JPH1039622A - Developing method and device for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain fog and cloud generated by causing of low charged toner and the toner different from desired charge polarity by charging the toner in stable. SOLUTION: A developing agent separating means 4 for forming a layer of designated thickness while frictional charging developing agent G on as developing agent carrier 2 or for separating the developing agent G from the developing agent carrier 2 at an intermediate step for forming a plurality of formed layer thickness restraining member 3 and layer forming of the developing agent layer thickness restraining member 3 is mounted in a device. For example, a small space 6 is formed in a part of a pressure welded area with the developing agent layer thickness restraining member 3 and the developing agent carrier 2 as the developing agent separating means 4. An alternating field generating means 5 that the alternating field acts is mounted to this small space 6. And if necessary, an offset voltage applying means 7 for generating direct field for moving the developing agent G to the developing agent carrier 2 side is added.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an image forming apparatus such as an electrophotographic copying machine or a printer, and more particularly to a developing device for removing an electrostatic latent image formed on a latent image carrier. The present invention relates to an improvement in a developing device that visualizes using a component developer.

[0002]

2. Description of the Related Art In recent years, as electrophotographic copying machines, laser beam printers, and the like have become smaller and simpler, a one-component developing system has attracted attention as a developing system for visualizing an electrostatic latent image. Conventionally, as a developing device for visualizing an electrostatic latent image using a one-component developer, those disclosed in JP-A-47-13088 and JP-A-53-167341 are known. This is to form a thin layer of non-magnetic one-component developer toner on the surface of the developer carrier, and to visualize the electrostatic latent image formed on the surface of the latent image carrier by the developer carrier. It is. In such an apparatus, it is necessary to regulate the thin layer of the toner carried on the developer carrying member to a predetermined thickness in order to prevent the occurrence of uneven development density and toner spillage.

As means for forming a thin layer, in a conventional developing device, a toner adhered to the surface of the developer carrier by a layer thickness regulating member which is pressed against the surface of the developer carrier at a rotation direction outlet portion of the apparatus main body. The method of keeping the layer thickness constant is widely used. However, in this method, it is difficult to uniformly feed the toner into a narrow wedge-shaped space formed by the layer thickness regulating member and the developer carrying member, and further, the toner is made to bite into the narrow wedge-shaped space. However, there is a problem that stripes and unevenness are generated in a thin layer on the developer carrying member, and that density unevenness and stripes are generated in a developed image.

In order to solve the above problem, a developing device disclosed in Japanese Patent Application Laid-Open No. 60-103371, for example, generates an alternating voltage between a developer carrying member and a layer thickness regulating member. This alternating electric field causes the toner to reciprocate, so that the toner can bite into the wedge-shaped space between the layer thickness regulating member and the developer carrier, and a uniform toner layer can be formed on the surface. What has been proposed has already been proposed.

[0005]

In the conventional developing device using the above-described one-component developing method, the penetration of the toner into the wedge-shaped space between the layer thickness regulating member and the developer carrying member is good. Although an apparently uniform toner layer is formed, when the toner on the developer carrying member passes between the layer thickness regulating member and the developer carrying member, a gap between the layer thickness regulating member and the developer carrying member occurs. Since the configuration is such that the developer is charged by frictional charging caused by the above, there is a technical problem that the charge amount becomes insufficient and it is difficult to form a uniformly charged developer layer. That is, when a multi-layered developer passes between the layer thickness regulating member and the developer carrying member, the charge amount of the developer becomes non-uniform between the upper layer, the intermediate layer, and the lower layer. There is a technical problem that it is difficult to form a uniformly charged developer layer, for example, a low-charged toner or a toner having a charge polarity different from a desired charge is generated without replacing the developer. As a result, fogging of the ground may occur on the print, and the print may be scattered in a cloud shape to contaminate the inside of the machine.

Therefore, the present invention stably charges the toner and suppresses fogging and clouding caused by the generation of a low-charged toner or a toner having a different charging polarity from a desired one.
An object of the present invention is to provide a developing method and a developing device capable of obtaining a good image by developing.

