JPH1083118A - One-component developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent toner filming on a developing roll and a toner regulating blade and to prolong life by using the toner regulating blade provided with level differences in several parts of its surface. SOLUTION: Toner 3 sent to a supply roll 6 is rubbed onto a developing roll 5 by the supply roll 6, so that a toner layer is formed on the surface of the developing roll 5. The toner layer formed on the developing roll 5 is regulated into a thin layer by the toner regulating blade 2 having the level differences at least in the one or more parts of its surface which is in pressure-contact with the developing roll 5, and also it is electrified by friction caused between the regulating blade 2 and itself. By such a composition of the regulating blade 2 that the level differences are made in the one or more parts of its surface and by moving it to the next level difference part as needed, the blade 2 is prevented from being in contact with the developing roll 5 at one point all the time. Further, at least in one or more positions on the periphery of the regulating blade 2, a cleaning means is provided for cleaning the surface of the regulating blade 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing apparatus for developing an electrostatic latent image formed on an electrostatic latent image carrier by an electrophotographic process or the like by attaching toner, which is a fine powder. .

[0002]

2. Description of the Related Art An electrophotographic process, which is a printing technique used in copying machines and printers, forms an electrostatic latent image by charging and exposing a photosensitive member. Subsequently, the toner, which is a fine powder charged by the developing device, is attached to the electrostatic latent image on the photoreceptor, and the image is visualized. The visualized toner image is electrostatically transferred to a sheet, and is heated and fixed by a fixing device to form a copy or a printed image.

In this system, as a development process for visualizing an electrostatic latent image, a two-component development system using a toner and a carrier as a developer and a one-component development system using only a toner as a developer are known. The two-component developing method requires a density control device for keeping the mixing ratio of the toner and the carrier constant, and thus has the disadvantage that the device becomes complicated and large, and the device becomes expensive.

On the other hand, a one-component developing device is known as a developing device having a relatively simple structure. In particular, a non-magnetic one-component developing device using only non-magnetic toner has a simple configuration because no mag roll is required. The non-magnetic one-component developing device forms a thin toner layer having a predetermined toner layer thickness with a regulating blade disposed on a developing roll, and frictionally charges the toner by bringing the blade into contact with the toner. The developing roller on which the charged toner thin layer is formed contacts the photoconductor to visualize the electrostatic latent image formed on the photoconductor.

In this developing method, a thin metal plate, rubber, or a laminate thereof is generally used as a regulating blade, and a thin toner layer is formed on the developing roll by being brought into pressure contact with the developing roll. .

However, in this method, since the blade and the developing roll are always in pressure contact at a certain point, when the developing device is used for a long period of time, the toner adheres to the blade surface at the point of contact with the developing roll. Development or filming occurs. When filming occurs, a thin toner layer cannot be formed at that portion, so that vertical streaks occur on the developing roll and the charge amount tends to be unstable,
As a result, there is a problem that a defect occurs in the recorded image.

To solve this problem, Japanese Patent Application Laid-Open No.
In JP-A-60-233679, a cylindrical toner regulating member,
In Japanese Patent Application Laid-Open No. 2-109070, a belt-shaped toner regulating member is used, and by rotating them, the toner regulating member and the developing roll are always prevented from coming into contact at one point. Also,
A configuration in which a plate-like blade is wound as in JP-A-62-27772 has also been proposed.

[0008]

In the non-magnetic one-component developing system, it is necessary to prevent the occurrence of filming on the developing roll and the regulating blade. JP-A-60-2336
No. 79, a system using a cylindrical toner regulating member, and a configuration using a belt-shaped toner regulating member disclosed in JP-A-2-109070, the toner regulating member and the developing roll are always It prevents contact at one point. However, these methods have a shape in which the toner is easily entangled at the contact point between the toner regulating member and the developing roll, and the thickness of the toner layer tends to be unstable. further,
In the configuration using the belt-shaped toner regulating member, a meandering prevention mechanism is required because the belt meanders, and there is a disadvantage that the developing device becomes complicated. Further, in a configuration as disclosed in JP-A-62-27772 in which a plate-shaped blade is wound, since the toner fused on the blade is wound up,
It is difficult to wind up well.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a non-magnetic toner which can prevent filming of toner on a developing roll and a toner regulating blade, can prolong the life, and can stably control the amount of a thin toner layer on the developing roll. An object of the present invention is to provide a component developing device.

An object of the present invention is to provide a printing apparatus capable of performing stable high-quality recording by using these developing devices.

[0011]

In order to solve the above-mentioned object, the present invention uses a toner regulating blade provided with a plurality of steps on its surface.

Further, there is provided a measuring means for measuring the number of printed sheets, the number of rotations of the developing roll, the amount of toner adhered after development or the image density at at least one of the photosensitive member, the intermediate image forming member, the final recording member and the surface of the developing roll. In addition to the above, a rotating means for rotating the toner regulating blade to the next step portion as necessary based on the measurement results is provided.

Further, a cleaning means for cleaning the surface of the toner regulating member is provided at at least one position on the outer periphery of the toner regulating member.

