JP4006668B2 - Printing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mechanism that appropriately maintains a gap between a printing mechanism in a printing apparatus that performs dot printing and a platen that faces the printing mechanism, both at the start of operation and during continuous operation.
[0002]
[Prior art]
A dot printer is a typical printing apparatus that performs dot printing.
[0003]
A dot printer is a printer that performs printing by reciprocating a hammer mechanism section equipped with a printing hammer for performing dot printing in the digit direction by a shuttle mechanism section. The printing hammer has a configuration in which a printing pin is attached to the tip of the leaf spring. The printing hammer is operated by releasing the bending energy previously given to the leaf spring, and dot printing is performed on the printing paper via the ink ribbon. I do.
[0004]
For this reason, if the gap between the hammer mechanism and the platen that supports the printing force of the printing hammer becomes wider than appropriate, energy is dissipated before dot printing is performed, so that proper printing force cannot be obtained or dot printing is not possible. Dedotting may occur due to failure.
[0005]
On the other hand, when the gap between the hammer mechanism and the platen becomes narrow, the tip of the printing pin comes into contact with the printing paper through the ink ribbon, and the ink on the ink ribbon may adhere to the printing paper and stains may occur.
[0006]
Therefore, in order to perform clear printing with a dot printer, it is necessary to maintain an appropriate gap between the hammer mechanism and the platen.
[0007]
Hereinafter, the prior art will be described in detail.
[0008]
The structure of the dot printer will be described with reference to FIG.
[0009]
A hammer mechanism unit 11 on which a printing hammer 13 that performs dot printing is mounted is mounted on the shuttle mechanism unit 12 and reciprocates in the digit direction. The platen 14 that supports the printing force of the printing hammer 13 is disposed to face the hammer mechanism 11 via the printing paper 15 and the ink ribbon 16.
[0010]
The shuttle mechanism 12 transmits a driving force from the linear motor 31 and the like to the timing belt 26 via a power transmission unit (not shown), and further, a hammer mechanism attached to a ball bearing holder (hereinafter referred to as BB holder) 22 via a shift plate 25. The part 11 is reciprocated in the girder direction.
[0011]
The BB holder 22 is positioned by a side stand 30 via a ball bearing 23 and a shaft 21 and by a bearing holder 28 via a slide plate 24 and a bearing 27.
[0012]
Here, when the shuttle mechanism unit 12 is continuously operated, the shuttle base 29 may be thermally deformed mainly by heat generated from the heat source of the linear motor 31. The shuttle base 29 is generally composed of a sheet metal part. When the temperature rises, the shuttle base 29 may be deformed in a convex shape that rises most near the center. That is, the amount of fluctuation in the vertical direction due to thermal deformation of the bearing holder 28 attachment portion of the shuttle base 29 is at both ends of the shuttle mechanism portion 12 in the spar direction and is not easily affected by temperature change. It becomes larger than the amount of fluctuation in the vertical direction due to the thermal expansion. Therefore, the convex deformation of the shuttle base 29 is transmitted to the BB holder 22 via the bearing holder 28, the bearing 27, and the slide plate 24, and as a result, the BB holder 22 rotates around the shaft 21. This rotational movement causes the hammer mechanism 11 to fall down (displacement in the direction of the platen 14), pushing the tip of the printing hammer 13 in the direction of the platen 14, and causing a variation in which the gap between the hammer mechanism and the platen becomes narrower. In some cases, the printing paper is smudged by the ink ribbon.
[0013]
In addition, when left in a cool and dark place, the reverse of the above action occurs, causing the gap between the hammer mechanism and the platen to be widened. Printing power may not be obtained, or dedotting may occur.
[0014]
[Problems to be solved by the invention]
As described above, in order to obtain a clear print in the dot printer, it is necessary to maintain an appropriate gap between the hammer mechanism and the platen.
[0015]
However, the gap between the hammer mechanism and the platen fluctuates mainly due to the thermal deformation of the components that make up the shuttle mechanism as the temperature rises due to heat generated from each heat source during continuous operation or when the temperature is lowered when left in a cool and dark place. Then, it becomes impossible to secure an appropriate gap. If the gap is wider than proper, proper printing force may not be obtained, or de-dotting may occur. If the gap is narrower than appropriate, the print paper will be smudged by the ink ribbon. However, there is a possibility that a clear print cannot be obtained.
[0016]
Therefore, an object of the present invention is to provide a printing apparatus that always keeps the gap between the hammer mechanism part and the platen substantially constant without being influenced by thermal deformation of the parts constituting the shuttle mechanism part.
[0017]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, by providing a mechanism that suppresses fluctuations in the gap between the hammer mechanism and the platen by utilizing thermal deformation and thermal expansion accompanying a temperature rise due to heat generation from each heat source, In both continuous operation and continuous operation, an appropriate gap can be ensured and clear printing can be obtained.
