MH series

MH
MH
Series information
Type	Two drum
Status	Active
Launched	2022

Resources

Tutorials

The following user created tutorials apply to the MH series.

Maintenance

Replacement parts

Name	Part no.	Stock	Unit
Feed tire	`035-14303` `021-14301`	2 / riso	Paper feed
Feed tire	The two matching rollers in the 1st paper feed—the outer one is the "scraper" (feeds multiple sheets in) and the inner one is the "pickup" (separates the top sheet). Each is an inner plastic core and outer tire (this is the part for the tire). The inner (pickup) roller should use OEM, the outer (scraper) roller can use generic—generic tires tend to be eccentric (egg-shaped) and a smaller diameter than the originals. The RP uses 3 rollers, two of which are tires on a proprietary core, but the third roller requires a solid feed tire.
Stripper pad	`019-11833`	3 / riso	Paper feed
Stripper pad	The stripper pad puts upward force and friction on the multiple pages that are fed into the pickup roller, so that the teeth of the tire only propel the top sheet into the riso. It is the rubber part that wears the fastest and must be replaced regularly for stable paper feed. Very old risos may use a different stripper unit, which takes an older stripper pad type (a thin square), otherwise this part is universal. An alternative grey stripper pad is listed under part no. `019-11834`—it uses a harder material, which is meant to last longer and be better for heavier paper stocks.
Feed roller core	`023-12306` `021-14302`	1 / riso	Paper feed
Feed roller core	The plastic core of the feed rollers (the feed tires are stretched around these) contains a one-way bearing, which allows the paper to be pulled freely through the 1st paper feed by the 2nd paper feed and press sections. This bearing wears down over time, which will either decrease the feed power or cause the roller to drag on the rest of the system. Replacement cores ship dry, and will need oiling.
Elevator shaft gear	`023-12215`	1 set	Paper feed
Elevator shaft gear	Two of these gears transport the elevator up and down. When the elevator is damaged the teeth will snap off these plastic gears—a 3 mm roll pin punch is needed to replace them.
Flaw bearing	`600-50057`	2 / riso	Paper feed
Flaw bearing	Four of these are used in the elevator, they are very delicate and will break apart if the elevator is damaged.
Lock plate B	`030-14130`	1 set	Paper feed
Lock plate B	A pair of these is responsible for locking down the side guides on metal feed trays. If the guides are forced apart while locked, these pieces will break.
Separator needle (Z+)	`023-21002` `024-21038`	1 / riso	Paper ejection
Separator needle (Z+)	This needle is responsible for peeling paper off of the drum in the ejection process—if damaged (or improperly calibrated) paper will stick to the drum more and/or the needle will leave a drag mark down the center of the print. In the rare occurrence of catastrophic drum failure inside the riso, the separator needle will often smash against the surface of the drum (or catch under clamp)—as a result of (1) being adjusted too close to the drum, or (2) a component of the drum raising too high off the surface of it. Usually this harms the drum more than the needle, but sometimes the needle shatters too. The riso can operate without the needle (so long as the rubber hose is kept out of the paper path)—but the paper will stick to the drum more frequently. There are two versions of this needle—the sharper, earlier needle is part no. `023-21002`, while the newer snub-nosed needle is part no. `024-21038`—they can be used interchangeably, so long as they are properly recalibrated. The separator needle position should always be calibrated after changing the needle.
Exit belts (Z+) (two-drum)	`629-00004`	1 set	Paper ejection
Exit belts (Z+) (two-drum)	Exit belts transport paper out of the riso—usually a suction fan pulls air down through holes in the belts to hold the paper to them while a dedicated motor powers the belts. In two-drum machines the exit belts are a set of 3 thin belts with holes running along them. Note that these belts appear very similar to one-drum belts, but they are a slightly different length and are not interchangeable. As they wear, they will stretch out and slip on their rollers—paper will become stuck in the exit area (particularly larger sheets of heavier stocks). Belts can be tested by dragging them with a fingertip—all the belts should move together—if individual belts slip, it's a sign that all should be replaced.
Midfeed belts	`629-00003`	1 set	Paper ejection
Midfeed belts	Two-drum machines also have a set of 4 shorter belts (with holes in them), which transport the paper between the two drum positions. When testing these belts, all 4 should feel locked when trying to drag them with a fingertip.
TPH gear	`612-10010`	2 / riso	Master making
TPH gear	This small plastic gear is part of the TPH pressure system—when it fails the riso will no longer be able to lift the thermal printhead, and will throw a `T19` or `P19` error. This is a critical part—when it breaks the riso will be fully non-operable until it is replaced. They break every 3–7 years. Instructions for replacement are available at: Thermal-pressure motor lock (TPH gear)
Transport bands (Z+) (two-drum) (feed side)	`628-00002`	1 set / riso	Master removal
Transport bands (Z+) (two-drum) (feed side)	A set of 4 small rubber bands (o-rings) which are used to transport the stencil off of the 1st drum position (paper feed side) and into the disposal box. When they break, the stencil will become more easily jammed between the disposal rollers. Note that the transport bands for the 1st drum and 2nd drum sides of two-drum machines are different and not-interchangeable (they are also different from one-drum transport bands). These parts can often be easily replaced with generic o-rings of a similar (or slightly smaller) size. The Japanese size for these is listed as 2×130 (2 mm cross section and 130 center circumference) or S40 (a JIS designation). The closest ISO size is A0380 (1.8 mm cross section, and 38.7 mm inner diameter). In imperial sizes these bands have a 1/16" cross section—the closest commonly available size is ⌀ 1⅝ in (outer diameter)—however in practice, slightly smaller o-rings (down to ⌀ 1⅜ in) have been more effective. All of the bands in the set should be replaced at the same time.
Transport bands (Z+) (two-drum) (ejection side)	`628-00001`	1 set / riso	Master removal
Transport bands (Z+) (two-drum) (ejection side)	A set of 4 small rubber bands (o-rings) which are used to transport the stencil off of the 2nd drum position (paper ejection side) and into the disposal box. When they break, the stencil will become more easily jammed between the disposal rollers. Note that the transport bands for the 1st drum and 2nd drum sides of two-drum machines are different and not-interchangeable (they are also different from one-drum transport bands). These parts can often be easily replaced with generic o-rings of a similar (or slightly smaller) size. The Japanese size for these is listed as 2×112 (2 mm cross section and 112 center circumference) or S35.5 (a JIS designation). The closest ISO size is A0345 (1.8 mm cross section, and 34.5 mm inner diameter). In imperial sizes these bands have a 1/16" cross section—the closest commonly available size is ⌀ 1½ in (outer diameter)—however in practice, slightly smaller o-rings (down to ⌀ 1¼ in) have been more effective. All of the bands in the set should be replaced at the same time.

Specifications

	Print area	DPI	Year
MH9350	A3	600	2022
MH9450	Ledger	600	2022

Usage

There are 31 places printing with MH duplicators (7% of all active places).

MH9350

Duplikat Press 🇬🇧Edit-et-p0llux 🇫🇷Gaada 🇬🇧Herr & Frau Rio 🇩🇪KMD RISO 🇳🇴Kulturbüro Basel 🇨🇭Manchester School of Art 🇬🇧PageMasters 🇬🇧Pamflett 🇳🇴Risolab des Possibles 🇫🇷Risotto 🇬🇧

MH9450

667 Studio 🇨🇦Ann Arbor District Library Secret Lab 🇺🇸Bird in Hand Press 🇺🇸Bromstad Printing Co. 🇺🇸Calipso Press - New York 🇺🇸Center for Book Arts 🇺🇸CopyCat Studio 🇨🇦Current Press 🇺🇸EWU 4D Lab 🇺🇸Emily Carr University of Art + Design 🇨🇦Flatlands Press 🇺🇸Maloquio press 🇲🇽Perfectly Acceptable Press 🇺🇸Pratt Institute Imaging Center 🇺🇸Rathaus Press 🇺🇸Risolve 🇺🇸SimSumStudio 🇺🇸Space Type 🇺🇸Spina/Novoa 🇺🇸Split Arrow Print House 🇺🇸

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A map of the 31 places printing with MH duplicators—as listed in the Atlas.