PAPER LOADING DEVICE OF PRINTER

Abstract: The invention provides a paper loading device for a printer wherein, when paper is to be loaded onto a platen, in response to operation of a button or a lever with paper set in position, the platen is driven to cause the paper to be loaded thereto, and upon such loading of the paper, a paper bail roller is automati­ cally moved away from the platen. After loading of the paper, the paper bail roller is returned to a position adjacent the platen.

Description: This invention relates to a paper loading device for a printer wherein a platen is rotated to feed paper wrapped therearound. Paper feeding means is already known wherein paper is held between a platen and pinch roller and is guided by a paper bail roller in a direction to be discharged from the platen. In a paper feeding means of this type, when paper is to be manually inserted between a platen and a printing station, a paper bail roller must be manually moved away from and to the platen troublesomely. Particularly when cut sheet paper is used, the paper bail roller must be manually moved from and to the platen for each paper sheet, and such operations are very troublesome. U.S Patent 4 275 969 discloses use of an over-centre spring operated bail arm, however this only has limited possibilities for variation of its mode of operation. The present invention has for its object the solution of the problem of providing a paper feeding device which can be automatically operated by electromagnetic means, and has simple possibilities of manual override. According to the present invention, there is provided a paper loading device for a printer, comprising: a platen connected to be rotated by a feed motor to feed paper; pinch rollers mounted for movement towards and away from said platen; a pair of left and right paper bail arms mounting a paper bail roller for rotation in opposing relation to said platen and mounted for pivotal motion to move said paper bail roller towards and away from said platen; an over-centre spring means for urging said paper bail arms towards and away from said platen on opposite sides of a neutral position of said paper bail arms; an operating member for controlling movement of said bail arms; and an electromagnetic actuating means displacing said operating member to provide movement of said paper bail arms; characterised in that said operating member comprises a stop to permit and constrain manual movement of the bail arms for release of pressure by the bail roller on the platen and is shaped to move the bail roller away from the platen on actuation of said electromagnetic means; and the device further comprises an operating lever which is shaped in relation to the shape of said operating member so that manual operation of said lever causes movement of the bail arms away from the platen and at the same time causes movement of the pinch rollers out of contact with said platen. The paper bail arms may be stopped by said stopper of said operating member at a position on the opposite side of said neutral position provided by said toggle spring when said paper bail arms are manually operated to move said paper bail roller away from said platen. In the conditions in which the bail arms are stopped by said stopper of said operating member at a position on the opposite side of said neutral position provided by said spring means when said paper bail arms are manually operated to move said paper bail roller away from said platen, if said operating member is displaced, said paper bail arms may be returned to said position just forwardly of said neutral position. A second pressing portion may be formed on said manipulating lever for pressing said operating member to move said paper bail roller away from said platen when said manipulating lever is pivoted to move said pinch roller away from said platen. A manipulating lever may be provided for positioning the pinch roller. The spring means may be a toggle spring. In one aspect of the invention, support means may be provided for resiliently supporting said paper bail arms at a position a little beyond a neutral position provided by said spring means. Following is a description by way of example only and with reference to the accompanying drawings of methods of carrying the invention into effect. In the drawings:- Figure 1 is a side elevational view of a first embodiment of the present invention showing a platen contacted by a pinch roller and a paper bail roller; Figure 2 is a similar but partial side elevational view showing the paper bail roller spaced from the platen by means of a solenoid; Figure 3 is a similar side elevational view showing the paper bail roller manually spaced from the platen; Figure 4 is a similar side elevational view showing the pinch roller and the paper bail roller both manually spaced away from the platen; Figure 5 is a block diagram; Figure 6 is a flowchart; Figures 7 and 8 are timing charts; An embodiment of the present invention will be described with reference to Figures 1 to 8. A platen 2 extends between and is supported for rotation on a pair of opposing side walls 1, and a paper pan 2a, a carrier shaft 3 and a guide 4 are located between the side walls 1. A carrier 5 is mounted for sliding movement on the carrier shaft 3 and the guide 4. A wheel motor 6 and a print wheel 7 connected thereto are mounted on the carrier 5, and a print hammer 8 connected to a solenoid (not shown) is also mounted for pivotal motion on the carrier 5. A ribbon cassette 9 is removably mounted on the carrier 5, and a guide plate 10 curved in an arc complementary to the platen 2 is also mounted on the carrier 5. Each of the side walls 1 has a recess 11 formed therein, and a pinch roller support plate 14 on which pinch rollers 12 and 13 are supported is supported at opposite ends thereof in the recesses 11 of