JPH0545962A - Copying device - Google Patents

Abstract

PURPOSE:To omit a switching mechanism for detecting the erroneous attachment of a component member for an electrophotographic process which is formed as a magazine and to maintain copying performance. CONSTITUTION:In the case that magazines 1-5 are not normally attached to a main body, rollers 2, 4a and 5 which are the loads of a high voltage generating power source 10 are not electrically connected, so that a load current does not flow to the rollers 2, 4a and 5 from the power source 10, and a PWM control circuit 11 makes the width (tw) of the switching pulse of a transistor 13 short so that the high voltage for the magazines 1-5 may be constant by a feedback current. The width (tw) of the switching pulse is integrated by integration circuits 20-22 through a diode 19, and integrated voltage is compared by a comparator 23 and a comparison signal is outputted to a control circuit 31. The control circuit 31 discriminates the comparison signal at the time of triggering and informs a user of the erroneous attachment of the respective magazines 1-5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine in which constituent members of an electrophotographic process are exchangeably formed into a magazine.

[0002]

2. Description of the Related Art Generally, in order to maintain copying performance, each component of the electrophotographic process in a copying machine requires a high degree of precision of parts and fine adjustments. Is going. However,
Since this maintenance work is very costly, in recent years, the components such as the developing device and the photoconductor of the electrophotographic process are made into magazines, and the user can replace each magazine at the end of its life. Many have been done. In this case, in order to maintain the copying performance in each magazine,
A mechanism and layout are required to prevent mounting mistakes.

Conventionally, in this type of copying apparatus, a detection mechanism such as a switch is provided on the copying apparatus main body side and the magazine side to form a closed circuit in order to detect whether or not the user has correctly mounted the magazine. Since a closed circuit is not formed in the case of a mounting error, the user is notified of that fact.

[0004]

However, in the above-mentioned conventional copying machine, it is necessary to provide a switch for detecting whether or not the user has correctly mounted the magazine on the copying machine main body side and the magazine side. However, there is a problem in that the mechanism and layout for maintaining the copying performance becomes complicated, and the copying performance cannot be maintained due to the warp.

In view of the above conventional problems, the present invention provides a copying apparatus capable of maintaining copying performance by omitting a switch mechanism for detecting a mounting error of a component member of a magazine-shaped electrophotographic process. With the goal.

[0006]

In order to achieve the above object, the first means is a copying machine in which constituent members of an electrophotographic process are exchangeably formed into a magazine, and the constituent members are used for the electrophotographic process. And a detecting means for detecting the presence or absence of the mounted state of the constituent member based on the output state of the applying means.

The second means is characterized in that the detecting means of the first means takes in a detection signal of the mounting state of the component through the conductor of the component.

In a third means, the applying means of the first or second means applies a high voltage for the electrophotographic process to the constituent members so as to be constant by pulse width modulation, and the detecting means applies a pulse of the applying means. It is characterized in that the presence or absence of the mounted state of the constituent member is detected by the width.

[0009]

In the first means, with the above-mentioned configuration, the presence or absence of the mounted state of the constituent members is detected by the output state of the high voltage for the electrophotographic process with respect to the constituent members which are formed into a replaceable magazine. Therefore, the copying performance can be maintained.

In the second means, since the detection signal of the mounting state of the constituent member is fetched through the conductor of the constituent member, it is possible to detect the presence or absence of the mounted state of the constituent member and to detect the contact state of the constituent member. Can be detected.

In the third means, the presence / absence of the mounted state of the constituent member is detected by the pulse width, so that it can be detected by a simple weak electric circuit.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a circuit diagram showing a high-voltage generating power source of an embodiment of a copying apparatus according to the present invention, FIG. 2 is a side view showing a roller mounting mechanism, and FIG. 3 is a schematic view of an electrophotographic process mechanism of the copying apparatus of FIG. FIG. 4 is an explanatory side view showing the electric current flow of the electrophotographic process mechanism in FIG.

