JPH0642110B2 - Copier - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine, and more particularly, to improvement of a toner replenishing system in a copying machine having a cartridge type developing device.

“Prior art and its problems” In a copying machine using a two-component developer, the toner density changes depending on the copy amount. Therefore, the toner density is detected and the toner is replenished accordingly, and the toner density is set to a predetermined level. It is necessary to maintain.

In a conventional copying machine, a detector for detecting the toner concentration is provided in the developing device section, and the copying machine main body control section reads the output value of the detector and compares it with a predetermined reference value, and based on the comparison result. And outputs a toner replenishment signal to the toner replenishing means to control the toner replenishment amount.

The above predetermined reference value is different for each copying machine due to variations in the performance of the toner concentration detector, and therefore, is currently set individually for each copying machine.

By the way, in recent years, for convenience of maintenance and colorization of toner, a cartridge-type developing device has been proposed in which the developing device section is separated from the main body of the copying machine.

In a copying machine using such a cartridge type developing device, the combination of the copying machine body and the cartridge type developing device is not constant, and the cartridge type developing device may be replaced even if the copying machine body is the same.

Therefore, when the toner replenishment amount is controlled by the main body of the copying machine as in the conventional copying machine, the reference value most suitable for the cartridge developing device must be reset every time the cartridge developing device is replaced. However, there is a problem in that the effort and / or the configuration burden for the resetting is large.

[Object of the Invention] An object of the present invention is to automatically set a reference value most suitable for a developing device newly installed in a copying machine main body in a copying machine having a cartridge type developing device. To provide a copier.

[Constitution of the Invention] The copying machine of the present invention is a copying machine in which the developing device is easily detachable from the copying machine main body in a cartridge type. Of the toner concentration detector, the reference value setting means for storing the output value of the toner concentration detector as a reference value in the reference value memory according to the output of the attachment detector, and the output value of the toner concentration detector. And a reference value stored in the reference value memory, and a toner supply control circuit for outputting a toner supply signal based on a comparison is provided.

[Examples] Hereinafter, the present invention will be described in more detail based on the examples shown in the drawings. Here, FIG. 1 is an explanatory view of the structure of a copying machine according to an embodiment of the present invention, FIG. 2 is a sectional view of the essential parts showing the mechanical portion of the developing device of the copying machine shown in FIG. 1, and FIG. FIG. 4 is a circuit diagram of a configuration of another embodiment, and FIG. 4 is a circuit diagram of an additional circuit to the embodiment shown in FIG. The present invention is not limited to this embodiment.

In the copying machine 1 shown in FIG. 1, the developing device 10 is of a cartridge type and can be easily attached to and detached from the copying machine main body 20. The electrical connection between the two is performed by the developing device 10.
The first connector 32 provided on the copying machine and the second connector 33 provided on the copying machine body 20 are joined together.

The developing device 10 includes a magnetic brush unit 11, a toner replenishing unit 12, a toner concentration detector 13, and a short-circuit wire 14 that short-circuits the two contacts 32 a and 32 b of the first connector 32.

The magnetic brush means 11 has the same structure as a conventionally known one,
For example, the structure shown in FIG. The stirring blade 15 rotates to push the mixture of toner and carrier to the position of the sleeve 16, and the sleeve 16 rotates to bring the mixture adsorbed on the surface into sliding contact with the surface of the photosensitive drum D. The magnet roll 17 adsorbs the mixture on the surface of the sleeve 16.

The toner replenishing means 12 has a configuration similar to that of a conventionally known device, for example, the configuration shown in FIG. When the replenishment roll 18 is rotated, the toner in the hopper 19 is supplied to the magnetic brush means 11. The rotation of the replenishment roll 18 is controlled by a toner replenishment signal from the copying machine main body 20. As another example of the toner replenishing means, there is one that adjusts the toner replenishment amount by opening and closing an electromagnetic shutter.

The copying machine main body 20 includes an AD converter 21, a reference value memory 22, a microprocessor 23, a power supply circuit 24 for these control circuits, a relay 25, and a main switch 26.

The AD converter 21 converts the output signal of the toner concentration detector 13 into a digital value and outputs it to the microprocessor 23.

The reference value memory 22 is a so-called non-volatile read / write memory, and holds the reference value even when the main switch 26 of the copying machine body 20 is turned off.

