JP6493080B2 - Operation panel and image forming apparatus having the same - Google Patents

Description

  The present invention relates to an image forming apparatus, and more particularly to a technique for causing a touch panel incorporated in an operation panel of the apparatus to respond to vibration with respect to a detected contact.

  Touch panels are now becoming established as input devices indispensable for the operation of electrical equipment. In fact, any bank's automatic teller machine (ATM) and any station's automatic ticket vending machines are equipped with touch panels as standard. The touch panel is a standard input device for both smartphones and tablet terminals that have exploded in popularity. In recent years, there have been many types of home appliances in which a touch panel is incorporated in an operation panel.

  The reason why touch panels have become widespread in this way is largely due to the good operational feeling they give users. If the touch panel is used, the user can directly touch and operate graphic user interface (GUI) parts (hereinafter referred to as “gadgets”) such as icons and virtual buttons displayed on the operation screen. That is, the user does not need to handle a keyboard or a mouse. Therefore, it is difficult for a user who is unfamiliar with these treatments to be confused by the operation of the gadget. Because of such easy-to-understand operation, the operation feeling given to the user by the touch panel is good.

  As a device for further improving the operational feeling, for example, a technique is known in which a touch panel responds to detected contact with light or sound. Specifically, in response to the touch panel detecting contact with a user's finger or the like, the display changes the form such as the color, shape, and brightness of the gadget, or the speaker generates an electronic sound. From such a visual or auditory response, the user feels “responsiveness” (also referred to as “click feeling” or “feedback”) to the touch on the touch panel. That is, it is possible to convince the user that the operation by the contact has been accepted by the apparatus.

  In recent years, touch panels equipped with a force feedback (FFB) function have been developed as a technique for further enhancing the effect of this feedback (see, for example, Patent Documents 1-5). The “FFB function” refers to a function that vibrates the touch panel (particularly the surface that the user can touch) in response to detection of contact by the touch panel. With this vibration (hereinafter referred to as “response vibration”), it is possible to give the user an illusion of a response when touching a virtual button or the like, as if a response when pressing a mechanical button. Since the response vibration is a tactile response, it can be sufficiently sensed by a user such as a child or an elderly person who is relatively poor at sensing gadget morphological changes or electronic sounds.

JP 2012-176640 A JP 2012-038289 A JP 2011-113461 A JP 2008-217237 A JP 2006-040005 A

  The use of touch panels extends to in-vehicle electronic devices such as car audio and car navigation systems, image forming apparatuses such as printers and copiers, and machine tools such as industrial robots. When operating these devices, users usually cannot keep looking at the touch panel alone. Also, since the operating sound or environmental noise of these devices is generally loud, electronic sounds are difficult for the user to hear. Therefore, in order to improve the operational feeling given to the user by the touch panels mounted on these devices, it is desirable to mount the FFB function on these touch panels.

However, in-vehicle electronic devices, image forming apparatuses, machine tools, and the like are accompanied by large vibrations in their own operations, or in the operations of systems such as automobiles in which they are incorporated. Therefore, there is a need for a technology that allows the user to reliably detect the response vibration of the touch panel by the FFB function in a situation where this vibration (hereinafter referred to as “background vibration”) exists.
As a conventional technique, for example, a vehicle touch panel disclosed in Patent Document 1 is known. This technology causes the touch panel to detect the vibration of the vehicle body as the vehicle travels, and amplifies the response vibration as the amplitude of the vibration increases.

  However, in this technique, the detection operation of the background vibration is indispensable when generating the response vibration. Therefore, it is unavoidable that a delay occurs between the detection of contact by the touch panel and the output of the response vibration, and it is difficult to suppress variations in the delay. Regardless of this delay and its variation, how can the response vibration be amplified in accordance with the background vibration in order for the user to reliably detect the response vibration? It is by no means obvious to those skilled in the art.

  An object of the present invention is to solve the above-described problem, and in particular, an operation panel capable of causing a user to reliably detect a response vibration in response to a detected contact regardless of a background vibration associated with an operation of a mounting destination device. It is to provide.

  An operation panel according to one aspect of the present invention is an operation panel that is mounted on a device that vibrates in operation, displays an operation screen of the device, and accepts a user operation on the operation screen. Including a touch panel for detecting contact with the display area by an external object, a vibration generator for applying vibration to the display area, and detecting vibrations associated with the operation during the operation of the device on which the device is mounted, The vibration detection unit that obtains the spectrum of this vibration as the background vibration spectrum, and whether the vibration detection unit detects background vibration in response to the touch detected by the touch panel, detects vibration in the vibration generation unit. If the part does not detect the background vibration, the vibration showing the first spectrum; if the vibration detection part detects the background vibration, the vibration showing the second spectrum; And a response control unit which causes addition to the display area in response to respectively contact. The response control unit sets a vibration level difference or ratio between the first spectrum and the second spectrum for each natural frequency of the display region based on the background vibration spectrum detected by the vibration detection unit.

The response control unit amplifies at least one of the frequency components included in the spectrum of the background vibration, adds the vibration level to the vibration level of the same frequency component included in the first spectrum, and adds the obtained sum to the second You may set to the vibration level of the same frequency component which a spectrum contains.
The response control unit may set a spectrum obtained by adding a frequency component that does not include the spectrum of the background vibration to the first spectrum as the second spectrum.

The operation screen may include a setting screen related to vibration to be generated by the vibration generation unit. In this case, the response control unit may correct the second spectrum in accordance with a user operation on the setting screen. The correction of the second spectrum by the response control unit may include an increase or decrease in the vibration level, or setting an upper limit or a lower limit for the vibration level.
The operation panel may further include a storage unit that stores a minimum value of the duration of the background vibration for each operation mode of the installation destination device. In this case, the response control unit identifies the operation mode of the mounting destination device at the time of detection according to the touch panel detecting contact, and the duration of the background vibration detected by the vibration detection unit at the time of detection is the operation When the value is below the minimum value in the mode, the vibration generating unit may be caused to add vibration to the display area as a response to the contact.

  An image forming apparatus according to one aspect of the present invention includes an image forming unit that forms an image on a sheet, and the operation panel that displays an operation screen for the image forming unit and receives a user operation on the operation screen. ing.

  In the operation panel according to the present invention, the response control unit calculates the difference or ratio of response vibration levels between the first spectrum and the second spectrum based on the background vibration spectrum, and the natural frequency in the display area of the operation screen. Set for each. This ensures that the user can detect the difference in vibration before and after superimposing the response vibration on the background vibration, regardless of the delay between touch detection by touch panel and response vibration output. The second spectrum can be set so that it is possible. In this way, this operation panel can make the user surely sense the response vibration to the detected contact regardless of the background vibration accompanying the operation of the device at the mounting destination.

(A) is a perspective view which shows the external appearance of the image forming apparatus by embodiment of this invention, (b) is a disassembled perspective view of the touchscreen mounted in this image forming apparatus. 2A is a cross-sectional view of the automatic document feeder and the scanner shown in FIG. 1A taken along line II-II, and FIG. 1B is an internal view of the printer shown in FIG. It is a front view which shows a structure typically. FIG. 2 is a block diagram illustrating a configuration of an electronic control system of the image forming apparatus illustrated in FIG. It is a functional block diagram of the operation panel shown in FIG. (A) is a list of nodal curves of natural vibration modes (m = 1-3, n = 1-3) of the touch panel shown in FIG. 1 (b), and (b) is a natural vibration mode (m , N) = (1,1), (1,2), (2,1) is a schematic diagram showing the vibration form, and (c) shows the vibration waveform in each natural vibration mode shown in (b). It is a graph, (d) is a graph of the vibration waveform actually generated on the touch panel. (A) is a functional block diagram of the vibration detection unit shown in FIG. 4, (b) is a graph showing a time waveform of background vibration indicated by the output of the acceleration sensor, and (c) is based on the time waveform. It is a graph which shows the frequency distribution of the amplitude of the background vibration which the vibration detection part analyzed, ie, a spectrum. It is a graph which shows the 1st method of transforming the spectrum of response vibration based on the spectrum of background vibration. It is a graph which shows the 2nd method of transforming the spectrum of response vibration based on the spectrum of background vibration. It is a flowchart of the FFB process by a touch panel. FIG. 10 is a flowchart of a subroutine for transforming the response vibration spectrum in the first method shown in FIG. 7 in step S106 shown in FIG. 9; FIG. 10 is a flowchart of a subroutine for transforming a response vibration spectrum in the second method shown in FIG. 8 in step S106 shown in FIG. 9; FIG. 11 is a flowchart of a subroutine in which processing for increasing / decreasing the amplitude of response vibration is added to the processing shown in FIG. 10 in accordance with user preference. 11 is a flowchart of a subroutine in which a process for limiting the vibration level of the second spectrum is added to the process shown in FIG. 10. (A) is a graph showing the time waveform of background vibration, and (b) is a correspondence table between the operation mode of the image forming apparatus shown in FIG. 1 and the detection lower limit of the duration of background vibration. It is a flowchart at the time of adding the process which excludes the vibration whose duration is shorter than a detection lower limit from background vibration with respect to the FFB process shown in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Appearance of image forming apparatus]
FIG. 1A is a perspective view showing an appearance of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus 100 is a multi-function peripheral (MFP) that has a function of a scanner, a color copier, and a color laser printer. Referring to FIG. 1A, an automatic document feeder (ADF) 110 is mounted on the top surface of the MFP 100 so as to be openable and closable. A scanner 120 is built in the upper part of the casing located directly under the ADF 110, a printer 130 is built in the lower part, and a plurality of stages of paper feed cassettes 140 are attached to the bottom of the scanner 130 so that they can be pulled out. A gap GAP is opened between the scanner 120 and the printer 130, and a paper discharge tray 150 is disposed therein. A paper discharge port 131 is installed in the back of the gap GAP, and a sheet is discharged from the paper discharge tray 150 to the paper discharge port 131. An operation panel 160 is attached to the front portion of the housing located beside the gap GAP. A touch panel 170 is embedded in the front surface of the operation panel 160, and various mechanical push buttons 161 are arranged around the touch panel 170. The touch panel 170 displays a GUI screen such as an operation screen and various information input screens, and accepts a user input operation through gadgets such as icons, virtual buttons, menus, and toolbars included in the GUI screen.

