JPH05309905A - Printer - Google Patents

Abstract

PURPOSE:To miniaturize a device further, by uniting drive sources such as motors installed independently. CONSTITUTION:A label printer 1 is provided with a rack 13 which is fixed to the main body of the device and a carriage case 27 which reciprocates along the rack 13, and makes a printing part 20 reciprocate while engaging a small gear 21 with the rack 13. The printing part 20 incorporates: a coil spring 29 which causes a thermal head 28 to project at the time of forward movement; a large gear which moves together with the rotating small gear 21 at the time of backward movement and causes the thermal head 28 to retract against the energizing force of the coil spring; a follower plate 23; and an arm 26. The printer 1 is further provided with a reset mechanism which, when the printing part 20 returns to its initial position, releases the rack 13 and the small gear 21 from their engagement and causes the thermal head 28 to project by the coil spring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus for printing a character string input in advance on a specific paper such as a label sheet or a postcard in which a plurality of labels are arranged.

[0002]

2. Description of the Related Art As a printing mechanism of a conventional printing apparatus, there is widely known one that reciprocates a carriage equipped with a print head and the like during printing. The carriage is equipped with a mechanism for projecting and retracting the print head. With the movement of the carriage, the print head is projected outside the carriage when printing is performed, and the carriage moves without printing. In this case, the projecting print head is retracted, and the printing process is continuously performed over a plurality of lines while repeating this operation. This carriage also serves as a cassette holder for mounting the ribbon cassette of the ink ribbon, and therefore the carriage also has a winding shaft for winding the ink ribbon.

[0003]

In such a conventional printing apparatus, a carriage motor is used as a drive source for moving the carriage, and an electromagnetic solenoid or the like is used as a drive source for projecting and retracting the print head. Further, for winding the ink ribbon, a motor for rotating and driving the above-described winding shaft is separately provided.

However, since a large number of drive sources such as motors are provided in this way, an extra installation space is required, which is an obstacle to the miniaturization of the device.

The present invention has been made to solve the above problems, and provides a printing apparatus that integrates drive sources such as individually installed motors and enables further downsizing of the apparatus. The purpose is to provide.

[0006]

A printer according to the present invention comprises a rack fixed to the main body of the apparatus and arranged in a direction orthogonal to the paper insertion direction, and a support base that reciprocates along the rack. Prepare The support base includes a print head that prints on paper, a pinion gear that meshes with the rack and that rotates forward and backward as the support reciprocates, and when the support base moves forward along the rack. , The biasing means for causing the print head to project in the direction of the paper to be printed, and when the support base moves back along the rack, it works in conjunction with the rotation of the pinion gear to resist the biasing force of the biasing means. A head retreating means for retreating the print head, and when the support base reciprocates once and returns to the initial position, the engagement between the rack and the pinion gear is temporarily released, and the print head is projected by the biasing means. It is what

Further, the rack is provided with teeth at positions other than the initial position, and when the support table reaches the initial position, the pinion gear provided on the support table has a lack of teeth on the rack. A mechanism for temporarily disengaging the rack and the pinion gear by reaching the above-mentioned location can be used.

Further, the printing apparatus may be provided with a braking member that comes into contact with the pinion gear that is disengaged from the rack and restricts the rotation of the pinion gear.

[0009]

[Operation] When the support base starts to move when printing is performed,
The pinion gear meshing with the rack rotates. The rotation of the pinion gear drives the head retracting means, and the retracting operation of the print head by the head retracting means is stopped. For this reason,
The print head receives the urging force of the urging means and projects toward the paper to be printed. Further, when the support base starts moving in the opposite direction, the pinion gear meshed with the rack starts rotating in the opposite direction, and the head retracting means interlocking with this rotation moves the print head against the bias of the biasing means. Retreat.

When the support base reciprocates once and returns to the initial position, the engagement between the rack and the pinion gear is released, and the pinion gear is released. This releases the restraining force of the head retreating means that is interlocked with the pinion gear to be in the released state, and as a result, the print head projects by receiving the urging force of the urging means. In this way, the print head is reset, and the printing process can be executed immediately below.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A label printing apparatus for printing a label as a printing apparatus according to the present invention will be described below with reference to the accompanying drawings.

1 to 3 show the appearance and internal mechanism of the label printing apparatus 1. A label printing device (hereinafter referred to as a device) 1 is a device that prints on each of a large number of labels 4a arranged regularly on a label sheet 4, and is composed of an upper half body 2 and a lower half body 3. An insertion port 5 for the label sheet 4 is formed in the middle. In the upper half 2 of the device 1,
A large number of keys 6 into which characters and the like can be input are arranged, and a display portion 7 formed of a liquid crystal panel for displaying a predetermined number of characters, the number of lines, or input characters and the like is arranged above the keys 6. The lower half 3 is formed with an insertion opening 5 and a feeding path 11 extending rearward from the insertion opening 5, and a guide for guiding the inserted label sheet 4 on the upper surface of the feeding path 11. A roller 9 is provided. Further, behind the guide roller 9, there are provided paper feed rollers 8 which are driven to rotate by the sheet feed motor 16 and feed the inserted label sheet 3 at a total of three places, and further behind that, printing is performed. The unit 20 is provided.

The lower portion of the printing unit 20 is the label sheet 4
Helical shaft 1 arranged in a direction orthogonal to the insertion direction of
The rotation of the carriage motor 14 is transmitted to the spiral shaft 12 through the gear train 15, and the printing unit 20 reciprocates along the rotating spiral shaft 12. .. A rack 13 is installed above the printing unit 20 in parallel with the spiral shaft 12. The tooth portion of the rack 13 is formed in the lower portion so as to face the printing portion 20,
As described later in detail, the gears in the printing unit 20 are
It is in a state of meshing with. A thermal head 28 formed of a dot array capable of printing one character, for example, projects from the lower portion of the printing unit 20, and a rubber platen 17 is provided on the lower half 3 of the thermal head 28. is doing.

The printing section 20 also functions as a cassette holder for mounting a ribbon cassette (not shown) of an ink ribbon.

Here, the printing operation of the apparatus 1 will be schematically described. First, the apparatus 1 has a guide side wall 18 formed on the left side of the insertion port 5, and the label sheet 4 is inserted from the insertion port 5 while abutting the left side of the label sheet 4 against the side wall 18. This is because the mechanism for performing the printing process is based on the front end (front left corner) of the left side of the label sheet 4 into which the device 1 is inserted. The label sheet 4 is positioned by bringing it into contact with. When the label sheet 4 is inserted through the insertion port 5 in this manner, the label sheet 4 is sent to the rear side by the paper feed roller 8 inside the apparatus, and when the label sheet 4 reaches a predetermined position, printing is performed by the printing unit 20. To be done. When the printing unit 20 moves from the left end of the apparatus 1 which is the reference position of the printing process to the right side, the thermal head 28 is projected along with the movement in this direction,
Further, when the printing unit 20 moves toward the left end for returning to the initial position, the thermal head 28 is mechanically retracted along with the movement in this direction. After the printing is completed and a predetermined character string is printed on each label 4a, the label sheet 4 is discharged from the discharge port 10 on the back surface.

Here, the mechanism of the printing unit 20 which mechanically drives the thermal head 28 in accordance with such movement will be described in detail. First, the internal structure of the printing unit 20 is shown in FIG.
Through FIG. The printing portion 20 has an outer shell portion formed as a carriage case 27, and inside thereof, a small gear 2 as a pinion that meshes with the rack 13 described above.
1 and a large gear 22 that meshes with and interlocks with the small gear 21. Further, one side surface of the large gear 22 is arranged coaxially with this gear and a constant frictional force is exerted between the large gear 22 and the large gear 22. The driven plate 23 frictionally engages with each other. The driven plate 23 rotates integrally with the large gear 22, but when a force against this frictional force is applied to the driven plate 23 from the outside, the driven plate 23 is rotated.
Stops at that position and begins sliding on the gear wheel 22.
This is a so-called clutch mechanism (see FIG. 5).

Further, the outer periphery of the large gear 22 is provided with a planetary gear 24 which meshes with the large gear 22 and rotates around the outer periphery thereof. The planetary gear 24 is integrally supported by a driven plate 23. There is. Therefore, the planetary gear 24 is driven by the large gear 2 as the driven plate 23 slides with respect to the large gear 22.
The outer circumference is rotated while meshing with 2.

Further, a winding shaft 25 for winding the ink ribbon is disposed adjacent to the large gear 22 and the driven plate 23, and the gear portion 25a at the base end portion thereof is a rotating planetary gear. The structure is such that it abuts and meshes with 24. The winding shaft 25 and the gear portion 25a at the base end are frictionally engaged with each other with a constant friction force.

A V-shaped locking piece 23a is formed on the side surface of the driven plate 23 so as to project therefrom.
Inside the character groove, an arm 2 rotatable about the base end 26a is provided.
The front end of 6 is engaged. Further, the arm 26 is engaged with the projecting engagement portion 28'a at the upper end of the head member 28 'which is integrated with the thermal head 28, and the tilting of the arm 26 causes the head member 28' to move up and down, whereby The thermal head 28 is projected and retracted. A coil spring 29 is in contact with the upper end of the head member 28 ', and the coil spring 29 is used for the carriage case 2.
7, the head member 28 'is constantly pressed downward by a reaction force.

Next, the operation of each constituent element of the printing unit 20 having the above-described structure will be described.

First, when printing is performed as described above, the printing unit 20 that was initially in the state of FIG. 4B is moved in the direction indicated by arrow A in FIG. 4A. Then, along with this movement, the small gear 21, the large gear 22, and the driven plate 23
Rotates in the direction shown, and the planetary gear 24 also rotates around the outer periphery of the large gear 22 accordingly. Since the V-shaped locking piece 23a also tilts due to the rotation of the driven plate 23, the coil spring 29
The head member 28 ′ is moved downward by the pressing force of, and the thermal head 28 is projected. At this time, the arm 26 is also pressed by the protruding engagement portion 28'a and tilts downward about the base end portion 26a (FIG. 4A). As the rotation further progresses, the planetary gear 24 becomes the gear portion 25a of the winding shaft 25.
And the driven plate 23 is prevented from rotating further.
As a result, a force against the frictional force acts on the driven plate 23, and the driven plate 23 stops at that position thereafter, and the large gear 2
Start sliding against 2. After that, the printing unit 20 continues to move, but the rotation of the small gear 21 is transmitted to the gear unit 25a via the large gear 22 and the planetary gear 24. As a result, the ink ribbon take-up shaft 25 continues to rotate until the movement of the printing unit 20 is stopped.

Next, this movement is stopped and the printing section 20 returns to the reference position, so that the movement is started in the direction indicated by the arrow B in FIG. 4 (b). Along with this movement, the small gear 21, the large gear 22, and the driven plate 23 rotate in the opposite direction to the above as shown in FIG. 4B, and the planetary gear 24 also moves the outer periphery of the large gear 22 along with this. It rotates in the opposite direction to the above. By this rotation, the meshing of the planetary gear 24, which has meshed with the gear portion 25a of the winding shaft 25, is released, and the rotation of the winding shaft 25 is stopped. At the same time, the V-shaped locking piece 23a is also tilted by the rotation of the driven plate 23, and the head member 28 'is pushed upward via the arm 26 against the pressing force of the coil spring 29, and the thermal head 28 is used as a reference. Retract to position. When the rotation further progresses, a part of the driven plate 23 comes into contact with the locking portion 27a of the carriage case 27 to prevent further rotation. As a result, a force against the frictional force is exerted on the driven plate 23, so that the driven plate 23 stops at that position thereafter and starts sliding with respect to the large gear 22. On the other hand, due to this frictional force, the locking piece 23a of the driven plate 23 continues to push up the arm 26 and the head member 28 'upward against the pressing force of the coil spring 29, and the printing unit 20 causes the arrow A in FIG. This state is maintained until the movement starts again in the direction of.

In this way, the printing unit 20 causes the thermal head 28 to protrude and rotates the ink ribbon take-up shaft 25 during the forward movement for printing, and returns the thermal head 28 to the original position during the backward movement. It has a mechanism for reversing and stopping the rotation of the winding shaft 25 to interrupt the winding of the ink ribbon. Moreover, this mechanism uses the rotational force of the small gear 21 that meshes with the rack 13 as a drive source when the printing unit 20 moves in mesh with the rack 13 to perform all mechanically.

The relationship between the movement of the printing unit 20 and the vertical movement of the thermal head 28 will be described. Printing unit 20
However, when the movement starts again in the direction of arrow A (FIG. 4A) from the state of FIG. 4B, the small gear 2
1 starts rotating in the direction shown in FIG. 4A, and in conjunction with this rotation, the large gear 22 and the driven plate 23 rotate in the direction shown. The thermal head 28 is gradually lowered by the series of movements of the respective members. In other words, in order for the thermal head 28 to descend to the specified position, the printing unit 20 must move a certain distance in the direction of arrow A.

Therefore, in the apparatus 1 of this embodiment, a reset mechanism is provided so that the printing process can be started immediately below the printing section 20 which has returned to the initial position, and the apparatus 1 is further miniaturized.

The reset mechanism will be described below. This reset mechanism does not form the teeth 13a on the rack 13, which is the upper part of the initial position where printing is started, but releases the meshing small gear 21 that has reached this position to release it.

The movement of each member before and after the reset state is shown in FIGS. 6 (a) and 6 (b). FIG. 6A shows a state immediately before the reset, and the small gear 21 reaches the end portion of the tooth portion 13 a formed on the rack 13. The thermal head 28 is still in the retracted state, and is housed in the carriage case 27.

When the printing portion 20 further advances in the direction of the arrow B and the small gear 21 reaches a position where the tooth portion 13a is not formed, the small gear 21 is disengaged from the tooth portion 13a and is in a released state. The large gear 22 and the driven plate 23 that interlock with the small gear 21 are also released. As a result, the force that tilts the arm 26 upward disappears, and the head member 28 'moves downward due to the pressing force of the coil spring 29, causing the thermal head 28 to project (FIG. 6B). With this, the reset is completed, and the printing process can be executed from directly below.

At the time of this reset, the coil spring 29
In order to prevent the head member 28 'from suddenly dropping due to the pressing force of, the leaf spring 30 is provided on the back surface side of the rack 13 shown in FIG. 6 (see FIG. 2).

FIG. 7 is an enlarged view showing a mounting location of the leaf spring 30. The leaf spring 30 has a substantially rectangular shape along the rack 13, a front end thereof is bent slightly upward, and a rear end of the leaf spring 30 is fitted into the rack 13 and holds the leaf spring 30. It is integrally connected with. A rubber sheet 33 is attached to the lower surface of the leaf spring 30.
The rotation of the pinion gear 21 is restricted by friction with the pinion 3. It should be noted that this leaf spring 30 is configured such that the holding plate 31 is attached to the rack 1
It is fixed to 3 by using a screw 32.

Here, the operation of the leaf spring 30 will be described. When the printing portion 20 moves back in the direction of the arrow B and returns to the initial position, when it reaches the vicinity of the end portion of the formed tooth portion 13a, the small gear 21 enters the lower side of the leaf spring 30 to move the leaf spring 30. Push up to proceed. Therefore, the small gear 21 rotates while receiving a downward pressing force from the leaf spring 30 and a frictional force with the rubber sheet 33. As the progress further progresses, the small gear 21 becomes the tooth portion 13a of the rack 13.
When it reaches a position where no head is formed, the large gear 22, the driven plate 23, and the arm 26 are released via the small gear 21, and the head member 28 ′ is lowered by the pressing force of the coil spring 29. Become. At this time, since the driven plate 23 rotates due to the downward tilt of the arm 26, the small gear 21 also rotates in conjunction with the driven plate 23, but the rotation is restricted by the frictional force with the rubber sheet 33. It does not rotate abruptly but gradually rotates while contacting the surface of the rubber sheet 33.

