US3269626A

US3269626A - Adjustable support for pressure fixing rollers

Info

Publication number: US3269626A
Application number: US355400A
Authority: US
Inventors: Otto J Albrecht
Original assignee: OMNITRONICS Inc
Current assignee: OMNITRONICS Inc
Priority date: 1964-03-27
Filing date: 1964-03-27
Publication date: 1966-08-30
Anticipated expiration: 1983-08-30
Also published as: NL6503647A; DE1277019B; GB1100758A

Description

Aug. 30, 1966 O. J. ALBRECHT 3,269,626

ADJUSTABLE SUPPORT FOR PRESSURE FIXING ROLLERS Filed March 27, 1964 IMAGE FIX/N6 DA-VELOP/NG .ST/iT/ON STAT/0N CHARGE 57'AT/O/V jazz/672227! 0520 J QZZreci' United States Patent 3,269,626 ADJUSTABLE SUPPORT FOR PRESSURE FIXING ROLLERS Otto J. Albrecht, Trenton, N..I., assignor to Omnitronics, Inc., Philadelphia, Pa., a corporation of Delaware Filed Mar. 27, 1964, Ser. No. 355,400 Claims. (Cl. 226-177) This invention is directed to an adjustable support for pressure fixing rollers in an electrostatic printing system, and more particularly to such a support system which provides a permanent, visible record on a flexible tape from a temporary but visible image represented by the adherence of conductive, opaque particles to discretely charged areas on the tape.

The progress of the computer arts has been such that the speed of computer operation now greatly exceeds the rate at which information can be fed into, and processed out of, the computer. Accordingly substantial efforts have been directed to increasing the eificiency and operating speed of those components which feed data into, and read the processed data out of, the computer itself. One significant improvement has been the production of electrostatic recording equipment, in which information is placed on a flexible tape by selectively charging different areas of the tape. The resultant latent image is rendered visible by passing the selectively charged tape through a mass of conductive opaque particles which adhere to the charged areas. The developed image is permanently fixed by the application of heat, pressure, solvent, or some combination of these or other techniques, to produce a permanent visible record of the information received from the computer or other data source.

Pressure fixing is frequently utilized with electrostatic printing systems to obviate stickiness or undesired adherence of the tape to the system elements, which may be caused by the use of heat and/or solvent fixing techniques. However there have been various shortcomings, even with pressure fixing systems, such as the need for precise alignment between the spaced-apart rollers which apply the pressure to the inked tape. The initial roller alignment is frequently lost after some hours of operation, because of the frequent engagement and disengagement of the rollers for loading and unloading the system, together with the relatively high pressure exerted between the rollers. In addition, tapes of different widths have been used in various systems, making it difficult to obtain a fixing pressure distributed evenly across the tapes of difierent widths.

It is, therefore, a primary object of the present invention to provide an improved pressure fixing arrangement in which an even and sure alignment between the rollers is provided initially, and is maintained with only minimum adjustment thereafter.

Another object of the invention is the provision of such a pressure fixing arrangement in which means are provided for simply and accurately presetting the pressure which will be applied to tapes of different widths, and distributed uniformly across the tape width.

The foregoing and other objects of the invention are realized, in one embodiment, by providing a pressure fixing arrangement which includes first and second rollers, positioned to either side of the tape path. Also provided is means, which may include a support frame, for supporting one of the rollers for movement toward and away from the other roller. In accordance with a salient aspect of the present invention, such means includes a novel pivot element or shaft of given cross section in a direction substantially normal to the direction of such movement, and a reduced cross section in a direction substantially parallel the direction of roller movement. This construction maintains alignment of the rollers as one roller is brought into engagement with the other roller. In addition, some give or fiexure is afforded by the pivot element being reduced in cross-section along the direction of such fiexure. Thus, a good contact between the two rollers is always assured, not only when the equipment is set up during manufacture, but also over the life of the equipment.

In accordance with another aspect of the invention, resilient biasing means may be provided to urge one of the rollers toward the other with the requisite level of pressure. To accommodate tapes of different widths, the biasing means may comprise two separate elements, individually adjustable to correspondingly regulate the pressure applied across two portions of one roller. The lateral extent of at least one biasing element is at least equal to the width of the most narrow tape to be used in the system, so that the pressure adjustment of the second biasing element can be varied with respect to that of the first to produce an even pressure across the entire tape width.

To enable those skilled in the art to practice the invention, the best mode contemplated for making and using the invention will now be described in connection with the accompanying drawing, in the several figures of which like reference numerals identify like elements, and in which:

FIGURE 1 is a block diagram of an electrostatic printing arrangement in which the present invention finds utility;

FIGURE 2 is a simplified front view of a pressure fixing arrangement constructed in accordance with the inventive teaching;

FIGURE 3 is a top view of the embodiment depicted in FIGURE 2;

FIGURE 4 is a partial side view of the structure shown in FIGURES 2 and 3, useful in understanding an important aspect of the present invention; and

FIGURES 5 and 6 are illustrative showings, similar to side views of the indicated components, but omitting portions of the support frame 25, for purposes of clarity in illustrating the flexing action of the outer portions of pivot shaft 26, useful in understanding the operation of the present invention.

General system As shown in FIGURE 1, an electrostatic printer 10 may be used to process a blank tape 11 drawn off va supply reel 12, to provide a visible and permanent image on the processed tape 13 which is wound on a take-up reel 14. A recorder or printing unit 10 in general comprises three sub-assemblies: a charge station 15, in which discrete areas of the flexible web are selectively charged to represent an information pattern; an image developing station 16 in which conductive opaque particles are attracted to the charged areas of the tape to develop the latent information pattern; and an image fixing station 17 in which the temporarily visible pattern is fixed to produce a permanent record of the information originally deposited on the tape at charge station 15. With this general perspective of the system, image fixing station 17 will now be considered.

Pressure fixing arrangement As shown in FIGURE 2, a pressure fixing station 17 is aflixed to a panel 20, which may be a portion of the front panel of an electrostatic printer. The fixer arrangement comprises a first roller 21 journalled on a shaft 22, which extends through panel 20 and is mounted in suitable bearings to be driven by a motor (neither the bearings nor the motor are indicated, in that their mounting and operation are well known) whenever the electrostatic printer is energized. Accordingly, to fix the temporarily visible image on the tape, it is necessary to force a second roller 23 toward roller 21, to provide a compressive force of a level sufiicient to effect the pressure fixing operation. Pressure roller 23 is journalled on a shaft 24, in its turn supported in a first end portion of frame member 25 positioned substantially normal to front panel 20. Frame member 25 includes a second end portion journalled on a shaft or pivot element 26 received in bearings 27 and 28 (FIGURES 36), but the bearing support is omitted to more clearly portray the inventive structure. A pair of set screws 39 are provided to lock shaft 26 tightly to support frame or carrier 25. It is thus apparent that support frame 25 can pivot about shaft 26, responsive to the selective application and removal of forces to the other end 30 of support frame 25.

A cantilever spring assembly 31 including a pair of bias elements or springs 32 and a second pair of shorter springs 33 is afiixed by a pair of screws 34 and a fastening plate 35 to end portion 30 of support frame 25. A rotatable, generally circular member 36 may be formed as a part of, or mounted on, a shaft 37 which is journalled in bearings (not shown) in front panel 20, to afford angular displacement of member 36 responsive to forces selectively ap plied to a handle member 38 aifixed to member 36 by screwing into a correspondingly tapped aperture in member 36, or afiixed by other suitable means. A pair of adjusting members 40 are provided, each of which has a spherical head portion 41 and a threaded body portion 42 which is received in a correspondingly tapped bore of member 36. A slot 43 is provided in the upper end of each member 40, to permit angular rotation of the member and a corresponding linear adjustment of the position of head portion 41 with respect to the surface of spring 32 when member 36 is in the position depicted in FIG- URE 2. A pair of nylon-tipped set screws 29 provide for selective locking of adjustment members 40 in position. The entire assembly of component 36 and its associated elements, together with springs 31 affixed to the left end of frame member 25, can be considered as a biasing means for effecting the engagement of pressure roller 23 with main drive roller 21.

From inspection of FIGURE 2, it will be apparent that upon effecting angular displacement of handle 38 in a clockwise or counter-clockwise direction, the head portions 41 of adjusting elements 40 will also be displaced in a like direction, out of engagement with the surfaces of springs 32, to remove the bias force from frame member 25. In a related manner, the compressive force between

rollers

23 and 21 can be restored by displacement of handle 38 in the counterclockwise or clockwise direction, to again engage extremities 41 with springs 32.

Certain of the components depicted in FIGURE 2 are also shown in FIGURE 3. The slots 43 for positioning adjusting members 40 are visible above the extensions of leaf spring surfaces 32.

In the right-hand portion of FIGURE 3, support frame 25 is shown to have a pair of support areas or

arms

45 and 46 in which the center portion of shaft 26 is received. The diameter of the center of shaft 26, where it is received in the bores of

support portions

45 and 46, is such that the shaft is tightly fitted to support frame 25 and set screws 39 lock the shaft to carrier 25. This construction assures that the rear portion of support frame 25 will always be in precise alignment with the center portion of shaft 26. Shaft 26 also includes a first outer leg portion 47, terminating in an end portion 48 which is received within a bearing member 28. The bearing support is not indicated in the drawing. In like manner, the other extremity of shaft 26 includes an outer leg portion 52 terminating in a rounded end portion 53, which is received in a bearing unit 27 supported within a bearing support (not shown) in conventional manner.

It is noted that

outer leg portions

47 and 52 of shaft 26 are of substantially the same cross section as the central portion in a plane, or in a direction, substantially =perpendicular to the direction of relative displacement between pressure roller 23 and main drive roller 21.

FIGURE 4 illustrates a salient aspect of the present invention, emphasizing the substantially reduced cross section of

outer leg portions

47 and 52 in a direction substantially parallel the direction of relative displacement between roller 23 and roller 21. By providing a solid central portion on shaft 26 received within bore or hearing

portions

45 and 46 of the support frame, support frame 25 is aligned with the central portion of shaft 26. However, by providing a reduced cross section in

outer leg portions

47 and 52 in the direction of flexure of support frame 25, unbalances of fixing pressure and/or surface irregularities of either

roller

23 or 21 which might otherwise cause unsatisfactory operation of the system, are precluded from adversely affecting the pressure-fixing operation.

The improved operation, and sureness of roller alignment, is best described in connection with FIGURES 5 and 6. Assuming, for purposes of explanation, that main drive roller 21 is out of round, at least along one surface (as indicated in FIGURE 5 in greatly exaggerated form), without the reduced-section outer legs of this invention, it would be expected that as pressure roller 23 were displaced into engagement with main drive roller 21, the left portions would engage and compress the tape therebetween, but effective pressure fixing would not be accomplished in the right hand portion of this assembly. However, in accordance with the inventive teaching and as particularly illustrated in FIGURE 6, the reduced crosssection outer legs of shaft 26 give or flex as the rollers are urged into engagement, thus to enable roller 23 to be aligned substantially flush with the adjacent surface of main drive roller 21 and ensure an effective pressure fixing operation across the complete lateral dimension of the tape as it passes between the rollers. This improved structure not only minimizes the time and expense required to effeet the original alignment of the pressure fixing arrange ment, but also provides for a long, trouble-free life of the equipment without constant attention to the critical relationship between these two rollers.

Another important aspect of the present invention is the ease and precision with which the system is compensated to provide an even pressure distribution across the width of the tape, especially when the system is changed over from operation with tape of a first Width to tape of a second width. For example, tape widths may vary from one-quarter inch to one and one-quarter inches in the lateral dimension.

Referring again to FIGURE 3, it is noted that the positions of members 40 can be adjusted by inserting a screwdriver or similar tool into slots 43 and effecting rotation of members 40, to correspondingly vary the level of the bias force transmitted over springs 32 to frame 25 and roller 23. The alignment means (not shown) for maintaining the tape in the proper position for fixing retains the tape with the inner tape edge always at the same position with respect to the front panel 20; such tape edge is coincident with broken line 60 shown in FIGURE 3. With the illustrated configuration, the upper one of the bias surfaces 32 (FIGURE 3) is arranged to transmit a force distributed evenly across the complete tape when the tape is of minimum width. The lower adjusting spring 32 is then regulated to provide a bias force which, when distributed across the remainder of the tape, will provide a substantially equal compressive force across the remainder of the mating surfaces between

rollers

23 and 21. By way of example, if a tape of one inch width were used, it is assumed that the three-quarter inch segment of the tape nearer to front panel 20 would be compressed by the force transmitted over upper spring 32. This adjustment is made in the manner described above, by inserting a tool such as a screwdriver in slot 43 and adjusting the position of the upper member 40 to effect the requisite force of a reference level transmitted over upper spring 32. A corresponding adjustment is then made to effect the transmission of a force one-third the reference level over the lower one of springs 32, in that this force will be applied to compress a one-quarter inch width of tape, only a third the lateral extent of the tape compressed by the force transmitted over the upper one of springs 32.

By readily accommodating tapes of various widths in the pressure fixer, considerable flexibility of this portion of the system is realized, and there is no restriction imposed on the overall system by the construction and operation of the pressure fixing stage.

By way of example, and in no sense by way of limitation, dimensions of a pivot element 26 successfully employed in practice of the invention are set out below. The overall shaft length was 2.5", and the center portion of the shaft, including those portions received in

support arms

45 and 46 of the support frame, was 1.625". The diameter of this center portion of pivot element 26, as well as the generally spherical

outer portions

48 and 53, was 0.3125". The extent of the reduced cross section

outer portions

47 and 52 was 0.150".

While only a particular embodiment of the invention has been described and illustrated, it is manifest that various modifications and alterations may be made therein. It is, therefore, the intention in the appended claims to cover all such modifications and alterations as may fall within the true spirit and scope of the invention.

What is claimed is:

1. In an electrostatic printing system in which a flexible tape having conductive particles adhering to individually charged areas is displaced along a given path, a pressurefixing arrangement comprising:

a first roller positioned to one side of the tape path;

a second roller positioned to the other side of the tape path; and

means for supporting one of said rollers for movement toward and away from the other of said rollers, including a shaft element comprising at least a portion which has a cross section of given dimension in a direction substantially normal to the direction of such movement, and a cross section smaller than said given dimension in a direction substantially parallel to the direction of movement, thereby accommodating irregularities in the roller surfaces and ensuring uniform pressure application between the rollers to provide uniform fixing of the image on the flexible tape.

2. In an electrostatic printing system in which a flexible tape having conductive particles adhering to individually charged areas is displaced along a given path, a pressurefixing arrangement comprising:

a first roller positioned to one side of the tape path;

a second roller positioned to the other side of the tape path; and a means for supporting one of said rollers for movement toward and away from the other of said rollers, including a pivot element having a central portion with a cross section of given uniform dimension, and a pair of outer portions coaxial with said central portion, each outer portion having a cross section smaller than said given dimension in a direction substantially parallel to the direction of roller movement,

thereby accommodating irregularities in the roller 65 surfaces and ensuring uniform pressure application between the rollers to provide uniform fixing of the image on the flexible tape.

3. In an electrostatic printing system in which a flexible tape having conductive particles adhering to individually charged areas is displaced along a given path, a pressurefixing arrangement comprising:

a first roller positioned to one side of the tape path;

a second roller positioned to the other side of the tape path;

0 movement, thereby accommodating irregularities in the roller surfaces and ensuring uniform pressure application between the rollers to provide uniform fixing of the image on the flexible tape.

4. In an electrostatic printing system in which a flexible tape having conductive particles adhering to individually charged areas is diplaced along a given path, a pressurefixing arrangement comprising:

a first roller positioned below the tape path;

a second roller positioned above the tape path;

a support frame, having a first end portion for supporting one of said rollers for movement toward and away from the other of said rollers, and a second end portion for receiving a pivot element; and

a pivot element having a central portion with a cross section of given uniform dimension positioned within the second end portion of the support frame, a pair of outer portions each with a cross section smaller than said given dimension in a direction substantially parallel to the direction of roller movement, and a pair of generally spherical bearing portions, one aflixed to the extremity of each outer portion of the pivot element, thereby accommodating irregularities in the roller surfaces and ensuring unifrom pressure application between the rollers to provide uniform fixing of the image on flexible tape.

5. In an electrostatic printing system in which a flexible tape having conductive particles adhering to individually charged areas is displaced along a given path, a pressurefixing arrangement comprising:

amain drive roller positioned below the tape path;

a pressure roller positioned above the tape path;

a support frame, having a first end portion for supporting the pressure roller for movement toward and away from the main drive roller, and a second por tion for receiving a pivot element;

first and second bearing supports, each spaced at a distance from, and aligned with, said second end portion of the support frame; and

a pivot element having a central portion with across section of given uniform dimension positioned within the second end portion of the support frame, and

having a pair of outer portions each with a cross section smaller than said given dimension in a direction substantially parallel to the direction of roller movement, each outer portion terminating in a generally spherical bearing portion which is received in one of said bearing supports, thereby accommodating irregularities in the roller surfaces and ensuring uniform pressure application betweenthe rollers to provide uniform fixing of the image on the flexible tape.

6. In an electrostatic printing system in which a flexible tape having conductive particles adhering to individually charged areas is diplaced along a given path, a pressurefixing arrangement comprising:

a first roller positioned to one side of the tape path;

a second rolled positioned to the other side of the tape path;

means for supporting one of said rollers for movement relative to the other of said rollers, including a pivot element having a cross section of given dimension in a direction substantially normal to the direction of such movement, and a cross section smaller than said given dimension in a direction substantially parallel to the direction of movement; and

resilient biasing means comprising at least two elements, each element being individually adjustable to relative to the other of said rollers, including a pivot element having a cross section of given dimension in a direction substantially normal to the direction of such movement, and a cross section smaller than said given dimension in a direction substantially parallel to the direction of movement;

biasing means comprising first and second resilient elements; and

at least two adjusting elements, one adjusting element positioned to engage the first resilient element and regulate the bias force applied across a first lateral portion of the area between the rollers, and the other adjusting element positioned to engage the second resilient element and regulate the bias force applied across a second lateral portion of the area between the rollers, thereby to provide a uniform fixing pressure for tapes of different widths.

8. In an electrostatic printing system in which a flexible tape having conductive particles adhering to individually charged areas is displaced along a given path, a pressurefixing arrangement comprising:

a first roller positioned to one side of the tape path;

a second roller positioned to the other side of the tape path;

means for supporting one of said rollers for movement relative to the other of said rollers, to provide a compressive force along a lateral area between the rollers; and

a single resilient biasing assembly comprising at least two integral elements, one of said elements being individually adjustable to regulate the compressive force only across a first portion of the lateral area and the other of said elements being individually adjustable to regulate the compressive force. only across the remaining portion of said lateral area, thereby to provide a uniform fixing pressure for tapes of different widths.

