JPH05107910A - One-component developing device - Google Patents

Abstract

PURPOSE:To provide a one-component developing device in which the lowering of image density is little even when development is repeated many times and the development with equal image density is always performed. CONSTITUTION:In a developer stirring chamber 5 for supplying developer to a developer carrier 3, the developer is not fed in the axial direction of the developer carrier 3, but it is fed to be equally distributed in the axial direction of the carrier 3 in a developer feeding chamber 7 which is separately provided from the developer stirring chamber 5. Furthermore, a horizontal feeding device 9 by which the developer stored in the developer chamber 7 is fed in a horizontal direction and equally supplied in the axial direction of the developer carrier in the developer stirring chamber 5 is provided. Thus, load is received by a developer regulating member 4 and the developer whose electristatically charged amount is lowered is prevented from being deviated and accumulated at the end in the width direction of a formed image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device which is used in an image forming apparatus such as an electrophotographic copying machine or a printer, and which makes a developer adhere to an electrostatic latent image to visualize it. The present invention relates to a developing device that is used for developing.

[0002]

2. Description of the Related Art As a developing device using a one-component developer,
For example, the one shown in FIG. 3 has been conventionally known.
FIG. 3A is a schematic cross-sectional view showing the configuration of this developing device, and is a view in a cross section perpendicular to the axial direction of the developer carrier, and FIG. 3B is a cross-sectional view of the developer carrier in the axial direction. It is explanatory drawing which shows a structure. In this one-component developing device, a plurality of magnets are arranged immovably in a rotatable cylindrical sleeve,
A developer carrying member 103 that adsorbs and conveys the developer on the sleeve, and a developer holding member 103 that is arranged so as to be in pressure contact with the developer carrying member 103, regulates the developer adsorbed on the surface of the developer carrying member, and forms a thin layer. The developer regulating member 104 is contained in the housing 101.

The housing 101 is a developer carrying member 103.
Has an opening on the front side facing the electrostatic latent image holding member 102, and a stirring chamber 105 for conveying and stirring the developer T along the developer carrying member 103 is formed on the rear side thereof.
Inside the stirring chamber 105, there is provided a carrying and supplying member 106 which is arranged in parallel to the developer carrying member 103 and which carries the developer and supplies it to the developer carrying member 103 while rotating and stirring.

Further, one end of the stirring chamber 105 along the axial direction of the developer carrying member 103 communicates with a developer carrying-in passage 115 as shown in FIG. 3 (b). A developer supply box 116 is provided above the developer carry-in path 115, and a developer supply device 117 appropriately drops a necessary amount of developer T into the developer carry-in path 115 to replenish it. Is becoming Further, the conveyance supply member 106 forms a screw in which the spiral blade 106a is attached to the rotation shaft in the developer carry-in passage 115, and the developer supply box 116 is provided.
The developer T replenished from the inside is conveyed into the stirring chamber 105.

In such a one-component developing apparatus, the developer T supplied into the agitating chamber 105 is transported and supplied by the carrying and supplying member 10.
6 is gradually conveyed toward the other end of the stirring chamber 105. Along with this, the developer supplied to the developer carrying member 103 and adsorbed on the surface thereof is made into a thin layer by the developer regulating member 104, and the developer carrying member 103 is transferred to the developing area facing the electrostatic latent image holding member 102. Is transported. The developer that has not contributed to the development is carried into the housing 101 again as the developer carrying member 103 rotates, and is separated from the developer carrying member 103.

[0006]

However, such a developing device has the following problems. When the developer T is conveyed in the axial direction of the developer carrier (the width direction of the image to be developed) as described above, and the carrier is adsorbed to the surface of the developer carrier and repeatedly conveyed to the developing area and peeled off, agitation occurs. The developer carried into the chamber 105 is repeatedly stored in the developer regulating member 1
While being rubbed by 04, it is gradually conveyed in the conveyance direction of the conveyance supply member 106. For this reason, the developer on the other end side, that is, near the end on the side ahead in the transport direction of the stirring chamber 105 is more loaded than the developer on the side to which the developer supply box 116 is attached. However, there is a phenomenon in which an external additive (silica or the like) added to the developer for adjusting the charge amount is embedded in the toner or separated from the toner. On the leading end side in the transport direction where a large amount of the developer in which such an abnormality has occurred is accumulated, the charge amount of the developer is lower than that on the side where the developer supply box 116 is present, and the density of the developed recorded image is reduced. Occurs. For this reason, uneven density occurs within the width of the image, and a good image cannot be obtained.

