JPH0411869B2 - - Google Patents

Description

Detailed Description of the Invention <Technical Field> The present invention relates to an electrostatic latent image developing device used in an electrostatic copying machine or the like to apply toner particles to an electrostatic latent image to make it a developed image. relates to an electrostatic latent image developing device of the type that uses a one-component developer consisting only of toner particles capable of retaining an electric charge.

<Prior art and its problems> Electrostatic latent image developing devices used in electrostatic copying machines and the like to apply toner to an electrostatic latent image to make it a visible image can be roughly divided into carrier particles and toner particles. There are two types of devices: those that use a so-called two-component developer, and those that use a one-component developer that consists only of toner particles. In order to stably perform good development, the ratio of carrier particles to toner particles must always be maintained at the required value, and therefore, depending on the consumption of toner particles due to the performance of development, There are difficult problems to solve, such as the need to properly replenish toner particles. Therefore, in recent years, there has been a tendency to advantageously use electrostatic latent image developing devices that use a one-component developer.

Therefore, depending on the characteristics of the one-component developer used, an electrostatic latent image developing device that uses a one-component developer is capable of developing (a) a one-component developer consisting only of relatively conductive toner particles; (b) devices that use a one-component developer consisting only of relatively insulating toner particles;

Apparatuses and methods using the above developer (a) are described, for example, in Japanese Patent Publication No. 37-491, Japanese Patent Publication No. 37-492, Japanese Patent Publication No. 20695-1982, Japanese Patent Application Laid-Open No. 49-5035, It is disclosed in known documents such as the specification and drawings of Patent No. 2976144, the specification and drawings of US Pat. No. 3,909,258, and the specification and drawings of US Patent No. 4,081,571. As is clear from such known documents, when using the developer described in (a) above, the developer is held on the surface of the developer holding member and transported to the development area to form an electrostatic latent image. Only contact is required to cause the developer to adhere to the electrostatic latent image as desired; therefore, no special treatment, such as charging the developer, is required prior to contacting the electrostatic latent image. The advantage is that it doesn't. However, since the toner particles constituting the developer are relatively conductive, it is relatively difficult to successfully transfer a toner image to a transfer member in, for example, a toner image transfer type electrostatic copying machine. There's a problem.

On the other hand, apparatuses and methods using the above developer (b) are disclosed, for example, in JP-A-53-3233 and JP-A-53-3233.
It is disclosed in known documents such as JP-A No. 110843, JP-A-53-111737, and JP-A-53-135335. As is clear from such publicly known documents, the above
The apparatus for using the developer of (b) comprises a developer retaining member having a surface which is moved through an endless path of travel, in the form of a roll or an endless belt, and a surface of the developer holding member which faces a part of said path of travel. It includes a developer container having an opening formed therein, and means for charging the developer by an appropriate method such as triboelectric charging. In such a device, the developer contained in the developer container is held on the surface of the developer holding member by an appropriate method, and the developer is made to have a specific polarity before, at the same time, or after that. The developer is charged and then carried to the development area by the movement of the surface of the developer holding member and applied to the electrostatic latent image, thus causing the developer to adhere to the electrostatic latent image in the desired manner and accomplishing development. be done.

When using the developer described in (b) above, the toner particles constituting the developer are relatively insulating, so the above-mentioned problem occurs when using the developer described in (a) above. There are no shortcomings. However, (b) above
The conventional electrostatic latent image developing device using the developer has the following drawbacks or problems to be solved.

That is, when the developer held on the surface of the developer holding member is transported to the developing area to perform development, only a portion of the developer held on the surface of the developer holding member is attached to the electrostatic latent image. Even after the development is completed, the developer remains unevenly on the surface of the developer holding member. Therefore, in the conventional electrostatic latent image developing device using the above developer (b) as disclosed in the above-mentioned known documents, the residual developer is particularly removed from the surface of the developer holding member. In addition to the residual developer, new developer is held on the surface of the developer holding member when the next development is performed. However, in conventional electrostatic latent image developing devices in which residual developer is not specifically removed from the surface of the developer holding member,
It has been found that as development is repeatedly carried out, a problem arises in that the development becomes non-uniform and development spots occur in the developed image (toner image). The causes of such problems are thought to be as follows. The developer remaining on the surface of the developer holding member has been charged prior to the development that has already been carried out, and therefore already holds an electric charge. Therefore, before performing the next development, a charging process is performed on the residual developer that is newly held on the surface of the developer holding member or that already holds an electric charge together with the held developer. . In such a case, due to the presence of residual developer that already holds an electric charge, the charged state of the developer conveyed to the development zone through the charging process tends to be non-uniform. In addition, when new developer is held on the surface of the developer holding member in addition to the residual developer remaining unevenly on the surface of the developer holding member, the remaining developer and the newly held developer The thickness of the developer layer consisting of the developer tends to be non-uniform. The present inventors have discovered that the above-mentioned non-uniformity in the charging state of the developer and non-uniformity in the layer thickness accumulate and increase as development is repeatedly carried out, thus resulting in non-uniform development and It is assumed that development spots occur on the image (toner image).

Furthermore, in the conventional electrostatic latent image developing apparatus using the above developer (b), charge transfer from the surface of the electrostatic latent image forming member on which the electrostatic latent image to be developed is formed, or electrostatic There is a risk that the developer remaining on the surface of the developer holding member after development in the development area or the surface of the developer holding member itself may be abnormally charged due to frictional charging with the surface of the electrolatent image forming member. There were quite a few.

<Object of the Invention> The present invention has been made in view of the above facts, and its main purpose is to provide an electrostatic latent image developing device using the developer described in (b) above, which repeatedly performs development. Also, undesirable development such as uneven development and development spots on the developed image does not occur, and there is no developer remaining on the surface of the developer holding member or the developer holding member after development. It is an object of the present invention to provide a new and excellent electrostatic latent image developing device in which the surface of the electrostatic latent image is reliably prevented from being abnormally charged.

<Solution Means of the Invention> The solution means of the present invention to achieve the above object is to rub the surface of the developer holding member, and the surface of the developer holding member is A peeling member that peels off the developer from the surface of the developer holding member by rubbing is made of a material having a resistivity smaller than that of the developer and is grounded.

That is, the present invention includes a developer holding member having a surface that can be moved through an endless moving path, and a developer container having an opening formed in a portion facing a part of the moving path. A one-component developer containing only toner particles capable of retaining an electric charge, which is contained in the developer container, is held on the surface of the developer holding member and charged, and the developer holding member is charged with an electric charge. The developer is transported to the developing area by the movement of the surface and applied to the electrostatic latent image to be developed, and is contained in the developer container by rubbing the surface of the developer retaining member in the area within the opening. In an electrostatic latent image developing device of the type that is provided with a peeling member that peels off the developer from the surface of the developer holding member; the peeling member is made of a material having a resistivity smaller than the resistivity of the developer. An electrostatic latent image developing device is provided, characterized in that the electrostatic latent image developing device is grounded and grounded.

<Preferred Embodiments of the Invention> Hereinafter, preferred embodiments of an electrostatic latent image developing device constructed in accordance with the present invention will be described in more detail with reference to the accompanying drawings.

Outline of the overall structure Referring to FIGS. 1 and 2, the overall structure of the electrostatic latent image developing device, which is indicated by the number 2, is outlined. The electrostatic latent image developing device 2 includes a developer holding member. 4 and a developer container 6. Developer holding member 4
may be of any form, such as an endless belt, as is well known to those skilled in the art, as long as the surface capable of retaining the developer is of such form that it is moved through an endless path of travel; In the specific example, it is composed of a roller 10 that is rotationally driven in the direction shown by arrow 8 (therefore, the surface of the roller 10 is (transferred through a circular path of travel defined by the surface).
The developer container 6 has an opening formed in a portion of the surface of the developer holding member 4 facing a part of the moving path, that is, in the specific example shown, in a part facing a part of the circumferential surface of the roller 10. It has 12.

In such an electrostatic latent image developing device 2, the developer 14 contained in the developer container 6 comes into contact with the surface of the developer holding member 4 through the opening 12 and is held there, and is also later Charged as detailed. The developer 14 held on the surface of the developer holding member 4 is moved by the movement of the surface of the developer holding member 4, and thus the roller 10 in the illustrated example.
The developing area 16 is rotated in the direction shown by the arrow 8.
carried to. On the other hand, in the development area 16, a suitable electrostatic latent image forming member 18, on the surface of which is formed an electrostatic latent image to be developed, is continuously moved, for example, in the direction indicated by an arrow 20. Thus,
In the development area 16, the charged developer (toner particles) held on the surface of the developer holding member 4 is attached to the surface of the electrostatic latent image forming member according to the potential or charge of the electrostatic latent image. , the electrostatic latent image is developed into a visible image (toner image).

Each component of the electrostatic latent image developing device 2 will be described in more detail below.

Developer In the electrostatic latent image developing device 2 according to the present invention,
It is important to use, as the developer 14, a one-component developer consisting only of toner particles that can be charged by the method mentioned later, in other words, that can retain an electric charge. The toner particles themselves capable of retaining an electric charge are known as relatively insulating toner particles, but in the electrostatic latent image developing device 2 according to the present invention, the toner particles have a resistance of 10 ¹² Ω-
A one-component developer consisting only of toner particles having a resistivity of at least 10 ¹⁴ Ω-cm, particularly at least 10 14 Ω-cm, is preferably used. In addition, toner particles constituting a one-component developer preferably have a small particle size and a large specific surface area so that they can be easily and quickly charged to a saturation charge amount. is 5μ to 30μ, especially 20μ or less, especially 15μ or less,
Preferably.

Developer Holding Member In the electrostatic latent image developing device 2 according to the present invention,
A one-component developer 14 consisting only of relatively insulating toner particles as described above is used, and before such developer 14 retained on the surface of the developer retaining member 4 is conveyed to the development zone 16. As mentioned later, the developer 1 is
4 is charged. Therefore, in order to charge the developer 14 sufficiently and easily, and also to reliably prevent overcharging of the developer 14,
As is well known to those skilled in the art, it is desirable that the resistivity of at least the surface of the developer holding member 4 be smaller than the resistivity of the developer 14. On the other hand, according to the fact confirmed by the inventors through experiments, the specific resistance of the surface of the developer holding member 4 is excessively reduced to 10 ³ Ω-
It has been found that if it is made smaller than cm, the sharpness of the developed image (toner image) decreases and so-called fog tends to occur. Therefore, at least the surface of the developer holding member 4 preferably has a resistivity of 10 ³ Ω-cm or more, which is smaller than the resistivity of the developer 14 described above.

On the other hand, as is well known to those skilled in the art, the relatively insulating developer 14 composed only of toner particles as described above is generally non-magnetic and is not magnetically attracted. When the developer 14 is magnetic, a magnet is disposed within the developer holding member 4, and the development is carried out on the surface of the developer holding member 4 by the action of the magnetic field generated by the magnet. The agent 14 can be conveniently attracted and held magnetically. However, when the developer 14 is non-magnetic, it is necessary to mechanically or electrically hold it on the surface of the developer holding member 4 instead of magnetically attracting and holding it. Therefore, developer 1
4 on the surface of the developer holding member 4 mechanically and electrically, the surface layer of the developer holding member 4 with a thickness of at least 100 μm is made of a material that is flexible and has excellent restorability. Preferably, it is formed from. When the hardness of the surface layer of the developer holding member 4 is excessively high, the amount of the developer 14 held on the surface of the developer holding member 4 tends to decrease excessively, and the holding power of the developer 14 tends to become excessively weak. There is. On the other hand, when the hardness of the surface layer of the developer holding member 4 is excessively small and the restorability is poor, when the free end of the charging member for charging the developer 14 is pressed against the developer holding member 4, as will be mentioned later. In,
The surface of the developer holding member 4 may be easily damaged by the pressure contact, or it may be considerably difficult to control the thickness of the layer of the developer 14 held on the surface of the developer holding member 4. A failure occurs.

