JPH0890870A - Printer - Google Patents

Abstract

PURPOSE: To obtain a small printer capable of printing with high precision, by improving a press mechanism to press a print head on to a platen. CONSTITUTION: A printer has a press mechanism consisting of a head press cam 50 and a head release shaft 51 that are arranged in the array direction of heating resistors of a thermal head 25, and a head press shaft 42, a head press spring 44 and a head press arm 43 that are situated right above the heating resistors of the thermal head 25 to exert the pressure from the press mechanism on the thermal head 25. a stopper 43-1 to tilt and open the thermal head 25 in the direction in which an ink ribbon magazine is mounted, and a ribbon save panel 57 that has a arc-shaped connecting part that is slidably connected to a plunger of a solenoid cylinder 56.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer in which a sheet is inserted between a print head and a platen, and the print head prints on the sheet using an ink ribbon.

[0002]

2. Description of the Related Art A printer equipped with a line thermal head for printing on paper using an ink ribbon, which is used for printing by a feed roller on which an unused ink ribbon is wound in a roll shape and a thermal head. It is known that an ink ribbon magazine (ink ribbon cartridge) including a winding roller for winding the ink ribbon is detachably provided.

In a printer in which such an ink ribbon magazine is detachably provided, it is known that the line thermal head has a cantilever structure in order to obtain good detachability of the ink ribbon magazine. By thus forming the line thermal head in a cantilever structure, the ink ribbon can be inserted from the side surface, so that the ink ribbon magazine can be set with one touch.

In addition, in a color printer for printing using a plurality of ink ribbons, there is known a printer in which a plurality of printing blocks composed of a line thermal head and a platen are arranged in series along a paper conveyance path.

In recent years, there has been a demand for downsizing of the apparatus and speeding up of processing. Even in the above-mentioned color printer, if the parts are downsized and a plurality of printing blocks are arranged in series, the distance between the printing blocks is shortened. To meet your needs.

In the conventional printer, the line thermal head pressurizing mechanism is rotated in, for example, the paper conveying direction to realize uniform pressurization to the line thermal head, and the line thermal head is moved toward the platen. A pressure mechanism for applying pressure is known. Further, in such a pressurizing mechanism, the pressurizing action point is generally not located directly above the heat-generating resistor where the line thermal head and the paper contact each other due to a design problem, and the position is displaced. .

Some line thermal heads are placed in a head-up state at the time of non-printing. Depending on the holding mechanism of the line thermal head, the position of the line thermal head is changed when the head is temporarily raised and then in the head-down state. May be deviated from the position at the time of the previous printing though it is a minute amount.

[0008]

In the conventional printer,
Since the pressure mechanism for the line thermal head is rotated in the paper transport direction, there is a problem that the distance between the print blocks cannot be made shorter than the length of the pressure mechanism.

Further, since the point of pressure applied by the pressure mechanism is not located directly above the heat-generating resistor of the line thermal head which comes into contact with the paper, there is a loss in pressure and the amount of pressure applied is lost. There was a problem that it had to be set in consideration.

Further, when the head of the line thermal head is returned from the head-up state to the head-down state, the reproducibility is poor, and there is no problem in printing with a single line thermal head, but when performing color printing with a plurality of line thermal heads. However, there is a problem that problems such as color shift may occur.

Therefore, an object of the present invention is to provide a small-sized printer capable of highly accurate printing by improving a pressurizing mechanism for pressing the print head against the platen.

[0012]

The invention according to claim 1 is
In a printer that inserts paper between a print head and a platen and prints on the paper using an ink ribbon by the print head, a pressure shaft provided in the print head and the pressure shaft are rotatable. A fitting hole member having a fitting hole for fitting and a pressurizing mechanism for applying pressure to the fitting hole member are provided.

According to a second aspect of the invention, in the first aspect of the invention, one end of the fitting hole member is rotatably supported and the other end of the fitting hole member is rotatably fitted. A fitting hole is formed, and the fitting hole member and the pressing mechanism are arranged in a direction orthogonal to the sheet conveying direction.

According to a third aspect of the present invention, in a printer which inserts a sheet between a print head and a platen and prints on the sheet using an ink ribbon by the print head, on a center line passing through the center of gravity of the print head. And a pressurizing mechanism for pressurizing the pressurizing receiving member from above the center line.

According to a fourth aspect of the invention, in the second aspect of the invention, the fitting hole member has one end rotatably rotatably supported, and the other end having a groove whose upper part is opened. When,
The elastic member is configured to urge downward from above the pressing shaft housed in the groove member, and the pressing mechanism presses the elastic member via the groove member.

