Image forming apparatus, component state detection method, and component state detection program

Abstract

To detect the state of an object, a state of which is changed by use while driving the object.SOLUTION: An image forming apparatus includes: a first motor for driving a paper feeding roller; a load detection part 71 for detecting a load received by the first motor; and a state detection part 77 for detecting a state of an object on the basis of a history of driving of the paper feeding roller by the first motor and a change amount of the load received by the first motor.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to an image forming apparatus, a member state detection method, and a member state detection program, and particularly relates to an image forming apparatus provided with a member whose state changes through use, a member state detection method executed by the image forming apparatus, and a member state detection program that causes a computer controlling the image forming apparatus to execute the member state detection method. Background Art

[0002] Among members included in image forming apparatuses such as copying machines, printers, and facsimile devices, some members become soiled or worn out through forming images on recording media. These members require cleaning or replacement at predetermined timing. For this reason, such members are cleaned or replaced by specialized personnel who perform maintenance on image forming apparatuses. However, if a non-specialized user can also clean or replace the member, the need for specialized maintenance personnel is eliminated.

[0003] For example, Japanese Patent Application Laid-Open No. 2008-225221 discloses an image forming apparatus where an apparatus control unit rotates a fixing roller at a predetermined timing at a rotation speed that is higher than the rotation speed during a printing process by a preset constant speed, detects the load torque of a motor 274, which is the drive source of the fixing roller at this time, using a load torque detection unit 275, and determines the degree of contamination of a metal roller, which is a cleaning member for a pressure roller, based on the detected load torque during high-speed rotation.

[0004] However, the image forming apparatus described in Japanese Patent Application Laid-Open No. 2008-225221 must rotate the roller at a speed higher than the rotation speed during printing by the preset constant speed, and has to execute a process separate from the printing process. Prior Art Documents Patent Documents

[0005] Patent Document 1 Japanese Patent Publication No. 2008-225221 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] One of the objectives of this invention is to provide an image forming apparatus capable of detecting the state of an object whose state changes with use, while driving the object.

[0007] Another object of this invention is to provide a component state detection method that can detect the state of an object whose state changes due to use while the object is being driven.

[0008] Another object of this invention is to provide a component state detection program that can detect the state of an object whose state changes due to use, while the object is being driven. [Means for solving the problem]

[0009] According to one aspect of this invention, an image forming apparatus includes a drive source for driving an object, a load detection unit for detecting the load on the drive source, and a history of the object being driven by the drive source. If the value exceeds a predetermined tolerance threshold, the first load detected at the first time and the second load detected at the second time, which is after the first time, It comprises a state detection unit that detects the state of an object based on the above, and

[0010] According to another aspect of this invention, a member state determination method is a member state detection method performed in an image forming apparatus equipped with a drive source for driving an object, comprising a load detection step for detecting the load received by the drive source, and a history of the object being driven by the drive source. If the value exceeds a predetermined tolerance threshold, the first load detected at the first time and the second load detected at the second time, which is after the first time, The system includes a state detection step that detects the state of an object based on the above.

[0011] According to another aspect of this invention, the member state determination program is a member state detection method performed in an image forming apparatus equipped with a drive source for driving an object, comprising: a load detection step for detecting the load on the drive source, and a history of the object being driven by the drive source. If the value exceeds a predetermined tolerance threshold, the first load detected at the first time and the second load detected at the second time, which is after the first time,causing a computer to execute a state detection step of detecting the state of an object based on BRIEF DESCRIPTION OF THE DRAWINGS

[0012] [Figure 1] FIG. 1 is a first perspective view showing an external appearance of a printer according to one embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing an example of the hardware configuration of the printer. [Figure 3] FIG. 3 is a cross-sectional view schematically showing an example of the internal structure of the printer. [Figure 4] FIG. 4 is a diagram showing an example of transmission of driving force to a roller. [Figure 5] FIG. 5 is a schematic diagram for explaining the function of a separating roller. [Figure 6] FIG. 6 is a diagram showing an example of torque current ripple. [Figure 7] FIG. 7 is a block diagram showing an example of functions of a CPU included in the printer. [Figure 8] FIG. 8 is a flowchart showing an example of the flow of component state detection processing. [Figure 9] FIG. 9 is a flowchart showing an example of the flow of load detection processing. [Figure 10] FIG. 10 is a flowchart showing an example of the flow of discrimination processing. [Figure 11] FIG. 11 is a diagram showing an example of experimental data. [Figure 12] FIG. 12 is a cross-sectional view of a fixing device. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[0014] <First Embodiment> FIG. 1 is a first perspective view showing the appearance of a printer according to one embodiment of the present invention. FIG. 2 is a block diagram showing an example of the hardware configuration of the printer. Referring to FIGS. 1 and 2, the printer 100 is an example of an image forming apparatus, and includes a main circuit 110, an image forming unit 140 for forming an image on a recording medium based on image data, a paper feeding unit 150 for feeding paper to the image forming unit 140, and an operation panel 160 serving as a user interface. The recording medium includes, in addition to paper, OHP sheets formed of resin, cloth, and the like. Hereinafter, description will be given taking paper as an example of the recording medium.

[0015] The main circuit 110 includes a CPU (Central Processing Unit) 111 that controls the entire printer 100, a communication interface (I / F) unit 112, a ROM (Read Only Memory) 113, a RAM (Random Access Memory) 114, a hard disk drive (HDD) 115 serving as a large-capacity storage device, and an external storage device 117. The CPU 111 is connected to the image forming unit 140, the paper feeding unit 150, and the operation panel 160, and controls the entire printer 100.

[0016] The paper feeding unit 150 conveys a recording medium such as paper stored in a paper feed cassette to the image forming unit 140. A housing of the printer 100 is provided with a door 150A. The door 150A is openable and closable. In a closed state, the door 150A covers a part of a paper conveyance path of the paper feeding unit 150, and in an open state, a part of the conveyance path is exposed to the outside. A sensor for detecting opening and closing of the door 150A is provided.

[0017] The image forming unit 140 is controlled by the CPU 111 and forms an image by a well-known electrophotographic method. The image forming unit 140 forms an image on a recording medium conveyed by the paper feeding unit 150 based on image data input from the CPU 111, and discharges the paper on which the image is formed to a paper discharge tray 39. The image data output by the CPU 111 to the image forming unit 140 includes image data such as print data received from an external personal computer or the like.

[0018] ROM113 stores the program that the CPU111 executes, or the data necessary to execute that program. RAM114 is used as a workspace when the CPU111 executes the program.

[0019] The control panel 160 is located on the top surface of the printer 100. The control panel 160 includes a display unit 161 and an operation unit 163. The display unit 161 is, for example, a liquid crystal display (LCD) and displays instruction menus for the user, information about acquired image data, etc. Instead of an LCD, any device that can display images, such as an organic electroluminescent (EL) display, can be used.

[0020] The operation unit 163 includes a touch panel 165 and a hard key unit 167. The hard key unit 167 includes a plurality of hard keys, which are, for example, contact switches. The touch panel 165 detects the position indicated by the user on the display surface of the display unit 161.

[0021] The communication interface unit 112 is an interface for connecting the printer 100 to the network. The communication interface unit 112 communicates with other computers connected to the network using communication protocols such as TCP (Transmission Control Protocol) or UDP (User Datagram Protocol). The network to which the communication interface unit 112 is connected is a local area network (LAN), and the connection method can be wired or wireless. Furthermore, the network is not limited to a LAN; it may also be a wide area network (WAN), public switched telephone network (PSTN), the internet, etc.

[0022] The external storage device 117 is controlled by the CPU 111 and is equipped with a CD-ROM (Compact Disk Read Only Memory) 118 or semiconductor memory. In this embodiment, an example is described in which the CPU 111 executes a program stored in the ROM 113, but the CPU 111 may also control the external storage device 117 to read a program for execution from the CD-ROM 118, store the read program in the RAM 114, and then execute it.

[0023] Furthermore, the recording medium for storing the program to be executed by the CPU 111 is not limited to the CD-ROM 118, but may also be a flexible disk, cassette tape, optical disk (MO (Magnetic Optical Disc) / MD (Mini Disc) / DVD (Digital Versatile Disc)), IC card, optical card, mask ROM, EPROM (Erasable Programmable ROM), or other semiconductor memory. In addition, the CPU 111 may download the program from a computer connected to the network and store it in the HDD 115, or a computer connected to the network may write the program to the HDD 115, load the program stored in the HDD 115 into the RAM 114, and execute it with the CPU 111. The program referred to here includes not only programs that can be directly executed by the CPU 111, but also source programs, compressed programs, encrypted programs, etc.

[0024] Figure 3 is a schematic cross-sectional view showing an example of the internal structure of a printer. For the purposes of this explanation, the left-right direction in Figure 3 will be referred to as the left-right direction, and the front-back direction will be referred to as the depth direction. In the left-right direction, the direction from left to right will be referred to as the right side direction, and the direction from right to left will be referred to as the left side direction. In the depth direction, the direction from front to back will be referred to as the front direction, and the direction from back to front will be referred to as the back direction.

[0025] Printer 100 is equipped with image forming units 20Y, 20M, 20C, and 20K for yellow, magenta, cyan, and black, respectively. Here, "Y", "M", "C", and "K" represent yellow, magenta, cyan, and black, respectively. An image is formed when at least one of the image forming units 20Y, 20M, 20C, and 20K is driven. A full-color image is formed when all of the image forming units 20Y, 20M, 20C, and 20K are driven. Printing data for yellow, magenta, cyan, and black are input to the image forming units 20Y, 20M, 20C, and 20K, respectively. The only difference between the image forming units 20Y, 20M, 20C, and 20K is the color of the toner they handle, so here we will describe the image forming unit 20Y for forming a yellow image.

[0026] The image forming unit 20Y includes an exposure device 21Y into which yellow printing data is input, a photoreceptor drum 23Y which is an image carrier, a charging roller 22Y for uniformly charging the surface of the photoreceptor drum 23Y, a developer 24Y, a primary transfer roller 25Y for transferring the toner image formed on the photoreceptor drum 23Y onto an intermediate transfer belt 30 which is an image carrier by the action of an electric field, a drum cleaning blade 27Y for removing residual toner from the photoreceptor drum 23Y, a toner bottle 41Y, and a toner hopper 42Y.

[0027] The toner bottle 41Y contains yellow toner. The toner bottle 41Y rotates using a toner bottle motor as its drive source and discharges toner to the outside. The toner discharged from the toner bottle 41Y is supplied to the toner hopper 42Y. The toner hopper 42Y supplies toner to the developer unit 24Y in accordance with the amount of toner remaining in the developer unit 24Y, which falls below a predetermined lower limit.

[0028] Around the photoreceptor drum 23Y, the charging roller 22Y, exposure unit 21Y, developer unit 24Y, primary transfer roller 25Y, and drum cleaning blade 27Y are arranged in order along the rotational direction of the photoreceptor drum 23Y.

[0029] The photoreceptor drum 23Y is charged by the charging roller 22Y, and then irradiated with laser light emitted by the exposure device 21Y. The exposure device 21Y exposes the image-corresponding portion of the surface of the photoreceptor drum 23Y to form an electrostatic latent image. This forms an electrostatic latent image on the photoreceptor drum 23Y. Subsequently, the developer 24Y develops the electrostatic latent image formed on the photoreceptor drum 23Y with charged toner. Specifically, toner is placed on the electrostatic latent image formed on the photoreceptor drum 23Y by the action of an electric field force, thereby forming a toner image on the photoreceptor drum 23Y. The toner image formed on the photoreceptor drum 23Y is transferred onto the intermediate transfer belt 30, which is an image carrier, by the action of an electric field force using the primary transfer roller 25Y. Toner that remains on the photoreceptor drum 23Y without being transferred is removed from the photoreceptor drum 23Y by the drum cleaning blade 27Y.

[0030] Meanwhile, the intermediate transfer belt 30 is suspended by the drive roller 33 and the driven roller 34 to prevent slack. When the drive roller 33 rotates counterclockwise in Figure 2, the intermediate transfer belt 30 rotates counterclockwise in the figure at a predetermined speed. As the intermediate transfer belt 30 rotates, the driven roller 34 rotates counterclockwise.

[0031] As a result, the image forming units 20Y, 20M, 20C, and 20K sequentially transfer toner images onto the intermediate transfer belt 30. The timing at which each of the image forming units 20Y, 20M, 20C, and 20K transfers toner images onto the intermediate transfer belt 30 is adjusted by detecting reference marks attached to the intermediate transfer belt 30. In this way, yellow, magenta, cyan, and black toner images are superimposed on the intermediate transfer belt 30.

[0032] The toner image formed on the intermediate transfer belt 30 is transferred to the paper by the action of an electric field force by the secondary transfer roller 26, which is a transfer member. The paper, which is transported by the timing roller 31, is transported to the nip section where the intermediate transfer belt 30 and the secondary transfer roller 26 come into contact. The paper on which the toner image has been transferred is transported to the fuser unit 50, where it is heated and pressurized. This melts the toner and fixes it to the paper. After that, the paper is discharged into the output tray 39.

[0033] A belt cleaning blade 28 is provided upstream of the image forming unit 20Y of the intermediate transfer belt 30. The belt cleaning blade 28 removes toner that remains on the intermediate transfer belt 30 without being transferred to the paper.

[0034] When forming a full-color image, the printer 100 drives all of the image forming units 20Y, 20M, 20C, and 20K. However, when forming a monochrome image, it drives only one of the image forming units 20Y, 20M, 20C, and 20K. It is also possible to form an image by combining two or more of the image forming units 20Y, 20M, 20C, and 20K. Here, we describe an example in which the printer 100 employs a tandem system equipped with image forming units 20Y, 20M, 20C, and 20K, each forming one of the four colors of toner on the paper. However, a four-cycle system in which one photosensitive drum transfers the four colors of toner sequentially to the paper may also be used.

[0035] Multiple sheets of paper are loaded into the paper feed cassette 35. The pickup roller PR1, paper feed roller FR1, and paper separation roller SR1 are positioned in conjunction with the paper feed cassette 35. The pickup roller PR1 picks up the top sheet of paper from the multiple sheets in the paper feed cassette 35 and supplies it to the paper feed roller FR1. The paper feed roller FR1 then feeds the paper from the pickup roller PR1 to the transport roller 37. The transport rollers 37 then transport the paper from the paper feed roller FR1 to the timing roller 31. The function of the paper separation roller SR1 will be described later.

[0036] In addition, a pickup roller PR2, a paper feed roller FR2, and a paper separation roller SR2 are positioned to accommodate the manual feed cassette 35A. When one or more sheets of paper are loaded into the manual feed cassette 35A, the pickup roller PR2 picks up the top sheet of paper from the one or more sheets placed in the manual feed cassette 35A and supplies it to the paper feed roller FR2. The paper feed roller FR2 sends the paper transported from the pickup roller PR2 to the transport roller 37. The transport roller 37 transports the paper sent from the paper feed roller FR2 to the timing roller 31. The function of the paper separation roller SR2 will be described later.

[0037] The paper transport path includes an image forming path 45, a first transport path 46, a second transport path 47, and a front-to-back inversion path 48. The image forming path 45 is the path from the timing roller 31 to the path switching gate 49, and the secondary transfer roller 26 and the fuser 50 are arranged in order from the timing roller 31. The timing roller 31 feeds the paper transported from the paper feed cassette 35 or the manual feed cassette 35A into the image forming path 45. The timing roller 31 starts transporting the paper so that the paper reaches the secondary transfer roller 26 at the same time that the toner image formed on the intermediate transfer belt 30 reaches the secondary transfer roller 26. The paper transported by the timing roller 31 is pressed against the intermediate transfer belt 30 by the secondary transfer roller 26, and the yellow, magenta, cyan, and black toner images superimposed on the intermediate transfer belt 30 are transferred to the paper.

[0038] The paper transported from the secondary transfer roller 26 is transported to the fuser unit 50. The fuser unit 50 heats and pressurizes the paper. This fixes the toner to the paper. After that, the paper is transported to either the first transport path 46 or the second transport path 47 by the path switching gate 49.

[0039] The first transport path 46 is the path from the path switching gate 49 to the paper output roller 43. Paper transported along the first transport path 46 is ejected into the paper output tray 39 by the paper output roller 43.

[0040] The second transport path 47 is the path from the path switching gate 49 to the reversing roller 44. At the path switching gate 49, the second transport path 47 connects to the image forming path 45 and the front / back reversal path 48. Paper entering the second transport path 47 from the path switching gate 49 is transported to the reversing roller 44. The reversing roller 44 performs three operations: standby operation, reversing operation, and paper ejection operation. When the reversing roller 44 is in standby operation, it rotates forward and stops after a predetermined time has elapsed since the timing roller 31 was driven. As a result, the reversing roller 44 holds the paper entering from the path switching gate 49 with its rear end having passed the path switching gate 49. After the standby operation, the reversing roller 44 performs the reversing operation. When the reversing roller 44 performs the reversing operation, it rotates in reverse and transports the held paper back to the path switching gate 49. As a result, the paper is transported along the second transport path 47 by the reversing roller 44 and guided to the front / back reversal path 48 by the path switching gate 49. When the reversing roller 44 is performing an ejection operation, it rotates forward to eject the paper into the paper output tray 39.

[0041] The front-to-back inversion path 48 is a path connecting the path switching gate 49 and the timing roller 31 in the image forming path 45. Paper entering the front-to-back inversion path 48 from the path switching gate 49 is transported to the timing roller 31 by the transport roller 38. Therefore, an image is formed on the front surface of the paper as it first passes through the image forming path 45, and then an image is formed on the back surface of the paper as it passes through the image forming path 45 again via the front-to-back inversion path 48. Paper with an image formed on the back surface is guided to the first transport path 46 by the path switching gate 49 and ejected into the output tray 39.

[0042] Figure 4 shows an example of how driving force is transmitted to the rollers. Referring to Figure 4, a first motor M1 is provided that transmits rotational force to the pickup roller PR1 and the paper feed roller FR1, which are provided in accordance with the paper feed cassette 35. The rotation shaft of the first motor M1 is connected to the rotation shaft of the paper feed roller FR1 via a belt. The rotation shaft of the paper feed roller FR1 is connected to the rotation shaft of the pickup roller PR1 via a belt. The first motor M1 is current-controlled by the first motor control unit MC1. The first motor control unit MC1 detects the rotational speed of the first motor M1 and performs feedback control to maintain the rotational speed of the first motor M1 at a predetermined value by controlling the current value. The first motor control unit MC1 outputs the current value of the current flowing through the first motor M1 to the CPU 111. When the first motor control unit MC1 drives the first motor M1, the paper feed roller FR1 and the pickup roller PR1 rotate simultaneously. The paper feed roller FR1 and the pickup roller PR1 receive rotational force transmitted from the first motor M1 and rotate in the direction indicated by arrow a1 in the figure. No power is transmitted to the paper shuffling roller SR1 from the first motor M1.

[0043] As the pickup roller PR1 rotates, the uppermost sheet of paper Pa1, which is in contact with the pickup roller PR1, is transported to the paper feed roller FR1. At this time, sheet of paper Pa2, which is in contact with sheet Pa1, may be transported to the paper feed roller FR1 overlapping with sheet Pa1. The sorting roller SR1 has the function of restricting the transport of this sheet of paper Pa2 to the paper feed roller FR1.

[0044] Figure 5 is a schematic diagram illustrating the function of the paper handling rollers. Referring to Figure 5, the case in which paper Pa1 and paper Pa2 overlapping paper Pa1 are transported from the pickup roller PR1 to the paper feed roller FR1 is shown.

