JPH0668666B2 - Cleaning device for electrophotographic device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a developer for an object to be cleaned such as a photoconductor in an electrophotographic apparatus, which has a cleaning brush member that contacts the object to be cleaned and a scavenging roller that contacts the cleaning brush member. The present invention relates to a cleaning device that removes and collects.

2. Description of the Related Art As shown in FIG. the second is by the switch S _{1 1}
A cleaning device is known in which a power source E1 and a second power source E2 are switched and connected, and for example, a voltage of E1 = 150V is applied when cleaning an image portion and an E2 = 250V voltage is applied when cleaning a non-image portion. Is. Scavenging roller 3
A third power source E3 is connected to the terminal, and a voltage of, for example, 650V is applied.

In such a conventional cleaning device, if the applied voltage is not lower in the non-image portion than in the image portion, the carrier may adhere to the non-image portion or the cleaning property may change in the image portion, especially in the non-transfer portion. The image part and the non-image part are configured so that they can be switched and connected to different power sources by a switch.

A predetermined voltage is applied to the scavenging roller from another power source in consideration of the cleaning effect.

Therefore, when the applied voltage of the magnetic brush roller is switched between the image portion and the non-image portion, the potential difference between the magnetic brush roller and the scavenging roller is different between when cleaning the image portion and when cleaning the non-image portion. The amount of toner to be recovered also changes, and the toner concentration of the cleaning agent changes, so that the cleaning performance deteriorates.

In addition, there is a drawback in that the number of power sources is large, so that the cost becomes higher.

An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a cleaning device which eliminates a change in potential difference between a cleaning brush member such as a magnetic brush roller or a fur brush and a scavenging roller while moving toner. With the goal.

In order to achieve the above-mentioned object, the present invention makes it possible to switch the potential by allowing the cleaning brush member to be switchably connected to one electrode of one power source via two parallel electric circuits of different potentials. The scavenging roller is connected to the other electrode of the power source, and the scavenging roller and the cleaning brush member are electrically connected at a constant potential difference. A detailed description will be given below based on an embodiment of the present invention.

In FIG. 1, a cleaning brush member 2, for example, a magnetic brush roller 2 is arranged in contact with an object to be cleaned, for example, a photosensitive member 1. A fur brush having a low resistance such as carbon fiber may be used instead of the magnetic brush roller. A scavenging roller 3 is arranged in contact with the cleaning brush member 2. A collecting blade 5 is disposed in contact with the scavenging roller 3, and toner is collected from the scavenging roller 3. The toner collected by the collecting blade 5 is collected by the collecting spiral roller 4 and returned to the developing section.

The scavenging roller 3 is connected by a conductive wire 6 to an electrode plate 8 of a charging charger 7 that charges a member to be cleaned 1 such as a photosensitive member.

The discharge electrode of the charger 7 is connected to the high voltage power source E,
Part of the positive discharge electrode discharges to the surface of the photoconductor, for example, the Se photoconductor, to be charged with +800 V, and part of the positive electrode is the casing 9
, And a part is discharged to the electrode plate 8. The discharge current to the electrode plate 8 is applied to the scavenging roller 3 as a power source.

The scavenging roller 3 and the cleaning brush member 2 are connected by a conductive wire 10, with a Zener diode.
Z ₁ is connected in the middle of the lead wire 10, and 400 V is maintained between the scavenging roller 3 and the cleaning brush member 2 after a certain potential difference. Other electric elements may be used instead of the Zener diode Z _{1 as} long as they maintain a constant potential.

The cleaning brush member 2 has two electric circuits 1 arranged in parallel.
It is connected to 1, 12 through a lead wire 13. First electric circuit
The Zener diode Z ₂ is connected to 11 and the Zener diode Z ₃ is connected to the second electric circuit 12, and the first electric circuit 11 and the second electric circuit 12 can be switched and connected to the ground by the switch S 2. The casing 9 of the charging charger 7 is also connected to the ground.

One of the Zener diodes Z ₂ and Z ₃ , for example, Z ₂ is used for the image part, and the other Z ₃ is used for the non-image part.
Z ₂ is about 250V, selected so Z ₃ is about 150 V.

