JP5000383B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus, and more particularly, to an image forming apparatus including a recording head that discharges droplets and a maintenance mechanism thereof.

  As an image forming apparatus such as a printer, a facsimile machine, a copying machine, and a multifunction machine of these, for example, a liquid discharge apparatus including a recording head composed of a liquid discharge head that discharges liquid droplets is used. However, the material is not limited, and a recording medium, a recording medium, a transfer material, a recording paper, and the like are also used synonymously.) Printing, printing, and printing are also used synonymously).

  The image forming apparatus means an apparatus for forming an image by discharging a liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. The term “not only” means not only giving an image having a meaning such as a character or a figure to a medium but also giving an image having no meaning such as a pattern to the medium. Further, the liquid is not limited to the recording liquid and ink, and is not particularly limited as long as it is a liquid capable of forming an image. Further, the liquid discharge device means a device that discharges liquid from the liquid discharge head.

  An image forming apparatus that includes such a liquid ejecting apparatus and forms an image includes a maintenance / recovery mechanism that maintains and recovers the performance of a recording head that ejects liquid (hereinafter referred to as “ink”).

  This head maintenance / recovery mechanism (apparatus) includes a cap (cap member) that seals the nozzle surface (surface on which droplets are discharged) of the head. Further, an operation of sucking ink filled in the head from the nozzle by a suction means such as a suction pump communicating with the cap (head suction or nozzle suction), a wiper blade using an elastic member such as rubber ( Wiping operation of the head surface by a wiper member), and empty discharge operation (or preliminary discharge operation) for discharging ink so as not to contribute to image formation and discharging thickened ink and mixed color ink in the nozzle hole and in the vicinity of the entrance. Etc.) to remove bubbles, thickened ink, adhering dust, etc. in the liquid chamber, and perform an operation of maintaining a state where stable droplet discharge can be performed.

  Here, in the operation of wiping the nozzle surface after the head suction operation described above, if the wiping operation for wiping the nozzle surface is performed, the ink attached to the wiping member is scattered around due to the restoring deformation of the tip of the wiping member, and various There is a concern that it may be a cause of various discharge failures.

Accordingly, various proposals have been made to meet such demands, and as described in Patent Document 1, wiping without wiping the nozzle surface with the wiper member is performed, and ink adhering to the tip of the wiper member is scattered. Has been done to reduce.
JP 2005-119213 A

Further, as described in Patent Documents 2 and 3, etc., the relative movement speed between the wiper member and the nozzle surface is reduced immediately before the nozzle surface is wiped off.
JP 2003-191482 A JP 2003-341080 A

  By the way, since the ink needs to be quickly dried by increasing the recording speed of the image forming apparatus, a pigment-based ink having high viscosity (5 cP or more is defined as high viscosity) is used. . Therefore, the nozzle surface wiping method described in Patent Document 1 described above is effective in reducing ink scattering when wiping the nozzle surface, but when wiping high viscosity ink, The ink that wraps around the side surface on the wiping end side gradually accumulates while maintaining a certain viscosity, and the deposition gradually proceeds to a place that is out of the wiping area.

  If this deposit is sufficiently dried and solidified, this deposit will not hang down and will not cause any problems. However, depending on the operating conditions of the image forming apparatus, this deposit may not be completely dried. In some cases, it remains in a muddy state with high viscosity, and it has been confirmed that it hangs down due to vibration during movement of the carriage. In such a state, the sagging liquid deposit gradually advances downward, and there is a problem that it may eventually come into contact with the paper surface (the surface of the medium on which the liquid droplets are discharged) and become contaminated. found.

  The present invention has been made in view of the above problems, and an object of the present invention is to prevent the paper surface from being soiled by deposits that hang down downward with a high viscosity in an apparatus that performs a wiping operation that does not wipe up to the nozzle end surface.

In order to solve the above problems, an image forming apparatus according to the present invention provides:
A recording head having nozzles for discharging droplets;
A cap member for capping the nozzle surface of the recording head, a maintenance and recovery mechanism in which a wiper member for wiping the nozzle surface of the recording head is disposed;
Before Symbol a first wiping operation without Kira wiping to the other end side from the one end side of the nozzle face of the recording head in the wiper member, to the other end side of the nozzle surface from the one end of the recording head by the wiper member and a control means for controlling to I rows and a second wiping operation as possible wiping, a,
The control means performs control to perform the first wiping operation when the number of printed sheets per predetermined time is equal to or less than a preset threshold value, and to perform the second wiping operation when exceeding the threshold value,
The number of printed sheets per predetermined time is the number of printed sheets in the elapsed time from when the previous wiping operation was performed to immediately before the current wiping operation .

An image forming apparatus according to the present invention includes:
A recording head having nozzles for discharging droplets;
A cap member for capping the nozzle surface of the recording head, a maintenance and recovery mechanism in which a wiper member for wiping the nozzle surface of the recording head is disposed;
A first wiping operation in which the wiper member does not wipe the nozzle surface of the recording head from one end side to the other end side; and the wiper member wipes the nozzle surface of the recording head from one end side to the other end side. Control means for performing control to perform the second wiping operation for cutting,
The control means performs control to perform the first wiping operation when the number of printed sheets per predetermined time is equal to or less than a preset threshold value, and to perform the second wiping operation when exceeding the threshold value,
The number of printed sheets per predetermined time is an average of a plurality of printed sheets over the elapsed time from the previous wiping operation to immediately before the current wiping operation .

