JPH0830084A - One-component developing device - Google Patents

Abstract

PURPOSE:To provide a developing device capable of obtaining the image of a uniform and stable density, without biasedly heaping toner having a small charge quantity such as deteriorated toner and small grain size toner, in the developing device in a developing device using a one-component developer. CONSTITUTION:The one-component developing device is provided with two toner carrying paths 5 and 6 arranged side by side along a developing roll 3 in a housing 1 and communicated in both end parts in the axial direction of the developing roll, a first stirring/carrying member 7 carrying the toner from a side not having a side guiding member to a side having it in the toner carrying path 5 of the side adjacent to the developing roll, a second stirring/ carrying member 8 carrying the toner in the opposite direction in the toner carrying path 6 and moreover, a toner supplying part 9 for supplying fresh toner to the toner carrying path 6 which is not adjacent to the developing roll 3. Thus, the fresh toner is carried from a low toner consumption side to a high toner consumption side, to be consumed before deteriorating.

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 visualizes a developer by attaching it to an electrostatic latent image. And a developing device 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. 4 has been conventionally known.
In this developing device, a plurality of magnets are fixedly arranged in a rotatable cylindrical sleeve, and a developer carrier 103 for adsorbing and conveying the developer on the sleeve, and a developer carrier 103 A developer regulating member 104 that is arranged so as to be in pressure contact and regulates the developer adsorbed on the surface of the developer carrier and thins the layer is housed 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 transporting the developer T and stirring is formed along the developer carrying member 103 at the rear side. . In the agitation chamber 105, a conveyance supply member 106 that is arranged in parallel with the developer carrier 103 and conveys the developer and supplies the developer to the developer carrier while rotating and stirring as shown in FIG. Is provided, and a detection device 107 that detects the amount of developer in the stirring chamber is attached to the wall surface. Further, one end of the stirring chamber 105 along the axial direction of the developer carrying member 103 has a developer carrying-in path 1 as shown in FIG.
15 and is connected to the developer feeding path portion continuously from the stirring chamber. A developer supply box 116 is provided above the developer carry-in path 115, and a necessary amount of the developer T is appropriately supplied by driving the dispensing member 117.
It is designed to be dropped into 5.

In such a developing device, the developer introduced into the developer carry-in passage 115 is conveyed and supplied to the developer supply passage 115 as indicated by an arrow A in FIG.
6 is positively conveyed by a screw 106c that constitutes a part of the nozzle 6, and a rod-shaped member is gradually conveyed toward the other end of the agitating chamber 105 by an agitating unit attached substantially parallel to the rotating shaft. Along with this, the developer supplied to the developer carrier 103 and adsorbed on the surface thereof is the developer regulating member 10
In step 4, the developer carrying member 103 is made into a thin layer and is conveyed to the developing area facing the electrostatic latent image holding member 102. 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.

Further, when the developer is consumed by the repeated development and the remaining amount of the developer in the stirring chamber 105 becomes small, the detection device 107 detects this and outputs a signal. Based on this signal, the dispensing member 117 provided in the developer supply box 116 is driven, and the developer carry-in path 1
The developer is dropped into 15.

However, the above-described developing device has the following problems. When the developer T is conveyed in the axial direction of the developer carrier and is repeatedly adsorbed to the surface of the developer carrier and conveyed to and separated from the developing area, the developer carried into the agitation chamber 105 is repeatedly conveyed. Is also rubbed against the developer regulating member 104. Therefore, the stirring chamber 10
The developer on the other end side, that is, near the end on the side ahead in the transport direction receives a larger load than the developer on the side on which the developer supply box 116 of 5 is attached, and the charge amount is reduced. External additives (silica, etc.) added to the toner for adjustment
The phenomenon that the toner gets into the toner or separates from the toner (this is referred to as deterioration below).
Is occurring. On the downstream side in the transport direction of the stirring chamber where a large amount of developer in which such an abnormality has occurred is accumulated, the charge amount of the developer is
It becomes lower than the side where the developer supply box 116 is located.

Further, the developer particles having a smaller particle diameter than the appropriate particle diameter contained in the developer and the developer particles having a large particle diameter are difficult to obtain a necessary charge amount, and most of them do not contribute to the development. It remains on the carrier and is returned to the stirring chamber. For this reason, a large amount of toner having a small particle size and a large particle size is deposited on the end of the stirring chamber opposite to the developer supply side, and the charge amount of the developer is lower than that on the supply side. In the vicinity of the edge where a large amount of developer with such abnormalities or small particle size / large particle size developer accumulates, the image developed compared to the developer supply side on the opposite side due to insufficient charge However, there is a problem in that the concentration of

Therefore, in Japanese Unexamined Patent Publication (Kokai) No. 5-107908, a partition member 20 for partitioning a stirring chamber as shown in FIG.
There is shown a device in which the two conveying paths 205 and 206 are partitioned by 1a, communicated at both ends thereof, and the developer is circulated by respective stirring and conveying members 207 and 208 as shown in FIG. In this apparatus, the toner supplied to the one end 205 ′ of the transport path 205 is sent to the transport path 205 by a screw having a transport blade that spirally protrudes from the peripheral surface of the rotating shaft 207a of the transport member 207,
Further, the spiral member gently conveys the conveying path 205 to the opposite side.

[0009]

However, the above-mentioned developing device still has the following problems. In the image forming apparatus using the developing device as described above, the sheet on which the toner image is transferred is generally conveyed along a side guide member (side register) provided on one side of the sheet conveying path. Therefore, even if the size of the paper is large or small, an image is always formed on the side guide member side, and the consumption amount of toner in the developer is large on the side guide member side. In the developing device used in such a state, when the developer is supplied from the guide member side, which is the side that consumes a large amount of the developer, in the stirring chamber on the side adjacent to the developing roll, only the new toner supplied is supplied. Is consumed, and the deteriorated toner and the toner of large and small particle diameters are conveyed to the toner delivery section at the end opposite to the toner supply side, and the charge amount of this section is reduced and the image density is reduced. Therefore, the density of the developed image becomes non-uniform. Further, there is a problem that deteriorated toner accumulates in the developing device without being used, and it is difficult to maintain a stable density for a long period of time.

The present invention has been made in view of the above problems, and an object thereof is to prevent deteriorated toner and toner having large and small particle diameters from accumulating on a part of the stirring chamber, and for a long period of time. Another object of the present invention is to provide a developing device capable of forming a stable image without a decrease in density.

[0011]

In order to solve the above problems, the developing device of the present invention conveys one side edge of a sheet along a side guide member fixedly supported,
A developing device used in an image forming apparatus for transferring a toner image formed on an image carrier onto the sheet, the device being arranged to face the image carrier, carrying a one-component developer on the surface, and carrying the developer. Developing roller, two toner conveying paths that are arranged in parallel along the developing roller and communicate with each other at both ends in the axial direction of the developing roller, and one of the two toner conveying paths that is adjacent to the developing roller. A first agitating / conveying member provided in the toner conveying path for conveying toner from a side not provided with the side guide member to a side provided with the side guide member; A second stirring / transporting member provided in the other toner transporting path for transporting toner in a direction opposite to that of the first stirring / transporting member; and a toner transporting member provided with the second stirring / transporting member. On the road or first A toner supply unit for supplying toner is provided on the upstream side of the toner conveyance path provided with the stirring conveyance member.

As the first stirring / transporting member and the second stirring / transporting member, a member formed by spirally forming a plate member, a rod member or the like, or a combination of these members rotatably supported is preferably used. However, it is desirable to have a structure that does not apply an excessive load to the toner. Further, the toner supply section may be provided at a position where new toner can be supplied from the upstream side to the toner conveyance path on the side adjacent to the developing roll, but for the convenience of handling, it is provided on the front side of the image forming apparatus. desirable.

[0013]

In the single-component developing device having the above-described structure, the two toner transport paths arranged in parallel along the developing roll communicate with each other at both ends in the axial direction of the developing roll, and are located on the side adjacent to the developing roll. In the toner conveying path, the first stirring and conveying member conveys the toner from the side where the side guide member is not provided to the side where the side guide member is provided, and the second agitating and conveying member conveys the toner to the second side in the other toner conveying path. The agitating and conveying member conveys the toner in the opposite direction. Therefore, in the toner transport path on the side adjacent to the developing roll that consumes toner,
Since new toner is supplied from the side with the least toner consumption, the toner is agitated by the agitating / conveying member, the toner remaining in the conveying path and the newly supplied toner are evenly mixed, and the toner consumption A large number of side guide members are conveyed and used for development. Therefore, the difference in the amount of deteriorated toner and the amount of toner containing large and small particle diameters between the upstream side and the downstream side of the stirring chamber becomes small, and it is possible to reduce the occurrence of density difference in images.

Further, as the toner is conveyed, deterioration of the toner progresses and at the same time, the amount of toner consumption increases.
Toner that has deteriorated to some extent also contributes to development and is consumed,
The amount of toner that is extremely deteriorated is reduced. This allows
It is possible to prevent the abnormal developer from accumulating in the developing device, and maintain a stable concentration for a long period of time.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing the structure of a one-component developing device which is an embodiment of the present invention, and FIG. 2 is a line II shown in FIG.
It is a schematic diagram showing composition of a section. In this developing device, the developing roll 3 (developer carrier) is partially exposed at a portion of the housing 1 that is open facing the image carrier 2 and the image carrier 2
It is provided to rotate in close proximity to the blade 4
The (developer regulating member) is pressed against this developing roll. A toner conveying path is provided in the housing 1 on the side opposite to the side where the developing roll 3 faces the image carrier 2, and the toner conveying path is partitioned by the partition member 1a. It is composed of two toner transport paths 5 and 6 which communicate with each other.

The first stirring for stirring the developer in the toner transport path 5 and for transporting the toner in the axial direction of the developing roll 3 from the direction without the side guide member (the direction of the arrow in FIG. 2). In addition to having the transport member 7, the toner transport path 6 is provided with the second stirring transport member 8 that transports the developer in the opposite direction. Further, in the present embodiment, a toner carrying-in path 6'is connected to one end of the toner carrying path 6 in the developing roll axial direction, and a toner supply box 9 is provided above the toner carrying-in path 6 '. .

The developing roll 3 described above comprises a rotatable cylindrical sleeve disposed on the outer periphery of a fixedly supported substantially cylindrical magnet member. A developing pole N ₁ , a transport pole S ₁ , and an attraction pole N are attached to the magnet member by a magnetizing method.
₂ and repulsion poles S ₂ and S ₃ are provided so that the magnetic developer attracts and peels the magnetic developer. The blade 4 is for thinning the magnetic developer adsorbed on the outer peripheral surface of the developing roll, and the portion in pressure contact with the developing roll is made of a soft elastic member. The soft elastic member is supported near one end of an elastic support member such as a stainless plate, and the other end of the elastic support member is fixed to the housing.

The toner conveying paths 5 and 6 have a first agitating and conveying member 7 and a second agitating and conveying member 8, respectively, and the partition member 1a between the toner conveying paths 5 and 6 is a shaft of the developing roll 3. An opening having a width of 30 mm is provided at both ends in the direction, and forms a communicating portion with the toner conveying paths 5 and 6. In the present embodiment, the first agitating / conveying member 7 and the second agitating / conveying member 8 are spiral agitators 7b in which linear members each having a spiral shape with an outer diameter of 26 mm are attached around the rotating shafts 7a, 8a. , 8b, and an end portion 6'corresponding to a portion directly below the toner supply portion of the second stirring / conveying member 8 is spirally projected from the peripheral surface of the rotating shaft having a higher conveying ability as shown in FIG. The blade 8c for conveyance which consists of a conveyance blade was provided. In addition, here, the first stirring and conveying member 7, the second
Each of the agitating and conveying members 8 conveys the toner in the direction indicated by the arrow in FIG.

