JPH02251980A - Decision device - Google Patents

Abstract

PURPOSE:To improve the reliability of a circuit and to increase the cost of the device by deciding the mounting of a developing unit on a main body device and whether toner is present or not from the signal inputted to an input terminal. CONSTITUTION:When the toner becomes deficient, a piezoelectric element 17a begins to oscillate gradually, its oscillation becomes continuous oscillation is order, and the oscillation signal of the piezoelectric element 17a is inputted to a CPU 22 through an input terminal 21-2. The CPU 22 displays a no-toner display on a display part and the deficiency of the toner in a developer container is securely detected. When the developing unit 12 is not mounted, in earth line l3 is not connected, so a voltage having the earth level completely is inputted to the INT terminal of the CPU 22 by a pull-down resistance RD and the CPU 22 judges that the developing unit 12 is not mounted and resets a flag. Consequently, the percent defect of the circuit decreases and the reliability of the device is improved.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for determining the presence or absence of a developing device unit used in electrophotographic copying machines and various printers, and the presence or absence of developer in the developing device. Regarding equipment.

[Conventional technology]

2. Description of the Related Art Copying machines and various printers are provided with a developer remaining amount detection device in order to replenish developer to a developing device or to allow an operator to detect a lack of developer.

FIG. 8 is an overall configuration diagram of a developing device including a conventional developer remaining amount detection device. In the figure, the developing device 1 is the photosensitive drum 2.
It is arranged near the zero circumferential surface. The developing roll 3 in the developing device 1 is provided at a position where it rubs against the photosensitive drum 2, and the toner 5 sufficiently stirred by the stirring rod 4 is adsorbed on the side of the developing roll 3. A piezoelectric toner sensor 7 is attached to the lower part of the developer container 6 to detect the amount of remaining toner.

The toner sensor 7 is connected, for example, to a printer controller 8 in a printer shown in FIG. In the figure, 9 is a toner detection circuit that transmits the signal of the toner sensor 7 to CPU10, CPU10 is a central processing unit that includes a ROM that stores a printer control program, a RAM that temporarily stores data to be processed by CPU10, etc., and 11 is a toner detection circuit that transmits a signal from the toner sensor 7 to CPU10. This is a display unit that displays information such as whether there is a remaining amount or not and details of the failure.

An output from a toner sensor 7 that detects the presence or absence of toner in the developing device l is output to a toner detection circuit 9.

When the toner sensor 7 detects the lack of toner, it outputs a rectangular wave signal of, for example, 3.5K)Iz, and this signal is sent to the resistors R1-R3 and the capacitor C, in the toner detection circuit 9.
, C, and the transistor Q outputs a high signal, and the transistors Q, , Q.

Turn on. Therefore, a low level signal is input to the IN terminal of CPU10 as a signal indicating toner shortage. Further, when the toner sensor 7 detects the presence of toner, the output of the rectangular wave signal from the toner sensor 7 is stopped, so that the transistor Ql.

Q2 is turned off and a high signal is output to the IN terminal of CPU10. The CPU 9 displays the presence or absence of the remaining amount of toner on the display section 11 in accordance with the above-mentioned low or high signal input from the IN terminal.

On the other hand, the developing device 1 is configured as a unit to be detachably attached to the main body of the printer apparatus, and needs to be replaced when the color of the developer is changed or when the developer reaches the end of its life. For this reason, the main body of the printer device detects whether this developing device is installed or not.
Control must be performed to prohibit the developing operation (printing operation) when the device is not installed. Conventionally, detection of whether the developing unit 1 is attached or not attached has been carried out as follows.

In other words, when the developing device 1 is installed in the printer main body, the 9th
Terminals 3' and 4' connected to each other on the developing device 1 side shown in the figure.
By connecting the input terminals 3 and 4 of the printer controller 8, the input terminal IN of the CPU10, to which a high signal was input via the pull-up resistor R4 when the developing device 1 was not installed, is connected to the input terminals 3 and 4 of the printer controller 8.
, is determined by inputting a low signal when the developing device 1 is installed.

