JPH09156150A - Developing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sustain a magnetic toner layer held on the circumferential surface of a feed roller surely at a constant thickness by interposing a sheet member for touching the surface of magnetic toner layer lightly to sustain a constant thickness between a regulation member and a magnetic toner supply region. SOLUTION: The developing system 38 comprises a housing 48, a roller 50 for feeding a magnetic toner 66 to a magnetic drum 28 in a magnetic toner supply region, and rollers 52, 54 for transporting the magnetic toner 66 to the feed roller 66. The feed roller 50 holds the magnetic toner 66 as a layer on the circumferential surface thereof while spacing apart from the magnetic drum 28. A regulation member 60 for sustaining the magnetic toner layer at a constant thickness is disposed at an upstream position in the supply region with one edge part thereof being spaced apart from the circumferential surface of feed roller 50 by a specified distance corresponding to a desired thickness of toner layer. A thin film 62 is interposed between the regulation member 60 and the supply region in order to sustain the constant thickness of magnetic toner layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device, and in particular, in a developing area of a magnetic printing device, a developing toner of a proper thickness is always supplied to a magnetic recording medium to enable high quality developing without fog. The present invention relates to a developing device.

[0002]

2. Description of the Related Art There is known a magnetic printing apparatus capable of printing a required number of copies by forming a latent image once. In the developing device of this magnetic printing apparatus, a magnetic latent image magnetically formed on a magnetic recording medium is held, and magnetic toner is supplied to the magnetic recording medium in the developing area to visualize the magnetic latent image and transfer it. By pressing the image carrier such as paper against the magnetic recording medium in the area, transfer the visualized toner image to the image carrier, and further convey the image carrier after transfer to the fixing area for fixing processing. Complete the print. The magnetic latent image can be easily formed and erased magnetically, and a printing plate is unnecessary, so that the cost is reduced. The magnetic toner is supplied by a supply roller arranged at a position separated from the magnetic recording medium. The supply roller holds the magnetic toner layer on its peripheral surface and brings the magnetic toner layer into contact with the magnetic recording medium to supply the magnetic toner to the magnetic latent image on the magnetic recording medium.
Attach it.

In a magnetic printing apparatus, it is necessary to uniformly supply and attach a desired amount of magnetic toner to a magnetic recording medium in order to obtain a good image transferred to an image carrier. For example, when the amount of magnetic toner supplied to the magnetic recording medium is too large, the magnetic toner adheres to the portion other than the magnetic latent image, and the magnetic toner adheres to the image carrier from the magnetic recording medium. Phenomenon occurs. On the other hand, when the amount is too small, a sufficient amount of magnetic toner does not adhere to the magnetic latent image, resulting in a decrease in print density, which is a so-called “scatter phenomenon”. Therefore, keep the magnetic toner layer thickness constant,
It is necessary to maintain a constant contact area (magnetic toner supply area) where the magnetic toner layer held by the supply roller contacts the magnetic recording medium. Therefore, conventionally, a restricting member is provided that extends in the axial direction of the supplying roller and substantially the entire width of the supplying roller, and the restricting member is arranged apart from the peripheral surface of the supplying roller by a predetermined distance corresponding to a desired magnetic toner layer thickness. There is. That is, the magnetic toner layer portion exceeding the desired layer thickness is
When passing through a space formed between the supply roller and the lower edge portion of the regulating member, the magnetic toner layer is scraped off by the lower edge portion of the regulating member, and the magnetic toner layer is maintained at a constant thickness.

[0004]

In the above-mentioned conventional developing device, the magnetic toner layer held on the supply roller cannot be maintained at a desired constant thickness only by the regulating member due to the vibration of the device or the speed fluctuation. there is a possibility. In order to make the magnetic latent image more visible, for example, Japanese Patent Publication No. 55
-17382 and Japanese Patent Publication No. 2-6065, it is disclosed that a weak magnetic field related to the direction of the magnetic field applied to the magnetic recording medium is applied to the contact region. The applied magnetic toner layer rises like a brush outward in the radial direction of the supply roller due to the magnetic field applied in the vicinity of the contact area (magnetic toner supply area), resulting in fluctuation of the magnetic toner layer thickness, and the desired toner layer thickness. May not be maintained.
Therefore, an object of the present invention is to provide a developing device capable of reliably maintaining a constant thickness of the magnetic toner layer held by the supply roller.

