KR20050069220A - Method for recognizing life of a development unit of wet electrophotographic image forming machine - Google Patents

Abstract

A life detection method for a developing unit of a wet electrophotographic image forming apparatus is disclosed. A life sensing method for a developing unit of a wet electrophotographic image forming apparatus according to the present disclosure includes measuring a time when a voltage is applied to a deposit controller and accumulating and storing the accumulated time at a cumulative deposit time; Measuring image coverage; Calculating an effective deposit time using the cumulative deposit time and picture coverage; And comparing the effective deposit time with a preset limit time. According to this, it is possible to more accurately monitor the amount of sludge generated in the developing unit, thereby improving the reliability of the replacement time of the developing unit, thereby preventing unnecessary replacement of the developing unit is economical.

Description

Method for recognizing life of a development unit of wet electrophotographic image forming machine}

The present invention relates to a life detection method for a developing unit of a wet electrophotographic image forming apparatus, and more particularly, to calculate an effective deposit time and to compare the developing unit with a preset limit time. The present invention relates to a life detection method for a developing unit of a wet electrophotographic image forming apparatus.

In general, a developing unit provided in a wet electrophotographic image forming apparatus using a liquid developer (hereinafter referred to as a 'developer') includes a developing unit main body for forming an appearance of a developing unit, a photosensitive drum provided in the main body, and a plurality of developing units. It includes a roller.

The photosensitive drum forms an electrostatic latent image corresponding to an image to be printed on the surface of the photosensitive drum according to an image signal applied from a laser scanning unit provided in the image forming apparatus.

The plurality of rollers include a developing roller, a deposition controller, a metering roller, and a cleaning roller, and are provided in the developing unit body.

In addition, the developing unit main body is provided with a developer carrying part and a sludge carrying part for accommodating a developer.

The developer carrying portion contains a liquid developer containing toner particles in a concentration of about 12% to 13%, and the toner particles in the developer are charged with +. A predetermined voltage is applied to the developing roller, the deposit roller, and the metering roller, respectively, and a gap is formed between the deposit roller and the developing roller.

In addition, an electric field is formed by the voltage difference applied to the deposit roller and the developing roller, and the positively charged toner particles between the gaps are adsorbed onto the developing roller by the electric field. The toner particles are concentrated at a high speed through the metering roller in contact with the developing roller.

The high concentration wet toner moves to the area exposed by the laser scanning unit while passing through the developing nip where the photosensitive drum and the developing roller come into contact with each other, thereby forming an image on the photosensitive drum.

At this time, the wet toner not developed by the photosensitive drum remains in the developing roller and is cleaned by the cleaning roller.

The wet toner separated from the developing roller by the cleaning roller is accommodated in the sludge carrying part provided in the developing unit.

The accumulated toner is called sludge, and since the sludge is different from the original developer, when a lot of sludge accumulates, the sludge overflows inside the developing unit, contaminating the developer with sludge, and the developer fluidity inside the developer. This can lead to malfunction of the developing unit and deterioration of image quality.

1 is a flow chart showing a conventional method of replacing a developing unit, and shows a method of inferring the amount of sludge generated in the developing unit in a uniform method called the number of prints and replacing the developing unit accordingly.

Referring to the drawings, when a print command is applied from the control unit provided in the image forming apparatus, the developing unit is operated to perform a print job (S10).

The controller counts the number of prints n to be printed (S20).

At this time, the printed number of prints n is accumulated and stored in the total number of prints nt in a memory (S30).

Then, the total number of prints (nt) is compared with the predetermined number of lifetimes (nl) (S40), and if the total number of prints (nt) is larger than the predetermined number of lifetimes (nl), an image forming signal is issued to replace the developing unit. The user is notified through the display unit provided in the device (S50). At this time, the number of lifetimes nl is the number of prints for which the developing unit of the image forming apparatus can perform a print job, and is set on the memory of the controller at an initial value when the image forming apparatus is shipped.

Therefore, the user replaces the developing unit when such a replacement message appears. For example, when the number of life sheets is 10,000, when the number of sheets is 10,000, the replacement message is output to the display unit.

When the series of print jobs is finished, the control unit waits for an input command again (S60).

However, replacing the developing unit in such a manner determines the replacement timing of the developing unit uniformly, overlooking the fact that many errors occur in the sludge depending on the type of image to be printed.

That is, the amount of sludge generated is different when the image printed on the paper occupies the entire paper area and when the image is printed on the paper.

In addition, based on the assumption that a large amount of sludge is generated in the developing unit only by the fact that the number of prints is large, the result of determining the replacement of the developing unit is determined.

 Therefore, replacing the developing unit by simply estimating the amount of sludge generated in the developing unit with only the number of prints becomes uneconomical by replacing the still available developing unit early, and overwhelming the user with the cost of replacing the developing unit. The result is a burden.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has been developed in a developing unit of a wet electrophotographic image forming apparatus of an improved method for informing a user of a replacement time of a developing unit according to an amount of sludge generated in a developing unit. The purpose is to provide a life detection method.

The lifetime detection method for the developing unit of the wet electrophotographic image forming apparatus according to the present invention for achieving the above object is a cumulative deposit by measuring the time the voltage is applied to the deposition controller in the developing unit provided in the image forming apparatus; Accumulating and storing at time; Measuring image coverage; Calculating an effective deposit time using the cumulative deposit time and picture coverage; And comparing the effective deposit time with a preset limit time.

The image coverage is preferably a value obtained by dividing the area of the paper by the area of the laser tote set in the image forming apparatus and the dot count product counting each of the laser totes printed on the paper.

In this case, the predetermined limit time is preferably a time accumulated until the image coverage continues to be zero and the amount of sludge is filled in the sludge bearing portion provided in the developing unit.

The effective deposit time may be a product of the cumulative deposit time and (1-picture coverage).

The comparing may further include displaying on the display unit when the effective deposit time is greater than or equal to the limit time.

The comparing may further include displaying an alarm unit when the effective deposit time is greater than or equal to the limit time.

Hereinafter, a life detection method of a developing unit of a wet electrophotographic image forming apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a schematic view of a developing unit according to an embodiment of the present invention. Reference numeral S denotes sludge and reference numeral L denotes a developer.

Referring to the drawings, the developing unit included in the image forming apparatus includes a developing unit body 21, a photosensitive drum 11 provided on the developing unit body 21, and a plurality of rollers.

The developing unit body 21 includes a developer carrying part 27 and a sludge carrying part 29 in which a developer is accommodated, and a separating partition 25 in the developer carrying part 27 and the sludge carrying part 29. And a developer containing toner particles having a concentration of about 12% to 13%.

The photosensitive drum 11 forms an electrostatic latent image corresponding to an image to be printed on the surface of the photosensitive drum 11 in accordance with an image signal applied from the laser scanning unit 16 provided in the image forming apparatus. On one side of the photosensitive drum 11, there is provided a transfer roller 14 for transferring the image on the photosensitive drum 11 to paper, and the reference numeral P denotes a paper transfer path. In addition, the laser scanning unit 16 is connected to the control unit 18 provided in the image forming apparatus through an electrical signal.

The control unit 18 controls various devices such as the transfer roller 14, the laser scanning unit 16, and the developing unit 50 provided in the image forming apparatus to print an image on paper. In addition, the control unit 18 is connected to the display unit 22 or the alarm unit 24 for receiving a signal from the control unit 18 to inform the replacement of the developing unit 50.

The plurality of rollers includes a developing roller 13, a deposition roller 15, a metering roller 17, and a cleaning roller 19.

The developing roller 13 is a developer conveying member which transfers the developing solution to the photosensitive drum 11 so that the electrostatic latent image is developed as a visible image while rotating while facing the photosensitive drum 11. A constant voltage is applied to the developing roller 13 in order to transfer the developing solution to the photosensitive drum 11.

The depositing controller 15 is installed below the developing roller 13 so as to be spaced apart from the surface of the developing roller 13 by a predetermined distance, and the developing roller 13 has the developer stored in the developer carrying part 27 at an appropriate amount or more. It is a developer attachment member to be attached with. A constant voltage is applied to the depositor 15 so that the developer is charged and transferred to the developing roller 13.

When the developer moves from the depositor 15 to the developing roller 13, a closed circuit is formed between the depositor 15 and the developing roller 13, and a current is applied to the circuit for applying a voltage to the depositor 15. Will flow. The magnitude of the current is changed depending on the amount of developer that is moved from the depositor 15 to the developing roller 13.

The metering roller 17 is a developing roller 13 so that the developer excessively adhered to the developing roller 13 by the deposition controller 15 is always transferred to a nip between the photosensitive member 11 and the developing roller 13. It is a regulating roller that regulates the developer on the surface. A predetermined voltage is also applied to the metering roller 17 so as to perform this regulating action.

The cleaning roller 19 removes the developer remaining in the developing roller 13 after developing the electrostatic latent image of the photosensitive drum 11.

Hereinafter, the operation of the developing unit 50 having the above configuration will be described.

First, the control unit 18 applies a predetermined voltage to the developing roller 13, the deposition roller 15, and the metering roller 17 according to the input signal. The electric field is formed by the voltage difference applied to the deposit roller 15 and the developing roller 13.

The toner particles of the developer in the gap 26 between the developing roller 13 and the deposition controller 15 are absorbed by the developing roller 13 by this electric field. The toner particles are concentrated at a high rate as they pass through the metering roller 17 which is in contact with the developing roller 13.

The high concentration wet toner 23a moves to the area exposed by the laser scanning unit 16 while passing through the developing nip in which the photosensitive drum 11 and the developing roller 13 contact each other, and thus the image 23b is disposed on the photosensitive drum 11. ) Is formed.

At this time, the wet toner 23c not developed by the photosensitive drum 11 remains in the developing roller 13 and is cleaned by the cleaning roller 19.

The wet toner, ie, sludge S, separated from the developing roller 13 by the cleaning roller 19 is accommodated in the sludge carrying part 29 provided in the developing unit 50.

Hereinafter, a method of replacing a developing unit of a wet electrophotographic image forming apparatus according to an embodiment of the present invention will be described with reference to FIGS. 3 is a flowchart illustrating a life detection method of the developing unit illustrated in FIG. 2.

Referring to the drawing, when a printing command is applied from the control unit 18 provided in the image forming apparatus, the developing unit 50 is operated to perform a printing operation (S100).

In addition, the time T when the voltage is applied to the depositor 15 in the developing unit 50 is measured and accumulated and stored at the accumulated deposit time TA (S110).

At this time, the developing unit 50 operates according to the time T when the voltage is applied to the developing roller 13 so that some of the toner 23b moves to the photosensitive drum 11, and the undeveloped wet toner 23c. Is collected by the cleaning roller 19 into the sludge carrying part 29. In other words, the larger the time T is applied to the developing roller 13, the longer the operating time of the developing unit 50 becomes, and thus the amount of sludge S is generated more.

The measured time T is accumulated and stored as a cumulative deposit time TA in a memory on the controller 16. That is, the cumulative deposit time TA is the total time when the developing unit 50 is installed in the image forming apparatus and a voltage is applied to the deposit controller 15 of the developing unit 50.

The image coverage M is measured (S120).

The image coverage (M) is obtained by dividing the area (SP) of the paper by the area (SQ) of the predetermined laser dot in the image forming apparatus and the dot count (N) counting each of the laser dots printed on the paper. Value.

In this case, the laser dot is defined as a point of the minimum unit printed through the image forming apparatus, and the control unit 18 counts how many points are printed on the sheet while the laser dot is printed on the sheet. The total number of times is the dot count (N), so the area (SQ) of the laser dot and the dot count (N) means the total area printed on the printing paper. Therefore, image coverage M means the ratio of the printed area to the printing paper area.

