KR100274637B1 - Method and apparatus clining of electronic image forming device - Google Patents

Abstract

SUMMARY OF THE INVENTION The present invention provides a cleaning method and apparatus for an electrophotographic developer which prevents the transfer roller from being contaminated by the residual toner by collecting the residual toner contaminated with the transfer roller when the toner is replaced.

An electrophotographic developer for injecting toner onto an electrostatic latent image formed on a photosensitive drum, transferring a visible image developed by the toner to a printing paper by a transfer roller, and fixing the visible image transferred to the printing paper by heat and pressure in a fixing unit. In the cleaning method, a residual amount of toner is sensed to confirm replacement time of the toner, and when the toner is exhausted, the transfer voltage is reduced to a voltage level lower than the surface potential of the photosensitive drum to remove unnecessary toner remaining in the transfer roller. It is characterized by.

Description

Method and apparatus for cleaning electrophotographic developer

The present invention relates to a method and apparatus for cleaning an electrophotographic developer, and more particularly, to improve the print quality when a new toner is replaced by recovering the residual toner of the transfer roller as a photosensitive drum when the toner is replaced in the electrophotographic developer. The present invention relates to a method and apparatus for cleaning an electrophotographic developer.

In general, an electrophotographic developing device such as a copying machine, a printer, or the like, as shown in FIG. 1, has a pickup roller 1, a charging roller 2, and a photosensitive drum (OPC: Organic Photoconductive) for printing predetermined image data on printing paper. 3), a transfer roller 4, a developing roller 5, a supply roller 6, a fixing unit 7, an exposure apparatus 8, and a cleaning braid 9.

Here, the voltage applied to each component is a charging voltage of -1.4 [kW] for the charging roller 2, a developing voltage of -300 [V] for the developing roller 5, and +2.0 [kW for the transfer roller 4; ] And a supply voltage of -500 [V] are applied to the supply roller 6. That is, when the charging roller 2 charged by the high-voltage charging voltage rotates and evenly charges the photosensitive member formed on the outer circumferential surface of the photosensitive drum 3, the photosensitive drum 3 with the light generated by the exposure apparatus 8 is charged. The electrostatic latent image to be printed is formed on the surface of the film. Thereafter, a potential difference is generated between the supply roller 6 to which the high voltage supply voltage is applied and the developing roller 5 to which the voltage of a level lower than the supply roller 6 is applied. Therefore, the toner of the negative charge component is transferred from the supply roller 6 to the developing roller 5, and the toner supplied to the developing roller 5 is applied to an electrostatic latent image formed on the surface of the photosensitive drum 3, thereby causing a visible image. To form. The high pressure transfer roller 4 transfers the visible image formed by the toner applied to the surface of the photosensitive drum 3 to the printing paper 10 to be transported. The visible image transferred to the printing paper 10 is fixed to the printing paper 10 by the high heat and pressure of the fixing unit 7, thereby completing the printing process. In addition, when the toner applied to the photosensitive drum 3 is not transferred to the printing paper 10, the cleaning blade 9 mechanically removes the remaining toner remaining on the photosensitive drum 3.

If the toner is used up during the printing process, the user needs to replace it with a new one. Even when the TONER EMPTY status is reached, the user may not be warned. TONER EMPTY "message is only sent to the user via the printer's display.

However, when it is time to replace the toner to continue the printing process as described above, the printing roller is performed thousands of times to tens of thousands of times, the transfer roller is contaminated by the remaining toner. Therefore, if the printing operation is continued without removing the remaining toner, there is a problem of deterioration of the print quality.

In addition, even when it is time to replace the toner, the user is not easily recognized because the "TONER EMPTY" message is notified to the user through the display window of the printer.

Accordingly, the present invention has been made to solve such problems, and an object of the present invention is to recover the residual toner contaminated with the transfer roller to the photosensitive drum when replacing the toner, thereby preventing the print quality from being degraded due to the residual toner. The present invention provides a cleaning method of an electrophotographic developer.

In addition, another object of the present invention is to provide a cleaning apparatus of an electrophotographic developer for achieving the above object.

Another object of the present invention is to remove the residual toner contaminated by the transfer roller and then to release the lock state of the cover mounted on the electrophotographic developer, so that the user can easily determine the replacement time of the toner and make the replacement easier. The present invention provides a cleaning apparatus for a developer.

1 is a schematic structural diagram of a general electrophotographic developer,

2 is a schematic block diagram of an electrophotographic developer including a cleaning apparatus for a transfer roller according to the present invention;

3 is an operation flowchart for performing the cleaning method of the transfer roller according to the present invention,

4 is a voltage waveform diagram supplied to each component part of the electrophotographic developer.

<Description of the code | symbol about the principal part of drawing>

2: charging roller 3: photosensitive drum

4: transfer roller

20: central processing unit 21: power conversion unit

22: transfer voltage control unit 23: memory

24: remaining toner sensor 25: solenoid

A feature of the present invention for achieving the above object is to spray the toner on the electrostatic latent image formed on the photosensitive drum, transfer the visible image developed by the toner to the printing paper in the transfer roller, and the visible image transferred to the printing paper. A cleaning method of an electrophotographic developer in which a fuser is fixed by heat and pressure, the toner remaining amount detecting step of detecting a remaining amount of toner to confirm replacement time of the toner, and when the toner is exhausted, unnecessary toner remaining in the transfer roller. And a depressurizing step of reducing the transfer voltage to a voltage level lower than the surface potential of the photosensitive drum for removal.

Preferably, the cleaning method of the electrophotographic developer further includes a release step of releasing a locked state of a cover installed in the electrophotographic developer after the decompression step is performed.

Another feature of the present invention is to spray the toner on the electrostatic latent image formed on the photosensitive drum, transfer the visible image developed by the toner to the printing paper in the transfer roller, and fix the visible image transferred to the printing paper with heat and pressure in the fixing unit. In the cleaning apparatus of an electrophotographic developer, a toner remaining amount sensor for detecting a remaining amount of toner, a transfer voltage adjusting unit for controlling a voltage supplied to a transfer roller, and a toner remaining amount sensor for checking a toner replacement time And a central processing unit for controlling the transfer voltage adjusting unit according to the result. When the toner is exhausted as a result of the detection by the toner remaining sensor, the transfer voltage applied to the transfer roller is lower than the surface potential of the photosensitive drum. It is to control the transfer voltage adjusting unit to reduce the pressure to a level.

Preferably, the cleaning apparatus of the electrophotographic developer further includes a solenoid for releasing the locking state of the cover mounted to the electrophotographic developer under the control of the central processing unit, and the central processing unit is a cleaning operation of the transfer roller. After the predetermined time is performed, the solenoid is controlled to operate.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a schematic block diagram of an electrophotographic developer including a cleaning apparatus for a transfer roller according to the present invention. In FIG. 2, the same reference numerals as in FIG. 1 denote the same parts, and thus, redundant descriptions thereof will be omitted and only essential components of the present invention will be described.

2, the central processing unit 20 controls the electrophotographic developer as a whole according to a predetermined program.

The power converter 21 receives a commercial voltage (110V / 220V) for home use, converts (steps up) the voltage level required by the printer engine, and then applies it to the printer engine under the control of the central processing unit 20.

The transfer voltage adjusting unit 22 controls the voltage level applied to the transfer roller 4 under the control of the central processing unit 20.

The memory 23 stores various programs for the central processing unit 20 to control the electrophotographic developer, and stores image data to be printed through a printer engine.

The toner remaining amount detection sensor 24 detects the remaining amount of toner, converts the state into an electrical signal, and inputs it to the central processing unit 20.

The solenoid 25 releases the locked state of the cover mounted to the electrophotographic developer under the control of the central processing unit 20.

The operation panel 26 is composed of a display window for displaying the operation and error state of the electrophotographic developer and a key matrix selectable in various modes to set the condition of the device.

Referring to Figures 3 and 4 with respect to the operation of the present invention having such a configuration as follows.

When the print job command is received (S10), the central processing unit 20 controls the power conversion unit 21 to output the respective voltages required from each component inside the printer engine. In the conventional electrophotographic developing apparatus, the charging voltage applied to the charging roller 2 is -1.4 [kW], the developing voltage applied to the developing roller 5 is -300 [V], and the transfer roller 4 is applied. The transfer voltage is +2.0 [kV] and the supply voltage applied to the supply roller 6 has a voltage level of -500 [V].

Therefore, the power conversion unit 21 uses the domestic commercial voltage as the charging voltage (-1.4 [kW]), the developing voltage (-300 [V]), the transfer voltage (+2.0 [kW]), and the supply voltage (-500 [V]. ]) By supplying each of them sequentially, thereby charging each of the rollers 2, 4, 5, and 6 in a predetermined order (S11).

After charging each of the rollers 2, 4, 5, and 6 according to a predetermined order, a printing operation is performed (S12), and the charging roller 2 charges the surface of the photosensitive drum 3 to a constant potential. After the data to be printed is modulated into an optical signal by the exposure apparatus 8, the optical signal is irradiated onto the photosensitive drum 3 to form an electrostatic latent image on the surface of the photosensitive drum 3.

Further, as the feed roller 6 is charged, the toner is applied to the surface of the feed roller 6, and the toner 6 is applied to the feed roller 6 by a potential difference between the potential of the feed roller 6 and the potential of the developing roller 5. The applied toner is delivered to the surface of the developing roller 5. That is, when a potential difference occurs, the toner carrying the negative charge component moves from the supply roller 6 having a low voltage level to the developing roller 5 having a high voltage level.

On the other hand, the surface of the photosensitive drum (3) has a potential of approximately -800 [V] by the charging voltage of -1.4 [kV] supplied from the charging roller (2), the light emitted from the exposure device (8) As a result, the electrostatic latent image has a potential of 0 [V].

On the contrary, since the developing roller 5 is charged to a potential of -300 [V], the toner applied to the surface of the developing roller 5 is exposed to the photosensitive drum 3 according to the flow of electric force lines and toner as mentioned above. Electrostatic latent image is applied. Thus, the electrostatic latent image is visualized by the toner.

In this way, the visible image formed on the photosensitive drum 3 is transferred to the transfer roller 4 side by the high pressure of the transfer roller 4, since the paper is transferred between the photosensitive drum 3 and the transfer roller 4. The visible image is thus transferred to the paper.

Thereafter, the toner transferred to the sheet is fused to the sheet due to the high temperature and the high pressure of the fixing unit 7, and thus the printing operation for one page of image data is finished.

By repeating this process, it is checked whether the print job is finished (S13), and if the print result is not finished, the toner remaining amount sensor 24 searches whether the TONER EMPTY state is detected (S14).

That is, the sensors 24 for detecting the remaining amount of toner are formed on both sides of the toner cartridge, which are formed on one side to emit light, and the other side are formed on one side to receive the light emitted from the light emitting part. It consists of a light receiving unit. When toner is present in the toner cartridge, light emitted from the light emitting unit does not reach the light receiving unit, and when the toner of the toner cartridge is exhausted, light emitted from the light emitting unit is received by the light receiving unit. Therefore, the central processing unit 20 recognizes the TONER EMPTY state as light is received by the light receiving unit of the toner remaining amount detecting sensor 24.

As a result of the search, when the toner is to be replaced, the central processing unit 20 controls the power converter 21 to cut off the developing voltage and supply voltage applied to the developing roller 5 and the supply roller 6. The ground potential is supplied to the transfer roller 4 so that the voltage of the transfer roller 4 has a voltage level lower than the surface potential of the photosensitive drum 3 charged by the charging roller 2. Is applied (S15) (see Fig. 4).

Therefore, unnecessary toner remaining in the transfer roller 4 is transferred to the surface of the photosensitive drum 3 by the potential difference between the potential of the transfer roller 4 and the photosensitive drum 3. That is, when a potential difference occurs, the toner displaces the negative charge component from the transfer roller 4 having a low voltage level to the photosensitive drum 3 having a high voltage level, and the toner moved to the photosensitive drum 3 is moved to the cleaning braid 9. Mechanically removed.

On the other hand, the central processing unit 20 checks whether the predetermined time has elapsed (S16), and when it is determined that the predetermined time has elapsed, cuts off the voltage applied to the transfer roller 4 and the charging roller 2, and then the solenoid ( By applying power to the operation 25) to unlock the cover mounted to the electrophotographic developer (S17).

Therefore, printing quality can be improved by removing the toner contaminated with the transfer roller before replacing the toner.

As described above, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

As described above, the cleaning method and apparatus of the electrophotographic developer according to the present invention has the following advantages.

First, since the toner remaining in the transfer roller is recovered by a photosensitive drum and cleaned before replacing the toner, the print quality can be improved when the toner is replaced with a new toner.

Second, when the toner is replaced, the cover of the electrophotographic developer is unlocked after cleaning the transfer roller, so that the user can easily recognize when to replace the toner and unlock the cover to replace the toner. There is no need for a separate operation.

Claims (4)

A method of cleaning an electrophotographic developer in which toner is sprayed on an electrostatic latent image formed on a photosensitive drum, the visible image developed by the toner is transferred onto a printing paper by a transfer roller, and the visible image transferred on the printing paper is fixed by heat and pressure in the fixing unit. In: A toner remaining amount detecting step of detecting a remaining amount of toner to confirm replacement time of the toner; And a decompression step of reducing the transfer voltage to a voltage level lower than the surface potential of the photosensitive drum to remove unnecessary toner remaining in the transfer roller when the toner is exhausted as a result of the detection. How to clean. The method of claim 1, wherein the cleaning method of the electrophotographic developer is And a canceling step of releasing the locked state of the cover installed in the electrophotographic developer after performing the decompression step. The cleaning apparatus of the electrophotographic developer which injects the toner onto the electrostatic latent image formed on the photosensitive drum, transfers the visualized image developed by the toner from the transfer roller to the printing paper, and fixes the visualized image transferred to the printing paper with heat and pressure in the fixing unit. In: Toner remaining amount sensor for detecting the remaining amount of the toner to confirm the replacement time of the toner; A transfer voltage adjusting unit controlling a voltage supplied to the transfer roller; A central processing unit for controlling the transfer voltage adjusting unit according to a detection result of the toner remaining amount detecting sensor; The central processing unit is configured to reduce the transfer voltage applied to the transfer roller to a voltage level lower than the surface potential of the photosensitive drum when the residual amount of toner is less than or equal to a preset reference value as a result of the detection by the toner remaining amount detecting sensor. A cleaning apparatus for an electrophotographic developer, characterized in that for controlling an adjusting unit. 4. The cleaning apparatus of claim 3, wherein Further comprising a solenoid for releasing the locking state of the cover mounted to the electrophotographic developer under the control of the central processing unit, And the central processing unit controls the solenoid to operate after the cleaning operation of the transfer roller is performed for a predetermined time.