US3514203A - Automatic toner replenisher - Google Patents

Description

May 26, 1970 A. s. ZERFAHS AUTOMATIC TONER REPLENISHER Original Filed May 11, 1964 3 Sheets-Sheet 1 INVENTOR ARTHUR $.ZERFAHS BY I ATTORNEY M y 26, 1970- A. s. ZERFAHS 3,514,203

AUTOMATIC TONER REPLENISHER Original Filed May 11, 1964 3 Sheets-Sheet 2 44 FIG. 2

INVENTOR ARTHUR 5. ZERFAHS BY JWM W ATTORNEY May 26, 1970 A. s. ZERFAHS AUTOMATIC TONER REPLENISHER Original Filed May 11, 1964 3 Sheets-Sheet 5 F 5&3. m m fi m? M m 5v 3n n II I I I l I I l I I I I I II I. A V w NR u mm B @mu NE. @W K ow 3:. W mm 02 I. mm m2 m2. a 31 m2. 05 N6 Sm 8m 3255 x e W e w -65 1| 4 -21 vmw wow a Q 0% 1 55 6 8 5 wmm ow vmm my H Ho? 5 H u r Q\ @NV ww u ATTORNEY United States Patent 3,514,203 AUTOMATIC TONER REPLENISHER Arthur S. Zerfahs, Elk Grove, Ill., assignor to SCM gor lioration, New York, N.Y., a corporation of New Original application May 11, 1964, Ser. No. 366,268, now Patent No. 3,330,179, dated July 11, 1967. Divided and this application May 17, 1967, Ser. No. 639,115

Int. Cl. G03g'15/I0 U.S. Cl. 355- 12 (Ilaims ABSTRACT OF THE DISCLOSURE An apparatus having a valve operated by the movement of copy paper through a photocopying machine for automatically replenishing pigment materials in the liquid developer or toner solution which is contained in a tank for developing the final image on the copy paper. A solenoid mechanism operated by the moving copy paper actuates the valve to deliver a solution of the pigment material from a storage container in amounts controlled by the length of the copy paper passing through the developer in the tank.

This application is a division of copending United States application Ser. No. 366,268 filed May 11, 1964, for Automatic Photocopying Apparatus now Pat. No. 3,330,179.

The present invention relates to duplicating machines such as electrostatic printers which use a liquid toner solution for making copies of original documents. The liquid toner solutions or liquid developers used in duplicating machines which make multiple copies of an original document basically comprise a dispersion of pigment particles in a high resistivity liquid carrier. The pigment particles may be coated with a fixer or charge control agent or other various additives. As the duplicating machine is used, the proportion of pigment particles in the solution diminishes since these particles are removed from solution on the image regions of the copy sheets. After several copies have been developed, the density of pigment particles on successive copy sheets may decrease thereby undesirably reducing the uniformity of the copies produced.

Accordingly a principal object of this invention is to provide a novel apparatus for automatically replenishing pigment materials in the liquid developer or toner solution used for developing the final image on a copy sheet.

A yet further object is to provide a novel means for automatically replenishing the developer that is responsive to the length of the copy paper that passes through the printer.

Further objects of the inveniotn will presently appear as the description proceeds in connection with the appended claims and the annexed drawings wherein:

FIG. 1 is a sectional view of an electrostatic printer embodying the automatic toner replenisher of the invention;

FIG. 2 is an enlarged partially schematic view of the automatic replenishing system;

FIG. 3 is a section taken substantially along lines 33 of FIG. 2; and

FIG. 4 is a schematic diagram of the sequencing and control circuit for the printer shown in FIG. 1;

Referring now to the drawings, and more particularly to FIG. 1, the reference numeral 20 generally designates an electrostatic printing machine comprising a casing 22 removably mounted on a rigid frame 23. Reference may be made to parent patent application Ser. No. 366,268 in which the printer 20 is disclosed in greater detail.

