JP2006341572A - Liquid jet apparatus and detecting unit of rotation of guide shaft therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the function of detecting rotation of a guide shaft 140 from deteriorating due to contamination with ink mist. <P>SOLUTION: The liquid jet apparatus is equipped with the guide shaft 140, a carriage 150 which is guided by a guide part 142 to reciprocate, a recording head 156 which ejects ink while being conveyed by the carriage 150, a disc-like rotary encoder equipped with a scale and fitted coaxially with the guide shaft 140, a sensor 146 which detects the rotation of the guide shaft 140 on the basis of a change of a quantity of reflecting light from the disc as a result of passing of the scale, and a control part 200 which detects a displacement of the guide part 142 on the basis of an output of the sensor 146. The guide shaft 140 includes the guide part 142, cams 410 formed at both ends of the guide part 142 and different in distance from a center axis, and a supporting part which displaces the guide part 142 in a direction orthogonal to the center axis by rotation. The rotary encoder has the scale formed as a magnetic flux distribution or magnetic permeability distribution of a loop shape centered around a rotational axis of the guide shaft 140 on a circular surface of the side not faced to the recording head 156. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid ejecting apparatus, a rotation detecting unit for a guide shaft therefor, and a recording apparatus. More specifically, the present invention relates to a rotation detecting unit that detects the rotation of a guide shaft that guides a carriage that transports a liquid ejecting head in a liquid ejecting apparatus including a recording apparatus, and a liquid ejecting apparatus or a recording apparatus including the rotation detecting unit.

  The range in which the liquid ejecting head can attach the liquid to the recording material at a time is limited. Therefore, in many liquid ejecting apparatuses, a combination of an operation of moving a recording object in a specific transport direction and an operation of ejecting liquid while reciprocating a liquid ejecting head in a main scanning direction intersecting the transport direction, Liquid is adhered to a wide area on the recording material. Some liquid ejecting apparatuses have a structure in which a liquid ejecting head is transported to a carriage that reciprocates along a rod-shaped guide shaft.

  Further, in the liquid ejecting apparatus, the liquid ejected from the liquid ejecting head diffuses as it moves away. For this reason, keeping the platen gap, which is the distance between the liquid ejecting head and the recording material, significantly affects the recording quality. In addition, the specification of the recording material handled in one liquid ejecting apparatus is not limited to one type, and when a recording material having a different thickness is loaded, it is appropriate if the recording head is not ink-jetted accordingly. Platen gap is not maintained.

  Therefore, in the liquid ejecting apparatus having the guide shaft described above, a mechanism for displacing the guide shaft is provided so that the platen gap can be adjusted. In the mechanism for displacing the guide shaft, a means for detecting the displacement of the guide shaft is provided to control the displacement operation itself. This kind of position detecting means can be configured by combining, for example, an encoder mounted on a guide shaft and an optical sensor for detecting the displacement of the encoder.

  On the other hand, liquid droplets ejected from a liquid ejecting head onto a recording material are extremely miniaturized in recent liquid ejecting apparatuses due to a demand for improving recording resolution. Since such a fine droplet has a very small mass, once it is ejected from the liquid jet head, the kinetic energy is rapidly lost due to the viscous resistance of the atmosphere. With fine droplets that have lost their kinetic energy, the drop motion due to gravitational acceleration and the viscous resistance force due to the atmosphere are almost balanced, and it takes a long time to finish dropping.

  A liquid droplet that floats without adhering to the recording material and without falling down is called ink mist, and adheres to an object after a considerable time has elapsed after being ejected from the liquid ejecting head. When the adhesion target is the encoder or the optical sensor described above, an error occurs in the operation of the displacement detection means, and it becomes impossible to finally set an appropriate platen gap.

The following patent document discloses a technique for preventing contamination by ink mist as described above. Japanese Patent Application Laid-Open No. H10-228561 describes that ink misting can be reduced by measuring the distance between the recording medium and the liquid jet nozzle and selecting and executing the optimum recording operation mode. Japanese Patent Application Laid-Open No. 2004-228561 discloses a technique for preventing the ink mist from adhering with an electric repulsive force while keeping the linear encoder scale, linear encoder sensor, and guide rail of the ink jet printer at the same potential as the ink mist.
JP 2002-192714 A JP 2004-174749 A

  However, although the technique described in Patent Document 1 can reduce ink mist, it cannot completely eliminate ink mist. Thus, the problem of ink mist contamination remains.

  On the other hand, the ink jet printer described in Patent Document 2 includes a high voltage generator that is expensive and may cause an electric shock, and it is difficult to realize an inexpensive and safe liquid ejecting apparatus. Further, the range in which the ink mist can be adsorbed by static electricity is limited, and the generated ink mist is not completely completed. Furthermore, in an optical sensor often used in the above-described displacement detection means, a member formed of a non-conductive material is used as a functional element such as a light source or a light receiving element. It is difficult to apply this technique to this type of member.

