JP2014205558A - Image formation device, and method and program for controlling the same - Google Patents

Abstract

An image forming apparatus capable of accurately determining the state of a recording medium in a conveyance path, a control method therefor, and a program are provided even when disturbance noise occurs. An image forming apparatus includes: a spectrum indicating a frequency spectrum of sound data recorded in a storage unit when a jam is detected by a jam detection unit while a recording medium is being conveyed along a conveyance path; When the generation of disturbance noise is detected from the time when it is converted to data and the recording medium is transported until the jam is detected, the frequency area where the disturbance noise exists is excluded from the predetermined frequency area. The state of the recording medium is determined from the spectrum data in the frequency domain. [Selection] Figure 6

Description

  The present invention relates to an image forming apparatus, a control method therefor, and a program.

  In order to detect a jam of the conveyed paper at an early stage, a technique has been proposed in which a sound sensor is provided in the image forming apparatus and a paper jam is determined from the detection result of the sound sensor that is conveying the paper. (For example, refer to Patent Document 1).

  The signal input to the sound sensor is AD converted and input to the determination circuit. Inside the determination circuit, the sound spectrum is analyzed according to the paper, and it is determined whether or not a paper jam has occurred based on the intensity of the focused frequency band according to the type of paper.

  Compared with jam detection using an optical sensor, jam can be detected at an early stage, so that damage that occurs in the image forming apparatus can be reduced without the paper being continuously conveyed.

Japanese Patent Laid-Open No. 2001-302021

  However, various sounds are generated from the main body of the image forming apparatus during conveyance of the sheet. For example, the driving sound of a motor, a gear, etc., the rotation sound of a fan, etc. correspond to it.

  In the technique disclosed in Patent Document 1, a method is described in which attention is paid to the sound spectrum of the sound generated by the paper, but the sound spectrum of the sound generated from the paper overlaps with the sound generated by the image forming apparatus itself. May cause false positives.

  In addition, in order to improve the operability of the image forming apparatus, there is an image forming apparatus that allows a user to perform some cover opening / closing operations even when the image forming apparatus is in operation. For example, there is an image forming apparatus that can replenish a sheet by opening and closing a cover of another sheet feeding unit even when the sheet is conveyed from a specific sheet feeding unit.

  There is also an image forming apparatus provided with an output paper stacker that can replenish recording ink and toner even during printing, or can take out an output medium without switching the tray of the paper discharge unit and stopping the image forming apparatus.

  In such an image forming apparatus, when the sound spectrum of the sound generated by the user operation and the sound spectrum of the sound generated from the paper overlap, it is conceivable that the paper jam is erroneously detected.

  Further, a sound from the external environment where the image forming apparatus is installed can be considered as a cause of erroneous detection. In the case of an image forming apparatus placed in an environment with external noise, it may overlap with the sound spectrum of the sound generated from the paper, and there may be a case where the paper jam cannot be correctly determined.

  When such a false detection occurs, there is a problem that parts such as a gear and a motor are damaged in an attempt to forcibly transport the paper even though the paper is jammed. It is also conceivable that a paper that is not jammed is determined as a paper jam and the user manually removes it.

  An object of the present invention is to provide an image forming apparatus that can accurately determine the state of a recording medium in a conveyance path, a control method thereof, and a program even when disturbance noise occurs.

  In order to achieve the above object, an image forming apparatus according to claim 1 is an image forming apparatus including a conveyance path for conveying a recording medium, and the recording medium is conveyed when the recording medium is conveyed along the conveyance path. Disturbance sound detection means for detecting the occurrence of disturbance sound other than sound generated by the recording medium, jam detection means for detecting jamming in the transport path, and when the recording medium is transported in the transport path, A sound collecting means for collecting sound generated by the recording medium, a storage means for storing sound data indicating the sound collected by the sound collecting means, and the recording medium being conveyed through the conveyance path, When the jam is detected by the jam detection means, the sound data stored in the storage unit is converted into spectrum data indicating a frequency spectrum; and the recording medium is conveyed, and then the jam is detected. If a disturbance sound is detected by the disturbance sound detection means before the jam is detected by the knowledge means, the frequency range is determined by excluding the frequency area where the disturbance sound exists from a predetermined frequency area. Discriminating means for discriminating the state of the recording medium from the spectrum data.

  According to the present invention, it is possible to provide an image forming apparatus that can accurately determine the state of a recording medium in a conveyance path, a control method thereof, and a program even when disturbance noise occurs.