3,514,203 Patented May 26, 1970 Arranged within casing 22 is a copy paper supply compartment 24 comprising a shallow sheet metal tray into Which photoconductive paper may be loaded in a stack 25. A paper feed mechanism generally indicated at 26 removes sheets of the copy paper from stack 25 in compartment 24 and transports them one at a time through a corona charging unit 27 where a uniform charge of approximately 400 volts is applied to the surface of the copy paper. From charging unit 27, each sheet of copy paper is fed through an imaging station 28 located adjacent the lower end of an imaging projector 29.

The original document to be copied may be manually inserted through a horizontal slot 30' provided in a panel 32 which forms the front wall of casing 22. The document fed through slot 30 is conveyed through an imaging station 33. The copy paper is advanced through its imaging station 28 synchronously and in timed relation to the movement of the document through station 33.

Imaging station 33 is located below the forward end of imaging projector 29. Light is focused on imaging station 33 as by a pair of projection lamps 36' and 37, shown in FIG. 4, and an image is reflected from the surface of the original document into an objective lens 40 of projector 29 by a mirror 38. Lens 40 projects the reflected image onto the surface of the sheet of copy paper passing through its imaging station 28. As the image strikes the copy paper, the charge on the paper is reduced by an amount determined by the intensity of the reflected light. The black portions of the original will reflect such a relatively small light intensity as to affect the charge very little, while the light portions of the original will reflect sufficient light intensity as to almost completely release the latent electrostatic charge on the copy paper as is well known in the art.

With continued reference to FIG. 1, the exposed copy sheet containing, the latent charge pattern is developed to provide a visible image as by being passed through a developing tank 44. A liquid developer contained in tank 44 and having charged particles is applied to the latent image bearing surface of the copy paper. These charged particles, which may have a positive polarity, are attracted to negatively charged areas on the copy sheet to a degree determined by the charge at each region on the surface on the copy paper, thereby producing a graphic image. The copy paper feed mechanism then moves the developed copy paper between squeegee rollers 46 and 48 which remove the excess developer from the copy paper and which, if desired, may provide a direct voltage of relatively low magnitude to control the density of the image and/or the cleanliness of the background of the developed copy paper.

The sheets of copy paper deposited on surface 52 may be removed by an operator through an opening in panel 32.

Referring to FIGS. 1 and 4, the leading edge of the advancing document to be copied trips an actuator to close a further normally open switch 604 at the same time that it trips switch 596. Actuation of switch 604 to its closed position closes a circuit to another normally open switch 606 which is tripped to its closed position by the leading edge of the advancing document at the same time that switch 428 is opened. Switches 428 and 606 are tripped by the advancing document considerably before the trailing edge of the document clears the actuators of switches 426, 430, 574, 590, 596, and 604 with the result that switches 426, 430, 574, 590, 596 and 604 are held in their tripped positions when the document trips switches 428 and 606.

By closing switches 604 and 606 a circuit is completed to energize a winding 6080f a relay 610 in an energizing network for projection lamps 36 and 37, shown in FIG.

4. Energization of relay 610 closes two sets of normally open relay contacts 612 and 614 and opens switch 576. Contacts 612 and 614 are respectively connected in series with projection lamps 36 and 37 are illuminated by advancement of the document to be copied to the position along guide path 240 where it trips switch 606 after tripping switch 604.

As the copy paper emerges from imaging station 28 as shown in FIG. 1, it simultaneously trips two normally open switches 620 and 622 before entering tank 44. By closing switch 620, a 'further circuit, as shown in FIG. 4, is provided in parallel with the circuit through switches 604 and 606 for maintaining relay 610 energized. Shortly after switch 620 is tripped, the trailing edge of the original document clears the actuators of switches 426, 430, 574, 590, 596, and 604 where the original document and the sheet of copy paper are about the same length. As a result, switches 426, 574, 596, and 604 will open, and switches 430 and 590 will close. Although switch 604 opens at this time, projection lamps 36 and 37 remain illuminated as a result of the relay energizing circuit being completed by closing switch 620.

If the sheet of copy paper and the document are the same length, the trailing edge of the copy paper will clear the actuators of switches 432 and 586 at the same time that the trailing edge of the document clears the actuators of switches 426, 430, 574, 590, 596 and 604 with the result that switches 432 and 586 will respectively open and close at the same time that switches 426, 574, 596, and 604 open. Closing of switches 430 and 432 completes a circuit for energizing clutch for advancing the next sheet of copy paper in stack to rollers 65 and 100.

