JP7005333B2 - Feeding device - Google Patents

Description

The present invention relates to an image forming apparatus that controls the feeding of recording materials in a feeding device used in a copying machine, a printer, or the like.

Conventionally, an image forming apparatus such as a copying machine or a printer is provided with a paper feeding mechanism that separates and feeds recording materials loaded on a paper feeding unit one by one. Various types of paper feed mechanisms are adopted, and one of them is a retard separation method using a separation roller. In the retard separation type paper feeding mechanism, a method has been devised in which the life of the separation roller is determined when the rotation speed of the separation roller is continuously equal to or less than a predetermined value for a predetermined number of times. (See, for example, Patent Document 1). Further, only the feed roller is driven without driving the separation roller, and the rotation speed of the separation roller when the separation roller is rotated by the rotation of the feed roller is monitored by the encoder. When the phase difference of the monitored encoder signal is out of the preset reference value range, a method of notifying the uneven wear of the separation roller has been devised (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 11-035183 Japanese Patent No. 4176551

As the separation roller wears, the rotation speed of the separation roller becomes unstable with a mixture of high speed and slow speed. After that, when the wear progresses further and the transfer performance of the separation roller deteriorates, the rotation speed continues. descend. That is, the unstable state before the rotation speed of the separation roller continuously decreases is a sign that the separation roller reaches the end of its life. According to the conventional method for determining the life of the separation roller, it can be determined that the life of the separation roller is when the rotation speed of the separation roller continuously falls below a predetermined value. However, it is difficult to detect a sign that the separation roller described above has reached the end of its life. Further, as the usage time elapses, the diameter of the separation roller becomes smaller due to wear, and the rotation speed of the separation roller increases. After that, as the separation roller wears further, the followability with the paper deteriorates, and the rotation speed of the separation roller gradually decreases while repeating minute slips. Therefore, variations in the diameter of the separation roller and the coefficient of friction of the surface during production, and changes in the rotation speed due to wear affect the detection accuracy.

Further, according to another conventional example, it is possible to determine the uneven wear of the separation roller. However, a mechanism for independently switching between driving and non-driving of the feed roller and the separation roller is required. Further, the rotation of the separation roller when one sheet of paper is conveyed by the separation nip portion changes depending on the paper type of the conveyed paper. In general, even with the same separation roller, the lower the coefficient of friction of the paper, the lower the followability of the separation roller to the paper, and the more likely it is that transfer defects will occur. In another conventional example, since the rotation speed of the separation roller is monitored by the frictional force of the feed roller, it is difficult to consider the influence on the paper transport performance.

The present invention has been made under such circumstances, and an object of the present invention is to accurately determine the life state of the separation roller.

In order to solve the above-mentioned problems, the present invention includes the following configurations.

(1) A feeding rotary body that feeds a plurality of recording materials mounted on the mounting unit one by one, and feeds the first recording material at the highest level of the above-mentioned mounting unit. Following the passage of the rear end of the first recording material, a feeding rotary body for feeding a second recording material lower than the first recording material in a partially overlapped manner with the first recording material, and the above-mentioned A transport rotating body that transports the recording material fed by the feed rotating body, and a separated rotating body that forms a nip portion with the transport rotating body, and the first recording material is fed to the nip portion. In that case, the first recording material is rotated in a predetermined direction, and when the first recording material and the second recording material overlap and are fed to the nip portion, the first recording material is used. A separated rotating body that stops rotation or rotates in a direction opposite to the predetermined direction in order to separate the recording material 1 and the second recording material, and outputs a signal according to the rotation state of the separated rotating body. Based on the output means to be output and the rotation speed of the separated rotating body represented by the signal from the output means, the feeding operation of the recording material by the feeding rotating body is controlled, and the tip of the second recording material is controlled. In a feeding device having a control means for controlling so as to stop when the first recording material reaches the nip portion, the control means is said to be in a state where the first recording material is fed to the nip portion. The life of the separated rotating body is based on the variation in the average value of the rotational speeds of the separated rotating body represented by the signal from the output means in the predetermined period during which the separated rotating body is rotated in the predetermined direction. A feeding device characterized by determining.
(2) A feeding rotary body that feeds a plurality of recording materials mounted on the mounting portion one by one, and feeds the first recording material at the highest level of the above-mentioned mounting portion. Following the passage of the rear end of the first recording material, a feeding rotary body for feeding a second recording material lower than the first recording material in a partially overlapped manner with the first recording material, and the above-mentioned A transport rotating body that transports the recording material fed by the feed rotating body, and a separated rotating body that forms a nip portion with the transport rotating body, and the first recording material is fed to the nip portion. In that case, the first recording material is rotated in a predetermined direction, and when the first recording material and the second recording material overlap and are fed to the nip portion, the first recording material is used. A separated rotating body that stops rotation or rotates in a direction opposite to the predetermined direction in order to separate the recording material 1 and the second recording material, and outputs a signal according to the rotation state of the separated rotating body. The second recording material is controlled by controlling the feeding operation of the recording material by the feeding rotating body based on the rotating speed of the separated rotating body represented by the output means to be output and the signal output from the output means. In a feeding device having a control means for controlling so that the tip of the head reaches the nip portion, the control means stops the rotation of the separated rotating body and drives the feeding rotating body. A feeding device, characterized in that the life of the separated rotating body is determined based on the rotational speed of the separated rotating body represented by a signal output from the output means after is turned off.

According to the present invention, the life state of the separation roller can be accurately determined.

Configuration diagram of the image forming apparatus of Examples 1 and 2. Control block diagram of the image forming apparatus of Examples 1 and 2. Control block diagram of the image forming apparatus of Examples 1 and 2. The figure explaining the operation of the paper feed control of Example 1. Timing chart when the paper feed control of Example 1 is executed A graph showing the rotation of the separation roller in the total number of paper feeds P1 to P3 of the first embodiment. A graph showing the relationship between the total number of sheets of paper fed and the rotation speed of the separation roller of the first embodiment. A flowchart showing the life determination process of the separation roller of the first embodiment. A flowchart showing the life determination process of the separation roller of the first embodiment. The figure explaining the operation of the paper feed control of Example 2. Timing chart when the paper feed control of the second embodiment is executed. A flowchart showing the life determination process of the separation roller of the second embodiment. A flowchart showing the life determination process of the separation roller of the second embodiment.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings by way of examples.

<Explanation of the configuration of the image forming apparatus>
In the first embodiment, an electrophotographic laser beam printer 101 (hereinafter referred to as a printer 101) is shown as an image forming apparatus (feeding apparatus). FIG. 1 is a schematic configuration diagram of the printer 101. The cassette 102 is an accommodating portion for accommodating the paper S which is a recording material, and is removable from the main body of the printer 101. The cassette 102 is also referred to as a mounting portion on which the paper S is mounted. The rear end control plate 126 provided on the cassette 102 regulates the rear end of the paper S housed in the cassette 102. Here, the rear end of the paper S means the end on the upstream side in the feeding direction of the paper S. The rear end control plate 126 is movable in the feeding direction, and is placed in a regular position according to the size (length in the feeding direction) of the paper S, so that the paper S is set in an appropriate position. ..

With the cassette 102 mounted on the main body of the printer 101, the pickup roller 103 (hereinafter referred to as the pick roller 103), which is a feeding rotating body, feeds the paper S housed in the cassette 102 (feeding). )do. The paper S fed by the pick roller 103 is further fed downstream by the feed roller 106, which is a transport rotating body, in the transport direction of the paper S. Then, the paper S reaches the top sensor 108 via the registration roller pair 107 (hereinafter, referred to as a registration roller pair 107). The separation roller 105, which is a separation rotating body, forms a separation nip portion with the feed roller 106, and prevents a plurality of sheets (two or more sheets) of paper S from being fed to the downstream side of the separation nip portion. The operation of the separation roller 105 will be described in detail later. As a result, of the paper S accommodated in the cassette 102, only the paper S located at the highest position in the direction orthogonal to the bottom surface of the cassette 102 is fed to the register roller pair 107.

The paper S detected by the top sensor 108, which is a detection means, is then conveyed to the image forming unit. The image forming unit includes a photosensitive drum 109, a charging roller 111, a laser scanner 113, a developing device 112, a transfer roller 110, and a fixing device 114. After the photosensitive drum 109 is uniformly charged by the charging roller 111, the laser scanner 113 irradiates the photosensitive drum 109 with the laser beam L to form an electrostatic latent image on the surface. The electrostatic latent image thus formed 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 paper 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 paper S at the transfer nip portion. In order to transfer the toner image, a voltage having the opposite polarity to that of the toner image is applied to the transfer roller 110. The paper S on which the toner image is transferred is conveyed to the fixing device 114, where it is heated and pressurized. As a result, the unfixed toner image transferred to the paper S is fixed to the paper S. The paper 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. This completes a series of printing operations.

Further, when printing is performed on both sides of the paper S, the paper S that has been printed on one side is not discharged to the ejection tray 121, and after the rear end of the paper S has passed through the triple roller 116, the triple roller 116, The intermediate discharge roller 117 and the discharge roller 118 are rotated in the reverse direction. The paper S is conveyed to the double-sided transfer path 125, and is further conveyed to the image forming unit by the double-sided transfer roller 122. This makes it possible to print on both sides of the paper S.

Further, in FIG. 1, the fixing / discharging sensor 115 and the double-sided transport sensor 123 are provided to determine whether the paper S is normally fed. Further, the paper presence / absence sensor 104 is provided to detect whether or not the paper S is contained in the cassette 102. The printer 101 is provided with an operation panel 211 (hereinafter referred to as a panel 211) which is a display unit, and displays various information to the user. The printer 101 includes a control unit 200, and the control unit 200 will be described in detail below.

<Control unit>
FIG. 2 is a block diagram of the control unit 200 of the printer 101. The control unit 200 is composed of an engine control unit 201 and a video controller 202, and the two communicate with each other to realize the above-mentioned print operation. For example, when a print instruction is notified from an external device (not shown) such as a personal computer, the video controller 202 analyzes the image data, and the engine control unit 201 controls each mechanism of the printer 101 according to the analysis result. do. The engine control unit 201 includes a measurement unit 206, a determination unit 207, an output unit 208, a storage unit 209, and a drive control unit 210. The measuring unit 206 measures the elapsed time from the start of feeding the paper S by the pick roller 103. Further, the measuring unit 206 measures the rotation speed of the separation roller 105 based on the rotation state of the separation roller 105 detected by the encoder 203. The measurement unit 206 outputs the measured time information and the measured rotation speed information of the separation roller 105 to the determination unit 207.

The determination unit 207 determines the life of the separation roller 105 based on the rotation speed of the separation roller 105 measured by the measurement unit 206. The determination unit 207 outputs the determination result to the output unit 208. The output unit 208 notifies the user of the information regarding the life of the separation roller 105 output from the determination unit 207 via the panel 211 or an external device. The storage unit 209 stores the print request information notified from the video controller 202, the time measured by the measurement unit 206 in the past, and the like. The drive control unit 210 controls the start and stop of the paper feed mechanism according to the detection results of various sensors described later.

Further, the engine control unit 201 is connected to an encoder 203, which is an output means for outputting a signal according to the rotation state of the separation roller 105, and a top sensor 108. The drive control unit 210 controls the drive of the pick roller 103 using the detection results of these sensors. Here, as the encoder 203, for example, a chord wheel provided coaxially with the separation roller 105 is used. In addition, an optical rotary encoder, a magnetic rotary encoder, a photo interrupter, or the like can be used depending on the required accuracy and the placement location. Further, a panel 211 for the output unit 208 to output information is connected to the engine control unit 201.

FIG. 3 is a block diagram showing a detailed paper feeding mechanism. In FIG. 3, the motor 300 is a drive source for driving the pick roller 103, the feed roller 106, the separation roller 105, and the registration roller pair 107. The electromagnetic clutch 301 transmits or disconnects the driving force of the motor 300 to the pick roller 103, the feed roller 106, and the separation roller 105. The drive control unit 210 can switch on / off the drive to each member by controlling the motor 300 and the electromagnetic clutch 301. As will be described in detail later, the drive is transmitted to the pick roller 103 and the feed roller 106 in the direction of feeding the paper S, whereas the drive is transmitted to the separation roller 105 in the direction of hindering the feeding of the paper S. To. Further, a torque limiter 302 is provided between the electromagnetic clutch 301 and the separation roller 105. In order to detect the rotational state of the separation roller 105, the printer 101 is provided with the encoder 203 described above, and the information detected by the encoder 203 is input to the measurement unit 206. Here, as the information detected by the encoder 203, for example, the rotation speed of the separation roller 105, that is, the rotation speed of the separation roller 105 per unit time can be mentioned. In this embodiment, a so-called retard roller in which the drive is transmitted in a direction that hinders the feeding of the paper S as the separation roller 105 will be described as an example, but a roller in which the drive is not transmitted can also be applied.

<Explanation of paper feed control>
Next, the paper feed control of the printer 101 of the first embodiment will be described with reference to FIGS. 4 and 5. In FIG. 4, the shape of the transport path from the separation nip portion to the top sensor 108 is drawn so as to be different from that in FIG. 1, but this is for ease of explanation and is a diagram in another embodiment. The same shall apply to the drawings corresponding to 4. FIG. 4A shows a cross-sectional view of the cassette 102 at the timing of feeding the uppermost paper S1 housed in the cassette 102. When the paper feed control is started, the pick roller 103, the feed roller 106, and the separation roller 105 rotate, respectively, and the paper S1 is fed in the right direction (paper feed direction) in FIG. 4A. Here, the start of paper feed control means that the drive control unit 210 rotates the motor 300, further turns on the electromagnetic clutch 301, and transmits the driving force of the motor 300 to the pick roller 103, the feed roller 106, and the separation roller 105. Show to let.

In the graph of FIG. 5, the horizontal axis is the elapsed time t, the vertical axis is the state in which the drive of the pick roller 103 is on or off (ON / OFF), and (ii) is the signal waveform (on) of the top sensor 108. Or off), (iii) indicates the rotation speed V of the separation roller 105. The rotation speed Va1 will be described later. The timing Ta in FIG. 5 corresponds to the state shown in FIG. 4 (a). At the timing Ta, the drive of the pick roller 103 is switched from off to on, and then the separation roller 105 starts rotating. In FIG. 4A, the position Ps is the tip position of the paper S positioned by the rear end regulation plate 126. Here, the tip of the paper S refers to the end on the downstream side in the paper feeding direction of the paper S. The position Pp is a position where the pick roller 103 comes into contact with the paper S (nip the paper). The position Pfr is the position of the separation nip formed by the feed roller 106 and the separation roller 105.

The separation roller 105 is provided with a torque limiter 302 (described in FIG. 3) while the drive is transmitted in a direction (counterclockwise direction in FIG. 4A) that hinders the feeding of the paper S. Here, when the feed roller 106 starts rotating in the direction of feeding the paper S (counterclockwise direction of FIG. 4A), the separation roller 105 operates as follows by the torque limiter 302. First, when the paper S does not exist in the separation nip portion, the force received by the separation roller 105 due to friction with the feed roller 106 is set to exceed the rotational load of the torque limiter 302. Therefore, the separation roller 105 rotates in the direction in which the paper S is fed (clockwise in FIG. 4A). When one sheet of paper S is conveyed to the separation nip portion, the force received by the separation roller 105 due to friction with the one sheet of paper S is set to exceed the rotational load of the torque limiter 302. Therefore, the separation roller 105 is driven to rotate in the direction in which the paper S is fed, which is a predetermined direction. On the other hand, the rotational load of the torque limiter 302 is set to be superior to the conveying force of the sheets S when two or more sheets of the sheets S are conveyed to the separation nip portion. Therefore, the separation roller 105 stops in a direction in which the transfer force and the rotational load compete with each other, or the rotational load of the torque limiter 302 wins and prevents the paper feed in the direction opposite to the predetermined direction. do.

Next, FIG. 4B shows a cross-sectional view of the cassette 102 at the timing when the tip of the paper S1 reaches the register roller pair 107 and the top sensor 108. The timing Tb in the graph of FIG. 5 corresponds to the state shown in FIG. 4 (b). At the timing Tb, after the tip of the paper S1 comes into contact with the register roller pair 107, the paper S1 is conveyed by the register roller pair 107. At this time, the transport speed of the paper S1 may fluctuate due to the vibration in contact with the register roller pair 107 or the transfer force transmitted from the register roller pair 107 to the paper S1. Therefore, the rotation of the separation roller 105 driven by the paper S1 may also fluctuate as shown in the timing Tb of the graph of FIG. 5 (iii).

Next, FIG. 4C shows a cross-sectional view of the cassette 102 at the timing when the rear end (upstream side in the paper feeding direction) of the paper S1 reaches the position Pp of the nip portion of the pick roller 103. In the printer 101, the following control is performed in order to prevent the paper S2 from being pushed into the separation nip portion and causing a paper jam. That is, the drive of the pick roller 103 is switched from on to off at the timing t2 before the paper S1 reaches the position Pp of the nip portion of the pick roller 103. Here, switching the drive of the pick roller 103 from on to off means that the drive control unit 210 continues the rotation of the motor 300, while switching the electromagnetic clutch 301 from on to off to shut off the driving force of the motor 300. Show that. The timing t1 will be described later.

At this time, the drive of the feed roller 106, which is driven by the same drive source as the pick roller 103, is also turned off. However, since the paper S1 is conveyed in the paper feeding direction by the register roller pair 107, the feed roller 106 and the separation roller 105 are also driven and rotated following the paper S1. The timing Tc in FIG. 5 corresponds to the state shown in FIG. 4 (c). At the timing t2, the drive of the pick roller 103 is switched from on to off, but the separation roller 105 follows the paper S1 conveyed by the registration roller pair 107 and continues the driven rotation. Further, when the paper S1 passes through the position Pp of the nip portion of the pick roller 103, the frictional force applied to the paper S1 by the pick roller 103 disappears, so that the paper S1 vibrates and the graph of FIG. 5 (iii) is taken. The rotation of the separation roller 105 may fluctuate as described above.

Next, FIG. 4D shows a cross-sectional view of the cassette 102 at the timing when the rear end of the paper S1 passes through the position Pfr of the separation nip portion of the feed roller 106 and the separation roller 105. The timing Td in the graph of FIG. 5 corresponds to the state shown in FIG. 4 (d). Since the paper S1 has passed the position Pfr of the separation nip portion, the rotation of the feed roller 106 and the separation roller 105 has stopped. The paper S1 is conveyed to the downstream side in the paper feeding direction by the register roller pair 107. Further, when the rear end of the paper S1 passes through the top sensor 108, the signal of the top sensor 108 changes from on to off.

<Detection of life of separation roller>
Next, the transfer performance of the separation roller 105 is deteriorated due to wear or the like, and the change in the rotation speed of the separation roller 105 due to the decrease in the transfer performance will be described with reference to FIGS. 6 and 7. 6 (A) (a), 6 (B) (a), and 6 (C) (a) (i) to (iii) are the same graphs as FIGS. 5 (i) to (iii). Is. These drawings show the pick roller 103 and the top sensor corresponding to the total number of sheets P1 to P3 of the separation roller 105 described later in FIG. 7 when one sheet of paper S is fed according to the paper feed control shown in FIG. The ON or OFF state of 108 and the rotation speed of the separation roller 105 are shown. Here, the average value of the rotation speeds of the separation rollers 105 during the period from the preset timing t1 to the timing t2 is set to Va1. Then, since the average value Va1 between the timing t1 and the timing t2 can be obtained every time one sheet of paper S is fed, one data can be obtained every time one sheet of paper S is fed.

Here, the period for obtaining the average value Va1 of the rotation speed of the separation roller 105 is set while avoiding the timing in which the rotation of the separation roller 105 is likely to fluctuate, such as the timing Tb and the timing Tc described above. In the first embodiment, after the tip of the fed paper S rushes into the register roller pair 107, the separation roller 105 is driven to rotate following the paper S conveyed in the paper feed direction by the register roller pair 107. A period for obtaining the average value Va1 is set in. The preset timing t1 is the start timing of the period for obtaining the average value Va1, and the average value Va1 is set so as to avoid the timing when the rotation of the separation roller 105 is likely to fluctuate. Here, the time T1 is from the tip of the paper S reaching the top sensor 108 to the timing t1, and the time T2 is from the tip of the paper S reaching the top sensor 108 to the timing t2 (see FIG. 5).

In the graph of FIG. 7, the horizontal axis shows the total number of sheets to be fed, and the vertical axis shows the average value Va1 of the rotation speed of the separation roller 105. The rotation speed of the separation roller 105 gradually increases up to a predetermined number of sheets to be fed because the diameter of the separation roller 105 becomes smaller due to wear as the total number of sheets to be fed increases. .. FIG. 6A is a graph showing the rotation of the separation roller 105 in the total number of sheets to be fed P1 in FIG. 7. As shown in FIGS. 6A and 6A, the rotation speed of the separation roller 105 during driven rotation by the paper S in the total number of sheets to be fed P1 is relatively stable as in the case of a new separation roller 105. The average value Va1 of the rotation speed of the separation roller 105 is faster than that of the separation roller 105 when the separation roller 105 is new because the diameter of the separation roller 105 is reduced due to wear. FIGS. 6A and 6B show variations in the average value Va1 of the rotation speeds of the separation rollers 105 when 10 sheets of paper S are fed. The horizontal axis of FIGS. 6A and 6B shows the number of sheets to be fed, and the vertical axis shows the average value Va1 of the rotation speed of the separation roller 105. Here, when 10 sheets of paper S are fed, 10 pieces of data can be acquired as the average value Va1 of the rotation speed of the separation roller 105. The maximum value of the 10 average values Va1 is Va1_max, and the minimum value is Va1_min. Then, the difference between the maximum value Va1_max and the minimum value Va1_min of the average value Va1 of the separation roller 105 can be considered as the variation of the average value Va1 of the rotation speed of the separation roller 105. As shown in FIGS. 6A and 6A, the rotation speed of the separation roller 105 during the transfer of the paper S is stable at the time of the total number of sheets to be fed P1. Therefore, the variation in the average value Va1 of the rotation speeds of the separation rollers 105 in the predetermined period from the timing t1 to the timing t2 (the period of T2-T1) is small as in the case of a new separation roller 105.

FIG. 6B is a graph showing the rotation of the separation roller 105 in the total number of sheets to be fed P2 in FIG. 7. When the total number of sheets to be fed increases from P1 to P2, the separation roller 105 is further worn, and the average value Va1 of the rotation speeds of the separation rollers 105 becomes even faster than the total number of sheets to be fed P1. On the other hand, the frictional force with respect to the paper S is reduced due to factors that change the surface condition of the separation roller 105, such as wear of the rollers and adhesion of paper dust generated from the paper S. As a result, the rotation speed of the separation roller 105 cannot follow the paper S being conveyed in the paper feeding direction and rotate in a driven manner. Then, as shown in FIGS. 6B and 6A, the rotation speed is disturbed due to a slight slip of the separation roller 105 with respect to the paper S. Due to the disturbance of the rotation speed of the separation roller 105 due to this minute slip, the variation of the average value Va1 of the rotation speed of the separation roller 105, that is, the difference between the maximum value Va1_max and the minimum value Va1_min becomes larger than that of the total number of sheets to be fed P2. ..

6 (B) and 6 (b) are the same graphs as in FIGS. 6 (A) and 6 (b). As shown in FIGS. 6B and 6B, the variation in the average value Va1 of the separation roller 105 is larger than that when the total number of sheets to be fed is from zero to P1. When the total number of sheets to be fed is P2, the life state of the separation roller 105 is a state before the life, which is not a level at which transfer defects frequently occur due to deterioration of transfer performance. The state of the separation roller 105 as when the total number of sheets to be fed is P2 is defined as the life state Low level.

FIG. 6C is a graph showing the rotation of the separation roller 105 in the total number of sheets to be fed P3 in FIG. 7. When the total number of sheets to be fed changes from P2 to P3, the separation roller 105 is further worn and paper dust is adhered to the separation roller 105, and the frictional force of the separation roller 105 with respect to the paper S is significantly reduced, resulting in deterioration of the transport performance. Then, the separation roller 105 cannot be correctly driven and rotated with respect to the paper S. Then, as shown in FIGS. 6C and 6A, the rotation speed is greatly reduced or disturbed during the transportation of the paper S. In some cases, the rotation of the separation roller 105 exceeds the force received by the rotational load of the torque limiter 302 due to friction with the paper S, and may rotate in a direction that hinders stopping or feeding.

On the other hand, the average value Va1 of the rotation speed of the separation roller 105 is smaller than that when the diameter of the separation roller 105 is the total number of paper feeds P2. As a result, the rotation speed of the separation roller 105 may be faster, or it may be slower than when the separation roller 105 is new due to the influence of the decrease in the frictional force of the separation roller 105. At this time, as shown in FIGS. 6C and 6B, the variation in the average value Va1 of the rotation speeds of the separation rollers 105 is larger than that when the number of sheets to be fed is up to P2. 6 (C) and 6 (b) are the same graphs as in FIGS. 6 (A) and 6 (b). At this time, the life state of the separation roller 105 is a state in which the separation roller 105 has reached the end of its life, in which transfer defects frequently occur due to deterioration of transfer performance. The state of the separation roller 105 is defined as the life state Out level.

Therefore, the life state of the separation roller 105 can be determined by observing the variation in the average value Va1 of the rotation speed of the separation roller 105. Further, by observing the variation of the separation roller 105, it is possible to accurately detect the sign (life state Low level) that the separation roller 105 reaches the end of its life. This is because the life state of the separation roller 105 is the Low level shown in FIG. 6B, and the diameter of the separation roller 105 becomes smaller, so that the rotation speed of the separation roller 105 becomes faster than that of a new one. The same applies even if it is.

In addition, compared to the method of determining the life of the separation roller 105 based on whether the rotation speed of the separation roller 105 is lower than the preset threshold value, the method of determining based on the variation in the rotation speed of the separation roller 105 is based on the environment and The influence of variations in parts can be reduced. Even if the average rotation speed of the separation roller 105 differs due to the environment such as temperature and humidity and variations in parts, the average rotation speed of the separation roller 105 can be measured by observing the magnitude of the variation that actually indicates the stability of the followability of the separation roller 105 to the paper S. The effect of different rotation speeds can be minimized.

Further, the friction coefficient and the weight of the surface of the paper differ depending on the paper type of the paper S, and the behavior of the rotation speed of the separation roller 105 changes. In order to take this effect into consideration, the rotation of the separation roller 105 is monitored during the period in which the separation roller 105 is driven by friction with the paper S, not during the period in which the separation roller 105 is rotated by the feed roller 106. As a result, the life state of the separation roller 105 can be determined more accurately in consideration of the influence of the paper type on the transport performance.

Comparing the state in which the separation roller 105 and the feed roller 106 are in contact with each other and the state in which one sheet of paper is conveyed between the separation roller 105 and the feed roller 106, the latter causes the separation roller 105 to slip. It's easy to do. Therefore, the method of this embodiment is compared with the method of determining the life of the separation roller 105 from the rotation speed of the separation roller 105 during the period in which the separation roller 105 and the feed roller 106 are in contact with each other and the separation roller 105 is rotating. It is possible to detect a sign that the separation roller 105 reaches the end of its life earlier.

Further, in the method of determining the life of the separation roller 105 from the rotation speed of the separation roller 105 during the period in which the separation roller 105 and the feed roller 106 are in contact with each other and the separation roller 105 is rotating, the separation roller 105 reaches the end of its life at an early stage. It is not possible to detect the sign that it will reach, and if paper with a low coefficient of friction is conveyed, transfer defects may occur. According to this embodiment, since the detection is performed in the state where the paper is actually conveyed, whether the paper having a low coefficient of friction or the paper having a high coefficient of friction is conveyed, the transfer is defective in the future. It is possible to detect a sign that the separation roller 105 reaches the end of its life at an early stage so that

<Judgment processing of life status>
The method of determining the life state of the separation roller 105 in the first embodiment will be described with reference to the flowcharts of FIGS. 8 and 9. The control based on the flowcharts of FIGS. 8 and 9 is executed based on the program stored in the storage unit 209 such as the ROM by the engine control unit 201 mounted on the control unit 200.

