Ink-jet recording apparatus

Abstract: An ink-jet recording apparatus is provided with a recording head (10) for discharging ink drops and disposed on a carriage (1) which makes a reciprocating motion in the width direction of a recording medium (P1), a cap (18) for sealing the recording head (10) in a non-printing area and receiving the ink drops discharged for the maintenance of the recording head (10) during a printing operation, an ink receiving member which is capable of moving within a moving locus range of the recording head (10) and disposed in the non-printing area situated opposite to the cap side. As a second ink receiving member (20) is positioned close to the side end of recording paper (P1) in agreement with its width, the distance between the ink receiving member and the side end of the recording paper (P1) is shortened.

Description: The present invention relates to an ink-jet recording apparatus for printing a pattern by ejecting ink drops from nozzle ports onto a recording medium. As a typical ink-jet recording apparatus employs a recording head so constructed as to eject ink drops from nozzle ports by pressurizing ink in a pressure generating chamber by means of a piezo-electric element and a heat generating element, the apparatus needs means for preventing printing-quality deterioration due to the drying of ink near the nozzle ports and the adhesion of dust thereto. One known method that has been adopted to solve the problem above is to move the recording head to a capping unit installed in a standby position each time the printing operation continues for a predetermined length of time, for example, 20 seconds, and a so-called flushing operation is caused to be performed in order to discharge ink drops from the whole nozzle port, so that the nozzle ports are prevented from being clogged with viscous ink sticking thereto. On arrival of the timing of the flushing operation on a side opposite to the side where the capping unit is disposed, however, the flushing operation has to be performed by interrupting the printing operation in order to move the recording head to the capping position. The problem is that the time required for idle traveling is wasteful and this results in lowering the printing speed. In order to solve this problem, an ink-jet recording apparatus has been proposed (Patent Abstracts of Japan Vol. 096, No. 009, 30 September 1996 & JP 08 118674 A, 14 May 1996) such that an ink receptacle is disposed on both sides of recording paper and, on arrival of flushing timing, a recording head is moved to one of the ink receptacles which is situated closer thereto so that the recording head undergoes flushing. With the aforementioned arrangement, it is possible to improve the printing speed because the time required for the idle travel of the recording head is reduced as long as the flushing operation is concerned. When, however, recording paper particularly narrow in width is used for printing, there develops a problem in that the printing speed is rather low for its size as the idle travel distance is extended since the ink receptacles are positioned in synchronization with the maximum recordable width of recording paper. An object of the present invention made in view of the foregoing problems is to provide an ink-jet recording apparatus designed to improve printing throughput by adjusting an ink discharging position in proportion to the width of recording paper so as to shorten the idle travel distance of a recording head when a flushing operation is performed. To solve this object the present invention provides an ink-jet recording apparatus as specified in claim 1 or 6. Preferred embodiments of the invention are described in the subclaims. An ink-jet recording apparatus according to the present invention comprises a recording head for discharging ink drops and disposed on a carriage which makes a reciprocating motion in the width direction of a recording medium, and a cap for sealing the recording head in a non-printing area and receiving the ink drops discharged for the maintenance of the recording head during a printing operation, wherein an ink receiving member capable of moving within a moving locus range of the recording head is provided in the non-printing area situated opposite to the cap side. As the ink receiving member is positioned close to the side end of recording paper in agreement with its width, the distance between the ink receiving member and the side end of the recording paper is shortened with the effect of reducing the idle travel time of the ink-jet recording head. The claims are understood as a first non-limiting approach for defining the invention in general terms. In the accompanying drawings: Fig. 1 is a plan view of an ink-jet recording apparatus embodying the present invention; Figs. 2(a) and 2(b) are sectional views taken along lines A - A and B - B showing the construction of Fig. 1, respectively; Fig. 3 is a block diagram of a flushing control unit embodying the present invention; Figs. 4(a) and 4(b) show the operations of the apparatus above, respectively; Fig. 5 is a plan view of another ink-jet recording apparatus embodying the present invention; Fig. 6 is a block diagram of a flushing control unit fit for use in the above recording apparatus according to the present invention; Fig. 7 is a plan view of still another ink-jet recording apparatus embodying the present invention; and Fig. 8 is a block diagram of a flushing control unit fit for use in the above recording apparatus according to the present invention. Referring the accompanying drawings, there is given a detailed description of embodiments of the present invention. Fig. 1 is a plan view of an ink-jet recording apparatus embodying the present invention, Fig. 2(a) is a sectional view taken along line A - A of Fig. 1, and Fig. 2(b) is a sectional view taken along line B - B of Fig. 1, wherein reference numeral 1 denotes a carriage whose one side is coupled via a coupler 2 to a timing belt 4 which is driven by