KR20010026184A - Method and apparatus for driving of fan cooler in the laser printer - Google Patents

Abstract

PURPOSE: A method and an apparatus for driving a cooling fan of a laser printer is provided to maintain constantly an internal temperature of a laser printer by changing a driving time of a cooling fan according to an internal temperature. CONSTITUTION: An internal temperature value of a laser printer is detected by measuring the internal temperature within the laser printer. A predetermined duty value is detected by utilizing the detected internal temperature value. A cooling fan driving pulse with a predetermined period is generated according to the detected duty value. The cooling fan is driven according to the generated cooling fan driving pulse.

Description

Cooling fan driving method of laser printer and device therefor {METHOD AND APPARATUS FOR DRIVING OF FAN COOLER IN THE LASER PRINTER}

The present invention relates to a method of driving a cooling fan of a laser printer and an apparatus thereof, and more particularly to detecting a current temperature in a laser printer and varying a driving state of the cooling fan in response to the detected current temperature. The present invention relates to a method of driving a cooling fan of a laser printer and an apparatus for maintaining a stable temperature so as to maintain an optimum printing quality.

In general, a laser printer as a representative example of an image forming apparatus employing an electrophotographic development system, as shown in Fig. 1, includes a pickup roller 101 and a charging roller 102 for printing predetermined image data on a printing sheet. , An organic photoconductive (OPC) 103, a transfer roller 104, a developing roller 105, a supply roller 106, a fixing unit 107, and an exposure apparatus 108. That is, when the charging roller 102 charged by the high-voltage charging voltage rotates to evenly charge the photosensitive member applied to the outer circumferential surface of the photosensitive drum 103, the photosensitive drum 103 with the light generated by the exposure apparatus 108 is charged. The electrostatic latent image to be printed is formed on the surface. Thereafter, a potential difference is generated between the supply roller 106 supplied with the high voltage supply voltage and the developing roller 105 supplied with a voltage lower than the supply roller 106. Therefore, the negative charge moves from the supply roller 106 to the developing roller 105. Thus, the toner supplied from the developing roller 105 is applied to an electrostatic latent image formed on the surface of the photosensitive drum 103 to form a visible image. The high pressure transfer roller 104 transfers the visible image formed by the toner applied to the surface of the photosensitive drum 103 to the printing paper 109 to be transferred. The visible image transferred to the printing paper 109 is fixed to the printing paper 109 by the high heat and pressure of the heating roller 110 and the pressing roller 111 constituted in the fixing unit 107, thereby completing the printing process.

At this time, the supply voltage, the developing voltage, the transfer voltage, and the charging voltage described above are continuously supplied to the supply roller 106, the developing roller 105, the transfer roller 104, and the charging roller 102 until the printing operation is completed. Supplied. Then, the heating roller 110 in the fixing unit 107 is kept turned on until the printing operation is completed.

Then, a pre-transfer lamp (PTL) 112 is installed between the developing roller 105 and the transfer roller 104 to generate a wavelength of 650 nm generated by the transfer lamp 112 in the photosensitive drum 103. By lowering the potential of the toner applied to the photosensitive drum 103 by scanning the light having the light, the binding force of the toner to the photosensitive drum 103 is reduced to improve the transfer efficiency.

In addition, a cooling fan (not shown) is provided at a predetermined position in the laser printer, and is configured to cool the cabin temperature by discharging the air heated in the laser printer to the outside.

However, according to the conventional cooling fan driving method of the laser printer, the following problem (s) occur.

That is, the conventional laser printer rotates at a constant speed at all times regardless of the cabin temperature in driving the cooling fan, so that the print density is printed thinly when the cabin temperature is low, and the print density is dark when the cabin temperature is high. Print defects such as printing occurred.

In other words, the laser printer is a dye that uses a toner made of fine particles as a dye, and is configured to sequentially perform paper feeding, exposure, development, and fixing. Since the characteristics of the various rollers appear differently depending on the temperature conditions, a large concentration difference occurs at high temperature / room temperature / low temperature.

