JP5172361B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that forms an image on a recording medium.

  In recent years, many ink jet printers that form images by ejecting ink onto a recording medium have become widespread. In recent years, printers that employ a fixed inkjet head that covers a width perpendicular to the conveyance direction of a recording medium, that is, a so-called line head, are commercially available for high-speed printers for office use. In such an ink jet printer, a conveyance belt that conveys a recording medium is positioned opposite to an ink jet head that ejects ink. When the recording medium carried on the conveyance belt is conveyed to a position facing the ink jet head, the ink jet head ejects the ink toward the recording medium to sequentially form images.

  Since the ink jet head is provided with a circuit board for controlling the ejection of ink, heat is generated on the circuit board during ink ejection, and the temperature of the ink jet head rises. In addition, the ink jet head vibrates in the process of discharging ink, and the ink jet head is heated and the temperature rises. The flow of air is small in the space where the ink jet head is arranged in the printer, and the heat of the ink jet head is not easily dissipated unless measures for heat dissipation are taken. When the temperature of the ink-jet head rises, the ink viscosity is lowered, the ink discharge port is dried, and the like, which affects the ink discharge, causing a reduction in image quality.

Therefore, Patent Document 1 describes a technique for cooling an inkjet head using a suction fan that sucks air from the back side of the transport belt through a suction hole and sucks a recording medium onto the surface of the transport belt.
JP 2007-90835 A

  However, in order to efficiently prevent the temperature rise of the inkjet head main body and the attached circuit board, there are many cases where a dedicated cooling fan or a heat radiating device is installed around the inkjet head. In this case, the installation of a cooling fan and a heat radiating device is costly.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to easily cool an inkjet head without installing a cooling fan or the like dedicated to the inkjet head.

An image forming apparatus according to a first aspect of the present invention has a plurality of suction holes penetrating the front surface and the back surface, a conveyance belt for carrying and conveying a recording medium on the front surface, and at least first and second recordings An image forming means for forming an image on a recording medium transported by the transport belt, the head being arranged in parallel along the transport direction of the recording medium, and air from the back side of the transport belt through the suction hole And a suction means for adsorbing the recording medium to the surface of the conveying belt, an inflow port near the suction means, a discharge port near the image forming means, and suction by the suction means Air is sent from the inflow port to the discharge port, and the discharge port includes one side duct and the other side duct arranged toward the first and second recording heads, and the one side The duct is Arranged on one side in the main scanning direction perpendicular to the conveying direction of the feed belt, the other side duct is disposed on the other side of the main scanning direction, between said first recording head the second recording head The outlets of the one side duct and the other side duct are oriented.

  According to this configuration, since the duct sucks the air sucked by the suction unit to the image forming unit side, the temperature of the main body of the image forming unit (for example, an ink jet head) or the circuit board attached to the image forming unit is increased. Can be prevented. Further, since it is not necessary to install a dedicated cooling fan or heat radiating device for cooling the image forming means, the cost can be reduced.

The invention according to claim 2 is the image forming apparatus according to claim 1, wherein each of the one side duct and the other side duct is fixedly arranged with one end as the inlet close to the suction means. A first duct provided and a second duct having one end as the discharge port fixedly disposed in the immediate vicinity of the image forming means, and when the air is sucked by the suction means, The other ends of the first duct and the second duct are joined to each other, and the air sucked by the suction means is sent from one end of the first duct to one end of the second duct.

  According to this configuration, the duct can be separated into the first duct and the second duct in accordance with the movement of the suction unit and the transport unit or the image forming unit. Thereby, when attaching the cap which prevents drying etc. to the printing surface of an image forming means, a cap can be attached without being disturbed by a duct.

The invention according to claim 3 is the image forming apparatus according to claim 1, wherein the inlets of the one-side duct and the other-side duct are fixedly disposed in the immediate vicinity of the suction means. Or the discharge ports of the one-side duct and the other-side duct are fixedly disposed in the immediate vicinity of the image forming means.

  Here, of the inlet and the outlet of the duct, a port that is not fixedly disposed in the immediate vicinity of the suction unit or the image forming unit is in a released state, or is not fixedly disposed with the suction unit or the image forming unit. To do. Thereby, the duct can follow the movement in accordance with the movement of the suction unit and the conveying unit or the image forming unit. Accordingly, when a cap for preventing drying or the like is attached to the printing surface of the image forming unit, a space can be provided between the printing surface of the image forming unit and the conveying unit without being obstructed by the duct, and the cap is attached. can do.

Further, an invention according to claim 4, an image forming apparatus according to any one of claims 1 to 3, wherein the recording head is characterized in that an ink jet head.

  According to this configuration, the image forming apparatus having the ink jet head can enjoy the operational effects of the first to third aspects.

  According to the present invention, the temperature of the main body of the image forming means (for example, the ink jet head) and the circuit board attached to the image forming means is obtained by sending the air sucked by the suction means to the image forming means side. The rise can be prevented. Further, since it is not necessary to install a dedicated cooling fan or heat radiating device for cooling the image forming means, the cost can be reduced.

  Since the duct is separated into the first duct and the second duct as the suction unit and the conveying unit or the image forming unit moves, when the cap for preventing the drying or the like is attached to the printing surface of the image forming unit, Caps can be attached without being disturbed by the duct.

  Alternatively, among the inflow port and the discharge port of the duct, a port that is not fixedly disposed in the immediate vicinity of the suction unit or the image forming unit is in a released state, or is not fixedly disposed with the suction unit or the image forming unit. As the suction unit and the conveyance unit or the image forming unit move, the duct can follow the movement. Therefore, when the cap is attached to the printing surface of the image forming unit, a space can be provided between the printing surface of the image forming unit and the conveying unit without being obstructed by the duct, and the cap can be attached. .

  Hereinafter, an embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings. The image forming apparatus according to the present invention can be applied to an electronic device such as a printer, a copying machine, a facsimile machine, or a multifunction machine having these functions. In the following embodiments, an ink jet printer will be described as an example of an image forming apparatus. However, an image that includes a suction fan on the back side of a conveyance belt that conveys a recording medium and forms an image using a print head. Any forming apparatus may be used. An ink jet printer that performs color printing using a plurality of ink jet heads will be described as an example, but an ink jet printer for monochromatic printing may be used.

  FIG. 1 is a schematic cross-sectional view of an image forming apparatus 1 in the present embodiment. In the following description, in the drawings, the conveyance direction of the recording medium is defined as the X-axis direction or the sub-scanning direction, and the direction orthogonal to the conveyance direction is defined as the Y-axis direction, the main scanning direction, the printing width direction, or the recording medium width direction. To do. A direction orthogonal to the XY plane is defined as a Z-axis direction or a vertical direction. 1 is a cross-sectional view when viewed from the main scanning direction side.

  The image forming apparatus 1 includes a paper cassette 11, a pickup roller 12, a transport roller pair 13, a suction roller 14, a transport belt 15, a transport plate 16, a suction fan (suction unit) 17, an ink jet head (image forming unit) 18, and a cleaning device. 21, a discharge roller pair 25 and a discharge tray 26 are provided.

  A recording medium P before printing is stacked and stored in the paper cassette 11, and the recording medium P is picked up one by one by driving the pickup roller 12 and sent out to the first paper feed conveyance path 31. The transport roller pair 13 transports the recording medium P that has passed through the first paper feed transport path 31 to the second paper feed transport path 32.

  The recording medium P that has passed through the second paper feed conveyance path 32 is conveyed to a position facing the ink discharge port of the inkjet head 18 via the nip portion between the suction roller 14 and the conveyance belt 15. The surface of the suction roller 14 is in contact with the transport belt 15, and the recording medium P is pressed against the transport belt 15 and sucked. For example, a sheet made of dielectric resin is used as the conveyor belt 15, and an endless belt having both ends overlapped and joined or a seamless belt is used. The conveyor belt 15 is stretched over a paper feed side (upstream side) driven roller 22, a paper discharge side (downstream side) drive roller 20, and a tension roller 19, and the drive roller 20 is counterclockwise on the paper surface. When it rotates around, the driven roller 22 rotates in conjunction with it, and the conveyor belt 15 rotates in the direction of the arrow Y1. The tension roller 19 is a roller that applies a force so that the conveyor belt 15 does not sag between the driving roller 20 and the driven roller 22.

  The conveyance plate 16 is for guiding the rotation of the conveyance belt 15. The suction fan 17 sucks air through a plurality of suction holes (not shown) formed in the transport belt 15 and a plurality of suction holes 16 a formed in the transport plate 16. A suction hole (not shown) formed in the transport belt 15 and a suction hole 16a formed in the transport plate are formed over a width equal to or larger than the maximum width of the recording medium P. Then, when the suction fan 17 sucks air from the back side of the transport belt 15, the recording medium P is attracted and fixed to the surface of the transport belt 15. A plurality of suction fans 17 are arranged on the back side of the conveyor belt 15 so that air is sucked from the entire surface of the conveyor belt 15 facing the inkjet head 18. Hereinafter, a portion constituted by the conveyance belt 15, the suction fan 17, the driven roller 22, the tension roller 19, the driving roller 20, the cleaning device 21, and the like is referred to as a “belt unit 100”.

  The inkjet head 18 includes, for example, a yellow inkjet head 18Y, a magenta inkjet head 18M, a cyan inkjet head 18C, and a black inkjet head 18K. Each inkjet head is fixed by a head mounting plate 41. Then, cyan, magenta, yellow, and black inks are ejected toward the recording medium P to sequentially form images. Examples of the ink discharge method of the ink jet head 18 include a piezo method in which ink is ejected using a piezo element, and a thermal ink jet method in which bubbles are generated by a heating element and ink is discharged with the pressure. Hereinafter, a portion constituted by the ink jet head 18 and the head mounting plate 41 is referred to as a “head unit 200”.

  The cleaning device 21 is for removing ink adhering to the surface of the transport belt 15. The recording medium P on which the image has been formed passes through the discharge conveyance path 24 and is discharged to the discharge tray 26 by the discharge roller pair 25.

  The duct 51 and the duct 52 are pipes for sending the air sucked by the suction fan 17 to the inkjet head 18. The duct 51 is fixedly disposed near the suction fan 17 on the paper feed side (upstream side) of the inlet 51, and the discharge port is fixed near the yellow inkjet head 18Y and the magenta inkjet head 18M. It has the 2nd duct 51b arrange | positioned, and is comprised. When air is sucked by the suction fan 17, the end opposite to the inlet of the first duct 51 a (hereinafter referred to as “joint”) and the end opposite to the outlet of the second duct 51 b (hereinafter referred to as “joint”). And the first duct 51a and the second duct 51b are integrated, and the sucked air is sent from the inlet of the first duct 51a to the outlet of the second duct 51b.

  Similarly, the duct 52 has a first duct 52a in which the inlet is fixedly disposed in the immediate vicinity of the suction fan 17 on the discharge side (downstream side), and the discharge port of the cyan inkjet head 18C and the black inkjet head 18K. It has the 2nd duct 52b currently fixedly arrange | positioned immediately. When air is sucked by the suction fan 17, the end (joint port) opposite to the inflow port of the first duct 52a and the end opposite to the discharge port (joint port) of the second duct 52b are joined. The first duct 52a and the second duct 52b are integrated, and the sucked air is sent from the inlet of the first duct 52a to the outlet of the second duct 52b.

  In FIG. 1, only the duct 51 and the duct 52 disposed on the front side in the print width direction from the transport belt 15 are illustrated. However, a similar duct is located on the other side of the print width direction from the transport belt 17 (the transport belt 17 is connected). It is also disposed on the side facing the ducts 51 and 52. Further, the number of ducts to be arranged is not limited to this, and may be appropriately arranged according to the number and size of the heads included in the inkjet head 18.

  2 to 4 are schematic side views of the belt unit 100 and the head unit 200 when the image forming apparatus 1 when the suction fan 17 is driven is viewed from the sub-scanning direction side (the conveyance direction downstream side). . For convenience of explanation, the cleaning device 21 is not shown. In addition, a plurality of suction holes 15a are formed on the entire surface of the belt so that the recording medium can be adsorbed and fixed to the transport belt 15, but in FIGS. 15a is illustrated. Similarly, the plurality of suction holes 16a formed in the transport plate 16 are not shown in FIGS. 2 to 4 for convenience, but are actually formed over the entire surface of the transport plate 16 as shown in FIG. Yes.

  As shown in FIG. 2, a duct 53 is disposed on the side facing the duct 52 with the conveyance belt 15 interposed therebetween. The duct 53 includes a first duct 53 a and a second duct 53 b, and each element is arranged in the same manner as the duct 51 and the duct 52. A duct (not shown) is also disposed on the side facing the duct 51 (position adjacent to the duct 53 in the sub-scanning direction) across the transport belt 15. Hereinafter, all the ducts including the ducts 51, 52, and 53 are collectively referred to as “duct 50”.

  When the suction fan 17 is driven, air is sucked through the suction holes 15a of the transport belt 15 and the suction holes 16a (not shown in FIGS. 2 to 4) of the transport plate 16. The sucked air flows below the suction fan 17. An arrow Y2 indicates the flow of air sucked by the suction fan 17. The air that has entered from the inlet of the duct 50 flows upward in the duct 50 as indicated by an arrow Y3, and flows out from the discharge port toward the inkjet head 18 as indicated by an arrow Y4. Thus, the duct 50 sends the air sucked by the suction fan 17 to the ink jet head 18 side, so that the temperature of the main body of the ink jet head 18 and the circuit board attached to the ink jet head 18 can be prevented. Further, since it is not necessary to install a dedicated cooling fan or heat radiating device for cooling the inkjet head 18, the cost can be reduced.

  When the suction fan 17 is not driven (air is not sucked), the recording medium P is not transported, that is, ink is not ejected from the inkjet head 18. At this time, a cap is attached to the ink discharge port in order to prevent drying of the ink discharge port of the inkjet head 18. At this time, since the ink-jet head 18 is not driven to eject ink, a drive current for driving the ink-jet head 18 does not flow through the circuit board. For this reason, since there is no heat generation of the circuit board due to the drive current, cooling beyond natural heat dissipation is unnecessary.

  FIG. 3 schematically shows the belt unit 100 and the head unit 200 when the image forming apparatus 1 is viewed from the sub-scanning direction side (downstream side in the transport direction) when the cap 42 is attached to the ink discharge port of the inkjet head 18. It is a side view. When image formation is performed by the inkjet head 18, the cap 42 is stored in a space (not shown) that does not interfere with image formation. For example, when in a standby state or when the power of the image forming apparatus 1 is turned off, the belt unit 100 moves downward (−Z direction), and the stored cap moves to the ink discharge port of the inkjet head 18 and is attached. Is done.

  The inlet of each first duct of the duct 50 is fixedly disposed in the vicinity of the suction fan 17 (to the belt unit 100), and the outlet of each second duct of the duct 50 is in the vicinity of the inkjet head 18 ( The head unit 200 is fixedly disposed. As the belt unit 100 moves downward, the first ducts of the duct 50 also follow the belt unit 100 and move downward. In this case, the joint 521a of the first duct 52a and the joint 521b) of the second duct 52b are separated as shown in FIG. Then, when the belt unit 100 moves to the position at the time of image formation, the first ducts of the ducts 50 also follow and join with the joints of the second ducts so that the first ducts and the second ducts are integrated. (State of FIG. 2).

  As described above, when the cap 42 is attached to the ink discharge port, the duct 50 is separated into the first duct and the second duct as the belt unit 100 moves downward. Since the space can be provided, the cap 42 can be attached to the ink discharge port without being obstructed by the duct 50.

  Although it has been described that the belt unit 100 moves downward when the cap 42 is attached to the ink discharge port, the belt unit 100 is fixed and the head unit 200 moves upward (+ Z direction). May be. Alternatively, the belt unit 100 may move downward and the head unit 200 may move upward.

  In addition to the configuration in which the duct 50 is separated into the first duct and the second duct as the belt unit 100 moves, a configuration as shown in FIG. 4 may be used. FIG. 4 is a schematic side view of the belt unit 100 and the head unit 200 when the image forming apparatus 1 is viewed from the sub-scanning direction side (upstream side in the transport direction) when the cap 42 is attached to the ink discharge port. . Only differences from FIG. 3 will be described.

  The duct 61 and the duct 62 (hereinafter collectively referred to as “duct 60”) do not have a joint port like the duct 50, and are integrally configured. It is assumed that a plurality of ducts are arranged around the belt unit 100 as in the configuration shown in FIGS. 1 and 2. The discharge port 61 b of the duct 61 and the discharge port 62 b of the duct 62 (hereinafter collectively referred to as “discharge port 60 b”) are fixedly disposed in the immediate vicinity of the head unit 200. On the other hand, the inlet 61a of the duct 61 and the inlet 62a of the duct 62 (hereinafter collectively referred to as “inlet 60a”) are positioned in the immediate vicinity of the suction fan 17 when the suction fan 17 is in a driving state. It is not fixedly arranged and is in a released state or is fixedly arranged on a part other than the belt unit 100.

  With such a configuration, when the cap 42 is mounted on the ink discharge port, only the belt unit 100 can be moved, and the cap can be mounted on the ink discharge port regardless of the piping of the duct 60. . Note that the inflow port 60a of the duct 60 may be fixedly disposed in the immediate vicinity of the suction fan 17, and the discharge port 60b may be in a released state.

FIG. 3 is a schematic cross-sectional view of the image forming apparatus viewed from the main scanning direction side. FIG. 3 is a schematic side view of a belt unit and a head unit when the image forming apparatus is viewed from the sub-scanning direction side when a suction fan is driven. FIG. 4 is a schematic side view of the belt unit and the head unit when the image forming apparatus is viewed from the sub-scanning direction side when a cap is attached to the ink discharge port. The modification of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 11 Paper cassette 12 Pickup roller 13 Conveying roller pair 14 Adsorption roller 15 Conveying belts 15a and 16a Suction hole 16 Conveying plate 17 Suction fan 18 Inkjet head 19 Tension roller 20 Driving roller 21 Cleaning device 22 Driven roller 25 Discharge roller pair 26 Discharge tray 41 Head mounting plate 42 Cap 51, 52, 53, 61, 62 Duct 100 Belt unit 200 Head unit

Claims (4)

A plurality of suction holes penetrating the front surface and the back surface, a transport belt for carrying and transporting a recording medium on the front surface,
At least first and second recording heads arranged in parallel along the conveying direction of the recording medium, and image forming means for forming an image on the recording medium conveyed by the conveying belt;
A suction means for sucking air from the back surface side of the transport belt through the suction hole and sucking the recording medium onto the surface of the transport belt;
An inflow port is provided near the suction unit, a discharge port is provided near the image forming unit, and air sucked by the suction unit is sent from the inflow port to the discharge port. One side duct and the other side duct disposed toward the first and second recording heads;
With
The one side duct is disposed on one side of the main scanning direction orthogonal to the transport direction of the transport belt, and the other side duct is disposed on the other side of the main scanning direction,
An image forming apparatus in which discharge ports of the one side duct and the other side duct are oriented between the first recording head and the second recording head. Each of the one side duct and the other side duct has a first duct in which one end as the inflow port is fixedly disposed in the vicinity of the suction unit, and one end as the discharge port is fixed in the vicinity of the image forming unit. A second duct disposed,
When the air is sucked by the suction means, the other ends of the first duct and the second duct are joined together, and the air sucked by the suction means is sent from one end of the first duct to the second duct. The image forming apparatus according to claim 1, wherein the image forming apparatus is sent to one end of the image forming apparatus. The one or each of the inlet side duct and the other duct is fixed arranged in the immediate vicinity of the suction means, or each of the outlet of the one side duct and the other side duct of the image forming means The image forming apparatus according to claim 1, wherein the image forming apparatus is fixedly disposed most recently. The image forming apparatus according to claim 1, wherein the recording head is an inkjet head.

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