JPH10228174A - One-component developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain toner from being stuck to a toner regulating member and to form a stable good-quality image by making a developer carrier area adjacent to the downstream side of a discharging member in the surface moving direction of the developer carrier communicate with a toner housing part. SOLUTION: Excess toner on a developing sleeve 2 is discharged by the discharging member 19a on which discharge voltage VD is impressed. Since the electrified amount of low electrified toner is made smaller than qth (the lowest electrified amount of toner necessary to hold the toner by the sleeve 2), the low electrified toner is separated from the sleeve 2 when it comes to a position facing to a path 5a, and is recovered to a buffer chamber 5 through the path 5a. Even when high electrified toner comes to the position facing to the path 5a, it is continuously held by the sleeve 2 because the electrified amount of the high electrified toner does not get smaller than qth . Then, it is discharged by the discharging member 19b on which the discharge voltage VD is impressed so as to make the electrified amount smaller than qth , whereby it is recovered to the buffer chamber 5 through the path 5b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for developing and visualizing an electrostatic latent image formed on an electrostatic latent image carrier in an image forming apparatus such as a copying machine and a printer.

[0002]

2. Description of the Related Art Developing devices used in electrophotographic image forming apparatuses such as copiers and printers are roughly classified into one-component developing devices and two-component developing devices. The former is a one-component developing device. A developer (toner) is used, and the latter uses a two-component developer (toner and carrier) as the developer.

[0003] In general, a one-component developing device is configured such that toner supplied to a developer carrier whose surface moves is passed between a toner regulating member in contact with the surface and the surface so that the charged toner thin film is applied to the surface. Transported as a layer to the development area,
The toner is supplied to the developer supply side while being held by the developer carrying member, and the excess toner remaining without being consumed after the development is developed.

However, in such a one-component developing device, for example, when the fluidity of the toner is improved more than usual in a low humidity environment, the chargeability of the toner is also improved. Highly charged toner accumulated on the carrier tends to increase. As a result, the amount of toner attracted to the developer carrier increases, and the amount of toner adhered to the developer carrier cannot be regulated by the toner regulating member, and an abnormal amount of toner is conveyed to the electrostatic latent image carrier side. As a result, the non-image portion is developed with toner (so-called abnormal toner adhesion).

Further, the toner accumulated on the developer carrier is subjected to stress by the toner regulating member many times, so that the toner is rubbed and fixed on the developer carrier, so-called toner filming occurs. Eventually, the image quality deteriorates. Further, the toner is liable to be deteriorated due to the stress (reduction of the particle diameter of the toner, falling off of the fluidizing agent silica, etc.), and the followability of solid black is deteriorated.

Further, when the amount of toner accumulated on the developer carrier increases, the toner newly supplied to the carrier becomes
Since the toner is charged not only by the original toner regulating member but also by friction between the toners, the amount of the charged toner having the opposite polarity to the normal charging polarity increases, which eventually leads to deterioration of the image quality. In order to solve such a problem in the one-component developing device, a developing device shown in FIG. 4 has been proposed. The illustrated developing device includes a driving roller 1 that is driven to rotate counterclockwise in the drawing by driving means (not shown). The driving roller 1 is inserted into a developing sleeve 2 having an inner diameter slightly larger than the outer diameter of the roller. The both ends of the sleeve 2 are pressed against the drive roller 1 by the pressing guide 3 from behind. The slack portion 20 formed on the opposite side by this pressure contact is the electrostatic latent image carrier (photosensitive drum in this example) PC
Is in flexible contact with Further, a toner regulating blade 4 (toner regulating member) is in contact with the developing sleeve 2 from the same side as the pressing guide 3.

The driving roller 1, the pressing guide 3, the toner regulating blade 4 and the like are provided in the developing device case C. A developing bias voltage V _B from the power source 21 to the developing sleeve 2, the voltage from the power source 41 to the toner regulating blade 4 V
_BLD can be applied. A buffer chamber 5 is provided behind the developing sleeve 2, and a toner supply chamber 6 is further provided behind the buffer chamber 5. A toner supply rotating member 7 (rotated counterclockwise in the drawing) is provided in the buffer chamber 5, and a toner supply chamber 6 is provided in the toner supply chamber 6. A toner stirring / supply rotating member 8 (rotated clockwise in the figure) is disposed. Further, a lower seal member 9 for preventing toner from leaking from the buffer chamber 5 to the outside contacts the lower surface of the developing sleeve 2.