An image forming apparatus according to the present invention includes:
  A recording head having nozzles for discharging droplets;
  A cap member for capping the nozzle surface of the recording head, a maintenance and recovery mechanism in which a wiper member for wiping the nozzle surface of the recording head is disposed;
  A first wiping operation in which the wiper member does not wipe the nozzle surface of the recording head from one end side to the other end side; and a third wiping operation in which the wiper member wipes the side surface of the recording head on the other end side. Control means for performing control to perform
  The control means is configured to perform the first wiping operation when the number of printed sheets per predetermined time is equal to or less than a preset threshold value, and to perform the third wiping operation subsequent to the first wiping operation when the threshold value is exceeded. And
  The number of printed sheets per predetermined time is the number of printed sheets in the elapsed time from the previous wiping operation to immediately before the current wiping operation.
The configuration.

An image forming apparatus according to the present invention includes:
A recording head having nozzles for discharging droplets;
A cap member for capping the nozzle surface of the recording head, a maintenance and recovery mechanism in which a wiper member for wiping the nozzle surface of the recording head is disposed;
A first wiping operation in which the wiper member does not wipe the nozzle surface of the recording head from one end side to the other end side; and a third wiping operation in which the wiper member wipes the side surface of the recording head on the other end side. Control means for performing control to perform
The control means is configured to perform the first wiping operation when the number of printed sheets per predetermined time is equal to or less than a preset threshold value, and to perform the third wiping operation subsequent to the first wiping operation when the threshold value is exceeded. And
The number of printed sheets per predetermined time is an average of a plurality of printed sheets over the elapsed time from the previous wiping operation to immediately before the current wiping operation .

By the present invention lever, that the paper is soiled by sediments deposited by wiping operation not to cut-out wiping it can be prevented.

  According to the image forming apparatus of the present invention, the first wiping operation is performed in which the wiper member does not wipe the nozzle surface of the recording head from one end side to the other end side, and the first wiping operation is performed under a predetermined condition. Instead of the wiping operation, the second wiping operation for wiping the nozzle surface of the recording head from the one end side to the other end side with the wiper member is performed, so that the deposit deposited by the first wiping operation hangs down without being completely dried. It can be removed by the second wiping operation before coming, and the paper surface can be prevented from being soiled by deposits.

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, an example of an image forming apparatus according to the present invention will be described with reference to FIGS. FIG. 1 is an explanatory side view for explaining the overall configuration of the image forming apparatus, and FIG. 2 is an explanatory plan view of a main part of the apparatus.
This image forming apparatus is a serial type image forming apparatus, and a carriage 33 is slidable in the main scanning direction by main and slave guide rods 31 and 32 which are guide members horizontally mounted on the left and right side plates 21A and 21B of the apparatus main body 1. It is held and moved and scanned in the direction indicated by the arrow (carriage main scanning direction) in FIG. 2 via a timing belt by a main scanning motor (not shown).

  The carriage 33 is provided with recording heads 34a and 34b (which are liquid ejection heads according to the present invention for ejecting ink droplets of yellow (Y), cyan (C), magenta (M), and black (K). When not distinguished, it is referred to as “recording head 34”). A nozzle row composed of a plurality of nozzles is arranged in the sub-scanning direction orthogonal to the main scanning direction, and is mounted with the ink droplet ejection direction facing downward.

  Each of the recording heads 34 has two nozzle rows. One nozzle row of the recording head 34a has black (K) droplets, the other nozzle row has cyan (C) droplets, and the recording head 34b has one nozzle row. One nozzle row ejects magenta (M) droplets, and the other nozzle row ejects yellow (Y) droplets.

  Further, the carriage 33 is equipped with head tanks 35a and 35b (referred to as “head tank 35” when not distinguished) for supplying ink of each color corresponding to the nozzle rows of the recording head 34. The head tank 35 includes recording liquid cartridges 10y, 10m, 10c, and 10k that are detachably attached to the cartridge loading unit 4 and supply recording liquids of the respective colors via the supply tubes 36 of the respective colors by the supply pump unit 5. Is replenished.

  On the other hand, as a paper feeding unit for feeding the papers 42 stacked on the paper stacking unit (pressure plate) 41 of the paper feeding tray 2, a half-moon roller (feeding) that separates and feeds the papers 42 one by one from the paper stacking unit 41. A separation pad 44 made of a material having a large friction coefficient is provided facing the paper roller 43) and the paper feed roller 43, and the separation pad 44 is urged toward the paper feed roller 43 side.

  In order to feed the paper 42 fed from the paper feeding unit to the lower side of the recording head 34, a guide member 45 for guiding the paper 42, a counter roller 46, a transport guide member 47, and a tip pressure roller. And a holding belt 48 which is a conveying means for electrostatically attracting the fed paper 42 and conveying it at a position facing the recording head 34.

  The transport belt 51 is an endless belt, and is configured to wrap around the transport roller 52 and the tension roller 53 and circulate in the belt transport direction (sub-scanning direction). Further, a charging roller 56 that is a charging unit for charging the surface of the transport belt 51 is provided. The charging roller 56 is disposed so as to come into contact with the surface layer of the transport belt 51 and to rotate following the rotation of the transport belt 51. The transport belt 51 rotates in the belt transport direction of FIG. 2 when the transport roller 52 is rotationally driven through timing by a sub-scanning motor (not shown).

  Further, as a paper discharge unit for discharging the paper 42 recorded by the recording head 34, a separation claw 61 for separating the paper 42 from the conveying belt 51, a paper discharge roller 62, and a spur 63 that is a paper discharge roller. And a paper discharge tray 3 below the paper discharge roller 62.

  A duplex unit 71 is detachably mounted on the back surface of the apparatus body 1. The duplex unit 71 takes in the paper 42 returned by the reverse rotation of the conveyance belt 51, reverses it, and feeds it again between the counter roller 46 and the conveyance belt 51. The upper surface of the duplex unit 71 is a manual feed tray 72.

  Further, as shown in FIG. 2, a maintenance / recovery mechanism 81 for maintaining and recovering the state of the nozzles of the recording head 34 is disposed in the non-printing area on one side of the carriage 33 in the scanning direction. The maintenance / recovery mechanism 81 includes cap members (hereinafter referred to as “caps”) 82a and 82b (hereinafter referred to as “caps 82” when not distinguished from each other) for capping the nozzle surfaces of the recording head 34, and nozzle surfaces. A wiper member (wiper blade) 83 for wiping the liquid, an empty discharge receiver 84 for receiving liquid droplets when performing empty discharge for discharging liquid droplets that do not contribute to recording in order to discharge the thickened recording liquid, A wiper cleaner portion 85 that is integrally formed with the idle discharge receiver 84 and is a cleaning member for removing ink attached to the wiper blade 83, and a wiper cleaner 86 that presses the wiper blade 83 toward the wiper cleaner 85 when the wiper blade 83 is cleaned. And a carriage lock 87 for locking the carriage 22. A waste liquid tank 100 for storing waste liquid generated by the maintenance recovery operation is mounted on the lower side of the head maintenance recovery mechanism 81 in a replaceable manner with respect to the apparatus main body.

  In addition, as shown in FIG. 2, in the non-printing area on the other side in the scanning direction of the carriage 33, idle discharge is performed to discharge liquid droplets that do not contribute to recording in order to discharge the recording liquid thickened during recording or the like. An empty discharge receiver 88 for receiving the liquid droplets at the time is disposed, and the empty discharge receiver 88 is provided with an opening 89 along the nozzle row direction of the recording head 34.

  In this image forming apparatus configured as described above, the sheets 42 are separated and fed one by one from the sheet feed tray 2, and the sheet 42 fed substantially vertically upward is guided by the guide 45, and includes the transport belt 51 and the counter. It is sandwiched between the rollers 46 and conveyed, and the leading end is guided by the conveying guide 37 and pressed against the conveying belt 51 by the leading end pressing roller 49, and the conveying direction is changed by approximately 90 °.

  At this time, a positive output and a negative output are alternately repeated with respect to the charging roller 56, that is, an alternating voltage is applied, and a charging voltage pattern in which the conveying belt 51 alternates, that is, in a sub-scanning direction that is a circumferential direction. , Plus and minus are alternately charged in a band shape with a predetermined width. When the paper 42 is fed onto the conveyance belt 51 charged alternately with plus and minus, the paper 42 is attracted to the conveyance belt 51, and the paper 42 is conveyed in the sub-scanning direction by the circular movement of the conveyance belt 51.

  Therefore, by driving the recording head 34 according to the image signal while moving the carriage 33, ink droplets are ejected onto the stopped paper 42 to record one line, and after the paper 42 is conveyed by a predetermined amount, Record the next line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 42 has reached the recording area, the recording operation is finished and the paper 42 is discharged onto the paper discharge tray 3.

  When performing the maintenance and recovery of the nozzles of the recording head 34, the nozzle 33 performs the suction from the nozzles by moving the carriage 33 to a position facing the maintenance and recovery mechanism 81 which is the home position and performing capping by the cap member 82. By performing a maintenance and recovery operation such as idle ejection for ejecting droplets that do not contribute to image formation, image formation by stable droplet ejection can be performed.

Next, the maintenance / recovery mechanism 81 in this image forming apparatus will be described with reference to FIGS. 3 is a schematic schematic configuration diagram of the maintenance and recovery mechanism, FIG. 4 is an enlarged explanatory view of the main part, and FIG. 5 is an explanatory plan view of the same.
The maintenance / recovery mechanism 81 is capable of moving the caps 82a and 82b held by the cap holder 112, a wiper member 83 including an elastic body as a cleaning means, and a wiper cleaner 86 on the maintenance device frame 111 (up and down). Movable).

  A cylindrical empty discharge receiver 84 is disposed between the wiper member 83 and the suction cap 82a. The upper end of the empty discharge receiver 84 on the wiper member 83 side scrapes ink adhering to the wiper member 83. A wiper cleaner portion 85 to be dropped is formed. When cleaning the wiper member 83, the wiper member 83 is lowered while the wiper member 83 is pressed against the wiper cleaner portion 85 by the wiper cleaner 86, so that the ink adhering to the wiper member 83 is scraped off to the empty ejection receiver 84 side. .

  Here, the wiper cleaner 86 is rotatably attached to the upper end portion of the cleaner holder 182 for cleaning the ink attached to the wiper member 83 by wiping while contacting the wiper member 83. The cleaner holder 182 is swingably attached to the frame 111 by a support shaft 184, and is urged to swing to a retracted position side that does not contact the wiper member 83 by a tension spring (not shown). Further, a link member 188 is provided to swing the cleaner holder 182.

  Further, a scraping mechanism 190 for scraping off the ink transferred to the wiper cleaner unit 85 by cleaning the wiper member 83 is provided in the idle discharge receiver 84. The scraping mechanism 190 scrapes off the ink transferred to the wiper cleaner unit 85 by being swung by a scraping member 192 by a boss 191 provided on the roller 126 as a roller 126 described later rotates. Perform the action.

  Further, a tubing pump (suction pump) 120, which is a suction means, is connected to the cap 82a closest to the printing area via a flexible tube 119, and only the cap 82a is suctioned (recovered) and moisturized (hereinafter referred to as a cap). It is simply referred to as “suction cap”), and the cap 82b is simply a moisture retention cap. Therefore, when performing the recovery operation of the recording head 34, the recording head 34 that performs the recovery operation is selectively moved to a position where it can be capped by the suction cap 82a. The suction cap 82 is provided with an absorber 200.