  Therefore, in order to solve the above-mentioned problem, as a first embodiment of the present invention, a cylindrical guide part having a constant diameter and the distance from the central axis of the guide part are different at both ends of the guide part. And a guide shaft having a support portion for displacing the guide portion in a direction orthogonal to the central axis by rotating integrally with the guide portion, and reciprocating in a predetermined main scanning direction guided by the guide portion. A carriage, a liquid ejecting head that ejects liquid while being transported by the carriage, and a scale formed as an annular reflectance distribution around the rotation axis of the guide shaft on a circular surface that does not face the liquid ejecting head; A disc-shaped rotary encoder that is coaxially mounted on the guide shaft outside the range of reciprocating movement, and a sensor that detects the rotation of the guide shaft based on a change in the amount of reflected light from the disc due to the passage of the scale. When The liquid ejecting device is provided and a control unit for detecting a displacement of the guide portion on the basis of the output of the sensor. As a result, since the member related to the detection of the rotation of the guide shaft does not face the liquid ejecting head that is the source of ink mist, contamination by ink mist is reduced.

  Further, as a second embodiment of the present invention, a cylindrical guide portion having a constant diameter, and portions formed at both ends of the guide portion and having different distances from the central axis of the guide portion, A guide shaft having a support portion that displaces the guide portion in a direction perpendicular to the central axis by rotating integrally, a carriage that is guided by the guide shaft and reciprocates in a predetermined main scanning direction, and being conveyed to the carriage A liquid ejecting head that ejects liquid, and a circular surface that does not face the liquid ejecting head and has a scale formed as an annular magnetic flux distribution or permeability distribution around the rotation axis of the guide shaft. A disc-shaped rotary encoder mounted coaxially to the guide shaft outside the range, and a sensor for detecting the rotation of the guide shaft based on a change in magnetic flux density or permeability from the disc due to the passage of the scale The liquid ejecting device is provided and a control unit for detecting a displacement of the guide portion on the basis of the output of the sensor. Thereby, also in the liquid ejecting apparatus using the magnetic sensor, the contamination due to the ink mist is reduced, and the deterioration of the rotation detection accuracy of the guide shaft is reduced.

  In one embodiment, the liquid ejecting apparatus is disposed between a range of reciprocal movement of the carriage and the rotary encoder, and prevents the ink mist generated from the liquid ejecting head from adhering to the rotary encoder. A cover is provided. Thereby, contamination of the rotary encoder by ink mist is further reduced.

  Furthermore, as another embodiment, the liquid ejecting apparatus is disposed between a reciprocating range of the carriage and a rotation sensor, and prevents ink mist generated from the liquid ejecting head from adhering to the rotation sensor. A sensor cover is provided. Thereby, adhesion of ink mist to the rotation detection sensor is further reduced.

  According to a third aspect of the present invention, in a liquid ejecting apparatus that records on a recording material by ejecting the liquid onto the recording material transported to the recording area, the liquid ejecting head that ejects the liquid is transported. A rotation detection unit that detects rotation of a guide shaft that guides the guide shaft that guides a carriage that transports a liquid ejecting head that ejects liquid, and rotation of the guide shaft on a circular surface that does not face the liquid ejecting head A circular rotary encoder having a scale formed as an annular reflectance distribution around the axis and coaxially mounted on the guide shaft outside the range of reciprocation, and a circular surface formed by passing the scale A transport amount detection unit is provided that includes a sensor that detects rotation of the guide shaft based on a change in the amount of reflected light. As a result, a rotation detection unit that is less contaminated by ink mist and less deteriorated in rotation detection accuracy is supplied. By mounting the rotation detection unit on the liquid ejecting apparatus, the platen gap can be adjusted effectively.

  Further, as a fourth aspect of the present invention, in a liquid ejecting apparatus that records on a recording material by ejecting the liquid onto the recording material transported to the recording area, the liquid ejecting head that ejects the liquid is transported. A rotation detection unit that detects rotation of a guide shaft that guides the guide shaft that guides a carriage that transports a liquid ejecting head that ejects liquid, and rotation of the guide shaft on a circular surface that does not face the liquid ejecting head A disc-shaped rotary encoder that has a scale formed as an annular magnetic flux distribution or permeability distribution around the axis and is coaxially mounted on the guide shaft outside the range of reciprocal movement, and a circle by passing the scale A rotation detection unit is provided that includes a sensor that detects rotation of the guide shaft based on a change in magnetic flux density or magnetic permeability of the surface of the guide shaft. As a result, a rotation detection unit that is less contaminated by ink mist and less deteriorated in rotation detection accuracy is supplied. By mounting the rotation detection unit on the liquid ejecting apparatus, the platen gap can be adjusted effectively.

  Still further, as a fifth embodiment of the present invention, the guide portion has a cylindrical guide portion having a constant diameter, and portions formed at both ends of the guide portion and having different distances from the central axis of the guide portion. A guide shaft having a support portion that displaces the guide portion in a direction orthogonal to the central axis by rotating together with the guide shaft, a carriage that is guided by the guide portion and reciprocates in a predetermined main scanning direction, and is conveyed to the carriage. A recording head that discharges the liquid while having a scale formed as an annular reflectance distribution around the rotation axis of the guide shaft on a circular surface that does not face the recording head, and outside the range of reciprocation Based on a disc-shaped rotary encoder that is coaxially mounted on the guide shaft, a sensor that detects rotation of the guide shaft based on a change in the amount of reflected light from the disc due to the passage of the scale, and an output of the sensor guide Recording device is provided and a control unit for detecting the displacement. Thereby, also in the recording apparatus, since the member related to the rotation detection does not face the liquid ejecting head which is the generation source of the ink mist, the contamination due to the ink mist is reduced, and the deterioration of the rotation detection accuracy is reduced.

