DE2061666A1 - Cleaning device for cleaning surfaces contaminated with small particles - Google Patents

Description

PATB NTA WWA Γ, Τ DIPL ·. IX-JG. ß. . ρ ί) α υ α s : ί ". ί> PHITIPPINK - WKLi) KTi -HT HASSB Xi 21,175

206166Θ

1.95

Augsburg, December 14, 1970

International Business Machines Corporation, Armonk,

H.Y. 10504, V.St.A.

Cleaning device for cleaning with small ones

Tello.heri contaminated land

The Eri'indum- bet. · Mistaken a cleaning device for cleaning with small T <lent contaminated surfaces, especially for cleaning -ron electrophotographic ^ i'ai'ischen disks, tapes, rolls odor ¹ riergl which for transmission

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a plurality of treatment stations in each case of an image run through, in one of these stations on the relevant electrophotographic plate or the like. Color powder is applied. An essential field of application of the invention is therefore the cleaning of electrophotographic Plates and rollers used in xerography for making copies.

According to the process of electrophotography commonly known as xerography, an electrostatic charge is applied to the surface of a photoconductive member and then exposed through a substantially opaque image so that the electrostatic charge on the surface of the photoconductive member is changed in accordance with that image. In this case, the areas of the photoconductive member exposed to the bright areas of the image are discharged, so that a latent electrostatic image results. Developing said electro static image W is then carried out by means of an electrostatically charged material, ζ .EI. an electroscopic powder which is applied to the surface of the photoconductive part and held there by the charge corresponding to the image. The electrostatically charged material, distributed according to the image, is then transferred to the surface of, for example, a paper or the like

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and on this paper by heat treatment or suitable other means fixed.

The transfer process usually removes only part of the powder at a time, while the rest remains on the photoconductive part. This powder residue must be removed before a new image is developed can be. However, this removal is difficult in that the powder is subjected to an electrostatic charge and any direct contact with the photographic plate will damage the Plate surface can lead, since the currently known photographic materials are not resistant to abrasion.

The aim of the invention is to achieve the object of removing small particles from surfaces without damaging the surface in question in any way. In particular , the invention is intended to remove the remaining material from photoconductive surfaces, for example colored powder, without impairing or damaging the photoconductive surface.

This object is achieved according to the invention by a pressurized gas supply device, furthermore by a device connected to the latter and located close to the surface to be cleaned.

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arranged or to be arranged nozzle arrangement with a plurality of individual nozzles, the latter being arranged in such a way that the pressurized gas jets emanating from them impinge on the surface to be cleaned and from this the impurities Drift away representing small particles, and finally through a surface to be cleaned and the nozzle arrangement each drive device moving relative to one another.

W In application of this cleaning device to the cleaning of electrophotographic plates, belts, rollers or the like, which each pass through a large number of treatment stations for the purpose of transferring an image, in each of which one of these stations is applied to the relevant electrophotographic plate or the like the stated object is achieved according to the invention in that said surface to be cleaned is the surface of said electrophotographic plates

* Or the like. Is, so that each of the mentioned DUsenstrahl the paint powder in question is driven away from the surface.

Further features of the invention form the subject of the claims.

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Several embodiments of the invention are shown in the drawings and will be described in more detail below described. Show it:

Fig. 1 is a schematic side view

an electrophotographic apparatus with a cleaning device according to the invention,

FIG. 2 shows a ver with reference to FIG. 1

enlarged, schematic, perspective illustration of the cleaning device according to the invention, whereby individual parts are broken off or shown in section,

3 shows a schematic section longitudinally

the level 3-3 in Fig. 2,

FIG. 4 shows a section similar to FIG. 3

illustration of a further embodiment of the cleaning device according to the invention,

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which an additional cleaning device with a cleaning brush

having,

FIG. 5 shows a section similar to FIG. 4

illustration of yet another embodiment of the invention, in which the additional cleaning device can either be switched on or off,

6 is similar to FIGS. 4 and 5

Sectional view of yet another embodiment of a Cleaning device according to the invention, which also has an additional, optionally actuatable Has cleaning device,

7 shows a schematic representation

a device, which the cleaning apparatus according to the invention in transverse vibrations offset, and

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8 shows a schematic representation

another device which combined the cleaning apparatus according to the invention Lateral and angular vibrations offset.

