Image processing device including touch panel and touch panel erroneous detection processing method

Abstract

To reduce erroneous operations of a capacitive touch panel applied to an image processing device installed in a noisy environment at a level of control software of the image processing device.SOLUTION: An image processing device includes: a capacitive touch panel unit that detects one or more touch operations and provides information on a position of each touch operation and information on whether or not a region of each touch operation is equal to or smaller than a predetermined area; a control unit that determines the operation on the basis of those pieces of information; and an image processing unit that executes image processing on the basis of the determination. The control unit determines the operation on the basis of the information on the position if each region is equal to or smaller than the predetermined area, and ignores all the one or more detected touch operations if any region is larger than the predetermined area.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present disclosure relates to an image processing device equipped with a touch panel and a method for processing erroneous detection on a touch panel. [Background technology]

[0002] Touch panels are widely used in information processing devices such as tablet terminals and smartphones, but in recent years they have also been applied to image processing devices such as multifunction peripherals that have many operation items. By displaying an operation screen using a liquid crystal display panel or the like and detecting touch operations on the operation screen with the touch panel, it is possible to present to the user operation items that correspond to the current situation among the many operation items. There are various types of touch panels, but one of the representative types that is also used in tablet terminals and smartphones is the capacitive touch panel. It has features such as being able to detect touch operations at two or more points at the same time, being able to be made small and thin due to its relatively simple configuration, and being highly durable.

[0003] When a part of the palm of a user's hand is detected close to the touch panel while inputting data to a smartphone, or when the palm of a user's hand touches the touch panel while inputting data to a tablet device using a pen, a touch area larger than the fingertip or pen tip may be detected. Such a large touch area is not considered to be the touch operation intended by the user. When a touch area larger than a certain area is detected, the touch area is ignored, and only touch areas smaller than the certain area are considered valid.

[0004] In order to reduce malfunctions caused by unintended touches by a user, for example, the following electronic device has been proposed. The electronic device has an attitude detection means for detecting the attitude of the electronic device, a touch detection means for detecting a touch on a touch panel, a control means for controlling the target area of ​​the touch panel to be different depending on the attitude detected by the attitude detection means, and a function execution means. The function execution means does not execute a function corresponding to the touch if the touch area on the target area is equal to or larger than a threshold, and executes a function corresponding to the touch if the touch area on the target area is smaller than the threshold. Note that for touches on areas that are not the target area, the function corresponding to the touch is not executed regardless of whether the touch area is equal to or larger than the threshold (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-212805 A Summary of the Invention [Problem to be solved by the invention]

[0006] As is the case with many electronic devices in recent years, the detection of touch operations using a capacitive touch panel device is achieved by combining the touch panel hardware, touch detection circuit ICs (integrated circuits), and software processing to provide the touch panel function. The software processing is usually modularized and hierarchical in consideration of the possibility of reusing it for different purposes. In other words, it is rare for a single company to develop the hardware and software for a touch panel device. Usually, the development of the touch panel, the touch detection circuit, and the software modules related to touch operation detection at each layer, from the layer close to the hardware to the application layer, are shared among different entities.

[0007] Measures to ignore the detection of touch operations unintended by the user or to prevent erroneous detection of touch operations should be taken by the touch panel hardware, touch detection circuit, and each software module, respectively. This is because it is efficient to take measures against problems common to specific hardware regardless of the purpose or use environment in the hardware or a software module at a layer close to the hardware. Similarly, this is because it is efficient to take measures against problems common to specific touch detection circuits regardless of the purpose or use environment in the detection circuit or a software module related to detection circuit control. On the other hand, it is efficient to take measures against problems that occur in a specific purpose or use environment in a software module at a layer close to the application. In general, it can be said that software developers at a layer closer to application development than software developers at a layer closer to the hardware can easily obtain information from devices used for specific purposes or in specific environments and their users. In other words, application device developers can easily obtain information from end users than unit developers. It is convenient if measures against problems that occur in specific purposes or use environments can be closed by software modules at a layer closer to the application.

[0008] The present disclosure has been made in consideration of the above circumstances, and provides a method for reducing malfunctions of a capacitive touch panel applied to an image processing device installed in a noisy environment, at the level of the control software of the image processing device. [Means for solving the problem]

[0009] The present disclosure provides an image processing device comprising: a capacitive touch panel unit that detects one or more touch operations and provides information relating to the position of each touch operation and information relating to whether the area of ​​each touch operation is equal to or smaller than a predetermined area; a control unit that determines the operation based on that information; and an image processing unit that performs image processing based on the determination, wherein the control unit determines the operation based on the information relating to the position if each area is equal to or smaller than a predetermined area, and ignores the one or more detected touch operations if any area is larger than the predetermined area.

[0010] Also, from a different perspective, the present disclosure provides a method for processing erroneous detection of a touch panel, comprising the steps of: a control unit of an image processing device detecting one or more touch operations using a capacitive touch panel unit that provides information related to the position of the touch operation and information related to whether the area of ​​the touch operation is equal to or smaller than a predetermined area; determining the operation based on the information related to the detected touch operation; and executing image processing based on the determination using an image processing unit, wherein the control unit determines the operation based on the information related to the position when each area of ​​the one or more touch operations is equal to or smaller than a predetermined area, and ignores all of the detected one or more touch operations when any area is larger than the predetermined area. Effect of the Invention

[0011] In the image processing device according to the present disclosure, if each area of ​​the touch operation is less than a predetermined area, the control unit determines the operation based on position information, and if any area is larger than the predetermined area, the control unit ignores one or more detected touch operations. Therefore, malfunctions of a capacitive touch panel applied to an image processing device installed in a noisy environment can be reduced at the level of the control software of the image processing device. The touch panel erroneous detection processing method according to the present disclosure also achieves the same advantageous effects. [Brief description of the drawings]

[0012] [Figure 1] 1 is a block diagram showing a configuration example of an image processing device according to the present disclosure. [Diagram 2] 2 is an explanatory diagram showing a configuration example of a capacitive touch panel that is applied to the touch panel shown in FIG. 1. [Diagram 3] 3 is an explanatory diagram showing a transparent electrode of a part of the touch panel shown in FIG. 2. [Figure 4] 4 is an explanatory diagram showing the detection principle of the touch panel shown in FIG. 3. [Diagram 5]3 is an explanatory diagram showing a configuration example of a detection chip 36 including a sensor line driving unit and a sensor line detection unit shown in FIG. 2. FIG. [Figure 6] 3 is a graph showing an example of touch detection by the horizontal touch operation detection unit shown in FIG. 2 , both raw and after zero correction (no touch operation under normal circumstances); [Figure 7] 3 is a graph showing an example of touch detection by the horizontal touch operation detection unit shown in FIG. 2 , both raw and after zero correction (when a normal touch operation is performed); [Figure 8] 3 is a graph showing an example of touch detection by the horizontal touch operation detection unit shown in FIG. 2 before and after zero correction (no touch operation in an abnormal state); [Figure 9] 3 is a graph showing an example of touch detection by the horizontal touch operation detection unit shown in FIG. 2 (when an abnormal touch operation is present); [Figure 10] 10 is a first flowchart illustrating an example of a process for reducing erroneous detection of a touch operation executed by an operation control unit illustrated in FIG. [Figure 11] 10 is a second flowchart illustrating an example of the process of reducing erroneous detection of a touch operation executed by the operation control unit illustrated in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The present disclosure will be described in further detail below with reference to the drawings. Note that the following description is illustrative in all respects and should not be construed as limiting the present disclosure. <Configuration example of image processing device> Fig. 1 is a block diagram showing an example of the configuration of an image processing device according to the present disclosure. The image processing device 100 shown in Fig. 1 includes an image processing unit 10, a control unit 20, and an operation unit 30. The image processing unit 10 includes a document reading unit 11 and a printing unit 12, and the control unit 20 includes an operation control unit 21 and a job processing unit 22. The document reading unit 11 is an image scanner having an image sensor, and reads an image of a document. The printing unit 12 is a printer engine unit using an electrophotographic method or an inkjet method, etc., and forms an image based on image data and prints it on printing paper.