  Furthermore, as a sixth embodiment of the present invention, a cylindrical guide portion having a constant diameter, and portions formed at both ends of the guide portion and having different distances from the central axis of the guide portion, A guide shaft having a support portion that displaces the guide portion in a direction perpendicular to the central axis by rotating integrally, a carriage that is guided by the guide shaft and reciprocates in a predetermined main scanning direction, and being conveyed to the carriage A recording head that discharges liquid, and a circular surface that does not face the recording head, and has a scale formed as an annular magnetic flux distribution or magnetic permeability distribution around the rotation axis of the guide shaft. A disc-shaped rotary encoder mounted coaxially to the guide shaft on the outside, a sensor for detecting the rotation of the guide shaft based on a change in magnetic flux density or permeability from the disc due to the passage of the scale, and a sensor Recording device is provided and a control unit for detecting a displacement of the guide portion on the basis of the output. As a result, even in a recording apparatus including a rotation detection unit using a magnetic sensor, a member related to rotation detection does not face the liquid ejecting head that is the source of ink mist, so contamination by ink mist is reduced. Degradation of rotation detection accuracy is reduced.

  The above summary of the invention does not enumerate all necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 is an exploded perspective view showing a main internal mechanism 10 of an ink jet recording apparatus which is an embodiment of a liquid ejecting apparatus. As shown in the figure, the internal mechanism 10 has a side wall 112 extending toward the front (the right side wall is not visible in this figure) on both sides, and is recorded on the front and back of the frame 110 that stands. It is formed along the conveyance path of the paper 120.

  A paper support 130 is provided behind the frame 110, and the recording paper 120, which is a recording object, is loaded into the paper support 130. In the vicinity of the lower end of the paper support 130, a feeding unit hidden in the frame 110 is provided, and the recording sheet 120 is taken into the ink jet recording apparatus one by one by the feeding unit.

  A conveyance driving roller 170 that is rotationally driven is disposed in the vicinity of a position immediately below the frame 110, whereby the taken recording paper 120 is conveyed in the conveyance direction indicated by an arrow F in the drawing. A platen 160 and a discharge tray 180 are sequentially arranged in front of the transport driving roller 170 serving as a transport path. Further, on the right side of the platen 160, a wiping member 199 and a capping member 190 are sequentially arranged.

  The platen 160 positions the recording paper 120 in the height direction by supporting the recording paper 120 from below. Ink is ejected onto the recording paper 120 when the recording paper 120 is positioned on the platen 160. A recording head 156 that ejects ink onto the recording paper 120 is disposed above the height of the platen 160 and reciprocates over the entire width of the recording paper 120 while being transported to a carriage 150 described below.

  The recording head 156 is mounted on the lower surface of the carriage 150. The carriage 150 is supported by a guide shaft 140 inserted through a bearing portion 152 formed at the rear thereof. The guide shaft 140 is supported at both ends by the side wall portion 112 and the other side wall portion, and is disposed in parallel with the frame 110 and horizontally.

  Note that both ends of the guide shaft 140 are processed so as to be coupled to the side wall portion 112, but the region between the pair of side wall portions 112 has a constant cross-sectional shape, and the carriage 150 moves. The guide part 142 which guides is formed. Therefore, the carriage 150 guided by the guide shaft 140 can reciprocate in the main scanning direction which is orthogonal to the conveyance direction and horizontal.

  Further, the carriage 150 includes a cover 158 that can be opened and closed at an upper portion thereof, and an ink cartridge accommodated in the carriage 150 can be mounted or replaced. Ink supplied from the ink cartridge is ejected downward through the recording head 156.

  Further, a timing belt 151 hung on a pair of pulleys is disposed on the front surface of the frame 110. The timing belt 151 circulates according to the rotation of a pulley that is rotationally driven, and is displaced horizontally between the pulleys. Therefore, the carriage 150 can be reciprocated by coupling the horizontally moving part to the carriage 150.

  A substrate of the control unit 200 is mounted behind the frame 110. The control unit 200 retains image data to be recorded transferred from the outside, and performs conveyance control of the recording paper 120, movement control of the carriage 150, operation control of the recording head 156, and the like. Furthermore, signals from various detection means to be described later are obtained, and based on them, the operation of each part of the ink jet recording apparatus is monitored and reflected in the control.

  One of the detecting means is a rotary scale 172 attached to the end of the transport driving roller 170 outside the side wall portion 112. The rotary scale 172 has an annular scale that is coaxial with the rotation axis of the transport drive roller. By measuring the passage of the scale with a sensor (not shown) fixed to the side wall portion 112 side, an accurate rotation amount of the transport driving roller 170 can be detected. The rotation amount of the conveyance drive roller 170 corresponds to the conveyance amount of the recording paper 120 conveyed thereto, and is provided to the control unit 200 as control data.

  Although not shown, a sensor for detecting that the leading edge of the recording paper 120 to be conveyed has passed is provided in the vicinity of the conveyance driving roller 170. When this sensor detects that the leading edge of the recording paper 120 has passed, it notifies the control unit 200 of it.

  Further, between the front surface of the frame 110 and the carriage 150, a linear scale 153 stretched over the entire width of the movement range of the carriage 150 is disposed in parallel with the guide shaft 140. The linear scale 153 has a scale formed in the longitudinal direction. By measuring the passage of the scale with a sensor mounted on the back surface of the carriage 150, data corresponding to the amount of movement of the carriage 150 in the width direction of the recording paper 120 is obtained and provided to the control unit 200.

  The control unit 200 acquires various detection results as described above as control data, for example, accumulates the amount of rotation of the transport driving roller 170 from when the passage of the leading edge of the recording paper 120 is detected, and records the recording paper being transported. It is possible to extract an accurate position in the 120 conveyance direction. Further, the linear scale 153 can extract accurate positions of the carriage 150 and the recording head 156 in the main scanning direction. By controlling the operation or non-operation of the recording head 156 while referring to these extracted data, ink can be accurately ejected toward a desired region on the recording paper 120.

  Further, as described below, the ink jet recording apparatus has a function of moving the guide shaft 140 up and down to change the interval between the recording head 156 and the platen 160. As described above, the recording paper 120 during the recording operation is positioned by the platen 160. Further, since the recording head 156 is positioned by the guide shaft 140 via the carriage 150, the platen gap can be adjusted by this function.

  FIG. 2 is a view for explaining the support structure 20 of the guide shaft 140 in the internal mechanism 10 shown in FIG. In addition, the same reference number is attached | subjected to the same component as FIG. 1, and the overlapping description is abbreviate | omitted.

  As shown in the figure, the guide shaft 140 is inserted into vertically elongated holes 113 and 115 formed in the side wall portions 112 and 114 of the frame 110 at both ends thereof, and is displaced vertically with respect to the frame 110. it can. Since the guide shaft 140 is restricted from being displaced in the horizontal front-rear direction by the inner surface of the long hole 115, it can be displaced only in the up-and-down direction.

  Here, the guide shaft 140 is not directly supported by the frame 110 but is supported by an elevating mechanism provided outside the side wall portions 112 and 114 as described later. However, in FIG. 2, the lifting mechanism is hidden behind the side wall portion 114 and behind the rotary scale 172, and the pressed portion 334 that is a part of the lifting mechanism is visible through the side wall portion 114.

  FIG. 3 is a view showing the structure of the lifting mechanism 30 formed on the outside of the side wall 114 at the right end of the guide shaft 140 in the support structure 20 shown in FIG. As shown in the figure, the lifting mechanism 30 includes a rotation transmission mechanism including a plurality of gears 310, 320, 330, 340, 350, 360, and 370. Of these gears, the first stage gear 370 can be rotationally driven by a motor (not shown).

  The final stage gear 310 is coaxial with the guide shaft 140 and is integrally mounted on the guide shaft 140. Therefore, when the gear 370 is driven to rotate, the guide shaft 140 is finally rotated by the rotation transmitted through the gears 320, 330, 340, 350, 360 and 370. Thereby, the rotation is also transmitted to the other end of the guide shaft 140, that is, the side wall portion 112 side. Note that the pressed portion 334 that was visible inside the side wall portion 114 in FIG. 2 is formed on the back surface of the gear 330.

  Further, a part of the support member 380 is visible below the final stage gear 310. The support member 380 is fixed to the side wall portion 114. Further, the upper end thereof is in contact with a cam formed on the back surface of the gear 310.

  FIG. 4 is a diagram schematically showing the function of the cam mechanism 40 used in the elevating mechanism 30 shown in FIG. As shown in the figure, a cam 410 is formed integrally with the gear 310 on the side surface facing the side wall 114 of the gear 310. Therefore, the gear 310, the cam 410, and the guide shaft 140 all rotate together.

  The cam 410 has a sliding surface including a plurality of regions having different distances from the rotation axis of the guide shaft 140. The sliding surface of the cam 410 is in contact with a sliding portion 382 formed at the upper end of the support member 380 shown in FIG. Since the support member 380 is fixed with respect to the side wall portion 114, when the cam 410 rotates, the distance between the guide shaft 140 and the support member 380 changes. As described above, since the guide is guided by the long hole 115 of the side wall 114, the displacement of the guide shaft 140 is limited to the up and down direction. Accordingly, the gear 310 is rotated by rotationally driving the gear 310, and the guide shaft 140 is moved up and down by the action of the cam 410 to which the rotation is transmitted.

  Although illustration is omitted, a similar cam and support member are provided on the other end (left side in FIG. 1) of the guide shaft 140. Therefore, when rotation is transmitted by the guide shaft 140 itself, both ends of the guide shaft 140 are lifted and lowered simultaneously. In this way, the guide shaft 140 can be displaced in the ascending / descending direction while maintaining the level.

  As already described, the guide shaft 140 supports the carriage 150, and the recording head 156 is mounted on the carriage 150. Therefore, the recording head 156 can be moved up and down by operating the lifting mechanism 30 described above.

  On the other hand, the recording paper 120 which is a recording object is positioned on a platen 160 fixed to the frame 110. Accordingly, by raising and lowering the guide shaft 140, the interval of the recording head 156 with respect to the recording paper 120 can be changed. Thus, for example, even when the thickness of the recording paper 120 changes, a high-quality recording operation can be performed while maintaining an appropriate platen gap.

  Further, the lifting mechanism 30 has a lifting / lowering prohibiting mechanism that prohibits the lifting / lowering of the recording head 156 when the recording head 156 performs a recording operation above the platen 160. This prohibition of elevation prevents the recording quality from deteriorating significantly when the recording head 156 is raised or lowered during a recording operation due to an unexpected cause. Further, it is possible to prevent the moving recording head 156 from coming into contact with the platen 160 and being damaged.

  FIGS. 5 to 8 are views showing the structure and operation of the elevating prohibiting mechanism 60 formed around the gear 330 in the elevating mechanism 30 shown in FIG. Note that the movement of the carriage 150 is also involved in the operation of the elevation prohibiting mechanism 60.

  First, FIG. 5 is a view of the elevating mechanism 30 and the elevating prohibiting mechanism 60 in a state where the elevating operation is possible, as viewed from the front of the ink jet recording apparatus. As shown in the figure, the gears 320, 330 and 340 mesh with each other, and the transmission of rotation from the gears 370 to 310 shown in FIG. 3 is relayed.

  Here, paying attention to the shape of the side surface of the gear 330 on the side wall portion 114 side, a pair of locking projections 332 protrude from the side surface of the gear 330 toward the side wall portion 114. However, in this state, the locking protrusion 332 is opened, and the gear 330 can freely rotate. Such a state is formed by the carriage 150 approaching the inside of the side wall portion 114 and pressing the pressed portion 334 formed inside the gear 330 with the pressing portion 155 formed on the side surface thereof. .

  FIG. 6 shows a state where the carriage 150 has moved to the left with respect to the state shown in FIG. As shown in the figure, the pressing portion 155 moves away from the side wall portion 114 as the carriage 150 moves. Since the gear 330 is urged toward the side wall part 114 by the urging member 336, the gear 330 approaches the side wall part 114 when the pressing part 155 moves away from the side wall part 114. Therefore, the locking projection 332 provided on the gear 330 is also displaced toward the side wall portion 114, and the locking projection 332 eventually penetrates into the side wall portion 114.

  FIG. 7 is a perspective view showing the state shown in FIG. 6 as viewed from the inside of the side wall 114. As shown in the figure, the pressed portion 334 formed on the side surface of the gear 330 enters the inside through a notch formed in the side wall portion 114. In addition, a plurality of locking holes 117 are formed in the side wall portion 114 around the periphery, and locking protrusions 332 enter two of them. Therefore, the gear 330 cannot rotate when the side surface of the gear 330 is substantially in contact with the side wall 114.

  Turning again to FIG. 6, the gear 330 that is displaced in the axial direction and approaches the side wall 114 is disengaged from the gear 340. Therefore, transmission of rotation from the gear 370 to the gear 310 is interrupted between the gear 340 and the gear 330.

  In addition, the gear 320 which hits the downstream side of the gear 330 with respect to the transmission of rotation has a large thickness, and even if the gear 330 is displaced in the axial direction, the engagement is not disengaged. Therefore, when the rotation of the gear 330 is prohibited by the locking protrusion 332 and the locking hole 117, the gear 320 and the gear 310 cannot be rotated, and the raising / lowering of the guide shaft 140 is prohibited. Thus, when the carriage 150 moves away from the side wall 114, the rotation from the gear 370 is interrupted and the rotation of the gear 310 is prohibited, so that the guide shaft 140 is not displaced.

  FIG. 8 is a diagram illustrating another state in which the displacement of the guide shaft 140 is prohibited. As shown in the drawing, even in this state, the locking protrusion 332 of the gear 330 enters the locking hole 117 of the side wall 114 and does not rotate. However, the locking hole 117 into which the locking projection 332 enters is a hole different from the state shown in FIG. Therefore, although the guide shaft 140 is in a state where it does not move up and down, the guide shaft 140 at this time is at a height different from the state shown in FIG.

  With the function of the ascending / descending mechanism 60 as described above, in the ink jet recording apparatus provided with the internal mechanism 10, the guide shaft 140 can be raised and lowered only when the carriage 150 is approaching the side wall portion 114. Therefore, when the carriage 150 is in a recording operation area away from the side wall 114, the guide shaft 140 is prevented from moving up and down, and the operation of lowering the recording head 156 until it contacts the platen 160 or the recording paper 120 is prevented. Is done.

  As shown in FIGS. 5 and 6, a biasing member 346 is also attached to the gear 340 at the front stage of the gear 330, and the gear 340 is biased toward the side wall 114 in the axial direction thereof. The gear 340 is also mounted so that it can be displaced in its own axial direction. As a result, even when the gear 330 that has been disengaged is pushed by the pressing portion 155 and meshed with the gear 340 again, even if the phases of both gears are deviated, the gear 340 escapes to the outside. Teeth are not severely damaged.

  FIG. 9 is a perspective view showing a rotation detection unit formed by the sensor 146 and the rotary encoder 144 by viewing the support structure 20 shown in FIG. 2 from different angles. In addition, the same reference number is attached | subjected to the same component as another figure, and the overlapping description is abbreviate | omitted.

  As shown in the figure, this rotation detection unit includes a rotary encoder 144 mounted on the guide shaft 140 in the vicinity of the inside of the side wall portion 112, and a sensor fixed to the frame 110 between the side wall portion 112 and the rotary encoder 144. 146.

  The rotary encoder 144 is mounted inside the side wall portion 112 but outside the reciprocating range of the carriage 150 so as not to interfere with the reciprocating operation of the carriage 150. Further, it is a disk-shaped member that is mounted coaxially with the rotation shaft of the guide shaft 140 and rotates integrally with the guide shaft 140. Further, the mounting position is provided with a plurality of sector-like high reflectivity regions 148 having a higher optical reflectivity than other portions on the side surface of the rotary encoder 144 facing the side wall portion 112. It forms a scale by distribution.

  On the other hand, the sensor 146 includes a light source and a light receiving element, and is fixed to the frame 110 so as to face the surface of the rotary encoder 144 where the high reflectance region 148 is formed. Accordingly, the sensor 146 detects when the rotary encoder 144 rotates and the high reflectance region 148 faces itself.

  In this embodiment, the high reflectivity region 148 formed in the rotary encoder 144 corresponds to a position where the locking projection 332 of the gear 330 penetrates into the locking hole 117 of the side wall 114. Therefore, when the guide shaft 140 is rotated by the elevating mechanism 30 shown in FIG. 3, it can be detected by the sensor 146 that the locking protrusion 332 has come to the position where the locking hole 117 exists. Thus, the control unit 200 that has obtained the signal from the sensor 146 can perform control to stop the lifting mechanism 30 at an appropriate position.

  In this embodiment, the surface on which the high reflectivity region 148 of the rotary encoder 144 is formed does not face the reciprocation range of the recording head 156 corresponding to the guide portion 142 of the guide shaft 140. Accordingly, it is difficult for the ink mist generated from the recording head 156 to reach the high reflectance region. Further, since the rotary encoder 144 is positioned between the reciprocating region of the recording head 156 and the sensor 146 and the surface of the sensor 146 is blocked by the rotary encoder 144, it is difficult for ink mist to adhere to the sensor 146.

  Furthermore, in the above embodiment, the scale is formed by the highly reflective region 148, but the scale can be formed by other means. For example, a scale may be formed as a magnetic flux density distribution or a magnetic permeability distribution using a material having a magnetic susceptibility or a magnetic permeability different from that of the disk of the rotary encoder 144. In this case, as the sensor 146, a magnetic sensor that can detect a change in magnetic flux density or a permeability meter that itself has a magnetic field generating means is used.

  Note that so-called magnetic ink containing a magnetic material may be used in applications that require high security against falsification of recorded matter, such as an ink jet check writer. In such applications, even if a rotation detection unit using a magnetic sensor is mounted, the detection accuracy deteriorates due to the influence of contamination by ink mist. Therefore, even when a magnetic sensor is used, it is beneficial to prevent ink mist from adhering to the sensor 146 and the rotary encoder 720.

  FIG. 10 is a diagram showing another embodiment of the rotation detection unit 70 that detects the rotation of the guide shaft 140, and is a sectional view in which the periphery of the rotary encoder 144 is taken out and enlarged. Also in this figure, the same reference numerals are given to the same constituent elements as those in the other drawings, and redundant description is omitted.

  As shown in the figure, in this embodiment, the rotary encoder cover 710 that is attached to the side wall portion 112 and surrounds the periphery of the rotary encoder 144 and the guide shaft 140 side are attached to the rotary encoder cover 710 from the outer side. Another rotary encoder cover 720 surrounding the rotary encoder 144 is provided. In this embodiment, the sensor 146 is fixed to the side wall portion 112.

  In the rotation detection unit as described above, the rotary encoder cover 710 extends from the side wall portion 112 to the outside of the rotary encoder 144, and the side surface facing the side wall portion 112 of the rotary encoder 144 is the side wall portion 112 and the rotary encoder. Surrounded by a cover 710. Further, another rotary encoder cover 720 covers the outer side.

  Thus, the rotary encoder covers 710 and 720 substantially completely surround the rotary encoder 71 and serve as a barrier against the ink mist generated from the recording head 156. Therefore, ink mist generated in the recording head 156 does not reach the rotary encoder 144. Further, since the sensor 146 is also housed in the rotary encoder covers 710 and 720, ink mist does not adhere.

  The rotary encoder covers 710 and 720 can be additionally attached to an ink jet recording apparatus that does not initially include the rotary encoder covers 710 and 720. Therefore, it is meaningful to supply the rotary encoder covers 710 and 720 alone.

  FIG. 11 is a view showing another embodiment of the rotation detection unit 80 that detects the rotation of the guide shaft 140, and is an enlarged perspective view showing the periphery of the rotary encoder 144. Also in this figure, the same reference numerals are given to the same components as those in the other drawings, and redundant description is omitted.

  As shown in the figure, the rotation detection unit 80 includes a chopper type rotary encoder 144 and a sensor 146 fixed to the frame 110, and is further fixed to the front surface of the frame 110 to cover the sensor 146. A sensor cover 810 is provided. In this embodiment, since the chopper 145 that forms the scale of the rotary encoder 144 is sufficiently large and the interval is large, even if ink mist adheres thereto, there is little deterioration in the rotation detection accuracy of the guide shaft 140. However, sensor 146 is still subject to contamination. On the other hand, the sensor cover 810 functions as a barrier against the ink mist between the sensor 146 and the reciprocating movement area of the recording head 156 that is a source of ink mist. Remarkably reduced.

  The sensor cover 810 can also be additionally attached to an ink jet recording apparatus that does not include the sensor cover 810 at the beginning. Therefore, it is meaningful to supply the sensor cover 810 alone.

  As described above in detail, in this ink jet type liquid ejecting apparatus, since the rotation detecting means including the rotary encoder 144 and the sensor 146 is not easily contaminated by the ink mist, the ink mist is generated with the operation of the recording head 156. Even so, the rotation detection function of the guide shaft 140 does not deteriorate. Therefore, the platen gap can be adjusted reliably and accurately, and a high-quality recording operation can be maintained. Alternatively, the rotary encoder 144, the sensor 146, and the rotary encoder covers 710, 720, and 810 corresponding to the rotary encoder 144, the rotary encoder covers 710, 720, and 810 may be combined and supplied as a rotation detection unit, and added to the existing components and mounted.

  Although the ink jet recording apparatus has been described as an example, the liquid ejecting apparatus includes a liquid crystal display color filter manufacturing apparatus having a material ejecting head as a liquid ejecting head, and an electrode material (conductive paste) ejecting as a liquid ejecting head. Examples include an organic EL display having a head, an electrode forming apparatus such as an FED (surface emitting display), a biochip manufacturing apparatus having a biological organic matter ejecting head and a precision pipette as a liquid ejecting head, and the like. The recording material generally refers to a material to which the liquid ejected from the liquid ejecting head can be attached, and includes a circuit board, a disk-shaped optical recording medium, a preparation and the like in addition to the recording paper.

  Furthermore, although the present invention has been described using the embodiment, the technical scope of the present invention is not limited to the scope described in the embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. Further, it is apparent from the description of the scope of claims that the embodiment added with such changes or improvements can be included in the technical scope of the present invention.

1 is a perspective view showing an internal mechanism 10 of an ink jet recording apparatus. The perspective view which shows the support structure 20 of the guide shaft 140 which supports the carriage 150. FIG. The figure which shows typically the raising / lowering mechanism 30 which displaces the guide shaft 140 to an raising / lowering direction. The figure which shows the structure of the cam mechanism 40 which can be used with the raising / lowering mechanism 30 shown in FIG. The figure which looked at the raising / lowering prohibition mechanism 60 of the open state from the front. The front view which shows the raising / lowering prohibition mechanism 60 of a raising / lowering prohibition state from the same viewpoint as FIG. The perspective view which shows the raising / lowering prohibition mechanism 60 in a raising / lowering prohibition state. The perspective view which shows the raising / lowering prohibition mechanism 60 in the raising / lowering prohibition state different from FIG. FIG. 4 is a perspective view showing rotation detection means for a guide shaft 140 in the internal mechanism 10. The perspective view which shows the rotation detection unit 70 provided with the rotary encoder cover 710,720. The perspective view which shows the rotation detection unit 80 provided with the sensor cover 810. FIG.

Explanation of symbols

10 internal mechanism, 20 support structure, 30 lifting mechanism, 40 cam mechanism, 60 lifting prohibition mechanism, 70, 80 rotation detection unit, 110 frame, 112, 114 side wall, 113, 115 long hole, 117 locking hole, 120 recording Paper, 130 Paper support, 140 Guide shaft, 142 Guide section, 144 Rotary encoder, 146 Sensor, 150 Carriage, 151 Timing belt, 152 Bearing section, 153 Linear scale, 155 Press section, 156 Recording head, 160 Platen, 170 Conveyance drive Roller, 172 Rotary scale, 180 discharge tray, 190 capping member, 199 wiping member, 200 control unit, 310, 320, 330, 340, 350, 360, 370 gear, 332 locking projection, 334 pressed part 336, 346 Energizing member, 380 Support member, 382 Sliding part, 410 Cam, 710, 720 Rotary encoder cover, 810 Sensor cover

Claims (8)