[Touch panel structure]
FIG. 1B is an exploded perspective view of the touch panel 170 shown in FIG. Referring to FIG. 1B, the touch panel 170 includes a structure in which a liquid crystal display (LCD) 171, a touch pad 172, a cover 173, and a piezoelectric actuator 174 are stacked.

The LCD 171 modulates the uniform light of the backlight in units of pixels in accordance with a voltage applied from the control circuit board 175 through the flexible printed circuit board (FPC) 176. As a result, the brightness of the screen changes in units of pixels, and an image is displayed on the screen.
The touch pad 172 is stacked on the screen of the LCD 171 and includes, for example, a resistance film type structure. Specifically, the upper surface of a substrate made of transparent glass or the like is covered with a transparent conductive film made of indium tin oxide (ITO) or the like, and another transparent conductive film is spread on the spacer with a spacer in between. Yes. The two conductive films are connected to an external electronic circuit through the cable 177, and are alternately supplied with current from the circuit. At this time, when the user's finger touches the touch panel 170, the upper conductive film is recessed and short-circuited with the lower conductive film at the contact portion, so that the potential of the conductive film that is not supplied with current changes. . The contact of the finger is detected from this change in potential, and the coordinates of the contact point are calculated from the amount of change.

The cover 173 is a transparent film made of a resin such as polyethylene terephthalate (PET), and covers the upper surface of the touch pad 172 to protect it from external dust and moisture.
The piezoelectric actuator 174 is a band-shaped thin film member made of a piezoelectric material such as lead zirconate titanate (PZT). For example, a plurality of piezoelectric actuators 174 are formed along the circumference of the touch pad 172 (see FIG. 1B). (2 sheets) are bonded. The piezoelectric actuator 174 deforms (for example, extends in the longitudinal direction) when a voltage is applied from the outside, and returns to its original shape (for example, the original length) when the voltage is removed. Therefore, if the voltage application is repeated periodically, the piezoelectric actuator 174 vibrates at a frequency equal to the frequency.

[ADF structure]
2A is a cross-sectional view of the ADF 110 shown in FIG. 1A along the line II-II. Referring to FIG. 2A, the ADF 110 takes in the document DC0 from the paper feed tray 111 one by one into the paper feed opening 113 by the paper feed roller 11A and feeds it by the transport roller group 11B-11G. The paper is sent from the opening 113 to the paper discharge outlet 115 along the conveyance path, and is discharged from the paper discharge outlet 115 by the paper discharge roller 11H. The document DC2 discharged from the discharge port 115 is stored in the discharge tray 112. While the document passes through this conveyance path, the surface of the ADF 110 is scanned on the bottom surface by the irradiation light from the scanner 120, and the inside of the ADF 110 is scanned on the back surface by the irradiation light from the back surface scanner 116.

[Scanner structure]
2 (a) also includes a cross-sectional view of the scanner 120 shown in FIG. 1 (a) along line II-II. Referring to FIG. 2A, the contact glass 121 that closes the slit opened on the upper surface of the scanner 120 faces a part of the document conveyance path exposed on the bottom surface of the ADF 110. The scanner 120 irradiates light on the surface of the original passing through a part of the transport path through the contact glass 121 and detects the reflected light. On the upper surface of the scanner 120, the platen glass 122 also closes an opening other than the slit that the contact glass 121 closes. The scanner 120 irradiates the surface of the document placed thereon through the platen glass 122 and detects the reflected light.

  Inside the scanner 120, a slider 123 is installed so as to be able to reciprocate between the position immediately below the contact glass 121 and the end of the platen glass 122. The slider 123 irradiates the surface of the document with the light of the line light source 128 through the contact glass 121 or the platen glass 122 from its upper surface. The slider 123 further reflects the light reflected from the surface of the original and incident from the upper surface toward the pair of mirrors 124 and the lens 125 by the mirror 129. The optical elements 124 and 125 focus the reflected light, and the line sensor 126 detects the light amount. Since the amount of light changes according to the color of the surface of the document (more precisely, the light reflectance), the electrical signal output from the line sensor 126 in response to the detection of the amount of light is an image displayed on the surface of the document. Represent. Similarly, the electrical signal output from the back scanner 116 represents an image displayed on the back of the document. These electrical signals are converted into image data by the image processing unit 127 and output to the printer 130 or an external electronic device.

[Printer structure]
FIG. 2B is a front view schematically showing the structure of the printer 130. In FIG. 2B, the elements of the printer 130 are depicted as if they were seen through the front surface of the housing. Referring to FIG. 2B, the printer 130 is an electrophotographic color printer, that is, a color leather printer, and includes a feeding unit 10, an image forming unit 20, a fixing unit 30, a paper discharge unit 40, and an acceleration sensor 90. including. The feeding unit 10 to the paper discharge unit 40 cooperate to function as an image forming unit of the MFP 100, and form an image on a sheet based on the image data. The acceleration sensor 90 detects vibration (hereinafter referred to as “background vibration”) accompanying the operation of the image forming unit 10-40.

  The feeding unit 10 feeds sheets SHT one by one from the sheet feeding cassette 11 or the manual feed tray 16 to the image forming unit 20 by using the transport roller groups 12P, 12F, 12R, 13, 14, and 15. The material of the sheet SHT is, for example, paper or resin, the paper type is, for example, plain paper, high-quality paper, color paper, or coated paper, and the size is, for example, A3, A4, A5, or B4.

  The image forming unit 20 forms a toner image on the sheet SH2 sent from the feeding unit 10. Specifically, each of the four image forming units 21Y, 21M, 21C, and 21K first uses the laser light from the exposure unit 26 to base the surface of the photosensitive drums 25Y, 25M, 25C, and 25K on the basis of image data. Then, an electrostatic latent image is formed on the surface. Each image forming unit 21Y,... Then develops the electrostatic latent image with yellow (Y), magenta (M), cyan (C), and black (K) toners. The obtained four-color toner images are formed on the surface of the intermediate transfer belt 23 in order from the surface of the photosensitive drums 25Y,... By the electric field between the primary transfer rollers 22Y, 22M, 22C, 22K and the photosensitive drums 25Y,. Transferred to the same position above. Thus, one color toner image is formed at that position. This color toner image is further transferred to the surface of the sheet SH2 that has passed through the nip between the intermediate transfer belt 23 and the secondary transfer roller 24 through the nip between the two toner images 23 and 24. Thereafter, when a separation voltage is applied to the sheet SH2, the sheet SH2 is peeled off from the secondary transfer roller 24 and sent to the fixing unit 30.

  The fixing unit 30 heat-fixes the toner image on the sheet SH2 sent out from the image forming unit 20. Specifically, when the sheet SH2 is passed through the nip between the fixing roller 31 and the pressure roller 32, the fixing roller 31 applies heat of a built-in heater to the surface of the sheet SH2, and the pressure roller No. 32 applies pressure to the heated portion of the sheet SH <b> 2 and presses it against the fixing roller 31. The toner image is fixed on the surface of the sheet SH <b> 2 by the heat from the fixing roller 31 and the pressure from the pressure roller 32. Thereafter, the fixing unit 30 sends the sheet SH2 from the top along the guide plate 41 to the paper discharge port 42.

