JPH02297459A - Thermal head inspection equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention comprises a plurality of heating elements, a common electrode commonly connected to all the heating elements, and individual electrodes provided and arranged for each heating element. The present invention relates to an inspection device for inspecting a heating element of a thermal head.

(Prior art) Heat generating elements are arranged in rows on a substrate through a thin film or thick film forming process, photolithography, etching, etc., a common electrode and individual electrodes are formed, and a protective film is formed. The heating board of the thermal head in the heated state is inspected to see if the resistance value of the heating element is within a normal range.

In a thermal head equipped with a common electrode commonly connected to all heating elements and individual electrodes for each heating element, the resistance value of the heating elements is tested by applying a testing probe between the common electrode and the individual electrodes. be able to. With a long thermal head, it is not possible to apply the probe to the common electrode and all the individual electrodes at the same time for measurement, so it is necessary to divide the individual electrodes into blocks of, for example, 32 or 64, and use the blocks as a reference. The probes on the individual pole side are pressed against each block, and the probes are moved at a pitch of each block. At this time, the probe pressed against the common electrode also moves for each individual electrode test block. For this reason, what is conventionally used is what is called a probe card, which includes, for example, a terminal pressed against a common electrode and a terminal pressed against a plurality of individual electrodes of one block.

(Problem to be Solved by the Invention) Since the common electrode testing terminals are also moved as the individual electrode testing terminals are moved, the area on the thermal head where the common electrode terminals come in contact with each block of individual electrodes is large. is necessary. In that area, the common electrode must be exposed from the protective film, and that area is required as an area other than the wiring pattern for simply passing the current that generates heat through the heating element.

If there is a defect on the common electrode side or a common electrode is not provided for each inspection unit, and there is no longer a part to press the common electrode terminal against the common electrode, perform an inspection. become unable to do so.

Further, since a region for pressing the test terminal along the heat generating element array is required in the common electrode region, the substrate width becomes wider. This is because thermal beds are generally not manufactured one by one, but are formed on large substrates containing multiple sheets at the same time, so the number of heat-generating substrates that can be formed at one time is reduced. The cost will be high.

The present invention eliminates the inconvenience of not being able to perform inspection by fixing the terminal on the common electrode side among the inspection terminals despite the movement of the terminal on the individual electrode side. It is an object of the present invention to provide an inspection device that can reduce the width of the substrate by eliminating the need for the heating element to be provided along the array of heating elements.

(Means for Solving the Problems) In the present invention, the sample stage on which the thermal head to be inspected is placed is electrically conductive. The common terminal for testing that contacts the common electrode is in contact with one fixed location of the common electrode of the thermal head, and the common electrode is electrically connected to the sample stage. The terminal on the individual electrode side is a probe having a plurality of terminals in units of blocks, and the probe is configured to be movable in units of blocks of individual electrodes. The test device main body is connected to a sample stage and a probe for an individual electrode, and thereby tests the resistance value of a heating element connected to the probe.

(Example) Figure 1 is a schematic perspective view showing one example, Figure 2 is an enlarged view of the common terminal part in the same example, and Figure 3 is a thermal head - common terminal for inspection and individual electrodes. FIG. 3 is a plan view showing how the probe is pressed against the probe.

FIG. 4 is a sectional view showing a state in which the common terminal for inspection is pressed against the common electrode.

In FIG. 1, reference numeral 2 denotes a metal conductive sample stage, on the top of which a thermal hemometer 1<4 to be inspected is placed.

A metal shaft 6 is fixed to the side surface of the sample stage 2 with screws. A terminal support portion 8 is attached to the shaft 6 so as to be slidable along the shaft. The support portion 8 is provided with a common terminal 10 that contacts the common electrode of the thermal head 4, and the common terminal 10 can be moved in the horizontal direction by turning a dial gauge 12. The common terminal 1o is, for example, a needle-shaped one made of tungsten or aluminum. A screw hole is drilled in the support part 8, and a screw rod 1 is inserted into the screw hole.
4 is passed through the threaded rod 14, and the threaded rod 14 is connected to the rotating shaft of a pulse motor 16. The pulse motor 16 is supported by the shaft 6 so that it can move around the shaft 6 together with the support part 8 (
(The illustration of the support mechanism is omitted). Pulse motor 16
The support part 8 can be moved in the vertical direction along the shaft 6 via the threaded rod 14 by the rotation of the support part 8 . The support part 8 also has
It can rotate about the shaft 6 together with the pulse motor 16 and the threaded rod 14 .

As a sensor for detecting that the common terminal 10 has contacted the thermal head 4, as shown in FIG. 2, a sensor terminal 18 that contacts the common terminal ]-0 is provided. When the common terminal 10 comes into contact with the thermal head 4, the sensor terminal 18 separates from the common terminal ]O, and the conduction state between both terminals 10 and 18 is released, so that the test main body 24 detects the thermal head to be inspected by the common terminal ]-○. A cable 620 sends a signal for detecting contact with the thermal head 4 to be inspected, 22 is a socket 1 to 1, and the socket 22 is connected to the main body 24 of the inspection apparatus.

Returning to FIG. 1, 26 is a probe equipped with a terminal that comes into contact with the individual electrodes divided into blocks, and the probe 26 is moved at a pitch of blocks along the arrangement of the individual electrodes.

24 is the main body of the inspection device, in which the sample stage 2 and the probe 2 are used to obtain a signal for inspecting the heating element of the thermal head 4.
6. Reference numeral 25 is a line to RI-1 that connects the inspection apparatus main body 24 and the sample stage 2.

Terminal 28 in FIG. 2 is a preliminary test common terminal and a sensor terminal.

As shown in FIG. 3, an example of the thermal head 4 to be inspected has heating elements 30 arranged in a row on a substrate, with a common electrode 32 formed on one side and a common electrode 32 on the other side. Individual electrodes 34 are formed on the. The common electrode 32 is formed to extend to the individual electrode side, and a protective film 36 is formed on the electrodes 32 and 34 and on the heating element 30, except for the bonding pad portion of the common electrode 32 and the bonding pad portion of the individual electrode 34. is formed.

In FIG. 4, which shows the state in which the common terminal 10 is pressed against the common electrode 32, a resistor 40 is formed on a substrate 38 such as a ceramic substrate whose surface is covered with a glassy glaze layer, and A common electrode 32 is formed. A portion 32a of the common electrode 32 against which the test common terminal 10 is pressed is made thicker by plating or the like.

The portion 32a is exposed from the protective film 36.

In FIG. 1, the thermal head 4 is placed on the sample stage 2, the common terminal 10 is lowered by the pulse motor 16,
The contact of the common terminal 10 with the thermal head 4 is sensed by the inspection device 7 and the main body 24 via the cable 20. The horizontal position of the common terminal 10 is adjusted by a dial gauge 12 so that the common terminal 10 properly contacts the common electrode.

The probe 26 for the individual electrodes is pressed against each block of individual electrodes, and the resistance value of the heating element in each block is tested by the test device main body 24. The test is repeated while the probe 26 is moved block by block. go. Despite the movement of the probe 26, the common terminal 10 in contact with the common electrode remains fixed at one point. A signal from the common terminal 10 is sent via the shaft 6 and the sample stage 2 from the lead wire 25 to the inspection apparatus main body 26.

(Effects of the Invention) In the present invention, since the common terminal that contacts the common electrode is fixed at one point of the common electrode, the other surfaces of the common electrode except for the contact portion can be covered with a protective film. It is no longer necessary to provide common electrode exposed portions for contacting the probe card at multiple locations as in the past, and the range in which the protective film is formed can be set freely.

Since the common electrode contacts the test common terminal at only one point, the degree of freedom in pattern design of the common electrode is increased.

Since it is no longer necessary to provide the contact parts between the common electrode and the common terminal for inspection at multiple locations along the heating element array as in the past, there is no need for a common electrode area for this, and the board width becomes narrower. The number of thermal heads that can be formed increases, contributing to cost reduction.

Conventionally, inspection probes for inspection equipment included both individual electrode terminals and common terminals, but since the probe according to the present invention only needs to be used for individual electrodes, the area of the probe is reduced and simplified, and the probe becomes cheaper.

Furthermore, since the sample stage is used as a conductive path from the common terminal to the inspection device main body, the amount of wiring between the common terminal and the inspection device main body is reduced, making inspection easier.

[Brief explanation of drawings]

Fig. 1 is a perspective view of main parts showing one embodiment, Fig. 2 is a perspective view showing a common terminal portion in the same embodiment, Fig. 3 is a plan view showing a thermal head and an inspection device, and Fig. 4 is a common electrode. FIG. 3 is a cross-sectional view showing a state in which the common terminal is in contact with the common terminal. 2...Sample stage, 4...Thermal head, 8
Support part, 10... Common terminal, 24... Inspection device main body, 26... Probe.

Claims (1)

[Claims] (1) In an apparatus for testing a thermal head equipped with a plurality of heating elements, a common electrode commonly connected to all the heating elements, and individual electrodes provided and arranged for each heating element, the thermal head to be tested is One of the common electrodes of the conductive sample stand to be placed and the thermal head to be inspected on this sample stand.
A common terminal that contacts a point and connects the common electrode with the sample stage, and a plurality of terminals that simultaneously contact individual electrodes of a group of the thermal head to be inspected, and is for individual electrodes that are moved along the individual electrode array. An inspection apparatus comprising a probe and an inspection apparatus main body that is connected to the probe and the sample stage to inspect each heating element of the thermal head to be inspected.