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Colour video printer technology has changed relatively little in the past five years but now Mitsubishi have taken a big step forward with the recently launched CP700, which combines high performance, low operating costs and super-fast printing speed with an amazing 200-print capacity



The seemingly straightforward task of getting a video image onto paper -- making a hard copy from a camera or VTR source  -- has proved to be a formidable technical challenge. Basically there are three ways of doing it. The oldest, simplest and cheapest method is to photograph a video screen. Alternatively video images can be  downloaded into a computer and committed to paper using a high-quality colour printer. However, the easiest and most cost-effective solution is a dedicated video printer, like the Mitsubishi CP700E we're looking at here, but more about that in a moment.


Off-screen photography has the potential to give the highest image quality, yet it is fraught with difficulties. Specially-designed CRT cameras are available, however, unless the system uses a Polaroid instant camera there's an inevitable delay in getting the film processed.  Using a computer to produce hard copies is the sledgehammer approach. The equipment is expensive, and at the current stage of development image quality is marginal, but there is considerable room for improvement and it could become viable in the not too distant future. For the moment at least dedicated video printers remain the most flexible and cost-effective option.


There are basically two types of video printers, for monochrome or colour work. Black and white models use a thermal paper printing system, similar in principle to the way fax machines work. The most recent ones work quite well, and they're relatively cheap to run, but images tend to have a fairly narrow contrast range, resolution can be quite coarse and prints fade quite quickly. Furthermore, as more CCTV systems use colour cameras they will become increasingly marginalised.


Colour printers, like the CP700, employ a process known as dye-sublimation, which also relies on thermal printing techniques. The results can be excellent -- advanced models are capable of photographic quality -- but they are expensive, so too are the consumables, prints typically cost as from 70 pence upwards. 


Print costs on the Mitsubishi CP700 are substantially lower than that, they actually work out at about 40 pence each. That's largely due to an ingenious printing mechanism that uses a continuous roll of printing paper -- a world first on this class of equipment -- instead of the more usual cartridge containing separate sheets. Each roll of A6-sized paper can produce up to 200 standard (S-size) prints  measuring 110 x 107 mm, or  125 large (L-size) prints measuring 162 x 110 mm, depending on the type of ink-sheet used.


Maximum resolution at 1216 x 600 dots is significantly higher than most existing colour video printers;  it can render up to 256 gradations with a theoretical range of 16.7 colour shades. Print density is 300 dots per inch (dpi), that too is a vast improvement on current colour printers, (most other models are in the 150-200 dpi range). Standard sized prints take just over 20 seconds to emerge, the current norm is a little over a minute per print!


It's compact too. Most other colour video printers are about the same size as a time-lapse video recorder, yet this one is considerably narrower, measuring just 280mm wide. It's quite tall at 150mm but only 399 mm deep. It is very heavy though, weighing in at a substantial 14.5 kgs. The printer mechanism takes up most of the width of the front panel, it slides out from the front of the machine for loading. The roll clips into a carrier at the rear of the tray, and has to be threaded through a series of rollers to emerge through a slot in the front panel. The ink sheet is supplied as two rolls of coloured film, alternately yellow, magenta and cyan. The rolls are inserted into a re-useable cartridge that slots into a cavity on the side of the mechanism. With practice changing rolls takes no more than minute or so.


On the front panel there's an LCD status/mode display and just five controls. They are for switching the machine on and off, the printer tray lock, and three buttons for selecting the monitor output, storing an image and printing. Everything else is controlled from a wired remote control box, that plugs into a socket on the front panel.  All of the input and output connections are on the rear panel. They comprise composite and S-Video inputs and outputs (mini DIN and BNC), and two banks of BNC sockets for analogue RGB inputs and outputs. Additionally there's a 25-pin D-socket for an RS-232 serial link to a PC or controller, a second remote control socket and a standard IEC mains supply socket.


Once the paper has been loaded the only preliminaries are to set the time and date using the first of two menu display systems. The clock set options are on the 'SW' menu, which is engaged by holding down the memory buttons whilst switching the printer on. The relevant data appears on the LCD screen but it's easier to make adjustments using the on-screen display. Menu selections are made using a set of four cursor keys on the remote handset, and stored or changed with the menu and set buttons. Other options on the SW menu include setting the main input and output signal parameters (it can operate with mixed inputs and outputs; for example, S-Video in, RGB out to monitor), print speed, direction, sheet cutting, print density and setting up the RS-232 command link with an external controller.


The 'Main' menu can be called up at any time, this covers all of the printers numerous secondary functions via six sub-menus. The first one is for adjusting brightness, colour and contrast, for both the finished print, and the monitor display. Number two selects the video input signal format, normal or reverse field selection, AGC, AFC and DCF settings. The AFC function acts as a timebase corrector, stabilising images from noisy or worn recordings. Sub menu 3 deals with additional functions including strobe speed (for creating multiple images), multiple image printing/display (1, 2, 4 or 16 pictures), print orientation and whether or not multiple images are separated by white borders. Sub menu 4 is for selecting paper size, gamma curve adjustment (normal, deep and echo -- for medical equipment), image outline or sharpness (4 levels), selecting the type of data or information printed beneath the image, and mirror-image printing, where the picture is effectively printed back to front. The fifth sub-menu is concerned with composing titles or 'comments' on the finished print. The last sub menu deals with image size, print density, page number printing, monitor output display, output signal conversion, and audible buzzer on/off.


This all sounds reasonably straightforward but the on-screen display and control system are this printer's most obvious weakness. It's incredibly difficult to get to grips with and it's compounded by impenetrable instructions. To be fair the information is there -- probably -- but finding it is an absolute nightmare, and even an apparently simple operation, like displaying the multi-print format on the monitor screen, is almost impossible to find. The instructions for setting up the 'comment' display occupy no less than six pages! The problem is almost certainly rooted in the translation from the Japanese; both the operating software and the manual could do with a major overhaul. We suspect Mitsubishi will be getting a few calls about this one...


Making sense of the various print options takes some doing but it's worth persevering as it's one of the machines major selling points. The strobe function allows images to be stored in the 4.4 megabyte frame-store memory at selected intervals of 1/13, 1/5, 1/2.5 th sec, 1, 2, 5, 10, 30 seconds, 12, 5, 10 and 30 minute intervals. After each acquisition the image is automatically printed. The multi-picture functions are equally impressive, the basic options are for 1, 2, 4 or 16 images per print; these can all be the same, or different, as part of a stored sequence. A third option, 'photo' orientates the print to a portrait layout, with the smallest images printed as 1.5 x 2cm blocks, suitable for use on photo identity cards. In the 4-image mode each picture measures 3 x 4 cm, and 2 image prints measure 5cm square.


The comment printing function can insert a line of up to 48 alphanumeric characters below the printed image. There are four options: a user-composed title; user title with time and date; colour adjustment data showing colour, contrast and brightness settings, and a data mode, detailing the total number of prints, signal configuration settings and print position data.


The large frame store memory is used in a variety of ways. In the 'frame' mode it records two images, or four in the field mode. Frame mode gives the highest image quality but any movement in the picture will produce a jitter, due to the difference between the two fields. In multi-print mode the memory can store four images per page (frame setting) and eight or sixteen images with the field setting. Images are stored sequentially by pressing the memory button. Once an image has been stored any necessary picture adjustments can be made, to compensate for lighting conditions and small exposure errors.


Printing is initiated by pressing the print button. The paper emerges briefly from the slot on the front panel as the sheet makes the first of three passes beneath the ink film and print head. Progress is shown on the on-screen display.  Finally the print emerges and a paper cutter separates it from the roll. Normally this takes around 25 seconds, selecting the higher print speed results in slightly lighter colours.



We ran a series of resolution tests on the printer, using both composite and S-Video inputs from a high-band colour camera. Not surprisingly the best results were obtained using an S-Video input, in frame mode. The printer was able to resolve in excess of 450-lines on an S-size print, from a standard video test chart. This fell to just under 400-lines using a composite video feed. There was only a small drop in resolution in the field modes, though colours looked a little fuzzy and there was a slight increase in granularity. Colour fidelity is generally very good, though obviously much depends on the source signal, but our sample clearly favoured strong reds and blues, greens are slightly muted, though there is plenty of scope to adjust the overall colour balance.


One small point about the finished prints. The paper is very thin; a combination of the glossy surface and static electricity makes them stick to one another and difficult to separate. This seems to wear off after about 24 hours and they become easier to handle. Mitsubishi tell us they will be introducing a slightly thicker paper in the near future, though this will reduce the number of prints from each roll. 



Our only misgivings concern the awkward control system and poorly presented instructions. Mitsubishi are justly proud of the CP700, it is a remarkable piece of equipment, capable of outstanding results. Operating costs are up to half as much as comparable printers, it's twice as quick and the end-user price of 2450 seems entirely reasonable.



Dye sublimation is the most successful 'dry' colour printing system so far and is easily integrated with video imaging systems. The process is reasonably simple. The stored image is broken down into component colours, in this case the compliments (reverse colours) of red, green and blue, which are cyan, magenta and yellow. The print paper and ink sheet are brought together beneath a thermal printing head, covered in microscopic heating elements. When each one is switched a tiny dot of coloured dye is transferred from the ink sheet to the paper. The print paper makes three passes beneath the head, with the ink sheet wound to the next colour in the sequence for each pass, until the colour image has been built up. The tiny dots that make up the image are only just visible under a powerful magnifying glass. Various digital signal processing techniques are employed to remove any traces of line structure or digital artefacts from the image, resulting in a near-photographic quality picture.




Mitsubishi CP700E Colour Video Printer, 2450


System             dye sublimation

Max resolution            1216 x 600 dots

Colour gradation            256 per colour

Print speed                    22 - 29 sec (S-size), 38 - 51 secs (L-size)

Print paper size            162 x 110 mm (L), 110 x 107 mm (S)

Print options                  frame or field mode, multi-prints, photo, strobe                

Print formats             1, 2, 4 or 16 images per print

Video Inputs                  composite, S-Video, RGB analogue

Video Outputs            composite, S-Video, RGB analogue

I/O Terminal                   RS-232 interface

Power   Supply            220-240 VAC 50Hz

Power Consumption            160 watts whilst printing



CK700 printing paper    30.00 (200 S-size or 125 L-size prints)

PK700S S-size ink sheet             47.00 (200 prints)

PK700L L-size ink sheet            47.00 (125 prints)



Dimensions                   280 x 150 x 399 mm  

Weight              14.5kg 





Product             9

Product design            7

Build quality                  9

Ruggedness                  9



General functions            8                     

Ease of use                   6

Instructions                   5

Manuf. support            9                     



Resolution                     9

Colour fidelity            9




( R. Maybury 1996 1602









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