JP2003307987A - Image formation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image formation device in which the service life of a paper powder removing means is prolonged and a space for the storage unit of paper powder is not required so much. <P>SOLUTION: A rotatable paper powder removing brush 26 abutted on a photosensitive drum 13 for printing is included. The number of print sheets is counted by a sheet number counter 12a for each printing during a printing processing (ST1 and ST2), and when printing is ended (ST3), whether or not the counted value of the sheet number counter 12a reaches a prescribed sheet number is judged (ST4). When it reaches the prescribed sheet number, the photosensitive drum 13 is rotated for a prescribed angle (30°) (ST7), the paper powder removing brush 26 is slightly rotated and the new surface of the paper powder removing brush 26 is brought into contact with the photosensitive drum 13. In such a manner, the paper powder removing brush 26 is intermittently rotated. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a facsimile machine and a copying machine.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic image forming apparatus, a photosensitive member driven by a rotary drive mechanism, a charging means for charging the photosensitive member to a positive polarity, and image information on the charged photosensitive member. Exposure means for writing as an electrostatic latent image, developing means for developing the electrostatic latent image formed by the exposure means, transfer means for transferring the developed image to a recording medium,
There is known one provided with a paper dust removing means for removing the paper dust in contact with the surface of the photoconductor.

In this type of image forming apparatus, in recent years, attention has been paid to a positive charging process for positively charging the surface of the photoconductor.

[0004]

With the above-mentioned positive charging,
Corona charge produces ozone in negative discharge, but positive discharge does not have such an inconvenience, so corona charge can be used for the charger, and it has the advantage of uniformly charging the surface of the photoconductor at low cost. ing. Also,
Positively charged toner suitable for the positive charging process has been developed and is in the stage of practical application.

However, paper dust is often negatively charged,
This adheres to the surface of the photoconductor that is positively charged at the time of transfer, resulting in poor charging and white spots. To avoid this problem,
Although it is necessary to provide a brush for removing paper dust, a fixed type brush has a shorter life than a drum. Therefore, when the paper dust removing brush and the photoconductor are combined into one unit, the unit life of the paper dust removing brush is determined and the photosensitive drum that is still usable is discarded.

Therefore, in the case of a rotary brush, it is necessary to remove the paper dust adhering to the brush by applying a flicker, and a space for storing the removed paper dust is required.

The present invention has been made in view of the above-mentioned problems, and the life of the paper dust removing means is long, and therefore the life of the photosensitive member and the integrated unit is also long, and yet a space for storing the paper dust is provided. An object is to provide an image forming apparatus that does not require much.

[0008]

SUMMARY OF THE INVENTION An image forming apparatus according to the present invention comprises a photoconductor driven by a rotary drive mechanism, a charging unit for positively charging the photoconductor, and image information on the charged photoconductor. An exposure means for writing the electrostatic latent image, a developing means for developing the electrostatic latent image formed by the exposure means, a transfer means for transferring the developed image to a recording medium,
A device provided with a paper dust removing unit that comes into contact with the surface of the photoconductor and removes the paper dust is provided with a rotating mechanism that intermittently rotates the paper dust removing unit and a control unit that controls the rotating mechanism.

In the image forming apparatus of the present invention, since the paper dust removing means rotates intermittently, different portions of the removing means come into contact with the photoconductor, so that the life of the paper dust removing means is extended and the paper dust removing means is constantly rotated. Therefore, it is not necessary to remove the paper dust adhering to the paper dust removing means due to flicker or the like.

In the image forming apparatus of the present invention, the rotation mechanism of the paper dust removing means comes into contact with the rotation driving mechanism of the photoconductor through a one-way clutch, and when the control means reaches a predetermined condition, It is preferable that the photosensitive member is rotated in the reverse direction by the rotation driving mechanism of the photosensitive member and the paper dust removing means is rotated by a predetermined angle.

In the image forming apparatus of the present invention,
For example, the control means may reverse the photoconductor after forming a predetermined number of images on the recording medium.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to embodiments.

A schematic configuration diagram of the image forming apparatus according to the embodiment is shown in FIG. 1 (part) and FIG. 2 (remaining part). The image forming apparatus is configured as a so-called multi-function peripheral having a facsimile function and a copy function, and in FIG. 1, an MPU (control unit) 1 and an NCU (network control circuit: Net) are used.
work Control Unit) 2, MODEM
3, ROM 4, RAM 5, image memory (DRAM) 6,
CODEC (Coder and Decoder)
7, an operation unit 8, a scanner 9, and a printer interface 10. Further, this apparatus includes an electrophotographic printer configured as shown in FIG. 2 and a recording medium (paper).
And a transport mechanism section for transporting the sheet from a sheet feeding cassette (not shown) to the transfer roller 21 and the press roller 25.

The MPU 1 controls each part constituting this device. The NCU 2 has a function of controlling a connection with a telephone line network (PSTN), a function of transmitting a dial signal corresponding to a telephone number (including a FAX number) of a destination, and a function of detecting an incoming call. MODEM3 is I
TU (International Telecommunication Union) -T Recommendation T. 30 based on the facsimile transmission control procedure according to V.30. 17, V.I. Two
7ter, v. The transmission data is modulated and the reception data is demodulated according to 29 or the like. Alternatively, V. Three
Modulation of transmission data and demodulation of reception data according to 4 are performed.

The ROM 4 stores a program for controlling this device. The RAM 5 temporarily stores data and the like. The image memory 6 includes received image data and the scanner 9
The image data read by is temporarily stored. CODEC
MH, M for transmitting the read image data
The received image data is encoded by the R, MMR method or the like, and the received image data is decoded. The operation unit 8 is used by the user to instruct FAX transmission / reception, printing, and the like. The scanner 9 reads image data of a document when transmitting by FAX. Printer interface 10
Receives a print command and data from the PC and sends it to the printer controller 12 described later.

The printer of this apparatus is provided with a printer controller 12 for controlling each section of the printer in FIG. A number counter 12a is provided in the printer controller 12.
Have. Inside the printer, a photosensitive drum 13 having a photoconductive film on the outer peripheral surface is arranged as a photosensitive member, and the photosensitive drum 13 is rotated by a motor 41. This photosensitive drum 1
A scorotron charger 14 is arranged as a charger around 3 and a predetermined bias voltage is applied to the scorotron charger 14 by a charging bias applying circuit 15. The scorotron charger 14 to which the bias voltage is applied moves the outer peripheral surface of the photosensitive drum 13 by about +8.
It is uniformly charged to 00V. The LED print head 16 as an exposure unit arranged around the photosensitive drum 13 is
A large number of LEDs are arranged side by side, and the outer peripheral surface of the photosensitive drum 13 is irradiated with light based on the input image information to form an electrostatic latent image corresponding to the image information on the outer peripheral surface.

Further, the developing device arranged around the photosensitive drum 13 is composed of a supply roller 17, a developing roller 18, a blade 19, a developing device bias applying circuit 20 and the like. The supply roller 17 supplies the toner from the toner case (toner container 20 of FIG. 3) containing the toner to the developing roller 18 while charging the toner. The developing roller bias applying circuit 20 applies a predetermined bias to the supply roller 17. A voltage (+ 300V to + 700V) is applied. A predetermined bias voltage (+ 300V to + 600V, preferably about + 450V) is applied to the developing roller 18 arranged in contact with the supply roller 17 and the photosensitive drum 13 by the developing device bias applying circuit 20.

The blade 19 elastically contacts the outer peripheral surface of the developing roller 18 to make the layer thickness of the toner adhered to the outer peripheral surface of the developing roller 18 uniform. The blade 19 has a developing device bias applying circuit. A predetermined bias voltage (+ 300V to + 700V) is applied by 20.

Further, a transfer roller 21 as a transfer device arranged around the photosensitive drum 13 is arranged so as to come into contact with the outer peripheral surface of the photosensitive drum 13 with a sheet conveying path interposed therebetween, and is rotated by a motor 41. A predetermined bias voltage is applied to the transfer roller 21 by the transfer bias applying circuit 22.

The fixing device arranged on the paper delivery side of the paper transport path is composed of a heating roller 23 having a heater, a heater drive circuit 24, a press roller 25 and the like. The heater of the heating roller 23 heats the outer peripheral surface of the heating roller 23 to a predetermined temperature by the heater driving circuit 24.
The heating roller 23 and the press roller 25 are the transfer roller 21.
The toner image on the paper is fixed by heating and pressing the paper after the transfer.

In this apparatus, a paper dust removing brush 26 is arranged around the photosensitive drum 13 between the scorotron charger 14 and the transfer roller 21. As shown in FIG. 4, the paper dust removing brush 26 has a shaft 51 on which the photosensitive drum 1 is attached.
A gear 53 that meshes with the third gear 52 is provided, and this gear 53 has a one-way clutch 54. The one-way clutch 54 transmits the reverse rotation direction of the photosensitive drum 13. During normal rotation of the photosensitive drum 13, the rotating paper dust removing brush 26 is held by a brake or the like so as not to rotate together. The paper dust removing brush 26 rotates the photosensitive drum 13 in the reverse direction when the number of prints reaches a predetermined number, and rotates accordingly. Since the reverse rotation time of the photosensitive drum 13 is a time corresponding to a drum rotation angle of about 30 degrees, there is no adverse effect due to the reverse rotation.

