JPH07119137B2 - Paper feed mechanism - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeding mechanism such as a printer and a printing device.

[Prior Art] FIGS. 8 and 9 show a conventional sheet feeding mechanism.

In the figure, 16 is a first drive shaft and 26 is a second drive shaft.
Both drive shafts 16 and 26 are arranged in parallel, and these drive shafts 16 and 26 are
The print head 1 is reciprocated in the axial direction of 26 by a carrier (not shown).

The paper 3 is the feed roller 1 arranged on the first drive shaft 16.
2,12,12 and bail rollers 22,2 arranged on the second drive shaft 26
It is sent to the print head 1 side while being pressed and urged by 2, 22.
The pressure contact is given by an urging means composed of springs 31 and 31, and the feed urging is given from a rotation source (not shown) via gears 17 and 27.

In order to achieve reliable feeding, each feed roller 12 is formed of a material such as rubber having a large friction coefficient, while each bail roller 22 is formed of a material such as a synthetic resin having a relatively small friction coefficient and difficult to transfer ink. There is.

Therefore, by rotating both drive shafts 16 and 26,
The paper 3 can be fed by the cooperation of the corresponding feed roller 12 and bail roller 22. The nip width is controlled by the outer diameter of the feed roller 12, the biasing force of the spring 31, and the like.

[Problems to be Solved by the Invention] By the way, under the current diversification, there is a strong demand for printing on considerably thick paper such as postcards and envelopes with the same printer.

Therefore, as shown in FIG. 10, the second drive shaft 26 inclines against the urging force of the spring 31 to the extent that the bail roller 22 comes into partial contact due to the thickness of postcards and the rigidity thereof. Therefore, paper 3
However, there was a problem in that the skew and the inclination occurred, and high-precision feeding could not be performed.

As a countermeasure against this, as shown in FIG. 11, the center bail roller 22 is formed by an elastic member that is easily deformable, or the roller deformation shown in FIG. 12 is not changed, but the second drive shaft 26 is deformed. A scheme has been proposed.

However, in the roller deformation method, since the elastic member that is easily deformed generally has a large friction coefficient, the paper feeding accuracy becomes unstable in relation to other bail rollers and the printing surface side of the paper is soiled by the ink transfer. Remained. On the other hand, in the shaft deformation method, it is convenient for a thick postcard or the like, but if there is an imbalance of the springs 31 and 31, the shaft is easily deformed even if the paper 3 is thin. As a result, as shown in FIG. Since the bail roller in the center floats and the bail rollers on both sides touch each other, there is a drawback in that the main customer falls over, which is that skew and skew are not improved.

Further, as shown in FIG. 14, an independent urging system has been proposed in which each bail roller 22 is urged by an independent spring 32 in order to prevent one-sided contact.

However, in this case, not only the structure is complicated and the cost is increased, but also it becomes difficult to drive each bail roller 22 in terms of space, and each bail roller 22 must be rotatably attached to each shaft.

Therefore, when each bail roller 22 and each feed roller 12 are driven together, it is possible to generate a paper feeding force on both rollers 12, 22, but since the bail roller 22 is freely rotatable in the independent biasing method. Frictional resistance between each shaft and each bail roller, frictional resistance between each bail roller and a sheet are generated, and a frictional resistance force (load) is generated on the feed roller 12, which is extremely disadvantageous in terms of the sheet feeding force. In addition, skew and skew cannot be completely prevented due to back tension or the like.

Furthermore, if the biasing force of each spring 32 is increased to prevent skew or the like, a permanent compression strain is generated in the feed roller 12, it is difficult to control the nip width, and an imprint of the bail roller 22 is left on the multi-layered paper. There is also the problem of being lost.

The present invention has been made in view of the above circumstances, and an object of the present invention is to skew regardless of the thickness of a sheet,
An object of the present invention is to provide a paper feed mechanism that achieves high-precision feeding that prevents skewing and the like, has no concern about durability and ink transferability, and has a simple structure and low cost.

[Means for Solving the Problems] In the present invention, both the feed roller and the bail roller are rotationally driven from the viewpoint of securing the paper feed force, and the second drive shaft is integrally spring-biased for the sake of simplifying the structure. In addition, the bail roller is made of a material with a low coefficient of friction that does not transfer ink to the part in contact with the paper, and it is easily elastically deformed.
It is formed to enable high-precision feeding without uneven contact.

