JP2951819B2 - Line thermal label printer - Google Patents

Abstract

PURPOSE:To make it possible to keep printing quality uniformly irrespective of the amount of the stiffness of paper. CONSTITUTION:A straight course 33 is formed on one straight line within the predetermined range upstream or downstream a printing position P, at which the heating elements of a thermal head 40 come into contact with a platen 38. The thermal head 4, which is formed by arranging a plurality of heating elements 39 on one line at an edge portion E, is employed. The thermal head 40 is tiltingly held by a head holding part 47 at an angle not interfering with the straight course 33. Since paper 35 is guided on the straight line in the straight course 33, no slippage of a printing pressure point, at which printing pressure is applied to the paper 35, to the printing position P occurs irrespective of the amount of the stiffness of the paper 35, resulting in applying constant printing pressure to the paper 35 having any stiffness whatever at all times, preventing non-conforming printing such as skipped print or the like from developing and keeping uniform printing quality.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line thermal label printer for performing line-type printing using a thermal head.

[0002]

2. Description of the Related Art Conventionally, a line thermal printer having a structure in which a plurality of heating elements arranged in a main scanning direction are selectively driven and a desired printing is performed on a sheet by conveying the sheet in a sub-scanning direction is known. Exist. As a conventional example of such a line thermal printer, a line thermal printer mainly used as a label printer is illustrated in FIGS.

[0003] First, a label paper 3 is provided in which a long backing paper 2 to which a plurality of labels 1 are attached is wound in a roll shape, and the label paper 3 is held on a paper supply shaft 4. A paper path 5 for guiding the label paper 3 pulled out from the paper supply shaft 4 to a predetermined path is provided, and a printing position P in the printing unit 6 is provided in the paper path 5.

The printing unit 6 includes a platen 7 that is driven by a driving unit (not shown) and rotates, and a line-type thermal printer in which a plurality of heating elements 8 are arranged on a line about 5 to 10 mm behind the edge portion E. Head 9 and ribbon supply shaft 10
And a ribbon supply device 14 that guides the ink ribbon 13 to a predetermined ribbon path 12 extending from the printer to a ribbon winding shaft 11. Here, the thermal head 9 is disposed to face the platen 7 with the paper path 5 interposed therebetween, and is held rotatably about the fulcrum 15 so that the heating element 8 is positioned so as to be able to freely contact and separate from the platen 7. Further, it is urged toward the platen 7 by an urging portion (not shown). The ribbon path 12 passes through a printing position P where the heating element 8 of the thermal head 9 contacts the platen 7 and is bent at an edge E of the thermal head 9.

[0005] Then, the paper path 5 is shifted more than the printing unit 6.
A label peeling plate 16 that bends the mount 2 at an acute angle and separates the label 1 from the mount 2 is provided on the downstream side. The mount 2 bent by the label peeling plate 16 is wound around a mount winding shaft (not shown), and the label 1 peeled from the mount 2 is issued from a label issuing port (not shown).

With such a structure, the label paper 3 in the paper path 5 is conveyed by the rotation of the platen 7, and in the course of the conveyance of the label paper 3, desired contents such as, for example, the label 1 are printed on the label 1 by the thermal head 9. Characters, bar codes, etc. are printed. That is, the heating elements 8 arranged in the main scanning direction are selectively driven, and the label paper 3 is conveyed in the sub-scanning direction, whereby the ink on the ink ribbon 13 is transferred to the label 1 and printing is performed. You. During printing, the ink ribbon 13 is wound around the ribbon winding shaft 11 in synchronization with the transport of the label paper 3, and the label paper 3 and the ink ribbon 13 pass through the print position P at the same speed.

[0007] The label paper 3 which has been conveyed to the platen 7 and has passed the printing position P, has only the backing paper 2 wound on a backing paper winding shaft (not shown). At this time, since the mount 2 is sharply bent by the label peeling plate 16, the printed label 1 is separated from the mount 2, and the peeled label 1 is issued from a label issuing port (not shown).

