A solid imaging ink-coated sheet for use in photoelectrophoretic imaging systems comprising a support substrate having adhered to a surface thereof a thin, solid layer of an imaging ink suspension. The imaging ink suspension comprises a plurality of photosensitive pigment particles and thixotropic additive particles dispersed in a carrier liquid.

A composition capable of forming colored complexes with transition metal salts is provided which comprises an aromatic substituted hydrazone carried in an organic cosolvent vehicle. When employed in the art of carbonless paper the aromatic substituted hydrazone and the transition metal salt complex to form yellow colored images. The invention provides means for producing dark, black, neutral images by the reaction of the aromatic substituted hydrazones and conventional dithiooxamide complexing c...

A document drum and a transparent drum are mounted on a common shaft. The two drums are coaxial with each other and with the shaft. An optical system is provided for forming an image of a slit-like rectangular area of a document mounted on the external surface of the document drum onto a similar slit-like imaging area on the imaging drum. The optical system comprises a first mirror for reflecting light rays from the document drum to a lens, and second and third mirrors for reflecting light rays ...

Nuclear magnetic resonance (NMR) apparatuses have been proposed to examine slices or volumes of bodies, perhaps patients for medical purposes, by exciting resonance and detecting the resonance signals. In an NMR apparatus an G.sub.R field gradient, for selecting lines within a slice or volume, is formed of Gx and Gy components. These should match exactly in shape if not in magnitude. In practice this is difficult to achieve and it is proposed to monitor these fields and derive error signals for ...

In a medical NMR apparatus it is desirable that the axial magnetic field, Ho, is uniform. The result can in theory be obtained by accuracy of construction but in practice this cannot readily be achieved. It is now proposed to use a field sensing probe system which indicates the value of that field at a plurality of positions in the examined region and provides error signals indicating deviations from uniformity. The field is automatically corrected in response to the error signals by applying cu...

In a nuclear magnetic resonance imaging apparatus it has been proposed to excite resonance preferentially in a cross-sectional slice of a patient's body by applying a field gradient pulse in conjunction with a pulse of RF. It has been found that the shape of the RF pulse envelope can be chosen to reduce excitation outside the chosen slice. It is proposed that the RF envelope should be a unidirectional pulse of which both the rising and falling parts are monotonic curves lying between limits give...

Dry-process imaging apparatus for flash imaging an imaging film having a layer of an energy dispersible image forming material on a surface thereof. The apparatus comprises a source of electromagnetic or radiant energy, radiant energy collecting and guiding means, and support means including masking means for the imaging film. The apparatus is especially suitable for flash imaging microfiche cards, and enables an imaging energy source such as, for example, a Xenon flash tube, to be operated at l...

An electrostatographic developer mixture comprising finely-divided positively charging toner particles electrostatically clinging to negatively charging carrier particles. The toner particles comprise a resin, a colorant, and a charge inducing material selected from (1) a long chain hydrazinium compound and (2) an alkyl pyridinium compound. The carrier particles comprise core particles having a coating of fused thermoplastic resin particles wherein the carrier particles are prepared by dry-mixin...

Nuclear magnetic resonance (NMR) apparatus have beenproposed for examining slices or volumes of bodies, perhaps for medical examination of patients. Magnetic fields are used to induce resonance in a selected region of a body and a resonance signal is detected during a pulse of a gradient field which causes phase dispersion across the region. It is now proposed that more efficient operation of the apparatus is possible if the gradient pulse is a non-square pulse, perhaps a distorted sinusoid, and...

In an imaging apparatus using nuclear magnetic resonance, first and second gradient field pulses are applied, the second being of opposite sense to the first. It is preferable to match these so that they entirely cancel. However it is shown to be sufficient if they are as close as possible to the same magnitude and a further `glitch` pulse is used to reduce the total gradient field over the pulse sequence substantially to zero.