JPS646504Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a side printing device used to print a band-like mark for product identification on the edge of photographic film.

During the manufacturing process of photographic film, a band-shaped mark is printed on the edge (between the perforation and the edge) to indicate the type of film.
This printing is generally called side printing, and a side printing device is used to perform this side printing.

Various types of side printing devices have been proposed in the past. For example, in Japanese Utility Model Publication No. 16589/1989, a rotary encoder is provided to detect the running position of the photographic film, and a pulse signal output from this rotary encoder is used. A method is described in which a light emitting diode is momentarily emitted to print a mark at a predetermined position on the photographic film by counting and emitting light every time the photographic film is transported a predetermined distance. Further, in Japanese Utility Model Application Publication No. 56-38341, a pulse generator for detecting the transport speed of the photographic film is provided, and a pulse signal having a frequency proportional to the transport speed of the photographic film is generated from the pulse generator. A device is described in which the number of times the light source emits light is varied in accordance with the film running speed by amplifying and supplying the amplified light to the light source.

The former side print device is designed to operate by detecting the movement of the photographic film.
Even if the photographic film transport system stops driving, as long as the photographic film is traveling, printing can be performed at a predetermined position at a constant density. However, since this device is configured to print characters and the like at regular intervals, it is not possible to print continuous band-like marks at a constant density. The latter side printing device can print at a constant density when the photographic film is traveling at a certain speed or higher, but when the transport system is stopped, the inertia of the transport system causes the photographic film to print at a constant density. The light will be transferred slowly, and in this case, the frequency of the pulse signal will become extremely low, so the light emission time of the light source will become long, resulting in overexposure.

Furthermore, in order to print a continuous strip mark, it is necessary to turn on the light source continuously and control the brightness of the light source by detecting the film running speed, but it is necessary to control the brightness of the light source by detecting the film running speed. Therefore, it is very difficult to control the power of the power supply, and in the case of color film, there is a problem that the color tone of the mark changes due to a change in color temperature.

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks, it is an object of the present invention to provide a side printing device that can always print band-shaped marks at a constant density even when the film running speed becomes extremely slow. .

In this invention, a pulse signal output from a position detector is input to a timer circuit to generate a constant time signal regardless of the film running speed, and this time signal is used to make the light source emit light, and a mark plate that emits a slit light longer than the interval between the predetermined light emitting positions is placed in front of the light source to perform overlapping exposure. With this configuration, the light source emits light for a fixed time at fixed intervals on the photographic film to perform overlapping exposure, so the amount of exposure is constant regardless of the film running speed, and it is possible to print a band-shaped mark with a constant density. In particular, even if the photographic film running speed drops extremely, such as immediately after the transport system is turned off, the light source only emits light for a fixed time, so overexposure does not occur as in the past.

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

A strip-shaped photographic film 1 is transported in the direction shown by the arrow by a well-known transport system (not shown). The photographic film 1 is conveyed in close contact with the outer periphery of the print roller 2, causing the print roller 2 to rotate. A rotary encoder 3 is directly connected to the print roller 2, and outputs a pulse signal A every time the photographic film 1 is transported a certain length. This pulse signal A is input to a differentiating circuit 4, where it is differentiated. Signal B output from the differentiating circuit 4 is input to a timer circuit 5, and the rising edge of signal B triggers the timer circuit 5 to output signal C having a certain time width. This signal C is input to the light source drive circuit 6, where it is amplified. A light source 7 is connected to this light source drive circuit 6, and emits light for a period of time set by the timer circuit 5. The settings of the timer circuit 5 vary depending on the product type, and are set so that the concentration remains constant even if the product type changes. As the light source 7, a lamp, a light emitting diode, a flash discharge tube, a semiconductor laser, a CRT, etc. is used, and the mark plate 8 is illuminated. As shown in FIG. 3A, this mark plate 8 is formed with a slit 8a having a length l. This length l is determined so as to generate a slit light longer than the distance measured by the rotary encoder 3. Furthermore, as shown in Figure 3B,
It is also possible to use a structure in which two plates 9 and 10 are placed apart and a slit 11 is formed between them. The image of the slit 8a or 11 is formed on the edge portion of the photographic film 1 by an optical system 12.

FIG. 2 shows waveforms of the circuit shown in FIG. 1. Every time photographic film 1 is sent a certain distance,
The light source 7 emits light for a certain period of time, and the slit 8a or 11
The edge portion of the photographic film 1 is exposed to light passing through the photo film 1, and a continuous band-shaped mark is printed thereon. Here, since the length of the image of the slit 8a or 11 formed on the photographic film 1 is longer than the interval between the light emission from the light source 7, overlapping exposure is performed. This overlapping exposure means that no matter how fast or slow the photographic film 1 is, most parts of the photographic film 1 are exposed to light of a certain intensity for a certain period of time without passing through the slit 8a while the light source 7 is emitting light. It means to be done. This ensures that strip marks of constant density can be printed regardless of the film running speed.

The present invention having the above-mentioned configuration can print a band-shaped mark with a constant density no matter how the film running speed changes.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a timing chart thereof, and FIG. 3 is an explanatory diagram of a mark plate. 1... Photographic film, 3... Rotary encoder, 4... Differential circuit, 5... Timer circuit, 6... Light source drive circuit, 7... Light source, 8... Mark plate, 8a
...Slit, 9,10...Plate, 11...Slit.

Claims (1)

[Scope of utility model registration request] A side printing device that prints a band-shaped mark by irradiating light emitted from a light source onto a traveling photographic film, comprising: a position detector that outputs a pulse signal every time the photographic film is fed by a certain amount; and the pulse signal. a timer circuit that operates in synchronization with the timer circuit; a light source drive circuit that inputs the output signal of the timer circuit and causes the light source to emit light for a certain period of time; and a light source drive circuit that is arranged in front of the light source and detected by the position detector 1. A side print device comprising: a mark plate that generates a rectangular light spot that is longer than the distance of the side print device.