JP5164591B2 - Printer device - Google Patents

Description

  The present invention relates to a printer device that records ink by thermally transferring ink of an ink sheet onto a recording material such as recording paper based on image information.

  2. Description of the Related Art Conventionally, printer devices as computer output devices and digital video output devices can be classified into thermal transfer printer devices, ink jet printer devices, laser printer devices, wire dot printer devices, and the like according to recording methods. Among them, the thermal transfer printer device uses an ink sheet and a recording sheet to selectively drive a plurality of heating elements arranged in the main scanning direction to convey the ink sheet and the recording sheet in the sub scanning direction. Thus, recording is performed on the recording paper in the form of dot lines. In recent years, with the progress of input devices that handle images such as digital cameras, digital video cameras, and scanners on the input side, attention has been focused on thermal transfer printer devices.

  In general, a thermal transfer printer has a configuration in which recording is performed while a recording sheet is conveyed by a roller. However, a configuration in which a recording sheet is conveyed by an endless belt is also proposed, and Patent Documents 1 and 2 are examples. is there.

  As described in Patent Documents 1 and 2, there is no margin from the leading edge to the trailing edge in the recording paper conveyance direction, as described in Patent Documents 1 and 2. It is a point that can be recorded. In the conveyance of the recording paper by the roller in Patent Document 1, since the roller exists only in the downstream in the conveying direction, there is an area where recording cannot be performed at the leading edge of the recording paper (the range indicated by the cross line in FIG. 8 in Patent Document 1). , I couldn't make full-scale recording without margins. However, as described in Patent Documents 1 and 2, in the configuration in which the recording paper is conveyed by the belt, there is a belt as a conveying means on both the upstream side and the downstream side in the conveyance direction, so the leading edge of the recording paper It is possible to record from to the rear end.

  Further, in Patent Document 1, not only the recording paper is transported by the endless belt, but also the platen that has been a conventional cylindrical shape and a roller that is driven to rotate as the paper is transported using the endless belt is non-cylindrical and cannot be rotated. A configuration that replaces a fixed platen has also been proposed.

  Patent Document 2 proposes a configuration in which the endless belt and the recording paper are brought into surface contact when the recording paper is conveyed by the endless belt.

  FIGS. 6A and 6B show the conveyance of the recording paper by the surface contact of the endless belt disclosed in Patent Document 2, and the non-cylindrical fixed structure disclosed in Patent Document 1 (non-rotating structure). It is the figure which showed typically the printer apparatus which combined with the platen of.

  As shown in FIGS. 6A and 6B, the printer apparatus includes a thermal head 11, an ink ribbon 12, and an endless belt 13 (hereinafter, the endless belt is simply referred to as “belt”). . In addition, the printer device is provided inside the belt 13 and is driven to rotate by a driving source (not shown) to affect the conveying speed of the belt 13 and the belt 13 provided on the inner peripheral portion of the endless belt 13. And a driven roller 15 that is driven to rotate. The printer device also includes an auxiliary roller 16 provided outside the belt 13 and facing the driving roller 14 and the driven roller 5, and a platen 17 formed of an elastic member 17 a and a reinforcing member 17 b. Yes. As shown in FIG. 6, the platen is not a rotatable roller as in the configuration of Patent Document 2, but is a non-cylindrical fixed structure disclosed in Patent Document 1.

  The recording paper P is brought into close contact with the belt 13 by the auxiliary roller 16, and is transported from the close contact portion A on the upstream side in the transport direction of the thermal head 11 through the printing portion B where the thermal head 11 and the platen 17 are pressed against each other. It is conveyed to the contact portion C on the downstream side in the direction. Other color forming principles and full-color image forming methods based on color superposition are as described in Patent Document 1 and Patent Document 2.

  When such a non-cylindrical platen with a fixed structure is used, it is possible to easily obtain a good image without increasing the size of the printer device as compared with a platen with a cylindrical rotating structure such as a roller. There are advantages. The reason is as follows.