By satisfying the above-mentioned requirements on the surface of the developer holding member 4, the developer can be easily and precisely formed into a desired form (for example, a roll form as shown in FIGS. 1 and 2, or an endless belt form). To manufacture the holding member 4, first, a metal support base of a desired form is formed from a suitable metal material such as aluminum, and then a material satisfying the above-mentioned requirements is coated on the surface of the metal support base. It is preferable to bond the surface layers formed by, for example, an adhesive. As the surface layer, the weight percentage is
A material containing 10% or more of silicone rubber is preferably used as a material that is flexible and has excellent restorability. Since silicone rubber is a material with a fairly large specific resistance value, in order to make the specific resistance of the surface layer reach the desired value as mentioned above, a required amount of a resistance control agent such as carbon powder or aluminum powder can be mixed in. .

Furthermore, according to the inventors' experimental results, a high-resistance portion having a specific resistance larger than that of the surface layer is formed on the surface of the above-mentioned surface layer in the form of 50 to 80 meshes. It has been found that the sharpness of the developed image (toner image) can be improved by scattering the toner particles in a distributed manner. Such a high resistance part can be formed by applying silicone rubber or a mixture thereof mixed with an appropriate resistance control agent on the surface of the above-mentioned surface layer by a screen method known per se. I can do it. In this case, it is desirable that the thickness of the high resistance parts scattered on the surface of the above-mentioned surface layer be 500 μm or less. When the thickness of the high resistance portion is greater than 500 μm, the thickness of the layer of developer 14 held on the surface of the developer holding member 4 may be made uniform due to the scattered high resistance portions. becomes difficult.

The form of the developer holding member 4 itself may be any form as long as the surface capable of holding the developer 14 can be moved through an endless movement path, as described above.
From the viewpoint of miniaturization of the device and ease of manufacturing, it is preferable to use a roller-shaped device, especially a hollow roller 10 as shown in FIGS. 1 and 2, which is made hollow to reduce the weight. It is preferable that the When the developer holding member 4 is constituted by a roller 10, an electrostatic latent image forming member 18 is moved in the direction of an arrow 20 in the developing area 16, as shown in FIGS. It is preferable to rotate the roller 10 in the direction shown by the arrow 8 so that the surface of the developer holding member 4 is moved in the same direction as the direction in which the surface of the developer holding member 4 moves. When the roller 10 is rotated in the opposite direction to the direction shown by the arrow 8, the development area 1 is
A so-called reservoir of the developer 14 is generated downstream of the developer 14, and after passing through the development zone 16, the surface of the electrostatic latent image forming member 18 tends to come into contact with the reservoir of the developer 14. After that, the developer 14 falls onto the surface of the electrostatic latent image forming member 18, and the developed image (toner image) tends to have a so-called background stain. Further, it is preferable to rotate the roller 10 at a rotational speed such that the surface of the roller 10 moves at a speed 1.5 to 5 times the speed of movement of the surface of the electrostatic latent image forming member 18. If the moving speed of the surface of the roller 10 is made smaller than 1.5 times the moving speed of the surface of the electrostatic latent image forming member 18, the sharpness of the developed image (toner image) will decrease and an insufficient development phenomenon will occur.
Conversely, if the speed of movement of the surface of the roller 10 is greater than five times the speed of movement of the surface of the electrostatic latent image forming member 18, the sharpness of the developed image (toner image) will decrease and background smear will occur. It has also been experimentally confirmed that scattering of the developer 14 occurs near the developing area 16.

Developer Container In the developer container 6 used in the electrostatic latent image developing device 2 according to the present invention, the developer holding member 4
Near the upstream edge of the opening 12 formed in a portion facing a part of the movement path on the surface of the developer holding member 4, located on the upstream side in the direction of movement of the surface of the developer holding member 4 (i.e., the direction indicated by the arrow 8). In order to prevent the developer 14 from scattering near the downstream edge located on the downstream side, it is desirable that the upstream edge and downstream edge of the opening 12 be configured as follows.