The microprocessor 23 is the center of the toner supply control, and its operation will be described in detail below.

First, consider an operation of turning on the main switch 26 with the developing device 10 pulled out from the copying machine main body 20, and then mounting the developing device 10.

When the main switch 26 is turned on, electric power is supplied from the power supply 24, so that the AD converter 21, the reference value memory 22, and the microprocessor 23 start operating.

The microprocessor 23 turns off the relay 25 immediately after the power is turned on. Therefore, even if the developing device 10 is pulled out and the power is turned on, the power line is not exposed from the connector 33 and the safety is ensured.

Then microprocessor 23, waiting for the pattern signals from the contact 33 _b to send a signal of a predetermined pattern and the contact 33 _a of the connector 33 is returned.

However, if the developing device 10 is not attached, the pattern signal is not input, so the microprocessor 23 recognizes that the developing device 10 is not attached. Therefore, in this case, the relay 25 is turned off and stands by.

When the developing device 10 is mounted in this state, the developing device 10
The contacts 32 _a and 32 _b of the connector 32 of FIG.
Will make a U-turn of the pattern signal transmitted by itself and receive it again. Therefore, it is recognized that the developing device 10 that has been pulled out is attached.

Then, the microprocessor 23 turns on the relay 25. Thereby, the magnetic brush means 1 of the developing device 10
1 works. However, since the toner replenishment signal is not output, the toner replenishing means 12 does not operate yet.

After a lapse of a predetermined time, for example, 30 seconds, after turning on the relay 25, the microprocessor 23 causes the toner concentration detector 13 to
The output value of is read through the AD converter 21. Further, the read output value is stored in the reference value memory 22 as a reference value.

Since such an operation is performed, if the toner and the carrier having the reference density are put in the magnetic brush means 11 at this time, the correct reference density is used as the reference value in the reference value memory 22.
Is set to.

After setting the reference value, the microprocessor 23 reads the output value of the toner concentration detector 13, compares this with the reference value stored in the reference value memory 22, and if the toner concentration decreases, Outputs a toner replenishment signal.

In this comparison, the supply level value and the stop level value are calculated above and below the stored reference value,
The toner replenishment signal may be output when the value falls below the replenishment level value, and the toner replenishment signal may be stopped when the stop level is reached.

When the toner replenishment signal is output, the toner replenishing means 12 rotates the replenishing roll 18 to remove the toner by the magnetic brush means 11.
Supply to. Thus, the toner density is maintained at a predetermined level.

Now, let us consider a case where the main switch 26 is turned on from the OFF state while the developing device 10 is still attached to the copying machine main body 20.

As in the above, the microprocessor 23 turns off the relay 25 immediately after power-on and does not output the toner replenishment signal. The same is true of waiting from the contact 33 _a sends a predetermined pattern signal in the contact 33 _b of the pattern signal is returned.

However, since the developing device 10 is already mounted, the pattern signal is received at the same time as the transmission immediately after power-on. Therefore, the microprocessor 23 uses the developing device 1
Recognize that 0 was already installed.

When recognizing that the developing device 10 is already attached when the main switch 26 is turned on, the microprocessor 23 does not set the reference value and maintains the reference value stored in the past as it is. Thus, even if the main switch 26 is turned on / off while the developing device 10 is still mounted, the reference value initially set is maintained.

After all, in the copying machine 1, if the developing device 10 is mounted with the developing device 10 loaded with toner and carrier of the reference density and the main switch 26 of the copying machine main body 20 is turned on, the reference value memory 22 A new reference value is set in the, and the reference value is maintained thereafter.

On the other hand, when the user attaches or detaches the developing device 10,
Normally, the main switch 26 is turned off. At this time, since the microprocessor 23 does not recognize the attachment / detachment of the developing device 10, the reference value is not reset.
The reference value set at the beginning is not destroyed.

FIG. 3 shows another embodiment of the present invention.

In this copying machine 1 ', the structure of the developing device 10 is the same as that of the developing device 10 of the above-mentioned embodiment, and the same reference numerals are given to the components. Further, in the constitution of the copying machine main body 20 ', the AD converter 21, the control power supply 24, and the main switch 26 are the same as those in the copying machine main body 20 of the above-mentioned embodiment, and the same reference numerals are given.

It should be noted that the reference value memory 22 and the microprocessor 23 are replaced by a reference value memory 22 ', a differentiating circuit 27, a delay circuit 28 and a comparison control circuit 29.

When the developing device 10 in which the toner of the reference density and the carrier are inserted is attached with the main switch 26 of the copying machine body 20 'turned on, the magnetic brush means 1 is attached at the same time.
1 is energized to operate, and becomes a steady state after a predetermined time.

On the other hand, at the same time when the developing device 10 is attached, the differentiating circuit 27
Outputs a differential pulse, which is input to the delay circuit 28, so that the delay circuit 28 outputs a storage command pulse after a predetermined time, whereby the reference value memory 22 'stores the output value of the AD converter 21 at that time. Remember. In other words,
By mounting the developing device 10, the output values of the toner density detector 13 for the toner of the reference density and the carrier are set in the reference value memory 22 'as the reference values.

The comparison control circuit 29 compares the output value of the toner density detector 13 read via the AD converter 21 with the stored reference value, and outputs a toner replenishment signal based on the comparison result.

As described above, the short-circuit line 14 and the differentiating circuit 27 form the mounting detecting means, the delay circuit forms the reference value setting means, and the comparison control circuit 29 forms the toner replenishment control circuit.

In this copying machine 1 ', the reference value is reset each time the power is turned off and on with the developing device 10 still attached. However, if the correct reference value is set first, the toner is replenished thereafter. Since the toner density is maintained by the control, it is considered that there is no particular problem in practical use. However, as shown in FIG. 4, if the AND gate 36 and the charging circuit 35 are added and the output signal of the differentiating circuit 27 is cut off for a certain time after the power is turned on, the power is turned off and on. It is possible to prevent resetting the reference value every time.

On the other hand, since the differentiation circuit 27 does not output the differentiation pulse even if the developing device 10 is pulled out and the power is turned on / off,
The stored reference value is maintained without resetting the reference value.

[Advantages of the Invention] According to the present invention, in a copying machine in which the developing device can be easily detached from the copying machine main body in a cartridge type, the toner concentration detector, the reference memory, and the developing device are mounted in the copying machine main body. And a reference value setting means for storing the output value of the toner concentration detector as a reference value in the reference value memory according to the output of the attachment detection means, and the output value of the toner concentration detector. A copier having a toner replenishment control circuit that outputs a toner replenishment signal based on a comparison with a reference value stored in the reference value memory is provided. Just put the toner and carrier of the above into the main body of the copier, and the proper toner density is automatically set as the reference value in the reference value memory. The toner replenishment control is preferably performed based on the reference value of.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a structural explanatory view of a copying machine according to an embodiment of the present invention, and FIG.
FIG. 1 is a sectional view of the essential parts showing the mechanical portion of the developing device of the copying machine shown in FIG. 1, and FIG.
FIG. 4 is a circuit diagram of an additional circuit to the embodiment shown in FIG. (Explanation of symbols) 1,1 '... Copier 10 ... Developing device 13 ... Toner concentration detector 14 ... Short-circuit line 20,20' ... Copier body 22,22 '... Reference value memory 23 ... ... Microprocessor 27 ... Differentiating circuit, 28 ... Delay circuit 29 ... Comparison control circuit. 32 ... 1st connector 32a, 32b ... Contact 33 ... 2nd connector 33a, 33b ... Contact.

Claims (2)

[Claims] 1. In a copying machine in which a developing device is easily removable from the copying machine main body in a cartridge type, a mounting detection for detecting that a toner density detector, a reference memory, and a developing device are mounted in the copying machine main body. Means, reference value setting means for storing the output value of the toner concentration detector as a reference value in the reference value memory in accordance with the output of the mounting detection means, and the output value of the toner concentration detector and the reference value memory A copying machine comprising a toner replenishment control circuit that outputs a toner replenishment signal based on a comparison with the reference value. 2. A mounting detecting means for short-circuiting a short-circuit line between two contacts of a connector on one side of each connector for connecting a copying machine main body and a developing device, and the other corresponding to the two contacts. A short circuit detection circuit for detecting a short circuit between two contacts of the side connector, and a mounting detection output circuit for outputting a mounting detection signal when the short circuit detection circuit changes from a state in which no short circuit is detected to a state in which a short circuit is detected. The copying machine according to claim 1, which is provided.