1 is a diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a schematic configuration of a control unit of the image forming apparatus in FIG. 1. It is a figure which shows the external appearance of the input part in FIG. 2, and a display part. FIG. 3 is a diagram for explaining jam detection using a pre-registration conveyance sensor and a paper conveyance sensor in FIG. 1. It is a figure for demonstrating a stay jam and a delay jam. 3 is a flowchart illustrating a procedure of print processing executed by a control unit in FIG. 2. FIG. 10 is a diagram illustrating an example of automatic paper discharge processing when a stay or delay jam occurs in the vicinity of the fixing device. (A) shows an example of the frequency of sound generated when the cover is opened and closed, (B) shows data of the frequency spectrum of the sound, and (C) is used to determine whether or not the paper is buckled. Paper state determination data is shown, and (D) shows a comparison result. It is a figure which shows an example of generation | occurrence | production spectrum data, paper state discrimination | determination data, and a matching point. It is a flowchart which shows the procedure of the sound analysis process of step S506 in FIG. It is a flowchart which shows the procedure of the comparison process in step S702 of FIG. It is a flowchart which shows the procedure of the conveyance availability determination process of step S507 in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus 300 according to an embodiment of the present invention.

  In FIG. 1, the image forming apparatus 300 includes a document feeder 500, an image reader 400, and a printer 119.

  The document feeder 500 conveys the set originals one by one from the top page in order from the left to the right through the curved conveyance path, and then ejects them to the paper ejection tray.

  At this time, the reader scanner unit is held at a predetermined position, and the document is read by passing the document from the left to the right through the reader scanner unit.

  When the document passes, the light of the lamp of the reader scanner unit is irradiated onto the document, and the reflected light from the document is guided to the image sensor via the mirror. It is also possible to read the original by moving the reader scanner unit from left to right after stopping the original after it has been conveyed onto the platen glass by the original feeding device 500.

  The document image read by the image reader 400 is subjected to image processing and sent to the exposure control units 103y, 103m, 103c, and 103k.

  The toner supply units 101y, 101m, 101c, and 101k supply toner to the developing units 102y, 102m, 102c, and 102k. The laser light output by the exposure control unit is applied to the photosensitive drums 10y, 10m, 10c, and 10k, and electrostatic latent images are formed on the photosensitive drums 10y, 10m, 10c, and 10k.

  The electrostatic latent images formed on the photosensitive drums 10y, 10m, 10c, and 10k are developed by the developing units 102y, 102m, 102c, and 102k. After being transferred to the intermediate transfer belt 104 by the primary transfer units 105y, 105m, 105c, and 105k, the toner is fed from any of the cassettes 109 and 110, the manual paper feed unit 111, and the double-sided conveyance path 112. The image is transferred to a sheet (recording medium) by the secondary transfer unit 106.

  The sheet onto which the toner has been transferred is subjected to toner fixing processing by a fixing device 170 and fixing rollers 113 and 114. The paper that has passed through the fixing device 170 is once guided to the conveyance path 122 by the reverse flapper 121, and after the rear end of the paper has passed through the reverse flapper 121, the paper is switched back and guided to the discharge roller 118 by the reverse flapper 121.

  As a result, the surface onto which the toner has been transferred is discharged from the image forming apparatus 300 by the discharge roller 118 with the face down. When performing duplex printing, the paper that has passed through the fixing device 170 is once guided to the conveyance path 122 by the reverse flapper 121 and is switched back after the trailing edge of the paper passes through the double-sided flapper 123. 123 is guided to the duplex conveyance path 112. Accordingly, it is possible to perform a paper refeeding operation so as to perform image formation on the second side.

  In addition, the image forming apparatus 300 according to the present embodiment includes a pre-registration conveyance sensor 160 and a paper conveyance sensor 171, which detect that the paper is being conveyed correctly and that a paper jam has occurred.

  The image forming apparatus 300 includes a sound collecting device 310, and the sound collecting device 310 corresponds to a sound collecting unit that collects sound generated by the paper when the paper is being conveyed on the conveyance path.

  Among the codes described above, the codes assigned with c, m, y, and k are used with the codes from which c, m, y, and k are removed unless it is necessary to distinguish them.

  FIG. 2 is a diagram illustrating a schematic configuration of the control unit 200 of the image forming apparatus 300 in FIG.

  2, the control unit 200 includes a CPU 201, a ROM 202, a RAM 203, a display unit 206, an input unit 205, and an external interface 204.

  The control unit 200 is connected to the sound collecting device 310, the motor 330, the open / close sensor 320, the image reader 400, the printer 119, the pre-registration transport sensor 160, and the paper transport sensor 171.

  The CPU 201 controls the entire image forming apparatus 300 and executes processing of a flowchart described later. The ROM 202 stores a program executed by the CPU 201, paper state determination data described later, and the like.

  A RAM 203 serving as a storage unit is used as a work area necessary for the CPU 201 to control the image forming apparatus 300.

  The RAM 203 also stores an image obtained by the image reader 400 reading a document, an image obtained from the outside by the external interface 204, and the like. The RAM 203 is also used as a work area for performing image processing on images obtained from the image reader 400 and the external interface 204 during image processing.

  An input unit 205 is an operation unit for the user to instruct setting of the image forming apparatus 300 and execution of processing. A print job can be instructed by the input unit 205, but it is also possible to execute a print job via the external interface 204.

