JP2010274486A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make first and second recording heads go up and down by a small drive force. <P>SOLUTION: In an image forming apparatus which includes a first carriage equipped with the first recording head, a second carriage equipped with the second recording head and a drive source, the first carriage includes a first drive transmission means by which a drive force from the drive source is transmitted and a first head rise/fall means for making the first recording head go up and down by the drive force transmitted by the first drive transmission means. The second carriage includes a second drive transmission means by which the drive force from the drive source is transmitted and a second head rise/fall means for making the second recording head go up and down by the drive force transmitted by the second drive transmission means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus using an ink jet system such as a printer, a copier, and a FAX.

In a conventional image forming apparatus using an ink jet system, an image is formed on a recording medium using a recording head composed of a liquid ejection head that ejects droplets of recording liquid (ink). The distance between the nozzle surface of the recording head and the recording surface of the recording medium needs to be kept constant. This is because there are various thicknesses of the recording medium, and if the distance is not constant, ink cannot be printed at a target position by reciprocal printing.
Therefore, as described in Patent Document 1, in order to protect the recording head, the recording head is mounted on a carriage, and the carriage is moved up and down for each guide and frame in the main scanning direction, so that the nozzles of the recording head There is an image forming apparatus that adjusts the distance between a surface and a recording medium.
In Patent Document 2, a holder member for holding a plurality of heads is mounted in a carriage, and the holder member is installed on a plurality of eccentric cams arranged in parallel in the carriage, and the eccentric cams are simultaneously rotated at the same angle. A technique for moving up and down a plurality of heads together with the holder is described.
The image forming apparatuses described in Patent Documents 3 and 4 perform monochrome printing and color printing. This image forming apparatus uses a monochrome carriage to suppress unnecessary ink consumption such as idle ejection of color ink during monochrome printing. That is, this image forming apparatus has a monochrome carriage and a color carriage, and a monochrome recording head and a color recording head are mounted on each. In monochrome printing, only the monochrome carriage is driven and unnecessary color ink is not used. Therefore, the color recording head is protected without being driven. These two carriages can be separated and connected.

The image forming apparatus described in Patent Document 1 is a mechanism suitable for downsizing. However, an image forming apparatus that prints on a large-sized wide-width recording medium is not suitable for a mechanism that raises and lowers the carriage together with the main scanning guide and frame because the main scanning direction is long and the guide, frame, and carriage are heavy.
In the image forming apparatus described in Patent Document 2, there is no description of an application example to a configuration having two carriages. If the same configuration is mounted on each carriage, the cam drive source in the two carriages is provided in each carriage. This leads to an increase in carriage weight and width.
In addition, a technique for adjusting the gap between the nozzle surfaces of the two recording heads and the recording medium of the image forming apparatuses described in Patent Documents 3 and 4 is not disclosed.
Therefore, the present invention provides an image forming apparatus that appropriately adjusts the gap between the nozzle surface of the recording head and the recording medium, even if there are two carriages.

  In order to achieve the object, an image forming apparatus according to the present invention includes a first carriage having a first recording head and a second carriage having a second recording head. The first carriage includes a first drive transmission unit that transmits a driving force from the driving source, and a first carriage that moves the first recording head up and down by the driving force transmitted by the first drive transmission unit. The second carriage has a first head raising / lowering means, and the second carriage raises and lowers the second recording head by the second driving transmission means to which the driving force from the driving source is transmitted and the driving force transmitted by the second driving transmission means. 2 head lifting means.

  In the image forming apparatus of the present invention, the gap between the nozzle surface of the recording head mounted on the two carriages and the recording medium is adjusted appropriately.

FIG. 1A is a front view of the image forming apparatus of the present embodiment, and FIG. 1B is a side view. 1 is a perspective view of a recording apparatus 100 according to an embodiment. FIG. 2 is a schematic view of the recording apparatus 100 according to the first embodiment when viewed from directly above. 4A is a perspective view of the recording head, FIG. 4B is a perspective view of the head holder, FIG. 4C is a perspective view of the head holder assembly, and FIG. FIG. 4E is a perspective view of the carriage, and FIG. 4E is a perspective view of the carriage assembly. It is a side view of the carriage of a present Example. It is a front view of the carriage of the present embodiment. It is the figure which looked at the carriage of the present Example from right below. It is a perspective view, such as a slide cam of a present Example. FIG. 9A is a side view when the head holder is in the normal position, and FIG. 9B is a side view when the head holder is in the raised position. It is a perspective view, such as a slide cam of another Example. It is side views, such as a slide cam of another Example. FIG. 5 is a schematic view seen from directly above when the recording heads of the first carriage and the second carriage are omitted. It is the figure which showed the 1st method of carriage connection. It is the figure which showed the 2nd method of carriage connection. It is the figure which showed the 3rd method of carriage connection. FIG. 16A is a diagram illustrating a functional configuration example of the first joint portion 23 and the like, and FIG. 16B is a diagram illustrating a functional configuration example of the second joint portion 22 and the like. FIG. 17A is a diagram showing another functional configuration example such as the first joint portion 23, and FIG. 17B is a diagram showing another functional configuration example such as the second joint portion 22. . It is the figure which showed the functional structural example etc. of the control part It is the figure which showed the processing flow of the control part.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In addition, the same number is attached | subjected to the process which performs the structure part which has the same function, and the same process, and duplication description is abbreviate | omitted.

  FIG. 1A shows a front view of the image forming apparatus 1000 according to the first embodiment, and FIG. 1B shows a side view. As shown in FIG. 1A, the image forming apparatus 1000 according to the present embodiment can be roughly divided into a recording apparatus 100 and a paper feeding unit 200. The maintenance mechanism 8 will be described later. As shown in FIG. 1B, the paper feed roller 80 is a part of the paper feed unit 200 and plays a role of transporting a recording medium (for example, paper).

FIG. 2 mainly shows a perspective view of the recording apparatus 100. FIG. 3 is a schematic view of the recording apparatus 100 showing the first carriage 5 and the second carriage 6 as viewed from above. In the following description, the distance between the nozzle surface of the recording head and the recording surface of the recording medium is referred to as a gap L, the X ₁ X ₂ direction is referred to as a main scanning direction, and the Y ₁ Y ₂ direction is referred to as a sub-scanning direction (main scanning direction). The Z ₁ Z ₂ direction is referred to as the vertical direction.
The ink jet recording apparatus is a serial type ink jet recording apparatus, and includes the recording apparatus 100 and a support base 160 that supports the recording apparatus 100 in the example of FIG. Inside the recording apparatus 100, the guide rod 1 and the sub guide 2 are spanned and fixed to the left side plate 3 and the right side plate 4. The first carriage 5 and the second carriage 6 have a bearing portion 14 ₁ and a bearing portion 14 ₂ , respectively. The guide rod 1 is supported by the bearing portion 14 ₁ and the bearing portion 14 ₂ . Further, the sub-guide 2 is sub guide receiving portions 16 _1, it is bearing the sub guide receiving portion 16 _2. With these bearings, the first carriage 5 and the second carriage 6 are slidably held in the main scanning direction (X ₁ X ₂ direction).
In this example, the first carriage 5 is equipped with _two first recording heads 7 ₁ and 7 ₂ for ejecting black (K) ink droplets. The second carriage 6 yellow (Y), magenta (M), the second recording head ₇ 3 for ejecting ink droplets of respective colors of cyan _{(C), 7 4, 7} 5 are mounted. The two first recording heads 7 ₁ and 7 ₂ are arranged with their positions shifted in the main scanning direction and the sub-scanning direction, respectively. Further, each recording head _71, 7 _2, 7 _3, 7 4, ₇ not shown in _5, but the sub-tank for supplying ink to the recording heads 7 are provided integrally. In the first embodiment, the first recording heads 7 ₁ and 7 ₂ are accommodated in the first head holder 27, and the first head holder 27 is mounted on the first carriage 5. Further, the second recording head ₇ 3-7 ₅ stored in the second head holder 41, the second head holder 41 is mounted on the second carriage 6. Details will be described later. In FIG. 3, the first head holder 27 and the second head holder 41 are omitted, and the relationship between the recording head, the head holder, and the carriage will be described later.
The first carriage 5, a main scanning mechanism for moving the scanning of the second carriage 6 is mainly the scanning direction of the main one is arranged on the side scanning motor 9, a driving pulley 12 ₁ disposed in the vicinity of the main scanning motor 9, the main a driven pulley 12 ₂ arranged in the scanning direction the other side, and a timing belt 10 wound around them. Incidentally, the driven pulley 12 ₂ is urged outward (right side plate 4 side) by tensioner 13 (tension is applied).
A part of the timing belt 10 is fixedly held by a belt holding portion 15 provided on the back side of the first carriage 5, and the first carriage 5 is driven in the main scanning direction X ₁ by the main scanning driving force from the main scanning motor 9. it is possible to reciprocate in X _2.
An encoder sheet 11 for detecting the main scanning position of the first carriage 5 is arranged along the main scanning direction of the first carriage 5. 1 the first encoder sensor 17 provided in the first carriage _5, the second encoder sensor 17 ₂ is provided on the second carriage 6, by reading the encoder sheet 11, the first carriage 5, the main scanning position of the second carriage 6 Can be detected.
Further, the first carriage 5 and the second carriage 6 have a first coupling mechanism 18 ₁ and a second coupling mechanism 18 ₂ , respectively. The first carriage 5 and the second carriage 6 is connected or separated by a first coupling mechanism 18 ₁ and the second coupling mechanism 18 _2. The first carriage 5 and the second carriage 6 are coupled by the first coupling mechanism 18 ₁ and the second coupling mechanism 18 ₂ , and the second carriage 6 is moved by the driving force from the main scanning motor 9 transmitted to the first carriage 5. The first carriage 5 and the second carriage 6 are integrally driven by main scanning. Examples of configurations of the first connecting mechanism 18 ₁ and the second connecting mechanism 18 ₂ include means for switching the connection by turning on and off an electromagnet, and a mechanism for locking the other carriage by a mechanism having a hook shape.
In the example of FIG. 3, the drive source 20 is arranged on the outer wall of the right side plate 4, and the first carriage 5 and the second carriage 6 are arranged in this order from the side closer to the drive source 20. The second joint portion 21 of the second carriage 6 is connected to the drive connecting portion 19 of the drive source 20, and the second head holder 41 is raised and lowered by the driving force from the drive source 20 (details of raising and lowering will be described later). . The elevation of the first head holder 27, since the first coupling mechanism 18 ₁ is a connecting means and a second coupling mechanism 18 ₂ is connected, the first joint portion 23 and the second joint portion 22 is connected As a result, the first drive transmission means 700 and the second drive transmission means 800 are connected at a predetermined location (details will be described later). The driving force from the driving source 20 is transmitted to the first head holder 27, and the first head holder 27 is raised and lowered. In this example, the first drive transmission means 700 is the first joint part 23, and the second drive transmission means 800 is the second joint part 21 connected to the drive connection part 19.
The first time of driving the carriage only 5 without connecting the first carriage 5 and second carriage 6 is on standby in the state with a protected second recording head 7 _{3-7 5} of the second carriage 6 placing it possible, second recording head 7 _{3-7 5} lifetime of together with attained the second carriage 6, it is possible to suppress wasteful consumption of color inks during monochrome printing.
Of the main scanning areas of the first carriage 5 and the second carriage 6, in the recording area, the recording medium 150 is intermittently conveyed in the sub-scanning direction by a paper feed mechanism (not shown). In addition, a maintenance mechanism 8 that performs maintenance and recovery of the recording head 7 is disposed in one end side area of the main scanning area.

When a certain period of time elapses, the recording liquid of the recording head thickens and ink clogging may occur. Therefore, the maintenance mechanism 8 discharges droplets that do not contribute to image formation in order to discharge the thickened recording liquid. The discharged recording liquid is stored in a waste liquid tank (not shown).
Also, a cartridge 70 (see FIG. 2) containing ink of each color to be supplied to the sub tank of the first recording head is located outside the carriage movement area in the main scanning direction or below the other end of the carriage movement area. It is detachably attached to.
The first carriage 5 includes a first head lifting / lowering unit 500 and a first drive transmission unit 700, and the second carriage 6 includes a second head lifting / lowering unit 600 and a second drive transmission unit 800.
As described above, the control unit 300 (see FIG. 1B) of the image forming apparatus 1000 according to the present exemplary embodiment performs main scanning on the first carriage 5 alone or on the first carriage 5 and the second carriage 6 connected to each other. It is moved in the direction a, while feeding the recording medium 150 in the sub-scanning direction intermittently, by ejecting droplets by driving in response to the first, second recording head 7 _{1-7 5} image information, recording A predetermined image is formed on the medium 150.
Next, the relationship among the first recording heads 7 ₁ and 7 ₂ , the first head holder 27, and the first carriage 5 will be described. Since the relationship between the second recording heads 7 _{3 to} 7 ₅ , the second head holder 41, and the second carriage 6 is the same, illustration is omitted. Figure 4 shows the first recording head ₇ 1, _{7 2} of the perspective view (A), a in FIG. 4 (B), shows a perspective view of the first head holder 27, the first recording head 7 in FIG. 4 (C) _1, 7 shows a perspective view of the ₂ first head holder 27 was housed (the head holder assembly) shows a perspective view of the first carriage 5 in FIG. 4 (D), the head holder assembly in FIG. 4 (E) The perspective view of the accommodated 1st carriage 5 (carriage assembly) is shown.
As shown in FIG. 4A, each of the first recording heads 7 ₁ and 7 ₂ has first nozzle surfaces 7a ₁ and 7a ₂ on the bottom surface.
As shown in FIG. 4B, the first head holder 27 has a substantially rectangular parallelepiped shape, and has a head holder accommodating portion 27a by opening the top. The first head holder 27 has a shape in which the front of the two side walls 27c on both sides in the longitudinal direction (sub-scanning direction) is cut off. Two head holder holes 27 b are formed on the bottom surface of the first head holder 27. When the two first recording heads 7 ₁ and 7 ₂ are accommodated in the head holder accommodating portion 27a, the first nozzle surfaces 7a ₁ and 7a ₂ are exposed from the two head holder holes 27b (FIG. 4C )reference). In this example, the head holder holes are formed so as to be shifted in the sub-scanning direction. Further, head holder convex portions 27d are formed on the two side walls 27c along the longitudinal direction (sub-scanning direction). The lower surface of the head holder protrusion portion 27d _{(Z 1} direction), a head holder cam surface 27e (uneven surface). The role of the head holder cam surface 27e will be described later.
The first head holder 27 that houses the first recording head shown in FIG. 4B is raised and lowered by the first head lifting means 500, and the second head holder 41 that houses the second recording head is raised and lowered by the second head. It is moved up and down by means 600.
The first carriage 5 will be described with reference to FIG. The first carriage 5 has a stepped portion 5a, has a first carriage accommodating portion 5b on the lower front side, and has a second carriage accommodating portion 5e on the upper rear side. A carriage hole 5c is formed on the bottom surface of the first carriage accommodating portion 5b. As shown in FIG. 4E, the head holder assembly is accommodated in the first accommodating portion 5b, and the nozzle surfaces 7a ₁ and 7a ₂ of the two recording heads 7 ₁ and 7 ₂ are exposed from the carriage hole 5c. The

The second housing part 5c, ₁ and the first encoder sensor 17 is mounted, in the rear of the first carriage 5, the bearing portion 14 ₁ is provided.
The first carriage 5 and the second carriage 6 have a first head lifting means 500 and a second head lifting means 600, respectively. The first head holder 27 accommodating the first recording heads 7 ₁ and 7 ₂ can be moved up and down by the first head lifting and lowering means 500 in the vertical direction (Z ₁ Z ₂ direction). The second head holder 41 housing the second recording head ₇ 3-7 ₅ can lift the height direction by the second head lifting means 600 _(Z 1 _{Z 2} direction). The first recording head ₇ 1, _{7 2,} second by the elevating movement of the recording head ₇ 3-7 _5, the first recording head ₇ 1, _{7 2} of the first nozzle face _7a 1, 7a ₂ and the second recording heads 7 _3-7 and the second nozzle face _7a 3 _{~7a 5} of _5, it is possible to adjust the gap L between the printing surface of the recording medium 150.
Further, the gap L to be adjusted may be input by the user from an input unit (not shown) by visually checking the thickness of the recording medium and the value of the gap L corresponding to the thickness of the recording medium. When image data on a PC terminal is transmitted to the image forming apparatus 1000 for printing, the user inputs the thickness of the recording medium to the PC terminal and measures the gap L in the PC terminal. Then, the measured gap L may be transmitted together with the image data. Further, the gap L corresponding to the thickness can be calculated using a known technique in which the image forming apparatus 1000 automatically measures the thickness of the recording medium. With this configuration, the user does not need to obtain the thickness of the recording medium.
Next, the 1st head raising / lowering means 500 is demonstrated. Since the second head lifting / lowering means 600 has the same configuration, illustration and description are omitted. In this embodiment, the first head raising / lowering means 500 and the second head raising / lowering means 600 have cam mechanisms, but any other mechanism can be used as long as the first head holder 27 and the second head holder 41 are raised and lowered. May be.
FIG. 5 shows a schematic view of the first carriage 5 as seen from the side (X _{2 in} FIG. 2), and FIG. 6 shows a schematic view of the first carriage 5 as seen from the front (Y _{1 in} FIG. 2). FIG. 7 shows a schematic view of the first carriage 5 as viewed from below. Since the same applies to the second carriage 6, the illustration is omitted.
As shown in FIGS. 5 and 6, each side wall portion 5 d formed on both sides in the longitudinal direction (sub-scanning direction) of the first carriage 5 has a convex elastic member press along the longitudinal direction. Part 50 is formed. The upper surface of the cam convex portion 27d (the surface opposite to the cam surface 27e, hereinafter referred to as “cam convex portion upper surface”) 27f and one end of the elastic member 31 are pressed against each other, and the lower surface of the elastic member pressing portion 50 50a (surface facing the cam convex portion upper surface 27f) and the other end of the elastic member 31 are in pressure contact. As a result, the cam protrusion 27d is urged downward by the elastic member 31. Due to this downward bias, even if the first carriage 5 vibrates, the first head holder 27 does not move and vibrate.
Further, a slide cam 24 is provided between the bottom surface 5b of the first carriage 5 and the cam projection 27d so as to face each of the two cam projections 27d (on both sides of the bottom surface 5b). The two slide cams 24 are arranged in parallel, and the two slide cams 24 move in the longitudinal direction (sub-scanning direction) of the first carriage 6. FIG. 8 is a perspective view of the slide cam 24 and the like. The principle of the two slide cams 24 moving in the sub-scanning direction will be described with reference to FIG. In the following description, the two slide cams are indicated as slide cams 241 and 242, respectively. In addition, when referring to the two slide cams collectively, the slide cam 24 may be used. As shown in FIG. 7, a drive transmission shaft 26 is disposed behind the first carriage 5.
As shown in FIG. 8, racks 241a and 242a are formed at the tips of the slide cams 241 and 242, respectively. On the other hand, a first joint portion 23 is provided at one end of the drive transmission shaft 26, a pinion 281 is provided on the other end side of the drive transmission shaft 26, and a pinion 282 is provided on each inner side of the joint portion 24. The rack 241a and the pinion 281 are arranged so that the slide cam 241 and the drive transmission shaft 26 are orthogonal to each other. Similarly, the rack 242a and the pinion 282 are meshed so that the slide cam 242 and the drive transmission shaft 26 are orthogonal to each other. In the following description, the two pinions 281 and 282 may be collectively referred to as the pinion 28.
In addition, the first joint portion 23 is rotated integrally with the first joint portion 23 and the drive transmission shaft 26 when the driving force from the driving source 20 is transmitted to the first joint portion 23. When the drive transmission shaft 26 is rotated, the slide cam 241 reciprocates in the sub-scanning direction (the arrow direction in FIG. 8) due to the engagement between the rack 241a and the pinion 281. Similarly, the slide cam 242 reciprocates in the sub-scanning direction due to the engagement between the rack 242a and the pinion 282. In FIG. 5, the movement direction of the slide cam is shown as a slide cam movement direction C.
10 and 11, which will be described later, a second joint portion 22 is provided on one end side of the drive transmission shaft of the second carriage 6 on the first carriage 6 side, and the other end (that is, a drive source). The second joint portion 21 is provided on the side.
9A and 9B are diagrams for explaining that the first head holder 27 moves in the height direction due to the movement of the slide cams 241 and 242 in the sub-scanning direction. On the head holder cam surface 27e of the cam convex portion 27d, a convex portion 27g having a slope 27f and a convex portion 27j having a slope 27h are formed. Further, a concave portion 27i having an inclined surface 27h is formed between the convex portion 27g and the convex portion 27j. The cam surface of the slide cam 24 has a recess 24c having a slope 24b and a recess 24e having a slope 24d. And it has the convex part 24f which has the inclined surface 24d between the recessed part 24c and the recessed part 24e. As shown in FIG. 9A, a space D is provided between the cam convex portion 27d and the slide cam 24 so that the convex portion 27g is accommodated in the concave portion 24c and the convex portion 27j is accommodated in the concave portion 24e. However, the first head holder 27 is in the lowest position (hereinafter referred to as “normal position”).
Further, when the driving force from the driving source 20 is transmitted to the first joint portion 23 and the pinion 28 rotates clockwise as shown in FIG. 9B, the slide cam 24 moves to the right. Then, the inclined surface 27f and the inclined surface 24b come into contact with each other, and the convex portion 27g is lifted and guided along the inclined surface 24b and is not engaged with the concave portion 24c. Similarly, the convex portion 27j is lifted and guided along the inclined surface 24d, is not engaged with the concave portion 24e, and the convex portion 27f and the convex portion 24c come into contact with each other (state shown in FIG. 9B). Thus, the state where the convex portion 27f and the convex portion 24c abut is the state where the first head holder 27 is at the highest position.
Conversely, when the drive source 20 is reversely driven from the state in which the first head holder 27 is at the highest position and the pinion 28 is rotated in the counterclockwise direction, the first head holder 27 is in the lowest position. .

