JPH04118680A - Image forming device - Google Patents

Abstract

PURPOSE:To form a high-resolution image by using magnetic toner as toner and providing a magnetic field generation layer on a toner carrier. CONSTITUTION:When a latent image carrier 1 approximates the toner carrier 9, the magnetic toner 8 is carried to a developing gap part and a developing electric field is formed by the potential contrast of the carrier 1 and by the use of a developing bias impressing means 14, the electrostatically charged toner 8 adheres to the carrier 1 to develop an electrostatic latent image. In the non-image part of the carrier 1, the toner 8 on the carrier 9 is electrostatically charged to be in a specified polarity by an elastic blade 13, the electric field is formed by the means 14 in a direction where development is prevented, and the toner 8 is restricted to the carrier 9 with specified magnetic force by the magnetic field generation layer 12, so that surface fogging on the carrier 1 by the toner 8 is hardly caused. The residual toner on the carrier 1 is made in a state where it uniformly and easily contacts with the carrier 9 by a uniformizing brush 17, thereby easily performing the cleaning to remove the residual toner with the magnetic force. Thus, the high resolution image is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus that simultaneously performs a developing process and a cleaning process.

[Prior Art] A conventional image forming apparatus is a "cleanerless laser printer J ("Japan H
ardcopy'90" collection of papers p189-p192)
As shown in , the non-magnetic toner of the negative component is developed under pressure, and the developing bias voltage is set in a range where the potential of the toner remaining on the latent image carrier is less affected. The image was developed while cleaning the remaining toner on the image.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technology, toner of different polarity causes smearing (a state in which toner adheres to non-image areas) on the latent image carrier, and the uniforming brush removes the toner after transfer. I had to level out the residual toner. In addition, if there is too much ground force blur on the latent image carrier or if it is not sufficiently uniformed, ground force blur may also occur on the recording paper, or an afterimage may occur due to the history of image formation, resulting in a significant decrease in image quality. It was.

SUMMARY OF THE INVENTION The present invention is intended to solve these problems, and its purpose is to provide a linarless image forming apparatus that is highly reliable and capable of forming high-quality images. Still another object is to provide an image forming apparatus capable of reducing ground force blur on a latent image carrier. Still another object is to provide a developing method suitable for developing magnetic toner with high resolution. Still another object is to provide an image forming apparatus that is small, inexpensive, and does not require maintenance and inspection work without a cleaner device.

[Means for Solving the Problems] An image forming apparatus of the present invention is an image forming apparatus that simultaneously performs a developing process and a cleaning process on a latent image carrier, in which the toner is a magnetic toner, and the toner is transported. The toner carrier for development has a magnetic field generating layer.

Further, the image forming apparatus of the present invention is characterized in that the toner is made into a thin layer by an elastic blade.

Further, the image forming apparatus of the present invention is characterized in that the toner is developed on the latent image carrier while the toner carrier is in pressure contact with the latent image carrier through the toner.

[Function] According to the above configuration of the present invention, by using a magnetic toner and having a structure in which the toner carrier has a magnetic field generating layer, the toner is restrained to the toner carrier by magnetic force and the latent image is retained. It is possible to reduce ground force blur on the body, and it is possible to form high-contrast, high-resolution images even with a cleanerless image forming apparatus. Further, even if residual toner is generated on the latent image carrier due to transfer residue, etc., the residual toner on the latent image carrier can be cleaned by applying not only Coulomb force but also magnetic force at the same time as the developing process.

Further, according to the above configuration of the present invention, by thinning the toner with the elastic blade, the toner can be stably abraded.
It is possible to apply triboelectric charging to align the toner with a predetermined charging polarity, reduce ground force blur on the latent image carrier due to toner of different polarity, and reduce toner that is unnecessarily developed and remains on the latent image carrier.

Furthermore, by using pressure-contact development, it is possible to bring the development electrode closest to the latent image carrier and form a high-resolution image. In addition, it is possible to form a sufficiently large development-blocking electric field in the non-image area during development, thereby reducing ground force blur, and toner carrying residual toner of different polarity adhering to the non-image area by magnetic force and Coulomb force. The remaining toner can be cleaned by suctioning it to the side of the body.

