JPH0330509B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing method for a cross-hammer type dot printer that prints while moving a print head in a direction perpendicular to the feeding direction of a recording medium.

In dot matrix printers, the following methods have conventionally been used to increase the resolution of printed characters, etc. Generally, a method is used in which printing elements such as printing wires or printing electrodes are arranged in two staggered rows. However, with this method, the configuration becomes complicated, the number of parts increases,
This results in various drawbacks such as an increase in the size of the print head and an increase in manufacturing costs. Therefore, a method has been proposed in which high-resolution printing is performed using the conventional single vertical column of printing elements. This method involves relatively moving the recording medium or print head by half a pitch in the column (vertical) direction to form dots also at intermediate positions.
However, with this method, it is difficult to relatively move the recording medium or print head exactly by half a pitch in the column direction, and because this relative movement is added during the printing operation, the printing speed cannot actually be increased. There was a drawback that caused a significant decrease in

Therefore, in the present invention, a plurality of protrusions extending parallel to the axial direction of the rotary drum are provided on the outer peripheral surface of the rotary drum. A cross-hammer type dot printer is provided with a printing hammer that substantially intersects with the protrusions of the printer, and forms characters, etc. on the recording medium by selectively driving the printing hammer and colliding with the protrusions. The present invention aims to provide a printing method suitable for high-resolution printing.

In the printing method according to the present invention, when one line of printing is formed with high resolution by N head spacings, the drive timing of the print hammer is relatively shifted by 1/N period for each head spacing. The printing medium is characterized in that the recording medium is not fed during printing of one line performed by the N times of head spacing.

An example will be explained.

In FIG. 1, side plates 1 and 2 are fixedly installed in parallel with a predetermined interval, and a rotating shaft 4 to which a rotating drum 3 is fixed is rotatably supported by both side plates 1 and 2. There is. The printing head 5 facing the rotating drum 3 is mounted on a carriage 6, and the carriage 6 is slid by two guide shafts 7 (see Fig. 2) fixed between the side plates 1 and 2. Supported for free movement. The drive motor 8 is attached to the side plate 2
The rotation of this motor 8 is decelerated and transmitted to a gear 12 via a motor pinion 9, a gear 10, and a pinion 11 integrated therewith, and the gear 12 is connected from the side plate 2 to the right. The rotary drum 3 is fixed to the end of the rotating shaft 4 that protrudes from the rotary drum 3, thereby rotating the rotary drum 3. Furthermore, gear 12
The rotation of is transmitted from a pinion 13 integral therewith to a gear 16 via a gear 14 and its pinion 15. The gear 16 is integrally provided with a clutch disk 17 on its right side, and this clutch disk 17 faces a clutch disk 19 that is integrally provided on the left side of the gear 18. The gear 16 is rotatably supported by a tube 20 fixed to the right side of the side plate 2, and a shaft 22 of a plunger 21 passes through a hollow hole in the tube 20. The gear 18 is rotatably fitted to the shaft 22, but is relatively immovable in the axial direction. The shaft 22 is urged to move backward to the left by a return spring (not shown), whereby the clutch disks 17 and 19 are meshed and connected to each other. Then, as the shaft 22 moves forward to the right by energizing the plunger 21, the meshing connection between the clutch disks 17 and 19 is severed. Further, the gear 18 meshes with a gear 23, and a winding drum 26 is integrally formed with the gear 23.
One end of the cable 25 is fastened and wound around. The cable 25 extends to the left via a pulley 26 and is connected to the carriage 6 at the other end. Therefore, the cable 25 is connected to the winding drum 24.
By winding it up, the carriage 6 and print head 5 are spaced to the right. Further, the carriage 6 is given a return force to the left by a return spring 27, and the clutch disk 17,
When the engagement of 19 is released, the carriage 6 can be returned to the home position by the spring force of the return spring 27.