9. In an electrostatic printing system in which a flexible 8 pressive force along a lateral area between the rollers; a single biasing assembly, including first and second integral spring elements, positioned so that the first spring element applies a compressive force only regulate the fixing pressure across a portion of the along a first portion of said lateral area and so that tape, thereby to provide a uniform fixing pressure for the second spring element applies a compressive tapes of different widths. force only along the remaining portion of said lateral 7. In an electrostatic printing system in which a flexible area; tape having conductive particles adhering to individually at first adjusting means disposed to regulate the force charged areas is displaced along a given path, a pressure- 10 applied by the first spring element; and fiXillg g ment comprising: a second adjusting means disposed to regulate the force a first Teller Positioned to one side of the p P applied by the second spring element, thus to provide a second roller positioned to the other side Of the tape a uniform fixing pressure across said lateral area as P tapes of difierent widths are used in the system. means Supporting one Of Said rollers movement 10. In an electrostatic printing system in which a flexible tape having conductive particles adhering to individually charged areas is displaced along a given path, a pressure-fixing arrangement comprising:

a first roller positioned to one side of the tape path;

a second roller positioned to the other side of the tape path;

a frame member for supporting one of said rollers for movement relative to the other of said rollers, to provide a compressive force along a lateral area between the rollers; l

a first cantilever type spring having first and second end portions, said first end portion being secured to one end of the frame member;

a second cantilever type spring having first and second end portions, said first end portion being secured to said one end of the frame member;

shaft means having a central body portion spaced from the second end portion of each cantilever type spring; a first adjusting element, having a threaded body portion received in said shaft means and a head portion engaging the second end portion of the first cantilever type spring, the position of the first adjusting element in the shaft means determining the level of the bias force applied over the frame member to a first 40 portion of the lateral area between the rollers;

a second adjusting element, having a threaded body por- References Cited by the Examiner tape having conductive particles adhering to individually charged areas is displaced along a given path, a pressure- UNITED STATES PATENTS fixing arrangement comprising: 2,998,905 9/ 1961 Bieber 226-187 a first roller positioned to one side of the tape ath; 3,021,989 2/ 1962 Sellers 226-494 X a second roller positioned to the other side of the tape 3,073,590 1/1963 Romeo et a1 226-487 X path; means for supporting one of said rollers for movement relative to the other of said rollers, to provide a com- M. HENSON WOOD, 1a., Primary Examiner.

A, N. KNOWLES, Assistant Examiner.

Claims

8. IN AN ELECTROSTATIC PRINTING SYSTEM IN WHICH A FLEXIBLE TAPE HAVING CONDUCTIVE PARTICLES ADHERING TO INDIVIDUALLY CHARGED AREAS IN DISPLACED ALONG A GIVEN PATH, A PRESSUREFIXING ARRANGEMENT COMPRISING: A FIRST ROLLER POSITIONED TO ONE SIDE OF THE TAPE PATH; A SECOND ROLLER POSITIONED TO THE OTHER SIDE OF THE TAPE PATH; MEANS FOR SUPPORTING ONE OF SAID ROLLERS FOR MOVEMENT RELATIVE TO THE OTHER OF SAID ROLLERS, TO PROVIDE A COMPRESSIVE FORCE ALONG A LATERAL AREA BETWEEN THE ROLLERS; AND A SINGLE RESILIENT BIASING ASSEMBLY COMPRISING AT LEAST TWO INTEGRAL ELEMENTS, ONE OF SAID ELEMENTS BEING INDIVIDUALLY ADJUSTABLE TO REGULATE THE COMPRESSIVE FORCE ONLY ACROSS A FIRST PORTION OF THE LATERAL AREA AND THE OTHER OF SAID ELEMENTS BEING INDIVIDUALLY ADJUSTABLE TO REGULATE THE COMPRESSIVE FORCE ONLY ACROSS THE REMAINING PORTION OF SAID LATERAL AREA, THEREBY TO PROVIDE A UNIFORM FIXING PRESSURE FOR TAPES OF DIFFERENT WIDTHS.