JP3097494B2 - Inkjet printer - 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 printer for performing printing by scanning and moving a print head for ejecting ink with respect to a printing material.

[0002]

2. Description of the Related Art As is well known, an ink jet printer prints a desired image on a printing material by moving a printing head in a main scanning direction with respect to a printing material, for example, printing paper, and simultaneously moving a printing material in a sub-scanning direction. This ink jet printer is generally composed of a printer control unit composed of a computer or the like, and a printer mechanism unit whose operation is controlled by the printer control unit. The printer mechanism includes, for example, a print head, a drive system for scanning and moving the print head, and various other mechanisms.

In general, an ink jet printer is provided with an external operation switch for starting and stopping its operation. When the external operation switch is turned on, the printer operates and when the external operation switch is turned off. For example, the operation of the printer is stopped. Conventionally, as an ink jet printer provided with such an external operation switch, there is known an ink jet printer in which power supply to a printer control unit and a printer mechanism unit is immediately stopped when an external operation switch is turned off.

However, in the conventional ink jet printer of this type, when the external operation switch is turned off and the printer mechanism is in the middle of operation, the printer mechanism stops in the halfway state. Now, assuming, for example, a print head and its drive system as a printer mechanism, the print head must be located at a predetermined home position when printing is not performed and the printer is not operating. At this home position, for example, a process for constantly maintaining a head protection function such as capping an ink ejecting portion of a print head to prevent drying of the ink is performed. In a conventional inkjet printer in which the operation of the printer mechanism is immediately stopped when the external operation switch is turned off,
For example, if the external operation switch is turned off while the print head is performing a printing operation, the print head stops at a position other than the home position, and the print head may be damaged. In addition, similarly, various inconveniences may occur with respect to other components other than the print head constituting the printer mechanism.

[0005] In addition to the above-described conventional apparatus, there is also known a conventional ink jet printer in which a print head returns to a home position when an external operation switch is turned off. According to this printer, it is possible to prevent operating devices such as the print head from stopping at an intermediate position, so that damage to those operating devices can be prevented.

However, in this conventional ink jet printer, the print head or the like must be returned to the initial state after the external operation switch is turned off, so that the printer control unit is not turned off even after the external operation switch is turned off. And the power supply to the printer mechanism had to be continued without being stopped. In other words, the operation of switching the external operation switch to the OFF state means that the power of the ink jet printer is apparently turned off, and the power is substantially continuously supplied from the commercial power supply to the printer mechanism and the like. .
For this reason, the conventional ink jet printer of this type has a problem that power consumption is high and safety is low.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems in the conventional ink jet printer.
It is an object of the present invention to be able to reliably execute a post-processing operation on a printer mechanism including a print head after switching to a state, and to substantially stop power supply to the printer mechanism and the like.

[0008]

In order to achieve the above object, an ink jet printer according to the present invention is an ink jet printer in which the operation of a printer mechanism is controlled by a printer control unit. A transformer having a printer control section and a printer mechanism section on the secondary side; an AC generation switching transistor disposed on the primary side; and at least two of an ON state and an OFF state disposed on the secondary side. An external operation switch that takes two states, a delay circuit that outputs a signal after a predetermined time from when the external operation switch is turned off,
A power supply control unit for setting the switching transistor for AC generation to a non-switching state based on an output signal of the delay circuit, wherein when the external operation switch is turned off, the printer control unit performs a predetermined operation. After that, the supply power control unit switches the AC generation switching transistor to the non-switching state based on the output signal of the delay circuit to supply power to at least one of the printer control unit and the printer mechanism unit. Stop.

The above-mentioned printer mechanism is a mechanism including a print head, a drive system for the print head, a mechanism for capping the head, and various other operation systems. The printer control unit is a unit for controlling the operation of the printer mechanism unit.
It is composed of a computer including a PU (Central Processing Unit).

