CUPS Dyesub Backends

This is my personal to-do list for printer-related tasks, encompassing both changes to Gutenprint ( and the CUPS backends (

IDTask Type  ascCategorySummaryStatusLast Edited
 476 Bug ReportShinko CHC-S2145 s2145 hangs on subsequent requests Closed2013-07-16 Task Description

The first request succeeds, but subsequent requests hang when trying to talk to the printer.

I suspect what's going on here is that the response buffers we're posting are simply too small and the printer loses its mind.

564Bug ReportMitsubishi CP-D70 familyD70 fails to print on Raspberry Pi systemsResearching2018-02-26 Task Description

We get failures when sending the printjob to the printer, with libusb reporting USB timeouts at random places.  There seems to be no consistency to when a transfer fails.  Using a hub makes this worse.

I have an additional two reports of a RPi3 failing USB transfers to a D80 when there is no ethernet cable plugged into the interface!


The K60/EK305 appears to work okay.

 484 Bug ReportCanon Selphy CP/ES CP-10 hangs after first print Closed2014-01-28 Task Description

Not sure why. Perhaps a USB sniff under Windows would be helpful.

 525 Bug ReportMitsubishi CP-D70 family Output on CP-D70 is way too dark Closed2015-07-23 Task Description

This suggests we need to apply a correction curve to the raw 16-bit data sent to the printer.

Uncertain if user was using the ICC profile.

Unfortunately it'll probably take some careful analysis of printing calibration targets to come up with an appropriate correction factor.

 526 Bug ReportCanon Selphy CP/ES CP900 not printing properly. Closed2014-10-30 Task Description

it prints the first page successfully, then keels over.

 531 Bug ReportMitsubishi CP-D70 family Mitsu K60 and Kodak305 don't work properly Closed2016-09-01 Task Description

There's something funky with the backend.

 545 Bug ReportCanon Selphy CP/ES Figure out how to make the CP820/CP910/CP1000/CP1200 ac ...Closed2017-04-21 Task Description

It would be *really* nice if we could figure out a way to ditch the component Y'CbCr output and use native YMC, but it's likely that only Canon ultimately knows if that's possible, and how.

 553 Bug ReportCanon Selphy CP/ES Back-to-back CP1200 prints hang the printer Closed2016-12-03 Task Description

User repors that back-to-back prints cause the printer to hang.  This is with the stock USB backend that relies on standard flow control.

Fixing this will first require printing stuff back-to-back under Windows and sniffing it to see if there's any flow control in use.  Bleh

 560 Bug ReportMitsubishi MedSci P95: Failure to parse printjob when 'clear memory' is e ...Closed2017-02-12 Task Description

The problem is that two commands of different length use the same 2-byte prefix.  To distinguish between them we'll need to read the third byte, but only in that case as there are some commands that are only 2 bytes.


Or re-architect the command parser to handle this without extra hacks.

 562 Bug ReportMitsubishi CP-D70 family Quality problem with the D70 family image processing li ...Closed2017-03-19 Task Description

It's most obvious when printing something with a deep black; you'll see it bleed past a bit.

It's worse in Fine, better in SuperFine/UltraFine.


580Bug ReportCanon Selphy CP/ESDetect when on battery power and handle it gracefullyNew2017-04-11 Task Description

User reported the CP800 failed to print when on battery power, turns out one of the status fields changed causing us to fail.  I believe that's resovled for the older SELPHY CP models, but the newer ones (including the CP790) and the ES series are likely to have a similar problem.

Not sure what can be done about this without getting the battery and experimenting...

588Bug ReportMagicard familyRegistration/Alignment issue with Black planeNew2018-01-04 Task Description

K extraction appears to work well, but when printing there's a registration problem.  The black layer appears to print several pixels higher than the color layers.

I'm not sure if this is something that needs a fixed offset applied, or is something that can vary printer-printer.

