JPH01191127A - Correcting method for focusing position of photograph enlarger - Google Patents

Abstract

PURPOSE:To improve focusing accuracy by dividing supporting shafts for moving into plural parts, respectively, based on a calculated specific length and correcting a focusing position according to an error of each divided part. CONSTITUTION:The device is a photograph enlarger which relatively moves the position of an original image film 36, that of a lens 40 and that of a photosensitive material along a screw, and which forms an image on the photosensitive material with light transmitting the original image film. Here, the supporting shafts 12 and 14 for moving are divided into plural parts based on a calculated specific length, which is predetermined. The divided lengths are actually measured, and the error between the actually measured value of each divided part and the calculated length is obtained. According to the error of each divided range, a focusing position is corrected. Thus, the accuracy of a focusing position can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a photographic enlarger in which the relative positions of an original film, a lens, and a photosensitive material are moved and an image is formed on a photosensitive material at a predetermined magnification by transmitted light that has passed through the original film. The present invention relates to a method for correcting the focus position of a machine.

[Prior art]

Conventionally, when printing a photograph onto a photosensitive material, an enlarger is used to determine the magnification of the image to be printed on the photosensitive material relative to the image on the original film such as negative film, and based on this magnification, the head of the enlarger is moved to the surface where the enlarger is installed. Exposure is performed after the lens is moved vertically relative to the camera.

Such enlargers include a type (so-called inverted type) in which a light source is placed in the main body of the device, and a light beam is irradiated from below the negative film to expose the photosensitive material through a lens provided in the head. A light source and a lens are installed in the head, a negative film is interposed between the light source and the lens, a light beam is irradiated from above the negative film, and the transmitted light is transmitted through the lens onto the table of the main body of the device. There is a type (so-called royal type) that exposes the placed photosensitive material by irradiating it with light. Negative film is usually loaded into a negative carrier and attached to the enlarger, and when exposure with one negative film is completed, the operator removes the negative carrier from the enlarger.
It is designed to be replaced with the next negative film and then reloaded.

By the way, in such a photographic enlarger, when the enlargement magnification is changed, the head is moved in the optical axis direction (vertical direction with respect to the device installation surface). The lens is also moved vertically for focus adjustment. A ball screw is used in the vertical drive mechanism for such movement. This ball screw drive has a male screw (on the spindle side installed parallel to the direction of movement) and a female screw (
The rotating shaft of the pulse motor can be adjusted by sending a predetermined pulse signal to this pulse motor. The driving force is transmitted to the support shaft, and the support shaft is rotated.

However, even with such a highly accurate ball screw, there is a slight error (axial pitch error), and the error increases as the overall length increases. For this reason, in the past, the error in the overall length of the male screw was actually measured and the number of pulses supplied to the pulse motor was always uniformly corrected.

In other words, assuming that the total length of the male screw of the spindle is 1000 mm and the actual measurement value of the error is 1 mm, when calculating the number of pulses when moving 5 mm, the moving distance is (5 mm + (I
0) ). In this way, errors can be corrected.

[Problem that the invention seeks to solve]

However, the above-mentioned error does not occur evenly over the entire length of the male thread, and even if the error is 1 mm overall, there may be an error of 0.2 mm in some parts, and no error in other parts. Therefore, evenly correcting the errors may result in some areas where the accuracy decreases.

Therefore, with such error correction, the focus position may become inappropriate.

In consideration of the above-mentioned facts, the present invention aims to provide a focus position correction method for a photographic enlarger that can improve focus accuracy when changing the relative positions of an original film, a lens, and a photosensitive material.

[Means for solving problems]

The focus position correction method for a photo enlarger according to the present invention includes:
A focus position correction method for a photographic enlarger in which the relative positions of an original film, a lens, and a photosensitive material are moved along a screw, and an image is formed on the photosensitive material at a predetermined magnification by transmitted light transmitted through the original film, the method comprising: Divide the spindle into multiple parts based on predetermined calculated lengths, measure the divided lengths, and compare the measured length and calculated length for each divided range. The focus position is corrected based on the error for each divided range.

[Effect]

In the present invention, the total screw length is divided into multiple parts based on a predetermined calculated length (calculated value), the divided lengths are actually measured (actual value), and the error between this measured value and the calculated value is calculated. This is determined in advance for each divided range, and when the relative positions of the original film, lens, and photosensitive material are changed, the errors are corrected for each divided range, which improves the accuracy of the focus position. .

Note that the screw may be divided approximately equally, or the standard magnification portion may be finely divided, and the less frequently used portions such as high magnification and low magnification may be coarsely divided.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A photographic enlarger to which the present invention is applicable will be described in detail below with reference to the drawings. As shown in FIG. 1, the so-called upright type photo enlarger main body 10 has two parts in its support (not shown).
Book support shafts 12 and 14 are erected parallel to each other, and a printing magnification adjustment head section 16 and a focus adjustment section 18 are screwed into male threads formed on these support shafts 12 and 14, respectively. . The rotation shafts (not shown) of pulse motors 20.22 are coaxially fixed to the bases of the support shafts 12.140, respectively, and the support shafts 12.14 are rotated by the iK driving force of the pulse motors 20.22. It has become. Here, by rotating each of the support shafts 12 and 14, the head section 16 or the focus adjustment section 18 can be independently connected to the support shafts 12 and 14.
．． 14 in the axial direction.

The support shafts 12 and 14 are installed in the photo enlarger main body 10 in a single state as shown in FIG. 2, with the error in the pitch A in the axial direction corrected.

This pitch error is corrected for each calculated predetermined number of threads Bl, B21B31...Bn when the entire length of the male screw is equally divided, and is
It is stored in M. That is, the RAM stores the actual length of each predetermined number of threads B+, B2, B3,..., Bn, and stores the calculated value (Bn XA) based on the measured value and the calculated number of threads. Error d I , a, ,
a, , “ ” , dn are determined and stored separately.

That is, for example, within the range of the predetermined number of threads B2, the distance L''
When moving B2', the correction value B2' is calculated using the following formula.

Here, d2: Error L° at the predetermined number of screw threads B2: Movement distance A: Pitch (=movement distance for one rotation of the support shaft).

Here, by multiplying the number of pulses of the motor to rotate the support shaft once, the number of pulses to move the moving distance L' can be easily obtained.

The head section 16 is composed of a lamp house section 24 and a negative carrier loading section 26, and a halogen lamp 28 and a dimming filter 30 are arranged in this order within the lamp house section 24. This dimmer filter 30 is composed of yellow (Y), magenta (M), and cyan (C) filters, and these filters are each independently moved in a direction perpendicular to the optical axis by the driving force of a driving section 32. It is arranged so that it can be moved. A negative carrier 34 is loaded in the negative carrier loading section 26, and a negative film 36 is held in the negative carrier 34.

The head section 16 and the focus adjustment section 18 are connected by a bellows 38, so that the inside of the head section 16 and the inside of the focus adjustment section 18 are in communication with each other and are shielded from light from the outside, and the two can be approached and separated. An enlarger lens 40 is attached to the lower end of the focus adjustment section 18 in FIG. halogen lamp 2
8, the light beam reaches the table 4 of the enlarger main body 10 via the light control filter 30, the negative film 36, and the enlarger lens 40.
The image is formed on a photographic paper arrangement section 44 on the photographic paper 360, and the projected image of the negative film 360 can be visually viewed by a worker seated on a chair 46.

Further, an operation panel 50 is provided on the table 42 of the enlarger main body 10.
is provided, and is configured such that measurement data can be input, setting magnifications can be set, and trimming can be performed from this operation panel 50.

Further, when the photographic paper 52 is placed in the placement section 44 of the table 42, an image of the negative film 36 is formed on the photographic paper 52 when the halogen lamp 28 is turned on.

The operation panel 50 is connected to a microcomputer 54 including RAM, ROM, and CPU. Further, the microcomputer 54 has images of the pulse motors 20 and 22 and the drive unit 32, and outputs drive signals based on instructions from the operation panel 50.

The operation of this embodiment will be explained below.

First, a procedure for measuring errors in the male threads of the support shafts 12 and 14 will be described.

First, with the spindle 12.14 as a single unit, divide the entire length of its male thread into equal parts to determine the predetermined number of threads B, and for example, from the top of Figure 2, sequentially B+ SB2, B3, ...Bn. , measure each dimension.

The actually measured number of screw threads B+, B2, B3,...
・Each error d1, d2, d3, ... dn of Bn
seek. The obtained errors d+, d2, d3,...
dn is the number of screw threads B I %B2 , B3 ,
...is stored in the RAM of the microcomputer 54 together with Bn.

Thereafter, by attaching the spindle 12.14 to the photo enlarger main body 10, the attached spindle 12.14 corresponds to the error stored in the microcomputer 54.

Next, the support shaft 12 is transferred to the photo enlarger applied to this embodiment.
．． 14 will be explained with reference to the flowchart in FIG.

First, in step 100, when the negative carrier 34 is loaded into the negative carrier loading section 26 (this detection may be performed by operating a predetermined key on the operation panel 50 after loading the negative carrier, or It is also possible to provide a limit switch or the like and make the determination based on the signal from this limit switch.) Then, the process moves to step 102 and the position of the negative film 36 is confirmed. This can be easily confirmed by the operator since a negative image is formed on the placement section 44 by lighting the halogen lamp 28 without placing the photographic paper 52 on the placement section 44.

Once the position of the negative film 36 is confirmed, step 10
4, the magnification is set by operating the keys on the operation panel 50, and then, in step 106, the number of sheets to be printed is set. When these settings are completed, the photographic paper 52 is placed in the placement section 44, and the process moves to step 108, where the pulse motor 20 is driven based on the set magnification and the head starts moving, and the pulse motor 22 is also driven. Driven head part 1
At the same time as 6, the focus adjustment section 18 is also moved. The pulse motors 20 and 22 are driven according to the number of pulses supplied from the microcomputer 54. At this time,
Based on the continuously changing magnification, the microcomputer 54 calculates the optimum focus at that time, corrects the drive signal to the pulse motor 22, and moves the object always in focus.

Here, as shown in FIG. 4, the microcomputer determines which of the predetermined pitches the movement range of the head portion 16 falls within based on the set magnification (step 150), for example, within a predetermined thread pitch. If it is determined that it is within the range of Equation 82, the error d2 corresponding to this B2 is set as RA.
Read from M (step 152). In step 154, based on this read value, a correction value B2'' is determined using the equation (1), and this correction value B2.° is multiplied by the number of pulses required to rotate the spindle once, and the The pulse motor 20.22 is driven based on the determined number of pulses (step 156).If the movement range of the head section 16 spans a plurality of predetermined pitches, each error dn is added.

Since the entire length of the male screw is divided in this way and errors are corrected for each divided length, focus accuracy is improved.

In the next step 109, exposure processing is performed, and the image on the negative film 26 is formed onto the photographic paper 52. When the exposure control is completed, the process moves to step 110, and it is determined whether or not the set predetermined number of sheets has been reached. If the number has not been reached, the process moves to step 109, where exposure processing is continued. If the predetermined number of sheets has been reached, the process moves to step 114, where it is continuously determined whether the exposure process has ended.

If a negative determination is made in step 114, it is determined that exposure control with different magnification settings is to be performed on the same image, and the process proceeds to step 102 to repeat the above-described processing. If the determination is affirmative, it is determined that the exposure process has ended, and this routine ends.

In this example, the entire length of the male screw is divided equally, but the frequently used standard magnification portion may be divided finely, and the rarely used portions such as high magnification and low magnification may be coarsely divided.

〔Effect of the invention〕

As described above, the method for correcting the focus position of a photographic enlarger according to the present invention has the excellent effect of improving focus accuracy when changing the relative positions of the original film, the lens, and the photosensitive material.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a photo enlarger to which the present invention can be applied;
The figure is an enlarged view of the spindle, FIG. 3 is a flowchart showing the exposure control routine of this embodiment, and FIG. 4 is a flowchart showing movement control to the set magnification position. DESCRIPTION OF SYMBOLS 10... Enlarger main body, 16... Head part, 18... Focus adjustment part, 36... Negative film, 54... Microcomputer.

Claims (1)

[Claims] (1) A focus position correction method for a photographic enlarger in which the relative positions of an original film, a lens, and a photosensitive material are moved along a screw, and an image is formed on the photosensitive material at a predetermined magnification by transmitted light that has passed through the original film, the method comprising: The support shaft for movement is divided into a plurality of parts based on predetermined calculated lengths, the divided lengths are actually measured, and the measured length and the calculation for each divided range are calculated. A focus position correction method for a photographic enlarger, characterized in that the error with respect to the above length is determined, and the focus position is corrected based on the error for each divided range.