Patent Publication Number: US-3879124-A

Title: Apparatus for removing remnants of powder images in electrophotographic copying machines

Description:
United States Patent 1 Eppe et al.  
 [451 Apr. 22, 1975 APPARATUS FOR REMOVING REMNANTS OF POWDER IMAGES IN ELECTROPHOTOGRAPHHC COPYKNG MACHINES [76] Inventors: Rudolf Eppe, Sudstr. 5, 8021 Taufl irchen; Georg Fryda, Ganghoferstr. 52, 8 Munich 2; Ludwig Miillritter, Gogrdelerstr 20, 8025 Unterhaching; Giinther Schnall, Garchinger Str. 20, 8052 Eching; Hans-Joachim Sclnreclte, Strehlanger ll, 8 Munich 83; Josef Pfeifer, Ter-Meer-Str. 10, 8025 Unterhaching; Giintlier Abb, Meginhardstr. 30, 8031 Gilching, all of Germany [22] Filed: Dec. 5, 1973 [21] Appl. No.: 397,652  
 [30] Foreign Application Priority Data Sept. 16. 1972 Germany 2245575 [52] US. Cl 355/15; l5/256.52 [51] Int. Cl G03g 15/00 [58] Field of Search l5/l.5, 256.5, 256.51,  
 [56] References Cited UNITED STATES PATENTS 3.099.856 8/1963 Eichorn et al. 355/15 X Primary E.\&#39;aminerFred L. Braun Atlorney, Agent, or Firm-Michael S. Striker [5 7] ABSTRACT An electrophotographic copying machine wherein the surplus toner which remains on the photoconductive layer of the copying cylinder subsequent to transfer of powder images onto a carrier is removed by rotary brush having radially extending bristles consisting of artificial fur or the like. The bristles are deformed on contact with the photoconductive layer and propel particles of toner against a travelling toner-retaining band which is collected by a rotary takeup reel and is guided by a wall of an expendable plastic casing for the brush and takeup reel in such a way that an unsupported stretch thereof extends from a point close to the photoconductive layer to a projection of the wall which maintains the band in contact with and causes the band to deform the bristles. The casing carries a supply reel for the band and is installed in a receptacle extending radially of the copying cylinder. The open end of the receptacle can be closed by a lid which thereby causes two clutches to engage the shafts of the brush and takeup reel with the output shafts of two discrete motors.  
 25 Claims, 2 Drawing Figures APPARATUS FOR REMOVING REMNANTS OF POWDER IMAGES IN ELECTROPI&#39;IOTOGRAPHIC COPYING MACHINES BACKGROUND OF THE INVENTION The present invention relates to electrophotographic copying machines wherein powder images containing particles of toner are formed on a photoconductive layer and are transferred onto a carrier while the layer travels along an endless path.  
  It is already known to clean the photoconductive layer upon removal of a powder image in order to remove the remaining particles of toner before the layer receives a fresh powder image. In heretobefore known copying machines, the cleaning apparatus for removing remnants of toner comprises a rotary brush having a core which is surrounded by a coating of felt or by discrete bristles consisting of animal hairs or of hairs made from a suitable synthetic plastic material. Certain cleaning apparatus use brushes whose bristles consist of mink or rabbit hairs. In many presently known copying machines, the brush is permanently installed adjacent to the path of movement of the photoconductive layer and the cleaning apparatus further comprises a vacuum cleaner which removes toner particles from the bristles and prevents the thus removed toner particles from contaminating the machine. A drawback of such cleaning apparatus is that the provision of a vacuum cleaner contributes excessively to their initial and maintenance cost.  
  It is further known to replace the vacuum cleaner with a web or band of toner-collecting material which is biased against the bristles of the rotating brush by a suitable roller and serves to collect the particles of toner which are propelled by the bristles after the bristles are free to reassume their undeformed positions as well as to remove toner particles from the brush proper. Such toner-collecting bands contribute to the lower cost of the cleaning apparatus; however, the presently known bands (mainly due to the manner in which they are mounted in the copying machine) are incapable of collecting sufficient quantities of toner and/or of properly cleaning the rotating brush so that the copying machine is contaminated after short periods of use and the accumulation of toner in the brush proper is excessive.  
