JPH0580996B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photosensitive material detection device for detecting the presence or absence of a photosensitive material in a conveyance system of, for example, a photographic printing device.

[Conventional technology]

Conventional methods for detecting the presence or absence of a photosensitive material in a conveyance system include a method of detecting the presence of a photosensitive material by using a micro switch or the like and detecting the contact between the actuator and the photosensitive material, and a method of detecting by combining a light emitting element and a light receiving element. It was hot. Methods using microswitches require mechanical contact with the photosensitive material, so there is a risk of scratches or pressure fog on the photosensitive material, there are restrictions on the mounting position of the microswitch, and there are disadvantages such as low detection accuracy. It was hot.

A device for detecting the presence or absence of a photosensitive material by combining a light emitting element and a light receiving element is arranged as shown in FIG. 4, for example.

3 is a light-emitting element, 4 is a light-receiving element, 81 and 82 are photosensitive material conveying rollers, 83 is a processing section (for example, a photographing section or a developing section), 84 is a supply cassette, 85 is a suction cup, 86 is a guide path, and 87 is a supply roll. , 88 is a winding roll; the one shown in a is a device equipped with a transmission type detection section in the conveyance section of the sheet-like photosensitive material, and the one shown in b is equipped with a reflection type detection section in the conveyance section of the roll-like photosensitive material. It is equipped with a detection section.

In the device a, when there is no photosensitive material in the conveying section, the light emitted from the light emitting element 1 enters the light receiving element 2 and detects the absence of the photosensitive material, and when there is photosensitive material in the conveying section, the light is emitted by the photosensitive material. The light from the element 1 is blocked and does not enter the light receiving element 2, and it is determined that the photosensitive material is present.

In the device b, depending on the presence or absence of photosensitive material in the conveying section,
Since the amount of light reflected from the light emitting element 1 that is incident on the light receiving element 2 changes, the presence or absence of the photosensitive material can be detected.

[Problem that the invention seeks to solve]

The method using microswitches has drawbacks as described above.

For combinations of light-emitting elements and light-receiving elements, there is no problem if the sensitivity of the photosensitive material is used in a low range of light that does not pose a practical problem, but in reality, the emission wavelength of the light-emitting element and the light reception Elements with a photosensitive range of 650 to 1200 mm are easily available, and have high luminous efficiency and light-receiving sensitivity.Also, with the shift to color, many photosensitive materials have a slight sensitivity in the above wavelength range, and are not susceptible to strong light. cannot be used.

For this reason, the weakest possible light is used for detection, but this has the drawback of worsening the S/N ratio and causing malfunctions. Another method is to apply light to the back side of the photosensitive material (support side), but
It is not effective if the support is transparent or if the emulsion is coated on both sides of the support.

In addition, long-term exposure to even weak light can cause fogging on the photosensitive material, so if the photosensitive material stops during the transport path, it is necessary to take measures such as adding complicated control to stop light emission from the detection section.

An object of the present invention is to provide a detection device for eliminating the above-mentioned drawbacks.

[Means for solving problems]

The above object is to provide a conveying means driving motor for driving a conveying means for conveying a photosensitive material, a pulse wave generating means for generating a pulse wave at a frequency proportional to the rotational speed of the conveying means driving motor, and a pulse wave generating means for generating a pulse wave at a frequency proportional to the rotation speed of the conveying means driving motor. A photosensitive material comprising: a light-emitting element that emits light based on the light-emitting element; a light-receiving element that receives light from the light-emitting element; and a detection means that detects the presence or absence of the photosensitive material based on a signal generated from the light-receiving element. This is achieved by the detection device.

[Effect]

As mentioned above, the light emission of the light emitting element to detect the presence or absence of the photosensitive material is performed by pulse waves, so the pulse height (light intensity ) can be increased, and the detection sensitivity of the presence or absence of a photosensitive material can be increased.

In addition, since the pulse waves are extracted from the transport drive power source or the transport rotating body, the light emission can be automatically stopped when the transport system stops, so that the photosensitive material can be Exposure automatically stops when the camera stops, which prevents fogging caused by long exposure.

