JPS6013560A - Shuttle type line dot printer - Google Patents

Abstract

PURPOSE:To accelerate a printing speed by efficiently taking out the response capacity of a printing hammer, by sliding a slide carrier having a printing hammer unit at an equal speed during passage through a printing region. CONSTITUTION:By providing a shuttle mechanism constituted of a slidable slide carrier 9 having a printing hammer unit 8 moved thereto, a plate cam 6 having a shape along which the slide carrier 9 is slid at an equal speed during passage through a printing region, two cam followers 10, 11 which convert the rotary motor of the plate cam 6 to a linear motion while grasping said plate cam 6 to transmit the same to the slide carrier 9 and fixed to the slide carrier and damper springs 15, 16 for absorbing the vibration impact of the slide carrier 9, the slide carrier 9 having the printing hammer unit 8 mounted thereto is allowed to slide at an equal speed when passes the printing region.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shuttle type line head printer in which a printing hammer unit can slide at a constant speed across a printing area.

Conventional shuttle-type line head printers use a plate cam that is eccentric to the rotating shaft by the amount necessary for the sliding amplitude, or an eccentric cam that is equipped with a link, in order to slide the carrier on which the printing hammer unit is attached.

Printing was performed using a shuttle mechanism that slid the carrier using an eccentric crank system. In these cases, if the angular velocity of the rotating shaft equipped with the eccentric cam and eccentric crank is W and the amount of eccentricity is A, then the shuttle displacement X is z =
It is expressed as A si,n wt, and when time t is used as a parameter, it becomes a sinusoidal motion.

For this reason, in a shuttle type line head printer using an eccentric cam and eccentric crank system, the speed of the sliding carrier changes with respect to time t at x = AW Co5wt, so the printing hammer mounted on the sliding carrier is , it is necessary to set the response frequency so that it can respond at the maximum speed when the sliding carriage passes through the printing area, which results in wasteful setting of the response frequency of the printing hammer, and the shuttle type line dot printer cannot be used at high speeds. This was a problem when it came to becoming a

The present invention has been developed in view of the above-mentioned drawbacks, and includes a slidable sliding carrier to which a printing hammer unit is attached, and a plate cam having a shape such that the sliding carrier slides at a constant speed when passing through a printing area. and two cam followers fixed to the sliding carrier that sandwich the plate cam and convert the rotational motion of the plate cam into linear motion and transmit it to the sliding carrier;
By providing a shuttle mechanism composed of a damper spring that absorbs the vibration impact of the sliding carrier,
To provide a shuttle-type line head printer in which a sliding carrier, that is, a printing hammer unit, is kept at a constant speed when passing through a printing area, and the response performance of the printing hammer is efficiently brought out to enable high-speed printing.

The present invention will be described below based on embodiments shown in the drawings.

Fig. 1 shows an external view of the device to which the present invention is applied, Fig. 2 shows the cam profile of the plate cam, Fig. 3 (2),
(B) and C) illustrate the operating principle of the shuttle mechanism. Referring to FIG. 1, the embodiment of the present invention transmits the rotational motion of a motor 1 as a power source to a camshaft 5 through three gear trains 2, 3.4, thereby causing the camshaft 5 to rotate.

A plate cam 6 having a cam profile shown in FIG. 2 and an encoder 7 are mounted on the camshaft 5.

The plate cam 6 is sandwiched between two cam followers 10 and 11 which are composed of ball bearings and shafts fixed to a sliding carrier 9 on which the printing hammer unit 8 is mounted, and the sliding cam structure is The rotational movement of the plate cam 6 is transmitted to the sliding carrier 9 as a linear movement. The sliding carrier 9 is mounted on two shafts 13, 14 fixed to the frame 12 and slides in the axial direction.

Two damper springs 15°16 wrapped around the shaft 13
absorbs vibration shock during shuttle operation of the sliding carrier 9.

The optical sensor 17 and the encoder 7 still detect the dot printing position of the print mark unit 8 during the shuttle operation and control the printing.

Next, the principle of operation of the shuttle mechanism will be explained with reference to FIGS. 2 and 3, CB) and C). At time 0 in FIG. 2, the sliding carrier 9 is at the left end as shown in FIG. 3. At this point, the plate cam 6 is held in the rotational position shown in the figure by the two cam followers 10.11 fixed to the sliding carrier 9. Also, two damper springs 15 and 16 are wound around the shaft 13 to which the sliding carrier 9 is attached, and the damper springs 15 are compressed by the frame 12 and the sliding carrier 9, giving a rightward force to the sliding carrier 9. . The damper spring 16 is
It is pulled by the sliding carrier 9 and the frame 12 and applies a rightward force to the sliding carrier 9 similarly to the damper spring 15.

Next, when the plate cam 6 rotates until time t1 shown in FIG. 2, the sliding carrier 9 is accelerated and reaches a constant speed, and thereafter slides at a constant speed until time t2. During this time, the sliding carrier 9 passes through the printing area, and if the required number of dots is n, this passing time is 1. The time ΔT obtained by dividing 11 into n-1 equal parts becomes the response period of the printing hammer. The important point here is that by making the sliding carrier 9 move at a constant speed during the printing time, the number n of dots to be printed during the printing time can be divided by an equal time ΔT, and the response frequency of the printing hammer can be maximized. The reason is that the settings can be set efficiently.

Now, when the sliding carrier 9 passes time 12, a negative acceleration is applied to the plate cam 6 and the cam follower 10 in the direction of movement.
At time T/2, the velocity becomes 0 and the right end position is reached as shown in FIG. 30. At this time, the sliding carrier 9 receives a leftward force from the two damper springs 15 and 16.

Then, when the plate cam 6 further rotates, the sliding carrier 9 is accelerated from right to left and reaches a constant speed at time t3 as in the outward path, and thereafter slides at a constant speed until time t4, passes through the printing area, and reaches the time t4. After passing 14, the sliding carrier 9 receives acceleration from the left to the right, and at time T, the speed becomes zero again and returns to the left end position. Thereafter, in the same manner, the sliding carrier 1 shuttles at a period T and prints one line at a time on each outbound trip.

As described above, according to the present invention, the sliding carrier on which the printing hammer unit is attached is configured to slide at a constant speed when passing through the printing area, so that the response performance of the printing hammer can be efficiently brought out and the printing This has the effect of speeding up the process.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of an embodiment of the shuttle type line head printer of the present invention, Fig. 2 is a cam profile of a plate cam, and Fig. 3 (4), @, 0 is an explanatory diagram of the operating principle of the shuttle mechanism. . 6... Printing hammer unit for plate cam 8 9... Sliding carrier 10.11... Cam foo 715.16.
...Dampus Fring Applicant NEC Corporation Figure 1 Figure 3

Claims (1)

[Claims] A sliding carrier to which a printing hammer unit is attached, a plate cam having a shape such that the sliding carrier slides at a constant speed when passing through the printing area, and a rotational movement of the plate cam by sandwiching the plate cam. The shuttle mechanism includes two cam followers fixed to the sliding carrier that converts the linear motion into a linear motion and transmits the linear motion to the sliding carrier, and a damper spring that absorbs the vibration impact of the sliding carrier. This is a shuttle-type line-tod printer that is characterized by: