JPH06161222A - Image forming device - Google Patents

Abstract

PURPOSE:To efficiently clean an electrifying wire by performing the detection of white stripe to a transfer paper on which a reference original is transferred, thereby detecting the staining position of the electrifying wire based on the detected result. CONSTITUTION:The original image corresponding to the reference original 17 is transferred on the transfer paper and housed in an intermediate tray 35. When the white stripe is detected by the white stripe sensor of a white stripe detecting device G, a detection signal is outputted to a CPU. The CPU calculates a distance from a detection reference position to a white stripe detection position based on the number of pulses of a motor for driving a sensor in accordance with the white stripe detection signal. Then, the moving amount of a cleaning body 63 to the staining position of the electrifying wire 55 in an electrifying device 19 is calculated. When the detection of the white stripe is finished, the CPU drives a cleaning body driving motor so as to start the going-motion of the cleaning body 63. Just before or when the cleaning body 63 attains the calculated moving amount, the CPU controls and drives the cleaning body 63 to perform the specified reciprocation previously set.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for detecting a stain on a charging wire by detecting a white line on a transfer sheet and cleaning the charging wire.

[0002]

2. Description of the Related Art Generally, in an image forming apparatus such as a copying machine, the residual toner on the surface of the photosensitive drum is scattered without being completely removed by a cleaning apparatus, and dust or dust that has entered the image forming apparatus is generated. The paper dust of the transfer paper may adhere to the charging wire. In such a case, the charging device cannot apply the required voltage to the photosensitive drum, and the transfer image has a white streak in the sub-scanning direction. There was an inconvenience. Conventionally, in such a case, the charging device has been detached from the image forming apparatus, and the portion of the transfer paper corresponding to the portion where the white streak has occurred is carefully cleaned. However, such work is very complicated. Therefore, recently, a cleaning pad for cleaning the charging wire is provided in the charging device, and the cleaning pad slides along the charging wire to clean dirt such as toner and paper dust adhering to the charging wire. An image forming apparatus provided with a wire cleaning mechanism has been proposed.

[0003]

In the image forming apparatus provided with the cleaning mechanism for the charging wire as described above, in general, the time from when the copying machine is started by turning on the main switch to when the copying machine becomes stable (copying is possible). Time to become)
Is used to clean the charging wire, and at this time, the cleaning pad is set to reciprocate once at a constant speed while slidingly contacting the charging wire in the main scanning direction. However, it is difficult to completely clean the dirt such as adhered toner by simply moving the cleaning pad back and forth once at a constant speed in the main scanning direction. Therefore, for example, it is conceivable to set it so as to reciprocate a plurality of times, but in this case, there is a concern that the cleaning time will increase or the cleaning pad will deteriorate due to wear, and thus it cannot be said that the cleaning method is efficient.

The present invention has been made in order to solve the above problems, and detects white stripes on a transfer paper on which a reference original is transferred, and detects the dirty position of the charging wire based on the detection result. However, it is an object of the present invention to provide an image forming apparatus capable of efficiently cleaning the charging wire.

[0005]

The invention according to claim 1 is
In an image forming apparatus that guides an image of a reference document read by an optical system onto a photoconductor charged to a predetermined potential by a charging device to form a latent image, and further forms a toner image and transfers the latent image to a transfer sheet. A cleaning member that is slidable along the charging wire of the charging device, a driving unit that allows the cleaning member to reciprocate between both sides of the charging wire, and a transfer paper on which the image of the reference document is transferred. Detecting means for detecting white stripes in the image over at least one line in the main scanning direction, storage means for storing the white stripe detection position detected by the detecting means, and the cleaning member up to the stored white stripe position And a cleaning control means for controlling the drive means so as to perform a predetermined cleaning operation at the white streak position.

According to a second aspect of the present invention, the cleaning control means controls the driving means so as to reciprocate the white streak position a plurality of times.

According to a third aspect of the present invention, the cleaning control means controls the driving means so as to reduce the sliding speed with respect to the white streak position.

According to a fourth aspect of the present invention, in the image forming apparatus according to the first aspect, the optical system is capable of reciprocating movement, and a document placing plate surface arranged within the range is set as a sub-scanning range. On the other hand, the reference document is arranged at a position within the reciprocating range and outside the sub-scanning range,
The lower surface is formed on the lower surface of a member flush with the document mounting surface, and the optical system is stopped under this member when reading the reference document.