[0007]

That is, the developing method according to the present invention employs, as shown in FIG.
In the developing method for developing the electrostatic latent image formed on the surface of the latent image carrier 1 by forming a thin layer of the one-component developer G on the surface of the developer G, the developer G is formed on the developer carrier 2. Developing layer thickness regulating step 100 for forming a layer to a predetermined layer thickness while frictionally charging the developer G. The developing step is provided in the middle of the developing layer thickness regulating step 100 and temporarily removes the developer G from the developer carrier 2. And an agent stripping step 200.

In such technical means, the one-component developer G, which is the subject of the present application, may be non-magnetic or magnetic. Further, the developer layer thickness regulation step 100 is not limited as long as it regulates the layer thickness of the developer G while being frictionally charged, regardless of whether it is in contact with the developer carrier 2 or not. It does not matter. Further, in the developer peeling step 200, any method of electrical, mechanical, or magnetic may be used as long as the developer G is once released, but in the normal developing step, an alternating electric field is used as a developing bias. In many cases, it is preferable to use this alternating electric field.

As shown in FIG. 1 (b), an apparatus invention embodying the above-described method invention is to form a thin layer of a one-component developer G on the surface of a developer carrier 2, In a developing device for developing an electrostatic latent image formed on the surface of the latent image carrier 1, one or a plurality of developing processes for forming a layer to a predetermined thickness while frictionally charging the developer G on the developer carrier 2 Developer layer thickness regulating member 3 and developer layer thickness regulating member 3
And a developer stripping means 4 for temporarily releasing the developer G from the developer carrier 2 in the middle of the layer formation.

Here, the developer layer thickness regulating member 3 includes
One or a plurality may be provided. In the case of one, it is necessary to provide the developer peeling means 4 on the developer layer thickness regulating member 3 itself. When a plurality of thickness regulating members 3 are provided, the developer layer thickness regulating member 3 itself may be provided with a developer peeling means 4, or the developer may be peeled independently of the developer layer thickness regulating member 3. Means 4 may be provided.

In such a device invention, as the developer removing means 4, there are electrical, mechanical and magnetic means. Examples of the mechanical means include functional means (brush, blade, etc.) for mechanically scraping the developer G, and examples of the magnetic means include peeling the developer G with an electromagnet, Means to return to The electric means includes an alternating electric field generating means 5 for applying an alternating electric field to the developer G on the developer carrier 2.
The one provided with. Here, it is generally preferable to use a developing bias power supply as the alternating electric field generating means 5, but an independent electric field generating means may be used independently of the developing bias power supply.

As an embodiment in which the developer peeling means 4 is provided on the developer layer thickness regulating member 3 itself, for example, a minute space is formed in a part of the developer layer thickness regulating member 3 in a pressure contact area with the developer carrier 2. 6, an alternating electric field generating means 5 for applying an alternating electric field to the minute space 6 is provided. In this embodiment, the minute space 6 may be one or more concave portions extending along the longitudinal direction of the developer layer thickness regulating member 3 (the axial direction of the developer carrier 2). It may be a set of many independent concave portions, or a combination of both. Here, for example, as an example, in which the minute space 6 is one concave portion (concave stripe) extending in the longitudinal direction of the developer layer thickness regulating member 3, there is a pressure contact region on the upstream side, and A mode is obtained in which the non-contact region is located downstream of the body 2 rotation direction and the pressure contact region is located further downstream. Further, when the minute space 6 is formed, better results can be obtained by configuring the developer layer thickness regulating member 3 so that the minute space 6 (non-contact region) gradually decreases in the vicinity of the downstream pressure contact region. Can be On the other hand, as the alternating electric field generating means 5, a minute space 6 (non-contact area)
A good result can be obtained by generating an AC electric field of 1.5 × 10 ⁶ V / m or more.

Further, from the viewpoint of effectively avoiding the situation where the developer G remains in the minute space 6 or the like, the developer peeling means 4 is provided with a direct current (DC) for moving the developer G to the developer carrier 2 side. It is preferable to add an offset voltage applying means 7 for generating a field. At this time, the minute space 6
Good results can be obtained by generating an effective DC electric field of 2.0 × 10 ⁵ V / m or more in the (non-contact region).

Further, from the viewpoint of ensuring that a DC electric field is generated by the offset voltage in the minute space 6, the offset voltage applying means 7 is provided on the surface of the minute space 6 facing the developer carrier 2. It is preferable that the offset voltage for generating the DC electric field is applied to the electrode.