  The external interface 204 is connected to a network using a protocol such as TCP / IP, and can receive a print job execution instruction from a computer connected to the network, or can transmit information about the image forming apparatus 300 to the computer.

  A motor 330 connected to the control unit 200 is a motor for driving each unit in order to carry a sheet. Since there are two open / close sensors 320, each will be described.

  First. In image forming apparatus 300 according to the present exemplary embodiment, a user can attach or remove a toner cartridge to / from toner replenishing unit 101. Therefore, the cover part which a user opens and closes is provided.

  One of the open / close sensors 320 is a sensor that detects the opening / closing of a cover portion that is opened / closed to attach or remove the toner cartridge, and the detection content is notified to the control unit 200.

  Further, in the image forming apparatus 300, the cassettes 109 and 110 can be taken in and out by operating the cover unit so that the user supplies paper to the cassettes 109 and 110. The other one of the opening / closing sensors 320 is a sensor that detects opening / closing of a cover portion that is opened and closed to supply paper to the cassettes 109 and 110, and the detected content is notified to the control unit 200. The open / close sensor 320 corresponds to a disturbance sound detection unit that detects the generation of a disturbance sound other than the sound generated by the sheet when the sheet is conveyed along the conveyance path. Since the open / close sensor 320 does not directly detect disturbance noise but generates sound by opening and closing the cover, being able to detect opening and closing can detect occurrence of disturbance noise.

  Note that the sound generated when the user performs a physical operation on the image forming apparatus 300, such as an operation of pressing a key of the input unit 205, is not limited to opening and closing the cover, and may be a disturbance sound.

  FIG. 3 is a diagram showing the appearance of the input unit 205 and the display unit 206 in FIG.

  In FIG. 3, a display unit 206 is a touch panel and can be operated by a user. For example, a soft key is displayed on the display unit 206, and it is possible to set an image forming operation such as paper selection, single-sided / double-sided printing instruction, color mode, and monochrome mode color mode.

  A start key 1106 is a key pressed by the user to start a printing operation, for example.

  A numeric keypad 1103 is a key for enabling a user to input numerical values. The numerical value input by the ten key 1103 can be cleared by the clear key 1105.

  A reset key 1108 is a key for clearing the set contents and setting the initial state. A stop key 1107 is a key for interrupting a process being executed. The ID key 1104 is used when an ID number for authentication is input by the user.

  FIG. 4 is a diagram for explaining jam detection using the pre-registration conveyance sensor 160 and the paper conveyance sensor 171 in FIG.

  FIG. 4 shows a case where two jams, a stay jam and a delay jam, are detected. Further, both the pre-registration transport sensor 160 and the paper transport sensor 171 output “ON” when the paper is detected, and output “OFF” to the control unit 200 when the paper is not detected. .

  First, the retention jam will be described. The stay jam detection is started when the control unit 200 detects the passage of the trailing edge of the sheet by the pre-registration conveyance sensor 160 during the conveyance of the sheet. In the figure, it is the timing when the output of the pre-registration transport sensor 160 is turned from ON to OFF.

  The paper trailing edge passage time t1 at the paper conveyance sensor 171 can be calculated by dividing the distance L between the pre-registration conveyance sensor 160 and the paper conveyance sensor 171 by the paper conveyance speed V in this section.

  Note that the conveyance efficiency may be reduced depending on the durability of the conveyance roller and the configuration of the conveyance mechanism itself. Therefore, if the time taken into account is the conveyance margin m1, the sheet conveyance sensor 171 has a trailing edge of the sheet conveyance sensor 171. The time required to pass is within t1 + m1.

  Therefore, the control is performed when the paper conveyance sensor 171 cannot detect the passage of the trailing edge of the paper and the output of the paper conveyance sensor 171 remains ON as shown in the figure even though the time t1 + m1 has elapsed. The unit 200 determines that the jam is a retention jam.

  Next, delay jam will be described. Delay jam detection is started when the control unit 200 detects the passage of the leading edge of the sheet by the pre-registration conveyance sensor 160 during conveyance of the sheet. In the figure, it is the timing when the output of the pre-registration transport sensor 160 changes from OFF to ON.

  The time t2 when the leading edge of the paper reaches the paper transport sensor 171 can be calculated by dividing the distance L between the pre-registration transport sensor 160 and the paper transport sensor 171 by the paper transport speed V in this section. Note that t1 = t2 if the paper is transported at a constant speed between the pre-registration transport sensor 160 and the paper transport sensor 171.

  Note that the conveyance efficiency may decrease depending on the durability of the conveyance roller and the configuration of the conveyance mechanism itself. Therefore, if the time taken into consideration is the conveyance margin m2, the pre-registration conveyance sensor 160 to the sheet conveyance sensor 171 The time to reach is within t2 + m2 hours.