 589 Bug ReportMagicard family Fix 8bpp->6bpp color scaling Closed2018-01-04 Task Description

Right now we just shift the color data over by 2bits.  It looks like that's naive; it looks like we need some sort of gamma-aware 8->6 mapping on a per-channel basis.  This may require Gutenprint to spit out RGB data, and we perform the YMC conversion at the same time we apply gamma?  (not unlike the Mitsu D70 family..)

The printer's "gamma curve" settings don't seem to have any major effect.

It's also possible that my printer's head is just plain shot (there's already a bad row of pixels..), and that everything is actually fine.

 530 Feature RequestMitsubishi CP-D70 family Reverse-engineer color scaling/dithering algorithm Closed2016-10-07 Task Description

Mitsubishi CP-D70, D707, K60, D80, and their siblings (Kodak 305, Fuji ASK300) all rely on the driver to dither/scale their output data based on an unknown algorithm.

Figure out what this is, so that these printers can be properly supported.

 517 Feature RequestCommon Code Support multi-page print jobs Closed2014-01-20 Task Description

The backends should handle multi-page jobs by splitting it into individual prints. This is presumably handled by concatenating multiple spool files together...

The entire structure of the backends are designed around single-page operation.

Many of the backends are smart enough to tell when a page ends, but some aren't. Extend the backend core so that it can handle this when the backend supports it.

 485 Feature RequestKodak 1400/805 Add support for the Kodak 805 Closed2013-07-18 Task Description

The 805 uses an identical spool format as the 1400, and is phyiscally an updated model.

Obtain a sniff of a print under Windows, and update the backend to work as appropriate, or write a new spooler if the format is radically different.

 486 Feature RequestKodak 6800/6850 Add support for Kodak 6850 Closed2013-07-27 Task Description

The Kodak 6850 uses an identical spool format. Somehow obtain sniffs of the printing sequence and update the spooler as necessary.

 488 Feature RequestKodak 1400/805 Add support for setting tone curves Closed2013-10-18 Task Description

The raw format and command structure are already known. Add backend support for setting tone curves, not unlike what s2145 backend provides.

 489 Feature RequestShinko CHC-S2145 Update s2145 'read tone' command to return binary blob Closed2013-07-09 Task Description

The 'read tone' command returns formatted, human-readable output. Fix this to use a similar binary blob as the 'write tone' command expects.

 492 Feature RequestKodak 6800/6850 Add support for setting tone curves Closed2013-10-18 Task Description

The Kodak 6800 is supported by Kodak's "visual profiler" tool; get a USB sniff of what it does and use that to add support to the backend.

 493 Feature RequestShinko CHC-S2145 Use 'unique string' in lieu of serial number Closed2013-07-25 Task Description

The Shinko S2145 doesn't return a serial number in its USB descriptor. Unfortunately this means there is no way to distinguish between multiple printers on a single system.

The printer does have a user-configurable string; the backend allows for this to be queried and set. Perhaps we could add the ability to use this string in lieu of the serial number?

 494 Feature RequestCommon Code Improve detection to include printer status Closed2014-02-18 Task Description

When you have more than one printer in the system, how about ignoring the ones that are busy when trying to service a print job?

For printers that support multiple media types, it would be handy to be able to return which media the printer has loaded, so we
can more intelligently route print jobs.

This is probably beyond the scope of a CUPS backend, but may be handy for standalone operation.

Just a WIBNI.

 499 Feature RequestCanon Selphy CP/ES Better error detection & handling Closed2014-01-30 Task Description

The remaining chunk of the patch set Ake Koomsin sent over considerably improves error detection, handling, and recovery from the CP-XXX handler. (The other models are TBD)

Wade through the patch set to make sure everything relevant is integrated.

(FWIW, this is a lot easier now that the backend is unified; it simplified the code quite a bit)

 511 Feature RequestMitsubishi CP-D70 family Investigate the Mitsibishi CP-K60DW Closed2015-07-23 Task Description

Outwardly it appears nearly identical to the CP-D70DW. Spec-wise it seems the same (even using the same media!) except for a lower print speed.

Find out if it speaks the same spool file format.

 512 Feature RequestDNP/Citizen Enhance DS40/DS80 backend Closed2013-12-17 Task Description

There's now a backend for the DS40/DS80 that will handle things like multiple copies and whatnot.

Verify it works with both a DS40 and an DS80.

Enhance it so it properly reads the printer status, buffer state, and whatnot to ensure we're good to submit a new print job.

 518 Feature RequestCanon Selphy CP/ES Recover from Error conditions (ES models) Closed2014-03-12 Task Description

There's a special command the driver sends to clear the printer's error state.

We know this for the CP-series, but none of the ES-series.

The backend supports this just fine now, but we don't know how the ES models recover.

520Feature RequestOther printersInvestigate Sony UP-CR20L aka DNP SL-20Assigned2018-12-29 Task Description

Sony sold their printer line to DNP, which rebranded these two models.

Investigate their Spool format, and find out if they need an intelligent backend.

521Feature RequestOther printersInvestigate HiTi 720L/750L and 510L/520L/525L, P310W an...New2018-09-21 Task Description

P310W is consumer model.

Rest are workhorse kiosk printers, it's currently the cheapest per-print, 300dpi.

Gutenprint seems to support no HiTi models at all.

Early investigation into these models shows that the spooler format is some sort of funky compressed format -- and the data actually sent to the printer is ratehr different.

So no progress will be made without direct access to one or more HiTi printers.

 522 Feature RequestKodak 6800/6850 Better status reporting Closed2014-06-04 Task Description

Need to detect media type, number of remaining prints, error conditions, and whatever else is possible given our lack of documentation of the printer internals.

(Maybe decompiling the driver would help?)

 523 Feature RequestCommon Code Proper media/ribbon status messages Closed2016-08-21 Task Description

CUPS has a standard reporting mechanism for attributes, including media/ribbon/etc levels. The general syntax is:

ATTR: foo=bar[,baz,etc]

There's also the notion of state that can be reported in a unified manner:

STATE: +media-empty [reasontext]
STATE: -media-empty


1) Altering backends to report media empty using this mechanism
2) Alter backends to report remaining media, if known, using this mechanism.

For further details:

 524 Feature RequestOther printers Figure out Mitsibishi CP-D9550's USB comms. Closed2015-07-23 Task Description

It looks like this printer needs a backend.

Also, the '-S' suffixed models probably use a different comms mechanism.

 528 Feature RequestMitsubishi CP-D70 family Investigate the CP-D80DW Closed2015-07-23 Task Description

At first blush it looks like the "professional" version of the K60DW-S with higher-speed operation.

Should be straightforward.

 529 Feature RequestOther printers Investigate Kodak 8800 Closed2016-10-18 Task Description

The 8800 seems to be related to the Kodak 9810

 534 Feature RequestOther printers Write backend for S6145 Closed2015-12-06 Task Description

This is a sibling of the Mitsu D70 family, but differing in that it uses Shinko's own protocol that's similar to the other Shinko models.

It will need its own backend; however the backend needs to deal with color scaling/dithering. I have binary x86/x86_64 libraries that implement this algorithm, but that is not acceptible for use with GPL code.

535Feature RequestOther printersWrite backend for Kodak 8810 and 7000/7010/7015New2016-09-08 Task Description

The 8810 is also known as a Shinko CHC-S1845-5A.

It appears closer to the S1245 mechanically, but S6245 programically.

The 7000/7010/7015 models are Shinko CHC-S1645-5A/5B/5C, respectively.

Probably not worth wasting any time on unless someone steps up with docs and hardware.

537Feature RequestOther printersWrite backend for Shinko DP-1045 and Kodak D4000New2015-08-26 Task Description

They're the same thing, an 8" wide duplex printer. No support in Gutenprint yet.

538Feature RequestDNP/CitizenAdd support for DS80DXRequires testing2018-10-02 Task Description

It has all the joy of the DS80, but also supports sheet-fed simplex and duplex operation. It's a veritable mess to support cleanly.

 541 Feature RequestMitsubishi CP-D70 family Validate Mitsubishi CP-D90 support Closed2018-05-20 Task Description

It looks like it's an evolution of the D70 family, with one critical exception -- it appears as if the color/thermal compensation is performed in the printer instead of the driver!

543Feature RequestOther printersIntestigate Color Sony MedSci modelsNew2017-03-23 Task Description

 UP-DR80MD, UP-DR25MD, UP-DR23MD, and so forth.

 544 Feature RequestDNP/Citizen Investigate and support new RX1HS Closed2016-10-07 Task Description

DNP's introduced the RX1HS to replace the RX1.  I'm told it's the same hardware, but requires different media.

Initial investigation shows it's added some features that were first introduced in the DS620.  (iSerial support, maybe more).  Backend changes will likely be minimal, but Gutenprint may require a tweak to expose any new features.

Further work will have to work until I get documentation or access to a printer.

 546 Feature RequestCommon Code Extend Gutenprint's option infrastructure to allow for  ...Closed2016-09-09 Task Description

The work's done, but it's not merged yet.

 547 Feature RequestCommon Code Add printer icons to Gutenprint Closed2016-10-13 Task Description

*OPIcon Manufacturer: "...."

*OPIcon ModelName: "...."

The data is UUEncoded/Base64 64x64 PNG or an SVG image.


I see printers.xml gaining a reference to the image files, and the PPD generation code reading the image, encoding it, and shoving it into the PPD.  It's a minor thing, but nice to have.


548Feature RequestShinko CHC-S6145Add support for Sinfonia CHC-S6145-5A (aka CS2-c)New2017-11-24 Task Description

It's a card-sized variant of the CS2.  89mm cards of various widths.

 551 Feature RequestMitsubishi CP-9xxx family Add CP-9600, CP-9800, CP-9810 support to CP-9550 backen ...Closed2016-12-03 Task Description

They're all closely related, so this is the right thing to do.

 552 Feature RequestCanon Selphy CP/ES Write network backend for CPnP printers Closed2019-01-30 Task Description

The 'selphy_go' code showed how to detect CPnP models and send JPGs over to be printed..

Using the CP900, I discovered how to send raw YMC data over CPnP.  This means we can write a native CPnP CUPS+Gutenprint backend for that model.

Unfortunately we won't know if the newer selphyneo models support non-jpeg CPnP printing -- The Windows driver uses WSA/WSD and Macs appear to use AirPrint.  The only way to find out is to write it first.

 554 Feature RequestCanon Selphy CP/ES Get USB IDs for Canon SELPHY CP820 Closed2017-03-27 Task Description

They're needed by the 'canonselphyneo' backend, and I've been unsuccessful in scrounging them up. 

 555 Feature RequestMitsubishi MedSci Investigate Mistubishi P93 and P91 Closed2017-02-10 Task Description

Now that the P95 is in solid shape, I don't imagine that the other models would pose much of a problem.

556Feature RequestSony UR-DP150/200status queries and flow controlNew2016-12-19 Task Description

It would be really nice if we could figure out how to query the UP-DR200's printer status, media counts, flow control, etc etc.

557Feature RequestOther printersInvestigate Sony DPP-FP30New2017-03-23 Task Description

And other members of that consumer printer family.  Not sure if they're still relevant commercially.

558Feature RequestOther printersInvestigate new Sinfonia S3 (CHC-S2245)New2018-05-13 Task Description

Replacement for the S2145, it's main fature is high capacity (900 print) media.

Initial investigation implies it may require host-side image processing, not unlike the S6145.

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