GB2025636A

GB2025636A - Instant picture camera

Info

Publication number: GB2025636A
Application number: GB7917037A
Authority: GB
Original assignee: Agfa Gevaert AG
Current assignee: Agfa Gevaert AG
Priority date: 1978-05-30
Filing date: 1979-05-16
Publication date: 1980-01-23
Also published as: FR2427632A1; DE2823651A1

Abstract

Exposed instant film is heated during development by means of a resistance heating element which may be situated inside both developer rollers 3 and 4 (as shown) or wound round the film path between the rollers and the exit aperture 9 (Figure 2). Battery 19 may be a Ni-Cd accumulator having sintered electrodes. Strain on the battery during development may be reduced by using stored energy, in the form of a motor-tensioned spring, for transport of the film. <IMAGE>

Description

SPECIFICATION Instant picture camera This invention relates to an instant picture camera having an arrangement for the development of photographic instant picture film assemblies, in which pockets of developer located in the instant picture film assemblies are squeezed out and the developer spread over the surface of the picture by means of rollers.

It is known that chemical processes in general, and photographic developing processes in particular, proceed more quickly at elevated temperatures.

Elevated temperatures are often used, therefore, when developing photographic coatings in the laboratory. It is also customary in the development of instant picture assemblies to heat the assemblies, which are provided with protective plates, by body warmth. Also, developing processes have been proposed in which heat is produced by chemical means to accelerate development. These processes have not been used in practice, however, as they impair what is in itself already a complicated de veloping process.

Especially in the case of the new generation of instant picture film assemblies, which are made in one piece, it generally takes a long time before the picture has finished developing and the layman is able to assess the result.

In accordance with the invention there is provided an instant picture camera having a pair of rollers for squeezing developer located in pockets in the instant picture film assemblies and spreading the developer over the surface of the picture, and an electrical heating device for heating the instant picture film assemblies.

Two types of instant picture cameras constructed in accordance with the invention will now be de scribed by way of example with reference to the accompanying drawings, in which: Figure 1 is a schematic sectional view of part of a first type of instant picture camera; and Figure 2 is a schematic sectional view of part of a second type of instant picture camera.

Referring to Figures 1 and 2 of the accompanying drawings, which show the parts of the instant picture cameras that are essential to the understanding of the invention, in each form of camera cassette 1 containing instant picture film assemblies 2 is situ ated in a housing 7,8, the assemblies being arranged to be exposed through an exposure window lain the cassette 1 and transported out of the cassette through a slot 1b in the front face. At the ends of the instant picture assemblies that are at the outlet side there are developer chambers 2a, the contents of which are, in use, squeezed out and spread over the surface of the print by two developer rollers 3 and 4.

In front of the outlet slot of the housing 7,8 there is a flap 9 for closing the outlet slot against light. After development, the particular film assembly that is uppermost is placed between the motor driven rollers 3 and 4 by a claw (not shown).

Referring now to Figure 1 of the drawings, in the first form of camera, inside each of the rollers 3 and 4 there is provided a heating wire or a heating coil 5 which can be connected to a battery 19 via a switch 17. The switch 18 is arranged to be closed when the camera shutter is released so as to enable preheating of the rollers to take place. It is also possible, however, to arrange that the period of preheating begins between the completion of operation of the shutter member and the commencement of operation of the claw.

The rollers have a smali but nonetheless significant heat capacity which determines the necessary preheating time and in the case of individual photographs that are not taken in quick succession leads to energy losses. For this reason, in the second form of camera, which is shown in Figure 2, the heating system, which comprises heating wires 15 and 16 (which can be supplied with current via a switch 18) is not arranged to heat the rollers 3 and 4, but is situated in front of the rollers (that is to say, between the rollers and the aperture covered by the flap 9, through which aperture the film leaves the camera).

The heating wires 15 and 16 are wound around the picture channel preferably in several coils. The coils can, as shown, be connected in series, or they can be connected in parallel.

Obviously, in both the first and the second form of camera, a great deal of strain is put on the battery of the camera if the heating is carried out when the transport motor is running. For this purpose Ni-Cd accumulators having sintered electrodes are advantageously used, because of their low internal resistance. Further, it can be advantageous to provide in the camera a means for storing mechanical potential energy, for example, a spring which can be tensioned by the motor when the heating device is not in use and which is arranged to drive the film transport.

Apart from reducing developing time, the camera according to the invention also makes it possible to achieve a more nearly constant developing temperature, which prevents or reduces colour fluctuations caused by temperature changes. In order to ensure especially consistent developing conditions it is advantageous to use a control device that regulates the rate of heating in accordance with the outside temperature in such a manner that development tends always to take place at a constant temperature.

It has been shown that maintaining the picture at a temperature of about 20"C (which can be achieved by connection and radiation from the heating elements) is advantageous and approximately halves the developing time. It is pointed out, though, that the instant picture film assemblies on the market at present should not be heated in that way, since, if they were to be, the colours in the picture would be too intense. The emulsion must therefore be one that is suitable for deveopment at a higher temperature.

1. An instant picture camera having a pair of rollers for squeezing developer located in pockets in the instant picture film assemblies and spreading the developer over the surface of the picture, and an

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Instant picture camera This invention relates to an instant picture camera having an arrangement for the development of photographic instant picture film assemblies, in which pockets of developer located in the instant picture film assemblies are squeezed out and the developer spread over the surface of the picture by means of rollers. It is known that chemical processes in general, and photographic developing processes in particular, proceed more quickly at elevated temperatures. Elevated temperatures are often used, therefore, when developing photographic coatings in the laboratory. It is also customary in the development of instant picture assemblies to heat the assemblies, which are provided with protective plates, by body warmth. Also, developing processes have been proposed in which heat is produced by chemical means to accelerate development. These processes have not been used in practice, however, as they impair what is in itself already a complicated de veloping process. Especially in the case of the new generation of instant picture film assemblies, which are made in one piece, it generally takes a long time before the picture has finished developing and the layman is able to assess the result. In accordance with the invention there is provided an instant picture camera having a pair of rollers for squeezing developer located in pockets in the instant picture film assemblies and spreading the developer over the surface of the picture, and an electrical heating device for heating the instant picture film assemblies. Two types of instant picture cameras constructed in accordance with the invention will now be de scribed by way of example with reference to the accompanying drawings, in which: Figure 1 is a schematic sectional view of part of a first type of instant picture camera; and Figure 2 is a schematic sectional view of part of a second type of instant picture camera. Referring to Figures 1 and 2 of the accompanying drawings, which show the parts of the instant picture cameras that are essential to the understanding of the invention, in each form of camera cassette 1 containing instant picture film assemblies 2 is situ ated in a housing 7,8, the assemblies being arranged to be exposed through an exposure window lain the cassette 1 and transported out of the cassette through a slot 1b in the front face. At the ends of the instant picture assemblies that are at the outlet side there are developer chambers 2a, the contents of which are, in use, squeezed out and spread over the surface of the print by two developer rollers 3 and 4. In front of the outlet slot of the housing 7,8 there is a flap 9 for closing the outlet slot against light. After development, the particular film assembly that is uppermost is placed between the motor driven rollers 3 and 4 by a claw (not shown). Referring now to Figure 1 of the drawings, in the first form of camera, inside each of the rollers 3 and 4 there is provided a heating wire or a heating coil 5 which can be connected to a battery 19 via a switch 17. The switch 18 is arranged to be closed when the camera shutter is released so as to enable preheating of the rollers to take place. It is also possible, however, to arrange that the period of preheating begins between the completion of operation of the shutter member and the commencement of operation of the claw. The rollers have a smali but nonetheless significant heat capacity which determines the necessary preheating time and in the case of individual photographs that are not taken in quick succession leads to energy losses. For this reason, in the second form of camera, which is shown in Figure 2, the heating system, which comprises heating wires 15 and 16 (which can be supplied with current via a switch 18) is not arranged to heat the rollers 3 and 4, but is situated in front of the rollers (that is to say, between the rollers and the aperture covered by the flap 9, through which aperture the film leaves the camera). The heating wires 15 and 16 are wound around the picture channel preferably in several coils. The coils can, as shown, be connected in series, or they can be connected in parallel. Obviously, in both the first and the second form of camera, a great deal of strain is put on the battery of the camera if the heating is carried out when the transport motor is running. For this purpose Ni-Cd accumulators having sintered electrodes are advantageously used, because of their low internal resistance. Further, it can be advantageous to provide in the camera a means for storing mechanical potential energy, for example, a spring which can be tensioned by the motor when the heating device is not in use and which is arranged to drive the film transport. Apart from reducing developing time, the camera according to the invention also makes it possible to achieve a more nearly constant developing temperature, which prevents or reduces colour fluctuations caused by temperature changes. In order to ensure especially consistent developing conditions it is advantageous to use a control device that regulates the rate of heating in accordance with the outside temperature in such a manner that development tends always to take place at a constant temperature. It has been shown that maintaining the picture at a temperature of about 20"C (which can be achieved by connection and radiation from the heating elements) is advantageous and approximately halves the developing time. It is pointed out, though, that the instant picture film assemblies on the market at present should not be heated in that way, since, if they were to be, the colours in the picture would be too intense. The emulsion must therefore be one that is suitable for deveopment at a higher temperature. CLAIMS

1. An instant picture camera having a pair of rollers for squeezing developer located in pockets in the instant picture film assemblies and spreading the developer over the surface of the picture, and an electrical heating device for heating the instant picture film assemblies.

2. An instant picture camera as claimed in claim 1, wherein the rollers are provided with built-in heating elements.

3. An instant picture camera as claimed in claim 1, wherein the heating device is arranged between the rollers and an aperture arranged to allow the film assembly to leave the camera by passing through it.

4. An instant picture camera as claimed in claim 1, which includes a controi device for so controlling the temperature of the heating device in accordance with the outside temperature that the film assemblies tend to be developed at a constant temperature irrespective of the outside temperature.

5. An instant picture camera as claimed in any one of claims 1 to 4, which comprises an electric motor, and means for releasably storing mechanical energy generated by the motor and, when suitably activated, for causing the rollers to rotate, wherein the arrangement is such that, in use, the motor generates mechanical energy only in a period when the heating device is not heating an instant picture assembly.

6. An input picture camera substantially as hereinbefore described with reference to, and as shown in, Figure 1 or Figure 2 of the accompanying drawings.