JP7229748B2 - Paper feeder and image forming device - Google Patents

Description

The present invention relates to a paper feeder and an image forming apparatus such as a copying machine and a printer provided with the paper feeder. In particular, the present invention relates to life detection of a separation rotator which is provided in a paper feeder and separates and conveys recording materials.

2. Description of the Related Art Conventionally, image forming apparatuses such as copiers and printers are provided with a paper feed mechanism that separates and feeds recording materials stacked in a paper feed unit one by one. Various types of paper feeding mechanisms are employed. One of them is a separation transfer system using a separation rotary body. The separating and conveying method using a separating rotating body includes a retard separating method using a retard roller that is a type of separating rotating member and a separating roller method using a separating roller that is a type of separating rotating member without driving. There is

For a retard separation type paper feeding mechanism using a feed roller and a retard roller, a technique such as that disclosed in Japanese Patent Application Laid-Open No. 2002-100003 has been proposed. That is, when the number of rotations of the retard roller is equal to or less than a predetermined number of rotations, and the number of paper feeds continues for a predetermined number of times, it is determined that the life of the roller in the paper feed operation is approaching, and a message to that effect is displayed on the display device. . In addition, for a separation roller type paper feeding mechanism, a technique such as that disclosed in Japanese Patent Application Laid-Open No. 2002-200003 has been proposed. That is, only the feed roller is driven without driving the separation roller, and the rotating state of the separation roller when the separation roller is rotated by the feed roller is monitored by an encoder that outputs a signal composed of two-phase pulse signals. do. Then, the phase difference between the two-phase pulse signals of the monitored encoder is detected, and uneven wear of the separation roller is detected based on whether or not the phase difference is within a preset reference value range.

As the wear of the separation rotor such as the separation roller progresses, paper dust adheres to the recording material and the shape of the separation rotor is scraped off due to wear. As a result, the rotational speed of the separation rotor is in an unstable state in which fast and slow rotations coexist. After that, when the wear further progresses and the conveying performance of the separation rotor deteriorates, the rotational speed continuously decreases. That is, the life of the separation rotor can be determined by measuring the rotation speed of the separation rotor.

JP-A-11-035183 Japanese Patent No. 4176551

However, in the conventional example, no consideration is given to appropriate timing for detecting the rotation speed of the separation rotor. That is, when measuring the rotation speed of the separation rotor, it is desirable to detect the rotation state during a period when there are few disturbance factors and the rotation of the separation rotor is stable, in order to increase the detection accuracy of the rotation speed. Conversely, if the rotation speed is detected during a period in which the rotation of the separation rotor is not stable, there is a risk of erroneously detecting the end of the life of the separation rotor. For example, if detection is performed when the leading edge of the recording material enters the separation rotating body or when the trailing edge of the recording material leaves feeding means such as a pickup roller, the leading edge of the recording material enters or the trailing edge comes off. Recoil, etc., when it is pressed, affects the detection result of the separation rotating body.

Therefore, as an example of how to determine the period for detecting the rotation state of the separation rotor (hereinafter referred to as the detection period), there is the following method. That is, there is a method of setting the detection period by estimating the rotation period of the separation rotary member based on the timing at which the leading edge of the recording material reaches leading edge detection means provided in the conveying path of the recording material. However, when such a method is used, depending on the size of the recording material and the stop position of the recording material, the detection timing overlaps with the timing at which the separation rotator stops. may not be able to In addition, the electromagnetic clutch that transmits the driving force for conveying the recording material to each drive mechanism has a time until the electromagnetic clutch is connected (hereinafter referred to as connection time) and a time until it stops after releasing the connection (hereinafter referred to as , release time). Variations in the connection time and release time of the electromagnetic clutch affect the time to start conveying the recording material and the time to stop it. As a result, the detection period varies every time the recording material is conveyed, and there is a possibility that the rotational speed of the separation rotor cannot be detected and obtained during the originally assumed detection period. Therefore, it is important to appropriately determine the detection period of the separation rotating body in consideration of the factors described above.

SUMMARY OF THE INVENTION An object of the present invention is to appropriately set a period for detecting the rotational speed of a separation rotor.

In order to solve the above problems, the present invention has the following configurations.

(1) Feeding means for feeding the recording material at a contact position in contact with the recording material stacked on the stacking section, and a paper feed rotator for feeding the recording material fed by the feeding means. a separation nip portion is formed by coming into contact with the paper feeding rotating body, and when a plurality of recording materials are fed from the stacking portion, one sheet of the recording material is separated and conveyed downstream in the conveying direction. A separation rotator, a first detection means for detecting the rotation state of the separation rotator, and a connected state when the driving force of the drive means is transmitted to at least the paper supply rotator to cut off the transmission of the driving force. a transmission means that is in a released state at times; a judgment means for judging whether or not the separation rotator has reached the end of its service life based on the detection result of the first detection means; and control means for outputting a signal, wherein the determination by the determination means is made based on the timing at which the control means outputs the drive signal and the detection result of the first detection means. Determination means for determining the start timing is provided, and the determination means outputs a drive signal for setting the transmission means to the connected state at a predetermined timing for starting the determination, from the timing when the drive signal for setting the transmission means to the connection state is output. 1. A sheet feeding device, wherein the timing for starting the determination is determined by adding a first time up to the timing at which the first detection means detects that the separation rotator has started rotating.
(2) Feeding means for feeding the recording material at a contact position in contact with the recording material stacked on the stacking section, and a paper feeding rotator for feeding the recording material fed by the feeding means. a separation nip portion is formed by coming into contact with the paper feeding rotating body, and when a plurality of recording materials are fed from the stacking portion, one sheet of the recording material is separated and conveyed downstream in the conveying direction. A separation rotator, a first detection means for detecting the rotation state of the separation rotator, and a connected state when the driving force of the drive means is transmitted to at least the paper supply rotator to cut off the transmission of the driving force. a transmission means that is in a released state at times; a judgment means for judging whether or not the separation rotator has reached the end of its service life based on the detection result of the first detection means; and control means for outputting a signal, wherein the determination by the determination means is made based on the timing at which the control means outputs the drive signal and the detection result of the first detection means. Determination means for determining a start timing is provided, and the determination means determines that the separation rotator starts rotating by the first detection means from the timing of outputting a drive signal for bringing the transmission means into the connection state. It is detected by the first detection means that the separation rotor has stopped rotating from the first time until the timing at which it is detected and the timing at which the drive signal for setting the transmission means to the release state is output. and a timing to start the determination based on a second time until the timing of the paper feeding.
(3) Feeding means for feeding the recording material at a contact position in contact with the recording material stacked on the stacking section, and a paper feeding rotator for feeding the recording material fed by the feeding means. a separation nip portion is formed by coming into contact with the paper feeding rotating body, and when a plurality of recording materials are fed from the stacking portion, one sheet of the recording material is separated and conveyed downstream in the conveying direction. A separation rotator, a first detection means for detecting the rotation state of the separation rotator, and a connected state when the driving force of the drive means is transmitted to at least the paper supply rotator to cut off the transmission of the driving force. a transmission means that is in a released state at times; a judgment means for judging whether or not the separation rotator has reached the end of its service life based on the detection result of the first detection means; and control means for outputting a signal, wherein the determination by the determination means is made based on the timing at which the control means outputs the drive signal and the detection result of the first detection means. Determination means for determining a start timing, wherein the determination means stops rotation of the separation rotor by the first detection means from the timing of outputting the drive signal for bringing the transmission means into the release state. A sheet feeding device, wherein the timing for starting the determination is determined based on a second time until the timing at which the fact is detected.
(4) A recording medium comprising: a paper feeding device according to any one of (1) to (3); and an image forming unit that forms an image on a recording material fed from the paper feeding device. image forming device.

According to the present invention, it is possible to appropriately set the period for detecting the rotational speed of the separation rotor.

1 is a diagram showing the configuration of an image forming apparatus and a paper feeding option device of Embodiments 1 to 3; FIG. 4 is a diagram showing control blocks of the image forming apparatuses of Examples 1 to 3; FIG. 11 is a diagram showing a control block of the paper feed option device of the first to third embodiments; A diagram showing the operation of paper feed control in Examples 1 to 3. Timing chart of paper feed control in the first embodiment A diagram showing the configuration of the optional paper feed device according to the second embodiment. Timing chart of paper feed control in the second embodiment A diagram showing the configuration of the optional paper feeder according to the third embodiment. Timing chart of paper feed control of the third embodiment

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

[Image forming apparatus]
An outline of an electrophotographic image forming apparatus and a printing operation of the image forming apparatus according to the first embodiment will be described. FIG. 1 is a schematic diagram of an image forming apparatus 101 and a paper feed option device 201 detachable from the image forming apparatus 101. As shown in FIG. A cassette 102 , which is an example of a paper feed unit, is a storage unit for the recording material S and is detachable from the image forming apparatus 101 . While the cassette 102 is attached to the main body of the image forming apparatus 101 , a pickup roller 103 serving as a feeding means feeds the recording material S accommodated in the cassette 102 . The recording material S fed by the pickup roller 103 is conveyed to a nip portion formed by a feed roller 106 as a paper feeding rotating body and a retard roller 105 as an example of a separating rotating body. The feed roller 106 forms a nip portion together with the retard roller 105, and prevents a plurality of sheets (two or more sheets) of the recording material S from being fed to the downstream side in the transport direction from the nip portion. Only one recording material S conveyed reaches a top sensor 108 via a registration roller pair (hereinafter referred to as a registration roller pair) 107 .

Next, the recording material S is conveyed to the image forming section. The image forming section includes a photosensitive drum 109 , a transfer roller 110 , a charging roller 111 , a developing device 112 , a laser scanner 113 and a fixing device 114 . After being charged by the charging roller 111, the photosensitive drum 109 is irradiated with the laser beam L from the laser scanner 113 to form an electrostatic latent image on the surface. The electrostatic latent image formed on the photosensitive drum 109 is visualized as a toner image by supplying toner from the developing device 112 . The photosensitive drum 109 and the transfer roller 110 form a transfer nip portion, and the recording material S is conveyed to the transfer nip portion in synchronization with the rotation of the photosensitive drum 109 . The toner image formed on the photosensitive drum 109 is transferred to the recording material S by applying a voltage to the transfer roller 110 at the transfer nip portion. The recording material S onto which the unfixed toner image has been transferred is conveyed to the fixing device 114, where it is heated and pressurized. As a result, the unfixed toner image transferred onto the recording material S is fixed onto the recording material S. FIG. The recording material S on which the toner image is fixed is conveyed by the triple roller 116, the intermediate discharge roller 117, and the discharge roller 118, and is discharged to the discharge tray 121, completing a series of printing operations.

Further, when performing double-sided printing on the recording material S, the recording material S that has been printed on one side is not discharged to the discharge tray 121, and the trailing edge of the recording material S has passed through the triple roller 116. ) later, the triple roller 116, the intermediate discharge roller 117, and the discharge roller 118 are reversely rotated. As a result, the recording material S is conveyed to the double-sided conveying path 125 and further conveyed to the image forming section by the double-sided conveying rollers 122 . Further, in FIG. 1, a fixing discharge sensor 115 and a double-sided conveying sensor 123 are provided to determine whether the recording material S is conveyed normally. The control unit 150 will be described later.

[Feeding option device]
Next, an outline of the operation of the electrophotographic paper feed option device 201 of the first embodiment will be described. The option cassette 202 in FIG. 1 is a storage section (stacking section) for the recording material S, and is detachable from the paper feed option device 201 . With the option cassette 202 attached to the main body of the paper feed option device 201 , the option pickup roller 203 serving as a feeding means feeds the recording material S accommodated in the option cassette 202 . The recording material S fed by the option pickup roller 203 is fed to the downstream side in the conveying direction of the recording material S by the option feed roller 206 which is a paper feeding rotating body. The option feed roller 206 forms a nip portion with the option retard roller 205, which is a separation rotating body, and a plurality of sheets (two or more sheets) of the recording material S are both fed from the nip portion to the downstream side in the transport direction. to prevent The recording material S conveyed by one sheet reaches the optional conveying sensor 208 via the optional conveying roller pair 207 . Further, the recording material S is conveyed by the optional conveying roller pair 207 and reaches the top sensor 108 via the registration roller pair 107 of the image forming apparatus 101 . After that, the operation after the recording material S is conveyed to the image forming unit is the same as the printing operation of the image forming apparatus 101 . In addition, this paper feed option device 201 can be used by attaching a plurality of paper feed option devices to the image forming apparatus 101 . The option control section 250 will be described later. The above is a general description of the configuration and printing operation of the image forming apparatus 101 and the paper feed option device 201 .

[Control section]
Next, the configuration and functions of the control unit 150 provided in the image forming apparatus 101 will be described. FIG. 2 is a block diagram of the control unit 150 provided in the image forming apparatus 101 and the driving unit of the image forming apparatus 101. As shown in FIG. The control unit 150 has a measurement unit 151, a storage unit 152, a determination unit 153, and a drive control unit 155, and controls each drive mechanism. A motor 160 as a driving means is a driving source for driving the pair of registration rollers 107 and the electromagnetic clutch 170 . Furthermore, the electromagnetic clutch 170 transmits or cuts off the driving force of the motor 160 to the pickup roller 103, the feed roller 106, and the separation rotor. In the first embodiment, the retard roller 105 to which the driving force is transmitted in the direction to prevent the feeding of the recording material S is used as an example of the separation rotating member. However, it is also possible to use a roller to which drive is not transmitted, a so-called separation roller, as the separation rotor. Also driven are a top sensor 108 that detects the leading edge position of the recording material S conveyed via the pair of registration rollers 107 and notifies the control unit 150, and an encoder 104 that detects the rotation state of the retard roller 105 and notifies the measurement unit 151. It is a mechanism related to In Example 1, the encoder 104 uses, for example, a code wheel provided coaxially with the retard roller 105 . However, the configuration of the encoder 104 is not limited to this, and an optical rotary encoder, a magnetic rotary encoder, a photointerrupter, or the like can be used depending on the required accuracy and location.