  A cam shaft 121 rotatably supported by the frame 111 is disposed below the caps 82a and 82b, the wiper member 83, and the like. A cap cam 122 for moving the cap holder 112 up and down is disposed on the cam shaft 121. A wiper cam 124 for moving the wiper member 83 up and down, a roller 126 as a rotating body to which a droplet discharged in the idle discharge receptacle 84 is applied, a cleaner cam 128 for swinging the wiper cleaner 86, and a carriage lock Carriage lock cams 129 for raising and lowering 87 are provided.

  Here, the cap 82 is moved up and down by the cap cam 122. The wiper member 83 is moved up and down by the wiper cam 124, and the wiper cleaner 86 advances when the wiper member 124 is lowered. The ink adhering to 83 is scraped off into the empty discharge receiver 84.

  In order to rotationally drive the tubing pump 120 and the camshaft 121, the motor gear 132 provided on the motor shaft 131a rotates with the motor 131 and the pump gear 133 provided on the pump shaft 120a of the tubing pump 120 is meshed. An intermediate gear 136 with a one-way clutch 137 is engaged with an intermediate gear 134 integral with 133 via an intermediate gear 135, and the intermediate gear 138 coaxial with the intermediate gear 136 is fixed to the camshaft 121 via the intermediate gear 139. The cam gear 140 is engaged. An intermediate shaft 141 that is a rotation shaft of the intermediate gears 136 and 138 with the clutch 137 is rotatably held by the frame 111.

Next, an outline of the control unit of the image forming apparatus will be described with reference to FIG. This figure is an overall block diagram of the control unit.
This control unit controls the entire image forming apparatus, and includes a main control unit 301 configured by a microcomputer also serving as a means for performing a wiping operation according to the present invention, and a print control configured by a microcomputer that controls print control. Part 302.

  Then, the main control unit 301 includes a main scanning motor 331 and a conveyance roller 52 that move the carriage 33 in the main scanning direction in order to form an image on the paper 42 based on the printing processing information input from the communication circuit 300. The sub-scanning motor 332 that is driven to rotate is driven and controlled via the main scanning motor driving circuit 303 and the sub-scanning motor 304, and control such as sending print data to the print control unit 302 is performed.

  The main control unit 301 receives a detection signal from a carriage position detection circuit 305 that detects the position of the carriage 33, and the main control unit 301 controls the movement position and movement speed of the carriage 33 based on the detection signal. To do. The carriage position detection circuit 305 detects the position and speed of the carriage 33 by, for example, reading and counting the number of slits of an encoder sheet arranged in the scanning direction of the carriage 33 with a photosensor mounted on the carriage 33. The main scanning motor drive circuit 303 rotates the main scanning motor 331 according to the carriage movement amount and speed input from the main control unit 301 to move the carriage 33 to a predetermined position at a predetermined speed.

  Further, the main control unit 301 receives a detection signal from a conveyance amount detection circuit 306 that detects the movement amount of the conveyance belt 51, and the main control unit 301 moves the movement amount and movement speed of the conveyance belt 51 based on the detection signal. To control. The conveyance amount detection circuit 306 detects the conveyance amount and the conveyance speed by, for example, reading and counting the number of slits of the rotary encoder sheet attached to the rotation shaft of the conveyance roller 52 with a photo sensor. The sub-scanning motor driving circuit 304 rotates the sub-scanning motor 332 in accordance with the transport amount input from the main control unit 301, and rotationally drives the transport roller 52 to move the transport belt 51 to a predetermined position at a predetermined speed. Move with.

  The main control unit 301 rotates the sheet feeding roller 43 once by giving a sheet feeding roller driving command to the sheet feeding roller driving circuit 307. The main control unit 301 rotationally drives the motor 131 of the maintenance / recovery mechanism 81 via the maintenance / recovery mechanism drive motor drive circuit 308, thereby moving the cap 82 up and down, the wiper member 83 up and down, and driving the suction pump 120. Let it be done.

  The main control unit 301 drives and controls the ink supply motor for driving the pump of the supply unit via the ink supply motor drive circuit 311, and the ink cartridge 10 loaded in the cartridge loading unit 4 controls the head tank 35. Supply ink. At this time, the main controller 301 controls replenishment supply based on a detection signal from the head tank full sensor 312 that detects that the head tank 35 is full.

  Further, the main control unit 301 takes in information stored in the nonvolatile memory 316 which is a storage unit provided in each ink cartridge 10 mounted on the cartridge loading unit 4 through the cartridge communication circuit 314, and performs a necessary process. And stored in a non-volatile memory (for example, EEPROM) 315 which is a main body storage means.

  Further, the main control unit 301 receives a detection signal from an environmental sensor 313 that detects environmental temperature and environmental humidity.

  The print control unit 302 generates pressure for discharging droplets of the recording head 31 based on the signal from the main control unit 301 and the carriage position and conveyance amount from the carriage position detection circuit 305 and the conveyance amount detection circuit 306. Data for driving the means is generated, and the above-mentioned image data is transferred to the head drive circuit 310 as serial data, and the transfer clock and latch signal necessary for transferring the image data and confirming the transfer, drop control, etc. In addition to outputting a signal (mask signal) etc. to the head drive circuit 310, it comprises a D / A converter, a voltage amplifier, a current amplifier, etc. for D / A converting the pattern data of the drive signal stored in the ROM. Drive waveform generation means and drive waveform selection means to be given to the head driver, one drive pulse (drive signal) or a plurality of drive parameters. Scan to generate a plurality including driving waveform drive signal group consisting of (a drive signal) output to the head drive circuit 310.

  The head drive circuit 310 selectively selects a drive signal constituting a drive waveform supplied from the print control unit 302 based on image data corresponding to one row of the print head 34 that is input serially. The recording head 34 is driven by applying it to a driving element (for example, a piezoelectric element) that generates energy for discharging the ink. At this time, by selecting a driving pulse (driving signal) of a driving signal group constituting a driving waveform, it is possible to eject droplets having different sizes and to sort dots having different sizes.

