JPH02287471A - Developing device - Google Patents

Abstract

PURPOSE:To prevent the contamination of a device by setting the pressing force of side seal members in which the pressure of a leakage prevent sheet is higher than that of the central part at the prescribed pressure so that a space is not created between a developer carrier and the leakage preventing sheet. CONSTITUTION:The pressure of the leakage preventing sheet 58 slightly coming into contact with the peripheral surface of the developer carrier 29 in which the pressing force of side seal members 48 and 49 is higher than that of the central part is set at the prescribed pressure so that a space is not created between the developer carrier 29 and the leakage preventing sheet 58 owing to the deformation of the leakage preventing sheet 58. Thus, the leakage preventing sheet 58 prevents the leakage of developer from the space between the developer carrier 29 and a developing container 39, and the leakage of the developer from the developer carrier 29 and both edges of the leakage preventing sheet 58 can be prevented by the side seal materials 48 and 49. Therefore, the contamination of the device can be prevented, and high quality developing can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a toner seal for a developing device used in a copier, printer, etc. that applies electrophotography, and more specifically, toner seals for toner seals in developing devices used in copying machines, printers, etc. that apply electrophotography. The present invention relates to a developing device that prevents leakage of developer.

BACKGROUND ART Conventionally, in a one-component developing device, if developer leaks, it will have negative effects on the main body of the device such as developer scattering and contamination. is shown in Fig. 7.
In the device described in Japanese Patent No. 9, a leak-preventing elastic body 2 made of felt is pressed against the outer circumferential surface of both ends of the developing roller 1.

Regarding the leakage in the central part of the developer carrier, in the one described in Japanese Patent Laid-Open No. 82-27770 shown in FIG. 8, a sealing member 6 is provided in the gap 5 between the developing roller 3 and the developing container 4, A member 6 is used in which one end is fixed to the developer container 4 and the other end is in contact with the outer peripheral surface of the developer roller 3. Such prevention means can only prevent leakage.

The inventors of the present application filed a patent application in 1983 for a means to solve both of these problems.
It was proposed in No. 80851.

FIG. 9 is a block diagram showing an example of a one-component developing device according to this proposal. This structure includes an elastic leak-prevention sheet 9 that has one end fixed to the developer container 8 and the other end of which seals a gap A between the developer roller 7 and the developer container 8 by applying a light liquid to the outer peripheral surface of the developer roller rough; A side seal member lO that surrounds both ends of the outer circumferential surface of the developer roller 7 and tightly adheres thereto to prevent leakage of developer from the ends; Narrowing member 1 that fills the gap
It consists of 1.

Problems to be Solved by the Invention However, the configuration shown in FIG. 9 causes the following problems depending on the conditions of the developing roller 7, the leak prevention sheet 9, and the constriction member 11.

(1) As shown in FIG. 1O, the width of the leak prevention sheet 9 is larger than the width of the developing roller 7, and the narrowing member l! When it protrudes outward from the end surface of the developing roller 7, both ends are bent as shown by B. Therefore, the tension on the center side of the leak prevention sheet 9 changes due to the bending, and as shown in the figure, a gap δ is partially generated between the developing roller 7 and the leak prevention sheet 9, causing toner leakage.

(2) If the pressure of the constriction member 11 that presses the surface of the developing roller 7 through the leak prevention sheet 9 becomes excessively high, the tension at both ends of the leak prevention sheet 9 becomes greater than the tension at the center, and as shown in Fig. 1θ, the developing roller 7 A gap δ is generated between the toner and the leakage prevention sheet 9, resulting in toner leakage.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a developing device that can solve these conventional problems, eliminate contamination of the device, and form high-quality images.

Means for Solving the Problems The technical means of the present invention for solving the above-mentioned problems is to provide an endless developer carrier and regulate the developer on the developer carrier to a predetermined layer thickness. a layer thickness regulating means; an elastic leak-prevention sheet having one end fixed to the developer container and the other end applying a light liquid to the outer peripheral surface of the developer carrier to seal the gap between the developer carrier and the developer container; and a side seal member made of an elastic body that surrounds both ends of the outer circumferential surface of the developer carrier and the surface of the leakage prevention sheet in the container and tightly contacts them to prevent leakage of the developer from the ends. The pressure of the leak prevention sheet on the side where light liquid is applied to the outer circumferential surface of the carrier is higher on the side seal member side than the center part, and the pressure of the side seal member is higher than that of the developer carrier due to the deformation of the leak prevention sheet. This is set at a predetermined pressure that does not create a gap with the leak prevention sheet.

For production The effect of this technical means is as follows.

That is, the layer thickness regulating means regulates the layer thickness of the developer on the developer carrier and charges the developer. The pressure of the leak prevention sheet on the side where light liquid is applied to the outer circumferential surface of the developer carrier is higher than that of the center on the side seal member side, and the pressing force of the side seal member is due to the deformation of the leak prevention sheet. The pressure is set to a predetermined pressure that does not create a gap between the developer carrier and the developer container. It is possible to prevent developer from leaking from both ends of the carrier and the leak prevention sheet.

As a result, contamination of the apparatus is eliminated and high-quality image development becomes possible.

EXAMPLE A developing device in an example of the present invention will be described below. FIGS. 1 to 8 show the developing device of this embodiment, which is an example of use in an electrophotographic copying machine.

In FIG. 1, reference numeral 22 denotes a charge carrier, such as electrostatic recording paper or a photosensitive drum. In this embodiment, the charge holding body 22 is a photosensitive drum (therefore, hereinafter, the charge holding body 22 will be referred to as a photosensitive drum 2).
2), a photoconductor 24 such as zinc oxide, selenium, organic photoconductive material, etc.
It carries the following. Reference numeral 25 denotes a charger which charges the entire surface of the photoconductor 24 by applying a negative corona in the case of zinc oxide and a positive corona in the case of selenium, depending on the photoconductor 24 on the photosensitive drum 22 by the first DC high voltage power supply 2B. It is something that makes you

Reference numeral 27 denotes an optical section that projects a patterned optical image onto the photosensitive drum 22 to form an electrostatic latent image. A developer 28 is a normal one-component insulating toner. Note that the developer 28 may be a magnetic toner or a non-magnetic toner.

Reference numeral 29 denotes a developing roller which is a developer carrier. For example, a metal roller made of stainless steel or aluminum, a roller whose surface is coated with resin, etc. are used. Preferably, as shown in FIG. The outer circumferential surfaces 29a and 29b at both ends are smooth, and the center surface 29c has a rough surface with minute irregularities, and is installed at a constant distance from the photosensitive drum 22, for example, in a counterclockwise direction as shown in FIG. Rotate it.

Reference numeral 30 denotes a cylindrical elastic body that supplies the developer 28 to the developing roller 29. The cylindrical elastic body 30 is a fur brush, a roller made of sponge, etc.
2 layers are formed. In this embodiment, a cylindrical elastic body 3
0 is a fur brush, and the elastic material 32 is made of conductive fur using carbon-containing rayon fiber. Further, the fur brush 30 is surrounded by a developing container 33,
It is in sliding contact with the surface of the developing roller 29 and rotated, for example, in a clockwise direction. Reference numeral 34 denotes a developer storage means, which is composed of a storage section 35 that stores the developer 28 and a supply means 36 that supplies the developer to the fur brush 30. Further, the storage section 35 has an opening 37 for replenishing the developer 28 at one end, and is formed by a part of the developer container 33 . Further, the supplying means 3B fixes one end of a sheet-like elastic member 38 made of polyethylene terephthalate or the like with a thickness of about 30 to 80 μm to the outer peripheral surface of the mandrel 38, and rotates or swings the mandrel 38 to remove the developer 28. is supplied to the fur brush 30. In this embodiment, the mandrel 38 rotates clockwise. Reference numeral 40 denotes a partition plate serving as a circulation means, which is provided between the fur brush 30 and the supply means 3B, and has an opening 41 through which the developer 28 flows in and out between the fur brush 30 and the supply means 36. 42 is a scraping plate formed by a part of the developing container 33, and a fur brush 3.
0 to make the amount of the developer 28 in the fur brush 30 uniform and to remove the overcharged developer 28 in the fur brush 30.
It scrapes off. 43 is a lid of the replenishment opening 37. A developer reservoir 44 is provided on the fur brush 30 between the developer roller 29 and the supply means 36.

The developer reservoir 44 has a capacity that can supply a predetermined amount of developer 28 to the fur brush 30. As shown in FIG. 2, 45 is the bearing of the developing roller 29, and 46 is the fur brush 3.
0 bearing. Reference numeral 47 denotes a layer thickness regulating means for regulating the layer thickness of the developer 28. In this embodiment, a plate-shaped elastic blade made of urethane rubber is used, but other rubber materials, polyethylene terephthalate, etc. may be used as the elastic blade material. It may be made of an elastic synthetic resin, an elastic metal such as phosphor bronze, or spring steel, or an elastic metal or synthetic resin coated with a fluororesin. The width of the elastic blade 47 is set to such a length that it comes into contact with the outer circumferential surfaces 29a and 29b at both ends of the developing roller 29, as shown in FIGS. 2 and 3. In FIGS. 2 to 4, 48.49 is the developing roller 29.
A side seal member made of an elastic material that surrounds the outer circumferential surfaces 29a and 29b at both ends and closes thereto to block the developer 28 moving to both ends. It is made of elastic material. 5
0. 51 is the developing roller 23 and the side seal member 48.
49 and the elastic blade 47, and is made of an elastic material such as sponge or rubber.

Elastic sheets 52 and 53 further block the developer 28 moving to both ends, and are made of an elastic material such as polyethylene terephthalate or metal having a diameter of 40 to 150 μm. In addition, the elastic seams 52 and 53 have one end connected to the side seal member 48. 49, the other end protrudes downstream from the blade edge 47A with respect to the rotating direction of the developing roller 29, and is provided between the developing roller 2B and the sealing material 50°51. 54. Reference numeral 55 denotes a presser plate spring that improves the adhesion of the elastic blade 47 to the developing roller 29, and is provided by pressing the sealing material 50.51 and the elastic sheets 52 and 53 through the elastic blade 47.

56 is a means for preventing the developer 28 from spilling to seal the gap A between the developing roller 29 and the developing container 33;
The developing roller 23 and the fur brush 3
0 and below the developing roller 2B. Further, the spill prevention means 56 has a U-shaped leak prevention member 57, and one end is fixed to the leak prevention member 57.
The other end is constituted by an elastic leak-prevention sheet 58 that spreads liquid onto the surface of the developing roller 29. In addition, spill prevention means 5B
One end of the leakage prevention sheet 58 may be provided on the developer container 33. A gap between both ends of the leak prevention sheet 58 in the width direction and the developer container 33 is provided by the side seal member 48. The lower part of 49 is in close contact with them to form a seal. Also,
Since the deformation of both ends of the leak prevention sheet 58 affects the leakage of the developer 28, as shown in FIG. and outer circumferential surfaces 29a at both ends of the developing roller 29,
29b, or as shown in FIG. 49 is preferably provided inside the width of the developing roller 29.

As shown in FIGS. 5 and 6, side seal members 48, 4
9 is opposed to the smooth surfaces of the outer circumferential surfaces 29a and 29b at both ends of the developing roller 29, and is pressed against the developing roller 29 through a leak-preventing sheet. By pressing against a smooth surface, wear on the surface of the leak prevention sheet 58 can be reduced, and the tension at both ends of the leak prevention sheet 58 can be stabilized. The line pressure of the leak prevention sheet 58 on the side where light liquid is applied to the outer peripheral surface of the developing roller 29 is such that the line pressure WB at both ends is higher than the line pressure WA at the center, and the pressing force of the side seal members 48 and 49 is higher than the line pressure of the leak prevention sheet 58. 58
The pressure is set at a predetermined pressure that does not cause a gap δ as shown in FIG. 1O to occur between the developing roller 29 and the leakage prevention sheet 58 due to deformation. This predetermined pressure varies depending on the material, thickness, etc. For example, when the material of the leak prevention sheet 58 is a urethane sheet and the thickness is 100 μm, the leak prevention sheet 58
It is preferable to press the side seal members 48 and 49 so that the tension at both ends of the tip of the holder 8 is about 100 lb or less. Further, the end of the leak prevention sheet 58 on the side where the liquid is lightly applied to the surface of the developing roller 29 is provided so as not to be located on the contact surface between the developing roller 29 and the fur brush 30. In addition, leak prevention sheet 58
An elastic material such as polyethylene terephthalate or urethane rubber is used in this embodiment.
m) is used. The leak prevention member 57 is made of metal such as stainless steel or aluminum, and prevents the developer 28 from falling downward even if it leaks from the gap between the developing roller 29 and the leak prevention sheet 58.

In this case, since leakage of the developer 28 is almost completely stopped by the leakage prevention sheet 58, the capacity of the leakage prevention member 57 may be small.