  Therefore, when the time t2 + m2 has elapsed, the paper transport sensor 171 cannot detect the leading edge of the paper and the output of the paper transport sensor 171 remains OFF as shown in the figure. Is identified as a delayed jam. As described above, the pre-registration conveyance sensor 160, the paper conveyance sensor 171, and the control unit 200 correspond to a jam detection unit that detects a jam in the conveyance path.

  The jam detection method described above is an example, and other methods may be used as long as the jam can be detected.

  FIG. 5 is a diagram for explaining the stay jam and the delay jam.

  FIG. 5 shows an example in which a stay jam and a delay jam occur in the vicinity of the fixing device 170.

  First, the stay jam will be described. As described above, the staying jam cannot be detected by the paper transport sensor 171 even though t1 + m1 has elapsed, and the output of the paper transport sensor 171 remains ON as shown in FIG. Is detected.

  As a cause of the stay jam, as shown in FIG. 5A, slip of the paper 401 at the fixing device 170 generated immediately after the leading edge of the paper 401 passes through the fixing device 170 and the paper transport sensor 171 can be cited. It is done.

  When the paper slips, the paper conveyance sensor 171 continues to detect the paper 401 because the trailing edge of the paper 401 does not pass through the paper conveyance sensor 171. At this time, as shown in FIG. 5A, since the leading edge of the paper 401 does not collide anywhere, the paper stops in a state where there is no buckling.

  Further, as another cause of the jamming, as shown in FIG. 5B, when the leading edge of the paper 402 passes through the fixing device 170 and the paper transport sensor 171 and passes in the vicinity of the transport flapper 172, the paper A failure of the transport flapper 172 that occurs so as to block the transport direction can be mentioned.

  When the paper transport direction is blocked due to a failure, the leading edge of the paper 402 collides with the transport flapper 172, and buckling starts at the leading edge of the paper 402. As a result, the sheet 402 is not further conveyed, and the rear end of the sheet 402 cannot pass through the sheet conveyance sensor 171, and the sheet conveyance sensor 171 continues to detect the sheet 402.

  At this time, as shown in FIG. 5B, the leading edge of the paper 402 collides with the transport flapper 172, and the paper 402 stops in a state where it is cramped.

  Regarding the stay jam that occurs due to the two factors described above, the control unit 200 cannot determine the presence or absence of buckling because the output of the paper transport sensor 171 remains ON in any case.

  Next, delay jam will be described. A delay jam occurs when the paper transport sensor 171 cannot detect the leading edge of the paper 403 and the output of the paper transport sensor 171 remains OFF as shown in FIG. Is detected.

  As a cause of the occurrence of the delay jam, as shown in FIG. 5C, the leading edge of the paper 403 passes through the fixing device 170 and is generated before the paper 403 reaches the paper transport sensor 171. Slip.

  At this time, as shown in FIG. 5C, the leading edge of the sheet 403 does not collide anywhere, and therefore the sheet 403 stops in a state where there is no buckling.

  Further, as another cause of the delay jam, as shown in FIG. 5D, after the leading end of the paper 404 passes through the fixing unit 170, the leading end of the paper 404 is curled upward and downstream of the fixing unit 170. The contact of the paper 404 with the side guide can be mentioned.

  The crooked paper 404 is not transported further downstream, and the leading end of the paper 404 cannot reach the paper transport sensor 171, so the output of the paper transport sensor 171 remains OFF.

  At this time, as shown in FIG. 5D, the leading end of the paper 404 comes into contact with the guide on the downstream side of the fixing device 170, and the use is stopped in a state where there is a buckling.

  Regarding the delay jam that occurs due to the two factors described above, the control unit 200 cannot determine the presence or absence of buckling because the output of the paper transport sensor 171 remains OFF in any case.

  In FIG. 5, it can be said that the sheets 401 and 403 that are not bent are less likely to be caught on the conveyance path, and thus can be automatically discharged.

  On the other hand, the crooked sheets 402 and 404 already collide with the conveyance flapper 172 and the guide on the downstream side of the fixing unit 170, and it can be said that automatic paper discharge is impossible.

  Further, not only in the case of buckling of the papers 402 and 404, but also in the case of other buckling, if automatic paper discharge is performed, further jamming will occur by contacting guides, flappers, branch points, etc. on the conveyance path. It may occur.

  Therefore, in order to automatically discharge paper, it is necessary to determine whether the paper is bent. For this determination, in this embodiment, the sound collecting device 310 is disposed in the vicinity of the paper transport sensor 171 and the acquired sound is analyzed to determine whether the paper is bent.

  FIG. 6 is a flowchart illustrating a procedure of print processing executed by the control unit 200 of FIG.

  The print processing in FIG. 6 will be described with reference to FIG. 7 showing an example of automatic paper discharge processing when a stay or delay jam occurs in the vicinity of the fixing device 170.

  In FIG. 6, when a print start is received from the input unit 205 (YES in step S500), the printing operation is started, and the control unit 200 starts recording the cover operation history using the above-described opening / closing sensor 320 (see FIG. 6). Step S501).

