JPH09234879A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an ink discharge capability from being deteriorated by performing maintenance services such as capping even when a power supply to a printer is shut off. SOLUTION: A battery B is charged by a power supply +V connected to a printer, and if the power supply +V is shut off, a voltage Vsc for a maintenance signal to be output from CPU stands at a high level, then a transistor Tr is set in the ON state, and the current from the battery B is supplied as a drive voltage Vct to a circuit for operating a maintenance mechanism through the transistor Tr, so that maintenance services are executed.

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 that ejects ink droplets from nozzles to record on a recording medium, and is capable of performing capping or the like even when power supply is cut off due to a power failure or the like. The present invention relates to a device suitable for performing a maintenance operation.

[0002]

2. Description of the Related Art An ink jet printer (hereinafter abbreviated as a printer) is a nozzle for ejecting ink droplets from a nozzle of an ink jet head (hereinafter abbreviated as a head) to perform recording on a recording medium. If the ink is clogged with dust or the ink is solidified, the ink ejection performance deteriorates. Therefore, the printer is provided with a capping mechanism (capping) that covers the nozzle forming surface of the head. The capping mechanism turns off the drive power switch of the printer when the head is not used for a certain period of time or more. In this case, the printer is operated by the power supply supplied to the printer.

[0003]

However, in the above-mentioned prior art, since the maintenance mechanism is operated by the power supplied to the printer, when the power supply to the printer is interrupted due to a power failure or the like. Has a problem that the capping mechanism cannot be operated. In other words, the nozzle may become clogged with dust, etc. before the power is restored,
There is a problem that the ink ejection performance may deteriorate due to solidification of the ink.

Therefore, the present invention provides a printer capable of preventing deterioration of ink ejection performance by operating a maintenance mechanism such as a capping mechanism even when power supply to the printer is cut off. With the goal.

[0005]

In order to achieve the above object, the present invention provides an ink jet head for recording on a recording medium by discharging ink droplets from a nozzle in the invention described in claim 1. In inkjet printers,
A maintenance mechanism having a cap member capable of covering the nozzle forming surface of the inkjet head, a detection unit for detecting disconnection of power supplied to the apparatus, a standby power supply unit, and a disconnection of power detected by the detection unit. In this case, a technical means is provided that includes a maintenance control means that drives the maintenance mechanism by the standby power supply means and executes a capping process for covering at least the nozzle forming surface of the inkjet head with the cap member.

According to a second aspect of the invention, in the ink jet printer according to the first aspect, the ink jet head performs recording by ejecting ink droplets while scanning the recording medium. The maintenance mechanism, in the scanning area of the inkjet head,
The inkjet head is arranged at a position outside the area for performing recording on the recording medium, and the maintenance control means controls the standby power source means to operate the inkjet head when the disconnection of the power source is detected by the detection means. A technical means of moving the maintenance mechanism to a position where the maintenance mechanism is arranged and executing the capping process at the position is adopted.

According to a third aspect of the present invention, in the ink jet printer according to the first or second aspect, the maintenance mechanism has a wiper means for cleaning a nozzle forming surface of the ink jet head, and the maintenance control means comprises: Before performing the capping process, a technical means of performing a wiping process for cleaning the nozzle forming surface of the inkjet head by the wiper means is adopted.

According to a fourth aspect of the present invention, in the ink jet printer according to any one of the first to third aspects, the auxiliary power source means is provided with a charger, and the charger is normally used. The technical means of being charged by the device power supply is adopted.

According to a fifth aspect of the invention, in the ink jet printer according to the fourth aspect, the capping process is performed on the charger from when the power source is turned on until the ink jet head is driven. Adopting the technical means that sufficient power is charged to run the.

According to a sixth aspect of the present invention, the first aspect
In the ink jet printer according to any one of 1 to 5, when the detection unit detects disconnection of the power source during the printing operation, the standby power source unit ejects the recording medium in the middle of recording to the outside of the apparatus. The technical means of providing a paper discharge means for performing the processing is adopted.

