What is a Scanner in Computer | Types and Uses Updated in 2023

In this article, we will talk about What is a scanner in a computer, the different types of scanners, and their uses.

While the history of scanners traces back to around mid of 20th century, the computer scanner became well-known in the 2000s.

They remain popular and continue to develop, offering optimum results at nominal costs.

In the past, people were struggling to maintain their documents in hard copy formats or queue up at shops to get them photocopied for various purposes.

This not only led to the piling up of papers, but the probability of losing the paper also increased.

Thanks to the scanner that helped to manage all our documents in digital format, and made our life easier.

The scanner technology is known to be derived from telephotography, the only difference is that the former transmits the entire image, whereas the latter transmits only the text.

The resolutions of the telephotography were not up to the desired mark and also required huge space due to equipment dimensions and high power consumption.

The need for an hour was to have a device that is lightweight, compact, and processes images with high resolution.

The first realistic image transmitted belongs to Russell Kirsch’s son, who was working on scanning technology.

What is a Scanner?

What is a scanner and its uses
What is a scanner?

In layman’s terms, a scanner is an electronic device that can scan handwritten or printed documents and pictures and transforms them into a digital file format.

Let’s understand and explore what a scanner does to make our work easier.

In computer terminology, a scanner is an input device capable of scanning images and texts on paper.

This is then converted by the scanner into a digital file (soft copy) and stored in electronic form on a computer or mobile device.

The scanned document can be viewed, shared, edited, and also take printouts on the computer.

How does a scanner work in a computer?

The functioning of the scanner is very simple and works on the principle of reflection and transmission.

A bright light shines on the document to be converted into a digital copy and is reflected onto a sensor (photosensitive element) after passing through a series of mirrors and lenses.

In most scanners, these sensors or the medium is an electronic integrated circuit called a Charged coupled device (CCD).

The photosites displayed on the CCD convert the light intensity into electronic signals to further process into a digital photo.

While CCD is the widely used technology in today’s scanners, Photomultiplier tube (PMT) and Contact Image Sensor (CIS) technology is also used in some of the high-end and budget scanners.

The PMT technology used in drum scanners offers high-quality resolution images but is used in very limited areas due to its dimensions, power consumption, etc.

Whereas the CIS is the newest technology but lacks resolution, depth of field, and varying range.

The technology used by low-end small handy digital cameras is Complementary Metal Oxide Semiconductor (CMOS) due to being cost economical, less power consumption, and easy integration into the devices resulting in affordable designs.

Some of the innovative designs of CMOS technology are gaining popularity in professional digital cameras (DSLRs), but the CCD sensor technology continues to lead the high-end professional DSLRs market despite being expensive.

Many computer software programs work in combination with the scanner to import the data directly from the scanner.

The majority of the scanners are having a plug and play options with basic software for the operation of the scanner.

The user simply connects the scanner to the computer and scans the document or image and imports it to the computer.

Some of the software programs have plug-ins that are installed to enable them to use images directly from the scanners.

Adobe Photoshop plug-in allows us to generate images from the scanner directly.

Adobe Acrobat and other software have Optical character recognition technology by which they can also identify scanned text.

Once the text document is scanned, the software with OCR transforms the document into digital text that can be edited in a Word document.

Some of the software can also scan documents with text, including the formatting to store them in physical form.

What is a Scanner Used for?

A scanner is one of the essential parts of computer hardware using light sensor technology to scan and convert the physical document or picture into a digital, computer-readable format.

The scanners are capable to scan black and white or color documents or pictures.

There are high and low-resolution scanners available in the market, and you can choose the one depending on the type of their applications.

The most common use of a scanner is for copying and is also an alternative to your normal copier machine.

In other words, if you do not have a copy photocopier machine but need many copies of your document, photo, presentations, etc. the scanner comes to your rescue as it makes a digital file of your physical document.

As long as the printer is connected to a computer, you can take any number of copies from the available digital file depending on your requirements.

Moreover, it also gives you the flexibility of editing your document before printing the same.

The scanner also helps with the record-keeping of important documents in digital format, which is also known as digital archiving.

In this, the scanner will scan the physical document and make digital copies of all your personal and business-related documentation, important paperwork, letters, agreements, certifications, tax papers, etc.

Having the digital file in addition to the physical document is valuable and retrieval of information and details from these documents can be a lot easier if the original documents get misplaced or are lost.

Another important area of application is for research purposes. Research work for school, college, or business purposes would require a lot of data and information, and some of this information would be available in books borrowed from the library or other sources.

In case, if the information is required at a later date during research, we can make use of a scanner for scanning the important pages and storing it in the computer to be referred to later when the need arises.

Before digital photography became an advent, all the photographs were taken with the traditional film roll camera and are available in hard copy format only.

Scanners help you to transform this hard copy of photos into digital copies, which can be shared with friends and families over the internet.

Types of Scanner

The scanners have been a boon to businesses as they can easily manage all the documents in digital format and save it as records.

Scanners were mostly seen in offices and large institutions owing to the record-keeping of many documents, but nowadays, it is being used by almost every individual for scanning works.

Below are some of the common types of scanners available today, and you can choose one of them that best suits your requirements.

Flatbed scanner

This is the most common and simplest scanner available in the market for home and business applications.

It is placed on a flat desk surface and has a lid that can be flipped open to view the glass that scans the document.

The lid is adjustable to take care of scanning from thick books, files or magazines, etc.

The document is placed on the top of the glass and below the glass is the moving light-capturing sensor, generally CCD or CIS display.

During the scanning process, the light source illuminates the glass and the moving sensor captures the image and converts it into digital format.

You can also scan the transparent slides and film negatives but will require a transparent media adapter.

With a flatbed scanner, you can scan almost all types of documents depending on the size.

Some flatbed scanners come with added features of Bluetooth or wireless connectivity and automatic feeders.

Photo scanner

If you are specifically looking for scanning images, pictures, and old photographs then you must go for the photo scanners as they will give premium results.

Although other scanners can also scan images, the results achieved through photo scanners will be far superior in terms of color depth and also when there is a large number of photographs to scan.

Some scanners come with their image editing software that offers the highest resolution and clears old photographs but this scanner is a bit more expensive than the other scanners.

Document scanner

As the name suggests, these scanners are used especially for scanning multiple documents in large sizes.

This is also called a sheetfed scanner since the documents are placed in the feeder and not on the flatbed glass.

It is an ideal option when you have limited space for working and need to scan thousands of pages daily.

Some of the sheetfed scanners have advanced features to make the scanning process more efficient and fast.

This is why they are a bit pricey compared to flatbed scanners.

Portable scanner

Portable scanners are handy and often come in a size that can fit in your pocket.

It can be carried anywhere and doesn’t require much power and works when connected to your handheld devices vide a USB port.

These can scan line by line of a page or scan completely while rolling it upside down.

Portable scanners are good at scanning documents but are not good enough with photos as compared to flatbed or photo scanners. 

Other types of scanners include slide scanners and multispecialty scanners that are used in offices and for specialized requirements.  

Advantages and Disadvantages of scanners

The scanners have added advantages in terms of increased efficiency and functionality at home or the workplace.

Even modern-day printers are multifunction having an inbuilt scanner capable of meeting your needs.

Importantly you need not buy a separate printer, or scanner thus saving your space.

The scanners offer quality results with high-resolution output as compared to the traditional fax machine that challenges itself to reproduce quality images and text.

The scanners are built to handle photos, text, designs, graphics, etc.

Unlike a fax machine that requires a dedicated phone line to function and produce results, scanners are independent and do not need any supporting device for their functioning, and the files are stored digitally on your computer.

The fax machine will need a phone line at your and the recipient’s end, whereas the scanner is reliable, and depending upon it, you can scan the document and send it to others via email or digital mode.

Scanners are environment friendly as they create digital copies of your documents, photos, and important files and can be shared over the internet vide email.

Whereas the fax machine needs paper to produce a copy, and every time it is sent to a recipient, it requires paper to produce the print output.

Scanning in a scanner is a one-time effort that saves time and energy.

In the case of the fax machine, you will have to spend time, energy, and effort every time the page is exchanged.

Using a scanner is pretty simple and does not require any complex setup and configurations.

Moreover, the built-in scanners that are part of multifunction printers only require simple fine-tuning and adjustments it is put to use.

Once setup is done, you only need to select photos, documents, or a combination of photos and text along with the color or black & white type, and the scanner will complete the process, and depending on the output selected, the file will be sent straight to your computer attaches directly to your email account.

The scanner offers the flexibility to save scanned documents or images in multiple formats including pdf documents.

The flatbed scanners require a large space and can be expensive for high-end business use.

There is a risk of the original document getting damaged in sheetfed scanners.


Hope you have got an adequate insight about the scanner and the types of scanners available in the market, it will now be easy for you to select the one that best suits your requirements.

The flatbed scanner is a multifunction scanner and can scan both images and documents, but each one’s need is different and specific.

People should make sure of the purpose for which they will be using the scanner before they choose to buy one for their needs.

To help you, we have summarized some important parameters to help you choose the right scanner.

  • The document size will define if you need a large or portable scanner. For scanning legal and A4-size documents, you will need a large scanner but for smaller documents, a portable scanner would be fine.
  • Output resolution. 200 PPI is good enough for documents but images need a minimum of 600 PPI.
  • Some of the scanners will not work with all the software so you need to choose the scanner that can easily integrate with the software on your computer.

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