The developing sleeve 2 is a photosensitive drum PC
A toner discharging member 19 ′ is in contact with the sleeve 2 on the downstream side of the developing area facing the developing device.
0 are also available apply a discharging bias voltage V _D from. A material having good conductivity is dispersed in the toner neutralizing member 19 ′, and the surface is formed of a material whose surface is biased toward the same polarity as the normal charging polarity of the toner on the charging series with respect to the developing sleeve 2. is there.

According to this developing device, the toner T sent from the toner supply chamber 6 to the buffer chamber 5 by the rotation of the rotary member 8 is sequentially developed in the developer supply area by the rotation of the toner supply rotary member 7. It is supplied to the surface of the sleeve 2. On the other hand, the sleeve 2 is driven to rotate by the frictional force with the drive rotation of the drive roller 1, and the toner T
Is charged by frictional charging under the pressure of the toner regulating blade 4 by passing between the toner regulating blade 4 and the developing sleeve 2, and the developing bias voltage V _B
The charge is injected from the regulating blade 4 into the toner according to the potential difference between the voltage V _BLD applied to the toner regulating blade 4 and the toner, and the charge amount of the toner is adjusted by these. Then, a thin layer of a predetermined thickness is held on the sleeve surface,
It is conveyed to the developing area facing the photosensitive drum PC, where it is used for developing the electrostatic latent image under the developing bias V _B by the power source 21.

With the rotation of the sleeve 2, the excess toner T after development passes between the charge removing member 19 'in contact with the sleeve 2 on the downstream side of the developing area and the sleeve 2, and contacts the member. While returning to the toner supply side. Then, when the toner T passes through the member, the charge is removed by friction with the member, and the electric force required to hold the toner T on the developing sleeve 2 is weakened, and the toner T moves away from the surface of the sleeve 2 to the toner supply side. It is in an easy state.

Since a material having good conductivity is dispersed in the charge removing member 19 ', electric charges generated in the member due to friction between the member and toner passing through the member are released through the material. The accumulation of electric charges in the member is prevented. Further, the toner T which contacts pass the toner discharging member 19 ', a developing bias voltage V _B and the toner discharging member 1
9 'to the neutralization bias voltage V _D applied from the power supply 190
The amount of charge removal is adjusted according to the potential difference of the toner. Therefore, by setting the appropriate voltage V _D , that is, the appropriate potential difference, when the surplus toner comes again to the toner regulating blade 4, the toner is removed from the surface of the sleeve 2. It is possible to create a state where it is easy to move away from the supply side.

Here, the surface of the toner neutralizing member 19 'is formed of a material that is biased toward the same polarity as the normal charging polarity of the toner in the charging series as compared with the sleeve 2, as described above.
In addition, when a material having good conductivity is dispersed and the toner is negatively charged, the relationship between the voltage V _BLD applied to the toner regulating blade 4 and the voltage V _D applied to the member 19 ′ is expressed as V _D > In order to satisfy the condition of V _BLD , and when the toner T is positively charged, the relationship between the voltage V _BLD applied to the toner regulating blade 4 and the voltage V _D applied to the member 19 ′ is V _D < The voltage is applied so as to satisfy the condition of V _BLD .

[0013]

However, in such a conventional one-component developing apparatus, even if the charge amount of the toner is reduced after printing, for example, the charge amount of the toner removed by the charge removing member is substantially reduced. since constant is, imbalance of the charge removing the toner charging, the reverse polarity toner is generated by the charge removing bookmarks too, which may become the cause of fog on the image, also, the developing bias potential V _B to the toner regulating blade 4 When a bias potential V _BLD having the same polarity as the charged polarity of the toner is applied to the toner, the opposite polarity toner is attracted to the toner regulating blade 4 and stays at that position to prevent the toner from rubbing. This causes the toner to be fused to the toner regulating blade 4 to cause so-called toner sticking. There is a problem that leads to the deterioration.

For example, if the balance between the charge and the charge elimination of the toner is lost due to the temperature and humidity environment and the charge exceeds the charge elimination performance, the amount of the highly charged toner accumulated on the developing sleeve 2 without separating from the developing sleeve 2 increases. Tend. Therefore, the toner attracted to the developing sleeve 2 is subjected to stress by the toner regulating blade 4 many times, so that the toner is rubbed on the developing sleeve 2, so that there is a problem that the so-called toner filming occurs and the image quality is deteriorated.

Accordingly, the present invention provides a method for supplying a toner from a toner container to a surface of a developer carrier whose surface moves, charging the toner, and holding the charged toner on the surface of the developer carrier. Then, the developer is conveyed to a developing area facing the electrostatic latent image carrier, subjected to development, and returned to the toner supply side while remaining on the developer carrier surface without being consumed after development. A component developing device, wherein even if the charged state of the toner fluctuates due to the surrounding environment, printing durability, etc., it is possible to appropriately remove static electricity from the toner returned to the toner supply side, thereby causing image fog and toner on the developer carrying member. To provide a one-component developing apparatus capable of forming a stable high-quality image by suppressing the occurrence of filming, toner sticking to a toner regulating member having a predetermined thickness of toner on the surface of a developer carrying member, and the like. The challenge That.

[0016]

In order to solve the above-mentioned problems, the present invention provides the following two types of one-component developing devices. The first type of developing device supplies a toner from a toner container to the surface of the developer carrier whose surface moves,
The toner is charged, and the charged toner is held on the surface of the developer carrier, transported to a development area facing the electrostatic latent image carrier, subjected to development, and left unconsumed after development. A one-component developing device for returning excess toner to a toner supply side while holding the toner on the surface of the developer carrier. The one-component developing device extends in a direction crossing the direction of movement of the surface of the developer carrier, and has It has two or more static elimination members that abut on the developer carrier surface at a downstream position in the carrier surface movement direction, and each static elimination member is spaced apart from an adjacent static elimination member in the developer carrier surface movement direction. The one-component developing device according to claim 1, wherein the developer carrier body surface areas arranged adjacent to each other on the downstream side in the developer carrier body movement direction of each of the charge removing members communicate with the toner accommodating portion. Developing device).

The second type of developing device supplies toner from a toner container to the surface of the developer carrier whose surface moves, charges the toner, and transfers the charged toner to the developer. The toner is conveyed to the developing area facing the electrostatic latent image carrier while being held on the surface of the carrier, subjected to development, and surplus toner remaining without being consumed after the development is held on the surface of the developer carrier. A one-component developing device that returns to the toner supply side, extends in a direction transverse to the direction of movement of the surface of the developer carrier, and is located downstream of the developing region in the direction of surface movement of the developer carrier. A charge removing member that is in contact with the surface; the charge removing member is provided with a plurality of holes that are spaced apart in the direction of movement of the developer carrier surface, and one opening of each of the holes is the developer carrier; The other opening faces the toner collection It is a one-component developing device and wherein the (second developing device) that communicates with section.

In the first developing device, the surface area of the developer carrier adjacent to each of the charge removing members on the downstream side in the direction of movement of the developer carrier surface (hereinafter, simply referred to as “downstream side”) is the toner container. Leads to. Such a developer carrier surface area may directly face the toner storage unit or may communicate with the toner storage unit via a passage following the toner storage unit. In the latter case, such a developer carrier surface area faces the passage. In any case, a collection path leading to the toner storage section is provided on the downstream side adjacent to each of the charge removal members, and one set of the charge removal member and the collection path adjacent to the downstream side of the charge removal member are provided. In view of this, the first developing device includes two or more sets of the charge removing unit.
These are, for example, a first set of neutralizing members on the downstream side of the developing area,
The first set of collection paths, the second set of charge eliminating members, the second set of collection paths, the third set of charge eliminating members, the third set of collection paths,... The collection path of the final set may be disposed upstream (hereinafter simply referred to as “upstream”) in the direction of movement of the surface of the developer carrier from the region where the toner supplied to the surface of the developer carrier is charged.