  Furthermore, the control unit 200 starts sampling the sound waveform data of the paper being conveyed using the sound collecting device 310 and stores the sampled data in the RAM 203 (step S502). That is, the RAM 203 corresponds to storage means for storing sound data (sound waveform data) indicating the sound collected by the sound collection device 310.

  In this embodiment, as an example, sampling is performed 512 times at a sampling period of 100 μ [sec] (sampling frequency is 10 k [Hz]), and the sampling is repeated until the job is completed. However, the present invention is not limited to this.

  Next, it is determined whether or not a stay or delay jam has occurred by the pre-registration conveyance sensor 160 and the paper conveyance sensor 171 (step S503).

  If it is determined in step S503 that no jam has occurred (NO in step S503), the process proceeds to step S513.

  On the other hand, if a jam occurs as a result of the determination in step S503 (YES in step S503), the jam is stopped (step S504). FIG. 7A shows an example of jam occurrence. In the jam stop, the downstream paper on the paper discharge side in the transport path from the transport roller 162 is continuously discharged as it is, and the upstream paper transport on the paper feed side in the transport path is stopped, and at the same time, the photosensitive drum 10 and the like. Also stop.

  Next, a cover operation history is acquired (step S505), and the sound waveform data sampled by the control unit 200 using the sound collector 310 is read from the RAM 203, and sound analysis is performed (step S506). Details of the sound analysis processing will be described later.

  Next, a transportability determination process is performed to determine whether the sheet can be transported using the result of the sound analysis process (step S507). The details of this transportability determination process will be described later.

  Next, it is determined from the conveyance determination process whether or not the sheet can be conveyed (step S508). If it is determined in step S508 that the sheet can be conveyed (NO in step S508), automatic paper discharge is executed (step S511). As described above, in this embodiment, when it is determined that the sheet is not in a cramped state, the sheet existing on the conveyance path is discharged.

  This will be described with reference to FIGS. 7B and 7C for explaining automatic paper discharge. First, as shown in FIG. 7B, the paper A, which is the jammed paper, is discharged to a discharge tray. Then, as shown in FIG. 7C, the remaining sheets B and C are discharged in the direction of the arrow in the figure.

  Note that the paper discharge destination at this time may be a preset tray for specifying residual paper discharge, or may be the closest paper discharge tray.

  After automatic paper discharge, jam recovery is started (step S512), and the process proceeds to step S513. The jam recovery here is to perform again the image forming operation that was scheduled to be performed on the paper A, paper B, and paper C remaining in the machine.

  On the other hand, if it is determined in step S508 that the sheet cannot be conveyed (YES in step S508), the display unit 206 displays that a jam has occurred (step S509).

  The contents displayed here are contents prompting the user to remove the upstream sheet on the sheet feeding side from the conveying roller 162 stopped by the control unit 200.

  When the jam processing by the user is completed (YES in step S510), jam recovery is started (step S512), and the process proceeds to step S513.

  Returning to the processing of step S503, if the result of determination in step S503 is that a jam has not occurred (NO in step S503), it is determined whether printing has ended (step S513).

  If the result of determination in step S513 is that printing has not ended (NO in step S513), the process returns to step S503.

  On the other hand, if the result of determination in step S513 is that printing has ended (YES in step S513), recording of the cover operation history is ended (step S514), sampling of the sound waveform data is ended (step S515), The process ends.

  In the jam stop (step S504) described above, the photosensitive drum 10 may be stopped, and the sound analysis process (step S506) and the transportability determination process (step S507) may be performed first. In this case, since it is possible to stop the sheet conveyance on the paper feeding side in the conveyance path after determining whether or not the sheet can be conveyed, the conveyance roller need not be stopped when the sheet conveyance is possible.

  The sound analysis process described above will be described. As described in step S <b> 501, the control unit 200 starts recording the cover operation history of the image forming apparatus 300 using the open / close sensor 320 when the printing operation is started.

  When the opening / closing operation is performed by the user, the control unit 200 detects it from the output of the opening / closing sensor 320. The detection result is recorded in the RAM 203.

  On the other hand, the ROM 202 stores the frequency at which the sound spectrum of the sound generated when the cover is opened and closed.

  FIG. 8A is a diagram showing an example of the frequency generated in the sound spectrum of the sound generated when the cover is opened and closed stored in the ROM 202 in FIG.

  As shown in FIG. 8 (A), it is known from the measurement results that a sound of 1500 to 2100 [Hz] is generated when the cover is opened and closed. Therefore, this frequency region is excluded so as not to be used for comparison with the paper state determination data.

  By doing in this way, when the cover opening / closing sound which overlaps the frequency range of the sound spectrum of the sound generated by buckling is generated, it is possible to prevent erroneous detection that the buckling has occurred.

  The frequency range that occurs when the cover is opened and closed and the accuracy of buckling detection are in a trade-off relationship, but the above range is a narrow range of 1500 to 2100 [Hz], and the user Operation and cramping rarely occur at the same time. Therefore, it is possible to achieve both the automatic paper discharge function and the prevention of erroneous detection.

  Next, determination of buckling will be described. First, frequency analysis is performed on the sound waveform data acquired by the sound collector 310 using Fast Fourier Transform (FFT). Then, the sound intensity for each frequency component is calculated for each frequency band. The result is set in the column of frequency component strength in the table.

  The fast Fourier transform is an example for performing frequency analysis, and is not limited to the frequency analysis method.

  FIG. 8B is a diagram showing a frequency spectrum (hereinafter referred to as “generated spectrum data”) obtained by converting sound waveform data into frequency domain data.

  As shown in FIG. 8B, in this embodiment, FFT processing is performed on a region of 100 to 5000 [Hz].

  FIG. 8C is a diagram showing the paper state determination data stored in the ROM 202 in FIG.

  The paper state determination data is data for determining whether or not the spectrum data is data including sound generated when the paper is bent.

  FIG. 8C shows the above-described lower limit value and upper limit value of the strength by assigning each frequency to A to J.

  A method for generating the paper state determination data will be described. The paper state determination data has an arbitrary number of frequencies in the frequency spectrum and the strength of frequency components corresponding to the frequency spectrum as a characteristic frequency spectrum when the paper is bent. In order to generate this characteristic frequency spectrum, attention is paid to the characteristics of the frequency and the strength of the frequency component.

  First, in order to extract the characteristics of the frequency, by colliding the paper with the conveyance flapper 172 during the paper conveyance, the sound waveform data when the paper is bent is obtained and the frequency analysis is performed. Since there are variations in the sound waveform data, sampling of the above sound waveform data is tried a plurality of times (for example, 30 times).

  Each of the 30 sound waveform data is subjected to frequency analysis, and the number of appearances of each frequency in the calculated frequency spectrum is extracted. Among them, a frequency that appears 20 times or more is regarded as a high frequency component, and this is a characteristic frequency.

  Next, in order to extract the characteristic of the strength of the frequency component, a histogram of the strength for each frequency of the frequency spectrum is generated in 30 samplings of the above sound waveform data.

  Among them, since the intensity of the frequency component at each frequency has the same variation as the frequency, an upper limit value and a lower limit value of the intensity of the frequency component are calculated, and this is a characteristic of the intensity of the frequency component.

  A combination of the frequency characteristics and the frequency component characteristics obtained in this way is used as paper state determination data. Other methods may be used as the method for generating the paper state determination data.

  The two data columns of the lower limit value and the upper limit value of the strength indicate the ranges that are determined to be suitable in the frequency band. That is, when the strength of the frequency component of the generated spectrum data is included in the range of the lower limit value and the upper limit value of the strength, it is determined that the frequency spectrum is suitable.

  FIG. 9 is a diagram illustrating an example of generated spectrum data, paper state determination data, and matching points.

  In FIG. 9, the upper limit value and the lower limit value of the paper state determination data are indicated by both ends of the arrow, and if the generated spectrum data is included in this range, it becomes a matching point. The spectrum region of the cover opening / closing sound is also shown, and it is determined whether or not it is a matching point in a region excluding this region.

  In this way, it is determined whether or not it is adapted at each frequency excluding the frequency at which the sound spectrum of the sound generated when the cover is opened and closed, and the number of adaptations is calculated by adding the number of adaptations.

  FIG. 8D shows a comparison result. The comparison result indicates the number of excluded points, the number of conforming points, and the conforming rate. In this embodiment, if the conforming rate is 70% or more, it is determined that the cramp is cramped. Use an appropriate value obtained by

  A flowchart of the sound analysis process described above will be described.

  FIG. 10 is a flowchart showing the procedure of the sound analysis process in step S506 in FIG.

  In FIG. 10, the sound waveform data acquired by the sound collector 310 is converted, and generated spectrum data obtained by the conversion is acquired (step S701). This step S701 corresponds to conversion means for converting the sound waveform data recorded in the RAM 203 into spectrum data indicating a frequency spectrum when a jam is detected.

  Next, a comparison process for comparing the paper state determination data read from the ROM 202 with the generated spectrum data is performed (step S702). Details of this comparison processing will be described later.

  Next, the number of matching points and the number of exclusion points obtained by the comparison process are acquired (step S704), the number of exclusion points is subtracted from the total number of data (step S704), the matching rate is calculated (step S705), and this process is terminated. To do. The method for calculating the total number of data and the precision will be described later.

  FIG. 11 is a flowchart showing the comparison processing procedure in step S702 of FIG.

  In FIG. 11, the number of excluded points is initialized to 0 (step S901), and the number of excluded data discrimination data i is initialized to 1 (step S902).

  Next, referring to the cover operation history, if there is a history that the cover has been opened and closed, the frequency generated by the sound spectrum of the sound generated when the cover is opened and closed shown in FIG. 8A is referred to. .

