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I worked in publishing in the UK and am trying to identify a dot matrix printer from 1987. I have binders full of printouts from this printer. I think I've identified that it is a 9-pin dot matrix printer. It had the ability of printing a more condensed version as well, as some of my printouts are more condensed. It was connected to a BBC Micro computer.

I am making a font to match the wider printout because I can't find one that is accurate to this particular model. (Most fonts assume that the horizontal dots are spaced the same as the vertical dots, but with this printer, the dots are spaced a tiny bit wider horizontally, like the top of the n, or the crossbar of the H, etc.)

I have analyzed the font extensively and am almost done with the GlyphsApp font. But I would like to know the printer brand! I assumed it was an Epson, but I can't find an image that matches.

I will attach images - one that I took in the office where I worked that shows the printer with 3 dark gray buttons. The other two are of printouts, wide and condensed.

EDIT Nov 22: Added 3 photos of the font in progress, including the M overlaid on the very helpful "Ideal M" from Comment.

dot matrix printer connected to BBC Micro

dot matrix sample printout scan wide font dot matrix sample printout scan condensed font example of the capital Q

SQ-80 font overlaid on printout

Q fixed

M in Glyphs

Font M pink overlaid on Ideal M

Grid in After Effects with font overlay

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  • 7
    Normal 9-pin printers used 120dpi horizontally and 72dpi vertically in normal 80-column mode, with a constraint that no dot could be horizontally adjacent to another. In emphasized mode which took twice as long to print, every dot had a second dot printed one column to its right. In condensed mode, resolution was increased to 240dpi, but two extra blank columns were added between characters. The lettering looks typical of such printers, but I don't have a font reference handy to see if any letter forms are unusual. The printout does not have the "Q" shape used by the Star Gemini 10x, ...
    – supercat
    Nov 17, 2022 at 20:39
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    Looks much like a CTI CP-80 - but not the Model II
    – Raffzahn
    Nov 17, 2022 at 20:41
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    ... and the X doesn't match my memory of what most printers would have used, but the "0" and "D" are pixel perfect to what I remember.
    – supercat
    Nov 17, 2022 at 20:44
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    @supercat - I added another image of a capital Q, if that's of interest. I have a year's worth of printouts (3 binders full) and this is the only Q I could find!
    – QuinGold
    Nov 17, 2022 at 22:58
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    @QuinGold: The Q definitely doesn't match that of the Star Gemini 10x as shown on page 239 of minuszerodegrees.net/manuals/Star%20Micronics/dot_matrix/… [which is labeled page 233] nor the MX-80 mirrors.apple2.org.za/ftp.apple.asimov.net/documentation/… (the S matches the Gemini but not the Epson). I find it interesting how many 9-pin printers have slight differences in their fonts.
    – supercat
    Nov 17, 2022 at 23:16

4 Answers 4

15

The printer looks quite like a C.T.I. CP-80 variant. The silver oval is a give away. See this picture of a CP-80 Model II I have pulled out a few weeks ago for a PC-XT setup to help with GlaBIOS.

enter image description here (picture mine)

These printers were sold under various "brands" (Shinwa, Computer Mate, ...) from the mid 1980s on. Essentially cheap rip off of Epson printers. There were at least 5 different models over the years.

Here's an add for the Model 2 from a British magazine, mentioning the BBC as well:

enter image description here

(Taken from an ebay sale)

Most fonts assume that the horizontal dots are spaced the same as the vertical dots, but with this printer, the dots are spaced a tiny bit wider horizontally, [...]

Well, that's the usual issue with recreated fronts as they build an idealized version that never was. Also, width is something that did vary always a bit as it relies on head movement which may differ over time and condidion.

