Editing Apple LaserWriter

{{Infobox computer peripheral
| name         = Apple LaserWriter
| image        = [[File:Laserwriter.jpg|250px]]
| caption      = Apple LaserWriter (1985)
| manufacturer = Apple Computer, Inc.
| type         = Laser printer
| release date = March 1985
| 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)
| power        = 760W maximum, 115V/60Hz
| model        = M0180
}}

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:'''
# Drum charging to -600V
# Laser exposure creating latent image
# Toner development using magnetic brush
# Transfer to paper via corona wire
# Thermal fusing of toner to paper
# 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):'''
{| class="wikitable" style="width:50%; text-align:center;"
! 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 ===

{| class="wikitable" style="width:90%; text-align:center;"
|+'''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 ==
<pdf>File:Apple LaserWriter Printers Volume I.pdf</pdf>

The complete Apple LaserWriter service manual is available on the [[:Category:Apple Service Source|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]]

{{Navbox-AppleVintageAccessories}}

[[Category:Apple Vintage Accessories]]