  Attempts to use electrostatic cleaning apparatus have met with little success, mainly for the reasons outlined in connection with cleaning apparatus which employ vacuum cleaners.  
 SUMMARY OF THE INVENTION An object of the invention is to provide an electrophotographic copying machine with a novel and improved apparatus which is capable of collecting large quantities of surplus toner without resorting to vacuum cleaners and/or electrostatic cleaning devices.  
  Another object of the invention is to provide novel and improved means for collecting toner particles which are removed from the photoconductive layer by one or more rotary brushes.  
  A further object of the invention is to provide a cleaning apparatus which is sufficiently inexpensive to warrant the manufacture of the majority of its parts as an expendable assembly which can be discarded after a prolonged period of use.  
  An additional object of the invention is to provide a novel and improved mounting for the toner-collecting band or web in an apparatus for collecting surplus toner in an electrophotographic copying machine.  
  Still another object of the invention is to provide a cleaning apparatus wherein the rotary parts are automatically disengaged from one or more prime movers when the user decides to gain access to the cleaning apparatus.  
  A further object of the invention is to provide a cleaning apparatus which can be installed in existing copying machines with minimal and inexpensive alterations of such machines.  
  Another object of the invention is to provide a cleaning apparatus whose toner-collecting capacity is surprisingly high in spite of the fact that the tonercollecting parts are preferably of the expendable type and that the apparatus does not employ electrostatic and/or vacuum-operated toner collecting devices.  
  The invention is embodied in an electrophotographic copying machine which comprises a photoconductive layer movable in a predetermined direction (the layer may be a cylinder which rotates about its axis) and along an endless path to thereby receive tonercontaining powder images in a first portion and to be relieved of powder images in a second portion of the path whereby at least some toner particles normally adhere or are likely to adhere to the layer in a third portion of the path along which successive portions of the layer travel on their way from the second toward the first path portion. In accordance with a feature of the invention, the copying machine further comprises a cleaning apparatus which serves to remove toner from the photoconductive layer in the third portion of the endless path and comprises a substantially cylindrical brush having a rotary core and flexible toner-removing bristles which surround the core and contact successive increments of the layer whereby the bristles undergo a certain amount of deformation in response to movement into contact with the layer and reassume their undeformed positions relative to the core in response to termination of contact with the layer, a source (e.g., a supply reel) of bank-like toner-collecting material, rotary takeup means for drawing the band-like material from the source, and guide means for the band-like material. The guide means may constitute a wall member which forms part of an expendable casing or magazine for the brush and takeup means and which comprises a projecting portion (e.g., a rib which is parallel to the axis of the brush) for urging the band-like material against the bristles downstream of the locus where the bristles move away from contact with the layer and a second portion (e.g., a suitably rounded deflector) which is closely adjacent to the layer. The band-like material travels from the second portion toward the projecting portion of the guide means so that a stretch of the band-like material between the two portions of the guide means remains unsupported and serves to intercept toner particles which leave the brush as a result of termination of deformation of the bristles and/or under the action of gravity and/or centrifugal force.  
  The projecting portion of the guide means preferably causes the band-like material to penetrate into the brush and to deform the bristles to thereby further enhance the separation of toner particles from the brush before the bristles return into contact with the photoconductive layer.  
 , vantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing. I  
 I BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary sectional view of an electrophotographic copying machine which embodies the improved cleaning apparatus; and  
  FIG. 2 is a sectional view as seen in the direction of arrows from the line 11-11 of FIG. 1.  
 DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1, there is shown a portion of an electrophotographic copying machine which comprises a housing 1 including two mutually inclined walls v 2, 3 which form part of a channel or receptacle fora magazine or casing 12. The receptacle or channel including the walls 2, 3 has an open inner end which is adjacent to the periphery of a rotary copying cylinder 4 having a cylindrical layer 5 of photoconductive material. The outer end of the receptacle or channel including the walls 2, 3 is also open but can be closed by a cover member or lid which is pivotally secured to the housing 1 by a hinge 6. That portion of the lid 7 which is remote from the hinge 6 is provided with a projection 7a which can be engaged by a retaining lever pivotally mounted in the housing 1, as at 45, and being biased against a stop 46 by a relatively weak helical spring 47. The lid 7 is closed to assume the position which is shown in FIG. l when the copying machine is in use and can be forcibly pivoted to an open position (whereby the projection 7a is automatically disengaged from the lever) when the operator wishes to gain access to the cleaning apparatus or when the operator wishes to remove a used cleaning apparatus prior to in sertion of a fresh cleaning apparatus into&#39;the channel.  
  .When the copying machine is in use, the copying cylinder 4 is driven to rotate in the direction indicated by an arrow A whereby the layer 5 travels along an endless path in a first portion of which it receives a powder image, in a second portion of. which it is relieved of the powder image, and a third portion of which is adjacent to the inner &#39;endof the channel including the walls 2 ,and3.  
  The exact construction of all devices at the stations which are adjacent to the&#39;path of the layer 5 forms no part of the invention. FIG. 1 merely shows a charging The present invention provides a novel and improved apparatus whichcan be employed to remove from the layer 5 remnants of toner before the cleaned portions of the layer 5 return into register with theopening in the light conducting shaft 11. Were the particles of toner permitted to adhere to the layer 5, they could&#39;influence the quality of the next powder image and/or contaminate the copying machine.  
 The cleaning or toner removing apparatus comprises the aforementioned magazine or casing 12 which is preferably mass-produced of a suitable synthetic plastic material so that it can be discarded after a certain period of use, together with all such components of the cleaning apparatus which are mounted therein and/or path of the layer 5. The station where the particles of toner are sprinkled onto the layer 5 to form thereon a thereon. The casing l2tapers in a direction toward the inner end of the receptacle or channel including the walls 2, 3 so that it can be automatically arrested at or close to an optimum distance from the layer 5 on the copying cylinder 4. The side walls 12f, 123 (see HO. 2)  
 of the casing 12 are provided with aligned openings for two stub shafts 13a, 13b at the respective axial ends of a cylindrical core 13 forming part ofa substantially cylindrical brush further having a sleevebody consisting of bristles or hairs 14. For example, the core 13 may have a diameter of 30 millimeters and each bristle [4 may have a length of ll millimeters. The bristles 14 may consist of flexible synthetic plastic material such I as is used for the making of artificial furs and are glued I mined optimum speed, for. example, at 600-800 RPM.  
 The distance between the axis of the core 13&#39; and the axis of the copying cylinder 4 is preferably such that the minimum distance between the peripheral surface of the core 13 and the layer 5 is slightly less than the length of a bristle 14, e.g., 9-10 millimeters.  
  -When the cylinder 4 is driven counterclockwise and the brush l3, 14 also rotates counterclockwise, successive bristles 14 contact the layer 5 at the locus M and move out of contact with the layer 5 at the locus N.  
 Thus, the bristles are deformed at M and are permitted to reassume their normal positions relative to the core 13 as soon as they move beyond the locus N.  
  The side walls 12f, 12g of the casing 12 are further provided with aligned openings for stub shafts 15a, 15b at the respective axial ends of a second core 15 which forms part of or constitutes a simple takeup reel for band-like, toner-collecting material 16 (hereinafter called the band for short). The source of band 16 is a supply reel having a&#39;core 18 provided with stub shafts 18a, 18b which extend with at least some friction into complementary openings or slots provided therefor in bearing brackets 17 which are integral with and are located externally of the casing 12. As shown in FIG. 1, the bearing brackets 17 extend toward the lid 7. The surfaces 17A bounding the openings or slots in the bearing brackets 17 can be said to constitute a rudimentary braking means which insures that the supply reel including the core 18 offers a certain resistance to rotation when the takeup reel (core 15) is rotated counterclockwise, as viewed in FIG. &#39;1, in order to collect the band 16. However, it is equally possible to provide the bearing brackets 17 with suitable friction pads which bear against one or both stub shafts 18a, 18b and/or against the core 18 to thereby offer a certain resistance to clockwise rotation of the supply reel. When the core of the takeup reel is rotated in a direction to collect the band 16, the latter advances in the direction indicated by an arrow C. The guide means for that portion of the band 16 which extends between the supply and takeup reels includes a section or wall member 12a of the casing 12. The wall member 12a has an external surface 12A which faces away from the brush 13, 14 and an internal surface 128 which faces the adjacent bristles 14. During travel from the core 18 toward the core 15, successive increments of the band 16 travel along the external surface 12A and thereupon along the internal surface 128.  
