JPH02192975A - Automatic interprinted character clearance adjusting mechanism - Google Patents

Abstract

PURPOSE:To use conditions for driving a stepping motor as profile data adjusted to temperature and allow the displacement of a carrier unit to be set to a constant value by providing a temperature detector which detects the internal temperatures of a device, and a control section which selects specific profiles for determining a clearance between printed characters from among those profiles based on an output from the temperature detector. CONSTITUTION:This mechanism has a temperature detector 11 installed inside a device (e.g. a thermister) and a control section 12 which controls the drive of a stepping motor 10 based on a detected temperature. An eccentric round shaft 7 rotates due to a spring 9, and a process in which a carrier unit 3 comes in contact with printing paper 1 is the same as that of a conventional mechanism. Next, the number of steps by which the printing paper 1 is returned to a printing position is set as required and the printing position is controlled so that it can be adjusted in accordance with circumstances. The (c) to (d1) in the figure is generally set so that it becomes a low value at low temperature and a high value at high temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic printing gap adjustment mechanism, and more particularly to an automatic printing gap adjustment mechanism for a dot matrix printer.

[Prior Art] A conventional automatic printing gap adjustment mechanism of this type will be explained with reference to FIGS. 3 and 4. FIG. 3 is a schematic plan view of the configuration, and FIG. 4 is a graph showing an outline of the operation.

As shown in FIG. 3, one round shaft 4 and an eccentric round shaft 7 supported by an eccentric structure are passed through the carrier unit 3 on which the printing pad 6 and the paper detecting member 5 are mounted. The rotation of the eccentric round shaft 7 causes the carrier unit 3 to rotate around the round shaft 4, thereby widening or narrowing the gap between the printing pad 6 and the printing paper 1.

Print paper 1 is wound around a platen 2. A gear reduction mechanism 8 and a step motor 10 are directly connected to the eccentric round shaft 7. Furthermore, a spring 9 is attached to the eccentric round shaft 7 to always apply rotational force to the round shaft 7 in one direction.

The following is an overview of the operation.

The print head 7 is returned to the print head retracted position fia by a control section (not shown). At this time, the step motor 10
However, when a paper detection command is received, the hold of the step motor 10 is broken and the carrier unit moves by the force of the spring 9 until the paper detection member 4 comes into contact with the printing paper 1 (a- in FIG. 4). b).

Next, the step motor 10 is driven by a predetermined number of steps in the direction opposite to the direction of rotation by the spring and held (c-d in FIG. 4), which becomes the printing position.

[Problems to be Solved by the Invention] In the above-mentioned conventional automatic printing gap adjustment mechanism, mechanical members, especially bearings and bushings, are easily affected by temperature. In the direction of increasing the load at low temperatures,
Moreover, at high temperatures, the effect is small, creating a temperature difference in the rotational force of the eccentric round shaft 7. As a result, the paper detection member 4
This has the disadvantage that the pressing force changes, the paper contact position varies, and the printing position also varies.

[Means for Solving the Problems] The present invention was made to solve the above problems, and as a means for solving the problems, the present invention provides a carrier unit equipped with a print head and a paper detection member of a dot matrix printer, A round shaft on the platen side that is passed through the carrier unit, an eccentric round shaft supported by an eccentric structure at a position far from the platen, a step motor connected to the eccentric round shaft, and a step motor that drives the step motor. In the automatic printing gap adjustment mechanism, the automatic printing gap adjustment mechanism includes a temperature detector that detects the temperature inside the neck mounting, a plurality of profiles that determine the printing gap, and a specific profile that is selected based on the output of the temperature sensor. The configuration includes a control section.

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

FIG. 1 is a schematic plan view showing an embodiment of the present invention, and FIG. 2 is a graph showing an outline of its operation.

In the figure, 1 is a printing paper, 2 is a platen, 3 is a carrier unit, 4 is a round shaft, 5 is a paper detection member, 6 is a print head, 7 is an eccentric round shaft, 8 is a gear reduction mechanism, and 9 is a spring. The configuration is the same as the conventional one, so the explanation will be omitted.

Further, 11 in FIG. 1 indicates a temperature detector (for example, a thermistor) installed in the apparatus, and 12 indicates a control section that controls the drive of the step motor 10 based on the detected temperature.

Next, the operation will be explained with reference to FIG.

The eccentric round shaft 7 is rotated by the spring 9, and the carrier unit 3 comes into contact with the printing paper 1 (a- in FIG. 2).
b) The process is the same as before.

Next, the number of steps for returning the printing paper l to the printing position is set in several stages depending on the temperature setting, and is controlled so that the printing position can be adjusted according to the situation (c-d+d3 in FIG. 2). Generally, the C level in FIG. 2 is set small (C level in FIG. 2) when the temperature is low, and large (C level in FIG. 2) when the temperature is high.

[Effects of the Invention] As explained above, the automatic printing gap adjustment mechanism of the present invention has the following effects:
It has the following effects.

Experience has shown that when the temperature is low, the load on the mechanical part is large, so the rotational force of the eccentric round shaft is small, and the influence of mechanical play and deflection when pressing printing paper is small, so it is suitable for driving a step motor between 0 and 6. Carrier units can be moved significantly without loss. Conversely, when the temperature is high, the rotational force increases, loss increases, and the movement of the carrier unit decreases. By detecting this phenomenon and setting the drive conditions of the step motor to a profile that matches the temperature, it becomes possible to set the movement of the carrier unit to a constant value.

This has the effect of realizing an automatic printing gap adjustment mechanism with higher reliability.

[Brief explanation of the drawing]

Fig. 1 is a schematic plan view of an automatic printing gap adjustment mechanism according to an embodiment of the present invention, Fig. 2 is a graph showing an outline of the operation of this embodiment, and Fig. 3 is a schematic plan view of a conventional automatic printing gap adjustment mechanism. 4 are graphs showing an outline of the operation of the conventional example. l: Printing paper 2 nib laten 3: Carrier unit 4: Round shaft 5: Paper detection member 6: Print head 7: Eccentric round shaft 11: Temperature detector 12: Control unit

Claims (1)

[Claims] a carrier unit equipped with a print head and a paper detection member of a dot matrix printer, one round shaft on the platen side that is passed through each of the carrier units, and an eccentric round shaft supported by an eccentric structure at a position far from the platen; An automatic printing gap adjustment mechanism that includes a step motor connected to the eccentric round shaft and a control unit that controls driving of the step motor, a temperature detector that detects the temperature inside the device, and a plurality of profiles that determine the printing gap. and a control section that selects the specific profile based on the output of the temperature detector.