JPH03224766A - Color printer - Google Patents

Abstract

PURPOSE:To avoid the color deviation between the two colors to be printed first and the color to be printed second and later, by controlling the device concerned not to perform printing action during the period from the time when the paper feeding is started until the leading end and the rear end of the printing paper overlap each other on a platen, CONSTITUTION:When a paper 2 for printing is fed, one end thereof hits against the rear surface of the paper at a part in the vicinity thereof, and when the platen makes another turn, the two ends of the paper 2 to be printed are wound around the platen in the state that the two ends of the paper overlap each other and fixed. Keeping this overlaped state, after the position where the leading end and its vicinity arrive at the position of a thermal head 9, the printing of yellow color, the first color to be printed is started. During this printing action, the three elements, i.e., the platen 1, the printing paper 2, and the ink ribbon 5 rotate in one body. In other words, in order to make the two ends of the printing paper overlap each other completely, the printing paper 2 is rotated in advance by one turn, and after that, the printing action of yellow color, i.e.,the first color to be printed, is commenced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color printer applied to a color video printer.

[Summary of the invention]

This invention includes a platen whose outer periphery is shorter than the length of the printing paper, and a head that prints on the printing paper so that printing is performed with the front and rear edges of the printing paper overlapping each other. The printer is equipped with a paper feeding means that feeds the printing paper by sandwiching it between the printing paper and the platen, and starts the printing operation after the printing paper is wrapped around the platen in an overlapping manner. It is possible to prevent the printed color from being misaligned with the color printed from the second time onward and the printing position.

[Conventional technology]

Color video printers have been proposed for obtaining hard copies of images such as VTRs, video disc playback devices, and computer images. Three primary colors (yellow, magenta, cyan) are used as one of the printing methods of color video printers.
A sublimation thermal transfer method is known that uses an ink ribbon in which heat-sublimable dyes of each color are sequentially provided, and a thermal head.

In such a color video printer, printing is performed on photographic paper wrapped around a platen using a thermal head and an ink ribbon. As a method of winding photographic paper around a platen, a method of chucking one end of the paper is known, but this method requires a chucking mechanism and the mechanism becomes complicated. Furthermore, simply wrapping the photographic paper around the platen results in an unstable wrapping condition, which tends to cause misalignment of the printing position of each color. Therefore, we have proposed a method for stably wrapping the photographic paper around the platen by overlapping the front and rear edges of the photographic paper on the platen.
(See Japanese Patent Application No. 62-279564).

[Problem to be solved by the invention]

In a method in which three primary colors (yellow, cyan, and magenta) are printed sequentially, if the printing positions of each color do not match accurately, color misregistration will occur in the resulting hard copy. In the above-mentioned previously proposed printing mechanism, after the printing paper is fed, the first color, for example yellow, is printed while the leading edge of the printing paper is free. In this case, since the photographic paper does not overlap completely, the photographic paper cannot completely follow the movement of the platen, and the photographic paper lags behind the platen. When the next color, for example cyan, is printed, the photographic paper completely overlaps and follows the movement of the platen. There has been a problem in that the printing position is likely to be misaligned between the printed color and the second or later printed color.

Therefore, the object of this invention is to
To provide a color printer capable of preventing a printing position shift from occurring between colors printed the first time and thereafter.

[Means for Solving the Problems] This invention provides a method in which the length of the outer periphery is shorter than the length of the printing paper (2) so that printing is performed with the front end and the rear end of the printing paper (2) overlapping each other. platen (1), a platen (9) that prints on printing paper (2), and platen (1).
) is provided with paper feeding means (6, 7, 8) that feeds the printing paper (2) by sandwiching the printing paper (2) between them, and after the paper feeding operation is started, the front end and the rear end are connected to the platen (1).
) is a color printer provided with means for controlling the printing operation so as not to be performed until the printing operation overlaps the top of the printer.

(Function) This invention provides printing paper 2 when printing in three colors is performed.
The state of winding around the platen 1 is the same. Therefore, there will be no difference in the ability of the photographic paper 2 to follow the movement of the platen 1 between the first color printing and the second and subsequent color printing, and the printing position will not shift between each color. It can be prevented.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. FIGS. 1, 2, and 3 show the printing mechanism of this embodiment in the order of operation.

