The invention relates to a printer unit having a cutter mechanism for cutting continuous paper such as rolled paper, and a printing apparatus incorporating such a printer unit.
In the related art, one type of printing apparatus is known that includes a cutter mechanism for automatically cutting the paper to separate a printed portion from the rolled paper after printing. In order to reduce margins of the paper, the printing apparatus of this type preferably has a print head and a cutter mechanism, which are positioned as closely to each other as possible. To this end, in many printing apparatuses, the cutter mechanism is placed in an overlapping manner downstream of the print head.
Portable devices and multi-processing systems, which have features of printing apparatus(es), have recently achieved widespread use. In a device of this type, restrictions are imposed on an integration space of a printer unit including a print head and a cutter mechanism. Particularly in the case of a portable device, the overall thickness of the device is determined by the thickness of the printer unit. Hence, strong demand exists for reducing the size, or slimming of the printer unit.
However, in the case of the related-art printer unit, a cutter driving motor and a cutter driving mechanism are built into the cutter mechanism (cutter unit), and the cutter mechanism and the print head (head unit) are arranged in an overlapping manner, thus posing limitations on slimming of the printer unit.
It is therefore an object of the invention to provide a slimmed printer unit while a print head and a cutter mechanism are arranged in the overlapping manner, and which enables a reduction in the number of parts and simplification of a control circuit by obviating a motor dedicated for a cutter.
It is also an object of the invention to provide a printing apparatus incorporating such a printer unit.
In order to achieve the above objects, according to the invention, there is provided a printer unit, comprising:
In such a configuration, since the cutter driving mechanism is placed to utilize a back space behind the print head, the printer unit can be slimmed although the print head and the cutter mechanism are arranged in the overlapping manner. Further, a motor specifically designed for use with a cutter is obviated, thereby enabling a reduction in the number of parts and simplification of a control circuit.
Preferably, the cutter driving mechanism includes: a worm, extending parallel with a support axis of the paper feeding roller and a rotation axis of the motor, and rotated by the driving force of the motor; and a worm wheel, which meshes with the worm to transmit the driving force to the cutter mechanism.
In such a configuration, the driving force of the motor can be supplied to the paper feeding roller and the cutter driving mechanism by use of a simple gear mechanism while making the cutter mechanism compact.
Here, the cutter mechanism may include a movable blade formed with an elongated hole. The worm wheel may be provided with a joint extending parallel with a rotation axis of the worm wheel, and interlocked with the elongated hole. The movable blade may be reciprocated within a predetermined range in accordance with an interlocking movement of the joint in the elongated hole.
Here, the cutter mechanism may include a stationary blade arranged so as to oppose to the movable blade through the paper path in between. The movable blade is brought into slidable contact with the stationary blade to scissor off the continuous paper.
Further, it is preferable that the cutter driving mechanism includes a detector which detects a reference position of the worm wheel.
Here, the detector may include a cam formed with the worm wheel, and a sensor, which senses an outer circumferential face of the cam.
Preferably, the printer unit further comprises a switching mechanism, which selectively transmits the driving force of the motor to either the paper feeding roller or the cutter mechanism in accordance with a rotating direction of the motor.
In such a configuration, since a transmission channel is switched in accordance with the rotating direction of the motor, a clutch mechanism using a solenoid or the like is obviated, thereby enabling a reduction in the number of parts and simplification of structure of the motor.
Here, the switching mechanism may include: a sun gear, rotated by the motor; and a pair of planetary gears, meshed with the sun gear movably around an outer periphery of the sun gear. Either one of the planetary gear may mesh with one of the paper feeding roller and the cutter mechanism in accordance with the rotating direction of the motor.
In such a configuration, the transmission channel is switched by use of the planetary gear mechanism, thereby promoting a reduction in the number of parts and simplification of structure of the printer unit.
Preferably, the print head is a thermal head, and the paper feeding roller is a platen roller opposing to the print head.
Preferably, the print head, the cutter mechanism, the motor, and the cutter driving mechanism are disposed at a casing body of a printing apparatus having a housing section which houses the continuous paper therein, and the paper feeding roller is disposed at a cover body of the printing apparatus which opens or closes the housing section.
