US1958885A - Facsimile printer - Google Patents

Facsimile printer Download PDF

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Publication number
US1958885A
US1958885A US562877A US56287731A US1958885A US 1958885 A US1958885 A US 1958885A US 562877 A US562877 A US 562877A US 56287731 A US56287731 A US 56287731A US 1958885 A US1958885 A US 1958885A
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US
United States
Prior art keywords
printing
bar
armature
printing member
impedance
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US562877A
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English (en)
Inventor
Carlisle Richard Wallace
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Westinghouse Electric Corp
Original Assignee
Westinghouse Electric Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to BE390959D priority Critical patent/BE390959A/xx
Application filed by Westinghouse Electric Corp filed Critical Westinghouse Electric Corp
Priority to US562877A priority patent/US1958885A/en
Application granted granted Critical
Publication of US1958885A publication Critical patent/US1958885A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/12—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using the sheet-feed movement or the medium-advance or the drum-rotation movement as the slow scanning component, e.g. arrangements for the main-scanning
    • H04N1/16—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using the sheet-feed movement or the medium-advance or the drum-rotation movement as the slow scanning component, e.g. arrangements for the main-scanning using a rotating helical element

Definitions

  • My invention relates to printing apparatus designed for the reproduction of pictures, printed matter and the like wherein the apparatus is made responsive to electric currents of intensities which vary with the degree of intensity of the elements comprising the matter to be reproduced.
  • Apparatus of this type is generally referred to as facsimile printers. More particularly, my invention is limited to improvements in apparatus of the above type, these improvements centering about the printing element and its associated structure.
  • My invention is particularly adapted to an apparatus of yet another type well known in the art wherein the received current pulses are transformed into interpretive symbols by means of pressure brought to bear upon message paper which is maintained in contact with transfer paper of the coated-carbon species or the like.
  • message paper in contact with carbon is caused to travel over a rotatable drum upon the surface of which is provided a helical rib.
  • a printing member which customarily assumes the form of a knife-edged bar of a length suflicient to span the width of the paper which is usually fed over the drum from rolls.
  • the printing element In response to current impulses received by the apparatus from a transmitter, the printing element is caused to vibrate and strike the paper, at each vibrationQagainst the helical rib, resulting in an impression being registered thereon from the carbon paper at the point defined by the intersection of the helix and the printing member at that moment. In this manner, subject-matter being sent out from some transmitting source, may be duplicate of the original.
  • the printing member comprising a bar extending across the width of the message paper and means
  • the amplitude response of the printing member shall be uniform and independent of the range of frequencies to which the apparatus is designed to respond.
  • the structure described above, as constituting prior art, is obviously too insensitive for the successful operation of the same; that is, from the viewpoint of obtaining uniform amplitude response to the frequencies received in apparatus of the type referred to.
  • Another object of my invention is to provide in a printing apparatus of the type referred to, a printing member which shall be free from reflected waves normally produced in a vibrating member.
  • Another object of my invention resides in the provision of means for limiting the striking distance of the printing member in an apparatus of the type described to eliminate the undesired results normally obtained by reason of the printing member bouncing upon the helical rib.
  • I provide a specially designed printing member and caused it to be operated by means of a driving motor associated with the printing member at one of its extremities, through the instrumentality of a specially designed coupling
  • the location of the driver at one extremity of the printing member is designed to transmit the vibrational energy through the printing member by a torsional twisting of the same.
  • Figure 1 is a view, in perspective, of that much 1of a printing apparatus wherein lies my invenion.
  • Fig. 2 is a bottom plan view of the structure illustrated in Fig. 1.
  • Fig. 3 is a plan view of the driving mechanism.
  • Fig. 4 is a plan view of the driving mechanism, the armature-restoring-spring holder being removed.
  • Fig. 5 is a side elevational view of the driving mechanism.
  • Fig. 6 is a view, in perspective, of the vibrating mechanism of the driving motor, showing the manner of connection to the printing member.
  • the apparatus comprises a drum 1 mounted on a shaft 3, the ends of the drum being provided with sprocket teeth 5 to engage message paper 7 in contact with carbon paper 9 and cause the same to be carried at a slow velocity underneath the printing member or bar 11 which is maintained in close proximity to the drum.
  • the papers may alternatively be pulled through by rubber rollers as in a typewriter.
  • a pinion 13 mounted on the shaft 3 adjacent to one end of the drum, is coupled to a driving motor (not shown) to cause rotation of the drum at a predetermined speed.
  • Mounted upon a surface of the drum is a helical rib 15 which extends around the surface of the drum except for an angular portion of approximately 20 which is maintained free for framing purposes.
  • the rib 15 is of suflicient height to make contact with the paper as it is drawn around under the printing member by rotation of the drum and may consist of a steel wire .010 to .030 inch diameter.
  • the printing member 'or printer bar 11 comprises a small strip of hard metal of a length sufiicient to span the width of the paper and is quite stiff.
  • the printer bar is mounted upon a hinge member 17 which comprises a very thin strip of spring metal attached, preferably, along the full length of the bar and may be soldered or otherwise integrally united thereto.
  • the printing member is permanently aflixed to a rigid bracket 19 of L-shape, extending parallel thereto, by screws or other connecting means extending through the hinge and engaging the bracket.
  • a bracket 21 of U-shape, to which the L- shape bracket is affixed, constitutes means, by reason of it being mounted upon a shaft or axle 23, whereby the printing member 11 may be lifted from its position in close proximity to the drum, so that the message paper may readily be inserted or removed.
  • the short arm of the L-shape bracket 19 provides supporting means whereby the driving unit 25 may be mounted in the desired position relative to the printing member 11.
  • the driving means comprises a vibrator assembly mounted upon. a base plate 2'1, this base plate being attached to the bracket 19 in the position illustrated.
  • a magnetic circuit comprises a horseshoe magnet 29, preferably of the permanentmagnet type, having removable pole pieces 31 and 33 of U-shape, the whole metallic structure being clamped to the base plate 27 by means of bolts or other suitable attaching means.
