JPH11249393A - Corona generator cleaning mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic cleaning mechanism for a corona generator which securely cleans the wire of the corona generator of an electrophotographic device. SOLUTION: The mechanism is composed such that a piece 11 to be detected is attached to a gear 10 which rotates linked with a helical shaft 7 moving a cleaning member 4 and the piece 11 to be detected obstructs a detector 5A. The position of the cleaning member 4 is judged from a signal from the detector 5A and control is executed. The detector 5A and a motor 8 are mounted on the main body of the electrophotographic device separately from a corona generator unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning mechanism for a corona generating device in an electrophotographic apparatus which electrostatically charges, transfers, removes electricity, etc., facing a photoreceptor.

[0002]

2. Description of the Related Art In recent years, in an electrophotographic apparatus, in order to reduce the cost of a printing apparatus, a pre-cut printing medium is used in place of a continuous printing medium to save labor in a cutting operation after printing, or to reduce a printing medium. By performing printing on both sides, the amount of print media used has been reduced. This has led to environmental protection by reducing mass consumption and mass disposal of consumables such as print media, and has recently attracted attention.

[0003] On the other hand, the operators of the electrophotographic apparatus have changed from a specific operator trained as in the past to an unspecified number of uneducated operators.
The operation related to cleaning of an apparatus, which has been an item related to maintenance, has been automated. Under such circumstances, the cleaning of the corona generating device which is easily contaminated with toner or paper powder used in the device has been automated.

FIG. 3 shows an example of a conventional cleaning mechanism of a corona generating device, wherein (a) is a plan view of a corona generating device unit,
(B) is a longitudinal sectional view of the cleaning mechanism including the corona generating device unit. The shield plate 1 of the corona generator is provided with a shield groove 2 in which a wire 3 for corona discharge is stretched. The cleaning member 4 is fitted into the shield groove 2 so that the tip thereof contacts the wire 3, and can be moved by a driving mechanism described below while being guided by the shield groove 2.

[0005] That is, the cleaning member 4 is provided with a hole formed by cutting a spiral groove. The spiral shaft 7 passes through the hole, and both ends of the spiral shaft 7 are supported by the holding members 6.

The helical shaft 7 has a structure in which it can freely rotate in a hole provided in the holding member 6. One side of the helical shaft 7 is connected to a motor 8 via a gear 9. A small and inexpensive DC brush motor is usually used for the motor.

When the motor 8 rotates, the helical shaft 7
Also rotates, and the cleaning member 4 moves on the spiral shaft 7. Nylon bristle or the like is implanted in the contact portion between the cleaning member 4 and the wire 3, and the bristle moves while rubbing the wire 3 to clean the wire 3.

The detector 5 detects that the cleaning member 4 is at a predetermined position. In this embodiment, the detector 5 is arranged near one end (A end) of the spiral shaft 7. Detector 5
Has a structure that is directly turned on / off by the cleaning member 4 using, for example, a microswitch or the like. When the cleaning member 4 is at the end A of the helical shaft 7, the signal of the detector 5 is logic "1". Becomes

Next, the operation of the above-mentioned automatic cleaning mechanism will be described with reference to the timing charts of FIGS. First, the cleaning member 4 is at the end A shown in FIG. 3, and at this time, the signal of the detector 5 is at logic "1".

When cleaning the wire 3, the drive signal of the motor 8 is set to logic "1" as shown in FIG. 4, and when the motor 8 is driven, the cleaning member 4 starts to move toward the end B in FIG. In this case, the logic of the rotation direction switching signal is “0”.

When the cleaning member 4 leaves the detector 5, the signal from the detector 5 changes to logic "0". Assuming that a normal time from when the drive signal of the motor 8 becomes logic "1" to when the signal of the detector 5 becomes logic "0" is, for example, t1,
If the signal of the detector 5 remains at logic "1" even after the time t1 has elapsed since the drive of the motor 8, it is determined that the cleaning member 4 has not moved for some reason.
Report an error to the host controller.

When it is determined that there is no abnormality described above,
For example, when the time t2 elapses after the signal of the detector 5 becomes logic "0", it is determined by this time determination that the cleaning member 4 has reached the end B of the shield groove 2. Here, the rotation direction switching signal of the motor 8 is set to the logic "1" which is the reverse of the previous one.
Thus, the cleaning member 4 is moved in the direction A. When the cleaning member 4 reaches the end A, the detector 5 becomes logic "1". Therefore, the drive signal of the motor 8 is set to logic "0", the rotation of the motor 8 is stopped, and the cleaning operation of the wire 3 ends. . If the signal of the detector 5 does not become logic "1" even after the time t3 has elapsed since the switching of the rotation direction switching signal of the motor 8, it is regarded as abnormal.

[0013]

The conventional cleaning mechanism of a corona generator has the following problems to be improved.

(1) After detecting the initial position of the cleaning member, it waits for the cleaning member to operate for a certain period of time (for example, time t2 in FIG. 4), and determines that the cleaning member has reached the opposite side. Therefore, if the amount of movement of the cleaning member per unit time changes due to contamination of the cleaning member, the entire wire 3 cannot be reliably cleaned.

(2) Detector and motor (cleaning member drive source)
And the like are contained in the same casing of the corona generator unit, it is necessary to remove a cable or a connector connecting the corona generator and the electrophotographic apparatus when removing the corona generator.

(3) When the corona generator is used as a replacement part, conventionally, the motor and the sensor of the cleaning mechanism are included in the corona generator unit. Therefore, these motors and detectors are also replaced together with the corona generator. The cost of replacement parts.

(4) When an abnormal situation such as the cleaning member being locked halfway occurs, it is determined whether or not the cleaning member is locked, after the initial position sensor logic becomes "0" and the logic becomes "1" again. (T2 + t3 in FIG. 4)
In the meantime, the motor may be continuously locked, etc., and the worst case may be smoke and burnout of the motor.

An object of the present invention is to solve the above problems,
An object of the present invention is to provide a highly reliable automatic cleaning mechanism for a corona generating device that operates stably.

[0019]

The present invention is configured as follows to solve the above-mentioned problems.

One is a mechanism for cleaning a corona generator of an electrophotographic apparatus, comprising a cleaning member, a helical shaft for driving the cleaning member, and a motor for driving the helical shaft. In the cleaning mechanism, a detector for detecting the number of rotations of the spiral shaft is provided (first problem solving means).

One is a mechanism for cleaning the corona generating device of the electrophotographic apparatus, a cleaning member, a spiral shaft for driving the cleaning member, a motor for driving the spiral shaft, and a position of the cleaning member. And a detector for detecting the corona generation, wherein the detector and the motor of the cleaning mechanism are installed in the main body of the electrophotographic apparatus separately from the unit of the corona generation device, and the corona generation is performed. A device unit is configured to be detachable independently of the detector and the motor (second problem solving means).

One is that when the power is turned on to the electrophotographic apparatus, the helical shaft is rotated in a predetermined direction, and from this rotation, the initial position of the cleaning member is set using the detector (third). Means for solving problems).

One is that in the corona generating device cleaning mechanism described in the first and second means for solving the problems, after the helical shaft is driven, a signal from the detector is detected at a constant period. In the case where the cleaning member has run out, a setting is made to notify the controller of the electrophotographic apparatus of an abnormality by comparing the cleaning member with the current position (fourth problem solving means).

[0024]

1 shows an embodiment of a corona generator cleaning mechanism according to the present invention. FIG. 1 (a) is a plan view of a corona generator unit, and FIG. 1 (b) is a cleaning including the corona generator unit. It is a longitudinal section of a mechanism.

In FIG. 1, a shield plate 1, a shield groove 2, a wire for corona discharge 3, a cleaning member 4, and a holding member 6
Is similar to that of the conventional example of FIG. 3 described above, and a description thereof will be omitted.

The corona generating device includes a wire 3, a shield plate 1, a cleaning member 4, a spiral shaft 7, and a holding member 6
The detector 5A and the drive motor 8 of the cleaning member, which will be described later, are installed in the main body part 12 of the electrophotographic apparatus separately from the corona generator unit.

One end of the helical shaft 7 is one shaft holding member 6 (in this example, the shaft holding member on the A end side).
Is extended toward the motor 8 installation side from the position. The corona generator unit is set in the main body of the electrophotographic apparatus by being pushed in the direction of the motor 8 along a guide (not shown). On the other hand, a gear 9 is attached to the motor 8 so that when the corona generating device unit is set in the main body of the electrophotographic apparatus, the extended portion of the helical shaft 7 is engaged with the gear 9. ing. Also,
At this time, the helical shaft 7 also engages with the gear 10 which is an element of the detector 11.

Therefore, when the motor 8 is rotated in this state, the helical shaft 7 is rotated via the gear 9 and the gear 10 is further rotated. As the helical shaft 7 rotates, the cleaning member 4 moves to clean the wire 3.

As the detector 5A, for example, a blocking type optical sensor such as a photo interrupter is used. As the spiral shaft 7 rotates, the gear 10 also rotates. Gear 1
The detection piece 11 is attached to 0, and when the gear 10 rotates, the detection piece 11 blocks the detector 5A at a constant cycle. In this example, when the detected piece 11 blocks the detector 5A, a logic “1” pulse is output from the detector 5A, and the detected piece 1
If 1 does not block the detector 5A, the signal from the detector 5A is assumed to be logic "0".

Next, the operation of the automatic cleaning mechanism of the present embodiment will be described with reference to the configuration of FIG. 1 and the time chart of FIG.

First, the operation of setting the initial position of the cleaning member 4 will be described.

When the corona cleaning mechanism is set in the main body of the electrophotographic apparatus, it is basically unclear at which position the cleaning member 4 is located on the spiral shaft 7 at first.

For example, when the corona cleaning mechanism is set in the main body of the electrophotographic apparatus, it is assumed that the cleaning member 4 is at the position C in FIG. As shown in FIG. 2A, after the power of the electrophotographic apparatus is turned on, first, the drive signal of the motor 8 is changed to logic "1".
Then, the cleaning member 4 is moved in the direction of the end A in FIG. When the helical shaft 7 rotates, the signal from the detector 5A becomes logic "1" at a certain time t2. The signal from the detector 5A is monitored by, for example, a timer IC or the like.
From time t2 after the signal from
When the cleaning member 4 does not reach the logic "0" again after 3 elapses, it is determined that the cleaning member 4 has reached the end A in FIG. 1, the drive signal of the motor 8 is set to the logic "0", and the initial position setting operation is completed. I do. Such initial position setting is performed when the power of the electrophotographic apparatus is turned on by rotating the helical shaft in a predetermined direction.
A can be set.

Next, the cleaning operation will be described. The drive signal is set to logic "1", and the cleaning member 4 is moved toward the end B in FIG. The time t1 from when the drive signal is changed to logic "1" to when the signal of the detector 5A becomes logic "1" must be shorter than the time t2 required for the helical shaft 7 to make one rotation. Here, when the time t1 is, for example, 1.5 times the time t2, it is determined to be abnormal.

When the cleaning member 4 is normally moving in the direction of the end B, the output from the detector 5A repeats logic "1" and "0" at a constant cycle t2. If the number of times that the pulse output from the detector 5A becomes logic "1" is counted, it is known from the reduction ratio of the spiral shaft 7 and the gear 11 what rotation the spiral shaft 7 is currently rotating. I can do it.
In this example, the reduction ratios of the spiral shaft 7, the gear 9, and the gear 10 are all one-to-one. As an example, as shown in FIG. 2B, when the spiral shaft 7 rotates five times, the cleaning member 4 is rotated.
Reaches the end B, the output from the detector 5A remains at the logic "1" or the logic "0" after the logic "1" has been output five times, that is, the pulse having the period t2 has been generated five times.
The output from the detector 5A does not change even after the time t2 has elapsed. At this time, it is determined that the cleaning member 4 has reached the end B, the switching signal of the rotation direction of the motor 8 is set to logic "1", and the cleaning member 4 is moved toward the end A. Thereafter, after the output of the detector 5A becomes logic "1" five times (after five pulses of the period t2 are generated five times), the signal logic "0" after t2 does not change as before. At this point, it is determined that the cleaning member 4 has reached the end A, and the driving signal of the motor 8 is set to logic "0" to end the cleaning operation.

Also, after driving the helical shaft 7, the signal "1" from the detector at a fixed period t2 at an intermediate position (before the output of the detector 5A does not become logic "1" five times).
Is set to notify the controller of the electrophotographic apparatus of abnormality by comparing the current position of the cleaning member with the current position of the cleaning member.

[0037]

As described in detail in the above embodiment, according to the first means for solving the problems of the present invention, by directly detecting the rotation state of the helical shaft, the locking of the cleaning member or the like is performed based on the detection signal. Can be detected in the entire moving range of the cleaning member. Therefore, it is possible to reliably detect an abnormality such as the cleaning member being locked due to dirt or the like.

According to the second means for solving the problems, the unit of the corona generator is separated from the motor and the detector of the cleaning mechanism so that the corona generator can be replaced independently of the motor and the detector. The connector can be removed at the time of replacement of the corona generating device, and the workability of replacing the corona generating device can be greatly improved. Further, the cost as a replacement part of the corona generating device can be significantly reduced.

According to the third means for solving the problems, the cleaning member is always moved to a predetermined position after the power of the electrophotographic apparatus is turned on, so that cleaning due to the improper position of the cleaning member is performed. Problems such as defects can be reliably prevented.

According to the fifth means for solving the problems, the movement of the cleaning member is determined based on the output cycle of the detector. Therefore, when the cleaning member is locked due to dirt or the like, the abnormality can be detected in a minimum time. Can be detected.

[Brief description of the drawings]

FIG. 1 is a plan view of a corona generator unit according to an embodiment of the present invention; FIG.
(B) is a longitudinal sectional view of a cleaning mechanism including the corona generating device unit.

FIG. 2 is a timing chart for explaining the operation of the corona generator cleaning mechanism according to the embodiment.

FIG. 3 is an example of a conventional corona generating device cleaning mechanism.
(A) is a plan view of a corona generator unit, and (b) is a longitudinal sectional view of a cleaning mechanism including the corona generator unit.

FIG. 4 is a timing chart for explaining the operation of the conventional corona generating device cleaning mechanism.

[Explanation of symbols]

4 cleaning member, 5A detector, 7 helical shaft, 8
... Motor, 9 ... Gear, 10 ... Gear, 11 ... Detected piece.

Claims (5)

[Claims] 1. A mechanism for cleaning a corona generator of an electrophotographic apparatus, comprising: a cleaning member; a helical shaft for driving the cleaning member; and a motor for driving the helical shaft. 3. The corona generator cleaning mechanism according to claim 1, further comprising a detector for detecting the number of times the spiral shaft has rotated. 2. A mechanism for cleaning a corona generating device of an electrophotographic apparatus, comprising: a cleaning member; a helical shaft driving the cleaning member; a motor driving the helical shaft;
A corona generating device cleaning mechanism including a detector for detecting a position of the cleaning member, wherein the detector and the motor of the cleaning mechanism are installed in the electrophotographic apparatus main body separately from the corona generating device unit. A unit of the corona generator can be detached independently of the detector and the motor; 3. The corona generating device cleaning mechanism according to claim 1, wherein the detector is configured to count the number of rotations of the helical shaft to detect a current position of the cleaning member. 4. When the power of the electrophotographic apparatus is turned on, the helical shaft is rotated in a predetermined direction, and an initial position of the cleaning member is set from the rotation by using the detector. The corona generating device cleaning mechanism according to claim 2 or 3. 5. After the driving of the helical shaft, if a signal from the detector is not detected at a constant period, the controller of the electrophotographic apparatus is abnormal by comparing the signal with the current position of the cleaning member. The corona generating device cleaning mechanism according to any one of claims 1 to 4, wherein the corona generating device cleaning mechanism is set to give a notification.