JP2006182553A - Paper feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid a trouble in well forming an image due to the occurrence of slip between a feed roller and paper. <P>SOLUTION: An ideal time A is subtracted from a time from starting the rotation of the feed roller (TA1, TA4) to passing the front end of the paper through a feed switch (TA2, TA6), to calculate a slip time (C1, C2). Then, at feeding the paper, the rotation of the feed roller is started the calculated slip time faster than a timing (TA5, TA9) when the feed switch is predicted to be in an off-state, to start the feed of the next paper (TA4, TA8). Thus, there is no difference between the time from starting the rotation of the feed roller to passing the front end of the paper through the feed switch and the ideal time A to passing the front end of the paper through the feed switch when no sip occurs between the feed roller and the paper. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sheet feeding device that is applied to an image forming apparatus such as a copying machine and can feed out a plurality of sheets set in a sheet setting section one by one.

  An image forming apparatus such as a copying machine has a paper setting unit that can set a plurality of sheets, and feeds the paper set in the paper setting unit one sheet at a predetermined time interval. In some cases, images can be continuously formed on each sheet (see, for example, Patent Document 1). The paper fed by the paper feed roller is guided to a predetermined position (for example, an image forming unit) through the paper transport path. For example, a feed switch for detecting a passing sheet is disposed in the sheet conveyance path.

In this type of image forming apparatus, slippage may occur between the paper feed roller and the paper when the paper feed roller feeds the paper one by one due to deterioration of the surface of the paper feed roller.
FIG. 6 is a timing chart showing a flow of operation states of the paper feed roller and the feed switch when the paper is fed one by one in the conventional image forming apparatus. FIG. When slip does not occur, (b) shows a case where slip occurs between the paper feed roller and the paper.

  If slip does not occur between the paper feed roller and the paper, as shown in FIG. 6A, in response to an operation such as operating a start key provided in the image forming apparatus, After the rotation of the paper roller is started (timing TB1), the time until the leading edge of the paper sent to the paper transport path reaches the feed switch and the feed switch is turned on (timing TB2) is constant. The constant value (ideal time A) depends on the distance between the paper feed roller and the feed switch.

  The feed roller is stopped after the trailing edge of the sheet being fed to the sheet conveying path has passed (timing TB3), and then the trailing edge of the sheet has passed the feed switch and the feed switch has been turned off. At that time (timing TB4), the rotation is started again and the next sheet is sent out. The time from when the feed switch is turned on to when it is turned off, that is, the time from when the leading edge of the paper reaches the feed switch until the trailing edge of the paper passes the feed switch is constant, and the paper It becomes a constant value (paper passing time B) depending on the size of.

  On the other hand, if a slip occurs between the paper feed roller and the paper, the time for the leading edge of the paper to reach the feed switch is delayed by the time during which the slip occurs (slip time CN (N is a natural number)). Will be. That is, as shown in FIG. 6B, in response to an operation such as operation of the start key, the rotation of the paper feed roller is started (timing TC1), and then the paper fed to the paper transport path is The time from when the tip reaches the feed switch until the feed switch is turned on (timing TC2) is a value obtained by adding the slip time CN to the ideal time A.

Also in this case, the paper feed roller is stopped after the trailing edge of the paper being fed to the paper conveyance path has passed (timing TC3), and then the trailing edge of the paper passes the feed switch and the feed switch is turned off. When the state is reached (timing TC4), the rotation is started again, and the next sheet is sent out.
JP-A-8-6330

  In the above configuration, the next sheet is detected when the trailing edge of the sheet passes through the feed switch and the feed switch is turned off regardless of whether or not slippage has occurred between the sheet feeding roller and the sheet. Therefore, when a slip occurs between the paper feed roller and the paper, the interval between the papers that are continuously fed (inter-paper) becomes long. In this case, there is a possibility that an image cannot be formed at a desired position on the paper and an image cannot be formed satisfactorily.

  The present invention has been made under such a background, and provides a paper feeding device that can prevent a good image from being formed due to slippage between a paper feeding roller and paper. With the goal.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a sheet setting section (2) on which a plurality of sheets can be set and a sheet set in the sheet setting section for sending out one sheet at a time. The sheet feeding roller (3) to be rotated, the sheet conveying path (5) for conveying the sheet fed by the sheet feeding roller, and the sheet feeding roller after the rotation of the sheet feeding roller is started. No slippage occurs between the time measuring means (7, 8, 9, S2 to S4) for measuring the time until the fed paper passes the predetermined position on the paper conveyance path and the paper feeding roller and the paper. The ideal time storage means (10) for storing the ideal time (A) until the paper fed by the paper feed roller passes the predetermined position on the paper transport path, and the time measuring means. Above measured time The slip time calculation means (8, S5) for calculating the slip time (CN) obtained by subtracting the ideal time stored by the ideal time storage means, and the slip time calculated by the slip time calculation means during subsequent sheet feeding. The sheet feeding device (1) includes control means (8, S6) for controlling the timing for starting the rotation of the sheet feeding roller.

The alphanumeric characters in parentheses indicate corresponding components in the embodiments described later. The same applies hereinafter.
According to this configuration, the timing for starting the rotation of the paper feed roller during the subsequent paper feed can be advanced by the slip time calculated by the slip time calculating means. As a result, the paper is transported when there is no slip between the time from when the paper feed roller starts to rotate until the paper passes the predetermined position on the paper transport path and between the paper feed roller and the paper. Since it is possible to eliminate the deviation from the ideal time to pass the predetermined position on the road, even when slipping occurs, it is not possible to form an image at a desired position on the paper, and a good image can be obtained. Can be formed.

  According to the second aspect of the present invention, there is provided a sheet setting section (2) capable of setting a plurality of sheets and a sheet feeding roller (rotated to feed out the sheets set in the sheet setting section one by one. 3), a sheet conveyance path (5) for conveying the sheet fed by the paper feed roller, and the paper fed by the paper feed roller after the rotation of the paper feed roller is started. When there is no slip between the time measuring means (7, 8, 9, E2 to E4) for measuring the time until it passes the predetermined position on the transport path and the paper feed roller and the paper, the paper feed The ideal time storage means (10) for storing the ideal time (A) until the paper fed by the roller passes through the predetermined position of the paper transport path, and the ideal time from the time measured by the time measuring means. By storage means The slip time calculating means (8, E5) for calculating the slip time (CN) obtained by subtracting the remembered ideal time, and the average value of the slip times calculated by the slip time calculating means for a plurality of times of paper feeding. Average value calculation means (8, E7) to be calculated, and control for performing control so as to advance the timing for starting the rotation of the paper feed roller during the subsequent paper feed by the average value of the sliding time calculated by the average value calculation means Means (8, E8).

  According to this configuration, the average value of the sliding time can be calculated, and the timing for starting the rotation of the paper feeding roller during the subsequent paper feeding can be advanced by the average sliding time. Therefore, it is possible to prevent variations in the timing for starting the rotation of the paper feed roller due to an error in the slip time calculated by the slip time calculating means, and thus an image can be formed more satisfactorily.

  According to the third aspect of the present invention, there is provided a sheet setting section (2) capable of setting a plurality of sheets, and a sheet feeding roller (rotated to feed out the sheets set in the sheet setting section one by one. 3), a sheet conveyance path (5) for conveying the sheet fed by the paper feed roller, and the paper fed by the paper feed roller after the rotation of the paper feed roller is started. When slipping does not occur between the time measuring means (7, 8, 9, P2 to P4) for measuring the time required to pass the predetermined position on the conveyance path and the paper feeding roller and the paper, the paper feeding is performed. The ideal time storage means (10) for storing the ideal time (A) until the paper fed by the roller passes through the predetermined position of the paper transport path, and the ideal time from the time measured by the time measuring means. By storage means A slip time calculating means (8, P5) for calculating a slip time (CN) obtained by subtracting the remembered ideal time, and whether the slip time calculated by the slip time calculating means is equal to or less than a predetermined threshold value. Of the slip times calculated by the determination means (8, E6) and the slip time calculation means when feeding a plurality of times, the average value of the slip times determined by the determination means to be equal to or less than the predetermined threshold value The average value calculating means (8, P8) for calculating the value and the average value of the sliding time calculated by the average value calculating means are controlled so as to advance the timing for starting the rotation of the paper feed roller during the subsequent paper feed. And a control unit (8, P9).