A cylindrical guide portion having a constant diameter, and portions formed at both ends of the guide portion, the portions having different distances from the central axis of the guide portion, and rotating together with the guide portion, the center A guide shaft having a support portion that displaces the guide portion in a direction orthogonal to the shaft;
A carriage that is guided by the guide portion and reciprocates in a predetermined main scanning direction;
A liquid ejecting head that ejects liquid while being transported to the carriage;
The circular surface on the side not facing the liquid ejecting head has a scale formed as an annular reflectance distribution around the rotation axis of the guide shaft, and is coaxial with the guide shaft outside the reciprocating range. A disk-shaped rotary encoder mounted on the
A sensor that detects the rotation of the guide shaft based on a change in the amount of reflected light from the disk due to the passage of the scale;
A liquid ejecting apparatus comprising: a control unit that detects displacement of the guide unit based on an output of the sensor. A cylindrical guide portion having a constant diameter, and portions formed at both ends of the guide portion, the portions having different distances from the central axis of the guide portion, and rotating together with the guide portion, the center A guide shaft having a support portion that displaces the guide portion in a direction orthogonal to the shaft;
A carriage guided by the guide shaft and reciprocating in a predetermined main scanning direction;
A liquid ejecting head that ejects liquid while being transported to the carriage;
The circular surface not facing the liquid ejecting head has a scale formed as an annular magnetic flux distribution or permeability distribution around the rotation axis of the guide shaft, and the guide is outside the range of the reciprocating movement. A disc-shaped rotary encoder mounted coaxially on the shaft;
A sensor for detecting rotation of the guide shaft based on a change in magnetic flux density or magnetic permeability from the disk due to the passage of the scale;
A liquid ejecting apparatus comprising: a control unit that detects displacement of the guide unit based on an output of the sensor.   The rotary encoder cover is disposed between the reciprocating range of the carriage and the rotary encoder, and prevents the ink mist generated from the liquid ejecting head from adhering to the rotary encoder. Item 3. The liquid ejecting apparatus according to Item 2.   3. The sensor cover according to claim 1, further comprising a sensor cover that is disposed between the reciprocating range of the carriage and the sensor and prevents ink mist generated from the liquid ejecting head from adhering to the sensor. The liquid ejecting apparatus described. In a liquid ejecting apparatus that performs recording on the recording material by ejecting liquid onto the recording material conveyed to the recording area, rotation of a guide shaft that guides conveyance of the liquid ejecting head that ejects the liquid is detected. A rotation detection unit,
A guide shaft that guides a carriage that transports the liquid ejecting head that ejects the liquid;
The circular surface on the side not facing the liquid ejecting head has a scale formed as an annular reflectance distribution around the rotation axis of the guide shaft, and is coaxial with the guide shaft outside the reciprocating range. A disk-shaped rotary encoder mounted on the
A conveyance amount detection unit comprising: a sensor that detects rotation of the guide shaft based on a change in the amount of reflected light on the circular surface due to the passage of the scale. In a liquid ejecting apparatus that performs recording on the recording material by ejecting liquid onto the recording material conveyed to the recording area, rotation of a guide shaft that guides conveyance of the liquid ejecting head that ejects the liquid is detected. A rotation detection unit,
A guide shaft that guides a carriage that transports the liquid ejecting head that ejects the liquid;
The circular surface not facing the liquid ejecting head has a scale formed as an annular magnetic flux distribution or permeability distribution around the rotation axis of the guide shaft, and the guide is outside the range of the reciprocating movement. A disc-shaped rotary encoder mounted coaxially on the shaft;
A rotation detection unit comprising: a sensor that detects rotation of the guide shaft based on a change in magnetic flux density or magnetic permeability of the circular surface due to passage of the scale. A cylindrical guide portion having a constant diameter, and portions formed at both ends of the guide portion, the portions having different distances from the central axis of the guide portion, and rotating together with the guide portion, the center A guide shaft having a support portion that displaces the guide portion in a direction orthogonal to the shaft;
A carriage that is guided by the guide portion and reciprocates in a predetermined main scanning direction;
A recording head for discharging liquid while being conveyed to the carriage;
A circular surface on the side not facing the recording head has a scale formed as an annular reflectance distribution centered on the rotation axis of the guide shaft, and is coaxial with the guide shaft outside the range of reciprocal movement. A mounted disk-shaped rotary encoder;
A sensor that detects the rotation of the guide shaft based on a change in the amount of reflected light from the disk due to the passage of the scale;
A recording apparatus comprising: a control unit that detects a displacement of the guide unit based on an output of the sensor. A cylindrical guide portion having a constant diameter, and portions formed at both ends of the guide portion, the portions having different distances from the central axis of the guide portion, and rotating together with the guide portion, the center A guide shaft having a support portion that displaces the guide portion in a direction orthogonal to the shaft;
A carriage guided by the guide shaft and reciprocating in a predetermined main scanning direction;
A recording head for discharging liquid while being conveyed to the carriage;
The guide shaft has a scale formed as an annular magnetic flux distribution or permeability distribution around the rotation axis of the guide shaft on a circular surface that does not face the recording head, and the guide shaft is outside the reciprocating range. A disc-shaped rotary encoder coaxially mounted on
A sensor for detecting rotation of the guide shaft based on a change in magnetic flux density or magnetic permeability from the disk due to the passage of the scale;
A recording apparatus comprising: a control unit that detects a displacement of the guide unit based on an output of the sensor.

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