JP3776785B2 - Printer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printer including an adjusting mechanism that can adjust the elastic contact force of a driven roller with respect to a driving roller in accordance with the thickness of printing paper.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a printer is provided with a conveying means comprising a driving roller and a driven roller that is elastically contacted with the driving roller and driven by the rotation of the driving roller in order to convey printing paper. The elastic contact force (friction) of the driven roller with respect to the driving roller corresponds to the thickness of each printing paper when a thin cut paper is supplied as printing paper or when a continuous continuous paper is supplied. Therefore, it is necessary to adjust the strength of the elastic contact force of the driven roller with respect to the driving roller. That is, when supplying thin cut paper, the friction of the driven roller is strongly adjusted, and when supplying thick continuous paper, this elastic contact force is weaker than when cutting paper is supplied. However, since the continuous paper uses a paper feeding tractor, the elastic contact force of the driven roller may be weak also in this respect.
[0003]
As described above, in order to adjust the strength of the friction of the driven roller in accordance with the thickness of the printing paper to be fed, conventionally, an electromagnetic solenoid is generally used. When the elastic contact force is adjusted to a desired strength, it is necessary to continue excitation by passing a current through the solenoid in order to maintain the predetermined position.
[0004]
[Problems to be solved by the invention]
However, in the conventional solenoid system, the excited state must always be maintained even after adjusting the strength of the elastic force of the driven roller, which is not preferable in terms of power saving.
[0005]
Accordingly, an object of the present invention is to provide a printer that is suitable for power saving by maintaining the predetermined position even in a non-excited state after the driven roller is adjusted to a predetermined elastic contact strength.
[0006]
The printer according to the present invention is characterized in that, in a printer that sandwiches and conveys paper between a rotationally driven driving roller and a driven roller that elastically contacts the driving roller, the driven roller is configured to have an elastic contact force to the driving roller by an adjustment mechanism an adjustable, the adjusting mechanism, the through a spring member for applying the elastic contact force to the drive roller to the driven roller, a drive member for varying the deformation amount of the spring member, a gear train a drive member and a drive motor for reciprocating said although the gear train to allow rotation in one direction of the gear train, the one-way clutch to prevent rotation in the other direction of the gear wheel train The toothed wheel train is fixed in a direction opposite to the direction in which the drive motor drives the toothed wheel train .
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, a paper guide 10 is installed in the printer, and two guide shafts are disposed between both side plates 20 above the paper guide. (Only one is shown) 30 is installed, and a carriage 40 is slidably provided on the guide shaft, and a print head 50 is mounted on the carriage. A paper guide 51 is attached to the nose of the print head 50, and predetermined printing is performed when a print wire inserted in the nose collides with a platen 60 positioned below the paper wire. A paper feed tray 70 for supplying cut paper is installed at the left end of the printer, and a tractor 80 for supplying continuous paper is installed below the paper feed tray. A lid 71 is provided at the front end of the cut paper feed tray 70 so as to be swingable upward. When the continuous paper is supplied by the tractor 80, the continuous paper to be transported has the lid upward. The sheet is pushed up and conveyed between the print head 50 and the platen 60.
[0008]
On both sides of the printing unit comprising the print head 50 and the platen 60, that is, on the upstream side and the downstream side, conveying means for cut paper or continuous paper is provided. The conveying means includes a driving roller 1 and a driven roller 2 on the downstream side, and a driving roller 11 and a driven roller 21 on the upstream side. The cut paper or continuous paper is sandwiched and conveyed by the driving rollers 1 and 11 and the driven rollers 2 and 21. Both the drive rollers 1 and 11 are provided below the paper guide 10 in close proximity thereto, and are driven to rotate by a reversible drive motor (not shown). 21 is elastically contacted and is driven to rotate by the driving roller.
[0009]
Therefore, the configuration of the adjusting mechanism that adjusts the elastic contact force of the driven rollers 2 and 21, which is a feature of the present invention, will be described. The driven rollers 2 and 21 are provided with separate independent elastic contact force adjustment mechanisms. This adjusting mechanism includes spring members 31 and 61 that give the driven rollers 2 and 21 an elastic contact force to the drive rollers 1 and 11 and drive members 25, 26, 27, 47, and 48 that make the deformation amount of the spring members variable. , 49, and pulse drive rotors M1, M2 that rotate in one direction to drive this drive member through toothed wheel trains 21a, 22, 23, 24, 41, 42, 43, 44.
[0010]
First, a description will be given of the tooth wheel train in the mechanism for adjusting the elastic force of the driven roller 2 positioned on the downstream side. A crank gear 25 is meshed with a gear 24 that is coaxially attached to the small gear, is fixed, and rotates together with the small gear. Next, a description will be given of the configuration of the drive member that allows the amount of deformation of the spring member to be variable. One pin 25a projects from the outer periphery of the crank gear 25, and the lower end of the arm 26 is provided on this pin 25a. It is pivotally supported. A pin 26 a is provided at the upper end of the arm 26, and this pin 26 a can reciprocate in a long hole (guide hole) 27 that is fixedly provided in the side plate 20. One end of a spring spring 31 that is a spring member is engaged with the pin 26a, and the other end of the spring spring 31 is engaged with one end of a lever 32 for adjusting the elastic contact force. The lever 32 can swing around a pin 33, and a locking groove cut into the lower surface of the lever 32 engages with the shaft 34 of the driven roller 2 to apply a spring force to the driven roller 2. This is pressed against the surface of the drive roller 1.
[0011]
By the way, it is allowed to rotate this gear in one direction between one gear 24 in the gear train for transmitting the power of the drive motor M1 and its support shaft 23, but in the other direction. It has a one-way clutch that prevents it from rotating. Further, a position detection device 28 is installed below the crank gear 25, and this position detection device includes a light projecting element and a light receiving element provided opposite to each other. The light beam from the light projecting element is blocked when the lower end of the arm 26 crosses, and this blocked state is detected and set as a reference position in the friction adjustment mechanism of the driven roller 2.
[0012]
Therefore, when supplying continuous paper from the tractor 80 to the printer in FIG. 1, it is necessary to adjust the elastic contact force of the driven roller 2 to be as weak as possible. Therefore, the drive motor M1 is driven to rotate, the crank gear 25 is rotated through the toothed wheel trains 21a, 22, 23, and 24, and the arm 26 is moved downward in the long hole 27. As shown in FIG. When the lower end of the arm crosses between the light projecting element and the light receiving element of the position detection device 28, the rotation of the drive motor M1 is stopped. At this time, since the pin 26a at the upper end of the arm 26 is at the lower end position of the long hole 27, the spring spring 31 as the tension coil spring is in the most contracted state, and the elastic contact force by the lever 32 is in the weakest state. Therefore, the elastic contact force of the driven roller 2 with respect to the driving roller 1, that is, the friction is the weakest.
[0013]
Next, when the cut sheet is supplied from the paper feed tray 70 to the printer, the drive motor M1 is driven until the lower end portion of the arm 26 crosses between the light projecting element and the light receiving element of the position detecting device 28, and this position is Is rotated by supplying a predetermined number of pulses to the drive motor M1, and the crank gear 25 is rotated clockwise through the tooth wheel trains 21a, 22, 23, and 24. Therefore, the arm 26 rises from the state of FIG. 1 to the upper end position of the long hole 27 as shown in FIG. 2, so that the spring spring 31 is pulled and the elastic force of the driven roller 2 against the driving roller 1 via the lever 32. The contact force is maximized.
[0014]
At the same time, the return force of the spring force of the spring spring 31 to the original position tries to rotate the crank gear 25 and the gear 24 via the arm 26. However, since a one-way clutch is provided between the gear 24 and the support shaft 23, even if the drive motor M1 is turned off and no static torque is generated in a non-excited state, the toothed wheel train 21a, 22, 23 and 24 are held at fixed positions.
[0015]
Next, the configuration of the mechanism for adjusting the elastic contact force of the driven roller 21 of the conveying means located on the upstream side of the printing unit composed of the print head 50 and the platen 60 will be described. Most of the configurations are substantially the same as those on the downstream side described above, and a spring member, a drive member that can vary the amount of deformation of the spring member, and the drive member are driven via a toothed wheel train. It consists of a drive motor. First, the gear wheel train in this adjustment mechanism will be described. A gear 42 meshes with a drive pinion 41 of one drive motor M2, and a gear 43 that is coaxially attached to this gear and is fixedly interlocked and rotated. The intermediate gear 44 meshes with the small gear 45, and the intermediate gear 44 is coaxially mounted with the small gear 45. Next, the structure of the drive member that makes the deformation amount of the spring member variable will be described. One pin 47a protrudes near the outer periphery of the crank gear 47, and the lower end of the arm 48 rotates on this pin. It is pivotally supported. A pin 48 a is provided at the upper end portion of the arm 48, and the pin 48 a can move in a slightly bent long hole 49 fixedly provided on the side plate 20. One end of a spring member, for example, a torsion coil spring 61, is locked to the pin 48a. The torsion coil spring hangs around a pin 63 that rotatably supports a lever 62 for adjusting the elastic contact force. The other end is locked to the lever 62. The lever 62 can swing around a pin 63, and a locking groove cut into the lower surface of the lever 62 engages with the shaft 64 of the driven roller 21, and biases the lever 62 with a spring force. And press this.
[0016]
By the way, one gear 46 in the gear train mechanism for power transmission of the drive motor M2 rotates the gear 46 in one direction between the support shaft 45 and the gear 24 as described above. Is provided with a one-way clutch that allows but prevents rotation in the other direction.
[0017]
Further, a position detection device 90 is installed below the crank gear 47, and the structure of this position detection device is substantially the same as the configuration of the position detection device described above. An optical element and a light receiving element are provided, and a light beam from the light projecting element is blocked by the lower end of the arm 48 crossing between both elements. This blocked state is a friction of the driven roller 21. The reference position in the adjustment mechanism.
[0018]
Therefore, the adjustment operation of the adjustment mechanism of the elastic contact force of the driven roller 21 of the conveying means located on the upstream side of the printing unit composed of the print head 50 and the platen 60 will be described. In FIG. 1, when supplying continuous paper from the tractor 80 to the printer, it is necessary to adjust the elastic contact force of the driven roller 21 to the weakest. Therefore, the drive motor M2 is driven to rotate, the crank gear 47 is rotated via the tooth wheel trains 41, 42, 43, 44, 45, 46, and the arm 48 is moved up and down, as shown in FIG. When the lower end crosses between the light projecting element and the light receiving element of the position detecting device 90, the rotation of the drive motor M2 is stopped. At this time, since the pin 48a at the upper end of the arm 48 is located at the lower end position of the long hole 49, the torsion coil spring 61 is in the most open state, and the pressing force by the lever 62 is in the weakest state. The pressing force of the roller 21 against the driving roller 11, that is, the friction is the weakest.
[0019]
Next, when the cut sheet is supplied from the paper feed tray 70 to the printer, the drive motor M2 is driven until the lower end of the arm 48 crosses between the light projecting element and the light receiving element of the position detecting device 90, and this position is The drive motor M2 is rotationally driven by supplying a predetermined number of pulses to the drive motor M2 with reference to, and the crank gear 47 is rotated clockwise via the tooth wheel trains 41, 42, 43, 44, 45, 46. . Therefore, the pin 48 a of the arm 48 rises from the state of FIG. 1 to the upper end position of the long hole 49 as shown in FIG. 2, so that the opening angle of the torsion spring 61 is narrowed and the driven roller 21 is connected via the lever 62. The friction with respect to the driving roller 11 is maximized.
[0020]
At the same time, the return force to the original position of the spring force of the torsion coil spring 61 tries to rotate the crank gear 47 and the gear 46 via the arm 48. However, since a one-way clutch is provided between the gear 46 and the support shaft 45, even if the drive motor M2 is turned off and no stationary torque is generated due to de-energization, the tooth wheel trains 41, 42 are provided. , 43, 44, 45, 46 are held in a fixed position.
[0021]
In the embodiment described above, the friction of the driven rollers 2 and 21 is the maximum and the minimum, but the number of pulses supplied to the drive motors M1 and M2 is adjusted and rotated to adjust the friction in multiple stages. Of course, it can be controlled. That is, the number of pulses can be adjusted to set the friction appropriately. In this case, each time the friction is adjusted, the drive motors M1 and M2 are driven until the lower ends of the arms 26 and 48 cross between the light projecting element and the light receiving element of the position detection devices 28 and 90, and the drive is performed based on this position. If a predetermined pulse is supplied to the motors M1 and M2, variations in friction can be prevented.
[0022]
In the above-described embodiment, the driving force of the driving motors M1 and M2 is a link mechanism using a toothed wheel train and a crank gear or an arm. However, a cam mechanism or the like can be appropriately applied instead of the link mechanism. In addition, a drive circuit for driving the drive motors M1 and M2 is usually required for each motor. However, according to the embodiment of the present invention, one drive circuit is sufficient because it can be sequentially set.
[0023]
【The invention's effect】
According to the present invention, the tooth wheel train is held in a predetermined position by the one-way clutch even if the drive motor is turned off and the excitation is stopped after the elastic contact force of the driven roller is set to adapt to the sheet thickness. Therefore, it is extremely preferable in terms of power saving.
[Brief description of the drawings]
FIG. 1 is a front view of an adjustment mechanism showing a state where the elastic contact force of a driven roller is the weakest.
FIG. 2 is a front view of the adjustment mechanism showing a state where the elastic contact force of the driven roller is the strongest.
[Explanation of symbols]
1, 11 Drive roller 2, 21 Drive roller 31, 61 Spring material 25 Drive member (crank gear)
25a Drive member (pin)
26 Drive member (arm)
26a Drive member (pin)
27 Drive member (long hole)
21a Tooth wheel train (drive kana)
22 tooth wheel train (gear)
23 Support shaft 41 Tooth wheel train (drive kana)
42 tooth wheel train (gear)
43 Tooth wheel train (gear)
44 tooth wheel train (gear)
45 Support shaft 46 Tooth wheel train (gear)
47 Drive member (crank gear)
47a Drive member (pin)
48 Drive member (arm)
48a Drive member (pin)
49 Drive member (long hole)
M1 drive motor M2 drive motor

Claims (1)

A printer that sandwiches and conveys paper between a rotationally driven drive roller and a driven roller that elastically contacts the drive roller,
The driven roller can adjust the elastic contact force to the drive roller by an adjustment mechanism,
The adjustment mechanism includes a spring member that imparts elastic force to the driven roller to the driven roller;
A drive member that can vary the amount of deformation of the spring member ;
A drive motor that reciprocates the drive member via a tooth wheel train,
Wherein at the gear train to allow rotation in one direction of the gear train, the one-way clutch to prevent rotation in the other direction of the gear train provided, the drive motor drives the gear train A printer characterized in that the tooth wheel train is fixed in a direction opposite to the direction .

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