JP2525919Y2 - Auto focus mechanism for slide printer - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention is an auto-focus mechanism that automatically adjusts the focus of an image by adjusting the position of a slide film held between mounts in a slide printer with respect to photographic paper. About.

[Conventional technology]

In a slide printer that prints an image on a photographic paper from a positive slide film held by a mount, light from a light source is held by a slide mount held on a mount carrier through three complementary color filters of yellow Y, magenta M, and cyan C. Through the slide film
The transmitted light reaches the photographic paper via the lens unit.

[Problems to be solved by the invention]

In the conventional slide printer described above, the slide mounts are held at both ends by V guides having a V-shaped cross section, so that even if the slide films have different widths, the slide mounts of different thicknesses always keep the slide films on the same plane. To prevent the focus from shifting due to the difference in the thickness of the slide mount.

However, when the film is held by the slide mount, the film is often deflected by the influence of the film hold, and there is a disadvantage that the defocus occurs when the deflection occurs.

The present invention has been made in view of the above-described problems of the conventional slide printer, and has as its object to irradiate an infrared light source and an infrared light source to the slide film at an appropriate position below a mount carrier of the slide printer, and An autofocus mechanism that detects the shift of the film surface due to the deflection of the slide film by the photoconductive element that receives the infrared image reflected on the camera, moves the slide film to the appropriate position, and automatically adjusts the focus. To offer.

[Means for solving the problem]

Therefore, in the present invention, as a means for solving the above-mentioned problem, infrared rays are incident on an optical path which obliquely enters and reflects a slide film held by a slide mount held by a movable mount carrier of a slide printer. An infrared light source having a thin linear filament that emits light, a lens unit that collects the infrared light through a filter that passes only infrared light having a wavelength longer than the photosensitive wavelength of the photosensitive paper, and a filament image of the infrared light at the light receiving position And a pair of photoconductive elements provided in parallel, the position of the mount carrier is controlled by an output signal from the photoconductive element,
This embodiment employs a configuration of an autofocus mechanism for a slide printer in which the distance of a slide film from a printing lens unit on an exposure axis is adjusted.

[Action]

The autofocus mechanism configured as described above is provided at an appropriate position below the mount carrier of the slide printer so as not to hinder the operation of the optical sensor that detects image density information for normal printing.

Prior to the start of the printing operation, the focus shift due to the deflection of the slide film is adjusted as follows by the autofocus mechanism according to the present invention.

When an infrared light source irradiates the slide film from an infrared light source composed of a thin linear filament, an infrared image shown on the slide film is received on one of the two photoconductive elements by being biased toward one of the two. When a photoconductive element receives light, its resistance value changes.

Therefore, the change of the output signal corresponding to the change of the resistance value drives the drive section of the mount carrier via the electric control circuit to move the mount carrier up and down. When the mount carrier moves up and down, the slide film held by the mount carrier is adjusted in perspective with respect to the varifocal lens for printing, the slide film is set to the optimal position, and the printed image of the varifocal lens is cleared. Can be projected on photographic paper.

In the automatic focusing operation by the automatic focusing mechanism, if the filament image projected on the film surface appears on the photographic paper, the merchantability of the photograph is impaired. Photographic paper is generally sensitive up to 695 nm.

Therefore, it is preferable to combine the lens unit with an infrared transmission filter that transmits only infrared light of 715 nm or more.
It is preferable to select a photoconductive element having a spectral sensitivity of 715 nm or more.

Further, the light source for printing operation generally contains a heat ray absorbing filter glass, whose transmittance is 80% or more for light of 380 to 580 nm, 50% for 700 ± 15 nm, and 10% for light of 840 nm or more. % Or less. Therefore, even if the photoconductive element has a sensitivity of 715 nm or more, it may be affected by the strong light of the light source unit,
To prevent the influence, shutter or ND
(Neutral Density) filter and YMC cut filter should be used.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic diagram schematically showing a main part of a printing mechanism of a slide printer having an autofocus mechanism of this embodiment.

The printing mechanism converts the light from the light source 1 to ND (Neutral Densit
y) Transmitted light that has passed through a filter 3, a yellow Y, a magenta M, and a cyan C complementary color filter 4, and has passed through a slide film 8 held by a slide mount 7 held on a mount carrier 5 via a V guide 6. Is the magazine through the lens unit 9 and the shutter 2 in the open state.
The photographic paper X sent out by one frame from 10 is irradiated and printed.

The mount carrier 5 is provided to be vertically movable as described later. The lens unit 9 has a fixed focus or a variable focal length variable lens.

Below the mount carrier 5, the autofocus mechanism of this embodiment is provided as follows.

That is, as shown in FIG. 2, a lamp filament 11 which emits infrared rays on a light path oblique to the slide film 8 and has a thin linear filament, and an infrared transmitting filter which passes only infrared rays from the linear filament.
A light emitting lens 13 for condensing the infrared rays and irradiating the slide film 8 is provided.

A light-receiving lens that focuses infrared images on the light-receiving optical path
14, an infrared transmission filter 15 for passing only infrared light of the image, and a pair of photoconductive elements 16 for detecting infrared light of the linear filament.

As the infrared transmitting filters 12 and 15, an infrared photographing filter that transmits only infrared light having a wavelength of 715 nm or more is used.
The reason why the filters 12 and 15 are used in two stages is to prevent the light of the lamp filament 11 and the light source 1 for printing having a wavelength of 715 nm or less from being exposed to photographic paper.

The photoconductive element 16 is of a dual type in this embodiment, and is provided so that the electrode pattern is parallel to the infrared image of the linear filament as shown in FIG.

As the material of the photoconductive element, CdS, CdSe, PbS, PbTe,
There are various types such as InSb and Se. In this embodiment, CdSe having a high sensitivity and a spectral sensitivity of 715 nm or more is used.

The detection signal detected by the photoconductive element 16 is sent to the control circuit 17 as shown in FIG. 4, and controls the motor 19 via the drive circuit 18 to rotate forward and reverse.

The motor 19 is used for a drive unit 20 using a differential screw,
The drive section 20 moves the base 5 'of the mount carrier 5 up and down.

At an appropriate position below the mount carrier 5, in addition to the above-described autofocus mechanism of this embodiment, a photodiode for detecting image density information of three primary colors of blue B, green G, and red R to perform a printing operation. The average transmission density of slide film LATD (Larg
e Area Transmittance Density is measured, but is not shown because it is not directly related to the present invention.

In selecting the lamp filament 11 described above, the following points are noted.

As the above light source, it is ideal to use a point light source, and the accuracy is good if a small point image is projected on the film surface and controlled, but in the point light source, the CdSe photoconductive element operates stably. Because the light energy of the imaging is not obtained as much as
A lamp capable of obtaining a linear filament image is selected.

The smaller and shorter the size of the filament image shown on the photoconductive element is, the better. The reason for this is that the thinner the filament, the less the adverse effect of the pattern on the line of the filament image appears.

The autofocus mechanism of the embodiment having the above-described structure operates as follows.

First, the slide film 8 is set on the mount carrier 5 simultaneously with the normal printing operation. At an appropriate timing before and after the LATD photometry, the lamp filament 11 of the auto-focus mechanism is turned on to emit infrared rays of a linear filament image, and irradiates the slide film 8 via the infrared transmission filter 12 and the light emitting lens 13.

The infrared ray forms an image on the slide film 8 as shown in FIG. 2, passes through the light receiving lens 14 and the infrared ray transmitting film 15, and is received by the photoconductive element 16.

By the way, the position of the infrared image incident on the slide film 8 is shifted from the center of the film depending on the bending direction and the bending amount when the film surface is bent.

For example, if the film surface is bent upward and convex, the filament image is formed at point A, and if it is bent downward, the filament image is formed at point B. Therefore, the images at points A and B are formed on the photoconductive element 16 via the light receiving lens 14 as filament images at positions shifted from the reference point O 'by A' and B '.

When the image formed on the photoconductive element 16 is shifted from the reference point to any one of the reference points, the control circuit 17 shown in FIG. Is rotated in the reverse direction to stop when an image is formed on the point O '.

In this case, the photoconductive element 16 has a function of changing a resistance value when receiving light, and a dual type in which two light receiving elements are formed into one pack is used. The output signals of the respective elements are compared in the control circuit 17, and the control of the forward / reverse rotation is performed based on the sign of the difference signal, and the moving direction of the image point of the light emitting body is detected two-dimensionally.

When the motor 19 is driven by the control circuit 17 described above and the image formed on the photoconductive element 16 is displaced by A ', the motor 19 rotates forward and the drive unit 20 of the mount carrier 5 descends, and at the point A on the film surface. Move to the point O side. Therefore, the image moves to the point O 'on the photoconductive element 16, and the motor 19 stops.

When the film surface is deflected downward, the operations are all reversed, and the mount carrier 5 rises and the filament image formed at the point B moves to the point O and stops.

If the film surface is deflected as described above,
The defocusing of the image printed on the printing paper due to the deflection is automatically corrected, and a clear image is printed.

〔effect〕

As described in detail above, the autofocus mechanism according to the present invention includes an infrared light source, a lens unit, and a pair of photoconductive elements, and focuses by moving the position of the slide film up and down according to the output signal of the photoconductive element. Thus, even if the slide film is warped, there is an advantage that even when the slide film is deflected, the shift can be detected and the position of the slide film can be controlled in advance, so that a clear image can be printed on photographic paper.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a main part of a slide printer having a built-in auto-focus mechanism according to the present invention, FIG. 2 is a cross-sectional view of an embodiment of the auto-focus mechanism, and FIG. Schematic diagram represented in
FIG. 4 is a block diagram of a control circuit for driving the mount carrier. 1 ... light source, 2 ... shutter, 3 ... ND filter, 4 ...
... YMC filter, 5 ... Mount carrier, 6 ... V
Guide 7, Slide mount 8, Slide film 9, Vari-focal lens 10, Magazine
11 ... lamp filament, 12, 15 ... infrared transmission filter, 13 ... light emitting lens, 14 ... light receiving lens, 16 ... photoconductive element.

Claims (1)

(57) [Scope of request for utility model registration] 1. A thin linear filament which emits infrared light on an optical path for obliquely entering and forming an image on a slide film held by a slide mount held on a movable mount carrier of a slide printer. An infrared light source, a lens unit that focuses the infrared light through a filter that passes only infrared light having a wavelength longer than the photosensitive wavelength of the photosensitive paper, and a pair of photoconductive members provided at the light receiving position in parallel with the infrared filament image. For a slide printer, wherein the position of the mount carrier is controlled by an output signal from the photoconductive element, and the distance between the slide film and the printing lens unit on the exposure axis is adjusted. Auto focus mechanism.