Image forming apparatus

An image forming apparatus includes a head part having a jet opening part configured to jet ink, a moisture retention cap configured to maintain moisture by covering the jet opening part, and a suction part configured to suction ink situated at the jet opening part. A suction cap having the suction part is provided separately from the moisture retention cap. The image forming apparatus includes a shutter member configured to open or close an opening part of the suction cap. The shutter member comes in contact with a perimeter of an edge part forming the opening part of the suction cap in a case where the shutter member is closed.

BACKGROUND

1. Technical Field

The present disclosure generally relates to image forming apparatuses, and more specifically an image forming apparatus including a head part having a jet opening configured to jet ink, a moisture retention cap configured to maintain moisture by closing the jet opening part, and a suction part configured to suction ink situated at the jet opening part.

2. Description of the Related Art

An inkjet printer as an image forming apparatus which jets an ink drop from a jet opening part of a head part so as to form an image on a recording medium is well known. A water type ink composed of a pigment and a solvent wherein a wetting agent (humectant) and penetrating agent are included in water, is used as ink liquid for such an inkjet printer. In an inkjet printer using the ink liquid, ink viscosity is increased due to evaporation of the ink solvent at a head jet opening so that the jet opening is clogged up or closed due to the adhesion of dust and thereby an image is degraded. In order to solve such a problem, Japan Laid-Open Patent Application Publications No. 2002-361905, No. 2003-1839, and No. 2003-1832 suggest a structure where a cap member for capping a head at the time of non-image forming so that moisture of a head jet opening is maintained and a suction mechanism such as a suction pump, provided at the cap member, for suctioning dust adhered to the jet opening together with the ink are provided. Thus, it is possible to prevent the increase of ink velocity.

By capping the head jet opening, ink viscosity is prevented from being increased due to the evaporation of the ink solvent at the head jet opening so that the jet opening is prevented from being clogged up. In addition, the dust adhered to the jet opening is suctioned together with the ink by the suction pump, so that the jet opening is prevented from being closed.

However, in the above-mentioned related arts disclosures, the ink suctioned by the suction pump is adhered to an internal wall surface of the cap member. Thus, if the head is capped in a state where the ink is adhered to the internal wall surface, the viscosity at the head jet opening is increased while the head jet opening is capped by the cap member. This causes an evaporation component such as water of the ink drop adhered to the internal wall surface of the cap member to evaporate when the cap member is opened, so that the ink drop, wherein the evaporation component adhered to the internal wall surface of the cap member evaporates, absorbs the evaporation component situated at the ink jet opening. As a result of this, the viscosity at the head jet opening is increased. Particularly, in a case where the ink liquid has a high viscosity, the image is influenced even if the viscosity at the head jet opening is slightly increased. Because of this, preliminary jetting is performed in order to adjust the viscosity of the jet opening and ink meniscus before printing starts. However, in order to adjust the viscosity of the jet opening, it is necessary to jet a lot of ink drops. Because of this, a lot of, from ten and several to several thousands, ink drops are jetted from a single jet opening for every preliminary jetting prior to start of the printing. This causes an increase in consumption of the ink.

The assignee of the present application suggests a structure where a moisture retention cap for maintaining moisture of the head jet opening and a suction cap for suctioning ink at the head jet opening are provided so that the viscosity of the ink is prevented from being increased at the time of moisture retention at the jet opening.

In a case where the moisture retention cap and the suction cap are separately provided, the suction cap is in a state where the suction cap is opened other than when the suction cap is suctioning the ink situated at the head jet opening. Because of this, a foreign body such as the dust enters into the suction cap and the dust is pulled into the suction tube and thereby it may not be possible to obtain a sufficient suction force due to closure of the flow path. In order to solve such a problem, a structure where a shutter member for covering an opening part of the suction cap at the time of non-operation of the suction means is provided is suggested at Japanese Patent Application No. 2004-184500. However, in the structure where the opening part of the suction cap is merely covered with the shutter member, a foreign body such as dust may enter into the suction cap via a gap between the opening part of the suction cap and the shutter member. Because of this, the dust may be pulled into the suction tube so that the flow path is closed and therefore sufficient suction force may not be obtained.

SUMMARY

The present disclosure provides an image forming apparatus whereby a foreign body such as dust can be prevented from coming into a suction cap so that a sufficient suction force is maintained for a long period of time.

The present disclosure provides an image forming apparatus, including:

a head part having a jet opening part configured to jet ink;

a moisture retention cap configured to maintain moisture by covering the jet opening part; and

a suction part configured to suction ink situated at the jet opening part;

wherein a suction cap having the suction part is provided separately from the moisture retention cap;

the image forming apparatus includes a shutter member configured to open or close an opening part of the suction cap; and

the shutter member comes in contact with a perimeter of an edge part forming the opening part of the suction cap in a case where the shutter member is closed.