In the figure, 1 is a platen, 2 is photographic paper, 3 is a ribbon roll on the supply side, 4 is a ribbon roll on the take-up side, and 5 is stretched between ribbon rolls 4 and 5, and is fed from the supply side to the take-up side. The ink ribbon 6.7.8 is a pinch roller that rolls into contact with the platen 1. Further, numeral 9 indicates a thermal head for performing dot printing, and the thermal head 9 can be moved away from and into contact with the platen 1 by a moving mechanism (not shown). 10 is a guide provided so as to partially surround the periphery of the platen 1, 11 and 12 are paper feed guides, and 13 and 14 are paper discharge guides.

The ink ribbon 5 has repeated regions in which heat-sublimable dyes of yellow, cyan, and magenta are successively deposited on a transparent band-shaped base. Printing is performed in yellow, cyan, and magenta sequentially. The density of printing is controlled, for example, by the area of the dots. Since printing starts with yellow, when the print switch is pressed, the ink ribbon 5 is fed until a black stripe-shaped marker provided in front of the yellow area is detected by an optical sensor (not shown). Along with this, platen 1 is a DC motor,
It starts rotating counterclockwise by the driving force of a stepping motor or the like.

Following the positioning of the ink ribbon 5, the photographic paper 2 is fed from a paper feed tray (not shown) while being guided in the direction of arrow A by paper feed guides 11 and 12. At the same time, the thermal head 9 is moved toward the platen 1 side. An optical sensor detects that the end of the photographic paper 2 has reached the platen 1, and from the time of this detection, the position of the front end of the photographic paper 2 is detected from the number of detection pulses generated in synchronization with the rotation of the platen 1.

FIG. 1 shows a state in which the front end of the photographic paper 2 has reached the position of the thermal head 9. As shown in FIG.

Further, as the photographic paper 2 is fed, one end of the photographic paper 2 collides with the back surface near the other end, as shown in FIG. When the platen 1 further rotates from the state shown in FIG.
The wrapped state is fixed. As shown in FIG. 3, when the printing start position near the front end of the overlapping photographic paper 2 reaches the position of the thermal head 9, printing of the first color, yellow, is started.

During printing, the platen 1, photographic paper 2, and ink ribbon 5 rotate together. That is, after the photographic paper 2 is fed, the photographic paper 2 is fast-forwarded one revolution in order to completely overlap both ends of the photographic paper 2, and then the printing operation for the first color, yellow, is started.

The rotational direction and rotational speed of the DC motor that drives the platen 1 are controlled by the system controller according to the operating state. The rotational speed of the platen 10 is varied by switching the drive voltage of the DC motor during the printing operation and during the paper feeding or ejecting operation to the printing start position. For example, when feeding or discharging paper, the platen 1 is rotated at a speed about three times faster than the printing operation. Of course, the platen 1 may be rotated by a stepping motor.

When yellow printing is completed, the thermal head 9 leaves the platen 1, the ink ribbon 5 is wound up by a predetermined amount on the take-up roll 4, and sent to the cyan area. Then, the thermal head 9 is brought into contact with the platen 1, and cyan printing is performed from the same position as the yellow printing start position. When printing of cyan is completed, printing of magenta is similarly performed.

When printing is completed, the photographic paper 2 is moved to the paper ejection guides 13 and 14.
The paper is rapidly forwarded in the direction of arrow B between the paper sheets and delivered to the paper output tray.

A series of printing operations such as rotation of the platen 1, feeding of the ink ribbon 5, positioning of the thermal head 9, and supply of print signals to the thermal head 9 are controlled by a system controller comprised of a microcomputer.

Note that the present invention can be applied to color printers other than video printers, and can also be applied to printing methods other than sublimation thermal transfer methods.

〔Effect of the invention〕

According to this invention, when printing two or more colors in two or more times, the movement of the platen of the photographic paper occurs between the color printed in the first time and the color printed in the second and subsequent times. There is no difference in followability between the two colors, and it is possible to prevent the printing position from being misaligned between these colors.

[Brief explanation of drawings]

FIGS. 1, 2, and 3 are route maps showing an embodiment of the present invention in order of operation. Explanation of main symbols in the drawings 1: Nibraten, 2: Photographic paper, 5: Ink ribbon, 6.7.8: Pinch roller, 9: Thermal head.

Claims (1)

[Claims] A platen whose outer periphery is shorter than the length of the printing paper so that printing is performed with the front edge and rear edge of the printing paper overlapping, and printing on the printing paper. A head and a paper feeding means for feeding the printing paper by sandwiching the printing paper between the head and the platen, and from the start of the paper feeding operation until the front end and the rear end overlap on the platen. A color printer is equipped with means for controlling the printing operation so as not to perform the printing operation.