After the trailing edge of the original document clears the actuator of switch 596, corona unit 27 remains energized through switch 622 and a normally open switch 624. Switch 624 is connected in series with switch 622 and winding 598 and has an actuator which is positioned in document feed path 240 to be tripped to its closed position simultaneously with the actuation of switches 428 and 606. Corona unit 27 will remain energized as a result of the closing of switch 622 by the copy paper and the closing of switch 624 by the original document.

When the trailing edge of the original document clears the actuators for switches 428, 606, and 624, switch 624 will open to de-energize corona unit 27. Although switch 606 opens at this stage of the operation, relay 610 and, consequently, projection lamps 36 and 37, shown in FIG. 4 remain energized through switch 620.

As the copy paper which was advanced through corona unit 27 and imaging station 28 passes through tank 44, its trailing edge clears the actuator for switch 620, permitting this switch to open with the result that projection lamps 36 and 37 will turn off. The processed copy paper is advanced fromtank 44 to surface 52 where it may be removed from the printer as previously explained.

Referring now to FIG. 2, a mechanism 700 for automatically replenishing the toner pigment applied to the copy paper in tank 44 is shown to comprise a container 702 in which a liquid pigment particle solution is stored. Container 702 is suitably mounted on frame 23 and is formed with a cylindrical section 104 providing a liquid outlet port 706 for supplying the stored solution to tank 44.

With continued reference to FIG. 2, a valve member 708 is mounted in cylindrical section 704 for controlling flow of the solution through outlet port 706. Valve member comprises a cylindrical section 710 axially extending between radial flange portians 712 and 714 which respectively define opposed annular seating surfaces 716 and 718. Surfaces 716 and 718 are respectively adapted to seat against oppositely facing annular surfaces 720 and 722 formed in cylindrical section 704 at opposite ends of a straight through bore 724 which coaxially receives section 7.20 of valve member 708 and which establishes 4 fluid communication between the interior of the container 702 and outlet port 706.

Valve member 708, as shown in FIG. 2, is biased by a spring 726 to a position where surface 716 seats on surface 720 to block passage of the solution in container 702 through bore 724. The dimensions of bore 724 and valve member 708 are such that when surface 716 seats on surface 720, surface 718 is axially spaced below seating surface 722. When valve member 708 is lifted from the position shown in FIG. 4 against the bias of spring 726, the solution in container 702 will flow through bore 724 along longitudinal grooves 728 formed in section 710 until valve member 708 is raised to a position where surface 718 seats against surface 722. Thus in either its fully raised or fully lowered position, valve member 708 serves to block supply of solution to tank 44. As valve member 708 is rased from its position shown in FIG. 2 to its fully raised position, a metered predetermined amount of solution in container 702 is permitted to flow into tank 44 to replenish the tank solution with pigment.

To automatically operate valve member 708, an actuating arm 730, also shown in FIG. 2 is pivotally mounted on frame 23 by a pin 731 and has one end adapted to engage the lower end of member 708. By pivoting arm 730 in a clockwise direction, valve member 708 is lifted against the bias of spring 726. To pivot arm 730 for lifting valve member 708, a solenoid 732 (FIGS. 2 and 4) is suitably mounted on frame 23 and has one terminal connected to conductor 437.

As shown in FIG. 4, the other terminal of solenoid 732 is connected by a conductor 733 to a contact 734 of a two position manually operated, spring loaded pushbutton switch 736 and also to a switch blade 738 of a normally open switch 740. Switch blade 738 is adapted to engage a contact 742 which is connected by a conductor 744 to a further contact 746 of switch 736.

To manually operate the valve member 708 and with continued reference to FIG. 4, switch 736 has a leaf 748 normally engaging contact 746 to establish a circuit for energizing a solenoid 732 when switch 740 is closed. A pushbutton 735 suitably mounted on the switch 736 is depressible to actuate leaf 748 to engage contact 734 to thus complete a circuit for selectively energizing solenoid 732 through conductor 733. Energization of solenoid 732 attracts arm 730, causing it to pivot in a clockwise direction as viewed in FIG. 2 for lifting valve member 708 against the bias of spring 726.

