JP2000035733A - Electrophotographic image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discriminate, at a low cost without many special components but with a smaller number of components, whether components of an image forming unit is new or not, when the unit is attached to an image forming device main body. SOLUTION: At the start and end of a reset operation, which is performed when the cover of the image forming device main body is closed for example, the image forming device causes a current to flow between a developing roller 21 and a conductive member, such as a conductive thin-layer blade 23 or a conductive Mylar, which elastically contacts it. In the case the newly-attached image-forming unit is a fresh one, toner 45 sticks to the periphery of the developing roller 21 due to the reset operation and the value of resistance becomes high and, therefor, based on a difference between the value of the current flowing at the start of the reset operation and that at the end of it, the device judges whether the attached image-forming unit is a fresh one or not.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention can be applied to an image forming apparatus such as a copying machine, a printer, a facsimile, and a multifunction peripheral thereof. More specifically, among them, in particular, a latent image is formed by performing charging and writing on an image carrier, toner is applied to develop the latent image, and the image obtained by the development is transferred to a paper or card. The present invention relates to an electrophotographic image forming apparatus that performs recording on a recording medium.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic image forming apparatus of this type includes an image carrier and a part or all of a charging unit, a writing unit, a developing unit, a transfer unit, a cleaning unit, etc. provided around the image carrier. Are housed in a single housing to form an integrated image forming unit, and the image forming unit is detachably provided in the image forming apparatus main body. As a result, maintainability and the like have been improved.

However, in such an image forming unit, each part gradually deteriorates with use, and the image quality deteriorates over time. Therefore, it is necessary to replace the image forming unit with a new image forming unit before the image quality is significantly reduced.

For this reason, the image forming unit has conventionally been replaced with a new one by knowing the replacement time from count values such as the number of recordings on the recording medium, the number of rotations of the image carrier and the driving time. At the time of this replacement, the count value is cleared and a new count is started.

However, when replacing the image forming unit,
Since a used image forming unit may be attached by mistake, many conventional image forming apparatuses first determine whether the attached image forming unit is new, and then clear the count value. A new count was started.

[0006]

However, such a conventional electrophotographic image forming apparatus requires a large number of dedicated parts in order to determine whether or not the image forming unit is new. There was a problem that the score increased and the cost increased.

Therefore, an object of the present invention is to determine whether or not an image forming unit is new when the image forming unit is attached to the main body of the image forming apparatus, without requiring many dedicated parts, and without much. An object of the present invention is to enable inexpensive discrimination based on the number of parts.

[0008]

Therefore, according to the present invention, there is provided an electrophotographic image forming apparatus including at least a developing unit as in an embodiment described with reference to the following drawings. An image forming unit 36 configured and detachably provided to the image forming apparatus main body 10
A developing roller 21 that is provided in the developing unit 14 of the image forming unit 36 and adheres the toner 45 to develop the latent image on the image carrier 12, and makes elastic contact with the developing roller 21.
A current flows between the conductive member, such as the conductive thin layer blade 23 and the conductive mylar 47, and between the developing roller 21 and the conductive member at the beginning and end of the reset operation. Control means for determining whether or not the unit 36 is new.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, as in an embodiment described with reference to the following drawings, for example, the conductive member is a conductive thin layer blade. It is characterized by the following.

According to a third aspect of the present invention, there is provided the image forming apparatus according to the first aspect, for example, as shown in FIGS.
As described in the embodiment described with reference to FIG. 1, the developing roller 21 and one of the conductive members are grounded.

In the present invention, a current flows between the developing roller 21 and the conductive member at the beginning and end of a reset operation performed when the cover of the image forming apparatus main body 10 is closed, for example. It is determined whether or not the image forming unit 36 is new from the difference in the values.
When it is determined that the image forming unit 36 is new, for example, the stop of image formation of the image forming apparatus main body 10 is released.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a main part of an electrophotographic image forming apparatus using a one-component developing system according to the present invention. The illustrated image forming apparatus includes a drum-shaped image carrier 12 substantially at the center of an apparatus main body 10 showing only a main part.

Around the image carrier 12, a charging unit 13, a writing unit (not shown), a developing unit 14, a transfer unit 15, a fixing unit (not shown), a cleaning unit 16 and the like are arranged in the rotation direction indicated by the arrow. Provide.

The developing section 14 includes an intermediate roller 20, a developing roller 21, a toner stirring member 22, a thin layer blade 23 and the like in a developing chamber 18.
Is replaceably attached. Toner cartridge 25
The toner agitating member 26 is also provided therein. This developing unit 14
The developing is performed by a one-component developing method, and toner is stored in a developing chamber 18.

The recording medium is sequentially fed out from a paper feeding unit (not shown) and conveyed. The recording medium is abutted between registration rollers 28 through a conveyance path 27 and stopped. The registration rollers 28 are synchronized with the rotation of the image carrier 12. Is rotated and fed between the image carrier 12 and the transfer unit 15.

On the other hand, the image carrier 12 is rotated in the counterclockwise direction and the surface of the image carrier 12 is uniformly charged by the charging section 13 with the rotation. Irradiate to form a latent image on the image carrier 12.

The developing unit 14 replenishes the toner in the toner cartridge 25 into the developing chamber 18 while rotating and agitating the toner agitating member 26 with the driving force transmitted from the apparatus main body 10 side. The toner is sent to the developing roller 21 while being stirred by the toner stirring member 22.

The toner adhering to the developing roller 21 is thinned by the thin blade 23 and charged, and then adheres to the image carrier 12 via the intermediate roller 20, and the image carrier 1
2. The latent image on 2 is developed into a visible image.

As the image carrier 12 rotates, the image formed on the image carrier 12 as described above is transferred onto the recording medium fed between the image carrier 12 and the transfer section 15 as described above. The transfer is performed by the transfer unit 15.

After the charge is removed by the charge removing lamp 30,
After the transferred image is fixed by a fixing unit (not shown), the image is discharged to a paper discharge unit (not shown) provided on the apparatus main body 10, for example, and the recorded recording medium is stacked on the paper discharge unit.

On the other hand, with the rotation of the image carrier 12 after the image transfer, the residual toner on the surface is removed by the cleaning blade 31 of the cleaning unit 16, and the removed toner is collected in the collection chamber 33 by the collection roller 32. I do.

Incidentally, in such an image forming apparatus,
Since the recording medium being conveyed may be caught, it is sometimes necessary to open the cover of the apparatus main body 10 so that the jammed paper can be taken out. Open the cover of the device body 10,
It is also necessary to periodically clean the inside of the apparatus body 10. Also,
Since each part deteriorates with use, it is necessary to open the cover of the apparatus main body 10 and repair or replace each part at an appropriate time.

Therefore, in consideration of such convenience at the time of maintenance, in the image forming apparatus of the illustrated example, the image carrier 12 and the developing unit 14 are housed in one housing 35 to form an integrated image forming unit 36. The charging unit 13 and the cleaning unit 16 are housed in another case 37 to form another image forming unit 38.

The image forming units 36 and
38 are individually and detachably provided in the image forming apparatus main body 10. Reference numeral 39 in the figure denotes a sensor for detecting the attachment of one image forming unit 36.

Further, in such an image forming apparatus, since the toner is consumed with use, a toner end sensor 40 is provided on the apparatus main body 10 to detect the remaining amount of toner in the toner cartridge 25. The toner end sensor 40
Using a magnetic sensor, a piezoelectric sensor, or the like, the presence / absence of toner is determined based on two values, “present” and “absent”. In this example, a magnetic sensor is used as the toner end sensor 40.

When the toner end sensor 40 determines that there is no toner, a warning is issued to urge the user to replace the toner cartridge 25, or the warning is locked so that the apparatus main body 10 cannot be used. Then, the user opens the cover of the apparatus main body 10, takes out the image forming unit 36, replaces the toner cartridge 25, and closes the cover.

Now, in such an image forming apparatus, each part is deteriorated with use and the image quality deteriorates. Therefore, it is necessary to replace the image forming units 36 and 38 before the image quality remarkably deteriorates with time. is there.

Therefore, the life of the image forming unit 36 is determined based on count values such as the number of recordings on the recording medium, the number of rotations and the driving time of the image carrier 12, the ON time of the fixing unit, and the number of replacements of the toner cartridge 25. It is determined whether or not the battery life has expired, and if it is determined that the battery has reached the end of its life, a warning is issued to prompt the user to replace the battery. The user opens the cover of the apparatus main body 10 based on the warning and replaces the image forming unit 36 with a new one.

