CA1056752A - Printing apparatus having improved spacing means - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A printing apparatus and a means for properly spacing adjacent characters printed by such apparatus wherein said apparatus includes a printing station, an image carrier, a color carrier, means for trans-ferring an image from the color carrier to the image carrier and means for advancing the color and image carrier into printing alignment and wherein said means for properly spacing adjacent characters includes a transparent font element having a raised character and visually detectable indicia for visually aligning the raised character relative to a previously printed, adjacent character.

Description

~0567~iZ

DRY PROCESS, LARGE LETTER PRINTING APPARATUS
BACKGROUND OF THE IN~'ENTION
The present invention relates generally to the field of lettering and printing equipment and, more specifically, to a printing apparatus having improved means for appropriately spacing and aligning the characters to be printed.
Although the advantages of the present invention can be realized in the printing of characters of any size, the present invention has particular application to the printing of relatively large characters.
Large characters of a size with which the present invention can be par-ticularly utilized are used for engineering drawing title blocks, slip charts, overhead transparencies, posters, silk screen stencils, signs, newspaper headlines, etc. These letters are generally larger than most typewriters or other impact printing devices can generate. In the past, three major methods have been used to generate letters or characters of this size: stencils, press-on letters and photo typesetters. Large lettering can also be done by freehand or by hand with the use of mechanical lettering aids.
The various lettering methods currently available all have certain drawbacks. To produce lettering of uniformly high quality by freehand or mechanical aid methods requires the skill of a trained draftsman, and involves considerable expense of time and money. Similarly, stencils and press-on letters take a relatively long time to form into words and sentences. In addition, it is easy to misalign letters and to get uneven spacing. Photo typesetting systems are rather large, permanent installations, having several chemical baths that must be maintained. A trained operator is necessary to get good results. In addition, generally the largest letter that can be produced without optics is the size of 35 mm film. The optics necessary to produce large letters increases the cost of the system significantly.
One of the critical variables in large character lettering is the 3o 1056~5Z

1 amount of blank or "white" space appearing between adjacent characters.
When printing relatively small characters, the spacing is not as critical since the amount of blank space between adjacent characters is not as readily detectible, In fact visually acceptable printing of relatively small charactérs can be accomplished by maintaining a constant space between adjacent characters, as in a typewriter. When printing relatively large characters, however, misaligned or improperly spaced characters are much more noticeable. If constant spacing is maintained between these larger characters, generally unacceptable character spacing results.
Therefore, one of the features which a large character printing apparatus must have in order to be acceptable is a means for maintaining proper spacing between adjacent characters. This generally involves attempting to maintain a constant amount of blank or "white" space between adjacent characters.
Such spacing cannot be done effectively by pure mechanical means since the amount of blank space between two adjacent characters is a function of the shapes of such characters.
SUMMARY OF THE INVFNTION
In general, the apparatus of the present invention provides means for maintaining a relatively constant amount of blank space between adjacent characters. Specifically, the printing apparatus allows the oper-ator to visually examine the contours of the adjacent, previously printed character and provides means by which the operator can insure that the printed characters will be spaced in a visually acceptable manner. In the present embodiment, such means includes a transparent font element having a series of indicia thereon, which indicia enable the operator to maintain a relatively constant amount of blank space between adjacent characters.
Structurally, the apparatus of the present invention comprises a printing station, an image carrier, a color carrier, and a transparent font element having a raised character thereon. The font element is postionable in printing registration with the printing station and includes visually detectable indicia for visually aligning the raised character relative to the character previously printed. The printing apparatus 1 further comprises means for guiding the image carrier and the color carrier into printing alignment with the printing station, means for transferring the image of the raised character on the font element from the color carrier to the image carrier, and means for advancing the image carrier and the color carrier relative to the printing station.
Accordingly, it is an object of the present invention to provide a printing apparatus having means for properly spacing adjacent characters by maintaining a relatively constant amount of blank space between sucl characters.
Another object of the present invention is to provide a means useable in a printing apparatus for maintaining proper spacing between relatively large characters.
A further object of the present invention is to provide means useable in a printing apparatus wherein such means includes a font element having indicia enabling the operator to maintain a relatively constant amount of blank space between adjacent characters.
These and other objects of the present invention will become apparent with reference to the drawings, the description of the preferred embodiment and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of the basic mechanism of the printing apparatus shown in its idle position with certain parts cut away.
Figure 2 is a perspective view of the basic mechanism of the printing apparatus in the print portion of its cycle with certain parts cut away.
Figure 3 is a plan view of the font element, the color carrier, and the image carrier.
Figure 4 is a side view of the font element.
Figures 5a-Sd show portions of several font elements with differ-ent letters, demonstrating the variety of indicia used for letters with different contours.
Figure 6 is a perspective view of a full set of font elements 1~5675Z

1 for use with the printing apparatus of the present invention.
Figure 7 is plan view of the printing station portion of the present invention showing the relationship between the piston head, tape and ribbon, font and font retainer.
Figure 8 is plan view as viewed along the line 8-8 of Figure 7 showing the means for guiding the tape and ribbon in a lateral direction.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Reference is first made to Figures 1 and 2 which illustrate the printing apparatus 10 of the present invention in various stages of opera-tion. It should be noted that each of these figures shows only the basic functional elements of the printing apparatus 10 and that in normal, commer-cial construction such apparatus and the components thereof would be sup-ported within a suitable housing (not shown).
In general, the apparatus 10 includes a main frame housing a printing piston assembly 47 which is moveable into printing engagement at a printing station 22 with a lettering font 20 and color and image carriers 32 and 34, respectively. The apparatus 10 further includes a font retainer 56 moveable into position directly above the piston assembly 47 and the letter-ing font 20 to resist the force created by movement of the piston assembly 47 during the printing cycle.
More specifically, the apparatus 10 includes a rigid frame which comprises a first pair of spaced-apart, generally parallel frame members 11 and 12 and a second pair of frame members 14 (only one of which can be seen in Figures 1 and 2) extending between the frame members 11 and 12 at gen-erally right angles and serving to integrally connect the elements 11 and 12 and maintain such elements in proper spaced relationship. The frame also includes a pair of upper frame elements 15 and 16 which are spaced from each other and which are horizontally disposed above the elements 11 and 12 in a generally perpendicular relationship. Similar to the frame member 14, the frame elements 15 and 16 serve to integrally connect the elements 11 and 12 and to maintain the entire frame assembly in a rigid construction.
As illustrated, the upper portion of each of the frame members 105675Z, l 11 and 12 includes a recessed or cut-away portion 24 near its center which, as will be hereinafter discussed, provides support for the printing ele-ments and defines, in part, the printing station 22. The upper frame ele-ments 15 and 16 are spaced from each other and include portions extending over the recessed area 24 of the frame elements 11 and 12 forming a pair of rails 58 and 60 or guiding means for guiding movement of the font retainer 56. The rails 58 and 60 are parallel to each other and extend perpendicular to the travel of the color and image carriers 32 and 34 through the apparatus.
The font retainer 56 is a solid element made from a material sufficiently strong to retain the lettering font element 20 in its printing position and to resist the upward movement of the piston assembly 47 during a printing cycle. The retainer 56 is a generally rectangular element having a channel or groove 55 on either side for sliding engagement with the corres-ponding rail members 58 and 60. In the preferred construction, the font retainer 56 is automatically moveable between an idle position illustrated in Figure 1 and a printing position illustrated in Figure 2. Movement of the retainer 56 to its idle position, shown in Figure 1, permits placement of the lettering font 20 into printing position and viewing of the previously printed character. Movement of the font retainer 56 to its printing posi-tion places it directly above the piston assembly 47 and font 20 to retain the font 20 in printing position and to resist the force created by the piston 47. The font retainer 56 is automatically programmed through an appropriate motor and cam mechanism (not shown) for sliding movement along the rails 58 and 60 between the positions illustrated in Figures 1 and 2.
Disposed to one side of the main frame, as shown in Figures 1 and

2 is a pair of supply rolls 36 and 38 which supply a color carrier 32 and an image carrier 34, respectively, to the printing station 22 positioned above the piston assembly 47. Although not specifically illustrated, each of the rolls 36 and 38 is supported for rotation about an axle or shaft journalled in the apparatus housing and each includes mechanical friction means which hold tension within the system and keep the rolls 36 and 38 from unwinding. The tapes or ribbons 32 and 34, fed from the rolls 36 and 38, ~05675Z
l pass through a portion of the main frame as illustrated in Figures 1, 2, 7 and 8 and extend past the printing station 22 at right angles to the movement of the font retainer 56. Specifically, as shown best in Figures 7 and 8, the tapes 32 and 34 pass between the frame members 11 and 12 and through an appropriate opening 23 (Figure 8) near the top of the pair of frame members 14. In the preferred construction, the color carrying ribbon 32 is positioned immediately above the image carrying ribbon 34 and is coated with a colored toner or other material which is transferred to the image carrier 34 during the printing cycle. The image carrier or tape 34 13 is comprised of a polyester material having a matte finish on one side for carrying the image and a pressure sensitive adhesive material on the other.
The adhesive backed surface is protected by a peel-away liner which is removed when the printing operation is completed and the printed tape 34 is desired to be used.
Associated with the ribbons 32 and 34 is a means 40 for advancing the ribbons through the printing apparatus and past the printing station 22. Such means 40 comprises a roll feed assembly having a pair of friction rollers 44 and 46 and a rotatable knob 42 connected with one of such rollers.
In the preferred embodiment, the manually rotatable knob 42 is connected 2~ with the friction roller 46. As can be seen, rotation of the knob 42 will result in movement of the ribbons 32 and 34 through the printing apparatus.
Specifically, rotation of the knob 42 in a counterclockwise direction will result in movement of the ribbons in a forward direction through the appara-tus, whereas rotation of the knob in a clockwise direction will result in backward movement of the ribbons. Although not illustrated in the drawings, the rollers 44 and 46 are appropriately supported by, and journalled in, the apparatus housing.
Positioned immediately below the printing station 22 and housed by the main frame elements 11, 12 and 14 is a piston assembly 47 which pro-vides the means for transferring a desired character from the color carrier 32 to the image carrier 34. The piston assembly includes a piston member 50 adapted for reciprocal movement within the piston housing, a cam element 54 l and a cam follower 53 The cam follower 52 is journalled within the lower end of the printing piston 50 and is adapted for rolling engagement with the cam element 54. The element 54 is mounted for r~tation with the shaft 53 which is rotatably supported within the frame elements 11 and 12 via suitable preloaded, tapered bearings 51. As the shaft 53 rotates, the cam element 54 engages the cam follower 52 resulting in recriprocal, up and down movement of the piston 50. Positioned at the upper end oE the piston 50 is a piston head 43 supporting a resilient printing pad 48. Althougll the pad 48 may be made from a variety of materials, in the present embodi-ment, such pad is made from a urethane material.
Adapted for placement immediately above the ribbons 3Z and 34 is a lettering font element 20 which is poisitionable in registration with the printing station 22. The font element-20 is a generally thin, rectangular element having a raised character 62 on the underside thereof and is insert-able above the ribbons 32 and 34 in the position shown in Figure 1. In this position, as best shown by Figure 7, the element 20 is supported by a shoulder portion 27 of a font nesting bracket 37, positioned on each side of the printing station 22 (Figure l). As shown, each of the nesting brackets 37, 37 has a beveled surface sloping downwardly and inwardly toward the shoulder portions 27. These beveled surfaces aid in seating the font element 20 in proper printing registration against the shoulders 27. The shoulders serve to properly support the element 20 and to align such element in the direction parallel to the movement of the ribbons 32 and 34 through the apparatus. Appropriate means are also provided in the form of a shoulder or stop member (not shown) to properly align the element 20 in the direction perpendicular to the movement of the ribbons 32 and 34.
The present structure also provides means for properly aligning the ribbons 32 and 34 relative to the printing station 22 and for guiding such ribbons through the printing station. Specifically, the means for guiding the ribbons 32 and 32 in a vertical direction, perpendicular to the flat surface of the ribbons comprises an elongated opening 23 (Figure 8) in the bracket 37. As shown in Figures 7 and 8, the ribbons 32 and 34 are 10567S;~