  • Between the pole pieces . is provided an armature 35 and suspension means 36 surrounded by a plurality of coils 37 and 39 which are maintained in fixed position by spacing elements 41 of insulating material. be fed by the incoming current impulses; and by means of the resulting reactions with the flux of the permanent magnet, they are adapted to cause the armature to vibrate in response to the incoming current.
  • the coils are adapted to A means is provided for damping the vibration of the armature for the purpose which will be more clearly described subsequently.
  • the damping means comprises a pad 43 of resilient material, such as rubber, mounted in a holding member 45 which is flxedly mounted on the magnetic structure.
  • the armature 35 comprises a substantially rectangular metallic member having an extended projection 47 which is designed to extend to and be embedded in, the damping pad 43.
  • the armature may be suspended by a flexible spring member 49 which is supported from an adjustable supporting means 51 mounted upon one of the magnetic pole pieces.
  • This member comprises an element provided with a groove 53 on its under surface which is in slidable engagement with a ribbed member 55, also mounted on the pole structure.
  • One end of the adjustable member 51 is slit, the slit 57 terminating in a circular opening 59 through the member into which may be inserted the armaturesuspension means 36 which may be clamped therein by means of a clamping bolt 61 engaging the split ends of the adjustable member in such manner as to draw them together, when desired.
  • the adjustable means just described may be employed for centering the armature in its correct position relative to the coils and the pole pieces.
  • a driving motor is shown mounted on the bracket in such position as to bring the armature and its suspension means in substantially axial alignment with the printing member, to which member the suspension element may be permanently connected.
  • the printing member is so designed as to have characteristics analogous to that of a transmission line, and the armature and its suspension means are designed to have characteristics to match this line.
  • the respective impedance of the pertinent elements may be determined as follows:
  • the characteristic impedance of the driver is The inertia per unit length of the line is for a strip, ,1
  • M mass per unit length h :width of strip
  • the compliance per unit length is the ratio of the angular deformation in radians to the ap
  • G modulus of shear in dynes per sq. cm.
  • Respective elements therefore having matched impedances, will be capable of responding equally to all frequencies within a predetermined range.
  • the vibrational waves set up in the printing member will be reflected back and either coincide with or oppose the starting of another wave.
  • This phenomenon known as reflection, will have the effect of changing the apparent impedance of the member for the various frequencies to which it is designed to be resonant.
  • it is necessary to provide means for absorbing the excess energy which is normally embodied in the reflected wave.
  • damping means may take the form of a pad of.resilient material, such as rubber, similar to that disclosed in the description of the driver, and may be mounted at the extremity of the printing member farthest from the driving motor.
  • a damping member When a damping member is employed for the purpose described, it may be considered as comprising a portion of the total impedance of the printing member, in which case, the impedance of the printing member may be reduced by an amount equal to the impedance offered by the damping member.
  • the impedance of the driving unit will be made to match with the combined impedances of the printing member and damping means.
  • the rubber damping member may be loaded with particles of heavy foreign material, such as powdered tungsten, lead oxide or the like, to increase the damping effect, prevent rebound, and prevent the printing member from over shooting the helix in case it be set in vibration during the time when the angular framing portion of the drum is passing beneath the printing member.
  • the impedance of the printing assembly is sufiioiently high, so that its path of travel will be just sufficient to reach the edge of the helix.
  • the range of frequencies to which the apparatus must be capable of responding with equal efiiciency is determined from the size of the picture and the number of scanning lines and dots per second desired. Knowing this, the moment of inertia of the armature and the compliance of the suspension stem may be calculated, placing the natural period of the stiflly suspended armature at the upper end of the frequency range desired. Suitable dimensions may be chosen for the armature which will give light weight consistently with good magnetic efliciency, as well known in the art of designing magnetic drivers for loud speakers.
  • I have, accordingly, disclosed, in detail, the improvements in printing apparatus which constitute my invention.
  • I provide means, in the form of a simple structure, whereby well defined reproductions of transmitted views may be obtained by reason of the fact that, in the apparatus described by me, I have eliminated the causes of the poor results obtained in apparatus of the prior art.
  • a still printer bar In a facsimile printing apparatus, a still printer bar, a fixed member, and means yieldably connecting said bar to said member substantially along the entire length of said bar and means for driving said bar.
  • a stiff printer bar In a facsimile printing apparatus, a stiff printer bar, a fixed member and means yieldably connecting said bar to said member substantially along the entire length of said bar, and means for driving said bar in the printing direction only.
  • a printing bar and means for actuating said bar comprising an armature, said armature being substantially coaxial with said bar.
  • a printing bar In a printing apparatus, a printing bar, an armature assembly associated therewith, the mechanical impedance of said bar being substantially equal to the mechanical impedance of said assembly.
  • a printing bar a printing bar, damping means therefor, an armature assembly associated with said bar for actuating the same, the mechanical impedance of said bar and damping means being substantially equal to the mechanical impedance of said armature assembly.
  • a printing bar means for actuating said bar in response to direct current and current at audio frequencies, the mechanical impedance of said bar being substantially constant over a wide range of frequencies.
  • a printing bar In a printing apparatus, a printing bar, means for actuating said bar in response to current at audio frequencies, and damping means associated with said bar and actuator for preventing resonances and reflections from establishing themselves therein.
  • a printer bar In a printing apparatus, a printer bar, a drum, a, helix thereon for movement relative to said bar and in close proximity thereto, means for actuating said bar toward said helix, the impedance of said bar being of such value as to prevent overshooting with the helix removed.
  • a printing element and actuating means therefor, said actuating means operating at one end of said printing element to set up torsional stresses in said printing element.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Accessory Devices And Overall Control Thereof (AREA)
US562877A 1931-09-15 1931-09-15 Facsimile printer Expired - Lifetime US1958885A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
BE390959D BE390959A (enrdf_load_stackoverflow) 1931-09-15
US562877A US1958885A (en) 1931-09-15 1931-09-15 Facsimile printer