First, to explain the structure of the downstream edge of the opening 12, in the developer container 6 shown in FIGS. The charging member 22 is made of an elastic material, and its free end is defined by a charging member 22 that is brought into pressure contact with the surface of the developer holding member 4. This charging member 22 may be formed integrally with the main body 24 of the developer container 6;
It is convenient to form it separately from the main body 24, which can be formed from a suitable synthetic resin plate or metal plate, and to have one end (the right end in FIG. 1) fixed to the main body 24. The charging member 22 can be made of any elastic material, but as will be explained next, it has an important function of acting on the developer 14 held on the surface of the developer holding member 4 to charge it. From this point of view, the developer holding member 4 described above
It is desirable to form the capacitor from a material having a resistivity smaller than that of the surface of the capacitor. A particularly suitable material for forming charging member 22 may include spring steel. Further, instead of spring steel, metal materials such as molybdenum, tungsten, or aluminum can also be suitably used. When the charging member 22 is formed from spring steel or a metal material such as molybdenum, tungsten, or aluminum, heat treatment or anodic oxidation treatment is performed to form an oxide film on the surface to increase corrosion resistance, wear resistance, etc. It is preferable. The charging member 22 can be formed from a synthetic resin material with relatively low resistance instead of the metal material described above, but in this case, a synthetic resin material with sufficient elasticity and sufficient mechanical strength should be selected. is important.

The above-described charging member 22 shown in FIGS. 1 and 2 has a surface of the developer holding member 4 indicated by the arrow
When moving in the direction indicated by , it contacts the surface of the developer holding member 4 at the opening 12 of the developer container 6 and acts on the developer 14 held therein, causing the developer 14 to be triboelectrically charged. . The charging polarity of the developer 14 due to the triboelectric charging action of the charging member 22 is determined by the interrelationship in the triboelectric series of the material of the developer 14 and the material of the charging member 22, as is well known to those skilled in the art. In addition to triboelectrically charging the developer 14, the charging member 22 charges the developer 14 held on the surface of the developer holding member 4 and transported to the development area 16.
It also performs a so-called panicle length setting function to adjust the thickness of the layer to a desired value. The thickness of the layer of the developer 14 held on the surface of the developer holding member 4 and conveyed to the developing area 16, that is, the length of the ears, is determined to appropriately control the pressing force of the free end of the charging member 22 against the surface of the developer holding member 4. It is adjusted to the required value by adjusting.

In a conventional electrostatic latent image developing device of the type that holds the developer on the surface of the developer holding member 4 and triboelectrically charges the developer before conveying it to the development area, generally, as shown in FIG. As illustrated by the two-dot chain line,
The opening 12 of the developer container 6 is located upstream of the developing area 16 when viewed in the moving direction of the surface of the developer holding member 4.
A charging member 22' whose free end is brought into pressure contact with the surface of the developer holding member 4 at an appropriate position downstream of the downstream edge of the developer holding member 4 is often disposed separately from the developer container 6. Such a conventional electrostatic latent image developing device includes a developer 14 held on the surface of the developer holding member 4 at a location separate from the developer container 6, that is, at a location outside the developer container 6. Since the free end of the charging member 22' acts on the charging member 22', the developer 14 may be separated from the surface of the developer holding member 4 and floated on the upstream side of the free end of the charging member 22', and may be scattered around. . In addition, when the developer 14 is non-magnetic and therefore is held on the surface of the developer holding member 4 not magnetically but mechanically or electrically, the development on the surface of the developer holding member 4 is not possible. Agent 1
Since the adhesion force of the developer 4 is relatively weak and the developer 14 is relatively easily peeled off and floated from the surface of the developer holding member 4, the above-mentioned scattering of the developer becomes a serious problem.

On the other hand, in the illustrated electrostatic latent image developing device 2, the charging member 22 is connected to the opening 1 of the developer container 6.
2 and is configured to perform both charging and frictional functions. In such a case, as can be easily understood from FIG.
The upstream side of the free end of the charging member 22 is located within the developer container 6, and therefore, the peeling of the developer 14 from the surface of the developer holding member 4 that occurs upstream of the free end of the charging member 22 occurs in the developer container 6. Therefore, the developer 14 that is peeled off from the surface of the developer holding member 4 by the action of the free end of the charging member 22 is reliably contained within the developer container 6 and is not released outside the developer container 6. It will not float and scatter.

Next, the structure of the upstream edge of the opening 12 will be explained. In the conventional electrostatic latent image developing device, as is clear from the above-mentioned known literature, the developer container 6
As illustrated by the two-dot chain line in FIG. It is located upstream of the uppermost part of the movement path of the surface of the developer holding member 4, which is the part indicated by number 28 in the illustrated example, when viewed in the movement direction of the surface of the developer holding member 4. Therefore, in the conventional electrostatic latent image developing device, the developer 1 is placed near the upstream edge of the opening 12 of the developer container 6.
There is a problem that 4 is scattered. To explain this point in more detail, it is necessary that the upstream edge 26' located at the position shown by the two-dot chain line in FIG. . Otherwise, as will be readily understood, the developer 14 in the developer container 6 would fall downwardly through the gap between the upstream edge 26' and the surface of the developer retaining member 4 due to its own weight. and scatters to the surrounding area. On the other hand, if the upstream edge 26' is brought into close proximity to or in contact with the surface of the developer holding member 4, the upstream edge 26' will not be attached to the surface of the electrostatic latent image forming member 18 during development in the development area 16. Developer 14 remaining on the surface of developer holding member 4 and moving together with the surface of developer holding member 4
On the other hand, the upstream side of the upstream edge 26' interferes, and as a result, the developer 14 tends to be peeled off from the surface of the developer holding member 4. The developer 14 peeled off from the surface of the developer holding member 4 on the upstream side of the upstream edge 26' falls downward and floats and scatters. Such an undesirable phenomenon is caused especially when the developer 14 is non-magnetic, and therefore the developer 14 cannot be magnetically held firmly enough on the surface of the developer holding member 4, causing mechanical damage. This occurs significantly when a target or electrical need to be maintained is required.

In the illustrated electrostatic latent image developing device 2, in order to reliably prevent the developer 14 from scattering near the upstream edge of the opening 12 of the developer container 6, as clearly illustrated in FIG. The upstream edge 26 of the opening 12 of the container 6 located on the upstream side in the moving direction of the surface of the developer holding member 4 (that is, the direction shown by the arrow 8) is located at the uppermost edge of the movement path of the surface of the developer holding member 4. Upper part, in the illustrated example, than the part indicated by number 28,
It is positioned so as to be close to or in contact with the surface of the developer holding member 4 on the downstream side when viewed in the moving direction of the surface of the developer holding member 4 . In satisfying such requirements, the upstream edge 26 is
However, as clearly shown in FIG. 1, 0 degrees < α <
By means of the free end of the piece 30 extending inclined downwardly and downstream viewed in the direction of movement of the surface of the developer holding member 4 at an angle α of 90 degrees, in particular 10 degrees≦α≦50 degrees. Preferably, an upstream edge 26 is defined.

When the upstream edge 26 of the opening 12 of the developer container 6 is configured as described above, the developer 1 is removed from the surface of the developer holding member 4 on the upstream side of the upstream edge 26.
Even if the developer holding member 4 is peeled off, the peeled developer 14 is pushed downward due to its weight, and therefore the developer retaining member 4
It moves toward the developer container 6 downstream along the surface of the developer container 6 in the direction of movement indicated by the arrow 8, and is collected into the developer container 6. Therefore, the developer 14 peeled off from the surface of the developer holding member 4 on the upstream side of the upstream edge 26 does not float around and scatter.
A piece 3 whose upstream edge 26 extends obliquely as described above.
0, the developer 14 peeled off from the surface of the developer holding member 4 on the upstream side of the upstream edge 26 is guided by the lower surface of the piece 30. The developer holding member 4 moves along with the surface of the developer holding member 4 moving in the direction shown by the arrow 8, and is more reliably collected into the developer container 6. Furthermore, upstream edge 2
6 is extremely close to or in contact with the surface of the developer holding member 4, the developer holding member 4
Due to the presence of the developer 14 moving with the surface of the developer retaining member 4, the surface of the developer retaining member 4 becomes elastically somewhat concave or the piece 30 is elastically deflected, thereby causing the developer 14 to develop. It enters into the agent container 6.