As clearly shown in FIG. 2, the rotating drum 3 is
A plurality of protrusions 28 projecting integrally from the outer peripheral surface are provided at equal intervals, and these protrusions 28 extend in the axial direction of the rotating drum 3. On the other hand, in the print head 5, as shown in FIGS. 2 and 3, a plate-shaped printing hammer 29 is arranged so as to face the protrusion 28 at an angle inclined at a certain angle, and is supported by a biased leaf spring. 3
The lower end of the printing hammer 29 is clamped and held in a split groove 32 of a movable yoke 31 fixed to the free end of the printing hammer 29. A tongue-shaped portion 33 extending to both sides of the biased leaf spring 30 is integrally formed from the base (lower end portion) of the biased leaf spring 30, and both tongue-like portions 33 and the base portion are connected to the support plate via a pin 34. It is fixed to the back of 35. A front yoke 37 is fixed to the back surface of the biasing leaf spring 30 via a spacer plate 36 and a pin 34 . The front yoke 37 is formed into a substantially circular shape, and has a center hole 38 in the center thereof, through which the rear part of the movable yoke 31 is inserted. A donut disk-shaped permanent magnet 39 is fixed to the back surface of the front yoke 37, and a cylindrical cap-shaped rear yoke 40 is further fixed to the back surface of the permanent magnet 39. A center yoke 41 is fixed to the center of the bottom of the rear yoke 30 facing forward, and a permanent magnet 39 is attached to the center yoke 41 .
The movable yoke 31 moves to the center yoke 41 due to the magnetic flux of
is magnetically attracted to the front end surface of the spring 30, thereby causing the biasing leaf spring 30 to bias backward against its own spring force. Therefore, the printing hammer 29 is also held in a position retracted from the protrusion 28 of the rotating drum 3. A release coil 42 is wound around the center yoke 41, and by energizing the release coil 42, the magnetic flux of the permanent magnet 39 can be canceled out. Since the magnetic attraction to the center yoke 41 of
It moves forward due to the spring force of and collides with the protrusion 28 of the rotating drum 3. As shown in FIG. 2, a recording medium 43 and an ink ribbon 44 are inserted between the protrusion 28 of the rotating drum 3 and the printing hammer 29.
Due to the collision between the protrusion 28 and the printing hammer 29, a dot is formed on the recording medium 43 at the collision (intersection) position. Further, the support plate 35 has a horizontal plate portion 45 formed integrally therewith, and this horizontal plate portion 45
is fixed onto the carriage 6 via screws 46.

The protrusion 28 and the printing hammer 29 intersect as shown in FIG. 4, and this intersecting position is shifted as follows. The protrusions 28 can face the printing hammers 29 one after another as the rotating drum 3 rotates, and each protrusion 2
8 changes the intersection position with respect to the printing hammer 29 in the column (vertical) direction of the dot matrix. At the same time, the printing hammer 29 changes its crossing position with respect to the projection 28 in the row (horizontal) direction of the dot matrix depending on the spacing of the printing head 5 (carriage 6). One protrusion 28 is a printing hammer 29.
By selectively driving the print hammer 29 while passing in front of the print head 5, a row of dot matrix is formed, and by repeating this while the print head 5 is moving, a predetermined dot matrix is formed. Dot matrix characters, figures, etc. are formed on the recording medium 43. Since the print hammer 29 is inclined at a predetermined angle, even if the rotation of the rotary drum 3 and the spacing of the print head 5 are performed simultaneously and continuously, the row of dot matrix are arranged in one vertical column.

The position of the protrusion 28 facing the printing hammer 29 can be detected by a dot sensor 48 shown in the first figure. The dot sensor 48 includes a light emitting element and a light receiving element (both not shown) therein.
The outer periphery of the detection disk 49, which is integral with the motor pinion 9, is inserted into the recess of the dot sensor 48, and a large number of small holes (not shown) are arranged in a circle on the outer periphery. A home sensor 51 provided relatively close to the side plate 1 is similar to the dot sensor 48, and when the carriage 6 is in the home position, it is integrally connected to one of the lower legs 52 and 53 of the carriage 6. The extending shielding plate 54 enters into the recessed portion of the home sensor 51. Further, in FIG. 1, a buffer member 55 made of elastic rubber or the like is fixed to the left end of the guide shaft 7, and this buffer member 55 determines the home position of the carriage 6, and the carriage 6 is moved by the return spring. The spring force of 27 cushions and absorbs the impact when returning to the home position.

Next, the printing method of the present invention applied to the cross hammer type dot printer having the above configuration will be explained.

Before I explain the details, let me give you a general explanation:
It is possible to switch between printing in high resolution mode and printing in normal mode. In the high resolution mode, in this embodiment, one line of printing is formed through two head spacings as shown in Figure 5. In Figure 5, ○ is the dot formed by the first head spacing, and ●
is the dot formed by the second head spacing. When printing in normal mode,
Almost the same as before, one head spacing
A line print is formed as shown in the sixth figure. Printing in this normal mode is performed using the high resolution mode 1.
This is the same as the print formed by the second head spacing.

In FIG. 7, 56 is a control unit of the central processing unit CPU, which receives signals from the dot sensor 48 and the home sensor 51, and controls the print head 5, motor 8,
The clutch solenoid plunger 21, paper feed device 57, print data buffer 58, shift register 59, and driver 60 are controlled according to the flow chart shown in FIG. _L1 is a means for determining whether the spacing of the print head is the first or second time when printing in the high resolution mode, and is constituted by, for example, a flip-flop.

The print data for the print line is stored in the buffer 58, and _L1 is cleared to 0. Also, the clutch solenoid 21 is energized, thereby disengaging the clutch disks 17 and 19 of FIG. If the carriage 6 (print head 5) is in the home position, there will be no movement, but if it is not,
The carriage 6 is returned to the home position by the force of the spring 27. The motor 8 is then driven, and then the clutch solenoid 21 is de-energized.
The clutch disks 17 and 19 are engaged, and the motor 8
The rotation of gears 9 to 16, clutch disk 17,
19, the signal is transmitted to gears 18 and 23, and gear 24, which is integrated with gear 23, rotates. By winding the cable 25 around the drum 24, the carriage 6 moves to the right. At this time, the dot sensor 48 generates the detection pulse shown in FIG. 8A by the rotation of the detection disk 49. However, this detection pulse is not immediately used as a timing pulse for the print head 5. FIG. 8A shows only the number necessary to print one column of the dot matrix, and the protrusions 28 shown in FIG. 2 or 4 are shown in the 1st, 2nd, . It is set to generate a pulse when the position is reached. By the way, there is a limit to the response period of the printing hammer 9, and the period _t1 of the detection pulse is shorter than the limit period.
Therefore, the printing hammer 9 cannot follow the detection pulse of period _t1 . Therefore, when printing in high resolution mode, depending on whether the output of _L1 is "0" or "1",
The control unit 56 converts it into two types of print timing signals shown in FIG. 8B or C. The pulses of the print timing signal in FIG. 8B correspond to the odd numbered pulses of the detection pulses, and the pulses of the print timing signal of FIG. 8C correspond to the even numbered pulses of the detection pulses. The pulses between these two types of printing timing signals are out of phase with each other by half a cycle, and both of their periods t ₂ correspond to twice the period t ₁ , and the printing hammer 29 can sufficiently follow them.

Since the output of _L1 is "0" during the first head spacing, the control unit 56 generates the print timing signal shown in FIG. 8B, and in synchronization with this, the print hammer 29 of the print head 5 is driven. be done. Therefore, as shown in FIG. 5, dots 0 are selectively formed in odd-numbered rows. When the first printing of one line is completed, _L1 is set to "1". Also the first
In the figure, the motor 8 is de-energized and the clutch solenoid 21 is energized. As a result, the clutch disks 17 and 19 are disengaged, and the carriage 6 is returned to the home position by the spring force of the return spring 27. When the carriage 6 returns to the home position, the motor 8 is driven and the clutch solenoid 21 is de-energized. As a result, the clutch disks 17 and 19 are engaged and the carriage 6 begins the second spacing in the same manner as described above. During this second spacing, since the output of _L1 is "1" in FIG. 7, the control unit 56 generates the print timing signal C in FIG. 8, and in synchronization with this, the print hammer 29
is driven. Since the pulse of the print timing signal during the second spacing is shifted by half a cycle from that during the first spacing, the dot ● formed the second time is located in the middle of the dot ○ formed the first time.
In other words, they are formed in even numbered rows (FIG. 5). When the second printing of one line is completed, _L1 is cleared to "0" again, and the power supply to the motor 8 is stopped.
The clutch solenoid 21 is energized and the carriage 6 is returned to the home position. And the carriage 6
During the return, the paper feeding device 57 shown in FIG. 7 is driven, and the recording medium 43 shown in FIG. 2 is line-feeded by a predetermined amount.

When printing in the normal mode, one line is printed by one head spacing, but _L1 is always kept cleared to "0". Therefore, in the normal mode, the control section 56 in FIG. 7 always generates the printing timing signal shown in FIG. 8B, and the printing hammer 29 is driven in synchronization with this. Therefore, the characters formed in the normal mode are formed as shown in FIG. 6, which are the same as the characters printed during the first spacing in the high resolution mode.

Note that the configuration for obtaining the detection pulse shown in FIG. 8A is not limited to the above embodiment. Furthermore, the print head 5 is driven by the print timing signal shown in FIG. 8C during the first head spacing, and the print head 5 is driven by the print timing signal shown in FIG. 8B during the second head spacing. You may.

Furthermore, in the above embodiment, when in high resolution mode,
Although this is an example in which 11 lines of printing are performed using two head spacings, the present invention is not limited to this. At this time, for example, when one line of high-resolution printing is performed by N times of head spacing, the print timing signal for each head spacing is relatively shifted by 1/N period.

As described above, according to the present invention, high-resolution printing can be performed using multiple head spacings by simply shifting the printing timing phase during each head spacing, and during that time the print head and recording medium are connected. Since there is no relative movement in the column direction, there is no need to complicate the printer configuration.
Desired printing can be performed at high speed and accurately. Furthermore, low resolution printing in normal mode can be selected as needed.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a plan view of a cross-hammer type dot printer, FIG. 2 is an enlarged sectional view taken along the line of FIG. 1, FIG. 3 is an enlarged front view of the printing head, and FIG. FIG. 5 is an enlarged view showing an example of printing in high resolution mode; FIG. 6 is an enlarged view showing an example of printing in normal mode. FIG. 7 is a circuit block diagram, FIG. 8A is a time chart showing the detection signal of the dot sensor, and FIG.
Figure B is a time chart showing the print timing signal during the first head spacing in high resolution mode or normal mode, and Figure 8C shows the print timing signal during the second head spacing in high resolution mode. Time Chart FIG. 9 is a flowchart for the printing method of the present invention. 3...Rotating drum, 5...Print head, 28...
...Protrusion, 29...Printing hammer.

Claims (1)

[Scope of Claims] 1. A print head is provided with a plurality of protrusions extending in the axial direction on the outer peripheral surface of a rotating drum, and is spaced in front of the rotating drum in a direction perpendicular to the feeding direction of the recording medium. A cross hammer type dot printer is provided with a printing hammer that faces the projection substantially crosswise, and the printing hammer is selectively driven to form a dot by collision between the projection and the printing hammer, comprising: 1 The line is printed by spacing the print head N times, and the hammer is driven by a print timing signal whose phase is relatively shifted by 1/N period for each head spacing, During head spacing, while the rotating drum is continuously rotated and the recording medium is kept stationary, the dots formed by the second and subsequent head spacings are inserted between the dots formed by the first head spacing. A printing method of a cross hammer type dot printer that is characterized by filling in the dots with 2. A plurality of protrusions extending in the axial direction are provided on the outer circumferential surface of the rotating drum, and a print head spaced in front of the rotating drum in a direction perpendicular to the feeding direction of the recording medium is provided with a plurality of protrusions substantially parallel to the protrusions. A cross hammer type dot printer is provided with printing hammers that face each other in a crosswise manner, and forms dots by selectively driving the printing hammers and colliding with the projections and the printing hammers. Printing by mode can be selected, and in high resolution mode, one line is printed by N times spacing of the print head,
The hammer is driven by a printing timing signal whose phase is relatively shifted by 1/N period for each head spacing, and the rotary drum is continuously rotated during the N head spacings, and While the recording medium remains stationary, the spaces between the dots formed by the first head spacing are filled with the dots formed by the second and subsequent head spacing. In normal mode, one head spacing is performed. A printing method for a cross hammer type dot printer, characterized in that one line is printed by spacing, and the printing hammer is driven by a printing timing signal of the same phase for each head spacing.