Next, the operation of the above technical means will be described. The operation of the developing device will be described with reference to FIG. However, the developer peeling means 4 is used as the developer layer thickness regulating member 3.
A small space 6 is formed in a part of the pressure contact area with the developer carrier 2 and an alternating electric field generating means 5 for applying an alternating electric field to the minute space 6 is provided as an example. . First, charging is performed by friction in the pressure contact area on the upstream side of the minute space 6 (non-contact area) of the developer layer thickness regulating member 3, and then, when the minute space 6 is reached, an alternating electric field formed in the minute space 6 Of the developer (toner) from the developer carrier 2 and reciprocating motion of the developer,
The lower layer is replaced, and charging by friction is performed again in the downstream pressure contact area of the minute space 6. As a result, the developer having uneven charging is uniformly charged. Further, since the offset voltage applying means 7 moves the developer G toward the developer carrier 2 by the action of the generated DC electric field, the offset voltage applying means 7 moves to the developer carrier 2 without leaving the developer in the minute space 6. Make sure to put it back.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings. First Embodiment FIG. 2 shows a first embodiment of a laser printer incorporating a developing device to which the present invention is applied. In FIG. 1, a charging device 2 is provided around a photosensitive drum 11 as a latent image carrier.
0, developing device 30, transfer device 40, cleaning device 5
0 is arranged. The photosensitive drum 11 is a charging device 20
The electrostatic latent image is uniformly written on the photosensitive drum 11 by a laser beam 84 generated by a laser beam scanning device 80 having a semiconductor laser and a polygon rotating mirror 81 built therein. The written electrostatic latent image is developed by the developing device 30. At this time, the laser light 84 writes the image area, and the toner having the same polarity as the surface potential of the photosensitive drum 11 charged by the charging device 20 is used as the laser light 84 on the photosensitive drum 11. It is developed in the irradiation part.

Next, the toner image developed on the photoreceptor drum 11 is transferred by the transfer device 40 onto the transfer paper conveyed from the paper feed tray 71 via the paper feed roll 72 by the registration roll 73. After the completion of the transfer, the transfer paper is conveyed to the fixing device 60 by the conveyance belt 74, and subjected to a fixing process. The fixing device 60 includes a heating roll 61 and a pressure roll 62, and the transfer paper is inserted between these rolls and is fixed by heat and pressure. After the transfer process,
The residual toner on the photoreceptor drum 11 is cleaned by the cleaning blade 51 of the cleaning device 50, and subsequently enters the charging process, and repeats all the above processes to output a plurality of continuous prints.

Next, the developing device of the present embodiment will be described in detail with reference to FIG. The developing device includes a developing roller 31 as a developer carrying member composed of a metal roller rotatably supported opposite to the photosensitive drum 11 (see FIG. 2) on which the electrostatic latent image is formed. The toner supply roll 32 as a roller-shaped porous conductive member rotatably supported while the parts are in contact with each other, regulates the layer thickness of a non-magnetic one-component developer composed of only toner, and forms a toner on a developer carrier. 331 of elastic rubber material forming a thin layer of
The main part thereof is composed of a layer thickness regulating member 33 composed of a blade supporting member 332 made of an elastic metal spring material.

A developing bias power supply 35 is connected to the developing roll 31, and a predetermined developing bias is applied to the developing roll 31 by the developing bias power supply 35. The developing bias power supply 35 is set so as to apply an AC voltage having a voltage Vp-p = 2 kV and a frequency f = 3 kHz superimposed on a DC voltage of -400 V, for example. The blade 331 is bonded to a metallic blade support member 332 such as SUS using, for example, urethane rubber, and the blade support member 332 is grounded. The blade thickness when pressed against the developing roll 31 is 1.0 m
m, between the blade supporting member 332 and the developing roll 31 by the AC voltage of the developing bias power supply 35, 2.0 ×
10 ⁵ V / m is generated.

An example of the blade 331 used in FIG. 3 will be described in more detail with reference to FIG. When the blade 331 is pressed against the developing roll 31, the blade 331 forms a non-contact area A having a concave portion having a rectangular cross section along the axial direction in the pressing area with the developing roll 31, and a contact area on the upstream and downstream sides thereof. It is shaped to form a and b.

