Patent Publication Number: US-3879123-A

Title: Copy machine

Description:
United States Patent Fisher Apr. 22, 1975 [5 COPY MACHINE 3.684.368 8/1972 Tanno 35513 x 3.697.160 10/1972 Clark 355/3 [75] lnventor: William G. Fisher, Umon City. Ga. 1713.736 1/1973 Sargis I n 355,3 X [73] Assignee: B. J. Powell, Atlanta. Ga. 3.732.003 5/1973 Altmann 355/16 X 3.734.608 5/1973 Hlckey ct al 355/16 X [22] Filed: Jan. 26, 1973 3.754.822 8/1973 Melrose 355/8 3,765,757 10/1973 Weigl 355/16 X [21] APPL 3271126 3.770.345 11/1973 Kawakubo 81:31 355/15 x 3.795.025 3/1974 Sadamitsu 355/15 X [52] U.S. Cl. 355/14; 355/3 R; 355/3 DD;  
  355/8&#39;, 355/11&#39;, 355/15; 355/16; 355 7 Pnmary Examiner-Richard M. Sheer 51 int. Cl 003; 15/00 8 Firm-B Powell [58] Field of Search 355/3, 10, 11. 12, 14.  
 355/15. 16, 17. s ABSTRACT A copy machine for making copies on plain bond [56] References Cited paper which includes a photoconductive master on UNlTED STATES PATENTS which a blanket electrostatic charge is first imposed 2.889.758 6/1959 13611611 355/8 y F master w a latent 2 001.374 8/l959 GundlOCh 355/16 x clectwsmtc mage master 023,731 M962 schwammmw H image on the original document. The latent electro- 3.062.110 11 1962 Shcpardson 61111,, static image is then developed and the developed 3.146.688 9/1964 Clark ct a1. 355/1 1 image transferred to a sheet of copy paper. The trans- 3.25l.706 5/1966 Walkup 355/3 DD fen-ed image is then fused onto the copy paper to pro- 3-515J23 Bhilgal 355/14 duce a finished copy and any residual toner left on the 3.619.050 11/1971 Swanke 355/16 master is cleaned therefrom to prepare the master for 3.646.866 3/1972 Baltazz1 t al. 355/16 X further cop in 3.647.294 3/1972 Egnaczak 355115 y 3.667.840 6/1972 Engel ct a1 355/15 X 8 Claims, 17 Drawing Figures P TENTEE&#39; APRZZ m5 SHIU 1 BF 9 ATENTEBAPR22 ms snmamfe MENTED Z 3.879.123  
 saw u If 9 PLTENIEBA RZZMB 3.879.123  
 sumsnrs C Tl-A COPY MACHINE BACKGROUND OF THE INVENTION Copying machines using non-photoconductive copy paper are available on the market today. Such machines are generally referred to as employing a xerographic process. Such machines have generally been so expensive to build that their use has been limited to high volume applications. Moreover, because such machines have been extremely complicated, an extensive amount of maintenance has been required to maintain such machines operational.  
 SUMMARY OF THE INVENTION These and other problems and disadvantages associated with the prior art are overcome by the invention disclosed herein by providing a machine which is simple in construction and therefore inexpensive to produce and maintain. Moreover, a transfer mechanism is provided which effectively transfers the developed image from the photoconductive master to the copy paper over a greater tolerance range in the plane of the master.  
  The apparatus of the invention includes generally a photoconductive master, a conveyor for moving the master along a prescribed endless path, a developer section for selectively applying toner to the master as it moves thereby, a cleaning section for selectively cleaning the master as it moves thereby, a charging section for selectively applying an electrostatic charge to the master, an exposure section for exposing a document to the master, feed means for feeding copy paper onto the master, transfer means for transferring the image on the master to the copy paper, a control circuit for controlling the operation of the machine, and a fuser section for fusing the transferred image on the copy paper.  
  These and other features and advantages of the invention will become more clearly understood upon consideration of the following specification and accompanying drawings wherein like characters of reference designate corresponding parts throughout the several views and in which: i  
 BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of the machine embodying the invention;  
  FIG. 2 is a side elevational view of the machine with the side cover removed;  
  FIG. 3 is a view similar to FIG. 2 shown partly in cross-section to show the arrangement of the various components;  
  FIG. 4 is an enlarged cross-sectional view of the ground connection of the master;  
  FIG. 5 is a top plan view of the master conveyor system;  
  FIG. 6 is an enlarged partial cross-sectional view of the developing section;  
 FIG. 7 is an enlarged view of the cleaning section;  
 FIG. 8 is a top plan view of the transfer section;  
  FIG. 9 is a cross-sectional view of the cleaning section;  
  FIG. 10 is a side view of one of the cycle timing mechanism;  
 FIG. 11 is a side view of the other cycle timer mechanism;  
  FIG. 12A-12D is an electrical schematic of the control circuit;  
  FIG. 13 is an end view of the cycle timer shown in FIG. 10; and,  
  FIG. 14 is an enlarged view of the primary timer switch.  
