JP4428088B2 - Developing device and image forming apparatus using the same - Google Patents

Description

  The present invention relates to a developing device used in an image forming apparatus such as a copying machine or a printer, and more particularly to a developing device using a non-magnetic one-component developer and an image forming apparatus using the developing device.

  Development devices used in conventional image forming apparatuses such as an electrophotographic system include a non-magnetic one-component development method using a non-magnetic one-component developer (toner) composed only of toner and a two-component development composed of toner and a carrier. A two-component development system using an agent is known. In particular, the non-magnetic one-component developing type developing device does not require mixing with the carrier, stirring, and toner concentration control, so the size of the device can be reduced and the cost can be reduced, and the developer can be replaced. Is unnecessary, and is increasingly used mainly in printers that require maintenance-free operation.

JP-A-8-179608 (column of Example 1, FIG. 1) JP-A-9-62088 (column of embodiment of the invention, FIG. 3) Japanese Patent Application Laid-Open No. 7-234583 (Example column, FIG. 1)

In the non-magnetic one-component development system, how to form a toner layer having a predetermined toner amount and toner charge amount on the developing roll is an important factor. For this reason, usually, after a certain amount of toner has adhered to the developing roll while a toner supply roll using a foam bite into the developing roll, the toner on the developing roll is regulated by a regulating blade provided on the developing roll side. A method of layer thickness regulation and charging (charging adjustment) is employed.
However, in this method, the toner is subject to mechanical stress in the nip area between the toner supply roll and the developing roll and the nip area between the developing roll and the regulating blade, and the toner is liable to be deteriorated. There is a problem that heat is generated by pressure for regulating the thickness, and toner sticks to the regulating blade. In particular, in a developing device used for an image forming apparatus for forming a color image, it is necessary to develop a color image by completely melting each color toner in order to form a color image. There is a tendency to lower the melting point of the resin, and sticking to the regulating blade tends to occur more easily.

In order to solve such a problem, a system in which a developing roll and a toner supply roll are disposed apart from each other has been proposed (see, for example, Patent Documents 1 to 3).
In Patent Document 1, an example in which a developing roll and a toner supply roll are spaced apart and a regular polygonal column-shaped roll of the toner supply roll is used is presented. Japanese Patent Application Laid-Open No. 2004-228561 proposes a configuration in which a toner collection roll is provided in addition to the toner supply roll. Furthermore, Patent Document 3 discloses an appropriate gap between the developing roll and the toner supply roll.
In particular, in Patent Document 3, as shown in FIG. 13, the relationship between the gap m between the developing roll 51 and the toner supply roll 52 and the toner layer thickness n on the developing roll 51 is set such that m ≧ n. Has been.

  However, in these techniques, as shown in FIG. 13, since the developing roll 51 and the toner supply roll 52 are spaced apart from each other, the toner stress in the nip area between the two is reduced. In any method, a member such as a layer thickness regulating blade 53 is provided on the developing roll 51 side. Further, excess toner adheres on the upstream side of the layer thickness regulating blade 53, and the excess toner is scraped off by the layer thickness regulating blade 53, and at the same time, charge adjustment to the toner is performed. For this reason, it is necessary to apply the layer thickness regulating blade 53 to the developing roll 51 to some extent (increase the pressure contact force), and problems of toner adhesion to the layer thickness regulating blade 53 and toner stress remain unresolved. The structure is not suitable for extending the service life.

  The present invention has been made in order to solve the above technical problem, and further makes the toner amount and the toner charge amount of the developer layer formed on the developer carrier more uniform, and further, over a long period of time. And a developing device having stable development characteristics and an image forming apparatus using the same.

