Research and Development

The technical challenge in significantly reducing thermal capacity is to stabilize the temperature when developing the film. Specifically, for a large machine in which high processing ability is required, the amount of heat transfer per unit time during the development process becomes large, which makes it difficult to stabilize the temperature of the heat development unit. In the heat development drum method (Fig.1) employed by conventional models, a film is closely bonded to a rotating large-diameter heat drum, then heated and conveyed. Therefore, throughout the development process, from the rise of film temperature to the completion of development, a constant amount of heat is applied to the film. On the other hand, in the divisional heating plate method, the heating process is divided into process units (preheating, temperature rise, development) according to the direction of conveyance so that each process unit can be independently regulated (Fig.2). A significant feature is to optimize the amount of heat according to the characteristics necessary for each process unit. That is, adjustments can be made so that a large amount of heat is provided for the process which requires great heat, and a small amount of heat is provided for the process which requires less heat.
This adjustment has greatly reduced energy loss which has resulted in the contribution to the reduction of power consumed by the entire piece of equipment.

First of all, prior to starting the designing of the heat development process, we made a simulation and verified it by using a prototype machine to observe the effect of temperature changes in each section on the density. As a result, the clear findings are: [1] when temperature is less than 100C (preheating section), density is not so affected;
[2] during the temperature from 100C to the development temperature (temperature rise section) density is greatly affected; and [3] when temperature is near the development temperature (slit heating section), density does not have much dependence on the temperature. Based on the results, we determined the thermal capacity of each section so that the "degree of influence on the density × thermal load during film processing / thermal capacity" becomes equal to that of conventional models. FIG.3 shows the amount of density change depending on the temperature as stated above [1] to [3].

With regard to the processes (preheating section and slit heating section) in which temperature changes do not significantly affect density, reduction of thermal capacity has become possible and total thermal capacity per print has been successfully reduced by about 50% of that of conventional models. Fig.4 shows the comparison concept of the thermal capacity per print.
The area of the shaded portion located on the left in the drawing shows the thermal capacity during the development process by using a heat drum method. On the other hand, the area of the dotted portion located on the right in the drawing shows the thermal capacity during the development process by using a divisional heating plate method. The comparison of the area of the right and left portions in Fig.4 indicates that in the divisional heating plate method, when compared to the heat development drum method, necessary energy can be applied when required, therefore, required total energy can be small.

When compared with conventional models, electric power that is assumed to be consumed in general hospitals (8 hour operation, 100 printing) has been successfully reduced by 36% (mean value) which is greater than the 30% target that Konica Minolta had aimed for when comparing to conventional models.
It is considered that this was accomplished by the effect of power reduction at the start-up of the machine due to the thermal capacity reduction measures as well as the effect of total thermal capacity reduction during printing. (Fig.5)