a motor 3 and the other side is supported by the guide member 7 of a casing 6 via a slider 5 in such a way that it is capable of a reciprocating motion in the width direction of a paper holder 8. An ink-jet recording head 10 for discharging ink drops in response to a printing signal is secured to the underside of the carriage 1, and an ink cartridge 11 is mounted on the surface of the ink-jet recording head 10. One side (the right-end side in Fig. 1) of the paper holder 8 is defined as a reference position, whereas the other end thereof (the left-end side therein) is provided with a paper width adjusting lever 13 for precisely setting sheets of paper different in size such as postcards, those of B5, A4 and the like in such a way that the paper width adjusting lever 13 is movable with respect to a paper supporting plate 14. At the lower end of the paper supporting plate 14, paper feeding rollers 15, 15 for conveying recording paper to a printing area are installed, whereby sheets of recording paper P1, P2 are fed via a platen 16 to paper discharging rollers 17. A capping unit 19 having a cap member 18 for sealing the ink-jet recording head 10 is provided in the home position outside the printing area. Further, reference numeral 20 denotes an ink receiving member 20 featuring the present invention, which ink receiving member 20 accommodates an ink absorbing member 28 and is connected to an arm 21 extending from the paper width adjusting lever 13 whereby to move in opposition to the moving locus of the ink-jet recording head 10 by following the movement of the paper width adjusting lever 13. On the other hand, the platen 16 is provided with windows 22, 23 capable of exposing the surface of the ink receiving member 20 in a position opposite to which the ink receiving member 20 looks when the paper width adjusting lever 13 is moved in synchronization with the paper width. Incidentally, either window 22 or 23 corresponding to the width of recording paper other than the maximum width of what is to be printed, that is, the window 23 according to this embodiment of the present invention, is formed with a surface 23a which is tilted toward the inflowing side. Further, a base 25 is provided with detectors 26, 27 for detecting the position of the ink receiving member in order to output signals, depending on the condition in which the ink receiving member 20 is brought into contact with or situated opposite to one of the windows 22, 23. Reference numeral 29 denotes a roller to guide the arm 21 along the surface of the base 25. Fig. 3 shows an example of a flushing control unit comprising a detection means 31 for detecting printing quantity by computing printing time on receiving a signal from a printing control means (not shown) or computing the number of printing lines; a discharge decision means 32 for deciding flushing timing on the basis of the printing quantity; and a discharge-position decision means 33 for selecting the cap member 18 or the ink receiving member 20 on the basis of the position of the carriage 1 at the flushing timing in order to decide the position of the ink receiving member 20 according to the signals received from the detectors 26, 27 for detecting the position of the ink receiving member 20 when the ink receiving member 20 is selected. The flushing control unit also operates to send signals to a head driving means 34 for causing ink to be discharged from the ink-jet recording head 10 according to the printing signal and to a carriage control means 35 for controlling the movement of the carriage 1, whereby the ink is discharged into the cap member 18 or the ink receiving member 20 positioned close to and outside the recording paper. When recording paper P1 of, for example, B5 is set to the reference position of the paper holder 8 and when the recording paper P1 is brought into contact with the paper width adjusting lever 13 as shown in Fig. 4(a), the ink receiving member 20 is set outside the recording paper P1 of B5 as close as possible thereto and exposed to the window 22 because the movement of the ink receiving member 20 is interlocked with that of the paper width adjusting lever 13. When the printing operation is started in this state, a signal is output from the discharge decision means 32 whenever printing time exceeds the length of time T predetermined by the detection means 31 for detecting printing quantity, for example, 20 seconds or at a point of time the printed lines exceeds 10. The discharge-position decision means 33 selects what is positioned closer to the ink-jet recording head 10 out of the capping unit 19 or the ink receiving member 20, for example, the ink receiving member 20 facing the window 22 according to the present position of the ink-jet recording head 10, and makes the ink-jet recording head 10 move to the ink receiving member 20, thus causing the ink-jet recording head 10 to perform the flushing operation, whereby viscous ink in the proximity of nozzle ports is discharged into the ink receiving member 20. When the flushing operation is finished, the printing operation is restarted and the ink receiving means positioned closer to the ink-jet recording head 10, for example, capping unit 19 is selected as in the aforementioned case at the stage where the printing quantity has reached the predetermined one, and the ink-jet recording head 10 is moved up to a position where it faces the capping unit 19 so as to discharge ink toward the cap member 18. Then the capping unit 19 or the ink receiving member 20 as the ink receiving means, namely, what is positioned closer to the ink-jet recording head 10 is moved to the ink-jet recording head 10 each time the printing quantity reached the predetermined one, so that the flushing operation is performed. Since the ink receiving member 20 is positioned close to recording paper P1 even in the case of narrow recording paper P1, the travel distance of the ink-jet recording head 10 is shortened as much as possible in order to improve the printing throughput