JP4886567B2 - Inkjet recording device - Google Patents

Description

  The present invention relates to an ink jet recording apparatus that performs recording by discharging ink from a recording head to a recording medium.

  Recording devices such as printers, copiers, and facsimiles are configured to record an image on a recording medium by a recording head based on image information, and are used as a single recording device or an output device of a computer or a workstation. ing. There are various recording systems such as an inkjet system, a laser beam system, and a thermal system. The scanning method includes a serial type in which main scanning in the direction intersecting the conveyance direction of the recording medium and sub scanning in the conveyance direction are alternately repeated, and a line type in which recording is performed only in the sub scanning. A sheet material is generally used as the recording medium, and there are various materials such as photographic printing paper, OHP sheet, and cloth in addition to paper and plastic. Further, the recording apparatus is generally provided with a transport mechanism for transporting the recording medium through the image forming unit by the recording head.

  An ink jet recording apparatus using an ink jet recording head is configured to perform recording by discharging ink from a discharge port of a recording head to a recording medium based on image information. Conventionally, since a recording apparatus is mainly used for office work, it is common to use a certain type of recording medium such as plain paper or thermal paper as the recording medium. However, in recent years, the usage forms of the recording apparatus have been increasingly diversified. For example, in addition to glossy paper and photographic paper, many types of recording media such as cloth-shaped recording media and very thick plate-shaped recording media are available. It is used. For this reason, the recording apparatus is required to be capable of recording on a wide variety of recording media. In addition, a demand for a recording medium capable of high-quality recording is rapidly progressing, and a recording apparatus capable of recording on various recording media with high-quality recording has been demanded.

  However, a wide variety of recording media have different and unique properties. For example, warp or cockling, such as those that tend to warp in the vertical direction or that tend to warp in the horizontal direction, those that tend to warp when recording ink is included, or those that tend not to correct roll wrinkles in roll paper. There are various characteristics regarding (waving). In an ink jet recording apparatus, if the recording medium has such warpage, the recording medium may come into contact with the carriage or the recording head when recording is performed. The recording head and cap may be damaged. In order to avoid such an inconvenience, it is conceivable to increase the distance between the carriage or the recording head and the recording medium.

On the other hand, in order to perform high-quality recording, it is necessary to reduce the distance between the recording head and the recording medium. The reason for this is that in order to obtain a high-quality recorded image, it is necessary to avoid the influence of the ink droplet deflection due to disturbance by shortening the flight time of the ejected ink droplet. Accordingly, it is required that the distance between the recording head and the recording medium be as small as possible in consideration of the floating of the recording medium. However, in reality, there is a problem of contact between the recording medium and the recording head as described above, and therefore the distance between them cannot be made close to one another. In order to solve such a problem, Patent Document 1 proposes a technique of pressing a part of the printing surface of a recording medium against the surface of the platen with a sheet material or a sheet metal.
JP 2004-230839 A

  However, in recent inkjet recording apparatuses, there is an increasing demand for recording without leaving margins, and there is a demand for a recording apparatus capable of borderless recording in which recording is performed to the entire edge without providing a margin area. In such a demand, if the method of pressing the recording surface with a separate member as in the prior art is employed, there is an inconvenience that no borderless recording is possible because recording cannot be performed in the pressed area. In order to cope with such inconvenience, a method of forcing the recording medium to be flattened by sucking the lower surface (non-recording surface) of the recording medium onto the platen by sucking the recording medium from the suction hole of the platen by the suction mechanism. It has been. However, this method of sucking the back surface of the recording medium has a problem that when the warp is large, the negative pressure does not reach the recording medium, and the warp cannot be suppressed.

  The present invention has been made in view of such technical problems. An object of the present invention is to provide an ink jet recording apparatus that can suppress floating of a recording medium when recording and can cope with borderless recording even when the recording medium is warped.

