US 3851965 A
A rotary cleaning device utilized to remove toner remaining on a rotary photosensitive drum after transfer printing comprises a plurality of resilient members which are assembled into a cylindrical body, a fabric cover encircling the resilient members and having a peripheral length longer than that of the cylindrical body so that portions of the fabric cover are locally folded back on the surface of the cylindrical body, an air suction nozzle and a spacer rod located between the suction port of the nozzle and the cylindrical body such that the folded back portions of the fabric cover are blown away from the periphery of the cylindrical body by the air stream flowing into the air suction nozzle.
Description (OCR text may contain errors)
United States Patent [191 Furuichi et a1.
[ CLEANING APPARATUS FOR ELECTROCOPYING MACHINES  Assignee: Katsuragawa Denki Kabushiki Kaisha, Yaguchi, Ota-ku, Tokyo-to, Japan 22 Filed: May 3, 1973 21 Appl. No.: 357,073
 Foreign Application Priority Data May 8, 1972 Japan 47-053571  US. Cl 355/15, 355/3, 15/1.5,
 Int. Cl G03g 15/00  Field of Search 355/3, l5; 15/1.5, 256.52
3,706,108 12/1972 Taylor ..15/l.5
Primary ExaminerRichard M. Sheer Attorney, Agent, or FirmBosworth, Sessions & McCoy  ABSTRACT A rotary cleaning device utilized to remove toner remaining on a rotary photosensitive drum after transfer printing comprises a plurality of resilient members which are assembled into a cylindrical body, a fabric cover encircling the resilient members and having a peripheral length longer than that of the cylindrical body so that portions of the fabric cover are locally folded back on the surface of the cylindrical body, an air suction nozzle and a spacer rod located between the suction port of the nozzle and the cylindrical body such that the folded back portions of the fabric cover are blown away from the periphery of the cylindrical body by the air stream flowing into the air suction nozzle.
8 Claims, 3 Drawing Figures 1 CLEANING APPARATUS FOR ELECTROCOPYIN MACHINES BACKGROUND OF THE INVENTION This invention relates to an electrocopying machine, and more particularly to an improved cleaning device utilized to clean the surface of a photosensitive drum of the copying machine after a latent image has been formed on the surface of the photosensitive drum, and developed with toner, and the developed powder image has been transfer printed onto a recording mediu such as a sheet of paper. I
Although many types of cleaning device have been proposed to remove toner remaining on the surface of a photosensitive drum,,rotary cleaning brushes comprising fur or other napped soft materials have generally been used. However, the fibers of such a brush tend to become contaminated during use, thereby decreasing the cleaning efficiency of the brush and reducing the quality of the reproduced copies. For this reason, it has been'necessary to manually clean the cleaning brush and the surface of the photosensitive drum. It was believed that such contamination resulted from fusion of the toner to the cleaning brush and to the surface of the photosensitive drum caused by the heat of friction therebetween. Despite attempts to cool the photosensitive drum by blasting thereon cooling air, it was found that the surface of the photosensitive element begins to be contaminated after continuous operation for about 10,000 cycles. As a result of various experiments, it was found that contamination of the surface of the photosensitive element is caused by toner being mechanically adhered to the surface of the photosensitive drum when the ends of the fibers of the cleaning brush beat the surface of the drum and not by the fusion of toner.
In the electrocopying machine of the type outlined above, since an electric field is often used .to transfer the developed powder image onto the recording paper, the paper may be attracted to the surface of the photosensitive drum by to electrostatic force created by the electric field. For this reason, the recording paper is not always removed after transfer printing, thus rendering inoperative the succeeding cycles.
SUMMARY OF THE INVENTION It is an object of this invention to provide an improved electrocopying machine provided with a novel rotary cleaning device which can yieldingly wipe,
rather than beat thesurface of the photosensitive drum,
thereby more effectively cleaning the surface of the drum and increasing the number of cycles of continuous operation without contamination.
Another object of this invention is to provide an improved cleaning device for an electrocopying machine capable of not only removing toner remaining on the surface of the photosensitive drum but also of eff ciently removing a recording paper that was not re-' tosensitive drum, the latent image is developed into a powder image by applying toner upon the latent image, the powder image is transfer printed onto a recording paper and the toner remaining on the image forming surface is removed by a rotary cleaning device, characterized in that the rotary cleaning device comprises a plurality of resilient segments which are assembled into a cylindrical body with a fabric cover encircling the resilient segments. The peripheral length of the fabric cover is longer than that of the cylindrical body so that portions of the fabric cover are locally folded back on the surface of the cylindrical body. An air suction nozzle is oriented generally in the radial direction of the cylindrical body and a spacer rod is located between the suction port of the suction nozzle and the cylindrical body so that, in use, the folded back portions of the fabric cover are blown away from the periphery of the cylindrical body by the air stream flowing into the air suction port. Means areprovided to'urge the rotary cleaning device against the image forming surface of the rotary photosensitive drum.
The present invention is different from the conventional cleaningdevice in the form of a rotary brush, in that the toner isremoved by'the wiping action of the fabric cover yieldably engaging the image forming surfaceof the photosensitive drum so that it is possible to increase the cleaning efficiency. As the folded back portions'of the fabric cover project slightly in the radial direction they act as wipers to wipe and collect the toner. when the folded back portions are blown away from the cylindrical body formed by the resilient members, the spacer rod assists this blowing action and wipes off the toner collected by the folded portions.
BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings: FIG. 1 shows a cross-sectional view of a novel clean- .ing device and a photosensitive drum of an electrocopying machine;
FIG; 2 is an enlarged sectional view showing the operative relation between the cleaning device and its air suction nozzle; and
FIG. 3 is a diagrammatic sectional view showing an DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1 of the accompanying drawings a photosensitive drum or element 1 is rotated in the clockwise direction as shown by an arrow. The drum may-be of any well known construction. An electrostatic latent image is formed on the peripheral sur-' face thereof and developed by using a charged toner, and the developed powder image is transfer printed onto a recording paper. Such method and apparatus are well known in the art and one example thereof will be described later with reference to FIG. 3. At this stage of the description it should be understood that, afterthe powder image has been transfer printed, some of the toner remains on the surface of the photosensitive drum and it is necessary to remove such remaining toner by means of a cleaning device 2. The cleaning de vice '2 comprises rotary cylinder 3 and an air suction nozzle 4 which is connected to an air suction device,
not shown, and oriented generally in the radial direction of the cylinder. The rotary cylinder 3 comprises a I sleeve 6 secured to a shaft 5 and provided with a plurality'of axially extending slits 7. A plurality of flexible members or segments 8, each having a cross-sectional configuration of a sector, are bonded to the outer periphery of sleeve 6 between slits 7.-Cylindrical woven or non-woven fabric panels 9 are clamped between the sleeve 6 and a large diameter portion 5A of shaft 5 with portions of the fabric panels 9 brought to the outside of the cylinder through slits 7 and gaps between adjacent flexible members to completely enclose respective flexible members. The peripheral length of the fabric cover made up of fabric panels 9 is made somewhat longer than that of the cylindrical assembly of the flexible members 8 so that as the cleaning brush 3 is rotated, surplus portions of the fabric cover are folded back on the peripheral surface of the cylinder. Fabric panels 9 may be impregnated with a liquid insulating material such as a silicone oil or liquid paraffin to prober or foamed artificial resin.
The cleaning device 2 is rotated in the same direction as the photosensitive drum las shown in FIG. 1. Any relative speed of these rotary members may be selected but it is advantageous to select a peripheral speed of about 220 .mm/sec. forthe cleaning drum 2 when the rotary photosensitive drum is rotated at a peripheral speed of from 80 to l mm/sec. The cleaning device is normally urged against the surface of the rotary photosensitive drum under a slight pressure so that the contacting portion of the resilient cylinder 3. is slightly deformed as shown in FlG. 1. Although this pressure is not critical, it is advantageous that thev maximum depression of the resilientcylinder be about to 6 mm. Similarly, the number of sector shaped resilient members or segment 8 is not critical. However, this number is chosen such that the fabric panels 9 will not be crimped and such that when a particular resilient mem' her which has been urged against the photosensitive drum is separated therefrom, the deformed portion of that resilient member can readily assume its original expanded form. As described above, since the resilient cylinder is formed by a plurality of resilient members which are fabricated into a cylindrical body and fabric panels 9 encircling the resilient members, as the resilient cylinder is pressed against the rotary photosensitive drum 1 the portion of the resilient member which is in contact with the drum is deformed to increase the contact area therebetween. As contrasted with the conventional rotary cleaning brush in which fibers beat the surface of the photosensitive drum, the fabric cover wipes the surface thereof, thus improving the cleaning these folded back portions act as wipersto wipe and' through air suction nozzle 4. As shown in FIG. 2, a
spacer bar 10 extending in the axial direction of the cleaning drum'2 is disposed between the suction port of the suction nozzle 4 and the resilient cylinder 3. As
the air is sucked into the suction port, the folded back portions of the fabric cover are blown away from the periphery of the resilient cylinder by the stream of air thereby removing the toner from the fabric cover.
More particularly, as shown in FIG. 2 the folded back portion of the fabric cover is blown or bulged outwardly by the stream of air to urge the upper side of the bulged out portion against the spacer bar 10. Accordof operating cycles of the copying machine before the surface of the photosensitive element is contaminated.
' Instead of clamping a seamless cylindrical fabric panel 9 between sleeve 6 and large diameter portion 5A, the sleeve 6 may be made integral with the large diameter portion 5A in which case the fabric panel is divided into a plurality of sections and the opposite ends of each section are secured to the sleeve 'at its slits 7.
FIG. 3 shows an electrocopying machine as a whole including a photosensitive drum or element, a transfer printing device, means for separating recording papers after transfer printing, a cleaning device, and means for conveying recording papers which have not been removed by the separating means but are removed by the cleaning device.
The photosensitive drum 1 may be of any well known construction and latent images may be formed on the image forming surface thereof 'by any well known method. ln the example shown in FIG. 3, the photosensitive element comprises a transparent insulative layer la, a photoconductive layer lb manifesting persistent internal polarization, and an electrode layer 10, these layers being bonded togetherfirito an integral unit mounted on a rotary drum 1a. Where the rotary drum is made of metal, electrode layer 10 may be omitted. A
collect the toner. The powder of the toner collectedin this manner is removed by the air cu'rrent flowing a charge of one polarity is deposited on the surface of the insulative layer by means of a first corona discharge unit 22. Then a charge of the opposite polarity is deposited on the surface of the insulative layer by means of a second corona discharge unit 23. Concurrently therewith, alight image is projected upon the photosensitive element through the corona discharge unit 23 as shown by dot and dash lines, whereby an electrostatic image is formed on the surface of the insulative layer la'corresponding to the light. image. Where the photosensitive layer lb contains deep charge trap levels it is advantageous to project uniform light upon the latent image to intensify the same by providing an electric lamp 24. Reference numeral 25 diagrammatically shows a developer station in which charged toner is applied onto the surface of the insulative layer to develop the latent image as a visible powder image. Then the powder image is transfer printed onto a recording paper 26 while it is urged against the photosensitive element by means of a roller 30. A third corona discharge unit 27 may be used for assisting transfer printing. The recording paper 26 is then removed from the photosensitive drum by a peel off device 28 comprising a rotary perforated drum 28b and a stationary air suction pipe 28a contained in the drum 28b and provided that shown in FIGS. 1 and 2 but is shown somewhat diagrammatically.
During the normal operation of the electrocopying machine, the recording paper 26 which has been transfer printed, with the powder image is removed from the periphery of the photosensitive element by the action of the peel off device 28. Any recording paper that has not beenremoved by the action of the peel off device will be positively removed because at the contacting point the cleaning device 2 which is rotating in the opposite direction to that of the rotary photosensitive drum with no gap between the cleaning drum and the photosensitive drum. The recording paper removed in this manner is conveyed by means of a belt conveyor 14 as shown by dot and dash lines. When the charge on the recording paper is neutralized by a corona discharge unit 15 the recording paper can be more readily removed. The recording paper conveyed by conveyor 14 may be fed to fixing device 29. In the embodiment shown in FIG. 3 although the latent image is formed by utilizing persistent internal polarization and two corona discharge units operating with opposite polarities, it should be understood that the latent image can also be formed bywell known Xerography.
1. Cleaning apparatus for cleaning residual toner from an image forming surface of an electrocopying machine comprising a cylindrical body made up of a plurality of resilient circumferentially adjacent segments, a fabric cover over the outer periphery of said cylindrical body, said fabric cover having aperipheral length longer than that of said cylindrical body, means for securing portions of said fabric cover between said adjacent segments so that portions of said fabric cover are folded back on the surface of said cylindrical body, an air suction nozzle oriented generally in the radial direction of said cylindrical body and having a suction port adjacent thereto, and a spacer rod located between said suction port and said cylindrical body, whereby, in use, said folded back portions of said fabric cover are blown away from the periphery of said cylindrical body and toward said spacer rod by an air stream flowing into said air suction port.
2. Apparatus as claimed in claim 1 wherein said fabric cover is impregnated with liquid electric insulating material.
3. Apparatus as claimed in claim 1 wherein said resilient segments are made of foamed elastic material.
4. Apparatus as claimed in claim 1 wherein said fabric cover comprises a plurality of fabric panels, each panel covering the outer periphery of a corresponding one of said segments, the peripheral length of each of said panels being longer than that of its corresponding segment so that a portion of each fabric panel is locally folded back.
5. Apparatus as claimed in claim 4 including a rotary shaft supporting said cylindrical body, and wherein said body includes a sleeve mounted on said shaft having segments corresponding to said resilient segments spaced radially inwardly thereof, wherein each of said fabric panels surrounds one of said sleeve segments and its corresponding resilient segment and is clamped between said sleeve and said shaft.
6. Apparatus as claimed in claim 1 in combination with a rotatable drum having an image forming surface thereon, means for rotating said drum and said cylindrical body in opposite directions, and, positioned in sequence about said drum in the direction of rotation thereof ahead of said cleaning apparatus, means for forming a latent image on said image forming surface, means for developing said latent image by applying toner thereon, and means for transfer printing said latent image onto a recording paper, and further including means for urging said cylindrical body against the image forming surface of said drum to remove residual toner therefrom after transfer printing of said latent image.
7. A combination as claimed in claim 6 wherein said cylindrical body is also utilized for removing recording paper from the image forming surface on said rotatable drum prior to cleaning, and further including a conveyor between said cylindrical body and said transfer printing means for conveying a recording paper removed by said cylindrical body away from said image forming surface.
8. A combination as claimed in claim 7 including a corona discharge unit disposed between said transfer printing means and said cylindrical body to neutralize the electric charge on said recording paper.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION patent 3,851,965 Dated December 3, 1974 4 Inventor(s)Mas ayoshi Furuichi, Nobuo Algba and'Seiichi Kudo It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as. shown below:
Column- 1, line 28 delete "thereon" after "blasting"; same.
line, insert --thereonafter "air".
Column 1, line 42 delete "to" before "electrostatic".-
Column 1, line 51 insert after "beat" Column 3, line 27 insert --members-- after "resilient".
Column 3, line 44 change "segment" to "segments- Column 3, line 50 begin new paragraph V Iith "As described above" Column 5, line 17 delete "because".
Column 5, line l8 insert --with-- after "point";
' Signed sealed this 11th day of February 1975.
- -(SEAL) Attest: g I
RUTH MASON MARSHALL DANN Attesting Officer of nts and Trademarks FORM 534050 \10-69) I i usccmm-g: 7
" 6 s savanna mnmua emu nu o-an-su Patent No. Dated December 3,
Inventor(s)Masayoshi Furuichi, Nobuo Akiba and Se iichi Kudo It is certified that error appears in the aboveidentified patent and that said Letters Patent are hereby corrected as shown below:
Column 1, line 28 delete "thereon" after "blasting"; same line, insert -thereon-- after "air".
Column 1, lineb42 delete "to" before "electrostatic".-
Column 1, line 51 insert--, after "beat".
Column 3, line 27 insert -membersafter "resilient".
Column 3, line-44 change "segment" to segment's--.
Column 3, line 5O begin new paragraph with "As described above" Column 5, line 17 delete "because".
Column 5, line 18 insert --with-- after "po in tF'r Signed sealed this 11th day of February 1975.
' (SEAL) Attest: I v RUTH c MASON A H LL DA1N t t Attesting Officer ommlssloner' 0 a en s and Trademarks ORM 73-1050 \10-69) I v uscoMM-oc 6C375-P9 U i GOVIIIIIII HHITIIG OFFICE 11., O-lill