a piece 30 whose free end defines the upstream edge 26;
can be formed integrally with the main body 24 of the developer container 6, or can be formed integrally with the main body 24 as in the illustrated example.
4 and one end (i.e., the upper end) of the body 24 is connected to the main body 24; however, it can be formed from a relatively conductive material having a resistivity lower than that of the developer material 14 and directly connected to the main body 24. Preferably, it is grounded either directly or via a suitable bias voltage source (not shown). In this way, due to charge transfer from the surface of the electrostatic latent image forming member 18 or frictional charging due to friction with the surface of the electrostatic latent image forming member 18, the developer holding member 4 is removed after development in the developing area 16. Even if an undesirable phenomenon occurs in which the developer 14 remaining on the surface of the developer holding member 4 or the surface of the developer holding member 4 itself becomes abnormally charged, the abnormally charged charge can be leaked to the ground through the piece 30.

Peeling Member In the illustrated electrostatic latent image developing device 2 constructed according to the present invention, in addition to the above-mentioned components,
Furthermore, the surface of the developer holding member 4 is rubbed in the area inside the opening 12 of the developer container 6, and the developer 1 attached or held there from the surface of the developer holding member 4 is rubbed.
A peeling member 32 for peeling off 4 is provided.

The stripping member 32 is disposed within the developer container 6, as clearly shown in FIGS. It is preferable that the brush is composed of a so-called brush having a large number of thin wires that are brought into contact with the surface of the developer holding member 4 at the middle part of the opening 12 in the direction. Alternatively, the peeling member 32 may be suitably constructed from a blade piece whose free end is brought into contact with the surface of the developer holding member 4 at a desired position within the opening 12.

When the peeling member 32 as described above is provided, the developer retaining member 4 is not attached to the surface of the electrostatic latent image forming member 18 during development in the development area 16 and is removed from the developer holding member 4 after development. Developer 14 remaining on the surface
is reliably peeled off from the surface of the developer holding member 4 in the developer container 6 by the peeling action of the peeling member 32, and is mixed with other developer 14 in the developer container 6. Therefore, during the next development, the developer 14 in the developer container 6 is completely newly transferred to the downstream side of the peeling member 32 when viewed in the moving direction of the surface of the developer holding member 4 shown by the arrow 8. Agent holding member 4
The newly retained developer 14 is frictionally charged by the action of the charging member 22 and transported to the developing area 16. In this way, each time the development is performed, the developer 14 is completely newly held on the surface of the developer holding member 4, charged, and transported to the development area 16. After the development in the area 16, the developer 14 remaining on the surface of the developer holding member 4 continues to remain without being peeled off, and as the development is repeated, the development becomes uneven.
It is possible to prevent undesirable development in which development spots are formed on a developed image (toner image).

Note that the area is not inside the developer container 6, but is located downstream of the development area 16 and upstream of the upstream edge 26 of the opening 12 of the developer container 6 when viewed in the moving direction of the surface of the developer holding member 4 shown by the arrow 8. It is also possible to arrange the peeling member 32 at the position, but in this case, the peeling member 32
This causes a problem in that the developer 14 peeled off from the surface of the developer holding member 4 is scattered around. Therefore, the stripping member 32 is disposed in the developer container 6 and is configured to act on the surface of the developer holding member 4 in the area within the opening 12, thereby making it possible for the stripping member 32 to It is important to ensure that the developer 14 peeled off from the surface of the developer holding member 4 by the action is held within the developer container 6 without scattering to the surroundings.

