JPH0222289Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a pulley device for differential feeding of a printer.

(Prior Art) In a printer that guides paper between a print head and a platen having an ink-impregnated body made of a sintered body of nylon or the like impregnated with ink, and prints by applying pressure from the print head, the above type of printer is used. It is extremely difficult to manufacture a platen with a long effective printing area due to accuracy issues. Therefore, in conventional printers of the above-mentioned type that print on wide printing paper, the relatively short printer and print head are synchronized and moved at a constant speed, instead of using a long platen with an effective printing area that spans the entire width of the printing paper. Printing was performed while the machine was running.

This type of printer performs printing while moving the platen and print head at a constant speed, and in particular, when the print head is of the wire dot impact type, the following problems occur.

First, when a wire impacts the sintered body of the platen through the printing paper during printing, the surface of the sintered body is deformed and dented.

A single impact will recover the dents in the sintered body, but if the same spot is impacted continuously, the dents will not recover, and the surface of the sintered body will become uneven.

If printing continued in this state, the printed portion of the paper would become abnormally depressed, and furthermore, there would be holes in the paper.

At the same time, there was a problem in that the recesses caused by continuous impact caused a delay in the supply of ink, causing the printed color to become pale and uneven printing to occur.

In order to deal with this problem, as shown in the specification of the patent application ``Dot Impact Printer'' filed on May 27, 1980, filed by the same applicant as the present invention, the platen and the print head are arranged so that the print line is so that they move together while changing their relative positions in the longitudinal direction,
Techniques have been proposed to make effective use of the effective printing range of the platen. That is, as shown in FIG.
The rotation of the pulley 6 in the direction of the arrow B in the same figure causes it to be fed laterally in the direction of the arrow C in the same figure, and the platen 7
The holder 10 guided by the square shaft 8 and the shaft 9 rotates the pulley 12 in the direction of the arrow B in the figure through the wire 11, changing the relative position with respect to the print head 1 in the figure D. It is designed to be fed horizontally in the direction of the arrow.

For details, refer to FIG. 2. In the figure, the positional relationship between the print head 1 and the platen 7 is such that when printing from left to right on the print paper 13, the left edge of the maximum printing width of the print paper 13 is Position E
The position of the tip 1a of the head 1 is adjusted to be at the left end of the effective printing width of the platen 7, and the pulley ratio of the pulley 12 to the pulley 6 is such that the maximum printing width of the printing paper 13 is L, and the width of the platen is It is set to be (L-l)/L, where l is the effective printing width.

When the motor 14 is rotated in the direction of the arrow B in FIG. 1 in this state, the head 1 and the platen 7 are moved in the direction of the arrow C and the direction of the arrow D, respectively. When the head 1 comes to the platen 7, the position of the tip 1a of the head 1 is
Therefore, according to the conventional example, the effective printing range of the platen 7 can be used effectively, and all problems caused by continuous impacts on the same part of the platen can be solved. It was hot.

According to the conventional example, the diameter of the pulley 12 is the same as that of the motor 1.
4 and the unit feed amount of the print head 1 (the unit feed amount of the print head 1 is determined by the dot configuration of the characters to be printed).As mentioned above, the pulley ratio is (L- l)/L
Therefore, as l becomes larger, the diameter of the pulley 12 becomes smaller than the diameter of the pulley 6. When connecting the wire 11, etc. to the pulley 12 as shown in FIG. When the diameter of the wire becomes smaller than the winding diameter, stress is applied to the wire and problems such as cutting occur.

To deal with this problem, as shown in FIG. 3, a print head pulley 20 and a platen pulley 21 are used.
The diameters of both are set to satisfy the minimum winding diameter of the wires 22 and 23, the pulley 20 is fixed to the output shaft 25a of the motor 25 together with the integral gear 24, and the pulley 21 is fixed to the support plate 27 together with the integral gear 26. A gear 31 rotatably supported on a shaft 28 fixed to a frame 29 and rotatably supported on a shaft 30 fixed to a frame 29 is meshed with both the gear 24 and the gear 26. A conceivable method is to reduce the speed relative to the printing speed, move the printing head horizontally using the wire 22, and feed the platen horizontally using the wire 23.

According to this method, no force is applied to the wire 23, but in the structure shown in the figure, the wire 23 is assembled with a certain amount of tension, and the pulley 21 receives force from the wire 23 and rotates about the shaft 28. Therefore, the space between the inner diameter of the pulley 21 and the shaft 28 is likely to wear out, resulting in an undesirable problem in terms of durability.

