JPS6031172A - Warm-up time forecasting device of copying machine - Google Patents

Abstract

PURPOSE:To execute smoothly and rationally a copying work by deriving a temperature variation rate of a temperature variation start time of a fixing part, and calculating and displaying a warm-up time basing on its value, a control target temperature and an initial temperature. CONSTITUTION:An output of a thermoelectric couple 1 is amplified by an OP amplifier 2, and A/D-converted by an A/D converter 3. Subsequently, its output is inputted to a CPU4. A key input part 5, a display part 6 and a memory 7 are connected to the CPU4. The display part 6 displays a warm-up time when a power source is turned on, etc. The memory 7 contains an ROM for recording a program, and an RAM subjected to battery backup, for storing an initial temperature of a fixing part and a control target temperature, etc. In this state, the control target temperature is set in advance to the memory 7, also the initial temperature is stored in the memory 7, furthermore a temperature which has risen is measured, a temperature variation rate is derived, and the warm-up time is forecast by executing an arithmetic from these values, and displayed on the display part 6.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a copying machine equipped with a heat fixing device, which has a method for making the fixing section reach a control target temperature, such as when the power is turned on or when switching from preheat mode to normal copy mode. The present invention relates to a device that predicts the time to warm up a heat fixing device at the start of control and notifies the operator.

<Prior art> At the start of control for the fuser unit to reach the control target temperature, such as when turning on the power switch of the copying machine or switching from preheat mode to normal copy mode, the operator can adjust the temperature of the fuser unit to fix the temperature. You have to wait for a so-called warm-up time until the temperature reaches a certain temperature and you can make copies. However, since this warm-up time is greatly influenced by the input AC voltage, ambient temperature, temperature of the fixing section, etc., the operator cannot predict how long the operator should wait. Therefore, usually you wait in front of the copier until the warm-up time has elapsed, or you do other work and wait a few minutes to several tens of minutes before turning on the copier. I try to go back to where I am and start copying.

However, having to wait in front of the copier for an unpredictable warm-a-knob time irritates the operator, and having to start copying after several minutes to tens of minutes makes it impossible to copy in the shortest possible time. This is extremely unreasonable and has the disadvantage of causing unnecessary power consumption.

<Object of the Invention> The object of the present invention is to provide a warm-up time prediction device that predicts and informs the operator of the time required for warm-up when entering warm-up, thereby enabling smooth and rational copying operations. Our goal is to provide the following.

<Structure of the Invention> To summarize, the present invention defines the control target temperature of the fixing section in advance in a memory or the like, and detects the initial temperature of the fixing section at the time of starting control for making the fixing section reach the control target temperature. Further, the temperature change rate at the start of the temperature change of the fixing section is determined, and the warm-up time is calculated and displayed based on that value, the control target temperature, and the initial temperature. .

FIG. 1(A) shows a warm-up characteristic diagram when the input voltage is different, and FIG. 1(B) shows a warm-up characteristic diagram when the initial temperature of the fixing section is different.

In the figure, to is the time when the power switch is turned on, the time when switching from preheat mode to normal copying mode and starting energizing the fuser unit, the time when the door switch is turned from open to close, etc. to make the fuser unit reach the control target. Indicates the start point of control. tl, t2, and t3 have AC input voltages of V, respectively.
1, V2, and ■3, and the initial temperature of the fixing section is T1, and the time when the fixing section reaches the temperature of T3 is shown. Also the first
In Figure (B), t4 indicates the point in time when the fixing section reaches a temperature of T3 when the AC input voltage is 2 and the initial temperature of the fixing section is T2. Furthermore, t.

The time from t5 to t5 is a time lag time from when electricity starts to be applied to the fixing section until the temperature sensor of the fixing section detects a temperature rise. Further, from t5 to to is a sampling time for calculating the rate of increase.

In Fig. 1 (A), the input voltage ■ is y3>v2>■1
However, as the input voltage increases, the power consumption in the heater of the fixing section increases by 1, so the warm-up time tw also changes according to the input voltage. As a result, when the control target temperature of the fixing section is T3, the relationship t3<t2<tl is established. Furthermore, when the input voltage is constant, the higher the initial temperature of the fixing section, the shorter the ohm-a-knob time.

Therefore, when T2>Tl, the relationship t4<t2 holds.

On the other hand, in a normal thermal fixing device, especially a heat roller type thermal fixing device, the temperature increase gradient from the time when electricity is started to the fixing section until the control target temperature is reached is approximately linear.

Therefore, after the start of warm-up, for a certain period of time (t5~
By detecting the temperature increase rate at t6), it is possible to predict the warm-up time tw until the target control temperature is reached. That is, the arithmetic expression for predicting the warm-up time tw is as follows.

tw-(t 5-t O)+ ((T3-TO)・(
to-t5))/(θ-To) ・---(11 In Figure 1, if the warm-up time is displayed at the time of to, then (t5-to) on the right side of equation (1) above is
can be 0. Also, if (to-t5) is set in advance to the unit time (1 second), the above equation +1 will become tw-(T3-To)/(θ-T O>-(21). Therefore, t5 It is sufficient to measure the initial temperature TO of the fixing section (TI or T2 in FIG. 1) at the point in time, and measure the temperature (θ) after the fixing section has risen one second later.In other words, the control target temperature T3 is stored in advance in memory. Set it and then
At time 5, the initial temperature T1 is stored in the memory, and then t
The warm amplifier time tW can be predicted by measuring the temperature θ after the rise at time o and calculating the above equation (2) from these values.

<Embodiment> FIG. 2 is a control block diagram of a copying machine according to an embodiment of the present invention. The output of the thermocouple 1 is amplified to an appropriate level by an OP amplifier 2 and A/D converted by an A/D converter 3.

The output is input to CPU4. The CPU 4 is connected to a key input section 5, a display section 6, and a memory 7 installed in the operation section of the copying machine. The key input section 5 includes numeric keys and print switches for inputting the number of copies to be made at one time during multi-copying. The display section 6 displays the number of copies set by the key manual section 5, and the warm-up time when the power is turned on or when switching from the breech mode to the normal copy mode. The memory 7 includes a ROM that stores programs and a battery-backed RAM that stores the initial temperature of the fixing section, control target temperature, etc.
including.

FIG. 3 is a flowchart showing the operation procedure of the copying machine.

When starting control of the fixing unit, such as when turning on the power, step n is first performed.
RA at l (hereinafter step ni is simply referred to as ni).
Clear all M areas. Next, check whether there is a paper jam (n2), and if there is a paper jam, turn on the jam lamp (n3). If not, turn off the jam lamp (n4) and check whether the door switch (not shown) is turned off (n5). If the door switch is on, check again from n2. When the door switch is off, normal warm-up operation begins at n6 or below.

First, the time lag time t5 from when power is applied to the fixing unit until the temperature sensor attached to the fixing unit (thermocouple 1 attached to the fixing roller) detects a temperature rise is stored in RAM.
The timer T assigned to the timer T is preset, and at the same time as timing is started, the heater lamp HL (not shown) is turned on (n6). Subtract 1 from the contents of timer T every 1 second,
When the content becomes 0, the digital output T1 of the A/D converter 3 is stored in the memory M1 allocated to the RAM (n7 to n1O). After one second has passed, the output T2 of the A/D converter 3 is stored in area M2 (nil, n1
2). Next, the difference between area M2 and area M1 is calculated and set as area M4 (n13). Furthermore, the control target temperature of the fixing section is read out from the RAM, and the difference between it and the value stored in the area M1 is calculated and stored in the area M5 (n14
). Note that the fixing unit control target temperature T3 is set in advance in an area M3 allocated to the RAM. Next, divide areas M4 and M5 and set area M6 (n
15). The data set in this area M6 is shown above (
2) This is the warm-up time tw shown in the formula, and this value is displayed on the display unit 6 (n16), and 1 is subtracted every second (n17 to n19). When the data in area M6 becomes 1, it can be considered that the warm-up time of the fixing section is almost completed, so the condition is notified by sounding the buzzer for 1 second (n21 to n23), copy ready lamp (Fig. (not shown) is turned on (n24). At this stage, it enters a standby state. Then, when the print switch PSW (not shown) is pressed in this standby state, the process shifts to a copy cycle (n26).

By the above-described operating procedure, it is possible to inform the operator of the predicted warm amplifier time of the fixing section when the power is turned on or when switching from the preheat mode to the normal copy mode. Note that the initial temperature storage means of the present invention corresponds to the RAM area M1, and the target temperature regulation means corresponds to the ROM area M1.
Corresponds to 3. Further, the warm-up time calculation means corresponds to steps n13 to n15 in the above steps.

