JP3171084B2 - Ink jet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus, and more particularly to a technique for discharging electric charges charged in a bypass capacitor when the power of the apparatus is turned off.

[0002]

2. Description of the Related Art In a conventional ink jet recording apparatus, when a print head is driven, a large peak current flows when the applied voltage rises, so that a voltage drop occurs. A bypass capacitor is provided in a drive circuit of the print head. In this device, when the power of the device is turned off, the electric charge charged to the bypass capacitor when the power is turned on was discharged by the minute current consumed in the power supply circuit and the drive circuit of the device. Since time is required, the drive circuit may be damaged if the print head is detached during the discharge. FIG. 5 shows the configuration of this conventional print head drive control system. Hereinafter, an example of a conventional print head drive control system will be described with reference to the drawings. In order to solve this problem, there is a device in which a discharging resistor is provided in order to shorten the charge discharging time of the bypass capacitor. This configuration is shown in FIG. However, since the discharge resistor is always connected to the power supply, it consumes useless power. Further, in order to shorten the discharge time, it is necessary to reduce the resistance, so that it is necessary to increase the output capacity of the power supply, and there is a problem that the cost is increased. The discharge resistor may be provided on the carriage. FIG. 7 shows that in order to improve the above problem, a switch circuit that can be turned ON / OFF by a control circuit is provided between the discharge resistor and the power supply, thereby suppressing wasteful power consumption. There is something.

[0003]

However, in the above-described conventional ink jet recording apparatus, there is a problem of an increase in cost due to the provision of a discharge resistor and a switch circuit therefor. SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and discharges the electric charge of a bypass capacitor when a power supply of a device is turned off without consuming unnecessary power or increasing the cost of the device. It is an object of the present invention to provide an ink jet recording apparatus capable of performing the recording in a short time.

[0004]

According to one aspect of the present invention, there is provided an ink jet recording apparatus for ejecting ink onto a recording medium, and a driving circuit for driving the print head. Is mounted on the carriage,
This carriage is an ink jet recording apparatus that moves a print head along a recording medium to perform printing on the recording medium, and includes a bypass capacitor inserted into a power supply line that supplies power to a drive circuit, and an operation of each unit of the apparatus. Control means for controlling, and a signal generating means for giving a predetermined signal to the control means, the control means, when receiving a predetermined signal from the signal generating means, to stop power supply to the drive circuit,
By driving the print head via the drive circuit,
The charge stored in the bypass capacitor is discharged.

In the above configuration, the signal generating means
When the predetermined signal is given to the control means, the control means stops the power supply to the drive circuit and drives the print head via the drive circuit to discharge the electric charge of the bypass capacitor. Therefore, the electric charge of the bypass capacitor can be discharged in a short time without requiring a discharge resistor or a switch circuit therefor. Further, since there is no discharge resistor and no switch circuit therefor, useless power is not consumed.

According to a second aspect of the present invention, there is provided the ink jet recording apparatus according to the first aspect, wherein the signal generating means controls the signal for turning on or off the power of the apparatus. A power switch provided to the control means, wherein the control means stops power supply to the drive circuit and drives the print head via the drive circuit when receiving a signal for turning off the apparatus from the signal generation means. Thus, after discharging the charge stored in the bypass capacitor, the power supply of the device is turned off.

In the above configuration, when a signal for turning on or off the power of the apparatus is given to the control means from the power switch, the control means stops power supply to the drive circuit before turning off the power of the apparatus. At the same time, the print head is driven via the drive circuit to discharge the charge stored in the bypass capacitor.

According to a third aspect of the present invention, there is provided an ink jet recording apparatus according to the first aspect, wherein the signal generating means is operated when the print head is to be detached. The head detachment switch means, wherein the control means, upon receiving a signal from the print head detachment switch means, stops supplying power to the drive circuit and drives the print head via the drive circuit, thereby bypassing. This is to discharge the charge stored in the capacitor. In the above configuration, when the print head is to be attached / detached, the control unit drives the print head via the drive circuit to discharge the charge of the bypass capacitor by operating the print head attachment / detachment switch. Therefore, it is possible to prevent the drive circuit from being destroyed when the print head is attached or detached.

According to a fourth aspect of the present invention, there is provided the ink jet recording apparatus according to the third aspect, wherein the control means is provided with a signal for restarting power supply to the drive circuit. Is further provided. In the above-mentioned configuration, the above-mentioned means supplies a signal for restarting power supply to the drive circuit to the control means, and after the attachment and detachment of the print head is completed, the apparatus is returned to a printable state.

According to a fifth aspect of the present invention, there is provided the ink jet recording apparatus according to any one of the first to fourth aspects, wherein the electric charge stored in the bypass capacitor is discharged. The driving of the print head is a flushing operation of the print head.

In the above configuration, since the flushing operation of the print head is performed as the drive of the print head for discharging the electric charge to the bypass capacitor, the print head is effectively used as a part of the recovery operation for the print head. Can be driven, so that useless operation of the print head can be eliminated. Further, since this flushing operation is performed only by the electric charge charged in the bypass capacitor, it can be performed without consuming the power from the power supply.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An ink jet recording apparatus according to one embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an internal mechanism of a printer 1 according to an embodiment of the present invention, and shows a printing mechanism, a paper feeding mechanism, a purge device, and the like. The printing mechanism 2
The head unit 6 includes an ink jet print head 5, an ink cartridge 7 that supplies ink to the print head 5, and the like. The head unit 6 and the ink cartridge 7 are mounted on a carriage 8. here,
The carriage 8 is connected to the carriage motor 1 via a belt 9.
0, and moves horizontally along the carriage shaft 11. The print head 5 has a plurality of nozzles, and ejects ink from the nozzles in accordance with the movement of the carriage 8.

The paper feed mechanism 3 moves the print paper supplied from a paper feed cassette or a manual paper feed unit while facing the print head 5, and includes a platen roller 12, a pressure roller 13, and a line (not shown). It is composed of a feed (LF) motor and the like. Printing paper supplied from a paper cassette or the like is pressed and held by the platen roller 12 and the pressure roller 13 and is moved in accordance with the rotation of the line feed motor.

The purging device (suction means) 4 eliminates the occurrence of air bubbles inside the print head 5 during use and the occurrence of ink ejection failure due to ink droplets adhering to the ejection surface, and is preferable. This is a device for restoring to a proper ejection state. A cap 14 is provided at the tip of the purge device 4. When the cap 14 covers the print head 5, a negative pressure is generated by a pump to
The print head 5 is recovered by sucking the defective ink inside the print head 5. The flushing ink absorber 15 for flushing
Is used to keep the nozzles of the print head 5 in a good state and to absorb ink ejected by flushing, and is arranged outside the print area.

The printing mechanism 2 will be described in detail with reference to FIG. FIG. 2 is a schematic side view showing the printing mechanism 2. As described above, the head unit 6 having the print head 5 and the ink cartridge 7 are mounted on the carriage 8. The ink cartridge 7 is fixed to the head unit 6 and the carriage 8, and is fixed to the head unit 6 via a packing 17. The ink is supplied from the ink cartridge 7 to the print head 5 through the ink supply port 16. A substrate 1 for controlling the operation of the print head 5 is provided below the head unit 6.
8 are provided. A drive circuit (described later) having a circuit pattern for driving the print head 5 and a plurality of contacts 19 are provided on the substrate 18. The carriage 8 has an FPC (flexible printing circuit) 20 with dimple contacts and an FPC 2
A backup rubber 22 is provided for bringing the zero contact into contact with the contact 19 of the substrate 18. The board 18 and the print head 5 are connected by the FPC 21.

A guide shaft hole 8a for supporting the carriage 8 on the carriage shaft 11 is provided at a lower portion of the carriage 8 on the recording medium side. In order to keep the constant, the lower portion of the carriage 8 is
(See FIG. 1).

Next, a drive control system of the print head 5 will be described with reference to FIG. FIG. 3 is a schematic block diagram showing a control system of the printing mechanism 2. As described above, the carriage 8 is provided with the print head 5 and the drive circuit 31 formed on the substrate 18 for driving the print head 5.
The drive circuit 31 has a control circuit 3 for controlling the entire printer 1 via the FPC 20 and the contact 19 (see FIG. 2).
2 sends a command for controlling the operation of the print head 5,
Also, a power supply circuit 33 is connected. The drive circuit 31 drives the print head 5 via the FPC 21 (see FIG. 2) based on this command. A bypass capacitor 35 is connected to a power supply line 33 between the power supply circuit 33 that supplies power to the control circuit 32 and the drive circuit 31 and the drive circuit 31. The bypass capacitor 35 is disposed in the vicinity of the drive circuit 31, charges electric charge when the power supply circuit 33 is turned on, and causes the drive circuit 31 to function normally. The control circuit 32 is connected to a switch 36 that supplies various signals to the control circuit 32.

The switch 36 includes a power switch 36a for turning on / off the power of the entire printer 1, a switch 36b operated when the print head 5 is attached / detached, and a switch 36c operated for resuming printing after the attachment / detachment. Online switch 36 for switching between online and offline
d and the like. The switches 36a and 36b constitute signal generating means of the present invention. The control circuit 32 uses a known C
The print head 5 includes a PU, a ROM, a RAM, and a hardware logic circuit, and controls a line feed motor, a carriage motor 10, and the like. The power supply circuit 33 includes a line feed motor and a carriage motor 10.
Also supply power.

FIG. 4 is a flowchart showing a schematic operation of the control circuit 32. The control circuit 32 turns on the power switch 36a (S1: Yes),
b turns off (S6: No) and the online switch 36d
Is turned on (S12: Yes), and after waiting for data reception (S13), the print head 5, the line feed motor, the carriage motor 10 and the like are driven to execute a printing operation as is well known.

Next, by operating the power switch 36a,
The operation of the drive control system of the print head 5 when the power of the entire printer is turned off will be described. Power switch 36a
Is turned off (S1: No), the switch sends a signal to the control circuit 32 to turn off the power of the entire printer. The control circuit 32 controls the power supply circuit 3 based on this signal.
3 to stop the supply of power to the drive circuit 31 (S2). The power supply to the other parts, particularly to the carriage motor 10, is not stopped. Next, the control circuit 32
The carriage motor 10 is driven to move the print head 5 to a position facing the flushing ink absorber 15 (S3), and a drive signal is output to the drive circuit 31 to store the electric charge stored in the bypass capacitor 35. As a result, the print head 5 is driven to eject ink toward the absorber 15. That is, a flushing operation is performed (S4). This flushing operation is set so as to end when the electric charge of the bypass capacitor 35 is completely discharged. After discharging the electric charge of the bypass capacitor 35 in this way, the control circuit 32 returns the carriage 8 to the home position, and covers the print head 5 with a cap (not shown) (S4).
a) Output a signal to the power supply circuit 33 to turn off the power supply of the entire printer.

When the user intends to detach the print head 5 from the carriage 8 to replace the print head 5, the detach switch 36b is turned on (S6: Ye).
s), the control circuit 32 outputs to the power supply circuit 33 a signal for turning off only the power supply to the drive circuit 31 while keeping the power supply of the entire printer on (S7). Then, the control circuit 32 executes S8 and S9 in the same manner as S3 and S4 described above.
To perform a flushing operation. Then, the carriage 8
Is moved to the replacement position of the print head 5 (S9). At this position, the user replaces the print head 5 and turns on the restart switch 36c (S11).
Is returned to the home position (S11a), and the print head 5
Is covered with a cap, the control circuit 32 outputs a signal to start supplying power to the drive circuit 32 again to the power supply circuit 33. If the power supply circuit 33 is online, (S1: Yes, S6:
No, S12: Yes) Return to a printable state.
In this case, the print head 5 is replaced with the restart switch 36c.
The power supply to the drive circuit 32 can be restarted by detecting the attachment / detachment by the sensor.

As described above, in the printer 1 of the present embodiment, when the control circuit 32 receives a signal for turning off the power of the entire printer 1 from the power switch 36a, the power supply 33
Then, the supply of power to the drive circuit 31 is stopped, and then the print head 5 is caused to perform a flushing operation via the drive circuit 31, thereby discharging the charged charges in the bypass capacitor 35. Therefore, the discharge can be performed in a short time without a discharge resistor or a switch circuit for the discharge resistor, and wasteful power can be consumed as in the case of using the discharge resistor. Disappears. Further, since the electric charge of the bypass capacitor 35 is discharged, the print head 5 is caused to perform the flushing operation only by the electric charge of the bypass capacitor 35 without using the electric power of the power supply 33. Power consumption can be reduced.

Further, when the control circuit 32 receives a print head detachment signal from the detachment switch 36b while the power of the entire printer 1 is on, the control circuit 32 drives the printer 1 while keeping the power of the entire printer 1 on. Only the supply of the power of the power supply 33 to the circuit 32 is stopped, the flushing operation is performed by the print head 5, and the electric charge of the bypass capacitor 35 is discharged. Therefore, when the replacement of the print head 5 is completed thereafter, the printer 1 can be returned to a printable state only by starting to supply the power of the power supply 33 to the drive circuit 32 again. The time required to return to a normal state can be reduced.

The present invention is not limited to the configuration of the above embodiment, and various modifications are possible. For example, in the above embodiment, a predetermined signal is input to the control circuit 32 based on the operation of the switches 36a and 36b by the user, but when the print head is detached for replacement. Alternatively, a signal equivalent to the predetermined signal may be input to the control circuit 32. Further, a configuration may be adopted in which a signal equivalent to the above-described predetermined signal is input to the control circuit 32 when the cover for opening and closing the internal mechanism of the printer is opened and when an error occurs. Further, in the embodiment, the case where the print head 5 is detachable from the carriage 8 is described. However, the present invention is also applicable to a configuration in which the print head 5 cannot be detached from the carriage 8. In the above embodiment, the bypass capacitor 35 is provided on the carriage 8 together with the drive circuit 31 and the print head 5. May not be provided.

[0025]

As described above, according to the ink jet recording apparatus of the first aspect, the control means stops the supply of power from the power supply to the drive circuit, and controls the print head via the drive circuit. When driven, the electric charge of the bypass capacitor is discharged, so that the electric charge of the bypass capacitor can be discharged in a short time without the need for a discharging resistor or a switch circuit therefor. Will not be consumed. Furthermore, the cost can be reduced because a resistor for discharge and a switch circuit for the resistor are not required.

According to the second aspect of the present invention, when a signal for turning on or off the power supply of the apparatus is given to the control means from the switch means, the control means sends a signal to the drive circuit. With the power supply stopped,
By driving the print head via the drive circuit,
After the electric charge charged in the bypass capacitor is discharged, the power supply of the device is turned off. Therefore, the operation of turning off the power supply can discharge the electric charge of the bypass capacitor.

According to the third aspect of the present invention, when the print head is to be attached or detached, the control means stops the supply of power from the power supply to the drive circuit. After the print head is driven to discharge the charge of the bypass capacitor via the power supply, the supply of power from the power supply to the drive circuit is started again. Therefore, it is possible to prevent the drive circuit from being destroyed when the print head is attached or detached.

According to the fourth aspect of the present invention, a signal for restarting the power supply to the drive circuit is provided to the control means after the attachment / detachment of the print head is completed. Since the apparatus can be returned to a printable state only by starting the supply of the print data, the time required to return the apparatus to a printable state can be reduced.

According to the ink jet recording apparatus of the present invention, the drive of the print head for discharging the electric charge of the bypass capacitor is performed by the flushing operation which is a part of the recovery operation for the print head. Therefore, the print head does not move unnecessarily. Further, since this flushing operation is performed only by the electric charges charged in the bypass capacitor, the electric power from the power supply is not consumed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an internal mechanism of a printer according to an embodiment of the present invention.

FIG. 2 is a schematic side view showing a printing mechanism of the printer.

FIG. 3 is a schematic block diagram showing a control system of the printing mechanism.

FIG. 4 is a flowchart illustrating a schematic operation of a control circuit provided in the printer.

FIG. 5 is a schematic block diagram showing a print head drive control system having a conventional configuration in which electric charge of a bypass capacitor is discharged by a small current consumed by a power supply circuit and a drive circuit.

FIG. 6 is a schematic block diagram showing a conventional print head drive control system provided with a discharge resistor.

FIG. 7 is a schematic block diagram showing a printhead drive control system of a conventional configuration provided with a discharge resistor and a switch circuit therefor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printer 2 Printing mechanism 5 Print head 6 Head unit 7 Ink cartridge 8 Carriage 20 FPC 31 Drive circuit 32 Control circuit 33 Power supply circuit 34 Power supply line 35 Bypass capacitor 36 Switch

Claims (5)

(57) [Claims] A print head for ejecting ink to a recording medium and a drive circuit for driving the print head are mounted on a carriage, and the carriage moves the print head along the recording medium to print on the recording medium. In the ink jet recording apparatus, a bypass capacitor inserted into a power supply line for supplying power to the drive circuit, control means for controlling the operation of each unit of the apparatus, and signal generation means for giving a predetermined signal to the control means When the control unit receives a predetermined signal from the signal generation unit, the control unit stops supplying power to the drive circuit, and drives the print head via the drive circuit, so that the bypass capacitor An ink jet recording apparatus for discharging charged electric charges. 2. The power supply device according to claim 1, wherein the signal generation unit is a power switch that supplies a signal for turning on or off the power supply of the device to the control unit. When receiving the power, the power supply to the drive circuit is stopped, and the print head is driven through the drive circuit to discharge the electric charge stored in the bypass capacitor and then turn off the power supply of the apparatus. The ink jet recording apparatus according to claim 1, wherein: 3. The printing apparatus according to claim 2, wherein the signal generating unit is a print head detachable switch that is operated when the print head is detached, and the control unit receives a signal from the print head detachable switch. The power supply to the drive circuit is stopped, and the print head is driven via the drive circuit to discharge the electric charge stored in the bypass capacitor. The inkjet recording apparatus according to any one of the preceding claims. 4. The ink jet recording apparatus according to claim 3, further comprising: a means for supplying a signal for restarting power supply to the drive circuit to the control means. 5. The print head according to claim 1, wherein the drive of the print head for discharging the charge charged in the bypass capacitor is a flushing operation of the print head. Ink jet recording device.