GB1571163A

GB1571163A - Print element cartidge and printer

Info

Publication number: GB1571163A
Application number: GB5143577A
Authority: GB
Original assignee: International Business Machines Corp
Current assignee: International Business Machines Corp
Priority date: 1976-12-27
Filing date: 1977-12-09
Publication date: 1980-07-09
Also published as: IT1118055B; FR2375047B1; DE2755090A1; FR2375047A1; JPS5383826A

Description

(54) PRINT ELEMENT CARTRIDGE AND PRINTER (71) We, INTERNATIONAL BUSI NESS MACHINES CORPORATION, a Corporation organized and existing under the laws of the State of New York in the United States of America, of Armonk, New York 10504, United States of America do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to print element cartridges for printer and printers incorporating such cartridges.

There are many different types of printer available, of which some, such as the golf ball and daisy wheel printers, may be termed single element printers in that the types are carried on a single assembly and move with it in relation to the medium upon which printing is to be effected. The physical size of the assembly is small in relation to the length of the length of the print line.

Typebar printers are not single element printers because each type carrying bar is actuable independently. Sliding bar printers are not single element printers because the length of the bar is at least as long as the length of the print line. Chain and belt printers having a span of the chain or belt facing the print line are not single element printers when the chain or belt span is approximately the length of the print line.

It has been proposed to provide a printer having an endless character belt and hammer assembly mounted on a carrier movable along a print line. The span of the belt facing the print line is less than the length of the print line. The carrier includes means to rotate the belt to present each of a set of characters in turn between the hammer assembly and a platen. Such a printer is hereinafter referred to as a single element.

character belt printer. By the invention, a character belt is enclosed in a cartridge to form a compact print element which can be readily installed and removed.

According to the invention, a print element cartridge for a single element character belt printer comprises a housing including means to releasably mount the housing on the carrier of the printer, an aperture to receive the hammer assembly of the printer, an endless type character belt rotatably mounted in the housing to present a span which, in the mounted position on the carrier, is exposed between the hammer assembly and platen of the printer, and means to connect the belt mounting to the belt rotation means on the carrier of the printer.

A single element character belt printer, according to the invention, includes means to releasably mount such a cartridge on the carrier, the hammer assembly projecting through the housing aperture in the mounted position of the cartridge, and the belt rotation means being connected to the belt mounting in the mounted position of the cartridge.

The scope of the invention is defined by the appended claims; and how it can be carried into effect is hereinafter particularly described with reference to the accompanying drawings, in which: FIGURE 1 is a perspective view of a single element character belt printer according to the invention with a print element cartridge mounted on the printer carrier; FIGURE 2 is a bottom perspective view of the cartridge housing without its contents; FIGURE 3 is a top perspective view of the cartridge; FIGURE 4 is an exploded perspective view of the cartridge and part of the carrier structure:: FIGURE 5 is a side view of the cartridge during mounting on the carrier; FIGURE 6 is a diagrammatic plan view, partly sectioned, of the cartridge with the hammer assembly carried by the carrier; FIGURE 7 is similar to Figure 6 with the various components in the position occupied during printing; FIGURE 8 is a view, partly in section, of part of the character belt and the hammer mechanism.

FIGURE 9 is a perspective view partly broken away of switching mechanism on the carrier for cooperating with the cartridge; and FIGURE 10 is a side view of portions of the switching mechanism of Figure 9.

A printer 1 (Fig. 1) has a keyboard 2, a rotatable lead-screw 3, a print element carrier 4, a print element cartridge 5, and a rotatable platen 6. Rotation of the leadscrew 3 causes movement of the carrier 4 along a print line across the platen 6. The print element cartridge 5 is removably mounted on the carrier 4.

The cartridge 5 (Fig. 2) has a bottom 6 with an elongated opening 8 and a circular opening 81. The opening 8 (Fig. 4) accommodates a print hammer mechanism comprising a hammer 14 and a character plunger 15.

