JPH0276768A - sheet feeding device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a sheet feeding device such as a paper feeding device that feeds paper in a recording device, and particularly to a sheet feeding device such as a paper feeding device that feeds paper in a recording device, and in particular, a sheet feeding device that presses a sheet against a sheet feeding roller by a plurality of driven rollers to feed the sheet. The present invention relates to a sheet feeding device that rotates a roller to feed a sheet, and is provided with a release mechanism for releasing a driven roller from pressure contact with the sheet feeding roller.

[Prior Art] As a conventional sheet feeding device of this type, the structure of a paper feeding device for a recording device is shown in FIGS. 3 to 5. This is a structure previously proposed by the present applicant in Japanese Patent Application No. 59-272094, etc., as a structure capable of constructing a highly reliable release mechanism with a small number of parts.

In FIGS. 3 to 5, reference numeral 1 designates a platen of a recording table which also serves as a paper feed roller for feeding recording paper. The platen 1 has an axis 1a relative to the left and right side plates 2a of the frame 2 of the recording device.
It is rotatably supported by. The platen 1 is rotated as shown by arrow C in FIG. 3 by the drive of a paper feed motor (not shown), and feeds the recording paper 11 shown in FIG. 4. At one end of the shaft 1a of the platen 1, there is a release lever 10 for manually releasing the feed rollers 4, 5 from being pressed against the platen 1, which will be described later. It is pivoted so that it can rotate in the direction.

Next, a paper pan 3 is provided below the platen 1 for guiding the recording paper 11 along the outer periphery of the platen 1. The paper pan 3 is integrally molded from a molding material such as plastic into an arcuate curved shape corresponding to the platen 1.

Next, reference numeral 4.5 is a feed roller which is a driven roller that presses the recording paper 11 against the platen 1 and rotates as the platen 1 rotates. A plurality of sets of feed rollers 4.5 are provided along the axial direction of the platen 1, with the two shown in the figure forming one set. A plurality of sets of feed rollers 4.5 are commonly supported by the paper pan 3.

In order to rotatably support the feed roller 4.5, a rib 3a curved into an arc is integrally formed on the back surface of the paper pan 3, as shown in Figure M5. A shaft 4 of a feed roller 4.5 is attached to both ends of the rib 3a.
The bearing for rotatably bearing a and 5a is the hole 3b,
3b is formed. Two ribs 3a are provided for one set of feed rollers 4.5 in order to pivotally support both ends of the shafts 4a, 5a of the feed rollers 4.5.
They are provided at intervals corresponding to the length of 5a.

Further, in the paper pan 3, between adjacent ribs 3a, there is an opening 3f for allowing the outer peripheral surface of the feed roller 4.5 to face the inside of the paper pan 3.

3g is formed.

The feed roller 4.5 has an opening 3f.

Each shaft 4a, with a part of the outer periphery facing the 3g part,
The bearings of the rib 3a at both ends of 5a are the holes 3b.

3b, it is rotatably supported by the rib 3a and supported by the paper pan 3.

Next, a release plate 7 is provided below the paper pan 3 to support the paper pan 3 and to perform a release described later. The release plate 7 has a length substantially corresponding to the platen 1 and a substantially V-shaped cross section, and is provided parallel to the platen 1, that is, parallel to the paper pan 3. As shown in FIG. 5, projections 7C for bearings are formed at both ends of the release plate 7, and these projections 7c can be inserted into respective holes 2b for bearings formed on the left and right side plates of the frame. Accordingly, the release plate 7 is provided so as to be rotatable in the direction of the arrow X in FIG. 3 and in the direction of the arrow y in FIG. 3 using the projection 7c as a fulcrum. That is, the release plate 7 is provided so as to be rotatable toward and away from the platen 1.

In order to attach the paper pan 3 to such a release plate 7, arms 3d are provided on both sides of the central portion of the rib 3a of the paper pan 3, as shown in FIG.

3d projects horizontally, and a protrusion 3e projects from the outer surface of the distal end of the arm 3d, which is bent downward at a right angle. Further, a groove 30 having a V-shaped cross section is formed below the center of the rib 3a. Further, a notch 7b is formed at the top of the bent portion on the free end side of the release plate 7 at a position corresponding to the tip of pA3d of the rib 3a.

