JPH0541884Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention mainly relates to a head drive device for lifting up and lifting down a serial type recording head in a facsimile machine.

<Prior art> Fig. 5 shows a conventional serial type thermal printer, in which a head carriage 2 to which a thermal head 1 is fixed is slidable on a head slide shaft 4 having a rail-shaped protrusion 3 formed in the axial direction. The head carriage 2 is inserted into the head slide shaft 4 so as to be movable in the printing direction, and the head carriage 2 is engaged with the head slide shaft 4 by the protrusion 3 so as to rotate together with the head slide shaft 4. An actuation lever 5 is provided at one end of the head slide shaft 4, and a plunger 7 of an electromagnetic solenoid 6 is pivotally connected to the actuation lever 5 by a pin. , the head carriage 2 is rotated via the head slide shaft 4 in a direction in which its thermal head 1 is separated from the platen 8. On the other hand, a coil spring 9 is suspended on the actuating lever 7 so as to urge it to rotate in a direction opposite to the direction of rotation by the electromagnetic solenoid 6. When the electromagnetic solenoid 6 is not driven, the head carriage 2 The thermal head 1 is rotated via the head slide shaft 4 by the biasing force, and the thermal head 1 is moved to the platen 8 with the recording paper 10 interposed therebetween.
The recording paper 10 is thermally recorded by the heat generated by the thermal head 1. In addition, a driving pulley 11 serves as a mechanism for transporting the thermal head 1 in the printing direction along the head slide shaft 4.
A part of the belt 13 wound around the driven pulley 12 is fixed to the head carriage 2, and a stepping motor 14 connected to the driving pulley 11 is provided. The head carriage 2 is intermittently moved in the printing direction shown by the arrow by the forwarding movement of the belt 13 by the intermittent drive of the stepping motor 14, and the thermal head 1 is intermittently moved in the printing direction, and the urging force of the coil spring 9 moves the head carriage 2 intermittently in the printing direction shown by the arrow. Thermal recording is performed by the heat generated by the thermal head 1 which is pressed against the recording paper 10 via the slide shaft 4. When the thermal head 1 reaches the end in the printing direction, the electromagnetic solenoid 6 is driven and the plunger 7 is attracted against the biasing force of the coil spring 9.
The thermal head 1 is removed from the platen 8, and in this lift-up state, the head carriage 2 is returned to the initial printing position by the reverse rotation of the stepping motor 14.

<Problems to be Solved by the Invention> However, the head drive mechanism has two serious problems. That is, since the lift-down operation of bringing the thermal head 1 into pressure contact with the platen 8 and the lift-up operation of removing it from the platen 8 are performed by the rotation of the head slide shaft 4, the head slide shaft 4
In addition to forming the protrusion 3 on the head carriage 2, it is necessary to drill an engagement hole to allow the protrusion 3 to slide freely through the head carriage 2. In order to slide and rotate without rattling, it must be manufactured with high dimensional accuracy, and the processing cost is high, which is a factor in increasing costs. on the other hand,
Figure 5 shows a thermal printer as an example.
In the case of a facsimile device, a scanner carriage equipped with a scanner for optically reading originals must be installed so that it can be inserted into the head slide shaft 4 and moved together with the head carriage. A head slide shaft 4 is slidably inserted into a scanner carriage which needs to be simply held so as to slide because the slide shaft 4 is formed with a protrusion 3 without engaging with the protrusion 3. This requires a complicated configuration, which further increases costs. Moreover, facsimile machines are used in a constantly energized state, and the recording head is kept in the head-down state only when receiving data, and is kept in the head-up state during the overwhelmingly common time of waiting for reception. Since the head is turned up by driving the electromagnetic solenoid 6, there is a drawback that the electromagnetic solenoid 6 is energized almost all the time, resulting in high running costs.

Further, since the turning force to the head slide shaft 4 is applied by the operating lever 5 provided at one end of the head slide shaft 4, the position of the head carriage 2 that slides on the head slide shaft 4 causes the thermal head 1 to move toward the recording paper 10. The pressing force is different. As a result, printing becomes uneven and print quality deteriorates.

