Sheet feeding status determination method, sheet feeding device, image forming apparatus

Abstract

To determine the deterioration status of the sheet feeding device without requiring the addition of equipment. [Solution] The feeding mechanism 20 performs the feeding process by rotating the feeding rotating body 22 and the delivery rotating body 23, and separates the accompanying sheets from each sheet using the separation member 24. The sheet detection device 25 detects each sheet at the detection position. The timing device 8e measures the elapsed time from the time the feeding process is started until the time each sheet is detected by the sheet detection device 25. The processing device 81 derives a positional deviation amount representing the amount of positional deviation of the target sheet based on the target measurement time and reference feeding time measured by the timing device 8e for the target sheet. The processing device 81 counts the number of times the positional deviation amount exceeds the separation failure judgment value, which is the number of times. The processing device 81 determines the deterioration state of the feeding mechanism 20 based on the number of separation failures.

Description

Technical Field

[0001] The present invention relates to a sheet feeding state determination method, a sheet feeding device, and an image forming device that determine the state of a sheet feeding device based on the time required for sheet feeding.

Background Art

[0002] An image forming apparatus includes a sheet conveying device and a printing device that forms an image on a conveyed sheet. The sheet conveying device includes a sheet feeding device that feeds the uppermost sheet in a stacked sheet to a conveyance path, and a plurality of pairs of conveyance rollers that convey the sheet along the conveyance path.

[0003] The sheet feeding device includes a sheet detection device that detects the sheet fed to the conveyance path. It is known that the image forming apparatus measures the sheet feeding speed based on the detection result of the sheet detection device (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in the sheet feeding device, sheet separation failure may occur due to deterioration of components in contact with the sheet. The separation failure is a phenomenon in which a plurality of sheets are fed to the conveyance path in a stacked state. Therefore, it is desirable to be able to determine the deterioration state of the sheet feeding device without requiring additional equipment.

[0006] An object of the present invention is to provide a sheet feeding state determination method, a sheet feeding device, and an image forming device that can determine the deterioration state of a sheet feeding device without requiring additional equipment. [Means for solving the problem]

[0007] A sheet feeding state determination method according to one aspect of the present invention is a method for determining the state of a sheet feeding device. The sheet feeding device comprises a feeding mechanism, a sheet detection device, and a timing device. The feeding mechanism comprises a feeding rotating body that contacts the upper surface of the uppermost sheet in the stacked sheet, a delivery rotating body arranged at a distance from the feeding rotating body, and a separation member arranged below the delivery rotating body and biased toward the delivery rotating body. By rotating the feeding rotating body and the delivery rotating body, a feeding process is performed to feed each sheet from the stacked sheet to a transport path, and accompanying sheets that are sent out together with each sheet are separated from each sheet by the separation member. The sheet detection device detects each sheet at a detection position downstream in the sheet feeding direction relative to the delivery rotating body and the separation member. The timing device measures the elapsed time from the time when the feeding process for each sheet is started until the time when each sheet is detected by the sheet detection device. The sheet feeding state determination method includes the processing device deriving a positional deviation amount, which represents the amount of deviation of the target sheet's position from the initial reference position at the start of the feeding process for the target sheet, based on the target measurement time measured by the timing device and a preset reference feeding time for the target sheet fed by the feeding process. Furthermore, the sheet feeding state determination method includes the processing device counting the number of separation failures, which is the number of times the positional deviation amount exceeds a separation failure determination value corresponding to the path length from the initial reference position to the separation member. Furthermore, the sheet feeding state determination method includes the processing device determining the deterioration state of the feeding mechanism based on the number of separation failures.

[0008] A sheet feeding device according to another aspect of the present invention comprises the feeding mechanism, the sheet detection device, the timing device, and the processing device for implementing the sheet feeding state determination method.

[0009] A sheet feeding device according to another aspect of the present invention comprises the feeding mechanism, the lift mechanism, the sheet detection device, the timing device, and the processing device for implementing the sheet feeding state determination method.

[0010] An image forming apparatus according to another aspect of the present invention comprises a sheet feeding device and a printing device that forms an image on each sheet fed by the sheet feeding device. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a sheet feeding state determination method, a sheet feeding device, and an image forming apparatus that can determine the deterioration state of a sheet feeding device without requiring the addition of equipment. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a configuration diagram of an image forming apparatus according to an embodiment. [Figure 2] Figure 2 is a block diagram showing the configuration of the control device in the image forming apparatus according to the embodiment. [Figure 3] Figure 3 is a diagram showing the configuration of the sheet feeding device in the image forming apparatus according to the embodiment. [Figure 4] Figure 4 shows the sheet feeding apparatus in the image forming apparatus according to the embodiment before the feeding process is started. [Figure 5] Figure 5 is a flowchart showing an example of the sheet feeding control procedure in an image forming apparatus according to this embodiment. [Figure 6] Figure 6 is a flowchart showing an example of the procedure for determining the feeding state in the image forming apparatus according to the embodiment. [Figure 7] Figure 7 is a flowchart showing an example of the procedure for determining component deterioration in an image forming apparatus according to an embodiment. [Figure 8] Figure 8 shows a first example of the relationship between the target measurement time, target feeding time, and delay time in an image forming apparatus according to an embodiment. [Figure 9]FIG. 9 is a diagram showing a second example of the relationship among the target measurement time, the target feeding time, and the delay time in the image forming apparatus according to the embodiment. [Figure 10] FIG. 10 is a diagram showing a third example of the relationship among the target measurement time, the target feeding time, and the delay time in the image forming apparatus according to the embodiment. [Figure 11] FIG. 11 is a diagram showing a fourth example of the relationship among the target measurement time, the target feeding time, and the delay time in the image forming apparatus according to the embodiment. [Figure 12] FIG. 12 is a diagram showing a fifth example of the relationship among the target measurement time, the target feeding time, and the delay time in the image forming apparatus according to the embodiment. [Figure 13] FIG. 13 is a flowchart showing an example of the procedure of sheet feeding control according to the first modification.

Embodiments of the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following embodiments are merely examples of embodying the present invention and do not limit the technical scope of the present invention.

[0014] [Configuration of Image Forming Apparatus 10] The image forming apparatus 10 according to the embodiment includes a sheet feeding device 2, a sheet conveying device 3, and a printing device 4. Further, the image forming apparatus 10 also includes a control device 8, an operation device 801, a display device 802, and the like.

[0015] Furthermore, the image forming apparatus 10 includes a main housing 1 that houses the sheet feeding device 2, the sheet conveying device 3, and the printing device 4. The main housing 1 includes a lower housing 1a that forms the housing of the sheet feeding device 2. <​​​​ The sheet cassette 200 houses the loading sheet 90 and is retractably mounted in the lower housing 1a. The sheet cassette 200 is an example of a sheet storage unit.

[0018] The pickup roller 22 and the delivery roller 23 are each rotatably supported and spaced apart. The pickup roller 22 contacts the upper surface of the top sheet on the loading sheet 90. The feeding mechanism 20 further includes a feeding motor 230 that rotates the pickup roller 22 and the delivery roller 23 (see Figure 3).

[0019] The feeding mechanism 20 performs the feeding process by rotating the pickup roller 22 and the delivery roller 23. The feeding process involves feeding each of the sheets 9 from the loading sheet 90 to the transport path 30. The transport path 30 is the passage for each of the sheets 9.

[0020] The feed roller 23 and retard roller 24 are located in the area between the sheet cassette 200 and the transport path 30. The retard roller 24 is located below the feed roller 23 and faces the feed roller 23. The retard roller 24 forms a nip between itself and the feed roller 23, sandwiching each sheet 9.

[0021] In the sheet feeding device 2, the sheet feeding direction D1 is the direction from the sheet cassette 200 to the transport path 30 (see Figure 1). The delivery roller 23 is positioned downstream of the pickup roller 22 in the sheet feeding direction D1 (see Figures 1 and 3).

[0022] The pickup roller 22 is an example of a feeding rotating body. The discharge roller 23 is an example of a discharge rotating body.

[0023] The retard roller 24 is rotatably supported. The feeding mechanism 20 further includes a torque limiter 24a connected to the rotation axis of the retard roller 24, and a spring 241 that biases the retard roller 24 toward the feed roller 23 (see Figure 3).

[0024] When the feeding process is performed, a torque DR1 in the forward rotation direction acts on the retard roller 24 from either the rotating feed roller 23 or the sheet 9 moving toward the conveying path 30.

[0025] The torque limiter 24a restricts the rotation of the retard roller 24 in the forward rotation direction DR1 when the torque acting on the retard roller 24 in the forward rotation direction DR1 is less than or equal to the rated torque (see Figure 3).

[0026] The retard roller 24 blocks the accompanying sheets by contacting the leading edge of one or more accompanying sheets that are fed out with each sheet 9 when the feeding process is performed. In this way, the retard roller 24 separates the accompanying sheets from each sheet 9. The accompanying sheets are fed out from the sheet cassette 200 so that they overlap the underside of the top sheet on the stacked sheet 90.

[0027] Furthermore, if the torque acting on the retard roller 24 from either the rotating discharge roller 23 or the sheet 9 moving toward the conveyor path 30 exceeds the rated torque of the torque limiter 24a, the retard roller 24 rotates in the forward rotation direction DR1. This prevents either the discharge roller 23 or the sheet 9 from receiving excessive frictional force from the retard roller 24.

[0028] The retard roller 24 is an example of a separating member that separates the auxiliary sheet from the uppermost sheet of the loading sheet 90. A non-rotating separating pad may be used as the separating member instead of the retard roller 24.

[0029] In the following description, the position of each sheet 9 when its leading edge is aligned with the cassette front wall surface 200a is referred to as the initial reference position P1 (see Figures 1 and 3). The cassette front wall surface 200a is the inner wall surface of the downstream end of the sheet cassette 200 in the sheet feeding direction D1. The position between the delivery roller 23 and the retard roller 24 is referred to as the separation position P2 (see Figures 1 and 3).

[0030] The lift mechanism 21 is located within the sheet cassette 200 and is supported by the sheet cassette 200. The lift mechanism 21 supports the loading sheet 90 so that it can be raised and lowered.

[0031] The lift mechanism 21 is a mechanism for lifting the loading sheet 90 from a separation position to a contact position. The separation position is the position where the upper surface of the top sheet of the loading sheet 90 is separated from the pickup roller 22. The contact position is the position where the upper surface of the top sheet of the loading sheet 90 is in contact with the pickup roller 22.

[0032] The lift mechanism 21 comprises a lift plate 211 and a push-up plate 212. The lift plate 211 is rotatably supported around a pivot axis 211a, which is positioned along the bottom plate of the sheet cassette 200. That is, the lift plate 211 is rotatable up and down around the pivot axis 211a.

[0033] The loading sheet 90 is placed on the lift plate 211. When the lift plate 211 rotates upward, the loading sheet 90 rotates upward, and when the lift plate 211 rotates downward, the loading sheet 90 rotates downward.

[0034] The push-up plate 212 is positioned below the lift plate 211 and is supported so as to be rotatable around a pivot shaft 212a that is positioned along the bottom plate of the sheet cassette 200. In other words, the push-up plate 212 is rotatable up and down around the pivot shaft 212a.

[0035] The push-up plate 212 rotates in a first rotational direction by the driving force of a motor (not shown), thereby pushing the lift plate 211 and the loaded sheet 90 on the lift plate 211 upward. That is, the lift mechanism 21 lifts the loaded sheet 90 on the lift plate 211 from the separated position to the contact position by rotating the push-up plate 212 in the first rotational direction.

[0036] Meanwhile, the push-up plate 212 rotates in the second rotational direction by the driving force of the motor, thereby lowering the lift plate 211 and the loading sheet 90 on the lift plate 211. In other words, the lift mechanism 21 lowers the loading sheet 90 on the lift plate 211 from the contact position to the separation position by rotating the push-up plate 212 in the second rotational direction.

[0037] The feed sheet detection device 25 detects each sheet 9 being fed by the feeding process at a detection position P3 downstream of the feed roller 23 in the sheet feeding direction D1. For example, the feed sheet detection device 25 includes a pivotably supported actuator and a photosensor that detects when the actuator swings. The actuator swings by coming into contact with each sheet 9 passing through the detection position P3.

[0038] The sheet feeding detection device 25 may also be a transmissive or reflective photosensor that detects each sheet 9 passing through the detection position P3.

[0039] The sheet feeding device 2 further includes a mounting detection device 26 located on the lower housing 1a (see Figure 1). The mounting detection device 26 detects whether the sheet cassette 200 is in a mounted state, mounted in the lower housing 1a, or in an unmounted state, pulled out from the lower housing 1a.

[0040] For example, the mounting detection device 26 is a reflective photosensor or microswitch that detects a portion of the sheet cassette 200 in the mounted state.

[0041] When the seat cassette 200 is in the aforementioned mounting state, the lift mechanism 21 can lift the loading sheet 90 to the aforementioned contact position.

[0042] The sheet cassette 200 further comprises an end cursor 213 and a pair of side cursors 214. The end cursor 213 is provided to be movable along the sheet feeding direction D1. The end cursor 213 is positioned along the rear end of the loaded sheet 90 placed on the lift plate 211. This prevents the loaded sheet 90 from shifting upstream of the initial reference position P1 in the sheet feeding direction D1.

[0043] A pair of side cursors 214 are arranged to be interlocked so as to move toward or away from each other along the width direction D2, which is perpendicular to the sheet feeding direction D1.

[0044] The pair of side cursors 214 are positioned along both ends of the loading sheet 90 placed on the lift plate 211 in the width direction D2. This prevents the loading sheet 90 from shifting from a specific position in the width direction D2.

[0045] The sheet conveying device 3 conveys each of the sheets 9 supplied by the sheet feeding device 2 along the conveying path 30. In this embodiment, the sheet conveying device 3 includes a plurality of pairs of conveying rollers 31 and a conveying sheet detection device 32 arranged along the conveying path 30.

[0046] Multiple sets of conveying rollers 31 convey each sheet 9 by rotating individually. Each set of conveying rollers 31 includes a resist roller set 31a and a discharge roller set 31b.

[0047] The resist roller pair 31a is positioned at resist position P4 in the transport path 30. The discharge roller pair 31b is positioned at the end of the transport path 30.

[0048] The resist roller pair 31a pauses each sheet 9 fed by the sheet feeder 2 at the resist position P4, and then sends it to the print position P5 in the transport path 30.

[0049] The transport sheet detection device 32 detects each sheet 9 as it moves towards the resist position P4 after being fed into the transport path 30 by the sheet feeding device 2. The transport sheet detection device 32 has the same configuration as the feeding sheet detection device 25.

[0050] The discharge roller pair 31b discharges each sheet 9 that has passed through print position P5 from the transport path 30 to the discharge tray 101. As will be described later, an image is formed on each sheet 9 at print position P5.

[0051] The printing device 4 forms an image on each of the sheets 9 transported by the sheet transport device 3. That is, the printing device 4 forms an image on each of the sheets 9 supplied by the sheet feeding device 2. The printing device 4 forms an image on each of the sheets 9 at the printing position P5 in the transport path 30.

[0052] In the example shown in Figure 1, the printing device 4 forms an image on each of the sheets 9 using an electrophotographic method. In this case, the printing device 4 includes a light scanning unit 40, one or more image forming units 4x, a transfer device 44, and a fixing device 46.

[0053] In the example shown in Figure 1, the printing apparatus 4 includes multiple image forming units 4x corresponding to multiple development colors. Each image forming unit 4x includes a drum-shaped photoreceptor 41, a charging device 42, a developing device 43, and a drum cleaning device 45. For example, the multiple development colors are cyan, yellow, magenta, and black.

[0054] Furthermore, the transfer apparatus 44 includes an intermediate transfer belt 440, a plurality of primary transfer devices 441 corresponding to a plurality of image forming units 4x, a secondary transfer device 442, and a belt cleaning device 443.

[0055] In each of the image forming units 4x, the charging device 42 charges the surface of the photoreceptor 41. The optical scanning unit 40 forms an electrostatic latent image on the surface of the photoreceptor 41 in each of the image forming units 4x by scanning with laser light.

[0056] In each of the image forming units 4x, the developing device 43 develops the electrostatic latent image into a toner image by supplying toner to the surface of the photoreceptor 41.

[0057] The primary transfer device 441 transfers the toner images on the surface of the photoreceptor 41 of each image forming unit 4x to the surface of the intermediate transfer belt 440. As a result, the toner images of the multiple developing colors are transferred to the surface of the intermediate transfer belt 440. At the print position P5, the primary transfer device 441 transfers the toner images on the surface of the intermediate transfer belt 440 to each of the sheets 9. The fixing device 46 fixes the toner images transferred to each of the sheets 9 by heating and pressurizing them.

[0058] In each of the image forming units 4x, the drum cleaning device 45 removes waste toner remaining on the surface of the photoreceptor 41. The belt cleaning device 443 removes waste toner remaining on the surface of the intermediate transfer belt 440.

[0059] The printing device 4 may be a device that forms images on each of the sheets 9 using a method other than electrophotography. For example, the printing device 4 may be a device that forms images on each of the sheets 9 using an inkjet method.

[0060] If an inkjet printing device 4 is used, the sheet transport device 3 may include a belt transport device that transports each sheet 9 by a rotating endless belt.

[0061] The operating device 801 is a device that accepts human input. The operating device 801 includes, for example, operating buttons and a touch panel. The display device 802 is a device that displays information. The display device 802 includes, for example, a panel display device such as a liquid crystal display unit.

[0062] The control device 8 performs various data processing operations. Furthermore, the control device 8 controls equipment such as the sheet feeding device 2, the sheet transport device 3, the printing device 4, and the display device 802.

[0063] As shown in Figure 2, the control unit 8 includes a CPU (Central Processing Unit) 81, a RAM (Random Access Memory) 82, a secondary storage device 83, and peripheral devices such as a signal interface 84. Furthermore, the control unit 8 also includes a communication device 85.

[0064] The CPU 81 is a processor that performs various data processing and control by executing computer programs. The RAM 82 is a computer-readable volatile memory. The RAM 82 temporarily stores the computer programs executed by the CPU 81 and the data that the CPU 81 outputs and references during the process of performing various processes.

[0065] The secondary storage device 83 is a computer-readable, non-volatile storage device. The secondary storage device 83 is capable of storing and updating the computer program and various types of data. For example, flash memory, a hard disk drive, or both may be used as the secondary storage device 83.

[0066] The signal interface 84 converts signals output by various sensors into digital data and transmits the converted digital data to the CPU 81. Furthermore, the signal interface 84 converts control commands output by the CPU 81 into control signals and transmits the control signals to the controlled device.

[0067] The communication device 85 performs communication with other devices such as a host device via a communication network such as a LAN. The CPU 81 sends and receives data with the other devices via the communication device 85.

[0068] The CPU 81 includes a plurality of processing modules that are realized by executing the computer program. The plurality of processing modules include a feeding control unit 8a, a transport control unit 8b, and a print control unit 8c, among others.

[0069] The feed control unit 8a performs data processing and control related to the sheet feeding device 2. The feed control unit 8a of the CPU 81 constitutes a part of the sheet feeding device 2.

[0070] The transport control unit 8b performs data processing and control related to the sheet transport device 3. The transport control unit 8b of the CPU 81 constitutes a part of the sheet transport device 3.

[0071] The print control unit 8c performs data processing and control related to the printing device 4. The print control unit 8c of the CPU 81 constitutes a part of the printing device 4.

[0072] The supply control unit 8a includes a main processing unit 8d, a timing processing unit 8e, and a state determination unit 8f, among others.

[0073] The main processing unit 8d controls the start and end of the feeding process by controlling the operation and stopping of the feeding motor 230.

[0074] For example, when a print request is input through the operating device 801 or the communication device 85, the main processing unit 8d activates the feed motor 230 to start the feed mechanism 20.

[0075] The print request is either a request to execute a single print process or a request to execute a series of print processes. The single print process is the process of forming an image on one sheet 9. The series of print processes is the process of forming images sequentially on multiple sheets 9.

[0076] The timing processing unit 8e performs a first timing process that measures the elapsed time from the time when the feeding process for each sheet 9 is started until the time when each sheet 9 is detected by the feeding sheet detection device 25. In this embodiment, the time when the feeding motor 230 starts operating is the time when the feeding process is started.

[0077] The timing processing unit 8e is an example of a timing device that performs the first timing process. The timing device may be implemented by other processors such as a DSP (Digital Signal Processor) or by circuits such as an ASIC (Application Specific Integrated Circuit).

[0078] Furthermore, the timing processing unit 8e also performs a second timing process, which measures the elapsed time from the moment each sheet 9 is detected by the sheet feeding detection device 25.

[0079] If the print request is a request to execute the continuous print process, the main processing unit 8d controls the timing of the start of the second and subsequent feeding processes based on the measurement time of the second timing process. As a result, each sheet 9 is fed to the transport path 30 at appropriate intervals.

[0080] The state determination unit 8f executes a process to determine the feeding status of each sheet 9 by the sheet feeding device 2. In this embodiment, the state determination unit 8f determines the feeding status of each sheet 9 by the sheet feeding device 2 based on the measurement time of the first timing process.

[0081] The print control unit 8c controls the process of forming the electrostatic latent image on the surface of the photoreceptor 41 of each of the multiple image forming units 4x by controlling the optical scanning unit 40. In this way, the print control unit 8c controls the timing at which the toner image is formed on the surface of the photoreceptor 41 of each of the multiple image forming units 4x.

[0082] The transport control unit 8b stops the rotation of the resist roller pair 31a in response to the detection of each sheet 9 by the transport sheet detection device 32, and then rotates the resist roller pair 31a in accordance with the timing at which the toner image is formed in each of the multiple image forming units 4x. As a result, the transport control unit 8b executes control to feed each of the sheets 9 from the resist position P4 to the print position P5 in synchronization with the timing at which the toner image is formed in each of the multiple image forming units 4x.

[0083] Incidentally, in the sheet feeding device 2, deterioration of the parts that come into contact with each sheet 9 may cause delays in the feeding of each sheet 9. Specifically, deterioration of the pickup roller 22 or the delivery roller 23 may cause the pickup roller 22 or the delivery roller 23 to slip on the upper surface of each sheet 9, resulting in delays in the feeding of each sheet 9.

[0084] Similarly, in the sheet feeding device 2, separation failures may occur due to deterioration of the parts that come into contact with each sheet 9. This separation failure is a phenomenon in which multiple sheets 9 are fed to the transport path 30 side beyond the retard roller 24 while overlapping. Specifically, deterioration of the retard roller 24 may cause the retard roller 24 to slip on the underside of each sheet 9, resulting in the separation failure.

[0085] Therefore, it is desirable to be able to determine the deterioration state of the components constituting the sheet feeding device 2 without requiring the addition of any equipment.

[0086] In the sheet feeding device 2, the feeding control unit 8a performs sheet feeding control, which will be described later (see Figure 5). This allows the sheet feeding device 2 to determine the deterioration state of the parts without requiring any additional equipment.

[0087] In the following description, one sheet of the stacking sheet 90 that is subject to the paper feeding process will be referred to as the target sheet 9a (see Figures 3 and 4). The target sheet 9a is the topmost sheet of the stacking sheet 90. The target sheet 9a is also the sheet subject to the first timing process and the second timing process.

[0088] Furthermore, the sheet that is subjected to the feeding process after the target sheet 9a in the loading sheet 90 is referred to as the next sheet 9b (see Figure 3). The next sheet 9b is the second sheet from the top in the loading sheet 90.

[0089] [Sheet feeding control] The following describes an example of the sheet feeding control procedure, referring to the flowchart shown in Figure 5. The sheet feeding control is performed by the feeding control unit 8a.

[0090] The sheet feeding control procedure described above is an example of a procedure for implementing a sheet feeding control method for controlling the sheet feeding device 2. The sheet feeding control procedure includes a procedure for implementing a sheet feeding state determination method.

[0091] The CPU 81, including the feed control unit 8a, is an example of a control device that implements the sheet feed control method and a processing device that implements the sheet feed state determination method. The main processing unit 8d starts the sheet feed control when the print request is input through the operating device 801 or the communication device 85.

[0092] In the following description, S101, S102, ... represent identification codes for multiple processes in the sheet feeding control. In the sheet feeding control, the process of process S101 is executed first.

[0093] <Process S101> In step S101, the main processing unit 8d obtains pre-registered sheet size information from the secondary storage device 83. The sheet size information represents the size of the loading sheets 90 stored in the sheet cassette 200.

[0094] For example, the sheet size information includes standard size information selected from a plurality of standard size candidates and sheet orientation information representing the orientation of the loading sheet 90. The standard size information is information that specifies the vertical and horizontal dimensions of the loading sheet 90, and the sheet orientation information represents whether the length of the loading sheet 90 in the sheet feeding direction D1 is the vertical or horizontal dimension.

[0095] That is, the sheet size information includes sheet length information representing the length in the sheet feeding direction D1 of the loaded sheet 90 housed in the sheet cassette 200. The length represented by the sheet length information is the vertical dimension or the horizontal dimension in the standard size information.

[0096] The main processing unit 8d inputs the sheet size information in advance via the operating device 801 or the communication device 85 and registers it in the secondary storage device 83.

[0097] After executing the process in step S101, the main processing unit 8d moves the process to step S102.

[0098] <Process S102> In step S102, the main processing unit 8d determines whether the feeding timing has arrived or not.

[0099] For example, the feeding timing is either the initial feeding timing or the subsequent feeding timing. The initial feeding timing is the timing after the print request has been input and the printer 4 has finished preparing to operate.

[0100] The subsequent feeding timing is the timing at which the feeding of the second and subsequent sheets 9 begins when the print request is a request for the continuous printing process.

[0101] Specifically, the subsequent feeding timing is the timing when the second measurement time corresponding to the previous feeding process reaches the reference waiting time corresponding to the sheet length information. The reference waiting time is the time required from the point when the leading edge of each sheet 9 reaches the detection position P3 until the rear end of each sheet 9 exceeds a predetermined position along the cassette front wall surface 200a by a predetermined amount.

[0102] The main processing unit 8d selects one of several pre-set candidate waiting times corresponding to the sheet length information as the reference waiting time.

[0103] The main processing unit 8d waits until it is determined that the feeding timing has arrived. When it is determined that the feeding timing has arrived, the main processing unit 8d moves the process to step S103.

[0104] <Process S103> In step S103, the main processing unit 8d causes the feeding mechanism 20 to start the feeding process. As a result, the pickup roller 22 and the delivery roller 23 rotate, and the target sheet 9a on the loading sheet 90 is fed from the lift plate 211 toward the transport path 30 (see Figure 3).

[0105] Furthermore, when the feeding process is started in step S103, the timing processing unit 8e starts the first timing process.

[0106] After executing the process in step S103, the main processing unit 8d moves the process to step S104.

[0107] <Process S104> In step S104, the timing processing unit 8e continues the first timing process until the feed sheet detection device 25 transitions from a non-detection state to a sheet detection state.

[0108] The timing processing unit 8e terminates the first timing process when the feed sheet detection device 25 transitions to the sheet detection state. As a result, the timing processing unit 8e determines the target measurement time T1a, which is the result of the first timing process for the target sheet 9a (see Figures 8-11).