With reference to FIGS. 2 and 4, switch 740 is actuated by a mechanism comprising a cam 754 nonrotatably mounted on a drive shaft 752 of a conventional timer motor 756. One motor winding terminal of motor 756 is, as shown in FIG. 4, connected to conductor 437. The other terminal of motor 756 is connected to a blade 758 of a two-position switch 760 having contacts 762 and 764.

Blade 758 normally engages contact 762 which is connected by a conductor 766 to a conductor 446 to energize motor 756 when switches 410, 422, and 424 are closed throught a current path that is in parallel with solenoid 732.

With continued reference to FIG. 4, contact 764 is connected to conductor 446 through switches 604 and 606 and also through switch 620. Thus, when switch blade 758 engages contact 764, motor 756 is energized to rotate cam 754 whenever relay 610 including winding 608 is energized to illuminate lamps 36 and 37.

As shown in FIG. 2, switch 760 is actuated by a spring leaf 768. A roller 770 mounted on leaf 768 is biased into engagement with the periphery of cam 754 which is formed with three circumferentially spaced apart notches 771, 772, and 774. When roller 770 is unseated from cam notches 771, 772, or 774 and rides high on the periphery of cam 754 switch blade 758 is urged into engagement with contact 764 to complete a circuit for energizing motor 756 whenever re ay 610 is energized.

When cam 754 is rotated to a position where roller 770 seats in any one of the notches 771, 772, or 774, switch blade 758 is moved into engagement with contact 762 to keep motor 756 energized through conductor 766. As a result, motor 756 cannot be de-energized when roller 770 is in any of the notches 771, 772, and 774 for a purpose to be explained shortly.

With continued reference to FIG. 2, switch 740 is actuated by leaf 7-68 and is closed to complete a circuit for energizing solenoid 732 whenever roller 770 seats in any of the cam notches 771, 772, and 774. Actuation of switch 740 is so adjusted that it closes after switch blade 758 engages contact 764 and opens before blade 758 disengages from contact 764. This insures that solenoid 732 is not held energized for objectionable, long periods of time. Owing to the previously described circuitry for energizing motor 756, it will be appreciated that cam 754 cannot be stopped in a position where roller 770 is seated in any one of the notches 771, 772, or 774 with the result that solenoid 732 cannot be continuously energized to permit an excessive amount of pigment to be supplied to tank 44.

As shown in FIG. 2, switches 760 and 740 are suitably mounted on a support plate 776 which is secured in place on frame 23. Motor 756 is mounted on plate 776 by any suitable means.

In operation of the printer 20, the switches 410, 422, and 424 must be closed before the document to be copied is fed into the printer 20. When switches 604 and 606 are closed by the advancing document, relay 610 is energized to illuminate exposure lamps 36 and 27. Closing of switches 604 and 606 also completes a circuit for energizing motor 756 through switch 760 with the result that cam 754 will be rotated. When roller 770 enters any one of the cam notches 771, 772, or 774, switch 740 closes to energize solenoid 732 through switch 736. Since an energizing circuit for motor 756 is maintained through engagement of switch blade 758 with contact 762 when roller 770 is seated in any of the cam notches 771, 772, or 774 cam 754 will continue to rotate, causing roller 770 to ride out of the cam notch to open switch 740. As a result, solenoid 732 will be pulsed each time roller 770 rides into one of the cam notches 771, 772 or 774.

By pulsing solenoid 732, arm 730 is momentarily attracted to lift valve member 708. When solenoid 732 is deenergized, spring 726 returns valve member 708 to the position shown in FIG. 2. As a result of displacing valve member 708 in this manner, a small predetermined amount of solution in container 702 is supplied to tank 44.