Then, by bending the tips of the arms 3d, 3d of the rib 3a inward and press-fitting them into the notches 7b, 7b, the tips of the arms 3d, 3d return to their original shapes, and the protrusions 3e engages with the edge of the groove 7b, the paper pan 3 is coupled to the release plate 7 and supported between the platen 1 and the release plate 7. With the paper pan 3 attached on the release plate 7 in this way, press the release plate 7.
V-shaped groove 3 with rib 3a at the top of the bent part on the free end side of
0. and paper bread 3
is attached, the paper pan 3 approaches or moves away from the platen 1 relative to the release plate 7 depending on the distance from the upper end of the tip of the arm 3d of the rib 3a to the protrusion 3e. It is movable inside. That is, the paper pan 3 is attached to the release plate 7 with some play.

Further, in the above structure, a spring 9 is elastically loaded between both ends of the rear part of the release plate 7 and the spring hook 2c provided on the frame 2, and the tensile force of this spring 9 causes the release plate 7 to
As shown in FIG. 3, the free end side is biased in the X direction toward the platen 1.

With this structure, when the release lever 10 is operated to the position shown in FIG.
is rotated in the X direction by the biasing force of the spring 9 until the point P at the top of the bent portion on the distal end side of the release plate 7 comes into contact with the cam-shaped lower end of the release lever 10, and the vapor pan 3
2. Press the rib 3a in the direction toward the platen 1. This pressing force brings the feed roller 4.5 into pressure contact with the platen 1 as shown in the figure. This state is the normal state, and during recording, the recording paper (not shown) is moved to the feed roller 4 in this state.
, 5 are pressed onto the outer periphery of the platen 1. Then, recording is performed by driving a recording head (not shown) provided on the front left side of the platen 1 in FIG. , the line of the recording paper is advanced.

On the other hand, when releasing the feed roller 4.5 from pressure contact with the platen 1, the release lever 10 is rotated in the direction a to the position shown in FIG. Accordingly, the cam portion at the lower end of the release lever 10 presses the point P at the top of the release plate 7 downward, and the release plate 7 rotates in the direction of arrow X away from the platen 1. Along with this, the vapor pan 3 is displaced in a direction away from the platen 1.

Here, in the structure of the vapor pan 3 including the feed rollers 4 and 5, the rear side (the feed roller 4 side) of the groove 3c that engages with the top of the release plate 7 is constructed to be heavier than the front side (the feed roller 5 side). It is assumed that For this reason, as mentioned above, the vapor pan 3 is movably attached to the release plate 7 with some play, so that the vapor pan 3 has its fulcrum at the point P at the top of the release plate 7, as shown in FIG. This causes the feed roller 4 to fall backward.
is spaced apart from the platen 1. In this case, the feed roller 5 is pressed against the platen 1 only by the force that causes the paper pan 3 to fall, and the pressure contact is significantly weaker than in the state shown in FIG. In this way, the pressure of the feed roller 4.5 can be released. As shown in FIG. 4, the recording paper 11 can be inserted and set between the platen 1 and the feed roller 4 from the rear side.

According to the above structure, multiple sets of feed rollers 4
, 5 are supported by a common vapor pan 3, and the press contact and release of the feed rollers 4.5 are performed via the common release plate 7, so paper feeding with high reliability can be achieved at low cost with an extremely small number of parts. The device can be configured.

[Problems to be Solved by the Invention] In the above-mentioned paper feeding device for a recording device, the accuracy of paper feeding depends on the accuracy of the rotation amount of the platen and the accuracy of matching between the rotation amount of the platen and the paper feeding amount. determined by

Here, the amount of rotation of the platen and the amount of paper feed match if the frictional force between the platen and the recording paper is large. However, in this case, it is necessary that the frictional force be uniform over the entire length of the platen in the longitudinal direction. For example, if the frictional force is strong on the left side of the platen in the longitudinal direction and weak on the right side, the left side of the recording paper will be fed in line with the platen, but on the right side, slipping will occur between the platen and the recording paper, causing the paper to be fed. The amount decreases, and as a result, the recording paper is not fed parallel but skewed.

Here, the frictional force is generated in proportion to the pressing force of the feed roller against the platen. In other words, in order to feed the paper with high precision, it is necessary that a plurality of sets of feed rollers provided in the longitudinal direction of the platen are pressed against the platen with sufficient and uniform pressing force.