when the flushing operation is performed on the non-capping area side. Subsequently, recording paper P1 of B5 that has been loaded is taken out and recording paper P2 of A4 is loaded in order to change the recording paper. When the paper width adjusting lever 13 is then adjusted to the width of the paper P2, the ink receiving member 20 is moved to the window 23 and exposed as shown in Fig. 4(b). When the paper quantity reaches the predetermined one, the discharge-position decision means 33 makes the ink-jet recording head 10 move to what is positioned closer to the ink-jet recording head 10 out of the capping unit 19 or the ink receiving member 20, for example, the ink receiving member 20 facing the window 23 according to the present position of the ink-jet recording head 10, thus causing the ink-jet recording head 10 to perform the flushing operation. When the flushing operation is finished, the printing operation is restarted and as the printing operation proceeds, the recording paper P2 is fed. However, the paper jamming is never occurred because the recording paper P2 slides along a surface 22a which is tilted toward the inflowing side of the recording paper P2 and moves onto the downstream side. Further, since the ink receiving member 20 is situated outside the printing area of the recording paper P2 subjected to the printing operation and also separated by the platen 16 from the recording paper P2, the back of the recording paper P2 is never stained by the ink receiving member 20. Thereafter, the ink-jet recording head 10 is moved to what is positioned closer to the ink-jet recording head 10 out of the capping unit 19 or the ink receiving member 20 facing the window 23, as the ink receiving means each time the printing operation is performed by the predetermined quantity. When characters are printed on a recording medium whose recording width is extremely small such as a postcard, on the other hand, because the ink receiving member 20 is not allowed to face any one of the detectors 26, 27, the discharge-position decision means 33 subjects the capping unit 19 or otherwise ink receiving member 20 to the flushing operation, irrespective of the position of the ink-jet recording head 10, on detecting a state in which no signal is output from any one of the detectors 26, 27, whereby the printing throughput is made improvable by simplifying the control of movement of the carriage. It has been arranged that the flushing position on the non-capping side is determined by making the detectors 26, 27 detect the position of the ink receiving member 20 whose movement is interlocked with that of the paper width adjusting lever 13 of the paper holder 8 according to above-described embodiment of the present invention. However, the ink-jet recording apparatus may be provided with, as shown in Fig. 5, a lever position detector 40 for detecting the position of the paper width adjusting lever 13 of the paper holder 8, and an ink receiving member 41 capable of covering the moving range of the ink-jet recording head 10 in the non-capping area so as to decide an ink discharging position in the non-capping area by deciding the width of recording paper according to a signal from the lever position detector 40 or recording paper size data from a printing-paper selecting switch 42 installed on the panel surface of a host computer or a recording apparatus body (not shown). More specifically, as shown in Fig. 6, the flushing operation is made performable in a position closer to recording paper on the non-capping area side by providing a paper-width detecting means 43 for detecting the width of the recording paper and making the paper-width detecting means 43 input a signal to the discharge-position decision means 33 according to the signal from the lever position detector 40, data on a printing format from the host computer or the signal from the printing-paper selecting switch 42 of the recording apparatus body. Fig. 7 shows another embodiment of the present invention, wherein the carriage 1 is provided with a paper-end detector 44 for detecting the end portion on the non-capping side of recording paper on one hand, and a flushing control unit 30 is provided with a paper-width detecting means 45 for detecting paper width according to the moving distance of the carriage 1 from the reference position at a point of time a signal is output from the paper-end detector 44 on the other as shown in Fig. 8, whereby a signal from the paper-width detecting means 45 is input to the discharge-position decision means 33. According to this embodiment of the present invention, the position adjustment of the ink receiving member can be dispensed with, so that printing preparation work is simplified. In the case of a recording apparatus so arranged that recording paper of predetermined size is accommodated in a cassette in order to change the paper size by replacing the cassette, the determination of the flushing, position on the non-capping area side can be based on the decision of paper width made by detecting the kind of such a cassette. As set forth above, the ink-jet recording apparatus according to the present invention comprises the recording head for sending jets of ink drops to the carriage which makes a reciprocating motion in the width direction of the recording medium, and the cap for sealing the recording head in a non-printing area and receiving the ink drops discharged for the maintenance of the recording head during the printing operation, wherein the ink receiving member capable of moving within the moving locus range of the recording head is provided in the non-printing area situated opposite to the cap side. Therefore, the distance between the ink receiving member and the side end of recording paper can be set to a minimum value, irrespective of the size of the recording paper, and besides the throughput can also be improved by shortening the idle travel distance of the ink-jet recording head during the operation of recovering ink discharge capability.

Claims: An ink-jet recording apparatus comprising: a recording head (10) for ejecting ink drops, and disposed on a carriage (1) reciprocating in a width direction of a recording medium (P1); a cap (18) for sealing the recording head (10) in a first non-printing area and receiving the ink drops discharged for maintenance of the recording head (10) during a printing operation; and an ink receiving member (20) disposed in a second non-printing area situated opposite to the first non-printing area in which the cap (18) is located, characterised in that said ink receiving member (20) is capable of moving within a moving locus range of the recording head (10). The ink-jet recording apparatus according to claim 1, further comprising control means (30, 35) for moving the recording head (10) to the cap (18) or the ink receiving member (20) whose distance from the recording head (10) is shorter so as to effect a flushing operation. The ink-jet recording apparatus according to claim 2, wherein, when a width of the recording medium (P1) has a value not greater than a predetermined one, the control means (30, 35) moves the recording head (10) to one of the cap (18) and the ink receiving member (20) so as to effect a flushing operation at flushing timing. The ink-jet recording apparatus according to any one of claims 1 to 3, further comprising a paper width adjusting lever (13) for moving the ink receiving member (20). The ink-jet recording apparatus according to any one of claims 1 to 4, wherein a plurality of windows (22, 23) for exposing the ink receiving member (20) in agreement with a width of a recording paper (P1) as the recording member are formed in a platen (16) for supporting the recording paper (P1) in a printing area discretely. An ink-jet recording apparatus comprising: a recording head (10) for ejecting ink drops, and disposed on a carriage (1) reciprocating in a width direction of a recording medium (P1); a cap (18) for sealing the recording head (10) in a first non-printing area and receiving the ink drops discharged for maintenance of the recording head (10) during a printing operation; an ink receiving member (20) being disposed in a second non-printing area situated opposite to the first non-printing area; and control means (30, 35) for causing ink to be discharged into the ink receiving member (20) at a discharge position; characterized by : recording-medium-width decision means (43;45) for detecting a width of the recording medium (P1); and discharge position decision means (33) responsive to said recording-medium-width decision means (43;45) to determine said discharge position in dependence of the recording medium width; said control means (30, 35) causing ink to be discharged into the ink receiving member (20) at the discharge position, said discharge position being close to the recording medium (P1). The ink-jet recording apparatus according to claim 6, wherein the ink receiving member (20) is capable of moving within a moving locus range of the recording head (10). The ink-jet recording apparatus according to claim 6 or 7, wherein the recording-medium-width decision means (13, 40; 42) decides the width of the recording medium (P1) according to data or a signal from a host computer or a paper-size selecting switch (42) provided in a recording apparatus. The ink-jet recording apparatus according to anyone of claims 6 to 8, wherein the recording-medium-width decision means (13, 40; 42) is means (40) for detecting a position of a lever (13) of a recording medium loading mechanism. The ink-jet recording apparatus according to claim 6 or 7 wherein the control means (30, 35) subjects the cap (18) or the ink receiving member (20) to flushing operation, irrespective of a position of the ink-jet recording head (10) when the width of the recording medium (P1) for printing has a value not greater than a predetermined one.

Inventors: YAMAGUCHI SHUICHI, YAMAGUCHI, SHUICHI
Applicants: SEIKO EPSON CORP, SEIKO EPSON CORPORATION
Application year: 1997
Main classification: B41J2
IPC codes: B41J2