JPH0120127Y2 - - Google Patents

Description

[Detailed explanation of the idea] Technical field of invention This invention relates to a paper feeding device for a printing machine.

Technical background of the invention and its problems Conventionally, there has been a device in which a tractor is provided below the platen, and the sprocket paper sent from the tractor is sent out by rotation of the platen after printing. In this case, the tractor and platen are rotated synchronously, and the outer diameter of the platen is determined so that the sprocket paper does not slacken between the platen and the tractor and cause a jam. It is designed to be slightly larger in quantity. However, the sprocket paper may slip against the platen, and due to differences in the number of sheets of sprocket paper to be printed on, differences in paper quality, differences in the binding condition, etc., the diameter of the sprocket paper wrapped around the platen changes slightly, resulting in continuous paper slipping. When feeding, variations in feed amount due to the platen accumulate. This causes a problem in that the printing position is misaligned and multiple sprockets stacked one on top of the other may peel off from each other.

Purpose of the invention This invention was developed in view of the above-mentioned points, and the object is to provide a paper feeding device for a printing machine that can always accurately maintain the feeding pitch of the sprocket paper.

Summary of the invention This invention has a first tractor placed at the bottom of the platen and a second tractor placed above the platen, so that the sprocket paper fed from the first tractor is always kept constant by the second tractor. Therefore, it is possible to prevent misalignment of the printing position, etc., and when setting the sprocket paper on the first tractor and then setting it on the second tractor, The structure is such that only the drive shaft of the second tractor can be manually rotated to align the paper feeding protrusion of the second tractor with the feeding hole of the sprocket paper.

Embodiment of the invention An embodiment of the invention will be described based on the drawings.
A platen 2, a carrier shaft 3, and a guide shaft 4 are installed on opposing side frames 1, and a carrier 6 carrying a dot printer head 5, which is a printing section, is slidably held by the carrier shaft 3 and guide shaft 4. There is. A pinch roller 7 and a paper bail roller 8 are provided on the outer periphery of the platen 2 so as to be able to move toward and away from each other. Also, below the platen 2 are two paper feed paths 9 and 1.
0 is provided, and a first tractor 11 is provided below one paper feed path 9. This first tractor 11 has a pair of left and right tractor bodies 14 slidably fitted to a drive shaft 12 and a guide 13.
A drive wheel (not shown) driven by the drive shaft 12 and a belt (not shown) partially wound around the drive wheel are attached to these tractor bodies 14. A large number of protrusions 15 are formed.

Furthermore, a second tractor 16 is provided above the platen 2. This second tractor 16
A pair of left and right tractor bodies 19 are slidably fitted to a drive shaft 17 and a guide 18, and a sprocket 21 having a large number of protrusions 20 is attached to these tractor bodies 19 while being connected to the drive shaft 17. .

A platen gear 23 and a pulley 24 driven by a motor (not shown) are fixed to one end of the shaft 22 of the platen 2, and a pulley 24 and a pulley 24 fixed to one end of the drive shaft 12 of the first tractor 11 A timing belt 26 is wound around 25 and 25. Further, a platen gear 2 is connected to one end of the drive shaft 17 of the first tractor 16 via an idler gear 27.
A tractor gear 28, which is a rotating body connected to 3, is rotatably fitted. That is, the tractor gear 28 is connected to the motor via a gear mechanism including an idler gear 27 and a tractor gear 23. Further, a dial 29 is fitted to one end of the drive shaft 17 so as to be slidably biased toward the tractor gear 23 by a spring 30. A boss 31 protruding from the side surface of this dial 29 has a groove 33 that engages with a pin 32 driven into the drive shaft 17.
This pin 32 prevents relative rotational movement between the dial 29 and the drive shaft 17.

