JP3864421B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus that preliminarily ejects ink onto a conveyance belt to perform nozzle cleaning of a recording head.

In an inkjet image forming apparatus, an image is formed on a recording sheet by ejecting ink from the recording head onto the recording sheet while the recording sheet is conveyed by a conveying belt. In such an image forming apparatus, in order to prevent drying and cleaning of the nozzles of the recording head that are always in contact with the outside air, ink is preliminarily ejected from the nozzles to the ink receiver at every predetermined time (purge, idle ejection, spit). However, there is a drawback that an ink receiving portion is required separately. In order to solve this problem, a technique is known in which an ink receiving portion is provided on the conveying belt, and when the ink receiving portion of the conveying belt faces downward, the ink in the ink receiving portion is naturally dropped and removed ( Patent Document 1).
JP-A-9-109377

  However, in such an image forming apparatus, when the amount of pre-discharged ink is very small (for example, about several pl), the solvent component of the ink rapidly vaporizes and the ink is fixed on the transport belt, and the ink is easily removed. There was a fault that could not be (natural fall).

  Further, in Patent Document 1, since the ink receiver is formed at a specific portion of the transport belt, there is a problem that the preliminary discharge cannot be performed at an arbitrary position on the belt and the productivity of image formation is lowered.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an image forming apparatus capable of reliably removing ink on a conveyor belt and improving productivity.

For the present invention, to attain the aforementioned object, comprising: a conveyance belt that conveys a recording medium, and a plurality of recording heads for forming an image by ejecting droplets against the recording medium on the conveyance belt In the image forming apparatus, the entire surface of the conveyance belt that conveys the recording medium is subjected to liquid repellent treatment , and the belt surface of the conveyance belt is wound around each recording head by winding the conveyance belt. formed curvature of the corresponding concave, the the curved portion is characterized in that guide rollers for guiding the droplets aggregated into the curved portion is disposed.

  According to the present invention, it is possible to aggregate liquid droplets on the curved portion of the transport belt. In addition, since the guide roller for guiding the droplets is disposed in the curved portion, the droplets aggregated in the curved portion can be removed by the rotation of the guide roller accompanying the driving of the conveying belt. In particular, if a spiral groove that guides the ink to the guide roller is formed, the ink in the spiral groove is pushed out by the spiral groove as the guide roller rotates, so that the droplet in the spiral groove follows the guide roller. The droplets can be removed from the belt surface of the conveyor belt.

  Moreover, in order to achieve the said objective, this specification discloses the following invention (1)-(3).

  The invention (1) is an image forming apparatus comprising: a conveying belt that conveys a recording medium; and an image forming unit that forms an image by ejecting droplets from the recording head onto the recording medium. The surface is subjected to a liquid repellent treatment for repelling droplets adhering to the belt surface, and droplets are landed from the recording head to substantially the same droplet hitting place on the belt surface during the recovery operation of the recording head. It has a droplet discharge control means.

  According to the invention (1), on the belt surface of the transport belt subjected to the liquid-repellent treatment, droplets are landed from the recording head to substantially the same droplet deposition site on the belt surface during the recovery operation (preliminary ejection) of the recording head. Since the droplet discharge control means is provided, the droplets can be repeatedly landed and the droplets can be coalesced and aggregated on the belt surface. As a result, large droplets that are coalesced and aggregated can be naturally dropped at the belt turning position, and the recoverability of the droplets can be improved. Further, since droplets can be landed at an arbitrary position on the belt surface, it is not necessary to determine the position of the recording paper with respect to the conveying belt, and the productivity of the recording paper can be improved. In particular, in a full-line type head in which a plurality of recording heads for each ink color are arranged, ink can be removed efficiently if ink landing from the recording heads of each color is repeatedly landed at substantially the same droplet deposition location. The

  The invention (2) is an image forming apparatus comprising: a conveying belt that conveys a recording medium; and an image forming unit that forms an image by ejecting droplets from the recording head onto the recording medium. A concave portion for collecting droplets is formed on the surface, and a liquid repellent treatment is performed to repel liquid droplets adhering to the belt surface. During the recovery operation of the recording head, the droplets are combined in the concave portion. It is characterized by aggregation.

