Plotter

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Hewlett-Packard A0 Plotter 5785B

The plotter is a computer printer for printing vector graphics. Plotters draw pictures on paper using a pen. In the past, plotters were used in applications such as computer-aided design, as they were able to produce line drawings much faster and of a higher quality than contemporary conventional printers, and small desktop plotters were often used for business graphics. Although they retained a niche for producing very large drawings for many years, plotters have now largely been replaced by wide-format conventional printers.

A computer is a device that can be instructed to carry out sequences of arithmetic or logical operations automatically via computer programming. Modern computers have the ability to follow generalized sets of operations, called programs. These programs enable computers to perform an extremely wide range of tasks. A "complete" computer including the hardware, the operating system, and peripheral equipment required and used for "full" operation can be referred to as a computer system. This term may as well be used for a group of computers that are connected and work together, in particular a computer network or computer cluster.

Vector graphics type of 2D digital illustration that uses geometric and styling definitions to represent images

Vector graphics are computer graphics images that are defined in terms of 2D points, which are connected by lines and curves to form polygons and other shapes. Each of these points has a definite position on the x- and y-axis of the work plane and determines the direction of the path; further, each path may have various properties including values for stroke color, shape, curve, thickness, and fill. Vector graphics are commonly found today in the SVG, EPS and PDF graphic file formats and are intrinsically different from the more common raster graphics file formats of JPEG, PNG, APNG, GIF, and MPEG4.

Computer-aided design constructing a product by means of computer

Computer-aided design (CAD) is the use of computers to aid in the creation, modification, analysis, or optimization of a design. CAD software is used to increase the productivity of the designer, improve the quality of design, improve communications through documentation, and to create a database for manufacturing. CAD output is often in the form of electronic files for print, machining, or other manufacturing operations. The term CADD is also used.

Contents

Overview

Digitally controlled plotters evolved from earlier fully analog XY-writers used as output devices for measurement instruments and analog computers.

Analog computer computer using continuously changeable aspects of physical phenomena (electrical, mechanical, hydraulic, etc.) to model problems, behavior of other physical system, or mathematical function

An analog computer or analogue computer is a type of computer that uses the continuously changeable aspects of physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved. In contrast, digital computers represent varying quantities symbolically, as their numerical values change. As an analog computer does not use discrete values, but rather continuous values, processes cannot be reliably repeated with exact equivalence, as they can with Turing machines. Unlike machines used for digital signal processing, analog computers do not suffer from the discrete error caused by quantization noise. Instead, results from analog computers are subject to continuous error caused by electronic noise.

Pen plotters print by moving a pen or other instrument across the surface of a piece of paper. This means that plotters are vector graphics devices, rather than raster graphics as with other printers. Pen plotters can draw complex line art, including text, but do so slowly because of the mechanical movement of the pens. They are often incapable of efficiently creating a solid region of color, but can hatch an area by drawing a number of close, regular lines.

Pen writing implement

A pen is a writing instrument used to apply ink to a surface, usually paper, for writing or drawing. Historically, reed pens, quill pens, and dip pens were used, with a nib dipped in ink. Ruling pens allow precise adjustment of line width, and still find a few specialized uses, but technical pens such as the Rapidograph are more commonly used. Modern types include ballpoint, rollerball, fountain and felt or ceramic tip pens.

Raster graphics dot matrix data structure, representing a generally rectangular grid of pixels, or points of color, viewable via a monitor, paper, or other display medium

In computer graphics, a raster graphics or bitmap image is a dot matrix data structure that represents a generally rectangular grid of pixels, viewable via a monitor, paper, or other display medium. Raster images are stored in image files with varying formats.

Hatching

Hatching is an artistic technique used to create tonal or shading effects by drawing closely spaced parallel lines. When lines are placed at an angle to one another, it is called cross-hatching.

Plotters offered the fastest way to efficiently produce very large drawings or color high-resolution vector-based artwork when computer memory was very expensive and processor power was very limited, and other types of printers had limited graphic output capabilities.