[0045] The paper separation roller SR1 is positioned opposite the paper feed roller FR1. The axis of rotation of the paper separation roller SR1 is biased by a spring SP in the direction indicated by arrow a4. Arrow a4 is in the direction from the paper separation roller SR1 to the paper feed roller FR1. When there is no paper between the paper feed roller FR1 and the paper separation roller SR1, the paper separation roller SR1 is in contact with the paper feed roller FR1 and rotates in conjunction with the rotation of the paper feed roller FR1. However, the paper feed roller FR1 is equipped with a resistance to restrict its rotation.

[0046] In Figure 5, the area enclosed by the dashed line is magnified and schematically shown in the callout region. The coefficient of friction is shown when multiple sheets of paper are inserted between the paper feed roller FR1 and the paper separation roller SR1. Let μ1 be the dynamic coefficient of friction between the paper feed roller FR1 and paper Pa1, μ2 be the static coefficient of friction between the paper separation roller SR1 and paper Pa2, and μ3 be the static coefficient of friction between paper Pa1 and paper Pa2. The outer surfaces of the paper feed roller FR1 and the paper separation roller SR1 are made of a material that satisfies the relationships μ1 > μ3 and μ2 > μ3, and are surface-treated.

[0047] When multiple sheets of paper are inserted between the feed roller FR1 and the separation roller SR1, the feed roller FR1 has a resistance that restricts its rotation, so a force is generated in the direction indicated by arrow a3. Since μ2 > μ3, the separation roller SR1 stops without rotating while in contact with the paper Pa2.

[0048] Furthermore, since μ1 > μ3, the force that the paper feed roller FR1 applies to the paper Pa1 overcomes the frictional force that the paper Pa1 experiences from the paper Pa2, and the paper Pa1 is transported in the direction indicated by arrow a5.

[0049] Returning to Figure 4, the paper transported by the paper feed roller FR1 is transported along the transport path shown by the thick solid line in the figure and is transported to the transport roller 37. In the transport path, a paper detection sensor SE1 is positioned between the paper feed roller FR1 and the transport roller 37. The paper detection sensor SE1 is a photoelectric sensor and comprises a light-emitting part that emits light and a light-receiving part that receives light. The light-emitting part and the light-receiving part are positioned on either side of the transport path, and a detection area is defined between the light-emitting part and the light-receiving part in the transport path. When the paper being transported along the transport path passes through the detection area, it is detected that the light-receiving part no longer receives the light emitted by the light-emitting part.

[0050] The rotating shaft of the first motor M1 is further connected via a belt to the rotating shaft of the paper feed roller FR2, which is provided in accordance with the manual feed cassette 35A. An electromagnetic clutch is provided on the rotating shaft of the first motor M1, which can be switched to transmit power to either the paper feed roller FR1 or the paper feed roller FR2.

[0051] Therefore, when the first motor M1 is driven, the paper feed roller FR2 rotates. The paper feed roller FR2 receives rotational force transmitted from the first motor M1 and rotates in the direction indicated by arrow a2 in the figure. Power is not transmitted from the first motor M1 to the shuffling roller SR2 and the pickup roller.

[0052] The paper placed in the manual feed cassette 35A is positioned so that the top sheet of paper is in contact with the paper feed roller FR2. As a result, the rotation of the paper feed roller FR2 transports the top sheet of paper to the transport roller 37. The function of the sorting roller SR2 is the same as that of the sorting roller SR1 described above. Therefore, the explanation will not be repeated here. A paper detection sensor SE2 is positioned between the paper feed roller FR2 and the transport roller 37 in the transport path.

[0053] A transport roller 37 is positioned between the paper feed rollers FR1 and FR2 and the timing roller 31. The transport roller 37 has an active roller and a driven roller. The active roller and the driven roller face each other. A second motor M2 is provided to transmit rotational force to the active roller. The rotation shaft of the second motor M2 is connected to the rotation shaft of the active roller via a belt. No power is transmitted to the driven roller from the second motor M2. The second motor M2 is current-controlled by a second motor control unit MC2. The second motor control unit MC2 detects the rotational speed of the second motor M2 and performs feedback control to maintain the rotational speed of the second motor M2 at a predetermined value by controlling the current value. The second motor control unit MC2 outputs the current value of the current flowing to the second motor M2 to the CPU 111. When the second motor control unit MC2 drives the second motor M2, the active roller rotates, and the driven roller rotates in conjunction with the rotation of the active roller.

[0054] A driven timing roller 31A is positioned opposite the timing roller 31. A third motor M3 is provided to transmit rotational force to the timing roller 31. The rotation axis of the third motor M3 is connected to the rotation axis of the timing roller 31 via a belt. No power is transmitted to the driven timing roller 31A from the third motor M3. The third motor M3 is current-controlled by the third motor control unit MC3. The third motor control unit MC3 detects the rotational speed of the third motor M3 and performs feedback control to maintain the rotational speed of the third motor M3 at a predetermined value by controlling the current value. The third motor control unit MC3 outputs the current value of the current flowing to the third motor to the CPU 111. When the third motor control unit MC3 drives the third motor M3, the timing roller 31 rotates, and the driven timing roller 31A rotates in conjunction with the rotation of the timing roller 31.

[0055] In the transport path, two paper detection sensors SE3 and SE4 are positioned between the timing roller 31 and the transport roller 37. The transport roller 37, paper detection sensor SE3, paper detection sensor SE4, and timing roller 31 are arranged in that order. The second motor M2 and the third motor M3 are driven according to the timing when the two paper detection sensors SE3 and SE4 detect paper, respectively. Specifically, the transport roller 37 stops when the leading edge of the paper reaches the timing roller 31 while the timing roller 31 is stopped, and the paper has been transported a predetermined distance. As a result, the paper is bent in the transport path, and the leading edge of the paper becomes parallel to the timing roller 31 while the paper is pressed against it. Therefore, the direction in which the paper is transported is aligned with the direction of the timing roller 31 before the timing roller 31 starts rotating.

[0056] The first motor M1 rotates the paper feed roller FR1 and the pickup roller PR1 simultaneously. The pickup roller PR1 has multiple protrusions arranged at predetermined intervals in the circumferential direction on its outer surface. The multiple sheets of paper stored in the paper feed cassette 35 are biased from below upward by an elastic member such as a spring. Therefore, the pickup roller PR1 receives an upward force from the paper. Since the pickup roller PR1 has multiple protrusions on its outer surface, the protrusions strike the top sheet of paper. Therefore, it is easier to transport the top sheet of paper.

[0057] On the other hand, the paper feed roller FR1 receives power from the first motor M1. The paper feed roller FR1 has a textured outer surface to increase its dynamic friction coefficient μ1. When paper dust adheres to the surface of the paper feed roller FR1, the dynamic friction coefficient μ1 becomes smaller compared to when no paper dust adheres to the surface. When the dynamic friction coefficient μ1 decreases to below the static friction coefficient μ3, slippage occurs between the paper feed roller FR1 and the paper Pa1. Furthermore, when slippage occurs between the paper feed roller FR1 and the paper Pa1, the surface of the paper feed roller FR1 is worn down, reducing the difference between the uneven surface formed by the textured surface, and thus decreasing the dynamic friction coefficient μ1.

[0058] The slippage between the paper feed roller FR1 and the paper Pa1 can be detected by the first motor control unit MC1 by the change in the current flowing to the first motor M1. When slippage occurs between the paper feed roller FR1 and the paper Pa1, the torque required to rotate the paper feed roller FR1 decreases, so the current value decreases through feedback control.

[0059] The pickup roller PR1 has a plurality of protrusions arranged at predetermined intervals in the circumferential direction on its outer surface. The torque for transporting the paper differs depending on whether or not one of the multiple protrusions of the pickup roller PR1 is in contact with the paper. As a result, the current flowing from the first motor control unit MC1 to the first motor M1 fluctuates periodically and appears as a torque current ripple. The period of the torque current ripple is determined by the spacing of the multiple protrusions formed on the outer surface of the pickup roller PR1 and the rotational speed of the pickup roller PR1.

[0060] As explained in Figure 5, the force that transports the paper is mainly generated by the rotation of the paper feed roller FR1. Therefore, the torque distributed to the paper feed roller FR1 is greater than the torque distributed to the pickup roller PR1 when the first motor M1, which is the drive source, is driven by. For this reason, the torque current ripple caused by the period based on the spacing between the multiple protrusions of the pickup roller PR1 does not appear or has a small amplitude in the current flowing to the first motor M1 as controlled by the first motor control unit MC1. On the other hand, when slippage occurs between the paper feed roller FR1 and the paper Pa1, the paper transport force by the paper feed roller FR1 decreases, and the pickup roller PR1 mainly transports the paper instead of the paper feed roller FR1. For this reason, a periodically fluctuating torque current ripple appears in the current flowing to the first motor M1 as controlled by the first motor control unit MC1.

[0061] Figure 6 shows an example of torque current ripple. In Figure 6, the horizontal axis represents the travel distance of the paper feed roller FR1, and the vertical axis represents the current flowing from the first motor control unit MC1 to the first motor M1. The travel distance of the paper feed roller FR1 is the cumulative distance the paper feed roller FR1 has transported. Referring to Figure 6, when the travel distance is less than or equal to the durability threshold LL1, the paper feed roller FR1 has a sufficiently uneven surface. When the travel distance is less than or equal to L1, the amplitude of the torque current ripple is less than or equal to the cleaning threshold LI11, and no slippage occurs between the paper feed roller FR1 and the paper Pa. The cleaning threshold LI11 is a value that has been determined in advance through experiments, etc., as a value indicating that cleaning of the paper feed roller FR1 is necessary.

[0062] When the travel distance exceeds L1, the amplitude of the torque current ripple gradually increases. The amplitude of the torque current ripple becomes the cleaning threshold LI11. Here, we show the case where the paper feed roller FR1 is cleaned and the paper dust attached to the paper feed roller FR1 is removed when the travel distance reaches L2. After cleaning, the amplitude of the torque current ripple becomes less than or equal to the cleaning threshold LI11. Thereafter, until the travel distance reaches the durability threshold LL set for the paper feed roller FR1, the amplitude of the torque current ripple becomes less than or equal to the cleaning threshold LI11 each time the paper feed roller FR1 is cleaned.

[0063] When the travel distance of the paper feed roller FR1 exceeds the durability threshold LL, the amplitude of the torque current ripple gradually increases. When the travel distance reaches L3, the paper feed roller FR1 is cleaned, and although the amplitude of the torque current ripple decreases, it no longer decreases below the cleaning threshold LI11. Furthermore, as the travel distance of the paper feed roller FR1 increases, the amplitude of the torque current ripple gradually increases. Finally, at a travel distance of L4, the amplitude of the torque current ripple reaches the replacement threshold LI12. The replacement threshold LI12 is a value that has been determined in advance through experiments, etc., as an indicator of the state in which the paper feed roller FR1 needs to be replaced.

[0064] Figure 7 is a block diagram showing an example of the functions of the CPU in the printer. The functions shown in Figure 7 are functions realized by the CPU 111 of the printer 100 when the CPU 111 executes a component state detection program stored in the ROM 113, HDD 115, or CD-ROM 118. Referring to Figure 7, the CPU 111 of the printer 100 includes a load detection unit 71, a drive control unit 73, a history generation unit 75, a state detection unit 77, a reset unit 79, and a notification unit 81.

[0065] The drive control unit 73 controls the first motor control unit MC1, the second motor control unit MC2, and the third motor control unit MC3. Specifically, the drive control unit 73 controls the first motor control unit MC1 to drive the first motor M1 during the first period to rotate the paper feed roller FR1 and the pickup roller PR1, and drives the second motor M2 during the second period to rotate the paper feed roller FR2. Each time the first motor M1 rotates the paper feed roller FR1 and the pickup roller PR1, the drive control unit 73 outputs the period during which the first motor M1 rotates the paper feed roller FR1 and the pickup roller PR1 as the first period to the history generation unit 75. Each time the first motor M1 rotates the paper feed roller FR2, the drive control unit 73 outputs the period during which the first motor M1 rotates the paper feed roller FR2 as the second period to the history generation unit 75.

[0066] The drive control unit 73 controls the second motor control unit MC2 to drive the second motor M2 during the third period to rotate the transport roller 37. Each time the second motor M2 rotates the transport roller 37, the drive control unit 73 outputs the period during which the second motor M2 rotates the transport roller 37 as the third period to the history generation unit 75. The drive control unit 73 controls the third motor control unit MC3 to drive the third motor M3 during the fourth period to rotate the timing roller 31. Each time the third motor M3 rotates the timing roller 31, the drive control unit 73 outputs the period during which the third motor M3 rotates the timing roller 31 as the fourth period to the history generation unit 75.

[0067] The history generation unit 75 receives the first to fourth periods as input from the drive control unit 73. The history generation unit 75 generates history information showing the rotation history of each of the paper feed rollers FR1, FR2, 37, and 31. Specifically, the history generation unit 75 generates the first history information of the paper feed roller FR1 by accumulating the first period input from the drive control unit 73 and outputs it to the state detection unit 77. The first history information may be stored in the HDD 115. The history generation unit 75 may also store the date and time when the first period was input from the drive control unit 73 and the first period itself in the HDD 115 as history information for the paper feed roller FR1.

[0068] The history generation unit 75 generates a value by accumulating the second period input from the drive control unit 73 as the second history information of the paper feed roller FR2 and outputs it to the state detection unit 77. The second history information may be stored in the HDD 115. The history generation unit 75 may also store the date and time when the second period was input from the drive control unit 73 and the second period itself in the HDD 115 as the history information of the paper feed roller FR2.

[0069] Similarly, the history generation unit 75 generates a value by accumulating the third period input from the drive control unit 73 as the third history information of the transport roller 37 and outputs it to the state detection unit 77. The third history information may be stored in the HDD 115. The history generation unit 75 may also store the date and time when the third period was input from the drive control unit 73 and the third period itself in the HDD 115 as the history information of the transport roller 37.

[0070] The history generation unit 75 generates the fourth history information of the timing roller 31 by accumulating the value of the fourth period input from the drive control unit 73 and outputs it to the state detection unit 77. The fourth history information may be stored in the HDD 115. The history generation unit 75 may also store the date and time when the fourth period was input from the drive control unit 73 and the fourth period itself in the HDD 115 as history information of the timing roller 31.

[0071] In this embodiment, the first to fourth history information is the cumulative rotation time of the paper feed rollers FR1 and FR2, the transport roller 37, and the timing roller 31, respectively. However, it may also be the transport distance over which the paper was transported. The transport distance is the value obtained by multiplying the rotation time by the peripheral speed calculated from the rotation speed.

[0072] The load detection unit 71 detects the load of the first motor M1, the second motor M2, and the third motor M3. The load detection unit 71 obtains the current values ​​of the current flowing through the first motor M1, the second motor M2, and the third motor M3 from the first motor control unit MC1, the second motor control unit MC2, and the third motor control unit MC3, respectively, and detects the load of the first motor M1, the second motor M2, and the third motor M3 based on the current values.

[0073] The load detection unit 71 acquires the current value supplied to the first motor M1 from the first motor control unit MC1 and detects the load of the first motor M1 based on the current value. The first motor M1 may transmit driving force to the paper feed roller FR1 or to the paper feed roller FR2. The load detection unit 71 detects the load of the first motor M1 as the first load based on the current value acquired from the first motor control unit MC1 while the first motor M1 is transmitting driving force to the paper feed roller FR1. As described above, the current value acquired from the first motor control unit MC1 while the first motor M1 is transmitting driving force to the paper feed roller FR1 includes torque current ripple. The load detection unit 71 detects the amplitude of this torque current ripple as the first load. The first load indicates the fluctuation of the load on the paper feed roller FR1.

[0074] Furthermore, the load detection unit 71 detects the load of the first motor M1 as the second load based on the current value obtained from the first motor control unit MC1 while the first motor M1 is transmitting driving force to the paper feed roller FR2. When paper dust adheres to the outer surface of the paper feed roller FR2, the static friction coefficient decreases. When the paper feed roller FR2 is free-spinning, the load on the paper feed roller FR2 decreases. For this reason, the current value when the paper feed roller FR2 is not free-spinning is greater than the current value when it is free-spinning. The load detection unit 71 detects the fluctuation range of the current value obtained from the first motor control unit MC1 while the first motor M1 is transmitting driving force to the paper feed roller FR2 as the second load. The second load indicates the load on the paper feed roller FR2.

[0075] The load detection unit 71 acquires the current value supplied to the second motor M2 from the second motor control unit MC2 and detects the load of the second motor M2 based on the current value. Similar to the paper feed roller FR2, the static friction coefficient of the transport roller 37 decreases when paper dust adheres to its outer surface. The load detection unit 71 detects the fluctuation range of the current value acquired from the second motor control unit MC2 while the second motor M2 transmits driving force to the transport roller 37 as a third load. The third load indicates the load on the transport roller 37.

[0076] The load detection unit 71 acquires the current value supplied to the third motor M3 from the third motor control unit MC3 and detects the load of the third motor M3 based on the current value. Similar to the paper feed roller FR2, the static friction coefficient of the timing roller 31 decreases when paper dust adheres to its outer surface. The load detection unit 71 detects the fluctuation range of the current value acquired from the third motor control unit MC3 while the third motor M3 transmits driving force to the timing roller 31 as the fourth load. The fourth load indicates the load of the timing roller 31.

[0077] The state detection unit 77 receives the first load of the paper feed roller FR1 from the load detection unit 71 and the first history information of the paper feed roller FR1 from the history generation unit 75. Based on the first load and the first history information, the state detection unit 77 detects the state of the paper feed roller FR1. The paper feed roller FR1 has a predetermined durability threshold D1. The durability threshold D1 is a value determined by experiments or other means as the period during which the paper feed roller FR1 can be used in a functional state.

[0078] If the first history information of the paper feed roller FR1 is less than the durability threshold D1, there is a high probability that the paper feed roller FR1 will recover to a usable state if the user cleans and removes the paper dust, even if paper dust adheres to it and the static friction coefficient decreases. On the other hand, if the first history information of the paper feed roller FR1 is greater than or equal to the durability threshold D1, the height difference of the uneven parts formed by the textured surface on the outer circumference of the paper feed roller FR1 has decreased. Therefore, even after the user cleans and removes the paper dust, slippage may occur in the paper feed roller FR1 if paper dust adheres to it and the static friction coefficient decreases. This slippage is detected by the first load, and the greater the amount of slippage, the smaller the first load becomes.

[0079] The status detection unit 77 determines whether cleaning or replacement of the paper feed roller FR1 is necessary based on the first load. Specifically, the status detection unit 77 determines that cleaning of the paper feed roller FR1 is necessary if the first load is greater than or equal to the cleaning threshold LI11, and determines that replacement of the paper feed roller FR1 is necessary if the first load is greater than or equal to the replacement threshold LI12, which is greater than the cleaning threshold LI11. If the status detection unit 77 determines that cleaning or replacement of the paper feed roller FR1 is necessary, it outputs a notification instruction to the notification unit 81. The notification instruction includes roller identification information to identify the paper feed roller FR1 and information indicating whether cleaning or replacement is necessary. Therefore, the user can be notified of the need to clean or replace the paper feed roller FR1 at an appropriate time.

[0080] Furthermore, the state detection unit 77 determines whether the paper feed roller FR1 has been cleaned or replaced based on the first load acquired at a first time and the first load acquired at a second time. Specifically, the state detection unit 77 determines that the paper feed roller FR1 has been replaced if the first history information of the paper feed roller FR1 is greater than or equal to the durability threshold D1, the first load acquired at a first time is greater than or equal to the first state threshold C11, and the first load acquired at a second time is less than or equal to the second state threshold C12. The second state threshold C12 is smaller than the first state threshold C11. If the state detection unit 77 determines that the paper feed roller FR1 has been replaced, it outputs a reset instruction to the reset unit 79. The reset instruction includes roller identification information for identifying the paper feed roller FR1.

[0081] If the status detection unit 77 determines that the paper feed roller FR1 has been replaced, it outputs a replacement notification instruction to the notification unit 81. The replacement notification instruction includes roller identification information for identifying the paper feed roller FR1.

[0082] Furthermore, the state detection unit 77 determines that the paper feed roller FR1 has been cleaned if the first history information of the paper feed roller FR1 is less than or equal to the durability threshold D1, the first load acquired at the first time is greater than or equal to the first state threshold C11, and the first load acquired at the second time is less than or equal to the third state threshold C13 and greater than the second state threshold C12. The third state threshold C13 is less than the first state threshold C11 and greater than the second state threshold C12. Note that the third state threshold C13 may be the same as the second state threshold C12.

[0083] The state detection unit 77 detects the state of the paper feed roller FR2, the transport roller 37, and the timing roller 31, respectively. The method by which the state detection unit 77 detects the state of the paper feed roller FR2 is the same as the method by which the state detection unit 77 detects the state of the transport roller 37 and the timing roller 31, respectively. Therefore, here we will explain the method by which the state detection unit 77 detects the state of the paper feed roller FR2 as an example, and will not repeat the explanation of how the state detection unit 77 detects the state of the transport roller 37 and the timing roller 31. However, the difference is that the first load is the fluctuation range of the current value flowing through the first motor M1, while the second load is the current value flowing through the second motor M2.

[0084] Furthermore, because the materials and shapes of the paper feed rollers FR1, FR2, transport roller 37, and timing roller 31 differ, multiple thresholds are also defined for each of them. Here, we will explain using the example where the durability threshold D2, cleaning threshold LI21, replacement threshold LI22, first state threshold C21, second state threshold C22, and third state threshold C23 are predetermined for the paper feed roller FR2.

[0085] The state detection unit 77 receives the second load of the paper feed roller FR2 from the load detection unit 71 and the second history information of the paper feed roller FR2 from the history generation unit 75. Based on the second load and the second history information, the state detection unit 77 detects the state of the paper feed roller FR1. The paper feed roller FR2 has a predetermined durability threshold D2. The durability threshold D2 is a value determined by experiments or other means as the period during which the paper feed roller FR2 can be used in a functional state.

[0086] If the second history information of the paper feed roller FR2 is less than the durability threshold D2, the paper feed roller FR2 is highly likely to recover to a usable state if the user cleans and removes the paper dust, even if paper dust adheres to it and the static friction coefficient decreases. On the other hand, if the second history information of the paper feed roller FR2 is greater than or equal to the durability threshold D2, the height difference of the uneven parts formed by the textured surface on the outer circumferential surface of the paper feed roller FR2 has decreased. Therefore, even after the user cleans and removes the paper dust, slippage may occur in the paper feed roller FR2 if paper dust adheres to it and the static friction coefficient decreases. This slippage is detected by the second load, and the greater the amount of slippage, the smaller the first load becomes.

[0087] The status detection unit 77 determines whether cleaning or replacement of the paper feed roller FR2 is necessary based on the second load. Specifically, the status detection unit 77 determines that cleaning of the paper feed roller FR2 is necessary if the second load is greater than or equal to the cleaning threshold LI21, and determines that replacement of the paper feed roller FR2 is necessary if the second load is greater than or equal to the replacement threshold LI22, which is greater than the cleaning threshold LI21. If the status detection unit 77 determines that cleaning or replacement of the paper feed roller FR2 is necessary, it outputs a notification instruction to the notification unit 81. The notification instruction includes roller identification information for identifying the paper feed roller FR2 and information indicating whether cleaning or replacement is necessary.

[0088] Furthermore, the state detection unit 77 determines whether the paper feed roller FR2 has been cleaned or replaced based on the second load acquired at the first time and the second load acquired at the second time. Specifically, the state detection unit 77 determines that the paper feed roller FR2 has been replaced if the second history information of the paper feed roller FR2 is greater than or equal to the durability threshold D2, the second load acquired at the first time is greater than or equal to the first state threshold C21, and the second load acquired at the second time is less than or equal to the second state threshold C22. The second state threshold C22 is smaller than the first state threshold C21. If the state detection unit 77 determines that the paper feed roller FR2 has been replaced, it outputs a reset instruction to the reset unit 79. The reset instruction includes roller identification information for identifying the paper feed roller FR2.

[0089] Furthermore, the state detection unit 77 determines that the paper feed roller FR2 has been cleaned if the second history information of the paper feed roller FR2 is greater than or equal to the durability threshold D2, the second load acquired at the first time is greater than or equal to the first state threshold C21, and the second load acquired at the second time is less than or equal to the third state threshold C23 and greater than the second state threshold C22. The third state threshold C23 is less than the first state threshold C21 and greater than the second state threshold C22. Note that the third state threshold C23 may be the same as the second state threshold C22.

[0090] The reset unit 79 resets the history information corresponding to the roller identification information included in the reset instruction when a reset instruction is input from the state detection unit 77. Specifically, the reset unit 79 resets the history information of the roller identified by the roller identification information included in the reset instruction from the history information generated by the history generation unit 75. For example, the reset unit 79 updates the history information to zero. Since the reset instruction is input when a roller is replaced, the history information generated by the history generation unit 75 shows the history of use since the roller was replaced.

[0091] The notification unit 81 receives a notification instruction or a replacement notification instruction from the status detection unit 77. The notification instruction includes roller identification information and information indicating whether to clean or replace the roller. Depending on the notification instruction received, the notification unit 81 instructs the user to clean or replace the roller. For example, the notification unit 81 displays a message on the display unit 161 prompting the user to clean or replace the roller. Also, depending on the status detection unit 77 that has entered a replacement notification instruction, the notification unit 81 displays a message prompting the user to prepare for replacing the next roller. The user can then take action, such as purchasing, to prepare a new roller for the next replacement. This notification is preferably sent via email or similar means.

[0092] Figure 8 is a flowchart illustrating an example of the component state detection process. The component state detection process is a function implemented by the CPU 111 of the printer 100, which executes a component state detection program stored in the ROM 113, HDD 115, or CD-ROM 118. The components targeted by the component state detection process are the paper feed roller FR1, paper feed roller FR2, transport roller 37, and timing roller 31. The process for detecting the state of each of the paper feed rollers FR1, FR2, transport roller 37, and timing roller 31 differs in the detected load and various thresholds, but the processing flow is the same. Here, we will explain using the detection of the state of the paper feed roller FR1 as an example.

[0093] Referring to Figure 8, the CPU 111 of the printer 100 determines whether or not the power has been turned on (step S01). It remains in a standby state until the power switch is turned ON (NO in step S01), and when the power switch is switched ON (YES in step S01), the process proceeds to step S02.

[0094] In step S02, it is determined whether the printer has returned from power-saving mode. The printer 100 switches its operating mode to either normal mode or power-saving mode, which consumes less power than normal mode. For example, if the printer 100 has been inactive for a predetermined period of time while in normal mode, or if a predetermined period of time has elapsed since the last user operation was received, it will automatically switch to power-saving mode. While in power-saving mode, the printer returns from power-saving mode to normal mode when it receives user operation or when it receives a print job from an external source. If the printer returns from power-saving mode to normal mode, the process proceeds to step S04; otherwise, the process proceeds to step S03.

[0095] In step S03, it is determined whether or not door 150A has been opened or closed. The sensor used to detect the opening or closing of door 150A is, for example, a photoelectric sensor. If it is detected that door 150A has been opened or closed, the process proceeds to step S04; otherwise, the process returns to step S02.

[0096] Steps S04 and beyond are executed after one of the following: when the printer 100 is powered on, when it returns from power-saving mode to normal mode, or when the opening or closing of door 150A is detected. When the paper feed roller FR1 is replaced, the power is off, power-saving mode is active, or door 150A is open. Therefore, it is possible to determine that the paper feed roller FR1 has been replaced immediately after it has been replaced.

[0097] In step S04, history information is acquired, and the process proceeds to step S05. The history information stored in HDD115 is read out. The history information is generated for the paper feed roller FR1 in step S11, which will be described later, and stored in HDD115.

[0098] In step S05, image formation begins, and the process proceeds to step S06. Image formation begins when the user instructs the operation unit 163 to start image formation, or when a print job containing a command to form an image of image data is received from an external source.

[0099] In step S06, a load detection process is performed, and the process proceeds to step S07. The details of the load detection process will be described later, but it is a process that detects the load on the first motor M1 while the first motor M1 is driving the paper feed roller FR1.

[0100] In step S07, the detected load is stored, and the process proceeds to step S08. The load of the first motor M1 that drives the paper feed roller FR1 is stored in the HDD 115 in association with the date and time the load was detected.

[0101] In step S08, a determination process is performed, and the process proceeds to step S09. The details of the determination process will be described later, but it is a process to determine whether or not the paper feed roller FR1 has been replaced. In step S09, the process branches according to the result of the determination process. If it is determined that the paper feed roller FR1 has been replaced, the process proceeds to step S10; otherwise, the process proceeds to step S12. In step S10, the history information is reset, and the process proceeds to step S11. History information is generated showing a value of "0" for the amount of travel corresponding to the paper feed roller FR1. Specifically, history information is generated that includes the amount of travel set to a value of "0", the current date and time, and roller identification information to identify the paper feed roller FR1. In step S11, the user is notified that the transport roller has been replaced, and the process proceeds to step S13. Specifically, a message prompting the user to order a transport roller is sent. For example, the message may be displayed on the display unit 161, or an email may be sent to the email address assigned to the user.

[0102] In step S12, history information is generated, and the process proceeds to step S13. The travel distance is calculated as the distance the paper has been transported by the rotation of the paper feed roller FR1, and history information is generated that includes the travel distance, the current date and time, and roller identification information to identify the paper feed roller FR1.

[0103] In step S13, the history information is updated, and the process proceeds to step S14. If the process proceeds from step S11, the history information reset in step S08 is stored in HDD 115. If the process proceeds from step S12, the history information generated in step S10 is stored in HDD 115.

[0104] In step S14, it is determined whether the power has been cut off or not. If the power switch has been turned OFF by the user, the process ends; otherwise, the process returns to step S02.

[0105] Figure 9 is a flowchart showing an example of the load detection process flow. The load detection process is performed in step S06 of the component state detection process. Referring to Figure 9, the CPU 111 obtains the current value for a predetermined period from the first motor control unit MC1 (step S21) and proceeds to step S22. While the first motor M1 drives the paper feed roller FR1, the current value of the current flowing through the first motor M1 for a predetermined period is obtained.

[0106] In step S22, the torque current ripple is extracted from the current value over a predetermined period, and the process proceeds to step S23. The current value at a predetermined frequency is extracted as the torque current ripple from the current value over the predetermined period. The predetermined frequency is a frequency predetermined as the frequency of the torque current value.

[0107] In step S23, the amplitude of the torque current ripple is acquired, and the process proceeds to step S24. In step S24, the amplitude of the torque current ripple is set as the load, and the process proceeds to step S25. In step S25, the load is stored, and the process returns to the component state detection process. The load is stored in HDD115 in association with the paper feed roller FR1.

[0108] Figure 10 is a flowchart showing an example of the discrimination process flow. The discrimination process is performed in step S08 of the component state detection process. Prior to the execution of the discrimination process, history information corresponding to the paper feed roller FR1 is acquired, and the load corresponding to the paper feed roller FR1 is detected.

[0109] Referring to Figure 10, the CPU 111 of the printer 100 retrieves the previously detected load (step S31) and proceeds to step S32. The previously detected load, which is stored in the HDD 115 in association with the paper feed roller FR1, is read out.

[0110] In step S32, it is determined whether the previously detected load is greater than or equal to the first state threshold C11. If the previously detected load is greater than or equal to the first state threshold C11, the process proceeds to step S33; otherwise, the process returns to the component state detection process.

[0111] In step S33, it is determined whether the travel distance of the paper feed roller FR1 is equal to or greater than the durability threshold LL. If the travel distance of the paper feed roller FR1 is equal to or greater than the durability threshold LL, the process proceeds to step S34; otherwise, the process proceeds to step S38.

[0112] In step S34, it is determined whether the load on the paper feed roller FR1 detected is less than or equal to the second state threshold C12. If the load on the paper feed roller FR1 detected is less than or equal to the second state threshold C12, the process proceeds to step S35; otherwise, the process proceeds to step S36. In step S35, it is determined that the paper feed roller FR1 has been replaced with a new one, and the process returns to the component status detection process.

[0113] In step S36, it is determined whether the load on the paper feed roller FR1 detected this time is below the third state threshold C13. If the load on the paper feed roller FR1 detected this time is below the third state threshold C13, the process proceeds to step S37; otherwise, the process returns to the component state detection process. In step S37, it is determined that the paper feed roller FR1 has been cleaned, and the process returns to the component state detection process. Even if the amount of travel of the paper feed roller FR1 is above the durability threshold LL, cleaning is determined if the load on the paper feed roller FR1 is below the third state threshold C13. If the load on the paper feed roller FR1 is below the third state threshold C13, there is relatively little slippage between the paper feed roller FR1 and the paper, and it is possible to transport the paper properly. For this reason, the paper feed roller FR1 can continue to be used even if the amount of travel exceeds the durability threshold LL.

[0114] In step S38, it is determined whether the load on the paper feed roller FR1 detected is less than or equal to the second state threshold C12. If the load on the paper feed roller FR1 detected is less than or equal to the second state threshold C12, the process proceeds to step S39; otherwise, the process returns to the component state detection process. In step S39, it is determined that the paper feed roller FR1 has been cleaned, and the process returns to the component state detection process.

[0115] <Examples> Figure 11 shows an example of experimental data. In Figure 11, the horizontal axis shows the paper transport time, and the vertical axis shows the amplitude of the torque current ripple. The transport time is defined as the time from when the transport of paper stored in the paper feed cassette 35 begins until the leading edge of the paper is detected by the paper detection sensor SE1. The black dots in the figure indicate the paper transport time and the amplitude of the torque current ripple measured when the paper feed roller FR1 has just been replaced.

[0116] The white dots in the figure represent the paper transport time and torque current ripple amplitude measured when 350K sheets of paper are transported, exceeding the durability threshold LL of the paper feed roller FR1's travel distance. The solid line in the figure is a straight line obtained by regression analysis of multiple white dots. The dotted line in the figure is a straight line obtained by regression analysis of multiple black dots. In addition, the first state threshold C11, second state threshold C12, and third state threshold C13 are shown for the current ripple amplitude.

[0117] The white dots indicate states where the amplitude of the torque current ripple never falls below the second state threshold C12. Therefore, in the paper feed roller FR1, which has reached its replacement time when the amount of travel exceeds the durability threshold LL, the amplitude of the torque current ripple does not fall below the second state threshold C12.

[0118] <Other Embodiments> (1) In the above-described embodiment, the load on the paper feed roller FR1 is the amplitude of the torque current ripple. The load on the other paper feed roller FR2 is the current value flowing through the first motor M1 that drives the paper feed roller FR2. The load on the transport roller 37 is the current value flowing through the second motor M2 that drives the transport roller 37. The load on the timing roller 31 is the current value flowing through the third motor M3 that drives the timing roller 31.

[0119] (2) Although the cleaning threshold LI11 is set to a fixed value, it may be varied according to the amount of travel of the paper feed roller FR1. As the amount of travel of the paper feed roller FR1 increases, the surface wears down, which may cause slippage even if no paper dust is attached. Therefore, in order to prevent the system from determining that cleaning is necessary even when no paper dust is attached to the paper feed roller FR1, the cleaning threshold LI11 is changed to a larger value as the amount of travel increases. This makes it possible to notify the user to clean the paper feed roller FR1 at the appropriate time when paper dust has accumulated on it.

[0120] (3) In the above-described embodiment, the state of the paper feed roller FR1, paper feed roller FR2, transport roller 37, and timing roller 31 was determined, but the state of other members may be determined as long as they rotate around the rotation axis. For example, the state of the fixing belt 57 and intermediate transfer belt 30 of the fixing device 50 may be detected.

[0121] Figure 12 is a cross-sectional view of the fixing device. In Figure 12, the fixing device 50 is shown as a cross-section obtained by cutting the device with the rotation axis 59A of the pressure roller 59 as the normal. Referring to Figure 12, the fixing device 50 includes a heating unit 51 and a pressure roller 59. The heating unit 51 is provided opposite the pressure roller 59 and forms a nip portion N between it and the pressure roller 59. The nip portion N is the part where the heating unit 51 and the pressure roller 59 come into contact. The pressure roller 59 is pressed toward the heating unit 51 with a predetermined pressing force.

[0122] A sheet of paper Pa bearing a toner image To on its surface is transported from below to above the fixing device 50, and the paper Pa passes through the nip section N. While the paper Pa passes through the nip section N, it is heated and pressurized by the pressure roller 59 and the heating section 51, and the toner image To is fixed to the paper Pa.

[0123] The pressure roller 59 consists of a core, an intermediate layer, and a surface layer. In this embodiment, the outer diameter of the pressure roller 59 is 30 mm. The core is made of aluminum or iron, and its thickness is 2 to 3 mm. The intermediate layer is an elastic layer and is formed from a heat-resistant and elastic material such as silicone rubber or silicone sponge. The intermediate layer is preferably about 2 to 5 mm thick. The surface layer is formed from a release material such as a fluorine tube, and the thickness of the surface release layer is preferably about 20 to 80 μm.

[0124] The heating section 51 includes a heating roller 53, a pressurizing section 55, an endless fixing belt 57, and a thermistor 67. The fixing belt 57 is an endless, flexible belt. The fixing belt 57 is suspended by the heating roller 53 and the pressurizing section 55 so as not to slacken. The fixing belt 57 is composed of a base layer and an elastic layer. The base layer is made of a polyimide film with an inner diameter of 40 mm, a width of 340 mm, and a thickness of 70 μm. The elastic layer is made of silicone rubber and preferably has a thickness of about 100 to 150 μm. The surface layer is covered with a release layer made of a fluorine coating with a thickness of about 30 μm.

[0125] The heating roller 53 rotates in accordance with the rotation of the fixing belt 57. Alternatively, the heating roller 53 may be kept stationary, allowing the fixing belt 57 to slide along the surface of the heating roller 53.

[0126] The pressurizing section 55 includes a pressing member 63 and a grease application section 65. The pressing member 63 is made of a heat-resistant resin material and has a shape that has a length at least equal to the maximum paper width to be fixed. The pressing member 63 is fixed to the main frame. The pressing member 63 has a shape in which the portion corresponding to the nip section N approximates the curvature of the pressurizing roller 59. Therefore, the amount of elastic deformation of the pressurizing roller 59 can be reduced while maximizing the area of ​​the nip section N. Because the area of ​​the nip section N can be increased, the time for pressurizing and heating the paper can be increased. Also, because the outer diameter of the pressurizing roller 59 can be reduced to a predetermined value or less, the fixing device 50 can be miniaturized. Also, because the amount of elastic deformation of the pressurizing roller 59 can be reduced, the pressing force applied to the pressurizing roller 59 can be reduced. Therefore, because the strength of the pressurizing roller 59 can be reduced to a predetermined value or less, the wall thickness of the pressurizing roller 59 can be reduced, and the heat capacity can be reduced. Furthermore, because the heat capacity of the pressurizing roller 59 can be reduced, power consumption is reduced.

