KR20010028933A - Method for compensating image density of electronic image forming device - Google Patents

Abstract

PURPOSE: A picture concentration compensating method is provided to prevent picture concentration from being dropped by automatically adjusting a development voltage applied to a developer according to a low level of a remaining toner amount. CONSTITUTION: A central processing unit confirms whether a print command is received from an outer machine(S301). Printing is performed in order to record the received print data on a paper(S302). The central processing unit confirms whether the printing is completed(S303). If not, the central processing unit confirms whether a remaining toner amount of a developer is below a predetermined value(S304). If the remaining toner amount of a developer is below the predetermined value, a message "TONER LOW" is displayed(S305). A paper sheet count part counts a print number of papers printed through a printer engine(S306), and the unit detects a low level of the remaining toner amount from a look-up table(S307). The unit checks whether a picture concentration value is in a compensable range(S308). If so, the unit detects a development voltage corresponding to the low level(S309). A development voltage adjusting part boosts up the development voltage in order to supply a development voltage corresponding to the low level(S310).

Description

Image density compensation method of electrophotographic development apparatus {METHOD FOR COMPENSATING IMAGE DENSITY OF ELECTRONIC IMAGE FORMING DEVICE}

The present invention relates to a method for compensating image density of an electrophotographic developing apparatus, and more particularly, by automatically adjusting a developing voltage when a residual amount of toner for converting an electrostatic latent image formed on a photosensitive drum into a visible image is low. An image density compensation method of an electrophotographic developing apparatus for maintaining a printing state.

In general, a printer engine of an electrophotographic developing apparatus employing an electrophotographic developing method such as a copying machine, a printer, a multifunction printer, and the like, is shown in FIG. It consists of a charging roller 2, an organic photoconductive (OPC) 3, a transfer roller 4, a developer 5, a fixing unit 6, and an exposure apparatus 7. That is, when the charging roller 2 charged by the high-voltage charging voltage rotates to evenly charge the photosensitive member formed on the outer circumferential surface of the photosensitive drum 3, the photosensitive drum 3 with charged light generated by the exposure apparatus 7 is charged. The electrostatic latent image to be printed is formed on the surface of the film. Thereafter, the developer 5 to which the high pressure developing voltage is applied forms a visible image by applying toner to the surface of the photosensitive drum 3 on which the electrostatic latent image is formed, and the transfer roller 4 to which the high pressure transfer voltage is applied is applied. The visible image is transferred to the printing paper 8 to be conveyed. The transferred visible image is fixed to the printing paper 8 by the high heat and pressure of the fixing unit 6, thereby completing the printing operation. The charging voltage, the developing voltage, and the transfer voltage are continuously supplied to the charging roller 2, the developer 5, and the transfer roller 4, respectively, until the printing operation is completed.

In addition, in the general electrophotographic developing apparatus, the charging voltage applied to the charging roller 2 is -1.4 [kV], the developing voltage applied to the developing device 5 is -300 [V], and the transfer roller 4 is applied. The transferred voltage is +1.5 [V].

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, and the electrostatic formed by the light emitted from the exposure apparatus 7. The latent image has a potential of 0 [V].

When the printing operation is performed in the electrophotographic developing apparatus as described above, the amount of the toner which forms the electrostatic latent image formed on the photosensitive drum 3 as a visible image is gradually reduced. If the remaining amount of such toner is less than or equal to a predetermined value, a message "TONER LOW" is displayed to allow the user to prepare a new developer.

When the message "TONER LOW" is displayed, the user may shake the developer well and then reinstall it to extend the life of the developer.

In this case, the toner loaded in the developer is mixed evenly, and the sensor detecting the remaining amount of the toner determines that the remaining amount of the toner is more than the preset value, and the message "TONER LOW" is not displayed.

However, if the remaining amount of toner is reduced enough to display the message "TONER LOW", even if the user shakes the developer 5 well and reinstalls it, the developer 5 supplied with the same developing voltage is applied to the photosensitive drum 3 surface. Coating the toner causes a problem that the image density is lowered compared to a state where the remaining amount of toner is sufficient.

This means that when a potential difference occurs between the potentials of the respective rollers, the toner under negative charge is moved from a low voltage level to a high voltage level. The developer 5 and the photosensitive drum 3 having the electrostatic latent image having the same developing voltage are provided. Since the potential difference generated between them is always constant, when the amount of toner loaded in the developer 5 is sufficient, the amount of toner moving from the developer 5 to the electrostatic latent image formed on the surface of the photosensitive drum 3 is always constant.

However, when the remaining amount of toner loaded in the developing device 5 is reduced to the extent that "TONER LOW" is displayed, the amount of toner moved to the photosensitive drum 3 also decreases as compared with a sufficient amount of toner under the same conditions. The image density is reduced.

Accordingly, the present invention has been made to solve such a problem, and an object of the present invention is to prevent the image density from decreasing when the remaining amount of the toner for converting the electrostatic latent image formed on the photosensitive drum into a visible image is low. An image density compensation method of an electrophotographic developing apparatus for automatically adjusting a developing voltage applied to a developing device in accordance with a low level of the present invention.

1 is a structural diagram showing a printer engine of a general electrophotographic developing apparatus;

2 is a schematic block diagram of an electrophotographic developing apparatus for compensating image density according to the present invention;

3 is an operation flowchart for compensating image density in an electrophotographic developing apparatus according to the present invention,

4 is an exemplary view of a look-up table in which a developing voltage adjusted according to a low level of the remaining toner amount is stored.

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

10: central processing unit 11: power conversion unit

12: remaining toner detection unit 13: print count counter

14 memory unit 15 developing voltage control unit

16: engine controller 17: printer engine

A feature of the present invention for achieving the above object is that the surface of the photosensitive drum is charged by the charging roller, the electrostatic latent image is formed on the surface of the photosensitive drum by the exposure apparatus, the electrostatic latent image is visualized by the developer, and the transfer An image density compensation method of an electrophotographic developing apparatus in which an image image is transferred onto a printing sheet by a roller, the method comprising: checking a remaining amount of toner loaded in a developing unit while performing a printing operation for recording print data received from an external device onto a sheet And detecting a low toner remaining low level including the remaining amount of toner when the remaining amount of checked toner is low, and varying a developing voltage value supplied to the developer according to the detected toner remaining low level. .

Preferably, if the remaining amount of checked toner is low, the method further includes the step of counting the number of prints of the paper on which the print data is recorded; The toner remaining low level including the counted number of prints is detected.

At this time, the toner remaining low level is divided into predetermined stages, and the number of prints is divided into a predetermined range in a one-to-one correspondence with a predetermined stage of the toner remaining low level, and the developing voltage supplied to the developer in one-to-one correspondence to a predetermined stage of the low toner remaining low level. The values are separated.

Here, it is preferable that the smaller the remaining amount of toner, the larger the absolute value of the developing voltage value.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the elements of each drawing, it should be noted that the same elements are denoted by the same reference numerals as much as possible even if they are displayed on different drawings. In addition, in the following description there are shown a number of specific details, such as components of the specific circuit, which are provided only to help a more general understanding of the present invention that the present invention may be practiced without these specific details. It is self-evident to those of ordinary knowledge in Esau. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

FIG. 2 is a schematic block diagram of an electrophotographic developing apparatus for compensating image density according to the present invention, and FIG. 3 is an operation flowchart for compensating image density in an electrophotographic developing apparatus according to the present invention. 4 illustrates an example of a look-up table in which a developing voltage adjusted according to a low level of the remaining amount of toner is stored.

Referring to FIG. 2, the central processing unit 10 controls the system as a whole according to a set program. In particular, according to a preferred embodiment of the present invention, the image quality is improved by controlling the components in the electrophotographic developing apparatus to adjust the developing voltage applied to the developing device 5 according to the remaining amount of toner loaded in the developing device 5.

The power converter 11 receives the commercial voltage (110V / 220V) for home use, converts the voltage level required by each component in the electrophotographic developing apparatus, and then controls each component under the control of the central processing unit 10. to provide.

The toner remaining amount detecting unit 12 detects the remaining amount of toner loaded in the developing unit 5 and inputs it to the central processing unit 10.

The print quantity counting unit 13 counts the number of prints from the time when " TONER LOW " occurs because the remaining amount of toner detected by the toner remaining amount detecting unit 12 is less than or equal to a preset value under the control of the central processing unit 10. Count.

The memory unit 14 stores an operation program and a general control program for the central processing unit 10 to control the electrophotographic developing apparatus, and stores data according to program execution. In addition, as shown in Fig. 4, according to a preferred embodiment of the present invention, the developing voltage supplied to the developing unit 5 corresponding to one-to-one correspondence with the toner remaining low level divided into predetermined steps and the toner remaining low level, and the remaining toner remaining The number of prints counted by the print count counter 13 divided into a predetermined range in one-to-one correspondence with a low level is stored in the form of a look-up table. Here, the developing voltage increases as the toner remaining low level increases, that is, as the remaining amount of toner decreases.

The developing voltage adjusting unit 15 adjusts the developing voltage applied to the developing device 5 under the control of the central processing unit 10. That is, the developing voltage adjusting unit 15 is converted by the power converting unit 11 so that the developing voltage according to the low level of the remaining toner amount detected under the control of the central processing unit 10 is applied to the developing unit 5, thereby developing the developing unit 5. Adjust the developing voltage applied to).

The engine controller 16 transmits / receives various commands to the central processing unit 10, and transmits the print engine 17 to the printer engine 17, which is received from an external device and processed. It controls the operation status, start time and power supply status.

The printer engine 17 performs an actual print job of recording print data on a sheet under the control of the engine controller 16.

An operation of the present invention having such a configuration will be described in detail with reference to FIG. 3.

The central processing unit 10 checks whether a print command is received from an external device (S301), and performs a print job of recording the print data received from the external device on a sheet (S302).

The central processing unit 10 checks whether the print job is completed (S303), and if the print job is not completed, checks whether the remaining amount of toner loaded in the developer 5 through the toner remaining amount detection unit 12 is less than or equal to a preset value. In operation S304, when the remaining amount of toner is less than or equal to the preset value, the user displays a "TONER LOW" message to prepare a new developer (S305).

Subsequently, the sheet count counting unit 13 counts the number of sheets of paper to be printed through the printer engine 17 under the control of the central processing unit 10 (S306), and the central processing unit 10 counts the number of sheets of paper. The toner remaining low level corresponding to the number of prints counted in the unit 13 is detected in the look-up table stored in the memory unit 14 (S307).

The central processing unit 10 checks whether the detected toner remaining low level is within a compensable range by adjusting the developing voltage supplied to the developing device 5, that is, the image density is compensable (S308), and the image density is compensated. If possible, the developing voltage corresponding to the low toner remaining level detected in step 307 (S307) is detected (S309) and transmitted to the developing voltage adjusting unit 15.

The developing voltage adjusting unit 15 boosts the developing voltage to supply the developing voltage corresponding to the low toner remaining level when the developing voltage is supplied from the power converter 11 to the developing device 5 (S310).

On the other hand, if it is determined that the low toner remaining low level detected in step 307 (S307) is a range capable of compensating for image density, the central processing unit 10 determines that a developer ( The operation of compensating image density is stopped by adjusting the developing voltage supplied to 5) (S311).

Therefore, when the toner remaining level is at the low level, the developing voltage supplied to the developing device is automatically adjusted to compensate for the image density.

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, according to the image density compensation method of the electrophotographic developing apparatus according to the present invention, the image quality is reduced by automatically adjusting the developing voltage applied to the developer according to the low level of the remaining amount of toner. There is an advantage to improve.

Claims (4)

The surface of the photosensitive drum is charged by a charging roller, an electrostatic latent image is formed on the surface of the photosensitive drum by an exposure apparatus, and the electrostatic latent image is visualized by a developing machine, and a transfer roller is used to transfer the image onto printing paper. In the image density compensation method of an electrophotographic developing apparatus: Checking a remaining amount of toner loaded in the developing device while performing a printing operation of recording print data received from an external device on paper; If the remaining amount of the toner checked is low, detecting a toner remaining low level including the remaining amount of the toner; And varying a developing voltage value supplied to the developing device according to the detected toner remaining low level. The method of claim 1, If the remaining amount of the toner checked is low, counting the number of prints of the paper on which the print data is recorded; And detecting a low level of toner remaining amount including the counted number of prints. 3. The method according to claim 2, wherein the toner remaining low level is divided into predetermined steps, the print quantity is divided into a predetermined range in one-to-one correspondence with a predetermined step of the toner remaining low level, and one to one in a predetermined step of the low toner remaining low level. And a developing voltage value supplied to the developing unit is distinguished from each other. 3. The method of claim 2, wherein the absolute value of the developing voltage value increases as the remaining amount of the toner decreases.