The charge eliminating member of the second developing device has a plurality of holes, one opening of each hole faces the developer carrier, and the other opening communicates with the toner accommodating portion. However, it is conceivable that the other opening directly faces the toner storage unit or that the other opening communicates with the toner storage unit via a passage following the toner storage unit. In the latter case, the other opening faces the passage. Such a passage may be common to each hole. The size of each hole may be sufficiently large with respect to the particle size of the toner so as not to hinder the passage of the toner. In any case, these holes are provided at intervals in the direction of movement of the surface of the developer carrier. The hole arrangement in the direction transverse to the direction of movement of the developer carrier may be continuous or may be provided at intervals.
In addition, when viewed as the entire static elimination member, typically, there can be mentioned a plurality of holes which are dispersed and formed almost uniformly as a whole. In such a case, the total opening area of these holes is not limited thereto, but may be about 20 to 30% of the area of the surface of the static elimination member that contacts the developer carrier.

Each static elimination member of the first developing device and the static elimination member of the second developing device are higher in charging series than the developer carrier.
The toner may be formed of a material offset toward the same polarity as the normal charging polarity of the toner. In addition, a static elimination bias voltage may be applied to these static elimination members by a static elimination bias power supply. Further, a conductive material may be dispersed in the charge eliminating member in order to suppress unnecessary accumulation of charges.

In any of the above-mentioned developing devices, the toner supplied to the surface of the developer carrier can be charged by a toner regulating member which is in contact with the surface of the developer carrier on the upstream side of the developing area, for example. In this case, the supplied toner can be charged by passing the toner between the developer carrying member and the toner regulating member, and can be held as a charged toner thin layer having a uniform thickness on the surface of the developer carrying member. be able to.

In any of the above-described developing devices, the toner contained in the toner containing portion is supplied to the surface of the developer carrier whose surface moves in the developer supply area, and is charged by, for example, a toner regulating member, and the developer is charged. It is held on the surface of the carrier and transported to the developing area, where it is used for developing the electrostatic latent image on the electrostatic latent image carrier. In this development, a developing bias voltage can be applied to the developer carrier.

The surplus toner after development is conveyed to the downstream side of the developing area while being held by the developer carrier as the surface of the developer carrier moves. Then, in the first developing device, the excess toner comes into contact with each of the static elimination members arranged downstream of the developing area, and in the second developing device, the excess toner contacts the static elimination member provided with the holes. You. Note that both the first and second developing devices are configured based on the idea that the charge removal amount of the toner is substantially proportional to the contact distance with the charge removal member.

Then, in the first developing device, the surplus toner having a different charge amount is discharged as follows and separates from the surface of the developer carrier. That is, at the stage where the toner has passed between the first set of the neutralizing member and the developer carrying member, the toner that has been neutralized until the charge amount becomes smaller than the minimum charge amount required to be held by the developer carrying member, When it comes to the position facing the first set of recovery paths adjacent to the downstream side of the developer carrier, it separates from the surface of the developer carrier and is returned to the toner container through the recovery path. At this stage, the toner having the charge amount equal to or more than the minimum charge amount is further discharged by the second set of charge removing members. From the toner storage unit. Thereafter, similarly, the toner having the charge amount equal to or more than the minimum charge amount is further neutralized by the next set of neutralization members,
When the charge amount becomes smaller than the minimum charge amount, the set is returned to the toner storage unit from the collection path. As described above, according to the first developing device, the charge can be removed according to the charge amount of the surplus toner.

The sum of the contact distances between the charge removing members and the developer carrier may be determined based on the assumed charge amount of the highly charged toner among the surplus toner. In addition, regarding the number of sets of the static elimination unit including the static elimination member and the collection path, if the amount of static elimination by one static elimination member is too large, the conventional developing device (the conventional developing device includes one set of the static elimination unit) It can be considered that the toner is charged to the opposite polarity due to excessive charge removal as in the case of (1). The distance may be shortened.

Further, in the second developing device, the surplus toner having a different charge amount is discharged as follows, and separates from the surface of the developer carrier. That is, for a relatively low charged toner, at a relatively early stage when the toner is passed between the charge removing member and the developer carrier, the toner is smaller than the minimum charge amount necessary to be held by the developer carrier. When the charge is removed up to the charge amount, and when it comes to a position facing a hole provided in the charge removing member, it is separated from the surface of the developer carrying member and returned to the toner container through the hole. Also, for relatively highly charged toner,
After being sufficiently rubbed by the charge removing member to have a charge amount smaller than the minimum charge amount, when the charge removing member comes to a position facing a hole, the charge is returned to the toner storage unit through the hole. As described above, also in the second developing device, it is possible to perform the charge elimination according to the charge amount of the surplus toner.

In the second developing device, the contact distance between the charge removing member and the developer carrier may be determined based on the charge amount of the highly charged toner among the surplus toner. As described above, in the developing device of the present invention, when the surplus toner is discharged on the downstream side of the developing area, the charge is removed in a state where the toner charge removing section and the charge removed toner collection section alternately appear. Even if the charge amounts of the individual surplus toners on the developer carrier are different, the charge amounts of these toners can all be reduced to almost constant values and collected at the developer supply side, and image fog and toner It is possible to suppress the adhesion of the toner to the regulating member, the filming of the toner on the developer carrier, and the image memory due to the residual toner.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view of a one-component developing device according to one embodiment of the present invention. This developing device
In this embodiment, reversal development is performed using a negatively chargeable toner. The developing device shown in FIG. 1 employs the charge elimination members 19a and 19b described later in place of the toner charge elimination member 19 'in the conventional development device shown in FIG. Hereinafter, a portion related to static electricity removal of surplus toner in the developing device according to the present invention will be particularly described in detail.

On the downstream side of the developing region where the developing sleeve 2 faces the photosensitive drum PC, static elimination members 19a and 19b extending in the axial direction of the developing sleeve 2 are arranged in contact with the developing sleeve 2 in order. Further downstream of the charge removing member 19b, a seal member 9 for preventing toner from leaking from the buffer chamber 5 to the outside is disposed in contact with the developing sleeve 2. These static elimination members 19a and 19b and seal member 9 are elastic members 191a and 191 respectively.
b, 91 are supported by the developing device case C.
In addition, the elastic member is provided because the member 19 is provided under an appropriate pressure.
a, 19b and 9 are brought into contact with the sleeve 2.

A material having good conductivity is dispersed in each of the charge removing members 19a and 19b, and a material whose surface is biased toward the same polarity as the normal charge polarity of the toner on the charging series with respect to the developing sleeve 2 is used. It is formed with. In addition, these static elimination members 19a and 19b are provided with a static elimination bias power supply 19, respectively.
From 0, a neutralization bias voltage V _D can be applied.

A passage 5a extending in the axial direction of the developing sleeve 2 is provided on the downstream side adjacent to the charge removing member 19a, in other words, between the charge removing members 19a and 19b. One end of the passage 5 a faces the developing sleeve 2, and the other end communicates with the buffer chamber 5. That is, the static elimination member 19a
The surface area of the developing sleeve 2 on the downstream side adjacent to the above communicates with the buffer chamber 5. Similarly, on the downstream side adjacent to the charge removing member 19b, a passage 5b extending in the axial direction of the developing sleeve 2 is provided. One end of the passage 5b faces the developing sleeve 2, and the other end thereof is in the buffer chamber 5b. Leads to.

Except for the above points, the configuration is substantially the same as that of the conventional apparatus shown in FIG. 4, and the same parts are denoted by the same reference numerals as in FIG. That is, in the device of FIG.
1 is a driving roller, 2 is a developing sleeve into which the roller is inserted, 3 is a pressing guide for pressing the sleeve against the driving roller 1, 4 is a toner regulating blade in contact with the developing sleeve 2, 5 is the buffer chamber, 6 Is a toner supply chamber, 7 is a toner supply rotating member of the buffer chamber 5, and 8 is a toner supply chamber 6.
, And T is a used toner. The driving roller 1 and the toner supply rotating member 7 are driven to rotate counterclockwise in the figure, and the toner stirring / supply rotating member 8 is rotated.
Is driven to rotate clockwise in the figure. In the developing sleeve 2, the slack portion 20 formed on the opposite side by the pressing of the pressing guide 3 is in flexible contact with the surface of the photosensitive drum PC in this example.

According to this developing device, similarly to the conventional developing device, the toner T is supplied to the surface of the developing sleeve 2 which is driven to rotate in the developer supply area in the developing device case C, and the toner regulating blade 4 A charge is applied by frictional charging under the pressure of the toner regulating blade 4 by passing between the sleeve 2 and the toner regulating blade 4 to form a thin layer having a predetermined thickness, which is held on the surface of the developing sleeve 2 and faces the photoconductor PC. It is transported to where it is used for developing the electrostatic latent image based on the development bias voltage V _B is applied.

The surplus toner on the developing sleeve 2 after passing through the developing area has a different charge amount as described above, and is held on the developing sleeve 2 by the image force of the charged charges. Here, assuming that the minimum charge amount of the toner required for the developing sleeve 2 to hold the toner is q _th , when the charge is removed and the charge amount of the surplus toner becomes smaller than q _th , the toner separates from the developing sleeve 2. However, if the charge is removed too much and the toner is charged to a polarity opposite to the normal charge polarity (the polarity charged by the toner regulating blade 4), it causes image fog and toner sticking to the blade 4. Since the charge removal amount of the toner is almost proportional to the contact distance with the charge removal member, the contact distance with the charge removal member is increased for the toner with a high charge amount, and the contact distance with the charge removal member is shortened for the toner with a low charge amount. By doing so, the charge removal amount of the toner can be made appropriate. The static elimination in the developing device of the present invention is based on such a concept.

The surplus toner on the developing sleeve 2 is first
Neutralization voltage V _D is discharged by the charge removal needles 19a being applied. As a result, the low-charge toner has a charge amount q
_{th, and} is separated from the developing sleeve 2 when it comes to a position facing the passage 5a.
Will be collected. Further, highly charged toner, the charged amount is not less than q _th even when came to a position facing the passage 5a, but continues to be held on the developing sleeve 2, followed further neutralization voltage V _D and is applied neutralization The charge is removed by the member 19b, the charge amount is made smaller than q _th , and the passage 5b
Through the buffer chamber 5.

As described above, according to the developing device of the present invention, the amount of charge removal can be made appropriate in accordance with the amount of charge of surplus toner, whereby image fog, filming of toner on the developing sleeve 2, toner It is possible to stably form a high-quality image by suppressing the occurrence of toner sticking or the like on the regulating member 4. In this example, the static elimination member and the collection passage are configured in two sets, but a plurality of sets may be further provided. At this time, the contact distance of the plurality of sets of each charge eliminating member with the developing sleeve 2 (in other words, the contact distance between the toner and each charge eliminating member).
Are the same, the number of sets of the static elimination member and the collection passage is increased,
When the contact distance of each static elimination member is shortened, the amount of static elimination by each static elimination member decreases, and excessive static elimination can be prevented. Further, by adjusting the total contact distance, it is possible to prevent a situation in which the highly charged toner does not separate from the developing sleeve 2 due to insufficient static elimination.

Next, using a developing apparatus of the type shown in FIG. 1, a test is conducted to examine the state of fogging of 5000 blank sheets after printing, the adhesion of toner to the toner regulating blade 4, and the occurrence of toner filming on the developing sleeve ( Experimental Example 1) was performed, and the results are shown. As a comparative example, a similar test (Comparative Example 1) was performed using the conventional developing device shown in FIG. 4, and the results are also shown.