  According to the invention (2), since droplets can be collected in the recess for collecting droplets formed on the belt surface of the conveyor belt, the coalescence aggregation of the droplets can be promoted, and the droplet collecting effect can be improved. . Examples of the shape of the recess include a dimple shape and a groove shape in order to efficiently combine and aggregate the pre-discharged droplets.

  Invention (3) is an image forming apparatus comprising: a conveying belt that conveys a recording medium; and an image forming unit that forms an image by ejecting droplets from the recording head onto the recording medium. It is characterized by being inclined by 1 to 10 degrees with respect to a horizontal plane in a direction perpendicular to the medium conveyance direction.

  According to the invention (3), since the conveyance belt is inclined by 1 to 10 degrees with respect to the horizontal plane in the direction perpendicular to the conveyance direction of the recording medium, the liquid droplets that have landed on the belt surface can flow down from the belt surface and be removed. .

  In this specification, “recording” represents the concept of forming an image in a broad sense including characters. A “recording medium” is a medium (called an image forming medium, a recording medium, an image receiving medium, a recording paper, or the like) that receives printing by a recording head, such as continuous paper, cut paper, sticker paper, OHP sheet, etc. Regardless of the resin sheet, film, cloth, and other materials and shapes, various media are included.

  According to the present invention, it is possible to reliably remove droplets on the conveyor belt and improve productivity.

  Hereinafter, a first embodiment of an image forming apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is an overall configuration diagram of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus 10 includes a plurality of recording heads 12 (12K, 12C, 12M, 12Y) provided for each ink color, that is, black (K), cyan (C), magenta (M), and yellow (Y). A belt conveyance unit 18 that is arranged to face the recording head 12 and conveys the recording paper 16 by a belt 38 while maintaining the flatness of the recording paper 16; a paper feeding unit 20 that supplies the recording paper 16; A paper discharge unit 22 for discharging the recording paper on which the image has been recorded from the inside of the apparatus to the outside of the apparatus.

  The recording head 12 is a so-called full-line head in which line-type heads having a length corresponding to the paper width of the recording paper 16 are arranged in a direction orthogonal to the paper feed direction.

  Roll paper (continuous paper) 26 is detachably set in the paper supply unit 20. Although the roll paper 26 is used as an example of the paper supply unit 20, a plurality of roll papers having different paper widths, paper quality, and the like may be provided together with the roll paper 26. Further, instead of or in combination with the roll paper 26, the cut paper may be supplied by a cassette 26A in which cut papers are stacked and loaded. Reference numeral 27 denotes a supply roller that conveys and supplies cut paper from the cassette 26A.

  In the vicinity of the paper feeding unit 20, drawer rollers 21 and 21 for pulling out the recording paper 16 from the roll paper 26 are provided. The power of the motor 109 (see FIG. 3) is transmitted to at least one of the drawing rollers 21 and 21, and the drawn recording paper 16 is conveyed from right to left in FIG. Here, reference numeral 24 is a cutter for cutting disposed between the rollers 21 and 21, and the recording paper 16 drawn from the roll paper 26 by this cutter 24 is cut into a desired size. Note that a decurling unit (not shown) that removes curling of the recording paper 16 due to being loaded on the roll paper 26 may be arranged in the vicinity of the upstream of the cutter 24.

  As shown in FIG. 2, the belt transport unit 18 has a structure in which an endless belt 38 is wound between rollers 30, 32, 34, and 36, and at least a portion facing the recording head 12 is a horizontal surface (flat surface). It is comprised so that it may make. The power of the motor 108 (see FIG. 3) is transmitted to at least one of the rollers 30, 32, 34, and 36 around which the belt 38 is wound.

