JPH1029320A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the residual amt. of ink corresponding to the individual difference of a printer by measuring the running distance of a carriage or the running time thereof from a cut-off time to the stop of a carriage and calculating the carriage total mass on the basis of the measured result and storing the calculated result in a memory apparatus. SOLUTION: A rotary encoder 1 is utilized as a position detector for controlling the position of a carriage 9 and, after the drive current of the carriage 9 running at a certain speed is cut off, the distance or time up to the stop of the carriage is measured. By calculating carriage total mass from this result and the braking force acting on the carriage 9, the residual amt. of ink is detected. When an ink cartridge 6 is replaced or delivered, the braking force acting on the carriage 9 is calculated from a known carriage total wt. to be renewed. By this constitution, even if braking force is changed by the individual difference or secular change of the printer, the residual amt. of ink can be accurately detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to detection of the remaining amount of ink in a printer using an ink jet system.

[0002]

2. Description of the Related Art Printers are widely used as devices for recording information output from OA equipment, and one of such systems is an ink jet system. In an ink-jet printer, ink is consumed according to printing, and therefore it is necessary to always supply ink to an ink chamber inside a print head. As a supply source, there is an ink tank which is an ink storage unit. The ink supply system has an ink tank in a location different from the print head and supplies ink by a tube, etc., and an ink cartridge in which the ink tank is mounted on the carriage by itself or integrally with the print head There is a method. In the latter method,
The method of detecting the remaining amount of ink contained in the ink cartridge can be calculated from the data obtained by counting the total number of ejected dots after replacing the ink cartridge, or can be changed according to the amount of ink by using There is a method using a resistance value, a method using a change in capacitance, and a method using a photo sensor.

[0003]

However, in the above-mentioned conventional method, a special device such as an electric circuit or a sensor must be added to detect the remaining amount of ink, and a space for the device is required. And costs may increase. Also, if the drive output torque of the carriage motor is changed for stable running of the carriage by referring only to the change in the remaining amount of ink,
If the frictional force between the carriage and the carriage rail is different due to individual differences of printers or aging, there is a drawback that correct operation cannot be performed.

[0004] In order to solve the above problems, an object of the present invention is to provide a means for detecting the remaining amount of ink in accordance with individual differences and aging of printers without providing an ink remaining amount sensor. It is in.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a position detecting device provided for controlling the position of a carriage, a means for interrupting the driving of the running carriage, and a method for reducing the time. It comprises: means for measuring, means for calculating the total carriage mass or braking force from the measurement information, means for storing the calculation result, and means for comparing the previous total weight of the carriage.

[0006] From the distance or time until the carriage stops after the drive of the carriage is stopped during running, and the braking force of the carriage, the total amount of the carriage is calculated by the general law of dynamics to determine the remaining amount of the ink. Detect and store. The braking force of the carriage can be determined from the stop distance or time of the carriage and the known total mass of the carriage when the ink cartridge is full of ink. This braking force is obtained when the calculated total mass of the carriage becomes larger than the previous value.

[0007]

FIG. 1 is a perspective view showing an ink jet printer to which the present invention is applied. An ink cartridge 6 for supplying ink and a print head 10 are mounted on a carriage 9 attached to the carriage guide rails 4 and 11, and are connected to the pulley 2 by a belt 3. The carriage 9 scans over the recording sheet 8 via the belt 3 when the carriage motor 5 rotates the pulley 2. In synchronization with this, printing is performed by discharging ink corresponding to the print data from the print head 10. The rotary encoder 1 as a position detecting device is attached to the shaft of the carriage motor 5. The encoder 1 rotates the slit plate 22 as shown in FIG. 3 with the movement of the carriage, and the photo sensor 20a detects this as shown in FIG. 2 to generate a two-phase pulse signal, and counts this signal. Thus, the accurate position of the carriage can be input as an encoder value. This position detecting device includes, in addition to a rotary encoder, a belt-shaped transparent film 24 provided in parallel with a carriage rail and provided with a pattern 23, as shown in FIG.
May be a belt-type encoder that detects. The belt is not limited to the film 24, but may be made of a material that does not transmit light, such as metal, provided with slits like the pattern 23. In the printer of the present invention, a timer as a means for measuring time is provided with a control CPU.
One or more channels are provided inside or outside. In the present invention, one or a plurality of general-purpose ones are used.