Motor 756, it will be noted, remains energized to continuously rotate cam 754 until the trailing edge of the document clears the actuator for switch 604 and the trailing edge of the copy paper clears the actuator for switch 620. Since switch 606 is closed at the time the copy paper is picked up by rollers 124 and 125, cam 754 will be continuously rotated for the period of time that the leading edge of the copy paper travels from rollers 124 and 125 to the actuator of switch 620'. Thereafter, cam 754 continues to be rotated depending essentially upon the length of the copy paper since the leading edge of the copy paper trips switch 620 to closed position and holds switch 620 in closed position until its trailing edge clears the actuator for switch 620. Thus, the amount of pigment supplied to tank 44 is made dependent on the length of copy. The length of copy paper, it will be appreciated, constitutes an approximate measure of the amount of pigment picked up by the copy paper in tank 44 and thus the amount of pigment that is required to be replaced.

The number of shots of solution supplied to tank 44 from container 7 02 may be adjusted by varying the speed of motor 756 or by changing the number of notches in cam 754. -If an additional amount of pigment is needed to replace that which is removed by the copy paper,

pushbutton 736 is manually depressed to swing leaf 748 into engagement with contact 734 for energizing solenoid 732 through conductor 733. When pushbutton 736 is released, this energizing circuit for solenoid 732 is interrupted by the return movement of leaf 748 into engagement with contact 746 where solenoid 732 is energized only when switch 740' is closed.

To effectively vary the number of notches in cam 754 in which roller 770 will seat, a plate 780, as shown in FIGS. 2 and 3, is mounted on the forward side of cam 754 by a pair of screws 782 and 784. Screws 782 and 784 extend through an arcuate slot 786 in plate 780 and are threadedly received in tapped bores (not shown) formed in cam 754. By loosening screws 782 and 784, plate 780 is adjustably swingable about the rotational axis of cam 754.

With continued reference to FIGS. 2 and 3, plate 780 is formed with an outer peripheral surface 788 Which is flush with the periphery of cam 754 and which has an elongated, circumferentially extending, outwardly opening recess 790. In the position of plate 780 shown in FIG. 7, recess 790 aligns with notch 772. The dimensions of plate 780 and of cam 754 are such that recess 790 will be disposed circumferentially between notches 772 and 774 when plate 780 is in its extreme counterclockwise adjusted position.

As best shown in FIG. 3, roller 770 projects beyond the forward side face of cam 754 so that its left-hand end portion rides along surface 788 of plate 780. By adjusting plate 780 to the position shown in FIG. 3 where recess 7 aligns with notch 772, roller 77 0 will ride into notches 771 and 772 but will not ride into notch 774. When plate 780 is swung to an extreme counterclockwise position where recess 790 is between notches 772 and 774, roller 770 only rides into notch 771 as cam 754 is rotated. By removing plate 780, roller 770 is permitted to ride into all three of the cam notches 771, 772 and 774. Thus it is clear from the foregoing that by adjusting or removing plate 780, the number of times solenoid 732 is pulsed and, consequently, the number of shots of solution supplied to tank 44 for each revolution of cam 752 may be selectively varied.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. In a duplicating machine the combination comprising means for producing an image on a sheet of copy paper including means providing for a supply of toner having developer particles adapted to produce a visible image on the sheet of copy paper and means for contacting the sheet -of copy paper with the toner to apply the developer particles to at least one surface of the said sheet of copy paper, and replenishing means for replenishing the supply of developer particles in said toner, said replenishing means being operable in response to a unidirectional actuating movement, and actuating means for actuating said replenishing means, said actuating means being operable in response to the movement of the sheet of copy paper through said machine for producing said unidirectional actuating movement for automatically actuating the replenishing means in accordance with the length of copy paper moving through said machine.

2. The duplicating machine defined in claim 1 wherein said supply of toner is in liquid form and is confined in a receptacle, and wherein said replenishing means for replenishing said supply of developer particles comprises a container for storing developer particles in liquid form, said container having an outlet port, and valve means controlling the flow of developer particles through said outlet port, said valve means being operable in response to said unidirectional actuating movement, and said actuating means being adapted for operating said valve means in accordance with the length of copy paper moving through said machine.