<Purpose of the invention> The present invention was devised in view of the above-mentioned conventional technical problems, and it is possible to perform the lift-down and lift-up operations of the recording head using a structure using simple-shaped parts that can be manufactured at low processing costs. It is an object of the present invention to provide a head drive mechanism for a recording device that can press the recording head against the platen with a constant pressing force regardless of the moving position of the head carriage. .

<Means for Solving the Problems> In order to achieve the above object, the present invention configures a head drive mechanism of a recording apparatus as follows. That is, the recording apparatus is driven to perform a lift-down operation in which the recording head, which is transported in the printing direction along a head slide shaft, is brought into pressure contact with the platen with a recording sheet interposed therebetween, and a lift-up operation in which the recording head is separated from the platen. In the head drive mechanism, a head carriage to which the recording head is fixed is slidably and rotatably inserted into and attached to the cylindrical head slide shaft, and is attached to the head carriage in a direction perpendicular to the print direction and on a lift-down side. The end of the passive lever integrally protruding from the head is slidably abutted from above against the camshaft, which has a corner formed in the axial direction and is arranged parallel to the head slide shaft. A coil spring having a coil winding portion inserted into the head slide shaft is inserted into the head slide shaft so as to be slidably inserted into the head slide shaft and is engaged with the head carriage so as to move together. A solenoid is provided so that both ends of the camshaft are engaged with the head carriage to bias the head carriage to rotate in the lift-down direction, and the solenoid rotates the camshaft, which is biased to rotate in one direction by an elastic body, in the other direction when driven. When the solenoid is not driven, the head carriage is lifted up by the corner of the camshaft via the passive lever, and the camshaft is rotated by the drive of the solenoid to separate it from the passive lever.

<Function> With the above configuration, during recording operation,
The solenoid is in a driven state and the camshaft is held apart from the passive lever of the head carriage against the biasing force of the elastic body. Therefore, the head carriage, which is rotatable relative to the head slide shaft, is rotated in the lift-down direction by the biasing force of the coil spring engaged therewith, and the recording head is pressed against the platen with the recording paper interposed therebetween. At this time, the recording head is pressed against the platen by the urging force of the coil spring, and since the coil spring moves together with the head carriage, the pressing force of the recording head against the platen is always constant. When the recording head reaches the end in the printing direction, the solenoid is deactivated, the camshaft is rotated by the restoring force of the elastic body, the corner of the camshaft pushes up the passive lever, and the head carriage starts recording. The head is rotated in a direction away from the platen, a lift-up operation is performed, and the passive lever slides on the corner of the camshaft, thereby returning the recording head to the initial printing position while maintaining the lift-up state. The head slide shaft simply slides the head carriage and there is no need to apply rotational force to it. Therefore, a circular bar that can be manufactured at low processing cost can be used, and when applied to a facsimile machine, it can be used as a scanner. It is only necessary to drill a circular hole in the carriage for slidably inserting the head slide shaft, and since the head is in an up state when the solenoid is not driven, running costs are significantly reduced.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

1 to 3 show an embodiment of the present invention applied to a facsimile machine having a serial printing type printing mechanism. In these figures, a head carriage 16 to which a recording head 15 consisting of a thermal head is fixed is shown. , is attached to the head carriage 16 by being slidably and rotatably inserted into the cylindrical head slide shaft 17, and the head carriage 16 is provided with a lift shaft that is perpendicular to the printing direction that moves along the head slide shaft 17. A passive lever 18 is integrally provided on the down side. A scanner slide shaft 19 is installed on one side of the head slide shaft 17 in parallel with the head slide shaft 17, and one end of the scanner slide shaft 19 is slidably inserted into the scanner slide shaft 19, and the other end of the scanner shaft 20 is inserted. A pair of arms 2
1 and 22 are sandwiched on both sides of the head carriage 16 and are slidably inserted into the head slide shaft 17.
The head carriage 16 is adapted to be moved by sliding on both slide shafts 17 and 19, respectively, and the head carriage 16 is moved together by a pair of arm sections 21 and 22. Further, the scanner carriage 20 includes a scanner including an LED light source 23 and the like for optically reading a document (not shown), and scans the document by moving the scanner scanner 20 . and,
A coil spring 24 is interposed between one arm portion 21 and the head carriage 16 by inserting the head slide shaft 17 through the coil portion of the coil spring 24, and both ends of the spring 24 are connected to the locking pins of the scanner carriage 20. 25 and head carriage 1
6, the head carriage 16 is urged to rotate in the direction in which the recording head 15 comes into pressure contact with the platen 26 with the recording paper 27 interposed therebetween. The head carriage 16 is interposed in the gap between the arm portion 21 and the arm portion 21.
will be moved together with

A prismatic camshaft 28 is rotatably installed on the other side of the head slide shaft 17 and parallel thereto.
The passive lever 18 is located above. A camshaft gear 2 is attached to one end of the camshaft 28.
9 are fixed concentrically, and a tooth portion 31 formed on the end surface of a head drift lever 30 is meshed with this camshaft gear 29. This head drift lever 30 and the electromagnetic solenoid 32 of the driving source
A connecting line 34 is suspended between the plunger 33 and the plunger 33 driven by the solenoid 32.
Due to the suction operation, the cam lift lever 30 is swung in the direction of arrow A in FIG. 2 via the connecting line 34.
When the solenoid 32 is not driven, the solenoid 32
The cam lift lever 30 moves in the opposite direction of the arrow A in FIG.
It is being swung in the direction of the arrow. The swing range of the cam lift lever 30 may be restricted by providing stoppers at predetermined intervals on both sides thereof.

Next, the operation of the above embodiment will be explained.
During the printing operation, as shown in FIG. 2, the electromagnetic solenoid 32 is driven to attract the plunger 33, and the cam lift lever 3
0 is swung in the direction of the arrow A, and the camshaft 28 is rotated in the direction of the arrow shown in the figure via the camshaft gear 29 that meshes with the teeth 31 of the cam lift lever 30. It separates from the passive lever 18 in opposition to . Accordingly, the head carriage 16 is rotated in the direction of the arrow shown by the biasing force of the coil spring 24, and the recording head 15 is pressed against the platen 26 with the recording paper 27 interposed therebetween. In this state, the head carriage 16 is intermittently moved in the printing direction by the scanner carriage 20, and the recording paper 27 is moved intermittently in the printing direction.
will be printed on. At this time, coil spring 2
4 is moved together with the head carriage 16, the rotation biasing force of the head carriage 16, that is, the pressing force of the recording head 15 against the platen 26 is always constant regardless of the position of the recording head 15, and uniform printing is achieved. High printing quality can be achieved by pressure.

Then, when the recording head 15 reaches the end in the printing direction, the electromagnetic solenoid 32 becomes non-driven, and the head drift lever 30 swings in the direction of arrow B by the restoring force of the return spring 35, as shown in FIG. The camshaft gear 29 is rotated in the direction of the arrow shown in the figure, and the corner of the camshaft 28 stops with the driven lever 18 pushed up. Therefore, the head carriage 1 is moved by the passive lever 18.
6 is rotated in the direction of the arrow shown in the figure against the biasing force of the coil spring 24, and the recording head 15 is separated from the platen platen 26. In this lifted state, the head carriage 16 is returned to the initial printing position. At this time, the passive lever 18 comes into sliding contact with the corner of the camshaft 28, thereby maintaining the lift-up state. When the head carriage 16 returns to the initial printing position, the electromagnetic solenoid 32 is driven again and the printing operation is started.

It should be noted that facsimile apparatuses are used in a constantly energized state, and the head drive mechanism is activated only when image information is received, and the facsimile apparatus is overwhelmingly in a reception standby state due to the energized state. In the above embodiment,
In the reception standby state, the electromagnetic solenoid 32 remains in a non-driven state, so running costs are reduced due to the power saving effect.

FIG. 4 shows another embodiment of the present invention, in which the same or substantially equivalent parts as in FIGS. 1 to 3 are given the same reference numerals. In the embodiment shown in FIGS. 1 to 3 described above, the driving force of the electromagnetic solenoid 32 is transferred to the camshaft 2 via the head drift lever 30 and the camshaft gear 29.
In contrast, in this embodiment, the head drift lever and the camshaft gear are omitted, and a band-shaped head drift lever is installed at the end of the camshaft 28. 36 is fixed, and a connecting line 34 and a return spring 35 are hooked to both ends of the head drift lever 36, respectively. Although the torque required to rotate the camshaft 28 becomes large, the structure can be simplified. There are advantages.

<Effects of the invention> Since the present invention is constructed and operates as described above, the head drive mechanism of the recording device of the present invention allows the forward and reverse rotation of the camshaft by the drive of the electromagnetic solenoid and the biasing force of the elastic body. Since the head carriage is lifted up and lifted down via a passive lever whose end is in contact with the camshaft from above, the head slide shaft simply slides without applying rotational force to the head carriage. Since it is possible to use a cylindrical shape, the processing cost is significantly reduced, and a considerable cost reduction can be achieved. Moreover, when returning to the initial position while maintaining the lift-up state, the passive lever only slides on the corner of the camshaft, and almost no load is applied, so the head carriage can be moved smoothly, and at this time Since almost no rotational force is applied to the camshaft by the passive lever, the elastic body that holds the camshaft in the lifted-up rotational position may have a small biasing force.

In addition, since the head carriage, which is rotatable relative to the head slide shaft, is provided with a coil spring that moves together with it to apply a pressing force to the recording head, the recording head can be moved independently of the position of the recording head due to movement of the head carriage. The printing pressure is always constant and high printing quality can be obtained.

In particular, when applied to a facsimile device, when the head carriage is moved by a scanner carriage, and when the head slide shaft is provided with a protrusion as in the past and rotates around an axis, the head slide shaft engages with the protrusion. Although it is necessary to provide the scanner carriage with a complicated structure to allow the head to slide on the head slide shaft without any movement, by using the cylindrical head slide shaft as in the present invention, the scanner carriage has a head slide. It is only necessary to drill a hole for the shaft to slide freely through it, which can significantly reduce the cost of the scanner carriage, and since the head is in an up state when the lens is not driven, running costs can be significantly reduced. There are advantages.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of the present invention when applied to a facsimile machine, with Figure 1 being a perspective view, and Figures 2 and 3 being during recording operation, head return, or reception standby, respectively. side view of time,
FIG. 4 is a side view of a portion of another embodiment of the present invention, and FIG. 5 is a perspective view of a conventional head drive mechanism. 15... Recording head, 16... Head carriage, 17... Head slide shaft, 18...
Passive lever, 24... Coil spring, 26...
... platen, 27 ... recording paper, 28 ... camshaft, 32 ... solenoid, 35 ... return spring (elastic body).

Claims (1)

[Scope of utility model registration request] Head drive of a recording device that drives the recording head, which is transported in the printing direction along the head slide shaft, to perform a lift-down operation in which the recording head is brought into pressure contact with the platen with a recording sheet interposed therebetween, and a lift-up operation in which the recording head is separated from the platen. In the mechanism, a head carriage to which the recording head is fixed is slidably and rotatably inserted into and attached to the circular rod-shaped head slide shaft, and the head carriage is integrally attached to the lift down side in a direction perpendicular to the printing direction. The end of the passive lever protruding from above is slidably brought into contact with the camshaft, which has a corner formed in the axial direction and is arranged parallel to the head slide shaft, from above, and the scanner carriage is moved. , a coil spring which is slidably inserted into the head slide shaft and engaged with the head carriage so as to move together, and whose coiled portion is inserted into the head slide shaft is connected to the scanner carriage and the head carriage. A solenoid is provided so that both ends of the camshaft are engaged with the camshaft to rotate the head carriage in the lift-down direction, and a solenoid is provided that rotates the camshaft, which is biased to rotate in one direction by an elastic body, in the other direction when the camshaft is driven. A recording apparatus characterized in that when a solenoid is not driven, a corner of the camshaft lifts up the head carriage via the passive lever, and the drive of the solenoid rotates the camshaft to separate it from the passive lever. Head drive mechanism.