In the above embodiment, the warm-up time is predicted at time t6 in FIG. 1, but in order to correct the timing error, nl of the above operating procedure is used.

~n16 may be executed at regular intervals, for example, every 5 seconds. Also, to simplify the explanation, t in Fig. 1
Although the time from 5 to t6 is set to 1 second, it can be set to any time from several microseconds to several seconds depending on the timer configuration of the microcomputer. Further, instead of sampling from t5 to t6 described above, sampling may be performed at a plurality of arbitrary points, and the temperature increase rate may be calculated in response based on the sampling data. Furthermore, as a method of displaying the predicted warm-up time, instead of displaying the calculated predicted time directly on the display, multiple light emitters are used to display the remaining time until the warm-up completion time. Good too. In the example shown in Figure 4, the LED
When l is lit, it indicates that the remaining time is in the 70 seconds range, and when both LEDI and LED2 are lit, it is indicated that the remaining time is in the 60 seconds range. Similarly LED1
- When the LED 6 is lit, it indicates that the remaining time is in the 20 seconds range.

Furthermore, although this invention predicts the warm-up time by calculating the temperature rise rate at the start of warm-up, the temperature rise rate can also be calculated by the human power applied to the fixing section. It is also possible to detect the input voltage at , determine the temperature rise rate, and predict the warm amplifier time from this temperature rise rate.

1 In addition, if the ohm-up or calculation or copying operation is interrupted when the door switch is activated or there is a problem, these are detected at the necessary points on the flowchart shown in Figure 3 above and the operation is restarted from nl. You can also do that.

Furthermore, in the above embodiment, the warm-up time is the time required for the fixing section to reach the control target temperature, but if the photosensitive drum needs to be pre-rotated before copying, the time required for this pre-rotation is The added value becomes the warm-up time. In addition, the first setting temperature state (for example, 2
00°C) to a lower second set temperature (e.g. 180°C).
' If it is time to lower the temperature to C), the rate of temperature change that can be claimed is the rate of temperature decrease. Furthermore, although a memory is used as a means for defining the control target temperature, it may also be defined by the magnitude of the voltage using resistor voltage division, charging voltage to a capacitor, or the like.

<Effects of the Invention> As described above, according to the present invention, the warm-up temperature is calculated by calculation based on the initial temperature of the fixing section at the start of warm-up, the control target temperature of the fixing section, and the temperature change rate at the start of warm-up. Since the warm-up time is predicted, the operator can know the warm-up time when the power is turned on or when switching from the preheat mode to the normal copy mode.

Therefore, even if the operator waits until the state is ready for copying, the waiting time is known, so the operator is not irritated, and if the waiting time is long, the operator can do other work after knowing the waiting time. Therefore, the copying process can be started smoothly, and there is no need for a long period of time from the moment the copy is enabled to the time the copy is actually performed. Therefore, there is an advantage that copying work and other work can proceed smoothly and rationally.

[Brief explanation of the drawing]

FIG. 1 shows a temperature characteristic diagram at the fixing unit 3 for detailed explanation of the present invention, FIG. 1(A) shows an example of the temperature characteristic diagram when the input voltage is different, and FIG. An example of a temperature characteristic diagram when the initial temperatures are different is shown. FIG. 2 shows a control block diagram of the copying machine according to the embodiment of the present invention, and FIG. 3 is a flowchart showing the operating procedure of the control section. Further, FIG. 4 is a diagram showing an example of displaying the warm-up predicted time. Applicant Sharp Co., Ltd. Agent Patent Attorney Hisao Komori 4 Figure 1 (A) T [”C] V3) V2>V+ Figure 1 CB) JP-A-Sho GO-31172 (6)

Claims (1)

[Claims] (1) Initial temperature storage means for storing the initial temperature detected by a temperature sensor attached to the fixing section at the start of control for making the fixing section reach the control target temperature, and target temperature specifying means for specifying the fixing section control target temperature. The rate of temperature change is measured by the temperature sensor when the temperature of the fixing unit starts to change, and the temperature change rate is measured by the temperature sensor, and a warm-up temperature is measured until the state is ready for copying based on the control target temperature, the initial temperature, and the rate of temperature change. A warm-up time prediction device for a copying machine, comprising a warm-up time calculation means for calculating a time, and a means for displaying the warm-up time or a state of change thereof.