JPH0351226B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hammer drive control method for an impact printer, and in particular to a hammer drive control method for an impact printer, in particular a method for controlling the hammer drive of an impact printer in a state in which a hammer provided for each printing digit is wound up against the biasing force of a biasing spring. The desired digit is printed by releasing the latch at the desired printing timing, and the hammer is simultaneously hoisted up by a retraction cam for each printing cycle, and the hammer is held by multiple adjacent The present invention relates to an improved hammer drive control method for an impact printer using electromagnetic means commonly provided for a group of hammers.

[Prior Art] Various printers are well known as output devices for information processing devices or calculators, etc., but printers of a type in which a hammer is driven at a desired printing timing toward a type drum having a plurality of type characters formed on its outer periphery are well known. An impact printer is suitable as a small portable printer, and can perform clear printing using an ink ribbon or an ink roll.

Normally, the printing drum is stamped by the hammer using a biasing spring, and after each printing cycle is completed, the hammer is released from the type drum and wound up to the latched position against the biasing force of the biasing spring. action takes place.

Further, in this type of impact printer, an electromagnetic means is provided to hold the hammer in a wound state, and the hammer is latched by an armature of the electromagnetic means. It is preferred that the hammers are provided with electromagnetic means in common. In order to select a hammer for a desired printing operation from a plurality of hammer groups, a reset cam that rotates in conjunction with the type drum and includes a cam with a different phase for each corresponding hammer is used as a digit selection means. .

However, in this type of impact printer, the reset cam and the hammer repeatedly come into contact during each printing cycle, causing various problems such as wear and noise caused by this contact, and increased power consumption due to contact resistance. However, there were various problems such as the durability of the printer decreased and the need for a noise cover increased the size of the device.

Japanese Patent Application Laid-Open No. 57-128575 as an improved conventional device
According to this device, a shallow latch part is provided between each hammer and the armature of the electromagnetic means to provide a normal printing standby state, and a deep latch part to retract the hammer to a position where it does not come into contact with the reset cam. This allows the hammer, which is not used for printing, to be evacuated from the reset cam.

Therefore, this improved conventional method has the effect of eliminating unnecessary wear and noise generation, and reducing power consumption.

[Problems to be Solved by the Invention] Disadvantages of the Prior Art However, according to the conventional method, during printing, all the hammers corresponding to one electromagnetic means are held in a deep latched state with the armature, and then suddenly these hammers are There was a problem in that the hammer had to be pulled out of the engaged state.

That is, the first one of a set of three-digit hammers
Even when a digit is to be printed, all three digit hammers are held in a latched position deeper than the armature, ie, leaning against the armature. Therefore, in this holding state, the load applied to the armature becomes large, and in order to remove the armature from this state, the power required to resist the load of the first digit hammer, which performs the printing function, is required. , it is necessary to supply a large amount of power to withstand the load of three orders of magnitude for a hammer. As a result, there are disadvantages in that power consumption increases unnecessarily and excessive heat generation occurs.

Further, in this conventional method, the armature is suddenly pulled while the hammer is still leaning against the armature, which causes severe wear on the latch portion of the hammer, which has a negative effect on durability.

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to reduce the load applied to the armature during printing, and to detach the armature from the hammer with the minimum necessary power supplied to the electromagnetic means. An object of the present invention is to provide an improved hammer drive control method for an impact printer, which is capable of suppressing wear of the latch portion of the hammer and armature.

[Means and operations for solving the problems] In order to achieve the above object, the present invention forms a shallow latch that forms a printing standby state and a non-printing retracted state between the hammer and the armature as in the conventional art. In the actual printing state, the printing preparation process and stamping process are separated while ensuring both positions with the deep latch, and in the printing preparation process, the hammer group used for printing at least in the corresponding printing cycle is moved from the deep latch to the shallow latch. At the time of this switching, the retraction cam causes the hammer to overstroke from the deep latching position, and by energizing the electromagnetic means, the hammer can be disengaged in a state where the armature is not engaged with the hammer. This eliminates unnecessary friction loss.