According to a fifth aspect of the invention, in the image forming apparatus according to the first aspect, there is provided a sheet re-feeding path for reversing the transfer sheet on which the reference document is transferred and re-feeding the sheet again to the photoconductor. When the cleaning means cleans the charging wire based on the detection of the white streaks on the transfer paper, the transfer paper is re-fed from the re-feed path to the photoconductor, and again after the transfer, the re-feed path. And a sheet re-feeding control unit for leading the sheet.

According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect, when the re-feeding control means guides the transfer sheet to the re-feeding path, the detecting means detects the previous white line. The presence or absence of white stripes is detected only for the position.

[0011]

According to the first aspect of the present invention, the white streaks in the main scanning direction of the transfer paper on which the reference original image is copied are detected by the detecting means. The position of the white stripe is stored, and the driving means slides the cleaning member along the charging wire to perform a predetermined cleaning operation set in advance at the white stripe detection position.

According to the second aspect of the present invention, the cleaning member performs cleaning by sliding the white stripe position back and forth a plurality of times.

According to the third aspect of the invention, the cleaning member cleans by reducing the sliding speed at the white streak position.

According to the fourth aspect of the present invention, when the white stripe is detected, the scanning optical system is stopped below the reference original formed outside the surface of the original placing plate to read the reference original. , Make a copy on transfer paper.

According to the fifth aspect of the present invention, when the charging wire is cleaned based on the detection of the white line on the transfer sheet, the transfer sheet is re-fed and the reference original image is transferred. Done. Then, this transfer paper is guided again to the re-feeding path, and the white stripe is confirmed and detected by the detecting means.

According to the sixth aspect of the invention, when confirming and detecting the presence or absence of the white stripe, the detecting means detects only the position where the white stripe was previously detected.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An image forming apparatus (copier) of the present invention will be described with reference to the drawings. FIG. 1 is an overall configuration diagram showing an example of the copying machine of the present invention.

In FIG. 1, the copying machine 1 is provided with a contact glass 2 as a document placing plate on the upper surface thereof and an automatic document feeder 3 for automatically conveying and discharging a copied document on the contact glass 2. The inside thereof is provided with an optical mechanism L, an image forming means P, a reversing device K, a sheet re-feeding mechanism R, and a sheet conveying mechanism for feeding and conveying a transfer sheet, which constitutes the basic configuration.

The optical mechanism L comprises a halogen lamp 4, a first optical system 11 including reflecting mirrors 5 and 6, a second optical system 12 including reflecting mirrors 7 and 8, a reflecting mirror 9 and an imaging lens 10. ing. An optical system drive motor 13 is arranged substantially at the center of the optical mechanism L, and the first optical system 11 and the second optical system 12 are required by driving the optical system drive motor 13. The document is reciprocally moved at intervals so that the image of the original is projected onto the image forming means P. In particular, it is reciprocally movable to the lower surface of the contact glass 2 which is the sub-scanning range of the original document and the position on both outsides of this sub-scanning range (the position of the home position switch 14 and the like). The stability of the scanning speed of the optical systems 11 and 12 and the stability of the amount of lamp light are ensured. The home position switch 14 indicates the initial set position of the first optical system 11, and the timing switch 15 is provided for the forward movement reference, from which it is detected that the optical system is set to the initial set position. In addition, the operation standard of each mechanism in the copying machine 1 is instructed.

A reference original 17 is disposed between the contact glass 2 and the forward movement reference position of the timing switch 15 and on the lower surface of the instruction plate 16 which indicates the leading edge of the original placement position. There is. A gray original is applied to the reference original 17 in consideration of the fact that white streaks can be detected from the copied image and the amount of toner used is relatively small.
The reference original 17 is flush with the contact glass 2 to ensure the detection accuracy.

The image forming means P has a photosensitive drum 18 on the surface of which an electrostatic latent image is formed by irradiation of the original image from the optical mechanism L, and an upstream side along the peripheral surface of the photosensitive drum 18. In this order, the surface of the photosensitive drum 18, which will be described in detail later, is charged to a predetermined potential, and the charging device 19 is equipped with a cleaning mechanism for cleaning the charging wire, and the developing device 20 for visualizing the electrostatic latent image. A transfer device 21 for transferring the original image on the photosensitive drum 18 to a transfer paper, a separating device 22 for separating the transfer paper after the transfer from the photosensitive drum 18, and a cleaning for removing the residual toner on the photosensitive drum 18. And a device 23.

As the paper transport mechanism, a paper feed cassette 24, a paper feed roller 25, and a registration roller pair 26 are arranged in this order from the upstream side in the feeding direction. Further, a registration switch 26a is provided immediately before the registration roller pair 26, and when the transfer paper turns on the registration switch 26a and a preset time elapses, the registration roller pair 26 stops driving. It is supposed to be done. Then, the transfer roller is fed to the photosensitive drum 18 by driving the registration roller pair 26 at a predetermined leading edge timing synchronized with the forward movement of the optical system.
On the other hand, a transport belt 27, a fixing device 28, a pair of discharge rollers 29, a discharge tray 30, and the like are provided as a sheet transport mechanism for the transfer sheet after the transfer.

The reversing device K is a device disposed between the fixing device 28 and the discharge roller pair 29, and is the passage switching plate 3
1, a reverse running roller 32 and a reverse passage 33. The path switching plate 31 is switched to each position shown by a solid line and a broken line in FIG. 1 to linearly guide the transfer sheet from the transport roller pair 34 to the discharge roller pair 29, and the transfer sheet after fixing. Once loaded into the inversion passage 33,
A path for carrying out to the sheet re-feeding mechanism R in the inverted state is formed. The reverse running roller 32 is displaced in position so as to come into contact with one roller of the discharge roller pair 29 when being carried out to the re-feeding mechanism R.

The sheet re-feeding mechanism R forms a return path from the reversing device K to the sheet feeding side, and has an intermediate tray 35 for temporarily storing the transfer sheet and the intermediate tray 35.
Reverse transfer path 36 for conveying the transfer paper to the intermediate tray 35
From the image forming means P to a sheet re-feeding path 37 for re-feeding the transfer sheet. Above the upstream side of the intermediate tray 35, there are a pair of conveying rollers 38, which constitute the reversal communication path 36,
39 and 40 are provided, and conveyance path switching plates 41 and 42 that switch the conveyance distance to the intermediate tray 35 according to the size of the transfer sheet are provided between them.
At the re-feeding end of No. 5, a sending roller 43 for feeding the stored transfer paper and a white streak detecting device G described in detail later are provided.

In the copying machine 1 having the above-mentioned structure, the light of the halogen lamp 4 is reflected by the original, and the reflected image is passed through the reflecting mirrors 6, 7, 8 and the image forming lens 10 and the reflecting mirror 9 and the photosensitive member. It is guided to the drum 18. The photosensitive drum 18 is shown in FIG.
While being rotated in the direction of the arrow, after being charged to a predetermined potential by the charging device 19, the original image is irradiated and exposed to form an electrostatic latent image. The electrostatic latent image on the surface of the photoconductor drum 18 is developed by the developing device 20, and then transferred by the transfer device 21 onto the transfer paper fed from the paper feed cassette 24. The transfer paper after the transfer is separated from the photoconductor drum 18 by the separating device 22, and is conveyed through the conveying belt 27, the fixing device 28 and the discharging roller pair 29 to the discharging tray 3.
0 is ejected. On the other hand, when double-sided copying is performed, the passage switching plate 31 is switched to the solid line position shown in FIG. 1, the transfer paper after fixing is once carried into the reversing passage 33, and then the reversing connecting passage 36 is provided. The transfer surface is placed on the intermediate tray 35 with the transfer surface facing upward, and the sheet is stationary. Then, it is carried out from the intermediate tray 35 by the sending roller 43 at a predetermined timing, is fed to the image forming means P through the re-feeding path 37, and the original image is again formed on the back surface of the transfer sheet by the above-mentioned process. After the transfer, it is discharged onto the discharge tray 30.

Here, the structure of the charging device will be described with reference to FIGS. FIG. 2 is a perspective view showing an example of a charging device applied to the copying machine of the present invention, and FIG. 3 is a view taken in the direction of arrow B in FIG.

As shown in FIG. 2, the charging device 19 has a shield case 52, a charging wire 55 as a corona discharge electrode, and a cleaning mechanism for cleaning the charging wire 55.

The shield case 52 is a long member having a discharge opening 56 in which a stainless plate is bent in a U-shaped cross section, and a front housing 53 is provided at one longitudinal end thereof.
However, the rear housing 54 is fitted and attached to the other end side. A banana chip 57 is screwed and mounted on the outer side of the end surface of the rear housing 54 with a terminal block 58 disposed inside via the end wall of the rear housing 54, and the charging device 19 is mounted on the copying machine 1. The banana chip 57 is configured to be connected to a high voltage power source (not shown).

