JPH0529757U - Serial impact printer - Google Patents

Abstract

(57) [Abstract] [Purpose] Not only does it produce clear print quality over all the sheets of printing paper in a multi-leaf sheet set, but it also produces less noise during printing, and it also uses a vibrating small platen To reduce the energy required for vibration. As a result, it is possible to reduce the cost of printing energy and to prevent the apparatus from becoming large. A piezoelectric element 46 is connected to a platen 20 facing the print head 12 with the print paper P sandwiched therebetween, and the platen 12 runs in the same direction as the back surface of the print paper P in synchronization with the print head 12. Arranged as possible.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a serial impact printer in which a print head runs along the surface of a print medium that is composed of a large number of sheets, and more particularly to an improvement of a platen that faces the print head with the print medium sandwiched therebetween.

[0002]

[Prior Art]

 Conventionally, it is difficult to obtain clear printing over the entire leaf, for example, when printing multiple sheets of print-receiving paper in which the next and subsequent leaves are carbon paper at the same time with a dot printer. For example, if the dot impact force of the print head is increased, the topmost sheet will be punctured by the dot wires and the paper will break. Conversely, if the impact force is weakened, the impact force will not be transmitted to the bottommost sheet and the number of sheets below However, there is a problem that the print is unclear and difficult to see.

Further, strengthening the dot impact force causes a problem that the impact sound at the time of printing becomes loud and causes noise pollution, and further the device becomes large in scale, such as the necessity of providing a platen capable of withstanding the impact force. there were.

As a countermeasure against these problems, an ultrasonic vibration oscillator or a high-frequency power source is connected to a platen which is arranged to face the print head with a print sheet sandwiched between them, as known from, for example, Japanese Patent Laid-Open No. 54-163108. In this case, a piezoelectric body is provided on the platen and a high-frequency power source is connected to this, and printing is performed while vibrating the platen at high frequencies.

According to these techniques, the vibrating force of the platen is applied in addition to the impact force of the print head, so that clear print quality can be obtained over all the leaves of the print paper of the multi-sheet set, and the print head itself Since the impact force of can be suppressed, it is possible to obtain benefits such as not causing noise pollution.

[0006]

[Problems to be solved by the device]

 However, according to such an impact printer, since it is necessary to vibrate the entire platen at a high frequency, a large amount of vibration energy is required for the vibration of the platen, resulting in a large increase in printing energy cost. Since the vibration source is required in addition to the platen, the large scale of the device cannot be eliminated.

The present invention has been made to solve the above-mentioned problems, and clear print quality is obtained over all the leaves of printing paper of a multi-leaf set, and noise during printing is small. Instead, a vibration-type small platen is used to reduce the energy required to vibrate the platen. As a result, it is possible to reduce the cost of printing energy and to prevent the apparatus from becoming large.

[0008]

[Means for Solving the Problems]

 In order to achieve this object, a serial impact printer of the present invention is a serial impact printer in which printing is performed on a surface of a print medium by a print head that runs along the surface of the print medium, with the print medium being sandwiched between the print head and the print medium. An ultrasonic vibration source is connected to a platen facing the print head, and the platen is arranged so as to run in the same direction as the back surface of the print medium in synchronization with the print head.

[0009]

[Action]

 According to the serial impact printer of the present invention having the above-described configuration, printing is performed on the surface of the print medium by the print head traveling on the surface of the print medium. At that time, ultrasonic vibration is applied to the platen. Is given. Then, while the print head exerts an impact force on the print medium surface, the platen side repeatedly applies a pressing force (exciting force) to the print medium surface. Therefore, for example, when the print medium is composed of a large number of sheets, clear print quality can be obtained from the uppermost leaf paper to the lowermost leaf paper.

Further, the platen also follows and moves in the direction in which the print head runs on the surface of the print medium. This allows the platen itself to be very small, and the platen vibrates sufficiently with a small vibration energy.

[0011]

【Example】

 An embodiment embodying the present invention will be described below with reference to the drawings. 1 is a perspective view of a serial dot printer 10 according to an embodiment of the present invention, and FIG. 2 is a sectional view thereof.

As shown in the figure, in this printer 10, a carriage 14 supporting a print head 12 is supported by shafts 16 and 18, so that the print head 12 is reciprocally arranged in the shafts 16 and 18. On the other hand, since the frame 22 supporting the platen 20 is supported by the shafts 24 and 26, the platen 20 is also reciprocally arranged in the same direction as the print head 12.

The carriage 14 that supports the print head 12 and the frame 22 that supports the platen 20 have the same diameter provided on a drive shaft 28 that extends in a direction orthogonal to the shafts 16, 18, 24, and 26, respectively. The drive rollers 30, 32 and belts 34, 36 stretched between the drive rollers 30, 32 and rollers (not shown) arranged at a distance from the drive rollers 30, 32, respectively. Further, the drive shaft 28 is connected to a motor (not shown). A flexible board 38 is connected to the print head 12, and print information is sent to the print head 12 via the board 38.

On the other hand, as shown in FIG. 2, the multi-sheet print target paper P has a pair of pinches arranged between the print head 12 and the platen 20 on the upstream side and the downstream side, respectively. It is sandwiched by rollers 40a, 40b and 42a, 42b and is fed in the direction of the arrow in the figure. At that time, the uppermost paper sheet of the print-receiving paper P is plain paper, and the following paper is carbon paper. The ink ribbon IR is interposed between the print-receiving paper P and the print head 12. The impact force of the print head 12 is applied to the surface of the print target paper P via the ink ribbon IR to print on the uppermost sheet surface of the print target paper P by the ink ribbon IR. Below the next leaf, the impact force of the print head 12 makes it possible to obtain a copy by carbon.

FIG. 3 is a detailed view of the platen 20. As shown, a plate spring 44 is interposed between the platen 20 and the frame 22, and a laminated piezoelectric element 46 is arranged on the back surface of the plate spring 44, that is, the surface opposite to the platen 20. To be done. The piezoelectric element 46 is configured to repeatedly expand and contract in the platen 20 direction in response to the applied AC voltage in the ultrasonic region.

According to the serial dot printer 10 configured as described above, however, as shown in FIG. 2 described above, the print head 12 is now loaded with the print-receiving paper P made up of a large number of sheets. When the print information is sent to the print substrate P via the flexible substrate 38, dot printing is performed on the surface P of the print target paper based on the print information.

At that time, since the drive shaft 28 rotates in synchronization with the transmission of the print information, the carriage 14 travels on the surface P of the printing target paper in accordance with the rotation, and the drive shaft 28 is provided with the platen 20. Since the frame 22 is also attached, the platen 20 moves in the same direction following the movement of the print head 12. The moving speeds are exactly the same because the drive rollers 30 and 32 have the same diameter as described above. Therefore, the print head 12 always comes to a position on the back surface of the print target paper P facing the print head 12.

Then, the piezoelectric element 46 applies ultrasonic vibration to the platen 20 through the leaf spring 44 by applying an AC voltage in the ultrasonic region. By the way, the pressing time of the print head 12 on the P-side of the printing paper is 100 μsec. On the other hand, depending on the condition setting, vibration is applied three times at a frequency vibration of 30 kHz and four times at a frequency vibration of 40 kHz.

Therefore, as the platen 20 is repeatedly vibrated while the print head 12 prints on the surface of the print target paper P, not only the impact force of the print head 12 on the print target paper P but also The vibrating force from the platen 20 side during the pressing of the surface P of the printing paper by the print head 12 is also applied, and high-definition, high-quality printing over the entire leaf is obtained.

FIG. 4 shows another embodiment of the platen shape. In this example, the front end of a leaf spring 48 arranged on the front surface of the frame 22 is bent to fasten screws 50 on both sides of the frame 22, and a piezoelectric element 46 is arranged on the back surface of the leaf spring 48. In this example, the platen as shown in FIG. 3 is not used, and the portion of the leaf spring 48 located on the front surface of the frame is directly substituted by the platen.

With such a configuration, the platen itself as shown in FIG. 3 is not necessary, and ultrasonic vibration by the piezoelectric element 46 is directly transmitted to the back surface of the print paper P via the leaf spring 48. The sensitivity of the piezoelectric element 46 to ultrasonic vibration is improved, and the printing quality is further improved.

[0022]

[Effect of the device]

 As is clear from the above description, according to the serial impact printer of the present invention, not only the impact force of the print head but also the ultrasonic vibration of the platen is applied to print on a print medium composed of multiple sheets of paper. In this case, it is possible to obtain clear copy print quality from the bottom sheet to the bottom sheet with low impact force without causing breakage of the top sheet. Also, since it has a low impact force, it can reduce noise and vibration generated. Furthermore, since the platen itself moves as the print head moves, a compact and lightweight structure is sufficient, and the energy required for its vibration is small, and the size of the device can be reduced. Therefore it is also very economical.

[Brief description of drawings]

FIG. 1 is a perspective view of a serial dot printer according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the serial dot printer shown in FIG.

FIG. 3 is a front view of an embodiment of an ultrasonic platen shown in this printer.

FIG. 4 is a front view of another embodiment of the ultrasonic platen.

[Explanation of symbols]

 10 Printer 12 Print Head 14 Carriage 20 Platen 22 Frame 28 Drive Shaft 34, 36 Belt 46 Piezoelectric Element 44, 48 Leaf Spring P Printed Paper IR Ink Ribbon

Claims (1)

[Scope of utility model registration request] 1. A serial impact printer in which printing is performed on a surface of a print medium by a print head running along the surface of the print medium, wherein ultrasonic vibration is applied to a platen facing the print head with the print medium sandwiched therebetween. A serial impact printer, characterized in that the sources are connected and the platen is arranged so as to be capable of running in the same direction as the back surface of the print medium in synchronization with the print head.