GB2092071A

GB2092071A - Information printing methods and apparatus

Info

Publication number: GB2092071A
Application number: GB8139197A
Authority: GB
Original assignee: Bell and Howell Co
Current assignee: Bell and Howell Co
Priority date: 1981-02-02
Filing date: 1981-12-31
Publication date: 1982-08-11
Also published as: AU7775681A; GB2092071B; FR2511300A1; FR2511300B1

Abstract

A circular platen (21) has a first peripheral portion (22) and a second peripheral portion (24) having a radius (25) exceeding the radius (23). The platen (21) is mounted for rotation. A sheet entry gap (28) is provided between the platen (21) and the print head (15) by moving the first peripheral portion (22) into first proximity to the print head (15). A print gap relative to the print head (15) is provided by moving the second peripheral portion (24) of the platen (21) into second proximity to the print head (15). Since the first proximity is larger than the second, jamming of the entering sheet (19) at the print head (15) is effectively avoided. The smaller proximity readily permits realization of whatever small print gaps are typically required by dot-matrix print heads or other printing devices. <IMAGE>

Description

SPECIFICATION Information printing methods and apparatus This invention relates to a method and apparatus for printing information on a sheet of material, such as by means of a dot-matrix print head or other printing device.

A frequent requirement in the use of dotmatrix print heads and other printing devices is that a certain narrow gap be provided between the active portion of the print head or other printing device and the platen used to back up the paper or other sheet of material onto which information is printed. As the leadintg edge of the sheet enters such narrow gap, jams tend to occur, especially if the edge of the entering sheet is not perfectly flat.

In an effort to overcome this disadvantage, it has been proposed to position a flat platen at a wide gap from from the print head, and to enter the sheet into such wide gap. Either the head of the flat platen are then translatorily moved with an actuator so as to close the gap between the head and the platen down to a working distance, keeping the entered sheet at the requisite close range to the print head.

The mechanism required to accomplish the latter task tends to be complex and is prone to wear and misadjustment. Such problems generally are aggravated in the case of modern printing methods wherein the entering sheet is moved into position at the print head at a rate consistent with printing speed.

According to one aspect of the invention a method and apparatus for printing information on a sheet of material provide a circular platen with a first peripheral portion having a first radius and a second peripheral portion having a second radius exceeding the first radius.

Such circular platen is mounted for rotation about an axis adjacent a print head. A sheet entry gap is provided between the platen and the print head by moving the first peripheral portion about the mentioned axis into first proximity to the print head, and a sheet is entered into such entry gap between the platen and the print head. A print gap relative to the print head is provided by moving the second peripheral portion of the platen about the mentioned axis into second proximity to the print head, at the entered sheet. Since the mentioned first proximity is larger than the latter second proximity jamming of the entering sheet at the print had is effectively avoided.On the other hand, the resulting smaller proximity readily permits realization of whatever small print gaps are typically required by dot-matrix print heads or other printing devices which print the desired information on the sheet at the print gap.

The invention is illustrated by way of example in the accompanying drawings, in which like reference numerals designate like or functionally equivalent parts, and in which: Figure 1 is an elevation of a printing apparatus according to preferred embodiment of the subject invention; Figure 2 is a top view of the. printing apparatus of Fig. 1, with added paper drive; and Figure 3 is view similar to Fig. 2, showing the illustrated printing apparatus in an active printing position.

The printing apparatus 10 shown in the drawings has a baseplate 1 2 shown only in Fig. 1 and a paper drive 1 3 and 14 shown only in Fig. 2, to avoid unnecessary crowding of the remaining figures.

The apparatus 10 also has a print head 1 5 mounted on the baseplate 1 2. The print head 1 5 may be of the familiar dot-matrix type. As is well known, a dot-matrix print head has an array of rods or wires 1 6 which are selectively actuated by a corresponding array of magnetic actuators located in a housing 1 7. During operation, such actuators selectively thrust the wires 1 6 through the active front end 1 8 of the print head 15, against the paper 1 9 or other sheet of material onto which information is to be printed; with "information" being herein considered sufficiently broad to cover all kinds of intelligence, characters, and data.

