JPH11334121A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To execute bi-directional printing in the inward direction and outward direction and to eliminate difference of printing quality between printing in the inward direction and printing in the outward direction by executing the bi-directional printing by the same pressing force. SOLUTION: A print head 6 is mounted on a carriage 5 such that it is supported to the carriage 5 rotationally in the scanning direction. A print head rotating means consisting of a head rotating gear 23, a motor gear 24 and a motor 25 is provided. The print head rotating means rotates the print head 6 by 180 deg. around an axis 22 perpendicular to a print head conveying face after printing in the inward direction and the outward direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer for printing an image on a sheet by thermal transfer, and more particularly, to a printer having improved print head transport means.

[0002]

2. Description of the Related Art FIG.
FIG. 8 is a schematic plan view showing a conventional printer disclosed in Japanese Patent Publication No. 8 (JP-A-8). In the figure, 1 is a platen, 2 is a sheet held on the platen 1, 3 is an ink sheet, 4a, 4
Reference character b denotes two guide shafts parallel to the platen 1 and reference numeral 5 denotes a carriage slidably supported by the guide shafts 4a and 4b. The carriage 5 reciprocates along the platen 1 by driving means (not shown). Is done.

Reference numeral 6 denotes a print head mounted on the carriage 5, reference numeral 7 denotes a head arm that holds the print head 6 at the tip, and reference numeral 8 denotes a support shaft that rotatably mounts the base of the head arm 7 to the carriage 5. , 9 is a return spring that urges the print head 6 away from the platen 1, 10 is a pressure arm having a cam engaging piece 10 a at the tip, and 11 is a rotatable base of the pressure arm 10 on the carriage 5. The supporting shaft 12 is attached to the tip of the pressure arm 10 on the opposite side of the cam engaging piece 10a and is movable in the direction of pressing the head arm 7, and 13 is the head pressing member. A compression spring 14 interposed between the arm 12 and the pressure arm 10 is a cam pivotally supported by the carriage 5 so as to be able to rotate in the forward and reverse directions. Cam engagement piece 10a of 10 abuts. 15 is a head cam gear that rotates synchronously with the cam 14, 16 is an idle gear that meshes with the head cam gear 15, 17 is a motor gear that meshes with the idle gear 16,
Reference numeral 18 denotes a head-up / down motor (hereinafter simply referred to as a motor) having the motor gear 17 and mounted on the carriage 5.

Next, the operation will be described. At the start of printing, the motor 18 is started and the cam 14 is driven to rotate in one direction while the print head 6 is at the initial print position, whereby the cam 14 pushes down the pressure arm 10 and the compression spring 13 The head presser 12 is connected to the head arm 7
Is pressed down against the return spring 9. As a result, the print head 6 at the tip of the head arm 7 is pressed against the paper 2 via the ink sheet 3, and the outward printing is performed while the carriage 5 is moved leftward in the figure by the driving means (not shown).

[0005] When the forward printing is completed, the print head 6 is raised at that time, and is driven by driving means (not shown).
After the carriage 5 moves rightward in the drawing and returns the print head 6 to the printing start point (initial printing position), the next forward printing is performed in the same manner.

FIG. 19 is a schematic front view showing the state of contact pressure between the print head and paper during forward printing in a general print head scanning type thermal transfer printer, and FIG. 20 shows the print head and paper during return printing in FIG. It is a schematic front view which shows a contact pressure state. Here, in general, when reciprocating scanning printing is performed by the print head 6 of the thermal transfer printer, the contact pressure of the print head 6 with the paper 2 is different between the forward printing and the backward printing, and an external force such as a frictional force accompanying the scanning of the print head 6 is obtained. Works. That is,
As shown in FIG. 19, at the time of forward printing, the contact pressure P of the print head 6 tends to decrease due to the influence of the external force q.
Also, as shown in FIG. 20, the contact pressure P of the print head 6 tends to increase due to the influence of the external force q 'during the backward printing.

[0007]

Since the conventional printer device is configured as described above, it is for one-way printing, and after the one-way scanning printing (forward printing), the print head 6 is initialized. There is a problem that the printing position has to be returned to the printing position, the printing time is increased by the return position, and the printing speed is reduced.

Further, if the conventional printer device performs reciprocating (bidirectional) printing, the contact pressure condition of the thermal head is different between the forward printing and the backward printing, so that the forward printing and the backward printing are not performed. Thus, there is a problem that a difference occurs in printing quality such as printing density. Further, in the above-described conventional printer device, a dedicated driving source (motor) is required for the up / down operation of the thermal head, and there are problems such as an increase in the number of parts and an increase in cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and can perform bidirectional printing of forward printing and backward printing, and can perform bidirectional printing under the same contact pressure condition. It is an object of the present invention to provide a printer capable of eliminating a difference in printing quality between forward printing and returning printing.

Further, the present invention provides a printer device which can change the direction of the print head between the forward print direction and the return print direction by its own scanning force, and can eliminate the need for a drive source dedicated to the print head, thereby reducing costs. The purpose is to gain.

Further, according to the present invention, it is possible to perform bidirectional printing of forward printing and backward printing under the same contact pressure condition,
An object of the present invention is to provide a printer device capable of improving print quality.

It is a further object of the present invention to provide a printer device which has no difference in print density between forward printing and backward printing in both directions, and provides high printing quality.

Further, according to the present invention, the influence of an external force such as a frictional force during the backward printing operation on the contact pressure between the print head and the paper is reduced as in the forward printing operation. An object of the present invention is to provide a printer device which can perform printing under the same contact pressure conditions in both directions.

Further, the present invention provides a printer device capable of setting the contact pressure between the print head and the paper to the same condition at the time of forward printing and at the time of backward printing, and eliminating the difference in print quality in reciprocating printing. The purpose is to:

A further object of the present invention is to provide a printer device which does not require a dedicated driving means such as a motor for the operation of contacting / separating the print head from the sheet and reduces the cost.

A further object of the present invention is to provide a printer device which can prevent wrinkles from occurring on an ink sheet and which can be expected to reduce costs without requiring extra parts.

[0017]

A printer device according to the present invention has a print head for recording an image on a sheet via an ink ribbon, and the print head is mounted and driven to scan back and forth in a printing direction on the sheet. In a printer device including a carriage and a print head contacting / separating unit that causes the print head to contact / separate the paper, the carriage is provided on the carriage, and supports the print head rotatably in a scanning direction, Further, a print head rotating means is provided for rotating the print head by 180 ° about the axis perpendicular to the print head transport surface after the completion of the forward printing and the return printing.

In the printer according to the present invention, the print head rotating means includes a gear provided on the carriage having a one-way clutch, a forward print end point and a return print end point in the printer body other than the carriage. And a gear engaging means for engaging and rotating the gear by the scanning and conveying force of the print head to displace the print head by 180 ° in the print head scanning direction.

A printer device according to the present invention includes a print head for recording an image on a sheet via an ink ribbon, a carriage mounted with the print head and driven to reciprocate in a printing direction on the sheet, and the print head. A print head contacting / separating means for causing the print head to move toward and away from the paper, after the forward printing operation by the forward scanning of the print head is completed, the print head is scanned in the reverse direction to the backward scanning direction. A contact pressure control means is provided for controlling the contact pressure between the print head and the paper when performing the backward printing operation so as to be lower than the contact pressure during the forward scan of the print head.

A printer device according to the present invention includes a print head for recording an image on a sheet via an ink ribbon, a carriage mounted with the print head and driven to reciprocate in a printing direction on the sheet, and the print head. A print head contacting / separating means for causing the print head to move toward and away from the paper, after the forward printing operation by the forward scanning of the print head is completed, the print head is scanned in the reverse direction to the backward scanning direction. Control means is provided for controlling the drive time of the print head so that the applied energy of the print head when performing the backward printing operation is smaller than that during the forward printing operation of the print head.

According to the present invention, there is provided a printer head for recording an image on a sheet via an ink ribbon, a carriage mounted with the print head and driven to reciprocate in a printing direction on the sheet, and the print head. A print head contacting / separating means for moving the print head toward and away from the paper, wherein the print head is rotated about an arbitrary point in a plane orthogonal to the paper and parallel to the print head scanning direction. The print head is configured such that the center of rotation of the print head at the time of forward printing operation and at the time of backward printing operation is based on a plane orthogonal to the paper through the point of action of the contact pressure between the print head and the paper. A print head contact / separation means for changing the rotation center of the print head so as to be located on the print head scanning direction side is provided.

In the printer device according to the present invention, the rotation center of the print head is perpendicular to the sheet through the point of application of the contact pressure between the print head and the sheet during the forward printing operation and the backward printing operation. In this configuration, the position is changed to a position that is symmetrical with respect to the plane to be formed.

A printer device according to the present invention includes a print head for recording an image on a sheet via an ink ribbon, a carriage mounted with the print head and driven to reciprocate in a printing direction on the sheet, and the print head. And a print head contacting / separating means for causing the paper head to contact / separate the paper.
A cam follower provided in the print head unit, a cam member provided in the print head unit for guiding the cam follower to separate the print head from the paper, and holding the print head in a separated state; and the carriage. And a print head separation releasing means for releasing the separated state of the print head and the paper.

In the printer according to the present invention, the cam follower is formed to be longer than the width of the ink sheet so as to contact the ink sheet at right angles to the printing direction.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a perspective view showing a main part of a printer according to Embodiment 1 of the present invention, and FIG. 2 is a front view of FIG. 1. The same reference numerals are used for the same or corresponding parts as in FIGS. And duplicate explanations are omitted. 1 and 2, reference numeral 1 denotes a sheet-like platen, and 4 denotes a single guide shaft parallel to the platen 1, and a carriage 5 is slidably held on the guide shaft 4. Reference numeral 19 denotes an idler pulley rotatably supported by a printer unit (hereinafter referred to as an apparatus main body). Reference numeral 20 denotes a wire wound around the idler pulley 19 and connected to the carriage 5. The carriage 5 is reciprocally scanned and driven along the guide shaft 4 by driving means (motor) (not shown).

Reference numeral 21 denotes a head holder rotatably held by the carriage 5. A head arm 7 is held by a lower part of the head holder 21 via a support shaft 8 so as to be vertically rotatable. And the head holder 2
1, a head pressure spring (compression spring) 13 is interposed.

Reference numeral 22 denotes a head rotation shaft which is integrally connected to the lower end of the head holder 21 and is rotatably mounted on the carriage 5. The head rotation shaft 22 carries the print head 6 by scanning the carriage 5. Consists of an axis perpendicular to the plane. Accordingly, the print head 6 held by the head arm 7 is rotatable about the head rotation shaft 22.

Reference numeral 23 denotes a head rotating gear integrally connected to the upper end of the head rotating shaft 22, 24 denotes a motor gear meshing with the head rotating gear 23, and 25 denotes a motor having a motor gear 24 connected to an output shaft. Motor 25
Constitutes a print head rotating means for rotating the print head 6 through 180 ° after the completion of the forward printing and the return printing via the motor gear 24, the head rotating gear 23 and the head rotating shaft 22.

Reference numeral 7a denotes a follower integrally projecting from the free end side of the head arm 7, and reference numerals 26 (see FIG. 2) are disposed at the forward and backward printing end points of the print head 6 in the apparatus body. A pair of left and right (only one is shown in FIG. 2) head-up cams 26a for guiding the follower 7a are tapered cam surfaces of the head-up cam 26, and the follower 7a is provided on the cam surface 26a.
, The print head 6 for the paper 2
Is released.

Here, after the follower 7a rides on the head-up cam 26, the motor 25 displaces the print head 6 by 180 ° with respect to the scanning direction. When the follower 7a separates from the cam surface 26a of the head-up cam 26 by scanning after the print head 6 is displaced by 180 °, the print head 6 is pushed down by the head pressure spring 13 so that
A contact pressure is applied to the paper 2 via the ink sheet (ink ribbon) 3. Therefore, the follower 7a, the head-up cam 26, and the head pressure spring 13 constitute a print head contact / separation unit for causing the print head 6 to move toward and away from the paper 2. In FIG. 2, reference numeral 27 denotes a spacer provided between the carriage 5 and the head holder 21.

Next, the operation will be described. 3A and 3B are explanatory views of the operation of FIGS. 1 and 2. FIG. 3A is a front view showing a state at the time of forward printing, and FIG. 3B is a view showing a head-up state of the print head at the end point of forward printing. Front view, FIG. 3
(C) is a front view showing the state at the time of return printing. At the time of the printing operation, the print head 6 held by the head arm 7 is pressed down by the head pressure spring 13, and the state shown in FIG. In this state, the carriage 5 is conveyed along the guide shaft 4 in the direction of the arrow in FIG. 2A by driving means (not shown) via the wire 20, and the print head 6 scans the ink sheet 3 in the forward path. As a result, forward printing on the paper 2 is performed.

When the carriage 5 reaches the forward printing end point, the follower 7a of the head arm 7 rides on the cam surface 26a of the head-up cam 26 at that position, and the follower 7a further moves on the cam surface 26a. By moving in the direction of the arrow 2 (a), the head arm 7 is lifted up with the support shaft 8 as a fulcrum, and the contact pressure of the print head 6 with the paper 2 is released. After the release of the contact pressure, the carriage 5 is stopped, and at this time, the ink sheet 3 is wound up by a driving unit (not shown), and the forward printing operation is completed.

After the forward printing operation is completed, the motor 25 is started, and its rotating force is transmitted to the head rotating shaft 22 via the motor gear 24 and the head rotating gear 23, whereby the head perpendicular to the print head transport plane is moved. Rotary axis 2
2, the head holder 21 and the print head 6 rotate together (see FIG. 2B). And head holder 2
When 1 rotates by 180 °, the motor 25 automatically stops. After the stop, the carriage 5 is moved to the position shown in FIG.
The carriage is driven in the direction indicated by the arrow (c) to perform a return printing operation.

When the carriage 5 reaches the return printing end point (print start position) by the return printing operation, the follower 7a of the head arm 7 rides on the head-up cam 26 at that position, and the print head 6 contacts the paper 2. The pressure is released, and after the contact pressure is released, the motor 25 is activated and the head holder 21 is rotated by 180 ° about the head rotation axis 22 perpendicular to the print head transport plane, as in the case of the end of the forward printing described above. After the motor 25 is stopped at its 180 ° rotation position, the carriage 5
Is transported again in the direction of the arrow in FIG.
Forward printing is performed again.

According to the first embodiment described above, the print head 6 is displaced by 180 ° about the head rotating shaft 22 perpendicular to the print head transport plane after the forward printing and the return printing. As a result, the print head 6 can perform both forward printing and returning printing on the paper 2 in the same direction under the same contact pressure condition, so that there is no difference in print quality between forward printing and returning printing. There is. Further, the print head 6 is moved by the head-up cam 26 at the forward print end point and the return print end point, the follower 7a of the head arm 7, and the head pressure spring 13.
Since the print head contacting / separating means for moving the print head 6 to / from the paper 2 is configured, a dedicated driving source (motor) is not required for the up / down operation of the print head 6, so that the cost can be reduced. .

Embodiment 2 FIG. 4 is a plan view showing a main part of the printer device according to the second embodiment of the present invention at an end point of forward printing, and FIG. 5 is a plan view showing a main part of the printer device of FIG. In FIG. 4, reference numeral 28 denotes a one-way clutch attached to the head rotating shaft 22. The one-way clutch 28 rotates the head rotating shaft 22 synchronously when rotating in one direction, and rotates the head rotating shaft 22 when rotating in the other direction. It spins around.

