| 摘要 |
PURPOSE:To reduce the burden on a control unit of a printer, by constructing a light-emitting element selecting circuit of a shift register storing data for two blocks, two latch circuits and an output circuit for one block, and by outputting one data for the two blocks in the forward direction and the other in the reverse direction. CONSTITUTION:Data stored in a shift register 22 are the printing data for first and second blocks, and the preceding data for the first block are latched in a latch circuit 24. The data for the first block are latched in the forward direction in the latch circuit 24, while the data for the second block are latched in the reverse direction in a latch circuit 23. A strobe signal STR is given to an output circuit 25, a signal VK1 is given to a transistor Q1 to turn it ON, and a first LED block B is lighted thereby. By a signal VK2, likewise, a transistor Q2 is turned ON and LEDs of a second LED block B2 are lighted. Since an anode is connected in reverse correspondence to the LEDs of the block B2, they are lighted sequentially from the left side to the right in the sequence of data bits. Lighting operations for third and fourth blocks are conducted likewise, and thereafter the lighting operation for every two blocks is repeated. |
