JP2011152768A - Image forming device and controlling method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device which can prevent soiling of neighbouring heads even during the execution of nozzle recovering action through blind discharging of ink, while reducing its cost and saving space. <P>SOLUTION: In the image forming device including a plurality of ink discharging means 50a and 50b having a plurality of nozzles 51-58 to discharge ink from the plurality of nozzles to the recording medium 10 to form images onto recording medium by discharging the ink and simultaneously movable independently at least in the carrying direction X of the recording medium and a plurality of capping means 6a and 6b individually capable to block the nozzle of each ink discharging means and executing the blind discharging of ink as the nozzle recovering action of the ink discharging means, during the head recovering action of one ink discharging means, the nozzle of the other ink discharging means is blocked with at least one of the capping means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus of an ink jet recording system having a configuration in which ink that does not contribute to image formation is ejected idly.

  In an inkjet image forming apparatus that performs printing by ejecting a single color or a plurality of colors of ink from a liquid ejection head onto a recording medium, a small ink droplet is ejected from the nozzle of the liquid ejection head onto the recording medium, and characters are printed. And forming images. In such an ink jet image forming apparatus, if ink is left without being ejected, moisture or the like evaporates in the nozzle openings, causing ink thickening, and normal ejection cannot be performed when ink is ejected next time. . For this reason, in this type of image forming apparatus, ink that has not contributed to image formation is ejected at regular intervals so that no thickened ink remains in the nozzle. Ink consumption due to ejection is a problem.

  Thus, a configuration is known in which a head that is not used for printing is capped to prevent ink drying and to suppress ink consumption due to idle ejection. For example, Patent Document 1 discloses a configuration including a black head portion that discharges black ink and color ink and a cap member that individually closes the color head portion for the purpose of making maintenance of black ink and color ink independent. Has been.

  Patent Document 2 discloses a configuration in which two ink receiving portions that receive preliminary ejection ink are provided and preliminary ejection is performed by selecting one of them for the purpose of preventing contamination in the recording apparatus due to preliminary ejection.

  Patent Document 3 discloses that a partition member is provided to prevent contamination around the head due to the generated mist for the purpose of preventing contamination around the ink mist during idle ejection.

  Patent Document 4 discloses a configuration in which a suction recovery process is partially performed only on a recording head in which an ink ejection failure has occurred, and a cap member that performs the recovery process is separated.

  Patent Document 5 discloses a configuration of a positioning mechanism when the maintenance unit is moved.

  Patent Document 6 discloses a configuration in which all caps are divided into two or more cap groups, the nozzles can be closed simultaneously with all caps, and the nozzles can be closed independently with any cap group.

  Patent Document 7 discloses a configuration in which a cap member that is movable with respect to a head located in a portion exceeding the paper size is disposed at an opposing position to perform idle ejection and perform a recovery process.

  Patent Document 8 discloses a configuration in which maintenance is performed on a head having a large number of nozzles, and ink is uniformly sucked from each ejection port.

  In the above conventional configuration, it is possible to perform pressure discharge, suction recovery, and idle discharge independently, but the head is made of mist-like ink that is generated when idle discharge is performed with the nozzle closed with a cap member. There is a problem that will be soiled.

  That is, in Patent Document 1, a cap member for a black head provided with a maintenance mechanism is moved to a position facing the color head unit, and the color head unit is closed with the cap member to perform idle discharge. When empty ejection is performed, the closed space is filled with mist-like ink. In order to prevent or suppress such fouling, it is necessary to open the cap from the closed state, but mist-like ink at the time of opening will leak.

  Also in Patent Document 2, since the preliminary ejection is performed in the closed state of the head by the cap member, there is a problem that the head is soiled with mist ink filled in the closed space, as in the case of performing the idle ejection in the closed state. .

  In patent document 3, since it is necessary to add a partition member as a new component as a countermeasure against dirt caused by mist, there are problems such as securing space for the member and increasing costs.

  In Patent Document 4, the cap member that performs the recovery process is separated, but the configuration for the control of performing the idle discharge on the cap member is not disclosed, and it is caused by the occurrence of mist that occurs when performing the idle discharge on the cap member. It also does not describe the problem and how to solve it.

  In Patent Document 5, the maintenance unit can be moved, but the configuration for the control for performing the idle discharge to the maintenance unit is not disclosed, and there are other problems due to the occurrence of mist generated when performing the idle discharge to the maintenance unit. There is no description about control related to the elimination of problems caused by temporary diversion of cap members for colors.

  In Patent Document 6, the cap member can be completely closed and individually closed, but the configuration for the control of performing the idle discharge to the cap member is not disclosed, and the generation of mist generated when the cap member is idlely discharged is not disclosed. There is no mention of the problem and the control related to the solution. Further, in order to perform the head recovery process, it is necessary to provide a maintenance mechanism for all cap units, resulting in a complicated configuration and an increase in cost. Furthermore, in order to realize individual cap operations for each head unit, it is necessary to dispose a drive unit such as a stepping motor for each head line, resulting in an increase in size and cost of the apparatus.

  In Patent Document 7, idle discharge is performed on a movable cap member, but there is no description of a problem caused by the occurrence of mist that occurs when idle discharge is performed on the cap member, and control related to elimination of the defect.

  In Patent Document 8, maintenance is performed for a head having a large number of nozzles, but this maintenance is described only for suction maintenance, not for idle ejection, and other maintenance methods and problems and methods for solving the problems are described. It has not been.

  An object of the present invention is to propose an image forming apparatus capable of preventing contamination of surrounding heads at a low cost and in a small space even when a nozzle recovery operation is performed by empty ink ejection.

  The present invention has a plurality of nozzles for ejecting ink, ejects ink from the plurality of nozzles toward the recording medium to form an image on the recording medium, and independently at least in the recording medium conveyance direction. In an image forming apparatus comprising a plurality of movable ink discharge means and a plurality of cap means capable of individually closing the nozzles of each ink discharge means, and performing idle ink discharge as a nozzle recovery operation of the ink discharge means, During the nozzle recovery operation for one ink discharge means, the nozzles of another ink discharge means are closed using at least one of the cap means.

  In the image forming apparatus according to the present invention, a cap moving unit that moves each cap unit to a facing position facing the nozzle and a retracted position not facing the nozzle, and each cap member abuts against the nozzle at the facing position and closes. In a capping operation for closing the nozzle of another ink discharge means using at least one of the cap means during the nozzle recovery operation for one ink discharge means and the closing movement means for moving to the closing position. It has a control means for controlling the operation of the cap moving means and the closing moving means.

  In the image forming apparatus according to the present invention, the control unit performs capping operation for closing the nozzle of the ink discharge unit that has completed the nozzle recovery operation using one of the cap units during the nozzle recovery operation for one ink discharge unit. As described above, the operation of the cap moving means and the closing movement means is controlled.

  In the image forming apparatus according to the present invention, during the nozzle recovery operation for one ink ejection unit, the control unit replaces the nozzle adjacent to the ink ejection unit that is performing the nozzle recovery operation with one of the cap units. It is characterized by controlling the operation of the cap moving means and the closing moving means so as to perform the capping operation to be closed.

  The image forming apparatus according to the present invention includes an empty discharge amount setting unit that sets an empty discharge amount during the nozzle recovery operation, and the control unit recovers the nozzle according to the empty discharge amount set by the empty discharge amount setting unit. It is characterized by changing the timing of the capping operation during operation.

  In the image forming apparatus according to the present invention, the control unit controls the operation of the cap moving unit and the closing moving unit so as not to execute the capping operation when the empty discharge amount is equal to or less than a predetermined value. .

  The present invention has a plurality of nozzles for ejecting ink, ejects ink from the plurality of nozzles toward the recording medium to form an image on the recording medium, and independently at least in the recording medium conveyance direction. Control of an image forming apparatus including a plurality of movable ink discharge means and a plurality of cap means capable of individually closing the nozzles of each ink discharge means, and performing ink idle discharge as a nozzle recovery operation of the ink discharge means The method is characterized in that during the nozzle recovery operation for one ink discharge means, the nozzles of another ink discharge means are closed using at least one of the cap means.

  In the control method of the image forming apparatus according to the present invention, the cap moving means that moves each cap means to a facing position that faces the nozzle and a retreat position that does not face the nozzle, and each cap member contacts the nozzle at the facing position. And a control unit for controlling the operation of the cap moving unit and the closing moving unit. During the nozzle recovery operation for one ink discharging unit, another ink discharging unit The cap moving means and the operation of the closing moving means are controlled by the control means so as to perform a capping operation in which the nozzle is closed using at least one of the cap means.

  In the control method of the image forming apparatus according to the present invention, the control unit closes the nozzle of the ink discharge unit that has finished the nozzle recovery operation using one of the cap units during the nozzle recovery operation for one ink discharge unit. It is characterized by controlling the operation of the cap moving means and the closing moving means so as to perform the capping operation.

  In the control method of the image forming apparatus according to the present invention, the control unit moves the nozzle adjacent to the ink discharge unit that is performing the nozzle recovery operation to the nozzle of the cap unit during the nozzle recovery operation for one ink discharge unit. It is characterized by controlling the operation of the cap moving means and the closing moving means so as to perform the capping operation to close with one.

  The image forming apparatus control method according to the present invention further includes an empty discharge amount setting unit that sets an empty discharge amount at the time of nozzle recovery operation, and the control unit corresponds to the empty discharge amount set by the empty discharge amount setting unit. The capping operation time during the nozzle recovery operation is changed.

  In the image forming apparatus control method according to the present invention, the control means controls the operation of the cap moving means and the closing moving means so as not to execute the capping operation when the idle discharge amount is equal to or less than a predetermined value. It is a feature.

  According to the present invention, in an image forming apparatus that performs idle ink discharge as a nozzle recovery operation of an ink discharge means, during the nozzle recovery operation for one ink discharge means, the nozzle of another ink discharge means is at least connected to the cap means. Since it is closed using one, it is possible to achieve low cost and space saving to prevent the surrounding head from being soiled by the mist of the ink ejected when performing the nozzle recovery operation for ejecting air in the cap. .

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. It is a block diagram which shows one form of a cap moving means. It is a block diagram which shows one form of the obstruction | occlusion moving means. FIG. 2 is a block diagram illustrating a configuration of a control system of the image forming apparatus according to the present invention. It is a figure which shows the standby state of a head part and a cap member. It is a figure which shows the state at the time of the printing by one ink discharge means. It is a figure which shows the state at the time of printing by all the ink discharge means. It is a figure which shows the standby state of a cap member, and the standby state of an ink discharge means. It is a figure which shows the state of the ink discharge means at the time of the nozzle recovery operation | movement with respect to the nozzle of the 1st color, and a cap member. It is a figure which shows the state of the ink discharge means at the time of the nozzle recovery operation | movement with respect to the nozzle of the 2nd color, and a cap member. It is a figure which shows the state of the ink discharge means at the time of the nozzle recovery operation | movement with respect to the nozzle of the 3rd color, and a cap member. It is a figure which shows the state of the ink discharge means at the time of the nozzle recovery operation | movement with respect to the nozzle of the 4th color, and a cap member. It is a flowchart which describes an example of the control content in performing nozzle recovery operation | movement with respect to the nozzle of all the head parts. It is a flowchart which describes an example of the content of control in performing nozzle recovery operation | movement with respect to the nozzle of arbitrary 1 color head parts. FIG. It is a flowchart which describes an example of the content of control in performing nozzle recovery operation | movement with respect to the nozzle of arbitrary 2 color head parts.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The ink jet type image forming apparatus shown in FIG. 1 is a line-type image forming apparatus, and includes an apparatus main body 1, a paper feed tray 2 that loads and feeds paper 10 as a recording medium, and a printed paper 10. A paper discharge tray 3 for discharging and stacking, a transport unit 4 for transporting the paper 10 from the paper feed tray 2 to the paper discharge tray 3, and a recording head for discharging ink droplets onto the paper 10 transported by the transport unit 4 for printing. An image forming unit 5 including a black head array (hereinafter referred to as a “black head portion”) 50a serving as an ink ejection means and a color head array (hereinafter referred to as a “color head portion”) 50b serving as an ink ejection means. A black cap member (hereinafter referred to as “black cap”) constituting a maintenance / recovery means for maintaining and recovering the black head portion 50a and the color head portion 50b of the image forming unit 5. ) 6a, a cap member for color (hereinafter referred to as "color cap") 6b, an ink supply system including a sub tank and a main tank (not shown) for supplying ink to the black head portion 50a and the color head portion 50b, and control means 500.

  The apparatus main body 1 includes front and rear side plates and stays (not shown), and the sheets 10 stacked on the sheet feed tray 2 are fed one by one to the transport unit 4 by a separation roller 21 and a sheet feed roller 22. Is done.

  The transport unit 4 includes a transport drive roller 41A, a transport driven roller 41B, and an endless transport belt 43 wound around these rollers 41A and 41B. A plurality of suction holes (not shown) are formed on the surface of the conveyor belt 43. A suction fan 44 for adsorbing the sheet 10 to the surface of the transport belt 43 is disposed below the transport belt 43. Conveying guide rollers 42A and 42B are respectively held on guides (not shown) on the conveying driving roller 41A and the conveying driven roller 41B, and are in contact with the conveying belt 43 by their own weight. A support member 148 is disposed on the back side of the conveyor belt 43. The transport belt 43 is supported by the support member 148 at a portion between the transport driving roller 41A and the transport driven roller 41B from below.

  The conveyance belt 43 rotates by the conveyance drive roller 41A being rotated by the conveyance belt drive motor 512 shown in FIG. 4, and the paper 10 is adsorbed onto the conveyance belt 43 by the action of the suction fan 44, thereby conveying the conveyance belt 43. It is conveyed by the circumferential movement of the belt 43. The transport driven roller 41 </ b> B and the transport guide rollers 42 </ b> A and 42 </ b> B are driven by the transport belt 43 to rotate.

  A paper discharge tray 3 for storing the paper 10 is provided on the downstream side of the transport unit 4. The paper discharge tray 3 includes a pair of side fences 31 that regulate the width direction of the paper 10 and an end fence 32 that regulates the front end of the paper 10.

  Above the transport unit 4, an image forming unit 5 including two head modules, a black head unit 50 a and a color head unit 50 b, which eject ink that is droplets to be printed on the paper 10 is disposed.

  In the black head portion 50a, a plurality of nozzles 57 and 58 for ejecting droplets of ink for one color (black K) are lined in the paper width direction with respect to the paper 10 conveyed by being sucked and held on the transport belt 43 The line-type recording heads are arranged in a line. The color head unit 50 b is a plurality of nozzles 51 to 56 that eject ink droplets of three colors (yellow Y, cyan C, and magenta M) onto the paper 10 that is sucked and held on the transport belt 43 and transported. Have line-type recording heads arranged in a line in the paper width direction. In the image forming unit 5, the colors are arranged in the order of yellow Y, cyan C, magenta M, and black K from the downstream side in the recording medium conveyance direction indicated by arrow X (left side in FIG. 1). The color order of the color head unit 50b is not limited to yellow Y, cyan C, and magenta M, but other secondary colors, gray ink, or the like is used, and the number of nozzles corresponding to the secondary color or the color head is used. A configuration in which the number of line-type recording heads in the section 50b is increased may be used.

  The black head portion 50a and the color head portion 50b are arranged adjacent to each other, and each ejects ink onto the paper 10 on the conveyance belt 43. The printing position shown in FIGS. Thus, the head is moved to the standby position shown in FIG. As the head part moving means, the black head part 50a and the color head part 50b may be moved in the vertical direction by a cam mechanism, respectively, or the black head part 50a and the color head part may be moved by using moving means composed of a belt and a pulley. This can be realized by making the head portion 50b movable in the vertical direction.

  The image forming unit 5 performs a nozzle recovery operation that performs idle ejection of ink from the nozzles of the heads that are not used for printing in order to prevent the ink in the openings of the nozzles 51 to 58 included in the heads from drying. It is configured. This nozzle recovery operation is performed in a state in which each head unit is moved upward from the printing position shown in FIGS. 1 and 7 to occupy the standby position shown in FIG. The nozzle recovery operation will be described later.

  The black cap 6a and the color cap 6b occupy positions facing the respective head portions, and close the nozzles 51 to 58 by contacting the respective recording heads at the respective facing positions. In the image forming unit 5, well-known flow paths, suction means, pressure chambers and the like connected to the black cap 6a and the color cap 6b, respectively, are arranged downstream of the black cap 6a and the color cap 6b. A blade member for wiping in close contact with the recording head surface is provided.

  As shown in FIGS. 2 and 3, the image forming apparatus includes a cap that moves the black cap 6 a and the color cap 6 b to a facing position facing the nozzles 51 to 58 of each head unit and a retracted position not facing the nozzle. The moving means 60A, 60B, the black cap 6a and the color cap 6b are moved to the closed position where the black head portion 50a and the nozzle of the color head portion 50b are in contact with the nozzles and moved to the closed position. 70B.

  The configuration of the cap moving means 60A for moving the black cap 6a and the closing movement means 70A will be described with reference to FIG. The cap moving means 60A rotates the pulleys 612 and 613, the belt 620 wound around the pulleys 612 and 613, a fixing member 616 for fixing the black cap 6a to a part of the belt 620, and the pulleys 612 and 613. A base member 611 that supports the black cap 6a and a maintenance movement motor 617A that is a driving unit that rotationally drives the pulley 612 are provided.

  The black cap 6a is configured to move in the belt moving direction when the maintenance movement motor 617A is actuated to rotate the pulley 612 and the belt 620 moves. In this embodiment, the belt 620 is disposed to the lower side of the color head unit 50b in the recording medium conveyance direction X adjacent to the conveyance black head unit 50a and the color head unit 50b, and the black cap 6a is slid in the horizontal direction in the drawing. Is configured to do. The moving range of the black cap 6a is set to a range from the retracted position shown in FIGS. 2 and 6 that does not face the nozzles 57 and 58 of the black head 50a to the position that faces the nozzles 51 and 52 of the color head section 50b. . The movement position of the black cap 6a is detected by detection sensors S1 to S5 arranged on the movement track of the fixed member 611. The position detected by the detection sensor S1 is a first facing position facing the nozzles 51 and 52 of the color head portion 50b, and the position detected by the detection sensor S2 is a second facing position facing the nozzles 53 and 54. The position detected by the detection sensor S3 is the third position facing the nozzles 55 and 56, and the position detected by the detection sensor S4 is the fourth position facing the nozzles 57 and 58 of the black head portion 50a. The positions at which the facing position is detected by the detection sensor S5 are detected as retracted positions that do not face the color head portion 50b and the black head portion 50a, respectively.