[0005]

As a means for solving the above problems, a developing device according to claim 1 of the present invention supplies magnetic toner to a magnetic recording medium holding a magnetic latent image,
In the developing device of the magnetic printing apparatus, which visualizes the magnetic latent image, presses the image carrier onto the magnetic recording medium, and transfers the visualized toner image to the image carrier, A supply roller that is arranged at a distance from the magnetic toner layer, holds the magnetic toner layer on the peripheral surface, contacts the magnetic toner layer with the magnetic recording medium, and supplies and attaches the magnetic toner to the magnetic latent image on the magnetic recording medium. And an edge portion which is arranged at a position upstream of a supply region for supplying the magnetic toner to the magnetic latent image on the magnetic recording medium, and is separated from the peripheral surface of the supply roller by a predetermined distance corresponding to the thickness of the magnetic toner layer. A regulating member for regulating the thickness of the magnetic toner layer on the supply roller, and a magnetic member disposed between the regulating member and the magnetic toner supply region and held on the peripheral surface of the supply roller. By lightly contacting the surface of the toner layer A sheet member for maintaining the magnetic toner layer in a constant thickness state is provided, and the constant thickness magnetic toner layer held by the supply roller is brought into contact with and supplied to the magnetic latent image on the magnetic recording medium. It is the one. With this configuration, the toner layer having a desired layer thickness of the regulation member is pressed by the sheet member under a light pressure, and thus the thickness of the magnetic toner layer is reliably maintained at the desired layer thickness.

The developing device according to claim 2 of the present invention is the developing device according to claim 1.
In the developing device, the magnetic pole is arranged between the regulating member and the supply region. Even after the magnetic toner rises like a brush due to the magnetic pole, the toner layer surface is smoothed by the sheet member, so that the desired toner layer thickness is reliably maintained.

The developing device according to claim 3 of the present invention is the developing device according to claim 1.
Alternatively, in the developing device of No. 2, the sheet member is a thin film having a thickness of 10 to 200 μm. Since such a sheet member is available at a low price and is a thin film, it can be brought into good contact with the magnetic toner layer by light pressure, and the thickness of the magnetic toner layer can be reliably maintained at a desired layer thickness.

According to a fourth aspect of the present invention, there is provided a developing device according to the first aspect.
The developing device according to any one of items 1 to 3, wherein both the sheet member and the regulating member have an edge portion that extends in the axial direction over substantially the entire width of the supply roller. Therefore, the magnetic toner layer held on the supply roller is maintained at a constant thickness over almost the entire width of the supply roller.

[0009]

1 is a general view of a printing apparatus including a developing device of the present invention. In FIG. 1, reference numeral 12 is an image carrier supply unit,
Reference numeral 14 is a fixing unit, and 16 is an image carrier storage unit (hereinafter referred to as a storage unit) arranged downstream of the fixing unit 14. The image carrier is, for example, paper. The storage unit 16 has two mounting tables 20a and 20b of different sizes.
Papers 18a and 18b of different sizes are held on a and 20b, respectively. The paper 18a, 18b is fed from the mounting table 20a or 20b by the paper feed roller 22a or 22b, and is supplied to the transfer unit via the pair of first transport rollers 24a, 24b or the second transport rollers 26a, 26b.

