JP5882250B2 - Image forming apparatus and paper feed roller wear detection method - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus and a paper feed roller wear detection device, and more specifically, image formation capable of accurately detecting wear of the paper feed roller by accurately grasping the form of wear of the paper feed roller. The present invention relates to an apparatus and a feed roller wear detection method.

  Conventionally, when a paper feed roller that transports paper from a paper feed cassette to an image forming unit is worn, the transport capability of the paper feed roller is reduced, or a paper jam (JAM) occurs in the paper transport path. In order to prevent these inconveniences, the image forming apparatus performs a detection process for detecting the wear of the paper feed roller.

  As the detection processing, for example, by measuring the transport time from the start of paper feeding by the paper feed roller to the time of paper detection by a sensor provided in advance in the paper transport path, Wear is detected. Specifically, a reference transport time as a reference is calculated in advance by calculation or actual measurement, and the actual transport time of the paper is actually measured for each paper transport, and the reference transport time and the actual transport time are compared. Thus, the wear of the paper feed roller is detected.

  For example, Japanese Patent Laid-Open No. 5-58482 (Patent Document 1) discloses a nudger roller that is pressed with a certain pressure on the upper part of a sheet accommodated in a sheet accommodating device, and feeds the sheet from the sheet accommodating device, and a downstream portion of the nudger roller. And a paper sensor disposed at a downstream portion of the paper separation mechanism so that the paper fed from the paper storage device is nipped by the paper separation mechanism and then the pressure applied by the nudger roller is released. A sheet feeding device of an image forming apparatus configured as described above is disclosed. In the paper feeding device, a paper sensor is arranged in the downstream portion of the paper separating mechanism, and a means for measuring the time when the paper sent from the paper feeding device is detected by the sensor by the paper sensor is provided in the control device. The time for sending out the paper by pressing the nudger roller against the paper is set using the data on the time for sending out the paper. As a result, even if the feeding performance of the paper separation mechanism by the paper feed roller or nudger roller is reduced, the time of feeding by the nudger roller can be automatically extended using the time data when the paper is detected by the paper sensor. In this case, the feeding operation from the paper storage device can be surely performed.

  Japanese Patent Laid-Open No. 6-80277 (Patent Document 2) discloses that a paper feed roller that feeds paper from a paper storage unit, a paper feed sensor provided on a paper transport path, and the paper feed roller are turned on. Subsequently, there is disclosed a paper feeding abnormality warning device for a copying machine provided with means for bringing down the device as a paper feeding failure when the time until the paper feeding sensor is turned on exceeds a certain time. In the paper feed abnormality warning device, the time measuring means for measuring a specific time shorter than the predetermined time, and the time until the paper feed sensor is turned on after the paper feed roller is turned on is equal to or longer than the specific time. And a warning means for issuing a warning for prompting replacement of the paper feed roller. As a result, it is possible to notify that the paper feed roller should be replaced before the copying operation becomes impossible, so that substantial down can be eliminated and the reliability of the apparatus can be improved. .

  Japanese Patent Application Laid-Open No. 2003-95460 (Patent Document 3) detects the presence or absence of a sheet in a sheet conveyance path and a registration roller for feeding out the sheet in time with an image formed on an image carrier. And measuring the time from the paper feed start signal at the time of paper feeding until the paper sensor detects the leading edge of the paper, and based on the measured time, the number of rotations of the motor related to paper conveyance is determined. An image forming apparatus capable of correction is disclosed. The image forming apparatus includes a first motor related to paper conveyance upstream of the registration rollers, and a second motor related to paper conveyance after the registration rollers. The first motor is the second motor. The number of rotations can be controlled independently, and n is an integer equal to or greater than 1, and the number of rotations of the first motor at the time of transporting the nth sheet is R (n), and at the time of transporting the nth sheet of paper When the time from the paper feed start signal until the paper sensor detects the leading edge of the paper is T (n) and the predetermined value set in advance is T0, the rotational speed R of the first motor that transports the (n + 1) th paper. Control is performed so that (n + 1) becomes R (n + 1) = R (n) × T (n) ÷ T0. This prevents an increase in roller slip when the load is large, an increase in slip due to a decrease in the μ of the roller over time, a decrease in the linear speed of the paper due to wear of the roller, and a decrease in productivity due to the paper conveyance load. it can. Further, since the delay of the sheet linear velocity can be corrected, it is possible to extend the component life of the sheet conveying unit, and to realize cost reduction and environmental impact reduction.

JP-A-5-58482 Japanese Patent Laid-Open No. 6-80277 JP 2003-95460 A

  However, when paper is fed, there is a case where the conveyance of the paper is delayed in a single shot due to the gloss of the paper, dust, or the initial slip of the paper feed roller. Also, there is a possibility that even a delay in transporting a sheet may be detected as wear of the paper feed roller, and there is still a problem that the wear of the paper feed roller cannot be detected with high accuracy.

