JPH11235838A - Thermal printing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To print with a precise printing density corresponding to the change of the width of a medium to be printed, by a method wherein a widthwise dimension is detected normal to the feeding direction of a medium to be printed so as to increasingly and decreasingly control an energizing time in response to this detected widthwise dimension. SOLUTION: A slide volume 6 for detecting the amount of movement of a guide plate 5a is provided below the one guide plate 5a of a horizontal pair of guide plates 5 locating at the near center of a printing device 1 so as to detect the width of a medium to be printed P from the amount of movement of the guide plate 5a. From the value of resistance read from this slide volume 6, the reduction range for reducing the energizing time to the heating element of a thermal head 13. In succession, from an initial energizing time corresponding to a head temperature, which is set in advance so as to energize at the optimum density at the head temperature read from a thermistor built in the thermal head 13, the reduction range of the energizing time calculated some time ago is subtracted so as to obtain an actual energizing time.

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. The present invention relates to a thermal printing device provided.

[0002]

2. Description of the Related Art Conventionally, tape printers and card printers have been known as such a thermal printing device, and a printing medium such as a tape or a card used for the printing device has a length corresponding to the length of a heating element array of a thermal head. They were used from wide to narrow widths.

[0003] As a thermal printing apparatus for printing on a medium to be printed having different widths, a thermal printing apparatus for label tapes described in JP-A-8-34146 has been known. In this thermal printing apparatus, when a label having a narrow width with respect to the length of the element array of the thermal head is printed, the contact area is reduced and the printing pressure is changed as compared with a label having a large width. It was necessary to apply a printing pressure corresponding to each width of the label to the thermal head. In this printing device, when a sliding member serving as a label tape conveyance guide is brought into contact with the side edge of the label, the swinging member and the adjusting cam work in conjunction with the movement of the sliding member, so that the head cover moves relative to the platen roller. To make the printing pressure of the thermal head appropriate.

[0004]

However, such a printing apparatus has a structure in which a swinging member, an adjusting cam and the like are provided between a sliding member and a head cover. Had become. 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 a change in the width 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 with a 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 thermal head is perpendicular to the feed direction of the print medium. The width dimension is detected in the direction, and the energization time is controlled to increase or decrease according to the detected width dimension.

[0006]

DETAILED 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.
1 is a schematic diagram of a printing 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.

[0007] The printing apparatus 1 is a hard disk based on print 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. The printing is performed on a plate-shaped printing medium P such as acrylic, or a sheet-shaped printing medium P ′ such as soft vinyl chloride indicated by a dotted line. When the sheet P is supplied manually to print the sheet-shaped print medium P ′, the print medium P ′ wound in a roll is placed on a pair of placement rollers 4a and 4b, Is drawn out and supplied.

A conveying guide 5 is provided in the printing apparatus 1 in a slightly leftward direction 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 so that the longitudinal direction of the thermal head 13 is perpendicular to the transport direction of the print medium P, and the heating element array corresponding to the width of the print medium P is formed. It is a common thing to have. The ink ribbon cassette 14 has an ink ribbon inside, and is wound by driving the transport motor 9.

The platen roller 15 is rotated by the motor 9 through a known transmission means such as a gear so as to rotate at the same speed as the transport roller 7 and faces the thermal head 13 similarly to the transport roller 7. It is provided.
The transport roller 16 is provided so as to be rotated by the drive of the transport motor 9 via a known transmission means such as a gear, similarly to the transport roller 7.

The anti-winding roller 17 is provided in the vicinity of the downstream side of the ink ribbon cassette 14 and slightly above the conveyance path of the print medium P. After the sheet-shaped print medium P 'is printed, it is attached to the ink ribbon. The sheet is conveyed while being adhered, and is forcibly separated from being wrapped around the ink ribbon cassette 14.

A reflection sensor 18 provided on the swing member 12
Is for detecting the conveyance of the printing medium P, and the pressing plate 19 provided on the swinging member 12 also prevents the printing medium P from floating. The head pressing motor 20 drives the movement of the thermal head 13 with respect to the platen roller 15.

