26. Note that the basic configuration and electrical configuration of the multifunction device 11 are similar to those of the first embodiment, so the following will describe points that are particularly different from the first embodiment.

[0135] The control unit 20 accumulates the value of at least one parameter since the previous screen cleaning, and reduces the visibility of the display content displayed on the screen in accordance with the accumulated value of the parameter. In order to reduce the visibility of the display contents, the control unit 20 reduces the size of the display area DA, which is an area in which the display contents (display screen) are displayed on the screen 16. In this sixth embodiment, the display size of a display screen such as the main screen MG displayed on the screen 16 is kept the same, and the display area DA in the screen 16 in which the display screen is displayed is reduced, thereby reducing the visibility of the display contents. In the example shown in FIG. 24, by reducing the display area DA, the area displayed in the main screen MG is reduced. In other words, the control unit 20 reduces the visibility of the main screen MG by reducing the display size of the display area DA in the main screen MG to a small size. This reduces the visibility of the display contents on the screen 16.

[0136] Specifically, as shown in FIG. 24, the display size of the display area DA on the screen 16 decreases stepwise or continuously as the cumulative value of at least one of the parameters, which is the time elapsed since the previous screen cleaning, the number of user operations since the previous screen cleaning, the operation time, and the number of people approaching the multifunction device 11 since the previous screen cleaning, increases. For example, each time the cumulative value of the parameter exceeds the first threshold value SV1, the display size of the display area DA decreases stepwise as shown in FIG. 24 and FIG. 25. For the user, the smaller the display size of the display area DA, the smaller the display size of the display area DA in the main screen MG, and therefore the lower the visibility of the main screen MG. This decrease in visibility of the display content of the screen 16 prompts the user to clean the screen 16.

[0137] When the visibility of the display content of screen 16 decreases due to the reduction in the display size of display area DA, the user cleans screen 16 at a certain timing. When cleaning screen 16, the user switches from cleaning management mode to cleaning execution mode. By wiping and cleaning screen 16, the user returns the visibility of the display content of screen 16 to the initial state shown in FIG.

[0138] In the example shown in Fig. 26, when the user wipes the screen 16 for cleaning, the wiping part 74 displayed on the screen 16 moves along a wiping path T2 by the user, which is indicated by a dashed line in Fig. 26. Then, the control unit 20 gradually or continuously changes the display size of the display area DA to a larger size as the wiping area (e.g., the number of pixels) over which the user wipes the screen 16 increases.

[0139] In this example, the control unit 20 increases the display size of the display area DA stepwise each time the wiping area (e.g., the number of pixels) over which the user wipes the screen 16 exceeds the second threshold value SV2. Then, when the user wipes the entire screen 16, the display size of the display area DA of the screen 16 returns to the initial state shown in FIG. 3. In other words, the display size of the input unit 50 on the screen 16 returns to the same size as the initial state. In this way, when the user finishes wiping the entire screen 16, the screen 16 returns to the initial state shown in FIG. 3.

[0140] The control unit 20 returns the cleaning mode from the cleaning execution mode to the cleaning management mode when a termination operation is received from the user who has finished cleaning the screen 16, or when a time limit has elapsed since the display content of the screen 16 returned to the initial state.

[0141] According to the sixth embodiment, in addition to obtaining the effects (1-1), (1-2), (1-4), (1-5), and (1-7) to (1-13) in the first embodiment, the following effects are obtained.

[0142] (6-1) The decrease in visibility is caused by reducing the size of the display area DA, which is the area in which the display content is displayed on the screen 16. According to this configuration, the decrease in the size of the display area DA on the screen 16 reduces the visibility, which makes it easier to encourage the user to clean the screen 16 voluntarily.

[0143] The above embodiment can be modified to the following modified examples. Further modified examples can be appropriately combined with the above embodiment and the following modified examples, or further modified examples can be appropriately combined with each other.

[0144] In the first embodiment, in order to reduce the visibility of the display content on the screen 16, the obstacles 61, 63, 73 in the second and fourth embodiments may be further displayed. In the second embodiment, the control unit 20 may gradually or continuously decrease the display density of the obstacles 61, 63 in accordance with the elapsed time from the time the obstacles 61, 63 are displayed, as in the fourth embodiment.

[0145] In the second embodiment, instead of an image of the obstacles 61, 63 being swept away when the user cleans the screen 16, an image of the obstacles 61, 63 being wiped away may be displayed as in the fourth embodiment.