First, it will be described from FIG. In step 101 (hereinafter referred to as S) 101, the engine control unit 201 sends a paper feed start instruction to the drive control unit 210 to start the paper feed operation. Further, the engine control unit 201 starts measuring the paper feed time by the measurement unit 206. In S102, the engine control unit 201 determines whether or not the tip of the paper S is detected by the top sensor 108. The engine control unit 201 determines that the tip of the paper S has been detected in response to the signal output from the top sensor 108 changing from off to on. If the engine control unit 201 determines in S102 that the tip of the paper S has been detected by the top sensor 108, the process proceeds to S103. If the engine control unit 201 determines in S102 that the tip of the paper S has not been detected by the top sensor 108, the process proceeds to S110.

In S103, the engine control unit 201 starts measuring the elapsed time from the timing when the paper S reaches the top sensor 108 by the measurement unit 206. In S104, the engine control unit 201 determines whether or not the elapsed time from the arrival of the tip of the paper S on the top sensor 108, which is measured by the measurement unit 206, has passed the time T1. When the engine control unit 201 determines in S104 that the time T1 has not elapsed, the process returns to S104, and the measurement unit 206 continues to measure the elapsed time since the tip of the paper S reaches the top sensor 108. .. When the engine control unit 201 determines in S104 that the time T1 has elapsed, the engine control unit 201 advances the process to S105.

In S105, the engine control unit 201 starts measuring the rotation speed of the separation roller 105 based on the rotation state of the separation roller 105 detected by the encoder 203 by the measurement unit 206. In S106, the engine control unit 201 determines whether or not the elapsed time from the arrival of the tip of the paper S on the top sensor 108 of S103, which is being measured by the measurement unit 206, has passed the time T2. When the engine control unit 201 determines in S106 that the time T2 has not elapsed, the process returns to S106, and the measurement unit 206 continues to measure the elapsed time since the tip of the paper S reaches the top sensor 108. .. When the engine control unit 201 determines in S106 that the time T2 has elapsed, the engine control unit 201 advances the process to S107.

In S107, the engine control unit 201 stops the drive of the pick roller 103 by the drive control unit 210, ends the paper feeding operation, and ends the measurement of the rotation speed of the separation roller 105 and the measurement of the elapsed time by the measurement unit 206. .. In S108, the engine control unit 201 stores the rotation speed of the separation roller 105 measured by the measurement unit 206 in the storage unit 209. In S109, the engine control unit 201 determines the life state of the separation roller 105 based on the rotation speed of the separation roller 105 measured by the measurement unit 206 by the determination unit 207, and ends the process. The processing of S109 will be described in detail later.

In S110, the engine control unit 201 determines whether or not the paper feed time being measured by the measurement unit 206 exceeds the threshold time Te set for determining that the feeding is defective. When the engine control unit 201 determines in S110 that the elapsed time does not exceed the threshold time Te, the process is returned to S102, and the drive control unit 210 maintains the drive of the pick roller 103 to continue the paper feeding operation. When the engine control unit 201 determines in S110 that the elapsed time exceeds the threshold time Te, the process proceeds to S111. In S111, the engine control unit 201 stops the drive of the pick roller 103 by the drive control unit 210 to end the paper feed operation, and ends the measurement of the paper feed time by the measurement unit 206. In S112, the engine control unit 201 determines that a transfer defect such as a delay misprint has occurred, notifies the user of the occurrence of the transfer defect via the panel 211 or an external device, and ends the process.

(Life determination process of separation roller 105)
Next, the life determination process of the separation roller 105 of S109 will be described with reference to FIG. In S201, the engine control unit 201 reads out the information on the rotation speed of the separation roller 105 stored in the storage unit 209. The engine control unit 201 calculates the average value Va1 of the rotation speeds of the separation rollers 105 during the period from when the tip of the paper S reaches the top sensor 108 until the time T1 elapses and then the time T2 elapses. In S202, in the engine control unit 201, the average value Va1 of the rotation speed of the separation roller 105 calculated in S201 is within the range of the upper and lower limit values of the preset average value Va1 (hereinafter referred to as the upper and lower limit value ranges). Judge whether or not. When the engine control unit 201 determines in S202 that the calculated average value Va1 of the rotation speed of the separation roller 105 is out of the upper / lower limit value range, the engine control unit 201 ends the life determination of the separation roller 105.

When the engine control unit 201 determines in S202 that the average value Va1 of the rotation speed of the separation roller 105 is within the preset upper and lower limit values range, the process proceeds to S203. In S203, the engine control unit 201 stores the average value Va1 of the rotation speed of the separation roller 105 calculated in S201 in the storage unit 209. When the average value Va1 of the rotation speed of the separation roller 105 is stored in the storage unit 209, it is stored together with the information of the stored time. In S204, the engine control unit 201 determines whether or not the number of data of the average value Va1 of the rotation speed of the separation roller 105 stored in the storage unit 209 is a predetermined number, for example, 11 or more. Here, the number of data stored in the storage unit 209 is not limited to 11.

When the engine control unit 201 determines in S204 that the number of data stored in the storage unit 209 is less than 11, the engine control unit 201 ends the life determination of the separation roller 105. When the engine control unit 201 determines in S204 that the number of data stored in the storage unit 209 is 11 or more, the process proceeds to S205. In S205, the engine control unit 201 deletes one of the 11 oldest data of the average value Va1 of the rotation speeds of the separation rollers 105 stored in the storage unit 209. In S206, the engine control unit 201 determines whether or not the life state of the separation roller 105 is at the Low level described above. The engine control unit 201 extracts the maximum value Va1_max and the minimum value Va1_min from the data of the ten average values Va1 stored in the storage unit 209, and obtains the difference between the maximum value Va1_max and the minimum value Va1_min. In the engine control unit 201, the difference between the maximum value Va1_max and the minimum value Va1_min, that is, the variation in the average value Va1 of the rotation speed of the separation roller 105 is from the life threshold value Low, which is the first threshold value for determining the Low level state. Judge whether it is large or not.

When the engine control unit 201 determines in S206 that the difference between the maximum value Va1_max and the minimum value Va1_min is the life threshold value Low or less (the first threshold value or less) and the variation of the average value Va1 is smaller than the life threshold value Low. The life determination of the separation roller 105 is completed. When the engine control unit 201 determines in S206 that the difference between the maximum value Va1_max and the minimum value Va1_min is larger than the life threshold Low, that is, the variation of the average value Va1 is larger than the life threshold Low, the process proceeds to S207.

In S207, the engine control unit 201 determines whether or not the difference between the maximum value Va1_max and the minimum value Va1_min is larger than the life threshold value Out, which is the second threshold value for determining the Out level state described above. The life threshold Out is larger than the life threshold Low. When the engine control unit 201 determines in S207 that the difference between the maximum value Va1_max and the minimum value Va1_min, that is, the variation of the average value Va1 is equal to or less than the life threshold Out (less than or equal to the second threshold value), the process proceeds to S209. .. In S209, the engine control unit 201 determines that the life state of the separation roller 105 is the Low level state, notifies the user using the panel 211 by the output unit 208, and ends the life determination of the separation roller 105. When the engine control unit 201 determines in S207 that the difference between the maximum value Va1_max and the minimum value Va1_min is larger than the life threshold Out, that is, the variation of the average value Va1 is larger than the life threshold Out, the process proceeds to S208. In S208, the engine control unit 201 determines that the life state of the separation roller 105 is the Out level state, notifies the user using the panel 211 by the output unit 208, and ends the life determination of the separation roller 105.