On the other hand, in the shield case 52, a charging wire 55 such as a tungsten wire is stretched in the longitudinal direction of the shield case 52 from the front housing 53 to the rear housing 54. Charging wire 5
As shown in FIG. 2, one end of the reference numeral 5 is inserted into the hollow rib 59 of the rear housing 54, and the fixing pin 60 is held by being inserted into the hollow rib 59. The front housing 53 is rewound and is rewound by the ribs 61 of the front housing 53.
It is a double wire stretched toward 4, so that the charging property of the photosensitive drum 18 is improved. The terminal end of the charging wire 55 is wound around the one end hook of the tension spring 62, while the tension spring 6
Since the other end side hook of 2 is locked to the hook portion formed on the terminal block 58, the charging wire 55 is stretched in the shield case 52 with a required tension, and at the same time, from the high voltage power source. A voltage is applied to the charging wire 55 via the banana chip 57, the terminal block 58 and the tension spring 62. Then, front and rear covers 53a and 54a are mounted on the upper portions of the front and rear housings 53 and 54, respectively.

On the other hand, in the shield case 52, a cleaning body 63 is movably arranged as a cleaning mechanism for removing and cleaning dirt such as toner and paper powder attached to the tensioned charging wire 55. As shown in FIG. 2, the cleaning body 63 includes a moving frame 63a and a cover 63b mounted on the moving frame 63a with the charging wire 55 interposed therebetween.
A cleaning pad 63c is attached to the lower surface of b for directly slidingly contacting the charging wire 55 to remove and clean dirt. Moving frame 6
As shown in FIGS. 2 and 3, 3a has a pair of leg portions 64, 64 projectingly formed on the lower surface thereof from the shield case 52.
It is fitted in a guide opening groove 65 formed in the longitudinal direction of the bottom surface and is attached so as to project to the back surface of the shield case 52.

The cleaning body 63 is the shield case 5
It is configured to be reciprocally moved along the guide opening groove 65 by the cleaning body driving unit 66 disposed on the back surface of the second member.

As shown in FIG. 3, the cleaning body drive unit 66 is
A cleaning member drive motor 67 such as a stepping motor, which is provided in the front housing 53 and is drive-controlled by a controller (not shown), and the front and rear housings 5
3, 54, respectively, and a front pulley 68 and a rear pulley 69, and an endless moving wire 70 wound around the pulleys 68, 69 a predetermined number of times and then stretched. . Then, the cleaning body drive motor 67 is driven to rotate in the forward and reverse directions, so that the rotational drive is transmitted to the front pulley 68 via the gears 71 and 72,
The moving wire 70 is configured to rotate forward and backward. Fixing tools 73, 73 are fixed to the moving wire 70 at appropriate positions at predetermined intervals.
The leg 64, 64 of 3a holds the moving wire 70 between the fixtures 73, 73 so that the cleaning body 63 is
However, it is adapted to reciprocate in the shield case 52 in conjunction with the forward / reverse rotational movement of the moving wire 70.

A detecting piece 74 is arranged on the moving wire 70, and a movement reference sensor 75 for detecting the detecting piece 74 is arranged near the front pulley 68. As a result, the movement base point (movement reference position) of the cleaning body 63 is designated.

The charging device 19 having the above structure is mounted on the copying machine 1 from the rear housing 54 side so that the discharge opening 56 faces the surface of the photosensitive drum 18. While the charging wire 55 is discharged by applying a predetermined voltage from a high voltage power supply (not shown), the cleaning body drive motor 67 controls the cleaning wire drive motor 67 (not shown) when cleaning the charging wire 55. Driven by the device, the moving wire 70 is rotationally moved. In conjunction with this, the cleaning body 63 reciprocates, and the cleaning pad 63c moves while removing dirt such as toner and paper dust while cleaning while slidingly contacting the charging wire 55.

Next, the white streak detecting device G will be described with reference to the drawings. FIG. 4 is a view taken in the direction of arrow A in FIG. 1 showing an example of the white stripe detection device G applied to the copying machine of the present invention.

The white streak detecting device G is a white streak sensor 4 for detecting a white streak on the transfer paper 44 stored on the intermediate tray 35.
9 and a drive unit 52 for displacing the white stripe sensor 49 in the main scanning direction of the transfer paper 44 (horizontal direction in FIG. 4).

