JPH11300954A - Printer, and method and apparatus for driving head thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable high speed printing in a desired printing region. SOLUTION: A busy signal is generated during one emitting cycle emitting ink by driving a head corresponding to an emitting demand and the generation period of the busy signal is set so that the emission of a next emitting cycle is delayed up to a point of time when the busy signal falls even if there is a next emitting demand and the interference of before and behind emitting cycles is prevented. When there is no next emitting demand during the generation period of the busy signal, emission is started at a point of time when the next emitting demand is generated. Since an 'idling period' is not required within one emitting cycle, high speed printing becomes possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer, a method of driving a head thereof, and a driving apparatus thereof, and more particularly, to a method of driving an ink jet head capable of correcting ink ejection timing.

[0002]

2. Description of the Related Art Ink-jet printers print by ejecting ink from a head onto a sheet of recording medium in a jet-like manner. The mechanism of this head utilizes the pressurization of an ink chamber by a piezo element. There is. About the conventional driving method of this mechanism
This will be described with reference to those described in 1995, pages 36 to 37. FIG.
As shown in FIG. 1, the head 10 is provided with the nozzle 1 for discharging ink.
1 and a plurality of piezo elements 13 for pressurizing the walls of the ink chamber 12 (only one is shown). Condition the ink before ejection. Then, the ink is discharged by “ink chamber reduction”, and “ink chamber expansion 2”
Then, the ink chamber is enlarged again, the ink is drawn, and the ink droplet after ejection is separated. Thereafter, an “idling period” is provided. When ink is ejected to a predetermined position on the paper by the above-described driving method, the head is set at a predetermined traveling speed, and the head is moved to perform “ink chamber expansion 1” → “ink chamber reduction” → “ink chamber expansion” at each predetermined position. Ink is ejected by repeating one ejection cycle of “2” → “idling period”.
In the above, the "idling period" is provided because the traveling speed of the head is set to a predetermined speed, but the actual mechanical speed is not completely constant, and therefore the traveling time between the predetermined positions is not completely constant. No, only "ink chamber expansion 1" → "ink chamber reduction" → "ink chamber expansion 2"
If the running time is short when the head is operated at the ejection cycle,
There is a possibility that the operation of the next one ejection cycle may be started before the one ejection cycle is finished. In consideration of this point, the printing of the next cycle is performed after the one ejection cycle is completely completed. It is.

[0003]

As described above, in the above-described mechanism, in the conventional driving method, an "idling period" is provided in one ejection cycle of ink, and "ink chamber expansion 1" is performed.
Since the operation of “ink chamber reduction” → “ink chamber expansion 2” is prevented from colliding in one back and forth ejection cycle, there is a problem that the printing speed is reduced by this “idling period”. The present invention has been made in view of the above-mentioned problems, and “Ink chamber expansion 1” → “Ink chamber reduction” →
An object of the present invention is to provide a printer, a head driving method thereof, and a driving device thereof, in which the operation of “ink chamber expansion 2” does not collide with one ejection cycle before and after.

[0004]

According to a method of driving a head of a printer according to the present invention, a head is driven for one ejection cycle in response to an ejection request signal to eject ink.
The head is not driven by the next ejection request signal. In the method of the present invention, when the next ejection request signal is generated in one ejection cycle, the head is driven at the end of one ejection cycle, and when the next ejection request signal is generated after the end of one ejection cycle, The head is driven when the ejection request signal is generated. Further, a busy signal pulse is generated during one ejection cycle, and the end point of one ejection cycle is defined as the time point at which the busy signal pulse falls. Further, the head includes an ink chamber connected to the nozzle and a piezo element for pressurizing a wall of the ink chamber. The head drive device of the printer according to the present invention drives the head in one ejection cycle according to the ejection request signal to eject ink, and does not drive the head by the next ejection request signal during this one ejection cycle. . In the apparatus of the present invention, when the next ejection request signal is generated in one ejection cycle, the head is driven at the end of one ejection cycle, and when the next ejection request signal is generated after the end of one ejection cycle, The head is driven when the next ejection request signal is generated. Specifically, the apparatus of the present invention includes an output circuit that generates a drive signal to the head and generates a busy signal generated during one discharge cycle, and that the next discharge request signal is generated during the generation period of the busy signal. If it occurs, a timing signal is generated at the time when the busy signal falls, and if a next ejection request signal is generated when no busy signal is generated, a timing signal is generated at the time when the next ejection request signal occurs. And a correction circuit. A printer of the present invention includes an ink chamber in which a head is connected to a nozzle, and a piezo element for pressurizing a wall of the ink chamber, and uses the head driving device of the present invention.

