JPH07276720A - Paper feeder - Google Patents

Abstract

PURPOSE:To provide a printer wherein when an abnormal burden is applied on recording paper, a release means is automatically actuated to prevent a paper jam previously, step-out of a motor and damage of a feed hole of the recording paper are prevented from occurring, and paper can be certainly fed. CONSTITUTION:A direction wherein torque of a stepping motor operates is the arrow A direction wherein a release lever is separated from a gear 23. In order to engage a reducing gear 24 with a paper-feeding gear 23, the release lever 40 is energized in the arrow B direction with a lever spring 48 of less force than the torque of the motor 25.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Printers used for issuing slips and the like often use fanfold paper having feed holes on both sides, and pins of a sprocket wheel are engaged with these feed holes. By doing so, the fanfold paper is sequentially fed to the platen.

Therefore, in this type of printer, the fanfold paper is wrapped around the sprocket wheel, and it is necessary to rotate the sprocket wheel when pulling out the paper or manually aligning the paper. However, the sprocket wheel is in power transmission with the motor, and due to the detent torque of the motor, it does not rotate with a light force from the outside. Therefore, a means (release means) for disconnecting power transmission has been proposed. The operator makes the sprocket wheel idle by this release means, pulls out the paper, or manually rotates the sprocket wheel to adjust the print position. This release means includes a method of releasing the meshing of the gear train with a lever and a method of disconnecting the power transmission with a clutch mechanism.
Although various proposals have been made, the common point is that the operator operates the sprocket wheel, and unless the operator operates it, the sprocket wheel is always in power transmission with the motor.

[0004]

In the above-mentioned conventional example,
Even if the fan-folded paper supply unit receives some external force during the paper feeding operation of the printer and the paper feeding is stopped, the sprocket wheel that is transmitted from the motor tries to rotate. . At this time,
If the torque of the motor is large, the sprocket wheel will rotate forcibly and the sprocket pin will break the feed hole, causing a paper jam problem. Also, if the motor torque is small, the motor will step out and paper feed pitch failure,
If it is worse, it is inconvenient that the voucher cannot be issued.

Further, in friction printers other than the above-mentioned conventional example, a rubber roller is generally used as a paper feed roller. However, when the paper feed roller rotates while the paper is stopped, the friction coefficient of the rubber surface decreases. However, there is a problem that the paper feeding force is reduced.

[0006] These inconveniences are caused by the abnormal usage of stopping the paper feeding at the supply section, and the paper supply section and the paper path should be kept within a predetermined allowable load of the printer. If it does, it does not cause a problem, and so far it was not recognized as a big problem. However, in recent years, there has been an increasing demand for fool-proofing and maintenance-free, and there is a demand for a printer that does not malfunction even if it is used in any wrong manner, or that detects and reports an abnormality.

The present invention has been made in view of the above problems, and an object thereof is to automatically perform recording even when the recording paper is stopped by some external force. It is another object of the present invention to provide a paper feeding device for a new printer in which the release means does not operate, the gear train is disengaged, and the sprocket pin does not break the feed hole.

[0008]

In order to solve the above problems, a paper feeding device of the present invention is a paper feeding device for transmitting power from a motor to a paper feeding shaft through a gear train, and a rotating lever member. , A transmission gear that is loosely inserted into the shaft provided on the lever member, a paper feed gear that meshes with the transmission gear and transmits power to the paper feed shaft, and a lever member is attached in the direction in which the transmission gear meshes with the paper feed gear. And a biasing means for biasing.

Further, it is characterized in that detection means for detecting the movement of the lever member is provided during the operation of the printer.

Further, the lever member is characterized in that the rotation fulcrum is a burring hole of the frame member in which the shaft of the gear for driving the transmission gear is arranged.

[0011]

The transmission gear receives the force of the biasing member and meshes with the paper feed gear. Without the biasing member, the transmission gear cannot transmit power to the paper feed gear. Therefore, when a large force is applied to the recording paper from the outside by the urging means and the paper feed is forcibly stopped, the transmission gear and the paper feed gear rotate in the direction of separating from each other.

Further, since the center of rotation of the lever member and the center of the motor gear coincide with each other, the center-to-center distance between the transmission gear and the motor gear arranged on the lever member remains the same even if the lever member rotates. It remains constant.

[0013]

EXAMPLES Now, the examples shown below will be described.

Each of the drawings shows an embodiment of the present invention. First, the overall construction of the printer will be described with reference to FIG.

This printer has a main frame 1 formed by bending a sheet metal into a U-shape, a platen 3 fixed so as to be suspended between the left and right side plates 2 and 2, and the platen 3 as a boundary. The printing unit 10 assembled in half,
It is composed of the paper feed unit 20 assembled in the other half.

The printing unit 10 described above includes the platen 3
A carriage (not shown) that is guided by a guide rod 11 that is mounted parallel to the carriage and a DC brush motor 13 that drives the carriage.
The carriage that carries the DC is connected to a part of the timing belt 18 and is connected to the DC through a series of intermediate gears 15 ...
A pulley 16 driven by a brush motor 13 is configured to travel along the surface of the platen 3 at a required speed.

On the other hand, the paper feed unit 20 described above
As shown in FIGS. 1 and 2, the sub-frame 4 bent in a U-shape carries all members related to paper feeding except the motor as one unit. As shown in FIG. 3, it is attached by being fixed to the platen 3 rear surface side of the main frame 1. The paper feeding unit 20 is roughly classified into a paper guiding mechanism, a sprocket driving mechanism, a motor position adjusting mechanism, a release mechanism,
And a manual paper feed mechanism.

The paper guide mechanism will be described below. The paper guide mechanism includes a paper feed roller 21 having a function as a guide roll, a fixed paper guide member 30 that supports the central portion of the fanfold paper in the width direction, and the fixed paper guide member 30 which is disposed on both sides of the fixed paper guide member 30. And the bistable spring 3
It is composed of a pair of left and right movable paper guide members 35, 35 which are urged by 9, 39 to move and displace to positions corresponding to paper widths of 3 inches and 3.5 inches. The paper guide members 35, 35 are guided by the guide rods 36 suspended on the side plates 5, 5 of the sub-frame 4 and can move in the width direction. In addition, the paper feed shaft 22 having a rectangular cross section disposed inside the paper guide.
Holds the paper feed roller 21 in the center and is slidable in the axial direction on both sides of the paper feed roller 21.
6 and 46 are held loosely. When the paper guides 35, 35 are moved and displaced, the sprocket wheels 46, 46 are also engaged with the paper guide members 35, 35 and moved and displaced to positions corresponding to the paper widths of 3 inches and 3.5 inches. In FIG.
When the paper guide members 35, 35 are moved in the direction of arrow A, that is, inward, the paper guide members 35, 35 come into contact with the fixed paper guide member 30 and become a paper guide for 3 inch paper.
When 5, 5 are moved in the direction of arrow B, that is, outward, the paper guiding members 35, 35 come into contact with the inner surfaces of the side plates 5, 5 of the sub-frame 4 to provide a paper guide for 3.5 inch paper. In this way, this printer can handle two types of paper width.

Next, the sprocket drive mechanism will be described with reference to FIG. A sprocket driving power source is a stepping motor 25, and a motor gear 26 is fixed to a motor shaft 29. The power is transmitted from the motor gear 26 through the reduction gear 24 to the paper feed gear 23 fixed to the paper feed shaft 22. The stepping motor 25 is not fixed to the paper feeding unit 20, but is fixed to the side plate 2 of the main frame 1, while the reduction gear 24 is arranged on the release lever 40 of the paper feeding unit 20, When the stepping motor 25 is fixed, it is necessary to match the axial distance between the motor gear 26 and the reduction gear 24 so that the meshing of the gears has an appropriate backlash. This inter-axis distance can be adjusted by a motor position adjusting plate 27 described later. This printer uses separate motors for the print head feed mechanism and paper feed mechanism, and because the mechanism is independent,
The paper can be fed at any position of the print head 12 except during printing.

Next, the motor position adjusting mechanism will be described with reference to FIGS. 1, 5 and 6. In this printer, a burring hole 6 having a hole slightly larger than the diameter of the motor shaft 29 is provided on the side plate 5 of the sub-frame 4 so as to project to the outside of the side plate 5. When the motor shaft 29 is inserted in the center of the burring hole 6, the motor gear 26 and the reduction gear 24
It is set so that the axis distance between and is optimal. The motor shaft 29 of the stepping motor 25 projects longer than the motor gear 26. A motor position adjusting plate 27 is attached to the inside of the side plate 5 by snap fitting on the sub-frame 4, and can be slid in a certain range in the A and B directions. The motor position adjusting plate 27 is provided with a hole 28 into which the protruding portion of the motor shaft 29 is inserted. The hole 28 has an engaging portion C having the same diameter as the motor shaft 29 and a D portion having a diameter larger than the motor shaft 29. There is. FIG. 5 shows the motor position adjusting plate 2.
7 is in the state of being pulled up in the direction of the arrow B to the nearest degree. At this position (hereinafter referred to as a mounting position), the engagement portion C is set to be at the center of the burring hole 6. Further, a part of the motor position adjusting plate 27 projects outward from the side plate 5 of the printer. When the stepping motor 25 is fixed to the side plate 2 of the main frame 1 by inserting the motor shaft 29 into the hole 28 so as to contact the engaging portion C at the mounting position, the motor shaft 29 is positioned at the center of the burring hole 6. Motor gear 2
6 and the reduction gear 24 have an optimum center distance. The motor shaft 29 of the stepping motor 25 is a motor gear 26.
Since it protrudes longer than
It is easy to match with.

In this state, the stepping motor 2
When 5 is rotated, the motor shaft 29 and the motor position adjusting plate 2
Since 7 is in contact, the transfer torque is reduced due to the friction load. Therefore, in this printer, after fixing the stepping motor 25, as shown in FIG. 6, when the motor position adjusting plate is pushed down in the direction of arrow A, the motor shaft 29 enters the D portion of the hole 28, and the motor position adjusting plate 27. Is designed so as not to escape from the motor shaft 29 and become a rotational load of the motor (hereinafter referred to as a release position). In the release position, the motor position adjusting plate 27 is located inside the outer shape of the side plate 5 of the printer and does not interfere. Therefore, the operator does not accidentally touch and load the motor. Also,
The advantage of the motor position adjustment mechanism of this printer is that
The motor position adjusting plate 27 slides and is attached to the printer body without being separated from the printer body. Therefore, even when a serviceman or the like attaches and detaches the stepping motor 25 at the time of maintenance after product shipment, the motor position adjustment plate 27 can be attached. There is no need to use a jig, move this motor position adjustment plate 27,
It suffices to mount the stepping motor 25, and the backlash of the gear train does not change.

Next, the release mechanism, which is a feature of the present invention, will be described with reference to FIG. As described above, the burring hole 6 is formed in the side plate 5 of the sub-frame 4. The release lever 40 has a shaft 4
2 is provided perpendicular to the release lever 40, and the shaft 4
A reduction gear 24 is rotatably loosely inserted in the shaft 2.
The length of the shaft 42 is such that the tip of the shaft 42 is the main frame 1 when the paper guide unit 20 is fixed to the main frame 1.
The length is set so that it is located at the very end of the inner surface of the side plate 2, and is set to a value somewhat longer than the thickness of the reduction gear 24, even if the variation in parts is taken into consideration. Further, the release lever 40 is provided with a fulcrum hole 41 of such a size that the protruding portion of the burring hole 6 can be exactly inserted therein. The release lever 40 is rotatably supported by the sub-frame 4 with a fulcrum hole 41 fitted in a protruding portion of the burring hole 6. When the paper feed unit 20 is fixed to the main frame 1, the release lever 40 and the reduction gear 24 are sandwiched between the side plates 2 and 5 and cannot be separated from the paper guide unit 20.

As described above, the burring hole 6 has a structure in which the protruding motor shaft 29 of the stepping motor 25 is inserted. When the stepping motor 25 is accurately fixed using the motor position adjusting plate 27, the release lever 40 is released. The center of rotation of is coincident with the center of the motor gear 26.
That is, even if the release lever 40 rotates, the center distance between the reduction gear 24 and the motor gear 26 is constant, and there is an appropriate backlash so that the motor gear 26 and the reduction gear 24 are kept in a meshed state. Be drunk The forward rotation direction of paper feed is the direction of arrow C of the motor gear 26, which means that it acts on the release lever 40 in the direction of arrow A, that is, the reduction gear 24 and the paper feed gear 23 separate. Direction. Therefore, a lever spring 48, which is a tension coil spring, is hooked on the release lever 40 and the sub-frame 4, and the release lever 40 is pulled in the direction of arrow B to hold the space between the reduction gear 24 and the paper feed gear 23. Each gear meshes with each other. Here, it should be noted that the inter-axis holding force by the lever spring 48 is larger than the inter-axis holding force required to transmit the paper feeding force, and the stepping motor 25 rotates in the forward direction. This is because it is set to be smaller than the force that acts in the direction of separating the shafts due to the drive torque of the motor. Therefore, when the motor rotates forward, the stepping motor 25
That is, the rotation force of the lever spring 48 is not transmitted to the paper feed gear 23 as it is, but is adjusted by the spring force of the lever spring 48 so as to be a predetermined force smaller than the rotation force of the stepping motor 25. A stopper portion 7 of the release lever 40 projects from the side plate 5 of the sub-frame 4, and the release lever 40 hits the stopper portion 7 at all times so that the axial distance between the paper feed gear 23 and the reduction gear 24 has an optimum value. Is set to.

The operator pushes the release lever 40 in the direction of arrow A.
When pushed in the direction, the paper feed gear 23 and the reduction gear 24 are disengaged from each other. This state is called a release state. In the released state, the sprocket wheels 46, 46 can freely rotate in forward and reverse directions. Therefore, when removing the paper, the fanfold paper is pulled out in either the forward or reverse direction with the release state. Since this release mechanism does not have a lock mechanism, the operator must continue to press the release lever 40 in order to maintain the release state. Also,
This release mechanism is characterized in that the gear train is automatically disengaged when the paper feed is stopped due to some external force acting on the fanfold paper. Wheel 46,46
Is forcibly rotated, and the sprocket pin 47 does not break the feed hole of the fanfold paper. This principle will be described below.

In the forward direction of paper feeding, the stepping motor 2
When the rotation lever 5 is rotated, the direction in which the rotational force acts on the release lever 40 is the direction of arrow A, that is, the release lever 4
A force acts in the direction in which 0 separates from the paper feed gear 23. Therefore, the lever spring 48 pulls the release lever 40 in the direction of the arrow B to engage the reduction gear 24 on the release lever 40 with the paper feed gear 23, but a force larger than that of the lever spring 48 is applied from the outside to the fanfold. If the paper is caught and the fanfold paper feed is stopped,
The reduction gear 24 cannot rotate the paper feed gear 23. On the other hand, since the rotating force of the stepping motor 25 is larger than that of the lever spring 48, the motor gear 26 tends to rotate even if the lever spring 48 is slightly pulled. As a result, the release lever 40 rotates in the direction of arrow A, the paper feed gear 23 and the reduction gear 24 disengage from each other, and the reduction gear 24 idles. Therefore, the sprocket wheel 4
6,46 will not rotate and will not tear the fanfold paper. At this time, the paper feed gear 23 and the reduction gear 24 generate rattling noises and jumping noises to notify the operator of the abnormality.

As described above, according to the present invention, the release mechanism automatically operates when the fan-folded paper is applied with an abnormal force and the paper feed is stopped. By the way, if you do not break the feed hole of the fanfold paper, and if you do not use such a mechanism, if the torque of the motor is low, if the fanfold paper is loaded, Step out, the sprocket wheel will stop spinning. However, the motor torque greatly varies depending on conditions such as the voltage applied to the motor, the environmental temperature, and the control method of the motor. Therefore, even with the same paper load, the motor loses synchronization under certain conditions, but loses under certain conditions. It can happen that it doesn't work. In that respect, the tension coil spring used in this example has a relatively stable spring force without affecting the voltage applied to the motor, the environmental temperature, and the motor control method, and stabilizes the paper load on which the release mechanism operates. Can be set.

As described above, this release mechanism is
In particular, this is an effective technique for a printer using fanfold paper having a paper feed hole, but is not necessarily limited to a printer using fanfold paper. For example, in a friction feed printer, the recording paper is wrapped around a rubber paper feed roller to feed the paper.
When external force is applied to the recording paper and the paper feed roller is forcibly rotated when the paper feed is stopped, the recording paper and the surface of the paper feed roller slip, and the friction coefficient of the paper feed roller surface is significantly reduced. Even after removing the external force applied to the paper, the paper may not be fed. However, when the release mechanism of the present invention is used, when the recording paper is stopped, the rotation of the paper feed roller also stops, so that the surface deterioration of the paper feed roller can be prevented and the paper feed failure can be prevented. As described above, the present invention can be widely applied to a paper feeding mechanism having a mechanism for disconnecting transmission of a gear train.

If a micro switch or the like is provided in the moving portion of the release lever 40 and the movement of the release lever 40 is detected, it is possible to detect that the paper cannot be fed normally, and an error occurs. It is possible to respond by displaying it and stopping the stepping motor 25. Further, if this release mechanism is used together with a manual paper feeding mechanism described later, the operator can adjust the print position.

Next, the manual paper feed mechanism will be described with reference to FIG. The release mechanism is arranged on the right side of the printer body, whereas the manual paper feed mechanism is arranged on the opposite left side. A knob gear 45 is rotatably supported on a shaft provided on the side plate 5 of the sub-frame 4.
The knob gear 45 meshes with the second transmission gear 44 that is rotatably supported by another shaft provided on the side plate of the subframe 4, and further,
The second transmission gear 44 meshes with the first transmission gear 43 fixed to the paper feed shaft 22. In order to manually feed the paper, the release lever 40 is pushed in the direction of arrow A to be in the release state, and the knob gear 45 is turned. Unless in the release state, the knob gear 45 cannot be turned with a light force due to the detent torque of the stepping motor 25. The minimum pitch for manual paper feed is the feed amount for one tooth of the paper feed gear 23.

[0030]

As described above, according to the present invention, when a large load is applied to the paper and the paper feeding is stopped, the lever member is rotated by the rotational force of the motor, and the meshing of the gear train is disengaged. , Since the power transmission from the motor is cut off, the paper feed shaft will not be forced to rotate, and in the case of friction feed, the surface deterioration of the feed roller can be prevented, or the fanfold paper In case of pin feed,
Breaking the feed hole of the fanfold paper is eliminated, and damage to the sprocket pin can be prevented.

Further, in the conventional printer, even if the paper is caught in the paper path, as long as there is the motor torque, the paper is forcibly fed, so that the paper is easily jammed. If the load becomes, the paper feed driving force is cut off, which is effective in preventing paper jam.

Further, if a detecting means for detecting the movement of the lever member is provided, it can be understood that the paper feeding is stopped, and it is possible to take measures such as stopping the motor. Further, if the lever member is configured to rotate, the center distance between the transmission gear arranged on the lever member and the gear that meshes with the lever member becomes difficult to stabilize, but the motor gear is arranged at the rotation fulcrum of the lever member. With this configuration, even if the lever member rotates, the center distance between the motor gear and the transmission gear arranged on the lever member does not change, so the transmission efficiency does not change and the load on the motor does not change. The motor current can be reduced without increasing the current.

Further, since the lever member which is biased by the biasing member is positioned by the hitting portion, the distance between the centers of the transmission gear and the paper feed gear is stable, and the gear is reliably transmitted without damage to the tooth tips. Therefore, the reliability is greatly improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a paper feeding unit of a printer showing an embodiment of the present invention as seen from the rear.

FIG. 2 is a perspective view of the top paper feeding unit according to the embodiment of the present invention as seen from the front.

FIG. 3 is a perspective view showing a state in which the paper feeding unit according to the embodiment of the present invention is attached to the printer body, as viewed from the rear.

FIG. 4 is an exploded perspective view of a main part of a sprocket drive mechanism of a printer according to an embodiment of the present invention.

FIG. 5 is a side view showing the motor position adjusting mechanism of the printer according to the embodiment of the present invention, and is an explanatory view in which the motor position adjusting plate is pulled up.

FIG. 6 is a side view showing a motor position adjusting mechanism of the printer according to the embodiment of the present invention, and an explanatory view in which the motor position adjusting plate is pushed down.

FIG. 7 is a perspective view of a release mechanism of the printer according to the embodiment of the present invention.

FIG. 8 is a perspective view of a manual feeding mechanism of the printer according to the embodiment of the invention.

FIG. 9 is a top view showing the overall appearance of the printer of one embodiment of the present invention.

[Explanation of symbols]

 1 Main Frame 4 Sub Frame 6 Burring Hole 7 Stopper Section 10 Printing Unit 20 Paper Feed Unit 21 Paper Feed Roller 22 Paper Feed Shaft 26 Motor Gear 29 Motor Shaft 30 Fixed Paper Guide Member 35 Movable Paper Guide Member 40 Release Lever 41 Support Point Hole 45 Knob gear 46 Sprocket wheel 48 Lever spring

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masahiko Yamada 3-3-5 Yamato, Suwa City, Nagano Seiko Epson Corporation

Claims (3)

[Claims] 1. A paper feeding device for transmitting power from a motor to a paper feeding shaft via a gear train, a rotating lever member, and a transmission gear loosely inserted into a shaft provided on the lever member. A paper feed gear that meshes with the transmission gear and transmits power to the paper feed shaft; and a biasing unit that biases the lever member in a direction in which the transmission gear meshes with the paper feed gear. Paper feeding device. 2. The paper feeding device according to claim 1, further comprising detection means for detecting movement of the lever member during operation of the printer. 3. The paper feeding device according to claim 1, wherein the lever member is a burring hole of a frame member in which a rotation fulcrum is arranged with a shaft of a gear that drives the transmission gear.