The present disclosure provides an image forming apparatus, including:

a head part having a jet opening part configured to jet ink;

a moisture retention cap configured to maintain moisture by covering the jet opening part; and

a suction part configured to suction ink situated at the jet opening part;

wherein a suction cap having the suction part is provided separately from the moisture retention cap;

the image forming apparatus includes shutter means for opening or closing an opening part of the suction cap; and

the shutter means comes in contact with a perimeter of an edge part forming the opening part of the suction cap in a case where the shutter means is closed.

According to the above-mentioned gradation reproducing method, the suction cap configured to maintain the jet opening is provided separately from the moisture retention cap having the suction part configured to suction the ink situated at the jet opening part. Under this structure, ink is prevented from being adhered on an internal wall surface of the moisture retention cap and therefore viscosity of the ink is prevented from being increased at the time of maintaining moisture at the jet opening. The shutter member is provided so as to come in contact with the perimeter of the edge part forming the opening part of the suction cap in a case where the shutter member is closed. Under this structure, a foreign body such as dust is prevented from entering the suction cap and the dust is prevented from being pulled into a suction tube and thereby it is possible to avoid having an insufficient suction force due to closure of the flow path. As a result of this, a sufficient suction force can be maintained for a long period of time.

Other features and advantages will become more apparent from the following detailed description when read in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A description of examples and exemplary embodiments of the present invention is now given, with reference toFIG. 1throughFIG. 11. An inkjet printer (hereinafter “printer”) is discussed as an exemplary embodiment.

First, a basic structure of the printer is discussed.FIG. 1is a front view showing an example of a structure of the inkjet printer.

A printer100includes a printing mechanism23having a carriage9movably held in a main scanning direction crossing a conveying direction of a paper by a driving part. The printer100includes a conveying part21conveying a paper situated in a paper feeding tray18to the paper discharge tray26via a position facing the printing mechanism23.

Head13having plural jet openings for jetting ink liquid having colors of C (cyan), B (black), M (magenta), and Y (yellow) to the paper are provided in the carriage9of the printing mechanism23.

The conveying part21includes the paper feeding tray18, a paper feeding roller19, a separation pad20and a paper feeding guide27. A lot of papers are provided in the paper feeding tray18. The paper situated in the paper feeding tray18is sent to the conveying roller10by the paper feeding roller19. Only a single piece of paper among plural papers in the paper feeding tray18is sent to the conveying roller10by the separation pad20. The paper fed from the paper feeding tray18is guided by the paper feeding guide27. A conveying belt12is strained by the conveying roller10and a tension roller11. The conveying roller12conveys the conveyed paper to a position facing the head13. The conveying roller10is rotated clockwise by a driving part not shown inFIG. 1so that the conveying belt12moves endlessly in a direction shown by an arrow A inFIG. 1. The conveying part21has a pressing roller16pressing the paper to the conveying roller10, a guide22and a guide roller28which guide the paper, and a charging roller15for charging a surface the conveying belt12. The guide22converts the direction of the paper conveyed upward in a substantially vertical direction, at approximately 90 degrees along a curvature of the conveying roller10. Since the pressing roller16pushed the conveying belt12to the conveying roller10, friction between the conveying belt12and the conveying roller10is increased. Because of this, the conveying belt12is prevented from sliding against the conveying roller10so that the paper can be conveyed with high precision. A conveying guide14guiding the conveying belt12is provided at the side of the internal circumferential surface of the conveying belt12opposing the head13face. The conveying part21has a separation claw17separating the paper where the image is recorded from the conveying belt12, a paper discharge roller25discharging the paper to the paper discharging tray26and a spur24having a cross-section of a star-shaped configuration. The printer of this embodiment has a reverse mechanism30reversing a paper so that both surfaces of the paper can be printed.

FIG.2-(a) is a front view of the carriage9and FIG.2-(b) is a bottom view of the carriage9. As shown in FIG.2-(a), five heads13C,13Bk-1,13Bk-2,13M and13Y (hereinafter “C”, “Bk-1”, “Bk-2”, “M” and “Y”) are provided in the carriage9. As shown in FIG.2-(b), 2 lines each of 192 pieces of the jet opening13aare provided in the heads13.