  According to this configuration, when an extremely long slip time occurs due to the type of paper, the average value of the slip time excluding the slip time is calculated, and only the average slip time is used thereafter. The timing of starting the rotation of the paper feed roller during paper can be advanced. Therefore, it is possible to more effectively prevent variations in the timing at which the rotation of the paper feed roller is started due to an error in the calculated slip time, so that an image can be formed more satisfactorily.

Embodiments of the present invention will be specifically described below with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a sheet feeding device 1 according to an embodiment of the present invention.
Referring to FIG. 1, this paper feeding device 1 is applied to an image forming apparatus such as a copying machine, a facsimile machine, or a printer, for example, and feeds paper one by one at a predetermined time interval so as to continuously feed those papers. Thus, an image can be formed (transferred) by the image forming unit provided in the image forming apparatus.

  The configuration of the image forming unit is a known configuration including, for example, a photoreceptor, a main charger, a developing device, a transfer device, and the like. That is, at the time of image formation, the surface of the substantially cylindrical photoconductor is uniformly charged by the main charger, and the surface of the photoconductor is irradiated with light based on image data, so that the surface of the photoconductor is so-called static. An electrostatic latent image is formed. On the surface of the photoconductor on which the electrostatic latent image is formed, toner is selectively attached by a developing device to form a toner image. The toner image formed on the surface of the photoconductor is transferred onto the paper by the action of the transfer device.

  The paper feeding device 1 includes a paper cassette 2 that can accommodate a plurality of sheets stacked, a paper feeding roller 3 that feeds the paper stored in the paper cassette 2 one by one from above, A motor 4 for rotationally driving the paper feed roller 3, a paper transport path 5 for transporting the paper fed from the paper feed roller 3 to a predetermined position (for example, an image forming unit), and in the paper transport path 5 Two pairs of conveying rollers 6 rotated to convey a sheet of paper, and a feed switch for detecting a sheet passing through a predetermined position (for example, between two pairs of conveying rollers 6) of the sheet conveying path 5 7 is provided.

  The paper feeding device 1 is provided with a control unit 8 including a microcomputer. The control unit 8 includes a timer 9 for measuring time and a memory 10 capable of storing various data. The control unit 8 is electrically connected to the motor 4, the feed switch 7, and the like, and the control unit 8 controls the operation of the control target such as the motor 4 based on an input signal from the feed switch 7. It will be.

FIG. 2 is a flowchart showing the contents of control by the control unit 8 when the sheets are fed from the sheet cassette 2 one by one. FIG. 3 is a timing chart showing a flow of operation states of the paper feed roller 3 and the feed switch 7 when the paper is fed from the paper cassette 2 one by one.
Referring to FIGS. 2 and 3, for example, in response to an operation such as operating a start key (not shown) provided in the image forming apparatus, rotation of paper feed roller 3 is started and When the paper feeding operation (paper feeding) by the paper device 1 is started (YES in step S1; timing TA1 in FIG. 3), the control unit 8 starts time measurement by the timer 9 (step S2). Thereafter, when the sheet is sent out to the sheet conveyance path 5 and the leading edge of the sheet reaches the feed switch 7, the feed switch 7 is turned on (YES in step S3; timing TA2 in FIG. 3), and the control unit 8 sets a timer. The time counting by 9 is terminated (step S4). The paper feed roller 3 is stopped after the trailing edge of the paper fed to the paper transport path 5 passes through the paper feed roller 3 (timing TA3).

  If no slip occurs between the paper feed roller 3 and the paper, the time from when the paper feed roller 3 starts to rotate (after the paper feed is started) until the leading edge of the paper reaches the feed switch 7 is It is constant and becomes a constant value (ideal time A) depending on the distance (for example, about 200 mm) between the paper feed roller 3 and the feed switch 7 (see FIG. 6A). However, when a slip occurs between the paper feed roller 3 and the paper, the time for the leading edge of the paper to reach the feed switch 7 only during the time when the slip occurs (slip time CN (N is a natural number)). Will be delayed (see FIG. 6B). This sliding time CN is, for example, about 10 msec.

The ideal time A is stored in the memory 10 of the control unit 8, and the control unit 8 ends the time measurement by the timer 9 (step S4), and then the ideal time stored in the memory 10 from the measured time. By subtracting A, the slip time C1 is calculated (step S5).
Here, the time from when the feed switch 7 is turned on to when it is turned off, that is, the time from when the leading edge of the paper reaches the feed switch 7 until the trailing edge of the paper passes through the feed switch 7 is It is constant and becomes a constant value (paper passing time B) depending on the paper size. Therefore, the control unit 8 determines when the feed switch 7 is turned off based on the timing TA2 when the feed switch 7 is turned on and the sheet passing time B determined based on the paper size (FIG. 3). The timing TA5) can be predicted.

  After calculating the sliding time C1 (step S5), the control unit 8 starts the rotation of the paper feed roller 3 earlier than the timing TA5 at which the feed switch 7 is predicted to be turned off by the calculated sliding time C1. Then, the feeding of the next sheet is started (step S6; timing TA4 in FIG. 3), and the timing by the timer 9 is started (step S2). Thereafter, when the sheet is sent out to the sheet conveyance path 5 and the leading edge of the sheet reaches the feed switch 7, the feed switch 7 is turned on (YES in step S3; timing TA6 in FIG. 3), and the control unit 8 sets a timer. The time counting by 9 is terminated (step S4). The paper feed roller 3 is stopped after the trailing edge of the paper fed to the paper transport path 5 passes through the paper feed roller 3 (timing TA7).

  Thereafter, the control unit 8 calculates the slip time C2 by subtracting the ideal time A stored in the memory 10 from the time measured by the timer 9 (step S5). Then, the control unit 8 starts the rotation of the paper feed roller 3 earlier than the timing TA9 at which the feed switch 7 is predicted to be turned off by the calculated sliding time C2, and starts the feeding of the next paper. At the same time (step S6; timing TA8 in FIG. 3), the timer 9 starts timing (step S2).

In this way, the control unit 8 repeats the control of steps S2 to S6, and ends the control for paper feeding when all the papers stored in the paper cassette 2 have been sent out.
In this embodiment, the timing for starting the rotation of the paper feed roller 3 during the subsequent paper feed can be advanced by the calculated slip time CN. As a result, when no slip occurs between the time from when rotation of the paper feed roller 3 starts until the leading edge of the paper passes the feed switch 7 of the paper transport path 5 and between the paper feed roller 3 and the paper. In addition, since the deviation from the ideal time A until the leading edge of the paper passes the feed switch 7 of the paper conveyance path 5 can be eliminated, an image can be formed at a desired position on the paper even if slippage occurs. An image can be formed satisfactorily without disappearing.

FIG. 4 is a flowchart showing a first modified example of the contents of control by the control unit 8 when the sheets are fed from the sheet cassette 2 one by one.
Referring to FIG. 4, for example, in response to an operation such as operating a start key (not shown) provided in the image forming apparatus, rotation of sheet feeding roller 3 is started and sheet feeding apparatus 1 is started. Is started (YES in step E1), the control unit 8 starts timing by the timer 9 (step E2). Thereafter, when the sheet is sent out to the sheet conveyance path 5 and the leading edge of the sheet reaches the feed switch 7, the feed switch 7 is turned on (YES in step E3), and the control unit 8 ends the time measurement by the timer 9. (Step E4).

  Thereafter, the control unit 8 calculates the slip time CN by subtracting the ideal time A stored in the memory 10 from the time measured by the timer 9 (step E5), and stores the slip time CN in the memory 10. Store (step E6). Then, the control unit 8 calculates an average value of the slip times CN for the past predetermined number of times (for example, the past 100 times) stored in the memory 10 (step E7). Thereafter, the control unit 8 starts the rotation of the paper feed roller 3 earlier than the timing at which the feed switch 7 is predicted to be turned off by an average value of the calculated sliding time CN, and feeds the next paper. At the same time, the timer 9 starts measuring time (step E2).

In this way, the control unit 8 repeats the control of steps E2 to E6, and ends the control for paper feeding when all the paper stored in the paper cassette 2 has been sent out.
In this modification, the average value of the sliding time CN is calculated, and the timing for starting the rotation of the paper feeding roller 3 during the subsequent paper feeding can be advanced by the average sliding time. Therefore, it is possible to prevent variations in the timing for starting the rotation of the paper feed roller 3 due to an error in the calculated slip time, so that an image can be formed more satisfactorily than the configuration as in the above embodiment. be able to.

FIG. 5 is a flowchart showing a second modified example of the control content by the control unit 8 when the sheets are sent out from the sheet cassette 2 one by one.
Referring to FIG. 5, for example, in response to an operation such as operating a start key (not shown) provided in the image forming apparatus, the rotation of the sheet feeding roller 3 is started, and the sheet feeding apparatus 1. Is started (YES in step P1), the control unit 8 starts measuring time by the timer 9 (step P2). Thereafter, when the sheet is sent out to the sheet conveyance path 5 and the leading edge of the sheet reaches the feed switch 7, the feed switch 7 is turned on (YES in Step P3), and the control unit 8 ends the time measurement by the timer 9. (Step P4).

  Thereafter, the control unit 8 calculates the slip time CN by subtracting the ideal time A stored in the memory 10 from the time measured by the timer 9 (step P5). At this time, if the calculated slip time CN is equal to or less than a predetermined threshold (specifically, 5% or less of the ideal time A (eg, 46 msec or less)) (YES in Step P6), the control unit 8 performs the slip. The time CN is stored in the memory 10 (step P7), and the average value of the slip times CN for the past predetermined number of times stored in the memory 10 is calculated (step P8). On the other hand, if the calculated sliding time CN is longer than the predetermined threshold value (NO in step P6), the control unit 8 does not store the sliding time CN in the memory 10, but otherwise stores it in the memory 10. The average value of the sliding time CN for the past predetermined number of times is calculated (step P8).

Thereafter, the control unit 8 starts the rotation of the paper feed roller 3 earlier than the timing at which the feed switch 7 is predicted to be turned off by an average value of the calculated sliding time CN, and feeds the next paper. While starting (step P9), the time measurement by the timer 9 is started (step P2).
In this way, the control unit 8 repeats the control of steps P2 to P9, and ends the control for paper feeding when all the papers stored in the paper cassette 2 have been sent out.

  In this modification, when an extremely long slip time CN occurs due to the type of paper or the like, an average value of the slip times CN for the past predetermined number of times excluding the slip time CN is calculated, and the average value is calculated. The timing for starting the rotation of the paper feed roller 3 during the subsequent paper feed can be advanced by the slip time. Therefore, as compared with the configuration as in the first modification, it is possible to more effectively prevent variations in the timing at which the rotation of the paper feed roller 3 is started due to an error in the calculated slip time CN. An image can be formed more satisfactorily.

The present invention is not limited to the contents of the above embodiments, and various modifications can be made within the scope of the claims.
For example, in the first and second modified examples, when the average value of the sliding time CN is calculated (steps E7 and P8), the average value of the sliding time CN for a predetermined number of past times is calculated. Instead, the average value of all past slip times CN stored cumulatively in the memory 10 may be calculated.

The paper to be used is not limited to a configuration in which the paper is stored in a stacked state in a paper cassette 2 provided in the paper feeding device 1. For example, the paper used is stacked on a paper tray provided outside the paper feeding device 1. It may be configured to be placed in a state.
In the above-described embodiment and modification, the sheet feeding apparatus 1 that feeds the sheet used to form an image has been described as an example. However, the present invention is not limited to this type of sheet feeding apparatus, and is applied to a scanner. The present invention can also be applied to a paper feeding device (original conveying device) that sends out originals one by one.