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US562877A US1958885A (en) 1931-09-15 1931-09-15 Facsimile printer

Publications (1)

Publication Number Publication Date
US1958885A true US1958885A (en) 1934-05-15

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Application Number Title Priority Date Filing Date
US562877A Expired - Lifetime US1958885A (en) 1931-09-15 1931-09-15 Facsimile printer

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US (1) US1958885A (enrdf_load_stackoverflow)
BE (1) BE390959A (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2415229A (en) * 1942-09-10 1947-02-04 Rca Corp Facsimile apparatus
US2421781A (en) * 1941-05-24 1947-06-10 Borg George W Corp Watch timing recorder
US2592567A (en) * 1947-08-04 1952-04-15 Faximile Inc Facsimile recorder
US3647356A (en) * 1970-02-13 1972-03-07 Motorola Inc Printer drive with page record feed

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2421781A (en) * 1941-05-24 1947-06-10 Borg George W Corp Watch timing recorder
US2415229A (en) * 1942-09-10 1947-02-04 Rca Corp Facsimile apparatus
US2592567A (en) * 1947-08-04 1952-04-15 Faximile Inc Facsimile recorder
US3647356A (en) * 1970-02-13 1972-03-07 Motorola Inc Printer drive with page record feed

Also Published As

Publication number Publication date
BE390959A (enrdf_load_stackoverflow)

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