JP2000338779A - One component developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a developing device where a stable image quality can be maintained over a long period of time by preventing generation of an abnormal image that may occur in the case of carrying out toner recycling in a one component developing device. SOLUTION: In this device, a toner layer restricting member 3 forming a thin toner layer on a toner carrier 2 is formed into an L shape that is bent at a bending part, this bent part is brought into contact with the toner carrier 2 or brought close to it and a free end is fixed by another end so that it is projected upstream in rotation of the toner carrier 2 against the bent part. Furthermore, this toner restricting member 3 is formed to be >=1 mm in length from the bent part to the free end and an angle formed by the bent part is formed to be greater than 60 deg. and less than 170 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus used for a copying machine, a printer, a facsimile, etc., for forming an image with a one-component developer composed of toner.

[0002]

2. Description of the Related Art In recent years, it has become an important issue to eliminate waste toner in order to cope with environmental problems. In particular, toner recycling has been actively performed in a two-component developing system. In the toner recycling, after the transfer process is completed, the toner on the electrostatic latent image holding body collected by the cleaning device is transported from the collection tank to the developing unit, and is used again for developing the electrostatic latent image on the image carrier. It is a mechanism to do. The one-component developing device is
Many are of the cartridge type and few are recycling toner. However, environmental issues, longer life and higher image quality have become important issues in single-component developing apparatuses, and in the future, toner recycling will be unavoidable even in single-component developing apparatuses. Usually, the one-component developing device includes a toner carrier for carrying toner and developing an electrostatic latent image on the electrostatic latent image carrier, a replenishing roller as a supply unit for supplying toner to the toner carrier, and a toner carrier. And a toner layer regulating member for forming a thin layer of toner on the toner carrier. The toner layer regulating member is brought into contact with the toner carrier at an appropriate pressure, and forms a thin layer of toner on the toner carrier as the toner carrier rotates. The contact pressure on the toner carrier is set in consideration of formation of a thin toner layer and toner charging. In order to form a stable image, it is important to form a uniform thin layer on the toner carrier, and the configuration of the toner layer regulating member and the mutual relationship between the toner carrier and the toner layer regulating member are extremely important. is there. As a known technique in which toner is recycled in a one-component developing device, a toner on an electrostatic latent image holding member after a toner image transfer process is collected without performing cleaning by a cleaning device to reduce waste toner. There are things that have realized.

The following techniques are known as toner recycling means. The first means is that after the transfer step, the toner on the electrostatic latent image holding member collected by the cleaning device pressed against the electrostatic latent image holding member is spirally conveyed from the toner collecting tank to a toner container or the like. The mechanism is used again for developing the electrostatic latent image on the electrostatic latent image holding member. The second means is to transport the toner on the electrostatic latent image holding member as it is to the position facing the toner holding member without cleaning the toner on the electrostatic latent image holding member after the transfer step. This is a mechanism to make the collection.

[0004]

However, when the toner is recycled, changes in the physical properties of the toner and deterioration of the image quality due to the inclusion of fibrous foreign matters become problems. Specific contents of the change in the physical properties of the toner include a decrease in the fluidity of the toner, a decrease in the chargeability of the toner, and an increase in the degree of aggregation of the toner. In the first means of the toner recycling, since the cleaning device is not used after the transfer process, a part of the fibrous foreign matter mixed in the toner on the electrostatic latent image holding member after the transfer process is partially removed. The toner is separated from the toner by the rotation of the electrostatic latent image holding member, and the frequency of occurrence of abnormal images due to fibrous foreign substances accompanying toner recycling decreases. This is because toner is charged particles and adheres to the electrostatic latent image holding member due to electrostatic force, but foreign matters such as paper dust are weakly charged particles, and the electrostatic movement is caused by the rotational movement of the electrostatic latent image holding member. This is because the holding power with the latent image holding member is reduced, and the paper dust is separated. However, in the second means of the toner recycling, the toner is collected in the collection tank by the cleaning device immediately after the transfer process. Will be returned.
Therefore, the amount of paper dust mixed increases. That is, in a one-component developing device that collects the toner on the electrostatic latent image holding member after the transfer process using a cleaning device and recycles the toner, it is inevitable that fibrous foreign matter is mixed. In addition, in the toner recycling by the one-component developing device, fibrous foreign matter is caught between the toner carrier and the toner layer regulating member to block the toner on the toner carrier,
The uniformity of the thickness of the toner layer is lost, and white stripes are generated on the image. Further, due to a change in physical properties of the toner, particularly, a decrease in the charge amount of the toner, toner adhesion (fogging) to an image background portion occurs.