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    The basic charset was 9x9 and please, do not expect any details past that it could do 80 characters in standard mode and maybe ~130 condensed. It's fruitless to apply today's features and detailed control with reality (and expectations) back then. Just look at the Ad and notice that it doesn't name any character or line spacing at all. Having 80 chars in ONE line is already the main achievement. And "true decenders" !!!!! Not to mention that the whole text is of course caps only :)) No offence, but it feels as if you're trying to recreate something better than new :)
    – Raffzahn
    Nov 17, 2022 at 22:46
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    @QuinGold In this class "styles" are an euphemism for printing the dos a bit wider or closer. Also don't forget that firing was in large a analogue process, meaning that a horizontal line of dots nay not be a straight die slightly different voltage/induction of the coil. Even worse, timing may vary depending on number of dots firing in the same column, shifting the whole column a bit and so on. I know, hard to believe for anyone custom to today's precision. Also an example why a professional printer back then was three or four times more expensive than above CP-80.
    – Raffzahn
    Nov 17, 2022 at 22:51
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    @QuinGold From the timing relation between head firing and head movement. The detail you just added shows perfectly that these printers did not deliver a great repetitive operation. It's random how hard a pin hits and at the same time when. Having random offsets from the desired point to the one produced of less than 1/3rd of a position was a good result. How bad mechanics were (by today's) standard even on high end printers is shown by them operating in high quality mode only in one direction, so errors due movement regularities are mostly the same in all liens :))
    – Raffzahn
    Nov 17, 2022 at 23:03
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    Thank you, that's helpful. This is for a handmade art book. I will print templates a few inches high, then using a light table, I can make the dots using calligraphy tools on the art paper on top. The dots I make will be a little "off" so that will mimic the printheads. I had to create a font as it was too difficult to remember the locations of all the dots! Some day I hope to have time to make a variation of my clean font, where the dots are all a little "off". I prefer the "dirty typewriter" fonts over the clean ones, so having a "wonky dot matrix" font makes sense to me.
    – QuinGold
    Nov 17, 2022 at 23:16
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    @QuinGold The whole point is to produce something that comes around to roughly 10 CPI for standard 80 char per line font, adding up to 8 inch width or 12 CPI for 132 characters which again adds up to 8". So if a character is made from a 9x9 cell, then those 8" contain 80x9=720 dots, with a dot being ~1/90" wide. This value is handled by the movement of the head - and how exact the transport works. Dot distance vertical in turn is fixed by the head - which usually is more exact. And all of that gets twisted by various random input - not to mention wear.
    – Raffzahn
    Nov 17, 2022 at 23:18
9

A useful place to start with the matrix dimensions is this diagram from the Epson LX-810 LX-850 Service Manual:

9-pin print head dimensions: each pin is 0.29 mm diameter, and pins are spaced 0.35 mm apart

Each pin is 0.29 mm diameter, and pins are spaced 0.35 mm apart vertically. Horizontally, the standard step distance was 0.21 mm. As others have said, because of physical limitations in the pin mechanics, horizontally-adjacent dots must be two steps apart, or 0.42 mm. These dimensions are likely common to most 9-pin printers, although one manufacturer I seem to remember used square pins.

If you build your font based on this, you'll get a theoretically accurate model of the device. Practically, however, impact printers suffered from dot gain: the physical dots tend to be much larger than the theoretical resolution. This dot gain depended on many variables: ribbon ink level, ribbon thickness/flexibility, print head wear, paper thickness setting, actual paper thickness, paper roughness, ink compatibility … At some point, a designer has to compromise/assume some of these values, and thus create an “idealized version that never was”, as Raffzahn put it.

dot matrix letter M from the Epson FX-80 ROM, shown as theoretical dot size and with simulated dot gain

There doesn't seem to be a ROM dump of the CTI CP-80 of any version on the internet, alas, or even a manual with a good character table available. For the programmatically inclined, Peter Hull's Effects Eighty may be an interesting place to start when creating a dot matrix look-alike. Although the font itself is based on an idealized version of the Epson FX-80, the font includes source to generate itself, and the characters are defined in a fairly intuitive way:

 ...
    "Q":
"""
............
............
............
.*.*.*.*....
*.......*...
*.......*...
*.......*...
*...*...*...
*.....*.....
.*.*.*..*...
............
............
""",
 ...

The font matrix looks the same as Epson printers. Here's the SQ-80 sample, with a slightly rescaled outline of Effects Eight overlaid. Plus or minus variations within the range of ink smearing and pin impression variation, they are the same data:

Effects Eighty overlaid on source image

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    thank you SO much for the "ideal" M. That was all I needed to check that my original dot was the right size, as well as to confirm the positioning of the dots horizontally. I think I'm almost there! Since I can't seem to post images in this comment, I will see if I can add 3 more images of my font in progress in the above post. I have "idealized" the font a little as I just can't "do" the bad letter spacing to that extent! I won't be adding hundreds of kerning pairs, but some of the obvious letters (like i, f, j, etc.) will be narrower than M, S, E, etc.
    – QuinGold
    Nov 23, 2022 at 0:41
  • Re: Effects Eighty - the download includes the Glyphs app source file which is the same app I'm using. His pin dots are much larger (they overlap) and it seems to be a more condensed font compared to the printouts I have. But interesting to poke around in!
    – QuinGold
    Nov 23, 2022 at 0:57
  • @QuinGold - yes, I'm not sure where the Effects Eighty author got those proportions from, but they don't seem to match anything real. You question has prompted me to finally finish an NLQ dot matrix font I started working on over five years ago, and the printout's been taunting me on my desk since then.
    – scruss
    Nov 23, 2022 at 2:49
  • The world needs more accurate dot matrix fonts, that's for sure! One nice thing is that the character set is pretty limited, and no one expects thousands of kerning pairs. I'm using Glyphs 3, and there is one dot that is saved as a _part and then used in all the glyphs. That means that if I change the size or shape of that source dot, I can make variations very easily. Since my dot matrix printouts are love letters across two continents, maybe I'll make one with a heart-shaped dot!
    – QuinGold
    Nov 23, 2022 at 18:22
  • I had to google NLQ (Near Letter Quality). There are some interesting links below this wiki article to old magazines. en.wikipedia.org/wiki/Near_letter-quality_printing
    – QuinGold
    Nov 23, 2022 at 18:27
3

This a CP80 which I imported from Japan when I owned Micro Peripherals (Micro P). We distributed it throughout Europe. The quality was not very good so we stopped selling after only a few months.

1

Well first off, let's eliminate some of the more common printers based on physical layout. I note that there doesn't appear to be any label on the front, where most printers would have one, but there appears to be a small one just above the buttons on the right. We also can't see either side of the printer where the paper knob would be, which would normally be helpful.

What we can see are a couple of details that seem useful:

  1. three operating buttons on the right, seemingly in chicklet style

  2. a metal paper "tray", which was not used by later printers

  3. the buttons are in an insert area and there is a "step" just to the left on the front which appears to be part of the holder for the top cover, which has been removed (and almost certainly has the logo!)

So based on this...

It's not any Centronics that I'm familiar with, they just look different. They were generally not in use by this point anyway as lower-cost companies entered the field.

It's not any of the more common Japanese names like Panasonic or Toshiba, they generally looked like Centronics.

It may be one of the many 9-pin Epson models. They mostly had three buttons on the right, as seen here, and generally in a slightly lowered section, as seen here. Most examples will have white plastic buttons, but I know they made some with dark grey chicklets as seen here. Most notable is the metal paper "tray" at the back, which does indeed seem similar to the Epson from the MX on. However, Epson always had a large metal label on the front on the left, which I do not see here, but it's possible it's just hidden. We also can't see the right side where Epson always had its paper knob. Finally, the covers on Epson normally sat in an indent, so the lip on the front here seems wrong.

So this is pushing me in the direction of one of the many Epson clones.

Judging by the style and placement of the buttons and the metal paper "basket" at the back, this may be a Star Micronics SG or gemini series, in particular, the gemini-10X. However, the Star always had a logo on the front right, which is missing, although it's possible the UK versions were whitelabled. The other issue is that the buttons in the image above are inset, while the geminis I know are flush with the top. I know there were some differences between models, including ones using white buttons and other minor differences. Unfortunately, I can't find any sample output to compare, although perhaps someone with better eyes than mine can find something useful here.

My feeling is that it is likely a model from the 1983 through 1986 time-frame, because after that you generally have sheet feeders instead of roll feeders. For instance, compare with the Star LC-100 and similar models of the later 1980s.

5
  • Thank you! I'm sorry that this is the only pic I have. It was also of a co-worker so I am assuming that we both had the same model. Being an Epson clone will have to do for now!
    – QuinGold
    Nov 22, 2022 at 23:51
  • Minor, but if it’s an Epson clone beyond reasonable legal constraints then check out the Epson FX-80 manual for the entire font laid out in large on a grid in the appendix. Sadly I can’t immediately find a copy online that isn’t behind one of those awful online manuals sites, with watermarks, terrible navigation and an entreaty to pay if you just want the PDF.
    – Tommy
    Nov 24, 2022 at 12:50
  • @Tommy - Thanks. Someone above included a link to the Epson MX-80 printer manual and it has an Appendix with the Character Grid. This Regular font would be so easy to do in Glyphs as the grid is the same width and height. I've done a wider spaced version to match my printouts, but the Regular grid is a good check and starting point for the symbols I have yet to add.
    – QuinGold
    Nov 24, 2022 at 17:33
  • @Tommy Epson's own website has a link to FX-80 user manual: files.support.epson.com/pdf/fx80__/fx80__u1.pdf
    – QuinGold
    Nov 24, 2022 at 18:03
  • And the FX-80 specifications from Epson: files.support.epson.com/pdf/fx80__/fx80__sl.pdf
    – QuinGold
    Nov 24, 2022 at 18:04

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