  Further, the wear of the paper feed roller progresses as the paper is transported, the outer diameter of the paper feed roller gradually decreases, and the paper transport capability gradually decreases accordingly. Therefore, if the characteristics of the wear of the paper feed roller are accurately grasped, there is a possibility that the wear of the paper feed roller can be detected with high accuracy.

  Accordingly, the present invention has been made to solve the above-described problem, and an image capable of accurately detecting the wear of the paper feed roller by accurately grasping the form of wear of the paper feed roller. It is an object of the present invention to provide a forming apparatus and a feed roller wear detection method.

  In order to solve the above-described problems and achieve the object, the image forming apparatus according to the present invention measures an actual conveyance time required for conveyance of the paper in a predetermined section when the paper is conveyed by a paper feed roller. Accordingly, the following configuration is adopted on the premise of an image forming apparatus that detects wear of the paper feed roller.

  That is, the image forming apparatus includes: a first determination unit that determines whether or not the actually measured conveyance time exceeds a reference conveyance time calculated using an unworn paper feed roller; When the measured transport time exceeds the reference transport time, the rank of the actually measured transport time calculated for each sheet transport using the rank table that ranks the length of the measured transport time step by step. Counting means for counting the number of sheets, second determination means for determining whether or not the length of the actually measured transport time for each transport of each sheet is continuously increased based on the result of the number of ranks, As a result of the determination, when it is determined that the number of ranks has increased continuously, the image forming apparatus includes a detecting unit that detects that the paper feed roller is worn.

  In addition, when the measured transport time exceeds the reference transport time, the creating unit for creating the rank table, and the rank table when it is determined that the number of ranks does not continuously increase And erasing means for erasing.

  Further, the first determination means subtracts the reference transport time from the measured transport time, calculates the subtracted value as a paper transport time difference, and whether the paper transport time difference exceeds a preset threshold value. By determining whether or not, it is determined whether or not the actually measured transport time exceeds the reference transport time.

  In addition, the ranking table is a ranking table in which a difference range in which the threshold value is increased step by step and a rank indicating the size of the difference range are associated with each other.

  The second determination means determines whether the number of ranks A ranked in the smallest difference range among the ranks in the ranking table does not exceed a predetermined number of times. It is determined whether or not the length of the actually measured transport time for each transport is continuously increased.

  According to the present invention, when the paper is transported by the paper feed roller, the paper feed roller wear detection detects the wear of the paper feed roller by measuring an actual transport time required for transporting the paper in a predetermined section. Can be provided as a method.

  That is, the paper feed roller wear detection method includes a first determination step for determining whether or not the actually measured transport time exceeds a reference transport time calculated using an unworn paper feed roller; As a result, when the actual transport time exceeds the reference transport time, the actual transport calculated for each paper transport using the rank table that ranks the length of the actual transport time stepwise. A counting step for counting the number of ranks of time, and a second determination for determining whether or not the length of the actually measured conveyance time for each conveyance of each sheet is continuously increased based on the result of the number of ranks And a detection step of detecting that the paper feed roller is worn when it is determined that the number of ranks has continuously increased as a result of the determination.

Further, the present invention can be provided as a program for causing a computer to circulate individually via a telecommunication line or the like. In this case, the central processing unit (CPU) implements the control operation in cooperation with each circuit other than the CPU according to the program of the present invention. Each means realized by using the program and the CPU can also be configured by using dedicated hardware. Further, the program may also be circulating in a state of being recorded on a computer-readable remembers medium such as a CD-ROM.

  According to the image forming apparatus and the feed roller wear detection method of the present invention, it is possible to accurately detect the wear of the feed roller by accurately grasping the form of wear of the feed roller.

1 is a conceptual diagram illustrating an overall configuration inside a multifunction peripheral according to the present invention. It is a conceptual diagram which shows the whole structure of the operation part which concerns on this invention. It is a figure which shows the structure of the control system hardware of the multifunctional device which concerns on this invention. FIG. 2 is a functional block diagram of a multifunction machine according to an embodiment of the present invention. It is a flowchart for showing the execution procedure of the embodiment of the present invention. FIG. 6 is a diagram (FIG. 6A) showing an example of a ranking table according to the embodiment of the present invention, and a diagram (FIG. 6B) showing an example of a single paper conveyance delay. FIG. 7A is a diagram illustrating an example of a ranking table corresponding to a single paper transport delay (FIG. 7A), and FIG. 7B is a diagram illustrating an example of a continuous paper transport delay (FIG. 7B). . FIG. 8A shows an example of a ranking table corresponding to continuous paper conveyance delays (FIG. 8A), and FIG. 8 shows an example of an exchange screen displayed on the touch panel according to the embodiment of the present invention. (B)).