The ON state of the external operation switch means that
This is a state in which the operator has turned on the external operation switch to operate the inkjet printer. On the other hand, the OFF state of the external operation switch is a state when the operator switches the external operation switch to stop the operation of the inkjet printer. Generally, the external operation switch has at least two switching states, that is, a closed state and an open state, and the relation between the closed state and the open state and the above-mentioned ON state and OFF state is free depending on the circuit configuration to be adopted. Can be set to That is, the external operation switch can be set to an ON state when the external operation switch is closed, and set to an OFF state when the external operation switch is open. Alternatively, the external operation switch can be set to an ON state when the external operation switch is open and OFF when the external operation switch is closed. You can also set the status.

As a stabilized power supply used for a power supply unit of an ink jet printer, a transformer having a commercial power supply as a primary side and a printer control unit and a printer mechanism as a secondary side, and a transformer disposed on the primary side of the transformer. There is a so-called switching regulator type having a switching transistor for generating an alternating current. In this power supply, the power supply to the printer control unit and the printer mechanism is adjusted by controlling the switching operation of the switching transistor. When a power supply unit of this type is used, a supply power control unit for stopping power supply to the printer control unit and the printer mechanism unit can be configured, for example, in the following two ways.

The first configuration is as follows. A delay circuit is provided for outputting a signal after a predetermined delay time from when the external operation switch is turned off, and the switching transistor for AC generation is set to a non-switching state based on an output signal of the delay circuit. At the same time, the post-processing operation is executed by the printer control unit within the delay time.

The second configuration is as follows. A power supply stop switching element that performs a switching operation after completion of the post-processing operation by the printer control unit is provided. Then, the switching transistor for AC generation is set to a non-switching state based on the switching operation of the switching element.

When considering an ink jet printer of a type in which a switching transistor for AC generation is arranged on the primary side of a transformer, the supply power control unit includes a light emitting element and a primary side arranged on the secondary side of the transformer. Can be configured by using a photocoupler including a light receiving element arranged in the above. In the supply power control unit, the switching transistor for AC generation is set to the non-switching state based on the output signal of the light receiving element on the primary side.

[0015]

According to the ink jet printer of the present invention, when the external operation switch is switched to the OFF state, first, a post-processing operation is performed on the printer mechanism by the printer controller. For example, the print head is returned to the home position. Thereafter, after the completion of the processing operation, the supply of power to the printer mechanism and / or the printer controller is substantially stopped.

[0016]

【Example】

(Embodiment 1) FIG. 1 shows an embodiment of an ink jet printer according to the present invention. This inkjet printer has a power supply unit 1, a printer control unit 2, and a printer mechanism unit 3. The printer control unit 2 includes, for example, a computer. As shown in FIG. 2, the printer control unit 2 includes an arithmetic processing unit 4 that performs various printing operations and a memory 6 that stores predetermined programs for various printing operations. doing. Other components constituting the computer, such as an interface, are omitted for convenience. The printer mechanism 3 is a part including all of various operating devices constituting the ink jet printer, and includes, for example, pulleys 8a and 8 as shown in FIG.
b), a print head 7 connected to the timing belt 9, and a mechanism configured by a motor 10 for driving the timing belt 9.

The motor 10 is driven by a driver 11 whose operation is controlled by the arithmetic processing unit 4, and moves the timing belt 9 back and forth. When the timing belt 9 reciprocates in such a manner, the print head 7 connected to the timing belt 9 moves parallel to the printing material, for example, the printing paper 12, that is, moves in the main scanning direction, as shown by the arrow A. The print paper 12 moves in the sub-scanning direction in the direction of arrow B perpendicular to the main scanning direction A. Reference symbol H indicates the home position of the print head 7.

Returning to FIG. 1, the power supply section 1 has a rectifier circuit 15 composed of a diode bridge 13 and a capacitor 14 connected to a commercial power supply 16. A DC voltage is generated at both ends of the capacitor 14. Reference numeral 17 denotes a transformer, and the symbol “•” in the figure indicates the polarity of the winding of the transformer 17. Reference numeral 18 denotes a switching transistor for AC generation. In this embodiment, a field effect transistor is used. The a1 side of the primary winding 19a of the transformer 17 is connected to the anode of the capacitor 14, and its primary winding 19a
Is connected to the drain of the switching transistor 18 for AC generation. The source of transistor 18 is connected to the cathode of capacitor 14.

