JP2020071442A - Image forming apparatus, conveyance number adjustment method, and computer program - Google Patents

Abstract

To reduce a burden on an operation to recover from paper jam compared with a prior art.SOLUTION: An image forming apparatus 1 having a pick-up roller 13B conveying a plurality of sheets one by one is provided with a determination unit 103 that determines the likelihood of the occurrence of paper jam in the image forming apparatus 1 based on information on a conveyance sheet that is at least one sheet of the plurality of sheets, and a paper feed control unit 102 that controls the pick-up roller 13B to reduce the number of the plurality of sheets to be conveyed at the same time as the likelihood of the occurrence of paper jam increases.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a technique for reducing a burden on a work for recovering from a paper jam in an image forming apparatus.

  Image forming apparatuses having various functions such as copying, scanning, faxing, and boxes have become popular. Such an image forming apparatus is sometimes called “MFP (Multi Function Peripherals)”.

  There are various types of paper used in the image forming apparatus. Recently, in terms of cost, thin paper, slippery paper, and backing paper that has been once printed and slightly rolled up may be used. When such paper is used, paper jam may easily occur in the image forming apparatus.

  If it is possible to determine whether a paper jam is likely to occur, that is, to predict that a paper jam will occur, a countermeasure can be taken before the paper jam occurs. The following patent documents disclose inventions that predict the occurrence of paper jams.

  The image forming apparatus described in Patent Document 1 uses an image carrier, an image forming unit that forms an image on the image carrier, and an image formed on the image carrier by the image forming unit as a recording material at a predetermined position. A transfer means for transferring, a paper feeding means for feeding the recording material toward the predetermined position after the image forming means starts forming an image on the image carrier, a paper feeding means and the predetermined position And a control means for controlling the conveyance of the recording material, and the CPU (control means) detects the detection result by the registration sensor (detection means). On the basis of the above, when image formation is continuously performed on a plurality of recording materials, the image forming interval Ti between the trailing edge of the image transferred to the preceding recording material and the leading edge of the image transferred to the subsequent recording material. Spread.

  In the image forming apparatus described in Patent Document 2, the fixing device is provided with a separation claw contact sensor that detects the contact of the recording paper P with the separation claw as a trajectory abnormality detection unit, and thus the recording after passing through the nip portion N is performed. By detecting a path abnormality in which the paper P draws a path different from the normal path, the occurrence of the separation abnormality in the separation unit α is detected. Then, by detecting the occurrence of the abnormal separation of the recording paper P in the separation section α, the occurrence of a jam is predicted, and the maintenance such as the parts replacement and the repair is performed in advance before the jam occurs, so that the user's time can be saved. The loss can be reduced.

  In the image forming apparatus described in Patent Document 3, a sheet detection sensor (A or the like) is arranged at a plurality of positions on a sheet conveyance path, and a jam occurrence detection unit detects a sheet depending on the sheet detection state of each sensor. The occurrence of a jam is detected for each occurrence location, the jam alarm counting unit at the corresponding location counts the jam occurrence information, and when the count value reaches the reference value, the jam alarm information is generated and the transmitting unit manages the jam alarm information. Send to. However, if the count value of the copy number counting unit reaches the paper jam standard value stored in the alarm level storage unit before the occurrence of the jam is detected, the count value of the jam occurrence information is reset.

JP, 2016-14831, A JP, 2006-11174, A JP-A-9-50156

Even if a paper jam is predicted and countermeasures are taken, the paper jam may occur due to insufficient countermeasures. When a paper jam occurs, it is necessary to perform recovery work, but this recovery work is a burden on the user. The invention described in the above-mentioned patent documents cannot reduce this burden.

In view of such problems, an object of the present invention is to reduce the burden on the work for recovering from a paper jam, as compared with the related art.

  An image forming apparatus according to an aspect of the present invention is an image forming apparatus having a conveying unit that conveys a plurality of sheets one by one, and information regarding a conveyed sheet that is at least one sheet of the plurality of sheets. A determination unit that determines the likelihood of occurrence of a paper jam in the image forming apparatus based on the above, and the greater the likelihood of occurrence of the paper jam, the more the number of the plurality of sheets to be conveyed at the same time is reduced. And control means for controlling the transport means.

  Or, it has an acquisition means for acquiring the paper passing time from when the conveyed paper starts to pass through a specific position to when it passes, and the discrimination means uses the acquired paper passing time as the information. Determine the likelihood of a jam.

  Alternatively, it has an acquisition unit that acquires a guide distance between the guide for guiding the plurality of sheets and the conveyance sheet, and the determination unit uses the acquired guide distance as the information and the paper jam. Determine the likelihood of occurrence of.

  Alternatively, it has an acquisition unit that acquires a transfer rate that indicates how close the density of the toner image transferred to the conveyance sheet is to the original density, and the determination unit uses the acquired transfer rate as the information. As a result, the likelihood of occurrence of the paper jam is determined.

  Alternatively, it has an acquisition unit that acquires the magnitude of the current that flows when the conveyed paper is neutralized, and the determination unit uses the acquired magnitude of the current as the information to determine whether the paper jam has occurred. Determine ease.

  Alternatively, a sheet passing time from when the conveying sheet starts to pass a specific position to when the conveying sheet finishes, a guide distance between a guide for guiding the plurality of sheets and the conveying sheet, and the sheet being transferred to the conveying sheet. At least two or more of the transfer rate indicating how close the density of the toner image is to the original density and the magnitude of the current flowing when the conveying paper is discharged are acquired as the information. And a determining unit, and the determining unit is configured to easily cause the paper jam based on at least two of the paper passing time, the guide distance, the transfer rate, and the magnitude of the current. To determine

  Or, it has a mitigating means for mitigating that the paper jam is likely to occur, and the discriminating means facilitates occurrence of the paper jam after mitigating that the paper jam is likely to occur by the mitigating means. Again, determine.

  According to the present invention, the burden on the work for recovering from a paper jam can be reduced more than ever before.

FIG. 3 is a diagram showing an example of an external appearance of an image forming apparatus. It is a figure which shows the example of the hardware constitutions of an image forming apparatus. It is a figure which shows the example of a structure of a print unit typically. It is a figure which shows typically the example of a structure of a conveyance guide unit. It is a figure showing an example of functional composition of an image forming device. It is a figure which shows the example of reference profile data. It is a figure which shows the example of a notification screen. 6 is a flowchart illustrating an example of the overall processing flow of the image forming apparatus. 6 is a flowchart illustrating an example of the overall processing flow of the image forming apparatus. It is a figure which shows the other example of reference profile data.

  FIG. 1 is a diagram showing an example of the external appearance of the image forming apparatus 1. FIG. 2 is a diagram showing an example of the hardware configuration of the image forming apparatus 1. FIG. 3 is a diagram schematically showing an example of the configuration of the print unit 10m. FIG. 4 is a diagram schematically showing an example of the configuration of the transport guide unit 18. FIG. 5 is a diagram showing an example of the functional configuration of the image forming apparatus 1.

  The image forming apparatus 1 shown in FIG. 1 is an apparatus in which functions such as copying, PC printing, cloud printing, fax, scanner, and box are integrated. Generally, it may be called a “multifunction peripheral” or “MFP (Multi Function Peripherals)”.

  The PC print function is a function of printing an image on paper based on image data received from a terminal device within the same LAN (Local Area Network) as the image forming apparatus 1. It is also called “network printing” or “network print”.

  The cloud print function is a function of receiving image data from an external terminal device via a server on the Internet and printing an image on paper.

  The box function is a function in which a storage area called a “box” or a “personal box” is given to each user, and each user stores and manages image data and the like in his or her own storage area. It is also possible to provide a box for each group and share it with the members of the group. The box corresponds to a “folder” or a “directory” in a personal computer.

  As shown in FIG. 1 or 2, the image forming apparatus 1 includes a CPU (Central Processing Unit) 10a, a RAM (Random Access Memory) 10b, a ROM (Read Only Memory) 10c, an auxiliary storage device 10d, a touch panel display 10e, and an operation. The key panel 10f, the NIC (Network Interface Card) 10g, the wireless LAN communication unit 10h, the modem 10i, the temperature / humidity sensor 10j, the scan unit 10k, the print unit 10m, and the like.

  The CPU 10a is a main CPU of the image forming apparatus 1. The RAM 10b is a main memory of the image forming apparatus 1.

  The touch panel display 10e displays a screen showing a message to the user, a screen for the user to input a command or information, a screen showing the result of the processing executed by the CPU 10a, and the like. Further, it sends a signal indicating the touched position to the CPU 10a.

  The operation key panel 10f is a so-called hardware keyboard, and includes a numeric keypad, a start key, a stop key, a function key, and the like.

  The NIC 10g communicates with other devices using a protocol such as TCP / IP (Transmission Control Protocol / Internet Protocol).

  The wireless LAN communication unit 10h communicates with other devices based on a wireless LAN standard, that is, IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard.

  The modem 10i exchanges document data with a fax terminal using a protocol such as G3.

  The temperature / humidity sensor 10j measures the temperature t and the humidity h of the place where the image forming apparatus 1 is installed at predetermined time intervals (for example, every one minute). Hereinafter, the measured temperature t will be referred to as “measured temperature t1”, and the measured humidity h will be referred to as “measured humidity h1”.

  The scan unit 10k reads an image written on a document (sheet) set on an ADF (Auto Document Feeder) or platen glass to generate image data.

  The print unit 10m prints the image read by the scan unit 10k, the image shown in the image data received from the terminal device or the like by the NIC 10g, the wireless LAN communication unit 10h, or the modem 10i on paper.

  The print unit 10m is a tandem type or electrophotographic type color print engine. As shown in FIG. 3, the toner bottle 11, the image forming unit 12, the paper feeding unit 13, the intermediate transfer belt 14, the secondary transfer unit 15, the paper passing sensor 16, the transfer belt cleaning blade 17, the conveyance guide unit 18, and the fixing. It is composed of the unit 19 and the like.

  One toner bottle 11 and one image forming unit 12 are provided for each of cyan, magenta, yellow, and black. Hereinafter, the cyan toner bottle 11 and the image forming unit 12 will be described as an example.

  The toner bottle 11 stores replenishing cyan toner. The image forming unit 12 includes a photoconductor drum 12A, a charging unit 12B, an exposure unit 12C, a developing roller 12D, a photoconductor cleaning blade 12E, and the like.

  The photoconductor drum 12A is a photoconductor drum for cyan. The charging unit 12B uniformly charges the surface of the photoconductor drum 12A in a negative polarity.

  The exposure unit 12C forms an electrostatic latent image on the photosensitive drum 12A by performing exposure according to the image of the image data based on the signal from the CPU 10a. The exposure unit 12C is composed of, for example, a semiconductor laser.

  The developing roller 12D forms the toner image on the photosensitive drum 12A by supplying the cyan toner of the toner bottle 11 to the electrostatic latent image.

  The photoconductor cleaning blade 12E removes the toner remaining on the surface of the photoconductor drum 12A.

  The magenta, yellow, and black toner bottles 11 and the image forming unit 12 also have the same roles as the cyan toner bottle 11 and the image forming unit 12, respectively, and form magenta, yellow, and black toner images on the photosensitive drums. 12A.

  The paper feeding unit 13 includes one or more paper feeding cassettes 13A and one or more pickup rollers 13B. The paper stored in the paper feed cassette 13A is taken out from the paper feed cassette 13A by the pickup roller 13B and is transported via the transport path indicated by the chain double-dashed line in FIG.

  When printing an image on a plurality of sheets, the plurality of sheets, for example, a maximum of seven sheets are conveyed in the image forming apparatus 1 immediately before the certain sheet is taken out from the paper feed cassette 13A. Hereinafter, the sheet being conveyed in the image forming apparatus 1 will be referred to as “conveying sheet”.

