JPS61237582A - Thermal transfer type video printer - Google Patents

Abstract

PURPOSE:To decrease the influence of an ink-ribbon driving system on a printing picture by providing a D.C. motor to the driving system of an ink-ribbon winding mechanism and by driving the said motor with a signal delayed to a control signal for platen for a specified length of time. CONSTITUTION:When printing, the control signal SMP is supplied to an input terminal at every constant period T. During the latter half of the period T, the picture elements of 1-line share are printed by a thermal head. Also, the said control signal is inputted to a stepping motor control circuit 2 as well as to a phase shift circuit 4. From the circuit 4, a pulse that rises delaying by t1 is obtained and further by the second phase shift circuit 5, a pulse whose width is t2 is obtained. This pulse is made a motor-drive output pulse and is supplied to the D.C. motor 40. Consequently, the slackening part of the ink- ribbon driven by a stepping motor 32 is wound immediately after the control signal SMP.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal transfer video printer having a thermal head, a platen, an ink ribbon, etc. A DC motor is used in the system, and by driving the DC motor with a Norms voltage of a predetermined time width that is delayed by a certain time with respect to the drive control signal for the platen during printing, the drive system for the ink ribbon can control the print image. This is to reduce the impact of

[Conventional technology]

In recent years, VTR (Video Tape Record)
With the spread of video cameras, personal computers, etc., there is a demand for so-called video printers that can print those images on plain paper, etc., and video printers based on various methods have been proposed.

A thermal transfer video printer is a type of video printer, and has superior stability, ease of maintenance, and low noise compared to other types of printers.

In this thermal transfer type video printer, for example, an ink ribbon whose surface is coated with sublimable dye ink is interposed between a thermal head having a heating resistor corresponding to the number of pixels and plain paper, etc., and the heating resistor of the thermal head is Printing is performed by vaporizing the sublimable dye ink by the heat generated and transferring it to the plain paper or the like.

In the case of color printing, Y is the three primary colors of subtractive color mixture.
It is necessary to overlap the colors in the order of (yellow), M (magenta), and C (cyan). Furthermore, various methods for expressing gradations have been proposed, and so-called full-color display has become possible.

Next, FIG. 4 schematically shows the principle of operation of color printing by the thermal transfer video printer.

In the figure, an ink ribbon 40 is placed between a thermal head 41 having a number of heating resistors corresponding to the number of pixels and a paper 42 such as plain paper. On the ink ribbon 40, a yellow ink surface 43, a magenta ink surface 44, and a cyan ink surface 45 having the size of a print image are sequentially formed.

Force 2 - When printing, for example, the thermal head 41 prints an image vertically one column at a time on the yellow ink surface 43, then returns the paper 42 to its original position, and this time prints on the magenta ink surface 44, and finally prints on the magenta ink surface 44. , return the paper to its original position and place the cyan ink surface 45
A single color image can be obtained by printing.

At this time, the ink ribbon 40 only moves in one direction (arrow direction in the figure), but the paper 42 returns to its original position each time the color of the ink ribbon 400 changes. It is necessary to perform alignment with the surfaces of each color. This positioning is performed, for example, on the paper 42.
If it is wound around a cylindrical platen, this can be done by simply driving the platen in one direction, which simplifies the drive system.

Generally, the ink surfaces 43, 44, and 45 of the three primary colors of the ink ribbon 40 are separated from the next image by a gap, assuming that one set of -images is included. - The driving of the ink ribbon 40 while printing an image and the driving of the ink ribbon 40 to wind up the gap in the ink ribbon to print the next image are determined by the winding speed. are set differently. Normally, the speed at which the ink ribbon 40 is driven to wind up the gap is set higher than the speed at which it is driven during printing.

Generally, in a thermal transfer video printer using a platen, a pulse motor is used to drive the platen, and a DC motor is used to wind up the ink ribbon 40, and the DC motor is driven with a constant voltage. It is rolled up so that there is no sagging.

[Problem that the invention seeks to solve]

As mentioned above, in thermal transfer video printers that use a platen, ink ribbon, etc., a stepping motor is generally used to drive the platen, and a DC motor driven at a constant voltage is used to wind up the ink ribbon. It is. For this reason, during printing, a constant tension is always applied to the ink ribbon by the DC motor, which may cause the ink ribbon to rub against the paper, resulting in unwanted color or smearing. . This phenomenon is particularly likely to occur at the beginning and end of the ink ribbon.

Even though the DC motor can be supplied with a drive current corresponding to torque fluctuations, the drive system of the ink ribbon may affect the printed image as in the phenomenon described above.

The present invention was made in view of these problems.)
An object of the present invention is to provide a thermal transfer video printer in which the influence of an ink ribbon drive system using a DC motor on printed images is significantly reduced.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention brings paper into close contact with a platen, and heats an ink ribbon interposed between the paper and the thermal head with the thermal head. In a thermal transfer video printer for printing on the paper, the ink ribbon winding drive system uses a DC motor, a delay circuit outputs a signal delayed by a certain period of time with respect to the platen drive control signal, and the ink ribbon winding drive system uses a DC motor. The present invention is characterized in that it is configured to include a drive circuit that drives the DC motor with a pulse voltage of a constant time width based on the output signal of the delay circuit.

