JPH09263348A - Rolled paper feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically change nip pressure at setting and at ordinarily using a rolled paper. SOLUTION: A paper feed tray 1 receiving a rolled paper is detachably held with a casing 5. The rolled paper 2 received in the paper feed tray 1 is fed to an image forming part by a drive roller 3a and a pinch roller 3b arranged opposite to the drive roller 3a. Nip pressure by the drive roller 3a and the pinch roller 3b is obtained by a tension spring 7. The nip pressure is varied by up and down movement of a cam follower provided on one end of a swing arm 4 and engaged with the casing 5. When the paper feed tray 1 is fitted and detached against the casing 5, the cam follower is moved up and down interlocking with the motion, and hence when the paper feed tray 1 is drawn out for setting the rolled paper, pressing force by the tension spring 7 is reduced so as to reduce the nip pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll paper feeding device, and more particularly, when the roll paper is set on a carrying roller, the nipping force (so-called nip force) of the roll paper is made smaller than that during normal carrying. The present invention relates to a roll paper feeding device suitable for weakening the directivity of a conveyance roller.

[0002]

2. Description of the Related Art In a copying machine, a plotter, etc., a long recording paper (roll paper) wound in a roll shape may be cut and used according to an image size or a predetermined size. In this case, when a roll paper is newly set in the paper feeding device, the roll paper is stored in the paper feed tray, and then the leading end of the roll paper is unwound from the roll state and sandwiched between the transport rollers. The conveyance speed of the roll paper by this conveyance roller must be accurate. Especially, when the roll paper is cut into a predetermined size and used, the cutting length is controlled by the rotation amount of the conveyance roller. When there is a variation in the roll paper, the variation appears as a variation in the cut length of the roll paper. Therefore, it is general that the nip force of the transport roller is set to be strong so that the rotation of the transport roller is surely transmitted to the roll paper without slippage.

However, when the nip force is strong, there are the following problems. That is, if the roll paper is sandwiched obliquely between the transport rollers when the front end of the roll paper is first set, the orientation of the roll paper will not be corrected and the roll paper will be transported as it is because the roll paper has no degree of freedom in the axial direction of the transport rollers. As described above, when the roll paper is conveyed obliquely, the roll paper may be torn, an image transfer failure may occur, or a jam may occur.

Therefore, conventionally, a sub-roller having a weak nip force, which is used for nipping when setting roll paper, is provided separately from the main conveyance roller, and after feeding a certain length by this sub-roller, the main conveyance roller is fed. It is configured so that the leading end of the roll paper reaches.

Further, a thermal transfer printer is known in which the nip force of the conveying roller is released when the sheet is set and the sheet is conveyed by the platen roller (Japanese Patent Publication No. 5-84746). .

[0006]

The conventional roll paper feeding device described above has the following problems. That is, the main sub 1
When a pair of transport rollers is provided, there is a problem that a larger space is required and the number of rollers is increased because there is a space between the main transport roller and the sub transport roller.

On the other hand, when the roll paper is set and the conveyance is performed by the platen roller, it is not necessary to provide a separate roller. However, this is only valid for thermal transfer printers that use platen rollers,
It is difficult to apply as it is to an electrophotographic copying machine or the like in which roll paper is set at a position away from the printing section.

As described above, conventionally, it is necessary to add a roller dedicated to setting roll paper, or the operator must carefully perform work to prevent the paper from being inserted at an angle, which requires space. However, there is a problem that the operation becomes complicated. For this reason, there has been a demand for a feeding device that does not complicate the work of the operator and can prevent diagonal setting without taking up a large space.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems, to provide a roll paper feeding device which facilitates the setting of roll paper and prevents oblique feeding.

[0010]

SUMMARY OF THE INVENTION To solve the above problems and to achieve the object, the present invention provides a paper feed tray for storing roll paper, and a housing for detachably holding the paper feed tray.
A drive roller for feeding the roll paper housed in the paper feed tray to the image forming unit, a pinch roller arranged to face the drive roller, and a spring for pressing the pinch roller against the drive roller. And a pressing force reducing unit that reduces the pressing force of the spring unit when the paper feed tray is detached from the housing, in association with the detaching operation of the paper feed tray with respect to the housing. There are features.

Further, according to the present invention, in order to support the pinch roller, a swing arm provided so as to be rotatable around a contact point of the pinch roller and the drive roller is provided, and the spring means is swingable. When the pinch roller is configured to be pressed to the drive roller side by acting on one end of the arm, and is pivotally supported on the other end of the swing arm, and the paper feed tray is mounted in the housing. While restricting the swing arm from rotating by being urged by the spring means by contacting the inner surface of the housing, the inner surface of the housing when the paper feed tray is detached from the housing. A second feature is that a cam follower is provided to deviate from the above and relax the restriction of the rotation of the swing arm.

According to the first and second features, it is possible to reduce the pressing force of the spring means that presses the pinch roller when the paper feed tray is detached from the housing. Especially,
According to the second feature, when the paper feed tray is attached to the housing, the pressing force causes the cam follower to engage with the housing and restrict the rotation of the swinging arm. The pressing force due to effectively acts on the pinch roller. On the other hand, when the paper feed tray is detached from the housing, the cam follower and the housing are disengaged from each other, so that the restriction is relaxed and the swing arm freely rotates to some extent. It does not act on the pinch roller effectively, and decreases.

According to the present invention, a small pinch roller and a large pinch roller are arranged so as to face the drive roller, and the small pinch roller is pressed against the drive roller.
The second spring means, which is stronger than the spring means, presses the large pinch roller against the drive roller, and the paper feed tray moves in association with the attachment / detachment operation of the paper feed tray with respect to the housing. A third feature is that a pressing force releasing means for releasing the pressing force by the second spring means is provided when the force is released.

Further, according to the present invention, in order to support the large pinch roller, a swing arm provided so as to be rotatable around a contact point of the large pinch roller and the driving roller is provided, and the second spring means is provided. Is configured to act on one end of the swing arm to press the large pinch roller toward the drive roller side, and is pivotally supported on the other end of the swing arm so that the paper feed tray is inside the housing. When attached to the casing, the swinging arm contacts the inner surface of the casing and restricts rotation of the swing arm by being biased by the second spring means, while the paper feed tray is detached from the casing. A fourth characteristic is that a cam follower is provided which is released from the inner surface of the housing to release the restriction of the rotation of the swinging arm.

According to the third and fourth characteristics, when the paper feed tray is detached from the housing, the pressing force by the second spring means that presses the large pinch roller in conjunction with the detachment is Since it is released, only the small pinch roller is pressed by the drive roller. In particular, according to the fourth feature, when the paper feed tray is mounted on the housing, the pressing force causes the cam follower to engage with the housing to limit the rotation of the swing arm. The pressing force of the spring means effectively acts on the pinch roller. On the other hand, when the paper feed tray is disengaged from the housing, the cam follower and the housing are disengaged from each other, so that the restriction on the rotation of the swing arm is released and the swing arm freely rotates. The pressing force of the second spring means does not act on the pinch roller.

Further, according to the present invention, two areas having different friction coefficients are formed on the surface of the drive roller in the axial direction of the drive roller, and the large pinch roller is opposed to one of the two areas, The small pinch roller is opposed to the other of the two regions, and the combination of the large pinch roller and the small pinch roller allows the combination of the large pinch roller and the region facing the large pinch roller to be the small pinch roller and the small pinch roller. The fifth point is that the friction coefficient is selected so that the mutual frictional resistance is greater than the combination of the areas facing the small pinch roller.
There is a feature.

According to the fifth feature, a higher frictional resistance can be obtained between the large pinch roller and the driving roller, and a smaller frictional resistance between the small pinch roller and the driving roller.

[0018]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the drawings. 1 and 2 are cross-sectional views of a main part of a roll paper feeding device according to an embodiment of the present invention. In particular, FIG. 1 shows a mode in which the roll paper is set in the paper feed tray, and FIG. 2 shows a mode in the normal conveyance after setting the roll paper.

First, in FIG. 1, the paper feed tray 1 is pulled out from the apparatus main body 5 in the left direction in the drawing to accommodate the roll paper 2. The roll paper 2 is wound around a core 2a, and the paper feed tray 1 has a support mechanism (not shown) for rotatably supporting the core 2a. Drive roller 3 for paper feed tray 1
a and the pinch roller 3 pressed by the drive roller 3a
A conveyance roller pair 3 composed of b is provided. The drive roller 3a of the transport roller pair 3 is provided in a state where the supporting position is fixed with respect to the paper feed tray 1, and is driven by a motor (not shown).

On the other hand, the pinch roller 3b is rotatably supported by the swing arm 4. A cam follower 6 is provided at one end of the swing arm 4. This cam follower 6
Is preferably rotatable with respect to the swing arm 4, but is not necessarily rotatable, the device body (housing) 5
It suffices to have a smooth surface that can be slid smoothly on the bottom surface 5a.

One end of a tension spring 7 is attached to the other end of the swing arm 4, and the other end of the tension spring 7 is fixed to a plate 8 forming a transport path for the roll paper 2. The fixing place is not limited to the plate 8 and may be a part of the paper feed tray 1 or a fixed structure provided in the paper feed tray 1. In short, it suffices that the tension spring 7 urges the swing arm 4 to rotate counterclockwise in the figure around the contact point between the pinch roller 3b and the drive roller 3a.

Further, a mechanism is provided for restricting the rotation of the swing arm 4 and receiving the reaction force of the tension spring 7 when the swing arm 4 is biased in the counterclockwise direction. . That is, the cam follower 6 is attached to the swing arm 4.
Between the pinch roller 3b and the pinch roller 3b, a stud 10 standing on the paper feed tray 1 is engaged with the long hole 9. The stud 10 moves relative to the elongated hole 9 as the swing arm 4 rotates.

When the swing arm 4 is biased by the tension spring 7 to rotate, one end of the elongated hole 9 (the end near the upper side in the figure).
The rotation of the swing arm 4 is restricted when the stud 10 comes into contact with. Therefore, after that, the pinch roller 3b
Will be pressed against the drive roller 3a by the tensile force of the tension spring 7. As a result, when the leading end of the roll paper 2 is inserted between the drive roller 3a and the pinch roller 3b, the roll paper 2 is pinched by the pinch roller 3 with respect to the drive roller 3a.
It is conveyed by the nipping force (nip pressure) obtained by the pressing force of b.

Guide plates 11a and 11b are provided in front of the conveying roller pair 3, that is, on the upstream side in the conveying direction.
Behind the pair of transport rollers 3, that is, on the downstream side in the transport direction, a transport path is constituted by the plates 12, 13 and 14 in addition to the plate 8. A cutter 15 for cutting the roll paper 2 into a desired size is provided in the middle of the transport path.

The guide plate 11a is provided with a paper set sensor 16 for detecting the roll paper 2.
The paper set sensor 16 can detect that the front end of the roll paper 2 is inserted between the guide plates 11a and 11b. As the paper set sensor 16, an optical sensor that determines the presence or absence of the roll paper 2 by reflection or transmission of light, a limit sensor that mechanically detects the roll paper 2 by an actuator, or the like can be used.

The setting operation of the roll paper 2 having the above structure will be described. First, after the roll paper 2 is supported by the support mechanism of the paper feed tray 1, the leading end of the roll paper 2 is unwound from the rolled state and inserted between the guide plates 11a and 11b.
When the leading end of the roll paper 2 is detected by the paper set sensor 16, the detection signal is input to a drive control device (not shown) of the drive roller 2a, and a motor (not shown) coupled to the drive roller 3a is driven to drive the drive roller. 3a rotates.
This motor is preferably a stepping motor that determines the amount of rotation by the number of steps supplied.

When the front end of the roll paper 2 is sandwiched by the pair of transport rollers 3, the roll paper 2 is fed to the transport path constituted by the plates 8 and 12, and is fed out from the plates 13 and 14 to the extent that the front end can be seen. Drive roller 3a
Is stopped. At this time, the roll paper 2 is the plate 13,
A sensor equivalent to the paper set sensor 16 is provided, for example, behind the plate 14 in order to recognize that the leading end of the sheet 14 has been sent out. Then, the drive roller 3a may be stopped based on the detection signal of this sensor.

After stopping the driving roller 3a, the cutter 1
5 is driven to cut the roll paper 2. Since the leading end of the separated roll paper 2 projects to the rear of the plate 14, setting is completed by pinching and removing this projection by hand. In this way, it is guaranteed that the leading edge of the roll paper 2 is at the position of the cutter 15 when the setting is completed.

Next, the operation during normal use after the completion of setting will be described with reference to FIG. In the figure, the same symbols as those in FIG. 1 indicate the same or equivalent parts. After the setting of the roll paper 2 is completed as described above, the paper feed tray 1 is pushed into the apparatus main body 5. In addition, between the paper feed tray 1 and the apparatus body 5, the paper feed tray 1 can be smoothly pushed into the apparatus body 5,
In addition, it is preferable to provide a guide member such as a rail so that the guide member can be positioned at a predetermined position.

When the paper feed tray 1 is pushed into the apparatus main body 5 along the guide member, the cam follower 6 provided on the swing arm 4 rides on the slope of the bottom surface 5a of the apparatus main body 5, that is, the inlet portion 5b. Then, the swing arm 4 rotates clockwise around this contact while maintaining the contact between the drive roller 3a and the pinch roller 3b. The contacts slightly move as the swing arm 4 rotates. The rotation of the swing arm 4 ends when the paper feed tray 1 is further pushed and the cam follower 6 reaches the horizontal portion of the bottom surface 5a. As the swinging arm 4 rotates clockwise in this way, the tension spring 7 is further pulled from the time of setting, so that the force by which the pinch roller 3b is pressed by the drive roller 3a, that is, the nip pressure is increased.

When the paper feed tray 1 is pushed into the apparatus main body 5 and set at a predetermined position, the roll paper 2 can be fed. That is, when a paper feed command is input from a control device (not shown), the motor of the drive roller 3a starts rotating,
It rotates by the rotation amount determined based on the size information input together with the paper feed command. As described above, since the feed amount of the roll paper 2 depends on the rotation amount of the motor of the drive roller 3a, the pressing force of the pinch roller 3b is sufficiently large in order to suppress the variation in the feed amount due to slip or the like. It is necessary to have been done. In this regard, in the present embodiment,
Since the cam follower 6 is pushed up by the bottom surface 5a of the apparatus main body 5 during normal use, the roll paper 2 can be transported by a nip pressure higher than the nip pressure of the transport roller pair 3 when the roll paper 2 is set. 2 can be suppressed from slipping between the drive roller 3a.

After the motor is driven by a predetermined number of steps in accordance with the paper feed command, the motor is stopped and the cutter 15 is driven while the conveyance of the roll paper 2 is stopped to drive the roll paper 2
Disconnect. The separated roll paper 2 is fed to an image forming unit (not shown), and then conveyed by a conveying roller of the image forming unit. Thus, in this embodiment, a weaker nip pressure can be applied when the roll paper 2 is set, and a higher nip pressure can be applied during normal use.

Next, a modified example of the pinch roller movable portion for changing the nip pressure will be described. 3 is a front view of a main part of the pinch roller movable part, FIG. 4 is a plan sectional view of the same, and the same reference numerals as those in FIG. 1 denote the same or equivalent portions. 3 and 4, the sheet feed tray 1 is provided with a bracket 17, and the bracket 17 is provided with elongated holes 18 and 19 and a U-shaped groove 20. On the other hand, pinch roller 3b
Is supported on the swing arm 4 by a shaft 22 via a bearing 21. The outer periphery of the bearing 21 is double-D cut to form a parallel surface, and the parallel surface is fitted in the U-shaped groove 20. That is, the pinch roller 3b is guided by the U-shaped groove 20 so as to be displaceable in the biasing direction with respect to the drive roller 3a.

The oscillating arm 4 is provided with studs 23 and 24. The stud 23 is guided by the elongated hole 18 and displaced as the oscillating arm 4 rotates. Also, the stud 24
Is guided by the elongated hole 19 and displaced as the swing arm 4 rotates. One end of the tension spring 7 is connected to the stud 24, and the other end of the tension spring 7 is connected to the overhanging portion 1 of the bracket 17.
7a. Further, a cam follower 6 is provided at one end of the swing arm 4.

