JP2006160454A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device, capable of avoiding jam or contamination of a recording medium due to the deterioration of carrying performance by oil in an image forming device that prevents spur marks by application of oil. <P>SOLUTION: In this image forming device, a recording medium is carried toward an image forming means, so that image is formed on the recording medium by the image forming means. It is provided with a holding means to regulate the recording medium in a proper attitude to the image forming means on the downstream side of the image forming means, a feed and application means to feed and apply prescribed quantity of fluid to the holding means, and a carrying means to cooperate with the holding means to hold the recording medium between them so as to regulate the recording medium in the proper attitude to the image forming means, and carry the recording medium in the downstream direction. The carrying means and the holding means are composed not to get in contact with each other. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus that records an image on an image recording medium, and more particularly to an ink jet type image forming apparatus.

  As a conventional image recording apparatus, an image recording medium is intermittently conveyed in a sheet-like image recording unit, and an image is recorded by ejecting ink droplets with a predetermined width in a direction perpendicular to the conveying direction every time the conveying operation is stopped. There is an ink jet recording apparatus.

  FIG. 6 is a schematic cross-sectional view of a printing unit of an image forming apparatus that is conventionally seen. In FIG. 6, the recording medium 201 is fed from the direction of the arrow K and is sandwiched between the sub-scanning roller 202 and the pinch roller 203 pressed against the sub-scanning roller 202, and the platen in the downstream direction is rotated by the rotation of the sub-scanning roller 202. It is conveyed to the 206 side. The platen 206 is disposed so as to planarly support the recording medium 201 conveyed by the sub-scanning roller 202 with its upper surface 206a.

    The main scanning rail 224 is arranged so that its axial direction is perpendicular to the conveying direction of the recording medium 201 and is above the platen 206 and parallel to the upper surface 206a. The carriage 222 is inserted into the main scanning rail 224 and is connected to a linear movement drive mechanism (not shown) so as to be movable in the direction perpendicular to the paper transport direction, that is, in the main scanning direction.

  The carriage 222 has an ink jet recording head 223 therein, and is configured such that its ink discharge surface faces the upper surface 206a of the platen 206. While the carriage 222 moves in the main scanning direction, the ink discharge surface and the recording are recorded. The distance from the medium 201 is maintained with high accuracy as long as the recording medium 201 is corrected in posture by the platen 206.

  The carriage 222 receives an electrical signal from a main body control unit (not shown) via a cable (not shown), transmits the electric signal to the ink jet recording head 223, and discharges ink. When an ejection signal is received during the main scanning movement of the carriage 222, a band-like image having a width corresponding to the ejection nozzle row of the recording head is formed on the recording medium 201 on the platen 206.

  The paper discharge roller 221 is on the downstream side in the conveyance direction of the recording medium 201 with respect to the platen 206, and the height of the highest portion of the peripheral surface thereof and the height of the upper surface 206a of the platen 206 are set to be substantially the same.

  The spur 211 is configured as a rotating body in which a plurality of projecting portions whose tips protrude sharply at the circumferential portion thereof, and is configured to be slightly pressed against the uppermost portion of the circumferential surface of the paper discharge roller 221. The recording medium 201 that has passed through the platen 206 is pinched by the paper discharge roller 221 and the spur 221 to restrict the recording medium 201 from floating from the upper surface 206a of the platen 206, and is applied by the sub-scanning roller 202 and the pinch roller 202. The recording medium 201 is transported with a transport force weaker than the transport force.

  Conventionally, in an image recording apparatus that uses ink containing a dye as a melting component, both the dye component and the solvent component of the ink penetrate into the recording medium 201 relatively quickly, and the recording medium 201 receives the ink on the platen 206. If there is a predetermined time or more until the intermittent conveyance until reaching the spur 211, most of the ink has penetrated into the inside of the recording medium 201, so that the surface of the recording medium 201 is almost dried and the recording medium Even when the protrusions of the spur 211 come into contact with the ink receiving surface 201, there was almost no ink peeling or contact marks.