[0109] Figures 8-11 show an example of how the target measurement time T1a changes depending on the number of feeding cycles when the feeding process is repeated.

[0110] After executing the process in step S104, the timing processing unit 8e moves the process to step S105.

[0111] <Process S105> In step S105, the timing processing unit 8e starts the second timing process.

[0112] After executing the process in step S105, the main processing unit 8d moves the process to step S106.

[0113] Furthermore, while the processes from step S105 onward are being executed, the transport control unit 8b instructs the sheet transport device 3 to transport the target sheet 9a along the transport path 30, and the print control unit 8c instructs the print device 4 to form an image on the target sheet 9a.

[0114] <Process S106> In step S106, the state determination unit 8f selects the following process depending on whether the feeding process performed in step S103 corresponds to one or more standard feeding processes that satisfy predetermined standard feeding conditions.

[0115] The aforementioned standard feeding conditions are conditions that indicate a situation in which there is no positional deviation of the target sheet 9a relative to the initial reference position P1 at the time the feeding process is started, or where the positional deviation is assumed to be negligibly small.

[0116] The next sheet 9b may be sent out as the accompanying sheet from the initial reference position P1 in the sheet feeding direction D1 when the feeding process is executed (see Figure 3). In this case, the position of the next sheet 9b is shifted in the sheet feeding direction D1 relative to the initial reference position P1. The next sheet 9b, which has experienced a positional shift, is fed as a new target sheet 9a in the next feeding process.

[0117] When the target sheet 9a with the aforementioned misalignment is fed, the target measurement time T1a is smaller compared to when the target sheet 9a without the misalignment is fed. Figures 8 and 9 show an example in which, because the misalignment of the next sheet 9b occurred in the fifth feeding process, the target measurement time T1a in the sixth feeding process was smaller than the measurement time T1 in the fifth feeding process.

[0118] Furthermore, Figures 9 to 11 show examples where the positional displacement of the target sheet 9a increases as the number of feeding processes increases. As shown in Figures 8 to 11, when the number of feeding processes after the lift mechanism 21 lifts the loaded sheet 90 to the contact position is small, the positional displacement of the target sheet 9a is often not present or is small.

[0119] In this embodiment, the standard feeding conditions include a count condition that the feeding process is either a predetermined one or predetermined multiple feeding processes after the lift mechanism 21 lifts the loading sheet 90 to the contact position.

[0120] For example, the count condition is that the feeding process is performed for the first or second time after the lift mechanism 21 lifts the loading sheet 90 to the contact position. Alternatively, the count condition is that the feeding process is performed from the ith to the jth time after the lift mechanism 21 lifts the loading sheet 90 to the contact position. i and j are, for example, positive integers less than 10.

[0121] In addition, during the first feeding process when the lift mechanism 21 has lifted the loading sheet 90 to the contact position, a relatively long target measurement time T1a may be measured. Therefore, it is possible to exclude the first feeding process from the count condition.

[0122] Furthermore, the standard feeding conditions may be the logical AND of the mounting conditions for mounting the sheet cassette 200 and the number of times conditions. The mounting conditions are those that result from the lift mechanism 21 lifting the loaded sheet 90 to the contact position for the first time after the detection result of the mounting detection device 26 changes from the unmounted state to the mounted state, and that are the one or more feeding processes performed.

[0123] The lift mechanism 21 lowers the loading sheet 90 from the contact position to the separation position before the sheet cassette 200 is pulled out from the lower housing 1a. Normally, when the sheet cassette 200 is pulled out from the lower housing 1a, an operation to replenish the loading sheet 90 or to align the loading sheet 90 is performed.

[0124] Therefore, under conditions where both the mounting conditions and the number of times conditions are met, the likelihood of the positional displacement of the target sheet 9a not occurring increases.

[0125] The state determination unit 8f moves the process to process S107 if the feeding process performed in process S103 is the standard feeding process. On the other hand, the state determination unit 8f moves the process to process S108 if the feeding process performed in process S103 does not correspond to one or more standard feeding processes.

[0126] <Process S107> In step S107, the state determination unit 8f derives a standard feeding time TFS1 based on one or more target measurement times T1a measured when the standard feeding process is executed once or more times.

[0127] For example, the state determination unit 8f derives one target measurement time T1a measured when the standard feeding process is executed once as the standard feeding time TFS1.

[0128] Alternatively, the state determination unit 8f sets a representative value of the multiple target measurement times T1a measured when the standard feeding process is executed multiple times as the standard feeding time TFS1. For example, the representative value of the multiple target measurement times T1a is the average, minimum, or median of the multiple target measurement times T1a.

[0129] Furthermore, the state determination unit 8f records the information of the set reference feeding time TFS1 in the secondary storage device 83, associating it with the sheet length information of the sheet size information obtained in process S101.

[0130] The reference feeding time TFS1 is the reference value of the target measurement time T1a in the feeding process under conditions where the positional misalignment of the target sheet 9a does not occur, or the positional misalignment is assumed to be negligibly small.

[0131] The standard feeding time TFS1 set in process S107 is the time corresponding to the sheet length information of the sheet size information obtained in process S101. The state determination unit 8f records the standard feeding time TFS1 in association with the sheet length information obtained in process S101.

[0132] The reference feeding time TFS1 is used to determine whether or not positional misalignment occurs in each of the sheets 9, and to derive the amount of positional misalignment. The amount of positional misalignment is the amount of positional misalignment of each sheet 9 relative to the initial reference position P1 at the time the feeding process for each sheet 9 is started.

[0133] The initial value of the standard feeding time TFS1 is the default standard time. The default standard time is determined by the design feeding speed of the feeding mechanism 20 and the path length from the initial reference position P1 to the detection position P3.

[0134] One or more target measurement times T1a measured by the timing processing unit 8e when the standard feeding process is executed once or more times are examples of one or more standard measurement times. In this embodiment, one or more of the standard measurement times are used to derive the standard feeding time TFS1.

[0135] In step S108, described later, the target measurement time T1a is the time measured by the timing processing unit 8e for the target sheet 9a that is fed after one or more of the reference feeding sheets have been fed. From the time the processing of step S107 is executed until the processing of step S108 is executed, the lift mechanism 21 holds the loaded sheet 90 in the contact position.

[0136] The state determination unit 8f executes the process in step S107 and then moves the process to step S108.

[0137] <Process S108> In step S108, the state determination unit 8f executes the feeding state determination process described later (see Figure 6). The feeding state determination process is a process that derives feeding parameters that represent the feeding state of each sheet 9.

[0138] As will be described later, the feeding parameters include the positional displacement amount and the target feeding time TF1 (see Figures 8-12). The target feeding time TF1 is the time required to feed the target sheet 9a from the initial reference position P1 to the detection position P3.

[0139] The delay time TD1 is the difference between the target feeding time TF1 and the reference feeding time TFS1 (see Figures 8-12). The delay time TD1 represents the degree of feeding delay caused by the pickup roller 22 or the delivery roller 23 sliding on the upper surface of each sheet 9.

[0140] The state determination unit 8f executes the process in step S108 and then moves the process to step S109.

[0141] <Process S109> In step S109, the main processing unit 8d selects the following process depending on whether all the feeding processes corresponding to the print request have been completed.

[0142] The main processing unit 8d moves the process to step S102 if all the feeding processes corresponding to the print request have not yet been completed. In this case, in step S102, the main processing unit 8d executes a process to determine the subsequent feeding timing based on the result of the second timing process started in step S105.

[0143] On the other hand, when all the feeding processes corresponding to the print request have been completed, the main processing unit 8d moves the process to step S110.

[0144] <Process S110> In step S110, the state determination unit 8f executes a component deterioration determination process, which will be described later (see Figure 7). The component deterioration determination process determines the deterioration state of the components constituting the feeding mechanism 20 based on the results of the feeding parameter derivation process performed by the feeding state determination process.

[0145] After the state determination unit 8f has executed the process of step S110, the main processing unit 8d terminates the sheet feeding control.

[0146] [Feeding status determination process] Next, an example of the procedure for the feeding state determination process will be described with reference to the flowchart shown in Figure 6. The feeding state determination process is performed by the state determination unit 8f.

[0147] The procedure for determining the feeding state described above is an example of a procedure for implementing the sheet feeding state determination method. The CPU 81, which includes the state determination unit 8f, is an example of the processing unit that implements the sheet feeding state determination method.

[0148] In the following description, S201, S202, ... represent identification codes for multiple processes in the feeding state determination process. In the feeding state determination process, the process of process S201 is executed first.

[0149] <Process S201> In process S201, the state determination unit 8f selects the following process by comparing the target measurement time T1a with the reference feeding time TFS1.

[0150] The state determination unit 8f proceeds to process S202 if the target measurement time T1a is less than the standard feeding time TFS1. On the other hand, the state determination unit 8f proceeds to process S207 if the target measurement time T1a is not less than the standard feeding time TFS1.

[0151] A state in which the target measurement time T1a is less than the standard feeding time TFS1 is a positional misalignment state in which the target sheet 9a is located downstream of the initial reference position P1 in the sheet feeding direction D1 at the time the feeding process of the target sheet 9a is started. A state in which the target measurement time T1a is not less than the standard feeding time TFS1 is a non-positional misalignment state in which the positional misalignment state does not occur.