That is, according to the first aspect of the present invention, a plurality of feed rollers spaced apart from each other on the first drive shaft, a plurality of bail rollers disposed corresponding to each feed roller on the second drive shaft, and each bail roller are fed. A sheet feeding mechanism provided with biasing means for pressing the rollers and feeding each of the feed rollers and the bail roller to feed the sheet. At least one of the bail rollers other than the bail rollers arranged at both ends of the second drive shaft. One has a double structure including an outer skin portion having a small friction coefficient and an inner layer portion that transmits the rotational power of the second drive shaft to the outer skin portion and is elastically deformable in the direction of the pressure contact force of the biasing means. The second part
It is composed of a plurality of outer skin part elements divided in the axial direction of the drive shaft.

The invention according to claim 2 is characterized in that an outer diameter of the bail roller having the double structure is formed to be larger than outer diameters of other bail rollers.

Further, the invention according to claim 3 is characterized in that a collar portion which is in contact with the inner layer portion is provided on the end side of the outer skin element of the bail roller having the double structure.

[Operation] According to the first aspect of the present invention having the above-described configuration, the paper sandwiched between the feed rollers is brought into contact with the outer skin portion having a small friction coefficient, so that there is no ink transfer or uneven contact.
In the case of thick paper, even if the second drive shaft is inclined, the inner layer portion is elastically deformed in the direction of the pressure contact force of the biasing means, so skew and skew due to one-sided contact do not occur, and necessary and sufficient power can be transmitted. High precision feeding is possible. Moreover, since the inner layer portion is formed of a plurality of outer skin portions that are divided in the axial direction, the amount of critical deformation of the inner layer portion can be increased, and a sufficient pressure welding effect can be obtained.

In addition, in the invention described in claim 2, in addition to the action of the invention described in claim 1, since the outer diameter of the bail roller having a double structure is larger than that of the other bail rollers,
Further close contact and reliable pressure contact are guaranteed.

Further, in the invention described in claim 3, in addition to the action of the invention described in claim 1 or 2, the axial relative position of the outer skin portion and the inner layer portion is restricted by the collar portion, so that further. It is possible to press-contact securely, and it is easy to manufacture and assemble by adhesion.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

(First Embodiment) FIGS. 1 and 2 show a main part, and FIG. 3 is a front view showing the entire structure.

The paper feed mechanism is composed of a feed roller group, a bail roller group, and a gear mechanism that rotationally drives these.

As shown in FIG. 3, the feed roller group includes the first drive shaft 16
Of the three feed rollers 12, 12, which are integrally separated from each other
Each feed roller 12 is made of a rubber material having a large friction coefficient.

On the other hand, the bail roller group is composed of three bail rollers 22, 22, 22 integrally and separately arranged on the second drive shaft 26.

The bail rollers 22, 22 arranged on both end sides are formed integrally of a synthetic resin having a small friction coefficient and being difficult to be elastically deformed similarly to the conventional structure so that ink transfer is difficult.

Here, the bail roller, that is, the bail roller 22 at the center excluding both ends is provided with an outer skin portion 23 as shown in FIGS. 1 and 2.
And an inner layer portion 24.

Like the other bail rollers 22, 22, the outer cover 23 is made of a synthetic resin that has a small friction coefficient and is difficult to elastically deform from the viewpoint of difficulty in ink transfer. On the other hand, the inner layer portion 24 is configured so that even if the second drive shaft 26 is tilted when feeding the thick paper 3, one-sided contact does not occur, that is, the outer skin portion 23 can contact the paper 3 entirely. , Spring as biasing means
It is made of urethane foam or rubber that is easily deformed in the pressing direction of 31,31.

The inner layer portion 24 is formed into a perfect circular cross section in the normal state where the second drive shaft 26 is horizontal, the outermost portion is strongly bonded to the inner surface of the outer skin portion 23, and the innermost portion is strongly bonded to the outer surface of the second drive shaft 26. It is glued. Therefore, even if the inner layer portion 24 is elastically deformed, the rotational driving force from the second drive shaft 26 can be reliably ensured.
Can be transmitted to.

Here, even if the outer skin portion 23 has a large axial dimension of the bail roller 22 and the deformation amount of the inner layer portion 24 is limited, in order to obtain a sufficient pressure contact effect with the sheet 3, the axis line of the second drive shaft 26 is provided. Skin element divided into a plurality (two in this embodiment) in the direction
It is formed from 23-1 and 23-2.

The feed roller group and the bail roller group are the first
A gear 17 fixed to the drive shaft 16 and a second drive shaft meshing with the gear 17.
It is driven by a gear of a drive source (not shown) via a gear mechanism including a gear 27 fixed to 26.

