JPS6178659A - Printing head energizing time controlling apparatus - Google Patents

Abstract

PURPOSE:To automate the control of the energizing time to a printing head by providing the head control circuit equipped the head gap control mechanism by which the gap between a platen and the printing head being made variable and a convertion section by which a mechanical displacement action being converted to an electric signal. CONSTITUTION:A plate 5 and eccentric cams 7, 8 are rotated and a gap G between a printing head 2 and the platen 5 is varied by a rotation of an operation lever 9. The resistance value of a variable resistance 16 is varied by an integral rotation of a knob 17 thereof and the eccentric cam 8. A transister Tr1-Tr9 become ON when an electric source voltage is impressed to one electrode among the coils C1-C9 of the printing head 2, and a printing signal is inputted into the DOT1-C9. The electric current is flowed in the coils C1-C9 during a time corresponding to a time length of the output of the control circuit 20. It is possible to shorten a energizing time, to eliminate the loss of energy, to decrease noise and to save power consumption when one blank is printed, since the energizing time is proportional to the gap G positively.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a printing/rad energization time control device.

2. Description of the Related Art Conventionally, the gap between the print head and the platen has been adjusted in response to changes in the thickness and number of sheets of paper to be printed.

The adjusting means is for displacing the platen relative to the print head, or for displacing the print head relative to the platen.

Problems to be Solved by the Invention However, as described above, even if the gap is changed depending on the thickness of the paper and the number of sheets, the printing/adjusting time cannot be changed by the user. That is, a semi-fixed resistor is provided in the print head drive circuit, and the current application time is determined by adjusting the resistance value during adjustment before shipping. Therefore, when printing on a single sheet of paper, the printing pressure is too strong,
Power consumption increases and printing noise also increases.

The present invention has been made in view of these points, and includes a print head energization time control device that can automatically adjust the energization time to the print head when adjusting the gap between the platen and the print head. The purpose is to

Means for Solving the Problems This invention solves the problem by reducing the gap G between the platen 5 and the print head 2.
A head gap adjustment mechanism 6 that varies the head gap adjustment mechanism 6 is provided, and a head control circuit 20 that includes a conversion section 16 that converts the amount of mechanical displacement of the head gap adjustment mechanism 6 into an electrical signal is provided.

Therefore, the gap G is adjusted by the head gap adjustment mechanism 6, and the head gap adjustment mechanism 446 is linked to the converter 16, and the output of the converter 16 controls the energization time to the print head 2.

Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 to 3. A shaft 4 that slidably holds a carrier 3 on which a print head 2 is mounted is installed on opposing frames l. A head gap adjustment mechanism 6 that adjusts the gap G between the print head 2 and the platen 5
It consists of a pair of left and right eccentric cams 7.8 fixed to both ends of the shaft, and an operating lever 9 fixed to one of the eccentric cams 8. A protrusion 11 is formed at one end of the operating lever 9. The protrusion 11 is formed in the frame 1 to elastically engage with locking holes IO arranged in an arc having a radius around the center of rotation of the operating lever 9.

Next, a mounting plate [4] that holds the PC board 13 is fixed to the protruding piece 12 provided on the right frame 1 with screws 15.
This PCFi 13 holds a variable resistor 16 which is a converter. A protrusion 18 and a recess 19 that engage with each other are formed on opposing surfaces of the knob 17 of the variable resistor 16 and the eccentric cam 8.

The head control circuit 20 including the variable resistor 16 is a type of one-shot timer circuit. As shown in FIG. 3, the output side of the head control circuit 20 is connected to the base of a PNP type transistor Tro. This transistor T
The emitter of ro is for inputting the output ACL, and the collector is connected to resistors R1, R2...R9 and diode D, respectively.
t, C2...C9 to the base of an NPN transistor T'1°Tr2...Trs.The print head 2 is a dot printer head and is used to drive a plurality of needles individually. and a coil C+ of these magnets.

One pole of C2...C9 is a transistor T r
+ *Trz...Connected to the collector of Trs, and the other rods of coils C1, C2...C9 are connected to the power supply V via a common proton.
I(connected to transistors Tr+, Tr2
T'9's emitter is grounded.

In such a configuration, if the gap G is too large, the paper will vibrate, resulting in increased noise, and if the gap G is too small, the tip of the print head 2 will rub the paper. therefore,
Depending on the thickness and number of sheets of paper to be printed (Gap G
Adjust. When the operating lever 9 is turned, the platen 5 and the eccentric cam 7.8 are rotated, thereby changing the cap G between the print head 2 and the platen 5. Along with this, the knob 17 of the variable resistor 16 rotates integrally with the eccentric cam 8, so the resistance value changes, and the head control circuit 20 controls the energization time of the coils C1, C2...C9,\\ of the print head 2. is selected. That is, coils C1, C2・C
The power supply voltage is applied to one pole of 9, D○]'t, DOT
2,...DOT! When a print signal is input to transistor Tr1. When Tr2...Trs are ON, the coils Cs, C2...C9 are energized for a time corresponding to the output time of the head control circuit 20. This energization time and the gap G are in direct proportion to each other. Therefore, when printing on a sheet of paper, the energizing time is shortened, there is no wasted energy loss, noise is reduced, and power consumption is also reduced.

As a means for turning the knob 17 of the variable resistor 16, as shown in FIG.
1 may be fixedly provided on the frame 1 or the like.

Also, when using a thermal head as a print head, connect a heating element in place of coils C+, C2 and C9.
When using a daisy wheel, it is sufficient to control the energization time to the electromagnet that drives the printing hammer.

Effects of the Invention Since the present invention is constructed as described above, when the gap between the platen and the print head is changed, the printing/printing time can also be automatically changed, and therefore the thickness and number of sheets of paper can be changed automatically. The grab and printing pressure can be selected according to the printing conditions, thereby reducing printing noise, reducing power consumption, and making it possible to print clearly.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; Fig. 1 is a plan view, Fig. 2 is an exploded perspective view showing the mounting structure of the variable resistor, Fig. 3 is a circuit diagram, and Fig. 4 is the mounting of the variable resistor. FIG. 7 is a perspective view showing a modification of the structure. 2. Print head, 5. Platen, 6. Head gap adjustment mechanism, 16. Variable resistance (conversion section), 20.
...Head control circuit applicant: Tokyo Electric Co., Ltd. - 1

Claims (1)

[Claims] A head gap adjustment mechanism that adjusts the gap between the platen and the tip of the print head is provided, and a conversion section that converts the amount of mechanical displacement of the head gap adjustment mechanism into an electrical signal is provided, and the output of the conversion section causes the print head to be adjusted. 1. A print head energization time control device comprising a head control circuit that varies the energization time.