However, in the structure shown in FIGS. 3 to 5 described above, since the release plate 7 presses the vapor pan 3 and presses the feed roller 4.5, the release plate may be twisted when manufactured. However, when the height of the point P at the top of the release plate 7 with respect to the left and right protrusions 7c differs along the longitudinal direction of the release plate 7, the following problem occurs.

That is, in that case, in the state shown in Fig. 3, the foot roller 4.5 presses against the platen 1 with sufficient contact force in the part where the point P is high and close to the platen 1, whereas the point P is low and is away from the platen 1. The pressure contact force of the feed roller 4.5 becomes weak in some areas, and if the height difference at the point P is large, the feed roller 4.5 may separate from the platen 1.

As the pressure contact force of the feed roller 4.5 against the platen varies along the longitudinal direction of the platen 1, the frictional force between the recording paper and the platen varies along the longitudinal direction of the platen, resulting in the above-mentioned There is a problem in that the recording paper is skewed when the paper is fed.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in a sheet feeding device having the above-described structure and to improve sheet feeding accuracy.

[Means for Solving the Problems] In order to solve the above problems, according to the present invention, in a sheet feeding device in which a plurality of driven rollers that press a sheet into contact with a sheet feeding roller are supported by a sheet guiding member, the sheet guiding member Each of the driven roller support portions is directly pressed in a direction approaching the sheet feeding roller by an elastic member so that the driven roller is brought into pressure contact with the sheet feeding roller,
On the other hand, a release member operated via a manual operation member to release the pressure contact is coupled to the sheet guide member and is movable in directions approaching and away from the sheet feeding roller;
By operating the release member and displacing it in the separating direction, the release member directly presses the elastic member in the separating direction, displacing the sheet guide member in the separating direction, and releasing the pressure contact. A structure was adopted.

[Function] According to such a structure, by making the pressing force of the elastic member that presses each of the driven roller support portions of the sheet guide member in a direction approaching the sheet feeding roller sufficient and uniform, the driven roller The roller can be brought into pressure contact with the sheet feeding roller with sufficient and uniform pressing force, and sheet feeding accuracy can be improved.

[Example] DESCRIPTION OF THE PREFERRED EMBODIMENTS Details of embodiments of the present invention will be described below with reference to the drawings.

1 and 2 illustrate the structure of a paper feeding device for a recording apparatus according to an embodiment of the present invention. This device is an improved version of the structure shown in FIGS. 3 to 5 previously proposed by the applicant. 3 in Figures 1 and 2.
Portions common or corresponding to those in FIGS. 5 to 5 are given the same reference numerals, and explanations of the common portions will be omitted since they are redundant.

The structure of this embodiment shown in FIGS. 1 and 2 is different from the structure shown in FIGS. 3 to 5 in that a plate spring 6 moves the rib 3a of the paper pan 3 in the direction approaching the platen 1. By pressing the feed roller 4.5, the feed roller 4.5 is brought into pressure contact with the platen 1.

The leaf spring 6 is formed into an elongated 5-shaped bent shape, and one leaf spring 6 is provided for each rib 3a of the paper pan 3. The leaf spring 6 is cantilever-supported by fixing the base end with a screw 12 on a support part 2d cut and raised on the bottom plate of the frame 2, and the tip, which is bent into a semicircular arc shape, serves as a release plate. The paper pan 3 is engaged with the groove 3c of the rib 3a of the paper pan 3 through the hole 7d formed in the paper pan 3, and is exposed to the hanging position. Note that since this spring 6 is provided, a spring for biasing the release plate 7 in the direction toward the platen 1 is not provided.

The structure of other parts is paper pan 3 and release plate 7.
The structure is the same as that shown in FIGS. 3 to 5 described above, including the connection structure not shown.

When the feed roller 4.5 is brought into pressure contact with the platen 1 under such a structure, the release lever 10 is rotated in the direction shown in FIG. 1 to the position shown. In this state, as shown in the figure, the tip of the leaf spring 6 engages with the groove 3c of the rib 3a of the paper pan 3, and the leaf spring 6 presses the vapor pan 3 upward in the figure to approach the platen 1. This pressing force brings the feed roller 4.5 into pressure contact with the platen 1.

In this state, the release plate 7, which is connected to the rib 3a of the vapor pan 3 by the above-described connection structure, has been pulled up to the position shown in the figure.

