JPS6132155B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printing device, which is one of the terminal devices of an information processing system, and particularly to an impact printer.

Conventionally, the print quality of such printing devices has been adjusted by human visual inspection and manual adjustment. To be more specific, humans visually judged the quality of the printing results produced by the printing device, and then manually adjusted the movement of the platen and print head, controlled the excitation current, and so on.

However, with this method, there may be variations in print quality due to individual differences, and if the clearance between the platen and needle is very narrow, 0.6 to 0.3 mm, as in dot printers, for example, the print quality may be affected. It is extremely difficult to manually adjust the clearance of 0.05 to 0.1 mm while looking at it, and there are also changes in the usage environment of the printing device (e.g. temperature changes, fluctuations in power supply voltage, etc.) and changes in operating conditions over time. This method has disadvantages such as the inability to immediately correct print quality in response to changes in the clearance between the head and the platen (for example, natural changes in the clearance between the head and platen due to mechanical vibration).

This invention has been made to overcome the drawbacks of the prior art. For example, in the case of an impact printer using a hammer, the impact energy of the hammer is directly detected and controlled, thereby making it possible to connect the platen and print. To provide an impact printer that can accurately detect impact energy and adjust the impact energy based on it, maintaining good print quality even when the distance between the device and the device is changed. This is what I am trying to do.

This will be explained in detail below with reference to the figures.

FIG. 1 is a block diagram showing an outline of an embodiment of the present invention. In the figure, 1 is a piezoelectric element, 2 is an A/D converter, 3 is a printing energy control circuit, and 4 is a piezoelectric element.
is the operating environment condition diagnostic circuit, AMP is the amplifier, CPU
indicates the central processing unit, and ROM indicates read-only memory.

A piezoelectric element 1 detects printing energy, and the printing energy detected by the piezoelectric element 1 is sent in the form of electrical energy, amplified by an amplifier AMP, and applied to an A/D converter 2. is converted into a digital signal. This digital signal is compared with the print energy code called from the ROM in the CPU, and the result is used to control the print energy control circuit 3.
Controlled by the CPU. Here, information expressing the printing energy for proper printing is stored in advance in the ROM in the form of a code, and this is called a printing energy code. The operating environment condition diagnosis circuit 4 is a circuit for detecting changes in the environmental conditions in which the printing device is used and transmitting the detected changes to the CPU. Control.

Here, a highly sensitive piezoelectric element 1 is used,
Furthermore, if the resolution of the A/D converter is improved, print quality can be determined with precision that cannot be detected by human senses. For example, the resolution of the A/D converter is 8
If it is a bit, then 2 ⁸ = 256, so 1/2
The printing energy can be detected in units of 56, and when controlling the excitation current of the electromagnet as a printing energy control means, an 8-bit D/A
By using a converter, printing energy can be controlled in 1/256 increments, making it possible to control printing quality with extreme precision.

Furthermore, even when a pulse motor is used as a distance adjustment means to adjust the clearance between the printing head and platen of a dot printer, if a pulse motor with a small step angle is used, it is easier for humans to It allows much more precise control of print energy than manual adjustment that relies on intuition.

FIG. 2 shows a flowchart of the operation of the impact printer according to the present invention, and FIG. 3 shows that the printing energy is controlled by adjusting the distance between the head and the platen by reversible rotation of the head position control pulse motor. The flowchart of the operation in this case is shown below. FIG. 7 is a block diagram of a computer system implementing an impact printer according to the present invention.

The outline of the impact printer according to the present invention will be explained in more detail with reference to the block diagram of FIG. 7 and the flowcharts of FIGS. 2 and 3.

A printing energy code E _cs is stored in advance in the ROM 13 as a storage means, which is an encoded representation of the energy with which the printing device can print with optimum printing quality. Then, when the print head is adjusted or when the print energy control key is pressed as necessary (for example, when a human determines that the print quality is poor), an input flag in the key control logic circuit 11 is activated. becomes 1, thereby causing the interrupt control circuit 10 to act and interrupt the CPU.

