JPH0530928Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention can automatically adjust the gap between the print head and the paper surface (hereinafter referred to as the print head gap) to a constant value, and also This invention relates to a print head gap adjustment device that can be manually adjusted to any desired value.

[Prior art] Dot impact printers print dots by pressing an ink ribbon against paper using a print wire in the print head, so it is necessary to adjust the gap between the print heads depending on the thickness of the paper. . That is, when the paper is thin and the gap between the print heads becomes large, the printing pressure becomes weaker, resulting in a thinner print. Conversely, when the paper is thicker and the gap between the print heads becomes smaller, the printing pressure becomes stronger and the print becomes darker.
When the print head gap becomes smaller, the recording paper comes into contact with the ink ribbon and becomes dirty, the print wire gets damaged, and the wire itself wears out, shortening its lifespan.

Furthermore, even when the ink ribbon itself is worn out, it is necessary to adjust the gap between the print heads to prevent deterioration in print quality.

Therefore, in conventional printers of this type, the print head is moved up and down according to the paper thickness by operating a lever, so that the gap between the print heads can be manually adjusted to an arbitrary value. In recent years, a composite gap adjustment device has been developed that combines this manual gap adjustment method with an automatic gap adjustment method.

That is, by operating a lever to enter automatic adjustment mode, the gap between the print heads can be automatically adjusted to a constant value according to the paper thickness.
By switching the lever to manual adjustment mode, the gap between the print heads can be manually adjusted to a desired value.

[The problem that the idea attempts to solve]

However, in the composite type gap adjustment device currently under development, once the gap of the print head is adjusted, even if the lever is switched while the printer is operating, the gap will not be adjusted according to the switching position. . In other words, for switching from manual adjustment mode to automatic adjustment mode, switching from automatic adjustment mode to manual adjustment mode, and switching to a set position within manual adjustment mode, if the printer is operating, the switching No gap adjustment is made corresponding to the position.

For this reason, for example, first set the print head gap in manual adjustment mode to a value that corresponds to the thickness of three sheets of standard paper, and then after printing is completed, set the next paper to be used as thick as one sheet of paper. When printing on paper, if you leave the gaps as they are, the density of the print on the paper will be reduced. Of course, even if you switch from manual adjustment mode to automatic adjustment mode, or from automatic adjustment mode to manual adjustment mode, or change the setting position of the lever in manual adjustment mode, the print head gap will not change and during printing In this case, the gap between the print heads is not adjusted and the print density on the paper cannot be set to an appropriate value.

[Means to solve the problem]

The present invention has been made to solve such problems, and is designed to detect changes from manual adjustment mode to automatic adjustment mode and from automatic adjustment mode to manual adjustment mode, and to detect changes in the detected mode. The system prompts readjustment of the print head gap based on the change.

[Effect]

Therefore, according to this invention, even when the printer is in operation, if a change in mode is detected, readjustment of the print head gap occurs.

〔Example〕

Hereinafter, the printing head gap adjusting device according to the present invention will be explained in detail.

FIG. 2 is a side view showing the main parts of a horizontal multicolor printer to which an embodiment of this print head gap adjustment device is applied. Guide plate 2 arranged as
A, 2b are detected by a paper feed sensor 3 such as a light emitting diode and a light receiving transistor provided facing each other, and as the transport motor 4 rotates according to the detected force, the gears 5, 6, Rollers 9 and 10 rotate in the direction of the arrow via pulley 7 and belt 8, and the paper is held between holding rollers 11 and 12 that come into contact with rollers 9 and 10, and is transported to the right in the figure.

However, between the rollers 9 and 10, a platen 13 is provided on the lower side, and a wire dot printing type printing head 14 is provided on the upper side opposite to the platen 13. A paper edge sensor 15 similar to the sensor 3 is provided, and when the leading edge of the paper is detected by this sensor, the printing start position of the paper is determined from the print head 14 based on this position.
Since the distance to be moved until they coincide with each other directly below is determined, the motor 4 is stopped after this distance has been moved, and the printing standby state is entered.

The print head 14 is operated by a mechanism not shown in the figure.
It moves both left and right when viewed from the supply port 100 side, and is supported so as to be able to move forward and backward in a direction perpendicular to the paper surface. The AGA lever 29 is provided to protrude outward from the main body of the printer.
maximum switching position in the direction of arrow A (0 shown in the figure)
position) is the automatic adjustment mode position for adjusting the gap of the print head 14, and the switching position of the AGA lever 29 other than the automatic adjustment mode position is the manual adjustment mode position for adjusting the gap of the print head 14. It is said that That is, by moving the AGA lever 29 from the automatic adjustment mode position in the direction of arrow B in the figure, the AGA lever 29 is switched to the manual adjustment mode position.
By increasing step by step in direction B,
The opposing gap between the print head 14 and the platen 13 widens step by step. In this embodiment, it is possible to switch to three set positions from the illustrated position to the position shown in the manual adjustment mode position. In addition, by switching the AGA lever 29 to the automatic adjustment mode position, this
A stopper portion of a detent lever (not shown) that cooperates with the AGA lever 29 comes into contact with the actuator portion 24a of the AGA detection switch (limit switch) 24, turning on the AGA detection switch 24, and the AGA lever 29 is turned on. By switching from the automatic adjustment mode position to the manual adjustment mode position, the stopper part of the detent lever moves to the AGA position.
By moving away from the actuator section 24a of the detection switch 24, the AGA detection switch 24
is set to be turned off. And this
The gap between the print heads 14 is adjusted based on the switching position of the AGA lever 29, and as printing starts, the print heads 14 move in both left and right directions to print, and when printing for one line is completed, the motor 4 rotates to create a new line, then print head 14
printing is performed while moving in the opposite direction, and the above-mentioned operations are repeated, and as printing progresses, the paper is gradually transferred to the discharge port 16 on the right side in the figure.

Further, when the trailing edge of the paper passes the paper edge sensor 15, the trailing edge is detected by a change in the output of the paper end sensor 15, and the printing position of the last line of the paper is determined based on this position.

FIG. 3 is a cutaway perspective view of the main parts showing how the print head 14 is supported. A cartridge 18 for the ink ribbon 17 is detachably attached to both side plates (not shown), and a lower guide is attached to the back of the cartridge 18. Shaft 19 and Atsupa guide shaft 2
0 is arranged, and a carriage 21 is provided to be fitted into the lower guide shaft 19 and upper guide shaft 20. That is, a carriage 21 is held on a lower guide shaft 19 and an upper guide shaft 20 that are arranged parallel to each other so as to be slidable in the left and right directions in the figure via slide bearings 21a and 21b. A print head 14 is mounted.
A lower guide shaft 19 and an upper guide shaft 20 are supported so as to be movable in the vertical direction. Of these guide shafts, the upper guide shaft 20 has an eccentric bearing structure, and an eccentric cam constituting this eccentric bearing structure. The printing head 14 is configured to freely move forward and backward relative to the paper surface depending on the rotational angular position of the printer (not shown). In other words,
By rotating the eccentric cam, the upper guide shaft 20 and the lower guide shaft 19 move up and down, and the tip 1 of the platen 13 and print head 14
4a can be adjusted, and the rotation angle position of this eccentric cam is feedback-controlled by the detection force of the cam position detection sensor (25 shown in Fig. 4). There is.

Further, the carriage 21 is provided with a holder 22 in addition to the print head 14.
At the same time, the paper is guided to the platen section by 2.
This stabilizes the running operation of the ink ribbon 17. In addition, an ID read sensor 23 is fixed to the holder 22 with its sensing portion facing downward, and the ID read sensor 23 targets a portion of the paper in the left and right direction that is approximately the same as the tip 14a of the print head 14, and emits light. and receives the reflected light, and moves as one unit with the print head 14 to create an ID.
The mark is read optically.

The ink ribbon 17 is divided into two in the width direction, with a black band 17a at the front and a red band 17b at the rear.
26) shown in the figure, the ink ribbon 17 is moved along with its cartridge 18 by the arrow shown in the figure.
The black band 17a that was ejected in the A′ direction until then
The black printing mode using the red band 17b can be switched to the red printing mode using the red band 17b.

FIG. 4 is a block diagram showing the configuration of the control circuit that controls the control operations in the horizontal multicolor printer configured as described above.
_31-1 , _PROM31-2 , _RAM31-3 , print head control circuit _31-4 , interface circuit _31-5
and _31-6, etc., a main control unit (master unit) 31, a slave CPU _32-1 , and a PROM.
32 _-2 , control circuit 32 _-3 , ribbon switching circuit 32 _-4
and a sub-control section (slave section) 32 composed of a timing generation circuit _32-5 and the like. The master section 31 and slave section 32 are interconnected via an interface circuit _31-6 , and commands from the host computer are input to the master section 31 via the interface circuit _31-5 . It has become something that is done. In the figure, 27 _-1 to 27 _-o are motor groups whose rotational operations are controlled by the control circuit 32 _-3 in the slave section 32. For example, 27 _-1 is a motor group that rotates in the left and right direction of the print head 14. 27 _-o is a drive motor that controls the vertical movement of the print head 14 .

FIG. 5 shows that in the master section 31, the master
This is a flow chart of the main part of the control (print head gap adjustment control) performed by the CPU _31-1 , and below, based on this flow chart, the gap adjustment control operation of the print head 14 during printer operation will be explained.

That is, for example, if we now start printing on paper with the AGA lever 29 in the manual adjustment mode position (501), first, the current gap between the print head 14 and the platen 13 is adjusted to the manual adjustment mode position. It is checked whether the gap corresponds to the position. (Step 502).
If the gap between print head 14 and platen 13 is not the gap corresponding to the position in the manual adjustment mode position, it is adjusted to the gap corresponding to the position in step 503. This gap adjustment is performed by raising or lowering the print head 14 by a predetermined amount relative to the platen 13. In this way, after the gap between the print head 14 and the platen 13 is set to a gap corresponding to the position, actual printing on the paper is started (step 504). During this printing operation, the completion of the printing operation and the change in switch mode in the AGA detection switch 24 are monitored in steps 505 and 506. During this printing operation, when a change in the switch mode in the AGA detection switch 24 is detected in step 506, the printing operation is interrupted when printing for one line currently being printed is completed (step 507), and the print head is 14 is returned to its home position and the gap is readjusted (step 508).

That is, if you want to deal with changes in the thickness of the paper to be printed by setting the gap between the print head 14 and the platen 13 to a value corresponding to the position in the manual adjustment mode position, for example, the AGA lever 29
By temporarily switching to the automatic adjustment mode position and then setting it again to the manual adjustment mode position, the setting can be changed even while the printer is in operation. That is, when the AGA lever 29 is switched from the manual adjustment mode position to the automatic adjustment mode position, the stopper part of the detent lever that cooperates with this AGA lever 29 is activated by the AGA detection switch 2.
4, the switch mode of this AGA detection switch 24 changes from the off state to the on state. Then, when the AGA lever 29 is switched to the manual adjustment mode position, the stopper part of the detent lever is
Actuator section 24 of AGA detection switch 24
a, the switch mode changes from the on state to the off state, and prompted by the change in the switch mode of the AGA detection switch 24, the print head 14 changes to the value corresponding to the position in the manual adjustment mode position. The gap between the platen 13 and the platen 13 is readjusted. Then, based on the printing command after readjusting the gap, the process returns to step 504.
Printing on paper resumes. In other words, even if the thickness of the paper to be printed on is made thinner or thicker while the printer is operating, there is no way to cope with the thickness of the paper.
If the manual adjustment mode position of the AGA lever 29 is changed past the automatic adjustment mode position, the gap between the print head 14 and the platen 13 will be readjusted, and the print density on the changed paper will become lighter or darker. There will be no problems such as being lost.

Of course, even if you want to switch from manual adjustment mode to automatic adjustment mode or from automatic adjustment mode to manual adjustment mode while the printer is operating, the change in switch mode will occur at the AGA detection switch 24, so you will have to follow the steps. At step 508, the gap is readjusted according to the switching mode position. To adjust the print head gap in the automatic adjustment mode position, operate the print head 14 until it is pressed against the paper surface, and then move the print head 1 a certain distance from this state.
This is done by retracting 4.

FIG. 1 is a functional block diagram corresponding to the main part of the flowchart shown in FIG. Changes in the switch mode of the detection switch 24 are monitored, and the AGA
When a change in the switch mode of the detection switch 24 is detected, the block 42 interrupts the printing operation of the print head 14 driven, and at the same time prompts the block 43 to set the value corresponding to the switching position of the AGA lever 29. Then adjust the gap between the print heads 14. After adjusting this gap, block 4
A signal is given to 2 to restart the printing operation.

[Effect of idea]

As explained above, according to the print head gap adjustment device according to the present invention, a change from manual adjustment mode to automatic adjustment mode and a change from automatic adjustment mode to manual adjustment mode are detected, and the detected mode The change prompts you to readjust the printhead spacing, so even if the printer is running, if the mode change is detected, the printhead spacing will be readjusted. In response to changes in paper thickness, it is possible to set the print density on the paper to an appropriate value.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram corresponding to the main part of the flowchart shown in FIG. 5, and FIG. 2 is a horizontal multicolor printer to which an embodiment of the print head gap adjustment device according to the present invention is applied. A side view showing the main parts of
FIG. 3 is a cutaway perspective view of the main parts of FIG. 2 showing how the printing head is supported, FIG. 4 is a block diagram showing the configuration of a control circuit that controls control operations in this horizontal multicolor printer, and FIG. The figure is a flow chart of the main part of the print head gap adjustment control performed by the master CPU in this control circuit. 14...Print head, 24...AGA detection switch, 29...AGA lever, 41...Switch mode monitoring block, 42...Print head drive block, 43...Gap adjustment block.

Claims (1)

[Scope of utility model registration request] Automatic gap adjustment means adjusts the gap between the print head and paper surface to a constant value according to the paper thickness by using automatic adjustment mode, and adjusts the gap between the print head and paper surface to an arbitrary value by setting it to manual adjustment mode. In the print head gap adjustment device comprising manual gap adjustment means for adjusting the gap to a value, mode change detection means detects a change from the manual adjustment mode to the automatic adjustment mode and a change from the automatic adjustment mode to the manual adjustment mode. and a gap readjustment means for prompting readjustment of the gap of the print head based on the mode change detected by the mode change detection means.