Therefore, the boss 3 formed on the tractor gear 28
A spring clutch 36, which is a one-way clutch, is formed by winding a coil spring 35 around a boss 31 formed on the dial 29 and a boss 31 formed on the dial 29. This spring clutch 36 transmits only the clockwise rotation of the tractor gear 28 to the drive shaft 17 in FIG. and,
A plate 37 that holds both ends of the drive shaft 17 and guide 18 is provided with a hook 39 supported by a bearing 38 of the platen 2 and a pin 41 supported by a U-shaped groove 40 of the side frame 1.

In such a configuration, the sprocket paper 4
When the platen 2 is set on the first and second tractors 11 and 16 and the platen 2 is rotated clockwise by the motor, this rotation is caused by the timing belt 26 on the one hand.
is transmitted to the drive shaft 12 from the first tractor 11
feeds the sprocket paper 42 towards the dot printer head 5, while the idler gear 2
7. Tractor gear 28, spring clutch 36
The first tractor 16 pulls out the sprocket paper 42 upward.
The paper feed amounts of the first and second tractors 11 and 16 are the same. As a result, the sprocket paper 42
Even if the number of sheets or paper quality changes or the sprocket paper 42 slips against the platen 2, the feeding pitch of the sprocket paper 42 remains constant.
This makes it possible to reliably prevent misalignment of the printing position.

When the sprocket paper 42 is first set on the first tractor 11 and then set on the second tractor 16, if the protrusion 20 of the sprocket 21 of the second tractor 16 does not fit into the feed hole of the sprocket paper 42, By connecting the tractor gear 28 and the drive shaft 17 with the spring clutch 36, the drive shaft 17 can be rotated together with the sprocket 21 by gripping the dial 29. Therefore, the protrusion 20 of the sprocket 21 can be engaged with the feed hole of the sprocket paper 42 without loosening the sprocket paper 42 between the platen 2 and the second tractor 16.

In addition, the motor is reversed to rotate the sprocket paper 42.
Even when printing is performed by reversing downward by the first and second tractors 11 and 16, no deviation in feed pitch occurs. Also, the sprocket paper 42 inserted into the paper feed path 9 is pulled out by the second tractor 16 and printed on it, and furthermore, the other recording paper inserted into the paper feed path 9 is fed by the platen 2 and the pinch roller 7 and printed. You are free to do whatever you want. Since the second tractor 16 is held by the plate 37 and formed into a unit, it can be removed with a single touch.

Effects of the invention Since this invention is configured as described above, when the first tractor sends the sprocket paper to the printing section and prints, the sprocket paper can be pulled out from the printing section by the second tractor, and therefore, the sprocket paper can be pulled out from the printing section by the second tractor. By rotating the first and second tractors synchronously, the feed pitch of the sprocket paper can be maintained constant, thereby reliably preventing misalignment of the printing position, and furthermore, the drive shaft and motor of the second tractor By connecting the rotating body connected to the first tractor with a one-way clutch, the drive shaft of the second tractor can be independently rotated in accordance with the sprocket paper set on the first tractor, and therefore the two Even if a tractor is provided, the sprocket paper can be easily set without loosening it.

[Brief explanation of the drawing]

The drawing shows one embodiment of this invention.
The figure is a side view, FIG. 2 is a partial perspective view showing a power transmission structure to a second tractor, and FIG. 3 is a sectional view showing a connection structure using a spring clutch. 2... Platen, 5... Dot printer head (printing part), 6... Carrier, 11... First tractor, 12... Drive shaft, 16... Second tractor, 17... Drive shaft, 28... ...Tractor gear (rotating body), 36...Spring clutch (one-way clutch).

Claims (1)

[Scope of utility model registration request] A carrier on which a printing section is mounted is provided to be able to slide freely along the platen, a first tractor is arranged below the platen, a drive shaft of the first tractor and the platen are connected to a motor, and the platen is A second tractor is removably attached to the upper part of the second tractor, and a rotating body is attached to the motor via a gear mechanism that meshes with the second tractor on the axis of the drive shaft of the second tractor. A paper feeding device for a printing machine, characterized in that a one-way clutch is provided between the rotating body and the drive shaft of the second tractor for transmitting the driving force from the rotating body only in the direction in which the sprocket paper is fed.