JPS63316073A - Forming device for toner thin layer - Google Patents

Abstract

PURPOSE:To securely perform the agitation, contact, and electrostatic charging of magnetic carriers and nonmagnetic toner and to separate and convey only the nonmagnetic toner by providing a V-shaped blade oppositely on the upstream side of a developing roller in the conveyance direction of the nonmagnetic toner so that both ends do not contact the roller surface. CONSTITUTION:A magnetic roller 11a is used as a magnetic field producing means which forms the developing roller 11, and a nonmagnetic sleeve 11b and a magnetic roller 11a are rotated; and the nearly V-shaped nonmagnetic blade 12 is arranged in a developer storage container which contains a two- component developer consisting of magnetic carriers and nonmagnetic toner on the upstream side in the nonmagnetic toner conveyance direction so that both ends of the V-shaped blade face the nonmagnetic sleeve surface without contacting,and the nonmagnetic sleeve 11b and magnetic roller 11a are rotated in the same direction. Consequently, the agitation and triboelectrification of the magnetic carriers and nonmagnetic toner are carried out effectively and when the toner is separated from the mixed body of carriers and toner, the carriers are prevented effectively from flowing out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention provides a toner thin layer forming device that is provided with a rotating developing roller in a container that stores a two-component developer. By providing a V-shaped magnetic blade on the side facing each other so that both ends do not contact the roller surface, stirring contact charging between the magnetic carrier of the two-component developer and the non-magnetic toner can be carried out reliably and effectively. In this configuration, only non-magnetic toner is separated and conveyed along with φ.

[Industrial application field]

When non-magnetic toner is supplied to a developing section of an electrophotographic recording device, the present invention ensures and effectively performs stirring contact charging between a magnetic carrier and non-magnetic toner to form only one layer of non-magnetic toner on the surface of a non-magnetic sleeve. - It relates to a toner thin layer forming device that can be conveyed.

[Conventional technology]

Conventionally, in the recording method of a recording device such as a printer using electrophotographic recording or electrostatic recording, for example, in the electrophotographic recording method, a recording drum is provided with a photoconductor film on the surface, and the entire surface is charged, irradiated with one image, developed, transferred, A method in which a series of cleaning steps are performed during one rotation of the recording drum is often used.The problem in the present invention is to use a one-component non-magnetic toner that can supply only non-magnetic toner to the development area in the development process. It is a developing method.

Conventional developing methods include a method in which a sleeve is rotated by a fixed magnetic pole, as shown in JP-A-59-187369, ``Developing Device'', 1% JP-A-60-87549, ``Toner Application Method'', and JP-A-59-87,549, which rotates a sleeve. No. 252570 “Developing device.

JP-A No. 61-29866 "Non-magnetic one-component developing device",
A blade for forming a single layer of toner is pressed against the developing roller as shown in Japanese Patent Application Laid-Open No. 61-29867 "Developing Device Control Method," and the toner is charged between the blade and the developing roller, and the toner is uniformly distributed on the surface of the developing roller 2. A method of forming a thin layer is disclosed. An outline of a recording apparatus using a system (similar to Japanese Patent Application Laid-Open No. 60-87349) in which a two-component developer consisting of a magnetic carrier (ferrite powder, etc.) and a non-magnetic toner is stirred and supplied will be explained below with reference to FIG.

In FIG. 8, the process proceeds by rotating a recording drum 1 consisting of a photoconductive layer 16 formed on a conductive support 1α.

First, the entire surface of the photoconductive film 1b is uniformly charged (41) by the corona charger 2. Next, the charges are selectively removed according to the letter or figure pattern using a semiconductor laser 3 or the like.
An electrostatic latent image 42 is formed. On the other hand, the developing device 5 consists of a fixed magnetic pole 9a and a dielectric sleeve 9b], and the sleeve 9b is rotated in the direction of the arrow as a voltage is applied. container 6
A mixture of magnetic carrier (ferrite powder) and non-magnetic toner is stored in the upstream inlet of the rotating sleeve of the container 6,
A magnetic piece 81 e am for forming a magnetic brush is provided at the downstream outlet. The formation of this magnetic brush and the rotation of the sleeve 9b cause frictional charging and agitation of the magnetic carrier and non-magnetic toner, and the non-magnetic toner adheres to the sleeve 9b by mirror force, and a thin toner layer 73 is formed on the sleeve 9b. The electrostatic latent image 4 of the photoconductive film 1b is transferred by electrostatic force, and the toner adheres to the uncharged portion of the photoconductive film 1b to form a visible image, which is then sent to the omitted transfer section.

After the toner image is transferred to the paper in the transfer section, the photoconductive film 1b is cleaned during a cleaning process.The recording drum returns to its initial state.