  Hereinafter, an embodiment of an image forming apparatus according to the present invention will be described with reference to the accompanying drawings for understanding of the present invention. In addition, the following embodiment is an example which actualized this invention, Comprising: The thing of the character which limits the technical scope of this invention is not. Moreover, the alphabet S added before the number in a flowchart means a step.

<Image forming apparatus>
Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described. FIG. 1 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention. However, details of each part not directly related to the present invention are omitted.

  Note that the image forming apparatus according to the present invention corresponds to, for example, a printer or a multifunction machine including a printer, a copy, a scanner, a fax, and the like, and includes an image having a copy function, a scanner function, a facsimile function, a printer function, and the like. Functions as a forming device.

  The operation of the MFP 100 (MFP: Multi Function Peripheral) when using the copy function will be briefly described below.

  First, when the user uses the multifunction machine 100, the document is placed on the document table 101 provided on the upper surface of the casing. Subsequently, the user uses the operation unit 102 (operation panel) provided in the vicinity of the document table 101 to input setting conditions related to image formation from the operation screen of the operation unit 102. When the user presses a start key provided on the operation unit 102, the multifunction peripheral 100 starts image formation (print processing).

  Next, in the image reading unit 103, the light emitted from the light source 104 is reflected by the document placed on the document table 101. The reflected light is guided to the image sensor 108 by the mirrors 105, 106, and 107. The guided light is photoelectrically converted by the image sensor 108, and image data corresponding to the original is generated.

  An image forming unit 109 forms a toner image based on the image data. The image forming unit 109 is provided with a photosensitive drum 110. The photosensitive drum 110 rotates in a predetermined direction at a constant speed, and around the charger drum 111, the exposure unit 112, the developing unit 113, the transfer unit 114, the cleaning unit 115, and the like in that order from the upstream side in the rotation direction. Is arranged.

  The charger 111 uniformly charges the surface of the photosensitive drum 110. The exposure unit 112 irradiates the charged surface of the photosensitive drum 110 with a laser based on the image data to form an electrostatic latent image. The developer 114 forms a toner image by attaching toner to the formed electrostatic latent image. The formed toner image is transferred to a recording medium (for example, paper, sheet) by the transfer device 114. The cleaning unit 115 removes excess toner left on the surface of the photosensitive drum 110. A series of these processes is executed by rotating the photosensitive drum 110.

  The paper is transported from a plurality of paper feed cassettes 116 provided in the multifunction peripheral 100. When transported, the paper is pulled out from any one of the paper feed cassettes 116 to a transport path by a paper feed roller (pickup roller) 117. Each paper feed cassette 116 accommodates different types of paper, and paper is fed (conveyed) based on setting conditions relating to image formation.

  The sheet pulled out to the conveyance path is sent between the photosensitive drum 110 and the transfer device 114 by the conveyance roller 118 and the registration roller 119. When the paper is fed, the toner image is transferred to the paper by the transfer device 114 and conveyed to the fixing device 120.

  When the paper on which the toner image has been transferred passes between a heating roller and a pressure roller provided in the fixing device 120, heat and pressure are applied to the toner image, and the visible image is fixed on the paper. The The amount of heat of the heating roller is optimally set according to the paper type, and the fixing is performed appropriately. The visible image is fixed on the paper and the image formation is completed, and the paper is guided to the path switching unit 121 by the transport roller 118.

  In the path switching unit 121, the sheet is guided to a sheet discharge tray 122 provided on a side surface of the casing unit or the casing through the sheet discharge port 123 according to a switching instruction from the multifunction peripheral 100. To the in-body tray 124 provided in the body cylinder. The sheets are stacked and stored on the paper discharge tray 122 or the in-body tray 124. By the above procedure, the casing unit 125 of the multifunction peripheral 100 provides an image forming function to the user.

  Here, a sheet detection sensor 126 that detects the conveyance (passage) of the sheet is previously provided in the vicinity of the conveyance roller 118 through which the sheet conveyed from each sheet cassette 116 via the sheet supply roller 117 passes in common. The multifunction peripheral 100 is configured to be able to measure the time from the time when each paper feed roller 117 starts rotating until the time when the paper detection sensor 126 detects the paper.

  FIG. 2 is a conceptual diagram showing the overall configuration of the operation unit according to the embodiment of the present invention. The user uses the operation unit 102 to input setting conditions for image formation as described above, and to confirm the input setting conditions. When the setting conditions are input, a touch panel 201 (operation panel), a touch pen 202, and operation keys 203 provided in the operation unit 102 are used.

  The touch panel 201 has both a function for inputting setting conditions and a function for displaying the setting conditions. That is, by pressing a key in the screen displayed on the touch panel 201, a setting condition corresponding to the pressed key is input.