According to such a blade 331, the toner 36 adhering to the developing roll 31 from the upstream side of the blade 331 in the area a of the pressure contact area between the blade 331 and the developing roll 31, and the friction between the blade 331 and the developing roll 31 It is charged by the friction with 31. At this time, the toner is charged by friction of the upper part of the toner layer with the blade 331,
The intermediate layer is the friction caused by the toner, and the lower layer is the developing roll 31.
As a result, the charge distribution is not uniform but wide.

Next, the toner 36 is transported to the non-contact area A by the rotation of the developing roller 31, and the toner 36 is separated from the developing roller 31 in an AC electric field formed between the developing roller 31 and the blade supporting member 332. And reciprocate. Thereby, on the toner layer formed in the area a,
The middle and lower layers are replaced, and transported to the next area b.

The toner layer conveyed to the area b is more uniform because the upper layer is charged by friction with the blade 331, the intermediate layer is charged by friction between the toners, and the lower layer is charged by friction with the surface of the developing roll 31. Problems such as generation of ground fog on prints and scattering in the form of a cloud and contaminating the inside of the machine are solved.

FIG. 5 shows the electric field intensity E1p-p (V / V) of the AC electric field between the blade supporting member 332 and the developing roll 31.
m) shows the relationship between the chargeability of the toner on the developing roll. The horizontal axis indicates the electric field intensity E1p-p (V / m) of the AC electric field between the developing roll 31 and the blade supporting member 332, and the vertical axis indicates the distribution width measured by CSG (charge spectrograph method).

As shown in FIG. 5, the electric field intensity E of the AC electric field
When 1p-p is 1.5 × 10 ⁶ V / m or less, the charge distribution becomes broad, exceeding the fog tolerance on actual prints. This is the developing roll 31
It is considered that when the electric field strength E1p-p of the AC electric field formed between the blade and the blade supporting member 332 is small, the toner does not reciprocate sufficiently. Accordingly, the electric field intensity E1p-p (V / m) of the AC electric field between the developing roll 31 and the blade supporting member 332 is E1p-p (V / m) ≧ 1.5 × 10 ⁶ V / m. Is desirable.

The shape of the concave portion 333 (non-contact area A) of the blade 331 is not limited to a rectangular cross section, but may be, for example, as shown in FIGS. May be a concave portion 333 having a semicircular cross section, or as shown in FIG. 7, a concave portion 333 having a triangular cross section may be appropriately selected.

Second Embodiment FIG. 8 shows a developing device according to a second embodiment of the present invention. In the figure, the configuration of the main part of the developing device is the same as that used in the first embodiment. A developing bias power supply 35 is connected to the developing roll 31, and a predetermined developing bias is applied to the developing roll by the developing bias power supply 35. The developing bias power supply 35 supplies, for example, a DC voltage −400 V and a voltage Vp−p =
It is set so that an AC voltage of 2 kV and a frequency f = 3 kHz is superimposed and applied. The blade 331 is bonded to a metallic blade supporting member 332 such as SUS using, for example, urethane rubber. The blade supporting member 332 has an offset voltage applying power source for generating an electric field for moving the toner to the developing roll 31 side. 37 are provided.

Here, when the accuracy of the portion where the blade 331 is pressed against the developing roll 31 is deteriorated in the first embodiment, when the toner passes through the non-contact area and reenters the pressed portion, the blade 331 is pressed. It is difficult for the toner to enter between the developing roller 31 and the non-contact region A, and the toner is clogged in the non-contact area A, and the toner layer unevenness on the developing roller 31 is slightly confirmed. The cause is
Due to the pressed state of the blade 331 and the shape of the pressed area,
This is because when the toner reciprocates in the non-contact area A and is transported to the area b again, a stable state cannot be ensured.

