Magnetic recording on a visual image developed by magnetic toner is tried so as to find out the possibility of recording voice and digital data. For comparison with normal magnetic tape, the paper with a toner image is cut to form a 6 mm width tape and set on a deck for open reel tape.
When ordinarily processed, playback output signal by a toner tape is about 40 dB smaller than the signal by a normal magnetic tape. But, by heating to fuse toner particles and by applying magnetic field to orient the magnetic direction of magnetic particles in a toner, the playback output signal becomes larger by 10~20 dB. And the analog signal to 3kHz including manual voice are played back with a noise of 30~40 dB smaller than the signal. And digital data of 25 bit/mm are played back by the speed of 9.5 cm/s ( =2400 baud) and character data in RS232C code are received by computer without any errors. These results show messages or character date can be densely recorded on the toner image of normal toner density.

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A model describing the charging behavior of Xerographic double component developers is presented and examined experimentally.
The model assumes two concurrent processes taking place at the interface between the toner and the carrier surface. One is charge generation, expressed in terms of the work function difference (φ_TN-φ_CR), the other charge leakage, expressed in terms of a proportional function of tribo charge value (q) with a characteristic time constant (τ).
The model, which fits the actual dependence of tribo charge on mixing time, leads to the hypothesis that the saturated tribo charge (q_max) is related not only to (φ_TN-φ_CR) in the charge generation process but also to τ in the charge leakage process, which is further related to toner dielectric properties.
In order to test the hypothesis, an experiment was carried out, Toners with three different carbon blacks of varying loading and of a varying degree of melt-mixing in Styrene-Acrylic copolymer were prepared, and three tribo charging properties (q_max, τ and polarity), the work function of the carbon blacks and the dielectric properties were determined.
The following conclusions were derived :
(1) q_max increases with τ, which is consistent with the model, for toners of different carbon black loading and the same processing conditions, and for toners of the same formulation under different melt-mixing conditions.
(2) The triboelectric-series of experimental toners as determined by q_max are consistent with the order of measured work functions of the carbon blacks tested.
(3) Since q_max depends linearly on τ which is in turn proportional to the reciprocal of tan δ, q_max is proportional to the reciprocal of tan δ, again, as predicted by the model.
Thus, the model can explain the tribo charging behavior of toners which contain carbon blacks of varying degrees of melt-mixing.

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Utilization of multilayered photoreceptors is shown to serve for the determination of transit time of carrier packet in organic carrier-transport materials by time-of flight (TOF) and xerographic time-of-flight (XTOF) techniques. The structure of the photoreceptors consists of carriergeneration layer, carrier-transport layer (OPC) and, in addition, current-amplification layer. By using them, hole transit photocurrent pulses obtained by the TOF techniques are characterized by a maximum following after a minimum, influenced by the spreading of the carrier packet travelling in the transport layer. Times when the minimum and the maximum appear on the photocurrent pulses are shown to correspond with the time for the front edge and the peak density portion of the carrier packet to arrive at the interface between the carrier-transport layer and the current amplification layer, respectively. On the other hand, surface potential discharge rate by the XTOF technique becomes fast suddenly at a time after the exposure of light flash. Time dependence of its rate is discussed, and it is shown that the transit times of both the front edge and the peak density portion of carrier packet across an OPC layer are deduced. Drift mobilities in poly-vynylcarbazole layers from our experiments are compared with them given by other investigators, using twolayered photoreceptors.

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The laser printer offers the advantages of high-resolution output at high speeds, and is widely utilized as an output device for vffice automation equipment. In conjunction with the recent popularization of desktop publishing systems based on personal computers, there has been a growing demand for laser printers which offer higher quality imaging.
At this time, the authors have developed a high-resolution laser printer for the purpose of fine image reproduction, which combines newly developed high-resolution toning system and semiconductor laser recording technique.
This printer has the following features :
(1) Print density of 600 dots per inch.
(2) Printing speed of 10 letter-sized sheets per minute.
(3) Capable of using paper of a maximum B4 size.
This printer provides high-quality image printing, and is ideally suited to serve as the output device for desktop publishing systems and in-house typographic printing systems.

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This review discusses the state-of-the-art status of high resolution ink jet printers. It is argued that among the nonimpact printers, the ink jet printers are best suited for high resolution printing.
Among the ink jet printings, Drop-on-demand ink jet printing is coming up fast and may soon prevail the market of inexpensive multicolor printers, because of its practical combination of reasonable cost and performance. With further development to increase reliability and cut manufacturing cost the continuous-jet printer, especially the Herz method and/or the microdot method ink jet printer, should have no rival for depicting large amounts of information with near photographic resolution.
Other important aspects biefly mentioned in designing color printers are the more difficult task of formulating inks and associated paper with suitable chromatic and archival characteristics.

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Sublimation Transfer material is the most suitable for high quality color image recording among Non-impact printing technologies and materials. The advantage of Sublimation Transfer material to others consists in its 1) easy control of gradiation, 2) good reproducibility of print out density, 3) smooth gradation change in high light region, 4) high density print out and 5) high resolution.
In this paper, characteristics of Sublimation Transfer material and Degital Color printer for color proofing in prepress process are explained. And vital points for high quality image reproduction are explained.

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