JPH01269569A - Sheet feeder - Google Patents

Abstract

PURPOSE:To feed and discharge a sheet excellently regardless of the strength of the drape of the sheet of a record medium by operating more energizing means to a push member with the increase of reaction. CONSTITUTION:When a sheet 6 has weak drape and the reaction of the sheet 6 to the pushing of a spur wheel 24 is small, a stopper 25a is separated from a spring 29, the right end section of the spring 29 is engaged with a stopper 4a, and force is not worked to a taking-off guide 25. The taking off guide 25 is energized only by a spring 28 having weak resilient force, and the sheet 6 is pushed against a discharge roller 1. When the sheet 6 has strong drape and the reaction of the sheet 6 to the spur wheel 24 is large, the stopper 25a is engaged with the nose section of the right end section of the spring 29, the energizing force of the spring 29 works to the stopper 25a together with the spring 28 when the taking-off guide 25 intends to be turned in the counterclockwise direction from the guide 25 by the reaction of the sheet 6, the taking-off guide 25 is energized in the clockwise direction approaching to the discharge roller 1 by both energizing force of the springs 28 and 29, and the spur wheel 24 is energized in the same direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sheet feeding device for a recording device that feeds and discharges a sheet as a recording medium in the recording device.

[Prior Art] In recent years, as printers that use cut sheets as recording media have come into widespread use, attempts have been made to attach cut sheet feeders as an option to printers for automatically feeding cut sheets. In this case, if you attach the feeder externally to the printer body and provide separate power for it,
Since the number of parts increases and the cost also increases, efforts have been made to develop printers in which the feeder is incorporated into a sheet feeding device within the printer body.

In the case of a sheet feeding device that incorporates such a feeder, it is necessary to carry out everything from sheet feeding to ejection in a limited space, and in particular, for ejection, it is necessary to do so without having the platen roller hold the sheet for a long time after recording. It is necessary to eject the paper quickly and accurately so as not to adversely affect the recording quality.

FIGS. 6 and 7 illustrate a general configuration example of a sheet feeding device of a conventional printer incorporating this type of cut sheet feeder.

The configuration and operation will be described below from the upstream side of the sheet feeding flow of the recording medium.

In diagram N6, the first thing indicated by the symbol 10 is the pressure plate,
On this pressure plate 10, sheets (not shown), which are generally made of paper and serve as unused recording media, are stacked and set. The sheet on the pressure plate 10 is pressed against the feed roller 11 by the pressure plate 10 which is biased by a spring (not shown), and as the feed roller 11 is rotationally driven, the topmost sheet is separated through the separation claw 12. The seat pan separated and shown in Figure 7! a friction roller 3 that is guided by a friction roller 4 and feeds the sheet by frictional force; and a pinch roller 1 that presses the sheet 6 against the same roller 3.
Sent between 3. Arrow R of friction roller 3
By the rotation indicated by , the sheet 6 is sent to the front of the platen roller 2 which is rotatably provided above the friction roller 3 and serves as a recording stand and a sheet feeding roller.

Near the front of the platen roller 2, a carrier 16 is supported on a guide shaft 17.17 and is slidably provided in parallel with the platen roller 2. On the carrier 16 are four heads 5a of inkjet type in this case. A recording head 5 consisting of 5d to 5d is provided to face the platen roller 2.

During recording, the carrier motor 15 is driven so that the carrier 16 runs parallel to the platen roller 2 via the timing belt 30, for example in the F direction.

Each time the carrier 16 moves by a pitch corresponding to the pitch of the dot rows of the dot matrix, each of the recording heads 5 is driven, and a plurality of nozzles provided in each head are selectively driven according to the dot data of the recording data. Ink droplets are ejected, and the ink droplets are transferred onto the sheet 6 to perform dot recording. - When the recording of a row is completed, the platen roller 2 rotates in the direction of arrow R by a predetermined pitch corresponding to the pitch of one row, and the sheet 6 is sent one row upward in FIG. 7 in the sub-scanning direction. .

A plurality of ejection rollers 1 are provided above the platen roller 2 and supported by a shaft IA to eject the sheets 6 from the recording section. It is designed to be rotationally driven as shown by R. The discharge roller 1 is made of a material with a large coefficient of friction such as rubber, and has a fine linear groove IB on its outer periphery to engage and hold the rear *, i& of the sheet 6 when the sheet 6 is discharged. are circumferentially provided parallel to the axial direction of the discharge roller 1.

Further, near the front side of the discharge roller 1, a thin saw blade-like tooth (not shown) is provided around the outer periphery in order to press the sheet 6 against the discharge roller 1 and guide the discharge direction of the sheet 6. In this case, three sets of stage spurs 23,24 are provided for the three discharge rollers 1. The lower spur 23 is rotatably supported on the spur holder 4 via a shaft 26. The spur holder 4 is biased in the direction approaching the discharge roller 1 via the spring 8 and the spur lever 7. Spur shaft 22
7 through a bearing hole 4d, and is rotatably supported in the clockwise and counterclockwise directions in FIG. 7 to approach and move away from the discharge roller 1. The spur guide 4 has a groove 4e formed in the guide 4 and a pin 2 implanted in the spur shaft 22.
1, the spur 23 presses the sheet 6 onto the discharge roller 1. It looks like this.

Further, the upper spur 24 approaches and separates from the ejection roller 1 via a shaft 26 with respect to the spur holder 4, and is rotatable by a shaft 27 relative to a paper ejection guide 25 which is provided so as to be rotatable in the counterclockwise direction. It is pivoted. The paper ejection guide 25 is rotated toward the ejection roller 1 by a spring (torsion coil spring) 28 elastically loaded between a protruding stopper 25a protruding from its side surface and the spur holder 4 via a shaft 26. biased in the direction. As a result, the spur 24 presses the sheet 6 against the discharge roller 1.

With this structure, the sheet 6 is pressed onto the discharge roller 1 by the spurs 23 and 24, and the sheet 6 is fed as shown in the upper direction in FIG. 7 by the rotation of the discharge roller 1 in the R direction. When the trailing edge of the sheet 6 reaches the upper side of the discharge roller 1, the trailing edge of the sheet 6 falls into the groove IB of the discharge roller 1 through the guidance of the spur 24, engages with it, and is held.
The entire sheet 6 is conveyed onto the stacker 9 by the rotation of the discharge roller 1, and is stacked thereon. At this time, the spur 24 also functions to prevent the sheet 6 from falling to the left in FIG. 7 and to be carried onto the stacker 9.

[Problems to be Solved by the Invention] In the conventional printer sheet feeding device as described above, normally the urging force of the compression spring 20 for urging the lower spur 23 is equal to the urging force for urging the upper spur 24. The biasing force of the spring 28 is set to be stronger.

As mentioned earlier, the lower spur 23 is biased by the compression spring 2o.
presses the sheet 6 against the discharge roller 1, and the upper spur 24 presses the sheet 6 against the discharge roller 1 due to the bias of the spring 28, and when the sheet 6 is discharged, the rear end of the sheet 6 drops onto the stacker 9. At the same time, pressure is applied to wind the sheet 6 around the discharge roller 1.

However, when the sheet 6 is used to feed something stiff, such as a postcard or an envelope, the reaction force of the sheet 6 against the pressure of the spur 24 is large due to the stiffness of the sheet 6, and the spur 24 bounces against the sheet 6. In some cases, the corners of the sheet 6 wound around the discharge roller 1 become small. In this case, the feeding force when discharging the sheet 6 becomes small, and variations occur in the sheet feeding pitch after the trailing edge of the sheet 6 leaves the pinch roller 13. In other words, variations occur in the line feeding pitch, and the recording quality deteriorates. It will deteriorate.

On the other hand, if the spring force of the spring 28 is increased in order to increase the feeding force, the sheet 6
There have been problems in that the paper curls in the direction of wrapping around the discharge roller 1, and large impressions from the spurs 24 remain on the sheet 6.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate such drawbacks and to provide a sheet feeding device for a recording apparatus that can satisfactorily feed and discharge a sheet of recording medium regardless of its stiffness.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a discharge roller that discharges a sheet as a recording medium from a recording section of a recording device, and a rotation that presses the sheet against the roller. In a sheet feeding device of a recording device equipped with a pressing member capable of
A plurality of urging means for urging the pressing member to press the sheet are provided, and the number of urging means acting on the pressing member is determined according to the magnitude of the reaction force of the sheet against the pressing force of the pressing member. The pressing member is configured such that as the reaction force increases, more biasing means act on the pressing member.

[Function] According to such a configuration, when the seat is stiff and the reaction force of the seat against the pressure of the pressing member is large, the number of biasing means acting on the pressing member increases, and the pressing force of the pressing member is increased. becomes stronger, and sufficient feeding force can be obtained. Further, when the seat 6 is weak and the reaction force of the seat is small, the number of biasing means acting on the pressing member is reduced, the pressing force of the pressing member is reduced, and problems such as curling and impressions can be avoided. .

[Embodiment] Hereinafter, as an embodiment of the present invention, a sheet feeding device of the above-mentioned inkjet printer will be described with reference to FIGS. In these figures, the same reference numerals are given to the parts common or equivalent to those in FIGS. 6 and 7 of the conventional example, and the explanation thereof will be omitted.

1 Fork 11 FIGS. 1 and 2 are side sectional views for explaining the structure and operation of a sheet feeding device according to a first embodiment of the present invention.
The figure shows a case where the seat 6 has a weak back.
It shows that the waist is strong.

As shown in FIGS. 1 and 2, this embodiment differs from the prior art example in the structure for biasing the upper spur 24.

That is, the lower spur 23 is biased by a compression spring 20 elastically loaded between the spur holder 4 and the pin 21 as in the conventional example, whereas the upper spur 24 is biased by two springs (a torsion coil spring). ) 28 and 29.

The spring 28 is the same as the conventional spring 28, and has a weak spring force, and its middle part is wound around the shaft 26, and its left end part in the figure is locked to a stopper (not shown) of the spur holder 4. , the right end in the figure is locked to a stopper 25a in the form of a protrusion protruding from the side surface of the paper discharge guide 25. Then, the spring 28 causes the sheet discharge guide 2 to expand due to its elastic force.
5 in the clockwise direction in the figure as it approaches the discharge roller 1, and the spur 24 is urged in the same direction.

On the other hand, the second spring 29 is set to have a stronger spring force than the spring 28, and is loaded on the outside of the spring 28 (on the near side in the figure). The middle part of the spring 29 is wound around the shaft 26, and the left end part in the figure is locked to a stopper (not shown) of the spur holder 4. What locks the right end of the spring 29 differs depending on the rotational position of the paper ejection guide 25. When the paper ejection guide 25 is in the rotational position shown in FIG. The right end of the spring 29 is locked in the position shown in FIG. 2 when the paper discharge guide 25 is rotated counterclockwise from the position shown in FIG. The tip of the spring 28 is attached to the paper ejection guide 2 along with the tip of the right end of the spring 28.
It is adapted to be engaged and locked with the stopper 25a of No. 5. In this state where the right end portion is engaged with the stopper 25a, the spring 29 urges the paper ejection guide 25 clockwise in the figure to approach the ejection roller 1 due to its elastic force, and the spur 24 They are biased in the same direction.

With this structure, if the sheet 6 is weak and the reaction force of the sheet 6 against the pressing force of the spur 24 is small, the sheet discharge guide 25 is rotated to the position shown in FIG. 1 by the reaction force. In this state, the stopper 25a is separated from the spring 29, and the right end of the spring 29 is locked to the stopper 4a, and does not act on the paper ejection guide 25. The paper ejection guide 25 is moved only by the spring 28, which has a weak spring force. The sheet 6 is urged against the discharge roller 1.

In this case, even if the pressing force of the spur 24 is small, the sheet 6 is weak, so the sheet 6 is wound around the discharge roller 1 at a sufficiently large angle via the spur 24, and a sufficient feeding force can be obtained. There will be no variation in the line feeding pitch of the sheet 6 due to insufficient feeding force, and the spur 24
Since the pressing force is small, the sheet 6 will not curl as described above or leave large impressions of the spurs 24 on the sheet 6.

On the other hand, if the sheet 6 is stiff and the reaction force of the sheet 6 against the spur 24 is large, the reaction force causes the paper discharge guide 25 to
is rotated to the position shown in FIG. 2. In this case, the stopper 25a engages the tip of the right end of the spring 29,
When the paper ejection guide 25 attempts to rotate more roughly counterclockwise in the figure due to the reaction force of The pressing force of the 0 spur 24 that presses the sheet 6, which is urged clockwise toward the discharge roller 1 by the urging forces of both the 0 spurs 29 and the spur 24 is urged in the same direction, is much greater than that shown in FIG. It becomes a big thing. Therefore,
Even if the sheet 6 is stiff, the sheet 6 can be wound around the discharge roller 1 at a sufficient angle, and sufficient feeding force can be obtained. There is no variation in the line feed pitch of the sheet 6, and high-quality recording can be performed.

5 m Next, FIGS. 3 and 4 illustrate a sheet feeding device according to a second embodiment of the present invention. FIG. 3 shows a case where the seat 6 is stiff, and FIG. It shows that the waist is strong.

As shown in FIGS. 3 and 4, in this embodiment, as in the conventional example, the spurs 23 and 24 are biased by the compression springs 20 and 28.
It is now carried out by However, as a difference from the conventional example, a paper ejection guide 25 is located at the center of the upper end of the spur holder 4 in the figure in the direction of separation from the ejection roller 1 (
A stopper 4b in the form of a protrusion is provided in a protruding manner to limit the rotation limit when rotating in the counterclockwise direction in the figure.

Based on this structure, the seat 6 has a weak waist and the spur 24
When the reaction force of the sheet 6 due to the pressure is small, the paper discharge guide 25 is rotated to the position shown in FIG. 3 by the reaction force.

In this case, the back surface of the paper ejection guide 25 is away from the stopper 4b, and the urging force of only the spring 28 acts on the paper ejection guide 25, and the spur 24 presses the sheet 6 against the ejection roller 1 with the urging force. do. In this case, as in the case of the first embodiment shown in FIG. 1, a sufficient wrapping angle of the sheet 6 can be obtained, a sufficient feeding force can be obtained, and there is no problem of curling or impressions.

On the other hand, if the seat 6 has a strong waist and the reaction force of the seat 6 against the pressing force of the spur 24 is large, the reaction force causes the spur 24 to
4 is lifted, and the paper discharge guide 25 is rotated counterclockwise in the figure. When the paper discharge guide 25 rotates to the position shown in FIG. 4, the back surface of the paper discharge guide 25 comes into contact with the stopper 4b. If the paper ejection guide 25 attempts to rotate further counterclockwise, the spring 28 will move against the paper ejection guide 25.
With the biasing force of the compression spring 20 via the stopper 4b
The biasing force of will act. That is, the paper discharge guide 25 is biased clockwise by a strong biasing force that is the combination of the biasing force of the compression spring 20 together with the spring 28, and the spur 24 presses the sheet 6 against the discharge roller 1 due to this large biasing force. As a result, as in the case of FIG. 2 of the first embodiment, even if the sheet 6 is stiff, the sheet 6 can be wrapped around the discharge roller 1 at a sufficient wrapping angle, and sufficient feeding force can be obtained. Sheet feeding is performed accurately and well.

5m Next, FIG. 5 shows a sheet feeding device according to a third embodiment, which is a further improvement of the second embodiment of the invention described above.

As shown in FIG. 5, in this embodiment, as in the second embodiment described above, a stopper 4b is provided and a bearing hole 4d for bearing the spur holder 4 with respect to the shaft 22 is located in the upper right corner of the figure. It contacts the bottle 21 at the corner. Thereby, a stopper 4c is provided for restricting the rotation limit of the spur guide 4 in the counterclockwise direction in the figure.