According to a fifth aspect of the present invention, in a printer which inserts a sheet between a print head and a platen and prints on the sheet using an ink ribbon by the print head, the print head in contact with the platen is provided. A separation mechanism that separates the platen from the platen, a separation drive unit that is fixed to the apparatus main body and drives the separation mechanism, and a rotation mechanism that rotates the print head having the separation mechanism in a direction that separates the print head from the platen are provided. The connecting member between the separating mechanism and the separating drive means has an arc shape corresponding to the rotation of the print head by the rotating mechanism.

According to a sixth aspect of the present invention, in a printer in which a sheet is inserted between a print head and a platen, and the print head prints on the sheet using an ink ribbon, the print head is brought into contact with the platen and applied. The pressure mechanism that presses and separates from the print head to release the pressure, and the separation distance of one end of the print head on the opposite side of the ink ribbon insertion direction when releasing the pressure by this pressure mechanism And a stopper for limiting the distance to the minimum extent that does not hinder the separation of the print head on the ink ribbon insertion direction side from the other end of the print head.

[0018]

In the invention according to claim 1, since the print head is held by fitting the pressure shaft provided in the print head into the fitting hole of the fitting hole member, the print head is not displaced. It depends on the gap between the pressure shaft and the fitting hole. Also,
The pressure applied by the pressure mechanism acts on the print head via the fitting hole member and the pressure shaft.

In the invention corresponding to claim 2, claim 1
One end of the corresponding fitting hole member is rotatably supported,
Since the fitting hole into which the pressurizing shaft is rotatably fitted is formed at the other end, when the fitting hole member is pressed by the pressing mechanism, the fitting hole member rotates about one end as the center of rotation. By moving, the pressure shaft is driven through the fitting hole, and the print head is driven through the pressure shaft. Further, since the fitting hole member and the pressing mechanism are arranged in the direction orthogonal to the sheet conveying direction, the length of the fitting hole member and the pressing mechanism in the sheet conveying direction can be shortened. , The distance between the print heads can be shortened.

According to the third aspect of the invention, the pressure applied by the pressure mechanism acts on the print head from the center line passing through the center of gravity of the print head via the pressure receiving member.

In the invention corresponding to claim 4, claim 2
The fitting hole member of the corresponding invention is composed of the groove member and the elastic member, and the pressing shaft housed in the groove member is fixed to the bottom of the groove of the groove member by the urging force of the elastic member.

Further, if the pressure shaft together with the print head overcomes the urging force from above the elastic member and is lifted upward, the print head together with the pressure shaft can be removed from above the groove of the groove member. .

According to the fifth aspect of the invention, the print head is rotated by the rotating mechanism in the direction away from the platen, and the gap between the print head and the platen is expanded. At this time, since the connecting member between the separating mechanism and the separating drive means has an arc shape corresponding to the rotation of the print head by the rotating mechanism, the connecting member does not come off the separating mechanism or the separating drive means.

According to the sixth aspect of the invention, when the pressure is released by the pressure mechanism, the print head is separated from the platen. At this time, the distance between the ends of the print heads on the opposite side of the ink ribbon insertion direction is limited by the stopper to the minimum extent that does not hinder the ink ribbon insertion.
The other end of the print head is further separated from the platen, and the print head opens greatly on the ink ribbon insertion side.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a view showing a transport path 4 to which the present invention is applied.
FIG. 1 is a diagram showing a schematic configuration of a single-pass type color printer 1 provided with individual printing units in order.

Ink ribbon magazines 3 to 6 are detachably provided in series on the sheet conveying path 2 in order, and these ink ribbon magazines 3 to 6 are provided in yellow, magenta, cyan, and black colors, respectively. Ink ribbon has been set.

At the main body side portion of the color printer 1 in which the ink ribbon magazines 3 to 6 are mounted, a take-up side rotary joint 3-1 connected to the take-up side rollers provided in the ink ribbon magazines 3 to 6. ˜6-1, supply side rotary joints 3-2 to 6-2 connected to the supply side rollers, and four head blocks (only the mounting member of each head block is shown in FIG. 1) 7 to 10 are provided. ing.

Each winding side rotary joint 3-1 to 6-1
Is connected to a take-up side motor (not shown) via a gear, and each of the supply side rotary joints 3-2 to 6-2 is connected to a back tension motor (not shown) via a gear. The platens 11 to 14 are provided so as to face each of the head blocks 7 to 10.

Reinforcing plates 15-1 for connecting a main frame and a side frame, which will be described later, are provided above and below the paper supply port 15 to which paper is supplied from a paper supply mechanism (not shown).
And 15-2 are formed. Each of these reinforcing plates 15-1, 1
R-shaped paper supply guides 15-3 and 15-4 are integrally formed on the end surface of the paper supply port 15 side of 5-2.

The paper supplied from the paper supply port 15 is first of all the center guide 1 formed of a rack and pinion.
Centering is carried out via 6, and immediately after that, it is inserted between the carrying roller 17 and a pinch roller 18 arranged so as to face the carrying roller 17. By driving the transport rollers 17, the paper is transported through the transport path 2 and supplied to the ink ribbon magazines 3 to 6 (the head blocks 7 to 10).

At this time, for example, on the paper, by a gap sensor 19 composed of a transmission type optical sensor and a reflection type optical sensor provided in the conveying path 2 immediately after the conveying roller 17 and the pinch roller 18. Black marks printed at predetermined intervals are detected on the backing only portion (label front and rear edges) between the labels that are attached at predetermined intervals. By driving the conveying roller 17 and the pinch roller 18, the paper further passes through each of the ink ribbon magazines 3 to 6 in order, printing is performed based on the detection timing of the gap sensor 19, and finally printing is completed. The formed sheet is discharged from the sheet discharge port 20 to the outside of the color printer 1.

The pinch roller 18 is rotatably supported at one corner of a substantially triangular pinch roller mounting frame 18-1. The other corner of the pinch roller mounting frame 18-1 is a pinch roller frame 18-. It is pivotally supported by 2. The remaining one corner of the pinch roller mounting frame 18-1 is fixed to a pinch roller frame shaft 18-3 which rotatably supports the pinch roller frame 18-2 in the direction shown by a broken arrow R in FIG. The pinch roller pressing spring 18-4 is connected.

When the pinch roller frame 18-2 is set (at the lowest position), the other corner shaft of the pinch roller mounting frame rotatably supported by the pinch roller frame 18-2 is set. The upper end of the hook plate 21 is engaged with the hook portion. The approximate center of the hook plate 21 is rotatably supported by a side frame, which will be described later, and the lower tip end thereof is always rotated counterclockwise in FIG. 1 by the hook plate spring 21-1 in the direction in which the hook plate 21 is rotated. It is supposed to be urged to.

The pinch roller pressing spring 18-4
Always pulls the pinch roller mounting frame 18-1 in the direction of the pinch roller frame shaft 18-3, and when the pinch roller frame 18-2 is set (lowermost position)
First, the pinch roller 18 is pressed toward the conveying roller 17 via the pinch roller mounting frame 18-1.

The hook plate 21 is provided with a cam 21-2 for releasing the hook state, and a release lever 21-3 fixed to the cam 21-2 is provided. That is, when the release lever 21-3 is pushed downward (turned clockwise), the cam 21-2 turns, the hook plate 21 turns clockwise, and the hook plate 21-3 turns clockwise.
The hook portion at the upper tip of the pinch roller frame 18 is disengaged from the other corner shaft of the pinch roller mounting frame 18-2, and the pinch roller frame 18 is moved to the pinch roller pressing spring 18-4.
It moves to the upper position by the pulling force of.

The surface of the carrying roller 17 is made of a material having a high coefficient of friction such as rubber, and is higher than the coefficient of friction of the surface of each of the platens 11 to 14, and the carrying roller 17 and the pinch roller. The conveying force (holding force) of the continuous sheet by 18 is larger than the conveying force (tensile force) of the continuous sheet by each of the platens 11-14. The transport roller 17 is formed by a roller called a projection roller or a thermal spray roller.

The rotating shaft of the carrying roller 17 is connected to the rotating shaft of a first motor 22 composed of a stepping motor via a plurality of gears, and the first motor 22 controls the rotation of the carrying roller 17. It is supposed to be done.

In the magazines 3 to 6, the rotation axis of the platen 11 arranged to face the first head block 7 to be printed first, and the platen 12 arranged to face the head block 8 to be second printed. Is connected to the rotation shaft of the second motor 23 via a plurality of gears having different gear ratios, and the second motor 23 controls the rotation of the platens 11 and 12, respectively. It has become so.

The rotation axis of the platen 13 opposed to the head block 9 for third printing and the rotation axis of the platen 14 opposed to the head block 10 for fourth printing are respectively A third stepping motor comprising a gear having different gear ratios.
Is connected to the rotary shaft of the motor 24 of
The rotation of the platens 13 and 14 is controlled by 0.