Computer memory physical device used to store programs or data for use in a digital electronic device; computer hardware device used to store information for immediate use in a computer

In computing, memory refers to the computer hardware integrated circuits that store information for immediate use in a computer; it is synonymous with the term "primary storage". Computer memory operates at a high speed, for example random-access memory (RAM), as a distinction from storage that provides slow-to-access information but offers higher capacities. If needed, contents of the computer memory can be transferred to secondary storage; a very common way of doing this is through a memory management technique called "virtual memory". An archaic synonym for memory is store.

Pen plotters have essentially become obsolete, and have been replaced by large-format inkjet printers and LED toner based printers. Such devices may still understand vector languages originally designed for plotter use, because in many uses, they offer a more efficient alternative to raster data.

Wide format printers are generally accepted to be any computer-controlled printing machines (printers) that support a maximum print roll width of between 18" and 100". Printers with capacities over 100" wide are considered super wide or grand format. Wide format printers are used to print banners, posters, trade show graphics, wallpaper, murals, backlit film (duratrans), vehicle image wraps, electronic circuit schematics, architectural drawings, construction plans, backdrops for theatrical and media sets, and any other large format artwork or signage. Wide format printers usually employ some variant of inkjet or toner based technology to produce the printed image; and are more economical than other print methods such as screen printing for most short-run print projects, depending on print size, run length, and the type of substrate or print medium. Wide format printers are usually designed for printing onto a roll of print media that feeds incrementally during the print process, rather than onto individual sheets.

Electrostatic plotters

Electrostatic plotters used a dry toner transfer process similar to that in many photocopiers. They were faster than pen plotters and were available in large formats, suitable for reproducing engineering drawings. The quality of image was often not as good as contemporary pen plotters. Electrostatic plotters were made in both flat-bed and drum types.

An electrostatic plotter is a type of plotter that draws images on paper with an electrostatic process. They are most frequently used for Computer-Aided Engineering (CAE), producing raster images via either a Liquid Toner or a Dry Toner model.

Xerography

Xerography or electrophotography is a dry photocopying technique. Its fundamental principle was invented by American physicist Chester Carlson and based on Hungarian physicist Pál Selényi's publications. Chester Carlson applied for and was awarded U.S. Patent 2,297,691 on October 6, 1942. The technique was originally called electrophotography. It was later renamed xerography—from the Greek roots ξηρός xeros, "dry" and -γραφία -graphia, "writing"—to emphasize that, unlike reproduction techniques then in use such as cyanotype, this process used no liquid chemicals.

Photocopier device for reproducing documents

A photocopier is a machine that makes copies of documents and other visual images onto paper or plastic film quickly and cheaply. Most modern photocopiers use a technology called xerography, a dry process that uses electrostatic charges on a light-sensitive photoreceptor to first attract and then transfer toner particles onto paper in the form of an image. Heat, pressure or a combination of both is then used to fuse the toner onto the paper. Copiers can also use other technologies such as ink jet, but xerography is standard for office copying. Earlier versions included the Gestetner stencil duplicator, invented by David Gestetner in 1881.

Cutting plotters

Cutting plotters use knives to cut into a piece of material (such as paper, mylar or vinyl) that is lying on the flat surface area of the plotter. It is achieved because the cutting plotter is connected to a computer, which is equipped with specialized cutting design or drawing computer software programs. Those computer software programs are responsible for sending the necessary cutting dimensions or designs in order to command the cutting knife to produce the correct project cutting needs. [1]

In recent years the use of cutting plotters (generally called die-cut machines) has become popular with home enthusiasts of paper crafts such as cardmaking and scrapbooking. Such tools allow desired card shapes to be cut out very precisely, and repeated perfectly identically.