The drive section 52 includes a front pulley 45 and a rear pulley 46 arranged on both front and rear ends of the intermediate tray 35.
And an endless timing belt 47 mounted between the pulleys 45 and 46, and a sensor driving motor 48 such as a stepping motor for driving the front pulley 45 to rotate. The timing belt 47 is configured to be rotated in the normal and reverse directions by being driven in the reverse direction. The white streak sensor 49 is fixed to a proper position of the timing belt 47, and is integrally moved forward and backward in conjunction with the forward and reverse rotational movement of the timing belt 47. White line sensor 49
Is, for example, a reflection type photo sensor including a light emitting element 49a and a light receiving element 49b, and the light emitting element 49a and the light receiving element are arranged so that the white streaks of the transfer paper 44 stored on the intermediate tray 35 can be detected. And 49b are arranged facing downward. In addition, the detection piece 5 is attached to the timing belt 47.
0 is provided, and a detection reference sensor 51 for detecting the detection piece 50 is provided near the front pulley 45.
Is provided. Thereby, the movement base point (detection reference position) of the white streak sensor 49 is designated.

In the normal mode, the intermediate tray 3
5, the transfer paper stored in a stacked form on the sheet 5 and the white line sensor 49.
The pulleys 45 and 46 are arranged so as to have a predetermined height from the upper surface of the intermediate tray 35 so that the above and each other do not interfere with each other.

In the white stripe detecting device G having the above structure, when the sensor driving motor 48 is driven by the control device (not shown), the timing belt 47 is passed through the front pulley 45.
Is rotatively driven, and accordingly, the white line sensor 49 moves forward to detect the white line in the main scanning direction of the transfer paper 35 on the intermediate tray 35, and after the detection, it returns to the base point. It is like this.

Next, a block configuration showing a control system for cleaning the above copying machine will be described with reference to FIG.

Reference numeral 76 denotes a central control unit (hereinafter, referred to as CPU) for integrally controlling the operation of the copying machine 1. For example, it is provided on an operation unit (not shown) provided at an appropriate place on the upper surface of the copying machine body. A control signal is output to the drive control device 77 to switch the copying machine 1 from the normal copying mode to the charging device cleaning mode in response to the operation signal of the mode changeover switch 78, and based on the detection data from the white line sensor 49 described later. Then, the distance from the detection reference position to the white streak occurrence point of the transfer paper is calculated, and the movement amount of the cleaning body 63 is calculated. Further, the calculated distance value is stored in a storage unit provided inside the CPU 76. The home position switch 14 includes the first optical system 11 and the second optical system 1.
When 2 is set to the initial setting position, the detection signal C
Output to PU76. The timing switch 15 is the first
It is turned on by the movement of the optical system 11, and the detection signal is output to the CPU 76. The timer 79 outputs a CP according to the detection signal input of the timing switch 15.
Timing is started based on the control signal from U76, and the stop position of the first optical system 11 is indicated. Here, the first optical system 1
The stop position of 1 means that the first optical system 11 is just the reference document 17
Indicates the position where the original image can be captured.

When the time for the first optical system 11 to reach the above position is measured by the timer 79, the CPU 76
Outputs a control signal to the drive control device 77 to stop the first and second optical systems 11 and 12, and at the same time, the passage switching plate 3 so that the transfer paper is conveyed to the intermediate tray 35.
Operate 1. That is, in the charging device cleaning mode, the CPU 76 positions the transfer position of the reference original document 17 on the transfer paper fed from the paper feeding cassette 24 or the intermediate tray 35 on the intermediate tray 35 so as to face the white line detection device G. The exposure timing is adjusted so that

When the first and second optical systems 11 and 12 are stopped, a transfer paper is fed, the original image of the reference original 17 is transferred to the transfer paper, and the intermediate tray 35 is transferred.
Is stored in.

When the transfer paper is stored in the intermediate tray 35,
The sensor drive motor 48 is driven to drive the white stripe sensor 4
9 starts the forward movement, and the detection of the white line in the main scanning direction of the transfer paper is started. In the CPU 76, the white line sensor 4
9 is the detection reference position, that is, the detection signal from the detection reference sensor 51 indicating the movement base point of the white streak sensor 49 is C
The counting of the number of pulses supplied to the sensor driving motor 48 is started from the time of input to the PU 76. That is, this allows the white line sensor 4 to move from the detection reference position.
The amount of movement of 9 in the main scanning direction is detected.

When the white streak sensor 49 detects a white streak, the detection signal is output to the CPU 76, and the CPU 76 outputs a pulse of the sensor driving motor 48 corresponding to the white streak detection signal. From the number, the distance from the detection reference position to the white line detection position is calculated, and the movement amount of the cleaning body 63 to the contamination position of the charging wire 55 is calculated. When the white streak detection is completed, the CPU 76 drives the cleaning element drive motor 67 to start the forward movement of the cleaning element 63. At this time, the movement base point of the cleaning body 63 is the movement reference sensor 7
5 is designated. Immediately before or when the cleaning body 63 is moved forward and reaches the calculated movement amount, the CPU 76 drives and controls the cleaning body 63 so as to perform a predetermined reciprocating motion set in advance. There is.