FIG. 9 shows the relationship between the effective DC electric field between the developing roll 31 and the blade supporting member 332 and the unevenness of the toner layer on the developing roll 31. The horizontal axis represents the effective DC electric field intensity E2p-p (V / m) between the developing roll 31 and the blade support member 332, and the vertical axis represents the grade of layer unevenness. Thus, the electric field intensity E2p-p is 2.0 × 10 ⁵ V
/ M or more, it can be seen that the layer unevenness falls within the allowable range of ≦ G2. Here, the allowable range of layer unevenness is a range in which unevenness due to layer unevenness cannot be confirmed in a halftone portion on a print. Therefore, the electric field intensity E2p-p (V / m) between the developing roll 31 and the blade supporting member 332 is desirably E2p-p ≧ 2.0 × 10 ⁵ V / m, thereby setting conditions and the like. A stable thin layer can be obtained with respect to disturbance due to

Embodiment 3 FIG. 10 is a sectional view of a main part showing an embodiment of the present invention.
In particular, when a non-magnetic developer is used, not only the developer transport force due to the magnetic force cannot be expected, but also there is no magnetic force to draw the developer toward the developing roll 31. Therefore, when the non-contact area A formed by the layer thickness regulating member 33 and the developing roll 31 is used near the downstream pressure contact area and the layer thickness regulating member 33 is rapidly reduced, the developing roll 31 is moved in the direction indicated by an arrow. Even when the toner is rotated in the direction, the toner merely slides on the developing roll 31, and the toner 36 is hard to enter between the blade 331 and the developing roll 31, and the upper, middle, and lower layers are uniformly replaced in the non-contact area A. Cannot be charged. In contrast, the layer thickness regulating member 33 according to the present embodiment
Has a curved surface portion 334 such that the non-contact area A formed by the layer thickness regulating member 33 and the developing roll 31 gradually decreases in the vicinity of the downstream pressure contact area. In this type, by rotating the developing roll 31 in the direction of the arrow, the toner 36 easily enters between the blade 331 and the developing roll 31, and the upper, middle, and lower layers are replaced in the non-contact area A. Can be uniformly charged.

Fourth Embodiment FIG. 11 is a cross-sectional view showing a main part of a developing device according to a fourth embodiment of the present invention. In the figure, a layer thickness regulating member 33 according to the present embodiment
In order to generate an electric field for moving the toner toward the developing roll 31, an electrode 38 is provided on the bottom of the concave portion 333 of the blade 331.
Is provided. For example, the electrode 38 and the developing roll 3
When a voltage of 200 V is applied to the offset voltage applying power source 37 at a distance of 1 mm to the developing roller 1, an effective DC electric field (electric field strength: 2.0 × 10 ⁵ V) that moves the toner to the developing roll 31 side in the non-contact area A / M). Accordingly, it is possible to suppress the toner from being clogged in the non-contact area A and to cause the toner layer unevenness on the developing roll 31, and to obtain stable charging uniformity.

Fifth Embodiment FIG. 12 is a sectional view of a main part showing a developing device according to a fifth embodiment of the present invention. In the same figure, the layer thickness regulating member 33 according to the embodiment is a developing roll 3 of a blade 331.
Non-contact areas A and B comprising two concave portions 335 and 336 having a rectangular cross section, for example, along the axial direction in the pressure contact region with
And contact areas a, upstream, intermediate, and downstream thereof, respectively.
b and c are formed.

According to the present embodiment, from the upstream of the blade 331, the toner 36 adhering to the developing roll 31 is subjected to the friction between the blade 331 and the developing roll 31 in the area a of the pressure contact area between the blade 331 and the developing roll 31. And it is charged by friction. Next, the toner 36 is conveyed to the non-contact area A by the rotation of the developing roll 31, and in an AC electric field formed between the developing roll 31 and the blade supporting member 332, the toner 36 is separated from the developing roll 31 and reciprocated. exercise. Thereafter, the rotation of the developing roll 31 causes recharging in the contact area b, peeling of the toner in the non-contact area B, and recharging in the contact area c. As described above, in this embodiment, by repeating charging and peeling of the toner, uneven charging between the upper and lower layers of the toner is eliminated, and the toner is uniformly charged.

Sixth Embodiment FIG. 13 is a cross-sectional view of a main part showing a developing device according to a sixth embodiment of the present invention. In the figure, the layer thickness regulating member 33 according to the present embodiment
Non-contact areas A and B formed of two recesses 335 and 336 having a rectangular cross section, for example, are formed along the axial direction within the pressure contact area of the developing roller 31 with the developing roller 31.
b and c are formed.
By providing an electrode 38 at the bottom of 35 and 336, and connecting an offset voltage applying power supply 37 to this electrode 38, in addition to the alternating electric field in the non-contact areas A and B, a DC electric field for moving the toner to the developing roll 31 side Is made to act.
According to this embodiment, the same operation and effect as those of the fifth embodiment are obtained, and clogging of the toner in the non-contact areas A and B is effectively avoided.

Seventh Embodiment FIGS. 14A and 14B show a layer thickness regulating member used in a developing device according to a seventh embodiment of the present invention. In the figure,
The blade 331 of the layer thickness regulating member 33 does not have a concave portion extending in the axial direction as in the first to sixth embodiments, but has a large number (in the circumferential direction of the developing roll 31) in the pressure contact area of the blade 331 with the developing roll 31. Are arranged in the non-contact area A.
Are formed. Even in this type,
Functions and effects similar to those of the first to sixth embodiments are achieved.

Eighth Embodiment FIG. 15 is a cross-sectional view showing a main part of a developing device according to an eighth embodiment of the present invention. In the figure, the developing device is arranged at a predetermined interval with respect to the developing roll 31 and the toner 3
The first layer thickness regulating member 33 (1), which regulates the layer thickness while frictionally charging the developing roller 6 on the developing roller 31, is disposed in non-contact with the developing roller 31 and passes through the first layer thickness regulating member 33 (1). Separation electrode 34 for separating separated toner 36 from developing roll 31
A second layer thickness regulating member 33 (2) which is arranged at a predetermined distance from the developing roll 31 and regulates the layer thickness while frictionally charging the toner 36 passing through the peeling electrode 34 onto the developing roll 31. And In the present embodiment, an alternating electric field of the developing bias power supply 35 acts between the peeling electrode 34 and the developing roll 31, and a DC electric field generated by the offset voltage applying power supply 37. ) Works.

In this embodiment, different from the first to seventh embodiments, the thickness of the toner is regulated by a plurality of members. In this embodiment, the toner is temporarily stopped during the frictional charging of the toner. Since the toner is peeled off, the upper and lower layers of the toner are stirred and mixed, and the toner is uniformly charged.

Embodiment 9 FIGS. 16 (a) and 16 (b) are main part explanatory views showing a developing device according to Embodiment 9 of the present invention. In the figure, a developing device is provided in contact with a developing roll 31 and a first layer thickness regulating member 33 (1) that regulates a layer thickness while frictionally charging a toner 36 (not shown) onto the developing roll 31; The toner 36 that has passed through the first layer thickness regulating member 33 (1) is
A scraping brush 39 (or a scraping blade 39 ′) that mechanically scrapes the toner from 1 and a developing roller 31 are disposed in contact with the developing roller 31 to regulate the layer thickness while frictionally charging toner 36 (not shown) on the developing roller 31. Second layer thickness regulating member 33 (2)
And Preferably, the scraping blade 39 'is provided with a toner passage port 391 as necessary. Also in the present embodiment, similar to the eighth embodiment,
Since the toner is once mechanically peeled off during the frictional charging of the toner, the upper and lower portions of the toner are agitated and mixed,
The toner is charged uniformly. As described above, Embodiments 1 to 9
Is not limited to application alone, and these may be appropriately combined.

[0039]

As described above, according to the present invention,
While a one-component developer (toner) is friction-charged by the developer layer thickness regulating member to form a layer having a predetermined thickness, an alternating electric field is applied to a non-contact area such as a minute space to carry the developer. Since the developer is once separated from the body, the upper, middle and lower layers of the developer are replaced by the separation and reciprocation of the developer from the developer carrier by an alternating electric field and the like, and the pressure contact area is again formed. , Charging is performed by friction. For this reason, the developer having uneven charging is uniformly charged, and fog and cloud generated due to generation of a low-charged developer or a developer different from a desired charging polarity are suppressed, and a good image is obtained by development. Can be.

Furthermore, if a DC electric field is applied by the offset voltage applying means in the process of peeling the developer, the developer in the minute space can be reliably returned to the developer carrier, and Clogging of the developer can be avoided.

[Brief description of the drawings]

FIG. 1A is an explanatory diagram illustrating a developing method according to the present invention, and FIG. 1B is an explanatory diagram illustrating an outline of a developing device according to the present invention.

