JPS6132876A - Fuser control device of copying machine - Google Patents

Abstract

PURPOSE:To prevent a heat roll from overheat by providing the titled device with a means for detecting the temperature of the heat roll, a means for selecting the setting point of a timer and a power control means and increasing the time-up speed of the timer in accordance with the increase of the temperature of the heat rool when a main power supply is ON. CONSTITUTION:The body 1 of the copying machine is provided with a platen 2, a photosensitive drum 3, a paper tray 4, and a fuser 5. A microprocessor is constituted of a CPU9, a read-only memory (ROM)10, a random access memory (RAM)11, and the timer 12. An ON/OFF power control device 13 supplies or interrupts electric power supplied from a power source 14 to/from a heat lamp 7 in accordance with a control signal outputted from the CPU9. Temperature data for discriminating the existing range of the heat roll 6 when the main power supply switch in the copying machine body 1 is turned on and the set point of the timer 12 which is set up in accordance with said temperature range are stored in the ROM10 or the non-volatile RAM11.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuser control device for a copying machine, and more particularly to a fuser control device for a copying machine that prevents runaway of a heat lamp.

(Prior Art) In a conventional copying machine, a heat button type user includes a heat roll and a heat lamp for heating the heat roll.

Conventionally, in order to detect whether this heat lamp is operating normally or is malfunctioning, the temperature of the heat roll is detected after a certain period of time has passed after the heat lamp is turned on, and the temperature of the heat roll is determined to be at a predetermined level. If the temperature is higher than that, it is normal.
If the temperature was below a predetermined temperature, it was considered a failure.

For example, when a heat lamp is turned on, a timer is turned on, the timer is turned off after a certain period of time, and the temperature of the heat roll at this time is measured with a temperature sensor, thereby detecting heat lamp malfunctions such as filament breakage. was.

(Problems to be Solved by the Invention) The above-described conventional techniques had the following problems.

That is, the set time of the timer used to determine whether the heat lamp is normal or abnormal was constant regardless of the user temperature when the copying machine was turned on. In other words, when you turn on the power when the fuser heat roll of the copier is completely cold, and when you turn on the copier again after a while after using the copier, The set time of the timer was constant regardless of whether the power was turned on while the heat roll was warm.

Therefore, when the main power is turned on while the copier is warming up, the heat lamp is turned on for a certain period of time set by the timer and the heat roll is turned on, using the fuser temperature at this time as the initial value. There was a risk that the heat roll would be overheated. Moreover, if the heat roll overheated, there was a risk that the surface of the heat roll would melt.

The present invention has been made to solve the above-mentioned problems.

(Means and operations for solving the problems) In order to solve the above problems, the present invention provides a heat lamp 21 and a A control device for a user 23 having a heat roll 22 that is heated, at least when the main power is turned on, means 24 for detecting the temperature of the heat roll, means 25 for selecting a set value of a timer 26 according to the humidity, A power control means 27 for controlling the time for supplying power to the heat lamp 21 by the timer 26, and means 28 for determining whether the temperature of the heat roll is higher than a predetermined temperature before or at the time of time-up, The present invention is characterized in that the higher the temperature of the heat roll when the main power is turned on, the faster the timer times up.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

In the figure, 1 indicates the main body of the copying machine. As is well known, the copying machine main body 1 includes a platen 2, a photosensitive drum 3, and a paper tray 4.
and a user 5.

Further, the fuser 5 includes a heat roll 6 and the heat roll 6.
It consists of a heat lamp 7 installed inside the
The heat roll 6 is heated by a heat lamp 7.

8 is a temperature sensor for the heat roll 6, and a humidity sensor 8
The information detected is sent to the CPU 9.

CPU9 is read-only memory (hereinafter abbreviated as ROM)
10. Random access memory (hereinafter abbreviated as RAM)
11 and timer 12 constitute a microprocessor. Here, the timer 12 may be included in the CPU 9, but since it is a component of this embodiment, 'CP
It was written separately from U 9. 13 is an on/off power control device consisting of a relay, etc., which controls power according to the control signal from CPLJ9. l! The power from 14 is supplied to the heat lamp 7 or cut off.

Note that a dotted line a in the copying machine main body 1 indicates a conveyance path for copy paper fed from the paper tray 4.

The ROM 10 or non-volatile RAM 11 stores the temperature range of the heat roll 6 when the main power switch (not shown) of the copying machine body 1 is turned on. Temperature data for judgment and a timer setting value of the timer 12 set corresponding to the area are stored. That is, as shown in FIG. 2, the temperatures of the heat roll 6 when the main power switch of the copying machine main body 1 is turned on are O~Tr, Tt~T2, and T
Temperature data Ts, T2, To, which serve as reference values for determining which of the regions 2 to To it belongs to, and the regions 0 to T
Timer setting values γ, β, and α corresponding to 1, 1 to T2, and T2 to To are stored.

Here, To indicates the control temperature of the heat roll 6 at which copying can be performed normally, and there is a relationship of γ>β>α.

Next, the operation of this embodiment will be explained with reference to FIG. FIG. 3 is a flowchart for explaining the functions of the CPU 9.

First, when the main power switch (not shown) of the copying machine main body 1 is turned on, the CPU 9 starts three functions.

Step S1... The CPU 9 samples the temperature of the heat roll 6 that has been detected by the temperature sensor 8. Then, the initial temperature of the heat roll 6 is detected.

Steps 82, 83, 84... The CPU 9 determines whether the initial temperature of the heat roll 6 is below T1, between Ts and T2, or between T2 and To.

Steps 85, 86, 87...When the temperature of the heat roll 6 is below T1, set the set value γ to the timer 12, and set T1
When the time is from T2 to T2, the set value β is set, and when the time is from T2 to To, the set value α is set. Here, the temperature of the heat roll 6 is the control temperature T.

The lower the temperature of the heat roll 6, the longer it takes to reach the temperature, so as mentioned above, γ>β>α. Further, it is assumed that the timer 12 in this embodiment performs a countdown operation from the set value.

Step S8: Set the timer 12 and start countdown.

Step S9: It is determined whether the temperature of the heat roll 6 has become equal to or higher than the control temperature To. If no, proceed to step 810; if yes, proceed to step 811.

Step S10: It is determined whether the timer 12 has become equal to or less than O. If no, the process returns to step S9; if yes, the process proceeds to step S812.

Step 811: It is determined that the heat lamp 7 is normal, and the timer 12 is reset.

Step S12... Heat lamp 7 is considered to be malfunctioning,
Proceed to fail processing to repair the failure.

As described above, according to this embodiment, the set value of the timer 12 is changed according to the initial temperature of the heat roll 6, and when the main power is turned on while the fuser of the copying machine is warmed, Since the setting value is small, the heat roll 6
The risk of overheating and melting its surface is eliminated. Furthermore, in this state, if the heat lamp 7 is out of order, the timer times up earlier than in the conventional device, so step S10 in FIG. I can do it.

(Effects of the Invention) As is clear from the above description, according to the present invention, the following effects are achieved.

(1) Even if the main power is turned on while the copier's fuser is warm, the heat roll will not overheat.

(2) Heat lamp failure can be detected quickly.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram showing the relationship between the temperature of the heat roll and the timer setting value,
FIG. 3 is a flowchart for explaining the functions of the CPU shown in FIG. 1, and FIG. 4 shows an overall configuration diagram of the present invention. DESCRIPTION OF SYMBOLS 1... Copier main body, 5... User, 6... Heat roll, 7... Heat lamp, 8... Temperature sensor, 9... CPU, 12... Timer, 13...・On/off control device, 14...power supply

Claims (1)

[Claims] (1) A control device for a fuser having a heat lamp and a heat roll heated by the heat lamp, including means for detecting the temperature of the heat roll at least when the main power is turned on, and setting a timer according to the temperature. means for selecting a value; power control means for controlling the time for supplying power to the heat lamp by the timer; and means for determining whether or not the temperature of the heat roll is higher than a predetermined temperature before or at the time of time-up. A fuser control device for a copying machine, characterized in that the higher the heat roll temperature when the main power is turned on, the faster the timer times up.