Is Scanner Input or Output Device?

Scanners shine light beams on texts or graphic images and direct them into a computer system. Paper documents are an integral part of offices and may keep coming daily. A scanner, therefore, is essential for converting and storing them forever. But is a scanner an input or output device?

Scanners are light-sensitive electronic devices that use optical character recognition (OCR) to process objects or documents into digital form. Scanning captures physical documents such as certificates and transforms them digitally into pdf files. As such, scanners are input devices.

Various scanners in the market today have different technologies for digitizing documents. High-end scanners use photo-multiplier tubes (PMT), whereas smaller and lighter scanners use contact image sensors (CIS).                                                                                                                      

Java-SE1712: File input/output, L...
Java-SE1712: File input/output, Lớp File

Is scanner an input or output device?

Scanning technology uses sensitive light receptors to detect light frequency and intensity changes. Some scanners use lasers to obtain the coordinates of text and graphics and use software to rebuild them into an image for computers. Considering that scanners transform hard copies into soft copies of information, they are input devices.

Output devices perform the opposite task. For instance, Printers are output devices because they translate virtual information on paper and 3D objects. You do not use a scanner to produce anything from a computer but to put documents in it. Thus the term “input.”

Unlike other input devices, scanners are optical input devices using light to achieve their objective. Optical character recognition (OCR) allows scanners to feed the computers with editable ASCII text.

In other words, the OCR software allows for interpreting the scanned bitmap image into words and letters recognized by the computer. A computer is considered the central device, whereas scanners are input devices. OCR uses feature detection and pattern recognition to identify characters and colors.

As a result, scanners can identify letters and numbers in any font using specific features. The reading is converted to ASCII code, which is suitable for a computer system. The code allows you to manipulate the document further.

Therefore, a scanner is an input device as it can send the document from your file to your computer. However, the scanned copy can have some basic errors that you should proofread before storing the file for future reference.

It is worth noting that a scanner is a peripheral device that a computer can do without. However, you can face significant challenges when you must disseminate soft copies of physical documents to various clients or departments without it. Therefore scanners are essential input devices for an effective office file management system.

Why a scanner is an input device and not an output

Except for 3-in-1 printers, which are both input and output devices, all dedicated scanners are input devices. A 3-in-1 printer can perform all three functions: scan, copy, and print documents. They are also referred to as multi-function printers. However, I prefer a dedicated scanner if your office produces highly digital artwork.

Nonetheless, a scanner is always an input device. Whether it is the flatbed scanner, handheld, or drum scanner, they all pick the coordinates of the shades on a document. They use optical character recognition to represent the documents in virtually any format. However, pdf is the most commonly preferred format for scanning documents.

Pdf format is essential for documents your office may want to release publicly or share with other people. You should scan annual reports, contracts, and promissory notes and file their soft copies on a computer. As such, you create a digital database of information that is more secure, reliable, and easy to retrieve.

Think of scanning as entering the virtual space. You have a physical object or document, and you need to view it through the computer monitor. Scanners are the perfect machines for that purpose. That is why a scanner is an input device and not an output. Because you put in additional files to your computer through it.

Output devices do not work like that. Unlike input devices, these give us results of what we send to a computer system. For example, a monitor displays the result of your activity. Speakers are also peripheral output devices that give out audio signals.

What output and input devices have in common is that they remove something from the computer and serve it to us. On the contrary, input devices such as scanners take our effort and keep it virtually. Other examples of input devices include barcode readers and digital cameras.

The computer only provides us with an interface for manipulating our input. Knowing that a scanner is an input device is not enough, though. Understanding how scanners work as input devices is also crucial.

How does a scanner works as an input device?

Scanners are light-sensitive electronic devices that use optical character recognition (OCR) to process objects or documents into digital images. However, there are various scanners in the market with different technologies for digitizing documents. High-end scanners use photomultiplier tubes (PMT), whereas small and lighter scanners use contact image sensors (CIS).

Photomultiplier tubes are highly sensitive photoemissive detectors. They can detect light at the photon level and scan documents with significant precision. Scanners that use CIS and PMT have a glass plate to place the paper for scanning.  Scanners digitize printed pages or graphics by converting them to tiny pixels we can interpret on monitors.

Like I said before, light plays a key role in scanning documents. Lay the paper you want to scan on top of the scanner’s glass plate and cover the top. According to the set instructions, a scanning unit moves and shines light across the document. Mirrors reflect and direct the light through the scanner lens to the sensors.

The scanner senses light variations as they penetrate through the document. When transmitted to the computer, a scanned file is made of pixels. Scanners have different resolutions that you can change to suit your objectives. I recommend a DPI scan above 600 for office archives because they take a long time to scan and require large storage spaces.

You can customize the color and size of the scanned virtual copy. Most importantly, scanning allows you enormous file formats. You can scan documents and store them on a computer in the form of pdfs, tiffs, jpeg, or png. However, the most common format for saving scanned official documents is the portable document format (pdf).

In a nutshell, all dedicated scanners are input devices. Multifunction printers that scan, copy, and print documents are considered input and output devices. However, dedicated scanners can be very costly since they produce high-quality images.

Generally, scanners are an integral part of an office for an effective file management system.

Sources and references

The University of New Mexico. (2016). Computer Concepts and Terminology: Input and Output Devices.

The U.S National Archives and Records Administration. (2016). Scanning Documents in the Research Rooms.

FTMS College. (2019). Chapter 3: Input Devices.

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