[0011]

According to the invention described in claims 1 to 6, the detecting means for detecting the disconnection of the power supply to the apparatus, the standby power supply means, and the maintenance mechanism when the disconnection of the power supply is detected by the detecting means. And a maintenance control means for executing at least a capping process for covering at least the nozzle forming surface of the ink jet head with the cap member, so that the nozzle forming surface is covered even when the power to the printer is cut off. You can Therefore, it is possible to prevent the nozzles from being clogged and the ink to be solidified before the power is restored, so that there is no fear of deterioration of the ink ejection performance. That is, even after the power is restored, printing can be performed with the same quality as before the power supply was cut off.

Particularly, in the invention described in claim 2,
In an inkjet printer equipped with an inkjet head that performs recording by ejecting ink droplets while scanning on a recording medium, when the power is cut off, the head is moved to a maintenance mechanism fixed at a predetermined position other than the scanning area. After this, capping processing is performed. Therefore, when the power is turned on again to start printing, the head is always at the fixed position, which is the maintenance position, and therefore, the head can be quickly returned to the end portion of the printing area and printing can be executed.

Further, in the invention according to claim 3, the maintenance mechanism has a wiper means for cleaning the nozzle forming surface of the ink jet head, and the maintenance control means has the wiper means before performing the capping process. Since the wiping process for cleaning the nozzle forming surface of the inkjet head by the means can be performed, it is possible to cover the nozzle forming surface with the cap member after cleaning the nozzle forming surface. Therefore, it is possible to prevent the ink adhering to the vicinity of the outlet of the nozzle from being solidified and the ink ejection performance from being deteriorated before the power is restored.

Further, in the invention described in claim 4, the auxiliary power source means is provided with a charger, and since this charger is normally charged by the device power source, a special charging operation is performed. There is no need to do it.

Further, in the invention described in claim 5, the charging body is charged with sufficient electric power for executing the capping process before the ink jet head is driven by turning on the power supply. In other words, since the charging body is sufficiently charged before the inkjet head is removed from the capping position for performing the printing operation, the head can be reliably capped even when the power is cut off immediately after the start of printing. It will be possible.

Further, in the invention described in claim 6, when the detection means detects the disconnection of the power source during the printing operation, the standby power source means ejects the recording medium in the middle of recording out of the apparatus. Since the sheet ejecting unit for performing the processing is provided, it is possible to prevent the recording medium from being unable to be ejected due to the disconnection of the power source.

[0017]

DETAILED DESCRIPTION OF THE INVENTION A printer according to a first embodiment of the present invention will be described below with reference to the drawings. Figure 1 is the first book
FIG. 2 is an explanatory diagram showing the main structure of the printer of the embodiment, and FIG. 2 is a block diagram showing its control system. In each of the embodiments described below, a color printer that performs color printing as a representative of a printer, pressurizes an ink chamber by a piezoelectric effect of a piezoelectric element, and ejects ink in the ink chamber from a nozzle to perform printing. What will be done will be explained as a representative.

As shown in FIG. 1, the printer 10 is provided with a platen 12 on which printing paper, which is a recording medium, is loaded. The platen 12 is connected to an LF motor (paper feed motor) 58. It is rotated by the paper feeding mechanism 62 (see FIG. 2). At the position facing the platen 12,
A head (printing head) 20 is provided, and the head 20 is mounted on a carriage 21. A guide shaft 14 mounted in the width direction of the printer 10 is inserted through a lower front portion of the carriage 21, and a lower rear portion is slidably supported on a rail 16.

Further, the carriage 21 is connected to an endless belt 30 which is wound around a CR motor (carriage moving motor) 18. That is, the head 20 is CR
By the rotation of the motor 18, the guide shaft 14 and the rail 1
It reciprocates on the plate 6 facing the platen 12. In addition, LF
A step motor is used as the motor 58, and a DC motor whose rotation speed is controlled by PWM control is used as the CR motor 18. The head 20, the LF motor 58, and the CR motor 18 are driven by a power source supplied from a power source 40.

To the head 20, a black head 22 for ejecting black ink, a yellow head 23 for ejecting yellow ink, a cyan head 24 for ejecting cyan ink, and a magenta ink are ejected. And a magenta head 25. Each head is provided with a plurality of ink chambers (not shown) for accommodating ink, and the surface (nozzle formation surface) of each of the ink chambers facing the platen 12 is a nozzle for ejecting ink in the ink chamber. Are formed respectively. A piezoelectric element is provided in each ink chamber, and by applying a drive voltage to the piezoelectric element, the volume of the ink chamber changes and the ink in the ink chamber is pressurized, and the ink is printed from the nozzles. The ink is ejected toward the paper and printing is performed.

Below the guide shaft 14, there is provided a linear timing slit (not shown) in which 90 slits are marked in one inch. A sensor element (not shown) that reads the interval of the slits marked on the timing slits and outputs a pulse signal corresponding to the position of the carriage 21 is provided. The timing slit and the sensor element form the encoder 55 (see FIG. 2).

The printer 10 is equipped with several maintenance mechanisms for performing high quality printing.
As one of them, there is provided a flushing function for periodically ejecting defective ink containing bubbles to maintain a good printing state, and the head 20 is located at a position outside the printing region at the left end in the moving direction of the head 20. An ink absorber 32 that absorbs the ink ejected from the nozzles when the flushing is performed is provided.

Further, in the printer 10, a purging mechanism 34 (refer to FIG. 2) which sucks dry ink, foreign matters, etc. clogged in the nozzles at regular intervals to maintain a good ink discharge state.
And a suction cap 34a is provided on the right side in the moving direction of the head 20 to cover the head for purging at a position outside the printing area. This suction cap 34a advances toward the nozzle forming surface of the head that performs purging in conjunction with this when the head 20 moves to the purging position on the right side out of the printing area, Put on the lid. And
By driving the pump 34b connected to the cap 34a, the defective ink is sucked from the nozzle of the head forming surface covered with the suction cap 34a. The purging mechanism 34 is driven by the LF motor 58 to switch the switching mechanism 61.
(See FIG. 2).

Further, in the printer 10, when the head 20 is not used for a certain period of time, when the power switch of the printer is turned off, or when the power supply to the printer 10 is cut off due to a power failure or the like, Head 22
A capping mechanism 35 (see FIG. 2) for covering the nozzle forming surfaces of Nos. 25 through 25 is provided. Suction cap 34
A cap member 35a is provided on the right side of a,
The cap member 35a is advanced toward the nozzle forming surface of the head 20 when the head 20 is moved out of the printing area and further moved to the right capping position. It should be noted that the cap member 35a is moved forward and backward through the switching mechanism 61 (see FIG. 2) by driving the LF motor 58.

Further, the printer 20 includes a head 20.
A wiping mechanism 33 (see FIG. 2) for wiping and cleaning the ink adhering to the nozzle forming surface is provided, and a wiper member 33a as a wiper means for wiping is provided on the left side of the suction cap 34a. The wiper member 33a is adapted to move forward and backward with respect to the nozzle forming surface via the switching mechanism 61 (see FIG. 2) by the driving of the LF motor 58, and normally, when purging of the head 20 is completed, The head 20 advances toward the nozzle formation surface. Then, the head 20 is moved in the print area direction while the wiper member 33a is in contact with the nozzle forming surface, and the movement causes the wiper member 33a to wipe the nozzle forming surface. On the other hand, in an emergency such as a power failure, the nozzle forming surface is wiped by the wiper member 33a before the head 20 reaches the capping position, as described later.

Next, the main configuration of the control system of the printer will be described with reference to FIG. The printer 10 includes a CPU 50 that performs various types of arithmetic processing described below. The CPU 50 has an interface 52 for receiving signals such as print data output from the host computer 51, a control circuit 70 for operating the maintenance mechanism when power supply is stopped due to a power failure or the like.
Is connected. Further, the ROM 53 and the RAM 5 in which a control program for operating the control circuit 70 and a print program for driving the head 20 to print are stored.
4. A gate array 56 for connecting the encoder signal output from the encoder 55 and calculating the position of the carriage 21 is connected.

The CPU 50 stores the print data received from the host computer 51 via the interface 52 in a predetermined area of the RAM 54, and in accordance with the print program stored in the ROM 53 in advance, the LF motor 58 and the CR motor. 18 and head 20
It outputs various control signals for driving the. Then, of the control signals, L for driving the LF motor 58
The F motor drive control signal is input to the LF drive circuit 57, and the LF motor 58 is driven according to the LF motor drive signal output from the LF drive circuit 57. That is,
By driving the LF motor 58, the printing paper is fed in the vertical direction.