FIG. 5 is a diagram showing the relationship between the speed and the position of the carriage in the embodiment of the present invention, and FIG. 6 is a diagram showing the relationship between the speed and the time. When the drive of the running carriage is interrupted at the time t1 at the position C1, the carriage travels to the position C2 and stops by the braking force of the carriage. The time at this time is t2.

FIG. 9 is a simple flowchart of the operation of detecting the remaining amount of ink provided by the present invention. When a request for the remaining ink amount detection work is generated, the printer first moves the carriage at an arbitrary constant speed, and then cuts off the current supplied to the carriage motor at an arbitrary timing. Immediately before the interruption, the speed of the carriage is measured. To measure the speed, as shown in FIG. 7, the first encoder value after the start of the measurement is stored as C1, the timer initial count is set to T, the timer is started, and the encoder value is increased by the pulse number n specified by the CPU. There is a method of measuring the count t of the timer after the input, and obtaining it from the difference between T and t and the distance of n encoders from which the carriage has advanced during this time. V = pn / {b (T−t)} Equation 1-1 where V: carriage speed b: time per count of timer p: distance per count of encoder

When the timer is used for up-counting, the operation starts from count zero. In this case, Equation 1-1 is as follows. V = pn / (bt) Expression 1-2 Also, as shown in FIG. 8, the first encoder value after the start of the measurement is stored as C1, and only the time that the encoder value advances several times elapses. Is set to the timer and started, and after the time is up, the encoder value is input again as C2, and the difference from the initial value n = | C2-C
There is a method of obtaining from 1 | and the time corresponding to the timer count T. In this case, the speed V of the carriage is obtained by the following equation. V = pn / (bT) Expression 1-3

Next, the value C1 of the encoder is stored when the supply current to the carriage motor is cut off. At the same time, the timer is set with an initial count ts sufficient for a sufficient time to stop the carriage and then started. In the carriage, the sum of the frictional force between the carriage and the carriage rail and the resistance of the carriage motor transmitted from the belt acts as a braking force f, and the braking force causes the carriage to decelerate and stop. After the time-up, the encoder value C2 is stored. Since the kinetic energy of the carriage immediately before the interruption of the current to the carriage motor is consumed by the above-described braking force, the following equation holds. 1/2 mV ² = fdx (2) where m: total carriage mass V: speed of the carriage immediately before current interruption f: sum of the resistance of the carriage motor and the frictional force of the carriage rail dx: the braking distance of the carriage = p | C2−C1 | p: distance per encoder count C2: encoder value after carriage stop C1: encoder value when current is cut off Further, the total mass m of the carriage is obtained from Equation 2 as follows. m = 2fdx / V ² Equation 3

When the printer is first turned on at the time of shipment, it is considered that an unused ink cartridge filled with ink is mounted, and the braking force f is obtained from the known total mass M of the carriage by the above operation. That is, from Equation 3, f = MV ² / (2dx) Equation 4 The braking force f and the carriage total mass M are written in an EEPROM so that they can be rewritten. The total carriage mass written in the EEPROM is mE. After that, EEPROM
From the value of f read from
Can be sought. The difference between m and the total mass M of the carriage when the ink is full is the amount of used ink. If the amount of used ink is subtracted from the initial amount of ink, that is, the remaining amount of ink at that time is used. The quantity has been determined. This operation is performed as necessary after turning on the power, after a certain period of time, after printing a certain number of lines, printing a certain number of pages, or printing a certain number of dots.
ME in the EPROM is rewritten each time as mE = m.

When the ink cartridge is replaced, the total mass m of the carriage becomes equal to M due to the ink fullness, becomes larger than mE stored at the time of the previous measurement, and m> mE
Is satisfied, the braking force f is obtained again with m = M. As a result, it is possible to cope with a change in the braking force due to the use environment of the printer or aging. Even when the braking force f is measured without mounting the ink cartridge when the printer is shipped, m> mE is always satisfied when the ink cartridge is first mounted next, and the normal measurement of the braking force f is performed. Then, the initial braking force f and mE (= M) are stored. FIG. 11 shows a simple flowchart of these operations. By reading the values of mE and f, the printer performs necessary controls such as an out-of-ink alarm, interruption of printing, and a change in the torque of the carriage motor.