As seen in the drawings, the subject invention provides a circular platen 21 with a first peripheral portion 22 having a first radius 23, and a second peripheral portion 24 having a second radius 25 exceeding the first radius 23. In the illustrated embodiment, the first and second peripheral portions 22 and 24 are of equal length. These peripheral portions 22 and 24 also may be of equal widths, though Fig. 1 shows a narrower width for the second peripheral portion 24, than for the first peripheral portion 22, as adapted to a configuration of the print head 1 5.

The circular platen 21 is mounted for rotation about an axis adjacent the print head 15, such as by means of a shaft 27.

A sheet entry gap 28 is provided between the platen 21 and the print head 15 or active front potion 1 8 thereof, by moving the first peripheral portion 22 about the axis of the shaft 27 into first proximity to the print head 1 5 or active front portion 18, as seen in Figs.

1 and 2. A platen drive 29 may be employed for this purpose and may be mounted on the baseplate 12, for rotation of the shaft 27 relative to such baseplate.

The sheet 1 9 is entered into the entry gap 28 between the platen 21 and the print head 1 5. To this end, the paper or sheet drive 1 3 and 14 may be employed. As seen in Fig. 2, the sheet drive may include oppositely rotating rollers which engage and advance the sheet 1 9 therebetween. In practice, these rollers may be rotated by conventional drive motors or means and may be supplemented or replaced by other conventional paper trans port conveyors.

A frame 31 may be employed for guiding the sheet 1 9 into and through the entry gap 28 and thereby to and past the print head 1 5 and platen 21.

If desired, both the sheet 1 9 and the platen 21 may be moved simultaneously into position at the print head 1 5. Also, the sheet 1 9 may be moved into position relative to the print head 1 5 at a rate consistent with the particular printing speed.

According to the subject invention, the illustrated preferred embodiment then provides a print gap 33 relative to the print head 1 5 or active front portion 18 at the entered sheet 19, by moving the second peripheral portion 24 about the axis of the shaft 27 into second proximity to the print head 15, smaller than the first proximity mentioned above in connection with the sheet entry gap 28. In practice, this may accomplished by rotating the circular platen 21 with the drive 19 through an angle of 180 .

In this manner, a narrow print gap 33 as requisite for a proper printing operation by the head 1 5 is established, even though the gap 28 at the head 1 5 initially was wide enough to prevent jamming of the sheet 1 9 at the print head.

As already indicated to some extent, the platen 21 may be selectively rotated about its axis of rotation, such as by the drive 29, to provide first the wider entry gap 28 and then the narrower print gap 33. The entered sheet 1 9 may be moved along with the rotating platen 21 during printing of the information with the print head 1 5. The shaft 27 and drive 29 are thereby coupled to the circular platen 21 for selectively rotating such platen about its axis of rotation.

The second peripheral 24 of the circular platen 21 may be rendered susceptible to inking, such as by roughing such surface with a wire brush or other tool. A portion of such roughened, ink susceptible surface is seen at 35 in Fig. 1.

The susceptible second peripheral portion 24 is inked, such as by means of an ink roller 36 which is rotatably mounted on the baseplate 1 2 by a bearing 37 and shaft 38.

The roller 36 may be of conventional type, including an ink-bearing body of absorbent material. If desired, the ink roller 36 may be mounted on a spring-biased lever, which urges the circumference of the ink roller 36 into intimate contact with the ink-retaining surface 35 of the rotating platen.

Because of the relative width of the entry gap 28, an undesired inking of the sheet 1 9 from the ink surface 35 is effectively avoided.

The desired information is printed with the print head 1 5 onto the sheet 1 9 at the established narrow print gap 33 as seen in Fig. 3. In terms of the illustrated preferred embodiment, ink may be transferred from the inked second peripheral portion 24 to the sheet 1 9 at the print gap 33 with the print head 15, in order to print the desired information on the side of the sheet 1 9 facing the platen 21. The print head wires 16 may be selectively thrust against the sheet 1 9 for a selective ink transfer from the second peripheral portion 24 to the sheet 1 9.