  These figures and the following detailed description disclose specific embodiments of the invention, however, it is to be understood that the inventive concept is not limited thereto since it may be embodied in other forms.  
 DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS Referring to the drawings. it will be seen that the machine 10 includes generally a master 11, a master conveyor 12, an exposure section 14, a supply of copy paper 15, a paper feed section 16, a cutter mechanism 18, a developing section 19, a cleaning section 20, an image transfer mechanism 21, a charging mechanism 22, a fusing section 24, a paper discharge section 25 and a main drive 28, all mounted in a housing 26. In order to make a copy of an original document A seen in FIG. 1, it is placed in the exposure section and the controls manipulated to actuate the printing cycle. First, the master 11 is charged with a blanket electro static charge through the charging mechanism 22 and then the master is exposed with the exposure section 14 to form a corresponding latent electrostatic image on the master corresponding to the visual image on the original document. The master conveyor 12 moves the master 11 past the developing section 19 where the latent electrostatic image is developed. The conveyor 12 continues to move the master 1! with the developed image thereon and as it passes under the paper feed section 16, a sheet of copy paper from the supply of copy paper 15 is fed onto the master 11 in registration with and juxtaposition over the developed image on the master and cut to length by the cutter mechanism 18. With the copy paper overlying the image on master 11, it is moved with master 11 under the transfer mechanism 21 where the developed image is transferred onto the copy paper. As the paper and master 11 are moved by the conveyor 12, the copy paper is discharged into the discharge section 25 which moves the copy paper through the fusing section 24 to fuse the transferred image onto the copy paper and then moves the thusly finished copy out of the machine. In the meantime, the conveyor 12 moves the master 11 past the cleaning section 20 where any residual developed image is removed from the master and the master 11 moved back to its exposure position whereupon the conveyor 12 stops the master.  
 MASTER AND MASTER CONVEYOR Referring now to FIGS. 2 and 3, it will be seen that the master conveyor 12 includes an endless carrier belt 30 mounted on support rollers 31 rotatably journalled in the frame 32 of housing 26. The belt 30 may have toothed timing strips 34 along opposite edges of the belt which engage appropriately toothed pulleys on opposite ends of each of the rollers 31 to insure timing of belt 30. The rollers 31 are driven by main drive 28. The master 11 is mounted on the belt 30 and movable therewith. The master 11 is of known construction with a photoconductive insulating top layer 35 which overlies a conductive foil layer 36 which in turn overlies an insulating layer 38 as best seen in FIG. 4. The leading and trailing edges of master 11 are provided with U- shaped binders 39 which are used to attach the master to belt 30. It will be noted that binders 39 are connected to the conductive foil layer 38 as will become more apparent. The layer 35 may be made of any photoconductive insulating material such as selenium or the sulfide compounds.  
  The leading edge of master 11 is connected to belt 30 through a Z-shaped clamp 40 which is fixed to belt 30. The clamp 40 is conductive so that the conductive foil layer 36 can be connected to electrical ground when grounded contacts 41 seen in FIG. 4 engage the clamp 40. As soon as the belt 30 moves the clamp 40 out of engagement with contacts 41, the conductive foil layer 36 is disconnected from ground as will become more apparent. The trailing edge of master 11 is attached to belt 30 through a resilient member 42 attached to belt 30 at one end and releasably connected to the trailing end of master 11 at its other. The member 42 serves to maintain tension in master 11 so that it lays flat on belt 30 and can pass around the rollers 31 without stretchmg.  
  The belt 30 is driven as will be explained so that master 11 moves clockwise along a prescribed endless path P seen in FIG. 3 defined by belt 30. A registration hole 44 is provided in belt 30 as seen in FIG. 3 to insure registration as will be explained.  
 EX POSURE SECTION The exposure section 14 serves to expose the visual image on the original document A to the master 11 to form a latent electrostatic image on the master corresponding to the image on the original document. Section 14 includes an exposure glass 50 with a selectively closable cover 51 as seen in FIG. 3. The original document A is placed between cover 51 and glass 50 so that the visual image faces glass 50.  
  A travelling lens and light unit 52 is movably mounted on a pair of spaced apart parallel carriage rods 54 carried by machine frame 32 so that unit 52 moves under glass 50 parallel thereto and parallel to the upper flight P,-U of the path P along which master 11 is moved. A reversible lens motor M drives the unit 52 back and forth along rods 54 through a drive cable 55 as seen in FIG. 3. The lens and light unit 52 includes an exposure lamp 56 which causes the visual image on document A to be transmitted via mirrors 58 and lens 59 along light path P out of unit 52 and onto master 11 to expose same as unit 52 moves along the rods 54 as is known in the art. It will be noted that lens 59 is a reversing lens so that the latent electrostatic image formed on master 1] is a mirror image of the visual image on document A as will be more fully explained. A blinder shade 60 is provided which is connected to unit 52 to prevent excess light from being transmitted to master 11 to expose same as is well known in the art.  
