JP2006231737A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of efficiently adjusting a gap between a print head and recording paper to make the distance of the gap to be constant. <P>SOLUTION: This image forming apparatus comprises: a roller guide rail; and an adjustment means which is a housing stay extending in a main scanning direction for supporting a carriage rail and the roller guide rail in parallel to a platen and can move or fix both ends in the main scanning direction and the central section of the housing stay at the fixing position to the platen, respectively in the contacting/separating direction. After the central section is adjusted to be fixed first, one of both the ends in the main scanning direction is adjusted to be fixed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus that forms an image by ejecting ink onto a recording medium such as recording paper, and in particular, a recording head and a recording medium in a large image forming apparatus capable of forming an image on a wide recording medium. The present invention relates to a gap adjusting mechanism and an adjusting method.

  As one of output devices of computers and workstations, there is known an ink jet image forming apparatus that forms an image by ejecting ink onto a recording medium such as recording paper. The recording medium is conveyed in a predetermined conveyance direction (sub-scanning direction) and temporarily stops in the middle of conveyance, and ink is ejected onto the recording medium during this stop.

  The inkjet image forming apparatus includes a carriage that reciprocates in a main scanning direction orthogonal to the sub-scanning direction. A print head for ejecting ink is mounted on the carriage so as to face the recording medium. The print head reciprocates in the main scanning direction together with the carriage, and ejects ink onto the recording medium during this reciprocation.

  The ink jet type image forming apparatus is formed with a carriage rail that extends in the main scanning direction above the recording medium being conveyed. One end of the carriage in the sub-scanning direction is slidably supported by the carriage rail, and the carriage rail also has a function of guiding the carriage in the main scanning direction. Thus, although the carriage is slidably supported by the carriage rail, the carriage can be rotated about the carriage rail in order to maintain the posture of the carriage (position with respect to the recording medium).

  In addition, two rollers are rotatably disposed at the other end (the rear side of the carriage) opposite to the one end (the front side of the carriage) of the carriage. One of the rollers is fixed to hold the posture of the carriage (position with respect to the recording medium), and the other roller is spring-biased in a direction to sandwich the roller guide rail. These rollers move while rotating as the carriage reciprocates.

  As described above, one end of the carriage in the sub-scanning direction (front side of the carriage) is supported by the carriage rail, while the other end in the sub-scanning direction (back side of the carriage) is a roller guide rail via a roller. It is supported by. In this manner, the carriage reciprocates in the main scanning direction with both ends of the carriage in the sub-scanning direction being fixed.

  In order to reciprocate the carriage, a drive motor is disposed in the inkjet image forming apparatus. Further, pulleys are arranged at both ends in the longitudinal direction of the carriage rail, and an endless belt is stretched around these two pulleys. A carriage is fixed to a part of the endless belt. Therefore, when the drive motor is driven and the pulley rotates, the carriage moves in the main scanning direction together with the endless belt.

  By the way, the print head mounted on the carriage has an ink discharge surface in which a plurality of ink discharge ports for discharging ink are formed side by side. Ink is ejected to a portion (image forming portion) located in front of the ink ejection surface of the recording medium to form an image. The interval (distance) between the ink ejection surface and the image forming portion of the recording medium is usually set to be a constant short distance in order to maintain good image quality.

  However, in the case of the mechanism as described above, the carriage rail and the roller guide rail may be bent depending on the manufacturing reason and the carriage load. In a large-format inkjet image forming apparatus with a large carriage moving distance, this deflection becomes even larger because the carriage rail and roller guide rail become longer.

  When the carriage rail and the roller guide rail are bent as described above, the position of the carriage guided by the carriage rail and the roller guide rail varies according to the bending. Along with this change, when the carriage reciprocates, the attitude of the carriage with respect to the image forming portion of the recording medium changes. For this reason, the interval between the ink ejection surface of the print head that reciprocates with the carriage and the image forming portion of the recording medium varies with the reciprocation of the print head and does not become constant. As a result, the position (landing position) where the ink ejected from the ink ejection surface lands on the image forming portion of the recording medium varies, and the density of the image formed on the image forming portion is not uniform, and the print quality Decreases.

  Therefore, in order to reduce the deflection of the carriage rail and the roller guide rail due to the load of the carriage and the deflection of the carriage rail and the roller guide rail due to the weight of the carriage rail and to prevent the above-described deterioration in the print quality, A technique has been proposed in which the section rigidity of the rail and the roller guide rail is increased to increase the bending rigidity.

  In addition, the carriage rail and roller guide rail are fixed to the housing stay. While increasing the bending rigidity of the housing stay, backup guides are installed at several locations in the center where the carriage rail and roller guide rail are easily bent. In return, a technique has also been proposed in which the carriage rail and the roller guide rail are not easily bent by being fixed to the housing stay.

In addition, with the carriage rail and roller guide rail clamped straight and parallel during assembly, the backup guide configuration can be adjusted in the direction of bending, making errors in production and fixing the fixed position constant. (For example, refer to Patent Document 1).
Japanese Patent No. 3274195 (page 3, FIG. 2)

  Among the above-described conventional techniques, in the technique in which the section modulus of the carriage rail and the roller guide rail is increased to increase the bending rigidity, the section coefficient depends on the shape of the carriage rail and the roller guide rail. There is a problem that it is difficult to miniaturize the forming apparatus.

  When the above-described technology for increasing the section modulus of the carriage rail and roller guide rail is applied to a large-format inkjet image forming apparatus having a large carriage moving distance, the length of the carriage rail and roller guide rail is long. The longer the length, the larger the flexure. Therefore, it is necessary to increase the section modulus of the carriage rail and roller guide rail to increase the bending rigidity. In this case, however, the weight of the carriage rail and the roller guide rail also becomes heavy, so it is necessary to increase the bending rigidity by using a larger section modulus. For this reason, there exists a problem that the whole apparatus becomes still larger.

  Of the conventional techniques described above, the backup guide is returned to several places in the center where the carriage rail and the roller guide rail are easily bent and fixed to the housing stay, so that the carriage rail and the roller guide rail are not easily bent. With this technology, in order to fix the carriage rail and roller guide rail straight and in parallel, there is a need for precise machining for the backup guide and the housing stay, which are the reference for fixing straight and parallel. It will be necessary and will involve high costs.

  In addition, with the carriage rail and roller guide rail clamped straight and parallel during assembly, the backup guide configuration can be adjusted in the direction of bending, correcting errors in production and fixing the fixed position. Technology requires a device to hold the carriage rail and roller guide rail straight and parallel, and a large format inkjet image forming apparatus with a large carriage moving distance requires a larger assembly device. There is a problem. Further, in the large-sized inkjet type image forming apparatus, a large number of locations of the backup guide that holds the carriage rail and the roller guide rail are required, and it is inconvenient from the viewpoint of mass productivity to increase the number of adjustment locations.

  In view of the above circumstances, the present invention holds a carriage rail and a roller guide rail straight and in parallel without requiring a large assembling apparatus even in a large image forming apparatus capable of forming an image on a wide recording medium. Another object of the present invention is to provide an image forming apparatus that can be adjusted efficiently so that the gap distance between the print head and the recording paper is constant at any position in the main scanning direction.

  In order to achieve the above object, an image forming apparatus of the present invention is an image forming apparatus that forms an image on a recording medium on a platen using a print head, and is reciprocated in a predetermined main scanning direction by mounting the print head. A carriage, and a carriage rail extending in the main scanning direction for slidably supporting the carriage in the main scanning direction and supporting the carriage so as to freely rotate in a predetermined orthogonal direction orthogonal to the main scanning direction; A roller guide rail extending in the main scanning direction for guiding a carriage in the main scanning direction, and a housing stay extending in the main scanning direction for supporting the carriage rail and the roller guide rail parallel to the platen, The fixed position of the housing stay with respect to the platen can be moved and fixed individually in the main scanning direction at both ends and in the center portion. In a recording medium of an image forming apparatus, in which an adjustment mechanism having an adjustable adjustment means first adjusts and fixes the central portion, and then adjusts one end of both ends in the main scanning direction in the order of adjustment and fixing And how to adjust the gap.

  The mounting surface for supporting the carriage rail and the roller guide rail of the housing stay has a maximum value in the separation direction (convex direction) or an approach direction (concave direction) with respect to the platen with respect to both ends in the main scanning direction. In the direction from the reference in the main scanning direction to the maximum value in the central portion or the minimum value, it may be pressed so as to be formed with a gentle surface.