  One end 619A of a threaded shaft 619 serving as a drive shaft extending in the vertical direction in the drawing is screwed into one end 611a side of the base member 611. A gear 618 that meshes with a drive gear 617 that is rotationally driven by a maintenance movement motor 617B that is a stepping motor is fixed to the other end 619B of the shaft 619. The drive gear 617, the gear 618, the shaft 619, and the maintenance movement motor 617B constitute a closing movement means 70A.

  In the closing movement means 70A, when the maintenance movement motor 617B operates and the drive gear 617 rotates, the shaft 619 rotates via the gear 618 and the base member 611 moves in the vertical direction in the figure. The moving direction can be achieved by rotating the maintenance moving motor 617B in the forward and reverse directions. For example, when the maintenance movement motor 617B rotates forward, the black cap 6a can move to the facing position, and when the maintenance moving motor 617B rotates backward, the black cap 6a can move from the facing position to the closing position where the nozzle abuts against the nozzle. The position detection of the facing position and the closing position may be controlled by the number of pulses when the maintenance movement motor 617B is configured by a stepping motor, or when a stepping motor is not used, a separate sensor or the like is provided for detection. You may do it.

  The configuration of the cap moving means 60B that moves the color cap 6b and the closing movement means 70B will be described with reference to FIG. The cap moving means 60B rotates the pulleys 602 and 603, the belt 630 wound around the pulleys 602 and 603, a fixing member 601 for fixing the collar cap 6b to a part of the belt 630, and the pulleys 602 and 603. A base member 600 that supports the collar cap 6b and a maintenance movement motor 617C serving as a driving unit that rotationally drives the pulley 603 are provided.

  When the pulley 603 is rotationally driven by the operation of the maintenance movement motor 617C and the belt 630 moves, the collar cap 6b is moved in the belt movement direction. In this embodiment, the belt 630 is disposed in the direction adjacent to the black head portion 50a and the color head portion 50b, and is configured to slide the color cap 6b in the left-right direction in the drawing. The moving range of the color cap 6b is not opposed to the nozzles 51 to 56 of the color head portion 50b. FIGS. 6 and 12 are opposed to all the nozzles 51 to 56 of the color head portion 50b from the retracted position shown in FIGS. It is set as the range to the opposing position shown. The movement position of the collar cap 6b is detected by detection sensors S6 to S10 arranged on the movement track of the fixed member 601. The position detected by the detection sensor S6 is a retreat position that does not face any nozzle of the color head portion 50b, and the position detected by the detection sensor S7 is a fifth face position that faces the nozzles 51 and 52. The position detected in S8 detects the sixth counter position that faces the nozzles 51 to 54, and the position detected by the detection sensor S9 detects the seventh counter position that faces the nozzles 51 to 56, respectively.

  One end 610 </ b> A of a threaded shaft 610 serving as a drive shaft extending in the vertical direction in the drawing is screwed into one end portion 600 a side of the base member 600. A gear 609 that meshes with a drive gear 608 that is rotationally driven by a maintenance movement motor 617D that is a stepping motor is fixed to the other end 610B of the shaft 610. These driving gear 608, gear 609, shaft 610 and maintenance moving motor 617D constitute a closing moving means 70B.

  In the closing movement means 70B, when the maintenance movement motor 617D is activated and the drive gear 608 is rotated, the shaft 610 is rotated via the gear 609, whereby the base member 600 is moved in the vertical direction in the drawing. The moving direction can be achieved by rotating the maintenance moving motor 617D in the forward / reverse direction. For example, when the maintenance movement motor 617D rotates forward, the collar cap 6b can be moved from the facing position to the closed position where the nozzle abuts against the nozzle. The position detection of the facing position and the closed position may be controlled by the number of pulses when the maintenance moving motor 617D is configured by a stepping motor, or when a stepping motor is not used, a separate sensor or the like is provided for detection. You may do it.

An outline of the control unit 500 of the image forming apparatus will be described with reference to FIG.
The control means 500 is a well-known information processing apparatus such as a well-known personal computer equipped with a well-known CPU 501, ROM 502, RAM 503, NVRAM 504, which is a nonvolatile memory, and host interface (host I / F) 506.

  The control unit 500 moves the head drive control unit 508 and the head driver 509 for controlling the ink ejection operation of the recording heads of the black head unit 50a and the color head unit 50b, and the black head unit 50a and the color head unit 50b in the vertical direction. Head unit moving motor driving units 511A and 511B for driving the head unit moving motors 512A and 512B, which are driving units of the moving head unit moving unit, and at least the black cap 6a and the color cap 6b are moved in the vertical and horizontal directions. Head moving maintenance motor driving units 617A to 617D for driving maintenance moving motors 617A to 617D constituted by driving motors of the cap moving means 60A and 60B and the closing moving means 70A and 70B, and driving of the conveyance bell 43 To drive the conveyor belt drive motor 512 as a source The transport position of the paper 10 is determined by a transport belt drive unit 513, a suction motor drive unit 514 that drives a suction motor 515 that rotates the suction fan 44, an environmental sensor 521 that serves as an environment detection means for detecting environmental temperature and / or environmental humidity. A sheet sensor 522 for detection, an I / O port 516 for inputting detection signals from various sensors (not shown) including the detection sensors S1 to S9, and the like are provided. An operation panel 520 for inputting and displaying information necessary for the image forming apparatus is connected to the control unit 500. The operation panel 520 is provided with an empty discharge amount setting means 540 for setting an empty discharge amount during the head recovery operation.

  In this embodiment, the ROM 502 creates the relationship between the humidity and the empty discharge amount as a table at the time of design and stores it as a control sequence table. In this table, when the amount of ink ejected in the nozzle recovery operation for ejecting ink idly increases, the ink ejected idly into the black cap 6a and the color cap 6b may be scattered as mist and stain the surroundings. Therefore, the control for the black cap 6a and the color cap 6b during the idle ink discharge (nozzle recovery operation) is set such that the set value T is changed by the idle discharge amount setting means 540 with respect to the empty ink ejection amount. . That is, when the ink ejection amount during the ink recovery operation exceeds the set value T, there is a concern about contamination due to mist, so that the cap 6a or the cap 6 with respect to the nozzle adjacent to the nozzle of the head portion that ejects ink idly. If the ink discharge amount is less than the set value T when the closing operation (capping) is performed to close the nozzle in 6b, the occurrence of mist is less and the possibility of contamination is eliminated. The operation of each cap unit is controlled so that the nozzle 6 adjacent to the cap 6a or the cap 6b is not closed (capped).