  The intermediate transfer belt 14 is endless (that is, annular) and rotates at a constant speed. Toner images of the respective colors formed on the photosensitive drums 12A of cyan, magenta, yellow, and black are primarily transferred onto the intermediate transfer belt 14.

  The secondary transfer unit 15 is composed of a secondary transfer roller 15A, a backup roller 15B, a pressure adjusting unit 15C and the like.

  The secondary transfer roller 15A and the backup roller 15B sandwich the sheet conveyed from the sheet feeding unit 13 and the intermediate transfer belt 14 to secondarily transfer the toner image on the intermediate transfer belt 14 onto the sheet. Further, the secondary transfer roller 15A applies a voltage to the paper when the secondary transfer is performed. That is, it is applied to the paper.

  The pressure adjusting unit 15C adjusts the pressure at which the secondary transfer roller 15A and the backup roller 15B nip the paper or the like (hereinafter, referred to as “nip pressure p”). Hereinafter, the default clamping force p will be referred to as “clamping force p0”.

  The paper passing sensor 16 is arranged in the vicinity of the secondary transfer unit 15, and each time the paper passes in front of the paper passing sensor 16, it takes time for the paper to pass through the paper passing sensor 16 (hereinafter, referred to as “passage”). Paper time pt "). Hereinafter, the measured paper passing time pt will be referred to as “measured paper passing time pt1”. The sheet passing time pt becomes longer as the sheet becomes harder to pass the secondary transfer unit 15.

  The transfer belt cleaning blade 17 removes the toner remaining on the intermediate transfer belt 14 after the secondary transfer.

  As shown in FIG. 4, the transport guide unit 18 includes a charge removing member 18A, an application unit 18B, a current sensor 18C, a transfer density reading sensor 18D, a transport guide 18E, a transport guide 18F, and a guide sensor 18G.

  The charge removing member 18A is a saw-tooth-shaped or brush-shaped metal member, and removes charges accumulated on the paper by the secondary transfer. That is, the paper is discharged.

  A voltage having a polarity opposite to that of the charge of the paper is applied to the charge removing member 18A by the applying unit 18B. When the paper with the accumulated charges approaches the charge removing member 18A, discharge is generated, and the paper is discharged.

  The current sensor 18C measures the magnitude of a current (hereinafter, referred to as “separation current i”) that flows due to discharge that occurs when the sheet is neutralized by the static elimination member 18A. Hereinafter, the measured separation current i will be referred to as “measurement separation current i1”.

  As the voltage applied to the charge removing member 18A increases, the discharge and separation current i also increases, and the amount of charge removed from the paper increases. A voltage having a constant magnitude (hereinafter, referred to as “voltage v”) is applied to the static elimination member 18A. Hereinafter, the default voltage will be referred to as “voltage v0”.

  The transfer density reading sensor 18D measures how close the density of the toner image is secondarily transferred to the intended original density (that is, how accurate the density of the toner image is secondarily transferred). Specifically, the ratio of the density c1 of the toner image secondarily transferred to the sheet to the original density c0 of the entire sheet is measured. Hereinafter, this ratio is referred to as "transfer rate r". That is, r = (c1 / c0) × 100 [%]. Further, the measured transfer rate r will be referred to as “measured transfer rate r1”.

  The transfer density reading sensor 18D measures the transfer rate r every time the sheet passes in front of the transfer density reading sensor 18D.

  The transport guides 18E and 18F guide the paper along the transport path. The transport guide 18E is disposed outside the bent portion of the transport path, and the transport guide 18F is disposed so as to face the transport guide 18E.

  The guide sensor 18G is arranged in the vicinity of the conveyance guide 18E, and the distance between the conveyance guide 18E and the sheet (hereinafter, referred to as “guide distance d”) each time the sheet passes in front of the guide sensor 18G. To measure. Hereinafter, the measured guide distance is referred to as “measurement guide distance d1”. The guide distance d becomes longer as the sheet and the transport guide 18F are closer to each other.

  The fixing unit 19 (see FIG. 3) includes a heating roller 19A and a pressure roller 19B. The heating roller 19A and the pressure roller 19B fix the toner image on the paper by heating and sandwiching the paper that has been secondarily transferred.

  The ROM 10c or the auxiliary storage device 10d stores an application for realizing the above-described functions such as copying. Further, a paper jam handling program 10P (see FIG. 5) is stored as one of the programs related to printing.

  The paper jam handling program 10P is a program that mainly reduces the number of sheets of paper retained in the image forming apparatus 1 when the paper jam is likely to occur in the image forming apparatus 1 as compared with the normal case. According to the paper jam handling program 10P, the profile storage unit 101 to the alleviation unit 105 of FIG. 5 are realized in the image forming apparatus 1. The details of this program will be described later.

  FIG. 6 is a diagram showing an example of the reference profile data 6A. FIG. 7 is a diagram showing an example of the notification screen 5A.

  Hereinafter, the operation of the profile storage unit 101 to the relaxation unit 105 of FIG. 5 will be described with reference to FIGS. 6 and 7 by taking the case where the image forming apparatus 1 copies a plurality of originals as an example.

  The profile storage unit 101 of the image forming apparatus 1 stores reference profile data 6A as shown in FIG.

  In the reference profile data 6A, each sensor (that is, each of the paper passing sensor 16, the current sensor 18C, the transfer density reading sensor 18D, and the guide sensor 18G) measures whether or not a paper jam is likely to occur in the image forming apparatus 1. A range or a value serving as a criterion for making a determination based on the result is shown.

  The reference profile data 6A is stored for each object measured by each sensor (that is, for each sheet passing time pt, separation current i, transfer rate r, and guide distance d).

  The user sets a plurality of originals on the scan unit 10k. The conditions for executing printing are set in the image forming apparatus 1, and the execution of printing is instructed. Then, the following processing is performed.

  The paper feed control unit 102 (see FIG. 5) determines the time interval (hereinafter, referred to as “conveyance interval ti”) during which the pickup roller 13B conveys the paper, based on the condition for performing printing. The pickup roller 13B is controlled so that the sheet is conveyed according to the determined conveyance interval ti. Hereinafter, the transport interval ti (that is, the default transport interval ti) determined on the basis of the condition for performing printing is referred to as “transport interval ti0”.

  The temperature / humidity sensor 10j measures the temperature t and the humidity h at predetermined time intervals. The temperature / humidity data 6B indicating the measured temperature t1 and the measured humidity h1 is sent to the CPU 10a.

  The paper passing sensor 16 measures the paper passing time pt of the paper every time the paper passes the paper passing sensor 16. Time data 6C indicating the measurement paper passing time pt1 is sent to the CPU 10a.

  The current sensor 18C measures the separation current i each time a discharge occurs. The current data 6D indicating the measurement separation current i1 is sent to the CPU 10a.

  The transfer density reading sensor 18D measures the transfer rate r of the paper every time the paper passes the transfer density reading sensor 18D. Transfer rate data 6E indicating the measured transfer rate r1 is sent to the CPU 10a.

  The guide sensor 18G measures the guide distance d of the sheet each time the sheet passes the guide sensor 18G. Distance data 6F indicating the measurement guide distance d1 is sent to the CPU 10a.

  The determination unit 103 determines whether or not a paper jam is likely to occur in the image forming apparatus 1 based on the data received from each sensor and the reference profile data 6A (hereinafter referred to as “occurrence determination processing”). .) As follows.

  The determination unit 103 determines which range or value of the “normal” and “warning” of the reference profile data 6A the value indicated by each received data falls within. If at least one of the received data falls within the "warning" range a predetermined number of times (for example, 5 times), it is determined that a paper jam is likely to occur. Hereinafter, the predetermined number of times may be referred to as a “threshold number”.

  When one or more of the received data is larger than the “normal” range or value of the reference profile data 6A and exceeds the “warning” range, or smaller than the “normal” range or value. If it is less than the “warning” range, the determination unit 103 may determine that a paper jam has occurred in the image forming apparatus 1. Then, the image forming unit 12 and the like may be controlled so that the printing is interrupted.

  Before performing the generation determination process for the measured separation current i1, the determination unit 103 determines whether the reference profile data 6A (that is, the reference profile data 6A2) of the separation current i is “normal” or “warning”, respectively, as necessary. Is corrected based on the measured temperature t1 and the measured humidity h1 shown in the temperature / humidity data 6B.

  For example, when the measured temperature t1 is 25 ° C. or higher and the measured humidity h1 is 80% or higher, the determination unit 103 multiplies the ranges or values of “normal” and “warning” of the reference profile data 6A2 by 1.5. .. That is, “normal” “5 μA or more” is corrected to “7.5 μA or more”, and “abnormal” “2 μA to less than 5 μA” is corrected to “3 μA or more and less than 7.5 μA”.

  Hereinafter, information for correcting the reference profile data 6A, such as the measured temperature t1 and the measured humidity h1, will be referred to as “correction information”.

  When the reference profile data 6A2 is corrected, the determination unit 103 performs the generation determination process using the corrected range or value.

  When the determination unit 103 determines that a paper jam is likely to occur, the paper feed control unit 102 reduces the maximum number of sheets to be conveyed from the current number (for example, by about 20%). Redetermine the transport interval ti. That is, the transport interval ti is redetermined as the transport interval ti1 which is longer than the transport interval ti0. The pickup roller 13B is controlled so that the sheet is transported according to the transport interval ti1 that has been determined again.

  For example, if the current maximum number of sheets to be conveyed is seven, the paper feed control unit 102 redetermines the conveyance interval ti to a conveyance interval ti1 such that the maximum number of sheets becomes five, and the conveyance interval ti is determined. The pickup roller 13B is controlled based on ti1.

  The distance between the trailing portion of the previously transported sheet and the leading portion of the later transported sheet is longer at the transport interval ti1 than at the transport interval ti0.

  Hereinafter, the process of reducing the maximum number of conveyed sheets from the current number will be referred to as “number limit process”.

  When the paper feed control unit 102 performs the number limit processing, the screen output unit 104 displays the notification screen 5A that notifies that the maximum number of conveyed sheets has decreased, as shown in FIG. 7, on the touch panel display 10e. Output to.

  When the determination unit 103 determines that the paper jam is likely to occur, the mitigation unit 105 performs the following process (hereinafter, referred to as “mitigation process”) for mitigating that the paper jam is likely to occur. To do so.

  When the measured paper passing time pt1 is within the range of “warning”, the easing unit 105 controls the pressure adjusting unit 15C so that the clamping pressure p becomes smaller than the current one.

  The sheet becomes harder to pass through the secondary transfer unit 15 as the pinching pressure p increases. Then, the trailing portion of the previously conveyed sheet may collide with the leading portion of the later conveyed sheet. As a result, a paper jam may occur in the secondary transfer unit 15.

  Therefore, the clamping pressure p is made smaller than the current one. As a result, it becomes easier for the paper to pass through the secondary transfer unit 15 than at the present time, and it is possible to prevent the previously conveyed paper and the later conveyed paper from colliding with each other.

  The mitigation unit 105 also controls the application unit 18B so that the voltage v becomes larger than the current one when the measurement separation current i1 or the measurement guide distance d1 is within the “warning” range.

  When the secondary transfer roller 15A is applied to the paper, electric charges are accumulated on the paper. As the amount of accumulated charge increases, the sheet is more likely to be bent toward the secondary transfer roller 15A.

  When the sheet is easily bent to the side of the secondary transfer roller 15A, the sheet may come into contact with, for example, the conveyance guide 18F or the inner wall of the bent portion of the conveyance path during the conveyance. As a result, a paper jam may occur in the transport guide unit 18 or the like.

