Patent Description:
Conventionally, as an inkjet image forming apparatus with an ink containing a binder resin, has been known an apparatus that forms an image by flocculating an ink and a flocculant not containing a binder resin as a pretreatment liquid on the surface of a recording medium in order to prevent penetration of the ink into the recording medium. An ink head for such an image formation has an ink discharge face and an ink adheres thereto, so that the adhered ink is cleaned periodically (for example, see <CIT> and <CIT>).

An inkjet recording apparatus including a cleaning device with a cleaning blade is disclosed in <CIT>. The cleaning device makes the rigidity of the cleaning blade different for each of a plurality of recording heads to clean the plurality of recording heads.

A cleaning device that cleans a plurality of droplet discharge heads (recording heads) is disclosed in <CIT>. The cleaning device includes a cleaning roller and a cleaning blade for cleaning the plurality of droplet discharge heads. The cleaning device in <CIT> cleans each of the plurality of droplet discharge heads with a cleaning roller and the cleaning blade.

In order to enhance adhesion to a recording medium, such an image forming apparatuses as described in <CIT> and <CIT> typically uses an ink containing a binder resin high in adhesive force.

If the image forming apparatus in <CIT> uses an ink high in adhesive strength, it is difficult to remove the ink dried and fixed to a nozzle face. In this case, it is conceivable to increase the pressure of the cleaning blade brought into contact with the nozzle face, but the durability of the recording heads is lowered.

In addition, such a cleaning device with a cleaning roller and a cleaning blade as described in the <CIT> cleans a recording head less frequent in cleaning. As a result, excessive maintenance is performed, which increases the maintenance cost. <CIT> discloses an inkjet recording apparatus according to the preamble of claim <NUM> that includes: a liquid set which includes a plurality of first liquids and a second liquid, wherein the first liquids each contain solvent-insoluble materials, and wherein the second liquid causes the solvent-insoluble materials to form aggregate; a liquid ejection device which ejects the first liquids and the second liquid from different ejection ports; and a cleaning liquid supply device which supplies a cleaning liquid that causes the aggregate of the solvent-insoluble materials to redispersed. The liquid set satisfies Dmax/Drain<= <NUM>, where Dmax is a maximum of average particle sizes of the solvent-insoluble materials in the first liquids, and Dmin is a minimum of the average particle sizes of the solvent-insoluble materials in the first liquids.

<CIT> discloses an inkjet recording device that includes: a carriage that is mounted with a recording head that has an ink discharging part; a carriage drive motor which reciprocates the carriage in a prescribed scanning direction; a cleaning roller which is immersed into a prescribed liquid and in which a cleaning part for cleaning the ink discharging part of the recording head is formed at its outer peripheral surface; and a control part which performs control so that dew condensation generated at the ink discharging part of the recording head is cleaned while moving the carriage in a scanning direction every time the carriage is scanned prescribed times while discharging an ink to a recording medium from the recording head.

According to a first aspect, the present invention provides an image forming apparatus in accordance with independent claim <NUM>. According to a second aspect, the present invention provides an image forming method in accordance with claim <NUM>. Further aspects are set forth in the dependent claims, the drawings and the following description.

An object of the present invention is to provide an image forming apparatus and an image forming method that enable reduction in maintenance cost without excessive maintenance.

To achieve the abovementioned object, according to an aspect of the present invention, an image forming apparatus that discharges droplets, while moving a recording head relative to a recording medium in a main scanning direction and a sub-scanning direction, to form an image, reflecting one aspect of the present invention comprises: a carriage; a first recording head that has a first discharge face having a hole, that is disposed on the carriage, that discharges a first droplet containing resin through the hole, and that is included in the recording head; a second recording head that has a second discharge face having a hole, that is disposed on the carriage, that discharges, through the hole, a second droplet containing resin less than the resin contained in the first droplet, and that is included in the recording head; a first cleaning device that wipes the first discharge face to clean the first recording head; and a second cleaning device that is different from the first cleaning device and that wipes the second discharge face to clean the second recording head.

The advantages and features provided by one or more embodiments of the invention will become more fully understood from the detailed description given hereinbelow and the appended drawings which are given by way of illustration only, and thus are not intended as a definition of the limits of the present invention:.

Hereinafter, respective image forming apparatuses according to one or more embodiments of the present invention will be described with reference to the drawings.

<FIG> illustrates the configuration of an image forming apparatus <NUM> according to a first embodiment of the present invention. <FIG> is a plan view of the image forming apparatus <NUM>, and <FIG> is a side view thereof. <FIG> is a schematic sectional view of a first cleaning device.

