JPS62269161A - Controller for copying machine using synchronous motor - Google Patents

Abstract

PURPOSE:To prevent fixing performance from deteriorating even if a power source frequency increases by providing a power source frequency detecting means which detects the power source frequency and a timer means which adjusts the interval between one copying process and a next copying process on the basis of the detected frequency. CONSTITUTION:A timer T is assigned to a RAM 12 and set when a print switch PSW arranged on the console panel of a copying machine is pressed. Then it is decided at the end of one copying process whether or not the timer T is in a time-up state and when so, the next process can be entered. Further, the timer time of this timer T is set principally on the basis of the power source frequency detected by an input frequency detecting circuit 16. The timer time is so set longer when the detected frequency increases or shorter when the detected power source frequency decreases.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a control device for a copying machine that rotationally drives a photosensitive drum, a transport roller, a fixing roller, etc. using a synchronous mode.

<Prior Art and Its Disadvantages> Generally, since the heater and motor of the fixing device of a copying machine use a large amount of electric power, alternating current power is directly supplied to the heater lamp and motor.

Conventionally, in such copying machines, capacitor run type induction motors have been exclusively used as motors.

However, in an induction motor, when the load torque increases relative to the rotational speed of the induced rotating magnetic field, slippage increases and the rotational speed tends to decrease. Additionally, when the voltage supplied to the motor decreases, slippage increases even under constant load.
In this case as well, the rotational speed tends to decrease. With this type of induction motor, the rotational speed changes depending on multiple factors, making it difficult to synchronize the leading edge of the paper and the leading edge of the image with high precision, or to perform overlapping copying multiple times on a single sheet of paper. There is an inconvenience. Therefore, it has been proposed to use a relatively inexpensive synchronous motor as the drive motor, which exhibits almost no speed change due to variations in load torque or power supply voltage.

'However, when the frequency of a synchronous motor fluctuates, the rotational speed also fluctuates accordingly, so there was a problem in that the fusing performance in the fusing section, which is controlled at a constant temperature, changed in response to fluctuations in the power supply frequency. . That is, as the power supply frequency increases, the conveyance speed of the paper increases accordingly, resulting in poor fixing performance at the fixing section.

<Object of the Invention> The object of the present invention is to provide a power supply frequency detection means for detecting the power supply frequency and a timer means for adjusting the interval between one copying process and the next copying process based on the detected frequency. An object of the present invention is to provide a control device for a copying machine using a synchronous motor that compensates for fixing followability in a fixing section and makes the number of copies constant.

<Structure and Effects of the Invention> The present invention provides a copying machine in which a rotating body is driven by a synchronous motor, including a timer means that is activated during a copying process and sets the state to enable the next copying process after time-up; A power supply frequency detection means for detecting the power supply frequency of the motor; and a timer time setting means for setting the timer time of the timer means based on the frequency detected by the input frequency detection means. According to the present invention configured as described above, when the power supply frequency fluctuates, the fluctuation is detected by the power supply frequency detection means, and based on the detected power supply frequency, the fluctuation is detected until the next copying process is executed. The interval is adjusted by timer means.

That is, if the timer time setting means is set so that the timer time becomes longer as the power supply frequency becomes higher, the time between two copying processes becomes longer as the power supply frequency becomes higher. Therefore, even if the power supply frequency becomes high, it is possible to prevent the fixing performance from deteriorating.

As described above, according to the present invention, by using a synchronous motor, paper can be conveyed with high accuracy even when there are fluctuations in the power supply voltage or load torque, and even when the power supply frequency fluctuates. Since the time until the next copying process is executed is adjusted according to the fluctuation, it is possible to compensate for the fixing followability, prevent paper from having poor fixation, and reduce the number of copies per short time. This has the advantage that the number of copies per copy can always be kept constant.

<Embodiment> FIG. 2 is a schematic block diagram of a copying machine which is an embodiment of the present invention. The alternating current power supply AC is supplied to a power supply circuit P via a power switch SW and an isolation transformer T, and the voltage converted into a direct current by this power supply circuit P is supplied to a control circuit C. Furthermore, the power supply voltage that has passed through the power switch SW is applied to the heater lamp HL, main motor MM, and fan motor F.
Supplied to M. Heater lamp HL is TRIAC TR
The power supply is controlled by the main motor MM, and the main motor MM is driven when the relay contact X is turned on. This relay contact
normally conducts when the power switch SW is turned on. Further, the main motor MM is composed of a synchronous motor. The fan motor FM is driven when the power switch SW is turned on, and is disposed inside the main body of the copying machine.

FIG. 3 is a block diagram of the control circuit C.

CPUI O contains ROM II which stores the control program for the entire copying machine, and RAM which stores control data, etc.
12, and an input side 110 where the input ports are arranged.
13 and an output side 11014 where an output port is arranged are connected by a bus.

The input side l1013 includes an AC voltage detection circuit 15, an input frequency detection circuit 16 that detects the power supply frequency, an ambient temperature detection circuit 17 that detects the ambient temperature of the copying machine, and a humidity detection circuit 18 that also detects the humidity around the copying machine. , a paper size detection circuit 19 that detects the size of the paper to be conveyed.
, and other input sensors 20 are connected.

The output side 11014 includes an HL drive circuit 21 that drives the heater lamp HL, a paper feed device 22 that feeds paper in the cassette, a motor drive circuit 23 that drives a relay on and off for driving the main motor MM, and a process control element 24 for controlling each element for controlling the copying process, such as a main charger and a transfer charger.

