Blow Molding Technology for Complex-shaped Parts

Toner cartridges must hold fine-grained toner in a plastic case without it leaking and supply the necessary amount of toner to the developing system of a multifunction device as needed. In order to prevent toner leakage, seamless parts in the manner of plastic bottles that are made by blow molding are optimal. At Fuji Xerox, however, the injection molding method was used to create toner cartridges, as the side holes on the cartridge (the holes perpendicular to the mold opening direction, as shown in Fig. 1) that are necessary to supply toner to the developing system were not suitable for blow molding.
As listed in Table 1, blow molding has various characteristics other than the ability to prevent toner leakage. In order to take advantage of these characteristics, Fuji Xerox developed an original technology using blow molding to create cartridges with side holes.

Blow molding is generally used in the mass production of items such as plastic bottles. The equipment used for blow molding includes stations for the four processes of pre-form molding, heating, blowing, and ejection. Several tens of parts move through these stations during mass production. Conventionally, complex equipment equipped with slide molds that create holes on the side of the pre-form have rarely been developed due to space limitations. The molding technology developed by Fuji Xerox minimizes the size of the mold by optimizing the pre-form's mold structure and molding conditions, thereby enabling the creation of a blow molding device and technology that can create side holes on multiple parts simultaneously for the first time in the industry. This new development allows the advantages of blow molding to be maximized, such as fewer parts and processes in assembling toner cartridges and a reduced amount of materials used as the plastic can be thinned.

Table 1: Characteristics of Molding Methods for Creating Toner Cartridges
  Blow Molding Injection Molding
Number of parts Few Many
No. of Assembly Processes Few Many
Flexibility in Shape Limited to simple shapes Complex shapes can be created.
Toner Leakage Structure allowing no leakage Requires additional processing

Fig. 1: Toner Cartridge Created Using Blow Molding

Fig. 1: Toner Cartridge Created Using Blow Molding

By developing molding technology internally, we can produce complex-shaped parts that other companies cannot produce, thereby achieving greater flexibility in plastic design. In addition, by adopting shapes that are easy to assemble and methods of combining multiple parts into one, we have improved productivity and stabilized quality in the mass production process.