[0146] In the first and third embodiments, the visibility of the display contents may be reduced by increasing the display density. In the first embodiment, the visibility of the display screen may be reduced by increasing the display density of the main screen MG, which is the display screen. In the third embodiment, a high-density region may be adopted instead of the low-density region 71.

[0147] In the fifth and sixth embodiments, the visibility of the display content may be reduced by reducing the display density of the display content. In each embodiment, the display device may be configured to have a cleaning management mode and not have a cleaning execution mode.

[0148] The multifunction device 11 as an example of a display device may have a reading section of either a flatbed type or a feed type. The display device is not limited to the multifunction device 11, and may be a printer without a scanning mechanism or copy function. In this case, the printer may be an inkjet printer or a dot impact printer. The display device may also be a textile printing machine. The multifunction device 11 and the printer may be any of a serial printer, a line printer, and a page printer.

[0149] The display device may be a scanner having a display unit. The display device may be an electronic device other than the multifunction device 11, printer, or scanner. In other words, the display device may be any electronic device having a display unit. The electronic device may be a home appliance having a display unit. In addition, if the number of people approaching the display device is used as a parameter, it is preferable that the electronic device be one that is shared by multiple people.

[0150] The technical concepts and effects obtained from the above-described embodiment and modified examples will be described below. (A) A display device having a display unit having a screen and a control unit that changes the display content of the screen, the display unit having an input unit that can input a position on the screen as a contact position by touching the screen, and the control unit that controls the display unit, and when at least one of factors that represent the degree of contamination of the screen since the last time the screen was cleaned is used as a parameter, the control unit accumulates the value of at least one of the parameters since the last time the screen was cleaned and reduces the visibility of the display content displayed on the screen in accordance with the accumulated value of the parameter.

[0151] According to this configuration, the visibility of the display content is reduced based on the cumulative value of at least one parameter accumulated since the previous screen cleaning, so that the reduced visibility can encourage the user to voluntarily clean the screen, thereby reducing the frequency with which the screen is left uncleaned.

[0152] (B) In the above display device, at least one of the parameters may include at least one of the following: the time elapsed since the last time the screen was cleaned, the number of operations performed by touching the screen since the last time the screen was cleaned, the operation time, and the number of people who have approached the display device since the last time the screen was cleaned.

[0153] According to this configuration, at least one of the following parameters is used: the time elapsed since the last screen cleaning, the number of operations, the operation time, or the number of people approaching the display device, so that the user can be encouraged to voluntarily clean the screen at an appropriate cleaning timing.

[0154] (C) In the above display device, the control unit may reduce the visibility of the display content at a position on the screen corresponding to a position of an operation by a user. According to this configuration, the degree of visibility decreases as the user operates a position on the screen more frequently, which makes it easier to encourage the user to clean the screen voluntarily.

[0155] (D) In ​​the display device, the decrease in visibility may be achieved by changing the display density. With this configuration, the visibility decreases as the display density changes on the screen, which makes it easier to encourage users to clean the screen voluntarily.

[0156] (E) In the display device, the decrease in the degree of visibility may be caused by displaying an obstacle. According to this configuration, the degree of visibility is decreased by displaying an obstacle on the screen, which makes it easier to encourage the user to clean the screen voluntarily.

[0157] (F) In the display device, the decrease in visibility may be achieved by reducing the size of the input unit. According to this configuration, the size of the input section on the screen is reduced, thereby reducing the degree of visibility, which makes it easier to encourage the user to clean the screen voluntarily.

[0158] (G) In the above display device, the decrease in visibility may be achieved by reducing the size of a display area on the screen where the display content is displayed. According to this configuration, the size of the operation unit on the screen is reduced, thereby reducing the degree of visibility, which makes it easier to encourage the user to clean the screen voluntarily.

[0159] (H) In the display device described above, the control unit may return the visibility to an initial state when cleaning of the screen is performed. According to this configuration, when the screen is cleaned, the visibility returns to the initial state, which makes it easier to encourage cleaning.

[0160] (I) In the above display device, the control unit may increase the visibility stepwise or continuously as cleaning of the screen progresses. According to this configuration, as the cleaning of the screen progresses, the degree of visibility increases, making it easy to recognize the degree of cleaning progress.

[0161] (J) In the above display device, the control unit may increase the visibility of an area of ​​the screen that has been cleaned. This configuration allows the user to recognize the progress of cleaning of the screen. For example, it is less likely that cleaning will be left undone.

[0162] (K) In the display device, the control unit may have a cleaning management mode that prompts the user to clean the screen, executes a process of lowering the visibility of the display content in accordance with the accumulated value of the parameter when the cleaning management mode is on, and is configured to be able to switch the cleaning management mode on and off. With this configuration, the user can select the prompt to clean the screen when desired.

[0163] (L) In the above display device, the control unit may reduce the visibility of the display content when the cumulative value of the parameter exceeds a threshold value. According to this configuration, the visibility of the display content can be gradually decreased according to the cumulative value of the parameter, thereby reducing the processing load on the control unit, for example.

[0164] (M) The display device may further include a threshold change operation unit that is operated by a user to change the threshold. According to this configuration, the user can change the threshold by operating the threshold change operation unit, and can adjust the speed at which the visibility is reduced, thereby encouraging the user to clean the screen at a more appropriate time.

[0165] (N) In the display device, the control unit may obtain the overall accumulated value of a plurality of parameters using a conversion formula between the plurality of parameters, and determine whether or not the accumulated value exceeds the threshold value.

[0166] According to this configuration, since the overall cumulative value of multiple parameters is appropriately obtained using the converted value, the degree of contamination of the screen can be appropriately evaluated based on multiple factors, and the user can be prompted to clean the screen at a more appropriate time.

[0167] (O) In the above-mentioned display device, a detection unit may be provided that detects at least one of the temperature, humidity, amount of dust, amount of oil in the surrounding environment, and the body temperature of the operator, and the accumulated value of the parameters may be corrected by multiplying the accumulated value of the parameters by a coefficient corresponding to the detection amount obtained by the detection unit, or the threshold value may be changed based on the detection value obtained by the detection unit.

[0168] According to this configuration, the degree of contamination of the screen is evaluated based on a cumulative value that takes into account at least one of the temperature, humidity, amount of dust, amount of oil in the surrounding environment, and the body temperature of the operator, thereby making it possible to prompt the operator to clean the screen at a more appropriate time.

[0169] (P) A display control method for a display device having a display unit with a screen, the display device comprising: a display unit having an input unit for inputting a position on the screen as a contact position by touching the screen; and a control unit for controlling the operation of the display unit, the control unit having a cleaning management mode as an operation mode of the display unit for prompting cleaning of the screen, the control unit accumulating values ​​of at least one of the following parameters at least in the cleaning management mode: the elapsed time from the last cleaning, the number of operations, the operation time, and the number of people approaching the multifunction device, and decreasing the visibility of the display content of the display unit according to the accumulated value of the parameter; and changing the visibility of the display content of the display unit to a higher level according to the contact area detected by cleaning the screen. According to this method, the frequency with which the screen is left uncleaned can be reduced, similar to the display device.

[0170] (Q) A display control program executed by a computer included in a display device having a display unit with a screen, the display device comprising: a display unit having an input unit for inputting a position on the screen as a contact position by touching the screen; and a computer for controlling the operation of the display unit, the computer having a cleaning management mode as an operation mode of the display unit for prompting cleaning of the screen, and the computer is made to execute the steps of: accumulating values ​​of at least one of the following parameters: the time elapsed since the last cleaning, the number of operations, the operation time, and the number of people approaching the multifunction device, in at least the cleaning management mode; lowering the visibility of the display content of the display unit according to the accumulated value of the parameter; and increasing the visibility of the display content of the display unit according to the contact area detected by cleaning the screen. According to this program, the frequency with which the screen is left uncleaned can be reduced, similar to the display device. [Explanation of symbols]

[0171] 11...Multifunction device as an example of a display device, 12...Main body, 13...Reading unit, 13A...Document table, 14...Automatic feed unit, 14A...Document tray, 14B...Edge guide, 15...Display unit, 16...Screen, 17...Printing unit, 18...Cassette, 19...Discharge unit, 19A...Discharge tray, 20...Control unit, 21...Operation unit, 22...Transport unit, 23...Recording head, 24...Contact detection unit, 25...First sensor, 26...Second sensor as an example of a detection unit, 30...Computer, 31...First timer unit, 32...Second timer unit, 33...First counter, 34...Second counter, 35...Display control unit, 36...Memory unit, 41... Operation detection unit, 42...touch position detection unit, 50...input unit, 51...print button, 52...scan button, 53...copy button, 54...operation button, 55...operation button, 56...wiping unit, 61...obstacle, 62...broom, 63...obstacle, 71...low concentration area, 72...wiping unit, 73...obstacle, 74...wiping unit, MG...main screen, PR...program, SV1...first threshold, SV2...second threshold, ID1...first image data, ID2...second image data, F...accumulated value, BG...background, MS...message, T1...wiping path, T2...wiping path, DA...display area, X...depth direction, Y...width direction, Z...vertical direction.