As a result, in the past, the cooling fan was driven to maintain a constant temperature condition in the cabin. However, by maintaining the driving state of the cooling fan constant regardless of each temperature condition (high temperature / room temperature / low temperature), it is sensitive to temperature changes in the cabin. Can't respond. Therefore, print quality is reduced.

Accordingly, the present invention is to solve such a problem (s), the object of the present invention is to change the operating time of the cooling fan in accordance with the temperature of the cabin of the laser printer, thereby maintaining a constant cabin temperature to achieve the optimum print quality The present invention provides a method for driving a cooling fan of a laser printer.

In addition, another object of the present invention is to provide a cooling fan driving apparatus for performing the cooling fan driving method of the above-mentioned laser printer.

1 is a schematic internal structure diagram of a laser printer employing a general electrophotographic development method,

2 is a schematic block diagram of a laser printer applied to the present invention,

3 is a detailed circuit diagram of a cooling fan driving apparatus according to the present invention;

4 is an operation flowchart illustrating a process of driving a cooling fan according to the present invention;

5 is a diagram illustrating a state where the duty values of the cooling fan driving pulses corresponding to the temperature values in the cabin are stored in a table;

FIG. 6 is an operation waveform diagram illustrating cooling fan drive pulses generated in a microprocessor according to duty values of cooling fan drive pulses detected in response to an in-flight temperature value.

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

201: central processing unit 204: engine controller

205: printer engine 206: microprocessor

208: sensor portion 209: cooling fan drive portion

210: cooling fan 211: thermistor

212: analog-to-digital converter Q1: switching transistor

V1: sensing voltage V2: driving voltage

A feature of the present invention for achieving such an object (s) is an electrophotographic laser printer having a cooling fan for discharging the heated air to the outside: detecting an in-flight temperature value of a laser printer; ; Detect a preset duty value corresponding to the detected in-vehicle temperature value; According to the detected duty value, a cooling fan driving pulse having a predetermined period is generated to drive the cooling fan.

Here, it is preferable to supply a constant voltage to a thermistor whose resistance value is changed in accordance with a cabin temperature change of the laser printer, and to detect the cabin temperature value by using a current value flowing through the thermistor.

In addition, it is preferable to divide the cabin temperature value into a predetermined number, to allocate and store the duty value according to the divided range, and to detect the duty value corresponding to the range included in the detected cabin temperature value.

At this time, the cabin temperature value is divided into five ranges of 10 ° C. or less, 11 ° C. to 20 ° C., 21 ° C. to 30 ° C., 31 ° C. to 40 ° C., and more than 40 ° C .; It is preferable to assign a duty value of 0% (stop), 36%, 43%, 60%, and 100% (continuous drive) to each range.

In particular, the laser printer may be configured to perform a cooling fan driving process from the time at which the laser printer receives the print job command to the time at which the print job is finished.

On the other hand, another feature of the present invention, an electrophotographic development laser printer having a cooling fan for discharging the heated air to the outside, comprising: a sensor unit for detecting the temperature value in the cabin of the laser printer; A microprocessor for varying and outputting a duty value of a driving pulse of a predetermined period for driving the cooling fan according to the in-vehicle temperature value detected by the sensor unit; A cooling fan driving unit which is switched by a driving pulse output from the microprocessor to control a driving state of the cooling fan; The microprocessor stores the duty value of the drive pulse corresponding to the cabin temperature value; Detecting a duty value of a driving pulse corresponding to the detected cabin temperature at the time when the cabin temperature is detected by the sensor unit; It is preferable to generate the driving pulse by applying the detected duty value.

Here, the sensor unit and a sensing voltage source for supplying a sensing voltage of a predetermined level; A thermistor whose resistance is varied according to the temperature in the cabin of the laser printer; Including an analog-to-digital converter that converts the current value of the analog type flowing through the thermistor to the digital value by the sense voltage supplied from the sensing voltage source in response to the resistance value varied according to the temperature value of the laser printer to the microprocessor It is preferable.

In addition, the cooling fan drive unit is controlled for the on-off state by the drive pulse of a predetermined duty value output from the microprocessor, the switching for controlling the open state of the loop in which the driving voltage of the predetermined level is passed to the ground through the cooling fan It is preferable to include a transistor.

