JPS587471B2 - Sprocket pin mounting structure - Google Patents

Description

[Detailed Description of the Invention] The present invention allows characters, symbols, etc. to be selectively printed or printed using pixels, etc., and can be used with both plain paper and marginal punched printing paper with a simple switching operation. This paper pertains to a printer's paper feeding mechanism.

Conventionally, the paper feed mechanism of a printer that can be used for both plain paper (as shown in Figure 7) and marginal punched printing paper (as shown in Figure 8) with a simple switching operation is shown in Figure 1, to give an example. As shown in FIG.
A presser roller 103 is placed in pressure contact with the printing paper 10.
9 was guided to the platen 108 by a paper guide (inner) 106 and a paper guide (outer) 107.

The sprocket 104 had a pin 104-1 inserted into a holding member 104-2 and a hole bored therein, and was supported within the hole by a spring.

When printing paper with a marginal punch is used, the presser roller 103 is separated from the friction row 2102, and the marginal punch is fed into engagement with the pin 104-1.

When plain paper is used, the presser roller 103 is brought into pressure contact with the friction roller 102 with the plain paper 109 sandwiched therebetween, and is fed by the frictional force as the friction roller 102 rotates.

At this time, the pin 104-1 was pushed in the axial direction by the rigidity of the plain paper and pulled into the hole of the holding member 104-2 against the force of the spring, so there was no problem in feeding the plain paper.

However, as can be inferred from the above explanation, the spring force cannot be made large, so when feeding printing paper with marginal punches, there may be a misalignment at the start of engagement between the marginal punch and the pin 104-1, or the printing paper with marginal punches may overlap. If the pin 104-1 and the marginal punch do not engage, the pin 104-1 and the marginal punch do not engage due to reasons such as the actual opening of the punch becoming narrower due to mutual punch position deviation.
4-1 would retract, causing feeding errors, or worse, causing jamming in the paper guide, which was not sufficient.

In order to overcome this drawback, it is necessary to create a structure in which the pin 104-1 does not retract, that is, a fixed pin structure.

If a completely fixed pin is used, it is difficult to switch to plain paper feeding, so the pin 1041 needs to have a structure that can be easily pulled out or implanted.

A first object of the present invention is to provide a sprocket with a pin structure that can be easily inserted and removed.

In addition, in printing machines that feed paper using sprockets, there is a certain distance from the sprocket position to the printing position, and if the printing position is predetermined by ruled lines etc. on the marginal punched printing paper, it is difficult to find the correct position. The angular position of the sprocket must be adjusted during assembly to ensure printing.

In many cases, an intermittent feed mechanism and a sprocket 1 are used, as shown by the ratchet wheel 110 as a representative example in FIG.
A method is adopted in which the relative angular position of 04 is adjusted.

There is no problem if the angular position of the intermittent feeding mechanism can be adjusted, but if this is not possible due to space constraints, the angular position of the intermittent feeding mechanism is completely fixed within a certain degree of variation, and the sprocket 104 You will have to adjust the .

Conventionally, as shown in FIG. 1, a set screw 10 is attached to a round shaft 101.
5, and the sprocket 104 was adjusted in an analog manner by loosening the set screw 105.

At this time, if you use printing paper with marginal punches on only one side of the paper, it is still easy to adjust since there is only one tin rocket, but if you use printing paper with marginal punches on both sides, it is easier to adjust. In this case, it is necessary to align the phases with respect to each other's sprocket pins 104-1 and to adjust the distance from the sprocket to the printing position (angular position adjustment), which requires a lot of effort.

A second object of the present invention is to provide a sprocket device having a structure that allows the above-mentioned adjustment to be made using a very simple digital method.

Embodiments of the paper feeding mechanism according to the present invention will be described below with reference to the drawings.

FIG. 2 is a sectional view of the paper feeding mechanism according to the present invention, and FIG. 3 is an external view thereof.

Reference numeral 21 denotes a paper feed shaft, which is made up of a round shaft portion 21-1 and a square shaft portion 21-2.

A holding member 2 that holds four pins 22 is provided on the round shaft portion 21-1.
3 are rotatably fitted.

An adjustment member 24 is fitted into the square shaft portion 21-2 so as to be slidable in the axial direction of the paper feed shaft 21, and a plurality of grooves 24-1 provided in the adjustment member 24 and a plurality of grooves 24-1 provided in the holding member 23 are fitted. protrusion 23-
1 engages, and in order to ensure this engagement, the paper feed shaft 21
A coil spring 26 whose one end is locked to a plain paper feeding friction roller 25 fixed to is provided.

An end surface 23 - 2 of the holding member 23 is engaged with an E-shaped retaining ring 27 .

FIG. 4 is a diagram showing a state in which the pin 22 and the holding member 23 are connected.

The pin 22 is molded from plastic and has two flexible legs 22-2, a recess 22-1, and a collar 22-4.

The holding member 23 has a recess 23-8 into which the pin 22 is inserted, as shown in the plan view of the holding member in FIG. 5, and a cross section of the recess 23-8 is shown in FIG. 23
-8 is provided with a flesh portion 23-3' having an opening 23-9 at the bottom and having a substantially trapezoidal cross-sectional shape.

To insert the pin 22 into the holding member 23, slide the foot 22-2 on the slope 23-4 of the meat part 23-3.
Push it in the direction of arrow A to open it.

When the pin 22 is pushed in until the surface 22-5 of the collar 22-4 is locked with the locking surface 23-7 of the holding member, the foot 22-2
The tip of the foot leaves the slope 23-4 and falls toward the opening 23-9 due to the flexibility of the foot 22-2, and the surface 23-5 and the surface 22
-3 is in pressure contact and the pin 22 is fixed to the holding member 23.

At this time, in order to maintain the posture of the pin 22, the end surface 23-10 of the recess 23-8 is aligned with the pin 2 in the direction of rotation of the sprocket.
A convex portion 23-11 provided on the meat portion 23-3 guides the side surface of the leg 22-2 of
By fitting the recess 22-1 provided in the pin 22 and contacting the surface 22-5 and the surface 23-7, the pin 22
is prevented from falling over.

When removing the pin 22, it can be easily removed by holding the outer surface of the collar 22-4 with a tool and pulling it in the direction opposite to the arrow A direction.

At that time, the end of the collar 22-4 protrudes from the end surface 23-6 of the holding member 23 so that it can be easily pinched.

Next, a mechanism for adjusting printing so that it is printed at a predetermined location on the marginal punched printing paper will be explained.

In this embodiment, as shown in FIGS. 2 and 3, the paper feed shaft 2 is
1, a ratchet wheel 28 as an intermittent driven member is fixed in the rotational direction by a spring pin 29.

This fixing method may be any other method.

Although not shown, the ratchet wheel 28 is intermittently rotated by a certain angle each time one line is printed to a certain angular position determined by the reciprocating movement of the pawl.

This angular displacement is transmitted to the pin 22 by the paper feed shaft 21, the adjustment member 24, and the holding member 23.

The pin 22 and the marginal punch are engaged, and the printing paper with the marginal punch is guided by a paper guide (not shown but provided in the same manner as in FIG. 1) and guided to the printing section.

In other words, the printing position and the sprocket (pin 22 and holding member 2)
The rotation angle positions in 3) have a one-to-one correspondence.

At the printer design stage, the rotational angular position of the sprocket is optimally designed, but in the manufactured printer, the actual printing position varies to some extent due to variations due to tolerances of valley parts, assembly variations, etc.

Therefore, in this embodiment, the above-mentioned variations are absorbed by adjusting the angular position of the holding member 230 with respect to the adjusting member 24 (or ratchet wheel 28).

That is, the adjustment member 24 is provided with a plurality of grooves 24-1.

Specifically, as shown in FIG. 6, which is a plan view of the adjustment member 24 seen from the groove 24-1 side, five tapered grooves 24-1a are formed.
24-1e are provided at certain angles θ.

In the first assembly stage, the holding member 23 is assembled so that the tapered protrusion 23-1 engages with the groove 24-1c (the printing position is designed to be optimal at this time).

In addition, the ratchet wheel 28 has n teeth.
It is assumed that the pins 22 are fed one tooth at a time by the reciprocating motion of the claws, and that the number of pins 22 is m, which are connected to the holding member 23 in equal parts.

It is also assumed that the ratchet wheel 28 is rotated clockwise when viewed from the direction of arrow B in FIG. 2 by a pawl.

For example, changing the engagement between the groove 24-1c and the protrusion 23-1 to the engagement between the groove 24-1b and the protrusion 23-1 is achieved by moving the adjusting member 24 as shown in the arrow. This results in rotation by an angle θ clockwise when viewed from direction B.

Now, since the adjustment member 24 and the ratchet wheel 28 can be considered as one body, the ratchet wheel 28 also moves clockwise at an angle θ.
You will be forced to rotate it.

On the other hand, since the number of teeth of the ratchet wheel 28 is n, the pitch angle of the teeth is 2π/n, so as a result, the rotation angle of the ratchet wheel 28 is Φ = θ - the amount of filter paper feed when the next steady paper is In the feeding state, the printing paper is being pulled back.