Next, functions of the control unit 150 and the detection mechanism will be described. By controlling the motor 160 and the electromagnetic clutch 170, the drive control unit 155 can switch ON and OFF of the drive to each mechanism. The measurement unit 151 detects that the signal received from the encoder 104 rises when the retard roller 105 actually starts rotating at the timing when the drive control unit 155 outputs a signal for driving the electromagnetic clutch 170 (hereinafter referred to as an ON signal). Measure the time to The measurement unit 151 also measures the rotation state of the retard roller 105 detected by the encoder 104 and outputs the result to the storage unit 152 and the determination unit 153 . An example of information detected by the encoder 104 is the rotational speed of the retard roller 105 . In the first embodiment, the average value V1 of the rotation speed of the retard roller 105 during the period in which the retard roller 105 rotates stably is used as the rotation speed of the retard roller 105 output to the determination unit 153 . A method for setting the period during which the retard roller 105 rotates stably will be described later.

Based on the average value V1 calculated by the measuring unit 151, the determining unit 153 determines whether the life of the retard roller 105 is nearing its end. Note that the life of the separation rotor refers to the usage time of the separation rotor that is assumed in design, for example. If the rotation performance of the retard roller 105 to follow the recording material S deteriorates due to wear or the like, the rotation speed of the retard roller 105 per unit time decreases. can do. If the average value V1 is lower than the preset rotation speed, the determination unit 153 determines that the retard roller 105 has reached the end of its life, and notifies the result. Further, the determination unit 153 notifies the panel (not shown) of the image forming apparatus 101 and the user of information regarding the life of the retard roller 105 . The storage unit 152 has a function of storing the rotation speed of the retard roller 105 output from the measuring unit 151 described above, the time from when the electromagnetic clutch 170 is driven until the signal output from the encoder 104 rises, and the like. The information regarding the life of the separation rotator can be used to determine the life of the separation rotator, such as the usage time and total number of rotations of the separation rotator, the total number of recording materials S conveyed through the nip portion, and the like. Information.

The controller 150 provided in the image forming apparatus 101 has been described above. These configurations and functions can be similarly applied to the case where the paper feed option device 201 is provided with a control unit. A block diagram of FIG. 3 is an example of a configuration in which the option controller 250 is provided in the sheet feed option device 201 . In the example of FIG. 3, the motor 160 provided on the image forming apparatus 101 side is used as the drive source of the paper feeding option device 201 . However, it is also possible to provide the paper feed option device 201 with a motor as a drive source for the paper feed option device 201 .

[Option controller]
The option control unit 250 in FIG. 3 has an option measurement unit 251 , an option storage unit 252 , an option determination unit 253 , and an option drive control unit 255 , and controls each drive mechanism of the paper feed option device 201 . The motor 160 is a drive source that drives at least the paper feed clutch 270 and the transport clutch 280 . The paper feed clutch 270 transmits or interrupts the driving force of the motor 160 to the optional pickup roller 203 . On the other hand, the transport clutch 280, which is a transmission means, transmits or cuts off the driving force of the motor 160 to the option feed roller 206, the option transport roller pair 207, and the option retard roller 205, which is an example of a separation rotating body. The optional retard roller 205 is connected to the carrier clutch 280 via the torque limiter 209 . A separation roller to which drive is not transmitted can also be used as the separation rotating body, and the transport clutch 280 transmits the driving force of the motor 160 to at least the option feed roller 206 . The option conveying sensor 208 detects the position of the leading edge of the recording material S conveyed via the option conveying roller pair 207 and notifies the option control unit 250 of the detected position. The option encoder 204 , which is first detection means, detects the rotation state of the option retard roller 205 and notifies it to the option measurement unit 251 .

Functions of the option control unit 250 and the detection mechanism will be described. An option drive control unit 255, which is control means, receives commands from the control unit 150 and controls the paper feed clutch 270 and the transport clutch 280, thereby switching on and off the drive to each mechanism. The option measurement unit 251 measures the following times. That is, the time from when the option drive control unit 255 outputs an ON signal for driving the transport clutch 280 to when the signal received from the option encoder 204 rises after the option retard roller 205 actually starts rotating is measured. The option measurement unit 251 also measures the rotation state of the option retard roller 205 detected by the option encoder 204 and outputs the result to the option storage unit 252 and the option determination unit 253 . An option determination unit 253 serving as determination means determines whether the life of the option retard roller 205 is nearing the end of its life based on the data calculated by the option measurement unit 251, that is, the detection result of the option encoder 204. FIG. The mechanism of the option encoder 204, the information to be detected, and the data calculated by the option measurement unit 251 are the same as those of the encoder 104 and the measurement unit 151 of the image forming apparatus 101, so description thereof will be omitted. Also, the method of determining the service life of the option retard roller 205 by the option determination unit 253, the information stored in the option storage unit 252, and the like are the same as those of the determination unit 153 and the storage unit 152 of the image forming apparatus 101, so description thereof will be omitted.

[How to set the detection period T]
Next, details of a method for setting a period T (hereinafter referred to as a detection period T) for detecting the rotation speed of the separation rotor (optional retard roller 205) for performing paper feed control and life judgment of the separation rotor will be described with reference to FIG. , will be described with reference to FIG. In the description, the paper feed configuration of the paper feed option device 201 having the same configuration as the paper feed mechanism of the image forming apparatus 101 is used. FIG. 4 shows how the recording material S contained in the option cassette 202 is being fed and conveyed. The option cassette 202 accommodates a plurality of sheets of the recording material S. The recording material S on the uppermost surface of the plurality of recording materials S is the recording material S1, and the recording material S contained in contact with the recording material S1 is recorded. Material S2.

The horizontal axis of FIG. 5 indicates the elapsed time t. The vertical axis in FIG. 5A indicates ON (ON) and OFF (OFF) of the drive signal for the paper feed clutch 270 . The vertical axis in FIG. 5B indicates ON (ON) and OFF (OFF) of the drive signal for the transport clutch 280 . When these drive signals are ON, the paper feed clutch 270 or the transport clutch 280 are connected, and when they are OFF, the paper feed clutch 270 or the transport clutch 280 are released. The vertical axis of FIG. 5(c) indicates the state of the output signal of the optional transport sensor 208. FIG. The option control unit 250 detects “presence” of the recording material S when the output signal of the option conveyance sensor 208 is on (ON), and detects “absence” of the recording material S when it is off (OFF). That is, the option control unit 250 determines that the leading edge of the recording material S has reached the option transport sensor 208 (or the option transport roller pair 207) when the output signal of the option transport sensor 208 rises from OFF to ON. The option control unit 250 determines that the trailing edge of the recording material S has passed (or has come off) the option conveying sensor 208 (or the option conveying roller pair 207) when the output signal of the option conveying sensor 208 falls from ON to OFF. to decide. The vertical axis of FIG. 5D indicates the rotation speed V of the option retard roller 205, and indicates a waveform obtained by converting the signal output from the option encoder 204 (option encoder signal) into the rotation speed. V1 indicates the average value of the rotation speed V of the option retard roller 205, which will be described later, and is hereinafter referred to as the average value V1.