[0014] The control unit 20 controls image processing by using electronic circuits, mainly composed of a processor and memory as hardware, and a control program, as software, that causes the processor to execute processing. The operation control unit 21 displays an operation screen on the operation unit 30, accepts a user's touch operation on the operation screen, and performs processing according to the touch operation. The job processing unit 22 performs processing to have the image processing unit 10 execute a job related to image processing, such as a copy job, a scan job, or a print job, based on the touch operation accepted by the operation control unit 21. The operation section 30 includes a display processing section 38, a display device 39, and a touch panel unit 31. The display device 39 is a display device mainly composed of a display panel such as an LCD (Liquid Crystal Display) or an OLED (Organic Light Emitting Display). The display processing section generates a display image of an operation screen based on an instruction from the operation control section 21, and performs processing to display the image on the display device 39. The touch panel unit 31 includes a touch panel 32, a touch operation detection section 33, and a touch processing section 34.

[0015] (Embodiment 1) <Touch panel unit configuration example and touch operation detection principle> FIG. 2 is an explanatory diagram showing a configuration example of a capacitive touch panel applied to the touch panel 32 shown in FIG. 1. The capacitive touch panel 32 is formed by stacking a first transparent electrode sheet 32X, in which a plurality of transparent electrodes are arranged in the X-axis direction (horizontal direction), and a second transparent electrode sheet 32Y, in which a plurality of transparent electrodes are arranged in the Y-axis direction (vertical direction), via an insulating layer (not shown). The touch panel 32 is disposed in an area on the display device 39 where a touch operation is detected. For example, in the case of the transparent electrode sheet 32X shown in FIG. 2, a plurality of diamond-shaped transparent electrode cells arranged in the vertical direction are connected to each other to form one transparent electrode group extending in the vertical direction. A plurality of such transparent electrode groups are arranged in the horizontal direction. In the case of the transparent electrode sheet 32Y, a plurality of diamond-shaped transparent electrode cells arranged in the horizontal direction are connected to each other to form one transparent electrode group extending in the horizontal direction. A plurality of such transparent electrode groups are arranged in the vertical direction.

[0016] Each diamond-shaped transparent electrode constituting the transparent electrode group is an electrode of a capacitor related to detection of a touch operation. When a user's finger touches the transparent electrode, the mutual capacitance between the transparent electrode of transparent electrode sheet 32X and the transparent electrode of transparent electrode sheet 32Y at that position decreases, and the change in capacitance is detected.

[0017] FIG. 3 is an explanatory diagram showing some transparent electrodes of the touch panel 32 shown in FIG. 2. Two of the four diamonds shown in FIG. 3 arranged in the Y-axis direction represent two transparent electrodes in the transparent electrode sheet 32X, which are connected to the sensor line driving unit 33X shown in FIG. 2 through the same driving side line and belong to the same transparent electrode group. The other two diamonds arranged in the X-axis direction represent two transparent electrodes in the transparent electrode sheet 32Y, which are connected to the sensor line detection unit 33Y shown in FIG. 2 through the same detection side line and belong to the same transparent electrode group. The transparent electrodes of the transparent electrode sheet 32Y are capacitively coupled with the transparent electrodes of the transparent electrode sheet 32X, and the coupling capacitance (mutual capacitance) is shown as Cm in FIG. 3. FIG. 4 is an explanatory diagram showing the detection principle of the touch panel shown in FIG. 3. The upper diagram of FIG. 4 shows a state in which the touch panel 32 is not touched, and the lower diagram shows a state in which the touch panel 32 is touched by a finger F. The sensor line driving unit 33X applies a pulsed voltage to the transparent electrodes of the transparent electrode sheet 32X through the driving side line. The dashed line from the driving side transparent electrode to the detection side transparent electrode shows the electric field E generated between the transparent electrodes by the applied voltage. The driving side transparent electrode and the detection side transparent electrode of the touch panel 32 are covered with a cover layer 32C made of a transparent dielectric. When a finger F approaches the touch panel 32, the electric field from the electrode is absorbed by the fingertip. Therefore, the mutual capacitance Cm between the driving side transparent electrode and the detection side transparent electrode is reduced compared to the state where the finger F is not present. The sensor line detection unit 33Y connected to the detection side electrode via the detection side line detects the amount of charge stored in the transparent electrode of the second transparent electrode sheet 32Y by the voltage applied to the driving electrode side, and therefore the magnitude of the mutual capacitance Cm. The amount of charge detected by the sensor line detection unit 33Y is processed by the processor of the touch processing unit. In this embodiment, the hardware of the touch operation detection unit 33 including the sensor line driving unit 33X, the sensor line detection unit 33Y, and the touch processing unit is integrated into the detection chip 36.

[0018] FIG. 5 is an explanatory diagram showing a configuration example of the detection chip 36. As shown in FIG. 5, the sensor line driving unit 33X sequentially applies pulsed voltages at different timings to a plurality of driving side lines aligned in the X-axis direction. This causes repeated scanning of the driving side transparent electrode rows aligned in the X-axis direction of the first transparent electrode sheet 32X. The sensor line detection unit 33Y detects the amount of charge generated in each detection side transparent electrode aligned in the Y-axis direction through the mutual capacitance Cm in the detection side transparent electrode rows aligned in the Y-axis direction of the second transparent electrode sheet 32Y by the pulsed voltages applied to each driving side line at different timings. As shown in FIG. 3, the sensor line detection unit 33Y converts each input from the plurality of detection side lines aligned in the Y-axis direction into digital data using an A / D conversion circuit (ADC) and inputs it to a DSP (Digital Signal Processor). The DSP detects the magnitude of the amount of charge during scanning for each detection side transparent electrode aligned in the X-axis direction and Y-axis direction, and outputs it to the touch processing unit 34. The processor of the touch processing unit 34 judges the presence or absence of a touch and the position of the touch based on the charge amount that changes depending on the presence or absence of the proximity of the finger F, that is, the change in the mutual capacitance Cm. To make this judgment, the processor of the touch processing unit 34 detects the magnitude of the charge amount of each transparent electrode during scanning when the finger F is not in proximity to the touch panel 32, therefore the magnitude of the mutual capacitance Cm, and stores it in advance in memory as a zero reference value. This is calibration. The magnitude of the charge amount of each transparent electrode detected each time scanning is performed is also called the touch detection amount. The processor of the touch processing unit 34 corrects the magnitude of the charge amount of each transparent electrode with the zero reference value (zero correction), and judges the presence or absence of a touch and the position of the touch based on the touch detection amount after the zero correction. Furthermore, it also judges whether or not to output a large object status. Then, it transmits the result of the judgment to the operation control unit 21.

[0019] <Touch operation detection>

[0020] FIG. 6 is a graph showing an example of detection of the raw touch detection amount in the horizontal direction of the touch panel 32 by the touch processing unit 34 shown in FIG. 5 and the touch detection amount after zero correction. Although not shown in FIG. 6, the touch processing unit 34 also performs processing related to the vertical direction of the touch panel 32 in the same manner. The graph on the left side shown in FIG. 6 shows the raw touch detection amount at each position (each driving side transparent electrode) in the horizontal direction of the touch panel 32. The dashed line shown in FIG. 6 shows the zero reference value stored in the memory by calibration. On the other hand, the solid line shows the raw touch detection amount detected at the present time. The graph on the right side shows the touch detection amount after zero correction. The touch detection amount after zero correction is the difference between the raw touch detection amount detected at the present time and the zero reference value. In other words, the zero reference value is used as the origin of the Y axis of the graph to show the touch detection amount at each point (each transparent electrode) of the X coordinate. FIG. 6 shows a state where no touch operation is performed, and the graph on the left side shows that the touch detection amount at the present time and the zero reference value almost match. In the graph on the left, the current touch detection amount after zero correction almost coincides with zero on the Y axis of the graph.

[0021] FIG. 7 shows how the touch detection amount changes from FIG. 6 when a touch operation is performed. As in FIG. 6, the graph on the left shows the raw touch detection amount, and the graph on the right shows the touch detection amount corrected to zero. As shown in FIG. 7, a peak appears at the touch position in the current touch detection amount, and a difference occurs with the zero reference value. The touch processing unit 34 determines the position of the touch panel 32 corresponding to the position of the peak of the X coordinate of the graph as the horizontal position of the touch position. Although not shown, the vertical position of the touch position of the touch panel 32 is determined in the same manner. The touch operation detection unit 33 outputs information related to the determined horizontal and vertical directions of the touch panel 32 to the control unit 20 as a touch report. Note that, if the width of the peak is wider than the reference, the touch operation detection unit 33 outputs a large object status to the control unit 20 instead of a touch report.

[0022] <Touch panel false detection and how to reduce it> A method for reducing false detection of the touch panel according to this embodiment will be described. As described above, the touch processing unit 34 performs zero correction of the touch detection amount using a zero reference value. By doing so, it is possible to prevent the influence of stationary noise and offset. However, when an image processing device installed in a noisy environment is used in a specific situation, false detection may occur. Examples of situations in which false detection occurs include the following factors. First, the image processing device is installed in an electromagnetic environment in which the touch panel 32 receives large noise. As an example of receiving large noise from the surroundings, the image processing device may receive noise from an external device connected to the image processing device via a communication line, such as a switching hub of a LAN. In addition, the signal or power voltage of an external device to which the signal or power is connected to the image processing device may fluctuate, causing fluctuations in the power supply or ground of the image processing device, which may become noise. In addition, the ground line of the AC power cord of the image processing device may not be connected to the ground of the AC outlet, or the ground pattern of the secondary circuit may have poor contact with the housing ground, making the ground level of the secondary circuit unstable. In such cases, the image processing device may be more susceptible to noise.

[0023] Secondly, there is a case where a correct zero reference value cannot be obtained when performing calibration. The touch panel 32 requires timely calibration to correct sensitivity fluctuations in charge amount detection for each detection side line caused by fluctuations in ambient temperature, etc. However, if calibration is performed in an environment with a large amount of noise and while the touch panel is being touched, a correct zero reference value cannot be obtained. If a correct zero reference value cannot be obtained, the result of zero correction using that zero reference value will also be an abnormal value.

[0024] Thirdly, when frequency hopping is performed, the correct zero reference value associated with the frequency hopping cannot be obtained. This is also related to the above-mentioned calibration. The touch panel has a noise removal function for removing various noises, one of which is frequency hopping. The sensor line driving unit 33X drives the driving side line at a constant scanning frequency, and the sensor line detection unit 33Y repeatedly detects the charge amount of each transparent electrode in synchronization with the scanning frequency. Noise of a frequency different from the scanning frequency can be removed by averaging. However, noise synchronized with the scanning frequency cannot be removed by averaging. Therefore, the touch panel also has a function to change the scanning frequency according to the situation. In other words, if noise synchronized with the scanning frequency occurs, the touch panel cannot remove the noise. To deal with this, when it is determined that noise of such a frequency has been detected, the touch processing unit 34 changes the scanning frequency to avoid the influence of the noise synchronized with the scanning frequency. Since the zero reference value depends on the scanning frequency, it is necessary to obtain a zero reference value corresponding to each different scanning frequency. During calibration, a zero reference value is acquired for each scanning frequency that may be changed, and when changing the scanning frequency by frequency hopping, the zero reference value is switched to the zero reference value corresponding to the changed scanning frequency. Zero correction is performed using the zero reference value corresponding to the changed scanning frequency, and touch processing is continued. Here, if the zero reference value corresponding to the changed scanning frequency cannot be correctly acquired, the result of zero correction using that zero reference value will also be an abnormal value.

[0025] FIG. 8 is a graph showing an example of detection of the raw touch detection amount and the touch detection amount after zero correction when such adverse conditions overlap and the original zero reference value cannot be obtained. This is a graph of the touch detection amount in an abnormal state corresponding to the touch detection amount when the normal zero reference value shown in FIG. 6 is obtained. As shown in FIG. 8, when the original zero reference value cannot be obtained and an abnormal zero reference value is detected, the touch processing unit 34 uses the abnormal value for the subsequent zero correction of the touch detection amount, resulting in an erroneous determination. In FIG. 8, the influence of noise is small at the present time, and the touch detection amount equivalent to that of FIG. 6 is detected at the present time. However, because the zero reference value is abnormal, it is erroneously determined that a touch operation has been performed in a certain area even though no touch operation has been performed.

[0026] FIG. 9 shows a case where an abnormal zero reference value similar to that of FIG. 8 is detected, and a touch operation similar to that of FIG. 7 is detected. That is, at this point in time, the influence of noise is small, and the touch detection amount is detected to be the same as that of FIG. 6. However, because the zero reference value is abnormal, it is erroneously determined that a touch operation has been performed even in an area where no touch operation has been performed. In this way, the inventor has found that in the case of erroneous determination caused by a combination of factors such as external noise and touch operation during calibration, abnormal values ​​tend to appear not only in small areas such as touch operations by fingers, but also over large areas. It is presumed that this occurs because, when a strong noise that affects touch detection is received, the frequency hopping function becomes active and the zero reference value is switched to a different scanning frequency, and the zero reference value is changed to an abnormal zero reference value when calibration is performed by mistake due to external noise.

[0027] Therefore, in this embodiment, attention is paid to the fact that the above-mentioned erroneous detection tends to occur over a larger area than touch operation by a finger. When such a large area is touched, the touch processing unit 34 outputs a large object status instead of a touch report. The large object status is originally intended for, for example, when the palm of the user's hand touches the touch panel during pen input or when the user holds a smartphone, and is not due to external noise. However, writing with a pen on the operation unit of a device such as an image processing device is not expected, and the operation unit is not conceivable to be held. Therefore, when the large object status is output, the operation control unit 21 that receives information from the touch panel unit 31 discards and ignores all touch reports received in that state. By doing so, it is possible to prevent the touch panel unit 31 from being affected even if a erroneous detection occurs.

[0028] <<Processing for reducing false detection of touch operation executed by operation control unit>> The process of reducing erroneous detection of a touch operation executed by the control unit 20 as the operation control unit 21 will be described below. As shown in Fig. 1, the operation control unit 21 receives a touch report and a large object status as information related to a touch operation from the touch processing unit 34 of the touch panel unit 31. The touch report notifies information related to the position of a touch operation when one or more touch operations of a predetermined area or less are detected. The large object status notifies the state when a touch operation of an area larger than a predetermined area is detected.

[0029] 10 and 11 are flowcharts showing an example of a process for reducing false detection of a touch operation executed by the control unit 20 as the operation control unit 21. The operation control unit 21 repeatedly executes the processes shown in FIG. 10 and FIG. 11. As shown in FIG. 10, the operation control unit 21 waits for information related to the detection of a touch operation, that is, either a touch report or a large object status, to be sent from the touch processing unit 34 (loop of No in step S11). Note that, while the process for waiting for reception is shown in a loop in FIG. 10, the control unit 20 executes other processes related to the control of the image processing device in a multitasking manner during that time. When the operation control unit 21 receives a touch report or a large object status (Yes in step S11), it temporarily stores the received information in a memory (step S13). This is a dedicated storage area for determining a touch operation.

[0030] Then, the operation control unit 21 judges whether the touch panel unit 31 is currently detecting a large object (step S15). That is, it judges whether the large object status is detected from the touch processing unit 34 (the ON state has been received most recently) or the large object status is not detected (the ON state has not been received or the OFF state has been received most recently). If the large object status is not detected (No in step S15), it judges whether the information received in step S11 and stored in the memory is the ON state of the large object status (step S17). If the ON state of the large object status has been received (Yes in step S17), the current state is updated to the state in which the large object status is detected (ON state) (step S19).

[0031] It is assumed that the current state of the large object status is stored in the memory. While the current state of the large object status is ON, the operation control unit 21 determines that even if a touch report is received from the touch processing unit 34, it is highly likely to be a false detection due to noise, and ignores (discards) the received touch report (step S21). Then, the processing for that round is terminated.

[0032] On the other hand, if it is determined in step S17 that the information received from the touch processing unit 34 is not related to the large object status (No in step S17), the operation control unit 21 makes the following determination. It is determined whether the information received from the touch processing unit 34 in the above-mentioned step S11 is a touch report or not (step S31 shown in FIG. 11). If a touch report is received (Yes in step S31), the operation control unit 21 determines whether or not a process is required for each of one or more touch positions included in the received touch report, and if a process is required, executes the process as required (step S33), and ends the process. The process as required may be, for example, a process for changing the operation screen, a process for setting a job, or a process for instructing the job processing unit 22 to execute a job. If the received information is not a touch report (step S31), the process ends without executing any process related to the received information.

[0033] Also, in the judgment of step S15, if the touch panel unit 31 is currently in a state where a large object is detected (Yes in step S15), the operation control unit 21 judges whether the information received in step S11 and stored in the memory is an OFF state of the large object status (step S23). If the OFF state of the large object status is received (Yes in step S23), the current state is updated to a state where the large object status is not detected (OFF state) (step S25). While the current state related to the large object status is OFF, the operation control unit 21 performs processing related to the touch operation based on the touch report received from the touch processing unit 34. Specifically, the process proceeds to step S31 shown in FIG. 11, and the operation control unit 21 judges whether the information received from the touch processing unit 34 in the above-mentioned step S11 is a touch report. If the touch report is received (Yes in step S31), the operation control unit 21 judges whether or not a process is required for each of one or more touch positions included in the received touch report, and if a process is required, executes the process as required (step S33), and ends the process. If the received information is not a touch report (step S31), the process ends without processing the received information. The above is an example of the process for reducing erroneous detection of a touch panel executed by the control unit 20 in this embodiment.