As illustrated in <FIG>, the image forming apparatus <NUM> includes a recording head <NUM> including a plurality of recording heads and a cleaning device <NUM> including a plurality of cleaning devices. In the present embodiment, the image forming apparatus <NUM> is an inkjet image forming apparatus, and discharges droplets while moving the recording head <NUM> relative to a recording medium in the main scanning direction (first direction) D1 and the sub-scanning direction (second direction) D2. In the present embodiment, the main scanning direction D1 is a direction orthogonal to the sub-scanning direction D2.

The droplets form an image on the surface of the recording medium. Examples of the recording medium include recording media typically used for inkjet recording, such as paper, fabric, plastic films, and glass plates. The recording medium may be a sheet-shaped medium cut in a predetermined size, or may be a long medium that is wound like a roll and can be fed continuously.

The image forming apparatus <NUM> may form an image on a recording medium with the recording head <NUM> fixed or with the recording medium fixed. In the present embodiment, the recording medium intermittently movable in the sub-scanning direction D2 by a conveying device (not illustrated), and the recording head <NUM> is movable in the main scanning direction D1. In the present embodiment, the cleaning device <NUM> is movable at least in the sub-scanning direction D2.

The recording head <NUM> includes a first recording head <NUM> and a second recording head <NUM>. The first recording head <NUM> and the second recording head <NUM> are mounted on a first carriage <NUM> movable on a first rail <NUM> bridged in the width direction of the recording medium. The first recording head <NUM> and the second recording head <NUM> reciprocate in the main scanning direction D1 as the first carriage <NUM> reciprocates in the main scanning direction D1.

The first recording head <NUM> has a first discharge face 111a having a hole through which a first droplet is discharged. The first droplet is a so-called ink containing a resin. The number of first recording heads <NUM> is not particularly limited. The number of first recording heads <NUM> is appropriately set in response to the color type of the first droplet to be discharged. In the present embodiment, the number of first recording heads <NUM> is four. The first recording heads <NUM> each discharge the first droplet through the hole of the first discharge face 111a while moving in the main scanning direction D1, thereby recording a desired image onto the recording medium intermittently moved in the sub-scanning direction D2.

The second recording head <NUM> has a second discharge face 112a having a hole through which a second droplet is discharged. The second droplet contains less resin than the resin contained in the first droplet. The second droplet preferably contains no resin. In the present embodiment, the second droplet is a flocculant for aggregating the first droplet or an overcoat liquid. The number of second recording heads <NUM> is not particularly limited. In the present embodiment, the number of second recording heads <NUM> is one. The second recording head <NUM> discharges the second droplet through the hole of the second discharge face 112a to the recording medium while moving in the main scanning direction D1. Due to the discharge of the second droplet to the recording medium to which the first droplet has been discharged, the first droplet is aggregated by the second droplet to be fixed to the recording medium. The first droplet may be discharged immediately after the second droplet is discharged. In a case where a flocculant and an overcoat liquid are each discharged from the second recording head <NUM>, the number of second recording heads <NUM> is two. Alternatively, the overcoat liquid may be discharged from the first recording head <NUM> in response to the amount of resin contained in the overcoat liquid.

The array of the first recording heads <NUM> and the second recording head <NUM> on the first carriage <NUM> is not particularly limited. In the present embodiment, the recording head <NUM> includes the first recording head <NUM>, the first recording head <NUM>, the first recording head <NUM>, and the second recording head <NUM> disposed in this order in view along the main scanning direction D1.

The cleaning device <NUM> includes a first cleaning device <NUM> and a second cleaning device <NUM>. The cleaning device <NUM> may be movable in the main scanning direction D1, may be movable in the sub-scanning direction D2, or may be fixed. The first cleaning device <NUM> and the second cleaning device <NUM> may be movable individually or simultaneously. In the present embodiment, the first cleaning device <NUM> and the second cleaning device <NUM> are mounted on a second carriage <NUM> movable on a second rail <NUM> disposed along the sub-scanning direction D2. Namely, the first cleaning device <NUM> and the second cleaning device <NUM> may be movable simultaneously. The first cleaning device <NUM> and the second cleaning device <NUM> reciprocate in the sub-scanning direction D2 as the second carriage <NUM> reciprocates in the sub-scanning direction D2. In a case where the first cleaning device <NUM> and the second cleaning device <NUM> are movable individually, the first cleaning device <NUM> and the second cleaning device <NUM> are mounted on separate carriages (not illustrated).

