JPH0135746B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an improvement in a printing device that uses continuous paper, and in particular to a printing device that adjusts the gap between paper feed rollers to prevent damage to the printing paper. It is related to the device.

2. Description of the Related Art In general, printing paper used in printing devices as output devices such as computers is generally continuous paper having perforations formed at predetermined intervals.

[Conventional technology]

Conventional printing devices that use such continuous paper,
For example, a schematic configuration diagram of an electrostatic printing device is shown in FIG. In the figure, 1 is a hopper that stores the continuous paper 2, 3 is a transfer drum that transfers the electrostatic latent image onto the continuous paper 2, 4 is a transfer section, 5 is a tractor that drives the continuous paper, and 6 is a transfer drum that transfers the electrostatic latent image onto the continuous paper 2. A fixing unit 7 fixes the transferred output information, and 7 is the continuous paper 2
A paper feed roller 8 is a stacker that folds and stacks the printed continuous paper 2.

In such a configuration, the continuous paper 2 stored in the hopper 1 is moved by the paper feeding tractor 5 and comes into contact with the transfer drum 3 on which a latent image of output information from a computer or the like is printed. In the transfer section 4, the powder toner adhering to the electrostatic latent image on the transfer drum 3 is transferred. After that, the continuous paper 2 to which the powder toner is heat-sealed in the fixing unit 6
are sent to the stacker 8 by a plurality of pairs of paper feed rollers 7, and are sequentially stacked while being folded.

Since the circumferential speed of the paper feed roller 7 that feeds the continuous paper 2 into the stacker 8 is set to be faster than the feed speed of the tractor 5, the driving side roller of the paper feed roller 7 contacts the continuous paper 2 in a slip state. The roller rotates while applying tension to the continuous paper 2 fed from the tractor 5. As a result, the fixing section 6
The continuous paper 2 is not sagged while it is being conveyed, and a good fixing process can be performed.

On the other hand, in this printing device, the feed speed of the tractor 5 at the start of the printing operation can be changed instantly to the transfer drum 5.
Because it is difficult to match the circumferential speed of the continuous paper 2 due to the physical characteristics of the rotational drive system,
The perforations are shifted (slack) by a certain amount toward the hopper 1 side of the transfer section 4. In other words, the paper feed tractor 5 is switched to reverse direction drive using the signal at the time when the printing device finishes printing the last line, and the continuous paper 2 is caused to travel a certain amount in the reverse direction to return to the initial state. There is.

[Problem to be solved by the invention]

However, when the continuous paper 2 runs backwards, that is, during backfeed, the continuous paper 2 is touched by the tractor 5 between the paper feed roller 7 and the tractor 5.
When the continuous paper 2 starts to be fed in the reverse direction, extra tension due to the acceleration is applied, causing problems such as damage to the feed holes of the continuous paper 2 and breakage of the perforations at the pin portion of the tractor 5. Further, there was a problem in that the output information of the powder toner thermally fused to the continuous paper 2 by the driven roller 12 due to the contact state was contaminated.

The present invention has been made to solve the above-mentioned problems, and reduces the tension applied to continuous paper by adjusting the gap between the driving side roller and the driven side roller of the paper feed roller when continuous paper runs in reverse. The object of the present invention is to provide a printing device that can perform the following operations.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a paper feed tractor 5 that causes the continuous paper 2 to travel in the forward or reverse direction in the transfer section 4, and a paper feed tractor 5 that transports the continuous paper fixed in the fixing section 6 to the stacker 8 in a sandwiched state. The printing device is equipped with at least a pair of paper feed rollers 10 consisting of a driving roller 11 and a driven roller 12, and when the paper feed tractor 5 moves the continuous paper 2 in the forward direction, the paper feed tractor The driving roller 11 of the paper feed roller 10, which has a circumferential speed faster than the feed speed of 5, rotates in contact with the continuous paper in a slip state, and stacks the continuous paper fed by the paper feed tractor while applying tension. side, and when the paper feed tractor 5 causes the continuous paper 2 to travel in the opposite direction, the driven roller 12 of the paper feed roller is driven by the support lever 13 so as to be separated from the continuous paper. It is characterized by the fact that

[Effect]

In an initial state in which the continuous sheet of paper is traveling a certain distance in the reverse direction by the paper feed tractor, when the driven roller of the paper feed roller is separated from the continuous sheet of paper via a support lever that is activated at that time, for example driven by an electromagnet, The forward paper feeding action by the driving roller is eliminated, and therefore the extra tension on the continuous paper between the paper feeding roller and the paper feeding tractor is eliminated. Therefore, there is no problem of the continuous paper being damaged by the pin portion of the paper feed tractor.

〔Example〕

FIG. 2 is a schematic configuration diagram for explaining one embodiment of the present invention. In Fig. 2, the printing device of the present invention is composed of continuous paper, a transfer drum, a tractor, a fixing section, a paper feed roller, etc., as in the conventional example shown in Fig. 1, and the structure of the paper feed roller has been improved. It has characteristics. Therefore, except for the paper feed roller, the same symbols as in Fig. 1 are given.
To avoid duplication, explanations regarding these parts will be omitted here.

Particularly, the driven roller 12 of the paper feed roller 10 that characterizes the present invention is attached to one end of a support lever 13 rotatably supported on a fulcrum 14, and is attached to the other end of the support lever 13. The driven roller 1
2, a tension spring 15 is provided for pressing the continuous paper 2 against the driving roller 11. An electromagnet 16 is disposed at the other end of the lever 13 on the opposite side of the tension spring 15.

After printing the last line of the desired information, the continuous paper 2
When backfeeding a certain amount of , by energizing the electromagnet 16 prior to the operation, the support lever 13 made of a magnetic material attracted to the electromagnet 16 against the spring 15 moves around the fulcrum 14. Rotates to separate the driven roller 12 from the driving roller 11. As a result, no extra tension is applied to the continuous paper 2 between the paper feed roller and the tractor, so that subsequent backfeeding of the paper by the tractor in the reverse direction is performed smoothly.

When the electromagnet 16 is de-energized after backfeeding a certain amount of the continuous paper 2 in this way, the support lever 13 returns to its normal printable state due to the tensile force of the spring 15.
The driven roller 12 is brought into pressure contact with the driving roller 11 to sandwich the continuous paper 2.

Although this embodiment has been described for backfeeding the continuous paper 2, the present invention can be applied not only to backfeeding but also to setting the starting edge of continuous paper. Further, in a printing device having a plurality of paper feed rollers, it is preferable to apply the gap adjustment to all of the paper feed rollers, but it may also be applied to some of the rollers. A mechanical rotation method or the like may be used.

〔Effect of the invention〕

As is clear from the above description, the printing device according to the present invention has the advantage of being able to prevent continuous paper from being damaged and smeared, and also reducing the load on the tractor drive motor, contributing to quality improvement and continuous printing. This is extremely advantageous when applied to various printing devices that use paper.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram for explaining a conventional printing apparatus, and FIG. 2 is a schematic block diagram for explaining a printing apparatus according to the present invention. In the figure, 1 is a hopper, 2 is a continuous sheet of paper, 3 is a transfer drum, 4 is a transfer section, 5 is a tractor, 6 is a fixing section, 7 and 10 are paper feed rollers, 11 is a driving side roller, and 12 is a driven side roller , 13 is a support lever, 14 is a fulcrum, 15 is a spring, and 16 is an electromagnet.

Claims (1)

[Scope of Claims] 1. A paper feed tractor 5 that causes the continuous paper 2 to travel in the forward or reverse direction in the transfer section 4, and a drive that feeds the continuous paper 2 printed in the fixing section 6 to the stacker 8 while holding it therein. The printing device is equipped with at least one pair of paper feed rollers 10 consisting of side rollers 11 and driven rollers 12, and when the paper feed tractor 5 runs the continuous paper 2 in the forward direction, the paper feed tractor 5 The drive side roller 11 of the paper feed roller 10, which has a circumferential speed faster than the feed speed of the paper feed roller 10, contacts the back surface of the continuous paper 2 in a slip state and rotates in the forward direction. When the continuous paper 2 is caused to run toward the stacker while applying tension, and when the paper feed tractor 5 causes the continuous paper 2 to run in the opposite direction, the driving roller 11 is kept rotating in the forward direction. The paper feed roller 10
A printing apparatus characterized in that a driven roller 12 is driven by a support lever 13 to move away from the continuous paper 2.