| 摘要 |
An image forming apparatus is provided to form a groove of a grid shape on the surface of a core pipe in the inside of a heat roller to minimize shear stress between adhesive portions when the heat roller rotates, thereby maximizing adhesive strength between the core pipe and a rubber layer. A fusing unit(30) is composed of a heat roller(31) and a press roller(32). The heat roller and the press roller have a core pipe(33), a rubber layer(34), and a mold release layer(35) from each inside of the heat roller and the press roller. The heat roller has additionally a heat member(36) such as a heater coil in the inside of the core pipe. A groove of a predetermined shape is formed on the surface of the core pipe. A plurality of first grooves is installed in a direction or at regular intervals on the surface of the core pipe and a plurality of second grooves is installed in the other direction or at regular intervals on the surface of the core pipe in opposite to the first grooves to form a groove of a grid shape. The first and second grooves are installed slopely for a rotation direction of the heat roller or the press roller.
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