The electrical configuration of this embodiment will be described with reference to FIG. The CPU 23 controls the operation of the thermal printing apparatus 1 based on a control program previously written in the ROM 24 and print data sent from the personal computer 2 via the communication interface 25. In addition, a RAM 26, an output interface 27, an A / D converter 28, an input interface 29, and a counter timer 30 are connected.

The ROM 24 includes a program for controlling the printing apparatus including a program for a printing process, an initial energizing time Ta corresponding to a head temperature described later, a resistance value r of the slide volume, and a width R of the printing medium P. A numerical table indicating the relationship, font data, and the like are stored. The RAM 26 temporarily stores the print data sent from the personal computer 2 and the energizing time calculated by the program for controlling the energizing time of the print.

A motor drive circuit 31 and a head control circuit 32 are connected to the output interface 27. The motor drive circuit 31 includes a transport motor 9 and a head pressing motor 2
The head control circuit 32 drives and controls the thermal head 13.

The A / D converter 28 is connected to a thermistor 33 for detecting the temperature of the thermal head 13 and the slide volume 6 which is linked to the movement of the guide plate 5a. It converts analog data output from the thermistor 33 and the slide volume 6 into digital data and provides the digital data to the CPU 23.

The input interface 29 has a sensor 18
And the release switch 34 are connected, and the release switch 3
Reference numeral 4 denotes a mode in which when the width of the print medium P is smaller than the width of the thermal head 13, the operator cancels the mode in which the amount of heat generated by the thermal head 13 is reduced.

The counter timer 30 includes the thermal head 13
And counts the energizing time calculated based on the temperature of the thermal head 13 detected by the thermistor 33 and the width of the print medium P read by the slide volume 6. Is counted.

Next, the printing process 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 the 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 26. 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 24 (S3).

Next, it is determined whether the type of the printing medium P is a hard printing medium (S4). If the print data from the personal computer 2 is hard, the width R of the print medium P is compared with the head width of the thermal head (print area length y) (S5). If the width R of the print medium P is smaller than the head width y, it is determined whether the release switch is ON (S6).

If the release switch is ON, the width of the dot to be energized in the print data stored in the RAM 26 is compared with the width R of the print medium P (S7).
If the print data fits within the width R, a decrease width x of the energization time is subsequently obtained and stored in the RAM 26 (S8). If the print data exists outside the width R in S7, the printing process is stopped.

In step S8, the reduction width x for reducing the power supply time to the heating element of the thermal head 13 from the resistance value r read from the slide volume 6 is obtained by the following equation. x = k · (Rh−r) k: coefficient Rh: resistance value with the same head width

Subsequently, the head temperature is read from the thermistor 33 incorporated in the thermal head 13, and an initial energizing time Ta which is preset and stored in accordance with the head temperature is stored in the ROM 24 so that energization can be performed at an optimum density. It is read (S9), and the decrease width x of the previously calculated energization time is subtracted from the initial energization time Ta, and the actual energization time T
Is obtained (S10), and then printing is performed based on the energization time T (S11).

Subsequently, the remaining number is determined (S1).
2) If there is a next, the head temperature is read again by the thermistor 33 to print the next print medium P, and the initial set temperature Ta is read from this head temperature (S9), and the energization time is subsequently T is calculated and printing is performed (S10, S11). If there is no remaining number of sheets in S12, this printing process is completed, and the next print data reception standby state is set (S2).

In step S5, it is determined that the width R of the print medium is wider than the print area length y of the thermal head 13 and that R> y.
Alternatively, if it is determined in step S6 that the release switch 34 has been turned on, the amount of heat generation need not be reduced, and the reduction amount x
= 0, and printing is performed during the initial setting energization time Ta.

When the sheet-like soft print medium P 'is transported, it is determined in S4 that the print medium P is a soft print medium based on the data of the type of the print medium input from the personal computer 2. Then, the printing process is executed with the values of the initial setting energization time Ta 'and the decrease width x' different from the printing on the hard print medium P (S13).

FIG. 6 shows another embodiment. In the drawing, a plurality of plate-like print-receiving media P which are detachable from the thermal printing device 40 and are slightly leftward from the center of the thermal printing device 40 are shown. A plate cassette 41 to be accommodated is mounted, and one print medium P is extruded rightward in the figure from the plate cassette 41 and supplied for printing.

The plate cassette 41 has an accommodating portion 41a for accommodating a plurality of print mediums P arranged in a vertical direction.
A thermal printing device 4 is provided on the bottom 41b of the accommodation portion 41a.
A groove 41c formed toward the thermal head 42 of the thermal printing apparatus 40 is provided in a state where the supply slider 43 is slidably provided in the groove 41c.

The supply slider 43 slides along the groove 41c to convey the printing medium P to the thermal head 42 side.
A protrusion 43b is formed on the upper surface side of the upper surface 3a and slightly lower than the height of the print medium P in contact with the side surface of the print medium P.

The convex pin 44 engaging with the concave portion 43a of the supply slider is tensioned on a pair of pulleys 45a and 45b provided below the plate cassette mounting portion 40a of the thermal printing device 40 on which the plate cassette 41 is mounted. The pulleys 45a and 45b are fixed to a belt 46
Is rotated by the drive of a drive motor 51, which will be described later, so that the supply slider 43 is
To supply the print medium P to the thermal head side.

The number and shape of the convex pins 41d provided at the lower portion of the plate cassette 41 are determined according to the type of the plate cassette 41, and the sensor 47 provided on the plate cassette mounting portion 40a detects the convex pins 41d. By detecting, the type of the plate cassette 41 can be recognized, and the width of the printing medium P accommodated in the plate cassette can be recognized.

The transport rollers 48 and 49 and the platen roller 50 are the same as those in the above-described embodiment, rotate by the drive of the transport motor 51 and transport the print medium P. The cleaning roller 52 and the swinging rod 53 , Sensor 5
4. The thermal head 42, the ink ribbon cassette 55, and the head pressing motor 56 are the same as those in the above-described embodiment, and the electrical configuration and the printing process (not shown) are the same. Optimum printing is performed on the print-receiving medium P with a power-on time suitable for its width. .

As the width input means of this embodiment, a slide volume and a means for detecting the width based on the type of cassette are disclosed. However, the present invention is not limited to this embodiment, and comprises a large number of light emitting elements and light receiving elements. Width detection by a line sensor or encoder, or width data of data by input means may be used as is

[0037]

According to the present invention, even when a printing medium having a width smaller than the length of the heating element array of the thermal head is conveyed, the energization time to the heating element of the thermal head is adjusted according to the width. Since printing is performed by controlling the increase / decrease, high-quality printing without excessive print density and tailing can be performed.

[Brief description of the drawings]

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

FIG. 2 is a schematic diagram of a 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 operation of the thermal printing apparatus.

FIG. 6 is a thermal printing apparatus according to another embodiment.

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Thermal printing apparatus 2 Input means (personal computer) 5 Transport guide 5a Guide plate 5b Guide plate 6 Slide volume 7 Transport roller 8 Cleaning roller 9 Transport motor 13 Thermal head 14 Ink ribbon 15 Platen roller 16 Transport roller 18 Sensor 20 Head pressing motor 23 Print density control means (CPU) 24 RAM 26 ROM 30 Counter timer 31 Motor drive circuit 32 Head control circuit 33 Thermistor 34 Release switch

Claims (1)

[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 device that presses a thermal head against a print medium in a transport state with a predetermined head pressure and prints on the surface of the print medium, a width dimension is detected in a direction perpendicular to a feeding direction of the print medium. A thermal printing apparatus, wherein the energization time is controlled to increase or decrease according to the detected width dimension.