Accordingly, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to prevent the occurrence of an abnormal image which can occur when toner is recycled in a one-component developing apparatus, and It is an object of the present invention to provide a developing device capable of maintaining stable image quality.

[0006]

According to a first aspect of the present invention, a toner carrier is disposed near an electrostatic latent image carrier, and the toner carrier is removed from a toner container. Supplying toner onto the body, forming a thin toner layer on the toner carrier by a toner layer forming member, developing the electrostatic latent image on the electrostatic latent image holding member, In the one-component developing device for collecting the toner remaining on the latent image holding member into the toner container, the toner layer regulating member is formed in an L-shape bent at a bent portion, and the bent portion is formed of the toner carrier. And is fixed at the other end so that the free end protrudes toward the rotation upstream side of the toner carrier with respect to the bent portion, and the length from the bent portion to the free end is 1 mm or more. And the fold Provided is a one-component developing device in which an angle formed by a bent portion is not less than 60 degrees and less than 170 degrees.

According to the invention described in claim 2, the bent portion of the toner layer regulating member facing the toner carrier has a round shape, and the radius of the round shape of the bent portion is 0.1 mm.
The one-component developing device according to claim 1, which is larger than 1 mm.

According to a third aspect of the present invention, a toner carrier is disposed near an electrostatic latent image carrier, toner is supplied from a toner storage container onto the toner carrier, and the toner is formed by a toner layer forming member. Forming a thin layer of toner on the carrier, developing the electrostatic latent image on the electrostatic latent image holding member, and removing the toner remaining on the electrostatic latent image holding member after the transferring step into the toner container. In a one-component developing device that collects
The toner layer regulating member has no bent portion, one end is in contact with or close to the toner carrier as a free end, and the other end is fixed to the free end on the downstream side of rotation of the toner carrier. The free end has a thickness of 1 mm or more, and an angle between a surface forming the thickness of the free end and a surface facing the toner carrier is 60 degrees or more and less than 170 degrees. A one-component developing device is provided.

According to a fourth aspect of the present invention, in the toner layer regulating member, a joint between a surface forming a thickness of the free end and a surface facing the toner carrier has a radius of 0.1 m.
The one-component developing device according to claim 3, wherein the one-component developing device has a round shape larger than m.

According to a fifth aspect of the present invention, a toner carrier is disposed near an electrostatic latent image carrier, toner is supplied from a toner container to the toner carrier, and the toner is formed by a toner layer forming member. Forming a thin layer of toner on the carrier, developing the electrostatic latent image on the electrostatic latent image holding member, and removing the toner remaining on the electrostatic latent image holding member after the transferring step into the toner container. In a one-component developing device that collects
The toner layer regulating member provides a one-component developing device having a cylindrical shape.

According to a sixth aspect of the present invention, in the toner layer regulating member, at least a surface close to the toner carrier is formed of a conductive member, and a bias having the same polarity as that of the toner is applied. A developing device according to claim 2, 3, 4, or 5 is provided.

According to a seventh aspect of the present invention, there is provided the one-component developing apparatus according to the sixth aspect, wherein a bias value applied to the toner layer regulating member is controlled based on a toner consumption determining means. .

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an embodiment of the one-component developing device according to the first embodiment, and a schematic enlarged view of a portion where a toner layer regulating member and a toner carrier are opposed to each other. In this developing device, a toner carrier 2 is disposed at an opening of a housing 5 facing the image carrier 1, is contacted in parallel with the image carrier 1, and is supported so as to rotate in the direction of the arrow.
On the upstream side of the developing area of the toner carrier 2 facing the image carrier 1, a toner conveying member 4 is disposed, and is supported so as to rotate in the opposite direction to the toner carrier 2. Also,
The toner layer regulating member 3 is disposed in contact with the toner carrier 2 on the downstream side of the portion facing the toner conveying member 4. The toner layer regulating member 3 is formed in an L-shape having a bent portion. After the bent portion contacts the surface of the toner carrier 2, one end of the toner layer regulating member 3 is connected to the housing 5 so that the free end is separated from the surface of the toner carrier 2. Fixed.

