Incremental printing of symbolic information – Ink jet – Medium and processing means
Reexamination Certificate
2001-06-13
2002-05-14
Gordon, Raquel Y. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Medium and processing means
Reexamination Certificate
active
06386698
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to transfer printing methods, more specifically, to the transfer printing method of printing images by a non-plate electronic print system onto a transfer material using sublimate ink, laying the transfer material ink-side down on top of a print medium, and transferring the print image from the transfer material to the print medium by heat processing the transfer material. The reproducibility of the colors of the transfer material transferred to the print medium is improved by controlling the print density of the yellow sublimate ink on the transfer material within a specific range of yellow density.
BACKGROUND OF THE INVENTION
At present, mainstream transfer printing consists of two methods: the wet transfer method and the dry transfer method. Images are printed first on the transfer material such as paper and plastic film by screen printing or offset printing, then the images are transferred onto the print medium such as glass, metal, plastic or fabric by water, or by heat or pressure, respectively.
However, the above methods require the preparation of a print original for the purpose of screen printing or offset printing, which is time-consuming and costly. It is not suitable for low volume, multiple-type printing, and is impractical in adapting to an ever-changing demand by consumers for new and different designs.
In recent years, it has become very common to sell T-shirts and other merchandise prepared by the following process: Images are printed with a sublimate ink on the transfer material, then such transfer material is used to transfer various images onto T-shirts, aprons, luncheon mats, streamers, stickers, panels, coasters, and the like, by heat-contact printing which sublimates the ink, using an iron. Because of the vast range of consumers' taste and style, which constantly change, there is a demand for low volume, multiple-type printing. This is not compatible with screen printing or off-set printing, which requires the costly and time-consuming preparation of a print original.
In light of such developments, a non-plate electronic print system has been introduced. Images created by digital cameras and scanners, and the like, are inputted to a personal computer (PC) and edited as desired. The images can be printed on the transfer material by an ink jet printer connected to the PC. The images, which are formed of sublimate ink, are then transferred onto the print medium using a heat iron. U.S. Pat. Nos. 5,047,084, 5,684,063, and 5,746,816 disclose such methods.
Such transfer printing using the non-plate electronic printing system permits very easy printing of images onto the transfer material and is suitable for low-volume, multiple-type printing. This method has become popular in recent years since it permits quick changes to meet changing fashion trends.
However, transfer printing using sublimate ink creates a large discrepancy between the colors first printed on the transfer material and those subsequently transferred onto the print medium from the transfer material. The ultimate color of the final images is very difficult to control when printing onto the transfer material. Repeated proof prints are needed to adjust colors prior to printing onto the print medium to provide reproducibility.
Such procedures are acceptable to a certain extent in transfer printing using screen printing or off-set printing, which are based on high volume printing. However, in transfer printing by the non-plate electronic print system for low-volume, multiple type printing, the process has been undesirable due to the disproportionate costs of set-up versus the revenue realized from the job.
It is desirable to increase the reproducibility of the color consistency of the transfers in order to minimize off-color prints prior to the final printing and to minimize the loss of print medium.
The present invention provides a transfer printing method for controlling the reproducibility of the transferred colors, and provides high density, high brilliance transfer prints, minimizing loss through off-color prints.
SUMMARY OF THE PRESENT INVENTION
The present invention relates to the discovery that yellow sublimate ink undergoes little color change during the initial printing stage onto transfer material, as well as after transfer of the image onto print medium. The yellow density is transferred with stability among the three primary colors of red, yellow and blue during printing. It has been discovered that by maintaining the printing density of yellow sublimate ink within a specific range of yellow density during transfer onto transfer material, it is possible to enhance the reproducibility of high density, high brilliance transfer print images on the print medium.
The present invention comprises a transfer printing method which controls the printing density of yellow sublimate ink forming the image on the transfer material within a specific range of yellow density during the transfer print. Sublimate ink is printed onto the transfer material by means of a non-plate electronic printing system. The transfer material is laid on top of the print medium and the image is heat-transferred by sublimation of the ink from the image onto the print medium. The number of correction prints is reduced using the present invention. Reproducible, high density, high brilliance transfer prints are made by adjusting sublimate ink other than the yellow sublimate ink, which functions as the base color, based on images transferred onto the print medium. The yellow sublimate ink is controlled when applied to the transfer material to provide a high density, high brilliance transfer onto the print medium.
Additionally, the invention can prevent ruining the print medium along with ruined transfer material because such transfer material can be discarded when its yellow density of yellow sublimate ink does not fall within a specific range, before printing onto the print medium.
More specifically, it is desirable to control the yellow density on the solid printed area on the transfer material of yellow sublimate ink. Further, it is desirable to control the yellow density of the solid printed area within the range of 0.7-0.9. The density measurement is most accurate when measured on solid printed areas.
It is unlikely to obtain high density, high brilliance transfer prints on the print medium of various types when the yellow density is below 0.7 on the solid printed areas in the transfer material of yellow sublimate ink. Density over 0.9 causes images on the print medium to become blurry and the images themselves to be destroyed. Further, there may be frequent clogging of the nozzle of ink jet printers.
The yellow density described in the present invention means the yellow density measured by a densitometer manufactured based on JIS K 7654 “Photography, Density Measurement Part 4, Geometric Conditions for Reflection Density” (translation of ISO5/4, first edition, published in 1983), i.e. Gretag D 196 (trademarked) by Gretag-Macbeth AG. The print density ratio is the log of the intensity of the reflected light from the yellow density of the solid printed area divided by the intensity of the incident light.
DETAILED DESCRIPTION OF THE INVENTION
Given below is the best mode of execution of the present invention. The present invention is not, however, limited by the following disclosure.
Sublimate Ink
The sublimate ink employed in the present invention is ink containing dyes which sublimate at certain temperatures, in this case, those temperatures achieved by a heating iron. The main components of sublimate inks are dyes, water, solvent and dispersant. Ink jet printer ink may be used.
The sublimate ink may be yellow ink, crimson ink, indigo ink and black ink, and are prepared by mixing the yellow sublimate dye, red sublimate dye and blue sublimate dye in proper proportions (See Table 1 below). In order to expand their range of expression, green, orange, violet and fluorescent ink may also be used.
TABLE 1
yellow dye
red dye
blue dye
yellow ink
□
×
×
cr
Arai Tadao
Miya Eiji
Suga Shoji
Uchida Hideo
Gordon Raquel Y.
Greensfelder Hemker & Gale, P.C.
Megami Ink Mfg. Co., Ltd.
Tran Ly T
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