US3728019A - Auto-focus printing below 1,1 {33 {0 magnification - Google Patents

Auto-focus printing below 1,1 {33 {0 magnification Download PDF

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Publication number
US3728019A
US3728019A US00179745A US3728019DA US3728019A US 3728019 A US3728019 A US 3728019A US 00179745 A US00179745 A US 00179745A US 3728019D A US3728019D A US 3728019DA US 3728019 A US3728019 A US 3728019A
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US
United States
Prior art keywords
lens
magnification
bell crank
focus
negative
Prior art date
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Expired - Lifetime
Application number
US00179745A
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English (en)
Inventor
C Swing
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.)
Eastman Kodak Co
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Eastman Kodak Co
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 Eastman Kodak Co filed Critical Eastman Kodak Co
Application granted granted Critical
Publication of US3728019A publication Critical patent/US3728019A/en
Anticipated expiration legal-status Critical
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B27/00—Photographic printing apparatus
    • G03B27/32—Projection printing apparatus, e.g. enlarger, copying camera
    • G03B27/34—Means for automatic focusing therefor
    • G03B27/36—Means for automatic focusing therefor by mechanical connections, e.g. by cam, by linkage

Definitions

  • Another object of this invention is to provide automatic-focusing photographic apparatus which is rel'atively simple in construction and operation.
  • a more specific object of this invention is to provide automatic-focus photographic printing apparatus which extends through unity-magnification and uses a singular cam and-linkage to maintain the automatic focus.
  • Still another object of this invention is to provide automatic-focus photographic printing apparatus wherein the automatic-focus capability is continuous rather than incremental.
  • the printer operator changes the magnification factor by first varying the position of the magnifying lens with ject distance) and between the lens 15 and the plane 13 (i.e., image distance) are:
  • a cam and linkage connects the negative holder to the lens in a manner which automatically varies the negative to lens distance to maintain the sharp focus.
  • the cam and linkage operates solely to adjust the lens/negative distance based upon the magnification factor and therefore is relatively simple of design and construction.
  • FIG. 1 is a diagrammatic optical representation of photographic printing apparatus in which the present invention finds utility.
  • FIG. 2 is a side view in section of automatic-focus photographic printing apparatus according to the present invention.
  • FIG. 1 there is shown in diagrammatic form a photographic system including a negative plane 11 and an object plane 13 with a lens 15 interposed therebetween. Assuming a lens having a focal length f, to obtain a focused image at a magnification m, the proper distances along the optical axis 17 between the negative plane 11 and the lenslS (i.e., ob-
  • a negative carriage 21 and a lens carriage 23 are supported on a common guide bar 25.
  • the tops of the negative carriage and the lens carriage are connected by a constant tension spring 27 to eliminate any play in the apparatus.
  • the printer frame 29 includes a cam groove 31. Integral with the negative carriage 21 at the bottom thereof is a nest 33 in the form of a forked section extending down from the carriage.
  • a bell crank 35 is attached to and pivots on an arm 37 of the lens carriage 23.
  • the arm 39- of the bell crank 35 supports a cam follower bearing 41 which rides in the cam groove 31.
  • Another arm 43,0f the bell crank supports a negative carriage positioning bearing 45 which rides in the nest 33 of the negative carriage.
  • the negative focal plane 47 which is adapted to support a film negative.
  • the lens carriage 23 In the lens carriage 23 is supported a suitable lens array 49.
  • the optical centerline 51 passes through the center of the negative plane 47, the lens array 49 and impinges on the center of the image or print plane 53.
  • the cam groove 31 gradually slopes downwardly going from left to right until the knee 55 is reached, at which point the groove falls off rapidly.
  • the knee 55 represents the position of the cam follower bearing for unity magnification, with positions to the left of the knee conforming to magnifications in'excess of unity and positions to the right of the knee being magnifications less than unity.
  • the lens carriage 23 is moved relative to the print plane 53 to give a desired factor of magnification. Movement may be accomplished by any known motive means such as a chain belt drive or motor and drive screw.
  • any known motive means such as a chain belt drive or motor and drive screw.
  • the lens carriage is moved from left to right, the'cam following bearing 41 tracking in the cam groove 31 will move gradually downwardly as it approaches the knee 55 of the cam groove 31.
  • the downward movement of the bearing 41 in the cam groove 31 causes the bell crank 35 to be pivoted counterclockwise about the arm 37 of the lens carriage. Pivoting of the bell crank 35 in turn causes the negative carriage positioning bearing 45 to move in the nest 33 to move the negative carriage 21 relatively away from the lens carriage 23.
  • the conjugate distance will be decreasing the object distance and the image distance will be changing in the proper proportions to insure automatic focusing for a given magnification above unity.
  • the increasing separation between the negative carriage 21 and the lens carriage 23 is gradual until the point where the cam following bearing 41 reaches the knee 55 of the cam groove 31. At this point the cam following bearing 41 will move rapidly downwardly in the cam groove 31.
  • the configuration of the cam groove 31 is such that movement of the cam following bearing 41 to the right of the knee 55 will cause the separation between the lens carriage 23 and the negative carriage 21 to increase more rapidly than the decrease in separation between the lens carriage 23 and the print plane 53 so that the conjugate distance begins to increase to maintain automatic focusing for a given magnification below unity.
  • the object distance that is the distance between the lens and the negative
  • the lens focal length as the magnification approaches infinity. Therefore, the groove 31 of the cam of FIG. 2 flattens out as the magnification increases and the only limitation on the maximum magnification available with the apparatus according to the present invention, is on the length of the printer frame in which the cam groove is machined.
  • an automatic focusing drive mechanism operative to maintain said apparatus in focus for a continuous range of magnification varying from less than unity to substantially more than unity, saic; mechanism comprising:
  • first linear positioning means coupled to said lens carriage and operative to position said lens the required distance from said print plane to effect a given magnification
  • a bell crank having first and second arms, said bell crank being pivotallysupported by said support means;
  • bearing means supported on said first arm of said bell crank and connected to said second positioning means to control the position thereof;
  • cam groove means supported by said housing and cam follower means supported by said second arm of said bell crank and positioned to ride in said cam groove means whereby movement of said cam follower means in .said cam groove means upon movement of said lens by said first positioning means will cause rotation of said bell crank and corresponding movement of said bearing means to control the relative position between said lens carriage and said negative holder for the required distance to maintain focus or any selected magnification.
  • said second positioning means includes an arm extending from said negative holder, said arm having a nest in the end thereof vertically oriented with respect to the optical axis of said lens and wherein said bearing means rides in said nest.
  • L length of said magnifying lens
  • b may be calculated from the apparatus geometry by subtracting from the horizontal distance between back focus and pivot axis of said bell crank, the difference between the effective focal length of said magnifying lens divided by the selected magnification and the horizontal distance between said negative holder and the vertical centerline of said nest.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Variable Magnification In Projection-Type Copying Machines (AREA)
  • Projection-Type Copiers In General (AREA)
US00179745A 1971-09-13 1971-09-13 Auto-focus printing below 1,1 {33 {0 magnification Expired - Lifetime US3728019A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US17974571A 1971-09-13 1971-09-13

