JPH0524524Y2 - - Google Patents

Description

[Detailed description of the invention] [Summary] This paper feeding mechanism of a printer is configured so that a plurality of pinch rollers are arranged in parallel on the same axis along the platen, and the paper feeding performance is improved with a simple configuration. Enables stabilization and cost reduction.

[Industrial Application Field] The present invention relates to a paper feeding mechanism for printers that uses a pinch roller pressing method to feed paper by pressing a pinch roller against a platen. The present invention relates to a paper feeding mechanism for a printer that has excellent performance and a small number of parts.

When using a pinch roller pressing method as a paper feeding mechanism in a printer, two or more rollers are installed at mutually dispersed positions in the longitudinal direction of the platen, depending on the length of the printer, the width of the paper, etc. It is necessary to arrange pinch rollers such that these pinch rollers elastically press the paper against the platen, and to have a structure that allows these pinch rollers to be retracted from the platen when continuous paper is used.

In such a structure, it is necessary to make the paper feed highly accurate, and in order to reduce the cost of the printer, it is necessary to reduce the number of parts of the mechanism that elastically supports these pinch rollers. It is requested.

[Conventional technology]

Conventionally, as a paper feeding mechanism for a printer using the pinch roller pressing method, a square shaft 2 is provided in a position parallel to the platen 1 as shown in FIGS. By fitting the square hole 4 at the base of the leaf spring 3 to the square shaft 2 at a plurality of positions, for example, two positions, each leaf spring 3 is attached to the square shaft 2 so as to be non-rotatable relative to the square shaft 2.

A bracket 7 bent into a U-shape is attached to the free end 5 of the leaf spring 3 via the central axis 6.
Attached so that it can rotate relative to the

Pinch rollers 9 are rotatably attached to both ends 8 of the bracket 7.

The square shaft 2 can be rotated and fixed by the operator within the phase angle indicated by the arrow 10 in FIG.

The phase relationship between the platen 1, the square shaft 2, and the pinch rollers 9 is such that when the square shaft 2 takes a phase 11 in which the square shaft 2 rotates clockwise due to such an operation, each pinch roller 9 is rotated in the direction of the arrow by the leaf spring 3. It is biased in the direction of 13 and assumes a pressed state against the platen 1. Further, when the square shaft 2 takes a phase 12 in which it rotates counterclockwise, each pinch roller 9 is in a released state.

In a printer equipped with this conventional paper feeding mechanism, when using a cut sheet, the pinch roller 9 is pressed, the paper 14 is pressed between the platen 1 and the pinch roller 9, and the rotation of the platen 1 causes the paper to be cut. can be sent.

Note that when continuous paper is used in this printer, the pinch roller paper is released so that the pinch roller 9 does not interfere with the feeding of the continuous paper by a tractor (not shown) or the like.

[Problem that the invention attempts to solve]

In this conventional method, the leaf spring 3 and the bracket 7 must be provided at each of the plurality of positions along the platen 1 where the pinch roller 9 is to be provided, so the number of parts is large, and the number of assembly steps increases. There is a problem that the cost of the printer increases.

In addition, in this structure, the pinch rollers 9 are attached to the square shaft 2 at each position using different leaf springs 3. It can be installed in an uneven state.

To explain this with reference to FIG. 6, if there are variations in the length accuracy of the leaf springs 3, the platen 1
The position x of the pinch roller 9 in the direction along the circumference of the outer peripheral surface causes a variation of Δx. Furthermore, if there is variation in the positional accuracy of the attachment of the leaf spring 3 to the square shaft 2, the pitch p of the pinch roller 9 in the longitudinal direction of the platen 1 will vary by Δp.

If the positions of the pinch rollers 9 vary in this way, each pinch roller 9 with respect to the platen 1
There are also variations in the pressing pressure. the result,
There are problems in that the feeding system becomes uneven, such as the paper 14 being skewed and errors in the line feed pitch.

The present invention has been created in view of these points, and aims to provide a paper feeding mechanism for a printer that is simple in structure and capable of reducing printer costs and stabilizing paper feeding performance.

[Means for solving problems]

In the paper feeding mechanism of the printer of the present invention, the square shaft can be fixed at a plurality of phase angles by selecting one.

A plurality of support plates are rotatably attached to the square shaft.

A center shaft is attached to the protrusion of the support plate, and a plurality of brackets are attached to the center shaft so as to be rotatable relative to the support plate.

A shaft is attached to each of the protrusions of the bracket, and a plurality of pinch rollers are arranged in parallel on the shaft so as to be rotatable relative to the bracket.

A leaf spring is mounted relatively non-rotatably on the square shaft, and the free end of the leaf spring biases the central shaft toward the platen.

[Effect]

The paper feeding mechanism of the printer of the present invention allows multiple pinch rollers to be arranged in the longitudinal direction of the platen to be arranged in parallel on a common shaft.
These pinch rollers are integrally held on the square shaft by a bracket, a central shaft, and a support plate. Therefore, compared to the conventional pinch roller holding method explained above based on FIGS. 4 and 5, which is a split type, a large number of pinch rollers are held on a square shaft by a small number of parts. obtain. Therefore, it is possible to reduce the cost of the printer by reducing manufacturing costs and assembly man-hours.

In addition, the paper feeding mechanism of the printer of the present invention has multiple pinch rollers arranged in parallel on the shaft.
The positions of these pinch rollers are determined by common members such as brackets and support plates. Therefore, compared to the conventional split type, there is no variation in the position of each pinch roller due to variations in component accuracy, and the pressing pressure of the pinch rollers against the platen is uniform. Therefore, it is possible to prevent skewing of paper during paper feeding and improve line feed accuracy.
As a result, feeding accuracy is improved.

