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MLT-288 Service Manual

17

Chapter 4  Trouble-Shooting

4-1  Procedure for Repairs

When the printer is out of order, observe the phenomenon of the trouble carefully to specify what is the trouble
according to 4-2 “Guide to Repairs.”  Then, repair it according to the prescribed method.

* Phenomenon
Look for the phenomenon of the trouble in the column of “Phenomenon” in the following list.  In the case of
phenomena more than one, take up all applicable items.  This can specify hidden defects.

* Causes
Possible causes are listed as many as possible.  Assume possible causes, and specify the cause from the check
methods mentioned in the next column.

* Check Method
This mentions check methods to specify the cause of the trouble.

* Repair Method
Repair the failure according to the method mentioned in this column.

Repairs done according to the above-mentioned procedure can reduce wrong judgment and secure effective trouble-
shooting.

Summary of Contents for MLT-288

Page 1: ...LINE THERMAL PRINTER MECHANISM MODEL MLT 288 Rev 1 00 Newly issued on Sep 29 2000 Service Manual ...

Page 2: ...i REVISION Rev No Date Comment Rev 1 00 Sep 29 2000 Newly issued ...

Page 3: ...ovided with a line thermal head This printer has been developed for the output terminals for POS terminals measuring and analyzing equipment medical equipment communication data equipment and the like and is small sized as far as possible Small sized and light weighted printer High speed printing up to 420 dot line sec Clear printing with 8 dot mm high resolution Use of paper 58 mm in width Use of...

Page 4: ...aper Feed Mechanism Block 7 2 4 Connecting Terminal 8 2 4 1 Thermal Head Terminal 8 2 4 2 Motor and Sensor connector 9 Chapter 3 Disassembling and Reassembling 10 3 1 Tool List 10 3 2 Procedure for Disassembling 10 3 3 Procedure for Reassembling 10 3 3 1 Procedure for Reassembling Printer Body 11 3 3 2 Head SP ASSY Reassembling Procedure 16 Chapter 4 Trouble Shooting 17 4 1 Procedure for Repairs 1...

Page 5: ... off lightly dirt stuck on the surface of heating elements with a cotton swab soaked in ethanol or the like 5 Activating the dewed thermal head is likely to damage the head If dew is present on the head dry it thoroughly before printing operation 6 Feeding Paper Feed paper in the head up condition Cut the front edge of paper straight Do not insert paper with its front edge fluffed or bent When the...

Page 6: ... 8 5V Vdd DC4 75 5 25V Max Approx 1 7A Max Approx 2 4A Max Approx 0 5A Ave Approx 0 3A 58 0 1 mm 60 72mm Nippon Seishi Co Ltd TF50KS E2C 0 49N or more 0 78N or more 6 million lines 15 million lines 50 million pulses or more 50 km or more Temperature 0 45 C Humidity 35 85 Temperature 20 60 C Humidity 10 90 6G Frequency 10 55Hz in three directions perpendicular to the machine for one hour 60G 11ms 6...

Page 7: ... Operational Principle The construction and operational principle of four blocks other than the frame and motor blocks in the above mentioned six mechanism blocks are described in the following 2 3 1 Power Transmission Mechanism Block This mechanism block is located at the left side of the printer Motor drive is to transmitted to the platen through the motor gear fixed to the motor gear the 1st re...

Page 8: ...ion significantly This head up sensor is used to control such cases Operating the head up lever activates the head up sensor fixed to the right side of the frame 2 Paper sensor This is a sensor to detect the presence absence of paper Activating the head when paper is not set is likely to damage the head or decrease the duration significantly This paper sensor is used to control such cases Head up ...

Page 9: ...l print data input from SI are transferred to the shift register in synchronization with CLOCK and stored in the latch register by the LATCH signal When the gate is turned ON by the head activation signal print commands STB1 to 6 the heating element corresponding to the stored print data is activated and this heat prints on paper VH 384 dot 1 STB 6 STB 1 LACH S1 CLOCK TH Vdd G2D LATCH SHIFT REGIST...

Page 10: ...as follows 3 Print data and print location Data No 1 to 384 of 384 bits transferred by SI are printed on the location shown in the following figure STB No Elements No Number of dots STB 1 1 64 64 2 65 128 64 3 129 192 64 4 193 256 64 5 257 320 64 6 321 384 64 Paper feed direction Roll paper Printing surface Data 1 2 3 4 383 384 DATA IN Printer mechanism Motor ...

Page 11: ... Feed Mechanism Block For the paper feed mechanism the platen that is the core of the paper feed mechanism rotates being driven by the power transmission mechanism Paper is supplied from the rear side of the printer and transferred to the upper part again through between the platen and head Then the paper is pressed to the platen by the head and is sent as the platen rotates Heat sink Cam of head ...

Page 12: ...minal is composed of two connectors Details are described in the following No 1 2 Function Thermal head Head up sensor Paper sensor Motor Number of pins 24 9 Type FFC Cable Pitch 1mm 51021 0900 Molex Recommended mated connector 52806 2410 Molex 53047 0910 53048 0910 Molex 2 4 1 Thermal Head Terminal The arrangement of thermal head cables and the function of each terminal are as follows 1 Terminal ...

Page 13: ...s follows Pin No Pin name Remarks 1 B 2 A Motor 3 B 4 A 5 Photo interrupter collector 6 Photo interrupter emitter cathode Paper sensor 7 Photo interrupter anode 8 Head up sensor output Head up sensor 9 Head up sensor output Pin layout of motor and sensors connector Sensor connector circuit diagram Paper sensor Head up sensor 9 8 7 6 5 4 3 2 1 ...

Page 14: ... leave parts screws or others used for maintenance work in the printer 6 In handling the print head do not use gloves that are easy to generate static electricity 7 In disassembling and reassembling work check cables and cords for damage or defects and do not lay them facibily 3 1 Tool List Screwdriver No 0 Pincette Mini radio plier Oil brush Mini nipper 3 2 Procedure for Disassembling For disasse...

Page 15: ...by a fitting screw M2 x 3 3 Incorporate the head up sensor to the right side of the frame assembly Set the head up sensor in the direction and fix it by a fitting screw M1 7 x 3 5 Caution In incorporating check the leaf of the head up sensor for deformation loose fitting and cracks Frame ASSY Mounting screw M2x3 Motor ASSY Head up sensor Mounting screw M1 7 x 3 5 Rear Rear ...

Page 16: ... bottom surface of the frame assembly Caution Be careful not to break the cover of lead wires in incorporating work 5 Fix lead wires for the motor assembly with binding strap for lead wires not to get loose Rear Paper sensor Frame ASSY Binding strap Motor ASSY Rear ...

Page 17: ...en into the hole on the right side of the frame assembly and then inserting it into the hole on the left side Next align the profile shape of the platen gear with the left side metal shaft of the platen and press it on Insert the head up lever on the right side metal shaft of the platen and assemble with No 2 E ring Ø5 platen insert hole Gear pivods Rear Platen Frame ASSY Rear E ring No 2 Head up ...

Page 18: ...so that the smaller gear comes to the upper side Incorporate the 3rd reduction gear so that it may engage with the 2nd reduction gear and platen gear Caution In incorporating be careful about the direction so that the larger gear comes to the upper side 9 After assembling each gear apply furoyl G 943 to the surface of 3rd reduction gear Rear 1st reduction gear 2nd reduction gear 3rd reduction gear...

Page 19: ...Do not touch the print surface of the head with bare hands 11 Insert the FFC cable for the head SP assembly into the chassis hole Slightly bend the head SP at two locations near the center and fit it onto the frame assembly Secure by tightening the four mounting screws M1 7 x 3 5 starting from the center hole Head SP ASSY Frame ASSY Rear Rear Head SP ASSY Projection section Mounting screw M1 7x3 5...

Page 20: ...the motor This is the end of reassembling work of the printer body 3 3 2 Head SPASSY Reassembling Procedure 1 Align the head SP with the two projections on the head assembly and insert Secure with two mounting screws M1 7 x 2 This completes the assembly of the head SP ASSY Rear Frame ASSY Mounting screws M1 7x8 Head SP Head ASSY Mounting screws M1 7x2 ...

Page 21: ...n in the following list In the case of phenomena more than one take up all applicable items This can specify hidden defects Causes Possible causes are listed as many as possible Assume possible causes and specify the cause from the check methods mentioned in the next column Check Method This mentions check methods to specify the cause of the trouble Repair Method Repair the failure according to th...

Page 22: ...Check if foreign matters stuck on thermal head Measure power supply voltage with tester or oscilloscope Check if dirt stuck on thermal head Check if paper that meets specification is used Repair method If out of rating correct power supply circuit Connect connector correctly Replace thermal head assembly If out of rating correct power supply circuit Replace thermal head assembly Wipe foreign matte...

Page 23: ...power supply circuit If lead wire broken renew motor assembly If supply voltage is normal replace motor assembly Set paper correctly Remove foreign matters Replace damaged gear If supply voltage is normal replace motor assemly Connect connector correctly Replace sensor assembly Connect connector correctly If sensor is normal replace sensor assembly Cause Motor connector Terminal connection poor Po...

Page 24: ...9 600304 00 REDUCTION GEAR 3 1 1 10 600305 00 PLATEN GEAR 1 1 11 500278 00 HEAD SP 1 1 12 100092 00 HEAD ASSY 1 1 16 200001 00 MOTOR ASSY 1 1 20 200002 00 PE SENSOR ASSY 1 1 23 200003 00 HEADUP SW ASSY 1 1 25 H560001 10 CABLE TIE T18S 1 1 26 27 28 29 30 31 F16417 035 SCREW No 0 PHT BT 1 GUIDELESS M1 7x3 5 5 5 32 F01817 03 SCREW No 0 PH 1 M1 7x3 1 1 33 F01917 08 SCREW No 0 PH 1 M1 7x8 1 1 34 F15917...

Page 25: ...MLT 288 Service Manual 21 Chapter 6 Disassemble Drawing MLT 288 disassemble drawing 23 31 36 6 25 20 5 10 8 7 9 34 11 31 4 31 33 16 32 12 1 ...

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