JPH0623898B2 - Liquid developer detector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a liquid developer detecting device for detecting the amount of developer in a copying machine using a liquid developer, and in particular, it mixes a plurality of liquids such as toner and developer. Liquid level detection of the developing device used as

[Prior Art] In a PPC copying machine, an electrostatic recording type facsimile, etc., a predetermined electrostatic latent image is formed on a charge carrier such as a photoconductor or electrostatic recording paper, and a developer containing toner is adhered to the latent image. To form a visible image. Therefore, the toner or the like is consumed each time the recording operation is performed.

In the case of a wet type, that is, when the developer is a liquid, the developer is generally formed by mixing two kinds of liquids, a toner liquid and a developer. These liquids are replenished from different containers such as bottles when the developer amount decreases. The determination of the amount of developer is generally performed by detecting the liquid level of the developer using a float switch.

However, when stirring is performed to mix the developing solution and the toner solution, the developer is wavy, and the liquid surface level fluctuates. When waviness occurs, when the amount of developer is near the detection level of the float switch, the output of the float switch alternately outputs the normal liquid level and the abnormal liquid level (low liquid level). Therefore, when the output of the float switch is directly connected to the drive circuit of the toner alarm lamp or the like, the toner alarm lamp or the like blinks. Further, when the output of the float switch is connected to the copy control circuit, it may not be possible to copy.

Therefore, for example, Japanese Patent Application Laid-Open No. 56-81871 discloses that the adverse effect of waving is prevented by determining the liquid level based on the integrated value of the signal output from the float switch.

[Object of the Invention] In a copying machine, for example, when the liquid level of the developer becomes lower than a predetermined level, a warning is first issued to the operator by a display lamp or the like, and the developer is not replenished for a long time, and the developer is not developed. Since the recording quality deteriorates when the liquid level of the agent further decreases, it is desirable to set the machine busy state and prohibit the printing operation.

However, a float switch capable of detecting various liquid levels has a complicated structure and is expensive. Also, when such a float switch is used, it is necessary to install a circuit for eliminating the influence of the waving of the liquid level for each liquid level detection signal.
The control circuit also has a complicated configuration.

Therefore, the present invention eliminates erroneous operation due to waviness of the liquid level, and uses only a single liquid level detection signal to detect a plurality of types of control such as low liquid level warning and machine busy control. It is an object of the present invention to enable implementation and provide a multifunctional device at low cost.

[Structure] In order to achieve the above object, in the present invention, a developer container provided with a liquid developer, a stirring means for stirring the liquid developer in the developer container, and a liquid surface in the developer container. In a liquid developer detecting device having a float switch for detecting the height of the liquid, a logic control means for holding state information and performing processing according to the state at that time, first counting means and second counting means And the logic control means permits periodic counting of the first counting means in the first state when the float switch detects a predetermined liquid level,
In the second state, the periodic counting of the second counting means is permitted, and when the count value of the first counting means reaches the value corresponding to the first time, the first signal is output to output the first signal. The state is switched to the second state, the second signal is output when the count value of the second counting means reaches the value corresponding to the second time, and when the float switch does not detect the predetermined liquid level, First
It is configured to clear the count values of the first counting means and the second counting means by setting to the state of.

[Operation] The first time is set to, for example, one cycle or more of the liquid surface vibration determined by the shape of the stirring blade and the operating conditions. Therefore, for example, when the liquid level of the developer drops to a position slightly higher than the detection height of the float switch and the liquid level vibrates due to the operation of the blades or the like, the float switch detects "low liquid level" and Although the counting of the counting means may start, the float switch detects "normal liquid level" once in the liquid level oscillation cycle, so that the first time before the first time elapses. Since the counting means of is cleared, the first signal is not output.

Further, when the liquid level of the developer is lowered to a position sufficiently lower than the detection height of the float switch, the float switch continues to detect "low liquid level" even if the liquid level is wavy. The counting by the counting means is continuously performed. Then, when the first time has elapsed, the first signal is output and, for example, the no-developer display is turned on. At this time, the information held by the logic control means is further switched from the first state to the second state, and counting by the second counting means is started.

When the developer is not replenished, the second counting means continues counting until the second time elapses, and as a result, the second signal is output. It is determined that the subsequent operation is prohibited.

Thus, for example, even when performing both the display control without the developer and the machine busy control, based on only a single liquid level signal output from the float switch,
Since two types of states are distinguished by the length of the duration of the signal, it is possible to use a float switch with a simple structure, the control circuit configuration is simplified, and malfunctions due to waving of the liquid surface are prevented.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. Referring to FIG. 1 a, the tank 20 of the developing device 15 is provided below the photosensitive drum 7. Toner 20 and developer are supplied to the tank 20 of the developing unit 15 from a toner bottle and a developer bottle (not shown), and a predetermined amount of developer is stored therein. The toner liquid and the developing liquid are stirred by the stirring blade 21 connected to the motor. The developer in the tank 20 is pumped up to the developing electrode 23 by the pump 22, and a part of the developer adheres to the photosensitive drum 7 according to the latent image formed thereon. A float switch 24 detects the amount of the developer in the tank 20.