When the transistor 18 performs a switching operation that repeats energization and non-energization under the control of the drive circuit 20, an AC voltage is applied to the primary winding 19a and
An AC voltage is generated in the next winding 19c. The anode of the diode 21 is connected to the c2 side of the secondary winding 19c, and the c1 side of the winding 19c is connected to the cathode of the capacitor 22.
The anode of the capacitor 22 is connected to the cathode of the diode 21. The AC voltage generated in the winding 19c is rectified by the diode 21 and the capacitor 22,
A DC voltage is generated between the two terminals. Printer mechanism 3
Are connected to both ends of the capacitor 22 to receive supply of DC power.

The drive circuit 20 is connected to both ends of the capacitor 14, is connected to the gate of the switching transistor 18 for generating AC and the b1 side of the winding 19b, and supplies a drive voltage VG between the gate and the source of the transistor 18. To perform the switching operation of the transistor. A series circuit including a zener diode 23 and a resistor is connected to both ends of the capacitor 14, and a field effect transistor 24 is connected between the gate and the source of the switching transistor 18. The gate of the transistor 24 is connected to the emitter of the light receiving transistor 25b of the photocoupler 25, and the collector of the light receiving transistor 25b is connected to the cathode of the Zener diode 23. Photo coupler 25
Is the primary side of the high voltage transformer and the low voltage
It is electrically insulated from the next side.

The anode of the diode 26 is connected to the d2 side of the secondary winding 19d, the cathode of the capacitor 27 is connected to the d1 side of the winding 19d, and the anode of the capacitor 27 is connected to the cathode of the diode 26. Is done. When the primary side AC generation switching transistor 18 performs a switching operation, an AC voltage is generated in the winding 19d. The AC voltage is rectified by the diode 26 and the capacitor 27, and a DC voltage is generated across the capacitor 27. I do. A Zener diode 2 is connected to the anode of the capacitor 27 through a resistor.
The cathode of the capacitor 27 is connected to the anode of a zener diode 28. The cathode of the Zener diode 28 is connected to the anode of a capacitor 30 via a resistor 29, and the cathode of the capacitor 30 is connected to the anode of the Zener diode 28. Also, the capacitor 30
Is connected to the gate of the field effect transistor 31, and the cathode of the capacitor 30 is connected to the source of the transistor 31. The drain of the transistor 31 is connected to the cathode of the light emitting diode 25a of the photocoupler 25, and the anode of the light emitting diode 25a is connected to the secondary winding 1
It is connected to the anode of the capacitor 22 on the 9c side.

A switch 32b of the external operation switch 32 is arranged between the gate and the source of the transistor 31. The external operation switch 32 has another switch 32a that opens and closes simultaneously with the operation of the switch 32b. The external operation switch 32 according to the present embodiment is set to a closed state when the operator turns on the external operation switch in order to operate the inkjet printer, that is, when the operator is ON. On the other hand, the state when the operator switches the external operation switch to stop the operation of the inkjet printer, that is, the state when the operation is OFF
Set to open when in the state.

On the secondary winding 19c side, the capacitor 2
A regulator 33 that reduces the input DC voltage and outputs a low-voltage DC voltage is connected between both terminals of the printer 2, and the output voltage of the regulator 33 is supplied to the printer control unit 2. One switch 32a of the external operation switch 32 is
It is arranged between the output terminal of the regulator 33 and the source of the transistor 31. One terminal of the switch 32a is guided to the arithmetic processing unit 4 (FIG. 2) via the resistor 40 and the input terminal (A) of the printer control unit 2.

In the circuit configuration described above, the supply power control unit for stopping the power supply to the printer control unit and / or the printer mechanism unit includes the transistor 31, the photocoupler 25, and the transistor 24. In addition, a delay circuit that outputs a signal after a predetermined delay time from when the external operation switch 32 is turned off includes a zener diode 28, a resistor 29, a capacitor 30, and a transistor 31.

Hereinafter, the operation of the ink jet printer having the above configuration will be described with reference to a timing chart shown in FIG. In the following description, a state in which the operator operates the external operation switch to start the operation of the inkjet printer is referred to as an ON state, and a state in which the operator operates the external operation switch to stop the operation of the inkjet printer. Is expressed as an OFF state. In this embodiment, as described above, the switches 32a and 32b of the external operation switch 32 are in the ON state.
Is closed and each switch 32a is in the OFF state.
And 32b are set to be open.