The magnetic printing apparatus has, as a magnetic recording medium, a magnetic drum 28 which holds a magnetic latent image and rotates in the direction of arrow A. As the magnetic recording medium, a film-shaped recording medium may be considered in addition to the cylindrical recording medium such as the magnetic drum 28. Magnetic drum 28 around magnetic drum 28
Transfer roller 30 and cleaning unit 3 in the order of rotation
2, an erasing head 34, a magnetic recording head 36, and a developing device 38 are arranged. The magnetic latent image is magnetically formed on the magnetic drum 28 by the magnetic recording head 36.
The magnetic latent image formed on the magnetic drum 28 is transferred to the developing device 38.
By supplying and adhering the magnetic toner in the magnetic toner supply region of, the image is visualized. Image carrier supply unit 12
The paper 18a or 18b supplied from is pressed against the magnetic drum 28 by the transfer roller 30, and the visualized image is transferred to the paper 18a or 18b. Paper on which the image is transferred 1
8a or 18b is conveyed to the fixing unit 14 via the conveyor belt 40. The paper 18a or 18b is heated in the fixing unit 14 by being passed between the pair of fixing rollers 42a and 42b.
Pressurized, the image is reliably fixed and printed on the paper 18a or 18b. The printed paper 18a or 18b is then transported to the storage unit 16 and stored therein. The magnetic toner remaining on the magnetic drum 28 without being transferred is scraped from the magnetic drum 28 by the cleaning blade 44 of the cleaning unit 32, and the scraped magnetic toner is sucked by the air suction device 46.
Are sucked and removed by and are collected in a filter unit (not shown). On the other hand, the magnetic latent image on the magnetic drum 28 is supplied with magnetic toner again in the developing device 38. The above steps are repeated to print a large number of sheets.

To form a new magnetic latent image, the erasing head 34 erases the magnetic latent image on the magnetic drum 28, and the magnetic recording head 36 forms a new magnetic latent image again.

Next, the developing device 38 will be described in detail. The developing device 38 stores the magnetic toner 66 held in the housing 48 in the magnetic toner supply area (hereinafter, referred to as a magnetic toner supply area).
Supply area. 2), a supply roller 50 for supplying the magnetic toner to the magnetic drum 28, and first and second transfer rollers 52, 54 for conveying the magnetic toner 66 to the supply roller 50. Referring to FIG. 2, which is an enlarged view of the vicinity of the supply region, the supply roller 50 holds the magnetic toner 66 as a layer 58 on the peripheral surface thereof, and is arranged at the separated position from the magnetic drum 28. Further, a regulating member 60 for keeping the layer thickness of the magnetic toner layer 58 constant is arranged at a position upstream of the supply region 56. The regulation member 60 is a generally plate-shaped member that extends over substantially the entire width in the axial direction of the supply roller 50,
The one edge is arranged so as to be separated from the peripheral surface of the supply roller 50 by a predetermined distance corresponding to the desired toner layer thickness. Further, a thin film 62 is arranged as a sheet member that maintains the layer thickness of the magnetic toner layer 58 at a constant thickness between the regulation member 60 and the supply region 56 at a position downstream of the regulation member 60. The thin film 62 extends in the axial direction of the supply roller 50 over substantially the entire width thereof, and the thickness thereof is preferably 10 to 200 μm. One edge of the thin film 62 contacts the magnetic toner layer 58 under a slight contact pressure at a predetermined distance corresponding to the desired toner layer thickness. In this case, the contact pressure may use the elastic force of the thin film 62, and it is not necessary to positively apply pressure from the outside.

The supply roller 50 is internally provided with a plurality of magnetic poles including an S-pole magnetic pole 64a and an N-pole magnetic pole 64b, and these magnetic poles 64a and 64b are fixed so as not to rotate together with the supply roller 50. . One of these magnetic poles 6
4b is arranged especially between the regulating member 60 and the supply region 56. Even if the magnetic toner held on the supply roller 50 rises like a brush due to the magnetic force lines of the magnetic poles 64b, the magnetic toner is better supplied to the magnetic drum 28 while being kept in a predetermined layer thickness by the thin film 62.