  Then, the processing using the array HERTZ [i] is performed, and this array is an array indicating the frequencies indicated in the paper state determination data in FIG. 8C. That is, HERTZ [1] = 400, HERTZ [2] = 1000, and so on.

  Next, it is determined whether or not the frequency indicated by the array HERTZ [i] is included in the frequency of the cover opening / closing sound (step S903). In the above-described example, since the frequency of the cover opening / closing sound is 1500 to 2100 [Hz], it is determined whether or not HERTZ [i] exists in this range.

  As a result of the determination in step S903, when the frequency indicated by the array HERTZ [i] is not included in the frequency of the cover opening / closing sound (NO in step S903), the process proceeds to step S905.

  On the other hand, as a result of the determination in step S903, when the frequency indicated by the array HERTZ [i] is included in the frequency of the cover opening / closing sound (YES in step S903), 1 is added to the exclusion score, and the exclusion determination information IGNORE [i] Is 1.

  This array IGNORE [i] is initialized in advance with 0, and is 0 when the frequency indicated by HERTZ [i] is not excluded, and 1 when excluded.

  Next, it is determined whether or not the number of excluded data determination data i has reached all the data N (step S905). As a result of the determination in step S905, when the number of excluded data determination data i has not reached all the data N (NO in step S905), 1 is added to the number of excluded data determination data i (step S906), and step S903. Return to.

  On the other hand, as a result of the determination in step S905, when the number of excluded data determination data i has reached all the data N (YES in step S905), the number of matching points is initialized to 0 (step S907), and the number of matching data determination data i is initialized to 1 (step S908).

  Next, it is determined whether IGNORE [i] is 0 (step S909). As a result of the determination in step S909, when IGNORE [i] is not 0 (NO in step S909), the process proceeds to step S912 because it is an exclusion target.

  On the other hand, as a result of the determination in step S909, if IGNORE [i] is 0 (YES in step S909), it is determined whether MIN [i] <FFT [HERTZ [i]] <MAX [i] (step S910). .

  Since FFT [HERTZ [i]] is the strength of the generated spectrum data at the frequency HERTZ [i], in step S910, the strength of the frequency component of the generated spectrum data is the lower limit value and the upper limit of the strength. It is determined whether or not it falls within the value range.

  If it is determined in step S909 that MIN [i] <FFT [HERTZ [i]] <MAX [i] is not satisfied (NO in step S910), the process proceeds to step S912.

  On the other hand, if MIN [i] <FFT [HERTZ [i]] <MAX [i] as a result of the determination in step S909 (YES in step S910), 1 is added to the number of matching points (step S911).

  Then, it is determined whether or not the number of matching data determination data i has reached all data N (step S912). As a result of determination in step S912, when the number of matching data determination data i has not reached all the data N (NO in step S912), 1 is added to the number of matching data determination data i (step S913), and step S909. Return to.

  On the other hand, as a result of the determination in step S912, when the number of matching data determination data i has reached the total number of data N (YES in step S912), this process ends.

  The control unit 200 that executes the sound analysis process including the comparison process, when the generation of the disturbance sound is detected after the paper is transported until the jam is detected, This corresponds to a discriminating means for discriminating the state of the paper from the spectrum data in the frequency domain excluding the frequency domain (C, D) where the disturbance sound exists from A to J). As a result, even when a disturbance noise is generated, since the determination is made by excluding them, the state of the recording medium in the conveyance path can be accurately determined.

  If the precision calculated in step S705 of the sound analysis process is large, there is a high possibility of being cramped, and if it is low, the possibility of being cramped is low. Will be determined.

  On the other hand, if no disturbance noise is detected after the paper is transported until a jam is detected (NO in step S903), the spectrum in a predetermined frequency region (A to J) is detected. The paper status is determined from the data.

  Next, the above-described FIG. 8 and the flowchart will be described in correspondence with each other.

  In the comparison process between the generated spectrum data and the paper state determination data shown in FIG. 8, first, the number of excluded points is calculated. The frequency band of the cover opening / closing sound is 1500 to 2100 [Hz].

  Accordingly, when sequentially comparing with the paper discrimination data, the frequencies C and D are excluded, and the exclusion score is 2.

  Next, the frequency of the generated spectrum data is within the range between the lower limit value (60 [Hz]) and the upper limit value (100 [Hz]) of the strength of the leading frequency (A: 400 [Hz]) of the paper state discrimination data. It is determined whether or not the frequency component strength (88 [Hz]) of (400 [Hz]) is included (step S910).

  In this case, since an affirmative determination is made (YES in step S910), 1 is added to the number of matching points, assuming that this frequency is matched (step S911).

  Thereafter, similarly, the process is repeated up to the total number N of paper state determination data (in this embodiment, N is 10 from A to J), that is, until the end of the paper state determination data.

  In the calculation of the relevance ratio, 8 obtained by subtracting the number of exclusion points 2 from the total number of data 10 is the denominator. If the number of matching points is 6, the matching rate is 75 [%].

  FIG. 12 is a flowchart showing a procedure of the conveyance feasibility determination process in step S507 in FIG.

  In FIG. 12, the matching rate is acquired (step S801), and it is determined whether the matching rate is 70% or more (step S802). As a result of the determination in step S802, if the relevance rate is not 70% or more (NO in step S802), there is no buckling, so that the conveyance is possible (step S804), and this process ends.

  On the other hand, as a result of the determination in step S802, if the matching rate is 70% or more (YES in step S802), there is a buckling, so that the conveyance is impossible (step S803), and this process is terminated.

  In the embodiment described above, the processing example for removing the cover opening / closing sound has been described. In the same manner, the key sound when the user inputs the operation unit is removed according to the key input history, or the sound that enters from the outside of the image forming apparatus at the place where the image forming apparatus is installed. Needless to say, it can be removed by using an external microphone.

(Other embodiments)
The present invention is also realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, etc.) of the system or apparatus reads the program code. It is a process to be executed. In this case, the program and the storage medium storing the program constitute the present invention.

119 Printer unit 170 Fixing unit 112 Double-sided conveyance path 122 Reverse conveyance path 200 Control unit 201 CPU
202 ROM
203 RAM
310 Sound Collector 320 Sensor

Claims (8)

An image forming apparatus having a conveyance path for conveying a recording medium,
Disturbance sound detection means for detecting the occurrence of a disturbance sound other than the sound generated by the recording medium when the recording medium is being transported through the transport path;
Jam detection means for detecting jams in the transport path;
Sound collecting means for collecting sound generated by the recording medium when the recording medium is conveyed along the conveyance path;
Storage means for storing sound data indicating the sound collected by the sound collection means;
A conversion unit that converts the sound data stored in the storage unit into spectrum data indicating a frequency spectrum when a jam is detected by the jam detection unit while the recording medium is being conveyed on the conveyance path. When,
When the generation of disturbance sound is detected by the disturbance detection means from when the recording medium is conveyed to when the jam detection means detects the jam, the disturbance noise is detected from a predetermined frequency range. An image forming apparatus comprising: a discriminating unit that discriminates a state of the recording medium from the spectrum data in a frequency domain excluding a frequency domain in which the recording medium exists.   The discriminating means is determined in advance if no disturbance sound is detected by the disturbance sound detecting means after the recording medium is conveyed and before the jam detecting means detects the jam. The image forming apparatus according to claim 1, wherein the state of the recording medium is determined from the spectrum data in a different frequency region.   The image forming apparatus according to claim 1, wherein the determination unit determines whether or not the recording medium is in a cramped state.   Whether the recording medium is in a state where the recording medium is crooked using the paper state discrimination data for determining whether the spectral data is data including sound generated when the recording medium is crooked. The image forming apparatus according to claim 3, wherein:   5. The recording medium according to claim 3, wherein when the determination unit determines that the recording medium is not in a cramped state, the recording medium existing in the conveyance path is discharged. Image forming apparatus.   The image forming apparatus according to claim 1, wherein the disturbance sound is a sound generated by a physical operation performed on the image forming apparatus. A transport path for transporting the recording medium, a disturbance sound detecting means for detecting the generation of a disturbance sound other than the sound generated by the recording medium when the recording medium is transported in the transport path, A control method for an image forming apparatus, comprising: jam detection means for detecting jamming; and sound collection means for collecting sound generated by the recording medium when the recording medium is being conveyed through the conveyance path,
A storage step of storing sound data indicating the sound collected by the sound collecting means;
A conversion step of converting the sound data stored in the storage unit into spectrum data indicating a frequency spectrum when a jam is detected by the jam detection unit while the recording medium is being conveyed on the conveyance path. When,
When the generation of disturbance sound is detected by the disturbance detection means from when the recording medium is conveyed to when the jam detection means detects the jam, the disturbance noise is detected from a predetermined frequency range. And a determination step of determining the state of the recording medium from the spectrum data in a frequency domain excluding the frequency domain in which there is. A transport path for transporting the recording medium, a disturbance sound detecting means for detecting the generation of a disturbance sound other than the sound generated by the recording medium when the recording medium is transported in the transport path, A computer executes a method for controlling an image forming apparatus, comprising jam detecting means for detecting a jam and sound collecting means for collecting sound generated by the recording medium when the recording medium is being conveyed through the conveying path. A program for
The control method is:
A storage step of storing sound data indicating the sound collected by the sound collecting means;
A conversion step of converting the sound data stored in the storage unit into spectrum data indicating a frequency spectrum when a jam is detected by the jam detection unit while the recording medium is being conveyed on the conveyance path. When,
When the generation of disturbance sound is detected by the disturbance detection means from when the recording medium is conveyed to when the jam detection means detects the jam, the disturbance noise is detected from a predetermined frequency range. And a determination step of determining a state of the recording medium from the spectrum data in a frequency domain excluding a frequency domain in which there is.

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