  The wall member 120 has an end portion or deflector 12b which is closely adjacent to and defines with the layer 5 a narrow gap G through which the band 16 passes on its way toward the core 15 of the takeup reel. The width of the gap G is preferably constant, i.e., the portion 12b of the wall member 12a is preferably parallel to the axis of the cylinder 4 and hence also to the axis of the core 13. The wall member 12a further comprises a substantially triangular projecting portion 12c which extends from the surface 12B and deforms the adjacent bristles 14. That stretch (16a) of the band 16 which extends between the portion 12b and the projecting portion 12c is unsupported because the wall member 120 is provided with a depression or recess 12d. The band 16 contacts the bristles 14 in a region ahead of the projecting portion 12c, as considered in the direction of rotation of the brush 13, 14. The width of the gap G between the portion 12b of the wall member 12a and the layer 5 on the copying cylinder 4 need not substantially exceed 1 millimeter and is preferably between 0.5-1 millimeter. The core 15 of the takeup reel is driven by a second prime mover (e.g., an electric motor 39 shown in FIG. 2) at such a speed that the lengthwisemovement of band 16 in the direction indicated by the arrow C is very slow, e.g., l millimeter per copy. The projecting portion 120 can penetrate into the annulus of bristles 14 to a depth of 2-3 millimeters, i.e., the distance between the tip of the projecting portion 12c and the periphery of the core 13 is preferably 8-9 millimeters. The stretch 16a of the band 16 is under tension due to the provision of aforementioned braking means on the bearing brackets 17 for the core 18 of the supply reel.  
  A further wall member or portion 12e of the casing 12 defines with the layer 5 a second gap GG which is adjacent to the locus MM. The left-hand end portion of the wall member 122 is connected with an elastic sealing element or lip 19 which contacts the layer 5 and the bristles 14 in the region of the locus M. The angle between the left-hand surface of the lip 19 and the adjacent portion of the layer 5 is a relatively small acute angle. For example, the lip 19 may be made ofa strip of polyester foil having a thickness of 0.25 millimeter. The width of the lip 19 (as considered in the circumferential direction of the layer 5) is preferably such that the free lower edge of the lip contacts the bristles 14 at or immediately adjacent to the locus M. This prevents the accumulation of toner particles in the region of the lower edge of the lip 19 because the bristles 14 sweep the toner away toward and beyond the locus N so that the toner particles impinge on the stretch 16a of the band 16. The main purpose of the lip 19 is to prevent escape of toner particles from the casing 12 along the wall member 12e; such particles could contaminate the corona discharge device including the electrode 9.  
  The copying machine is provided with two clutches which can be engaged to respectively connect the output shafts 42, 43 of the motors 38, 39 with the cores 13, 15. Furthermore, the copying machine comprises means (including the lip 7) for engaging or disengaging the two clutches. The arrangement is preferably such that, when the casing 12 is properly inserted into the channel or receptacle including the walls, 2, 3, a movement of the lid 7 to closed position automatically entails an engagement of the two clutches so that the motor 38 can drive the core 13 and the motor 39 can drive the core 15, and that a movement of the lid 7 to open position automatically results in disengagement of the two clutches so that the casing 12 can be withdrawn through that (outer) open end of the channel which is normally closed by lid 7. The actuating means for the two clutches comprises a first rod 22 which is articulately connected to the lid 7, as at 22a and is further articulately connected to a lever 23 in the housing 1. The lever 23 is coupled with a similar lever 25 by means of a second rod 24 (see also FIG. 2). The levers 23, 25 are respectively connected to and can turn two sleeves 27, 26 which are respectively rotatable on fixed cylindrical bearing elements 41, 40. The sleeves 26, 27 are respectively provided with suitable inclined (substantially helical) cam faces 26a, 27a which can cooperate with complementary cam faces 28a, 29a of two sleeves 28, 29 in the housing 1. The sleeves 28, 29 are movable axially of the respective bearing elements 40, 41 and are rigidly connected to each other by a web or rib 30 which is biased upwardly, as viewed in FIG. 2, by a helical spring 31 so that the cam faces 28a, 29a respectively bear against the cam faces 26a, 27a.  
  The bearing elements 40, 41 respectively receive axially movable clutch elements in the form of bolts 32, 33 which are respectively aligned with the stub shafts 13a, 15a of the cores 13, 15. The bolt 32 has an enlarged portion or head 32a which is outwardly adjacent to the bearing element 40 and sleeve 28, and the bolt 33 has a similar head 33a which is outwardly adjacent to the bearing element 41 and and sleeve 29. The inner end portions of the bolts 32, 33 are rounded and can enter suitable (preferably conical) sockets or recesses 13c, in the stub shafts 13a, 150 when the bolts 32, 33 are caused or allowed to move toward the cores 13, 15. The bolts 32, 33 are respectively biased toward the cores 13, 15 by helical springs 34 and 35 which react against the housing 1 and respectively bear against collars 32b, 33b.  
  The stub shafts 13b, 15b are respectively provided with recesses or sockets 13d, 15d for conical centering projections 36, 37 of the output shafts 42, 43. The centering projections 36, 37 cooperate with the rounded inner end portions of the bolts 32, 33 to respectively maintain the cores 13, 15 in exact parallelism with each other and with the axis of the cylinder 4 when the lid 7 is closed. The conical centering projections 36, 37 preferably consist or carry coats of friction generating material so that they can rotate the cores 13, 15 by friction when the motors 38, 39 are on.  
  When the lid 7 is moved to the closed position of FIG. 1, the rods 22, 24 turn the sleeves 27, 26 by way tions indicated by arrow D so that the rounded inner end portions of the bolts 32, 33 respectively penetrate into the sockets 13c, 15c and cause the sockets 13d. 15d to receive the conical centering projections 36, 37.  
 v. The cleaning apparatus is then ready for use and begins to accumulate toner&#39;particles as soon asthe motors 38, 39 are started. It will be noted that the closing of the .lid 7&#39; not only results in establishment of a driving&#39;connection between the output shafts 42, 43 andthe cores 13, 15 but that such closing also resultsin automatic centering of the cores 13, 15 with respect to the bolts 32, 33 and projections 36, 37 and hence in a movement of the brush and takeup reel to optimum positions with respect to the layer on the copying cylinder 4.  
