Color Registration Research Articles

Reinforced Elastomer Roller for Toner Transfer

In commercial electrophotographic copiers and printers, roll fusing, media handling, and toner transfer are technologies that incorporate friction drive with elastomer-coated rollers. When two rollers form a pressure nip and at least one roller is deformable, the surface strain of the deformed roller defines the length of the nip contact area and the speed of the frictionally driven roller. To insure high levels of performance from sub-systems that utilize friction drive, it is important to maintain consistent surface speeds of rollers forming a nip, under a variety of external noises, such as manufacturer tolerances, lack of roller parallelism, media thickness, media tension, and variable toner stack heights. These noises cause variations in surface strains and subsequently surface speeds, adversely impacting image quality, for example, image-to-page registration, color registration, and fusing nip dwell times.For an application that utilizes friction drive for toner transfer, an intermediate image-holding roller has been designed to conform radially with little change in shape circumferentially. The presence of a reinforcing layer just below the surface of an elastomer-coated roller enables sufficient nip contact area for electrostatic toner transfer with minimized drive variations due to external noises. The geometry and material properties of the composite roller is optimized with finite element analysis (FEA). Data from overdrive measurements confirm a reduction in speed variation, and results from a toner transfer experiment show suitable performance for high quality color printing.

Effects of Pretreatments on Print Qualities of Digital Textile Printing

Research presented in this paper addresses some preliminary attempts to establish the relationship between the pretreatment and the digital printing quality by the use of digital image analysis and optical microscopy. As in traditional textile printing, miss color, out of fit patterns, mottle, and color defects due to poor ink surface coverage can occur in digital printing. More specifically, defects in the digital printing of textile fabrics can be categorized into color-related issues (color gamut, color matching, light fastness, wash fastness and uniformity) and appearance-related issues (line definition, dot geometry, penetration, intensity and color registration). Woven and knitted cotton fabrics were treated with twelve formulations including ingredients like alginate, silicone and silica. Printed patterns were analyzed using an optical microscope and a digital image analysis to quantify the print qualities in terms of color-related metrics (L*a*b*) and appearance-related metrics (line width). Results show that digital textile printing quality on cotton fabrics can be optimized with appropriate pretreatments.

３次元映像情報メディア技術 全方向ステレオシステム（ＳＯＳ）のキャリブレーション手法

We have developed a system called the Stereo Omnidirectional System (SOS). The stereo units, which are composed of three cameras, in this system are arranged on each plane of regular icosahedrons. This system can acquire all directional color and stereo pair images, in real time. However calibrating this multi-camera system, which acquires images in different directions from the center of the system, is difficult because simultaneously acquiring images of common regions from multiple cameras is not possible. We described a hybrid calibration method in which the translation parameters use the system design parameters and the rotational parameters are obtained from the images. These adjustments are made because of the difficulty in accurately, obtaining the translation and rotational parameters from the images so that they can be compared. We also described how the color registration method uses common region images acquired from the system.

Stabilized Three-Level Highlight Color Imaging with High Resistance Developer

A one-pass process with combinations of charged and discharged area developments is used for three-level highlight color imaging. The process yields excellent gradation images between black and color because of perfect color registration. However, there are some special problems of fringe images, blurring, and appearance of white spots in the second color images, etc. Employing a very low resistance developer can overcome these problems. As a consequence, though, this type developer results in developing instability due to charge leakage. A highly stable three-level process without these problems is proposed which employs a higher resistance developer without charge leakage and applies a newly developed edge effect control technology and the first color developing station with dual rotation rollers. This process provides excellent highlight color images.

Rotary Deviation of Multi Gear Train Caused by Eccentricity.

The tandem-type color printer has four photo sensitive drums that respectively transfer four colors (Black, Yellow, Cyan, Magenta) to fed papers. One significant factor of the color registration error in this printer is the rotational deviation of the drum. If drums are driven by gears, the transmission deviations of eccentric gears cause the rotational deviations of drums. Therefore, it is important to clarify the transmission behavior of meshing eccentric gears to achieve fine printing quality with colors registered accurately. It has been known that the transmission behavior of an eccentric gear can be approximated by a sine curve. The idea has been applied to analyze the transmission deviation of meshing two eccentric gears. However, no study on the transmission deviation caused by meshing three (or more) eccentric gears has been reported, which is very important from the design viewpoint. In this paper, we formulate the transmiission deviation of a multi eccentric gear system with respect to the amounts of eccentricities and their phases as parameters. We first describe the ratio of rotational velocities of meshing two gears as a reverse ratio of their rotational radii, and solve it as a differential equation of rotational angles. Then, we extend the formulation to a multi eccentric gear systems. Experimental results under practical conditions imply validity of the proposed formulation. For optimum design, we calculate the minimum and maximum transmission deviations with respect to phases of eccentricities in meshing three gears.