If desired, the circular platen 21 may be rotated and the entered sheet 1 9 may be moved with the inked second peripheral portion 24 during the transfer of ink therefrom.

In practice, means other than the illustrated dot-matrix print head 1 5 may be employed for printing information on the sheet 1 9 at the narrower print gap 33. The circular platen may thus be mounted for rotation about the mentioned axis adjacent to an object providing the sheet entry gap 28 relative to the platen 21 upon rotation of the first peripheral portion 21 about the mentioned axis into first proximity to such object. The sheet is then entered into the entry gap 28 between the platen 21 and the latter object.A print gap 33 is then provided between the mentioned object and the platen 21 at the entered sheet 1 9 by moving the second peripheral portion 24 about its axis into second proximity to the mentioned object, with such second proximity being again smaller than the first proximity at the sheet entry gap 28.

In the terms of structure, there thus is a print head 1 5 or other means adjacent the mounted platen 21 for providing a sheet entry gap 28 at the first peripheral portion 22, and for providing a print gap 33 at the second peripheral portion 24 upon movement of such second peripheral portion about the axis of rotation of the platen 21 to the print head 1 5 or other gap providing means.

In either case, information is printed onto the sheet 1 9 at the narrower print gap 33.

The first and second peripheral portions 22 and 24 are concentric relative to the axis of rotation of the platen 21. However, if the unequal radii 23 and 25 are aligned as a diameter through the axis of rotation of the platen 21, then it may be seen that such axis of rotation or center of the platen 21 is in effect eccentric relative to the combined circumference 22 and 24 of the platen 21. In principle, the requisite peripheral portions of the platen 21 for realizing sequentially the wide sheet entry gap 28 and the narrow print gap 33 may thus be realized by an eccentric location of the axis of rotation along which the drive shaft 27 extends.

Upon completion of a printing operation as seen in Fig. 3, the platen 21 may be rotated by the drive 29 in order to restore the wider sheet entry gap 28 as seen in Figs. 1 and 2.

This may be accomplished by moving the first peripheral portion 22 from the position shown in Fig. 3 about the axis of rotation of the platen 21 back into the position shown in Figs. 1 and 2.

A prototype of the subject invention has been successfully tested in a remittance processing terminal, for printing information and data on moving checks and other payment documents. Also, specific use of the subject invention was made in an endorser mechanism for printing an imprint of a rubber die in conjunction with a date by means of a mechanism of disclosed type, employing a platen 21.

Claims

1. A method of printing information from a print head on a sheet of material, comprising in combination the steps of: providing a circular platen with a first peripheral portion having a first radius and a second peripheral portion having a second radius exceeding said first radius; mounting said circular platen for rotation about an axis adjacent said print head; providing a sheet entry gap between said platen and said print head by moving said first peripheral portion about said axis into first proximity to said print head; entering said sheet in said entry gap between said platen and said print head;; providing a print gap relative to said print head by moving said second peripheral portion about said axis into second proximity to said print head at said entered sheet, said second proximity being smaller than said first proximity and printing said information with said print head onto said sheet at said print gap.

2. A method as claimed in claim 1, including the step of; selectively rotating said circular platen about said axis to provide first said entry gap and then said print gap.

3. A method as claimed in claim 1 or 2, including the steps of: rotating said circular platen and moving said entered sheet along with said rotating platen during printing of said information with said print head.

4. A method as claimed in claim 1 or 2, including the steps of: rendering said second peripheral portion susceptible to inking; inking said susceptible second peripheral portion; and transferring ink from said inked second peripheral portion to said sheet at said print gap with said print head.

5. A method as claimed in claim 4, including the step of: rotating said circular platen and moving said entered sheet along with said inked second peripheral portion during said transferring of ink.