In the developing device as described above, the toner dropped from the toner supply box 9 is moved by the second agitating / conveying member in the toner conveying path 6 which is not adjacent to the developing roll and is indicated by an arrow shown in FIG. It is stirred and conveyed in the direction. Further, it is fed through the opening of the partition member 1a into the toner transport path 5 adjacent to the developing roll, and is transported in the direction indicated by the arrow in the figure from the side where the side guide member is not provided. Is supplied to. The toner supplied to the surface of the developing roll is thinned by the blade 4 as the developing roll rotates, is conveyed to a developing area in the vicinity of and facing the image carrier 2, and is transferred to the image carrier for development.

The toner that has not contributed to the development and remains on the developing roll is returned to the toner conveying path 5 again and is carried into the toner conveying path 6 side from the opening of the partition member 1a by the first stirring and conveying member. Then, it is agitated along with the new toner that has just been supplied in the toner carrying path 6 and is again fed into the toner carrying path 5. As the toner deteriorates in this way, the toner is conveyed to a portion that consumes a large amount of toner, so toner with a low charge amount or abnormal toner does not accumulate unevenly, and the deteriorated toner is also used for development. To be For this reason, the deteriorated toner does not accumulate and the distribution of the deteriorated toner is not largely biased, and an image having a uniform density can be obtained for a long period of time.

[0021]

As described above, in the one-component developing device of the present invention, the toner is supplied to the two toner carrying paths by the agitating and carrying members of the two toner carrying paths which communicate with each other at both ends in the axial direction of the developing roll. In the toner conveying path on the side adjacent to the developing roll, the toner is conveyed from the side where the side guide member is not provided to the side where the side guide member is provided. For this reason, the toner that is supplied to the developing roll and is about to deteriorate is supplied to the side guide member side that consumes a large amount of toner and is used for development, so that the toner with a low charge amount is biased to the downstream side of the toner conveyance path. And a stable density image can be obtained. Further, the chance of consumption is increased before the deterioration progresses, and the deteriorated toner is not accumulated and unevenly accumulated.

[Brief description of drawings]

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

FIG. 2 is a schematic view showing a configuration of an I-I cross section of the one-component developing device.

FIG. 3 is a schematic perspective view showing an example of an agitating / conveying member used in the one-component developing device.

FIG. 4 is a schematic cross-sectional view showing the configuration of a conventional one-component developing device.

FIG. 5 is a diagram showing a planar configuration of the conventional one-component developing device.

FIG. 6 is a schematic perspective view showing an example of an agitating / conveying member used in the conventional one-component developing device.

FIG. 7 is a schematic cross-sectional view showing another example of a conventional one-component developing device.

FIG. 8 is a plan configuration diagram of the one-component developing device shown in FIG. 7.

[Explanation of symbols]

 1 Housing 2 Image Carrier 3 Developing Rolls 5 and 6 Toner Conveying Path 7 First Agitating and Conveying Member 8 Second Agitating and Conveying Member 9 Toner Supply Box

Claims (1)

[Claims] 1. A developing device used in an image forming apparatus that conveys one side edge of a sheet along a side guide member that is fixed and supported to transfer a toner image formed on an image carrier to the sheet. An apparatus, which is arranged opposite to the image bearing member, and which carries a one-component developer on its surface and conveys it, and both sides of which are arranged in parallel along this developing roller in the axial direction of the developing roller. Provided in the toner transport path on the side of the two toner transport paths adjacent to the developing roll of the two toner transport paths, and the toner is supplied from the side where the side guide member is not provided. A first agitating / conveying member that conveys to the side where the side guide member is provided, and a first agitating / conveying member that is provided in the other toner conveying path of the two toner conveying paths and is opposite to the first agitating and conveying member. Second direction to convey toner An agitating / conveying member; and a toner supplying unit for supplying toner to the inside of the toner conveying path provided with the second agitating and conveying member or to the upstream side of the toner conveying path provided with the first agitating and conveying member. Characteristic developing device.