JP2009263140A - Ink jet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet recording device equipped with a recording medium conveying device causing no conveyance bending or slack of a recording medium caused by a difference between conveyance amounts of a conveying roller in an axial direction. <P>SOLUTION: The ink jet recording device has the recording medium conveying device that catches and conveys the recording medium P by the conveying roller 1 which is driven by a drive means, and is provided on a surface with a plurality of projections, and a press roller 2 arranged opposite to the conveying roller 1, and a record means recording an image by discharging ink to the recording medium P. In the recording medium conveying device, the press roller 2 is divided into a plurality of rollers along its axial direction, each of the divided press rollers 2a, 2b, 2c, 2d is provided with a pressing force vary means for varying a pressing force to the recording medium, biting amounts of the projections into the recording medium are varied by varying pressing forces of the divided press rollers 2a, 2b, 2c, 2s by the pressing force vary means so that the conveyance amounts of the recoding medium are varied in the axial direction of the conveying roller 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus using a recording medium conveying device for conveying a recording medium for performing image recording.

  Inkjet recording devices that record images by ejecting ink onto the recording medium do not cause image misalignment or color bleeding, and record high-quality images. It is important to maintain high precision.

  Conventionally, as described in Patent Document 1, as a technique for carrying out such a recording medium with high accuracy, the recording medium is conveyed by a conveying roller (capstan roller) and a pressing roller (pinch roller). In the conveying device, the protrusions having a convex shape with a height of 60 ± 40 μm and 0.5 ± 0.2 mm are arranged on the surface of the conveying roller in an area of more than half of the surface, whereby the conveying roller and the pressing roller are used. A recording medium that increases the gripping force of the recording medium and ensures the conveyance accuracy is known.

Japanese Patent Laid-Open No. 11-240654

  In the conventional recording medium transport apparatus, if the transport amount of the recording medium changes minutely due to changes in the thickness or type of the recording medium, there is a problem that the quality of the recorded image is deteriorated. Need to be finely adjusted. Usually, a stepping motor is used as a drive motor for the transport roller, and the transport amount is adjusted by changing the drive pulse. However, it is impossible to adjust the conveyance amount below the resolution of the drive motor, and it is not possible to finely change the conveyance amount of the recording medium and adjust the conveyance amount by minute changes in the thickness or type of the recording medium. could not.

  Also, for image recording on a recording medium, two sets of conveying rollers and pressing rollers are provided with a recording means for recording an image, and each conveying roller is driven by the same drive motor, and the recording medium is interposed between them. There are many things to do by extending. However, even if each conveyance roller is driven by the same drive motor, a slight difference in conveyance amount occurs between the conveyance rollers due to various factors such as a diameter error of each conveyance roller and a transmission loss of driving force. As a result, there is a problem in that the slack of the recording medium occurs or the recording medium is excessively pulled by one of the conveying rollers, thereby affecting the quality of the recorded image. Since it is impossible to adjust the conveyance amount below the resolution of the drive motor, it was not possible to eliminate the slack or excessive expansion of the recording medium by finely changing the conveyance amount of the recording medium and adjusting the conveyance amount. .

  Further, in the production of the conveyance roller, when the roller diameter is different in the axial direction, the conveyance amount of the recording medium varies depending on the position of the conveyance roller in the axial direction, and there is a problem that the conveyance bending or sagging of the recording medium occurs.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ink jet recording apparatus provided with a recording medium transport device that does not cause bending or sagging of the recording medium due to a difference in the transport amount of the transport roller in the axial direction.

  Other objects of the present invention will become apparent from the following description of the present specification.

  The above problems are solved by the following inventions.