The paper discharge unit 40 discharges the sheet SH2 sent from the fixing unit 30 from the paper discharge port 42 by the paper discharge roller 43 and stores it in the paper discharge tray 46.
Acceleration sensor 90 is installed in a portion of MFP 100 that hardly vibrates, such as a chassis (not shown in FIG. 2). The acceleration sensor 90 is, for example, a capacitance type, and includes a detection element and a signal processing circuit. The detection element is a micro electro mechanical system (MEMS), and includes a minute weight supported by a minute spring, and a pair of comb electrodes fixed to each of the surface of the weight and the element body and meshing with each other. When the detection element receives vibration from the outside, acceleration is generated in the weight, the weight is displaced, and the distance between the comb electrode pairs is expanded and contracted. The signal processing circuit outputs a voltage signal proportional to the acceleration received by the weight by amplifying the change in electrostatic capacitance between the comb-tooth electrode pair accompanying the expansion and contraction of the interval.

[Electronic control system of image forming apparatus]
FIG. 3 is a block diagram showing the configuration of the electronic control system of MFP 100. Referring to FIG. 3, in this system, an image forming unit, that is, a printer 130, an operation unit 50, an image input unit 60, a main control unit 70, and an acceleration sensor 90 are connected to each other through a bus 80 so as to communicate with each other.

-Operation part-
The operation unit 50 is the entire input device (UI) mounted on the MFP 100, such as the operation panel 160. The operation unit 50 receives and interprets user operations and notifies the main control unit 70. In particular, operation panel 160 includes vibration generation unit 51, control unit 53, and display unit 54 in addition to touch panel 170. The vibration generation unit 51 is a combination of the piezoelectric actuator 174 shown in FIG. 1B and its drive circuit, and drives the piezoelectric actuator 174 to vibrate the touch panel 170, particularly the display area of the operation screen included therein. Add The control unit 53 is configured by an integrated circuit such as a microprocessor (MPU / CPU), an ASIC, or an FPGA. The control unit 53 receives and interprets the user's input operation through the touch pad 172 shown in FIG. 1B or the push button 161 shown in FIG. 1A, and information on the input operation based on the interpretation. (Hereinafter referred to as “operation information”) is generated and transmitted to the main control unit 70. The display unit 54 is a combination of the LCD 171, the control circuit board 175, and the FPC 176 shown in FIG. 1B and a signal processing circuit (DSP) that provides image data to them in an appropriate manner. The display unit 54 reproduces the GUI screen in the display area of the touch panel 170 by processing the image data of the GUI screen such as an operation screen in accordance with an instruction from the main control unit 70.

-Image input section-
The image input unit 60 includes a memory interface (I / F) 61 and a network (LAN) I / F 62 in addition to the ADF 110 and the scanner 120 shown in FIG. The memory I / F 61 reads image data to be printed from an external storage device such as a USB memory, a hard disk drive (HDD), or a solid state drive (SSD) through a video input terminal such as a USB port or a memory card slot. Alternatively, the image data captured by the scanner 120 is written to the storage device. The LAN I / F 62 is connected to an external LAN by wire or wirelessly, acquires image data to be printed from an electronic device on the LAN, or sends image data captured by the scanner 120 to the electronic device.

−Main control unit−
Main control unit 70 is an integrated circuit mounted on one printed circuit board installed inside MFP 100. Referring to FIG. 3, main controller 70 includes a CPU 71, a RAM 72, and a ROM 73. The CPU 71 is constituted by one MPU, and implements various functions as a control subject for the other elements 10, 20,..., 50, 60 by executing various firmware. For example, the CPU 71 displays a GUI screen such as an operation screen on the operation unit 50 to accept a user input operation. In response to this input operation, the CPU 71 determines an operation mode of the MFP 100 such as an operation mode, a standby mode, and a sleep mode, and instructs each element 10-60 to perform processing corresponding to the operation mode. The RAM 72 is a volatile semiconductor memory device such as a DRAM or SRAM, and provides a work area when the CPU 71 executes firmware to the CPU 71 and stores image data to be printed received by the operation unit 50. The ROM 73 is configured by a combination of a non-writable nonvolatile storage device and a rewritable nonvolatile storage device. The former stores firmware, and the latter includes a semiconductor memory device such as an EEPROM, flash memory, and SSD, or an HDD, and provides the CPU 71 with a storage area for environment variables and the like.

[Operation panel functions]
FIG. 4 is a functional block diagram of the operation panel 160. Referring to FIG. 4, the touch panel 170 is a multi-wire 4-wire resistive film system. Specifically, the touch panel 170 includes a timing control unit 431, a voltage / current monitoring unit 432, and an analog-digital (AD) conversion unit in addition to the elements shown in FIG. 1B, that is, the LCD 171, the touch pad 172, and the like. 433, a multi-touch determination unit 434, a distance measurement unit 435, and a coordinate calculation unit 436 are further included. These elements 431-436 are electronic circuit module groups, for example, mounted on a printed circuit board built in the operation panel 160, or incorporated in a single integrated circuit. Using these elements 431-436, the touch panel 170 detects a contact of the user's finger with the touch pad 172, and calculates the coordinates of the contact point.

  The control unit 53 functions as a user operation interpretation unit 531, a response control unit 532, a display control unit 533, and a vibration detection unit 534 by executing firmware stored in the nonvolatile memory device in the operation panel 160. The user operation interpretation unit 531 interprets a user input operation indicated by the touch pad 172 or the push button 161 and generates operation information. The response control unit 532 causes the touch panel 170 to realize the FFB function. Specifically, the response control unit 532 instructs the vibration generation unit 51 on the frequency distribution of the amplitude of the response vibration, that is, the spectrum, in response to detection of contact by the touch panel 170. When the vibration generating unit 51 drives the piezoelectric actuator 174 according to this instruction, a response vibration is applied to the touch pad 172. The display control unit 533 functions as a DSP for the LCD 171, the control circuit board 175, and the FPC 176. That is, the display control unit 533 processes the image data of the GUI screen in accordance with an instruction from the main control unit 70 and sends it to the control circuit board 175, and causes the FPC 176 to modulate the luminance of each pixel of the LCD 171 with the image data. Thereby, the GUI screen is reproduced in the display area of the touch panel 170. The vibration detection unit 534 monitors the output of the acceleration sensor 90 through the bus 80, and detects vibration generated at the installation location of the acceleration sensor 90 such as the chassis of the MFP 100 from the output. The vibration detection unit 534 particularly compares the amplitude of the vibration with a detection threshold value, and if the amplitude exceeds the detection threshold value, the vibration detection unit 534 regards the detected vibration as a background vibration and analyzes the spectrum.

The communication unit 440 connects the control unit 53 to the bus 80 so that communication is possible. Through this bus 80, the communication unit 440 receives instructions and image data from the main control unit 70, receives outputs from the acceleration sensor 90, and passes them to the control unit 53. At the same time, the communication unit 440 transmits operation information generated by the control unit 53 to the main control unit 70 through the bus 80.
-Touch detection by touch panel-
The touch pad 172 includes two transparent rectangular conductive films (for example, ITO thin films) 401 and 402. These conductive films 401 and 402 are stacked in parallel with a predetermined interval. The upper conductive film 401 includes the first electrode 421 and the second electrode 422 along each short side, and the electrical resistivity in the long side direction (X-axis direction in FIG. 4) is constant. The lower conductive film 402 includes a third electrode 423 and a fourth electrode 424 along each long side, and the electrical resistivity in the short side direction (Y-axis direction in FIG. 4) is constant. Any of the electrodes 421 to 424 is connected to the voltage / current monitoring unit 432 by a cable 177.

  The timing control unit 431 generates a timing signal TS having a constant frequency (for example, several tens of kHz) using a built-in clock and supplies the timing signal TS to the voltage / current monitoring unit 432. The voltage / current monitoring unit 432 alternately repeats the following operations (1) and (2) in synchronization with the timing signal TS. (1) A bias voltage is applied between the first electrode 421 and the second electrode 422 to monitor the amount of current between them, and the third electrode 423 and the fourth electrode 424 have a high impedance (that is, each The potentials of the conductive films 401 and 402 are monitored while maintaining the resistance value sufficiently higher than the resistance value of the entire conductive films 401 and 402. (2) A bias voltage is applied between the third electrode 423 and the fourth electrode 424 to monitor the amount of current between them, and the first electrode 421 and the second electrode 422 are kept in a high impedance state. Monitor the potential. The AD conversion unit 433 converts the analog value of the potential and the current amount measured by the voltage / current monitoring unit 432 into a digital value.

  The multi-touch determination unit 434 monitors the digital current amount output from the AD conversion unit 433, and notifies the coordinate calculation unit 436 of multi-touch detection if the current amount exceeds the reference value. This reference value corresponds to the first electrode 421 and the second electrode 422 when the two conductive films 401 and 402 are short-circuited at only one point during the period in which the voltage / current monitoring unit 432 performs the operation (1). In the period in which the operation (2) is performed, the amount of current between the third electrode 423 and the fourth electrode 424 in the same case is represented. When the two conductive films 401 and 402 are short-circuited at two or more points, current flows through both the conductive films 401 and 402 in parallel between the short-circuit points. Therefore, the resistance value between the first electrode 421 and the second electrode 422 decreases during the operation (1) period compared to the case where the short circuit between the conductive films 401 and 402 is at most one point, and the operation (2). During this period, the resistance value between the third electrode 423 and the fourth electrode 424 falls. As a result, the amount of current between each electrode pair 421-422, 423-424 exceeds the reference value. Therefore, this excess means that the short circuit between the conductive films 401 and 402 is two or more points, that is, multi-touch.

