JP7555849B2 - Image forming device - Google Patents

Description

This disclosure relates to an image forming apparatus.

Conventionally, image forming devices equipped with a function for automatically determining the type of recording material are known. During image forming operations, by setting operating conditions suitable for the determined type of recording material, it is possible to reduce power consumption during operation or improve image quality. If operating conditions suitable for the type of recording material are automatically set, the burden of setting work on the user is also reduced. Patent Document 1 discloses a technology in which ultrasonic waves are irradiated onto the recording material, the basis weight (mass per unit area) of the recording material is detected based on the transmittance of the ultrasonic waves transmitted through the recording material, and the type of recording material is determined from the detected basis weight.

There is also a known method of automatically detecting operating sounds generated in an image forming device and using the detected operating sounds to diagnose abnormalities. Patent Document 2 discloses a technology in which, in a management system that centrally manages multiple image forming devices, the sounds generated by each device are compared with normal operating sounds to determine where an abnormality has occurred in each device.

JP 2009-29622 A Japanese Patent Application Publication No. 7-302019

When both the functions of determining the type of recording material and diagnosing abnormalities are incorporated into the same device, inconveniences such as an increase in the size of the device, an increase in the number of parts, and an increase in costs can arise. In order to avoid these inconveniences, a configuration in which a single receiving means (e.g., a microphone) is shared to receive both sound waves and ultrasonic waves can be considered. However, in a configuration in which the receiving means is shared, it is difficult to simultaneously detect the basis weight and the operating sound, and it is important to appropriately control the timing of each detection.

Therefore, the present disclosure aims to provide a mechanism for appropriately controlling the timing of detecting basis weight and operating sounds.

According to one aspect, there is provided an image forming apparatus that forms an image on a recording material, comprising: a transmitting means for transmitting ultrasonic waves toward a transport path along which the recording material is transported; a receiving means for receiving sound waves generated in the image forming apparatus or the ultrasonic waves transmitted by the transmitting means ; and a control means for switching from a first operation to a second operation when a predetermined condition is satisfied, wherein the first operation is for detecting the basis weight of the recording material based on the ultrasonic waves received by the receiving means, and the second operation is for acquiring information about the sound waves received by the receiving means .

This disclosure makes it possible to appropriately control the timing of detecting basis weight and operating sounds.

FIG. 2 is a diagram illustrating an example of the configuration of an image forming unit according to an embodiment. FIG. 1 is a block diagram showing an example of a configuration of an image forming apparatus according to an embodiment. FIG. 2 is a block diagram showing an example of a functional configuration of an image forming apparatus according to an embodiment. FIG. 4 is a block diagram showing an example of a detailed configuration of a switching unit shown in FIG. 3 . FIG. 4 is a block diagram showing an example of a detailed configuration of a basis weight detection unit shown in FIG. 3 . 4 is a block diagram showing an example of a detailed configuration of an operation sound detection unit shown in FIG. 3 . 6 is a timing chart showing a first control pattern for switching between a basis weight detection mode and an operation sound detection mode. 10 is a timing chart showing a second control pattern for switching between the basis weight detection mode and the operation sound detection mode. 4 is a block diagram showing some examples of a detailed configuration of the control unit shown in FIG. 3; 10 is a timing chart showing an example of a transition of a detection mode when a control pattern is changed. 10 is a timing chart showing another example of the transition of the detection mode when the control pattern is changed. 10 is a flowchart showing an example of the flow of a detection mode switching process of a first control pattern. 10 is a flowchart showing an example of the flow of a detection mode switching process of a second control pattern. 10 is a flowchart showing an example of a process flow for changing a control pattern according to the first embodiment. 10 is a flowchart showing an example of a process flow for changing a control pattern according to the second embodiment. 13 is a flowchart showing an example of a process flow for changing a control pattern according to the third embodiment.

The following embodiments are described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe multiple features, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicate explanations are omitted.

<<1. Schematic configuration>>
In this section, an example in which the technology according to the present disclosure is applied to a printer will be mainly described. However, the technology according to the present disclosure can be widely applied to image forming apparatuses (e.g., copiers, facsimiles, or multifunction machines) that are not limited to printers. Unless otherwise specified, each of the components such as an apparatus, device, module, and chip described below may be composed of a single entity, or may be composed of multiple physically different entities.

1 is a diagram showing an example of the configuration of an image forming unit 1 according to an embodiment. In FIG. 1, the suffixes Y, M, C, and K of the reference symbols indicate that the colors of the toner handled by the corresponding members are yellow, magenta, cyan, and black, respectively. However, in the following description, when it is not necessary to distinguish between colors, reference symbols without the suffixes are used. The photoconductor 11, which is an image carrier, is rotated clockwise in the figure during image formation. The charging roller 12 charges the surface of the photoconductor 11 to a predetermined potential. The optical unit 13 exposes the photoconductor 11 to light to form an electrostatic latent image on the photoconductor 11. The developer 14 has a developer, and develops the electrostatic latent image on the photoconductor 11 with the developing roller 15 to form a developer image (image). The primary transfer roller 16 outputs a primary transfer bias, transfers the electrostatic latent image on the photoconductor 11 to the intermediate transfer belt 17, which is an image carrier, and forms a developer image on the intermediate transfer belt 17. In addition, by transferring the developer images formed on the photoreceptors 11Y, 11M, 11C, and 11K onto the intermediate transfer belt 17 in a superimposed manner, a full-color developer image can be formed on the intermediate transfer belt 17.

The intermediate transfer belt 17 is stretched by a drive roller 18, a tension roller 25, and a secondary transfer opposing roller 20, and is driven to rotate counterclockwise in the figure in response to the rotation of the drive roller 18 during image formation. As a result, the developer image transferred to the intermediate transfer belt 17 is transported to a position opposite the secondary transfer roller 19. On the other hand, the cassette 2 is a holding means for accumulating and holding the recording material P before transport. The recording material (also called paper) P held by the cassette 2 is fed to the transport path by the feed roller 4. The separation roller 5 separates the recording material P one sheet at a time when feeding the recording material P from the cassette 2. The feed roller 4 and the separation roller 5 constitute a feeding section. While an electromagnetic clutch (not shown) is in the ON state, a rotational driving force from a motor (not shown) is transmitted to the feed roller 4, which rotates the feed roller 4. While the electromagnetic clutch is in the OFF state, the transmission of the rotational driving force from the motor (not shown) to the feed roller 4 is cut off. The conveying roller pair 6 conveys the fed recording material P downstream of the conveying path, through the registration roller pair 7, toward the opposing position of the secondary transfer roller 19. The secondary transfer roller 19 outputs a secondary transfer bias to transfer the developer image on the intermediate transfer belt 17 to the recording material P. The developer that is not transferred to the recording material P and remains on the intermediate transfer belt 17 is collected by the cleaning blade 35 in the cleaning section 36. After the developer image is transferred, the recording material P is conveyed to the fixing device 21. The fixing device 21 pressurizes and heats the recording material P to fix the developer image to the recording material P. After the developer image is fixed, the recording material P is discharged to the paper discharge tray by the discharge roller pair 22. Each roller pair, including the conveying roller pair 6 and the discharge roller pair 22, is configured as a roller unit.

The image forming unit 1 has a transmitting unit 31 that transmits ultrasonic waves toward the transport path along which the recording material P is transported. The transmitting unit 31 is disposed near the transport path (in the example of FIG. 1, upstream of the secondary transfer roller 19 in the transport direction). The image forming unit 1 further has a receiving unit 71 that receives sound waves or ultrasonic waves. The sound waves here may include audible frequency components and inaudible frequency components (e.g., ultrasonic waves). The receiving unit 71 is disposed at a position facing the transmitting unit 31 across the transport path. Therefore, the ultrasonic waves transmitted by the transmitting unit 31 are received by the receiving unit 71 via the transport path. For example, the transmitting unit 31 has a piezoelectric element (also called a piezo element), which is a mutual conversion element that converts mechanical displacement and electrical signals into each other. The receiving unit 71 has a MEMS (Micro-Electro Mechanical System) microphone that converts the vibration displacement of a diaphragm due to pressure into a voltage change and outputs it. In addition, any receiving means other than a MEMS microphone, such as a condenser microphone, may be used as long as it is capable of receiving both ultrasonic waves and sound waves in the audible range.

In the example of FIG. 1, the image forming unit 1 further includes a cassette sensor 91. The cassette sensor 91 detects a user operation of pulling out the cassette 2 from the main body of the device or inserting the cassette 2 into the main body. The cassette sensor 91 outputs a sensor signal indicating the detection result of these user operations to the CPU 207 described later. The user can pull out the cassette 2 from the main body of the device and, for example, replenish the cassette 2 with recording material or replace the recording material contained in the cassette 2 with another type of recording material.

2 is a block diagram showing an example of the configuration of the image forming apparatus 100 according to the present embodiment. Referring to FIG. 2, the image forming apparatus 100 includes a printer unit 200, a video controller 204, an operation/display unit 205, and a communication I/F 206. The printer unit 200 includes an image forming unit 1, a CPU 207, a ROM 208, a RAM 209, a system bus 210, and an I/O port 211. The video controller 204 acquires information indicating the state of the image forming unit 1 from the printer unit 200, and controls the screen display by the operation/display unit 205 based on the acquired information. The video controller 204 also accepts a print job from an external host computer (not shown) via the communication I/F 206, and outputs a print instruction together with image data for printing to the printer unit 200. The operation/display unit 205 has an operation unit (e.g., an operation panel or an operation button (not shown)) that accepts operations by a user, and a display unit that displays information. The operation/display unit 205 displays information indicating the state of the image forming unit 1 on a screen under the control of, for example, the video controller 204. The communication interface (I/F) 206 is an interface for communication between the image forming apparatus 100 and other devices. The communication I/F 206 may be a wired communication I/F or a wireless communication I/F. The CPU (Central Processing Unit) 207 is a processor that controls the overall functions of the image forming apparatus 100. The ROM (Read-Only Memory) 208 is a non-volatile memory that stores programs and data to be executed by the CPU 207. The RAM (Random Access Memory) 209 is a volatile memory that provides the CPU 207 with a temporary storage area for work. The CPU 207 loads a computer program stored in the ROM 208 into the RAM 209 and executes it to realize various control functions of the image forming apparatus 100, which will be described later. The system bus 210 is a signal line that interconnects the CPU 207, ROM 208, RAM 209, and I/O port 211. The I/O (Input/Output) port 211 is a collection of ports for connecting various actuators and sensors of the image forming unit 1 described with reference to FIG. 1 to the printer unit 200. The CPU 207 controls the transport of the recording material P in the image forming unit 1 and the formation of an image on the recording material P via the I/O port 211.

<<2. Functional configuration example>>
3 is a block diagram showing an example of a functional configuration of the image forming apparatus 100 according to the present embodiment. Referring to FIG. 3, the image forming apparatus 100 includes a transmission unit 31, a reception unit 71, a switching unit 310, a basis weight detection unit 320, a condition setting unit 330, an operation sound detection unit 340, a diagnosis unit 350, and a control unit 360.

<2-1. Switching section>
In this embodiment, a single receiver 71 is shared for detecting basis weight and detecting operation sound. In order to operate these detection functions accurately, it is necessary to distribute the received signal from the receiver 71 to an appropriate signal processing path at an appropriate timing. The switching unit 310 is responsible for this signal distribution. Specifically, the switching unit 310 switches the output destination of the received signal from the receiver 71 between the signal processing path to the basis weight detection unit 320 and the signal processing path to the operation sound detection unit 340. FIG. 4 is a block diagram showing an example of a detailed configuration of the switching unit 310 shown in FIG. 3. Referring to FIG. 4, the switching unit 310 includes a switching circuit 311, an analog filter 312, an amplifier 313, and an amplifier 315.

When the control unit 360, which will be described later, sets the basis weight detection mode, the switching circuit 311 outputs the received signal from the receiving unit 71 to the analog filter 312 in accordance with a control signal indicating the basis weight detection mode. When the control unit 360 sets the operation sound detection mode, the switching circuit 311 outputs the received signal from the receiving unit 71 to the amplifier unit 315 in accordance with a control signal indicating the operation sound detection mode. The analog filter 312 and the amplifier unit 313 belong to the signal processing path to the basis weight detection unit 320. The analog filter 312 removes signal components in bands other than the ultrasonic band contained in the received signal by filtering the received signal input from the switching circuit 311 in the analog domain. The ultrasonic band here may be, for example, a band from 35 KHz to 45 KHz. That is, the analog filter 312 may be a band pass filter. The amplifier 313 amplifies the signal level (e.g., voltage) of the ultrasonic band component of the received signal that has passed through the analog filter 312, and outputs the amplified signal (hereinafter referred to as the ultrasonic level signal) to the weight detection unit 320. The amplifier 315 belongs to the signal processing path to the operation sound detection unit 340. The amplifier 315 amplifies the signal level of the received signal input from the switching circuit 311, and outputs the amplified signal (hereinafter referred to as the sound wave level signal) to the operation sound detection unit 340.

Typically, in the basis weight detection mode, the vibration displacement of the receiving unit 71 caused by the internal operating sound of the image forming device 100 is greater than the vibration displacement of the receiving unit 71 caused by the ultrasonic waves transmitted from the transmitting unit 31. Therefore, by setting the signal level amplification factor in the amplifier 315 to a value lower than the signal level amplification factor in the amplifier 313, the signal levels output from both signal processing paths can be normalized, and the detection performance of the basis weight detection and the operating sound detection can be stabilized.

<2-2. Basis weight detection unit>
The basis weight detection unit 320 detects the basis weight of the recording material conveyed on the conveying path based on the ultrasonic waves received by the receiving unit 71. Basis weight means the mass per unit area of the recording material, and can be expressed in units of [g/ ^m2 ]. Fig. 5 is a block diagram showing an example of a detailed configuration of the basis weight detection unit 320 shown in Fig. 3. Referring to Fig. 5, the basis weight detection unit 320 includes a communication control unit 321, a drive signal generation unit 322, an AD conversion unit 324, a peak detection unit 325, a storage unit 326, and a calculation unit 327.

In the basis weight detection mode, the communication control unit 321 instructs the drive signal generation unit 322 to output a drive signal to the transmission unit 31 at a timing specified by the control unit 360. Based on the instruction input from the communication control unit 321, the drive signal generation unit 322 generates a drive signal for causing the transmission unit 31 to transmit ultrasonic waves, and outputs the generated drive signal to the transmission unit 31. In response to the input of the drive signal from the drive signal generation unit 322, the transmission unit 31 transmits ultrasonic waves toward the conveying path (more specifically, toward the detection position 329 of the conveying path). The frequency of the ultrasonic waves transmitted by the transmission unit 31 may be any frequency belonging to the ultrasonic band, depending on the configuration of the transmission unit 31 and the receiving unit 71 and the desired detection accuracy. For example, the frequency of the ultrasonic waves transmitted by the transmission unit 31 may be 32 KHz. In the basis weight detection mode, an ultrasonic level signal indicating the signal level after amplification of the ultrasonic band component of the sound wave received by the receiving unit 71 is input from the switching unit 310 to the AD conversion unit 324. The AD conversion unit 324 converts the signal domain of the ultrasonic level signal from an analog domain to a digital domain to generate a digital ultrasonic level signal. The peak detection unit 325 judges the peak value (maximum value) of the ultrasonic level signal input from the AD conversion unit 324, and stores the judged peak value in the storage unit 326. As will be described later, the control unit 360 causes the basis weight detection unit 320 to judge the peak value of the ultrasonic level signal at least once each at a timing when the recording material P is not present at the detection position 329 and a timing when the recording material P is present at the detection position 329. The storage unit 326 stores the multiple peak values thus judged. The calculation unit 327 calculates the ratio of the peak value of the ultrasonic level signal at a timing when the recording material P is present to the peak value of the ultrasonic level signal at a timing when the recording material P is not present as an attenuation coefficient, and stores the calculated attenuation coefficient in the storage unit 326. The attenuation coefficient has a correlation with the basis weight of the recording material P, and substantially represents the basis weight of the recording material P. In order to reduce detection errors, the basis weight detection unit 320 may determine the peak value of the ultrasonic level signal multiple times (e.g., five times) when the recording material P is present at the detection position 329, and calculate the attenuation coefficient using a representative value (e.g., average value) of the determination results. The communication control unit 321 reads out the basis weight data (value of the attenuation coefficient) from the memory unit 326, and outputs the read out basis weight data to the condition setting unit 330.

<2-3. Condition setting section>
The condition setting unit 330 sets the operating conditions of the image forming operation in the image forming apparatus 100 based on the basis weight of the recording material detected by the basis weight detection unit 320. The operating conditions of the image forming operation may include, for example, one or more of the following: the conveying speed of the recording material, the applied bias (the voltage applied to the secondary transfer roller 19) for transferring the toner to the recording material, and the heating temperature (the target temperature of the fixing device 21) for fixing the toner to the recording material. For example, the condition setting unit 330 may determine the type of the recording material based on the basis weight of the detected recording material, and set the value of the operating conditions previously associated with the determined type to the corresponding member of the image forming unit 1. By setting the operating conditions suitable for the type of recording material automatically determined in this way, the power consumption of the image forming operation can be saved, the image quality can be improved, and the burden of the setting work by the user can be reduced.

<2-4. Operation sound detection unit>
The operation sound detection unit 340 detects operation sound generated in the image forming apparatus 100 based on sound waves received by the receiving unit 71. Fig. 6 is a block diagram showing an example of a detailed configuration of the operation sound detection unit 340 shown in Fig. 3. Referring to Fig. 6, the operation sound detection unit 340 includes an AD conversion unit 341, a digital filter 342, a calculation unit 343, a storage unit 344, and a communication control unit 346.

In the operation sound detection mode, the receiver 71 receives sound waves generated in the image forming apparatus 100. These sound waves include, for example, audible frequency components caused by the operation of the image forming unit 1, and displace the diaphragm of the MEMS microphone in the same manner as ultrasonic waves. A sound level signal indicating the signal level after amplification of the sound waves received by the receiver 71 is input from the switching unit 310 to the AD conversion unit 341. The AD conversion unit 341 converts the signal domain of the sound level signal from the analog domain to the digital domain to generate a digital sound level signal. The digital filter 342 filters the sound level signal input from the AD conversion unit 341 in the digital domain to remove signal components in bands other than a specific band contained in the sound level signal, and passes only the signal components in the specific band. The digital filter 342 may variably set the band of the signal components to be passed based on an instruction input from the communication control unit 346. For example, when it is desired to determine whether a specific member has an abnormality, the accuracy of the abnormality diagnosis can be improved by extracting only the signal components in a band specific to the operation sound of the member by the digital filter 342. For example, for the purpose of diagnosing the state of a feeding-related member described later, the digital filter 342 may be set as a low-pass filter that passes frequency components of 500 MHz or less. The calculation unit 343 performs a square calculation and an interval average on the sound level signal that has passed through the digital filter 342, and generates sound level data indicating the average of the absolute values of the sound level for each time interval. The length of the time interval here may be any length, for example, 100 ms. The calculation unit 343 may variably set the length of the time interval depending on the type of the member to be diagnosed for abnormality. The calculation unit 343 stores the generated sound level data in the memory unit 344. The memory unit 344 stores the sound level data for each time interval thus generated. The communication control unit 346 reads out the sound wave level data from the memory unit 344 and outputs the read out sound wave level data to the diagnosis unit 350.

<2-5. Diagnostics>
The diagnosis unit 350 judges whether an abnormality has occurred or whether there is a sign of an abnormality in the image forming apparatus 100 based on the operation sound (represented by the sound level data) detected by the operation sound detection unit 340. For example, the diagnosis unit 350 compares the signal level indicated by the sound level data input from the operation sound detection unit 340 with a judgment threshold for abnormality diagnosis. Then, the diagnosis unit 350 may judge that an abnormality has occurred in the image forming apparatus 100 when the signal level exceeds the judgment threshold. The diagnosis unit 350 may use different judgment thresholds depending on the type of member to be diagnosed for abnormality. In addition, the diagnosis unit 350 may judge that an abnormality has occurred when the signal level exceeds a first judgment threshold, and may judge that there is a sign of an abnormality when the signal level does not exceed the first judgment threshold but exceeds a second judgment threshold. In addition, the diagnosis unit 350 may compare the sound level data with data on the known operation sounds of each member of the image forming unit 1 to judge which member of the image forming unit 1 has an abnormality (or there is a sign of an abnormality).

When the diagnosis unit 350 determines that an abnormality has occurred or that there is a sign of an abnormality, it may notify the user of the result of the determination, for example, by displaying abnormality-related information on the screen of the operation/display unit 205. The abnormality-related information may include, for example, information such as the date and time of the abnormality, the degree of the abnormality, and the location of the abnormality (the member suspected of being abnormal). When the diagnosis unit 350 determines that an abnormality has occurred or that there is a sign of an abnormality, it may transmit the abnormality-related information to another device (for example, a management server, or a user or serviceman's terminal) via the communication I/F 206. The diagnosis unit 350 may also cause the condition setting unit 330 to set special operating conditions for the abnormality. Such automatic abnormality diagnosis can shorten the time required for recovery from the occurrence of an abnormality in the image forming apparatus 100, prevent the occurrence of an abnormality at the stage of its signs, or facilitate the investigation of the cause of the abnormality.

<2-6. Control section>
The control unit 360 controls the timing of the detection of the basis weight by the basis weight detection unit 320 and the detection of the operation sound by the operation sound detection unit 340 so that both functions operate smoothly. Specifically, the control unit 360 causes the switching unit 310 to output the reception signal from the receiving unit 71 to a first path to the operation sound detection unit 340 at a first timing, and causes the operation sound detection unit 340 to detect the operation sound. In addition, the control unit 360 causes the switching unit 310 to output the reception signal from the receiving unit 71 to a second path to the basis weight detection unit 320 at a second timing different from the first timing, and causes the basis weight detection unit 320 to detect the basis weight of the recording material. In this specification, the mode for detecting the operation sound by the operation sound detection unit 340 is expressed as the operation sound detection mode, and the mode for detecting the basis weight by the basis weight detection unit 320 is expressed as the basis weight detection mode.

Figure 7 is a timing chart showing a first control pattern for switching between the basis weight detection mode and the operation sound detection mode. In the first control pattern, the control unit 360 causes the transmission unit 31 to transmit ultrasonic waves at the timing when two detectable positions on the paper pass the detection position 329 on the transport path. As an example, the first detectable position may be a position 10 mm behind the leading edge of the paper, and the second detectable position may be the center position of the paper. In addition, the control unit 360 causes the transmission unit 31 to transmit ultrasonic waves at the timing when no paper is present at the detection position 329. The control unit 360 causes the operation sound detection unit 340 to detect operation sound at a timing different from these timings.

In Figure 7, the horizontal axis represents time, and the vertical axis represents the transport position of the paper along the transport path. The diagonally inclined solid lines in the figure represent the transport positions of the leading and trailing ends of each sheet of paper moving along the transport path. Below the horizontal axis is shown the detection mode set by the control unit 360 at each point in time, with M1 representing the operation sound detection mode and M2 representing the basis weight detection mode. The X marks in the figure represent the timing at which ultrasonic waves are transmitted and received, and the ovals represent the timing at which operation sounds are detected.

Specifically, first, the control unit 360 sets the detection mode to the basis weight detection mode M2 at time _T0 before the conveyance of the paper P1 is started. In response to this, the basis weight detection unit 320 judges the peak value of the received signal level of the ultrasonic wave transmitted at the timing when no paper is present at the detection position 329. Next, the control unit 360 sets the detection mode to the operation sound detection mode M1 at time _T1 . The operation sound detection unit 340 continuously detects the operation sound during a period including, for example, time T11 when the leading edge of the paper _P1 reaches the conveying roller pair 6, and the diagnosis unit 350 diagnoses the presence or absence of an abnormality based on the detected operation sound. The operation sound detection mode M1 can be maintained for a predetermined time length (for example, 200 ms) after time _T11 . The control unit 360 sets the detection mode to the basis weight detection mode M2 at time _T12 . In response to this, the basis weight detection unit 320 determines the peak value of the received signal level of the ultrasonic wave transmitted at the timing when the first detection position of the paper P1 passes the detection position 329. The control unit 360 maintains the basis weight detection mode M2 at time _T13 , and the basis weight detection unit 320 determines the peak value of the received signal level of the ultrasonic wave transmitted at the timing when the second detection position of the paper P1 passes the detection position 329. Next, the control unit 360 sets the detection mode to the operation sound detection mode M1 at time _T2 . The operation sound detection unit 340 continuously detects the operation sound during a period including, for example, time _T21 when the leading edge of the paper P2 to be transported next reaches the transport roller pair 6, and the diagnosis unit 350 diagnoses the presence or absence of an abnormality based on the detected operation sound. Thereafter, the control unit 360 switches the detection mode between the basis weight detection mode M2 and the operation sound detection mode M1 in the same manner according to the transport timing of each paper transported after the paper P2. In an example in which the basis weight is determined based on the peak value of the received signal level of five ultrasonic waves, the basis weight may be determined, for example, at time _T33 . After time _T33 , the basis weight may be updated every five transmissions and receptions of ultrasonic waves. For the sake of simplicity, FIG. 7 shows a case in which the conveying speed of each sheet is not changed based on the detected basis weight. In a case in which the conveying speed of each sheet is changed, the timing of switching the detection mode by the control unit 360 may also change according to the change in the conveying speed.

For example, abnormalities in the image forming unit 1 may include abnormalities in the members involved in feeding paper, such as the feed roller 4, separation roller 5, and conveying roller pair 6. The cause of abnormalities in the feeding-related members is mainly the progression of roller wear. For example, when the electromagnetic clutch (not shown) is turned off and the feed roller 4 is stopped, and the paper is conveyed and pulled out by the downstream conveying roller pair 6, the separation roller 5 vibrates and generates an operating sound. The wear of the roller changes this operating sound, and as the wear progresses, the operating sound can become an abnormal sound. By switching the detection mode according to the first control pattern described above, the operating sound detection mode is set at the timing when these feeding-related members operate, so the condition of the feeding-related members can be reliably diagnosed. In addition, by calculating the attenuation coefficient of ultrasonic waves at multiple points on one sheet of paper, it is possible to reduce errors in basis weight detection caused by variations in the characteristics of the paper. In addition, since the timing between the detection of basis weight (detection of ultrasonic waves) and the detection of operating sounds does not overlap, the receiver 71 can be appropriately shared by the two functions.

Figure 8 is a timing chart showing a second control pattern for switching between the basis weight detection mode and the operation sound detection mode. In the second control pattern, the control unit 360 causes the transmission unit 31 to transmit ultrasonic waves when the center position of the paper (i.e., the second detected position described above) passes through the detection position 329 on the transport path. In addition, the control unit 360 causes the transmission unit 31 to transmit ultrasonic waves when no paper is present at the detection position 329. The control unit 360 causes the operation sound detection unit 340 to detect operation sounds at timings different from these timings.

Specifically, first, the control unit 360 sets the detection mode to the basis weight detection mode M2 at time _T0 before the conveyance of the paper P1 is started. In response to this, the basis weight detection unit 320 judges the peak value of the reception signal level of the ultrasonic wave transmitted at the timing when no paper is present at the detection position 329. Next, the control unit 360 sets the detection mode to the operation sound detection mode M1 at time _T1 . The operation sound detection unit 340 continuously detects the operation sound during a period including, for example, time T11 when the leading edge of the paper P1 reaches the pair of conveying rollers ₆ , and the diagnosis unit 350 diagnoses the presence or absence of an abnormality based on the detected operation sound. The control unit 360 sets the detection mode to the basis weight detection mode M2 at time _T13 . In response to this, the basis weight detection unit 320 judges the peak value of the reception signal level of the ultrasonic wave transmitted at the timing when the second detection position of the paper P1 passes the detection position 329. Next, the control unit 360 sets the detection mode to the operation sound detection mode M1 at time _T2 . The operation sound detection unit 340 continuously detects operation sounds during a period including, for example, time _T21 when the leading edge of the next sheet P2 to be conveyed reaches the pair of conveying rollers 6, and the diagnosis unit 350 diagnoses the presence or absence of an abnormality based on the detected operation sounds. Thereafter, the control unit 360 switches the detection mode between the basis weight detection mode M2 and the operation sound detection mode M1 in the same manner in accordance with the timing of the conveyance of each sheet of paper conveyed after sheet P2.

For example, the abnormality in the image forming unit 1 may include an abnormality in cleaning-related members such as the intermediate transfer belt 17 and the cleaning blade 35. The cause of the abnormality in the cleaning-related members is mainly the change in the sliding resistance between the intermediate transfer belt 17 and the cleaning blade 35 due to wear on the surface of the intermediate transfer belt 17. As described above, the intermediate transfer belt 17 slides against the cleaning blade 35 while rotating and driving, generating an operation sound. The change in the sliding resistance between the intermediate transfer belt 17 and the cleaning blade 35 changes this operation sound, and as wear progresses, the operation sound can become an abnormal sound. However, this abnormal sound may occur at any time during the period in which the image forming operation is performed. Therefore, by switching the detection mode according to the above-mentioned second control pattern, the proportion of the operation sound detection mode can be increased compared to the first control pattern, and the condition of the cleaning-related members can be diagnosed more reliably. Calculating the attenuation coefficient by irradiating ultrasonic waves to the center position of the paper means that the attenuation coefficient is calculated in a state in which the attitude of the paper during transport is most stable, which has the effect of reducing the decrease in the accuracy of basis weight detection. For example, the leading edge of each sheet of paper can be nipped by the secondary transfer roller 19 and the trailing edge by the pair of registration rollers 7 when the center position of the sheet of paper coincides with the detection position 329. In the second control pattern, as in the first control pattern, the timing does not overlap between the detection of the basis weight (ultrasonic detection) and the detection of the operating sound, so the receiver 71 can be appropriately shared between the two functions.

The first and second control patterns described using FIG. 7 and FIG. 8 are merely examples of patterns of switching of the detection mode by the control unit 360. The control unit 360 may switch the detection mode at a timing and frequency different from the timing and frequency shown in the figure. For example, there may be a third control pattern in which the detection mode is always maintained in the operation sound detection mode. Also, there may be a fourth control pattern in which the detection mode is switched depending on the page of the paper being transported. For example, the control unit 360 may set the detection mode to the basis weight detection mode only during the transport of the paper up to the Kth page (e.g., K=1) of the paper stack transported in one job, and thereafter always maintain the operation sound detection mode. Any of these control patterns becomes the default control pattern normally used in the image forming apparatus 100. In this embodiment, the control unit 360 changes the control pattern used to another control pattern when a predetermined condition is satisfied. That is, when a predetermined condition is satisfied, the control unit 360 causes the switching unit 310 to output the received signal from the receiving unit 71 to the signal processing path to the operation sound detection unit 340 at the first timing when the operation sound detection mode would have been set according to the control pattern used. Alternatively, when a predetermined condition is satisfied, the control unit 360 causes the switching unit 310 to output the received signal from the receiving unit 71 to the signal processing path to the basis weight detection unit 320 at the second timing when the operation sound detection mode would have been set according to the control pattern used.

In a first embodiment, the predetermined conditions for changing the control pattern include a first condition that the degree of deterioration of a member that generates an abnormal sound when deteriorated has reached a predetermined level. In a second embodiment, the predetermined conditions include a second condition based on a comparison of the detected variation in basis weight with a threshold value. In a third embodiment, the predetermined conditions include a third condition that a user operation on a cassette 2 that holds recording material before conveyance has been detected. These embodiments are described in more detail below. These conditions may be combined with each other in any manner, and other conditions may be used. For example, if a detection mode is explicitly specified by the user, the specified detection mode may be set.

9 shows three examples of the detailed configuration of the control unit 360. In the first embodiment shown in FIG. 9(A), the control unit 360 includes a life determination unit 361 and a switching control unit 364. The life determination unit 361 monitors the degree of deterioration of a member that generates an abnormal sound when deteriorated among the members constituting the image forming unit 1. The life determination unit 361 then determines whether the degree of deterioration of the monitored member has reached a predetermined level. For example, the number of times the feeding operation has been performed can be an indicator of the degree of deterioration of the feeding-related member. Here, the durability period of the feeding-related member corresponds to 150,000 feeding operations. In this case, the threshold value that triggers the change of the control pattern of the detection mode may be, for example, 120,000 times, which is 80% of 150,000 times. In this case, the life determination unit 361 can determine that the feeding-related member has reached the end of its durability period (i.e., the degree of deterioration of the feeding-related member has reached a predetermined level) when the number of times the feeding operation has been performed reaches 120,000 times. The switching control unit 364 changes the detection mode switching control pattern in response to the life determination unit 361 determining that the degree of deterioration of the monitored component has reached a predetermined level. For example, the switching control unit 364 may set the detection mode to the operation sound detection mode at a timing when the basis weight detection mode would have been set according to the control pattern before the degree of deterioration reached the predetermined level.

FIG. 10 is a timing chart showing an example of the transition of the detection mode when the control pattern is changed according to the first embodiment. Below the timing chart, the control pattern used by the control unit 360 at each time point is shown. In the example shown in FIG. 10, the first control pattern (control pattern C1) of the switching control described with reference to FIG. 7 is used in the initial stage of the image forming operation. That is, the switching control unit 364 sequentially sets the detection mode to the basis weight detection mode at time _T0 , the operation sound detection mode at time _T1 , the basis weight detection mode at time _T12 , and the operation sound detection mode at time _T2 , and so on thereafter. However, it is assumed that the life determination unit 361 determines that the deterioration degree of the monitored member has reached a predetermined level while the paper P3 is being conveyed. In response to this determination, the switching control unit 364 changes the control pattern from the control pattern C1 to the control pattern C3 at time _T4 . In the control pattern C3, the switching control unit 364 always maintains the detection mode in the operation sound detection mode. For example, even at times _T42 and _T43 when the basis weight detection mode would have been set in the case of control pattern C1, the operation sound detection unit 340 detects the operation sound, and the presence or absence of an abnormality is diagnosed by the diagnosis unit 350. In this way, by performing basis weight detection at a high frequency in the early stages and increasing the frequency of operation sound detection after the deterioration of the components has progressed to a certain extent, it is possible to quickly determine the basis weight and set appropriate operating conditions for the image forming operation during periods other than the end of the life of the components.

In the second embodiment shown in FIG. 9B, the control unit 360 includes a variation determination unit 362 and a switching control unit 364. The variation determination unit 362 monitors the variation in basis weight detected by the basis weight detection unit 320 and determines whether the variation in basis weight exceeds or falls below a predetermined threshold. For example, the variation in basis weight may be calculated as the absolute value of the difference between the average value of the past M basis weight detection results and the maximum value among those basis weight detection results. The threshold value to be compared with this variation may be, for example, a value equivalent to 5% of the average value of the basis weight detection results. When the variation determination unit 362 determines that the variation in basis weight falls below the threshold, the switching control unit 364 may set the detection mode to the operation sound detection mode at the timing when the basis weight detection mode would have been set. Conversely, when the variation determination unit 362 determines that the variation in basis weight exceeds a certain threshold, the switching control unit 364 may set the detection mode to the basis weight detection mode at the timing when the operation sound detection mode would have been set. The two thresholds to which the basis weight variation is compared may be different from each other.

FIG. 11 is a timing chart showing an example of the transition of the detection mode when the control pattern is changed according to the second embodiment. In the example shown in FIG. 11, the second control pattern (control pattern C2) of the switching control described with reference to FIG. 8 is used in the middle stage of the image forming operation. For example, the switching control unit 364 sets the detection mode to the operation sound detection mode at time _T6 , and sets the detection mode to the basis weight detection mode at time _T63 . Here, it is assumed that the variation determination unit 362 determines that the variation of the basis weight detection results of the most recent M times detected by the basis weight detection unit 320 exceeds the above-mentioned predetermined threshold value. In response to this determination, the switching control unit 364 changes the control pattern from the control pattern C2 to the control pattern C1 at time _T7 . In the control pattern C1, basis weight detection is performed more frequently than in the control pattern C2. For example, at time _T72 when the operation sound detection mode would have been maintained in the control pattern C2, the switching control unit 364 sets the detection mode to the basis weight detection mode. In this way, by changing the frequency of basis weight detection depending on the variation in basis weight being monitored, it is possible to efficiently secure time for abnormality diagnosis while maintaining the accuracy of basis weight detection at a constant level.

In the third embodiment shown in FIG. 9C, the control unit 360 includes an operation monitoring unit 363 and a switching control unit 364. The operation monitoring unit 363 monitors a sensor signal from the cassette sensor 91. This sensor signal indicates the presence or absence of a user operation on the cassette 2 (e.g., pulling out and inserting the cassette 2). When the operation monitoring unit 363 detects that a user operation on the cassette 2 has occurred based on the sensor signal, the operation monitoring unit 363 records the history of the user operation in memory. When the record in the memory indicates that a user operation on the cassette 2 has occurred during the image forming operation, the switching control unit 364 changes the control pattern of the detection mode. For example, if there is no user operation on the cassette 2, the switching control unit 364 maintains the control pattern used in the previous image forming operation. In contrast, if there is a user operation on the cassette 2, the switching control unit 364 may use a control pattern with a higher proportion of the basis weight detection mode at least in the initial stage of the image forming operation. In this way, by performing basis weight detection as a priority when a user operation is performed on the holding means that holds the recording material, it is possible to reliably capture changes in the type of recording material and set the operating conditions appropriately, while also efficiently securing time for abnormality diagnosis.

<<3. Processing flow>>
<3-1. Detection mode switching process>
(1) First Control Pattern Fig. 12 is a flow chart showing an example of the flow of the detection mode switching process of the first control pattern described with reference to Fig. 7. The process shown in Fig. 12 can be realized, for example, by the CPU 207 executing a computer program loaded from the ROM 208 to the RAM 209. In the following description, the processing steps are abbreviated as S (step).

First, in S1201, the control unit 360 sets the detection mode to the basis weight detection mode. Next, in S1203, the basis weight detection unit 320 causes the transmission unit 31 to transmit ultrasonic waves when no recording material is present at the detection position 329, and determines the peak value of the signal level of the ultrasonic waves received by the reception unit 71.

Next, in S1205, the control unit 360 waits for the timing to start feeding paper. When the timing to start feeding paper arrives, in S1207, the control unit 360 starts feeding the recording material. The recording material is fed from cassette 2 to the conveying path by a feeding-related member, and is conveyed along the conveying path.

Next, in S1209, the control unit 360 sets the detection mode to the operation sound detection mode. Next, in S1211, the control unit 360 waits for the timing to detect the operation sound. When the timing to detect the operation sound arrives, in S1213, the operation sound detection unit 340 detects the operation sound generated in the image forming device 100 by generating sound wave level data based on the sound waves received by the receiving unit 71. Next, in S1215, the diagnosis unit 350 determines whether an abnormality has occurred or there is a sign of an abnormality in the image forming device 100 based on the sound wave level data generated by the operation sound detection unit 340. If it is determined that an abnormality has occurred or there is a sign of an abnormality in the image forming device 100, in S1217, the diagnosis unit 350 notifies the user of the occurrence of the abnormality or the sign of an abnormality (for example, by displaying abnormality-related information on a screen or transmitting it to another device). If it is determined that no abnormality has occurred and there are no signs of an abnormality occurring, S1217 is skipped. Then, in S1219, if the timing for detecting the basis weight has arrived, the process proceeds to S1221. If the timing for detecting the basis weight has not arrived, the process returns to S1213, and the detection and diagnosis of the operating sound can be repeated.

In S1221, the control unit 360 sets the detection mode to the basis weight detection mode. Next, in S1223, the basis weight detection unit 320 causes the transmission unit 31 to transmit ultrasonic waves when the first detectable position of the recording material passes the detection position 329, and determines the peak value of the signal level of the ultrasonic waves received by the reception unit 71. Next, in S1225, the basis weight detection unit 320 waits for the second detectable position of the recording material to pass the detection position 329. Next, in S1227, the basis weight detection unit 320 causes the transmission unit 31 to transmit ultrasonic waves when the second detectable position of the recording material passes the detection position 329, and determines the peak value of the signal level of the ultrasonic waves received by the reception unit 71.

Next, in S1229, the basis weight detection unit 320 determines whether N peak value determinations (e.g., N=5) have been performed at the timing when the recording material is present at the detection position 329. If N peak value determinations have been performed, then in S1231 the basis weight detection unit 320 detects the basis weight of the recording material based on the peak values of the N ultrasonic level signals and the peak value determined in S1203. Next, in S1233, the condition setting unit 330 sets or changes the operating conditions of the image forming operation in the image forming apparatus 100 based on the basis weight of the recording material detected by the basis weight detection unit 320. If N peak value determinations have not been performed, S1231 and S1233 are skipped.

Next, in S1235, the control unit 360 determines whether to end the image forming operation. For example, when image formation on the number of sheets of recording material specified by the print job is completed, the control unit 360 determines that the image forming operation is to be ended. If the image forming operation is not to be ended, the process returns to S1205, and the above-described process is repeated for the next recording material.

Although not shown in FIG. 12, while the above-mentioned process is being performed, the image forming unit 1 performs an image forming operation. In the image forming operation, for example, feeding-related members such as the feeding roller 4, the separation roller 5, and the conveying roller pair 6 feed the recording material to the conveying path. The primary transfer roller 16 transfers the electrostatic latent image formed on the photoconductor 11 to the intermediate transfer belt 17, and the secondary transfer roller 19 transfers the developer image on the intermediate transfer belt 17 to the recording material. The cleaning blade 35 collects the developer remaining on the intermediate transfer belt 17 to the cleaning unit 36. The fixing device 21 pressurizes and heats the recording material to fix the developer image to the recording material. After that, the recording material is discharged, for example, to a discharge tray by the discharge roller pair 22. Operation sounds generated during these operations can be detected by the operation sound detection unit 340 while the detection mode is set to the operation sound detection mode.

(2) Second Control Pattern Fig. 13 is a flowchart showing an example of the flow of the detection mode switching process of the second control pattern described with reference to Fig. 8. The process shown in Fig. 13 can be realized, for example, by the CPU 207 executing a computer program loaded from the ROM 208 to the RAM 209.

First, in S1301, the control unit 360 sets the detection mode to the basis weight detection mode. Next, in S1303, the basis weight detection unit 320 causes the transmission unit 31 to transmit ultrasonic waves when no recording material is present at the detection position 329, and determines the peak value of the signal level of the ultrasonic waves received by the reception unit 71.

Next, in S1305, the control unit 360 waits for the timing to start feeding paper. When the timing to start feeding paper arrives, in S1307, the control unit 360 starts feeding the recording material. The recording material is fed from cassette 2 to the conveying path by a feeding-related member, and is conveyed along the conveying path.

Next, in S1309, the control unit 360 sets the detection mode to the operation sound detection mode. Next, in S1311, the control unit 360 waits for the timing to detect the operation sound. When the timing to detect the operation sound arrives, in S1313, the operation sound detection unit 340 detects the operation sound generated in the image forming device 100 by generating sound wave level data based on the sound waves received by the receiving unit 71. Next, in S1315, the diagnosis unit 350 determines whether an abnormality has occurred or there is a sign of an abnormality in the image forming device 100 based on the sound wave level data generated by the operation sound detection unit 340. If it is determined that an abnormality has occurred or there is a sign of an abnormality in the image forming device 100, in S1317, the diagnosis unit 350 notifies the user of the occurrence of the abnormality or the sign of an abnormality. If it is determined that no abnormality has occurred and there is no sign of an abnormality, S1317 is skipped. Thereafter, in S1319, if the timing for detecting the basis weight has arrived, the process proceeds to S1321. If the timing for detecting the basis weight has not arrived, the process returns to S1313, and the detection and diagnosis of the operating sound may be repeated.

In S1321, the control unit 360 sets the detection mode to the basis weight detection mode. Next, in S1323, the basis weight detection unit 320 causes the transmission unit 31 to transmit ultrasonic waves when the second detection position of the recording material passes the detection position 329, and determines the peak value of the signal level of the ultrasonic waves received by the reception unit 71.

Next, in S1329, the basis weight detection unit 320 determines whether N peak value determinations have been performed at the timing when the recording material is present at the detection position 329. If N peak value determinations have been performed, then in S1331, the basis weight detection unit 320 detects the basis weight of the recording material based on the peak values of the N ultrasonic level signals and the peak value determined in S1303. Next, in S1333, the condition setting unit 330 sets or changes the operating conditions of the image forming operation in the image forming apparatus 100 based on the basis weight of the recording material detected by the basis weight detection unit 320. If N peak value determinations have not been performed, S1331 and S1333 are skipped.

Next, in S1335, the control unit 360 determines whether to end the image forming operation. For example, when image formation on the number of recording materials specified by the print job has been completed, the control unit 360 determines that the image forming operation is to be completed. If the image forming operation is not to be completed, the process returns to S1305, and the above-described process is repeated for the next recording material. While these processes are being performed, the image forming operation is performed by the image forming unit 1. Operation sounds generated during the image forming operation can be detected by the operation sound detection unit 340 while the detection mode is set to the operation sound detection mode.

<3-2. Changing the control pattern>
14 to 16 respectively show examples of the process flow for changing the control pattern according to the first, second, and third embodiments described above. Each process can be realized, for example, by the CPU 207 executing a computer program loaded from the ROM 208 to the RAM 209.

(1) First embodiment First, in S1401, the control unit 360 starts an image forming operation in response to, for example, receiving a print job from an external host computer. In S1403, the switching control unit 364 starts control of switching the detection mode between the basis weight detection mode and the operation sound detection mode in a certain control pattern (for example, the first control pattern described above). While the image forming operation is being performed, in S1405, the life determination unit 361 monitors the degree of deterioration of members (for example, feeding-related members and cleaning-related members) that generate abnormal sounds when deteriorated among members involved in the image forming operation. In S1407, the life determination unit 361 determines whether the degree of deterioration of the monitored members has reached a predetermined level. If it is determined that the degree of deterioration of the monitored members has reached the predetermined level, the switching control unit 364 changes the control pattern in use to another control pattern (for example, the second or third control pattern described above) that has a higher frequency of operation sound detection. If the degree of deterioration of the monitored member has not reached the predetermined level, S1409 is skipped. Next, in S1411, control unit 360 determines whether to end the image forming operation. If it is determined that the image forming operation is to be ended, control unit 360 ends monitoring by life determination unit 361. If the image forming operation is not to be ended, the process returns to S1405, and life determination unit 361 continues to monitor the degree of deterioration of the member.

In addition, in the basis weight detection mode M2, ultrasonic waves are transmitted from the transmitter 31 toward the conveying path. Therefore, increasing the frequency of basis weight detection corresponds to setting the length of the period during which ultrasonic waves are transmitted from the transmitter 31 (hereinafter referred to as the ultrasonic transmission period) to be longer, and decreasing the frequency of basis weight detection corresponds to setting the length of the ultrasonic transmission period to be shorter. Therefore, as a first application example of the first embodiment, when the degree of deterioration of the member has not reached a predetermined level, the switching control unit 364 sets the length of the ultrasonic transmission period to a predetermined length. Then, when the degree of deterioration of the member has reached the predetermined level, the switching control unit 364 may set the length of the ultrasonic transmission period to be shorter than the above-mentioned predetermined length.

Also, as a second application example of the first embodiment, the switching control unit 364 may be able to change the ratio of the length of the period of the basis weight detection mode M2 (hereinafter referred to as the basis weight detection period) to the length of the period of the operation sound detection mode M1 (hereinafter referred to as the operation sound detection period) during the period in which one sheet of recording material P passes through the detection position 329 between the transmitting unit 31 and the receiving unit 71. That is, when the deterioration degree of the member has not reached a predetermined level, the switching control unit 364 sets the ratio of the length of the basis weight detection period to a predetermined value. Then, when the deterioration degree of the member has reached a predetermined level, the switching control unit 364 may set the ratio to a value smaller than the predetermined value. As an example, the ratio may be reset (i.e., changed) to a value less than 1 so that the length of the operation sound detection period is longer than the length of the basis weight detection period. The length of the basis weight detection period after the deterioration degree of the member has reached a predetermined level may be zero, as shown in the control pattern C3 of FIG. 10.