[0127] A sliding sheet is fixed to the nip portion N side of the pressing member 63 to enhance the sliding properties of the surface of the pressing member 63. The sliding sheet is made of heat-resistant glass cloth coated with fluororesin, and possesses heat resistance, wear resistance, and sliding properties. The fixing belt 57 is in contact with the sliding sheet. Therefore, the degree to which the fixing belt 57 is worn down by friction can be minimized.

[0128] The grease application section 65 stores grease, which is a lubricant, and applies grease to the fixing belt 57 at the part that comes into contact with the fixing belt 57. As the fixing belt 57 passes through the grease application section 65, grease is applied to the inner surface of the fixing belt 57 by friction between the fixing belt 57 and the grease application section 65. As a result, the frictional resistance that the fixing belt 57 receives from the pressing member 63 is reduced, and the load on the fixing belt 57 to rotate around the heating roller 53 and the pressurizing section 55 is reduced.

[0129] The heating roller 53 is a hollow cylindrical component with a heat source 61 built inside. The inner diameter of the heating roller 53 is set to a size that does not come into contact with the heat source 61. The heating roller 53 is made of stainless steel. Because the heating roller 53 is made of stainless steel, strength is ensured and it is easy to process. In this case, the thickness of the heating roller 53 can be around 0.1 mm to 0.2 mm. The heating roller 53 may also be made of aluminum. In this case, it is preferable that the thickness of the heating roller 53 be 0.25 mm or more in order to ensure strength against bending and local deformation. The heating roller 53 may also be made of an iron-based metal such as STKM (carbon steel pipe for machine structures).

[0130] The heat source 61 is, for example, a halogen heater. In this embodiment, two halogen heaters with different emission lengths are used as the heat source 61. Note that the heat source 61 is not limited to halogen heaters, and a resistance heating element or IH (Induction Heating) may also be used.

[0131] When the heat source 61 generates heat, the heating roller 53 is heated, and the temperature of the heating roller 53 rises. The thermistor 67 detects the temperature of the heating roller 53. According to the temperature detected by the thermistor 67, the heat source 61 is controlled to turn on or off, so that the heating roller 53 reaches a predetermined temperature. By making the heating roller 53 thinner, the heat capacity of the heating roller 53 is reduced. Therefore, the rate at which the heating roller 53 heats up becomes faster, so the warm-up time until the heating roller 53 reaches a predetermined temperature can be shortened. In addition, the power consumption of the heat source 61 can be reduced.

[0132] The fixing belt 57 is heated to a predetermined temperature by the heat transferred from the heating roller 53 while in contact with the heating roller 53.

[0133] The pressure roller 59 is rotated by the drive motor 59B. As the pressure roller 59 rotates, the fixing belt 57 rotates in response. The fixing belt 57 is heated by the heating roller 53 while it is rotating. After the fixing belt 57 is heated to a predetermined temperature, the paper Pa carrying the toner image To is controlled to enter the nip section N. As the paper Pa passes through the nip section N, the toner image To is fixed to the paper Pa by heat and pressure.

[0134] If paper dust adheres to the surface of the fixing belt 57, the fixing belt may slip between itself and the paper. When the fixing belt 57 slips between itself and the paper, the load on the drive motor 59B that drives the pressure roller 59 decreases, and the current value flowing to the drive motor 59B decreases. By comparing the current value flowing to the drive motor 59B with a threshold value, the condition of the fixing belt 57 can be detected, and it can be detected that the fixing belt 57 has been replaced. In addition, the user can be notified at an appropriate time about cleaning and replacing the fixing belt 57.

[0135] (4) In this embodiment, a printer 100 was described as an example of an image forming apparatus, but the image forming apparatus may also be a copier, a laser beam printer, a facsimile machine, or a multifunction device (Multi Function Peripheral) that combines these.

[0136] Furthermore, in this embodiment, a tandem-type color image forming printer 100 was described as an example of an image forming apparatus, but it is not limited to this, and an image forming apparatus that forms monochrome images may also be used. The configuration and arrangement of the image forming units 20Y, 20M, 20C, 20K, exposure apparatus 21Y, 21M, 21C, 21K, charging rollers 22Y, 22M, 22C, 22K, photoreceptor drums 23Y, 23M, 23C, 23K, developer 24Y, 24M, 24C, 24K, primary transfer rollers 25Y, 25M, 25C, 25K, secondary transfer roller 26, and fixing apparatus 50 are not limited to this embodiment, and other configurations and arrangements may be used.

[0137] As described above, the printer 100 in this embodiment functions as an image forming apparatus and is equipped with a first motor M1 that drives the paper feed roller FR1 and the pickup roller PR1. The CPU 111 detects the load on the first motor M1 and detects the state of the paper feed roller FR1 based on the history of how the paper feed roller FR1 has been driven by the first motor M1 and the amount of change in the load on the first motor M1. Therefore, since the state of the paper feed roller FR1 is detected from the amount of change in the load on the first motor M1 that drives the object after the paper feed roller FR1, whose state changes with use, has been used for a predetermined period of time, the state of the paper feed roller FR1 can be detected while the paper feed roller FR1 is being driven.

[0138] Furthermore, the paper feed roller FR1 feeds the recording medium by rotating around its axis. Since the load received from the first motor M1 can be detected from the paper feed roller FR1 when it is feeding the recording medium, the state of the object can be detected while the recording medium is being fed to the paper feed roller FR1.

[0139] The CPU 111 detects that the paper feed roller FR1 has been replaced if the amount of travel of the paper feed roller FR1 is greater than or equal to the durability threshold LL, the first load detected at the first time step is greater than or equal to the first state threshold C11, and the second load detected at the second time step (after the first time step) is less than or equal to the second state threshold C12, which is less than the first state threshold C11. The load on the paper feed roller FR1 when it has been used until it exceeds the durability threshold LL is different from the load on the paper feed roller FR1 when it is new. If the second state threshold C12 is set to a value less than the minimum load on the paper feed roller FR1 when it has been used until it exceeds the durability threshold LL, it can be determined that the paper feed roller FR1 has been replaced with a new one. Therefore, it can be determined that the paper feed roller FR1 was replaced with a new one between the first and second time steps.

[0140] Furthermore, the CPU 111 detects that the paper feed roller FR1 has been cleaned when the amount of travel by the paper feed roller FR1 is greater than or equal to the durability threshold LL, the first load is greater than or equal to the first state threshold C11, and the second load is less than the first state threshold C11 and greater than the second state threshold C12. Therefore, the load on the paper feed roller FR1, which has been used until it exceeds the durability threshold LL, decreases after cleaning, but it does not become the load of a new roller. For this reason, if the second load is less than the first state threshold C11 and greater than the second state threshold C12, it can be determined that the paper feed roller FR1 was cleaned between the first and second time points.

[0141] Furthermore, the CPU 111 detects that the paper feed roller FR1 has been cleaned when the amount of travel is less than the durability threshold LL, the first load is greater than or equal to the first state threshold C11, and the second load is less than the first state threshold C11. The load on the paper feed roller FR1 before use, when it is used to the point where it exceeds the durability threshold LL, increases with use and may return to the load of a new roller after cleaning. Therefore, it can be determined that the object has been cleaned between the first and second time points.

[0142] Furthermore, the CPU 111 detects the amplitude of the current flowing through the first motor M1, which is controlled by the first motor control unit MC1, as a load. The pickup roller PR1 has a plurality of protrusions on its outer circumference that are spaced at predetermined intervals in the circumferential direction. Therefore, the load received from the paper feed roller FR1 and the pickup roller PR1 fluctuates with a period determined by the spacing of the multiple protrusions formed on the outer circumference of the pickup roller PR1. Since this fluctuation range is detected as the load, it is possible to accurately detect when the paper feed roller FR1 is worn out.

[0143] Furthermore, the CPU 111 determines the state of the paper feed roller FR1 at at least one of the following times: when the main unit power is switched ON, when the operating mode switches from power-saving mode to normal mode, and when the door of the main unit casing is opened or closed. This allows the state of the paper feed roller FR1 to be detected after a period in which it may have been replaced or cleaned.

[0144] Furthermore, the CPU 111 resets the travel history of the paper feed roller FR1 in response to detecting that the paper feed roller FR1 has been replaced. This allows for accurate detection of when the paper feed roller FR1 has been used up to the durability threshold LL.

[0145] Furthermore, when the CPU 111 detects that the paper feed roller FR1 has been replaced, it generates and outputs information regarding the replenishment of the paper feed roller FR1. This allows the user to prepare for the next time they need to replace the paper feed roller FR1, such as by purchasing a new paper feed roller.

[0146] Furthermore, the CPU 111 detects the load on the paper feed roller FR2 from the magnitude of the current flowing through the first motor M1 that drives the paper feed roller FR2, the load on the transport roller 37 from the magnitude of the current flowing through the second motor M2, and the load on the timing roller 31 from the magnitude of the current flowing through the third motor M3. Therefore, the load on the paper feed roller FR2, the transport roller 37, or the timing roller 31 while they are transporting the recording medium can be easily detected.

[0147] <Summary of Embodiments> (Item 1) A drive source that drives the object, A load detection unit that detects the load received by the drive source, An image forming apparatus comprising a state detection unit that detects the state of an object based on the history of how the object has been driven by the drive source and the amount of change in the load received by the drive source.