In FIG. 3, the external operation switch 32 is
When in the N state (closed state), predetermined power is supplied to the printer control unit 2 and the printer mechanism unit 3 by the operation of the power supply unit 1 in FIG. . For example, in FIG. 2, the print paper 12 is transported in the direction of arrow B, and at the same time, the print head 7 is driven by the timing belt 9 to move in the direction of arrow A. During these movements, the print head 7 moves the paper 1 at a timing based on an appropriate print signal.
Ink is ejected toward the paper 2, whereby a desired image is obtained on the paper 12.

When the operator turns off the external operation switch 32 (opens) to stop the operation of the ink jet printer, the signal input terminal (A) of the printer control unit 2 becomes H (High), and the external operation switch 32 is turned off. The control unit 2 has switched to the OFF state (open state).
Is detected by Then, the arithmetic processing unit 4 (FIG. 2) in the printer control unit 2 executes a post-processing operation on the printer mechanism unit 3. The post-processing operation is an operation for returning the operation state of various devices constituting the printer mechanism unit 3 to the initial position. For example, the print head 7 (FIG. 2) that is scanning and moving is moved to the home position H. And the like.

The external operation switch 32, especially its contact 32
While the above-described post-processing operation is being performed after b is turned off (opened), the capacitor 30 is charged and the voltage between its terminals gradually increases. When this voltage exceeds the threshold voltage of the transistor 31, the gate of the field effect transistor 31 is turned on and the transistor 31 is turned on. As a result, the light emitting diode 25a of the photocoupler 25 is turned on and emits light. Due to this light emission, the light receiving transistor 25b is turned on, so that the gate of the field effect transistor 24 is turned on and the transistor 24 is turned on. Then, no bias voltage is applied between the gate and source of the switching transistor 18 for AC generation, and the switching operation by the transistor 18 stops or becomes insufficient. As a result, the DC voltage generated at both ends (C) of the capacitor 22 on the secondary side decreases, and the DC voltage generated at the output terminal of the regulator 33 also decreases at the same time. The supply of the DC power to the mechanism unit 3 is substantially stopped. Substantially stopping means that the supplied DC power may be exactly zero, or that a small amount of power of about several volts that does not affect the operation of the printer mechanism 3 or the like may flow. That is.

As described above, the external operation switch 32 is
When the state is switched to the FF state (open state), first, predetermined post-processing is performed on the printer mechanism unit 3 by the printer control unit 2. For example, in FIG. 2, when the print head 7 is performing a printing operation,
Is forcibly moved back to the home position H. At this home position H, a cap for covering the ink ejecting portion of the print head 7 is disposed. By covering the ink ejecting portion of the print head 7 which has returned to the home position H with the cap, the drying of the ink is prevented. Or to prevent the print head from being damaged. If necessary,
At the home position H, an additional process for constantly maintaining the performance of the print head is performed. Then, after such a post-processing operation is completed, power supply to the printer control unit and the printer mechanism unit is stopped. As a result, power saving and safety for the operator are ensured.

(Embodiment 2) FIG. 4 shows another embodiment of the ink jet printer according to the present invention. This embodiment is different from the previous embodiment shown in FIG. 1 in that a transistor 34 as a switching element for stopping power supply and a resistor Ra
, A resistor Rb and a diode D are connected to the output terminal (B) of the printer controller 2.
The other circuit elements are the same as those in the embodiment of FIG. 1, and the same elements are denoted by the same reference numerals and description thereof will be omitted.

In the embodiment shown in FIG. 1, the transistor 31 is turned on after the external operation switch 32 is turned off (opened) by the time constant formed by the Zener diode 28, the resistor 29 and the capacitor 30. The time until the power supply stops is determined. The delay time is set to be sufficiently long with respect to the post-processing operation time of the printer due to large variations. In particular,
The post-processing operation time is generally 10 to 20 seconds, whereas the delay time is set to about 1 to 2 minutes.

When the delay time is set to be long as described above, several tens of seconds are required between the end of the post-processing operation and the actual stop of the power. That is, in the printer according to the first embodiment, when the post-processing is completed, the power supply is apparently turned off by turning off the LED of the operation panel or the like. However, actually, the power is not consumed for several tens of seconds until the delay time elapses. Will be supplied. At this time, if the operator replaces, for example, an optional board such as an interface, there is a possibility that a circuit failure or a runaway of the carriage mounting the print head may occur. Example 2 is to avoid such a danger.
The power supply is stopped immediately after the completion of the post-processing operation for the printer mechanism.

In this embodiment, the transistor 34 is connected between the output terminal of the regulator 33 and the gate of the transistor 31 via the resistors Ra, Rb and the diode D. And the base of this transistor 34 is
As shown in FIG. 5, an output terminal (B) of the printer control unit 2
Through the arithmetic processing unit 4. The resistances Ra and Rb are set to sufficiently smaller resistance values than the resistance 29.

Also in this embodiment, when the operator turns off the external operation switch 32 (opens) in order to stop the operation of the ink jet printer, as shown in FIG. Becomes “H”, and the control unit 2 detects that the external operation switch 32 has been switched to the OFF state (open state). Then, the arithmetic processing unit 4 (FIG. 5) in the printer control unit 2 performs a post-processing operation on the printer mechanism unit 3, for example, an operation of returning the print head 7 to the home position H.

Thereafter, when the processing operation is completed, the arithmetic processing unit 4 switches the output of the output terminal (B) from "H" to "L" immediately according to a predetermined program, and switches the output of the transistor 34.
Is turned on. Then, a current rapidly flows to the capacitor 30 through the resistors Ra and Rb, which are sufficiently smaller than the resistor 29, and the capacitor is rapidly charged. As a result, the voltage between the terminals of the capacitor 30 is reduced in a very short time by the transistor 31. Threshold voltage, and as a result,
The transistor 31 is turned on. Then, the light emitting diode 25a of the photocoupler 25 is energized and emits light, and the light emission causes the light receiving transistor 25b to be energized. As a result, the gate of the field effect transistor 24 is energized and the transistor 24 is energized. Then, no bias voltage is applied between the gate and the source of the switching transistor 18 for AC generation, and the switching operation by the transistor 18 stops or becomes insufficient. As a result, the DC voltage generated at both ends (C) of the capacitor 22 on the secondary side decreases, and the DC voltage generated at the output terminal of the regulator 33 also decreases at the same time. The supply of the DC power to the mechanism unit 3 is substantially stopped.

As is clear from the above description, also in this embodiment, when the external operation switch 32 is switched to the OFF state (open state), first, post-processing relating to the printer mechanism 3 is executed, and thereafter the processing is completed. After that, the power supply to the printer control unit 2 and the printer mechanism unit 3 is stopped. The Zener voltage of the Zener diode 28 is set to 5
V, the resistance 29 is 470 kΩ, and the capacity of the capacitor 30 is 3
30 μF, the resistance Ra is 100Ω, and the resistance Rb is 10Ω.
If it is set to 0Ω, it takes about 79 seconds until the voltage between the terminals of the capacitor 30 reaches the threshold voltage of the transistor 31 unless the transistor 34 is turned on after the external operation switch 32 is turned off. However, when the transistor 34 is turned on, the voltage between the terminals of the capacitor 30 reaches the threshold voltage of the transistor 31 within approximately 0.03 seconds.

As described above, the present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to these embodiments, and can be variously modified within the technical scope described in the claims. For example, the post-processing to be performed on the printer mechanism 3 is not limited to the operation of returning the print head to the home position, but may be the operation of initializing various other devices.

[0038]

According to the ink jet printer of the present invention, the damage to the printer can be reliably prevented by executing the post-processing operation, and the power supply is stopped to reduce the power consumption and ensure the safety for the operator. Can be realized.

Further, according to the ink jet printer of the present invention, it is possible to stop the power supply without generating a useless delay time as compared with a case where only a delay circuit formed by a resistor, a capacitor and the like is used. .

[0040]

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of an ink jet printer according to the present invention.