In addition, the microprocessor preferably divides the cabin temperature value into a predetermined number, allocates and stores a duty value according to the divided range, and detects a duty value corresponding to a range included in the detected cabin temperature value.

At this time, the cabin temperature value is divided into five ranges of 10 ° C. or less, 11 ° C. to 20 ° C., 21 ° C. to 30 ° C., 31 ° C. to 40 ° C., and more than 40 ° C .; It is preferable to assign a duty value of 0% (stop), 36%, 43%, 60%, and 100% (continuous drive) to each range.

In particular, the laser printer may be configured to control the cooling fan driving state from the time point at which the laser printer receives a print job command to the time point at which the print job is finished.

Hereinafter, exemplary embodiment (s) 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.

2 is a schematic block diagram of a laser printer applied to the present invention, FIG. 3 is a detailed circuit diagram of a cooling fan driving apparatus according to the present invention, and FIG. 4 is performed to perform a cooling fan driving method according to the present invention. An operation flow diagram showing the process is shown, and FIG. 5 is a diagram showing a state where the duty values of the cooling fan driving pulses corresponding to the cabin temperature value are stored in a table, and FIG. 6 is detected corresponding to the cabin temperature value. The operation waveform diagram showing the cooling fan driving pulses generated in the microprocessor according to the duty value of the cooling fan driving pulses is shown.

Referring to Figures 2 and 3 the configuration of the present invention will be described.

The central processing unit 201 generally controls each component block in the printer.

The memory 202 temporarily stores print data transmitted from an application program of a computer.

An operation panel (OPE) 203 includes a display window for arranging a plurality of function keys so that a user can select various functions and displaying an operation state of the printer.

The engine controller 204 transmits / receives various commands and commands to the microprocessor 206 in the printer engine 205 and at the same time performs image processing and address information on temporary data stored in the memory 202. The temporary data information is transmitted to the microprocessor 206, and the various operating states and starting points of the printer engine 205, a power supply state, a timing point, and the like are controlled.

The parallel port 207 is connected to a computer to interface a computer and a printer, and receives print data created by an application program of the computer and temporarily stores it in the memory 202.

The microprocessor 206 in the printer engine 205 generally controls the driving state in the printer engine 205 as shown in FIG. In particular, the microprocessor 206 transmits / receives various commands to the engine controller 204 and controls the cooling fan drive unit 209 according to the in-flight temperature value detected by the sensor unit 208.

The sensor unit 208 detects a temperature value inside the printer engine 205 and transmits the result to the microprocessor 206.

The cooling fan driver 209 controls the driving voltage V2 = 24V to be supplied to the cooling fan 210 under the control of the microprocessor 206, thereby switching the driving state of the cooling fan 210.

The cooling fan 210 is installed at a predetermined position of the laser printer to discharge heated air in the cabin to the outside.

On the other hand, with reference to Figure 3 with respect to the cooling fan drive device according to the invention as follows.

In the sensor unit 208, a thermistor 211 whose resistance value varies depending on the cabin temperature of the laser printer is configured between the sensing voltage (V1 = 5V) terminal and the analog / digital converter 212. An analog-to-digital converter 212 is provided, which digitizes an analog current value supplied through 211 and provides it to the microprocessor 206.

In addition, the cooling fan driver 209 includes a switching transistor Q1 for switching the driving voltage V2 to be supplied to the cooling fan 210 according to the driving control signal supplied from the microprocessor 206.

That is, in the cooling fan driving apparatus as shown in FIG. 3, the resistance value of the thermistor 211 is varied as the cabin temperature is changed, and the current value output from the thermistor 211 is changed by the sensing voltage V1. do. The variable current value is converted into a digital value recognizable by the microprocessor 206 by the analog / digital converter 212, and the microprocessor 206 converts the digital current value converted by the analog / digital converter 212. It receives the input terminal (IN) to sense the current temperature in the cabin.

When the present temperature in the cabin is sensed, the microprocessor 206 generates a cooling fan drive control signal through the output terminal OUT, and the switching transistor Q1 is turned on by the signal to drive voltage V2. The cooling fan drive loop is opened to pass to the ground through the cooling fan 210 and the switching transistor Q1.

Referring to Figures 4 to 6 with respect to the operation of the present invention having such a configuration as follows.

When a print command is received from the computer (S1), the central processing unit 201 communicates with the microprocessor 206 in the printer engine 205 through the engine controller 204, preheating the printer engine 205 and performing a print job. Get ready for

At this time, the microprocessor 206 detects the current temperature value in the cabin through the sensor unit 208 (S2). That is, since the resistance value of the thermistor 211 varies according to the temperature in the cabin, the current value supplied to the analog-to-digital converter 212 via the thermistor 211 as the sensing voltage V1 is supplied to the temperature in the cabin. Correspondingly appear different from each other. As a result, the microprocessor 206 receives the current value digitized by the analog-to-digital converter 212 and detects a temperature value in the cabin corresponding to the current value. At this time, it is preferable to store the temperature value in the cabin corresponding to the current value in the form of a look-up table in advance.

When the current temperature value in the cabin is detected, the microprocessor 206 detects the duty value of the driving fan of the cooling fan 210 corresponding to the detected current temperature value in the cabin based on the temperature table as shown in FIG. 5. (S3).

That is, FIG. 5 shows a state in which the duty value of the driving fan of the cooling fan 210 corresponding to the detected in-vehicle temperature value is divided into five stages as an embodiment for explaining the present invention in more detail.

That is, the cooling fan 210 is stopped when the cabin temperature is within the range of 10 ° C. or less, and the duty value of the driving fan of the cooling fan 210 is 36% when the cabin temperature is within the range of 11 ° C. to 20 ° C. When the temperature value in the cabin is within the range of 21 ° C to 30 ° C, the duty value of the driving fan of the cooling fan 210 is set to 43%, and the temperature is within the range of 31 ° C to 40 ° C. The duty value of the fan 210 driving pulse is set to 60%, and if the temperature value in the cabin exceeds 40 ° C, the duty value of the cooling fan 210 driving pulse is set to 100% to continuously drive the cooling fan 210. Let's do it. In this case, the duty value of the driving pulse of the cooling fan 210 for each temperature is a value determined for a plurality of experiments, and the above-mentioned value is a value defined for convenience of description of the present invention and thus may be changed according to the characteristics of the device. Find out in advance.

When the duty value of the driving pulse is determined through the above process, the microprocessor 206 generates the driving pulse according to the detected duty value (S4). That is, as shown in FIG. 6, when the duty value is 36% based on the driving pulse of 20 ms, the driving time of the cooling fan 210 is 7.2 ms and the stopping time is 12.8. The turn-on time of the switching transistor Q1 in the cooling fan drive unit 209 is controlled to be ㎳. If the duty value is 43%, the driving time of the cooling fan 210 is 8.6 ㎳ and the stop time is 11.4 ㎳. The turn-on time of the switching transistor Q1 in the cooling fan driver 209 is controlled. When the duty value is 60%, the cooling fan driver is configured to have a driving time of 12 ms and a stop time of 8 ms. The turn-on time of the switching transistor Q1 in the 209 is controlled, and if the duty value is 100%, the turn of the switching transistor Q1 in the cooling fan eastern part 209 is driven so that the cooling fan 210 is continuously driven. Control the on time. Here, one cycle of the driving pulse is described as 20 ms, but this may vary depending on the performance of the system.

Thereafter, when the print job is completed (S5), the cooling fan drive control state is released, and then returned to the initial state and waits until the print job command is received.

On the other hand, the cooling fan drive control operation may be set to be operated only when the print job is performed, or may be set to be always operated while the main power is supplied to the laser printer. However, when the laser printer does not perform the printing operation for a predetermined time, it switches to the standby mode. In this case, it is efficient not to perform the cooling fan driving control operation because the cabin temperature is maintained at a low temperature or a normal temperature.

Therefore, the cabin temperature can be maintained at a constant value at all times, thereby providing the optimum print quality.