[0005]

Embodiments of the present invention will be described below with reference to FIGS. First, a method for driving a printer according to the present invention will be described with reference to FIG. The present invention is characterized by a method of setting an ejection timing for driving a head for one ejection cycle according to an ejection request signal when ink is ejected onto a recording medium by relatively moving a print head and a recording medium. The method will be described. As the relative traveling between the head and the recording medium, for example, when the head is moved in the row direction with respect to the recording medium, an ejection request signal is generated at timings T1, T2, and T3. When the head is driven, a busy signal having a constant width for one ejection cycle is generated. (1) A timing signal is generated at the generation time T1 of the first ejection request signal, the ejection of the first cycle is started, and a pulse of a busy signal is generated with a delay of one clock signal. (2) When the travel time of the head from the time T1 when the ejection of the first cycle is started to the time T2 when the second ejection request signal is generated is longer than the pulse width of the busy signal, the time when the second ejection request signal is generated At T2, a timing signal is generated to start the ejection of the second cycle and to generate a busy signal pulse delayed by one clock signal. (3) If the travel time from the time T2 at which the ejection of the second cycle is started to the time T3 at which the third ejection request signal is generated is shorter than the pulse width of the busy signal, at the time T3 at which the third ejection request signal is generated, The discharge in the third cycle is not started, and a standby state is set. Thereafter, a timing signal is generated at time T4 when the discharge in the second cycle is completed and the pulse of the busy signal falls, and the discharge in the third cycle is performed. When started, a pulse of a busy signal is generated with a delay of one clock signal. (4) Hereinafter, the head is caused to travel in a line with respect to the recording medium, and one ejection cycle is repeated by one of the methods (2) and (3) until the end of the predetermined area of printing, and every time the head is driven to reach the end by (1) )
Then, the next traveling line is printed on a predetermined area of the recording medium by repeating one ejection cycle in the same manner.

According to the method described above, when the head is driven for one ejection cycle by an ink ejection request signal while the head is running in line with the recording medium, the ink is periodically ejected onto the recording medium. A busy signal is generated for one ejection cycle. Then, when the ejection request signal of the next cycle is generated during the generation period of the busy signal, the ejection is started at the time when the busy signal falls, so that it is possible to prevent the previous and next ejection cycles from colliding with each other. Since it is not necessary to provide an "idling period" in the ejection cycle, high-speed printing is possible.

Next, an embodiment of a printer using a driving device according to the present invention for realizing the above driving method will be described with reference to FIGS.
This will be described with reference to FIG. The printer, as shown in FIG.
Control device 20 for outputting ejection request signal, print data, etc.
A driving device 30 that outputs a driving signal in response to an ejection request signal from the control device 20;
A head 10 for ejecting ink at each ejection cycle.

The control device 20 is, for example, a computer including a ROM and a RAM, and controls the operation of the entire printer in accordance with a control program stored in the ROM. The ROM stores character font data and the like in addition to the control program. The RAM is used as a work area at the time of control operation and stores print data and various data. The control device 20 supplies a clock signal, an ejection request signal, and a print data signal to the drive device 30. The ejection request signal is supplied based on an encoder signal detected at the time of running of the head by a not-shown encoder at a predetermined ejection position set as a requested position of ink ejection. The interval between the ejection request signals becomes narrower when the actual mechanical traveling speed of the head is faster than the case where it matches the set speed,
If it is slow, it will be wider.

