JP2830982B2 - Thermal printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer used as a print output device such as a word processor or a personal computer, and more particularly, to a thermal printer having a detecting means for detecting whether or not an ink ribbon cassette is mounted, and Each time one line of printing is performed, the presence or absence of an ink ribbon cassette is detected, and a thermal transfer mode that prints on paper via the ink ribbon cassette and a thermal print mode that prints directly on thermal paper are selected according to the detection result. The present invention relates to a serial type thermal printer.

[0002]

2. Description of the Related Art As an example of a serial type thermal printer, a thermal printing mode in which printing is performed by pressing a recording head opposed to a platen against a platen with a sheet interposed therebetween, and a ribbon (ink ribbon) drawn out from a sheet and a ribbon cassette ) Can be selected from a thermal transfer printing mode in which printing is performed by pressing the recording head against a platen with the print head interposed therebetween.

FIG. 9 shows the control contents of a CPU in a printing operation of a conventional serial thermal printer. When there is a print execution command, this control program starts and the CPU
First, in step S1, the presence or absence (attachment / non-attachment) of an ink ribbon cassette (hereinafter, ribbon cassette) is determined based on a detection signal of a detection sensor. If the ribbon cassette is "yes", the process proceeds to step S2, where 1 is set in the thermal transfer printing mode.
Causes printing of lines to be executed.

Subsequently, in step S3, it is determined whether or not printing has been completed. If it is determined that printing has not been completed, the process returns to step S1 to perform printing on the next and subsequent lines. Rerun the process.

On the other hand, if it is determined in step S1 that the ribbon cassette is "absent", the process proceeds to step S4 in this case,
Here, printing for one line is performed in the thermal printing mode, and then it is determined in step S3 whether or not printing has been completed. That is, in this conventional example, the presence or absence of the ribbon cassette is detected every time printing of one line is performed, and the thermal transfer printing mode is selected when "Yes" and the thermal printing mode is selected when "No". .

[0006]

According to the above-described operation procedure, for example, after the printing of the nth line is performed in the thermal transfer printing mode, the printing of the next (n + 1) th line is performed in the thermal printing mode. I do. By the way, in the continuous printing operation of the serial thermal printer, the print mode is rarely changed during the printing of one page. Therefore, the CPU waits until the n-th line for the ribbon cassette "Yes".
It is extremely likely that the determination of the ribbon cassette “absent” from the (n + 1) th line onward is very likely due to erroneous detection of the detection sensor.

[0007] As a result of such an erroneous detection, if the printing of the (n + 1) th line and subsequent lines is to be performed in the thermal printing mode, as will be understood from the description of the mechanism of the thermal printer of the present invention described later, the ink ribbon is not wound up and printing becomes impossible. State.

On the other hand, when the detection result of the detection sensor is normal, not erroneous detection, up to the nth line is printed on plain paper in a thermal transfer printing mode via an ink ribbon.
The thermal printing mode should be performed on the thermal paper from the (n + 1) th line onward. However, the detection accuracy of the detection sensor is not reliable for the above-mentioned reason. May be determined. In this case, since there is no ink ribbon, printing is performed on plain paper in the thermal printing mode.
Normal printing cannot be performed.

As described above, in the above conventional example, there is a possibility that a normal printing operation may not be performed due to erroneous detection of the detection sensor.

An object of the present invention is to provide a thermal printer capable of always performing normal printing operation without being adversely affected by erroneous detection of the detecting means. I do.

[0011]

The thermal printer according to the present invention has a detecting means for detecting whether or not the ink ribbon cassette is mounted, and the detecting means detects whether the ink ribbon cassette has been mounted before starting printing.
A thermal transfer printing mode for detecting the presence or absence of the ink ribbon cassette, detecting the presence or absence of the ink ribbon cassette each time printing is performed on a sheet for one line, and performing printing on the sheet via the ink ribbon cassette according to the detection result; , in the thermal printer for performing the thermal printing mode for printing directly on the thermal paper selectively, the said detection means, thermal transfer printing
When the ink ribbon cassette at least once during the printing execution by mode detects that it is mounted, the middle print 1
The printing in the thermal transfer printing mode is executed until printing of the page is completed or a print stop command is given during printing, thereby achieving the above object. Further, the thermal printer according to the present invention, wherein the detecting means
Is increased during printing in the thermal printing mode.
Even if it is detected that a
Until printing of one page in the middle is completed or in the middle of printing
Printing in the thermal print mode until a character stop command is given
And the above purpose is
Achieved.

[0012]

In the above arrangement, n of the one-page prints are printed.
Assuming that the thermal transfer printing mode is performed up to the line, this case corresponds to the case where the ink ribbon cassette “present” is detected n times, that is, at least once, the ink ribbon cassette “present” . Until printing is completed
The thermal transfer printing mode is continuously performed until a print stop command is given during printing. Therefore, even if the detection unit makes a false detection, the print mode is not changed afterwards, so that the ink ribbon is not taken up by the ink ribbon cassette in the middle of printing, thereby causing a print failure state. Never do.

It is also assumed that it is determined that the n-th line is the thermal print mode with the ink ribbon "absent" and that the n + 1-th line is the thermal transfer print mode with the ink ribbon "presence" due to erroneous detection by the detecting means. in this case, since the ink ribbon at the time of printing of the (n + 1) th row does not actually exist, until one page of print in the middle of printing is finished or printing
Until a print stop command is given on the way, printing on the thermal paper is subsequently performed in the thermal printing mode. Therefore, also in this case, normal printing is performed, and there is no adverse effect due to erroneous detection by the detection unit.

[0014]

Embodiments of the present invention will be described below.

FIG. 1 shows a system configuration of a serial thermal printer. A carriage unit 3, which is reciprocally movable in a printing direction indicated by an arrow B and a return direction opposite to the printing direction indicated by an arrow B, is arranged opposite to a sheet feed roller 2 which conveys the sheet 1 upward by rotation in the direction of arrow A. The carriage unit 3 is equipped with a recording head 30 that prints print data on the paper 1, and moves the carriage unit 3 in the direction of arrow B so that one line of print data is printed on the paper 1. Has become. When printing of one line (one line) of data is completed, the carriage unit 3 is returned to the original position. Subsequently, when the paper 1 is fed by a predetermined amount by the paper feed roller 2, the carriage unit 3 is again moved in the arrow B direction. And the second line is printed.

To explain a little more, this serial thermal printer uses a thermal printing mode in which printing is performed by directly pressing the recording head 30 against the paper 1 when thermal paper is used as the paper 1, and a thermal printing mode in which the paper 1 is plain paper. A thermal transfer printing mode for printing on the paper 1 via a ribbon can be selected. When the thermal transfer printing mode is selected, the recording head 30 is moved from a ribbon cassette (not shown) to a ribbon cassette as shown in the illustrated example. 5 and pull out the ribbon 5 with the platen 4
Printing in the thermal transfer printing mode is performed by contacting the paper 1 passing between the recording head 30 and the recording head 30.

At this time, portions of the ribbon 5 located on both sides in the horizontal direction of the recording head 30 are held by guide plates 36, 36 erected from the carriage unit 3. The platen 40 is long in the moving direction of the carriage unit 3,
It is held by a platen holder 4.

Switching between the thermal printing mode and the thermal transfer printing mode is controlled by the CPU 6. That is, when it is confirmed from the detection signal from the ribbon detection switch 62 that the ribbon cassette is set in the printer main body, the operation mode is switched to the thermal transfer printing mode, and if it is determined that the ribbon cassette is not set, the thermal printing mode is executed. It has become.

Here, the detection signal from the ribbon detection switch 62 is given to the CPU 6 each time a printing operation for one line is performed, and each time the CPU 6 determines the printing mode and executes the corresponding printing mode. Note that C that controls the printing operation
Specific control contents of the PU 6 will be described later.

The CPU 6 also controls the movement of the carriage unit 3, the head up / down control of the recording head 30, the heating control of the recording head 30, and the paper feed roller 2.
Is performed. The drive control of the carriage unit 3 is performed by controlling the drive of the motor 32 via the carriage motor driver 63. To explain a bit now,
A pinion 33 that meshes with a pulley gear 34 is connected to an output shaft of the motor 32. When the motor 32 is driven in the normal or reverse direction, the pinion 33 is wound around the shaft of the pulley gear 34 and is connected to the carriage unit 3. The timing belt 35 of FIG. 3 moves around, whereby the carriage unit 3 reciprocates. The reciprocating movement of the carriage unit 3 is guided by a guide bar 37.

Head up / down control of the recording head 30 is performed by driving and controlling a motor 140 described later via an up / down motor driver 64. Here, head-up of the recording head 30 refers to a state in which the recording head 30 is separated from the surface of the platen 40 by a predetermined angle, and is selected during non-printing. On the other hand, head down refers to a state in which the recording head 30 is pressed against the surface of the platen 40 with a predetermined pressure across the sheet 1 (or the sheet 1 and the ribbon 5).
Selected when printing.

The heating control of the recording head 30 is performed via a head driver 65, and the driving control of the paper feed roller 2 is performed via a paper feed driver 66.

When the thermal printing mode or the thermal transfer printing mode is selected, the CPU 6 executes these printing modes in accordance with the control program stored in the ROM 60, and stores the obtained control data and the like in the RAM 61 at that time. Each of the above-described controls is performed in accordance with the data stored in the RAM 61.

Next, the details of the carriage unit 3 will be described with reference to FIGS. As shown in FIG.
The recording head 30 is supported by a head holder 102 which is rotatably supported by a horizontal support pin 101. The head up position shown in FIG. 3 and the head down position shown in FIG. (Rotation) is possible.

In the switching operation of the recording head 30, that is, the head up / down operation, a head holding member 110 having a fan shape in plan view, a cam follower 120 having a parallelogram shape in plan view, and a cam groove 131 are formed on the upper surface side. Cam gear 130 and a motor 1 for rotationally driving the cam gear 130
Head up / down mechanism 100 composed of 40 and the like
Done by Hereinafter, the configuration of each unit will be specifically described.

Head holding member 110 and cam follower 12
0 is linked so as to be interlockable. That is, the portion of the head holding member 110 corresponding to the main part of the fan and the cam follower 1
20 are connected to each other at a corresponding position by a vertical pin 111, and at one end of an arc-shaped outer edge of the head pressing member 110, a connecting pin 112 formed to protrude upward is connected to a connecting hole of the cam follower 120. 121, and one end of a spring 122 composed of a coil spring is locked and connected to the connection pin 112, and the other end is locked to one end surface of a cam follower 120 located on the other end side of the outer edge of the head holding member 110. We are connecting the two.
The connection hole 121 is a long hole as can be seen from FIG.

In addition, a torsion coil spring is provided in the rotation area of the head holding member 110 which is rotatable around the vertical pin 111.
A spring 113 that is constantly biased toward the zero side is provided. Specifically, the spring 114 is attached to the vertical support pin 115 by fitting the coil portion to the vertical support pin 115.

A cam follower pin 123 is formed on a portion of the cam follower 120 opposite to the spring engagement position by caulking. The cam follower pin 123 is engaged with a cam groove 131 formed in the cam gear 130. The cam groove 131 is formed in a spiral shape around the rotation center O of the cam gear 130, as shown in FIGS. The cam radius r of the cam groove 131 changes as shown in FIG.
The head up / down operation of the recording head 30 is performed by the change of the engagement position with the head, and the details thereof will be described later.

The cam gear 130 meshes with a pinion 141 connected to the output shaft of the motor 140. Therefore, when the motor 140 rotates in the CW direction and the CCW direction, the cam gear 130 rotates in the CCW direction and the CW direction.

In addition to the above configuration, this serial type thermal printer has a switching mechanism 1 for selectively rotating and not rotating the ribbon take-up reel 159 of the ribbon cassette.
60 will be equipped. The rotation of the ribbon take-up reel 159 is performed to take up the used ribbon 5 in the thermal transfer printing mode. Hereinafter, the switching mechanism 160 will be described in detail.

As shown in FIG. 2, a cam groove 132 is formed on the lower surface of the cam gear 130 so that an engaging projection 151 formed on one end of the clutch lever 150 is engaged.
As shown in FIGS. 3 to 6, the clutch lever 150 has a shape in which radial projections are formed in three directions from a central portion, and is rotatable around a rotation center axis 154 at the central portion.
The cam groove 132 is provided for performing a switching operation of the clutch lever 150. That is, as shown in FIG. 2, a ribbon take-up gear 152 is connected to a rotation center shaft 154 of the clutch lever 150,
52 is always meshed with the switching gear 153 connected to the other convex portion of the clutch lever 150. Therefore, the cam groove 13
When the clutch mechanism 150 is rotated in the CW direction or the CCW direction about the rotation center axis 154 via the cam gear 130 by the cam mechanism configured by the camshaft 2 and the engagement protrusion 151,
A position where the switching gear 153 meshes with the belt pulley gear 155 for winding the ribbon (see FIG. 4), and a position where the meshing state with the belt pulley gear 155 is released (see FIG. 3).
Can be switched to

Belt pulley gear 15 for winding ribbon
Reference numeral 5 is mounted on the carriage unit 3, connects the belt pulley gear 155 and the toothed pulley 156, and is supported by a connecting shaft 157 rotatably supported by the carriage unit 3. The toothed pulley portion 156 has the both ends fixed to the left and right sides of the chassis of the printer body, that is, the timing belt 1 for winding the ribbon in a fixed state.
58. Accordingly, when the carriage unit 3 moves in the direction of arrow B for printing, the belt pulley gear 155 moves integrally with the belt pulley gear 155 in the direction of arrow B and rotates in the CCW direction as shown in FIG.

The switching gear 153 is a belt pulley gear 155
When the toothed pulley portion 156 rotates in the CCW direction while meshing with the belt pulley gear 155, the belt pulley gear 155 also rotates in the CCW direction. Rotate in the direction. A ribbon take-up reel 159 of a ribbon cassette is coaxially supported by the ribbon take-up gear 152. Accordingly, the ribbon take-up reel 159 rotates integrally with the ribbon take-up gear 152, whereby the portion of the ribbon 5 that has been subjected to printing in the thermal transfer printing mode is taken up by the ribbon take-up reel 159 having a predetermined length.

Next, details of the head up / down operation of the recording head 30 will be described. As shown in FIG. 2, in the present invention, the recording head 30 has a head-up angle θ
₁ and θ ₂ . Here, θ ₁ indicates the head-up angle of the recording head 30 in the thermal transfer printing mode, and θ ₂ indicates the head-up angle of the recording head 30 in the thermal printing mode.

When the recording head 30 is moved up by the head-up angle θ ₁ , a ground plate (not shown) comes into contact with the back surface of the recording head 30 to remove static electricity generated in the thermal transfer printing mode. I have.

The setting of the head-up angles θ ₁ and θ ₂ and the head-down operation are set by the positional relationship between the cam follower pin 123 of the cam follower 120 and the cam groove 131 of the cam gear 130. That is, when a ribbon detection signal is input to the CPU 6 from the ribbon detection switch 62, the CPU 6 determines that the ribbon cassette is set in the printer and the thermal transfer printing mode is selected, and performs initial processing of the printer. When the initial process is performed and the cam gear 130 is rotated by a predetermined angle, the cam follower 120 is moved to the position shown in FIG. 3 by the cam mechanism including the cam follower pin 123 and the cam groove 131.

FIG. 7A shows a cam diagram of this cam mechanism. The initial point a is a diagram in which the recording head 30 is set in a head-up state (head-up angle = θ ₁ ) in the thermal transfer printing mode. This corresponds to the state shown in FIG. Specifically, it corresponds to one end of the cam groove 131.

As is clear from FIG. 7A and FIG.
At this initial point a, the cam follower pin 12
3 and the distance r ₁ between the rotation center O is the largest.

As shown in FIG. 7B, when the cam follower pin 123 is located at the initial point a, the switching gear 153 and the belt pulley gear 155 are in a disengaged state.

When the motor 140 is driven from the state shown in FIG. 3 to rotate the cam gear 130 by a predetermined angle in the CW direction,
Guided by the cam groove 131, the cam follower pin 123
Moves to the position shown in FIG. In the cam diagram shown in FIG. 7A, the head moves to the head pressure point c. At the head pressure point c, printing in the thermal transfer printing mode is performed.

In the position shown in FIG. 4, the cam follower pin 1
23 is close to the rotation center O, the cam follower 1
Numeral 20 rotates about the vertical pin 111 as a fulcrum in the CW direction as a whole. With this rotation operation, the head holding member 11
Spring 122 for interlocking cam follower 120 with 0
Is pulled, and the spring 122 causes the connecting pin 112, that is, the head pressing member 110
Is pulled toward the platen 40 with the vertical pin 111 as a fulcrum. As a result, the head pressing member 110 presses the recording head 30, and the recording head 30 is
Is pivoted toward the platen 40 with. As a result, the recording head 30 comes into contact with the platen 40. That is, the head down operation of the recording head 30 is performed.
At this time, the recording head 30 is pressed against the platen 40 with a predetermined pressing force by the urging force of the spring 113 pressing the head pressing member 110. Thus, printing in the thermal transfer printing mode is performed. When the operation opposite to the above is performed from the state shown in FIG. 4, the head-up operation of the recording head 30 is performed.

As shown in FIG. 7B, when the cam follower pin 123 is located at the head pressure point c, the switching gear 153 and the belt pulley gear 155 are switched to the meshing state.

On the other hand, when the ribbon cassette detection signal is not input from the ribbon detection switch 62, the CPU 6 determines that the print mode is the thermal print mode and causes the printer to perform an initial process in the thermal transfer print mode. When this initial processing is performed, the motor 140
0 to the position shown in FIG.
Are located at the other end of the cam groove 131 shown in FIG. This position corresponds to the initial point b in the cam diagram shown in FIG. 7A, and the recording head 30 is in the head-up state.

As is clear from FIG. 7A, at the initial point b, the cam follower pin 123 and the rotation center O
Is r ₂ , and between r ₂ and r ₁ , r ₂ <r ₁
Is established. Therefore, the amount of tilt of the cam follower 120 in the CW direction at the initial point b is larger than the amount of tilt at the initial point a. Therefore, the head-up angle theta ₂ of the recording head 30 in the thermal printing mode is smaller than the head-up angle theta ₂ in the thermal transfer printing mode. That is, the relationship of θ ₁ > θ ₂ is established.

When the motor 140 is driven from the state shown in FIG. 5 to rotate the cam gear 130 by a predetermined angle in the CCW direction, the cam follower pin 123 is guided by the cam groove 131.
Moves to the state shown in FIG. 6, that is, the head pressure point d in the cam diagram shown in FIG. 7A. At this time, the cam follower 120 tilts by a predetermined amount in the CW direction about the vertical pin 111 as a fulcrum in the same manner as described above, and accordingly, the head down operation of the recording head 30 is performed, and the thermal printing is performed at this head pressure point d. Printing in the mode is performed. As shown in FIG. 7 (b), at the head pressure point d, the switching gear 153 and the belt pulley gear 155 are in the state of disengagement.

As described above, the cam mechanism for causing the recording head 30 to perform the head up / down operation is provided with two initial points, and the two headed up angles θ ₁ , θ 2 different in the thermal printing mode and the thermal transfer printing mode.
_{When 2} (θ ₁ > θ ₂ ) is set, the time required for the head-up operation and head-down operation of the recording head 30 in the thermal print mode can be shorter than that in the thermal transfer print mode, so that the print time in the thermal print mode is reduced. This is convenient for achieving high-speed printing of the printer.

As shown in FIG. 7 (a), when a cam mechanism having two initial points and two head pressure points is used as described above, one initial point a (or The recording head 30 is moved from b) to one head pressure point c (or d).
Of the motor 14 during the switching operation.
A large load fluctuation does not occur on the output shaft 0, and there is no need to use a large motor 140 having a driving torque enough to cope with the load fluctuation. Further, even if the switching operation is performed at a high speed, no loud noise is generated.

For this reason, according to the present invention,
Since the switching operation of the recording head 30 can be performed at a high speed by the small motor 140, a serial thermal printer that can perform high-speed printing at low cost can be realized.

When the cam groove 131 is formed in a spiral shape as described above, and one end of the cam groove 131 is set at the initial point a and the other end is set at the initial point b, the cam radii are different. Since two initial points can be secured, the total rotation angle β ₃ (see FIG. 7) is 360 °
Even with the above, a small cam gear 130 can be realized as shown in FIGS. Therefore, also in this respect, the size of the device can be reduced.

In the case where the above-described ribbon winding mechanism is provided, as described in the above-mentioned prior art, for example, in the printing operation for one continuous line, up to the n-th line is performed. In the “Yes” thermal transfer printing mode, n
When the + 1st line is the thermal print mode of the ribbon “absent”, that is, when the detection result of the ribbon detection switch 62 changes from the ribbon “present” to the ribbon “absent” when printing the (n + 1) th line, In such a case, the CPU 6 erroneously determines that the thermal print mode is selected as the print mode.
For this reason, the ribbon 5 is not taken up on the ribbon take-up reel 159 irrespective of the actual thermal transfer printing mode.

In order to eliminate the problem caused by the erroneous detection of the ribbon detection switch 62, the thermal printer of the present invention performs the printing operation shown in FIG. That is, when a print execution command is given and the program in the ROM 60 is started, the CPU 6 first determines “present” or “absent” of the ribbon cassette based on the detection result of the ribbon detection switch 62 in step S10, and , The process proceeds to step S11, where one line of printing is performed in the thermal printing mode. Subsequently, in step S12, it is determined whether or not printing has been completed.
It returns to 10 and prints the next line. Then, when the printing is completed, this processing is completed.

Here, the printing end determining operation shown in step S12 is to determine the printing end when the printing operation is actually ended and when a print stop command is given to the CPU 6 during printing. I do.

On the other hand, if it is determined in step S10 that the ribbon cassette is "present", the process proceeds to step S13, where the thermal transfer printing mode is subsequently executed until printing is completed. That is, in the thermal printer according to the present invention, the ribbon cassette “yes” even once during the printing operation.
Is determined, the thermal transfer printing mode is continued until the printing is completed.

According to the thermal printer of the present invention having such a configuration, even if the ribbon detection switch 62 makes an erroneous detection during the execution of the thermal transfer printing mode, the printing mode is not changed afterwards. During the printing, the ribbon 5 is not taken up by the ribbon cassette, so that the printing failure cannot be caused.

Further, for example, up to the n-th line is a thermal print mode in which the ink ribbon is “absent”, and the ribbon detection switch 6
When the n + 1 th row is determined as the thermal transfer printing mode of the ribbon cassette "Yes" by 2 false positives, since the ribbon cassette when performing printing of the (n + 1) th row does not actually exist, of course the print 1 Until the printing of the page is completed or
Until a print stop command is given during printing, printing on the thermal paper is subsequently performed in the thermal printing mode. Therefore, also in this case, normal printing is performed, and there is no adverse effect due to erroneous detection of the ribbon detection switch 62.

When the printing of one page is completed, the print mode may be switched.
In the present invention, the ribbon cassette “Yes” during printing
Is changed to “no” from the ribbon cassette, the thermal transfer printing mode is continued until printing of at least one page is completed.

In the above embodiment, the case where the present invention is applied to an embodiment in which a head pressure point is made different in both printing modes in a serial thermal printer in which a thermal transfer printing mode and a thermal printing mode can be selected. However, for example, in the thermal transfer printing mode, the present invention can be similarly applied to other embodiments in which printing is performed by changing the head pressure points for plain paper and recommended paper.

[0058]

According to the above-described thermal printer of the present invention, if the presence of the ink ribbon cassette is detected at least once during printing in the thermal transfer printing mode , the printing of one page in the middle of printing is completed or Since the printing is performed in the thermal transfer printing mode via the ink ribbon until a print stop command is given, a print disabled state occurs due to the ink ribbon not being taken up by the ink ribbon cassette during printing. Nothing.

Further, execution of printing in the thermal printing mode
In thermal printing mode until the n-th row of the ink ribbon "No" in, even when the (n + 1) th row by the erroneous detection detecting means is determined to be the thermal transfer print mode of the ink ribbon "Yes", the print Until the printing of one page in the middle is completed,
The printing on the thermal paper is subsequently performed in the thermal printing mode until a print stop command is given during printing . Therefore, even in this case, normal printing is performed,
There is no adverse effect due to erroneous detection of the detection means.

As described above, according to the thermal printer of the present invention, the adverse effects caused by the erroneous detection of the detecting means can be reliably eliminated, so that a normal printing operation can be always performed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a system configuration of a serial type thermal printer of the present invention.

FIG. 2 is a side view illustrating a configuration of a carriage unit.

FIG. 3 is a plan view of a carriage unit showing a head-up state of a recording head in a thermal transfer printing mode via a ribbon.

FIG. 4 is a plan view of the carriage unit showing a head down state of the recording head in a thermal transfer printing mode via a ribbon.

FIG. 5 is a plan view of the carriage unit showing a head-up state of the recording head in a thermal print mode.

FIG. 6 is a plan view of the carriage unit showing a head down state of the recording head in a thermal print mode.

FIG. 7 is a drawing comparing a cam diagram of a cam mechanism for head up / down and a cam diagram of a cam mechanism for switching a clutch lever.

FIG. 8 is a flowchart showing control contents of a CPU for controlling a printing operation of the thermal printer of the present invention.

FIG. 9 is a flowchart showing control contents of a CPU in a printing operation of a conventional example.

[Explanation of symbols]

 Reference Signs List 1 paper 2 paper feed roller 3 carriage unit 5 ribbon 6 CPU 30 recording head 32 motor 35 timing belt 40 platen 62 ribbon detection switch 100 head up / down mechanism 110 head pressing member 111 vertical pin 113 spring 115 vertical support pin 120 cam follower 122 spring 123 Cam follower pin 130 Cam gear 131 Cam groove 132 Cam groove 140 Motor 150 Clutch lever 151 Engagement projection 152 Ribbon winding gear 153 Switching gear 155 Belt pulley gear 156 Toothed pulley 158 Timing belt 160 Switching mechanism

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-45075 (JP, A) JP-A 1-171647 (JP, U) JP-A-61-128036 (JP, U) (58) Investigation Field (Int.Cl. ⁶ , DB name) B41J 2/32-2/325 B41J 35/28 B41J 35/36

Claims (2)

(57) [Claims] A detecting means for detecting whether or not the ink ribbon cassette has been mounted, wherein the detecting means detects whether or not printing has been performed;
Before the start, the presence or absence of the ink ribbon cassette is detected, and thereafter , every time printing is performed on a sheet of paper for one line, the presence or absence of the ink ribbon cassette is detected, and through the ink ribbon cassette according to the detection result. In a thermal printer for selectively performing a thermal transfer printing mode for printing on paper and a thermal printing mode for directly printing on thermal paper, the detecting means may detect that one of the thermal printing modes is in effect during printing in the thermal transfer printing mode.
A thermal printer that executes printing in the thermal transfer printing mode until the printing of one page in the middle of printing is completed or a print stop command is given in the middle of printing when it is detected that the ink ribbon cassette is mounted. 2. An ink ribbon cassette is mounted.
Detection means for detecting whether or not printing has been performed by the detection means.
Before starting, the presence or absence of the ink ribbon cassette is detected.
Each time one line of printing is performed on paper, the ink ribbon cover
The presence or absence of the set is detected, and the ink
Thermal transfer printing mode for printing on paper via a cassette
And thermal printing mode for printing directly on thermal paper
Thermal printer The detection unit detects that the printing is being performed in the thermal printing mode.
Detects that the ink ribbon cassette is installed
Or until printing of one page during printing is completed or
Until a print stop command is given during printing, the thermal printing mode
A thermal printer that prints code.