JP2001088376A - Printer assembly and printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a printer of an ultrathin card type. SOLUTION: A platen roller 12 for sending a thermosensitive paper 8 while pressing the paper to a thermal head 11 is supported by a supporting plate 14 via supporting rollers 13a and 13b of members having surfaces of a small friction factor. Since the platen roller 12 can be supported along a longitudinal direction by the supporting plate 14, even the platen roller of a small diameter can apply a predetermined pressure, and a thin and compact printer assembly 10 can be assembled. A printer of a thickness of approximately 5 mm can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a printer assembly (printing function assembly) for printing on thermal paper and a printer.

[0002]

2. Description of the Related Art In recent years, a wide variety of computers have been developed and used, from a portable type such as a notebook type to a portable or mobile type such as a PDA which can fit in a pocket. further,
With the spread of the Internet, the use of computers has been expanding to various fields such as information provision and communication, and the number of users has also expanded from specialists to general users. In the future, as the number of users increases, computers are considered to be used daily in ordinary households. In addition, the use of electronic settlement has been advanced, and the daily work at home has been processed by a computer.

[0003] As computers and other mobile devices increase, it is also desired that printouts be output whenever desired. Also,
In the case of using a computer for daily business such as electronic transactions, the amount printed out is small, and the use frequency of the printer is often low. Therefore, one style required for a printer in the future can be held together with a portable information processing device (portable terminal) such as a PDA or a mobile phone, or built into the information processing device.
Furthermore, it is certain that it is thin and compact so that it can be docked to a portable terminal, and that it is lightweight and low-cost. A printer that prints on thermal paper using a thermal head does not require ink or a ribbon, so that the printing mechanism can be made compact. In particular, a line thermal printer in which the thermal head is extended in the paper width direction (scanning direction or line direction) does not require a mechanism for moving the thermal head in the scanning direction, and can be very compactly assembled. It is a suitable printer.

[0004]

However, in order to realize a printer having a very small thickness, for example, about 10 mm or less, a mechanism for pressing a printing paper against a thermal head is one of the major bottlenecks. A mechanism is adopted in which the thermal paper is sandwiched between the thermal head and the platen roller, and the paper is fed while pressing the thermal paper on the thermal head by rotating the platen roller.
To realize a thin printer having a thickness of 10 mm or less, the diameter of the platen roller needs to be smaller than conventionally thought. If the diameter of the platen roller is reduced, the contact area becomes insufficient. Therefore, in order to press the printing paper against the thermal head with a predetermined force, it is necessary to press the platen roller with a stronger force. However, if the diameter of the platen roller is set to 10 mm or less, the strength is insufficient. Therefore, if the pressing force is increased, distortion is likely to occur. In particular, when the diameter is about 5 mm or less, the entire platen roller is distorted. Therefore, the printing paper cannot be pressed against the thermal head with a force required for printing only by supporting both ends. When a line thermal head is used, in particular, the pressing force of the thermal paper varies in the paper width direction, and if the pressing force is partially insufficient, the printing quality deteriorates, so that printing is practically impossible.

[0005] In order to prevent distortion of the platen roller,
There is a method in which a platen roller is divided in a longitudinal direction to expose a shaft, and a part of the shaft is supported by a bearing. However, in the case of the platen roller, it is necessary to apply a continuous and uniform pressure in the scanning direction, so that the platen roller cannot be divided in the longitudinal direction. On the other hand, the entire platen roller can be supported by a member extending in the longitudinal direction from the side opposite to the thermal head. However, the surface of the platen roller is made of a material having a high friction coefficient such as rubber in order to smoothly feed the paper. For this reason, in the state of pressurization, there is a problem that the frictional force between such a support member and the platen roller is too large and the motor power increases. Therefore, this method cannot be adopted.

[0006] It is also possible to arrange several sub-rollers in the longitudinal direction of the platen roller to prevent distortion of the platen roller. However, in this mechanism, in addition to the platen roller, it is necessary to arrange a sub-roller and a bearing for supporting the shaft thereof, and to provide a clearance between the sub-roller and the housing. Therefore, a thin printer cannot be realized.

