JPH0253236B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a multicolor ribbon mechanism used in a printing mechanism;
In particular, it relates to a multicolor ribbon cassette mechanism used in matrix printers.

In most types of printing mechanisms, from simple typewriters to complex printers, ribbon movement is accomplished by supporting a portion of the ribbon on a rotating bail arm that raises and lowers the ribbon to the appropriate color band. This is done by aligning the printing mechanism. The bail arm supports the ribbon so that it operates in a plane parallel to the print medium (such as print paper, hereinafter referred to as print paper). A mechanism for manipulating a ribbon cassette having two colors is disclosed in Depew, US Pat. No. 4,088,218. The mechanism is specifically designed for use with matrix printheads, and the body has a chamber for storing the ribbon. The ribbon passes around a pivoting extension that moves the ribbon up and down within the cassette.

The pivoting bail arm method generally works well when only two colors are used, but excessive up-and-down movement of the ribbon can cause tearing and ribbon feed retardation; This is particularly likely to occur when the ribbon is loaded into a cassette. Therefore, it is a primary object of the present invention to provide a ribbon cassette mechanism that operates smoothly and is readily available for more than two colors. A further object of the present invention is to provide a simple and straightforward ribbon moving mechanism. It is also an object to provide a mechanism by which it can be determined whether a cassette is in place and what type of cassette is being used.

These objectives can be achieved by providing a device in which the entire ribbon cassette pivots about an axis perpendicular to the print sheet. Unlike prior art devices, movement of the ribbon is not accomplished by translational movement of the ribbon, but by rotation of the cassette. By moving the entire ribbon section, it is possible to remove ribbon tears and the like. The entire ribbon cassette is moved to change the color, and the mechanism is extremely simple.

The system is particularly useful for use with matrix printers having printheads mounted on carriages. Other printers that can utilize the present invention include ball and daisy wheel printers. The pivot plate is pivotally mounted at one end to the carriage for rotation about an axis perpendicular to both the print sheet and the portion of ribbon in the print position. The ribbon cassette is removably installed on the pivot plate. A ribbon drive motor is fixed to the bottom of the pivot plate and feeds the ribbon within the cassette. By pivoting the pivot plate, each portion of the ribbon fed within the cassette can be positioned in alignment with the print head. The ribbon pivots about an axis perpendicular to the print sheet, so that even as the ribbon moves, it remains parallel to the print sheet.

Movement of the pivot plate is controlled by a cylinder cam driven by a step motor. The cylinder cam and step motor are mounted on a carriage, and the cam is coupled to the pivot plate by a cam follower. The position of the cam is controlled by appropriate logic circuitry. It is also possible to perform positioning using other positioning tools such as a movable inclined surface. However, the cam arrangement facilitates accurate positioning of the ribbon cassette with respect to the printhead.

The present invention will be described in detail below with reference to the drawings.

1 and 2, a printer 10 includes a wire matrix printhead 12 mounted on a carriage 14. As shown in FIGS. The print head 12 is offset relative to the front portion 14a of the carriage. The carriage includes a pair of rails 16 fixed to a frame 18.
move along. Ribbon cassette 20 is mounted on a carriage and has an opening 20a through which print head 12 extends. Ribbon cassette 20 is ribbon 2
2, and its exposed portion 22a is placed in front of the print head parallel to the printing paper 24.

2, 3 and 4, the ribbon cassette 20 is mounted on a pivot plate 26 and is removable. Pivot plate 26 functions to determine the position of the ribbon cassette relative to printhead 12. The pivot plate 26 is pivotally attached to the carriage 14 by a pair of hinges 28 so that the pivot plate 26 can pivot about an axis perpendicular to the printing paper 24 and the exposed ribbon portion 22a. With this arrangement, even if the pivot plate 26 and the ribbon cassette 20 pivot,
The exposed ribbon portion 22a remains parallel to the printing paper 24. By pivoting the pivot plate 26,
Portions of different heights of the exposed ribbon portion 22a can be aligned with the front portion 12a of the printhead. The ribbon 22 is fed by a ribbon drive motor 38 located on the underside of the pivot plate 26. This allows the ribbon 22 to be fed within the cassette 20 even when the pivot plate 26 is in an inclined position. Even if the cassette 20 is tilted, the printing operation of the printer will not be impaired. In all cases, the exposed ribbon portion 22a remains parallel to both the front surface of the printhead 12 and the printing paper 24.