However, when the image forming unit 36 is replaced, a used unit may be mistakenly attached. Therefore, in the first embodiment according to the present invention, the above-mentioned thin layer blade 23 is made of a conductive material, and is connected to a power supply 43 via an ammeter 42 as shown in FIG. Then, when the image forming unit 36 is replaced, control is performed, for example, as shown in FIG.

That is, when the cover of the apparatus main body 10 is opened, the image forming unit 36 is replaced and then closed (step S1), a current flows from the thin layer blade 23 to the developing roller 21 to perform the first current detection. Is performed, and the current value at this time is measured by the ammeter 42 (step S2).

When the cover of the apparatus main body 10 is closed, the reset operation is performed together with the first sensor detection, and the developing unit 14 is driven to apply the toner 45 to the peripheral surface of the developing roller 21 as shown in FIG. Attach (Step S3). Therefore, assuming that the newly attached image forming unit 36 is a new one, the state of the toner “absent” is changed to the state of the toner “present”.

Then, as shown in FIG. 3, a current is again supplied from the thin layer blade 23 to the developing roller 21 to perform a second current detection, and the current value at this time is measured by the ammeter 42 (step). S4). At this time, when the toner is in the “present” state, the resistance value increases and the current hardly flows.

FIG. 5 shows the developing roller 21 and the thin layer blade 2.
A bias voltage (750 V) application time (seconds) between
6 is a graph showing a relationship between a current value (μA) flowing between the developing roller 21 and the thin layer blade 23 at that time. As can be seen from FIG. 5, when the detection time is set to 4 to 8 seconds, since the resistance value is lower in the case of "no toner" than in the case of "toner", a current larger by at least 0.5 .mu.A flows. Become.

It is determined whether the value obtained by subtracting the current value in the second current detection from the current value in the first current detection is 0.5 μA or more (step S5). Sets the image forming unit 36 to be new (step S6), resets the count value used to determine the life of the image forming unit 36 (step S7), and proceeds to the image forming operation.

However, when it is not 0.5 μA or more,
The image forming unit 36 is not new (step S
8) After a warning is displayed to that effect (step S
9), shift to an image forming operation.

In the above-described first embodiment of the present invention, a current flows from the thin layer blade 23 to the developing roller 21. However, in the second embodiment, as shown in FIGS. 6 and 7, a current is caused to flow from the developing roller 21 to the thin layer blade 23. Then, when the newly attached image forming unit 36 is a new one, the first current detection is performed in the state of “no toner” shown in FIG. 6, and the first current detection is performed in the state of “present” of the toner 45 shown in FIG. 2
Perform current detection twice.

In the above-described two embodiments, the thin layer blade 23 elastically contacting the developing roller 21 is made of a conductive material, and the developing roller 21 and the thin layer blade 2 are made of a conductive material.
A current is passed between the three. However, in the third embodiment, as shown in FIG. 8, the thin layer blade 23 is made of a non-conductive material such as resin or rubber, and a conductive mylar 47 that elastically contacts the developing roller 21 is separately provided. Is a conductive member.

Then, a current is supplied from the developing roller 21 to the conductive member, and the image is determined based on the difference in the current flowing between the first current detection and the second current detection in the same manner as in the first embodiment. It is determined whether or not the forming unit 36 is new.

In the fourth embodiment, as shown in FIG. 9, the thin layer blade 23 is made of a non-conductive material, and the conductive mylar 47 which makes elastic contact with the developing roller 21 for the purpose of preventing toner scattering or the like is made conductive. Material. Then, a current flows from the developing roller 21 to the conductive member, and similarly, it is determined whether or not the image forming unit 36 is new, based on a difference in current flowing between the first current detection and the second current detection. .

In general, in an electrophotographic image forming apparatus, when the cover of the apparatus main body 10 is opened for maintenance or the like, for example, to prevent an abnormal image and for safety, the apparatus is turned off and the driving of the apparatus main body 10 is stopped. Reset switch.

When the cover is subsequently closed, the reset switch is turned on to start driving the apparatus main body 10. First, a reset is performed to check the presence or absence of a recording medium, the temperature of the fixing unit, the charge amount of the toner 45, and the like. Perform the operation. This is also called an initial operation, an inching operation, a return operation, and the like.