〔Example〕

FIG. 1 is a block diagram of the detection device of the present invention, in which 1 is an oscillating section and 2 is a light emitting element 3.
3 is a light emitting element, 4 is a light receiving element, 5 is an amplifier, 6 is a delay circuit, and 7 is a latch circuit. FIG. 2 shows an embodiment in which the oscillating section 1 shown in FIG. 1 is used as a driving motor of a conveyance means using a rotary encoder and a rotation detection circuit. M is a driving motor for the transport means, 11 is a light source (for example,
LED), 10 is the motor M and light source 11
12 is a disc for an encoder attached to the rotating shaft of the motor M; 1 is an ON/OFF switch;
3 is a light receiving element for the encoder, 14 is an amplifier, 2
1 is a Schmitt trigger circuit for waveform shaping, 3 is a light emitting element such as an LED for detecting a photosensitive material, and P
4 is a photosensitive material, 4 is a light receiving element for detection, 41 is an amplifier for a light receiving circuit, 61 is an amplifier for a delay circuit, 62
71 is a Schmitt trigger circuit for the delay circuit, and 71 is a D-type flip-flop circuit for latching the signal from the light receiving element 4.

With the above configuration, when the switch 10 for operating the conveying means is turned on, the light source 11 is turned on.
lights up and pulsed light is generated by the slit in the encoder disk 12. This pulsed light enters the light receiving element 13, is amplified by the amplifier 14, passes through the Schmitt trigger circuit 21, becomes a shaped pulse wave, lights up the light emitting element 3, and at the same time, part of its output is used for the delay circuit. It is input to amplifier 61.

The pulsed light emitted from the light-emitting element 3 is received or blocked by the light-receiving element 4 depending on the presence or absence of the photosensitive material P in the transport path (in the case of transmission type detection, it is blocked with the presence of photosensitive material and received without it. Reflection type detection In the case where there is a photosensitive material, the reflected light is incident on the light receiving element 4, and when there is no photosensitive material, there is no incident light.). A signal generated from the light receiving element 4 passes through an amplifier 41 and enters a D-type flip-flop circuit. On the other hand, the pulse wave input to the delay circuit amplifier 61 is subjected to an appropriate delay according to the response speed of the light receiving element 4 and the delay caused by the amplifier 41, and is made into a clock pulse by aligning the phase with the signal from the amplifier 41. The signal from amplifier 41 enters D-type flip-flop 71 and is latched to become a detection signal. The above waveforms are shown in FIG.

In the embodiments described above, the light for detecting the presence or absence of the photosensitive material is obtained by converting the optical signal from the encoder into an electrical signal, amplifying and shaping it, and lighting the light emitting element 3. However, the light from the encoder ( (pulsed waves) can be directly guided to the detection unit using a glass fiber or the like.

Further, when a pulse motor is used to drive the conveying means, the output from the driving power source is a pulse wave, and this pulse wave can be used. In any of the above cases, stopping the conveying means means stopping the oscillating section in FIG. 1, and the light emission for detecting the photosensitive material disappears.

Furthermore, the smaller the duty ratio of the pulse wave of the detection light, the less exposure to the photosensitive material, which is advantageous, and is determined by taking into account the response speed of the light emitting element 3 and the light receiving element 4, the frequency of the pulse wave, etc. but,
In general, it is easy to reduce the duty ratio to 10% or less.

〔Effect of the invention〕

As explained above, in the present invention, whenever the conveyance means is stopped, the light emission for detecting the photosensitive material is also stopped, and fogging due to long-term exposure does not occur.

In addition, since the light emitted for detecting the photosensitive material is a pulse wave, the peak value can be made sufficiently high while the exposure of the photosensitive material remains small, resulting in high detection sensitivity.
The detection device can be made resistant to external disturbances.

Since the device according to the present invention has the above-mentioned features, if this device is used in the conveyance section of photographic paper in a photographic printer, there will be no problem even if the photographic paper is left in the conveyance path for a long time. No hindrance. Also,
Because the process speeds of photo printers and developing machines are different,
When an accumulator or the like for temporarily storing photographic paper is installed between a printer and a developing machine, it is extremely effective to install a conveyance device having a detection device according to the present invention.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of the present invention, FIG. 2 is a diagram showing one embodiment thereof, FIG. 3 is a waveform explanatory diagram, and FIG. 4 is a diagram showing the main part of the prior art. . DESCRIPTION OF SYMBOLS 1... Oscillation part, 2... Driver circuit, 3... Light emitting element, 4... Light receiving element, 5... Amplifier, 6...
Delay circuit, 7...Latch circuit, 10...Switch, 11...Light source for encoder, 12...Encoder disc, M...Motor for driving the transport section, P...Photosensitive material.

Claims (1)

[Claims] 1. A conveying means driving motor that drives a conveying means for conveying a photosensitive material, a pulse wave generating means that generates a pulse wave at a frequency proportional to the rotational speed of the conveying means driving motor, and a pulse wave generating means that emits light based on the pulse wave. A photosensitive material detection device comprising: a light emitting element that receives light from the light emitting element; a light receiving element that receives light from the light emitting element; and a detection means that detects the presence or absence of the photosensitive material based on a signal generated from the light receiving element.