JPS5915831B2 - printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printer that is most suitable as a recording output machine for small office equipment such as a calculator or an electronic cash register.

5 Conventionally, for example, in a typical line printer, multiple types of type are printed on a continuously rotating type drum (
Each hammer is aimed with a solid hammer, and each hammer is carried within the rotation trajectory of the pawl of a continuously rotating ratchet wheel by an actuator 10 of an electromagnetic solenoid whose trigger lever is activated by the arrival of a print signal. Type wheels are configured to be elastically driven in the direction of the type drum by applying a sudden impact force with the claws, or a plurality of type wheels are provided, and 15 types can be placed on each type wheel. There are configurations in which each type wheel is selectively stopped and printed all at once using a common hammer, or the selected and stopped type wheel itself is pressed against a platen to print.

However, although these printing devices have reached almost the desired level in terms of printing speed, they have a complex structure and a large number of parts, and are still unsatisfactory in terms of maintenance, inspection, and economic efficiency. These shortcomings cannot be overlooked in the case of small office equipment, which has become rapidly popular and inexpensive in recent years. For this reason, in the last 25 years, a line printer has been invented that has a simple structure, has a small number of parts, and is fully satisfactory in terms of maintenance, inspection, and economic efficiency, and has filed an application as Japanese Patent Application No. 51-1134772. Therefore, the present invention adds 30 further improvements to the above-mentioned application, prevents the printing operation time based on the arrival of a printing command from greatly varying due to the elastic flexibility of mechanical components, and makes it suitable for high-speed printing. The purpose is to provide a printer that can

The present invention will be explained in detail below with reference to an embodiment shown in the drawings. In the drawings, reference numeral 1 denotes a machine frame, on which a type drum 2 made of an elastic material such as hard rubber is rotatably installed horizontally, and on the circumference of the type drum 2 there are printed characters 3 of a plurality of digits, for example, 14 digits. is engraved, and each digit is the type 3 above.
As can be understood from FIG. 2, the type characters 3 in adjacent digits are arranged in a staggered manner. Reference numeral 4 denotes an ink roller, which is installed on the machine frame 1 and normally comes into pressure contact with the type drum 2, and is rotated by the friction thereof to apply ink to the type characters 3.

Reference numeral 5 denotes a leaf spring formed by cutting a single spring material board to the same number as the number of digits mentioned above, and these common side parts 5a are integrated into a base 6 made of synthetic resin by insert molding, and the base It is supported by the machine frame 1 via 6.

Print hammers 8 made of synthetic resin are inserted into the free end of each of these leaf springs 5 facing the type drum 2, facing each digit position of the type drum 2 with a printing paper 7 interposed therebetween, and arranged in the direction of the digits. These printing hammers 8 are integrally supported by molding, so that the printing hammers 8 can be independently biased to move toward the printing position. 9 is the same number of first leaf springs as the number of digits, 10 is a second leaf spring facing each of these first leaf springs 9, and these are all made by cutting a single spring material board. The base ends of the common sides are connected to a support column 11 made of synthetic resin by insert molding, and the support column 11 is horizontally installed on the machine frame 1.

Particularly in this case, the thickness of the first leaf spring 9 is set to be thicker than that of the second leaf spring 10, so that when it is pressed by an eccentric cam, which will be described later, it can easily move around its pressing part. It is designed to prevent elastic bending. As a result of this configuration, the first leaf spring 9 and the second spring 10 form a set, and the same number of leaf springs as the print hammers 8 are provided. The free ends of the first leaf spring 9 and the second leaf spring 10 are bent into a semicircular shape for the purpose of increasing strength, and are positioned so as to sandwich one print hammer 8 from above and below. tip 9a,
10a can be engaged with the engagement steps 8a, 8b of the print hammer 8, and the print hammer 8 is held in the rest position when at least one of them is in the engaged state. . Reference numeral 12 denotes a first cam group, which is composed of a plurality of eccentric cams 12a located between the first and second leaf springs 9 and 10, respectively, and corresponding to the girders. The second leaf springs 9 and 10 are moved vertically alternately by elastic deformation in the vicinity of the support column 11, and the tip portions 9a and 10a of the second leaf springs 9 and 10 are connected to the engagement step portions 8a and 8b of the print hammer 8. The eccentric cams 12a are designed to alternately release the engagement between each other, and in particular, the eccentric cams 12a are arranged at an angle of 180 degrees from each other so that the releasing operation is in opposite phase between the sets corresponding to adjacent digits. Their eccentric directions are set to be opposite to each other so that they have a phase difference.

Reference numeral 13 denotes a second cam group consisting of 14 eccentric cams 13a that can come into contact with the intermediate portions of the leaf springs 5 corresponding to each digit,
With the rotation of these eccentric cams 13a, the print hammer 8 is forcibly returned from the printing position to the rest position against the spring force of the leaf spring 5. In particular, the return action is effective against the spring force of the leaf spring 5. In order to perform the rotation in opposite phases, the eccentric cams 13a are set such that their eccentric directions are opposite to each other so that adjacent eccentric cams 13a have a phase difference of 180 degrees. .

14 is one set of leaf springs 9, 10 forming the pair.
and the other set of leaf springs 9 and 10 adjacent to each other in digit correspondence, one electromagnetic solenoid is provided for every two sets, and each of these one electromagnetic solenoid 14 is wound by an electromagnetic coil 15. Two solenoid cores 1
6, and each of the 14 solenoid cores 16 is a synthetic resin-made solenoid core 16 installed upright on a printed circuit board 17 disposed on the machine frame 1 at a position facing each of the second leaf springs 10 below. The engagement pieces 18 are held by engagement means so as to be arranged in the digit direction.

Reference numeral 19 denotes a print guard disposed in the machine frame 1 so as to substantially surround the type drum 2 and ink roller 4 to prevent printing paper from becoming dirty; 20 indicates the print guard so as to form a paper guide path 21 for guiding the printing paper 7; 19 and a paper guide provided in opposing relation to each said type drum 2.
There are openings 22, 2 in the area facing the print hammer 8.
3 is formed.

24 is a paper feed roller, and 25 is a drive motor, which serves as a drive source for the type drum 2, the first cam group 12, the second cam group 13, and the paper feed roller 24.

In the above, the type drum 2, the first and second cam groups 1
2 and 13 are constantly rotated, and the first cam group 1
2 and the second cam group 13 have the same rotational speed, and the time required for one rotation of the first cam group 12 is equal to the time required for one rotation of the first cam group 13. It is set to be the same as the time required to travel in minutes. Next, the printing operation of the line printer having the above configuration will be explained using one digit as an example.

That is, as the eccentric cam 12a of the first cam group 12 rotates, the first leaf spring 9 and the second leaf spring 10, which is in a pair of relationship opposite to the first leaf spring 9, rotate their tip portions 9a, 10a. Engagement stepped portion 8a of print hammer 8,
8b and the operation of alternately releasing the engaged state are repeated. As long as these three states are repeated, the print hammer 8 is held at the rest position. Then, the print signal is synchronized with the eccentric cam 12a, and the second leaf spring 10 is synchronized with the eccentric cam 12a.
When pressed downward, that is, to the disengaged position, by the electromagnetic solenoid 14, the electromagnetic solenoid
4 attracts the pressed second leaf spring 10 with its solenoid core 16 and holds it in the disengaged position. In this held state, the first leaf spring 9 is moved upward by the continued rotation of the eccentric cam 12a, disengaging its tip 9a from the engagement step 8a of the print hammer 8. Then, the print hammer 8 is rapidly moved onto the type drum 2 by the spring force of the leaf spring 5, and the printing paper 7 is
A predetermined type 3 is struck through the holder to perform printing. The eccentric cam 13a of the second cam group 13 is sufficiently far away from the leaf spring 5 immediately before the above-described hitting action of the print hammer 8 is performed. After the above beating action is completed,
The eccentric cam 13a resists the spring force of the leaf spring 5 and moves the print hammer 8 between the tips 9a and 10a of the leaf springs 9 and 10, where the opposing distance has already been restored to the minimum due to the rotation of the eccentric cam 12a. The print hammer 8 is forcibly moved from the print position to the print body stop position as if inserted, and the print hammer 8 connects its own engagement steps 8a, 8b with the respective tips 9a, 10a of both leaf springs 9, 10. Engagement is restored and ready for the next printing operation. The same printing operation as above is performed for multiple digits, but in that case, the printing operation is performed for the digits that are in the preceding phase relationship, and then the printing operation is performed for the digits that are in the opposite phase relationship, and this After printing one line in this manner, the printing paper 7 is fed one line. Now, in the printing operation as described above, in order to release the engagement between the tip end 9a of the first leaf spring 9 and the engagement stepped portion 8a of the print hammer 8, the eccentric cam of the first cam group 12 When the first leaf spring 9 is elastically bent around the pressure-receiving portion when receiving a pressing force pushed upward by the spring 12a, the gap between the tip portion 9a and the engagement step portion 8a is This causes temporal variations such as time delays in the disengagement operation.