This problem is not unique to a developing device of a type in which a developer is pressed by a developer regulating member (blade) pressed against a developer carrying member to form a thin layer. As shown in FIG. 4, even in the developing device of the type in which the thin layer of the developer is formed by the trimming member 118 which is not in contact with the developer carrying member, the developer is loaded by the trimming, and the above-mentioned problem occurs. Occurs.

In order to prevent the occurrence of such density unevenness within the width of the image, the developer may be supplied evenly in the axial direction of the developer carrying member. It may become large. When the developing device has a large size in the height direction, in an image forming device in which a large number of devices for charging, exposing, developing, transferring, cleaning, etc. are arranged in a limited space around the electrostatic latent image holding member. However, there is a problem that the entire device becomes large. In particular, in a color image forming apparatus in which a plurality of developing devices are arranged to perform multicolor development, an increase in size of the developing device in the height direction is directly linked to an increase in size of the image forming device itself, which is an important problem.

The present invention has been made in view of the above problems, and an object thereof is to make the developing device substantially uniform in the axial direction with respect to the developer carrier without increasing the size in the height direction. It is an object of the present invention to provide a one-component developing device that can supply various developers and can always perform development with a uniform image density in the width direction of an image, even if development is repeated many times.

[0010]

In order to solve the above-mentioned problems, the present invention has a cylindrical shape or a circular shape which is arranged so as to face an electrostatic latent image holding member and which carries a one-component developer by adhering it to the surface thereof. A columnar developer carrying member, a developer regulating member that regulates the amount of the developer attached to the developer carrying member, and the developer that is provided along the axial direction of the developer carrying member while stirring the developer. In a one-component developing device having a developer stirring chamber capable of supplying the developer to substantially the entire axial length of the carrier, in a rear side of the developer stirring chamber opposite to the side facing the developer carrier. A developer transport chamber that is provided over substantially the entire length of the developer stirring chamber, is separated from the developer stored in the developer stirring chamber, is temporarily stored, and is transported so as to be evenly distributed. , Supply the developer to this developer transfer chamber An image agent supply unit, a developer transport device that transports the developer, which has been supplied to the developer transport chamber and is temporarily stored, so as to be evenly distributed in the axial direction of the developer carrier, and the developer transport chamber. In the developer agitating chamber, the developer, which is substantially evenly distributed in the developer carrying member, is conveyed in a substantially horizontal direction at a right angle to the axial direction of the developer carrying member, and is evenly supplied in the developer carrying member axial direction of the developer stirring chamber. And a supply mechanism.

Further, in the above-mentioned one-component developing apparatus, it is preferable that the uniform supply mechanism includes a mechanism for reciprocating an upright surface continuous in the axial direction of the developer carrying member in a direction substantially perpendicular to this surface. ..

The developer carrying chamber is formed, for example, by arranging a uniform cross-section member having a concave portion having an opening at the top along the developer stirring chamber in the axial direction of the developer carrier, and the uniform developer supplying mechanism is It is possible to provide a mechanism in which the uniform cross-section member is rotated around its axis to discharge the developer from the upper opening, and to convey the developer in a substantially horizontal direction. Further, the mechanism for reciprocating the vertical continuous surface of the developer carrying member,
It may be independently driven, or may be linked with other parts of the developing device. Further, various mechanisms such as a mechanism including a crank mechanism for reciprocating movement and a mechanism utilizing a restoring force of a spring member for movement in one direction can be adopted. The developer transport device for transporting the developer in the developer transport chamber is a device having a screw-shaped protruding blade or a developer carrier in which a spiral carrier member is attached to a rod-shaped member arranged in the axial direction. There can be various structures that can be transported in the axial direction.