Claims

1. A display device having a display unit with a screen and a control unit that changes the display content of the screen. There was, an input unit capable of inputting a position on the screen as a contact position by touching the screen; The display unit having The control unit controls the display unit, At least one of the factors representing the degree of contamination of the screen since the last time the screen was cleaned is set as a parameter. If we use The control unit accumulates a value of at least one of the parameters since the last time the screen was cleaned. The visibility of the display content displayed on the screen is reduced according to the cumulative value of the parameter. height, The display device according to claim 1, wherein the degree of visibility is reduced by reducing the size of the input unit.

2. A display device having a display unit with a screen and a control unit that changes the display content of the screen. There was, an input unit capable of inputting a position on the screen as a contact position by touching the screen; The display unit having The control unit controls the display unit, At least one of the factors representing the degree of contamination of the screen since the last time the screen was cleaned is set as a parameter. If we use The control unit accumulates a value of at least one of the parameters since the last time the screen was cleaned. The visibility of the display content displayed on the screen is reduced according to the cumulative value of the parameter. height, The decrease in the visibility is caused by a decrease in the size of a display area, which is an area where the display content is displayed on the screen. A display device characterized by reducing noise.

3. At least one of the parameters may be the time since the last screen cleaning, the last screen cleaning time, Displays the number of times the screen has been touched since cleaning, the operation time, and the time since the last screen cleaning The method according to claim 1 or 2, characterized in that the method includes at least one of the following: The display device described.

4. The control unit returns the visibility to an initial state when the screen is cleaned. The display device according to any one of claims 1 to 3.

5. The control unit changes the visibility in a stepwise or continuous manner as the cleaning of the screen progresses.

5. The display device according to claim 4, wherein the height is increased.

6. The control unit is configured to increase the visibility of an area of ​​the screen that has been cleaned. The display device according to any one of claims 1 to 5.

7. The control unit has a cleaning management mode that prompts cleaning of the screen, and When the cleaning management mode is on, the process of decreasing the parameter in accordance with the accumulated value of the parameter is performed. Run to The cleaning management mode is configured to be switchable between on and off. The display device according to any one of claims 1 to 6.

8. When the cumulative value of the parameter exceeds a threshold, the control unit 8. The display device according to claim 1, wherein the display device reduces

9. The present invention is characterized in that the threshold value is changed by a user through a threshold value change operation unit. The display device according to claim 8 .

10. The control unit performs a comprehensive calculation of the plurality of parameters using a conversion formula between the plurality of parameters. and acquiring the cumulative value and determining whether the cumulative value exceeds the threshold value. The display device according to claim 8 or 9.

11. At least one of the following factors must be considered: temperature, humidity, dust, oil content of the surrounding environment, and the operator's body temperature. a detection unit for detecting the The cumulative value of the parameter is multiplied by a coefficient according to the amount of detection obtained by the detection unit. or correcting the cumulative value by adjusting the threshold value based on the detection value obtained by the detection unit. The display device according to any one of claims 8 to 10, wherein the value is changed. 。

12. A display control method for a display device including a display unit having a screen, comprising: The display device includes: An input for inputting a position on the screen as a contact position by touching the screen. The display unit having a display part; A control unit for controlling an operation of the display unit, and the control unit having a cleaning management mode that prompts cleaning of the surface, The control unit, at least in the cleaning management mode, The parameters are at least one of the number of operations, the operation time, and the number of people approaching the multifunction device. and accumulating the value of the parameter, and displaying the accumulated value of the parameter on the display unit. reducing the size of the input section to be The size of the input unit is increased according to the contact area detected by cleaning the screen. To do, 13. A display control method for a display device comprising:

13. A display control system executed by a computer equipped with a display device having a display unit with a screen A program, The display device includes: An input for inputting a position on the screen as a contact position by touching the screen. The display unit having a display part; The computer controls the operation of the display unit, and and the computer having a cleaning management mode that prompts cleaning of the screen, The computer includes: At least in the cleaning management mode, the time elapsed since the previous cleaning, the number of operations, At least one of the parameters, such as the operation time, the number of people approaching the multifunction device, The input part displayed on the display unit is determined according to the accumulated value of the parameter. reducing the size; The size of the input unit is increased according to the contact area detected by cleaning the screen. Steps to A display control program that causes a display to be controlled by executing the above steps.

Images