JP2006240230A - Switching mechanism of distance between head and platen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To change a distance between a head and a platen as needed while maintaining the flatness of the platen even if the width of paper becomes large and further to suppress an increase of cost by making the composition simple. <P>SOLUTION: The mechanism is equipped with an operation lever for dashing a record carrier in the vertical direction and changing the position thereof, a supporting member for supporting the operation lever, a main-scanning direction dashing member for dashing a recording member in the main scanning direction and a sub-scanning direction dashing member for dashing a recording member in the sub-scanning direction. The supporting member, the main-scanning direction dashing member and the sub-scanning direction dashing member are held in a case frame. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet image forming apparatus that forms an image by reciprocating a print head that discharges ink in a direction perpendicular to a conveyance direction of a recording medium. It is related with the thing provided with the mechanism which changes the distance of.

  As a conventional mechanism for changing the distance between the head and the platen, there is one that changes the height of the platen without changing the height of the head (for example, see Patent Document 1).

  Hereinafter, a conventional mechanism for changing the distance between the head and the platen will be described with reference to FIG.

  The recording medium height switching mechanism unit uses the cut sheet or the roll-shaped recording medium conveyed by each sheet feeding unit such as the manual sheet feeding unit, the manual sheet feeding unit, and the roll-shaped recording medium sheet feeding unit as an image forming unit. A conveyance roller 110 is provided for conveyance. Further, the recording medium height switching mechanism unit includes a driven roller (not shown), a conveyance motor (not shown) for rotating the conveyance roller 110, a drive gear (not shown) fastened to the conveyance motor 620, A conveyance roller gear (not shown) fastened to the end of the conveyance roller 110 is provided.

  The conveyance roller 110 is rotatably supported by conveyance roller bearings (not shown) fixed to both side plates (not shown) and 700 (not shown). A tangent line connecting the outer periphery of the transport roller 110 and the outer periphery of the paper discharge roller 510 is arranged in parallel to the ink ejection surface of each print head 151. A platen 130 is provided between the conveying roller 110 and the paper discharge roller 510, and the upper part of the platen 130 is an image forming area. The platen 130 is held slightly higher on the print head 151 side than a tangent line connecting the outer periphery of the transport roller 110 and the outer periphery of the paper discharge roller 510. The platen 130 keeps the distance between the print head 151 and the cut paper (and the roll-shaped recording medium) constant.

  A platen holding member 670 that holds the platen 130 is provided below both longitudinal ends of the platen 130. In addition, an inclined surface 670 a is formed on a portion of the platen 130 that faces the conveyance roller 110. The inclined surface 670 a is in contact with the outer peripheral surface of the transport roller bearing 650. A platen height switching shaft 680 rotatably disposed on both side plates (not shown) is disposed below the paper discharge roller 510. In the vicinity of the platen height switching shaft 680, a 670b having the same inclined surface as the inclined surface 670a of the platen holding member 670 is formed. The platen 130 is held by these two inclined surfaces 670a and 670b.

  A platen reinforcement stay 690 that reinforces the platen 130 is fixed to a portion of the platen 130 other than both ends where the platen holding member 670 is fixed. One end of a tension spring 691 is fixed to both longitudinal ends of the platen reinforcement stay 690, and the other end of the tension spring 691 is fixed to a main body stay (not shown) fixed to both side plates (not shown). Yes. As a result, the platen holding member 670 fixed to the platen 130 is always urged in the downward direction along the two inclined surfaces 670a and 670b.

  Further, the position of the platen holding member 670 is determined by the contact position between the cam outer peripheral surface of the platen height variable cam 681 fastened to the platen height switching shaft 680 and the platen reinforcing stay 690. The platen height variable cam 681 is for changing the position of the platen 130 by changing the height thereof, and the platen height is changed by changing the outer peripheral surface distance of the platen height variable cam 681.

  A platen height switching lever 682 for switching the height of the platen 130 is rotatably fixed to one end portion in the longitudinal direction of the rotation shaft 511 to which the paper discharge roller 510 is fixed. A half-moon gear 683 is fixed adjacent to the platen height switching lever 682. On the other hand, a gear 684 that meshes with the gear 683 is fixed to the lower part of the gear 683 of the platen height switching shaft 680. A platen height switching cam 681 for switching the height of the platen 130 is formed on the platen height switching shaft 680 next to the gear 684. By rotating the platen height switching lever 682, the platen height switching cam 681 rotates, and the height of the platen 130 changes by a certain amount.