Alternatively, when the usage environment condition judgment circuit 4 determines that the ambient environment conditions in which the printing device is used fluctuate and therefore it is necessary to control and adjust the printing energy, the output from the circuit 4 The interrupt control circuit 10 acts to issue an interrupt to the CPU.

In the flowchart of FIG. 2, the case of pressing the print energy control key is shown.

In this way, the operation of the flowchart in Figure 2
CPU comes in. The CPU reads status information from the key control logic circuit 11 through the input/output data bus control circuit 7, the data bus, and the system control circuit/bus driver 9, so that the information represents the press of the print energy control key. When the CPU learns of this, it operates the device selection circuit 8 via the address bus, specifies the print position detection circuit 5, and reads the A mark and the B mark. Based on the results of reading both marks A and B, the print head control circuit 6 is controlled to adjust the print position.

In order to specifically illustrate this relationship, it will be explained with reference to FIGS. 4 and 5. Figure 4a is formed integrally with a carriage that moves parallel to the platen;
This is a cross-sectional view of the sensor block used as the print position detection circuit 5, and FIG. 4b shows a code board for controlling the print position stretched parallel to the platen. Marks A and B consisting of opaque parts are placed on the upper and lower tiers of this code plate.
A cross-sectional view of the sensor block 4 (the same as the position detection circuit, so it is denoted by the same reference numeral 4).
As can be seen from Figure a), a code plate H is inserted through it, and the A mark is read by the combination of the light emitting element A and the light receiving element C in the sensor block 4. The B mark can be read by a combination of elements. now,
Regarding the A mark and B mark of the code board E, when they are opaque, they are set as 1 in binary number, and when they are transparent, they are set as 0 in binary number. The print head is fixed to a sensor block 4, and the CPU reads both the A and B marks on the code plate inserted through the block 4, and depending on the results, controls the motor via the print head control circuit 6. drive to control the position of the print head. FIG. 5 shows the relationship between the reading codes of both marks A and B and the movement of the print head in both left and right directions. The position indicated as HP in Figure 5b is the home position of the print head, and the reading code for both marks A and B at this position is 01.
It is shown in the rightmost column of the table in FIG. 5a. Now, assuming that the print head is at a certain arbitrary position, the sensor block 4 fixed to the print head reads both marks A and B on the code plate, and the result is 11 (Fig. 5 a).
), the CPU drives the motor via the print head control circuit 6 to move the print head to the right, and also controls the sensor block 4.
If the result of reading both marks A and B on the code board is 10 (as shown in Figure 5 a), then the CPU
drives the motor to move the print head to the left. Even if the reading result of both marks A and B is 00 (as shown in Figure 5a), move the print head to the left in the same way. When the print head reaches the home position (HP), the reading result of both marks A and B on the code plate H by the sensor block 4 at that point is 01 (HP in Figure 5a), which is Since the home position is indicated, the CPU finishes controlling the position of the print head.

In this way, when the print head is located at the home position HP, the CPU then selects the magnetic drive circuit 3-1 via the device selection circuit 8.
and N ₁ magnet is specified, the CPU sends the N ₁ magnet drive command through the system control circuit and bus driver 9 and the input/output data bus control circuit 7.

The printing energy is detected by the excitation of the _N1 magnet, and FIG. 6 will be referred to to explain this relationship. FIG. 6 shows a printing energy detection mechanism as a detection means necessary for the impact printer according to the present invention. In the figure, ri is a platen, nu is a printing paper, ru is a print head, e is a code plate for head position detection, and 1 is a piezoelectric element.

The needle of the print head collides with the piezoelectric element 1 due to the excitation of the _N1 magnet. As a result, the electrical energy generated in the piezoelectric element 1 represents the printing energy, and this energy is amplified through the amplifier AMP,
applied to the control logic circuit and the A/D converter 2;
Here the energy is converted into a binary code (denoted E _c ). Control logic circuit and A/
The D converter 2 sends status information indicating that the conversion has been completed to the CPU serving as comparison means. The CPU thereby selects the control logic circuit and the A/D converter 2 by the device selection circuit 8 via the address bus.
is captured, and the energy code E _c in this circuit 2 is read through the input/output data bus control circuit 7 and the system control circuit/bus driver 9.

Next, the CPU transfers ROM1 via the address bus.
3, and the print energy code E _cs previously stored in the ROM is read through the system control circuit and bus driver 9 via the memory data bus. If the two codes do not match, print energy control is performed to adjust the excitation current of the _N1 magnet, and then the print head needle collides with the piezoelectric element again to detect the print energy. Compare E _c and E _cs in the same way as above. If both codes match, printing energy control ends. The above is an outline of the operation along the flowchart of FIG.

The flowchart in Figure 3 shows how printing energy is controlled.
The case is shown not by adjusting the excitation current of the _N1 magnet, but by adjusting the distance between the print head and the platen. In other words, as a result of comparing E _c and E _cs in the CPU, E _c < E _cs and CPU
If so, the CPU selects the pulse motor through the device selection circuit 8 via the address bus.
Specify the drive circuit 3-2, and the system control circuit and bus driver 9 for the pulse motor.
A signal is sent through the input/output data bus control circuit 7 to move the printing head forward (in the F direction) as shown in FIG. Conversely, when it is determined that E _c >E _cs , the pulse motor is similarly reversed to move the print head backward (in the R direction). and E _c = E _cs
When the CPU determines that this is the case, the CPU ends control.

Even if E _c and E _cs do not completely match, the control may be terminated if the difference falls within a certain range.

As explained above, this invention is based on a novel method that has never been seen before, in which printing energy is directly detected and printing energy is controlled based on it. Even when the interval between the two is changed, the print quality is always excellent and constant, which is an outstanding effect.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an overview of an embodiment of the present invention, Fig. 2 is a flowchart of the operation of the impact printer according to the invention, and Fig. 3 shows a case where printing energy is controlled by a head position control pulse motor. Fig. 4a is a sectional view of the sensor block, Fig. 4b is a diagram showing the code plate for head position control, Fig. 5a is the reading code of both marks A and B on the code plate and the position of the code plate. 5b is a diagram showing how the position of the print head is adjusted with respect to the code plate, FIG. 6 is a diagram showing the printing energy detection mechanism in the impact printer according to the present invention, and FIG. 7 is a diagram showing the adjustment of the print head position with respect to the code plate. 1 is a block diagram of a computer system in which an impact printer is implemented. In the figure, 1 is a piezoelectric element, 2 is an A/D converter, 3 is a printing energy control circuit, 4 is a usage environment condition diagnostic circuit, AMP is an amplifier, CPU is a central processing unit, ROM is a read-only memory, and ROM is a read-only memory. 1 is a code plate, A and B are light emitting elements, C and D are light receiving elements, A and B are opaque marks, R is a platen, N is a printing paper, and R is a print head. In particular, in FIG. 7, 1 is a piezoelectric element, 2 is a control logic circuit and an A/D converter, and 3 is a piezoelectric element.
-1 is a magnet drive circuit, 3-2 is a pulse motor drive circuit, 4 is a usage environment condition judgment circuit, 5 is a print position detection circuit, 6 is a print head control circuit, 7 is an input/output data bus control circuit, 8 is a device selection circuit, 9 is a system control circuit and bus driver, 10 is an interrupt control circuit, 11 is a key control logic circuit, 12 is a clock generator, 13
indicates ROM.

Claims (1)

[Scope of Claims] 1. An impact printer comprising a platen, a printing means, and a distance adjusting means for changing the distance between the platen and the printing means, at a position opposite to the printing means. sensing means for directly detecting the impact energy applied by the printing means to the platen, irrespective of changes in the spacing between the printing means and the platen, and for storing information regarding the impact energy; a storage means for comparing the output read from the storage means with an output from the detection means; and an impact energy control means for controlling the impact energy in response to the output from the comparison means; An impact printer characterized by: