JP2001194899A - Developing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably form an image of high density that image failure is small by facilitating safely and rapidly electrifying to a desired electrified quantity by making toner a uniform thin layer. SOLUTION: Relating to the device, the toner 8 that is non magnetic and has a spherical shape is utilized, in order to electrify the toner 8 by rolling action while being rolled and slid between a toner carrier 9 and an elastic blade 13 so that it is made into an extremely thin layer and having the toner 8 electrified by rolling action being rolled in a direction opposite to the rotating direction of the toner carrier 9 while in contact with the toner carrier 9 and the elastic blade 13, the toner carrier 9 and the elastic blade 13 are constituted so that one is easily slid on and the other is not easily slid on and also provided with different surface roughness. In this case, the elastic blade 13 is pressed to the toner carrier 9, the electrified toner 8 that is made into the extremely thin layer is retained on the toner carrier 9 and the toner is developed to the latent image carrier 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing method for thinning toner on a toner carrier with an elastic blade and developing the toner on the toner carrier on a latent image carrier.

[0002]

2. Description of the Related Art A conventional developing method is disclosed in JP-A-55-118.
As disclosed in Japanese Unexamined Patent Publication No. 052, a spherical toner is used in the non-contact developing method in order to improve the flying property of the toner. Further, the pressure contact developing method is described in JP-A-57-114163 and JP-A-63-114163.
As disclosed in Japanese Patent Publication No. 226676, a method has been proposed which enables development of a one-component non-magnetic toner.

[0003]

However, the non-contact developing method of the prior art described above is a non-contact developing method.
The distance (gap) between the latent image carrier and the developing electrode was large and it was difficult to form a high-resolution image. Further, in the above-mentioned conventional technology, although the developing electrode effect can be obtained, the development density fluctuates due to insufficient charging of the toner, and the latent image carrier is Top fog (toner attached to non-image area)
Many toners were unnecessarily discarded due to occurrence of the toner.

The present invention makes it possible to easily and stably rapidly charge a toner to a desired charge amount by thinning the toner uniformly.
It is intended to stably form a high-density image with few image defects.

[0005]

A developing method according to the present invention is directed to a developing method for developing a toner on a toner carrier by forming an ultrathin layer on a toner carrier by an elastic blade and developing the toner on the toner carrier on a latent image carrier. A non-magnetic, spherical toner is used as the toner, and the toner carrier and the elastic member are electrically thinned between the toner carrier and the elastic blade so as to be charged by rolling while sliding. The blade is configured such that the toner is slippery on the one hand and harder on the other hand and has a different surface roughness, and the elastic blade is pressed on the toner carrier to form the ultra-thin layer on the toner carrier. Holding the charged toner,
The toner is developed on the latent image carrier.

In a developing method of thinning a toner on a toner carrier with an elastic blade and developing the toner on the toner carrier on a latent image carrier, a non-magnetic spherical toner is used as the toner. The toner carrier and the elastic blade are contacted with the toner carrier and the elastic blade so that the toner carrier and the elastic blade are charged by sliding rolling while rolling in a direction opposite to the rotation direction of the toner carrier. On the one hand, it is slippery, on the other hand, it is hard to slip, and it is configured with different surface roughness, the elastic blade is pressed on the toner carrier, and the thinned and charged toner is deposited on the toner carrier. Holding the toner and developing the toner on the latent image carrier.

[0007]

According to the above construction of the present invention, a non-magnetic spherical toner is used, and the toner is formed into an extremely thin layer between the toner carrier and the elastic blade, and is charged by rolling while rolling. The toner carrier and the elastic blade so that the toner is charged by rolling while sliding in a direction opposite to the rotation direction of the toner carrier in contact with the toner carrier and the elastic blade. The toner is made slippery on the one hand and hard to slip on the other hand, and has a different surface roughness, holds the thinned and charged toner on the toner carrier, and transfers the toner to the latent image carrier. By developing, the toner on the toner carrier is formed into an ultra-thin layer by an elastic blade, so that stable toner charging is possible, image density fluctuation is small, and a developing method excellent in durability is provided. It can be provided.

Further, the toner carrier and the elastic blade are configured such that the toner is slippery on the one hand and hard to slip on the other, and the surface roughness of the elastic blade and the surface roughness of the toner carrier are different from each other. Thus, the toner can be more stably charged to a desired charge amount and rapidly charged to a predetermined charge amount, and a high-density image can be formed stably. Accordingly, background fog on the latent image carrier can be reduced and unnecessary waste toner can be reduced, and image defects such as background fog are reduced, high contrast, high resolution, and high density images are economically reduced in running. A development method that can be formed at a low cost can be provided.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to examples. FIG. 1 is a schematic cross-sectional view of an image forming apparatus using the developing method of the present invention, in which a latent image carrier 1 has a photosensitive layer 3 having organic or inorganic photoconductivity on a conductive support 2. After the photosensitive layer 3 is charged using a charger 4 such as a corona charger or a charging roller, light emitted from a light source 5 such as a laser or an LED is passed through an imaging optical system 6 to form a photosensitive layer. 3 is selectively irradiated with light in accordance with an image to obtain a potential contrast to form an electrostatic latent image.

On the other hand, the developing device 7 transports and develops the non-magnetic spherical toner 8, and the toner carrier 9 which transports the toner 8 has an elastic layer 11
And the conductive layer 12 are arranged concentrically, respectively.
A plate-like elastic blade 13 made of a non-magnetic or magnetic metal or resin is pressed against the toner carrier 9 to charge the toner 8 to a predetermined polarity and to thin the toner layer to an appropriate amount. The non-magnetic toner 8 is directly held on the toner carrier 9 near the surface by an electrostatic image force, and the toner carrier 9 is rotated to convey the thin layer toner 8.

When the toner 8 is conveyed to the developing gap where the latent image carrier 1 and the toner carrier 9 are close to each other, a developing electric field is formed by the potential contrast of the latent image carrier 1 and the developing bias applying means 14, and the developing electric field is generated. As a result, the toner 8 charged in accordance with the image is adhered to the latent image carrier 1 and the electrostatic latent image is visualized. Further, a transfer device 1 such as a corona transfer device or a transfer roller
5, the toner image is transferred onto the recording paper 16 and the toner is fixed to the recording paper using heat and pressure to obtain a desired image on the recording paper.

When a 600 [DPI] line image, a character image, and a solid image are continuously formed over 10,000 sheets using an image forming apparatus as shown in FIG. 1, the 600 [DPI] line image becomes thicker. A solid image having a high density with an OD value of 1.4 or more can be formed stably without tailing or background fogging at the end of the image. Of course, there was little ground fog on the latent image carrier 1 and the amount of waste toner could be reduced. Further, the latent image carrier 1
No fixation or fusion state of the toner was observed on the upper surface or on the toner carrier 9, and it was confirmed that the durability was improved by the spherical toner.

FIG. 2 is a schematic cross-sectional view of an image forming apparatus using a developing method in another embodiment of the present invention. Members having substantially the same functions and the same names as those in FIG. Omitted. The developing device 21 conveys and develops the magnetic spherical toner 8, and the toner carrier 9 that conveys the toner 8 transfers the magnetic toner 8 by the leakage magnetic flux around the outer periphery of the magnetic field generation layer 22. 9 is pressed directly onto the toner carrier 9 by pressing a thin-plate spring-like elastic blade 13 made of non-magnetic or magnetic metal or resin onto the toner carrier 9 to charge the toner 8 to a predetermined polarity and to form an appropriate thin layer. Then, the toner carrier 9 is rotated to convey the thin layer toner 8.

The toner carrier 9 is pressed against the latent image carrier 1 at a predetermined pressure, and when the toner 8 on the toner carrier 9 is transported to the pressure contact portion, the potential contrast of the latent image carrier 1 and the development The toner 8 charged in accordance with the developing electric field by the bias applying means 14 adheres to the latent image carrier 1, and the electrostatic latent image is visualized.

When an image forming apparatus as shown in FIG. 2 is used to continuously form 600 [DPI] line images, character images and solid images over 10,000 sheets, the 600 [DPI] line images become thicker. It is possible to stably form a high-density solid image with an OD value of 1.4 or more without forming a line pair image with the highest resolution and without tailing or ground fogging at the image end. In addition, there was no ground fog on the recording paper, and of course, there was no ground fog on the latent image carrier, and the amount of waste toner was greatly reduced. Further, no fixation or fusion state of the toner on the latent image carrier 1 or the toner carrier 9 was observed, and it was confirmed that the durability was improved by the spherical toner.

FIG. 3 is a schematic cross-sectional view of a toner usable in the developing method of the present invention, showing an example of a magnetic toner produced by a pulverizing method. The toner 31 uses a polyester resin or a styrene acrylic resin as a binder 32, a magnetic powder 33 such as ferrite, a colorant 34 such as carbon black, a low molecular weight wax (not shown) such as polypropylene, and other components. An additive is dispersed, kneaded, pulverized, classified and finely divided to about 10 [μm], and an external additive 35 such as silicon dioxide or titanium dioxide is externally added. The inside is subjected to a spheroidization process, and the relationship between the long axis length b and the single axis length a of a rectangle circumscribing an arbitrary cross section is a ≦ b ≦ 1.5 × a. However, examples of the sphering treatment method include a spray drying method, a mechanochemical method, and a polymerization method.

As the toner usable in the developing method of the present invention, not only a magnetic toner but also a non-magnetic toner can be used, and any of a resin-based toner and a wax-based toner may be used. The method may be not only a pulverization method but also a polymerization method.

FIG. 4 is a schematic view of an elastic blade pressing portion according to still another embodiment of the present invention.
Is pressed against the toner carrier 43 via the spherical toner 42, and the elastic blade 41 and the toner carrier 43
May be surface-treated in accordance with the charging polarity of the toner 42. The toner carrier 43 is rotated in the direction of arrow 44 to convey the toner 42. However, the surface roughness of the elastic blade 41 is made larger than the surface roughness of the toner carrier 43 so that the toner 42 is The toner 42 rolls in the direction of arrow 45 by making it slippery on the upper side and harder on the elastic blade 41. Therefore, the toner 42
The time required for the toner to pass through the pressure contact portion and the chance of contact with the frictional charging member are increased, the toner can be rapidly and stably charged to a stable charge amount, and a high-density image can be stably formed.