  The set value T is stored in the ROM 502, and can be set so that it can be changed by the user by the idle discharge amount setting means 540 shown in FIG. The set value T is recorded in the nonvolatile memory 504, and may be set by a user operation on the operation panel 520 to change the closing operation (capping) at the time of idle ejection.

  When the control unit 500 and its CPU 501 perform a printing operation, the print data in the reception buffer included in the host I / F 506 is read and analyzed, and the ASIC 505 rearranges the data (in some cases, a part of the image processing). Process) to transfer the image data to the head drive controller 508. Conversion to bitmap data (print raster data), which is one of print data for image output, is performed by developing image data into bitmap data by a printer driver on the host side, and printing data bitmap data (print raster data). Data) is created, and then the print raster data is transferred to the control means 500.

  When the host I / F 506 receives print raster data, the head drive control unit 508 sends the dot pattern data (print raster data) to the head driver 509 as serial data in synchronization with the clock signal. A latch signal is sent to the head driver 509 at the timing.

  The head drive control unit 508 includes a ROM (can also be configured by the ROM 502) that stores pattern data of drive waveforms (drive signals), and a D / A converter that D / A converts the drive waveform data read from the ROM. A waveform generation circuit including an A converter and a drive waveform generation circuit including an amplifier and the like are included. The head driver 509 receives a clock signal from the head drive control unit 508 and serial data as image data, and a latch circuit that latches the register value of the shift register using a latch signal from the head drive control unit 508. A level conversion circuit (level shifter) that changes the output value of the latch circuit, an analog switch array (switch means) that is controlled to be turned on / off by the level shifter, and the like, and controls on / off of the analog switch array. As a result, a required drive waveform included in the drive waveform is selectively applied to the actuator means of the recording head of each of the head portions 50a and 50b to drive the recording head and print the image data to form a dot pattern. The head unit moving motor driving units 511A and 511B operate the head unit moving motors 512A and 512B during printing or nozzle recovery operation. The head maintenance movement motor driving unit 516 performs a maintenance movement motor 617A so as to move the black cap 6a to a position facing the nozzle of the head part that performs the idle ink ejection when the ink idle ejection operation is performed as the nozzle recovery operation. In addition, the maintenance movement motors 617C and 617D are operated so that the nozzles adjacent to the nozzles that perform ink ejection are closed by the color cap 6b.

  FIG. 5 shows a standby state in which all the nozzles 51 to 58 of each head unit are closed (capped) with the black cap 6a and the color cap 6b in the power saving mode when the power is turned on or when printing is not performed for a certain time. Show. FIG. 6 shows the state of each head unit and each cap 6a, 6b during monochrome printing using the black head unit 50a. FIG. 7 shows each head unit and each unit during color printing by the black head unit 50a and the color head unit 50b. The state of the caps 6a and 6b is shown. Then, there are three cases shown in FIGS. 5, 6, and 7 as the state of the head portion when the controller 500 instructs the ink ejection (nozzle recovery).

  When printing is started from the standby state shown in FIG. 5, whether or not maintenance is necessary is determined by the standing time in the capping state. Both black and color are left for a preset time and printing is performed using the black head portion 50a and the color head portion 50b during printing. When performing color printing shown in FIG. 7, maintenance is performed on both head portions. (Nozzle recovery operation such as idling and wiping) must be performed. Further, when the monochrome printing shown in FIG. 6 is performed from the standby state of FIG. 5, maintenance (nozzle recovery operation) may be performed on the black head portion 50a.

  FIG. 6 shows a state immediately after the end of monochrome printing. When color printing is performed next, when the leaving time of the color head unit 50b capped with the color cap 6b is longer than the set time, the maintenance of the color head unit 50b is performed. (Nozzle recovery) needs to be performed. In this state, when the mode is shifted to the power saving mode by leaving for a certain time, the black head portion 50a is in the capping state shown in FIG. 5 with the black cap 6a. The black head part 50a is in a state immediately after printing and the nozzle surface is in a dischargeable state, so there is basically no need for maintenance, but maintenance is instructed due to abnormal discharge such as nozzle down or periodic maintenance. Sometimes it is done.

  The state shown in FIG. 7 is a state immediately after the end of the color printing, and shifts to the power saving mode when left for a fixed time and shifts to the standby state (blocked state) shown in FIG. Before the transition, all the nozzles 51 to 56 of the color head portion 50b are in a state immediately after color printing and maintain a dischargeable state, so that basically no maintenance is required. However, there is a case where maintenance is instructed for the nozzles of an arbitrary head due to discharge abnormality such as nozzle down or periodic maintenance. Hereinafter, the recovery operation of each head unit will be described.

  8 to 12 are explanatory diagrams of the capping operation at the time of ink ejection (nozzle recovery operation). FIG. 8 shows a standby state in which printing is not performed. The black cap 6a and the color cap 6b are released from the closed state shown in FIG. 5 and occupy the standby position. In this example, the nozzles 51 and 52 are for yellow Y, the nozzles 53 and 54 are for cyan C, the nozzles 55 and 56 are for magenta M, and the nozzles 57 and 58 are for black K.

  FIG. 13 and the flowcharts shown in FIGS. 8 to 12 show the control contents of the control means 500 when the ink is discharged as a nozzle recovery operation for all the colors, that is, all the nozzles 51 to 58 from such a state. It explains using.

  When the nozzle recovery operation is started, the control unit 500 determines in step ST1 whether each head unit is located at a standby position shown in FIG. 8 where nozzle maintenance is possible. If each head unit is not in the standby position, the head unit moving motors 512A and 512B are actuated in step ST2 to move each head unit to the standby position. If the position is occupied, the process proceeds to step ST3.

  After moving to the standby position, whether or not the black cap 6a has occupied the first facing position P1 facing the nozzles 51 and 52 located at the end of the color head portion 50b as shown in FIG. 9 in step ST3. Whether or not there is an output from the detection sensor S1 is determined. Here, when there is no output from the detection sensor S1, it is assumed that the black cap 6a has not reached the first standby position P1, and the black cap 6a is moved to the first facing position P1 in step ST4. Accordingly, the maintenance movement motor 617A is actuated in the direction opposite to that at the time of movement to the standby position to move to the cap P1 position. When the black cap 6a occupies the first facing position P1, the process proceeds to step ST5, a nozzle recovery operation is performed by empty ink ejection to the yellow Y nozzles 51 and 52, and the process proceeds to step ST6.

  In step ST6, as shown in FIG. 10, the maintenance moving motor 617A is operated to move the black cap 6a to the second facing position P2 facing the nozzles 53 and 54 of the magenta M. Further, in order to prevent the nozzles 51 and 52 that have completed the nozzle recovery operation from being smeared with mist-like ink generated when ink is ejected from the nozzles 53 and 54, the color cap 6b is closed. The maintenance movement motors 617C and 617D are actuated to move the color cap 6b to a position facing the nozzles 51 and 52, and the color cap 6b is moved up to a closed position where the color cap 6b contacts the nozzles 51 and 52 at the facing position. To do.

  In step ST7, the black cap 6a occupies the second facing position, and the color cap 6b occupies the closed position where it abuts against the nozzles 51 and 52, and outputs from the detection sensor S2, the detection sensor S7, and the maintenance movement motor 617B. , 617D, and the like. When each cap occupies the state shown in FIG. 10, in step ST9, a nozzle recovery operation is performed by empty ink ejection to the cyan C nozzles 53 and 54, and the process proceeds to step ST10.

  In step ST10, as shown in FIG. 11, the maintenance movement motor 617A is actuated to move the black cap 6a to the third facing position P3 facing the magenta M nozzles 55 and 56, and the ink is ejected from the nozzles 55 and 56. In order to prevent the nozzles 51 to 54 (particularly the nozzles 53 and 54) that have completed the nozzle recovery operation from being contaminated by the mist-like ink generated when the ink is discharged in an idle state, maintenance is performed so as to close the cap with the color cap 6 b. The moving motor 617C is operated to move the color cap 6b to a position facing the nozzles 51 to 54. In this case, since the collar cap 6b is already in the raised closed position, the maintenance moving motor 617D does not operate, and only the maintenance moving motor 617C is operated to slide the collar cap 6b in the lateral direction. However, in this case, since the color cap 6b moves while being in contact with the nozzles 51 to 54, the maintenance movement motor 617D is operated from the closed position with the nozzles 51 and 52 when there is a possibility of ink adhering to the nozzles. The color cap 6b is once lowered to the facing position, the maintenance moving motor 617C is operated to move to the facing position with the nozzles 53 and 54, and then the color cap 6b is again moved to the nozzle 53 at the facing position. , 54 may be controlled by the maintenance movement motor 617D so as to move up to a position where it comes into contact with.

  In step ST10, the black cap 6a occupies the third facing position and the color cap occupies the closed position where it abuts against the nozzles 51 to 54, the outputs from the detection sensors S3 and S8, the maintenance movement motor 617B, It is determined from the number of steps of 617D. If each cap occupies the state shown in FIG. 11, the process proceeds to step ST11, a nozzle recovery operation is performed by empty ink ejection to the magenta nozzles 55 and 56, and the process proceeds to step ST12.

  In step ST12, as shown in FIG. 12, the maintenance movement motor 617A is driven to move the black cap 6a to the fourth facing position P4 facing the black K nozzles 57 and 58. Further, in order to prevent the nozzles 51 to 56 (particularly the nozzles 55 and 56) that have completed the nozzle recovery operation from being stained by the mist-like ink that is generated when ink is ejected from the nozzles 57 and 58, the color ink is used. In order to close the nozzles 51 to 56 with the cap 6b, the maintenance moving motor 617C is operated to move the collar cap 6b to a position facing the nozzles 51 to 56. In this case, since the collar cap 6b is already in the raised closed position, the maintenance movement motor 617D does not operate, and the maintenance movement motor 617C operates to slide the collar cap 6b in the lateral direction.

  In step ST13, the black cap 6a occupies the fourth facing position, and the color cap 6b occupies the closed position where it abuts against the nozzles 51 to 56, and outputs from the detection sensors S4 and S9 and the maintenance movement motor 617B. , 617D, and the like. When the detection sensors S4 and S9 detect that the black cap 6a and the color cap 6b have moved to the positions shown in FIG. 12, the process proceeds to step ST14. In step ST14, ink is ejected to the black K nozzles 57 and 58 to perform a nozzle recovery operation, and this control is completed.

  In this way, all the black head portions 50a and the color head portions 50b are idlely discharged. By providing the black cap 6a with a suction mechanism and a wiping mechanism, pressure maintenance or Maintenance operations (nozzle recovery operation) such as suction maintenance and wiping may be performed. The above is the description of the operation when performing idle ejection for all colors.

  In this way, in the image forming apparatus that performs idle ink ejection as the nozzle recovery operation of the black head unit 50a and the color head unit 50b, during the nozzle recovery operation for the nozzle of one head unit, Alternatively, the nozzle that has already completed the nozzle recovery operation adjacent to the nozzle performing the nozzle recovery operation is closed using the existing color cap 6b, so that the nozzle recovery operation for discharging ink is performed. It is possible to achieve low cost and space-saving prevention of the surrounding head (nozzles) from being contaminated by the mist of the ink ejected during the operation.

  When the idle ejection with respect to the nozzles 51 to 58 of all the head parts is completed, the head parts 50a and 50b stand by at the printing position shown in FIG. In the case of printing only in black, as shown in FIG. 6, the printer waits in a state where the color head portion 50b is closed with the color cap 6b. Alternatively, when the post-printing idle discharge is performed in which the operation is terminated after the nozzle recovery operation in which the nozzles 51 to 58 are idle after printing is performed, as shown in FIG. The black head portion 50a and the color head portion 50b may be closed with the black cap 6a and the color cap 6b, and the operation may be terminated.

Next, the contents of control in the case where the nozzle recovery operation is performed by performing idle ejection on a nozzle of any one of a plurality of colors will be described with reference to FIG.
Here, an arbitrary color nozzle is n nozzles, a nozzle adjacent to the right side of the n nozzles is n + 1 nozzles, and a nozzle adjacent to the left side is n-1 nozzles. For example, in the configuration of the head unit 50b, when n nozzles are yellow nozzles 51 and 52, there are no n-1 nozzles adjacent to the left side, n + 1 nozzles are adjacent cyan nozzles 53 and 54, and n nozzles are magenta. In the case of the nozzles 53 and 54, the n-1 nozzle is the cyan nozzle 53 and 54, and the n + 1 nozzle is the nozzle 57 and 58 of the black head portion 50a.

  When the head recovery operation is started, the control unit 500 determines in step ST21 that all the head units are located at the standby position where the head maintenance is possible. If it is not in the standby position, the head part moving motors 512A and 512B are operated in step ST22 to move the head parts 50a and 50b from the printing position to the standby position shown in FIG. When all the head portions 50a and 50b are moved to the standby position, in step ST23, it is determined whether or not the cap is at the position facing the n nozzle by the output of the detection sensor. In ST24, the corresponding maintenance movement motor is operated so as to move to a position facing the n-nozzle that performs ink empty ejection (nozzle recovery operation).

  In step ST25, it is determined whether or not n-1 nozzles (nozzles on the left side) are present. If n-1 nozzles are present, capping using a color cap is performed in step ST26. In step ST27, it is determined whether or not capping is performed on the n-1 nozzle. If capping is performed, in step ST28, the idle discharge (nozzle recovery operation) from the n nozzle to the black cap 6a is performed. To be implemented.

  Next, in step ST29, it is determined whether or not there are n + 1 nozzles. If there are n + 1 nozzles, the process proceeds to step ST30, where the empty discharge amount P from the n nozzles is measured, and the measurement result is determined in step ST31. A set value T is set in the ROM 502 in advance. This set amount T is the amount of ink that is ejected in the mist when the n nozzles perform the ejecting operation and affects the adjacent head.

  In step ST31, if the empty discharge amount P per one time from the n nozzles exceeds the set value T, there is a possibility that mist has already adhered to the adjacent nozzles. Therefore, in step ST32, the cap faces the n + 1 nozzle. The corresponding maintenance movement motor is operated to move to the position, and the wiping operation is performed in step ST33. When the empty discharge amount P from the n nozzles is less than the set value T, it is determined that no mist is generated by the empty discharge ink, and the wiping process to the n + 1 nozzle is not performed, and this control is finished.

  For example, when n nozzles are yellow nozzles 51 and 52, ink is ejected from the nozzles 51 and 52 to the black cap 6a at the cap position P1 shown in FIG. At this time, since there is no nozzle or head corresponding to the n-1 nozzle, capping of the n-1 nozzle is not performed. When the idle discharge amount P of the nozzles 51 and 52 is equal to or larger than the set value T, the black cap 6a moves to the cap position P2 and wipes the nozzles 53 and 54 corresponding to the adjacent n + 1 nozzles with the black cap 6a as shown in FIG. Implement and finish.

  When the n nozzles are the nozzles 57 and 58 of the black head portion 50a, as shown in FIG. 12, ink empty ejection of the nozzles 57 and 58 is performed at the cap position P4. In that case, since the nozzles 55 and 56 which are n-1 nozzles adjacent to the left side exist, the nozzles below the n-1 nozzle are blocked by capping by the color cap 6b. In the present embodiment, since there is no n + 1 nozzle adjacent to the right side of the nozzles 57 and 58, the wiping process for the n + 1 nozzle is not executed, and this control ends.

Next, the contents of control in the case where the nozzle recovery operation is performed by performing the idle ejection for the nozzles of any two colors among the plurality of colors will be described with reference to FIG.
In FIG. 15, steps ST41 to ST48 are the same as the processing from step ST21 to step ST28 already described in FIG. 14, and are omitted here. Implementation of idle discharge will be described. Further, when the other nozzles are adjacent to the n nozzles, the number is n + 1, and there is a possibility of sequentially reaching n + 2 and n + 3.

  For example, when n is yellow nozzles 51 and 52, n + 1 corresponds to cyan nozzles 53 and 54, n + 2 corresponds to magenta nozzles 55 and 56, and n + 3 corresponds to black nozzles 57 and 58. Since which nozzle is ejected differently depends on the use state of the apparatus, one of the two color nozzles ejected idly is represented by n, and the second head array is represented by n + X.

  In step ST48 of FIG. 15, when ink is ejected idly from the n nozzles (nozzle recovery operation), the control means 500 takes in the position of the second n + X nozzle in step ST49, and X ≠ 1 in step ST50. That is, it is determined whether the n + X nozzle is adjacent to the n nozzle. If the nozzle is not adjacent to the n nozzle, it is necessary to determine whether or not there is contamination due to the mist adhering to the n + 1 nozzle due to the n nozzle idle discharge before performing the n + X nozzle idle discharge in step ST53. . For this reason, if X ≠ 1 in step ST50, the process proceeds to step ST59, where the idle discharge amount P from the n nozzle is measured, and the measurement result is determined in step S60. In step ST60, if the empty discharge amount P per one time from the n nozzles exceeds the set value T, there is a possibility that mist has already adhered to the adjacent nozzles, so in step ST12 the cap is opposed to the n + 1 nozzles. The corresponding maintenance movement motor is operated to move to the position, and the wiping operation is performed in step ST62.

  On the other hand, if X ≠ 1, the cap is moved to a position facing the n + X nozzle in step ST50, and whether the cap is in a position facing the n + X nozzle is determined based on the output of the detection sensor in step ST51. To do. If the opposite position is occupied, in step ST52, the n + X-1 nozzle is capped with a cap and closed, and then in step ST53, the n + X head array is ejected idly.

  In step ST54, it is determined whether or not n + X + 1 is present, and in step ST55, the amount of idle discharge P (cumulative or per-time?) Is measured from the n + X nozzle. If the empty discharge amount P from the n + X nozzle exceeds the set value T in ST56, there is a possibility that the mist has already adhered to the adjacent nozzle. Therefore, in step ST57, the position where the cap faces n + X + 1 The corresponding maintenance movement motor is actuated to move to, and in step ST58, the wiping operation is performed on the n + X + 1 nozzles, and this control is finished.