The first cleaning device <NUM> wipes a first droplet having adhered to the first discharge face 111a of each first recording head <NUM>. The configuration of the first cleaning device <NUM> is not particularly limited as long as the above function can be exhibited. The first cleaning device <NUM> includes a first cleaning member 121a. As illustrated in <FIG>, the first cleaning device <NUM> in the present embodiment includes a container 121b with the cleaning liquid W stored therein and a squeeze member 121c in addition to the first cleaning member 121a. The first cleaning member 121a preferably has a surface layer formed of a moisture-absorbable elastic member, from the viewpoint of removing the first droplet. The first cleaning member 121a includes a wet roller (sponge) or as a not claimed embodiment a wet web (nonwoven fabric). From the viewpoint of wiping the first discharge face 111a to which the first droplet containing resin has been adhered, the first cleaning member 121a has thus a removing force (strong cleaning force) that increases depending on the rotational speed (the faster is stronger) and the rotational direction (the direction counter to the movement direction of the first cleaning device <NUM> is stronger).

One first cleaning device <NUM> may be disposed for one first recording head <NUM>, or one first cleaning device may be disposed for a plurality of first recording heads <NUM>. In the present embodiment, the first cleaning device <NUM> is disposed for the four first recording heads <NUM>. Namely, in the present embodiment, the first cleaning device <NUM> is provided so as to be able to collectively clean the four first recording heads <NUM>.

In the present embodiment, the first cleaning device <NUM> is movable in the sub-scanning direction D2. At the time of image formation, the first cleaning device <NUM> is disposed at a position different from a position corresponding to the first discharge faces 111a of the first recording heads <NUM>. At the time of no image formation, the first cleaning device <NUM> moves to the position corresponding to the first discharge faces 111a of the first recording heads <NUM> to clean the first recording heads <NUM>. <FIG> exemplarily illustrates the first cleaning device <NUM> disposed away from the first recording heads <NUM> in the conveyance direction (sub-scanning direction D2) of the recording medium.

The first cleaning device <NUM> is connected to a first waste-liquid container <NUM>. The first waste-liquid container <NUM> disposes the first waste liquid having been wiped by the first cleaning member 121a. The configuration of the first waste-liquid container <NUM> is not particularly limited as long as the above function can be exhibited. In the present embodiment, the first waste-liquid container <NUM> includes a first waste-liquid tank 125a, and a first connection passage 125b that connects the first cleaning device <NUM> and the first waste-liquid tank 125a.

The second cleaning device <NUM> wipes the second droplet having adhered to the second discharge face 112a of the second recording head <NUM>. The configuration of the second cleaning device <NUM> is not particularly limited as long as the above function can be exhibited. The second cleaning device <NUM> includes a second cleaning member 122a. The second cleaning member 122a includes a dry blade (rubber member) or as a not claimed embodiment a dry web. From the viewpoint of wiping the second discharge face 112a to which the second droplet containing no resin has been adhered, the second cleaning member 122a thus reduces the head load and eliminates excessive maintenance.

One second cleaning device <NUM> may be disposed for one second recording head <NUM>, or one second cleaning device may be disposed for a plurality of second recording heads <NUM>. In the present embodiment, the number of second recording heads <NUM> is one and the number of second cleaning devices <NUM> is one.

In the present embodiment, the second cleaning device <NUM> is movable in the sub-scanning direction D2. At the time of image formation, the second cleaning device <NUM> is disposed at a position (standby position) different from a position corresponding to the second discharge face 112a of the second recording head <NUM>. At the time of no image formation, the second cleaning device <NUM> moves to the position corresponding to the second discharge face 112a of the second recording head <NUM> to clean the second recording head <NUM>. <FIG> exemplarily illustrates the second cleaning device <NUM> disposed away from the second recording head <NUM> in the conveyance direction (sub-scanning direction D2) of the recording medium. The second cleaning device <NUM> may be movable in the height direction D3 orthogonal to the main scanning direction D1 and the sub-scanning direction D2. In the present embodiment, the second cleaning device <NUM> is movable in the sub-scanning direction D2 and the height direction D3.

The second cleaning device <NUM> is connected to a second waste-liquid container <NUM>. The second waste-liquid container <NUM> disposes the second waste liquid having been wiped by the second cleaning member 122a. The configuration of the second waste-liquid container <NUM> is not particularly limited as long as the above function can be exhibited. In the present embodiment, the second waste-liquid container <NUM> includes a second waste-liquid tank 126a and a second connection passage 126b that connects the second cleaning device <NUM> and the second waste-liquid tank 126a.