  The belt 38 has a width that is greater than the width of the recording paper 16, and the surface thereof is liquid-repellent. In addition, the liquid repellent treatment of the belt surface is generally required to have a liquid repellent performance that allows ink to move easily. For example, a contact angle of the ink to the belt surface of 120 degrees or more is preferable.

  In FIG. 1, reference numeral 82 denotes a recording paper detection unit for reading the position and size of the recording paper, reference numeral 84 denotes a recording position detection unit for determining ink ejection timing to the recording paper 16, and reference numeral 86 denotes a phase for detecting the phase of the belt 38. A detection unit 88 is a recording paper end detection unit for determining the jam of the recording paper 16 and the supply timing of the next paper. Further, the paper discharge unit 22 is provided with a discharge tray 23 for collecting the recording paper 16 on which images have been recorded.

  As shown in FIG. 2, the phase detection unit 86 of this example includes two phase detection units 86a and 86b. The belt 38 is driven in the counterclockwise direction in FIG. 2, and the recording paper 16 on the belt 38 is conveyed from right to left in FIG. Reference numeral 75 denotes an ink tray for collecting ink ejected from the recording head 12 onto the belt 38.

  As shown in FIG. 2, a linear scale 39 is attached to the belt 38, and the phase of the belt 38 can be detected by the phase detectors 86a and 86b arranged around the belt. The linear scale 39 may be provided on either the front surface or the back surface of the belt 38. The first phase detector indicated by reference numeral 86a is used for belt origin detection, and the second phase detector indicated by reference numeral 86b is used for scale detection.

  As an alternative to the second phase detector 86b, a phase can be managed by attaching a rotary encoder to any one of the rollers 30, 32, 34, and 36.

  Signals (signals for detecting the phase of the belt 38) obtained from these means are sent to the print control unit 110 (preliminary ejection control unit 111) shown in FIG. 3, and the ejection of the recording head 12 is controlled. It can be landed on substantially the same point on the belt 38.

  FIG. 3 is a principal block diagram showing the system configuration of the image forming apparatus 10. The image forming apparatus 10 includes a communication interface 100, a system controller 102, a print control unit 110, a head driver 112, a sensor unit 114, a maintenance unit 116, a cutter 24, and the like.

  The communication interface 100 is an interface unit that receives image data sent from the host computer 120. As the communication interface 100, a serial interface such as USB, IEEE1394, Ethernet (registered trademark), a wireless network, or a parallel interface such as Centronics can be applied. Image data sent from the host computer 120 is taken into the image forming apparatus 10 via the communication interface 100 and temporarily stored in the image memory 104. The image memory 104 is a storage unit that temporarily stores input image data. The image data is read and written through the system controller 102.

  A system controller 102 is a control unit that controls each unit such as the communication interface 100, the image memory 104, and the motor driver 106. The system controller 102 includes a central processing unit (CPU) and its peripheral circuits. The system controller 102 performs communication control with the host computer 120, read / write control of the image memory 104, and the like, and the recording paper 16 by the motors 108 and 109. A control signal for controlling the conveyance of the image is generated.

  The motor driver 106 is a driver (drive circuit) that drives the motors 108 and 109 in accordance with instructions from the system controller 102.

  The print control unit 110 is a control unit that controls each unit such as the head driver 112 and the cutter 24 based on the detection result from the sensor unit 114. The print control unit 110 performs processing such as various processes for generating a signal for image formation control from the image data in the image memory 104 according to the control of the system controller 102, and the generated image formation control signal (image data). Is supplied to the head driver 112. The head driver 112 drives the recording head of each color (K, C, M, Y) of the recording head 12 based on the image data given from the print control unit 110.

  Further, the print control unit 110 includes a preliminary ejection control unit 111 for controlling the recovery operation of the recording head 12 including the preliminary ejection operation. The preliminary ejection control unit 111 controls each unit such as the motor driver 106, the head driver 112, and the maintenance unit 116 based on the detection result from the sensor unit 114.