  In the case of a thermal transfer printer apparatus, it is important that the ink ribbon and the recording paper are uniformly pressed with an appropriate pressure by a thermal head and a platen in a printing unit. If the pressure is too high or too low, color development cannot be performed at an appropriate density, and if the pressure is not uniform, density unevenness occurs in the printed image, and the image quality is impaired. As shown in FIG. 7A, in the case of the platen 23 having a rotating structure, the circumferential surface is crushed at the press contact portion to form a flat portion called “nip”. 7A and 8A schematically show the relative dimensions of the nip length L1 parallel to the conveyance direction of the recording paper P and the radius of the platen in an exaggerated manner. As shown in FIG. 7B, the pressure distribution in the flat portion has a particularly high pressure at the center in the transport direction, and shows a tendency for the pressure to rapidly decrease as the distance from the center in the transport direction increases. Because of this tendency, recording cannot be performed under proper and uniform pressure conditions unless the thermal head and the platen are positioned with very high accuracy so as to be within the allowable pressure range in FIG. . Therefore, in order to obtain a good image quality, the thermal head and the platen are usually adjusted in relative positions at the time of manufacture.

  This is because the natural state of the elastic body constituting the platen crushed in the pressure contact state is a cylindrical shape. As shown in FIGS. 8A and 8B, in the case where the radius that forms the circumferential surface of the platen 33 is large, as the nip length L2 increases, Change is relatively gradual. Accordingly, the positional accuracy required for the relative position between the thermal head and the platen is relaxed. That is, as shown in FIG. 8B, the allowable pressure range is widened in the transport direction. Therefore, the larger the radius of curvature of the platen, the easier it is to obtain a good image. However, as shown in FIG. 8A, the overall size of the apparatus cannot be avoided as the diameter of the cylindrical portion of the platen increases.

Therefore, in the printer apparatus shown in FIGS. 6A and 6B, the platen is downsized while maintaining a relatively large radius of curvature, and the mechanical strength corresponding to the reduction in rigidity due to downsizing is reinforced by the reinforcing member. The platen configuration is adopted. In this printer apparatus, a belt is disposed between the recording paper and the platen so that the conveyance resistance is not directly generated on the recording paper, and the recording paper is conveyed by driving the belt. According to this configuration, while maintaining the miniaturization, the length of the nip parallel to the transport direction is increased, the pressure distribution changes gradually, and the relative relationship between the thermal head and the platen necessary for obtaining an appropriate image quality is achieved. Position accuracy required for the position is relaxed, and a good image can be easily obtained. This is an advantage of the platen having a non-cylindrical shape and a fixed structure shown in FIGS. 6 (a) and 6 (b).
JP-A-2005-271286 JP 2005-343020 A

  However, as described above, there are the following three problems in the configuration of the platen having a non-cylindrical shape and a fixed structure shown in FIGS.

  The first problem is that a sliding frictional force is generated between the inner peripheral surface of the belt and the contact surface of the platen due to the pressure contact force between the thermal head and the platen, so that the driving load of the driving roller for driving the belt is extremely high. It's great. This is because the frictional force is not directly generated on the recording paper, and this does not lead to a decrease in the conveyance accuracy, but there is a problem that the motor serving as the drive source is enlarged and the power consumption is increased.

  The second problem is concern about wear deterioration of the contact surface of the platen due to the sliding friction force generated between the inner peripheral surface of the belt and the contact surface of the platen due to the pressure contact force between the thermal head and the platen. It is to be done. This is a serious problem related to the reliability of the printer apparatus.

  The third problem is to apply a lubricant to the inner peripheral surface of the belt and the contact surface of the platen in order to reduce the first and second problems described above, so that the contact between the inner peripheral surface of the belt and the platen is reduced. Occurs when the frictional force with the contact surface is reduced. In such a case, the frictional force between the inner peripheral surface of the belt and the outer peripheral surface of the driving roller also decreases at the same time, and there is a problem that the belt conveyance accuracy decreases. Since the belt conveyance accuracy depends on the rotation accuracy of the drive roller, if even a slight slip occurs between the outer peripheral surface of the drive roller and the inner peripheral surface of the belt, the conveyance accuracy of the recording paper decreases. As a result, color misregistration is caused. Such a problem is particularly noticeable when a lubricant such as grease is applied, but the same problem may occur when a low friction coating is applied to the contact surface of the platen. Such a coating peels off from the platen as it wears, but adheres to the inner peripheral surface of the belt, and finally reduces the frictional force between the inner peripheral surface of the belt and the outer peripheral surface of the drive roller. It is because it causes it.

  SUMMARY OF THE INVENTION The present invention solves the problem of a printer device having a configuration in which a non-cylindrical fixed platen and a belt are combined to reduce the size of the printer device and easily obtain a good image. That is, the present invention can prevent the belt from slipping by suppressing an increase in driving load and wear of the platen while maintaining the advantages of the combination of the non-cylindrical and fixed structure platen and the belt. An object is to provide a printer device.

In order to achieve the above-described object, a printer device according to the present invention includes a thermal head in which a plurality of heating elements are linearly arranged to form a heating part that heats ink,
A platen provided at a position facing the heat generating portion of the thermal head;
The ink sheet ink is applied, a sheet supplying means for supplying between the service Maruheddo and the platen,
Platen is disposed on the inner peripheral side, a first endless belt for conveying the recording material with the ink sheet passes between the support Maruheddo and the platen,
A driving roller that is in contact with the inner peripheral surface of the first endless belt and drives the first endless belt;
A driven roller which the inner peripheral side of the first endless belt and supporting, constituting the path of the first endless belt,
An inner peripheral portion of the first endless belt is disposed so as to cover an outer peripheral portion of the platen, and an outer peripheral surface is provided in contact with an inner peripheral surface of the first endless belt and an inner peripheral surface is provided in contact with the platen. A second endless belt . The thermal head and the platen sandwich the ink sheet, the first endless belt, and the second endless belt.

  According to the present invention, a combination of conveyance using an endless belt that realizes full-space recording without a blank and a platen having a non-cylindrical fixed structure that can easily obtain a good image without increasing the size of the apparatus. The problem in can be greatly reduced.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a side view schematically showing the thermal transfer printer apparatus of the first embodiment. As shown in FIG. 1, the printer apparatus according to the present embodiment is opposed to a thermal head 1 in which a plurality of heating elements are linearly arranged to form a heating part for heating ink, and a heating part of the thermal head 1. And a platen 7 provided at the position. Further, the printer device includes a sheet supply unit that supplies an ink ribbon 2 as an ink sheet to which ink is applied between the thermal head 1 and the platen 7 that are pressed against each other.

  The printer device also passes through an endless belt 3 (hereinafter referred to as a loop belt) for conveying a recording paper P as a recording material together with an ink ribbon 2 through a thermal head 1 and a platen 7 that are pressed against each other. Simply referred to as belt 3). The belt 3 has a laminated structure including a heat-resistant resin layer formed on the inner peripheral side and an elastic layer formed on the outer peripheral side. A platen 7 is fixedly disposed on the inner periphery of the belt 3. Further, the belt 3 has a width dimension orthogonal to the conveyance direction of the recording paper P larger than the length in the arrangement direction of the heating elements of the thermal head 1.

  Further, the printer apparatus includes a driving roller 4 that drives the belt 3 and a plurality of driven rollers 5 that support the inner peripheral side of the belt 3 and configure the path of the belt 3. The belt 3 is provided such that the inner peripheral surface thereof is in contact with the platen 7 and the driven roller 5 and the driving roller 4 is in contact with the outer peripheral surface. The drive roller 4 is provided on the outer peripheral portion of the belt 3 and is rotationally driven by a drive source (not shown) to affect the conveyance speed of the belt 3. The driven roller 5 is provided on the inner peripheral portion of the belt 3, and is driven and rotated by the belt 3 driven by the driving roller 4. Further, auxiliary rollers 6 are provided on the outer peripheral portion of the belt 3 at positions facing the driven roller 5.

  The platen 7 provided in the printer device is integrally configured to include an elastic member 7a made of an elastic body that comes into contact with the inner peripheral surface of the belt 3 and a reinforcing member 7b made of a rigid body that supports the elastic member 7a. ing. As shown in FIG. 1, the platen 7 in the present embodiment is not a rotatable roller as in Patent Document 2, but a platen having a non-cylindrical fixed structure disclosed in Patent Document 1.

  The recording paper P is brought into close contact with the belt 3 by the auxiliary roller 6, and passes through the print portion B pressed by the thermal head 1 and the platen 7 from the upstream contact portion A in the transport direction of the thermal head 1, and then to the thermal head 1. It is conveyed toward the contact portion C on the downstream side in the conveying direction. In the print unit B, the thermal head 1 and the platen 7 are pressed against each other with the ink ribbon 2, the recording paper P, and the belt 3 interposed therebetween. In the printing unit B, recording is performed by heating and transferring the ink of the ink ribbon 2 to the recording paper P conveyed between the ink ribbon 2 and the belt 3 by the heat generating unit of the thermal head 1. In addition, the color forming principle by the thermal head 1 and the full color image forming method by color superposition are as described in Patent Documents 1 and 2.

  In the present embodiment, as a layer for reducing the frictional force on the inner peripheral surface of the belt 3 and the contact surface of the platen 7, a lubricant is applied or a low friction coating is applied. Low friction is achieved. As a result, the sliding friction between the inner peripheral surface of the belt 3 and the contact surface of the platen 7 is greatly reduced as compared with the unlubricated state of the conventional example.

  Furthermore, in the present embodiment, the driven roller 5 that supports the belt 3 forms a concave portion in which a part of the loop formed by the belt 3 is bent into a concave shape from the outer peripheral side of the belt 3. A feature of the present embodiment is that the driving roller 4 is disposed in the recess and on the outer peripheral side of the loop formed by the belt 3, and the driving roller 4 is in contact with the outer peripheral surface of the belt 3. is there.

  As shown in FIG. 1, this configuration is adopted to ensure a sufficiently large winding angle θ of the belt 3 with respect to the outer peripheral surface of the drive roller 4. By making the winding angle θ of the belt 3 sufficiently large, an important effect of increasing the conveying force of the driving roller 4 by the Euler principle can be obtained.

  As a result, the driving roller 4 can accurately convey the belt 3 without being affected by the low friction provided on the inner peripheral surface of the belt 3 and without causing a slip. Therefore, the driving roller 4 in the present embodiment has significantly higher conveyance accuracy than the state where the driving roller 4 is easily affected by the lower friction of the belt like the driving roller disposed on the inner peripheral portion of the belt as in the conventional example. Has been improved.

  Further, in the present embodiment, although not particularly illustrated, it is necessary to apply an appropriate tension to the belt in order to accurately convey the belt, and at least one of the plurality of driven rollers is provided with a biasing means having a spring or the like. The belt is biased in the direction in which tension is applied. Although not particularly shown in the present embodiment, pressure contact means having a spring or the like for pressing the thermal head and the platen in a state where the ink ribbon and the recording paper are sandwiched between the thermal head and the platen is provided. The configuration is the same as the conventional example.

  According to the present embodiment, the driving roller 4 is brought into contact with the outer peripheral surface of the belt 3 to drive the belt 3, so that high friction is required instead of the inner peripheral surface of the belt 3 that requires low friction. It can be driven by contacting the outer peripheral surface of the belt 3. Therefore, according to the present embodiment, the conveyance using a belt that realizes full-surface recording with no margins, and the non-cylindrical fixed platen that can easily obtain a good image without increasing the size of the printer device. Problems in the combined configuration can be greatly reduced.

  The configuration adopted in the present embodiment to reduce the frictional force between the inner peripheral surface of the belt 3 and the contact surface of the platen 7, that is, to reduce the friction is not particularly limited. For example, a powder lubricant may be applied or a low friction material may be coated.

  In the present embodiment, the belt composition is not particularly limited, but the inner peripheral surface of the belt 3 may be coated with a low friction material, and the contact surface of the platen 7 is coated with a high friction material. It may be a single layer structure or a multilayer structure.

(Second Embodiment)
FIG. 2 is a side view schematically showing the thermal transfer printer apparatus of the second embodiment. The difference from the configuration shown in FIG. 1 is that the contact surface of the elastic member 7a constituting the platen 7 is formed substantially flat.

  According to the present embodiment, the driving roller 4 that conveys the belt 3 is disposed on the outer peripheral side of the belt 3, so that the friction between the inner peripheral surface of the belt 3 and the contact surface of the platen 7 is sufficient by using a lubricant or the like. Can be reduced. Therefore, even when the inner peripheral surface of the belt 3 and the contact surface of the platen 7 are in surface contact with each other in a relatively wide area, the belt 3 can be conveyed with a low load. Even when the position accuracy required for positioning the relative position between the thermal head 1 and the platen 7 is maximally relaxed by making the platen 7 substantially flat with a very large radius of curvature, A good image can be obtained.

(Third embodiment)
FIG. 3 is a diagram schematically illustrating a thermal transfer printer apparatus according to the third embodiment. 3A is a plan view, and FIG. 3B is a side view. In FIG. 3A, the thermal head, the ink ribbon, and the auxiliary roller are not shown.

  As shown in FIG. 3, the printer apparatus according to the present embodiment is opposed to the thermal head 1 in which a plurality of heating elements are arranged in a straight line to form a heating unit that heats ink, and the heating unit of the thermal head 1. And a platen 7 provided at the position. Further, the printer device includes a sheet supply unit that supplies an ink ribbon 2 as an ink sheet to which ink is applied between the thermal head 1 and the platen 7 that are pressed against each other. In the thermal head 1, the heating elements are arranged along a direction orthogonal to the conveyance direction of the recording paper P, and the length of the heating elements in the arrangement direction is used and conveyed in the printer apparatus of the embodiment. It is larger than the width dimension of the maximum size recording paper P.

  The printer device also includes a first endless belt 3 (hereinafter simply referred to as a first belt) that is a loop belt for conveying the recording paper P together with the ink ribbon 2 through the thermal head 1 and the platen 7 that are pressed against each other. 1 belt 3). The 1st belt 3 is comprised by the laminated structure which has the resin layer which has the heat resistance formed in the inner peripheral side, and the elastic layer formed in the outer peripheral side. A platen 7 is fixedly disposed on the inner peripheral portion of the first belt 3. The width of the first belt 3 perpendicular to the conveyance direction of the recording paper P is larger than the length of the thermal head 1 in the arrangement direction of the heating elements.

  Further, the printer apparatus supports the inner peripheral side of the first belt 3 by supporting the driving roller 4 that is in contact with the inner peripheral surface of the first belt 3 and drives the first belt 3. And a plurality of driven rollers 5 constituting a path.

  The driving roller 4 is provided on the inner peripheral portion of the first belt 3 and is rotationally driven by a driving source (not shown) to affect the conveying speed of the belt 3. The driven roller 5 is provided on the inner peripheral portion of the belt 3 and is rotated by being driven by the first belt 3 driven by the driving roller 4. Further, auxiliary rollers 6 are provided on the outer peripheral portion of the first belt 3 at positions facing the driven roller 5.

  The printer device includes a second endless belt 8 (hereinafter simply referred to as a second belt 8) disposed on the inner periphery of the first belt 3 so as to cover the outer periphery of the platen 7. The second belt 8 is provided such that the outer peripheral surface is in contact with the inner peripheral surface of the first belt 3 and the inner peripheral surface is in contact with the platen 7.

  The platen 7 provided in the printer device is integrally configured to include an elastic member 7a that is in contact with the inner peripheral surface of the second belt 8 and a reinforcing member 7b that is a rigid body that supports the elastic member 7a. Yes. Further, the elastic member 7a has a width dimension orthogonal to the conveyance direction of the recording paper P larger than the width dimension of the maximum size recording paper conveyed and used in the printer apparatus of the present embodiment. As shown in FIG. 3, the platen in this embodiment is not a rotatable roller as disclosed in Patent Document 2, but a non-cylindrical shape disclosed in Patent Document 1 and a fixed structure (non-rotating structure). The platen.

  The recording paper P is brought into close contact with the outer peripheral surface of the first belt 3 by the auxiliary roller 6, and the printing portion B pressed against the thermal head 1 by the platen 7 from the upstream contact portion A in the transport direction of the thermal head 1. It is conveyed to. Subsequently, the recording paper P conveyed to the printing unit B is conveyed from the printing unit B toward the contact portion C on the downstream side in the conveying direction of the thermal head 1. In the printing unit B, the thermal head 1 and the platen 7 are pressed against each other with the ink ribbon 2, the recording paper P, and the first and second belts 3 and 8 interposed therebetween. In this print section B, the ink on the ink ribbon 2 is heated and transferred to the recording paper P conveyed between the ink ribbon 2 and the first belt 3 by the heat generating section of the thermal head 1 for recording. Do. In addition, the color forming principle by the thermal head 1 and the full color image forming method by color superposition are as described in Patent Documents 1 and 2.

  In this embodiment, low friction such as application of a lubricant and low friction coating is applied to the hatched area in FIG. 3B, that is, the inner peripheral surface of the second belt 8 or the contact surface of the platen 7. Measures to take are taken. As a result, the sliding friction between the inner peripheral surface of the second belt 8 and the contact surface of the platen 7 is greatly reduced as compared with the unlubricated state of the conventional example.

  In the present embodiment, the driving roller 4 is arranged on the outer peripheral side of the second belt 8 in a state where tension is applied to the first belt 3 by the driven roller 5. For this reason, even if it is a case where low friction, such as application | coating of a lubricant and low friction coating, is aimed at the internal peripheral surface of the 2nd belt 8, it is suppressed that the conveyance precision of the drive roller 4 falls. . At the same time, the inner peripheral surface of the first belt 3 is not reduced in friction by application of a lubricant, low friction coating, or the like, so that the belt can be accurately conveyed without causing slip. Therefore, according to the present embodiment, the conveyance accuracy is greatly improved as compared with the conveyance state that is easily affected by the low friction caused by the lubricant or the like provided on the inner peripheral portion of the belt as in the conventional example. .

  As described above, a relatively high frictional force is maintained on the inner peripheral surface of the first belt 3, and the conveyance accuracy of the driving roller 4 is improved. Further, the inner peripheral surface of the second belt 8 is reduced in friction, so that the sliding resistance between the second belt 8 and the platen 7 having a fixed structure is reduced, and the second belt 8 is conveyed. The load is reduced. For this reason, in this embodiment, it becomes possible to achieve both the conveyance accuracy of the driving roller 4 and the reduction of the conveyance load of the second belt 8. That is, as in the present embodiment, the configuration in which two belts are doubly wound can improve the recording paper conveyance accuracy and reduce the driving load at the same time.

  Further, in the present embodiment, as shown in FIG. 3A, the second belt 8 is formed to have a larger width dimension perpendicular to the recording sheet conveyance direction than the first belt 3. This is a device for preventing a low friction agent such as grease provided on the inner peripheral portion of the second belt 8 from entering the inner peripheral portion of the first belt 3. The second belt 8 has a width dimension orthogonal to the conveyance direction of the recording paper P larger than the width dimension of the elastic member 7 a of the platen 7.

  In the present embodiment, although not particularly illustrated, in order to carry the belt with high accuracy, it is necessary to apply an appropriate tension to the belt. For this reason, at least one of the plurality of driven rollers is urged in a direction in which the belt is tensioned by urging means having a spring or the like. In addition, although not particularly illustrated in the present embodiment, the configuration including the press contact means having a spring or the like for press-contacting the thermal head and the platen is the same as the conventional example.

  In other words, according to the present embodiment, the conveyance using the belt that realizes the entire surface recording without a margin, and the non-cylindrical fixed platen that can easily obtain a good image without increasing the size of the printer device. Problems in the combined configuration can be greatly reduced.

  The configuration for reducing the friction with respect to the inner peripheral surface of the second belt 8 and the contact surface of the platen 7 employed in the present embodiment is not particularly limited, but for example, application of grease or powder lubricant And a structure such as coating with a low friction material.

  In the present embodiment, the composition of the belt is not particularly limited, but the inner peripheral surface of the second belt 8 may be coated with a low friction material, and the outer peripheral surface of the second belt 8 may be coated with a high friction material. May be coated, and may be a single layer structure or a multilayer structure.

  Further, as shown in FIG. 4, in this embodiment, a pair of guide members 9 that guide the movement of the second belt 8 are disposed in contact with the inner peripheral portion of the second belt 8. By adopting the above, the second belt 8 can be conveyed more stably.

(Fourth embodiment)
FIG. 5 is a diagram schematically illustrating a thermal transfer printer apparatus according to the fourth embodiment. 5A is a plan view, and FIG. 5B is a side view. The difference between this embodiment and the third embodiment shown in FIG. 3 is the shape of the platen. As shown in FIGS. 5A and 5B, in the platen 27, the contact surface of the elastic member 27a is formed substantially flat.

  By providing the first and second belts 3 and 8 having a double structure, the frictional force between the inner peripheral surface of the second belt 8 and the contact surface of the platen 27 is sufficiently reduced by a lubricant or the like. Even in this case, the frictional force between the outer peripheral surface of the drive roller 4 and the inner peripheral surface of the first belt 3 can be maintained relatively high. For this reason, according to this embodiment, it is possible to carry the belt with high accuracy. For this reason, even when the second belt 8 and the platen 27 are in surface contact in a relatively wide area, the second belt 8 can be conveyed with a relatively low load. Thus, by forming the contact surface of the platen 27 in a substantially flat shape with a very large radius of curvature, the positional accuracy required for positioning the relative position between the thermal head and the platen can be relaxed to the maximum. It is possible to obtain a good image.

  Also in this embodiment, as in the first embodiment, the width of the second belt 8 is larger than that of the first belt 3 in the direction perpendicular to the conveyance direction of the recording paper. This is a contrivance for preventing the low friction agent such as grease provided on the inner peripheral portion of the second belt 8 from going around and adhering to the inner peripheral portion of the first belt 3. The second belt 8 has a width dimension orthogonal to the conveyance direction of the recording paper P larger than the width dimension of the elastic member 7 a of the platen 7.

  Also in this embodiment, although not particularly shown, it is necessary to apply an appropriate tension to the belt in order to carry the belt with high accuracy. For this reason, at least one of the plurality of driven rollers is urged in a direction in which the belt is tensioned by urging means having a spring or the like. Although not particularly shown in the present embodiment, the configuration including pressure contact means having a spring or the like for pressure-contacting the thermal head and the platen is the same as the conventional example.

  Also in this embodiment, the method for reducing the friction with respect to the frictional force between the inner peripheral surface of the second belt 8 and the contact surface of the platen 27 is not particularly limited. Measures such as application of agents and coating with low friction materials are conceivable. Also in this embodiment, the composition of the belt is not particularly limited, but the inner peripheral surface of the second belt may be coated with a low friction material, and the outer peripheral surface of the second belt may be coated with a high friction material. May be coated, and may be a single layer structure or a multilayer structure.

  Similarly, in the present embodiment, by adopting a configuration in which a pair of guide members 9 are arranged in sliding contact with the inner peripheral portion of the second belt 8 as in the configuration shown in FIG. The second belt 8 can be further stably conveyed.

It is a figure which shows the printer apparatus of 1st Embodiment. It is a figure which shows the printer apparatus of 2nd Embodiment. It is a figure which shows 3rd Embodiment. It is the elements on larger scale which show the other structural example of 3rd Embodiment. It is a figure which shows 4th Embodiment. It is a figure which shows the conventional printer apparatus. It is a figure which shows the conventional printer apparatus. It is a figure which shows the conventional printer apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thermal head 2 Ink ribbon 3 Endless belt 4 Drive roller 5 Driven roller 7 Platen 7a Elastic member 7b Reinforcement member P Recording paper

Claims (15)

A thermal head in which a plurality of heating elements are linearly arranged to form a heating part for heating ink;
A platen provided at a position facing the heat generating portion of the thermal head;
The ink sheet ink is applied, a sheet supplying means for supplying between the before and SL thermal head platen,
The platen is disposed on the inner peripheral side, a first endless belt for conveying the recording material passes between with said ink sheet and said the previous SL thermal head platen,
A driving roller that is in contact with an inner peripheral surface of the first endless belt and drives the first endless belt;
A driven roller that supports an inner peripheral side of the first endless belt and constitutes a path of the first endless belt;
An inner peripheral portion of the first endless belt is disposed so as to cover an outer peripheral portion of the platen, and an outer peripheral surface is in contact with an inner peripheral surface of the first endless belt and an inner peripheral surface is in contact with the platen. A second endless belt provided , and
The thermal head and the platen are printer apparatuses that sandwich the ink sheet, the first endless belt, and the second endless belt . The said platen is made into the fixed structure which has the elastic member which consists of an elastic body contact | abutted to the internal peripheral surface of a said 2nd endless belt, and the reinforcement member which consists of a rigid body which supports this elastic member. The printer apparatus according to 1 . The platen surface to be contacted with said second endless belt is substantially flatly formed, the printer apparatus according to claim 1 or 2. Wherein the platen and the inner circumferential surface of the second endless belt lubricant is applied, a printer apparatus according to any one of claims 1 to 3. Wherein the abutment surface of the second endless belt, a layer for reducing the frictional force is provided, the printer apparatus according to any one of claims 1 to 4 in the platen. Wherein the inner peripheral surface of the second endless belt, a layer for reducing the frictional force is provided, the printer apparatus according to any one of claims 1 to 5. Wherein the outer circumferential surface of the second endless belt, a layer for increasing the frictional force is provided, the printer apparatus according to any one of claims 1 to 6. At least one of the plurality of the driven roller, wherein comprising a first biasing means for urging the endless belt in the direction applying tension, the printer apparatus according to any one of claims 1 to 7. It said ink comprising a sheet and a pressing means for pressing the state in which the recording material is sandwiched, the printer apparatus according to any one of claims 1 to 8 between the platen and the thermal head. Said first endless belt is formed on the inner peripheral side resin layer having heat resistance, elastic layer is a laminated structure comprising formed on the outer peripheral side, according to any one of claims 1 to 9 Printer device. It said second endless belt has a width dimension perpendicular to the conveying direction of the recording material, wherein greater than the width dimension of the first endless belt, the printer apparatus according to any one of claims 1 to 10. The printer apparatus according to claim 2 , wherein the second endless belt has a width dimension orthogonal to a recording material conveyance direction larger than a width dimension of the elastic member of the platen. 3. The printer device according to claim 2 , wherein the elastic member of the platen has a width dimension orthogonal to a conveyance direction of the recording material larger than a width dimension of the maximum size recording material to be conveyed. In the thermal head, the heating elements are arranged along a direction orthogonal to the conveyance direction of the recording material, and the length in the arrangement direction of the heating elements is the width dimension of the maximum size recording material to be conveyed. greater than, the printer apparatus according to any one of claims 1 to 13. Said guide member for guiding the movement of the second endless belt, the second is contact with the inner peripheral surface of the endless belt is disposed, the printer apparatus according to any one of claims 1 to 14 .

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