  The distance measuring unit 435 monitors the digital current amount output from the AD converting unit 433, and based on the current amount, the two short-circuits between the two conductive films 401 and 402 are two points. Estimate the distance between. As described above, when the short-circuit between the two conductive films 401 and 402 is two or more points, the first electrode 421 and the second electrode 422 are not connected in the period of the operation (1), compared with the case where the short circuit is at most one point. The resistance value between the third electrode 423 and the fourth electrode 424 decreases during the period of the operation (2). At this time, the amount of decrease in each resistance value is substantially determined by the distance between the two points when the short circuit between the two conductive films 401 and 402 is two points. Using this relationship, the distance measuring unit 435 estimates this distance from the difference between the current amount between each electrode pair 421-422, 423-424 and the reference value.

The coordinate calculation unit 436 monitors the digital values of the potentials of the electrodes 421,..., 424 output from the AD conversion unit 433, and determines the coordinates of the position where the user's finger touches the touch panel 170 from the potentials. Calculate as follows.
In the period in which the voltage / current monitoring unit 432 performs the operation (1), the bias voltage between the first electrode 421 and the second electrode 422 and the constant electrical resistivity cause the long side direction (X A constant potential gradient occurs in the axial direction. In this state, when the upper conductive film 401 is short-circuited with the lower conductive film 402 within a certain range, the third electrode 423 and the fourth electrode 424 are kept at high impedance, so that any of the electrodes 423 and 424 is maintained. Also, the potential substantially coincides with the center point of the short circuit range. The potential at the center point is determined by a voltage division ratio between the resistance between the first electrode 421 and the center point and the resistance between the center point and the second electrode 422. Since the potential gradient between the first electrode 421 and the second electrode 422 (X-axis direction) is constant, this voltage division ratio is the internal division ratio of the distance from the first electrode 421 to the second electrode 422 by this center point. That is, it is equal to the ratio of the distance from the first electrode 421 to the center point and the distance from the center point to the second electrode 422.

  Accordingly, the coordinate calculation unit 436 first detects a change in the potential at the third electrode 423 or the fourth electrode 424, the potential after the change, the potential of the first electrode 421 or the second electrode 422, and the bias therebetween. The voltage division ratio at the center point of the short circuit range is obtained from the voltage. Next, the coordinate calculation unit 436 calculates the distance between the center point and the first electrode 421 or the second electrode 422 from the voltage division ratio in the long side direction of the conductive films 401 and 402 (in FIG. (X coordinate). When the output of the multi-touch determination unit 434 does not indicate multi-touch detection, the coordinate calculation unit 436 outputs the coordinate of the center point as the coordinate (X coordinate) of the contact point in the long side direction of the conductive films 401 and 402. . On the other hand, when the output of the multi-touch determination unit 434 indicates multi-touch detection, the coordinate calculation unit 436 adds a half value of the distance output from the distance measurement unit 435 to the coordinates of the center point, and A value obtained by removing the half value from the coordinates is output as coordinates (X coordinates) of two contact points in the long side direction of the conductive films 401 and 402.

  During the period in which the voltage / current monitoring unit 432 performs the operation (2), the bias voltage between the third electrode 423 and the fourth electrode 424 and the constant electrical resistivity cause the short side direction ( A constant potential gradient occurs in the Y-axis direction). On the other hand, since the first electrode 421 and the second electrode 422 are maintained at high impedance, the potentials of the electrodes 421 and 422 substantially coincide with the center point of the short-circuit range. The potential at the center point is determined by a voltage division ratio between a resistance between the third electrode 423 and the center point and a resistance between the center point and the fourth electrode 424. The voltage division ratio is determined by the center point. It is equal to the internal ratio of the distance between the third electrode 423 and the fourth electrode 424.

  Therefore, the coordinate calculation unit 436 first detects a change in the potential of the first electrode 421 or the second electrode 422, the potential after the change, the potential of the third electrode 423 or the fourth electrode 424, and the bias therebetween. The voltage division ratio at the center point of the short circuit range is obtained from the voltage. Next, the coordinate calculation unit 436 obtains the distance between the center point and the third electrode 423 or the fourth electrode 424 from the voltage division ratio. The coordinate calculation unit 436 further determines the distance itself or the half value of the distance output from the distance measurement unit 435 depending on whether or not the output of the multi-touch determination unit 434 indicates multi-touch detection. The sum and difference are output as the coordinates (Y coordinate) of the contact point in the short side direction of the conductive films 401 and 402.

-Interpretation of user operations-
The user operation interpretation unit 531 compares the coordinates of the contact point received from the coordinate calculation unit 436 with the coordinates of gadgets such as virtual buttons and menu items included in the GUI screen, and estimates the user's operation target from among them. To do. The user operation interpretation unit 531 further identifies the type of gesture such as tap, flick, slide, rotation, etc. from the change in the coordinates of the contact point, and the user's gesture is determined based on this type and the gadget to be operated. Interpret the input operation to index. The user operation interpretation unit 531 also monitors whether or not various push buttons 161 on the operation panel 160 are pressed, identifies the push button 161 when any push button 161 is pressed, starts printing, Interpret the process associated with the button, such as stop. Based on the interpretation thus obtained, the user operation interpretation unit 531 generates operation information and notifies the main control unit 70 of the operation information.

-Spectrum of background vibration-
The background vibration is transmitted to the operation panel 160 through the casing of the MFP 100, and is applied to the touch panel 170, more precisely, the touch pad 172. At this time, the touch pad 172 resonates with a component that coincides with its own natural frequency among the frequency components included in the background vibration. Therefore, the spectrum of the background vibration is expressed by a combination of vibration levels for each natural frequency of the touch pad 172, for example, vibration intensity (medium acceleration).

  FIG. 5A is a list of nodal curves of the natural vibration mode (m = 1-3, n = 1-3) of the touch pad 172. In FIG. 5A, each rectangle represents the outline of the touch pad 172, and the boundary line between the white area and the shaded area is a natural vibration node, that is, the vibration level is constantly “0”. Represents a location. Since all sides of the touch pad 172 are fixed to the LCD 171, as shown in FIG. 5A, nodes appear as straight lines parallel to the long side or the short side inside the touch pad 172. The natural vibration mode is a pair (m, n) of a value m obtained by adding “1” to the number parallel to the long side and a value n obtained by adding “1” to the number parallel to the short side. In general, the larger the total number m + n−2 of the nodes, the higher the natural frequency.

  FIG. 5B is a schematic diagram showing the vibration modes of the natural vibration modes (m, n) = (1, 1), (1, 2), and (2, 1), and FIG. It is a graph of the vibration waveform in vibration mode. A curve indicated by (b) in FIG. 5 represents a contour line on the surface of the touch pad 172. The graph of FIG. 5C shows the change over time of the acceleration α indicated by one point on the surface along with the change in the height of the surface over time. Referring to FIG. 5B, in the lowest order natural vibration mode (m, n) = (1, 1), no node appears inside the touch pad 172. It vibrates in the line direction, and the height of each point on the surface changes in a sine wave shape. In the natural vibration mode (m, n) = (1, 2), (2, 1) with the next highest natural frequency, only one node appears on the inner side of the touch pad 172, and the surfaces on both sides sandwiching this node. The part vibrates in the normal direction with an antiphase. That is, when the surface portion on one side swells in a “mountain” shape, the surface portion on the opposite side is recessed in a “valley” shape. Within each surface portion, the height of each point changes in the same sine wave shape.

  FIG. 5D is a graph of a vibration waveform actually generated on the touch pad 172. Referring to FIG. 5D, the actual vibration waveform is quite complicated. However, this vibration is obtained by superimposing the sine wave shown in FIG. 5C with various amplitudes Δα between various natural vibration modes shown in FIG. Accordingly, any vibration that actually occurs on the touch pad 172 is expressed by a combination of the amplitudes Δα of the vibration strength α between the natural vibration modes (m, n).

  FIG. 5D further shows the detection threshold value Δαlim. The vibration detection unit 534 compares the detection threshold value Δαlim with the amplitude Δα of the vibration intensity α indicated by the output of the acceleration sensor 90. While any of these amplitudes Δα is equal to or smaller than detection threshold value Δαlim, vibration detection unit 534 assumes that MFP 100 is on standby. On the other hand, if the amplitude Δα exceeds the detection threshold Δαlim, the vibration detection unit 534 considers that the MFP 100 has started to operate, and analyzes the vibration spectrum indicated by the output of the acceleration sensor 90.

6A is a functional block diagram of the vibration detection unit 534, FIG. 6B is a graph showing a time waveform of background vibration indicated by the output of the acceleration sensor 90, and FIG. 6C is a graph showing the time waveform. It is a graph which shows the spectrum of the background vibration which the vibration detection part 534 analyzed.
As shown in FIG. 6A, the voltage signal VS output from the acceleration sensor 90 is received by the vibration detection unit 534. Since this voltage signal VS is proportional to the acceleration received by the weight in the acceleration sensor 90, that is, the intensity of the background vibration, a graph plotting the change over time, as shown in FIG. The time waveform of intensity αb is represented.

  The vibration detection unit 534 processes the voltage signal VS from the acceleration sensor 90 by the Fourier analysis unit 601. The Fourier analysis unit 601 performs a Fourier analysis on the voltage signal VS to obtain a frequency distribution with an amplitude Δαb as shown in FIG. Each frequency NRmn indicated by the horizontal axis in FIG. 6C represents the natural frequency of the touch pad 172. Thus, the spectrum of the background vibration is expressed by a combination of the vibration intensity Δαb for each natural frequency FRmn of the touch pad 172.

-Generation of response vibration (FFB)-
Referring to FIG. 4, the vibration generating unit 51 includes a driving unit 410. The drive unit 410 is a drive circuit for the piezoelectric actuator 174 and periodically applies a voltage to the piezoelectric actuator 174. In particular, the drive unit 410 matches the spectrum of the waveform of the voltage with the spectrum of the response vibration instructed from the response control unit 532. Thereby, the spectrum of the vibration applied from the piezoelectric actuator 174 to the touch pad 172 substantially matches the spectrum of the response vibration.

  The response control unit 532 sets the response vibration spectrum as follows. First, the response control unit 532 detects contact detection by the touch panel 170 from the fact that the user operation interpretation unit 531 has received the coordinates of the contact point from the coordinate calculation unit 436. When the user operation interpretation unit 531 estimates the operation target gadget in response to the reception, the response control unit 532 determines whether or not the gadget is a response target in vibration. As a response target by vibration, a virtual button or the like that should make the user feel the response when touching the gadget is selected. When the operation target gadget is a response object in vibration, the response control unit 532 confirms whether the vibration detection unit 534 has detected background vibration. If the vibration detection unit 534 has not detected the background vibration, the response control unit 532 sets the first spectrum as the response vibration spectrum. For example, the first spectrum shows a different pattern for each type of gadget to be responded to by vibration such as virtual buttons, menus, and toolbars, or for each type of gesture such as tap, flick, and slide. On the other hand, if the vibration detection unit 534 detects the background vibration, the response control unit 532 acquires the background vibration spectrum from the vibration detection unit 534. Based on the background vibration spectrum, the response control unit 532 transforms the first spectrum into the second spectrum and sets it as the response vibration spectrum.

  At this time, the response control unit 532 particularly sets a difference or ratio of vibration levels between the first spectrum and the second spectrum for each natural frequency of the touch pad 172. For this setting, for example, one of the following two methods (A) and (B) is adopted. (A) At least one of the vibration levels included in the spectrum of the background vibration is added to the vibration level of the same frequency component included in the first spectrum, and the obtained vibration is the same vibration included in the second spectrum. Set to the vibration level of several components. (B) A spectrum obtained by adding a frequency component not including the spectrum of the background vibration to the first spectrum is set as the second spectrum.

<First Method (A)>
FIG. 7 is a graph showing the first method (A). Referring to FIG. 7, the first spectrum of response vibration includes vibrations in addition to the natural vibration modes (m, n) = (1, 1), (1, 2), (2, 1),. An amplitude Δαr _{1 of} intensity α is set. The combination of the amplitudes Δαr ₁ between these natural vibration modes (m, n) is different for each type of gadget that is a response target in vibration or for each type of gesture. On the other hand, as the spectrum of the background vibration, as shown in FIG. 6C, the amplitude Δαb of the vibration intensity αb is calculated for each of the natural vibration modes (m, n) of the touch pad 172. The response control unit 532 first amplifies the amplitude Δαb of each frequency component of the background vibration: K1 × Δαb, amplification factor K1> 1. Next, the response control unit 532 adds each amplified amplitude Δαb to the amplitude Δαr ₁ of the same frequency component included in the first spectrum, and adds the sum Δαr ₁ + K1 × Δαb to the same frequency component included in the second spectrum. Is set to an amplitude Δαr ₂ of: Δαr ₂ = Δαr ₁ + K1 × Δαb.

As described above, in the first method (A), the value K1 × Δαb obtained by amplifying the amplitude Δαb of the background vibration is set to the amplitude difference Δαr ₂ −Δαr ₁ between the first spectrum and the second spectrum. In this case, even if the response vibration is accidentally in opposite phase to the background vibration, the amplitude after being canceled by the background vibration is larger than the amplitude Δαr ₁ indicated by the first spectrum.
The time for which the vibration generating unit 51 continues the response vibration is about several tens of milliseconds to several hundreds of milliseconds, which is longer than the typical duration of background vibration in any operation mode, that is, about several seconds to several tens of seconds. short. Actually, the duration of the background vibration in the print mode is equal to the time required to transport one sheet from the paper feed cassette 11 to the paper discharge tray 150 even if it is short. Even if the duration of the background vibration in the scan mode is short, it is equal to the time required for the slider 123 included in the scanner 120 to reciprocate once. The duration of the background vibration in the copy mode is substantially equal to the sum of the durations of the background vibration in the print mode and the background vibration in the scan mode.

Therefore, the amplitude of only the background vibration after the duration of the response vibration has elapsed from the composite amplitude, rather than the composite amplitude of the response vibration immediately after the touch and the background vibration itself, The change to is felt as the amplitude of the response vibration. That is, not the amplitude Δαr ₂ of the second spectrum itself but the difference Δαr ₂ −Δαb between it and the amplitude Δαb of only the background vibration spectrum is sensed by the user's finger. This perceived amplitude is greater than the first spectrum amplitude Δαr ₁ .

In this manner, the first method (A) can make the user's finger feel a response vibration stronger than when the MFP 100 is operating, even when the MFP 100 is operating, regardless of the background vibration.
<Second method (B)>
FIG. 8 is a graph showing the second method (B). Referring to FIG. 8, the amplitude Δαb of the vibration intensity α indicated by the background vibration spectrum is equal to or less than the threshold value Δαth for at least one (k, l) of the natural vibration modes (m, n) of the touch pad 172. This threshold value Δαth is set to a sufficiently small value with respect to a statistical representative value, such as a maximum value or an average value, among amplitudes Δαb indicated by a typical spectrum of background vibration. Therefore, when the amplitude Δαb of the frequency component having the background vibration is equal to or less than the threshold value Δαth, it can be considered that the spectrum of the background vibration does not substantially include the frequency component. Such a threshold value Δαth can be set for the background vibration spectrum in any operation mode of MFP 100.

When the response control unit 532 acquires the background vibration spectrum from the vibration detection unit 534, the response control unit 532 first searches for the natural vibration mode that is equal to or less than the threshold value Δαth from the amplitude Δαb indicated by the background vibration spectrum. Next, the response control unit 532 selects at least one (k, l) of the found natural vibration modes from those including the same frequency component in the first spectrum, and selects the selected natural vibration mode (k, l ), A spectrum obtained by adding the same frequency component to the first spectrum is set as the second spectrum. Specifically, the response control unit 532 first amplifies the amplitude Δαr ₁ of the same frequency component as that of the natural mode (k, l) included in the first spectrum to be larger than the threshold value Δαth: K2 × Δαr ₁ > Δαth , Amplification factor K2> 1. The response control unit 532 then sets the amplified value to the amplitude Δαr ₂ of the same frequency component as that of the natural vibration mode included in the second spectrum: Δαr ₂ = K2 × Δαr ₁ > Δαr ₁ .

As described above, in the second method (B), the second spectrum has a frequency component that does not substantially include the background vibration spectrum, and the amplitude Δαr ₂ is set sufficiently large. As described above, the duration of response vibration is shorter than the typical duration of background vibration in any operating mode. Therefore, the frequency component removed after the duration of the response vibration has elapsed from the frequency component included in the synthesis of the response vibration immediately after the contact and the background vibration is applied to the user's finger touching the operation screen. It is felt as a frequency component. That is, the frequency component given to the second spectrum by the second method (B) is reliably transmitted to the user's finger as a response vibration. Thus, in the second method (B), the response vibration can be clearly detected by the user's finger regardless of the background vibration even when the MFP 100 is operating.

[Flow of FFB processing by touch panel]
FIG. 9 is a flowchart of FFB processing by the touch panel 170. This process is started when the display unit 54 reproduces a GUI screen such as an operation screen in the display area of the touch panel 170 in accordance with an instruction from the main control unit 70, and is periodically performed while the GUI screen is displayed. For example, it is repeated every horizontal scanning period of the LCD 171, that is, at a frequency of several tens of kHz.

