Apple LaserWriter

Apple LaserWriter
Apple LaserWriter (1985)
Manufacturer	Apple Computer, Inc.
Type	Laser printer
Discontinued	February 1988
Price	US$6,995 (1985 retail)
Interface	LocalTalk (RS-422), RS-232 serial
Compatible	Macintosh, Apple II, PC (via RS-232)
Dimensions	11.5" H × 18.5" W × 16.2" D
Weight	77 lbs (35 kg)
Model	M0180
Power	760W maximum, 115V/60Hz

The Apple LaserWriter was Apple Computer's first laser printer, introduced in March 1985 at a retail price of US$6,995. The LaserWriter utilized the Canon LBP-CX print engine and incorporated Adobe PostScript Level 1, making it capable of printing complex vector graphics, scalable fonts, and high-resolution bitmaps at 300 dots per inch. The printer contained a Motorola 68000 processor running at 12 MHz (clocked at 11.16 MHz), making it more powerful than the 8 MHz Macintosh computers it served. Combined with Aldus PageMaker software and the Macintosh's graphical interface, the LaserWriter became a cornerstone of the desktop publishing revolution.

Technical Specifications

Physical Specifications

• Dimensions: 11.5" H × 18.5" W × 16.2" D (292 × 470 × 411 mm)
• Weight: 77 lbs (35 kg)
• Operating temperature: 50°F to 90°F (10°C to 32°C)
• Humidity: 20% to 80% non-condensing
• Acoustic noise: 50 dBA operating, 40 dBA standby

Performance

• Print speed: 8 pages per minute
• Resolution: 300 × 300 dpi
• First page out: Approximately 30 seconds
• Engine life: 300,000 pages rated
• Duty cycle: 3,000 pages per month recommended

Power Requirements

• Input voltage: 115V AC ±10%
• Frequency: 60 Hz
• Power consumption: 760W maximum
• Current draw: 6.3A maximum
• Heat output: 2,599.2 BTU per hour

System Architecture

Processor and Memory

The LaserWriter contained sophisticated computing hardware that exceeded many contemporary personal computers:

Central Processing Unit:

• CPU: Motorola MC68000
• Clock speed: 12 MHz crystal (operating at 11.16 MHz)
• Data bus: 16-bit
• Address bus: 24-bit (16 MB addressable)

Memory Configuration:

• ROM: 512 KB mask ROM
• RAM: 1.5 MB total DRAM
  • 512 KB workspace RAM for PostScript interpreter
  • 1 MB frame buffer for page rasterization

• RAM type: 150ns DRAM chips
• Memory expansion: None (fixed configuration)

Controller Board Design

The LaserWriter's controller board employed a streamlined design using Programmable Array Logic (PAL) chips rather than discrete logic:

• Logic implementation: Monolithic Memories medium-scale integration PALs
• Address decoding: PAL-based memory management
• Timing control: PAL-generated signals for DRAM refresh and video timing
• Bus interface: Direct 68000 bus connection to memory and I/O

This design contrasted with competitors like HP LaserJet, which used numerous Texas Instruments 74-series discrete logic gates plus custom LSI chips.

PostScript Interpreter

The LaserWriter was the first commercially available printer to include Adobe PostScript:

PostScript Implementation:

• Version: PostScript Level 1
• Licensor: Adobe Systems
• Royalty: Initially 5% of list price ($350 per unit)
• Language features: Complete programming language with stack-based execution
• Graphics capabilities: Vector graphics, Bézier curves, arbitrary transformations
• Font handling: Type 1 outline fonts with hinting

Interpreter Performance:

• Rasterization: Real-time interpretation during printing
• Complex pages: Could require several minutes for full rasterization
• Memory management: Dynamic allocation for fonts and graphics

Print Engine

Canon LBP-CX Engine

The LaserWriter utilized Canon's LBP-CX laser print engine, shared with the HP LaserJet:

Engine Specifications:

• Technology: Laser xerography (electrophotographic)
• Photosensitive drum: Organic photoconductor (OPC)
• Laser type: Semiconductor laser diode
• Developer system: Single-component toner
• Fusing: Heat roller at approximately 180°C

Print Process:

1. Drum charging to -600V
2. Laser exposure creating latent image
3. Toner development using magnetic brush
4. Transfer to paper via corona wire
5. Thermal fusing of toner to paper
6. Drum cleaning and discharge

Consumables

• Toner cartridge: Apple M0180 or HP 92285A (cross-compatible)
• Yield: Approximately 3,000 pages at 5% coverage
• Drum life: Integrated with toner cartridge
• Paper tray: 250-sheet capacity letter/legal cassette
• Manual feed: Single-sheet bypass for envelopes/transparencies

ROM Fonts

The LaserWriter included 13 built-in PostScript Type 1 fonts in its 512 KB ROM:

Font Families

Times (4 styles):

• Times-Roman
• Times-Italic
• Times-Bold
• Times-BoldItalic

Helvetica (4 styles):

• Helvetica
• Helvetica-Oblique
• Helvetica-Bold
• Helvetica-BoldOblique

Courier (4 styles):

• Courier
• Courier-Oblique
• Courier-Bold
• Courier-BoldOblique

Symbol (1 style):

• Symbol (mathematical and Greek characters)

These fonts were licensed from Linotype and became industry standards. Each font included complete character sets with proper kerning pairs and hinting for optimal 300 dpi output.

Interfaces and Connectivity

LocalTalk Interface

The primary connection method used Apple's LocalTalk networking:

LocalTalk Specifications:

• Physical layer: RS-422 differential signaling
• Data rate: 230.4 kbps
• Topology: Bus with daisy-chaining
• Maximum nodes: 32 devices (practical limit ~16)
• Maximum distance: 1000 feet (305 m) total bus length
• Connector: DB-9 female on printer
• Protocol: AppleTalk protocol stack

LocalTalk Connector Pinout (DB-9):

Pin	Signal	Direction
1	Frame Ground	-
2	RxD+	Input
3	RxD-	Input
4	TxD+	Output
5	TxD-	Output
6-9	Not connected	-

RS-232 Serial Interface

A secondary interface provided PC compatibility:

RS-232 Specifications:

• Connector: DB-25 female
• Data rate: Up to 19,200 baud
• Data format: 8 bits, no parity, 1 stop bit
• Flow control: XON/XOFF or hardware (RTS/CTS)
• Protocol: PostScript commands or Diablo 630 emulation

Interactive PostScript Mode

The LaserWriter featured an interactive PostScript interpreter accessible via RS-232:

Terminal Connection:

• Settings: 19,200 baud, 8-N-1
• Access command: Type "executive" to enter interactive mode
• Capabilities: Direct PostScript programming, diagnostics, font management
• Error messages: Displayed on terminal for debugging

Paper Handling

Input Specifications

• Standard cassette: 250 sheets
• Manual feed: Single sheets
• Paper sizes: Letter, Legal, A4, Executive
• Paper weight: 16-24 lb bond (60-90 g/m²)
• Media types: Plain paper, transparencies, envelopes

Output Specifications

• Output tray: 250-sheet capacity face-down
• Stacking: Offset stacking not supported
• Duplex: Manual duplex only

Diagnostic Features

Self-Test Page

The LaserWriter could print a comprehensive self-test page containing:

• Printer serial number
• ROM version
• Installed RAM
• Page count
• Font samples
• PostScript version
• Print engine status

Status Lights

Three LED indicators on the front panel:

• Ready: Solid green when ready to print
• Paper: Amber when paper low or jam
• Service: Red for errors requiring service

Error Reporting

• PostScript errors: Sent to host via LocalTalk or RS-232
• Engine errors: Indicated via status lights
• Diagnostic mode: Accessible via service switches

Common Issues and Maintenance

Preventive Maintenance

Regular Service Intervals:

• 50,000 pages: Clean corona wires, check paper path
• 100,000 pages: Replace transfer corona assembly
• 200,000 pages: Replace fuser assembly
• 300,000 pages: Major overhaul recommended

Cleaning Procedures:

• Toner vacuum: Use only toner-rated vacuum
• Corona wires: Clean with provided brush monthly
• Paper path: Wipe with lint-free cloth
• Exterior: Damp cloth with mild detergent

Common Failures

Typical Failure Modes

Component	Symptoms	MTBF	Repair
Fuser assembly	Poor toner adhesion, wrinkled pages	200K pages	Replace unit
Corona wires	Light print, streaking	100K pages	Clean or replace
Pickup rollers	Paper feed failures	100K pages	Clean or replace
DC controller	No power, intermittent operation	5-7 years	Board-level repair
Scanner motor	Horizontal lines, distorted print	300K pages	Replace motor assembly

Power Supply Issues

The LaserWriter's power supply was prone to capacitor failures:

Common Symptoms:

• Intermittent power
• Failure to maintain ready state
• Random resets during printing

Capacitor Replacement:

• Replace all electrolytic capacitors as preventive maintenance
• Use 105°C rated capacitors for longevity
• Typical service life: 5-7 years

PostScript Programming

Basic Commands

The LaserWriter accepted PostScript commands for direct control:

Example PostScript Code: ``` %!PS /Times-Roman findfont 12 scalefont setfont 72 720 moveto (Hello World) show showpage ```

Memory Management

• VM (Virtual Memory): 512 KB available
• Font cache: Dynamic allocation
• Save/restore: Stack-based memory management
• Garbage collection: Automatic when VM exhausted

Font Downloading

Additional fonts could be downloaded to RAM:

• Maximum downloadable fonts: Limited by available RAM
• Font format: Type 1 or Type 3 PostScript
• Persistence: Lost on power cycle
• Management: Via PostScript commands

Service Information

Service Mode Access

Internal DIP switches provided service functions:

• SW1: Continuous self-test
• SW2: Suppress startup page
• SW3: Diablo 630 emulation mode
• SW4: Reserved

Test Points

The DC controller board included test points for:

• +5V DC logic supply
• +24V DC motor supply
• -24V DC bias supply
• High voltage (measure with appropriate probe)

Adjustment Procedures

• Print density: Potentiometer on DC controller
• Registration: Mechanical adjustment of laser unit
• Fuser temperature: Thermistor calibration

Compatibility

Operating System Support

• System 2.0 or later: Full LaserWriter support
• System 6.x: Optimal performance
• System 7.x: Supported through 7.5.5
• Apple II: Via AppleWorks and appropriate interface card
• MS-DOS: PostScript drivers or Diablo 630 emulation
• UNIX: lpr with PostScript support

Application Support

Applications with native LaserWriter support:

• Aldus PageMaker 1.0 and later
• MacWrite
• MacDraw
• Microsoft Word 1.0 for Macintosh
• Adobe Illustrator
• Ready,Set,Go!
• QuarkXPress (later versions)

Service Manual

The complete Apple LaserWriter service manual is available on the Apple Service Source page.

LaserWriter Plus

The LaserWriter Plus, introduced in January 1986, expanded on the original with:

• ROM: Increased to 1 MB
• Fonts: 35 built-in fonts (22 additional font styles)
• Price: US$6,798
• All other specifications remained identical

Additional fonts in LaserWriter Plus:

• ITC Avant Garde (4 styles)
• ITC Bookman (4 styles)
• Helvetica Narrow (4 styles)
• New Century Schoolbook (4 styles)
• Palatino (4 styles)
• ITC Zapf Chancery (1 style)
• ITC Zapf Dingbats (1 style)

Related Pages

• Apple Desktop Bus
• LocalTalk