JPH11272083A - Wet electrophotographic equipment - Google Patents

Abstract

(57) Abstract: The present invention relates to a new wet-type electronic device having a function of recycling a liquid toner when adopting a configuration in which a non-volatile, high-viscosity, high-concentration liquid toner is used as a liquid developer. The purpose is to provide a photographic device. A wet electrophotographic apparatus according to the present invention includes a photoreceptor on which an electrostatic latent image is formed, a pre-wet device for applying a pre-wet liquid film on the surface of the photoreceptor, and a toner particle of a liquid developer. A developing roller 40 that adheres to the photoconductor 10,
Applicator rollers 41 and 42 for applying the supplied liquid developer to the surface of the developing roller 40 are provided. The present invention further includes a recovery unit that recovers the liquid developer remaining on the surface of the developing roller 40 as a liquid toner having a diluted concentration, and the collected liquid toner having a diluted concentration and a high concentration of the predetermined concentration or more. A high-concentration liquid toner in which toner particles are dispersed is mixed at a predetermined ratio to reproduce a liquid toner having a predetermined concentration, and the reproduced liquid toner is reused as a liquid developer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet electrophotographic apparatus using a non-volatile, high-viscosity, high-concentration liquid toner, and more particularly to a wet electrophotographic apparatus capable of controlling a toner supply amount to a developing unit. About.

[0002]

2. Description of the Related Art In an electrophotographic apparatus in which an electrostatic latent image is formed on a photosensitive member (photosensitive drum), toner is adhered to the image, and the image is transferred to paper and fixed, a dry type using powder toner is widely used. Used.

However, the powder toner has a problem that the toner is scattered, and the toner particles have a particle size of 7 to 10 μm.
There is a problem that the resolution is poor due to the large value of m.
Therefore, when high resolution is required, a wet type using a liquid toner is used. This is because the liquid toner has toner particles as small as about 1 μm and the charge amount is large, so that disturbance of the toner image hardly occurs and high resolution can be realized.

In a conventional wet-type electrophotographic apparatus, a low-viscosity liquid toner in which a toner is mixed with an organic solvent at a ratio of 1 to 2% is used as a developing solution. However, such a developer uses an organic solvent that is harmful to the human body and uses a large amount of the organic solvent because of its low toner concentration, which has a serious problem of causing environmental problems.

[0005] Against this background, a wet type using a high-viscosity, high-concentration developer constituted by dispersing a high-concentration toner in silicon oil or the like is described in International Publication No. WO95 / 08792. An invention of an electrophotographic apparatus has been disclosed.

The use of this liquid toner has the advantages that the problem of harm to the human body does not occur, and the high toner concentration eliminates the need to use a large amount of developer.

In the case of using such a non-volatile liquid toner having a high viscosity and a high concentration, it is very convenient to provide a function of recycling the liquid toner. Generally, in a dry-type electrophotographic apparatus using a powder toner, the idea of recycling the powder toner is not required in principle. This is because the powder toner is not diluted. That is, in a dry-type electrophotographic apparatus, the toner is supplied to the photoconductor by supplying powder toner to the developing roller while frictionally charging using a blade, and the development transferred to the photoconductor is performed. Only the process of supplying powder toner to the roller portion is performed.

On the other hand, when the liquid toner is recycled and reused in a liquid electrophotographic apparatus using the liquid toner, the ratio of the solid content of the liquid toner to the carrier changes because the liquid toner is diluted. Therefore, the collected liquid toner cannot be used as it is.

[0009] International Publication No. WO95 / 08792 does not adopt a configuration in which the liquid toner is recycled in accordance with an extension of the prior art.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has been made in consideration of a case where a configuration using a non-volatile, high-viscosity, high-concentration liquid toner is employed.
An object of the present invention is to provide a new wet type electrophotographic apparatus having a recycling function of controlling a toner supply amount to a developing device so as to regenerate a collected diluted liquid toner into a liquid toner having a predetermined concentration.

Further, according to the present invention, when controlling the toner replenishment amount to the developing device, the consumption amount of the toner particles is known and the replenishment amount is determined, whereby the toner concentration is stabilized without changing. It is intended to provide images.

[0012]

FIG. 2 shows the overall structure of a wet electrophotographic apparatus according to the present invention. The photoconductor 10 is
After being charged to about 700 V by the charging device 11, it is exposed by the exposure device 12, and the potential of the exposed portion becomes about 1
An electrostatic latent image of 00V is formed.

The pre-wetting device 13 applies a silicon oil having a viscosity of about 2.5 cSt or a viscosity of about 20 cSt which is the same as that of the carrier to a thickness of 4 to 5 μm on the surface of the photoreceptor 10.

The developing device 14 is provided in association with yellow / magenta / cyan / black, is biased with respect to the photosensitive member, and has a toner viscosity of 400 to 4000 mPa.
In S, a non-volatile, high-viscosity, high-concentration liquid toner having a carrier viscosity of 20 cSt is used as the liquid developer. The supply of the developer is carried out by using an applicator roller to transport the toner while thinly extending from the toner pool.
m is formed, and then the positively charged toner is supplied to the photoconductor 10 in accordance with an electric field between the photoconductor 10 and the photosensitive layer. The toner is applied to the exposed portion of the body 10.

The recovery means recovers the liquid developer remaining on the surface of the developing roller as a liquid toner having a dilute concentration, and the regenerating means makes the collected liquid toner having a dilute concentration and a high-density liquid having a predetermined concentration or higher. A high-concentration liquid toner in which toner particles are dispersed at a predetermined concentration is mixed at a predetermined ratio to regenerate a liquid toner having the predetermined concentration as a liquid developer, and the regenerated liquid toner is used as the liquid developer. use.

Further, the means for regenerating the liquid toner includes:
Means for calculating a print duty based on the print data;
It comprises means for calculating the amount of liquid toner consumed based on the printing duty and development efficiency from the calculating means, and determining the supply amounts of the carrier and toner particles.

In the high-concentration liquid toner mixed with the collected diluted-concentration liquid toner, the toner particles and the carrier can be separately supplied.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail according to embodiments. In the present invention, a non-volatile, high-viscosity, high-concentration liquid toner is used as a liquid developer. The liquid toner is obtained by dispersing toner particles such as a pigment in a liquid carrier (oil). It is.

FIG. 2 shows the overall structure of a wet electrophotographic apparatus provided with the present invention. As shown in FIG. 1, a wet electrophotographic apparatus according to the present invention includes a photosensitive member 10 and a charging device 11.
, An exposure device 12, a pre-wet device 13, a developing device 14, an intermediate transfer member 15, a blade 16, a charge removing device 17, a heating device 18, and a pressure roller 19.

The charging device 11 applies a voltage of about 700 V
To be charged. The exposure device 12 forms an electrostatic latent image on the photoconductor 10 by exposing the photoconductor 10 using a laser beam having a wavelength of 780 nm so that the potential of the exposed portion becomes about 100 V.

The pre-wetting device 13 applies a silicon oil having a viscosity of about 2.5 cSt or a viscosity of about 20 cSt, which is the same as that of the carrier, to a thickness of 4 to 5 μm on the surface of the photoreceptor 10. Here, the pre-wet device 13 may execute the pre-wet process before the exposure process performed by the exposure device 12, or may execute the pre-wet process after the exposure process.

The developing device 14 is provided in association with yellow / magenta / cyan / black, is biased to about 400 V, and has a toner viscosity of 400 as shown in FIG.
The liquid toner having a carrier viscosity of 20 cSt at ４4000 mPa · S is transported while being thinly extended from the toner pool using the applicator rollers 41 and 42, so that the toner layer having a thickness of 2 to 3 μm is formed on the developing roller 40. Is formed, and the positively charged toner is supplied to the photoconductor 10 according to the electric field between the photoconductor 10 and the toner is attached to the exposed portion of the photoconductor 10 charged to about 100V. .

According to the pre-wet layer applied by the pre-wet device 13, the toner can be prevented from adhering to the non-exposed portion of the photoconductor 10. The intermediate transfer member 15 is biased to about −800 V, and transfers the toner attached to the photoconductor 10 according to the electric field between the intermediate transfer member 15 and the photoconductor 10. The intermediate transfer member 15 first transfers yellow toner adhered to the photoreceptor 10, and then,
The magenta toner adhered to the photoconductor 10 is transferred, the cyan toner adhered to the photoconductor 10 is subsequently transferred, and the black toner adhered to the photoconductor 10 is subsequently transferred. .

The blade 16 removes toner and pre-wet liquid remaining on the photoreceptor 10. The neutralization device 17 neutralizes the photoconductor 10. The heating device 18 is used for the intermediate transfer member 15.
By heating the surface, the toner attached to the intermediate transfer member 15 is melted. The pressure roller 19 fixes the toner of the intermediate transfer body 15 melted by the heating device 18 on the print medium. Thus, the heating device 18 and the pressure roller 19
, The toner adhered to the intermediate transfer body 15 is melted and fixed to the print medium without heating the print medium, so that print media other than paper can be handled.

FIG. 1 exemplifies a configuration in which the developer is collected and reused. The liquid toner of the present invention is formed by dispersing solid particles (eg, pigment) in an insulating liquid (carrier agent), and has a viscosity of 100 to 100.
It has a high viscosity of 00 mPa · S. In order to use this liquid toner as a liquid developer, a thin layer of 1 to 50 μm is applied on the developing roller 40 and sent to the developing gap.

The liquid developer remaining on the developing roller 40 after passing through the developing gap portion is scraped off by the blade 45 and stored in the collecting portion 43. This is because solid particles move onto the photoreceptor 10. , And further diluted by the mixing of pre-wet oil.

The diluted liquid developer is sent to the toner reservoir 44 using a pump or the like. Here, a high-density toner, which will be described in detail later, is supplied and mixed with the diluted toner to form a liquid toner having a predetermined density. The liquid toner having the predetermined concentration is, in this example,
The toner is supplied to the developing roller 40 while being thinly stretched from the toner reservoir 44 by an applicator constituted by the roller 41 and the roller 42. Thus, development is performed as described above.

FIG. 4 is a diagram for explaining the mixing of the collected diluted toner and the high-density toner in the toner reservoir 44 shown in FIG. A liquid toner having a solid content concentration of, for example, 20% is used in a liquid electrophotographic printer as a liquid developing solution. At this time, the carrier of the liquid toner is reduced by a substantially constant 10%, and The consumption of the solid content is the development efficiency (the ratio of the solid content actually moved to the solid content to be moved from the developing roller onto the photoconductor) and the printing duty (the ratio of the area to be printed to the image area). Suppose that

FIG. 4A shows a liquid toner having a predetermined concentration (20%) having a solid content of 20% and a carrier of 80%. When developing such a liquid toner as a liquid developer using a liquid electrophotographic printer, it is known that the developing efficiency of the image portion is usually about 70%. .
At this time, assuming that the print duty of the image is 50%, as shown by the hatched portion in FIG.
% Will be consumed. As a result, when collected by the blade of the developing roller, 10% of the carrier is consumed as described above, and 13% of the solid content is recovered from the original 20%, and 7% of the initial solid is consumed. It was done. Therefore, the collected liquid toner is a liquid toner diluted to 16% as shown in FIG.

Therefore, as shown in FIG.
For example, in a configuration in which high-concentration toner of 50% density is supplied to the diluted toner, by supplying less than 20% of the used toner amount, high-concentration toner is supplied.
It is possible to maintain the initial 20% as the toner concentration of the toner pool 44.

As described above, the solid content concentration of each color toner,
In a printer using a developing device whose development efficiency of the image portion is known, if the print duty can be obtained for each color, the amount of high-density toner whose density is known can be supplied to the toner pool 44 can be obtained. Instead of replenishing the high-density toner described above, it is also possible to separately replenish the respective amounts of the carrier and the solid. Even in this case, it is possible to always maintain the liquid toner of a predetermined concentration.

FIG. 5 is a schematic structural view of the means for determining the toner supply amount according to the present invention. Printing duty calculation means 46
Calculates the printing duty for each color before printing, when rasterizing the data from the host side at the printer side, or at the time when directly receiving bitmap data, as a means for calculating the printing duty. .
The consumption calculation unit 47 supplies high-density toner based on the print duty and development efficiency of each color,
Alternatively, the amount is determined on the assumption that the carrier and the solid content are individually replenished. Therefore, the toner concentration in the toner pool can be maintained without providing a sensor for detecting the carrier and the concentration ratio of the liquid toner in the liquid toner container.

FIG. 6 is a flowchart for explaining this printing operation. In step s1, the printer receives print data from the host. And
In step s2, the print data is rasterized. Alternatively, as described above, the bitmap data can be directly received from the host side. In step s3, before printing, the print duty for each color is calculated, and the supply amount of high density toner for each color is calculated. In step s4, printing is performed, and in step s5, the amount of high-density toner calculated in advance is supplied. Alternatively, as described above, it is also possible to configure so that the respective consumption amounts of the carrier and the solid content are separately supplied.

[0034]

According to the present invention, the recovering means recovers the liquid developer remaining on the surface of the developing roller as a liquid toner having a diluted concentration, and the reproducing means forms the recovered liquid toner having the diluted concentration with the predetermined density. A high-concentration liquid toner in which toner particles are dispersed at a high concentration equal to or higher than a concentration is mixed at a predetermined ratio to regenerate a liquid toner having the predetermined concentration as a liquid developing solution. Provided a new wet electrophotographic apparatus with a liquid toner recycling function when adopting a configuration that uses a high-viscosity, high-concentration liquid toner that exhibits non-volatility by being configured to be reused as a liquid developer. can do.

Further, according to the present invention, the print duty is calculated based on the print data, and the liquid toner consumption is calculated based on the calculated print duty and the development efficiency, so that the toner density is not directly detected. The amount of toner particles consumed can be known, and the amount of toner replenishment can be determined. This makes it possible to provide a stable image without changing the toner concentration in the toner pool every time printing is performed.

[Brief description of the drawings]

FIG. 1 illustrates a configuration for collecting and reusing a developer according to the present invention.

FIG. 2 is an overall configuration diagram of the wet electrophotographic apparatus of the present invention.

FIG. 3 is a diagram for explaining the operation of an applicator roller and a developing roller.

FIG. 4 is a diagram for explaining mixing of a collected diluted toner and a high-density toner.

FIG. 5 is a schematic configuration diagram of a unit for determining a toner supply amount according to the present invention.

FIG. 6 is a flowchart illustrating a printing operation.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 photoconductor (drum) 11 charging device 12 exposure device 13 prewetting device 14 developing device 15 intermediate transfer member (roller) 16 blade 17 static eliminator 18 heating device 19 pressure roller 40 developing rollers 41, 42 applicator roller 43 reservoir 44 Toner pool 45 Blade 46 Print duty calculation means 47 Consumption calculation means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shigeki Uesugi 98 Unoki-nu, Unoki-cho, Hebei-gun, Ishikawa Pref. Address No. 2 PFU Co., Ltd. (72) Inventor Genji Ichida Unoki-cho, Unoki-cho, Hebei-gun, Ishikawa 98-2 In Pfu Co., Ltd. 98-2 Inside PFU Co., Ltd. (72) Inventor Shigeharu Okano Unoki-ki, Unoki-cho, Hebei-gun, Ishikawa Prefecture 98-2 Inside PFU Co., Ltd. No. 98 No. 2 Inside PFU Co., Ltd.

Claims (5)

[Claims] 1. A wet electrophotographic apparatus using, as a liquid developer, a non-volatile, high-viscosity liquid toner in which toner particles are dispersed at a predetermined concentration in a liquid carrier, wherein an electrostatic latent image is formed. An image support, a pre-wet liquid application unit for applying a pre-wet liquid film on the surface of the image support, and a two-layer structure of a pre-wet liquid film on the image support. A developing roller for supplying a liquid developer in contact with the image support, and for applying toner particles of the liquid developer to the image support in response to an electric field generated between the image support and the developing roller; A developing solution application unit configured to include a plurality of rotating rollers connected to each other, to apply the supplied liquid developing solution to the surface while applying the liquid developing solution to the developing roller, and to apply the developing solution to the surface of the developing roller; roller A collecting means for collecting the liquid developer remaining on the surface as a liquid toner having a diluted concentration; a liquid toner having the collected diluted concentration; and a high-concentration liquid toner in which toner particles are dispersed at a high concentration equal to or higher than the predetermined concentration. And a means for regenerating the liquid toner having the predetermined concentration as a liquid developer by mixing the liquid developer at a predetermined ratio; and a means for using the regenerated liquid toner as the liquid developer. Wet electrophotographic apparatus. 2. The means for regenerating the liquid toner comprises: means for calculating a print duty based on print data; and means for calculating the amount of liquid toner consumed based on the print duty and development efficiency from the calculation means, thereby providing a carrier and a toner. 2. The wet electrophotographic apparatus according to claim 1, further comprising means for determining a replenishing amount of the particles. 3. The wet electrophotographic apparatus according to claim 2, wherein the calculation of the print duty is performed when rasterizing the received print data. 4. The wet electrophotographic apparatus according to claim 2, wherein the calculation of the print duty is performed based on the received bitmap data. 5. The wet electrophotographic apparatus according to claim 1, wherein the high-concentration liquid toner mixed with the collected diluted liquid toner is supplied with toner particles and a carrier separately.