The cartridge 5 carried by the carrier 4. The back of the cartridge 5 (Fig. 4) has a combination of grooves and ribs 22, 23 and 24, which cooperate with individual switches of a switching mechanism carried by the carrier.

The switches have keybuttons 49, 50 and 51 (Fig. 1). Actuation of the switches serves to condition the printer 1 in terms of appropriate print intensity, pitch and base index (line spacing), for proper printing operation with a chosen cartridge. Thus individual cartridges will have grooves or ribs at the appropriate location in accordance with the requirements of their contents and may have more or less than three locations for grooves or ribs according to the number of switches and functions to be controlled.

The carrier 4 has a motor 19 with a shaft 20 and bevelled drive gear 21. The shaft 20 extends through a base plate 18 which is carried by the carrier 4. When a cartridge 5 is installed on carrier 4, the shaft 18 projects through the opening 81 so that the gear 21 is within the cartridge. The motor 19 may be a stepper motor, having appropriate controls for driving and positioning the gear 21.

Moulded into the sides of cartridge 5 are recesses 12 and 13 which co-operate with tabs 16 and 17 integral with the base plate 18, enabling a snap connection and removal of the cartridge 5 (Fig. 5) onto the base plate 18 on the carrier 4.

A double loop endless character band 9 (Fig. 6) passes around rollers 31 and 32, drive wheel 36 rollers 37 and 38 (Fig. 7) and roller 35 in the cartridge 5. The gear 21 engages complementary formations (not shown) on the bottom of the drive wheel 36 with the cartridge in position. Rollers 31 and 32 are carried by an expandable yoke made up of arms 29 and 27, having a common pivot in the cartridge 5 and biased apart by springs 28 and 30. The band 9 is tensioned by springs 28 and 30 and in its normal position (when printing is not taking place) is exposed but within the limits of the cartridge 5 (Fig. 3).

Arms 27 and 29 have inward facing protuberances with bevelled surfaces 34 and 33, which engage co-operating bevelled surfaces 40 and 41 (Fig. 7) on a wedge 26 integral with the plunger 15. A spring 25 acts on the plunger 15 and engages a stop (not shown) to provide a return action.

The rollers 37 and 38 are rotatably mounted at the ends of arms having a common pivot in the cartridge, spring biased apart and forming an expandable yoke similar to the arms 27 and 29. The roller 35 is rotatably mounted in the cartridge 5 as is the drive wheel 36. The character band 9 thus presents two spans, an upper one and lower one 10, and carries a plurality of character slugs 42, of which one only is shown in Figs. 6 and 7.

The character band 9 is flexible material, such as a polymeric material or thin steel.

The character slug 42 (Fig. 8) is made up of a type 43 on one side of the band and a lug 44 on the other side. The lug 44 has an integral cone 45 and the plunger 15 has a complementary recess 46 in its adjacent end. The cones 45 engage in similar recesses (not shown) in the drive wheel 36, and rollers 31, 32, 35, 37 and 38.

The printer 1 has a control system which, upon selection of a character to be printed by depression of a key on the keyboard 2, energises themotorl9to rotate the shaft20and gear 21. The latter rotates the drive wheel 36 and thus the character band 9 until the correct slug 42 is aligned with the plunger 15. The control system also calculates whether the correct slug 42 will first arrive on the upper span or the lower span 10 of the band 9. If the latter, then the base plate 18, which is pivoted on the carrier, is tilted to present the lower span 10 to the plunger 15. Otherwise, the cartridge 5 remains with the upper span level with the plunger 15.

For printing upon a sheet 39 against the platen 6, an ink ribbon is located with a span between the cartridge 5 and the sheet 39. The ribbon may extend across the print line on the platen or be carried by the carrier 4.

When the correct slug 42 is aligned with the plunger 15, the hammer 14 is fired by the control system and drives the plunger 15 towards the platen 6. The recess 46 in the end of the plunger 15 (Fig. 8) engages the cone 45 on the lug 44 of the correct slug 42 so as to centre the type 43 with the print position.

The plunger 15 continues its movement towards the platen 6, bending the upper span of the band 9 (Fig. 7). The band 9 is relatively inextensible and draws the rollers 31 and 32 together. The arms 27 and 29 are pivoted against the springs 28 and 30, the wedge 26 having been moved away from the surfaces 33 and 34. During this time, the lower span 10 of the character band remains in its normal position.

Just prior to printing of a character on the sheet 39, the hammer 14 is restored to the normal position (Fig. 7). Following printing, the plunger 15 is restored in a very short time to the normal position (Fig. 6) by the character band 9 which transmits the force of springs 28 and 30 and by the spring 25.

Dampmg is provided for the plunger 15 by the wedge 26 coming back into contact with the surfaces 33 and 34 on the arms 27 and 29.

The base plate 18 need not be pivoted on the carrier 4 if an increased selection time is acceptable. In such case, the plunger 15 is always aligned with the upper or lower span of the character band 9, as the case may be, and the control system waits until the correct slug is aligned with the plunger 15 on the upper or lower span, as the case may be.

Alternatively, a single loop character band may be used, passed around a pair of rollers and a drive wheel.

With a pivoted base plate, two single loop character bands may be used, carrying, for example, upper and lower case character slugs. In this case, the bands would pass around individual pairs of rollers and commonly driven drive wheels or a common drive wheel.

The switching mechanism (Figs. 9 and 10) includes a frame 52 in which three plungers are slidable, of which two only 64 and 65 are shown. The plungers 64 and 65 have extensions 73 and 74, to pass through groove 24 or to be engaged by rib 23. The plungers 64 and 65 have lower legs 62 and 63 guided in openings 58 and 59 in the frame 52 and upper legs 71 and 72 also guided in openings in the frame and carrying the keybuttons 51 and 50.

Springs 60 and 61 surround the legs 62 and 63 and urge the plungers 64 and 65 upwardly.

The plungers 64 and 65 have slots 67 and 69 through which extends a slider 53 guided by the frame 52 and spring biased by a spring 70.

The slider 53 has recesses 54 and 56 in its upper surface and fingers 55 and 57 extend into these recesses. In the raised position of the plunger 64 (Fig. 9), the finger 55 extends through the slot 67. The plungers have apertures 66 and 68 above the slots 67 and 69. In the depressed position of the plunger 65 (Fig. 9), the finger 57 extends through the aperture 68. The fingers 55 and 57 are shaped to cam the slider 53 against the spring 70 during movement of the plungers.

The plungers carry individual switch contacts whose operation conditions the printer control system for a particular function related to the particular cartridge inserted. Thus, the plunger 65 (Fig. 10) carried connected contacts 75 and 77 electrically insulated from the plunger. These constitute the movable contacts of a switch whose fixed contacts 76 and 78 are engaged by the movable contacts upon depression of the plunger and are electrically connected to the control system.

The positions of the keybuttons serves to provide the operator with a visual indication of the pitch, print intensity and base index selected. The keybuttons can be used manually to select pitch, print intensity and base index if the cartridge does not have any ribs and grooves or to override the automatic selection by cartridge insertion. The switching mechanism can have as many plungers similar to plunger 65 as there are ribs or grooves on cartridge 5.

The switching mechanism remains in its set position, whether set by cartridge insertion or manually, until further setting by cartridge insertion or manually when there is automatic reset before further setting.

For example, if the plunger 64 is depressed upon installation of a different cartridge, when only the plunger 65 is depressed, or if the keybutton 51 is depressed in these conditions, the plunger 65 with the keybutton 50 will automatically restore. As the plunger 64 is lowered, the rib between the slot 67 and the aperture 66 engages the finger 55 and cams the slider 53 against the spring 70.

