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Free, open-source Android printing for Epson inkjets connected to a router's USB print server.

Download Release 4 · Get started · Build from source · Hardware testing

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Printy lets Android send documents and photos to a USB printer through a compatible network print server. It includes an Android Print Service, so saved printers can appear in the native Print dialog, plus its own file picker and preview.

No accounts. No ads. No analytics. No watermarks. No paid unlocks.

Important

Early, experimental software. The owner now reports successful printing with Release 2 on an Epson L130 through an Airtel ZTE ZXHN F670L. Release 3 adds page selection and layouts while retaining that transport and encoder. The new layouts still need a physical print check; L120/L210 remain unverified on hardware. Software tests do not establish universal printer compatibility.

Downloads

Release	Version	What it contains	Status
Release 4	0.2.1	Keep screen on while printing; user-approved background printing allowance	Current experimental build
Release 3	0.2.0	Page ranges, odd/even selection, reverse order, 1/2/4 pages per sheet and sheet previews	Previous layout update
Release 2	0.1.1	Improved connection completion, corrected footer, copyable job details, bottom-of-page test marker	User reports working on L130/F670L
Release 1	0.1.0	Initial Android app, Print Service and standalone ESC/P2 encoder	Historical build with reported stalls

Each release includes an APK, a SHA-256 checksum, and a tagged source snapshot. These APKs are debug-signed development builds, not production-signed store releases. The downloads use the same certificate and application ID, so updates preserve saved printers.

See the changelog and verification notes for the differences and completed checks.

What you can do

Feature	Included
Print from other apps	Native Android Print Service and saved-printer discovery
Print a PDF or photo	System file picker, page preview and Gallery share-sheet support
Set basic options	1–99 copies, color or grayscale, portrait or landscape
Choose pages	All pages, custom lists/ranges such as 1, 3–5, odd/even pages and reverse order
Save paper	1, 2 side by side, or 4 pages per sheet, with a preview of the assembled sheet
Choose paper	A4, Letter and 4 × 6 inches, with a white margin
Save several printers	Name, numeric IPv4/IPv6 address, port, exact model and last-used time
Check a new setup	Three-step onboarding and a one-page test print
Follow a job	In-app progress, notifications, cancel and copyable job details
Avoid screen-timeout stalls	Keep Printy visible to keep the screen on during an active job; optional Android background allowance
Make it your own	Kotlin, Jetpack Compose, Material 3 dynamic color and a reusable JVM encoder

Printer and router compatibility

Profiles currently target Epson L130, L120 and L210, based on Gutenprint's model-80 geometry. L120 and L210 have not been physically tested. Similar Epson model names do not imply compatibility; other models are not advertised as supported.

You need:

• An Android phone or tablet running Android 8.0 / API 26 or newer.
• One of the listed Epson printers connected to a router or print server that already supports USB printer sharing.
• A reachable raw TCP printing endpoint, usually the router's LAN address on port 9100.
• The phone and print server on a network where they can reach each other.

Printy cannot add printer-sharing support to router firmware that lacks it. A reachable TCP port also cannot establish whether paper, ink or the attached printer is ready. The current protocol does not provide reliable jam/ink reporting through generic USB routers.

Why choose a printer model?

The model selects the command format and physical ink-head geometry. A router's raw port forwards bytes; it does not translate them into a universal printer language. Removing the selector would not make other Epson models or other brands compatible. Model detection could simplify setup where a server exposes that information. A future IPP Everywhere backend could support driverless printers across brands, alongside the existing Epson backend.

Get started

1. Download the APK from Release 4 and install it on your Android device.
2. Connect the printer to your router's USB port and enable printer sharing in the router's settings.
3. Open Printy. Enter the router's local IP address, select the exact printer model, and use port 9100 unless your print server specifies another port.
4. Load plain A4 paper and send one test page. Check the text, four colors, bottom marker and complete sheet ejection before printing a document.
5. For printing from other apps, open Android Settings → Printing → Printy and enable the service. Use the source app's Print action and select your saved printer.
6. Or tap Print a file in Printy, choose a PDF/photo, review the pages, set options and print.

The original test page placed all text in the top half of the sheet. Release 2 adds a marker near the bottom to distinguish complete raster output from a sheet that fails to eject.

Choose pages and fit two on a sheet

In Print a file, open a PDF and scroll to the options:

1. Under Pages to print, keep All pages, choose odd/even pages, or choose Choose pages and enter a list such as 1, 3–5. Numbers refer to the original PDF, starting at 1. Overlapping ranges print each page once, in document order.
2. Set Layout → 2 pages side by side. Printy selects landscape automatically; orientation remains adjustable. Choose 4 pages per sheet for a grid.
3. Use the preview arrows to review each output sheet. Pages go across, then down; the final unused spaces stay white. Reverse page order reverses the selected pages before grouping.
4. Choose copies, paper and color, then tap Print … sheets. Copies are collated; progress counts physical sheets.

These layout controls are in Printy's own file preview. Android's native print dialog keeps its own page controls, and Printy honors the PDF subset supplied by the spooler. This release provides single-sided layouts, without booklet reordering or automatic duplex printing.

If printing pauses when the screen turns off

Release 4 keeps the screen on automatically while Printy is visible and any job is active, including preparation, queued jobs and the connection-finishing wait. Normal timeout returns after the queue finishes, fails or is canceled. Dismissing a progress card does not remove this protection. This uses Android's standard keep-screen-on flag across supported phones.

For printing while manually locked or while using another app, tap Allow background printing on the home screen or preview before starting the job, then approve Android's request. If your phone still pauses, use Open app battery settings and set Printy's battery/background use to Unrestricted (the name varies by phone). The app refreshes the allowance status when you return.

The existing foreground service and CPU wake lock do not override Android Doze network restrictions. The requested exemption addresses those restrictions, but manufacturer policies still vary. Manual lock always remains possible. Keeping Printy visible is the fallback that avoids automatic timeout; no universal locked-screen guarantee is made. The OnePlus 13s report prompted this change; physical verification remains pending. Screen protection ends when transmission/connection finishing ends, since the router cannot confirm paper completion.

If a job stops partway through

• Cancel the active job in Printy and use the printer's Stop button to clear the stalled job. Avoid repeatedly submitting new documents into a stalled page.
• In Release 2, allow up to 90 seconds while the app displays “Finishing the connection.” Some print servers never close their side of a finished connection.
• Tap Copy job details before dismissing the job card. Include those details, the printer/router model, Android version and what appeared on paper in a bug report.
• Review the copied details before posting: they include the printer's local endpoint. Do not attach private documents, Wi-Fi passwords or credentials.

“Sent” describes transport delivery, not confirmed physical printing. A router can accept all bytes even if its USB printer is stalled. Canceling closes the connection, but data already buffered in the router or printer may still print. Partly sent jobs are never automatically replayed.

What changed in Release 2

• Corrects the model-80 job footer: restore NVRAM settings (LD) before job end (JE), matching Gutenprint's command order.
• Reads incoming replies while sending, then shuts down the output side and waits for the server before fully closing the connection.
• Allows a blocked write up to 120 seconds and keeps cancellation available during sending and connection finishing.
• Stops automatic connection probes to an endpoint after a print attempt for the rest of the app process. Status cards show the last known check.
• Adds copyable byte counts, elapsed time, footer-flush state and connection-ending details. Reply payloads and document contents are not recorded in those details.
• Adds a bottom-of-page marker and regression tests for connection completion, cancellation and reset behavior.

The owner subsequently reported that the app works well on the L130/F670L setup. Detailed geometry, media and failure-mode checks remain in the hardware checklist.

How it works

flowchart LR
    A[Print from another app] --> B[Android spooler]
    B --> C[Printy Print Service]
    D[File picker or share sheet] --> E[Preview and options]
    E --> F[Direct print service]
    C --> G[Shared job queue]
    F --> G
    G --> H[PDF raster strips]
    H --> I[Standalone ESC/P2 encoder]
    I --> J[TCP print server]
    J --> K[Epson USB printer]

Loading

Android app · app

The app owns profile storage, document import, previews, services, progress, notifications and transport. PrintPlan validates page ranges and groups source pages into output sheets before the socket is opened. Android's PdfRenderer renders at 360 DPI in 128-row strips, avoiding a full-resolution page bitmap. Each layout cell is clipped independently; preview and print use the same fit/rotation transforms. Photo import handles EXIF orientation and bounds decoded image dimensions.

Native Android jobs receive the PDF page subset supplied by the spooler; Printy does not apply the original page indices a second time. Native print margins are preserved without an extra inset. Landscape rotates content while the physical paper feeds short-edge first.

One queue prevents overlapping streams. Native jobs use the bound Print Service lifecycle; direct jobs use a foreground service. Started jobs interrupted by process death are not silently replayed.

Reusable encoder · escp-encoder

A plain Kotlin/JVM module with no Android dependencies. A row-based RasterSource feeds CMYK/grayscale conversion, serpentine error diffusion, two-bit drop packing, TIFF PackBits and software nozzle interleaving. EscpEncoder writes to any OutputStream.

This is a restricted implementation, not a full port of Gutenprint. It does not yet include its calibrated color/media curves, high-resolution adaptive weave or verified borderless modes. See protocol notes for geometry, commands and provenance.

Build it yourself

Use JDK 17 or 21, Android SDK platform 35 and build-tools 35.0.0. Set ANDROID_HOME, or point sdk.dir in an untracked local.properties at your SDK. The Gradle wrapper pins 8.11.1 and its distribution checksum.

git clone https://github.com/neerajjayesh/printy.git
cd printy
./gradlew :escp-encoder:test :app:testDebugUnitTest :app:lintDebug :app:assembleDebug

On Windows, use gradlew.bat. The generated APK is app/build/outputs/apk/debug/app-debug.apk. Android Studio can open the repository directly.

Run the standalone encoder tests without an Android SDK:

./gradlew -PencoderOnly :escp-encoder:test

Run PDF strip-rendering tests with a connected device or emulator:

./gradlew :app:connectedDebugAndroidTest

GitHub Actions builds the app, runs JVM tests and lint, and runs a separate emulator job. CI build artifacts are newly built debug APKs; their signing keys can differ from the APKs attached to releases. Keep your release signing key private and stable when producing future updates.

Verification so far

Check	Release 1	Release 2	Release 3
Encoder JVM tests	12 passed	13 passed	13 passed
App JVM tests	4 passed	9 passed	20 passed
Android API 35 rendering tests	Not run locally	1 passed in subsequent CI	6 passed in CI
APK signature	Verified	Verified; same certificate	Verified; same certificate
Android lint at local verification	0 errors	0 errors; 8 dependency-update suggestions	0 errors; 8 dependency-update suggestions
Physical printer test	L130/F670L stalls reported	User reports working on L130/F670L	New layouts await a physical check

The byte fixtures are derived from upstream reference commands, not captured from a successfully verified L130 print. Consult verification results, the Actions run for the relevant commit, and the hardware checklist before drawing broader conclusions.

Privacy

Printer profiles remain in app-private storage. Documents are copied to private cache because PdfRenderer requires seekable files; job-owned copies are deleted after completion, cancellation or failure. Unused import/preview files expire after 24 hours and are cleaned on startup. Import size is limited to 150 MB. Android backup is disabled.

No analytics, advertising SDKs, accounts or cloud print service are included. Printing uses an unencrypted local TCP connection, so use it on a trusted local network. Diagnostic details are copied only when you tap the button; Printy does not upload them.

Contribute and extend

See CONTRIBUTING.md. Hardware reports are particularly useful: record exact printer/router models and firmware, Android/app versions, paper, reproduction steps and a non-sensitive output sample.

To add another Epson model:

1. Find its entry in Gutenprint's src/xml/printers/escp2.xml and follow its model, baseline, ink and media tables.
2. Add an EpsonModel only if its command dialect, DPI, nozzle geometry, channel offsets and two-bit encoding match this backend. Different dialects need a separate strategy.
3. Add reference fixtures and raster-coverage tests. Extend paper/margin capabilities in both the encoder and Android discovery code.
4. Validate feed geometry, primary/gray ramps, channel alignment, page ejection and multi-page jobs on hardware. Record the evidence in the hardware checklist before advertising compatibility.
5. Preserve upstream attribution and license notices with every adaptation.

Roadmap

• Receive a successful L130/F670L user report following the connection fix.
• Page selection and 1/2/4 pages per sheet in Printy's preview.
• Complete detailed layout/media acceptance tests and validate L120/L210 on real hardware.
• IPP Everywhere backend for compatible driverless printers across brands.
• mDNS discovery where print servers advertise compatible endpoints.
• LPR transport with configurable queue names.
• Verified borderless photo profiles and calibrated color/media settings.
• Additional Epson model strategies, accessibility testing and localization.
• Direct photo/PDF printing through Android's share sheet.

License and acknowledgments

GPL-2.0-or-later. See LICENSE and THIRD_PARTY_NOTICES.md.

Command sequencing and model data are adapted from Gutenprint, particularly its ESC/P2 driver and model tables. Credit goes to Michael Sweet, Robert Krawitz, Charles Briscoe-Smith and the Gutenprint contributors. Porting C logic to Kotlin does not remove the upstream license obligations.

Printy is an independent community project and is not affiliated with Epson, ZTE or Airtel. Product names identify tested or targeted hardware.