Recording material detection device, image forming apparatus, and ultrasonic emission device

Abstract

The present disclosure relates to a recording material detection apparatus, an image forming apparatus, and an ultrasonic transmitting apparatus. The recording material detection apparatus includes: an ultrasonic sensor including a transmitting unit that transmits ultrasonic waves and a receiving unit that receives ultrasonic waves, the transmitting unit and the receiving unit being arranged opposite to each other across a conveyance path through which a recording material is conveyed; an instruction unit that supplies a first driving input or a second driving input larger than the first driving input to the transmitting unit; and a detection unit that detects information on a grammage of the recording material based on a first value obtained by the receiving unit receiving ultrasonic waves transmitted from the transmitting unit to which the first driving input is supplied and not passing through a recording medium, and a second value obtained by the receiving unit receiving ultrasonic waves transmitted from the transmitting unit to which the second driving input is supplied and passing through the recording medium.

Description

Technical Field

[0001] The present invention generally relates to the basis weight (grams per square meter) of recording materials using ultrasound. 2 )) detection. Background Technology

[0002] Image forming apparatuses are configured to form images on recording materials having various characteristics such as size, basis weight, and surface properties. Japanese Patent Application Publication No. 2004-219856 discusses an image forming apparatus that includes a recording material detection device for identifying the type of recording material (hereinafter referred to as "paper type") in order to perform image forming associated with such recording material. The recording material detection device includes, for example, a transmitting unit that emits ultrasonic waves and a receiving unit that receives ultrasonic waves arranged opposite each other across a transport path through which the recording material is transported. The recording material detection device causes the transmitting unit to emit ultrasonic waves toward the recording material and causes the receiving unit to receive the ultrasonic waves transmitted through the recording material, thereby providing a method for identifying the paper type using the received ultrasonic wave level. In such a recording material detection device that uses ultrasonic waves to detect the basis weight of the recording material, the detection result may vary depending on the environment in which the recording material detection device is placed. Therefore, Japanese Patent No. 6,399,747 discusses a method for detecting basis weight based on the received level obtained by the receiving unit receiving ultrasonic waves that do not pass through the recording material and the received level obtained by the receiving unit receiving ultrasonic waves that pass through the recording material. In this method, the received level obtained by receiving ultrasound waves passing through the recording material through the receiving unit is less than the received level obtained by receiving ultrasound waves not passing through the recording material through the receiving unit. Therefore, the amplification of the received level obtained by receiving ultrasound waves passing through the recording material through the receiving unit is greater than the amplification of the received level obtained by receiving ultrasound waves not passing through the recording material through the receiving unit.

[0003] However, increasing the amplification of the received ultrasonic wave level by the receiving unit also amplifies noise present in the circuitry that receives the ultrasonic wave. Therefore, noise may reduce the accuracy of the detection of information regarding weight. Summary of the Invention

[0004] According to one aspect of the present invention, a recording material detection apparatus includes: an ultrasonic sensor comprising a transmitting unit for emitting ultrasonic waves and a receiving unit for receiving ultrasonic waves, the transmitting unit and the receiving unit being arranged opposite to each other across a transport path through which the recording material is transported; an indicating unit configured to input a first driving input to the transmitting unit for causing the transmitting unit to emit ultrasonic waves having a first maximum amplitude or to input a second driving input for causing the transmitting unit to emit ultrasonic waves having a second maximum amplitude greater than the first maximum amplitude; and a detection unit configured to detect information about the weight of the recording material based on a first value obtained by receiving ultrasonic waves emitted from the transmitting unit supplied with the first driving input but not passing through the recording material through the receiving unit and a second value obtained by receiving ultrasonic waves emitted from the transmitting unit supplied with the second driving input and passing through the recording material through the receiving unit.

[0005] Other features of the invention will become clear from the following description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0006] Figure 1 This is a schematic configuration diagram of an image forming apparatus according to a first exemplary embodiment.

[0007] Figure 2 This is a control block diagram for a recording material detection apparatus according to a first exemplary embodiment.

[0008] Figure 3 It is a graph showing an approximate expression obtained by plotting the relationship between the position correction factor and the weight of the recording material.

[0009] Figure 4 This is an example of a schematic configuration diagram of a launch control unit according to a first exemplary embodiment.

[0010] Figure 5 This is an example of a schematic configuration diagram of a launch control unit according to a first exemplary embodiment.

[0011] Figure 6 This is an example of a schematic configuration diagram of a launch control unit according to a first exemplary embodiment.

[0012] Figure 7 This is an example of a schematic configuration diagram of a launch control unit according to a first exemplary embodiment.

[0013] Figure 8 This is a flowchart of a process performed by a recording material detection apparatus according to a first exemplary embodiment for calculating the detection value of the recording material's weight.

[0014] Figure 9A , Figure 9B , Figure 9C, Figure 9D , Figure 9E , Figure 9F , Figure 9G and Figure 9H This is a timing diagram showing the state of signals and voltages related to the processing performed by the recording material detection apparatus for calculating the detection value of gram weight, for example, according to a first exemplary embodiment.

[0015] Figure 10A and Figure 10B This is a diagram illustrating an example of the relationship between the output waveform, the received signal waveform, the detected signal waveform, and the signal-to-noise ratio of a transmitting circuit unit according to a first exemplary embodiment.

[0016] Figure 11 This is a control block diagram for a recording material detection apparatus according to a fourth exemplary embodiment.

[0017] Figure 12 This is a flowchart of a process performed by a recording material detection apparatus according to a fourth exemplary embodiment for calculating the detection value of the recording material's weight.

[0018] Figure 13A , Figure 13B , Figure 13C , Figure 13D , Figure 13E , Figure 13F , Figure 13G and Figure 13H This is a timing diagram showing the state of signals and voltages related to, for example, the processing performed by the recording material detection apparatus according to the fourth exemplary embodiment for calculating the detection value of weight.

[0019] Figure 14 This is a control block diagram for a recording material detection apparatus according to a modified example of a fourth exemplary embodiment.

[0020] Figure 15 This is a control block diagram for a recording material detection apparatus according to a fifth exemplary embodiment.

[0021] Figure 16 It is a graph showing an approximate expression obtained by plotting the relationship between the position correction factor and the weight of the recording material.

[0022] Figure 17A and Figure 17B This is a diagram illustrating an example of the relationship between the output waveform of the transmitting circuit unit according to the fifth exemplary embodiment, the waveform of the received signal, the waveform of the peak detection signal, the amplification of the received signal, and the signal-to-noise ratio.

[0023] Figure 18This is a flowchart of a process performed by the recording material detection apparatus according to a fifth exemplary embodiment for calculating the detection value of the recording material's weight.

[0024] Figure 19A , Figure 19B , Figure 19C , Figure 19D , Figure 19E , Figure 19F and Figure 19G This is a timing diagram showing the state of signals and voltages related to, for example, the processing performed by the recording material detection apparatus according to the fifth exemplary embodiment for calculating the detection value of weight.

[0025] Figure 20 This is a diagram illustrating an example of the relationship between the output waveform of the transmitting circuit unit according to the sixth exemplary embodiment, the waveform of the received signal, the waveform of the peak detection signal, the amplification of the received signal, and the signal-to-weight ratio.

[0026] Figure 21 This is a flowchart of a process performed by a recording material detection apparatus according to a sixth exemplary embodiment for calculating the detection value of the recording material's weight.

[0027] Figure 22A , Figure 22B , Figure 22C , Figure 22D , Figure 22E , Figure 22F and Figure 22G This is a timing diagram showing the state of signals and voltages related to, for example, the processing performed by the recording material detection apparatus according to the sixth exemplary embodiment for calculating the detection value of weight.

[0028] Figure 23 This is a schematic configuration diagram of a recording material detection apparatus according to a modified example of a sixth exemplary embodiment. Detailed Implementation

[0029] Various exemplary embodiments, features, and aspects of the present invention will now be described in detail with reference to the accompanying drawings. Furthermore, the following exemplary embodiments are not intended to limit the invention as set forth in the claims, and not all combinations of features described in the exemplary embodiments are necessarily essential to the solutions of the present invention.

[0030] Image forming equipment

[0031] Figure 1 This is a schematic configuration diagram of the image forming apparatus 1 according to a first exemplary embodiment. The image forming apparatus 1 is an electrophotographic full-color printer employing an intermediate transfer system. The image forming apparatus 1 includes four image forming stations for forming images of yellow, magenta, cyan, and yellow colors.

[0032] These four image forming stations are arranged in a line at predetermined intervals. Furthermore, in the following description, the English characters Y, M, C, and K at the end of the reference characters indicate the applicable components related to the formation of the respective toner images for yellow (Y), magenta (M), cyan (C), and black (K). In the following description, reference marks with the English characters Y, M, C, and K removed from their ends can be used when it is not necessary to distinguish between colors.

[0033] Paper tray 2 is configured to have recording material P, such as paper, stacked on it. The recording material P stacked on paper tray 2 is fed by paper feed roller 3. The recording material P fed by paper feed roller 3 is conveyed by transfer roller pair 4 and alignment roller pair 5. Alignment sensor 6 for detecting the presence or absence of recording material P is arranged near alignment roller pair 5.

[0034] The photosensitive drum 7 includes a photosensitive layer formed on a drum-shaped substrate made of aluminum, and is configured to be driven by a drive device (not shown) to... Figure 1 The direction of the arrow shown rotates at a predetermined processing speed. Furthermore, as mentioned herein, the processing speed is equivalent to the circumferential speed (surface movement speed) of the photosensitive drum 7. The charging roller 8 charges the photosensitive drum 7 to a predetermined potential in a uniform manner. The laser scanner 9 radiates a laser corresponding to the image information, thereby exposing the surface of the photosensitive drum 7 to the laser. Using this process, an electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum 7.

[0035] The processing cartridge 10 includes a developing roller 11, and the electrostatic latent image formed on the photosensitive drum 7 is developed using the developing roller 11 with toner contained in the processing cartridge 10. A primary transfer roller 12 transfers the image formed on the photosensitive drum 7 to an intermediate transfer belt 13 in one pass. The intermediate transfer belt 13 is driven by a drive roller 14.

[0036] The secondary transfer roller 15 transfers the image initially transferred to the intermediate transfer belt 13 a second time onto the recording material P. The fixing unit 16 performs heating and pressing to fix the second-transferred image onto the recording material P. The above-mentioned components related to image formation, from the photosensitive drum 7 to the fixing unit 16, are configured as an example of the image forming unit 17. The discharge roller 18 discharges the recording material P, which has been fixed by the fixing unit 16, onto the discharge tray.

[0037] The recording material detection device 19, which acts as a detection unit, detects information about the basis weight of the recording material P. The following description describes a method for identifying the type of recording material P based on its basis weight, and a method for controlling image forming conditions (secondary transfer conditions and fixing conditions) according to the determined type of recording material P. Since the resistivity of the recording material P typically varies with its basis weight, it is necessary to change the secondary transfer conditions depending on the basis weight, such as applying a secondary transfer bias voltage to the secondary transfer toner. Furthermore, since the heat capacity of the recording material P varies with its basis weight, it is necessary to change the fixing conditions depending on the basis weight, such as the fixing temperature and fixing time for the fixing toner, and the transport speed of the recording material P.

[0038] The control unit 20 includes a microprocessor unit (MPU) and a storage unit. The MPU includes, for example, a central processing unit (CPU), and the storage unit includes, for example, random access memory (RAM) and read-only memory (ROM). The RAM is used for calculation and temporary storage of data required for controlling the image forming apparatus 1, and the ROM stores programs and various data for controlling the image forming apparatus 1. The control unit 20 identifies the type of recording material P based on detection values ​​of information about the weight detected by the recording material detection device 19. Then, the control unit 20 determines the image forming conditions corresponding to the type of recording material P and executes control to operate the image forming apparatus 1 under the image forming conditions corresponding to the type of recording material P.

[0039] [Recording Material Testing Device 19]

[0040] Figure 2 This is a block diagram related to the recording material detection device 19.

[0041] The recording material detection device 19 includes an ultrasonic sensor 21 as a weight detection unit, a transmission control unit 22 and a receiving detection unit 23, and is controlled by a control unit 20.

[0042] The ultrasonic sensor 21 is a sensor that detects the weight of the recording material P by using ultrasonic waves, and includes a transmitting unit 21a that emits ultrasonic waves and a receiving unit 21b that receives ultrasonic waves. In addition, the ultrasonic sensor 21 is also referred to as an "ultrasonic transmitting device".

[0043] The control unit 20 includes a switching indicator unit 20a, a transmission indicator unit 20b, and a reception level detection unit 20c configured to control the recording material detection device 19. The switching indicator unit 20a outputs a switching signal to switch the drive voltage to be supplied to the recording material detection device 19. The transmission indicator unit 20b outputs a drive signal to instruct the transmission unit 21a to emit ultrasonic waves. At this time, the waveform of the drive signal generated by the transmission indicator unit 20b becomes as follows... Figure 9D and Figure 9E As shown, the second drive signal generated by operational amplifier 34 becomes the opposite of the first drive signal in both high and low signals. Therefore, when the first drive signal is high, the second drive signal becomes low. Furthermore, when the first drive signal is low, the second drive signal becomes high. The receiving level detection unit 20c detects the received level (voltage value) of the ultrasonic wave received by the receiving unit 21b. Furthermore, the first drive signal and the second drive signal generated when the receiving unit 21b receives ultrasonic waves that do not pass through the recording material P are also referred to as "first drive input". Furthermore, the first drive signal and the second drive signal generated when the receiving unit 21b receives ultrasonic waves that pass through the recording material P are also referred to as "second drive input".

[0044] The first exemplary embodiment is configured to pause the output of the pulse wave for a predetermined time after outputting a pulse wave as a drive signal to measure the received signal once, and then output the pulse wave again to perform the next measurement after the ultrasonic wave has attenuated. This allows the influence of reflected waves, for example, from the recording material P or its surrounding portion to be reduced, thus enabling the direct wave emitted by the transmitting unit 21a to be received by the receiving unit 21b. Such a signal is referred to as a pulse train. Furthermore, in the first exemplary embodiment, for example, with respect to a single measurement, a pulse wave with a frequency of 40 kHz is output as two pulses, and the pulse train duration is 10 milliseconds.

[0045] The transmission control unit 22 is a circuit unit that drives the transmission unit 21a according to a first drive signal, a second drive signal, and a switching signal output from the control unit 20. The transmission control unit 22 includes a transmission circuit unit 28 and a voltage conversion unit 29 (also called a "voltage supply unit"). The transmission circuit unit 28 includes a first output circuit unit 24, a second output circuit unit 25, a third output circuit unit 26, and a switching unit 27. The output terminal of the first output circuit unit 24 is connected to the USS-H terminal of the transmission unit 21a. The output terminals of the second output circuit unit 25 and the third output circuit unit 26 are both connected to the switching unit 27, and the output terminal of the switching unit 27 is connected to the USS-L terminal of the transmission unit 21a.

[0046] Furthermore, in the first exemplary embodiment, the USS-H terminal is also referred to as the first terminal, and the USS-L terminal is also referred to as the second terminal. The switching unit 27 is a switching element that performs a switching operation in response to a switching signal output from the switching indication unit 20a to output either the output of the second output circuit unit 25 or the output of the third output circuit unit 26 to the USS-L terminal of the transmitting unit 21a. Furthermore, the switching unit 27 is also referred to as the first switching unit. In the first exemplary embodiment, when the switching signal is high, a drive signal from the second output circuit unit 25 is output, and when the switching signal is low, a drive signal from the third output circuit unit 26 is output.

[0047] The transmitting unit 21a transmits ultrasonic waves at a frequency of 40 kHz based on the output of the transmitting circuit unit 28. The receiving unit 21b receives the ultrasonic waves emitted from the transmitting unit 21a and outputs a received signal corresponding to the amplitude of the received ultrasonic waves to the receiving detection unit 23. Furthermore, in the first exemplary embodiment, the frequency of the ultrasonic waves is set to 40 kHz, but it only needs to be a frequency that can be used to detect the weight characteristic value of the recording material P and can be set according to the characteristic features of the element. Furthermore, the transmitting unit 21a and the receiving unit 21b are arranged near the transmission path in a manner opposite to each other across the transmission path, so that ultrasonic waves passing through the recording material P can be received, and the recording material P is transmitted through this transmission path.

[0048] Furthermore, when the receiving unit 21b receives ultrasonic waves that do not pass through the recording material P, the maximum amplitude of the ultrasonic waves emitted by the transmitting unit 21a is also called the "first maximum amplitude," and the input of the transmitting unit 21a used to cause the transmitting unit 21a to emit ultrasonic waves with the first maximum amplitude is also called the "first drive input." Furthermore, when the receiving unit 21b receives ultrasonic waves that pass through the recording material P, the maximum amplitude of the ultrasonic waves emitted by the transmitting unit 21a is also called the "second maximum amplitude," and the input of the transmitting unit 21a used to cause the transmitting unit 21a to emit ultrasonic waves with the second maximum amplitude is also called the "second drive input."

[0049] The receiving and detection unit 23 is a circuit unit that amplifies the amplitude of the received signal obtained by the ultrasonic wave transmitted through the recording material P via the receiving unit 21b and thus performs its half-wave rectification function, such as... Figure 10AAs shown in the diagram, the detection signal generated by the receiving detection unit 23 is input to the analog-to-digital (AD) port of the control unit 20, and is thus converted from an analog signal to a digital signal by the receiving level detection unit 20c. The control unit 20 detects the waveform of the detection signal based on the digital signal obtained by the conversion performed by the receiving level detection unit 20c, and calculates its peak value (maximum value) as the received ultrasonic level. Furthermore, in the first exemplary embodiment, the calculation of the received level uses the peak value included in the detection signal output from the receiving detection unit 23, but only characteristic values ​​that can be used to determine the level of the received signal, such as the effective value or average value, need to be used. Additionally, the receiving detection unit 23 is also referred to as the "receiving detection unit".

[0050] Here, the reason why, in the first exemplary embodiment, when the receiving unit 21b receives ultrasonic waves that do not pass through the recording material P, the switching signal is set to a low signal and the voltage Vc to be supplied to the transmitting unit 21a is set to 2 volts (V).

[0051] In the first exemplary embodiment, as Figure 10A and Figure 10B As shown, the received signal received by the receiving unit 21b becomes a detection signal that undergoes half-wave rectification by the receiving detection unit 23. At this time, without adjustment of the received signal amplification by the receiving detection unit 23, the value of the detection signal that the receiving detection unit 23 can generate has an upper limit. When the detection signal has a value less than or equal to the upper limit, the peak value (maximum value) calculated based on the digital signal obtained by conversion from the analog signal by the receiving level detection unit 20c can be calculated as the ultrasonic wave's received level. However, when the amplitude of the received signal is large, the detection signal reaches a value greater than the upper limit of the detection signal that the receiving detection unit 23 can generate, and the peak value (maximum value) calculated by the receiving level detection unit 20c becomes as high as the upper limit of the detection signal that the receiving detection unit 23 can generate. Therefore, even when the receiving unit 21b receives ultrasonic waves that do not pass through the recording material P, if a voltage of 10V is supplied to the transmitting unit 21a, the amplitude of the detection signal is too large, and thus the detection signal exceeds the upper limit of the detection signal that the receiving detection unit 23 can generate. Therefore, when the receiving unit 21b receives ultrasonic waves that do not pass through the recording material P, the switching signal is set to a low signal, and thus the voltage Vc to be supplied to the transmitting unit 21a is set to 2V.

[0052] Furthermore, in the first exemplary embodiment, when the receiving unit 21b receives ultrasonic waves that do not pass through the recording material P, the voltage Vc to be supplied to the transmitting unit 21a is set to 2V, but it can be set to be greater than or equal to 2V. Additionally, as long as the value of the receiving level Va described below is less than or equal to the value of the detection signal that the receiving detection unit 23 can generate, the voltage Vc to be supplied to the transmitting unit 21a can be greater than or equal to 2V.

[0053] <Correction of positional changes between receiving unit 21b and transmitting unit 21a>

[0054] Next, the correction for positional changes between the receiving unit 21b and the transmitting unit 21a required to perform paper type identification will be described.

[0055] During the manufacturing process of the image forming apparatus 1, when the ultrasonic sensor 21 is attached to the image forming apparatus 1, the positional relationship between the receiving unit 21b and the transmitting unit 21a may change relative to the recording material P, which is the object of detection. Such positional changes may cause variations in the time it takes for the ultrasonic waves to reach the receiving unit 21b, and may also cause variations in the time it takes for the received level detected by the received level detection unit 20c to reach its peak value. Therefore, a correction coefficient is calculated as described below so that the weight can be detected using the corrected positional changes.

[0056] When the receiving unit 21b receives ultrasonic waves that do not pass through the recording material P, the received level output from the received level detection unit 20c is represented by Va. Furthermore, when the receiving unit 21b receives ultrasonic waves that pass through the recording material P, the received level output from the received level detection unit 20c is represented by Vp. The position correction coefficient T is calculated using the received level Va and the received level Vp, as shown in equation (1) below. Additionally, in the first exemplary embodiment, the received level Va is also referred to as the "first value," and the received level Vp is also referred to as the "second value."

[0057] T=Vp / Va(1)

[0058] The control unit 20 calculates the weight using a graph that approximates the relationship between the position correction factor T and the weight of the recording material P, such as... Figure 3As shown in the diagram. Then, the control unit 20 determines the paper type of the recording material P based on the calculated basis weight, determines the image forming conditions corresponding to the type of recording material P, and controls the operation of the image forming apparatus 1 according to the image forming conditions. The approximate expression used here is obtained in advance from the actual basis weight and the correction coefficient T, and is stored in the non-volatile memory of the control unit 20. Although an approximate expression is used in the first exemplary embodiment, a conversion table representing the relationship between the position correction coefficient T and the basis weight of the recording material P can be used.

[0059]

[0060] The following description describes the attenuation of ultrasonic waves transmitted through the recording material P. The amount of attenuation of ultrasonic waves transmitted through the recording material P increases proportionally to the basis weight of the recording material P. Therefore, since the attenuation of ultrasonic waves increases with the increase of the basis weight of the recording material P, the value of the received level Vp becomes smaller. When the recording material P is a thin paper with a low basis weight, the attenuation of ultrasonic waves is less than that for ordinary paper, so the value of the received level Vp becomes greater than that for ordinary paper. On the other hand, when the recording material P is a thick paper with a high basis weight, the attenuation of ultrasonic waves is greater than that for ordinary paper, so the value of the received level Vp becomes less than that for ordinary paper. Therefore, when the value of the received level Vp becomes larger, the value of the position correction coefficient T also becomes larger.

[0061] For example, control unit 20 uses Figure 3 The approximate line X shown obtains the basis weight corresponding to the value of the position correction coefficient T. If the basis weight obtained by the control unit 20 is less than a given threshold, the control unit 20 determines that the paper type of the recording material P is thin paper. Furthermore, if the basis weight obtained by the control unit 20 is greater than the given threshold, the control unit 20 determines that the paper type of the recording material P is thick paper. The given threshold, as used herein, is based on a value determined by, for example,... Figure 3 The figure shows that if the weight is less than or equal to 59 g / m³ 2 If the paper type is thin paper, and the basis weight is 60g / m², then the paper type is thin paper. 2 Up to 90g / m 2 If the paper type is plain paper, and the basis weight is greater than 90 g / m², then the paper type is plain paper. 2 If the paper type is thick, then it is thick paper. Furthermore, the method for identifying paper type is not limited to this, and the relationship between basis weight and paper type can be pre-stored in non-volatile memory, and information about the stored relationship can be used for identification.

[0062] <Operational Overview of Launch Control Unit 22>

[0063] refer to Figure 4 A brief description of the operation of the launch control unit 22. Figure 4 This is an example of a schematic configuration diagram of the launch control unit 22.

[0064] The transmit control unit 22 receives a voltage Vb supplied from a power supply unit (not shown) included in the image forming apparatus 1. The voltage conversion unit 29 is a buck converter that converts the voltage Vb supplied from the power supply unit (not shown) into a given voltage Vc. The voltage Vc obtained by the voltage conversion unit 29 is supplied to the transmit circuit unit 28. In a first exemplary embodiment, the voltage conversion unit 29 switches the voltage Vc to one of 2V and 10V according to a switching signal output from the switching indication unit 20a. When the switching signal is high, the voltage Vc becomes 10V, and when the switching signal is low, the voltage Vc becomes 2V. Furthermore, in the first exemplary embodiment, the voltage 2V obtained when the switching signal is low is also referred to as the "first drive voltage," and the voltage 10V obtained when the switching signal is high is also referred to as the "second drive voltage." Furthermore, although a buck converter is used as the voltage conversion unit 29 in the first exemplary embodiment, alternatively, a converter capable of switching between voltages required to drive the transmit circuit unit 28 can be used. For example, a boost converter with a boost voltage of 3.3V can be used. Furthermore, the voltage Vc can be appropriately set within the voltage range (also referred to as the "operable range voltage") that can be used by the transmitting unit 21a to emit ultrasonic waves. Additionally, it is desirable that the voltage Vc can switch between an upper limit voltage and a lower limit voltage within the voltage range that can be used by the transmitting unit 21a to emit ultrasonic waves. Since the operable range voltage of the transmitting unit 21a in the first exemplary embodiment is 2V to 10V, the switchable voltage Vc is set to 2V and 10V.

[0065] The transmitting circuit unit 28 includes a first output circuit unit 24, a second output circuit unit 25, and a third output circuit unit 26. The first output circuit unit 24 includes a gate drive circuit unit 30 and a half-bridge circuit unit 31. The second output circuit unit 25 includes a gate drive circuit unit 32 and a half-bridge circuit unit 33. The third output circuit unit 26 is connected to ground (also abbreviated as GND) and is configured with a circuit capable of outputting a fixed voltage of 0V.

[0066] The half-bridge circuit unit 31 includes a switching element Q1 connected to a voltage Vc and a switching element Q2 connected in series with the switching element Q1. Each of the switching elements Q1 and Q2 is configured with a metal-oxide-semiconductor field-effect transistor (MOSFET). Voltage Vc is supplied to the switching element Q1, and a voltage corresponding to ground is supplied to the switching element Q2.

[0067] Gate drive circuit unit 30 includes gate drive circuit unit 30a for driving switching element Q1 and gate drive circuit unit 30b for driving switching element Q2. Gate drive circuit unit 30a includes NPN transistor Tr1, PNP transistor Tr2, NPN transistor Tr3 and resistor R1. NPN transistor Tr3 is connected to ground, and resistor R1 is connected to power supply voltage Vb. Gate drive circuit unit 30b includes NPN transistor Tr4, PNP transistor Tr5, NPN transistor Tr6, resistor R2 and resistor R3. NPN transistor Tr6 is connected to ground, and resistor R2 is connected to power supply voltage Vb.

[0068] The first drive signal output from the emission indicator unit 20b is input to resistor R3 and NPN transistor Tr6 in the gate drive circuit unit 30b. When the first drive signal is high, since NPN transistor Tr6 is connected to ground, a voltage of 0V is input to the base terminals of NPN transistor Tr4 and PNP transistor Tr5. When a voltage of 0V is input to the base terminals of NPN transistor Tr4 and PNP transistor Tr5, a voltage of 0V is output from the connection point between the emitter terminal of NPN transistor Tr4 and the collector terminal of PNP transistor Tr5 as a drive signal for switching element Q2. Furthermore, when the first drive signal is high, for the reasons mentioned above, a voltage of 0V is input from the collector terminal of NPN transistor Tr6 to NPN transistor Tr3 in the gate drive circuit unit 30a.

[0069] When the first drive signal is low, voltage Vb is input to the base terminals of NPN transistor Tr4 and PNP transistor Tr5 via resistor R2. When voltage Vb is input to the base terminals of NPN transistor Tr4 and PNP transistor Tr5, voltage Vb is output from the connection point between the emitter terminal of NPN transistor Tr4 and the collector terminal of PNP transistor Tr5 as a drive signal for switching element Q2. Furthermore, when the first drive signal is low, for the reasons mentioned above, voltage Vb is input from the collector terminal of NPN transistor Tr6 to NPN transistor Tr3 of the gate drive circuit unit 30a.

[0070] When voltage Vb is input to NPN transistor Tr3 in gate drive circuit unit 30a, since NPN transistor Tr3 is connected to ground, a voltage of 0V is input to the base terminals of NPN transistor Tr1 and PNP transistor Tr2. When a voltage of 0V is input to the base terminals of NPN transistor Tr1 and PNP transistor Tr2, a voltage of 0V is output from the connection point between the emitter terminal of NPN transistor Tr1 and the collector terminal of PNP transistor Tr2 as a drive signal for switching element Q1.

[0071] When a 0V voltage is input to the NPN transistor Tr3 of the gate drive circuit unit 30a, a voltage Vb is input to the base terminals of both the NPN transistor Tr1 and the PNP transistor Tr2 via a resistor R1. When the voltage Vb is input to the base terminals of both the NPN transistor Tr1 and the PNP transistor Tr2, a voltage Vb is output from the connection point between the emitter terminal of the NPN transistor Tr1 and the collector terminal of the PNP transistor Tr2 as a drive signal for switching element Q1.

[0072] In this way, when the first drive signal is high, the output of gate drive circuit unit 30b becomes 0V, and the output of gate drive circuit unit 30a becomes voltage Vb. Furthermore, when the first drive signal is low, the output of gate drive circuit unit 30b becomes voltage Vb, and the output of gate drive circuit unit 30a becomes 0V. Therefore, the relationship between the outputs of gate drive circuit unit 30b and gate drive circuit unit 30a becomes reversed between the cases where the first drive signal is high and low. Therefore, when the first drive signal is high, switching element Q1 receives voltage Vb as input and thus enters the ON state, while switching element Q2 receives a voltage of 0V as input and thus enters the OFF state. Therefore, no voltage is supplied from switching element Q2, and voltage Vc is output from switching element Q1 as the output voltage of half-bridge circuit unit 31. Furthermore, when the first drive signal is low, switching element Q1 receives a voltage of 0V as input and thus enters the OFF state, while switching element Q2 receives voltage Vb as input and thus enters the ON state. Therefore, no voltage is supplied from switching element Q1, and a voltage of 0V is output from switching element Q2 as the output voltage of half-bridge circuit unit 31. In this way, according to the switching operation of switching elements Q1 and Q2, which depends on the change of the first drive signal, voltage Vc and voltage 0V are alternately input to the USS-H terminal of transmitting unit 21a as the output of half-bridge circuit unit 31.

[0073] The second output circuit unit 25 has a similar circuit configuration to the first output circuit unit 24, but the difference lies in that the second drive signal to be input to the second output circuit unit 25 is opposite to the first drive signal in terms of the relationship between high and low signals. Therefore, the operational overview of the second output circuit unit 25 is omitted from the description.

[0074] The switching unit 27 switches the circuit to be connected to the USS-L terminal of the transmitting unit 21a between the second output circuit unit 25 and the third output circuit unit 26 according to the signal output from the switching indication unit 20a. This switching causes the driving mode of the transmitting unit 21a to be switched between a half-bridge driving mode and a full-bridge driving mode. Each of the half-bridge driving mode and the full-bridge driving mode is described in the following description.

[0075] [Half-bridge drive mode]

[0076] When the switching signal is low, the USS-L terminal is connected to ground of the third output circuit unit 26. Therefore, the transmitting unit 21a is driven at 2V only through the first output circuit unit 24. Thus, when the transmitting unit 21a receives a 2V pulse train as input from the switching element Q1 of the first output circuit unit 24 via the USS-H terminal, it receives a 0V voltage as input from the third output circuit unit 26 via the USS-L terminal. In the first exemplary embodiment, this state is also referred to as the "first state". Furthermore, when the transmitting unit 21a receives a 0V voltage as input from the switching element Q2 of the first output circuit unit 24 via the USS-H terminal, it receives a 0V voltage as input from the third output circuit unit 26 via the USS-L terminal. In the first exemplary embodiment, this state is also referred to as the "second state".

[0077] In this manner, in response to receiving alternately 0V voltage and 2V pulse train waves as input from switching elements Q1 and Q2 via the USS-H terminal, the transmitting unit 21a emits ultrasonic waves. Furthermore, the bridge circuit operation mode executed when the switching signal is low is also called the "half-bridge drive mode".

[0078] [Full-bridge drive mode]

[0079] When the switching signal is high, the USS-L terminal is connected to the second output circuit unit 25.

[0080] Therefore, the transmitting unit 21a is connected to both the first output circuit unit 24 and the second output circuit unit 25, and is thus driven at 10V. Therefore, when receiving a 10V pulse train as input from the switching element Q1 via the USS-H terminal, the transmitting unit 21a receives a 0V voltage as input from the switching element Q4 via the USS-L terminal. In the first exemplary embodiment, this state is also referred to as the "third state". Furthermore, when receiving a 0V voltage as input from the switching element Q2 via the USS-H terminal, the transmitting unit 21a receives a 10V pulse train as input from the switching element Q3 via the USS-L terminal. In the first exemplary embodiment, this state is also referred to as the "fourth state". In this way, in response to alternately receiving 10V pulse trains as input via the USS-H and USS-L terminals, the transmitting unit 21a can transmit ultrasonic waves with a larger amplitude than in the half-bridge drive mode. Furthermore, the bridge circuit operation mode executed when the switching signal is a high signal is also referred to as the "full-bridge drive mode". Therefore, in the first exemplary embodiment, when the receiving unit 21b receives ultrasonic waves transmitted through the recording material P, the transmitting control unit 22 drives the transmitting unit 21a in full-bridge drive mode.

[0081] Furthermore, in the first exemplary embodiment, the method for switching from a full-bridge drive mode to a half-bridge drive mode includes switching the switching element of the switching unit 27 from the output of the second output circuit unit 25 to the output of the third output circuit unit 26. However, only a fixed voltage needs to be input to the USS-L terminal of the transmitting unit 21a. For example, as Figure 5 As shown, a switching unit 40 can be used to switch between inputting a second drive signal output from the transmission indicator unit 20b to the second output circuit unit 25 and inputting a fixed voltage (0V) corresponding to ground to the second output circuit unit 25. The switching unit 40 is also referred to as the "second switching unit". Furthermore, when the switching signal output from the switching indicator unit 20a is a high signal, the second drive signal output from the transmission indicator unit 20b is input to the second output circuit unit 25. The transmission indicator unit 20b, which outputs the second drive signal to the second output circuit unit 25, is also referred to as the "fourth output circuit unit". Furthermore, when the switching signal output from the switching indicator unit 20a is a low signal, a fixed voltage (0V) corresponding to ground is input to the second output circuit unit 25. Furthermore, the circuit connected to ground and capable of outputting 0V as a fixed voltage is also referred to as the "fifth output circuit unit". Even in this case, if the switching signal is a low signal, a voltage of 0V is input from ground to the second output circuit unit 25 regardless of the drive signal output from the transmission indicator unit 20b.

[0082] This allows the USS-L terminal to be supplied with 0V. Therefore, the transmitter unit 21a operates in half-bridge drive mode.

[0083] The following description describes the operation performed when the switching signal output from the switching indicator unit 20a is a low signal and the switching unit 40 inputs a fixed voltage (0V) corresponding to ground to the second output circuit unit 25. When the switching element Q1 of the first output circuit unit 24 receives a 2V pulse train as input via the USS-H terminal, the transmitting unit 21a receives a 0V voltage as input from the second output circuit unit 25. This state is also referred to as the "fifth state". Furthermore, when the switching element Q2 of the first output circuit unit 24 receives a 0V voltage as input via the USS-H terminal, the transmitting unit 21a also receives a 0V voltage as input from the second output circuit unit 25. This state is also referred to as the "sixth state".

[0084] The following description describes the operation performed when the switching signal output from the switching indicator unit 20a is a high signal and the switching unit 40 inputs the second drive signal from the transmission indicator unit 20b to the second output circuit unit 25. When the transmission unit 21a receives a 10V pulse train as input from the switching element Q1 of the first output circuit unit 24 via the USS-H terminal, the transmission unit 21a receives a 0V voltage as input from the switching element Q4 of the second output circuit unit 25. This state is also referred to as the "seventh state". Furthermore, when the transmission unit 21a receives a 0V voltage as input from the switching element Q2 of the first output circuit unit 24 via the USS-H terminal, the transmission unit 21a receives a 10V pulse train as input from the switching element Q3 of the second output circuit unit 25. This state is also referred to as the "eighth state".

[0085] Furthermore, it is only necessary to be able to perform switching between half-bridge drive mode and full-bridge drive mode, and to configure the type of components of the half-bridge drive circuit and the configuration of the gate drive circuit to be appropriately variable.

[0086] [Based on the switching of voltage Vc depending on the presence or absence of material P]

[0087] In the following description, refer to Figure 8 and Figure 9A , Figure 9B , Figure 9C , Figure 9D , Figure 9E , Figure 9F , Figure 9G and Figure 9H A method is described for reducing the signal-to-noise ratio of the received level Vp output from the received level detection unit 20c when the received unit 21b receives ultrasonic waves transmitted through the recording material P by controlling the voltage conversion unit 29. Figure 8 This is a flowchart for calculating the weight of the recording material P, and Figures 9A to 9H It is a timing diagram showing the state of signals and voltages, for example, related to the processing used to calculate weight.

[0088] In step S100, in response to receiving a printing instruction, the control unit 20 begins the paper feeding operation.

[0089] In step S101, as Figure 9B As shown, the switching indicator unit 20a outputs a low signal as a switching signal to the voltage conversion unit 29, thereby causing the first output circuit unit 24 to output a 2V voltage Vc via the voltage conversion unit 29. Therefore, the transmitting unit 21a is driven in half-bridge drive mode.

[0090] In step S102, the control unit 20 performs the following processing after recording the time when material P has not yet reached the ultrasonic sensor 21 after the paper feeding operation begins. Therefore, as Figure 9A As shown, the control unit 20 begins to measure the received level of the ultrasonic wave obtained when the receiving unit 21b receives the ultrasonic wave without passing through the recording material P. At this time, the transmitting circuit unit 28 drives the transmitting unit 21a in half-bridge drive mode. Therefore, as... Figure 9F As shown, a 2V voltage and a 0V voltage are alternately input from the first output circuit unit 24 to the USS-H terminal, and as... Figure 9G As shown, a voltage of 0V is input from the third output circuit unit 26 to the USS-L terminal.

[0091] In step S103, the receiving detection unit 23 generates a detection signal based on the received signal obtained by the receiving unit 21b during a predetermined time period from the measurement of the received signal level until the measurement is completed. Figure 9H As shown, the received level Va is calculated. At this time, the detection signal generated by the receiving detection unit 23 is converted by the receiving detection unit 23 into a waveform with peaks at half-wavelength intervals of 40kHz, the same frequency as the ultrasonic wave emitted from the transmitting unit 21a. Furthermore, even if the number of pulses of the first drive signal is 2, as shown... Figure 9D As shown, such as Figure 9HThe number of waveforms of the detection signal shown becomes more than 2. This is because reverberation exists in the transmitting unit 21a or the receiving unit 21b. The control unit 20 detects the second waveform of the detection signal obtained by the conversion performed by the receiving level detection unit 20c, and then calculates the peak value of the second waveform. At this time, the control unit 20 calculates the peak value of the second waveform by detecting the detection signal obtained during a given predetermined time synchronized with the first drive signal. The predetermined time used here is set by pre-calculating the relationship between the distance between the transmitting unit 21a and the receiving unit 21b and the speed of sound of the ultrasonic wave. Furthermore, in the first exemplary embodiment, the control unit 20 starts the paper feeding operation in step S100, but it can be configured to start the paper feeding operation after the receiving level Va is calculated by the receiving detection unit 23.

[0092] In step S104, the switching indicator unit 20a outputs a high signal as a switching signal to the voltage conversion unit 29, such as... Figure 9B As shown, this causes the first output circuit unit 24 to output a 10V voltage Vc via the voltage conversion unit 29, as... Figure 9C As shown in the diagram. Therefore, the launch control unit 22 drives the launch unit 21a in full-bridge drive mode.

[0093] In step S105, the control unit 20 determines whether the leading edge of the recording material P has reached the alignment sensor 6, and therefore the output of the alignment sensor 6 has changed. If it is determined that the output of the alignment sensor 6 has changed to an output indicating the detection of the recording material P ("Yes" in step S105), the control unit 20 proceeds to step S106.

[0094] In step S106, in order to detect the timing of the arrival of the leading edge of the recording material P at the ultrasonic sensor 21 after reaching the alignment sensor 6, the control unit 20 starts counting the number of steps S of the pulse motor (not shown).

[0095] In step S107, the control unit 20 determines whether the count value of step S has reached a predetermined value (100), and if it determines that the count value of step S has reached the predetermined value (100) ("yes" in step S107), the control unit 20 proceeds to step S108.

[0096] In step S108, the control unit 20 causes the transmitting circuit unit 28 to drive the ultrasonic sensor 21 and begins measuring the received signal level performed by the receiving detection unit 23 when the receiving unit 21b receives the ultrasonic waves passing through the recording material P. At this time, the transmitting circuit unit 28 drives the transmitting unit 21a in full-bridge drive mode. Therefore, as shown below, Figure 9F The 10V voltage output from the first output circuit unit 24 shown in the figure and as follows Figure 9G The 10V voltage output from the second output circuit unit 25 is shown to be alternately input to the USS-H terminal and the USS-L terminal.

[0097] In step S109, the receiving detection unit 23 performs the following processing in a manner similar to the measurement method performed when the receiving unit 21b receives ultrasonic waves that do not pass through the recording material P. Therefore, the receiving detection unit 23 performs the detection of the detection signal obtained during the time period from the start of the measurement until a predetermined time has elapsed, and calculates the received level Vp obtained when the receiving unit 21b receives ultrasonic waves that pass through the recording material P.

[0098] In step S110, the control unit 20 substitutes the received levels Va and Vp into the aforementioned equation (1) to calculate the position correction coefficient T. In step S111, the control unit 20 uses the calculated position correction coefficient T and an approximate expression pre-stored in the storage unit to calculate the basis weight of the recording material P. In step S112, the control unit 20 determines the image forming conditions based on the calculated basis weight and then ends the process. Furthermore, in the first exemplary embodiment, the control unit 20 may calculate the basis weight based on the position correction coefficient T, or it may change the image forming conditions based on the position correction coefficient T. Furthermore, in the first exemplary embodiment, the control unit 20 may identify the paper type based on the position correction coefficient T.

[0099] In the manner described above, when the receiving unit 21b receives ultrasonic waves that do not pass through the recording material P, in response to the transmitting circuit unit 28 inputting a 2V voltage to the USS-H terminal and a 0V voltage to the USS-L terminal, the transmitting unit 21a emits ultrasonic waves with the amplitude obtained when a 2V voltage is supplied. On the other hand, when the receiving unit 21b receives ultrasonic waves that pass through the recording material P, in response to the transmitting circuit unit 28 alternately inputting a 10V voltage to the USS-H and USS-L terminals, the transmitting unit 21a can emit ultrasonic waves with an amplitude equivalent to that obtained when a 20V voltage is supplied. Therefore, when the receiving unit 21b receives ultrasonic waves that pass through the recording material P, the amplification of the received ultrasonic signal can be reduced, thereby minimizing the impact of noise present in the ultrasonic wave receiving circuit on the weight detection result.

[0100] <Comparison of the method in the first exemplary embodiment with conventional methods>

[0101] In the following description, when compared with conventional methods, a countermeasure method for preventing or reducing the reduction in the accuracy of weight detection in a first exemplary embodiment is described. Figure 10A and Figure 10BThis is a diagram illustrating an example of the relationship between the output waveform of the transmitting circuit unit 28, the waveform of the received signal, the waveform of the detected signal, and the signal-to-noise ratio. Figure 10A It is a graph obtained using conventional methods, and Figure 10B This is a diagram of the first exemplary embodiment.

[0102] In conventional methods, such as Figure 10A As shown, the received signal obtained when the receiving unit 21b receives ultrasonic waves passing through the recording material P is significantly attenuated compared to the received signal obtained when the receiving unit 21b receives ultrasonic waves not passing through the recording material P. Therefore, when the receiving unit 21b receives ultrasonic waves passing through the recording material P, regardless of the paper type of the recording material P, the conventional method uses a detection signal obtained by amplifying the received signal at a predetermined amplification rate to calculate the received level Vp, thereby detecting the basis weight. In this example, the amplification rate is increased from 1x to 20x. However, at this time, when the received signal obtained when the receiving unit 21b receives ultrasonic waves passing through the recording material P is amplified, the noise signal (not shown) present in the circuit receiving the ultrasonic waves is also amplified. Therefore, the signal-to-noise ratio, which is the ratio of the noise signal to the received ultrasonic wave signal, becomes larger.

[0103] On the other hand, in the first exemplary embodiment, such as Figure 10B As shown, when the receiving unit 21b receives ultrasonic waves transmitted through the recording material P, the first exemplary embodiment is configured to increase the output voltage of the transmitting circuit unit 28 without amplifying the received signal. In this way, increasing the driving voltage to be supplied to the transmitting unit 21a enables the acquisition of a received signal with a large amplitude. Therefore, the amplification rate of the received ultrasonic signal can be set to be smaller, thus preventing or reducing an increase in the signal-to-noise ratio.

[0104] As described above, the following beneficial effects can be obtained according to the first exemplary embodiment. When the receiving unit 21b receives ultrasonic waves that do not pass through the recording material P, the control unit 20 drives the transmitting unit 21a in half-bridge drive mode using the voltage at the lower limit of the operating range voltage of the transmitting unit 21a, and causes the receiving level detection unit 20c to calculate the receiving level Va. When the receiving unit 21b receives ultrasonic waves that pass through the recording material P, the control unit 20 drives the transmitting unit 21a in full-bridge drive mode using the voltage at the upper limit of the operating range voltage of the transmitting unit 21a, and causes the receiving level detection unit 20c to calculate the receiving level Vp. The switching voltage and operating mode of the bridge circuit enable an increase in the amplitude of the ultrasonic waves emitted by the transmitting unit 21a, and also enable an increase in the amplitude of the ultrasonic waves that pass through the recording material P and reach the receiving unit 21b. Therefore, an increase in the signal-to-noise ratio of the received signal can be prevented or reduced. Therefore, the weight detection of the recording material P can be performed with higher accuracy than conventional methods.

[0105] Furthermore, the first exemplary embodiment is configured to switch the voltage to be supplied to the bridge circuit not only depending on the presence or absence of the recording material P, but also to switch the operating mode of the bridge circuit according to a switching signal output from the switching instruction unit 20a. However, the amplitude of the ultrasonic wave to be emitted toward the recording material P only needs to be able to change depending on the presence or absence of the recording material P, and for example, a method of switching either the voltage of the bridge circuit or the operating mode of the bridge circuit can be employed.

[0106] The second exemplary embodiment is configured as follows: Figure 6 The diagram does not include the third output circuit unit 26 and does not require switching from full-bridge drive mode to half-bridge drive mode. Therefore, the transmit control unit 22 can use the first output circuit unit 24 and the second output circuit unit 25 to always drive the transmit unit 21a in full-bridge drive mode.

[0107] When the switching signal is low, and the transmitting unit 21a receives a 2V pulse train as input from the switching element Q1 of the first output circuit unit 24 via the USS-H terminal, the transmitting unit 21a receives a 0V voltage as input from the switching element Q4 of the second output circuit unit 25. This state is also referred to as the "ninth state". Furthermore, when the transmitting unit 21a receives a 0V voltage as input from the switching element Q2 of the first output circuit unit 24 via the USS-H terminal, the transmitting unit 21a receives a 2V pulse train as input from the switching element Q3 of the second output circuit unit 25. This state is also referred to as the "tenth state".

[0108] Furthermore, when the switching signal is high, and the transmitting unit 21a receives a 10V pulse train as input from the switching element Q1 of the first output circuit unit 24 via the USS-H terminal, the transmitting unit 21a receives a 0V voltage as input from the switching element Q4 of the second output circuit unit 25. This state is also referred to as the "eleventh state". Furthermore, when the transmitting unit 21a receives a 0V voltage as input from the switching element Q2 of the first output circuit unit 24 via the USS-H terminal, the transmitting unit 21a receives a 10V pulse train as input from the switching element Q3 of the second output circuit unit 25. This state is also referred to as the "twelfth state".

[0109] Furthermore, although the lower limit of the amplitude of the ultrasonic wave emitted by the transmitting unit 21a is equivalent to the amplitude of the ultrasonic wave obtained when a voltage of 4V is supplied, as in the first exemplary embodiment, the transmitting unit 21a is capable of emitting ultrasonic waves with an amplitude as high as that obtained when a voltage of 20V is supplied.

[0110] As described above, although the ultrasonic wave emitted by the transmitting unit 21a in the first exemplary embodiment has an amplitude equivalent to that obtained when a voltage of 2V to 20V is supplied, the ultrasonic wave emitted by the transmitting unit 21a in the second exemplary embodiment has an amplitude equivalent to that obtained when a voltage of 4V to 20V is supplied. In this case, in the second exemplary embodiment, even if the lower limit of the amplitude of the ultrasonic wave emitted by the transmitting unit 21a increases by 2V, the value of the received level Va becomes less than or equal to the value of the detection signal that the receiving detection unit 23 can generate. In this way, while satisfying the detection accuracy related to weight, even if the lower limit of the amplitude of the ultrasonic wave emitted by the transmitting unit 21a is increased, beneficial effects similar to those in the first exemplary embodiment can be obtained. Furthermore, the second exemplary embodiment enables the transmitting unit 21a to emit ultrasonic waves with an amplitude equivalent to that obtained when a voltage of 20V is supplied, without using the switching unit 27 or the switching unit 40. Therefore, the number of components can be reduced, thereby reducing manufacturing costs.

[0111] In addition, the third exemplary embodiment is configured as follows Figure 7 The diagram does not include the second output circuit unit 25 and the third output circuit unit 26, and the first output circuit unit 24 can always drive the transmitting unit 21a in half-bridge driving mode.

[0112] When the switching signal output from the switching indicator unit 20a is a low signal, and the switching element Q1 of the first output circuit unit 24 receives a 2V pulse train as input via the USS-H terminal, the transmitting unit 21a receives a 0V voltage from ground as input. This state is also called the "thirteenth state". Furthermore, when the switching element Q2 of the first output circuit unit 24 receives a 0V voltage as input via the USS-H terminal, the transmitting unit 21a also receives a 0V voltage from ground as input. This state is also called the "fourteenth state".

[0113] Furthermore, when the switching signal output from the switching indicator unit 20a is a high signal, and when the switching element Q1 of the first output circuit unit 24 receives a 10V pulse train as input via the USS-H terminal, the transmitting unit 21a receives a 0V voltage from ground as input. This state is also referred to as the "fifteenth state". Additionally, when the switching element Q2 of the first output circuit unit 24 receives a 0V voltage as input via the USS-H terminal, the transmitting unit 21a also receives a 0V voltage from ground as input. This state is also referred to as the "sixteenth state".

[0114] In this case, the lower limit of the amplitude of the ultrasonic wave emitted by the transmitting unit 21a is equivalent to the amplitude of the ultrasonic wave obtained when a voltage of 2V is supplied, and the upper limit of the amplitude of the ultrasonic wave emitted by the transmitting unit 21a is equivalent to the amplitude of the ultrasonic wave obtained when a voltage of 10V is supplied.

[0115] As described above, although the ultrasonic wave emitted by the transmitting unit 21a in the first exemplary embodiment has an amplitude equivalent to that obtained when a voltage of 2V to 20V is supplied, in the third exemplary embodiment, the ultrasonic wave emitted by the transmitting unit 21a has an amplitude equivalent to that obtained when a voltage of 2V to 10V is supplied. In this case, even if the upper limit of the amplitude of the ultrasonic wave emitted by the transmitting unit 21a is reduced by 10V, beneficial effects similar to those in the first exemplary embodiment can be obtained while maintaining the detection accuracy related to weight. Furthermore, the third exemplary embodiment enables the transmitting unit 21a to emit ultrasonic waves with an amplitude equivalent to that obtained when a voltage of 10V is supplied, without using the second output circuit unit 25, the third output circuit unit 26, and the switching unit 27 or the switching unit 40. Therefore, the number of components can be reduced, thereby lowering manufacturing costs.

[0116] Furthermore, in the first to third exemplary embodiments, it has been described that the transmitting unit 21a transmits ultrasonic waves with a frequency of 40 kHz based on the output of the transmitting circuit unit 28, and the driving voltage supplied to the transmitting unit 21a switches depending on the presence or absence of the recording material P. However, in order to prevent or reduce the increase in the signal-to-noise ratio of the received signal, a configuration can be adopted in which the driving voltage is kept constant regardless of the presence or absence of the recording material P, and the frequency of the driving signal output from the transmitting indicator unit 20b switches depending on the presence or absence of the recording material P. For example, the frequency of the driving signal on which the amplitude of the ultrasonic wave becomes at its maximum value is assumed to be a first frequency, and the frequency of the driving signal on which the amplitude of the ultrasonic wave becomes less than the amplitude of the ultrasonic wave obtained when the driving signal has the first frequency is assumed to be a second frequency. In this case, when the receiving unit 21b receives ultrasonic waves passing through the recording material P, the transmitting indicator unit 20b outputs a pulse wave with the first frequency as a driving signal. Furthermore, when the receiving unit 21b receives ultrasonic waves that do not pass through the recording material P, the transmitting indicator unit 20b outputs a pulse wave with the second frequency as a driving signal. This allows the transmitting unit 21a to output a larger amplitude ultrasonic wave when the receiving unit 21b receives ultrasonic waves passing through the recording material P, compared to the case where the receiving unit 21b receives ultrasonic waves that do not pass through the recording material P. Therefore, it is possible to prevent or reduce the increase in signal-to-noise ratio caused by the amplification of the received signal when the receiving unit 21b receives ultrasonic waves passing through the recording material P. Consequently, it becomes possible to perform the detection of the weight of the recording material P with higher accuracy than in conventional methods.

[0117] Furthermore, a configuration can be adopted in which the driving voltage and frequency of the driving signal to be output from the transmission indicator unit 20b are kept constant, regardless of the presence or absence of the recording material P, and the duty cycle between the high and low signals in the driving signal switches depending on the presence or absence of the recording material P. This allows the transmission unit 21a to output a larger amplitude ultrasonic wave when the receiving unit 21b receives ultrasonic waves passing through the recording material P, compared to the case where the receiving unit 21b receives ultrasonic waves passing through the recording material P. Therefore, the increase in signal-to-noise ratio caused by the amplification of the received signal when the receiving unit 21b receives ultrasonic waves passing through the recording material P can be prevented or reduced.

[0118] In the first to third exemplary embodiments described above, when the amplification of the received signal is not adjusted in the receiving detection unit 23, the driving voltage supplied to the transmitting unit 21a depends on the presence or absence of the recording material P and switches accordingly. Therefore, when the receiving unit 21b receives ultrasonic waves passing through the recording material P, a larger driving signal is supplied to the transmitting unit 21a than when the receiving unit 21b receives ultrasonic waves not passing through the recording material P, thereby obtaining a received signal with a large amplitude. Therefore, when the receiving unit 21b receives ultrasonic waves passing through the recording material P, the increase in signal-to-noise ratio caused by the increased amplification of the received signal due to the attenuation of the ultrasonic waves by the recording material P is prevented or reduced. The fourth exemplary embodiment is configured to exclude the switching indication unit 20a and is configured to supply a 10V driving voltage to the transmitting unit 21a, regardless of the presence or absence of the recording material P. Then, as in the second exemplary embodiment, the transmission control unit 22 drives the transmission unit 21a in full-bridge drive mode using the first output circuit unit 24 and the second output circuit unit 25, thereby enabling the transmission of ultrasonic waves with an amplitude up to that obtained when supplied with a voltage of 20V, regardless of the presence or absence of the recording material P. Then, when the receiving unit 21b receives ultrasonic waves that do not pass through the recording material P, the receiving detection unit 23 reduces the amplitude of the received signal generated by the receiving unit 21b to obtain a receiving level that can be detected by the receiving level detection unit 20c.

[0119] [Switching of ultrasonic amplification in receiving and detecting unit 23 depending on the presence or absence of recording material P]

[0120] Figure 11 This is a control block diagram for the recording material detection apparatus 19 according to the fourth exemplary embodiment. Furthermore, in the following description, [the following text is incomplete and likely refers to a different document or model]. Figure 2 The same components shown are assigned the same reference tags, and these components are omitted from the description here.

[0121] The control unit 20 also includes a gain indicator unit 20d, which is provided to control the amplification rate to be used by the receiver detection unit 23. As mentioned above, the receiver detection unit 23 is a circuit unit that performs half-wave rectification by amplifying the amplitude of the received signal output from the receiver unit 21b. The receiver detection unit 23 switches the amplification rate of the received signal output from the receiver unit 21b according to the gain indicator signal output from the gain indicator unit 20d. In the following description, the switching of the amplification rate of the received signal output from the receiver unit 21b performed by the receiver detection unit 23 is described with reference to an inverting amplifier circuit using an operational amplifier. Furthermore, in the fourth exemplary embodiment, an inverting amplifier circuit is used, but it can be replaced by a circuit capable of amplifying the signal, such as an amplifier circuit using transistors.

[0122] The inverting amplifier circuit is a circuit in which the amplification rate to be used is determined by the ratio between the resistance value of the input section connected to the negative terminal and the resistance value of the feedback section located between the negative terminal and the output terminal. Therefore, the inverting amplifier circuit can change the amplification rate by switching the resistance value of the input section or the resistance value of the feedback section. Furthermore, in the fourth exemplary embodiment, the receiving detection unit 23 switches the amplification rate to either 1 / 10 or 1x based on the gain indication signal output from the gain indication unit 20d. The receiving detection unit 23 sets the amplification rate to 1 / 10x in response to a low gain indication signal and sets the amplification rate to 1x in response to a high gain indication signal. Furthermore, in the fourth exemplary embodiment, the received signal obtained by the receiving unit 21b without the ultrasonic waves passing through the recording material P is also called the "first received value," and the received signal obtained by the receiving unit 21b through the ultrasonic waves passing through the recording material P is also called the "second received value." Furthermore, the gain indication unit 20d is also called the "amplification rate switching indication unit," and the gain indication signal output from the gain indication unit 20d is also called the "amplification rate switching signal." Furthermore, the low signal of the gain indication signal is also called the "first amplification switching signal," the amplification set to 1 / 10 is also called the "first amplification," and the detection signal obtained by amplifying the received signal at the first amplification is also called the "first conversion value." Similarly, the high signal of the gain indication signal is also called the "second amplification switching signal," the amplification set to 1 is also called the "second amplification," and the detection signal obtained by amplifying the received signal at the second amplification is also called the "second conversion value." Furthermore, in the fourth exemplary embodiment, it is assumed that the amplification is switched to either 1 / 10 or 1, but the amplification is not limited to these values. The amplification used when the receiving unit 21b receives ultrasound waves that do not pass through the recording material P can be, for example, 1 / 20, and only needs to be an amplification that can be used to make the received signal smaller. Furthermore, the amplification used when the receiving unit 21b receives ultrasound waves that pass through the recording material P only needs to be an amplification that can meet the accuracy required for the value used for weight detection.

[0123] Next, the setting of the amplification rate performed by the receiving detection unit 23 will be described in the following description. When the receiving unit 21b receives ultrasonic waves passing through the recording material P, the amplitude of the received signal input to the receiving detection unit 23 becomes smaller. Therefore, in order to set the amplification rate to be used by the receiving detection unit 23 to 1, the gain indicator unit 20d outputs a high signal as a gain indicator signal. Furthermore, when the receiving unit 21b receives ultrasonic waves that do not pass through the recording material P, the amplitude of the received signal input to the receiving detection unit 23 becomes larger. Therefore, when the received signal is amplified and undergoes half-wave rectification through the receiving detection unit 23, it is desirable to prevent or reduce the amplitude of the received signal from exceeding the range to which it undergoes half-wave rectification through the receiving detection unit 23 (hereinafter referred to as "saturation"). Therefore, the gain indicator unit 20d outputs a low signal as a gain indicator signal to set the amplification rate to 1 / 10, as a smaller multiplication factor than when the gain indicator signal is a high signal.

[0124] As described above, in the fourth exemplary embodiment, when the receiving unit 21b receives ultrasonic waves that do not pass through the recording material P, the gain indicator unit 20d outputs a low signal, and when the receiving unit 21b receives ultrasonic waves that pass through the recording material P, the gain indicator unit 20d outputs a high signal.

[0125]

[0126] In the following description, refer to Figure 12 as well as Figure 13A , Figure 13B , Figure 13C , Figure 13D , Figure 13E , Figure 13F , Figure 13G and Figure 13H The method described is to switch the amplification of the received signal to be used by the receiving detection unit 23 by switching the gain indication signal depending on the presence or absence of the recording material P through the gain indication unit 20d. Figure 12 This is a flowchart of a process for calculating the measured weight of the recording material P according to a fourth exemplary embodiment. Figures 13A to 13H This is a timing diagram showing the states of signals and voltages related to the processing performed by the recording material detection apparatus 19 for calculating the weight detection value, for example, according to the fourth exemplary embodiment. Furthermore, with Figure 8 and Figures 9A to 9H The components shown are assigned the same reference characters, and these components are omitted from the description here. Parts assigned the same reference markers perform the same functions and operations, and these parts are also omitted from the description here.

[0127] In step S100, in response to receiving a printing instruction, the control unit 20 begins the paper feeding operation.

[0128] In step S301, as Figure 13B As shown, the gain indicator unit 20d outputs a low signal as a gain switching signal to the receiver detection unit 23. The voltage conversion unit 29 causes the first output circuit unit 24 to output a 10V voltage Vc, causing the transmitter unit 21a to drive in full-bridge drive mode. Therefore, the gain indicator unit 20d outputs a low signal as a gain indicator signal to the receiver detection unit 23, causing the receiver detection unit 23 to set the amplification of the received signal to 1 / 10.

[0129] In step S302, the control unit 20 performs the following processing after recording the time when material P has not yet reached the ultrasonic sensor 21 after the paper feeding operation begins. Therefore, as Figure 13A As shown, the control unit 20 measures the received level of the ultrasonic wave obtained when the ultrasonic wave is received by the receiving unit 21b without passing through the recording material P. At this time, the transmitting circuit unit 28 drives the transmitting unit 21a in half-bridge drive mode. Therefore, as... Figure 13F As shown, a 10V voltage and a 0V voltage are alternately input from the first output circuit unit 24 to the USS-H terminal, and as... Figure 13G As shown, a 10V voltage and a 0V voltage are alternately input from the second output circuit unit 25 to the USS-L terminal.

[0130] In step S103, the receiving detection unit 23 generates a detection signal based on the received signal obtained by the receiving unit 21b during a predetermined time period from the measurement of the received signal level until the measurement is completed. Figure 13H As shown, the received level Va is calculated. At this time, the detection signal generated by the receiving detection unit 23 is converted by the receiving detection unit 23 into a waveform with peaks at half-wavelength intervals of 40kHz, the same frequency as the ultrasonic wave emitted from the transmitting unit 21a. Furthermore, even if the number of pulses of the first drive signal is 2, as shown... Figure 13D As shown, such as Figure 13HThe number of waveforms of the detection signal shown becomes more than 2. This is because reverberation exists in the transmitting unit 21a or the receiving unit 21b. The control unit 20 detects the second waveform of the detection signal obtained by the conversion performed by the receiving level detection unit 20c, and then calculates the peak value of the second waveform. At this time, the control unit 20 calculates the peak value of the second waveform by detecting the detection signal obtained during a given predetermined time synchronized with the first drive signal. The predetermined time used here is set by pre-calculating the relationship between the distance between the transmitting unit 21a and the receiving unit 21b and the speed of sound of the ultrasonic wave. Furthermore, in the fourth exemplary embodiment, the control unit 20 starts the paper feeding operation in step S100, but it can be configured to start the paper feeding operation after the receiving level Va is calculated by the receiving detection unit 23.

[0131] In step S303, as Figure 13B As shown, the gain indicator unit 20d outputs a high signal as a gain switching signal to the receiver detection unit 23, thereby causing the receiver detection unit 23 to set the amplification of the received signal to 1.

[0132] Subsequent processing operations and Figure 8 The processing operations shown are the same, so these processing operations are omitted from the description.

[0133] As described above, the fourth exemplary embodiment is configured to exclude the switching indication unit 20a and is configured to supply a 10V drive voltage to the transmitting unit 21a, regardless of the presence or absence of the recording material P. Then, as in the second exemplary embodiment, the transmitting control unit 22 uses the first output circuit unit 24 and the second output circuit unit 25 to always drive the transmitting unit 21a in full-bridge drive mode, thereby enabling the transmission of ultrasonic waves with an amplitude up to that obtained when a voltage of 20V is supplied, regardless of the presence or absence of the recording material P. Then, when the receiving unit 21b receives ultrasonic waves that do not pass through the recording material P, the receiving detection unit 23 reduces the amplitude of the received signal generated by the receiving unit 21b, thereby obtaining a receiving level detectable by the receiving level detection unit 20c. In this way, depending on the presence or absence of the recording material P, the receiving detection unit 23 switches the amplification of the received signal, thereby adjusting the amplitude of the received signal, thereby preventing or reducing an increase in the signal-to-noise ratio of the received signal. Furthermore, in the fourth exemplary embodiment, a configuration is described that improves the signal-to-noise ratio of the received signal by optimizing the amplification to be used by the receiving detection unit 23, in addition to the operation described in the second exemplary embodiment. However, in the absence of the switching indication unit 20a, and when a 10V driving voltage is supplied to the transmitting unit 21a regardless of the presence or absence of the recording material P, such a configuration can be applied to a combination of the fourth exemplary embodiment and the first or third exemplary embodiment.

[0134] In the fourth exemplary embodiment, the following method has been described. First, in the absence of the switching indication unit 20a, the method supplies a driving voltage of 10V to the transmitting unit 21a, regardless of the presence or absence of the recording material P. Then, as in the second exemplary embodiment, the method uses the first output circuit unit 24 and the second output circuit unit 25 to always drive the transmitting unit 21a in full-bridge driving mode, thereby enabling the transmission of ultrasonic waves with an amplitude up to that obtained when a voltage of 20V is supplied, regardless of the presence or absence of the recording material P. Then, when the receiving unit 21b receives ultrasonic waves that do not pass through the recording material P, the method causes the receiving detection unit 23 to reduce the amplitude of the received signal generated by the receiving unit 21b, thereby obtaining a receiving level that can be detected by the receiving level detection unit 20c.

[0135] Similar to the fourth exemplary embodiment, the modified example of the fourth exemplary embodiment is configured to exclude the switching indicator unit 20a and is configured to supply a 10V drive voltage to the transmitting circuit unit 28, regardless of the presence or absence of the recording material P. Then, as in the second exemplary embodiment, the transmitting control unit 22 uses the first output circuit unit 24 and the second output circuit unit 25 to always drive the transmitting unit 21a in full-bridge drive mode, thus enabling the transmission of ultrasonic waves with an amplitude up to that obtained when a voltage of 20V is supplied, regardless of the presence or absence of the recording material P. Then, in the modified example of the fourth exemplary embodiment, the control unit 20 further includes a gain indicator unit 20e, and the transmitting circuit unit 28 includes a first amplification switching unit (not shown) and a second amplification switching unit (not shown). Then, when the receiving unit 21b receives ultrasonic waves that do not pass through the recording material P, the first amplification switching unit and the second amplification switching unit set the amplification of the voltage to be input to the transmitting circuit unit 28 to, for example, 1 / 5 times, so that the drive voltage to be input to the transmitting unit 21a is reduced.

[0136] [The amplification of the driving voltage in the launch control unit 22 depends on the presence or absence of the recording material P.]

[0137] Figure 14 This is a control block diagram of the recording material detection apparatus 19 according to a modified example of the fourth exemplary embodiment. Furthermore, in the following description, [the following text is incomplete and likely refers to a different document or model]. Figure 11 The components shown are assigned the same reference characters, and these components are omitted from the description here.

[0138] The control unit 20 includes a gain indicator unit 20e, which controls the amplification rate of the voltage to be input to the transmitting circuit unit 28. A first amplification rate switching unit and a second amplification rate switching unit included in the transmitting circuit unit 28 switch the amplification rate of the voltage to be input to the transmitting circuit unit 28 according to a gain indicator signal output from the gain indicator unit 20e. Furthermore, in a modified example of the fourth exemplary embodiment, the corresponding voltage values ​​obtained by the first amplification rate switching unit and the second amplification rate switching unit are assumed to be the same voltage value. Furthermore, in a modified example of the fourth exemplary embodiment, the amplification rate switching is performed using an inverting amplifier circuit using an operational amplifier, which has the same configuration as in the fourth exemplary embodiment and is therefore omitted from description. Furthermore, in a modified example of the fourth exemplary embodiment, an inverting amplifier circuit is used, but it can be replaced by a circuit capable of amplifying the signal, such as an amplifier circuit using transistors.

[0139] Next, the setting of the amplification rate performed by the first amplification rate switching unit and the second amplification rate switching unit will be described in the following description. When the receiving unit 21b receives ultrasonic waves passing through the recording material P, the amplitude of the received signal input to the receiving detection unit 23 becomes smaller. Therefore, it is desirable that the amplitude of the ultrasonic waves emitted from the transmitting unit 21a is large. Therefore, in order to set the amplification rate to 1x in the first amplification rate switching unit and the second amplification rate switching unit, the gain indicator unit 20e outputs a high signal as a gain indicator signal. Furthermore, when the receiving unit 21b receives ultrasonic waves that do not pass through the recording material P, the amplitude of the received signal input to the receiving detection unit 23 becomes larger. It is desirable that the amplitude of the ultrasonic waves emitted from the transmitting unit 21a is small. Therefore, the gain indicator unit 20e outputs a low signal as a gain indicator signal to set the amplification rate to 1 / 5x in the first amplification rate switching unit and the second amplification rate switching unit, as a smaller multiplication factor than when the gain indicator signal is high.

[0140] As described above, in a modified example of the fourth exemplary embodiment, the gain indicator unit 20e outputs a low signal when the receiving unit 21b receives ultrasound waves that do not pass through the recording material P, and outputs a high signal when the receiving unit 21b receives ultrasound waves that pass through the recording material P.

[0141] In this way, depending on the presence or absence of the recording material P, the first amplification switching unit and the second amplification switching unit switch the amplification of the voltage to be input to the transmitting circuit unit 28, thereby preventing or reducing the increase in the signal-to-noise ratio of the received signal.

[0142] Furthermore, in a modified example of the fourth exemplary embodiment, the received signal obtained by the receiving unit 21b without the ultrasonic waves passing through the recording material P is also referred to as the "first received value," and the received signal obtained by the receiving unit 21b through the ultrasonic waves passing through the recording material P is also referred to as the "second received value." Additionally, the gain indicator unit 20e is also referred to as the "amplification switching indicator unit," and the gain indicator signal output from the gain indicator unit 20e is also referred to as the "amplification switching signal." Furthermore, the low signal of the gain indicator signal is also referred to as the "first amplification switching signal," the amplification set to 1 / 5 is also referred to as the "first amplification," and the voltage obtained by converting the voltage to be input to the transmitting circuit unit 28 at the first amplification is also referred to as the "first conversion input value." Furthermore, the combination of the first amplification switching unit and the second amplification switching unit is also referred to as the "amplification switching unit." Additionally, the high signal of the gain indicator signal is also referred to as the "second amplification switching signal," the amplification set to 1 is also referred to as the "second amplification," and the voltage obtained by converting the voltage to be input to the transmitting circuit unit 28 at the second amplification is also referred to as the "second conversion input value."

[0143] As described above, according to various aspects of the present invention, controlling the voltage to be supplied to the transmitting unit 21a enables the prevention or reduction of a decrease in the detection accuracy of information related to the weight of the recording material P.

[0144] [Recording Material Testing Device 119]

[0145] Figure 15 This is a control block diagram of the recording material detection device 119 according to the fifth exemplary embodiment.

[0146] The recording material detection device 119 includes an ultrasonic sensor 121, a transmitting circuit unit 122 and a receiving detection unit 123, and is controlled by a control unit 120.

[0147] The ultrasonic sensor 121 is a sensor that detects the weight of the recording material P by using ultrasonic waves, and includes a transmitting unit 121a that emits ultrasonic waves and a receiving unit 121b that receives ultrasonic waves. In addition, the ultrasonic sensor 121 is also referred to as an "ultrasonic transmitting device".

[0148] The control unit 120 includes functions configured to control the transmission indication unit 120a, the amplification switching indication unit 120b, the reception level detection unit 120c, and the peak detection unit 120d of the recording material detection device 119. The transmission indication unit 120a outputs a drive signal to the recording material detection device 119, thereby controlling the output signal to be output from the transmission unit 121a. Furthermore, the transmission indication unit 120a switches the drive voltage to be supplied to the recording material detection device 119, thereby switching the amplitude of the output signal to be output from the transmission circuit unit 122. Additionally, the transmission indication unit 120a may include a drive input switching unit that switches the frequency or drive voltage of the drive signal depending on the presence or absence of the recording material P. However, in the fifth exemplary embodiment, it is assumed that the drive voltage is constant and independent of the presence or absence of the recording material P. In this case, the drive signal generated by the transmission indication unit 120a is a pulse train signal with pulse waves of fixed duration, and the output signal obtained by switching the amplitude of the pulse train signal to a given amplitude through the transmission circuit unit 122 causes the transmission unit 121a to emit ultrasonic waves.

[0149] The output terminal of the transmitting circuit unit 122 is connected to the USS terminal of the transmitting unit 121a. The transmitting unit 121a transmits ultrasonic waves at a frequency of 40 kHz according to the output of the transmitting circuit unit 122. The receiving unit 121b receives the ultrasonic waves emitted from the transmitting unit 121a and outputs a received signal corresponding to the amplitude of the received ultrasonic waves to the receiving detection unit 123. Furthermore, in the fifth exemplary embodiment, the frequency of the ultrasonic waves is set to 40 kHz, but it only needs to be a frequency that can be used to detect the characteristic value of the weight of the recording material P and can be set according to the characteristic features of the element. In addition, the transmitting unit 121a and the receiving unit 121b are arranged near the transmission path in a manner opposite to each other across the transmission path so that the ultrasonic waves passing through the recording material P can be received, and the recording material P is transmitted through the transmission path.

[0150] Furthermore, when the receiving unit 121b receives ultrasonic waves that do not pass through the recording material P, the maximum amplitude of the ultrasonic waves emitted by the transmitting unit 121a is also referred to as the "first maximum amplitude". Furthermore, the driving voltage and driving signal used to cause the transmitting circuit unit 122 to output a first output signal to the transmitting unit 121a to emit ultrasonic waves with the first maximum amplitude are also referred to as the "first driving input". Furthermore, when the receiving unit 121b receives ultrasonic waves that pass through the recording material P, the maximum amplitude of the ultrasonic waves emitted by the transmitting unit 121a is also referred to as the "second maximum amplitude". Furthermore, the driving voltage and driving signal used to cause the transmitting circuit unit 122 to output a second output signal to the transmitting unit 121a to emit ultrasonic waves with the second maximum amplitude are also referred to as the "second driving input".

[0151] The receiving detection unit 123 is a circuit unit that amplifies the amplitude of the received signal obtained by the receiving unit 121b through the ultrasonic waves transmitted through the recording material P in response to the amplification switching indication unit 120b, and thus performs half-wave rectification. Furthermore, in the fifth exemplary embodiment, the receiving detection unit 123 is also referred to as the "receiving detection unit". The amplification switching indication unit 120b switches the amplification rate of the received signal amplitude depending on the presence or absence of the recording material P. For example, when the receiving unit 121b receives ultrasonic waves that do not transmit through the recording material P, the amplification switching indication unit 120b sets the amplification rate to 1, so the detection signal is input to the receiving level detection unit 120c without amplification. Furthermore, when the receiving unit 121b receives ultrasonic waves transmitted through the recording material P, the amplification switching indication unit 120b sets the amplification rate to a preset amplification rate for the received signal, thereby inputting the amplified detection signal to the receiving level detection unit 120c.

[0152] The detection signal generated by the receiving detection unit 123 is input to the analog-to-digital (AD) port of the control unit 120, and is thus converted from an analog signal to a digital signal by the receiving level detection unit 120c. The control unit 120 detects the waveform of the detection signal based on the digital signal obtained by the conversion performed by the receiving level detection unit 120c, and calculates its peak value (maximum value) as the received level of the ultrasonic wave. Furthermore, the peak detection unit 120d detects the waveform of the detection signal based on the digital signal obtained by the conversion performed by the receiving level detection unit 120c, and selects a waveform for detecting the peak value. In the fifth exemplary embodiment, when the receiving unit 121b receives ultrasonic waves that do not pass through the recording material P, the peak detection unit 120d selects the first wave of the detection signal as the waveform for detecting the peak value as the peak value of the peak detection signal. Furthermore, when the receiving unit 121b receives ultrasonic waves that pass through the recording material P, the peak detection unit 120d selects the waveform obtained after a predetermined time following the input drive signal as the waveform for detecting the peak value as the peak value of the peak detection signal.

[0153] Furthermore, although in the fifth exemplary embodiment, when the receiving unit 121b receives ultrasonic waves that do not pass through the recording material P, the peak detection unit 120d is configured to select the first wave of the detection signal as the waveform for detecting the peak value of the peak detection signal, the peak detection unit 120d does not necessarily need to select the first wave. When the receiving unit 121b receives ultrasonic waves that do not pass through the recording material P, the waveform selected for detecting the peak value of the peak detection signal can be any wave, as long as it is a wave whose received signal level is not saturated and can be used to detect the peak value. Furthermore, received signal level saturation refers to the detection signal obtained and output by the receiving detection unit 123 when it detects that the input received signal has reached the upper limit of the detectable detection signal.

[0154] At this time, the value of the detection signal that acts as the upper limit is also called the "first value". The first value is the maximum value of the amplitude of the wave output from the receiving detection unit 123, and the receiving detection unit 123 outputs a detection signal of a wave with an amplitude lower than or equal to the first value. Furthermore, in the fifth exemplary embodiment, when the receiving unit 121b receives ultrasonic waves passing through the recording material P, the peak detection unit 120d is configured to select the waveform obtained after a predetermined time following the input drive signal as the waveform used to detect the peak value as the peak value of the peak detection signal. However, the peak detection unit 120d does not necessarily need to select the waveform obtained after the predetermined time. Furthermore, in the fifth exemplary embodiment, the peak value obtained when the receiving unit 121b receives ultrasonic waves passing through the recording material P only needs to be set to be greater than the peak value obtained when the receiving unit 121b receives ultrasonic waves not passing through the recording material P, and the method used for such setting is not limited. Furthermore, the predetermined time used here is assumed to be a time calculated based on the relationship between the distance between the transmitting unit 121a and the receiving unit 121b measured in advance during the manufacturing process and the speed of sound of the ultrasonic waves detected in advance by the ultrasonic sensor during the manufacturing process. Furthermore, in the fifth exemplary embodiment, the calculation of the received level uses the peak value included in the detection signal output from the receiving detection unit 123, but only characteristic values ​​that can be used to determine the level of the received signal, such as the effective value or the average value, are required. Additionally, the receiving detection unit 123 is also referred to as the "receiving detection unit".

[0155] Furthermore, in the fifth exemplary embodiment, the received level obtained when the receiving unit 121b receives ultrasound waves that do not pass through the recording material P is represented by Val, and the received level obtained when the receiving unit 121b receives ultrasound waves that pass through the recording material P is represented by Vp3. Furthermore, the control unit 120 uses the received levels Va1 and Vp3 to perform the calculation of the weight of the recording material P.

[0156] <Correction of positional changes between receiving unit 121b and transmitting unit 121a>

[0157] Next, the correction for positional changes between the receiving unit 121b and the transmitting unit 121a required to perform paper type identification will be described.

[0158] During the manufacturing process of the image forming apparatus 1, when the ultrasonic sensor 121 is attached to the image forming apparatus 1, the positional relationship between the receiving unit 121b and the transmitting unit 121a may change relative to the recording material P, which is the object of detection. Such a positional change may cause a change in the time it takes for the ultrasonic wave to reach the receiving unit 121b, and may also cause a change in the time it takes for the received level detected by the received level detection unit 120c to reach its peak value. Therefore, a correction coefficient is calculated as described below so that the weight can be detected using the corrected positional change.

[0159] When the receiving unit 121b receives ultrasonic waves that do not pass through the recording material P, the received level output from the receiving level detection unit 120c is represented by Va1. Furthermore, when the receiving unit 121b receives ultrasonic waves that pass through the recording material P, the received level output from the receiving level detection unit 120c is represented by Vp3. The position correction coefficient T is calculated using the received level Va1 and the received level Vp3, as shown in equation (2) below. Furthermore, in the fifth exemplary embodiment, the received level Va1 is also referred to as "amplitude information about the first wave," and the received level Vp3 is also referred to as "amplitude information about the second wave."

[0160] T = Vp3 / Va1(2)

[0161] The control unit 120 calculates the weight using a graph that approximates the relationship between the position correction factor T and the weight of the recording material P, such as... Figure 16 As shown in the diagram. Then, the control unit 120 determines the paper type of the recording material P based on the calculated basis weight, determines the image forming conditions corresponding to the type of recording material P, and controls the operation of the image forming apparatus 1 according to the image forming conditions. The approximate expression used here is obtained in advance from the actual basis weight and the correction coefficient T, and is stored in the non-volatile memory of the control unit 20. Although an approximate expression is used in the fifth exemplary embodiment, a conversion table representing the relationship between the position correction coefficient T and the basis weight of the recording material P can be used.

[0162]

[0163] The following description describes the attenuation of ultrasonic waves transmitted through the recording material P. The attenuation of ultrasonic waves transmitted through the recording material P increases proportionally to the basis weight of the recording material P. Therefore, since the attenuation of ultrasonic waves increases with the increase of the basis weight of the recording material P, the value of the received level Vp3 becomes smaller. When the recording material P is a thin paper with a low basis weight, the attenuation of ultrasonic waves is less than that for ordinary paper, so the value of the received level Vp3 becomes greater than that for ordinary paper. On the other hand, when the recording material P is a thick paper with a high basis weight, the attenuation of ultrasonic waves is greater than that for ordinary paper, so the value of the received level Vp3 becomes less than that for ordinary paper. Therefore, when the value of the received level Vp3 becomes larger, the value of the position correction coefficient T also becomes larger.

[0164] For example, control unit 120 uses Figure 16 The approximate line X shown obtains the basis weight corresponding to the value of the position correction coefficient T. If the basis weight obtained by the control unit 120 is less than a given threshold, the control unit 120 determines that the paper type of the recording material P is thin paper. Furthermore, if the basis weight obtained by the control unit 120 is greater than the given threshold, the control unit 120 determines that the paper type of the recording material P is thick paper. The given threshold, as used herein, is based on a value determined by, for example,... Figure 16 The figure shown is for a weight less than or equal to 59 g / m³. 2 If the paper type is thin paper, and the basis weight is 60g / m², then the paper type is thin paper. 2 Up to 90g / m 2 If the paper type is plain paper, and the basis weight is greater than 90 g / m², then the paper type is plain paper. 2 If the paper type is thick, then it is thick paper. Furthermore, the method for identifying paper type is not limited to this, and the relationship between basis weight and paper type can be pre-stored in non-volatile memory, and information about the stored relationship can be used for identification.

[0165] <The reason why the waveform that can be used to detect peaks depends on the presence or absence of the recording material P>

[0166] Next, in the fifth exemplary embodiment, the reason for switching the waveform that can be used to detect the peak depends on the presence or absence of the recording material P is described.

[0167] First, refer to Figure 17A This describes the detection of the peak value of the waveform obtained at the same timing between the case where the receiving unit 121b receives ultrasonic waves that do not pass through the recording material P and the case where the receiving unit 121b receives ultrasonic waves that pass through the recording material P. Figure 17AIn the example shown, in each of the cases where the receiving unit 121b receives ultrasonic waves that do not pass through the recording material P and the cases where the receiving unit 121b receives ultrasonic waves that pass through the recording material P, the peak detection unit 120d selects the peak value of the third waveform of each of the corresponding received signals as the peak detection signal.

[0168] The switching of the amplification rate of the receiving detection unit 123 and the signal-to-noise ratio obtained as a result of the amplification rate switching are described.

[0169] When the receiving unit 121b receives ultrasonic waves that do not pass through the recording material P, the control unit 120 determines the amplitude of the output voltage in a manner that the received signal level Va3 will not become saturated. Figure 17A As shown in the fifth exemplary embodiment. In this embodiment, the amplification rate is set to 1x. Furthermore, in the fifth exemplary embodiment, the amplification rate set to 1x is also referred to as the "first amplification rate". Since the ultrasonic wave is attenuated by the recording material P when the receiving unit 121b receives the ultrasonic wave, the received signal becomes smaller and the detected signal also becomes smaller. Therefore, as... Figure 17A As shown, the control unit 120 determines the amplification rate in such a way that the amplification rate of the received signal is greater than the amplification rate set for the receiving unit 121b to receive ultrasonic waves that do not pass through the recording material P, and the received signal level Vp3 does not become saturated. In the fifth exemplary embodiment, the amplification rate to be used at this time is set to 20 times. Furthermore, in the fifth exemplary embodiment, the amplification rate set to 20 times is also referred to as the "third amplification rate". However, at this time, when the received signal obtained when the receiving unit 121b receives ultrasonic waves passing through the recording material P is amplified, noise signals (not shown) present in the circuit for receiving ultrasonic waves may also be amplified. Therefore, the signal-to-noise ratio, which is the ratio of the noise signal to the received ultrasonic wave signal, becomes larger.

[0170] Therefore, in the fifth exemplary embodiment, the peak detection unit 120d detects the peak value of the waveform obtained at different timing points between the case where the receiving unit 121b receives ultrasonic waves that do not pass through the recording material P and the case where the receiving unit 121b receives ultrasonic waves that pass through the recording material P. In the following description, reference is made to... Figure 17B The switching of the peak detection waveform is described in the fifth exemplary embodiment.

[0171] exist Figure 17B In the example shown, when the receiving unit 121b receives ultrasonic waves that do not pass through the recording material P, for example, the peak detection unit 120d selects the peak value of the unsaturated first waveform of the received signal as the peak detection signal.

[0172] Furthermore, when the receiving unit 121b receives ultrasonic waves transmitted through the recording material P, for example, the peak detection unit 120d selects the peak value of the third waveform of the received signal as the peak detection signal. The switching of the amplification rate of the receiving detection unit 123 and the signal-to-noise ratio obtained as a result of the amplification rate switching are described.

[0173] When the receiving unit 121b receives ultrasonic waves that do not pass through the recording material P, the control unit 120 determines the amplitude of the output signal in such a way that the received level Va1 of the detection signal does not become saturated. In the fifth exemplary embodiment, when the receiving unit 121b receives ultrasonic waves that do not pass through the recording material P, the control unit 120 makes the amplitude of the output signal so large that it corresponds to a level where the received level Va1 of the first waveform of the received signal does not become saturated. In the fifth exemplary embodiment, the control unit 120 sets the drive voltage to 10V and sets the amplification of the received signal to 1x. Furthermore, in the fifth exemplary embodiment, the amplification set to 1x is also referred to as the "first amplification". Furthermore, in the fifth exemplary embodiment, it is assumed that the received level of the first waveform of the received signal is a received level that is less than the received level of the third waveform, such as... Figure 17A The receiving unit 121b shown receives the waveform of the peak detection signal in the case where the ultrasonic wave does not pass through the recording material P. However, the magnitude relationship between the received levels does not necessarily need to be this relationship.

[0174] Next, when the receiving unit 121b receives ultrasonic waves passing through the recording material P, the control unit 120 determines the amplification of the received signal when the receiving unit 121b receives ultrasonic waves passing through the recording material P in such a way that the received signal level Vp3 does not become saturated. At this time, the control unit 120 changes the waveform of the peak value of the received level detected when the receiving unit 121b receives ultrasonic waves not passing through the recording material P to a third waveform. The control unit 120 sets the amplitude of the output signal to a level large enough that the received level Va1 does not become saturated and is independent of the presence or absence of the recording material P. In the fifth exemplary embodiment, the control unit 120 sets the drive voltage to 10V. Therefore, the amplification of the received signal when the receiving unit 121b receives ultrasonic waves passing through the recording material P can be set to 10 times, which is less than Figure 17A The magnification factor shown is [number]. Furthermore, in the fifth exemplary embodiment, the magnification factor set to 10x is also referred to as the "second magnification factor." In this way, [the following is unclear and likely incomplete:] Figure 17B In the case shown, since the amplification of the received signal can be set to be less than that in Figure 17A The amplification ratio shown in the example can therefore prevent or reduce the signal-to-noise ratio from becoming greater than [value missing]. Figure 17A The signal-to-noise ratio is shown in the example.

[0175] Furthermore, the amplitude of the output signal is not limited to the voltage value described in the fifth exemplary embodiment, as long as it is within a range where the peak detection signal Va1 will not become saturated. Furthermore, the amplification of the received signal is not limited to the amplification described in the fifth exemplary embodiment, as long as it is within a range where the peak detection signal Vp3 will not become saturated.

[0176] [The switching of peak detection signals depends on the presence or absence of the recording material P]

[0177] In the following description, refer to Figure 18 as well as Figure 19A , Figure 19B , Figure 19C , Figure 19D , Figure 19E , Figure 19F and Figure 19G The method described describes a method by which the peak detection unit 120d switches the peak detection signal depending on the presence or absence of the recording material P to prevent or reduce the increase in signal-to-noise ratio when the receiving unit 121b receives ultrasonic waves passing through the recording material P. Figure 18 This is a flowchart for calculating the weight of the recording material P, and Figures 19A to 19G It is a timing diagram showing the state of signals and voltages, for example, related to the processing used to calculate weight.

[0178] In step S1100, in response to receiving a print instruction, the control unit 120 begins the paper feeding operation.

[0179] In step S1101, the control unit 120 outputs a low signal as a switching signal for the peak detection signal to be output by the peak detection unit 120d, such as... Figure 19B As shown in the image.

[0180] In step S1102, the transmission indication unit 120a included in the control unit 120 sets the driving voltage to be output by the transmission circuit unit 122 to 10V, such as Figure 19D As shown in the diagram. Therefore, the amplification switching indication unit 120b sets the amplification of the received signal from the receiving detection unit 123 to 1x, as shown in the diagram. Figure 19C As shown in the image.

[0181] In step S1103, the control unit 120 performs the following processing after recording the timing when material P has not yet reached the ultrasonic sensor 121 after the paper feeding operation begins. Therefore, as Figure 19AAs shown, the control unit 120 begins to measure the received level of the ultrasonic wave obtained when the receiving unit 121b receives the ultrasonic wave without passing through the recording material P. The control unit 120 outputs a high signal from the transmission indication unit 120a to the transmission circuit unit 122 as a drive signal, as shown. Figure 19E As shown in the diagram. In response to the drive signal output from the transmission indicator unit 120a, the transmission circuit unit 122 inputs a 10V voltage as an output signal to the USS terminal of the transmission unit 121a, as shown in the diagram. Figure 19F As shown in the diagram. At this time, a pulse train signal with a pulse wave voltage of 10V is input from the transmitting circuit unit 122 to the USS terminal. Furthermore, in the fifth exemplary embodiment, regarding the driving signal, for example, the frequency is set to 40kHz, the number of pulses is set to 2, and the duration of the pulse train signal is set to 10 milliseconds.

[0182] In step S1104, the control unit 120 detects the first waveform Va1 of the detection signal and detects its peak value. The detection of the peak value of the first waveform Va1 is described below.

[0183] The receiving detection unit 123 receives the received signal output from the receiving unit 121b after the drive signal is input to the transmitting unit 121a as input. Then, the receiving detection unit 123 begins detecting the received signal as a detection signal after a predetermined time T1 synchronized with the drive signal. More specifically, after the predetermined time T1 synchronized with the drive signal, when the detection signal exceeds a reference value (e.g., set to 0V), the receiving detection unit 123 begins detecting the detection signal and continues detecting the detection signal until the detection signal returns to the reference value. In the fifth exemplary embodiment, it is assumed that the predetermined time T1 is a time calculated based on the relationship between the distance between the transmitting unit 121a and the receiving unit 121b, pre-measured during the manufacturing process, and the speed of sound of the ultrasonic wave pre-detected by the ultrasonic sensor during the manufacturing process. Furthermore, the predetermined time T1 is also referred to as the "first time," and the time from when the control unit 120 begins detecting the detection signal until the detection signal returns to the reference value is also referred to as the "second time." Furthermore, assuming that the period from the first time to the second time is the period during which a wave with an amplitude lower than a first value is output, where the first value is the maximum amplitude of the wave that the receiving detection unit 123 can output. In this way, the control unit 120 performs detection of the detection signal during the period from when the drive input is input to the transmitting unit 121a for a predetermined time T1 until the second time has elapsed, thereby calculating the received level Va1. Furthermore, in the fifth exemplary embodiment, the first waveform Va1 is also referred to as the "first wave," and the value related to the amplitude that serves as the received level Va1 is also referred to as "amplitude information about the first wave." At this time, based on the received ultrasonic wave signal received by the receiving unit 121b, the detection signal generated by the receiving detection unit 123 has a waveform with peaks at half-wavelength intervals of 40 kHz, the same frequency as the frequency of the sound wave emitted from the transmitting unit 121a. Furthermore, even if the number of pulses of the drive signal is two, the number of waveforms of the received signal is more than two. This is because reverberation exists in the transmitting unit 121a or the receiving unit 121b.

[0184] In step S1105, the control unit 120 outputs a high signal as a switching signal for the peak detection signal to be output by the peak detection unit 120d, such as... Figure 19B As shown in the image.

[0185] In step S1106, the transmission indication unit 120a included in the control unit 120 sets the driving voltage to be output by the transmission circuit unit 122 to 10V, such as Figure 19D As shown in the diagram. Therefore, the amplification switching indication unit 120b sets the amplification of the received signal from the receiving detection unit 123 to 10 times, as shown in the diagram. Figure 19C As shown in the image.

[0186] In step S1107, the control unit 120 performs the following processing based on whether the leading edge of the recording material P has reached the alignment sensor 6. If it is determined that the leading edge of the recording material P has reached the alignment sensor 6 ("yes" in step S1107), the control unit 120 advances the processing to step S1108.

[0187] In step S1108, in order to detect the timing of the arrival of the leading edge of the recording material P at the ultrasonic sensor 121 after reaching the alignment sensor 6, the control unit 120 starts counting the number of steps S of the pulse motor (not shown).

[0188] In step S1109, the control unit 120 advances the process to step S1110 based on whether the count value of step number S has reached a predetermined value (100). If it is determined that the count value of step number S has reached the predetermined value (100) ("Yes" in step S1109), the control unit 120 advances the process to step S1110.

[0189] In step S1110, the control unit 120 outputs a high signal from the transmission indication unit 120a to the transmission circuit unit 122 as a drive signal, such as... Figure 19E As shown in the figure. The control unit 120 causes the transmitting circuit unit 122 to output an output signal to drive the ultrasonic sensor 121, and begins to measure the received signal level performed by the receiving detection unit 123 when the receiving unit 121b receives the ultrasonic waves passing through the recording material P.

[0190] The transmitting circuit unit 122 inputs a 10V voltage to the USS terminal according to the drive signal output from the transmitting indicator unit 120a, such as... Figure 19F As shown in the image.

[0191] In step S1111, the control unit 120 detects the third waveform Vp3 of the detection signal and detects its peak value. The detection of the peak value of the third waveform Vp3 is described below.

[0192] The receiving detection unit 123 receives the received signal output from the receiving unit 121b after the drive signal is input to the transmitting unit 121a as input. Then, similar to the detection of the detection waveform Va1 obtained when the receiving unit 121b receives ultrasound waves that do not pass through the recording material P, the receiving detection unit 123 begins to detect the received signal as a detection signal after a predetermined time T2 synchronized with the drive signal. More specifically, after the predetermined time T2 synchronized with the drive signal, when the detection signal exceeds a reference value (e.g., set to 0V), the receiving detection unit 123 begins to detect the detection signal and continues to detect the detection signal until the detection signal returns to the reference value. In the fifth exemplary embodiment, the predetermined time T2 is assumed to be a time calculated based on the relationship between the distance between the transmitting unit 121a and the receiving unit 121b measured in advance during the manufacturing process and the speed of sound of the ultrasound waves detected in advance by the ultrasonic sensor during the manufacturing process, and is assumed to be longer than the predetermined time T1.

[0193] Furthermore, the predetermined time T2 is also referred to as the "third time," and the time from when the control unit 120 starts detecting the detection signal until the detection signal returns to the reference value is also referred to as the "fourth time." Furthermore, it is assumed that the period from the third time to the fourth time is the period during which a wave with an amplitude lower than a first value is output, where the first value is the maximum amplitude of the wave that the receiving detection unit 123 can output. In this way, the control unit 120 performs detection of the detection signal during the period from when the drive input is input to the transmitting unit 121a for the predetermined time T2 until the fourth time has elapsed, thereby calculating the received level Vp3. Furthermore, in the fifth exemplary embodiment, the third waveform Vp3 is also referred to as the "second wave," and the value related to the amplitude that serves as the received level Vp3 is also referred to as "amplitude information about the second wave."

[0194] In step S1112, the control unit 120 substitutes the received levels Va1 and Vp3 into the aforementioned equation (2) to calculate the position correction coefficient T. In step S1113, the control unit 120 uses the calculated position correction coefficient T and the approximate expression pre-stored in the storage unit to calculate the basis weight of the recording material P. In step S1114, the control unit 120 determines the image forming conditions based on the calculated basis weight and then ends the process. Furthermore, in the fifth exemplary embodiment, the control unit 120 may calculate the basis weight based on the position correction coefficient T, or may change the image forming conditions based on the position correction coefficient T. Furthermore, in the fifth exemplary embodiment, the control unit 120 may identify the paper type based on the position correction coefficient T.

[0195] Furthermore, in the fifth exemplary embodiment, the driving voltage used to change the amplitude of the output signal to be output from the transmitting circuit unit 122 is set to 10V. However, the driving voltage is not limited to 10V, but can be a voltage higher than 10V, as long as it can detect a value that will not become saturated when the receiving unit 121b receives ultrasonic waves that do not pass through the recording material P as the receiving level of the detection signal.

[0196] In this manner, in the fifth exemplary embodiment, the peak detection unit 120d switches the waveform used to detect the peak of the received signal depending on the presence or absence of the recording material P. Therefore, when the receiving unit 121b receives ultrasound waves that do not pass through the recording material P, for example, the peak detection unit 120d selects the peak of the first waveform of the received signal as the peak detection signal. Furthermore, when the receiving unit 121b receives ultrasound waves that pass through the recording material P, for example, the peak detection unit 120d selects the peak of the third waveform of the received signal as the peak detection signal. Therefore, when the receiving unit 121b receives ultrasound waves that pass through the recording material P, the amplification of the received ultrasound signal can be prevented or reduced, thereby reducing the influence of noise present in the circuit receiving the ultrasound waves on the weight detection result.

[0197] Furthermore, in the fifth exemplary embodiment, a method for detecting a detection signal obtained at a predetermined time synchronized with a drive signal is described as a method for switching the waveform used to detect the peak value of the received signal depending on the presence or absence of the recording material P, with the peak detection unit 120d switching the waveform used to detect the peak value. However, the method for switching the waveform used to detect the peak value is not limited to this. For example, the method for switching the waveform used to detect the peak value may include a method in which the receive level detection unit 120c uses a digital signal obtained by converting the detection signal generated by the receive detection unit 123 to detect the waveform of the detection signal, thereby counting the waveform. At this time, the receive level detection unit 120c may count the points where the digital signal of the detection signal becomes the maximum value and the waveform reaches the peak value, or it may count the points where the digital signal of the detection signal becomes 0 and the waveform intersects the horizontal axis.

[0198] Furthermore, in the fifth exemplary embodiment, the method for switching the waveform used to detect the peak value may include the following methods. For example, the method may include pre-detecting the detection signal using an ultrasonic sensor during the manufacturing process, setting a threshold Vth to a value at which the received level of the detection signal will not become saturated, and detecting the time from when the drive input is input to the transmitting unit 121a until the detection signal exceeds the threshold Vth. In this case, the threshold Vth is set to a value at which the received level of the detection signal will not become saturated, that is, a value less than the upper limit of the signal that can be used to detect the received signal by the receiving detection unit 123. Furthermore, the threshold Vth is also referred to as a "second value". When the receiving unit 121b receives ultrasonic waves that do not pass through the recording material P, the time from when the drive input is input to the transmitting unit 121a until the detection signal becomes greater than or equal to the threshold Vth value is represented by Ta. Furthermore, when the receiving unit 121b receives ultrasonic waves that pass through the recording material P, the time from when the drive input is input to the transmitting unit 121a until the detection signal becomes greater than or equal to the threshold Vth value is represented by Tp. A method for detecting the weight of the recording material P based on the times Ta and Tp thus obtained may also be employed. In addition, time Ta is also called the "first period", and time Tp is also called the "second period".

[0199] In the fifth exemplary embodiment, a method is described as a way to prevent or reduce the amplification of the received ultrasonic signal. The described method includes keeping the driving voltage used to switch the amplitude of the output signal to be output from the transmitting circuit unit 122 constant, for example, 10V, regardless of the presence or absence of the recording material P, and switching the waveform used for detecting peaks depending on the presence or absence of the recording material P. In the sixth exemplary embodiment, a method is described for switching the magnitude of the output signal and switching the waveform used for detecting peaks depending on the presence or absence of the recording material P. Furthermore, components identical to those in the fifth exemplary embodiment are assigned corresponding identical reference characters and are omitted from the description here. It is also assumed that portions assigned the same reference marks perform corresponding identical functions and operations.

[0200] First, when the receiving unit 121b receives ultrasonic waves passing through the recording material P, this method results in a larger amplitude output signal, thereby preventing or reducing an increase in the amplification of the received signal. This can prevent or reduce an increase in the signal-to-noise ratio of the received level Vp3 of the detection signal obtained when the receiving unit 121b receives ultrasonic waves passing through the recording material P. In the following description, reference is made to... Figure 20 The switching of the peak detection waveform in the sixth exemplary embodiment is described.

[0201] exist Figure 20 In the example shown, with Figure 17BAs in the example shown, when the receiving unit 121b receives ultrasonic waves that do not pass through the recording material P, for example, the method selects the peak value of the first waveform of the received signal as the peak detection signal. Furthermore, when the receiving unit 121b receives ultrasonic waves that pass through the recording material P, for example, the method selects the peak value of the third waveform of the received signal as the peak detection signal. The switching of the amplification of the receiving detection unit 123 and the signal-to-noise ratio obtained as a result of the amplification switching are described.

[0202] Figure 20 The description of the receiving unit 121b shown receiving ultrasonic waves that do not pass through the recording material P is consistent with... Figure 17B The examples shown are similar, so they are omitted from the description.

[0203] exist Figure 20 When the receiving unit 121b receives ultrasonic waves transmitted through the recording material P, the method determines the amplitude and amplification of the output signal in a manner that ensures the received signal level Vp3 does not saturate. In the sixth exemplary embodiment, the method switches the driving voltage based on the presence or absence of the recording material P by driving the input switching unit, and sets the driving voltage to, for example, 20V for the case where the receiving unit 121b receives ultrasonic waves transmitted through the recording material P. Figure 17B Compared to the example shown, this allows for a magnification reduction of up to 5x. Compared to Figure 17B Compared to the example shown, since the amplification can be set to be smaller, it is possible to prevent or reduce the increase in signal-to-noise ratio.

[0204] Furthermore, the amplitude of the output signal is not limited to the voltage value described in the sixth exemplary embodiment, as long as it is within a range where the peak detection signal Va1 will not become saturated. Furthermore, the amplification of the received signal is not limited to the amplification described in the sixth exemplary embodiment, as long as it is within a range where the peak detection signal Vp3 will not become saturated.

[0205] [Switching of output signal and peak detection signal depending on the presence or absence of recording material P>

[0206] The following description describes a method by which the peak detection unit 120d switches the peak detection signal depending on the presence or absence of the recording material P to prevent or reduce the increase in the signal-to-noise ratio of the received level Vp when the receiving unit 121b receives ultrasonic waves passing through the recording material P. Figure 21 This is a flowchart for calculating the weight of the recording material P, and Figure 22A , Figure 22B , Figure 22C , Figure 22D , Figure 22E , Figure 22F and Figure 22GThis is a timing diagram showing the states of signals and voltages, for example, those related to the processing used to calculate weight. Figure 18 and Figures 19A to 19G The components shown are assigned the same reference characters, which are omitted from the description here. The parts assigned the same reference characters perform the same functions and operations, hence the description is omitted.

[0207] In step S1100, in response to receiving a print instruction, the control unit 120 begins the paper feeding operation. In step S1101, the control unit 120 outputs a low signal as a switching signal for the peak detection signal to be output by the peak detection unit 120d, such as... Figure 22B As shown in the image.

[0208] In step S1102, the transmission indication unit 120a included in the control unit 120 sets the driving voltage to be output by the transmission circuit unit 122 to 10V, such as Figure 22D As shown in the diagram. Therefore, the amplification switching indication unit 120B sets the amplification of the received signal from the receiving detection unit 123 to 1x, as shown in the diagram. Figure 22C As shown in the image.

[0209] In step S1103, the control unit 120 performs the following processing after recording the timing when material P has not yet reached the ultrasonic sensor 121 after the paper feeding operation begins. Therefore, as Figure 22A As shown, the control unit 120 begins to measure the received level of the ultrasonic wave obtained when the receiving unit 121b receives the ultrasonic wave without passing through the recording material P. The control unit 120 outputs a high signal from the transmission indication unit 120a to the transmission circuit unit 122 as a drive signal, as shown. Figure 22E As shown in the diagram. In response to the drive signal output from the transmission indicator unit 120a, the transmission circuit unit 122 inputs a 10V voltage as an output signal to the USS terminal of the transmission unit 121a, as shown in the diagram. Figure 22F As shown in the diagram. At this time, a pulse train signal with a pulse wave voltage of 10V is input from the transmitting circuit unit 122 to the USS terminal. Furthermore, in the sixth exemplary embodiment, regarding the driving signal, for example, the frequency is set to 40kHz, the number of pulses is set to 2, and the duration of the pulse train signal is set to 10 milliseconds.

[0210] In step S1104, the control unit 120 detects the first waveform Va1 of the detection signal and detects its peak value. The detection of the peak value of the first waveform Va1 is described below.

[0211] The receiving detection unit 123 receives the received signal output from the receiving unit 121b after the drive signal is input to the transmitting unit 121a as input. Then, the receiving detection unit 123 begins detecting the received signal as a detection signal after a predetermined time T1 synchronized with the drive signal. More specifically, after the predetermined time T1 synchronized with the drive signal, when the detection signal exceeds a reference value (e.g., set to 0V), the receiving detection unit 123 begins detecting the detection signal and continues detecting the detection signal until the detection signal returns to the reference value. In the sixth exemplary embodiment, it is assumed that the predetermined time T1 is a time calculated based on the relationship between the distance between the transmitting unit 121a and the receiving unit 121b, pre-measured during the manufacturing process, and the speed of sound of the ultrasonic wave pre-detected by an ultrasonic sensor during the manufacturing process. Furthermore, the predetermined time T1 is also referred to as the "first time," and the time from when the control unit 120 begins detecting the detection signal until the detection signal returns to the reference value is also referred to as the "second time." Furthermore, assuming that the period from the first time to the second time is the period during which a wave with an amplitude lower than a first value is output, where the first value is the maximum amplitude of the wave that the receiving detection unit 123 can output. In this way, the control unit 120 performs detection of the detection signal during the period from when the drive input is input to the transmitting unit 121a for a predetermined time T1 until the second time has elapsed, thereby calculating the received level Va1. Furthermore, in the sixth exemplary embodiment, the first waveform Va1 is also referred to as the "first wave," and the value related to the amplitude that serves as the received level Va1 is also referred to as "amplitude information about the first wave."

[0212] In step S1105, the control unit 120 outputs a high signal as a switching signal for the peak detection signal to be output by the peak detection unit 120d, such as... Figure 22B As shown in the image.

[0213] In step S1201, the transmission indication unit 120a included in the control unit 120 sets the driving voltage to be output by the transmission circuit unit 122 to 20V, such as Figure 22D As shown in the diagram. Therefore, in step S1202, the amplification switching indication unit 120B sets the amplification of the received signal from the receiving detection unit 123 to 5 times, as shown in the diagram. Figure 22C As shown in the image.

[0214] In step S1107, the control unit 120 performs the following processing based on whether the leading edge of the recording material P has reached the alignment sensor 6. If it is determined that the leading edge of the recording material P has reached the alignment sensor 6 ("yes" in step S1107), the control unit 120 advances the processing to step S1108.

[0215] In step S1108, in order to detect the timing of the arrival of the leading edge of the recording material P at the ultrasonic sensor 121 after reaching the alignment sensor 6, the control unit 120 starts counting the number of steps S of the pulse motor (not shown).

[0216] In step S1109, the control unit 120 advances the process to step S1203 based on whether the count value of step number S has reached a predetermined value (100). If it is determined that the count value of step number S has reached the predetermined value (100) ("Yes" in step S1109), the control unit 120 advances the process to step S1203.

