JPS6327286A - Printer - Google Patents

Abstract

PURPOSE:To simplify hardware around a printing head, by mounting a means for judging whether the printing head is mounted on a printer main body from the data read by the thermistor of the printing head and a means for displaying the non-mounting of the printing head when no printing head is mounted. CONSTITUTION:The thermistor 3 arranged to a printing head 1 applies analogue data (10) at usual temp. of 5-65 deg.C and said data is converted to HEX (hexadecimal) data in CPU4 (20). When no printing head is mounted, the circuit in a carrier 2 is opened and the resistance value between terminals to be originally connected of the thermistor becomes infinite and the data received by CPU comes to FFH. Then, CPU judges whether the data is FFH (0) and, when the data is not FFH, the transfer to usual processing is performed (60) and, when the data is FFH, it is judged that no head is mounted and, in an operator panel lamp, the putting-ON/OFF of head non-mounting display is carried out (40). As error processing, this state is held (50) until the power source of a printer main body is cut off. Therefore, the hardware around the printing head can be simplified without requiring a special circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to printers, and particularly to thermal printers.

[Conventional technology]

In printers in which the print head can be easily attached, detached, and replaced, it is possible to accidentally operate the printer with the print head completely unattached or with the print head improperly attached, which may cause printing defects or malfunctions. In order to avoid this problem, printers of this type have conventionally installed a special circuit as shown in FIG. 3 as a means for fully determining whether a head is attached.

[Problem that the invention seeks to solve]

Thermal printers print by applying heat to each dot in the print head and using that heat to melt the ink on an ink ribbon and transferring the ink to paper, or by using thermal paper without a ribbon. However, when printing continuously, the heat from the previous print remains in each dot of the print head, and more heat is applied to each dot of the print head than is required to print the next character. Because of this phenomenon, the letters become crushed, so the heat accumulation in the hept must be controlled. In a conventional printer, as shown in FIG. 3, a connector 100 is attached to the print head, and a circuit 200 must be separately designed to detect when the connector is inserted into the carrier that the RAD is attached to the print head. As a result, the hardware around the print head becomes complicated and large, which is a drawback.

[Means to solve the problem fe]

The printer of the present invention includes a print head equipped with a thermistor, a means for determining whether the print head is attached to the printer body based on data read from the thermistor, and a means for determining whether the print head is attached to the printer main body, and a means for determining that if the print head is not attached. and display means.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of the present invention, and FIG. 2 is a flowchart of one embodiment. The thermistor 3 installed in the print head 1 provides analog data at a normal temperature f5°C to 65°C (10)).
4, convert to HEX (hexadecimal) data (20
). At this time, the HEX data to be converted is 1 byte, and the setting is such that the possible values at normal temperatures are 03H to IOH. If the print head is not attached, the circuit in carrier 2 becomes open, and the resistance value between the terminals to which the thermistor should normally be connected becomes infinite, causing C
The data received by PU becomes FF■I.

Therefore, if the CPU speed data is not 30χ FFH, it is difficult to judge whether FFI-1 is FF I-1, and if it is not 30χ FFH, the process goes to normal processing. OPP) lamp flashes (4o) to indicate that the head is not installed.

Then, as an error process, this state is maintained until the printer main body is powered off (50).

〔Effect of the invention〕

As explained above, the present invention makes it possible to simplify the hardware around the print head without requiring a special circuit by determining whether the print head is attached based on data read from the head thermistor. A compact device with the effect of providing ft.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the present invention, FIG. 2 is a flowchart of the present invention, and FIG. 3 is a block diagram of a conventional example.

Claims (1)

[Claims] A print head equipped with a thermistor, a means for determining whether the print head is correctly installed in the printer body based on data read from the thermistor, and a means for displaying a message to that effect if the print head is not installed or is installed incorrectly. A printer characterized by having: