In the color conversion processing for HiFi-Color, it was an issue to realize colorimetric color reproduction, continuousness of color separation and adjustment of K/RGB. This paper describes a new color conversion method to realize colorimetric color reproduction, continuousness of color separation and adjustment of K/RGB. The new color conversion algorithm proposed in this paper consists of these 3 steps as follows, (1) setting UCR rates of K/RGB by function of L*a*b* color signals, (2) calculating K/RGB signals by L*a*b* color signals and UCR rates of K/RGB, (3) calculating YMC signals by L*a*b* color signals and K/RGB signals. This algorithm realized colorimetric color reproduction, continuousness of color separation and adjustment of K/RGB.
The Image-on Image (IOI) color process,in which color images are superimposed on a single photoreceptor and then transferred to the paper at once,possesses capabilities for realizing a high speed,high quality, and compact color printer. However,in the IOI processes using dry toners,there are unavoidable problems that make it difficult to obtain high quality color images. TOSHIBA found that,using liquid toners,these issues are completely resolved and high quality color images comparable to offset prints are realized. In this paper, liquid toner IOI process is proved to be an excellent color process by comparing development characteristics and color image qualities between IOI processes using liquid and dry and liquid toners. The results of theoretical analyses agree with these experimental data. Furthermore, two kinds of prototype printing machines using liquid toner IOI process are introduced.
The development process of liquid toner to reproduce 2540dpi single-dot images was investigated using numerical simulations taking account of the motion of both toner particles and counter ions. The simulation shows that, at an early stage of the development, the toner particles are developed around the edge of the latent image on the photoreceptor, and then the particles are accumulated to form a single dot with horizontal migration toward the center of the latent image. Such developing behavior is characteristic of liquid toner, and the result suggests the mechanism of the high reproducibility of liquid development. In addition, the development-bias dependence of dot diameters agrees well with the experimental results and the validity of the model was confirmed. Moreover, the capability of high-resolution multi-line pattern formation was investigated by theoretical analysis using the same model as that for the single-dot analysis. As a result, a phenomenon peculiar to the multi-line pattern was found and the guideline to the higherresolution image was obtained. Thus,the superiority of the liquid toner process that can reproduce a singledot whose diameter is less than 10 μm and a multi-line image consisting of lines of 10 μm wide was clarified by both the theoretical and the experimental analyses.
Extremely high-resolution images have been obtained by an electrophotographic imaging system using liquid toner. This system includes a high-resolution Laser Scanning Unit (LSU) with a 2540dpi resolution, and an image transfer system that does not use electrical energy. We examined the characteristics of highresolution image creation,in particular the relationship with laser beam focusing and laser power to obtain the optimized parameter value of the LSU. The image pattern from this system was confirmed to be accurate according to the resolution. Furthermore, an examination of the noiseless transferability of “shearing transfer” showed the accuracy of the created image was due not only to the development process, but also to the transfer process. We attempted to print a full-color image with this system, and obtained a real 2540dpi color image, which is equal in quality to that produced by offset printing.
The motion of the particles made of several kinds of materials between voltage applied electrodes is observed by a high speed camera. The motions are classified to three categories such as cyclic up and down motion, cyclic motion accompanying bounding, and motion with obvious staying at electrode. The classification is considered reasonably from the view point of the ratio of contacting time to electric relaxation time. The charge amount of the metal particle is estimated from the motion to be approximately saturation charge value induced by the external electric field.
Relationship between pre-printing and post-printing topographies of paper surfaces in both electrophotography and offset printing was discussed. The correlation coefficient of Pearson between two-dimensional profiles of paper surface and its printed surface at the same location was calculated by using four kinds of coated paper of different gloss. The correlation coefficient was high for every coated paper except cast coated paper for offset printing.,but it was low for every coated paper for electrophotography. Even rough low-gloss paper resulted in a low correlation coefficient, therefore paper surface profile does not influence printed surface profile greatly for electrophotography. Then, transfer function analysis was applied to surface profiles as paper surface profiles were input and printed surface profiles were output. Two differences were found between the two printing methods. One is the printed surface topography formed by toners or inks at lower frequencies. The other is the level to which roughness of paper surface is filled by toners or inks at higher frequencies. Moreover,for electrophotography,reduction in amount of toners gives a better correlation coefficient between paper surface and printed surface profiles.
Outline of thermally stimulated current (TSC) spectroscopy was briefly described and then applications of the TSC method to film -and powder-formed polymeric samples were introduced: For film-formed spherulitic polypropylene samples, charge trap sites of them were connected with the molecular aggregation states of the polymer by making combined use of the TSC method and another techniques such as thermal cleaning of the trapped charges and visualization of the charged areas. For charge control agent (CCA)-containing powders of a binder resin for toners, TSC method was also applied to them to clarify the role of the CCA for frictional electrification against carriers. From observed TSC spectra, one of the CCAs used in this study was clearly demonstrated to have its own peculiar charge traps, while the other did not seem to have charge traps for itself.
We have developed an ultra high-speed video camera. This new camera can capture 100 consecutive images with a frame rate up to 1,000,000frames per second (fps). It comprises a new developed single-chip CCD image sensor called IS-CCD. The spatial resolution is about 81,000pixels and this high resolution is kept even at the maximum frame rate. We described about the high-speed video camera HPV-1and several kinds of high-speed photography with the HPV-1.
Accompanying with increase of surfaces, of which appearance changes with observing direction, the importance of goniometric spectrocolorimetry is increasing. Spatial and spectral distribution characteristics of reflected or transmitted light are fundamental optical properties,which relate not only flip-flop color, but also surface appearance. These optical properties are measurable by goniometric spectrocolorimetetry, and used for data-base of three dimensional image in computer graphics, which gives not only shape and color but also more realistic appearance. This guide gives basic knowledge for measuring principle, reference of measurement and geometric conditions, by which the relations between spatial and spectral distribution characteristics of reflected or transmitted light from the surface and measured value by goniometric spectrocolorimetry would be understood. As examples of gonio-spectrophotometric color measurement system, Model GCMS-3B, for general use, Model GCMS-11, for sophisticated usage and Model DV-10, for visual inspection are introduced.
As fundamental knowledge of color expressions and color measurement necessary when handling the information of color images,the color perception mechanism of humans and the basics of the corresponding CIE color spaces will be introduced,and the structure of color-measuring instruments and how they put color theory into practice will be examined. Further,we will also describe how,in contrast to the various ways in which colors change depending on the viewing conditions, color measuring instruments are able to accurately obtain color information by regulating viewing conditions, and also touch upon the causes of color-measurement error which are closely related to viewing conditions. Finally, we will introduce a two-dimensional color-measuring instrument, which is expected to be used in the image information field.
In recent years, there has been a focus on non-contact 3D measurement equipment in various industrial fields. We will present an outline of non-contact 3D measurement equipment through the introduction of Konica Minolta Sensing, Inc.'s VIVID 9i. Measurement of a wide or the entire area of a target object is made possible by allowing the merging of separate measurements of plural object sections. Data processing technology for data alignment is required to obtain 3D data for the entire object. 3D data processing technology consists of technology for polygon creation, noise reduction, data alignment, data merging, and data correction. We will also present modeling, RE (Reverse engineering) and CAT (Computer-assisted testing) as examples of the use of these techniques in the fields of production and manufacturing.
While color and density have been synonymous with print quality for a long time,the importance of other print quality attributes such as sharpness and details,and printing artifacts such as bleed, edge acuity, banding, and gloss non-uniformity can hardly be overemphasized. The growing recognition of the importance of such “non-color and density” attributes has been partly driven by the introduction of many digital printing processes that exacerbate such print quality (PQ) problems. To advance digital printing technology and to solve PQ problems,a necessary first step is to objectively quantify the critical print quality attributes beyond density and color, hence creating a demand for new tools other than the familiar densitometer or spectrophotometer. Responding to this need, image analyzers have been developed in parallel with the development of the digital printing industry over the last two decades. The early image analyzers were typically large tabletop units that were often installed in a central laboratory and required the support of a specialist. Bringing the technology of PQ analysis to a much broader community of users, a handheld image analyzer called the Personal IAS was introduced by QEA in 2001. This batterypowered, portable instrument makes it possible for the first time to make objective print quality measurements anywhere,including in the field and on the production line. This paper describes the design of the instrument and demonstrates its capabilities by means of a series of practical applications in digital printing.