Of the above control signals, the CR motor 1
The CR motor drive control signal for driving 8 is input to the CR drive circuit 59, and the CR motor 18 is driven according to the CR motor drive signal output from the CR drive circuit 59. The carriage 21 is reciprocated by driving the CR motor 18, and the position of the carriage 21 is detected by the encoder 55. Then, the encoder signal output from the encoder 55 is input to the gate array 56, and based on the input encoder signal, the gate array 56 outputs a velocity data signal of the carriage 21 and a position control pulse (reference value) of the carriage 21. Pulse), a print timing pulse for driving the head 20, and the like.

Then, the CPU 50 uses the gate array 56.
The speed data (time interval value between each edge of the encoder signal) output from is input and the PWM signal (pulse width of the drive signal of the CR motor 18) required for speed control of the carriage 21 is calculated. Further, a position control pulse (reference pulse) is input to calculate the current position of the carriage.
Further, the CPU 50 performs a control operation such as writing a delay count value for matching the print positions when the printing direction is reversed and data for permitting the print start signal to a register in the gate array 56.

Of the control signals output from the CPU 50, the head drive control signal for driving the head 20 created based on the print data is the head drive circuit 60.
The head 20 is driven in accordance with the head drive signal input to the head drive circuit 60 and output from the head drive circuit 60. That is, when the head drive signal is input to the head 20,
A voltage is applied to the piezoelectric element forming each element of each head, the vibration plate of the ink chamber provided with the piezoelectric element is displaced, and the ink in the ink chamber is pressurized and ejected from the nozzle.

Further, the CPU 50 counts the pulse signals which are the drive signals of the LF motor 58, and the LF motor 5
8 and the paper feed mechanism 62 count the feed amount of the printing paper and the rotation amount of the cam that drives the purging mechanism 34 or the capping mechanism 35. In addition, the capping mechanism 35 includes a carriage 2
The HP (home position) sensor 63 that detects that 1 has returned to the capping position (home position) and the PE (paper empty) sensor that detects the insertion or discharge of the printing paper in the paper feeding mechanism 62. 64 are provided respectively.

Next, the control circuit 7 connected to the CPU 50
The operation of 0 will be described with reference to FIGS. 3 and 4.
FIG. 3 is a circuit diagram showing the control circuit 70, and FIG.
It is an explanatory view of an input / output port of PU50. In FIG. 3, + V is a power supply supplied from the power supply 40, V _m is a main power supply supplied to the CPU 50 via the diode D2, and V _b is a backup power supply of the CPU 50 supplied via the resistor R1. , V _SC is a signal voltage appearing at the output port of the CPU 50 for outputting the maintenance signal, V _SC
CL indicates the drive voltage supplied to the LF drive circuit 57 and the CR drive circuit 59, respectively.

The control circuit 70 includes a printer 1 for a power failure or the like.
A battery B is provided as a charger for operating the capping mechanism 35 when the power supply to 0 is cut off. In the battery B, the power switch SW of the printer is turned on so that the printer 10 receives the main power _Vm.
Power is supplied via diode D1
Charged by V. The signal voltage V _SC of the maintenance signal output from the CPU 50 is at the Low level except when the power supply is cut off in an emergency, so the base current to the transistor Tr via the resistor R1 is lower than the operating current. It is small and the transistor Tr is in the OFF state. That is, the drive voltage V _CL is not supplied to the drive circuits.

Next, the control circuit 70 by the CPU 50.
The control will be described with reference to the flowchart of FIG. During use of the printer 10, due to a power failure or the like,
When the supply of the power supply + V to the printer is cut off, the main power supply V _m becomes the Low level, so that the CPU 50 causes the power supply + V
It is detected that the supply of V has been cut off (step 10
0), the voltage V _{SC of the} maintenance signal output from the output port becomes High level (step 110). As a result, the transistor Tr is turned on, the current of the battery B flows through the transistor Tr, and the drive voltage V _CL is supplied.

Then, a CR motor drive command is issued to the CR drive circuit 59 (step 120), and the carriage 21 is moved to the capping position by driving the CR motor 18. Then, the HP sensor 63 detects that the carriage 21 has reached the capping position (step 130), and a capping mechanism operation command is issued to the LF drive circuit 57 (step 140). Then, the operation of the LF drive circuit 57 causes the LF motor 58 to move.
Is driven, and the switching mechanism 61 is switched to the capping mechanism 35. Subsequently, the capping mechanism 35 is driven, and the cap members 35a are covered on the nozzle forming surfaces of the heads 22 to 25.