[0008]

As illustrated in FIG. 6, a circuit board 17 for driving the heating element 8 is attached to the thermal head 9. This circuit board 17
Is generally attached to the surface on which the heating element 8 is formed. The reason is that if the circuit board 17 is attached to a surface other than the surface on which the heating element 8 is formed, a lead electrode (not shown) connected to the heating element 8 must be bent at the corner of the thermal head 9 and guided to the circuit board 17. On the other hand, it is difficult to bend the lead electrode formed by the thin film technique. For this reason, the heating elements 8 and the lead electrodes connected to these heating elements 8 are formed on one smooth surface of the thermal head 9, and the circuit board 17 is mounted on the same surface as this, and formed on one surface of the thermal head 9. Conventionally, the connection between the lead electrode and the circuit board 17 is performed.

However, the circuit board 17 has the IC cover 1
8 and the connector 19 are required, whereas the IC cover 18 and the feet 19a of the connector 19 soldered or the like protrude from the surface on which the heating element 8 is formed.
The paper path 5 must be formed avoiding the cover 19 and the feet 19a of the connector 19. Therefore, the paper path 5
Is the printing position P so as not to interfere with the IC cover 18 and the like.
It is general that it bends a predetermined range upstream from.

However, if the paper path 5 is bent upstream of the printing position P, the thermal head 9 is lifted by a small amount due to the strength of the label paper 3 guided along the paper path 5, and the platen 7 The point at which the printing pressure is applied to the label paper 3 by the pressure contact force of the thermal head 9 (hereinafter, referred to as printing pressure point PS) is shifted from the printing position P. That is, the printing pressure point PS is shifted to the downstream side of the printing position P as the label paper 3 becomes stronger. For this reason, if the label paper 3 having a strong stiffness is used, the printing position P
However, there is a disadvantage that a sufficient printing pressure cannot be obtained, and printing defects such as faint printing are likely to occur. Here, FIG. 7A shows the position of the printing position P and the position of the printing pressure point PS when the label paper 3 with low stiffness is used, and FIG. The relationship is exemplified. Note that such a phenomenon is particularly likely to occur in the label paper 3 having a strong stiffness, but is not limited to the label paper 3 but is a phenomenon generally occurring in the paper having a strong stiffness.

For this reason, conventionally, it is generally practiced to prevent the deviation of the printing pressure point PS from the printing position P by increasing the printing pressure which is the pressing force of the thermal head 9 against the platen 7. However, in this case, the heating element 9 may be abraded early, or the platen 7 may be worn.
However, such a problem arises that an expensive high-output motor is required to increase the driving force of the motor, and this is not desirable. Conventionally, the printing position P is mechanically shifted according to the strength of the stiffness of the label paper 3 to be used, so that the printing position P and the printing pressure point PS coincide with each other. In such a case, the structure becomes complicated, and the adjustment for that purpose is also delicate and difficult, which is likewise undesirable.

[0012]

According to the present invention, there is provided a thermal head in which a plurality of heating elements are arranged on a line at an edge portion, a platen which is in contact with the heating element at a printing position, and a printing unit which passes through a printing position from a paper feeding unit. Paper path leading to the paper discharge section, a straight path that is a part of this paper path and is formed linearly upstream and downstream of a predetermined range of the printing position, and a paper path that is orthogonal to the paper path upstream of the thermal head in the paper transport direction. The heating element is mounted rotatably about a fulcrum extending in the direction in which the thermal head is held, and is tilted at an angle that does not interfere with the straight path to hold the thermal head. The heating element contacts the platen with the head holder that makes the platen contact the platen via the straight path.
Rotatably support the head holder so that it can be separated
The fulcrum and the mark when the thermal head is in the headset state
Is guided to the printing position at each of the upstream and downstream sides of the character position.
Bend at the edge of the thermal head and make a straight path
Supports the ink ribbon moving away from it and forms a ribbon path
Upstream and downstream ribbon supports,
Guides the print position when the multiple head is in the head-up state
Thermal ribbon to the ink ribbon
Upstream ribbon guide that supports the
A downstream ribbon guide was provided.

[0013]

The paper guided along the paper path is guided on a straight line without interfering with the thermal head in the straight path, and predetermined printing is performed on the paper by the thermal head in the guiding process. At this time, since the sheet is guided on a straight line in the straight path, there is no shift between the printing position and the printing pressure point based on the strength of the sheet. Therefore, the printing pressure is constant for paper having any stiffness, and printing defects such as faint printing do not occur, and the printing quality is constant. Also supports ink ribbon
Is the upstream ribbon support and the downstream
This is done by the ribbon support, and in the head-up state
The upstream ribbon guide and the downstream ribbon guide
Is done. The thermal head in the head-up state
Straight line connecting the upstream ribbon guide and the downstream ribbon guide
Because there is no interference, the upstream ribbon guide and the downstream ribbon guide
Do not interfere with the ink ribbon supported by the ink.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. This embodiment is an example of a line thermal printer mainly used as a label printer. Inside a main body case (not shown), a paper supply shaft 30 as a paper supply unit and a printing unit 31 are provided adjacent to each other.
Then, the printing unit 31 is moved from the paper supply shaft 30 to the printing unit 31.
After passing through the printing position P, the sheet is divided into two paths, namely, a straight traveling direction and a bending direction, and the bent path forms a paper path 32 leading to a mount paper winding shaft (not shown) as a sheet discharging unit. Have been. A part of the paper path 32 is formed in a straight line at a predetermined range above and below the printing position P, and forms a straight path 33. Further, the printing position P
In the vicinity of the downstream side, a label peeling plate 34 is provided which bends one of the paper paths 32 at an acute angle and divides the paper path 32 into two paths. That is, the paper path 32
The one bent by the label peeling plate 34 reaches the mount winding shaft, and the one not bent is the straight path 3
2 is formed so as to reach a label issuing port (not shown) as a paper discharge unit.

Here, a label paper 35 is held on the paper supply shaft 30. The label paper 35 is formed by winding a long mount paper 37 to which a plurality of labels 36 are attached in a roll shape.

The printing unit 31 includes a platen 38 driven and rotated by a driving unit (not shown), a line-type thermal head 40 in which a plurality of heating elements 39 are arranged on a line at an edge portion E, A ribbon supply device 45 that guides the ink ribbon 44 to a predetermined ribbon path 43 from the ribbon supply shaft 41 to the ribbon take-up shaft 42 is formed. Here, the thermal head 40 has the circuit board 17 including a driving circuit of the heating element 39 and a mounting portion (not shown) serving as a heat radiating member, and the mounting portion is rotatable about a fulcrum 46. Head holder 4
7 to be held. As a result, the heating element 39 faces the platen 38 with the paper path 32 interposed therebetween, and the head holding section 47 rotates about the fulcrum 46 so that the heating element 39 moves relative to the platen 38. Each part is positioned so that it can be freely contacted and separated. The thermal head 40 held by the head holding portion 47 is positioned so as to be inclined at a predetermined angle with respect to the straight path 33, and is arranged so as not to interfere with the straight path 33. An urging portion (not shown) for urging the head holding portion 47 is provided, and the head holding portion 47 is urged by the urging portion, so that the heating element 39 moves the platen at the printing position P. 38. Further, the ribbon path 43 includes the print position P.

Next, a paper path frame 48 and a ribbon path frame 49 for holding the components of the printing unit 31 and forming the paper path 32 are provided. The paper path frame 48 has a substantially rectangular shape, and the paper path frame 48
A paper width guide 50, a paper holding roller 51, and an externally wound paper guide 52 are attached at the corner closest to zero. In other words, the paper width guide 50 has a structure in which a pair of guide plates 50a opposed to each other at a position that regulates the width direction of the paper path 32 are attached to and separated from each other. The paper holding roller 51 is connected to the paper path 3.
2 and a capstan roller 53 and a pinch roller 54
And the pinch roller 54 is pressed against the capstan roller 53 by a leaf spring 55. The outer paper guide 52 has a fan shape, and the label paper 3 is an outer paper held on the paper supply shaft 30 by an arc portion thereof.
5 is guided to the paper holding roller 51. Also,
The sheet holding frame 5 is provided on the sheet path frame 48.
The platen 38 is rotatably mounted at a corner adjacent to the corner where 1 and the like are mounted, and the label peeling plate 34 is mounted. Each part is positioned such that a contact line between the capstan roller 53 and the pinch roller 54 and an outer peripheral surface of the platen 38 are in contact with a plane including an upper surface of the paper path frame 48. The path 33 has been established. In the straight path 33, a transmission type paper sensor 56 is disposed near the downstream side of the paper holding roller 51.