In addition, since the support plate as a means for holding the pinch roller on the square shaft and the leaf spring as a means for biasing the pinch roller against the platen are separated, uneven contact of the pinch roller due to twisting of the leaf spring etc. There is no risk of non-uniformity of pressing pressure, and feeding accuracy can be further improved.

〔Example〕

1 to 3 show examples of the present invention, in which FIG. 1 is a perspective view, FIG. 2 is a sectional view taken along line A-A in FIG. 1, and FIG. 3 is a cross-sectional view of FIG. It is a sectional view along the BB line.

In the figure, a square shaft 2 is provided at a position parallel to the platen 1.

The support plate 20 can be rotated relative to the square shaft 2 by fitting round holes 21 provided at the bases of a pair of lever-shaped support plates 20 to the square shaft 2. It is attached to.

Both support plates 2 are provided at the free end 22 of the support plate 20.
The vicinity of the end of the central shaft 23 extending between 0 and 0 is rotatably supported.

A pair of brackets 24 forming U-shaped bearings are attached to the central shaft 23 at approximately the center thereof.

Each of the protrusions 25 of the bracket 24 has a shaft 26 extending between the brackets 24.
The vicinity of the end is rotatably supported.

A plurality of pinch rollers 9 are arranged in parallel at mutually dispersed positions on each shaft 26, and the pinch rollers 9 are fixed to the shaft 26.

Furthermore, the square shaft 2 is fitted with a square hole 28 at the base of the leaf spring 27 at an approximately intermediate position between the pair of support plates 20, so that the leaf spring 27 can be attached to the square shaft 2. It is fixed.

A substantially central portion of the central shaft 23 is placed in contact with the free end 29 of the leaf spring 27 .

The square shaft 2 can be rotated and fixed by the operator within the phase angle indicated by the arrow 30 in FIG.

The positional relationship between the platen 1, the square shaft 2, and the pinch rollers 9 is such that when the square shaft 2 takes a phase 31 in which the square shaft 2 rotates clockwise due to such an operation, each pinch roller 9 rotates through the central shaft 23. The platen 1 is biased in the direction of the arrow 33 by the leaf spring 27, and is pressed against the platen 1. Further, when the square shaft 2 takes a phase 32 in which it rotates counterclockwise, each pinch roller 9 is in a released state.

When using a cut sheet in a printer equipped with a paper feed mechanism of such a structure, the pinch roller 9 is pressed and the paper 14 is
Each member determines the position of the pinch roller 9 when the pinch roller 9 is pressed against the platen 1.
Pinch roller 9
There is no variation in the position of the pinch roller 9, and the pressing pressure of the pinch roller 9 is uniform.

If the pressing pressure of the plurality of pinch rollers 9 arranged in parallel becomes uneven for some reason, one or both of the pair of support plates 20 may become attached to the square shaft 2.
By rotating the pinch roller 9 relative to the platen 1 and correcting the positional relationship of the pinch roller 9 with respect to the platen 1, uniformity of the pressing pressure is restored.

In particular, since all the pinch rollers 9 only rest by gravity on the free end 29 of the leaf spring 27 via the central axis 23, each pinch roller 9 follows the movement of the leaf spring 27. It can be moved up and down. Therefore, as described above, the pinch roller 9
The function of keeping the pressing pressure uniform is almost unaffected by the accuracy of the leaf spring 27 parts.

Since the pressing pressure of the pinch roller 9 is uniform in this way, stable paper feeding performance is achieved, such as no skewed feeding of the paper and excellent line feed accuracy.

Further, as means for holding the plurality of pinch rollers 9 to be arranged in the longitudinal direction of the platen 1 on the square shaft 2, a support plate 20, a central shaft 23, a bracket 24, a shaft 26, and each pinch roller 9 are biased toward the platen 1. Since the leaf spring 27 is common to all the plurality of pinch rollers 9, it contributes to a reduction in the number of parts and cost.

[Effect of idea]

As described above, according to the present invention, it is possible to reduce costs by reducing the number of parts and stabilize paper feeding with a simple configuration, and is extremely useful in practice.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing an embodiment of the present invention, Figure 2 is a sectional view taken along line A-A in Figure 1, and Figure 3 is B in Figure 1.
-B sectional view, Figure 4 is a perspective view of the conventional structure, Figure 5 is a perspective view of the conventional structure.
The figure is a side view of the conventional structure, and FIG. 6 is an explanatory diagram showing variations in the position of the pinch roller in the conventional structure. 1 to 3, 1 is a platen, 2 is a square shaft, 9 is a pinch roller, 20 is a support plate, 22 is a protrusion of the support plate, 23 is a central shaft, 24
is the bracket, 25 is the protrusion of the bracket, 26
is a shaft, 27 is a leaf spring, and 29 is a free end of the leaf spring.

Claims (1)

[Claims for Utility Model Registration] A square shaft 2 that can be fixed by selecting a plurality of phase angles, a plurality of support plates 20 that are rotatably attached to the square shaft 2, and a protrusion of the support plates 20. a central shaft 23 attached to the support plate 22; a plurality of brackets 24 attached to the central shaft 23 so as to be rotatable relative to the support plate 20 about the central axis 23; A shaft 26 attached to each of the protrusions 25, and a bracket 24 centered around the shaft 26.
a plurality of pinch rollers 9 arranged in parallel on the shaft 26 so as to be rotatable relative to the shaft 26;
and a leaf spring 27, one end of which is fixed so as not to rotate relative to the square shaft 2, and a free end 29 which biases the center shaft 23 toward the platen 1. The printer's paper feed mechanism.