Thereafter, the controller 18 calculates the effective deposit time TE using the cumulative deposit time TA and the image coverage M (S140). In this case, the effective deposit time TE is a product of the cumulative deposit time TA and (1-picture coverage M).

At this time, the effective deposit time TE is proportional to the accumulated amount of sludge. That is, since the amount of accumulated sludge is generated in proportion to the accumulated deposit time TA and the unprinted area 1-M on the paper, the accumulated sludge is eventually received in the sludge carrier 29 at an effective deposit time TE. The amount of accumulated sludge can be known.

The effective deposit time TE is compared with the preset limit time TL (S140).

At this time, the limit time TL is a time accumulated until the image coverage M continues to be printed with a zero value and the amount of sludge is filled in the sludge carrying part 29 provided in the developing unit 50. Becomes That is, the printing process is performed on the entire surface of the paper, and the process of printing on the entire paper area is continued, so that the sludge is filled in the sludge carrying part 29, which is a reference time for replacing the developing unit 50.

In other words, it is possible to know a relative ratio of the amount of sludge generated in the developing unit and the reference amount at which the sludge is filled in the sludge carrying part 29 by the limit time TL and the effective deposit time TE. Therefore, it is possible to inform the replacement time of the developing unit 50 according to the sludge generated in the developing unit 50.

When the effective deposit time TE is greater than or equal to the limit time TL, the display unit 22 or the alarm unit 24 provided in the image forming apparatus displays the replacement of the developing unit 50 (S150). .

When the effective deposit time TE is less than the limit time TL, a series of print jobs are terminated, and the control unit waits for an input command again (S160).

By detecting the life of the developing unit in this way, it is possible to more accurately monitor the amount of sludge generated in the developing unit, thereby improving the reliability of the development unit replacement time.

As described above, the wet electrophotographic image forming apparatus according to the present invention can more accurately monitor the amount of sludge generated in the developing unit, thereby improving the reliability of the replacement time of the developing unit and thereby eliminating unnecessary development units. It is economical because it can prevent replacement.

The present invention is not limited to the above-described specific embodiments, and various modifications can be made by those skilled in the art without departing from the gist of the invention as claimed in the claims. Such changes are intended to fall within the scope of the claims.

1 is a flowchart showing a method of replacing a conventional developing unit;

2 is a schematic view of a developing unit according to an embodiment of the present invention;

3 is a flowchart illustrating a method of replacing a developing unit shown in FIG. 2.

* Description of the symbols for the main parts of the drawings *

11; photosensitive drum 13; developing roller

15; deposit roller 17; metering roller

19; cleaning roller 21; developing unit body

29; sludge support part 22; display unit

50; developing unit

Claims (6)

Measuring a time at which a voltage is applied to the deposit controller in the developing unit included in the image forming apparatus and accumulating and storing the accumulated time at a cumulative deposit time; Measuring image coverage; Calculating an effective deposit time using the cumulative deposit time and picture coverage; And comparing the effective deposit time with a predetermined limit time. The life detection method for a developing unit of a wet electrophotographic image forming apparatus, the method comprising: The method of claim 1, Wherein the image coverage is a value obtained by dividing the area of the paper by the area of the laser tote set in the image forming apparatus and the dot count product counting each of the laser totes printed on the paper. Life detection method for developing unit. The method of claim 2, wherein the preset limit time is Life time for the developing unit of the wet electrophotographic image forming apparatus, wherein the image coverage is accumulated until the value of the sludge is filled in the sludge bearing unit provided in the developing unit by continuing printing with a zero value. Detection method.  The method of claim 1, And said effective deposit time is the product of said cumulative deposit time and (1-image coverage). The life detection method for a developing unit of a wet electrophotographic image forming apparatus. The method of claim 1, wherein the comparing step, And displaying the display unit when the effective deposit time is greater than or equal to the limit time. The life sensing method of the developing unit of the wet electrophotographic image forming apparatus. The method of claim 1, wherein the comparing step, And displaying the alarm unit when the effective deposit time is greater than or equal to the limit time. The life detection method of the developing unit of the wet electrophotographic image forming apparatus.