Next, the operation of the image forming apparatus of the present invention will be described with reference to the flowchart of FIG.

First, when the mode changeover switch 78 is operated to select the charging device cleaning mode for the charging wire 55 of the charging device 19 in step S1, the first and second optical systems 11 and 12 start to move forward. . When the timer 79 measures the preset time after the first optical system 11 is detected by the timing switch 15, the forward movement of the first and second optical systems 11 and 12 is stopped (step S2). The image of the reference document 17 is irradiated onto the photosensitive drum 18 (step S3). Next, in step S4, the original image on the reference original 17 is transferred onto a transfer paper of a predetermined size, for example, the maximum size, and the transfer paper is stored in the intermediate tray 35 (step S5). Here, when the transfer of the original image onto the transfer paper is completed, the halogen lamp 4 is turned off, but the stopped state of the first and second optical systems 11 and 12 is maintained.

When the transfer paper is stored in the intermediate tray 35,
The sensor drive motor 48 of the white line detection device G is driven. The detection piece 50 is detected by the detection reference sensor 51, and the detection signal is input to the CPU 76 (step S6),
When the detection reference position for the white streak sensor 49 is set,
The CPU 76 starts counting the number of pulses for the sensor driving motor 48, and at the same time, the white line sensor 49 starts detecting white lines while moving forward in the main scanning direction of the transfer sheet (step S7).

When the white streak sensor 49 detects the white streak in the main scanning direction of the transfer paper stored in the intermediate tray 35 and no white streak is detected (NO in step S8). That is, when the charging wire 55 is not contaminated, the process proceeds to step S22, the transfer paper stored in the intermediate tray 35 is discharged onto the discharge tray 30, and the first and second optical elements are System 11,
12 is returned to the initial set position, the flow chart is terminated, and the normal copying mode is restored. At the same time, the white streak sensor 49 may be returned to the reference position.

On the other hand, if the white streak is detected in step S8, that is, if the charging wire 55 is soiled, the process proceeds to step S9. In step S9, the distance from the detection reference position to the white streak generation point is calculated from the count value of the pulse to the sensor driving motor 48 at the time of the white streak detection signal of the white streak sensor 49, and the calculated value is calculated by the CPU 76. To be stored in the storage unit of. At this time, when a plurality of white stripes are detected, a calculation is performed for each of them and a plurality of calculated values are stored. When the white streak sensor 49 finishes detecting the end of the transfer sheet in the main scanning direction (YE in step S10).
S), the sensor driving motor 48 is reversely rotated, and the white line sensor 49 is returned to the reference position (step S1).
1).

When the white line detection is completed, the cleaning member drive motor 67 is subsequently driven, and the cleaning member 63 starts sliding along the charging wire 55 from the movement reference position (step S12). At this time, the CPU 76 reads out the calculated value from the storage unit, and immediately before the cleaning body 63 reaches the dirty position of the charging wire 55, that is, the position of the charging wire 55 corresponding to the white line detection position of the transfer sheet, the cleaning body 63. Drive motor 6
The rotation speed of No. 7 is reduced by a preset number of pulses, and the forward speed of the cleaning element 63 is reduced (step S1).
3). Thereby, the charging wire 55 of the cleaning pad 63c
The frictional force on the charging wire 55 is increased to reliably remove and clean the charging wire 55. Then, when the deceleration of the preset number of pulses is completed, the moving body 63 resumes moving at the normal moving speed again (step S15),
When the end of the charging wire 55 is reached (YES in step S14), the process proceeds to step S16. In step S16, the transfer paper on the intermediate tray 35 is fed again to the image forming means P, and the reference original 17 is again placed on the back surface of the transfer paper.
Image is copied (step S17) and stored again in the intermediate tray 35 (step S18). Then, the detection reference position of the white streak sensor 49 is set again (step S
19) Then, the presence or absence of white streaks on the transfer paper is confirmed (step S20). At this time, the white line sensor 49 is C
Based on the calculated distance value to the white streak detection position stored in the storage unit of the PU 76, only the position where the white streak occurred last time is detected. Here, if the white streak is not detected (YES in step S21), the process proceeds to step S22 to end the present flowchart, but if the white streak is detected again (NO in step S21), step S21 is performed.
Then, the process is returned to 3, and new transfer paper is fed from the paper feed cassette 24. At this time, the previous transfer paper stored in the intermediate tray 35 may be left stored in the intermediate tray 35 or may be discharged first.

