JPH01260467A - Image forming device - Google Patents

Abstract

PURPOSE:To protect each equipment from a trouble by integrating the analog control circuit of various power sources, a CPU for controlling a sequence, a peripheral digital circuit of the CPU and the voltage amplitude detection means of a line on the same chip and providing a protection means for the equipment which acts with the aid of the voltage amplitude detection means. CONSTITUTION:An ICQ 301 is used, which is obtained by integrating the analog control circuit of various power sources for electrostatic charging, exposing and developing, including the switching regulator of a line input, the CPU Q1 for controlling the sequence, the digital circuit such as a memory and a counter, on the periphery of the CPU and the voltage amplitude detection means of the line on the same chip. The protection means for the equipment which acts with an output from the voltage amplitude detection means of the line is also provided. A multiplexer Q12, an A/D converter and the CPU Q1, etc., constitutes the voltage amplitude detection means of the line. Thus, the detection signals of the voltage amplitude detection means can be easily connected with the CPU and the respective control circuits and each equipment in the device can be appropriately protected.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to image forming apparatuses such as copying machines and printers.

[Conventional technology]

Conventionally, in image forming devices such as copying machines and printers,
Low pressure/exposure/band? U river? “The source is the motor.

It was installed in a completely separate hoard from the sequence controller that controls loads such as solenoids and the power supply.

On the other hand, in order to simplify the circuit, a method has been proposed in which the low voltage, exposure, and charging power sources are controlled by a microcomputer program.

However, the method of controlling this power supply using a microcomputer program is as follows.
There is i and it is not realized.

a. It requires a high-speed, high-performance microcomputer and a complicated program, which is costly.

In other words, the detected power output is A-D converted and input to the microcomputer, and the program performs calculations to generate the control fi signal, so it takes a high-speed processing microcomputer to obtain the required response speed of $+1 It requires a computer, a high-speed, high-precision A-D converter, and a complicated program.

b. The peripheral circuits of the microcomputer, ie, analog circuits such as driver circuits and level conversion circuits, remain as discrete circuits, which does not result in miniaturization and simplification of the plug device.

C8 Recently, in order to make devices smaller and more efficient, switching power supplies have been used instead of conventional series regulators, but their control circuits are very complex and expensive.

[AM to be Solved by the Invention] As mentioned above, the conventional device has the problem that the various power sources are provided on a board separate from the load and the sequence controller, making it impossible to reduce the size and weight of the device. The method of controlling the power supply using a microcomputer program has a problem in that it requires expensive parts.

On the other hand, conventionally, due to too little or too much acid in the line input, there have been accidents such as malfunction or damage to switching power supplies, malfunctions and damage to various control circuits, and many failures with poor reproducibility have occurred in the market. This is an important issue in the maintenance department.

The present invention has been made in view of these problems, and an object of the present invention is to provide an image forming apparatus that can be made small and light, has low cost, and can easily protect each device from accidents caused by excessive or insufficient line input. The purpose is to

(Means for Solving the Problem) In order to achieve the above object, the present invention provides an image forming apparatus with an analog control circuit for various power sources for charging, exposure, and development, including a (+) line input switching regulator. , uses an IC that integrates a CPU for sequence control, digital circuits such as memory and counters around the CPU, and line voltage amplitude detection means on the same chip, and operates based on the output of the line voltage amplitude detection means. Ensure equipment protection measures are in place.

(2) In the configuration of (1) above, input is made to the line voltage amplitude detection means from a part of the line input chip power supply.

[Effect]

With this configuration, most of the control circuits of the image forming apparatus including the power supply control circuit and the CPU can be integrated on the same chip, making the apparatus smaller and lighter.Furthermore, the line voltage amplitude detection means can also be integrated on the same chip. , its detection signal c
pu and each control circuit, and can appropriately protect each device in the device.

〔Example〕

The present invention will be explained below using examples.

FIG. 1 is a diagram showing the configuration of essential parts of an image forming apparatus according to a first embodiment of the present invention.

In the figure, the area inside the 1-point line 31 is a single-chip IC.
That is, integrated circuit Q. 1, and CM is used for the purpose of low power consumption.
It is formed by the OS process.

Ql is a CPU core and includes a memory, a counter, an internal bus, etc.

Comparator Q4. Operational amplifier Q1. The FETTr and the capacitor C0 form an A-D converter under the program control of the CPU, and are used to control the setting voltage of the density adjustment volume VRI, the voltage of the thermistor for temperature detection of the fixing roller, and the output of the light i1 sensor of the fluorescent lamp. Convert analog signals to digital signals.

Timer counter Q +7 + resistor R5 and capacitor C2 form a D-A converter under the program control of the CPU, and its output is distributed and held by analog multiplexer Q +3 to capacitors C3, C4, and Cs, and outputs high voltage for charging. Used for switching, switching the developing DC bias output, and switching the light of fluorescent lamps.

The pulse width modulation circuit (PWM) Q14 controls the pulse width according to this D-A output to adjust the width of the fluorescent lamp.
Change the ratio.

Op amp Q? , Q8 are the D added to the input, respectively.
−A band + applied to the A output and the respective reverse polarity input terminals
The pulse width modulation circuit ('P
W M ) In addition to Q +s and Q +e, it controls the energization time of each converter transformer.

The QIA timer counter generates an AC signal for developing bias. Frequency setting and on/off control by CPU
controlled by.

Figure 4 shows one of the power supplies connected to ICQ301 in Figure 1.
This is an example.

The 5V for ICQ301 power supply converts the line smoothed output to converter transformer T37. switching transistor T
The rectified output of the secondary winding of the converter transformer T31 is obtained by voltage division and isolation by a DC-DC converter consisting of r3 (, 2).
TCQa stabilized to +5V by ao+. It is connected to the power input terminal P 303 of I.

IC(1+o+) is formed using a CMOS process and consumes only a few mA of current. FIG.

In Figure 4, when +5V is supplied to ICQ301,
After resetting the inside of the microcomputer by the reset circuit Q2□, the microcomputer starts controlling according to the program stored in the internal ROM. After a predetermined period of time has elapsed after the reset, Q4. Pulse width modulation circuit (
PWM) to start the PWM output. The output pulse is transmitted to the converter transformer T2. of the switching power supply via the output terminal P302. It is added to the base of the primary side switching transistor TrJo+ of the gate drive transformer T32 of the switching FET Tr+o+ of the primary winding. Output of converter transformer T21 (24V
) is the resistance R,. , , After dividing the voltage to a predetermined ratio with R3o2, the chip Q3° is applied via the terminal P301.

is applied to the input of error amplifier Q42. Error amplification &'
j Q 42 is the input and the group added to the opposite input /
P7T pressure is compared and the output is sent to a pulse width modulation circuit (P7T pressure).
WM) Add to Q4+. Self-help converter transformer T3
The rectified and smoothed output of the secondary winding 1 is connected to the resistor R4o, , R4
02, the signal is divided into predetermined values and input to terminal P306 of ICQ3o+. The input voltage to p:+oa is approximately proportional to the voltage amplitude level of the line input. P. 6 and is internally connected to the large multi-tube I node Q12 of the A-D converter within the chip. The voltage amplitude signal of the A-D converted line input is displayed as an abnormal level by the CPU according to its level.

Measures such as setting the on-width limiter of the output of the pulse width modulation circuit (PWM) and stopping the operation are performed to protect the equipment inside the device.

In my son's example, the multiple breaker Q+2. The A-D converter, CPU, etc. constitute line voltage amplitude detection means.

Next, another embodiment will be briefly described.

(1) Figure 2 shows the configuration of the main part of the second embodiment.The line input detection voltage is connected to the window comparator QJ4.
, compare it with its upper limit value and lower limit value, and calculate the output as CP.
The comparator Q44 is a line voltage amplitude detection means.

As a result, when the line input exceeds a predetermined range, all outputs including the switching regulator are stopped under the instruction of the CPU to protect each device or prevent malfunctions.

(2) Fig. 3 shows the configuration of the main part of the third embodiment, in which the line input detection voltage is input to the comparator Q45, and the reference value of the comparator Q,15 is set to the analog switch Q41.
'! What to switch with, ie line input detection? ``The pressure fluctuation is detected by comparison with multiple values in a time-division manner, and the comparator Q45, analog switch Q46, CPU, etc. constitute line voltage amplitude detection means.

(:1) Figure 5 is an example in which a large capacity electrolytic capacitor or electric double layer capacitor is used as capacitor C302 in Figure 4, and when the voltage at terminal P30G becomes lower than a predetermined value, the power is cut off by the CPU. It determines that the CPU has been activated, switches the CPU to standby mode, cuts off all outputs, and enters electric mode.

(4) In FIG. 6, the capacitor C'+02 is replaced with a battery E 301, which is normally charged via the resistor R4o4 and provides battery backup during a power outage.

It detects whether the line input is on or off using the voltage at terminal P36, backs up the memory of the microcomputer, and makes it possible to memorize jams and abnormal modes.

(5) In addition to the above operations, if the line input recovers to slightly above the lower limit during standby mode, the standby mode will be canceled and restarted according to a predetermined sequence, or if there is an abnormality in the line input, a message will be displayed on the display. It is also possible to improve the reliability of the device by providing comments to the user or by storing line input abnormalities.

〔Effect of the invention〕

As described above, according to the present invention, the image forming apparatus can be made smaller, lighter, and lower in cost, and furthermore, it is possible to easily prevent failures and malfunctions of various devices due to excessive or insufficient line input.

[Brief explanation of the drawing]

Fig. 1 is a main part configuration diagram of the first embodiment in which variations in line input voltage are detected via an analog multiplexer of an A-D converter, and Fig. 2 is a diagram of a second embodiment in which variations in line input terminal are detected by a window comparator. Main part configuration diagram of example, 3rd
The figure is a main part configuration diagram of the third embodiment, which detects fluctuations in line input voltage by comparing it with multiple values in a time-division manner, and Figure 4 shows the input from a part of the chip power supply to the line voltage amplitude detection means. FIG. 5 is a circuit diagram showing an example of backup using a large capacity capacitor when power is cut off, and FIG. 6 is a circuit diagram showing an example of battery backup when power f1 is cut off. In the figure, Ql is the CPU core, Q3゜ is IC, Q4~Q
+o is an operational amplifier or comparator. QI21Q+3 is an analog multiplexer, Ql4~Q
I6 is a pulse width modulation circuit, Q44 is a window comparator, Q45 is a comparator, and Ql6 is an analog switch.

Claims (2)

[Claims] (1) Analog control circuits for various power sources for charging, exposure, and development including line input switching regulators, a CPU for sequence control, digital circuits such as memory and counters around the CPU, and line voltage amplitude detection means What is claimed is: 1. An image forming apparatus comprising: an IC integrated on the same chip; and a protection means for equipment operated by the output of the voltage amplitude detection means of the line. (2) The image forming apparatus according to claim 1, wherein the line voltage amplitude detection means receives input from a part of the line input chip power supply.