  The maintenance unit 116 includes a cleaning blade for wiping the nozzle surface of the recording head 12 and a driving mechanism for the wiping means, and a cap closely attached to the nozzle surface, and a suction pump in the recording head 12 (in the pressure chamber 52). And suction means for sucking ink.

  The sensor unit 114 provided in the print control unit 110 is a block including the recording paper detection unit 82, the recording position detection unit 84, the phase detection unit 86, the recording paper end detection unit 88, and the ejection failure detection device 89 described above. The detection results detected by these detection units are provided to the print control unit 110 and the preliminary ejection control unit 111.

In the print control unit 110 (including the preliminary ejection control unit 111), predetermined calculation processing is performed based on the detection results detected by each detection unit, and these processing results are provided to the system controller 102. That is, the cutting timing of the recording paper 16 by the cutter 24 is determined based on the detection result in the recording paper detection unit 82, and the ink ejection timing is determined based on the detection result of the recording position detection unit 84. . Further, the driving position of the belt 38 is detected based on the detection result of the phase detection unit 86, and based on the detection result of the recording paper end detection unit 88, it is determined whether the recording paper 16 is jammed or the next sheet is detected. Supply timing and the like are determined. In addition to this, after the time or the number of times of recording determined in advance by the preliminary ejection control unit 111, a nozzle cleaning operation described later is performed. Even when the occurrence of a nozzle failure is detected based on the detection result of the discharge failure detection device 89 in FIG. 3, the preliminary discharge control unit 111 performs a nozzle cleaning operation (a recovery operation by the maintenance unit 116 as necessary). Control is performed.

  Next, the operation of the image forming apparatus 10 configured as described above will be described.

  In FIG. 3, image data to be printed is input from the host computer 120 via the communication interface 100 and stored in the image memory 104. The system controller 102 drives the motor 109 (108) via the motor driver 106, pulls out the recording paper 16 from the roll paper 26 shown in FIG. The system controller 102 causes the cutter 24 to cut the recording paper 16 to a paper size predetermined by the image data via the print control unit 110, and the cut recording paper 16 is sent to the belt conveyance unit 18. Next, the system controller 102 controls the rotation of the rollers 30, 32, 34, and 36 based on the detection result from the sensor unit 114. As a result, the recording paper 16 is conveyed on the belt 38.

  When the conveyed recording paper 16 reaches the recording head 12, recording on the recording paper 16 is performed. That is, the image data stored in the image memory 104 in FIG. 3 is sent to the print control unit 110 and converted into dot data for each ink color via the head driver 112. The head driver 112 captures this dot data and generates a drive control signal for the recording head 12. When the drive control signal generated by the head driver 112 is applied to the nozzles of the recording head 12, ink is ejected from the nozzles onto the recording surface of the recording paper 16.

  The recording head 12 controls the ink discharge timing from the recording head in synchronization with the conveyance speed of the recording paper 16 on the basis of the detection result from the recording position detection unit 84 of the sensor unit 114, thereby conveying the recording paper 16. An image can be formed on the recording paper 16 without stopping the operation. The recording paper 16 on which the image has been recorded is continuously conveyed by the belt 38 and discharged from the paper discharge unit 22.

  Next, preliminary discharge will be described. During printing or standby, the frequency of use of specific nozzles decreases, and if ink is not ejected for a certain period of time, the ink solvent near the nozzles evaporates and the ink viscosity increases. In such a state, even if an actuator (not shown) of the recording head 12 is operated, ink cannot be ejected from the nozzles. Prior to this state, the actuator is operated within the range of the viscosity that can be discharged by the operation of the actuator, and preliminary discharge is performed to discharge the deteriorated ink (ink near the nozzle whose viscosity has increased).

  Preliminary ejection as described below is performed after a predetermined non-operating nozzle elapsed time or the number of recordings has elapsed, or when an ejection failure is detected by the ejection failure detection device 89 of FIG.