1 is a block diagram illustrating a configuration of a sheet feeding device according to an embodiment of the present invention. It is a flowchart which shows the control content by the control part at the time of sending out one sheet of paper from a paper cassette. 6 is a timing chart showing a flow of operation states of a paper feed roller and a feed switch when paper is fed from a paper cassette one by one. It is a flowchart which shows the 1st modification of the control content by the control part at the time of sending out one sheet of paper from a paper cassette. It is a flowchart which shows the 2nd modification of the control content by the control part at the time of sending out the sheet | seat one sheet at a time from a paper cassette. FIG. 6A is a timing chart showing a flow of operation states of a paper feed roller and a feed switch when paper is fed one by one in a conventional image forming apparatus, in which (a) shows a slip between the paper feed roller and the paper. When there is no slip, (b) shows a case where slip occurs between the paper feed roller and the paper.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Paper feeder 2 Paper cassette 3 Paper feed roller 5 Paper conveyance path 7 Feed switch 8 Control part 9 Timer 10 Memory

Claims (3)

A paper set section that can set multiple sheets of paper,
A paper feed roller that is rotated to feed the paper set in the paper setting section one by one;
A paper transport path for transporting the paper fed by the paper feed roller;
Time measuring means for measuring the time from when rotation of the paper feed roller is started until the paper fed by the paper feed roller passes through a predetermined position of the paper transport path;
An ideal time that stores an ideal time until the paper fed by the paper feed roller passes the predetermined position on the paper transport path when no slip occurs between the paper feed roller and the paper. Storage means;
A slip time calculating means for calculating a slip time obtained by subtracting the ideal time stored in the ideal time storage means from the time measured by the time measuring means;
And a control unit that performs control so as to advance the timing at which the rotation of the sheet feeding roller is started during the subsequent sheet feeding by the slip time calculated by the slip time calculating unit. A paper set section that can set multiple sheets of paper,
A paper feed roller that is rotated to feed the paper set in the paper setting section one by one;
A paper transport path for transporting the paper fed by the paper feed roller;
Time measuring means for measuring the time from when rotation of the paper feed roller is started until the paper fed by the paper feed roller passes through a predetermined position of the paper transport path;
An ideal time that stores an ideal time until the paper fed by the paper feed roller passes the predetermined position on the paper transport path when no slip occurs between the paper feed roller and the paper. Storage means;
A slip time calculating means for calculating a slip time obtained by subtracting the ideal time stored in the ideal time storage means from the time measured by the time measuring means;
An average value calculating means for calculating an average value of the sliding time respectively calculated by the sliding time calculating means when feeding a plurality of times;
And a control unit that performs control so as to advance the timing for starting the rotation of the sheet feeding roller during the subsequent sheet feeding by the average value of the sliding time calculated by the average value calculating unit. A paper set section that can set multiple sheets of paper,
A paper feed roller that is rotated to feed the paper set in the paper setting section one by one;
A paper transport path for transporting the paper fed by the paper feed roller;
Time measuring means for measuring the time from when rotation of the paper feed roller is started until the paper fed by the paper feed roller passes through a predetermined position of the paper transport path;
An ideal time that stores an ideal time until the paper fed by the paper feed roller passes the predetermined position on the paper transport path when no slip occurs between the paper feed roller and the paper. Storage means;
A slip time calculating means for calculating a slip time obtained by subtracting the ideal time stored in the ideal time storage means from the time measured by the time measuring means;
Determining means for determining whether the slip time calculated by the slip time calculating means is equal to or less than a predetermined threshold;
An average value calculating means for calculating an average value of the sliding times determined by the determining means to be equal to or less than the predetermined threshold among the sliding times calculated by the sliding time calculating means at the time of feeding a plurality of times;
And a control unit that performs control so as to advance the timing for starting the rotation of the sheet feeding roller during the subsequent sheet feeding by the average value of the sliding time calculated by the average value calculating unit.

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