[0018]
That is, the invention of this Application according to claim 1 is a dot printing means having a printing element for dot printing, and paper feeding means for feeding the Printout paper, is placed at a certain interval in the position opposed to the printing element A platen, a drive source, a shuttle base that holds the drive source, a power transmission means that transmits power of the drive source, a ball bearing holder that is connected to the shuttle base and holds the dot printing means, In a printing apparatus that includes a shaft that guides the dot printing unit and a side stand that holds the shaft, and performs printing in a process in which the dot printing unit reciprocates in the digit direction, in the vicinity of the center of the shaft in the digit direction. The shaft is fixed to the shaft, the other is fixed to the shuttle base, and the deformation of the shuttle base is transmitted to the shaft. The provided, said shaft when the shuttle base deformation has occurred is configured to forcibly deflect through the shaft guide.
[0019]
According to a second aspect of the present invention, in the printing apparatus according to the first aspect, the shaft guide includes a screw for adjusting the position of the shaft through hole.
[0020]
According to a third aspect of the present invention, in the printing apparatus according to the first or second aspect, the shaft guide is a member having a larger linear expansion coefficient than the sheet metal member .
[0021]
The invention of claim 4, wherein, in the printing apparatus according to any one of 1 to 3, the fixed portion of the shaft in the shaft guide is characterized in that the oblong hole shape.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described with reference to the drawings.
[0023]
FIG. 1 is a side view of a mechanism for suppressing gap fluctuation between the hammer mechanism 11 and the platen 14 of the shuttle mechanism as an example of the present invention.
[0024]
The basic configuration is the same as that of the conventional shuttle mechanism described above, but in addition to this, in the present invention, a shaft guide 1 for suppressing the fluctuation of the gap is provided. As shown in FIG. 2, the shaft guide 1 is attached near the center of the shaft 21 in the beam direction.
[0025]
In this example, the shaft guide 1 is constituted by a sheet metal part divided into two parts, and the adjustment screw 2 can be adjusted in accordance with the height of the shaft 21 from the shuttle base 29 when the shuttle mechanism 12 is assembled. It has a structure.
[0026]
As described above, the shuttle base 29 is thermally deformed during continuous operation or when left in a cool and dark place, and the BB holder 22 rotates around the shaft 21 via the bearing holder 28, the bearing 27, and the slide plate 24. When the motion is caused, the thermal deformation of the shuttle base 29 is transmitted to the shaft 21 via the shaft guide 1 and the shaft 21 is displaced by forcibly giving a deflection in the vertical direction, so that the rotational motion of the BB holder 22 is performed. Suppression (suppresses rotation in the direction that causes the hammer mechanism 11 to be displaced in the direction of the platen 14 during continuous operation, suppresses reverse rotation when left in a cool and dark place), and finally the hammer mechanism 11 and the platen 14 It becomes possible to suppress the fluctuation of the gap between them.
[0027]
FIG. 3 is a side view of a mechanism for suppressing gap fluctuation between the hammer mechanism 11 and the platen 14 of the shuttle mechanism showing another example of the present invention.
[0028]
The shaft guide 1 of the gap fluctuation suppression mechanism shown in FIG. 1 is changed from a sheet metal part to a shaft guide 3 using a member having a large linear expansion coefficient, such as polyacetal.
[0029]
In this example, like the shaft guide 1 shown in FIG. 1, the shaft guide plate 5 is composed of a sheet metal part divided from the shaft guide 3, and the shaft from the upper surface of the shuttle base 29 is assembled when the shuttle mechanism is assembled. The adjustment screw 4 can be adjusted to the height of 21.
[0030]
By using a member having a large linear expansion coefficient for the shaft guide 3 as in this configuration, the amount of fluctuation due to thermal expansion of the shaft guide 3 itself is larger than that of the shaft guide 1 described in FIG. The amount of displacement of the shaft 21 in the vertical direction can be made larger than that of the mechanism described with reference to FIG. 1, and the effect of suppressing the rotational movement of the BB holder 21 can be increased.
[0031]
In addition, by positioning the fixing position by the adjustment screw 4 above the shaft 21, the configuration is such that the effective length of a member having a large linear expansion coefficient, which is the distance from the shuttle base 29 to the fixing position by the adjustment screw 4, is greatly increased. That is, the distance from the shuttle base 29 to the adjusting screw 4 is increased so that the expansion distance (effective displacement length) of the shaft guide 3 can be secured.
[0032]
Therefore, since the rotational movement of the BB holder 22 can be suppressed more than the mechanism described in FIG. 1, it is possible to suppress the fluctuation of the gap between the hammer mechanism portion 11 and the platen 14.
