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A Presentation On Printer

A Presentation On Printer

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A Presentation On Printer

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  1. A Presentation OnPrinter Department of Computer Engineering, M. S. P. V. L. Polytechnic College, Pavoorchatram.

  2. Introduction • Printer is an output device. • This is used to take hard copies of any computer based application.

  3. Types of printer • Dot matrix printer • Ink jet printer • Laser printer

  4. Dot matrix printer • In this printer the characters are formed with the help of dots. • So this is called dot matrix printer.

  5. Dot matrix printer

  6. Dot matrix printer

  7. Types of Dot matrix printer • 7-pin printers • 9-pin printers • 24-pin printers

  8. Operation of 7-pin printer • The print head of the dot matrix printer consists of a column of 7 small needles. • Each needle can move freely.

  9. Cont.,

  10. Cont., • Each needle can be made to print a dot by means of a hammer action that forced the needle to come out and press the ribbon against the paper. • Standard characters are produced in a 5 x 7 dot matrix. (7 dots high and 5 dots wide).

  11. 5x7 dot matrix

  12. Cont., • The characters are printed column by column and not all at once. • For example to print the character T, initially pin number 1 is made to contact the ribbon.

  13. Cont., • Thus first column of the characters is got. • Then the print head is moved towards right and once again the pin 1 is made to contact the ribbon. • Thus second column of the character is got. Then the print head is moved to get the third column and so on.

  14. Cont., 1 2 3 4 5 1 2 3 4 5 6 7

  15. Parts of a Dot matrix printer

  16. Interface Connector Power supply Block diagram of Dot matrix printer Control electronics Front panel Switches and LED DIP switches Driver circuits Line feed motor LF mechanism Cooling fan Paper sensor Print mechanism Carriage motor Carriage movement control Print head control Print head Home sensor Temperature sensor Ribbon motor

  17. Dot matrix printer head mechanisms in action: Classical printhead mechanism is showed from the left side. The permanent magnet printer head mechanism you may see at right.

  18. Construction of a Dot matrix printer Power supply • Normally printers consist of Switch Mode Power Supply (SMPS). • This unit is used to convert the AC voltage to different DC voltage levels.

  19. Power supply +5V To control electronics, driver circuit SMPS -12V AC 230 V To Buffer To print head, paper feed motor, Carriage motor +24V

  20. Cont., Interface connector • Printers are connected to the computer through a 36 pin centronics interface cable or a 9-pin RS 232C serial interface cable. • The serial data from the computer is received and stored in the printers buffer RAM.

  21. Centronics Printer connector

  22. RS232 Connector

  23. Cont., • The Buffer RAM can store one line to one page depending on the size of the RAM.

  24. Printer Buffer RAM

  25. Cont., Control electronics • This unit contains an intelligent processor for controlling the functions of the printer.

  26. Cont.,

  27. Cont., Driver circuit • This unit is used to control the line feed mechanism, print mechanism and ribbon movements. • These mechanisms use stepper motors.

  28. Driver circuit

  29. Cont., • This circuit provides high current for driving these stepper motors. • Also it sends feed back signals to control electronics for monitoring the speed and displacement of these mechanisms.

  30. Cont., Front panel • This consists of a minimum three status lights (LED) and three soft touch switches. • The lights are used to give information about the status of the printer to the user.

  31. Front panel

  32. Cont., • Switches are used to give the control commands. • For example font selection.

  33. Cont., DIP switches • These switches are present in the interface card and are used to change the printer settings.

  34. DIP switches

  35. Printer setting change The settings that can be changed are • Printing of graphics and accented characters • Page length • Line spacing

  36. Cont., • Print quality • Auto line speed • Character set for different countries

  37. Sensors • These are used to keep the printer safe from abnormal conditions.

  38. Printer sensor

  39. Different Sensors Home sensor • This is used to detect whether the head carriage is in the extreme left margin. Paper empty sensor • This is used to signal when there is no paper in the printer.

  40. Cont., Temperature sensor • This is used to detect the abnormal timings used to fire the pins.

  41. Cont., Print mechanism • This contains two subsystems Carriage movement control mechanism • This moves the carriage bidirectionally by means of a stepper motor

  42. Carriage movement control mechanism

  43. Cont., Ribbon feed mechanism • This feeds the ribbon when the print head is printing

  44. Ribbon feed mechanism

  45. Features of Dot matrix printer • Both text and graphics can be printed • Printing cost is very low • Multiple copies can be taken with the help carbon papers

  46. Cont., • By increasing the number of pins from 7 to 9 or 24 the quality of printing can be increased. • It’s operating speed is slow.

  47. The End Thank you!