Here, the variation in the average value Va1 of the rotation speed of the separation roller 105 is the difference between the maximum value and the minimum value of the data recorded in the storage unit 209, but the standard deviation or the average from the data recorded in the storage unit 209. You may calculate and derive the value. The number of data of the average value Va1 of the rotation speed stored in the storage unit 209 may also be changed to an appropriate number of data depending on the method of calculating the variation. Further, in order to prevent erroneous detection due to sudden abnormal data, the life state of the separation roller 105 is the life when the variation of the average value Va1 of the rotation speed of the separation roller 105 exceeds the threshold value a plurality of times within a predetermined period. The Low level and Out level of the state may be determined.

In this way, the variation in the diameter of the separation roller 105 and the coefficient of friction on the surface, and the influence of the paper type of the paper S are minimized, and the life of the separation roller 105 including the sign that the life is reached before the occurrence of transfer failure occurs. The state can be judged more accurately. By notifying the user of the result of determining the life of the separation roller 105 and urging the user to replace the separation roller 105, it is possible to prevent transport defects such as misprints in the future. Further, when the separation roller 105 has not reached the end of its life, unnecessary replacement of the separation roller 105 can be prevented and the cost can be reduced. As described above, according to the first embodiment, the life state of the separation roller can be accurately determined.

The second embodiment will be described. The description of the main part is the same as that of the first embodiment, and here, only the part different from the first embodiment will be described.

<Explanation of Paper Feed Control in Example 2>
First, the paper feed control of the printer 101 in the second embodiment will be described with reference to FIGS. 10 and 11. 10 and 11 correspond to FIGS. 4 and 5, respectively, of the first embodiment. The description of FIG. 10A is the same as that of FIG. 4A, and corresponds to the timing Ta of FIG. 11A.

Next, FIG. 10B shows a cross-sectional view of the cassette 102 at the timing when the rear end (upstream end in the paper feeding direction) of the paper S1 reaches the position Pp of the nip portion of the pick roller 103. In the printer 101 of the second embodiment, a paper feeding method is adopted in which the paper S2 located below the paper S1 is partially overlapped with the paper S1 and fed. Therefore, in the second embodiment, the drive of the pick roller 103 is kept on even when the rear end of the paper S1 reaches the position Pp of the nip portion of the pick roller 103. When the rear end of the paper S1 passes through the pick roller 103, the pick roller 103 comes into contact with the paper S2 and feeds the paper S2 to the right. The timing Tb in the graph of FIG. 11 (A) corresponds to the state shown in FIG. 10 (b). At the timing Tb, the drive of the pick roller 103 remains on, and the separation roller 105 rotates following the conveyed paper S1.

Next, FIG. 10C shows a cross-sectional view of the cassette 102 at the timing when the tip of the paper S2 fed by the pick roller 103 reaches the position Pfr of the separation nip portion of the feed roller 106 and the separation roller 105. ing. As described above, when one sheet of paper S is conveyed, the separation roller 105 rotates in the clockwise direction to feed one sheet of paper S. However, when two or more sheets of paper S are conveyed, the separation roller 105 stops rotating or rotates in the counterclockwise direction, and one sheet of paper S is conveyed through two or more sheets of paper S. To separate. That is, the rotational state of the separation roller 105 changes. The timing Tc in the graph of FIG. 11 corresponds to the state shown in FIG. 10 (c). At the timing Tc, the tip of the paper S2 reaches the position Pfr of the separation nip portion, so that the rotation of the separation roller 105 is stopped. When the tip of the paper S2 reaches the position Pfr of the separation nip portion, the drive of the pick roller 103 is switched from on to off in order to prevent the paper S2 from being further pushed into the separation nip portion and causing a paper jam. Further, at this time, the drive of the feed roller 106 is also turned off, but the feed roller 106 is rotated following the paper S1.

Next, FIG. 10D shows a cross-sectional view of the cassette 102 at the timing after the rear end of the paper S1 has passed the position Pfr of the separation nip portion of the feed roller 106 and the separation roller 105. The timing Td in the graph of FIG. 11 (A) corresponds to the state shown in FIG. 10 (d). Since the paper S1 has passed the position Pfr of the separation nip portion, the rotation of the feed roller 106 has stopped.

As described above, in the printer 101 of the second embodiment, the pick roller 103 is provided on the condition that the tip of the paper S2 reaches the position Pfr of the separation nip portion and the rotation of the separation roller 105 is stopped or rotated in the opposite direction. Turn off the drive. The drive of the pick roller 103 may be turned off before the rotation of the separation roller 105 is stopped, provided that the rotation speed of the separation roller 105 is slower than a certain threshold speed. Since the paper S2 is overlapped with the paper S1 and the paper is fed in advance, the tip position of the paper S2 can be aligned with the position Pfr of the separation nip portion. Such a paper feeding method is hereinafter referred to as take-out paper feeding. By performing the take-out paper feeding, the distance between the rear end of the paper S1 and the front end of the paper S2 (hereinafter referred to as “paper spacing”) can be shortened when the paper feeding operation is continuously performed. That is, the number of prints per unit time and the productivity of the printer 101 can be improved.

<Detection of life of separation roller in Example 2>
Next, the influence on the paper feed control due to the deterioration of the transport performance due to the wear of the separation roller 105 and the like will be described with reference to FIG. 11B. FIG. 11B shows a state in which the transport performance of the separation roller 105 is deteriorated in the graph of FIG. 11A. When the frictional force of the separation roller 105 with respect to the paper S decreases and the separation roller 105 cannot be driven and rotated correctly with respect to the paper S, even when one sheet of paper S is being conveyed to the separation nip portion of the feed roller 106 and the separation roller 105. , The rotation of the separation roller 105 may stop. When the rotation of the separation roller 105 is stopped due to the deterioration of the transfer performance of the separation roller 105 at the timing Tc, the engine control unit 201 rotates the separation roller 105 because the tip of the paper S2 reaches the position Pfr of the separation nip portion. Will be judged to have stopped. Then, the engine control unit 201 turns off the drive of the pick roller 103. Since the drive of the pick roller 103 has been turned off at the timing Tc, the paper S2 is no longer fed. That is, in this case, the tip of the paper S2 is not fed to the position Pfr of the separation nip portion.

As described above, since the tip of the paper S2 has not reached the position Pfr of the separation nip portion, the separation roller 105 is transferred to the paper S1 conveyed by the register roller pair 107 even after the drive of the pick roller 103 is turned off. Follow and continue the driven rotation. At the timing Td, when the paper S1 passes through the position Pfr of the separation nip portion, the separation roller 105 stops the driven rotation. In this case, the space between the paper S1 and the paper S2 cannot be shortened, so that the productivity of the printer 101 is lowered.

Summarizing the above, FIG. 11A shows a state in which the drive of the pick roller 103 is turned off when the tip of the paper S2 reaches the position Pfr of the separation nip portion, and the take-out paper feed is successful. In FIG. 11A, the rotation of the separation roller 105 is stopped after the timing Tc. Further, FIG. 11B shows a state in which the drive of the pick roller 103 is turned off due to the deterioration of the transport performance of the separation roller 105 and the take-out paper feeding fails. In FIG. 11B, the rotation of the separation roller 105 is maintained after the timing Tc. That is, by monitoring whether or not the rotation of the separation roller 105 continues after the drive of the pick roller 103 is turned off, it is possible to determine whether the take-out paper feed is successful or the take-out paper feed fails. can. Therefore, in addition to the variation in the average value Va1 of the rotation speed of the separation roller 105, the life state of the separation roller 105 can be checked by monitoring the number of times the paper S2 has failed to be taken out and fed due to the deterioration of the transport performance of the separation roller 105. It is possible to make a more accurate judgment.

<Judgment processing of life status>
The method of determining the life state of the separation roller 105 in the second embodiment will be described with reference to the flowcharts of FIGS. 12 and 13. In FIG. 12, the processes of S301 to S306 are the same as the processes of S101 to S106 of FIG. 8, and the description thereof will be omitted. When the measurement time has elapsed in S306, the engine control unit 201 in S307 ends the measurement of the elapsed time by the measurement unit 206. Similar to the first embodiment, in the second embodiment as well, the rotation speed of the separation roller 105 can be measured while avoiding the timing when the rotation of the separation roller 105 is likely to fluctuate. The measurement of the rotation speed of the separation roller 105 for obtaining the average value Va1 of the rotation speed of the separation roller 105 ends according to the lapse of the measurement time T2. However, in the second embodiment, in order to monitor whether the rotation of the separation roller 105 is continued or stopped, the rotation speed of the separation roller 105 is measured by the measuring unit 206 even after the measurement time has elapsed. Will be continued.

In S308, the engine control unit 201 determines whether or not the rotation of the separation roller 105 has stopped based on the rotation speed of the separation roller 105 being measured by the measurement unit 206. If it is determined in S308 that the rotation of the separation roller 105 has not stopped and the rotation is continued, the process is returned to S308, and the measurement of the rotation speed of the separation roller 105 is continued. When the engine control unit 201 determines in S308 that the rotation of the separation roller 105 has stopped, the process proceeds to S309. In S309, the engine control unit 201 stops the drive of the pick roller 103 by the drive control unit 210, and ends the feeding operation.

In S310, the engine control unit 201 determines whether or not the rotation of the separation roller 105 continues even after the feeding operation is completed. When the engine control unit 201 determines in S310 that the rotation of the separation roller 105 does not continue, that is, it remains stopped, the process proceeds to S312. When the engine control unit 201 determines in S310 that the rotation of the separation roller 105 is continuing, it determines that the subsequent take-out paper feeding of the paper S2 has failed, and proceeds to the process in S311. In S311 the engine control unit 201 stores in the storage unit 209 information that the subsequent take-out paper feeding of the paper S2 has failed. In S312, the engine control unit 201 ends the measurement of the rotation speed of the separation roller 105 by the measurement unit 206. The process of S313 is the same as that of S108 of FIG. 8, and the description thereof will be omitted. In S314, the engine control unit 201 determines the life state of the separation roller 105 based on the rotation speed of the separation roller 105 measured by the measurement unit 206 by the determination unit 207. The processing of S314 will be described in detail later. The processing of S315 to S317 in FIG. 12 is the same as the processing of S110 to S112 in FIG. 8, and the description thereof will be omitted.

(Life determination process of separation roller 105)
Next, the life determination process of the separation roller 105 of S314 will be described with reference to FIG. The processing of S401 to S406 in FIG. 13 is the same as the processing of S201 to S206 of FIG. 9, and the description thereof will be omitted. When the engine control unit 201 determines in S406 that the variation in the average value Va1 is larger than the life threshold value Low, the process proceeds to S407. In S407, the engine control unit 201 reads out the take-out failure information stored in the storage unit 209. Based on the read out information of the take-out failure, the engine control unit 201 has a threshold number of times that the number of times the paper S2 has failed to be taken out is a predetermined frequency among the X times which is the predetermined number of times the paper feeding operation is performed. It is determined whether or not it is A (≦ X) or more (predetermined frequency or more).

When the engine control unit 201 determines in S407 that the number of times the take-out paper feed fails is less than the threshold number number A, the process proceeds to S410. In S410, the engine control unit 201 determines that the life state of the separation roller 105 is the Low 1 level state, which is the second state, notifies the user, and then ends the life determination of the separation roller 105. The life state Low1 level is a state in which the Low level state described in Example 1 is further subdivided. The Low1 level is a state before reaching the Low2 level, and is not a level at which transfer defects frequently occur due to a decrease in the transfer performance of the separation roller 105, and a state in which the productivity has not decreased.

If the engine control unit 201 determines in S407 that the number of times the take-out paper feed has failed is equal to or greater than the threshold number A, the process proceeds to S408. In S408, the engine control unit 201 determines whether or not the life state of the separation roller 105 is the Out level state described above. When the engine control unit 201 determines in S408 that the variation in the average value Va1 of the rotation speeds of the separation rollers 105 is equal to or less than the life threshold Out, the process proceeds to S411. In S411, the engine control unit 201 determines that the life state of the separation roller 105 is the Low2 level state, which is the first state, notifies the user, and then ends the life determination of the separation roller 105. The Low2 level is not yet a level at which transfer defects frequently occur due to a decrease in the transfer performance of the separation roller 105, but a failure in take-out paper feeding occurs and productivity is reduced.

When the engine control unit 201 determines in S408 that the variation in the average value Va1 of the rotation speeds of the separation rollers 105 is larger than the life threshold Out, the process proceeds to S409. In S409, the engine control unit 201 determines that the life state of the separation roller 105 is the Out level state, notifies the user, and then ends the life determination of the separation roller 105. In Example 2, for example, X = 10 and A = 2 are set in order to separate the Low1 level state and the Low2 level state. That is, when the paper feeding operation is performed 10 times, the Low 1 level state and the Low 2 level state are separated according to whether or not the number of times of failure of the take-out paper feeding stored in the storage unit 209 is 2 or more. In the second embodiment, the life of the separation roller 105 is determined based on the frequency of occurrence of the phenomenon that the separation roller 105 is stopped and then rotated again when the feeding is performed a plurality of times.

From the above, according to the second embodiment, there are the following effects in addition to the effects of the first embodiment. In the second embodiment, in an image forming apparatus provided with a paper feed control for performing advance paper feed (take-out paper feed) in which the tip position of the subsequent paper S2 is aligned with the separation nip portion, the average value Va1 of the rotation speed of the separation roller 105 is set. The life state of the separation roller 105 is determined according to the variation. In the second embodiment, further, by monitoring the failure of the take-out paper feed due to the deterioration of the transfer performance of the separation roller 105, the productivity is affected by the deterioration of the transfer performance of the separation roller 105 with higher accuracy. The life state of the separation roller 105 can be determined. In the paper feed configuration of the second embodiment, the process related to the number of failure of the take-out paper feed may be omitted, and the same control as that of the first embodiment may be performed.

In the above-mentioned Examples 1 and 2, the description has been made on the premise that the paper transport speed (process speed) does not change when the papers of different paper types are conveyed. However, the configuration may be such that the paper transport speed changes. For example, it is assumed that plain paper is conveyed at one-third speed and thick paper is conveyed at one-third speed. In this case, if the paper to be stored in the cassette 102 is changed from plain paper to thick paper in the middle, the rotation speed of the separation roller 105 changes according to the paper transport speed even though the separation roller 105 has not reached the end of its life. Apparently, the rotation speed of the separation roller 105 varies. As a result, it may be erroneously determined that the separation roller 105 has reached the end of its useful life. Therefore, when the paper transport speed changes, the detected rotation speed of the separation roller 105 is corrected according to the reference speed. For example, the rotation speed of the separation roller 105 detected when the paper is conveyed at the one-third speed is corrected to three times according to the reference speed (one-third speed).

103 Pickup roller 105 Separation roller 106 Feed roller 201 Engine control unit 203 Encoder

Claims (15)

It is a feeding rotating body that feeds a plurality of recording materials mounted on the mounting unit one by one, and feeds the first recording material at the highest level of the above-mentioned mounting unit, and the first recording material is fed. Following the passage of the rear end of the recording material, a feeding rotating body that feeds the second recording material below the first recording material by partially overlapping the first recording material.
A transport rotating body that transports the recording material fed by the feed rotating body, and a transport rotating body.
It is a separated rotating body that forms a nip portion with the transport rotating body, and when the first recording material is fed to the nip portion, it is rotated in a predetermined direction by the first recording material. When the first recording material and the second recording material overlap and are fed to the nip portion, the rotation is stopped in order to separate the first recording material and the second recording material. Or, with a separated rotating body that rotates in the direction opposite to the predetermined direction,
An output means that outputs a signal according to the rotational state of the separated rotating body, and
Based on the rotation speed of the separated rotating body represented by the signal from the output means, the feeding operation of the recording material by the feeding rotating body is controlled, and the tip of the second recording material is brought to the nip portion. A control means that controls to stop when it reaches,
In a feeding device with
The control means is represented by a signal from the output means during a predetermined period in which the separated rotating body is rotated in the predetermined direction while the first recording material is fed to the nip portion. A feeding device, characterized in that the life of the separated rotating body is determined based on the variation in the average value of the rotational speeds of the separated rotating body. When the rotation speed of the separated rotating body represented by the signal from the output means is faster than the threshold speed, the control means continues the feeding operation by the feeding rotating body, so that the first recording material is used. When the rotation speed of the separated rotating body represented by the signal from the output means becomes slower than the threshold speed by performing the feeding operation of the second recording material following the feeding operation of the above. A state in which the tip of the second recording material reaches the nip portion by instructing the feeding rotating body to stop the feeding operation of the second recording material before the separated rotating body stops rotating. The feeding device according to claim 1, wherein the feeding device is controlled so as to stop at. The control means is based on the frequency at which the phenomenon of continuous rotation of the separated rotating body occurs after instructing the feeding rotating body to stop the feeding operation of the second recording material. The feeding device according to claim 2, wherein the life of the device is determined. Further, it has a detecting means for detecting the recording material conveyed by the conveying rotating body, and has a detection means.
The feeding device according to any one of claims 1 to 3, wherein the predetermined period is set based on the timing at which the detection means detects the tip of the first recording material. It also has a storage unit to store information,
The control means obtains an average value of the rotation speeds of the separated rotating bodies in the predetermined period, and stores the average value in the storage unit each time the recording material is fed by the feeding rotating body. From the plurality of average values stored in the storage unit, the maximum value of the average value and the minimum value of the average value are obtained, and the difference between the maximum value and the minimum value is the rotation of the separated rotating body. The feeding device according to any one of claims 1 to 4, wherein the mean value of the speed varies. The feeding device according to claim 5, wherein the control means does not determine the life of the separated rotating body when the difference is equal to or less than the first threshold value. The sixth aspect of claim 6, wherein the control means determines that the separated rotating body has reached the end of its life when the difference is larger than the second threshold value larger than the first threshold value. Feeding device. The control means is characterized in that when the difference is larger than the first threshold value and is equal to or less than the second threshold value, it is determined that the separated rotating body is in a state before reaching the end of its life. The feeding device according to claim 7. The feeding device according to claim 5, wherein the control means does not determine the life of the separated rotating body when the average value is out of a predetermined range. The feeding device according to claim 5, wherein the control means does not determine the life of the separated rotating body until the number of the average values stored in the storage unit reaches a predetermined number. It is a feeding rotating body that feeds a plurality of recording materials mounted on the mounting unit one by one, and feeds the first recording material at the highest level of the above-mentioned mounting unit, and the first recording material is fed. Following the passage of the rear end of the recording material, a feeding rotating body that feeds the second recording material below the first recording material by partially overlapping the first recording material.
A transport rotating body that transports the recording material fed by the feed rotating body, and a transport rotating body.
It is a separated rotating body that forms a nip portion with the transport rotating body, and when the first recording material is fed to the nip portion, it is rotated in a predetermined direction by the first recording material. When the first recording material and the second recording material overlap and are fed to the nip portion, the rotation is stopped in order to separate the first recording material and the second recording material. Or, with a separated rotating body that rotates in the direction opposite to the predetermined direction,
An output means that outputs a signal according to the rotational state of the separated rotating body, and
Based on the rotation speed of the separated rotating body represented by the signal output from the output means, the feeding operation of the recording material by the feeding rotating body is controlled, and the tip of the second recording material is the nip. A control means that controls the vehicle to stop when it reaches the unit,
In a feeding device with
The control means is based on the rotational speed of the separated rotating body represented by the signal output from the output means after the rotation of the separated rotating body is stopped and the drive of the feeding rotating body is turned off. , A feeding device for determining the life of the separated rotating body. The feeding device according to any one of claims 1 to 11, further comprising a display unit that displays a result determined by the control means. The output means is provided coaxially with the separated rotating body, includes a chord wheel that rotates together with the separated rotating body, and outputs a signal according to the rotation state of the code wheel. The feeding device according to any one of 12. Further having a motor and an electromagnetic clutch that transmits or disconnects the driving force from the motor to the feed rotating body and the transport rotating body.
When the control means instructs the start of the feeding operation by the feeding rotating body, the electromagnetic clutch transmits the driving force from the motor to each rotating body, and the controlling means feeds by the feeding rotating body. The feeding device according to any one of claims 1 to 13, wherein the electromagnetic clutch shuts off the driving force from the motor with respect to the respective rotating bodies when the feeding operation is instructed to be stopped. .. The other end is fixed and further has a torque limiter that gives a load to the separated rotating body.
The load is defeated by the force received from the first recording material when the first recording material is fed to the nip portion, and the first recording material and the second recording material overlap each other. The feeding device according to claim 14, wherein the feeding device is set so as to overcome the force received from the second recording material when fed to the nip portion.

Images