  According to a first aspect of the present invention, there is provided a recording medium transporting device in which a recording medium is sandwiched and transported by a transporting roller driven by a driving means and having a large number of protrusions on the surface and a pressing roller disposed opposite to the transporting roller. An ink jet recording apparatus comprising: an apparatus; and a recording unit that records an image by ejecting ink onto the recording medium conveyed by the recording medium conveying apparatus, wherein the recording medium conveying apparatus includes the pressing roller Is divided into a plurality along the axial direction, and each of the divided pressing rollers is provided with a pressing force changing means for changing the pressing force to the recording medium, and the divided by the pressing force changing means. By changing the pressing force of each pressing roller to change the biting amount of the protrusion with respect to the recording medium, the conveyance amount of the recording medium is reduced. An ink jet recording apparatus characterized by changing in the axial direction of the La.

  According to a second aspect of the present invention, the transport roller is made of a metal roller, and the protrusion is formed to protrude by causing the metal on the surface of the transport roller to protrude, and the surface of the transport roller 2. An ink jet recording apparatus according to claim 1, wherein protrusions having different directions of raising along the circumferential direction are mixed.

  According to the present invention, it is possible to provide an ink jet recording apparatus provided with a recording medium transport apparatus that does not cause bending or sagging of the recording medium due to a difference in the transport amount in the axial direction of the transport roller.

Schematic configuration diagram of recording medium transport device Perspective view of transport roller It is a figure which shows protrusion, (a) is the state which looked at the surface of the conveyance roller from the direction orthogonal to an axis | shaft, (b) shows the state which looked at the surface of the conveyance roller from the axial direction. Conceptual diagram showing bite between protrusion and recording medium Schematic configuration diagram showing an example of pressing force changing means Schematic configuration diagram showing an example of pressing force changing means Schematic configuration diagram showing another embodiment of the recording medium conveying apparatus Schematic configuration diagram showing still another embodiment of the recording medium conveying apparatus

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a recording medium conveying apparatus according to the present invention. The recording medium conveying apparatus includes a conveying roller 1 and a pressing roller 2 that is disposed to face the conveying roller 1 and is made of a rubber roller that is pressed against the surface of the conveying roller 1 by a predetermined pressing force. The recording medium P is sandwiched between the roller 1 and the pressing roller 2, and the conveying roller 1 is rotated in the clockwise direction in the figure by driving of a driving motor 3 such as a stepping motor which is a driving means, whereby the pressing roller 2 is driven. However, the recording medium P is conveyed rightward in the figure.

  In the present invention, the recording medium P is not limited to paper, but is pressed by the pressing roller 2 such as a synthetic resin sheet such as an OHP sheet, cloth, or the like. And a recording medium conveyed by the conveying roller 1 by biting of the protrusions 12.

  The transport roller 1 is made of a metal roller, and a large number of protrusions 12 are formed on the surface thereof. 2 is a perspective view of the conveying roller 1, FIG. 3 is a view showing the protrusion 12, FIG. 3A is a state in which the surface 11 of the conveying roller 1 is viewed from a direction orthogonal to the axis, and FIG. The state which looked at the surface 11 of the roller 1 from the axial direction is shown. Reference numeral 12a in FIG. 2 indicates a protrusion formation region. Here, four protrusion formation regions 12a are formed at intervals along the axial direction of the transport roller 1, but the number is not particularly limited. Absent. Each protrusion forming region 12 a extends over the entire circumference of the transport roller 1.

  As shown in FIG. 3, the protrusions 12 formed in each protrusion forming region 12 a are formed so as to protrude from the surface 11 of the conveying roller 1.

  These protrusions 12 can be formed by a manufacturing method similar to that of a file or grater protrusion. That is, it is possible to make the protrusion 12 project from the surface 11 by strongly pressing a mold having fine and sharp irregularities against the surface 11 of the transport roller 1 and causing the metal on the surface 11 to be rolled up.

  When the conveyance roller 1 is mixed with protrusions 12 that are different in the direction of the conveyance roller 1 from the surface 11 along the circumferential direction, the conveyance roller 1 is recorded by the protrusions 12 in both the forward and reverse directions. This is preferable because a transport force by a strong gripping force of the medium P can be obtained.

