Ricoh printheads

[picoj]

Hi everyone,

I was wondering if anyone had any experience with Ricoh printheads. I have recently become obsessed with nozzle level recirculation and am on a mission to drive their printheads myself or at least have full control over one include drive waveform.

I'm thinking about the MH2910F to begin with, I recently bought one of these used and am eagerly waiting for delivery.

As expected, there's basically no public information available about any of the Ricoh printheads so i'm a little bit of a loss where to begin though that's half the fun. Pinout and electrical drive details is one aspect but also recirculation flow rates, pressures etc is another.

I have been thinking about buying some Chinese drive electronics to start with. It seems like BYHX support the GEN4 however I haven't yet been able to find any sellers which stock this head driver board: https://www.byhx-china.com/index.php?m= ... 104&id=180. Looking at some videos of the controller software it seems like this should do what I want. They even offer a waveform editor tool.

An alternative would be to try and buy a complete printer which uses GEN4 heads such as the Ricoh RI100. It might take some time for one of these to come up for sale used however and i'm also worried that given the low price of the printer, the heads in it might use some sort of encryption (similar to Epson).

Anyway just wanted to see if anyone had any experience or advice to offer and I will be happy to document my progress as I go.

[picoj]

I've been researching ink handling equipment for use in full recirculation and ended up buying a complete system from a supplier on Alibaba.

I got a dual (inlet and outlet) pressure regulation system as well as a all the tanks and pumps needed etc.

I was planning on making this myself for testing just with a basic gravity feed, and some level sensors to refill the tank but the price was significantly less than I anticipated. When I thought though everything required in a full system it seemed like a good deal to save time. Any details I can share if anyone's interested.

Back on the printhead side I have been trying and failing to find a supplier of G4 electronics. I think that the G4 heads are not very commonly used which is strange because looking on internet archive the recirculating one I want with large drop sizes only appeared on their site in the last 2 years. The other models do go way back though. Still it seems like the G5 is mostly what everyone is using along with G6. One supplier actually suggested G5 might stop getting manufactured soon which could have also been a sales tactic to use their preferred epson goodness.

Anyway so I haven't decided if I go with the G5 MH5421F or look at another brand that is more commonly used. I was actually looking at the Starfire SG1024 as an alternative and came across what appears to be a complete user manual with all needed information to drive it. not sure if anyone has come across this before but it was a very interesting read.

https://www.ekkotech.com/file/spectra%20sg1024.pdf

The starfire is actually a very interesting head because it can be completely disassembled. All it's components are modular.

[chacha]

I also have the intention of making an ink circulation system, mainly to facilitate the heating of the ink material. At present, I am developing the nozzle of Xaar1002/1003 series, and I have completed most of the hardware design work, and I am still debugging the firmware code. Unfortunately, I do not have the waveform editing tool of this type of printhead, so I can only control the nozzle pressure by voltage.
Why did you develop this circulation system?

[picoj]

Hi Chacha,

I'm not sure about the electrical interface of the XAAR1002/3 or your electronics to drive it but I can make one suggestion which may be of use

Previously I made a single nozzle drop on demand system using a stainless piezo disc and a 3D printed housing. To drive it I used a power amplifier and a arbitrary waveform generator.

You can trigger the signal generated externally, and the bandwidth of the OPA549 is reasonably high which should probably be sufficient for inkjet frequencies but i'm not sure how quickly you are able to trigger the function generator externally. I was only using it to a few hundred hz.

Anyway perhaps it could be good for prototyping but you probably want a DAC along with an amplifier in the long term.

There's also a company called Apex Engineering that make some very nice modules designed to drive the analog portions of various inkjet heads:
https://www.apexanalog.com/applications ... inter.html

In terms of my application, I'm mainly interested in water based inks with high loadings of soluble components that dry quickly so unfortunately the XAAR1002/3 won't work for me. It seems like XAAR recently recently a new head designed for water based ink but i'm also interested in the stainless steel construction of Ricoh's heads for chemical compatibility.

[picoj]

A quick update on my project.

My fluid handling system is on it's way to me but i'm having some issues with the shipping because apparently it has some fluids still in it. Unfortunately I organised the shipping myself separately. I think it will need to be returned to the manufacturer and drained.

I think I have settled on a method to drive the head electrically. I was trying to decide between BYHX control boards and some from another vendor. Ideally I would reverse engineer the protocol to the headboard from BYHX which appears to use an LVDS link for communication but I would need to first build a printer around the BYHX electronics, make needed measurements, then make the electronics to drive it. Given my limited time wasn't a project I really wanted to take on unless I needed to.

The alternative was to buy some electronics from a well known vendor which I won't name. Their solution cost about as much to get started with as a new car but comes with a SDK and full support etc. Just not really an option for me because of the cost.

So I was thinking about the problem and doom scrolling on alibaba as I have been doing lately and I came across this module which is actually designed to drive Ricoh GEN5 heads:
https://www.apexanalog.com/products/mm04.html

The data sheet even gives a pinout for the Ricoh head which I have just not been able to find anywhere.

It even comes with a eval board and has a very nice gui which you can use to program waveforms etc.
https://www.apexanalog.com/resources/pr ... m04gmu.pdf

And it's available on Mouser!!! It's not in stock so may take a little while to get but it's really ideal for my purposes. Initially I will probably control it via serial but it has passthrough for all the digital bit signals so eventually I will drive it with a micro or a PYNQ board if I need the speed.

So I have ordered these and will wait for them to arrive.

I did want to upload this list that took me forever to find for anyone working with Ricoh GEN5 heads in the future. When trying to by the MH5421F a lot of sellers on Aibaba at least kept saying that it was actually a GEN6 head. They were mistaken but it's not nearly as common as the other non recirculating heads. This is a complete list of all GEN5 heads with their part number.

I was also very curious to find out the flow path of fluid in the different GEN5 heads. This video is of a head where the nozzle plate has been taken off. I was very confused because even non-recirculating GEN5 heads have 2 fluid connectors have an inlet and an outlet for each color. it turns out the inlet > outlet path is a common passage I guess for keeping solids in suspension and flushing / cleaning when needed. I'm still a little confused however because my recirculating head seems to have 2 inlets and 2 outlets so I still don't totally undertsand it.
https://www.youtube.com/watch?v=ao_edhz ... ggerRj_007

Anyway I hope to have my complete system up and running in the next month at least for testing.

Hopefully this helps anyone else on the same path in the future.

[Wonko]

Oh, wow. That is a pretty good setup for, um, still 2.500 Euros, but better than sinking the cost of a car... . Looks like a very easy entry into these kind of heads!

[bsnbipen]

That an awesome project. Thanks for sharing. I have some questions regarding your project.

1. What kind of controller are you trying to using in your printer for motion? How do you plan to sync the motion with jetting?

2. What kind of ink are you planing to use?

[picoj]

Yeah it's definitely a bit pricey for hobbyists but still can save a lot of time if you have the budget. I figure also it might save me going though one or two printheads during development so that's another factor though used and junk printheads are a lot cheaper than new. I'm just very time poor these days.

In terms of how to drive motion, timing, etc, I have some linear motors I bought used with high resolution encoders that I plan on using for scanning back/forward. I have a parker MX80L linear motor with 0.1um encoder which is probably overkill but anyway I drive it with an odrive controller.

This video isn't mine but I have basically the same setup:
https://www.youtube.com/watch?v=47cUBAB ... artholomew

I'm planning on feeding the encoder signal into a PYNQ-Z2 fpga dev board then use the FPGA core in combination with python code running on the arm core. For anyone not familiar with the PYNQ project it runs on some Xilinx FPGA's which have an arm core and run linux as well as a FPGA which can do realtime processing while attempting to keep high level code in python. So i'll do something like copy a row of print data at a time into a buffer from python, command the odrive to move one pass via python, then the FPGA can send the print data to the apex board asynchronously with the correct timing as the encoder pulses come in. I think this is how most printers work anyway. I've played around with PYNQ a little but never anything this complicated so not sure about the details yet but that's the general idea.

To start with though i'm going to be doing just basic jetting for a while to test the compatibility of my ink. I also have some thoughts to make a DIY drop watcher but probably this isn't required.

In terms of my ink / application I might not talk about this very much sorry. Though all my ideas usually turn to dust i'm hoping it will become more than a hobby at some point. In like likely event my idea doesn't work, i'll definitely share it but it's a chemistry process thing that's probably not too interesting anyway for most people

Still I wanted to document my build of the printer side of things so others could replicate it in the future. It's so frustrating that there's such little inkjet info out there because the technology has so many applications but is just not approachable for most hobbyists. I've been thinking putting everything on Github once I have everything up and running.

It will be a few weeks at least before my driver comes as it is on backorder but I'll update this thread once I have something.

[chacha]

That an awesome project. Thanks for sharing. I have some questions regarding your project.

1. What kind of controller are you trying to using in your printer for motion? How do you plan to sync the motion with jetting?

2. What kind of ink are you planing to use?

At first I planned to use a grating bar and use each pulse of the encoder to trigger the jet, but then I felt that this was not necessary as long as I could maintain constant motion. I'm not on the same project as him, but I wanted to talk a little bit more about it.
In addition, ink is also very interesting to me. I want to make UV ink by myself, but I don't know where to start.

[picoj]

Yes I suppose the feedback mechanism sort of depends on your motion system. With stepper motors you always know pretty much where you are any any time within the mechanical limits of your setup. The motion control system of my linear motor is somewhat limited. I just command it to go to a position and reading it's position in real time is not fast enough so I think I need some other method to synchronize the firing pulses. A stepper motor probably would have been simpler really but the linear motor is just what I already have and is also very fast and backlash free.

On the subject of UV ink/resin my suggestion would be to start by reading some MSDS's. Usually they will give you an idea of most of the active ingredients in any resin or ink as they are usually hazardous. It's really just 3 or 4 ingredients that are needed for a basic resin, I previously made my own resin for micro-stereolithography in a research context. Usually it's a photo initiator, monomer, polymer depending on what properties you're after and a light blocker at least in 3D printing, not sure about inkjet though. I think optimising the ink for jetting would be far far harder than making your own resin. I've been thinking how to make a drop watcher for this purpose myself but that will be a whole separate journey. Sourcing these ingredients is a little harder though and also it seems like hitting a specific viscosity could make it harder. I usually use sigma-aldrich to buy supplies but you have to be associated with as business to open an account. Alternatively you can usually source these from suppliers on Alibaba though that can be a process.

For example here is the MSDS for one random 3D printing resin and you can see it's ingredients:
https://photocentricgroup.com/wp-conten ... -Resin.pdf

Often they won't say the photoinitiator used but really any free radical photoinitiator such as TPO would work.

I'd also strongly suggest reading some academic papers on the subject of UV resin formulation, there are many. For example here is one paper which could server as a good introduction:
https://www.researchgate.net/publicatio ... ithography