(Purpose) The purpose of the present invention is to guide printing paper between a printing head and a platen having an ink-impregnated body made of a sintered body impregnated with ink, so that the platen and the printing head are connected during printing. In a printer that moves in the same direction while changing the relative position in the longitudinal direction of the print line, and prints by adhering ink to print paper by applying pressure from the print head, a print head that moves the print head horizontally via a wire. A pulley for a platen that drives a platen is rotatably supported via a wire with respect to a drive shaft to which a pulley for a platen is fixed, and the pulley for a platen is rotated in the same direction as the drive shaft via a gear train. By reducing the relative speed between the drive shaft and the drive shaft,
The diameter of the pulley for the platen can be set through the gear ratio of a gear train that can be freely selected relative to the diameter of the pulley for the print head, so that the diameter of the platen pulley easily satisfies the minimum winding diameter of the wire. At the same time, by reducing wear between the platen pulley and the drive shaft as much as possible, the durability of the pulley mechanism including the platen pulley and wire is greatly improved.

(Example) The present invention will be explained below with reference to an example. In FIG. 4, a frame 40 includes a motor 41 and a shaft 42.
is fixed to the output shaft 41 of the motor 41 which is the drive shaft.
A print head pulley 44 integrally formed with a gear 43 is fixed to a, and a wire 45 is wound around the pulley 44 to horizontally feed a print head (not shown).

The gear 46 is formed integrally with the gear 47, and the shaft 42
The gear 46 is rotatably supported by the gear 4.
It meshes with 3. The output shaft 41a also has a gear 4.
A platen pulley 49 integral with the platen 8 is rotatably supported and thrust-stopped by retaining rings 50 and 51, the gear 48 meshes with the gear 47, and a wire 52 is wound around the pulley 49 to connect the platen (not shown). It is now possible to feed the paper sideways.

(Operation) The operation of the embodiment of the present invention will be explained below.
When the pulley 44 is rotated by the rotation of the output shaft 41a, the pulley 49 is decelerated through a gear train consisting of gears 43, 46, 47, and 48, and is rotated in the same direction. Therefore, the pulley 49 is the output shaft 4
1a, the speed difference between the pulley 44 and the pulley 49 causes it to rotate in a direction relatively opposite to the rotation direction of the pulley 44, so its relative speed is smaller than the rotation speed with respect to the fixed shaft in the conventional example. Become.

Furthermore, since the reduction ratio of the gear train can be freely selected within a practically sufficient range, the diameter of the pulley 49 is no longer restricted by the diameter of the pulley 44 as in the conventional example, and the diameter of the pulley 49 can be set freely. be able to. Therefore, the diameter of the pulley 49 can be set so as to satisfy the minimum winding diameter condition of the wire 52.

(Effects) As described above, according to the present invention, printing paper is guided between a printing head and a platen having an ink-impregnated body made of a sintered body impregnated with ink, and the printing paper is guided between the printing head and the platen. In a printer that moves in the same direction while changing the relative position in the longitudinal direction of the print line, and prints by applying pressure on the print head to apply ink to the print paper, this is a printing method in which the print head is moved horizontally via a wire. A platen pulley that drives the platen is rotatably supported via a wire to a drive shaft to which a head pulley is fixed, and is rotated in the same direction as the drive shaft via a gear train. By reducing the relative speed between the pulley and the drive shaft,
The diameter of the platen pulley can be set using the gear ratio of the gear train, which can be freely selected relative to the diameter of the print head pulley, so the diameter of the platen pulley can easily be set as the minimum wire winding diameter. Since the wear between the platen pulley and the drive shaft is reduced as much as possible, the durability of the pulley mechanism including the platen pulley and wire can be greatly improved. etc., remarkable effects can be obtained.

[Brief explanation of drawings]

Figures 1 to 3 relate to a conventional example, Figure 1 is a perspective view showing the main parts of the printer including a pulley mechanism for differential feeding, and Figure 2 is the positional relationship of the head, platen, and printing paper in the printing direction. Figure 3 shows the first
Figure 2 shows a differential feeding pulley mechanism between the print head and platen of a printer according to a conventional example different from Figure 2; It is a figure which shows the pulley mechanism for differential feeding. 41a is a drive shaft, 43, 46, 47, 48 are gears, 44 is a print head pulley, 45 is a wire,
49 is a pulley for the platen.

Claims (1)

[Scope of utility model registration request] The printing paper is guided between a printing head and a platen having an ink-impregnated body made of a sintered body impregnated with ink, and the platen and the printing head move together while changing their relative positions in the longitudinal direction of the printing line during printing. In a printer that moves in the same direction and prints by adhering ink to the print paper by pressurizing the print head, a drive shaft 4 is fixed with a print head pulley 44 that transports the print head laterally via a wire.
A platen pulley 49 for driving the platen 1a is rotatably supported via a wire 52, and a gear 43 integrally formed with the print head pulley 44 rotatably supports a fixed shaft 42. The platen pulley is rotated in the same direction as the drive shaft 41a through a gear train consisting of supported gears 46, 47 and a gear 48 integrally formed with the platen pulley 49, and the drive shaft 41 is rotated in the same direction as the drive shaft 41a.
A pulley mechanism for operating and feeding a printer, characterized in that the relative speed of a platen pulley 49 with respect to a is reduced.