As described above, although the specific embodiment (s) have been described in the detailed description of the present invention, 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 embodiment (s) but should be defined by the claims below and equivalents thereof.

As a result, according to the method and apparatus for driving a cooling fan of a laser printer according to the present invention, the following advantage (s) occurs.

That is, by varying the driving time of the cooling fan in accordance with the cabin temperature of the laser printer, it is possible to maintain the cabin temperature constant to provide the optimum print quality.

Claims (11)

In the electrophotographic laser printer having a cooling fan for discharging the heated air in the cabin to the outside: Detecting an in-flight temperature value of the laser printer; Detecting a preset duty value corresponding to the detected in-flight temperature value; And And driving a cooling fan by generating a cooling fan driving pulse having a preset period according to the detected duty value. The method of claim 1, wherein the in-flight temperature value detection step, A method of driving a cooling fan of a laser printer, characterized by supplying a constant voltage to a thermistor whose resistance value varies according to a temperature change in the cabin of the laser printer, and detecting the cabin temperature value by using a current value flowing through the thermistor. . The method of claim 1, wherein the duty value detection step comprises: And dividing the cabin temperature value into a predetermined number, assigning and storing the duty value according to the divided range, and detecting the duty value corresponding to the range included in the detected cabin temperature value. How to operate cooling fan of printer. The method of claim 3, wherein The in-plane temperature value is divided into five ranges of 10 ° C. or lower, 11 ° C. to 20 ° C., 21 ° C. to 30 ° C., 31 ° C. to 40 ° C., and more than 40 ° C .; A 0% (stop), 36%, 43%, 60%, and 100% (continuous drive) duty value is assigned to each range, respectively. The method according to any one of claims 1 to 4, And the cooling fan driving process is performed from the time when the laser printer receives a print job command to the time when the print job is finished. In the electrophotographic laser printer having a cooling fan for discharging the heated air in the cabin to the outside: A sensor unit detecting an in-flight temperature value of the laser printer; A microprocessor for varying and outputting a duty value of a driving pulse of a predetermined period for driving the cooling fan according to the in-flight temperature value detected by the sensor unit; And A cooling fan driver configured to switch by a driving pulse output from the microprocessor to control a driving state of the cooling fan; The microprocessor is configured to store a duty value of the drive pulse corresponding to the in-flight temperature value; Detecting a duty value of the driving pulse corresponding to the in-flight temperature value detected at the time when the in-flight temperature value is detected by the sensor unit; Cooling fan drive device of a laser printer, characterized in that for generating the drive pulse by applying the detected duty value. The method of claim 6, wherein the sensor unit, A sensing voltage source for supplying a sensing voltage of a predetermined level; A thermistor whose resistance is varied according to the temperature in the cabin of the laser printer; And Analog / Digital which converts the current value of the analog type flowing through the thermistor into a digital value by supplying the sense voltage supplied from the sensing voltage source to the microprocessor in response to the resistance value which is varied according to the temperature value of the laser printer. Cooling fan drive of the laser printer comprising a transducer. The method of claim 6, wherein the cooling fan drive unit, A laser including a switching transistor for controlling an open state of a loop in which an on-off state is controlled by a driving pulse having a predetermined duty value output from the microprocessor, and a driving voltage of a predetermined level is passed to the ground through a cooling fan. Cooling fan drive in the printer. The method of claim 6, wherein the microprocessor, And dividing the cabin temperature value into a predetermined number, assigning and storing the duty value according to the divided range, and detecting the duty value corresponding to the range included in the detected cabin temperature value. Cooling fan drive in the printer. The method of claim 9, The in-plane temperature value is divided into five ranges of 10 ° C. or lower, 11 ° C. to 20 ° C., 21 ° C. to 30 ° C., 31 ° C. to 40 ° C., and more than 40 ° C .; A cooling fan drive device for a laser printer, characterized in that a duty value of 0% (stop), 36%, 43%, 60%, and 100% (continuous drive) is assigned to each range, respectively. The method of claim 6, And a cooling fan driving state controlled from a time point at which the laser printer receives a print job command to a time point at which the print job ends.