The driving device 30 corrects the ejection request signal and outputs a timing signal for ink ejection.
An output circuit 32 that outputs a drive signal based on print data from the control device 20 and a timing signal from the correction circuit 31, and outputs a busy signal to the correction circuit 31 to notify that the drive signal is being output; It is composed of The correction circuit 31 generates a timing signal based on the busy signal from the output circuit 32 and the ejection request signal from the control device 20, and supplies the timing signal to the output circuit 32. If the next ejection request signal is supplied while the busy signal pulse is being supplied, a standby state is set from the time of this rising to the time of the falling of the busy signal pulse, and a timing signal is output at the time of the falling. If the next ejection request signal is supplied while the pulse of the busy signal is not supplied, the timing signal is output from the time when the ejection request signal rises. The output circuit 32 supplies a drive signal corresponding to the print data from the control device 20 to the head 10 in synchronization with the timing signal from the correction circuit 31, and outputs a busy signal indicating that the drive signal is supplied to the head 10. The signal is supplied to the correction circuit 31 for one ejection cycle in synchronization with the next clock signal at which the signal has risen.

As shown in FIG. 3, a head 10 has an ink chamber 12 connected to a nozzle 11 for discharging ink, as in the prior art.
And a piezo element 1 for pressurizing the wall of the ink chamber 12
3 (only one is shown), and is mounted on a carriage (not shown) and travels in the row direction while supplying a drive signal from the drive device 30 to the piezo element to print ink as a recording medium. The printing is performed on a predetermined area of the paper based on the print data by discharging the ink on the paper and causing the paper to intermittently travel in the column direction every time in the row direction.

Next, the operation of the printer having the above configuration will be described. As shown in FIG. 3, the piezoelectric element 1 of the head 10
The relationship between the waveform of the drive signal and the state of the ink chamber 12 when ink is ejected once from the nozzles 11 of the head 10 for each ejection cycle of the drive signal supplied to 3 is as follows: “Ink chamber expansion 1” → “ink chamber reduction” → “ink chamber expansion 2”, ink chamber is expanded by “ink chamber expansion 1”, ink is drawn to adjust the state of ink before ejection, and “ink chamber reduction” To eject ink,
In “ink chamber expansion 2”, the ink chamber is expanded again, and the ink is drawn to separate the ink droplets after ejection.

The operation of the printer when ink is ejected to a predetermined position on a sheet using the above-described one ejection cycle will be described with reference to a time chart of FIG. When a print command is given to the control device 20 from a host computer, which is an external device, the head with the traveling speed set to a predetermined speed is driven by the control device 20.
The vehicle is controlled in the line direction. (1) When the head reaches the first predetermined position, the head is detected and the pulse of the ejection request signal is supplied from the control device 20 to the correction circuit 31. At this time, since the correction circuit 31 is not supplied with the busy signal pulse from the output circuit 32,
At the rising time t1 of the pulse of the ejection request signal, a pulse of the timing signal is supplied from the correction circuit 31 to the output circuit 32, and a drive signal is supplied from the output circuit 32 to the head in synchronization with the pulse, and the ejection of the first cycle is performed. At the same time, the pulse of the busy signal is supplied to the correction circuit 31 with a delay of one clock.

(2) When the traveling time of the head from the first predetermined position, that is, the position where the discharge of the first cycle is started to the second predetermined position, is longer than one discharge cycle, the head is moved to the second predetermined position. , The first cycle of ejection is completed, and the pulse of the busy signal falls. When the head reaches the second predetermined position at the time point t2, this is detected and a pulse of the ejection request signal is supplied from the control device 20 to the correction circuit 31. At this time, as in (1), since the busy signal pulse is not supplied from the output circuit 32 to the correction circuit 31, the timing signal pulse is supplied to the output circuit 32 at the rising point t2 of the pulse of the ejection request signal, and the output circuit 32 outputs the pulse. A drive signal is supplied from the circuit 32 to the head in synchronization with this, and the ejection of the second cycle is started, and the correction circuit 3
1 is supplied with a busy signal pulse as in (1).