FIG. 3is a plan view showing a structure of the inkjet printer. As shown inFIG. 3, a guide rod31supporting the carriage9pierces the carriage9and is provided between main body side surfaces100aand100b. Furthermore, a carriage support member (not shown inFIG. 3) is provided so as to extend in parallel with the main guide rod41having a certain gap therebetween. The carriage9is supported by the main guide rod41and the carriage support member so as to move in parallel with in a main scanning line direction. The carriage9includes sub-tanks32C,32Bk-1,32Bk-2,32M, and32Y (hereinafter “C”, “Bk-1”, “Bk-2”, “M” and “Y”) for supplying the ink liquid of respective colors to the heads13C,13Bk-1,13Bk-2,13M and13Y. First ends of ink drop supplying tubes33C,33Bk-1,33Bk-2,33M and33Y (hereinafter “C”, “Bk-1”, “Bk-2”, “M” and “Y”) corresponding to respective colors are connected to the respective sub-tanks32C,32Bk-1,32Bk-2,32M, and32Y. The other ends of the ink drop supplying tubes33are connected to a supplying pump35aof a cartridge filling part35where ink cartridges34C,34Bk-1,34Bk-2,34M, and34Y (hereinafter “C”, “Bk-1”, “Bk-2”, “M” and “Y”) situated at a upper side inFIG. 3. The ink cartridges34are detachably installed to the cartridge filling part35. The supplying pump35ais properly driven so that the ink liquid in the ink cartridge34is supplied to the sub-tank32via the supplying tube33. A harness47connecting a control part (not shown inFIG. 3) of the printer is provided in the carriage9.

A recovering and retaining apparatus40, having moisture retention caps41C,41Bk-1,41Bk-2,41M and41Y (hereinafter “C”, “Bk-1”, “Bk-2”, “M” and “Y”) corresponding to respective the color heads13C,13Bk-1,13Bk-2,13M and13Y and the suction cap42, is provided at the upper side inFIG. 3, namely an end side in a main scanning direction of the conveying belt12. The recovering and retaining apparatus40includes a first primary jet receiving part43, a wiper blade44and a roller45. The moisture retention cap41caps the jet opening13aof the head13at the time of non-image forming so that the jet opening13ais kept moist. In addition, a minute piercing hole connecting to the atmosphere is provided in the moisture retention cap41so that the moisture retention room is always kept at atmospheric pressure so that a meniscus of the jet opening13ais kept constant. The suction cap42is provided at a side (a lower side inFIG. 3) closer to the printing area than the moisture retention cap41. A suction hole42ais provided in the suction cap42. A suction part described below is provided at the suction hole42a. The suction part of the suction cap42suctions air bubbles or dust adhered to the jet opening13atogether with the ink so that bad jetting can be avoided. The first primary jet receiving part43is provided, for example, so as to perform primary jetting prior to the start of recording, arrange the meniscus of the jet opening13a, and keep a stable jet property. The wiper blade44cleans the ink liquid adhered to a surface having the jet opening13aof the head13. The roller45pushes the wiper blade44to the opening part of the first primary jet receiving part43so that a stain on the wiper blade44is removed by the opening part of the first primary jet receiving part43. Respective moisture retention cap41, the suction cap42, the wiper blade44, and the roller45can be moved upward and downward by a cam shaft described below. The details of the recovering and retaining apparatus40are discussed below.

Second primary jet receiving parts46C,46Bk-1,46Bk-2,46M, and46Y corresponding to the respective color heads13are provided at a lower side inFIG. 3of the conveying belt12. The second primary jet receiving part46causes ink whose color is not used for image forming during the process of image forming to have the same viscosity as the ink whose color is used. More specifically, the ink whose color is not used for image forming during the process of image forming is jetted to the second primary jet receiving part46so that the same viscosity of the ink whose color is used can be maintained.

Next, a printing operation of the printer of this embodiment is discussed. A signal of image information is set from a personal computer so that a printing process is implemented. First, the paper is fed from the paper feeding tray18to the conveying roller10by the paper feeding roller19. The paper fed from the paper feeding tray18is guided by the guide member22and the pressing roller16so as to be conveyed in a substantially vertical direction by the conveying belt12. The surface of the conveying belt12is charged by the charging roller15. The paper is attracted to and electrostatically adhered to the conveying belt12. The paper adhered to the conveying belt12is guided by the guide22and the press roller so that the direction of the paper is changed by approximately 90 degrees so as to be conveyed in a horizontal state to a position facing the head13. When the paper conveyed by the conveying belt12arrives at a position facing the head13, the conveying belt12is stopped so that the movement of the paper is stopped. The carriage9is positioned on the recovering and retaining apparatus40shown inFIG. 3prior to input of the image signal. This position is called a home position. Prior to the input of the image signal, the carriage9is positioned at the home position and the head13and the moisture retention cap41come in contact with each other, so that the jet opening13is in a state where the moisture is maintained. Based on the input of the image signal, the moisture retention cap41is lowered so that the carriage starts moving in a main scanning direction. Whenever the head13corresponding to the respective color is positioned in the first primary jet receiving part43, the carriage9is stopped moving so that several ink drops are jetted to the first primary jet receiving part43. After the primary jetting of the head13for each color is completed, moving of the carriage in a main scanning direction is restarted. Corresponding to the image signal, the carriage9is moved on the paper P in a main scanning direction. In addition, a designate ink liquid is jetted to a designated part of the paper P being stopped so that a single line of the image is formed on the paper P. A single line means a distance in a sub-scanning direction where the head13can record. After an image of a single line is formed, if necessary, the carriage9is moved to a position of the second primary jet receiving part46so that some ink drops of color not used in the image forming are jetted into the second primary jet receiving part46. After a single line in a main scanning direction is completed being recorded on the paper P, the conveying belt12is driven for a designated time so that the paper P is moved in a direction of the paper discharge tray26by a single line and then stopped. After the moving of the conveying belt12is stopped, corresponding to the image signal, the carriage moves on the paper P in a main scanning direction so that a single line of the image is formed.

Such a process is repeated a designated number of times so that a desirable image is printed on the paper P. Thus, when the image is formed on the paper by repeated conveying and stopping of the paper P, since the paper is electrostatically adhered to the conveying belt12, it is possible to stably convey the paper to a position facing the head13. In addition, since the paper is pushed to the conveying belt12by the pressing roller16, it is possible to securely electrostatically adhere the paper to the conveying belt12. The paper where the desirable image is printed is separated from the conveying belt12by the separation claw17, conveyed by the paper discharge roller25and the spur24, and discharged to the paper discharge tray26.

In a case where printing is performed for both surfaces of the paper, after a desirable image is printed on either surface of the paper, the rotation of the conveying belt12is reversed so that the paper is conveyed to the reversing mechanism30. The paper reversed by the reversing mechanism30is guided to the guide member22or the pressing roller26again and conveyed by the conveying belt12. After the paper arrives at a position facing the head part13, the same operation is performed so that the desirable image is printed on other surface of the paper. The paper having both surfaces where the desirable images are printed is separated from the conveying belt12by the separation claw17, conveyed by the paper discharge roller25and the spur24, and discharged to the paper discharge tray26.

After image forming is completed, the carriage9is moved again to the home position on the recovering and retaining apparatus40. The moisture retention cap41is raised so that the moisture at the jet opening13aof the head13is maintained.

The suction cap42is operated at the time of a cleaning mode. For example, a selection part such as a cleaning mode selection button is provided in the printer in advance. In a case where the user recognizes degradation of the image printed on the paper, the user selects the cleaning mode by the selection part so that the moisture retention cap41which maintains the moisture of the carriage9is lowered. The carriage9is moved so that the head13C is positioned on the suction cap42. After the head13C is positioned on the suction cap42, the carriage is stopped being moved. Then, the suction cap42is raised so as to come in contact with the head13, and thereby the air bubble or the dust adhered to the jet opening13atogether with the ink are suctioned by the suction part. After the suction operation is completed, the suction cap42is lowered. At the same time when the suction cap42is lowered, the wiper blade44is raised. After the wiper blade44is raised, the carriage9is moved so that the head13C slides against the wiper blade44. By moving the carriage9, the wiper blade44can remove an ink drop adhered due to sliding against the head13C of color, C. After removing the ink drop situated at the head13C, the wiper blade44is lowered. When the wiper blade44is lowered, the roller45is raised so that the wiper blade44is pushed to the opening part of the first primary jet receiving part43. Under this structure, as the wiper blade44is lowered, the ink drop adhered to the wiper blade44is removed by the opening part of the primary jet receiving part43so that the wiper blade44is cleaned. As the wiper blade44is lowered, the carriage9is moved so that head13C is positioned on the first primary jet receiving part43so that the primary jetting is performed by the first primary jet receiving part43.

The above-discussed operation is done for other color heads13Bk-1,13Bk-2,13M, and13Y so that the bad jetting of the heads13is avoided and the ink drops adhered to the heads13can be removed.

Thus, in this embodiment, since the moisture retention cap and the suction cap are separately provided, the ink drop is not adhered to the suction cap. Hence, the ink viscosity at the jet opening13ais prevented from increasing at the time of moisture retention. Because of this, it is not necessary to perform the primary jetting for arranging the ink viscosity at the primary jet prior to start of printing.

Although a case where the cleaning mode is selected by the user is discussed above, the cleaning mode may be implemented if the number of printing cycles a certain number, for example.

In addition, the suction operation is not limited to being performed at the time of the cleaning mode. For example, the suction operation may be implemented during an air opening filling mode.

