1. Field of the Invention
The present invention relates to an image forming device, a bias voltage control method for the image forming device, and a computer program product.
2. Description of the Related Art
In an image forming device, with the aim of achieving reduction in the cost of a high-voltage power supply board, a technology is known in which an imaging sequence and an output constraint are set and a common transformer is used for charging and developing purposes; or a technology is known in which a constant-voltage element is configured in between outputs, and the output bias potential difference is maintained at a constant level so as to reduce the terminals of a high-voltage output unit.
For example, in Japanese Patent Application Laid-open No. 2012-53350, a technology is disclosed in which, with the aim of achieving reduction in the cost of a high-voltage power supply, a common transformer is used for a charging grid and a developing output. Moreover, a technology is disclosed in which constant-voltage elements are connected in between a regulation output and a developing output of a developing device, and the potential; difference between those outputs is maintained at a constant level. With that, in a high-voltage output unit, it becomes possible to use the same terminal for the regulation output and the developing output without making the circuitry complex (for example, see Japanese Patent No. 3507571).
However, in the conventional technologies mentioned above, in the case in which developing of reverse polarity to the polarity of charging is to be output for the purpose of cleaning a photosensitive member, it is not possible to obtain the desired potential difference between the constant-voltage elements. Hence, it is not possible to perform photosensitive member cleaning in a stable manner.
In view of the issues mentioned above, there is a need to enable cleaning of a photosensitive member in a stable manner without making the circuitry complex.