  Therefore, the voltage v is made higher than the current one. As a result, the amount of electric charge removed from the paper becomes larger than that of the current one, and the paper can be returned from the easily bent state to the original state or a state close to the original state.

  The easing unit 105 also controls the application unit 18B in the same manner as described above even when the measured transfer rate r1 is within the “warning” range.

  A sheet in which the density of the secondary-transferred toner becomes lower than the originally intended density is generally high in resistance and difficult to eliminate the charge. Therefore, the voltage v is made higher than the current one so that the paper can be sufficiently discharged.

  The mitigation unit 105 may also control the image forming unit 12 and the like so that the margin portion of the paper becomes smaller than the current one when performing the mitigation process.

  As the margin portion of the sheet becomes larger, the number of portions where the intermediate transfer belt 14 and the sheet directly contact each other (that is, portions where the intermediate transfer belt 14 does not contact the toner image). If this portion increases, the paper may be difficult to separate from the intermediate transfer belt 14. As a result, paper jam may occur in the secondary transfer unit 15.

  Therefore, the margin of the paper is made smaller than the current one. As a result, the number of portions where the intermediate transfer belt 14 and the paper sheet are directly in contact with each other is smaller than that of the present one, and the paper sheet is more easily separated from the present one.

  In order to reduce the margin of the paper, for example, the size of the image printed on the paper may be increased by several% from the current size.

  The easing unit 105 may also control the fixing unit 19 so that the temperature of the heating roller 19A becomes lower than the current one when performing the easing process.

  As the temperature of the heating roller 19A rises, the sandwiched paper becomes easier to bend. A sheet that is easily bent may curl around the discharge port after being discharged from the image forming apparatus 1 and block the discharge port. As a result, a paper jam may occur near the discharge port.

  Therefore, the temperature of the heating roller 19A is made lower than the current one. As a result, it is possible to prevent the sandwiched paper from easily refracting as compared with the present.

  The easing unit 105 also makes the speed at which the paper is conveyed and the speed at which printing is performed (hereinafter, referred to as “process speed”) slower than the current speed when performing the easing process. The pickup roller 13B or the like may be controlled. Note that the range or value of the reference profile data 6A of the sheet passing time pt is corrected to be larger than the current one according to the extent to which the speed at which the sheet is conveyed becomes slower.

  The screen output unit 104 may include a notification indicating which of the above-described relaxation processes is being performed in the notification screen 5A.

  Even after the number-of-sheets limitation process and the relaxation process are started, each sensor sends data indicating the measurement result to the CPU 10a.

  When a predetermined number (for example, 10) of images have been printed on the paper after the number-of-sheets limitation process and the relaxation process are started, the determination unit 103 performs the generation determination process again in the same manner as described above.

  Note that the determination unit 103 uses the data received from each sensor when a predetermined number of images are printed on the sheet when the occurrence determination process is performed again.

  When the determination unit 103 determines that the paper jam is not likely to occur, the paper feed control unit 102 suspends the number-of-sheets limiting process. That is, the transportation interval ti is returned to the default (that is, the transportation interval ti0), and the pickup roller 13B is controlled based on the transportation interval ti0.

  On the other hand, when the determination unit 103 determines that a paper jam is likely to occur, the paper feed control unit 102 repeats the above-described sheet number limiting process.

  For example, if the paper feed controller 102 is currently controlling the pickup roller 13B based on the transport interval ti1, the transport interval ti is set to four sheets, which is 20% less than the current maximum number of transport sheets, which is five. The transport interval ti2 is set so that The pickup roller 13B is controlled based on the conveyance interval ti2.

  If the current conveyance interval ti is such that the maximum number of conveyed sheets is the minimum number (for example, two sheets), the sheet feeding control unit 102 does not repeat the number limitation process. In this case, the current transport interval ti is maintained.

  When the determination unit 103 determines that the paper jam is not likely to occur, the relaxation unit 105 suspends the relaxation process. That is, the pressure adjusting unit 15C is controlled so that the current clamping pressure p returns to the default (that is, clamping pressure p0), and the application unit 18B is controlled so that the current voltage v returns to the default (that is, voltage v0). In addition, the size of the margin, the temperature of the heating roller 19A, and the process speed are restored.

  On the other hand, when the determination unit 103 determines that the paper jam is likely to occur, the alleviation unit 105 repeats the above alleviation process.

  For example, the relaxation unit 105 controls the pressure adjusting unit 15C so that the clamping pressure p becomes smaller than the current one when the measured paper passing time pt1 is within the range of “warning”. When the measurement separation current i1, the measurement guide distance d1, or the measurement transfer rate r1 is within the “warning” range, the application unit 18B is controlled so that the voltage v becomes larger than the current one. Further, the size of the margin portion may be smaller than the current one, the temperature of the heating roller 19A may be lower than the current one, and the process speed may be slower than the current one.

  If the current clamping pressure p is the minimum, the relaxation unit 105 does not repeat the relaxation process of the pressure adjustment unit 15C. In this case, the current clamping pressure p is maintained. If the current voltage v is the maximum, the relaxation process of the application unit 18B is not repeated. In this case, the current magnitude of the voltage v is maintained. Further, if the current size of the blank space is the maximum, the relaxation process for the blank space is not repeated, and if the current temperature of the heating roller 19A is the minimum, the relaxation process for the temperature of the heating roller 19A is not repeated. If the process speed is slowest, the relaxation process for the process speed is not repeated.

  8 and 9 are flowcharts showing an example of the overall processing flow of the image forming apparatus 1.

  Next, the overall flow of processing in the image forming apparatus 1 will be described with reference to the flowcharts of FIGS. 8 and 9.

  The image forming apparatus 1 executes the process in the procedure shown in FIGS. 8 and 9 based on the paper jam handling program 10P.

  When the execution of printing is instructed by the user after the condition for executing printing is input (Yes in # 601 of FIG. 8), the image forming apparatus 1 determines the carrying interval ti (# 602), and the carrying interval ti0. Then, the sheet is started to be conveyed and the temperature t, the humidity h, etc. are started to be measured (# 603).

  The image forming apparatus 1 performs an occurrence determination process based on the data received from each sensor and the reference profile data 6A (# 604). At this time, if the measured temperature t1 and the measured humidity h1 are predetermined values, the reference profile data 6A2 is corrected.

  When the image forming apparatus 1 determines that a paper jam is likely to occur (Yes in # 605), the number of sheets limitation process is performed (# 606), the relaxation process is performed (# 607), and the re-determined conveyance interval ti is used. The paper is conveyed (# 608).

  When the image forming apparatus 1 prints an image on a predetermined number of sheets before the printing is completed after the number of sheets limiting process and the relaxing process are performed (No in # 609, Yes in # 610), the occurrence determination is performed. The process is performed again (# 604). When it is determined that the paper jam is likely to occur (Yes in # 605), the number of sheets limiting process and the relaxing process are repeated (# 606 to # 610).

  When the image forming apparatus 1 determines that the paper jam is not likely to occur (No in # 605), if the sheet number limiting process and the mitigation process are performed (Yes in # 611 of FIG. 9), the conveyance interval ti and the like are set. Return to default (# 612). Until printing is completed (No in # 613), the processes of steps # 603 to # 613 are repeated.

  The image forming apparatus 1 performs the processes of steps # 601 to # 614 until the service ends (Yes in # 614).

  According to the present embodiment, it is possible to reduce the burden on the work for recovering from a paper jam as compared with the related art.

[Modification]
FIG. 10 is a diagram showing another example of the reference profile data 6A. In the above-described embodiment, a plurality of stages are set in the range of "warning" of the reference profile data 6A, and which of the plurality of stages of "warning" the data received from the sensor enters the threshold number of times. According to the above, the likelihood of occurrence of paper jam may be determined.

  For example, it is assumed that reference profile data 6A as shown in FIG. 10 is stored in the profile storage unit 101. Further, it is assumed that the current transport interval ti and the clamping pressure p are each default.

  When the measured sheet passing time pt1 falls within the range of “warning (low)” for the threshold number of times, the determination unit 103 determines the likelihood of paper jam in the image forming apparatus 1 as “low”. On the other hand, when the measured paper passing time pt1 is within the range of "warning (high)" for the threshold number of times, the likelihood of occurrence of paper jam in the image forming apparatus 1 is determined to be "high".

  If the susceptibility to paper jam is “low”, the paper feed control unit 102 performs the sheet number limiting process so that the maximum number of conveyed sheets is slightly smaller (for example, about 20%) than the present number. I do. On the other hand, if the susceptibility to paper jam is “high”, the number limitation process is performed so that the maximum number of conveyed sheets is considerably smaller (for example, about 50%) than the present number.

  In other words, the paper feed control unit 102 sets the maximum number of sheets of conveyed paper to be smaller than the current one as the paper jam is more likely to occur (that is, the maximum number of conveyed sheets of paper is smaller than the present one). So as to reduce) as well.

  If the easiness of paper jam occurrence is “low”, the easing unit 105 performs the easing process so that the clamping pressure p becomes slightly smaller (for example, about 20%) than the current one. On the other hand, if the easiness of paper jam occurrence is “high”, the relaxation process is performed so that the clamping pressure p becomes considerably smaller (for example, about 50%) than the current one.

  Further, the measurement separation current i1, the measurement guide distance d1, and the measurement transfer rate r1 may be the same as the measurement sheet passing time pt1.

  For example, assume that the current transport interval ti and the voltage v are each default. When the measurement separation current i1 falls within the range of “warning (low)” for the threshold number of times, the determination unit 103 determines that the likelihood of paper jam in the image forming apparatus 1 is “low”.

  If the likelihood of occurrence of a paper jam is “low”, the paper feed control unit 102 performs the number limiting process so that the maximum number of conveyed sheets is slightly smaller than the current number, and the alleviating unit 105. Performs a relaxation process so that the clamping pressure p becomes slightly smaller than the current one.

  On the other hand, when the measured separation current i1 is within the range of "warning (high)" for the threshold number of times, the determination unit 103 determines that the likelihood of paper jam in the image forming apparatus 1 is "high".

  If the likelihood of a paper jam occurring is “high”, the paper feed control unit 102 performs the number limiting process so that the maximum number of conveyed sheets is considerably smaller than the present number. The relaxation unit 105 also performs the relaxation process so that the voltage v becomes considerably higher than the current one.

  Regarding the size of the margin portion, the temperature of the heating roller 19A, and the process speed, the degree to which the mitigation process is performed changes depending on whether the data enters "warning (low)" or "warning (high)". It should be done.

  In the above-described embodiment, the sheet passing sensor 16 measures the time taken for the sheet to pass through the sheet passing sensor 16, but after the sheet conveyed first passes through the sheet passing sensor 16, the sheet is conveyed later. It may be possible to measure the time taken for the formed sheet to start passing through the sheet passing sensor 16.

  In the above-described embodiment, the image forming apparatus 1 is provided with a sensor that detects the type of paper (hereinafter, referred to as “paper type”), and the paper type of the conveyance paper detected by the sensor and the image forming apparatus 1 are provided. If the stored paper type of the paper stored in the paper feed cassette 13A does not match a predetermined number of times, the determination unit 103 may determine that a paper jam is likely to occur.

  In the above-described embodiment, when the conveyed paper is a paper such as a thin paper and a backing paper in which a paper jam is likely to occur, when the sensor that detects the paper type detects the paper a predetermined number of times, the determination unit 103 causes the paper jam. You may decide that it is easy to do. Further, the notification screen 5A may include a notification that the paper type should be changed.

  In the above-described embodiment, the reference profile data 6A stored in the profile storage unit 101 may be updated (determined) by machine learning.

  For example, the value of each sensor when a paper jam occurs is collected as learning data. Using these learning data, the conditions for occurrence of a paper jam with a certain probability or more are obtained by machine learning. The reference profile data 6A is updated (determined) so that the obtained conditions are reflected.