  The main scanning direction both ends and the center adjustment means are the reference of both ends in the main scanning direction of the mounting surface supporting the carriage rail and the roller guide rail of the housing stay, and the maximum value of the center, or Adjustment means capable of moving and fixing at the position of the minimum value may be used.

  The housing stay may be manufactured in the same cross-sectional shape in the main scanning direction.

  The present invention does not require a large assembling device, and the carriage rail and the roller guide rail are held straight and parallel so that the gap distance between the print head and the recording paper is constant at any position in the main scanning direction. An image forming apparatus that can be adjusted efficiently can be provided.

  With the goal.

(Embodiment 1)
Hereinafter, an embodiment of an inkjet image forming apparatus of the present invention will be described with reference to the drawings.

  A schematic configuration of a color plotter (hereinafter referred to as a plotter) in which an embodiment of an inkjet image forming apparatus of the present invention is incorporated will be described with reference to FIGS. 1, 2, and 3.

  FIG. 1 is a perspective view showing a schematic configuration of the appearance of a plotter as seen from the front.

  2 is a cross-sectional view schematically showing a schematic configuration of the internal structure of the plotter, and FIG. 3 is a perspective view schematically showing a schematic configuration of the internal structure of FIG.

  The plotter 1 is fixed to the top of a stand 2 with casters 2a. The plotter 1 includes an operation unit 3 for operating the plotter 1, and the paper size, online / offline, command, and the like are instructed by various switches and the like installed in the operation unit 3. The recording paper 4 (roll paper) in the roll paper storage unit is conveyed to the inside of the plotter 1 based on an instruction from the operation unit 3, printed with a color image, and discharged from the recording paper discharge port 5 in the direction of arrow A. The

  As shown in FIG. 3, various components and members are accommodated in the plotter 1. The two support plates 6A and 6B facing each other at a predetermined interval are fixed to the upper part of the stand 2 with casters 2a. Between the support plate 6A and the support plate 6B, a cylindrical carriage rail 7 extends so as to straddle in the main scanning direction (arrow B direction) orthogonal to the transport direction (arrow A direction) in which the recording medium is transported. . On the lower surface of the carriage rail 7, the backup guide 8 is returned to several places in the longitudinal direction and fixed to the housing stay 9. Furthermore, the housing stay 9 is fixed to the support plates 6A and 6B at both ends in the longitudinal direction. Further, on the upstream side of the carriage rail 7 in the direction of arrow A, there is a roller guide rail 16 arranged in parallel to the carriage rail 7. Similar to the carriage rail 7, the guide rail base 28 is returned to several places in the longitudinal direction on the lower surface of the roller guide rail 16 and fixed to the housing stay 9.

  A carriage 10 that reciprocates in the main scanning direction is slidably fixed to the carriage rail 7. The carriage 10 freely rotates about the carriage rail 7 as a central axis if there is no restriction from the outside. A print head 11 and the like are detachably mounted on the carriage 10.

  As shown in FIG. 2, a sliding groove 12 into which the carriage rail 7 is fitted is formed at the center of the bottom of the carriage 10 in the arrow A direction. The sliding groove 12 extends in the direction of arrow B and has an opening facing downward. For this reason, the carriage rail 7 is fitted in the sliding groove 12, but its lower surface is exposed.

  In order to reciprocate the carriage 10 in the direction of arrow B, a drive motor 13 is disposed on the housing stay 9. A pulley 14A is rotatably disposed on the drive motor 13 at one of the longitudinal ends of the carriage rail 7, and a pulley 14B (not shown) is rotatably disposed on the other. The two pulleys 14A and 14B include An endless belt 15 is stretched over. The carriage 10 is fixed to a part of the endless belt 15.

  The drive motor 13 is controlled based on a drive control pulse signal transmitted from a carriage conveyance drive control unit (not shown). Therefore, when the drive motor 13 is driven at a predetermined timing and the pulley 14A rotates, the carriage 10 reciprocates in the arrow B direction together with the endless belt 15. During this reciprocation, the carriage 10 is guided by the carriage rail 7 and the roller guide rail 16.

  A print head 11 for ejecting ink of each color such as yellow, magenta, cyan, and black is detachably mounted on the carriage 10. The print head 11 is composed of four print heads corresponding to each color ink of an ink cartridge (not shown) connected by a tube (not shown). A drive pulse signal is sent to the print head 11 from a print head control unit (not shown) that controls the print head 11. The drive pulse signal is formed based on the image data, and the print head 11 is controlled to eject ink at a predetermined timing based on the drive pulse signal.

  As shown in FIG. 2, a roller 17 and a roller 18 are rotatably disposed at the end of the carriage 10 opposite to the sliding groove 12 at the center in the direction of arrow A. The roller 17 is fixed to hold the posture of the carriage (position with respect to the recording medium), and the roller 18 is attached to be rotatable around a fulcrum 18A and is fixed in a direction in which the roller guide rail 16 is sandwiched by a spring 19. The spring is biased by the force of. These rollers move while rotating as the carriage reciprocates. For this reason, when the position (height) of the lower wall varies depending on the position of the roller guide rail 16 in the longitudinal direction, the posture of the carriage 10 also varies.

  Further, in the region where the carriage 10 reciprocates, a standby region portion 20 where the carriage 10 waits is formed in a region outside the support plate 6A, as shown in FIG. A recovery processing unit 21 that recovers the print head 11 so that the ink discharge state from the print head 11 becomes the initial discharge state is provided at a predetermined reference position (home position) in the standby region unit 20. The recovery processing unit 21 faces the ink discharge surface of the print head 11 and has a known structure having a capping mechanism that selectively covers and sucks the ink discharge surface. The recovery processing unit 21 is controlled based on a drive control signal supplied at a predetermined timing from a recovery processing drive control unit (not shown).

  A transport system for transporting the recording paper 4 (roll paper) will be described.

  A conveyance roller 22 for conveying the recording paper 4 is disposed obliquely below the carriage rail 7. A driven roller 23 having a smaller diameter than the transport roller 22 is disposed on the transport roller 22. The recording paper 4 is conveyed in the direction of arrow A (conveyance direction) while being sandwiched between these two rollers 22 and 23.

  A platen 24 on which the recording paper 4 is placed is disposed at a position facing the print head 11. A portion of the recording paper 4 placed on the platen 24 is separated from the ink ejection surface of the print head 11 by a predetermined interval. On the downstream side of the platen 24 in the direction of arrow A, a conveyance path is formed for conveying the recording paper 4 toward a cutter (not shown) that cuts the recording paper 4 to a predetermined length. A suction fan (not shown) is disposed below the image forming area 25. Also, a portion of the platen 24 corresponding to the image forming area 25 is formed with a number of suction holes 24a. While the recording paper 4 is being conveyed, the suction fan is operated to suck air through the suction holes 26. Then, the recording paper 4 is sucked into the platen 24. As a result, the recording paper 4 is prevented from being lifted and brought into close contact with the platen 22, and the recording paper 4 and the ink ejection surface of the print head 11 are kept at a constant interval.

  Both end portions of the transport roller 22 are rotatably fixed to bearings (not shown) attached to the support plate 6A and the support plate 6B, respectively. Similarly, the transport roller 23 is rotatably fixed to a bearing (not shown). A pulley 25 is fixed to one end of the conveyance roller 22, and a pulley 27 is fixed to the conveyance drive motor 26, and the endless belt 15 is stretched over the pulley. The conveyance drive motor 26 is controlled based on a drive control pulse signal from a conveyance roller drive control unit (not shown). Thereby, the drive motor 26 is controlled so that rotation and stop are alternately repeated according to the recording operation of the print head 11. Accordingly, the recording paper 4 is intermittently conveyed according to the recording operation of the print head 11.

  The overall configuration of the inkjet image forming apparatus has been described above. Each of the above-described components / members is controlled by a conveyance roller drive control unit (not shown, the same applies hereinafter), a print head control unit, a carriage conveyance drive control unit, and a recovery processing drive control unit that control these components / members. Be controlled.

  When an image is formed on the recording paper 4, ink is ejected from the print head 11 to the recording paper 4 based on predetermined image data, and an image is formed on the recording paper 4. In the inkjet image forming apparatus 1, a print head 11 for each color such as yellow, magenta, cyan, and black is mounted on the carriage 10 in order to form a color image. Further, in order to improve the image quality, the print head 11 is mounted on the carriage 10 so that the ink ejection surface of the print head 11 is kept at a constant distance from the recording paper 4.