(Time Ta)
4A shows a cross-sectional view of the option cassette 202 at the timing of feeding the recording material S1, which is the top of the recording materials S accommodated in the option cassette 202. FIG. The recording material S in the option cassette 202 is positioned by a regulation plate (not shown) or the like in the option cassette 202. When the recording material S1 is fed, the leading edge of the recording material S1 is positioned at Ps in FIG. (hereinafter referred to as position Ps). The timing of FIG. 4(a) is time Ta in FIG. When paper feed control is started, the drive control unit 155 rotates the motor 160 . The option drive control unit 255, which has received an instruction from the control unit 150 at time t0, outputs a drive signal (ON signal) for the paper feed clutch 270 to turn on the paper feed clutch 270, and applies the driving force of the motor 160 to the option pickup roller. 203. The option drive control unit 255 that has received the instruction from the control unit 150 outputs a drive signal (ON signal) for the carrier clutch 280 at time Ta to turn on the carrier clutch 280 . Then, the driving force of the motor 160 is transmitted to the option feed roller 206 , the option retard roller 205 and the option transport roller pair 207 . As a result, the option pickup roller 203, the option feed roller 206, the option retard roller 205, and the option conveying roller pair 207 start rotating to feed and convey the recording material S1 in the sheet feeding direction indicated by the arrow in FIG. do. A position Pp in FIG. 4A is a position (contact position) where the optional pickup roller 203 contacts the recording material S, that is, a position where the recording material S is nipped. Hereinafter, the position Pp will also be referred to as the paper feed nip portion Pp. A position Pfr is the position of the separation nip formed by the optional feed roller 206 and the optional retard roller 205 . Hereinafter, the position Pfr will also be referred to as a separation nip portion Pfr.

The optional retard roller 205 is provided with a torque limiter 209, and the drive is transmitted in the direction to prevent the sheet S from being fed. This torque limiter 209 is located between the transport clutch 280 and the optional retard roller 205 and has a constant rotational load. The option feed roller 206 starts rotating in the direction of feeding the recording material S (counterclockwise direction in FIG. 4). Here, when the recording material S does not exist in the separation nip portion, the force that the optional retard roller 205 receives due to friction with the optional feed roller 206 exceeds the rotational load of the torque limiter 209 provided on the optional retard roller 205 . Therefore, the optional retard roller 205 rotates in the direction of feeding the recording material S (clockwise direction in FIG. 4). Even when only one recording material S is conveyed to the separation nip portion Pfr, the force received by the optional retard roller 205 due to friction with one recording material S is set to exceed the rotational load of the torque limiter 209. . Therefore, the option retard roller 205 is driven to rotate in the direction of feeding the recording material S (clockwise direction in FIG. 4). On the other hand, when two or more recording materials are conveyed to the separation nip portion Pfr, the rotation of the torque limiter 209 is greater than the force received by the optional retard roller 205 due to the frictional force between the recording materials S conveyed in piles. The load is set to win. For this reason, the optional retard roller 205 stops because the force received by friction and the rotational load are balanced, or the rotational load of the torque limiter 209 overcomes the force received by friction and hinders paper feeding (counterclockwise in FIG. 4). direction). At time Ta, the drive signal for the transport clutch 280 rises from OFF to ON.

(Time Tb)
FIG. 4B shows a cross-sectional view of the option cassette 202 at the timing when the leading edge of the recording material S1 reaches the option transport roller pair 207 and the option transport sensor 208, which is the second detection means. The timing of FIG. 4(b) is the time Tb of FIG. The conveying speed of the recording material S1 may fluctuate due to vibration caused by the recording material S1 coming into contact with the optional conveying roller pair 207 and conveying force from the optional conveying roller pair 207 being transmitted to the recording material S1 (Fig. 5 (d )). Further, when there is a recording material S that has been conveyed before the recording material S1, the recording material S1 may be temporarily stopped when the leading edge of the recording material S1 reaches the optional conveyance sensor 208 in order to adjust the timing of image formation. As a result, the rotation speed of the optional retard roller 205 that rotates following the recording material S1 may also fluctuate. At time Tb, the output signal of the option transport sensor 208 rises from OFF to ON.

(Time Tc)
FIG. 4C shows a cross-sectional view of the option cassette 202 at the timing when the trailing edge of the recording material S1 reaches the paper feed nip portion Pp of the option pickup roller 203. FIG. The timing of FIG. 4(c) is the time Tc of FIG. In the paper feed option device 201, in order to prevent the recording material S2, which is the succeeding recording material fed after the recording material S1 (hereinafter referred to as subsequent paper), from being pushed into the separation nip portion and causing a paper jam, The following controls are performed. That is, the paper feed clutch 270 is switched from on to off before the trailing edge of the recording material S1 passes through the paper feed nip portion Pp. As a result, transmission of driving force from the motor 160 to the option pickup roller 203 is cut off, and the rotation of the option pickup roller 203 is stopped. Also in the first embodiment, the drive signal for the paper feed clutch 270 falls from ON to OFF at time t3 before time Tc in FIG. Even if the rotation of the option pickup roller 203 stops, the recording material S1 is transported in the paper feed direction by the option transport roller pair 207 . Therefore, the option feed roller 206 and the option retard roller 205 are also driven to rotate following the recording material S1. At time Tc when the trailing edge of the recording material S1 passes the paper feed nip portion Pp, the frictional force applied to the recording material S1 by the optional pickup roller 203 disappears. Therefore, the recording material S1 may vibrate, and the rotation speed of the optional retard roller 205 may fluctuate (FIG. 5(d)). Even after the trailing edge of the recording material S1 passes through the paper feeding nip portion Pp, the recording material S1 is conveyed downstream in the paper feeding direction by the optional conveying roller pair 207 .

(Time Td)
FIG. 4D shows a cross-sectional view of the option cassette 202 at the timing when the trailing edge of the recording material S1 has passed through the separation nip portion Pfr. The timing of FIG. 4(d) is the time Td of FIG. After the trailing edge of the recording material S1 passes through the separation nip portion Pfr, the recording material S1 is transported downstream in the paper feeding direction by the optional transport roller pair 207 . When the recording material S1 passes the option conveying sensor 208 as it is and the leading edge of the recording material S1 reaches the pair of registration rollers 107 and the top sensor 108, the drive signal for the conveying clutch 280 changes from on to off at time t4, and the motor 160 cut off the transmission of the driving force of As a result, the option feed roller 206, option conveying roller pair 207, and option retard roller 205 stop rotating. The recording material S<b>1 is conveyed on the conveying path of the image forming apparatus 101 while being pulled by the pair of registration rollers 107 . The time from time t4 when the drive signal (OFF signal) for the transport clutch 280 is output to time Td when the trailing edge of the recording material S1 passes through the separation nip portion Pfr is Tla.

(Setting of detection period T)
By the way, the life of the optional retard roller 205 is determined based on the result of detecting the average value V1 of the rotation speed of the optional retard roller 205 as described above. Therefore, the detection of the service life is performed by avoiding the timing when the rotation speed is likely to fluctuate due to disturbance, such as the moment when the leading edge of the recording material S1 enters the nip portion of each roller or the moment when the trailing edge of the recording material S1 passes each roller. It is desirable to provide a period T. For example, the detection period T can be set to the period from time t2 to time t3, avoiding time Tb and time Tc in FIG. The detection period T is set in advance to avoid the time Tb and the time Tc, and is stored in the option storage unit 252 or the like. Time t2′ is the time when the preset detection period, particularly the preset detection period, starts. The preset detection period is, for example, set as a period from time t2' to when a predetermined time elapses with reference to the timing (time Ta) at which the driving signal for the transport clutch 280 rises from OFF to ON. and

However, there is a case where the assumed detection period (which is also the time t2' described above) and the actual detection period T (hereinafter referred to as the actual detection period T) deviate from each other. For example, after the option drive control unit 255 outputs a drive signal for the transport clutch 280 (time Ta), until the drive force of the motor 160 is transmitted and the option retard roller 205 actually starts rotating (time t1), A slight delay Tlb occurs. The delay Tlb is hereinafter referred to as a time lag Tlb. The time lag Tlb, which is the first time, is influenced by the time from when the transport clutch 280 receives the drive signal (ON signal) to the completion of the connection and the time until the gear parts mesh with each other. This time lag Tlb leads to a delay in the timing of starting the transportation of the recording material S1 (hereinafter referred to as the transportation start timing). In other words, if the time until the transport clutch 280 is connected becomes longer, the transmission of the driving force to the option feed roller 206 and the option retard roller 205 will be delayed, and the transport of the recording material S1 will be delayed (hereinafter referred to as transport delay). If the time lag Tlb is always constant, it is possible to set the detection period T for judging the life in consideration of it. not. In particular, this time lag Tlb varies more as the rotation speed of the transport clutch 280 decreases, and affects the transport characteristics of the recording material S1.

In Example 1, the option control unit 250 calculates the time from time Ta to time t1, that is, time lag Tlb. Here, time Ta is the time when the option drive control unit 255 outputs the drive signal (ON signal) for the transport clutch 280 . Time t1 is the time when the rotation speed of the option retard roller 205, that is, the output signal of the option encoder 204 rises. Accordingly, the option control unit 250 determines the detection period T for life determination. The option control unit 250 functions as a determination unit that determines the timing at which the detection period T starts. In this method, since the detection period T is set after detecting the rise (time t1) of the output signal of the optional encoder 204, the rotational speed is detected when the optional retard roller 205 is reliably rotating. be able to.

Also, the distance from the paper feed nip portion Pp to the separation nip portion Pfr and the distance from the separation nip portion Pfr to the nip portion of the option conveying roller pair 207 are known in advance. Therefore, the timing (time Tb) at which the leading edge of the recording material S1 enters the nip portion of the option conveying roller pair 207 and the timing (time Tc) at which the trailing edge of the recording material S leaves the paper feed nip portion Pp should be avoided. can be done. In other words, the time lag Tlb is used to correct the time t2′ at which the detection period T starts, and the detection period T is set in consideration of the stable rotation of the optional retard roller 205 and the conveyance variation of the recording material S. becomes possible. In the first embodiment, the time "t2'+Tlb" obtained by adding the time lag Tlb to the time t2' for the time from the time Ta when the driving signal is output to the time t2' when the detection period T starts. , is time t2, which is the start timing of the corrected detection period T. FIG. That is, in the first embodiment, the predetermined time t2' at which the detection period T starts is corrected by the time lag Tlb to obtain the time t2=t2'+Tlb, and the detection period T is a predetermined time from the time t2. .

As described above, in the first embodiment, the detection period T for judging the service life of the optional retard roller 205 is set so that the rotation of the separation rotator is stabilized and the correction of the conveyance variation at the start of conveyance is taken into consideration. In the first embodiment, the paper feed option device 201 is used for explanation, but this can also be applied to the setting method of the detection period for judging the life of the retard roller 105 of the image forming apparatus 101 .

As described above, according to the first embodiment, it is possible to appropriately set the period for detecting the rotational speed of the separation rotor.

[Feeding option device]
In the second embodiment, a method of setting the detection period for judging the life of the separation rotator will be described, taking into account the correction of conveyance variations at the start and stop of conveyance. The optional paper feed device 201 can be used by stacking several stages. FIG. 6 shows an example of a cross-sectional view when the sheet feeding option devices 201 are stacked in three stages, for example. Here, for the three paper feed option devices 201, the uppermost stage is denoted by (i), the lowermost stage is denoted by (iii), and the middle stage is denoted by (ii). Further, in the second embodiment, regarding the recording material S conveyed toward the image forming unit, the recording material S conveyed first to the image forming unit (hereinafter also referred to as preceding paper) is the recording material S1, the recording material S1 The subsequent recording material S (hereinafter referred to as subsequent paper) conveyed to the image forming section is referred to as recording material S2. The image forming apparatus 101 is attached to the upper stage of the paper feeding option apparatus 201, but since the image forming apparatus 101 is explained in the first embodiment, illustration thereof is omitted in the first embodiment. Also, in the second embodiment, the image forming apparatus 101 includes a motor 160 that serves as a drive source for all paper feeding mechanisms provided in the optional paper feeding device 201 . This is an example of the configuration, and the optional paper feed device 201 may be provided with a motor that serves as a drive source for all the paper feed mechanisms provided in the optional paper feed device 201 .

When the optional paper feed devices 201 are stacked in several stages as in the second embodiment, the recording material S can be fed and conveyed alternately from different optional paper feed devices 201 . FIG. 6 is one example. In FIG. 6, the recording material S1 is the recording material S that is fed first from the uppermost paper feed option device 201(i). Also, the recording material S2 is the recording material S2 fed from the bottom sheet feeding option device 201(iii). When the recording material S1 fed from the paper feed option device 201(i) is conveyed first to the image forming apparatus 101, the recording material S2 conveyed later should not collide with the recording material S1 in the conveying path (collision It is necessary to secure a certain interval or more for transportation. Depending on the image forming conditions, it may be necessary to temporarily stop the recording material S2 in order to secure an interval with the recording material S1, and then start conveying it again (hereinafter referred to as re-conveying). When the recording material S2 is temporarily stopped, the detection period T is affected not only by the variation in the initial feeding of the recording material S2 but also by the variation when the recording material S2 is stopped and re-transported. need to be considered.

[Paper Feed Conveyance Control in Embodiment 2]
FIG. 7 shows a time chart of each signal and sensor in the second embodiment. The horizontal axis of FIG. 7 indicates the elapsed time t. The vertical axis in FIG. 7A indicates the drive signal (ON signal or OFF signal) of the paper feed clutch 270(iii) of the paper feed option device 201(iii) at the bottom. The vertical axis in FIG. 7B indicates the drive signal (ON signal or OFF signal) of the transport clutch 280(iii) of the paper feed option device 201(iii) at the bottom. The vertical axis in FIG. 7(c) indicates the output signal (ON signal or OFF signal) of the option transport sensor 208(iii) of the sheet feed option device 201(iii) at the bottom. The vertical axis of FIG. 7(d) indicates the output signal (ON signal or OFF signal) of the option transport sensor 208(i) of the paper feed option device 201(i) at the top. The ON signal of the option conveying sensor 208(i) indicates that the recording material S1 and the recording material S2 are detected. The vertical axis in FIG. 7(e) indicates the rotational speed (option encoder signal) of the optional retard roller 205(iii) of the optional paper feed device 201(iii) at the bottom. FIG. 7(e) also shows rotational speeds Vmin and Vmax, which will be described later. In addition, the same symbols are attached to the times having the same meanings as in FIG. 5(d) in each time attached to the horizontal axis. Note that time t4′ in FIG. 7(e) corresponds to time t4 in FIG. 5(d), and time t4 in Example 2 will be described later.

In the second embodiment, the service life of the optional retard roller 205(iii) is determined using the minimum value Vmin and the maximum value Vmax of the rotation speed of the option retard roller 205(iii) during the detection period T for service life determination. When the rotational speed Vmin and the rotational speed Vmax are outside the predetermined speed range (outside the range), the use of the optional retard roller 205 (iii) progresses and uneven wear occurs, which increases the variation in the rotational speed and shortens the service life. determined to have reached When the rotational speed Vmin and the rotational speed Vmax are within the predetermined speed range, the optional retard roller 205 (iii) maintains a nearly circular shape, so the rotational speed is stable and it is determined that the service life has not been reached. be. In addition, in the configuration of the second embodiment, the service life of the optional retard roller 205(iii) may be determined based on the average value V1 of the rotation speed V. FIG. Also, the determination of the life of the separation rotor based on the rotation speeds Vmin and Vmax may be applied to other embodiments.

When the conveyance of the recording material S2 is started, the following time lag Tlb1 occurs. That is, from time Ta when the option drive control unit 255(iii) outputs the drive signal (ON signal) for the transport clutch 280(iii) to time t1 when the option retard roller 205(iii) actually starts rotating, there is only a short time. , a time lag Tlb1 occurs. The time lag Tlb1 is influenced by the time from when the transport clutch 280(iii) receives the drive signal (ON signal) to the completion of the connection and the time until the gear parts mesh with each other. The time lag Tlb1 similarly exists when the conveyance of the recording material S2 is restarted. Let Tlb2 be the time lag from time ts' to time t1' that occurs when the conveyance of the recording material S2 is restarted. Further, when the conveyance of the recording material S2 is temporarily stopped at a predetermined timing, the following time lag Tla occurs. That is, the time lag from time t4 when the option drive control unit 255(iii) outputs a stop signal (OFF signal) for the transport clutch 280(iii) to time ts when the option retard roller 205(iii) completely stops rotating. Tla occurs. These two types of time lags Tlb1, Tlb2, and Tla affect the conveying performance of the recording material S2. Therefore, the detection period T for determining the life of the optional retard roller 205(iii) must be set in consideration of the time lags Tlab1, Tlb2, and Tla. If these factors are not taken into consideration, the period in which the optional retard roller 205(iii) is not stably rotating overlaps with the life judgment detection period T, and there is a risk that correct life judgment cannot be made.

[Setting of detection period T]
Therefore, a method for setting the detection period T for determining the life of the optional retard roller 205 (iii) considering the time lags Tlb1, Tlb2, and Tla between when the recording material S2 starts to be conveyed and when the conveying is stopped will be described in detail with reference to FIG. I do. After starting the transport of the recording material S1, the option drive control unit 255 (iii) outputs a drive signal for the transport clutch 280 (iii) that starts feeding the recording material S2 at time Ta, and the option pickup roller 203 (iii) drive the The option drive control unit 255(iii) also outputs a drive signal for the transport clutch 280(iii) that starts transporting the recording material S2 at time Ta. Then, the driving force of the motor 160 is transmitted to the option feed roller 206(iii), the option retard roller 205(iii) and the option transport roller pair 207(iii), and the option retard roller 205(iii) is rotated at time t1. begin. At this time, the option measurement unit 251(iii) measures the time lag Tlb1. Specifically, the option measurement unit 251(iii) measures the time from time Ta to time t1. Time Ta is the time when the option drive control unit 255(iii) outputs the drive signal for the transport clutch 280(iii). Time t1 is the time when the signal from the option encoder 204(iii) rises, indicating that the option retard roller 205(iii) has actually started rotating.

After a certain period of time (predetermined timing) has elapsed since the leading edge of the recording material S1 reached the option transport sensor 208(i), which is the second detection means, the option drive control unit 255(iii) performs the following control. I do. That is, at time t4, the option drive control unit 255(iii) outputs a stop signal for the paper feed clutch 270(iii) and the transport clutch 280(iii) so that the recording material S2 does not collide with the recording material S1. At this time, the option measurement unit 251(iii) measures the time lag Tla. Specifically, the option measurement unit 251(iii) measures the time from time t4 to time ts. Time t4 is the time when the option drive control unit 255(iii) outputs a stop signal for the carrier clutch 280(iii). Time ts is the time when the signal of the option encoder 204(iii) indicating that the rotation of the option retard roller 205(iii) has stopped falls.

The recording material S1 is conveyed, and the trailing edge of the recording material S1 passes the optional conveyance sensor 208(i) at time ts' (FIG. 7(d)). At time ts′, the option drive control unit 255(iii) outputs a drive signal for the feed clutch 270(iii) that starts (resumes) feeding of the recording material S2 and a transport clutch 280(iii) that starts transporting the recording material S2. ) is output again. As a result, the conveyance of the recording material S2 is resumed. The option measurement unit 251(iii) measures the time lag Tlb2. Specifically, the option measurement unit 251(iii) measures the time from time ts' to time t1'. Time ts' is the time when the option drive control unit 255(iii) outputs the drive signal for the carrier clutch 280(iii). Time t1' is the time when the signal of option encoder 204(iii) rises indicating that the rotation of option retard roller 205(iii) has rotated.

Then, the option measuring unit 251 (iii) uses the first time lags Tlb1 and Tlb2 and the second time lag Tla to determine the detection period T for life determination of the optional retard roller 205 (iii). decide. For example, the option measurement unit 251 calculates the final detection period T for determining the life span by including the difference value obtained by subtracting the value of the time lag Tla from the total value of the time lags Tlb1 and Tlb2 in the presupposed detection period. do. Note that the detection period T is based on the time Ta at which the drive signal for the transport clutch 280(iii) that transports the recording material S2 is first output.

Here, the time lags Tlb1 and Tlb2 are delays in the start of conveying the recording material S2. When the recording material S2 is to be stopped, the recording material S2 stops upstream in the conveying direction from the position instructed by the option drive control unit 255 (iii). means to Conversely, the time lag Tla is a delay in stopping the conveying of the recording material S, and means that the recording material S2 stops downstream in the conveying direction from the position instructed by the option drive control unit 255(iii).

Therefore, when the value of the above-described arithmetic expression "(Tlb1+Tlb2)-Tla" is a positive value, the delay in starting transportation is greater than the delay in stopping transportation ((Tlb1+Tlb2)>Tla). This means that the recording material S2 has to be transported extra by temporarily stopping the transport and restarting the transport, that is, the detection period T has shifted later in time than previously assumed. On the other hand, when the value of the above-described arithmetic expression "(Tlb1+Tlb2)-Tla" is a negative value, the delay in stopping transportation is greater than the delay in starting transportation ((Tlb1+Tlb2)<Tla). This means that the recording material S2 has to be transported with a delay due to the temporary stop of transport and the restart of transport, that is, the detection period T has shifted earlier than expected.