In FIG. 4, reference numeral 29a denotes a rack gear arranged at the end of forward printing in the apparatus main body, and the rack gear 29a is engaged with the head rotating gear 23 which has reached the end of forward printing. In FIG.
Reference numeral 29b denotes a rack gear arranged at the end point of the backward printing in the apparatus main body. The rack gear 29b is engaged with the head rotating gear 23 which has reached the end point of the backward printing. These rack gears 29a and 29b are arranged at positions symmetrical with respect to a straight line passing through the head rotation shaft 22 parallel to the transport plane of the print head 6 and parallel to the head transport direction, and the head rotary gear 23 is used to complete forward printing. The gear engagement means is engaged at the point and the return path printing end point. The other configuration is the same as that of the first embodiment, and the description is omitted.

Next, the operation will be described. FIG. 5A is a front view showing an operation state at the end point of forward printing, and FIG.
FIG. 6B is a front view showing an operation state in a return printing direction from a forward printing end point, FIG. 6A is a front view showing an operation state at a return printing end point, and FIG. 6B is a return printing end point. FIG. 9 is a front view showing an operation state in a forward print direction from the direction shown in FIG. When the carriage 5 reaches the return printing end point, the head rotating gear 23 engages with the rack gear 29a, and the carriage 5 is further transported in the direction of the arrow A in FIG. The rotating shaft 22 is rotated synchronously with the head rotating gear 23 by a one-way clutch 28 attached to the head rotating gear 23. This causes the print head 6 to rotate together with the head holder 21 in the counterclockwise direction in FIG. 5A around the head rotation shaft 22 perpendicular to the head transport plane.

Then, when the print head 6 is rotated by 180 °, the carriage 5 is temporarily stopped in the forward printing direction, and then moved in the backward printing direction (in the direction of arrow B in FIG. 5B). ). At this time, the head rotating gear 23 rotates in the direction of the dashed arrow in FIG. 5B due to engagement with the rack gear 29a, but the one-way clutch 28 attached to the head rotating gear 23 causes the head rotating gear 23 to rotate. It idles around the axis 22.

When the carriage 5 reaches the return printing end point, the head rotating gear 2 is attached to the rack gear 29b at that point.
3 are engaged, and the carriage 5 is
When the print head 6 is further conveyed in the direction indicated by the arrow B in FIG. 7A, the head rotation shaft 22 rotates synchronously with the head rotation shaft 23 by the one-way clutch 28, and the print head 6 and the head holder 21 are perpendicular to the head conveyance plane. Head rotation axis 2
6 rotates in the counterclockwise direction in FIG.

In this way, if the print head 6 is rotated by 180 ° at the end point of the backward printing, the carriage 5 is temporarily stopped in the backward printing direction at that point, and then stopped.
This time, the carriage 5 is transported and driven in the outward printing direction (the direction of arrow A in FIG. 6B). At this time, the head rotating gear 23 is engaged with the rack gear 29a to
Although the head rotates in the direction indicated by the dashed arrow in FIG.
The head rotating gear 23 idles around the head rotating shaft 22 by a one-way clutch 28 attached to the motor 3.

According to the second embodiment described above, the print head 6 is rotated about the head rotation axis 22 perpendicular to the head transport plane by the transport force of the carriage 5 itself, and thus is described in the first embodiment. There is an effect that driving means such as the motor 25 can be made unnecessary and cost can be reduced.

Embodiment 3 FIG. 7 is a front view showing a printer device according to Embodiment 3 of the present invention. In the drawing, reference numeral 30 denotes a head cam attached to the carriage 5,
A cam shaft 31 is fixed to the carriage 5 and rotatably supports the head cam 30. A guide roller 32 is rotatably supported at the tip of the head cam 30. A reference numeral 33 designates the head cam 30 in one direction. A coil spring that biases and regulates the position of the head cam 30;
One end of the coil spring 33 is fixed to the carriage 5 and the other end is fixed to the head cam 30. Reference numeral 34 denotes a roller guide disposed at a start point of forward printing and a start point of return printing in the apparatus main body, 34a denotes an inclined portion formed in the middle of the roller guide 34, and 34b denotes a concave portion connected to the inclined portion 34a. The other configuration is the same as that of the first embodiment, and the description is omitted.

That is, in the printer device according to the third embodiment, after the forward print operation by the forward scan of the print head 6 is completed, the print head 6 is scanned in the reverse direction to the backward scan direction to perform the backward print operation. The head cam 30, the guide roller 32, the coil spring 33 and the roller are used as contact pressure control means for controlling the contact pressure between the print head 6 and the paper 2 to be lower than the contact pressure of the print head 6 during forward scanning. A guide 34 is provided.

Next, the operation will be described. FIG. 8A is a front view showing an operation state in the forward printing direction, and FIG. 8B is a front view showing an operation state in the backward printing direction. At the time of the forward printing operation, as shown in FIG. 8A, the guide roller 32 moves along the roller guide 34 while rotating in contact with the roller guide 34, so that the head cam 3 is moved.
0 is the camshaft 31 against the elastic force of the coil spring 33
, The base end portion 30a of the head cam 30 comes into contact with the head holder 21 to push down the head holder 21. Thereby, the head pressure spring 13
The print head 6 presses the paper 2 through the head pressure (contact pressure)
give. At this time, a force for rotating the head cam 30 in the direction opposite to the direction A is exerted on the head cam 30 by the coil spring 33.

