PRINTER LASER JET (pencetak laser)

Pencetak laser atau printer laser adalah pencetak untuk komputer yang menggunakan teknologi diode cahaya untuk mendapatkan partikel-partikel kecil toner dari cartridge ke kertas. Alat ini sering lebih ekonomis dibanding menggunakan tinta pencetak tinta.

Proses Pencetak laser bekerja dengan melibatkan 7 langkah:

Pemrosesan Gambar Raster:

peosesor dalam pencetak mengubah data untuk dicetak dari format apapun yang ada, ke bitmap halaman untuk dicetak - yang kemudian disimpan dalam memori gambar raster.

Pengisian:

Sebuah muatan elektrostatik kemudian diproyeksikan ke drum fotosensitif berputar dalam pencetak.

Penulisan:

Sinar laser diarahkan pada cermin poligon berputar, yang mengalihkan sinar itu ke drum fotosensitif. Data yang dirasterisasi kini dibaca, dan digunakan untuk mengendalikan apakah laser itu menyala atau tidak, karena sinar itu menyapu drum - di mana ketika sinar laser mengenai drum muatannya dibalik, menciptakan gambaran listrik laten di permukaan.

Perkembangan:

Permukaan drum kemudian dipajankan ke partikel toner bermuatan negatif, yang ditarik ke daerah di mana laser itu menulis gambaran listrik tersimpan. Toner itu akan diusir oleh muatan negatif daerah di drum di mana sinar laser tak mengenainya, dan kemudian menghilangkan muatan.

Transfer:

Drum sekarang diputar ke kertas, mengubah gambar dari drum ke kertas (untuk membantu proses ini ada pemutar bermuatan positif di belakang kertas, yang mendorong toner dari drum dan ke kertas).

Penggabungan:

Kertas kemudian dilewatkan melalui penggabung, di mana pemutar itu menyiapkan panas dan tekanan untuk mengikat toner ke kertas.

Pembersihan:

Sebuah tangkai tak bermuatan listrik dan lampu penembak menghilangkan toner dan semua muatan yang tersisa di drum (semua ini akan terjadi dalam 1

revolusi drum).

PRINTER INK JET (pencetak dakwat)

Pencetak jet dakwat merujuk kepada jenis pencetak komputer bukan hentaman yang menggunakan dakwat cair yang disemburkan kepada kertas. Ia merupakan pencetak komputer paling biasa bagi kegunaan umum disebabkan kos rendah, output berkualiti tinggi, keupayaan mencetak dalam warna yang terang dan mudah digunakan.

Sebagaimana kebanyakan teknologi moden, pencetak jet dakwat masakini dibina berasaskan kemajuan oleh versi terdahulu. Antara penyumbang termasuk Epson, Hewlett-Packard dan Canon boleh mendakwa turut menyumbang sebahagian besar kepada pembangunan pencetak jet dakwat moden. Dipasaran pengguna di seluruh dunia, keempat pengilang bertanggung jawab bagi sebahagian besar pencetak jet dakwat: Canon, Hewlett-Packard, Epson, dan Lexmark

Kemunculan pasaran memasukkan bahan jet dakwat (Ink jet material deposition) turut menggunakan teknologi jet dakwat, biasanya jet dakwat piezoeletrik, bagi melekatkan bahan secara langsung kepada substrate.

PRINTER DOT MATRIX

A dot matrix printer or impact matrix printer is a type of computer printer with a print head that runs back and forth on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper, much like a typewriter. Unlike a typewriter or daisy wheel printer, letters are drawn out of a dot matrix, and thus, varied fonts and arbitrary graphics can be produced. Because the printing involves mechanical pressure, these printers can create carbon copies and carbonless copies.

Each dot is produced by a tiny metal rod, also called a "wire" or "pin", which is driven forward by the power of a tiny electromagnet or solenoid, either directly or through small levers (pawls). Facing the ribbon and the paper is a small guide plate (often made of an artificial jewel such as sapphire or ruby [1]) pierced with holes to serve as guides for the pins. The moving portion of the printer is called the print head, and when running the printer as a generic text device generally prints one line of text at a time. Most dot matrix printers have a single vertical line of dot-making equipment on their print heads; others have a few interleaved rows in order to improve dot density.

