JP2002372840A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device that restricts occurrence of a standing wave caused by vibration and uniformly cleans developer passage holes 17. SOLUTION: In FPC 17, a vibration transmission means 63 is disposed in parallel to a developer passage hole line 17g. A vibration generation means 61 is disposed on the vibration transmission means 63. The vibration generated by the vibration generation means 61 is made into irregular vibration in which a frequency component is unspecified.

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 such as a copying machine, a facsimile, a printer and the like, and more particularly to an image forming apparatus which forms an image on a recording medium by causing a powdery developer to fly by the action of an electric field. It belongs to the technical field of the image forming apparatus described above.

[0002]

2. Description of the Related Art Conventionally, there is known an image forming apparatus which forms an image on a recording medium by causing a powdery developer to fly by the action of an electric field. This image forming apparatus includes, for example, a head 1 in which a toner 7 as a developer is stored, as shown in FIG.
And an intermediate image holding belt 2 disposed opposite to the head 1. In addition, although not shown, a transfer for transferring an image formed on the intermediate image holding belt 2 to recording paper And fixing means for fixing the image on the recording paper.

The head 1 has a sleeve 11 as a developer supply means for supplying the toner 7 charged to a negative charge, and a developer passage control means for controlling the passage of the toner 7 supplied by the sleeve 11. Component 1
And a developer passing member 17. The developer passage member 17 has a plurality of developer passage holes 17a, 1
, And a control electrode 17b is arranged so as to surround each developer passage hole 17a constituting the developer passage hole array. A back electrode 23 is provided at a position facing the head 1 with the intermediate image holding belt 2 interposed therebetween.

In the image forming apparatus, an electric field is generated by applying a voltage to the control electrode 17b, and the toner 7 supplied by the sleeve 11 flies by the action of the electric field. The toner 7 flying from the sleeve 11 passes through the developer passage hole 17a, and after that, is attracted by the electric field formed by the back electrode 23 and adheres to the intermediate image holding belt 2. The flying of the toner 7 is controlled by controlling the voltage applied to the control electrode 17b.
An image is formed thereon.

However, in the conventional image forming apparatus, as the image formation is continued, the periphery of the developer passage hole 17a on the side of the sleeve 11, the inner wall of the developer passage hole 17a, or the intermediate image of the developer passage hole 17a. There is a problem that the toner 7 gradually accumulates around the holding belt 2 side, and the developer passage hole 17a is finally closed by the toner 7.

In order to solve such a problem, conventionally,
For example, as shown in Japanese Patent Laid-Open No. 4-80053,
There has been proposed an apparatus in which a vibration mechanism is provided in the developer passage control means, and the developer passage control means is vibrated by the vibration mechanism. According to this configuration, since the electrode surface is always vibrated by the vibration by the vibration mechanism and a mechanical action is given, the toner does not adhere to the developer passage control means. It is also possible to remove it immediately.

[0007]

However, the above-mentioned proposal does not consider generation of a standing wave of vibration by the vibrating mechanism. For this reason, there has been a problem that the toner cannot be removed at the node of the standing wave, causing uneven cleaning.

The present invention has been made in view of such circumstances, and an object of the present invention is to eliminate the problem of uneven cleaning by utilizing vibration in which a standing wave does not occur.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a developer supply means for supplying a developer, and a plurality of developer supply means arranged along at least the developer supply means. A developer passage control means for electromagnetically controlling a developer passing through these developer passage holes in accordance with an image signal; and a developer passing through the developer passage holes. Image receiving means, suction means disposed on the back side of the image receiving means for sucking the developer, vibration generating means for generating vibration, and the developer passing control means in parallel with the developer passing hole. And a vibration transmitting unit connected to the vibration generating unit, wherein the vibration generated by the operation of the vibration generating unit is transmitted to the developer passage control unit by the vibration transmitting unit. Said shake Vibration generating means for generating is a random vibration frequency component is not specified.

According to the second aspect of the present invention, the vibration generating means comprises a bending vibration generating means for generating a bending vibration.

In the invention according to claim 3, the vibration generating means includes a pressurizing means for applying a compressive stress to the bending wave generating means in a vibration direction of the bending wave generating means in a free state in which no vibration is generated. Have.

According to the fourth aspect of the present invention, the vibration generating means comprises a plurality of flexural vibration generating means arranged in a stacked manner.

[0013] In the invention according to claim 5, the vibration generating means is removable.

According to the constructions of the present invention, it is possible to generate a vibration without a standing wave on the vibration transmitting means, to eliminate insufficient cleaning at a node of the standing wave, and to achieve a more stable developer passage. The holes can be cleaned.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an image forming apparatus according to an embodiment of the present invention, in which 1 is a head having a sleeve 11 as a developer supply unit, 2 is an intermediate image holding belt as an image receiving unit, and 3 is the intermediate image holding belt. Transfer means 4 for transferring the image formed on the belt 2 to the recording paper 5;
Is a fixing unit for fixing the image transferred by the above on the recording paper 5. The four heads 1 are provided. Each of the heads 1 stores a toner as a developer of yellow, magenta, cyan, and black, respectively. The image forming apparatus can form a color image. It is configured. Incidentally, the toner has an average diameter of about 10 μm, and such a diameter can be measured by a small-hole passing method (using a multisizer manufactured by Coulter Inc.).

The intermediate image holding belt 2 is of an endless type, and is provided with a belt driving roller 21 for driving the intermediate image holding belt 2 and a ground roller 22. A back electrode 23 and a power supply 24 are provided on the back of the intermediate image holding belt 2.
Are arranged at positions facing each of the heads 1.

Further, the intermediate image holding belt 2 is provided with a belt cleaning 25 pressed against the intermediate image holding belt 2 at a position facing the belt driving roller 21. The toner or dirt forming an image on the intermediate image holding belt 2 is removed after passing through the transfer unit 3.

As the intermediate image holding belt 2, for example, a belt obtained by dispersing conductive carbon in a polycarbonate having a thickness of about 150 μm may be used, and its circumference may be set to about 340 mm for A4 size paper. . The belt drive roller 21 and the ground roller 22 include:
Both may have a diameter of about 25 to 30 mm. In addition, as the back electrode 23, a metal plate or a film in which a conductive filler is dispersed in a resin may be used.
The voltage may be set to about 2000 V, preferably 1000 V.

The transfer means 3 includes a transfer roller 31 disposed opposite to the ground roller 22, and the transfer roller 31 is configured to be able to freely contact and separate from the ground roller 22. Further, a transfer power supply 32 is connected to the transfer roller 31, and an electric field is generated by applying a voltage to the transfer roller 31 so that the toner on the intermediate image holding belt 2 is attracted to the recording paper 5 side. I have. The transfer unit 3 transfers the image on the intermediate image holding belt 2 to the recording paper 5 by bringing the intermediate image holding belt 2 and the recording paper 5 into close contact between the transfer roller 31 and the ground roller 22. .

As the transfer roller 31, for example, a roller having an outer diameter of about 20 mm formed by winding a urethane sponge around a shaft core having a diameter of 8 mm is used.
Should be set to about 10 ⁷ Ω at the time of application.

The fixing means 4 comprises a fixing roller 41 and a pressure roller 42, which are disposed opposite to each other.
A heat source 41a is provided inside the fixing roller 41, and the heat generated by the heat source 41a causes the fixing roller 41a.
Is kept heated at a high temperature. The fixing unit 4 applies heat to the recording paper 5 by applying heat from the fixing roller 41 and pressure from the pressing roller 42 and the fixing roller 41 to melt the toner and
To be established.

As shown in FIG. 2, the head 1 is provided with a hopper 14 for storing the toner 7, a sleeve 11 provided on a side of the hopper 14, and abutting on the sleeve 11. Toner regulating blade 12
A toner supply roller 13 disposed opposite to the sleeve 11, and a toner supply roller 13 disposed in the hopper 14,
A stirring means 15 for stirring the toner 7 is arranged in the frame 16.

The sleeve 11 is formed in a cylindrical shape, and conveys the toner 7 by rotating in the counterclockwise direction in FIG. 2 (see the arrow in FIG. 2) while carrying the toner 7. Although the sleeve 11 is grounded (see FIG. 1), a DC or AC voltage may be applied to the sleeve 11.

The sleeve 11 is made of, for example, a metal such as aluminum or iron, an alloy or rubber, and has an outer diameter of 16 to 20 mm and a thickness of 1 m.
m. The rotational speed of the sleeve 11 may be set to, for example, a peripheral speed of 20 to 400 mm / sec.

The toner regulating blade 12 forms a toner layer of the toner 7 on the sleeve 11 and charges the toner 7 by friction. The toner regulating blade 12 comes into contact with the sleeve 11 in a counter direction of the rotation direction. It is arranged. The toner regulating blade 12 charges the toner 7 to a negative polarity, and sets the toner layer formed on the sleeve 11 to one layer. Such a toner regulating blade 12 may be configured by attaching an elastic member such as a urethane rubber sheet to a phosphor bronze plate material, for example.

The supply roller 13 supplies the toner 7 to the sleeve 11 and is disposed so as to contact the sleeve 11 on the outer peripheral surface. The supply roller 13 is configured to rotate in the opposite direction (clockwise direction in FIG. 2) with respect to the sleeve 11, and the amount of bite of the supply roller 13 into the sleeve 11 is, for example, 0.1 to 0. It is preferred to be about 2 mm. As such a supply roller 13, for example, a roller obtained by winding a synthetic rubber such as a urethane sponge around a metal core may be used, and its outer diameter may be formed, for example, to about 12 mm.

Then, the toner 7 in the hopper 14 is agitated by the agitating means 15 and thereafter, the supply roller 13
The sleeve 11 and the sleeve 11 rotate with each other, so that the sleeve 11 is supported on the surface of the sleeve 11. Further, excess toner among the toner carried on the surface of the sleeve 11 is dropped by the toner regulating blade 12, and the toner 7 carried on the sleeve 11 is charged to a negative polarity.

In the present embodiment, the sleeve 11 is used as the developer supply means. However, such a sleeve 11 is not necessarily used as the developer supply means. Alternatively, a screw-type carrier or the like may be used as the developer supply unit.

As shown in FIG. 3, the head 1 has an FP as a developer passing member which constitutes a developer passing control means opposed to the sleeve 11 at the opening of the frame 16.
C17 (Flexible Print Circuit = Flexib
le Print Circuit). This FPC17
The insulating member 17c is provided with a developer passage hole 17a through which the toner passes. An electric field for pulling the toner 7 carried on the sleeve 11 is provided around the sleeve 11 around the developer passage hole 17a. Control electrode 1 for generating
7b is provided. On the other hand, the developer passage hole 17a
And an electric field for preventing the toner passing through the developer passage hole 17a from spreading and flying on the surface opposite to the sleeve 11 (on the side of the intermediate image holding belt 2). A guard electrode 17d may be provided. The control electrode 17b and the guard electrode 17d are both coated with resin coating layers 17e and 17f, respectively.

As such an FPC 17, for example, the insulating member 17c may be formed of a polyimide resin.
The thickness may be set to 10 to 70 μm. Further, the diameter of the developer passage hole 17a may be, for example, 50 to 200 μm, and is preferably set to 130 μm. The control electrode 17b and the guard electrode 17d are both set to a thickness of 10 μm and may be made of, for example, copper.
The resin coating layers 17e and 17f may be set to a thickness of 1 to 2 μm.

Further, the FPC 17 is provided on the insulating member 1.
When 7c is made of a polyimide resin, it has viscoelasticity. Although not shown, this FPC
One end of 17 is fixed, while the other end is pulled by, for example, a spring member, so that tension acts on the FPC 17.

Further, the voltage applied to the control electrode 17b may be set to, for example, 300 V or less, and the voltage applied to the guard electrode 17d may be, for example, -10.
Setting to 0V is good.

As shown in FIG. 4, the FPC 17 has the plurality of developer passage holes 17a, 17a,... Arranged in a row to form, for example, one row of developer passage holes 17g. In this embodiment, the case where the developer passage hole row 17g is one row is shown, but the invention is not limited to this.
There may be two or more rows.

In the FPC 17, a vibration transmitting means 63 is disposed in parallel with the developer passage hole row 17g. This vibration transmitting means 63 is an FPC
It is formed in a rod shape or a plate shape having the same length as the width of the FPC 17 and is adhered to the FPC 17. Such bonding may be performed by, for example, thermocompression bonding or an epoxy adhesive. In this embodiment, the length of the vibration transmitting means 63 is the same as the width of the FPC 17,
Of course, they may be different.

A bending vibration generating means 61 for generating vibration is provided on the vibration transmitting means 63. The vibration generating means 61 may be any means that transmits the generated vibration to the vibration transmitting means 63 and generates vibration on the vibration transmitting means 63. For example, titanium zirconate lead (PZ
A flexural vibration is generated by a lateral piezoelectric effect using a piezoelectric element such as T). The vibration generating means 61 may be provided together with or independently of the vibration transmitting means 63, if necessary, by an FPC.
If the device can be detached from the FPC 17, even if the service life of the vibration generating means 61 is shorter than that of the FPC 17 or the like, the service life of the entire apparatus can be extended by replacement.

Further, as shown in FIG.
Pressurizing means 65 for applying a compressive stress on the vibration member 1 in the vibration direction.
May be provided to prevent the vibration generating means 61 from being broken.

The vibration transmitting means 63 may have any rigidity capable of transmitting the vibration without absorbing the vibration, and may be formed of a metal such as stainless steel. Moreover, the board width is 5 mm and the board thickness is 0.3 m.
m may be set.

Next, the image forming operation of the image forming apparatus according to the above embodiment will be described, and its operation and effect will be described. First, when a predetermined voltage (for example, 200 V) is applied to the control electrode 17b by an image signal from the outside, an electric field is formed between the control electrode 17b and the sleeve 11, and the electric field is applied to the sleeve 11 by the electric field. The applied toner is pulled, and the toner pulled by the electric field passes through the developer passage hole 17 a of the FPC 17. The toner that has passed through the developer passage hole 17 a is pulled toward the intermediate image holding belt 2 by the electric field formed by the back electrode 23 and adheres to the intermediate image holding belt 2. On the other hand, when a voltage equal to or less than a predetermined value is applied to the control electrode 17b, an electric field is not formed between the control electrode 17b and the sleeve 11, so that the toner carried on the sleeve 11
It is carried on. For this reason, the toner does not adhere to the intermediate image holding belt 2.

As described above, by controlling the voltage applied to the control electrode 17b provided in each developer passage hole 17a of each head 1, toner is adhered to the intermediate image holding belt 2 to form an image. You.

During the period from the end of one unit of image forming processing to the next image forming processing (hereinafter referred to as a sheet interval), the vibration transmitting means 6 provided in the FPC 17 is provided.
A voltage is applied to the vibration generating means 61 on the third unit 3, and the vibration of the vibration generating means 61 is transmitted through the vibration transmitting means 63 to F
It is transmitted to the PC 17. It is needless to say that the timing of the application is not limited to the time between sheets, and may be applied during image formation.

By transmitting the vibration generated by the operation of the vibration generating means 61 to the FPC 17 by the vibration transmitting means 63, the vibration is transmitted to the developer passage hole 1 on the FPC 17.
7a, the adhesive force of the toner to the FPC 17 is cut off, and the toner adhered and deposited on the FPC 17 is removed. This can eliminate the clogging of the developer passage hole array 17g.

At this time, the signal input to the vibrator generating means 61 is white noise so that a specific vibration mode is not formed. In this case, the vibration transmitting means 63, F
Since standing waves are not generated on the PC 17 and the developer passage hole array 17g, it is possible to statistically eliminate amplitude unevenness on the developer passage hole array 17g.

In the present embodiment, the input signal is white noise. However, the input signal may be an irregular signal whose frequency component is not specified, and the input signal randomly generates an arbitrary frequency band in time. Or a signal obtained by removing white noise from a specific frequency band by passing white noise through at least one of a high-pass filter, a low-pass filter, and a band-pass filter. Good. When the guard electrode 17d is provided, a larger vibration amplitude can be obtained due to the rigidity of the electrode material.

Therefore, by determining the input signal as in this embodiment, the vibration transmitting means 63 and the FPC 17
Also, it is possible to prevent a specific vibration mode from being generated on the developer passage hole array 17g.
Cleaning unevenness is eliminated.

In this embodiment, the flexural vibration generating means 61 composed of a single-layer piezoelectric vibrator is used. However, the present invention is not limited to this. The flexural vibration generating means 61 is composed of a laminated vibrator as shown in FIG. Vibration generating means may be used. By doing so, driving at a lower voltage can be realized. In particular, when an even number of laminated vibrators are used, the upper surface of the vibrator can be grounded, which is advantageous for the safety of the user.

[0046]

As described above, according to the present invention,
Since the signal input to the vibration generating means is an irregular signal whose frequency component is not specified, a specific vibration mode is prevented from being generated on the vibration transmitting means and the developer passage control means, so that there is no uneven cleaning. A cleaning system of the agent passage control means can be constructed. Therefore, the cleanability around the developer passage hole can be improved, and the reliability of the apparatus can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a head.

FIG. 3 is an enlarged sectional view showing a developer passage portion of a head.

FIG. 4 shows an F provided with a vibration generating means and a vibration transmitting means.
It is a perspective view showing PC.

FIG. 5 is a sectional view showing a pressurizing means.

FIG. 6 is an explanatory diagram showing details of a flexural vibration generating means in which a plurality of vibrators are stacked and arranged.

FIG. 7 is a cross-sectional view illustrating an image forming state in a conventional image forming apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 head 2 intermediate image holding belt 3 transfer means 4 fixing means 5 recording paper 7 toner 11 sleeve 17 FPC (developer passage member) 17a developer passage hole 61 vibration generation means 63 vibration transmission means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiko Hashimoto 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Term (reference) 2C162 AE09 AE25 AE31 AE94 AH02 AH03 AH12 AJ02 AJ07 CA02 CA12 CA22 2H029 DB00

Claims (5)

[Claims] 1. A developer supply means for supplying a developer, and at least a plurality of developer passage holes provided along the developer supply means, wherein a developer passing through the developer passage hole is provided. A developer passage control unit that electromagnetically controls the developer according to an image signal; an image receiving unit to which the developer that has passed through the developer passage hole is provided; and a suction unit that is disposed on a back surface of the image receiving unit and sucks the developer. Suction means, vibration generation means for generating vibrations, vibration transmission means provided on the developer passage control means in parallel along the developer passage hole, connected to the vibration generation means, An image forming apparatus configured to transmit a vibration generated by an operation of the vibration generation unit to a developer passage control unit by a vibration transmission unit, wherein the vibration generated by the vibration generation unit has an irregular frequency component that is not specified. Image forming apparatus which is a dynamic. 2. The image forming apparatus according to claim 1, wherein said vibration generating means comprises a bending vibration generating means for generating a bending vibration. 3. The image forming apparatus according to claim 2, wherein the vibration generating means applies a compressive stress to the bending vibration generating means in a vibration direction of the bending vibration generating means in a free state in which no vibration is generated. An image forming apparatus comprising: 4. An image forming apparatus according to claim 2, wherein said vibration generating means comprises a plurality of flexural vibration generating means arranged in a stacked manner. 5. An image forming apparatus according to claim 1, wherein said vibration generating means is removable.