Craden Peripherals DP8 technical manual Mechanical Adjustments 5.4.1 Printhead Gap

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5.4MECHANICAL ADJUSTMENTS 5.4.1 Printhead Gap

Too large a gap causes light print and missing dots. Too small a gap causes ribbon smear.

1.Open the cabinet, raise the carriage with the lift ring and remove the ribbon cartridge.

2.Hold the ribbon shield at its corners between the shield face and shield base. Raise the ribbon guide plate and push the shield down and slide it to the right side to remove it.

3.Lower the carriage. Insert a narrow .015" (.38 mm) feeler gauge between the platen (printing surface) and printhead nose from the side of the printhead. Insure that the feeler is flat against the platen and completely under the printwires (not under the gap wheel or behind the printwires). The .015" feeler should just fit without raising the printhead but a slight resistance should be felt as the feeler slides below the printwires.

4.If the gap is incorrect, slightly loosen the two larger head screws on either side of the printhead that fasten the gap plate to the printhead. (Use a 5/16” wrench to hold the mounting nuts). The gap changes as these screws are loosened so only loosen them enough to be able to move the plate.

5.Decrease the gap by pushing the printhead down against the feeler. Increase the gap by rotating a screwdriver blade in the slot between the gap plate and the printhead Insure that the gap plate is centered around the printhead nose and tighten the screws. Recheck the gap per step 4.

6.Replace the ribbon shield by raising the carriage, sliding the shield from the side between the carriage and the ribbon guide plate until the shield slot is centered. Gently push the shield up until it snaps into place.

7.Mount the ribbon and use 95 FUNCT to print (See 3.8) and check print quality. Adjust the NORMAL and CQ DARKNESS parameters (see 5.2).

Insert the feeler gauge from the side of the printhead. Be sure the feeler gauge passes under the printwires only. (Front roller and input guide removed for clarity)

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Contents Airport HIGHWAY, PENNSAUKEN, NJ R I P H E R a L S R P O R a T I O NRevision ALL Record of ChangesPages Affected Operation DP8 & DP9 Technical Manual Table of ContentsTheory of Operation MaintenanceMajor Assembly Illustrations & Parts Lists TroubleshootingRecommended Spare Parts Recommended Service Tools Environment & Standards Document CharacteristicsPhysical Characteristics InterfaceInstallation Procedure Operation Ribbon Cartridge Loading ReshipmentKeypad & Display Panel Keypad OperationDisplay Operation Document Insertion ConfigurationConfiguration Category Press Remarks Printer ParametersDisplay Display Remarks Communication ParametersOverride Parameters Diagnostics Power Up Diagnostics Service ParametersSelf Test Enhanced DiagnosticsError Conditions Document Jam Carriage FaultAscii Command SummaryHex Command ProgrammingESC R ESC HESC K ESC LPrint Commands Stops double height print DC3 Low Density Graphics CommandsHigh Density Graphics Commands Display CommandsDP XE DJ KB BZ BA Configuration CommandsStatus and Keypad Commands Drivers Installing Craden Drivers on Windows 95 orAscii MeaningUsing Printer Resident Device Fonts Installing Craden Drivers on Windows NT, 2000 or XPInstalling Craden USB Drivers on Windows NT, 2000 or XP Input Buffer Operation Writing to the Printer LCD DisplayInterfacing FunctProblem Solving Interface Signals & CablesPin Signal Description Printer Pin PC-25 Pin PC-9 Pin SignalNo Printing or Light Printing Carriage Fault or No Carriage MotionRollers Run at Power-Up or After Document Ejected No Document MotionTheory of Operation Overview Carriage Drive AssemblyDocument Drive Assembly Switching Power SupplyStepper Motor Drivers Keypad/Display AssemblyMain Printed Circuit Board Microprocessor SystemPhase a I0A I1A Phase B I0B I1B Current U20 15 a Stepper Motor Drive CircuitCharacter Printing Keypad and Display Refer to Schematic #72135Printhead Drivers SensorsPrinthead Drive Circuit I LSensor Cleaning MaintenanceLubrication and Cleaning 5.1.1 Lubrication Document Feed Roller CleaningHarsh, abrasive cleaners Printhead CleaningDocument Print Area Cleaning Cabinet Exterior CleaningElectrical Adjustments Service Parameter SET-UP ProcedureMechanical Adjustments 5.4.1 Printhead Gap Ribbon Shield Removal / Replacement Ribbon Shield Face Inspection Rear Document Roller Spring Force Carriage Drive Belt TensionDocument Drive Belt Tension Carriage Shaft Cam and Shaft RackAuto Alignment Gate Height Auto Alignment Gate RampCabinet Replacement ProceduresFront Document Roller Spring Force Auto Alignment Skew Sensor CalibrationDisplay Power Supply PCBSensor PCB KeypadDocument Drive Belt Document MotorPrinthead Carriage Drive BeltDefective Keypad TroubleshootingBasic Troubleshooting Procedure No DisplayNo Carriage Motion Defective SensorNo Document Motion Print Quality Symptom Condition RemedyNo Print or Light Print Interface Inoperative Missing DotsErratic Document Feed or Mispositioning Erratic Character Spacing or False Document JamsUse this flow chart to assist in troubleshooting Diagnostic FlowchartDescription PART# Recommended Service ToolsRecommended Spare Parts Printer Diagram All assemblies not ending in X are used both on DP8 and DP9 DP8 & DP9 Assembly TreeDWG REV. C Page Page Page Page Page Page Page