[0152] <Process S202> In step S202, the state determination unit 8f selects the following process depending on whether or not a continuous positional misalignment state has occurred. Figures 10 to 12 show an example of the continuous positional misalignment state.

[0153] The aforementioned continuous positional misalignment state is a condition in which one or more recent measurement times T1x and the target measurement time T1a are less than the reference feed time TFS1.

[0154] One or more recent measurement times T1x are the times measured by the first timing process of the timing processing unit 8e for one or more consecutive recent feed sheets 9x that are fed immediately before the feeding of the target sheet 9a.

[0155] Figure 10 shows an example where, when the target measurement time T1a is the measurement time T1 obtained in the 7th feeding process, the most recent measurement time T1x obtained in the previous feeding process and the target measurement time T1a are both lower than the reference feeding time TFS1.

[0156] Figure 11 shows an example where the target measurement time T1a is the measurement time T1 obtained in the 9th feeding process, and the three most recent measurement times T1x obtained in the feeding process three processes ago and the previous feeding process, as well as the target measurement time T1a, are all below the reference feeding time TFS1.

[0157] Figure 12 shows an example where the target measurement time T1a is the measurement time T1 obtained in the 10th feeding process, and the four most recent measurement times T1x obtained in the feeding process four processes ago and the previous feeding process, as well as the target measurement time T1a, are all below the reference feeding time TFS1.

[0158] The state determination unit 8f proceeds to process S203 if the continuous positional misalignment state does not occur. On the other hand, the state determination unit 8f proceeds to process S204 if the continuous positional misalignment state occurs.

[0159] <Process S203> In step S203, the state determination unit 8f executes a first position deviation derivation process. The first position deviation derivation process is a process that derives the amount of position deviation according to the difference between the target measurement time T1a and the reference feeding time TFS1.

[0160] The first positional deviation derivation process includes a process of deriving the difference between the target measurement time T1a and the reference feeding time TFS1 as the positional deviation time TG1 (see Figures 9 and 10). Furthermore, the first positional deviation derivation process includes a process of deriving the amount of positional deviation by multiplying the positional deviation time TG1 by the reference feeding speed. Note that the positional deviation time TG1 may also be derived as the amount of positional deviation.

[0161] The aforementioned standard feeding speed is derived by dividing the path length from the initial reference position P1 to the detection position P3 by the standard feeding time TFS1. The state determination unit 8f may derive the standard feeding speed in advance in step S107.

[0162] The state determination unit 8f executes the process in step S203 and then moves the process to step S206.

[0163] <Process S204> On the other hand, in step S204, the state determination unit 8f identifies the shortest measurement time TMN1, which is the shortest time among one or more recent measurement times T1x and target measurement time T1a (see Figures 10-12).

[0164] The state determination unit 8f executes the process in step S204 and then moves the process to step S205.

[0165] <Process S205> In step S205, the state determination unit 8f executes a second positional deviation derivation process. The second positional deviation derivation process is a process that derives the amount of positional deviation according to the difference between the target measurement time T1a and the shortest measurement time TMN1.

[0166] The second positional deviation derivation process includes a process of deriving the difference between the target measurement time T1a and the shortest measurement time TMN1 as the positional deviation time TG1 (see Figure 11). Furthermore, the second positional deviation derivation process includes a process of deriving the amount of positional deviation by multiplying the positional deviation time TG1 by the reference feeding speed.

[0167] In most cases, after the misalignment of each sheet 9 occurs, the amount of misalignment increases with each subsequent feeding process until the leading edge of each sheet 9 reaches the retard roller 24. Typically, the misalignment of each sheet 9 is not resolved by the feeding process.

[0168] On the other hand, even if the amount of positional displacement does not change, the target measurement time T1a may be lengthened due to the pickup roller 22 and the delivery roller 23 sliding on the upper surface of the target sheet 9a.

[0169] The second positional misalignment derivation process is a process that derives the positional misalignment amount under the assumption that the shortest measurement time TMN1 represents the reduction in feeding time caused by the positional misalignment amount of the target sheet 9a when the continuous positional misalignment state occurs.

[0170] The state determination unit 8f executes the process in step S205 and then moves the process to step S206.

[0171] <Process S206> In process S206, the state determination unit 8f derives the target feeding time TF1 by adding the positional deviation time TG1 to the target measurement time T1a (see Figures 9-12).

[0172] The target feeding time TF1 is the time obtained by correcting the target measurement time T1a with the positional deviation time TG1, and the positional deviation time TG1 is the time required to feed the target sheet 9a by a distance corresponding to the amount of positional deviation.

[0173] The target feeding time TF1 derived in process S206 is the time required to feed the target sheet 9a from the initial reference position P1 to the detection position P3 when the target sheet 9a is in the misaligned position state.

[0174] Furthermore, the process in step S206, which is executed after the process in step S203, is an example of a process that derives the target feeding time TF1 by correcting the target measurement time T1a according to the difference between the target measurement time T1a and the reference feeding time TFS1.

[0175] Furthermore, the process in step S206, which is executed after the processes in steps S204 and S205, is an example of a process that derives the target feeding time TF1 by correcting the target measurement time T1a according to the difference between the target measurement time T1a and the shortest measurement time TMN1.

[0176] The state determination unit 8f terminates the feeding state determination process after executing the process in step S206.

[0177] <Process S207> On the other hand, in step S207, the state determination unit 8f derives the target measurement time T1a as the target feeding time TF1. The target feeding time TF1 derived in step S207 is the time required to feed the target sheet 9a from the initial reference position P1 to the detection position P3 when the target sheet 9a is in the non-misaligned state.

[0178] Processes S206 and S207 are examples of processes that derive the target feeding time TF1 based on the target measurement time T1a.

[0179] The state determination unit 8f terminates the feeding state determination process after executing the process of step S207.

[0180] [Component degradation detection process] Next, an example of the procedure for the component degradation determination process will be described with reference to the flowchart shown in Figure 7. The component degradation determination process is performed by the state determination unit 8f.

[0181] The procedure for determining component deterioration is an example of a procedure for implementing the sheet feeding state determination method. The CPU 81, which includes the state determination unit 8f, is an example of the processing unit that implements the sheet feeding state determination method.

[0182] In the following description, S301, S302, ... represent identification codes for multiple steps in the component degradation determination process. In the component degradation determination process, the process of step S301 is executed first.

[0183] <Process S301> In step S301, the state determination unit 8f determines the delay state of feeding the target sheet 9a by comparing the target feeding time TF1 obtained in step S206 or step S207 with a preset delay determination time TDS1 (see Figures 8-12).

[0184] The delay determination time TDS1 is set based on the predetermined reference time.

[0185] In step S301, the state determination unit 8f selects a delay determination time TDS1 corresponding to the sheet length information of the size information from a plurality of candidate reference times. The processing in step S301 is an example of the process of selecting a delay determination time TDS1 corresponding to the size information from a plurality of candidate determination times.

[0186] The state determination unit 8f counts the number of delays, which is the number of times a delay state occurs, when the target feeding time TF1 exceeds the delay determination time TDS1. The delay count is the number of times when the target feeding time TF1 exceeds the delay determination time TDS1.

[0187] In step S301, the state determination unit 8f may count a plurality of individual delay counts, each of which is the number of delays.

[0188] The aforementioned number of individual delays is the number of times the target feed time TF1 exceeds each of the individual delay determination times. Each of the aforementioned individual determination times is an example of a delay determination time TDS1, and is a time that is equal to or greater than the reference feed time TFS1. As a result, the delay state of each feed in Sheet 9 is divided into multiple delay levels according to the aforementioned individual delay determination times, and the number of individual delays corresponding to each of the aforementioned delay levels is counted.

[0189] In step S301, the state determination unit 8f may count the first delay count and the second delay count.

[0190] The first delay count is the number of times when the amount of positional deviation does not exceed the positional deviation judgment value, and the target measurement time T1a exceeds the delay judgment time TDS1. The second delay count is the number of times when the amount of positional deviation exceeds the positional deviation judgment value, and the target measurement time T1a exceeds the delay judgment time TDS1.

[0191] The state determination unit 8f executes the process in step S301 and then moves the process to step S302.

[0192] <Process S302> In step S302, the state determination unit 8f determines the positional displacement state of the target sheet 9a by comparing the positional displacement amount derived in step S203 or step S205 with the positional displacement determination value and the separation failure determination value, respectively.

[0193] The separation failure determination value is set in accordance with the path length from the initial reference position P1 to the separation position P2. For example, the separation failure determination value is the path length from the initial reference position P1 to the separation position P2 plus a predetermined correction value. Alternatively, the path length from the initial reference position P1 to the separation position P2 may be set as the separation failure determination value. The positional deviation determination value is a value smaller than the separation failure determination value.

[0194] Specifically, the state determination unit 8f counts the number of separation failures when the amount of positional misalignment exceeds the separation failure determination value. The number of separation failures is the number of times when the amount of positional misalignment exceeds the separation failure determination value.

[0195] If the amount of misalignment exceeds the separation failure determination value, it is considered that a separation failure has occurred in the target sheet 9a. The separation failure is a state in which the leading edge of the target sheet 9a has reached the separation position P2 or a position downstream of the separation position P2 in the sheet feeding direction D1 at the start of the feeding process.

[0196] In step S302, the state determination unit 8f may count a plurality of individual separation failure counts, each of which is the number of separation failures.

[0197] The number of times each of the multiple individual separation failures occurs is the number of times the positional displacement exceeds each of the multiple individual separation failure judgment values. Each of the multiple individual separation failure judgment values ​​is an example of the separation failure judgment value. As a result, the separation failure state of each sheet 9 is divided into multiple separation failure degrees according to the multiple individual separation failure judgment values, and the number of times each of the multiple individual separation failures that corresponds to each of the multiple separation failure degrees is counted.

[0198] In step S302, the state determination unit 8f may derive a positional misalignment excess amount, which represents the amount by which the positional misalignment exceeds the separation failure determination value. Specifically, the positional misalignment excess amount is the difference between the positional misalignment amount and the separation failure determination value.

[0199] Furthermore, the state determination unit 8f counts the number of misalignments if the amount of misalignment does not exceed the separation failure determination value and exceeds the misalignment determination value. On the other hand, the state determination unit 8f counts the number of non-misalignments if the amount of misalignment does not exceed the misalignment determination value.

[0200] The number of misaligned positions is an example of the number of times the amount of misalignment exceeds the misalignment determination value. The number of non-misaligned positions is the number of times the amount of misalignment does not exceed the misalignment determination value.

[0201] The positional misalignment state for which the number of positional misalignments is counted is the state in which the leading edge of the target sheet 9a at the start of the feeding process has reached a predetermined range between the initial reference position P1 and the detection position P3.

[0202] The state determination unit 8f executes the process in step S302 and then moves the process to step S303.

[0203] <Process S303> In step S303, the state determination unit 8f counts the number of feeding operations, which is the number of feeding operations.

[0204] The state determination unit 8f executes the process in step S303 and then moves the process to step S304.

[0205] <Process S304> In step S304, the state determination unit 8f records feed performance data, which includes information on the actual feed conditions of various feed states obtained in steps S301 to S303, in the secondary storage device 83.

[0206] Specifically, the status determination unit 8f records the feeding performance data, including information on the number of feeding cycles, the number of delays, and the number of separation failures, in the secondary storage device 83.

[0207] The status determination unit 8f may further record the feed and transfer performance data, including information on the number of individual delays, in the secondary storage device 83.

[0208] The status determination unit 8f may further record the feeding performance data, including information on the first delay count and the second delay count, in the secondary storage device 83.

[0209] The state determination unit 8f may further record the feeding performance data, including information on the number of positional deviations and the number of non-positional deviations, in the secondary storage device 83.

[0210] The status determination unit 8f may further record the feeding performance data, including information on the number of times each individual separation failed, in the secondary storage device 83.

[0211] The state determination unit 8f may further record the feeding performance data, including information on the excess positional deviation, in the secondary storage device 83. In this case, the feeding performance data is an example of the actual data on the excess positional deviation.

[0212] The state determination unit 8f executes the process in step S304 and then moves the process to step S305.

[0213] <Process S305> In step S305, the state determination unit 8f performs a deterioration determination of the supplied parts based on the supply performance data.

[0214] In this embodiment, the feeding components are a pickup roller 22 and a delivery roller 23. In the following description, the state in which the degree of deterioration of the feeding components is determined to be outside the acceptable range is referred to as the feeding component deterioration state. The degree of deterioration of the feeding components is an example of the determination result of the deterioration state of the feeding mechanism 20.

[0215] For example, the state determination unit 8f determines that the supply component deterioration state has occurred when the number of delays exceeds a preset delay threshold.

[0216] Furthermore, a plurality of individual delay count thresholds corresponding to each of the plurality of individual delay counts may be set in advance. In this case, the state determination unit 8f determines that the supply component deterioration state has occurred when each of the plurality of individual delay counts exceeds each of the plurality of individual delay count thresholds.

[0217] Furthermore, the state determination unit 8f may determine that the feeding component deterioration state has occurred when the first delay count exceeds a preset first delay count threshold. Similarly, the state determination unit 8f may determine that the feeding component deterioration state has occurred when the second delay count exceeds a preset second delay count threshold.

[0218] Furthermore, the state determination unit 8f may determine that the feeding component deterioration state has occurred when the frequency of the first delay count relative to the number of non-positional misalignment counts exceeds a preset first delay frequency threshold. Similarly, the state determination unit 8f may determine that the feeding component deterioration state has occurred when the frequency of the second delay count relative to the number of positional misalignment counts exceeds a preset second delay frequency threshold.

[0219] By using the first and second delay counts in the degradation determination, it becomes possible to perform a detailed degradation determination that reflects the difference in the relationship between the frequency of feed delays and component degradation, depending on the magnitude of the positional deviation.

[0220] The state determination unit 8f determines that the degree of deterioration of the feeding component is outside the acceptable range, and proceeds to process S306. On the other hand, the state determination unit 8f determines that the degree of deterioration of the feeding component is not outside the acceptable range, and proceeds to process S307.

[0221] <Process S306> In step S306, the status determination unit 8f outputs a feed component deterioration alarm through either or both of the display device 802 and the communication device 85. The feed component deterioration alarm is an alarm that prompts maintenance or replacement of the feed component.

[0222] For example, the status determination unit 8f displays the information about the feed component deterioration alarm on the display device 802. Alternatively, the status determination unit 8f may transmit the information about the feed component deterioration alarm to the administrator's terminal via the communication device 85.

[0223] The display device 802 and the communication device 85 are examples of information output devices.

[0224] The state determination unit 8f executes the process in step S306 and then moves the process to step S307.

[0225] <Process S307> In step S307, the state determination unit 8f performs a deterioration determination of the separated parts based on the feeding performance data.

[0226] In this embodiment, the separation component is a retard roller 24. In the following description, the state in which the degree of deterioration of the separation component is determined to be outside the acceptable range is referred to as the deterioration state of the separation component. The degree of deterioration of the separation component is an example of the determination result of the deterioration state of the feeding mechanism 20.

[0227] For example, the state determination unit 8f determines that the separated component has deteriorated if the number of separation failures exceeds a preset threshold for the number of separation failures.

[0228] Furthermore, the state determination unit 8f may determine that the separated component is degraded if the frequency of the number of separation failures relative to the number of feeding cycles exceeds the first frequency threshold.

[0229] Furthermore, the state determination unit 8f may determine that the separated component has deteriorated if the frequency of the number of separation failures relative to the number of positional misalignments exceeds the second frequency threshold.

[0230] Furthermore, the state determination unit 8f may determine that the separated component deterioration state has occurred when the representative value of the actual value of the excess positional deviation exceeds the excess threshold. For example, the representative value of the actual value of the excess positional deviation is the maximum or average value of the actual value of the excess positional deviation.

[0231] Furthermore, multiple individual separation failure thresholds corresponding to the number of individual separation failures may be set in advance. In this case, the state determination unit 8f determines that the separated component deterioration state has occurred when each of the multiple individual separation failures exceeds each of the multiple individual separation failure thresholds.

[0232] The state determination unit 8f proceeds to process S308 if it determines that the degree of deterioration of the separated part is outside the acceptable range. On the other hand, the state determination unit 8f terminates the part deterioration determination process if it determines that the degree of deterioration of the separated part is not outside the acceptable range.

[0233] <Process S308> In step S308, the status determination unit 8f outputs a separated component deterioration alarm through either or both of the display device 802 and the communication device 85. The separated component deterioration alarm is an alarm that prompts maintenance or replacement of the separated component.

[0234] For example, the status determination unit 8f displays the information about the separated component deterioration alarm on the display device 802. Alternatively, the status determination unit 8f may transmit the information about the separated component deterioration alarm to the administrator's terminal via the communication device 85.

[0235] By executing the feeding state determination process and the component deterioration determination process, it is possible to determine the deterioration state of the feeding components and the separated components in the sheet feeding device 2 without requiring the addition of any equipment.

[0236] [First variation] Next, a first modified example of the sheet feeding control will be described with reference to the flowchart shown in Figure 13.

[0237] The sheet feeding control procedure in this modified example includes steps S111 and S112, which are added to the sheet feeding control procedure shown in Figure 5. The differences between this modified example and the sheet feeding control procedure shown in Figure 5 will be explained below.

[0238] <Process S104> In step S104 of this modified example, the timing processing unit 8e moves the process to step S105 when the sheet feeding detection device 25 transitions from a non-detection state to a sheet detection state.

[0239] In step S104 of this modified example, the timing processing unit 8e proceeds to step S111 if the sheet feeding detection device 25 does not transition from the sheet non-detection state to the sheet detection state.

[0240] <Process S111> In step S111, the timing processing unit 8e selects the following process depending on whether the timing time from the first timing process exceeds a preset upper limit. The upper limit is the time used to detect an empty feed state in which the feeding mechanism 20 cannot feed the target sheet 9a.

[0241] The timing processing unit 8e moves the process to step S104 if the timing time from the first timing process does not exceed the upper limit time. As a result, the timing processing unit 8e continues the first timing process until the feed sheet detection device 25 transitions from the sheet non-detection state to the sheet detection state, provided that the timing time from the first timing process does not exceed the upper limit time.

[0242] On the other hand, if the timing time from the first timing process exceeds the upper limit time while the feed sheet detection device 25 does not transition to the sheet detection state, the timing processing unit 8e moves the process to step S112.

[0243] <Process S112> In step S112, the main processing unit 8d outputs an error notification indicating that the empty feed condition has occurred, through either or both of the display device 802 and the communication device 85.

[0244] After executing the process in step S112, the main processing unit 8d terminates the feeding control. As a result, the feeding control is stopped.

[0245] In this modified example, the delay determination time TDS1 and the plurality of individual delay determination times referenced in step S301 are shorter than the upper limit time.

[0246] Furthermore, the print control unit 8c generates page image data corresponding to the target sheet 9a each time the feeding process is executed, and causes each of the image forming units 4x of the printing device 4 to generate a toner image based on the page image data.

[0247] Furthermore, the print control unit 8c causes the print device 4 to perform an image discard process when the timing time of the first timing process for the target sheet 9a reaches a preset discard time. The discard time is shorter than the upper limit time.

[0248] The aforementioned image discarding process is a process in which the toner image corresponding to the target sheet 9a is recovered as waste toner by either or both of the drum cleaning device 45 and the belt cleaning device 443 without being transferred to the target sheet 9a.

[0249] When the print control unit 8c causes the print device 4 to perform the image discarding process, it causes each of the image forming units 4x to regenerate the toner image based on the page image data when the regeneration timing arrives.

[0250] In this modified example, the regeneration timing is the timing at which the sheet feeding detection device 25 transitions from a non-detection state to a sheet detection state.

[0251] For example, the delay determination time TDS1 referenced in process S301 is set to a time that is greater than or equal to the discard time and less than the upper limit time. In addition, the multiple individual delay determination times referenced in process S301 are set to a time that is greater than or equal to the discard time and less than the upper limit time.

[0252] By setting the delay determination time TDS1 and the multiple individual delay determination times to less than the upper limit time, deterioration of the feeding component is detected before the feeding component deteriorates to the point of causing the dry feeding condition.

[0253] Incidentally, if the aforementioned image discarding process occurs frequently, the performance of the continuous printing process in the image forming apparatus 10 will decrease.

[0254] Therefore, the delay determination time TDS1 referenced in step S301 and the plurality of individual delay determination times may be set to a time shorter than the discard time. In this case, deterioration of the feeding component is detected before the image discard process occurs frequently.

[0255] [Second variation] Next, a second modified example of the sheet feeding control will be described.

[0256] As described above, in step S107, the state determination unit 8f derives a standard feeding time TFS1 based on one or more target measurement times T1a measured by the timing processing unit 8e for one or more target sheets 9a that are fed when the standard feeding process that satisfies the standard feeding conditions is executed (see Figure 5).

[0257] On the other hand, in step S107 of this modified example, the state determination unit 8f derives a target feeding time TF1 based on one or more target measurement times T1a measured by the timing processing unit 8e when the reference feeding process is executed once or more times (see Figure 5). As described above, the target feeding time TF1 is used to determine the delay state of the feeding process.

[0258] One or more target measurement times T1a measured when the aforementioned standard feeding process is executed once or multiple times are examples of one or more standard measurement times.

[0259] For example, the state determination unit 8f sets one target measurement time T1a measured when the standard feeding process is executed once as the target feeding time TF1.

[0260] Alternatively, the state determination unit 8f derives a representative value of the multiple target measurement times T1a measured when the standard feeding process is executed multiple times as the target feeding time TF1. For example, the representative value of the multiple target measurement times T1a is the average, minimum, or median of the multiple target measurement times T1a.

[0261] In step S301 of this modified example, the state determination unit 8f counts the number of times the target feeding time TF1 set in step S107 exceeds the delay determination time TDS1 as the delay count (see Figure 7).

[0262] In step S301 of this modified example, the state determination unit 8f may count some or all of the multiple individual delay counts, the first delay count, and the second delay count based on the target feeding time TF1 set in step S107.

[0263] In this modified example, the state determination unit 8f determines the deterioration state of the feeding component based on the number of delays counted as described above or the number of individual delays. This process is the process of step S305.

[0264] [Third variation] Next, a third modified example of the sheet feeding control will be described.

[0265] In this modified example, the main processing unit 8d causes the sheet feeding device 2 to perform an initial feeding process when a predetermined initial setting instruction is input. In the initial feeding process, the lift mechanism 21 lifts the loaded sheet 90 from the separation position to the contact position, and the feeding mechanism 20 then performs the feeding process a predetermined number of times.

[0266] The initial setup instructions are input to the control device 8 via the operating device 801 or the communication device 85. For example, the initial setup instructions are input when the image forming apparatus 10 is being adjusted for shipment, or when parts such as the pickup roller 22 and the delivery roller 23 in the feeding mechanism 20 are replaced with new ones.

[0267] In other words, the initial setting instruction is entered when the feeding mechanism 20 is not deteriorated and there is no delay in feeding.

[0268] The number of initial settings is predetermined to be one or more times. When the initial feeding process is executed, one or more initial feeding sheets are fed. Furthermore, one or more initial measurement times are obtained for one or more of the initial feeding sheets, measured by the timing processing unit 8e.

[0269] In this modified example, the state determination unit 8f sets the delay determination time TDS1 based on one or more of the initial measurement times.

[0270] For example, the state determination unit 8f sets one of the initial measurement times measured in the first or second feeding process as the delay determination time TDS1.

[0271] Alternatively, the state determination unit 8f sets a representative value of the multiple initial measurement times measured in the feeding process executed from the i-th to the j-th time in the initial feeding process as the delay determination time TDS1. For example, the representative value of the multiple initial measurement times is the average, minimum, or median of the multiple initial measurement times.

[0272] For example, each time the initial setting instruction is input, the main processing unit 8d acquires the sheet size information and sets a delay determination time TDS1 for each sheet length information of the sheet size information.

[0273] Further, the state determination unit 8f may set, as the delay determination time TDS1, a time obtained by performing a predetermined correction on the initial measurement time or the representative value.

[0274] [Fourth Modification Example] Next, a fourth modification example of the sheet feeding control will be described.

[0275] In each of steps S206 and S207 in this modification example, the state determination unit 8f derives the difference between the target feeding time TF1 and the reference feeding time TFS1 as the delay time TD1 in the feeding process of the target sheet 9a.

[0276] In step S301 in this modification example, the delay state is determined by comparing the delay time TD1 with a delay time threshold. The delay time threshold is a determination time set instead of the delay determination time TDS1 to be compared with the target feeding time TF1.

[0277] <舍 [Supplementary Note of the Invention] Hereinafter, a summary of the invention extracted from the above-described embodiments will be appended. Note that each configuration and each processing function described in the following supplementary note can be arbitrarily combined by selection.

[0278] [Supplementary Note 1] A feeding mechanism including a feeding rotating body that contacts the upper surface of the uppermost sheet in the stacked sheets, a delivery rotating body arranged at an interval from the feeding rotating body, and a separating member arranged below the delivery rotating body and biased toward the delivery rotating body, and performing a feeding process of feeding each sheet from the stacked sheets to a conveyance path by rotating the feeding rotating body and the delivery rotating body, and separating an accompanying sheet sent out along with each sheet from each sheet by the separating member, A sheet detection device that detects each of the sheets at a detection position downstream of the sheet feeding direction relative to the feed rotating body and the separating member, A sheet feeding state determination method for determining the state of a sheet feeding device, comprising a timing device that measures the elapsed time from the time the feeding process for each sheet is started until the time each sheet is detected by the sheet detection device, The processing device derives a positional deviation amount, which represents the amount of deviation of the target sheet's position from its initial reference position at the start of the feeding process, based on the target measurement time measured by the timing device and a preset reference feeding time for the target sheet being fed by the feeding process. The processing apparatus counts the number of times the positional deviation exceeds a separation failure determination value corresponding to the path length from the initial reference position to the separation member, A method for determining the sheet feeding state, comprising the processing apparatus determining the deterioration state of the feeding mechanism based on the number of separation failures.

[0279] <Note 2> The processing apparatus records actual data of the excess positional deviation amount, which represents the amount by which the positional deviation amount exceeds the separation failure judgment value. The sheet feeding state determination method according to Appendix 1, wherein the processing apparatus determines the deterioration state of the feeding mechanism based on actual data of the number of separation failures and the amount of positional misalignment.

[0280] <Note 3> The processing apparatus counts the number of times the positional displacement exceeds the number of individual separation failures, each of which is a separation failure determination value. The sheet feeding state determination method according to Appendix 1 or Appendix 2, wherein the processing apparatus determines the deterioration state of the feeding mechanism based on the number of individual separation failures.

[0281] <Note 4> The processing apparatus counts the number of misalignment counts, which is the number of times the misalignment amount exceeds a misalignment determination value that is smaller than the separation failure determination value. A sheet feeding state determination method according to any one of the appendices 1 to 3, comprising the processing apparatus determining the deterioration state of the feeding mechanism based on the frequency of the number of separation failures relative to the number of positional misalignments.

[0282] <Note 5> The processing device counts the number of feeding operations, which is the number of feeding operations. A sheet feeding state determination method according to any one of the appendices 1 to 4, comprising the processing apparatus determining the deterioration state of the feeding mechanism based on the frequency of the number of separation failures relative to the number of feeding cycles.

[0283] <Note 6> When the sheet feeding device includes a lift mechanism that lifts the loaded sheets to a contact position where the upper surface of the topmost sheet in the loaded sheets contacts the feeding rotating body, The processing device derives the standard feeding time based on one or more standard feeding processes measured by the timing device when one or more standard feeding processes are performed that satisfy the count condition, which is one or more feeding processes performed a predetermined number of times after the lift mechanism lifts the loaded sheet to the contact position. A sheet feeding state determination method according to any one of the appendices 1 to 5, comprising the processing device performing a first position deviation derivation process that derives the position deviation amount according to the difference between the target measurement time and the reference feeding time.

[0284] <Note 7> When there is no continuous positional deviation state in which one or a plurality of immediately preceding feeding times measured by the timing device for one or a plurality of immediately preceding feeding sheets fed immediately before the target sheet is fed and the target measurement time are less than the reference feeding time, the processing device executes the first positional deviation derivation process. When the continuous positional deviation state occurs, the processing device executes a second positional deviation derivation process for deriving the amount of positional deviation according to the difference between the shortest time of the immediately preceding measurement time and the target measurement time and the reference feeding time, which is included in the sheet feeding state determination method according to appended note 6.

[0285] <Appended Note 8> The sheet feeding device A sheet storage unit that supports the lift mechanism, stores the stacked sheets, and is detachably attached to the housing of the sheet feeding device. When provided with a mounting detection device for detecting whether the sheet storage unit is in a mounted state attached to the housing or a non-mounted state pulled out from the housing. One or a plurality of the reference feeding processes are one or a plurality of the feeding processes executed in a situation where the lift mechanism first lifts the stacked sheets to the contact position after the detection result of the mounting detection device changes from the non-mounted state to the mounted state, satisfying the mounting condition and the number condition of the sheet feeding state determination method according to appended note 6 or appended note 7.

[0286] <Appended Note 9> The sheet feeding state determination method according to any one of appended notes 1 to 8, including that when the determination result of the deterioration state deviates from the allowable range, the processing device outputs an alarm through an information output device.

[0287] <Appended Note 10> A feeding mechanism comprising a feeding rotating body that contacts the upper surface of the top sheet in a loading sheet, a discharge rotating body positioned at a distance from the feeding rotating body, and a separating member positioned below the discharge rotating body and biased toward the discharge rotating body, wherein a feeding process is performed to feed each sheet from the loading sheet to a transport path by rotating the feeding rotating body and the discharge rotating body, and the accompanying sheets that are discharged along with each sheet are separated from each sheet by the separating member, A sheet detection device that detects each of the sheets at a detection position downstream of the sheet feeding direction relative to the feed rotating body and the separating member, A timing device that measures the elapsed time from the time when the feeding process for each of the sheets is started until the time when each of the sheets is detected by the sheet detection device, A sheet feeding device comprising a processing device that implements the sheet feeding state determination method described in any one of the above appendices 1 to 9.

[0288] <Note 11> The sheet feeding device described in Appendix 10 above, An image forming apparatus comprising: a printing device that forms an image on each sheet fed by the aforementioned sheet feeding device. [Explanation of symbols]

[0289] 1a: Lower enclosure 2: Sheet feeding device 3: Sheet conveying device 4: Printing device 4x: Image forming section 8: Control device 10: Image forming apparatus 20: Feeding mechanism 21: Lift mechanism 22: Pickup Roller 23: Feed Roller 24: Retard Roller 24a: Torque limiter 25: Feeding sheet detection device 26: Wearing detection device 30: Conveyor path 32: Conveyor Sheet Detection Device 90: Loading sheet 200: Sheet Cassette 200a: Cassette tip wall 211: Lift plate 211a: Rotary shaft 212: Push-up board 212a: Rotary shaft 213: End Cursor 214: Side cursor 230: Feed motor 241: Spring

Claims

1. A feeding mechanism comprising a feeding rotating body that contacts the upper surface of the top sheet in a loading sheet, a discharge rotating body positioned at a distance from the feeding rotating body, and a separating member positioned below the discharge rotating body and biased toward the discharge rotating body, wherein a feeding process is performed to feed each sheet from the loading sheet to a transport path by rotating the feeding rotating body and the discharge rotating body, and the accompanying sheets that are discharged along with each sheet are separated from each sheet by the separating member, A sheet detection device that detects each of the sheets at a detection position downstream of the sheet feeding direction relative to the feed rotating body and the separating member, A sheet feeding state determination method for determining the state of a sheet feeding device, comprising a timing device that measures the elapsed time from the time the feeding process for each sheet is started until the time each sheet is detected by the sheet detection device, The processing device derives a positional deviation amount, which represents the amount of deviation of the target sheet's position from its initial reference position at the start of the feeding process, based on the target measurement time measured by the timing device and a preset reference feeding time for the target sheet being fed by the feeding process. The processing apparatus counts the number of times the positional deviation exceeds a separation failure determination value corresponding to the path length from the initial reference position to the separation member, A method for determining the sheet feeding state, comprising the processing apparatus determining the deterioration state of the feeding mechanism based on the number of separation failures.

2. The processing apparatus records actual data of the excess positional deviation amount, which represents the amount by which the positional deviation amount exceeds the separation failure judgment value. The sheet feeding state determination method according to claim 1, wherein the processing apparatus determines the deterioration state of the feeding mechanism based on actual data of the number of separation failures and the amount of positional misalignment.

3. The processing apparatus counts the number of times the positional displacement exceeds the number of individual separation failures, each of which is a separation failure determination value. The sheet feeding state determination method according to claim 1 or claim 2, wherein the processing apparatus determines the deterioration state of the feeding mechanism based on the number of individual separation failures.

4. The processing apparatus counts the number of misalignment counts, which is the number of times the misalignment amount exceeds a misalignment determination value that is smaller than the separation failure determination value. The sheet feeding state determination method according to claim 1 or claim 2, wherein the processing apparatus determines the deterioration state of the feeding mechanism based on the frequency of the number of separation failures relative to the number of positional misalignments.

5. The processing device counts the number of feeding operations, which is the number of feeding operations. The sheet feeding state determination method according to claim 1 or 2, wherein the processing apparatus determines the deterioration state of the feeding mechanism based on the frequency of the number of separation failures relative to the number of feeding cycles.

6. When the sheet feeding device includes a lift mechanism that lifts the loaded sheets to a contact position where the uppermost surface of the top sheet in the loaded sheets contacts the feeding rotating body, The processing device derives the standard feeding time based on one or more standard feeding processes measured by the timing device when one or more standard feeding processes are performed that satisfy the count condition, which is one or more feeding processes performed a predetermined number of times after the lift mechanism lifts the loaded sheet to the contact position. The sheet feeding state determination method according to claim 1 or 2, further comprising the processing device performing a first position deviation deriving process that derives the position deviation amount according to the difference between the target measurement time and the reference feeding time.

7. If, before the target sheet is fed, one or more recent measurement times measured by the timing device for one or more consecutive sheets fed immediately before the feeding of the target sheet, and the target measurement time are not below the reference feeding time, the processing device executes the first position misalignment derivation process. The sheet feeding state determination method according to claim 6, further comprising: when the continuous positional misalignment state occurs, the processing device performing a second positional misalignment derivation process to derive the amount of positional misalignment corresponding to the difference between the shortest time among the most recent measurement time and the target measurement time and the reference feeding time.

8. The aforementioned sheet feeding device, A sheet storage unit that supports the lift mechanism, houses the loaded sheet, and is retractably mounted in the housing of the sheet feeding device, When the seat storage unit is provided with an installation detection device that detects whether it is in an installed state, mounted in the housing, or in an uninstalled state, pulled out from the housing, The sheet feeding state determination method according to claim 6, wherein the one or more reference feeding processes are performed when the lift mechanism first lifts the loaded sheet to the contact position after the detection result of the mounting detection device changes from the non-mounted state to the mounted state, satisfying the mounting condition and the number of times condition.

9. The sheet feeding state determination method according to claim 1 or 2, wherein the processing device outputs an alarm through an information output device when the determination result of the deterioration state falls outside the acceptable range.

10. A feeding mechanism comprising a feeding rotating body that contacts the upper surface of the top sheet in a loading sheet, a discharge rotating body positioned at a distance from the feeding rotating body, and a separating member positioned below the discharge rotating body and biased toward the discharge rotating body, wherein a feeding process is performed to feed each sheet from the loading sheet to a transport path by rotating the feeding rotating body and the discharge rotating body, and the accompanying sheets that are discharged along with each sheet are separated from each sheet by the separating member, A sheet detection device that detects each of the sheets at a detection position downstream of the sheet feeding direction relative to the feed rotating body and the separating member, A timing device that measures the elapsed time from the time when the feeding process for each of the sheets is started until the time when each of the sheets is detected by the sheet detection device, A sheet feeding device comprising a processing device that implements the sheet feeding state determination method according to claim 1 or claim 2.

11. A sheet feeding device according to claim 10, An image forming apparatus comprising: a printing device that forms an image on each sheet fed by the aforementioned sheet feeding device.

Images