The brush or blade piece conveniently used as the stripping member 32, in addition to having suitable elasticity, is formed from a relatively electrically conductive material having a resistivity less than that of the developer material 14, and is It is important that the voltage be connected to ground or via a suitable bias voltage source (not shown). Thus,
Due to the causes already mentioned in connection with the above-mentioned piece 30 defining the upstream edge 26 of the opening 12 of the developer container 6, residual material remains on the surface of the developer retaining member 4 after development in the development zone 16. Even if abnormal charging occurs on the surface of the developer 14 or the developer holding member 4 itself, the abnormally charged charge can be leaked to the ground through the peeling member 32. In order to easily and sufficiently leak abnormally charged charges to the ground, it is desirable that not only the peeling portion 32 but also the piece 30 be formed of a relatively conductive material and grounded.

Thus, the free end of the stripping member 32, which may consist of a brush or a blade piece, extends across its entire width in the axial direction (i.e., in the direction perpendicular to the plane of the paper in FIG. 1) relative to the surface of the developer holding member 4. In order to achieve uniform contact and uniform action, it is necessary to manufacture and position the stripping member 32 with great precision with the surface of the developer holding member 4, but in practice it is difficult to do so. Although it is not impossible, it is extremely difficult, and even if it were possible to do so, as development is repeated, the peeling member 3 may be attached to the surface of the developer holding member 4.
2 will become uneven. In view of this, for example, the developer holding member 4 as shown in the specific example shown in FIG.
When the roller 10 is composed of a roller 10, it is preferable that the roller 10 is rotated in the direction of the arrow 8 and reciprocated over a predetermined range in the direction of its central axis of rotation. In this way, the action of the peeling member 32 on the surface of the developer holding member 4 can be averaged and made sufficiently uniform. Instead of reciprocating the developer holding member 4 in the axial direction, the peeling member 32 can also be reciprocated in the axial direction, but if the developer holding member 4 is reciprocated in the axial direction, the developing area Since the developing action at 16 can be averaged in the axial direction and extremely uniform development can be achieved, the developer holding member 4 can be moved along the axis by an appropriate driving means (not shown) without causing any particular problems. As long as the developer holding member 4 can be reciprocated in the direction
It is preferable to reciprocate in the axial direction.
Of course, if desired, both the developer retaining member 4 and the stripping member 32 can be reciprocated in the axial direction separately so as not to be synchronized with each other.

[Brief explanation of drawings]

FIG. 1 is a simplified sectional view showing a preferred embodiment of an electrostatic latent image developing device constructed according to the present invention. FIG. 2 is a simplified partially cutaway perspective view of the electrostatic latent image developing device shown in FIG. 1. 2... Electrostatic latent image developing device, 4... Developer holding member, 6... Developer container, 12... Opening of developer container, 14... Developer, 16... Development area, 18...
Electrostatic latent image forming member, 22... Charging member, 32...
Peeling member.

Claims (1)

[Scope of Claims] 1. A developer holding member having a surface that can be moved through an endless movement path, and a developer container having an opening formed in a portion facing a part of the movement path, A one-component developer made of only toner particles capable of retaining an electric charge, which is housed in the developer container, is held on the surface of the developer holding member and charged, and the surface of the developer holding member is charged. The developer is transported to the developing area by the movement of the developer and applied to the electrostatic latent image to be developed, and the developer is contained in the developer container by rubbing the surface of the developer holding member in the area within the opening. In an electrostatic latent image developing device of the type that is provided with a peeling member that peels off the developer from the surface of the holding member; the peeling member is made of a material having a resistivity smaller than the resistivity of the developer. An electrostatic latent image developing device characterized by being grounded. 2. The electrostatic latent image developing device according to claim 1, wherein the developer has a specific resistance of 10 ¹² Ω-cm or more. 3. The electrostatic latent image developing device according to claim 1 or 2, wherein the peeling member is constituted by a brush having a large number of thin lines whose free end comes into contact with the surface of the developer holding member. 4. The electrostatic latent image according to claim 1 or 2, wherein the peeling member is made of a flexible material and is composed of a blade piece whose free end abuts the surface of the developer holding member. Developing device. 5. Claims 1 to 4, wherein the developer holding member is constituted by a roller that is rotationally driven and continuously reciprocated in the direction of the rotation axis.
3. The electrostatic latent image developing device according to any one of the preceding paragraphs.