Further, a shielding plate (grouper) 685 is fastened and fixed to the platen height switching shaft 680, and platen height position sensors 686 a and 686 b for detecting the position of the platen 130 are provided in the vicinity of the grouper 685. Has been placed. With the rotation of the platen height switching shaft 680, the grouper 685 also rotates. Therefore, the rotational position of the platen height switching cam 681 is detected based on the positions of the sensors 686a and 686b shielded by the grouper 685. The switching means according to the present invention includes a platen height switching shaft 680, a platen height switching cam 681, a platen height switching lever 682, gears 683, 684, and the like.
JP 2000-326576 A (page 10 FIG. 6)

  However, with the conventional mechanism for changing the distance between the head and the platen, it is very difficult to move the platen up and down while maintaining the flatness of the platen in a large image forming apparatus having a sheet width exceeding 42 inches. In addition, the configuration is not only complicated, but also increases costs.

  Accordingly, the present invention has been made in view of the above problems, and the object of the present invention is to reduce the distance between the head and the platen as needed while maintaining the flatness of the platen even when the paper width increases. In addition, it is to simplify the configuration and reduce the cost.

For this reason, in the present invention,
A conveying means for conveying the recording medium; a recording means for performing predetermined recording on the recording medium while reciprocating in a direction perpendicular to the conveying direction of the recording medium; and a driving force for reciprocating the recording means. A driving force applying means for applying, and a recovery means for performing recovery so that the previous recording means performs normal recording,
The recording means includes a recording unit, a recording holding unit that holds the recording unit, an operation lever that abuts the recording holding unit in a vertical direction to change a position, and a support member that supports the operation lever. A main scanning direction abutting member for abutting the recording member in the main scanning direction, a sub scanning direction abutting member for abutting the recording member in the sub scanning direction, the support member, and the main scanning direction abutting A housing portion that reciprocates while holding the abutting member and the abutting member in the sub-scanning direction, and
The recording unit is an ink jet recording system in which a recording unit performs recording by ejecting ink according to a signal,
The image forming apparatus is characterized in that the recording unit includes an electrothermal converter for generating thermal energy for ink ejection,
The image forming apparatus uses a biasing means such as a spring to abut the recording holding unit against the main scanning direction abutting member,
The image forming apparatus uses an urging unit such as a spring to abut the recording holding unit against the abutting member in the sub-scanning direction.
The object is to achieve the object.

  According to the image forming apparatus to which the present invention is applied, the recording holding unit can be translated in the vertical direction by rotating the operation lever, so that the head face surface does not tilt even if the height of the head is changed. As a result, since the ink ejection direction does not change, the registration does not go wrong even if the distance between the head and the platen is changed.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a side view of a carriage to which the present invention is applied, FIG. 2 is a front view of the carriage to which the present invention is applied, and FIG. 3 is an overall view of an image forming apparatus including the carriage according to the present invention.

  First, a schematic configuration of the entire apparatus will be described. As shown in FIG. 3, the main body 1 is on a stand 3, and main units are housed in the main body 1. In the main body 1, a transport unit (not shown) for transporting paper, a carriage unit 2 for performing predetermined recording on the paper, a recovery unit (not shown) for recovering the carriage unit 2, and printing An ink tank unit (not shown) for storing ink for carrying out the operation is provided.

  The main body 1 is connected to a personal computer (not shown), and forms a predetermined image on a sheet in accordance with a print command from the personal computer.

  When a printing command is issued from the personal computer, first, the carriage unit 2 performs a predetermined recovery operation by the recovery unit. Next, paper is loaded from the transport unit to prepare for printing. The carriage unit 2 performs predetermined ejection on the sheet while reciprocating once in the main scanning direction. Then, the conveyance unit conveys a predetermined amount of paper in the sub-scanning direction, and the carriage unit 2 performs predetermined ejection on the paper while reciprocating once in the main scanning direction. By repeating this operation, an image is formed.

  Next, an embodiment of the present invention will be described in detail with reference to FIGS. 1, 2, 4, and 5.

  First, the configuration will be described with reference to FIGS. The translator 8 is engaged with a main rail 18 positioned in the main scanning direction of the main body 1 and a sub rail 19 which is also positioned in the main scanning direction, and reciprocates in the main scanning direction along the two rails.

  The head 4 is held by a head holder 5 and can be attached and detached by opening and closing a head cover (not shown).

  Further, the head holder 5 has four protrusions Y14, two protrusions X, and two protrusions Z, and each of the protrusions abuts against the abutting member.

  First, the Y direction will be described. The head holder 5 is urged in the sub-scanning direction (back-to-front when the main body is viewed from the front) by the sub-scanning direction leaf springs 9 at the left and right positions when the main body is viewed from the front, and the head holder 5 has four positions. The protrusion Y14 abuts against the sub-scanning direction abutting plates 7 at the two left and right positions. At this time, the other ends of the left and right sub-scanning direction leaf springs 9 are received by the translator 8.