The cleaning force of the first cleaning device <NUM> to such a first recording head <NUM> as described above is preferably stronger than the cleaning force of the second cleaning device <NUM> to the second recording head <NUM>. As described above, the first cleaning device <NUM> wipes the first droplet containing the resin, and the second cleaning device <NUM> wipes the second droplet containing no resin. Thus, the recording head <NUM> is not excessively maintained, so that the discharge face of the recording head <NUM> is not excessively worn.

<FIG> is a block diagram illustrating the main functional configuration of the image forming apparatus <NUM>. The image forming apparatus <NUM> includes a controller <NUM>, a recording head driver <NUM>, an input/output interface <NUM>, a cleaning device driver <NUM>, and a detector <NUM>.

The controller <NUM> includes a central processing unit (CPU) 150a, a random access memory (RAM) 150b, a read only memory (ROM) 150c, and a storage 150d.

The CPU 150a reads various control programs and setting data stored in the ROM 150c, stores the programs and the setting data in the RAM 150b, and executes the programs to perform various types of arithmetic processing. Further, the CPU 150a centrally controls the entire operation of the image forming apparatus <NUM>.

The RAM 150b provides the CPU 150a with a working memory space and stores temporary data. The RAM 150b may include a non-volatile memory.

The ROM 150c stores, for example, the various control programs executed by the CPU 150a and the setting data. Instead of the ROM 150c, a rewritable non-volatile memory such as an electrically erasable programmable read only memory (EEPROM) or a flash memory may be used.

The storage 150d stores a print job (image recording command) input from an external device <NUM> through the input/output interface <NUM>, and image data related to the print job and cleaning data. As the storage 150d, for example, a hard disk drive (HDD) may be used, or a dynamic random access memory (DRAM) may be used in combination.

Under the control of the controller <NUM>, the recording head driver <NUM> supplies a drive signal corresponding to image data to such a first recording head <NUM> as described above and the second recording head <NUM> at suitable timing, thereby causing each nozzle of the first recording head <NUM> and the second recording head <NUM> to discharge the first droplet and the second droplet in an amount corresponding to the pixel value of the image data.

The input/output interface <NUM> mediates transmission and reception of data between the external device <NUM> and the controller <NUM>. The input/output interface <NUM> includes, for example, any of various serial interfaces and various parallel interfaces, or a combination thereof.

The external device <NUM> is, for example, a personal computer, and supplies an image recording command (print job), image data, and the like to the controller <NUM> through the input/output interface <NUM>.

Under the control of the controller <NUM>, the cleaning device driver <NUM> causes the first cleaning device <NUM> and the second cleaning device <NUM> to move, at suitable timing, according to the cleaning data stored in the storage 150d to clean the first recording heads <NUM> and the second recording head <NUM>.

The detector <NUM> detects the position of the first carriage <NUM> and detects the number of times of cleaning of the cleaning device <NUM>. The detector <NUM> includes, for example, various sensors.

Next, an image forming method and a cleaning operation with the image forming apparatus <NUM> will be described. <FIG> explanatorily illustrate the cleaning operation. <FIG> is a flowchart illustrates the cleaning operation.

Here, in the image forming apparatus <NUM>, the first carriage <NUM> (such first recording heads <NUM> as described above and the second recording head <NUM>) is movable in the main scanning direction D1, and a recording medium and the second carriage <NUM> (the first cleaning device <NUM> and the second cleaning device <NUM>) are movable in the sub-scanning direction D2.

The image forming method with the image forming apparatus <NUM> includes discharging droplets, with the first recording heads <NUM> and the second recording head <NUM> moving relative to the recording medium in the main scanning direction D1 and the sub-scanning direction D2, to form an image; wiping, by the first cleaning device <NUM>, the first discharge faces 111a to clean the first recording heads <NUM>; and wiping, by the second cleaning device <NUM>, the second discharge face 112a to clean the second recording head <NUM>.

In the image formation, while the first carriage <NUM> scans in the main scanning direction (forward operation), first droplets are discharged from the first recording heads <NUM> and second droplets are discharged from the second recording head <NUM> to form an image onto the recording medium. At this time, because the first droplets are discharged immediately after the second droplets are discharged, the first droplets are mixed with the second droplets and aggregated on the recording medium. After the recording medium is moved in the sub-scanning direction D2, while the first carriage <NUM> scans in the main scanning direction D1 (backward operation), first droplets are discharged from the first recording heads <NUM> and second droplets are discharged from the second recording head <NUM> to form an image on the recording medium. Then, the recording medium is moved in the sub-scanning direction D2. Repetition of this operation results in image formation with the first droplets and the second droplets on the recording medium.

The recording head <NUM> is cleaned before image formation is performed or when no image formation is performed after image formation.

As illustrated in <FIG> and <FIG>, the controller <NUM> causes the first carriage <NUM> to move a position where cleaning is to be performed (S110). As a result, the first recording heads <NUM> and the second recording head <NUM> move to a position where the cleaning is to be performed. Next, the controller <NUM> causes the detector <NUM> to acquire positional information of the first carriage <NUM> (S120).

Then, as illustrated in <FIG> and <FIG>, the controller <NUM> having detected that the first carriage <NUM> is disposed at the position where the cleaning is to be performed causes the second carriage <NUM> to move in the sub-scanning direction D2 (forward operation) (S130). As a result, the first cleaning member (wet roller) 121a of the first cleaning device <NUM> wipes the first discharge faces 111a of the first recording heads <NUM>, and the second cleaning member (dry blade) 122a of the second cleaning device <NUM> wipes the second discharge face 112a of the second recording head <NUM>. In the present embodiment, the timing at which the first cleaning device <NUM> wipes the first recording heads <NUM> is the same as the timing at which the second cleaning device <NUM> wipes the second recording head <NUM>. In such a manner, because the first recording heads <NUM> are wiped by the dedicated first cleaning device <NUM> and the second recording head <NUM> is wiped by the dedicated second cleaning device <NUM>, excessive maintenance is not performed.

Then, the controller <NUM> causes the second carriage <NUM> to move in the sub-scanning direction D2 (backward operation).

The second carriage <NUM> may reciprocate a plurality of times in the sub-scanning direction D2. As a result, even in a case where the first droplets having firmly adhered to the first discharge faces 111a, the first discharge faces 111a can be wiped.

The timing at which the first cleaning device <NUM> cleans the first recording heads <NUM> may be different from the timing at which the second cleaning device <NUM> cleans the second recording head <NUM>.

<FIG> and <FIG> are explanatory flowcharts each illustrating the timing at which the first cleaning device <NUM> cleans the first recording heads <NUM> is different from the timing at which the second cleaning device <NUM> cleans the second recording head <NUM>.

As illustrated in <FIG>, the controller <NUM> causes the first carriage <NUM> to move (S110), acquires positional information of the first carriage <NUM> having moved (S120), and then acquires information regarding a difference in the number of times of cleaning (S130). Then, the controller <NUM> detects whether or not the difference in the number of times of cleaning is <NUM> (S140). If the difference in the number of times of cleaning is <NUM>, the first recording heads <NUM> and the second recording head <NUM> are cleaned (S150). After the cleaning of the first recording heads <NUM> and the second recording head <NUM>, the information regarding the difference in the number of times of cleaning is deleted (S160). If the difference in number of times of cleaning is less than <NUM>, the first recording heads <NUM> are cleaned (S170). Specifically, when the controller <NUM> causes the second carriage <NUM> to move in the sub-scanning direction D2, the second cleaning device <NUM> is retracted in the height direction D3 so as not to come into contact with the second recording head <NUM>. In such a manner, the second cleaning device <NUM> moves in the height direction D3, so that the wiping timing can be adjusted even if the first cleaning device <NUM> and the second cleaning device <NUM> move simultaneously.

Alternatively, first cleaning-count information may be acquired to adjust the timing of cleaning. As illustrated in <FIG>, the controller <NUM> causes the first carriage <NUM> to move (S110), acquires positional information of the first carriage <NUM> having moved (S120), and then acquires the first cleaning-count information (S135). The first cleaning-count information is the number of times of cleaning of the first recording heads <NUM> performed by the first cleaning device <NUM>. Then, the controller <NUM> detects whether or not the first cleaning count is <NUM> (S145). If the first cleaning count is <NUM>, the first recording heads <NUM> and the second recording head <NUM> are cleaned (S150). After the cleaning of the first recording heads <NUM> and the second recording head <NUM>, the first cleaning-count information is deleted (S165). If the first cleaning count is less than <NUM>, the first recording heads <NUM> are cleaned (S170). Specifically, when the controller <NUM> causes the second carriage <NUM> to move in the sub-scanning direction D2, the second cleaning device <NUM> is retracted in the height direction D3 so as not to come into contact with the second recording head <NUM>. In such a manner, the second cleaning device <NUM> moves in the height direction D3, so that the wiping timing can be adjusted even if the first cleaning device <NUM> and the second cleaning device <NUM> move simultaneously.

The difference in the number of times of cleaning can be appropriately changed to an optimum difference according to, for example, the size of the image forming apparatus <NUM>, or the type of the first droplet and the second droplet. Here, whether to wipe the first recording heads <NUM> or to wipe both the first recording heads <NUM> and the second recording head <NUM> is set on the basis of the number of times of cleaning. However, the setting may not be set on the basis of the number of times of cleaning. For example, it may be set on the basis of the storage amounts of the first waste-liquid tank 125a and the second waste-liquid tank 126a. In this case, the first waste-liquid tank 125a and the second waste-liquid tank 126a each include a liquid-level detection sensor (not illustrated) that detects the liquid level. Further, each of the first cleaning device <NUM> and the second cleaning device <NUM> may be forcibly driven.

As described above, according to the image forming apparatus <NUM> of the present embodiment, the first recording heads <NUM> are cleaned by the first cleaning device <NUM> and the second recording head <NUM> is cleaned by the second cleaning device <NUM>, so that the maintenance cost can be reduced without excessive maintenance.

Next, an image forming apparatus <NUM> according to a second embodiment will be described. The image forming apparatus <NUM> of the present embodiment includes a recording head <NUM> on a first carriage <NUM>. The recording head <NUM> on the first carriage <NUM> is different in disposition from the recording head <NUM> on the first carriage <NUM> of the image forming apparatus <NUM> of the first embodiment. The components of the image forming apparatus <NUM> similar to those of the image forming apparatus <NUM> of the first embodiment are denoted with the same reference signs, and thus the description thereof will not be given.

<FIG> explanatorily illustrate a cleaning operation of the image forming apparatus <NUM> according to the second embodiment. <FIG> is a flowchart illustrating the cleaning operation of the image forming apparatus <NUM> according to the second embodiment. <FIG> illustrate the first carriage <NUM> and a second carriage <NUM>.

As illustrated in <FIG>, the image forming apparatus <NUM> in the present embodiment includes a first recording head <NUM>, a second recording head <NUM>, a first cleaning device <NUM>, and a second cleaning device <NUM>. The first recording head <NUM> and the second recording head <NUM> are mounted on the first carriage <NUM>. The first cleaning device <NUM> and the second cleaning device <NUM> are mounted on the second carriage <NUM>.

In the present embodiment, a plurality of first recording heads <NUM> and one second recording head <NUM> are arrayed in the main scanning direction D1, and a plurality of arrays (two arrays in the present embodiment) are disposed in the sub-scanning direction D2. The two recording-head arrays have a difference in position in the main scanning direction D1.

The first cleaning device <NUM> can clean three first recording heads <NUM>, and the second cleaning device <NUM> can clean one second recording head <NUM>. The first cleaning device <NUM> in the present embodiment cannot clean the entire of the recording head <NUM> in one cleaning operation (forward operation or backward operation).

As illustrated in <FIG> and <FIG>, a controller <NUM> causes the first carriage <NUM> to move to a position where cleaning is to be performed (S110), and acquires positional information of the first carriage <NUM> having moved (S120). Thereafter, the controller <NUM> causes the second carriage <NUM> to move in the sub-scanning direction D2 (forward operation: upward in the figure) (S130), and the first recording heads <NUM> and the second recording head <NUM> are cleaned.

As illustrated in <FIG> and <FIG>, the controller <NUM> causes the first carriage <NUM> to move in the main scanning direction D1 (S170). At this time, the controller <NUM> causes the first carriage <NUM> to move such that an uncleaned first recording head <NUM> is cleaned by the second cleaning device <NUM>.

As illustrated in <FIG> and <FIG>, the controller <NUM> causes the second carriage <NUM> to move in the sub-scanning direction D2 (backward operation: downward in the figure) (S180). At this time, because there is no second recording head <NUM> to be cleaned, the second cleaning device <NUM> is retracted in the height direction D3 so as not to come into contact with the first recording heads <NUM>. As a result, the first cleaning device <NUM> cleans the uncleaned first recording head <NUM>.

Then, the controller <NUM> determines whether cleaning has been repeated predetermined number of times (S190). If the entire of the recording head <NUM> is already cleaned, the cleaning operation ends (S190; Yes). If the entire of the recording head <NUM> is not yet cleaned, the controller <NUM> causes the first carriage <NUM> to move in the main scanning direction D1 (S200), and step S130 to step S190 are repeated.

In such a manner, according to the image forming apparatus <NUM> of the present embodiment, the movement of the first carriage <NUM> in the main scanning direction D1 (rightward in the figure) and the movement of the second carriage <NUM> in the sub-scanning direction D2 (upward and downward in the figure) are repeated, so that the entire of the recording head <NUM> can be cleaned.

After the cleaning of the entire of the recording head <NUM> is completed, the controller <NUM> causes the second cleaning device <NUM> to move to its original position.

As described above, the image forming apparatus <NUM> of the present embodiment has effects similar to those of the image forming apparatus <NUM> of the first embodiment.

Next, an image forming apparatus <NUM> according to a third embodiment will be described. The image forming apparatus <NUM> of the present embodiment includes a recording head <NUM> on a first carriage <NUM>. The recording head <NUM> on the first carriage <NUM> of the third embodiment are different in disposition from the recording head <NUM> on the first carriage <NUM> of the image forming apparatus <NUM> of the first embodiment. A cleaning device <NUM> on a second carriage <NUM> of the third embodiment is different in disposition from the cleaning device <NUM> on the second carriage <NUM> of the first embodiment. The components of the image forming apparatus <NUM> similar to those of the image forming apparatus <NUM> of the first embodiment are denoted with the same reference signs, and thus the description thereof will not be given.

<FIG> illustrates the configuration of the image forming apparatus <NUM> according to the third embodiment.

In the present embodiment, on the first carriage <NUM>, a plurality of (eight) first recording heads <NUM> and two second recording heads <NUM> are arrayed in the main scanning direction D1. More specifically, one of the two second recording heads <NUM> is disposed adjacent to the leftmost first recording head <NUM> of the plurality of (eight) first recording heads <NUM>, and the other one of the two second recording heads <NUM> is disposed adjacent to the rightmost first recording head <NUM> of the plurality of (eight) first recording heads <NUM>. That is, the plurality of (eight) first recording heads <NUM> is interposed between the two second recording heads <NUM>.

In the present embodiment, one first cleaning device <NUM> and two second cleaning devices <NUM> are mounted on the second carriage <NUM>. More specifically, one of the second cleaning devices <NUM> is disposed at one end of the first cleaning device <NUM> and the other one of the second cleaning devices <NUM> is disposed at the other end of the first cleaning device <NUM>. Namely, the one first cleaning device <NUM> is interposed between the two second cleaning devices <NUM>.

In this case, a controller <NUM> causes the first carriage <NUM> to move to a position where cleaning is to be performed (S110), and acquires positional information of the first carriage <NUM> having moved (S120). Thereafter, the controller <NUM> causes the second carriage <NUM> to move in the sub-scanning direction D2 (forward operation: upward in the figure) (S130), and the first recording heads <NUM> and the second recording heads <NUM> are cleaned.

Next, an image forming apparatus <NUM> according to a fourth embodiment will be described. The image forming apparatus <NUM> of the present embodiment includes a recording head <NUM> on a first carriage <NUM>. The recording head <NUM> on the first carriage <NUM> is different in disposition from the recording head <NUM> on the first carriage <NUM> of the image forming apparatus <NUM> of the first embodiment. The components of the image forming apparatus <NUM> similar to those of the image forming apparatus <NUM> of the first embodiment are denoted with the same reference signs, and thus the description thereof will not be given.

<FIG> explanatorily illustrates a cleaning operation of the image forming apparatus <NUM> of the fourth embodiment.

As illustrated in <FIG>, the image forming apparatus <NUM> in the present embodiment includes a first recording head <NUM>, a second recording head <NUM>, a first cleaning device <NUM>, and a second cleaning device <NUM>. The first recording head <NUM> and the second recording head <NUM> are mounted on the first carriage <NUM>, and the first cleaning device <NUM> and the second cleaning device <NUM> are fixed.

In the present embodiment, on the first carriage <NUM>, a plurality of (four) first recording heads <NUM> and one second recording head <NUM> are arrayed in the main scanning direction D1. The first carriage <NUM> is preferably movable to the outside of an area for image formation on a recording medium by the recording head <NUM>.

In the present embodiment, the first cleaning device <NUM> is disposed at one end outside the recording medium in the main scanning direction D1, and the second cleaning device <NUM> is disposed at the other end outside the recording medium in the main scanning direction D1. The first cleaning device <NUM> and the second cleaning device <NUM> are preferably disposed outside the area for image formation on the recording medium by the recording head <NUM>. With this arrangement, cleaning is performed outside the area for image formation. Thus, the area for image formation is not contaminated in the case of a cleaning failure. The first cleaning device <NUM> can clean all the first recording heads <NUM> by one movement, and the number of second cleaning devices <NUM> is one.

In this case, a controller <NUM> causes the first carriage <NUM> to move in the main scanning direction D1 (leftward in the figure) to clean the first recording heads <NUM> by the first cleaning device <NUM>, and causes the first carriage <NUM> to move in the main scanning direction D1 (rightward in the figure) to clean the second recording head <NUM> by the second cleaning device <NUM>.

As described above, the image forming apparatus <NUM> of the present embodiment has effects similar to those of the image forming apparatus <NUM> of the first embodiment. In the image forming apparatus <NUM> of the present embodiment, the first cleaning device <NUM> and the second cleaning device <NUM> are fixed. Thus, the manufacturing cost can be reduced as compared with the image forming apparatus <NUM> of the first embodiment.

<FIG> explanatory illustrates a cleaning operation of an image forming apparatus <NUM> of a fifth embodiment.

As illustrated in <FIG>, the image forming apparatus <NUM> in the present embodiment includes a first recording head <NUM>, a second recording head <NUM>, a first cleaning device <NUM>, and a second cleaning device <NUM>. The first recording head <NUM> and the second recording head <NUM> are mounted on a first carriage <NUM>, and the first cleaning device <NUM> and the second cleaning device <NUM> are fixed.

In the present embodiment, on the first carriage <NUM>, a plurality of (eight) first recording heads <NUM> and two second recording heads <NUM> are arrayed in the main scanning direction D1. The first carriage <NUM> is preferably movable to the outside of an area for image formation on a recording medium by the recording head <NUM>.

In the present embodiment, the first cleaning device <NUM> is disposed at one end outside the recording medium in the main scanning direction D1, and the second cleaning device <NUM> is disposed at the other end outside the recording medium in the main scanning direction D1. The first cleaning device <NUM> is movable in the height direction D3. The first cleaning device <NUM> and the second cleaning device <NUM> are preferably disposed outside the area for image formation on the recording medium by the recording head <NUM>. With this arrangement, cleaning is performed outside the area for image formation. Thus, the area for image formation is not contaminated in the case of a cleaning failure.

In this case, a controller <NUM> causes the first carriage <NUM> to move in the main scanning direction D1 (rightward in the figure). At this time, the first cleaning device <NUM> remains retracted so as not to come into contact with the second recording heads <NUM> in the height direction D3. After the second recording head <NUM> passes, the first cleaning device <NUM> moves to a position where the first cleaning device <NUM> comes into contact with the second recording head <NUM>. Then, the first cleaning device <NUM> cleans the first recording heads <NUM>, and the second cleaning device <NUM> cleans the second recording heads <NUM>.

Further, the controller <NUM> causes the first carriage <NUM> to move in the main scanning direction D1 (leftward in the drawing). Then, the first cleaning device <NUM> cleans the first recording heads <NUM>, and the second cleaning device <NUM> cleans the second recording heads <NUM>.

As described above, the image forming apparatus <NUM> of the present embodiment has effects similar to those of the image forming apparatus <NUM> of the first embodiment. In the image forming apparatus <NUM> of the present embodiment, the first cleaning device <NUM> is movable in the height direction D3 and the second cleaning device <NUM> is fixed. Thus, the manufacturing cost can be reduced as compared with the image forming apparatus <NUM> of the first embodiment.

The image forming apparatuses and the image forming methods according to the above embodiments enable reduction in maintenance cost without excessive maintenance. Therefore, according to the above embodiments, it is expected to spread an image forming apparatus and an image forming method that have low maintenance cost and good image quality of an image to be formed.

According to embodiments of the present invention, provided can be an image forming apparatus and an image forming method that enable maintaining long-duration cleaning performance.

Claim 1:
An image forming apparatus (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) configured to discharge droplets, while moving a recording head (<NUM>) relative to a recording medium in a main scanning direction (D1) and a sub-scanning direction (D2), to form an image, the image forming apparatus (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) comprising:
a carriage (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>);
a first recording head (<NUM>) that has a first discharge face (111a) having a hole, that is disposed on the carriage (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), that is configured to discharge a first droplet containing resin through the hole, and that is included in the recording head (<NUM>);
a second recording head (<NUM>) that has a second discharge face (112a) having a hole, that is disposed on the carriage (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), that is configured to discharge, through the hole, a second droplet containing less resin than the resin contained in the first droplet, and that is included in the recording head (<NUM>);
a first cleaning device (<NUM>) configured to wipe the first discharge face (111a) to clean the first recording head (<NUM>); and
a second cleaning device (<NUM>) that is different from the first cleaning device (<NUM>) and that is configured to wipe the second discharge face (112a) to clean the second recording head (<NUM>);
characterized in that
the first cleaning device (<NUM>) includes a wet roller, and the second cleaning device (<NUM>) includes a dry blade.