On the other hand, when the feed roller 4.5 is released, the release lever 10 is rotated in the direction of arrow a in FIG. 2 to the position shown. A release lever that faces the top of the free end side of the release plate 7 as the release lever 10 rotates.
The height of the lower end surface 10a of the release plate 10 is reduced, and being pressed by the lower end surface 10a, the release plate 7 is rotated in the direction of the arrow y, that is, in the direction away from the platen 1. The lower end 7a of the bent portion of each part of the rotating release plate 7 presses the leaf spring 6 downward in the figure to separate it from the platen 1, and the tip of the leaf spring 6 is separated from the rib 3a of the paper pan 3. , the pressure of the leaf spring 6 against the vapor pan 3 is released. As the release plate 7 rotates in the y direction, the paper pan 3 connected to the release plate 7 is displaced downward away from the platen 1, and the paper pan 3 falls backward and feed roller 4
is from platen 1 to feed roller 4.
．． 5 is released.

According to the structure of this embodiment as described above, the feed roller 4
．． Since the feed roller 4.5 is brought into pressure contact with the platen 1 by pressing each of the ribs 3a of the vapor pan 3 which pivotally supports the feed roller 4.5 with the leaf spring 6, the spring force of each of the leaf springs 6 is sufficiently large and uniform. By doing so, each of the plurality of feed rollers 4.5 comes into contact with the platen 1 with sufficient and uniform pressing force along the axial direction of the platen 1, and the recording paper 11 can be fed with high precision. .

Note that in the above explanation, one plate spring 6 is separately provided to press each rib 3a of the paper pan 3 that pivotally supports the feed roller 4.5, but the shape of the plate spring 6 is changed to a comb shape. It may be configured such that the plurality of ribs 3a are pressed in common by one leaf spring 6 as a tooth shape.

By doing so, the number of parts can be further reduced.

It goes without saying that the structure described above can be applied not only to paper feeding devices for recording devices but also to other sheet feeding devices.

[Effects of the Invention] As is clear from the above description, according to the present invention, in a sheet feeding device in which a plurality of driven rollers that press a sheet against a sheet feeding roller are supported by a sheet guiding member,
Each of the driven roller support portions of the sheet guide member is directly pressed in a direction approaching the sheet feeding roller by an elastic member to bring the driven roller into pressure contact with the sheet feeding roller, while a manual operation member is operated to release the pressure contact. A release member operated through the sheet guiding member is provided movably in the direction of approaching and separating from the sheet feeding roller, and the release member is operated by displacing the release member in the direction of separation. adopts a structure in which the elastic member is directly pressed in the separating direction to displace the sheet guide member in the separating direction to release the pressure contact, so that the sheet feeding device equipped with the release mechanism can be reduced in parts. It has the advantage of being able to be constructed at low cost with just a few pieces, and also being able to press multiple driven rollers against the sheet feed roller with sufficient and uniform pressing force, preventing skewing of the sheet during sheet feeding, and improving sheet feeding accuracy. is obtained.

[Brief explanation of the drawing]

1 and 2 are side sectional views of a feed roller in a press contact state and a released state, respectively, to explain the structure and operation of a paper feed device of a recording apparatus according to an embodiment of the present invention, and FIGS. FIG. 5 is a side sectional view of the foot roller pressure contact state and the released state for explaining the structure and operation of the feeding device, and FIG. 5 is a perspective view of the vicinity of the ribs of the vapor pan 3 and the release plate 7 in FIGS. 3 and 4. 1...Platen 2...Frame 3...Paper pan 3a...Rib 4.5...Feed roller 6...Flat spring 7...Release plate 27 Moomfun - Adjust the troller to the correct position. /1 Nedai E (Suni 1st place I9j fat Japanese melon Figure 2 Fee F roller /f: No. 1 cane good ball, /1 bundle, 1 device t, 11th ward H and Oshiu No. 3 figure

Claims (1)

[Claims] 1) In a sheet feeding device in which a plurality of driven rollers that press the sheet against a sheet feeding roller are supported by a sheet guiding member, each of the driven roller supporting portions of the sheet guiding member is directly moved in a direction approaching the sheet feeding roller by an elastic member. The driven roller is brought into pressure contact with the sheet feed roller by pressing, and a release member operated via a manual operation member to release the pressure contact is connected to the sheet guide member to approach and separate from the sheet feed roller. By operating the release member and displacing it in the separating direction, the release member directly presses the elastic member in the separating direction and displacing the sheet guide member in the separating direction. A sheet feeding device characterized in that the pressure contact is released.