[0217] In step S1203, the control unit 120 outputs a high signal from the transmission indicator unit 120a to the transmission circuit unit 122 as a drive signal, such as... Figure 22E As shown in the figure. The control unit 120 causes the transmitting circuit unit 122 to output an output signal to drive the ultrasonic sensor 121, and begins to measure the received signal level performed by the receiving detection unit 123 when the receiving unit 121b receives the ultrasonic waves passing through the recording material P.

[0218] At this time, the transmitting circuit unit 122 inputs a 20V voltage to the USS terminal of the transmitting unit 121a according to the drive signal output from the transmitting indicator unit 120a, such as... Figure 22F As shown in the image.

[0219] In step S1111, the control unit 120 detects the third waveform Vp3 of the detection signal and detects its peak value. The detection of the peak value of the third waveform Vp3 is described below.

[0220] The receiving detection unit 123 receives the received signal output from the receiving unit 121b after the drive signal is input to the transmitting unit 121a. Then, similar to the detection of the detection waveform Va1 obtained when the receiving unit 121b receives ultrasound waves that do not pass through the recording material P, the receiving detection unit 123 begins detecting the received signal as a detection signal after a predetermined time T2 synchronized with the drive signal. More specifically, after the predetermined time T2 synchronized with the drive signal, when the detection signal exceeds a reference value (e.g., set to 0V), the receiving detection unit 123 begins detecting the detection signal and continues detecting the detection signal until the detection signal returns to the reference value. In the sixth exemplary embodiment, the predetermined time T2 is assumed to be a time calculated based on the relationship between the distance between the transmitting unit 121a and the receiving unit 121b, pre-measured during manufacturing, and the speed of sound of the ultrasound waves pre-detected by the ultrasonic sensor during manufacturing, and is assumed to be longer than the predetermined time T1.

[0221] Furthermore, the predetermined time T2 is also referred to as the "third time," and the time from when the control unit 120 starts detecting the detection signal until the detection signal returns to the reference value is also referred to as the "fourth time." Furthermore, it is assumed that the period from the third time to the fourth time is the period during which a wave with an amplitude lower than a first value is output, where the first value is the maximum amplitude of the wave that the receiving detection unit 123 can output. In this way, the control unit 120 performs detection of the detection signal during the period from when the drive input is input to the transmitting unit 121a for the predetermined time T2 until the fourth time has elapsed, thereby calculating the received level Vp3. Furthermore, in the sixth exemplary embodiment, the third waveform Vp3 is also referred to as the "second wave," and the value related to the amplitude that serves as the received level Vp3 is also referred to as "amplitude information about the second wave."

[0222] In step S1112, the control unit 120 substitutes the received levels Va1 and Vp3 into the aforementioned equation (2) to calculate the position correction coefficient T. Subsequent processing operations are similar to... Figure 18 The processing operations shown are the same, therefore, they are omitted from the description.

[0223] Furthermore, in the sixth exemplary embodiment, the amplitude of the output signal is switched by switching the driving voltage, depending on the presence or absence of the recording material P. However, as... Figure 23 As shown, the control unit 120 can be configured to further include an amplification switching indicator unit 120e, which controls the amplification of the voltage input to the transmitting circuit unit 122 and performs the following control. Therefore, the control unit 120 can be configured to set the drive voltage to a constant value regardless of the presence or absence of the recording material P, and to switch the amplification switching signal output from the amplification switching indicator unit 120e based on the presence or absence of the recording material P, thereby switching the amplification of the voltage input to the transmitting circuit unit 122. In this case, for example, the control unit 120 sets the drive voltage to 20V regardless of the presence or absence of the recording material P, and sets the amplification to 1 / 2 times when the receiving unit 121b receives ultrasound waves that do not pass through the recording material P. Furthermore, the control unit 120 sets the amplification to 1 times when the receiving unit 121b receives ultrasound waves that pass through the recording material P.

[0224] In this manner, in the sixth exemplary embodiment, the control unit 120 switches the amplitude of the output signal depending on the presence or absence of the recording material P, and the peak detection unit 120d switches the waveform used to detect the peak value of the received signal depending on the presence or absence of the recording material P. Therefore, when the receiving unit 121b receives ultrasound waves that do not pass through the recording material P, for example, the peak detection unit 120d selects the peak value of the first waveform of the received signal as the peak detection signal. Furthermore, when the receiving unit 121b receives ultrasound waves that pass through the recording material P, for example, the control unit 120 makes the amplitude of the output signal greater than the amplitude of the output signal when the receiving unit 121b receives ultrasound waves that do not pass through the recording material P. Then, the peak detection unit 120d selects the peak value of the third waveform of the received signal as the peak detection signal. Therefore, when the receiving unit 121b receives ultrasound waves that pass through the recording material P, the amplification of the received ultrasound signal can be prevented or reduced, thus reducing the influence of noise present in the circuit receiving the ultrasound waves on the weight detection result.

[0225] Furthermore, in the sixth exemplary embodiment, a method for detecting a detection signal obtained at a predetermined time synchronized with a drive signal is described as a method for switching the waveform used to detect the peak value of the received signal depending on the presence or absence of the recording material P, with the peak detection unit 120d switching the waveform used to detect the peak value. However, the method for switching the waveform used to detect the peak value is not limited to this. For example, the method for switching the waveform used to detect the peak value may include a method in which the receive level detection unit 120c uses a digital signal obtained by converting the detection signal generated by the receive detection unit 123 to detect the waveform of the detection signal, thereby counting the waveform. At this time, the receive level detection unit 120c may count the points where the digital signal of the detection signal becomes the maximum value and the waveform reaches the peak value, or it may count the points where the digital signal of the detection signal becomes 0 and the waveform intersects the horizontal axis.

[0226] Furthermore, in the sixth exemplary embodiment, the method for switching the waveform used to detect peaks may include the following methods. For example, the method may include pre-detecting a detection signal using an ultrasonic sensor during the manufacturing process, setting a threshold Vth to a value at which the received level of the detection signal will not become saturated, and detecting the time from when the drive input is input to the transmitting unit 121a until the detection signal exceeds the threshold Vth. In this case, the threshold Vth is set to a value at which the received level of the detection signal will not become saturated, that is, a value less than the upper limit of the signal that can be used to detect the received signal by the receiving detection unit 123.

[0227] When the receiving unit 121b receives ultrasonic waves that do not pass through the recording material P, the time from when the drive input is input to the transmitting unit 121a until the detection signal becomes greater than or equal to the threshold Vth is represented by Ta. Furthermore, when the receiving unit 121b receives ultrasonic waves that pass through the recording material P, the time from when the drive input is input to the transmitting unit 121a until the detection signal becomes greater than or equal to the threshold Vth is represented by Tp. A method for detecting the weight of the recording material P based on the times Ta and Tp thus obtained can also be used. Furthermore, time Ta is also referred to as the "first time period," and time Tp is also referred to as the "second time period."

[0228] In using this method, to switch the amplitude of the output signal depending on the presence or absence of the recording material P, the following configuration can be adopted, wherein the driving voltage is kept constant regardless of the presence or absence of the recording material P, and the frequency of the driving signal output from the transmission indicator unit 120a is switched depending on the presence or absence of the recording material P. For example, the frequency of the driving signal on which the amplitude of the ultrasonic wave becomes at its maximum value is assumed to be a first frequency, and the frequency of the driving signal on which the amplitude of the ultrasonic wave becomes less than the amplitude of the ultrasonic wave obtained when the driving signal has the first frequency is assumed to be a second frequency. In this case, when the receiving unit 121b receives ultrasonic waves passing through the recording material P, the transmission indicator unit 120a outputs a pulse wave with the first frequency as a driving signal. Furthermore, when the receiving unit 121b receives ultrasonic waves that do not pass through the recording material P, the transmission indicator unit 120a outputs a pulse wave with the second frequency as a driving signal. This allows the transmission unit 121a to output a larger amplitude ultrasonic wave when the receiving unit 121b receives ultrasonic waves passing through the recording material P, compared to the case where the receiving unit 121b receives ultrasonic waves that do not pass through the recording material P. Therefore, the increase in signal-to-noise ratio caused by the amplification of the received signal when the ultrasonic waves passing through the recording material P are received in the receiving unit 121b can be prevented or reduced. Consequently, the weight of the recording material P can be detected with higher accuracy than in conventional methods.

[0229] Furthermore, a configuration can be adopted in which the driving voltage and frequency of the driving signal to be output from the transmission indication unit 120a are kept constant, regardless of the presence or absence of the recording material P, and the duty cycle between the high and low signals in the driving signal switches depending on the presence or absence of the recording material P. This allows the transmission unit 121a to output a larger amplitude ultrasonic wave when the receiving unit 121b receives ultrasonic waves passing through the recording material P, compared to the case where the receiving unit 121b receives ultrasonic waves passing through the recording material P. Therefore, the increase in signal-to-noise ratio caused by the amplification of the received signal when the receiving unit 121b receives ultrasonic waves passing through the recording material P can be prevented or reduced.

[0230] Other embodiments

[0231] One or more embodiments of the present invention can also be implemented by a computer of a system or device and by a method executed by the computer of the system or device, wherein the computer of the system or device reads and executes computer-executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be more fully referred to as a "non-transitory computer-readable storage medium") to perform one or more functions of the above-described embodiments and / or includes one or more circuits (e.g., application-specific integrated circuits (ASICs)) for performing one or more functions of the above-described embodiments, and the above-described method executed by the computer of the system or device implements one or more embodiments of the present invention by, for example, reading and executing computer-executable instructions from the storage medium to perform one or more functions of the above-described embodiments and / or controlling one or more circuits to perform one or more functions of the above-described embodiments. The computer may include one or more processors (e.g., a central processing unit (CPU), a microprocessor unit (MPU)) and may include a network of individual computers or individual processors to read and execute computer-executable instructions. The computer-executable instructions may be provided to the computer, for example, from a network or a storage medium. Storage media may include, for example, hard disks, random access memory (RAM), read-only memory (ROM), storage for distributed computing systems, and optical discs (such as optical discs (CD), digital versatile discs (DVD), or Blu-ray discs (BD)). TM One or more of the following: flash memory devices, memory cards, etc.

[0232] Other embodiments

[0233] The embodiments of the present invention can also be implemented by providing software (programs) that perform the functions of the above embodiments to a system or device via a network or various storage media, and the computer or central processing unit (CPU) or microprocessor unit (MPU) of the system or device reads out and executes the program.

[0234] While the invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the claims should be given the broadest interpretation to include all such modifications and equivalent structures and functions.

Claims

1. A recording material detection device, characterized in that, The recording material detection device includes: An ultrasonic sensor includes a transmitting unit that emits ultrasonic waves and a receiving unit that receives ultrasonic waves, the transmitting unit and the receiving unit being arranged opposite each other across a transmission path through which recording material is transmitted. An indicating unit is configured to input a first driving input and a second driving input to the transmitting unit, the first driving input causing the transmitting unit to emit an ultrasonic wave with a first maximum amplitude, and the second driving input causing the transmitting unit to emit an ultrasonic wave with a second maximum amplitude greater than the first maximum amplitude; and The detection unit is configured to detect information about the weight of the recording material based on a first value and a second value, the first value being obtained by the receiving unit receiving ultrasonic waves emitted from the transmitting unit supplied with the first drive input and not passing through the recording material, and the second value being obtained by the receiving unit receiving ultrasonic waves emitted from the transmitting unit supplied with the second drive input and passing through the recording material.

2. The recording material detection device according to claim 1, wherein, The indicating unit includes a first output circuit unit and a second output circuit unit, wherein the first output circuit unit is connected to a first terminal of the transmitting unit and the second output circuit unit is connected to a second terminal of the transmitting unit.

3. The recording material detection device according to claim 2, in, The indicating unit further includes a third output circuit unit, which is connected to the second terminal of the transmitting unit, and The recording material detection device further includes a first switching unit, which is configured to switch between connecting the second output circuit unit to the second terminal of the transmitting unit and connecting the third output circuit unit to the second terminal of the transmitting unit.

4. The recording material detection device according to claim 3, wherein, When the first drive input is input from the indicator unit to the transmitting unit, The first switching unit connects the third output circuit unit to the second terminal, and The indicator unit switches between a first state and a second state. The first state is to output the first drive input from the first output circuit unit and output an input corresponding to ground from the third output circuit unit. The second state is to output an input corresponding to ground from the first output circuit unit and output an input corresponding to ground from the third output circuit unit.

5. The recording material detection device according to claim 3, wherein, When the second drive input is input from the indication unit to the transmitting unit, The first switching unit connects the second output circuit unit to the second terminal, and The indicator unit switches between a third state and a fourth state. In the third state, the second drive input is output from the first output circuit unit and the input corresponding to ground is output from the second output circuit unit. In the fourth state, the input corresponding to ground is output from the first output circuit unit and the second drive input is output from the second output circuit unit.

6. The recording material detection device according to claim 2, further comprising: A fourth output circuit unit is connected to the second output circuit unit and is configured to output a drive signal to the second output circuit unit; The fifth output circuit unit is connected to the second output circuit unit and is configured to output an input corresponding to ground to the second output circuit unit; and The second switching unit is configured to switch between connecting the fourth output circuit unit to the second output circuit unit and connecting the fifth output circuit unit to the second output circuit unit.

7. The recording material detection device according to claim 6, wherein, When the first drive input is supplied from the indicating unit to the transmitting unit The second switching unit connects the fifth output circuit unit to the second output circuit unit, and The indicator unit switches between a fifth state and a sixth state. The fifth state is when the first output circuit unit outputs the first drive input and the second output circuit unit outputs an input corresponding to ground. The sixth state is when the first output circuit unit outputs an input corresponding to ground and the second output circuit unit outputs an input corresponding to ground.

8. The recording material detection device according to claim 6, wherein, When the second drive input is supplied from the indicating unit to the transmitting unit The second switching unit connects the fourth output circuit unit to the second output circuit unit, and The indicator unit switches between a seventh state and an eighth state. The seventh state is when the second drive input is output from the first output circuit unit and the input corresponding to ground is output from the second output circuit unit. The eighth state is when the input corresponding to ground is output from the first output circuit unit and the second drive input is output from the second output circuit unit.

9. The recording material detection device according to claim 2, wherein, When the first drive input is supplied from the indicating unit to the transmitting unit The indicator unit switches between a ninth state and a tenth state. The ninth state is when the first output circuit unit outputs the first drive input and the second output circuit unit outputs an input corresponding to ground. The tenth state is when the first output circuit unit outputs an input corresponding to ground and the second output circuit unit outputs the first drive input.

10. The recording material detection device according to claim 2, wherein, When the second drive input is supplied from the indicating unit to the transmitting unit The indicator unit switches between an eleventh state and a twelfth state. The eleventh state is when the second drive input is output from the first output circuit unit and the input corresponding to ground is output from the second output circuit unit. The twelfth state is when the input corresponding to ground is output from the first output circuit unit and the second drive input is output from the second output circuit unit.

11. The recording material detection device according to claim 2, wherein, When the first drive input is supplied from the indicating unit to the transmitting unit The indicator unit switches between a thirteenth state and a fourteenth state. The thirteenth state is when the first output circuit unit outputs the first drive input and the second output circuit unit outputs an input corresponding to ground. The fourteenth state is when the first output circuit unit outputs an input corresponding to ground and the second output circuit unit outputs an input corresponding to ground.

12. The recording material detection device according to claim 2, wherein, When the second drive input is supplied from the indicating unit to the transmitting unit The indicator unit switches between a fifteenth state and a sixteenth state. The fifteenth state is when the second drive input is output from the first output circuit unit and the input corresponding to ground is output from the second output circuit unit. The sixteenth state is when the input corresponding to ground is output from the first output circuit unit and the input corresponding to ground is output from the second output circuit unit.

13. An image forming apparatus, characterized in that, The image forming apparatus includes: Image forming units are configured to form an image on recording material; and The recording material detection device according to claim 1, in, The image forming unit forms an image based on the detection results obtained by performing detection through the recording material detection device.

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