These machines can be highly durable. When they do wear out, it is generally due to ink invading the guide plate of the print head, causing grit to adhere to it; this grit slowly causes the channels in the guide plate to wear from circles into ovals or slots, providing less and less accurate guidance to the printing wires. Eventually, even with tungsten blocks and titanium pawls, the printing becomes too unclear to read.

Although nearly all inkjet, thermal, and laser printers produce dot matrices, in common parlance these are seldom called "dot matrix" printers, to avoid confusion with dot matrix impact printers.

DVD-ROM ( pemacu cakera )

DVD (also known as "Digital Versatile Disc" or "Digital Video Disc" - see Etymology) is a popular optical disc storage media format. Its main uses are video and data storage. Most DVDs are of the same dimensions as compact discs (CDs) but store more than six times as much data.
Variations of the term DVD often describe the way data is stored on the discs: DVD-ROM has data which can only be read and not written, DVD-R and DVD+R can only record data once and then function as a DVD-ROM. DVD-RW, DVD+RW and DVD-RAM can both record and erase data multiple times. The wavelength used by standard DVD lasers is 650 nm[1], and thus has a red color.

DVD-Video and DVD-Audio discs respectively refer to properly formatted and structured video and audio content. Other types of DVDs, including those with video content, may be referred to as DVD-Data discs. As next generation High definition optical formats also use a disc identical in some aspects yet more advanced than a DVD, such as Blu-ray Disc, the original DVD is occasionally given the retronym SD DVD (for standard definition).[2][3]

CD-ROM ( pemacu cakera )

CD-ROM (an initialism of "Compact Disc Read-Only Memory") is a pre-pressed Compact Disc that contains data accessible to, but not writable by, a computer. While the Compact Disc format was originally designed for music storage and playback, the 1985 “Yellow Book” standard developed by Sony and Philips adapted the format to hold any form of binary data.

CD-ROMs are popularly used to distribute computer software, including games and multimedia applications, though any data can be stored (up to the capacity limit of a disc). Some CDs hold both computer data and audio with the latter capable of being played on a CD player, whilst data (such as software or digital video) is only usable on a computer (such as PC CD-ROMs). These are called Enhanced CDs.

Although many people use lowercase letters in this acronym, proper presentation is in all capital letters with a hyphen between CD and ROM. It was also suggested by some, especially soon after the technology was first released, that CD-ROM was an acronym for "Compact Disc read-only-media", or that it was a more "correct" definition. This was not the intention of the original team who developed the CD-ROM, and common acceptance of the "memory" definition is now almost universal. This is probably in no small part due to the widespread use of other "ROM" acronyms such as Flash-ROMs and EEPROMs where "memory" is usually the correct term.

CD-ROM format

A CD-ROM sector contains 2352 bytes, divided into 98 24-byte frames. The CD-ROM is, in essence, a data disk, which cannot rely on error concealment, and therefore requires a higher reliability of the retrieved data. In order to achieve improved error correction and detection, a CD-ROM has a third layer of Reed-Solomon error correction.[1]

A Mode-1 CD-ROM, which has the full three layers of error correction data, contains a net 2048 bytes of the available 2352 per sector.

In a Mode-2 CD-ROM, which is mostly used for video files, there are 2336 user-available bytes per sector.

The net byte rate of a Mode-1 CD-ROM, based on comparison to CDDA audio standards, is 44.1k/s×4B×2048/2352 = 153.6 kB/s.

The playing time is 74 minutes, or 4440 seconds, so that the net capacity of a Mode-1 CD-ROM is 682 MB.

A 1x speed CD drive reads 75 consecutive sectors per second.

FLOPPY ( pemacu cakera liut )

If you have spent any time at all working with a computer, then chances are good that you have used a floppy disk at some point. The floppy disk drive (FDD) was the primary means of adding data to a computer until the CD-ROM drive became popular. In fact, FDDs have been a key component of most personal computers for more than 20 years.

The major parts of a FDD include:

Read/Write Heads:

Located on both sides of a diskette, they move together on the same assembly. The heads are not directly opposite each other in an effort to prevent interaction between write operations on each of the two media surfaces. The same head is used for reading and writing, while a second, wider head is used for erasing a track just prior to it being written. This allows the data to be written on a wider "clean slate," without interfering with the analog data on an adjacent track.

Drive Motor:

A very small spindle motor engages the metal hub at the center of the diskette, spinning it at either 300 or 360 rotations per minute (RPM).

Stepper Motor:

This motor makes a precise number of stepped revolutions to move the read/write head assembly to the proper track position. The read/write head assembly is fastened to the stepper motor shaft.

Mechanical Frame:

A system of levers that opens the little protective window on the diskette to allow the read/write heads to touch the dual-sided diskette media. An external button allows the diskette to be ejected, at which point the spring-loaded protective window on the diskette closes.

Circuit Board:

Contains all of the electronics to handle the data read from or written to the diskette. It also controls the stepper-motor control circuits used to move the read/write heads to each track, as well as the movement of the read/write heads toward the diskette surface.

HARDISK ( pemacu cakera keras )

Cakera keras adalah sekeping logam tetap yang menyimpan data sebagai bintik magnetik. Setiap kepingan logam itu disadur dengan ferum oksida.

Keseluruhan unit cakera keras dibungkus dalam kotak dimeterai, yang di dalamnya terdapat cakera keras, satu set pemacu cakera dan motor yang memutarkan cakera. Ini berbeza dengan cakera liut yang cakera dan pemacu cakera terasing. Unit yang mempunyai satu kepala baca/tulis, satu lengan capaian dan satu keping cakera yang termeterai juga dikenali sebagai Pemacu Cakera Winchester (Winchester disk drives).

Permukaan cakera keras dan kepala baca/tulis begitu rapat sehingga sebarang partikel kotoran boleh menjejaskan kelancaran proses baca/tulis dan juga menyebabkan head crash. Kejadian ini akan merosakkan permukaan cakera keras (data akan hilang) dan juga merosakkan kepala baca/tulis.


Kaedah data disimpan pada cakera keras hampir sama dengan kaedah penyimpanan cakera liut iaitu kaedah jejak dan sektor. Bagaimanapun, cakera keras boleh terdiri lebih daripada satu kepingan dan kepala baca/tulis. Bentuk cakera keras sedemikian disebut pek cakera (disk pack). Pek cakera keras boleh terdapat sehingga 12 atau lebih kepingan cakera magnetik. Jika ini keadaannya, satu konsep "silinder (cylinder)" digunakan. Kaedah silinder ini adalah satu kaedah menyimpan data pada jejak yang sama dan pada permukaan cakera yang berlainan.
Terdapat pelbagai variasi cakera keras untuk mikrokomputer:


a)Pemacu Cakera Keras Luaran (External Hard Disk Drives) yang boleh menyimpan
bergigabait data.

b)Pengecilan (Miniaturization)
Pemacu cakera keras sekarang lebih tipis daripada yang dahulu (3.5" kepada 1.5") dan juga
lebih kecil diameternya (daripada 3.5" atau 5.25" kepada 2.5", 1.8", 1.3"). Pengecilan saiz
ini akan membolehkan dua pemacu cakera ditempatkan pada ruang yang sama.

c)Katrij Cakera Keras (Hard Disk Cartridges)
Katrij cakera keras ini mengandungi satu atau dua keping cakera dan pemacu cakeradalam
satu kotak plastik keras. Katrij ini seperti cakera keras boleh pindah dan boleh menampung
sehingga 1.2 gigabait data. Ia adalah baik digunakan untuk salinan (back up).


Kelebihan cakera keras/Hard disk:

a) Muatan tinggi, disket 1.4MB tetapi hard disk menjangkau 16+ ( Pentium III ).

b) Masa mencapai data dari hard disk cepat, ia dapat mempercepatkan proses yang hendak
dibuat oleh pengguna.

c) Proses merekod data dari hard disk lebih cepat.