In principle, the invention can be used wherever small particles are to be removed from surfaces. However the invention will be described below with reference to an electrophotographic apparatus, since cleaning these devices as a result of the electrostatic attraction between Strict requirements are placed on the particles and the surface to be cleaned.

A particular application example of the invention is its application to electrophotographic apparatus the type shown in Fig. 1. This apparatus has a rotatable drum 1, which on its periphery a carries electrophotographic, photoconductive layer 2 on which the respective image is thrown, which is to be copied onto a sheet of paper 3, for example. The photoconductive layer 2 is by means of a corona discharge device 5 evenly on a given

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Potential charged. A document containing the image to be copied is attached in such a way that the image is projected onto the photoconductive layer 2 by a suitable exposure source at an exposure station H. The document moves in a manner known per se at a speed that is synchronous with the speed of the roller 1. The photoconductive layer is discharged at the points where it is illuminated, so that a charge pattern corresponding to the image remains on it.

Then this relevant part of the roller 1 passes a development station 10, at which the electrostatic A dye mixture 11 is applied to the image of the photoconductive layer 2 in a manner known per se. The dye whose charge is opposite to that of the electrostatic image is attracted to the drum surface so that a visible image results.

As the roller 1 continues to rotate counterclockwise, the developed electrostatic image is obtained to a copy paper 3 fed from rollers 14

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the point of contact of the copy paper with the drum is preferably one below this copy paper Corona unit 15 arranged. The corona discharge points has a polarity opposite to the charge of the dye, so that the dye is attracted to the copy paper will. After this so-called corona transfer, the copy paper 3 is again separated from the roller 1 and replaced by a Fixing station passed through, which melts the dye into the copy paper and permanently on it attached. Since not all of the dye making up the image is normally transferred, remains behind After the transfer process on roller 1, there is still a residue of dye 16. With roller 1 rotating further the relevant roller peripheral part arrives at a cleaning device 17 over, which cleans the surface of the photoconductive layer and removes excess dye removed. To help remove excess Dye can be supplied to the cleaning device I7 in a manner known per se, an erasing lamp or an erasing corona discharge device be upstream. This cleaning process ends the cycle of roller 1 in each case Reproduction of the picture in question.

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According to the invention, the cleaning device has a nozzle arrangement 22, which is close to the photoconductive Layer is arranged at a small distance from this. By means of this nozzle arrangement 22 is on the photoconductive Layer of compressed air, which removes the residual dye from the surface of this layer. The pressure of the compressed air flowing out via the nozzles and that when the compressed air streams hit the surface

"Turbulence generated in the photoconductive layer exerted the dye particles exert a substantially transverse force by which the dye particles are removed from the surface the dye layer can be blown away. This leads to improved cleaning and a reduction in the Film formation on the photoconductive ink layer. Since no other cleaning agents apart from air are photoconductive Touching the layer, this type of cleaning also leads to less or no damage to the photoconductive layer at all

fc and thus a longer service life for this layer.

In the illustrated cleaning device according to the invention, the nozzle arrangement 22 has a tube 28,

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in which a plurality of nozzles 24 are formed which direct compressed air entering at one end of the tube 28 onto the photoconductive layer 2. The nozzles 24 can have any suitable configuration and arrangement, however, these nozzles 24 are in the tube 28 in a single one Line formed lying. Each of the nozzles 24 preferably consists of a counterbore formed in the tube 28. at In the illustrated embodiment, a vacuum chamber 50 is provided, which the nozzle arrangement 22 in the essentially completely encloses and comes close to the surface of the photoconductive layer, so that when connecting an outlet 23 of the vacuum chamber with a vacuum source, the air flow resulting from the pressure difference that of the photoconductive layer removes expelled dye particles.

In order to achieve greater turbulence in the air impinging on the photoconductive layer, there is between the individual air jets of the nozzles 24 and the photoconductive layer provided a relative movement. This relative movement results from a device for generating relative transverse movements. Can do this

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any suitable type of linear motion actuator can be used. In the embodiment shown in FIG such a linear motion drive comprises a linear voice coil motor 26 on. The voice coil motor 26 is provided with an annular magnetic path and a winding, which the latter can perform linear movements within the annular magnetic path, so that when excited this arrangement an air bearing in bearing bushes 25

w cylinder 28 is moved back and forth according to the frequency of the excitation voltage. The nozzle arrangement 22 is coupled to the moving winding part of the voice coil motor 26 and is biased towards the center of movement by means of springs 27. When the voice coil motor 26 is excited, the nozzle arrangement 22 is set in reciprocating transverse movements relative to the surface of the photoconductive layer 2, so that greater turbulence is impinging on this photoconductive layer

fc air jets and thus better cleaning of the cleaning device results. In this way, with reference to the embodiment described above, either at lower Air pressure an equally good cleaning can be achieved or it can be achieved by using the same air pressure as a larger one in the embodiment described above Cleaning capacity can be achieved.

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To achieve even better efficiency in removing residual dye from the surface of the photoconductive layer can be the nozzle arrangement 22, in addition to the reciprocating transverse movements described above, also with reference to FIG their axis are set in angular oscillations relative to the photoconductive layer 2. This is longitudinal the surface of the photoconductive layer 2 an even greater air turbulence and thus in terms of cleaning achieved even greater efficiency. The angular vibrations can be generated by any suitable means. In the embodiment of the invention shown in FIG. 8, a further linear voice coil motor is used for this purpose 29 provided, which the nozzle arrangement 22 relative to the photoconductive layer in angular oscillations offset, while this nozzle arrangement 22 with respect to this photoconductive layer 2 at the same time transverse vibrations executes. A movement transmission element 50 with a rounded end portion 52 is attached to the tube 28. With this end part 52 is a fork-shaped end part 48, for example coupled to a shaft, the latter being connected to the voice coil motor 29. Springs 51 urge the tube

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the nozzle arrangement in a rest position in which these nozzles are substantially perpendicular to the photoconductive Layer 2 are aligned. This linear motion drive causes together with the linear motion drive described above a combined transverse and angular movement of the nozzle arrangement 22. By the resulting combined Angular and linear vibrations are applied to the individual air jets relative to the photoconductive layer elliptical or circular orbits.

The cleaning device having air jets according to the invention results in relation to brushes having Cleaning devices have an improved cleaning effect, since cleaning with brushes in addition to the difficulties film formation on the photoconductive layer as well as with regard to the cleaning and replacement of these brushes wear and tear or damage to this layer as a result of its constant contact with the relevant brush brings itself. It has been shown that a combined air jet and brush cleaning also to one longer life of the photoconductive layer leads. The embodiment shown in Fig. 4 as an example

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a cleaning device according to the invention both a photoconductive layer 2 cleaning Air jet arrangement as well as a cleaning device arranged next to it ^ 2 with a rotating brush on. The air jet arrangement includes a nozzle arrangement 22 with a plurality of individual nozzles 24, as essentially described above. The brush cleaning device contains one against each other the movement of the photoconductive layer 2 rotating fiber brush ^ 8, which is arranged so that they with this photoelectric layer 2 is in contact. In this embodiment, the air pressure need not be so to be large as in the above-described embodiment of the invention which purifies only by means of air jets, because an additional cleaning process is carried out by the cleaning device. In the case of the one shown in FIG Embodiment, the air jet arrangement causes the main cleaning / so that the fiber brush 38 is not in each case has to take as much dye with him as with known brush cleaning systems. For this reason, the Brush 38 spin much slower than the brushes of known brush cleaning devices, resulting in less deformation of the fiber ends and thus less frequent replacement of the

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Brush 38. The lower speed of the brush 38 brings with reference to known brush cleaning devices also less local heat generation and less deformation of the photoconductive layer with it, so that both the brush and the photoconductive layer with respect to known systems which only use brushes for cleaning, has a longer lifespan.

In some cases it is sufficient to only periodically clean the brush cleaning device for cleaning the photoconductive ones Layer to be used after a certain period of air jet cleaning. In an example shown in FIG According to the invention, a brush 36 is mounted so that it by means of an appropriate device optionally with the photoconductive layer 2 for the purpose of cleaning the same brought into contact or can be brought away from this into a position of rest. The optionally operable The device of the brush J56 can e.g. Way have a solenoid} 4. This sol ^ 4 is firmly attached to a machine frame, while its anchor on a lever arm of a pivoted lever 40 is attached, the other lever arm on the shaft

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rotatably mounted brush 36 is attached. The solenoid can be excited in each case by a suitable electrical signal "clean roller", which is generated in a corresponding manner. A suitable way of generating this "clean roller" signal is to use a certain number of copy cycles as a basis the working position holding the brush at the photoconductive layer is held to remove particulate matter that has accumulated from that layer, as described in Pig. 5 is indicated by dashed lines.

Another embodiment with optional in operation adjustable cleaning device according to the invention is shown in FIG. This is also just one embodiment illustrative embodiment has according to the invention in the manner described above again an air jet assembly. The cleaning device comes into play in such a way that it removes the photoconductive layer keeps clean for a substantial number of operating cycles at a time. The cleaning device 40 includes an off consist of a fabric or a fabric-like material

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of the cleaning part 42. This cleaning part 42 is accommodated in a housing 44 fastened in such a way that, in the rest position shown in FIG. 6, it is at a certain, short distance from the photoconductive layer. The R <: i _c * imgsteil 42 may be made of woven or nichtgewobenem iasermaterial and this material may be impregnated with this agent a wax, a dry solvent, a liquid solvent, an abrasive or an appropriate combination. In the exemplary embodiment shown in FIG. 6, the cleaning part 42 is impregnated with wax. Periodically when the photoconductive layer is to be cleaned, a "clean roller" signal is generated which energizes the solenoid 46 so that it moves the housing 44 into the working position shown in FIG. 6 with dashed lines, in which the Wax impregnated cleaning part rests on the surface of the photoconductive layer and this both cleans and polishes. The cleaning process is triggered in a suitable manner. A suitable way of triggering the cleaning process is based on counting a specific number of copy cycles, as described above

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has been described. The cleaning part 42 made of fabric renews the surface of the photoconductive layer, by removing the film formed by residual dye from this in each case. In addition, the plaster part grows the surface of the photoconductive layer. The plaster part 42 made of fabric can be in the form of a tape have which in the housing 44 at a relatively slow speed from a tape reel to a tape take-up reel runs while it is in contact with the photoconductive layer, so that during the cleaning process a clean part of the plaster part is in contact with the photoconductive layer.

The speed of the flow out of the nozzle arrangement for the purpose of cleaning the photoconductive layer Air jets depends on the air pressure used, the speed of the photoconductive layer and the size, number and type of individual nozzles, which are formed in the above-mentioned manner, for example in a tube, in such a way that the compressed air jets hit the photoconductive Straighten shift. The nozzles must take into account the distance from the photoconductive

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Layer each have to be arranged close enough to one another so that this photoconductive layer is protected from the air jets is sufficiently covered, otherwise this layer will not be cleaned evenly and will be reflected on the copied Images show stripes. In a particular embodiment of the invention, which is essentially the one shown in FIG corresponds to the embodiment shown, have the individual Nozzles each have a clear width of 0.127 mm, these nozzles are each with a mutual Distance of 0.762 mm from each other and is that tube having these nozzles 0.508 mm from the surface the photoconductive layer located away. In this embodiment of the invention, the air pressure may, for example, be about

1.4 kp / cm, while the surface to be cleaned moves at a speed of about 20 cm / s. With a Embodiment of the invention corresponding to that in FIG. 8 cleaning device shown, in which the pipe having the nozzles both linear and angular vibrations with a frequency of 60 Hz and with an amplitude of 0.762 mm relative to the photoconductive Layer executes, the photoconductive layer was also at much higher speeds or revs still adequately cleaned. From this it can be seen that the arrangement and size of the individual nozzle openings as well

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the pressure applied to the nozzles depends essentially on the speed of the photoconductive to be cleaned Layer as well as the required degree of purity and that on the surface of the photoconductive layer for the gloss required for the copying process in question.

