JPH05132189A - Sheet transfer error detection device - Google Patents

Abstract

PURPOSE:To enable a sheet transfer error such as a sheet jam and exhaustion to be detected accurately and quickly, while keeping the high accuracy of transfer speed and printing. CONSTITUTION:This device is equipped with a free roller 18 in frictional contact with a sheet 3 and rotating under the carrying force thereof, and a speed detection mechanism 10 to detect the rotating speed of the free roller 18. In addition, a transfer error judgement means 11 is caused to make judgement as to whether there is any sheet transfer error, on the basis of pulse signals outputted from the speed detection mechanism 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper conveyance abnormality detecting device for surely and promptly detecting a paper conveyance abnormality such as paper jam or paper shortage in a printer or the like.

[0002]

2. Description of the Related Art FIG. 5 is a block diagram showing a conventional sheet feeding abnormality detecting device disclosed in, for example, Japanese Patent Laid-Open No. 13232038/1990, in which 1 and 2 are fixing rollers and 3 is a continuous form sheet ( (Hereinafter referred to as paper), 4 is a motor, 5 is a tension applying mechanism, 6 is a tension belt rotated by the motor 4, 7 is a protrusion on the tension belt 6 fitted into the passage hole of the paper 3, 8, 9 This tension belt 6
It is a pulley for passing around.

Further, 10 is a speed detecting mechanism for monitoring the conveyance speed of the paper 3, 11 is a conveyance abnormality judging means for executing a paper conveyance abnormality flow, 12 is a drive force of the motor 4 is transmitted to each part, and torque is controlled. A conveying clutch, 13 is an indicator for indicating that a conveyance abnormality has occurred, and 14 is an electric or mechanical element for which driving stop is requested when a conveyance abnormality occurs.

Next, the operation will be described. The fixing rollers 1 and 2 have a function of conveying the sheet 3 and a function of fixing the transfer image transferred onto the sheet 3, and are rotationally driven by the motor 4 via the conveying clutch 12.

The tension applying mechanism 5 fits a protrusion 7 of a tension belt 6 which is rotationally driven by a motor 4 into a through hole of the paper 3. The tension belt 6 is orbitally driven in the transport direction (direction of arrow A) at a speed slower than the transport speed of the paper 3 (for example, 50 mm / s), and during normal transport of the paper 3, the fixing roller 11, It is orbitally driven at a transport speed substantially equal to the transport speed of 12 (eg, 75 mm / s).

If a conveyance error occurs due to a paper jam, a paper break, or the like, the paper feed by the fixing rollers 1 and 2 is stopped and the paper is fed by the tension applying mechanism 5 only. , 2 to the conveyance speed of the tension applying mechanism 5.

On the other hand, the conveying speed is always the speed detecting mechanism 10.
Is detected, a signal is sent to the conveyance abnormality determination means 11, and when the speed is reduced, the conveyance abnormality determination means 11
Detects the conveyance abnormality and displays the conveyance abnormality on the display 13
And the drive of the electrical / mechanical element 14 which is requested to be stopped is stopped.

[0008]

Since the conventional paper conveyance abnormality detecting device is constructed as described above, the conveyance speed of the paper 3 is controlled via the clutch, and the tension applying mechanism 5 is connected to the paper 3. Therefore, there is a problem in that the speed is difficult to control and a transfer deviation occurs in the transfer portion.

The invention of claim 1 has been made to solve the above-mentioned problems, and it is possible to prevent the transfer deviation by maintaining the sheet conveying speed with high accuracy, and also when the conveying abnormality occurs, An object of the present invention is to provide a paper conveyance abnormality detection device that can reliably detect a paper conveyance abnormality such as a paper jam or a paper shortage without causing a transfer deviation.

It is another object of the present invention to provide a sheet conveyance abnormality detecting device capable of quickly detecting sheet conveyance abnormality.