Also, in the stamping process, the timing between the reset cam and the hammer is adjusted, and the reset cam lifts the hammer that requires printing, and with the shallow latch released, excitation current is supplied to the electromagnetic means to create a connection between the hammer and the armature. This eliminates unnecessary friction losses.

Therefore, since both of the latches are released with the armature and the hammer not engaged, it is possible to release the latch as desired with very little energy input to the electromagnetic means. Furthermore, since there is less wear on the hammer and armature, durability can be improved.

Furthermore, according to the present invention, the printing preparation step is not performed in a non-printing continuous paper feeding state, so the reset cam and hammer do not come into contact with each other during paper feeding, thereby reducing power loss in the main drive source and noise generation. can be removed reliably, and there is less wear between the reset cam and hammer, resulting in excellent durability. .

[Embodiments] Preferred embodiments of the present invention will be described below based on the drawings.

1 and 2 show a preferred embodiment of an impact printer to which the hammer drive control method according to the present invention is applied, and in the illustrated impact printer, the hammer is released from the printing standby state based on a printing command. One electromagnetic means for each three-digit hammer group
This figure shows a 3-digit, 1-electromagnetic means type printer. Of course, in the present invention, the number of hammer digits each such electromagnetic means is responsible for is arbitrarily selected, thereby reducing the number of electromagnetic means, which have a relatively large volume, and making the device compact and portable. be able to.

The type drum 10 is continuously rotated at a substantially constant speed during printing or paper feeding by a drive motor (not shown), and a plurality of type characters formed on its outer periphery pass through a printing position in a predetermined order. The type arrangement in this embodiment is divided into groups of three digits corresponding to the hammers, which will be described later, which are divided into groups of three, and within each group, a predetermined pitch type is offset in the direction of rotation.

A plurality of hammers 12 are arranged in alignment facing the printing position of the type drum 1.
A recording paper 14 and an ink ribbon 16 are inserted between the printer 0 and the hammer 12. Each hammer 12 is connected to the type drum 10 by a respective biasing spring 18.
When a desired selected hammer 12 flies toward the printing drum 10 by the urging force of the urging spring 18, the type at the printing position at that time is printed on the recording paper 14. Ru.

The rotation of the type drum 10 is transmitted to the type detection disk 28 by a transmission wheel train consisting of a gear 20, a pinion, a gear 24, and a pinion 26, and the type detection disk 28 and an electromagnetic detector disposed adjacent thereto. 30, the position of the type on the type drum 10 can be constantly detected as a character pulse.

Of course, such a character pulse detector can detect not only the position of the type but also the reset pulse at the start position of the type drum 10, and a plurality of the detection disks 28 can be provided as necessary. suitable.

In the present invention, a reset cam 32 and a retraction cam 34 are provided to move the hammer group 12 away from the type drum 10 against the biasing springs 18 and into a printing standby state.

In the embodiment, the reset cam 32 is connected to the shaft of a pinio 26 which transmits the rotational driving force of the type drum 10 in order to rotate in synchronization with the type drum 10 and control the printing timing of the corresponding hammer groups 12, respectively. The reset cam 32 has a reset portion on its outer periphery, and when the reset portion comes into contact with the hammer 12, the hammer 12 is moved against the biasing spring 18 to a printing standby state away from the type drum 10. In the embodiment, the reset cam 32 is provided with three reset portions 32a along its circumferential direction, and the reset shoulder portion 12a of the hammer 12 that has fallen into the depressed portion 32b of the reset cam 32 during printing can be reset to one of the three reset portions 32a. The printer can be pushed up and reset to the printing standby state by the reset portion 32a.

A retaining arm 12b is provided at one end of the hammer 12, and the retaining arm 12b engages with a retaining member to maintain the print-ready state of the hammer 12, and in the embodiment, the retaining member is connected to the armature 38 of the electromagnetic means 36.
It is formed from. The armature 38 is constantly biased clockwise in FIG.
b. In the embodiment, the armature 38 includes three digits of hammers 12 adjacent to each other.
engage at the same time. Therefore, it is possible to select which hammer 12 is used for printing by both the armature 38 and the reset cam 32. An electromagnetic means 36 is provided to release the print standby state of the hammer 12, that is, a restrained state of the hammer 12 by the armature 38. In the embodiment, the electromagnetic means 36 is composed of an electromagnetic solenoid, and the electromagnetic solenoid is activated by a printing command. As a result, the armature 38 is attracted counterclockwise in FIG. 2, and the three-digit group of hammers 12 are released from being restrained. Only the hammers 12 in the digit are driven toward the type drum 10 to make a mark, making it possible to perform the desired printing action.

As mentioned above, in order to wind up each hammer 12 against the biasing force of the biasing spring 18 and take a retracted state further away from the print standby state, the retract cam 34 is provided, and in this retracted state, the hammer 12 is A printer that is rotated against the biasing spring 18 to a position where it does not come into contact with the reset cam 32, completely eliminating collision and contact between the hammer 12 and the reset cam 32, eliminating wear and noise, and reducing power consumption. can be obtained.

The retracting cam 34 simultaneously rotates all the hammers 12 to the retracted state, and this retracting action is performed for each printing cycle.
The retracted position of each hammer 12 includes not only a position in which the armature and the hammer are latched at each latched position, but also a position in which the armature and the hammer are rotated further from the latched position and overstroked.

The shaft 42 of the retraction cam 34 carries at one end a clearing lever 44 which has a roller 48 in contact with an actuating cam 46 fixed to one end of the type drum 10, so that the type The operating cam 46 rotates the retracting cam 34 via the clear lever 44 every rotation of the drum 10, that is, each printing cycle, and the above-described retracting action is performed for each printing cycle in the printing pause state.

The actuating cam 46 has cam surfaces 46a and 46b of different heights on its outer periphery, each forming a cam surface that overstrokes the retraction cam 34 and maintains the hammer 12 in a shallow latched position as described below.

In the present invention, in order to maintain both the printing standby state and the retracted state of the hammer 12, the hammer 12 is
and the armature 38 are formed with a shallow latch portion that holds the hammer 12 in the printing standby position and a deep latch portion that holds the hammer 12 in the retracted position. It is formed from latch portions L1 and L2 provided on the holding arm 12b of. The shallow latch L1 engages the armature 38 to restrain the strike of the hammer 12, and in this latched state the reset cam 32 contacts the shoulder 12a of the hammer 12. In other words, the reset cam 32 is connected to the shoulder 1 of the hammer 12.
Push up 2a and attach latch L1 to armature 38.
can be engaged with.

On the other hand, the deep latch L2 can completely disengage the shoulder portion 12a of the hammer 12 from the reset cam 32 through engagement with the armature 38, thereby improving durability by eliminating power loss, noise removal, and wear. Beneficial.

In the embodiment, a reset pulse detector is provided to take out the reference signal of each printing cycle and the reset cam signal as a reset signal, and the reset signal is taken out using the swinging action of the clear lever 44, and this reset pulse detector is provided. Based on the signals, paper feeding and other auxiliary operations are controlled, and the printer prepares for printing the next line.

The reset pulse generator is formed of a reset pulse switch including two contacts 54 and 56, one end of which is fixed with an insulating substrate 52 in between.
4 and 56 have a biasing force in the direction of bringing them into close contact with each other. A switch operator 58 made of a wire spring held by the clear lever 44 is engaged with one contact 54, and the contact state of both contacts 54 and 56 is determined according to the swinging position of the clear lever 44. control.

As is clear from FIG. 3, the switch operator 5
8 is held on the clear lever 44 by a stop pin 60, and its position is regulated by stopper pins 62 and 64. And both the contacts 54, 5
6 is also positionally regulated by stopper pins 66 and 68, respectively.

Figure 3 shows the normal state, with the clear lever 44
is moved by the spring 70 to the stopper 72 (first
As a result, the switch operator 58 pushes up the contact 54 until it contacts the stopper pin 66, and at this time, the other contact 56 is restricted by the stopper pin 68. Therefore, both contacts 54 and 56 are in an open state.

On the other hand, when the printing cycle is completed, the clear lever 44 is rotated clockwise by the operating cam 46, as described above. Therefore, as shown in FIG. 4, the switch operator 58 is separated from the contact 54, and by contacting both contacts 54 and 56, a reset pulse can be output.

As described above, according to this embodiment, the reset pulse can be extracted using the essential mechanical rocking motion of the clear lever 44 in each printing cycle.

In the embodiment, after each line has been printed on the recording paper 14, the recording paper 16 is driven to be fed by a feed roller and a guide roller 76. In the paper feed in this embodiment, the motive force of the drive motor is stored in the feed spring during the printing operation, and after each line of printing is completed, this stored force is released in a short time to feed the paper to the feed roller 7.
It consists of a structure that rotates 4 rapidly.

A governor mechanism for storing and discharging the feed spring, controlling the speed of the feed roller 74 at this time, and preventing bouncing due to large inertia at the end of the feed is shown in FIGS. 5 and 6.

A feed gear 80, which is formed by integrally molding sector gears 80a and 80b with two different diameters, is rotatably supported on the feed shaft 78 of the feed roller 74. Therefore, this feed gear 80 can rotate separately from the feed roller 74. A ratchet wheel 82 is firmly fixed to the tip of the roller shaft 78.

A cylindrical spring support part 84 is fixed to the small diameter sector gear 80a loosely fitted to the roller shaft 78, and a coil spring 86 used as a feed spring is attached to this spring support part 84. One end of the spring 86 is locked to a pin 88 set on the sector gear 80a, and the other end is locked to the feed gear 80.
It is locked to a stopper 90 that stops the rotation. A winding gear 92, which is a partially toothed gear that meshes with the sector gear 80a, is fixed to the tip of a shaft 94 of the type drum 10.
2 can wind up the small-diameter sector gear 80a and store a sending force in the sending spring 86.

As shown in FIGS. 7 and 8, the drum shaft 9
A pinion 98, which is integrally fixed to the flywheel case 96, is press-fitted into the small diameter portion of the tip of 4, and this pinion 98 is connected to the large diameter sector gear 8.
It meshes with 0b. A flywheel 100 is rotatably fitted loosely into the small-diameter tip of the drum shaft 94 protruding into the flywheel case 96, and the flywheel 100 also has a leaf spring 102 that is fixed at both ends to the flywheel case 96. is pressed against the inner surface of the open end side of the flywheel case 96. Therefore, a desired frictional slip is obtained between the flywheel case 96 and the flywheel 100, which rotate together with the pinion 98, so that the feed roller 74 drives the recording paper 14 by one line. Feed roller 74 when
The energy generated during a sudden stop can be absorbed by the rotation of the flywheel 100, thereby reliably eliminating the bounce of the feed roller 74.

As shown in FIG. 6, a feed pawl 104 is rotatably supported on a shaft 106 on the side surface of the large-diameter sector gear 80b.
4 is always pressed toward the pawl portion of the pawl wheel 82 mentioned above. A positioning spring 110 fixed to a substrate (not shown) is resiliently engaged with the claw portion of the ratchet wheel 82, and the feeding position of the ratchet wheel 82 is stabilized.

As described above, the paper feeding mechanism in the embodiment is provided with a feeding force storage and release mechanism, and a governor mechanism that controls the speed and prevents bouncing during feeding operation.
FIG. 5 shows a state in which the sector gear 80a comes into contact with the stopper 90 and is stopped. In this state, the winding gear 92 and the sector gear 82a can rotate freely without meshing with each other.

When the type drum 10 performs a printing operation and rotates from the state shown in FIG. 5, the winding gear 92 winds up the sector gear 80a in the direction of the arrow, and due to this winding action, a biasing force is stored in the reverse spring 86. The position of the feed pawl 82 is held by a positioning spring 110.

The winding gear 92 winds up the sector gear 80a,
After printing on the type drum 10 is completed, the toothless portion of the winding gear 92 comes to face the sector gear 80a, thereby breaking the meshing state between the two, and the biasing force of the feed spring 86 causes the feed gear 80 to Both sector gears 80a and 80b quickly return to rotate in the opposite direction to the arrow. The rotational speed at this time is controlled by the governor train including the flywheel 100 through the meshing of the large-diameter sector gear 80b and the pinion 98, and is maintained at a predetermined suppressed speed. Therefore, the feed roller 74 correctly feeds the recording paper 14 at the optimum feed speed without causing slips or the like.
can be driven by one line.

This feeding drive is performed by the meshing of the feed pawl 104 provided on the foot surface of the feed gear 80 and the ratchet wheel 82.

When the feed gear 80 rotates to the state shown in FIG. 5, the end surface of the feed gear 80 touches the stopper 90.
collides with and tries to cause a bouncing phenomenon. However, in this embodiment, during this bound reversal, only the pinion 98 of the governor gear train and the flywheel case 96 rotate in reverse together with the feed gear 80, and the other gear train, that is, the flywheel 100, The normal rotation in the feeding direction continues due to the friction slip. Therefore, even when the feed gear 80 is rapidly stopped or reversed, no excessive load beyond friction slip is applied to the cabana gear train, and the gear train will not be damaged. The slip force of the friction slip mechanism acts to suppress the bounce of the feed gear 80, and the bounce of the feed gear 80 is quickly absorbed by a small amount, allowing the feed gear 80 to return to the correct stop position shown in FIG.

The above-mentioned force for suppressing the reverse bounce is proportional to the inertial energy stored in the rear stage of the cabana gear train from the friction slip mechanism, that is, in the flywheel 100.
By increasing the speed increase rate of the cabana gear train or increasing the mass of the flywheel 100, the inertia energy can be set larger than the reverse bound energy of the feed gear 80, and a good bounce suppressing effect can be obtained.

Therefore, according to this embodiment, the recording paper 14 can be accurately fed by a predetermined amount in a short time, and the printing speed can be increased.

The impact printer used in the present invention has the above configuration, and the print control function of the present invention will be explained below.

FIG. 9 shows a timing chart when printing one line "1002100100.0" in red. The type drum 10 in this embodiment has a 12-digit type arrangement, as shown in the pair 10 diagram, and has a ``0''
to ".", and each printed character is arranged in a different phase corresponding to each of the three hammers 12 as described above. Therefore, the character pulse detector 30 detects "1". ” to “42” are detected.

As is clear from FIG. 9, one printing cycle includes a stamping process used for actual printing and printing preparation processes before and after.

When printing starts at time _t1 , when the power is turned on, current is supplied from the control circuit to the drive motor, and the type drum 10 and each cam linked thereto start rotating. At the same time, a printing command is supplied, but this command is once stored in a register, and after each character pulse and other timings are taken, excitation current is supplied to the four electromagnetic means 36 in the embodiment at respective timings. becomes. In the initial state at time _t1 , the reset pulse detector described above outputs a reset pulse of "1", thereby maintaining the control circuit (not shown) in its initial state.

A characteristic feature of the present invention is that, in the initial stage of this printing preparation state, each hammer 12 is set to the deep latch L.
As shown in FIG. 11, at time t ₁
, the operating cam 46 interlocked with the type drum 10 has a high cam surface 46a that is connected to the clear lever 44.
As a result, the retraction cam 34 connected to the clear lever 44 is driven to the most clockwise position in the figure, moving the hammer 12 further clockwise than its deep latch L2. Hold it in the overstroke position.
Therefore, in FIG. 11, the armature 38 of the electromagnetic means 36 is separated from the hammer 12 and can be moved very easily as shown by the chain line without being subjected to the biasing force of the hammer 12.

At time t ₂ and t ₃ , a preliminary excitation action is performed on the solenoid of each electromagnetic means 36 in preparation for printing, thereby causing the armature 38 to
The hammer 12 is moved from the solid line position to the chain line position in the figure.

Since the movement of the armature 38 at this time is not subjected to any urging force from the hammer 12, a no-load suction operation is performed, and an extremely quick and reliable evacuation movement is performed with little power consumption and without fear of wear or other problems. I can do it.

In the embodiment, the preliminary energization of each electromagnetic means 36 is divided into two periods at times t ₂ and t ₃ in order to prevent large current consumption from occurring at the same time, and by shifting the energization timing. Therefore, averaged power consumption can be achieved.

In the embodiment shown in FIG. 9, all four electromagnetic means 36 are pre-energized, but this is because the printing command is applied to at least one of the hammers 12 corresponding to each electromagnetic means 36. This is because the electromagnetic means contains a signal to be used for printing, and if there is no corresponding printing request for the hammer in the printing command, there is no need to preliminarily energize the electromagnetic means.

FIG. 12 shows the state immediately before the hammer 12 is latched by the shallow latch L1 at time _t4 ,
By the rotation of the operating cam 46, the clear lever 44
The roller 48 is held by the cam surface 46b, and due to this slight return action, the retraction cam 34 is
2 slightly counterclockwise to return the armature 38 from the overstroked state shown in FIG. 11 to a state in which it can be engaged with the shallow latch L1.

Then, at time _t5 , the electromagnetic means 36 is de-energized, and the armature 38 rotates back toward the hammer 12, as shown by the chain line in FIG. At this time, the engagement between the armature 38 and the hammer 12 is at a position where the hammer 12 is slightly rotated from the shallow latch L1 since the hammer 12 is held by the retraction cam 34.

At time t ₆ , the actuation cam 46 separates from the clear lever 44 , and as a result, the retraction cam 34 also separates from the hammer 12 and the hammer 12 moves its shallow latch L 1 to the armature 38 at time t ₇ as shown in FIG. is held in the engaged state. This state is a printing standby state, and the shoulder 1 of the hammer 12
2a is in a state where it can come into contact with the outer periphery of the reset cam 32, and the armature 38 and the reset cam 3
It is understood that the hammer 12 can be controlled for printing by both 2 and 2. Between times _t6 and _t7 , the clear lever 44 operates the reset pulse detector and the reset pulse becomes "0".

The printing preparation step is completed as described above, and at this time, the type drum 10 has a rotational position that has almost reached the character pulse "1" character position, and thereafter, desired characters sequentially approach the printing position.

Therefore, by comparing the character pulse and a predetermined printing command, the four electromagnetic means 36 are energized at the corresponding character position as shown in the figure based on the coincidence signal for each digit, and the desired printing is performed. effect can be obtained.

One rotation of the reset cam 32 corresponds to the pitch of three character pulses, and as shown in FIG. As a result, each hammer 12 can perform one printing operation for one rotation of the reset cam 32.

A further feature of the present invention is that when the armature 38 separates from the shallow latch L1 of the hammer 12 during this printing operation, the hammer 12 has already been rotated clockwise by a predetermined amount by the reset cam 32, and the armature 38 and the shallow latch L1 are rotated clockwise by a predetermined amount. It is extremely easy to separate from L1.

This printing condition is shown in FIG. 14, and the hammer 1
2 is rotated slightly clockwise from the state shown in FIG. 13 by the reset portion 32a of the reset cam 32, whereby the armature 38 and the shallow latch L
1, and then the armature 38 is given a rotational action toward the position indicated by the dashed line in the arrow direction by energizing a predetermined solenoid. , without any biasing force of the hammer 12 being applied.
A quick and reliable evacuation action can be performed with little power consumption and no friction loss.

As shown in FIG. 15, when the reset cam 32 rotates and its depressed portion 32b corresponds to the shoulder 12a of the hammer 12, the hammer 12 is moved counterclockwise by the biasing force of the biasing spring 18. It is rotated rapidly, thereby producing the desired printing effect. This printing timing is reset cam 3.
Since it is determined by the shape of the cam 2 and is mechanically interlocked with the type drum 10, it is possible to always obtain stable printing quality.

As described above, the printing operation for the desired selected digit is performed until time _t8 , and one line printing is completed.

At time _t8 , the motor is de-energized and the field winding of the motor is directly shot, whereby the motor is rapidly braked to a stop, and at time _t9 , just before the motor is stopped, the operating cam 46 pushes the clear lever 44 again. The printer finishes the printing operation at time _t10 while preparing to print the next line by pushing up with the cam surface 46a and outputting a reset pulse.

As described above, according to the present invention, in the normal state, the armature 38 is held in the deep latch L2 to completely cut off the contact between the hammer 12 and the reset cam 32, but in the actual printing state, the printing preparation is performed. In the process, set the armature 38 to the shallow latch L1.
The actual printing operation is performed from this shallow latch L1. In both of this preliminary energization and printing energization, the hammer 12 is moved to the retracting cam 34.
The latch is held clear of the armature, allowing armature 38 to operate quickly and stably with almost complete no-load suction and no power or friction losses.

In FIG. 9, the printing color of the ink ribbon 16 is switched from black to red in the pre-preparation process, the ink ribbon 16 is fed near the end of the printing process, and the paper feeding action described above is performed in the post-preparation process. It will be done.

As described above, a quick and reliable printing operation with low power consumption can be obtained in the actual printing process, but
Furthermore, in non-printing continuous paper feed conditions, the invention maintains the hammer 12 in a deep latched position by the armature 38, thereby causing the hammer 1
2 and the reset cam 32 are completely cut off.

FIG. 16 shows the state of each part during continuous paper feeding, and even when the motor is energized, there is no printing command for any digit, so no preliminary energization is performed to the electromagnetic means 36. Armature 38 is always deep latch L2 of hammer 12.
As a result, continuous paper can be fed smoothly without any contact between the reset cam 32 and the hammer 12 and without causing noise or friction loss.

In the above-described embodiment, the hammer used for printing in the printing preparation process and the corresponding armature are separated from each other by the retraction cam 34, and the two rotational positions of the retraction cam are activated. Although this movement is performed on the cam surfaces 46a and 46b of the cam 46 at different heights, in the embodiment, such movement of the hammer in the print preparation process is performed on the retracting cam 3.
4 and the reset cam 32. That is, in order to temporarily overstroke the hammer 12 latched at the deep latching position L2 and break the engagement between the hammer 12 and the armature 38, the retraction cam 34 is used in the same way as in the embodiment. Move hammer 12 to shallow latch position L
1, the position controlled by the cam surface 46b of the actuating cam 46 in the above embodiment can also be used by the high cam surface of the reset cam 32, and thereby,
It becomes possible to perform reliable position control of the hammer using the cam surface of the reset cam 32 that directly controls the hammer.

[Effects of the Invention] As explained above, according to the present invention, the hammers of each digit can be selectively held in both the shallow latching position and the deep latching position by electromagnetic means.
When printing is not required, the corresponding hammer can be held in a deep latched position to disengage the hammer from the reset cam, significantly reducing noise or friction loss. The armature and the hammer latch are always separated from each other using a retraction cam in a state where they are disengaged from each other, so that the electromagnetic means always performs a no-load suction action, reducing its capacity and making the device more compact. Furthermore, the reduced power consumption and reduced frictional losses can significantly reduce the maintenance costs of the equipment.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a preferred embodiment of an impact printer using the hammer drive control method according to the present invention, FIG. 2 is a schematic explanatory diagram showing the hammer drive section of FIG. 1, and FIGS. 3 and 4 is an explanatory diagram showing the action of the character pulse detector in FIG. 1, FIG. 5 is an enlarged perspective view of main parts of the paper feeding mechanism in FIG. 1, and FIG. 6 is a side view showing the governor mechanism in FIG. 5. 7 is a partially cutaway perspective view showing the flywheel portion in FIG. 6, FIG. 8 is a sectional view of the main part of FIG. 7, and FIG. 9 is a preferred embodiment of the hammer drive control method according to the present invention. FIG. 10 is an explanatory diagram showing the arrangement of type characters on the type drum in this embodiment, and FIGS. 11 to 16 are explanatory diagrams of the operation of the present invention. 10...Type drum, 12...Hammer, 14...
... Recording paper, 16 ... Ink ribbon, 18 ... Biasing spring, 32 ... Reset cam, 34 ... Evacuation cam, 36 ... Electromagnetic means, 38 ... Armature, 44 ... Clear lever, 46 ... Operation cam ,
L2...deep latch, L1...shallow latch.

Claims (1)

[Scope of Claims] 1. A type drum having a plurality of type characters formed on its outer periphery is driven to rotate, a time when each type is opposed to a printing position is sequentially detected, and a type is placed facing the type drum at the printing position. A multi-digit hammer,
Depending on the timing at which the type faces the printing position and the printing command, the type is flown toward the type drum to print the desired character or symbol on the desired digit, and the hammer is loaded with a biasing spring. The hammers that have been hit are returned to a shallow position by a reset cam, and then moved to a deep latching position by a retraction cam, and the plurality of hammers adjacent to each other are treated as a set and the hammers that have been hit are returned to a shallow position by a reset cam. A plurality of corresponding hammers are held at both latch positions by an electromagnetic means including an armature provided for each hammer, and when printing, the electromagnetic means is activated by a printing command. In a hammer drive control method for an impact printer, the plurality of hammers are operated to release corresponding ones, and the plurality of released hammers are once locked by a reset cam, and then one of the hammers is released to make a mark. , Prior to the printing operation, by rotating the retraction cam 42, all the hammers 12, which were held at the deep latching position L2 by the armature 38, are further moved from the holding position to the biasing force of the biasing spring 18. In this state, the armature 38 corresponding to the hammer 12 that performs at least one printing is moved by the electromagnetic means 36.
The armature 38 is drawn away from the position where it can engage with the hammer 12 by being energized, and then the retraction cam 42 is slightly returned, and the hammer 1
2 is returned to near the shallow latching position L1 by the urging force of each urging spring 18, the energization to the electromagnetic means 36 is cut off, and the armature 38
is engaged with the shallow latch L1 of the hammer 12, and the retraction cam 42 is released from the hammer 12, and then the hammer 1 engaged with the shallow latch L1
2 is pushed up by the rotating reset cam 32, the armature 38 is attracted in the direction away from the hammer 12 by energizing the electromagnetic means 36, and as the reset cam 32 continues to rotate,
The hammer 12 in contact with the reset cam 32 is released and rapidly rotated in the biasing direction by the biasing force of the biasing spring 18 to obtain the desired printing effect. 12, and then all the hammers 12 are pushed up by the retraction cam 34, and the deep latch L of the hammers 12 is pushed up.
2. A hammer drive control method for an impact printer, characterized in that the armature 38 is engaged with the armature 38.