 PAPER FEED SECTION The paper feed section 16 shown is well known in the art and is capable of selectively feeding copy paper in roll form or sheet form. The supply of copy paper illustrated in FIG. 3 is in roll form in which a single web 61 is fed from a roll 62 and cut to length with cutter mechanism 18. Section 16 includes a pair of primary feed rolls 70 which constantly rotate in contact when the machine is operating. a pair of roll paper secondary feed rolls 71 which are selectively rotated in contact during operation of the machine to feed the web 61 to primary feed rolls 70, and a pair of sheet paper secondary feed rolls 72 which are selectively rotated in contact during operation of the machine to feed sheets of copy paper to the primary feed rolls 70. Appropriate guides 74 are provided for directing the copy paper from rolls 71 to rolls and from rolls 72 to rolls 70.  
  The cutter mechanism 18 is located between the roll paper secondary feed rolls 71 and the primary feed rolls 70 as seen in FIG. 3 to selectively cut web 61 into sheets as will become apparent. Mechanism 18 is a conventional rotary cutter with a stationary knife 76 and rotary knife 78.  
 DEVELOPING SECTION The developing section 19 serves to develop the latent electrostatic image on master 11 into a visible image as the master 11 passes point P on path P, at which the section 19 is located by applying toner particles of known configuration and characteristics to the master which adhere to the charged area of the master. Such toners are commercially available. Section 19 in cludes a developer brush 80 which is rotatably mounted in a toner receptacle 81 best seen in FIG. 6. The brush 80 is rotated clockwise as seen in FIG. 6 by a motor M4 shown schematically in FIG. 12. The brush 80 includes a support tube 82 rotatably journalled on shaft 84 with relatively stiff short bristles 85 around the periphery thereof anad along the length thereof. Relatively flexible magnetically responsive long bristles 86 are also provided around the periphery of tube 82 and along the length thereof. A permanent magnet 88 is carried on shaft 84 to cause the Ion g bristles 86 to stand up or lie down. The rotational position of magnet 88 can be varied while the tube 82 rotates therearound independently thereof. The magnet 88 is positioned so that its magnetic pole which makes bristles 86 stand up, here shown as the North pole, is at point P directly opposite master 11 as it passes thereby as seen in FIG. 6. Thus, it will be seen that bristles 86 stand up as point P is passed but lie down as the opposite pole of magnet 88 is passed. The section 19 is adjusted so that the tips of bristles 86 just contact the exposed surface of master 11 as it is moved past point P The receptacle 81 is filled with toner T as seen in FIG. 6 and a granular developer is dispersed therein so that the toner will be carried thereon as is known in the art. The short bristles 85 pick up the toner covered developer particles as brush 80 rotates with the amount retained on brush 80 being controlled through adjustable doctor blade 89 mounted on receptacle 81. As the tube 82 rotates past the stand up pole of magnet 88, the long bristles 86 stand up to move the toner coated developer particles into contact with the charged surface of master 1] so that the toner particles are electrostatically transferred to the master to develop the latent electrostatic image. The developer particles, being unattracted to master 11 continue with brush 80 and are redeposited into receptacle 81 for recoating with toner T.  
 CLEANING SECTION The cleaning section 20 serves to selectively remove any residual toner T from master 11 after the developed image on the master has been transferred to the copy paper as will become apparent. Section 20 is positioned at point P, adjacent the path P, of master 11 as seen in FIG. 3. As best seen in FIGS. 7 and 9, section includes a duct support which movably mounts a cleaning brush 101 adjacent path P, at point P Brush 101 is rotatably journalled in one end of a pair of support arms 102 pivoted to the support 100 at their opposite ends. As the arms 102 are pivoted clockwise as seen in FIG. 7, the brush 101 comes into contact with master 11 to clean same as it moves past point P The brush 101 is covered in rabbit hair and is commercially available. Brush 101 is rotated in a counterclockwise direction as seen in FIG. 3 or a clockwise direction as seen in FIG. 7 by a motor M7 through a belt and pulley arrangement 104 seen in FIG. 7.  
  The arms 102 are provided with outwardly directed camming flanges 105 which are engaged by a pair of interconnected camming links 106 pivoted by a solenoid SOL-6. Thus, when it is desirable to clean the master 11, solenoid SOL-6 is actuated to move brush 101 into contact with master 11 at point P as seen in FIG. 9. When solenoid SOL-6 is deactuated, the brush 101 is retracted as shown in FIG. 7 out of contact with master 11. A pair of beaters 108 are provided to keep brush 101 clean.  
  Duct support 100 provides a vacuum passage 109 from brush 101 to a removable plenum chamber 110 so that the removed toner will be withdrawn therethrough. A disposable filter 111 is provided in chamber 110 which entraps the toner as it is withdrawn into the chamber. Vacuum is provided to withdraw the air and toner into chamber 110 by a vacuum fan unit 112 driven by motor M8. Appropriate openings 114 are provided in the front and back of chamber 110 to allow the air to pass therethrough.  
  The cleaning section 20 also includes a cleaning lamp 115 positioned upstream of the brush 80 to help discharge any residual charge on the master 11 prior to cleaning.  