  As the arrangement form of the protrusions 12 in each of the protrusion forming regions 12a, the protrusions 12 are arranged in a grid pattern on the surface 11 of the transport roller 1, are aligned in a line in the axial direction and are staggered in the circumferential direction, Various arrangement forms such as those arranged in a zigzag pattern and arranged in a line in the circumferential direction can be used, and there is no particular limitation in the present invention.

  Although the specific shape of each protrusion 12 is not particularly limited, as shown in the drawing, when the taper is gradually tapered from the base on the surface 11 side to the tip of the transport roller 1, the back surface of the recording medium P (the contact surface with the transport roller 1). ) Is preferable because it can be easily pierced.

  In this recording medium conveying apparatus, the recording surface of the recording medium P is sandwiched between the conveying roller 1 and the pressing roller 2 so as to be on the pressing roller 2 side, and the recording medium P is placed on the surface of the conveying roller 1 by the pressing roller 2. When pressed against the recording medium P, the protrusions 12 formed on the surface of the conveying roller 1 pierce and bite into the back surface of the recording medium P. By changing the amount of biting at this time, the virtual feed diameter can be changed by the transport roller 1.

  For example, as conceptually shown in FIG. 4, the recording medium P <b> 1 bitten by pressing the pressing roller 2 with a certain pressing force against the protrusion 12 formed to protrude from the surface 11 of the transport roller 1, and the above pressing. Comparing with the recording medium P2 that has digged in by pressing the pressing roller 2 with a pressing force larger than the pressure, the distances d1 and d2 from the surface 11 are different, so that when the conveying roller 1 is rotated at the same speed, The recording medium P1 has a larger conveyance amount (recording medium feed length) than the recording medium P2. Since the conveyance amount of the recording medium P due to the difference in the biting position of the protrusion 12 appears as a very small difference in the conveyance amount due to the very small protrusion 12, the driving is performed by changing the biting amount of the protrusion 12 with respect to the recording medium P. Without having to change the number of drive pulses of the motor 3, it is possible to adjust a very small conveyance amount below the resolution of the drive motor 3.

  The biting amount H of each protrusion 12 with respect to the recording medium P naturally varies depending on the pressing force, but has a high conveyance accuracy without sagging or loosening to obtain a high-quality image recording, and the recording medium P is substantially damaged. The degree of not giving is preferably less than half (0.5 t or less) with respect to the thickness t of the recording medium P to be conveyed. More preferably, 0.1t <H <0.25t.

  The table below shows the relationship of the recording medium conveyance amount with respect to three different pressing forces, similarly measured with respect to three different roller projection amounts.

(Main recording device conditions)
Conveyance roller (projection roller) material: SUS
Recording medium thickness: 0.25 mm photographic paper is used.
Recording medium width: 102mm

  As the projection amount of the projection roller, 40 μm, 60 μm, and 80 μm are prepared, respectively, and the conveyance amount when the pressing force is changed to 1.64N, 3.27N, 6.54N for each projection roller (mm) ) Is shown below.

  Each of these pressing forces was able to accurately convey photographic paper as a recording medium, and the biting amount at that time was generally 0.1 <H <0.25 t, which is the above-mentioned preferable biting amount. We were satisfied with the range.

  This is because even if the thickness and type of the recording medium change and the conveyance amount may change slightly, the pressing force is changed as described above to control to a preferable biting amount. This means that a very small conveyance amount below the resolution can be adjusted.

  In order to adjust the amount of biting of the protrusion 12 with respect to the recording medium P, the pressing roller 2 is provided with a pressing force changing means for changing the pressing force to the recording medium P. The pressing force changing means is not particularly limited as long as it can change the pressing force of the pressing roller 2 minutely, but an example thereof is shown in FIGS. 5 and 6 are diagrams showing a schematic configuration of the pressing force changing means 4.

  The pressing roller 2 is pivotally supported by one end of a support member 42 that can rotate around a fulcrum shaft 41 parallel to the rotation shaft 21 of the pressing roller 2, and is opposite to the pressing roller 2 across the fulcrum shaft 21. One end of the urging spring 43 is attached. Here, the urging spring 43 is constituted by a tension spring, and the other end is fixed to the fixing portion 5. Accordingly, the urging force of the urging spring 43 urges the pressing roller 2 in a direction in which the pressing roller 2 is pressed against the conveying roller 1. In this aspect, the maximum pressing force of the pressing roller 2 is set by the biasing force of the biasing spring 43.

  An eccentric cam 45 provided so as to be rotatable about a shaft 44 is disposed above the support member 42 and is rotated by a drive motor (not shown). In the state shown in FIG. 5, the cam surface of the eccentric cam 45 is not in contact with the support member 42, and the support member 42 presses the recording medium P against the conveyance roller 1 by the biasing force of the biasing spring 43. Yes. In this state, the pressing roller 2 presses the recording medium P against the conveying roller 1 with the maximum pressing force by the biasing spring 43, and the protrusion 12 of the conveying roller 1 bites into the back surface of the recording medium P most deeply. It becomes a state.

  When the eccentric cam 45 is rotated around the shaft 44 from this state, the cam surface of the eccentric cam 45 comes into contact with the operation end portion 42 a on the biasing spring 43 side of the support member 42 relative to the fulcrum shaft 41. Further, as the eccentric cam 45 rotates, the operation end portion 42a side of the support member 43 is rotated about the fulcrum shaft 41 downward in the figure against the urging force of the urging spring 43. As a result, the pressing roller 2 is moved away from the conveying roller 1 and the pressing force against the recording medium P is weakened.

  In the state shown in FIG. 6, when the operation end 42 a of the support member 42 is pressed downward by the eccentric cam 45, the pressing force against the recording medium P is weakened most, and the back surface of the recording medium P is reduced. The state in which the protrusion 12 of the conveying roller 1 has entered the shallowest portion is shown. By changing the rotation angle of the eccentric cam 45, the pressure roller 2 is changed between the state shown in FIG. 5 and the state shown in FIG. The pressing force is adjusted.

  Note that various embodiments are possible as to how to operate the pressing force changing means. For example, the following embodiments can be adopted.

a) A device (for example, an ink jet recording device) a user selects the type or thickness of the material of the recording medium on the operation panel of the display unit, and the pressing force is changed to a pressing force suitable for the selected type or thickness. A mode in which the changing means is operated.
b) A mode in which the pressing force changing means is operated so that the type and thickness of the recording medium to be conveyed are automatically determined from the electrical resistance value and changed to a pressing force suitable for the determined type or thickness.
c) A configuration in which, in the manufacturing stage of the apparatus, it is set in advance so as to be realized with a pressing force suitable for the type or thickness of the recording medium to be conveyed.

  FIG. 7 is a schematic configuration diagram showing another embodiment of the recording medium conveying apparatus. Here, a schematic configuration of a recording medium conveying device provided in the ink jet recording apparatus is shown.

  In the figure, reference numeral 6 denotes a recording head which is a recording means for recording an image by ejecting ink in droplets from a large number of nozzles arranged opposite to the recording medium P, and 7 denotes a recording head 6 sandwiching the recording medium P. It is the platen arrange | positioned so that it may oppose.

  The recording head 6 is mounted on a carriage (not shown), and the carriage is main-scanned in a direction (perpendicular to the surface shown in the figure) perpendicular to the conveyance direction of the recording medium P by a driving motor (not shown), and ink is ejected in the main scanning process. Thus, one line of image recording on the recording medium P is performed. The recording medium conveying device is configured to intermittently convey the recording medium P by a predetermined amount for each main scanning of the recording head 6 in the sub-scanning direction (right direction in the drawing). A desired image is recorded on the recording medium P by intermittent conveyance of the recording medium P by the medium conveying device.

  In the recording medium conveying apparatus shown here, two sets of conveying rollers and pressing rollers are provided with the recording head 6 interposed therebetween. That is, a pair of the transport roller 1A and the pressure roller 2A is disposed on the upstream side (left side in the figure) of the recording medium P with the recording head 6 interposed therebetween, and on the downstream side (right side in the figure) of the recording medium P in the transport direction. A set of the conveying roller 1B and the pressing roller 2B is disposed.

  The transport rollers 1A and 1B and the pressure rollers 2A and 2B in each set have the same configuration, and the transport rollers 1A and 1B are both driven at the same speed by a single drive motor 3. Yes.

  Here, a first aspect of the recording medium conveying apparatus in which two pairs of the conveying roller and the pressing roller are provided with the recording head 6 interposed therebetween will be described.

  Each pressing roller 2A, 2B is provided with a pressing force changing means 4 as shown in FIGS. 5 and 6, for example, and the pressing force A and the pressing force B can be changed independently. . In this way, by making it possible to independently change the pressing forces A and B of the pressing rollers 2A and 2B, a difference in the amount of biting of the protrusions of the conveying rollers 1A and 1B with respect to the recording medium P can be obtained. By providing a difference in the virtual feed diameter from 1B, it is possible to freely adjust the transport amount between the two transport rollers 1A and 1B.

  Therefore, even if the recording medium P is slack or excessively stretched due to a slight difference in the transport amount between the two transport rollers 1A and 1B, the pressing forces A and B of the press rollers 2A and 2B are reduced. By independently adjusting, while being driven at the same speed by the same drive source, the conveyance amount by each of the conveyance rollers 1A and 1B can be adjusted, and the slack and excessive expansion of the recording medium P can be eliminated. Since the recording head 6 can perform stable recording, a high-quality image can be recorded.

  However, when the pressing forces A and B of the pressing roller 2A and the pressing roller 2B are made different as described above, it is preferable that the pressing forces A and B satisfy A> B. As a result, the amount of biting into the recording medium P by the protrusions of the transport roller 1B on the downstream side in the transport direction becomes relatively smaller than that of the transport roller 1A on the upstream side in the transport direction, thereby causing the transport roller 1B on the downstream side in the transport direction. The virtual feed diameter due to is relatively large, and the conveyance amount of the recording medium P is larger than that of the conveyance roller 1A. Accordingly, while the recording medium P is driven by the same driving source at the same speed, the recording medium P can be appropriately stretched between the transport rollers 1A and 1B, and the smoothness of the recording surface can be maintained.

  Next, a second aspect of the recording medium conveying apparatus in which two pairs of conveying rollers and pressing rollers are provided across the recording head 6 will be described.

  This aspect is that the protruding height of the protrusion of the conveying roller 1B on the downstream side in the conveying direction is set larger than the protruding height of the protrusion of the conveying roller 1A on the upstream side in the conveying direction. In this case, the conveying speeds and outer diameters (excluding protrusions) of the conveying rollers 1A and 1B are the same.

  As a result, if the pressing forces A and B of the pressing rollers 2A and 2B are the same, the virtual feed diameter by the transport roller 1B on the downstream side in the transport direction becomes relatively large, and the transport amount of the recording medium P becomes the transport roller. It becomes larger than 1A. Accordingly, while the recording medium P is driven by the same driving source at the same speed, the recording medium P can be appropriately stretched between the transport rollers 1A and 1B, and the smoothness of the recording surface can be maintained.

  In this aspect, the pressing force changing means is not particularly required for each of the pressing rollers 2A and 2B in order to achieve the above effect. However, as in the first aspect, each of the pressing rollers 2A and 2B is provided. By providing the pressing force changing means, it is of course possible to solve the problem of sagging of the recording medium P and excessive stretching due to a slight difference in the transport amount generated between the transport rollers 1A and 1B. It is.

  Next, a description will be given of a third aspect of the recording medium conveying apparatus in which two pairs of conveying rollers and pressing rollers are provided with the recording head 6 interposed therebetween.

  This aspect is that the number of protrusions per unit area on the surface of the transport roller 1B on the downstream side in the transport direction is larger than the number of protrusions per unit area on the surface of the transport roller 1A on the upstream side in the transport direction. In this case, the conveying speeds and outer diameters (excluding protrusions) of the conveying rollers 1A and 1B are the same.

  When the number of protrusions per unit area is large, the number of contact points between the protrusions and the recording medium P increases, so that the protrusions do not easily bite into the recording medium P. On the other hand, when the number of projections per unit area is small, the number of contact points between the projections and the recording medium P is reduced, so that the projections easily bite into the recording medium P. Therefore, the amount of biting into the recording medium P can be changed by the number of protrusions per unit area.

  As a result, if the pressing forces A and B of the pressing rollers 2A and 2B are the same, the virtual feed diameter by the transport roller B on the downstream side in the transport direction with a large number of protrusions per unit area increases, and the recording medium P The carry amount is larger than the carry roller 1A. Accordingly, while the recording medium P is driven by the same driving source at the same speed, the recording medium P can be appropriately stretched between the transport rollers 1A and 1B, and the smoothness of the recording surface can be maintained.

  Even in this aspect, in order to achieve the above effects, the pressing force changing means is not particularly required for each of the pressing rollers 2A and 2B. However, as in the first aspect, each of the pressing rollers 2A and 2B is provided. By providing the pressing force changing means, it is of course possible to solve the problem of sagging of the recording medium P and excessive stretching due to a slight difference in the transport amount generated between the transport rollers 1A and 1B. It is.

  FIG. 8 shows a schematic configuration of still another embodiment of the recording medium conveying apparatus. Here, the state seen from the direction along the conveyance direction of the recording medium P is shown. The same reference numerals as those in FIGS. 1 and 2 denote the same components, and the description thereof will be omitted unless there is a particular difference.

  Here, the pressing roller 2 disposed so as to face the single conveying roller 1 is divided into a plurality along the axial direction (the left-right direction in the drawing). Although FIG. 8 shows an example in which the roller is divided into four small pressing rollers 2a to 2d, the number of divisions is not limited and is appropriately set according to the size of the recording medium P to be conveyed.

  Further, the lengths in the axial direction of the small pressure rollers 2a to 2d are not limited to the same length, and may be different from each other or only some of the small pressure rollers may be different.

  Each of the divided small pressing rollers 2 a to 2 d is provided with a pressing force changing means for changing the pressing force with respect to the recording medium P sandwiched between the conveying rollers 1. The pressing force changing means is not particularly limited as long as the pressing force of each of the small pressing rollers 2a to 2d can be changed minutely independently. For example, the pressing force changing means 4 shown in FIGS. Are respectively provided so that each of the small pressing rollers 2a to 2d presses the recording medium P with the common conveying roller 1 with the pressing force a, the pressing force b, the pressing force c, and the pressing force d, respectively. Configured as follows.

  In such a recording medium conveying apparatus, the pressing force of each pressing roller 2a to 2d is changed by the pressing force changing means provided on each small pressing roller 2a to 2d, and the protrusion of the conveying roller 1 bites into the recording medium P. The conveyance amount of the recording medium P is changed in the axial direction of the conveyance roller 1 by changing the amount for each small pressing roller 2a to 2d.

  According to such a recording medium conveyance device, the conveyance amount of the recording medium P varies depending on the conveyance amount in the axial direction of the conveyance roller 1 due to an error in the axial diameter of the roller in the conveyance roller 1. Even if bending or sagging occurs, the pressing force a to d of each of the small pressing rollers 2a to 2d is independently adjusted to change the pressing force in the axial direction of the conveying roller 1, and the protrusions at the respective portions are changed. By changing the amount of biting into the recording medium P, the conveyance amount of the recording medium P can be made uniform in the axial direction of the conveyance roller 1, and problems of conveyance bending and sagging can be solved.

  For example, when the conveyance amount of the recording medium P occurs due to the conveyance amount of the recording medium P being smaller than the other portions at the portion of the small pressing roller 2a, the pressing force a of the small pressing roller 2a is changed to another small pressing force. By making it smaller than the pressing forces b to d of the rollers 2b to 2d, the amount of biting of the protrusions of the part into the recording medium P is reduced. As a result, the virtual feed diameter of the transport roller 1 at the small pressing roller 2a is increased and adjusted so that the transport amount is increased, and the transport amount of the recording medium P can be made uniform in the axial direction of the transport roller 1. it can.

  On the other hand, by increasing the pressing force b to d of the small pressing rollers 2b to 2c to be larger than the pressing force a of the small pressing roller 2a, the amount of protrusion of the protrusion at the corresponding part to the recording medium P is increased. You may do it. As a result, the virtual feed diameter of the conveyance roller 1 at the small pressure rollers 2b to 2d is reduced and adjusted so that the conveyance amount is small, and the conveyance amount of the recording medium P is made uniform in the axial direction of the conveyance roller 1. be able to.

  According to such a recording medium conveyance device, the conveyance amount of the recording medium P can be finely adjusted in the axial direction of the conveyance roller 1, and therefore, a printer that records an image on a particularly wide recording medium P, so-called Valid for Large Format Printer.

  Further, such a recording medium conveying apparatus can be widely applied to devices including a conveying system configured to convey a recording medium by sandwiching the recording medium between a conveying roller and a pressing roller.

  Note that the recording medium conveying apparatus shown in FIG. 8 is not limited to the apparatus that conveys the recording medium P alone, and as shown in FIG. And a recording medium conveying apparatus provided with two sets of pressing rollers. In this case, by configuring each pair of the conveyance roller upstream and downstream in the conveyance direction and the pressure roller in the same manner as in FIG. 8, the conveyance amount of the recording medium P is made uniform in the axial direction of the conveyance roller as described above. Can be made.

  The recording medium conveying apparatus described above can be applied to all ink jet recording apparatuses configured to convey a recording medium by sandwiching the recording medium between a conveying roller and a pressing roller. Examples of such a recording apparatus include an ink jet type copying machine and a facsimile in addition to the ink jet printer.

DESCRIPTION OF SYMBOLS 1, 1A, 1B: Conveyance roller 11: Surface 12: Protrusion 12a: Protrusion formation area 2, 2A, 2B: Press roller 2a-2b: Small press roller 21: Support shaft 3: Drive motor 4: Pressing force change means 41: Support shaft 42: Support member 42a: Operation end 43: Biasing spring 43
44: shaft 45: eccentric cam 5: fixed point 6: recording head 7: platen P: recording medium

Claims (2)

A recording medium transporting device that is driven by a driving means and has a surface provided with a plurality of protrusions, and a recording medium that is transported by sandwiching a recording medium by a pressing roller disposed opposite to the transporting roller, and the recording medium transporting device An inkjet recording apparatus having recording means for recording an image by discharging ink to the recording medium conveyed by
In the recording medium conveying apparatus, the pressing roller is divided into a plurality along the axial direction, and each of the divided pressing rollers is provided with pressing force changing means for changing the pressing force to the recording medium,
The amount of conveyance of the recording medium is changed in the axial direction of the conveyance roller by changing the amount of biting of the protrusion into the recording medium by changing the pressure of each of the divided pressure rollers by the pressure force changing means. An ink jet recording apparatus.   The conveying roller is made of a metal roller, and is formed to protrude by causing the protrusion to squeeze the metal on the surface of the conveying roller, and the raising direction along the circumferential direction from the surface of the conveying roller 2. An ink jet recording apparatus according to claim 1, wherein protrusions having different diameters are mixed.

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