According to the invention, there is also provided a printing apparatus comprising the above described printer unit.
The above objects and advantages of the present invention will become more apparent by describing in detail preferred exemplary embodiments thereof with reference to the accompanying drawings, wherein:
An embodiment of the invention will be described hereinbelow by reference to the accompanying drawings. As will be known from
Disposed along the paper path 16 are a thermal print head 17, a platen roller (paper feeding roller) 18 for transporting the rolled paper P at a position opposite the print head 17, and a cutter unit 19 (cutter mechanism 19a) for cutting the rolled paper P at a position downstream of the platen roller 18. When the printing apparatus 10 has received a print instruction, the print head 17 effects printing on the rolled paper P while the platen roller 18 feeds the rolled paper P. Subsequently, the printed portion of the paper is further advanced toward the discharging port 15. When the trailing end of the printed portion reaches a particular position relative to the cutter mechanism 19a, the cutter mechanism 19a cuts the paper to separate the printed portion from the paper unwound from the rolled paper P. The separated portion is then supplied from the discharging port 15 as a single cut sheet to a user.
As shown in
The printer unit 20 comprises a head unit 21 to be provided on a main body of the printing apparatus (i.e., the casing 11), a platen unit (paper feeding unit) 22 to be provided on the cover 14, a cutter unit 19 disposed above (downstream) of the head unit 21 in an overlapping manner, and a stationary blade 19b provided above the platen unit 22. As a result, in a state in which the cover 14 is opened, the platen roller 18 and the stationary blade 19b retract from the print head 17, thereby opening a paper path 16. In other words, when the rolled paper P is replaced, the cover 14 is opened, and the rolled paper P is housed in the housing section 12. Subsequently, one end of the rolled paper P is drawn to the outside of the casing 11. In this state, the cover 14 is closed, whereby the rolled paper P is set along the paper path 16.
The platen unit 22 comprises a platen frame 23 to be fixed on a lower face of the front end of the cover 14; a platen shaft 24 rotatably supported by the platen frame 23; a lock member 25 which pivots back and forth around the platen shaft 24; and springs 26 for urging the lock member 25 backward. As shown in
As shown in
Each of the springs 26 is interposed in a pulled state between a spring engagement piece 23c formed at the rear end of the platen frame 23 and the spring engagement piece 25d of the lock lever 25a. Further backward pivotal movement of the lock levers 25a, which are urged backward by the springs 26, is restricted as a result of the stopper pieces 25c coming into contact with stopper pieces 23d of the platen frame 23. At this time, the lock levers 25a are oriented in a direction substantially perpendicular to the cover 14, thereby avoiding projection of the lock levers 25a from the extremity of the cover 14. In place of the stopper pieces 23d of the platen frame 23, projections projecting outside from side plates 23a may be formed.
The head unit 21 comprises a head frame 29 to be mounted on the main body of the printing apparatus; a head support member 30 to be provided on the head frame 29 so as to be pivotable back and forth; springs 31 for urging the head support member 30 to the platen roller 18; and a drive system 32 for transmitting driving force to the platen roller 18 and the cutter mechanism 19a. The head frame 29 is formed so as to assume the shape of the letter U when viewed from the front. A step-shaped paper guide 29a (see
As shown in
An arm section 30b is provided on either side of the head support member 30 so as to extend backward. A fitting groove 30c is formed in each of the arm sections 30b such that the respective bearing members 28 fit into the grooves 30c from above when the cover 14 is closed. Further, a contact projection 30d is formed integrally on each arm section 30b so as to come into contact with a corresponding bearing member 28 and to cause the head support member 30 (print head 17) to temporarily retract from the platen roller 18. A support hole 30e is formed proximally below the fitting groove 30c on each of the arm sections 30b. The rotary shaft 33 penetrating through the support holes 30e is offset backward with reference to a printing face of the print head 17 (i.e., close to a pivot 14a of the cover 14). Both ends of the rotary shaft 33 also serve as locking shafts which engage the engagement hooks 25b of the lock levers 25a.
The springs 31 are interposed in a compressed state between the pair of spring support pieces 29d standing on the head frame 29 and the head support member 30 to be urged backward. As a result of stopper pieces 30f projecting from both ends of the head support member 30 coming into contact with the stopper pieces 29e of the head frame 29, further backward pivotal movement of the head support member 30 is restricted.
As shown in
As shown in
As shown in
The cutter driving mechanism 35 comprises the input shaft 38 arranged parallel to the platen roller 18 and the motor shaft 34a; a worm 45 provided integrally with the input shaft 38, and a worm wheel 46 meshing with the worm 45. As mentioned above, the cutter driving mechanism 35 is disposed in the back space S behind the print head 17. The input shaft 38 is rotatably supported between the front end of the left side plate 29b of the head frame 29 and a raised piece 29f provided upright at an intermediate position along the front end of the head frame 29. The worm wheel 46 is rotatably supported by the head frame 29 by way of a vertically-oriented wheel shaft 47. A joint pin 48 is projectingly provided at an eccentric position on an upper face of the worm wheel 46. The cutter driving mechanism 35 is linked to the cutter mechanism 19a by way of the joint pin 48.
As shown in
The cutter unit 19 comprises a thin cutter frame 52 and a movable blade 53 which is provided on the cutter frame 52 so as to be pivotable back and forth by way of a movable blade pivot 54. A circular opening 52a matching the locus of movement of the joint pin 48 is formed in the cutter frame 52. The joint pin 48 projects into the cutter unit 19 through the opening 52a. The movable blade 53 has an elongated joint hole 53a, and the joint pin 48 is engaged with the joint hole 53a. Specifically, the movable blade 53 is constituted so as to make a round trip within a predetermined range of movement while following movement of the joint pin 48 when the worm wheel 46 has made one rotation. During the course of movement, the movable blade 53 comes into a slidable contact with the stationary blade 19 in the manner of scissors, thereby cutting the rolled paper P.
As mentioned above, according to the embodiment, since the cutter driving mechanism 35 is placed by utilization of the back space S behind the print head 17, the printer unit 20 can be slimmed although the print head 17 and the cutter mechanism 19a are placed in an overlapping manner. Further, a motor specifically designed for use with a cutter is obviated, thereby enabling an attempt to reduce the number of parts and simplification of a control circuit.
In addition, the worm 45 of the cutter driving mechanism 35 is positioned in parallel to the platen shaft 24 and the motor shaft 34a and rotates in association with activation of the motor 34. Correspondingly, the worm wheel 46 meshes with the worm 45 and activates the cutter mechanism 19a in accordance with rotation of the worm 45. In short, the cutter driving mechanism 35 is constituted by use of a worm mechanism having a large reduction ratio. Hence, there can be achieved compact construction of the cutter driving mechanism 35, as well as a reduction in the number of parts of the cutter driving mechanism 35. Further, because the worm 45 is disposed in parallel to the platen shaft 24 and the motor shaft 34a, the drive power of the motor can be supplied to the platen roller 18 and the cutter driving mechanism 35 through use of a simple gear mechanism.
Further, by providing the gear train 36 for selectively transmitting the drive power of the motor 34 to the platen roller 18 or the cutter mechanism 19a in accordance with the direction of rotation, a clutch mechanism using a solenoid is unnecessary, and the number of parts can be reduced and the structure can be simplified.
As mentioned above, the gear train 36 comprises the sun gear 40 which rotates in accordance with activation of the motor 34; and the planetary gears 41, 42 which mesh with the sun gear 40, are movable along an outer periphery of the sun gear 40, and selectively mesh with the paper feeding transmission gear 37 or the cutter driving transmission gear 39 in accordance with the direction of rotation of the sun gear 40. Specifically, a transmission channel is switched by use of a planetary gear mechanism, thereby promoting a reduction in the number of parts and simplification of structure.
Although the embodiment of the invention has been described by reference to the drawings, the invention is not limited to the items described in connection with the embodiment and encompasses a range in which a person skilled in the art can modify the invention or realize an application of the invention on the basis of the scope of the invention, the detailed description of the invention, and the related art.
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P2001-352184 | Nov 2001 | JP | national |
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20030103793 A1 | Jun 2003 | US |