Publications (1)

Publication Number Publication Date
US3728019A true US3728019A (en) 1973-04-17

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
US00179745A Expired - Lifetime US3728019A (en) 1971-09-13 1971-09-13 Auto-focus printing below 1,1 {33 {0 magnification

Country Status (6)

Country Link
US (1) US3728019A (it)
CA (1) CA972602A (it)
DE (1) DE2244705A1 (it)
FR (1) FR2153948A5 (it)
GB (1) GB1402025A (it)
IT (1) IT967350B (it)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4135794A (en) * 1975-05-12 1979-01-23 Addressograph-Multigraph Corporation Photocomposition machine
US4140392A (en) * 1977-04-20 1979-02-20 Thomson-Csf Optical system for projecting patterns comprising a constant-magnification focusing servocontrol
US4215922A (en) * 1978-11-01 1980-08-05 Am International, Inc. Method for projecting characters at a selected point size in a photocomposition machine
KR20030010092A (ko) * 2001-07-25 2003-02-05 엘지니꼬동제련 주식회사 동슬래그를 함유한 콘크리트 벽돌 및 블럭
KR20030080270A (ko) * 2002-04-04 2003-10-17 엘지니꼬동제련 주식회사 동슬래그를 함유한 콘크리트

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3922512A1 (de) * 1989-07-08 1991-01-17 Kodak Ag Vorrichtung zum umwandeln von lichtsignalen in videosignale
US5450175A (en) * 1993-07-27 1995-09-12 Konica Corporation Image forming apparatus having optical means for image magnification change

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1399347A (en) * 1920-08-11 1921-12-06 August F Jobke Focusing device
US1677778A (en) * 1922-09-20 1928-07-17 Johannes Robert Carl August Automatic focusing optical-projection apparatus
US1986693A (en) * 1932-02-09 1935-01-01 Firm Uhertype A G Photographic type composing
US2430252A (en) * 1945-05-01 1947-11-04 Simmon Brothers Inc Auto-focus enlarger
US2568762A (en) * 1948-12-08 1951-09-25 Fed Mfg & Engineering Corp Autofocus enlarger
US3213748A (en) * 1961-02-16 1965-10-26 Durst Ag Automatic focusing arrangement for enlarging apparatus

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1399347A (en) * 1920-08-11 1921-12-06 August F Jobke Focusing device
US1677778A (en) * 1922-09-20 1928-07-17 Johannes Robert Carl August Automatic focusing optical-projection apparatus
US1986693A (en) * 1932-02-09 1935-01-01 Firm Uhertype A G Photographic type composing
US2430252A (en) * 1945-05-01 1947-11-04 Simmon Brothers Inc Auto-focus enlarger
US2568762A (en) * 1948-12-08 1951-09-25 Fed Mfg & Engineering Corp Autofocus enlarger
US3213748A (en) * 1961-02-16 1965-10-26 Durst Ag Automatic focusing arrangement for enlarging apparatus

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4135794A (en) * 1975-05-12 1979-01-23 Addressograph-Multigraph Corporation Photocomposition machine
US4140392A (en) * 1977-04-20 1979-02-20 Thomson-Csf Optical system for projecting patterns comprising a constant-magnification focusing servocontrol
US4215922A (en) * 1978-11-01 1980-08-05 Am International, Inc. Method for projecting characters at a selected point size in a photocomposition machine
KR20030010092A (ko) * 2001-07-25 2003-02-05 엘지니꼬동제련 주식회사 동슬래그를 함유한 콘크리트 벽돌 및 블럭
KR20030080270A (ko) * 2002-04-04 2003-10-17 엘지니꼬동제련 주식회사 동슬래그를 함유한 콘크리트

Also Published As

Publication number Publication date
IT967350B (it) 1974-02-28
GB1402025A (en) 1975-08-06
DE2244705A1 (de) 1973-03-22
CA972602A (en) 1975-08-12
FR2153948A5 (it) 1973-05-04

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