  As described above, in the carriage 10, the roller 17 is biased by a constant spring in a direction sandwiching the roller guide rail 16 with the position (height) below the roller guide rail 16 as a reference, and the carriage rail 7. Rotation around the center axis is restricted. Further, when the carriage 10 reciprocates in the arrow B direction (main scanning direction), the carriage 10 is guided in the arrow B direction by the carriage rail 7 and the roller guide rail 16. This reciprocation is performed based on the above image data, and ink is ejected from the ink ejection surface of the print head 11 onto the recording paper 4 during the reciprocation to form an image.

  As described above, when the distance and positional relationship between the carriage rail 7 and the roller guide rail 16 change in the region (range) in which the carriage 10 can reciprocate, the carriage 10 depends on the position in the main scanning direction (arrow B direction). The ink discharge surface of the print head 11 cannot keep a constant distance from the recording paper 4, and as a result, the landing positions at which the ink discharged from the ink discharge surface lands on the recording paper 4 vary. As described above, when the ink landing positions vary, the image quality deteriorates.

  Therefore, in the inkjet image forming apparatus 1, the carriage rail 7 and the roller guide rail 16 are held straight and parallel, and the position of the print head 11 and the recording paper 4 is kept at a constant interval at any position in the main scanning direction. A technique that can be used will be described with reference to FIGS.

  First, with reference to FIGS. 4 to 6, the support structure of the housing stay 9 that is a structure that supports the carriage rail 7 and the roller guide rail 16 will be described.

  FIG. 4 is a perspective view showing the structure supporting the carriage rail 7 and the roller guide rail 16, and FIG. 5 is a perspective view showing each part of the structure. FIG. 6 is a front view of the structure showing the processing accuracy in the height direction with respect to the main scanning direction.

  The carriage rail 7 extends so that a cylindrical shape straddles the main scanning direction (arrow B direction) orthogonal to the transport direction (arrow A direction). A backup guide 8 is disposed on the lower surface of the carriage rail 7 and is formed by injection molding. The backup guides 8 are arranged in seven places at the same interval in the main scanning direction in order to prevent bending due to the weight of the carriage 10 and the weight of the carriage rail 7. These seven backup guides 8 are sandwiched between the carriage rail 7 and the housing stay 9, and the carriage rail 7 is fixed to the housing stay 9 with screws 8a.

  On the upstream side of the carriage rail 7 in the direction of arrow A, there is a roller guide rail 16 disposed in parallel to the carriage rail 7. The roller guide rail 16 has a flat cross-sectional shape. A guide rail base 28 is disposed on the lower surface of the flat cross section and is formed by injection molding. Similarly to the above description, the guide rail bases 28 are arranged in five locations at the same interval in the main scanning direction in order to prevent the carriage 10 from being bent due to the weight of the carriage 10 and the weight of the roller guide rail 16. These five guide rail bases 28 are sandwiched between the roller guide rail 16 and the housing stay 9, and the roller guide rail 16 is fixed to the housing stay 9 with screws 28a.

  The housing stay 9 is configured by combining a housing stay base plate 9a and a housing stay reinforcing plate 9b, which are manufactured by press working with a thin steel plate extending in the same cross-sectional shape in the main scanning direction. The housing stay base plate 9a serves as a reference for fixing the carriage rail 7 and the roller guide rail 16 straight and in parallel. The housing stay reinforcing plate 9 b is a reinforcing member for preventing the deflection of the carriage rail 7, the roller guide rail 16, and the housing stay 9 due to its own weight.

  A housing stay holding plate (right) 30 and a housing stay holding plate (left) 31 for fixing to the support plates 6A and 6B are disposed at both longitudinal ends of the housing stay base plate 9a. They are fixed by screws 30a and 31a, respectively. Further, a housing stay holding plate (center) 32 is disposed at a substantially central portion between the housing stay holding plate (right) 30 and the housing stay holding plate (left) 31, and is fixed by screws 32a. ing.

  As described above, the housing stay 9 is configured by combining the housing stay base plate 9a and the housing stay reinforcing plate 9b, which are manufactured by press working with a thin steel plate, as shown in FIG. The housing stay is based on points a and b on the A surface of the housing stay base plate 9a to which the housing stay holding plate (right) 30 and the housing stay holding plate (left) 31 are attached. The point c at which the holding plate (center) 32 is attached has a maximum value in a direction away from the platen 24 (convex direction), and between the points a and c, and between the points b and c, the point c. Is pressed so as to be formed on a gentle surface with a maximum value. Also, the state where the point a and the point b are defined as 0 and the point c is formed as a maximum surface with a gentle surface is that the housing stay holding plate (right) 30 and the housing stay holding plate (left) 31 are attached. Only the two ends in the longitudinal direction are supported, and the carriage rail 7, the roller guide rail 16, and the case stay 9 are kept in a state of being bent due to their own weight.

  Next, with reference to FIGS. 7 to 11, an adjustment and fixing method for the support plates 6 </ b> A and 6 </ b> B of the housing stay 9 which is a structure that supports the carriage rail 7 and the roller guide rail 16 will be described. .

  7 is a perspective view of the structure supporting the housing stay 9 as viewed obliquely from the rear, and FIG. 8 is a cross-sectional view taken along line EE of FIG. 9 is a cross-sectional view taken along the line FF in FIG. 7, and FIG. 10 is a cross-sectional view taken along the line GG in FIG. FIG. 11 is an explanatory view showing an adjustment method in which the fixing position of the housing stay 9 is adjusted by the assembling jig so that the positions of the print head 11 and the recording paper 4 can be kept at a constant interval.

  As shown in FIG. 7, a platen stay (not shown) for holding a platen 24 on which the recording paper 4 is placed, between the support plates 6A and 6B supporting the housing stay 9, and The main stay 33 is disposed and fixed so as to be sandwiched, and the rigidity of the entire apparatus is maintained.

  8 is a diagram showing a method of fixing the support plate 6A of the housing stay holding plate (right) 30 that is fixed to one of both ends in the longitudinal direction of the housing stay base plate 9a.

  In the vicinity of the screw 30a on the housing stay base plate 9a to which the housing stay holding plate (right) 30 is fixed, tapping is formed on the housing stay base plate 9a and the adjustment screw 34 is directed downward. It is concluded. Further, the screw tip of the adjustment screw 34 has a protrusion 35 formed on the support plate 6A that fits into the groove portion of the housing stay holding plate (right) 30, and the adjustment screw 34 is rotated and tightened or loosened. Thus, the housing stay base plate 9a and the housing stay holding plate (right) 30 can be moved in the arrow Z direction with respect to the support plate 6A. The housing stay holding plate (right) 30 is formed with a long hole (not shown) for fixing to the support plate 6A, and the housing stay holding plate (right) moved to a predetermined position by the adjusting screw 34. ) 30 can be fixed to the support plate 6A with screws 30b.

  Next, the FF cross section of FIG. 9 is a diagram showing a fixing method for the support plate 6B of the housing stay holding plate (left) 31 fixed to the other end of both ends in the longitudinal direction of the housing stay base plate 9a. It is.

  In the vicinity of the screw 31a on the housing stay base plate 9a to which the housing stay holding plate (left) 31 is fixed, tapping is formed on the housing stay base plate 9a and the adjustment screw 36 is fastened downward. Has been. Further, the screw tip of the adjustment screw 36 has a projection 37 formed on the support plate 6B that fits into the groove portion of the housing stay holding plate (left) 31, and the adjustment screw 36 is rotated and tightened or loosened. Thus, the housing stay base plate 9a and the housing stay holding plate (left) 31 can be moved in the arrow Z direction with respect to the support plate 6B. The housing stay holding plate (left) 31 is formed with a slot (not shown) for fixing to the support plate 6B, and the housing stay holding plate (left) moved to a predetermined position by the adjusting screw 36. ) 31 can be fixed to the support plate 6B with screws 31b.

  Next, the GG cross section of FIG. 10 shows the housing stay holding plate (right) 30 and the housing stay holding plate (fixed at a substantially central portion between the housing stay holding plate (left) 31). It is a figure which shows the fixing method with respect to the main stay 33 of the center (32).