According to the present invention, a current flows between the developing roller 21 and conductive members such as the conductive thin layer blade 23 and the conductive mylar 47 at the beginning and end of such a reset operation. Is to determine whether the image forming unit 36 is new.

In the above-described embodiment, it is determined whether or not the newly installed image forming unit 36 is new, and if not, a warning is displayed only when the image forming unit 36 is new, and all the operations are shifted to the image forming operation. .

However, when the image forming unit 36 reaches the end of its life, the apparatus main body 10 is locked to stop the image formation.
When the cover is opened and then closed, it is determined whether or not the newly attached image forming unit 36 is new, and the stop of the image formation is released only when it is determined that the image forming unit 36 is new,
The operation may shift to the image forming operation.

In the above-described embodiment, the image forming unit 36 according to the present invention comprises the image carrier 12 and the developing unit 14. However, the image forming unit
The image carrier 1 includes at least the developing unit 14.
2 or another charging unit 13 together with the image carrier 12.
Needless to say, the cleaning unit 16 and the cleaning unit 16 may be included.

[0046]

Therefore, according to the first to third aspects of the present invention, when the image forming unit is attached to the image forming apparatus main body with almost no new parts added, the image forming unit is new. Can be determined inexpensively with a small number of parts.

According to the second aspect of the present invention, since the conductive member is a thin layer blade, it is possible to determine whether or not the image forming unit is new using all existing components, Discrimination can be made inexpensively with a smaller number of parts.

According to the third aspect of the present invention,
Since either the developing roller or the conductive member is grounded, it is possible to determine the cost with a smaller number of components.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part of an electrophotographic image forming apparatus according to the present invention.

FIG. 2 is an explanatory schematic configuration diagram of a developing roller portion according to the first embodiment of the present invention.

FIG. 3 is a flowchart when the image forming unit is replaced in the first embodiment.

FIG. 4 is a schematic configuration diagram illustrating a state in which toner adheres to an image carrier during a reset operation in the first embodiment.

FIG. 5 is a graph showing a relationship between a bias voltage application time between the developing roller and the thin layer blade and a current value flowing between the developing roller and the thin layer blade at that time.

FIG. 6 is an explanatory schematic configuration diagram of a developing roller portion showing a second embodiment according to the present invention.

FIG. 7 is an explanatory schematic configuration diagram showing a state in which toner adheres to an image carrier during a reset operation in the second embodiment.

FIG. 8 is a schematic configuration diagram of a developing roller showing a state in which toner adheres to an image carrier during a reset operation according to a third embodiment of the present invention;

FIG. 9 is a schematic diagram illustrating the configuration of a developing roller according to a fourth embodiment of the present invention, showing a state in which toner adheres to an image carrier during a reset operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Image forming apparatus main body 12 Image carrier 13 Charging part 14 Developing part 15 Transfer part 16 Cleaning part 21 Developing roller 23 Thin layer blade (conductive member) 36 Image forming unit 42 Ammeter 43 Power supply 45 Toner 47 Conductive mylar (Conductive) Material)

Continued on front page F-term (reference) 2H027 DA01 DA27 DA41 DD02 DE03 DE04 EC09 EC10 ED08 EE02 EH03 EK03 GA30 GB03 GB09 GB19 HA08 HA12 HB13 HB15 HB18 2H071 BA04 BA13 DA06 DA08 DA09 DA13 DA15 DA32 DA34 2H077 AA12 AD06 DA13 AD17 DA17 DA52 DA57 DA74 DA75 DB10 DB14 DB21 EA11 FA25 GA04

Claims (3)

[Claims] An image forming unit that includes at least a developing unit and is detachably attached to an image forming apparatus main body; and an image forming unit that is provided in a developing unit of the image forming unit. A developing roller for developing the latent image; a conductive member elastically in contact with the developing roller; and a current flowing between the developing roller and the conductive member at the beginning and end of the reset operation. An electrophotographic image forming apparatus comprising: a control unit that determines whether a forming unit is new. 2. The electrophotographic image forming apparatus according to claim 1, wherein said conductive member is a conductive thin layer blade. 3. The electrophotographic image forming apparatus according to claim 1, wherein one of the developing roller and the conductive member is grounded.