JPS584166A - Removing device for unseparated transfer paper in copying machine - Google Patents

Abstract

PURPOSE:To simply remove unseparated transfer paper by fitting a paper winding sensor and an electric discharging charger along the surface of a photosensitive drum of a copying machine having a conductor separation belt. CONSTITUTION:Transfer paper 9 on which a toner image on a photosensitive drum 1 is transferred by a transfer charger 2 is separated from the drum by a conductor separation belt 5, but if miss separation is generated unfortunately, a paper winding sensor 10 detects it. Synchronously with the arrival of the leading end of the unseparated transfer paper to the discharging charger 11, electric discharging is started and the bias voltage between the transfer charger and the conductor belt 5 is released. If the distance between the transfer charger and the dischrging charger approximately coincides with that between the leading end A and the discharging charger (b), practically the transfer paper is completely discharged by discharging only the length of (b) from the leading end of the unseparated paper and discharging is stopped at the point of time, so that the transfer paper is easily removed by evacuating the separation belt.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention applies a bias voltage to a separation belt provided in contact with the photoreceptor after the toner image formed on the photoreceptor is transferred to transfer paper using a transfer charge. , relates to a non-separable transfer paper removing device for a copying machine which adsorbs the transferred transfer paper and conveys the transferred paper separately from a photoreceptor.

In a transfer-type electrophotographic copying machine, a toner image formed on a photoreceptor through a predetermined process is transferred to transfer paper fed from a paper feed unit by applying voltage to a transfer charger. Thereafter, this transfer paper is separated from the photoreceptor drum, conveyed to a fixing section, fixed thereon, and then discharged outside the machine.

Conventional methods for separating the transfer paper on which the toner image has been transferred from the photoreceptor include mechanical means such as a separation claw or a narrow separation belt installed in the conveyance path along the conveyance reference edge of the transfer paper, and negative pressure of air. methods have been adopted, such as a method of suction using a transfer charger, and a method of installing a separation charger immediately after the transfer charger and charging an AC voltage to separate it, but these methods do not damage the surface of the photoreceptor or damage the side of the copy There are drawbacks such as white spots occurring at the edges and unstable separation performance, and furthermore, it is necessary to provide a separate conveyance means to convey the separated transfer paper to the next process.

There is a conductor belt separation method that can improve these problems and perform both separation and conveyance. As shown in FIG. 1, an endless conductor separation belt 5 is wound around a pulley 6 and another pulley 4, which are provided next to the transfer charger 2 and close to the photoreceptor drum 1. A control power supply circuit 6 is connected to the control power supply circuit 6, which can switch the voltage between positive and negative or zero. Transfer paper 9 is fed from the paper feed section 7 to the transfer section between the photosensitive drum 1 and the transfer charger 2 by the register roller 8.
When the leading edge of the transfer paper 9 comes to the contact point A between the conductor separation belt 5 and the photoreceptor drum 1 after the toner is transferred under the voltage application of the transfer charger, the polarity is opposite to the transfer charge. By applying a bias voltage of 1 to the conductor separation belt 5, the leading edge of the transfer paper 9 is attracted to the conductor separation belt 5 and separated from the photoreceptor 1. The leading edge of the transfer paper is separated by the separation belt 5.
After the transfer charge is attracted, the control power supply circuit 6 switches the bias voltage to the same polarity as the transfer charge or to zero to ensure transfer. The thus attracted transfer paper is conveyed by the conductor belt 5 and reaches the fixing section.

Now, when a bias voltage with the opposite polarity to the transfer charge is applied to the above-mentioned conductive belt, the transfer paper is attracted to the belt, while some of the toner transferred onto the transfer paper returns to the surface of the photoconductor and transfers. The transfer rate decreases and defective transfer areas occur. Therefore, the voltage and application time of the reverse polarity bias applied to the conductor belt are kept at a level necessary for the leading edge of the transfer paper to separate from the photoreceptor and be attracted to the conductor belt. Therefore, a separation error sometimes occurs, and the transfer paper may wind around the photoreceptor drum.

Conventionally, as means for removing the transfer paper wrapped around the photoreceptor drum, a paper sensor is provided immediately after the contact point of the photoreceptor drum surface with the separation belt, and this sensor detects the wrapping of the transfer paper around the photoreceptor drum. Immediately after stopping the machine, the operator manually separated the separation belt from the photoreceptor drum and manually peeled off the transfer paper stuck to the photoreceptor drum due to electrostatic force. However, since the transfer paper is strongly electrostatically stuck to the photoreceptor drum, it is not only very difficult to remove it, but there is also the risk of damaging the photoreceptor surface with fingernails when removing the paper. Ta.

The present invention solves the above-mentioned drawbacks of the conventional non-separable transfer paper removal device in a copying machine having a conductor separation belt.
It is an object of the present invention to provide a device for removing non-separable transfer paper that is easy to remove and does not cause damage to the surface of a photoreceptor.

Hereinafter, the present invention will be explained in detail with reference to drawings showing embodiments thereof.

FIG. 2 shows an embodiment in which the present invention is applied to a copying machine having the conductor separation belt previously explained with reference to FIG. In this device, in addition to the configuration shown in FIG. 1, a paper-wrapped sensor 10. Further, a charger 11 for eliminating static electricity is provided immediately after that. Creepage distance from point A to sensor 10 is a
, when the creepage distance from point A to the charger 11 for static elimination is b, the transfer charge and bias voltage application to the conductor separation belt 5 are stopped at the same time as the sensor 10 detects the leading edge of the wrapped paper, and then the leading edge of the paper is static neutralized. charger 11
After the time required for the sheet to reach (that is, after the time required for the paper to travel the distance b - m), a voltage is applied to the static elimination charger 11 so that the paper is controlled to operate for the time required for the paper to travel the distance b. It has become.

Since this device is configured as described above, normally the transfer paper 9 fed by the registration rollers 8 is transferred to the separation belt after the toner image on the photoreceptor 1 is transferred under the application of voltage from the transfer charger 2. 5 and is separated and conveyed, peeled off from the separation belt 5 by a peeling claw 12, fixed by a fixing roller 16, and discharged outside the machine.

Now, if the transfer paper 9 that should be separated at point A unfortunately separates incorrectly, the transfer paper 9 will remain stuck to the photoreceptor drum 1 and will roll up with the rotation of the drum, and its leading edge will end at point A. When it moves by a distance a, it is detected by the paper wrapping sensor 10, and at the same time, the transfer charge and the application of the bias voltage to the conductor separation belt 5 are stopped.

The time required for the leading edge of the transfer paper to reach the charger 11 from this point, that is, the circumferential surface of the photoreceptor drum 1 is b-a
Only after the time it takes to rotate.

A voltage is applied to the static elimination charger 11, and room pressure continues to be applied for the time required for the circumferential surface of the photoreceptor drum 1 to move by a distance b. Therefore, when the leading edge of the non-separable transfer paper reaches the position of the static eliminating charger 11, the static eliminating charger 1
1 starts operating, and static electricity is removed from the tip in a range of approximately a length b.

At the same time as the leading edge of the transfer paper is detected by the sensor 10, the transfer charge and the bias voltage of the conductor separation belt 5 are released, so at this point, the portion of the transfer paper that was upstream of the transfer charger 2 is not charged. Only the area from the leading edge of the paper to the transfer charger is charged. In this embodiment, the length is approximately b, so that as described above, the charge in the area b from the leading edge of the paper is removed by the charger 11, and as a result, the charge on the transfer paper is substantially removed. Therefore, the operation of the static elimination charger 11 is stopped, the rotation of the photosensitive drum is stopped, and after the machine is stopped, the separation belt portions 3, 4.5
If the transfer charger 2 is retracted, no electrostatic force is acting between the photosensitive drum 1 and the transfer paper 9 at this time, so the transfer paper can be removed very easily.

In the above embodiment, as an example, the static elimination range by the static elimination charger 11 is equal to the distance from the contact point A of the photoreceptor drum and the conductive separation belt to the static elimination charger 11.
It goes without saying that the length is not necessarily limited to this, and it is sufficient to select an appropriate length that will substantially eliminate the charge on the transfer paper caused by the transfer charge and the separation belt.

Further, the operation of the static eliminating charger 11 may be started at any time after the sensor 1° detects the leading edge of the paper until it reaches the static eliminating charger 11, but from the point of view of saving power consumption, it is set as in the above embodiment. It is convenient.

As described above, according to the present invention, the non-separable transfer paper can be removed extremely easily, which not only improves work efficiency but also has the effect of preventing scratches on the circumferential surface of the photoreceptor drum.

[Brief explanation of drawings]

Figure 1 shows a copying machine with a conductor separation belt. FIG. 2 is a cross-sectional view schematically showing the vicinity of the separation portion, and FIG. 2 is a cross-sectional view showing an embodiment of the present invention. 1... Photoreceptor 2... Transfer charger 5
... Separation belt 9 ... Transfer paper 10 ... Paper-wrapped sensor 11 ... Static elimination charger No. 1:! 1 fJS2 diagram

Claims (1)

[Claims] After the toner image formed on the photoconductor is transferred to transfer paper using a transfer charge, a bias voltage is applied to a separation belt provided in contact with the photoconductor, and the transferred transfer paper is transferred to this. In a device for removing non-separable transfer paper of a copying machine which is adsorbed and conveyed separately from a photoreceptor, a paper wrapping sensor or the like is provided along the surface of the photoreceptor immediately after the point of contact with the separation belt.
Immediately after that, a static elimination charger is installed, and at the same time when the leading edge of the non-separable transfer paper is detected by the paper wrapping sensor, the transfer charge and the bias voltage application to the separation belt are canceled, and the paper wrapping sensor detects the transfer paper. A device for removing non-separable transfer paper, characterized in that the charger for static elimination is operated for a certain period of time after the leading edge of the transfer paper is detected.