JPH0371162A - Developing device - Google Patents

Abstract

PURPOSE:To prevent the splashing of a toner by installing a small electrode for preventing splashing of a developer near the downstream side of a developer flying region between a latent image carrying member and a developer carrying member. CONSTITUTION:The wire electrode 37 is extended near the downstream side of the developer flying region 36 between a photosensitive drum 11 and a developing sleeve 32. The prescribed bias voltage of the same polarity as the charge polarity of the developer 31 is impressed by a power source 38 to this wire electrode 37. The developer 31 which tends to splash from the developer flying region 36 between the photosensitive drum 11 and the developing sleeve 32 is, therefore, repulsed by the electric field generated by the wire electrode 37 and is returned to the developing sleeve 32 side, by which the developer 31 is recovered into a developing device 25 as the developing sleeve 32 rotates.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a developing device used in an image forming apparatus such as an electrophotographic copying machine or a laser beam printer.

[Prior Art] Conventionally, image forming apparatuses such as the above-mentioned electrophotographic copying machines and laser beam printers have functions such as simultaneous two-color copying and color copying in addition to those capable of copying ordinary black monochrome images. There is something. Then, the image forming apparatus has the following features:
Depending on the function, some are equipped with a black developing device or a plurality of developing devices such as a red developing device in addition to a black developing device.

In addition, the developing method adopted in the above developing device is as follows:
Depending on the image forming conditions, a two-component magnetic brush development method uses a two-component developer consisting of toner and carrier, and develops by bringing a magnetic brush of this developer into contact with the latent image carrier; There is a one-component jumping development method in which a one-component developer consisting only of toner is used and the developer is caused to fly between a latent image carrier and the image is developed.

However, in the case of the above-mentioned developing device, especially in the case of a developing device using a -component developer, the developer flies between the developing device and the latent image carrier, and the latent image carrier has a relatively high rotational speed. Since the developing device rotates at a high speed, there is a problem in that the developer leaks from the gap between the developing device and the latent image carrier and splashes around, contaminating the surrounding area. This problem is particularly noticeable in a developing device that uses a -component developer, but it is also a problem in a developing device that uses a two-component magnetic brush developing method.

In addition, in an image forming apparatus equipped with a plurality of developing devices, developer leaking from the upstream side in the rotational direction of the latent image carrier may
There was a problem in that the particles invaded the inside of the developing device located on the downstream side and caused color mixing of the developer.

Therefore, as a solution to the above problems,
A method as shown in Japanese Patent No. 2-223773 has already been proposed. As shown in FIG. 10, a plurality of developing means 101.
In the electrostatic latent image developing device J3 in which the developing means 101 and 102 are arranged side by side, each of the developing means 101 and 102 is installed in an adjacent partition part with the tip facing the surface of the electrostatic latent image carrier 100, and
The toner mixing prevention plate 103 has a conductive surface at least at its tip, and a bias applying means 104 applies a bias voltage to the toner mixing prevention plate 103.

[Problems to be Solved by the Invention] However, in the case of the above-mentioned conventional technology, there is a problem as shown below. Namely, in the case of the above-mentioned developing device, the toner contamination prevention plate 103 Other developing means 10
Even if it is possible to prevent to some extent the mixing of toners 1 to 2 into the developing means 102, it does not fundamentally prevent the scattering of gutter from the developing means 10''l and 102.
The toner particles 1 to 01 that are about to scatter from the developing means 1
There is a problem in that the toner particles accumulate inside the toner and interfere with the normal toner transport characteristics. Further, the downstream developing means 102
If toner scattering becomes a problem, there is a problem in that it cannot be prevented at all.

[Means for Solving the Problems] Therefore, the present invention was made to solve the above-mentioned problems of the prior art. It is an object of the present invention to provide a developing device which can prevent 1-toner from accumulating in a developing means and also prevent 1-toner from scattering in a developing section downstream of a latent image carrier.

That is, the present invention provides a developing device (d3) that converts an electrostatic latent image formed on a latent image carrier into a visible image by flying a developer held around the developer carrier. Near the downstream side of the developer flying area between the image carrier and the developer carrier,
An electrode for the small developer carrier 142 is installed, and a predetermined bias voltage is applied to this electrode for preventing scattering of developer.1:
It is composed of

Further, the present invention provides a developing device that visualizes an electrostatic latent image formed on a latent image carrier by causing developer held around the developer carrier to fly. An airflow generating part 11'4 is installed near the downstream side of the developer flying region between the grooved image carrier and the developer carrier to generate an airflow that guides the flying developer into the apparatus. has been completed.

Furthermore, the present invention provides a developing device that visualizes an electrostatic latent image formed on a latent image carrier by flying a developer held around the developer carrier. Near the downstream side of the developer flying area between the developer carriers, an airflow generating part is installed at least on the surface of which is electrically conductive, and which avoids generating an airflow that guides the flying developer into the container. At the same time, a predetermined bias voltage is applied to the first airflow generating section.

[Function 1] In the present invention, a small developer scattering prevention electrode is installed near the downstream side of the developer flying region between the latent image carrier and the developer carrier, and a predetermined electrode is installed on the developer scattering prevention electrode. Since the structure is configured to apply a bias voltage of Since the developer is removed and returned into the developing device, scattering of the developer is fundamentally prevented.

Further, in the present invention, an airflow generating member for generating an airflow that guides the flying developer into the device is installed near the downstream side of the developer flying region between the latent image carrier and the developer carrier. Therefore, the developer that tries to scatter to the outside from the developer flying area between the latent image carrier and the developer carrier is
The developer is returned to the airflow generating member into the apparatus, and scattering of the developer is fundamentally prevented.

In general, in the present invention, at least the surface of the latent image carrier is electrically conductive in the vicinity of the downstream side of the developer flying region between the developer carriers, and an air current is provided to guide the flying developer into the device. Since the airflow generating member is installed and a predetermined bias voltage is applied to the airflow generating member, the developer is not scattered to the outside from the flying region between the latent image carrier and the developer carrier. The developer to be used is returned to the inside of the developing device by the airflow generating member, and is also repelled by the electric field created by the airflow generating member and returned to the inside of the developing device, so that scattering of the developer is fundamentally prevented.

[Example] The present invention will be explained below based on illustrated embodiments.

FIG. 3 shows an electrophotographic copying machine to which the developing device according to the present invention can be applied. In the figure, 1 is a platen glass on which an original 2 is placed, and the original 2 placed on the Braden glass 1 is illuminated by a light source 3. And the foul light image from the original 2 is a mirror image, 5.6.7
．． 8.9 and the lens 10 onto the photosensitive drum 11. The surface of the photosensitive drum 11 is uniformly charged by a primary charger 12 prior to image exposure.

Then, as described above, the image of the original document 2 is exposed to light on the surface of the photosensitive drum 11, and an electrostatic latent image is formed. This electrostatic latent image is transferred to a selectively activated developing device 13 or 14.
: It is developed and becomes a toner image.

The toner image formed on the surface of the photoreceptor drum 11 is
The image is transferred onto the transfer paper 15, which is conveyed to the surface of the photoreceptor drum 11, by being charged by the transfer charger 16, as will be described later. After the transfer paper 15 is fed from the paper feed cassette 17 by the paper feed roller 8, it is temporarily stopped at the position of the registration roller 9, and is conveyed to the surface of the photoreceptor drum 11 by the registration roller 9 at a predetermined timing. be done.

The transfer paper 15 on which the toner images 1 to 1 above have been transferred is 111 minutes
After being separated from the surface of the photoreceptor drum 11 by the charging of the electrifier 20, it is conveyed to the fixing device 22 via the conveyor belt 21. The 1-toner image is fixed on the transfer paper 15 by the fixing device 22, and the transfer paper 15 is discharged onto the discharge tray 23. In the figure, 24 (leaner).

The developing device 13 uses black toner to perform normal image development, and the developing device 14 uses color toner such as red or blue to perform development during two-color copying or the like.

FIG. 1 shows an embodiment of a developing device according to the present invention, which is used, for example, as one or both of the developing devices 13 and 14 described above.

In the figure, numeral 25 indicates a developing device, and this developing device 25 includes a popper 30 that accommodates a developer 31. Inside the hopper 30, a one-component developer 31 made of non-magnetic component toner is accommodated.

A developing sleeve 32 serving as a developer carrying member is rotatably disposed in an opening part of the hopper 30 on the photosensitive drum 11 side.

0 Further, a developer supply roller 34 for supplying the developer 31 to the surface of the development sleeve 32 is rotatably arranged on the side of the development sleeve 32, and this developer supply roller 34 is rotated as shown by the arrow. This is for supplying the developer 31 to the surface of the developing sleeve 32 by rotating in the direction.

Furthermore, the developer 31 supplied to the surface of the developing sleeve 32 as described above is triboelectrically charged by the layer thickness regulating member 35 and is formed into a thin layer.

The developer 31 formed in a layer on the developing sleeve 32 is transported to the vicinity of the photosensitive drum 11 as the developing sleeve 32 rotates. Developer flying gap 36 between
At this time, the developing sleeve 32 flies back and forth between the developing sleeve 32 and the photoreceptor drum 11 due to the alternating electric field formed by the developing bias obtained by superimposing the AC voltage on the DC voltage applied to the developing sleeve 32, and the above-mentioned particles are applied to the surface of the photoreceptor drum 11. Develop the electrostatic latent image formed as described above.

By the way, the developing device according to this embodiment has, in addition to the above-mentioned configuration 1, a small developer scattering prevention electrode installed near the downstream side of the developer flying region between the latent image carrier and the developer carrier. , is configured to apply a predetermined bias voltage to this developer scattering prevention electrode.

That is, on the downstream side of the developer flying gap 36 between the photoreceptor drum 11 and the developing sleeve 32 (as shown in FIG.
A predetermined bias voltage is applied to this one Noyer electrode 37 by a power source 38. The voltage applied to the wire electrode 37 is determined by taking into account the amount of Teiden of the developer 31, etc., but if the developer 31 is composed of negatively charged 1 to ner, for example, the voltage applied to the developing sleeve 32 is determined. When the DC voltage is -100V, it is set to about -200V.

The power source 38 may of course be newly installed, but for example, an electric wire for applying a voltage to the electrical appliance 12 or the developing sleeve 32 may be provided around the hole.

At this time, the gaps dl and d2 between the wire electrode 37 and the photoreceptor drum 211 and the developing sleeve 32 are set larger than the gap d between the photoreceptor drum 11 and the developing sleeve 32. This prevents discharge from occurring between the body drum 11 and the developing sleeve 32.

In the developing device according to the above-mentioned second configuration, the occurrence of developer scattering etc. is prevented in the following manner. That is, the photoconductor tram 11 is
When developing the electrostatic latent image formed in step 2, when the developer 31 carried on the surface of the developing sleeve 32 flies in the developer flying region 36, air is generated due to the rotation of the photoreceptor drum 110, etc. The developer 31 that flies due to the flow is scattered to the outside of the developing device 25.

However, a wire electrode 37 is located near the downstream side of the developer flying region 36 between the photoreceptor drum 11 and the developing sleeve 32.
A predetermined bias voltage having the same polarity as the designated polarity of the developer 31 is applied to the wire electrode 37 by the 'ji source 38, so that the photosensitive drum 11 and the developing sleeve 332 are The developer 31 that tries to scatter to the outside from the developer carrier [ 36 between them is repelled by the electric field created by the wire electrode 37 and returned to the developing sleeve 32 side. Developing device 2
The developer 31 is collected inside the developing device 25, and scattering of the developer 31 from the developing device 25 is fundamentally prevented.

Therefore, not only can the interior of the copying machine be prevented from being contaminated by the developer scattered from the developing device 25, but also the developer 31 receives a repulsive force due to the electric field created by the wire electrode 37. Since the developer reliably returns to the inside of the developing device 25, the collected developer does not accumulate on a part of the developing device and cause any inconvenience.

FIG. 4 shows another embodiment of the developing device according to the present invention, and the same parts as in the above embodiment are denoted by the same reference numerals (
= j b In this embodiment, the flying developer is placed near the downstream side of the developer flying region between the latent image carrier and the developer carrier, and an airflow generating device is used to generate an airflow that guides the flying developer into the inside of the “9”. The structure is being ordered to construct a bridge.

That is, on the downstream side of the developer flying gap 36 between the photosensitive drum 11 and the developing sleeve 32, as shown in FIG. I'm here. This airflow generating section 040 is the fifth
As shown in the figure, the photoreceptor drum 11 and the developing sleeve 32
The air flow generated by the rotation of the developer is divided into parts, and the divided air flow has the effect of returning the scattered developer 31 generated in the developer flying area 36 to the developing sleeve 32 side or the photosensitive drum 11 side.

In this way, the airflow generating member 40 generates an airflow that guides the flying developer 31 into the apparatus near the downstream side of the developer flying region 36 between the photoreceptor drum 11 and the developing sleeve 32.
Since the developer 31 that is about to be scattered outside from the developer flying area 36 between the photoreceptor drum 11 and the developing sleeve 32 is returned to the inside of the device 25 by the air flow generating member 40, and the developing agent 31 is The scattering of the agent 31 is fundamentally prevented.

5 Since the other configurations and functions are the same as those of the above embodiment,
The explanation will be omitted.

FIG. 6 shows still another embodiment of the developing device according to the present invention, and the same parts as in the above embodiment are given the same reference numerals. In this embodiment, the latent image carrier is An airflow generating member, which has at least a conductive surface and generates an airflow that guides the flying developer into the device, is installed near the downstream side of the developer flying region between the developer carrier and the developer carrier. It is configured to apply a predetermined bias voltage to the generating member.

That is, on the downstream side of the developer flying gap 36 between the photosensitive drum 11 and the developing sleeve 32, as shown in FIG. ing. As shown in FIG.
The air flow generated by the rotation of the drum 2 is divided into parts, and the divided air flow returns the scattered developer 31 generated in the developer flying area 36 to the developing sleeve 32 side or the photoreceptor drum 11 side. affect

Further, the airflow generating member 40, as shown in FIG.
It is composed of a base material 40a for an airflow generating member made of an insulating member, and a conductive material 140b coated on the surface thereof.
A predetermined bias voltage is applied to this conductive layer 40b by a power source 41. The voltage applied to the conductive layer 40b of the airflow generating member 40 is determined by taking into consideration the teironic current of the developer 31, but when the developer 31 is made of negatively charged toner, for example, -100 ~1000
VPi! set at the same time. Note that the power source 38 may of course be newly provided, but for example, a power source that applies voltage to the -order charger 12 or the developing sleeve 32 may be used.

At that time, the gaps dl and d2 between the conductive layer 40b of the airflow generating portion U3O, the photoreceptor drum 11, and the developing sleeve 32 are
As in the embodiment described above, is set larger than the gap d between the photoreceptor drum 11 and the developing sleeve 32, and the discharge occurs between the wire electrode 37 and the photoreceptor drum 11 and the developing sleeve 32. is prevented.

In this way, the airflow generation section 40 that generates an airflow that guides the flying developer 31 into the apparatus is installed near the downstream side of the developer flying region 36 between the photoreceptor drum 11 and the developing sleeve 32.
Since the developer 31 is constructed such that the developer 31 is scattered outside from the developer flying region 36 between the photoreceptor drum 11 and the developing sleeve 32, it is returned to the inside of the device 25 by the air flow generator 40. The scattering of the developer 31 is fundamentally prevented.

Further, in this embodiment, in addition to the above-mentioned effect, the developer 31 is applied to the conductive layer 40b of the airflow generating part 40 by the power source 41.
Since a predetermined bias voltage having the same polarity as the charging polarity of Because it is repelled by the electric field created by the conductive layer 40b of 40 and returned to the developing sleeve 32 side,
The developer 31 is collected inside the developing device @25 as the developing sleeve 32 rotates, and scattering of the developer 31 from the developing device 825 is fundamentally prevented.

Other configurations and functions are the same as in the previous embodiment, so
The explanation will be omitted.

In the above embodiments, the developing device employs a jumping developing method using a non-magnetic component developer, but is not limited to this, and may include a magnetic component developing method, a two-component magnetic brush, etc. Of course, the present invention can also be applied to an apparatus using a developing method.

[Effects of the Invention] The present invention has the above-described configuration and operation, and in the developing device according to claim 1, there is provided a developing device in the vicinity of the downstream side of the developer flying region between the latent image carrier and the developer carrier. , a small developer scattering prevention electrode is installed and a predetermined bias voltage is applied to this developer scattering prevention electrode.
The developer that is about to scatter to the outside from the developer flying area between the latent image carrier and the developer carrier is repelled by the electric field created by the developer scattering prevention electrode and returned to the inside of the developing device. , it is possible to fundamentally prevent developer scattering.

Further, in the developing device according to claim 2, an air current that generates an air flow that guides the flying developer into the device is provided near the downstream side of the developer flying region between the developer carriers such as the latent image carrier. Since the generation member is constructed to be installed, the developer that scatters to the outside from the developer flying area between the latent image carrier and the developer carrier is returned to the inside of the apparatus by the air flow generation member. It is possible to fundamentally prevent developer scattering.

Furthermore, in the developing device according to claim 2,
33. At least the surface has conductivity near the downstream side of the developer flying region between the latent image carrier and the developer carrier, and the developer flies.33. ! An airflow generating member that generates an airflow that guides the developer into the apparatus is installed, and a predetermined bias voltage is applied to this airflow generating member, so that the latent image carrier and the developer carrying member are connected to each other. The developer that is about to scatter outside from the developer flying area between the bodies is returned into the equipment by the airflow generating member, and is also repelled by the electric field created by the airflow generating member and returned to the inside of the developing device. , it is possible to fundamentally prevent developer scattering.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the developing device according to the present invention, FIG. 2 is an explanatory diagram of the main parts of the developing device, and FIG. 3 is an electrophotographic copying machine to which the developing device according to the present invention can be applied. FIG. 4 is a main part configuration diagram showing another example of the actual flow of this invention.
Fig. 5 is an explanatory diagram showing the operation of the same embodiment, Fig. 6 is a block diagram showing still another embodiment of the present invention, Fig. 7 is a block diagram of the main part of the same embodiment, and Fig. 8 is the same. An explanatory diagram showing the effect of the embodiment,
FIG. 9 is a sectional view showing an airflow generating member, and FIG. 10 is an explanatory view showing a conventional developing device. [Explanation of number 5] 11... Photosensitive drum 25... Developing device 31... Developer 32... Developing sleeve 37... Wire electrode 38... Bias power source 40... Air flow generation Parts patent applicant: Fuji Pi1 Cox Co., Ltd.
Attorney Patent Attorney Tomohiro Nakaso (1 other person) 1 2 Figure 4 Figure Figure Figure 8 Figure Figure 0a

Claims (3)

[Claims] (1) In a developing device that visualizes an electrostatic latent image formed on a latent image carrier by flying developer held around the developer carrier, the latent image carrier and the developer A developing device characterized in that a small developer scattering prevention electrode is installed near the downstream side of a developer flying region between agent carriers, and a predetermined bias voltage is applied to this developer scattering prevention electrode. (2) In a developing device that visualizes an electrostatic latent image formed on a latent image carrier by flying developer held around the developer carrier, the latent image carrier and the developer A developing device characterized in that an airflow generating member for generating an airflow that guides flying developer into the device is installed near the downstream side of a developer flying region between developer carriers. (3) In a developing device that visualizes an electrostatic latent image formed on a latent image carrier by flying developer held around the developer carrier, the latent image carrier and the developer An airflow generating member having at least a conductive surface and generating an airflow that guides the flying developer into the device is installed near the downstream side of the developer flying region between the agent carriers, and this airflow generating member A developing device that applies a predetermined bias voltage to.