The second motor 23 and the third motor
Motor 24 and a plurality of gears connected between the two motors 23 and 24 and the platens 11 to 14 adjust the number of revolutions of each motor 23 and 24 and the gear ratio of each gear. As a result, the peripheral speeds of the platens 11 to 14 are designed to be higher than the peripheral speed of the transport roller 17 and gradually increase in the order of printing.

Each head block 7-10 has a down position which moves vertically above the platens 11-14 and comes into contact with an up position spaced apart from the platens 11-14. Thermal heads 25 to 28 are provided as heads. FIG. 1
Then, the thermal heads 25 to 28 are in the down position (
It is located at the printable position).

Further, each of the thermal heads 25 is
Each of the head blocks 7 to 10 having
The fulcrum shaft 29 is rotatably provided in the vertical direction, and the fulcrum shaft 29 is fixed to the main frame of the color printer 1.

Further, in the vicinity of the paper discharge port 20, there is a substantial Y
A peeling member 30 formed in a shape is provided.

In the transport path 2, the paper guide member 31 has a tip lower than the apex of the platens 11 to 14 and a rear end thereof to the apex of the platens 11 to 14 along the paper transport direction. It is provided so as to have the same height. Further, in the approximate center of the paper guide member 31,
The steps are formed to the extent that it does not hinder the transportation of paper,
Due to this step, paper dust and paper dust (paper dust) are accumulated.

FIG. 2 is a front view showing the schematic construction of the head blocks 7 to 10, and FIG. 3 is a side view showing the outline of the head blocks 7 to 10.

The thermal heads 25-28 are composed of a substrate 25-1 (-28-1) having a heating resistor formed in a line and a radiator plate 25-2 (-28-2) made of aluminum.
), A head mounting plate 41 is provided on the upper surface of the heat radiating plate 25-2 directly above the position of the heat generating resistor at the tip (lowermost end) of the substrate 25-2. Has a fitting hole in which the head pressure shaft 42 is fitted.

The head pressurizing shaft 42 is housed in a U-shaped shaft receiving portion which is formed at the tip of the head pressing arm 43 and has an open upper portion, and the head pressing shaft 42 is always accommodated in the shaft receiving portion. A head pressure spring 44 for pressing the pressure shaft 42 toward the thermal head 25 (downward in FIGS. 2 and 3) is attached to the lower surface of the head pressure arm 43 by welding (spot welding) or the like. .

Therefore, the head pressure shaft 42 is
The head pressure spring 44 rotatably and rotatably supports a shaft receiving portion of the head pressure arm 43 by the head pressure spring 44.

The head pressing arm 43 is rotatably supported by the head frame 46 by the head pressing arm rotating shaft 45, and the head pressing arm rotating shaft 45 is also provided.
One end of the first torsion spring 47 attached to is fixed. This first torsion spring 47
The other end of the main frame 4 of the head frame 46.
It is fixed to the first head side frame 49 provided on the 8 side (the left side in FIG. 3).

Therefore, the head torsion arm 47 is always urged by the first torsion spring 47 in the direction (upward direction) in which it rotates counterclockwise about the head pressure arm rotation shaft 45. To be done.

The head frame 46 is formed into an approximately H shape by extrusion molding an aluminum material or the like.
The upper end serves as a guide when the ink ribbon magazine 3 is mounted, and a fan or the like for cooling the thermal head can be attached to the upper surface at the position shown by the broken line.

A head pressure cam 50 is in contact with the upper surface of the head pressure arm 43. The head pressure cam 50 is fixed to a head release shaft 51. The head pressing arm 43 is rotated by the rotation to rotate the head pressing arm 43.
It is pushed down in the direction of 1, or moved in a direction away from the platen 11.

On the lower surface of the head pressing arm 43, there is formed a stopper 48-1 for restricting the rising of the upper surface of the thermal head 25 on the main frame 48 side.
That is, when the head is lifted up by the head release shaft 51, the thermal head 25 is supported only by the head pressure shaft 42 so that the thermal head 25 moves up while maintaining a substantially horizontal state. Since the head pressing arm rotation shaft 45 is rotated about the rotation center, the stopper 43-1 contacts the thermal head 25, and the main frame 48 side of the thermal head 25 moves toward the platen 11, The opposite side of the main frame 48 of the thermal head 25 is further separated from the platen 11, and the thermal head 25 opens and tilts in the direction in which the ink ribbon magazine 3 is inserted.

One end of the head release shaft 51 is rotatably supported by the first head side frame 49, and the other end of the head release shaft 51 is a second end provided on the side of the head frame 46 opposite to the main frame 48. The head side frame 52 is rotatably supported by the head side frame 52, and the head release lever 53 is attached to the tip of the head side frame 52 so as to project further.

The first side frame 49 is fixed to a head block mounting member 54 rotatably supported by the fulcrum shaft 29. The head head block mounting member 54 has a second head mounted on the fulcrum shaft 29.
One end of the torsion spring 55 is fixed.
The other end of the second torsion spring 55 is fixed to the main frame 48. Although not shown, the head block mounting member 54 is provided with a damper so that the rotational speed of the head blocks 7 to 10 is limited so that smooth movement can be obtained.

Therefore, by the second torsion spring 55, the head block mounting member 54, that is, the head block 7 is always urged in the direction (upward direction) rotating counterclockwise about the fulcrum shaft 29. To be done.

The plunger 5 of the solenoid 56 fixed to the main frame 48 via a mounting member (not shown).
One end of a ribbon save plate 57 is slidably attached to 6-1 and a substantially center of the ribbon save plate 57 is rotatably provided on the head frame 46 via a ribbon save shaft 57-1. The other end is in contact with the lower portion of the head pressure shaft 42. Therefore, the plunger 5
When 6-1 is drawn into the solenoid 56, the other end of the ribbon save plate 57 rotates counterclockwise (rotates upward) to push up the head pressing shaft 42, and the thermal The head 25 is adapted to float above the platen 11.

One end of the ribbon save plate 57 attached to the plunger 56-1 is formed in an arc shape so that the head block 7 does not come off even when the head block 7 rotates about the fulcrum shaft 29. ing.

A magnet 58 is provided on the main frame 48 at a position corresponding to the lowermost position of the first head side frame 49 when the head block 7 is at the closed position (lowermost position). The head block 7 is held in the closed position by the magnet 58. Further, the first head side frame 49
Is formed with a vertically long elliptical head positioning hole 49-1 for positioning the head block 7 in the transport direction, and a head positioning pin 59 fitted into the head positioning hole 49-1 is provided on the main frame. 48.

On the other hand, one end of the platen 11 is rotatably supported by the main frame 48, and the other end of the platen 11 is open at an upper portion of the side frame 60 positioned with high precision with the main frame 48. The tip portion of the other end is housed in the groove and is rotatably supported by a platen frame 61 which is positioned in the side frame 60 with high accuracy by pins and fitting holes.

The main frame 48 and the platen frame 61 are made of the same stamped material.
Therefore, the main frame 48 and the platen frame 61 are positioned relative to each other via the side frame 60, and the platens 11 to 14 are set in parallel with each other at the same height.

Further, the heat dissipation plate 2 of the thermal head 25
Head positioning plates 25-3 and 25-4 each having a groove opened downward are attached to both side surfaces of 5-2, and the head positioning pin 62 is housed in the groove of the head positioning plate 25-3. -1 is provided on the main frame 48, and a head positioning pin 62-2 accommodated in the groove of the head positioning plate 25-4 is provided on the platen frame 61.

Further, the main frame 48 is provided with magazine positioning pins 63 for positioning the ink ribbon magazines 3 to 6. Head magazine positioning holes 64 for positioning the ink ribbon magazines 3 to 6 are formed in the second head side frame 52, and the platen frame 61 is further provided.
Is provided with a platen magazine positioning pin 65 for positioning the ink ribbon magazines 3 to 6.

FIG. 4 shows the ink ribbon magazine 3 (
6) is a front view showing a schematic structure of FIG. 6), and FIG. 5 is a side view showing a schematic structure of the ink ribbon magazine 3 (to 6).

In the ink ribbon magazine 3, a first magazine frame 71 and a second magazine frame 72 are arranged to face each other, and a plurality of reinforcing shafts 73 are provided as a connecting portion between the magazine frames 71 and 72. The magazine frames 71 and 72 are held in parallel. It should be noted that the reinforcing shaft 73 includes a part that constitutes a conveyance path for the ink ribbon, and can be easily inserted and removed as necessary. For example, when the reinforcing shaft 73-1 is selected from the reinforcing shafts 73-1 and 73-2, the transport path when the cold ink ribbon is used is formed. Further, when the reinforcing shaft 73-2 is selected, the transport path when the hot ink ribbon is used is formed.

At a substantially upper half portion between the first magazine frame 71 and the second magazine frame 72, a take-up roller 74 for taking up the ink ribbon used for printing and an unused roller 74. The supply side roller 75 around which the ink ribbon is wound is connected to the magazine frames 71, 72.
Are arranged in a vertical line along the longitudinal direction of the magazine, that is, in the vertical direction and at a predetermined interval in consideration of the maximum winding diameter of the ink ribbon. In each of the magazine frames 71 and 72, the winding side roller 74 and the supply side roller Both ends of 75 are rotatably supported.

On the other hand, each magazine frame 71, 72
A hollow portion is formed in a substantially lower half portion between the two to accommodate the head block 7 of the color printer 1 main body.

The take-up side roller 74 and the supply side roller 75 penetrating the second magazine frame 72.
The ends of the respective rotary shafts are connected to the winding side joint 3-1 and the supply side joint 3-2 of the color printer 1 main body.

The first magazine frame 71 is provided with a magazine head positioning pin 76 which fits into the head magazine positioning hole 64 formed in the second head side frame 52, and further the platen frame 61. Is formed with a platen magazine positioning hole 77 that fits into the magazine platen positioning pin 65. The second magazine frame 72 is formed with a magazine positioning hole 78 that fits with the magazine positioning pin 63 provided on the main frame 48.

The first magazine frame 71 is provided with a release lever frame 79, and the release lever frame 79 is formed with an opening 80 in conformity with the shape of the head release lever 53.

That is, when the ink ribbon magazine 3 is mounted on the main body of the color printer 1, the head release lever 53 has the opening 8 of the release lever frame 79 when the thermal head 25 is in the up position.
When 0 is passed and the head release lever 53 is rotated to bring the thermal head 25 to the down position,
The head release lever 53 is disengaged from the opening 80 and comes into contact with the head release frame 79 so that the ink ribbon magazine 3 cannot be removed.

Further, the mounting base 81 which pivotally supports the respective rotation shafts of the winding side roller 74 and the supply side roller 75 of the magazine frames 71 and 72 is a bush nut 82.
It is detachably installed.

Further, the second magazine frame 72
An R-shaped sheet guide member 83 for guiding the sheet inserted between the thermal head and the platen in the up position to the platen side is formed at the lower end of the sheet.

When the ink ribbon magazine 3 is set in the main body of the color printer 1 so as to accommodate the head block 7, the position of the second head side frame 52 of the head block 7 and the position of the platen frame 61 are set. However, since the head block 7 is determined through the ink ribbon magazine 3, the head block 7 is pseudo-supported.

The four ink ribbon magazines 3 to 6 and the head blocks 7 to 10 have the same structure. Here, as described above, one ink ribbon magazine (3) is used. And the head block (7) and other ink ribbon magazines (4-6)
) And other head blocks (8-10) are omitted.

FIG. 6 is a perspective view showing an exploded structure of the center guide 16.

The center guide 16 is a pinion 91.
A guide base 92 in which two opening grooves having a parallel difference in diameter of the pinion 91 are formed; and a rack 93 which is connected to the pinion 91 through the opening groove of the guide base 92 and slides along the opening groove. , 94, and knob screws 95, 96 for fixing the racks 93, 94 on the guide base 92, respectively.

FIG. 7 is a sectional view showing a part of the structure of the pinch roller 18.

The pinch roller 18 has an outer layer 102 made of a rubber material formed on the outer surface of a pipe 101 made of an aluminum material, and has oil-impregnated bearings 10 at both ends thereof.
3 is press-fitted. The pinch roller shaft 104 is passed through the oil impregnated bearing 103, and the pinch roller shaft 10
4 to the pinch roller mounting frame 18-1
The pinch roller 18 is rotatably provided on the pinch roller mounting frame 18-1 while being fixed via 05.

FIG. 8 is a diagram showing the structure of the gap sensor 19.

The gap sensor 19 is formed of a molding material and is formed of the same molding material as the upper cover 111 in which the light emitting portion 19-1 of the optical transmission type sensor is built. Section 19-2 and optical reflection type sensor 19-3 are built-in, and a lower cover 112 having a nut portion formed therein, and a screw shaft 113 having a knob at its tip inserted into the nut portion. It consists of and. The screw shaft 113 is rotatably fixed to the main frame 48. Therefore, by rotating the knob of the screw shaft 113, the gap sensor 19 can be moved in the direction orthogonal to the sheet conveying direction.

A step formed at one end of the lower cover 112 to secure a gap required for detection of the transmissive sensors 19-1 and 19-2 and the reflective sensor 19-3. Is provided. A protrusion is formed near the center of the step, and the upper cover 111 and the lower cover 112 are joined to each other on the step with a predetermined angle formed by the protrusion with a screw.