Experimental Example 1 and Comparative Example 1 were respectively tested under the following conditions. (Experimental Example 1) Developing device used: developing device of the type shown in FIG. 1 (developing device of the present invention) Static eliminating bias voltage: V _D = −200 [V] Developing bias voltage: V _B = −300 [V] Toner regulation Blade applied voltage: V _BLD = -100 [V] Toner T: Next negatively chargeable toner (average particle size: 10 [μ]
m]) Thermoplastic polyester resin: 100 parts by weight Carbon black MA # 100 (manufactured by Mitsubishi Chemical Industry Co., Ltd.): 4 parts by weight Negative charge control agent: 3 parts by weight Hydrophobic silica: 0.8 parts by weight ( (As a post-treatment agent) Static elimination members 19a and 19b: tapes in which carbon powder is dispersed in tetrafluoroethylene resin.

The lower seal member was also used. Contact distance (nip width) of the discharging member 19a with the developing sleeve 2: 2 mm Contact distance (nip width) of the discharging member 19b with the developing sleeve 2: 2 mm Width of the collecting passage 15a: 2 mm Width of the collecting passage 15b: 2 mm 2: Toner regulating blade made of polyamide 4: Toner supply rotating member made of stainless steel 7: Aluminum photosensitive drum PC: negatively charged photosensitive drum (Comparative Example 1) Developing device used: developing device shown in FIG. 4 (conventional developing device) Apparatus) Contact distance (nip width) of the charge removing member 19 ′ with the developing sleeve 2: 4 mm Other conditions are the same as those of the experimental example 1.

Next, the evaluation results of the images obtained in each of the above experimental examples are shown. Fogging of blank paper Toner sticking on the developing sleeve of the toner regulating blade Filming Experimental Example 1 ○ ○ ○ Comparative Example 1 × × ○ In the above image evaluation, “○” indicates that there is no toner development in the non-image area, toner regulation. A good state in which toner does not adhere to the blade 4 and a good state in which toner filming does not occur on the developing sleeve 2 are shown, respectively.
“X” indicates a defective state.

From this experiment, according to the developing device of the present invention,
Fog of blank paper, toner sticking to toner regulating blade,
It can be seen that a good image can be obtained without toner filming on the developing sleeve. Another embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a schematic sectional view showing another example of the developing device according to the present invention, and FIG. 3 is a schematic exploded perspective view of the device.

The developing device shown in FIGS. 2 and 3 employs a static elimination member 192 which also serves as a seal member in place of the seal member 9 and the toner static elimination member 19 'in the conventional development device shown in FIG. The other parts are the same as the conventional ones, and the description is omitted. The parts having the same operation are denoted by the same reference numerals. In FIG. 3, reference numeral 200 denotes a bearing member that rotatably positions the developing sleeve 2 with respect to the case C.

The charge removing member 192 extends in the axial direction of the developing sleeve 2, and is in contact with the developing sleeve 2 on the downstream side of the developing area where the developing sleeve 2 faces the photosensitive drum PC. The charge removing member 192 receives a charge removing voltage V from the power supply 190.
_D can be applied. The charge removing member 192 is made of a material in which a material having good conductivity is dispersed and whose surface is biased toward the same polarity as the normal charging polarity of the toner on the charging series with respect to the developing sleeve 2. It is formed in.

Further, the charge removing member 19 formed in a sheet shape is used.
2, a large number of holes 192h are provided uniformly dispersed throughout. One opening of each of the holes 192h faces the surface of the developing sleeve 2, and the other opening faces a common collection passage 5c for each of the holes leading to the buffer chamber 5. The holes 192 h are uniformly dispersed over substantially the entirety of the charge removing member 192, and the total area of the holes 192 h with respect to the area of the charge removing member 192 is about 20 to 30%. Each of the holes 192h has a diameter of about 200 μm, and the developing device of this embodiment uses a toner having an average particle diameter of 10 μm.

According to this developing device, the surplus toner having a different charge amount on the developing sleeve 2 after passing through the developing area comes into contact with the charge removing member 192 and is discharged. The charge removal amount of the toner by the charge removal member 192 is also substantially proportional to the contact distance between the toner and the charge removal member 192. Therefore, when the contact distance between the low charge toner and the charge removal member 192 is relatively short, the charge amount of the toner is reduced. 2 is smaller than the minimum charge amount q _th required to be held in the hole 192.
h is returned to the buffer chamber 5 through the recovery passage 5c.
Also, after the charged amount of the highly charged toner becomes smaller than q _{th, the} toner is returned from the hole 192h to the buffer chamber 5 through the collection passage 5c. As described above, also in the developing device of the present embodiment, it is possible to appropriately remove the charge according to the amount of charge of the surplus toner.
It is possible to suppress the occurrence of the filming of the toner on the upper side and the adhesion of the toner on the toner regulating member 4 and to stably form a high-quality image.

