JPH0756200Y2 - Paper feeder for printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Industrial Application Field The present invention relates to an improvement of a paper feeding device in a printer.

(2) Disadvantages of Prior Art Conventionally, as a paper feeding method by a printer, there are a friction driving paper feeding by using cut paper or roll paper and a tractor driving paper feeding by using fanfold paper, depending on the type of paper. Further, in the tractor-driven paper feeding, a so-called push paper feeding method in which the paper is pushed in the tractor front platen arrangement direction depending on the tractor arrangement mode with respect to the printer, and the paper already wound around the platen is guided upward by driving the tractor. There is a so-called pull paper feeding method of pulling out. The present invention is applied to a paper feeding device that performs tractor-driven paper feeding by a friction-driven paper feeding method and a push-paper feeding method among these paper feeding methods, and its mechanism and operation are as follows. In the case of friction-driven paper feeding, pinch rollers are pressed against the platen by swinging the release lever, and the paper guided between them is driven by the rotation of the platen that is interlocked with the paper feed motor as the drive source. The sheet sent to the setting side and wound around the platen via the paper guide is pressure-supported at the upper part of the platen via the bail roller. On the other hand, in the case of tractor-driven paper feed, the pinch roller is pressed and released from the platen by swinging the release lever, and the tractor is driven by the paper feed motor in conjunction with the drive source to feed the paper and guide the paper. The paper that has been rolled up through the platen and sent out to the side of the print head is pressure-supported on the platen via bail rollers. In the case of the push paper feed system driven by the tractor, the fanfold paper sent from the tractor is wrapped around the platen, and the paper is pressure-bonded and supported at the top of the platen via the bail roller, and the line feed is performed, but normally the printing is performed. The paper feed amount by the platen is designed to be slightly larger than the paper feed amount by the tractor so that the paper does not get tangled due to entanglement with quality, and the paper is always cooperated by the platen and the bail roller. Is formed to pull. For this reason, if the pressure force of the bail roller to the platen is increased, the paper pulling force of the platen increases,
Since the paper engaged with the drive pin of the tractor may be disengaged or the engagement hole of the paper may be damaged, the crimping force can be properly fed without causing the above-mentioned trouble. It was necessary to set it weakly so that it could be done. On the other hand, during friction drive paper feeding, when the trailing edge of the paper comes off the pinch roller, the paper is fed by the frictional force between the platen and the bail roller. There was a problem that the accuracy deteriorated and problems such as uneven feed pitch and skew were generated.

(3) Purpose of the present invention The present invention relates to the above improvement, and has a simple mechanism.
It is an object of the present invention to provide a reliable paper feeding device that is compatible with both friction and tractor drive paper feeding and can change the pressure force of the bail roller against the platen.

(4) Outline of the Invention Then, specifically, when the release lever, which is switched according to the selection of both drive paper feeds, is selected and switched to the friction drive paper feed state, the pinch roller is pressed against the platen and at the same time the bail roller By increasing the crimping force to the platen, on the other hand, when selectively switching to tractor drive paper feeding, the pinch roller is released from the platen,
At the same time, in order to reduce the pressing force of the bail roller to the platen, the displacement amount of the release lever at the time of the selection operation is used, and the spring force for bail roller pressing to the platen interposed between the release lever and the bail lever changes. By arranging the spring as described above, the object is achieved.

(5) Embodiment of the Invention A paper feeding device in the printer of the invention will be described below based on an embodiment. FIG. 3 is a state diagram in the case of friction driven paper feeding in a printer used as an electronic computer output terminal, and FIG. 4 is a schematic side view showing a state diagram in the case of tractor driven paper feeding. FIGS. A and 4A show the state of each set position of the release lever that is selectively set corresponding to each sheet feed, and FIGS. 3B and 4B show the state of the platen by the set of the release lever. It is a figure which shows the press-contact state of a pinch roller, and a release state. A cylindrical platen 1 is rotatably supported between a side frame (L) 2 and a side frame (R) 3 and has a paper feed gear wheel train driven by a paper feed motor (not shown). It is arranged so as to interlock with each other. A pinch roller 4 is rotatably arranged on the roller holder 5. Reference numeral 6 denotes a release lever, which is arranged through a pin 7 planted on the outer surface of the side frame (R) 3 and is prevented from being detached outward by a stop ring 8. The release lever 6 has a tooth portion 6A in a part thereof, and is attached to a release gear 10 fitted to a release shaft 9 having a semicircular sectional view, which is rotatably supported by side frames (R) (L) 3 and 4. It is formed to work together. Roller holder 5
As described above, the pinch roller 4 is rotatably arranged as described above, and the paper guide 5B and the through hole 5A for inserting the release shaft 9 are formed, and the platen direction is provided through elastic means (not shown). In the state shown in FIG. 4B, the release shaft 9 is elastically supported by being locked to the outer peripheral portion of the release shaft 9 having a semicircular cross section. The release shaft 9 forms a cam mechanism in cooperation with the roller holder 5, and the release gear 10 pivots in conjunction with the swinging of the release lever 6 so that the platen 1 moves above the roller holder 5. The pinch roller 4 is formed so as to release the pressure. As shown in FIG. 3B corresponding to the set position of the release lever 6 in FIG. 3A, the pinch roller 4 is in a state of being pressed against the platen 1 by the elastic force of the roller holder 5 which is elastically supported. By driving the platen 1 to rotate, the platen 1 and the pinch roller 4 cooperate to cut and roll paper.
11 Friction drive paper feeding is performed during use. FIG. 4 shows a state in which the release lever 6 in the state shown in FIG. 3 is swung in the direction of the arrow to a set position where the tractor drive sheet can be fed, and the rotation of the release gear 10 and the release shaft 9 which are interlocked by the operation. The roller holder 5, which is elastically supported by the movement, resists the elastic force, and the holder 5 is moved through the shaft 9.
By pressing and moving the bottom of the through hole 5A downward, the pinch roller 4 which is in the pressure-bonded state with respect to the platen 1 as shown in FIG. 3B is in the pressure-released state as shown in FIG. 4B. In this state, the fanfold paper 12 is fed by tractor drive (not shown). Reference numeral 13 is a print head for printing on the guided sheet.
FIGS. 1 and 2 correspond to FIGS. 3 and 4 and show the form of a bail roller and a bail lever, which are the main components of the paper feeding device of the present invention, and a spring for generating a crimping force against the platen of the bail roller. FIG. 1 is a diagram corresponding to FIG. 3 showing the friction drive sheet feed set position of the release lever 6, and FIG. 4 is a diagram showing the tractor drive sheet feed set position of the release lever 6. The corresponding drawing is shown in FIG. 2, and the relationship between FIG. 1A, FIG. 2A and FIG. 1B, FIG. 2B is that the bail roller is crimped to the platen at both positions. It shows a released state. In the figure, the roller holder 5 supporting the pinch roller 4 and the print head 13 are omitted for the sake of easy understanding of the gist of the present invention. Reference numeral 14 denotes a bail lever (L), which is rotatably arranged on a pin 15 planted in the side frame (L) 2 and is prevented from coming off by a stop ring 16. ) 3 side bail lever (L) 14
A bail lever (R) (not shown) forming a pair with is similarly rotatably arranged. Reference numeral 17 is a bail roller, and 18 is a bail roller shaft. The shaft 18 is supported between both levers (L) and (R), and the bail roller 17 is rotatably and slidably arranged on the shaft 18. I will do it. 19 is a bail lever
A spring hook 19 is formed in a leftwardly-shifted portion between a pin 15 serving as a rotation fulcrum in 14 and a bail roller 17, and the spring hook 19 and a spring hook lever 20 fitted to the release shaft 9 are provided.
A spring 21 is provided between the and. Then, the spring force causes the bail roller 17 to be uncompressed from the platen 1 (first
In FIGS. B and 2B), the bail lever 14 is held in the opening direction with respect to the platen 1 by tilting the spring 21 to the left around the pin 15 that serves as the pivot of the bail lever 14. When the bail roller 17 is pressed against the platen 1 (FIGS. 1A and 2A), the spring is moved to the right around the pin 15 that serves as the pivot of the bail lever 14. When the platen 1 is tilted, the platen 1 is configured to receive a pressing force by the spring force. The bail roller 17 shown in FIGS. 1A and 2A.
In the state of being pressed against the platen 1, the spring-latch lever 20 fitted to the release shaft 9 is set in the friction drive paper feed set state (FIG. 1A) with reference to the spring-latch position of the spring hook 19 of the bail lever 14. Is arranged so that the spring is pulled more than the tractor drive paper feed set state (FIG. 2A). Specifically, the bail roller 17
Is formed so that the pressing force against the platen 1 is strong enough to hold the paper at a predetermined position via the spring 21, while in the case of tractor drive paper feed, the platen is compared with friction drive paper feed. Bale roller against 1
The pressing force of 17 is formed so as to pull the paper within a range in which the engagement hole with the tractor pin of the fanfold paper is not damaged, and acts weakly so that the paper can slip and rotate. Therefore, it is possible to automatically switch and select an appropriate pressing force of the bail roller 17 to the platen 1 corresponding to the set position position of the release lever 6. The position of the spring-engaging part on the release lever side corresponds to various release lever mechanisms, and by utilizing the changed position due to the setting operation accompanying each paper selection of the lever, a predetermined spring force corresponding to each paper drive is used. As long as it can be given to the bail roller, it is not limited to the present embodiment and is arbitrary. Further, in the present embodiment, the spring interposed between the bail lever and the release lever mechanism is an example in which the spring is arranged so as to act as a pressure holding force against the platen and as a holding force when the pressure is released. Corresponding to the so-called friction drive paper feed and tractor drive paper feed set states, when the bail roller is pressed against the platen, the platen is set against the amount of paper feed by the tractor to prevent the slack of the paper during the latter paper feed set. Even if the paper feed amount is increased a little, if the paper can be fed while slip-rotating without damaging the engagement holes of the fanfold paper, the spring acts in the direction in which the bail roller always presses against the platen. The release lever and the bail lever may be operated manually or automatically. Well, these opening and closing mechanism can be applied in any case not intended to change the gist of the present invention.

(6) Effects of the Invention As described above, according to the paper feeding mechanism of the present invention, the release lever mechanism for releasing the pressure contact of the pinch roller to the platen and the platen at the position above the platen at the time of friction-driven paper feeding and tractor-driven paper feeding. A simple structure in which a bail lever that has a bail roller that guides the paper in cooperation with each other is organically connected via a spring supports each paper feed, and the appropriate bail roller crimping force against the platen. It is possible to provide a reliable paper feed mechanism that can automatically set

[Brief description of drawings]

1 to 4 show an embodiment of the present invention, FIGS. 1 and 3 are views showing a friction drive paper feeding state, and FIGS. , A side view in which the roller holder portion and the print head portion are omitted, showing a state in which the bail roller is released from the platen, and a state in which the bail roller is in the pressure-bonded state. FIGS. 3A and 3B show a release lever and a pinch roller for the platen. A side view showing the relative relationship, FIG. 2,
FIG. 4 is a diagram showing a tractor-driven paper feeding state, and FIGS. 2A and 2B are a roller holder portion, a printing state in which the bail roller is in a state of being released from the platen, and a state in which the bail roller is in a state of being pressed. A side view with the head part omitted, FIG. 4A,
FIG. 6B is a side view showing the relative relationship between the release lever and the pinch roller with respect to the platen. 1: Platen 4: Pinch roller 6: Release lever 14: Bail lever 15: Pin (bail lever swing fulcrum) 19: Spring hook 20: Spring hook lever

Claims (1)

[Scope of utility model registration request] Claims: 1. A release lever that supports friction driven paper feed and a tractor driven paper feed of a push paper feed system and presses a pinch roller against the platen, and a paper presser that presses the paper sent to the upper part of the platen to the platen. In a printer having a bail roller and a sheet feed amount by the platen somewhat larger than a sheet feed amount by the tractor, a bail lever that rotatably supports the bail roller has one end of a spring that acts as a crimping force for the printer. While being locked,
The other end is locked at a position that fluctuates due to the paper feed selection operation of the release lever, and the spring has a tensile force of the spring that is released when the pinch roller is pressed against the platen. Paper feeding device characterized by being arranged so as to be weak