In the high voltage generating power source 10 shown in FIG.
The PWM control circuit 11 receives from the control circuit 31 a trigger pulse for applying a high voltage to the charging roller 2, the developing roller 4a, and the transfer roller 5, which will be described later. With this trigger pulse, the PWM control circuit 11 generates a switching pulse having a width tw such that the period tf is constant and the applied voltage is constant, and this switching pulse is supplied to the base of the transistor 13 via the base resistor 12. Applied to. The collector of the transistor 13 is connected to one end of the transformer 14 on the primary side, and the emitter is grounded.

A voltage V is applied to the other end on the primary side of the transformer 14, and a high voltage on the secondary side is applied to the charging roller 2, the developing roller 4a and the transfer roller 5 via a diode 15. It The cathode of the diode 15 is also
It is grounded via the capacitor 16 and grounded via the voltage dividing resistors 17 and 18, and the monitor voltage of the applied voltage is fed back to the PWM control circuit 11 from the connection point of the voltage dividing resistors 17 and 18. The PWM circuit 11 controls the pulse width tw by the monitor voltage so that the high voltage applied to the charging roller 2, the developing roller 4a and the transfer roller 5 becomes a constant level.

The switching pulse of the PWM control circuit 11 is also applied to one end of the resistor 20 via the diode 19. The other end of the resistor 20 has a resistor 21 and a capacitor 22.
, And the other ends of the resistor 21 and the capacitor 22 are grounded. Therefore, the resistors 20 and 21 and the capacitor 22 form an integration circuit of the switching pulse of the PWM control circuit 11, and this integration voltage is calculated by the comparator 2
3 is compared with the threshold voltage, and the comparison signal is the comparison signal.
Is output to. Therefore, the diode 19, the integrating circuits 20 to 22 and the comparator 23 form a switching pulse detection circuit 30.

Next, the electrophotographic process mechanism of the copying machine in this embodiment will be described with reference to FIGS. The belt of the photoconductor belt unit 1 rotates in the clockwise direction, and along the rotation direction of the photoconductor belt unit 1, a charging roller 2 for precharging the surface of the photoconductor belt unit 1 before exposure and a ground. A roller 3 for developing, a developing unit 4 for developing the electrostatic latent image formed on the surface of the photosensitive belt unit 1 by exposure with toner, and a transfer roller 5 for transferring the toner image to a sheet are arranged. The charging roller 2, the developing roller 4a and the transfer roller 5 are made of a highly conductive material, and the developing unit 4 is integrally formed with the developing roller 4a together with the toner bottle.

These constituent members 1 to 5 are formed into a magazine and can be exchanged with respect to the main body of the copying machine. Further, the charging roller 2, the developing roller 4a and the shafts 2a of the transfer roller 5 are provided.
That is, as shown in detail in FIG. 2, the electrodes are attachable to and detachable from the receptacle 7 fixed to the side plate 6 of the copying apparatus main body. Each of the rollers 2, 4a, 5 is attached to the receptacle 7.
A spring 8 for supporting the
It is connected via a lead wire 9 to the high power source generating power source 10 shown in FIG. Therefore, when the high voltage from the high power source generating power source 10 shown in FIG. 1 is applied through the lead wire 9, the rollers 2, 4a, 5 become a load of the high power source generating power source 10, and as shown in FIG. Electric current is discharged from the rollers 2, 4a, 5 and flows into the photoconductor belt unit 1, and then flows through the grounding roller 3 to the ground side.

Next, the operation of the copying apparatus of this embodiment will be described. When the above magazines 1 to 5 are properly mounted on the main body and the copying operation is started, the PWM control circuit 11 triggers a switching pulse having a pulse width tw so that the high voltage to the magazines 1 to 5 becomes constant. And is applied to the transistor 13 via the base resistor 11. The transistor 13 is turned on and off by this switching pulse, and a high voltage flows to the secondary side of the transformer 14, and this high voltage is applied to the rollers 2, 4a and 5.
In this case, the applied current to each of the rollers 2, 4a, 5 flows to the photoconductor belt unit 1 as a discharge current and flows to the ground side via the grounding roller 3, so that the PWM control circuit 11
The switching pulse width tw is substantially constant.