Next, a second embodiment of the present invention will be described. This flowchart is shown in FIG. This is a method for measuring the time until the carriage stops after the drive current of the carriage motor is cut off. At the time of current interruption, the timer is set to the initial count number ts that is sufficient for the carriage to stop for a sufficient time to start and then started. The timer continues counting until the set count number ts ends, during which the carriage stops. A latch circuit that latches the count value of the timer in synchronization with the encoder pulse latches the count value of the timer at that time every time an encoder pulse is input. After the time-up, the latched count value is the count value of the timer when the last encoder pulse is generated, that is, when the carriage stops, so that the count value between the initial count value of the timer and the count value latched last is used. The difference multiplied by the time per count of the timer is the time t from the interruption of the current to the stop of the carriage. t = | ts−te | × b Expression 5 ts: Timer initial count te: Timer final latch count b: Time per timer count

Since the speed V at the time of current interruption becomes zero due to the braking force f during the braking time t during the time determined here, the following equation is established from the law of conservation of momentum. mV = ft Equation 6 By deformation, m = ft / V Equation 7 The total carriage mass m is obtained by Equation 7. Further, the equation for calculating the braking force at the time of ink cartridge replacement is as follows from equation 7, f = MV / t...

[0016]

According to the present invention, the distance from when the drive current of the carriage running at a certain speed is cut off to when the carriage stops using the position detecting device provided for controlling the position of the carriage. Alternatively, the remaining amount of ink is detected by measuring time and calculating the total mass of the carriage from the result and the braking force acting on the carriage. When the ink cartridge is replaced or shipped, the braking force acting on the carriage is obtained from the known total mass of the carriage and updated. Therefore, it is possible to detect the remaining amount of ink without using a special device for that purpose, and it is possible to save space for the device,
The cost is low. Further, since it is possible to know both the change in the remaining amount of ink and the braking force acting on the carriage, there is an advantage that the remaining amount of ink can be correctly detected even when the braking force changes due to individual differences of printers or aging. is there.

[Brief description of the drawings]

FIG. 1 is an explanatory perspective view of a recording apparatus to which the present invention can be applied.

FIG. 2 is an explanatory diagram of a sensor unit of an encoder for detecting a carriage position.

FIG. 3 is an explanatory diagram of a rotary encoder attached to a carriage motor.

FIG. 4 is an explanatory view of a slit of a belt type linear encoder.

FIG. 5 is a graph showing a relationship between a carriage speed and a carriage position from a current interruption to a carriage motor to a carriage stop.

FIG. 6 is a graph showing a relationship between a carriage speed and a time from a current interruption to a carriage motor to a carriage stop.

FIG. 7 is a flowchart illustrating a method of measuring a carriage speed by time measurement.

FIG. 8 is a flowchart illustrating a method of measuring a carriage speed by distance measurement.

FIG. 9 is a flowchart illustrating a carriage mass detection method according to the first embodiment of the present invention.

FIG. 10 is a flowchart illustrating a carriage mass detection method according to a second embodiment of the present invention.

FIG. 11 is a flowchart illustrating the entire system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotary encoder 2 Pulley 3 Belt 4 Guide shaft 5 Carriage motor 6 Ink cartridge 7 Pulley 8 Recording sheet 9 Carriage 10 Recording head 11 Guide shaft 20 Photosensor 21 Encoder slit plate 22 Rotary encoder 23 Pattern 24 Belt transparent film

Claims (2)

[Claims] A carriage for mounting an ink cartridge for containing ink, a print head for discharging ink supplied from the ink cartridge, and a position detecting device provided for controlling the position of the carriage. An ink jet printer comprising: means for interrupting driving of a carriage motor during carriage travel; means for measuring a travel distance or a travel time of the carriage from the time of interruption to carriage stop; and a carriage based on the measurement result. An ink jet printer comprising: means for calculating a total mass; means for storing the calculation result in a storage device; and determining the remaining amount of ink from the total mass of the carriage. 2. The ink jet printer according to claim 1, wherein before storing the calculated total weight of the carriage, means for comparing the total weight of the carriage with the previously stored total weight of the carriage, and the result of the comparison, the latest total weight of the carriage is better. Means for calculating the frictional force of the carriage when it is smaller and storing the calculation result in a storage device.