Stabilized 3-Level High Light Color Imaging with High Resistance Developer

For the 3-level highlight color imaging, a 1-pass process with combinations of charged and discharged area developments is used. It has an advantage for excellent gradation images between black and color because of perfect color registration. Otherwise, there are some unique problems of fringe images, blur, white spots in the 2nd color images, etc. Employing very low resistance developer gives a solution for these problems. However, this method causes developing instability due to a charge leakage instead.The highly stable 3-level process without the problems, employing the higher resistance developer without the charge leakage and applying newly developed edge effect control technology and the 1st color developing station with dual rotation rollers, are proposed in this study.Finally a stable process and an excellent highlight color image can be provided.

The UV-VIS spectrophotometry applied to color and stability study in colored mortars

In the field of methodologies for color studying, a research of it has been done on colored mortars by applying uv-vis spectrophotometry, instrumental technique which can be used for solid materials works, and previously applied to building materials study. Results obtained show that the mentioned technique permits to evaluate quantitatively and qualitatively colors in an easy and objective way, besides nowadays advantages of the instrumental analysis: digital color register, computerized data processing, and precision and exactness increment in chromatic comparisons.

Multicolor Fluorescent Microspheres as Calibration Standards for Confocal Laser Scanning Microscopy

Reliable image registration is of fundamental importance in confocal laser scanning microscopy. Two types of multicolor fluorescent microsphere standards, each simultaneously stained with multiple dyes, have been developed as calibration standards for confocal systems. These microsphere standards are highly uniform with respect to size and fluorescence intensities and are significantly resistant to environmental factors and photobleaching. Stained with specially selected dye combinations, these beads provide the capacity for testing at the wavelengths commonly used, including the UV and visible spectral lines of argon and krypton ion lasers, and the 543-nm and 633-nm lines of HeNe lasers. Most of the commercial confocal systems collect the selected portions of the emission spectrum that fall within the range of each dichroic filter/bandpass combination. The four-color TetraSpeck beads are ideal for examining the alignment, color registration, and sensitivity. The 6- and 15-μm FocalCheck beads, which are stained with unique fluorescent ring/disk patterns in several multicolor combinations, are particularly useful for assessing the optical-sectioning function.

Color Registration in Press Printing

Color Registration in Press Printing

Color Laser Printer Color Registration by QLPT Mechanism

A small color laser printer using four all-in-one color cartridges and one laser scanning unit (LSU) has been developed. Each color cartridge contains an OPC drum, a charger, a cleaner, and a color developing unit. The cartridges are rotationally switched to produce each color image which is superimposed on an intermediate transfer (IMT) belt. The superimposed full-color image is transferred to paper all at once. The primary feature of this structure is the use of four all-in-one cartridges. It makes color laser printer as easy to use as monochrome ones. When using four OPC drums, each OPC drum has mechanical differences which would normally cause registration errors among colors in conventional mechanisms. The newly developed “QuaLity Positioning Technology” (abbreviated to QLPT) mechanism cancels the registration errors and ensures better image quality. The QLPT mechanism consists of three points, which are1) Holding and locating mechanism;2) Solid coupling and synchronizing mechanism;3) Slipping correction mechanism.The essence of the QLPT mechanism is described below.

Color Registration for Serial Type Thermal Transfer Printer

Color Registration for Serial Type Thermal Transfer Printer

Machine Optimizing Technologies for Color Registration of Electrophotography

Machine Optimizing Technologies for Color Registration of Electrophotography

TonerJet® Tandem Color has Reached Prototype Stage

The TonerJet® print technology is invented and developed by Array Printers AB in Sweden. During the last years, the TonerJet® print process have taken some big steps forward in color printing.A focus on toner development at the TonerJet® Center in Yokohama, Japan, has been fruitful. The speed and performance of the print process have improved when implementing a chemical toner. The spherical shaped particles enables higher density and edge sharpness at higher print speed (10-20ppm). This is a result of the increased release properties at higher toner charge.TonerJet® is a direct print process that easily achieves extremely good and stable color registration at low manufacturing cost. The dot registration can be controlled by a feedback loop that measures the print media position.Pulse width modulation enables true gray scale printing down to few particles per dot. This in combination with the dot deflection control technology gives high image print quality.TonerJet® is now the print technology that combines color printing at a high speed, good print quality and a low manufacturing cost.

Model-based halftoning of color images

We present a new class of models for color printers. They form the basis for model-based techniques that exploit the characteristics of the printer and the human visual system to maximize the quality of the printed images. We present two model-based techniques, the modified error diffusion (MED) algorithm and the least-squares model-based (LSMB) algorithm. Both techniques are extensions of the gray-scale model-based techniques and produce images with high spatial resolution and visually pleasant textures. We also examine the use of printer models for designing blue-noise screens. The printer models cam account for a variety of printer characteristics. We propose a specific printer model that accounts for overlap between neighboring dots of ink and the spectral absorption properties of the inks. We show that when we assume a simple "one-minus-RGB" relationship between the red, green, and blue image specification and the corresponding cyan, magenta, and yellow inks, the algorithms are separable. Otherwise, the algorithms are not separable and the modified error diffusion may be unstable, The experimental results consider the separable algorithms that produce high-quality images for applications where the exact colorimetric reproduction of color is not necessary. They are computationally simple and robust to errors in color registration, but the colors are device dependent.

Image Quality Metrics for Printers/Plotters

Today, non-impact printers have become a common office peripheral. With this increase in market acceptance, the understanding of computer imaging has left the realm of black magic, known only by a select group of scientists and engineers, and entered into the mainstream of computer literacy.Competitive bench marking articles in popular computer magazines no longer look at just the price of the printer, how clear the user manual describes using the software that comes with it and if the manufacturer's technical support department picks up the phone. They are beginning to look inside the device at the optical, mechanical and electronic precision as measured by output image quality.Today, manufacturers are beginning to use sophisticated machine vision software technology to evaluate image quality and set the standards for their design and manufacturing operations. Their marketing organizations are using the same technology to perform competitive analysis.Manufacturers of printers need to understand how this new technology is being applied to assure competitiveness, improve customer satisfaction and to be able to respond to the growing awareness and expectations in the marketplace regarding image quality standards.This paper will present a series of specific metrics for quantifying image quality for non-impact printers. Specific metrics will include Color registration, Color consistency, MTF, resolution, Streak noise, Text quality, Motion quality, Linearity, Sharpness, Smearing effects, Dot quality and others. Discussion will also present methods by which manufactures have achieved a fully automatic image quality testing process. Case studies and examples of current installations at major printer manufacturers will be discussed.

From false starts to firm beginnings: Early colour printing of geological maps

Abstract Geological information was first printed in colour on a map in 1820 but serious efforts to print geological maps in multiple colours began in Europe only in the 1840s. Increased geological mapping activity created the need to print more maps by cheaper methods, while general advances in lithographic colour printing provided the means. Better colour registration, transparency, range, permanence and distinctiveness were attained in the 1840s and 1850s by technical innovations and also by new design strategies. Consequently, as printed colour replaced hand colour as the norm, it also influenced the look of the geological map.

An Advanced High-Resolution, High-Brightness LCD Color Video Projector

A liquid crystal device (LCD) projector has been developed that yields bright, high-resolution color television pictures on screens as large as 120 in., diagonally measured. It possesses a compact, single-lens optical system in which color registration, or convergence, is permanently established and set during manufacturing. The user may therefore relocate the projector and change the projected image size at will, and without the necessity to perform color convergence adjustments afterward. Anamorphic lenses have been developed that permit this to project “wide-screen” pictures with an aspect ratio of 16:9, in addition to normal lenses that yield a standard television picture of 4:3 aspect ratio. Anamorphic lenses have been developed as well for television cameras so that the widescreen pictures can be acquired by conventional NTSC color cameras and recorded with standard NTSC-format videocassette recorders.

Television Zoom Lens with Three Integrated Zoom Ranges

After discussion of the demand for a lightweight zoom lens for color television, the design and mode of operation of an optical system with variable focal length incorporating three integrated zoom ranges is described and solutions to the optical problems for cameras using microprocessors with automatic adjustment of contrast, geometry, linearity, and color registration are shown.

Vision with isoluminant colour contrast: 1.A projection technique and observations.

An optical technique is described for projecting two-colour pictures with controlled brightness contrast, which may be set to zero-at isoluminance. Colour registration is maintained without adjustment or special setting up. It is suggested that colour-and brightness-contour registration in the visual channel is a problem which may be solved neurally be master brightness signals locking slave colour signals. The projection apparatus allows the supposed master brightness signals to be removed-at isoluminance-when contour disturbances should occur. Observation of this kind are reported.

The cholophor: A passive polarization-switched liquid crystal screen for multicolor laser displays

Cholophors are passive polarization-switched color display elements suitable for use with lasers or white light. Their hybrid structure, consisting of a thin layer of cholesteric liquid crystal over a layer of photoluminescent phosphor, provides properties of particular interest for large-screen optically scanned multicolor display applications. Cholophors permit more efficient use of available laser power while providing a solution to the problem of color registration for two-primary displays and a partial solution for three-primary displays. Two-primary or Land-color displays can be obtained with only one color of laser light and three-primary displays with only two colors. A three-primary cholophor display using a single argon ion laser would have over 7 times the efficiency of a typical state-of-the-art system using an argon-krypton mixed-gas laser. The liquid crystal layer provides polarization selectivity, and the phosphor layer produces the additional color not furnished by the laser. The liquid crystal transmits one sense of laser polarization while totally reflecting the other, thereby permitting polarization selective excitation of the underlying phosphor. The color selection information is coded into the polarization of the incident laser beam.