[Problems with conventional technology]

However, in the above-mentioned developer remaining amount detection device, the toner detection circuit 9 uses a large number of discrete components such as transistors L+, Qz, resistors R3 to R3, and capacitors C, , C, etc., so the defect rate increases. This also causes an increase in the cost of the device. Furthermore, four signal lines are required between the developing device 1 and the printer controller 8, which causes noise generation, and also requires two input ports for the CPU10.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional drawbacks, it is an object of the present invention to provide a discrimination device that improves the reliability of the circuit and does not increase the cost of the device.

[Key points of the invention]

In order to achieve the above object, the present invention provides an image forming apparatus that performs development using toner filled in a developer unit configured to be detachably attached to a main unit. A toner sensor that outputs a pulse signal or a DC signal depending on the presence or absence of toner, a control circuit provided in the main device and provided with an input terminal for the toner sensor output signal, and an electrical connection including an electrical connector. a transmission circuit that transmits the toner sensor output signal, which is applied to a predetermined potential guide when the container is opened, to the input terminal; The present invention is characterized by having a determination means for determining the presence or absence of toner and attachment to the apparatus.

[Example] Hereinafter, a first example of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a perspective view showing a partially broken part of a developing device in, for example, a printer to which the discrimination device of this embodiment is applied, and FIG. 3 is a sectional view of this developing device. In both figures, the developing device 12
A developing sleeve 14 that rubs against the photoreceptor drum 13 and has a built-in magnet roll 14a, a stirring rod 15 that stirs the developer (not shown) stored in the developing container 12', and a developing device that is attracted to the circumferential surface of the sleeve 14. It is comprised of a blade 16 that regulates the height of the developer, and a toner sensor 17 that detects the amount of developer (toner) remaining in the developer container 12'. Further, when replenishing developer (toner) into the developer container 12', the lid 18 provided at the top of the developer container 12' is opened in the direction of the arrow. The developing sleeve 14 has gears 14b, 14
The rotational force from, for example, a main motor of a printer in which the developing unit 12 is used is transmitted to the stirring bar 15 via C and a gear (not shown). Further, the developing device 12 is configured to be detachably attached to the printer housing 19, and when the developing device 12 is placed in the housing 19, the toner sensor 17
The output signal is outputted to the printer control circuit via a plurality of contacts 20 provided on the housing 19.

FIG. 1 (al is a block diagram showing the connection configuration and circuit configuration between the toner sensor 17 and the printer control circuit 21. The toner sensor 17 and the printer control circuit 21 are connected to a power line 11, a signal line 12, and a ground line 2303. It is connected by a main line.From the printer control circuit 21 to the output terminal 21-
A voltage 5■ is supplied to the toner sensor 17 via the L power line 11 and the input terminal 17-1, and the printer control circuit 21 is supplied from the toner sensor 17 via the output terminal 17-2, the signal line 12, and the input terminal 21-2. An output signal indicating the presence or absence of toner, which will be described in detail later, is supplied to the ground terminal 17-3 and the ground wire 1.
3. The toner sensor 17 is connected to the ground of the printer control circuit 21 through the ground terminal 21-3.

The toner sensor 17 is specifically constructed of a circuit shown in FIG.
When the piezoelectric element 17 is stored in the
Since the signal a does not oscillate, a high level signal is output from the output terminal 17-2 via the Darlington circuit 17b. On the other hand, when the amount of toner falls below a predetermined amount, since voltage +5V is supplied to the piezoelectric element 17 via the resistors R+ and Rz, it starts oscillating, and this oscillation signal is amplified by the Darlington circuit 17b and sent from the output terminal 17-2. Printer control circuit 21
This is the configuration that is output to.

The printer control circuit 21 includes a CPU <central processing unit) 22 to which the above oscillation signal and high level are input, and a pull-down resistor R.
9 and a power terminal 23 for supplying +5V voltage to the toner sensor 17.

Although the CPU 22 is a central processing unit (not shown) that performs overall control of the printer, only the circuits related to the present invention will be described in this embodiment. FIG. 1(C) is a diagram showing only a part of the circuit configuration within the CPU 22, and shows the interrupt input terminal INT.
The circuit configuration inside the CPU 22 connected to the CPU 22 is shown. When the aforementioned oscillation signal is input via the interrupt input terminal INT and the buffer 24, the CPU 22 detects the fall of the oscillation signal and determines that the interrupt signal IRQTS has been input. In addition, the above-mentioned high level signal or the low level signal of the ground level due to the pull-down resistor R is outputted at a predetermined period by the boat enable signal PE.
5 to the data bus 26 in the CPU 22 as port data PD.