 CHARGING AND TRANSFER MECHANISMS The charging mechanism 22 includes a corona mounted on and movable with the light and lens unit 52 to selectively impose a blanket electrostatic charge on master 11 prior to exposure. The corona 120 is powered through bus 121 and sliding contact 122 seen in FIG. 2. The corona 120 is mounted so as to move just above the surface of master 11 to be charged and charges the master during movement of the light and lens unit 52 to the right as seen in FIG. 2.  
  The transfer mechanism 21 includes a conductive roll 124 rotatably mounted between pivot arms 125 as best seen in FIGS. 3 and 8. Arms 125 are pivoted on the machine frame 32 and springs 126 constantly urge roll 124 down onto belt 30. As the copy paper is fed onto master 11, it passes under roll 124 so that roll 124 contacts the copy paper and forces it toward master 11 in registration with the developed image. At the same time, an electrostatic charge is imposed on the copy paper to cause the developed image to be transferred from the master to the copy paper as will become apparent.  
 PAPER DISCHARGE AND FUSER SECTIONS The paper discharge section 25 receives the copy paper with the developed image thereon from the right end of the upper flight of path P, as seen in FIG. 3, transports it through the fusing section 24 and out of the machine. Section 25 includes a plurality of upper endless spring belts 130 carried by pulleys 131 and a plurality of lower endless spring belts 132 carried by pulleys 134. The pulleys 131 and 134 are driven from main drive 28 so as to drive the copy paper out of the machine.  
  The fuser section 24 includes an upper heater ele ment H, mounted between the upper and lower flights of upper spring belts 130 and a like lower heater element H mounted between the upper and lower flights of the lower spring belts 132 in opposition to element 11,. As the copy paper with the developed image thereon passes between elements H, and H the image is fused onto the copy paper in known manner.  
 MAIN DRIVE The main drive 28 controls the movement of the master 11 and copy paper through the machine. Main drive 28 includes an endless drive chain partly seen in FIGS. 2 and 3 which is driven by main drive motor Ml shown schematically in FIG. 12 so as to drive the chain 140 in the direction shown by arrow 141 in FIG. 3. The main drive chain 140 drives the primary feed rolls 70 of the paper feed section 16 and the pulleys 131 and 134 of the paper discharge section 25 directly, selectively drives the roll paper secondary feed rolls 71 though clutch CL1 shown schematically in FIG. 12, selectively drives sheet paper secondary feed rolls 72 through clutch CL-2 shown schematically in FIG. 12, selectively drives the rollers 31 of of the master conveyor 12 through clutch CL-4 shown schematically in FIG. 12, and selectively drives the primary circuit timer CT1 shown in FIGS. 10 and 13 through clutch CL-3 shown schematically in FIG. 12. Clutches CL-l through CL-4 are of the electromagnetic type of well known construction that transmit power when energized but do not when de-energized.  
 CONTROL CIRCUIT A control circuit 200 of the machine is shown schematically in FIG. 12 and includes generally a primary power section 201, a charge and transfer section 202 and a control section 204. The machine is turned on by closing power switch SW1 to supply power to the various sections 201, 202 and 204. First, the machine goes through a pre-heat cycle in order for heating elements H, and H to reach fusing temperature and then the machine is ready to print a copy.  
  Closing power switch SW1 supplies power to section 201 through hot wires 205, 206 and 208 and common ground wire 209. Hot wire 205 is selectively connected to the motor power portion 210 of section 201 through time delay relay TDR-l of known construction with a variable time delay activated by external normally open switch contact LL, of lamp and load relay LL closing and times out to transfer the normally closed internal contact TDR-l, to its closed position. While contact LL is closed, internal contact TDR-l, is closed as well as while the relay TDR-l is timing out to connect hot wire 201 to secondary hot wire 211 through normally open contacts PH-l of preheat relay PH. When contact LL, opens, contact LL, closes. The relay TDR-l is set to time out after a prescribed lapse of time upon closing of contact LL, to allow the print cycle to complete. Main drive motor M1, fan motor M2 which cools lamp 56 in unit 52, and vacuum fan motor M8 are all connected between hot wire 211 and ground wire 209 to operate as long as contact TDR-l and contacts PH-l are closed.  
  Two cycle timers CT1 and CT2 are illustrated in FIGS. 10, 11 and 13. Cycle timer CT1 is the primary cycle timer and is driven by chain 140 through clutch CL-3 shown in FIGS. and 13. Timer CTl includes an actuator CTl, which activates the paper cutter mechanism through switch SW Switch SW is movable about the path of actuator CTl to vary the cut length of the copy paper through drive 220 of known construction. Timer CT] has three adjustable cams CTl-A. CTl-B and CTl-C which respectively operate master conveyor switch SW developer switch SW and paper feed switch SW as will become apparent.  
  Cycle timer CT2 is driven by timer motor M6 as seen in FIG. 11 which is energized by the leading edge of the copy paper closing normally open timer switch SW3 at primary feed rolls 70 seen in FIG. 3. Timer CT2 has four adjustable cams CT2-1, CT2-2, CT2-3 and CT2-4 which respectively operate image transfer switch SW cleaning switch SW holding switch SW, and end-ofcycle switch SW as will become more apparent.  
