JP3342637B2 - Copier or printer using amorphous silicon photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner in a one-component or two-component developer used for an electrophotographic copying machine, a facsimile, and a printer, and more particularly to a system using an amorphous silicon photosensitive member. It concerns a suitable toner.

[0002]

2. Description of the Related Art Copiers and laser printers currently on the market are capable of forming an electrostatic latent image on a photoreceptor in a charging and exposing step and a latent image on the photoreceptor as a toner image in a developing step. 2. Description of the Related Art An electrophotographic method is widely used in which an image is formed, a toner image on a photoreceptor is transferred to paper in a transfer step, and an image is obtained through a fixing step using heat, pressure and the like.

In the electrophotographic method, the surface of the photoreceptor is deteriorated due to various causes such as corona exposure in a charging process and toner filming in a developing process in repeated use. Conventional selenium-based photoconductors and organic photoconductors do not have extremely high surface hardness, and contaminated surfaces are scraped off by various rubbing forces during the copying process. Did not appear. However, as described above, this type of photoreceptor does not have a high surface hardness, and thus has poor durability and requires a great deal of care in handling, which is troublesome. as a result,
The use of amorphous silicon photoreceptors has been strongly desired.

[0004] Amorphous silicon (hereinafter a-Si)
The photoreceptor is non-polluting, has high photosensitivity, and has a Vickers hardness of 15
It has many excellent properties such as durability and handleability, such as extremely hard as 00 to 2000, and is considered to be an ideal photoconductor material, and its practical use is spreading.

On the other hand, when the a-Si photoreceptor is repeatedly used, surface deterioration such as adsorption of moisture due to oxidation of the surface layer and adhesion of ionic substances generated by corona discharge has been observed. It is known that a clear image cannot be obtained, that is, a so-called image deletion phenomenon appears. In the case of the a-Si photoreceptor, the surface layer once deteriorated cannot be polished and cleaned by the rubbing force during the copying process because of its high hardness. Therefore, as a countermeasure, a heater was incorporated inside the photoconductor to heat the surface temperature of the photoconductor to 40 to 50 ° C., thereby preventing the occurrence of trouble. As an attempt to eliminate the heater, Japanese Patent Application Laid-Open Nos. 62-168161, 62-272275, 63-186252, and the like have proposed a structure of the surface layer of the a-Si photosensitive member. Not in.

[0006]

SUMMARY OF THE INVENTION The present invention provides a technique for appropriately polishing a deteriorated drum surface even when an amorphous silicon drum is used, so that a clear image can always be obtained without using a drum heater. It is intended to be.

[0007] If a drum heater is used in copiers and printers that are smaller and more personalized, the system becomes complicated. Further, there is also a problem that a certain time is required for the temperature of the heater to be increased, and a time (warm-up time) from when the power is turned on to when printing is performed is long, which requires power consumption. Further, when the photoconductor is heated, the temperature is increased to a temperature close to the Tg temperature (glass transition point temperature) of the toner, so that there is a problem that the toner is fixed on the surface of the photoconductor. As described above, the present invention has been made to solve these problems.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a method for producing a toner, which has a volume resistivity in the range of 10 ² to 10 ¹⁰ Ωcm and a particle diameter in a ratio to the average particle diameter of the toner. 100: 1 to 2: 1, more preferably 50: 1
Polishing / cleaning particles in the range of
By using a toner containing about 5% by weight and 0.3 to 2% by weight of silica fine powder, even when an amorphous silicon photoreceptor is used, the deteriorated photoreceptor surface can be appropriately polished and cleaned. It has been found that stable image formation is always possible even without a drum heater.

That is, the added abrasive particles are less likely to be transferred as compared with the toner, and remain on the surface of the photoreceptor. This feature is due to the low resistance of the toner and the optimal ratio between the particle size of the toner and the particle size of the polishing / cleaning agent.
That is, with respect to the particle size ratio, if the abrasive particles are too small relative to the toner, the abrasive particles are likely to be retained on the toner surface and move with the toner during development and transfer, and as a result, remain on the surface of the photoreceptor after transfer. The amount is small. Also,
If too large, white spots due to abrasive particles developed on the image area,
White spots occur. If the particle size ratio between the toner and the abrasive particles is appropriate, a large amount of the toner can be retained on the surface of the photoreceptor even after transfer without causing troubles such as white spots and white spots.

The resistance of the abrasive particles is 1 × 10 ² to 1 × 10 ¹⁰
The reason for limiting to Ωcm will be described below. It is generally known that in the transfer process, when the resistance of the non-transfer material is 10 ¹⁰ or more, the transfer efficiency is rapidly reduced. On the other hand, if the resistance is 10 ² or less, the chargeability of the toner is reduced, but sufficient developability cannot be obtained, depending on the amount of addition. Abrasives satisfying such conditions include silicon carbide (SiC), magnetite (Fe ₃ O ₄ ), titanium oxide (TiO ₂ ), tin oxide (SnO ₂ ), and inorganic powder subjected to a surface conductive treatment. .

[0011]

Embodiments of the present invention will be described below.

According to the present invention, in particular, the element ratio of the surface layer (outermost surface) of the amorphous silicon photoreceptor is determined by the composition formula [a-Si
₁ -x Cx: H], X is 0.95 ≦ X
<1, and the Vickers hardness of the outermost surface is 300 or less, the hardness of the surface layer in contact with the photoconductive layer is large, and the hardness gradually decreases toward the free surface side. In combination with the photoreceptor, excellent print quality with no image deletion occurs even in a print test in a high-humidity environment without a drum heater while maintaining the durability of the amorphous silicon photoreceptor. Can be held.

[0013]

【Example】

 Example 1 Hereinafter, an example of the present invention will be described in detail.

Styrene acrylic resin 100 parts by weight Nigrosine dye 3 parts by weight Polypropylene wax 5 parts by weight Carbon black 8 parts by weight A mixture having the above composition was melt-kneaded by a twin-screw extruder. This was cooled, finely pulverized by a jet mill through coarse pulverization and medium pulverization, and a toner having an average particle size of 7 μm was obtained. This toner has a hydrophobic silica of 0.5% and a volume resistivity of 10%.
2% of conductive TiO ₂ (particle size ratio with toner: 20: 1) having an average particle diameter of 0.35 μm at ³ Ωcm was added and mixed with a Henschel mixer. 5 parts by weight of the toner thus obtained is mixed with 95 parts by weight of a carrier to prepare a two-component developer, and a printer FS-15 equipped with an a-Si photosensitive member manufactured by Kyocera.
The image evaluation was performed using the sample No. 50. After printing 50,000 sheets in a normal environment, the temperature is 32.5 ° C and the humidity is 80% RH.
The sample was left in the environment for 10 hours, an image sample was taken, and the presence or absence of image deletion was confirmed. No image deletion phenomenon was observed. When the surface of the drum was observed, no surface abnormality such as a scratch was observed. Example 2 Styrene acrylic resin 100 parts by weight Magnetite 60 parts by weight Nigrosine dye 3 parts by weight Polypropylene wax 5 parts by weight A mixture having the above composition was prepared in the same manner as in Example 1 to prepare a toner having an average particle diameter of 7 μm. 0.5% of hydrophobic silica was added, and 1% of SiC having a particle diameter of 0.7 μm (particle diameter ratio: 10: 1) and a volume resistivity of 10 ⁵ Ωcm was added thereto, followed by mixing with a Henschel mixer. . After printing 50,000 sheets of this toner in a normal environment in a one-component development process modified from the printer FS-1550 equipped with an a-Si photoreceptor, the temperature was 32.5 ° C. and the humidity was 80% RH. After standing for 10 hours and performing image evaluation, no particular abnormality was observed. When the drum surface was observed, no surface abnormality such as a scratch was observed.

Example 3 In Example 2, 2% of TiC having an average particle size of 0.2 μm and a volume resistivity of 1.1 × 10 ³ Ωcm was added to the abrasive.
When a similar experiment was conducted, no abnormalities were found on the image and the drum surface.

Comparative Example 1 In place of SiC of Example 2, 2% of TiO ₂ having an average particle size of 0.5 μm and a volume resistivity of 4.5 × 10 ¹² Ωcm was added, and the image was evaluated. And clear images could not be obtained. Also, clouding was seen on the drum surface.

Comparative Example 2 In place of the SiC of Example 2, 1% of SiC having an average particle size of 0.05 μm and a volume resistivity of 2.3 × 10 ³ Ωcm was added, and the image was evaluated. No clear image was obtained. Also, clouding was seen on the drum surface.

Table 1 summarizes the experimental results of the above Examples and Comparative Examples.

[0019]

[Table 1]

[0020]

As described above, according to the present invention,
In a copying machine or a printer equipped with an a-Si drum, a heaterless system capable of obtaining a clear image with no image deletion under high temperature and high humidity without using a drum heater becomes possible.

Continuation of the front page (56) References JP-A-2-101474 (JP, A) JP-A-8-76472 (JP, A) JP-A-8-76504 (JP, A) JP-A-8-76477 (JP) JP-A-5-150539 (JP, A) JP-A-8-137124 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 5/08 105 G03G 9/08 371

Claims (3)

(57) [Claims] An element ratio of a surface layer is determined by a composition formula [a-Si _1-x
C _x : H], X is 0.95 ≦ X <1
Copiers using amorphous silicon photoconductors
Or the printer has a Vickers hardness of the surface layer.
When it is 300 or less, the hardness on the side in contact with the photoconductive layer is large,
Gradually reduce the hardness toward the surface
Volume resistivity of 10 ² to 10 as toner for developing an electrostatic latent image
¹⁰ in the range of [Omega] cm, and 100 particle size in the ratio of the average particle size of the toner: 1 to 2: 0.3 to 5 wt% abrasive cleaning particles in the 1 range, the silica fine powder 0. Amo characterized by containing 3 to 2 % by weight
Copier or pudding using Rufus silicon photoconductor
Ta . 2. The silica fine powder is a hydrophobic silica,
2. A copy using an amorphous silicon photoreceptor according to claim 1, wherein the primary particle diameter is 100 nm or less.
Machine or printer . 3. A copying machine using an amorphous silicon photoreceptor according to claim 1, wherein said silica fine powder is used alone or in combination of two or more kinds.
Is a printer .