JPH1159968A - Paper carrying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the operation to solve a problem of paper sheet jamming by setting the feed level of the drive energy of a paper sheet carrying means to be higher than the stationary level when paper sheet jamming is detected on a paper sheet carrying passage to feed forward the paper sheet located in the middle of the paper sheet carrying passage to the prescribed position. SOLUTION: In forming the image, a controller judges whether or not paper sheet jamming is generated on a paper sheet carrying passage by the detected signals of paper sheet detection sensors 20-22 appropriately arranged in the paper sheet carrying passage. For example, when detection of the paper sheet by the paper sheet detection sensor 20 downstream thereof is not present after the paper sheet is detected by the paper sheet detection sensor 21, it is judged that paper sheet jamming is generated at a middle point of the paper sheet carrying passage from pre-resist rolls 5a, 5b to resist rolls 7a, 7b. The current to be applied to a motor 8 is controlled so as to be larger than the stationary value. The succeeding paper sheet across slide units is fed to the prescribed position where the jamming removal work can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper transport device incorporated in an image forming apparatus such as a copying machine, a printer, a facsimile, and the like.

[0002]

2. Description of the Related Art Generally, in a sheet transporting device incorporated in an image forming apparatus such as a copying machine, when a sheet running in a sheet transporting path is jammed for some reason (jam), the jammed sheet (hereinafter referred to as "jam"). Various proposals have been made to remove jammed paper without hindrance. For example, Japanese Unexamined Patent Publication
Japanese Patent Application Laid-Open No. 163244 discloses that when a paper jam occurs on a paper transport path, a sheet (hereinafter, a succeeding sheet) after the jammed paper causing the jam (hereinafter, a succeeding sheet) is positioned at a position where there is no problem when the jammed paper is removed (hereinafter, referred to as a sheet). , A predetermined position), and then stop the sheet conveying operation.

[0003]

However, the prior art described in the above publication has the following problems. That is, when the succeeding paper is fed to a predetermined position when a paper jam occurs, if the succeeding paper collides with the jammed paper at the end thereof, the conveyance resistance of the paper significantly increases. As a result, an excessive load is applied to a motor serving as a driving source for sheet conveyance, causing a step-out or the like, and a problem that a subsequent sheet cannot be fed to a predetermined position occurs. As a countermeasure, it is conceivable to use a large motor that can obtain a larger paper conveyance force. Problems arise.

[0004]

According to the present invention, there is provided a sheet conveying device for conveying a sheet along a sheet conveying path, a detecting means for detecting occurrence of a paper jam on the sheet conveying path, When the occurrence of paper jam is detected by this detection means, the supply level of the driving energy to the drive source of the paper conveyance means is set to be larger than that in the normal state, and the paper positioned in the middle of the paper conveyance path is moved to a predetermined position. And a control means for controlling the driving of the sheet conveying means to feed the sheet.

In the paper transport apparatus having the above configuration, when the occurrence of a paper jam on the paper transport path is detected by the detection means, the control means changes the supply level of the driving energy to the drive source of the paper transport means from a steady state. Is set large, so that even if the transport resistance increases due to the collision between papers,
It is possible to reliably feed the paper being transported to a predetermined position.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic side view showing an example of a mechanical configuration of a sheet conveying device to which the present invention is applied. In FIG. 1, a sheet to be conveyed is set in a sheet cassette (not shown), and a pair of feed rollers 1a and 1b are arranged on the sheet feeding side of the sheet cassette. A first chute guide 2 extends diagonally upward in an arc shape downstream of the pair of delivery rolls 1a, 1b in the direction of conveyance, and a pair of takeaway rolls 3a, 3b are provided near the extended ends thereof. It is arranged.

Further, a pair of take away rolls 3a,
A pair of second chute guides 4a and 4b are linearly extended obliquely upward on the downstream side of the conveyance of the pre-registration roll 5b.
a, 5b are provided. Further, on the downstream side of the pair of pre-registration rolls 5a and 5b, a pair of third
The chute guides 6a and 6b extend upward in a substantially U-shape, and a pair of registration rolls 7a and 7b are disposed near the extended ends thereof.

Further, a motor 8 serving as a driving source for transporting the paper is provided near the takeaway rolls 3a and 3b. A motor gear 9 is attached to an output shaft (rotation shaft) of the motor 8. A two-stage gear 10 in which two large and small gears are coaxially arranged is meshed with the motor gear 9. One of the two teeth of the two-stage gear 10 is meshed with a drive gear 11 for rotating the take-away rolls 3a and 3b, and the other tooth is pre-registered via an idle gear 12. Roll 5
a and 5b are engaged with a drive gear 13 for rotating the same.