In this developing device, the toner in the toner container (not shown) is conveyed to the toner carrier 2 while being stirred by the rotation of the toner conveying member 4, and
Supplied above. The toner on the toner carrier 2 is conveyed by the rotation of the toner carrier 2 and the toner layer regulating member 3
A thin toner layer having a constant thickness is formed when passing through the contact portion with the toner. As shown in FIG. 1, the leading end of the toner layer regulating member 3 is bent into an L-shape, and the free end protrudes upstream in the rotation direction of the toner carrier 2. In the layer, before the L-shaped bent portion, a flow in the normal direction of the toner carrier 2 (in the direction of the arrow in the drawing) is formed, and the non-facing surface of the toner layer forming member 3 with the toner carrier 2 ( There is no toner flow on (A side in the figure). This prevents foreign matter from being caught between the toner layer regulating member 3 and the toner carrier 2. The formed toner thin layer is further transported to a development area facing the image carrier 1,
Used for developing the electrostatic latent image formed on the image carrier 1. The toner on the image carrier 1 not used for development is
The toner is collected by a cleaning device (not shown) pressed against the image carrier 1, conveyed to the toner storage unit, and used again for development.

On the other hand, as shown in FIG. 2, when the toner does not flow in the normal direction at the tip end of the toner layer regulating member 53, the toner carrier 52 of the toner layer regulating member 53
Is formed on the non-opposing surface (surface A in the figure). In this way, at the tip of the toner layer regulating member 53, a branch point (point B in FIG. 2) at which the toner flow is divided into two occurs, and fibrous foreign substances and the like are removed.
The phenomenon of being caught between the toner carrier 52 and the toner carrier 52 is likely to occur.
This is because the toner carrier 5 mixed in the recycled toner
When the foreign matter on the sheet 2 passes between the toner layer regulating member 53 and the tip of the fibrous foreign matter, the surface of the toner layer regulating member 53 facing the toner carrier 52 and the non-facing surface near the point B (see FIG. 2
(A side in the figure), which is likely to cause clogging.

The optimum shape of the toner layer regulating member 3 of the present embodiment is obtained from the following experiment. In a one-component developing device that performs toner recycling, the shape (folding length and bending angle) of the toner layer regulating member was changed, and a continuous image output experiment was performed. Fig. 5
(The distance from the plane B to the outer tip measured perpendicularly). The toner layer regulating member 13 in FIG. 5 has an upper portion as a fixed end, and a surface B is a surface facing the toner carrier (the toner carrier is omitted). Toner recycling was performed by transporting the toner collected by the cleaning device from the collection container to the toner container using a spiral. The toner layer regulating member 13 used is S
A US thin plate having a thickness of 0.1 mm and a free length of 10 mm was used. Here, the free length is the length from the free end side end of the toner layer regulating member of the member fixing the fixed end of the toner layer regulating member to the tip of the bent portion.

FIG. 3 summarizes the results obtained by changing the angle of the bent portion of the toner layer regulating member and examining the state of occurrence of white stripes on the entire halftone image, which is considered to be due to recycling. 3. In FIG. 3, .largecircle. Indicates that no white streaks were generated, .DELTA. Indicates that white streaks were slightly observed, and x indicates that white streaks occurred frequently. From these results, in the developing device of this embodiment, good results were obtained when the length of the bent portion of the toner layer regulating member was 1 mm or more, and the bending angle was improved when the angle of bending was 60 degrees or more. 17 bend angles
In the case of 0 degree, the toner layer regulating member has a linear shape, and the toner flow shown in FIG. 2 is generated, and foreign matter is likely to be clogged between the toner layer regulating member and the toner carrier. Therefore, the length of the bent portion of the tip portion of the toner layer regulating member is 1 mm or more, and the bent angle is 60 mm.
When the temperature is not less than 170 degrees and less than 170 degrees, a toner flow as shown in FIG. 1 is formed, foreign matter is less caught in the toner layer regulating member, and the level of white stripes is improved.

Next, in a one-component developing apparatus for performing toner recycling, the round shape of the bent portion of the toner layer regulating member was changed, and a continuous image output experiment was performed in the same manner as described above. The toner layer regulating member used had a bending length of 2 mm and a bending angle of 90 degrees. As a result, as shown in FIG. 4, by making the radius of the radius larger than 0.1 mm, the generation level of white stripes was improved. Since occurrence of an abnormal image was not confirmed when the radius of the radius is 0.3 mm or more, the radius of the radius is preferably 0.3 mm or more. Thus, the difference in the radius of the bent portion facing the toner carrier is the difference in the occurrence of white stripes. This is due to the toner stagnation area indicated by the black triangle in FIG. The toner stagnation region is formed gradually as the toner layer is thinned by the toner layer regulating member, and the toner adheres to the toner layer regulating member. Although the toner stagnation region exists regardless of the presence or absence of the radius at the tip, the bent portion has a round shape, so that the toner stagnation region becomes unstable, and a long-term stable image can be obtained. In the toner layer regulating member 43 having no round shape, the toner stagnation region is easily formed stably. When the toner stagnation region is formed, foreign matter and the like stagnate starting from the toner stagnation region, and thus an abnormal image is likely to occur. From the above experiment, FIG.
By using the toner layer regulating member 33 having the shape shown in FIG.
It can be seen that the clogging of foreign matters between the two is reduced, and the occurrence of an abnormal image can be prevented.

As for the shape of the bent portion of the toner layer regulating member, the same effect as the rounded toner layer regulating member shown in FIG. 5 can be obtained by chamfering the bent portion. In other words, the L-shaped corner of the toner layer regulating member is chamfered from a free end of the surface B by 0.1 mm or more, and preferably 0.3 mm or more away from the fixed end to eliminate the clogging of foreign matter. Can be.

Next, an embodiment of the one-component developing device according to the third aspect will be described. The structure of this developing device except for the toner layer regulating member is the same as that of the above-described embodiment shown in FIG. FIG. 6 is a sectional view of the toner layer regulating member of the developing device. The upper portion of the toner layer regulating member 23 has a fixed end similarly to the toner layer regulating member 13 shown in FIG.
The surface B is a surface facing the toner carrier (the toner carrier is omitted), and the surface C is a surface forming the thickness of the toner layer regulating member 23. The toner layer regulating member 23 has a shape without a bent portion as shown in FIG. 6, and the same effect as in the above embodiment can be obtained with a simple configuration.

Further, the shape of the toner layer regulating member may be a cylindrical shape as described in claim 5. Even when a cylindrical toner layer regulating member is used, the same effect as that of the toner layer regulating member having the bent portion in a round shape can be obtained. That is, the toner stagnation region becomes unstable, and a stable image can be obtained for a long period of time. Such a cylindrical toner layer regulating member may be pressed against and fixed to the toner carrier, or may be rotatably supported.

In the above-described embodiment, a bias is applied to the toner layer regulating member. This is because the toner chargeability of the recycled toner is reduced, and the recycled toner ratio (unused toner and recycled toner) is reduced. This is because, when the toner weight ratio is large, a sufficient charge amount cannot be obtained only by frictional charging when passing through the contact portion between the toner layer regulating member and the toner carrier. In addition, since the amount of recycled toner increases with toner consumption, the recycled toner rate can be changed based on the criterion for the amount of recycled toner consumption.
For example, it is based on the accumulated development drive time, the number of output sheets of transfer paper, the number of printed dots, and the like, and is not limited.

[0023]

As described above, the one-component developing apparatus of the present invention has the following effects. The one-component developing device according to claim 1, wherein in the one-component developing device that performs toner recycling, the shape of the toner layer regulating member is limited, so that fibrous foreign matter is located between the toner layer regulating member and the toner carrier. This reduces abnormal images caused by being sandwiched between the images, and makes it possible to obtain good images over a long period of time.

According to a second aspect of the present invention, in the one-component developing apparatus of the first aspect, the corner near the closest point between the toner layer regulating member and the toner carrier is rounded. By doing so, it is possible to suppress the occurrence of an abnormal image due to the fibrous foreign matter being caught between the toner layer regulating member and the toner carrier, and to obtain a good image over a long period of time.

According to a third aspect of the present invention, in the one-component developing apparatus for recycling toner, the shape of the toner layer regulating member is limited so that fibrous foreign matter can be transferred to the toner layer regulating member and the toner carrying member. An abnormal image generated by being sandwiched between the bodies is suppressed, and a good image can be obtained over a long period of time.

According to a fourth aspect of the present invention, in the one-component developing apparatus according to the third aspect, the corner near the closest point between the toner layer regulating member and the toner carrier is formed in a round shape. By doing so, it is possible to suppress the occurrence of an abnormal image due to the fibrous foreign matter being caught between the toner layer regulating member and the toner carrier, and to obtain a good image over a long period of time.

According to a fifth aspect of the present invention, in the one-component developing apparatus for recycling toner, the toner layer regulating member is formed in a cylindrical shape so that fibrous foreign matter is removed from the toner layer regulating member. It is possible to suppress the occurrence of an abnormal image caused by being sandwiched between the toner carriers, and to obtain a good image over a long period of time.

In the one-component developing apparatus according to the sixth aspect, the one-component developing apparatus according to the first, second, third, fourth, or fifth aspect of the present invention performs toner recycling. To prevent the occurrence of an abnormal image due to the decrease in the charge amount.

According to a seventh aspect of the present invention, in the one-component developing apparatus of the sixth aspect, the bias applied to the toner layer regulating member is changed in accordance with the ratio of the recycled toner. This makes it possible to always optimally charge the toner and to obtain a stable image for a long period of time.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an embodiment of a one-component developing device according to claim 1, and a schematic enlarged view illustrating a portion where a toner layer regulating member and a toner carrier are opposed to each other.

FIG. 2 is a diagram illustrating a facing portion between a toner layer regulating member and a toner carrier in a conventional developing device.

FIG. 3 is a diagram showing a result of an experiment for obtaining an angle condition of a bent portion of a toner layer regulating member used in the one-component developing device according to the first embodiment.

FIG. 4 is a view showing a result of an experiment for obtaining a radius condition of a radius shape of a toner layer regulating member used in the one-component developing device according to the first embodiment.

FIG. 5 is a schematic sectional view showing a toner layer regulating member used in the one-component developing device shown in FIG.

FIG. 6 is a schematic sectional view showing a toner layer regulating member used in an embodiment of the one-component developing device according to claim 2;

FIG. 7 is a diagram comparing the toner stagnation state when the toner layer regulating member used in the one-component developing device according to the first embodiment has a rounded shape at the bent portion and does not have the bent shape.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image carrier 2, 12, 32, 42, 52 Toner carrier 3, 13, 23, 33, 43, 53 Toner layer regulating member 4 Toner conveying member 5 Housing

Continued on the front page F term (reference) 2H077 AB15 AC04 AD02 AD06 AD13 AD17 AD22 AD31 AD35 AE03 AE10 BA03 DA15 EA11 FA25

Claims (7)

[Claims] 1. A toner carrier is disposed in the vicinity of an electrostatic latent image carrier, toner is supplied from a toner storage container onto the toner carrier, and a thin toner layer is formed on the toner carrier by a toner layer forming member. A one-component developing device that develops an electrostatic latent image on the electrostatic latent image holding member, and collects toner remaining on the electrostatic latent image holding member after the transferring step into the toner container. In the above, the toner layer regulating member may have a bent L at a bent portion.
The bent portion is fixed or fixed at another end so that the bent portion contacts or approaches the toner carrier, and the free end projects toward the rotation upstream side of the toner carrier with respect to the bent portion. A one-component developing apparatus, wherein a length from a bent portion to a free end has a length of 1 mm or more, and an angle formed by the bent portion is 60 degrees or more and less than 170 degrees. 2. The method according to claim 1, wherein a bent portion of the toner layer regulating member facing the toner carrier forms a round shape, and a radius of the round shape of the bent portion is larger than 0.1 mm. The one-component developing device according to claim 1. 3. A toner carrier is disposed in the vicinity of the electrostatic latent image carrier, toner is supplied from the toner container onto the toner carrier, and a toner layer forming member forms a thin toner layer on the toner carrier. A one-component developing device that develops an electrostatic latent image on the electrostatic latent image holding member, and collects toner remaining on the electrostatic latent image holding member after the transferring step into the toner container. In the above, the toner layer regulating member does not have a bent portion, and one end is in contact with or close to the toner carrier as a free end, and the other end is on the downstream side of rotation of the toner carrier with respect to the free end. The free end has a thickness of 1 mm or more at the end of the free end, and the angle between the surface forming the thickness of the free end and the surface facing the toner carrier is 60 degrees or more and less than 170 degrees. One-component developing device 4. The toner layer regulating member according to claim 1, wherein a joining portion between a surface forming the thickness of the end of the free end and a surface facing the toner carrier forms an R shape having a radius larger than 0.1 mm. The one-component developing device according to claim 3, wherein: 5. A toner carrier is disposed in the vicinity of an electrostatic latent image carrier, toner is supplied from a toner container to the toner carrier, and a thin toner layer is formed on the toner carrier by a toner layer forming member. A one-component developing device that develops an electrostatic latent image on the electrostatic latent image holding member, and collects toner remaining on the electrostatic latent image holding member after the transferring step into the toner container. 3. The one-component developing device according to claim 1, wherein the toner layer regulating member has a cylindrical shape. 6. The toner layer regulating member has at least a surface close to the toner carrier made of a conductive material,
The developing device according to claim 1, wherein a bias having the same polarity as that of the toner is applied. 7. The one-component developing apparatus according to claim 6, wherein the bias value applied to the toner layer regulating member is controlled based on a toner consumption determining unit.