JP4854242B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus, and more particularly to a connection structure between a recording head and a recording liquid supply unit.

  In general, as an image forming apparatus that combines a printer / fax / copier or a combination of these functions, for example, a recording medium composed of a liquid ejection head that ejects liquid droplets of a recording liquid is used. However, the material is not limited, and a recording medium and a transfer material are also used synonymously.) While transporting a recording liquid droplet (hereinafter also referred to as an ink droplet), the liquid is adhered to the paper. It is known that an image forming unit of an ink jet system that performs image formation (recording, printing, printing, and printing are also used synonymously) is known.

  In such an ink jet recording type image forming apparatus, the recording liquid is supplied to the recording head in such a manner that an ink cartridge, which is a recording liquid supply means for storing the recording liquid in a carriage on which the recording head is mounted, is detachable. A recording liquid is supplied from the ink cartridge to the recording head, and a small-capacity sub-tank serving as a recording liquid supply means for supplying the recording liquid to the recording head is mounted on the carriage. A system is known in which a main cartridge (main tank) having a capacity is installed on the apparatus main body side, and a recording liquid (ink) is replenished and supplied from a main cartridge on the apparatus main body side to a sub tank.

  As such a connection structure (connection structure) between the recording head and the recording liquid supply means, a connection part (joint part) of the recording head is inserted into a connection part (joint part) of the recording liquid supply means (or vice versa). .), And a structure in which the connecting portions are sealed with a sealing member.

Here, as a sealing member, as described in Patent Document 1, an O-ring is used, and as described in Patent Document 2, a plurality of ring-shaped members or tapered members are used. Things are known.
Japanese Patent No. 3161478 JP 2000-229420 A

  Here, a seal structure using a conventional O-ring will be described with reference to FIG. 11. The ink supply pipe 502 of the recording head 501 is inserted into the connection hole 504 of the ink tank 503, and the outer peripheral surface of the ink supply pipe 502. And the connection hole 504 are sealed with an O-ring 505. The ink supply pipe 502 of the recording head 501 supplies ink into the head through the internal flow path 506, and the connection hole 504 of the ink tank 503 supplies ink stored in the ink tank 503 to the recording head 501. The ink supply holes 507 are provided in correspondence with the ink supply holes 507.

  By the way, since the ink jet recording head is for recording characters, images, etc. by directly ejecting ink droplets onto a recording medium, if the ink ejection holes (nozzles) of the recording head are blocked by foreign matter or the like. An abnormal image occurs due to ejection failure or the like. For this reason, a filter for removing foreign matter is usually provided on the recording liquid supply means side, and the recording liquid is supplied to the recording head via the filter.

  However, when the recording head and the recording liquid supply means are connected, the foreign matter generated when the sealing material that seals between the recording head and the recording liquid supply means comes into contact with each other and rubs is more than the filter of the recording liquid supply means. Since it occurs on the recording head side, inflow to the recording head cannot be prevented. As a result, foreign matter is clogged in the ink ejection holes of the recording head, which causes abnormal images due to defective ink ejection.

  That is, as shown in FIG. 11, when the O-ring 505 is first attached to the ink supply pipe 502 of the recording head 501, the inner peripheral surface of the O-ring 505 and the outer peripheral surface of the ink supply pipe 502 are rubbed together. The inner peripheral surface of the ring 505 is shaved, and the foreign matter on the O-ring 505 generated at this time can be removed if it is washed before being connected to the ink tank 503.

  However, after that, when the ink supply pipe 502 of the recording head 501 with the O-ring 505 is inserted into the connection hole 504 of the head tank 503, the outer peripheral surface of the O-ring 505 and the inner peripheral surface of the connection hole 504 rub. As a result, the outer peripheral surface of the O-ring 505 may be scraped to generate foreign matter x. The foreign matter x generated at this time is between the filter for removing foreign matter provided on the ink tank 503 side and the recording head 501 and cannot be removed by washing. The ink ejection holes are clogged, resulting in an image defect.

  When the O-ring 505 is first attached to the inner peripheral surface of the connection hole 504 of the ink tank 502 and the ink supply pipe 502 is inserted into the inner peripheral surface of the O-ring 505, The peripheral surface side may be rubbed and scraped, and foreign matter may be generated. The foreign matter at this time cannot be removed.

  Furthermore, when the seal of the recording head and the recording liquid supply means is only in the compression direction so that no foreign matter is generated when the recording head and the recording liquid supply means are connected, the sealing material can be removed by connecting with a screw or snap fit. There is a problem that it is difficult to sufficiently pressurize and ink leakage is likely to occur.