  The inkjet recording apparatus of the present invention includes a recording head that discharges ink to perform recording on a recording medium, a platen having a support surface that supports the recording medium at a position facing the recording head, and a suction formed on the platen. A suction means for attracting the recording medium to the platen by applying a suction force from the hole and a side end of the recording medium supported by the support surface; A flexible member that protrudes toward the recording head from the support surface of the platen, and the suction hole is formed below the side edge of the recording medium by contacting the recording medium with the recording medium. A space capable of maintaining the suction force from the space is formed, and the flexible member is displaced to the same height as the support surface against the elastic force of the flexible member by the suction force maintained in the space. The side edge of the recording medium An ink jet recording apparatus characterized by brought into close contact with the support surface.

  According to the present invention, there is provided an ink jet recording apparatus that can suppress the floating of the recording medium when performing recording even when the warping of the recording medium is large and can cope with borderless recording.

  Embodiments of the present invention will be specifically described below with reference to the drawings. Note that the same reference numerals denote the same or corresponding parts throughout the drawings. FIG. 1 is a perspective view showing a schematic configuration of an ink jet recording apparatus according to an embodiment of the present invention. In FIG. 1, a sheet-like recording medium is fed (or conveyed) in the direction of arrow A and sent to the image forming unit. The image forming unit is provided with a recording head 6 that records ink on the recording medium 4 by ejecting ink, and a platen 1 having a support surface 11 that supports the recording medium 4 at a position facing the recording head 6. The recording medium 4 inserted (or conveyed) on the support surface 11 of the platen 1 is supported in a flat state on the support surface 11 by the suction force acting through the plurality of suction holes 2 formed in the platen 1. . Above the platen 1, a carriage 5 that can reciprocate in the direction of arrow C along the guide shaft 7 is disposed, and the recording head 6 is mounted on the carriage 5.

  A plurality of ejection openings are formed in a predetermined arrangement on the face surface (lower surface in the illustrated example) facing the recording medium 4 of the recording head 6. In synchronization with the movement of the carriage 5 (and hence the movement of the recording head 6), an image is formed on the recording medium 4 by discharging ink from the discharge port of the recording head based on the image information. In the ink jet recording apparatus, it is necessary to provide a certain gap for ejecting ink droplets between the ejection surface of the recording head 6 (face surface on which ejection ports are formed) and the recording medium 4 on the platen 1. At that time, if the recording medium 4 is not flat, a predetermined gap cannot be maintained between the recording head and the recording medium. Furthermore, the recording medium may collide with the recording head or the carriage to damage the recording medium or the recorded image, or damage the recording head or the carriage. As a means for avoiding such inconvenience, a plurality of suction holes 2 are formed in a predetermined arrangement on the support surface 11 of the platen 1, and the recording medium 4 is brought into close contact with the support surface 11 by the negative pressure suction force acting through the suction holes 2. It is the composition which makes it.

  The suction means for generating a negative suction pressure in each suction hole 2 includes a suction duct 21 integrally formed on the lower side of the platen 1 and a fan (suction fan or exhaust fan) 22 attached to the suction duct 21. Yes. The suction duct 21 communicates with each suction hole 2. In the present embodiment, each suction hole 2 is formed (opened) within a range of a plurality of recesses 12 formed in the support surface 11 as shown in the figure. The fan 22 and the suction duct 21 apply suction force from the suction hole 2 formed in the platen 1 to suck the recording medium 4 sent to the image forming unit onto the platen 1 (the support surface 11). Is configured. The recording medium can be brought into close contact with the support surface 11 and flattened by the negative pressure suction force generated in the suction hole 2 by such suction means.

  Here, a conventional platen having the same configuration as described above will be described using reference examples shown in FIGS. FIG. 9 is a perspective view showing a reference example of the platen 101 having the suction holes 102. FIG. 10 is a perspective view showing a state when the recording medium 4 is conveyed on the platen 101 of FIG. FIG. 11 is a cross-sectional view showing a state when the side end of the recording medium 4 is warped in FIG. 9 to 11, the upper surface of the platen 101 is a support surface 111 that supports the recording medium 4, and a plurality of suction holes 102 are formed in the support surface 111 in a predetermined arrangement. These suction holes 102 are open within the range of the recess 112 formed in the support surface 111. A negative pressure suction force acts on each suction hole 102 through a duct (not shown) by a fan (not shown). The recording medium 4 inserted (or conveyed) and conveyed on the platen 101 is brought into close contact with the support surface 111 by a suction force acting through the suction holes 102.

  However, as shown in FIG. 11, when the side edge of the recording medium is greatly warped, a large gap is generated between the support surface 111 and the side edge of the recording medium 4. For this reason, the suction negative pressure generated in the suction hole 102 leaks from this gap, and the suction force does not effectively act on the warped portion of the recording medium, and recording is performed with the side edge portion warped. It will be. When recording is performed in a state where the recording medium 4 is not flat as described above, the recording medium may collide with the recording head or the carriage, and the recording medium may be damaged or the recording head may be damaged.

  As a means for solving such inconvenience, a method of providing a paper pressing member that presses the side end portion of the recording medium against the support surface 111 is conceivable. However, with such a method, the recording medium can be flattened, but since there is a paper pressing member at the side edge, it becomes impossible to perform borderless recording in which recording is performed without leaving a margin. The ink jet recording apparatus according to the present invention, as will be described in the following embodiments, can easily lift the recording medium even when the recording medium is warped with a simple configuration and without affecting the edgeless recording. It is configured so that it can be suppressed.

  Hereinafter, the characteristic configuration and operation of the ink jet recording apparatus according to this embodiment will be described in detail with reference to FIGS. FIG. 2 is a perspective view showing a configuration of a main part of the platen in FIG. 3 is a cross-sectional view of the platen of FIG. FIG. 4 is a perspective view showing a state when the recording medium is conveyed on the platen of FIG. FIG. 5 is a cross-sectional view of the platen and recording medium of FIG. FIG. 6 is a cross-sectional view showing a state in which the recording medium on the platen is sucked and flattened. FIG. 7 is a perspective view showing a specific example of a range in which a suction force acts on the recording medium. FIG. 8 is a cross-sectional view of FIG.

  1 to 6, the platen 1 is provided with a support surface 11 that supports the recording medium 4 inserted (or conveyed), and within the range of the plurality of recesses 12 formed on the support surface 11. A suction hole 2 is formed. In the illustrated example, a plurality of recesses 12 are formed in parallel in the width direction, and suction holes 2 are formed at two locations within the range of each recess 12. Each suction hole 2 communicates with a suction duct 21 (FIG. 1) integrally formed on the lower side of the platen 1, and a fan (suction fan or exhaust fan) 22 is attached to one end of the suction duct 21. . By operating the fan 22, a suction negative pressure (suction force) H can be generated in each suction hole 2.

  The flexible member 3 is disposed at a position corresponding to the side end of the platen 1 and corresponding to the side end of the recording medium 4 to be supported. As the flexible member 3, for example, a film material or a sheet material having excellent flexibility and mechanical properties such as PET (polyethylene terephthalate) can be used. For example, as shown in the figure, the side end portion of the recording medium 4 on the platen 1 can uniformly abut along the length direction of the recording medium and can be easily displaced downward. Selected. The position at which the flexible member 3 is disposed can be selected, for example, on the paper reference side that regulates the position in the width direction of the recording medium 4. In some cases, it is possible to select the corresponding position on the opposite side or on both sides. When the recording medium 4 is inserted or conveyed onto the platen 1, the side end of the recording medium 4 comes into contact with the top of the flexible member 3 as shown in FIGS. 4 and 5. Even when the recording medium 4 is warped, the suction force from the suction hole 2 can be maintained on the lower side of the recording medium by causing the recording medium 4 to uniformly contact the flexible member 3 over a predetermined length. A possible space X is formed.

  This space X is a substantially sealed space, and the suction negative pressure from the suction hole 2 effectively and sufficiently acts on the side end portion of the recording medium 4. When the recording medium 4 is sucked by this suction negative pressure, the flexible member 3 in contact with the recording medium is also pushed down together. As shown in FIG. 6, when the flexible member 3 is displaced to the same height as the support surface 11, the recording medium 4 is brought into close contact with the support surface 11 and becomes flat. As described above, the flexible member 3 functions as a suction assisting member that prevents the negative pressure from leaking and maintains the suction force by contacting the recording medium 4. The flexible member 3 protrudes from the support surface 11 toward the recording head 6 as shown in FIGS. 2 and 3 when the recording medium 4 is not present on the platen 1. This protrusion amount is appropriately selected in consideration of the warp of the recording medium 4, the magnitude of the suction force H, the rigidity of the recording medium 4, the elastic force of the flexible member 3, and the like.

  The operation when recording on the recording medium 4 is as follows. First, when the recording medium 4 is conveyed onto the platen 1 from the state shown in FIGS. 2 and 3, as shown in FIGS. 4 and 5, the back surface (non-recording surface) of the side end portion of the recording medium 4 is possible. It contacts the top of the flexible member 3. At the time of contact, the side edge of the recording medium 4 remains warped as shown in FIG. 5, and there is a gap (floating) between the recording medium 4 and the support surface 11. However, due to this contact, a sealed space (or a substantially sealed space) X is formed below the side end of the recording medium 4. This space X is a space in which negative pressure leakage from the side end of the recording medium 4 can be prevented, and the suction force H from the suction hole 2 can be maintained.

  If the fan 22 is operated in this state to generate a negative pressure in the suction hole 2, the suction force H acts to the side end of the recording medium 4. For this reason, as shown in FIG. 6, the side end of the recording medium 4 is sucked and moved in the direction of arrow B, and the flexible member 3 is displaced downward as the side end moves (pressing down). ). When the flexible member 3 is displaced to the same height as the support surface 11, the recording medium 4 comes into close contact with the support surface 11 and becomes flat. Thus, even when the recording medium 4 is warped, the entire recording medium 4 can be made flat. Therefore, the distance (gap) between the ink ejection portion (ejection port) of the recording head 6 and the recording surface of the recording medium 4 can be maintained appropriately and stably. Thereby, stable high-quality recording can be performed by securing an appropriate flight distance of ink droplets.

FIG. 7 is a perspective view showing a specific example of a range in which the suction force of the side end portion of the warped recording medium acts. FIG. 8 is a cross-sectional view of FIG. 7 and 8, the recording medium 4 floats from the support surface 11 of the platen 1 in a range D indicated by hatching due to warping. A range D of the floating side end portion has an E length in the conveyance (or insertion) direction A of the recording medium 4. This length E is equal to the length of the platen 1 in the direction of arrow A, and in this specific example, E = 20 mm. In the floating range D, the length of the recording medium 4 in the width direction is F. This length F is F = 50 mm in this specific example. Therefore, the area of the floating range D is D = E × F = 1000 mm ² . At this time, when the suction force from the suction hole 2 acts, the range D of the recording medium 4 becomes flat under the following conditions.

First, the flexible member 3 needs to be sufficiently bent by the load of the recording medium 4 and the negative pressure suction force. Therefore, a PET (polyethylene terephthalate) material having a thickness of 0.1 mm was used as the flexible member 3 and set so as to be displaced by 0.5 mm per 2 g load in the warp direction of the recording medium 4. For example, as shown in the figure, the shape uniformly contacts the side edge of the recording medium 4 in the length direction of the support surface 11 of the platen 1 (recording medium transport direction) and can be easily displaced downward. Shaped. The negative suction pressure H by the platen 1 was set to H = 500 Pa (= 0.05 g / mm ² ). Under such conditions, a suction operation is performed on the recording medium 4 having a floating warp of 0.5 mm at the side end. Then, the side end D where the float is generated is pressed against the flexible member 3, and the lower surface thereof is sealed. By this sealing, negative pressure leakage is prevented, and a sufficient suction negative pressure acts on the side end range D. Here, the negative pressure is H = 0.05 g / mm ² , and the area of the range D is D = 1000 mm ² . Accordingly, a suction force of H × D = 50 g acts on the range D.

  As a force against the suction force, an elastic force G of the flexible member 3 itself is generated. This elastic force G is about G = 2 g at a displacement of 0.5 mm, and 50 g of the suction force acting on the range D. Small enough compared to Accordingly, the side end portion of the recording medium 4 is in close contact with the support surface 11 of the platen 1 as shown in FIG. 6 without causing any inconvenience against the elastic force of the flexible member 3. As a result, the entire recording medium 4 is supported in a flat state. At this time, the flexible member 3 is displaced downward by the recording medium 4 and displaced to the same height as the support surface 11 of the platen 1.

  In the embodiment described above, the flexible member 3 disposed so as to be able to contact the side end portion of the recording medium 4 supported by the support surface 11 is provided. Therefore, the recording medium is in contact with the flexible member, so that a space X capable of maintaining the suction force from the suction hole 2 is formed below the side end of the recording medium. Further, the side end of the recording medium is brought into close contact with the support surface 11 against the elastic force G of the flexible member 3 by the suction force maintained in the space X. By disposing such a flexible member 3, the suction negative pressure can be prevented from escaping (leaking), and the suction negative pressure can be stably applied to a portion where the warp of the recording medium 4 occurs. The floating of the recording medium can be eliminated. The flexible member 3 can be reliably displaced to the same height as the support surface 11 of the platen. In this way, the flying distance of ink droplets during recording can be maintained at a stable and appropriate value, and high-quality recording can be performed. In addition, borderless recording without a blank area can be easily and reliably performed with a simple configuration.

  In the embodiment described above, a serial type recording apparatus using a carriage mounted with a recording head and reciprocally moved is taken as an example. The present invention can be similarly applied to other recording methods such as a line type recording apparatus that records only by sub-scanning in the direction in which the recording medium is conveyed. Further, the present invention can be similarly applied to a recording apparatus in a complex apparatus or a system configuration as well as a single recording apparatus such as a printer, a facsimile machine, and a copying machine. Further, regarding the recording medium, various materials can be used as long as image recording is possible, such as paper, plastic sheet, OHP sheet, cloth, and photographic paper.

1 is a perspective view illustrating a schematic configuration of an ink jet recording apparatus according to an embodiment of the present invention. It is a perspective view which shows the principal part structure of the platen in FIG. FIG. 3 is a cross-sectional view of the platen of FIG. 2. FIG. 3 is a perspective view showing a state when a recording medium is conveyed on the platen of FIG. 2. FIG. 5 is a cross-sectional view of the platen and recording medium of FIG. 4. It is a cross-sectional view showing a state where the recording medium on the platen is sucked and flattened. It is a perspective view shown in the specific example of the range where the suction force of the side edge part of the warped recording medium acts. It is a cross-sectional view of FIG. It is a perspective view which shows the reference example of the platen which has a suction hole. FIG. 10 is a perspective view showing a state when a recording medium is conveyed on the platen of FIG. 9. FIG. 11 is a transverse cross-sectional view showing a state when the side edge of the recording medium is warped in FIG.

Explanation of symbols

1 Platen 2 Suction Hole 3 Flexible Member (Suction Aid Member)
4 Recording medium 6 Recording head 11 Support surface 21 Suction duct 22 Fan A Recording medium transport direction H Suction force (negative pressure)
X space

Claims (3)

A recording head for recording on a recording medium by discharging ink;
A platen having a support surface for supporting a recording medium at a position facing the recording head;
A suction means for causing a suction force from a suction hole formed in the platen to act to attract the recording medium to the platen;
A flexible member that is arranged so as to be able to contact the side end of the recording medium supported by the support surface and protrudes from the support surface of the platen toward the recording head when the recording medium does not contact ;
With
A space capable of maintaining the suction force from the suction hole is formed below the side end of the recording medium by contacting the flexible member with the recording medium,
Due to the suction force maintained in the space, the flexible member is displaced to the same height as the support surface against the elastic force of the flexible member, and the side edge of the recording medium is placed on the support surface. An ink jet recording apparatus that is closely attached.   The inkjet recording apparatus according to claim 1, wherein the flexible member is disposed at a position corresponding to a side end portion of the recording medium on the platen. The ink jet recording apparatus according to claim 1 , wherein the suction unit includes a suction duct communicated with the suction hole and a fan attached to the suction duct.

Images