JPH0451266A - Image forming device - Google Patents

Abstract

PURPOSE:To simplify a structure, to attain miniaturization, and to stably electrify a latent image carrier by making a conductive member incorporating either of resin or metal or both of them into a thin plate shape and bringing the conductive layer into contact with the latent image carrier in a state where the thickness, Young's modulus, and width of the conductive member satisfy a specific correlation value. CONSTITUTION:When a sensitizing layer 3 is electrified through the use of an electrifying means composed of the conductive member 4 so as to obtain a prescribed potential on its surface, the dimension and material of the member 4 are selected so that the relation of the thickness (t) (mm), Young's modulus E (kg/mm<2>), and width (w) (mm) of the conductive member incorporating either of the resin or metal or both of them, is 10<2=wt<3>E<=2X10<4>. Thus, the material of a low Young's modulus and the ultra-thin material of the degree of 30(mum) are obtained and the member 4 is softly and stably in contact with the latent image carrier 1, and sufficient electrification can be stably carried out. On the other hand, the wear and damage of the latent image carrier 1 are prevented or reduced, and durability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus having a charging means for contacting and charging a latent image carrier.

[Prior Art] As disclosed in USP-2297691, a conventional image forming apparatus forms a potential gradient on a latent image carrier by rubbing the latent image carrier, and exposes the latent image carrier to an image. This is known as the so-called Carlson process, in which an electrostatic latent image is formed, the electrostatic latent image is developed with a developer, the electrostatic latent image is visualized, and the electrostatic latent image is transferred onto recording paper or the like. However, since the electrostatic latent image becomes non-uniform with the above-mentioned charging technique for the latent image carrier, corona charging using a corona discharger as disclosed in USP-2778946 or as disclosed in JP-A-64-7070 The latent image carrier was uniformly charged by roller charging using a conductive roller.

[Problems to be solved by the invention] However, the above-mentioned corona charging technology requires a large number of parts for the corona discharger and its installation, resulting in a complicated structure and high cost, and in the case of negative charging, ozone is generated. There was a problem. Further, the above-mentioned roller charging technology similarly has the problem that the mechanism for pressing the latent image carrier against the charging roller and the rotating mechanism for the charging roller are complicated and require a large number of parts, resulting in high costs.

SUMMARY OF THE INVENTION The present invention is intended to solve these problems, and an object of the present invention is to provide an image forming apparatus having a simple structure and a small-sized charging means. Still another object is to provide an image forming apparatus that can stably charge a latent image carrier and stably form a high-quality image with high coverage.

[Means for Solving the Problems] The image forming apparatus of the present invention has a charging means for bringing a conductive member into contact with the latent image carrier to charge the latent image carrier, and image-wise exposing the latent image carrier to the image forming apparatus. In an image forming apparatus that forms an electrostatic latent image and develops the electrostatic latent image with toner to make it visible, the conductive member has a thin plate shape, and the thickness of the conductive member is t [mm
], Young's modulus E [kg/mm2], and width w [mm] satisfy 102≦wt3E≦2×104, and the electroconductive member is in contact with the latent image carrier at a predetermined position.

Further, the image forming apparatus of the present invention is characterized in that toner remaining on the latent image carrier is removed using a conductive member.

Furthermore, the image forming apparatus of the present invention is characterized in that the conductive member includes one or both of resin and metal.

[Function] According to the above configuration of the present invention, the latent image carrier can be directly charged by the conductive elastic body, the charging means has no moving parts, and the position relative to the latent image carrier can be easily set. It is possible to provide an image forming apparatus having a simple structure, small size and thin charging means.

Furthermore, by keeping the elastic modulus of the conductive member within a predetermined range, it is possible to maintain stable contact with the latent image carrier and prevent durability deterioration of the conductive member and the latent image carrier due to contact. can. Furthermore, by rubbing the latent image carrier with a conductive member, cleaning and charging of the latent image carrier can be performed with the same member, making it possible to provide a small and inexpensive image forming apparatus.

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

[Embodiment 1] FIG. 1 is a cross-sectional schematic diagram of an image forming apparatus according to an embodiment of the present invention, in which a latent image carrier 1 has an organic or inorganic photoconductive material on a conductive support 2. A photosensitive layer 3 is formed, and after the photosensitive layer 3 is charged using a charging means composed of a thin plate-shaped conductive member 4 so that the surface has a predetermined potential, the photosensitive layer 3 is charged with a laser, LED, etc. The light emitted from the light source 5 passes through the imaging optical system 6 and selectively irradiates the photosensitive layer 3 according to the image, thereby obtaining a potential contrast on the photosensitive layer 3 and forming an electrostatic latent image. The latent image carrier 1 on which the electrostatic latent image has been formed is then applied with toner 8 to the image area by the developing device 7 to make the electrostatic latent image visible, and transferred by a corona transfer device, a transfer roller, etc. An image of toner 8 is transferred onto recording paper 10 using device 9, and toner 8 is transferred onto recording paper 1 using heat or pressure.
0 and a desired image is obtained on the recording paper 10.

On the other hand, the toner 8 remaining on the latent image carrier 1 after being transferred is removed by a cleaning device 11, and the toner 8 is again subjected to the process subsequent to charging. When line images, character images, and solid images were continuously formed on 10,000 sheets at a resolution of 300 [DP4] using the image forming apparatus shown in Fig. 1, the line images at 300 [DPI] did not become thick. It was possible to stably form a high-temperature solid image with an OD value of 1.4 or more without trailing or blurring at the edge of the character image. Further, there was almost no surface deterioration of the latent image carrier 1 and the conductive member 4, and high printing quality could be maintained.

Furthermore, the charging means occupies almost no space, making it possible to downsize the image forming apparatus.

In FIG. 1, the latent image carrier 1 can be cylindrical or belt-shaped, and the conductive support 2 is
A conductive metal material such as aluminum can be used, and the photosensitive layer 3 can use an organic or inorganic photosensitive material. The thin plate-shaped conductive member 4 is made of a composite material in which a conductive material such as metal or carbon black is dispersed or coated in a thin metal film such as phosphor bronze, stainless steel, or nickel, or a thin resin plate such as polyimide, polyethylene terephthalate, or polypropylene. A thin plate-like member of the material can be used. Furthermore, the dimensions and material of the conductive member 4 are selected so that the relationship between the conductive member's thickness t [mm], Young's modulus E [kg/mm2], and width w [mm] is 102≦wt3E. By this, even if a material with a low Young's modulus or an ultra-thin material of about 30 [μm] is used, the conductive member 4 can be brought into soft and stable contact with the latent image carrier 1, and the latent image carrier 1 can be sufficiently By selecting the dimensions and material of the conductive member 4 so that charging can be performed stably and satisfying wt3E≦2×104, abrasion and scratches on the latent image carrier 1 can be prevented or reduced. The durability of the carrier 1 can be improved.

Note that the present invention is not limited to the configuration shown in FIG. 1, and the conductive member 4 is connected to a high-voltage power source via a current limiting resistor or the like to stabilize the latent image carrier 1. While charging, the charging potential is kept constant. Further, although the arrows indicate the rotation direction of each member, this does not limit the present invention.

FIG. 2 is a cross-sectional schematic view of the main parts of an image forming apparatus according to another embodiment of the present invention, in which the surface of a resin plate 21 having a low Young's modulus such as chloroprene rubber is coated with a conductive metal thin film 22 such as nickel. to form a conductive member 23, and the latent image carrier 2
The latent image carrier 24 is charged by bringing the ends of the conductive member 23 into contact with each other in the forward direction with respect to the rotation direction of the latent image carrier 24 and applying a predetermined voltage from the high voltage power source 25. With the configuration shown in FIG. 2, the conductive member 23 can be brought into stable contact with the latent image carrier 24 with very low pressure, and the wall thickness is somewhat thick at 2 to 3 mm. Thin plate-shaped conductive member 2
Even if 3 is used, the latent image carrier 24 can be stably charged.

In FIG. 2, the ends of the conductive member 23 are curved to prevent damage caused by contact between the conductive member 23 and the latent image carrier 24, and to prevent damage caused by contact between the conductive member 23 and the latent image carrier 24. It is possible to prevent sticking from occurring due to an excessive friction coefficient between the two. Further, although FIG. 2 shows an example in which the conductive member 23 is brought into contact with the latent image carrier 24 in the forward direction relative to the rotating direction, the latent image carrier 24 will not be charged even if the conductive member 23 is brought into contact with the latent image carrier 24 in the opposite direction. Although this is possible, in the case of abutting in the opposite direction, it is preferable to reduce the contact pressure and form the ends of the conductive member 23 so as not to form sharp corners.

FIG. 3 is a schematic cross-sectional view of a main part of an image forming apparatus according to still another embodiment of the present invention, in which a first conductive member 31 and a second conductive member 32 are brought into contact with a latent image carrier 33. The latent image carrier 33 is charged, and the first conductive member 31 is connected to the ground or a first power source 34 superimposed with alternating current, and the second conductive member 32 includes a current control circuit and the like and is capable of applying high voltage. It is connected to two power sources 35. By adopting the configuration shown in FIG. 3, it is possible to stably bring the conductive member into contact with the latent image carrier 33 with extremely low pressure, and not only can the latent image carrier 33 be stably charged, but also After neutralizing the latent image carrier 33 with the first conductive member 31, the second conductive member 32 charges the latent image carrier 33 to a predetermined potential to maintain a stable charged state. It is possible to prevent fluctuations in image density.