In the above magnetic printing apparatus, the supply roller 50
Rotates in the direction of arrow B in the housing 48, and a magnetic toner layer 58 is formed on the peripheral surface thereof. The magnetic toner layer portion having a predetermined thickness or more formed on the supply roller 50 is
It is scraped off when passing through the regulation member 60. Next, when the magnetic toner layer 58 passes through the thin film 62, the thin film 62 makes a slight pressure contact with the magnetic toner layer,
Even if the magnetic toner of the supply roller 50 rises like a brush, the magnetic toner layer is maintained at a constant thickness by the magnetic pole 64b arranged in the supply roller 50. Therefore, the contact width D between the magnetic toner layer 58 and the magnetic drum 28 in the supply region 56,
That is, the area of the supply region is maintained constant, and a predetermined amount of magnetic toner is supplied to the magnetic drum 28. Also thin film 6
Since the magnetic toner layer 58 is kept in a constant thickness by bringing the magnetic toner layer 2 into contact with each other with a slight pressure, the surface of the magnetic toner layer disturbed by the scraping action of the regulating member 60 becomes smooth, and the magnetic toner layer 58 becomes more uniform with the magnetic drum 28. To contact. As described above, by using the regulation member 60 and the thin film 62, the layer thickness of the magnetic toner layer 58 can be regulated easily and inexpensively.

In the above, the embodiment in which the magnetic poles of S pole and N pole are alternately arranged is shown, but this does not limit the present invention, and the same poles (S pole and S pole, or N pole). It is also possible to adopt a form in which the (and north pole) are adjacent to each other.

[0016]

As described above, according to the first aspect of the present invention, since the magnetic toner layer on the supply roller is reliably kept at a constant thickness by the regulating member and the sheet member, a predetermined amount of magnetic toner is transferred to the magnetic drum. It is possible to supply and attach.

According to the second aspect of the present invention, since the magnetic pole is arranged between the regulating member and the magnetic toner supply region, even if the magnetic toner held on the supply roller rises like a brush, the thin film is formed. The magnetic toner is satisfactorily supplied to the magnetic recording medium in the magnetic toner supply area.

According to the third aspect of the present invention, since the sheet member is a thin film, it is easy to bring the sheet member into light contact with the magnetic toner layer.

According to the fourth aspect of the present invention, the regulating member and the sheet member can regulate the layer thickness of the magnetic toner layer over substantially the entire width of the supply roller.

[Brief description of the drawings]

FIG. 1 is an overall view of a printing apparatus including a developing device of the present invention.

FIG. 2 is a diagram showing a magnetic toner supply region of the developing device of the present invention.

[Explanation of symbols]

 18a, 18b ... Paper 28 ... Magnetic drum 50 ... Supply roller 56 ... Supply area 58 ... Magnetic toner layer 60 ... Regulation member 62 ... Thin film

Claims (4)

[Claims] 1. A magnetic toner is supplied to a magnetic recording medium holding a magnetic latent image to visualize the magnetic latent image, and an image carrier is pressed against the magnetic recording medium to form a visualized toner image. In a developing device of a magnetic printing device for transferring to the image bearing member, the magnetic toner layer is arranged at a distance from the magnetic recording medium and at least a magnet is arranged to hold a magnetic toner layer on a peripheral surface, By contacting the magnetic toner layer with the magnetic recording medium,
A supply roller for supplying and adhering magnetic toner to the magnetic latent image on the magnetic recording medium; and a supply roller disposed at an upstream position of a magnetic toner supply area for supplying the magnetic toner to the magnetic latent image on the magnetic recording medium. A regulating member having an edge portion separated from the peripheral surface of the supply roller by a predetermined distance corresponding to the magnetic toner layer thickness, and regulating the magnetic toner layer thickness on the supply roller; the regulating member and the magnetic toner supply region. And a sheet member that is disposed between the magnetic toner layer and a surface of the magnetic toner layer held on the peripheral surface of the supply roller to keep the magnetic toner layer in a constant thickness state by light pressure contact, A developing device, wherein the constant-thickness magnetic toner layer held by the supply roller is brought into contact with and supplied to the magnetic latent image on the magnetic recording medium. 2. The developing device according to claim 1, wherein a magnetic pole is provided between the regulation member and the magnetic toner supply region. 3. The sheet member has a thickness of 10 to 200 μm.
3. The developing device according to claim 1, which is a thin film of m. 4. The developing device according to claim 1, wherein both the sheet member and the regulating member have an edge portion that extends in the axial direction over substantially the entire width of the supply roller.