# Printer Self-Alignment?

**URL:** <https://boards.straightdope.com/t/printer-self-alignment/780630>\
**Category:** Factual Questions\
**Created:** [February 24, 2017, 2:51pm UTC](https://boards.straightdope.com/t/printer-self-alignment/780630 "2017-02-24T14:51:07Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Jinx](https://avatars.discourse-cdn.com/v4/letter/j/c6cbf5/32.png) [@Jinx](https://boards.straightdope.com/u/Jinx)\
**Post date:** [February 24, 2017, 2:51pm UTC](https://boards.straightdope.com/t/printer-self-alignment/780630/1 "2017-02-24T14:51:07Z")

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I have a common, all-in-one HP printer. When you replace the print cartridges, you have to perform a printer realignment. Nowadays, this is a self-test the printer can perform by printing a test sheet with a pattern on it. One simply scans the test sheets, and magically the printer re-aligns itself. The question is: How can a non-aligned printer print a test page that will be used to self-align the printer? It’s akin to the blind leading the blind, isn’t it? How does this work?

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**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\
**Post date:** [February 24, 2017, 2:57pm UTC](https://boards.straightdope.com/t/printer-self-alignment/780630/2 "2017-02-24T14:57:23Z")

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It prints a bunch of different patterns on the alignment sheet and it has clear expectations as to what they should look like if it was properly aligned - from the specific way in which each pattern is different from expectations, it can deduce the way that the alignment needs to be adjusted.

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**Author:** ![dolphinboy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dolphinboy/32/330_2.png) [@dolphinboy](https://boards.straightdope.com/u/dolphinboy)\
**Post date:** [February 24, 2017, 3:43pm UTC](https://boards.straightdope.com/t/printer-self-alignment/780630/3 "2017-02-24T15:43:01Z")

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The alignment is usually pretty minor. If the alignment was really off the printed images would look bad in day-to-day use.

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**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\
**Post date:** [February 24, 2017, 8:26pm UTC](https://boards.straightdope.com/t/printer-self-alignment/780630/4 "2017-02-24T20:26:38Z")

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Have you done a “manual” alignment?

Various groups of short lines are drawn. With the segments offset a bit in each one. One row are horizontal, another vertical. Under each is a number. You tell the alignment program which ones line up best.

To automate this with a print and scan isn’t that hard. They can even do a more complicated pattern and do a better job.