That is, when the recording operation is continuously performed until the predetermined time or the predetermined number of times is reached, or when the discharge failure detection device 89 detects the discharge failure of the nozzles, the print control unit 110 performs the next conveyance. The leading edge of the recording paper 16 is detected by the recording paper detector 82 (see FIG. 1), and the rear end of the recording paper 16 currently being conveyed has passed the position facing the recording head 12K for discharging black ink. Later, ink that does not contribute to printing is ejected from all nozzles in the recording head 12K via the head driver 112. That is, the gap between the recording papers 16 (paper) is formed at a position facing the recording head 12 using the conveyance interval between the trailing edge of the recording paper 16 currently being conveyed and the leading edge of the recording paper 16 to be conveyed next. In between, the ink that does not contribute to printing is ejected from all the nozzles of the recording head 12K toward the belt 38 between the sheets. The preliminarily ejected ink is ejected onto the belt 38, thereby removing unused and dried ink or defective ink whose viscosity has changed from the nozzles of the recording head 12K.

  After the preliminary ejection by the recording head 12K in this manner, similarly, as the inter-sheet position sequentially moves to the position facing the recording heads 12C, 12M, 12Y, the belt 38 between the sheets is moved. The inks that do not contribute to printing are ejected from the recording heads 12C, 12M, and 12Y, and the same preliminary ejection is performed by the recording heads of the respective colors. At this time, the preliminary ejection control unit 111 of the print control unit 110 receives the ink from the other recording heads 12C, 12M, and 12Y at substantially the same droplet deposition location as the landing on the belt 38 from which the ink by the recording head 12K was ejected. The ink discharge timing is controlled so that the ink is discharged. That is, based on the detection result of the phase detector 86, the ink of each of the new recording heads 12C, 12M, and 12Y is repeatedly landed at substantially the same droplet deposition location as the ink landing by the recording head 12K on the belt 38. . Thereby, the inks of the respective colors can be combined and aggregated on the belt 38.

  Next, as the belt 38 is driven, the combined and agglomerated ink is rotationally driven together with the belt 38 and conveyed to the belt turning position 38a. Then, as shown in FIG. 1, the ink adhering to the belt 38 naturally falls at the belt turning position, is removed from the belt surface, and is collected in the ink tray 75. Here, in FIGS. 1 and 2, the belt direction is bent at an angle of 90 degrees, but the angle is arbitrary as long as the belt turns downward.

  As described above, according to the image forming apparatus 10 according to the embodiment of the present invention, a new surface is formed on the belt surface of the belt 38 that has been subjected to the liquid repellent treatment at substantially the same droplet deposition location as the landing of ink by preliminary ejection. Since ink by preliminary ejection is repeatedly landed, the ink can be coalesced and aggregated on the belt surface. Therefore, the combined and agglomerated large ink can be removed by dropping naturally due to the effect of the liquid repellency treatment on the belt surface at the belt 38 turning position, and the ink recoverability can be improved.

  In addition, since preliminary ejection can be performed at an arbitrary position on the belt 38, preliminary ejection can be performed at an arbitrary position on the belt, and productivity in image formation of recording paper can be improved.

  Next, a second embodiment of the image forming apparatus according to the present invention will be described in detail.

  The image forming apparatus according to the present embodiment is obtained by changing the configuration of the belt 38 of the belt conveyance unit 18 in the image forming apparatus 10 described above, and the other configurations are the image forming apparatus according to the first embodiment described above. The detailed description other than the belt conveyance unit will be omitted.

  As shown in FIG. 4A, the belt conveyance unit 50 used in the image forming apparatus according to the present embodiment uses an endless belt 54 in which a large number of dimples 52 are formed on the belt surface on the recording head 12 side. , 32, 34, and 36. The belt 54 has a width that is wider than the predetermined maximum size of the recording paper 16, and the surface thereof is liquid-repellent. As shown in FIG. 4B, the dimple 52 has an XX cross-section formed in a waveform shape in which a peak portion 52a and a valley portion 52b are continuous, and has a similar waveform shape in a direction perpendicular to XX. It has become.