  When the image forming apparatus 1 is shipped from the factory, nothing is stored in the profile storage unit 101, and when the reference profile data 6A is generated (determined) by machine learning as described above, the reference profile data 6A may be stored in the profile storage unit 101.

  Note that the updated (determined) reference profile data 6A may be shared with another image forming apparatus 1 via, for example, a communication line.

  In the above embodiment, the measurement temperature t1 and the measurement humidity h1 are used as the correction information. However, other than the temperature t and the humidity h, the environmental information (for example, atmospheric pressure) indicating the environment of the place where the image forming apparatus 1 is installed, the states of the members of the image forming apparatus 1 such as the rotation speed of the photosensitive drum 12A, etc. The member information, the cumulative number of printed sheets, history information indicating a history of the type of printing (for example, color printing) executed by the image forming apparatus 1, or information of a paper type may be used as the correction information. Further, the correction profile may be used to correct the reference profile data 6A other than the reference profile data 6A of the separation current i.

  In the above-described embodiment, when the determination unit 103 determines that the paper jam is likely to occur, the fact may be notified to the manufacturer of the image forming apparatus 1 through a communication line or the like.

  In the above-described embodiment, the determination unit 103 performs the occurrence determination process again when a predetermined number of images are printed on the paper after the number of sheets limiting process and the relaxing process are started.

  However, the determination unit 103 may perform the occurrence determination process again when a predetermined time (for example, 1 minute) has elapsed after the number-of-sheets limitation process and the relaxation process were started. At this time, the occurrence determination process is performed using the data received from each sensor when a predetermined time has elapsed.

  In the above-described embodiment, the static elimination member 18A is applied, but the static elimination member 18A may be grounded after the position of the static elimination member 18A can be changed. The alleviation unit 105 changes the position of the charge removing member 18A so that the distance between the paper and the charge removing member 18A is shorter than that of the current one, so that the amount of electric charge removed from the paper is smaller than that of the current one. Do more.

  In the above-described embodiment, if the data received from the sensor enters the “normal” range one or more times before the data enters the “warning” range for the threshold number of times, the data You may reset the number of times of entering into the range of "warning".

  In the above embodiment, the threshold number of times may be changed according to the type of the received data. In particular, the threshold number of times of the transfer rate r is preferably set to be larger than that of the others.

  Determining whether or not a paper jam is likely to occur based on the transfer rate r tends to have more errors than determining based on other data such as the separation current i. Therefore, the threshold number of times of the transfer rate r is set to be larger than that of others in order to be able to discriminate carefully.

  In the above-described embodiment, when the determination unit 103 determines that the paper jam is not likely to occur when the number-of-sheets limiting process is repeatedly performed, the paper feed control unit 102 returns the transport interval ti in stages. May be.

  For example, assume that the transport interval ti is changed to the transport interval ti0, the transport interval ti1, and the transport interval ti2, and the sheet is currently transported at the transport interval ti2. At this time, when it is determined that the paper jam is not likely to occur, the paper feed control unit 102 returns the current transportation interval ti to the transportation interval ti1.

  Similarly, if the relaxation unit 105 determines that paper jam is not likely to occur when the relaxation process is repeatedly performed, the clamping pressure p, the voltage v, and the like may be gradually returned.

  In the above-described embodiment, when the measured transfer rate r1 is within the range of "warning" for the threshold number of times, the voltage applied to the paper by the secondary transfer roller 15A (hereinafter, referred to as "transfer voltage") is higher than the normal voltage. May also be increased. Further, at this time, the relaxation unit 105 applies a voltage v, which is larger than the voltage v applied to the static elimination member 18A, to the static elimination member 18A in the relaxation process.

  In the above-described embodiment, the range from the side in contact with the “warning” range of the upper limit side or the lower limit side of the “normal” range of the reference profile data 6A to the predetermined range is the “normal” range, and the remaining range is It may be a range of "second warning". Then, if the value shown in the received data falls within the range of the “second warning” for the threshold number of times, the determination unit 103 determines that the image forming apparatus 1 is not in a normal operating state, and therefore the image forming apparatus 1 has a paper jam. May be determined to occur easily.

  For example, the “normal” range of the reference profile data 6A1 is limited to “1 second or more and less than 1.75 seconds”, and the “second alert” range is “less than 1 second”. When the measured sheet passing time pt1 is less than 1 second a predetermined number of times, the determining unit 103 determines that the image forming apparatus 1 is likely to cause a paper jam.

  The reference profile data 6A2 and the reference profile data 6A4 may be limited similarly to the case of the reference profile data 6A1. That is, for the reference profile data 6A2, for example, the range of “normal” is limited to “5 μA or more and less than 7 μA” and the range of “second warning” is “7 μA or more”. Regarding the reference profile data 6A4, for example, the range of “normal” is limited to “2 mm or more and less than 3 mm” and the range of “second warning” is set to “less than 2 mm”.

  Regarding the reference profile data 6A3, if the measured transfer rate r1 exceeds the value of “normal” a predetermined number of times, the determining unit 103 may determine that the image forming apparatus 1 is likely to cause a paper jam.

  As for the range of the "second warning", a plurality of stages may be set similarly to the range of the "warning".

  Alternatively, instead of defining the ranges of “normal”, “warning”, and “second warning” in the reference profile data 6A, ideal values in normal time and an allowable range of deviation may be defined. Then, the determination unit 103 may determine that a paper jam is likely to occur if the deviation between the value of the received data and the ideal value in the normal state does not fall within the threshold number of times or the allowable range.

  For example, in the sheet passing time pt, an ideal value in a normal state is defined as 1.75 seconds, and a deviation allowable range is defined as between 1.5 seconds and less than 2 seconds. If the measured paper passing time pt1 is less than the predetermined number of times of 1.5 seconds, it is determined that the paper jam easily occurs.

  Alternatively, the value of the received data is monitored and recorded. Then, the determination unit 103 determines that a paper jam is likely to occur if the difference between the maximum value of the received data values and the minimum value of the received data values exceeds a predetermined value. May be. That is, it may be determined that the paper jam is likely to occur based on the change in the value of the received data.

  The above-described embodiments and modifications may be combined as needed. The conditions necessary for realizing the combined contents may be experimentally obtained in advance.

  In addition, the configuration of the entire image forming apparatus 1 or each part such as the conveyance guide unit 18, the content and order of each process such as the occurrence determination process, the number-of-sheets limiting process and the mitigation process, the configuration of data such as the reference profile data 6A, and the like are as follows. It can be appropriately changed in accordance with the gist of the present invention.

1 Image forming apparatus 6A Reference profile data (reference)
13B Pickup roller (conveying means)
15 Secondary transfer unit (transfer means)
16 Paper passing sensor (acquisition means, specific position)
18A static elimination member (applying means)
18C current sensor (acquisition means)
18D transfer density reading sensor (acquisition means)
18E, 18F Transport guide (guide)
18G guide sensor (acquisition means)
19 Fixing unit (fixing means)
101 profile storage unit (storage means)
102 paper feed control unit (control means)
103 discrimination unit (discrimination means)
105 Relaxation unit (relaxation means)
d1 measurement guide distance (information, guide distance)
h1 Measured humidity (environmental information)
i1 Measurement separation current (information, magnitude of current)
p Clamping force (force)
pt1 measurement paper passing time (information, paper passing time)
r1 transfer rate (information, transfer rate)
t1 Measured temperature (environmental information)
ti Transport interval (interval)
v voltage

Claims (14)

An image forming apparatus having a conveying unit that conveys a plurality of sheets one by one,
Determination means for determining the likelihood of occurrence of a paper jam in the image forming apparatus based on information about the conveyed paper, which is at least one of the plurality of papers,
A control unit that controls the conveying unit so as to reduce the number of the plurality of sheets that are conveyed at the same time as the paper jam is more likely to occur.
An image forming apparatus comprising: The transport sheet has an acquisition unit that acquires a sheet passage time from when the sheet starts to pass a specific position to when the sheet passes.
The determining unit determines the easiness of occurrence of the paper jam by using the acquired paper passing time as the information.
The image forming apparatus according to claim 1. A guide for guiding the plurality of sheets and an acquisition unit for acquiring a guide distance between the conveyance sheets,
The determination unit determines the likelihood of occurrence of the paper jam, using the acquired guide distance as the information.
The image forming apparatus according to claim 1. And a transfer unit that acquires a transfer rate indicating how close the density of the toner image transferred to the conveyance paper is to the original density.
The determining means determines the likelihood of occurrence of the paper jam, using the acquired transfer rate as the information.
The image forming apparatus according to claim 1. An acquisition unit that acquires the magnitude of the electric current that flows when the transport paper is neutralized,
The determination unit determines the likelihood of occurrence of the paper jam, using the magnitude of the acquired current as the information.
The image forming apparatus according to claim 1. Paper passing time from when the conveying paper starts to pass a specific position to when the conveying paper finishes passing, a guide distance between a guide for guiding the plurality of sheets and the conveying paper, toner transferred to the conveying paper At least two or more of the transfer rate indicating how close the image density is to the original density and the magnitude of the current flowing when the transport paper is discharged are acquired as the information. Have means,
The determining unit determines the likelihood of occurrence of the paper jam based on at least two of the paper passing time, the guide distance, the transfer rate, and the magnitude of the current,
The image forming apparatus according to claim 1. Having a mitigating means for mitigating that the paper jam easily occurs,
The determination means determines again the easiness of occurrence of the paper jam after the ease of occurrence of the paper jam is mitigated by the mitigation means.
The image forming apparatus according to claim 1. Transfer means for transferring the toner image onto the conveying paper,
An applying unit that applies a voltage to the conveyance sheet in order to neutralize the conveyance sheet;
A fixing unit configured to fix the toner image on the conveyance sheet,
The easing unit reduces the force with which the transfer unit sandwiches the conveyed sheet to be smaller than the present force, and the magnitude of the voltage applied by the applying unit to the conveyed sheet is smaller than the present voltage. , The margin portion of the conveyance sheet is made smaller than the present margin portion, and the fixing unit heats the conveyance sheet at a temperature lower than the present temperature, or the conveyance sheet is conveyed. By slowing the speed lower than the current speed, the paper jam is less likely to occur,
The image forming apparatus according to claim 7. A storage unit that stores a reference for determining the likelihood of occurrence of the paper jam,
The determination means determines the likelihood of occurrence of the paper jam using the reference,
The image forming apparatus according to claim 1. The reference is environmental information indicating the environment of the place where the image forming apparatus is installed, member information indicating the state of the members of the image forming apparatus, or history information indicating the printing history of the image forming apparatus. Will be corrected based on
The image forming apparatus according to claim 9. The reference is determined based on the information when the paper jam occurs in the image forming apparatus in the past,
The image forming apparatus according to claim 9. The control means controls the carrying means so as to reduce the number of the plurality of papers carried at the same time by increasing the interval when the carrying means carries the plurality of papers one by one.
The image forming apparatus according to claim 1. Transport multiple sheets of paper one by one into the image forming device,
The easiness of occurrence of a paper jam in the image forming apparatus is determined based on information about the transport paper, which is at least one of the plurality of papers,
As the paper jam is more likely to occur, the number of the plurality of sheets conveyed at the same time is reduced,
A method for adjusting the number of conveyed sheets, which is characterized in that A computer program for controlling an image forming apparatus having a conveying unit that conveys a plurality of sheets one by one,
In the image forming apparatus,
A process of determining the likelihood of a paper jam in the image forming apparatus is executed based on information about a transport sheet that is at least one sheet of the plurality of sheets,
As the paper jam is more likely to occur, a process of controlling the carrying unit is executed so as to reduce the number of the plurality of sheets to be carried at the same time.
A computer program characterized by the above.

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