[Problem that the invention seeks to solve]

In the method shown in Fig. 8 above, in which the sleeve is rotated using a fixed magnetic pole, the toner and carrier are charged by friction only by the rotation of the sleeve. Therefore, due to insufficient stirring, the toner is not sufficiently charged, and the background of the printed output becomes dark. This may cause stains. In addition, in the method described above in which the toner is charged between the blade and the developing roller by pressing the blade, the trap for sufficiently charging the blade must be held uniformly and accurately on the surface of the developing roller. There is also the problem of blade wear. As described above, in both of the above methods, it is necessary to carry out the stirring at a low speed in order to sufficiently stir and charge the developer, making it difficult to increase the speed.

In addition to the above, in a two-component developer, separation of magnetic carrier and non-magnetic toner may be insufficient, resulting in the risk of outflow of carrier.

An object of the present invention is to ensure that when only non-magnetic toner is supplied to a developing section of an electrophotographic recording device, etc., agitation and contact charging between magnetic carrier and non-magnetic toner can be performed reliably and effectively. It is an object of the present invention to provide a toner thin layer forming device that can reliably separate magnetic carriers.

[Means for solving problems]

In order to achieve the above object, in the present invention, a developing roller consisting of a rotating magnetic aperture roller and a sleeve is provided in a container containing a two-component developer, and a magnetic brush formed by a magnetic carrier is moved, and a non-magnetic toner is moved. In the toner thin layer forming device that forms and conveys a thin layer of on the sleeve, a V-shaped magnetic blade is provided on the upstream side of the developing roller with respect to the non-magnetic toner conveying direction, with both ends of the V-shaped blade not in contact with the roller surface. The magnetic roller and sleeve forming the developing roller are rotated in the same direction (non-magnetic toner conveying direction). A similar magnetic blade may also be provided on the downstream side.

[For production]

The principle of the present invention is shown in Figure 1 (α) to (force).
The two ends of the letter-shaped magnetic blade 12 are arranged to face the developing roller 11 without contacting it. In the figure, when the magnetic roller 211α is rotated, the lines of magnetic force from the magnetic roller 211α are (
α) ~ (Changes sequentially like F).

If there are magnetic poles at both ends of blade 12, the lines of magnetic force will be at blade 1.
2, and if there is a magnetic pole in the center of the blade, magnetic lines of force @ will come out from the top of the blade. At this time, when the carrier is placed on the surface of the sleeve 11b, it is transported clockwise in multiple directions as the magnetic roller rotates.

In the state shown in FIG. 3(α), the lines of magnetic force (2) converge within the blade, and a magnetic brush is formed between the blade end facing the magnetic pole (Ss). Next, in the state shown in FIG. 2(b), the magnetic lines of force @ emerge from the top of the blade, so the magnetic brush moves along the slope of the blade toward the top. Immediately after this, however, the magnetic field lines (2) converge inside the blade as shown in FIG. The magnetic brush separated from the blade is again attracted by the magnetic force of the magnetic roller and returns to the sleeve surface. As described above, carriers are retained in the magnetic blade portion using changes in the magnetic field.

When toner is supplied to this carrier, the toner is triboelectrically charged by the carrier and adheres to the sleeve surface by mirror image force. At this time, if the sleeve 11b is rotated, one layer of non-magnetic toner is conveyed.

In this way, stirring and frictional electrification of the magnetic carrier and non-magnetic toner are effectively performed, and furthermore, when the toner is separated from the mixture of carrier and toner, outflow of the carrier can be effectively prevented.

〔Example〕

FIG. 2 shows an embodiment of a developing machine which is the main part of the present invention. This includes the rotatable sleeve 11b and the magnetic roller 1.
A developing roller 11 made of 1G is provided with a V-shaped magnetic blade 12 with two ends facing each other in a non-contact manner. A developing bias potential Vs is applied to the magnetic roller 11G, and a blade application potential vh is applied to the magnetic blade 12 with respect to the ground potential of the recording drum 1.

Here, the carrier placed near the magnetic blade 12 on the sleeve surface is conveyed clockwise by the rotation of the magnetic row 211α (counterclockwise in the figure), and the magnetic blade is moved by the action explained in FIG. It can be blocked by. Further, the magnetic brush of the carrier causes convection while rotating. At this time, the toner on the surface of the carrier layer is triboelectrically charged and adsorbed,
The magnetic brush becomes the carrier and toner mixing section 16. As this magnetic brush moves over the sleeve surface and advances in the direction of the slope of the magnetic blade, toner adheres to the replacement surface due to image forces. When the blade gap potential Vbg
= VB - If VB is generated, the amount of toner adhering to the sleeve surface increases due to the action of the electric field. In this way, the toner 15 supplied from the toner hopper 14 is sufficiently stirred by convection in the carrier/toner mixing section 16. By rotating the sleeve counterclockwise in the figure, a single layer of Sitna is formed on the sleeve surface and is conveyed as the sleeve rotates. Note that in order to prevent the carrier from flowing out to the downstream part of the carrier and toner mixing section 16,
A carrier outflow prevention blade 13 is provided that suppresses the gap between the blade 1b and the carrier outflow prevention blade 13 to be less than the carrier particle size.

The relationship between the blade gap potential Vby (V) and the concentration (OD) of the toner layer formed on the sleeve surface at this time is shown in FIG. Further, the toner density (OD) also changes depending on the blade gap (am) of the gap between both ends of the magnetic blade 12 facing the sleeve 11bK, and the relationship is shown in FIG.
It was found that m (τpm) should be set to 15007 pm or more in order to prevent carrier outflow (carrier passing under the V-shaped blade).

Further, it was found that the magnetic roller rotation speed Nm had little effect on the density of one layer of toner at this time. The results of this experiment are shown in FIG.

In this way, according to this embodiment, 13 (
It is possible to stably obtain a single layer of toner with a uniform density of about OD). Further, according to the present invention, the toner can be sufficiently triboelectrified by the rotation of the magnetic roller, and the toner concentration (
It was found that more than twice the toner specific charge can be obtained with a two-component developing agent of (wt %).

Further, when development was carried out using the present invention, good recording was possible with a development gap α of 21 m1 or less, an effective latent image strength of 550 V, and a direct current development bias.

FIG. 6 shows the relationship between the development gap and the development density [OD] according to development experiments.

Note that the developing bias potential is not limited to direct current, and may also be an alternating current voltage.

Further, the material of the magnetic blade may be changed to permalloy steel or the like as long as it can achieve the effect explained in FIG. 1.

FIG. 7 shows another embodiment of the present invention. The difference from FIG. 2 is that a carrier outflow prevention blade 21 is provided.

This is the V-shaped magnetic blade 12 in the toner forming section.
Both ends of the same V-shaped magnetic blade are arranged opposite to the developing roller without contacting it. In the embodiment shown in FIG. 2, the gap between the carrier outflow prevention blade and the surface of the developing roller 2 is set to be less than the carrier particle size, but if a V-shaped magnetic blade is used, the same effect as the principle explained in FIG. 1 can be obtained. Changes in the magnetic field can prevent the carrier from flowing out, and the gap between the blade and the developing roller can be made larger than the carrier particle size. In the case of the ferrite carrier with a particle size of 20 μm used in this experiment, even if the gap between the carrier outflow blade and the developing roller surface is made of two sieves, the effect of blocking the carrier can be obtained. In addition,
The gap between the carrier outflow blade and the developing roller is cL5g.
If the amount is less than ml, a layer of toner formed on the sleeve surface may adhere to the carrier outflow prevention blade (current gR).

In order to prevent this, it is sufficient to apply the same potential to the carrier outflow blade as the blade potential applied to the blade of the toner forming section. All you have to do is make it conductive.

〔Effect of the invention〕

As described above, according to the present invention, a V-shaped magnetic blade is provided opposite the toner setting section that sets a layer of toner on the sleeve surface, and the magnetic roller is rotated in the same direction as the sleeve. Contact charging is sufficiently performed by stirring the medium and toner. Furthermore, since there are no sliding parts, there is no need to worry about wear of blades, sleeves, etc.
The carrier and toner are completely separated, and the carrier can be easily prevented from flowing out. As a result, high-speed recording becomes possible.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the principle of the present invention, FIG. 2 is an explanatory diagram of the configuration of an embodiment of the present invention, and FIGS. 3, 4, and 5. FIG. 6 is a characteristic diagram of each element with respect to toner density, FIG. 7 is a configuration diagram of another embodiment of the present invention, and FIG. 8 is an explanatory diagram of a conventional example. 1 is a developing machine, 11 is a developing roller, 11a is a magnetic roller, 116 is a sleeve, 1
2.21 is a V-shaped magnetic blade, 13 is a carrier outflow prevention blade, 14 is a toner hopper, 15 is a toner, 16
1 indicates a carrier toner mixture, and 17 indicates a single layer of nonmagnetic toner.

Claims (2)

[Claims] (1) A developing roller comprising a developer storage container containing a two-component developer consisting of a magnetic carrier and a non-magnetic toner, a magnetic field generating means and a non-magnetic sleeve containing the magnetic field generating means, the surface of the non-magnetic sleeve In the toner thin layer forming apparatus which forms and conveys a non-magnetic toner thin layer, the magnetic field generating means forming the developing roller is a magnetic roller (11a), the non-magnetic sleeve (11b) and the magnetic roller ( 11a) is rotatable, and both V-shaped ends of a substantially V-shaped magnetic blade (12) are arranged opposite to the surface of the non-magnetic sleeve without contacting the surface of the non-magnetic sleeve on the upstream side in the non-magnetic toner conveying direction in the developer storage container; A toner thin layer forming apparatus characterized in that the non-magnetic sleeve (11b) and the magnetic roller (11a) are rotated in the same direction. (2) In the toner thin layer forming apparatus according to claim 1, a similar magnetic blade (12) is provided at the downstream outlet portion of the V-shaped magnetic blade (12) facing the non-magnetic sleeve (11b). A toner thin layer forming device characterized in that a V-shaped magnetic blade is arranged opposite to a non-magnetic sleeve without contacting it.