That is, the present invention, as shown in FIG. 1, is a developer carrying body 2 that faces the image carrying body 1 carrying an electrostatic latent image and is rotatable and carries a nonmagnetic one-component developer on its surface, A developer supply member 4 that is spaced apart from the developer carrier 2 and is rotatable and carries and transports a non-magnetic one-component developer on its surface is provided between the developer carrier 4 and the developer carrier 2. A supply electric field for supplying a non-magnetic one-component developer from the developer supply member 4 to the developer carrier 2 is applied to the developer carrier member 4 while regulating the amount of developer on the developer carrier 2 with the developer supply member 4. The regulation supply means 3 for supplying the non-magnetic one-component developer to the developer carrier 2 and the regulation supply means 3 disposed opposite to the developer carrier 2 on the downstream side of the regulation supply means 3. And a charge adjusting member 5 for adjusting the charge of the regulated developer layer. It is intended.

In such technical means, the developing device according to the present application uses a non-magnetic one-component developer (developer), and the developer carrier 2 may be any drum as long as it can carry the developer. Shape, including belt shape. Further, from the viewpoint of effective development, an embodiment in which the developer carrying member 2 is arranged in contact with the image carrying member 1 is preferable, but it may be non-contact. Further, the developer carrier 2 may be an elastic body or a rigid body.
Further, the developer supply member 4 preferably has a foam structure from the viewpoint of carrying and transporting the developer, but is not particularly limited as long as it can carry and carry the developer.
Further, the rotation direction of the developer carrier 2 and the developer supply member 4 may be the same direction (With direction) or a different direction (Against direction) at the opposite portions.

Then, the regulated supply means 3 in the present invention supplies the developer whose layer thickness is regulated to the developer carrier 2, so that the regulated developer is charged on the developer carrier 2 for charge adjustment. The adjustment member 5 may be provided. Therefore, it is characterized in that a layer thickness regulating member that is disposed on the developer carrier 2 in the prior art and that regulates the layer thickness of the developer and imparts charging is not necessary.
At this time, the regulation supply means 3 only needs to have a developer supply function and a developer layer thickness regulation function. For example, the gap between the developer carrier 2 and the developer supply member 4, the developer carrier 2 is adjusted by a supply electric field 6 applied between the developer supply member 4 and the developer supply member 4. It should be noted that the developer supply function of the regulation supply means 3 is not limited, but is usually low.
In addition, as the charge adjusting member 5, charge adjustment (friction charging) is performed with a weak pressure corresponding to a predetermined developer layer thickness with respect to the developer whose layer thickness is controlled supplied on the developer carrier 2. You just have to do it. Although the developer layer thickness is hardly regulated by the charge adjustment member 5, fine adjustment can be performed because the charge adjustment member 5 is in contact with the developer carrier 2. Furthermore, the charge adjusting member 5 may be in the form of a blade or a roll.

  As a first aspect of the regulation supply means 3 in the present invention, the supply of the developer from the developer supply member 4 to the developer support 2 is provided between the developer support 2 and the developer supply member 4. An electric field 6 is applied, and the developer carrier 2 and the developer supply member 4 are rotated in the same direction at the opposing portions, and the developer carrier 2 is further on the developer carrier 2 on the developer supply member 4. The point arrange | positioned above the tangent which passes along the nearest point to is mentioned. This makes it difficult for the developer blown off at the downstream side of the nip area between the developer carrier 2 and the developer supply member 4 to adhere to the developer carrier 2 side, and the amount of developer on the developer carrier 2 is stable. To do.

In this embodiment, the developer supply efficiency from the developer supply member 4 to the developer carrier 2 is improved by making the peripheral speed of the developer supply member 4 larger than the peripheral speed of the developer carrier 2. Therefore, the supply efficiency is further improved by setting the peripheral speed of the developer supply member 4 to 1.5 times or more the peripheral speed of the developer carrier 2.
Furthermore, in this aspect, the developer supplied from the developer supply member 4 to the developer carrier 2 by applying a DC voltage in which an AC voltage is superimposed between the developer carrier 2 and the developer supply member 4. It becomes easier to control the amount.
Furthermore, by providing a cleaning member on the downstream side of the nip region of the developer supply member 4, the developer on the developer supply member 4 is removed, and a supply electric field 6 between the developer carrier 2 and the developer supply member 4. Is preferable because it becomes constant. In addition, it is preferable that the developer carrier 2 is also provided with a peeling member because the supply electric field 6 applied to the developer is further stabilized.

  On the other hand, as a second aspect of the regulation supply means 3 in the present invention, the supply of the developer from the developer supply member 4 to the developer support 2 is provided between the developer support 2 and the developer supply member 4. The electric field 6 is applied, and the developer carrier 2 and the developer supply member 4 are rotated in different directions at the opposite portions of the two, and further, the developer developer 2 is prevented from adhering to the surface of the developer carrier 2. The point which arrange | positions an adhesion prevention means is mentioned. In the case where the developer carrier 2 and the developer supply member 4 have the Gainst configuration, the developer inevitably accumulates on the downstream side of the nip region of the developer supply member 4. In this aspect, by providing a separate adhesion preventing means, it is intended to prevent the excessive developer from adhering to the developer carrier 2 due to the accumulation described above.

Also in this embodiment, as in the first embodiment, the developer carrying member 4 and the developer supplying member 4 are applied with a DC voltage in which an AC voltage is superimposed, whereby the developer carrying member 4 carries the developer carrying member. It becomes easier to control the amount of developer supplied to the body 2.
Further, as the adhesion preventing means in this embodiment, the developer carrier 2 and the developer are prevented so that the developer accumulation is suppressed on the developer supply member 4 side so that excessive developer does not flow to the developer carrier 2 side. There is a configuration in which the adhesion regulating member is disposed in a position close to the portion facing the supply member 4 and separated from the developer carrier 2 and the developer supply member 4.
Further, as another adhesion preventing means, there is provided a regulating member that is disposed opposite to the developer supply member 4 and regulates the developer transport amount on the developer supply member 4 so that the developer carrier 2 and the developer supply are provided. A configuration in which a developer pool is not formed on the upstream side of the nip region with the member 4 can be given.
As an aspect of the image forming apparatus according to the present invention, the above-described developing device is provided as an image carrier 1 that carries an electrostatic latent image and a developing device that develops the electrostatic latent image on the image carrier 1. It is characterized by that.

According to the developing device of the present invention, a non-magnetic one-component developer is used, the developer carrier and the developer supply member are spaced apart from each other, and the non-magnetic component is provided between the developer supply member and the developer carrier. Apply a supply electric field to supply a one-component developer from the developer supply member to the developer carrier, regulate the layer thickness when supplying the developer from the developer supply member to the developer carrier, and adjust the charge after regulating the layer thickness Therefore, it is possible to provide a charge adjusting member having a small pressure contact force with respect to the non-magnetic one-component developer, and to obtain a developing characteristic in which stress on the developer is small and adhesion of the developer is suppressed. it can.
Further, by using these developing devices, it is possible to easily construct an image forming apparatus capable of stable image formation over a long period of time.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
Embodiment 1
FIG. 2 shows an image forming apparatus according to the first embodiment to which the present invention is applied.
In the figure, reference numeral 21 denotes a photosensitive member that carries an electrostatic latent image made of an organic photosensitive member that rotates in the direction of an arrow. The photosensitive member 21 is charged by a charging device 22 such as a scorotron, and a laser writing device or LED. An electrostatic latent image is written by the exposure device 23 having an array. The written electrostatic latent image is formed as a potential image based on contrast with a high potential portion not exposed to light because the surface potential of the photosensitive member 21 exposed to light decreases.
Further, the developing device 30 accommodates toner, which is a non-magnetic one-component developer, in a developing housing 31 and carries the toner on a developing roll 32 as a developer carrying member. By applying the developing bias, the developing roll 32 is held at an intermediate potential between the high potential portion and the low potential portion of the electrostatic latent image, and the image portion of the electrostatic latent image is developed with the charged toner. It is a thing.
Further, a toner supply roll 34 for supplying toner to the development roll 32 is disposed behind the development roll 32 at a position separated from the development roll 32, and the bias power source 35 connected to the toner supply roll 34 and the development are provided. The developer is supplied from the toner supply roll 34 to the developing roll 32 by an electric field formed by the bias power supply 33 on the roll 32 side.
Further, the transfer device 26 is constituted by, for example, a transfer roll disposed in contact with the photoconductor 21, and applies a transfer bias in a direction in which the toner image on the photoconductor 21 is attracted by the bias power source 27, thereby causing the photoconductor 21 to be applied. The upper toner image is transferred to the recording material 28.
The toner remaining on the photoreceptor 21 is removed by, for example, a doctor blade type cleaning device 29.

