JPS5812155B2 - Thermal printer paper feed device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a paper feeding device for a thermal printer.

Conventionally, when feeding printing paper for printers other than thermal printers, such as dot printers, the print head does not touch the paper, so if you use fanfold paper and feed the paper with a sprocket wheel, it will be more accurate due to the slip between the fanfold paper and the rubber platen. Paper can be fed, but in the case of a thermal printer that has a structure in which a rubber platen and a sprocket foil are integrated, the print head presses the paper against the rubber platen quite strongly.

For this purpose, two parts are called sprocket foil and rubber platen.
The paper is fed by two drive systems.

Now, in the case of paper feeding using a sprocket wheel and rubber platen, the paper feeding drive system is driven in two ways: by the sprocket wheel and by the print head and rubber platen.As a result, the method using sprocket feed is accurate. However, with the method using a print head and a rubber platen, uneven paper feeding occurs due to variations in the diameter of the rubber platen during mass production, slippage between the paper and the rubber platen, or variations in the hardness of the rubber platen and head pressure. This method has the drawback that an error occurs in the amount of paper feed, which is affected by the platen, which normally has a strong paper driving force, and the pins do not engage the holes in the fanfold paper, causing problems such as tearing of the paper and making it impossible to feed the paper.

In order to eliminate the above-mentioned drawbacks, the diameters of the rubber platen and sprocket foil have conventionally been made completely the same, and the print head has been lifted for each line or sheet of paper to be fed. Due to the shortcomings, gradually small errors accumulate, eventually resulting in the above-mentioned shortcomings, and the structure also has the drawback of complicating the structure to lift the print head.

The present invention eliminates the drawbacks of the conventional methods described above and provides a paper feeding device that can accurately feed paper while the printing element remains pressed against the platen and the recording paper.

Hereinafter, the configuration of the device according to the present invention will be explained in detail based on the drawings.

In Figure 1, a rubber platen (roller) 1 and a drive shaft 2 are shown.
are not fixed but are connected via a sliding surface 3, and the rubber platen 1 and print head 4 press a perforated thermal recording paper (hereinafter referred to as fanfold paper) 5.

When the drive shaft 2 rotates, the rubber platen 1 also rotates, and the fanfold paper 5 is sent by friction with the print head, and the fanfold paper 5 is also sent by the rotation of the sprocket foil fixed to the drive shaft 2.

In this case, the diameter of the rubber platen 1 is slightly larger than that of the sprocket foil, so the rubber platen 1
The amount of paper feeding by the sprocket wheel 6 is greater than the amount of paper feeding by the sprocket wheel 6.

However, the rubber platen 1 is connected to the sprocket wheel 6.
If you try to feed a larger amount than the rubber platen 1, the sprocket wheel 6 will brake the feed.
slips on the sliding surface 3 with the drive shaft 2, and its paper feed amount is always the same as the paper feed amount of the sprocket wheel 6.

For this reason, the fanfold paper 5 receives a force from the rubber platen 1 in its feeding direction.

In addition, when driving the recording paper using a sprocket tractor in the above, it is not necessary to make the diameter of the rubber platen 1 larger than the diameter of the sprocket tractor as described above, but it is possible to change the rotation speed to feed the paper by the rubber platen 1. Make sure the quantity is larger.

Furthermore, it goes without saying that the above configuration must satisfy the following conditions.

In other words, the frictional force on the sliding surface 3 between the rubber platen 1 and the drive shaft 2 is T, the force for feeding paper between the rubber platen 1 and the print head is F, the pulling speed of one bow of the fanfold paper 5 is f, and When the number of pins of the sprocket wheel 6 is N, it is necessary to satisfy the relationship fN>T>F.

Next, one embodiment of the present invention will be described with reference to FIGS. 2 and 3.

The paper feeding device shown in FIGS. 2 and 3 is a case in which a rubber platen 1 and a sprocket wheel 6 are integrally combined on the same axis, and the sprocket wheel 6 is rotated by a drive shaft 2. is drive shaft 2
The sprocket wheel rotates by the friction generated by the sliding surface 8 with the side surface of the sprocket foil 6.

Further, the diameter of the rubber platen 1 is larger than the diameter of the sprocket wheel 6.

Therefore, when the fanfold paper 5 is hung as shown in the side view of Fig. 3, the fanfold paper 5 is fed simultaneously by the rubber platen 1 and the sprocket foil 6, but since the diameter of the rubber platen 1 is larger, Attempt to send more amount than sprocket wheel 6.

However, the paper feed on the rubber platen 1 at this time is braked by the sprocket wheel 6, which feeds the paper at a constant speed, so when trying to feed the paper into a strip, the rubber platen 1 slips on the sliding surface 8, and the paper feed on the rubber platen 1 is always controlled by the sprocket wheel 6. Synchronize with paper feed speed of 6.