In the determination device having the above configuration, the processing for detecting the remaining amount of developer in the developing device 12 and the processing for detecting whether or not the developing device 12 is installed will be described below.

First, when there is sufficient toner in the developer container 12', the piezoelectric element 17a does not oscillate due to the pressure of the toner, so the Darlington is Depending on the predetermined voltage input to the circuit 17b, the output (out) of the Darlington circuit 17b,
That is, a high signal of +5■ is sent from the output terminal 17-2 of the toner sensor 17 via the signal line 12 to the INT of the CPU 22.
Output to terminal. A signal waveform diagram showing the signal input state of the CPtJ22 at this time is A in FIG. In this case,
Since it is not an oscillation signal, no interrupt based on the oscillation signal occurs (step 1-32 in Fig. 5 (hereinafter denoted by S)).
But no (N)). The high level signal (voltage +5V) input to the CPU 22 is input to the FET 25 via the buffer 24, and the boat enable signal PE is output at a predetermined period.
The data is output to the data bus 26 within the CPU 22 as port data PD (S3). When a high level signal is input as the port data PD in synchronization with the output of the port enable signal PE, the CPU 22 determines that there is sufficient toner in the developer container 12' (S4 is Y), the CPU 2
Reset the toner (TNR) flag in 2 (S5)
.

On the other hand, the toner gradually decreases due to the printing operation, and when the toner becomes depleted, the piezoelectric element 17a gradually starts oscillating. The oscillation changes from a one-shot state to a continuous oscillation as the amount of toner decreases. Therefore, the oscillation signal of the piezoelectric element 17a is transmitted from the Darlington circuit 17b through the output terminal 17-2→signal line β2-input terminal 21-2.
It is output to PU22. At this time, the oscillation signal input to the CPU 22 is in the state shown in B in FIG. In this case, by detecting the fall of the input oscillation signal, the CPU 22 determines that there is an interrupt signal (S2 is Y), and determines whether this signal is an interrupt signal indicating no toner (S6). This determination is made because the CPU 22 has other interrupt input terminals (not shown) and also inputs other interrupt signals indicating toner shortage.
This is a judgment to confirm this, and if the interrupt signal is other than toner shortage, the CPU 22 executes the corresponding interrupt process (S6 is N, S7).

On the other hand, if it is determined that the oscillation signal (interrupt signal) is output from the toner sensor 17 indicating toner shortage, the CPU
22 is a count value N of a counter (not shown) in the CPU 22
It is determined whether or not is "0" (S8). However, the counter is set to "0" at the beginning, and this initial judgment (
S8) becomes Y. Thereafter, the count value N is set to "1" and at the same time, a timer (not shown) in the CPU 22 is started (S9). Thereafter, after a wait time tz (this wait time t2 is 390 μs or more) has elapsed, the printer returns to the normal printing state (Sl). When toner is deficient, a pulse signal is input every time t (based on the oscillation frequency of the toner sensor, time t is 390 μs or less) as shown in B in Figure 4. Similar decisions 52-36-38 are performed. In this case, since the count value N is "1", the judgment (S8) is N, the count value N is +1, and it is judged whether the count value N has become 255 (S11.512) (this count value is , the predetermined time (0, 1
s)). As mentioned above, the count value N is "1" at this time, so the judgment (
312) is N, and the timer time t is 0.
It is determined whether it has been counted for 1 s or more (313), and then the above-mentioned process (SIO) is executed. The above processing (SIO-31-
32→...-512→513) 255 times, for example, as mentioned above, at the beginning of toner shortage, a single pulse signal is output at first, so in such a case, the count value N will be 255 times. The timer clocks the set time (0, 1s) before counting above, and the judgment (S13) becomes Y, so the count value N and timer time t that have been counted up to that point must be reset (314)
, the CPU 22 does not determine that there is no toner.

On the other hand, when it becomes certain that there is a shortage of toner in the developer container 12', a pulse signal is reliably input at the period of time t shown in B in FIG. Since the value N exceeds 225, the CPU 22 determines that there is no toner and sets a toner flag (S12 is YSS1
5). At the same time as setting the toner flag, the CPU 22 displays a toner-free display on a display section (not shown), and then resets the count value N and timer time t to "0" (S14).
). By performing the processing as described above, the shortage of toner in the developer container 12' can be reliably detected.

On the other hand, the state in which the developing device 12 is not installed can be detected as follows. That is, when the developing device 12 is not installed,
Since the ground line 13 is not connected, a completely ground level voltage is input to the INT terminal of the CPU 22 by the pull-down resistor Ro (C in FIG. 4 indicates the voltage level in this state).

The CPU 22 outputs the boat enable signal PE at a predetermined period, and executes processing (S3) and judgment (S4). At this time, since the ground level voltage is applied to the data bus 26, the determination (S4) is N, and the CPU 22
2 is not installed, and the toner unit (TU)
The flag is reset (S16). At the same time, CPU22
Displays on a display section (not shown) that the developing device 12 is not installed.

As described above, in this embodiment, the toner sensor 17 and the printer control circuit 21 are connected by three lines, and the CPU 22
By using the interrupt terminal INT as an input port, it is determined whether there is toner or not and whether the developing device 12 is installed or not.

Next, a second embodiment of the present invention will be described.

The circuit configuration of this embodiment is almost the same as that shown in FIGS. 1(a) and 1(b) above, but the terminal of the CPU 22 to which the output signal (oscillation signal, high level signal, ground level signal) from the toner sensor 17 is input. The difference is that is not an interrupt terminal INT but a normal input terminal (input port). FIG. 6 is a processing flow of the CPU for determining the presence or absence of toner and whether the developing unit 12 is attached or not attached in this embodiment.

First, in the process (step (hereinafter referred to as ST)) (2), the count values M and HSL of the counters m, h, and β are set to 10", and for example, the oscillation period t1 at the time of toner shortage is 300 μsec.
The output of the toner sensor 17 is sampled (S
r2). After that, the count value M of the counter M is incremented by 1, and it is determined whether the count value M is 6" or exceeds 6 (S
r3゜5T4). In the first process (Sr1), since M=1 (Sr1 is N (no)), judgment ST5 is executed.

This judgment is to judge whether the output signal of the toner sensor 17 inputted from the input port of the CPU 22 is high level or low level.If the output signal of the toner sensor 17 at the time of sampling is high level, the count value H of the counter h
+IL (Sr1 is H', 5T6), toner sensor 17
If the output signal of is at low level, the count value of the counter β is increased by 1 (Sr1 is L', 5T7). After a waiting time of 50 μsec (Sr8), the above process (
Sr2-5T8) is repeated 5 more times. Then, when the count value M of the counter m becomes "6" or more, it is determined whether the count value H of the h counter is "0" and whether the count value of the β count is "0" or not. Execute judgment (Sr1.5TIO). That is, the toner sensor 17
The output signals are taken in six times at intervals of 50.17 seconds from then on, and it is determined whether the output signals are all high level or all low level. Then, when all the output signals are at low level (count value I] is "0"), it is determined that the state C in FIG.
). Also, when all the output signals are high level (count value @0''), it is determined that the state is A in Figure 4, and the TU
Cent the flag (SrI2) (at this time, T
(reset the NR flag).

Also, if the six sampling output signals include high and low levels, it is determined that the state is B in Figure 4, the TNR flag is set, and a display (not shown) indicates that there is no toner. Display is performed (ST13). Incidentally, at this time, the TU flag is set at the same time.

As described above, in this embodiment, the presence or absence of toner and whether the developing device 12 is installed or not can be determined without using the interrupt terminal INT.

Next, a third embodiment of the present invention will be described. FIG. 7 is a circuit block diagram of this embodiment. In the figure, the printer control circuit 27 includes a CPU 28 incorporating an analog/digital converter (hereinafter referred to as an A/D converter) 28a, a smoothing circuit 29, a pull-down resistor RD, and a power supply terminal 30.

The function of the pull-down resistor R, and the voltage H terminal 30 is as described above.
This is the same as in Figure (a). However, in this embodiment, the output signal of the toner sensor 17 is output to the smoothing circuit 29 before being supplied to the CPO 28, and the output signal of the toner sensor 17 is smoothed and an analog signal according to the signal components included in the output signal is sent to the CPU 28. is output to the A/D converter 28a.

With the above configuration, when the output signal of the toner sensor 17 is a high level signal (state A in FIG. 4), a DC voltage of, for example, 3°5 or more is applied to the A/D converter 28a from the smoothing circuit 29. toner sensor 17
When the output signal of the toner sensor I7 is an oscillation signal (shape B in FIG. 4), a DC voltage of, for example, 2 to 3 cm is supplied from the smoothing circuit 29 to the A/D converter 28a, and the output signal of the toner sensor I7 becomes a low signal (shape B in FIG. 4). At the ground level state (C in the fourth part), Ov is supplied from the smoothing circuit 29 to the A/D converter 28a. The CPU 28 can determine the presence or absence of toner and whether the developing unit 12 is attached or not attached in real time according to the respective voltages inputted to the A/D converter 28a.

Note that in the third embodiment, the smoothing circuit 29 is not used, and the CP having the built-in A/D converter 28a is directly used.
The configuration may be such that the output signal of the U28 hetoner sensor 17 is input. In this configuration, the toner sensor 17
The output signal (output voltage) is in the range between θ and 5■,
Moreover, since the oscillation signal of toner fiL[ has a period of high level and low level for more than 100 μs, the sampling period of the A/D conversion value is set to about 30 μs, and for example, sampling is performed 10 times in a row, and all 10 data are 3 If it is .5v or more, there is toner, and if both 1o data and 1.0V are below, "developing unit 12 is absent".If 2v or less and 3.5v or more of the 10 data are equal to or higher than Edata, it can be determined that there is "no toner". .

It goes without saying that appropriate values can be selected for the timer setting time, counter setting value, discrimination voltage value, etc. in each of the above embodiments depending on the conditions of the toner sensor 17 and peripheral circuits.

〔Effect of the invention〕

As described in detail above, according to the present invention, a large number of discrete components are not used to determine the presence or absence of developer and whether the developer is installed or not, as is the case in the past. Trustworthiness improves.

Furthermore, the number of signal lines connected between the sensor and the control circuit can be reduced, which is advantageous in noise countermeasures and the like.

Furthermore, since only one CPU input port is required, the CPU input port can be used for other controls.
can be used effectively.

[Brief explanation of drawings]

FIG. 1(a) is a circuit diagram of the discrimination device of the first embodiment;
Figure (b) is a circuit diagram of the toner sensor, Figure 1 (C1 is C
A circuit diagram of a part of PtJ, Fig. 2 is a perspective view of a developing device to which the discrimination device of the first embodiment is applied, Fig. 3 is a schematic cross-sectional view of Fig. 2, and Fig. 4 is the output of the toner sensor. Diagrams showing signal waveforms: Figure 5 is a flowchart explaining the operation of the discrimination device of the first embodiment; Figure 6 is a flowchart explaining the operation of the discrimination device of the second embodiment; FIG. 8 is a block diagram of a developing unit to which a conventional developer remaining amount detecting device is applied; FIG. 9 is a circuit diagram of a conventional determining device. 17... Toner sensor, 21.27... Printer control circuit, 22.28... CPU. 25...FET. 26...Data bus, 28a...A/D converter, 29...Smoothing circuit, II...Power line, 12...Signal line, l...Grounding line.

Claims (2)

[Claims] (1) In an image forming apparatus that performs development using toner filled in a developer unit configured to be removably attached to the main unit, a pulse signal or a DC signal provided in the developer unit depending on the presence or absence of toner. a toner sensor that outputs a toner sensor, a control circuit provided in the main unit and provided with an input terminal for the toner sensor output signal, and an electrical connector, and a predetermined potential is applied to the toner sensor when the electrical connector is opened. a transmission circuit for transmitting an output signal to the input terminal, and the control circuit includes a determining means for determining whether the developing unit is attached to the main device and whether or not there is toner based on the signal input to the input terminal. A discrimination device comprising: (2) Claim 1, wherein the control circuit includes a microcomputer, and the input terminal of the control circuit is an interrupt terminal of the microcomputer.
Discrimination device described in section.