The reason for this is that the dead center of the pawl that drives the ratchet wheel 28 intermittently remains unchanged.

In other words, the printing position is shifted from when the groove 24-1c and the protrusion 23-1 engage with each other by a paper feed amount corresponding to the rotation angle Φ of the ratchet wheel 28 in the direction in which the printing paper travels.

When actually applying numerical values to the embodiments of the present invention, Φ
=0.026 radian.

Now, assuming that the radius of the pin 22 at the position where it engages with the marginal punch is approximately 8 mm (assuming that it is m-4 and the pitch of the marginal punch is 12.7 mm), the paper feed amount corresponding to Φ is 8Φ and 0.21 mm. becomes.

In other words, the printing position can be shifted by 0.21 mm by moving the engaging groove of the protrusion 23-1 from 24-1c to the adjacent one, and in the case of this embodiment, the printing position can be shifted in two steps before and after the initial printing position. It can be adjusted by 0.42mm, and the range can be adjusted by 0.84mm.

The adjusting member 24 may be provided with a portion corresponding to the protrusion 23-1, and the holding member 23 may be provided with a portion corresponding to the grooves 24-1a to 24-1e.

Further, the adjusting member 24 is connected to the holding member 23 by the air spring 2.
6, the tapered groove 24-1
The protrusions 23-1 and 23-1 are tightly interlocked, and when shifting the engagement to the adjacent position, the adjustment member 24 is actually slid toward the friction roller 25 side against the force of the coil spring 26, and the grooves 24-1 and the protrusions are After the sprocket 23-1 is disengaged, the sprocket is moved to a position where it can engage with the adjacent groove 24-1, and by releasing the force that was resisting the coil spring 26, the sprocket can be easily engaged with the adjacent groove. .

In particular, although the illustrations of the embodiment show a sprocket on one side, the most advantageous alternative embodiment is the friction roller 25.
Since the fitting shaft portions of the left and right adjustment members 24 are square, there is no phase in the left and right angular directions, making adjustment very easy.

As explained above, one is that by using a pin that can be inserted and removed by utilizing its own flexibility, it is possible to easily switch between a fixed pin for printing paper with marginal punch and a paper feed type printer and a printer for plain paper. In addition, since the embodiment adopts a format in which the holding member 23 is sandwiched between two legs 22-2, when the holding member 23 is manufactured by plastic molding, a mold that is punched in two directions is sufficient. There are uses such as being cheaper.

Further, flexibility may be imparted to the holding member 23 instead of to the pin 22.

Second, check the misalignment of the printing position in advance.
Providing a mechanism that can easily adjust the amount closest to the equivalent amount by digitally changing the engagement position of the protrusion and groove will greatly contribute to cost savings in the actual manufacturing process. It is.

This adjustment method can also be applied to the ratchet wheel 28, and is not limited to the paper feeding mechanism of this embodiment.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a paper feeding mechanism of a printer that can use both conventional plain paper and marginal punched printing paper by a switching operation. FIGS. 2 to 6 show embodiments of the present invention, and FIG.
The figure is a sectional view of the paper feed mechanism, Figure 3 is an external view of the paper feed mechanism, Figure 4 is a diagram showing the state of connection between the pin and the holding member, Figure 5 is a plan view of the holding member, and Figure 6 is a plan view of the adjustment member. be. FIG. 7 shows plain paper, and FIG. 8 shows printing paper with marginal punches on both sides. 21...Paper feed shaft, 22...Pin, 2
3... Holding member, 23-1... Protrusion,
24...adjustment member, 24-1...groove,
25...Friction roller, 26...Coil spring, 27...E type retaining ring, 28...
Ratchet wheel (intermittently driven member), 29...
···spring pin.

Claims (1)

[Scope of Claims] 1. In a structure in which the sprocket pin is attached to a holding member that holds the sprocket pin, two legs having hook-shaped tips and having elasticity are provided facing each other, and the tip is provided at the center between the legs. a sprocket pin integrally molded of plastic with a concave or convex portion on the top; a substantially trapezoidal flesh portion having a convex or concave portion on the top that engages with the concave or convex portion; and a flesh portion on the bottom of the flesh portion. a holding member having an insertion hole that communicates with the provided opening and into which the foot of the sprocket pin is inserted, and the foot of the sprocket pin is inserted while being bent along the internal slope of the trapezoidal shape. Then, the concave or convex portion of the sprocket pin is engaged with the convex or concave portion provided in the flesh portion for positioning, and further, the tip of the foot of the sprocket pin is engaged with the opening, and the sprocket pin is positioned. The sprocket pin mounting structure has a structure in which the sprocket pin is attached to the holding member by inserting the flesh part with your feet.