History

A number of printer control languages were created to operate pen plotters, and transmit commands like "lift pen from paper", "place pen on paper", or "draw a line from here to here". Three common ASCII-based plotter control languages are Hewlett-Packard's HP-GL, its successor HP-GL/2 and Houston Instruments DMPL. Here is a simple HP-GL script drawing a line :

SP1; PA500,500; PD; PR0,1000; PU; SP;

This program instructs the plotter, in order, to take the first pen (SP1 = Select Pen 1), to go to coordinates X=500, Y=500 on the paper sheet (PA = Plot Absolute), to lower the pen against the paper (PD = Pen Down), to move 1000 units in the Y direction (thus drawing a vertical line - PR = Plot Relative), to lift the pen (PU = Pen Up) and finally to put it back in its stall.

Programmers using FORTRAN or BASIC generally did not program these directly, but used software packages, such as the Calcomp library, or device independent graphics packages, such as Hewlett-Packard's AGL libraries or BASIC extensions or high end packages such as DISSPLA. These would establish scaling factors from world coordinates to device coordinates, and translate to the low level device commands. For example, to plot X*X in HP 9830 BASIC, the program would be

10 SCALE -1,1,1,1 20 FOR X =-1 to 1 STEP 0.1 30 PLOT X, X*X 40 NEXT X 50 PEN 60 END
Label plotter

Early pen plotters, e.g., the Calcomp 565 of 1959, worked by placing the paper over a roller that moved the paper back and forth for X motion, while the pen moved back and forth on a track for Y motion. The paper was supplied in roll form and had perforations along both edges that were engaged by sprockets on the rollers.

Another approach, e.g. Computervision's Interact I, involved attaching ball-point pens to drafting pantographs and driving the machines with stepper motors controlled by the computer. This had the disadvantage of being somewhat slow to move, as well as requiring floor space equal to the size of the paper, but could double as a digitizer. A later change was the addition of an electrically controlled clamp to hold the pens, which allowed them to be changed, and thus create multi-colored output.

Hewlett Packard and Tektronix produced small, desktop-sized flatbed plotters in the late 1960s and 1970s. The pens were mounted on a traveling bar, whereby the y-axis was represented by motion up and down the length of the bar and the x-axis was represented by motion of the bar back and forth across the plotting table. Due to the mass of the bar, these plotters operated relatively slowly.

In the 1980s, the small and lightweight HP 7470 introduced the "grit wheel" mechanism, eliminating the need for perforations along the edges, unlike the Calcomp plotters two decades earlier. The grit wheels at opposite edges of the sheet press against resilient polyurethane-coated rollers and form tiny indentations in the sheet. As the sheet is moved back and forth, the grit wheels keep the sheet in proper registration due to the grit particles falling into the earlier indentations, much like the teeth of two gears meshing. The pen is mounted on a carriage that moves back and forth in a line between the grit wheels, representing the orthogonal axis. These smaller "home-use" plotters became popular for desktop business graphics and in engineering laboratories, but their low speed meant they were not useful for general printing purposes, and different conventional printer would be required for those jobs. One category, introduced by Hewlett Packard's MultiPlot for the HP 2647, was the "word chart", which used the plotter to draw large letters on a transparency. This was the forerunner of the modern Powerpoint chart. With the widespread availability of high-resolution inkjet and laser printers, inexpensive memory and computers fast enough to rasterize color images, pen plotters have all but disappeared. However, the grit wheel mechanism is still found in inkjet-based, large format engineering plotters.

Inkjet plotter Plotter Algotex.jpg
Inkjet plotter

Plotters were also used in the Create-A-Card kiosks that were available for a while in the greeting card area of supermarkets that used the HP 7475 six-pen plotter.

Plotters are used primarily in technical drawing and CAD applications, where they have the advantage of working on very large paper sizes while maintaining high resolution. Another use has been found by replacing the pen with a cutter, and in this form plotters can be found in many garment and sign shops.

Changing the color or width of a line required the plotter to change pens. This was either done manually on small plotters, but more typically the plotter would have a magazine of four or more pens which could be automatically mounted.

A niche application of plotters is in creating tactile images for visually handicapped people on special thermal cell paper.