Based on this structure, the back of the seat 6 is strong and the spur 24
If the reaction force of the sheet 6 against the pressing force of is large, 3
As in the case of the 42nd embodiment, the spur 24 is lifted by the reaction force, and the paper discharge guide 25 is rotated counterclockwise in the figure. When the paper discharge guide 25 comes into contact with the stopper 4b, a strong biasing force of the compression spring 20 as well as the spring 28 acts on the paper discharge guide 25. If the reaction force of the sheet 6 is stronger than this urging force, the spur guide 4 rotates counterclockwise in the figure together with the paper discharge guide 25.

However, when the spur guide 4 rotates slightly counterclockwise from the position shown in FIG. 5, the stopper 4c comes into contact with the pin 21, and the rotation of the spur guide 4 is completely restricted.

Then, due to the relationship between action and reaction, spur 2 is applied to sheet 6.
A pressing force equal to the reaction force of the sheet 6 acts as the pressing force of the sheet 5.

According to this embodiment, even if the sheet 6 is quite stiff and the reaction force against the pressing force of the spur 24 is quite large, the sheet 6 can be pressed with a corresponding pressing force, and the sheet can be fed accurately and well. be able to.

By the way, in each of the above embodiments, when the reaction force of the seat 6 is small, the urging force of one spring 28 acts on the spur 24, and when the reaction force of the seat 6 is large, the urging force of the two springs 28, 29 or 20, 28 acts on the spur 24. However, three or more springs are provided to bias the spur 24, and the seat 6
As the reaction force increases, a larger number of springs may sequentially act on the spur 24 to bias it.
The means for biasing the spur 24 is not limited to a spring, but other biasing means such as rubber may also be used.

In addition, the above-mentioned sheet feeding device is not limited to a structure in which the sheet is pressed against the ejection roller by a spur, but also in a sheet feeding device having a structure in which the sheet is pressed against the ejection roller by a roller! ! This biasing structure can be applied and similar effects can be expected.

[Effects of the Invention] As is clear from the above description, according to the present invention, there is provided a discharge roller that discharges a sheet as a recording medium from a recording section of a recording device, and a rotatable discharge roller that presses the sheet against the roller. In a sheet feeding device of a recording device including a pressing member, a plurality of urging means are provided for urging the suppressing member to press the sheet, and the pressing member is configured to press the sheet according to the magnitude of the reaction force of the sheet against the pressing force of the pressing member. The number of biasing means acting on the pressing member changes, and as the reaction force increases, more biasing means act on the pressing member, so that the reaction force of the sheet against the pressure of the pressing member is reduced. The pressing force of the pressing member can be changed appropriately according to the size of the sheet, and the sheet can be fed stably, accurately, and well regardless of the strength of the seat's waist. An excellent effect can be obtained in that problems such as these can be avoided.

[Brief explanation of the drawing]

1 and 's2 are side sectional views showing the structure and operation of a sheet feeding device section of a printer according to a first embodiment of the present invention, and FIGS. 3 and 4 are respectively a sheet feeding device according to a second embodiment of the present invention. 5th sectional side view showing the structure and operation of the
FIG. 6 is a side sectional view showing the structure and operation of the paper feeding device section according to the third embodiment, FIG. 6 is a perspective view showing the structure of the recording section and sheet feeding device section of a conventional printer, and FIG. A-A in Figure 6 shows the structure and operation of the sheet feeding device inside.
FIG. 1... Discharge roller 2... Platen roller 3... Friction roller 4... Spur holder 4a-4c... Stopper 5.
... Recording head 6 ... Sheet 9 ... Stacker
20... Compression spring 23.24... Spur 25.
・・Paper ejection guide 28.29・・Spring

Claims (1)

[Claims] 1) In a sheet feeding device of a recording device including a discharge roller that discharges a sheet as a recording medium from a recording section of the recording device and a rotatable pressing member that presses the sheet against the roller, the pressing member is attached. A plurality of urging means for pressing the sheet are provided, and the number of the urging means acting on the pressing member changes depending on the magnitude of the reaction force of the sheet against the pressing force of the pressing member, and the number of urging means acting on the pressing member is changed. A sheet feeding device characterized in that the larger the force, the more urging means act on the pressing member.