  However, in recent years, while the speed of print output has been increased, the time until the ink reaches the spur after the ink is received on the platen by the improvement of the conveyance speed of the recording medium and the improvement of the main scanning speed of the head is shortened. In some cases, the ink receiving surface comes into contact with the spur before the ink dries on the recording medium. In such a case, the ink may be peeled off from the recording medium by a spur, or the ink attached to one end of the spur may be retransferred to the recording medium after one revolution of the spur.

  In addition, image recording apparatuses using pigment inks mainly composed of pigments have been developed for image fastness, but the pigment hardly penetrates inside the recording medium, and only the surface layer of the recording medium. Until the pigment is fixed, the surface layer of the recording medium is in a sticky state and the surface rubbing resistance is very weak. Furthermore, the time required for the pigment to dry and fix on the surface of the recording medium is a dye. Longer than system ink.

  Even when the above pigment ink is used, the pigment on the recording medium is peeled off from the recording medium by a spur, or the pigment adhering to one end of the spur is retransferred to the recording medium after one revolution of the spur. In addition, the pigment is deposited on the peripheral protrusion of the spur, and due to the stickiness of the deposited pigment, the ink layer on the new image surface is repeatedly peeled off from the recording medium. In the above case, dot marks are continuously formed on the recorded image in the transport direction, and the image quality is extremely deteriorated.

As a technique for dealing with such a problem, there is a technique disclosed in Japanese Unexamined Patent Application Publication No. 2002-60106. This is to suppress the adhesion and accumulation of ink as much as possible by forming the tip of the spur thinner than the particle size of the ink to be ejected. However, even if such a technique is used, it has not been possible to completely prevent ink adhesion and deposition on the spur.
JP 2002-60106 A

  In view of the above situation, the present applicant has made a proposal for improving the ink peelability against a spur that holds the recording medium immediately after printing. For example, in FIG. 7, a technique for applying a liquid having a function of preventing undried ink ejected on the recording medium 101 from adhering to the spurs 111 to 115, for example, silicon oil having a predetermined viscosity, is proposed. . Or the technique etc. which prevent ink adhesion by performing surface treatments, such as coating, on the surface of the spurs 111-115 are proposed.

  FIG. 7 shows three drawings of the main part of the invention by the applicant. FIG. 7A shows a plan view, FIG. 7B shows a right side view, and FIG. 7C shows a front view. In FIG. 7, the recording medium 101 is conveyed along the upper surface 106 a of the platen 106 by being sandwiched between a sub-scanning roller (not shown) and the corresponding pinch roller from the direction indicated by the conveyance direction K indicated by the arrow. Then, ink is ejected from the recording head 123 driven in the main scanning direction (direction orthogonal to the transport direction K), and an image is formed on the recording medium 101.

  The discharge roller 121 is on the downstream side in the conveyance direction of the recording medium 101 with respect to the platen 106, and the height of the highest portion of the peripheral surface thereof and the height of the upper surface 106a of the platen 106 are set to be substantially the same. Each of the spurs 111 to 115 is configured as a rotating body in which a plurality of projecting portions whose tips protrude sharply are arranged on the circumferential portion thereof, and are supported rotatably around an elastic shaft (not shown). It is configured to be slightly pressed against the top of the peripheral surface of the paper discharge roller 121 by the reaction force. With such a configuration, the recording medium 101 is regulated along the upper surface of the platen 106 so as to maintain a predetermined interval suitable for recording by the recording head 123.

  The recording medium 101 that has passed through the platen 106 is pinched by the paper discharge roller 121 and the spurs 111 to 115 to restrict the recording medium 101 from floating from the upper surface 106a of the platen 106, and is applied by the sub-scanning roller and the pinch roller. The recording medium 101 is configured to be transported with a transport force weaker than the transport force.

  The oil application rollers 131 to 135 are elastic materials whose at least peripheral surfaces can hold a relatively rich liquid such as oil, for example, porous elastic bodies, more specifically felt, sponge, etc. More specifically, ruby cells (Registered trademark) or the like, and is rotatably supported while contacting the spurs 111 to 115. The oil application rollers 131 to 135 are impregnated with a liquid such as silicon oil. Silicone oil is selected by paying attention to releasability from an adhesive substance (for example, undried ink here). When the spurs 111 to 115 are rotated as the recording medium 101 is conveyed, the oil application rollers 131 to 135 that are in contact with the spurs 111 to 135 are driven to rotate to transfer the silicon oil that is impregnated and held to the spurs 111 to 115. ing.