1 and 2, the elastic layer 11 is made of natural rubber, silicon rubber, urethane rubber, butadiene rubber,
Using chloroprene rubber, neoprene rubber, NBR, etc.
As the form of the elastic layer, rubber, foam, sponge or the like, or used, styrene resin, vinyl chloride resin,
An elastomer containing a polyurethane resin, a polyethylene resin, a methacrylic resin, or the like can be used. The magnetic field generating layer 22 can be made of a known material as a magnetic recording material or a magnet material. More specifically, Fe, Ni,
A magnetic material containing at least one element of Co, Mn, and Cr, for example, γ-Fe ₂ O ₃ , Ba-Fe,
Ni-Co, Co-Cr, Mn-Al, etc. can be used,
The film thickness is reduced to 100 [μm] or less, preferably around 10 [μm], to ensure flexibility and to enable pressure welding development, and to minimize the minimum magnetization reversal pitch to make the toner uniform and thin. Variations in the amount of toner conveyed on the developing roller due to the formation of the magnetic brush can be suppressed to a minute pitch, and density unevenness can be reduced. Furthermore, regarding the layer configuration,
An intermediate layer that facilitates bonding between layers and a protective layer that protects the surface may be provided.

In FIGS. 1 to 4, the present invention is not limited only by the configuration shown in the drawings. Arrows indicate the rotation directions of the respective members, but do not limit the present invention. Furthermore, the developing method can be used regardless of whether it is regular development or reversal development, and the charge polarity of the toner is not limited to positive or negative.

Although the embodiments have been described above, the present invention can be applied not only to the above embodiments but also to a wide range of developing apparatuses such as electrophotography. Particularly, the present invention is effective when applied to printers, copiers, facsimile machines and displays. It is.

[0022]

As described above, according to the present invention, a non-magnetic, spherical toner is used, and the toner is formed into an extremely thin layer between the toner carrier and the elastic blade, and is charged by rolling while rolling. So that the toner slides on the toner carrier and the elastic blade so that the toner is in contact with the toner carrier and the elastic blade and rolls while rolling in the direction opposite to the rotation direction of the toner carrier. Easy, on the other hand hard to slip, and configured with different surface roughness, pressing the elastic blade on the toner carrier,
By holding the charged toner in an ultra-thin layer on the toner carrier, and developing the toner on the latent image carrier, the toner is ultra-thin-layered on the toner carrier by an elastic blade,
It is possible to provide a developing method which is stable in toner charging, has little image density fluctuation, and has excellent durability.

Further, by making the toner carrier and the elastic blade so that the toner is slippery on the one hand and harder to slip on the other, and the surface roughness of the elastic blade and the surface roughness of the toner carrier are different from each other, Thus, the toner can be more stably charged to a desired charge amount and rapidly charged to a predetermined charge amount, and a high-density image can be formed stably.

Therefore, according to the present invention, background fogging on the latent image carrier can be reduced and unnecessary waste toner can be reduced, and there are few image defects such as background fog, high contrast, high resolution and high resolution. This is an excellent effect that a developing method capable of economically forming an image having a low density at a low running cost can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an image forming apparatus using a developing method of the present invention.

FIG. 2 is a schematic cross-sectional view of an image forming apparatus using a developing method according to another embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view of a toner that can be used in the developing method of the present invention.

FIG. 4 is a schematic view of an elastic blade press-contact portion according to still another embodiment of the present invention.

[Explanation of symbols]

1: latent image carrier, 7, 21: developing device, 8, 31, 42
... toner, 9, 43 ... toner carrier, 11 ... elastic layer, 1
2: conductive layer, 13, 41: elastic blade, 22: magnetic field generating layer

Claims (2)

[Claims] 1. A developing method for thinning a toner on a toner carrier using an elastic blade and developing the toner on the toner carrier on a latent image carrier, wherein a non-magnetic spherical toner is used as the toner. Using, the toner carrier and the elastic blade so that the toner is slippery on the one hand, so that the toner is charged to an extremely thin layer between the toner carrier and the elastic blade by rolling while sliding. On the other hand, it is hard to slip, and is configured with different surface roughness, presses the elastic blade on the toner carrier, holds the ultrathin layered and charged toner on the toner carrier, Is developed on the latent image carrier. 2. A developing method for thinning a toner on a toner carrier by an elastic blade and developing the toner on the toner carrier on a latent image carrier, wherein a non-magnetic spherical toner is used as the toner. The toner carrier and the elastic blade are contacted with the toner carrier and the elastic blade so that the toner carrier and the elastic blade are electrically charged by rolling while sliding in a direction opposite to the rotation direction of the toner carrier. On the one hand, it is slippery, on the other hand, it is hard to slip, and it is configured with different surface roughness, and the elastic blade is pressed on the toner carrier, and the thinned and charged toner is placed on the toner carrier. Holding the toner and developing the toner on the latent image carrier.