Abstract: In an external force measuring system comprising a piezoelectric element 61 or producing a charge when acted on by an external force, and a charge amplifier 7 chargeable with a variation in the charge produced by the piezoelectric element to output a voltage signal, the charge amplifier 7 comprises a feedback loop having an on-off controllable switch 8 connected in parallel therewith. The switch 8 is on-off controlled by a comparator 81 for comparing the output voltage with a reference value and is closed while no external force acts on the element.

Abstract: An apparatus for mounting electronic components on the surface of printed boards by a suction head assembly 4 coupled to a head lift mechanism comprises a force sensor 6 for measuring the pressure exerted on the component by a mounting operation, and a microcomputer 1 for preparing a control signal in accordance with the deviation of the value measured by the force sensor from a desired value of pressure on the component. The rotation of a head lifting motor 51 is controlled based on the control signal.

Abstract: The thermal transfer printer of the present invention is provided with a cam follower mounted on a thermal transfer head in one body and an eccentric cam, which is controlled within a semicircle so as to be positioned at either a first position for releasing it from the cam follower to press the thermal transfer head to a platen or a second position for pressing it to release the thermal transfer head from the platen, as a construction for pressing the thermal transfer head to the platen and releasing the thermal transfer head from the platen, whereby the mechanism for pressing the thermal transfer head to the platen and releasing the thermal transfer head from the platen itself can be remarkably small-sized and is simple in action due to its remarkably small working quantity, the printer can be small-sized as a whole and improved in reliability of operation as well as durability.

Abstract: The thermal transfer printer of the present invention rotates a take-up roll and supply roll for an ink sheet by means of a first friction ring, which transmits the forward directed rotation of a driving motor for carrying the ink sheet to a take-up roll for the ink sheet by the friction force thereof when the ink sheet is carried in the forward direction and applies the brake power to the take-up roll for the ink sheet by frictional force thereof when the ink sheet is carried in the backward direction, and a second friction ring, which transmits the backwardly directed rotation of the driving motor to a supply roll for the ink sheet by the frictional force thereof when the ink sheet is carried in the backward direction and applies the brake power to the supply roll by the frictional force thereof when the ink sheet is carried in the forward direction.

Abstract: The thermal transfer printer of the present invention prevents slackening of recording paper by exerting a braking force upon a recording paper roll to give a back tension to the recording paper when one of the colors of an ink sheet coated with inks of a plurality of colors is thermal-transfer-printed. The recording paper is unwound from the roll thereof in the forward direction and by rotating the recording paper roll in the backward direction the recording paper is rewound. A roller for carrying the recording paper is stopped or braked at the downstream side of the platen when the recording paper is carried in the backward direction for the thermal transfer printing by the next color.

Abstract: A thermal transfer printer of this invention is provided with recording paper carrier rollers disposed on both the upstream side and the downstream side of the thermal transfer head along the paper carrying direction and, further, with a sensor for detecting as to whether or not the recording paper is present on the downstream side lower than the carrier roller disposed on the downstream side along the paper carrying direction. In setting the recording paper for the first time, initial position setting of the recording paper depends on detection of the arrival of the foremost end of the paper at the carrier roller on the downstream side and, when the sensor detects the absence of the paper in the backward carrying thereof after completing the printing with one color, control for stopping backward carrying is performed.

Abstract: A recording apparatus and, more particularly, a so-called thermal printer employs a thermal head as a recording head. A platen roller is in pressing engagement with the recording head and recording elements pass between the two. Biasing forces exerted on opposite ends of the recording head cause it to deform slightly. To accommodate for this deformation, the diameter of the platen roller is greater in the middle than at its opposite ends. This construction assures that both the recording head and the platen roller are pressed against each other under a uniform force, so that ink density irregularity on the recording paper, creasing of the recording paper and the ink sheet, and recording density irregularity resulting therefrom can be prevented, and thus stable recording performance can be assured.

Abstract: A thermal printer of the present invention is basically constructed to use roll form printing paper, but able to use also fan-fold form printing paper by mounting to a casing; a guide shaft for fan-fold form printing paper instead of a roll for roll form printing paper; and a guide unit for fan-fold form printing paper, provided with side plates for regulating both side edges of fan-fold printing paper and with a press plate for restricting the upper surface of the same, and mounted to the casing in condition of being connected to an opening between the casing and the rear end of a cover for the casing.