The upper cover 111 is pushed down by the tip of the pinch roller frame 18-2 when the pinch roller frame 18-2 is set. At this time,
The upper cover 111 and the lower cover 112 are parallel to each other with a gap required for the transmissive sensors 19-1 and 19-2 and the reflective sensor 19-3 due to the step of the lower cover 112. Further, the optical axes of the light emitting portion 19-1 and the light receiving portion 19-2 of the transmissive sensor are secured.

In this embodiment having such a structure, the thermal head 25 as a print head is provided with a head mounting plate 41 as a pressure receiving member just above the position of the heating resistor, and this head is provided. A head pressing shaft 42 as a pressing shaft is fitted in a fitting hole of the mounting plate 41.
The head pressure shaft 42 includes a head pressure arm 43 as a groove member and a head pressure spring 44 as an elastic member.
Is rotatably supported by a fitting hole member.

The head pressure arm 43 is provided with a pressure mechanism including a head pressure cam 50, a head release shaft 51 and a first torsion spring 47, so that the thermal head 25 moves to the head-down position during pressure. When the pressure is released, the thermal head 25 is moved to the head-up position and separated from the platen 11 to release the pressure.

Further, the ribbon save plate 5 as a separating mechanism
7 is driven by a solenoid 56 as a separation driving means, the head pressing shaft 42 is lifted, and a ribbon save state is set.

The head blocks 7 (-10) are both rotatably supported by a head mounting member 54 on a fulcrum shaft 29, and the head mounting member 54 and the fulcrum shaft 29 are rotatably supported.
A rotating mechanism is constituted by the.

The head block 7 is rotated by this rotating mechanism to be separated from the platen 11 (to 14), and a gap is formed so that the head can be freely exchanged by inserting a human hand. It At this time, since the connecting part (one end) of the solenoid 56 of the ribbon save plate 57 to the plunger is formed in an arc shape, the joining part does not come off from the plunger.

In order to remove the thermal head 25, the head pressing shaft 42 is overcome by the urging force of the head pressing spring 44, lifted up, and removed from the groove of the head pressing arm 43 by one touch. You can

Further, when the head release shaft 51 and the head pressurizing cam 50 as a pressurizing mechanism are rotated to raise the head of the thermal head 25 (when the pressurization is released), the stopper 43-1 is used as the main part of the thermal head 25. Frame 4
Since the separation on the 8 side is limited, the thermal head 25 opens the insertion side of the ink ribbon magazine 3 (to 6) and tilts it.

As described above, according to the present embodiment, the pressure mechanism including the head pressure cam 50 and the head release shaft 51 is arranged in the arrangement direction of the heating resistors of the thermal head 25, so that the head blocks 7 to It is possible to reduce the length of the paper sheet 10 in the conveyance direction, and the color printer 1 can be downsized.

Further, from directly above the position of the heating resistor of the thermal head 25, the head mounting member 41, the head pressing shaft 42, the head pressing spring 44, the head pressing arm 43.
Since the pressure is applied by the head pressure cam 50 and the head release shaft 51 via the, the pressure loss does not occur.

Further, the thermal head 25 is supported by the head pressure shaft 42, the head pressure arm 43, and the head pressure spring 44, and pressure is applied via these, so that the head can be moved up and down with good reproducibility. The thermal head 25 can be positioned at a desired position, the thermal head 25 can be removed with one touch, and the replaceability of the thermal head 25 can be improved.

Since one end of the ribbon save plate 57 slidably joined to the plunger of the solenoid 56 is formed in an arc shape, the ribbon save plate 57 remains joined to the solenoid 56 even when the head block is opened. You can

Further, the head pressing arm 43 is attached to the stopper 4
The provision of 3-1 makes it easy to insert the ink ribbon magazines 3 to 6 by opening and tilting the thermal head 25 in the direction in which the ink ribbon magazines 3 to 6 are inserted in the head-up state. be able to.

Further, the thermal head 25 is composed of the substrate 25-1 and the heat radiating plate 25-2, and the heat radiating plate 25-2 is made large in size, the contact surface with the ink ribbon is widened, and the upper surface is horizontal. By forming it in the above-described manner, the heat dissipation effect and the effect of removing the static electricity of the ink ribbon can be improved, and the pressure applied to the thermal head 25 can act on the heating resistor without loss.