6. A method of printing information on a sheet material, comprising in combination the steps of: providing a circular platen with a first peripheral portion having a first radius and a second peripheral portion having a second radius exceeding said first radius; mounting said circular platen for rotation about an axis adjacent to an object; providing a sheet entry gap relative to said platen upon rotation of said first peripheral portion about said axis into first proximity to said object; entering said sheet in said entry gap between said platen and said object; providing a print gap between said object and said platen and said entered sheet by moving said second peripheral portion about said axis into second proximity to said object, smaller than said first proximtiy; and printing said information onto said sheet at said point gap.

7. A method as claimed in claim 6, including the step of: selectively rotating said circular platen about said axis to provide first said entry gap and then said print gap.

8. A method as claimed in claim 6 or 7, including the steps of: rotating said circular platen and moving said centered sheet along with said rotating platen during printing of said information on said sheet.

9. A method as claimed in claim 6 or 7, including the steps of: rendering said second peripheral portion susceptible to inking; inking said susceptible second peripheral portion; and selectively transferring ink from said inked second peripheral portion to said sheet at said print gap to print said information on said sheet.

10. A method as claimed in claim 9, including the step of: rotating said circular platen and moving said entered sheet along with said inked second peripheral portion during said transferring of ink.

11. A apparatus for printing information from a print head on a sheet of material, comprising in combination: a circular platen including a first peripheral portion having a first radius and a second peripheral portion having a second radius exceeding said first radius; means for mounting said circular platen for rotation about an axis adjacent said print head; means for providing a sheet entry gap between said platen and said print head by moving said first peripheral portion about said axis into first proximity to said print head; means for entering said sheet in said entry gap between said platen and said print head means for providing a print gap relative to said print head at said entered sheet by moving said second peripheral portion about said axis into second proximity to said print head, smaller than said first proximity; and means connected to said print head for causing said print head to print said information onto said sheet at said print gap.

1 2. Apparatus as claimed in claim 11, wherein: said sheet entry gap providing means and said print gap providing means jointly include means coupled to said circular platen for selectively rotating said platen about said axis.

1 3. Apparatus as claimed in claim 11, including: means coupled to said circular platen for rotating said platen; and means for moving said entered sheet along with said rotating platen during printing of said information with said print head.

14. Apparatus as claimed in claim 11, 1 2 or 13, wherein: said second peripheral portion has a surface susceptible to inking; said apparatus includes means for inking said susceptible surface; and said means connected to said print head include means for selectively transferring ink from said inked surface to said sheet.

1 5. Apparatus for printing information on a sheet of material, comprising in combination: a circular platen including a first peripheral portion having a first radius and a second peripheral portion having a second radius exceeding said first radius; means for mounting said circular platen for rotation about an axis; means adjacent said mounted platen for providing a sheet entry gap at said first peripheral portion, and for providing a print gap at said second peripheral portion upon movement of said second peripheral portion about said axis to said gap providing means; means for entering said sheet in said entry gap; and means for printing said information onto said sheet at said print gap.

16. Apparatus as claimed in claim 15, wherein: said sheet entry gap providing and print gap providing means include means coupled to said circular platen for selectively rotating said platen about said axis.

1 7. Apparatus as claimed in claim 15, including: means coupled to said circular platen for rotating said platen; and means for moving said entered sheet along with said rotating platen during printing of said information.

1 8. Apparatus as claimed in claim 15, 1 6 or 17, wherein: said second peripheral portion has a surface susceptible to inking; said apparatus include means for inking said susceptible surface; and said printing means include means for selectively transferring ink from said inked surface to said sheet.

1 9. A method of printing information from a print head on a sheet of material substantially as herein before described with reference to and as illustrated in the figures of the accompanying drawing.

20. A method of printing information on a sheet of material substantially as hereinbefore described with reference to and as illustrated in the figures of the accompanying drawing.

21. An apparatus for printing information from a print head on a sheet of material substantially as hereinbefore described with reference to and as illustrated in the figures of the accompanying drawing.

22. An apparatus for printing information on a sheet of material substantially as hereinbefore described with reference to and as illustrated in the figures of the accompanying drawing.

23. The features as herein disclosed, or their equivalents, in any novel selection.