FIG. 2 is a schematic view showing an embodiment of a laser printer in which a developing device to which the present invention is applied is incorporated.

FIG. 3 is an explanatory sectional view of a developing device used in the first embodiment.

FIG. 4 is an enlarged sectional view of a main part of FIG.

FIG. 5 shows the electric field intensity E1p-p of the alternating electric field between the blade supporting member and the developing roll in the developing device of the first embodiment.
FIG. 4 is a graph showing the relationship between (V / m) and the chargeability of the toner on the developing roll.

6A is an explanatory view showing a modified example of the concave portion of the blade used in the first embodiment, and FIG. 6B is a perspective explanatory view of the blade.

FIG. 7 is an explanatory view showing another modified example of the concave portion of the blade used in the first embodiment.

FIG. 8 is an explanatory sectional view of a developing device used in the second embodiment.

FIG. 9 is a graph showing a relationship between an effective DC electric field between the blade supporting member and the developing roll and unevenness of toner layer on the developing roll in the second embodiment.

FIG. 10 is an explanatory sectional view of a main part of a developing device used in a third embodiment.

FIG. 11 is an explanatory sectional view of a main part of a developing device used in a fourth embodiment.

FIG. 12 is an explanatory sectional view of a main part of a developing device used in a fifth embodiment.

FIG. 13 is an explanatory cross-sectional view of a main part of a developing device used in a sixth embodiment.

14A is an explanatory view showing a concave portion of a blade used in Embodiment 7, and FIG. 14B is a perspective explanatory view of the blade.

FIG. 15 is an explanatory sectional view of a main part of a developing device used in an eighth embodiment.

FIG. 16 is an explanatory sectional view of a main part of a developing device used in a ninth embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Latent image carrier, 2 ... Developer carrier, 3 ... Developer layer thickness regulating member, 4 ... Developer stripping means, 5 ... Alternating electric field generation means,
6 ... minute space, 7 ... offset voltage applying means, 100 ...
Developer layer thickness regulation step, 200: developer removal step, G: one-component developer

Continued on the front page (72) Inventor Yoji Matsui 2274 Hongo, Ebina City, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd.

Claims (7)

[Claims] An electrostatic latent image formed on the surface of a latent image carrier (1) by forming a thin layer of a one-component developer (G) on the surface of a developer carrier (2). A developing layer thickness regulating step of forming a layer to a predetermined layer thickness while frictionally charging the developer (G) on the developer carrier (2) (100).
Provided in the middle of the developer layer thickness regulation step (100);
A developer stripping step (200) for once releasing the developer (G) from the developer carrier (2). 2. The developing method according to claim 1, wherein the developer removing step (200) is performed by an alternating electric field. 3. The development of an electrostatic latent image formed on the surface of the latent image carrier (1) by forming a thin layer of the one-component developer (G) on the surface of the developer carrier (2). A developer layer thickness regulating member (3) for forming a layer having a predetermined thickness while frictionally charging a developer (G) on a developer carrier (2); A developing device comprising: a developer stripping unit (4) for temporarily separating the developer (G) from the developer carrier (2) at a stage during the layer formation of the layer thickness regulating member (3). 4. The developing device according to claim 3, wherein the developer peeling means (4) is provided with an alternating electric field generating means for applying an alternating electric field to the developer (G) on the developer carrier (2). (5) A developing device comprising: 5. The developing device according to claim 3, wherein the developer peeling means (4) has a small size in a part of the developer layer thickness regulating member (3) in a pressure contact area with the developer carrier (2). Space (6)
And an alternating electric field generating means (5) for applying an alternating electric field to the minute space (6). 6. The developing device according to claim 3, wherein the developer peeling means (4) is applied with an offset voltage for generating a DC electric field for moving the developer (G) toward the developer carrier (2). A developing device to which means (7) is added. 7. The developing device according to claim 6, wherein a minute space (6) is formed in a part of a pressure contact area of the developer layer thickness regulating member (3) with the developer carrier (2). Wherein the offset voltage applying means (7) applies the offset voltage for generating the DC electric field to an electrode provided on a surface of the minute space (6) facing the developer carrier (2). A developing device.