JPH0350106Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention temporarily waits the paper conveyed from the paper feed table by the rotation of the paper feed roller in a registration roller device consisting of a pair of rollers, and The present invention relates to a paper feeding device that rotates the registration roller device at a timing to convey the paper to a printing section.

[Prior Art] Conventionally, in a paper feeding device, a registration roller device is formed by a pair of a timing roller and a guide roller, and one roller of the pair of rollers is made of a rigid solid such as metal or plastic. ,
The other roller is made of a relatively hard elastic material such as rubber. This registration roller device temporarily waits the paper conveyed by the paper feed roller at the tangential position of the pair of rollers, then starts rotating when the drum is in a predetermined rotation phase, and transfers the paper between the drum and press roller. It is configured to be transported between

[Problems to be solved by the invention] Therefore, if the paper is transported by the rotation of the paper feed roller and the leading edge of the paper is not always stopped at the tangential position of the pair of rollers, the paper may be transported incorrectly or the timing of the transport may be incorrect. Various inconveniences occur, such as the vertical alignment of the printed image. For example, when the registration roller device is formed of metal rollers and rubber rollers, when the leading edge of the paper conveyed from the paper feed table by the paper feed roller first contacts the metal roller, the friction of the outer peripheral surface of the metal roller Since the force is extremely small, it slides on the outer peripheral surface and stops at a tangent position between the metal roller and the rubber roller. Therefore, the paper is then reliably conveyed between the drum and press roller by the drive of the registration roller device, and is also conveyed to the printing units at the set timing, so there is no vertical irregularity in the image position that differs for each print. Does not occur. However, when the leading edge of the paper first contacts the rubber roller, the outer circumferential surface of the rubber roller has a relatively high frictional resistance, so the leading edge of the paper does not slide all the way to the tangential position between the rubber roller and the metal roller. It will stop at that position. Therefore, even if the registration roller device is subsequently driven, the paper may not be conveyed, or
Even when the image is conveyed, there is a timing delay in conveying it between the drum and the press roller, so the position of the printed image is shifted compared to a normal, normal printed image. This is not much of a problem when printing in one color, but when printing in multiple colors, it is necessary to print on the same paper for the number of colors used, so if the printed image position shifts for each printing of different colors, the final A sharp image becomes a blurry image. This is the same even if the material of the rollers of the registration roller device is reversed. Additionally, the above-mentioned drawbacks vary somewhat depending on the shape of the guide plate that regulates the conveyance direction of the paper between the paper feed roller and the registration roller, but if the paper itself is curled or folded, the shape of the guide plate may change. Regardless, the above-mentioned drawbacks arise.

Therefore, in order to eliminate the above-mentioned drawbacks, both of the roller pairs of the registration roller device may be made of a rigid solid such as metal or plastic, but the following drawbacks occur.

If these metal roller pairs are not installed in the device in a perfectly circular and parallel state, only a portion of the paper will be conveyed in contact with the metal roller pair, and the paper will be conveyed in a direction perpendicular to the paper conveyance direction. This has the disadvantage that the degree of freedom of the paper is increased, and the paper may be skewed due to contact with the guide plate during conveyance.

Therefore, this problem can usually be solved by forming one of the rollers from an elastic member and pressing the other roller so that the paper is conveyed with both rollers in contact with each other.

In addition, in a printing device, one of the rollers of this registration roller device is used when the paper is being conveyed under pressure by the drum and press roller (during printing).
The rollers are configured to release the paper so as not to create resistance to the pressure conveyance, so that after printing one sheet, both rollers are in contact again and wait for conveyance of the next sheet. At this time, when both rollers are the metal rollers mentioned above, the pressing contact between the two rollers is usually formed by a spring, etc., so when the relief is released, the metal rollers collide with each other due to the spring force of the spring, causing an impact noise. emits. Naturally, the faster the printing speed is, the more the impact noise becomes. In order to prevent this impact noise, it is desirable that the registration roller be formed of a roller made of a rigid solid such as metal and a roller made of an elastic material such as rubber. It is necessary to simultaneously eliminate the disadvantages of rollers made of metal or the disadvantages of using only metal rollers.

The present invention was developed in view of the above points, and the leading edge of the paper is smoothed by smoothing the outer peripheral surface of the elastic member roller provided to the roller made of a rigid solid such as metal or plastic. It is an object of the present invention to provide a paper feeding device that can reliably stop the paper at a tangential position of a pair of rollers and thereby transport the paper in a timely manner.

[Means for Solving the Problems] Therefore, the paper feeding device according to the present invention transfers the paper P conveyed from the paper feeding table 1 by the rotation of the paper feeding roller 12 to the registration rollers consisting of a pair of rollers 23 and 24. It is a paper feeding device that temporarily waits in the device 22 and rotates the registration roller device 22 at a predetermined timing to convey the paper P to the printing section. It is characterized by comprising a first roller 23 and a second roller 24 made of an elastic member whose outer peripheral surface 24a is provided with a smooth surface layer 31 subjected to a smooth surface treatment.

[Function] Normally, the paper P conveyed by the paper feed roller 12
While being guided by the feeding plate 9 and the upper guide plate 20, the tip of the
The first roller 2 then stops at the tangential position of
3 is rotationally driven and the second roller 24 is driven, the paper P can be immediately conveyed to the drum 11 side.

Also, the paper P conveyed by the paper feed roller 12
The tips of the first roller 23 and the second roller 24
Even if the paper P contacts the second roller 24 side with a deviation from the tangential direction of The paper P is automatically positioned at the tangential position of the first roller 23 and the second roller 24, and can be immediately transported to the drum 11 side, and the paper P can be transported accurately and stably in a timely manner as usual. It can be transported by

[Example] The present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of the paper feeding device of the present application, FIG.
FIG. 3 is a diagram showing a state in which the paper conveyed by the registration roller device is stopped at a tangent position between both rollers.

In these figures, 1 indicates a paper feed tray, and this paper feed tray 1 has a fixed bottom plate 2 and a fixed bottom plate 2.
It has a movable bottom plate 4 whose rear edge is pivotally connected to the front edge thereof and which is rotatable about a substantially horizontal pivot 3, and the movable bottom plate 4 is supported by a spring 8 as shown in the figure. It is flexibly biased upward. A rear standing plate 5 is provided on the fixed bottom plate 2, and two side standing plates 6 and 7 are provided on the movable bottom plate 4. The fixed bottom plate 2 and the movable bottom plate 4 are stacked with sheets of predetermined size inside the rear standing plate 5 and side standing plates 6 and 7.

A feeding plate 9 is provided in front of the movable bottom plate 4 in the paper feeding direction, and extends from a position adjacent to the front edge of the paper feeding table to near the drum (plate cylinder) 11 along the paper feeding direction. . The feed plate 9 has a substantially perpendicular barrier wall 10 in a portion adjacent to the front edge of the paper feed tray in the paper feed direction, and the barrier wall defines a substantial front edge of the paper feed tray. are doing.

Further, a paper feed roller 12 is provided above the front edge of the paper feed tray 1 in the paper feeding direction. Paper feed roller 12
is supported on a rotating shaft 15, and is configured to be rotationally driven around its own axis in the counterclockwise direction in the figure. The paper feed roller 12 is made of a material with a relatively large coefficient of friction, such as rubber or a rubber-like product. It is adapted to come into pressure contact with the front edge of the paper P in the paper feeding direction. That is, the movable bottom plate 4 is urged upward in the figure by the spring force of the spring 8, and the paper P on the paper feed table 1 is pressed against the outer peripheral surface of the paper feed roller 12 by the spring force. do. Further, the portion of the feeding plate 9 facing the paper feeding roller 12 is cut out, and a paper handling pad 17 is provided in this cutout portion 16. The paper handling pad 17 is in contact with the outer peripheral surface of the paper feed roller 12 on its upper surface, is movable in the roller radial direction passing through the contact line, guided by a guide bar 17' and a fixing member 19, and is supported by a compression coil spring. 18 is pressed against the outer circumferential surface of the paper feed roller 12.
In addition, these paper feed rollers 12 and paper handling pads 17
The line of contact between the paper feed roller 12 and the paper P is somewhat offset from the line of contact between the paper feed roller 12 and the paper P in the paper feeding direction.

An upper guide plate 20 is provided above the feeding plate 9. The upper guide plate 20 is arranged between the upper guide plate 9 and the feed plate 9 in order to allow the paper to bend as shown in FIG. Guideway 2 having a substantially triangular longitudinal section
1 is defined.

The registration roller device 22 has a pair of first rollers 23 and second rollers 24, these rollers are synchronized with the rotation of the drum 11, and when the drum 11 is in a predetermined rotational phase, the first roller 23 starts rotating, and at the same time, the second roller 24 is driven to feed the paper P between the drum 11 and the presser roller 25.

The first roller 23 is made of a rigid solid such as metal or plastic, and the second roller 24 is made of an elastic material such as rubber. As shown, a smooth surface layer 3 made of extremely thin metal such as steel paper is provided. Also, as this smooth layer 31, the second
It is also possible to use a roller 24 in which metal is vapor-deposited on the outer circumferential surface 24a.

Note that the smooth layer 31 is attached to the first or second roller 23,
The second roller 24 may be formed of a material other than the above-mentioned smooth surface layer 31 as long as it is thin enough so that the elasticity of the second roller 24 is not impaired when in contact with the second roller 24 and has low frictional resistance.

Alternatively, the first roller may be formed of an elastic member, the smooth surface layer 31 may be provided on the surface, and the second roller 24 may be formed of a rigid solid.

Further, one of the first roller 23 and the second roller 24 is used when the paper is being conveyed under pressure by the drum 11 and the pressure roller 25 (during printing).
The material escapes so as not to create resistance to the pressure conveyance. The presser roller 25 has one end pivotally supported by a swinging lever 27 which is pivoted by a pivot 26, and the swinging lever 27 is supported by a compression coil spring 28 so that the presser roller 25 is connected to the drum. It is biased in the direction in which the outer circumferential surface of 11 is pressed. Further, 29 is a stripping claw, and 30 is a paper discharge table.

The operation of the above configuration will be explained below.

As shown in the enlarged view of FIG. 2, normally the leading edge of the paper P conveyed by the paper feed roller 12
It stops at a tangential position of the first roller 23 and second roller 24 while being guided by the upper guide plate 20, and then the first roller 23 is rotationally driven and the second roller 24 is driven. Then, the paper P can be immediately conveyed to the drum 11 side. At this time, since the second roller 24 is an elastic member, the first roller 24
Compared to 3, the entire surface can be in close contact and the impact noise is low.

Furthermore, as shown in FIG. 3, even if the leading edge of the paper P conveyed by the paper feed roller 12 deviates from the tangential direction of the first roller 23 and the second roller 24 and contacts the second roller 24 side, Since the smooth surface layer 31 is provided on the surface of the second roller 24, the leading edge of the paper P slides on this smooth surface layer 31 without friction and automatically moves to the first roller 23 and the second roller 24. The paper P can be positioned at the tangential position of the roller 24, and can be immediately transported to the drum 11 side, and the paper P can be transported accurately and stably with good timing as in normal times.

[Effects of the invention] As explained above, according to the paper feeding device according to the invention, the paper can be conveyed to the printing section in a timely manner and always in the same state, so that accurate and stable printing can be performed. Does not cause transportation defects or vertical irregularities.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram illustrating the paper feeding device of the present invention;
FIGS. 2 and 3 are enlarged views of a portion for explaining the operation of the registration roller device of the paper feeding device. 1...Paper feed stand, 12...Paper feed roller, 22...
Registration roller device, 23...first roller, 2
4... Second roller, 24a... (second roller) outer peripheral surface, 31... Smooth layer, P... Paper.

Claims (1)

[Scope of utility model registration request] The paper P conveyed from the paper feed tray 1 by the rotation of the paper feed roller 12 is temporarily held by a registration roller device 22 consisting of a pair of rollers 23 and 24.
At a predetermined timing, the registration roller device 2
2 is a paper feeding device that transports the paper P to a printing section by rotationally driving the registration roller device 22.
The first roller 23 made of a rigid solid and the outer peripheral surface 24
A paper feeding device comprising a second roller 24 made of an elastic member and having a smooth surface layer 31 that has been subjected to a smooth surface treatment.