JP3087589U - Printer and paper feed mechanism - Google Patents

Abstract

(57) [Problem] To provide a paper feed mechanism that can reduce the processing time by allowing the feed roller to rotate in reverse without waiting for the completion of the discharge of the previous paper, and can be manufactured at a low cost with a simple structure. . The number of gears interposed between a feed roller and a paper discharge roller is switched between when the feed roller rotates forward and when it rotates reversely. At the time of reverse rotation, the friction arm 5 rotates counterclockwise following the rotation of the feed roller, and the gear 12 engages with the gear 14. Further, when the gear 11 rotates in the y1 direction (reverse rotation direction), the rotation of the feed roller is performed by the six gears 11, 12, 14, 15, 16, and 17.
Is transmitted to the paper discharge roller via As a result, the gear 11
When the gear 17 rotates in the y1 direction, the gear 17 rotates in the y7 direction, and the paper discharge roller rotates forward even if the feed roller rotates in the reverse direction. Therefore, it is possible to feed the next sheet without waiting for the discharge of the previous sheet.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a paper feed mechanism in an ink jet printer or the like.

[0002]

[Prior art]

 FIG. 7 is a diagram schematically showing a paper feed mechanism 50 in a conventional ink jet printer. In the figure, 51 is a feed roller for feeding paper, 52 is a discharge roller for discharging paper, 53 is a belt stretched between the feed roller 51 and the discharge roller 52, and 54 is a feed roller A pinch roller that opposes and presses the paper, 55 is an arm that supports the pinch roller 54, 56 is a star wheel that conveys the paper opposing the discharge roller 52, and 57 is provided between the feed roller 51 and the discharge roller 52. This is the intermediate roller that was used.

The feed roller 51 and the paper discharge roller 52 are driven by a common motor (not shown), and when the feed roller 51 rotates, this rotation is transmitted to the paper discharge roller 52 via a belt 53, and the paper is discharged. The roller 52 also rotates. In FIG. 7, the feed roller 51 is normally rotating in the A direction, and accordingly, the paper discharge roller 52 is also normally rotating in the A direction. The paper (not shown) is fed by the normal rotation of the feed roller 51, and the paper on which printing is performed by a printing mechanism (not shown) is discharged between the discharge roller 52 and the star wheel 56.

[0004]

[Problems to be solved by the invention]

 By the way, when the paper is fed by the feed roller 51, if the paper is fed with the leading edge of the paper uneven, printing is performed diagonally on the paper. 8 is rotated in the direction of B once as shown in FIG. 8, the leading edge of the sheet waiting just before the feed roller 51 is aligned, and then the feed roller 51 is rotated forward in the direction of A as shown in FIG. Paper is fed one sheet at a time.

However, in the conventional paper feed mechanism 50, since the rotation direction of the feed roller 51 and the rotation direction of the paper discharge roller 52 are always the same, as shown in FIG. When the paper is reversed, the paper discharge roller 52 also rotates in the direction B. Therefore, when printing is continuously performed on a plurality of sheets, if the feed roller 51 is rotated in the reverse direction in a state where the trailing end of the previously fed sheet has not yet been fed from the discharge roller 52, the sheet is discharged. The sheet is pulled back by the roller 52, and a paper jam (jam) occurs. For this reason, conventionally, it is necessary to reverse the feed roller 51 after waiting for the previous paper to be completely discharged. This waiting time causes a time when printing is performed on a plurality of papers. Takes a long time.

On the other hand, by using a combination of a gear and a one-way clutch without using the belt 53 as in the above-described paper feed mechanism 30, a paper feed mechanism in which the paper supply / discharge roller always rotates in one direction. Is described in JP-A-8-259030. JP-A-7-117888 also discloses a paper feed mechanism in which a gear and a one-way clutch are combined so that paper feeding and paper discharging can be performed by one driving unit. However, one-way clutches have difficulty in ensuring the accuracy of parts, and are not always satisfactory in terms of operation stability. In addition, there is a limit in reducing manufacturing costs due to high costs.

The present invention solves the above-mentioned problem, and an object of the present invention is to shorten the processing time by allowing the feed roller to reversely rotate without waiting for the completion of the discharge of the preceding paper. Another object of the present invention is to provide a paper feed mechanism that can be manufactured at a low cost with a simple structure.

[0008]

[Means for Solving the Problems]

 The paper feed mechanism according to the present invention includes a feed roller for feeding paper, and a discharge roller for discharging the paper fed by the feed roller. A paper feed mechanism that feeds the paper by rotating the feed roller forward after aligning the paper.A movable mechanism that transmits the rotation of the feed roller to the paper discharge roller between the feed roller and the paper discharge roller. A gear block and a fixed gear are provided. When the feed roller rotates, the movable gear block rotates following the rotation direction, and the gear of the movable gear block engages with the fixed gear. The number of gears interposed between the feed roller and the discharge roller is switched between an even number and an odd number in accordance with the rotation direction of the feed roller, so that the discharge roller is independent of the rotation direction of the feed roller. Is always rotating forward.

With this configuration, the number of gears interposed between the feed roller and the discharge roller is automatically switched to an even number or an odd number in accordance with the rotation direction of the feed roller, and the feed roller rotates forward. In this case, as in the conventional case, the paper discharge roller rotates normally, and also when the feed roller rotates reversely, the paper discharge roller rotates forward by switching the number of gears. In this way, the paper discharge roller always rotates forward regardless of whether the feed roller is rotating forward or backward, so even if the feed roller is rotated in the reverse direction with the previous paper not being discharged from the paper discharge roller, the paper is discharged. Since the rollers maintain normal rotation, there is no risk that the paper will be pulled back by the paper discharge rollers and a paper jam will occur. Therefore, it is possible to feed the next sheet without waiting for the previous sheet to be discharged, thereby shortening the time when printing or the like on a plurality of sheets. In addition, the present invention does not require a one-way clutch, and can be configured only with gears, so that the accuracy of parts can be easily obtained, the operation can be stabilized, and the structure can be simplified and the cost can be reduced.

[0010] The movable gear block according to the present invention can be composed of a friction arm attached to a rotation shaft of a feed roller, and a plurality of gears held by the friction arm. The friction arm is elastically supported by the force of a spring with respect to the rotation axis of the feed roller, and is rotatable following the rotation direction of the feed roller.

In this case, the fixed gear is composed of a plurality of gears, and when the feed roller rotates in one direction, one of the plurality of gears engages with one of the fixed gears, and the feed roller and the discharge roller And an even number of gears between them. Further, when the feed roller rotates in the other direction, another one of the plurality of gears engages with the other one of the fixed gears, and an odd number of gears are provided between the feed roller and the discharge roller. To intervene.

Further, it is preferable that one of the plurality of fixed gears is provided with a flange portion, and the other fixed gear is prevented from coming off by the flange portion. According to this, it is not necessary to provide a retaining member such as a washer for each fixed gear, and the number of parts and the number of assembling steps can be reduced, and the manufacturing can be performed at lower cost.

[0013]

[Embodiment of the invention]

 FIG. 1 is an exploded perspective view of a main part of a printer 100 provided with a paper feed mechanism according to the present invention. 1 is a housing of the printer, 2 is a feed roller for feeding paper, 2a and 2b are rotating shafts of the feed roller 2, and 3 and 4 are bearings provided with roller bearings. The feed roller 2 is supported by the bearings 3 and 4 by inserting the rotating shafts 2a and 2b into the bearings 3 and 4, respectively, and attached to the housing 1 via the bearings 3 and 4. 5 is a friction arm attached to the rotation shaft 2a of the feed roller 2, 6 is a spring for elastically supporting the friction arm 5 with respect to the rotation shaft 2a, and 7 is a friction arm 5 inserted into the rotation shaft 2a. A washer that abuts one side.

Reference numeral 11 denotes a first gear that penetrates through the friction arm 5 and is press-fit into the rotating shaft 2 a of the feed roller 2, 12 denotes a second gear held by the friction arm 5, and 13 denotes a first gear that is held by the friction arm 5. This is the third gear. The movable gear block 10 is configured by the friction arm 5, the second gear 12, and the third gear 13.

Reference numeral 8 denotes a feed gear attached to the rotating shaft 2b, and reference numeral 9 denotes a spring interposed between the feed gear 8 and the bearing 4. The feed gear 8 is configured to rotate in conjunction with a motor (not shown) provided in the housing 1. The rotation of the feed gear 8 causes the feed roller 2 to rotate and feed paper. Although a pinch roller is provided to press the sheet in opposition to the feed roller 2, it is not shown here.

Reference numerals 14 to 16 denote fixed gears supported by the housing 1, 14 denotes a fourth gear, 15 denotes a fifth gear, and 16 denotes a sixth gear. The fourth gear 14 is engaged with the fifth gear 15, and the fifth gear 15 is engaged with the sixth gear 16. 19 is a washer for retaining the fifth gear 15. Reference numeral 18 denotes a paper discharge roller for discharging the paper fed by the feed roller 2, and includes a rotating shaft 18a supported by the housing 1 and a rubber ring 18b mounted on the rotating shaft 18a. Reference numeral 17 denotes a seventh gear attached to the end of the rotating shaft 18a, and the seventh gear engages with the sixth gear 16. In addition, a star wheel that feeds the sheet in opposition to the sheet discharging roller 18 is provided, but is not illustrated here.

FIG. 2 is an enlarged perspective view near the movable gear block 10. The friction arm 5 has a boomerang shape, a through hole 5a is formed in the center, and through holes 5b and 5c are formed on both sides. The boss 11a of the first gear 11 penetrates through the through-hole 5a, and the recess 11b of the boss 11a is pressed into the tip of the rotating shaft 2a of the feed roller 2 so that the first gear 11 is rotated by the rotating shaft 2a. , And rotates integrally with the feed roller 2. The shaft 12a of the second gear 12 is inserted into the through hole 5b, and the elastic hook piece 12b is engaged with the peripheral edge of the through hole 5b so that the second gear 12 is held by the friction arm 5. You. Similarly, the shaft 13a of the third gear 13 is inserted into the through hole 5c, and the third gear 13 is held by the friction arm 5 by engaging the elastic hook piece 13b with the periphery of the through hole 5c. .

In assembling, first, the hole 7a of the washer 7 is passed through the rotating shaft 2a. At this time, the washer 7 is locked by the step 2c of the rotating shaft 2a. Next, the through-hole 5a of the friction arm 5 holding the second gear 12 and the third gear 13 is inserted into the rotating shaft 2a, and then the first gear 11 in which the spring 6 is fitted around the boss 11a. Attach to the rotating shaft 2a. At this time, when the recess 11b of the first gear 11 is pressed into the tip of the rotary shaft 2a of the feed roller 2, the boss 11a penetrates the through hole 5a of the friction arm 5, and the friction arm 5 11 and sandwiched. On the other hand, a spring 6 is interposed between the first gear 11 and the friction arm 5, and by the force of the spring 6, the friction arm 5 is pressed against the washer 7 and elastically supported on the rotating shaft 2a. The feed roller 2 is rotatable following the rotation direction.

FIG. 3 shows an enlarged plan view of the fixed gear portion. As described above, the fourth gear 14 is engaged with the fifth gear 15, and the fifth gear 15 is engaged with the sixth gear 16. 14a, 15a, and 16a are shafts that rotatably support the fourth gear 14, the fifth gear 15, and the sixth gear 16, respectively. The fixed gears 14 to 16 are connected to the housing 1 via these shafts. Supported by The fifth gear 15 has a flange portion 15b, and the fourth gear 14 and the sixth gear 16 are prevented from coming off by the flange portion 15b. That is, when assembling, the fourth gear 14 and the sixth gear 16 are fitted to the shafts 14a and 16a, respectively, and then the fifth gear 15 is fitted to the shaft 15a, and then the washer is attached to the end of the shaft 15a. 19 is attached. As a result, the fifth gear 15 is prevented from coming off by the washer 19 and is supported by the shaft 15a, and the fourth gear 14 and the sixth gear 16 are prevented from coming off by the flange portion 15b of the fifth gear 15, so that the shaft 14a , 16a. With such a structure, it is not necessary to prevent the fourth gear 14 and the sixth gear 16 from coming off with a washer, and the number of parts and the number of assembling steps can be reduced.

FIG. 4 is a left side view of the printer 100 of FIG. 1, showing a state in which the paper feed mechanism 30 is incorporated in the housing 1. The first gear 11 is always engaged with each of the second gear 12 and the third gear 13. The second gear 12 can be brought into contact with and separated from the fourth gear 14. When the friction arm 5 rotates counterclockwise in FIG. 4 about the rotation shaft 2 a (FIG. 1), the fourth gear 14 rotates. 14 is engaged. Further, the third gear 13 can be brought into contact with and separated from the fifth gear 15, and engages with the fifth gear 15 when the friction arm 5 rotates clockwise in FIG. 4 around the rotation shaft 2 a. I do. The fourth gear 14 and the fifth gear 15 are always engaged, the fifth gear 15 is always engaged with the sixth gear 16, and the sixth gear 16 is always engaged with the seventh gear 17. are doing. After the rotation of the friction arm 5 and the engagement of the gear 12 or 13 with the gear 14 or the gear 15, a slip occurs between the friction arm 5 and the rotating shaft 2a. Only the rotation shaft 2a keeps rotating without rotating.

As described above, when the movable gear block 10 and the fixed gears 14 to 17 are interposed between the feed roller 2 and the paper discharge roller 18, as a result of the rotation of the feed roller 2 and the rotation of the first gear 11, The rotation is transmitted from the second gear 12 or the third gear 13 to the fourth gear 14 or the fifth gear 15, transmitted from the fifth gear 15 to the seventh gear 17 via the sixth gear 16, and Rotate.

Next, the operation of the paper feed mechanism 30 having the above configuration will be described. FIG. 5 shows the forward rotation state of the feed roller. When the feed roller 2 rotates forward, the friction arm 5 also follows this, and rotates clockwise in FIG. 5 around the rotation shaft 2a (FIG. 1), whereby the third gear 13 is shifted to the fifth gear. 15 and the second gear 12 separates from the fourth gear 14. Further, the first gear 11 rotates in the x1 direction (forward rotation direction) together with the feed roller 2, and by this rotation, the second gear 12 rotates in the x2 direction, and the third gear 13 rotates in the x3 direction. However, since the second gear 12 is separated from the fourth gear 14, the rotation of the second gear 12 is not transmitted to the fourth gear 14.

On the other hand, when the third gear 13 rotates in the x3 direction, the fifth gear 15 engaged with the third gear 13 rotates in the x5 direction. Further, the rotation of the fifth gear 15 causes the sixth gear 16 engaged therewith to rotate in the x6 direction, and the rotation of the sixth gear 16 causes the engagement of the seventh gear 16g. 17 rotates in the x7 direction. The rotation of the fifth gear 15 rotates the fourth gear 14 engaged with the fifth gear 15 in the x4 direction. However, since the fourth gear 14 is floating, the rotation is not transmitted to other gears. Thus, the rotation of the feed roller 2 is transmitted to the discharge roller 18 via the plurality of gears, and the discharge roller 18 rotates.

Here, in the case of normal rotation, the third gear 13 and the fifth gear 15 are engaged as shown in FIG. 5 by the clockwise rotation of the friction arm 5 as described above. Five (odd) gears 11, 13, 15, 16, 16 and 17 are interposed between the feed roller 2 and the discharge roller 18. As a result, the rotation directions x1 and x7 of the gear 11 and the gear 17 are the same, and the forward rotation of the feed roller 2 also causes the discharge roller 18 to rotate forward.

FIG. 6 shows a reverse rotation state of the feed roller. When the feed roller 2 rotates in the reverse direction, the friction arm 5 follows and rotates counterclockwise in FIG. 6 about the rotation shaft 2a (FIG. 1), whereby the second gear 12 The third gear 13 is separated from the fifth gear 15 while engaging with the fourth gear 14. Further, the first gear 11 rotates together with the feed roller 2 in the y1 direction (reverse rotation direction), and by this rotation, the second gear 12 rotates in the y2 direction, and the third gear 13 rotates in the y3 direction. However, since the third gear 13 is separated from the fifth gear 15, the rotation of the third gear 13 is not transmitted to the fifth gear 15.

On the other hand, when the second gear 12 rotates in the y2 direction, the fourth gear 14 engaged with the second gear 12 rotates in the y4 direction. The rotation of the fourth gear 14 causes the fifth gear 15 engaged with the fourth gear 14 to rotate in the y5 direction. Further, the rotation of the fifth gear 15 causes the sixth gear 16 engaged therewith to rotate in the y6 direction, and the rotation of the sixth gear 16 causes the engagement of the seventh gear 16 with the seventh gear 16. The gear 17 rotates in the y7 direction. Thus, the rotation of the feed roller 2 is transmitted to the discharge roller 18 via the plurality of gears, and the discharge roller 18 rotates.

Here, in the case of reverse rotation, the second gear 12 and the fourth gear 14 are engaged as shown in FIG. 6 by the rotation of the friction arm 5 in the counterclockwise direction as described above. Six (even) gears 11, 12, 14, 15, 16 and 17 are interposed between the feed roller 2 and the discharge roller 18. As a result, the rotation directions y1 and y7 of the gear 11 and the gear 17 are reversed, and the discharge roller 18 rotates forward by the reverse rotation of the feed roller 2.

As described above, the rotation direction of the friction arm 5 is changed according to the rotation direction of the feed roller 2, and the number of gears interposed between the feed roller 2 and the discharge roller 18 is switched between an even number and an odd number. Thus, the paper discharge roller 2 can always be normally rotated regardless of the rotation direction of the feed roller 2. Therefore, even if the feed roller 2 is rotated in the reverse direction in a state where the paper is not completely discharged from the paper discharge roller 18, the paper discharge roller 18 continues to rotate normally, so that the paper is not pulled back and a paper jam does not occur. . For this reason, the next sheet can be fed without waiting for the previous sheet to be discharged, and the time for printing on a plurality of sheets can be reduced. Also, since a one-way clutch is not required and the gears can be used, the precision of parts can be easily obtained, the operation can be stabilized, and the structure can be simplified and the cost can be reduced.

The present invention is not limited to only the above-described embodiment, and various other forms are conceivable. For example, the number of gears described above is merely an example, and the number of gears is not limited as long as an even number of gears and an odd number of gears can be switched. Further, in the above embodiment, the paper feed mechanism used in the printer has been described as an example, but the present invention can also be applied to the paper feed mechanism of an automatic paper feeder in a copying machine, a facsimile machine, or the like.

[0030]

[Effect of the invention]

 According to the present invention, the paper discharge roller always rotates forward regardless of the rotation direction of the feed roller, so that the next paper can be fed without waiting for the paper discharge to be completed. Time can be reduced. In addition, since it can be configured with gears alone without using a one-way clutch, the operation can be stabilized, and the structure can be simplified and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a main part of a printer according to the present invention.

FIG. 2 is an enlarged perspective view near a movable gear block.

FIG. 3 is an enlarged plan view of a fixed gear portion.

FIG. 4 is a side view of a printer incorporating a paper feed mechanism.

FIG. 5 is a view for explaining the operation of the paper feed mechanism according to the present invention at the time of normal rotation.

FIG. 6 is a view for explaining the operation of the paper feed mechanism according to the present invention at the time of reverse rotation.

FIG. 7 is a view for explaining the operation of the conventional paper feed mechanism at the time of normal rotation.

FIG. 8 is a diagram illustrating an operation of the conventional paper feed mechanism at the time of reverse rotation.

[Explanation of symbols]

 2 Feed roller 5 Friction arm 6 Spring 10 Movable gear block 11 First gear 12 Second gear 13 Third gear 14 Fourth gear 15 Fifth gear 15b Flange part 16 Sixth gear 17 Seventh gear 18 Discharge roller 30 Paper feed Mechanism 100 Printer

Claims (5)

[Utility model registration claims] A feed roller that feeds the paper; and a discharge roller that discharges the paper fed by the feed roller. The feed roller is rotated in reverse during feeding to align the leading edges of the paper. And a plurality of fixed gears between the feed roller and the discharge roller, the movable gear block transmitting rotation of the feed roller to the discharge roller. The movable gear block comprises a friction arm attached to a rotation axis of a feed roller, and a plurality of gears held by the friction arm, wherein the friction arm is arranged with respect to a rotation axis of the feed roller. The spring is elastically supported by the force of a spring, and is rotatable following the rotation direction of the feed roller. When the roller rotates in one direction, one of the plurality of gears held by the friction arm engages with one of the fixed gears, and an even number of gears are formed between the feed roller and the discharge roller. The rotation of the feed roller is transmitted to the paper discharge roller by the even number of gears, and when the feed roller rotates in the other direction, the other one of the plurality of gears held by the friction arms is An odd number of gears are interposed between the feed roller and the discharge roller by engaging with another one of the fixed gears, and the rotation of the feed roller is transmitted to the discharge roller by the odd number of gears. A printer wherein the discharge roller always rotates forward regardless of the rotation direction of the feed roller by switching the number of gears based on the rotation of the arm. A feed roller for feeding the paper, and a discharge roller for discharging the paper fed by the feed roller, the feed roller being rotated in reverse during feeding to align the leading edges of the paper. A paper feed mechanism configured to feed a sheet by rotating a feed roller in a forward direction, wherein a movable gear block and a fixed gear for transmitting rotation of the feed roller to the sheet discharge roller between the feed roller and the sheet discharge roller. When the feed roller rotates, the movable gear block rotates following the rotation direction, whereby the gear of the movable gear block engages with the fixed gear, and according to the rotation direction of the feed roller, By switching the number of gears interposed between the feed roller and the discharge roller between an even number and an odd number, the discharge roller always operates regardless of the rotation direction of the feed roller. Paper feed mechanism, characterized in that so as to forward. 3. The paper feed mechanism according to claim 2, wherein the movable gear block comprises a friction arm attached to a rotation shaft of a feed roller, and a plurality of gears held by the friction arm. A paper feed mechanism, wherein the friction arm is elastically supported by a force of a spring with respect to a rotation axis of the feed roller, and is rotatable following the rotation direction of the feed roller. 4. The paper feed mechanism according to claim 3, wherein the fixed gear comprises a plurality of gears, and when the feed roller rotates in one direction, one of the plurality of gears held by the friction arm. When one of the fixed gears is engaged with one of the fixed gears, an even number of gears are interposed between the feed roller and the discharge roller, and when the feed roller rotates in the other direction, a plurality of gears held by the friction arm are provided. A sheet feeding mechanism, wherein an odd number of gears are interposed between the feed roller and the sheet discharge roller by engaging another one of the gears with the other one of the fixed gears. 5. The paper feeding mechanism according to claim 4, wherein one of the plurality of fixed gears has a flange portion, and the other fixed gear is prevented from coming off by the flange portion. Paper feed mechanism.