The amount of the thin toner layer on the developing roll can be stably controlled by using a toner regulating blade having at least one step on its surface and controlling the contact position.

Further, by providing a rotating means for rotating the toner regulating member to the next step portion as necessary, the toner regulating member is prevented from always contacting the developing roll at one point, and the life of the developing device is extended. it can.

Further, by providing a cleaning means for cleaning the surface of the toner regulating member at at least one place on the outer periphery of the toner regulating member, the toner adhered to the toner regulating member can be removed, and the toner regulating member can be removed. Life can be extended.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a view showing an embodiment of the developing device of the present invention. In the figure, the toner 3 in the toner storage chamber 4 is sent to the supply roll 6 side by the conveying blade 7. Three transport blades 7 are arranged in succession in order to make the developing machine thin. Further, in order to prevent the toner from being excessively conveyed to the conveying roll side, the rotation speed becomes slower toward the rear side. The supply roll 6 made of a conductive foamed elastic material is disposed on a side surface of the development roll 5. The toner 3 sent to the supply roll 6 is rubbed against the development roll 5 by the supply roll 6, and a toner layer is formed on the surface of the development roll 5. The toner layer formed on the developing roll 5 is regulated to a thin layer by the toner regulating blade 2 having a step at least at one or more places on the surface that is in pressure contact with the developing roll 5. Charging is provided by friction.

FIG. 6 shows a configuration of a generally used non-magnetic one-component developing machine. The regulating blade 2 is generally made of a thin metal plate, rubber, or a combination of these. In this configuration, since the regulating blade 2 and the developing roll 5 are always in pressure contact at one point, when the developing device is used for a long time, there is a problem that filming occurs at the contact point. When filming occurs, a streak is formed on the thin toner layer on the developing roll 5, and the amount of adhesion and the amount of charge are reduced.

FIG. 3 shows a contact portion between the regulating blade and the developing roll of the developing device of the present invention. In order to solve such a problem, it is necessary to prevent the developing roll and the regulating blade from always contacting at one point. Therefore, in the present invention, the regulating blade has a configuration in which a plurality of steps are provided on the surface,
By moving it to the next step as needed,
It prevents contact with the developing roll at one point.

The time required for filming to occur depends on the pressure of the regulating blade, the softening point of the toner, the glass transition point, the fluidity, and the like, but tends to occur for about 8,000 A4 vertical prints. The time until this filming occurs is determined by the number of prints, the number of rotations of the developing roll, the amount of toner adhered after development, or the image density.
The measurement is made at least at one of the final recording material and the surface of the developing roll. By moving the contact position of the toner regulating blade to the next step on the basis of the measurement result, the regulating blade on the new surface can always be brought into contact with the developing roll, and the occurrence of filming can be prevented. it can.

Further, the toner fused to the surface of the regulating blade by the filming is cleaned by cleaning means 19 for cleaning the surface of the toner regulating member arranged around the regulating blade. Therefore, the life of the regulating blade can be prolonged. Cleaning means 19 for cleaning the surface of the toner regulating member
, A blade or brush made of rubber and metal is used.

In the non-magnetic one-component developing system, almost all of the thin toner layer formed on the developing roll by the regulating blade adheres to the image portion of the photoconductor. Therefore, the uniformity of the thin toner layer formed on the developing roll directly affects the final image. Therefore, on the surface of the developing roll,
A uniform thin toner layer must always be formed. Factors that change the thickness of the toner layer on the developing roll include the shape of the contact position between the regulating blade and the developing roll.

As shown in FIG. 5, when the regulating blade 2 has a columnar configuration, the toner 3 easily gets caught in the contact position between the regulating blade 2 and the developing roll 5, and the toner layer on the developing roll 5 becomes thick. I will. When the thickness of the toner layer on the developing roll 5 is increased, the amount of toner that does not come into contact with the blade and is not charged increases, which causes a problem that the toner adheres to a white print portion of an image. Therefore, the pressure for pressing the blade against the developing roll must be increased. When the blade pressure on the developing roll is increased, the load on the toner increases, so the time required for filming to be shortened and the load on the bearing of the developing roll also increases, so the driving torque also increases. Resulting in. In non-magnetic one-component development, it is preferable to form a thin toner layer by minimizing the blade pressure on the developing roll.

In the configuration of the present invention, since the surface of the regulating blade has a step, it is difficult for the toner to be caught in the contact position between the regulating blade and the developing roll. Therefore, a thin layer can be formed on the developing roll even if the pressure on the developing roll is reduced. Further, by changing the distance 19 from the contact point between the regulating blade and the developing roll to the tip of the step edge, the amount of toner adhesion can be controlled.
The closer the step portion of the regulating blade is to the contact position with the developing roll, the more difficult it is for the toner to be caught, so that the toner layer can be made thinner. Conversely, the further the step portion of the regulating blade is away from the contact position with the developing roll, the more easily the toner is entangled and the thicker the toner layer. Next, an embodiment of a color electrophotographic apparatus using the developing device of the apparatus of the present invention will be described. When the developing device of the present invention is applied, the driving torque is not increased due to toner filming and increased blade pressing, and the life of the non-magnetic one-component developing device can be extended. Originally, a non-magnetic one-component developing device has a simpler configuration than a two-component developing device, and is advantageous for miniaturization.

FIG. 2 shows an embodiment of a compact color electrophotographic apparatus using the developing device of the present invention. This is a color electrophotographic apparatus using a photoreceptor belt 8 and an intermediate transfer drum 9. Hereinafter, the printing process of the apparatus of FIG. 2 will be described. After the photoconductor 8 is uniformly charged by the charger 15, exposure is performed by the laser exposure device 13 in accordance with an image signal to form an electrostatic latent image on the photoconductor 8. The electrostatic latent image formed on the photoreceptor 8 is developed by the developing device 12Y of the present invention containing yellow toner. The developed image is electrostatically transferred to the intermediate transfer drum 9. After the transfer, the photoreceptor 8 has an erase lamp 18 for removing the electrostatic latent image.
And residual toner is cleaned by the blade cleaner 16. After the cleaning, the photoconductor 8 is charged and exposed again to form an electrostatic latent image on the photoconductor 8. The electrostatic latent image on the photoconductor 8 is developed by the developing device 12M of the present invention in which magenta toner is included, and a magenta image is formed on the photoconductor 8. The developing device is switched by moving away from the photoconductor. The magenta image of the photoconductor is transferred to the intermediate transfer drum 9 so as to overlap the yellow image. Subsequently, cyan and black images are formed by the same process, and are sequentially superimposed on the intermediate transfer drum 9. The intermediate transfer drum 9 on which the four-color images are superimposed is collectively transferred 7 onto the paper conveyed from the paper cassette 14 to form a four-color image on the paper. The residual toner on the intermediate transfer drum 9 on which the image has been transferred on the paper is cleaned by the cleaner 10. The sheet on which the image transfer has been performed is destaticized and peeled from the intermediate transfer drum, and is heated and melted by the fixing device 11 to become a final image.

[0027]

According to the non-magnetic one-component developing machine of the present invention, filming can be prevented from occurring on the regulating blade and the surface of the developing roll, so that a stable developing ability can be obtained even if the developing machine is used for a long time. .

Further, in the developing machine of the present invention, the toner layer pressure can be controlled by changing the distance from the contact point between the regulating blade and the developing roll to the step edge.

The size of the developing device in the embodiment is 280 × 1
The developing device is about 60 × 40 mm and can contain about 150 g of toner. This is a capacity capable of recording more than 8,000 images with a print density of 5% with a toner adhesion amount of 0.6 to 1.0 mg per cm ² . In this embodiment, a full-color printer using four developing units is used. However, the size of the entire apparatus is reduced to about 490 × 480 × 330 mm, about 77.6.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of one embodiment of a non-magnetic one-component developing device of the present invention.

FIG. 2 is an explanatory diagram of one embodiment of a full-color recording apparatus using the developing device of the present invention.

FIG. 3 is an explanatory view of the vicinity of a regulating blade contact point of the present invention in the embodiment of FIG.

FIG. 4 is an explanatory diagram of another embodiment of the non-magnetic one-component developing device of the present invention.

FIG. 5 is an explanatory diagram near a contact point of a conventional cylindrical regulating blade.

FIG. 6 is an explanatory diagram of conventional non-magnetic one-component development.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Photoreceptor, 2 ... Regulator blade, 3 ... Toner, 4 ... Toner storage chamber, 5 ... Developing roll, 6 ... Conveyance roll, 7 ... Rotating stirring blade, 12 ... Developing device.

Claims (5)

[Claims] An image forming apparatus according to claim 1, wherein a toner regulating member is brought into contact with the developing roll under pressure to form a charged toner thin layer on the developed roller.
In a one-component developing apparatus for visualizing an electrostatic latent image by bringing it into contact with an electrostatic latent image carrier on which an electrostatic latent image has been formed by an electrophotographic process or the like, a plurality of toner regulating members are provided on the surface. A one-component developing apparatus characterized by having a step. 2. A toner regulating member surface having a step on the surface of the developed device when the one-component developing device according to claim 1 develops an electrostatic latent image on the developed latent image carrier. A one-component developing device configured such that the stepped portion of the developing roller comes into fixed contact with a position slightly upstream in the rotation direction of the developing roll from the contact position between the already-toner regulating member and the already-developed roll. 3. The one-component developing device according to claim 1, wherein the toner regulating member is configured to be movable. 4. The method according to claim 3, wherein the number of printed sheets, the number of rotations of the developing roll, the amount of toner adhered after development, or the image density are measured at least at one of the photosensitive member, the intermediate image forming member, the final recording member or the developing roller surface. A one-component developing apparatus having a unit for measuring and a unit for controlling a contact position of the toner regulating member based on the measurement result. 5. The toner regulating member according to claim 3, wherein:
A one-component developing device in which cleaning means for cleaning the surface of the toner regulating member is disposed at least at one position on the outer periphery.