JPS61254457A - Roll sheet stretching mechanism - Google Patents

Abstract

PURPOSE:To enable sheet stretching with different amounts of slacks between both ends of the sheet width by making a stretching member located at the lower part of the sheet possible to be swayed up and down at either end with supporting shaft arranged at the center of the sheet width as a fulcrum so that the side of the sheet having less slack is pushed downward and the side having more slack is pushed upward. CONSTITUTION:A roll sheet stretching member 20 is rotatable about a support pin 21 as a center so that always constant tension is given in the sheet surface direction as the side having too much tension is rotated about the support pin 21 downward and the side having slack upward, as in the case an ink sheet S, when attached to an ink sheet winder 14, is not correctly aligned in the sheet surface direction or in the case the ink sheet gets non-uniform slacks when the upper frame 2 is opened for jamming disposal or maintenance. Thus, adverse effect on printed letters due to wrinkles can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Industrial Field of Application The present invention is an image forming apparatus that uses a roll sheet or an ink sheet, such as a thermal printer, a facsimile machine, or a copying machine. This invention relates to a roll sheet tensioning mechanism for preventing this from occurring.

(B) Prior Art Conventionally, as a roll sheet tensioning mechanism for stretching a roll sheet or ink sheet, an idle roller is simply provided fixedly in the direction in which the roll sheet or ink sheet is stretched, or the present applicant was first filed in 1987-4875.
As described in No. 0, in contact with the ink sheet,
In addition, a guide mechanism whose central portion is curved convexly toward the ink sheet side is fixedly provided on the thermal head.

(C) Problems to be Solved by the Invention However, although the conventional techniques are effective in preventing sagging that occurs uniformly in the width direction of a roll sheet or ink sheet, If different amounts of sag occur at the edges, wrinkles in the rolled sheet or ink sheet cannot be prevented, and as a result, printing is adversely affected.

Therefore, it is an object of the present invention to provide a roll sheet tensioning mechanism that can effectively tension the roll sheet or ink sheet even when the roll sheet or ink sheet becomes sagging.

(D) Means for Solving the Problems The roll sheet tensioning mechanism according to the present invention is disposed between the roll sheet supply mechanism and the roll sheet winding mechanism, and includes a roll sheet tensioning member, and A spindle is provided near the longitudinal center of the roll sheet tensioning member, and the roll sheet tensioning member is configured to be movable up and down about the spindle.

Further, the roll sheet tensioning mechanism may be arranged between an ink sheet supply mechanism and an ink sheet winding mechanism, particularly in a thermal transfer printer.

Furthermore, the roll sheet tensioning member may also serve as a separation mechanism for separating the ink sheet and transfer paper after transfer.

(E) Operation If the roll sheet or ink sheet has different amounts of slack at one end and the other end in the width direction, the roll sheet tensioning mechanism will automatically roll the sheet with less slack around the fulcrum. It is pushed downward by the sheet or ink sheet, and the one with more slack rises to the upper side, so it is possible to always give tension to the roll sheet or ink sheet.

(F) Examples Next, specific examples of the present invention will be described with reference to the drawings.

FIG. 1 and FIG. 2 are a perspective view and a sectional view, respectively, when the roll sheet tensioning mechanism according to the present invention is applied to a thermal transfer printer.

In FIG. 2, the thermal transfer printer 1 can be divided into an upper frame 2 and a lower frame 3 around a support shaft 4, and the upper frame 2 includes a paper feed section 5 and a paper feed roller 6.
, upper and lower registration rollers 7°8, idle rollers 15. Platen roller9. Upper and Lower Jingi Roller 10.11. A paper discharge tray 12 is provided. The lower frame 3 has an ink sheet supply mechanism 13. A thermal head 161 separation mechanism 17° and an ink sheet winding mechanism 14 are provided.