In this embodiment, the recording material 28 to which the toner image on the photosensitive member 21 is transferred is conveyed to the fixing device 50, and the toner image is fixed to the recording material 28 by the fixing device 50.
The fixing device 50 has, for example, a heat roll method, and includes a heating roll 51 and a pressure roll 52. By passing the recording material 28 between the heating roll 51 and the pressure roll 52, the toner image is recorded. 28 is fixed.

Here, the developing device 30, which is a feature of the present invention, will be described in detail with reference to FIGS. In the drawing, the developing device 30 has a developing housing 31 that opens toward the photosensitive member 21, and a developing roll 32 is provided at a position facing the opening of the developing housing 31 and facing the photosensitive member 21. It is housed in a rotatable manner.
In the present embodiment, the developing roll 32 has a configuration in which the outer periphery of a metal roll made of, for example, aluminum or stainless steel is coated with a semiconductive rubber made of urethane rubber or silicone rubber. It doesn't matter.

Behind the developing roll 32 is disposed a toner supply roll 34 made of an elastic foam that is spaced apart from the developing roll 32 and supplies toner as a developer to the developing roll 32. The developing roll 32 and the toner supply roll 34 is configured so as to rotate in the same direction (with direction) at the opposite part of both.
The toner supply roll 34 may be any as long as it can supply toner to the developing roll 32, and may be in the form of a roll, a belt, or a brush.
In the present embodiment, the developing roll 32 and the toner supply roll 34 are, as shown in FIG. 4, the developing roll 32 above the tangent line s passing through the closest point to the developing roll 32 on the toner supply roll 34. Are arranged, and the gap between the two is 100 μm. Further, the peripheral speed of the toner supply roll 34 is made larger than the peripheral speed of the developing roll 32, and the ratio is set to 1.5.
As shown in FIG. 3, a toner hopper 36 for storing toner is provided behind the toner supply roll 34, and the toner is agitated by an agitator 37. The shaft 37a of the agitator 37 is made of resin, and the blade 37b for agitating the toner is made of a resin sheet such as a PET sheet. The agitator 37 agitates the toner in the toner hopper 36 and supplies toner to the toner supply roll 34 side. It comes to supply.

At a position facing the developing roll 32, a charge adjusting member 38 that adjusts the charging of the toner on the developing roll 32 is fixed to the developing housing 31 at the downstream side of the nip region between the developing roll 32 and the toner supply roll 34. It is supported. In the present embodiment, the charge adjusting member 38 uses, for example, a 0.05 mmt SUS plate, and the contact pressure with respect to the developing roll 32 is set to be extremely small. For this reason, there is no deformation of the developing roll 32, and the toner is not fixed to the charge adjusting member 38. In the present embodiment, an SUS plate is used as the charge adjustment member 38, but other metal such as phosphor bronze may be used, or a metal coated with a resin coating such as urethane rubber may be used. May be used.
Further, at a position facing the developing roll 32, a peeling member 39 that peels off the toner that has not been consumed in the development is disposed on the downstream side of the developing area that is a portion facing the photoreceptor 21. As the peeling member 39, a PET resin plate is used, but a metal plate or the like may be used.