  Developer motor M4 is connected between wires 211 and 209 through switch SW The cleaning brush motor M7 is connected between wires 211 and 209 through contacts SW -l of switch SW Lens drive motor MS is connected between wires 211 and 209 in the right movement of unit 52 through normally open contact PRT-l of print relay PRT in series with normally closed contacts SW-R of the right limit switch SW-R and in the left movement of unit 52 through normally closed contact PRT-2 of relay PRT in series with normally open contact STP-l of stop relay STP.  
  The hot wire 206 supplies power to the lamp and charge power portion 225 of the primary power section 201. The exposure lamp control circuit 226 is selectively powered from wires 206 and 209 through nor mally open contact LL of relay LL while the heater power circuit 228 is selectively powered from wires 206 and 209 through normally closed contact LL of relay LL. The lamp circuit 226 is activated by normally open contacts LL of relay LL to power lamp 56 through an R-C network. diac D, and triac T,. The heater circuit 228 is activated by normally closed contacts TEMP of temperature control relay TEMP to power heating elements H and H through an R-C network and triac T When the correct fusing temperature is reached, contacts TEMP open to energize ready light L Hot wire 208 supplies power to the miscellaneous power portion 229 of power section 201. Portion 229 includes timer motor M of cycle timer CT2 connected between wires 208 and 209 through timer switch SW-3 and timer holding switch SW is parallel. Cleaning lamp 115 is connected between wires 208 and 209 and is powered while power switch SW-l is closed. A solid state temperature controller TC is also connected between wires 208 and 209 for power. Controller TC is of known construction with variable temperature set control TC that causes controller TC to produce an output to energize coil TEMP of temperature control relay TEMP in response to sensor TC, detecting a prescribed temperature at heating elements H, and H as is well known.  
  Wires 208 and 209 are connected respectively to common hot wire 240 and common ground wire 241 of charge and transfer control section 202 through step down transformer T-l. The high voltage power supply HV is connected between wires 240 and 241 through normally open contacts PRT-3 of relay PRT in series with safety switch SW. closed when the housing 26 is closed. Normally open transfer switch SW, in series with variable resistance R. is connected in parallel across contacts PRT-3. Resistance R allows the power output of power supply HV to be varied during image transfer as is apparent. The power supply HV is of known construction which produces a high voltage d-c power output at O in the order of 5000 volts. The output 0 is connected directly to corona and to the transfer roll through a voltage divider network 242.  
  Wires 240 and 241 are connected to common hot wire 250 and common ground wire 251 of control section 204 through rectifier R to supply d-c voltage to wires 250 and 251. The coil PH of preheat relay PH is connected between wires 250 and 251 through normally open contacts TEMP of relay TEMP in parallel with holding contacts PH-2 of preheat relay PH.  
  The master conveyor clutch CL-4 is connected between wires 250 and 251 through belt time delay relay TDR-2 in series with normally open contacts SW-L of left limit switch SW-L and belt switch SW-7. The normally closed contacts SW-L are connected in parallel across contacts SW-L and switch SW7. The normally closed internal contacts TDR-2 are connected to the clutch CL-4 while the normally closed external timing contact SW,,-] and normally open external timing contact SW -Z control the variably adjustable time delay of the relay. Belt switch SW-7 is actuated by the registration hole 44 in belt 30 as seen in FIG. 3 so as to close switch SW-7.  
  Roll paper feed clutch CL-l is connected between wires 250 and 251 in series with normally open paper feed switch SW and contacts SW-6 of paper feed selector switch SW-6. Sheet paper feed clutch L-2 is connected between wires 250 and 251 through contacts SW-6 of selector switch SW-6 in series with paper feed switch SW Light L and L indicate what type of copy paper is being fed.  
  The coil PRT of print relay PRT and coil LL of load relay LL in parallel are connected between wires 250 and 251 through momentary pushbutton print switch PB-l in series with normally closed contacts STP-2 of stop relay STP. Holding contacts PRT-4 are connected in parallel across print switch PB-l. End-of-cycle switch SW of cycle timer CT2 in series with multiple copy switch SW-S is also connected in parallel across print switch PB-l. Multiple copy switch SW-S is a mechanical countdown switch of known construction which is closed on multiple copies and counts down the copies until the required number have been made whereupon it opens.  
  The cycle timer clutch CL-3 is connected between wires 250 and 251 through timer start switch SW-2 seen in FIG. 14. When clutch CL-3 is momentarily energized, the cycle timer CTl is released to cycle for one cycle of machine operation as is known in the art.  
  The coil STP of stop relay STP is connected between wires 250 and 251 through normally open contacts SW-R of right limit switch SW-R. When relay STP is energized, the print circuit is disabled. The cutter solenoid SOL-5 is connected between wires 250 and 251 through normally open cutter switch SW so that rotary knife 78 is rotated to cut web 61. The cleaning brush solenoid SOL-6 is connected between wires 250 and 251 through normally open contacts SW,,,-2 of switch SW,, on cycle timer CT2.  