Here, the ink sheet S is fed out from the ink sheet supply mechanism 13, passes through the idle roller 15, passes through the transfer section T formed by the platen roller 9 and the thermal head 16, and the separation mechanism 17, and then passes through the ink sheet winding mechanism 14.
It is wound up by. On the other hand, the transfer paper P supplied from the paper feed section 5 by the paper feed roller 6 passes through the upper and lower registration rollers 7.8 and is sent to the transfer section T, where it merges with the ink sheet S. In the transfer section T, the ink sheet) S selectively heated and melted by the thermal helad 16
The image is transferred onto a transfer paper P, and the transfer paper P and the ink sheet S are conveyed integrally to the separation mechanism 17.

Here, the ink sheet S is guided from the slightly rounded corner 17a of the separation mechanism 17 to the ink sheet winding mechanism 14, but the transfer paper P is discharged upward and downward by the stiffness of the paper and a guide plate (not shown). It is guided to rollers 10.11 and discharged onto a discharge tray 12. The reason why the separation mechanism 17 is shaped into a slightly rounded corner is to stabilize the separation position and reduce noise by increasing the horizontal force for separating the ink sheets at the corners. be.

In this embodiment, a roll sheet tensioning mechanism 1 according to the present invention will be described.
8 is provided between the separation mechanism 17 and the ink sheet winding mechanism 14. The roll sheet tensioning mechanism 18 includes a roll sheet tensioning member 20 extending in the width direction of the ink sheet S.
and a support member 22 that supports the roll sheet tensioning member 20.
It is supported by 2. The lower end of the support member 22 is fixedly supported by a screw 23 to a mounting plate 19 for fixing the separation mechanism 17 to the lower frame 3. As shown in FIG. 3, the roll sheet tensioning member 20 is rotatable around a support pin 21, and for example, when the ink sheet S is mounted on the ink sheet winding mechanism 14, the roll sheet tensioning member 20 can be rotated in the width direction. If the upper frame 2 is installed in the wrong shape or when the upper frame 2 is opened for jam removal or maintenance inspection)
Even when the ink sheet S sag unevenly, the side that is too tight in the width direction rotates downward around the support pin 21, and the side that is too slack rotates upward, so that the ink sheet S is always Uniform tension can be applied in the width direction. Therefore, in FIG. 3, the left side of the ink sheet S is slacker, and therefore rotates clockwise as shown by the two-dot chain line.

FIG. 4 shows another embodiment of the roll sheet tensioning mechanism,
In this embodiment, the roll sheet tensioning mechanism 24 also serves as a separation mechanism for separating the ink sheet S and the transfer paper P after transfer. The other parts are the same as those in FIG. 2 and are represented by the same reference numerals.

The rolled sheet tensioning mechanism 24 includes a rolled sheet tensioning member 27 and a support member 25.
It is supported by a support pin 26 that constitutes a support shaft, and is rotatable in the width direction about the support pin 26.

The support member 25 is fixedly supported by the lower frame 3.

In this embodiment, the ink sheet S and the transfer paper P that have passed through the transfer section T are separated at the slightly rounded corners 27a of the roll sheet tensioning member 27, as described above, and then transported to the ink sheet winding mechanism 14. Alternatively, it reaches the paper discharge tray 12. In that case, even if there is uneven slack in the width direction of the ink sheet S, the roll sheet tensioning mechanism 24 rotates about the support pin 26 as described above, so that uniform tension can be applied to the ink sheet S. I can do it.

Note that the embodiments of the present invention are not limited to those described above; for example, the roll sheet tensioning mechanism may be provided in the upper frame 2, and in that case, the roll sheet tensioning mechanism may be provided in a shape that presses the ink sheet S downward. Attach it to upper frame 2. That is, the roll sheet tensioning mechanism needs to be provided in a direction that always applies tension to the ink sheet S. Also,
It does not always have to be provided between the transfer section T and the ink sheet winding mechanism 14, but may be provided between the ink sheet supply mechanism 13 and the transfer section T. moreover,
In the embodiments, the roll sheet tensioning member is described as having a substantially rectangular shape, but it may also be cylindrical, and the shape is not particularly limited.

Further, when the present invention is applied to a facsimile machine or a copying machine that uses a roll sheet, in order to cut the roll sheet, a pair of transport rollers provided upstream of the roll sheet cutting mechanism in the transport direction of the roll sheet may be used. It becomes a roll sheet winding mechanism.

That is, in the present invention, the term "roll sheet winding mechanism" refers not only to an ink sheet winding mechanism that winds up a used ink sheet in a thermal transfer printer, but also to a cutting mechanism that cuts a roll sheet in a facsimile or copying machine. It also includes a pair of conveyance rollers that are provided on the upstream side in the conveyance direction of the roll sheet and that sandwich and convey the roll sheet.

CG) Effects of the Invention As described above, by providing the roll sheet tensioning mechanism according to the present invention, even if the roll sheet or ink sheet sag unevenly in the width direction, the roll sheet tensioning member can be stretched around the spindle. , since it rotates so as to apply tension to the slacker side, it is possible to apply tension uniformly in the width direction, and as a result, it is possible to prevent the adverse effect of wrinkles on printing.

In addition, if the roll sheet tensioning mechanism also serves as a separation mechanism for separating the ink sheet and transfer paper after transfer, the number of parts can be reduced, assembly is easy, and costs can be reduced. It can be done cheaply.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a roll sheet tensioning mechanism according to the present invention;
FIG. 2 is a cross-sectional view of a thermal transfer printer to which a roll sheet tensioning mechanism is applied, FIG. 3 is a diagram showing the operating status of the roll sheet tensioning mechanism, and FIG. 4 is a diagram showing other parts of the roll sheet tensioning mechanism according to the present invention. It is a figure showing an example of. l... Thermal transfer printer 5... Paper feeding section, 6... Paper feeding roller. 7.8... Registration roller 9... Platen roller 10.11... Paper discharge roller 12... Paper discharge tray 13... Ink sheet supply mechanism 14... Ink sheet winding mechanism 16...・Thermal head 17.24...Separation mechanism 18.24...Roll sheet tensioning mechanism 21.26...
・Support pin (spindle) S...Ink sheet (roll sheet) Patent claimant: Sanda Kogyo Co., Ltd.

Claims (4)

[Claims] (1) A roll sheet tensioning mechanism disposed between a roll sheet supply mechanism and a roll sheet winding mechanism for tensioning a roll sheet so that no slack occurs, the roll sheet tensioning mechanism comprising: A roll sheet tensioning mechanism comprising a roll sheet tensioning member, a support shaft provided near the longitudinal center of the roll sheet tensioning member, and configured to be movable up and down about the support shaft. (2) An ink sheet supply mechanism that feeds out an ink sheet, an ink sheet winding mechanism that winds up the ink sheet, and a thermal head and a platen roller provided between the ink sheet supply mechanism and the ink sheet winding mechanism. a transfer section configured by a paper feed roller and a registration roller for feeding the transfer paper from the paper feed section to the transfer section; and a separation mechanism for separating the transfer paper and the ink sheet after thermal transfer. In a thermal transfer printer equipped with a paper discharge roller for discharging separated transfer paper to a paper discharge tray, an ink sheet is stretched between the ink sheet supply mechanism and the ink sheet winding mechanism. The roll sheet tensioning mechanism has a roll sheet tensioning member, and a support shaft is provided near the longitudinal center of the roll sheet tensioning member, and the roll sheet tensioning mechanism is configured to move vertically around the support shaft. A roll sheet tensioning mechanism in a thermal transfer printer, characterized in that it is configured to (3) The roll in the thermal transfer printer according to claim 2, wherein the roll sheet tensioning member also serves as a separation mechanism for separating the ink sheet and the transfer paper after transfer. Seat tensioning mechanism. (4) The roll sheet tensioning mechanism in a thermal transfer printer according to claim 3, wherein the roll sheet tensioning member has a slightly rounded rectangular shape.