  A display unit (not shown) such as an LCD (Liquid Crystal Display) is provided on the back surface of the touch panel 201, and the display unit displays an operation screen such as the initial screen, for example. A touch pen 202 is provided in the vicinity of the touch panel 201. When the user brings the tip of the touch pen 202 into contact with the touch panel 201, a sensor provided under the touch panel 201 detects the touch destination.

  Further, a predetermined number of operation keys 203 are provided in the vicinity of the touch panel 201, and for example, a ten key 204, a start key 205, a clear key 206, a stop key 207, a reset key 208, and a power key 209 are provided.

  Next, the configuration of the control system hardware of the multifunction peripheral 100 will be described with reference to FIG. FIG. 3 is a diagram showing the configuration of the control system hardware of the multifunction peripheral 100 according to the present invention. However, details of each part not directly related to the present invention are omitted.

  The control circuit of the MFP 100 includes a CPU (Central Processing Unit) 301, a ROM (Read Only Memory) 302, a RAM (Random Access Memory) 303, a HDD (Hard Disk Drive) 304, a driver 305 corresponding to each driving unit, and an operation. The unit 306 (102), the paper feed roller 307 (117), and the paper detection sensor 308 (126) are connected by an internal bus 309.

  The CPU 301 uses, for example, the RAM 303 as a work area, executes a program stored in the ROM 302, the HDD 304, and the like, and based on the execution result, data and instructions from the driver 305 and the operation unit 306, key 1 is transmitted and received, and the operation of each drive unit shown in FIG. 1 is controlled.

  Further, the CPU 301 obtains the start time of rotation of the paper feed roller 307 and the detection time point of the paper by the paper detection sensor 308, and measures the actually measured transport time required for transporting the paper in a predetermined section. Further, with respect to each means (shown in FIG. 4) to be described later other than the driving unit, the CPU 301 implements each means by executing a program. The ROM 302, the HDD 304, and the like store programs and data for realizing each means described below.

<Embodiment of the present invention>
Next, the configuration and execution procedure according to the embodiment of the present invention will be described with reference to FIGS. 4 and 5. FIG. 4 is a functional block diagram of the multifunction machine of the present invention. FIG. 5 is a flowchart for illustrating the execution procedure of the present invention.

  First, when a user places a predetermined document on the document table 101 and turns on the power of the multifunction device 100, the display reception unit 401 of the operation unit 102 of the multifunction device 100 displays a predetermined operation screen (initial screen). Display on the touch panel 201.

  When the user inputs desired setting conditions (for example, the paper size “A4”, the number of copies of 100 sheets, etc.) while viewing the operation screen and presses the start key 205, the display receiving unit 401 performs the setting. The condition and the pressing of the start key 205 are accepted, and that is notified to the image forming unit 402. Upon receiving the notification, the image forming unit 402 starts execution of image formation based on the setting condition and the original (FIG. 5: S101).

  Here, when the image forming unit 402 starts execution of image formation, the measurement unit 403 is notified to that effect. Upon receiving the notification, the measuring unit 403 measures the actually measured transport time Tr (sec) required for transporting the paper in a predetermined section when the paper for execution of image formation is transported by the paper feed roller 117. (FIG. 5: S102).

  Any method may be used for the measurement unit 403 to measure the actually measured transport time Tr. For example, first, the measurement unit 403 passes in common regardless of the paper size. Monitoring of the sheet detection sensor 126 provided in advance at the location is started. Next, when the image forming unit 402 starts to rotate the paper feed roller 117 corresponding to the size “A4” of the image formation target paper, the measuring unit 403 detects the start of rotation of the paper feed roller 117. Then, the elapsed time from the rotation start time of the paper feed roller 117 is measured using a predetermined timer. On the other hand, when the paper transported (feeded) by the rotation of the paper feed roller 117 is detected by the paper detection sensor 126, the measurement unit 403 detects the passage of the paper via the paper detection sensor 126. The timer is stopped and the elapsed time is acquired. As a result, the elapsed time from the rotation start time of the paper feed roller 117 to the paper detection time of the paper detection sensor 126 can be measured as the actually measured transport time Tr required for paper transport in a predetermined section.

  When the measurement unit 403 completes the measurement of one actually measured transport time Tr, the measurement unit 403 notifies the first determination unit 404 to that effect. Then, it is determined whether or not the reference transport time Ts (sec) calculated using the unworn paper feed roller 117 is exceeded.

  Here, the reference transport time Ts is the sheet of the sheet detection sensor 126 from the start of rotation of the sheet feed roller 117 when the sheet is transported using the unworn (new) sheet feed roller 117. It means the time measured or theoretically calculated for the elapsed time until the detection time. Therefore, if the measured transport time Tr exceeds (long) the reference transport time Ts, it means that there is a high possibility that the paper feed roller 117 is worn.

