JP2001010130A - Platen holding structure and printer having that structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a platen from generating friction on a thermal head during self-adjustment by forming a self-adjustment protrusion having substantially arcuate cross-section on the back face of the platen while extending in the longitudinal direction and making a groove for holding the self-adjustment protrusion such that it can oscillate freely in a platen holding member. SOLUTION: A printer body has a bottom plate 23 extending in the horizontal direction provided with a holder 26 for holding a platen 25 such that it can oscillate freely. The holder 26 holds a planar platen 25 having an upward plane coming into press contact with a thermal head 28. The platen 25 has a planar platen base 25b attached, to the front face thereof, with a platen rubber 25a through adhesive 25c, e.g. a both sided adhesive tape, and a plastic self-adjustment protrusion having substantially arcuate cross-section and protruding along the longitudinal direction of the platen 25 is formed on the back face side of the platen base 25b. A groove 30 for holding the self-adjustment protrusion 29 is made in the holder 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a platen holding structure and a printer having this structure, and more particularly, to enabling smooth self-adjustment to pressure contact of a thermal head and enabling higher quality recording. The present invention relates to a platen holding structure and a printer having this structure.

[0002]

2. Description of the Related Art FIGS. 4 to 6 show a conventional general printer. A plate-like platen 2 is provided substantially at the center of a frame 1 of the printer so that its recording surface is substantially vertical. As shown in FIG. 4, a platen mount 3 is provided on the rear side of the platen 2.

Here, the above-described platen holding structure will be described in more detail with reference to FIG. 5. A conventional platen 2 is provided with a platen rubber 2a on the surface of a platen base 2b.
Are adhered by a double-sided adhesive tape 2c.

On the back surface of the platen 2, there is provided a self-adjusting projection 4 having a substantially triangular cross section so that a central portion protrudes along the longitudinal direction of the platen 2. The self-adjusting projection 4 is swingable about the top as a fulcrum. Further, platen locking claws 2d are formed vertically at a plurality of positions on the back surface of the platen base 2b in a direction orthogonal to the direction in which the platen 2 extends, and the platen locking claws 2d are mounted on the platen of the printer. It is inserted into the mounting hole 3a of the base 3 and is locked so as to freely and swingably fit on the platen mounting base 3 by the action of the self-adjusting projection 4.

Returning to FIG. 4, a carriage shaft 5 is provided below the front side of the platen 2 of the frame 1.
And are arranged in parallel. A flange-like guide portion 6 is formed on the front edge of the frame 1. A carriage 7 is attached to the carriage shaft 5 and the guide portion 6 so as to be reciprocally movable along the carriage shaft 5 and the guide portion 6. Have been. A thermal head 8 having a plurality of heating elements (not shown) is attached to the leading end of the carriage 7 so as to face the platen 2, and an ink ribbon is stored on the upper surface of the carriage 7. A ribbon cassette (not shown) for guiding the ink ribbon between the thermal head 8 and the platen 2 is mounted.

A paper insertion slot 10 for feeding paper (not shown) forward of the platen 2 is formed behind the platen 2, and a stepping motor (not shown) is provided at the paper insertion slot 10. A paper feed roller 11 that conveys the paper at a predetermined speed by rotating the paper feed roller 11;
A pressure roller 12 is provided for pressing the paper inserted from the paper insertion port 10 between the paper feed roller 11 and the pressure roller 12 to be conveyed.

In the above-mentioned conventional printer, a sheet (not shown) is inserted from a sheet insertion slot 10, the sheet is sandwiched between a sheet feed roller 11 and a pressure roller 12, and the sheet feed roller is driven by the stepping motor. The paper is conveyed at a predetermined speed in a direction perpendicular to the moving direction of the carriage 7 by rotating the rotation of the carriage 11. On the other hand, while the carriage 7 is being driven, the thermal head 8 is pressed against the platen 2 and the heating element is heated based on a desired recording signal to perform desired recording on the paper.

In the conventional platen holding structure, as shown in FIG. 6, when the thermal head 8 comes into contact with the platen rubber 2a when the thermal head 8 comes into pressure contact with the platen 2, the platen 2 The thermal head 8 and the platen 2 are finally swung by using the top of the self-adjusting projection 4 as a fulcrum of the swing by sliding the platen locking claw 2d and the inner surface of the platen mounting hole 3a. And are brought into proper surface contact.

[0009]

However, in the conventional platen holding structure, the top of the self-adjusting projection 4 swings as a swing fulcrum (P in the drawing). It is inevitable that friction occurs between the surface of the platen 2 which swings in a large arc and the thermal head 8 which attempts to abut on the platen 2 as shown in FIG. When this friction occurs, it takes time from the contact of the thermal head 8 to the platen 2 until the platen 2 self-adjusts and makes an appropriate surface contact. In other words, even if the time is short, there is a problem that the recording result is different before and after the appropriate surface contact between the thermal head 8 and the platen 2 is obtained, causing unevenness.

As a solution to such a problem, the present applicant has proposed a platen holding structure in Japanese Patent Application No. 9-144092.

In this platen holding structure, as shown in FIG. 7, a self-adjusting projection 4a having a substantially arc-shaped cross section is formed on the back surface of the platen 2 so as to extend in the longitudinal direction. A plurality of small rollers 14 that are in contact with and rotatable in accordance with the swing of the platen 2 are arranged in two rows in the longitudinal direction of the platen 2. According to such a platen holding structure, the platen 2
When the thermal head 8 abuts on the platen 2, the plurality of small rollers 14 abutting on the projection 4a for self-adjustment rotate on the rear surface of the platen 2 in accordance with the swing of the platen 2 around the surface thereof, so that the platen 2 An appropriate self-tuning operation can be performed without causing friction between the thermal head 8 and the thermal head.

However, in such a platen holding structure, a plurality of small rollers 14 must be provided to smoothly support the swinging operation of the platen 2, so that there is a problem that the number of parts increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and it is possible to prevent the occurrence of friction when performing self-tuning of a platen with respect to a thermal head and to easily achieve self-tuning with a simple configuration. An object of the present invention is to provide a platen holding structure capable of performing high-quality printing without uneven printing even in the case of high-speed printing.

[0014]

In order to achieve the above object, a feature of the platen holding structure according to the first aspect is that a self-adjusting projection having a substantially arc-shaped cross section is formed on the back surface of the platen so as to extend in the longitudinal direction thereof. In addition, a projection holding groove for swingably holding the self-adjusting projection is formed in the platen holding member, and a viscous body is interposed between the projection holding groove and the self-adjusting projection. And, by adopting such a configuration, the platen swings around its surface without using a special member, so that it is possible to perform self-adjustment with respect to the contact of the thermal head. An appropriate self-tuning operation can be performed without causing any friction between the thermal head and the thermal head.

[0015] The features of the printer according to claim 2 are as follows.
2. A printer provided with the platen holding structure according to claim 1, wherein, before starting recording by the thermal head, blank recording is performed until the press-contact surface of the thermal head presses substantially parallel to the press-contact surface of the platen. That is, a control unit for controlling the operation is provided. By adopting such a configuration, the platen is tilted in advance before the start of recording by performing blank recording, and the thermal head is reliably pressed evenly against the pressure contact surface of the platen to achieve high-quality recording. Is what you can do.

[0016]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIGS.

FIG. 1 shows an embodiment of a printer having a platen holding structure according to the present invention.
1 shows an embodiment of a platen holding structure according to the present invention.

The printer body 21 of the printer according to the present embodiment
Has a substrate 22 formed by bending both side plates 24A and 24B standing upright on both sides of a bottom plate 23 extending in the horizontal direction.

The bottom plate 23 is provided with a holding holder 26 for holding the platen 25 in a swingable manner.
The holding holder 26 holds a platen 25 in a flat plate shape having a press-contact surface 7 to which a thermal head 28 described later is pressed upwardly formed. Platen 2 of the present embodiment
5, a platen rubber 25a is adhered to the front surface of a plate-shaped platen base 25b with an adhesive 25c such as a double-sided adhesive tape, and the rear side of the platen base 25b is processed with plastics or the like, and the center portion is Platen 2
5 is formed with a self-adjusting projection 29 having a substantially arc-shaped cross section projecting in the longitudinal direction.

The holding holder 26 is provided with a projection holding groove 30 for holding the self-adjusting projection 29, and a viscous body 32 is provided between the projection holding groove 30 and the self-adjusting projection 29. Intervened. The shape of the protrusion holding groove 30 may be any shape as long as the self-adjusting protrusion 29 can swing smoothly. In order to make the self-adjusting protrusion 29 swing more smoothly, in the present embodiment, a cross section of the self-adjusting protrusion 29 is used. It is formed in a shape that conforms to a substantially arc shape. In addition, the protrusion holding groove 30 is not interposed between the holding
May be directly formed as a holding member. Further, as the viscous body 32, a substance whose viscosity is unlikely to change due to heat or the like is preferable, and silicone oil, salad oil or the like is preferable.

In the vicinity of the platen 25, transport rollers 33 for transporting a sheet (not shown) as a sheet-like recording medium onto the platen 25 are provided with the side plates 24A, 2A.
4B. The transport roller 33 is provided with a driven roller (not shown) supported on a support plate 34 fixed to the side plates 24A and 24B.
Are pressed against each other.

A transport motor (not shown) is supported inside the one side plate 24B, and the transport motor is driven by the transport roller 3 via a transmission gear mechanism 35A.
3, the sheet is conveyed by the rotation of the conveying roller 33 and the driven roller.

A pressure contact plate 36 urged upward by a spring member (not shown) is rotatably supported on the upstream side of the platen 25 in the paper transporting path which is substantially horizontal. . An inclined guide surface 38 that is inclined obliquely downward is continuously provided at an upstream end of the pressure contact plate 36 in the sheet transport system path, and a paper feed roller 39 is pressed against the inclined guide surface 38. .

The paper feed roller 39 is disposed such that both ends thereof are supported by the both side plates 24A and 24B. The paper is supplied via the paper feed roller 39 and the pressure contact plate 36 so that the paper is supplied in the direction of the platen 25.

The thermal head 28 includes a carriage 40
The carriage 40 is reciprocated along the platen 25 so that the thermal head 28 faces the platen 25. For this reason, a cylindrical bearing member (not shown) in which the moving direction of the carriage 40 is in the axial direction is fixed to the rear surface of the carriage 40. The bearing member is provided between the side plates 24A and 24B. The guide shaft 42 bridged through is inserted. Accordingly, the carriage 40 can reciprocate along the platen 25 while being guided by the guide shaft 42.

Before starting predetermined recording, the thermal head 28 is controlled to perform blank recording until the press-contact surface of the thermal head 28 presses substantially parallel to the press-contact surface of the platen 25. The part 43 is connected. By performing the blank recording in this manner, when the pressure contact surface between the thermal head 28 and the platen 25 is not uniformly contacted, a hit is made against the viscosity of the viscous body 32. When pressed uniformly in this manner, the viscosity of the viscous body 32 keeps its position.

On the other hand, a top plate 44 is bridged above the both side plates 24A and 24B in parallel with the platen 25. A rack 45a extending in the longitudinal direction of the top plate 44 faces downward. The formed rack plate 45 is fixed. The carriage 40 is provided with a traveling motor (not shown) for traveling the carriage 40 and a pinion (not shown) driven to rotate by the traveling motor. The rack plate 45 meshes with the rack 45a. Accordingly, the pinion rotates by driving the traveling motor mounted on the carriage 40, and the carriage 40 moves along the guide shaft 42 so as to sequentially shift the meshing position of the top plate 44 with the rack. Will be.

Then, the transport motor is driven to rotate the paper feed roller 39 to transport the paper until its leading end is caught between the transport roller 33 and a pressing roller (not shown). The sheet is conveyed and stopped until the predetermined position where the sheet is to be recorded is located on the platen 25 by the rotation drive of the sheet 33. The heating element of the thermal head 28 is recorded while moving the carriage 40 on which a ribbon cassette (not shown) is mounted while the thermal head 28 is in pressure contact with the platen 25 via the ink ribbon and the paper. The heat is selectively generated based on the information, and the ink of the ink ribbon of the ribbon cassette is transferred to the sheet to record one line. After that, the thermal roller 28 is separated from the platen 25, the transport roller 33 is driven, the next recording position of the sheet is to be positioned on the platen 25, and the carriage 40 is moved again. Record on top. In this manner, the recording on the paper can be performed by repeating the movement of the paper and the recording on the paper by the movement of the carriage 40 alternately.

Next, the operation of the platen holding structure of the present embodiment and the printer having the same will be described.

In the printer of this embodiment, when the transport motor is driven, the transport roller 33 rotates via the transmission gear mechanism 35A, and transports the paper between the transport roller 33 and the driven roller while nipping the paper. When the sheet is conveyed to the position of the press contact plate 36, the sheet is nipped between the press contact plate 36 and the feed roller 39, and the feed roller 39 rotated via the transmission gear mechanism 35B holds the sheet. Platen 2
5 to the press contact surface. Subsequently, the control unit 43 performs blank recording in which the thermal head 28 is pressed against the platen 25 a plurality of times without generating heat, whereby the platen 25 swings against the viscosity of the viscous body 32, and the platen 25 Is inclined to a position where the pressure contact surface of the thermal head 28 and the pressure contact surface of the thermal head 28 are substantially parallel to each other so that they are pressed with a uniform pressure contact force. After uniform contact between the thermal head 28 and the platen 25 in this way, the thermal head 28 is heated to thermally transfer the ink of the ink ribbon to the paper to perform desired recording.

On the other hand, the operation of the platen holding structure according to the present embodiment will be described in more detail. When the thermal head 28 contacts the platen rubber 25a when the thermal head 28 is pressed against the platen 25,
The platen 25 oscillates against the viscosity of the viscous body 32 with the center in the width direction of the surface against which the thermal head 28 is pressed against as a fulcrum P, and after the oscillating, the viscous body 3
Due to the viscosity of 2, the platen 25 is kept inclined. In this way, self-tuning is performed so that the thermal head 28 and the platen 25 finally come into proper surface contact. When the platen 25 swings, the self-adjusting projection 29 is formed in the projection holding groove 30 due to the presence of the viscous body 32.
The top of the self-adjusting projection 29 is swung in an arc while minimizing the friction generated between the self-adjusting projection 29.

Therefore, in the present embodiment, the thermal head 2 has a simple structure in which the viscous body 32 is interposed in the protrusion holding groove 30 to hold the platen 25.
Since the top direction of the self-adjusting projection 29 is swung in an arc shape as indicated by an arrow in the drawing, the surface of the platen 25 that is in pressure contact with the platen 8 is set as a fulcrum P of the swing. Friction can be prevented from being generated between the thermal head 28 and the thermal head 28 that is to be brought into contact with the flat surface. The smooth press-contact between the head 28 and the platen 25 is performed.

Further, according to the present embodiment, the time required for the platen 25 and the thermal head 28 to come into proper surface contact is also shortened. Can be prevented.

The present invention is not limited to the above-described embodiment, but can be variously modified as needed.

[0035]

As described above, according to the platen holding structure of the present invention according to the first aspect, the platen swings around its surface without using any special member, and the thermal head of the thermal head can be used. Self-tuning can be performed for the contact, and proper self-tuning operation can be performed without causing any friction between the platen and the thermal head.

According to the printer of the second aspect,
Before the start of recording, the platen is tilted in advance, so that the thermal head can be surely pressed against the pressure contact surface of the platen to perform high-quality recording.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an embodiment of a printer including a platen holding structure according to the present invention.

FIG. 2 is a perspective view showing an embodiment of a platen holding structure according to the present invention.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a schematic configuration diagram of a printer employing a conventional platen holding structure.

FIG. 5 is a simplified sectional view showing an example of a conventional platen holding structure.

FIG. 6 is an explanatory view showing the operation of a conventional platen holding structure.

FIG. 7 is a schematic configuration diagram of a printer employing a conventional platen holding structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Printer main body 22 Substrate 23 Bottom plate 25 Platen 25a Platen rubber 25b Platen base 25c Adhesive 26 Holding holder 28 Thermal head 29 Self-adjusting projection 30 Projection holding groove 32 Viscous body 33 Transport roller 39 Feed roller 40 Carriage 43 Controller

Claims (2)

[Claims] 1. A platen holding structure for swingably holding a platen against which a thermal head is pressed against a holding member, wherein a self-adjusting projection having a substantially arc-shaped cross section is extended in the longitudinal direction on the back surface of the platen. And forming a protrusion holding groove on the platen holding member to swingably hold the self-adjusting protrusion, and interposing a viscous body between the protrusion holding groove and the self-adjusting protrusion. Features a platen holding structure. 2. A printer provided with the platen holding structure according to claim 1, wherein a pressure contact surface of said thermal head is substantially parallel to a pressure contact surface of said platen before recording by said thermal head is started. A printer comprising: a control unit that controls a blank recording until the recording unit is pressed against the printer.