Dual mode thermal recorder

Claim 1

A chart recorder, for thermal recording on heat sensitive chart paper with a thermal element printhead matrix having individually energizable thermal elements, the matrix being selectively movable across the chart paper in an x-axis and the chart paper being selectively stepped in the y-axis when the xaxis has been traversed a desired distance to provide a successive space in the x-axis, the chart recorder having input means for receiving digital signals representative of the desired thermal elements to be energized and of the desired motion of the printhead matrix, comprising: a. moving means, connected to the printhead matrix for moving the matrix in either direction in the x-axis between a left and a right margin; b. motion control means, responsive to the digital signals representative of the desired motion, connected to the moving means, for causing the printhead matrix to move to a desired position between the left and right margins; c. graph selection means, responsive to the digital signals representative of the desired thermal elements to be energized, connected to the printhead matrix for enabling the matrix to print a portion of a graph on the chart paper; d. character selection means, responsive to the digital signals representative of the desired thermal elements to be energized, connected to the printhead matrix for enabling the printhead matrix to print a character on the chart paper; and e. enabling means, connected to the graph selection means and to the character selection means, for selectively enabling the graph selection means and the character selection means for printing an annotated graph of characters and graphs on the chart paper.