  Referring now to FIG. 14, it will be seen that switch SW-2 is a one way switch. The actuator 260 of switch SW-Z is driven by a drive link 261 pivoted thereto. An abuttment 262 on actuator 260 limits clockwise rotation of link 261 to the position shown by solid lines in FIG. 14 while the link 261 is free to pivot counterclockwise as shown by dashed lines. A spring 264 constantly urges link 261 clockwise against abuttment 262 so that the drive lug 265 on lamp and lens unit 52 engages the drive roller 266 on link 261 as it moves to the right and left as seen in FIG. 3. As the unit 52 moves to the right, the lug 26S drives the link 261 counterclockwise against spring 264 so that switch SW-2 is not closed, but as unit 52 moves to the left, lug 265 drives link 261 clockwise against abuttment 262 to close switch SW-Z momentarily.  
  Because the right. limit switch SW-R is only closed momentarily by the light and lens unit 52, a timing circuit 270 is provided as seen in FIG. 12D to maintain the relay STP energized for a sufficient time to allow the unit 52 to return to its left initial position. Circuit 270 includes a timing relay TIM with its coil TIM, connected between wires 250 and 251 in series with a time delay network TDN of known construction and normally open contacts STP-3 of relay STP. When switch contacts SW-R close and energize relay STP, contacts STP-3 close to activate the network TDN and relay TIM. Once activated, network TDN maintains relay TIM energized for a prescribed period of time which maintains contacts TIM-l in parallel across switch contacts SW-R, closed to keep relay STP energized. When network TDN times out, contacts TIM-1 open to deenergize relay STP and stop motor M5 and unit 52.  
 OPERATION In operation, it will be seen that the supply of copy paper is loaded into the machine and fed to the roll paper feed rolls 71. Power supplied to the machine from 120 volt A-C power source. The power switch SW-l is then closed to supply power to the machine. This supplies power to the heater elements H, and H through the normally closed contacts LL, of the lamp and loader relay LL and the normally closed contacts TEMP-1 of the temperature control relay TEMP. As soon as the heating elements H, and H, have reached temperature, the sensor TC causes the temperature controller TC to energize the temperature control relay TEMP. This causes the contacts TEMP-1 to open and illuminate the ready light L, to indicate that the machine is ready to make copies. At the same time, the contacts TEMP-2 are closed to energize the preheat relay PH to cause the normally open contacts PH-l and PH-Z to close. The closing of contacts PI-I-l supplies current to the motor power portion of the primary power section 201 and the closing of contacts PH-2 holds the preheat relay PH in an energized condition until the main power switch SW-l is opened.  
  The original document A is then placed on the exposure glass 50 with the visual image side down and the cover 5] closed. The number of copies are selected with the multiple copy switch SW-S and the print switch PB-l depressed to initiate the print cycle. When switch PB-l is momentarily closed this energizes relays PRT and LL through normally closed contacts STP-2 and are held energized by the contacts PRT-4 which close when relay PRT is energized. This holds the relays PRT and LL in an energized condition until contacts STP-2 are opened. Energizing relay LL serves to close contacts LL, so that time delay relay TDR-l closes the internal contacts TDR-l, to supply power to the motors of the machine. This causes the main drive motor M1 to rotate to drive the main drive chain 140 thereby driving the primary feed rolls and the discharge section 25. This also energizes the fan motor M2 and the vacuum fan motor M8 to supply cooling air to the lamp 56 of the light and lens unit 52 and to cause air to be drawn through plenum chamber in the cleaning section 20. Also, the lens drive motor M5 is energized when the relay PRT is energized through contact PRT-1 and the normally closed contacts SW-R, of the right limit switch SW-R to cause the lens and light unit 52 to be moved to the right as seen in FIGS. 2 and 3 of the drawings. At the same time, the lamp 56 is illuminated through the now closed contacts LL,, and LL, because the load and lamp relay LL is energized. Also at the same time, the high voltage power supply HV is energized by contacts PRT-3 being closed when relay PRT is energized. This supplies power to the corona to cause the master 11 to have a blanket electrostatic charge imposed thereon as the light and lens unit 52 moves to the right followed almost immediately thereafter by the master 11 being exposed from the lamp 56 to selectively discharge certain portions of photoconductive layer 35 to form the latent electrostatic image corresponding to the visual image on the original document A on the master 11. As has already been noted, the latent electrostatic image is a mirror image of that on the original document A since this image will be correctly oriented when it is transferred to the copy paper.  
  The light and lens unit 52 continues to be moved to the right by the lens drive motor M5 until the right limit switch SW-R is contacted to open normally closed contacts SW-R, and close normally open contacts SW- R,. This energizes relay STP to cause contacts STP-2 to de-energize relays PRT and LL. This opens contact LL, and closes contact LL, so that the time delay relay TDR-l enters its timing cycle. At the same time, the contacts PRT-2 and contacts STP-1 are closed to reverse the lens motor M5 and drive the light and lens unit 52 to the left as seen in FIGS. 2 and 3. This also opens contacts LL, and LL,, so that the lamp 56 is depowered. Also, the high voltage power supply HV is de energized by the contacts PRT-3 opening.  
  As the light and lens unit 52 moves to the left as seen in FIGS. 2 and 3, it momentarily closes the timer start switch SW-2 to momentarily energize the cycle timer clutch CL-3 and allow the cycle timer CTl to cycle one time. As cycle timer CTl rotates cams CTl-A, CTl-B and CTl-C, cam CTl-A first closes switch contacts SWll-l to cause the normally closed internal contacts TOR-2, of the time delay relay TDR-2 to open to deenergize clutch CL-4 and allow the belt 30 to be driven from the master drive chain 140. This moves the master 1! with the latent electrostatic image thereon toward the point P,, at the developing section 19. As the master l1 approaches point P,,, the cam C&#39;Il-B closes the developer switch SW to energize the developer motor M4 and supply toner T to the master 1] as it moves thereby to develop the latent electrostatic image. It will be noted that cam CTl-B maintains switch SW closed for a sufficiently long period of time for the developing section 19 to completely develop the latent electrostatic image on the master 11. After the master H has moved part point P cam CTl-B opens switch SW to de-energize the developer motor M4.  
  Cam CTl-A continues to maintain switch SW,, closed to allow the drive chain 140 to continue to move the belt 30. As the master ll approaches the point at which the paper feed section 16 furnishes the sheet of copy paper to the master l1, cam CTl-D closes paper feed switch SW to energize the appropriate paper feed clutch CL-l or CL-Z to supply paper to the primary feed roll 70. If the roll of copy paper is being used, the actuator CT], closes the cutter switch SW at the appropriate time to energize the cutter solenoid SOL-5 and cause the paper to be cut to the desired length. The feeding of the copy paper is times so that the cut sheet of copy paper is fed onto the master 11 as it passes under the image transfer roll 124 so that the copy paper is in registration over the developed image on the master 11 in the same relationship that the visual image on the original document had to the original document. As the leading edge of the cut sheet of copy paper moves into engagement with the primary feed rolls 70, it actuates the cycle timer switch SW-3 to energize the cycle timer motor M6 for cycle timer CT2. This drives the cams of the cycle timer CTZ which in term causes the cam CT2-3 to close switch SW and maintain the cycle timer CT2 in operation until it has cycled whereupon the cam CT2-4 opens switch SW to stop motor M6. As the cycle timer CT2 rotates, the transfer switch SW, is closed appropriately by the cam CTZ-l to energize the high voltage power supply HV to supply power in the neighborhood of 1,250 volts to the transfer roll 124 as the sheet of copy paper and master simultaneously move under the roll 124. This causes the developed image on the master 11 to be transferred onto the copy paper thereover. it will also be noted that because the roll 124 is constantly urged downwardly on the master ll, good contact between the master l1 and the copy paper is insured and excellent transfer is accomplished. After the copy paper and master 1] have passed under the roll 124, the switch SW is opened to de-energize the high voltage power supply HV. It will also be noted that relay TDR-2 has gone through its time delay because contacts SW,,-l have been closed so that contacts TDR-Z, have reclosed after hole 44 has passed switch SW-7 so that it remains open to allow conveyor 12 to continue to move master ll around the path P, for the second time.  
  As the master 11 is continued to be moved by the conveyor 12, the copy paper with the transferred image thereon is discharged from the right hand end of the upper flight P,-U into the discharge section 25 and between the upper flight of the lower belt 134 and under the lower flight of the upper belt 130 so that the sheet of copy paper is moved between the heating elements H, and H Because the heating elements H, and H are at fusing temperature, the developed image on the sheet of copy paper is fused thereon so that it becomes a permanent visual image and then the section 25 deposits the finished copy in the copy tray.  
  in the meantime, the belt 30 is continuing to move the master 11 around the path P, for the second time and the cam CTD-Z closes switch SW just prior to the time the master 11 reaches the cleaning section at point P, on path P,. This closes contacts SW,,,-l to energize the cleaning brush motor M7 while at the same time closes the contacts SW, -,-2 to energize the cleaning brush solenoid SOL-6. Thus, the brush is raised into contact with the master l1 and rotated so as to remove any of the residual toner from the master 1] to prepare the master 11 for the next print cycle. The removed toner flows through the duct 109 into the plenum chamber 110 where it is caught in the filter 111. Periodically, the plenum chamber 110 is removed and the filter 111 replaced. The belt 30 continues to move the master 11 around to its initial position on the upper flight P,-U of the path P, whereupon hole 44 engages switch SW-7 to again energize the drive clutch CL-4 to disengage the rollers 31 from the main drive chain and stop the master 1] in registration for the next printing cycle. If the multiple copy switch SW-S is still closed, the closing of end-of-cycle switch SW, by cam CT2-4 at the end of the cycle of timer CT2 again initiates the printing operation and will continue to do so until the multiple copy switch SW-S is open at the end of a printing cycle.  
  While specific embodiments of the invention have been disclosed herein, it is understood that full use may be made of modifications, substitutions and equivalents without departing from the scene of the invention.  
 I claim:  
  I. [n a copy machine for reproducing a visual image from an original document onto copy paper, the improvement comprising:  
 a photoconductive insulating master:  
 conveyor means for selectively moving said master along a first prescribed endless path from an initial position;  
 charging means for selectively imposing an electrostatic charge on said master; exposure means for selectively exposing said charged master with the visual image from the original document to form a corresponding latent electrostatic image on said master; said exposure means including a support track fixed relative to said endless path adjacent said initial position, a lens and light assembly movably mounted on said support track for movement over said master in said initial position in a first direction and a second direction, and lens drive means for selectively moving said lens and light assembly along said support track in said first and second directions, said charging means mounted on said lens and light assembly for movement therewith; developing means adjacent said first path at a first position, said developing means having a first operative condition for developing the latent electrostatic image on said master as said conveyor moves said master past said first position, and a second inoperative condition for not developing the latent electrostatic image on said master as said conveyor moves said master past said first position;  
 cleaning means adjacent said first path at a second position, said cleaning means having a first operative position for cleaning said master as said conveyor means moves said master past said second position, and a second inoperative position for not cleaning said master as said conveyor means moves said master past said second position;  
 feed means for selectively moving said copy paper into juxtaposition with and registration over the developed image on said master;  
 transfer means for transferring said developed image from said master to said copy paper in juxtaposition with said developed image; and  
 control means operatively connected to said conveyor means, said developing means, said cleaning means, said charging means, said exposure means, said feed means and said transfer means for causing said conveyor means to hold said master stationary in said initial position while causing said charging means to impose a blanket electrostatic charge on said master during movement of said lens and light assembly and said charging means in said first direction followed by causing said lens and light assembly to expose said master to the visual image on the original document to produce a latent electrostatic image on said master corresponding to said visual image during movement of said lens and light assembly in said second direction, for thereafter causing said conveyor means to move said master along said prescribed path past said first position and for selectively activating said developing means as said master moves thereby to cause said developing means to assume said first operative condition and develop said latent image, for thereafter causing said feed means to feed said copy paper onto said master in registration with said developed image as said master continues to move along said path, for causing said transfer means to transfer said developed image from said master to said copy paper as said master continues to move, for selectively causing said cleaning means to assume said first operative position as said master is moved past said second position to selectively clean any remaining image from said master after copy paper with the transferred image is removed from said master and as said master continues to move, and for causing said conveying means to stop said cleaned master in said initial position for recharging to repeat the operation.  
  2. The machine of claim 1 wherein said conveying means moves said master past first and second positions adjacent said path as said master is moved from said initial position around said path back to said initial position and wherein said control means causes said developing means to assume said first operative condition and said cleaning means to assume said second inoperative position upon a first revolution of said master around said first endless path and causes said developing means to assume said second inoperative condition and said cleaning means to assume said first operative position upon a second revolution of said master around said first endless path.  
  3. The machine of claim 1 wherein said cleaning means includes support means fixed with respect to said first endless path, linkage means pivotally carried by support means, a cleaning member carried by said linkage means for relative movement with respect to said support means as said linkage means is pivoted, and pivoting means for selectively pivoting said linkage means to cause said cleaning member to alternatively assume said first operative position to engage said master in said second position on said first endless path and assume said second inoperative position in which said cleaning member is spaced from and out of engagement with said master in said second position on said first endless path.  
  4. The machine of claim 3 wherein said support means further defines a passage therein having an inlet adjacent said cleaning member and an outlet spaced therefrom and wherein said cleaning means further includes vacuum producing means operatively communicating with said passage through said outlet, and filter means interposed between said outlet and said vacuum producing means and through which the vacuum in said passage is imposed.  
  5. The machine of claim 1 wherein said transfer means includes a conductive roller resiliently urged into contact with that side of said copy paper opposite the side in juxtaposition with said developed image to force said copy paper into intimate contact with said developed image, and transfer charging means for selectively imposing an electrostatic charge on said roller of a potential greater than the electrostatic charge of said developed image to effect transfer of said developed image onto said copy paper.  
  6. The machine of claim 5 wherein siad conveying means and said feed means simultaneously moves said copy paper and said master under said conductive roller while said charge is imposed thereon to effect transfer of said developed image from said master to said copy paper.  
  7. In a copy machine as set forth in claim 1 further including fusing means for fusing the transferred devel oped image on said copy paper thereonto to form a finished copy.  
  8. The machine of claim 1 wherein said control means further includes a conveyor starting switch having an actuator assembly and a lug carried by said lens and light assembly and operatively associated with said actuator assembly, said switch located adjacent the initial position of said lens and light assembly and said actuator assembly comprising:  
 an actuator for operating said switch;  
 a drive link pivoted on said actuator;  
 an abuttment on said actuator for limiting the pivotal movement of said drive link with respect to said actuator in a first pivotal direction; and,  
 resilient means for constantly urging said drive link in said first pivotal direction so that said lug pivots said drive link in a second pivotal direction opposite said first pivotal direction as said lens and light assembly moves away from said initial position in said first direction and moves said actuator and said drive link to operate said switch without pivoting said drive link with respect to said actuator as said lens and light assembly moves toward said initial position in said second direction.