  The portion of the upper portion of the peak portion 52a that contacts the recording paper 16 is formed in a slightly flat shape as compared with the valley portion 52b. Note that the inner surface of the dimple 52 is also subjected to a liquid repellent process.

  The ink deposited on the belt surface of the belt 38 enters the valley 52b of the dimple 52 and then aggregates at the bottom of the valley 52b (reference numeral 55). It is possible to promote the coalescence and aggregation of the ink droplets that have been ejected onto the belt surface by the dimples 52, and even when the amount of ink that has been ejected onto the belt surface of the belt 38 is very small, the ink can be coalesced at the valley portion 52b. Thereafter, as the belt 54 is driven, the combined and aggregated ink is rotationally driven together with the belt 54 and conveyed to the belt turning position 54a. The ink adhering to the belt 54 naturally falls at the belt turning position 54a, is removed from the belt surface, and is collected in the ink tray 75.

  According to the image forming apparatus having such a configuration, the ink coalescence and aggregation can be promoted by the ink aggregation recess formed on the belt surface of the belt 54, and the ink collecting effect can be improved.

  If a large number of dimples 52 are arranged in a staggered manner and the phase detector 86 is used, it is possible to preliminarily eject ink droplets preliminarily ejected from all nozzles and capture them.

  Here, the configuration of the concave portion for aggregating ink formed on the belt surface is not limited to the dimple 52 described above. For example, as shown in the belt 60 of the belt conveyance unit 56 in FIG. You may form the groove | channel 58 in the orthogonal direction. As shown in FIG. 5B, the groove 58 has a cross section (YY cross section) formed in a rectangular shape in which a crest 58a and a trough 58b are continuous. As shown in FIG. A bottom 58c of the groove 58 is formed so as to be inclined toward the approximate center of the belt 60 in a cross section in the orthogonal direction (Z-Z cross section), and a liquid reservoir 59 is formed. As a result, the ink that has been ejected from the recording head 12 into the groove 58 of the belt 60 is promoted to coalesce and aggregate in the liquid reservoir 59 (reference numeral 55), thereby improving the ink collecting effect.

  The configuration of the bottom portion 58c of the groove 58 is a configuration in which the bottom portion 58c is inclined toward one end in the width direction of the belt 60 in a cross section (Z-Z cross section) perpendicular to the transport direction as shown in FIG. Also good. Also with the groove 58 having such a configuration, the ink ejected into the groove 58 can be coalesced and aggregated at one end of the groove 58.

  Next, a third embodiment of the image forming apparatus according to the present invention will be described in detail with reference to FIG.

  The image forming apparatus according to the third embodiment of the present invention is obtained by changing the configuration of the belt conveyance unit 18 in the image forming apparatus 10 described above, and the other configurations are the images according to the first embodiment described above. It is almost the same as the forming apparatus 10.

  As shown in FIG. 6A, a belt conveyance unit 70 used in the image forming apparatus according to the present embodiment includes a belt 72 wound around rollers 30, 32, 34, and 36, and a guide for curving the belt 72. A roller 74 and an auxiliary roller 76 are included.

  The belt 72 has a width that is greater than that of the recording paper 16, and its surface is liquid repellent. The guide roller 74 and the auxiliary roller 76 are rotatably supported from the image forming apparatus main body side. The auxiliary roller 76 forms the belt 72 on a flat surface at a position below the recording head 12. By this guide roller 74, a portion of the belt 72 facing the recording head 12 is bent via the auxiliary roller 76. Ink is aggregated in the curved portion of the belt 72 having such a configuration. The recording paper 16 conveyed to the belt conveyance unit 70 is conveyed in contact with the flat surface of the belt 72 above the belt conveyance unit 70.

  As shown in FIG. 6B, the guide roller 74 is formed with a spiral groove 74a on the peripheral surface thereof, and the ink aggregated on the curved portion of the belt 72 enters the spiral groove 74a. Reference numeral 77 denotes an ink tray for collecting ink falling from the end of the guide roller 74.

  The operation of the image forming apparatus configured as described above will be described. Ink is preliminarily ejected from the recording head 12 toward the curved portion. When the guide roller 74 in the bending portion is rotated, the ink in the bending portion is swept out of the belt 72 along the spiral groove 74a by the pushing action by the spiral groove 74a. Thereafter, the ink falls from the end of the guide roller 74 and is collected in the ink tray 77.

  The curved portion is preferably provided on the opposite side of the head with respect to the recording paper conveyance path at a position downstream of the position facing the head (near the head).

  As described above, according to the image forming apparatus of the present embodiment, the ink in the curved portion can be ejected along the guide roller 74, and the ink can be removed from the curved portion of the belt 72.

  The belt conveyance unit in the image forming apparatus according to the fourth embodiment of the present invention is configured to incline the belt conveyance unit 18 shown in FIG. 2A by θ: 1 to 10 degrees with respect to the horizontal plane in a direction orthogonal to the conveyance direction. It has been made. Accordingly, since the recording head 12, the belt 38, the rollers 30, 32, 34, and 36 are inclined, the ink that has landed on the belt surface can be dropped from the belt surface along the inclination. Since both the recording head 12 and the belt 38 are inclined at the same inclination angle θ, the clearance between the recording head 12 and the recording paper 16 can be kept constant, and the recording paper for ink ejected from the recording head 12 can be maintained. The timing of droplet ejection to 16 does not occur and image quality deterioration can be prevented. The inclination angle θ is set to 1 to 10 degrees so as not to hinder the ejection of ink from the recording head 12. Thereby, it is possible to achieve both ink ejection performance and ink recovery performance.

  Further, at the belt turning position 38a in FIG. 2, when the direction of the belt 38 is downward, a treatment liquid made of water, alcohol, or other ink-soluble liquid is discharged toward the belt 38 from a nozzle (not shown). The ink on the belt 38 may be washed away. Note that the processing liquid may be discharged from the recording head 12 toward the belt 38. Further, a dedicated head for discharging the processing liquid may be provided on the downstream side in the transport direction from the recording head 12. Moreover, it is good also as a structure which blades ink or an ink, and a process liquid with elastic members, such as rubber | gum, in a downward part.

1 is a side view showing an image forming apparatus according to an embodiment of the present invention. 1 is a perspective view of a belt conveyance unit used in an image forming apparatus according to an embodiment of the present invention. 1 is a principal block diagram showing a system configuration of an image forming apparatus according to an embodiment of the present invention. The perspective view which shows another embodiment of the belt conveyance part used for the image forming apparatus which concerns on embodiment of this invention. The perspective view which shows another embodiment of the belt conveyance part used for the image forming apparatus which concerns on embodiment of this invention. The perspective view which shows another embodiment of the belt conveyance part used for the image forming apparatus which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus, 12 ... Recording head, 16 ... Recording paper, 18 ... Belt conveyance part, 38, 54, 60, 72 ... Belt, 39 ... Linear scale, 52 ... Dimple, 58 ... Groove, 74 ... Guide roller, 74a ... spiral groove, 76 ... auxiliary roller, 82 ... recording paper detection unit, 84 ... recording position detection unit, 86 ... phase detection unit, 88 ... recording paper end detection unit, 102 ... system controller, 110 ... print control unit, 111 ... Preliminary discharge controller

Claims (3)

A conveyor belt for conveying a recording medium, an image forming apparatus having a plurality of recording heads for forming an image by ejecting droplets against the recording medium on the conveyance belt,
The entire surface of the conveying belt that conveys the recording medium is subjected to liquid repellent treatment , and the belt surface of the conveying belt has a concave curve corresponding to each recording head by the winding of the conveying belt. Part is formed,
Wherein the curved portion is an image forming apparatus characterized by guide rollers for guiding the droplets aggregated into the curved portion is disposed. The image forming apparatus according to claim 1, wherein the curved portion is provided on a downstream side of a position facing the recording head. The image forming apparatus according to claim 1, wherein a spiral groove is formed on a peripheral surface of the guide roller.

Images