JPS61102675A - Electronic copying macine - Google Patents

Abstract

PURPOSE:To suppress the overheating of a fixing heater by allowing the fixing heater to stop operating by a fixing heater control means while inhibiting the fixing heater from starting operation while an exposure lamp is turned on. CONSTITUTION:An output port PH for high temperature setting is held at a level H and reference temperature is set high until copying operation is started and the exposure lamp 3 is turned on to start scanning an original. When the scanning operation is started, the high temperature setting state of the reference temperature is maintained. If the operation of the fixing heater 1 is stopped in the middle of the scanning, the inhibition signal generation output port P1 of a microcomputer 5 is held at the level H and then the operation of the fixing heater 1 is inhibited until the scanning is finished afterward. Further, when the fixing heater 1 is in an operation stop state at the start of scanning, the output port P1 of the microcomputer 5 is held at the level H on the start of scanning to inhibit the start of the operation of the fixing heater 1 until the scanning is finished. When the scanning is completed, the reference temperature is set high and the operation start inhibition state of the fixing heater 1 is reset.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention includes an exposure lamp that irradiates light onto a document, and a fixing heater that heats an unfixed image and fixes it on copy paper.
and an electronic copying device comprising means for detecting the operating state of the exposure lamp, means for detecting the temperature of the fixing heater, and fixing heater control means for controlling the operation of the fixing heater based on detection signals from both of the detection means. Regarding machines.

[Conventional technology]

Conventionally, in the electronic copying machine described above, the operation of the fixing heater has been controlled as described below.

That is, while the exposure lamp is on, the operating state of the fixing heater does not change, that is, any change in the operating state, such as starting or stopping the operation, is prohibited. (For example, see Japanese Utility Model Publication No. 58-53552 or Japanese Unexamined Patent Publication No. 59-137977.) In addition, FIG. The time axis is shown together for comparison with that according to the present invention in the figure.

However, when using the above conventional means, especially when copying continuously, if the fusing heater continues to operate while the exposure lamp is on, the fusing heater becomes overheated and the fusing is not performed properly. There is a risk that this process may not be performed properly, or that power may be wasted, so there is room for improvement.

[Problem that the invention seeks to solve]

In view of the above-mentioned circumstances, an object of the present invention is to suppress overheating of a fixing heater and to prevent unnecessary power consumption.

[Means for solving problems]

A feature of the electronic copying machine according to the present invention is an exposure run.

The fusing heater control means controls the operation of the fusing heater based on the detection signal from the operating state detecting means of the exposure lamp and the temperature detecting means of the fusing heater. The operation is as follows.

[For production]

In other words, in the past, it was thought that the operation of the exposure lamp would be adversely affected when the fuser heater started or stopped, so changes in the operation status of the fuser heater were prohibited while the exposure lamp was on. However, as a result of repeated experiments, it was found that the effect on the exposure lamp when the fixing heater stops operating is relatively small compared to when it starts operating. That is, the amount of voltage increase when the operation is stopped is relatively small, and it is easy to electrically compensate for the voltage increase. On the other hand, when the fusing heater starts operating, a fairly large voltage drop occurs, as well as large fluctuations in current, which requires a complex circuit configuration to electrically compensate for these, and the compensation is not sufficient. It is difficult to do so.

Therefore, based on the above experimental results, the electronic copying machine according to the present invention is controlled so that only the start of operation of the fixing heater, which has a large influence on its operation, is prohibited while the exposure lamp is on.

Isho 〔Example〕 The present invention will be described in detail below based on the drawings.

FIG. 1 shows a control system for a fixing heater (1) in an electronic copying machine. This control system includes a try book (2) which is an example of a switching means for the fixing heater (1), a trigger signal generating means (G) for the try book (2), and a temperature control and exposure lamp for the fixing heater (1). The fixing heater (
It is comprised of fixing heater control means (X) for controlling the operation of step 1).

In the fixing heater control means (X), the fixing heater (1)
A thermistor (an example of a temperature detection means installed nearby)
4) detects the temperature of the fixing heater (1), compares this temperature (TI) with the reference temperature (T, ), and determines the detected temperature (T).
, ) is higher than the reference temperature (Ta), the fixing heater (1
) is stopped, and if the temperature is low, the fixing heater (1) is activated.

The comparison between these two temperatures (ts) and (TA) is based on the detection voltage (vm) obtained according to the impedance change of the thermistor (4) and the reference temperature (TA) obtained by the reference voltage light generation means (E). ) is compared with a reference voltage (VA) corresponding to ) using a comparator (C), which is an example of comparison means. Reference voltage generation means (E
) generates a reference voltage (VA) at point A in response to an 'H' level signal from any of the three output ports (PH), (PM), and (PL) of the microcomputer (5). For example, if the high temperature setting output boat (PM) is at the “H” level, the A
Connect the power supply voltage (DC1) to the point and connect two resistors (RA), (
Generates a reference voltage (VAN) divided by Rt+).
Similarly, when the output capo (PM) is at the "H" level, a reference voltage (V) is generated, and the output capo (PM) is generated.
) is at "H" level, a reference voltage (VAL) is generated.

This reference voltage (VA) and
Power supply voltage (DC1) with resistor (R1) and thermistor (4)
Compare the detected voltage (Vl) divided by and VA )'
At VlO, that is, the detected temperature (TI) is equal to the reference temperature (TA
), the output of the comparator (C) becomes “H”.
” level and stop the operation of the fixing heater (1).

Conversely, when Va<Vm, that is, if the detected temperature (TB) is lower than the reference temperature (TA), the comparator (C)
The fixing heater (1) is operated by setting the output to "Level".

On the other hand, a signal from the switch (6) to the exposure lamp (3) that illuminates the original is sent to the microcomputer (5).
It is entered in °. The inhibit signal generation output port (P+) of the microcomputer (5), which becomes 'H' level when the switch (6), which is an example of the operating state detection means, is energized, is connected to the collector of the transistor (Try). The fuser heater (1) is configured to be prohibited from starting to operate, regardless of whether the fuser heater (1) is turned on or off by a signal from the comparator (C). -(PI) goes "H".

If the transistor (Try) is healthy, the collector of the transistor (Try) becomes L'' level regardless of the output signal from the comparator (C), so that no trigger signal is generated for the triac (2). Therefore, the exposure lamp (3) The fixing heater (1) does not start operating while it is lit.

In addition, the input port (pw
) is connected to the output side of the comparator (C), and if this input port (Pw) is at the 'H' level, it is determined that the fixing heater (1) is not operating.

In addition, the four output ports (
PM), (PM), (PL), and (p+) are controlled so that two or more output ports do not become "H" level at the same time.

Next, the operation of the fixing heater (1) will be explained using the flowchart shown in FIG. 2 and the time chart shown in FIG. 3.

When the main switch is turned on and the power is turned on, the low temperature setting output (PL) of the microcomputer (5)
to “H” level, and medium temperature setting output port cp□
) and high temperature setting output port (P+4) to the "L" level, and fix the fixing heater (1) to the standard temperature (TA).
Set to low temperature. At this time, the fixing heater (1) also starts operating, and the temperature of the fixing heater (1) increases. (Step 1) Until the warm-up of the fusing heater (1) is completed, that is, the fusing heater (1) reaches the reference temperature (TAL) or higher, the fusing heater (1) stops operating, and the microcomputer (5) Input port (
The reference temperature (TA) is set to a low temperature until the voltage (pw) reaches the "H" level. When warm-up is completed, set the medium temperature setting output capacitor (PH) to ``H# level'' and set the reference temperature (TA) to medium temperature. Here, since vA and < vg, the fixing heater (1) is activated again. When the fuser heater (1) starts operating and becomes equal to or higher than the reference temperature (T), the fusing heater (1) stops operating, and the temperature of the fusing heater (1) decreases to the reference temperature (TA).
N), the fixing heater (1) starts operating again. I keep waiting in this state. (S
step 2.3.9) Until the copy operation starts and the exposure lamp (3) lights up to start scanning the original,
Set the high temperature setting output port (P+4) to the "H" level and set the reference temperature (TA) to a high temperature. (Step 3,
4+8) When scanning starts, unless the heater operation is already prohibited, if the fusing heater (1) is in operation, the high temperature of the reference temperature (TA) is maintained until the fusing heater (1) stops operating. Maintain settings.

(Step 4.5, 6.8) If the operation of the fixing heater (1) stops during scanning, set the output port (P,) for generating a prohibition signal of the microcomputer (5) to "H".
level, and thereafter, the start of operation of the fixing heater (1) is prohibited until the scanning is completed.

If the fixing heater (1) is in an inactive state at the start of scanning, the microcomputer (5) generates a prohibition signal at the same time as the start of scanning.
” level and keep the fusing heater (
1) is prohibited from starting. (Ste
p 5, 6.7) When the scan is completed, the reference temperature (
TA) to a high temperature and cancel the state in which the start of operation of the fixing heater (1) is prohibited. Here, the fixing heater (1) starts operating. (Step 4, 8) Furthermore, when the copy operation is completed, set the reference temperature (TA) to medium temperature,
As mentioned above, it enters a standby state. (Step 3.9)
Effects of the invention] As described above, the electronic copying machine according to the present invention has the following effects:
While the exposure lamp is on, the fuser heater is prohibited from starting its operation but is allowed to stop operating. Therefore, due to the voltage drop caused by the start of the fuser heater's operation, the illuminance of the exposure lamp fluctuates and the photoreceptor is affected. uneven exposure may occur,
Alternatively, the fixing heater can continue to operate while sufficiently avoiding the inconvenience that the drive motor speed fluctuates and the copy paper conveyance speed differs from the optical system scanning speed, causing synchronization in the copied image. It is now possible to eliminate fusing failures caused by overheating and the wasteful power consumption caused by such problems. Furthermore, the temperature of the fusing heater can be controlled while the exposure lamp is on, with smaller fluctuations than before for the same set temperature, making it possible to design the overall configuration with more leeway, which improves overall performance. , it has become possible to provide an electronic copying machine that is excellent in terms of copying performance, running cost, and manufacturing.

[Brief explanation of the drawing]

1 to 3 show an embodiment of an electronic copying machine according to the present invention, and FIG. 1 is a circuit diagram of a fixing machine control system;
FIG. 2 is a flow chart of the fixing heater control state, and FIG. 3 is a time chart of the fixing heater control state. Fourth
The figure is a time chart corresponding to FIG. 3 showing the conventional example. (1)...Fusing heater, (3)...Exposure lamp, (4)...Temperature detection means, (6)...
. . . Operating state detection means, (X) . . . Fixing heater control means.

Claims (1)

[Claims] The apparatus includes an exposure lamp that irradiates light onto a document, and a fixing heater that heats an unfixed image and fixes it on copy paper, and further includes means for detecting the operating state of the exposure lamp and means for detecting the temperature of the fixing heater. and a fixing heater control means for controlling the operation of the fixing heater based on the detection signals from both of the detection means, wherein the fixing heater control means controls the operation of the fixing heater while the exposure lamp is on. An electronic copying machine that is controlled so as to allow the fusing heater to stop operating while prohibiting its start.