[0046]

According to the present invention, toner is supplied from the toner storage section to the surface of the developer carrier whose surface moves, the toner is charged, and the charged toner is placed on the surface of the developer carrier. And transported to a developing area facing the electrostatic latent image carrier, subjected to development, and moved to the toner supply side while remaining excess toner not consumed after development on the surface of the developer carrier. This is a one-component developing device for returning, even if the charged state of the toner fluctuates due to the surrounding environment, printing durability, etc., it is possible to appropriately remove the charge from the toner returned to the toner supply side, thereby causing image fog, Toner filming,
It is possible to provide a one-component developing apparatus capable of suppressing the occurrence of toner sticking to the toner regulating member having a predetermined thickness of the toner on the surface of the developer carrier, thereby forming a stable high-quality image.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a one-component developing device according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a one-component developing apparatus according to another embodiment of the present invention.

FIG. 3 is a schematic exploded perspective view of the developing device shown in FIG. 2;

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drive roller 2 Developing sleeve 21 Developing bias power supply 3 Pressing guide 4 Toner regulating blade 5 Buffer chamber 6 Toner supply chamber 7 Toner supply rotating member 8 Toner stirring / supply rotating member 9 Lower seal member T Toner PC Photoconductor drum C Developing device case 19a, 19b, 192, 19 'Static elimination member 192h Hole of static elimination member 192 190 Static elimination bias power supply 5a, 5b, 5c Collection passage

Claims (4)

[Claims] 1. A method according to claim 1, wherein a toner is supplied from a toner accommodating portion to the surface of the developer carrier whose surface moves, and the toner is charged.
The charged toner is held on the surface of the developer carrier, conveyed to a development area facing the electrostatic latent image carrier, subjected to development, and the excess toner remaining without being consumed after development is removed from the developer. A one-component developing device that returns to the toner supply side while being held on the surface of the carrier, extends in a direction crossing the direction of movement of the surface of the developer carrier, and extends from the development area in the direction of surface movement of the developer carrier. At least two static eliminators abut on the surface of the developer carrier at a downstream position, and each static eliminator is arranged at a distance from an adjacent neutral eliminator in the direction of movement of the developer carrier surface. The one-component developing device according to claim 1, wherein a surface area of the developer carrier adjacent to the downstream side of the member in the direction of movement of the surface of the developer carrier communicates with the toner accommodating portion. 2. The charge removing member according to claim 1, wherein the surface of the charge removing member is made of a material whose surface in contact with the developer carrying member is biased toward the same polarity as the normal charging polarity of the toner in the charging series with respect to the developer carrying member. The one-component developing device according to claim 1, wherein 3. A toner supply unit supplies toner to the surface of the developer carrier whose surface moves, and charges the toner.
The charged toner is held on the surface of the developer carrier, conveyed to a development area facing the electrostatic latent image carrier, subjected to development, and the excess toner remaining without being consumed after development is removed from the developer. A one-component developing device that returns to the toner supply side while being held on the surface of the carrier, extends in a direction crossing the direction of movement of the surface of the developer carrier, and extends from the development area in the direction of surface movement of the developer carrier. A static elimination member that contacts the surface of the developer carrier at a downstream position, and the static elimination member is provided with a plurality of holes spaced in a direction in which the surface of the developer carrier moves, and one of the holes is The opening of (1) faces the surface of the developer carrying member, and the other opening communicates with the toner container. 4. The static elimination member is formed of a material whose surface in contact with the developer carrying member is biased toward the same polarity as the normal charging polarity of the toner on the charging series with respect to the developer carrying member. The one-component developing apparatus according to claim 3, wherein