  For example, when the nozzles for wiping are designated as yellow nozzles 51 and 52 and magenta nozzles 55 and 56, the cap is moved to a position opposite to the yellow nozzles 51 and 52. Here, since there is no n-1 nozzle on the left side of the nozzles 51 and 52, there is no need for capping the n-1 nozzle.

  After the idle ejection of the nozzles 51 and 52 is completed, the n + Xth nozzle is idlely ejected. Since the magenta nozzles 55 and 56 correspond to X = 2, the presence or absence of wiping of the cyan nozzles 53 and 54 that are n + 1 nozzles is determined from the idle discharge amount P of the nozzles 51 and 52. Then, when the idle discharge of the set value T or more has been performed, the cyan nozzles 53 and 54 are wiped. After the wiping is completed, the color cap 6b is moved to a position opposite to the magenta nozzles 55 and 56, and the cyan nozzles 54 and below, that is, the nozzles 51 to 54 are closed by capping, and the magenta nozzles 55 and 56 are ejected with no ink. After the idle discharge from the magenta nozzles 55 and 56, if the empty discharge amount from the nozzles 55 and 56 is equal to or greater than the set value T, the black nozzles 57 and 58 are wiped. The above is an example in the case of performing the idle ejection of ink of any two color nozzles.

  Similarly, there is a case where ink is ejected from any of the three colors of nozzles (nozzle recovery operation), but the control content is expanded to the control content in the case of two colors in FIG. Similarly, when the nozzles provided in the head portion are configured to eject ink of four or more colors, it is possible to cope with the problem by expanding the control contents in the case of two colors in FIG.

6a, 6b Cap means 10 Recording medium 50a, 50b Ink ejection means 51-58 Multiple nozzles 60A, 60B Cap moving means 70A, 70B Blocking moving means 500 Control means 540 Empty discharge amount setting means P Empty discharge amount T Set value X Recording Media transport direction

Japanese Patent No. 3670428 JP 2001-113714 A JP 2008-307797 A JP 2006-96017 A JP 2009-18519 A JP 2009-166357 A Japanese Patent No. 2771545 JP 2008-213216 A

Claims (12)

Has a plurality of nozzles for ejecting ink, and ejects ink from the plurality of nozzles toward the recording medium to form an image on the recording medium, and each can move independently in at least the recording medium conveyance direction In an image forming apparatus that includes a plurality of ink discharge means and a plurality of cap means that can individually close the nozzles of each ink discharge means, and performs idle ink discharge as a nozzle recovery operation of the ink discharge means.
An image forming apparatus characterized in that, during a head recovery operation for one ink ejection unit, a nozzle of another ink ejection unit is closed using at least one of the cap units. Cap moving means for moving each cap means to a facing position facing the nozzle and a retracted position not facing the nozzle;
A closing movement means for moving each cap member to a closing position where the cap member contacts and closes the nozzle at the facing position;
During the head recovery operation for one ink ejection means, the cap moving means and the closing movement means are configured to perform a capping operation for closing the nozzle of another ink discharging means using at least one of the cap means. 2. The image forming apparatus according to claim 1, further comprising control means for controlling operation.   The control means performs the capping operation to block the nozzle of the ink discharge means that has finished the head recovery operation using one of the cap means during the head recovery operation for one ink discharge means. The image forming apparatus according to claim 2, wherein the operation of the moving unit and the closing moving unit is controlled.   The control unit performs a capping operation of closing a nozzle adjacent to the ink discharge unit that is performing the head recovery operation using one of the cap units during the head recovery operation for one ink discharge unit. The image forming apparatus according to claim 2, wherein the operation of the cap moving unit and the closing moving unit is controlled. An empty discharge amount setting means for setting an empty discharge amount during the head recovery operation;
5. The image according to claim 2, wherein the control unit changes the timing of the capping operation during the head recovery operation according to the empty discharge amount set by the empty discharge amount setting unit. Forming equipment.   The said control means controls the action | operation of the said cap moving means and the said obstruction | occlusion moving means so that capping operation | movement is not performed when the said idle discharge amount is below a predetermined value. Image forming apparatus. Has a plurality of nozzles for ejecting ink, and ejects ink from the plurality of nozzles toward the recording medium to form an image on the recording medium, and each can move independently in at least the recording medium conveyance direction And a plurality of cap means capable of individually closing the nozzles of each ink discharge means, and a method of controlling an image forming apparatus that performs idle ink discharge as a nozzle recovery operation of the ink discharge means In
A method of controlling an image forming apparatus, wherein a nozzle of another ink discharge means is closed using at least one of the cap means during a head recovery operation for one ink discharge means. Cap moving means for moving each cap means to a facing position facing the nozzle and a retracted position not facing the nozzle;
A closing movement means for moving each cap member to a closing position where the cap member contacts and closes the nozzle at the facing position;
Control means for controlling the operation of the cap moving means and the closing movement means;
Actuation of the cap moving means and the closing movement means so as to perform a capping operation in which the nozzle of another ink discharging means is closed using at least one of the cap means during a head recovery operation for one ink discharging means. 8. The method of controlling an image forming apparatus according to claim 7, wherein the control unit controls the image forming apparatus.   The control means performs the capping operation to block the nozzle of the ink discharge means that has finished the head recovery operation using one of the cap means during the head recovery operation for one ink discharge means. 9. The method of controlling an image forming apparatus according to claim 8, wherein the movement unit and the operation of the closing movement unit are controlled.   The control unit performs a capping operation of closing a nozzle adjacent to the ink discharge unit that is performing the head recovery operation using one of the cap units during the head recovery operation for one ink discharge unit. The image forming apparatus control method according to claim 8, wherein the operation of the cap moving unit and the closing moving unit is controlled. An empty discharge amount setting means for setting an empty discharge amount during the head recovery operation;
11. The image according to claim 8, 9 or 10, wherein the control means changes the timing of the capping operation during the head recovery operation according to the empty discharge amount set by the empty discharge amount setting means. Control method of forming apparatus.   12. The control unit according to claim 11, wherein the control unit controls the operation of the cap moving unit and the closing moving unit so as not to execute a capping operation when the idle discharge amount is equal to or less than a predetermined value. A method for controlling an image forming apparatus.

Images