  In the vicinity of the screw 32a on the housing stay base plate 9a to which the housing stay holding plate (center) 32 is fixed, tapping is formed on the housing stay base plate 9a and the adjusting screw 39 is fastened downward. Has been. Further, an adjustment plate 38 fixed to the main stay 33 is disposed at the screw tip of the adjustment screw 39, and a protrusion formed on the adjustment plate 38 that fits into a groove portion of the housing stay holding plate (center) 32. The housing stay base plate 9a and the housing stay holding plate (center) 32 can be moved in the direction of the arrow Z relative to the main stay 33 by rotating and tightening or loosening the adjusting screw 39. It is. The housing stay holding plate (center) 32 is formed with a long hole (not shown) for fixing to the adjustment plate 38 and moved to a predetermined position by the adjustment screw 39 (center). ) 32 can be fixed to the adjusting plate 38 with a screw 32b.

  As described above, the housing stay base plate 9a can be moved in the direction of the arrow Z and fixed individually by the adjustment screw 34, the adjustment screw 36, and the adjustment screw 39 at both ends in the longitudinal direction and at the center. As a result, the housing stay base plate 9a, which is a reference for fixing the carriage rail 7 and the roller guide rail 16 straight and in parallel, can be moved. Therefore, the carriage rail 7 and the roller guide rail 16 also have both longitudinal ends. It is possible to move and fix the part and the central part in the arrow Z direction.

  FIG. 11 is a front view schematically showing a state in which the fixing position of the housing stay 9 is adjusted by the assembly jig. A jig head 42 having the same outer shape as the print head 11 is mounted on the carriage 10. The jig head 42 is a jig capable of measuring the distance between the ink ejection surface of the actual print head 11 and the upper surface 41 (dotted line portion) of the platen 24 on which the recording paper 4 is placed. The carriage 10 to which the jig head 42 is attached moves the carriage 10 to which the jig head 42 is attached to a position 43c where the housing stay holding plate (center) 32 is fixed. The adjustment screw 39 is rotated so that the distance hc becomes an appropriate distance, and the position value at 43c of the housing stay base plate 9a is moved and fixed to the adjustment plate 38. Here, the position 43c is the maximum value in the direction in which the surface of the housing stay base plate 9a is separated from the platen 24 as described above with reference to FIG. Next, of the longitudinal ends of the housing stay base plate 9a, the housing stay holding plate (right) 30 is moved to a position 43a, and the distance ha between the jig head 42 and the upper surface 41 is increased. The adjustment screw 34 is rotated so as to be an appropriate distance, and the position value at 43a of the housing stay base plate 9a is moved and fixed to the support plate 6A.

  With the above adjustment, the distance between the print head 11 and the upper surface 41 of the platen 24 is adjusted to an appropriate position from the center to the longitudinal end (right) of the carriage 10 in the main scanning direction. Next, the carriage 10 on which the jig head 42 is mounted is moved to a position 43b on the side where the housing stay holding plate (left) 31 is fixed, and the jig head 42 and the upper surface 41 are moved in the same manner as the 43a side. The adjustment screw 36 is rotated so that the distance hb becomes an appropriate distance, and the position value at 43b of the housing stay base plate 9a is moved and fixed to the support plate 6B. With the above adjustment, the distance between the print head 11 and the upper surface 41 of the platen 24 is adjusted to an appropriate position from the center to the longitudinal end (left) of the carriage 10 in the main scanning direction. The distance between the print head 11 and the upper surface 41 of the platen 24 is adjusted to an appropriate position in the entire area of the left and right ends and the central portion.

  As described above, according to the image forming apparatus according to the present invention, the jig head having the same outer shape as the print head is mounted, and the carriage is moved to the central portion in the main scanning direction and both ends to individually And the distance between the platen and the platen can be adjusted. Therefore, even a large image forming apparatus capable of forming an image on a wide recording medium can be adjusted only with a jig head having the same outer shape as the print head without requiring a large assembling apparatus. Also, as shown in FIG. 6, the distance between the print head and the platen is constant at any position in the main scanning direction of the carriage by adjusting the central portion, which is the maximum position in the direction away from the platen, by pressing. It can be adjusted to become.

(Embodiment 2)
Next, a second embodiment will be described.