As shown in FIG. 1, BO is a second DC high-voltage power supply that is an application means for applying voltage, and applies a voltage between the developing roller 29 and the fur brush 30 to charge the surface of the developing roller 29. This is to adjust the layer thickness of the developer 28. Further, although the applying means 60 uses a DC bias voltage in this embodiment, a voltage obtained by superimposing an AC voltage on a DC voltage may also be used. By using a conductive material, the fur brush 30 has the function of preventing overcharging of the frictionally charged developer 28 on the developing roller 2B and making the potential uniform. Therefore, the fur brush 30 has a specific resistance of about 101aΩCl11 or less, and a good mashikuha 102
It is better to use a conductive material with ΩC11 to 107ΩCI.

In addition, the fur brush 30 is not only made of conductive rayon fibers as in this embodiment (it may also be made of other conductive fibers, or it may be made of electrostatic flocking to make the coating uniform). It is also effective to use a fur brush.

Furthermore, it goes without saying that the above-described effects of frictional charging, coating, etc. can be effectively performed even if a conductive sponge, conductive cloth, or soft wire brush is used as the elastic material 32 of the cylindrical elastic body 30. Incidentally, when the developer 28 is a one-component magnetic toner, it is also effective to use a magnetic roller as the mandrel 31 and form a magnetic brush on the outer periphery thereof to form the cylindrical elastic body 30.

The operation of the developing device of this embodiment configured as described above will be explained. Here, in order to make the operation easier to understand, the photoconductor 24 on the photosensitive drum 22 is made of zinc oxide, and the cylindrical elastic body 30 is made of an elastic material 3 on an aluminum core 31.
2 is a fur brush with carbon-containing rayon fibers with a specific resistance of about 106 Ωcm flocked at a rate of about 3600 fibers/am2, and a developing roller 29) Surface roughness is 5 μm Rwax
, the linear pressure of the elastic blade 47 in pressure contact with the developing roller 28 is 25 g/am, the gap between the photosensitive drum 22 and the developing roller 29 is 0.15 mm, and the developer 28 is a normal positively charged non-magnetic one-component toner. We will explain the case where we conducted an experiment.

In FIG. 1, the charger 25 is connected to a first high-voltage DC current [2B
A high voltage of about -8 kV is applied to the photosensitive drum 22, and the entire surface of the photosensitive drum 22 is negatively charged to about -600 V by a negative corona. Next, if a reflected image (pattern light image) of the document irradiated with a halogen lamp or the like is projected by the optical section 27 onto the negatively charged photosensitive drum 22, the photosensitive drum 22
The portion corresponding to the non-image portion of the upper document is neutralized by the reflected light to a residual potential close to OV, forming a positive electrostatic latent image.

During this time, the developer 28 in the storage section 35 is uniformly supplied to the developer reservoir 44 through the opening 41 by the sheet-like elastic member 39. Next, the uniformly supplied developer 29 is supplied into the fur brush 30. Next, the excess developer in the fur brush 30 is scraped off by a scraping plate 42 and supplied in an appropriate amount, and is positively charged by friction with the scraping plate 42 and the developer container 33. Next, an electric field is generated between the developing roller 29 and the fur brush 30 by the charged developer 28 in the fur brush 30, and the surface of the developing roller 29 is coated with the charged developer 28. At this time, a voltage of about 0 to 250 V is applied from the second DC high voltage power supply 60 to adjust the layer thickness. Furthermore, by applying this voltage, when the developer 28 is transferred from the fur brush 30 to the developing roller 23, even if there is, for example, uncharged developer 28 or developer 28 charged with the opposite sign in the developer 2 days, the developer 28 remains uncharged. The developer 28 charged with the opposite sign is difficult to be transported, and only the normally charged developer 28 is selected and contributes to development.

Therefore, the developing roller 29 is coated with the uniformly charged developer 28, and a high quality image can be obtained. Here, the layer thickness of the developer 28 on the coated surface of the developing roller 29 is greater than a predetermined thickness, and there is some variation. Next, developing roller 2
When the charged developer 28 on the surface of the developing roller 29 passes through the elastic blade 47, a part of it is scraped off by the elastic blade 47, resulting in a predetermined layer thickness of about 40 μm (the layer thickness at this time is 10 μm). (preferably about 70 μm) and is further charged.

Next, the developer 28 that has come into contact with the elastic blade 47 falls onto the fur brush 30 while moving from the center of the developing roller 23 toward both ends. Next, the developer 28 that has moved toward both ends of the developing roller 29 is transferred to the side seal members 48. 48
and sealing material 50. 51 and elastic sea) 52. Since the developing roller 29 has a sealed structure in which the outer circumferential surfaces 29a and 29b at both ends are surrounded by the developer roller 53, there is no scattering or leakage of the developer 28. That is, the developing device of this embodiment can uniformly charge the developer 28 on the developing roller 2B, and can also make the layer thickness uniform.Furthermore, there is no scattering or leakage of the developer 28, and there is no fogging or density. It is possible to obtain high-quality images without unevenness.

Next, when the negatively charged electrostatic latent image on the photosensitive drum 22 faces the positively charged developer 28 on the developing roller 28, the developer 28 is blown away by the electrostatic force of the electrostatic latent image on the photosensitive drum 22. The latent image can then be developed. Surplus developer 28 that was not used for development is transferred to the developing roller 2.
While still attached to B, it is carried further downstream and passes through the leakage prevention sheet 58. At this time, since the leakage prevention sheet 58 is lightly liquid on the developing roller 29, the developer is carried as it is into the developer container 33 by electrostatic adhesion, and after passing through the leakage prevention sheet 58, it is returned to the outside. It won't leak. Next, the developer 28 of the developing roller 23 is transferred to the fur brush 3.
It is scraped off by o and conveyed. Next, the developer 28 conveyed by the fur brush 30 is removed from the scraping plate 4.
The developer 28 on the developer roller 29 is not overcharged because the developer 28 is scraped off by the developer roller 29 and returned to the storage section 35 through the opening 41. Therefore, high-quality development is possible. Further, since the developer 28 is stirred within the storage section 35 by the sheet-like elastic member 39, there is an effect that the height of the developer 28 within the storage section 35 is kept constant. Note that since the circumferential speeds of the developing roller 29 and the photosensitive drum 22 are set at the same speed, an edge effect can be produced when the latent image is developed.

In the above embodiment, an example was explained in which regular development (positive-positive development) in an electrophotographic copying machine was tested, but it goes without saying that the present invention can also be applied to reversal development (negative-positive development) in a laser printer or the like. Another book.

The invention is well suited to non-magnetic component developers, and by configuring the charge carrier and developer carrier in a non-contact manner, it is possible to develop color images by overlapping multiple color developers on the charge carrier. It also becomes possible to form

As described in detail, in the present invention, the leak prevention sheet prevents developer from leaking from the gap between the developer carrier and the developer container, and the side seal member prevents the developer from leaking between the developer carrier and the leak prevention sheet. Prevents developer from leaking from both ends.

As a result, the structure is simple, and since the structure is free from leakage of developer and contamination of the device, it is possible to develop high-quality images, and the restrictions on the arrangement of the developing device can be expanded.

[Brief explanation of drawings]

FIG. 1 is a sectional view of essential parts of a developing device according to an embodiment of the present invention, FIGS. 2 to 6 are configuration diagrams of each part of the developing device in the same embodiment, and FIGS. 7 to 10 are conventional FIG. 2 is a sectional view of a main part of a developing device using an example one-component developer. 28...Developer, 29...Developer carrier, 33...
・Developer container, 47...Layer thickness regulating means, 48.49...
- Side seal member, 58...Leakage prevention sheet. Name of agent: Patent attorney Shigetaka Awano et al. 18th ε-* Tortoise removal am 躬旬 Asahi binding stop 1 --- H platform Yong Lu 47 -- Layer thickness jl tough hand pickled milk -- 111 prevention sheet 29 --! Electric cut shell monument Stop U-・-Currently 1m g@Totsutsu3zu-m- 8--147-・- #, +9-- 3-・N, Tortoise 'B μtsu? Tom it yong Lu layer thickness regulation means Zydo seal viJ village leak) INF8 stop sheet stolen 5 Figure --- Q, 49 --- Leap --- A --- e --- 1! It 1M straddle side seal hitting; 9th line pressure fi & wholesale line pressure in 1st prevention sheet 6 Fig. 10

Claims (1)

[Claims] An endless developer carrier, a layer thickness regulating means for regulating the developer on the developer carrier to a predetermined layer thickness, and a layer thickness regulating means for regulating the developer on the developer carrier to a predetermined layer thickness. A leak prevention sheet made of an elastic material that seals the gap between the developer carrier and the developer container in contact with each other; and a side seal member made of an elastic body that prevents developer from leaking from the edge.The pressure of the leak prevention sheet on the side that lightly contacts the outer circumferential surface of the developer carrier is applied from the center to the pressed part of the side seal member. A developing device characterized in that the pressing force of the side seal member is set to a predetermined pressure that does not cause a gap between the developer carrier and the leak prevention sheet due to deformation of the leak prevention sheet.