JP3132073B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having a structure for judging whether a mounted drum unit is new or old.

[0002]

2. Description of the Related Art Generally, in an image forming apparatus using an electrophotographic system, a photosensitive drum is unitized, and when the life of the photosensitive drum expires, the entire unit is replaced. When the old unit is replaced with a new unit, it is necessary to clear the drum counter for measuring the life of the photosensitive drum, so that the image forming apparatus itself determines whether the drum unit is new or old.

In this type of conventional image forming apparatus,
A detection object that moves with the rotation of the drum is provided on the unit side, and a sensor that detects the detection object is provided at a position on the apparatus body side where the detection object finally moves; If the unit attached to the main unit is a new unit, the sensor does not respond when it is attached, and when it is attached, the photosensitive drum rotates a predetermined number of times and the detected object moves to a predetermined position. Since the sensor reacts for the first time, it is possible to confirm that the mounted unit is a new unit.

[0004]

However, in the above-described conventional image forming apparatus, a driving mechanism for moving the object to be detected with the rotation of the drum must be provided.
Since it is necessary to provide a sensor for detecting the object to be detected on the apparatus main body side, there is a drawback that the structure becomes complicated and the cost increases.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an image forming apparatus having a simple structure and capable of discriminating a new or old drum unit at low cost.

[0006]

In order to solve the above-mentioned problems, in the image forming apparatus according to the present invention, a fuse whose one terminal is grounded on the drum unit side is provided on the drum unit while the drum unit is mounted on the apparatus main body. A pair of terminals that are connected to both ends of the fuse when mounted, and are connected to a predetermined voltage on the device body side, respectively. The apparatus main body is provided with a unit for determining whether or not the unit is new and old, and a new and old discriminating means, and a fuse blowing means for supplying an overcurrent to the fuse and blowing the fuse when the mounted drum unit is determined to be new. And

[0007]

In the above construction, the drum unit is simply provided with an inexpensive fuse such that one terminal is grounded on the drum unit side, and the apparatus main body is provided when the drum unit is mounted on the apparatus main body. A pair of terminals connected to both ends of the fuse and connected to a predetermined voltage on the apparatus main body side, and a unit that determines whether or not the drum unit is mounted and whether the mounted drum unit is new or old based on the voltage of the pair of terminals. Both the presence / absence new / old discriminating means and the fuse blowing means for supplying overcurrent to fuses are provided with relatively simple circuits. Can be.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a circuit diagram showing a structural portion and the like for determining whether a drum unit is new or old in an image forming apparatus.

A fuse 3 is provided in the drum unit 2. When the drum unit 2 is mounted on the main body of the image forming apparatus, one end 3a of the fuse 3 is connected to a terminal 4a on the main body side and the other end 3b of the fuse 3 is connected. Are connected to the terminals 4b on the apparatus main body side, respectively. Also,
The other end 3b of the fuse 3 is connected to a drum shaft (not shown) and is grounded through the drum shaft.

The CPU 1 controls the whole of the image forming apparatus and controls the replacement of the drum unit based on the life of the drum. The fuse blow control terminal 1a of the CPU 1 is connected to the base of a transistor T via a resistor R1, and the emitter of the transistor T has a V of 24V.
cc1, and the collector of the transistor T is connected to the terminal 4a.

The unit new / old confirmation terminal 1b of the CPU 1 is
It is connected to Vcc2 of 5V via a resistor R2. The diode D is disposed between the collector of the transistor T and the unit new / old confirmation terminal 1b. The diode D forms an electrical conduction state between the unit new / old confirmation terminal 1b and the terminal 4a. Is prevented from flowing into the unit new / old confirmation terminal 1b.

The unit presence / absence confirmation terminal 1c of the CPU 1
It is connected to Vcc2 via a resistor R3 and to the terminal 4b. The body cover closing confirmation terminal 1d of the CPU 1 is connected to a sensor (not shown) that detects the open / closed state of the body cover (not shown). In the above configuration, when the drum unit 2 is not mounted on the apparatus main body, a 5 V voltage of Vcc2 is applied to the unit new / old confirmation terminal 1b and the unit presence / absence confirmation terminal 1c, so that both terminals are in the "H" state. . When a new unit (the fuse 3 is not blown) is mounted on the apparatus main body as the drum unit 2, Vcc2
5V voltage flows from the terminal 4a to the ground through the fuse 3 and the drum shaft, and the terminal 4b
Then, both terminals of the unit new / old confirmation terminal 1b and the unit presence / absence confirmation terminal 1c are in the "L" state. On the other hand, when the old unit (the fuse 3 is blown out) is attached to the apparatus main body as the drum unit 2, the unit new / old confirmation terminal 1b becomes "H" and the unit presence / absence confirmation terminal 1c becomes "L" state. Become.

When the fuse cut control terminal 1a is in the "H" state, the transistor T does not turn on, so that no overcurrent is supplied to the fuse 3 by the voltage of 24 Vcc1 and the fuse 3 is not blown. On the other hand, when the fuse blowing control terminal 1a is in the "L" state, the transistor T is turned on, so that an overcurrent of 24 V of Vcc1 is supplied to the fuse 3, and the fuse 3 is blown.

FIG. 2 is a flowchart showing the control contents of the CPU 1 performed when the drum unit is replaced based on the life. First, it is determined by the drum counter whether or not the drum life has expired (S1). When it is determined that the drum life has expired (for example, when the drum counter has counted 10,000), the printing operation is stopped (S2). A drum replacement request display is performed (S3). Then, the flag F is set to 0 (S4).

Next, it is determined whether or not F = 0 (S5).
If F = 0, the presence or absence of a unit is determined by the unit presence / absence confirmation terminal 1c (S6). If there is no unit in this determination, it indicates that the old unit has been removed from the apparatus main body, so that F = 1 is set (S7), and the presence or absence of the drum is determined again (S8). If it is determined in step 8 that there is a unit, it indicates that the drum unit is mounted on the apparatus main body again, and it is determined whether or not the mounted unit is a new unit (S9).

If the installed unit is an old unit, a buzzer for notifying that the installed unit is an old unit is sounded (S10), and the process proceeds to step 4.
The operations of steps 5 to 8 are repeated again. On the other hand, if the installed unit is a new unit, the replacement request display is stopped (S11), and it is determined whether or not the main body cover is closed (S12). If the unit cover is closed, the drum counter is cleared. (S13), the fuse blow control terminal 1a is set to "L".
In this state, the fuse 3 is blown (S14), and the process returns.

As described above, the drum unit 2 is provided only with the inexpensive fuse 3, and the apparatus main body is provided with a means for detecting whether or not a current flows through the fuse 3, and a means for supplying an overcurrent to the fuse 3. In any of the above, since only a circuit composed of a relatively simple circuit is provided, it is possible to identify the old and new of the drum unit 2 with an inexpensive and simple structure.

[0018]

As described above, according to the present invention, there is an effect that the presence or absence of a drum unit and the old and new can be distinguished with a simple and inexpensive structure.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a structural portion and the like for determining whether a drum unit is new or old in an image forming apparatus as one embodiment of the present invention.

FIG. 2 is a diagram showing a C performed when a drum unit is replaced based on a service life.
5 is a flowchart showing control contents of a PU.

[Explanation of symbols]

 1 CPU 1a Fuse blow control terminal 1b Unit new / old confirmation terminal 1c Unit presence / absence confirmation terminal 2 Drum unit 3 Fuse

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 15/00 550 G03G 21/00 350-352 G03G 21/00 370 G03G 21/00 510 G03G 21/16-21/18

Claims (1)

(57) [Claims] 1. One of the terminals is grounded on the drum unit side.
While providing the fuses in the drum unit, said Dora
With Muyunitto are connected to both ends of the fuse when it is attached to the main body, it the device body
A pair of terminals connected to a predetermined voltage,
Unit presence / absence discrimination means for judging the presence / absence of a drum unit and whether or not the drum unit is mounted based on the terminal voltage <br/> New / old identification means, and supplying an overcurrent to the fuse when the mounted drum unit is determined to be new And a fuse blowing means for blowing the fuse.