FIG. 2 is a diagram schematically showing a main part of FIG. 1;

FIG. 3 is a timing chart showing an operation of a main part of the circuit diagram of FIG. 1;

FIG. 4 is a circuit diagram showing another embodiment of the ink jet printer according to the present invention.

FIG. 5 is a diagram schematically showing a main part of FIG. 4;

6 is a timing chart showing the operation of the main part of the circuit diagram of FIG.

[Explanation of symbols]

 Reference Signs List 1 power supply section 2 printer control section 3 printer mechanism section 7 print head 8a, 8b pulley 9 timing belt 10 motor 12 print paper 13 diode bridge 14, 22, 27, 30 capacitor 16 commercial power supply 17 transformer 18 switching transistor 19a, 19b, 19c, 19d Winding 20 Drive circuit 21, 26 Diode 23, 28 Zener diode 24, 31 Field effect transistor 32 External operation switch 34 Transistor

Continuation of the front page (56) References JP-A-7-15865 (JP, A) JP-A-4-220351 (JP, A) JP-A-63-154383 (JP, A) JP-A-2-84058 (JP, A) JP-A-4-289772 (JP, A) JP-A-7-274498 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 29/38 B41J 2/01

Claims (6)

(57) [Claims] 1. An ink jet printer in which the operation of a printer mechanism is controlled by a printer controller, wherein a commercial power supply is used as a primary side, and a printer is used as a printer controller and a printer mechanism as a secondary side. A switching transistor for AC generation arranged on the primary side; an external operation switch arranged on the secondary side in at least two states of an ON state and an OFF state; and a state in which the external operation switch is turned off. A delay circuit that outputs a signal after a predetermined time, and a supply power control unit that causes the AC generation switching transistor to be in a non-switching state based on an output signal of the delay circuit, wherein the external operation switch is turned off. Then, the printer control unit performs predetermined post-processing, and thereafter, the power supply control unit performs the delay An ink jet printer in which power supply to at least one of a printer control unit and a printer mechanism unit is stopped by setting the switching transistor for AC generation to a non-switching state based on an output signal of a path. 2. The image forming apparatus according to claim 1, further comprising: a power supply stop switching element that operates when the post-processing is completed. When the external operation switch is turned off, the printer control unit performs the post-processing, When a signal of the power supply stop switching element is output prior to the output signal, the supply power control unit sets the AC generation switching transistor to a non-switching state based on an output signal of the power supply stop switching element. The inkjet printer according to claim 1, wherein: 3. A light-emitting element that emits light based on an output signal of a delay circuit or an output signal of a switching element for stopping power supply, and a light-receiving element that receives light from the light-emitting element and outputs a signal. The inkjet printer according to claim 1, further comprising a photocoupler including an element, and wherein the AC generation switching transistor is turned off based on an output signal of the light receiving element. 4. The ink jet printer according to claim 1, wherein the predetermined post-processing includes a series of operations for constantly maintaining the performance of the print head of the printer mechanism. Printer. 5. A transformer having a commercial power supply as a primary side, a printer control section and a printer mechanism section as a secondary side, an AC generation switching transistor disposed on the primary side, and a transformer on the secondary side. An external operation switch that takes at least two states of an ON state and an OFF state,
A method for controlling an operation of a printer mechanism unit by a printer control unit disposed on the secondary side in an ink jet printer, comprising: a step of detecting that the external operation switch is turned off; A step in which the printer control unit performs predetermined post-processing after the external operation switch is turned off; and a predetermined time after the external operation switch is turned off after the predetermined post-processing by the printer control unit. A step of outputting a delay signal, and a step of stopping power supply to at least one of a printer control unit and a printer mechanism unit by setting the switching transistor for AC generation to a non-switching state based on the output of the delay signal. Control method for an inkjet printer having 6. The inkjet printer further includes a power supply stop switching element that operates when the post-processing is completed, and when the signal of the power supply stop switching element is output prior to the output of the delay signal, The method further includes a step of stopping power supply to at least one of a printer control unit and a printer mechanism unit by setting the switching transistor for AC generation to a non-switching state based on an output signal of the switching element for power supply stop. The control method for an ink jet printer according to claim 5, wherein