[0034] (Embodiment 2) When the large object status continues to be ON for a period of time exceeding a predetermined period of time, or when the large object status is detected at a frequency exceeding a predetermined standard, the touch processing unit 34 may warn the user that the zero reference value of the touch detection amount may not be normal. The calibration for obtaining the zero reference value of the touch detection amount needs to be performed when the user is not performing a touch operation on the touch panel 32, so it is necessary to inform the user. The warning may be displayed on the operation screen by the operation control unit 21. Based on the instruction of the warning, the user may perform an operation such as turning the power off / on.

[0035] (Embodiment 3) Instead of or in addition to the execution mode of the calibration according to the second embodiment, for example, the touch processing unit 34 may autonomously execute the calibration related to acquisition of a zero reference value of the touch detection amount in a standby state after the end of a job. During the execution of the calibration, the operation control unit 21 may cause the display device 39 to display a warning message to not perform a touch operation while the calibration related to acquisition of the zero reference value is being executed.

[0036] It should be understood that the present disclosure also includes any combination of the above-described aspects. In addition to the above-described embodiment, various modifications of the present disclosure are possible. These modifications should not be interpreted as not belonging to the scope of the present disclosure. The invention according to the present disclosure should include all modifications that are equivalent to the scope of the claims and that belong to the scope of the present disclosure. [Explanation of symbols]

[0037] 10: image processing unit, 11: document reading unit, 12: printing unit, 20: control unit, 21: operation control unit, 22: job processing unit, 30: operation unit, 31: touch panel unit, 32: touch panel, 32C: cover layer, 32X, 32Y: transparent electrode sheet, 33: touch operation detection unit, 33X: sensor line driving unit, 33Y: sensor line detection unit, 34: touch processing unit, 36: detection chip, 38: display processing unit, 39: display device, 100: image processing device

Claims

1. a capacitive touch panel unit that detects one or more touch operations and provides information on the position of each touch operation and information on whether an area of ​​each touch operation is equal to or smaller than a predetermined area; A control unit that determines an operation based on the information; an image processing unit that performs image processing based on the determination, The control unit of the image processing device determines an operation based on information relating to the position when each area is less than a predetermined area, and ignores one or more detected touch operations when any area is larger than the predetermined area.

2. 2. The image processing device according to claim 1, wherein the touch panel unit provides information relating to the position of the touch operation when the area of ​​the touch operation is equal to or smaller than a predetermined area, and provides information informing the user that a touch area larger than the predetermined area has been detected when the area of ​​the touch operation is larger than the predetermined area.

3. 2. The image processing device according to claim 1, wherein the touch panel unit pre-stores in memory the amount of touch detection when no touch operation is performed as a zero reference value, uses the zero reference value to correct the amount of touch detection detected at each subsequent point in time, and determines the position of each touch operation and whether the area of ​​each touch operation is equal to or smaller than a predetermined area based on the corrected amount of touch detection.

4. the touch panel unit provides information to the control unit when a touch area larger than the predetermined area is detected, and provides information to the control unit when a touch area larger than the predetermined area is no longer detected, 2. The image processing device according to claim 1, wherein the control unit ignores any one or more detected touch operations from the time when the control unit receives information from the touch panel unit that a touch area larger than the specified area has been detected until the control unit receives information that a touch area larger than the specified area is no longer detected.

5. 2. The image processing device according to claim 1, wherein the control unit warns a user that the zero reference value of the touch detection amount may not be normal when a state in which a touch area larger than the specified area is detected continues for more than a predetermined time or is detected with a frequency exceeding a predetermined standard.

6. A control unit of the image processing device Detecting one or more touch operations using a capacitive touch panel unit that provides information on the position of the touch operation and information on whether an area of ​​the touch operation is equal to or smaller than a predetermined area; determining an operation based on the information related to the detected touch operation; and executing image processing using an image processing unit based on the determination. The control unit determines an operation based on information relating to the position when each area of ​​the one or more touch operations is equal to or smaller than a predetermined area, and ignores the one or more detected touch operations when any area is larger than the predetermined area.

Images