In the above configuration, a timer T is assigned to the RAM 12, and this timer T is set when the print switch PSW arranged on the operation panel of the copying machine is pressed. Then, (2) it is determined whether or not this timer T has timed up at the end of the copying process, and when the timer T has timed up, the next copying process can be started. Further, the timer time of the timer T is set mainly based on the power supply frequency detected by the input frequency detection circuit 16. The timer time is set such that the timer time becomes longer as the detected power supply frequency becomes higher, and the timer time becomes shorter as the detected power supply frequency becomes lower.

FIG. 1 is a flowchart showing the copying machine control procedure stored in the ROM II.

When the power is turned on, first, in step nl (hereinafter, step ni is simply referred to as ni), initial settings of each operating section are performed, and the work area of the RAM 12 is also cleared. Next, at n2, the operator waits for the copying conditions to be input. Copying conditions include, for example, the number of copies to be made and the scale/enlargement ratio.16 Once the necessary copying conditions are input and the lens position and paper cassette are selected in accordance with the input conditions, the print switch PSW is then pressed with n3. Wait for it to be pressed. After waiting for this print switch PSW to be pressed, the timer time is calculated at n4. The timer time T is calculated using the following formula.

T= f (vac) ・g(f) ・h (θ
)・Φ(h)・! (S)・To f (vac): AC input voltage function g (f)
: Input frequency function h (θ) : Ambient temperature function Φ (h) : Ambient humidity function A (S) : Paper size function To : Timer time under rated operating conditions The most important term on the right side of this equation is g ( f). That is,
The input frequency function is the most important, and the timer time T largely depends on this input frequency function g(').In this embodiment, this input frequency function g is used to determine the timer time T.
In addition to (f), four functions are used including the AC input voltage function f(vac). In this way, input frequency function g (
By using the other four functions f), it is possible to set the timer time T to an even more preferable value. For example, as the voltage decreases, the power supplied to the heater lamp HL decreases, so if fixing followability is to be maintained at a constant value, it is preferable to slow down the paper conveyance speed. Also, if the ambient temperature is low, the surface temperature of the fixing roller will also be low, so the paper transport speed should be slowed down.
Shita is better. Therefore, if these functions are also associated with setting the timer time, it becomes possible to set the timer time T to a more appropriate value.

Note that FIG. 4 is a diagram showing the relationship between frequency and timer time. This shows that the higher the frequency, the longer the timer time T. n4 that calculates this timer time corresponds to the timer time setting means of the present invention.

Once the timer time T is calculated as described above, the timer T is then set at n5. After setting the timer T, the process advances to n6 and executes JOBA. JOBA
Then, the main charger MHV arranged around the photosensitive drum is turned on, and the static elimination lamp BL is also turned on.

Furthermore, the paper feed roller is also driven to feed paper from the paper cassette. At step n7, it is determined whether or not a jam occurred while executing CJOBA. If a jam occurs, an error process (not shown) is entered, and the operator removes the jammed paper. If JOBA is executed normally, then JOBB of n8 is entered. In JOBB, a transfer charger THV for transferring the toner image formed on the photosensitive drum to paper is turned on. Then n
In step 9, it is determined whether or not a jam occurred in the paper being transferred. nlO indicates that paper has been ejected to the eject tray.
If it is detected, it goes to nil and executes JOBC. Here, post-processing of the copying process and the like are performed to prepare for executing the next copying process.

Next, at n12, it is determined whether the timer T has timed up. After waiting for the timer T to time up, it is determined in n13 whether all the copying processes have been completed, and if not, steps n4 and subsequent steps are executed again. If the process has ended, the process returns to the state at the beginning of n2.

If the power supply frequency fluctuates due to the above operation, n4't
'The timer time T determined by the calculation also varies. That is, as the power supply frequency becomes higher, the timer time T becomes longer. Therefore, the waiting time at n12 also increases. As the power supply frequency increases, the rotational speed of the main motor MM also increases (as a result, the paper conveyance speed becomes faster.However, as the waiting time at n12 becomes longer, the paper feeding interval is eventually controlled to be constant, and the fixing followability becomes faster. Similarly, in this embodiment, the fixing followability is compensated for variations in voltage, temperature, humidity, and paper size.

As described above, in this embodiment, when the power frequency fluctuates, the timer time automatically changes according to the fluctuation, so even if the power supply frequency changes and the paper conveyance speed changes, the paper feeding period remains constant. Constantly controlled. For this reason, it is possible to compensate for fixation tracking and properties at the fixing section.
Fixing defects can be reliably prevented.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the operation of a control section of a copying machine according to an embodiment of the present invention. FIG. 2 is a block diagram of the copying machine, FIG. 3 is a block diagram of a control circuit, and FIG. 4 is a diagram showing changes in timer time with respect to fluctuations in power supply frequency. MM-main motor (synchronous motor), HL-heater lamp, T-timer.

Claims (1)

[Claims] (1) In a copying machine in which a rotating body is driven by a synchronous motor, a timer means is activated during a copying process and is set to a ready state for the next copying process after a time-out;
A synchronous motor comprising: power supply frequency detection means for detecting the power supply frequency of the synchronous motor; and timer time setting means for setting the timer time of the timer means based on the frequency detected by the input frequency detection means. A copying machine control device using