JP2005238608A - Ink jet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high definition ink jet recorder in which unevenness of an image is eliminated by preventing sheet discharge smear through a simple arrangement. <P>SOLUTION: Position of a part on a recording medium printed with high print ratio is stored and the fixing completion seconds determined by such parameters as the print ratio, the type of recording medium, and environmental conditions is set at that part. If fixing has not yet completed at such a part as set to cause smear of a previous page during print of next page, print is waited after feeding a sheet and an image is completed without interrupting print. The sheet is discharged upon elapsing several seconds after completing fixing of the remaining part on the previous page. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ink jet recording apparatus that records using a recording liquid (ink), and more particularly to an ink jet recording apparatus that prevents smear due to rubbing during paper discharge by minimizing a decrease in printing throughput.

  A recording apparatus such as a printer, a copying machine, or a facsimile is configured to record an image having a dot pattern on a recording material such as paper or a plastic thin plate based on image information.

  The recording apparatus can be classified into an ink jet type, a wire dot type, a thermal type, a laser beam type, and the like according to a recording method. Among them, an ink jet type (ink jet recording apparatus) is configured to discharge ink (recording liquid) droplets from the discharge port of a recording head and attach the ink droplets to a recording material for recording.

  In recent years, many recording apparatuses have been used, and these recording apparatuses are required to have high-speed recording, high resolution, high image quality, low noise, and the like. The ink jet recording apparatus can be cited as a recording apparatus that meets such requirements.

  However, in an ink jet recording apparatus, in order to perform recording using an aqueous liquid ink in many cases, it is necessary to have a fixing time for drying the ink.

  In an apparatus with a low recording speed, since there was a time until the next page was printed, ink fixing was not regarded as a problem. However, in a recording apparatus capable of outputting 4 to 5 or more sheets per minute with the recent A4 size, particularly in a recording apparatus capable of outputting 10 or more sheets per minute, there is a problem that smearing occurs. Has become prominent. That is, if there is a portion with a slightly high printing ratio, the next printed matter comes before the ink is completely dried, and the portion is rubbed.

  Conventional solutions for paper smears include the provision of a fixing mechanism using a thermal heater, or a mechanical structure to prevent rubbing against the previous paper ejected on the paper ejection mechanism. At the point of time, the mainstream is to drive the paper discharge mechanism to stack the paper. In addition, when the mechanical mechanism is insufficient, there is a combination with a delay control of the operation of the mechanical mechanism for stacking after discharging.

  However, in any method, the specific mechanism becomes large, and it is difficult to adopt it because it causes an increase in size and cost.

Therefore, conventionally, a method has been employed in which a portion where the printing ratio of the previous paper is high is detected and the recording speed of the next paper is delayed to prevent paper discharge smear (for example, patents). Reference 1).
JP 7-205416 A

  However, when the method of delaying the recording speed of the next sheet is used, there is no problem with monochrome images such as text, but during color recording, a time difference occurs in the recording time for each recording area, and There is a problem in that color unevenness occurs in each recording region due to factors such as ink penetration speed.

  SUMMARY An advantage of some aspects of the invention is that it provides a high-quality inkjet recording apparatus that prevents paper discharge smear with a simple configuration and does not cause unevenness in an image.

In order to achieve the above object, the present invention provides an ink jet recording apparatus characterized by the following (1) to (8).
(1) In an ink jet recording apparatus that records on a print medium using ink,
A discharge means for discharging the recorded print medium;
Detecting means for detecting an area where an ink amount per unit area is applied exceeding a predetermined amount on the preceding print medium;
Of the detected areas, the amount of ink applied to the first area where the leading edge of the subsequent print medium discharged from the discharge means comes into contact with the preceding print medium before being discharged from the discharge means. A first period of time until contact is allowed according to the criteria based on,
A second period until the succeeding print medium is allowed to contact the preceding print medium according to a criterion based on the amount of ink applied to the area after the first area among the detected areas; ,
It has control means for starting recording of the subsequent print medium after the first period has elapsed, and discharging the subsequent print medium after the second period has elapsed after the end of recording.
(2) In an inkjet recording apparatus that records on a print medium using ink,
A discriminating means for discriminating whether color data is included in the recording data to the print medium;
A discharge means for discharging the recorded print medium;
Detecting means for detecting an area where an ink amount per unit area is applied exceeding a predetermined amount on the preceding print medium;
Of the detected areas, the amount of ink applied to the first area where the leading edge of the subsequent print medium discharged from the discharge means comes into contact with the preceding print medium before being discharged from the discharge means. A first period of time until contact is allowed according to the criteria based on,
A second period until the succeeding print medium is allowed to contact the preceding print medium according to a criterion based on the amount of ink applied to the area after the first area among the detected areas; ,
When color data is included in the recording data to the succeeding print medium, recording of the succeeding print medium is started after the first period has elapsed, and after the second period has elapsed after the recording, First control means for discharging
When color data is not included in the recording data to the subsequent print medium, recording is performed up to the position where the subsequent print medium does not contact the first area, and the recording is resumed after the first period has elapsed, A second control unit for discharging the succeeding print medium after the second period has elapsed after the recording is completed.
(3) The first area is changed based on an ink amount per unit area applied to a leading end area on the subsequent print medium.
(4) The amount of ink per unit area is detected by the number of dots recorded per unit time.
(5) The criterion is changed according to the type of the recording medium.
(6) The determination criterion is changed according to at least one of environmental temperature and humidity.
(7) The determination criterion is changed according to at least one combination of a change in ink discharge amount and a change in ink type.
(8) The detection means detects an area for each area obtained by dividing the print medium into areas with a predetermined length in the conveyance direction,
The determination unit is characterized in that a longest period among periods detected in the same area is used as a representative value in the area.

  In addition, the following effect | action is exhibited based on the above-mentioned structure.

  According to the present invention, printing is continued at the maximum speed of the recording device by continuing printing without reducing the recording speed for the portion where the fixing is completed, and the discharge smear is not completed because the fixing is not completed. Since only the portion that is likely to occur is weighted before that, it is possible to minimize a decrease in printing speed while preventing paper discharge smear. Further, since printing is not interrupted in the middle of color printing, an image having no printing unevenness can be recorded.

  As described above, according to the present invention, regarding the portion where the fixing is completed, the printing is continued at the maximum speed of the recording device by continuing the printing without reducing the recording speed, and the fixing is completed. Since only the portion that is likely to cause paper discharge smear is weighted before that, it is possible to prevent paper discharge smear and minimize the decrease in printing speed. Further, since printing is not interrupted in the middle of color printing, an image having no printing unevenness can be recorded. Therefore, an inkjet recording apparatus capable of high-speed recording and high image quality can be provided.

  First, an outline of an ink jet recording apparatus to which the present invention can be applied will be described.

  FIG. 1 is a schematic perspective view of an ink jet recording apparatus of the present invention.

  In FIG. 1, a recording medium P that is a recording medium during normal inkjet recording is sandwiched between a conveyance roller 1 and a pinch roller 2 that is driven by the conveyance roller 1, and is guided onto a platen 3 by the rotation of the conveyance roller 1. It is conveyed in the direction of arrow A in the figure while being supported. At this time, the platen 3 supports the back surface of the recording medium S so that the distance between the ink discharge surface of the inkjet head 4 and the surface of the recording medium P facing the ink discharge surface is maintained at a constant or predetermined distance. Thereafter, the recording medium P conveyed on the platen 3 is sandwiched between the rotating discharge rollers 12 and 15 and the spurs 13 and 16 which are rotating bodies driven by the rollers. After the image recording is performed, the discharge rollers 12 and 15 are rotated and discharged from the platen 3 onto the discharge tray 17.

  Further, a recording medium presser 14 is provided on the platen 3 in order to restrict the end of the recording medium S in the direction intersecting the transport direction A from floating toward the ink jet head 4. The ink jet head 4 is detachably mounted on a carriage 7 that is reciprocated along two guide rails 5 and 6 by a driving means such as a motor (not shown) in a posture for ejecting ink toward the recording medium P. Yes. The carriage movement direction is a direction that intersects the recording medium conveyance direction (arrow A direction), and is called a main scanning direction. On the other hand, the recording medium conveyance direction is called a sub-scanning direction.