On the paper feeding side, a paper feeding mechanism is provided for taking out the papers set in a paper feeding cassette (not shown) one by one. In this paper feed mechanism, the paper feed roller 40 and the motor 41 are connected via a clutch 42, and when the paper is taken out from the paper feed cassette 45, the paper feed roller 40 is connected to the motor 41 by the clutch 42. By rotating 40, the sheets in the sheet feeding cassette are taken out one by one. FIG. 3 shows a specific mechanical cross section of the printer unit. The paper dust removing brush separating plate (flicker) 26a shown in FIG. 3 is not essential in the present invention.

The operation of the image forming apparatus constructed as described above will be summarized.
Is uniformly charged to about +800 V (A in FIG. 5), an electrostatic latent image corresponding to image information is formed on the photosensitive drum 13 by the LED print head 16 (B in FIG. 5), and the developing roller (FIG. 5) is formed. C) 18 causes toner to be attracted to the electrostatic latent image on the photosensitive drum 13 (D in FIG. 5), and a toner image is formed on the photosensitive drum 13. Then, the toner image on the photosensitive drum 13 is transferred onto the sheet by the transfer roller 21 (E in FIG. 5). After the transfer, the paper is heated and pressed by the heating roller 23 and the press roller 25, and the toner image is fixed on the paper as a permanent image. The paper dust is negatively charged, and is attracted by the positive current of the photosensitive drum 13, so that the photosensitive drum 1
Adhere to 3. The attached paper dust is removed by the paper dust removing brush 26 as the photosensitive drum 13 rotates.

Next, the processing operation of the intermittent rotation of the paper dust removing brush 26 in the facsimile apparatus of this embodiment will be described with reference to the flow chart shown in FIG. When the operation starts,
First, in step ST1, it is determined whether the processing command is print. If it is not a print, the process waits in step ST1 and does not proceed to the subsequent processes. on the other hand,
If it is a print command, the process proceeds to step ST2. In step ST2, the printer unit executes the print processing. The processing itself here is normally performed, and is not particularly new. While performing this print process, the paper dust removing brush 26
In order to determine whether or not to rotate, the number of prints is cumulatively counted since the last reset.

When the print processing is performed, the next step ST
Move to 3. In step ST3, it is determined whether or not printing is completed. If printing has not ended, the process returns to step ST2 and printing is continued. On the other hand, when printing is completed, the process proceeds to step ST4. In step ST4, it is determined whether or not the count value of the number counter 12a has reached a preset number of sheets. If the number of sheets has not reached the predetermined number, it is not necessary to rotate the paper dust removing brush 26 yet, so that nothing is done and the process ends. On the other hand, when the number of sheets reaches the predetermined number, the process proceeds to step ST5.

In step ST5, it is determined whether or not the job being executed is completed. Normally, printing is completed, and the job is completed, so the process proceeds to step ST6. In step ST6, the high voltage power supply and the motor 41 are turned off. As a result, the photosensitive drum 13 also stops.
Then, the process proceeds to step ST7. In step ST7, the motor 41 is rotated by a predetermined angle to rotate the photosensitive drum 1
3 is rotated in the reverse direction, and the paper dust removing brush 26 is rotated by a predetermined angle. As a result, the contact position of the paper dust removing brush 26 with the photosensitive drum 13 becomes a new position, and the contact position so far becomes non-contact, and the same effect as when a new fixed type paper dust removing device is replaced can be obtained. Finally, the process proceeds to step ST8. Then, the number counter is reset, and the process ends.

In the above embodiment, the paper dust removing brush is rotated every time the number of prints reaches a predetermined number, but it may be rotated every predetermined time, or may be rotated when a predetermined date is reached. You may do it. Alternatively, since the amount of paper dust has increased, it may be visually confirmed and moved manually.

In the above embodiment, the paper dust removing brush 26 is attached to the drum unit, but it may be attached to the apparatus body. In the former case, replacing the drum unit also replaces the paper dust removal brush attached to the drum unit, so the paper dust removal performance will be restored, but if the paper dust removal brush is attached to the machine body side, the paper dust removal brush will be removed. Performance recovery cannot be expected. Therefore, each time the drum unit is replaced, the contact surface of the paper dust removing brush with the photosensitive drum is switched, and the paper dust is removed by a new cleaning surface. An example of this configuration is shown in FIG.
(B) and a side view (c)].

In FIG. 7C, the rotary shaft 61 of the photosensitive drum 13 is rotatably supported by the drum unit 60, and a drum gear 62 is attached to the rotary shaft 61 adjacent to the end of the photosensitive drum 13. There is. When the rotating shaft 61 rotates, the photosensitive drum 13 and the drum gear 62 rotate together.

