JPH0427932A - Film imaging system - Google Patents

Abstract

PURPOSE:To prevent blur of an output picture due to deformation of a film negative caused by the heat of a light source by preliminarily curving and deforming the film negative up to a maximum degree of thermal deformation by heating and making the light from the light source pass through the film negative and projecting the transmitted light to the surface of a photosensitive recording medium through an optical system to record the picture on this surface. CONSTITUTION:A preheat box 35 is provided between a film magazine 37 to which a film negative 32 is loaded and a film holder 33, and the same preheating light source 36 as a light source 30 and a condenser lens 39 are provided in the preheat box 35. The film negative 32 sent from the film magazine 37 to the preheat box 35 is preheated by the preheating light source 36 and is kept in the stable state where thermal deformation is saturated. Thereafter, the transmitted light is projected to the surface of a photosensitive pressure-sensitive recording medium to record the picture on this surface by a film projector 3, and therefore, the film negative 32 is not deformed during exposure and the output picture is not blurred.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a film printing system.

[Prior art] Conventionally, light from a light source is transmitted through this film original screen,
The transmitted light is projected onto the surface of a photosensitive recording medium through an optical system,
In film printers that use a film printing method that records images on the surface of a photosensitive recording medium, as a countermeasure against changes in the shape of the original film during exposure due to heat, etc., the film original is cooled. Some models are designed to minimize changes in the shape of the film, and are equipped with an autofocus function that corrects changes in focal length due to changes in shape by moving the projection lens. Methods such as using a curved field lens, which was designed based on the assumption that the shape would be a constant shape (generally a part of a spherical surface expressed with a constant curvature), were adopted.

[Problems to be Solved by the Invention] However, the method of minimizing the shape change by cooling the original film has a limit on the cooling temperature and increases the cost. In addition, the autofocus function that copes with changes in focal length due to changes in shape, when the projection time is a certain length,
Even if the lens and film surface can be corrected to a constant degree in response to deformation, a device that constantly maintains a constant magnification by correcting the distance to the projection plane, which has a large magnification, would be expensive (
Also, it is rare for the entire film surface to deform uniformly in the optical axis direction, so this is not very meaningful.)
Since it is not practical, it is not actually used, and the image magnification changes due to the autofocus operation, and the image projected within the projection time becomes blurred due to the change in magnification.

If the shape changes rapidly, it is impossible to respond instantly, and there is a possibility that the image formation on the exposure surface will shift during autofocus. Furthermore, the autofocus mechanism uses two photocells to receive light emitted from one point on the original film, detect errors, and correct the projection lens to the correct position. Since the film and projection lens positions are corrected by only position detection, correction is not effective for deformations other than the predetermined area to be detected.

In addition, the method of using a curved field lens, which is designed in anticipation of the deformation of the film original, is based on the film original.
Depending on the mount used (paper, plastic, glass, etc.), the film original may not always deform as expected and the image may not be corrected in the focal plane.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a low-cost film printing method that can cope with the continuous deformation of the film original due to the heat of the light source and that does not blur the output image. The purpose is

[Means for Solving the Problems] In order to achieve this object, in the film printing method of the present invention, the original film is previously heated to be curved and deformed to approximately the maximum degree of thermal deformation, and then exposed to light from a light source. is transmitted through this film original screen, and the transmitted light is projected onto the surface of a photosensitive recording medium through an optical system, thereby recording an image on the surface of the photosensitive recording medium.

[Embodiments] Hereinafter, embodiments embodying the present invention will be described with reference to the drawings.

First, a first example will be described. FIG. 6 is a schematic diagram of a film mount to which the film printing method of the present invention is applied.

The photosensitive and pressure sensitive recording medium 10 that has come out of the photosensitive and pressure sensitive recording medium cassette 1 is sent to an exposure surface 2 and exposed by a film projector 3. After the exposure, the photosensitive and pressure sensitive recording medium 10 is superimposed on the developer paper 40 fed from the developer paper cassette 4, and sent to the pressure development unit 5, where it is subjected to pressure development.

Thereafter, the photosensitive and pressure sensitive recording medium 10 is wound up by a winding roller 11, and the color developer paper 40 is conveyed to a thermal fixing unit 6, where it is thermally fixed, and then discharged onto a paper discharge tray 7.

Next, the film projector 3 will be explained in detail using FIG.

A halogen lamp 30 as a light source is provided inside the case 20, and a reflecting mirror 21 is placed on the optical axis of the halogen lamp 30.
, two condensing lenses 23, and a film holder 33.
A projection lens 38 is provided respectively. Further, one end of the case 20 is open, and a shutter 34 is provided in the opening, and the shutter 34 faces the exposure surface 2.

A heat shielding filter 24 is inserted between the two condensing lenses 23, and a film original 32 is held inside the film holder 33 by a film mount 31.

Deformation due to heat, which is one of the causes of deformation of film originals, will now be explained.