Therefore, the fanfold paper 5 being fed is always kept stretched by the slippage of the rubber platen 1.

In addition, in the above configuration, as shown in FIG. 4, the print head 4 is pressed onto the rubber platen 1 so as to be located approximately at the center of the contact surface between the rubber roller 1 and the fanfold paper 5, and the pressure of the print head 4 is By forming a friction surface for feeding the paper against the paper, it becomes possible to feed the paper in two directions.

As a result of the above configuration, the present invention provides the following effects.

The present invention brakes excess paper feeding by the rubber platen by accurately feeding the sprocket wheel, and as a result, the rubber platen slips on the sliding surface, and as a result, the paper is always kept taut, preventing the paper from shifting or sagging. Accurate paper feeding is possible without problems such as the fanfold paper not being caught on the pins of the sprocket foil due to an error in the paper feeding speed between the sprocket foil and the rubber platen, and with no meandering of the paper.

It is easy to manufacture since there is no need to provide a complicated mechanism such as lifting the print head during paper feeding.

In addition, by integrating the rubber platen and sprocket foil, it is possible to accurately feed paper in either direction by setting the print head at an appropriate position, making it possible to print in two directions. It has the advantage that it does not run in the opposite direction to the paper feeding direction and can also be used in XY plotters.

In the above description, paper feeding was explained using an example using a sprocket wheel, but the present invention can also be fully implemented using a sprocket tractor 6' in which a sprocket is installed upright on a belt.

FIGS. 5 and 6 are diagrams showing an embodiment using a sprocket tractor 6'.

In this case, a sliding surface 8 that acts as a clutch is located in the middle of the transmission system from the drive motor M to the drive shaft 2 of the rubber platen 1.
All you have to do is set it up.

In addition, reference number 10 in the figure is a gear that distributes and transmits the rotation of the motor M to the rubber platen 1 and the bin tractor 6', 11 is a gear on the drive shaft of the bin tractor 6', and reference number 12 is a gear. This is a timing belt installed between 10° and 11°.

It will be appreciated that in the embodiment shown in Figures 5 and 6, the thermal fanfold paper 5 with perforations engaged by the sprocket tractor can be fed in a horizontal (linear) direction.

[Brief explanation of drawings]

Fig. 1 is a principle diagram showing the principle of the present invention, and is a sectional view of the rubber platen portion, Fig. 2 is a front view of an embodiment of the present invention, and Figs. 3 and 4 are side views of the embodiment of the present invention. 5 and 6 are schematic configuration diagrams of the other side of the present invention. Explanation of symbols, 1...Rubber platen, 2...
... Drive shaft, 3, 8 ... Slip surface, 4 ...
...Print head, 5...Fanfold paper,
6...Sprocket wheel, 6'...
sprocket tractor.

Claims (1)

[Claims] 1. In a paper feeding device for a thermal printer, a platen whose rotation center is the same as the drive shaft through a sliding surface having a predetermined friction is provided, and the thermal recording paper with feed holes is transferred to the print head with a predetermined pressure. A sprocket tractor that feeds paper by pressing it against the platen, and also feeds the paper by rotating between a plurality of axes of the drive shaft and support shaft, which have a smaller paper feed amount than the paper feed of the platen. The excess paper feed amount of the platen is adjusted by sliding the platen on the sliding surface, and the paper feed is performed by synchronizing the paper feed speed of the platen with the paper feed speed of the sprocket tractor. Paper feeding device for thermal printers. 2. Claim 1, characterized in that the print head is located at the center of the contact surface between the platen and the thermal recording paper and the recording paper is fed, thereby making it possible to feed the recording paper in two directions. The paper feeding device for the thermal printer described in Section 1. 3. In a paper feeding device for a thermal printer, a sprocket wheel and a platen whose rotational center line is the same as the drive shaft of the sprocket wheel are provided via a sliding surface having a predetermined friction, and a thermal recording paper with a feed hole is attached to the platen. A print head that presses the heat-sensitive recording paper with a predetermined pressure is provided so as to be located at the center of the contact surface of the platen with the thermal recording paper, and by driving the platen, paper can be fed in two directions. By applying a brake to the paper feed of the platen using the paper feed of the sprocket wheel, which has a smaller diameter and reduces the paper feed amount relative to the paper feed of the platen, the extra feed amount of the paper feed of the platen is reduced by the sliding surface. A paper feeding device for a thermal printer, characterized in that the platen is adjusted by slipping, and the paper feeding speed of the platen is synchronized with the paper feeding speed of the sprocket wheel to perform accurate paper feeding.