  The inclination of the cam faces 26a, 27a, 28a, 29a is selected in such a way that the heads 32a, 33a move away from the, sleeves 28, 29 when the rounded inner end portions of the bolts 32, 33 extend into the sockets 130, 150. Thus, the bolts 32, 33 are then free to per- I form limited axial movements. This is desirable to insure that the cores 13, are properly centered in spite of eventual deviations of the dimensions of sockets 13c, 13d, 15c, 15d from optimum dimensions and in spite of eventual substantial clearances with which the stub which are removed from the layer 5 by the bristles 14 are propelled against the stretch 16a of the band 16 between the portions 12b and 12c of the wall member l2a. The material of the band 16 is such that it retains the toner particles and transportsthe intercepted particlestoward the core 15 of the takeup reel. This insures that the particles of toner cannot enter the copying machine proper where they could contaminate the parts at various stations surrounding the copying cylinder 4. Thus, the contamination of copying machine is avoided in spite of the fact that the cleaning apparatus does not employ a vacuum cleaner or an electrostatic toner collecting device. Moreover, the bristles l4 cooperate with the band 16 to insure a thorough and reliable cleaning of the layer 5 because the particles of&#39;toner which reach the stretch 16a adhere to the band and are transported away from the layer 5. Still further, the band 16 prevent a premature saturation of the brush with particles of toner, not only because the particles whichare propelled by the bristles 14 from the locus N toward the stretch 16a adhere to the band 16 but also because the stretch 16a contacts the bristles 14 immediately upstream of the projecting portion 120 which results in removal of substantial quantities of toner particle sfrom&#39; the bristles 14. Since the stretch 16a travels v.jna di rection away from the gap G, the band 16 effectively prevents even minor accumulations of toner particles in the region of this gap when the copying machine is in use. Accumulations of toner in the region of the gap G are highly undesirable because such toner could be entrained by the layer 5 beyond the cleaning 16a, i.e., which continue to adhere to the bristles 14 while the bristles move-from the locus N toward the projecting portion 120, are separated from the bristles 14 during&#39;contact with the band 16 upstream of the portion 120. The stretch 16a is in a highly satisfactory wiping contact with the bristles which also contributes to more reliable transfer of toner particles onto the stretch 16a before this stretch advances beyond theregion of direct contact with the bristles. The deformation of the bristles l4 in response to direct contact with they are permitted to abruptly straighten out and to propel remaining particles of toner toward the portion 16b of the band 16, i.e., against the band portion between the projecting portion 12c and the takeup reel. Extended experiments with our cleaning apparatus indicate that the removal of toner particles from the bristles 14 in the regions between the locus N and the roll of convoluted band 16 on the core 15 of the takeup reel is just as satisfactory as when the band is cleaned by a vacuum generating device or by an electrostatic device. Thus, a thorough cleaning of those bristles 14 which return into contact with the layer 5 can be achieved at a cost which is but&#39;a small fraction of the cost of cleaning apparatus employing vacuumcleaners and/or electrostatic toner removing devices. The provision of a relatively simple projecting portion 12c in place of conven tional rollers or drums also contributesto the simplicity and lower cost of the improved cleaning apparatus. The  
 station to interfere with the formation of satisfactory radius of curvature of the tip of the projecting portion 12c is preferably very small (smaller than the radius of the smallest roller which is used in&#39;place of the projecting portion in conventional cleaning apparatus); this insures an abrupt deformation and an abrupt straightening of bristles 14 which travel toward, past and beyond the projecting portion 120. Such abrupt deformation and straightening enhance the transfer of toner particles from the bristles 14 onto the stretch 16a and band portion 16b.  
  The&#39;recess or depression 12d in the surface 128 of the wall member 12a preferably extends all the way from the portion 12b to the portion 1200f the wall member 120. This enables the stretch 16a to flex and to overlie a substantial portion of the brush 13, 14 (FIG. 1 shows that the stretch 16a contacts the bristles 14 along an arc of approximately 45). 7  
 The thorough and reliable cleaning action of the band 16 renders it possible to transport the band at a.  
 very low speed without risking excessive accumulations of toner particles inthe brush 13, 14, i.e., between the bristles l4, and without risking the possibility of transfer of toner particles from the band 16 onto the brush. The particles which would be removed from the&#39;band 16 by the bristles 14 would be transferred onto the layer 5 in the region of the locus M. The possibility to transport the band 16 at an extremely low speed (as mentioned above, the toner can be transported through a distance of one millemeter per print) renders it possible to construct the casing 12 and the parts mounted therein and/or thereon as an expendable assembly which can be discarded after a relatively long period of use. The open side of the casing 12 (such open side faces the layer on the copying cylinder 4) is completely closed by the lip l9,bristles l4 and band 16 so that the particles of toner cannot escape from the casing 12 even if the latter is practically filled with toner. i.e., even when the major part of the band 16 is already convoluted on the core 15 of the takeup reel. When the supply of clean band 16 on the core 18 is exhausted, the lid 7 is moved to its open position to thereby automatically disengage the motors 38, 39 from the cores l3, l5, and the operator simply withdraws the casing 12 with the empty core 18 from the receptacle including the walls 2, 3 prior to inserting a new casing with a full supply of fresh band 16 on the core 18. The lid 7 is thereupon returned to its closed position and the copying machine is ready for use.  