The switch S2 is connected to the first electric circuit 11 side when cleaning the image portion, and is connected to the second electric circuit 12 side when cleaning the non-image portion.

The voltage of Zener diode Z ₁ is about 400V to keep the concentration of cleaning agent on cleaning brush member 2 at 0.5wt%.
It is set to be constant. As a result, a certain amount of toner moves from the cleaning brush member 2 to the scavenging roller, and a constant cleaning density can always be maintained. When the concentration of the cleaning agent is low, the carrier of the cleaning agent cannot be electrostatically attached to the toner from the object to be cleaned, and when the concentration is high, the toner coverage on the carrier surface increases and cleaning cannot be performed in the same manner.

The Zener diode Z ₂ of the first electric circuit 11 is set to a voltage for 100% cleaning of the toner on the object to be cleaned 1, and if it is higher than that, leakage or danger to the human body increases. For example, select about 250V.

The Zener diode Z ₃ of the second electric circuit 12 does not adhere to the carrier, but applies a bias voltage such that the toner of 10.5 wt% of the cleaning agent is not developed on the member to be cleaned. For example, select about 150V.

The toner on the member to be cleaned 1 electrostatically adheres to the cleaning agent due to the potential difference between the cleaning brush member 2 and the member to be cleaned, for example, the photosensitive drum, and further, a constant amount between the scavenging roller 3 and the cleaning brush member 2. The bias causes a certain amount of toner to move to the scavenging roller 3 by electrostatic attachment.

The voltage applied to the cleaning brush member 2 can be changed to an appropriate value by switching between the first electric circuit 11 and the second electric circuit 12, and the potential difference between the scavenging roller 3 and the cleaning brush member 2 can be reduced. It can be kept constant at all times. Since the switch S2 is connected to the ground, the withstand voltage of the switch can be reduced.

Effect According to the present invention, the voltage can be applied as a common power source to the scavenging roller and the tarning brush member by using one power source and by using the charging charger of the photoconductor, so that the number of power sources can be reduced and the cost can be reduced. became.
Moreover, stable cleaning can be performed with a simple device, and even if the cleaning agent itself deteriorates, the cleaning can be performed with high reliability without deterioration.

That is, since a constant amount of toner is always collected by the scavenging roller, the cleaning performance does not deteriorate even if the scavenging roller always has a constant toner collecting capacity.

By using the same power source, the bias voltage can be easily switched without causing any problems in cleaning property, carrier adhesion and the like. In addition, the space can be reduced, and it has become possible to realize highly reliable functions with a small size and low cost.

[Brief description of drawings]

FIG. 1 is an illustration of cleaning according to the present invention, and FIG. 2 is an illustration of a conventional cleaning device. 1 ... Object to be cleaned 2 ... Cleaning brush member 3 ... Scavenging roller 7 ... Charging charger, 8 ... Electrode plate 11 ... First electric circuit, 12 ... Second electric circuit E ... Power supply, S2 ...... Switch Z ₁ , Z ₂ , Z ₃ ...... Zener diode

Claims (4)

[Claims] 1. A cleaning brush member in contact with an object to be cleaned, a scavenging roller in contact with the cleaning brush member, a voltage applying unit for applying a voltage to the cleaning brush member, and a pressure applied by the voltage applying unit is varied. A cleaning device in an electrophotographic apparatus, comprising: means and means for maintaining a constant voltage of the scavenging roller with respect to a voltage generated in the cleaning brush member by the applied voltage. 2. The voltage applying means comprises an image carrier charging charger, a high voltage power source for the charging charger, and an electrode plate in the charger for receiving a discharge current of the charger. A cleaning device in the electrophotographic apparatus according to claim 1. 3. The electrophotographic apparatus according to claim 1, wherein the means for varying the applied voltage comprises a plurality of Zener diodes connected to the cleaning brush means and a changeover switch. Cleaning device 4. A cleaning device in an electrophotographic apparatus according to claim 1, wherein the means for holding the voltage of the scavenging roller constant with respect to the voltage of the cleaning brush means is a Zener diode. .