(3) If the traveling time of the head from the second predetermined position, that is, the position at which the discharge of the second cycle is started to the third predetermined position, is shorter than one discharge cycle, the head moves to the third predetermined position. At time t3 when the head arrives, the ejection in the second cycle is not completed, and the pulse of the busy signal is still supplied to the correction circuit 31. When the head reaches the third predetermined position, it is detected and a pulse of the ejection request signal is supplied from the control device 20 to the correction circuit 31. Since the correction circuit 31 is supplied with the busy signal pulse from the output circuit 32 at this time t3, the timing signal pulse is output from the output circuit 32 at the rising time t3 of the ejection request signal pulse.
The ejection of the third cycle is in a standby state, and then the pulse of the timing signal is supplied to the output circuit 32 at time t4 when the ejection of the second cycle is completed and the pulse of the busy signal falls, A drive signal is supplied from the output circuit 32 to the head in synchronization with this, to start ejection in the third cycle, and a pulse of a busy signal is supplied to the correction circuit 31.

(4) If the traveling time of the head from the position where the ejection of the third cycle is started to the fourth predetermined position is shorter than one ejection cycle, the head is moved to the fourth predetermined position at time t5 when the head reaches the fourth predetermined position. The ejection in the third cycle is not completed, and the pulse of the busy signal is still supplied to the correction circuit 31. 4th
When the head reaches the predetermined position, the controller 20 detects this and supplies a pulse of the ejection request signal to the correction circuit 31 from the control device 20. The correction circuit 31 outputs the output circuit 3 at time t5.
Since the pulse of the busy signal is supplied from 2, the pulse of the timing signal is not supplied to the output circuit 32 at the rising time t <b> 5 of the pulse of the ejection request signal, and the ejection in the fourth cycle is in a standby state. Time point t6 when the ejection of the cycle is completed and the pulse of the busy signal falls
, A pulse of a timing signal is supplied to the output circuit 32, and a drive signal is supplied from the output circuit 32 to the head in synchronization therewith to start ejection in the fourth cycle and supply a pulse of a busy signal to the correction circuit 31 Is done.

(5) When the traveling time of the head from the position where the ejection of the fourth cycle is started to the fifth predetermined position is longer than one ejection cycle, the time t7 is reached until the head reaches the fifth predetermined position. Then, the ejection of the fourth cycle is completed, and the pulse of the busy signal falls. When the head reaches the fifth predetermined position at time t8, this is detected, and the controller 20 supplies a pulse of the ejection request signal to the correction circuit 31. At this time t8, since the busy signal pulse is not supplied from the output circuit 32 to the correction circuit 31, the timing signal pulse is supplied to the output circuit 32 at the rising time t8 of the ejection request signal pulse. In synchronization with this, a drive signal is supplied to the head to start the ejection in the fifth cycle, and a busy signal pulse is supplied to the correction circuit 31.

(6) Thereafter, the head is similarly driven in the row direction, and one ejection cycle is repeated until the end of the row in a predetermined area of printing.
Each time the paper travels in the row direction, the paper is intermittently traveled in the column direction, and one ejection cycle is similarly repeated to perform printing based on the print data on a predetermined area of the paper.

As described above, the timing signal is supplied from the correction circuit 31 to the output circuit 32 for each ejection request signal from the control device 20 while the head 10 travels in the row direction on the recording medium. When the head 10 is driven for one ejection cycle by a drive signal of the output circuit 32 synchronized with the signal to eject ink onto the recording medium, the output circuit 32 generates a busy signal for one ejection cycle of the drive signal. When the ejection request signal of the next cycle is supplied from the control device 20 during the generation period of the busy signal, the timing signal is supplied from the correction circuit 31 to the output circuit 32 at the time when the busy signal falls. It prevents the front and rear ejection cycles from colliding. When the ejection request signal is supplied from the control device 20 after the fall of the busy signal, the timing signal is supplied from the correction circuit 31 to the output circuit 32 at the time when the ejection request signal is supplied. As a result, the “idling period” is set within the ejection cycle as in the related art.
, It is possible to perform high-speed printing.
Incidentally, the head is not limited to the above-described embodiment, for example, a head using expansion by heating of ink,
What is necessary is to literally eject ink to a recording medium like a jet.

[0019]

According to the present invention, a method for discharging ink 1 is provided.
During the ejection cycle, a busy signal pulse is generated.While the busy signal pulse is being generated, the next ejection request is not started even if there is a next ejection request, and is delayed as a standby state. By starting the discharge at the time of falling, it is possible to prevent the discharge cycle from hitting before and after. Then, when there is no next ejection request while the busy signal pulse is being generated, the ejection is started before the next ejection request at the time when the busy signal pulse falls. Since the delay and advance of the ejection timing can be canceled within the frame of the predetermined area of printing, printing can be performed in the predetermined area, and it is not necessary to provide an "idling period" in the ejection cycle as in the related art. Printing becomes possible.

[Brief description of the drawings]

FIG. 1 is a time chart illustrating a method for driving a head of a printer according to the present invention.

FIG. 2 is a block diagram showing an embodiment of a printer according to the present invention.

FIG. 3 is a diagram for explaining the operation of the printer of FIG. 2 for one ejection cycle of the head.

FIG. 4 is a time chart illustrating the operation of the correction circuit of the printer of FIG. 2;

FIG. 5 is a diagram illustrating an operation of a head in one ejection cycle in a conventional printer driving method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Head 11 Nozzle 12 Ink chamber 13 Piezo element 20 Control device 30 Drive device 31 Correction circuit 32 Output circuit

Claims (8)

[Claims] 1. A head driving method for a printer, wherein a head is driven by one ejection cycle according to an ejection request signal to eject ink, and during this one ejection cycle, the head is not driven by the next ejection request signal. 2. When the next ejection request signal is generated in the one ejection cycle, the head is driven at the end of the one ejection cycle, and when the next ejection request signal is generated after the end of the one ejection cycle, 2. The method according to claim 1, wherein the head is driven when the next ejection request signal is generated. 3. A head driving method for a printer according to claim 1, wherein a busy signal is generated during said one ejection cycle, and an end point of said one ejection cycle is a point in time when said busy signal falls. 4. The method according to claim 1, wherein the head includes an ink chamber connected to the nozzle and a piezo element for pressing a wall of the ink chamber. 5. A head driving device for a printer, wherein a head is driven for one ejection cycle by an ejection request signal to eject ink, and during this one ejection cycle, the head is not driven by the next ejection request signal. 6. When the next ejection request signal is generated in the one ejection cycle, the head is driven at the end of the one ejection cycle, and when the next ejection request signal is generated outside the one ejection cycle, 6. The head driving device for a printer according to claim 5, wherein the head is driven when the next ejection request signal is generated. 7. An output circuit for generating a drive signal to the head and for generating a busy signal generated during the one discharge cycle, and when the next discharge request signal is generated during the generation period of the busy signal, A correction that generates a timing signal at the time of the fall of the busy signal and generates the timing signal at the time of the generation of the next ejection request signal when the next ejection request signal occurs when the busy signal is not generated 7. The printer head driving device according to claim 6, further comprising a circuit, wherein the driving signal is generated in synchronization with the timing signal. 8. A printer using a head driving device according to claim 5, wherein said head includes an ink chamber connected to a nozzle and a piezo element for pressing a wall of the ink chamber.