Unlike other printer types, pen plotter speed is measured by pen speed and acceleration rate, instead of by page printing speed. A pen plotter's speed is primarily limited by the type of pen used, so the choice of pen is a key factor in pen plotter output speed. Indeed, most modern pen plotters have commands to control slewing speed, depending on the type of pen currently in use.

There are many types of plotter pen, some of which are no longer mass-produced. Technical pen tips are often used, many of which can be renewed using parts and supplies for manual drafting pens. Early HP flatbed and grit wheel plotters used small, proprietary fiber-tipped or plastic nib disposable pens.

One type of plotter pen uses a cellulose fiber rod inserted through a circular foam tube saturated with ink, with the end of the rod sharpened into a conical tip. As the pen moves across the paper surface, capillary wicking draws the ink from the foam, down the rod, and onto the paper. As the ink supply in the foam is depleted, the migration of ink to the tip begins to slow down, resulting in faint lines. Slowing the plotting speed will allow the lines drawn by a worn-out pen to remain dark, but the fading will continue until the foam is completely depleted. Also, as the fiber tip pen is used, the tip slowly wears away on the plotting medium, producing a progressively wider, smudged line.

Ball-point plotter pens with refillable clear plastic ink reservoirs are available. They do not have the fading or wear effects of fiber pens, but are generally more expensive and uncommon. Also, conventional ball-point pens can be modified to work in most pen plotters.

Vinyl cutter

Drag-knife cutting plotter in action

A vinyl cutter (sometimes known as a cutting plotter) is used to create posters, billboards, signs, T-shirt logos, and other weather-resistant graphical designs. The vinyl can also be applied to car bodies and windows for large, bright company advertising and to sailboat transoms. A similar process is used to cut tinted vinyl for automotive windows.

Colors are limited by the collection of vinyl on hand. To prevent creasing of the material, it is stored in rolls. Typical vinyl roll sizes are 15-inch, 24-inch, 36-inch and 48-inch widths, and have a backing material for maintaining the relative placement of all design elements.

Vinyl cutter hardware is similar to a traditional plotter except that the ink pen is replaced by a very sharp knife to outline each shape, and may have a pressure control to adjust how hard the knife presses down into the vinyl film, preventing the cuts from also penetrating the backing material. Besides losing relative placement of separate design elements, loose pieces cut out of the backing material may fall out and jam the plotter roll feed or the cutter head. After cutting, the vinyl material outside of the design is peeled away, leaving the design on the backing material which can be applied using self-adhesion, glue, lamination, or a heat press.

The vinyl knife is usually shaped like a plotter pen and is also mounted on a swivel head so that the knife edge self-rotates to face the correct direction as the plotter head moves.

Vinyl cutters are primarily used to produce single-color line art and lettering. Multiple color designs require cutting separate sheets of vinyl, then overlaying them during application; but this process quickly becomes cumbersome for more than a couple of hues.

Sign cutting plotters are in decline in applications such as general billboard design, where wide-format inkjet printers that use solvent-based inks are employed to print directly onto a variety of materials. Cutting plotters are still relied upon for precision contour-cutting of graphics produced by wide-format inkjet printers – for example to produce window or car graphics, or shaped stickers.

Large-format inkjet printers are increasingly used to print onto heat-shrink plastic sheeting, which is then applied to cover a vehicle surface and shrunk to fit using a heat gun, known as a vehicle wrap.

Static cutting table

A static cutting table is a type of cutting plotter used a large flat vacuum table. It is used for cutting non-rigid and porous material such as textiles, foam, or leather, that may be too difficult or impossible to cut with roll-fed plotters. Static cutters can also cut much thicker and heavier materials than a typical roll-fed or sheet-fed plotter is capable of handling.

The surface of the table has a series of small pinholes drilled in it. Material is placed on the table, and a coversheet of plastic or paper is overlaid onto the material to be cut. A vacuum pump is turned on, and air pressure pushes down on the coversheet to hold the material in place. The table then operates like a normal vector plotter, using various cutting tools to cut holes or slits into the fabric. The coversheet is also cut, which may lead to a slight loss of vacuum around the edges of the coversheet, but this loss is not significant.