On the other hand, when each of the magazines 1 to 5 is not properly mounted on the main body, the rollers 2, 4a and 5 which are the loads of the high power source generation power source 10 are not electrically connected, so that the high power source generation occurs. The load current stops flowing from the power source 10 to the rollers 2, 4a, 5 and the PWM control circuit 11 shortens the switching pulse width tw of the transistor 13 so that the high voltage to the magazines 1 to 5 becomes constant by the feedback current. To do. This switching pulse width t
w is integrated by the integrating circuits 20 to 22 via the diode 19, the integrated voltage is compared by the comparator 23, and the comparison signal is output to the control circuit 31. The control circuit 31
This comparison signal at the time of trigger is identified, and the user is notified of a mounting error of each magazine 1-5.

Therefore, according to the above embodiment, since the switching pulse width tw of the high voltage applied to the charging roller 2, the developing roller 4a and the transfer roller 5 is monitored,
As in the conventional example, the copy mechanism can be maintained by omitting the switch mechanism for detecting the mounting error of the component member of the electrophotographic process that is made into a magazine.

In the above embodiment, by monitoring only the switching pulse width tw, each magazine 1 to 5 is monitored.
However, as shown in FIG. 5, this detection signal is sent to the contact terminals 24 of each magazine 1-5.
It is possible to detect a mounting failure due to play at the time of mounting by being configured to monitor through.

[0022]

As described above, according to the first aspect of the present invention, in the copying apparatus in which the constituent members of the electrophotographic process are formed into replaceable magazines, a high voltage for the electrophotographic process is applied to the constituent members. Since there is provided an applying means for applying a voltage and a detecting means for detecting the presence or absence of the mounted state of the constituent member based on the output state of the applying means, the switch mechanism can be omitted and the copying performance can be maintained.

According to a second aspect of the present invention, the detection means according to the first aspect takes in the detection signal of the mounting state of the constituent member via the conductor of the constituent member, so that the presence or absence of the mounting state of the constituent member can be detected. In addition, the contact state of the constituent members can be detected.

In the third means, the applying means of the first and second means applies a high voltage for the electrophotographic process to the constituent members so as to be constant by pulse width modulation, and the detecting means applies the pulse of the applying means. Since the presence or absence of the mounted state of the constituent member is detected by the width, it can be detected by a simple weak electric circuit.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a high voltage generating power source of an embodiment of a copying apparatus according to the present invention.

FIG. 2 is a side view showing a roller mounting mechanism.

3 is a side view showing an outline of an electrophotographic process mechanism of the copying apparatus shown in FIG.

FIG. 4 is an explanatory diagram showing a current flow of the electrophotographic process mechanism in FIG.

5 is an explanatory diagram showing a modified example of the copying apparatus of FIG.

[Explanation of symbols] 1 photoconductor belt unit 2 charging roller 3 grounding roller 4 developing unit 4a developing roller 5 transfer roller 10 high power generation power supply 11 PWM control circuit 30 detection circuit 31 control circuit

Claims (3)

[Claims] 1. A copying apparatus in which constituent members of an electrophotographic process are exchangeably formed into a magazine, wherein an applying unit for applying a high voltage for the electrophotographic process to the constituent members and an output state of the applying unit are used. A copying machine, comprising: a detection unit that detects the presence or absence of the mounted state of the component. 2. The copying apparatus according to claim 1, wherein the detection unit takes in a detection signal of a mounting state of the constituent member via a conductor of the constituent member. 3. The applying means applies a high voltage for the electrophotographic process to the constituent member so as to be constant by pulse width modulation, and the detecting means applies a high voltage to the constituent member according to the pulse width of the applying means. The copying apparatus according to claim 1, wherein the presence or absence of the mounted state is detected.