As shown in FIG. 5, the original film 32 is constructed by pasting together a hess film 32a and a photosensitive coloring layer 32b (sensitive material layer), so the line between both the hess film 32a and the photosensitive coloring layer 32b is Due to the difference in expansion coefficients, a certain degree of warping occurs depending on the environmental temperature. In addition, since the film is thick, when light is applied from one side of the film, the heat rays contained in the film raise the temperature of one side of the film, creating a bimetallic effect and causing warping. This is because the temperature gradient changes over time due to heat conduction within the film, so the amount of distortion changes, or the temperature gradient on both sides of the film changes due to the amount of heat from the light source and the environmental temperature.After a certain period of time, the temperature gradient becomes stable. The shape becomes distorted according to the temperature gradient.

Next, the operation of the film projector 3 during exposure will be explained.

First, with the shutter 34 closed, the halogen lamp 30 is turned on to saturate the deformation of the original film 32 with heat from the 10-gen lamp 30 (for about 10 seconds) to stabilize the deformed shape, and then open the shutter 34. Start exposure. As shown in FIG. 2, light from a halogen lamp 30 is reflected by a reflecting mirror 21, condensed by a condensing lens 23, and transmitted through an original film 32, and this transmitted light is passed through a projection lens 38.
The image is enlarged by , and an image is formed on the exposure surface 2 .

Thereafter, image formation is performed as described above.

Here, the projection lens 38 used in this embodiment will be explained in detail using FIG. 4.

Let T be the amount of deformation at the center of the film original image 32, and let t be the shift of the focal plane at the center of the image with respect to the exposure plane 2. For example, if the aperture value F of the projection lens 38 of this embodiment is 5.6, the magnification M is 8 times, and the center deformation fiT of the film original image 32 is 0.9 mm, then t=TXM==0.9X8=
The depth of focus Δ of a 7.2 mm projection lens can be expressed by the following equation, where ε is the diameter of the circle of least confusion (allowable blur), and M is the aperture value F1 magnification.

Δ=εxFx (1+M) Therefore, the depth of focus Δ in this example is 8/30 mm, which is 8 times the diameter ε of the circle of least confusion, which is generally 1730 mm for 35 mm film, and Δ=8/30.
x5.6x (1+8)=13.44 m, so t is within the depth of focus and the blur of the image is within the allowable range.

Next, a second embodiment of the present invention will be described using FIG. 3. In the second embodiment, the same parts as in the first embodiment are given the same reference numerals, and detailed explanation thereof will be omitted.

As shown in FIG. 3, a preheat box 35 is provided between the film magazine 37 loaded with the original film 32 and the film holder 33, and inside the preheat box 35 there is a preheating light source 3 that is the same as the light source 30.
6 and a condenser lens 39 are provided.

The original film 32 sent from the film magazine 37 to the preheat box 35 is preheated by the preheat light source 36, kept in a stable state where thermal deformation is saturated, and exposed immediately after being sent from the preheat box 35 to the film holder 33. It is possible to do it.

As is clear from the above detailed description, in the film printer using the film printing method of the present invention, the original film 32 is heated to be curved and deformed in advance to approximately the maximum degree of thermal deformation, and then the light source 30 The film original image 32 is transmitted through the film original screen during exposure, and the transmitted light is projected onto the light-sensitive pressure-sensitive recording medium surface through the projection lens 38 to record an image on the photosensitive recording medium surface. There is no deformation and the output image is not blurred.

Note that the present invention is not limited to the embodiments described above, and changes can be made without departing from the spirit thereof.

[Effects of the Invention] As is clear from the above detailed description, in the film printing method of the present invention, the original film is heated to curve and deform in advance to approximately the maximum degree of thermal deformation, and then the light from the light source is The transmitted light is transmitted through the film original screen, and the transmitted light is projected onto the photosensitive recording medium surface through an optical system, and an image is recorded on the photosensitive recording medium surface, so the film original image is not deformed during exposure and the output image is Not blurry.

[Brief explanation of drawings]

1 to 6 show embodiments embodying the present invention. FIG. 1 is a configuration diagram of a film projector, FIG. 2 is a side view of the film projector during exposure, and FIG. 3 is a preheating A top view when using a box, Figure 4 is an explanatory diagram showing changes in the focal plane due to deformation of the original film,
FIG. 5 is a sectional view of the original film, and FIG. 6 is a schematic diagram of the structure of the film printer. In the figure, 10 is a photosensitive pressure sensitive recording medium, 23 is a condensing lens, 3
0 is a halogen lamp, 32 is a film original, 35 is a preheat box, and 38 is a projection lens. @1 figure 112 figure! Figure 6 U Figure S

Claims (1)

[Claims] 1. The original film is heated in advance to curve and deform it to approximately the maximum degree of thermal deformation, then the light from the light source is transmitted through the original film, and the transmitted light is projected onto the surface of the photosensitive recording medium via the optical system. A film printing method characterized in that an image is recorded on the surface of this photosensitive recording medium.