In step S101, the response control unit 532 determines whether or not the touch panel 170 has detected a contact with a user's finger or the like, specifically, whether or not the user operation interpretation unit 531 has received the coordinates of the contact point from the coordinate calculation unit 436. Confirm. If received, the process proceeds to step S102. If not received, the process ends.
In step S <b> 102, the user operation interpretation unit 531 receives the coordinates of the contact point from the coordinate calculation unit 436. Therefore, the response control unit 532 confirms whether or not the gadget of the user's operation target estimated by the user operation interpretation unit 531 is a response target in vibration based on the coordinates. If it is a response target, the process proceeds to step S103, and if it is not a response target, the process ends.

  In step S103, since the user's operation target gadget is a response target in vibration, the response control unit 532 determines whether the vibration detection unit 534 detects background vibration, specifically, the output of the acceleration sensor 90. It is confirmed whether any of the amplitudes Δα of the vibration intensity α shown exceeds the detection threshold value Δαlim. If any of the amplitudes Δα is equal to or smaller than the detection threshold value Δαlim, the process proceeds to step S104. If any of the amplitudes Δα exceeds the detection threshold value Δαlim, the process proceeds to step S105.

In step S104, since all of the amplitudes Δα are equal to or smaller than the detection threshold value Δαlim, it cannot be said that the vibration detection unit 534 detects the background vibration. Therefore, the response control unit 532 sets the first spectrum to the response vibration spectrum. Thereafter, the process proceeds to step S107.
In step S105, since any of the amplitudes Δα exceeds the detection threshold value Δαlim, it can be considered that the vibration detection unit 534 detects the background vibration. Therefore, the response control unit 532 acquires the background vibration spectrum from the vibration detection unit 534. Thereafter, the process proceeds to step S106.

In step S106, the response control unit 532 transforms the first spectrum into the second spectrum based on the background vibration spectrum acquired in step S105, and sets it to the response vibration spectrum. Thereafter, the process proceeds to step S107.
In step S107, the response control unit 532 instructs the drive unit 410 of the vibration generation unit 51 on the response vibration spectrum set in step S104 or step S106. Thereafter, the process proceeds to step S108.

In step S108, the response control unit 532 checks whether or not the duration of the response vibration instructed in step S107 has elapsed. If it has not yet elapsed, the process is repeated from step S103, and if it has already elapsed, the process ends.
-Flow of spectrum modification processing by the first method (A)-
FIG. 10 is a flowchart of a subroutine for transforming the response vibration spectrum by the first method (A) in step S106.

In step S111, the response control unit 532 selects the natural vibration modes (m, n) of the touch pad 172 one by one in order from the lowest natural frequency. Thereafter, the process proceeds to step S112.
In step S112, the response control unit 532 first uses the same spectrum as the natural vibration mode (m, n) selected in step S111 from the first spectrum of response vibration and the background vibration spectrum acquired from the vibration detection unit 534 in step S105. The amplitudes Δαr ₁ and Δαb of the frequency component are extracted. Next, the response control unit 532 amplifies the amplitude Δαb of the background vibration and adds it to the amplitude Δαr ₁ of the first spectrum, and adds the sum Δαr ₁ + K1 × Δαb to the amplitude Δαr ₂ of the same frequency component included in the second spectrum. Set: Δαr ₂ = Δαr ₁ + K1 × Δαb. Thereafter, the process proceeds to step S113.

In step S113, the response control unit 532 checks whether or not the natural frequency of the natural vibration mode (m, n) selected in step S111 has reached the upper limit. This upper limit is set in a range that can be sensed by the user's finger. If the natural frequency has not reached the upper limit, the process is repeated from step S111, and if it has reached, the process returns to step S107 shown in FIG.
-Flow of spectrum modification processing by the second method (B)-
FIG. 11 is a flowchart of a subroutine for transforming the response vibration spectrum by the second method (B) in step S107.

In step S121, the response control unit 532 selects the natural vibration modes (m, n) of the touch pad 172 one by one in order from the lowest natural frequency. Thereafter, the process proceeds to step S122.
In step S122, the response control unit 532 first extracts the amplitude Δαb of the same frequency component as the natural vibration mode (m, n) selected in step S121 from the background vibration spectrum acquired in step S105, which is the threshold value. Check if it is equal to or less than Δαth. If it is equal to or less than the threshold, the process proceeds to step S123, and if it exceeds the threshold, the process proceeds to step S127.

In step S123, since the amplitude Δαb extracted from the background vibration spectrum is equal to or smaller than the threshold value Δαth, it is determined whether or not the first spectrum includes the same frequency component as the natural vibration mode (m, n) selected in step S121. The response control unit 532 confirms. If so, the process proceeds to step S124. If not, the process proceeds to step S127.
In step S124, since the first spectrum includes the same frequency component as the natural vibration mode (m, n) selected in step S121, the response control unit 532 extracts the amplitude Δαr ₁ of the frequency component from the first spectrum. The amplification factor K2> 1 is set so that the value when it is amplified exceeds the threshold value Δαth: K2 × Δαr ₁ > Δαth. Thereafter, the process proceeds to step S125.

At step S125, the response control unit 532, the value K2 × Δαr ₁ after amplified in step S124 includes the second spectral amplitude Derutaarufaaru the same frequency component as the natural vibration mode selected in step S121 (m, n) ₂ set to _{be: Δαr 2 = K2 × Δαr 1} . Thereafter, the process proceeds to step S126.
In step S126, it is confirmed whether or not the number of amplitudes Δαr ₂ set in step S125 has reached the upper limit. This upper limit is set to be equal to or less than the total number of frequency components included in the first spectrum. If the number of amplitudes Δαr ₂ has not reached the upper limit, the process proceeds to step S127, and if it has reached, the process returns to step S107 shown in FIG.

In step S127, the response control unit 532 checks whether or not the natural frequency of the natural vibration mode (m, n) selected in step S121 has reached the upper limit. This upper limit is set in a range that can be sensed by the user's finger. If the natural frequency has not reached the upper limit, the process is repeated from step S121, and if it has reached, the process returns to step S107 shown in FIG.
[Advantages of the embodiment]
In MFP 100 according to the embodiment of the present invention, as described above, response control unit 532 of operation panel 160 is based on the background vibration spectrum detected by vibration detection unit 534 and the response vibration amplitude Δαr ₁ and the second spectrum indicated by the _first spectrum. difference or the display area of the specific operation screen amplitude Derutaarufaaru ₂ response vibration indicated, i.e. set for each natural oscillation mode of the touch pad 172 (m, n). This ensures that the user can detect the difference in vibration before and after superimposing the response vibration on the background vibration, regardless of the delay between the touch detection by the touch panel 170 and the response vibration output. The second spectrum can be set so that it can. In this way, operation panel 160 can cause the user to reliably detect the response vibration regardless of the background vibration accompanying the operation of MFP 100.

  In particular, in the first method (A), the response control unit 532 amplifies the vibration level of at least one of the frequency components of the background vibration and adds it to the vibration level of the same frequency component included in the first spectrum. In the second method (B), the frequency component that does not substantially contain the spectrum of the background vibration among the frequency components of the first spectrum is amplified. As a result, the response vibration is emphasized during the operation of MFP 100 more than during standby, so that the user can be surely sensed.

[Modification]
(A) The image forming apparatus 100 shown in FIG. 1A is an MFP. In addition, the image forming apparatus according to the embodiment of the present invention may be any single function machine such as a printer of another type such as a laser printer or an inkjet, a copier, a scanner, or a FAX.
(B) The touch panel 170 shown in FIG. 4 is a four-wire resistive film system compatible with multi-touch using two resistive films. In addition, the touch panel may be of any known method such as a five-wire resistive film method, a multi-touch compatible resistive film method using a matrix of a plurality of resistive films, a capacitance method, or an optical method. In any structure, the vibration generation unit can apply vibration to a touch pad to which a user should touch a finger or a protective member such as a sheet, film, or panel covering the touch pad.

  (C) The vibration generating unit 51 uses a pair of piezoelectric actuators 174 shown in FIG. 1B and FIG. 4 for exciting the touch pad 172. The piezoelectric actuator is not limited to the arrangement shown in these drawings, and may be arranged on all sides of the touch pad 172, for example. In addition to the piezoelectric actuator, the vibration generation unit may use an eccentric motor, a voice coil motor, or the like for exciting the touch pad 172.

(D) Each spectrum of the background vibration and the response vibration shown in FIG. 5-8 represents the vibration level by the vibration intensity α, that is, the acceleration of the medium. In addition, each spectrum may express the vibration level by the velocity or displacement of the medium.
(E) In the first method (A) shown in FIG. 7, the response control unit 532 adds the amplitude K1 × Δαb after amplification of the background vibration to the amplitude Δαr ₁ of the first spectrum itself, and the amplitude Δαr _{2 of} the second spectrum. Set to. In addition, the response control unit 532 may amplify the amplitude Δαr ₁ of the first spectrum and add it to the amplitude Δαb of the background vibration: Δαr ₂ = K3 × Δαr ₁ + K1 × Δαb, K3> 1. Accordingly, the response vibration is further emphasized during the operation of MFP 100 than during standby. Therefore, the operation panel can make the user's finger sense the response vibration more reliably during the operation of MFP 100 regardless of the background vibration.

(F) In the first method (A) shown in FIG. 7, the response control unit 532 amplifies all the amplitudes Δαb of the frequency components included in the background vibration spectrum, and the same frequency component included in the first spectrum. Add to the amplitude Δαr ₁ . In addition, the response control unit may select any one of the frequency components included in the spectrum of the background vibration, amplify only the amplitude thereof, and add it to the amplitude of the same frequency component included in the first spectrum. Good.

(G) In the second method (B) shown in FIG. 8, the response control unit 532 searches for the natural vibration mode having a threshold value Δαth or less from the amplitude Δαb of the frequency component of the background vibration, and among them, the same frequency component At least one (k, l) is selected from those included in the first spectrum. At this time, if the first spectrum does not include the same frequency component as any of those natural vibration modes, the response control unit 532 selects at least one (k, l) from those natural vibration modes, The same frequency component may be newly given to the second spectrum, and the amplitude Δαr ₂ may be set to a value larger than the threshold value Δαth.

  (H) In the second method (B), the response control unit 532 includes the natural vibration modes (m, n) = (1, 1), (1, 2) shown in FIG. 8 among the frequency components of the first spectrum. As described above, the same frequency component as that of the natural vibration mode in which the amplitude Δαb defined by the spectrum of the background vibration exceeds the threshold value Δαth is set to the same frequency component of the second spectrum as it is. In addition, the response control unit may exclude those frequency components from the second spectrum.

(I) Response control unit 532 changes the amplitude of each frequency component of the response vibration (including addition / removal of the frequency component) between the different operation modes depending on whether MFP 100 is on standby or in operation. ) To transform the spectrum. In addition, the response control unit may change the duration of the response vibration.
For example, when the scanner 120 scans a document placed on the platen glass 122, the duration of the background vibration is equal to the time required for the slider 123 to reciprocate once. Since this time is relatively short, the response control unit may extend the duration of the response vibration longer than this time. In this case, if the user's finger remains in contact with the touch pad 172 even after the slider 123 has finished reciprocating, the response vibration itself is transmitted to the finger.

Further, when the sheet conveyance interval in the print mode is set to be extremely long, there is a sufficient interval in which the vibration intensity α is kept sufficiently low in the waveform of the entire background vibration as shown in FIG. When it appears for a long time, the duration may be extended so that the interval easily overlaps with the duration of the response vibration.
(J) The operation unit 50 may allow the user to customize the response vibration. Specifically, the operation unit 50 may cause the display unit 54 to display a setting screen related to response vibration to be generated by the vibration generation unit 51 as a part of the operation screen. Through this setting screen, the operation unit 50 gives an indication (hereinafter referred to as a “preference index”) indicating the user's preference regarding the response vibration, such as the amount of increase / decrease in the amplitude of the response vibration, the upper and lower limit levels to be set to the amplitude. ). The operation unit 50 also causes the main control unit 70 to store the received preference index in the ROM 73 as one of environment variables. The response control unit 532 corrects the second spectrum according to these preference indices.

For example, the operation unit 50 allows the user to select one of three levels of indicators for response vibration intensity, “strong”, “medium”, and “weak”. The response control unit 532 corrects the amplitude Δαr ₂ of each frequency component defined by the second spectrum of the response vibration by +5 dB, 0 dB, or −5 dB according to these indices.
In addition, the operation unit 50 allows the user to set an upper limit Δαmax and a lower limit Δαmin for the amplitude of the response vibration. The response control unit 532 replaces the amplitude Δαr ₂ of the frequency component defined by the second spectrum of the response vibration with the upper limit Δαmax being replaced with the upper limit Δαmax, and with the lower limit Δαmin being replaced with the lower limit Δαmin.

  FIG. 12 is a process for increasing or decreasing the amplitude of the response vibration in accordance with the user's preference, compared to the process (see FIG. 10) for transforming the response vibration spectrum by the first method (A) in step S106 shown in FIG. It is a flowchart of a subroutine to which is added. Referring to FIG. 12, this process differs from the process shown in FIG. 10 only in that steps S131 to S133 are added between steps S112 and S113, and the other steps are the same. These similar steps are given the same reference numerals as those shown in FIG.

In step S111, the response control unit 532 selects the natural vibration modes (m, n) of the touch pad 172 one by one in order from the lowest natural frequency. Thereafter, the process proceeds to step S112.
In step S112, the response control unit 532 adds and amplifies the amplitude Derutaarufabi the same frequency component of the background vibration amplitude Derutaarufaaru ₁ of each frequency component of the first spectral response vibration, the sum Δαr ₁ + K1 × Δαb Set to the amplitude Δαr ₂ of the same frequency component of the second spectrum: Δαr ₂ = Δαr ₁ + K1 × Δαb. Thereafter, the process proceeds to step S131.

In step S <b> 131, the response control unit 532 accesses the main control unit 70, and reads the user preference index from among the environment variables stored in the ROM 73. If the response vibration intensity indicated by the preference index is “strong”, the process proceeds to step S132, if “medium”, the process proceeds to step S113, and if “weak”, the process proceeds to step S133.
In step S132, since the intensity of the response vibration indicated by the preference index is “strong”, the response control unit 532 corrects the amplitude Δαr ₂ of each frequency component defined by the second spectrum of the response vibration by +5 dB. Thereafter, the process proceeds to step S113.

In step S133, since the intensity of the response vibration indicated by the preference index is “weak”, the response control unit 532 corrects the amplitude Δαr ₂ of each frequency component defined by the second spectrum of the response vibration by −5 dB. Thereafter, the process proceeds to step S113.
In step S113, the intensity of the response vibration indicated by the preference index is “medium”, or the response control unit 532 has corrected the second spectrum of the response vibration according to the preference index. Therefore, the response control unit 532 checks whether or not the natural frequency of the natural vibration mode (m, n) selected in step S111 has reached the upper limit. If the natural frequency has not reached the upper limit, the process is repeated from step S111, and if it has reached, the process returns to step S107 shown in FIG.

  FIG. 13 shows a process of limiting the amplitude of the response vibration in accordance with the user's preference with respect to the process (see FIG. 10) for transforming the response vibration spectrum by the first method (A) in step S106 shown in FIG. It is a flowchart of a subroutine to which is added. Referring to FIG. 13, this process differs from the process shown in FIG. 10 only in that steps S141 to S144 are added between steps S112 and S113, and the other steps are the same. These similar steps are given the same reference numerals as those shown in FIG.

In step S111, the response control unit 532 selects the natural vibration modes (m, n) of the touch pad 172 one by one in order from the lowest natural frequency. Thereafter, the process proceeds to step S112.
In step S112, the response control unit 532 adds and amplifies the amplitude Derutaarufabi the same frequency component of the background vibration amplitude Derutaarufaaru ₁ of each frequency component of the first spectral response vibration, the sum Δαr ₁ + K1 × Δαb Set to the amplitude Δαr ₂ of the same frequency component of the second spectrum: Δαr ₂ = Δαr ₁ + K1 × Δαb. Thereafter, the process proceeds to step S141.

In step S <b> 141, the response control unit 532 first accesses the main control unit 70, and reads the user preference index from among the environment variables stored in the ROM 73. Next, the response control unit 532 has the same frequency component as the natural vibration mode (m, n) selected in step S111, which is defined by the upper limit Δαmax of the response vibration amplitude indicated by the preference index and the second spectrum of the response vibration. comparing of the amplitude Δαr _2, the amplitude Derutaarufaaru ₂ checks whether equal to or less than the upper limit Derutaarufamax. If it is less than or equal to the upper limit Δαmax, the process proceeds to step S143, and if it exceeds the upper limit Δαmax, the process proceeds to step S142.

In step S142, since the amplitude Derutaarufaaru ₂ in which the second spectral response vibration defines exceeds the upper limit Derutaarufamax, the response control unit 532 replaces the amplitude Derutaarufaaru ₂ to limit Derutaarufamax. Thereafter, the process proceeds to step S113.
In step S143, since the amplitude Δαr ₂ defined by the second spectrum of response vibration is equal to or lower than the upper limit Δαmax, the response control unit 532 continues to have the amplitude Δαr ₂ equal to or higher than the lower limit Δαmin of the amplitude of the response vibration indicated by the preference index. Check if it exists. If it is greater than or equal to the lower limit Δαmin, the process proceeds to step S113, and if it is less than the lower limit Δαmin, the process proceeds to step S144.

In step S144, since the amplitude Δαr ₂ defined by the second spectrum of the response vibration is below the lower limit Δαmin, the response control unit 532 replaces the amplitude Δαr ₂ with the lower limit Δαmin. Thereafter, the process proceeds to step S113.
In step S113, the response control unit 532 checks whether or not the natural frequency of the natural vibration mode (m, n) selected in step S111 has reached the upper limit. If the natural frequency has not reached the upper limit, the process is repeated from step S111, and if it has reached, the process returns to step S107 shown in FIG.

  (K) FIG. 14A is a graph showing a time waveform of vibration that can be detected by the vibration detection unit 534. Referring to FIG. 14A, these vibrations include not only background vibration BV accompanying the operation of MFP 100 but also sudden impact IM such as opening / closing of the door of MFP 100 and opening / closing of ADF 110. Is included. The typical duration ΔTb of the background vibration BV is about several seconds to several tens of seconds, while the duration ΔTi of the impact IM is about 100 milliseconds.

  The vibration detector 534 obtains a background vibration spectrum from the time waveforms of these vibrations BV and IM, and the response control section 532 deforms the response vibration spectrum based on the spectrum. In this case, it is unavoidable that a delay of about several tens of milliseconds occurs between the detection of contact by the touch panel 170 and the output of the response vibration. Since the duration ΔTb of the background vibration BV is sufficiently longer than this delay, the risk of the delay of the background vibration BV giving the user a sense of incongruity is low. However, since the duration ΔTi of the impact IM is about the same as this delay, if the response control unit 532 reflects these impacts as background vibrations in the second spectrum of the response vibration, the delay of the response vibration is There is a danger of giving a sense of incongruity.

Therefore, the response control unit 532 may exclude the vibration from the background vibration when the duration of the vibration detected by the vibration detection unit 534 is below the detection lower limit Δtmin. This detection lower limit Δtmin is determined by the minimum value of the background vibration duration. Since this minimum value generally differs for each operation mode of MFP 100, detection lower limit Δtmin is set for each operation mode of MFP 100.
FIG. 14B is a correspondence table between the operation mode of the MFP 100 and the detection lower limit Δtmin of the duration of the background vibration. Referring to FIG. 14B, the detection lower limit Δtmin for the copy mode and the print mode is 200 milliseconds, which is longer than the detection lower limit Δtmin for the scan mode and the FAX transmission mode. This is because the duration of the background vibration in each of the copy mode and the print mode is longer than the duration of the background vibration in each of the scan mode and the FAX transmission mode.

  FIG. 15 is a flowchart in the case where processing for excluding vibration having a duration shorter than the detection lower limit from background vibration is added to the FFB processing illustrated in FIG. 9. Referring to FIG. 15, this process differs from the process shown in FIG. 9 only in that step S110 is added between steps S103 and S105, and the other steps are the same. These similar steps are given the same reference numerals as those shown in FIG.

In step S <b> 101, the response control unit 532 confirms whether or not the user operation interpretation unit 531 has received the coordinates of the contact point from the coordinate calculation unit 436. If received, the process proceeds to step S102. If not received, the process ends.
In step S <b> 102, the user operation interpretation unit 531 receives the coordinates of the contact point from the coordinate calculation unit 436. Therefore, the response control unit 532 confirms whether or not the gadget that is the operation target of the user estimated by the user operation interpretation unit 531 is the response target in the vibration based on the coordinates. If it is a response target, the process proceeds to step S103, and if it is not a response target, the process ends.

  In step S103, since the gadget to be operated by the user is a response object in vibration, the response control unit determines whether any of the amplitudes Δα of the vibration intensity α indicated by the output of the acceleration sensor 90 exceeds the detection threshold value Δαlim. 532 confirms. If any of the amplitudes Δα is equal to or smaller than the detection threshold value Δαlim, the process proceeds to step S104. If any of the amplitudes Δα exceeds the detection threshold value Δαlim, the process proceeds to step S110.

In step S110, since any of the amplitudes Δα exceeds the detection threshold value Δαlim, the response control unit 532 further checks whether the duration of vibration indicated by the output of the acceleration sensor 90 exceeds the detection lower limit Δtmin. . If so, the process proceeds to step S105, and if below, the process proceeds to step S104.
In step S104, since any of the amplitudes Δα is equal to or smaller than the detection threshold Δαlim, or even when any of the amplitudes Δα exceeds the detection threshold Δαlim, the vibration duration is equal to or smaller than the detection lower limit Δtmin, the response control unit 532 Sets the first spectrum to the spectrum of the response vibration. Thereafter, the process proceeds to step S107.

In step S105, since any one of the amplitudes Δα exceeds the detection threshold value Δαlim and the vibration duration exceeds the detection lower limit Δtmin, the response control unit 532 acquires the background vibration spectrum from the vibration detection unit 534. Thereafter, the process proceeds to step S106.
In step S106, the response control unit 532 transforms the first spectrum into the second spectrum based on the background vibration spectrum acquired in step S105, and sets it to the response vibration spectrum. Thereafter, the process proceeds to step S107.

In step S107, the response control unit 532 instructs the drive unit 410 of the vibration generation unit 51 on the response vibration spectrum set in step S104 or step S106. Thereafter, the process proceeds to step S108.
In step S108, the response control unit 532 checks whether or not the duration of the response vibration instructed in step S107 has elapsed. If it has not yet elapsed, the process is repeated from step S103, and if it has already elapsed, the process ends.

  The present invention relates to an operation panel, and as described above, the response vibration spectrum during operation of the apparatus equipped with the operation panel is transformed from the response vibration spectrum during standby based on the background vibration spectrum detected during the operation. To do. Thus, the present invention is clearly industrially applicable.

100 MFP
160 Operation Panel 161 Push Button 170 Touch Panel 171 LCD
172 Touchpad 173 Cover 174 Piezoelectric actuator 175 Control circuit board 176 FPC
177 cable 50 operation unit 51 vibration generation unit 53 control unit 54 operation unit display unit 90 acceleration sensor 401 conductive film on the upper side of the touch pad 402 conductive film on the lower side of the touch pad 421 first electrode 422 on the touch pad 2 electrodes 423 3rd electrode of touch pad 424 4th electrode of touch pad 410 Drive unit 431 of piezoelectric actuator 431 Timing control unit 432 Voltage / current monitoring unit 433 AD conversion unit 434 Multi-touch determination unit 435 Distance measurement unit 436 Coordinate calculation unit 531 User operation interpretation unit 532 Response control unit 533 Display control unit 534 Vibration detection unit

Claims (7)

An operation panel that is mounted on a device that vibrates in operation, displays an operation screen of the device and accepts a user operation on the operation screen,
A touch panel that includes a display area of the operation screen, and detects contact of the external object with the display area;
A vibration generator for applying vibration to the display area;
During the operation of the device, a vibration detection unit that detects vibration associated with the operation and obtains a spectrum of the vibration as a spectrum of background vibration;
When the vibration detection unit detects background vibration in response to the touch panel detecting the contact, and confirms whether the vibration generation unit detects the background vibration. Is a response control unit that applies a vibration indicating the first spectrum to the display area as a response to the contact, respectively, when the vibration detection unit detects a background vibration. When,
With
The response control unit calculates a difference or ratio of vibration levels between the first spectrum and the second spectrum for each natural frequency of the display region based on a spectrum of background vibration detected by the vibration detection unit. An operation panel characterized by being set to   The response control unit amplifies at least one of the vibration frequency components included in the spectrum of the background vibration and adds it to the vibration level of the same frequency component included in the first spectrum, and the obtained sum is obtained. The operation panel according to claim 1, wherein the operation level is set to a vibration level of the same frequency component included in the second spectrum.   The operation panel according to claim 1, wherein the response control unit sets a spectrum obtained by adding a frequency component that does not include a background vibration spectrum to the first spectrum as the second spectrum. . The operation screen includes a setting screen related to vibration to be generated by the vibration generation unit,
The operation panel according to any one of claims 1 to 3, wherein the response control unit corrects the second spectrum in accordance with a user operation on the setting screen.   The operation panel according to claim 4, wherein the correction of the second spectrum by the response control unit includes an increase or decrease in vibration level, or an upper limit or lower limit setting for the vibration level. A storage unit storing a minimum value of the background vibration duration for each operation mode of the device;
The response control unit identifies the operation mode of the device at the time of detection in response to the touch panel detecting the contact, and the duration of the background vibration detected by the vibration detection unit at the time of detection is the operation mode. 6. The method according to claim 1, further comprising: causing the vibration generation unit to apply vibrations indicating the first spectrum to the display region as a response to the contact when the value is lower than a minimum value in the display. The operation panel described in Crab. An image forming unit for forming an image on a sheet;
The operation panel according to any one of claims 1 to 6, wherein an operation screen for the image forming unit is displayed to accept a user operation on the operation screen;
An image forming apparatus comprising:

Images