JP3491909B2 - Image forming device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for forming an image with toner. 2. Description of the Related Art A conventional image forming apparatus is disclosed in
When the width of the regulating member is smaller than the toner conveyance width on the toner carrier as shown in 7376, the toner conveyance amount on the toner carrier is kept uniform to stabilize the image formation, and the inside of the device due to toner leakage and printing. It was to prevent dirt. However, in the above-described prior art image forming apparatus, a rough surface portion is formed on a toner carrier to form a toner conveying width, and the width of the regulating member is made smaller than the toner conveying width. are doing. The rough surface portion on the toner carrier is
The problem is that since the toner transport ability is higher than that of the non-rough surface, toner leaks from the end of the regulating member, causing in-machine contamination and printing stains, deteriorating image quality and preventing high-resolution image formation. There was a point. Further, if toner leaks, the amount of toner consumption increases, and more space is required for storing the toner in the image forming apparatus, which makes it difficult to reduce the size of the image forming apparatus. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and it is intended to prevent an inside contamination and a print stain due to toner leakage while securing a sufficient amount of toner necessary for image formation on a toner carrier. It is an object of the present invention to provide an image forming apparatus capable of obtaining a high-resolution image. According to the present invention, an electrostatic latent image on a latent image carrier is visualized by toner conveyed by a developing device, and the obtained toner image is recorded on a recording medium by a transfer device. In the transfer image forming apparatus, the developing device is provided with a toner carrier that carries and conveys the toner, and is pressed against the toner carrier to an outside of an image forming width to supply the toner to the toner carrier. A supply member, and a regulating member that is disposed by pressing the toner carrier to the outside of the image forming width to regulate the amount of the toner on the toner carrier supplied by the supply member. Including both ends of the supply member and the regulation member, the supply member and the regulation member are disposed on the toner carrier so as to prevent the toner from leaking at a predetermined width and a predetermined thickness between the supply member and the regulation member. Tona And a leakage preventing member, as the toner leakage preventing member, characterized by using a 5-fold smaller thickness of the film deposition average particle diameter of the toner. According to the above configuration of the present invention, both ends of the supply member and the regulating member overlap with the toner leakage preventing member on the toner carrier, and the toner leakage preventing member is held by the toner carrying member. Since it is arranged to be pressed against the body, it is possible to prevent toner from leaking from both sides of the supply member and the regulating member. Moreover, the widths of the supply member and the regulating member are larger than the inside of the toner leakage prevention member which is the image forming width, and the amount of toner supplied to the image forming width and the charge amount can be kept constant, and a uniform image can be obtained. can get. Further, both ends of the regulating member overlap with the toner leakage preventing member on the toner carrier, and the toner leakage preventing member is disposed so that the regulating member presses the toner carrier, so that both ends of the regulating member can be moved from the both ends of the regulating member. Toner leakage is prevented.
If there is a gap of about 100 μm, the toner leaks from the gap. However, the gap can be eliminated by pressing the toner leakage prevention member against the toner carrier. Further, by using a film having a thickness of not more than five times the toner volume average particle diameter as the toner leakage preventing member, the amount of toner transported on the toner carrier can be regulated to a desired thin layer. An image having a resolution can be formed. If the film used as the toner leakage prevention member is larger than five times the volume average particle diameter of the toner, the toner cannot be regulated in a thin layer, the transport amount increases, and the pressure contact development advantageous for high resolution cannot be performed. FIG. 1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment of the present invention. In the present embodiment, the latent image carrier 1 is formed by forming a photoconductive photosensitive layer 3 on a conductive support portion 2, and the photosensitive layer 3 is charged with a charger 4 such as a corona charger or a charging roller. After being charged using a light source 5 such as a laser or an LED, the photosensitive layer 3 is selectively irradiated with light from a light source 5 such as a laser or an LED according to an image through an imaging optical system 6 to obtain a potential contrast. To form an electrostatic latent image. On the other hand, the developing device 21 is for transporting and developing the toner 8, and the toner carrier 9 for transporting the toner 8 is provided on the outer periphery of the shaft 10.
Are provided concentrically, and a supply member 17 for supplying the toner 8 to the toner carrier 9 is a member in which a foam 19 is concentrically disposed on the outer periphery of a shaft 18. Is pressed against the toner carrier 9, rotates at the same rotational speed as the toner carrier, and charges the toner by pressing and rubbing against the toner carrier 9, so that the toner is directly held on the toner carrier, and becomes nonmagnetic or magnetic. The toner carrier 9 is rotated in a state where the toner carrier 9 is regulated to an appropriate amount by the plate-shaped regulating member 22 made of metal or resin, and the thin layer
Is transported. Note that the seal member 20 is for preventing toner from leaking from the developing unit 21. The toner carrier 9 made of a specific elastic material is pressed against the surface of the photosensitive layer 3 of the latent image carrier 1 at a predetermined pressure, and the toner 8 on the toner carrier 9 is conveyed to the pressure contact portion. Then, the toner 8 charged in accordance with the potential contrast of the latent image carrier 1 and the developing electric field by the developing bias applying means 14 adheres to the photosensitive layer 3, whereby the electrostatic latent image is visualized. Further, an image formed by the toner is transferred onto the recording paper 16 by using a transfer device 15 such as a corona transfer device or a transfer roller, and the transfer toner is fixed on the recording paper by heat or pressure to form a desired image on the recording paper. Can be. The elastic layer 11 and the supply member 17 are made of a soft foam material such as polyurethane foam, polystyrene foam, polyethylene foam, elastomer foam, rubber foam, natural rubber, silicone rubber, urethane rubber, butadiene rubber, chloroprene rubber. And rubbers such as neoprene rubber and NBR, and elastomers containing styrene resin, vinyl chloride resin, polyurethane resin, polyethylene resin, methacrylic resin and the like. Further, as the regulating member 22, a thin leaf spring having a thickness of about several hundred μm using a metal such as stainless steel or phosphor bronze, or a thin resin such as rubber or elastomer can be used. The above is the outline of the image forming apparatus.
An image forming apparatus as shown in FIG. 1 in which a toner carrier 9, a supply member 17, a regulating member, and a toner leakage prevention member 31 having a length relationship in the rotation axis direction of the toner carrier as shown in FIG. An image was formed. A good image could be formed without causing in-machine contamination or print stain due to toner leakage. Further, when a line image, a character image and a solid image were continuously formed over 10,000 sheets,
The line image is formed stably without thickening, there is no tailing of the character image (toner scattering at the rear end) and no background fog (toner adhesion to non-image area), and OD value is 1.5 or more , A solid image having a high density was stably formed. (Comparative Example 1) When an image was formed using an image forming apparatus as shown in FIG. 1 using a supply member having a width of the supply member larger than the width of the toner carrier, an end portion of the toner carrier was obtained. , Causing toner leakage, causing printing stains and in-machine contamination. (Embodiment 2) An image is formed by an image forming apparatus as shown in FIG. 1 in which the toner leakage preventing member 31 is arranged to be pressed against the toner carrier by the regulating member 22 as shown in FIG. . A good image could be formed without causing in-machine contamination or print stain due to toner leakage. Further, when a line image, a character image and a solid image were continuously formed over 10,000 sheets,
When a line image is formed stably without line thickening and a character image is continuously formed, the line image is formed stably without line thickening, and the trailing edge of the character image (toner scattering at the rear end) No high-density solid image having an OD value of 1.5 or more could be formed stably without image fogging or background fogging (adhesion of toner to non-image areas). (Embodiment 3) An image forming apparatus as shown in FIG. 1 using a film having a thickness of 40 μm as a toner leakage preventing member 31 was prepared by using a toner having a volume average particle diameter of 10 μm.
An image was formed. A good image could be formed without causing in-machine contamination or print stain due to toner leakage. Further, when a line image, a character image and a solid image were continuously formed over 10,000 sheets,
When a line image is formed stably without line thickening and a character image is continuously formed, the line image is formed stably without line thickening, and the trailing edge of the character image (toner scattering at the rear end) No high-density solid image having an OD value of 1.5 or more could be formed stably without image fogging or background fogging (adhesion of toner to non-image areas). As described above, the toner carrier that carries the toner on the surface and conveys the toner to the developing area, the supply member that supplies the toner to the toner carrier, and the amount of toner on the toner carrier And a toner leakage preventing member for preventing toner from leaking from the developing device. The image forming width in the rotation axis direction of the toner carrier is P, the toner carrier width is D, and the supply member width is S, when the width of the regulating member is B and the width of the toner leakage preventing member is C, P ≦ S ≦ D, P ≦ B, and S ≦ B + C, so that toner leakage from the regulating member and the end of the toner carrier is prevented. This has the effect that high-resolution images can be formed without causing in-machine contamination or printing stains due to toner. Further, by arranging the toner leakage preventing member on both sides of the regulating member so that the toner leakage preventing member is pressed on the toner carrier, toner leakage from the regulating member and the end portion of the toner carrier is prevented, and the inside of the apparatus due to toner is prevented. This has the effect that a high-resolution image can be formed without causing print stains. Further, by using a film having a thickness smaller than 5 times the volume average particle diameter of the toner to be used as the toner leakage preventing member, toner leakage from the regulating member and the end of the toner carrier is prevented, and There is an effect that a high-resolution image can be formed without causing in-machine contamination and printing stains.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a length relationship of components of the image forming apparatus according to the embodiment of the present invention. FIG. 3 is a view showing a state in which a toner leakage prevention member of the present invention is provided. DESCRIPTION OF SYMBOLS 1 Latent image carrier 2 Conductive support 3 Photosensitive layer 4 Charger 5 Light source 6 Imaging optical system 8 Toner 9 Toner carrier 10 Shaft I 11 Elastic layer 14 Developing bias applying means 15 Transfer device 16 Recording paper 17 Supply member 18 Shaft II 19 Foam 21 Developing device 22 Regulatory member 31 Toner leakage prevention member

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Takehiko Okamura               Seiko, 3-3-5 Yamato, Suwa City, Nagano Prefecture               ー Epson Corporation

Claims (1)

(57) [Claim 1] An electrostatic latent image on a latent image carrier is visualized by toner conveyed by a developing device, and the obtained toner image is transferred to a recording medium by a transfer device. In the image forming apparatus, the developing device includes a toner carrier that carries and conveys the toner, and is disposed in pressure contact with the toner carrier to an outside of an image forming width to supply the toner to the toner carrier. A regulating member arranged to press the toner carrier to the outside of the image forming width to regulate the amount of the toner on the toner carrier supplied by the supplying member; Toner that includes both ends of a supply member and a regulation member, is disposed on the toner carrier, and is disposed between the supply member and the regulation member to prevent leakage of toner with a predetermined width and a predetermined thickness. Leak prevention member An image forming apparatus, wherein a film having a thickness smaller than 5 times the average particle diameter of the toner is used as the toner leakage preventing member.