In MFPs, heat must be applied when fixing toner on paper. Notably, power consumption of the fixing unit accounts for more than sixty percent of an MFP’s overall power consumption. In order to cut power consumption in the fixing process, Konica Minolta has worked on energy conservation of the fixing unit, as exemplified by its IH Fixing technology as well as on research and development of a toner that can be fixed at a lower temperature. Konica Minolta has successfully lowered the fixing temperature over the past three generations of toner, and remains committed to further lowering the fixing temperature of the latest generation of toner being developed.
When printing on thick paper such as business cards, it takes time to transmit the heat of the fixing unit to the overall surface of the paper, resulting in reduced printing speed. Toner that can be fixed at a low temperature eliminates the need to excessively raise the temperature of the paper surface and helps increase printing speed.
Commercial digital printers (printing speed: approx. 60–70 ppm) are expected to ensure high-speed printing even on thick paper without sacrificing efficiency. This requirement can be met by developing a toner that can be fixed at a lower temperature.
The fixing temperature can be lowered if toner melts at a low temperature. However, trouble would occur if toner melted easily in a high-temperature environment in MFPs or during transportation in hot weather etc. Toner needs to melt easily in the fixing unit; but be difficult to melt in other environments.
Konica Minolta achieved this goal by blending different types of resin to produce toner particles. Specifically, the surface of the particles consists of hard-to-melt resin, while the core comprises easy-to-melt resin. The wax for preventing adhesion on the roller in the transfer process is designed to melt at a low temperature and to seep from inside toner particles faster than before. These improvements facilitate separation from the fixing unit at a low temperature. The fixing temperature has been successfully lowered by about 25°C from that of conventional models.
The significantly increased color pigment content in a single toner particle helps minimize glare and reflection attributed to resin and wax in the dark-colored areas, retaining the natural texture of the paper in dark-colored areas.
Konica Minolta’s Simitri Toner is manufactured in a polymerization process. Toner particles are produced by combining resin ingredients with wax and coloring agent (color pigment) through a chemical reaction.
The toner particle forming process requires precision control of the agglutination reaction. In 2000, Konica Minolta became the first company in the world to introduce polymerized toner in MFPs. Since then, the company has taken the lead in improving polymerized toner and upgrading technology. Today, the size and configuration of the toner particles can be flexibly controlled. In addition, resin ingredients, wax, and color pigment can be arranged in toner particles as designed. This microcontrol technology has enabled (i) appropriate arrangement of resin and wax required for low-temperature fixing and (ii) uniform dissolution of high-concentration color pigment in each toner particle (diameter: approx. 6 μm).