  The lip 19 is inclined and dimensioned in such a way that it properly engages the layer 5 and the bristles 14 of the respective brush even if the dimensions of one casing 12 deviate substantially from the dimensions of the next-following or preceding casing. This is attributed to the fact that the lip 19 makes an acute angle with the adjacent portion of the layer 5 and also that the width of the lip suffices to invariably insure the establishment of contact with the bristles 14 in the region of the locus M where the bristles undergo deformation in response to movement into contact with the layer 5.  
  The entire casing 12 preferably consists of a suitable synthetic plastic material which is sufficiently inexpensive to justify its disposal together with the cores 13, 15 and 18. The major parts of the two clutches, the motors 38, 39 and the means for actuating the clutches are mounted in the housing 1 so that they can be used again and again even if the dimensions of successively inserted casings deviate substantially from each other.  
  Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of our contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalents of the claims.  
  What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:  
  1. ln an electrophotographic copying machine, a combination comprising a photoconductive layer m0vable in a predetermined direction along an endless path to thereby receive toner-containing powder images in a first portion of said path and to be relieved of powder images in a second portion of said path whereby at least some toner particles normally adhere to said layer in a third portion of said path along which said layer advances toward said first portion; and apparatus for removing toner from said layer in said third portion of said path, comprising a substantially cylindrical brush including a rotary core and flexible toner-removing bristles surrounding said core and arranged to contact successive increments of said layer whereby said bristles undergo deformation in response to movement into contact with said layer and reassume their undeformed positions relative to said core in response to termination of contact with said layer, a source of band-like toner-collecting material, rotary takeup means for drawing said band-like material from said source, and guide means having a projecting portion for urging said band-like material against said bristles downstream of the locus where said bristles move away from contact with said layer and a second portion adjacent to said layer, said band-like material being arranged to travel from said second portion of said guide means toward said projecting portion of said guide means so that a stretch thereof between said portions of said guide means intercepts toner particles which leave said brush as a result of termination of deformation of said bristles and/or under the action of centrifugal force.  
  2. A combination as defined in claim 1, wherein said source comprises a rotary supply reel for band-like material and said projecting portion of said guide means is spaced apart from said locus and extends into the path of movement of said bristles so that the bristles are flexed by the band-like material in the region of said projecting portion.  
  3. A combination as defined in claim 1, wherein said guide means comprises a wall member having a first surface facing away from said brush and a second surface facing said brush, said band-like material being arranged to travel from said source toward said second portion of said guide means along said first surface and to travel from said second portion of said guide means toward said projecting portion of said guide means along said second surface of said wall member.  
  4. A combination as defined in claim 1, wherein a portion of said stretch contacts said bristles in a region located ahead of said projecting portion, as considered in the direction of movement of said band-like material from said second portion of said guide means toward said projecting portion of said guide means.  
  5. A combination as defined in claim 1, wherein said band-like material is spaced apart from said guide means between said second portion of said guide means and said projecting portion of said guide means so that said stretch of said band-like material is unsupported.  
  6. A combination as defined in claim 5, wherein said guide means has a recess extending between said second portion of said guide means and said projecting portion thereof to provide room for the flexing of said stretch by the bristles of said brush.  
  7. A combination as defined in claim 1 wherein said second portion of said guide means defines with said layer a narrow gap of substantially constant width through which said band-like material advances from said source toward said projecting portion.  
  8. A combination as defined in claim 7, wherein said second portion of said guide means constitutes a deflector which changes the direction of movement of said band-like material through an obtuse angle.  
  9. A combination as defined in claim 7, wherein said layer is a cylindrical layer and the axis of said brush is parallel to the axis of said layer, said second portion of said guide means being elongated and parallel to the axis of said layer.  
  10. A combination as defined in claim 1, wherein said apparatus further comprises a casing including said guide means and having an open end adjacent to said layer in the region of said third portion of said path.  
  11. A combination as defined in claim 10, wherein said brush and said takeup means are rotatably mounted in said casing and said casing comprises external bearing means for said source.  
 7 said path.  
  12. &#39;A combination as defined in claim 11, wherein said source comprises a rotary supply j reel for said band-like material and said bearing means comprises means for braking said supply reel while said takeup means rotates to collect said band-like material so that the band-like material is tensioned between said supply reel and said takeup means.  
 13. A combination as defined in claim 10, wherein said casing includes a portion adjacent to said layer and located in the region of the locus where said bristles move into contact with said layer, and further&#39;compris- I ing elastic sealing means provided on said portion of &#39;said casing and engagingsaid layer.  
  114. A combination as defined in claim 13, wherein said sealing means comprises a flexible lip making an acute angle with the adjacent portion of said layer.  
 . 15. A combination as defined in&#39;claim l3, wherein said sealing means contacts said bristles.  
 16. A combination as defined in claim 10, wherein said casing is expendable and consists of synthetic thermoplastic material. i  
  17. A combination as defined in claim 16, wherein said casing comprises integral bearing means-for said source. j  
  18. A combination as defined in claim 10, wherein said brush and, said takeup means are rotatably mounted in said casing and further comprising a receptacle for-said casing, said casing being movable in said receptacle toward and away&#39;from said third portion of l9.A combination as defined in claim 18, wherein said layer is a cylindrical layer andsaid receptacle extends substantiallyradially .of said layer.  
 20. A combination as defined in claim 1, further comprising wall means for supporting said brush and 12 said takeup means and means for centering said brush and said takeup means in said wall means.  
 21. A combination as defined in claim 1, wherein said core of said brush comprises first shaft means and said takeup means comprises second shaft means, and further comprising drive means for said shaft means and clutch means actuable to connect said shaft means with said drive means.  
  22. A combination as defined in claim 21, further comprising a receptacle for said brush and said takeup means, said receptacle having an open end and further comprising means for actuating said clutch means including cover means for the open end of said receptacle. said cover means being movable between open and closed positions to thereby respectively disengage and engage said clutch means.  
  23. A combination as defined in claim 22, wherein said clutch means comprises reciprocable first and sec- 0nd clutch elements which are respectively coaxial ment relative to said motion transmitting means.  
 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. .3,879,l24  
 DATED Apr. 22, 1975 INVI&#39;NtORth) ;Rudolf Eppe, Georg Fryda, Ludwig M&#39;illritter, Gunther Schrtall,  
 Pans-Joachim Schrecke, Josef Pfeifer and Gunther Abbe It is certlfted that error appears III the above-Identified patent and that smtt Letters Patent arr: hereby corrected as shown below;  
 In the heading on the cover sheet insert the name and address of the assignee as follows:  
 - Agfa-Gevaert Aktiengesellschaft, Leverkusen, Germany Signed and Scaled this A ties I:  
 RUTH C. MASON C. MARSHALL DANN (&#39;mnmm&#39;inncr uj&#39; Iurcn/s um/ &#39;lrutlcmurkx .4 Hosting ()jft&#39;cer UNITED STATES PATENT OFFICE CERTE&#39;FICAIE 0F CORRECTION PATEN&#39;I NO. 13,879,124  
 DATED Apr. 22, 1975 mvr&#39;NroRrs) .Rudolf Eppe, Georg Fryda, Ludwig Ml illritter, Gx&#39;inther Schnall,  
  Hans-Joachim Schrecke, Josef Pfeifer and Gr inther Abbe H 15 C(Zfllflfld that error appears III the nb0ve--1dent|flr:d patent and that smrl Letters Patent arr: hereby correcleri as shown below:  
 In the heading on the cover sheet insert the name and address of the assignee as follows:  
  Agfa-Gevaert Aktiengesellschaft, Leverkusen, Germany gigned and gealcd this RUTH C. MASON .4 resting ()fj&#39;rver C. MARSHALL DANN (&#39;11I)1rr1r.s.rimrcr nj&#39;lulcnls uml &#39;l&#39;rurlvmurkr