On the other hand, the paper dust removing brush 26 has a roller shape here, and the rotary shaft 71 of the paper dust removing brush 26 is rotatably supported by the main body frame 70 via a one-way bearing 72, and the rotary shaft 71 has a rotary shaft 71. A one-way gear 73 is attached adjacent to the end of the paper dust removing brush 26. The one-way gear 73 meshes with the drum gear 62. The one-way bearing 72 is fixed to the main body frame 70, and supports the rotation of the rotating shaft 71 in a fixed state.

According to this mechanism, when the motor 41 rotates forward (during normal printing), the photosensitive drum 13 rotates in the direction of the arrow as shown in FIG. 7A. At this time,
The one-way gear 73 that meshes with the drum gear 62 also rotates, but the one-way gear 73 only idles with respect to the rotation shaft 71, and the rotation shaft 71 does not rotate. Therefore, the position of the paper dust removing brush 26 remains fixed and does not change. Of course, even when the motor 41 does not rotate, the paper dust removing brush 2
The position of 6 remains fixed.

When replacing the drum unit 60, the motor 41 is reversely rotated for a predetermined time. At this time,
As shown in (b), the photosensitive drum 13 rotates in the arrow direction. Along with this, the one-way gear 73 also rotates. In this case, the one-way gear 73 rotates in the rotation shaft 7
1, the rotary shaft 71 also rotates. Therefore, the paper dust removing brush 26 also rotates, and the contact position of the paper dust removing brush 26 with the photosensitive drum 13 changes. As a result, the new cleaning surface of the paper dust removing brush 26 contacts the photosensitive drum 13, and the paper dust removing performance is restored.

Further, in this case, since the paper dust removing brush 26 is attached to the main body frame 70 (apparatus main body side), the cost of the drum unit 60 which is a consumable item can be reduced. The time for rotating the paper dust removing brush 26 is, as described above, the time corresponding to the rotation angle of the paper dust removing brush 26 of about 30 degrees.

[0034]

According to the present invention, since the paper dust removing means is provided with the rotating mechanism for intermittently rotating the paper dust removing means and the control means for controlling the rotating mechanism, the paper dust removing means rotates intermittently. Since different parts of the removing means come into contact with the photoconductor, the life of the paper dust removing means is extended and the paper dust removing means does not always rotate. There is no need. Therefore, it is not necessary to take a space for storing paper dust, and the device can be downsized.

[Brief description of drawings]

FIG. 1 is a block diagram (a part) showing a configuration example of a facsimile apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram (remaining part) showing an example of the configuration of the facsimile apparatus according to the first embodiment together with FIG.

FIG. 3 is a cross-sectional view showing a specific configuration of a printer unit of the facsimile apparatus according to the same embodiment.

FIG. 4 is a diagram illustrating a relationship between a photosensitive drum and a paper dust removing brush of the printer unit.

FIG. 5 is a diagram showing voltage levels of respective units for explaining a printing operation of the printer unit.

FIG. 6 is a flowchart for explaining a rotation process of the paper dust removing brush of the facsimile apparatus according to the embodiment.

FIG. 7 is a view showing a linking mechanism between the photosensitive drum and the paper dust removing brush of the facsimile apparatus according to the embodiment.

[Explanation of symbols]

1 MPU 12 Printer controller 12a Sheet counter 13 Photosensitive drum 14 Scorotron Charger 16 LED print head 17 Supply roller 18 Developing roller 26 Paper dust removing brush 41 motor 52,53 gears 54 one-way clutch

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H027 DA45 ED27 EE02 EE05 EE07                       EF11                 2H134 GA01 GB05 HB01 HB07 HB18                       KA28 KB05 KB14 KC10 KF02                       KF05 KG08 KH03 KH09 KH15

Claims (3)

[Claims] 1. A photosensitive member driven by a rotary drive mechanism,
Charging means for positively charging the photoconductor, exposing means for writing image information on the charged photoconductor as an electrostatic latent image, and developing means for developing the electrostatic latent image formed by the exposing means. In an image forming apparatus equipped with a transfer means for transferring a developed image to a recording medium and a paper dust removing means for removing the paper dust in contact with the surface of the photoconductor, a rotation for intermittently rotating the paper dust removing means An image forming apparatus comprising: a mechanism and a control unit that controls a rotating mechanism. 2. The rotation mechanism of the paper dust removing means comes into contact with the rotation driving mechanism of the photoconductor through a one-way clutch, and when the control means reaches a predetermined condition, the rotation driving mechanism of the photoconductor. The image forming apparatus according to claim 1, wherein the photoconductor is rotated in the reverse direction to rotate the paper dust removing unit by a predetermined angle. 3. The image forming apparatus according to claim 2, wherein the control means reverses the photosensitive member when a predetermined number of images are formed on the recording medium.