FIG. 4 is a cross-sectional schematic diagram of a main part of an image forming apparatus according to still another embodiment of the present invention, in which a conductive member 41 is formed by dispersing conductive carbon black in urethane rubber,
The end of the conductive member 41 is brought into contact with the latent image carrier 42 and a predetermined voltage is applied by the high-voltage electricity i43 to charge the latent image carrier 42. This removes residues such as toner and paper dust. With the configuration shown in FIG. 4, not only can the latent image carrier 42 be stably charged with the conductive member 41, but also the latent image carrier 42
Toner and the like remaining on the image forming apparatus after transfer can be cleaned, and the image forming apparatus can be made smaller and less expensive.

Although FIG. 4 shows an example in which the conductive member 41 is formed by dispersing a conductive substance in a resin, other methods such as forming a conductive layer on the surface of a resin blade by plating or the like or using a plate spring or the like are also possible. The conductive member 41 can be formed by various methods such as coating a metal thin film with a fluororesin coating, but the present invention is not limited by the forming method. Sex member 41
Although the example in which the latent image carrier 24 is brought into contact with the latent image carrier 42 in the opposite direction to the rotating direction of the latent image carrier 42 has been shown, even if the latent image carrier 24 is brought into contact with the latent image carrier 24 in the forward direction,
Needless to say, it is possible to perform charging and cleaning.

FIG. 5 is a schematic cross-sectional view of a main part of an image forming apparatus according to still another embodiment of the present invention, in which a latent image carrier 5 is formed with a predetermined curvature.
A conductive member 51 made of a metal thin film or the like and a cleaning blade 52 made of a plate-shaped resin such as urethane rubber or silicone rubber are integrally formed in contact with the latent image carrier 53. After cleaning residual toner and the like, a predetermined portion of the conductive member 51 is brought into contact with the latent image carrier 53 to charge the surface of the latent image carrier 53 to a predetermined potential. By adopting the configuration as shown in FIG. 4, the latent image carrier 42 can be stably charged by the conductive member 41, and the image forming apparatus can be made smaller and less expensive.

In FIG. 4, the conductive member 41 can be integrally formed by insert molding into the cutting blade 52, thereby reducing the number of parts and making it possible to further reduce the size and cost. Needless to say, it is possible to reduce the size and price even by integrating the parts.

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 is particularly effective when applied to printers, copiers, facsimile machines, and display devices. be.

[Effects of the Invention] As described above, according to the present invention, the latent image carrier can be stably charged by bringing the conductive member into contact with the latent image carrier at a low pressure to charge the latent image carrier. The present invention not only provides an image forming apparatus that can stably form high-quality images at a high speed, but also provides an image forming apparatus that is simple in structure, small in size, and inexpensive.

In addition, by removing toner remaining on the latent image carrier with a conductive member, charging and cleaning can be performed at the same time, streamlining the electrophotographic process and making the image forming apparatus more compact and inexpensive. It also has the effect of being able to be converted into

Furthermore, by configuring the conductive member to include one or both of resin and metal, it is possible to bring the conductive member into softer contact with the latent image carrier and maintain stable charging over a long period of time, preventing scratches and discharge. It also has the effect that it is possible to provide a small, low-cost image forming apparatus having a highly reliable charging means and preventing deterioration due to the like.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional schematic diagram of an image forming apparatus according to an embodiment of the present invention, FIG. 2 is a cross-sectional schematic diagram of main parts of an image forming apparatus according to another embodiment of the present invention, and FIG. FIG. 4 is a schematic cross-sectional view of a main part of an image forming apparatus according to another embodiment of the present invention. FIG. 5 is a schematic cross-sectional view of a main part of an image forming apparatus according to another embodiment of the present invention. FIG. 2 is a cross-sectional schematic diagram of the main parts of the forming device. 1, 24. 33. 42. 53...Latent image carrier 4, 23. 41. 51...
Conductive member 7 Developing device 8 Toner cleaning device First conductive member Second conductive member and above

Claims (3)

[Claims] (1) It has a charging means that brings a conductive member into contact with the latent image carrier and charges the latent image carrier, and forms an electrostatic latent image by imagewise exposing the latent image carrier, and forms an electrostatic latent image. In an image forming apparatus that develops and visualizes with toner, the conductive member has a thin plate shape, and the thickness of the conductive member is [mm], the Young's modulus E [kg/mm^2], and the width. An image forming apparatus characterized in that w [mm] satisfies 10^2≦wt^3E≦2×10^4 and comes into contact with the latent image carrier at a predetermined position of the conductive member. (2) The image forming apparatus according to claim 1, wherein the toner remaining on the latent image carrier is removed by the conductive member. (3) The image forming apparatus according to claim 1 or 2, wherein the conductive member includes one or both of resin and metal.