Under such circumstances, the inventors of the present application have been keenly developing technology for realizing a card-type thermal printer having a thickness of about 5 mm or less. Then, it was possible to solve the above-mentioned problems relating to the platen roller, and to develop a technology capable of realizing a very thin printer with high print quality.

That is, according to the present invention, a line thermal type printer is required to have a thickness of about 10 mm or less.
It is an object of the present invention to provide a printing mechanism, that is, a printer assembly, which can be integrated to about mm or less. It is another object of the present invention to provide a printer having a thickness of 10 mm or less, and further, about 5 mm or less.

[0009]

Therefore, in the printer assembly of the present invention, the platen roller is supported by a thin roller (shaft) having a small coefficient of friction and the surface of the supporting roller is supported by a plate-shaped member. By doing so, distortion of the platen roller is prevented, and further pressure can be applied. That is, the printer assembly of the present invention comprises a line thermal head, a platen roller having a high friction coefficient on the surface, and a platen roller for feeding the print sheet between the line thermal head and the print sheet. Support rollers with a low coefficient of friction on the surface arranged before and after in the paper feed direction to support from the opposite side of the thermal head, and support rollers to receive the surface of these support rollers from the opposite side of the line thermal head And a pressurizing means for applying pressure between the support plate and the line thermal head. As the platen roller, it is possible to use a metal member whose surface is processed to increase the coefficient of friction, or a resin having a large coefficient of friction such as phenolic resin, but the most suitable is a rubber-based rubber having a large coefficient of friction and elasticity. To cover the surface with a material. On the other hand, as the support roller, a resin member having a low coefficient of friction, for example, a nylon-based material or a polyethylene-based material is suitable.
It is to use a rod-shaped member made of a fluorine-based resin having a friction coefficient that is a fraction of rubber or one digit or more.

A platen roller having a large friction coefficient is received by a support roller having a small friction coefficient, and further received by a support plate extending along the longitudinal direction of the support roller, so that the platen roller is continuously provided along the longitudinal direction of the platen roller. The load of the platen roller can be supported. Therefore, even if the platen roller itself does not have high rigidity, the distortion can be prevented and a high pressure can be applied. At the same time, the supporting roller having a small friction coefficient rotates with the platen roller, and the supporting roller having a small friction coefficient rotates with respect to the supporting plate. For this reason, the frictional force when driving the platen roller can be reduced. Further, since the support roller is directly received by the support plate, it is not necessary to separate the support roller from the structural member, and the line thermal head, the platen roller, and the support roller can be arranged in a very thin space. Therefore, it is possible to assemble the printer in a very thin space, and to realize a printer assembly that can smoothly perform paper feeding with low power.

Further, by providing the support roller before and after the platen roller, the position before and after the platen roller can be defined by the support roller. Further, by arranging the platen roller and the support roller in this manner, the line connecting the central axes of the platen roller and the support roller is inclined with respect to the direction in which the platen roller and the thermal head come into contact with each other. The support rollers can be arranged even thinner.

For example, a thermal head having a thickness of 2 mm for printing paper of about postcard size (A6 size),
By combining a platen roller having a diameter of 2 mm and a supporting roller having a diameter of 1 mm, a printer assembly having a thickness of about 5 mm or less can be realized. Therefore, by combining such a thin printer assembly with a paper feeding mechanism for supplying thermal paper to the printer assembly, it is extremely thin and portable, incorporated in an information processing apparatus, and furthermore, a portable terminal such as a mobile phone. And a compact printer suitable for docking and using. When the printing paper becomes large, the platen roller requires torsional strength and the like, so that a diameter of about 10 mm is required for the platen roller. However, rigidity is not required to such an extent that the platen roller itself is not distorted by pressure unlike the conventional printer. Therefore, according to the present invention, A4 size printing paper is
A printer assembly and a printer having a thickness of about several mm can be realized.

It is an object of the present invention to provide such a very thin printer assembly and printer, and it is desirable that the diameter of the platen roller be as small as possible. Therefore, as described above, it is difficult to impart rigidity to the platen roller so as not to be distorted, or to maintain the thermal head horizontal. And in this invention, since it is made to support along a longitudinal direction with a support roller, contrary to the conventional, a flexible flexible platen roller is adopted, and this and a flexible support roller are used. By combining them, the platen roller can be brought into close contact with the thermal line head. In particular, it is difficult to reinforce the thermal line head when the whole is made thin. Therefore, when a thin thermal head is used, the thermal head itself may be curved by pressure. Even in such a case, in the printer assembly of the present invention, by employing the flexible platen roller, the platen roller can be brought into close contact with the thermal head, and the printer assembly having high reliability and print quality can be obtained. Can be provided. As such a platen roller, a roller having a flexible shaft coated with rubber forming a surface is suitable, and a supporting roller is formed of the flexible shaft itself having a low coefficient of friction. Things are suitable.

In the printer assembly of the present invention,
Since the platen roller is supported substantially continuously along the longitudinal direction, pressure may be applied in any of the upper and lower directions, that is, the direction of the line thermal head, and the pressure may be applied in the direction of the support plate. . Alternatively, pressure may be applied from both sides. For example, pressure can be applied by forming the support plate with a highly rigid member and supporting the support plate with respect to a frame or the like with a highly elastic member such as a spring or rubber. Alternatively, the support plate itself can be an elastic member such as a leaf spring.

Furthermore, when pressure is applied from the side of the support plate, the degree of adhesion of the platen roller to the line thermal head can be increased by dividing the support plate along the longitudinal direction at an appropriate pitch. In particular, it is possible to provide a printer assembly and a printer capable of increasing the degree of adhesion of the platen roller by combining with a flexible platen roller and a supporting roller, and performing high-quality printing.

Further, it is also possible to provide unevenness in the longitudinal direction of the support roller on the support plate to further reduce the frictional force between the support roller and the support plate.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a printer 1 according to the present invention.
Is shown in plan view. The printer 1 of this embodiment is a portable type printer which is entirely housed in a housing 2 having a thickness of about 5 mm and a square of about A7 size (74 mm × 105 mm), and is a printer like a thin card as a whole. Inside the housing 2, a space 3 for storing an A8 size (52 mm × 74 mm) heat-sensitive cut sheet (cut sheet or fixed form paper).
Is provided from the storage space 3 to the sheet feeding mechanism 2.
0, the cut sheets 8 are supplied one by one to the printer assembly 10, and the printed sheets are output from the discharge port 4 on the opposite side.

The paper feeding mechanism 20 of the present embodiment, as shown in an enlarged view in FIG. 2, pushes up a plate 21 arranged so as to push up the vicinity of the front end of the cut sheet 8, and cooperates with the push up plate 21. The pick-up roller 22 disposed so as to sandwich the cut sheet 8, and the front end 8 a of the cut sheet 8 fed by the pick-up roller 22, and the cut sheet located at the uppermost position (the side of the pick-up roller 22) And a separation wall (separation portion) 23 for separating only the sheet and sending the separated sheet to the printer assembly 10. In addition, push-up plate 2
A spring 24 for driving the push-up plate 21 is provided between the housing 1 and the housing 2.

The printer assembly 10 for printing on the fed thermal paper 8 includes a line thermal head (hereinafter referred to as a thermal head or head) 11 extending the full width in the paper width direction W and a thermal head 11. A platen roller 12 for sandwiching the thermal paper 8 between the thermal paper 8 and pressing the thermal surface of the thermal paper 8 against the thermal head 11, two support rollers 13a and 13b for supporting the platen roller 12 from the side opposite to the thermal head 11, And a supporting plate 14 for further supporting the supporting rollers 13a and 13b. This support plate 14 is attached to the housing 2 by a spring 15 by a spring 15.
And the platen roller 1
2 is pressed toward the printing surface 11a of the thermal head 11. As a result, the thermal sheet 8 is
The printing paper 2 is pressed against the thermal head 11 with a sufficient pressure, printed, and discharged from the paper discharge port 4.

As shown in FIG. 1, the housing 2 of the printer 1 of the present embodiment further includes a motor 61 for driving the pickup roller 22 and the platen roller 12,
The power transmission mechanism 62 is housed therein, and a space 65 for a battery serving as a power supply for the motor 61 is also provided. Although not shown, the printer 1 of the present embodiment has an interface function of receiving data to be printed by communicating with a host (terminal) such as a personal computer or a PDA, and a function of controlling the motor 61 according to the data. It has all the functions necessary to operate as a printer. Therefore, desired data can be easily printed out at any time simply by carrying the printer 1 of the present example together with a portable terminal such as a PDA. Alternatively, the portable terminal can be docked with a mobile phone or stored in a device bay of a notebook personal computer to be integrated with the portable terminal or the information processing device and carried around.

The printer 1 of this embodiment employs several mechanisms so that the whole can be made thin. First, the pickup roller 22 of the paper feeding mechanism 20 includes a plurality of rotating bodies 22b having a diameter of about 2 mm in a paper width direction.
2a, a shaft 25a extends from the housing 2 between these rotating bodies 22b.
Supported by Therefore, the printing paper 8 can be reliably picked up without being distorted on the way even with a roller having a small diameter. Generally, a method of increasing the diameter to increase the strength is employed to prevent the roller from being distorted, but for that purpose, the diameter needs to be about 10 mm or more. On the other hand, like the pickup roller 22, the roller body (rotary body) is divided into a plurality of parts.
By supporting the middle of the shaft with a bearing (shaft support) in the meantime, a mechanism for supporting the shaft within the thickness of the roller can be arranged, and bending of the shaft can be prevented. Therefore, it is not necessary for the roller itself or the roller itself to have the strength to receive all the pressure, and it is possible to reduce the diameter of the roller to about 10 mm or less, further to about 5 mm or less and to prevent distortion.

However, this supporting method cannot be applied to the platen roller 12 because the roller is divided in the longitudinal direction. That is, unless the platen roller 12 presses the printing paper over the entire length of the thermal head 11, a portion that cannot be printed or a portion that results in poor printing occurs. Therefore, in the printer assembly 10 of the present embodiment, the platen roller 12 is supported by two support rollers 13a and 13b.

FIG. 3 is an exploded view of components constituting the printer assembly 10, and FIG. 4 is a schematic cross-sectional view of the printer assembly 10 in a lateral direction.
FIG. 5 shows a schematic configuration of the printer assembly 10 as viewed from the side with respect to the longitudinal direction. The two support rollers 13a and 13b are arranged before and after the platen roller 12 in the paper feeding direction X. For this reason, the platen roller 1 is positioned in the thickness direction T connecting the center 12a of the platen roller 12 and the printing surface 11a of the thermal head 11.
2 center 12a and respective support rollers 13a and 13
The line connecting the center 13c of b is inclined, so that the configuration in which the platen roller 12 and the support rollers 13a and 13b are overlapped can be accommodated with a size smaller than the sum of the respective diameters. The platen roller 12 of the present embodiment has a resin or metal shaft 12b having a diameter of 1 mm on a silicone rubber coating layer 1b.
2c is a roller having a diameter of 2 mm, while the support rollers 13a and 13b are rod-shaped rollers or shafts made of fluororesin and having a diameter of 1 mm. Therefore, when the platen roller 12 and the support rollers 13a and 13b are arranged as in this example, the whole can be arranged in a space of 3 mm or less, for example, a thickness of about 2.5 mm.

A support plate 14 for supporting the support rollers 13a and 13b from the side opposite to the thermal head 11 is
It has a U-shape open to the side of the thermal head 11, and has support rollers 13a and 13 at front and rear corners 14a and 14b.
3b is settled. For this reason, when the platen roller 12 rotates, the two support rollers 13a and 13b are accordingly moved to the corners 14a of the support plate 14.
And 14b, the center 13c of each support roller does not move back and forth. Therefore, these support rollers 13a
Roller 1 supported in the front and rear directions by 13b and 13b
2 also does not move back and forth inside the plate 14, but rotates at a predetermined position.

Further, the support plate 14 has an arm portion 14c extending in the sheet feeding direction.
c is pressed upward by the spring 15, that is, in the direction of the thermal head 11. Therefore, the support rollers 13 a and 13 b are moved toward the thermal head 11 by the support plate 14, and as a result, the platen roller 12 is pressed toward the thermal head 11. As shown in FIG. 3, the support plate 14 is separated into several parts in the longitudinal direction L of the platen roller 12, and a spring 15 is provided for each of the separated parts 14d. The platen roller 12 of this example is flexible because it is constituted by the thin resin or metal shaft and the rubber coating as described above.
Since 3b is also made of resin, it has flexibility. Therefore, the platen roller 12 is pressed against the thermal head 11 via the support rollers 13a and 13b by the support plate 14d separated into several parts. For this reason, the platen roller 12 has a shape along the thermal head 11 and is in close contact with the thermal head 11. For example, thermal head 1
Even if 1 is slightly distorted or inclined, the platen roller 12 can be deformed and pressed along its shape. Therefore, the thermal head 11
The printing paper 8 can be brought into close contact with a predetermined pressure, and high quality printing without blurring can be performed.

In the conventional printer, the platen roller has high rigidity so that no distortion occurs in order to uniformly press the printing paper against the thermal head.
For this reason, a highly rigid metal roller having a certain diameter, for example, a diameter of 10 mm or more is employed. However, in this example, the purpose is to provide a very thin printer, and the diameter of the platen roller 12 is reduced. For this reason, since the rigidity of the platen roller 12 cannot be ensured, a flexible roller is employed instead of a roller having high rigidity, contrary to a platen roller of a conventional printer. Then, the flexible platen roller 12 is replaced with the flexible support roller 13a.
The printing paper 8 can be brought into close contact with the thermal head 11 by a flexible roller by applying pressure to the thermal head 11 via a support plate 14 which is appropriately divided in the longitudinal direction of the thermal head 11 through the support plates 14 and 13b. As described above, in the printer 1 of the present embodiment, the method is completely different from the method of increasing the rigidity of the platen roller in order to uniformly press the printing paper against the thermal head. The diameter of the platen roller 12 is reduced to realize a very thin printer 1.

Further, in order to realize a thin printer, it is necessary to reduce the thickness of the thermal head 11 itself, to omit a structure for reinforcing the thermal head, or to reduce the size. In this case, there is a possibility that the strength of the thermal head 11 cannot be secured sufficiently to maintain the level.
The thermal head 11 may be curved. However, in the printer of this embodiment, the flexible platen roller 12
The platen roller 12 and the support rollers 13a and 13b follow the shape of the thermal head 11 because the support rollers 13a and 13b are employed. Therefore, even if the thermal head is slightly deformed, the printing paper can be brought into close contact with the thermal head 11 by the platen roller 12. Therefore, a highly reliable printer with high print quality can be provided even for a very thin printer.

As shown in FIGS. 4 and 5, the inside of the plate 14, that is, the support rollers 13a and 13a
The surface 14e with which 3b contacts is provided with irregularities 16 intermittent in the longitudinal direction of the roller. Therefore, the support roller 13
a and 13b reduce the area of contact with plate 14;
The frictional force between the support rollers 13a and 13b and the plate 14 is further reduced. For this reason, the load for rotating the support rollers 13a and 13b is reduced, and as a result, the load for rotating and driving the platen roller 12 is reduced, so that the power of the motor can be reduced.

In the printer assembly (printer mechanism) 10 of this embodiment, the platen roller 12 has a rubber surface and a high coefficient of friction suitable for paper feeding.
This is fixed to a fluororesin support roller 13a having a low friction coefficient.
And 13b. Therefore, since the platen roller 12 is rotatably supported by the support rollers 13a and 13b, the platen roller 12 rotates smoothly with the printing paper 8 sandwiched therebetween. On the other hand, the support rollers 13a and 13b rotate while their surfaces are in contact with the inner surface 14e of the support plate 14, but the frictional force generated is small because their surfaces have a low coefficient of friction. Therefore, the platen roller 12 can be supported by the support plate 14 via the support rollers 13a and 13b without greatly affecting the movement of the platen roller 12. By providing the unevenness 16 on the inner surface 14e of the support plate 14 as in this example, the frictional force generated on the support rollers 13a and 13b can be reduced, so that the platen roller 12 can be more smoothly.
Can be driven.

Similarly to the pickup roller 22, the support rollers 13a and 13b may be configured such that a roller portion is divided in the longitudinal direction to form an axis, which is supported by a bearing. However, in the printer assembly 10 of the present embodiment, the diameter of the support roller 13a is about 1 mm, and is actually the axis itself. Therefore, it is impossible to form a shaft by further dividing the shaft, and it is difficult to process the shaft. In addition, the diameter is 1
It is also difficult to arrange bearings in a space of about mm. In order to support the roller with the bearing, it is necessary to provide a space between the member for supporting the bearing, for example, the housing and the support roller, in which they do not come into contact with each other. Then, it is necessary that the spacing is such that the support roller does not come into contact even if it is distorted, and that the distance includes a manufacturing tolerance. Therefore, when these are totaled, 1 to 2 mm
It is difficult to arrange this in a reasonable space. On the other hand, in the printer assembly 10 of the present embodiment, since the support rollers 13a and 13b themselves have a small coefficient of friction so that their surfaces contact the support plate, the bearings and the support rollers and the support plate are used. There is no need to provide a gap with Therefore,
The support roller and the support plate can be easily arranged in a space of about 1 mm.

When the size of the printing paper is about A4 or more, the platen roller 12 requires strength for rotational driving, apart from preventing distortion.
A diameter of about 0 mm or more is required. On the other hand, the support rollers 13a and 13b only need to be able to rotate and support the platen roller 12, so that the support rollers 13a and 13b may have a diameter similar to that of the present embodiment. Therefore, in order to minimize the thickness of the printer assembly 10, it is most preferable that the support rollers 13a and 13b be supported by the support plate 14 as in the present embodiment. Of course, the shape of the support plate 14 is not limited to this example, and the support rollers 13a and 13b are positioned between the support plate 14 and the platen roller 12 so that the platen roller 12 does not contact the support plate 14. Anything can be used. For example, a groove that determines the position where the support rollers 13a and 13b rotate may be formed on the surface instead of the U-shape. In this example, the platen roller is supported by two support rollers, but three or more support rollers may be used. In order to prevent the platen roller from directly contacting the support plate, a configuration in which one support roller is disposed between them can be adopted, but it is difficult to stably hold the position of the platen roller 12. Therefore, a configuration in which two or more support rollers are arranged in front and rear as in this example is desirable.

Although the support plate 14 is divided in the longitudinal direction in this embodiment, the platen roller 12 can be pressed against the thermal head 11 with a sufficient pressure even if the support plate is continuous in the longitudinal direction. However, as described above, since the flexible platen roller and the supporting roller are employed, it is necessary to make use of the flexibility of these members so that the platen roller 12 can be further closely contacted with the thermal head 11. It is desirable to divide the support plate and apply longitudinally dispersed pressure.

Further, in this embodiment, the support plates 14 are divided and the coil springs 15 are provided correspondingly to each of them to apply pressure. However, other types of springs such as a leaf spring and a helical spring are used. Alternatively, another elastic member such as rubber may be used instead of the spring. Further, the support plate 14 may have a structure having a function as a leaf spring. Further, in this example, a spring is provided on the support plate 14 to press the platen roller 12 in the direction of the thermal head 11, but conversely, a spring or a rubber plate is arranged on the side of the thermal head 11 to obtain the pressure. You may do it. However, it is desirable to apply pressure from the side of the support plate 14 as in the present embodiment, in that the flexibility of the platen roller 12 and the support rollers 13a and 13b is used to make close contact with the thermal head.

As described above, the printer assembly 10 of this embodiment is
Is a thermal type that does not require a space for storing consumables such as ink and employs a configuration in which the platen roller 12 is supported by the support roller 13 and the support plate 14, so that the whole can be configured to be extremely thin and compact. For this reason, by employing the printer assembly 10, it is possible to realize a very thin printer having a thickness of about a CD case or a floppy (registered trademark) disk case. And the platen roller 1
By rotating the drive 2, the printing paper 8 can be smoothly supplied, printed and discharged, and requires no special mechanism for feeding or discharging. A low-cost printer can be provided.

Although the printer is thin and compact, a sufficient pressure is applied between the platen roller and the thermal head, and the printing paper can be pressed almost evenly along the paper width direction. It is possible to provide a very thin printer, for example, having a thickness of about 5 mm. Therefore, the printer of this example can be easily purchased, can be stored anywhere such as a pocket, a handbag, a drawer on a desk, etc., and can be easily carried with a portable terminal such as a PDA or a mobile phone, or these portable devices. Docking to a device does not significantly change the size of the mobile device. Therefore, the printer can be easily used anytime and anywhere. In addition, since the output printed out on the cut sheet can be obtained, the output result can be easily used. As a result, even users who do not use frequently can carry it without stress,
It is a very convenient printer that can be used wherever it is needed.

In the above example, an A7 size card type printer has been described as an example, but it is a matter of course that the present invention is not limited to this size. It is possible to realize a printer of A8 size or less, and further, by adopting the printer assembly of the present invention, A5 or A5
Printers that use printing paper of four sizes or more can be made smaller and lighter. Of course, the print assembly of this example can also be applied to a printer that prints on roll paper, and by making the print portion compact, the entire printer using roll paper can also be compactly assembled.

[0037]

As described above, in the printer assembly and the printer according to the present invention, the platen roller for pressing the thermal paper together with the line thermal head is supported by the support plate made of a member having a small coefficient of friction. It is to be supported by. For this reason, consumables such as ink are unnecessary, and the space is not required, so that it is possible to realize a compact size, and it is possible to reduce the diameter of the platen roller to the limit.
Further, it is possible to provide a thin printer as a whole. Then, even in a thin printer assembly or a printer such as a card, the thermal paper can be pressed with a uniform pressure without distortion, so that a high quality printed matter can be provided. Therefore, according to the present invention, a major problem which has been a bottleneck for realizing an ultra-thin printer can be solved, and an ultra-thin printer having a thickness of about 5 mm can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a planar arrangement of a printer according to the present invention.

FIG. 2 is an enlarged sectional view showing a structure of a printer assembly of the printer shown in FIG.

FIG. 3 is an exploded perspective view showing main components of the printer assembly of the printer shown in FIG. 1 in an exploded manner.

FIG. 4 is an enlarged sectional view showing a part of the printer assembly.

FIG. 5 is an enlarged side view showing a part of the printer assembly.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Printer 2 Housing 3 Cut sheet storage space 4 Discharge port 8 Cut sheet (printing paper, thermal paper, thermal sheet) 10 Printer assembly 11 Line thermal head 12 Platen roller 13a, 13b Supporting roller 14 Support plate 15 Spring 16 Unevenness 20 Paper feed mechanism 21 Push-up plate 22 Pickup roller 23 Separation wall 24 Spring

Claims (8)

[Claims] 1. A line thermal head, a platen roller having a high surface friction coefficient for sandwiching a printing sheet between the line thermal head and feeding the printing sheet, and a platen roller of the line thermal head. Arranged before and after in the paper feed direction to support from the opposite side,
A support roller having a low coefficient of friction on its surface; a support plate extending along the support roller so as to receive the surfaces of these support rollers from the opposite side of the line thermal head; and between the support plate and the line thermal head. Pressurizing means for applying pressure. 2. The platen roller according to claim 1, wherein a flexible shaft is coated with rubber forming a surface, and the support roller is formed of a flexible shaft having a low coefficient of friction. A printer assembly, characterized in that: 3. The printer assembly according to claim 1, wherein said pressurizing means pressurizes from a side of said line thermal head. 4. The printer assembly according to claim 1, wherein the support plate is a member having high rigidity, and the pressing unit presses the support plate. 5. The printer assembly according to claim 1, wherein said support plate is a leaf spring, and also serves as said pressing means. 6. The printer assembly according to claim 4, wherein the support plate is divided in a longitudinal direction of the support roller. 7. The printer assembly according to claim 1, wherein the support plate has irregularities in a longitudinal direction of the support roller. 8. A printer comprising: the printer assembly according to claim 1; and a paper feed mechanism that supplies thermal paper to the printer assembly.