CH612016A5 - Photographic copier for which the ratio of the image size to the object size is adjustable - Google Patents
Photographic copier for which the ratio of the image size to the object size is adjustableInfo
- Publication number
- CH612016A5 CH612016A5 CH998176A CH998176A CH612016A5 CH 612016 A5 CH612016 A5 CH 612016A5 CH 998176 A CH998176 A CH 998176A CH 998176 A CH998176 A CH 998176A CH 612016 A5 CH612016 A5 CH 612016A5
- Authority
- CH
- Switzerland
- Prior art keywords
- holder
- bridge
- ratio
- opposite corners
- size
- Prior art date
Links
Classifications
-
- 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
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Lens Barrels (AREA)
- Variable Magnification In Projection-Type Copying Machines (AREA)
Abstract
The apparatus comprises a fixed film-holder (1), a lens-holder (2) and a document-holder (3), the lens-holder being adjusted manually into the position corresponding to the required ratio n, while the document-holder is locked (slaved) to the control-circuit mounting. The control circuit comprises a Wheatstone bridge (8) and an amplifier (15) with two inputs connected respectively to the first and second opposite corners (13, 14) of the Wheatstone bridge and with an output connected, via a reversing switch (17), to the correction motor (5). The third and fourth opposite corners (18, 19) of the bridge are connected respectively to the ends of a potential divider bridge comprising two resistors (21, 22) in series, each having the value F OMEGA . The junction point of these two resistors is connected to an input of a comparator (23) whose other input is connected to one (13) of the first and second opposite corners of the bridge, the output of this comparator being connected to the reversing switch in order to reverse the polarity of the error signal applied to the motor by the amplifier when the ratio n passes from a value greater than 1 to a value less than 1, or vice versa. <IMAGE>
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7524622A FR2320571A1 (en) | 1975-08-07 | 1975-08-07 | Photocopier with servo motor and wheatstone bridge circuit - using wheatstone bridge instead of limit switches for direction reversal |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CH612016A5 true CH612016A5 (en) | 1979-06-29 |
Family
ID=9158879
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CH998176A CH612016A5 (en) | 1975-08-07 | 1976-08-05 | Photographic copier for which the ratio of the image size to the object size is adjustable |
Country Status (4)
| Country | Link |
|---|---|
| CH (1) | CH612016A5 (en) |
| DE (1) | DE2633708A1 (en) |
| FR (1) | FR2320571A1 (en) |
| IT (1) | IT1066935B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6029099B2 (en) * | 1980-02-25 | 1985-07-09 | 大日本スクリ−ン製造株式会社 | Method and device for changing the common focus projection magnification of a projection device |
| CH658325A5 (en) * | 1982-01-21 | 1986-10-31 | Rudolf Boehme | Enlarger WITH STEADY FOCUSING ON MODIFICATION OF SCREEN SIZE BY ONE, ON A bridge circuit and an amplifier, CONTROLLED LENS. |
-
1975
- 1975-08-07 FR FR7524622A patent/FR2320571A1/en active Granted
-
1976
- 1976-07-27 DE DE19762633708 patent/DE2633708A1/en not_active Withdrawn
- 1976-08-04 IT IT2601376A patent/IT1066935B/en active
- 1976-08-05 CH CH998176A patent/CH612016A5/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| FR2320571B1 (en) | 1978-12-01 |
| FR2320571A1 (en) | 1977-03-04 |
| IT1066935B (en) | 1985-03-12 |
| DE2633708A1 (en) | 1977-02-17 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PL | Patent ceased |