supported by the bottom surface of the opening 23 during movement of the ribbons through the apparatus. In the preferred embodiment, the ribbons are intended to be supported slightly above the resilient pad 48 (Figure 7) and the font element 20 is intended to be supported by the shoulders 27 slightly above the ribbons 32 and 32, This construction allows for relatively unrestricted movement of the ribbons through the printing appara-tus.
The guiding of the ribbons 32 and 34 in the lateral direction thereof is accomplished by a plurality of appropriately spaced holes 33 through the frame members 15 and 16 and two pairs of pin members 17 insertable into the holes 33. As shown best in Figure 8, the holes 33 extend through the frame members 15 and 16 and into the body of the apparatus to a point below the level at which the ribbons 32, 34 are supported. The particular spacing of cooperating pairs of the holes 33 are such that the distance therebetween corresponds to the standard widths of various sizes of ribbons 32, 34. The pins 17 are adapted for insertion into cooperating pairs of the holes 33 as shown in Figures 1, 2, 7 and 8 to guide the ribbons 32 and 34 therebetween.
Although the element 20 may be constructed from a variety of materials, it must be constructed from a material which is transparent and which is strong enough to permit such element to withstand the printing pressures generated during the printing cycle. As shown best in Figures 3 and 4, one edge of the element 20 includes a tab 66 bearing a representa-tion 68 of the raised character 62. Such tab 66 and representation 69 pro~
vide a ready identification of the raised character on the font element 20.
The element 20 also includes a plurality of indicia or index lines 64 which are visible to the operator of the apparatus during insertion of the ele-ment and advancement of the ribbons 32 and 34. The indicia 64 are spaced from certain portions of the lefthand edge of the character to be printed, each being generally equally spaced from adjacent indicia and equally spaced from portions of the lefthand edge of the character to be printed. Also, each of the indicia 64 is intended to generally follow dominant portions of the contour of the lefthand edge of such character 62. The purpose of such 1056~'SZ
1 indicia is to provide a means for properly spacing adjacent characters.
In understanding the advantages of the present invention, it should be realized that the adjacent characters in certain two letter or two character combinations have a tendency to interlock with one another as the result of the particular configuration of such characters. For example, in Figure 3, the letter "0", reference numeral 70, has a ten-dency to partially interlock with the letter "F" due to the fact that the letter "0" has a generally outwardly extending lefthand edge, whereas the letter "F" has a generally recessed righthand edge. If normal spacing techniques were utilized, which would be to space the leftmost edge of ~ the letter "0" relative to the rightmost edge of the letter "F", the letters "F" and "0" would visually appear to be too far apart. With the indicia lines 64 on the font element 20, however, proper positioning o~ such letters can be achieved with due consideration given to their interlocking nature.
As shown in Figure 3, this is accomplished by aligning one of the indicia 64 with the nearest portion of the righthand edge of the previously printed character. For example, in printing the letter "V" as shown in Figure 3, the ribbons 32 and 34 are advanced until the portion of the righthand edgc of the letter "0" is aligned with the particular indicium 64 being used. It is contemplated that the same index line will be used throughout the printing of any particular word or sentence to provide proper spacing. In the present example, the spacing of one index line is being used. The inventor has found that this will provide proper spacing of adjacent characters despite the interlocking nature of certain combinations.
In characters where the leftmost edge of the raised letter is generally a straight, continuous line, such as with the letters V, L, P, W, etc., the indicia 64 will be a series of generally equally spaced parallel lines such as is shown in Figures 3 and 5d. With characters such as the letters X, 0, C, etc., whose leftmost edge is substantially continuous, but not necessarily straight, the indicia 64 will comprise a series of generally equally spaced lines substantially following the contour of the lefthand edge of the character. Where the lefthand edge of the raised letter is not 1056'^~5'2 1 continuous, such as the letters J and Z as shown in Figures 5a and 5b, the indicia 64 will comprise a series of generally equally spaced lines sub-stantially following the contour of the dominant or characteristic portions of the lefthand edge of said character. For example, with the letter "J"
illustrated in Figure 5a, the dominant lefthand portions of such letter are the leading portion of the curved section and the upper, hori~ontally ex-tending cross section.
As illustrated in Figure 6, the full complement of letters, numer-als and various other characters are provided as a set 72 of font elements useable with the printing apparatus of the present invention. The set 72 of elements is normally contained within an appropriate box or container 74.
Having described the structure of the apparatus of the present invention in detail, the operation of such apparatus may be understood as follows: To begin with, the tapes 32 and 34 are threaded through the app-aratus 10 so that they are engaged by the ribbon advance assembly 40. At this stage, the font retainer 56 is in its idle position illustrated in Figure 1. The particular lettering font element or plate 20 bearing the character which is desired to be printed is then selected and inserted into the apparatus in the position illustrated in Figure 1. In this position, the various edges of the element 20 are engaged by appropriate alignment sur-faces and members insuring proper printing alignment of the font element 20.
The printing cycle is then commanced by appropriate external controls. The first step in the printing cycle is the movement of the font retainer 56 to the printing position illustrated in Figure 2. Next, the shaft 53 is rotated causing the cam member 54 to move against the cam follower 52 thereby moving the piston 50 and thus the resilient piston head 48 upward toward the raised character 62 on the lower side of the font element 20. Disposed between the piston head 48 and the raised character are the color carrier ribbon 32 and the image carrier ribbon 34. The upward movement of the piston 50 and piston head 48 is resisted by the font retaining element 56, causing the piston head 48 to exert a printing pressure against the raised character and resulting in tne transfer of an image of the raised character from the color carrier 32 ~(~56752 1 to the image carrier 34. To complete the printing cycle, the piston assembly 47 and the font retainer 56 automatically move back to their respective positions shown in Figure 1. The font element 20 is then manually removed and the element 20 displaying the next desired character is selected and inserted. The tapes 32 and 34 are then advanced by rotating the knob 42 in a counterclockwise direction until the righthand edge of the previously printed character is aligned with the particular index line 64 (Figure 3) being used. If a spacing of two index lines is being used, the righthand edge of the previously printed character should be aligned with the second index line 64 (Figure 3). The same spacing line or indicium 64 should be used for all adjacent characters throughout a particular printed composi-tion to maintain consistent spacing between the dominant adjacent edge portions of such characters. To facilitate the viewing of the previously printed character, the font element 20 is transparent. Thus the operator is able to visually align the previously printed character with the desired spacing line. When proper advancement of the tapes 32 and 34 and alignment of the previously printed character is achieved, the printing cycle is again com-menced, repeating the sequence described above.
Although the description of the preferred embodiment has been quite specific, it is contemplated that various modifications can be made to the apparatus of the present invention without deviating from the spirit of the present invention. It is therefore intended that the scope of the present invention be dictated by the appended claims, rather than by the description of the preferred embodiment.

