Input device and image forming apparatus

Abstract

To provide an input device and an image formation device that reduce malfunction caused by noise on an operation panel having both a capacitive touch panel and a touch button.SOLUTION: When a second detection unit detects a touch operation on a touch button, a touch time measurement unit measures time from the touch operation to a state of no-touch operation. When the measurement time is shorter than on / off effective time, or when there is a predetermined number of times or more of touch operations within a predetermined time that is longer than long press effective time, a malfunction determination unit determines that the touch operation detected by the second detection unit is malfunction. When the malfunction determination is made, a control unit sets a button baseline value stored in a button baseline value storage unit to an initial value. On the other hand, when the malfunction determination unit does not determine that there is the malfunction (if the touch operation is normal), the control unit sets a panel baseline value stored in a panel baseline value storage unit as an initial value.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a capacitive touch panel, an input device provided with touch buttons, and an image forming apparatus.

Background Art

[0002] Capacitive touch panels and touch buttons have been used in recent years as interfaces for various electronic devices and apparatuses. Such touch panels and touch buttons measure the capacitance between an indicator such as a user's finger or a touch pen, and detect the presence or absence of a touch operation based on the difference between the measured capacitance and a baseline value. Patent Document 1 describes a technique related to an apparatus provided with a plurality of capacitive touch panels.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Capacitive touch panels and touch buttons are susceptible to the influence of electrical noise, and thus noise countermeasures are required. For example, noise can be reduced by grounding the apparatus, but there are many cases where grounding is not performed. Even if grounding is performed, noise cannot be completely eliminated, and noise countermeasures are necessary. Further, when both a touch panel and touch buttons are provided on an operation panel, noise countermeasures are required for both.

[0005] An object of the present invention is to reduce malfunction due to noise of an operation panel having both a capacitive touch panel and touch buttons.

Means for Solving the Problems

[0006] An input device according to one aspect of the present invention comprises: a capacitive touch panel; a capacitive touch button; a first measuring unit for measuring the capacitance between the touch panel and an indicator; a second measuring unit for measuring the capacitance between the touch button and an indicator; a first detection unit for detecting the touch position of the indicator on the touch panel based on the difference between the capacitance measured by the first measuring unit and a baseline value for the panel; a second detection unit for detecting whether or not a touch operation has been performed on the touch button based on the difference between the capacitance measured by the second measuring unit and a baseline value for the button; a malfunction determination unit for determining that the touch operation detected by the second detection unit is a malfunction if the touch operation detected by the second detection unit satisfies predetermined conditions; and a control unit for setting the baseline value for the button to a predetermined initial value if the malfunction determination unit determines that the touch operation detected by the second detection unit is a malfunction, and for setting the baseline value for the panel to a predetermined initial value if the malfunction determination unit does not determine that the touch operation is a malfunction. [Effects of the Invention]

[0007] According to the present invention, if the malfunction detection unit determines that a touch operation to a touch button is a malfunction, the control unit sets the baseline value for the button to its initial value. If the unit does not determine that the operation is a malfunction (normal touch operation), the control unit sets the baseline value for the panel to its initial value. As a result, each time the user operates a touch button, the control unit sets the baseline value for the panel to its initial value, preventing false touch detections on the touch panel caused by the panel baseline value being updated after being affected by noise.

[0008] Furthermore, while home buttons have traditionally been mechanical, using a capacitive touchscreen requires noise countermeasures for both the touch button and the touch panel. The present invention makes it possible to implement noise countermeasures for both the touch panel and the touch button. [Brief explanation of the drawing]

[0009] [Figure 1]This is a front cross-sectional view showing the structure of an image forming apparatus. [Figure 2] This is a block diagram showing the electrical configuration of an image forming apparatus. [Figure 3] This is a block diagram showing the electrical configuration of a touch panel device and a touch button device. [Figure 4] This diagram shows an example of the content displayed on the display unit. [Figure 5] This diagram illustrates the initialization process for baseline values ​​for panels and buttons. [Modes for carrying out the invention]

[0010] Hereinafter, an input device and an image forming apparatus according to one embodiment of the present invention will be described with reference to the drawings. Figure 1 is a front cross-sectional view showing the structure of an image forming apparatus equipped with an input device according to one embodiment of the present invention.

[0011] The image forming apparatus 1 according to one embodiment of the present invention may be a multifunction device that combines multiple functions such as a copy function, a printer function, a scanner function, and a facsimile function, or it may be a copier equipped with a scanner function. In this embodiment, an image forming apparatus using an electrophotographic method is described as an example, but it may also be an image forming apparatus using other methods such as an inkjet method.

[0012] The image forming apparatus 1 comprises an image reading device 11, an operation panel 20, an image forming unit 12, a fixing unit 15, a paper feeding unit 14, and a document feeding unit 6, etc. The operation panel 20 is located on the front of the main body of the apparatus. The operation panel 20 displays operation screens and messages, and includes a display unit 21 which is integrated with a capacitive touch panel 221. In addition, it includes touch buttons 231 which are capacitive touch buttons, etc. Although not shown, it may also include hard keys with other functions.

[0013] The display unit 21 consists of a liquid crystal display (LCD) or an organic light-emitting diode (OLED) display, etc.

[0014] When the image reading device 11 performs a scanning operation, the image reading unit 5 optically reads the image of the document fed by the document feeding unit 6 or the document placed on the first platen glass 161, and acquires the document image. The document image acquired by the image reading unit 5 is stored in the image memory 91, which will be described later.

[0015] When the image forming apparatus 1 performs a printing operation, the image forming unit 12 forms a toner image on the paper P fed from the paper feeding unit 14 based on the original image acquired by the scanning operation and image data acquired from an external device via the communication control unit 93 (described later).

[0016] When performing color printing, the magenta image forming unit 3M, the cyan image forming unit 3C, the yellow image forming unit 3Y, and the black image forming unit 3Bk of the image forming unit 12 each form a toner image on the photoreceptor drum 4 through charging, exposure, and development processes based on an image consisting of the respective color components that make up the image data, and then transfer the toner image onto the intermediate transfer belt 125 by the primary transfer roller 126.

[0017] The toner images of each color transferred onto the intermediate transfer belt 125 are superimposed on the intermediate transfer belt 125 by adjusting the transfer timing, resulting in a color toner image. The secondary transfer roller 210a transfers the color toner image formed on the surface of the intermediate transfer belt 125 to the paper P transported from the paper feeding unit 14 at the nip section N between the intermediate transfer belt 125 and the drive roller 210b.

[0018] Next, the fuser unit 15 fixes the toner image on the paper P by thermal pressure. The color image formed on the paper P after the fixing process is completed is discharged into the output tray 17.

[0019] The paper feeding unit 14 includes a plurality of paper feeding cassettes. The control unit 101, which will be described later, rotationally drives the pickup roller 145 of any one of the paper feeding cassettes to convey the paper P accommodated in each paper feeding cassette toward the nip portion N.

[0020] FIG. 2 is a block diagram showing the electrical configuration of the image forming apparatus 1. The description of the components described using FIG. 1 is omitted.

[0021] The storage unit 92 is a large-capacity storage device composed of an SSD and an HDD that store image data, various programs, data tables, and the like.

[0022] The communication control unit 93 is composed of a communication module and the like, and performs transmission and reception of various data with an external device via a network connected to the communication control unit 93.

[0023] The control unit 100 is composed of a processor, a RAM (Random Access Memory), a ROM (Read Only Memory), and the like. The processor is a CPU (Central Processing Unit), an MPU, or an ASIC, etc. By the processor executing a control program stored in the ROM or the like, the control unit 100 functions as the control unit 101, the first detection unit 223, the second detection unit 233, and the malfunction determination unit 236, which will be described later. The control unit 101 is in charge of the overall operation control of the image forming apparatus 1. Note that the control unit 101, the first detection unit 223, the second detection unit 233, and the malfunction determination unit 236 may each be constituted by a hardware circuit without depending on the operations according to the control program by the control unit 100. Hereinafter, unless otherwise particularly noted, the same applies to each embodiment.

[0024] [[ID=2l]]The operation panel 20 includes a display unit 21, a touch panel device 22 having a touch panel 221, and a touch button device 23 having a touch button 231. The input device 2 in the present invention is constituted by including the operation panel 20 and the control unit 101.

[0025] Figure 3 is a block diagram showing the electrical configuration of the touch panel device 22 and the touch button device 23. Figure 4 is an external view of the operation panel 20. The touch panel device 22 includes a touch panel 221 and a first measuring unit 222. The panel baseline value storage unit 224 is a storage device that stores the panel baseline value, and is, for example, a non-volatile memory built into the control unit 100. Multiple capacitance sensors (not shown) are arranged in a matrix direction on the touch panel 221. The first measuring unit 222 measures the capacitance of each capacitance sensor arranged on the touch panel 221. The first measuring unit 222 is, for example, a capacitance measurement circuit using the constant current discharge method, or a circuit that has the same function as a tester. The first detection unit 223 calculates the difference between the measurement value acquired by the first measuring unit 222 and the panel baseline value stored in the panel baseline value storage unit 224, and detects the touch position based on whether the difference is greater than or equal to a threshold.

[0026] The touch button device 23 includes a touch button 231 and a second measuring unit 232. The button baseline value storage unit 234 is a storage device that stores the baseline value for the button, and is, for example, a non-volatile memory built into the control unit 100. The touch time measurement unit 235 measures the time that the touch button 231 is touched (pressed), and is, for example, a timer built into the control unit 100. The touch button 231 is a capacitive button (e.g., a home button) consisting of a hard key that the user frequently operates, and has a capacitive sensor (not shown) on it.

[0027] The second measurement unit 232 measures the capacitance of the capacitance sensor located on the touch button 231. The second measurement unit 232 is, for example, a capacitance measurement circuit using the constant current discharge method, or a circuit that has the same function as a tester. The second detection unit 233 detects a touch operation on the touch button 231 based on the capacitance of the capacitance sensor measured by the second measurement unit 232. Furthermore, the second detection unit 233 calculates the difference between the measurement value acquired by the second measurement unit 232 and the baseline value for the button stored in the button baseline value storage unit 234, and detects whether or not a touch operation has been performed on the touch button 231 based on whether or not the difference is greater than or equal to a threshold, and outputs the detection result to the malfunction determination unit 236.

[0028] Ta Time measurement unit 235 teeth The second detection unit 233 measures the time from when it detects a touch operation on the touch button 231 until it detects a state where there is no touch operation.

[0029] The malfunction determination unit 236 determines whether or not a detection error occurred in the second detection unit 233, based on the detection result output by the second detection unit 233 and the time measured by the touch time measurement unit 235.

[0030] Specifically, the touch time measurement unit 235 measures the time from when the second detection unit 233 detects a touch operation on the touch button 231 until it detects a state with no touch operation. If this time is shorter than a predetermined on / off valid time (for example, a time set between 0.01 and 0.05 seconds) or longer than a predetermined long-press valid time (for example, a time set between 0.1 and 5.0 seconds), the malfunction determination unit 236 determines that the touch operation detected by the second detection unit 233 is a malfunction. Furthermore, if the detection result output by the second detection unit 233 is more than a predetermined number of times within a predetermined time (for example, 5 times within a predetermined time of 1 second), the malfunction determination unit 236 determines that the touch operation detected by the second detection unit 233 is a malfunction.

[0031] The baseline value is, for example, the capacitance value of the capacitive sensor (measured by the first measurement unit 222 and the second measurement unit 232) when the user's finger or a stylus or other indicator is not in contact with the touch panel 221 or touch button 231 (when there is no touch operation). The first measurement unit 222 measures the capacitance value when there is no touch operation, and the panel baseline value storage unit 224 updates and stores that capacitance value as the panel baseline value. Similarly, the second measurement unit 232 measures the capacitance value when there is no touch operation, and the button baseline value storage unit 234 updates and stores that capacitance value as the button baseline value. These update processes are performed periodically by instruction from the control unit 101.

[0032] The difference calculated by the first detection unit 223 and the second detection unit 233 (measured capacitance - baseline value) will be close to 0 if there is no touch operation on the touch panel 221 or touch button 231, and will be a large value if there is a touch operation. The first detection unit 223 and the second detection unit 233 detect the presence or absence of a touch by comparing this difference with a predetermined threshold, so if the baseline value is not appropriate, a correct touch operation cannot be performed.

[0033] However, capacitive touch panels 221 and touch buttons 231 are susceptible to electrical noise. If the baseline value is updated by the update process while under the influence of noise, the relationship between the difference and the threshold may change, potentially leading to false touch detection. This can be mitigated by, for example, grounding the image forming apparatus 1, but many users do not ground it.

[0034] Therefore, initial values ​​for the baseline value for the panel and the baseline value for the buttons are determined in advance, and when predetermined conditions are met, the control unit 101 resets the baseline values ​​stored in the panel baseline value storage unit 224 and the button baseline value storage unit 234 to their initial values. This makes it possible to keep each baseline value at an appropriate value at all times, even if the image forming apparatus 1 is not grounded, and enables correct detection of touch operations on the touch panel 221 and the touch buttons 231.

[0035] The initialization process for the baseline values ​​for the panel and buttons in this embodiment will be described in detail below. Figure 5 is a flowchart illustrating the flow of this initialization process. In addition to the initialization process for the baseline values ​​for the panel and buttons described below, it is desirable to simultaneously perform the update process that has been carried out in the past, where the capacitance value of the touch panel 221 when there is no touch operation is set as the baseline value for the panel, and the capacitance value of the touch button 231 when there is no touch operation is set as the baseline value for the button.

[0036] First, when the second detection unit 233 detects a touch operation of the touch button 231, the touch time measurement unit 235 measures the time from that touch operation until the second detection unit 233 detects a state without a touch operation. If the time measured by the touch time measurement unit 235 is shorter than a predetermined on / off valid time (S11; YES), the malfunction determination unit 236 determines that the touch operation detected by the second detection unit 233 is a malfunction. This occurs, for example, when the touch button 231 is repeatedly turned on and off at a speed that is impossible to achieve with human movement.

[0037] Due to noise interference, the second detection unit 233 may detect on / off operations of the touch button 231 at intervals too short for a human finger to operate. Therefore, the shortest touch operation that a human can operate is pre-set as the on / off valid time, and if the time of the touch operation detected by the second detection unit 233 is shorter than the on / off valid time, the malfunction determination unit 236 determines that the touch operation is a malfunction.

[0038] Furthermore, if the time measured by the touch time measurement unit 235 is longer than the predetermined long-press validity period (S12; YES), the malfunction determination unit 236 determines that the touch operation detected by the second detection unit 233 is a malfunction.

[0039] Due to noise interference, the second detection unit 233 may detect a long-press touch operation on the touch button 231 even when the user is not operating it. Therefore, a long-press validity period is set in advance, and if the duration of the touch operation detected by the second detection unit 233 is longer than the long-press validity period, the malfunction determination unit 236 determines that the touch operation is a malfunction.

[0040] Furthermore, if the second detection unit 233 detects a predetermined number of touch operations (repeated taps) within a predetermined time (S13; YES), the malfunction determination unit 236 determines that the touch operation is a malfunction.

[0041] If the malfunction detection unit 236 determines that a malfunction has occurred (S11; YES, S12; YES, S13; YES), the control unit 101 sets the button baseline value stored in the button baseline value storage unit 234 to its initial value (S15). The initial value of the button baseline value is stored in advance in a non-volatile memory, for example, built into the control unit 100, which is accessible to the control unit 101.

[0042] If the touch operation detected by the second detection unit 233 is normal, that is, if the malfunction determination unit 236 does not determine that it is a malfunction (S11; NO, S12; NO, S13; NO), the control unit 101 sets the panel baseline value stored in the panel baseline value storage unit 224 to the initial value (S14). The initial value of the panel baseline value is stored in advance in a non-volatile memory, for example, built into the control unit 100, which is accessible to the control unit 101.

[0043] In other words, if a malfunction occurs in the touch button 231, the control unit 101 rewrites the baseline value for the button in the button baseline value storage unit 234 to its initial value. On the other hand, if the touch operation of the touch button 231 is performed normally by the user, the control unit 101 rewrites the baseline value for the panel in the panel baseline value storage unit 224 to its initial value.

[0044] Since the touch panel 221 accepts operation inputs necessary for the operation and settings of the image forming apparatus 1, if there is a false touch detection due to noise, the image forming apparatus 1 will not operate correctly. Therefore, in addition to the conventional update process that sets the capacitance value of the touch panel 221 when there is no touch operation as the baseline value for the panel, the control unit 101 sets the baseline value for the panel to an initial value each time the touch button 231 (home button), which is frequently operated by the user, is touched. This prevents false detections of the touch panel 221 due to the baseline value of the panel being updated under the influence of noise.

[0045] Furthermore, while home buttons were conventionally often mechanical, using a capacitive touch system for both the touch button 231 and the touch panel 221 necessitates noise countermeasures for both the touch button 231 and the touch panel 221. As explained above, when the malfunction detection unit 236 determines that the second detection unit 233 has detected a false positive, the control unit 101 sets the baseline value for the button to an initial value, and if the touch operation of the touch button 231 is normal, it sets the baseline value for the panel to an initial value, thereby enabling noise countermeasures for both the touch panel 221 and the touch button 231. [Explanation of Symbols]

[0046] 1. Image forming apparatus 2 Input devices 5 Image reading unit 12 Image forming unit 20 Control Panel 21 Display section 22 Touch panel device 221 Touch Panel 222 First measurement section 223 First detection unit 224 Baseline value storage unit for panel 23 Touch button device 231 Touch buttons 232 Second measurement section 233 Second detection unit 234 Baseline value storage unit for buttons 235 Touch time measurement unit 236 Malfunction determination section 100 control units 101 Control Unit

Claims

1. Capacitive touch panel, Capacitive touch buttons, A first measuring unit for measuring the capacitance between the touch panel and the indicator, A second measuring unit for measuring the capacitance between the touch button and the indicator, A first detection unit detects the touch position of the indicator on the touch panel based on the difference between the capacitance measured by the first measurement unit and the baseline value for the panel, A second detection unit detects whether or not a touch operation has been performed on the touch button based on the difference between the capacitance measured by the second measurement unit and the baseline value for the button, A malfunction determination unit determines that if the touch operation detected by the second detection unit satisfies predetermined conditions, the touch operation detected by the second detection unit is a malfunction. An input device comprising: a control unit that, when the malfunction determination unit determines that a touch operation detected by the second detection unit is a malfunction, sets the baseline value for the button to a predetermined initial value; and when the malfunction determination unit does not determine that a touch operation is a malfunction, sets the baseline value for the panel to a predetermined initial value.

2. The input device according to claim 1, further comprising a touch time measurement unit that measures the time from when the second detection unit detects a touch operation on the touch button until it detects a state without a touch operation, wherein if the time measured by the touch time measurement unit is shorter than a predetermined on / off effective time, the malfunction determination unit determines that the touch operation detected by the second detection unit is a malfunction.

3. The input device according to claim 1, further comprising a touch time measurement unit that measures the time from when the second detection unit detects a touch operation on the touch button until it detects a state of no touch operation, wherein if the time measured by the touch time measurement unit is longer than a predetermined long-press valid time, the malfunction determination unit determines that the touch operation detected by the second detection unit is a malfunction.

4. The input device according to claim 1, wherein if the second detection unit detects a predetermined number of touch operations within a predetermined time, the malfunction determination unit determines that the touch operations detected by the second detection unit are malfunctions.

5. The input device according to claim 1, wherein the touch button is a home button.

6. An input device according to any one of claims 1 to 5, An image forming unit that prints an image onto paper, An image forming apparatus equipped with [a specific feature].

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