The person skilled in the art will of course have further possible modifications within the scope of the invention and possible applications.

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Claims (12)

Patent claims: y No cleaning device for cleaning with small particles contaminated surfaces, characterized by a pressurized gas supply device, further by a nozzle arrangement (22) connected to the latter and arranged close to the surface to be cleaned (e.g. from 1, 2) with a plurality of individual nozzles (24), the latter being arranged in such a way that the emanating from them Pressurized gas jets impinge on the surface to be cleaned and from this the impurities Drift away representing small particles, and finally through a surface to be cleaned and the nozzle arrangement each drive device moving relative to one another. 2. Use of the cleaning device after ^ Claim 1 on the cleaning of electrophotographic Flatten, belts, rollers or the like., Soft purposes for the transmission of an image in each case a large number of treatment stations run through, being in one of these stations on the relevant electrophotographic Plate or the like. Color powder is applied, characterized in that said surface to be cleaned - 22 - ORlQiNAL INSPECTED 109827/1395 the surface of said electrophotographic plate (1, '2) or the like. Is so that of said Nozzle jets in each case the "relevant color powder part being driven off the surface. 3. Cleaning device according to claim i or 2, characterized by a. Device (25, 26, 27), which the nozzle arrangement (22) with respect to the surface to be cleaned (e.g. from 1, 2) in uninterrupted Transverse vibrations offset, so that from the pressurized gas jets when impinging on the cleaning surface caused turbulence is increased. 4. Cleaning device according to claim 3, characterized by another device (29, 4-8, 52, 50, 51) which the nozzle arrangement (22) with reference to FIG the surface to be cleaned (e.g. from i, 2) in angular oscillations offset so that when the Gas jets on the surface to be cleaned caused turbulence is increased even more. 5. Cleaning device according to one of the claims 1 to 4, characterized by a nozzle arrangement (22) 109827/1395 surrounding negative pressure or vacuum chamber (30) and through Means (23) for producing and maintaining the Negative pressure in this vacuum chamber, such that from the surface to be cleaned (e.g. from 1, 2) the contaminated parts or the said .Farbpulver withdrawn via the vacuum chamber 6. Cleaning device according to one of claims If 1 to 5, characterized in that the nozzle arrangement (22) has a cylinder part or tube part (28), along which the individual nozzles (24), e.g. in the form of Countersunk bores are formed, compressed air preferably serving as the compressed gas. 7. Cleaning device according to claim 6, characterized in that the in the cylinder part or pipe part (28) formed nozzles (24) are arranged in a line. 8. Cleaning device according to claim 7> characterized in that the individual nozzles (24) are each arranged in such a way that they discharge the compressed gas jets in each case essentially at right angles to the surface to be cleaned (e.g. from 1, 2). - 24 - BAD OfflGJNAL 109827/1395 9. Cleaning device according to one of the claims 1 to 8, characterized by a cleaning device (Pig. 4: 32, 38 or, Fig. 5: 34, 40 or Pig. 6:40, 42, 44, 46) with a plaster part (38 or 42) and a plaster part actuation device (34, 40 or 46), which the latter move the cleaning part from a rest position near the surface to be cleaned (e.g. from 1, 2) into one Moved working position in which the plastered part on the surface to be cleaned is applied, and by a cleaning device and the surface to be cleaned in each case relative mutually moving drive device, which latter can be the drive device already mentioned. 10. Cleaning device according to claim 9, characterized characterized in that said cleaning part is a rotating cleaning brush (38). 11. Cleaning device according to claim 9, characterized characterized in that said cleaning part is a pubz part made of fabric or the like, for example in the form of a Band (42). 12. Cleaning device according to claim 11, characterized characterized in that the plaster part (42) made of fabric is impregnated with wax or a wax-like substance. - 25 - 109827/1395 Blank page