Contemporary uses of pen plotters

In the mid-to-late 2000s artists and hackers [2] [3] began to rediscover pen plotters as quirky, customizable output devices. The quality of the lines produced by pens on paper is quite different from other digital output techniques. Even 30-year-old pen plotters typically still function reliably, and many were available for less than $100 on auction and resale websites. While support for driving pen plotters directly or saving files as HPGL has disappeared from most commercial graphics applications, several contemporary software packages [4] [5] [6] [7] make working with HPGL on modern operating systems possible.

As use of plotters has waned, the large-format printers that have largely replaced them have come to be called plotters as well.

See also

Related Research Articles

Printer (computing) electronic device which produces a representation of an electronic document on physical media

In computing, a printer is a peripheral device which makes a persistent human-readable representation of graphics or text on paper. The first computer printer designed was a mechanically driven apparatus by Charles Babbage for his difference engine in the 19th century; however, his mechanical printer design was not built until 2000. The first electronic printer was the EP-101, invented by Japanese company Epson and released in 1968. The first commercial printers generally used mechanisms from electric typewriters and Teletype machines. The demand for higher speed led to the development of new systems specifically for computer use. In the 1980s were daisy wheel systems similar to typewriters, line printers that produced similar output but at much higher speed, and dot matrix systems that could mix text and graphics but produced relatively low-quality output. The plotter was used for those requiring high quality line art like blueprints.

In digital printing, a page description language (PDL) is a computer language that describes the appearance of a printed page in a higher level than an actual output bitmap. An overlapping term is printer control language, which includes Hewlett-Packard's Printer Command Language (PCL). PostScript is one of the most noted page description languages. The markup language adaptation of the PDL is the page description markup language.

Laser printing type of printer

Laser printing is an electrostatic digital printing process. It produces high-quality text and graphics by repeatedly passing a laser beam back and forth over a negatively charged cylinder called a "drum" to define a differentially charged image. The drum then selectively collects electrically charged powdered ink (toner), and transfers the image to paper, which is then heated in order to permanently fuse the text, imagery, or both. As with digital photocopiers, laser printers employ a xerographic printing process. However, laser printing differs from analog photocopiers in that the image is produced by the direct scanning of the medium across the printer's photoreceptor. This enables laser printing to copy images more quickly than most photocopiers.

Inkjet printing Type of computer printing

Inkjet printing is a type of computer printing that recreates a digital image by propelling droplets of ink onto paper, plastic, or other substrates. Inkjet printers are the most commonly used type of printer, and range from small inexpensive consumer models to expensive professional machines.

HP-GL, short for Hewlett-Packard Graphics Language and often written as HPGL, is a printer control language created by Hewlett-Packard (HP). HP-GL was the primary printer control language used by HP plotters. It was introduced with the plotter HP-8972 in 1977 and became a standard for almost all plotters. Hewlett-Packard's printers also usually support HP-GL/2 in addition to PCL.

Stationery writing materials

Stationery is a mass noun referring to commercially manufactured writing materials, including cut paper, envelopes, writing implements, continuous form paper, and other office supplies. Stationery includes materials to be written on by hand or by equipment such as computer printers.

Decal plastic, cloth, paper, or ceramic substrate that has a pattern or image printed on it

A decal or transfer is a plastic, cloth, paper or ceramic substrate that has printed on it a pattern or image that can be moved to another surface upon contact, usually with the aid of heat or water.

Digital printing

Digital printing refers to methods of printing from a digital-based image directly to a variety of media. It usually refers to professional printing where small-run jobs from desktop publishing and other digital sources are printed using large-format and/or high-volume laser or inkjet printers. Digital printing has a higher cost per page than more traditional offset printing methods, but this price is usually offset by avoiding the cost of all the technical steps required to make printing plates. It also allows for on-demand printing, short turnaround time, and even a modification of the image used for each impression. The savings in labor and the ever-increasing capability of digital presses means that digital printing is reaching the point where it can match or supersede offset printing technology's ability to produce larger print runs of several thousand sheets at a low price.