  FIG. 6 is a front view of the structure showing the processing accuracy in the height direction with respect to the main scanning direction. In the first embodiment, points a and b on the A surface of the housing stay base plate 9a are shown. The point c where the housing stay holding plate (center) 32 is attached is pressed to the maximum value in the direction away from the platen 24 (convex direction). Even if the c point on which the plate (center) 32 is attached is pressed so as to be the minimum value in the direction (concave direction) approaching the platen 24, the first value can be adjusted by adjusting the minimum value portion. It is possible to obtain the same effect as in the embodiment and to adjust the distance between the print head and the platen at any position in the main scanning direction of the carriage.

It is a perspective view which shows schematic structure of the external appearance of the plotter seen from the front. It is sectional drawing which shows typically schematic structure of the internal structure of a plotter. FIG. 3 is a perspective view schematically showing a schematic configuration of an internal structure of FIG. 2. It is a perspective view which shows the structure which is supporting the carriage rail and the roller guide rail. It is the perspective view which showed each component of the structure which is supporting the carriage rail and the roller guide rail. It is a front view of a structure showing the processing accuracy in the height direction with respect to the main scanning direction. It is the perspective view seen from the slanting back which shows the structure which supports the housing stay. It is EE sectional drawing of FIG. It is FF sectional drawing of FIG. It is GG sectional drawing of FIG. It is explanatory drawing which shows the adjustment method which can adjust the fixed position of a housing stay with an assembly jig, and can maintain the position of a print head and a recording paper at a fixed space | interval.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plotter 2 Stand 2a Caster 3 Operation part 4 Recording paper 5 Recording paper discharge port 6A Support plate 6B Support plate 7 Carriage rail 8 Backup guide 9 Housing stay 9a Housing stay base plate 9b Housing stay reinforcement plate 10 Carriage 11 Print head DESCRIPTION OF SYMBOLS 12 Sliding groove 13 Drive motor 14A Pulley 14B Pulley 15 Endless belt 16 Roller guide rail 17 Roller 18 Roller 18A A fulcrum 19 Spring 20 Standby area part 21 Recovery processing part 22 Conveyance roller 23 Follower roller 24 Platen 24a Suction hole 25 Image formation area 26 Conveyance drive motor 27 Pulley 28 Guide rail base 30 Housing stay holding plate (right)
30a Screw 31 Housing stay holding plate (left)
31a Screw 32 Housing stay holding plate (center)
32a screw 33 main stay 34 adjustment screw 36 adjustment screw 38 adjustment plate 39 adjustment screw 40 projection 41 upper surface 42 jig head 43a carriage measurement position 43b carriage measurement position 43c carriage measurement position

Claims (4)

In an image forming apparatus that forms an image on a recording medium on a platen using a print head, a carriage mounted with the print head and reciprocating in a predetermined main scanning direction, and the carriage slidable in the main scanning direction A carriage rail extending in the main scanning direction for supporting and rotating freely in a predetermined orthogonal direction orthogonal to the main scanning direction, and extending in the main scanning direction for guiding the carriage in the main scanning direction. A housing stay extending in a main scanning direction for supporting the roller guide rail and the carriage rail and the roller guide rail in parallel to the platen, wherein a fixed position of the housing stay with respect to the platen is set at both ends in the main scanning direction. In an adjustment mechanism comprising adjustment means capable of moving and fixing the part and the central part individually in the contact and separation directions,
An image forming apparatus comprising: first adjusting and fixing a central portion, and then adjusting one of both end portions in the main scanning direction in the order of adjustment and fixing.   The mounting surface for supporting the carriage rail and the roller guide rail of the housing stay has a maximum value in the separation direction (convex direction) or an approach direction (concave direction) with respect to the platen with respect to both ends in the main scanning direction. 2. A press-work process is performed so as to form a smooth surface between the reference value of the end portion in the main scanning direction and the maximum value or the minimum value in the central portion in the main scanning direction. The image forming apparatus described in 1.   The main scanning direction both ends and the center adjustment means are the reference of both ends in the main scanning direction of the mounting surface supporting the carriage rail and the roller guide rail of the housing stay, and the maximum value of the center, or The image forming apparatus according to claim 2, wherein the image forming apparatus is an adjusting unit that can be moved and fixed at a minimum position.   The image forming apparatus according to any one of claims 1 to 3, wherein the housing stays are manufactured to have the same cross-sectional shape in the main scanning direction.

Images