Further, since the head frame 46 is formed of an aluminum material into a substantially H shape, the strength of the head blocks 7 to 10 can be improved and at the same time,
The upper end can be used as a guide when the ink ribbon magazines 3 to 6 are mounted. Further, a fan can be attached to the upper surface of the head frame 46. If various cables are accommodated on the lower surface of the head frame 46, the routing of the cables can be organized, and if the ink ribbon magazines 3 to 6 are mounted, noise and static electricity can be prevented as a shield for the cables. .

[0099]

As described above in detail, according to the present invention,
By improving the pressure mechanism that presses the print head against the platen, it is possible to provide a small-sized printer that can perform high-precision printing.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a color printer according to an embodiment of the present invention.

FIG. 2 is a front view showing the configuration of a head block of the color printer of the embodiment.

FIG. 3 is a side view showing the configuration of a head block of the color printer of the embodiment.

FIG. 4 is a front view showing the configuration of an ink ribbon magazine of the color printer of the embodiment.

FIG. 5 is a side view showing a configuration of an ink ribbon magazine of the color printer of the embodiment.

FIG. 6 is a diagram showing a configuration of a center guide of the color printer of the embodiment.

FIG. 7 is a diagram showing a configuration of a pinch roller of the color printer of the embodiment.

FIG. 8 is a diagram showing a configuration of a gap sensor of the color printer of the embodiment.

[Explanation of Codes] 3 to 6 ... Ink Ribbon Magazine, 7 to 10 ... Head Block, 11 to 14 ... Platen, 16 ... Center Guide, 18 ... Pinch Roller, 19 ... Gap Sensor, 25-28 ... Thermal Head, 25- 3, 25-4 ... Head positioning plate, 29 ... Support shaft, 31 ... Paper guide member, 41 ... Head mounting member, 42 ... Head pressing shaft, 43 ... Head pressing arm, 43-1 ... Stopper, 44 ... Head Pressure spring, 46 ... Head frame, 47 ... Head positioning hole, 48 ... Main frame, 50 ... Head pressure cam, 51 ... Head release shaft, 54 ... Head block mounting member, 56 ... Solenoid, 57 ... Ribbon save plate , 60 ... Side frame, 61 ... Platen frame, 62-1, 62-2 ... Head positioning pin, 74 ... Winding up Side rollers, 75 ... Supply side rollers, 81 ... Loading table, 83 ... Paper guide member.

Claims (6)

[Claims] 1. A printer in which a sheet is inserted between a print head and a platen, and the print head prints on the sheet using an ink ribbon, and a pressure shaft provided on the print head, A printer comprising: a fitting hole member having a fitting hole into which a pressure shaft is rotatably fitted; and a pressure mechanism for applying pressure to the fitting hole member. 2. The printer according to claim 1, wherein
One end of the fitting hole member is rotatably supported, and a fitting hole into which the pressure shaft is rotatably fitted is formed at the other end. The fitting hole member and the pressing mechanism are A printer characterized in that the printer is arranged in a direction orthogonal to the sheet conveying direction. 3. A printer in which a sheet is inserted between a print head and a platen, and the print head prints on the sheet using an ink ribbon, the printer being provided on a center line passing through the center of gravity of the print head. A printer comprising: a pressure receiving member; and a pressure mechanism for pressing the pressure receiving member from above the center line. 4. The printer according to claim 2, wherein:
The fitting hole member is rotatably supported at one end, and has a groove member having an open groove at the other end, and a downward direction from above the pressing shaft housed in the groove member. A printer comprising: an elastic member for urging the elastic member, and the pressing mechanism presses the elastic member via the groove member. 5. A printer in which a sheet is inserted between a print head and a platen, and an ink ribbon is used by the print head to print on the sheet, the print head in contact with the platen being the platen. A separation mechanism that separates the separation head, a separation drive unit that is fixed to the apparatus main body side and that drives the separation mechanism, and a rotation mechanism that rotates the print head having the separation mechanism in a direction that separates it from the platen. And a connecting member for connecting the separating mechanism and the separating drive means has an arc shape corresponding to the rotation of the print head by the rotating mechanism. 6. A printer in which a sheet is inserted between a print head and a platen, and an ink ribbon is used to print on the sheet by the print head, the print head is brought into contact with the platen to apply pressure. A pressure mechanism that separates the pressure from the print head to release the pressure, and a separation distance of one end of the print head on the side opposite to the insertion direction of the ink ribbon when the pressure is released by the pressure mechanism. A stopper that limits the insertion of the ink ribbon to a minimum extent that does not hinder the separation of the other end of the print head on the ink ribbon insertion side from the other end of the print head. Characteristic printer.