HP Deskjet

Deskjet is a brand name for inkjet printers manufactured by Hewlett-Packard. These printers range from small domestic to large industrial models, although the largest models in the range have generally been dubbed DesignJet. The Macintosh-compatible equivalent was branded as the Deskwriter and competed with Apple's StyleWriter, and the all-in-one equivalent is called OfficeJet.

Calcomp plotter

The Calcomp 565 drum plotter, introduced in 1959, was one of the first computer graphics output devices sold. The computer could control in 0.01 inch increments the rotation of an 11 inch wide drum and the horizontal movement of a pen holder over the drum. The pen was pressed by a spring against paper scrolling across the drum. A solenoid could lift the pen off the paper. This arrangement allowed line drawings to be made under computer control. Years later Calcomp made model 563 which used a 30" wide drum.

Printer Command Language, more commonly referred to as PCL, is a page description language (PDL) developed by Hewlett-Packard as a printer protocol and has become a de facto industry standard. Originally developed for early inkjet printers in 1984, PCL has been released in varying levels for thermal, matrix, and page printers. HP-GL/2 and PJL are supported by later versions of PCL.

Scitex Vision was an Israel-based company that specialized in producing equipment for large- and very-large-format printing on both paper and specialty materials. It was part of Scitex Corporation Ltd. The operations of Scitex Vision, together with rights to the name Scitex were acquired by Hewlett-Packard in 2005.

HP Labs

HP Labs is the exploratory and advanced research group for HP Inc. HP Labs' headquarters is in Palo Alto, California and the group has research and development facilities in Bristol, UK. The development of programmable desktop calculators, inkjet printing, and 3D graphics are credited to HP Labs researchers.

Vinyl banners are a form of outdoor advertising. Most banners are now digitally printed on large format inkjet printers which are capable of printing a full color outdoor billboard on a single piece of material.

The HP 7470 was a small low-cost desktop pen plotter introduced by Hewlett Packard's San Diego division in 1982. It was the first small-format plot that moved the paper, rather than the pens. It used a revolutionary "grit wheel" design which moved the paper held in place by a wheel with embedded grit and a pinch roller.

Calcomp Technology, Inc., usually known as Calcomp, was a company best known for its Calcomp plotters.

Digital modeling and fabrication is a design and production process that combines 3D modeling or computing-aided design (CAD) with additive and subtractive manufacturing. Additive manufacturing is also known as 3D printing, while subtractive manufacturing may also be referred to as machining, and many other technologies can be exploited to physically produce the designed objects.

The Veris printer is a medium format 1500 DPI color inkjet printer manufactured by the Graphic Communications Group of Eastman Kodak, which is used for digital Prepress proofing. A refinement of the Iris printer, the Veris also uses a continuous flow ink system to produce continuous-tone output on specially designed media. Unlike most inkjet printers which fire drops only when needed, the Veris uses eight 1 micrometer glass jets that operate continuously under high pressure, vibrated by a piezoelectric crystal to produce drops at a 1 MHz rate, or 8 million drops per second in total. Drops that are not needed to form the image are deflected electrostatically into a waste collection system, and individual drops can be directed to a specific position on the media. The Veris prints with the same quality of the Iris, only faster because of the larger number of jets.

References

  1. Cutting plotter, CUTCNC cam, Oct 9, 2011.
  2. The Draftmasters (video), Vimeo.
  3. El Muro, Berlin: UDK, archived from the original on 2009-10-15.
  4. Chiplotle: an HPGL (Hewlett-Packard Graphics Language) Python API, Columbia.
  5. Processing .
  6. Hackaplot, HV‐A.
  7. New Designjet Plotters Launches by HP in 2015, HP.