This removes the finger 57 from the aperture 57 in the plunger 65, allowing the plunger 65 to be moved up by the spring 61. During further downward movement of the plunger 64, the finger 55 enters the aperture 66 and latches the plunger 64 in its lower position.

Interchangeable character band cartridges may thus be provided for a single printer.

Each cartridge may carry coded formations, in accordance with the particular character set on the band or bands in the cartridge, to co-operate with switch mechanism on the carrier.

It will be understood that the expandable biased yokes may be eliminated and the rollers carried thereon be rotatably mounted on fixed axes in the housing, if the inner roller is rotatably mounted in a manner permitting movement towards the hammer assembly against a spring bias.

WHAT WE CLAIM IS: 1. A print element cartridge for a single element character belt printer, as hereinbefore defined, comprising a housing including means to releasably mount the housing on the carrier of the printer, an aperture to receive the hammer assembly of the printer, an endless type character belt rotatably mounted in the housing to present a span which, in the mounted position on the carrier, is exposed between the hammer assembly and platen of the printer, and means to connect the belt mounting to the belt rotation means on the carrier of the printer.

2. A cartridge according to claim 1, in which the character belt is entrained around rollers, at least one of whioh is biased to tension the belt.

3. A cartridge according to claim 2, in

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. sheet 39, the hammer 14 is restored to the normal position (Fig. 7). Following printing, the plunger 15 is restored in a very short time to the normal position (Fig. 6) by the character band 9 which transmits the force of springs 28 and 30 and by the spring 25. Dampmg is provided for the plunger 15 by the wedge 26 coming back into contact with the surfaces 33 and 34 on the arms 27 and 29. The base plate 18 need not be pivoted on the carrier 4 if an increased selection time is acceptable. In such case, the plunger 15 is always aligned with the upper or lower span of the character band 9, as the case may be, and the control system waits until the correct slug is aligned with the plunger 15 on the upper or lower span, as the case may be. Alternatively, a single loop character band may be used, passed around a pair of rollers and a drive wheel. With a pivoted base plate, two single loop character bands may be used, carrying, for example, upper and lower case character slugs. In this case, the bands would pass around individual pairs of rollers and commonly driven drive wheels or a common drive wheel. The switching mechanism (Figs. 9 and 10) includes a frame 52 in which three plungers are slidable, of which two only 64 and 65 are shown. The plungers 64 and 65 have extensions 73 and 74, to pass through groove 24 or to be engaged by rib 23. The plungers 64 and 65 have lower legs 62 and 63 guided in openings 58 and 59 in the frame 52 and upper legs 71 and 72 also guided in openings in the frame and carrying the keybuttons 51 and 50. Springs 60 and 61 surround the legs 62 and 63 and urge the plungers 64 and 65 upwardly. The plungers 64 and 65 have slots 67 and 69 through which extends a slider 53 guided by the frame 52 and spring biased by a spring 70. The slider 53 has recesses 54 and 56 in its upper surface and fingers 55 and 57 extend into these recesses. In the raised position of the plunger 64 (Fig. 9), the finger 55 extends through the slot 67. The plungers have apertures 66 and 68 above the slots 67 and 69. In the depressed position of the plunger 65 (Fig. 9), the finger 57 extends through the aperture 68. The fingers 55 and 57 are shaped to cam the slider 53 against the spring 70 during movement of the plungers. The plungers carry individual switch contacts whose operation conditions the printer control system for a particular function related to the particular cartridge inserted. Thus, the plunger 65 (Fig. 10) carried connected contacts 75 and 77 electrically insulated from the plunger. These constitute the movable contacts of a switch whose fixed contacts 76 and 78 are engaged by the movable contacts upon depression of the plunger and are electrically connected to the control system. The positions of the keybuttons serves to provide the operator with a visual indication of the pitch, print intensity and base index selected. The keybuttons can be used manually to select pitch, print intensity and base index if the cartridge does not have any ribs and grooves or to override the automatic selection by cartridge insertion. The switching mechanism can have as many plungers similar to plunger 65 as there are ribs or grooves on cartridge 5. The switching mechanism remains in its set position, whether set by cartridge insertion or manually, until further setting by cartridge insertion or manually when there is automatic reset before further setting. For example, if the plunger 64 is depressed upon installation of a different cartridge, when only the plunger 65 is depressed, or if the keybutton 51 is depressed in these conditions, the plunger 65 with the keybutton 50 will automatically restore. As the plunger 64 is lowered, the rib between the slot 67 and the aperture 66 engages the finger 55 and cams the slider 53 against the spring 70. This removes the finger 57 from the aperture 57 in the plunger 65, allowing the plunger 65 to be moved up by the spring 61. During further downward movement of the plunger 64, the finger 55 enters the aperture 66 and latches the plunger 64 in its lower position. Interchangeable character band cartridges may thus be provided for a single printer. Each cartridge may carry coded formations, in accordance with the particular character set on the band or bands in the cartridge, to co-operate with switch mechanism on the carrier. It will be understood that the expandable biased yokes may be eliminated and the rollers carried thereon be rotatably mounted on fixed axes in the housing, if the inner roller is rotatably mounted in a manner permitting movement towards the hammer assembly against a spring bias. WHAT WE CLAIM IS:

1. A print element cartridge for a single element character belt printer, as hereinbefore defined, comprising a housing including means to releasably mount the housing on the carrier of the printer, an aperture to receive the hammer assembly of the printer, an endless type character belt rotatably mounted in the housing to present a span which, in the mounted position on the carrier, is exposed between the hammer assembly and platen of the printer, and means to connect the belt mounting to the belt rotation means on the carrier of the printer.

3. A cartridge according to claim 2, in

which each of two rollers at the ends of the exposed span of the belt is rotatably mounted on a pivoted spring-biased arm.

4. A cartridge according to claim 3, in which the arms have a common pivotal axis to form an expandable yoke.

5. A cartridge according to claim 4, in which the yoke has formations engageable by the hammer assembly in the mounted position of the cartridge to locate the arms relative thereto.

6. A cartridge according to any preceding claim, including means on the housing to cooperate with switch mechanism on the carrier of the printer.

7. A cartridge according to claim 6, in which the co-operating means on the housing is a combination of ribs or grooves coded in accordance with the particular character belt in the cartridge.

8. A cartridge according to any preceding claim, in which the character belt is arranged as a double loop entrained around rollers and a drive wheel which includes the means to connect to the belt rotation means on the carrier of the printer.

9. A cartridge according to claim 8, in which the cartridge housing has an aperture through which the belt rotation means on the carrier of the printer projects, in the mounted position of the cartridge, to connect with the drive wheel.

10. A cartridge according to claim 8 or 9, in which, in the mounted position of the cartridge, two spans of the belt are exposed between the hammer assembly and platen of the printer.

1 t. A print element cartridge for a single element character belt printer, substantially as hereinbefore particularly described with reference to the accompanying drawings.

12. A single element character belt printer, as hereinbefore defined, including means to releasably mount a cartridge according to any preceding claim, the hammer assembly projecting through the housing aperture in the mounted position of the cartridge, and the belt rotation means being connected to the belt mounting in the mounted position of the cartridge.

13. A printer according to claim 12, in which the carrier includes a holder for the cartridge pivotable about an axis parallel to the exposed span of the belt in the mounted position of the cartridge.

14. A printer according to claim 12 or 13 in which the hammer assembly includes means to co-operate upon impact with means on the belt for positioning the belt to accurately locate a character type for printing.

15. A printer according to claim 14, in which the co-operating means comprise conical extensions on the belt and a conical recess in the hammer assembly.

16. A single element character belt printer with an interchangable print element cartridge, substantially as hereinbefore particularly described with reference to the accompanying drawings.