3. The duplicating machine defined in claim 2 comprising means for selectively adjusting the amount of the stored pigment particles in liquid form delivered to said receptacle in response to a predetermined length of copy paper passing into contact with said toner.

4. The duplicating machine defined in claim 1 wherein said replenishing means for replenishing said supply of developer particles comprises a container for storing developer particles in liquid form, said container having an outlet port for supplying said particles to said receptacle, and valve means controlling the flow of said developer particles from said container to said receptacle, said valve means being operable in response to said unidirectional actuating movement, and said actuating means being adapted for cyclically actuating said valve means between opened and closed positions a predetermined number of times in response to the movement of said copy paper dependent upon the length of the copy paper coming into contact with said toner.

5. The duplicating machine defined in claim 4 comprising means for adjusting the number of times said valve means is opened by said actuating means for a given length of copy paper.

6. In a duplicating machine, means for developing an image on a sheet of copy paper including means providing for a supply of toner having developer particles, said supply of toner being in liquid form and confined in a receptacle, and means for passing said copy paper into contact with said toner to apply the developer particles at least to one surface of said copy paper for producing a visible image thereon, and means controlled by the sheet of copy paper moving through said machine for automatically replenishing the supply of developer particles in said toner comprising a container for storing developer particles in liquid form and having an outlet port, valve means controlling the flow of developer particles through said outlet port and being operable in response to a unidirectional actuating movement, and means responsive to the movement of said copy paper through said machine for operating said valve means in accordance with the length of the said sheet of copy paper comprising switch means having an actuator so disposed in the path of the moving copy paper that said switch means is tripped by the leading edge of said sheet of copy paper and held in the tripped position until the trailing edge of said sheet of copy paper clears said actuator, and means for producing said unidirectional actuating movement in response to the tripping of said switch means for actuating said valve means to an opened position.

7. The duplicating machine defined in claim 6 comprising means including a lamp for providing at least one source of projection radiation for projecting the image of a document to be copied onto said copy paper before it contacts said toner, and means for energizing said lamp whenever said switch means is tripped by said copy paper.

8. In a duplicating machine, a duplicating station, guide means defining a path for routing a document to be copied through an exposure zone in said duplicating station, means for advancing said document along said path and for feeding copy paper through said duplicating station in timed relation with the movement of the document therethrough to enable the transfer of an image from said document to said copy paper as they pass through said duplicating station, and means for developing the image on said copy paper comprising a receptacle for confining a body of liquid toner having pigment particles adapted to make a visible image on the copy paper and means for passing the copy paper into contact with the toner after it passes through said duplicating station to apply the pigment particles to at least one surface of said copy paper, and means controlled by movement of said document and said copy paper for replenishing the supply of pigment particles in said toner.

9. The duplicating machine defined in claim 8 wherein said pigment particle replenishing means comprises a container for storing pigment particles in liquid form and having an outlet for supplying said solution to said receptacle, a normally closed valve for controlling flow of said pigment particles from said container to said receptacle, and means including first and second actuator means for operating said valve, said first actuator means being engaged by said document as it is advanced towards said exposure zone to open said valve, and said second actuator means being engaged by said copy paper as it moves away from said station to open said valve after said document disengages from said first actuator means.

10. The duplicating machine defined in claim 9 wherein said means for operating said valve further comprises means for cyclically opening and closing said valve as long as the document and copy paper respectively remain engaged with said first and second actuator means.

11. The duplicating machine defined in claim 10 wherein said second actuator means comprises a switch actuated by movement of said copy paper and wherein said means for cyclically operating said valve comprises a motor energized by actuation of said switch and means controlled by energization of said motor for effecting operation of said valve.

12. The duplicating machine defined in claim 1 wherein said toner is in liquid form and wherein the developer particles which are provided for replenishing the supply of particles in said toner are in liquid form.

References Cited UNITED STATES PATENTS 3,195,430 7/1965 Young 355-10 3,282,177 11/1966 Stanton 35510 3,352,218 11/1967 Ostensen 355-3 NORTON ANSHER, Primary Examiner .L. H. McCORMICK, 1a., Assistant Examiner US. Cl. X.R. 117--37

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