US3873986A - Recording needle protection arrangement for facsimile recorder - Google Patents

Recording needle protection arrangement for facsimile recorder Download PDF

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Publication number
US3873986A
US3873986A US465794A US46579474A US3873986A US 3873986 A US3873986 A US 3873986A US 465794 A US465794 A US 465794A US 46579474 A US46579474 A US 46579474A US 3873986 A US3873986 A US 3873986A
Authority
US
United States
Prior art keywords
drum
cutout
recording
recording needle
improvement
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
US465794A
Other languages
English (en)
Inventor
Toshihiko Misawa
Mitsuru Kondo
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.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
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
Application filed by Ricoh Co Ltd filed Critical Ricoh Co Ltd
Application granted granted Critical
Publication of US3873986A publication Critical patent/US3873986A/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
    • H04N1/06—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 cylindrical picture-bearing surfaces, i.e. scanning a main-scanning line substantially perpendicular to the axis and lying in a curved cylindrical surface
    • H04N1/08—Mechanisms for mounting or holding the sheet around the drum
    • H04N1/0804—Holding methods
    • H04N1/0813—Holding sides of the sheet which are substantially parallel to the drum axis
    • 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
    • H04N1/06—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 cylindrical picture-bearing surfaces, i.e. scanning a main-scanning line substantially perpendicular to the axis and lying in a curved cylindrical surface
    • H04N1/08—Mechanisms for mounting or holding the sheet around the drum
    • 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
    • H04N1/06—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 cylindrical picture-bearing surfaces, i.e. scanning a main-scanning line substantially perpendicular to the axis and lying in a curved cylindrical surface
    • H04N1/08—Mechanisms for mounting or holding the sheet around the drum
    • H04N1/083—Holding means
    • H04N1/0839—Mechanical clamps, i.e. means for holding the sheet against the drum by mechanical force

Definitions

  • the present invention relates to an improved facsimile recorder arranged to prevent damage of the recording needle caused by abutment thereof with an edge of a cutout provided in a clamp which secures the copy sheet to the drum.
  • the clamp is formed with cutouts to prevent interference of the clamp with releasing pawls or guides which remove the copy sheet from the drum. It has been found in practice using this type of automatic facsimile receiver that the recording needle is sometimes damaged when it drops into one of the cutouts through engagement with an edge of the cutout caused by the longitudinal feed of the recording needle.
  • FIG. 1 is a fragmentary side sectional view of a facsimile recorder to which the present invention is directed shown in a copy sheet insertion condition;
  • FIG. 2 is similar to FIG. 1, but shows the facsimile recorder in a copy sheet removal condition
  • FIG. 3 is a fragmentary top view of a prior art arrangement of the facsimile recorder of FIG. 1;
  • FIG. 4 is similar to FIG. 3, but illustrates the improvement according to the present invention.
  • FIG. 5 is an enlarged diagrammatic view of part of FIG. 4 illustrating the geometry of the improvement of the present invention.
  • a facsimile recorder or re-' DC to which the present invention is directed includes a rotary drum l0 rotated by driving means (not shown) in the direction of an arrow A and being provided with at least one clamp or pinching pawl 12 to secure a recording medium in the form of a sheet 14 to the drum 10.
  • a recording instrument here shown as a recording needle 16 is moved parallel to the axis of the drum 10 by a lead screw (not shown) driven by the driving means to reproduce the transmitted original document on the sheet 14.
  • the recording needle 16 is energized by an electronic receiving unit (not shown) to continuously vary the density of the image formed thereby on the sheet 14.
  • an operating handle 18 When an operating handle 18 is rotated in the direction of an arrow B, it engages with the pawl 12 to rotate the same clockwise so that a gap is formed between the pawl 12 and the circumference of the drum 10.
  • the leading edge of the sheet 14 is inserted into the gap, and the handle .18 is rotated in a direction opposite to that of the arrow B to the position shown in FIG. 2, and the pawl 12 is rotated counterclockwise by a spring (not shown) to clamp the leading edge of the sheet 14 to the drum l0 and thereby secure the sheet 14 to the drum 10.
  • the drum'10 is then rotated in the direction of the arrow A many times as the recording needle 16 is driven parallel to the axis of the sheet 14 so that the locus of the recording needle 16 on the drum 10 is a helix of very small lead compared to the length of the drum 10 so that many closely spaced lines are drawn on the sheet 14 to provide a copy of satisfactory resolution.
  • a roller 20 is provided to guide the sheet 14, and a guide member or releasing pawl 22 is movable into engagement with the surface of the drum 10 to release and guide the sheeet 14 from the drum 10 after a recording operation is completed.
  • a releasing arm 24 is normally biased in the direction of an arrow C by a tension spring 26 out of engagement with the pawl 12, but is manually or automatically movable in the direction of an arrow D before the leading edge of the sheet 14 reaches the pawl 22 to rotate the pawl 12 clockwise to release the leading edge of the sheet 14. Thereafter, the sheet 14 will be removed from the drum 10 and be ejected from the recorder in the direction of an arrow E.
  • FIG. 3 shows a prior art arrangement of the pawls l2 and 22.
  • three separate pawls l2 and two pawls 22 may be provided, but the same results can be obtained using a unitary pawl 12 if it is suitably shaped.
  • a single pawl 12 is formed with cutouts 30 which are aligned with and appreciably wider than the pawls 22 so interference of the pawls 12 with the pawls 22 during rotation of the drum 10 is prevented.
  • An arrow F represents the direction of movement of the recording needle 16.
  • Modified cutouts 32 replace the cutouts 30, and each comprise a rectangular portion 320 which is essentially equivalent to the cutout 30 and a triangular portion 32b having a slanted edge 32c.
  • the angle between the direction of movement of the recording needle 16 and the slanted edge 320 is selected on the basis of the speed of rotation of the drum 10 and the lead of the recording needle 16 per revolution of the drum 10, so that said angle is less than the helix angle of the locus of the recording needle 16 on the drum 10.
  • the locus of the recording needle 16 on the drum 10 will always be leftward of the slanted edge 32c as shown because the locus of the point of intersection of a line passing through the recording needle 16 and oriented in the direction F with the slanted edge 32c will move rightward as shown faster than the recording needle 16.
  • the recording needle 16 it is impossible for the recording needle 16, to abut with the slanted edge 32c, even if the recording needle 16 drops into the cutout 32 from a point on the slanted edge 320.
  • the arrangement of the present invention effectively prevents damage to the recording needle 16 caused by abutment thereof with an edge of the cutout of the pawl 12.
  • FIG. shows the geometry of a cutout 32 in greater detail. It will be assumed that the pawl 12 is curved to be coaxially conjugate to the circumference of the drum 10. The depth d of the cutout 32 will then correspond to the arc length of the cutout 32 in the direction of rotation of the drum l0 represented in a plane.
  • a character 1 represents the displacement in the direction ofthe arrow F of the recording needle 16 during the interval in which the drum has rotated through an angle producing displacement equal to the depth d of the circumference of the drum 10.
  • the case shown is a limiting case in which the angle 6 between the direction of movement of the recording needle 16 and the slanted edge 32c is equal to the arctangent of the displacement 1 divided by the depth d of the cutout 32.
  • the angle 0 in this limiting case is equivilant to the helix angle of the locus of the recording needle 16 on the drum.
  • the angle 0 must be smaller than the helix angle, or expressed mathematically 0 arctan
  • a recording device having a rotary drum carrying a recording medium and a recording instrument movable along the circumference of the recording medium substantially parallel to the axis of the drum, the recording medium being secured to the drum by a clamp formed with a cutout to prevent interference of the clamp with a member for removing the recording medium from the drum, an improvement to prevent the recording instrument from being damaged by engaging with a side of the cutout of the clamp, the improvement being that the cutout has a slanted edge determined by the rotational speed of the drum and the speed of movement of the recording instrument.
  • the cutout has a rectangular portion and a triangular portion cornprising the slanted edge respectively arranged in the direction of movement of the recording instrument, the angle between the direction of movement of the recording instrument and the slanted edge of the triangular portion of the cutout being less than the arctangent of the depth of the cutout divided by the displacement of the recording instrument during an interval in which the drum has rotated through an angle producing displacement of the circumference of the drum substantially equal to the depth of the cutout.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Handling Of Cut Paper (AREA)
  • Facsimile Scanning Arrangements (AREA)
  • Fax Reproducing Arrangements (AREA)
  • Facsimiles In General (AREA)
US465794A 1973-05-08 1974-05-01 Recording needle protection arrangement for facsimile recorder Expired - Lifetime US3873986A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1973053919U JPS5313305Y2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1973-05-08 1973-05-08

Publications (1)

Publication Number Publication Date
US3873986A true US3873986A (en) 1975-03-25

Family

ID=12956108

Family Applications (1)

Application Number Title Priority Date Filing Date
US465794A Expired - Lifetime US3873986A (en) 1973-05-08 1974-05-01 Recording needle protection arrangement for facsimile recorder

Country Status (4)

Country Link
US (1) US3873986A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
JP (1) JPS5313305Y2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
DE (1) DE2421547C3 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
GB (1) GB1456605A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2514974A (en) * 1948-06-25 1950-07-11 Times Facsimile Corp Sheet holding mechanism for facsimile recorders and the like
US3618123A (en) * 1968-12-26 1971-11-02 Xerox Corp Facsimile drum conveyor

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2514974A (en) * 1948-06-25 1950-07-11 Times Facsimile Corp Sheet holding mechanism for facsimile recorders and the like
US3618123A (en) * 1968-12-26 1971-11-02 Xerox Corp Facsimile drum conveyor

Also Published As

Publication number Publication date
DE2421547A1 (de) 1974-11-28
JPS502222U (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1975-01-10
DE2421547B2 (de) 1978-05-11
DE2421547C3 (de) 1979-01-18
JPS5313305Y2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1978-04-11
GB1456605A (en) 1976-11-24

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