Next, the recovering and retaining apparatus40is discussed. First, the moisture retention cap41of the recovering and retaining apparatus40is discussed.FIG. 4is a side schematic view of the recovering and retaining apparatus40. As shown inFIG. 4, the moisture retention cap41C capping the head13C for color C and the moisture retention cap41Bk-1capping the head13Bk-1for color Bk-1are held in the first holder50. The moisture retention cap41Bk-2capping the head13Bk-2for color Bk-2is held in the second holder51. The moisture retention cap41M capping the head13M for color M and the moisture retention cap41Y capping the head13Y for color Y are held in the third holder52. The first holder50is supported by the first slider60. More specifically, as shown inFIG. 4, a first projection50aand a second projection50brespectively provided at a side surface of a front side and a side surface of a deep side of the first holder50are respectively supported by a first concave part60aand a second concave part60brespectively provided at a side surface of a front side and a side surface of a deep side of the first slider60. Similarly, a first projection51aand a second projection51brespectively provided at a side surface of a front side and a side surface of a deep side of the second holder51are respectively supported by a first concave part61aand a second concave part61brespectively provided at a side surface of a front side and a side surface of a deep side of the second slider61. Similarly, a first projection52aand a second projection52brespectively provided at a side surface of a front side and a side surface of a deep side of the third holder52are respectively supported by a first concave part62aand a second concave part62brespectively provided at a side surface of a front side and a side surface of a deep side of the third slider62. The projections60care respectively provided at side surfaces of a front side and a deep side of the first slider60. As shown inFIG. 5, the projections60care inserted into first notch parts71aof the frame70of the recovering and retaining apparatus40. The projections61cprovided on the side surface of the second slider61are inserted into second notch parts71bof the frame70of the recovering and retaining apparatus40. The projections71cprovided on the side surfaces of the front side and the deep side of the third slider62are inserted into third notch parts71cof the frame70of the recovering and retaining apparatus40.

As shown inFIG. 4, a first cam80, a second cam81and a third cam82are respectively provided at the sliders60,61, and62. The cams80,81and82are fixed to a cam shaft84. The cam shaft84is connected to a driving part87via a first gear86aand a second gear86b.

FIG. 6is a schematic structural view of the first cam80. Since other cams have substantially same structures, explanation thereof is omitted. The first cam80includes a hole80aengaging with the cam shaft84and a cam groove80bprovided along a configuration of the cam80. A cam pin60dextending from the slider60is inserted into the cam groove80b. As the cam shaft84is rotated, the cam80fixed to the cam shaft84is rotated so that the cam pin60drelatively moves against the cam grove while the cam pin60dis supported by the cam groove80b. As a result of this, the first slider60is guided to the first notch part71ashown inFIG. 5so that the first slider60moves upward and downward. The moisture retention cap41C for a color C and the moisture retention cap41Bk-1for a color Bk-1, which are supported by the first slider60, move upward and downward.

The first cam80, the second cam81, and the third cam82are fixed to the cam shaft84while fixing angles are varied, so that the first cam80, the second cam81, and the third cam82move with time intervals and thereby torque can be decreased.

Next, the suction cap42of the recovering and retaining apparatus40is discussed. As shown inFIG. 4, the suction cap42is held by a suction cap holder53. A first projection53aand a second projection53bsituated at side surfaces of a front side and a deep side of the suction cap holder53are supported by a first concave part63aand a second concave part63bof the suction cap holder53. The suction cap42has a shutter54. In a state where the suction cap42is lowered as a normal operation, the shutter54is closed so that a foreign body such as dust may not enter into the suction cap42.

FIG. 7is a cross-sectional view of the suction cap42in a state where the shutter54is closed. As shown inFIG. 7, the suction cap42has a concave-shaped cross-section. A suction hole42ais provided at the bottom surface of the concave part42c. The shutter member54comes in contact with the edge part42bforming the opening part of the suction cap42.

As shown inFIG. 4, a shutter cam151is connected to a lower part of the shutter54. The shutter cam151is fixed to the cam shaft84while an angle is formed by the shutter cam151and the suction cap cam83.

Projections63care provided on side surfaces of the suction cap slider63. As shown inFIG. 5, the projection63cis supported by the suction cap notch part72. As shown inFIG. 4, a suction part90composed of the suction tube93and the suction pump91is provided in the suction cap42. The suction part90includes a waste tank92receiving the ink drop suctioned by the suction cap42.

The cam pin63dis provided at the suction cap slider63. The cam pin63dis inserted into a cam groove of the suction cap cam83. The suction cap cam83is fixed to the cam shaft84. The suction cap cam83has a substantially same structure as the first cam80, the second cam81, and the third cam82. The suction cap cam83is fixed to the cam shaft84while the fixing angle is different from the first cam80, the second cam81and the third cam82. A rotation area of the cam shaft84where only the moisture retention cap41moves upward and downward, a rotation area of the cam shaft84where only the suction cap42moves upward and downward, and a rotation area of the cam shaft84where the moisture retention cap41and the suction cap42move upward and downward, are calculated. Based on the result of the calculation, the fixing angle of the suction cap cam83is determined.