the side walls 1 and is urged in a clockwise direction by a spring 15. A manipulating lever 17 is mounted for rotation on one of the side walls 1 by means of a pivot 18 and has an abutting face 16 which is opposed to a rear end of the pinch roller support plate 12. A pair of paper bail arms 20 on which a paper bail roller 19 is supported are mounted for pivotal motion on the left and right side walls 1 by means of pivots 21. Opposite hooks 25 of toggle springs 24 are hooked to pins 22 mounted on the paper bail arms 22 and pins 23 mounted on the corresponding side walls 1. An operating member 26 is mounted for pivotal motion around a pivot 28 on the one side wall 1 and is urged in a counterclockwise direction by a spring 27. The operating member 26 is connected to a plunger 30 of a solenoid 29 as an electromagnet secured to the side wall 1 and has formed thereon a pressing portion 32 for pressing against a projection 31 of one of the paper bail arms 20 and a stopper 34 for supporting a pin 33 mounted on the one paper bail arm 20. Meanwhile, the manipulating lever 17 has formed thereon a second pressing portion 36 for pressing against a bent lug 35 formed at a rear portion of the operating member 28. A cover 38 having an opening 37 formed therein is located above the platen 2. Further, as shown in Figure 5, a ROM 41 and a RAM 42 are connected to a CPU 40, and the wheel motor 6, the solenoid 29, a feed motor 43 coupled to the platen 2, and besides a carrier motor 44 for driving the carrier 5 are connected to the CPU 40 via an I/O interface 45. In this construction, in response to operation of a key on the cover 38, it is judged, as shown in the flowchart of Figure 6, if an automatic paper insertion code is set. If an answer is yes, then a current position of the carrier 5 is stored into a work area of the RAM 42, and an amount or distance over which the carrier 5 is to travel is set in accordance with a difference between the current position of the carrier 5 and the centre position of the carrier 5 and the centre position along the platen 2. Then, the carrier motor 44 is rotated forwardly or reversely to move the carrier 5 to a position opposing the centre of the platen 2. Then when paper 39 is put between the platen 2 and the paper pan 2a through the opening 37 of the cover 38, the feed motor 43 is turned on to rotate the platen 2 to feed the paper 39. Simultaneously, a soft timer starts its operation. Where the starting point of time is designated tO, the feed motor 43 is turned off and the solenoid 29 is turned on after a time t1 has passed. As a result, the plunger 30 is retracted from the position as shown in Figure 1 to a position as shown in Figure 2 so that the operating member 26 is pivoted in the clockwise direction about the pivot 28 against the urging of the spring 27 to push, at the pressing portion 32 thereof, the paper bail arm 20 away from the platen 2. However, the paper bail arm 20 is stopped at a position just forwardly of a neutral position by the stopper 34 of the operating member 26 abutting with the pin 33 on the paper bail arm 20. The toggle spring 24 has a tendency to develop or expand the hooks 25 thereof from each other, and in the position of Figure 2, the pin 22 is positioned below a straight line linking the pivot 21 and the pin 13 so that the toggle spring 24 urges the paper bail arm 20 to the platen 2, that is, in the clockwise direction. Referring back to Figure 6, when the time t of the soft timer reaches t2, the feed motor 43 is turned on so that the paper 39 inserted between the platen 2 and the paper pan 2a is fed under the guidance of the guide plate 10 of the carrier 5, by the platen 2 rotated by the motor 43 and cooperating with the pinch rollers 12 and 13. When the time t of the soft timer reaches t3, the feed motor 43 is turned off to end the automatic insertion or loading of the paper 39 and the solenoid 29 is turned off to allow the plunger 29 to move up so that the operating member 26 is returned in the counterclockwise direction by the force of the spring 27. As a result, the paper bail arm 20 which has been held stopped at the position just forwardly of the neutral position as shown in Figure 2 is now pivoted in the clockwise direction by the force of the toggle spring 24 to a position in which paper bail roller 19 holds down the paper 39 on the platen 2. After the paper 39 has been set in position, the initial position of the carrier 5 is read from the RAM 42 to allow subsequent ordinary printing operations in accordance with a program of the ROM 41. Accordingly, an operator can, at the beginning of printing operation, automatically load paper 39 only by operation of a key. Thus, when the paper 39 is inserted between the paper bail roller 19 and the platen 2 while the paper bail roller 19 is held spaced away from the platen 2 by energisation of the solenoid 29 and then the solenoid 29 is deenergised to allow the operating member 26 to be returned to its initial position, the paper bail arm 20 is pivoted to the platen 2 by the force of the toggle spring 24 to automatically hold the platen 2 with the paper bail roller 19 so that the paper 39 can be introduced certainly to the opening 37 of the cover 38 without being caught by a lower face of the cover 38. This is because, in Figure 2, the stopper 34 holds the paper bail arm 20 to the position just forwardly of the neutral position and hence the paper bail arm 20 is held urged in the clockwise direction by a force, though weak, of the toggle spring 24. Further, while, inserting the paper 39, the feed motor 43 is energised for a period of time from t0 to t1 of Figure 7 and at the time t1 the solenoid 29 is turned on to move the paper bail roller 19 away from the platen 2 whereafter the feed motor 43 is energised again for a period of time from t2 to t3 to insert the paper 39, the feed motor 43 and the solenoid 29 may otherwise be energised for a period of time from t1 to t3 to insert the paper 39. Meanwhile, the solenoid 29 is not energised before operation of the key for initiation of printing, and if in this condition the paper bail arm 20 is manually moved away from the platen 2, the paper bail arm 20 will be moved to a position a little beyond the neutral position and thereafter held thereto under an urging force of the toggle spring 24 acting in the counterclockwise direction. Thus, if the key is operated for initiation of printing, the solenoid will be energised for the period of time from t1 to t3 or from t0 to t3 as described hereinabove to pivot the operating member 26 in the clockwise direction so that the stopper 34 will press against the pin 33 to move the paper bail am 20 to the position a little displaced toward the platen 2 from the neutral position as seen in Figure 2. Accordingly, even when the paper bail arm 20 is manually moved far away from the platen 2, if the solenoid 29 is turned off at the time t3 after insertion of the paper 39, the paper bail roller 19 can be contacted with the platen 2 without fail, thereby preventing the paper 39 from being caught by the lower face of the cover 38. Further, referring to Figure 4, if the manipulating lever 17 is pushed leftwardly, the abutting face 16 thereof pushes up the pinch roller support plate 14 so that the pinch rollers 12 and 13 are moved away from the platen 2. In the meantime, the operating member 26 is pivoted in the clockwise direction by the pressing portion 36 of the manipulating lever 17 to push down the plunger 30 and to push, at the pressing portion 32 thereof, the paper bail arm 20 away from the platen 2. In this case, the paper bail arm 20 does not move beyond the neutral position thereof and is stopped and held to a position in which it is urged in the clockwise direction by the toggle spring 24. Accordingly, if the manipulating lever 17 is returned rightwardly to its initial position, the pinch roller support plate 17 is pivoted in the clockwise direction around the recess 11 by the urging of the spring 15 to move the pinch rollers 12 and 13 away from the platen 2 while simultaneously the operating member 26 is returned to its initial position by the urging force of the spring 27 and the paper bail arm 20 is returned to the position adjacent the platen 2 by the force of the toggle spring 24. since the paper bail roller 19 can be moved from and to the platen 2 in response to operations to move the pinch rollers 12 and 13 from and to the platen 2, a paper loading or inserting operation is very simple. This is very convenient when the pinch rollers 12 and 13 and the paper bail roller 19 are moved away from the platen 2 to make the paper 39 free.

Claims: A paper loading device for a printer, comprising: a platen (2) connected to be rotated by a feed motor to feed paper; pinch rollers (12,13) mounted for movement towards and away from said platen; a pair of left and right paper bail arms (20) mounting a paper bail roller (19) for rotation in opposing relation to said platen and mounted for pivotal motion to move said paper bail roller towards and away from said platen; an over-centre spring means (24) for urging said paper bail arms towards and away from said platen on opposite sides of a neutral position of said paper bail arms; an operating member (26) for controlling movement of said bail arms; and an electromagnetic actuating means (29) displacing said operating member to provide movement of said paper bail arms; characterised in that said operating member (26) comprises a stop (34) to permit and constrain manual movement of the bail arms for release of pressure by the bail roller (19) on the platen (2) and is shaped to move the bail roller away from the platen on actuation of said electromagnetic means; and the device further comprises an operating lever (17) which is shaped in relation to the shape of said operating member so that manual operation of said lever causes movement of the bail arms away from the platen and at the same time causes movement of the pinch rollers out of contact with said platen. A paper loading device for a printer according to claim 1, wherein said paper bail arms are stopped by said stopper of said operating member at a position on the opposite side of said neutral position provided by said toggle spring when said paper bail arms are manually operated to move said paper bail roller away from said platen. A paper loading device for a printer according to claim 1 or claim 2 wherein in the condition in which said paper bail arms are stopped by said stopper of said operating member at a position on the opposite side of said neutral position provided by said spring means when said paper bail arms are manually operated to move said paper bail roller away from said platen, if said operating member is displaced, said paper bail arms are returned to said position just forwardly of said neutral position. A paper loading device for a printer as claimed in any preceding claim including a second pressing portion formed on said manipulating lever for pressing said operating member to move said paper bail roller away from said platen when said manipulating lever is pivoted to move said pinch roller away from said platen. A device as claimed in any preceding claim including a manipulating lever for positioning said pinch roller. A device as claimed in any preceding claim wherein the spring means is a toggle spring. A device as claimed in any preceding claim including support means for resiliently supporting said paper bail arms at a position a little beyond a neutral position provided by said spring means.

Inventors: KAWAGUCHI, KATSUHIKO
Applicants: TOKYO ELECTRIC CO. LTD.
Application year: 1985
Main classification: B41J13
IPC codes: B41J13