  Since the reference transport time Ts is provided for each paper feed roller 117 corresponding to the paper size, the first determination unit 404 uses the predetermined paper feed roller 117 used for transporting the paper. The above-described determination is performed based on the actually measured transport time Tr and the reference transport time Ts corresponding to the paper feed roller 117.

  Any method may be used for the first determination unit 404 to determine whether or not the actually measured transport time Tr exceeds the reference transport time Ts. For example, the first determination First, the means 404 subtracts the reference transport time Ts corresponding to the paper feed roller 117 at the measured transport time Tr from the measured transport time Tr, and calculates the subtraction value Te (sec) as the sheet transport time difference ( FIG. 5: S103).

  Here, the reason for calculating the paper transport time difference Te is that since the time required for transporting the paper has a small fluctuation amount, the measured transport time Tr is shorter than the reference transport time Ts by determining the difference. This is because it can be accurately determined whether or not the length has been increased.

  Next, the first determination unit 404 determines whether or not a rank table to be described later exists (FIG. 5: S104).

  Here, since the ranking table does not yet exist, the first determination unit 404 determines that the ranking table does not exist (FIG. 5: S104 NO), and the first determination unit 404 determines that the sheet It is determined whether or not the transport time difference Te exceeds a preset threshold Ta (sec) (FIG. 5: S105). In addition, when the said ranking table exists (FIG. 5: S104NO), it mentions later.

  Here, the threshold value Ta is a setting value set by a user such as an administrator. For example, the threshold value Ta is based on an actually measured transport time Tr at which wear of the paper feed roller 117 starts and a corresponding reference transport time Ts. The calculated value is preferable because the wear of the paper feed roller 117 can be detected efficiently.

  As a result of the determination, when the paper transport time difference Te does not exceed the threshold Ta (FIG. 5: S105 NO), the first determination unit 404 determines that the actual transport time Tr exceeds the reference transport time Ts. It determines with not having carried out, and complete | finishes a process. In this case, since the paper feed roller 117 is not worn at all (similar to a new one), it is not necessary to detect the wear of the paper feed roller 117 itself.

  On the other hand, if the paper transport time difference Te exceeds the threshold Ta as a result of the determination (FIG. 5: S105 YES), the first determination unit 404 determines that the measured transport time Tr exceeds the reference transport time Ts. The creation unit 405 is notified of that. Receiving the notification, the creating unit 405 creates a ranking table in which the length of the actually measured transport time Tr is ranked in stages (FIG. 5: S106).

  Here, the creation unit 405 may create any method for creating the ranking table. For example, the creation unit 405 uses the threshold value Ta as shown in FIG. In this way, the ranking table 600 is created in which the difference range 601 in which the threshold value Ta is increased step by step and the rank 602 indicating the size of the difference range 601 are associated with each other. Specifically, the creating means 405 creates thresholds Tb and Tc that are stepwise larger than the threshold Ta, and the first difference range where Te is a range equal to or smaller than Ta and Te exceeds Ta, And a second difference range that is a range that is equal to or less than Tb, a third difference range that is a range where Te exceeds Tb and is equal to or less than Tc, and a fourth difference that is a range where Te exceeds Tc. A range is created as a difference range 601. Here, for example, Tb is set as 2 * Ta and Tc is set as 3 * Ta. Next, the creating means 405 associates rank A with the smallest first difference range in the created difference range 601, associates rank B with the second smallest difference range, and ranks the third smallest difference range 601. Rank C is associated with the third difference range, and rank D is associated with the largest fourth difference range. Thereby, the ranking table 600 is completed. The number of the difference ranges 601 and the rank 602 symbols may be set arbitrarily. Further, when the ranking table 600 is created, it is stored in a predetermined memory.

  When the creation unit 405 completes the creation of the ranking table 600, it notifies the counting unit 406 to that effect, and the counting unit 406 that has received the notification uses the ranking table 600 for each conveyance of each sheet. The number of ranks of the actually measured transport time Tr calculated in (1) is counted (FIG. 5: S107).

  Specifically, the counting means 406 first associates the paper transport time difference Te calculated previously with one of the difference ranges 601 of the ranking table 600 and associates it with the associated difference range 601. 1 is added to the number of ranks 602 and counted.

  For example, as shown in FIG. 6B, for example, the paper feed by the paper feed roller 117 is delayed by a single delay due to the gloss of the paper, dust or the initial slip of the paper feed roller 117, and When the paper transport time difference Te corresponding to the paper feeding becomes significantly large, the counting means 406 ranks the paper transport time difference Te based on the ranking table 600 as shown in FIG. Rank D, add 1 to the number of rank D, and count. The counted number of ranks is associated with the ranking table 600. This makes it easy to grasp the condition of the paper feed roller 117 from the number and frequency of occurrence for each rank.