By controlling a driving time of the driving part87, only the moisture retention cap41moves upward and downward, only the suction cap42moves upward and downward, or the moisture retention cap41and the suction cap42move upward and downward.

FIG. 8is a perspective view showing the shutter54. The shutter54includes a shield part541having a cap contact surface541acoming in contact with the edge part42bof the suction cap42in a state where the suction cap42is lowered. Arm parts54cand54dare provided at deep and front sides of the shutter54. Projections54eand54fare provided at external side surfaces of the arm parts54cand54d. As shown inFIG. 5, the projections54eand54fare rotatably supported by long hole parts73provided at front and deep side surfaces of the frame70.

FIG.9-(a) is a view showing a state where the suction cap42is at a receiving position and FIG.9-(b) is a view showing a state where the suction cap42is at a suction position. As shown in FIG.9-(a), the suction cap slider63includes a removing member152configured to come in contact with the cap contact surface541aof the shield part541of the shutter54so as to remove the ink adhered to the cap contact surface541a. The primary jet receiving part43includes a pushing member43aconfigured to push the shield part541to a side of the suction cap42in a state where the edge part42bof the suction cap42comes in contact with the cap contact surface541aof the shield part541. The pushing part43acomes in contact with only the projection541bprojecting from the opening surface of the suction cap42in a state where the edge part42bof the suction cap42comes in contact with the cap contact surface541aof the shield part541. The head end of the pushing part43ais set to be a length so as to be not positioned on the opening part of the suction cap.

When the suction cap42is situated on the receiving position, the projection54eof the shutter member is positioned, as shown inFIG. 5, on the upper part of the long hole part73.

In a case where the suction operation is performed by the suction cap24, the cam shaft84is driven so that the suction cap42together with the suction cap slider63are moved downward. Furthermore, the shutter54is also moved downward so that the shield part541is separated from the pushing part43aof the primary jet receiving part43. After the shield part541is separated from the pushing part43a, as shown inFIG. 5, the shutter54and the suction cap slider63is moved downward until the projection54ecomes in contact with the lower part of the long hole part73. After the projection54ecomes in contact with the lower part of the long hole part73, the moving of the suction cap slider63is stopped. On the other hand, the shutter54is pulled downward by the shutter cam151. As a result of this, the shutter54is rotated counter-clockwise as shown by an arrow X in FIG.9-(a) regarding the projections54fand54eso that the suction cap42is opened. After the suction cap42is opened, the suction cap42is moved upward together with the suction cap slider63as shown in FIG.9-(b). At this time, the pushing part43ais not positioned on the opening surface of the suction cap42and therefore does not obstruct the upward moving of the suction cap42. During the upward moving of the suction cap42, the removing member152comes in contact with the cap contact surface541aof the shield part541. After the ink situated at the jet opening13aof the head13is suctioned, the cam shaft84is driven again so that the shutter54is pushed upward by the shutter cam151. At this time, the shutter54is rotated clockwise as shown by an arrow Y in FIG.9-(b) regarding the projections54fand54e. The cap contact surface541aof the shield part541slides and comes in contact with a removing member152so that the ink adhered to the contact surface541aof the shield part541is removed. In addition, the projection541bof the shield part541may come in contact with the side surface of the suction cap42while the ink situated at the contact surface541aof the shield part541being removed by the removing member152. In this case, the suction cap42is lowered together with the suction cap slider63to a position where the suction cap42does not come in contact with the end part541bof the shield part541. The length of the removing member152is arranged so that the removing member152does not come in contact with the contact surface541aof the shield part541even if the suction cap42is lowered to a position where the suction cap42does not come in contact with the edge part541bof the shield part541. Thus, after the ink situated at the contact surface541aof the shield part541is removed, the suction cap42is lowered together with the suction cap slider63. After the suction cap b42is lowered together with the suction cap slider63, the shutter54is rotated and the shield part541is positioned above the suction cap42. After that, the suction cap42is raised with the suction cap slider63so that the contact surface541aof the shield part541comes in contact with the periphery of the edge part42bforming the opening part of the suction cap42. In a state where the contact surface541acomes in contact with the edge part42b, the shutter54and the suction cap42are arisen with the suction cap slider63so that the shield part541is pushed to the pushing member43aas shown in FIG.9-(a). Thus, the contact surface541aof the shield part541can securely come in contact with the periphery of the edge part42bforming the opening part of the suction cap42.

