Abstract: The image forming apparatus carries out a monitoring operation in which (i) sensor outputs of the magnetic permeability sensor are periodically sampled, (ii) a time period, corresponding to one (1) circulation period which is required for the developer to be circulated once in the circulation carrying path, is evenly divided into a plurality of blocks, and (iii) an average of the sensor outputs in one (1) block time period corresponding to one (1) block is calculated for each of the plurality of blocks; and determines that toner has run short, in a case where the number of times that the averages of the sensor outputs consecutively exceed a threshold, set to be higher than a reference value of the sensor outputs, becomes not less than the number of the plurality of blocks which correspond to the time period corresponding to one (1) circulation period.

Abstract: Formation of stretchable photovoltaic devices and carriers is described. In some examples, a formation method includes: forming a stretchable carrier including a stretchable part having a given length, the given length being operable to change in response to a force being applied to the stretchable carrier; depositing a photovoltaic cell over a surface of the stretchable carrier; and interconnecting the photovoltaic cell to output terminals.