JPH01122474A - Searial printer printing mechanism device - Google Patents

Abstract

PURPOSE:To eliminate irregularities in printing shade to enhance a printing quality, by a method wherein, a gap between a medium to be printed and a printer head is measured, and a printing is carried out while a gap size is kept constant by varying the position of the printer head. CONSTITUTION:A printer head 1 travels in a printing direction together with a printer head drive part 3. Gap measuring parts 2a, 2b being vertically moved by the printer head drive part 3 are installed to a hold part 10 formed as an integral part of the printer head 1 positionally symmetrically to each other in a printing direction. Movable parts 11a, 11b at the top ends of the gap measuring parts 2a, 2b appear as a gap X between the printer head 1 and a medium 5 to be printed is changed to measure the gap X. A drive circuit 9 outputting a drive signal to the printer head drive part 3 controls the vertical drive of the printer head 1 so that the gap X is made optimum when the printer head 1 reaches the gap measuring part 2a. Then, according to a signal sequentially outputted from the gap measuring part 2a a printing is carried out while a gap between the printer head 1 and the medium 5 is kept constant.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a serial printer printing mechanism device, and in particular to a serial printer suitable for a serial printer that prints on a print medium of uneven thickness such as a bankbook. The present invention relates to a printing mechanism device.

[Prior Art] Conventionally, there have been two methods for adjusting the printing pressure in a serial printer printing mechanism device that prints on a printing medium with uneven thickness, such as a bankbook. The first method is
Printing is performed by fixing the gap between the printer head and the platen at a constant level.The second method is to press the printer head against the medium to be printed and print by applying a constant force.

[Problems to be Solved] In the printer printing mechanism device employing the first conventional method described above, the platen gap must be adjusted each time according to the difference in the thickness of the medium to be printed. In the second method, if the thickness of the printing medium is not uniform, v:i light unevenness occurs in the printing. Therefore, both of them have the disadvantage that the print quality deteriorates if the thickness of the medium to be printed changes during printing, and it is difficult to perform high-quality printing on media such as bankbooks where the left and right thickness varies depending on the number of pages turned. There was a problem that printing was difficult.

[Means for Solving Problems] The serial printer printing mechanism device of the present invention includes a printer head, a printer head drive unit that variably drives the gap between the printer head and the print medium, and a change in the gap as the printer head is driven. The apparatus is configured to include a gap measurement section that measures and detects the gap measurement section, and a control section that drives and controls the printer head drive section based on information from the gap measurement section.

[Example] Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram of an embodiment of the present invention. 1 in the figure is a printer head, and this printer head 1 moves in the printing direction (horizontal direction in the figure) together with the printer head drive unit 3.
Moreover, it can be moved up and down by the printer head drive section 3. 2a.

Reference numeral 2b denotes a gap measuring section, which is attached one by one to the holding section 10 integrated with the printer head 1 at symmetrical positions in the printing direction. The movable parts 11a and 11b at the tips move in and out so that the gap X can be measured. By the way, 6 in the figure is the platen.

FIG. 2 is a block diagram of the control section 4 of the present invention, which includes amplification circuits 7a and 7b that receive the output signals of the gap measurement sections 2a and 2b and output an amplified signal. It is provided with delay circuits 8a and 8b that delay the outputs of the output terminals a and 7b by a predetermined time t and output them, and a drive circuit 9 that outputs a drive signal to the printer head drive unit 3 based on the delayed outputs.

Next, the operation of this embodiment will be explained.

First, it is assumed that the printer head 1 is moving to the right in the figure at a speed V and printing. Assuming that the distance between the printer head 1 and the gap measuring section 2a on the right side in the figure is 2, the time required for the printer head 1 to reach the position of the gap measuring section 2a at the relevant time is t = 42/v. Therefore, the signal from the gap measurement section 2a is amplified by the amplification circuit 7a,
1. Delayed by time t through delay circuit 8a. The signal is input to the drive circuit 9. As a result, the drive circuit 9 controls driving up and down so that the gap X becomes optimal when the printer head 1 reaches the after position of the gap measuring section 2a. Then, printing is performed while the gap between the printer head 1 and the medium 5 is kept constant by a signal from the sequential gap measuring section 2a.

When the printer head 1 moves from right to left, the same operation is performed using the gap measuring section 2b, amplification circuit 7b, and delay circuit 8b on the other side.

[Effects of the Invention] As explained above, the present invention eliminates uneven printing shading by measuring the gap between the printing medium and the printer head and changing the position of the printer head to print while keeping the gap dimension constant. This has the effect of improving printing quality.

Additionally, in the past, it was necessary to mechanically adjust the gap between the printer head and platen to improve printing quality.
The present invention can be easily carried out because it is only necessary to adjust the setting values of the drive circuit.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment of the present invention, and FIG. 2 is a block diagram of a control section in FIG. 1. 1: Printer head 2a, 2b: Gap measurement section 3: Printer head drive section 4: Control section 5: Medium 7a, 7b: Gear lug widening section 8a, 8b: Delay circuit (right) 9: Drive circuit X: Gap

Claims (1)

[Claims] a printer head, a printer head drive section that variably drives a gap between the printer head and a print medium, a gap measurement section that measures and detects a change in the gap as the printer head is driven, and information from the gap measurement section. and a control section for driving and controlling the printer head drive section.