[0013]

In the one-component developing device having the above-described structure, the developer transport chamber for separating the developer supplied from the developer supply unit from the developer in the developer stirring chamber and temporarily storing the developer is the developer stirring chamber. The developer transport device is provided in the developer transport chamber, so that the developer is once supplied from the developer supply section to the developer transport chamber and transported by the developer transport device. Thus, the developer carrier is evenly distributed in the axial direction. Further, since the one-component developing device is provided with the uniform supply mechanism for supplying the developer from the developer transport chamber to the developer stirring chamber, the developer evenly distributed in the developer transport chamber is Is almost uniformly supplied in the axial direction of the developer carrier. In the developer agitating chamber, the developer is agitated and supplied to the developer carrying member, but the developer is not conveyed in the axial direction of the developer carrying member. The developer is evenly distributed.

The developer supplied to the developer carrying member is regulated by the developer regulating member and is subjected to a load. The loaded developer is evenly distributed in the axial direction of the developer bearing member. The amount of the developer in which the abnormality of the external additive has occurred due to the load is not increased in part. Therefore, the image density does not decrease in a part in the axial direction of the developer carrying member, and the decrease in the image density as a whole is reduced.

Further, the developer carrying chamber is provided behind the surface of the developer agitating chamber opposite to the surface facing the developer carrying member, and the uniform feeding mechanism feeds the developer substantially at right angles to the axial direction of the developer carrying member. Since the developer carrier can be conveyed in a substantially horizontal direction, the developer can be developed as described above even if the developer carrier, the developer stirring chamber and the developer transport chamber are arranged in a substantially horizontal direction. The developer can be supplied from the agent transport chamber to the developer agitating chamber, and by arranging the developer substantially horizontally, the vertical dimension of the housing can be reduced.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a one-component developing device which is an embodiment of the present invention, and FIG. 1 (a) is a schematic cross-sectional view in a direction perpendicular to a width direction of an image to be developed, and FIG. )
FIG. 2 is a schematic cross-sectional view taken along line I-I shown in FIG. In this developing device, a developer carrier 3 for adsorbing and transporting the developer on the surface is supported in a housing 1 having an opening, and in the housing 1, the developer carrier 3 above The developer regulating member 4 that regulates the amount of developer adhered, the developer stirring chamber 5 that stores the developer supplied to the developer carrying member 3 while stirring, and the developer stirring chamber 5 are isolated from each other to temporarily store the developer. A developer transport chamber 7 for storing the developer is provided. Further, the developer transport chamber 7 is provided with a screw auger (developer transport device) 8 therein, and the developer transport chamber 7
A horizontal transfer device 9 for supplying the developer to the developer agitating chamber 5 is provided below.

The developer carrying member 3 is arranged so as to face the electrostatic latent image holding member 2, and is provided with a rotatable cylindrical sleeve 3b on the outer periphery of a substantially cylindrical magnet roll 3a which is fixed and supported. Is. The magnet roll 3a is provided with S poles and N poles along its circumference. The arrangement of these magnetic poles is such that a magnetic field for adsorbing the developer is formed along the surface of the cylindrical sleeve 3b, and the developer can be adsorbed on the surface of the developer carrier 3 and conveyed. ing. One end of the developer regulating member 4 is the housing 1
Near the other end of the elastic member 4a fixed to the elastic member 4a, a soft elastic member that is pressed against the surface of the developer carrying member 3 is provided.
The developer adsorbed on the surface of the developer carrier can be thinned and an electric charge can be applied.

The developer agitating chamber 5 is provided along substantially the entire length of the developer carrying member 3 along the axial direction thereof, and is provided with a conveying and supplying member 6 for agitating the developer and supplying it to the developer carrying member 3. There is. The conveyance supply member 6 has a rotation axis parallel to the axial direction of the developer carrier, and the additional member 6a attached to the rotation shaft rotates to stir the developer and supply the developer to the developer carrier 3. .. A toner sensor 12 is attached to the wall portion of the developer stirring chamber 5 so that the remaining amount of the developer in the developer stirring chamber 5 can be detected.

The developer transport chamber 7 is formed by arranging an arc cross-section member 11 having an opening at the top and a downwardly convex arc-shaped cross section in the axial direction of the developer carrier, and shielding both ends. The developer stirring chamber 5 is disposed at the rear of the side opposite to the side facing the developer carrying member 3. This developer transfer chamber 7
Is provided over substantially the entire length of the developer agitating chamber 5, and the above-mentioned arc-shaped cross-section member 11 has an opening at the top thereof having a central angle of about 120 ° or less. This arc section member 1
The reference numeral 1 is adapted to rotate around its axis so that the opening moves from the upper part to the developer stirring chamber side, and a projection 11a is provided on the outer peripheral surface on the upstream side in the rotation direction of the opening. ..

A developer supply unit 10 is connected to one end of the developer transport chamber 7, and a supply valve 10b is supplied based on a signal detected by a toner sensor 12 provided in the developer stirring chamber 5.
Is operated and the developer is supplied from the hopper 10a into the developer transport chamber 7. Inside the developer transport chamber 7, there is provided a screw auger 8 (developer transport device) rotatably supported with a spiral-shaped protruding blade, and the developer transport chamber 7 is rotated by the screw auger 8.
The developer supplied inside can be transported so as to be evenly distributed in the axial direction of the developer transport chamber 7 (width direction of the image to be developed).

The horizontal transfer device 9 is provided below the developer transfer chamber 7 and transfers the developer in a substantially horizontal direction which is substantially perpendicular to the axial direction of the developer carrying member.
A plate-shaped member 9a that is continuous in the axial direction of the developer carrier and is supported substantially vertically, and slides along the guide hole of the housing 1 in a direction perpendicular to the surface of the plate-shaped member 9a that supports the plate-shaped member 9a. It is composed of a possible support rod 9b, a coil spring 9c provided on the outer periphery of the support rod 9b, and a telescopic tubular member 9d that covers the coil spring 9c and the support rod 9b. Further, a protrusion 9e that engages with the protrusion 11a of the arcuate cross-section member 11 is provided on the upper portion of the plate-shaped member 9a.

In the one-component developing device as described above, when the developing operation is repeated and the developer in the developer agitating chamber 5 is consumed and becomes lower than a preset level, the developer is provided in the developer agitating chamber 5. The supply valve 10b is opened by a signal from the toner sensor 12 provided, and the developer in the hopper 10a is introduced into the developer transport chamber 7.

When a preset amount of the developer is introduced into the developer transport chamber 7, the supply valve 10b is closed and the supply of the developer into the developer transport chamber 7 is stopped. The developer in the developer transport chamber is transported by the rotation of the screw auger 8 so as to be uniformly distributed in the developer transport chamber 7 in the image width direction. The screw auger 8 is always rotated during the operation of the developing device.

FIG. 2 shows the developer transport chamber 7 to the developer stirring chamber 5.
FIG. 6 is an explanatory diagram sequentially showing a state in which the developer is uniformly supplied. When the time required for the developer in the developer transport chamber 7 to become uniform has elapsed, the arcuate cross-section member 11 forming the developer transport chamber 7 rotates in the direction of the arrow in the figure.
[Fig. (A)] When the arc-shaped cross-section member 11 is further rotated, the projection 11a in the vicinity of the opening of the arc-shaped cross-section member 11 causes the horizontal conveyance device 9 to move.
Engages with the protrusion 9e. [Figure (b)]

The protrusion 9e is fixed to the plate-shaped member 9a, and the coil spring 9c is rotated as the arc-shaped cross-section member 11 rotates.
It moves in a direction substantially perpendicular to the axial direction of the developer carrying member against the repulsive force of. At this time, the opening of the arc-shaped cross-section member 11 faces downward, and the developer in the developer transport chamber 7 falls to the position in front of the moved plate-shaped member 9a. [Figure (c)]

When the arcuate section member 11 is further rotated, the projection 11a of the arcuate section member 11 and the projection 9e of the horizontal conveying device 9 are rotated.
And the plate-shaped member 9a moves in a direction substantially perpendicular to the axial direction of the developer carrier while pushing the developer in front by the restoring force of the coil spring 9c. [FIG. (D)] By such an operation, the developer, which is substantially evenly distributed in the axial direction of the developer carrier, is conveyed into the developer stirring chamber 5 substantially evenly. It should be noted that the operations of FIGS. (A) to (d) may be performed several times in succession to more reliably carry the developer.

Further, since the expandable / contractible cylindrical member 9d for covering the support rod 9b and the coil spring 9c is attached to the horizontal transfer device 9, the guide hole and the coil spring 9c are clogged with the developer, and the horizontal transfer device 9 is attached. There is no risk of hindering the above-mentioned reciprocating motion of the.

The developer thus carried into the developer stirring chamber 5 is supplied to the developer carrier 3 by the rotation of the carrying and supplying member 6. Further, the developer is a cylindrical sleeve 3b.
With the rotation of, the developer carrying member 3 and the electrostatic latent image holding member 2 are conveyed close to each other and are conveyed to the developing area, and are consumed by the developing. Along with this, when the amount of developer stored in the developer stirring chamber 5 decreases, the toner sensor 12
Is detected and the above-described process of supplying the developer to the developer stirring chamber is repeated. In this way, the developer is evenly supplied in the image width direction of the developer stirring chamber, and the occurrence of image density unevenness in the image width direction is prevented.

[0029]

As described above, in the one-component developing apparatus of the present invention, the developer is temporarily stored in the developer carrying chamber provided along the axial direction of the developer carrying member (the width direction of the image to be developed). After being introduced, the developer carrier is conveyed so as to be evenly distributed in the axial direction, and then is supplied to the developer stirring chamber by the uniform supply mechanism. Almost no developer is conveyed in the axial direction.
For this reason, a large amount of developer attached to the surface of the developer bearing member and receiving a load, resulting in a decrease in charge amount, does not accumulate at one end in the width direction of the image. It will be evenly distributed. Therefore, even if the development is repeated a number of times, the image density is not significantly reduced, and good development can be performed without causing unevenness in the image density at one end and the other end in the width direction of the image. Further, the developer carrier, the developer stirring chamber, and the developer transport chamber are arranged side by side in a substantially horizontal direction, and the uniform supply mechanism transports the developer substantially horizontally and supplies it to the developer stirring chamber. Therefore, it is not necessary to increase the vertical dimension of the housing, and the housing can be arranged in a small space around the electrostatic latent image holding member.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a one-component developing device which is an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an operation of a uniform supply mechanism used in the one-component developing device of the above embodiment.

FIG. 3 is a schematic sectional view showing a conventional one-component developing device.

FIG. 4 is a schematic sectional view showing another example of a conventional one-component developing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Electrostatic latent image holder 3 Developer carrier 4 Developer regulation member 5 Developer stirring chamber 6 Transport supply member 7 Developer transport chamber 8 Screw auger (developer transport device) 9 Horizontal transport device 10 Developer supply Part 11 Arc section member 12 Toner sensor

Claims (2)

[Claims] 1. A cylindrical or columnar developer carrying member which is arranged so as to face the electrostatic latent image holding member and which conveys a one-component developer while adhering to the surface thereof, and a developing device attached to the developer carrying member. A developer regulating member that regulates the amount of the developer and a developer provided along the axial direction of the developer carrier can stir the developer and can supply the developer to substantially the entire axial length of the developer carrier. In a one-component developing device having a developer agitating chamber, the developer agitating chamber is provided behind the side opposite to the side opposite to the developer carrier, and is provided over substantially the entire length of the developer agitating chamber. A developer transport chamber that is separated from the developer stored in the developer agitating chamber, is temporarily stored, and is transported so as to be evenly distributed; and a developer supply unit that supplies the developer to the developer transport chamber. Supplied to the developer transfer chamber and temporarily stored Developer,
A developer transport device that transports the developer carrier so as to be evenly distributed in the axial direction, and a developer that is substantially evenly distributed in the developer transport chamber in a direction substantially perpendicular to the axial direction of the developer carrier. A one-component developing device, which has a uniform feeding mechanism that feeds in a substantially horizontal direction and supplies the developer agitating chamber axially in a substantially uniform manner. 2. The one-component developing device according to claim 1, wherein the uniform supply mechanism reciprocates an axially continuous vertical surface of the developer carrier in a direction substantially perpendicular to the vertical surface. A one-component developing device comprising: