LITHOGRAPHIC PRINTING OFFICE

Lithographic Printing Office is one of the most important units of Survey of Bangladesh. It is an industrial production unit and plays a vital role in map production. Survey  of  Bangladesh prints various kind of maps, charts and forms with modern printing technology.

Lithographic Printing Office no longer uses the heavy cumbersome stones but instead use light, flexible metal ( Ps plate, Thermal plate) plates. Now modern technics are used in lithographic plate preparation and printing.

Map production chain starts with taking of aerial photographs/satelite images and is completed through the process of plotting, editing and cartographic work in the process of map printing.In map printing, the original impressions are in 4 colors i.e. YMCK( Yellow, Magenta, Cyan and Krisp/Black) as film or soft copy are used.   

Pre Printing Process:

To start map printing process it is need to making plate. There are a two types of plate making job. One from positives to plate and another from cartographic map data to plate.  The first noe process became obsilute. Now a days Lithographic printing office is using Computer to Plate (CtP) technology in stead of making film positives, it will directly make plates of desired colors from computerized cartographic map data. This CtP technology enhances the quality and productivity of map printing.     

Plate Making Section : There are two plate making sections in Lithographic Printing Office. One is Helio section and another is Plastic section.

Helio section : In helio section there are two CtPs (Computer to Plate) machine (1)  Screen Plate Writer, (2) Optotech One Plate Writer.

(1)  A) Screen Plate Writer (CtP)  (Country of Origin China)

Processor Type : Offline Processor

Plate Type : Thermal Plate

Laser Type : Thermal , Laser resolution of the files output from the HQ RIP.

Resolution : 2400 dpi

Production Speed : 20 Plates / Hour

Plate Loading/Unloading System : Automatic

Plate Thickness : 0.20 - 0.40 mm

Max. Plate Size : 825 mm X 1030 mm

Min. Plate Size : 740 mm X 925 mm

Construction Type : Internal Drum Image Setters

Related Software: HQ RIP ( Raster Image Processing)

RPI Specification: PDF, EPS, TIFF, PS, SHP Format

Fig: Screen Plate Writer (CtP) 

B) Processor : GRAFMAC

Type : Offline

Speed : 60-200 cm/min

Tank Content : 35 Littre for chemical

Operation System : Automatic

Fig: Processor 

(2) A) Optotech One Plate Writer Country of Origin Italy

Processor Type : Offline Processor

Plate Type : Thermal Plate

Laser Type : Thermal , Laser resolution of the files output from the Studio RIP.

Resolution : 2540 dpi

Production Speed : 20 Plates / Hour

Plate Loading/Unloading System : Automatic

Plate Thickness : 0.20-0.40mm

Max. Plate Size : 825mm X 1030mm

Min. Plate Size : 740mm X 925mm

Construction Type : External Drum Image Setters

Related Software : Studio RIP ( Raster Image Processing)

RPI Specification : PDF, EPS, TIFF, PS, SHP Format

Fig: Optotech One  Plate Writer (CtP) 

B) Processor : SIRIO EXPORT 85

Type : Offline

Speed : 60-200 cm/min

Tank Content :40 Littre for chemical

Operation System : Manual

Fig: Processor 

Printing Process :

There are two technologies for transferring ink from the image area of the plate to the paper .One technique is direct printing in which ink is directly transferred from the plate to the paper and other technology is offset printing in which the ink is first transferred from the plate to a rubber cylinder and than from the robber on the paper.

Map Paper : Generally Lithographic printing office uses various kind of paper such as:

Map Lithu Paper: 25 ̋ x 35 ̋, 80-110 gsm, 0.8-1.0 mm

Offset Paper:  23 ̋ x 36 ̋, 80-100 gsm, 0.8-1.2 mm   

Mat Paper: 25 ̋ x 37 ̋, 80-130 gsm, 1.2-1.4 mm

Kornafully Paper:  (27 ̋ x 34 ̋ )or (17 ̋ x 27 ̋ ), (80-120) gsm or (40-60) gsm, 0.8-1.2 mm  

Printing Machine: There are four printing presses in Lithographic Printing Office (2- machines are very old). They are functioning well. These are given bellow.

1) KBA Rapida 105 (2016)

Max. Substrate  720*1050 mm

Min. Substrate  360*520 mm

Max. Speed      16,000 sh/h

Max. Speed Option 17,000 sh/h

Min. Speed   

Substrate Standard 0.06-0.7 mm

Substrate Board Option   up to 1.5 mm

Substrate Foil     up to 0.7 mm

Fig: KBA Rapida 105

2) Lithrone GL 240 (2013)

Paper Size

Max. Paper size: 720*1030 mm

Min. Paper size: 360*520 mm

Paper thickness: 0.04 to 0.8 mm

Max. Speed Option 16,000 sh/h

Printing Area

Max. Printing area: 710*1020 mm

Plate Dimensions: 800*1030 mm

Blanket Dimensions: 920*1040 mm

Cylinder Dimensions

Plate cylinder: Ǿ300mm

Blanket cylinder: Ǿ300mm

Impression cylinder: Ǿ300mm

Fig :  Lithrone GL 240

3) Heidelberg (1974)

Paper Size :

Max. Paper size: 605*740 mm

Min. Paper size: 360*520 mm

Paper thickness: 0.04 to 1.2 mm

Max. Speed Option 13,000 sh/h

Printing Area

Max. Printing area: 600*720 mm

Fig: Heidelberg

4) Ronald Record (1992/2002)

Paper Size :

Max. Paper size: 740*925 mm

Min. Paper size: 360*520 mm

Paper thickness: 0.04 to 1.2 mm

Max. Speed Option 13,000 sh/h

Printing Area

Max. Printing area: 720*905 mm

Fig: Ronald Record

With satisfaction to note that Map printing is the final step of production chain of map making. At present Survey of Bangladesh enjoys state of the art printing capacity. In addition to serving the needs of survey of Bangladesh, the printing services are also rendered to other government department like Bangladesh Metrological department, Bangladesh Air Force, Bangladesh Rail Way etc.