With this structure, when the paper feed tray 1 is attached to or detached from the apparatus main body 5, the cam follower 6 follows the apparatus main body 5 in accordance with the attaching / detaching operation.
The swing arm 4 is rotated to change the nip pressure in the same manner as indicated by.

Next, a second embodiment of the present invention will be described. In the above example, the nip pressure by the pinch roller 3b is weakened when the roll paper 2 is set. On the other hand, in the second embodiment, when the roll paper 2 is set, the nip pressure by the pinch roller 3b is completely released, and the pinch roller 3b is replaced by a second pinch roller whose nip pressure is reduced in advance. The roll paper 2 at the time of setting is conveyed.

FIG. 5 is a front view of a main portion of the feeding device according to the second embodiment, and FIG. 6 is a side view of the same. 5 and 6, the guide plate 11b is provided with an overhanging portion 11c,
The second pinch roller 26 was supported by the leaf spring 25 sandwiched and fixed by the overhanging portion 11c. The second pinch roller 26 is pressed against the drive roller 3a by the leaf spring 25, and this pressing force is equivalent to the pressing force by the tension spring 7 when setting the roll paper 2 described with reference to FIG.

The pinch roller 3b is supported by the swing arm 4 as described with reference to FIG. 1, but the nip pressure is completely released when the paper feed tray 1 is pulled out from the apparatus main body 5. In addition, the long hole 9 of the swing arm 4 and the long holes 18 and 19 of the bracket 17 are lengthened to increase the rotation amount of the swing arm 4. By doing so, the nip pressure of the pinch roller 3b is completely released when the roll paper 2 is set, and the nip pressure of the roll paper 2 is given only by the second pinch roller 26 having a small nip pressure.

In the second embodiment, since the second pinch roller 26 is arranged, the pinch roller 3b has two right and left sides.
It is divided into two. As for FIG. 3, pinch roller 3b
There is only one, but in this case as well, it may be divided into two left and right.

Next, the drive roller 3a and the pinch roller 3b
Also, the material and the like of 26 will be described. As described above, the nip pressure at the time of setting the roll paper 2 may be low, and the roll paper 2 may be free to some extent in the lateral direction, that is, in the direction orthogonal to the transport direction. On the other hand, the nip pressure may be high during normal use after the setting is completed. Therefore, in the second embodiment, the drive roller 3a and the pinch rollers 3b and 26 are configured as follows.

FIG. 7 is a front view of essential parts showing the drive roller and the like. In the figure, the pinch roller 3b is made of chloroprene rubber, and abrasive grains are applied to the portion A of the drive roller 3a which is in contact with the pinch roller 3b to prevent slippage from occurring with the roll paper 2. I chose

On the other hand, the second pinch roller 26 is made of plastic resin such as polyacetal, and the portion B of the driving roller 3a which is in contact with the pinch roller 3b is made of chloroprene rubber. This makes slipping relatively easy between the second pinch roller and the roll paper 2.

[0043]

As is apparent from the above description, according to the first to fifth aspects of the invention, when the paper feed tray is detached from the housing, the pressing force of the pinch roller is interlocked with this operation. Can be automatically reduced. Therefore, when the roll paper is set with the paper feed tray removed from the housing, even if the roll paper is inserted at an angle between the pinch rollers, the roll paper in the axial direction of the pinch roller Due to the degree of freedom, the orientation of the roll paper is corrected as it is transported.

As a result, even if the roll paper is inserted at a slight angle, the roll paper will not be fed as it is and the damage or jam of the roll paper will not occur. Therefore, the roll paper can be easily set. It Moreover, during normal transportation, the roll paper can be reliably transported with a high nip pressure.

In many cases, the roll paper is replaced with a new one before it is completely consumed. At this time as well, the nip pressure is automatically reduced, so that the roll paper that has been used until then can be easily pulled out, and the replacement operation becomes easy. Further, it is not necessary to separately have different rollers for setting the roll paper and for normally carrying the roll paper, thus saving space.

[Brief description of drawings]

FIG. 1 is a front view showing a state when a roll paper feeding device according to an embodiment of the present invention is set.

FIG. 2 is a front view showing a state of normal use of the roll paper feeder according to the embodiment of the present invention.

FIG. 3 is a front view of a main portion of a movable portion of a pinch roller.

FIG. 4 is a sectional view of an essential part of a pinch roller movable part.

FIG. 5 is a front view of a main portion of a pinch roller movable portion according to a second embodiment of the present invention.

FIG. 6 is a side view of a main portion of a pinch roller movable portion according to a second embodiment of the present invention.

FIG. 7 is a side view of essential parts showing a modified example of the drive roller and the pinch roller according to the second embodiment of the present invention.

[Explanation of symbols]

1 ... Paper feeding tray, 2 ... Roll paper, 3 ... Conveying roller,
3a ... driving roller, 3b ... pinch roller, 4 ... swing arm, 5 ... apparatus main body (housing), 6 ... cam follower, 7 ... tensile spring, 15 ... cutter

Claims (5)

[Claims] 1. A paper feed tray for containing roll paper, a housing for detachably holding the paper feed tray, and a drive for feeding the roll paper contained in the paper feed tray to an image forming unit. A roller, a pinch roller arranged so as to face the drive roller, a spring means for pressing the pinch roller against the drive roller, and the paper feed tray in association with the attachment / detachment operation of the paper feed tray with respect to the housing. A roll paper feeding device, comprising: pressing force reducing means for reducing the pressing force of the spring means when the tray is detached. 2. A paper feed tray for storing roll paper, a housing for detachably holding the paper feed tray, and a drive for feeding the roll paper stored in the paper feed tray to an image forming unit. A roller, a pinch roller arranged so as to face the drive roller, a swing arm that is rotatable about a contact point of the pinch roller and the drive roller to support the pinch roller, Spring means that acts on one end of the swing arm to press the pinch roller toward the drive roller side, and is pivotally supported on the other end of the swing arm, and when the paper feed tray is mounted in the housing. While restricting the swing arm from rotating by being urged by the spring means by contacting with the inner surface of the housing, the swing arm moves from the inner surface of the housing when the paper feed tray is detached from the housing. Rotation of the swing arm And a cam follower for alleviating the above limitation. 3. A paper feed tray for containing roll paper, a housing for detachably holding the paper feed tray, and a drive for feeding the roll paper contained in the paper feed tray to an image forming unit. A roller, a small pinch roller arranged to face the drive roller, a large pinch roller arranged to face the drive roller, and a first spring for pressing the small pinch roller against the drive roller. Means, second spring means that is stronger than the first spring means that presses the large pinch roller against the drive roller, and the paper feed tray is linked with the detaching operation of the paper feed tray with respect to the housing. A roll paper feeding device, comprising: pressing force releasing means for releasing the pressing force by the second spring means when the roll paper is released. 4. A paper feed tray for storing roll paper, a housing for detachably holding the paper feed tray, and a drive for feeding the roll paper stored in the paper feed tray to an image forming unit. A roller, a small pinch roller arranged to face the drive roller, a large pinch roller arranged to face the drive roller, and a first spring for pressing the small pinch roller against the drive roller. Means, a swing arm for supporting the large pinch roller and rotatable about a contact point of the large pinch roller and the drive roller, and a spring means stronger than the first spring means. Second spring means that acts on one end of the swing arm to press the large pinch roller toward the drive roller side, and is pivotally supported on the other end of the swing arm, and the paper feed tray is a casing. Worn inside the body In this case, the swing arm is restrained from being rotated by being urged by the second spring means by coming into contact with the inner surface of the casing, while the swing tray is separated from the casing when the paper feed tray is separated from the casing. A roll paper feeding device, comprising: a cam follower that is released from the inner surface of the housing to release the restriction of the rotation of the swing arm. 5. The drive roller is formed with two regions having different friction coefficients on the surface of the drive roller in the axial direction, the large pinch roller is opposed to one of the two regions, and the two regions are opposed to each other. The small pinch roller and the small pinch roller are opposed to each other, and in the combination of the large pinch roller and the small pinch roller, in the combination of the large pinch roller and the area facing the large pinch roller, the small pinch roller and the small pinch roller are combined. 5. The roll paper feeding device according to claim 4, wherein the friction coefficient is selected so that the mutual frictional resistance is larger than the combination of the areas facing each other.