Further, a peeling blade 40 is provided at a position facing the toner supply roll 34 to peel the toner on the toner supply roll 34 so that the supply electric field between the developing roll 32 and the toner supply roll 34 becomes constant. It is installed.
The toner peeled off from the toner supply roll 34 by the peeling blade 40 is combined with the toner discharged from the nip region between the developing roll 32 and the toner supply roll 34, and the toner supply roll 34 and the development housing 31 are connected to each other. It falls into the gap and is returned to the toner hopper 36 through the paddle 41. The paddle 41 includes a blade made of a PET resin plate, and is configured to return the toner to the toner hopper 36 by this rotation.

  Further, in the present embodiment, the toner blown from the nip region between the developing roll 32 and the toner supply roll 34 is reflected by the wall surface of the developing housing 31 so that excessive toner does not adhere to the developing roll 32. The distance from the nip region to the wall surface is 15 mm or more, and the angle of the wall surface (α region) where the blown-out toner hits is 60 ° or more from the horizontal plane.

Next, the operation of the developing device 30 according to the present embodiment will be described with reference to FIG.
In the drawing, the toner stirred by the agitator 37 in the toner hopper 36 is supplied to the toner supply roll 34 side by the blades 37 b of the agitator 37. The toner supplied to the toner supply roll 34 forms a toner pool upstream of the nip area between the developing roll 32 and the toner supply roll 34, and the toner in the toner pool is transferred between the developing roll 32 and the toner supply roll 34. With rotation, it is conveyed downstream through both nip areas.
At this time, in this embodiment, a DC voltage on which an AC voltage is superimposed is applied as a supply electric field between the developing roll 32 and the toner supply roll 34. Further, since the peripheral speed of the toner supply roll 34 is 1.5 times the peripheral speed of the developing roll 32, predetermined toner adheres to the developing roll 32, and toner blown out from the nip area is also removed from the developing roll. The toner amount on the developing roll 32 is stabilized without going to the side 32.
The toner supplied with the layer thickness regulated on the developing roll 32 is charged to a predetermined charge amount by the subsequent charge adjusting member 38, conveyed on the developing roll 32, and developed with the photoreceptor 21 (see FIG. 2). It is subjected to development in the area. The toner that has not been consumed in the development is peeled off from the surface of the developing roll 32 by the peeling member 39 disposed further downstream. The toner peeled here is returned to the above-described toner accumulation direction with the peeling member 39 as a guide.

  On the other hand, the toner peeled off from the toner supply roll 34 by the peeling blade 40 falls in the developing housing 31 toward the paddle 41 in the same manner as the toner blown from the nip region between the developing roll 32 and the toner supply roll 34. The paddle 41 is returned to the toner hopper 36 as the paddle 41 rotates.

In the present embodiment, the toner layer thickness on the developing roll 32 is stable because the layer thickness is once regulated and the toner supplied to the developing roll 32 does not adhere to the toner. Since only the adjustment is performed, the load on the developing roll 32 by the charge adjusting member 38 is small, and the developing roll 32 can be prevented from being deteriorated, and at the same time, development without applying stress to the toner is possible. In addition, since the toner supply roll 34 and the developing roll 32 are provided with peeling members (specifically, the peeling blade 40 and the peeling member 39), the supply electric field between the developing roll 32 and the toner supply roll 34 is further stabilized. In addition, the amount of toner supplied to the developing roll 32 can be further stabilized. Further, since the toner adhesion amount can be controlled by the supply electric field, the image density can be adjusted and stabilized.
Accordingly, it is possible to ensure the uniformity of toner supply to the developing roll 32 and to suppress fluctuations in toner supply conditions even for long-term use.

  In the present embodiment, a metal blade is used as the charge adjustment member 38. However, the charge adjustment member 38 in this case does not require a regulating force for the toner layer thickness. It is also possible to use a member having a smaller linear pressure than the blade.