Thus, by moving the two slide cams 241 and 242 by the same distance parallel to the sub-scanning direction, the first head holder 27 can be moved up and down while being kept horizontal. Further, with the same configuration, the second head holder 41 can be lifted and lowered while being kept horizontal. Moving direction to the two slide cam 241 and 242, by switching the direction of rotation of the drive source 20, to change the moving direction Y ₁ direction or Y ₂ direction, it is possible to raise and lower the first head holder 27.

Next, a second method of the first head lifting / lowering means 500 will be described. FIG. 10 shows a perspective view of the second method of the first head lifting means 600, and FIG. 11 shows a side view.
As shown in FIG. 10, a disk-like driven gear 301 and a driven gear 302 are provided at both ends of the drive transmission shaft 26. Convex portions 301 a and 302 a that are cylindrical are formed near the outer periphery of the driven gears 301 and 302 on the outer plane. Further, the slide cams 241 and 242 have projections engaging portions 241b and 242b having a rectangular link shape at one end on the drive transmission shaft 26 side. The convex portions 301a and 302a are engaged with the rectangular holes of the convex portion engaging portions 241b and 242b. This rectangular hole is vertically long, and the length of the vertical side is equal to the vertical width of the convex portion 301a (302a) (the width when the convex portion is at the uppermost position and the lowest position). .
The gear surface of the driven gear 301 is in contact with the outer peripheral surface of the first joint portion 23, and when the first joint portion 23 rotates, as shown in FIG. In the direction, the driven gear 301 and the driven gear 302 rotate. As the driven gears 301 and 302 rotate, the slide cams 241 and 242 reciprocate in the sub-scanning direction.
In the example of FIGS. 10 and 11, the moving direction of the slide cams 241 and 242 can be switched only by rotating the drive gear 29 in one direction.
Other cam mechanisms may be used, and other mechanisms may be used as long as the first head holder 27 and the second head holder 41 can be raised and lowered.
Next, drive source connection means between the second joint portion 21 and the drive connection portion 19 and joint connection means (also simply referred to as “connection means”) between the first joint portion 23 and the second joint portion 22 will be described. To do. FIG. 12 is a schematic outside plan view of the first carriage 5 and the second carriage 6 in which the first head holder 27 and the second head holder 41 shown in FIG. 3 are omitted, and the carriage connection is shown in FIG. 13, FIG. 14, and FIG. The 1st method of a means, the 2nd method, and the 3rd method are shown. For detailed description, in FIGS. 13 to 15, the sizes of the first joint portion 23, the second joint portion 22, the second joint portion 21, and the drive connecting portion 19 are different from those shown in FIG. 3. It is described.
The first method will be described with reference to FIG. In the first method, the drive source 20 is disposed on the outer wall of the right side plate 4, and the drive connecting portion 19 is disposed on the inner wall of the right side plate 4. When the home position (head capping position) is in the vicinity of the maintenance mechanism 8, the first carriage 5 and the second carriage 6 are connected at the home position in the first method.
The second method will be described with reference to FIG. In the second method, the drive source 20 is disposed on the outer wall of the left side plate 3, and the drive connecting portion 19 is disposed on the inner wall of the left side plate 4. In the second method, the home position is on the side opposite to the maintenance mechanism 8 in the main scanning direction. That is, in the second method, the first carriage 5 and the second carriage 6 are connected on the opposite side of the connecting position of the first method in the main scanning direction.
Next, the third method will be described with reference to FIG. In the third method, the drive source 20 is located between the first carriage 5 and the second carriage 6. In this case, the first drive connection 19 ₁ and the second drive connection 19 ₂ are provided at both ends of the drive source 20. The first drive connection 19 ₁ is connected to the first joint portion 23, the second drive connection 19 ₂ is connected to the second joint portion 22. When the first head holder 27 and the second head holder 41 are moved up and down, the drive source 20 is lowered. Moreover, when raising / lowering the 1st head holder 27 and the 2nd head holder 41, the drive source 20 is raised.
If the drive source 20 is installed between the first carriage 5 and the second carriage 6 as in the third method, the first carriage 5 and the second carriage 6 are separated (not connected). The common drive source 20 can be connected to the first head holder 27 and the second head holder 41 at the same time. However, considering the installation nature of the drive source, the drive transmission accuracy, etc., the first head 5 and the second carriage 6 are coupled together as in the first method and the second method. It is advantageous in terms of installation property, cost, and accuracy to raise and lower the holder 27 and the second head holder 41.
The drive source may be arranged in the first carriage 5 or the second carriage 6, but provided outside the first carriage 5 and the second carriage 6 as in the first to third methods. Is preferred. This is because an increase in the weight and volume of the first carriage 5 and the second carriage 6 can be suppressed.
