JPH0798410B2 - Positioning device for print head in serial printer - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print head position detection device in a serial printer.

[Prior Art] Conventionally, a print head position detecting device in a serial printer is configured to perform a so-called home sense operation in order to know the position of the print head when the power is turned on. An optical sensor, a micro switch, or the like is used as a position detecting sensor therefor.

[Problems to be Solved] In a conventional device using an optical sensor or a micro switch for detecting the position of a print head, not only these components are naturally required, but also the optical sensor and the like are connected to a circuit board. You also need cables. Therefore, the structure of the printer is complicated and the assembling process is complicated, which is one of the causes of the high cost of the serial printer.

An object of the present invention is to eliminate the need for a conventional position detection sensor that causes high cost, to enable the position of the print head to be detected with a simple configuration, and to facilitate assembly,
It is an object of the present invention to provide a print head position detection device in a serial printer, which can reduce the cost of the printer.

[Means for Solving the Problems] A feature of the present invention is that, on the printer frame side, when the print heads face each other at one end of a moving area of the print heads, the print heads are provided with a print head for printing. A magnet that exerts a magnetic velocity is fixedly arranged on at least one of the plurality of drive coils, and an induced current generated in the drive coil when the magnetic flux acts on the drive coil in the at least one drive coil. Is connected to the detection circuit for detecting the position of the print head.

[Operation] When the print head reciprocates, when a magnetic flux of a magnet provided on the printer frame side is crossed, an induced current is generated in a drive coil incorporated in the print head. This current is detected by the detection circuit to detect the position of the print head.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a platen 2 is rotatably supported on a printer frame 1 of a serial printer, and a guide shaft 3 is provided in parallel with the platen 2 and reciprocates along the guide shaft. The print head 4 is mounted on the carriage that is moved.

As shown in FIG. 2, the print head 4 contains a plurality of drive coils 5 for driving a plurality of print elements. On the printer frame 1 side, magnetic flux is applied to at least one of the drive coils 5 in the print head 4 at one end of the moving area of the print head 4 as shown in FIG. The permanent magnet 6 exerted is fixedly arranged.

As shown in FIG. 2, a drive signal is supplied from the drive circuit 7 to the drive coils 5 of the print head 4 to drive each print element. The position of the print head 4 is detected in at least one drive coil 5 by detecting an induced current generated in the drive coil when the magnetic flux of the permanent magnet 6 acts on the drive coil, that is, when the magnetic flux traverses the magnetic flux. A detection circuit 8 for detecting is connected.

Next, the operation will be described.

The print head 4 is reciprocally moved along the guide shaft 3,
As shown in the figure, for example, at the home position, the drive coil 5
At least one of ... Crosses the magnetic flux of the magnet 6. Then, an induced current is generated in the drive coil 5, and the induced current is detected by the detection circuit 8 and a detection signal is output.

At this time, since the print head 4 is not in the position for printing, the drive signal is not supplied from the drive circuit 7 to the drive coil 5. Therefore, the detection circuit 8 can accurately detect only the induced current, and detects the position of the print head 4.

A microcomputer (not shown) that controls the printer
Knows that the print head 4 has come to the home position by this detection signal, and performs the necessary home sense operation.

Further, when the print head 4 prints, this print head is in a position not facing the magnet 6, so that the print head 4 does not malfunction due to this magnet.

The mounting position of the magnet 6 is not limited to the rear side of the print head, but when the print head 4 faces each other, a magnetic flux is exerted on at least one of the drive coils 5 incorporated in the print head. It may be forward or downward as long as it can be moved.

[Effect] In the present invention configured as described above, a plurality of drive coils for printing drive, which are conventionally incorporated in the print head, are used as detection coils for position detection, and an induced current is generated in them. Since a magnet is used and the induced current generated in this drive coil is detected by the detection circuit to detect the position of the print head, there is no need for a home sensor or a connecting cable as in the past, and cost is reduced. Can be reduced and the structure is simple, so that assembly can be facilitated.

[Brief description of drawings]

FIG. 1 is a plan view of a main part, and FIG. 2 is a circuit block diagram. 1 ... Printer frame, 2 ... Platen, 4 ... Print head, 5 ... Drive coil, 6 ... Magnet, 8 ... Detection circuit.

Claims (1)

[Claims] 1. A position detecting device for a print head in a serial printer, wherein a print head having a plurality of drive coils for printing built therein is reciprocally moved in parallel with a platen. A magnet that exerts a magnetic flux on at least one of the drive coils in the print head is fixedly disposed at one end of the moving area when the print head is in a position facing the print head, and the at least one drive coil is provided. The printhead in a serial printer is connected to a detection circuit for detecting the position of the printhead by detecting an induced current generated in the drive coil when the magnetic flux acts on the drive coil. Position detection device.