When the carriage 5 reaches the end point of the forward printing, the carriage 5 is positioned on the left side of the sheet 2 in FIG.
The head cam 30 rotates around the cam shaft 31 by the restoring force of the coil spring 33 and returns to the initial state. Here, when the carriage 5 is conveyed and driven by a driving source and a driving unit (not shown) in the backward printing direction (the direction of arrow B in the drawing) shown in FIG. 8B, the guide roller 32 rotates along the roller guide 34. By moving, the head cam 30 rotates counterclockwise around the camshaft 31, the base end 30b of the head cam 30 abuts on the head holder 21, and the head holder 21 is pushed down. As a result, a head pressure is applied between the print head 6 and the paper 2 via the head pressure spring 13.

Since the radius r from the center of the camshaft 31 to the base end 30a of the head cam is larger than the radius r 'from the center of the camshaft 31 to the base end 30b of the head cam, the forward printing is performed as compared with the return printing. At this time, the displacement amount of the head pressure spring 13 is larger. That is, FIG.
As described above, the contact pressure P of the print head 6 tends to decrease during forward printing, and the contact pressure P of the print head 6 tends to increase during return printing as described in FIG. is there. As a result, the head pressure at the time of forward printing becomes larger than the head pressure at the time of backward printing, and there is no difference between the contact pressure at the time of forward printing and the pressure at the time of backward printing.

According to the third embodiment described above, the head pressure spring 13 at the time of backward printing is controlled by the head cam 30.
Can be set smaller than the displacement of the head pressure spring 13 at the time of forward printing, whereby the bidirectional printing of forward printing and return printing can be performed under the same contact pressure condition. is there.

Embodiment 4 FIG. 9 is a table showing the relationship between the applied energy to the print head and the print density during the forward printing and during one printing cycle of the backward printing of the printer according to the fourth embodiment of the present invention, and FIG. FIG. 4 is a time chart illustrating the energization time to the print head during printing and return printing. As shown in FIG. 9, when the applied energy to the print head 6 is the same during forward printing and backward printing, the print density is higher during backward printing. In order to obtain the same print density in both round-trip printing, in FIG.
The energy applied to the print head 6 during forward printing is E1, and the energy applied to the print head 6 during backward printing is E1.
As E2, E1> E2 may be satisfied. Further, as shown in FIG. 10, the print head 6 during one recording cycle f during forward printing.
The energizing time t2 to the print head 6 during one recording cycle at the time of backward printing is set to be shorter than the energizing time t1 to the head.

According to the fourth embodiment, the energization time t2 to the print head 6 during one recording cycle during backward printing is set to be longer than the energization time t1 to the print head 6 during one recording cycle f during forward printing. By setting the number to a small value, there is an effect that it is possible to obtain a print quality having no difference in print density in both round-trip printing.

Embodiment 5 FIG. FIG. 11 is a perspective view showing a printer device according to Embodiment 5 of the present invention, and FIG.
12 is a front view showing the forward printing operation state of FIG. 11, and FIG.
FIG. 12B is a front view illustrating an operation state at the end point of the outward printing in FIG. 11. In the figure, a head support arm 35 has a head arm shaft 36 for forward printing that rotatably supports the head arm 7 that supports the print head 6. The head support arm 35 is provided on the carriage 5. It is supported by the head arm shaft 37 for homeward printing. Here, the contact point S between the print head 6 and the paper 2 (FIG. 1)
2 (a), the forward print head arm shaft 36 is disposed on the forward transfer direction, and the return print head arm shaft 37 is disposed on the return transfer direction.

Reference numeral 38 denotes a head lever attached to the head support arm 35, and 39 denotes a head lever shaft protruding from the abdomen of the head support arm 35. The head lever shaft 39 allows the head lever 38 to rotate freely. It is supported by.

FIG. 13A is a front view showing the state of the return printing operation in FIG. 11, and FIG. 13B is a front view showing the operation state at the end point of the return printing in FIG. In the figure, 38
a and 38b are notches provided on the head lever 38,
Numeral 0 denotes a projection provided on the carriage 5, and 7 b denotes a projection provided on the head arm 7.
a, 38b are configured to engage with each of the protrusions 40 and 7b. Reference numeral 41a denotes a head lever pressing member disposed near the end point of forward printing on the apparatus main body other than the carriage 5, and 41b denotes a head lever pressing member disposed near the end point of return printing on the apparatus main body. Note that other configurations are the same as those of the first embodiment.
Therefore, the description is omitted.

Next, the operation will be described. During the forward printing operation, one notch 38a of the head lever 38 is engaged with the projection 40 as shown in FIG.
The head support arm 35 is fixed to the carriage 5. In this state, the other notch 38b of the head lever 38 is disengaged from the projection 7b on the head arm 7, and the head arm 7 is approximately
(A) connects the center of the head arm shaft 36 for forward printing and the contact point S between the center of the print head 6 and the paper 2 as shown in FIG. Is done. Therefore, the contact pressure of the print head 6 tends to decrease during forward printing as in FIG.

After the forward printing is completed, the carriage 5 is conveyed and driven in the forward printing direction by a driving means (not shown), so that the head lever pressing member 41a moves the head lever 38 as shown in FIG. Abut. As a result, the head lever 38 rotates about the head lever shaft 39, and the engagement between the one notch 38a on the head lever 38 and the projection 40 is released, and the other notch on the head lever 38. 38b engages with the protrusion 7b on the head arm 7.

Therefore, the fixing of the head support arm 35 to the carriage 5 is released, and the head support arm 3
Numeral 5 is supported rotatably about the head arm shaft 37 for homeward printing, and the head arm 7 is fixed to the head support arm 35. In this state, the carriage 5 is driven and transported in the direction of the arrow in FIG.

At the time of the backward printing, the head arm 7 is fixed to the head supporting arm 35, and in this state, the head supporting arm 35 is moved around the return printing head arm shaft 37 relative to the carriage 5 to approximately move. Figure 13
(A) the center of the head arm shaft 37 for backward printing,
The print head 6 is supported so as to be rotatable in an R-axis direction orthogonal to a straight line connecting a contact point S between the print head 6 and the paper 2. Therefore, the contact pressure of the print head 6 tends to decrease during the backward printing as well as during the forward printing.

After completion of the backward printing, the carriage 5 is further transported in the backward printing direction by a driving means (not shown), as shown in FIG.
The head lever 38 comes into contact with the head lever pressing member 41b. As a result, the head lever 38 rotates about the head lever shaft 39, and the engagement between the one notch 38b on the head lever 38 and the projection 7b on the head arm 7 is released, and the head lever 38 The other notch 38a is engaged with the projection 40, thereby completing the preparation for the forward printing operation in the next step.

According to the fifth embodiment described above, in the reciprocating path printing operation, the center of rotation of the head arm 7 holding the print head 6 with respect to the carriage 5 is positioned with respect to the contact point between the print head 6 and the paper 2. The contact pressure during printing by the print head 6 tends to decrease in both round-trip printing as well as in the transport direction side of the print head 6. And the difference in printing quality between forward printing and backward printing is reduced.

Embodiment 6 FIG. FIG. 14 is a front view showing a printer device according to Embodiment 6 of the present invention. The sixth embodiment is a modification of the fifth embodiment, and the same parts as those in the fifth embodiment are denoted by the same reference numerals. That is, in the sixth embodiment, the head arm shaft 36 for forward printing and the head arm shaft 37 for backward printing
14 are arranged at positions symmetrical with respect to a plane passing through the contact point S between the print head 6 and the paper 2 and orthogonal to the printing direction. The distance to the head arm axis 36 and the head arm axis 37 for the homeward printing are each one. The other configuration is the same as that of the fifth embodiment, and the description is omitted.

According to the sixth embodiment, the print head 6
The carriage 5 of the print head 6 from the contact point S between
, The distance between the print head 6 and the rotation axis of the print head 6 is the same for forward printing and return printing, so that the contact pressure between the print head 6 and the paper 2 is the same for both reciprocating printing. There is an effect that a difference in printing quality in road printing can be eliminated.

Embodiment 7 FIG. 15A is a front view showing a printer according to Embodiment 7 of the present invention.
15B is a partially enlarged view of FIG. 15A, FIG. 16A is a front view for explaining a separating operation between the print head and the recording paper in FIG. ) Is FIG.
It is a front view for demonstrating the separation | release operation | movement of (2). In the figure, reference numeral 42 denotes a cam lever.
Is supported rotatably about a cam lever shaft 43 provided on the carriage 5.
Surface 42a for guiding the cam follower 7c provided on the
And a concave cam surface 42b. The cam lever 42 has a distance m between the cam lever shaft 43 and the cam surface 42b when the print head 6 is in contact with the paper 2.
, And a distance m ′ from the cam lever shaft 43 to the cam follower 7c is such that m <m ′. Reference numeral 44 denotes a tension spring for assisting the operation of releasing the print head 6 from the sheet 2 from the separated state. The other configuration is the same as that of the first embodiment, and the description is omitted.

Next, the operation will be described. As shown in FIG. 15, during the printing operation, the cam surface 42 of the cam lever 42 is
a, 42b and the cam follower 7c on the head arm 7 are disengaged, and in the disengaged state, the print head 6 and the paper 2 are in contact. Then, at the printing end point, as shown in FIG. 16A, the lever pressing member 41a contacts the cam lever 42, and the cam lever 42 rotates around the cam lever shaft 43 in the clockwise direction in the figure. The cam surface 42a abuts and engages the cam follower 7c. When the carriage 5 is driven and conveyed in the direction of arrow A in FIG. 16A from the engagement point by a driving means (not shown), the rotation amount of the cam lever 42 increases, and the cam follower 7c is guided by the cam surface 42a to be cam follower. When the carriage 7c is guided to the cam surface 42b, the conveyance of the carriage 5 is stopped. At this time, the distance m between the cam lever shaft 43 and the cam surface 42b and the distance m 'between the cam lever shaft 43 and the cam follower 7c when the print head 6 is in contact with the paper 2 are m <m'. Therefore, the print head 6 is separated from the paper 2.
Further, since the cam surface 42b has a concave shape, the cam follower 7c and the cam surface 42b are engaged, and the print head 6 and the paper 2 are kept separated.

When the carriage 5 is moved in the direction of arrow B in the drawing and returned to the printing start point in the state in which the print head 6 and the paper 2 are kept separated from each other, the cam lever 42 becomes a lever pressing member. By contacting the cam lever 42 with the cam lever shaft 43,
6 (b), the engagement between the concave cam surface 42b and the cam follower 7c is released, and the print head 6 comes into contact with the paper 2 again.

According to the seventh embodiment described above, the printing head 6 and the paper 2 are brought into and out of contact with each other by the conveyance force of the carriage 5. This eliminates the need for this, and thus has the effect of reducing costs.

Embodiment 8 FIG. FIG. 17 is a front view showing a printer device according to Embodiment 8 of the present invention. The eighth embodiment is a modification of the seventh embodiment, in which the cam follower 7c on the head arm 7 is longer than the width of the ink sheet 3, and the ink follower is orthogonal to the printing direction and in the printing state. The cam follower 7c is arranged so as to be in contact with the seat 3. Note that other configurations are the same as those of the above-described seventh embodiment, and thus description thereof will be omitted.

According to the eighth embodiment, since the cam follower 7c longer than the width of the ink sheet 3 is in contact with the ink sheet 3 during the printing operation, it is possible to prevent the ink sheet 3 from wrinkling. effective. Further, since the cam follower 7c serves as a guide for the ink sheet 3, there is an effect that no extra parts are required and cost reduction can be expected.

[0068]

As described above, according to the present invention, a print head rotating means for displacing the print head by 180 ° with respect to the scanning direction of the print head is provided. Since the print head is rotated by 180 ° about an axis perpendicular to the print head transport plane, it is possible to print in both directions, forward printing and returning printing, and to perform the printing in both directions under the same contact pressure conditions. For this reason, there is an effect that there is no difference in printing quality between forward printing and returning printing.

According to the present invention, since the print head is rotated by 180 ° about the axis perpendicular to the print head transport plane by the print head scanning force, a drive source such as a motor dedicated to print head rotation can be eliminated. This has the effect of reducing costs.

According to the present invention, after the print operation by the print head in the forward scan is completed, the print head is scanned in the direction opposite to the print head scan direction to perform the print operation by the backward scan in the print head. And control means for controlling the contact pressure between the paper and the paper so as to be lower than the print head contact pressure during forward scanning, so that printing is performed under the same contact pressure condition as reciprocating printing. This makes it possible to eliminate the difference in printing quality between forward printing and returning printing.

According to the present invention, the energy applied by the print head when performing the return printing operation by scanning the print head in the direction opposite to the print head scanning direction after the printing operation by the forward scanning of the print head is completed. Since the control means for controlling the driving time of the print head is provided so as to be smaller than that at the time of the printing operation by the head forward scanning,
In both round-trip printing, there is an effect that print quality having no difference in print density can be obtained.

According to the present invention, the print head contacting / separating means is configured to be capable of rotating the print head about an arbitrary point in a plane perpendicular to the paper and parallel to the print head scanning direction. At the time of the printing operation and the backward printing operation, the center of rotation of the print head passes through the point of application of the contact pressure between the print head and the paper and is positioned on the print head scanning direction side with respect to a plane orthogonal to the paper. As described above, since the rotation center of the print head is changed, the influence on the contact pressure between the print head and the paper due to external force such as frictional force during the return printing operation is similar to that of the print head during the forward printing. The contact pressure with the paper tends to decrease, and printing can be performed under the same contact pressure conditions in both round-trip printing and, therefore, there is an effect that there is no difference in printing quality between forward printing and backward printing.

According to the present invention, the rotation centers of the print head during the forward printing operation and the backward printing operation are respectively positioned on the print head scanning direction side, and the point of action of the contact pressure between the print head and the paper is set. The distance from the point of contact between the print head and the paper to the axis of rotation of the print head is different between the forward print and the return print. As a result, the contact pressure between the print head and the paper is the same for both round-trip printing and there is an effect that there is no difference in print quality in round-trip printing.

According to the present invention, the cam follower to the print head, the cam member for guiding the cam follower to separate the print head from the paper and maintain the separated state, and the print head and the paper to the printer unit other than the carriage. A release member is provided to release the state of separation between the print head and the paper. There is no need to provide a driving means, and there is an effect that cost reduction can be expected.

According to the present invention, during the printing operation, the cam follower longer than the width of the ink sheet is configured so as to be orthogonal to the printing direction and to contact the ink sheet.
This has the effect of preventing wrinkles from occurring in the ink sheet. Further, since the cam follower serves as a guide for the ink sheet, there is an effect that extra parts are not required and cost reduction can be expected.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a main part of a printer device according to a first embodiment of the present invention.

FIG. 2 is a front view of FIG.

FIGS. 3A and 3B are explanatory views of the operation of the printer device according to the first embodiment of the present invention, wherein FIG. 3A is a front view showing a state during forward printing, and FIG. FIG. 3C is a front view showing the state, and FIG.

FIG. 4 is a plan view illustrating a main part of a printer device according to a second embodiment of the present invention at an end point of forward printing.

FIG. 5A is a front view showing an operation state at a forward printing end point, and FIG. 5B is a front view showing an operation state in a backward printing direction from the forward printing end point.

FIG. 6A is a front view showing an operation state at a return printing end point, and FIG. 6B is a front view showing an operation state from the return printing end point in a forward printing direction.

FIG. 7 is a front view showing a printer device according to Embodiment 3 of the present invention.

8A and 8B are explanatory diagrams of the operation of FIG. 7, wherein FIG. 8A is a front view showing an operation state in a forward printing direction, and FIG. 8B is a front view showing an operation state in a backward printing direction.

FIG. 9 is a table showing the relationship between the energy applied to the print head and the print density during forward printing and during one printing cycle of return printing of the printer according to the fourth embodiment of the present invention.

FIG. 10 is a time chart showing the power supply time to the print head during forward printing and backward printing in one recording cycle in FIG. 9;

FIG. 11 is a perspective view showing a printer device according to a fifth embodiment of the present invention.

12A is a front view showing a forward printing operation state in FIG. 11, and FIG. 12B is a front view showing an operating state at a forward printing end point in FIG.

13 (a) is a front view showing a return printing operation state in FIG. 11, and FIG. 13 (b) is a front view showing an operation state at a return printing end point in FIG.

FIG. 14 is a front view showing a printer device according to Embodiment 6 of the present invention.

FIG. 15A is a front view showing a printer according to a seventh embodiment of the present invention, and FIG. 15B is a partially enlarged view of FIG.

FIG. 16A is a front view for explaining the separating operation between the print head and the recording paper in FIG.
FIG. 17B is a front view for explaining the separation releasing operation of FIG.

FIG. 17 is a front view showing a printer device according to an eighth embodiment of the present invention.

FIG. 18 is a schematic plan view showing a conventional printer disclosed in JP-A-2-185448.

FIG. 19 is a schematic front view showing a contact pressure state between a print head and a sheet during forward printing in a general print head scanning type thermal transfer printer.

20 is a schematic front view showing the state of the contact pressure between the print head and the paper at the time of backward printing in FIG. 19;

[Explanation of symbols]

2 paper, 3 ink sheet (ink ribbon), 5 carriage, 6 print head, 7c cam follower, 13
Head pressure spring (print head contact / separation means), 22 head rotation axis (vertical to the print head transport surface), 23 head rotation gear (print head rotation means), 24 motor gear (print head rotation means), 25 motor (printing) Head rotation means), 26 head-up cam (print head contact / separation means), 28 one-way clutch, 29a, 29b rack gear (gear engagement means), 30 head cam (contact pressure control means), 32 guide roller (contact pressure control means) ), 33
Coil spring (contact pressure control means), 34 Roller guide (contact pressure control means).

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B41J 25/304

Claims (8)

[Claims] 1. A print head for recording an image on a sheet via an ink ribbon, a carriage mounted with the print head and driven to scan back and forth in a printing direction on the sheet,
A printer device provided with a print head contacting / separating means for causing the print head to contact / separate from the paper, provided on the carriage, supporting the print head rotatably in a scanning direction, and A printer device comprising: a print head rotating means for rotating a print head by 180 ° about an axis perpendicular to a print head transport surface after completion of forward printing and return printing. 2. A print head rotating means provided at a carriage provided with a one-way clutch on a carriage, and at a print end point in a forward direction and a print end point in a return path in a printer main body other than the carriage, and 2. A printer device according to claim 1, further comprising gear engaging means for engaging and rotating said gear by a scanning conveyance force of said head to displace said print head by 180 DEG in a print head scanning direction. . 3. A print head for recording an image on a sheet via an ink ribbon, a carriage mounted with the print head and driven to scan back and forth in a printing direction on the sheet,
A print head contacting / separating means for causing the print head to move toward and away from the paper, after the forward print operation by forward scan of the print head is completed, the print head is moved in a direction opposite to the backward scan direction. The contact pressure between the print head and the paper when performing the return printing operation by scanning,
A printer device comprising: a contact pressure control unit that controls the contact pressure to be lower than the contact pressure of the print head during forward scanning. 4. A print head for recording an image on a sheet via an ink ribbon, a carriage mounted with the print head and driven to scan back and forth in a printing direction on the sheet,
A print head contacting / separating means for causing the print head to move toward and away from the paper, after the forward print operation by forward scan of the print head is completed, the print head is moved in a direction opposite to the backward scan direction. Control means for controlling the drive time of the print head so that the applied energy of the print head when performing the backward printing operation by scanning is smaller than during the forward printing operation of the print head. Printer device. 5. A print head for recording an image on a sheet via an ink ribbon, a carriage mounted with the print head and driven to scan back and forth in a printing direction on the sheet,
A print head contacting / separating means for causing the print head to move toward and away from the paper, wherein the print head is positioned at an arbitrary point on a plane orthogonal to the paper and parallel to the print head scanning direction. The print head is configured to be rotatable, and the rotation center of the print head during the forward printing operation and the return printing operation is a plane orthogonal to the paper through the point of application of the contact pressure between the print head and the paper. A printer apparatus comprising: a print head contact / separation unit that changes a rotation center of the print head so as to be positioned on a print head scanning direction side with respect to a reference. 6. A rotation center of the print head is symmetrical with respect to a plane orthogonal to the sheet through an action point of a contact pressure between the print head and the sheet during the forward printing operation and the backward printing operation. 4. The printer device according to claim 3, wherein the printer device is configured to be changed to a position as follows. 7. A print head for recording an image on a sheet via an ink ribbon, a carriage mounted with the print head and driven to scan back and forth in a printing direction on the sheet,
A print head contacting / separating means for causing the print head to contact / separate the paper with respect to the paper, wherein the print head contacting / separating means includes a cam follower provided in the print head unit, and a print head unit. Provided, a cam member for guiding the cam follower to separate the print head from the paper, and a cam member for holding the print head in the separated state, and a printer member other than the carriage,
A printer device comprising: a print head separation canceling unit that cancels a separation state between the print head and the sheet. 8. The printer device according to claim 7, wherein the cam follower is formed longer than the width of the ink sheet so as to contact the ink sheet at right angles to the printing direction.