  Next, the X direction will be described. The head holder 5 is urged in the main operation direction (from the left side to the right side when the main body is viewed from the front) by the main scanning direction leaf spring 13, and two protrusions X 15 on the head holder 5 are formed on the main scanning direction abutting plate 12. bump into. At this time, the other end of the main scanning direction leaf spring 13 is received by the translator 8.

  Finally, the Z direction will be described. The head holder 5 is urged in the vertical direction (from the bottom to the top) by the vertical compression springs 10 at the left and right when the main body is viewed from the front, and the projections Z16 at the two locations on the head holder 5 change the head height. It hits lever 6. At this time, the other end of the vertical compression spring 10 is received by the translator 8.

  Here, the configuration of the head height switching lever 6 will be described with reference to FIGS. The head height switching lever 6 has two abutting portions 17 for the head height switching lever, and a cross section of the abutting portion 17 for the two head height switching levers is shown in FIG. The abutting surfaces 17A, 17B, and 17C of the height switching lever are provided, and the abutting surfaces 17A, 17B, and 17C of the two head height switching levers are in phase without being shifted. And the protrusion Z16 which exists in two places on the head holder 5 is in contact with any one of the abutting surfaces 17A, 17B, 17C of the head height switching lever, and by rotating the head height switching lever 6 in the axial direction, The abutting surface can be changed. Since the abutting surfaces 17A, 17B, and 17C of the head height switching lever have different distances from the center of the shaft, they have a distance of hA, hB, and hC, and hA−hB = 0.6 mm and hB−hC = 0. .6 mm relationship.

  Further, the head height switching lever 5 is supported by two lever supports 11, and each lever support 11 is fixed to the translator 8 with screws.

  Next, the attachment of the sub-scanning direction abutting plate 7, the main scanning direction abutting plate 12, and the lever support 11 to the translator for making the platen 20 of the head 4 parallel to the main rail 18 will be described.

  The two sub-scanning direction abutting plates 7 are located at a position where the face surface of the head 4 is parallel to the surface of the platen 20 as viewed from FIG. 1, and further, the head 4 is in the longitudinal direction of the main rail 18 (main scanning direction). Is fixed to the translator 8 with screws.

  The main scanning direction abutting plate 12 is determined by a jig so that the face surface of the head 4 is positioned parallel to the surface of the platen as seen from FIG. 2, and is fixed to the translator 8 with screws.

  In the lever support 11, the projection Z 16 of the head holder 5 is in contact with the head height switching lever abutting portion 17 of the head height switching lever 6 in accordance with the position where the head 4 is parallel to the platen 20 and the main rail 18. It is fixed to the translator 8 with screws so that the butt comes in without gaps.

Side view of a carriage to which the present invention is applied Front view of a carriage to which the present invention is applied 1 is an overall view of an image forming apparatus including a carriage according to the present invention. Front view of the head height switching lever Cross section of the abutting part of the head height switching lever The figure explaining the conventional composition

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main body 2 Carriage 3 Stand 4 Head 5 Head holder 6 Head height switching lever

Claims (5)

A conveying means for conveying the recording medium; a recording means for performing predetermined recording on the recording medium while reciprocating in a direction perpendicular to the conveying direction of the recording medium; and a driving force for reciprocating the recording means. A driving force applying means for applying, and a recovery means for performing recovery so that the previous recording means performs normal recording,
The recording means includes a recording unit, a recording holding unit that holds the recording unit, an operation lever that abuts the recording holding unit in a vertical direction to change a position, and a support member that supports the operation lever. A main scanning direction abutting member for abutting the recording member in the main scanning direction, a sub scanning direction abutting member for abutting the recording member in the sub scanning direction, the support member, and the main scanning direction abutting A housing portion that reciprocates while holding the abutting member and the abutting member in the sub-scanning direction;
An image forming apparatus comprising:   The image forming apparatus according to claim 1, wherein the recording unit is an ink jet recording method in which a recording unit performs recording by ejecting ink according to a signal.   The image forming apparatus according to claim 2, wherein the recording unit includes an electrothermal converter for generating thermal energy for ink ejection.   The image forming apparatus according to claim 1, wherein the image forming apparatus uses a biasing unit such as a spring in order to abut the recording holding unit against the main scanning direction abutting member.   The image forming apparatus according to claim 1, wherein the image forming apparatus uses an urging unit such as a spring to abut the recording holding unit against the abutting member in the sub-scanning direction.

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