Embodiment 2
FIG. 5 shows a main part of the developing device 30 according to the second embodiment to which the present invention is applied. In this figure, the present embodiment is configured in substantially the same manner as the developing device 30 in the first embodiment, except that the rotation directions of the developing roll 32 and the toner supply roll 34 are different, and the toner hopper 36 in the developing housing 31. The present embodiment is different from the first embodiment in that a partition wall 42 for partitioning the developing chamber 49 is provided. In the present embodiment, a large amount of toner can be stacked.
Therefore, in this embodiment, two agitators 37 and 43 are provided in the toner hopper 36. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and the detailed description is abbreviate | omitted.

Also in the present embodiment, as in the first embodiment, as shown in FIG. 6, the developing roll 32 and the toner supply roll 34 are arranged, and the developing roll 32 is placed above the tangent s of the toner supply roll 34. It is arranged. Furthermore, in the present embodiment, when the angle formed by the tangent s and the vertical line is θ, θ is 10 ° or more. And the partition wall 42 is installed in the position of 15 mm or more of the extension direction of both nip area | regions. For this reason, the toner blown out from the nip area does not cause excessive toner adhesion to the developing roll 32 side.
Further, in the present embodiment, as shown in FIG. 5, the developing roll 32 is provided with the charge adjusting member 38, but is not particularly provided with the peeling member as in the first embodiment. On the other hand, the toner supply roll 34 is provided with a peeling blade 40.
In particular, in the present embodiment, since toner is supplied from below the toner supply roll 34, the toner supply path 44 toward the nip region between the toner supply roll 34 and the developing roll 32 is on the downstream side. It becomes narrower. Therefore, as the toner supply roll 34 rotates, the toner is more reliably conveyed to the nip area without creating a toner reservoir in the toner supply path 44.
In addition, a stirring bar 45 is provided near the upstream inlet of the toner supply path 44 so that the toner is supplied to the toner supply path 44. By rotating the stirring bar 45, the toner at this portion is supplied. Accumulation is prevented and the toner flows into the toner supply path 44.

For this reason, the present embodiment has the same effects as those of the first embodiment. Further, in the present embodiment, since the toner to be blown out from the nip area is provided at the upper side, the developing device 30 can be made thinner than the structure in which the space to be blown out is provided on the lower side as in the first embodiment.
The stirring bar 45 in the present embodiment is not a mode in which the toner is stirred in the axial direction but may be stirred in the rotation direction, and therefore, for example, a metal bar having irregularities on the surface is used.

  Further, as a modification of the present embodiment, as shown in FIG. 7, the toner blown from the nip region between the developing roll 32 and the toner supply roll 34 toward the partition wall 42 is made with a hole 46 in the partition wall 42. If the toner is collected directly on the toner hopper 36 side, the partition wall 42 can be brought closer to the developing roll 32 side. Therefore, the developing chamber 49 can be narrowed, and a smaller developing device 30 is possible. In FIG. 7, a bias power source and a stirring bar are omitted.

Embodiment 3
FIG. 8 shows a main part of the developing device 30 according to the third embodiment to which the present invention is applied. In this figure, in the present embodiment, unlike the first and second embodiments, the developing roll 32 and the toner supply roll 34 are rotated in opposite directions (Against direction) at the opposite portions. Further, in the present embodiment, the adhesion regulating member 47 is provided so that the toner reservoir β formed in the upstream area of the toner supply roll 34 in the nip area between the development roll 32 and the toner supply roll 34 does not contact the development roll 32. It has. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and the detailed description is abbreviate | omitted.

  In the present embodiment, the toner supplied to the developing roll 32 side in the nip area between the developing roll 32 and the toner supply roll 34 exceeds the nip area without the toner in the toner pool β adhering to the surface. The toner layer on the developing roll 32 has a predetermined amount. For this reason, only the charge adjustment is performed by the charge adjusting member 38 disposed opposite to the downstream side of the developing roll 32, so that the charging adjusting member 38 only needs to be applied to the developing roll 32 with a weak pressure. Therefore, the same effects as those of the first embodiment can be obtained.