The option control unit 250(iii) corrects the time t2, which is the start time of the detection period T, using the time lags Tlb1, Tlb2, and Tla obtained by measuring these deviations. As a result, the detection period T for judging the life of the optional retard roller 205(iii) is set, excluding the deviation of the conveyance start timing and the conveyance stop timing of the recording material S2, and the life judgment of the optional retard roller 205(iii) is appropriately performed. can be done.

In the second embodiment, the time from the time Ta at which the drive signal is output to the start time t2' of the presumed detection period T is corrected as follows. That is, the time obtained by adding "(Tlb1+Tlb2)-Tla" to the time t2', which is the detection start timing provided in advance, becomes the time t2, which is the start timing of the corrected detection period T. Specifically, when the value of the above-described arithmetic expression “(Tlb1+Tlb2)−Tla” is a positive value, the positive value is added to time t2′, and the time t2 at which the detection period T starts is time t2′. set later than When the value of the above-described arithmetic expression “(Tlb1+Tlb2)−Tla” is a negative value, the negative value is added to (subtracted from) time t2′, and the time t2 at which the detection period T starts is time t2 ' is set earlier.

As described above, in the second embodiment, the method of setting the detection period T for judging the life of the separation rotating member in consideration of the correction of the transfer variation at the start and stop of the transfer has been described. In the second embodiment, the paper feed option device 201 is used for explanation, but this can also be applied to the setting method of the detection period T for judging the life of the retard roller 105 of the image forming apparatus 101 . Also, in the second embodiment, the description has been made with the optional paper feed devices 201(i) and 201(iii) attached to the uppermost and lowermost stages, but the optional paper feed devices 201 in other stages are also applicable. is possible.

As described above, according to the second embodiment, it is possible to appropriately set the period for detecting the rotational speed of the separation rotor.

[Feeding option device]
In the third embodiment, a method of setting the detection period for judging the life of the separation rotating member in consideration of the correction of the conveyance variation when the conveyance of the recording material S is stopped will be described. FIG. 8 shows an example of a cross-sectional view of a case in which three optional paper feed devices 201 are stacked and the recording material S is conveyed continuously from the optional paper feed device 201(iii) at the bottom. The numbering is the same as in the second embodiment. In Example 3, the recording material S is a long paper whose length in the conveying direction is longer than that of plain paper (recording material having a predetermined length). The recording material S2 is the recording material S conveyed after the recording material S1. The image forming apparatus 101 is attached to the upper stage of the paper feed option device 201, but illustration of the image forming apparatus 101 is omitted in FIG. Also, in the third embodiment, the image forming apparatus 101 includes a motor 160 that serves as a drive source for all paper feed mechanisms provided in the paper feed option device 201 . The image forming apparatus 101 and the paper feed option device 201 are bodies capable of transporting the recording material S at a higher speed than the transport speed of plain paper. This is an example of the configuration, and the paper feed option device 201 can also be provided with a motor serving as a drive source for the paper feed mechanism provided in the paper feed option device 201 .

[Paper Feed Conveyance Control in Embodiment 3]
FIG. 9 shows a time chart of each signal and sensor of the paper feed option device 201(iii) in the third embodiment. The horizontal axis of FIG. 9 indicates the elapsed time t. The vertical axis in FIG. 9A indicates the drive signal (ON signal or OFF signal) of the paper feed clutch 270(iii) of the paper feed option device 201(iii) at the bottom. The vertical axis in FIG. 9B indicates the drive signal (ON signal or OFF signal) of the transport clutch 280(iii) of the paper feed option device 201(iii) at the bottom. The vertical axis in FIG. 9(c) indicates the output signal (ON signal or OFF signal) of the option transport sensor 208(iii) of the sheet feed option device 201(iii) at the bottom. The vertical axis in FIG. 9D indicates the rotation speed (option encoder signal) of the option retard roller 205(iii) of the sheet feed option device 201(iii) at the bottom. The average value V1 of the rotational speed V is also shown in FIG.9(d). In addition, the same symbols are attached to the times having the same meaning as in FIG. 7(e) in each time attached to the horizontal axis.

After the recording material S1 is transported, at time Ta, the option drive control unit 255 (iii) outputs a drive signal for the paper feed clutch 270 (iii) for feeding the recording material S2 and a drive signal for the transport clutch 280 (iii). do. Then, the driving force of the motor 160 is transmitted to the option pickup roller 203(iii), the option feed roller 206(iii), the option retard roller 205(iii), and the option transport roller pair 207(iii). As a result, the optional retard roller 205(iii) starts rotating at time t1. At this time, a time lag Tlb1 occurs. The time lag Tlb1 is the time from time Ta to time t1. Time Ta is the time when the option drive control unit 255(iii) outputs the drive signal for the transport clutch 280(iii). Time t1 is the time when the signal of the option encoder 204(iii) rises, indicating that the option retard roller 205(iii) has actually started rotating.

The time lag Tlb at the start of conveyance also occurs when the conveyance of the recording material S2 is resumed at time ts' after the conveyance of the recording material S2 is temporarily stopped at time ts in order to secure a distance from the recording material S1. . The time lag that occurs at this time is assumed to be Tlb2. The main factors of the time lags Tlb1 and Tlb2 are the time until the transport clutch 280 (iii) is engaged and the time until the gears are engaged. The time lags Tlb1 and Tlb2 become shorter as the rotation speed of the transport clutch 280 and the rotation speed of the gears increase. When the conveying speed of the recording material S is high as in the third embodiment, the time lags Tlb1 and Tlb2 at the start of conveying are shorter than when the conveying speed of the recording material S is slow. can be ignored as it has little effect on

On the other hand, in order to temporarily stop the recording material S2, the option drive control unit 255(iii) outputs a stop signal for the paper feed clutch 270(iii) and a stop signal for the transport clutch 280(iii) at time t4. Then, the drive power of motor 160 to optional pickup roller 203(iii), optional feed roller 206(iii), optional transport roller pair 207(iii), and optional retard roller 205(iii) is disconnected. As a result, the optional retard roller 205(iii) stops rotating at time ts. However, even if the stop signal for the transport clutch 280(iii) is output, the transport clutch 280(iii) and the optional retard roller 205(iii) do not stop immediately, but stop after continuing to rotate for a while due to inertia. This is the time lag Tla1. The time lag Tla1, which is the second time, is a delay in stopping the conveyance of the recording material S2, and the recording material S2 stops downstream in the conveyance direction from the position instructed by the option drive control unit 255(iii). Further, the time lag Tla1 becomes longer as the rotational speed of the optional retard roller 205(iii) increases.

Therefore, in the third embodiment, the option measurement unit 251(iii) measures the time from time t4 when the stop signal of the transport clutch 280(iii) is output to time ts when the option retard roller 205(iii) completely stops rotating. to measure That is, the option measurement unit 251(iii) measures the time lag Tla1, which is the time until the signal of the option encoder 204(iii) falls. The option control unit 250(iii) determines the time t2, which is the start timing of the detection period T, based on the time lag Tla1. As a result, it is possible to set the detection period T for determining the service life of the optional retard roller 205(iii) that is not affected by the conveying characteristics of the recording material S2.

Incidentally, in FIG. 7 of the second embodiment, the paper feed clutch 270(iii) is turned off at time t3 before the transport clutch 280(iii) is turned off at time t4'. On the other hand, in the third embodiment, at time t4', the feed clutch 270(iii) is also turned off together with the conveyance clutch 280(iii). This is because the recording material S of Example 3 is long paper. By turning on the paper feed clutch 270 as much as possible while the recording material S2 is being conveyed, the back tension on the recording material S2 by the optional pickup roller 203 is reduced so as not to affect the conveying characteristics. Further, when the recording material S subsequent to the recording material S2 is conveyed, the time lag Tla2 measured by the option measurement unit 251 (iii) is used to appropriately set the interval with the recording material S to be conveyed later. It is possible to secure Note that the time lag Tla2 is the time from time t4' to time Td.

In the third embodiment, the option control unit 250 (iii) subtracts the time lag Tla1 from the time t2′, which is the start timing of the detection period T provided in advance, from the time Ta at which the drive signal is output (t2=t2′− Tla1). As described above, in Example 3, the time lags Tlb1 and Tlb2 can be ignored. This value becomes time t2, which is the start timing of the corrected detection period T. FIG.

As described above, in the third embodiment, the method of setting the detection period for judging the life of the separation rotator in consideration of the conveyance variation when the conveyance of the recording material is stopped has been described. In the third embodiment, the paper feed option device 201 is used for explanation, but this can also be applied to the setting method of the detection period for judging the life of the retard roller 105 of the image forming apparatus 101 . Also, in the third embodiment, the paper feed option device 201(iii) attached to the bottom stage has been described as an example, but it is also applicable to the paper feed option device 201 in another stage.

As described above, according to the third embodiment, it is possible to appropriately set the period for detecting the rotational speed of the separation rotor.

203 Option pickup roller 204 Option encoder 205 Option retard roller 206 Option feed roller 250 Option control unit 253 Option determination unit 255 Option drive control unit 280 Carrying clutch

Claims (11)

feeding means for feeding the recording material at a contact position in contact with the recording material stacked on the stacking unit;
a paper feeding rotator for feeding the recording material fed by the feeding means;
A separation nip portion is formed by coming into contact with the paper feeding rotating body, and when a plurality of recording materials are fed from the stacking portion, one sheet of recording material is separated and conveyed downstream in the conveying direction. a rotating body;
a first detection means for detecting the rotation state of the separation rotor;
a transmission means that is in a connected state when transmitting the driving force of the driving means to at least the sheet feeding rotating body and is in a disengaged state when the transmission of the driving force is interrupted;
determination means for determining whether or not the separation rotator has reached the end of its service life based on the detection result of the first detection means;
a control means for outputting a drive signal to control the transmission means;
A sheet feeding device comprising
determining means for determining the timing for starting the determination by the determination means based on the timing at which the control means outputs the drive signal and the detection result of the first detection means ;
The determination means rotates the separation rotating body by the first detection means from the timing of outputting a drive signal for bringing the transmission means into the connected state at a predetermined timing for starting the determination. and determining the timing for starting the determination by adding a first time up to the timing when the start of the determination is detected. feeding means for feeding the recording material at a contact position in contact with the recording material stacked on the stacking unit;
a paper feeding rotator for feeding the recording material fed by the feeding means;
A separation nip portion is formed by coming into contact with the paper feeding rotating body, and when a plurality of recording materials are fed from the stacking portion, one sheet of recording material is separated and conveyed downstream in the conveying direction. a rotating body;
a first detection means for detecting the rotation state of the separation rotor;
a transmission means that is in a connected state when transmitting the driving force of the driving means to at least the sheet feeding rotating body and is in a disengaged state when the transmission of the driving force is interrupted;
determination means for determining whether or not the separation rotator has reached the end of its service life based on the detection result of the first detection means;
a control means for outputting a drive signal to control the transmission means;
A sheet feeding device comprising
determining means for determining the timing for starting the determination by the determination means based on the timing at which the control means outputs the drive signal and the detection result of the first detection means;
The determining means defines a first time from the timing at which a drive signal for bringing the transmission means into the connected state is output to the timing at which the first detecting means detects that the separation rotating body has started to rotate. and a second time from the timing at which the drive signal for setting the transmission means to the released state is output to the timing at which the first detection means detects that the separation rotor has stopped rotating; A paper feeder, wherein a timing for starting the judgment is determined based on the above. The determining means determines the timing for starting the judgment by adding a value obtained by subtracting the second time from the first time to a predetermined timing for starting the judgment. 3. The sheet feeding device according to claim 2 , characterized by: 4. The sheet feeding device according to claim 1 , wherein the first time becomes longer as the rotation speed of the transmission means becomes slower . feeding means for feeding the recording material at a contact position in contact with the recording material stacked on the stacking unit;
a paper feeding rotator for feeding the recording material fed by the feeding means;
A separation nip portion is formed by coming into contact with the paper feeding rotating body, and when a plurality of recording materials are fed from the stacking portion, one sheet of recording material is separated and conveyed downstream in the conveying direction. a rotating body;
a first detection means for detecting the rotation state of the separation rotor;
a transmission means that is in a connected state when transmitting the driving force of the driving means to at least the sheet feeding rotating body and is in a disengaged state when the transmission of the driving force is interrupted;
determination means for determining whether or not the separation rotator has reached the end of its service life based on the detection result of the first detection means;
a control means for outputting a drive signal to control the transmission means;
A sheet feeding device comprising
determining means for determining the timing for starting the determination by the determination means based on the timing at which the control means outputs the drive signal and the detection result of the first detection means;
The determining means defines a second time from the timing at which the drive signal for bringing the transmission means into the released state is output to the timing at which the first detecting means detects that the separation rotor has stopped rotating. A sheet feeding device, wherein the timing for starting the determination is determined based on 6. The supply according to claim 5 , wherein the determining means determines the timing for starting the determination by subtracting the second time from a predetermined timing for starting the determination. paper device. 7. The sheet feeding device according to claim 5 , wherein the second time increases as the rotation speed of the separation rotor increases. A second detection means provided downstream in the conveying direction from the separation nip,
The predetermined timing is the timing after the timing at which the leading edge of the preceding sheet conveyed ahead of the recording material being conveyed in the separation nip portion is detected by the second detecting means. and the timing is set in advance so that the trailing edge of the preceding sheet comes out of the contact position before the timing. 1. Paper feeding device according to item 1. 2. The judging means judges that the separation rotator has reached the end of its life based on the average value of the rotation speed of the separation rotator detected by the first detection means. The sheet feeding device according to any one of claims 8 to 8. The judging means judges that the separation rotator has reached the end of its life based on the maximum value and the minimum value of the rotational speed of the separation rotator detected by the first detection means. The sheet feeding device according to any one of claims 1 to 8 . a sheet feeding device according to any one of claims 1 to 10 ;
an image forming unit that forms an image on a recording material fed from the paper feeding device;
An image forming apparatus comprising:

Images