JPH0753093Y2 - Fixing temperature controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a fixing temperature control device capable of switching a fixing temperature in a fixing device used in an electrophotographic printer such as a liquid crystal printer.

[Prior art and its problems]

A temperature detecting element such as a thermistor is arranged on the peripheral surface of the heating roll of the fixing device to detect the peripheral surface temperature, and the peripheral surface of the heating roll is kept at a constant temperature based on the detection output of the temperature detecting element. It is known to be configured to hold. However, such conventional temperature control is performed so as to maintain a constant temperature regardless of whether the image forming apparatus such as a liquid crystal printer is printing or idling. Therefore, unnecessary power is wasted even during idling, and a cooling fan provided for avoiding an increase in internal temperature of the apparatus has a large capacity, resulting in annoying wind noise.

[Purpose of device]

The present invention has been made in view of the above problems, and an object thereof is to provide a fixing temperature control device capable of reducing the average power consumption.

[Key points of device]

According to the present invention, the object is to detect a temperature of a fixing roll, a control unit for controlling the temperature of the fixing roll to a predetermined temperature based on a detection output of the temperature detecting unit, and an external device. And a data receiving unit for receiving print data of the fixing roll, and the control unit responds to the print data received by the data receiving unit and changes the temperature of the fixing roll from the first temperature to the first temperature. When control is performed to change the temperature to a second temperature higher than the temperature, it is determined that all the data in the data receiving unit has been discharged and the end of the printing operation has been completed, and all the data has been discharged and the printing operation has ended. The present invention is achieved by providing a fixing temperature control device characterized in that the temperature of the fixing roll is controlled so as to be changed from the second temperature to the first temperature.

〔Example〕

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

FIG. 1 is a block diagram of a controller used in the fixing control device of the present invention, and FIG. 2 is a time chart showing changes in the peripheral surface temperature of the heating roll controlled by the fixing temperature control device of the present invention. . FIG. 3 is a schematic configuration diagram of a printer to which the fixing device of the present invention is applied.

The printer 1 has a heating roll 3, and when the power is turned on, by energizing the heater 8 provided in the heating roll 3, the peripheral surface of the heating roll 3 is heated. On the other hand, the controller is provided with a microprocessor unit (hereinafter referred to as MPU) 4 having a built-in electronic circuit such as ROM, RAM, input / output port, timer, clock oscillator, and the like. It is embedded. Further, a temperature detecting means such as a thermistor 5 for detecting the peripheral surface temperature of the heating roll 3 is brought into direct contact with the peripheral surface of the heating roll 3 or through a heat conducting member, and the output of the thermistor 5 is, for example, an operational amplifier. Is inputted to the amplifier 6 composed of. Then, a change in the resistance value of the thermistor 5 due to a change in the peripheral surface temperature of the heating roll 3 is converted into a voltage change and further amplified by the amplifier 6. The analog voltage change thus converted is input to the A / D converter 7 provided in the output stage of the amplifier 6 and converted into a digital value here, and the output is the MP value.
It is input to the input port of U4.

The heater 8 is, for example, a triac, diac, SC
It is connected to the power source 10 through the control element 9 such as R and phototriac coupler, and the LED in the control element 9 is the MPU4.
It is configured to blink according to the state of the output port of. The energization of the heater 8 is controlled in response to the blinking of the LED.

The MPU 4 refers to the state of the input port of the A / D converter to which digital digital data is input, and outputs a control signal to the output port connected to the control element 9. As a result, the heater 8 is energized and controlled so that the peripheral surface temperature of the heating roll 3 is controlled to a first set temperature, for example, 150 ° C., and the temperature is kept constant. That is part A in FIG.

The controller has a video I / F unit 12 that supplies an opening / closing drive signal to the liquid crystal shutter head (LCS head) 11, and the opening / closing drive signal generated by the video I / F unit 12 is supplied to the liquid crystal shutter head 11. We are supplying. Further, the MPU 4 controls the I / F unit 12 while synchronizing with the electrophotographic process control. Character data, control data, and other print data related to the printing operation are input to the I / F controller 14 from the host computer 13 provided outside the printer,
The I / F controller 14 exchanges signals with the video I / F unit 12.

When print data is sent from the host computer 13 to the I / F controller 14 by an operator's operation, the control accompanying it is performed by the video under the control of the MPU 4.
It is performed in the I / F section 12. That is, the MPU 4 outputs a control signal to the output port connected to the control element 9 by receiving the data, and the peripheral surface temperature of the heating roll 3 is increased from the first set temperature to the second set temperature higher than that. For example 180 ℃
Control to change to. However, even if the MPU 4 issues a command to perform such control, the peripheral surface temperature of the heating roll 3 does not rise to 180 ° C. at an instant due to the delay in the response, and in reality, B and C of FIG.
It gradually rises with the passage of time as shown in. When the peripheral temperature of the heating roll 3 reaches 165 ° C, the MPU 4 can start printing, that is, READY (Fig. 2).
It is determined that the state has been entered, and a signal indicating “print start possible” is sent via the video I / F unit 12 to the I / F controller 14
Send to. The time indicated by B in FIG. 2 is about 10 seconds, and the time required to receive the print data is about 10 seconds. Therefore, at this time, the reception of the print data is normally completed. If not completed, the I / F controller 14 outputs a print start instruction to the MPU 4 after the completion.

When the I / F controller 14 outputs a print start instruction to the MPU 4 via the video I / F unit 12, the MPU 4 feeds the paper 15 loaded in the paper feed cassette by the paper feed roller 16. Output a control signal. As a result, paper 15 is transported
The paper is fed to the 17 side and temporarily stopped by the standby roll 18. On the other hand, the print data in the I / F controller 14 is
A dot signal is serially sent to the liquid crystal shutter head 11 via the video I / F section. The liquid crystal shutter head 11 opens and closes the liquid crystal shutter array inside according to the dot signal thus sent. Then, the peripheral surface of the photoconductor 2 charged in advance by the charger 18 is exposed to form an electrostatic latent image. Toner is attached to this electrostatic latent image by the developing device 19 to form a toner image on the peripheral surface of the photoconductor 2, and the toner image is re-fed by the standby roll 18 in synchronization with the toner image. It is transferred onto the paper 15 by the transfer device 19. Then, the paper 15 is conveyed to a fixing device having the heating roll 3 and the pressure contact roll 20, and the toner image transferred to the paper 15 is fixed by the fixing device. In addition,
At the time of this transfer, the residual toner remaining on the peripheral surface of the photoconductor 2 due to untransferred is cleaned by the cleaner 21.

By the way, as described above, at the time when the MPU 4 sends a signal indicating “print start possible” to the I / F controller 14 via the video I / F unit 12, the peripheral temperature of the heating roll 3 is still 165. Since the temperature is ° C, the fixing temperature is not actually reached. However, as described above, when the peripheral surface temperature of the heating roll 3 reaches 165 ° C., the I
The / F controller 14 outputs a print start instruction to the MPU 4, and as a result, the paper feed roller 16 turns around and paper feed starts, and the paper 15 is sent by the transport roll 17 and the paper 15 is fed. Detected by the standby switch 23, the paper 15 is temporarily stopped in a state where the leading edge of the paper 15 is in contact with the standby roll 18, and is re-fed in time with the toner image, and then the paper 15 It takes about 10 seconds for the tip of the heating roll to reach the heating roll 3, which is the time indicated by C in FIG. 2, during which the peripheral surface temperature of the heating roll changes from the temperature of 165 ° C. The temperature rises to 180 ° C which is the second set temperature. Therefore, when the temperature of the peripheral surface of the heating roll reaches 165 ° C., which is not actually the fixing-enabling temperature, a signal indicating that printing can be started as if fixing is already possible is sent to the MP
U4 outputs to the I / F controller 14, and in response thereto, the process proceeds, and when the paper 15 reaches the heating roll 3, the temperature of the peripheral surface of the heating roll 3 has already been increased.
Since the temperature is 180 ° C, fixing is sufficiently possible. When the amount of print data is large, the MPU 4 controls to maintain the fixing temperature of 180 ° C., and printing is continued in that state. That is the part D in FIG.

When the print data in the I / F controller 14 is discharged and the printing operation is completed, the MPU 4 changes the peripheral surface temperature of the heating roll 3 from the second set temperature of 180 ° C. to the original first set temperature. Control to return to 150 ° C. This corresponds to part E in FIG. Even when this temperature drops,
As in the case of rising, it does not instantly drop from 180 ° C to 150 ° C, but gradually drops with a certain gradient. Then, when the temperature drops from 165 ° C, the I / F controller
The signal indicating "ready to print" that was output to 14 is released, the status becomes WAIT (Fig. 2), and the temperature drops further.
Change to idling condition at ℃. In addition, when sending and releasing the signal indicating "print start possible", if the rotation control of the cooling fan in the apparatus is performed at high speed, or if switching control is performed so as to reduce it to low speed, the control is performed during idling. Noise from the cooling fan can be reduced and power consumption can be reduced.

The print data is sent again from the host computer 13, and when the I / F controller 14 receives the print data, the same operation as described above is repeated. The state is shown by B ', C', D'in FIG. Incidentally, in FIG.
Is a generic name for sensors such as a standby switch 23 and a paper size detection switch. Similarly, the load 24 is also output to a driver such as a motor for driving the photoconductor 2 and the standby roll 18, for example. The control output for is shown collectively.

FIG. 4 (a) is a flowchart of a program for controlling the fixing temperature written in the ROM in the MPU4.

Immediately after the power of the printer is turned on, the process S ₁ is initialized.
The program then proceeds to process S _2, the I / F controller 14 sets the T180F flag when receiving in or printer print data in continuing the printing operation from the host computer 13, reset it otherwise To do. That is, this process S ₂ is a subroutine, and its detailed flow is shown in FIG. In the figure, first, the judgment J ₁
Then, it is checked whether or not the I / F controller 14 has received data. When setting the T180F flag branches to process S ₃ If the received data is to another set of T150F flag if the
This is reset and it returns. Printer proceeds to decision J ₂ in the absence received data is examined whether during continue printing operation. If it is continuing, the process branches to the process S ₃ to perform the above process. Now proceeds to process S _4. Otherwise, the return to set the T150F flag to reset the T180F flag.

The T180F flag and the T150F flag are flags for determining whether the peripheral surface temperature of the heating roll 3 is 180 ° C., that is, the second set temperature or 150 ° C., that is, the first set temperature, and the RAM of the MPU4. Is provided in a predetermined area. Further, although it may be separately provided for the first set temperature and the second set temperature,
If only one of them is set, for example, it can be determined that the set temperature is the second set temperature when the set is "1" and the first set temperature when the reset is "0".

Returning to FIG. 4A, when the process S ₂ is completed, the process proceeds to the process S ₅ . Here, the data of the port to which the digital data is input from the A / D converter 7 can be read to know the current temperature of the heating roll peripheral surface. Thereafter, the process proceeds to S _6, wherein with reference to data obtained by the processing S ₅ with examining the state of the T180F flag, energizing or energizing the heater 8 to match the temperature at which the flag is requesting It is decided whether or not to cancel, and then the process proceeds to step S ₇ . The detailed flow of this processing S ₇ is shown in FIG. 7C. First, the judgment J ₃ is executed to read the output data of the A / D converter 7, and whether it exceeds a value corresponding to 165 ° C. Is checked, and if not exceeded, process S ₈
Then, the ready flag is reset and the process returns. If exceeded returns sets the ready flag the process proceeds to S ₉ if.

Returns to 4 (a), the process proceeds to decision J ₁₀ for completing the process S ₇ to determine whether the ready flag is set, if it is not set, the finished the necessary processing or the like (not shown) After returning to the processing S ₂ , the same processing is repeated. When set proceeds to decision J _11, it examined here whether there is print instruction from an operator. If no instruction is given, the same routine as when the ready flag is not set is executed and the process S
Return to ₂ . The process proceeds to S ₁₀ if any print instruction, the print processing described above is performed.

[Effect of device]

As described in detail above, according to the present invention, the peripheral surface temperature of the heating roll can be kept low during idling and can be controlled to the proper fixing temperature only during the printing operation, so that the average power consumption can be reduced. The cooling fan provided to avoid the temperature rise inside the printer can also be stopped or operated at low speed during idling, so that the noise generated by the cooling fan can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of a controller used in the fixing temperature control device of the present invention, and FIG. 2 is a time chart showing changes in the peripheral surface temperature of a heating roll controlled by the fixing temperature control device of the present invention. FIG. 4 is a schematic configuration diagram of a printer to which the fixing device of the present invention is applied, and FIGS. 4A to 4C are flowcharts showing a control flow. 3 ... Heating roll, 4 ... MPU, 5 ... Thermistor, 8
...... Heater, 9 ...... Control element, 10 ...... Power supply.

Continuation of the front page (56) Reference JP 63-52170 (JP, A) JP 61-211979 (JP, A) JP 63-144380 (JP, A) JP 63-229478 (JP , A) JP 62-238583 (JP, A) JP 62-206581 (JP, A) JP 62-187874 (JP, A) JP 60-126681 (JP, A) JP 58-217978 (JP, A) JP 58-194052 (JP, A) JP 58-14847 (JP, A) JP 56-36068 (JP, A) JP 63-44832 (JP, A) Actually opened 58-103072 (JP, U) Actually opened 62-164366 (JP, U) Actually opened 64-15249 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A temperature detecting means for detecting the temperature of a fixing roll, a control means for controlling the temperature of the fixing roll to a predetermined temperature based on the detection output of the temperature detecting means, and print data from an external device. A data receiving unit that controls the temperature of the fixing roll from a first temperature to a temperature higher than the first temperature when the data receiving unit receives print data. The temperature of the fixing roll is controlled when the temperature of the fixing roll is controlled to change to the temperature of 2 and all the data in the data receiving unit is discharged and the end of the printing operation is determined and all the data is discharged and the printing operation is completed. Is controlled so as to change from the second temperature to the first temperature.