On the other hand, in the vicinity of the registration rolls 7a and 7b, a gate member 14 for temporarily stopping the paper before the registration rolls 7a and 7b is provided. The tip of the gate member 14 is formed to be bent in a key shape. The rear end of the gate member 14 is attached to the rotation shaft 15. This rotating shaft 1
A swing member 16 whose one end side is bifurcated is attached to the end of 5, and the fork portion of the swing member 16 is engaged with a movable rod 18 of a solenoid 17 via a pin 19. I have. In addition, a paper detection sensor 20 is provided just before the paper stop position by the gate member 14. Further, sheet detection sensors 21 and 22 are provided on the downstream side of the transport of the pre-registration rolls 5a and 5b and on the upstream side of the transport of the takeaway rolls 3a and 3b, respectively.

In addition, a photosensitive drum 23 and a transfer unit 24 are disposed on the downstream side of the registration rolls 7a and 7b in the conveyance state. On the outer peripheral surface of the photosensitive drum 23,
A visible image (a toner image or the like) is formed by an image output means (a laser scanner, a developing device or the like) not shown. Then, when a sheet is fed between the photosensitive drum 23 and the transfer unit 24, the visible image formed on the outer peripheral surface of the drum is transferred onto the sheet by the transfer unit 24.

Further, when a paper jam occurs on the paper transport path, a mechanical component (pre-resist) between the take-away rolls 3a and 3b and the photosensitive drum 23 is used so that the jammed paper can be removed easily and quickly. Roll 5a, 5
b, the chute guides 4a, 4b, 6a, 6b, the resist rolls 7a, 7b, the transfer unit 24, etc.) are supported by the slide unit U. And this slide unit U
Can be pulled out to the near side along the axial direction of the photosensitive drum 23.

FIG. 2 is a block diagram showing an example of the configuration of a control system of the sheet conveying device according to the present invention. In FIG. 2, a controller 25 controls the operation of each part of the sheet transport device, and detection signals from the above-described sheet detection sensors 20, 21, and 22 are input to the controller 25.
Each of the sheet detection sensors 20, 21, 22 detects the presence or absence of a sheet at each disposition position by using, for example, light reflection. As described above, the first to third chute guides 2 are provided. , 4a, 4b, 6a, 6b also function as detecting means for detecting the occurrence of a paper jam on the paper transport path formed by the paper feed path. The motor driver 26 drives the motor 8 in accordance with a control signal from the controller 25. In this configuration, the value of an applied current to the motor 8 is also set on the controller 25 side, and the motor driver 26 sends the motor 8 to the motor 8 based on the set conditions. A predetermined drive current is supplied. The controller 25
The setting of the applied current value on the side is determined by each paper detection sensor 2
It is configured to be performed based on detection signals from 0, 21 and 22.

Next, the operation of the paper transport device having the above-described configuration will be described. First, a basic operation in a situation where no paper jam (jam) occurs on the paper transport path will be described. First, the paper fed from the paper feed cassette is taken in between a pair of delivery rolls 1a and 1b, and is delivered according to the rotation of the delivery rolls 1a and 1b. The paper sent out in this manner is taken along the first chute guide 2 and taken away rolls 3a, 3a.
b. At this time, when the leading edge of the paper fed by the feed rolls 1a and 1b is detected by the paper detection sensor 22, a control signal is output from the controller 25 to the motor driver 26 starting from the detection timing, and the motor is driven in accordance with the control signal. A predetermined drive current is applied to the motor 8 from the driver 26.

As a result, the motor 8 starts, and at the same time, the motor gear 9 starts rotating. This motor gear 9
(The driving force of the motor 8) is transmitted to the driving gear 11 via the two-stage gear 10 meshing therewith, and further transmitted to the driving gear 13 via the idle gear 12. Thereby, the pair of take-away rolls 3a and 3b rotate, and at the same time, the pair of pre-registration rolls 5a and 5b.
b also rotates.

As described above, the take away rolls 3a, 3
When the leading edge of the sheet is taken in between the rolls in a state in which b is rotated, the sheet is thereafter taken away by the take-away roll 3.
a, 3b, the second chute guides 4a, 4b
b. Thereafter, the sheet is fed between the pair of pre-registration rolls 5a, 5b, and is conveyed along the third chute guides 6a, 6b according to the rotation of the pre-registration rolls 5a, 5b. And
When the leading edge of the sheet is detected by the sheet detection sensor 20, the solenoid 17 is excited according to a control signal from the controller 25. As a result, the plunger 18 of the solenoid 17 is retracted, and the pivot shaft 15 rotates by a predetermined angle due to the pivoting operation of the pivot member 16 interlocked with the retracting operation. With the rotation of the rotation shaft 15, the leading end of the gate member 14 advances into the sheet conveying path, and the leading end of the sheet is abutted against the gate member 14.

When the leading edge of the sheet is hit against the gate member 14 in this manner, the drive of the motor 8 is temporarily stopped after the pre-registration rolls 5a and 5b rotate for a predetermined time from that point. At this time, the outer peripheral sides of the third chute guides 6a and 6b are opened outward as shown by a dashed line in FIG. 1, whereby a curved portion is formed on the paper being conveyed.

Thereafter, at a predetermined timing corresponding to the timing of writing an image to the photosensitive drum 23, etc., the solenoid 1
7 is released, and the gate member 14 is retracted from the paper transport path in accordance with the release, and the registration rollers 7a, 7
The paper advances during b. The advance of the sheet in this case is performed by the bending force of the sheet itself. Next, the paper is transferred to the photosensitive drum 2 according to the rotation of the registration rolls 7a and 7b.
3 and the transfer device 24 (image transfer position), where the image is transferred from the photosensitive drum 23 to a sheet. Thereafter, the paper is conveyed one by one by repeating the same as described above, and the image is transferred to each paper.

Next, the operation when a paper jam occurs on the paper transport path will be described. First, the occurrence of a paper jam is determined by the controller 25 as described below based on the detection signals from the respective paper detection sensors 20, 21, 22 disposed at appropriate positions in the paper transport path as described above. .

That is, each of the sheet detection sensors 20, 21,
The timing at which the sheet 22 detects the leading edge or the trailing edge of the sheet is predetermined in accordance with the distance between the sensors, the speed of sheet transport by the roll, the size of the sheet to be transported, and the like. Therefore, for example, the pre-registration rolls 5a, 5
If a sheet jam occurs at an intermediate point of the sheet transport path from the position b to the registration rolls 7a and 7b, the sheet detection sensor 21 detects the leading edge of the sheet at a specified timing, but the downstream side of the sheet detection sensor 21 detects the leading end of the sheet. Since the paper detection sensor 20 cannot detect the leading edge of the paper even after the specified timing, the controller 25 determines that a paper jam has occurred on the paper conveyance path during that time. Similarly, take-away rolls 3a and 3b are moved to pre-registration rolls 5a and 5b.
If a paper jam occurs on the paper transport path leading to
Although the paper detection sensor 22 detects the leading edge of the paper at the specified timing, the paper detection sensor 21 on the downstream side cannot detect the leading edge of the paper even after the specified timing. It is determined that a paper jam has occurred on the paper transport path.

FIG. 3 is a timing chart showing a control mode of the motor, and FIG. 4 is a flowchart showing a control procedure when a paper jam (jam) occurs. First, in the flowchart of FIG. 4, the controller 25 determines whether or not a paper jam (jam) has occurred on the paper transport path based on the detection signals from the respective paper detection sensors 20, 21 and 22 as described above. If it is determined that a paper jam has occurred (step S1), the set value is changed so that the value of the current applied to the motor 8 becomes larger than in the steady state (step S2). As a result, as shown in FIG. 3, the drive current supplied to the motor 8 is increased from the steady-state A1 level to the A2 level after the jam detection timing T1.

At this time, the state of occurrence of paper jam is as follows.
For example, the paper fed between the photosensitive drum 23 and the transfer unit 24 is jammed by the registration rolls 7a and 7b, and the succeeding paper following this is taken away by the take-away rolls 3a and 3b.
b and the pre-registration rolls 5a and 5b are stopped at a position straddling the slide unit U, when the slide unit U is pulled out to remove the jammed paper, the succeeding paper is torn and the jam removal operation is performed. On the contrary, it becomes difficult.

Therefore, the controller 25 drives the motor 8 with the applied current value A2 larger than that in the steady state while monitoring the detection signal from the paper detection sensor 22, thereby straddling the slide unit U. Is fed to a predetermined position (step S).
3). The “predetermined position” in this case is a position that does not hinder the jam removal operation, and corresponds to a position where the succeeding paper fits in the slide unit U in the configuration example of FIG. 1.

When the succeeding paper collides with the preceding jammed paper at the time of feeding the paper, the conveyance resistance of the paper increases. In the present embodiment, the current applied to the motor 8 is detected at the time of detecting the jam (timing T1 in FIG. 3). Since the value is set to be larger than that in the steady state, the motor 8 does not step out even if the transport resistance increases due to the collision between the sheets. Therefore, the succeeding paper can be reliably fed to a predetermined position without using a large motor.

Thereafter, when the feeding of the succeeding paper is completed, the controller 25 determines at that time (at timing T in FIG. 3).
In step 2), the driving of the motor 8 is stopped (step S4). At this time, the timing for ending the feeding of the succeeding paper takes into consideration the time from when the paper detection sensor 22 detects the trailing edge of the succeeding paper to when the trailing edge of the paper completely passes through the takeaway rolls 3a and 3b. Is determined.

As described above, in this embodiment, when the occurrence of a paper jam (jam) is detected based on the detection signals from the respective paper detection sensors 20 to 22, the controller 25 applies the current applied to the motor 8 to the motor 8. The value is set to a value larger than that in the steady state, so that the paper located in the middle of the paper transport path is fed to a predetermined position.Therefore, even if a paper jam occurs in the above situation, The sheet conveyance operation stops in a state where the sheet is accommodated in the slide unit U. Therefore, even when the slide unit U is pulled out to remove the jammed paper, the paper is not broken. Controller 2
In 5, the current value applied to the motor 8 is set to be larger than that in the steady state only when a jam is detected, so that the power consumption of the motor 8 can be minimized.

In the above-described embodiment, the effectiveness in dealing with the case where the succeeding paper collides with the preceding jam paper has been described. However, in addition to this, for example, the paper is being conveyed by the pre-registration rolls 5a and 5b. Even if the paper is jammed and the trailing end of the jammed paper is protruding from the slide unit U, the value of the current applied to the motor 8 is set to be larger than that in the steady state as described above, so that the trailing edge of the jammed paper is The side can be reliably fed into the slide unit U.

When a paper jam occurs, the value of the current applied to the motor 8 may always be set to be larger than that in the normal state, regardless of the place where the paper jam occurs and the presence or absence of the succeeding paper. When a paper jam occurs, the position of the paper on the conveyance path is grasped based on the detection signals from the respective paper detection sensors 20 to 22, and if the position is a position that hinders the jam removal operation. Only in this case, the value of the current applied to the motor 8 may be set to be larger than that in the steady state, and the sheet may be fed to a predetermined position.

[0028]

As described above, according to the paper conveying apparatus of the present invention, when the occurrence of paper jam on the paper conveying path is detected by the detecting means, the control means drives the driving energy to the driving source of the paper conveying means. In this case, the sheet feeding means is set to be higher than that in the normal state, and the sheet conveying means is drive-controlled, so that the sheet being conveyed can be reliably fed to a predetermined position even if the conveyance resistance increases due to the collision between the sheets.
As a result, even if a large motor is not used, the conventional problem associated with feeding paper can be solved.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing an example of a mechanical configuration of a paper transport device to which the present invention is applied.

FIG. 2 is a block diagram illustrating a configuration example of a control system of the sheet conveying device according to the present invention.

FIG. 3 is a timing chart showing a control mode of a motor.

FIG. 4 is a flowchart illustrating a control procedure for occurrence of a paper jam.

[Explanation of symbols]

1a, 1b: delivery roll, 2: first shoot guide, 3a, 3b: take away roll, 4a, 4b ...
2nd chute guide, 5a, 5b ... pre-registration roll, 6a, 6b ... 3rd chute guide, 7a, 7b ...
Registration roll, 8 ... Motor, 20-22 ... Paper detection sensor, 25 ... Controller

Claims (1)

[Claims] A sheet conveyance unit configured to convey a sheet along a sheet conveyance path; a detection unit configured to detect occurrence of a paper jam on the paper conveyance path; and a case in which the occurrence of a paper jam is detected by the detection unit. In addition, the supply level of the driving energy to the drive source of the sheet conveying means is set to be larger than that in a normal state, and the driving of the sheet conveying means is controlled so as to feed the sheet located in the middle of the sheet conveying path to a predetermined position. A sheet transport device comprising a control unit.