Since the rotational speed of the small gear 21 is suppressed at the time of resetting in this way, the large gear 22, the driven plate 23, and the arm 26 that interlock with the small gear 21 also move slowly. The head 28 can be lowered at an appropriate speed. By this action,
The gear mechanism and the thermal head in the printing section may suddenly collide with other members to produce annoying sound, and vibrations due to the collision may adversely affect other electronic circuits arranged in the apparatus 1. Is being prevented.

[0033]

As described above, according to the printing apparatus of the present invention, the support base for supporting the print head or the like is reciprocated along the rack, and the rack is engaged with the pinion gears and is moved forward. Occasionally, a mechanism is adopted in which the print head is projected by the biasing means, and the print head is retracted by the head retracting means in conjunction with the pinion gear when returning.

Therefore, by moving the support table along the rack, it is possible to drive the protrusion and retreat of the print head, so that another drive source dedicated for driving the print head is not required, and the size of the apparatus is further reduced. Can be realized.

According to the printing apparatus of the present invention,
When the support base reciprocates once and returns to the initial position, the meshing between the rack and the pinion gear is temporarily released, and the mechanism that causes the print head to project by the biasing means is adopted. And the required rack length can be minimized,
This contributes to downsizing of the device.

[Brief description of drawings]

FIG. 1 is a perspective view showing an appearance of a printing apparatus according to the present invention.

FIG. 2 is a perspective view showing an internal mechanism of the printing apparatus.

FIG. 3 is a perspective view showing an internal mechanism of the printing apparatus.

4A and 4B are plan views showing the internal mechanism of the printing unit.

FIG. 5 is a schematic perspective view showing a main part of a gear mechanism arranged in a printing unit.

FIG. 6A is a plan view showing the internal mechanism of the printing unit immediately before returning to the initial position, and FIG. 6B is a plan view showing the internal mechanism of the printing unit immediately after returning to the initial position.

FIG. 7 is a plan view schematically showing the back side of the printing unit to show a braking mechanism using a leaf spring.

[Explanation of symbols]

1 ... Label printing device, 4 ... Label sheet (paper), 13
... rack, 20 ... printing section, 21 ... small gear (pinion gear), 22 ... large gear (head retracting means), 23 ... driven plate (head retracting means), 26 ... arm (head retracting means), 27 ... carriage case (Support base), 28 ... Thermal head (printing head), 29 ... Coil spring (biasing means), 30 ... Leaf spring (braking member).

Claims (3)

[Claims] 1. A rack fixed to the main body of the apparatus and arranged in a direction orthogonal to the insertion direction of a sheet, and a support base that reciprocates along the rack, wherein the support base supports the sheet. The print head that prints is meshed with the rack, and when the support base reciprocates, the
A pinion gear that rotates in the reverse direction, an urging unit that causes the print head to project toward the paper to be printed when the support base moves forward along the rack, and the support base runs along the rack. And a head retreating means for retracting the print head against the urging force of the urging means in association with the rotation of the pinion gear when returning to the initial position. When returning, the meshing between the rack and the pinion gear is temporarily released, and the printing head is projected by the urging means. 2. The rack is provided with a tooth portion at a position excluding the initial position, and when the support base reaches the initial position, the pinion gear provided on the support base is The meshing between the rack and the pinion gear is temporarily released by reaching a position where the rack has no tooth portion.
The printing device described. 3. The printer according to claim 1, further comprising a braking member that comes into contact with the pinion gear that is disengaged from the rack and restricts rotation of the pinion gear. The printing device described.