Next, selection control of the maintenance / recovery operation by the maintenance / recovery mechanism 81 executed by the control unit in the image forming apparatus will be described with reference to FIG.
First, as the maintenance and recovery operation (cleaning operation) in this image forming apparatus, (1) automatic cleaning for charging mist automatically performed to remove the charging mist adhering to the nozzle surface of the recording head 34, and (2) recording. Automatic cleaning for paper dust automatically performed to remove paper dust and the like adhering to the nozzle surface of the head 34, (3) Manual cleaning performed when manual cleaning is instructed, (4) Liquid from the recording head 34 A cleaning operation after leaving automatically when the apparatus is left for a predetermined time (or period) without ejecting drops; (5) an ink filling operation for supplying ink to the head tank 35 in an open state; There is a cleaning operation included during the refreshing operation.

  Here, the process for selecting the maintenance / recovery operation mode described in FIG. 7 is targeted for the above-described automatic cleaning for charging mist (1) and automatic cleaning for paper dust (2). It is not performed during the cleaning operation. The automatic cleaning for charging mist (1) prevents discharge failure due to the nozzle surface adhering to the charging mist. When the mist count calculated by the following calculation formula exceeds a predetermined threshold, the cleaning operation is performed. It is an execution thing.

Mist count (nl) = mist coefficient × Σ (Mi value × number of drops) × 0.001
The mist coefficient in the equation is a coefficient set according to the use environment, print mode, ink used, and the like. The Mi value is a drop amount. (0.001) is a coefficient for converting (picoliter pl) to (nanoliter nl) as a unit.

Accordingly, when the above-described cleaning operation is entered, the wiping operation is selected (determined) according to the number of printed sheets per predetermined time, and the execution of the process of FIG. 7 is started.
First, it is determined whether or not the operation is an initial operation. If the operation is an initial operation, the maintenance and recovery operation mode 1 is executed as it is. It is determined whether or not the number is equal to or greater than (number of sheets + determination number of sheets). At this time, if the current total number of printed sheets is not equal to or greater than (total number of printed sheets at the time of previous determination + determined number of sheets), the previous mode is used.

  If the current total number of prints is equal to or greater than (total number of prints at the time of previous determination + determination number), the current average number of prints is calculated as (current total number of prints−total number of prints at the time of previous determination) / (current (The time at the previous determination−the time at the previous determination) is calculated. Then, the total number of printed sheets at the previous determination is changed (updated) to the current total number of printed sheets, and the time at the previous determination is changed to the current time. That is, here, the number of printed sheets per predetermined time is the number of printed sheets in the elapsed time from when the previous wiping operation was performed to immediately before the current wiping operation. As for the method for calculating the number of printed sheets per predetermined time, the number of printed sheets can be stored a plurality of times and the average value (average number of sheets) can be used.

  Thereafter, it is determined whether or not the current average number of printed sheets is equal to or greater than a predetermined average number of printed sheets threshold. At this time, if the current average number of printed sheets is not equal to or greater than the average number of printed sheets threshold, the maintenance recovery operation mode 1 is performed. If the current average number of printed sheets is equal to or greater than the average number of printed sheets threshold, the maintenance recovery operation mode 2 is performed. Perform maintenance and recovery.

Next, the operation of the maintenance / recovery operation mode 1 in this process will be described with reference to FIG.
First, the nozzle surface of the recording head 34 is raised and capped by the cap 82a, and the suction pump 120 is driven to suck and discharge ink from the nozzles of the recording head 34 (nozzle suction), and the cap 82a is lowered to wipe the wiper member. After the 83 is raised to the wiping height position, the carriage 33 is moved relative to the wiper member 83 to wipe the nozzle surface of the recording head 34 by the first wiping operation, and then the wiper member 83 is lowered. Then, the cap 82 is raised and the nozzle surface of the recording head 34 is capped.

The operation in the maintenance / recovery operation mode 2 will be described with reference to FIG.
First, the nozzle surface of the recording head 34 is raised and capped by the cap 82a, and the suction pump 120 is driven to suck and discharge ink from the nozzles of the recording head 34 (nozzle suction), and the cap 82a is lowered to wipe the wiper member. 83 is moved up to the wiping height position, then the carriage 33 is moved relative to the wiper member 83 to wipe the nozzle surface of the recording head 34, and then the wiper member 83 is lowered. The cap 82 is raised to cap the nozzle surface of the recording head 34.

Here, the wiping operation in the maintenance / recovery operation mode 1 (referred to as “first wiping operation”) will be specifically described with reference to FIG.
First, referring to FIG. 10A, as described above, the wiper blade (wiper member) 83 is raised to a position where it can contact the nozzle surface 34n of the recording head 34, and the carriage 33 is moved. By moving the wiper blade 83 relative to the nozzle surface 34n of the recording head 34, the wiper blade 83 is indicated by an arrow from the one end side to the other end side of the nozzle surface 34n in the state shown in the phantom line. The nozzle surface 34n is wiped while being moved in the direction C. As a result, the ink adhering to the nozzle surface 34 n of the recording head 34 becomes the ink mass 500 wiped up by the wiper blade 83.

  The position indicated by the phantom line in FIG. 10A is shown as the position where the wiper blade 83 starts to contact the nozzle surface 34n, and does not necessarily indicate the initial state when the wiper blade 83 is raised. . Further, one end side of the nozzle surface 34n means a wiping start side, and the other end side means a wiping end side. In addition, the “nozzle surface” means that the head including a nozzle cover that covers the peripheral portion of the nozzle surface includes the surface of the nozzle cover.

  At this time, the wiper blade 83 is stopped at a position indicated by a solid line that does not exceed the wiping end (the other end of the nozzle surface 34n) 34ne in the wiping direction (arrow C direction) of the recording head 34. Therefore, in this wiping step, the wiper blade 83 stops at the position where the nozzle surface 34n of the recording head 34 is not wiped off as the wiping end position.

  Then, as shown in FIG. 10B, when the wiper blade 83 is lowered in the direction indicated by the arrow D from the position where wiping is not completed (wiping end position), and the wiper blade 83 is separated from the nozzle surface 34n, the wipe is collected. Most of the obtained ink mass 500 becomes an ink mass 502 attached to the wiper blade 83 and is removed from the nozzle surface 34n. Then, since the wiper blade 83 is lowered in the direction of arrow D from the position where it is not wiped away and separated from the nozzle surface 31a, the tip 83A of the wiper blade 83 which has been deformed in the shape of “No” is gradually “I”. It will leave | separate from the nozzle surface 34a after becoming a character shape.

  As a result, the rapid restoring deformation of the tip 83A of the wiper blade 83 is suppressed, so that the ink mass 502 attached to the tip 83A due to wiping is reduced or eliminated.

  That is, when the wiper blade 83 is moved to a position beyond the wiping end 31ne in the wiping direction (arrow C direction) of the recording head 34, the tip 83A that has been deformed in the “No” shape becomes “No”. In the shape of a letter, it leaves the nozzle surface 34n and suddenly returns to the letter “I”, and the ink mass 502 adhering to the tip 83A scatters when the tip 83A is restored and deformed. Therefore, ink scattering is reduced by not wiping the nozzle surface to the end.

When the first wiping operation is performed in which the nozzle surface is not wiped off, ink may accumulate on the end surface (side surface) of the recording head 34 on the blow end side. This point will be described with reference to FIG. 11 in which the nozzle surface wiping end side surface 34e is enlarged.
As described above, when the wiper blade 83 is lowered in the direction indicated by the arrow D from the position where the nozzle surface 34n is not completely wiped away from the nozzle surface 34a, most of the ink mass 500 wiped and collected adheres to the wiper blade 83. The ink mass 502 which is removed from the nozzle surface 34n as a mass 502 and then adhered to the wiper blade 83 is scraped off by the wiper cleaner 86, and the wiper blade 83 is cleaned.

  However, it is confirmed that a part of the ink mass 500 wiped by the wiper blade 83 wraps around the wiping end side surface 34e of the recording head 34 and is attached as an ink mass 501a as shown in FIG. It was done. As a result, when the same maintenance / recovery operation is repeated, the lump 501a that wraps around the wiping end side surface 31e of the recording head 34 gradually accumulates and grows to become the ink lump 501b as shown in FIG. .

  There was no problem in performing the next maintenance / recovery operation with the ink mass 501b dried and fixed, but the next maintenance / recovery operation was repeatedly performed before the ink mass 501b was dried and fixed. Only in this case, the adhered ink mass 501b may become an ink mass 501c that hangs downward as shown in FIG. 11C due to vibration generated by the printing operation of the carriage 33 in the main scanning direction. Was confirmed.

  Since the ink lump 501c that hangs downward is at a position outside the operating area of the wiper blade 83, it is not removed even if the wiping process of the wiper blade 83 is performed, and gradually drops downward. Become. If the deposit (ink lump 501c) hangs downward, it eventually comes into contact with the paper surface (medium on which the liquid droplets are ejected), and the paper surface may be soiled.

  Therefore, a wiping operation (second wiping operation) for wiping up to the end face of the nozzle surface based on the number of printed sheets per predetermined time is performed.

Therefore, the wiping operation in the maintenance / recovery operation mode 2 (referred to as “second wiping operation”) will be specifically described with reference to FIG.
First, referring to FIG. 12A, as described above, the wiper blade (wiper member) 83 is raised to a position where it can contact the nozzle surface 34n of the recording head 34, and the carriage 33 is moved. By moving the wiper blade 83 relative to the nozzle surface 34n of the recording head 34, the wiper blade 83 is indicated by an arrow from the one end side to the other end side of the nozzle surface 34n in the state shown in the phantom line. The nozzle surface 34n is wiped while being moved in the direction C. As a result, the ink adhering to the nozzle surface 34 n of the recording head 34 becomes the ink mass 500 wiped up by the wiper blade 83.

  As in the case of the first wiping operation described above, the position indicated by the phantom line in FIG. 12A is shown as the position where the wiper blade 83 starts to contact the nozzle surface 34n, and the wiper blade 83 is not necessarily raised. It does not indicate the initial state when it is used. Further, one end side of the nozzle surface 34n means a wiping start side, and the other end side means a wiping end side. In addition, the “nozzle surface” means that the head including a nozzle cover that covers the peripheral portion of the nozzle surface includes the surface of the nozzle cover.

  After that, as shown in FIG. 12B, the wiper blade 83 is moved to a position beyond the nozzle surface wiping end 34ne in the wiping direction (arrow C direction) of the recording head 34 to completely wipe the nozzle surface 34n. .

  At this time, even when the ink lump 501c hangs down below the nozzle surface wiping end side surface 34e, the wiper blade 83 moves beyond the nozzle surface wiping end end 34ne. Is wiped off by.

  Therefore, it is possible to prevent the deposit (ink lump 501c) from dropping downward and coming into contact with the paper surface (medium on which droplets are ejected), thereby contaminating the paper surface.

  Here, in the second wiping operation, since the nozzle surface is wiped off, as described above, the attached ink may be scattered due to the restoring deformation of the wiper blade 83. Therefore, here, the wiper blade 83 is intermittently moved immediately before the wiper blade 83 wipes the nozzle surface 34n.

This operation will be described with reference to FIGS.
First, as described above, the wiper blade 83 is raised to a position where the wiper blade 83 can come into contact with the nozzle surface 34a of the recording head 34, and is moved relative to the nozzle surface 31n of the recording head 34, as shown in FIG. As shown in a), the wiper blade 83 wipes the nozzle surface 34a while moving in the arrow direction C.

  At this time, from the start of wiping shown in FIG. 13 to the point 34A in the region 31nb exceeding the nozzle region 34na, the wiping is performed by moving the wiper blade 83 at a constant speed, as shown in FIG. Thereafter, in a section from the point 34A to the position beyond the nozzle surface wiping end 34ne, wiping is performed while repeating a minute movement for a predetermined number of times to wipe it off. For example, an operation of intermittently moving a 0.3 mm width minutely 8 times is performed.

  By this operation, the tip of the wiper member is gradually released from the end of the nozzle surface (wiping end 34ne) at the time of wiping off, so that it is not rapidly restored and the scattering of ink lump adhering to the wiper member is reduced. In addition, it is possible to wipe off the high-viscosity deposit generated on the wiping end side surface of the head even if it drops downward.

  In this embodiment, as described above, the first wiping operation and the second wiping operation are selected based on the number of printed sheets for a predetermined time, and the elapsed time from when the previous wiping operation is performed to immediately before the current wiping operation is performed. When the number of printed sheets in (when calculated by the average number of printed sheets as described above) exceeds a predetermined number (threshold), the second wiping operation is performed to wipe off the nozzle surface. As for the method for calculating the number of printed sheets per predetermined time, the number of printed sheets may be stored a plurality of times and the average value (average number of sheets) may be calculated.

  This is because when the relationship between the number of printed sheets per day (printing speed) in this image forming apparatus and the total number of printed sheets when an ink adhesion phenomenon occurs is experimentally determined, an expected generation curve as shown in FIG. 15 is obtained. It is because it was obtained. That is, as described above with reference to FIG. 11, even when the ink mass 501b adheres to the side surface of the head when the wiping operation (first wiping operation) that is not wiped off is performed, the ink mass 501b is dried and fixed. If the next maintenance / recovery operation is performed in this state, the ink mass 501c does not sag, but only when the next maintenance / recovery operation is repeatedly performed before the ink mass 501b is dried and fixed. A sagging phenomenon such as 501c occurs.

  Therefore, if the number of printed sheets per predetermined time is small, the ink mass adhering to the side surface of the head is relatively dried and solidified. However, if the number of printed sheets per predetermined time is large, the maintenance and recovery operation is performed before drying and solidifying. It will be in a relationship. Therefore, the second wiping operation is performed based on (accordingly) the number of printed sheets per predetermined time.

  From this, for example, the elapsed time from the time of the previous maintenance and recovery operation is measured, and when the elapsed time is shorter than the set time, the second wiping operation is performed or the maintenance and recovery operation per predetermined time is performed. The second wiping operation may be performed under a predetermined condition such as counting the number of times and performing the second wiping operation when the number of maintenance and recovery operations per predetermined time exceeds the set number of times. it can.

  As described above, based on the number of prints per predetermined time, the first wiping operation in which the nozzle surface of the recording head is not wiped from the one end side to the other end side with the wiper member, and the nozzle surface of the recording head is wiped with the wiper member. Since the second wiping operation for wiping from one end side to the other end side is selected according to the number of prints per predetermined time, the deposit deposited by the first wiping operation hangs down without being completely dried. It can be removed by the second wiping operation before coming, and the paper surface can be prevented from being soiled by deposits.

  In addition, the wiper member performs a first wiping operation in which the nozzle surface of the recording head is not wiped from one end side to the other end side, and instead of the first wiping operation under a predetermined condition, a wiper member Since the second wiping operation for wiping the nozzle surface of the recording head from one end side to the other end side is performed, the second wiping operation is performed before the deposit accumulated by the first wiping operation hangs down without being completely dried. It can be removed and the paper surface can be prevented from being soiled by deposits.

Next, another embodiment of the present invention will be described with reference to FIG.
In this embodiment, as shown in FIG. 16A, after the wiper blade 83 is raised to a position where it can come into contact with the wiping end side surface 34e of the recording head 34, the wiper blade 83 is moved in the direction indicated by the arrow E (the first direction). As shown in FIG. 16B, the ink mass 501b attached to the wiping end side surface 34e of the recording head 34 is wiped by the wiper blade 83 by moving in the direction opposite to the wiping direction C of the wiping operation. The operation of lowering the wiper blade 83 is performed. In addition, although this operation | movement does not aim at wiping off a nozzle surface correctly, in this invention, it calls a "3rd wiping operation | movement" (or "back wiping operation | movement").

  Even by performing such a third wiping operation, the deposit (ink lump 501c in FIG. 11) hangs downward and comes into contact with the paper surface (medium on which droplets are ejected), which may contaminate the paper surface. Is prevented. However, in this third wiping operation, the wiper member needs to be raised relatively higher than the first wiping operation, and the configuration of the maintenance / recovery mechanism needs to be changed from that in the above embodiment. Further, since the third wiping operation does not wipe the nozzle surface 34n of the recording head 34, the third wiping operation is performed after the first wiping operation only when the number of printed sheets per predetermined time is equal to or greater than the threshold value. It is preferable to make it.

  In this way, the wiper member performs the first wiping operation in which the nozzle surface of the recording head is not wiped from one end side to the other end side, and the wiper member performs the first wiping operation based on the number of prints per predetermined time. By performing the third wiping operation for wiping the other end of the nozzle surface from the opposite direction to the first wiping operation, the third wiping operation is performed before the deposit accumulated by the first wiping operation hangs down without being completely dried. And can prevent the paper surface from being soiled by deposits.

  The image forming apparatus according to the present invention can be applied to a facsimile machine, a copying machine, a printer / fax / copier multifunction machine, etc., in addition to an inkjet printer. Furthermore, the present invention can also be applied to an image forming apparatus that discharges a liquid (recording liquid) other than ink, such as a resist or a DNA sample in the medical field.

1 is a schematic side view illustrating an overall configuration of a mechanism unit of an image forming apparatus according to the present invention. It is principal part plane explanatory drawing of the mechanism part. It is a typical schematic block diagram of the maintenance recovery mechanism in the same apparatus. It is a principal part expansion explanatory drawing similarly. It is a plane explanatory drawing similarly. It is a schematic block explanatory drawing explaining the control part of the apparatus. It is a flowchart with which it uses for description of the determination selection process of the maintenance recovery mode which the same control part performs. It is a flowchart with which it uses for description of the maintenance recovery mode 1 of FIG. It is a flowchart with which it uses for description of the maintenance recovery mode 1 of FIG. It is explanatory drawing with which it uses for description of a 1st wiping operation | movement. It is explanatory drawing with which it uses for description of generation | occurrence | production of the malfunction at the time of implementing only 1st wiping operation | movement. It is explanatory drawing with which it uses for description of a 2nd wiping operation | movement. It is explanatory drawing with which it uses for description of the operation speed of the wiper member in a 2nd wiping operation | movement. It is explanatory drawing with which it uses for description of the operating speed of a wiper member similarly. It is explanatory drawing which shows an example of the relationship between the total number of printed sheets of a day, and the total number of printed sheets when ink adhesion generate | occur | produces. It is explanatory drawing with which it uses for description of a 3rd wiping operation | movement.

Explanation of symbols

33 ... Carriage 34, 34a, 34b ... Recording head (liquid ejection head)
35 ... Head tank (liquid container)
81 ... Maintenance and recovery mechanism 82a, 82b ... Cap 83 ... Wiper member 84 ... Empty discharge receptacle 85 ... Wiper cleaner section 86 ... Wiper cleaner 121 ... Cam shaft 124 ... Wiper cam 128 ... Cleaner cam 131 ... Motor 141 ... Intermediate shaft

Claims (5)

A recording head having nozzles for discharging droplets;
A cap member for capping the nozzle surface of the recording head, a maintenance and recovery mechanism in which a wiper member for wiping the nozzle surface of the recording head is disposed;
Before Symbol a first wiping operation without Kira wiping to the other end side from the one end side of the nozzle face of the recording head in the wiper member, to the other end side of the nozzle surface from the one end of the recording head by the wiper member and a control means for controlling to I rows and a second wiping operation as possible wiping, a,
The control means performs control to perform the first wiping operation when the number of printed sheets per predetermined time is equal to or less than a preset threshold value, and to perform the second wiping operation when exceeding the threshold value,
The image forming apparatus according to claim 1, wherein the number of printed sheets per predetermined time is a number of printed sheets in an elapsed time from when the previous wiping operation is performed to immediately before the current wiping operation is performed . A recording head having nozzles for discharging droplets;
A cap member for capping the nozzle surface of the recording head, a maintenance and recovery mechanism in which a wiper member for wiping the nozzle surface of the recording head is disposed;
Before Symbol a first wiping operation without Kira wiping to the other end side from the one end side of the nozzle face of the recording head in the wiper member, to the other end side of the nozzle surface from the one end of the recording head by the wiper member and a control means for controlling to I rows and a second wiping operation as possible wiping, a,
The control means performs control to perform the first wiping operation when the number of printed sheets per predetermined time is equal to or less than a preset threshold value, and to perform the second wiping operation when exceeding the threshold value,
The image forming apparatus according to claim 1, wherein the number of printed sheets per predetermined time is an average of a plurality of printed sheets during an elapsed time from when the previous wiping operation is performed to immediately before the current wiping operation is performed. . 3. The image forming apparatus according to claim 1, wherein in the second wiping operation, the wiper member is intermittently applied to the carriage a predetermined number of times immediately before the wiper member wipes the other end portion of the nozzle surface. An image forming apparatus characterized in that the relative movement is performed. A recording head having nozzles for discharging droplets;
A cap member for capping the nozzle surface of the recording head, a maintenance and recovery mechanism in which a wiper member for wiping the nozzle surface of the recording head is disposed;
A first wiping operation without Kira wiping to the other end side from the one end side of the nozzle face of the recording head by the wiper member, the to payment wipe the other end side surface of the recording head in front Symbol wiper member Control means for performing control to perform three wiping operations ,
The control means is configured to perform the first wiping operation when the number of printed sheets per predetermined time is equal to or less than a preset threshold value, and to perform the third wiping operation subsequent to the first wiping operation when the threshold value is exceeded. And
The number of printed sheets per predetermined time is the number of printed sheets in the elapsed time from the previous wiping operation to immediately before the current wiping operation.
An image forming apparatus. A recording head having nozzles for discharging droplets;
A cap member for capping the nozzle surface of the recording head, a maintenance and recovery mechanism in which a wiper member for wiping the nozzle surface of the recording head is disposed;
A first wiping operation in which the wiper member does not wipe the nozzle surface of the recording head from one end side to the other end side; and a third wiping operation in which the wiper member wipes the side surface of the recording head on the other end side. Control means for performing control to perform
The control means is configured to perform the first wiping operation when the number of printed sheets per predetermined time is equal to or less than a preset threshold value, and to perform the third wiping operation subsequent to the first wiping operation when the threshold value is exceeded. And
The image forming apparatus according to claim 1, wherein the number of printed sheets per predetermined time is an average of a plurality of printed sheets during an elapsed time from when the previous wiping operation is performed to immediately before the current wiping operation is performed. .

Images