JP2004029504A - Corona charger equipped with automatic wire take-up function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a corona discharger such that only a charge wire which deteriorates to become unusable is replaced by a simple mechanism as a means of replacing a charge wire when the charge wire deteriorates as a corona discharger which electrostatically charges a photoreceptor of an electrophotographic device. <P>SOLUTION: As shown in Fig. 1, one charge wire 4 is sent out of a sending-out reel 1, passed around an electrode reel 3 applied with voltage, and then wound around a take-up reel 2 to use the one wire as two upstream-side and downstream-side charge wires. When the wire is replaced, only an upstream-side charge wire 4a portion of the charge wire 4 is wound around the take-up reel 2, and consequently a portion used as a downstream-side wire 4b is arranged as the upstream-side charge wire 4a, while a new charge wire 4 is sent out of the sending-out reel 1. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a corona charger that performs non-contact charging using corona discharge as a charger for charging a photoconductor of an electrophotographic apparatus, and relates to a replacement when a charge wire used in the corona charger deteriorates. As a method, a corona charger having an automatic wire take-up function as an excellent wire exchange mechanism with a simple mechanism and economical is realized.
[0002]
[Prior art]
2. Description of the Related Art In an electrophotographic apparatus, an electrostatic latent image is formed on a photoconductor, a toner image is created by applying toner to the electrostatic latent image by an electric field, and printing is performed by transferring and fixing the toner image on a print medium. .
[0003]
The toner image forming process on the photoconductor is performed as follows. As shown in FIG. 5, the surface of the rotating photoconductor 50 is charged by a corona charger 52, and the printed image is optically exposed by an exposure device 55, thereby lowering the charged potential of the exposed portion, An electrostatic latent image is formed.
[0004]
Toner is attached to the electrostatic latent image by using the electric field force by the developing device 56 to form a toner image, which is transferred to the intermediate transfer member 51. The transferred toner image is then transferred and fixed to a print medium.
[0005]
The photoreceptor 50 to which the toner image has been transferred is initialized by removing residual toner with a cleaner blade 53 and discharging the surface with a discharging lamp 54, and one printing process is completed.
[0006]
In the printing process described above, a corona charger that performs non-contact charging using corona discharge has been used as a charger that charges a photoconductor in order to form an electrostatic latent image.
[0007]
The corona charger generates a corona discharge by applying a high voltage to the charge wire, thereby charging the surface of the photoconductor.
[0008]
The charge wire used in such a corona charger deteriorates due to adhesion of discharge products or erosion due to long-term discharge, making it difficult to discharge, causing uneven charging in the charging of the photoconductor surface. I do.
[0009]
In order to prevent such uneven charging, a corona charger provided with a plurality of charge wires and having improved charging ability has been devised. However, even when such a plurality of charge wires are provided, if they are used for a long period of time, they will eventually deteriorate due to discharge, and charge unevenness will occur.
[0010]
Further, a corona charger equipped with a mechanism for feeding out a new charge wire while winding up a deteriorated charge wire has been devised so that such charging unevenness does not occur.
[0011]
However, in such a method of using a plurality of charge wires and replacing them with new charge wires due to deterioration, conventionally, since all the plurality of charge wires are replaced with new ones, even the still usable charge wires are replaced. There was a problem of being uneconomical.
[0012]
[Problems to be solved by the invention]
As described above, the conventional technique has the following problems.
[0013]
In order to charge the photoreceptor of an electrophotographic apparatus, a high voltage is applied to a charge wire to generate a corona discharge. Deterioration due to discharge and difficulty in discharging sometimes caused uneven charging of the surface of the photoreceptor.
[0014]
In order to prevent such uneven charging, a corona charger using multiple charge wires has been devised in order to increase the charging ability. Occurred.
[0015]
Also, in order to prevent such charging unevenness, a corona charger equipped with a mechanism for sending out a new charge wire while winding up the deteriorated charge wire has been devised, but when a plurality of charge wires are used, Conventionally, when a charge wire is replaced due to deterioration, all of the charge wires are replaced with new ones, so that even a usable charge wire is replaced, which is uneconomical.
[0016]
An object of the present invention is to provide a corona charger using a plurality of charge wires for non-contact charging of a photoreceptor of an electrophotographic apparatus, as a means for replacing the charge wires when the charge wires are deteriorated by long-term discharge. An object of the present invention is to provide a corona charger that replaces only a charge wire that has deteriorated and can no longer be used.
[0017]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has taken the following measures.
[0018]
As shown in FIG. 1, one charge wire 4 is sent out from a feed reel 1 in a drive side case 6 provided at one end of a charger, and is fed into an electrode side case 8 provided at the other end of the charger. Is wound around the take-up reel 2 in the drive-side case 6 around the electrode reel 3 to which the above voltage is applied.
[0019]
As a result, one charge wire 4 is turned into an upstream charge wire 4a and a downstream charge wire 4b (the upstream charge wire is a portion of the photosensitive body to be charged immediately below the charger and is rotated. Sometimes, a wire on the side that comes directly above the portion first, and the downstream charge wire is a charge wire that comes on the side directly above the charged portion after the upstream side) As a result, the photosensitive member can be used for charging.
[0020]
When it is determined that the charging ability of the photoconductor is reduced due to the long-time discharge and the portion used for charging the charge wire 4 is deteriorated, the charge wire 4 is wound by the take-up reel 2 and a new charge wire is simultaneously discharged. The charge wire is sent out from the feed reel 1 and the charge wire is exchanged.
[0021]
As for the deterioration state of the charge wire 4 when the charging ability of the photoconductor is reduced, it is known that the deterioration of the charging wire 4a is more advanced in the upstream side. Mainly because of deterioration of the upstream charge wire 4a, the downstream charge wire 4b is still usable.
[0022]
Therefore, as a replacement of the charge wire 4, only the portion used as the upstream charge wire 4a is taken up by the take-up reel 2, whereby the portion used as the downstream charge wire 4b is replaced with the upstream charge wire 4a. , And at the same time, a new charge wire 4 is fed from the feed reel 1.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention has the following embodiments.
[0024]
As shown in FIG. 1, a supply reel 1 for feeding a new charge wire, a take-up reel 2 for winding a deteriorated charge wire, and an electrode reel 3 for applying a discharge voltage to the charge wire are provided. 2 so that the rotation amount and the rotation direction can be accurately controlled.
[0025]
As a result, one charge wire 4 can be used as two charge wires of the upstream charge wire 4a and the downstream charge wire 4b for charging the photosensitive member, and the charging ability can be improved. In addition, it is possible to freely determine which part of the charge wire 4 is to be used for the charging process by the feeding and winding operations of the feeding reel 1 and the winding reel 2.
[0026]
Also, when replacing the charge wire, only the upstream charge wire 4a can be wound up, and the downstream charge wire 4b can be disposed at the position of the upstream charge wire 4a for reuse.
[0027]
At the initial stage of deterioration of the charge wire, a cleaning member 5 for removing discharge products is provided. The cleaning member 5 is configured so as to sandwich the charge wire 4 at the position shown in the figure. As a cleaning operation, the charge wire 4 is moved by the rotation operation of the feed reel 1 and the take-up reel 2 and used for the charging process. By passing the cleaned portion through the cleaning member 5, the discharge products attached to the charge wire 4 are removed.
[0028]
This makes it possible to delay the deterioration of the charge wire by removing the adhesion of the discharge product to the charge wire, which causes the charge wire to be deteriorated by the discharge, at an early stage. Can be used.
[0029]
【Example】
A representative embodiment according to the present invention will be described. In the following, the same portions are denoted by the same reference numerals, and detailed description may be omitted.
[0030]
The present charging device is a non-contact type corona charging device that generates a corona discharge by applying a high voltage to a charge wire obtained by plating a tungsten wire with gold, thereby charging the surface of the photoconductor.
[0031]
As shown in FIG. 1, one charge wire 4 is sent out from a feed reel 1 in a drive side case 6 provided at one end of a charger, and is fed into an electrode side case 8 provided at the other end of the charger. Is wound around the take-up reel 2 in the drive side case 6 around the electrode reel 3 to which the above voltage is applied.
[0032]
With this configuration, when the surface of the photoconductor is charged, one charge wire 4 can be used as two charge wires of an upstream charge wire 4a and a downstream charge wire 4b. Capability is improved, and uneven charging is less likely to occur.
[0033]
As shown in FIG. 2, the electrode reel 3 is mounted on an electrode pedestal 13 that can move in the vertical direction in the figure, and this electrode pedestal 13 is urged by a pedestal spring 14 in the upward direction in the figure. Thus, the charge wire 4 applied to the electrode reel 3 is pulled to thereby prevent the charge wire 4 from sagging between the feed reel 1, the take-up reel 2 and the electrode reel 3.
[0034]
FIG. 2 shows a case in which a scorotron-type charger is used. The charge wire 4 is disposed in the shield 7, and the charging potential on the photoconductor surface is reduced by a grid mesh 15 connected to the grid electrode 16. Can be made variable by the voltage applied to.
[0035]
As shown in FIG. 2, the take-up reel 9 rotates the take-up reel drive gear 10 that drives the rotation axis of the take-up reel 2 to rotate the take-up reel 2 and the take-up reel 2. In addition, the take-up spur gear 11 on the same axis rotates, and the delivery spur gear 12 connected to the take-up spur gear 11 rotates, so that the delivery reel 1 also rotates at the same time.
[0036]
As shown in FIG. 3, the winding motor 9 is controlled by a winding control unit 17 so that the rotation direction and the rotation amount can be accurately controlled.
[0037]
By rotating the take-up motor 9, in the rotation direction shown in FIG. 3, the take-up spur gear 11 and the sending-out spur gear 12 are connected and rotated, thereby winding the take-up reel 2 as shown in the figure. When rotating in the take-up direction, the take-out reel 1 rotates in cooperation with the direction in which the new charge wire 4 is sent out, and the take-up motor 9 is rotated in the reverse direction so that the take-up reel 2 rotates in the direction in which the charge wire 4 is sent out. When doing so, the delivery reel 1 rotates in cooperation with the direction in which the charge wire 4 is wound up.
[0038]
When such rotation control by the winding motor 9 is deteriorated due to the long-term discharge of the charge wire 4, the winding control unit 17 performs the following processing by exchanging the charge wire. .
[0039]
When discharging of the charge wire 4 is started to charge the photoconductor, the discharge time is cumulatively added and stored in the winding control unit 17, and when a predetermined time is reached, the charge wire exchange mode is set. Then, only the portion of the charge wire 4 that has been used as the upstream charge wire 4 a in FIG. 1 is wound by the take-up reel 2 by rotating the winding motor 9.
[0040]
At this time, the portion used as the downstream charge wire 4b of the charge wire 4 at the same time is arranged at the position of the upstream charge wire 4a, and a new charge wire 4 is sent out by the sending reel 1, so that the downstream side is discharged. A new part of the charge wire 4 is arranged on the charge wire 4b. It should be noted that a new charge wire 4 of a sufficient amount necessary for replacement is wound on the delivery reel 1 as an initial state.
[0041]
By performing the replacement process of the charge wires 4 in this manner, only the upstream charge wires 4a with severe deterioration can be replaced, and the still usable downstream charge wires 4b can be used again as the upstream charge wires 4a. Very economical.
[0042]
In addition, even if charging unevenness occurs slightly due to deterioration of the portion reused on the upstream side, the downstream side at this time has been replaced with a new charge wire, and charging is performed by this downstream charge wire. Therefore, no uneven charging occurs on the surface of the photoconductor.
[0043]
As a condition for shifting to the exchange mode, a voltage applied to the charge wire 4 is measured instead of a discharge time, and when the voltage reaches a predetermined value or the potential of the photoconductor surface is measured by a surface voltmeter. The measurement may be configured to enter the exchange mode when the potential drops below a predetermined potential.
[0044]
As shown in FIG. 1, the present charger is provided with a cleaning member 5 for delaying the deterioration of the charge wire 4 due to discharge at an early stage.
[0045]
The winding control section 17 determines the initial stage of deterioration from values such as the charging time, the voltage applied to the charge wire, and the surface potential of the photoconductor, and automatically shifts to the cleaning mode.
[0046]
In the cleaning mode, the take-up motor 9 is rotated so that the portion of the upstream-side charge wire 4a shown in FIG. 1 is taken up by the take-up reel 2, so that the cleaning member 5 provided in the drive-side case 6 is moved upstream. The portion of the side charge wire 4a passes, and at this time, the discharge products attached to the wire are removed by the cleaning member 5.
[0047]
At the same time, the portion of the downstream-side charge wire 4b passes through the cleaning member 5 provided in the electrode-side case 8, and the discharge product attached to the wire is also removed by the cleaning member 5 here.
[0048]
When all the portions used for charging the charge wire 4 have passed through the cleaning member 5, the winding control unit 17 reversely rotates the winding motor 9 to return the charge wire 4 to the position before the shift to the cleaning mode, Exit the cleaning mode.
[0049]
The cleaning member 5 used here is configured such that a sponge-shaped member is sandwiched between the charge wires 4 as shown in FIG. By polishing the surface of the wire 4 so as to rub it, discharge products are removed.
[0050]
The above-described cleaning mode is performed at the initial stage of the deterioration of the charge wire 4 due to the discharge, and when the charging performance is not recovered even in such a cleaning mode, control is performed so as to shift to the exchange mode, thereby more effectively. The charge wire 4 can be used.
[0051]
【The invention's effect】
According to the present invention, the following effects can be expected.
[0052]
In order to charge the photoreceptor of an electrophotographic apparatus, a high voltage is applied to a charge wire to generate a corona discharge. Deterioration due to discharge and difficulty in discharging sometimes caused uneven charging of the surface of the photoreceptor.
[0053]
In order to prevent such uneven charging, a mechanism that uses a plurality of charge wires and sends out a new charge wire while winding up the deteriorated charge wire has been devised. Therefore, when the charge wire is replaced, all the charge wires are replaced with new ones, so that a charge wire that can still be used is replaced, which is uneconomical.
[0054]
By using the present invention, when the charging ability of the charger is reduced, a simple mechanism is used to replace only the severely deteriorated portion of the charge wire with a new one, and to reuse the still usable portion. , Can effectively use the charge wire.
[0055]
In addition, by automatically cleaning the charge wire in the initial stage of deterioration in the cleaning mode, the deterioration itself of the charge wire can be delayed, and the charge wire can be used more effectively.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of the present invention.
FIG. 2 is an explanatory view of an embodiment of the present invention.
FIG. 3 is a drawing illustrating a rotation control of a take-up reel and a delivery reel by a take-up motor.
FIG. 4 is a diagram illustrating a cleaning operation of a charge wire by a cleaning member.
FIG. 5 is an explanatory diagram of a toner image forming process on a photosensitive member.
[Explanation of symbols]
1: Delivery reel 2: Take-up reel 3: Electrode reel 4: Charge wire 4a: Upstream charge wire 4b: Downstream charge wire 5: Cleaning member 6: Driving case 7: Shield 8: Electrode case 9: Winding Motor 10: take-up reel drive gear 11: take-up spur gear 12: send-out spur gear 13: electrode pedestal 14: pedestal spring 15: grid mesh 16: grid electrode 17: take-up control unit

Claims (2)

In the process of forming an electrostatic latent image on the photoreceptor of an electrophotographic apparatus, a high voltage is applied to a charge wire to generate a corona discharge. ,
By sending one charge wire from one end of the charger and turning it back at the other end, it is possible to use multiple charge wires and to control the winding of the charge wire. Means for positioning the charge wire,
By the positioning means, when replacing the charge wire, arrange the charge wire used on the downstream side as the upstream charge wire,
A corona charger having an automatic wire winding function. In the process of forming an electrostatic latent image on the photoreceptor of an electrophotographic apparatus, a high voltage is applied to a charge wire to generate a corona discharge. ,
Including a cleaning member for cleaning the charge wire,
2. The corona charger according to claim 1, further comprising an automatic wire winding function.

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