JP2001121727A - Thermal transfer printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To print with a high quality at all times irrespective of a distance from a paper leading end to a printing start position. SOLUTION: When a required time from a time when the leading end of the paper transferred along a transfer path passes from the upstream side to the downstream side of a thermal head to the printing start position is shorter than a predetermined time, the thermal transfer printer is controlled so that the thermal head is brought in contact with a platen roller and an ink ribbon is started to travel at a time point earlier than when the predetermined time passes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a thermal transfer printer for performing printing by a thermal transfer method via an ink ribbon by a thermal head.

[0002]

2. Description of the Related Art As a conventional thermal transfer printer, four thermal heads corresponding to four colors of yellow, magenta, cyan, and black are sequentially arranged along a paper transporting path, and each thermal head is disposed across the transporting path. It is known that a platen roller is disposed at a position facing the head, and each thermal head is brought into contact with the platen roller via an ink ribbon of each color, and the ink ribbon is run to perform color printing on paper. .

In order to save the ink ribbon, this type of thermal transfer printer is provided with a mechanism for bringing each thermal head into contact with and separating from the platen roller via the ink ribbon. And the ink ribbon was running.

[0004] However, if the thermal head is brought into contact with the platen roller and the ink ribbon is run at the same time as printing is started, the initial printing quality is significantly reduced.
Therefore, conventionally, the thermal head is brought into contact with the platen roller by a predetermined time Ta (for example, 120 ms) earlier than the printing start time, and the ink ribbon is caused to travel so that high quality printing can be performed from the beginning. Was.

[0005]

However, the conventional thermal transfer printer, in which the thermal head is brought into contact with the platen roller and the ink ribbon is controlled to run by a predetermined time Ta earlier than the printing start time, has not been solved yet. The following issues had to be raised. In other words, when the leading edge of the sheet conveyed along the conveyance path is at or near the contact position between the thermal head and the platen roller, the traveling of the ink ribbon is started simultaneously with the contact of the thermal head with the platen roller. However, the impact that the leading edge of the paper is pressed by the thermal head and the transient unstable running of the ink ribbon at the beginning of running will cause braking on the paper transport, distorting the paper and displacing the print position or blurring the print. In some cases, desired printing quality cannot be obtained.

When the leading end of the sheet is at or near the contact position between the thermal head and the platen roller, an event that the thermal head contacts the platen roller occurs from the leading end of the sheet to the printing start position. Related to the distance. For example, if the paper conveyance speed is set to 100 mm / s and the thermal head is brought into contact with the platen roller 120 ms earlier than the printing start time, the time from when the thermal head comes into contact with the platen roller until printing starts is started. The paper transport distance is 12 mm (= 100 mm /
s × 0.12 s). That is, when the distance from the leading end of the sheet to the printing start position is near 12 mm, the leading end of the sheet is located at or near the contact position when the thermal head contacts the platen roller. .

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a thermal transfer printer which can always perform high-quality printing regardless of the distance from the leading edge of a sheet to the printing start position. Is what you do.

[0008]

According to the first aspect of the present invention, a thermal head is disposed along a paper transport path, and a platen roller is disposed at a position facing the thermal head across the transport path. And a mechanism for contacting and separating the thermal head from the platen roller via the ink ribbon. When printing is started, the thermal head is brought into contact with the platen roller a predetermined time earlier than the printing start time, and the ink ribbon is When the required time from the time when the leading edge of the paper conveyed along the conveyance path passes from the upstream side to the downstream side of the thermal head to the printing start time is shorter than a predetermined time, The thermal head is brought into contact with the platen roller earlier than the predetermined time and the ink ribbon starts running. It is obtained by sea urchin control.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In this embodiment, the present invention is applied to a color thermal printer that performs color printing by superimposing four colors of yellow, magenta, cyan, and black.

FIG. 1 shows the structure of a color thermal printer to which the present invention is applied. A thermal head 1 for Y (yellow), a thermal head 2 for M (magenta), a thermal head 3 for C (cyan), and K ( Black) thermal heads 4 are arranged in order along the paper transport path 5. Each of the thermal heads 1, 2, 3, 4,
Platen rollers 6, 7, and
8, 9 are provided.

Each of the thermal heads 1, 2, 3, and 4 has a plurality of heating resistors arranged in parallel on an end face thereof.
Ribbon magazines 10, 11, 12, and 13 are detachably set. These ribbon magazines 10, 11, 1
Reference numerals 2, 13 denote feed-side rollers 10a, 11a, 12a, 1
3a and take-up rollers 10b, 11b, 12b, 13
b, the unused ink ribbons 10c, 11c, 12c, 13c wound around the feed rollers 10a, 11a, 12a, 13a are fed to the thermal heads 1, 2, 3, 4 by motor driving (not shown). Ribbons 10c, 11c, 1 having passed through thermal heads 1, 2, 3, 4
2c and 13c are taken up by the winding rollers 10b, 11b and 12
b, 13b. The color of the ink ribbon 10c is yellow, the color of the ink ribbon 11c is magenta, the color of the ink ribbon 12c is cyan, and the color of the ink ribbon 13c is black.

One end of the transport path 5 is a sheet supply port 5a, and the other end is a sheet discharge port 5b. On the side of the paper supply port 5a, there are provided a pair of paper transport rollers 14 and 15, which are relocated across the transport, a sensor 16 for detecting the leading edge of the paper, a sensor 17 for detecting the end of the paper, and a paper holder 18. . A paper (continuous roll paper) 19 is wound around the paper holder 18.
The conveyance path 5 is held by the nip conveyance of the paper conveyance rollers 14 and 15.
The paper is conveyed upward toward the paper discharge port 5b.

On the other hand, the thermal heads 1, 2, 3, 4
The ink ribbons 10c, 11c,
Platen rollers 6, 7, 8, 9 via 12c, 13c
It is configured to come into contact with and separate from. FIG. 2 shows a mechanism for performing the contact and separation (only the mechanism for the thermal head 1).

As shown in FIG.
4) is vertically slidably held between the guide plates 21 and 22. The guide plates 21 and 22 are supported by side frames 25 and 26 of the printer body via guide pins 23 and 24. The platen roller 6 (to 9) is
7 and 28, the side frame 25 of the printer body,
26 is rotatably supported.

A head frame 31 is provided above the thermal head 1 (.about.4), and an intermediate portion of an arm 33 is rotatably supported by a shaft 32 projecting from the head frame 31. One end of the arm 33 is engaged with the movable pin 34a of the solenoid 34, and the other end is bent toward the thermal head 1 (.about.4) to support the head support shaft 35 from below. A head fixing member 36 is pivotally supported by the head support shaft 35, and the thermal heads 1 to 4 are fixed to the head fixing member 36. A pressing member 37 is in contact with the upper part of the head support shaft 35. The pressing member 37 is connected to a spring 38, and the pressing member 37 and the spring 38 apply a biasing force downward (to the platen roller) with respect to the thermal head 1 (to 4). I have.

That is, when the solenoid 34 is deenergized, the biasing force of the pressing member 37 and the spring 38 causes the thermal head 1 (.about.4) to contact the platen roller 6 (.about.9) via the ink ribbon 10c (.about.13c). Abut When the solenoid 34 is energized, the movable pin 34a is lowered, and accordingly, one end of the arm 33 is lowered and the other end of the arm 33 is raised. Due to this rise, the thermal head 1 (~
4) is bored by the biasing force of the pressing member 37 and the spring 38, and is separated from the platen roller 6 (６9).

FIG. 3 is a block diagram showing a main part control circuit of the color thermal printer. This color thermal printer has a CPU (Central Processing) as a main control part.
Unit) 51 is provided. Also, a ROM in which program data of the processing performed by the CPU 51 is stored in advance.
(Read Only Memory) 52, RAM in which various memory areas such as a print buffer for expanding print data are formed
(Random Access Memory) 53, various sensors such as a sensor 16 for detecting the leading edge of the paper, a sensor 17 for detecting the end of the paper, a driving mechanism for the paper conveying rollers 14, 15, a driving mechanism for each of the platen rollers 6 to 9, and an ink ribbon 10c. ~ 13
A gate array 55 for an engine, which controls an engine unit 54 including various driving devices such as a feed mechanism for C, a driving mechanism for a solenoid 34 corresponding to each of the thermal heads 1 to 4, and a display for controlling a display / operation unit 56.・ Operation controller 57, ISA with host computer etc. via line
Reception FIFO (First In First
OUT) 58 and a transmission FIFO 59, and are connected to the CPU 51 via the system bus 60.

Further, a Y head controller 61 for controlling the driving of the Y thermal head 1, an M head controller 62 for controlling the driving of the M thermal head 2, and a C head for controlling the driving of the C thermal head 3 are provided. A controller 63 and a K head controller 64 for controlling the driving of the K thermal head 4 are connected to the CPU 51 via a system bus 60.

Further, a Y buffer 65 for supplying print data to the Y head controller 61 and an M buffer 6 for supplying print data to the M head controller 62
6. The C buffer 67 for supplying print data to the C head controller 67 and the K buffer 68 for supplying print data to the K head controller 68 are connected to the CPU 51 via the system bus 60.

The main function of the CPU 51 is to execute the control processing shown in the flowcharts of FIGS. 4 and 5. Until the control process is started, the solenoids 34 corresponding to the respective thermal heads 1 to 4 are energized,
(〜4) are in a state of being separated from the platen roller 6 (〜9). Further, the leading end of the sheet 19 is located upstream of the sheet leading end detection sensor 16 in the sheet transport direction.

When print data for each of the thermal heads 1 to 4 is transferred from the host computer, the CPU 51 starts this control processing. First, the print start position is determined from the form of the received print data. So ST
(Step 1) The distance L from the leading edge of the sheet to the print start position is calculated based on the print data. Further, the thermal heads 1 (to
The distance L1 to 4) is known in advance and the paper 19
Since the transport speed V is constant, the required time T from when the leading edge of the sheet 19 is detected by the sheet leading edge detection sensor 16 to when printing is started by each of the thermal heads 1 to 4 (ST2).
1 (T1 = (L + L1) / V) is calculated.

Next, in ST3, it is checked whether or not the distance L from the leading edge of the sheet to the printing start position is longer than a predetermined value. Here, if the distance L from the leading edge of the sheet to the printing start position is longer than a predetermined value, the drive mechanism of the sheet transport rollers 14 and 15 is activated in step ST4 and the sheet 1 is started.
9 is conveyed toward the paper discharge port 5b.

Next, in step ST5, the control waits for the sheet leading edge detecting sensor 16 to detect the leading edge of the sheet 19. When the sheet leading edge detection sensor 16 detects the leading edge of the sheet 19, the timer operation of a timer counter built in the CPU 51 is started in ST6.

In this state, the process waits at ST7 until the timer counter measures a time obtained by subtracting a first predetermined time Ta (Ta <T1) from the required time T1. Then, when the timer counter has counted (T1-Ta) time, the energizing of each solenoid 34 is released and the thermal head 1 (.about.4) is moved to the platen roller 6 via the ink ribbon 10c (.about.13c) in ST8. (~ 9)
Contact. At the same time, in ST9, the feed mechanism of the ink ribbon 10c (起動 13c) is activated to run the ink ribbon 10c (〜13c). Then, ST1
It is set to 0, and waits until the timer counter measures the required time T1. Then, when the timer counter has counted the required time T1, the thermal head 1 (.about.4) is driven to print the print data in ST11.

On the other hand, when the distance L from the leading edge of the sheet to the printing start position is equal to or less than the predetermined value in ST3, as described above, the thermal head
Since the distance L1 to (−4) is known in advance and the transport speed V of the paper 19 is constant, the leading edge of the paper 19 is detected by the leading edge detection sensor 16 in ST12, and then the thermal head 1 Required time T2 (T2 = L1 / V) for passing from (4) to the downstream side from the upstream side
Is calculated. Thereafter, in ST13, the drive mechanism of the paper transport rollers 14, 15 is activated to transport the paper 19 toward the paper outlet 5b.

Next, in step ST14, the process waits for the sheet leading edge detecting sensor 16 to detect the leading edge of the sheet 19. When the leading edge detection sensor 16 detects the leading edge of the sheet 19, the timer operation of the timer counter built in the CPU 51 is started as ST15.

In this state, as ST16, the timer counter starts counting from the required time T2 to the first predetermined time Ta (T
It waits until the time obtained by subtracting a <T2 <T1) is counted. When the timer counter has counted (T2−Ta) time, in step ST8, the energizing of each solenoid 34 is released, and the thermal head 1 (４4) is moved to the ink ribbon 10.
The platen roller 6 (.about.9) is brought into contact with the platen roller 6 (.about.9) via c (.about.13c). At the same time, as ST18, the ink ribbon 1
The feed mechanism of 0c (１３13c) is activated to run the ink ribbon 10c (〜13c). After that, ST10
And waits until the timer counter measures the required time T1. When the timer counter has counted the required time T1, the thermal head 1 (.about.4) is driven to print the print data.

In this way, printing of print data is performed,
When the printing ends at T19, the CPU 51 proceeds to S19.
As T20, the timer counter is restarted.
When the timer counter measures a second predetermined time Tb set in advance as ST21, ST22
To energize each solenoid 34 to
(〜4) is separated from the platen roller 6 (〜9).
At the same time, as ST23, the ink ribbon 10c (~ 1
3c) is stopped, and the ink ribbon 10c (~
13c) is stopped. Further, in ST24, the drive mechanism of the sheet transport rollers 14, 15 is stopped to
Stop transporting Thus, the current control processing ends.

During printing of print data, ST
When the end-of-paper detection sensor 17 detects the end of the paper 19 as 25, and before the timer counter measures the second predetermined time Tb, the end-of-paper detection sensor 17 detects the end of the paper 19 as ST26. If detected,
In step ST27, each of the solenoids 34 is energized to separate the thermal head 1 (.about.4) from the platen roller 6 (.about.9). At the same time, as ST28, the ink ribbon 10c
The feed mechanism of (〜13c) is stopped and the ink ribbon 10
The running of c (~ 13c) is stopped. Further, in ST29, the drive mechanism of the paper transport rollers 14, 15 is stopped to stop the transport of the paper 19. After that, if the display / operation unit 56 reports an out-of-paper error in ST30, the current control processing ends.

In the present embodiment configured as described above, the transport speed of the sheet 19 is set to 100 mm / s. Further, the first predetermined time Ta set in advance is set to 120 ms. Further, the distance L from the leading edge of the paper to the printing start position is L.
Is 15 mm.

Now, assuming that print data having a distance L from the leading edge of the sheet to the printing start position longer than a predetermined value of 15 mm is received, as shown in FIG. Until the required time T1 until the printing starts, the thermal head 1 (.about.4) moves the ink ribbon 10c at a point earlier than the printing start time by a first predetermined time Ta (= 120 ms). (~ 13c) via the platen roller 6 (~ 9)
Abut. At the same time, the ink ribbon 10c
(~ 13c) starts running.

In this case, the thermal head 1 (to 4)
At the point when the sheet 19 contacts the platen rollers 6 (６9), that is, at a point 120 ms before the printing start time, the leading end of the paper 19 is
It has already been transported 3 mm or more downstream from the contact position with (.about.9). When the leading end of the sheet has passed 3 mm or more, even if the thermal head 1 (.about.4) receives an impact or the ink ribbon 10c (.about.13c) starts running, the sheet 19 will not move.
Is not distorted. Therefore, the ink ribbon 10c
High print quality can be ensured while saving (〜13c).