  With such a configuration, a predetermined amount of silicon oil is applied in the vicinity of the cutting edge of the spurs 111 to 115, and even if the ink receiving layer in contact with the undried ink receiving layer of the recording medium 101 is conveyed immediately after image formation, Since the ink does not adhere to and accumulate on the blade edges of the spurs 111 to 115, the image-formed recording is performed by peeling the ink with the blade edges of the spurs 111 to 115 on the recording medium 101 or transferring from the blade edges of the spurs 111 to 115. This brings about an effect that the problem of deteriorating the image quality of the medium 101 does not occur.

  However, in the above-described technique by the present applicant, the spurs 111 to 115 are always in contact with the conveyance roller 121 even when the paper is not passed. For this reason, when a liquid is applied to the spurs 111 to 115, the applied liquid, for example, silicon oil is also transferred to the conveying roller 121 side, causing a jam due to a decrease in conveying force at the time of conveyance, or recording when a sheet is passed. The problem that an undesirable phenomenon such as the recording medium 101 becoming dirty due to the liquid further transferred to the surface of the medium 101 on the sheet discharge roller 121 side has been clarified.

  Accordingly, an object of the present invention is to provide an image forming apparatus capable of avoiding jamming due to deterioration in conveyance performance and contamination of a recording medium by a transferred release material.

  Another object of the present invention is to provide an image forming apparatus in which a holding unit (for example, a spur) and a supply application unit (for example, an oil application roller) can be integrally attached and detached.

  The present invention relates to an image forming apparatus including an image forming unit that conveys a recording medium in a direction toward the image forming unit and forms an image on the recording medium, and the recording medium corresponds to the image forming unit on the downstream side of the image forming unit. Forming a recording medium by cooperating with the holding means, holding the recording medium between the holding means for regulating the posture, supplying and applying means for supplying and applying a predetermined amount of liquid to the holding means, and sandwiching the recording medium therebetween And a conveying unit that regulates the posture according to the unit and conveys the recording medium in the downstream direction, and the conveying unit and the holding unit are configured not to contact each other. Thereby, the liquid applied to the holding means is not transferred to the conveying means.

  According to the present invention, it is possible to obtain an image forming apparatus capable of avoiding jamming due to deterioration in conveyance performance and soiling of a recording medium by a transferred release material. Further, an image forming apparatus in which the holding means (for example, spur) and the supply application means (for example, oil application roller) can be integrally attached and detached can be obtained.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, and FIG. 2 is a plan view, a right side view, and a front view of the main part showing the embodiment of the present invention. 1 and 2, the recording medium 101 is fed from the direction of the arrow K and is sandwiched between the sub-scanning roller 102 and the pinch rollers 103, 104, 105 pressed against the sub-scanning roller 102. By rotation, the sheet is conveyed toward the recording head 123 in the image forming unit direction, that is, in the downstream direction.

  The platen 106 is disposed so as to planarly support the recording medium 101 conveyed by the sub-scanning roller 102 with its upper surface 106a. The main scanning rail 124 has an axial direction perpendicular to the conveyance direction of the recording medium 101 and is disposed above the platen 106 and parallel to the upper surface 106a.

  The carriage 122 is inserted into the main scanning rail 124 and is connected to a linear movement drive mechanism (not shown) and is movable in the directions of arrows L and R, that is, the main scanning direction. The carriage 122 has an ink jet recording head 123 serving as an image forming unit therein, and is configured such that its ink ejection surface faces the upper surface 106a of the platen 106, while the carriage 122 moves in the main scanning direction. The interval between the ink ejection surface and the recording medium 101 is accurately maintained as long as the recording medium 101 is corrected in posture by the platen 106.

  In addition, the carriage 122 receives an electrical signal from the main body control unit via a cable (not shown), transmits the signal to the recording head, and ejects ink. When an ejection signal is received during the main scanning movement of the carriage 122, a band-like image having a width corresponding to the ejection nozzle row of the recording head is formed on the recording medium 101 on the platen 106.

  The conveying means (preferably, the paper discharge roller 121) is on the downstream side in the conveying direction of the recording medium 101 with respect to the platen 106, and the height of the highest portion of the peripheral surface thereof and the upper surface 106a of the platen 106 are substantially the same. Is set.

  The holding means (preferably spurs 111 to 115) is configured as a rotating body in which a plurality of protrusions whose tips protrude sharply are arranged on the circumference thereof. The spurs 111 to 115 regulate the posture of the recording medium 101 so as to follow the platen 106 so that the distance between the head supported by a carriage, which will be described later, and the recording medium 101 becomes a predetermined value. Further, the elastic shafts 116 to 1200 are supported so as to be rotatable.

  Here, the discharge roller 121 is provided with stepped portions 121a to 121e at positions corresponding to the spurs 111 to 115 facing each other across the conveyance path, and does not directly contact the spurs 111 to 115, but in a so-called comb tooth shape in the axial direction. It is comprised so that the outer peripheral part of the spurs 111-115 may be avoided.

  Since the recording medium 101 is held between the spurs 111 to 115 that overlap in a so-called comb-tooth shape and the paper discharge roller 121 when the paper is passed, the elastic shafts 116 to 115 of each of the spurs 111 to 115 are held. 120 is bent, and the spurs 111 to 115 are configured to slightly press the print surface side of the recording medium 101 by the reaction force of the bending.

  Note that the configuration of the paper discharge roller 121 is not limited to a step that avoids the outer periphery of the spurs 111 to 115 described above. For example, a plurality of paper discharge rollers 121 may be arranged in the middle of each spur interval. Further, as in the prior art, the spurs 111 to 115 and the paper discharge roller 121 are configured to nip during normal paper passing, and the spurs 111 to 115 or the paper discharge roller 121 correspond to either of them when the paper is not passing. The spurs 111 to 115 and the paper discharge roller 121 may be configured so as to be detachable so that the spurs 111 to 115 are not in direct contact with each other. In short, the recording medium 101 can be nipped and transported when the paper is passed, and the spurs 111 to 115 and the discharge rollers are configured so that the discharge rollers 121 as the conveying means do not directly touch the outer periphery of the spurs 111 to 115 as the holding means. That is, 121 pairs are sufficient.

  FIG. 3 is a front view of the spurs 111 to 115 as viewed from the axial direction. When attention is paid to the adhesion of ink to the spurs 111 to 115, one blade edge angle viewed from the axial direction of each spur affects the degree of ink adhesion to the blade edge. From the experimental results, the blade edge angle has a relatively sharp angle and little adhesion, but if it is too sharp, there is a problem of strength, and as shown in the figure, the blade edge angle is around 30 ° to 35 ° and the ink adhesion is small. Results were obtained.

  FIG. 4 shows a cross-sectional shape in the plate thickness direction of one cutting edge in the spur. In this embodiment, 110 parts obtained by half-etching the plate thickness are formed and made sharper. This is based on an experimental result that the sharper the ink adhesion is minimized.

  The recording medium 101 that has passed through the platen 106 is held between the paper discharge roller 121 and the spurs 111 to 115 to prevent the recording medium 101 from floating from the upper surface 106a of the platen 106, and the sub-scanning roller 102 and the pinch rollers 102 to 102. The recording medium 101 is transported with a transport force weaker than the transport force applied at 104.

  The oil application rollers 131 to 135, which are supply application means, have at least a peripheral surface of an elastic material that can hold a liquid such as oil relatively abundantly, such as a porous elastic body, and more specifically felt, sponge, and the like. More specifically, it is composed of ruby cell (registered trademark) or the like and is rotatably supported while contacting the spurs 111 to 115. The oil application rollers 131 to 135 are impregnated with, for example, silicon oil as a release material. Silicone oil is selected by paying attention to releasability from an adhesive substance (for example, undried ink here). When the spurs 111 to 115 are rotated as the recording medium 101 is conveyed, the oil application rollers 131 to 135 that are in contact with the spurs 111 to 135 are driven to rotate to transfer the silicon oil that is impregnated and held to the spurs 111 to 115. ing.

  With such a configuration, a predetermined amount of silicon oil is applied in the vicinity of the cutting edge of the spurs 111 to 115, and even if the ink receiving layer in contact with the undried ink receiving layer of the recording medium 101 is conveyed immediately after image formation, There is no problem of degrading the image quality of the image-formed recording medium 101 due to ink peeling or transfer with a spur edge.

  The support means (preferably the holder 151) integrally supports the spurs 111 to 115 and the oil application rollers 131 to 135, and is configured as a unit. The holder 151 is configured to be easily detachable from an image forming apparatus main body (not shown). For example, a configuration that can be detached without using a tool such as a snap fit or a knurled screw, or a configuration that can be detached only with a general tool such as a screwdriver is preferable.

  With such a configuration, when the amount of silicon oil supplied has decreased, or when the spurs 111 to 115 and the oil application rollers 131 to 135 are consumed or damaged, the replacement work can be easily performed, and improvement in maintainability can be expected.

  If the viscosity of the silicone oil is too low, it will ooze out to surrounding components, and if the viscosity is high, it will be difficult to transfer to the spurs 111 to 115, so that a result of 300 cs to 10000 cs is obtained. Yes. If the viscosity increases to some extent, it becomes difficult to impregnate the porous elastic body constituting the oil-coated roller at room temperature. Therefore, during the impregnation operation, silicon oil is heated to impregnate it by decreasing the apparent viscosity. A porous elastic body is suitable for the material of the oil application rollers 131 to 135. For example, in the present embodiment, Ruby Cell (registered trademark) is used.

  FIG. 5 shows another embodiment having a configuration in the vicinity of the release agent coating means of the present invention. In FIG. 5, the cleaning members 141 to 145 are spurs 111 to 115 on the downstream side in the rotation direction from the contact portion with the recording medium 101 with respect to the rotation direction of the spurs 111 to 115 when the recording medium 101 moves in the printing direction. Further, oil application rollers 131 to 135 are arranged and configured on the downstream side in the rotation direction. The cleaning members 141 to 145 are rotatably supported around the rotation center shafts 146 to 150, and can be driven to rotate by contacting the spurs 111 to 115. The cleaning members 141 to 145 are composed of a nonwoven fabric, a porous elastic body, a felt or the like.

  In consideration of durability, the cleaning members 141 to 145 cannot deny the possibility that the ink adheres to the blade edge of the spur coated with oil. In addition, the edge of each spur can be cleaned, and durability can be improved from the viewpoint of maintaining image quality. With the above configuration, it is possible to apply or clean oil as a release agent to the spurs 111 to 115 with a simple configuration.

1 is a perspective view of a main part of an image forming apparatus according to an embodiment of the present invention. 3A and 3B are three views of the main part of the image forming apparatus according to the embodiment of the present invention, in which FIG. 3A is a plan view, FIG. 2B is a right side view, and FIG. It is a front view which shows an example of the shape of the spur of the image forming apparatus concerning embodiment of this invention. It is sectional drawing which shows an example of the shape of the spur of the image forming apparatus concerning embodiment of this invention. It is a principal part front view of the supply application | coating means of the image forming apparatus concerning other embodiment of this invention. It is sectional drawing which shows the outline of the printing part of the conventional image forming apparatus. It is three drawings of the principal part explaining embodiment concerning other invention by this applicant, (a) is a top view, (b) is a right view, (c) is a front view in the figure. It is.

Explanation of symbols

101 recording medium,
121 Paper discharge rollers 121a to 121e Step portions 123 of the paper discharge rollers Recording heads 111 to 115 Spurs 131 to 135 Oil application roller 151 Holder

Claims (2)

In an image forming apparatus including an image forming unit that conveys a recording medium toward an image forming unit and forms an image on the recording medium.
Holding means for regulating the recording medium in a posture corresponding to the image forming means on the downstream side of the image forming means;
Supply and application means for supplying and applying a predetermined amount of liquid to the holding means;
A conveying unit that cooperates with the holding unit to regulate the recording medium in a posture corresponding to the image forming unit by sandwiching the recording medium therebetween and conveys the recording medium in a downstream direction; Have
An image forming apparatus configured to prevent the conveying unit and the holding unit from contacting each other. The holding unit and the supply and application unit are further supported integrally, and the support unit is detachably attached to the image forming apparatus while supporting the holding unit and the supply and application unit. The image forming apparatus according to claim 1.