  When the counting means 406 completes the counting, it is determined whether or not the counted number of ranks has exceeded a first predetermined number of times (for example, 5 times) (FIG. 5: S108). Here, the number of ranks counted may be the total number of the ranks counted by the counting means 406 or the number for each rank. In the embodiment of the present invention, the total number of ranks will be described below.

  As a result of the determination, if the counted number of ranks does not exceed the first predetermined number of times (FIG. 5: S108 NO), the counting means 406 ends the process. In this case, since it is impossible to detect whether the paper feed roller 117 is worn or whether the paper transport is delayed, the counting means 406 continues for each paper transport. The calculated sheet conveyance time difference Te is ranked and the number of ranks is counted.

  By the way, since the image forming unit 402 continuously performs image formation (FIG. 5: S101), after the ranking table 600 is created, the measuring unit 403 performs the same as described above. The actually measured transport time Tr is measured (FIG. 5: S102), and the first determination unit 404 calculates the sheet transport time difference Te using the actually measured transport time Tr (FIG. 5: S103).

  Here, since the ranking table 600 exists, the first determination unit 404 notifies the count unit 406 to that effect, and the count unit 406 that has received the notification, as described above, Based on the division table 600, the sheet transport time difference Te is ranked, and 1 is added to the number of ranked ranks and counted.

  As a result of the above-described image formation being repeated, the number of the counted ranks increases, and when the number of the counted ranks exceeds the first predetermined number as a result of the determination in S108 (FIG. 5: S108 YES) The counting unit 406 notifies the second determination unit 407 to that effect. The second determination unit 407 that has received the notification determines whether or not the length of the actually measured transport time Tr for each transport of each sheet is continuously increased (FIG. 5: S109).

  Any method may be used as the second determination unit 407 to determine whether or not the length of the actually measured transport time Tr for each sheet transport is continuously increased. It is determined whether or not the number of ranks A ranked in the smallest difference range 601 among the ranks 602 of the division table 600 does not exceed the second predetermined number of times (for example, four times).

  Here, as shown in FIG. 6A, when the rank classification table 600 is created due to a single paper conveyance delay, the actually measured conveyance time Tr for each subsequent paper conveyance is substantially equal to the standard conveyance. Rank A assigned to the smallest difference range 601 occupies most of the ranks of the paper conveyance time difference Te corresponding to the time Ts. That is, as shown in FIG. 7A, the number of ranks D attached to the first paper transport time difference Te is 1, and the number of ranks A attached to the paper transport time difference Te for each subsequent paper transport is 5 In this case, the second determination means 407 determines that the number of ranks A ranked in the smallest difference range 601 has exceeded the second predetermined number of times (FIG. 5: S109 NO), and the number of ranks Is determined not to increase continuously. In this case, since the above-described single paper conveyance delay has occurred and the paper conveyance is not delayed due to wear of the paper feed roller 117, the second determination means 407 This is notified to the erasing unit 408, and the erasing unit 408 erases the ranking table 600 including the counted number (FIG. 5: S112).

  As a result, it is not necessary to store the ranking table 600 permanently in a predetermined memory, and the ranking table 600 is stored in the predetermined memory only when it is considered that the feed roller 117 is worn. Since it will suffice if it is stored, the memory can be used effectively.

  On the other hand, as shown in FIG. 7B, the outer diameter of the paper feed roller 117 gradually decreases, and accordingly, the conveyance of the paper is continuously delayed little by little, and the paper corresponding to the conveyance of the paper When the transport time difference Te is continuously increased, the rank given to the paper transport time difference Te is gradually increased as the number of subsequent paper transports increases. Therefore, the counting unit 406 does not increase the number of ranks A ranked in the smallest difference range 601 and ranks in the next smallest difference range 601 as the number of subsequent sheet conveyances increases. The number of ranks B and the number of ranks C ranked in the third smallest difference range 601 are increased. That is, as shown in FIG. 8A, the number of ranks B attached to the first predetermined number of paper transport time differences Te is 3, and the number of ranks C attached to the subsequent predetermined number of paper transport time differences Te. Becomes 3. In this case, the second determination means 407 determines that the number of ranks A ranked in the smallest difference range 601 does not exceed the second predetermined number of times (FIG. 5: S109 YES), and the number of ranks Is determined to have increased continuously. In this case, since there is a delay in continuous paper conveyance due to the above-described wear of the paper feed roller, the second determination unit 407 notifies the detection unit 409 to that effect and receives the notification. The detecting means 409 detects that the paper feed roller 117 is worn when it is determined that the number of ranks has continuously increased.

  In FIG. 8A, it is assumed that the rank of the difference range 601 is gradually increased as the number of subsequent sheet conveyances increases. For example, because the difference range 601 is fine, When ranks B, C, B, C, B, C and ranks B and C appear alternately, ranks C, C, C, B, B, B and rank C appear first, and rank B It is also assumed that it appears. In this case, even if the second determination unit 407 determines whether or not the number of ranks A ranked in the smallest difference range 601 does not exceed the second predetermined number of times, the sheet feeding roller 117 is really not. It may not be possible to determine that the number of ranks has continuously increased due to wear. In this case, for example, although the amount of data increases, the second determination unit 407 counts the number of ranks of the actually measured transport time Tr calculated for each transport of each sheet and the order in which the count is started. Are associated with each other, and it is determined whether the higher rank is associated with the increase in the order. If the higher rank is associated with the increase in the order, the second determination unit 407 Further, it may be determined that the number of ranks continuously increases due to wear of the paper feed roller 117. In this case, the second determination unit 407 includes a first determination process for determining whether the number of ranks A ranked in the smallest difference range 601 does not exceed the second predetermined number of times, As the number increases, either the second determination process for determining whether or not a higher rank is associated may be executed, or both may be executed.

  Here, any processing may be executed after the detection means 409 detects that the paper feed roller 117 is worn. For example, as processing when the paper feed roller 117 is worn out, processing for increasing the pressing force with which the paper feed roller 117 presses the paper, processing for increasing the rotational speed of the paper feed roller 117, and the paper feed roller 117 In response to the measured transport time Tr caused by the wear of the paper, the image forming speed (printing process) controlled by the image forming unit 402 is slowed down, and the process of notifying the wear of the paper feed roller 117 (screen display, warning sound) Occurrence etc.).

  Hereinafter, a screen display for informing the wear of the paper feed roller 117 will be described as an example. That is, the detection unit 409 displays an exchange screen for exchanging the paper feed roller 117 on the touch panel 201 via the display receiving unit 401 (FIG. 5: S110).

  In the replacement screen 800, as shown in FIG. 8B, a message 801 that the paper feed roller 117 is worn, a message 802 that prompts the user to replace the paper feed roller 117, and a serviceman. The contact information 803 is displayed.

  Accordingly, the user can surely grasp the wear of the paper feed roller 117, and can smoothly exchange the paper feed roller 117. Since there are a plurality of paper feed rollers 117 depending on the paper size, the replacement screen 800 may display the identification number of the paper feed roller 117, the paper size, and the like.

  When the user replaces the worn paper feed roller 117 with a new paper feed roller 117 and completes the exchange (FIG. 5: S111). The detection means 409 detects this and notifies the erasure means 408 to that effect. Upon receipt of the notification, the erasing unit 408 erases the ranking table 600 including the counted number as described above (FIG. 5: S111).

  Thereby, after the replacement of the paper feed roller 117, the paper transport time difference Te does not increase stepwise, so that it is not necessary to keep the rank table 600 stored in a predetermined memory. By erasing the table 600, the memory can be effectively used.

  As described above, in the present invention, the first determination unit 404 that determines whether or not the actually measured transport time Tr exceeds the reference transport time Ts calculated using the unworn paper feed roller 117, As a result of the determination, when the measured transport time Tr exceeds the reference transport time Ts, the rank classification table 600 that ranks the length of the measured transport time Tr in stages is used for each transport of each sheet. Count unit 406 for counting the number of ranks of the actually measured transport time Tr to be calculated, and whether or not the length of the actually measured transport time Tr for each paper transport is continuously increased based on the result of the number of ranks. A second determination unit 407 for determining whether or not the number of ranks has increased continuously as a result of the determination, and a detection unit 409 for detecting that the feed roller 117 is worn. Prepare And wherein the door.

  Accordingly, it is possible to accurately determine the wear of the paper feed roller 117 by determining whether the paper conveyance delay is single or continuous, and accurately grasping the form of wear of the paper feed roller 117. It becomes possible.

  In the embodiment of the present invention, the creation unit 405 is provided. However, if there is a margin in the memory for storing the ranking table 600, the creation unit 405 is omitted and preset. The rank classification table 600 is stored in a predetermined memory, and the counting means 406 uses the rank classification table 600 to transfer each sheet when the measured conveyance time Tr exceeds the reference conveyance time Ts. It may be configured to count the number of ranks of the actually measured transport time Tr calculated in (1).

  In the embodiment of the present invention, the second determination unit 407 determines whether the number of ranks A ranked in the smallest difference range 601 does not exceed the second predetermined number of times. The configuration of For example, the second determination unit 407 calculates the ratio of the rank A, and determines whether the calculated ratio of the rank A does not exceed a third predetermined ratio (for example, 50%). Also good. Also, a predetermined weighting factor is prepared in advance for each rank (for example, rank A is 1.0, rank B is 1.5, rank C is 1.5, rank D is 1.0), The second determination means 407 calculates a multiplication number for each rank obtained by multiplying the number for each rank by a weighting factor for each corresponding rank, and the multiplication number for the rank A is a fourth predetermined value ( For example, it may be determined whether or not 3) is not exceeded.

  On the other hand, from another viewpoint, the second determination unit 407 determines whether the number of ranks B ranked in the next smallest difference range 601 exceeds the second predetermined number or the third smallest. It may be configured to determine whether or not the number of ranks C ranked in the difference range 601 exceeds the second predetermined number. The number of ranks B and C may be changed to the above-described ratio and multiplication number.

  In the embodiment of the present invention, the erasing unit 408 is configured to delete the ranking table 600, but other configurations may be used. For example, the counting unit 406 may be configured to restart counting while leaving only a part of the number of ranks associated with the ranking table 600. Here, a part of the remaining ranking table 600 is, for example, only the number of ranks (for example, rank C) next to the rank (for example, rank B) having the largest number of ranks in the ranking table 600. Only the associated rank division table 600 or the rank ratio data of the rank division table 600 is the data. A part of the remaining ranking table 600 can be very useful information when a user such as an administrator analyzes the wear of the paper feed roller 117.

In the embodiment of the present invention, the MFP 100 is configured to include each unit. However, a program that realizes each unit may be stored in a storage medium, and the storage medium may be provided. In this configuration, the above-described program is read by the multi-function device 100, and the multi-function device 100 implements the above-described means. In that case, the program itself read from the Symbol 憶 medium effects of the present invention. Furthermore, it is possible to provide a method for storing the steps executed by each means in a hard disk.

  As described above, the image forming apparatus and the feed roller wear detection method according to the present invention are useful not only for multifunction peripherals but also for copying machines, printers, and the like. The present invention is effective as an image forming apparatus and a feed roller wear detection method capable of accurately detecting the wear of the feed roller.

DESCRIPTION OF SYMBOLS 100 MFP 401 Display reception means 402 Image formation means 403 Measurement means 404 First determination means 405 Creation means 406 Count means 407 Second determination means 408 Erase means 409 Detection means

Claims (8)

In the image forming apparatus for detecting wear of the paper feed roller by measuring an actual transport time required for transporting the paper in a predetermined section when the paper is transported by the paper feed roller,
A first determination means for determining whether or not the measured transport time exceeds a reference transport time calculated using an unworn paper feed roller;
As a result of the determination, when the measured transport time exceeds the reference transport time, it is calculated for each sheet transport using a ranking table that ranks the length of the actually measured transport time stepwise. Counting means for counting the number of ranks of the actually measured transport time;
Second determination means for determining whether or not the length of the actually measured conveyance time for each conveyance of each sheet is continuously increased based on the result of the number of ranks;
An image forming apparatus comprising: a detection unit configured to detect that the feed roller is worn when it is determined that the number of ranks has continuously increased as a result of the determination. Creating means for creating the ranking table when the measured transport time exceeds the reference transport time;
The image forming apparatus according to claim 1, further comprising: an erasing unit that erases the ranking table when it is determined that the number of ranks does not continuously increase. The first determination means subtracts the reference transport time from the measured transport time, calculates the subtracted value as a paper transport time difference, and whether or not the paper transport time difference exceeds a preset threshold value. The image forming apparatus according to claim 1, wherein it is determined whether or not the measured transport time exceeds the reference transport time. The image forming apparatus according to claim 3, wherein the ranking table is a ranking table in which a difference range in which the threshold value is increased step by step and a rank indicating the size of the difference range are associated with each other. The second determination means determines whether or not the number of ranks A ranked in the smallest difference range among the ranks of the ranking table does not exceed a predetermined number of times. The image forming apparatus according to claim 4, wherein it is determined whether or not the length of the actually measured conveyance time is continuously increased. In the paper feed roller wear detection method for detecting wear of the paper feed roller by measuring the actual transport time required for transporting the paper in a predetermined section when the paper is transported by the paper feed roller,
A first determination step for determining whether or not the measured transport time exceeds a reference transport time calculated using an unworn paper feed roller;
As a result of the determination, when the measured transport time exceeds the reference transport time, it is calculated for each sheet transport using a ranking table that ranks the length of the actually measured transport time stepwise. A counting step for counting the number of ranks of the actually measured transport time;
A second determination step of determining whether or not the length of the actually measured conveyance time for each conveyance of each sheet is continuously increased based on the result of the number of ranks;
And a detection step of detecting that the feed roller is worn when it is determined that the number of ranks has increased continuously as a result of the determination.   A program for causing a computer to execute the paper feed roller wear detection method according to claim 6. A computer-readable storage medium,
Serial憶媒body storing a program of claim 7.

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