3~

Claims (10)

1. A printing apparatus having means for providing proper spacing between adjacent printed characters, comprising a printing station;
an image carrier;
a color carrier;
a set of transparent font elements each comprising a relatively flat transparent plate having a single raised character thereon, each of said transparent plates being positionable in printing registration with said printing station and having visually detectable indicia for visually aligning said raised character relative to a previously printed, adjacent character, said visually detectable indicia comprising a plurality of horizontally spaced line segments on said transparent plate positioned to the left of, and between the vertical limits of, said raised character, and each of said line segments substantially following a portion of the leftmost contour of said raised character;
means for transferring an image of said raised character from the color carrier to the image carrier; and means for advancing said image carrier and said color carrier into printing alignment with said printing station.

2. The printing apparatus recited in claim 1 wherein said means for transferring an image of said raised character from the color carrier to the image carrier comprises:
means for exerting printing pressure against the raised character of said font element; and font retainer means for resisting movement of said font element during exertion of the printing pressure.

3. The printing apparatus recited in claim 2 wherein said means for exerting printing pressure comprises a piston assembly.

4. The printing apparatus of claim 3 wherein said piston assembly includes a resilient printing pad.

5. The printing apparatus of claim 4 wherein said printing pad is composed of a urethane material.

6. The printing apparatus recited in claim 1 further comprising means for manually advancing said image carrier and said color carrier into printing alignment with said printing station.

7. The printing apparatus recited in claim 1 further comprising means for aligning said font element in printing registration with said printing station wherein said means includes a plurality of alignment surfaces.

8. The printing apparatus of claim 1 wherein said indicia comprise a plurality of equally spaced line segments substantially following the leftmost contour of said raised character.

9. The printing apparatus of claim 1 wherein said indicia comprise a plurality of line segments substantially following character-istic portions of the leftmost contour of said raised character, said line segments being generally equally spaced from each other.

10. The printing apparatus of claim 1 wherein each of said trans-parent plates comprises a tab visible during the transfer of the image from said color carrier to said image carrier and bearing a represen-tation of said raised character on said transparent plate.