The urging force that presses each bail roller 22 against each feed roller 12 is applied by an urging means including a pair of springs 31, 31 provided on both sides of the second drive shaft 26.

Thus, according to this embodiment, the central bail roller 22
Is formed from an elastically deformable inner layer portion 24 and an outer skin portion 23 composed of a plurality of outer skin portion elements 23-1 and 23-2 having a small friction coefficient, and all bail rollers 22 together with all feed rollers 12 are formed. Since the springs 31 and 31 that are driven to rotate are pressed against the corresponding feed rollers 12 by the biasing means, there is no gap between each feed roller 12 and each bail roller 22 in the normal state. High-precision feeding can be performed while reliably pressing the feed roller 12.

Even when the thick sheet 3 is fed, the inner layer portion 24 of the central bail roller 22 is elastically deformed as shown in FIG. In addition, the bail rollers 22, 22 on both sides do not largely hit one side or separate from the feed roller 12. Moreover, while the inner layer portion 24 is elastically deformed, the second layer
Since the rotational power from the drive shaft 26 can be effectively transmitted to the outer skin portion 23, and the outer skin portion 23 has a small friction coefficient,
Also in this case, it is possible to perform high-precision feeding with an appropriate pressure contact force.

Further, since the outer skin portion 23 is formed of a synthetic resin having a small friction coefficient, it is possible to perform clear printing or the like without ink transfer and dirt, as compared with a conventional roller deformation type rubber material. Along with that, stable paper feeding is possible.

Further, since the outer skin portion 23 is formed by the outer skin portion elements 23-1 and 23-2 divided in the axial direction of the second drive shaft 26, the length dimension of the central bail roller 22 can be made large, and
Even if the length dimension is increased, the limit of the deformation amount of the inner layer portion 24 is not suppressed to be small, and a sufficient pressure contact force can be obtained.

Further, since the second drive shaft 26 does not have to be elastically deformed, the structure is simple and the cost can be reduced, and high-precision feed that does not cause skew and skew due to one-sided contact can be guaranteed as compared with the conventional shaft deformation method.

Further, since the first drive shaft 16 is integrated and is properly pressed against the urging means composed of the pair of springs 31 and 31, as a whole, all the bail rollers 22 are provided together with the feed roller 12 as compared with the conventional independent urging method. It can be driven, effective transmission of rotational power and stable and reliable paper feeding. Further, since the pressure contact force of each bail roller 22 is made uniform and a certain bail roller 22 does not have an excessive pressure contact force, the compression of the feed roller 12 does not occur and the nip width can be easily controlled. It is possible to stably and highly accurately feed multi-layered paper without leaving an indentation on the sheet 3.

Second Embodiment The second embodiment is shown in FIG.

In the second embodiment, the bail roller 22 having a double structure has a larger diameter than the other bail rollers 22 as compared with the first embodiment.

That is, the thickness of the inner layer portion 24 is increased to make the outer diameter of the bail roller 22 having the double structure larger than the outer diameters of the other bail rollers by 2Δ to further improve the pressure contact effect.

Therefore, the second embodiment has the same effects as those of the first embodiment, and further, the closeness to the double-structure feed roller 12 (paper 3) can be further enhanced.

(Third Embodiment) A third embodiment is shown in FIG. 5 and includes outer skin elements 23-1, 23-.
2. That is, the outer skin portion 23 is provided with collar portions 23a, 23a which are in contact with the inner layer portion 24.

The collar portions 23a, 23a are provided mainly for preventing a relative positional change between the outer skin portion elements 23-1, 23-2 and the inner layer portion 24 in the axial direction.

Further, in this embodiment, the projections 5, 5 are provided on a stationary body such as a frame (not shown) so as to restrict the axial displacement of the flange portions 23a, 23a with respect to the second drive shaft 26.

Therefore, this embodiment has the same effects as those of the first and second embodiments, and further the outer skin portion 23 (23-1, 23-2).
And the inner layer portion 24 or the inner layer portion 24 and the second drive shaft 26 can be easily bonded, and, for example, a double-sided tape or the like will suffice, which is useful for cost reduction and has a double structure bail roller.
Position of 22 with respect to second drive shaft 26 and outer skin 23 and inner layer
The deformation effect of the inner layer portion 24 can be made more reliable and stable without being positioned with respect to 24.

In addition, in the above embodiment, the inner layer portion 24 is integrated,
As shown in FIG. 6, a split type (24-1, 24-2, 24-3) may be used.

Further, the number of the feed rollers 12 and the number of the bail rollers 22 are each three, but the numbers are not limited. The point is that if the bail rollers 22, 22 on both sides are made elastically non-deformable in order to regulate the position between the rollers 12, 22, all or some of the other bail rollers 22 in the middle of the bail rollers 22 and 22 are covered with the outer skin portion 23 and the inner layer portion. The object can be achieved even if it is formed from 24 and. For example,
As shown in FIG. 7, it is formed from 5 pieces each, and all of the middle (3
The bail rollers 22, 22, 22 may be elastically deformed to have a double structure. In this case, higher precision feeding can be performed.

[Effects of the Invention] As is clear from the above description, the invention according to claim 1 is characterized in that one or more bail rollers arranged in the middle are elastic with an outer skin portion composed of a plurality of outer skin portion elements having a small friction coefficient. Since it is formed of a deformable inner layer and all bail rollers are rotated by the same second drive shaft, conventional roller deformation method / shaft deformation method such as skew, skew, ink transfer, impression, etc. is independent. All the drawbacks of the biasing method can be eliminated, and stable and reliable high-precision feeding can be achieved even with thick paper such as postcards.

Further, in the invention according to the second aspect, since the outer diameter of the double structure bail roller is made larger than the outer diameters of the other bail rollers, the pressure contact action with the feed roller can be further promoted.

Further, in the invention according to claim 3, since the outer skin portion is provided with the flange portion that is in contact with the inner layer portion, the relative position between the outer skin portion / the inner layer portion and the inner layer portion / the second drive shaft can be reliably maintained. The pressure contact action can be further improved and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is an external perspective view showing a main part of a first embodiment of the present invention,
2 is a sectional view of the same, FIG. 3 is an overall configuration diagram for explaining the same operation, FIG. 4 is a front view showing an essential part of the second embodiment, and FIG. 5 is an essential part of the third embodiment. FIG. 6 is a front view in which a part is shown in section, FIG. 6 is a view showing a modification in which the inner layer portion is a split type, FIG. 7 is a view for explaining the operation of the modification in which five bail rollers are provided, and FIG. Figs. 14 to 14 show a conventional example, Figs. 8 to 10 show a case where both a feed roller and a bail roller are driven, Fig. 8 is a side view, and Fig. 9 is a front view.
Fig. 10 is a diagram for explaining the operation, Fig. 11 is a front view of a roller deformation method, Figs. 12 and 13 show a shaft deformation method, Fig. 12 is a front view and Fig. 13 is a case of feeding thin paper. FIG. 14 and FIG. 14 are front views showing the independent urging system for explaining the problem. 3 ... Paper, 5 ... Protrusion, 12 ... Feed roller, 16 ... First drive shaft, 22 ... Bail roller, 23 ... Outer skin part, 23-1, 23-2 ... Outer skin part element, 23a ... … Collar part, 24 …… Inner layer part, 26 …… Second drive shaft, 31 …… Spring (biasing means).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takeshi Hiyoshi, 570, Ohito, Ohito-cho, Ohito-cho, Takata-gun, Shizuoka Prefecture (56) References at the Ohito Plant of Tokyo Electric Co., Ltd. (56) Reference JP-A-58-207188 (JP, A) JP-A 1-286872 (JP, A) JP-A-62-21662 (JP, A) Actually open 59-131847 (JP, U) Actually open 53-3034 (JP, U)

Claims (3)

[Claims] 1. A plurality of feed rollers spaced apart from a first drive shaft, a plurality of bail rollers disposed corresponding to each feed roller on a second drive shaft, and a biasing means for pressing each bail roller against each feed roller. In the paper feeding mechanism for feeding paper by rotating each feed roller and bail roller, at least one of the bail rollers other than the bail rollers arranged at both ends of the second drive shaft is The outer skin portion has a double structure including a small outer skin portion and an inner layer portion that transmits the rotational power of the second drive shaft to the outer skin portion and is elastically deformable in the pressure contact force direction of the biasing means, and the outer skin portion is the second drive shaft. A paper feeding mechanism comprising a plurality of outer skin elements divided in the axial direction of. 2. The sheet feeding mechanism according to claim 1, wherein the outer diameter of the bail roller having the double structure is larger than the outer diameter of other bail rollers. 3. The sheet feeding mechanism according to claim 1, wherein a collar portion that is in contact with the inner layer portion is provided on the end side of the outer skin element of the bail roller having the double structure. .