  At this time, in the case where the adhesion regulating member 47 as shown in FIG. 9 is not provided, the toner in the toner reservoir β is placed on the developing roll 32 beyond the nip area between the developing roll 32 and the toner supply roll 34. The charge adjusting member 38 needs to have both the toner layer thickness regulation on the developing roll 32 and the charge adjusting function. For this reason, it is necessary to strongly apply the charge adjusting member 38 to the developing roll 32, which causes deterioration of the developing roll 32 and stress on the toner. Therefore, the superiority in the configuration including the adhesion regulating member 47 as in the present embodiment is obvious.

Embodiment 4
FIG. 10 shows a main part of the developing device 30 according to the fourth embodiment to which the present invention is applied. In this figure, in the present embodiment, a developing roll 32 and a toner supply roll 34 are rotated in opposite directions (Against direction) at opposite portions of each other as in the third embodiment. Further, in the present embodiment, a regulating member 48 made of, for example, an aluminum plate, which is spaced from the toner supply roll 34 on the upstream side of the toner supply roll 34 in the nip region between the developing roll 32 and the toner supply roll 34. It has. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and the detailed description is abbreviate | omitted.

In the figure, toner supplied from a toner hopper (not shown) to the toner supply roll 34 is regulated by the regulating member 48 so that the toner supply amount on the toner supply roll 34 is regulated. Only the quantity is transported.
Then, only this predetermined amount of toner is conveyed to the nip area, so that no toner pool is formed on the upstream side of the toner supply roll 34 in the nip area, and the toner is regenerated on the developing roll 32 beyond the nip area. There is no adhesion. Therefore, the present embodiment has the same effect as the first embodiment.

Example 1
In this example, the relationship between the bias difference between the developing roll and the toner supply roll and the toner adhesion amount on the developing roll in the configuration of the first embodiment (see FIG. 3) was evaluated and confirmed. The gap between the developing roll and the toner supply roll was 50 μm and 200 μm.
In this embodiment, as the supply bias between the developing roll and the toner supply roll, the AC voltage was 2 kHz and 1 kVpp, and the DC voltage _VDC was superimposed thereon. The used toner is negatively charged toner.
As a result, as shown in FIG. 11, in the region where the DC voltage _VDC is −40 V to +200 V (the developing roll side is positive), the toner adhesion amount tends to increase almost linearly regardless of the size of the gap. It was. Further, when the gap was 50 μm and 200 μm, the former tended to have a slightly larger amount of adhesion.
Therefore, by adjusting the supply bias between the developing roll and the toner supply roll (specifically, by adjusting the DC voltage _VDC of the supply bias), a predetermined amount of toner can be adhered to the developing roll. It was confirmed that Therefore, it is possible to adjust and stabilize the image density by adjusting the supply bias.

  In this example, the gap between the developing roll and the toner supply roll was evaluated as 50 μm and 200 μm. However, if the gap is about 50 μm, the thickness of the toner layer adhering to the developing roll is limited, and the effect of the supplied electric field is clear. It becomes difficult to appear in. Further, when this gap exceeds 200 μm, there is a concern that the supply electric field is strengthened or the toner layer thickness on the developing roll becomes thick, and the practical gap is determined to be about 200 μm.

Example 2
Similarly to Example 1, this example is also performed by the configuration of Embodiment 1 (see FIG. 3), and the peripheral speed ratio of the developing roll to the toner supply roll (toner supply roll peripheral speed / developing roll peripheral speed) This is an evaluation and confirmation of the toner adhesion amount on the developing roll.
In this embodiment, the gap between the developing roll and the toner supply roll was 100 μm, the supply bias was 40 VDC, the alternating voltage was 2 kHz, and 1.6 kVpp.
As a result, as shown in FIG. 12, a substantially constant toner adhesion amount was obtained at a peripheral speed ratio of 1.5 to 6. From this, the toner adhesion amount to the developing roll is mainly influenced by the supplied electric field, and if the peripheral speed ratio is 1.5 or more, a sufficient amount of toner passes between the gaps, and a stable toner adhesion amount can be obtained. confirmed.

It is explanatory drawing which shows the outline | summary of the image development apparatus concerning this invention. 1 is an explanatory diagram showing Embodiment 1 of an image forming apparatus to which the present invention is applied. FIG. 2 is an explanatory diagram illustrating a developing device according to the first embodiment. FIG. 2 is an enlarged view of a main part of the developing device according to the first embodiment. FIG. 10 is an explanatory diagram illustrating a developing device according to a second embodiment. FIG. 6 is an enlarged view of a main part of the second embodiment. 10 is an explanatory diagram showing a modification of the second embodiment. FIG. FIG. 10 is an enlarged view of a main part of a developing device according to a third embodiment. FIG. 10 is an explanatory diagram illustrating a comparative example of the third embodiment. FIG. 10 is an explanatory diagram illustrating a developing device according to a fourth embodiment. 3 is a graph showing the results of Example 1. 10 is a graph showing the results of Example 2. It is explanatory drawing which shows the developing device as a prior art example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image carrier, 2 ... Developer carrier, 3 ... Regulation supply means, 4 ... Developer supply member, 5 ... Charge adjustment member, 6 ... Supply electric field

Claims (11)

A developer carrying member that faces the image bearing member carrying the electrostatic latent image and is rotatable and carries a non-magnetic one-component developer on the surface;
The developer carrying member has a developer supply member that is spaced apart from the developer carrying member and is rotatable and carries a non-magnetic one-component developer on the surface. The non-magnetic member is provided between the developer carrying member and the developer carrying member. the one-component developer is applied to supply an electric field supplied from the developer supply member to the developer bearing member, the non-contrast developer carrying member while regulating the amount of developer on the developer carrying member in the developing agent supplying member Regulation supply means for supplying magnetic one-component developer;
A developing device comprising: a charge adjusting member disposed on the downstream side of the regulation supply means so as to face the developer carrying member and for adjusting the charge of the developer layer regulated and supplied by the regulation supply means. . The developing device according to claim 1,
Regulating supply means, and a developer supplying member and the developer carrying member is rotated in the same direction in both opposing part, further the developer carrying member passes through the closest point to the developer carrying member of the developing agent supplying member A developing device arranged above a tangent line. The developing device according to claim 2, wherein
A developing device characterized in that the peripheral speed of the developer supply member is made larger than the peripheral speed of the developer carrier. The developing device according to claim 2, wherein
A developing device, wherein a supply electric field applied between a developer carrying member and a developer supply member is a DC voltage on which an AC voltage is superimposed. The developing device according to claim 2, wherein
The regulation supply means is disposed opposite to the developer supply member on the downstream side of the facing portion between the developer carrier on the developer supply member and the developer supply member, and removes the developer on the developer supply member. A developing device comprising a cleaning member. The developing device according to claim 5, wherein
The regulation supply means is further disposed on the upstream side of the opposed portion of the developer carrier on the developer carrier and the developer supply member so as to face the developer carrier, and the developer on the developer carrier. A developing device comprising a peeling member for peeling. The developing device according to claim 1,
Regulating the supply means includes a developer carrying member and a developer supplying member is rotated in different directions in both opposing part, further the adhesion prevention means for preventing the excessive developer to the developer carrying member surface adheres A developing device provided. The developing device according to claim 7.
A developing device, wherein a supply electric field applied between a developer carrying member and a developer supply member is a DC voltage on which an AC voltage is superimposed. The developing device according to claim 7.
The adhesion preventing means is an adhesion regulating member disposed in a position close to a facing portion between the developer carrier and the developer supply member and spaced from the developer carrier and the developer supply member. Development device. The developing device according to claim 7.
The developing device according to claim 1, wherein the adhesion preventing means is a regulating member that is disposed to face the developer supply member and regulates a developer conveyance amount on the developer supply member. An image carrier for carrying an electrostatic latent image;
An image forming apparatus comprising: the developing device according to claim 1, which develops an electrostatic latent image on the image carrier.

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