Hereinafter, the present invention will be explained in detail with reference to Examples.

[Example] FIG. 1 is a cross-sectional schematic diagram of an image forming apparatus in an example of the present invention, in which a latent image carrier 1 has an organic or inorganic photoconductive material on a conductive support part 2. A photosensitive layer 3 is formed, and after the photosensitive layer 3 is charged using a charger 4 such as a corona charger or a charging roller, it is charged with a laser or LE.
Light emitted from a light source 5 such as D or LC3 is selectively irradiated onto the photosensitive layer 3 according to the image through an imaging optical system 6 to obtain a potential contrast and form an electrostatic latent image. On the other hand, the developing device 7
The magnetic toner 8 is transported and developed, and the toner carrier 9 that transports the magnetic toner 8 has an elastic layer 11 and a magnetic field generating layer 12 arranged concentrically around the outer periphery of a shaft 10. , holding the magnetic toner 8 directly on the toner carrier 9 by leakage magnetic flux around the outer periphery of the magnetic field generating layer 12;
A thin plate spring-like elastic blade 13 made of non-magnetic or magnetic metal or resin is pressed against the toner carrier 9 to charge the magnetic toner 8 to a predetermined polarity and thin the toner to an appropriate amount. The thin layer of magnetic toner 8 is conveyed by rotating the toner. When the magnetic toner 8 is conveyed to the development 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 a developing electric field is formed according to the developing electric field. The charged toner 8 adheres to the latent image carrier 1, and the electrostatic latent image is visualized. On the other hand, in the non-image area of the latent image carrier 1, the magnetic toner 8 on the toner carrier 9 is moved by the elastic blade 13.
is charged to a predetermined polarity, an electric field is formed in a direction to prevent development by the developing bias applying means, and the magnetic toner 8 is restrained to the toner carrier 9 by a predetermined magnetic force by the magnetic field generating layer 12. Due to this, ground force blurring on the latent image carrier 1 due to the magnetic toner 8 hardly occurs.

The magnetic toner 8 developed on the latent image carrier 1 is transferred to a recording paper 16 using a transfer device 15 such as a corona transfer device or a transfer roller.
The toner is transferred onto the recording paper and fixed to the recording paper using heat or pressure to obtain a desired image on the recording paper. Furthermore, since a small amount of magnetic toner 8 remains on the latent image carrier 1 after transfer due to untransferred material, the surface is smoothed by the equalizing brush 17, and the electric charge on the surface of the latent image carrier 1 is removed by the static elimination lamp 18. Remove the static charge and repeat the process below. Incidentally, since the residual toner on the latent image carrier 1 is leveled by the equalizing brush 17, static elimination and charging can be performed almost uniformly.
Next, it is in a state where it is easy to come into uniform contact with the toner carrier 9, and residual toner can be easily cleaned using magnetic force. When we continuously formed 10,000 sheets of 300 [DPI] line images, character images, and solid images using the image forming apparatus shown in Figure 1, the 300 [DPI] line images did not become thick. It is possible to stably form a high-temperature solid image with an OD value of 1°4 or more, without trailing at the edge of the image, with no force blur, afterimage, or toner scattering, and with the recording paper 16.
Not only was there no ground force blur on the latent image carrier 1, but also ground force blur could be reduced on the latent image carrier 1. Furthermore, by making the magnetic toner 8 spherical, residual toner can be removed more easily and image quality can be improved, and since there is almost no filming due to the fusion and solidification of the toner, the latent image carrier 1 and the toner It was confirmed that the durability of the carrier 9, the elastic blade 13, etc. was improved.

In FIG. 1, the elastic layer 11 is made of natural rubber, silicone rubber, urethane rubber, butadiene rubber, chloroprene rubber, neoprene rubber, NBR, etc., and the form of the elastic layer is rubber, foam, sponge, etc. Alternatively, stable pressure development is possible by using an elastomer containing styrene resin, vinyl chloride resin, polyurethane resin, polyethylene resin, methacrylic resin, or the like.

Further, the magnetic field generation layer 12 can be made of a known magnetic recording material or magnet material, and more specifically, Fe
, Ni, Co, Mn, Cr, a magnetic material containing at least one kind of element, for example,
y-Fe203, Ba-Fe, Ni-Co.

Co-Cr, Mn-Al, etc. can be used, and the film thickness is 100 mm.
[μm] or less, preferably around 10 [μm3] to ensure flexibility and enable pressure contact development, and at the same time make the minimum magnetization reversal pitch minute to make the toner a uniformly thin layer, and at the same time develop by forming a magnetic brush. It is possible to suppress fluctuations in the amount of toner conveyed on the roller and reduce temperature unevenness.

However, regarding the layer structure on the surface of the toner carrier 9, an intermediate layer that facilitates bonding between layers or a protective layer that protects the surface may be provided.Furthermore, the magnetic toner 8 that can be used in the present invention is a resin-based Toner: Any wax-based toner is fine.
Toner manufacturing methods include not only pulverization methods but also magnetic toners manufactured by polymerization methods, but in particular, spherical toner is used and the toner is transferred on an elastic blade or toner carrier to reduce the friction of the toner. By increasing charging opportunities,
The charge polarity of the toner can be made uniform and a sufficient amount of charge can be obtained. Furthermore, as for the equalizing brush 17, it is possible to use a base with fur brushes implanted therein, metal fibers implanted therein, a blade in the shape of a thin plate spring, or the like. Furthermore, regarding the static elimination lamp 18,
Although a light source that emits light at a wavelength to which the latent image carrier 1 has photosensitivity can be used, it is also possible to omit the light source.

In addition, in FIG. 1, the present invention is not limited only to the configuration shown in the figure. Further, although the arrows indicate the rotation direction of each member, this does not limit the present invention. Furthermore, the developing method can be used regardless of whether it is regular development or reverse development, and the charging 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 image forming apparatuses that use electrophotography, and especially when applied to printers, copiers, facsimiles, and displays. It is valid.

[Effects of the Invention] As described above, according to the present invention, using magnetic toner,
In addition, by configuring the toner carrier to have a magnetic field generation layer, it is possible to reduce ground force blur on the latent image carrier, and even a cleanerless image forming apparatus can form a high-contrast, high-resolution image. be able to. In addition, since residual toner is cleaned at the same time as development using mainly magnetic force and Coulomb force, uncharged toner can also be removed, and images with less ground blur and no afterimages can be formed even with cleanerless image forming apparatuses. In addition, by thinning the toner layer using an elastic blade, it is possible to reduce ground force blur on the latent image carrier, and reduce toner that is unnecessarily developed and remains on the latent image carrier after transfer. .

Furthermore, by using pressure-contact development, it is possible to reduce ground force blur on the latent image carrier and perform sufficient cleaning (at the same time as development), making it possible to stably form high-resolution images. be able to.

Therefore, according to the present invention, it is possible to provide a linarless image forming apparatus that is capable of forming high-resolution, high-temperature images with few image defects such as ground blur and afterimages, and furthermore,
This has the excellent effect of providing a small, low-cost image forming apparatus with no waste toner and low running costs.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional schematic diagram of an image forming apparatus according to an embodiment of the present invention. Latent image carrier developing device Magnetic toner Toner carrier elastic layer Magnetic field generating layer Elastic blade Developing bias applying means More than 8 applicants Seiko Epson Corporation

Claims (3)

[Claims] (1) In an image forming apparatus that simultaneously performs a developing process and a cleaning process on a latent image carrier, the toner is a magnetic toner, and the toner carrier that conveys and develops the toner has a magnetic field generating layer. Features of the image forming device. (2) The image forming apparatus according to claim 1, wherein the toner is made into a thin layer by an elastic blade. (3) The image according to claim 1 or 2, wherein the toner is developed on the latent image carrier while the toner carrier is in pressure contact with the latent image carrier through the toner. Forming device.