In particular, this phenomenon occurs when the second leaf spring 10 is held in the disengaged position by the electromagnetic solenoid 14 that receives the print signal, and in this state, the print hammer 8 is engaged in the rest position only by the first leaf spring 9. This is likely to occur if the engagement pressure between the distal end portion 9a and the engagement stepped portion 8a is increased and the engagement force is strengthened. If such an elastic bending phenomenon of the first leaf spring 9 by the eccentric cam 12a occurs immediately before the printing operation in which the second leaf spring 10 is held in the disengaged position by the electromagnetic solenoid 14, the printing This appears as time variations such as a delay in the start of the striking action of the hammer 8 and therefore the start of the printing operation, which is inconvenient for high-speed printing operations. However, the thickness of the first leaf spring 9 in this printer with the above-mentioned configuration is determined so that it does not easily bend due to its elastic flexibility when pressed by the eccentric cam 12a. Always eccentric cam 12a
The printing hammer 8 can be disengaged from the engaging stepped portion 8a at a certain rotational position, and therefore, the printing operation is always performed with a certain time relationship with respect to the printing command. It becomes possible to speed up the operation.
It goes without saying that the present invention is not limited to a line printer in which the drive of two print hammers is controlled by one electromagnetic solenoid as described above.

As described above, the present invention includes a print hammer to which a biasing force is applied to move the print hammer to a printing position, and each free end of the print hammer is engageable, and both have the function of holding the print hammer in a rest position. two leaf springs; a first cam for alternately disengaging each free end of the two leaf springs from the print hammer; and actuation by a printing command synchronized with the operation of the cam. an electromagnetic solenoid for maintaining the print hammer and one of the two leaf springs in a disengaged state at least until the cam disengages the other leaf spring; and the cam and the electromagnetic solenoid. In a printer comprising a second cam for forcibly returning the print hammer, which has moved to the printing position after the engagement of both of the two leaf springs has been released, to the rest position, the electromagnetic one of the two leaf springs is By making the thickness of the plate that is not held by the solenoid thicker than that of the other plate, it is possible to prevent time variations in the disengagement operation of the leaf spring from the print hammer, and to ensure that the time required for printing commands is always constant. It is therefore possible to provide a printer which can carry out printing operations in relation to each other and thus becomes suitable for high-speed printing.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view of a line printer according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view thereof. In the drawing, 2 is a type drum, 3 is a type, 5 is a leaf spring, 7 is a printing paper, 8 is a print hammer, 9 is a first leaf spring, 10 is a second leaf spring, 12 is a first cam group , 13 is a second cam group, 14 is an electromagnetic solenoid, 15 is an electromagnetic coil, and 16 is a solenoid core.

Claims (1)

[Claims] 1 a print hammer to which a biasing force is applied to move the print hammer to the printing position; two leaf springs each having a free end engageable with the print hammer and both having the function of holding the print hammer in a rest position; a first cam for mutually disengaging each free end of the two leaf springs from the print hammer; an electromagnetic solenoid for maintaining the state of disengagement with one of the leaf springs at least until the cam disengages the other leaf spring; A printer comprising a second cam for forcibly returning a print hammer that has been disengaged and moved to a printing position to a rest position, which plate of the two leaf springs is not held by the electromagnetic solenoid. A printer characterized by being thicker than the other printer.