Next, in the ribbon path frame 49, the upstream ribbon forming the ribbon path 43 is provided at each of the upstream and downstream sides of the printing position P in the ribbon path 43 as a fulcrum of the ink ribbon 44. A support portion 57 and a downstream ribbon support portion 58 are formed. A transmission type ribbon sensor 59 is provided between the upstream ribbon support portion 57 and the printing position P in the ribbon path 43. The ribbon sensor 59 is provided with an upstream ribbon guide 60 that supports and guides the ink ribbon 44 when the thermal head 40 is raised. In the vicinity of the downstream ribbon support portion 58, a downstream ribbon guide 61 that supports and guides the ink ribbon 44 together with the downstream ribbon fulcrum 58 when the thermal head 40 is raised is formed. That is, the ink ribbon 44
Is supported by the upstream ribbon support portion 57 and the downstream ribbon support portion 58 in the headset state, and is supported by the upstream ribbon support portion 57 in the head-up state.
And the upstream ribbon guide 60, the downstream ribbon support portion 58, and the downstream ribbon guide 61, each of which is configured such that the thermal head 40 in a head-up state is connected to the upstream ribbon guide 60 and the upstream ribbon guide 60. Each part is positioned so as not to interfere with a straight line connecting the downstream ribbon guide 61.

In such a configuration, the label paper 35 in the paper path 32 is transported by the rotation of the platen 38, and in the process of transporting the label paper 35, desired contents, for example, characters, are added to the label 36 by the thermal head 40. And bar codes are printed. That is, the heating elements 39 arranged in the main scanning direction are selectively driven, and the label paper 35 is conveyed in the sub-scanning direction, so that the ink of the ink ribbon 44 is transferred to the label 36 and printing is performed. You. At the time of printing, the ink ribbon 44 is wound around the ribbon winding shaft 42 in synchronization with the transport of the label paper 35, and the label paper 35 and the ink ribbon 4
4 pass the print position P at the same speed.

The label paper 35 which has been conveyed to the platen 38 and has passed the printing position P, is wound only on a mount winding shaft (not shown). At this time, since the mount 37 is sharply bent by the label peeling plate 34, the printed label 36 is separated from the mount 37, and the peeled label 36 is issued from the label issuing port.

Here, the label paper 35 guided along the paper path 32 is guided along a straight line without interfering with the thermal head 40 on the straight path 33 from the paper holding roller 51 to the printing position P. Is printed. For this reason, the label paper 35 does not bend at the print position P, and when the label paper 35 bends, the shift of the print pressure point PS from the print position P, which tends to occur due to the strength of the paper, does not occur. Here, the printing pressure point PS is a point at which printing pressure is applied to the label paper 35. For this reason, the printing pressure is constant for the label paper 35 having any stiffness, so that printing defects such as blurred printing are prevented, and the printing quality is homogenized.

Further, it is not necessary to increase the printing pressure in order to prevent the displacement of the label paper 35 at the printing position P. For this reason, an apparatus having excellent durability in which the heating element 39 of the thermal head 40 does not cause early wear can be obtained. Further, since it is not necessary to increase the printing pressure, the platen 38 can be sufficiently driven even by a low-output driving unit, and further, there is no need to increase the structural strength of each unit, and the cost of parts can be reduced.

In this embodiment, an example of a label printer that prints on the label paper 35 has been described.
The present invention can be applied to a printer that prints on other general paper, regardless of whether it is continuous paper or cut sheet paper. In this case, the paper path is formed linearly from the paper holding roller 51 to the label issuing port through the printing position P, and the printing pressure is kept constant for the label paper 35 having any stiffness. Therefore, printing with a fixed quality can be performed even on a hard recording medium.

[0024]

According to the present invention, there are provided a thermal head having a plurality of heating elements arranged on a line at an edge portion, a platen which is in contact with the heating elements at a printing position, and a paper discharging section passing from a paper feeding section to a printing position. , A straight path that is a part of this paper path and is formed linearly upstream and downstream of a predetermined range of the printing position, and a direction that is orthogonal to the paper path on the upstream side of the thermal head in the paper transport direction. The thermal head is mounted rotatably around the fulcrum that projects and is inclined at an angle that does not interfere with the straight path. The heating element and the head holder that comes into contact with the platen via the
A fulcrum for rotatably supporting the head holding section as shown in FIG.
Upstream and downstream of the print position when the head is in the headset state
The thermal head is guided to the printing position at each side
Bent at the edge of the
Upstream ribbon supporting the ribbon and forming a ribbon path
The support part, the downstream ribbon support part, and the thermal head
Incrementally guided to the print position in the
The thermal head does not interfere with the ink ribbon
Upstream ribbon guide and downstream ribbon guide
The paper is guided on a straight line in a straight path, and printing is performed on the paper by the thermal head during the guiding process.Therefore, regardless of the strength of the paper, the printing position and the printing pressure are applied to the paper. This printing pressure point can always be matched, and therefore, the printing pressure on the paper can be kept constant irrespective of the strength of the paper stiffness. In addition, it is possible to prevent printing defects such as blurring of printing and maintain uniform printing quality . In the head-up state,
The thermal head consists of an upstream ribbon guide and a downstream
Upstream ribbon so that it does not interfere with the straight line
The guide supported by the guide and the downstream ribbon guide
Prevent the thermal head from interfering with the ribbon
Can be.

[Brief description of the drawings]

FIG. 1 is a side view showing a paper path from a paper supply unit to a label peeling plate via a printing position and a printing unit according to an embodiment of the present invention.

FIG. 2 is an enlarged side view showing a printing unit.

FIG. 3 is an enlarged side view illustrating a printing unit in a state where a thermal head is raised.

FIG. 4 is a side view showing an arrangement state of a thermal head with respect to a platen.

FIG. 5 is a side view of a printing unit and a paper path from a paper supply unit to a label peeling plate via a printing position, showing an example of the related art.

FIG. 6 is a side view showing an arrangement state of a thermal head with respect to a platen.

7A and 7B show the relationship between the strength of paper stiffness and the position of a printing pressure point with respect to a printing position. FIG. 7A shows a case where weak stiffness paper is used, and FIG. 7B shows a case where strong stiffness paper is used. FIG. 4 is a side view of a platen and a thermal head, each illustrating a case.

[Explanation of symbols]

REFERENCE SIGNS LIST 30 paper feed unit 32 paper path 33 straight path 38 platen 39 heating element 40 thermal head 46 fulcrum 47 head holding part E edge part P printing position

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-298427 (JP, A) JP-A-63-290780 (JP, A) JP-A-4-361074 (JP, A) 222783 (JP, A) JP-A-3-189168 (JP, A) JP-A-3-227661 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41J 2/32 -2 / 325 B41J 3/36 B41J 3/407 B41J 13/00 B41J 35/04 B65C 9/46 B65C 11/02

Claims (1)

(57) [Claims] 1. A thermal head in which a plurality of heating elements are arranged on a line at an edge portion, a platen in contact with the heating element at a printing position, and a paper feeding section to a paper discharging section through the printing position. A paper path, a straight path that is a part of the paper path and is formed linearly at a predetermined range above and below the printing position, and a paper path upstream of the thermal head in a direction perpendicular to the paper path. The heating element, which is rotatably mounted on a fulcrum extending and held at an angle that does not interfere with the straight path and holds the thermal head, is positioned downstream of the thermal head in the sheet conveying direction. a head holding portion for contact with said platen through said straight path, the Thermal
When the head is in the headset state,
The print position is guided to the printing position one by one on the downstream side.
Bent at the edge of the
Support the ink ribbon that separates from the path and
Upstream ribbon support and downstream ribbon support to be formed
When the thermal head is in the head-up state.
The ink ribbon guided to the printing position
Support the thermal head so that it does not interfere with the
A line thermal label printer comprising a flow ribbon guide and a downstream ribbon guide .