  The ink jet head 4 is provided with means (for example, a heating resistor element) that generates thermal energy as energy used for ink ejection, particularly in the ink jet recording system, and changes the state of the ink (film boiling) by the thermal energy. High density and high definition of the recording are achieved by using the method of generating. In addition, you may utilize vibration energy not only in the system by such a heat energy.

  The inkjet head 4 is provided with a plurality of nozzle rows for ejecting different colors of ink. In the case of the present invention, four types of inks of black, cyan, magenta, and yellow are employed, and pigment ink is used for black ink, and dye ink is used for cyan, magenta, and yellow ink. A plurality of independent ink tanks 8 are detachably mounted on the tank mounting unit 9 corresponding to the four types of ink discharged from the inkjet head 4. The tank mounting unit 9 and the inkjet head 4 are connected to each other by a plurality of liquid supply tubes 10 corresponding to the colors of the inks, and each ink tank 8 is mounted on the tank mounting unit 9 so as to be stored in each ink tank 8. It is possible to independently supply the ink of the selected color to each nozzle row of the inkjet head 4 corresponding to each ink color.

  Further, the recovery unit 11 faces the ink ejection surface of the inkjet head 4 in a non-recording area that is within the reciprocating movement range of the inkjet head 4 and outside the passing range when the recording medium P is conveyed. Has been placed. The recovery unit 11 includes a cap portion for capping the ink discharge surface of the ink jet head 4, a suction mechanism for forcibly sucking ink from the ink jet head 4 with the ink discharge port surface being capped, and contamination of the ink discharge surface. And a cleaning blade for wiping off.

  The details of this embodiment will be described with reference to the flowchart of FIG. 2 for such a recording apparatus.

  FIG. 2 is a flowchart of paper discharge smear control in the ink jet recording apparatus of the present invention. FIG. 3 is a diagram in which the recording apparatus of the present invention discharges the recording medium. FIG. 4 is a diagram in which the discharged recording medium P1 is divided into areas for each recording band.

  First, paper feeding is performed in S1. At this time, the recording medium P2 in FIG. 3 is conveyed only to a position slightly beyond the discharge roller 12 even when there is no print data. Of course, if there is print data in the previous area, it stops at the print position. Next, in S2, the remaining smear wait time set in the Xn to X bands in FIG. 4 is calculated. The width of each band in FIG. 4 is set to be the same as the print width of the head in the recording head 4. As shown in FIG. 3, the point where the subsequent recording medium P2 starts to contact the preceding recording medium P1 discharged after recording is set as the landing point x. The position of the landing point x may be variable depending on the type of recording medium and the printing ratio applied on the subsequent recording medium P2. A band including the landing point x is set as X, and bands before and after that are set as X−n and X + n. In this embodiment, first, the dot count value of the black data is acquired for each print band, and the specified number of seconds is stored in the memory as the fixing completion time at which discharge smear does not occur for the portion determined to be equal to or higher than the specified print ratio. set. At the same time, the subtraction timer counter is started. In S3, if there is a fixing completion time in the Xn to X bands at the time when paper feeding is executed, the process proceeds to S4 and waits for the remaining time. Of course, the remaining time of the first sheet is 0 when the power is just turned on or after printing for a while. If there is no remaining time and after the wait is completed, the process proceeds to S5, and printing is performed up to the final band without interrupting printing. In S6, the remaining fixing completion time set in the X + 1 to X + n bands is calculated. In S7, if there is a fixing completion time in the bands X + 1 to X + n when printing is completed, the process proceeds to S8 and waits for the remaining time. If there is no remaining time and after the wait is completed, the process proceeds to S9 to perform a paper discharge operation. When printing a plurality of sheets continuously, the next recording medium is fed, but the control is continued in the same manner. Here, the fixing completion time for each band of the X + 1 to X + n bands can be set slightly shorter than the fixing completion time for each band of the Xn to X bands. This progresses while rubbing the tip of the recording medium P2 on the image printed on the Xn to X bands on the recording medium P1, whereas the recording medium P2 has an image printed on the X + 1 to X + n bands. When the paper is discharged, the contact is made with a slight pressure that is only the weight of the recording medium itself. Further, the fixing completion time for each band in the Xn to X bands may be overwritten on a small one with priority given to the one having a large remaining time. Similarly, the same configuration can be taken in the X + 1 to X + n bands.

  As described above, for the part where fixing has been completed, printing is continued at the maximum speed of the recording device by continuing printing without reducing the recording speed, and fixing is not completed, causing paper smearing. Since only such a portion is weighted in front of it, it is possible to prevent paper discharge smear and minimize a decrease in printing speed. Further, since printing is not interrupted in the middle of color printing, an image having no printing unevenness can be recorded.

  The second embodiment is provided with means for determining whether or not the recording data is color data in comparison with the first embodiment. For example, when the recording medium includes color data at the time of feeding, the smear control described in the first embodiment is performed, and when only monochrome data is used, the conventional smear control as disclosed in JP-A-7-205416 is performed. It is. If it is not color data, even if a delay such as a wait time is entered during printing, printing unevenness does not occur, which is effective.

  In the third embodiment, the value of the fixing completion time is further changed according to the type of the recording medium as compared with the first embodiment. Further, the fixing completion time may be changed depending on the environmental temperature and humidity. Furthermore, when the ejection amount is changed by replacing the recording head, or when the ink type is different and the fixability is significantly different, the control parameters can be changed by automatically reading the ID according to those characteristics, It is also effective to change the control parameters automatically by the driver settings, or by a method such as user input.

(Other)
The present invention brings about an excellent effect in a recording apparatus using an ink jet recording head that performs recording by forming thermal liquid using thermal energy among ink jet recording methods.

  As its typical configuration and principle, for example, those performed using the basic principle disclosed in US Pat. Nos. 4,723,129 and 4,740,796 are preferable. This method can be applied to both the so-called on-demand type and continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or liquid path holding the liquid (ink). By applying at least one drive signal corresponding to the recording information and giving a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, the thermal energy is generated in the electrothermal transducer, and the recording head This is effective because film boiling occurs on the heat acting surface, and as a result, bubbles in the liquid (ink) corresponding to the drive signal can be formed. By the growth and contraction of the bubbles, liquid (ink) is ejected through the ejection opening to form at least one droplet. It is more preferable that the drive signal has a pulse shape, since the bubble growth and contraction is performed immediately and appropriately, and thus it is possible to achieve discharge of a liquid (ink) having particularly excellent responsiveness. As this pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further excellent recording can be performed by employing the conditions described in US Pat. No. 4,313,124 of the invention relating to the temperature rise rate of the heat acting surface.

  As the configuration of the recording head, in addition to the combination configuration (straight liquid channel or right-angle liquid channel) of the discharge port, the liquid channel, and the electrothermal transducer as disclosed in each of the above-mentioned specifications, the thermal action A configuration using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose a configuration in which the portion is arranged in a bent region, is also included in the present invention. In addition, for a plurality of electrothermal transducers, Japanese Patent Application Laid-Open No. Sho 59-123670 that discloses a configuration in which a common slit is used as a discharge portion of the electrothermal transducer or an aperture that absorbs pressure waves of thermal energy is provided. The effect of the present invention is also effective as a configuration based on Japanese Patent Application Laid-Open No. 59-138461 which discloses a configuration corresponding to the discharge unit. That is, whatever the form of the recording head is, according to the present invention, recording can be performed reliably and efficiently.

  Furthermore, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium that can be recorded by the recording apparatus. As such a recording head, either a configuration satisfying the length by a combination of a plurality of recording heads or a configuration as a single recording head formed integrally may be used.

  In addition, even the serial type as shown in the above example can be connected to the main body of the recording head or attached to the main body of the device so that electrical connection with the main body of the device and ink supply from the main body are possible. The present invention is also effective when a replaceable chip type recording head or a cartridge type recording head in which an ink tank is integrally provided in the recording head itself is used.

  In addition, it is preferable to add a recording head ejection recovery means, a preliminary auxiliary means, and the like as the configuration of the recording apparatus of the present invention, since the effects of the present invention can be further stabilized. Specifically, heating is performed using a capping unit, a cleaning unit, a pressurizing or suction unit, an electrothermal transducer, a heating element different from this, or a combination thereof. Examples thereof include a preliminary heating unit for performing the discharge and a preliminary discharge unit for performing discharge different from the recording.

  Also, regarding the type or number of mounted recording heads, two or more recording heads may be provided corresponding to a plurality of inks having different recording colors and densities. That is, for example, as a recording mode of the recording apparatus, not only a recording mode of only a mainstream color such as black, but also a recording head may be configured integrally or by a combination of a plurality of different colors, Alternatively, the present invention is extremely effective for an apparatus having at least one of full-color recording modes by color mixing.

  In addition, the ink jet recording apparatus according to the present invention may be used as an image output terminal of an information processing apparatus such as a computer, a copying apparatus combined with a reader, or a facsimile apparatus having a transmission / reception function. The thing etc. may be sufficient.

  In the present invention, recording means not only attaching ink to a medium such as paper based on data representing characters or images, but also attaching meaningless data such as random data or solid data. Also means.

1 is a schematic perspective view of an ink jet recording apparatus of the present invention. 6 is a flowchart of sheet discharge smear control in the ink jet recording apparatus of the present invention. FIG. 4 is a diagram in which the recording apparatus of the present invention discharges a recording medium. FIG. 4 is a diagram in which the discharged recording medium P1 is divided into areas for each recording band.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conveyance roller 2 Pinch roller 3 Platen 4 Inkjet head 5 Guide rail 6 Guide rail 7 Carriage 8 Ink tank 9 Tank mounting unit 10 Liquid supply tube 11 Recovery unit 12 Discharge roller 13 Spur 14 Recording sheet press 15 Discharge roller 16 Spur 17 Discharge tray P Recording medium x Landing point

Claims (8)

In an inkjet recording apparatus that performs recording on a print medium using ink,
A discharge means for discharging the recorded print medium;
Detecting means for detecting an area where an ink amount per unit area is applied exceeding a predetermined amount on the preceding print medium;
Of the detected areas, the amount of ink applied to the first area where the leading edge of the subsequent print medium discharged from the discharge means comes into contact with the preceding print medium before being discharged from the discharge means. A first period of time until contact is allowed according to the criteria based on,
A second period until the succeeding print medium is allowed to contact the preceding print medium according to a criterion based on the amount of ink applied to the area after the first area among the detected areas; ,
An ink jet recording apparatus comprising: a control unit that starts recording of the subsequent print medium after the first period has elapsed, and discharges the subsequent print medium after the second period has elapsed after the end of recording. In an inkjet recording apparatus that performs recording on a print medium using ink,
A discriminating means for discriminating whether color data is included in the recording data to the print medium;
A discharge means for discharging the recorded print medium;
Detecting means for detecting an area where an ink amount per unit area is applied exceeding a predetermined amount on the preceding print medium;
Of the detected areas, the amount of ink applied to the first area where the leading edge of the subsequent print medium discharged from the discharge means comes into contact with the preceding print medium before being discharged from the discharge means. A first period of time until contact is allowed according to the criteria based on,
A second period until the succeeding print medium is allowed to contact the preceding print medium according to a criterion based on the amount of ink applied to the area after the first area among the detected areas; ,
When color data is included in the recording data to the succeeding print medium, recording of the succeeding print medium is started after the first period has elapsed, and after the second period has elapsed after the recording, First control means for discharging
When color data is not included in the recording data to the subsequent print medium, recording is performed up to the position where the subsequent print medium does not contact the first area, and the recording is resumed after the first period has elapsed, 3. The ink jet recording apparatus according to claim 1, further comprising a second control unit that discharges the subsequent print medium after the second period has elapsed after the recording is finished.   3. The ink jet recording apparatus according to claim 1, wherein the first area is changed based on an ink amount per unit area applied to a leading end area on the subsequent print medium.   4. The ink jet recording apparatus according to claim 1, wherein the ink amount per unit area is detected by the number of dots recorded per unit time.   The inkjet recording apparatus according to claim 1, wherein the determination criterion is changed according to a type of the recording medium.   6. The ink jet recording apparatus according to claim 1, wherein the determination criterion is changed according to at least one of environmental temperature and humidity.   The ink jet recording apparatus according to claim 1, wherein the determination criterion is changed in accordance with at least one combination of a change in ink ejection amount and a change in ink type. The detection means detects a region for each area obtained by dividing the print medium into areas with a predetermined length in the conveyance direction,
The ink jet recording apparatus according to claim 1, wherein the determination unit sets a longest period among periods for the areas detected in the same area as a representative value in the area.

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