If no white streak is finally detected (NO in step S8, YES in step S21), the transfer paper stored in the intermediate tray 35 is discharged onto the discharge tray 30 in step S22, and this flowchart is executed. And the normal copy mode is restored. However, if white lines are always detected even if the white lines are detected and the charging wire 55 is cleaned a preset number of times (always NO in step S21) according to this flowchart, for example, on an operation unit (not shown). The notification means is used to notify that effect.

As described above, according to the image forming apparatus of the present invention, not only the charging wire 55 can be cleaned without taking out the charging device 19, but also the dirty position can be efficiently cleaned.

By the way, in the above embodiment, the white line sensor 49 is configured to move in the main scanning direction of the transfer sheet to detect the white line in one line in the main scanning direction. The sensor 49 may be configured to be movable also in the sub-scanning direction, and may be configured to be able to detect white streaks on a plurality of lines in the main scanning direction of the transfer paper. For example, guides in the sub-scanning direction may be arranged on both sides in the main scanning direction, and the white streak detection device G may be reciprocally moved on the guides by a driving unit such as a motor. In this case, for example, FIG.
The operation shown in the flowchart of FIG.

When the transfer sheet is started to be fed in the charging device cleaning mode (step S30) and the preset time (A time) elapses after the registration switch 26a is turned on, the charging device 19 starts discharging ( This discharge is stopped after a predetermined time (B time) (step S31) (step S32). As a result, the image of the reference original 17 is copied to a part of the proper position of the transfer paper in the sub-scanning direction. Thereafter, the transfer paper is stored in the intermediate tray 35, and white stripe detection is performed by the white stripe detection device G (step S33). When a white stripe is detected, the cleaning element 63 is subjected to the same predetermined cleaning operation as described above. Then, the charging wire 55 is cleaned (step S
34). After cleaning the charging wire 55, the transfer sheet on the intermediate tray 35 is re-fed (step S35), and the registration switch 26a is turned on similarly to the above, and the charging device 19 is discharged after a preset time (A time). Is started (step S36), and this discharge is stopped after a predetermined time (B time) (step S37). As a result, the image of the reference document 17 after the cleaning of the charging wire 55 is copied on the back surface of the transfer paper. Then, in step S38, white lines are confirmed, and if white lines are generated, the charging wire 55 is re-charged.
Then, the same cleaning as described above is performed (step S39).

After that, the transfer paper on the intermediate tray 35 is re-fed again (step S40), and the image of the reference original 17 is copied again on the surface of the transfer paper. At this time, after the registration switch 26a is turned on (A + B) time, the charging device 19 starts discharging (step S41), and a predetermined time (B
After that, the discharge is terminated (step S4).
2). That is, the image of the reference original 17 is copied on the transfer paper at a position adjacent to the image of the reference original 17 that is first copied. Then, this transfer paper is stored in the intermediate tray 35, and the white streak detection device G detects the white streak. However, since the transfer position of the transfer image is displaced from the previous image position, the white streak detection device is detected. G is displaced in the transfer position of the transferred image, that is, in the sub-scanning direction by the distance corresponding to the time (A + B), and the white line sensor 49 detects the white line (step S43). And
When the white streak is generated, the charging wire 55 is cleaned in the same manner as described above (step S44). After that, when a white streak has occurred, that is, when the stain of the charging wire 55 is not eliminated, the transfer paper is repeatedly fed to the image forming means P and copied so as to be adjacent to the previous image in the same manner as above. At the time of white line detection, the white line detection device G is moved in the sub-scanning direction to be detected by the white line sensor 49.

By constructing the image forming apparatus in this way, it is possible to obtain the same effects as in the above embodiment with respect to the cleaning of the charging device 19, and further, the white streak detection and the white streak are performed a plurality of times with one transfer paper. The advantage is that confirmation is possible.

In the above embodiment, when the charging wire 55 is soiled, the cleaning body 63 slows down the moving speed to perform cleaning. However, for example, the soiling position is reciprocated a plurality of times. The cleaning operation of the cleaning body 63 with respect to the charging wire 55 may be appropriately set so that the cleaning operation can be effectively performed according to the contamination state of the charging wire 55.

Further, the copying machine 1 of the above-mentioned embodiment detects the white stripes from the transfer paper to detect the stain position of the charging wire 55,
The purpose is to drive and control the cleaning body 63 so as to efficiently clean the dirty position of the charging wire. In the copying machine 1 having the above-described configuration, for example, the image density is detected in accordance with the white streak detection. However, it can be applied to other purposes such as the adjustment of the charge amount, the adjustment of the light control plate, or the developing bias value.

Further, in the above embodiment, the white stripe sensor 49 is constructed so as to be moved in the main scanning direction of the transfer paper, but it may be constructed by using a line sensor, for example. According to this, the drive device for moving the white line sensor 49 becomes unnecessary, and the white line can be detected with a simple configuration.

In the above embodiment, the charging wire 5
The cleaning of No. 5 is performed by operating the mode changeover switch 78. For example, the cleaning of No. 5 is performed in synchronization with the turning on of the main switch or periodically according to the number of times of copying, the elapsed time, and the like. Good.

[0062]

As described above, according to the present invention, the white streak detection is performed on the transfer paper on which the reference original is transferred to detect the stain position of the charging wire, and the cleaning means detects the contamination position of the charging wire. Since a predetermined cleaning operation is performed at the stain position, it is possible to efficiently clean and remove dirt such as toner and paper dust that has adhered to the charging wire, so that the charging wire can be swiftly and reliably cleaned. Becomes

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an example of an image forming apparatus of the present invention.

FIG. 2 is a perspective view showing an example of a charging device applied to the image forming apparatus of the present invention.

FIG. 3 is a view taken in the direction of arrow B in FIG. 2, showing a drive unit of the charging device applied to the image forming apparatus of the present invention.

FIG. 4 is a view taken in the direction of arrow A in FIG. 1, showing an example of a white line detection device applied to the image forming apparatus of the present invention.

FIG. 5 is a block configuration diagram showing a control system for performing a cleaning operation in the image forming apparatus of the present invention.

FIG. 6 is a flowchart showing the operation of the image forming apparatus of the present invention.

FIG. 7 is a flowchart showing the operation of another example of the white line detection device.

[Explanation of symbols]

 L Optical Mechanism P Image Forming Device K Reversing Device R Refeeding Mechanism G White Line Detection Device 17 Reference Document 19 Charging Device 35 Intermediate Tray 55 Charging Wire 63 Cleaning Body

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Ikuichi Kitagawa 1-2-2 Tamatsukuri, Chuo-ku, Osaka Mita Engineering Co., Ltd. (72) Inventor Mitsugu Miyamoto 1-228 Tamatsukuri, Chuo-ku, Osaka Within Mita Engineering Co., Ltd.

Claims (6)

[Claims] 1. An image in which an image of a reference document read by an optical system is guided by a charging device onto a photoconductor charged to a predetermined potential to form a latent image, and a toner image is further formed and transferred to a transfer paper. In the forming device, a cleaning member slidable along the charging wire of the charging device, a driving unit that allows the cleaning member to reciprocate between both sides of the charging wire, and an image of the reference document are transferred. Detecting means for detecting white stripes in the image over at least one line in the main scanning direction of the transferred paper, storage means for storing the white stripe detection position detected by the detecting means, and the stored white stripes An image forming apparatus comprising: a cleaning control unit configured to slide the cleaning member to a position and control the drive unit to perform a predetermined cleaning operation at the white streak position. 2. The image forming apparatus according to claim 1, wherein the cleaning control unit controls the driving unit so as to reciprocate the white streak position a plurality of times. 3. The image forming apparatus according to claim 1, wherein the cleaning control unit controls the driving unit so as to reduce the sliding speed with respect to the white streak position. 4. The image forming apparatus according to claim 1,
The optical system is capable of reciprocating movement, and a document placing plate surface arranged within the range is set as a sub-scanning range, while the reference document is within the reciprocating range and sub-scanning. It is arranged at a position outside the range, and the lower surface is formed on the lower surface of a member whose surface is flush with the document mounting surface, and the optical system stops below this member when reading the reference document. An image forming apparatus characterized by being put into a state. 5. The image forming apparatus according to claim 1,
When the cleaning means cleans the charging wire based on the detection of the white stripes on the transfer sheet, the refeeding path is provided to reverse the transfer sheet on which the reference document is transferred and to re-feed it to the photoconductor again. An image forming apparatus comprising: a sheet re-feeding control unit that re-feeds the transfer sheet from the sheet re-feeding path to the photoconductor and guides the sheet again to the sheet re-feeding path after transfer. 6. The image forming apparatus according to claim 5,
When the re-feeding control unit guides the transfer sheet to the re-feeding path, the detection unit is configured to detect the presence or absence of a white line only at the previous white line detection position. Image forming apparatus.