The position of the pivot plate 26 is controlled by a cylinder cam 32 fixed to the carriage 14. The cylinder cam 32 is driven by a motor 36 and is connected to the pivot plate 26 by a rod-shaped cam follower 34. cam 32
The groove 32a has a helical groove 32a having four flat rests defining four different print positions (FIG. 5) on the ribbon cassette 20. The cam follower 34 has a protrusion 34a that cooperates with the spiral groove 32a.
and a protrusion 3 extending into the notch 26a of the pivot plate.
4b. In the embodiment of the present invention, the cam 32 is rotated by a motor 36, which is a step motor, so that the cam follower 34a is moved into the helical groove 34.
It is located on one of the four flat parts of a. The flat portion positions the ribbon at an accurate height even if there is some error in the position of the motor, and prevents rotation of the cam 32 due to downward force on the cassette 20. Motor 36 is controlled by appropriate logic circuitry 39. In the embodiment of the present invention, the logic circuit 39
When power is supplied to the printer 10, the command commands the cassette 20 to be placed in a horizontal position by moving the follower 34 downward four times. If the cassette 20 is already down, or down several steps, the motor 36 will be stopped for all or some of the four movement commands. Once this initialization process is complete, logic circuit 39 knows that cassette 20 corresponds to band 1 of ribbon 22 and remembers its position as long as power is applied. FIG. 5 shows the position of the four bands of ribbon 22 relative to the front of printhead 12a corresponding to each position of cam 32. If ribbon cassette 20 is horizontal, band 1 of ribbon 22 will be aligned with print head 12a, and if cassette 20 is tilted to the top, band 4 of ribbon 22 will be aligned with print head 12a.

Two different types of ribbon cassettes can be used in embodiments of the invention. 1st
The model consists of four separate color bands with four color printing capabilities. The second type consists of a black-only (or other solid color) ribbon. Both types of cassettes utilize ribbons having the same width (2.54 cm). A two step process is performed to automatically determine which type of cassette has been loaded. Each ribbon cassette has a protrusion 40 extending from the bottom of the cassette. When the pivot plate is in the horizontal position, the protrusion 40 is sensed by an optical sensor 42 located on the carriage 14. Once it is determined that the ribbon cassette is properly positioned, the pivot plate is raised two steps and the sensor 42 is moved angularly. The height of the protrusion 40 for a cassette with four colored ribbons is shorter than the height of the protrusion for a cassette with a single colored ribbon. The height of the protrusion in the case of a single color is indicated by a dotted line 40a in FIG. When the pivot plate is in the raised position, the sensor 42 senses only the higher of the two protrusions. Logic circuit 39 receives information from sensor 42 to determine the presence and type of cassette in use.

In summary, the present invention is directed to a simple and effective method for utilizing multicolored ribbon cassettes in a printing mechanism. Although the invention has been described for use with matrix printers, it may also be used with other types of printers. By repositioning the entire cassette instead of moving just a portion of the ribbon, loading the cassette is much easier and requires no special manipulation of the ribbon (such as threading the ribbon through the bail arm). ) is not necessary. The device can easily operate with more than two colors, even if there are considerable distances between the color tracks. Additionally, the present device provides more accurate positioning than typical bail devices.

Although this mechanism has been described in terms of one embodiment, modifications and changes will be readily apparent to those skilled in the art. For example, a rotating bar, solenoid or cable could be used instead of a step motor. Therefore, the scope of the present claims is intended to include such modifications.

[Brief explanation of drawings]

FIG. 1 is a partial perspective view of the printing device when the multicolor ribbon cassette device of the present invention is in the lowest position, FIG. 2 is a plan view of the ribbon cassette of the present invention, and FIG. 3 is a multicolor cassette of the present invention. 4 is a side view of the multicolored ribbon cassette apparatus of the present invention, and FIG. 5 shows the ribbon position for each cam position and the trajectory of the cam used to control the ribbon cassette position. FIG. 6 is a partial perspective view of the printer device showing a state in which the ribbon cassette device is tilted. 10...Printer, 12...Print head,
14...Reciprocating stand, 20...Ribbon cassette, 22
... Ribbon, 26 ... Pivoting plate, 32 ... Cam, 3
2a...Spiral groove, 36...Motor.

Claims (1)

[Scope of Claims] 1. A carriage for moving a print head perpendicular to and across the print medium; and a pivot plate having one end pivotally connected to the carriage about an axis perpendicular to the print medium. , a cam motor fixed to the reciprocating table; a cylindrical cam having a substantially spiral cam groove having a plurality of flat portions on its peripheral surface and attached to the cam motor; and a cam groove of the cylindrical cam and the pivot. A cam follower that communicates with the moving plate; and a ribbon cassette that is detachably attached to the pivot plate and stores the ribbon so that a part of the ribbon moves parallel to the printing medium. , rotation of the cylindrical cam causes the pivot plate to pivot clockwise or counterclockwise, thereby adjusting the position of the ribbon cassette with respect to the print head while maintaining the ribbon in a plane parallel to the print medium; A printer's multicolor ribbon cassette mechanism that allows the ribbon to be changed in multiple positions.