[0148] In this scenario, the state of the object is detected based on the history of how the object has been driven by the drive source and the change in the load on the drive source. Therefore, since the state of an object whose state changes with use is detected from the change in the load on the drive source that drives the object after it has been used for a predetermined period, the state of the object can be detected while the object is being driven. As a result, it is possible to provide an image forming apparatus that can detect the state of an object whose state changes with use while the object is being driven.

[0149] (Item 2) The image forming apparatus according to Item 1, wherein the object is a member that transports a recording medium on which an image is formed by rotating around a rotation axis.

[0150] Following this approach, the load received by the object from the drive source when the object is transporting the recording medium can be detected, allowing the object's state to be detected while it is transporting the recording medium.

[0151] (Item 3) The image forming apparatus according to Item 1 or 2, wherein the state detection unit detects that the object has been replaced when the history shows a predetermined durability threshold or higher, and the first load detected at the first time is equal to or greater than the first threshold and the second load detected at the second time, which is after the first time, is less than or equal to a second threshold less than the first threshold.

[0152] According to this scenario, the load on an object used until it exceeds the durability threshold is different from the load on an object in a new condition. If the second threshold is set to a value smaller than the minimum load on an object used until it exceeds the durability threshold, it can be determined that the object has been replaced with a new one. Therefore, it can be determined that the object was replaced with a new one between the first and second time points.

[0153] (Item 4) The image forming apparatus according to Item 3, wherein the state detection unit detects that the object has been cleaned when the history is greater than or equal to the durability threshold, the first load is greater than or equal to the first threshold, and the second load is less than the first threshold and greater than the second threshold.

[0154] In this scenario, the load on an object that has been used to the point of exceeding its durability threshold decreases upon cleaning, but it does not become the same load as when it was new. Therefore, if the second load is less than the first threshold and greater than the second threshold, it can be determined that the object was cleaned between the first and second time points.

[0155] (Item 5) The image forming apparatus according to item 3 or 4, wherein the state detection unit detects that the object has been cleaned when the history is less than the durability threshold, the first load is greater than or equal to the first threshold, and the second load is less than the first threshold.

[0156] In this scenario, the load on an object before it is used beyond its durability threshold increases with use and may return to the load of a new object after cleaning. Therefore, it can be determined that the object was cleaned between the first and second time points.

[0157] (Item 6) The drive source comprises a motor and The motor comprises a current control unit for current control, The image forming apparatus according to any one of items 1 to 5, wherein the load detection unit detects the magnitude of the current flowing through the motor as the load when controlled by the current control unit.

[0158] In this scenario, the current control unit detects the magnitude of the current flowing through the motor as the load. Therefore, the load on the object can be easily detected while the object is transporting the recording medium.

[0159] (Item 7) The paper feed roller as the object, The system includes a pickup roller positioned upstream of the aforementioned paper feed roller and having a plurality of protrusions on its outer surface spaced at predetermined intervals in the circumferential direction, The drive source includes a motor that drives the paper feed roller and the pickup roller, The motor comprises a current control unit for current control, The image forming apparatus according to any one of items 1 to 5, wherein the load detection unit detects the magnitude of the amplitude of the current flowing through the motor as the load, as determined by the current control unit.

[0160] In this configuration, the pickup roller has multiple protrusions on its outer surface that are spaced at predetermined intervals in the circumferential direction, and the drive source drives both the paper feed roller and the pickup roller. Therefore, the load received by the paper feed roller and the pickup roller fluctuates with a period determined by the spacing of the multiple protrusions formed on the outer surface of the pickup roller. Since this fluctuation range is detected as the load, it is possible to accurately detect when the paper feed roller is worn out.

[0161] (Item 8) The image forming apparatus according to any one of items 1 to 7, wherein the history is the time and number of rotations the object rotates around the rotation axis, or the number of recording media conveyed by the object.

[0162] Following this procedure allows for accurate measurement of the object's driving history.

[0163] (Item 9) The image forming apparatus according to any one of Items 1 to 8, wherein the state detection unit determines the state of the object at at least one timing when the main power supply is switched to ON, when the device switches from a power-saving mode which consumes less power than the normal mode to the normal mode, and when the door of the main housing is opened or closed.

[0164] Following this approach, the condition of the object can be detected after a period in which it may have been replaced or cleaned.

[0165] (Item 10) The image forming apparatus according to any one of items 1 to 9, further comprising a reset unit that resets the history in response to the state detection unit detecting that the object has been replaced.

[0166] Following this approach, the history is reset whenever it is detected that the object has been replaced, allowing for accurate detection of when the object has been used beyond its durability threshold.

[0167] (Item 11) The image forming apparatus according to any one of items 1 to 10, further comprising a notification means for generating and outputting information regarding the replenishment of the object in response to the detection by the state detection unit that the object has been replaced.

[0168] In this scenario, when it is detected that an object has been replaced, information regarding the replenishment of that object is generated and output. This allows the user to prepare for the next task of replacing the object.

[0169] (Item 12) A method for detecting the state of a component, which is performed in an image forming apparatus equipped with a drive source for driving an object, A load detection step for detecting the load on the drive source, A member state detection method comprising a state detection step of detecting the state of an object based on the history of how the object has been driven by the drive source and the load received by the drive source.

[0170] Following this approach, it is possible to provide a component state detection method that can detect the state of an object whose state changes due to use, while the object is being driven.

[0171] (Item 13) A method for detecting the state of a component, which is performed in an image forming apparatus equipped with a drive source for driving an object, A load detection step for detecting the load on the drive source, A member state detection program comprising a state detection step for detecting the state of an object based on the history of how the object has been driven by the drive source and the load on the drive source.

[0172] Following this approach, it is possible to provide a component state detection program that can detect the state of an object, whose state changes with use, while the object is being driven.

[0173] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0174] 100 Printer, 111 CPU, 113 ROM, 114 RAM, 115 HDD, 117 External storage device, 118 CD-ROM, 140 Image forming unit, 150 Paper feed unit, 150A Door, 160 Operation panel, 161 Display unit, 163 Operation unit, 165 Touch panel, 167 Hard key unit, C11 First state threshold, C12 Second state threshold, C13 Third state threshold, D1 Durability threshold, LI11 Cleaning threshold, LI12 Replacement threshold, LL Durability threshold, M1 First motor, M2 Second motor, M3 Third motor, MC1 First motor control unit, MC2 Second motor control unit, MC3 Third motor control unit, 30 Intermediate transfer belt, FR1 Paper feed roller, PR1 Pickup roller, 31 Timing roller, 35 Paper feed cassette, 35A Manual feed cassette, 37,38 Transport rollers, 71 Load detection unit, 73 drive control unit, 75 history generation unit, 77 state detection unit, 79 reset unit, 81 notification unit.

Claims

1. A drive source that drives the object, A load detection unit that detects the load received by the drive source, An image forming apparatus comprising: a state detection unit that detects the state of an object based on a first load detected at a first time and a second load detected at a second time after the first time, when the history of the object being driven by the drive source exceeds a predetermined durability threshold.

2. The image forming apparatus according to claim 1, wherein the object is a member that transports a recording medium on which an image is formed by rotating around a rotation axis.

3. The image forming apparatus according to claim 1, wherein the state detection unit detects that the object has been replaced when the history is greater than or equal to a predetermined durability threshold, and the first load is greater than or equal to a first threshold and the second load is less than or equal to a second threshold which is less than the first threshold.

4. The image forming apparatus according to claim 3, wherein the state detection unit detects that the object has been cleaned when the history is greater than or equal to the durability threshold, the first load is greater than or equal to the first threshold, and the second load is less than the first threshold and greater than the second threshold.

5. The image forming apparatus according to claim 3, wherein the state detection unit detects that the object has been cleaned when the history is less than the durability threshold, the first load is greater than or equal to the first threshold, and the second load is less than the first threshold.

6. The aforementioned drive source includes a motor and The motor comprises a current control unit for current control, The image forming apparatus according to any one of claims 1 to 5, wherein the load detection unit detects the magnitude of the current flowing through the motor as the load when controlled by the current control unit.

7. The aforementioned object is the paper feed roller, The system includes a pickup roller positioned upstream of the aforementioned paper feed roller and having a plurality of protrusions on its outer surface spaced at predetermined intervals in the circumferential direction, The drive source includes a motor that drives the paper feed roller and the pickup roller, The motor comprises a current control unit for current control, The image forming apparatus according to any one of claims 1 to 5, wherein the load detection unit detects the magnitude of the amplitude of the current flowing through the motor as the load.

8. The image forming apparatus according to any one of claims 1 to 5, wherein the history is the time and number of rotations the object rotates around the rotation axis, or the number of recording media conveyed by the object.

9. The image forming apparatus according to any one of claims 1 to 5, wherein the state detection unit detects the state of the object at at least one timing when the main power supply is switched ON, when the device switches from a power-saving mode which consumes less power than the normal mode to the normal mode, and when the door of the main housing is opened or closed.

10. The image forming apparatus according to any one of claims 1 to 5, further comprising a reset unit that resets the history in response to the state detection unit detecting that the object has been replaced.

11. The image forming apparatus according to any one of claims 1 to 5, further comprising a notification means for generating and outputting information prompting preparation work for replacing the object next, in response to the detection by the state detection unit that the object has been replaced.

12. A method for detecting the state of a component, performed in an image forming apparatus equipped with a drive source for driving an object, A load detection step for detecting the load on the drive source, A member state detection method, which includes a state detection step of detecting the state of an object based on a first load detected at a first time and a second load detected at a second time after the first time, when the history of the object being driven by the drive source exceeds a predetermined durability threshold.

13. A method for detecting the state of a component, performed in an image forming apparatus equipped with a drive source for driving an object, A load detection step for detecting the load on the drive source, A component state detection program that causes a computer to perform a state detection step of detecting the state of the object based on a first load detected at a first time and a second load detected at a second time after the first time, when the history of the object being driven by the drive source exceeds a predetermined durability threshold.

Images