FIG. 1b is an enlarged view showing the vicinity of the float switch 24 shown in FIG. 1a. Float switch 24 with reference to FIG. 1b
Will be explained. The float 25 floats in the developer 26 and moves up and down along the guide rod 27 according to the liquid level of the developer 26. The guide rod 27 is fixed to the tank 20 with a screw and a nut formed at one end thereof.

Inside the float 25, a magnet is provided at a position facing the guide rod, and inside the guide rod 27, two reed switches SW1 and SW2 are provided at vertically different positions. This float switch 2
Outside of 4, there are two switches S as shown in FIG. 1c.
Three lines are drawn from W1 and SW2. S
W1 is turned on (contact closed) when the height of the float 25 is above the boundary of L1, and turned off (contact opened) when the height is lower than that. SW2 is turned on when the height of the float 25 is below the boundary of L2, and is turned off when the height is higher than that. L1
Is the liquid level upper limit level, and L2 is the liquid level lower limit level. Therefore, the switch SW2 detects "low liquid level" of the developer 26.

FIG. 3 shows a schematic configuration of an electric circuit of the copying machine. Third
Explaining with reference to the drawings, a microcomputer unit CPU for controlling is a microprocessor MPU, a read-only memory ROM storing operation program data and constant data, a read / write memory RAM, a timer, I
/ O port, etc., and various units are connected to this I / O port.

The operation panel unit includes a reading circuit for various key switches and a display drive circuit. The display drive circuit includes a light emitting diode LE1 for displaying "no toner" and a light emitting diode LE for displaying "machine busy".
2 etc. are connected. The solenoid driver unit and the relay driver unit are each composed of a large number of drive circuits for driving various clutch drive solenoids, relays and the like.

Switches such as the float switch 24 are connected to the I / O port through an interface circuit composed of many pull-up resistors and the like.

FIG. 2a shows a schematic operation of the microcomputer unit CPU. This will be described with reference to FIG. 2a. First, when the power is turned on, initialization is performed. That is, in this example, the contents of the stack pointer SP are set to 10F8H, and 81
55 (RAM, timer, I / O port) is set to a predetermined operation mode, the contents of RAM are cleared, and various flags are set to the initial state. Then, the operation of the processing loop including the error check subroutine, the status output subroutine, the display subroutine and the start check subroutine is repeated. The display subroutine is a processing routine for activating a predetermined display device based on the contents of various registers and flags, and the start check subroutine is
This is a processing routine for checking the state of keys on the operation panel and checking if there is an instruction such as print start.

FIG. 2b shows the processing operation of the error check subroutine of FIG. 2a. This will be described with reference to FIG. 2b. This process is a state check process of each unit. That is, there is no pause switch check, OPC (photosensitive drum 7) position counter check, paper feed tray cover check, development drawer check, fuser check, jam check, paper feed tray check, operation switch check, main scan error check, etc. Do it under the conditions
Furthermore, when driving the main motor, timing pulses (output in synchronization with the rotation of the photosensitive drum)
An error check, a toner end check, and a registration timing check are performed, and when the main motor is stopped, a collected toner overcheck, an OPC set check, a heater warmup check, and power supply control are performed.

The toner end check processing operation of FIG. 2b is shown in FIG. 2c. Note that this processing operation is repeatedly executed at predetermined time intervals. A description will be given with reference to FIG. 2c. The toner end check is performed by checking the output level of the developer detector 38. If it is not the toner end, the toner end flag and the toner end busy flag are reset, and the contents of the toner end counter and the toner end busy counter are cleared.

When the float switch 24 (SW2) outputs the "no developer" level, the toner end flag is checked.
At the first time, since the toner end flag is reset to "0", the toner end counter is incremented by one. When the output of the float switch 24 continues to be at the level of no developer, the toner end counter counts up every time this process is performed. When the content of the toner end counter reaches the predetermined value N, the toner end flag is set to "1", and the toner end display (LE1 is lit) is performed in the next check. In this embodiment, the predetermined value N
Is set to a value equivalent to 2 seconds, and this value is R
It is stored in the OM (8355) as constant data.

When the float switch 24 continues to output "no developer" level, the toner end busy counter is incremented by one each time this process is performed. When the content of this counter reaches the predetermined value N2, the toner end busy flag is set to "1" and the machine busy display (LE2 is lit) is performed at the next toner end check. In this embodiment, the predetermined value N2 is set to a value corresponding to 2 seconds, and this time data is stored in the ROM as constant data.

When the amount of the developer, that is, the liquid level is reduced to the vicinity of L2 in FIG. 1b, the output level of the float switch 24 fluctuates with the rotation of the stirring blade 21, but this change is generally periodic, and its cycle is Since the value is close to the operation cycle of the stirring blade 21, after the output level of the float switch 24 becomes "no developer (decrease)", before executing the toner check routine N times, that is, before elapse of 2 seconds. To
Since the output level of the float switch 24 changes to "with developer", the toner end counter is cleared and does not reach N. Therefore, the toner end is not displayed.

When the developer further decreases and the liquid level becomes lower than L2 by the height of the wave, the float switch 24 outputs "no developer (decrease)" even at the peak of the wave when the wave is present. If the "developer present" level is not output even after the elapse of 2 seconds, the value of the toner end counter reaches N (that is, 2 seconds) and the toner end is displayed. Even after the toner end is displayed, if the output of the float switching 24 returns to "with developer", the toner end flag, the toner end busy flag, the toner end counter and the toner end busy counter are cleared, so the display is also cleared. It However, in this case, even if the output of the float switch 24 becomes "no developer" again, the toner end display does not change rapidly until the toner end counter becomes N.

If the toner is not replenished even if the toner end is displayed, the toner end busy counter continues to count up with the toner end flag set to "1", and after a predetermined time (N2) has elapsed, the toner end busy flag is set. Set to display the machine busy. Further, as will be described later, the next print operation is prohibited by setting the toner end busy flag.

FIG. 2d shows the general operation of the status output subroutine of FIG. 2a. This will be described with reference to FIG. 2d. If there is no error such as running out of toner or jam in the error check routine, pressing the print key sets the print flag and starts the copy process. That is, the main motor, exposure lamp, charger 14, transfer /
The separation charger 16 and the like are set on, and a scanner (optical scanning system) start signal is output to the optical system control unit.

The paper feed clutch is turned on to drive the feed roller 10 or 11 to feed the recording paper to the registration roller 12. When the count value of the timing pulse corresponding to the position of the photoconductor drum 7 reaches a predetermined value, the registration roller clutch is turned on to drive the registration roller 12 and finish the sheet feeding. When the paper on which the image is transferred is ejected, the print end flag is set. As a result, in the next status output process, the copy counter is decremented in the case of continuous copy and the copy process is restarted, and the copy process is ended in the case of single copy. Immediately after a jam occurs, the main motor, exposure lamp, charger, etc. are turned off, the optical system is returned to the home position, and the flags related to the copy process are reset (set to the copy prohibited state).

When the toner end counter reaches N and toner end is displayed, the copy counter is cleared and normal processing is continued. That is, even when the continuous copy is set, even if the print start key is pressed thereafter, the single copy operation is performed and the processing is ended. If this state continues for a long time and the toner end busy flag is set to "1", the print start instruction is canceled and the error flag is cleared. When the print start cancel is set, the operation of the print start key switch is invalidated, and the toner end and the machine busy are displayed, and the copy cannot be performed until the toner is replenished.

In the above embodiment, one switch SW of the float switch
Although the operation corresponding to 2 has been explained, another switch S
The same applies to W1. In the above embodiment, the microcomputer counts and discriminates time, but the present invention can be implemented in the same manner as in the embodiment by using a normal logic circuit such as a counter, a comparator and a latch.

[Effects] As described above, according to the present invention, it is determined that the developer needs to be replenished only when the float switch continuously detects the absence of the developer for a predetermined time. Even if an abnormal signal is output from the float switch due to chattering of the switch contacts, the device does not operate abnormally.

Also, for example, even when both the display control without developer and the control of machine busy are performed, based on only a single liquid level signal output from the float switch, the duration of that signal is changed. Since the two types of states are distinguished, a float switch having a simple structure can be used, and the structure of the postnatal circuit can be simplified.

[Brief description of drawings]

1a is a side view showing a schematic structure of a copying machine of one type for carrying out the present invention, FIG. 1b is an enlarged side view showing the vicinity of the float switch 24 of FIG. 1a, and FIG. 1c is a float switch of FIG. 1b. 2 is an equivalent circuit diagram of FIG. 2a, 2b, 2c and 2d are flow charts showing the general operation of the microcomputer unit CPU of FIG. FIG. 3 is a block diagram showing a schematic configuration of an electric circuit of another embodiment of the present invention. 1: Contact glass, 2: Illumination lamp 3: First mirror, 4: Second mirror 5: Third mirror, 6: Fourth mirror 7: Photosensitive drum 8,9: Paper feed cassette 10, 11: Paper feed roller 12: registration roller 13: tip bending roller 14: charging charger, 15: developing device 16: transfer / separation charger 17: transport roller, 18: fixing roller 19: copy tray 20: tank (developer container) 21: stirring blade ( Stirring means) 22: Pump, 23: Development electrode 24: Float switch 25: Float, 26: Developer 27: Guide rod SW1, SW2: Reed switch CPU: Microcomputer unit

Claims (1)

[Claims] 1. A developer container provided with a liquid developer, stirring means for stirring the liquid developer in the developer container, and a float switch for detecting the height of the liquid level in the developer container. In the liquid developer detecting device, the logic control means for holding the state information and performing the processing according to the state at that time, the first counting means and the second counting means are provided, and the logic control means is provided with the float. When the switch detects a predetermined liquid level, the first counting means permits the periodic counting in the first state and the second counting state in the second state.
When the count value of the first counting means is permitted and the count value of the first counting means reaches the value corresponding to the first time, the first signal is output to change from the first state to the second state. The second signal is output when the count value of the second counting means changes to a value corresponding to the second time, and is set to the first state when the float switch does not detect the predetermined liquid level. A liquid developer detecting device, wherein the count values of the first counting means and the second counting means are cleared.