US3472352A

US3472352A - High speed serial printer

Info

Publication number: US3472352A
Application number: US761896A
Authority: US
Inventors: Nicholas Kondur Jr
Original assignee: Burroughs Corp
Current assignee: Unisys Corp
Priority date: 1967-06-28
Filing date: 1968-09-16
Publication date: 1969-10-14
Anticipated expiration: 1986-10-14
Also published as: FR1572747A

Description

Oc t. 14, 1969 N. KONDUR, JR

HIGH SPEED SERIAL PRINTER 3 Sheets-Sheet 1 Original Filed June 28, 1967 INVENTOR. NICHOLAS KUNUUR, JR. W

ATTORNEY.

N. KONDUR, JR

HIGH SPEED SERIAL PRINTER Oct. 14, 1969 s Sheets-Sheet 2 Original Filed June 28, 1967 mvmnm NICHOLAS KONDURJR. BY m A TTORNEX Oct. 14, 1969 N. KONDUR, JR 3,472,352

HIGH SPEED SERIAL PRINTER Original Filed June 28, 1967 3 Sheets-Sheet :s

I N V EN 'I"O,R. NICHOLAS KONDUR, JR.

4 AT T'ORNE Y United States Patent Int. Cl. B41j 1/52 US. Cl. 197-49 Claims ABSTRACT OF THE DISCLOSURE The disclosure embodies a continuously rotating print drum, an endless timing belt driven in synchronization with and along the drum, a single hammer having a home position, and a clutch including the belt, operable to couple the hammer to the belt to initiate operation of a line of printing. A control system for the printer includes a signal from an information input source or computer, and a switch which responds to the presence of the hammer at home position, the computer signal and the switch mutually controlling engagement of the clutch. The switch is also responsive to a predetermined movement of the hammer travel preliminary to the start of a line of printing whereby to control hammer printing operation mutually with a pulse generator which operates in synchronization with the print wheel and timing belt.

This application is a continuation of Ser. No. 649,641, filed June 28, 1967, now abandoned.

SUMMARY OF THE INVENTION The invention resides in the provision for a high speed serial printer, of a continuously rotating print drum with which a single impression means or hammer is synchronized and travels along the drum, operating in response to input information. Synchronization is eifected by a timing relationship between the drum and the traveling hammer such that the hammer travel may be initiated at any time providing that the hammer is in home position. A scanning operation of a pulse generator which is also synchronized with the drum and hammer is initiated by a switch responding to a predetermined initial travel of the hammer from the home position of the latter to the first column of type on the drum.

The principal object of the invention is to provide an improved high speed serial printer of the type in which a traveling hammer moves along a print line striking selected print type on the periphery of a continuously rotating drum and return to home position.

It is a particular object of the invention to provide a printer of the above mentioned character in which initiation of travel of the hammer from rest at its home position can be effected any time after return of the hammer to home" position.

In the drawings:

FIG. 1 is a perspective view of a high speed serial printer, embodying features of the present invention;

FIG. 2 is a fragmentary plan view;

FIG. 3 is a fragmentary end view;

FIG. 4 is a fragmentary vertical sectional view;

FIG. 5 is a vertical sectional view;

FIG. 6 is a horizontal sectional view partly in elevation, taken along the line 6-6 of FIG. 5;

FIG. 7 is a detail sectional view of a timing belt of the machine;

FIG. 8 is a detail plan view of a permanent magnet and switch of a control system; and

FIG. 9 is a diagrammatic illustration of the printer and a control system therefor.

3,472,352 Patented Oct. 14, 1969 With reference to the drawings, the printer comprises, in general, a base 10, a print drum 12, a single print hammer 14, and a print hammer carrier 16. The drum 12 and the carrier 16 are mounted on the base 10, the drum being mounted for rotation about a horizontal axis and the carrier being mounted forwardly of the drum for the purpose of carrying the hammer along a print line 17 parallel to the drum axis.

The drum 12 is atfixed onto a driven shaft 18 which is journaled in uprights 20 of the base 10, and the drum is driven by an electric motor 21 through a toothed drive connection or timing belt 22. The drum 12 is driven continuously by the motor 21 to move print elements or type on the drum periphery past the print line 17. Afiixed to the periphery of the drum, the print type may be for the printing of digits 0 to 9 and any other desired ariihmetical signs. As illustrated, the printing type are arranged on the drum periphery in rows parallel to the drum axis and in columns which extend partway around the drum. The columns of printing type extend only partway around the drum because of the need for the allowance of sufficient time for the retraction operation of the hammer 14 as will be hereinafter more fully understood. Also, the printing type are arranged such that the characters of each column are in sequence and the characters of each row are repetitive. The term column is herein defined by the dot and dash lines shown on the drum periphery of FIG. 9, the columns being contiguous axially of the drum and of equal width; as shown. For purposes of description it may be assumed that the columns are each of .1 inch in width.

The carrier 16 comprises a body 24 which is slidably supported and guided on a pair of spaced apart parallel guide rods 25, securely mounted on the base 10, the rods being parallel with the print line 17. The hammer 14 is pivotally mounted on a post 26 on the carrier 16 and is biased to a retracted position by a spring 27 against an adjustable stop member 29. Also mounted on the carrier 16 there is an electrically operated actuator or armature of a solenoid 28 which when energized actuates the hammer 14.

In FIGS. 1 and 9 the carrier 16 is shown in its home position against an adjustable stop member 31 to which position the carrier is biased by a return spring 30. In the home position of the carrier 16, as shown in FIG. 9, the upper striker end 32 of the hammer is rightwardly of the first column of printing type on the drum 12 by a predetermined distance which may be equal to the width of a column on the drum or multiple thereof. In the present illustration, the predetermined distance from the first column of the drum 12 to the home position of the hammer is .2 inch. The hammer 14 is returned to the home position at the completion of a line of print, preparatory to the start of serially printing the next line.

In accordance with a feature of the invention, a connector or clutch device 34 is provided to operatively connect the carrier 16 to the motor 21 to effect lineal travel of the hammer 14 along the print line 17. The clutch device 34 comprises a continuously driven feed means, or clutch component or toothed belt 36 and a cooperable toothed clutch component 38. The clutch component 38 is carried by the carrier 16 and is biased to disengaged position by a compression spring 41, as shown in FIG. 5. The belt 36 is of the endless type and travels about a toothed driven pulley 41 and a guide pulley 42, spaced apart longitudinally of the print line 17. The

pulleys

41 and 42 are mounted on upright members of the base 10 with their axes of rotation horizontally disposed, the driven pulley 41 being atfixed to a driven shaft 44 which is connected by a worm gear and wheel connection 46 and belt 22 to the continuously rotating drum shaft 18.

The gear ratio is such as to synchronize the rotation of the drum 12 with the linear speed of travel of the hammer carrier 16 such that for each revolution of the drum the hammer will move a distance equal to the width of a column or .1 inch of the present illustration.

The clutch component 38 may be carried on the underside of a web 47 joining a pair of oppositely disposed legs 48 which slide vertically between a pair of

guide members

49 and 50, integral with the carrier 16. As shown in FIG. 2, the lower side of the belt 36 passes between the legs 48 with the belt teeth facing upwardly for engagement with similar teeth on the clutch component 38. Also carried by the carrier 16 there is an electrically operated actuator or core 51 of a solenoid 52 to move the clutch component 38 downwardly into engagement with the teeth of the belt. Integral with the body 24 there is a rearwardly disposed extension 52 which extends upwardly and then rearwardly to provide a horizontal mounting 53 for a pair of laterally spaced apart

ink ribbon reels

54 and 55.

A switch 60 is provided and mounted on the rightward side of the base 10, as seen in FIG. 1, and the purpose of the switch is to assure that the clutch solenoid 52 will not be energized unless the carrier 16 is in home position. The switch 60 comprises a pair of flexible thin metal contact members 62 and 64 arranged such that end portions thereof overlap each other, as shown in FIG. 8. The contact members 62 and 64 are made of a suitable magnetic or ferrous material and are spaced apart, as shown in FIG. 8, when not affected by a magnetic force. A permanent magnet 66 is positioned laterally of the contact members 62 and 64, overlying the overlapped end portions of the latter members, the magnet being spaced from the contact members a predetermined distance so as to provide for effective magnetic attraction for the contact members. A magnetic shunt member 68 has a normally retracted position, as shown in FIG. 4, and is movable to a position between the magnet 66 and the overlapped ends of the contact members 62 and 64 to divert the magnetic flux and thereby effect disengagement of the contact members. The shunt 68 is mounted on the end of a lever 70 which is pivoted to move the shunt out of the area of the magnetic field by and when the carrier 16 moves to its home position. As shown in FIG. 9, an end of an extension 71 of the carrier 16 engages an upstanding arm 72 of the lever 70 to pivot the lever clockwise whereby to move the shunt 68 out of the magnetic field as the carrier 16 moves to home position. A coil spring 73 functions to pivot the lever 70 counterclockwise as the carrier starts to move away from its home position and just prior to carrier movement of .2 inch, the shunt 68 is in position to effectively block the magnet 66 and cause contact 62 and 64 to open.

In alignment with and between the striking face of the hammer 14 and the print line 17 there is a hammer extension member or interposer 74. The interposer 74 is, in fact, the impression means of the printer and is car ried by the carrier 16 on the upper ends of two pair of resilient mounting members 76. These mounting members 76 are preferably spring wire members having their lower ends mounted on and secured to the carrier extension, mounting 53 on the other side of belt 36 from the ham mer 14.

Fixed onto the dmm shaft 18 to rotate therewith is a disc 77 of a pulse generator which includes a photoelectric cell 78 and a light source 80. The disc 77 is provided with a number of rectangular openings which are angularly spaced apart and are respectively representative of the rows of type on the drum 12. The cell 78 is positioned to respond to the light passing through the disc openings to generate electrical pulses in the well known manner and it will be understood that the openings in the disc are positioned with respect to the direction of rotation of the shaft 18, a predetermined distance in advance of the corresponding rows of type as shown in FIG. 3 for timing purposes in the operation of the hammer 14.