[0011]

According to another aspect of the present invention, there is provided a paper conveyance abnormality detecting device, which has a paper conveyance mechanism for directly receiving a rotational force of a motor to convey a paper and frictionally contacting the paper. Free roller that rotates by receiving the conveying force of
A speed detection mechanism for detecting the rotation speed of the free roller is provided, and the transport abnormality determination means determines whether or not there is an abnormality in the sheet transport based on an output pulse of the speed detection mechanism.

According to another aspect of the present invention, there is provided a paper conveyance abnormality detecting device, wherein a paper conveyance mechanism for directly receiving the rotational force of a motor to convey the paper and frictionally contacting the paper and receiving the paper conveyance force. A free roller that rotates and a speed detection mechanism that detects the rotation speed of the free roller are provided. Based on the output pulse of the speed detection mechanism, the transportation abnormality determination means determines whether or not there is an abnormality in the sheet transportation, and The braking mechanism causes the free rotation of the free roller to be braked by friction.

[0013]

The free roller according to the invention of claim 1 is
Since the paper is frictionally contacted and is urged to rotate, if the paper is cut in the middle or loosened due to a paper jam, it will not rotate.

Further, the speed detection mechanism automatically detects the stop of the rotation or the abnormal decrease of the rotation speed, and the conveyance abnormality judging means judges that the sheet conveyance is abnormal on the basis of the detection output, and displays it on the display or the like. Display the anomaly.

The braking mechanism according to the invention of claim 2 is
By frictionally contacting the spring with the friction member of the free roller, the free rotation of the free roller when the paper runs out can be rapidly stopped, and the abnormality determination of the paper transportation can be speeded up.

[0016]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 3 is a continuous form sheet, 4 is a motor,
Reference numeral 5 is a tension applying mechanism, 6 is a tension belt rotatably driven by a motor 4, 7 is a protrusion on the tension belt 6 fitted into the passage hole of the paper 3, and 8 and 9 are for hanging the tension belt 6. It is a pulley.

Further, 10 is a speed detecting mechanism for monitoring the conveyance speed of the paper 3, 11 is a conveyance abnormality judging means for executing a paper conveyance abnormality flow, 12 is a driving force of the motor 4 to each part, and torque is controlled. A conveying clutch, 13 is an indicator for indicating that a conveyance abnormality has occurred, and 14 is an electric or mechanical element for which driving stop is requested when a conveyance abnormality occurs.

Further, 15 is a paper transport mechanism, and 16 and 17
Is a discharge roller for applying tension to the paper 3 and for putting the paper 3 into the storage space, 18 is a free roller that is rotated by a pressing force and a conveying force of the paper without power, and 19 is a transfer on the paper 3. A fixing device 20 for fixing an image is a printing process mechanism until a transfer image is formed on the sheet 3.

FIG. 2 shows the structure of the speed detecting mechanism,
Reference numeral 21 is a rotary plate having a plurality of slits 21a set on the rotary shaft of the free roller 18, and 22 is a sensor for outputting a pulse corresponding to the presence or absence of the slits 21a.

Next, the operation will be described. First, the sheet 3 on which the transfer image is formed by the printing process mechanism 20 is conveyed in the right direction (the direction of arrow B) by the sheet conveying mechanism 15, and the driving force of the motor 4 is directly transmitted to the tension belt 6 so that the constant speed is maintained. Keep A plurality of projections 7 are provided on the tension belt 6 at regular intervals in the rotation direction, and the projections 7 convey the paper 3 while fitting into the through holes of the paper 3.

The transferred image on the conveyed paper 3 is fixed by the flash fixing device 19 and discharged through the discharge rollers 16 and 17 to the paper storage space. The discharge rollers 16 and 17 receive the driving force of the motor 4 via the transport clutch 12, and a tension is applied to the discharge rollers 16 and 17 so that the torque does not cause the slack of the sheet 3.

In the course of the series of processes up to this point, the free roller 18 does not have its own power, but receives a predetermined pressing force of the sheet 3 due to the conveying force of the sheet 3 and the tension of the discharge rollers 16 and 17. It rotates at the transport speed (surface speed) of.

When a conveyance error occurs due to a paper jam, a paper shortage, or the like, the conveyance of the paper on the free roller 18 is stopped or the paper runs out, so the free roller 18 stops rotating. Therefore, this stopped state is detected by the speed detection mechanism 10, and the detection output is sent to the conveyance abnormality determination means 11. That is, the speed detecting mechanism 10 includes the rotating plate 21 having the slit 21a shown in FIG.
When the rotary plate 20 rotates together with the free roller 18, it outputs a pulsed signal according to the presence or absence of the slit 21a.

Therefore, when the pulse-like signal disappears due to the stop of the sheet conveyance or the pulse interval T1 and the pulse period T2 as shown in FIG. It is determined that the conveyance of the paper 3 is abnormal, and the display 1 indicates that the conveyance is abnormal.
3 is displayed, and the driving of the electric / mechanical element 14 for which driving stop is requested is stopped.

Example 2. FIG. 4 shows an embodiment of the invention of claim 2. As for this, 23 is a resin-made friction ring attached to the rotary shaft of the free roller 18, 24 is a spring which makes elastic contact with the friction ring 23 and gives friction to the rotation of the free roller 18, 2
Reference numerals 5 and 26 are support pins for fixing both ends of the spring 24. The friction ring 23 and the spring 24 form a braking mechanism 27 for free roller rotation.

In the braking mechanism 27, when the paper runs out or the paper jam occurs, the spring 24 comes into contact with the friction ring 23 to obtain an appropriate friction, so that the free roller 18 freely rotates due to inertia. Therefore, there is an advantage that the abnormality detection can be speeded up by quick deceleration and stop.

In the above embodiment, the flash fixing is applied to the printer. However, other fixing methods such as a heat fixing roller may be used, and the same effect as that of the above embodiment can be obtained.

[0028]

As described above, according to the first aspect of the present invention, the sheet conveying mechanism for directly receiving the rotational force of the motor to convey the sheet, and the sheet conveying mechanism that makes frictional contact with the sheet to reduce the sheet conveying force. A free roller that receives and rotates, and a speed detection mechanism that detects the rotation speed of the free roller are provided, and based on the output pulse of the speed detection mechanism, the transportation abnormality determination means determines whether or not there is an abnormality in the sheet transportation. With this configuration, it is possible to obtain the one that can accurately detect the conveyance abnormality such as the paper jam or the paper shortage while keeping the conveyance speed of the sheet with high accuracy.

Further, according to the invention of claim 2, since the free rotation of the free roller is limited by the braking mechanism, there is an effect that it is possible to speed up the detection of a paper conveyance abnormality.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a sheet conveyance abnormality detection device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a rotation speed detection mechanism in FIG.

FIG. 3 is a waveform diagram showing an output signal of the rotation speed detection mechanism in FIG.

FIG. 4 is a perspective view showing a main part of a sheet transport abnormality detecting device according to an embodiment of the invention of claim 2;

FIG. 5 is a configuration diagram showing a conventional sheet conveyance abnormality detection device.

[Explanation of symbols]

 3 Paper 4 Motor 10 Speed Detection Mechanism 11 Transport Abnormality Determining Means 15 Paper Transport Mechanism 18 Free Roller 27 Braking Mechanism

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H04N 1/31 9186-5C

Claims (2)

[Claims] 1. A paper conveyance mechanism for directly receiving a rotational force of a motor to convey a sheet, a free roller that comes into frictional contact with the sheet and rotates by the conveyance force of the sheet, and a rotation speed of the free roller. A paper conveyance abnormality detection device comprising a speed detection mechanism for detecting, and a conveyance abnormality judging means for judging whether or not there is a paper conveyance abnormality based on an output pulse of the speed detection mechanism. 2. A sheet conveying mechanism for directly receiving a rotational force of a motor to convey a sheet, a free roller that is in frictional contact with the sheet and rotates by receiving the sheet conveying force, and a rotational speed of the free roller. A speed detecting mechanism for detecting, a conveyance abnormality judging means for judging whether or not there is an abnormality in the sheet conveyance based on an output pulse of the speed detecting mechanism, and a braking mechanism for braking the free rotation of the free roller by friction. Paper conveyance abnormality detection device.