[0033]
Furthermore, in the example shown in FIG. 3, the temperature difference between the normal temperature assumed for general use and the continuous operation, and the temperature difference between the above normal temperature and the temperature when left in a cool and dark place. A member having an appropriate linear expansion coefficient used for the shaft guide 3 so that the vertical movement amount of the slide plate 24 in the vicinity of the bearing 27 and the vertical displacement amount of the shaft 21 in the vicinity of the BB holder 22 substantially coincide with each other. By selecting and further ensuring the above-mentioned effective length of the member, the rotational movement of the BB holder 22 at the time of temperature change can be made almost zero, and the fluctuation of the gap between the hammer mechanism 11 and the platen 14 is offset. It becomes possible to make it.
[0034]
FIG. 4 is a side view of a mechanism for suppressing gap fluctuation between the hammer mechanism 11 and the platen 14 of the shuttle mechanism showing another example of the present invention.
[0035]
Based on the gap fluctuation suppression mechanism shown in FIG. 3, a shaft guide plate 6 having a shaft 21 mounting hole in the shape of a long hole is provided instead of the shaft guide plate 5 of FIG.
[0036]
As described above, it is conceivable to use a resin such as polyacetal for the member having a large linear expansion coefficient used for the shaft guide 3, but such a resin component is restricted in shape by the mounting state on the shuttle mechanism, Furthermore, the direction of the resin affected by the molding conditions of the resin parts (the direction of the crystal is formed in the resin during the molding process, and the direction of the linear expansion coefficient is generated). In some cases, thermal deformation may occur in the direction of the platen 14 without forcibly deforming only the direction.
[0037]
For example, when the shaft 21 is pushed in the direction of the platen 14 due to thermal deformation of the shaft guide 3 in the direction of the platen 14 when the temperature rises, the gap between the hammer mechanism 11 and the platen 14 becomes narrow, and the hammer mechanism 11 The effect of the suppression mechanism of the gap fluctuation between the platens 14 is inhibited. Therefore, in this example, the shaft 21 mounting hole of the shaft guide plate 6 is formed in a horizontally long hole shape, and the gap between the horizontally long hole and the shaft 21 serves as a margin, and the displacement of the shaft 21 in the platen 14 direction is the shaft guide 3. And the shaft guide plate 6 is not affected. That is, by displacing the shaft 21 only in the vertical direction, the rotational movement of the BB holder 22 can be suppressed, and the fluctuation of the gap between the hammer mechanism 11 and the platen 14 can be suppressed.
[0038]
【The invention's effect】
As described above in detail, according to the present invention, as the temperature rises due to heat generated from each heat source during continuous operation, or as the temperature drops when left in a cool and dark place, the thermal deformation of components that mainly constitute the shuttle mechanism is mainly performed. When the gap between the hammer mechanism and the platen facing it fluctuates, the position of the tip of the print pin of the hammer mechanism can be adjusted by attaching a member that transmits thermal deformation and using thermal expansion of a member with a large linear expansion coefficient. By moving and maintaining the gap between the hammer mechanism portion and the platen substantially constant, it is possible to obtain clear printing.
[Brief description of the drawings]
FIG. 1 is a side view showing a gap adjusting mechanism as an example of the present invention.
FIG. 2 is a top view showing a gap adjusting mechanism as an example of the present invention.
FIG. 3 is a side view showing a gap adjusting mechanism as another example of the present invention.
FIG. 4 is a side view showing a gap adjusting mechanism as another example of the present invention.
FIG. 5 is a side view of a shuttle mechanism portion of a conventional dot printer.
[Explanation of symbols]
1 and 3 are shaft guides, 2 and 4 are adjustment screws, 5 and 6 are shaft guide plates, 11 is a hammer mechanism, 12 is a shuttle mechanism, 13 is a printing hammer, 14 is a platen, 15 is printing paper, and 16 is Ink ribbon, 21 shaft, 22: ball bearing holder, 23 ball bearing, 24 slide plate, 25 shift plate, 26 timing belt, 27 bearing, 28 bearing holder, 29 shuttle base, 30 A side stand 31 is a linear motor.

Claims (4)

Holding a dot printing means having a printing element for dot printing, and paper feeding means for feeding the Printout paper, a platen which is installed at a certain interval in the position opposed to the printing element, a drive source, the drive source A shuttle base that transmits power of the drive source, a ball bearing holder that is connected to the shuttle base and holds the dot printing means, a shaft that guides the dot printing means, and the shaft In a printing apparatus having a side stand for holding, and performing printing in the process in which the dot printing means reciprocates in the digit direction ,
Near the center of the spar of the shaft, one is fixed to the shaft, the other is fixed to the shuttle base, and a shaft guide is provided so that deformation of the shuttle base is transmitted to the shaft, and deformation of the shuttle base occurs. In some cases, the printing apparatus is configured such that the shaft is forcibly bent through the shaft guide . The printing apparatus according to claim 1 , wherein the shaft guide includes a screw for adjusting the position of the shaft through hole . The printing apparatus according to claim 1, wherein the shaft guide is a member having a linear expansion coefficient larger than that of the sheet metal member . The printing apparatus according to claim 1, wherein a fixing portion of the shaft in the shaft guide has a horizontally long hole shape .

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