When the end of capping is detected by counting the amount of rotation of the cam driving the capping mechanism 35 (step 150), the voltage V _{SC of the} maintenance signal changes to low level (step 160),
The transistor Tr is turned off, and the power supply to the battery B is stopped. Thus, according to the printer of the present embodiment, even when the power supply to the printer is cut off,
Since the head 20 can be moved to the capping position and capping can be performed by the battery provided in the control circuit, the nozzles of the head 20 are clogged or ink is solidified and ejection failure occurs before the power is restored. Can be prevented.

Next, a printer according to the second embodiment of the present invention will be described with reference to the flowchart of FIG. The printer of the second embodiment is characterized in that wiping is performed before capping. Main power supply V _m is Lo
When it is detected that the w level is reached (step 10
0), the voltage V _{SC of the} maintenance signal becomes High level (step 110), and the drive voltage V _SC is driven by the battery B.
_CL is supplied.

Then, a CR motor drive command is issued (step 120), movement of the carriage 21 toward the home position is started, and a wiping mechanism operation command is issued (step 122) to drive the LF motor 58. As a result, the wiping mechanism 33 is operated via the switching mechanism 61 (see FIG. 2), and the wiper member 33a moves forward with respect to the nozzle forming surface. Then, the carriage 21 is moved toward the home position in a state where the wiper member 33a is in contact with the nozzle forming surface, and this movement causes the wiper member 33 to move.
The nozzle forming surface of the head 20 is wiped by a.

Subsequently, when the carriage 21 is detected by the HP sensor 63 (step 130), a capping mechanism operation command is issued (step 140), and the capping mechanism 35 causes the cap member 35a to move to each head 2.
2 to 25 nozzle forming surfaces are covered. When the end of capping is detected (step 150),
The voltage V _{SC of the} maintenance signal changes to the low level (step 160), the transistor Tr is turned off, and the power supply of the battery B is stopped. As described above, according to the printer of the second embodiment, even if the power supply to the printer is cut off, the battery provided in the control circuit can perform the wiping before the capping. It is possible to wipe and clean the nozzle forming surface of the head 20. Therefore, it is possible to prevent deviation of the flight path of the ink droplet due to solidification of the ink attached near the nozzle outlet.

Next, a printer according to the third embodiment of the present invention will be described with reference to the flowchart of FIG. The printer according to the present embodiment is characterized in that the printing paper in the middle of recording can be discharged when the power supply to the printer is cut off. When it is detected that the main power supply V _m has become Low level (step 100), the voltage V _{SC of the} maintenance signal becomes High level (step 110),
The drive voltage V _CL is supplied by the battery B.

Then, a paper feed mechanism operation command is issued (step 112), and the LF motor 58 is driven to operate the paper feed mechanism 62 via the switching mechanism 61 to eject the print paper in the middle of recording. Then, the PE sensor 64 O
When it is detected by N that the paper feeding is completed (step 114), a drive command for the CR motor 18 is issued (step 120), and the carriage 21 is moved toward the home position. Next, the HP sensor 63 detects that the carriage 21 has reached the capping position (step 130), and the capping mechanism 35.
Is driven (step 140), and the cap member 35a is covered on the nozzle forming surface of each of the heads 22 to 25.
When the end of capping is detected (step 150), the voltage V _{SC of the} maintenance signal changes to the low level (step 160), and the transistor Tr is turned off.
Then, the power supply to the battery B is stopped.

As described above, according to the printer of the third embodiment, even when the power supply to the printer is cut off, in addition to the capping on the nozzle forming surface, the printing paper in the middle of recording is discharged. Can also be done.

[0043]

As described above, according to the first to sixth aspects of the present invention, the nozzle forming surface can be covered with the cap member even when the power supply to the printer is cut off. Therefore, it is possible to prevent the ink ejection performance from deteriorating due to nozzle clogging or ink solidification before the power is restored. That is, even after the power is restored, printing can be performed with the same quality as before the power supply was cut off.

Particularly, in the invention described in claim 2,
In an inkjet printer equipped with an inkjet head that performs recording by ejecting ink droplets while scanning on a recording medium, when the power is cut off, the head is moved to a maintenance mechanism fixed at a predetermined position other than the scanning area. After this, capping processing is performed. Therefore, when the power is turned on again to start printing, the head is always at the fixed position, which is the maintenance position, and therefore, the head can be quickly returned to the end portion of the printing area and printing can be executed.

According to the third aspect of the invention, the nozzle forming surface can be cleaned before the nozzle forming surface is covered with the cap member. Therefore, it is possible to prevent the ink adhering to the vicinity of the outlet of the nozzle from being solidified and the ink ejection performance from being deteriorated before the power is restored.

Further, in the invention described in claim 4, the auxiliary power source means is provided with a charger, and since this charger is normally charged by the power source, a special charging operation is performed. There is no need.

Further, in the invention described in claim 5, the charging body is charged with sufficient electric power for executing the capping process before the ink jet head is driven by turning on the power supply. In other words, since the charging body is sufficiently charged before the inkjet head is removed from the capping position for performing the printing operation, the head can be reliably capped even when the power is cut off immediately after the start of printing. It will be possible.

Further, in the invention described in claim 6, when the detection means detects the disconnection of the power source during the printing operation, the standby power source means ejects the recording medium in the middle of recording to the outside of the apparatus. Since the sheet ejecting unit for performing the processing is provided, it is possible to prevent the recording medium from being unable to be ejected due to the disconnection of the power source.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a main structure of a printer according to first to third embodiments of the present invention.

FIG. 2 is a block diagram showing a control system of the printer shown in FIG.

3 is a circuit diagram of a control circuit 70 shown in FIG.

4 is an explanatory diagram of input / output ports of a CPU 50 shown in FIG.

FIG. 5 is a flowchart showing maintenance control contents executed by the CPU of the printer according to the first embodiment of the present invention.

FIG. 6 is a flowchart showing maintenance control contents executed by a CPU of the printer according to the second embodiment of the present invention.

FIG. 7 is a flowchart showing maintenance control contents executed by a CPU of the printer according to the third embodiment of the present invention.

[Explanation of symbols]

 10 Printer 20 Head 21 Carriage 33 Wiping Mechanism 33a Wiper Member 35 Capping Mechanism 35a Cap Member

Claims (6)

[Claims] 1. A maintenance mechanism having a cap member capable of covering a nozzle forming surface of the inkjet head, in an inkjet printer having an inkjet head for performing recording on a recording medium by ejecting ink droplets from a nozzle. Detecting means for detecting disconnection of power supplied to the device, standby power supply means, and detecting disconnection of power by the detecting means,
An inkjet printer, comprising: a maintenance control unit that drives the maintenance mechanism by the standby power supply unit to perform a capping process of covering at least the nozzle formation surface of the inkjet head with the cap member. 2. The inkjet head is for performing recording by ejecting ink droplets while scanning on a recording medium, and the maintenance mechanism is configured such that the inkjet head is covered by a recording medium in a scanning region of the inkjet head. The maintenance control means is arranged at a position outside the area for recording on the recording medium, and the maintenance control means arranges the inkjet head by the standby power supply means when the maintenance mechanism detects the disconnection of the power supply. 2. The capping process is performed at the position where the capping process is performed while moving to the specified position.
An inkjet printer according to item 1. 3. The maintenance mechanism has a wiper means for cleaning the nozzle forming surface of the inkjet head, and the maintenance control means, before performing the capping process, the nozzle forming surface of the inkjet head by the wiper means. The inkjet printer according to claim 1 or 2, wherein a wiping process for cleaning the above is performed. 4. The standby power source means is provided with a charging body, and the charging body is normally charged by a device power supply, according to any one of claims 1 to 3. Inkjet printer. 5. The charging body is charged with sufficient electric power to execute the capping process after the power is turned on and before the inkjet head is driven. The inkjet printer according to claim 4. 6. The ink jet printer according to any one of claims 1 to 5, wherein when the detection means detects the disconnection of the power supply during the printing operation, the standby power supply means is in the middle of recording. An ink jet printer, comprising: a sheet discharging unit that discharges the recording medium of 1.