[Effect]

In the thermal transfer video printer according to the present invention, during printing, the DC motor is pulse-driven for a predetermined time with a predetermined delay by the delay circuit and the drive circuit in response to the drive control signal for the platen.

Therefore, after the paper and the ink ribbon are driven by the drive of the platen, the ink ribbon is wound up by the ink ribbon take-up drive system within the predetermined time. Further, after the predetermined time, one line of pixels is printed by the thermal head.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a thermal transfer video printer according to the present invention will be described below with reference to the drawings. This thermal transfer video printer is capable of color printing.

First, the outline of the mechanical section of the thermal transfer video printer is schematically shown in the first part. The mechanism section consists of a drive system for the platen 31 and a drive system for the ink ribbon 3. Above platen 3
1 is rotationally driven by a stepping motor 32 via a belt 33.

The ink ribbon 37 is wound from a ribbon supply reel 38 to a ribbon take-up reel 39 via a ribbon guide 35, a ribbon guide roller 36, and the like.

The ink ribbon take-up reel 39 is rotationally driven by a DC motor 40 via a belt 41.

Furthermore, a sheet of paper 42 is brought into close contact with the platen 31 . During printing, the thermal head 34 is pushed toward the platen 31, and the paper 42 and the ink ribbon 37 are pressed against the platen 31 with a constant pressure. In this state, the stepping motor 32 and the DC motor 4G are driven.

In addition, the above ink lipo/37 includes two for color printing,
Yellow, magenta, and cyan ink surfaces are sequentially formed in sizes corresponding to the print area. During printing, the stepping motor 32 drives the planar 231 in one step to drive the paper 42 and the ink ribbon 37 by a distance corresponding to one line of print image movement. Printing is performed. Next, by controlling the rotation of the platen 310, the uninked surface and the paper 42 are
After alignment with the magenta ink surface, printing is performed on the magenta ink surface. Finally, after the paper 4± and the cyan ink surface are aligned, printing is performed on the cyan ink surface, and color printing is completed.

During printing, the platen 31 rotates in one direction as shown by the arrow in the figure, and the ink ribbon 37 is also driven in one direction as shown by the arrow.

Next, Figure 2 shows a block diagram of a drive control section for the stepping motor 32 and the DC motor 40, and Figure 2 shows a timing chart of the drive control section during printing.

During printing, a control signal SMP shown in the first diagram a is supplied to the input terminal 1 at regular intervals T. In the second half of this constant period T, one line of pixels is printed by the thermal head 34.

The control signal 8MP is input to the stepping motor control circuit 2, and the stepping motor control circuit 2 receives the control signal SMP and drives the motor drive circuit 3. The step/g motor 32 rotates one step by the output of the motor drive circuit 3.

Further, the control signal SMP is the stepping mode 1'
The signal is input to the control circuit 2 and also to the first phase shift circuit 4. The first phase shift circuit 4 outputs to the second phase shift circuit 5 a signal φ□ which rises with a delay of time tX with respect to the control signal SMP, as shown in the second diagram. The second phase shift circuit 5 outputs the signal φ2, which is at a high level, to the motor control circuit 6 for a certain period of time t after the rise of the signal φ, as shown in FIG. The motor control circuit 6 drives the motor drive circuit 7 during the time t, and the motor drive circuit 7, as shown in Figure d,
During the time t2, a constant pulse voltage is supplied to the DC motor 40. The DC motor 40 operates at the time t,
It operates only during this period, and takes up the slack of the ink lipo/37 driven by one step rotation of the stepping motor 32 immediately after the control signal 8MP is received.

After the time t2, the heat generation of the thermal head is controlled in accordance with one line of pixels, and one line of printing is performed.

In this way, the DC motor 40 is not driven when the stepping motor 32 rotates and when the thermal head 34 prints, and does not apply unnecessary tension to the quick ribbon 3f.

〔Effect of the invention〕

As described above, in the thermal transfer video printer according to the present invention, unnecessary tension is not applied to the ink ribbon during printing when the platen is driven and when printing is performed using heat generated by the thermal head.

Therefore, the influence of the ink ribbon drive system on printed images can be significantly reduced, and the intended purpose of the present invention can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a schematic view of the mechanism of a thermal transfer video printer according to the present invention. FIG. 2 is a block diagram of a drive control section for a stepping motor and a DC motor in the mechanism section, and FIG. 3 is a timing chart of the drive control section. FIG. 4 is a schematic diagram for explaining the operating principle of color printing by a thermal transfer video printer. 2...Stepping motor control circuit 3.7.
... Motor drive circuit 4 ... First phase shift circuit 5 ... Second phase shift circuit 6 ... Motor control circuit 31 ... Platen 32 ... Stepping motor 34 ... Thermal head 37 ... Ink ribbon 38 ... Ribbon supply reel 39 ... Ribbon take-up reel 40 ... DC motor 42 ... Paper

Claims (1)

[Claims] The ink ribbon uses a DC motor in a thermal transfer video printer that prints on the paper by bringing the paper into close contact with a platen and heating the ink ribbon interposed between the paper and the thermal head with the thermal head. a winding drive system, a delay circuit that outputs a signal delayed by a certain time with respect to the platen drive control signal, and a drive circuit that drives the DC motor with a pulse voltage of a certain time width using the output signal of the delay circuit. A thermal transfer video printer, characterized in that the DC motor is driven in pulses with a predetermined time delay relative to the drive of the platen during printing.