JPH11235837A - Thermal printing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control density in an increased and decreased manner when printing is implemented to a medium to be printed having various hardness in a thermal printing unit to execute printing by putting a thermal head in contact with the medium to be printed. SOLUTION: The hardness of a medium P' to be printed is recognized on the basis of a kind of the medium P' to be printed, and a head compression lever 16 is swung by a head compression motor 18 in order to increase and decrease urging force by a head compression spring 17, thereby controlling the head pressure of a thermal head 13 secured to a swingable head angle 14 in accordance with the medium to be printed. As such, the head pressure of the thermal head 13 can be controlled in increased and decreased relation in accordance with a detected hardness of the medium P' to b printed, so that printing can be conducted in a most suitable printing density irrespective of the hardness of the medium P' to be printed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head which is capable of moving back and forth with respect to a print medium conveyed in a predetermined feed direction and in which a row of heating elements is arranged at right angles to the conveyance direction of the print medium. More particularly, the present invention relates to a thermal printing apparatus capable of printing on print-receiving media having different hardnesses.

[0002]

2. Description of the Related Art Conventionally, a thermal print head provided with a thermal head capable of moving back and forth with respect to a print medium conveyed in a predetermined feed direction and having a row of heating elements arranged at right angles to the transport direction of the print medium. Tape printers and card printers were known as devices. However, a tape printer is a printing device dedicated to a tape made of a soft and thin material, and a card printer is a printing device dedicated to a card made of a hard and thick material.

[0003]

Among these printing apparatuses, there are not so many known apparatuses that print on a medium to be printed having different hardnesses of soft and hard. When printing on a soft print medium and a hard print medium such as a plastic plate, there is a problem that either print density does not become an appropriate density.

For example, when printing is performed on a soft print medium with a thermal printing apparatus in which a print pressure for printing a hard print medium at an appropriate density and an energizing time to a thermal head are set, the print pressure becomes high. Therefore, there has been a problem that the heating point portion of the thermal head bites into the surface of the print-receiving medium, so that the heat radiation effect of the thermal head is deteriorated, and a printed image is tailed. SUMMARY OF THE INVENTION An object of the present invention is to provide a thermal printing apparatus that performs printing with an accurate print density corresponding to the hardness of a non-printing medium in view of such a problem.

[0005]

A thermal printing apparatus according to the present invention is capable of moving back and forth with respect to a print medium conveyed in a predetermined feed direction and forming a row of heating elements at right angles to the conveyance direction of the print medium. In a thermal printing device that has a thermal head that is oriented in the direction and presses the thermal head with a predetermined head pressure against the print medium in the transported state and prints on the surface of the print medium, the type of hardness of the print medium is detected. hand,
The head pressure is controlled to increase or decrease according to the type of the hardness of the detected print medium, and further, a width is detected in a direction perpendicular to the transport direction of the print medium, and the head is controlled in accordance with the width. It is desirable to control the increase and decrease of the pressure.

[0006] Alternatively, a thermal head is provided which is capable of moving back and forth with respect to a print medium conveyed in a predetermined feed direction and in which a row of heating elements is arranged at right angles to the conveyance direction of the print medium. In a thermal printing apparatus in which a thermal head is pressed against a medium at a predetermined head pressure and printing is performed on the surface of a print-receiving medium, the type of hardness of the print-receiving medium is detected, and the detected type of hardness of the print-receiving medium is detected. The energizing time to the heating element of the thermal head is controlled to increase or decrease according to the width of the thermal head. Further, the width is detected in the direction perpendicular to the transport direction of the printing medium, and the heating element of the thermal head is corresponding to this width. It is desirable to control the increase and decrease of the energization time to the power supply.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A thermal printing apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a front view of a thermal printing apparatus. FIG. 2 is a schematic diagram of a print system including print data input means. FIG. 3 is a plan view of the thermal printing apparatus. FIG. 4 is a block diagram illustrating an electrical configuration of the thermal printing apparatus. FIG. 5 is a flowchart showing the printing operation of the thermal printing device.

The printing apparatus 1 prints character data and format data transferred from a personal computer 2 (hereinafter referred to as a "personal computer 2") as an external device as a print data input means shown in FIG. Based on the data, printing is performed on a plate-shaped print medium P such as hard acrylic shown in FIG. 3 or a sheet-shaped print medium P ′ such as soft vinyl chloride shown in FIG. When the printing medium P ′ is to be printed, the operator supplies the printing medium P ′ manually, and when printing the sheet-shaped printing medium P ′, the printing medium P ′ wound in a roll shape is paired with a pair of mounting rollers. 4a and 4b, and the leading end is pulled out and supplied.

A conveying guide 5 is provided in the printing apparatus 1 at a position slightly leftward in the center of FIG. 1, and the conveying guide 5 has a pair of left and right guide plates 5a and 5b facing each other as shown in FIG. It is provided so as to be freely movable as it is, and is moved so as to move in the direction of contact and separation centering on the center of the portion sandwiched between the guide plates 5a and 5b by a connecting member (not shown). It is supposed to. As shown in FIG. 1, a slide volume 6 for detecting a moving amount of the guide plate 5a is provided below one of the guide plates 5a, and detects a width of the printing medium P from the moving amount of the guide plate 5a. Things.

A transport roller 7 and a pair of cleaning rollers 8 are provided downstream of the transport guide 5 in the transport direction (rightward in FIG. 1). The transport roller 7 rotates by the drive of the transport motor 9 to transport the print medium P, and the cleaning roller 8 removes dust and dirt on the print surface of the print medium P. The swing member 12 is supported and urged toward the transport roller 7 by the tension of the spring 11, and is rotatably provided at an end portion.

The thermal head 13 is arranged such that the longitudinal direction of the row of heating elements of the thermal head 13 is perpendicular to the direction in which the print medium P is conveyed. It is provided on the angle 14. The ink ribbon cassette 15 has an ink ribbon inside, and is wound by driving the transport motor 9.

A head pressure spring 17 is provided at an end 14a of the head angle 14 between the head pressure lever 16 and the head pressure lever 16. The head pressure lever 16 comes into contact with a cam 19 which is rotated by driving a head pressing motor 18. The head pressure lever 17 swings to apply a load to the head pressure spring 17.

In the direction opposite to the head pressure spring 17 at the end 14a of the head angle 14, a head pressure spring 1 is changed by the swing of the head pressure lever 16.
The head angle 14 is provided so as to be balanced with the seven tensions, so that the head angle lever 14 swings in the direction of contacting and separating from the platen roller 21 by the swing of the head pressure lever 16.

The platen roller 21 rotates at the same speed as the transport roller 7 by the drive of the motor 9 through a known transmission means such as a gear, and faces the thermal head 13 in the same manner as the transport roller 8. It is provided.
The transport roller 22, like the transport roller 7, is provided so as to be rotated by the drive of the transport motor 9 via a known transmission means such as a gear.

The reflection sensor 23 provided on the inclined surface downstream of the placement roller 4b in the transport direction is used to print the soft print medium P 'placed on the placement rollers 4a and 4b in a state where it is pulled out to the transport roller 7. The medium P ′ is detected, and is used to determine the type of the print target medium by using the fact that the hard print target medium P placed on the transport guide 5 cannot be detected. Further, the reflection sensor 24 provided on the swinging member 12 includes
This detects the leading end of P 'and is used for controlling the start of printing.

The electrical configuration of this embodiment will be described with reference to FIG. The CPU 25 controls the operation of the thermal printing apparatus 1 based on a control program previously written in the ROM 26 and print data sent from the personal computer 2 via the communication interface 27. In addition, a RAM 28, an output interface 29, an A / D converter 30, an input interface 31, and a counter timer 32 are connected.

The ROM 26 stores a program for controlling the printing apparatus, including a printing processing program, constants for calculating a printing pressure for each type of printing medium, font data, and the like. The print data sent from the printer 2 and the print pressure data read out by the print pressure control program are temporarily stored.

A motor drive circuit 33 and a head control circuit 34 are connected to the output interface 29. The motor drive circuit 33 includes the transport motor 9 and the head pressing motor 1
The head control circuit 34 drives and controls the thermal head 13.

The A / D converter 30 is connected with a thermistor 35 for detecting the temperature of the thermal head 13 and a slide volume 6 linked to the movement of the guide plate 5a. It converts analog data output from the thermistor 35 and the slide volume 6 into digital data and provides the digital data to the CPU 25.

The input interface 31 is a reflection sensor 3
2 and the reflection sensor 33 are connected, and the counter timer 32 counts the time such as the energizing time of the thermal head 5.

Next, the printing process for the hard print medium P will be described with reference to the flowchart of FIG. First, when the power of the present apparatus is turned on, each device or component is initialized (S1), and thereafter, the apparatus enters a print data input wait state.

Next, when print data including data for starting the printing process is input from the personal computer 2, it is determined whether all the print data has been received (S2). All the print data is received and stored in the RAM 28. And preparation for printing. Here, the print data includes the type of the print-receiving medium P, the size of the print-receiving medium P, the character type and the character size, and the format data such as the number of rows and the margin.

Next, the resistance value r of the slide volume 6 moved along with the guide plate 5a of the transport guide 5 previously moved according to the width of the medium P to be printed is A / D.
The width R of the print-receiving medium P is obtained from the resistance value r and the numerical value table stored in the ROM 26 by reading through the converter 30 (S3).

Next, it is determined whether the type of the printing medium P is a hard printing medium (S4). Here, in the case of the hard print medium P, the reflection sensor 23 does not detect the hard print medium P, so it is determined that the print medium is hard, and then the print setting processing (S5) for the hard print medium is executed. Although not shown, if the type of medium input by the operator in S2 is soft, an error process is performed because the type is different from the type of medium detected by the reflection sensor 23.

First, the print setting process for the hard print medium is performed as follows.
The width R of the print medium P is compared with the length L of the heating element array of the thermal head (S20).
If the width R of the print data is smaller than the length L, it is determined whether the width of the print data stored in the RAM 28 is within the width R of the print medium P (S21). If there is, it is determined whether the width of the hard medium is 22 mm (S22). In S21, the print data has a width R.
If it exists outside, the printing process is stopped and error processing is performed.

If the width of the print medium P is equal to or larger than 22 mm in S22, the number of pulses X of the head pressing motor 15 for the head pressure suitable for the resistance value r is calculated. The number of pulses X is calculated based on the value calculation expression X = kr and stored in the RAM 28 (S23), and the print setting process for the hard print medium ends. If the width R of the print medium P is larger than the length L of the heating element row in S20, the pulse number Xmax is obtained. If the width of the print medium P is less than 22 mm in S22, the pulse number Xmin is obtained.
Is stored in the RAM 28 (S24, S25), and the print setting process (S5) for the hard print-receiving medium ends.

Subsequently, the number of motor pulses is read out from the RAM 28, and the head pressing motor 18 is driven based on the number of pulses, and the head pressure lever 16 swings via the gear group and the cam 19, so that the head pressing is performed. The head angle 14 swings in conjunction with this via the spring 17, and the thermal head 13 moves toward the platen roller 21 (S7).

The print medium P is being conveyed before the movement of the thermal head 13, and the thermal head 13 descends at the timing when the print medium P passes through the leading end.
In accordance with this, print data is supplied and printing is performed (S
8). After the printing on the print medium P is completed, the thermal head 13 is double-acted to protect the thermal head 13 before the rear end of the print medium P passes (S9). The number of sheets is determined (S10), and if there is the next print data, S7, S8, and S9 are repeated, and printing is performed in the same manner as described above. At S10, if there is no remaining number of sheets, the printing process for this print data is terminated,
The next print data reception standby state is set (S2).

When printing on a soft print-receiving medium P ',
In S4, it is determined that the medium is a soft print-receiving medium P ′,
Subsequently, a print setting process (S6) for the soft print medium is executed.

First, the print setting process for a soft print-receiving medium is as follows.
The width R of the printing medium P 'is compared with the length L of the heating element array of the thermal head (S30). If the width R of the printing medium P' is smaller than the length L, then It is compared whether the width of the print data stored in the RAM 28 is within the width R of the print-receiving medium P '(S31). If the print data is within the width R, then the width of the hard medium is 22 mm. Is determined (S32). If the print data exists outside the width R in S31, the print processing is stopped and error processing is performed.

If the width of the print medium P 'is equal to or greater than 22 mm in S32, the number of pulses X' of the head pressing motor 15 for the head pressure suitable for the resistance value r is calculated. k ′ is obtained from the ROM 26,
The number of pulses X ′ is calculated based on the arithmetic expression X ′ = k ′ · r, and R
The data is stored in the AM 28 (S33), and the print setting process for the hard print-receiving medium ends. If the width R of the print-receiving medium P 'is larger than the length L of the heating element row in S30, the number of pulses X'm
If ax is smaller than 22 mm in width of the print-receiving medium P ′ in S32, the pulse number X′min is stored in the RAM 28 (S3
4, S35), print setting processing for a soft print-receiving medium (S6)
Ends.

Subsequently, the head pressing motor 19 is driven based on the stored pulse number X 'to perform a printing process (S7, S8, S9, S10).

Here, since the head pressing motor 18 is driven by the number of pulses determined in accordance with the type and width R of the printing medium, if the width is the same, the hard printing medium P
The position of the cam 19 and the head pressing lever 16 move to the position shown by the solid line in FIG.
Then, the position of the head pressing lever 16 moves to the position shown by the dotted line, and printing is performed at an appropriate print density with a lower head pressure than the hard print medium P on the soft print medium P ′. Further, when the width R is changed, printing is performed at a print density suitable for the width R on each print-receiving medium.

Next, a case where the energization time is controlled as another print density control will be described with reference to the flowcharts of FIGS. The ROM 26 stores a print energization time control program and an initial energization time corresponding to the head temperature for each type of medium.

As in the flowchart of the printing process shown in FIG. 5, initialization is performed (S40), and data is received (S40).
41) When the resistance value of the slide volume 6 is read (S42), it is determined whether the medium is a hard medium (S4).
3) If the print medium P is a hard print medium, the width R of the print medium P is compared with the length L of the heating element array of the thermal head (S44). Is the length L
If the print data is smaller than the width R, it is determined whether the width of the print data is within the width R of the print medium P (S45).
If it is within the range, the width of decrease x in the energization time is subsequently determined and R
It is stored in the AM 26 (S46).

In step S46, the reduction width x for reducing the power-on time of the heating element of the head 1 is obtained by the following equation from the resistance value r read from the slide volume 6. x = k · (Rh-r) k: coefficient (hard print medium) Rh: resistance value of the same size as the head width

Subsequently, the head temperature is read by the thermistor 35 built in the thermal head 13 and the initial temperature corresponding to the head temperature previously set and stored in the hard print medium P so that the power can be supplied at the optimum density. The energizing time Ta is read from the ROM 26 (S47), and from the initial energizing time Ta, the decrease width x of the energizing time calculated previously is x.
Is subtracted to obtain the actual energizing time T (S48), and printing is performed based on the energizing time T (S49).

Subsequently, the remaining number is determined (S5).
0), if there is a next, the head temperature is read again by the thermistor 35 to print the next print medium P, and the initial set temperature Ta is read from this head temperature (S47), T is calculated and printing is performed (S48). If there is no remaining number in S50,
This printing process is completed, and a next print data reception standby state is set (S41).

If the width R of the print medium is larger than the length L of the print area of the thermal head 13 in S44 and it is determined that R> L, the amount of heat generation does not need to be reduced, and the reduction x = 0. , And printing is performed in the initial setting energization time Ta.

When the sheet-like soft print-receiving medium P 'is conveyed, if it is determined in S43 that the medium is a soft print-receiving medium, the printing process of the soft print-receiving medium is executed (S52). A comparison is made between the width R of P ′ and the length L of the heating element array of the thermal head (S60).
If the width R of the print-receiving medium P is smaller than the length L, then it is compared whether the width of the print data is within the width R of the print-receiving medium P (S61), and the print data is within the width R. Then, a decrease width x 'of the energization time is obtained and stored in the RAM 26 (S62).

In step S62, the reduction width x for reducing the power-on time of the heating element of the head 1 is obtained by the following equation based on the resistance value r read from the slide volume 6. x ′ = k ′ · (Rh−r) k ′: coefficient (soft print medium) Rh: resistance value of the same size as the head width

Subsequently, the head temperature is read by a thermistor 35 built in the thermal head 13 and the head temperature is set and stored in advance in the soft print medium P 'so that the power can be supplied at an optimum density. The initial energizing time Ta 'is read from the ROM 26 (S63), and the actual energizing time T' is obtained by subtracting the previously calculated decrease x 'in the energizing time from the initial energizing time Ta' (S63).
64), and printing is performed based on the energization time T ′ (S)
65).

Subsequently, the remaining number is determined (S6).
6) If there is a next, the head temperature is read again by the thermistor 35 to print the next print medium P, the initial set temperature Ta 'is read from this head temperature, and the energization time T' is calculated. And printing is performed (S6
3, S64, S65).

The method of detecting and inputting the hardness of the printing medium is not limited to the present embodiment, and the type and detection method of the sensor may use a known technique, and a detecting means is provided. Instead, the input data of the type of the print-receiving medium may be used. Similarly, the method of detecting and inputting the width of the print-receiving medium is not limited to the present embodiment.

[0045]

According to the present invention, the head pressure of the thermal head can be increased or decreased in accordance with the detected hardness of the printing medium, and printing can be performed at an optimum printing density regardless of the hardness of the printing medium. Can be. Further, the head pressure of the thermal head can be controlled to increase or decrease according to the width of the print medium, and printing can be performed at an optimum print density even with print media having different widths and different hardnesses.

Further, it is possible to increase or decrease the energizing time to the heating element of the thermal head in accordance with the detected hardness of the printing medium, so that printing can be performed at an optimum printing density regardless of the hardness of the printing medium. . Further, the energization time can be controlled to increase or decrease according to the width of the print medium, and printing can be performed at an optimum print density even with print media having different hardnesses and different widths.

[Brief description of the drawings]

FIG. 1 is a front view of a thermal printing apparatus.

FIG. 2 is a schematic diagram of a print system including print data input means.

FIG. 3 is a plan view of the thermal printing apparatus (with an ink ribbon cassette removed).

FIG. 4 is a block diagram illustrating an electrical configuration of the thermal printing apparatus.

FIG. 5 is a flowchart illustrating a printing process of the thermal printing apparatus.

FIG. 6 is a flowchart showing a print setting process for a hard print medium.

FIG. 7 is a flowchart showing print setting processing for a soft print-receiving medium.

FIG. 8 is an enlarged front view of the vicinity of a thermal head of the thermal printing apparatus.

FIG. 9 is a flowchart showing a printing process according to another embodiment.

FIG. 10 is a flowchart showing a printing process on a flexible print-receiving medium according to another embodiment.

[Description of sign]

 REFERENCE SIGNS LIST 1 printing device 2 data input means 4 a, 4 b placement roller 5 guide member 6 slide volume 7 transport roller 8 cleaning roller 9 motor 13 thermal head 14 head angle 15 ink ribbon 16 head pressing lever 17 head pressing spring 18 head pressing motor 19 cam 21 Platen Roller 22 Conveyance Roller 23 Reflection Sensor 25 CPU 26 ROM 27 Communication Interface 28 RAM 29 Output Interface 30 A / D Converter 31 Input Interface 32 Counter Timer 35 Thermistor

Claims (4)

[Claims] A thermal head that is capable of moving back and forth with respect to a print medium conveyed in a predetermined feed direction and that has a row of heating elements arranged at right angles to the conveyance direction of the print medium.
In a thermal printing apparatus for printing on the surface of a print-receiving medium by pressing a thermal head against a print-receiving medium in a transport state at a predetermined head pressure, the type of hardness of the print-receiving medium is detected, and the detected print-receiving medium is detected. A thermal printing apparatus characterized in that head pressure is controlled to increase or decrease according to the type of hardness of a medium. 2. The thermal printing apparatus according to claim 1, wherein a width is detected in a direction perpendicular to a conveying direction of the medium to be printed, and a head pressure is increased or decreased according to the width. 3. A thermal head which is capable of moving back and forth with respect to a print medium conveyed in a predetermined feed direction and has a row of heating elements arranged at right angles to a conveyance direction of the print medium.
In a thermal printing apparatus for printing on the surface of a print-receiving medium by pressing a thermal head against a print-receiving medium in a transport state at a predetermined head pressure, the type of hardness of the print-receiving medium is detected, and the detected print-receiving medium is detected. A thermal printing apparatus, wherein the energization time to a heating element of a thermal head is increased or decreased according to the type of hardness of a medium. 4. The method according to claim 3, wherein a width is detected in a direction perpendicular to the conveying direction of the medium to be printed, and the energization time to the heating element of the thermal head is increased or decreased in accordance with the width.
Thermal printing device described in