(2) Second Example First, in S1501, the control unit 360 starts an image forming operation in response to, for example, receiving a print job from an external host computer. In S1503, the switching control unit 364 starts control of switching the detection mode between the basis weight detection mode and the operation sound detection mode, for example, in the first control pattern. While the image forming operation is being performed, the basis weight detection unit 320 detects the basis weight of the recording material. In S1505, the variation determination unit 362 calculates the variation in basis weight detected by the basis weight detection unit 320. Next, in S1507 and S1509, the basis weight detection unit 320 compares the calculated basis weight variation with a threshold value. For example, if the current control pattern is the first control pattern and the basis weight variation is below the predetermined threshold value, the process proceeds to S1511. Also, if the current control pattern is the second control pattern and the basis weight variation is above the predetermined threshold value, the process proceeds to S1513. In S1511, the switching control unit 364 changes the control pattern from the first control pattern to the second control pattern, which has a lower frequency of basis weight detection. In S1513, the switching control unit 364 changes the control pattern from the second control pattern to the first control pattern. If neither the condition of S1507 nor S1509 is satisfied, both S1511 and S1513 are skipped. Next, in S1515, the control unit 360 determines whether to end the image forming operation. If it is determined that the image forming operation is to be ended, the control unit 360 causes the variation determination unit 362 to end the calculation of the basis weight variation. If the image forming operation is not ended, the process returns to S1505, and monitoring of the basis weight variation continues.

As described in relation to the first embodiment, increasing the frequency of basis weight detection corresponds to setting the length of the ultrasonic transmission period to be longer, and decreasing the frequency of basis weight detection corresponds to setting the length of the ultrasonic transmission period to be shorter. Therefore, as a first application example of the second embodiment, the switching control unit 364 may set the length of the ultrasonic transmission period to a predetermined length when the variation in basis weight is below a threshold, and may set the length of the ultrasonic transmission period to be longer than the predetermined length when the variation in basis weight is above the threshold.

Also, as a second application example of the second embodiment, the switching control unit 364 may be able to change the ratio of the length of the basis weight detection period to the length of the operation sound detection period within the period in which one sheet of recording material P passes through the detection position 329 between the transmitting unit 31 and the receiving unit 71. In other words, the switching control unit 364 may set the ratio of the length of the basis weight detection period to a predetermined value when the variation in basis weight is below a threshold value, and may set the ratio to a value greater than the predetermined value when the variation in basis weight exceeds the threshold value. As an example, when the variation in basis weight exceeds the threshold value, the ratio may be set to a value greater than 1 so that the length of the basis weight detection period is longer than the length of the operation sound detection period.

(3) Third embodiment First, in S1601, the operation monitoring unit 363 monitors a user operation on cassette 2 based on a sensor signal from the cassette sensor 91. When the operation monitoring unit 363 detects that a user operation has been performed on cassette 2, in S1603, the operation monitoring unit 363 records a history of the user operation in memory. Meanwhile, in S1605, the control unit 360 determines whether an image forming operation should be started. For example, when a print job is received from an external host computer, the control unit 360 determines that an image forming operation should be started, and the process proceeds to S1607.

In S1607, the control unit 360 starts the image forming operation. Next, in S1609, the switching control unit 364 determines whether there is an operation history of the cassette 2 recorded by the operation monitoring unit 363. If there is an operation history of the cassette 2, the switching control unit 364 starts the switching control of the detection mode between the basis weight detection mode and the operation sound detection mode in a control pattern with a higher frequency of basis weight detection (for example, the first control pattern described above). Next, the switching control unit 364 erases the record of the operation history of the cassette 2. On the other hand, if there is no operation history of the cassette 2, the switching control unit 364 maintains the control pattern used in the operation up to that point. Next, in S1617, the control unit 360 determines whether to end the image forming operation. If the image forming operation is not ended, in S1619, the switching control unit 364 determines whether to change the control pattern being used according to a predetermined condition. The predetermined condition here may be any condition, such as a condition based on the degree of deterioration of the member or a condition based on the variation in basis weight. If the specified conditions are met, the switching control unit 364 changes the control pattern in use to another control pattern in S1621. Processing then returns to S1609. The control pattern changed in S1609 can continue to be used unless a new user operation on cassette 2 is detected.

As described in relation to the first and second embodiments, increasing the frequency of basis weight detection corresponds to setting the length of the ultrasonic transmission period to be longer, and decreasing the frequency of basis weight detection corresponds to setting the length of the ultrasonic transmission period to be shorter. Thus, as a first application example of the third embodiment, the switching control unit 364 sets the length of the ultrasonic transmission period to a predetermined length when a user operation on the cassette 2 is not detected. Then, when a user operation on the cassette 2 is detected, the switching control unit 364 may set the length of the ultrasonic transmission period to be longer than the above-mentioned predetermined length. After the basis weight is detected with a longer ultrasonic transmission period in response to the user operation, the switching control unit 364 may return the length of the ultrasonic transmission period to the above-mentioned predetermined length.

Also, as a second application example of the third embodiment, the switching control unit 364 may be able to change the ratio of the length of the basis weight detection period to the length of the operation sound detection period during the period in which one sheet of recording material P passes through the detection position 329 between the transmitting unit 31 and the receiving unit 71. That is, the switching control unit 364 may set the ratio of the basis weight detection period to a predetermined value when a user operation on the cassette 2 is not detected, and set the ratio to a value greater than the predetermined value when a user operation on the cassette 2 is detected. As an example, when a user operation on the cassette 2 is detected, the ratio may be set to a value greater than 1 so that the length of the basis weight detection period is longer than the length of the operation sound detection period. The switching control unit 364 may return the length of the ultrasonic transmission period to the predetermined value after the basis weight is detected in a state in which the ratio of the ultrasonic transmission period is set to a larger value in response to the user operation.

<<4. Modifications>>
Up to this point, the example in which the detection mode is switched in one of a plurality of control patterns designed in advance has been mainly described. However, the control pattern may be dynamically or adaptively determined. For example, in the first modified example, when a member (e.g., a feeding-related member) that generates an operation sound only at a limited timing is the target of abnormality diagnosis, the control unit 360 may preferentially set the operation sound detection mode in a period including the timing. In this case, the control unit 360 may set the basis weight detection mode or the operation sound detection mode in the remaining period. In the second modified example, when a member that is the target of abnormality diagnosis may generate an operation sound at any time, the control unit 360 may preferentially set the basis weight detection mode in a period suitable for basis weight detection. In this case, the control unit 360 may set the basis weight detection mode or the operation sound detection mode in the remaining period. The operation sound detection mode may be set only when a sufficiently long detection time (e.g., 200 ms) can be secured. In any modified example, the control unit 360 may change the control pattern currently in use to another control pattern when the predetermined condition described above is satisfied.

In the above-described embodiment, an example has been described in which the diagnostic unit 350 of the image forming device 100 diagnoses the state of the image forming unit 1 based on the detected operating sound. However, instead of the diagnosis based on the operating sound being performed in the image forming device 100, the diagnosis may be performed in another device that receives data related to the operating sound from the image forming device 100. Also, the image forming device 100 or another device may play back the operating sound or present data related to the operating sound, allowing manual diagnosis by a user or service person.

<<5. Summary>>
Up to this point, the embodiment of the present disclosure has been described in detail with reference to FIGS. 1 to 16. In the above-described embodiment, the image forming apparatus has a first detection means for detecting an operation sound based on sound waves and a second detection means for detecting the basis weight of a recording material based on ultrasonic waves, and a receiving means for receiving sound waves or ultrasonic waves is shared by the first detection means and the second detection means. The image forming apparatus also has a switching means for switching an output destination of a received signal from the receiving means between a first path to the first detection means and a second path to the second detection means. In a certain control pattern, the switching means outputs a received signal from the receiving means to the first path at a first timing, and outputs a received signal from the receiving means to the second path at a second timing different from the first timing. When a predetermined condition is satisfied, the control pattern is changed, and the switching means outputs a received signal from the receiving means to the second path at the first timing, or outputs a received signal from the receiving means to the first path at the second timing. According to this configuration, the timing when the receiving means is used by the first detection means to detect the operation sound does not overlap with the timing when the receiving means is used by the second detection means to detect the basis weight. Therefore, the operation sound and basis weight can be appropriately detected while avoiding the increase in size of the device, the increase in the number of parts, and the increase in cost by sharing the receiving means. In addition, when the predetermined condition is satisfied, the control pattern of the detection mode switching control is changed, so that the frequency of detection of the operation sound and the basis weight can be appropriately maintained in accordance with the change over time of the situation of the image forming device.

In one embodiment, the predetermined condition may include a first condition that the degree of deterioration of a member that generates abnormal sounds when deteriorated has reached a predetermined level. By maintaining a relatively high frequency of basis weight detection until the first condition is met, the basis weight can be determined quickly and operating conditions suitable for, for example, the type of recording material can be set. Furthermore, by increasing the frequency of operation sound detection when the first condition is met, it is possible to more reliably detect the occurrence of an abnormality in the device at the end of the life of the member, or to detect signs of an abnormality earlier and take the necessary measures.

In one embodiment, the predetermined condition may include a second condition based on a comparison of the variation in basis weight detected by the second detection means with a threshold value. For example, when the variation in basis weight is below the threshold value, it is considered that the accuracy of basis weight detection will meet a certain level even if the frequency of basis weight detection is reduced, so it is beneficial to increase the frequency of detection of operational sounds to increase the certainty of detecting the occurrence of an abnormality or a sign of an abnormality. Conversely, when the variation in basis weight is above the threshold value, the accuracy of basis weight detection can be maintained at a certain level by increasing the frequency of basis weight detection.

In one embodiment, the predetermined conditions may include a third condition that a user operation on the holding means that holds the recording material before conveyance is detected. If the third condition is not met, it is considered that the type of recording material held by the holding means has not changed, and the frequency of basis weight detection can be kept relatively low by reusing the previous basis weight detection result. In addition, by increasing the frequency of basis weight detection when the third condition is met, it is possible to quickly determine the basis weight and quickly determine the type of recording material that may have been changed.

In the above-described embodiment, the image forming apparatus further includes a setting unit that sets operating conditions for the image forming operation in the image forming apparatus based on the basis weight detected by the second detection unit. In this case, operating conditions suitable for the type of recording material used can be automatically set based on the basis weight detected at an appropriate frequency.

In the above-described embodiment, the image forming device further includes an abnormality diagnosis means for determining whether an abnormality has occurred or a sign of an abnormality has occurred in the image forming device based on the operation sound detected by the first detection means. In this case, during the efficiently secured period for abnormality diagnosis, the image forming device itself can recognize the occurrence of an abnormality or a sign of an abnormality and quickly notify the user.

The change in the control pattern described above can also be considered as a change in the detection period for detecting the basis weight. That is, when a certain control pattern is effective, the transmission means is controlled to transmit ultrasonic waves during a detection period corresponding to at least a part of the period during which the recording material passes through the section between the transmission means for transmitting ultrasonic waves and the reception means. During this detection period, the second detection means detects the basis weight of the recording material based on a signal related to ultrasonic waves. The control pattern is changed to another control pattern when the predetermined condition is satisfied. Accordingly, the length of the detection period can be changed to a longer or shorter period. As a result, the basis weight can be detected by the second detection means at a timing when the operation sound would have been detected by the first detection means, or the operation sound can be detected by the first detection means at a timing when the basis weight would have been detected by the second detection means.

<<6. Other embodiments>>
The above-described embodiment can also be realized in the form of a process in which a program for realizing one or more functions is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. Also, the embodiment can be realized by a circuit (e.g., ASIC) for realizing one or more functions.

The invention is not limited to the above-described embodiment, and various modifications and variations are possible without departing from the spirit and scope of the invention. Therefore, the following claims are appended to disclose the scope of the invention.

31: Transmitter (transmitter means), 71: Receiver (receiving means), 100: Image forming device, 205: Operation/display unit (display means), 206: Communication I/F (communication means), 310: Switching unit (switching means), 320: Basis weight detection unit (second detection means), 312: Analog filter (filtering means), 313: Amplifier (second amplifier means), 315: Amplifier (first amplifier means), 330: Condition setting unit (setting means), 340: Operation sound detection unit (first detection means), 350: Diagnosis unit (abnormality diagnosis means), 360: Control unit (control means), P, P1 to P9: Recording material (paper)

Claims (16)

An image forming apparatus for forming an image on a recording material,
a transmitting means for transmitting ultrasonic waves toward a conveying path along which the recording material is conveyed;
a receiving unit for receiving the sound wave generated in the image forming apparatus or the ultrasonic wave transmitted by the transmitting unit ;
a control means for switching from the first operation to the second operation when a predetermined condition is satisfied;
Equipped with
The first operation is to detect the basis weight of the recording material based on the ultrasonic waves received by the receiving means,
The second operation is for acquiring information of the sound wave received by the receiving means.
Image forming device. 2. The image forming apparatus according to claim 1,
The control means monitors the degree of deterioration of a member that generates an abnormal sound when deteriorated,
The predetermined condition is that the degree of deterioration has reached a predetermined level.
Image forming device. 3. The image forming apparatus according to claim 1,
a setting unit for setting operating conditions for an image forming operation in the image forming apparatus based on the detected basis weight;
The image forming apparatus further comprises: 4. An image forming apparatus according to claim 3 , wherein the operating conditions include one or more of a conveying speed of the recording material, an applied bias for transferring toner to the recording material, and a heating temperature for fixing the toner to the recording material. 5. The image forming apparatus according to claim 1,
an abnormality diagnosis unit that determines whether an abnormality has occurred or a sign of an abnormality has occurred in the image forming apparatus based on the information of the sound waves ;
The image forming apparatus further comprises: 6. The image forming apparatus according to claim 5 ,
a display means for displaying information indicating a result of the determination when the abnormality diagnosis means determines that the abnormality has occurred or that there is a sign of the occurrence of the abnormality;
The image forming apparatus further comprises: 7. The image forming apparatus according to claim 5 ,
a communication means for transmitting information indicating a result of the determination to another device when the abnormality diagnosis means determines that the abnormality has occurred or that there is a sign of the occurrence of the abnormality;
The image forming apparatus further comprises: 8. The image forming apparatus according to claim 1,
The control means monitors the detected variation in basis weight,
the predetermined condition includes that the variation in basis weight is smaller than a threshold value.
Image forming device. An image forming apparatus for forming an image on a recording material,
a transmitting means for transmitting ultrasonic waves toward a conveying path along which the recording material is conveyed;
a receiving unit for receiving the sound wave generated in the image forming apparatus or the ultrasonic wave transmitted by the transmitting unit ;
a control means for switching from the second operation to the first operation when a predetermined condition is satisfied;
Equipped with
The first operation is to detect the basis weight of the recording material based on the ultrasonic waves received by the receiving means,
The second operation is for acquiring information of the sound wave received by the receiving means.
Image forming device. 10. The image forming apparatus according to claim 9 ,
the control unit monitors a user operation on a holding unit that holds the recording material before it is conveyed;
the predetermined condition being that the user operation on the holding means has been detected;
Image forming device. 11. The image forming apparatus according to claim 9 ,
a setting unit for setting operating conditions for an image forming operation in the image forming apparatus based on the detected basis weight;
The image forming apparatus further comprises: 12. An image forming apparatus according to claim 11 , wherein the operating conditions include one or more of a conveying speed of the recording material, an applied bias for transferring toner to the recording material, and a heating temperature for fixing the toner to the recording material. 13. The image forming apparatus according to claim 9 ,
an abnormality diagnosis unit that determines whether an abnormality has occurred or a sign of an abnormality has occurred in the image forming apparatus based on the information of the sound waves ;
The image forming apparatus further comprises: 14. The image forming apparatus according to claim 13 ,
a display means for displaying information indicating a result of the determination when the abnormality diagnosis means determines that the abnormality has occurred or that there is a sign of the occurrence of the abnormality;
The image forming apparatus further comprises: 15. The image forming apparatus according to claim 13 ,
a communication means for transmitting information indicating a result of the determination to another device when the abnormality diagnosis means determines that the abnormality has occurred or that there is a sign of the occurrence of the abnormality;
The image forming apparatus further comprises: 16. The image forming apparatus according to claim 9,
The control means monitors the detected variation in basis weight,
the predetermined condition includes that the variation in basis weight is greater than a threshold value.
Image forming device.

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