FIGS. 16A and 16B and FIGS. 17A and 17B are perspective views of shape examples of the first joint portion 23 and the second joint portion 22, respectively. As an example, FIG. 16A shows the first joint portion 23, FIG. 16B shows the second joint portion 22, FIG. 17A shows the second joint portion 22, and FIG. 17B shows the drive connecting portion 19. The case will be described.
As shown in FIG. 16A, on the circular end surface 23a of the first joint part 23, four convex parts 23b are formed in the rotational direction of the first joint part 23, and concave parts 23c are formed between adjacent convex parts 23b. Is done. Further, as shown in FIG. 16B, on the circular end surface 22a of the second joint part 22, there are four convex parts 22b in the rotational direction of the second joint part 22 and a concave part between the adjacent convex parts 22b. 22c is formed. Then, the four convex portions 23b are respectively fitted into the four concave portions 22c, and the four convex portions 22b are respectively fitted into the four concave portions 23c. Therefore, the first joint part 23 and the second joint part 22 are integrally rotated by this fitting.
As shown in FIG. 17A, a cylindrical portion 23e smaller than the diameter of the joint portion main body 23d is formed on the circular end surface 23a. A convex portion 23f is formed outward from the outer periphery of the cylindrical portion 23e. A through hole 23g is formed at the center of the cylindrical portion 23e.
As shown in FIG. 17B, a cylindrical portion 22f smaller than the diameter of the main body portion 22e of the second joint portion 22 is formed on the circular end surface 22d. The diameter of the through hole 22g of the cylindrical portion 22f is the same as the diameter of the columnar portion 22e shown in FIG. Further, a notch 22h is formed by cutting a part of the outer peripheral wall of the cylindrical portion 22e.
When the first joint portion 23 shown in FIG. 17A is connected to the second joint portion 22, the cylindrical portion 23g is engaged with the through hole 22h, and the convex portion 23f is engaged with the notch portion 22h. Is done.
Although the combination of FIG. 16 (A) and FIG. 16 (B) and the combination of FIG. 17 (A) and FIG. 17 (B) were demonstrated as (the 1st joint part 23, the 2nd joint part 22), These combinations may be used as (first joint portion 23, second joint portion 22) (drive connection portion 19, second joint portion 21) (second joint portion 21, drive connection portion 19).
As described above, the first drive transmission means 700 included in the first carriage 5 includes the first joint portion 23 and the drive transmission shaft 26, and the second drive transmission means 800 included in the second carriage 6 includes the second joint. The unit 21 and the drive transmission shaft 26 are configured. The first drive transmission unit and the second drive transmission unit are configured such that the drive force transmitted to one of the first drive transmission unit and the second drive transmission unit is transmitted to the other by the joint coupling unit. Are concatenated. Moreover, if the driving force transmitted to one side is transmitted to the other, the shapes of the first joint part 23, the second joint part 22, and the drive transmission part 19 are as shown in FIGS. (A) It is not restricted to (B).
Moreover, as shown in FIG. 6, it is preferable to provide the positioning part 60. FIG. The recording medium 150 used in the image forming apparatus 1000 of this embodiment is usually a thin sheet in many cases. Accordingly, the first head lifting means, the first recording head ₇ by the second head lifting means 1, _{7 2,} the second recording head _{7 3,} 7 4, _{7 5} lowest position (hereinafter, referred to as "normal position".) Will be lowered. If the position where the inclined surface 27f shown in FIG. 9 contacts and the inclined surface 27h contacts the inclined surface 24d is the normal position of the first head holder 27, the first carriage 5 is not stable. This is because, in the manufacturing process, it is difficult to accurately manufacture the slide cams 241 and 242, and the cam convex portions 27d that are opposed to the slide cams 241 and 242, and a deviation occurs. Accordingly, convex positioning portions 60 (two in the example of FIG. 6) are provided on the inner surface of the bottom surface 5b of the first carriage 5, and the positions where the positioning portions 60 and the bottom surface of the first head holder 27 are in contact with each other. The normal position of the first head holder 27 is preferable. In addition, there is an effect that an error caused by stacking parts of the gap between the _first recording heads 7 ₁ and 7 ₂ and the printing surface of the recording medium 150 can be made smaller than when the first head holder 27 is raised. The second carriage 6 is also preferably provided with a positioning portion for the same reason. In FIG. 9A and the like, the reason why the distance D is provided between the cam convex portion 27d and the slide cam 24 is that the first head holder 27 is positioned by the positioning portion 60. . The positioning unit 60 may be provided for the first recording head and / or the second recording head.
As described above, the first carriage 5 is provided with the first drive transmission means and the first head lifting / lowering means, and the second carriage 6 is provided with the second drive transmission means and the second head lifting / lowering means. The first head holder 27 and the second head holder 41 can be moved up and down by the same drive connecting shaft 26. As a result, an increase in the number of parts due to the arrangement of a plurality of drive sources can be suppressed, gap adjustment can be performed with a small arrangement space, and the controllability, installability, and transportability of the image forming apparatus 1000 can be improved.

In the first embodiment, the first recording heads 7 ₁ and 7 ₂ (that is, the first head holder 27) and the second recording heads 7 _{3 to} 7 ₅ (that is, the second head holder 41) are at the same height position. The method for adjusting the gap was explained in the previous section. The second embodiment will be described method of adjusting the gap when the first recording head 7 _1, 7 ₂ and in the second recording head 7 _{3-7 5} different height positions.
For example, the case where the 1st joint part 23 is FIG. 15 (A) and the 2nd joint part 22 is FIG. 15 (B) is demonstrated. When the height positions of the first head holder 27 and the second head holder 41 are different, the convex portion 23f and the cutout portion 22h are often in positions that do not face each other. Therefore, the 1st joint part 23 and the 2nd joint part 22 are not connected appropriately. Therefore, by using the gap adjustment method of the second embodiment, the first joint portion 23 and the second joint portion 22 can be appropriately connected.
FIG. 18 shows a functional configuration example of the control unit 300, and FIG. 19 shows a control processing flow of the control unit 300. As illustrated in FIG. 18, the control unit 300 includes a determination unit 302 and an adjustment unit 304.

  As shown in FIG. 3, in the image forming apparatus 1000 according to the second embodiment, the first carriage 5 has the first height information H <b> 1 indicating the height position (for example, the normal position or the raised position) of the first head holder 27. The first height sensor 25 is detected. Further, the second carriage 6 includes a second height sensor 42 that detects second height information H2 indicating the height position (for example, the normal position or the raised position) of the second head holder 41. Here, the reference of the height position information is the normal position of the first head holder 27 and the second head holder 41.

When the first head holder 27 and the second head holder 41 are moved up and down (step S <b> 2), the determination unit 302 determines the first height information H <b> 1 from the first height sensor 25 and the second height from the second height sensor 42. Information H2 is received. The determination unit 302 determines whether or not the first head holder (that is, 27th first recording head) and the second head holder 41 (that is, second recording head) are at the same height position. That is, it is determined whether or not the first height information H1 and the second height information H2 are the same (step S6). The determination unit 302 determines that not in the same height position (No in step S6), and adjustment unit 304 of the first recording head ₇ 1, _{7 2} and the second recording head ₇ 3-7 _5, one or the other Is adjusted (step S8). Details of the adjustment by the adjustment unit 304 will be described below.

  In the case of FIG. 13 (the above first method) or the case of FIG. 14 (the above second method), the drive source 20 of the first carriage 5 or the second carriage 6 in step S8. The drive transmission means of the carriage close to (that is, the second carriage 6) is connected to the drive source 20, and the second head holder 41 is moved up and down until the first head holder 27 and the second head holder 41 are at the same height position. (No in step S10 and step S12).

The adjustment unit 304 moves the other carriage (that is, the first carriage) to a position that does not contact the carriage (second carriage 6) close to the drive source while the second head holder 41 is moved up and down. By this movement, contact between the first carriage 5 and the second carriage 6 can be avoided, and damage to the carriage or the like can be prevented.
Further, in the case of using the case of FIG. 15 (the third method described above), the adjustment unit 304 includes one (arbitrary) of the first joint unit 23 and the second joint unit 22, the drive connecting unit 19, and the like. Connect. The head holder which the carriage of the connected joint part has is raised and lowered to the same height position as the other head holder. And the drive source 20 is dropped, for example, and the 1st joint part 23 and the 2nd joint part 22 are connected.

  On the other hand, when the determination unit 302 determines that H1 = H2 in step S6, that is, when the first head holder 27 and the second head holder 41 are at the same height (Yes in step S6), the first When the second method and the second method are used, the first carriage 5 and the second carriage 6 are connected, and the first head holder 27 and the second head holder 41 are moved up and down simultaneously (step S14). When the third method is used, it is not necessary to connect the first carriage 5 and the second carriage 6 as described above. Then, the determination unit 302 receives H1 and H2 (step S16), and determines whether or not H1 = H2 (step S18). If the first joint portion 23 and the second joint portion 22 are not properly connected, H1 ≠ H2 may be satisfied. In this case, it returns to step S8 again and repeats a process.

  According to the image forming apparatus 1000 of the second embodiment, even if the height positions of the first head holder 27 and the second head holder 41 are different, the first head holder 27 and the second head can be obtained with one drive source 20. The height position with the holder 41 can be made the same, and as a result, the gap can be adjusted appropriately.

  In the first and second embodiments, the case where the positions of the first head holder 27 and the second head holder 41 are either the normal position (lowest position) or the raised position (highest position) has been described. . However, depending on the shape of the cam convex portion and the slide cam of the head holder, the first head holder 27 and the second head holder 41 are placed at several stages between the normal position and the raised position in addition to the normal position and the raised position. It can also be raised and lowered. As described above, if the height positions of the first head holder 27 and the second head holder 41 can be adjusted in several steps, finer gap adjustment corresponding to the thickness of the recording medium can be performed.

1000 Image forming apparatus 100 Recording apparatus 1 Guide rod 2 Sub guide 3 Left side plate 4 Right side plate 5 First carriage 6 Second carriages 7 _{1 to} 7 ₅ Recording head 8 Maintenance mechanism 9 Main scanning motor 10 Timing belt 11 Encoder sheet 12 Driven pulley DESCRIPTION OF SYMBOLS 13 Tensioner 14 ₁ bearing part 14 ₂ bearing part 15 Belt holding part 16 ₁ sub guide receiving part 16 ₂ sub guide receiving part 17 ₁ encoder sensor 17 ₂ encoder sensor 18 ₁ 1st connection mechanism 18 ₂ 2nd connection mechanism 19 Drive connection part 20 drive source 21 second joint part 22 second joint part 23 first joint parts 241 to 244 slide cam 25 first height sensor 42 second height sensor 27 first head holder 41 second head holder

JP 2007-223232 A JP-A-2005-271531 Japanese Patent No. 2785031 Japanese Patent No. 3982519

Claims (8)

A first carriage comprising a first recording head;
A second carriage comprising a second recording head;
An image forming apparatus having a drive source;
The first carriage is
First drive transmission means for transmitting a driving force from the drive source;
A first head raising / lowering means for raising and lowering the first recording head by the driving force transmitted by the first drive transmission means;
The second carriage is
Second drive transmission means for transmitting a drive force from the drive source;
An image forming apparatus comprising: a second head raising / lowering means for raising and lowering the second recording head by the driving force transmitted by the second drive transmission means.   Of the first drive transmission means and the second drive transmission means, the first drive transmission means and the second drive transmission means are in a predetermined position so that the drive force transmitted to one is transmitted to the other. The image forming apparatus according to claim 1, further comprising a connecting unit that is connected to each other.   The image forming apparatus according to claim 1, wherein the driving source is provided outside the first carriage and the second carriage.   The image forming apparatus according to claim 2, wherein the predetermined position is a home position. A determination unit for determining whether or not the first recording head and the second recording head are at the same height position;
An adjustment unit that adjusts the height of one of the first recording head and the second recording head when the determination unit determines that they are not at the same height position. Item 5. The image forming apparatus according to any one of Items 1 to 4.   The adjusting unit transmits the driving force by connecting a driving transmission unit of a carriage close to the driving source, of the first carriage and the second carriage, to the recording source of the other carriage. The carriage recording head close to the drive source is moved up and down until it is at the same height position, and the carriage recording head close to the drive source is raised and lowered while the carriage recording head is not in contact with the carriage close to the drive source. 6. The image forming apparatus according to claim 5, wherein the other carriage is moved.   The image forming apparatus according to claim 1, wherein the first head elevating unit and the second head elevating unit use a cam mechanism. The image forming apparatus according to claim 1, further comprising a positioning portion that determines a lowest position of the first recording head and / or the second recording head.

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