JP2005004034A - Developer replenishing method, image forming method, developer, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developer replenishing method capable of forming a good quality image over a long period of time, and securing desirable electrification characteristics even at the time of life when a lubricant is used. <P>SOLUTION: After carrying out development using a developer containing toner particles and a fatty acid metal salt added to the toner particles as an initial developer, the developer that contains the toner particles which has less fatty acid metal salt than the initial developer added, or which has no fatty acid metal salt added is replenished as a replenishing developer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【表２】

上述の実施例では、滑材として、ステアリン酸亜鉛を使用したが滑剤としてはこれに限られることなく、公知の材料各種が使用できる。
【００４５】
脂肪酸金属塩としては、カルボン酸金属塩が使用でき、具体的には、ステアリン酸、パルミチン酸、ラウリル酸等が使用できる。中心金属としては、マグネシウム、アルミニウム、カルシウム、亜鉛等が使用できる。
【００４６】
またステアリン酸亜鉛の添加量は、初期現像剤としては、０．０００１〜０．１重量％が適当である。これより少ないと、感光体表面削れが大きくなる。またこれより多いと、現像の初期段階で帯電不良を起こしやすく適当ではない。
【００４７】
またステアリン酸亜鉛の平均粒径は、１〜１００μｍが好ましく用いられる。１μｍ未満となると、現像の初期段階で帯電不良を起こしやすい。また１００μｍを超えると、現像の初期段階で、滑剤が感光体に付着し、画像上に白斑が現れる現象がおきやすくなるので、適当ではない。
【００４８】
補給用現像剤に含まれる滑材の量は、全く含まれないものとするか、初期現像剤よりも少量とすべきである。少量とした場合は、上述した通り、現像装置の構成や、現像剤材料の種類などにより調整して設定すべきである。
【００４９】
以上説明した通り、本発明の実施例によれば、長期にわたって、感光体削れと、カブリの発生を防止して良好な画像を形成することができる。
【００５０】
尚、本発明は上述の実施例に限られることなく、本発明の趣旨を逸脱しない範囲で変形可能なことは言うまでもない。
【００５１】
【発明の効果】
以上説明した通り、本発明によれば、滑剤を使用した場合、ライフ時にも良好な帯電性を確保でき、長期に渡り良好な画像を形成することができる。
【図面の簡単な説明】
【図１】本実施例にかかる画像形成装置の断面図である。
【図２】本実施例にかかる現像剤と、比較例にかかる現像剤の評価結果である。
【図３】本実施例にかかる現像剤と、比較例にかかる現像剤の評価結果である。
【図４】本実施例にかかる現像剤と、比較例にかかる現像剤の評価結果である。
【符号の説明】
１・・・・感光体
５・・・・現像装置
２１・・・トナー補給部
２３・・・トナー混合部
２９・・・リサイクル装置
Ｄ・・・・初期現像剤
Ｔｓ・・・補給用現像剤[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a developer replenishing method, an image forming method and a developer used in dry electrophotographic apparatuses such as copying machines and printers, and an image forming apparatus using these.
[0002]
[Prior art]
In dry developers, it has been conventionally known that the surface of a photoreceptor can be prevented from being worn by friction with a developer or a cleaning blade by adding a so-called lubricant such as a fatty acid metal salt to toner particles. (For example, refer to Patent Document 1.)
[0003]
However, the toner to which the fatty acid metal salt is added has low fluidity and poor chargeability. As for the chargeability, since the carrier in the developer also deteriorates as the use proceeds, the contact charge between the toner and the carrier becomes insufficient, and the chargeability of the toner at the time of life becomes worse.
[0004]
Therefore, in a copying machine or the like that replenishes and uses toner, it has been required to ensure the chargeability of the toner during the life.
[0005]
[Patent Document 1]
JP 2000-89502 A (first page)
[0006]
[Problems to be solved by the invention]
As described above, the developer containing the fatty acid metal salt has a drawback that the fluidity is lowered and the chargeability at the time of life is deteriorated.
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to provide a developer replenishing method and an image forming method capable of eliminating the above-described drawbacks and ensuring good chargeability during life.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides, as an initial developer, after developing with a developer containing toner particles and a fatty acid metal salt added to the toner particles, A developer containing toner particles in which the amount of the fatty acid metal salt is less than that of the initial developer or the fatty acid metal salt is not added at all is used.
[0009]
According to the present invention, after the electrostatic latent image formed on the image carrier is developed with a developer, unnecessary developer on the image carrier is removed, and the removed developer is again used as a developer for development. In the image forming method to be reused as a replenisher, a developer having toner particles and a fatty acid metal salt added to the toner particles is used as an initial developer, and replenishment is performed after development with the initial developer. There is provided an image forming method using a developer containing toner particles in which the amount of the fatty acid metal salt is less than that of the initial developer or the fatty acid metal salt is not added at all.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0011]
A copying machine will be described as an example of an image forming apparatus to which the present invention is applied. FIG. 1 is a sectional view of a main part of a copying machine shown as an embodiment.
[0012]
The main part of the copying machine shown in FIG. 1 has a photoreceptor 1 as an image carrier. The photoreceptor 1 rotates in the direction of the arrow a in the figure.
[0013]
Around the photosensitive member 1, there are a charging charger 2, an exposure device 3 for exposing the charged photosensitive member 1 to the laser beam B to form an electrostatic latent image, a developing device 5 for developing the electrostatic latent image, and a developer image. A transfer device 7 for transferring the toner onto the paper, a peeling device 9 for peeling the paper from the photosensitive member 1, a cleaning device 13 for cleaning the residual developer on the photosensitive member 1, and the like are disposed. The cleaning device 13 includes a cleaning blade 15 that contacts the photosensitive member and removes the developer on the photosensitive member, and a static elimination lamp 16 that neutralizes the photosensitive member 1 from which the developer has been removed.
[0014]
The sheet is taken out from a sheet feeding cassette (not shown) and conveyed toward the photosensitive member 1 by a conveying roller 17 or the like. The sheet on which the developer image on the photoconductor is transferred by the transfer device 7 is conveyed by a conveyance belt 19 toward a fixing device (not shown).
[0015]
The developing device 5 contains a developer D as an initial developer. Developer D is a two-component developer composed of toner and carrier. The developer D will be described in detail later.
[0016]
Above the developing device 5, a toner replenishing unit 21 that contains a replenishment developer is provided in order to replenish the amount of initial developer consumed in development. A toner mixing unit 23 is provided between the toner supply unit 21 and the developing device 5. A recycling device 29 is provided between the toner mixing unit 23 and the cleaning device 13 for supplying the used developer collected by the cleaning device 13 to the toner mixing unit 23 and reusing the developer. ing.
[0017]
The developing device 5 contains a developer D containing toner and a carrier as an initial developer, and has a developing roller 33 facing the photosensitive member. In the developing device 5, a stirring roller 35 for stirring the developer D in the developing device 5 and a supply roller 37 for supplying the developer stirred by the stirring roller 35 to the developing roller 33 are provided. It has been. A sensor 38 that determines the mixing ratio of the toner and the carrier in the developing device 5 based on the magnetic permeability is disposed below the stirring roller 35. In addition, a doctor blade 39 for forming a thin layer of the developer D supplied from the supply roller 37 on the developing roller is disposed facing the developing roller 33.
[0018]
Toner supply unit 21 accommodates the replenishment toner T _S therein. In addition, the toner replenishing unit 21 includes a toner replenishing roller 41 for supplying toner to the toner mixing unit 23. The toner T _S stored in the toner replenishing section 21 by the rotation of the toner supply roller 41, an appropriate amount is dropped into the toner mixing portion 23.
[0019]
The toner mixing portion 23, the toner T _S is supplied, it is conveyed recycled toner Tr is supplied by the recycling device 29. Toner mixing portion 23 includes a toner T _S, the mixing rollers 51 for mixing and stirring the recycled toner Tr. In the toner mixing unit 23, a sensor 53 for detecting the amount of toner in the toner mixing unit 23 is provided. Based on the toner amount detection result by the sensor 53, the toner supply roller 41 is driven to rotate. Further, based on the toner amount detection result by the sensor 38, the mixing roller 51 rotates and the toner in the mixing unit 23 is supplied into the developing device 5.
[0020]
The recycling apparatus 29 includes a transport auger 62 and transports the developer removed by the cleaning blade 15 to the toner mixing unit 23 by the rotation of the transport auger 62.
[0021]
Here, the developer D will be described in detail. The developer D is composed of toner and a carrier as an initial developer, and the developer D is accommodated in the developing device 5. The toner T includes toner particles containing a colorant such as a resin and carbon black, a charge control agent, wax, and the like, and silica or a fatty acid metal salt externally added to the surface of the toner particles. In this embodiment, zinc stearate is used as the fatty acid metal salt.
[0022]
The average particle diameter of zinc stearate is 4 μm. The addition amount was set to 0.0001% by weight ratio with respect to 100 parts by weight of toner T.
[0023]
The replenishing toner T _S, as well as the toner T which constitutes the developer D, a resin, a colorant, a charge control agent, a wax, are constituted of silica, fatty acid metal salt is not externally added. Replenishing toner T _S is optionally be replenished to the toner replenishing section 21.
[0024]
The toner is produced by melting and kneading a resin, a colorant, a charge control agent, and a wax, cooling, pulverizing, and classifying to obtain toner particles of about 10 μm, and then adding silica and a fatty acid metal salt to the toner particles. The toner was added. The carrier is not particularly limited, and in this embodiment, a ferrite carrier is used.
[0025]
The operation of the image forming apparatus configured as described above will be described.
[0026]
First, when the photosensitive member 1 starts rotating, charging is performed by the charging charger 2, and the laser beam B corresponding to the image is exposed to the charged photosensitive member 1 by the exposure device 3 to form an electrostatic latent image. This electrostatic latent image is developed with the developer D accommodated in the developing device 5. The developer image formed on the photoconductor is transferred onto a sheet by the transfer device 7, is charged by the peeling device 9, is peeled off from the photoconductor 1, and is transported by the transport belt 19.
[0027]
The developer remaining on the photoreceptor 1 after the developer image is transferred is removed by the cleaning blade 15. Thereafter, the photoreceptor 1 is subjected to charge removal by the charge removal lamp 16 to complete one cycle of image formation, and is again charged by the charge charger 2.
[0028]
As the image is formed, the developer D in the developing device 5 is consumed, and the sensor 38 detects the mixing ratio of the toner and the carrier that fluctuates due to the consumption. Based on the detection result of the sensor 38, the toner is supplied from the toner mixing unit 23 into the developing device 5.
[0029]
In the toner mixing unit 23, the sensor 53 detects the toner amount, and based on this detection signal, the toner Ts is newly supplied from the toner supply unit 21.
[0030]
On the other hand, the toner removed by the cleaning blade 15 is transported and supplied into the toner mixing unit 23 by the rotation of the transport auger 62 in the recycling device 29. Accordingly, the toner supplied from the toner mixing unit 23 to the developing device 5 is a mixture of the toner Ts and the toner Tr.
[0031]
When image formation is started, the toner T adheres to the photosensitive member 1 and is slid in contact with the cleaning blade in a state where the toner is attached, so that a thin film of zinc stearate is formed on the photosensitive member 1. The However, once the film is formed, most of the film is scraped and removed when it comes into sliding contact with the cleaning blade again. For this reason, it is necessary to continuously supply zinc stearate onto the photoreceptor 1 in some form.
[0032]
In this embodiment, by adopting recycle development, the removed zinc stearate is supplied again into the developing device 5.
[0033]
When recycling is performed, as the image formation is repeated, the zinc stearate is gradually reduced as it adheres to the transfer auger 62 or is transferred onto the paper.
[0034]
By the way, as the image formation progresses, the carrier also deteriorates. Needless to say, the deterioration of the carrier deteriorates the chargeability of the toner, but it has been found that the addition of zinc stearate also causes the chargeability to deteriorate. Therefore, in the present invention, the amount of zinc stearate in the developer D is gradually decreased by using toner to which zinc stearate is not added as a replenishing developer. In other words, zinc stearate is contained only in the initial developer, and this content is gradually reduced by attaching it to the transport auger 62 or transferring it to the paper. Yes.
[0035]
This makes it possible to cover the deterioration of chargeability due to carrier deterioration. Therefore, the chargeability of the toner can be kept above a certain level over a long period of time.
[0036]
The important thing is that the amount of zinc stearate gradually decreases in parallel with the deterioration of the carrier. From this viewpoint, the zinc stearate contained in the replenishment developer is not contained at all. Alternatively, it may be possible to add a smaller amount than the initial developer. The addition amount should be appropriately set according to the characteristics of the developing device.
[0037]
2 to 4 show the evaluation results of the developer characteristics and the obtained images when the copy test is repeatedly performed by the copying machine having the above-described configuration. FIG. 2 shows the variation of zinc stearate (lubricant amount) in the used developer (waste toner) removed by the cleaning blade 15. FIG. 3 shows the fluctuation of the fog value appearing in the copy image, and FIG. 4 shows the amount of abrasion on the surface of the photoreceptor.
[0038]
For comparison, the initial developer was not added with zinc stearate, and a developer with zinc stearate added only to the replenishment developer was prepared, and the evaluation results of the two were compared. To the developer for comparison, zinc stearate was added at a ratio of 0.0001% by weight with respect to 100 parts by weight of toner T. The evaluation result is represented by a solid line in the present example, and is represented by a broken line in the comparative example.
[0039]
As shown in FIG. 2, in this embodiment, while the number of copies is small, the initial developer containing zinc stearate is supplied onto the photosensitive member 1 and is scraped off by the cleaning blade. The amount of zinc stearate is also rising at a stretch. On the other hand, when a developer containing zinc stearate is used as the replenishment developer, the amount of zinc stearate in the waste toner starts to gradually increase as the number of copies increases, and exceeds about 100K sheets. The rate of increase has been gradual since hit.
[0040]
On the other hand, when the result of the fog value appearing in the copy image is compared, the amount of fog is larger in the present embodiment up to about 100K sheets, but in the present embodiment over the period from 100K sheets to 400K sheets. The amount of fog has decreased. However, even in this example, the amount of fog was not so large, and a sufficiently good image could be formed. Further, with the comparative developer, fogging started to be noticeable on 400K sheets or more.
[0041]
Further, with respect to the amount of abrasion of the photosensitive member, it is found that the amount of abrasion of the photosensitive member is smaller up to about 400K, and the amount of abrasion of the photosensitive member can be sufficiently reduced by the method of this embodiment.
[0042]
As shown in Tables 1 and 2, several developers were prepared with the same configuration as the above-described example, and only the average particle diameter and addition amount of zinc stearate were changed, and the test was performed in the same manner as in the above-described example. The results are shown.
[0043]
The fog is represented by ○ when the ratio of fog in the image is 2% or less, Δ by 2 to 3.5%, and x when it exceeds 3.5%. With respect to the abrasion on the surface of the photosensitive member, those having a abrasion amount of 15 μm or less are indicated by ◯, and those exceeding 15 μm are indicated by ×.
[0044]
[Table 1]

[Table 2]

In the above-described embodiment, zinc stearate is used as the lubricant, but the lubricant is not limited thereto, and various known materials can be used.
[0045]
As the fatty acid metal salt, a carboxylic acid metal salt can be used, and specifically, stearic acid, palmitic acid, lauric acid and the like can be used. As the central metal, magnesium, aluminum, calcium, zinc or the like can be used.
[0046]
The addition amount of zinc stearate is suitably 0.0001 to 0.1% by weight as the initial developer. If the amount is less than this, the surface of the photosensitive member is greatly scraped. On the other hand, if it is more than this, charging failure is liable to occur in the initial stage of development, which is not appropriate.
[0047]
The average particle diameter of zinc stearate is preferably 1 to 100 μm. If it is less than 1 μm, charging failure tends to occur in the initial stage of development. On the other hand, if the thickness exceeds 100 μm, it is not appropriate because the lubricant tends to adhere to the photoconductor and white spots appear on the image in the initial stage of development.
[0048]
The amount of lubricant contained in the replenishment developer should not be included at all or should be less than the initial developer. When the amount is small, as described above, it should be adjusted and set according to the configuration of the developing device, the type of developer material, and the like.
[0049]
As described above, according to the embodiments of the present invention, it is possible to prevent the photoconductor from being scraped and fogging and form a good image over a long period of time.
[0050]
Needless to say, the present invention is not limited to the above-described embodiments and can be modified without departing from the spirit of the present invention.
[0051]
【The invention's effect】
As described above, according to the present invention, when a lubricant is used, good chargeability can be ensured even during life, and a good image can be formed over a long period of time.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an image forming apparatus according to an embodiment.
FIG. 2 is an evaluation result of a developer according to the present example and a developer according to a comparative example.
FIG. 3 is an evaluation result of a developer according to the present example and a developer according to a comparative example.
FIG. 4 shows the evaluation results of the developer according to the present example and the developer according to the comparative example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Photoconductor 5 ... Development device 21 ... Toner replenishment part 23 ... Toner mixing part 29 ... Recycling device D ... Initial developer Ts ... Replenishment developer

Claims (4)

After developing with a developer containing toner particles and a fatty acid metal salt added to the toner particles as an initial developer, the amount of the fatty acid metal salt added as a replenishment developer is higher than that of the initial developer. A developer replenishing method comprising replenishing a developer containing toner particles containing little or no fatty acid metal salt. After developing the electrostatic latent image formed on the image carrier with a developer, the unnecessary developer on the image carrier is removed, and the removed developer is reused as a developer for development again. In the forming method,
As an initial developer, a developer having toner particles and a fatty acid metal salt added to the toner particles is used, and as a replenishment developer to be replenished after the development with the initial developer, And a developer containing toner particles in which the amount of the fatty acid metal salt is small or no fatty acid metal salt is added. A developer replenished as the initial developer having toner particles and a fatty acid metal salt added to the toner particles is consumed,
A developer containing the toner particles in which the amount of the fatty acid metal salt is less than that of the initial developer or the fatty acid metal salt is not added. Developing means for developing the electrostatic latent image formed on the image carrier;
Transfer means for transferring the developer image formed by the developing means onto an image forming medium;
Cleaning means for removing developer remaining on the image carrier after transfer by the transfer means;
A recycling means for supplying the developer removed by the cleaning means to the developing means;
Replenishing means for replenishing developer to the developing means;
The developing means contains a developer having toner particles and a fatty acid metal salt added to the toner particles as an initial developer,
The replenishing means accommodates a developer containing toner particles in which the amount of the fatty acid metal salt added is smaller than that of the initial developer or the fatty acid metal salt is not added at all as a replenishing developer. An image forming apparatus.

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