In the above-discussed embodiment, the shutter54moves upward and downward in a state where the hole parts73supporting the projections54fand54eof the shutter54are used as long holes, so that the shield part541is pushed to the pushing part43a. However, the present invention is not limited to this. For example, the primary jet receiving part43may move upward and downward so that the pushing member43acomes in contact with the shield part541. In a case where suction operations are done by the suction cap42, first the primary jet receiving part43is moved upward so that the pushing part43ais separated from the shield part54. After the suction operation by the suction cap42and the removal of the ink situated at the shield part contact surface541aare completed, the shield part contact surface541aof the shutter54comes in contact with the edge part42bof the suction cap. After the contact surface541acomes in contact with the edge part42bof the suction cap42, the primary jet receiving part43is moved downward so that the pushing part43ais pushed to the shield part541and the contact surface541aof the shield part541comes in contact with the periphery of the edge part42bforming the opening part of the suction cap42.

Next, a modified example of the shutter54is discussed. The shutter54of this modified example is arranged in an area between the head and the suction cap and can be moved in parallel with the opening surface of the suction cap.

FIG. 10is a schematic plan view showing a shutter254of a modified example of the present invention.FIG. 11is a schematic cross-sectional view of the shutter254seen from a z direction ofFIG. 10. FIG.11-(a) shows a state where the shutter254is opened and FIG.11-(b) shows a state where the shutter254is closed.

As shown in FIG.11-(a), the length and width of the shutter254of the modified example is larger than the length and width of the suction cap. A rack254bis provided at one end of the cap contact surface254aof the shutter254. A gear255is engaged with the rack254band a driving part not shown inFIG. 11is provided at the gear255. A removing member256slides and comes in contact with the cap contact surface254aof the shutter254.

At the time of normal operations, namely when the suction cap42is not being used, as shown in FIG.11-(b), the contact surface254aof the shutter254comes in contact with the periphery of the edge part42bforming the opening part of the suction cap42so that the suction cap42is sealed. After the cleaning mode is implemented, the suction cap42is moved downward so that the suction cap42is separated from the shutter254. After that, a driving part not shown inFIG. 11is driven so that the gear255is rotated clockwise as shown by an arrow D inFIG. 11. As a result of this, the shutter254moves to a right side via the rack254bengaging with the gear255. At this time, the removing member256slides and comes in contact with the cap contact surface254aso that the ink situated at the cap contact surface254ais removed. After the shutter254moves to a position shown in FIG.11-(a), the carriage9is moved so that the head13C is situated on the suction cap42. After the head13C is situated on the suction cap42, the suction cap42is raised so as to come in contact with the head13. After the suction cap42comes in contact with the head13, the suction operation is started. After the suction operation is completed, the suction cap42is moved downward so as to be separated from the head13C. After the suction cap42is separated from the head13C, the carriage9is moved so that the head13Bk-1is situated on the suction cap42. After the head13Bk-1is situated on the suction cap42, the suction cap42is raised again so that the suction cap42comes in contact with the head13Bk-1and thereby the suction operation is started. After the suction operation is completed, the suction cap42is separated and the carriage9is moved so that next head13Bk-2is situated on the suction cap42. After the cleaning operation is performed for all of the heads13by repeating the above-discussed operation, the suction cap42is lowered to a position shown in FIG.11-(a). After that, the driving part is driven so that the gear255is rotated counter-clockwise as shown by an arrow D, and the shutter254is moved over the suction cap42. After the shutter254is moved over the suction cap42, the suction cap42is raised so that the cap contact surface254aof the shutter254comes in contact with the edge part42bof the suction cap42and thereby the suction cap42is sealed.

According to an image forming apparatus of the above-discussed embodiment of the present invention, the moisture retention cap41configured to maintain the moisture at the jet opening part and the suction cap42configured to suction the ink situated at the jet opening part are separately provided. Hence, the ink does not adhere to the internal wall surface of the moisture retention cap41. Therefore, the ink situated on the internal wall surface does not take the evaporation component of the ink situated at the jet opening part in so that the viscosity of the ink situated at the jet opening part is prevented from being increased. As a result of this, it is not necessary to perform a primary jetting for adjusting the viscosity of the jet opening part prior to start of printing and therefore the amount of ink consumed can be reduced. Furthermore, the shutter54is provided so as to come in contact with the edge part42bof the suction cap42in a case where the shutter member is closed. Because of this, a foreign body such as dust is prevented from entering the suction cap42. As a result of this, the dust is prevented from being pulled into the suction tube93and thereby it is possible to avoid having an insufficient suction force due to closing of the flow path. As a result of this, a sufficient suction force can be maintained for a long period of time.

If the cap contact surface of the shutter where the ink is adhered comes in contact with the edge part42bof the suction cap42, the ink adhered to the cap contact surface may be adhered to the edge part42bof the suction cap42. As a result of this, the ink adhered to the edge part42nof the suction cap may be adhered to the head13at the time when the opening surface of the suction cap42comes in contact with the head for suctioning operations, so that the head13may get dirty.

However, in this embodiment, a removing part configured to remove ink adhered to the suction can contact surface of the shutter is provided. Under this structure, the ink adhered to the cap contact surface can be prevented from being adhered to the edge part42bof the suction cap. Because of this, the head13can be prevented from getting dirty by contacting the edge part42bof the suction cap when the edge part42bof the suction cap comes in contact with the head13for suctioning operations.

Furthermore, in this embodiment, the removing member comes in contact with a cap contact surface of the shutter at the time of the operation of opening or closing of the shutter so that the ink adhered on the contact surface of the shutter member is removed. Under this structure, it is possible to securely remove the ink from the cap contact surface.

In addition, the suction cap42is opened or closed by rotating the shutter54. It may be difficult for the edge part42bof the suction cap42and the contact surface541aof the shutter54to be in parallel with each other on the suction cap42. That is, even when the shutter54is slightly sifted from a contact position where the shutter54comes in contact with the suction cap42, the suction cap42may not be in parallel with the cap contact surface541aof the shutter54. Furthermore, in a case where the suction cap42is raised so that the suction cap42comes in contact with the cap contact surface541aof the shutter54, the shutter54is pushed by the suction cap42and therefore the cap contact surface541aof the shutter54cannot be in parallel with the edge part42bof the suction cap42. Thus, the suction cap42may be closed by the shutter in a state where the cap contact surface541aof the shutter54is not parallel with the edge part42bof the suction cap42. As a result of this, a gap may be formed between the suction cap42and the cap contact surface541aand a foreign body such as dust may enter through the gap.

However, in the modified example, the shutter254moves in parallel with the edge part42bof the suction cap42so that the suction cap42is opened or closed. Therefore, even in a case where the cap contact surface254aof the shutter254coming contact with the suction cap42is opened by the suction cap42, it is possible to keep the cap contact surface254aand the edge part42bparallel to each other. Hence, the suction cap42is not be closed by the shutter254in a state where the cap contact surface254aof the shutter and the edge part42bof the suction cap42are in parallel each other. As a result of this, the cap contact surface254aof the shutter254securely comes in contact with a periphery of the edge part42bof the suction cap42. Hence, a gap is not formed between the edge part42bof the suction cap42and the cap contact surface254aof the shutter254and thereby it is possible to prevent a foreign body such as dust from entering.

Furthermore, if the shutter does not have rigidity, when the suction cap is raised so as to come in contact with the contact surface of the shutter, the shutter may be deformed. The suction cap may be closed by the shutter in a state where the cap contact surface of the shutter is not parallel to the edge part42bof the suction cap. As described above, when the suction cap42is raised so as to come in contact with the contact surface of the shutter54, the shutter54is pushed by the suction cap42, the shutter54is rotated, and it may be difficult for the edge part42bof the suction cap42and the contact surface541aof the shutter54to be in parallel with each other.

However, in this embodiment, the pushing member43ais provided so as to push the shutter to a side of the suction cap42in a state where the edge part42bof the suction cap42comes in contact with the shutter. Under this structure, it is possible to prevent the shutter from being deformed or rotated when the suction cap42is raised and comes in contact with the cap contact surface. Hence, the suction cap can be closed in a state where the cap contact surface of the shutter is in parallel with the edge part42bof the suction cap42. Because of this, the cap contact surface of the shutter can come in contact with the periphery of the edge part42bof the suction cap42. Hence, a gap is not formed between the edge part42bof the suction cap42and the cap contact surface254aof the shutter254and thereby it is possible to prevent a foreign body such as dust from entering.

Furthermore, in this embodiment, the pushing member is situated at a position where the pushing member does not obstruct moving of the suction cap when the suction cap moves. More specifically, in a state where the suction cap is closed by the shutter, the pushing member comes in contact with the projection part of the shutter projecting from the opening part of the suction cap so that the head end of the pushing member is not positioned at an upper part of the opening part of the suction cap. Thus, even if the shutter is opened at the time of suctioning and the suction cap moves upward, the pushing member does not come in contact with the suction cap and the pushing member does not obstruct upward movement of the suction cap.

The present invention is not limited to the above-discussed examples and exemplary embodiments, but variations and modifications may be made without departing from the scope of the present disclosure and the appended claims.

Although the inkjet printer is discussed as an example of the image forming apparatus of the present invention, the present invention is not limited to this. For example, the present invention can be applied to a copier, fax machine, or multiple function machine having a printer, fax machine and copier, having an image reading apparatus configured to read image information such as a scanner and forming an image on a recording paper based on an image read by the image reading apparatus.

This patent application is based on Japanese Priority Patent Application No. 2004-266417 filed on Sep. 14, 2004, the entire contents of which are hereby incorporated by reference.