On the other hand, when print data having a distance L from the leading edge of the sheet to the printing start position of 15 mm or less is received, the leading edge of the sheet is detected by the leading edge sensor 16 as shown in FIG. From the upstream side to the downstream side of the thermal head 1 (.about.4) until a time T2 required for the leading edge of the paper to pass from the upstream side to the downstream side of the thermal head 1 (.about.4) elapses. At a point earlier by a first predetermined time Ta (= 120 ms) than the point at which the ink ribbon 1 passes through the ink ribbon 1.
The platen roller 6 contacts the platen roller 6 (to 9) through 0c (to 13c). At the same time, the ink ribbon 10c (~
13c) starts running.

Therefore, the leading end of the paper is
At the point of time when the thermal head 1 (.about.4) passes from the upstream side to the downstream side of (.about.4), the ink ribbon 10c (.about.1)
3c), the ink ribbon 10c (.about.13c) is running stably, and the leading end of the sheet is the thermal head 1 (.about.4) and the platen roller 6 (.about.9). To 9) smoothly,
The paper 19 is not distorted. Therefore, high printing quality can be ensured.

In the above-described embodiment, the paper 19 is a continuous roll paper. However, the present invention can be applied to a thermal transfer printer for printing on a cut sheet.

In the above embodiment, when printing print data in which the distance L from the leading edge of the sheet to the printing start position is shorter than a predetermined value, the leading edge of the sheet is
The thermal head 1 (.about.4) is moved via the ink ribbon 10c (.about.13c) to the platen roller 6 at a time earlier by a first predetermined time Ta than the time when the paper passes from the upstream side to the downstream side of (.about.4). (~ 9), and the running of the ink ribbon 10c (~ 13c) was started.
The leading edge of the paper is the thermal head 1 based on the printing start time.
The same operation as that of the present invention can be obtained by calculating the time from (4) passing from the upstream side to the downstream side until the start of printing, and setting a time longer than that time as the first reference time. The effect can be achieved.

[0037]

As described in detail above, according to the present invention,
It is possible to provide a thermal transfer printer that can always perform high-quality printing regardless of the length of the distance from the leading edge of the sheet to the printing start position.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a configuration of a mechanism for contacting and separating the thermal head according to the embodiment.

FIG. 3 is a block diagram showing a main part control circuit configuration of the embodiment.

FIG. 4 is a flowchart showing the first half of main control processing of the CPU according to the embodiment;

FIG. 5 is a flowchart showing a latter half of main control processing of the CPU according to the embodiment;

FIG. 6 is a timing chart for explaining the operation of the embodiment when the distance from the leading edge of the sheet to the printing start position is longer than a predetermined value.

FIG. 7 is a timing chart for explaining the operation of the embodiment when the distance from the leading edge of the sheet to the print start position is shorter than a predetermined value.

[Explanation of symbols]

 1, 2, 3, 4 ... thermal head 5 ... transport path 6, 7, 8, 9 ... platen roller 10, 11, 12, 13 ... ribbon magazine 10c, 11c, 12c, 13c ... ink ribbon 16 ... paper edge detection Sensor 17: End-of-paper detection sensor 19: Paper 34: Solenoid 51: CPU

Claims (1)

[Claims] 1. A thermal head is disposed along a paper transport path, a platen roller is disposed at a position facing the thermal head across the transport path, and the thermal head is connected via an ink ribbon. Has a mechanism to contact and separate from the platen roller, at the start of printing,
In a thermal transfer printer in which the thermal head is brought into contact with the platen roller by a predetermined time earlier than the printing start time and the running of the ink ribbon is started, the leading end of a sheet conveyed along the conveyance path is the thermal head. When the time required from the time when the paper passes from the upstream side to the downstream side to the printing start time is shorter than the predetermined time, the thermal head is brought into contact with the platen roller earlier than the predetermined time and the ink is A thermal transfer printer, comprising: means for controlling the ribbon to start running.