Referring more particularly to FIG. 9, the computer, designated generally by the reference character 84, is diagrammatically illustrated as including an information input source 86, a control unit or silicon control rectifier 88, a comparator 90, and an AND gate 92. The rectifier 88 is connected by a lead 94 to the clutch solenoid 52 and activation of the rectifier is under the mutual control of the computer input source and the switch 60. The switch 60 and the data source 86 have leads 104 and 98 respectively which connect to a gate 100 which in turn is connected to the rectifier 88. A control unit or electronic timer 101 which is a well known device in the art, functions to deactivate the rectifier 88 and, therefore, the solenoid 52, the timer being set to turn off the rectifier immediately upon completion of a line of printing. One terminal of the photoelectric cell 78 is connected by a lead 102 to the comparator which is connected by lead 108 to gate 92, and the switch contact 62 is connected by a lead 96 to the AND gate 92 so that the switch 60 and the cell 78 mutually control printing operation of the hammer 14. A lead 106 from the coil of the hammer solenoid 28 connects to a hammer power means which in turn is connected through gate 92 by a lead 108 to the comparator 90. The leg of the AND gate 92 to which the lead 96 is connected is the well known inverted or biased leg which is on when contacts 62, 64 are open.

OPERATION Assuming that the motor 21 is operating, and therefore is driving the drum 12 and the belt 36, a signal from the information input source 86 will be sent to the AND gate 100, and if the switch members 62, 64 are engaged, a signal therefrom to the AND gate will turn on the silicon control rectifier 88. When this occurs, the solea noid 52 will be energized to pull the clutch member 38. downwardly into coupling enggaement with the teeth of the belt 36. The carrier 16 will thus be coupled to the belt and carry the hammer 32, interposer 74 and ink ribbon along the print line. Upon move-ment of the car rier along the print line, the spring 73 begins to pivot the lever 70 counterclockwise and just before the hammer has traveled the illustrated distance of .2 inch, toward the first column of the drum type, the lever carried shunt 68 1S moved to its effective position in the field of the magnet 66 whereupon the switch contacts 62, 64 open. As a consequence, the inverted leg of the AND gate 92 is activated and also gate 100 is activated. At the same time the pulse generating cell 78 sends the pulses 0 to 9 to the comparator 90 where a match is found with the selected input character, the signal of which is sent to and AND gate 92 causing the hammer to operate. It will be understood that since the hammer travel is .1 inch for each revolution of the drum 12, the impression means 74 will be traveling across the column in position to strike the selected one of the type in column #1 and then in column #2, etc. To accomplish this, the width of the striker end of impression means 74 may be slightly wider than the width of a column of type but less than the distance from the center of one column to the next depending upon the speed of the drum. Upon reaching the end of the line of print, the control rectifier 88 is turned off by the computer deactivator 101 whereupon the clutch solenoid 52 is de-energized and allows the spring 27 to return the carrier to home position. When this occurs, the lever 70 is pivoted to withdraw the shunt whereup the switch contacts 62, 64 close as an indication that the impression means 76 is in home position and another line of printing can be initiated when a signal is received at the gate 100 from the information input source. It will be understood that the start signal from the computer may be at the gate 100 before the carrier reaches home position and that the next line of print will be started as soon as the switch contacts 62, 64 close.

What is claimed is:

1. In a high speed printer, a rotatable drum having type arranged in rows and columns in predetermined spaced apart relationship, said drum being driven continuously at a predetermined angular velocity to move the type past a print line, impression means mounted for movement along the print line from a home position and return, continuously driven means operable to move said impression means from home position along the print line, an electrically operated coupling member operable to couple said impression means to said continuously driven means, a magnetically operable switch means operatively connected to said electrically operable coupling member to control operation of the latter, a magnet spaced from said magnetically operable switch means to activate the later, and a shunt member positionable between said switch means and said magnet and retracted therefrom in response to return of said impression means to home position.

2. In a high speed printer as defined by claim 1 wherein said shunt member is biased to position between said magnet and said switch means and is held retracted from said position when said impression member is in home 3. In a high speed printer as defined by claim 1 Wherein said impression means is electrically operated and operatively connected to and controlled by said switch means.

4. In a high speed printer as defined by claim 1 with the inclusion of a carrier for said impression member operable to engage and retract said shunt member as said impression means approaches home position.

5. In a high speed printer as defined by claim 4 Wherein said shunt is carried by a lever pivoted by said carrier as said impression means approaches home position.

References Cited UNITED STATES PATENTS 2,843,243 7/1958 Masterson 101-93 3,039,708 6/ 1962 Chidgey et al 74-37 XR 3,135,195 6/1964 Potter 10l93 3,289,805 12/1966 Kleinschmidt et a1. 197-18 3,331,316 7/1967 Bretti 101-93 3,399,753 9/1968 Revelle 197-49 3,406,625 10/1968 Chamness et a1, 197-55 XR EDGAR S. BURR, Primary Examiner US. Cl. X.R.