  The present invention has been made in view of the above problems, and ensures a reliable sealing property without causing foreign matter generated when a recording liquid supply means is connected to a recording head to flow to the recording head side, and still further recording liquid. An object of the present invention is to provide a highly reliable image forming apparatus that does not leak.

In order to solve the above problems, an image forming apparatus according to the present invention provides:
In an image forming apparatus provided with a recording member that discharges a recording liquid droplet from a nozzle and a recording liquid supply unit that supplies the recording liquid to the recording head, and provided with a seal member that seals the connection portion.
At least one of the recording head side and the recording liquid supply means side has a cylindrical first connecting part, and the other has a second connecting part fitted into the outer peripheral side of the first connecting part,
The sealing member is a member having a cap shape, and is fitted between the outer peripheral surface of the first connecting portion and the inner peripheral surface of the second connecting portion from the distal end side of the first connecting portion,
The seal member forms a seal portion that radially seals between the first connecting portion and the second connecting portion at a portion where the cap hangs down, and the first connecting portion at the top portion of the cap. Forming a seal portion that seals between the second connecting portion and the second connecting portion in a compression direction;
The seal portion for sealing in the radial direction has at least one annular convex portion on the outer peripheral side of the first connecting portion and the inner peripheral side of the second connecting portion,
The annular convex portion has a semicircular cross section in the direction along the axis ,
The seal portion that seals in the compression direction is sandwiched between the front end surface of the first connecting portion and the bottom surface of the second connecting portion to form a channel wall surface.

Here, the hardness of the front Symbol sealing member may configured 50 to 70 degrees. The seal member may be made of fluororubber.

  Further, the recording liquid supply means may be either one having a negative pressure generating means for generating a negative pressure therein or one not having a negative pressure generating means.

According to the image forming apparatus of the present invention, the cylindrical first coupling portion is fitted on at least one of the recording head side and the recording liquid supply means side, and the second coupling is fitted on the outer peripheral side of the first coupling portion on the other side. The seal member is a member having a cap shape, and is fitted between the outer peripheral surface of the first connecting portion and the inner peripheral surface of the second connecting portion from the distal end side of the first connecting portion, The seal member forms a seal portion that seals between the first connection portion and the second connection portion in the radial direction at the portion where the cap hangs down, and the first connection portion and the second connection at the top portion of the cap member. Forming a seal portion that seals between the portions in the compression direction, and the seal portion that seals in the radial direction has at least one annular convex portion on the outer peripheral side of the first connecting portion and the inner peripheral side of the second connecting portion. The annular convex part has a semicircular cross section in the direction along the axis , and the seal part that seals in the compression direction is Since the flow path wall surface is formed between the front end surface of the first connecting portion and the bottom surface of the second connecting portion, foreign matter that generates dust when the recording liquid supply means is connected to the recording head. Is prevented from flowing to the recording head side, a reliable sealing property can be secured, no recording liquid leaks, and the reliability is improved.

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an explanatory perspective view of an ink jet recording apparatus as an image forming apparatus according to the present invention as viewed from the front side.
The ink jet recording apparatus includes an apparatus main body 1, a paper feed tray 2 for loading paper loaded in the apparatus main body 1, and a sheet on which an image is recorded (formed) by being detachably mounted on the apparatus main body 1. A paper discharge tray 3 for stocking is provided. Further, a cartridge loading for loading an ink cartridge that protrudes from the front surface to the front side of the apparatus main body 1 and is lower than the upper surface is provided at one end side of the front surface of the apparatus main body 1 (side of the paper supply / discharge tray section) The cartridge loading unit 4 has an operation / display unit 5 provided with operation buttons and a display.

  The cartridge loading unit 4 contains a plurality of recording liquids (inks) that are different color materials, such as black (K) ink, cyan (C) ink, magenta (M) ink, and yellow (Y) ink. Ink cartridges 10k, 10c, 10m, 10y (referred to as “ink cartridge 10” when colors are not distinguished) from the front side to the rear side of the apparatus main body 1 A front cover (cartridge cover) 6 that is opened when the ink cartridge 10 is attached or detached is provided on the front side of the cartridge loading portion 4 so as to be openable and closable. Further, the ink cartridges 10k, 10c, 10m, and 10y are configured to be loaded side by side in a vertical state.

  Further, the operation / display unit 5 has the remaining amounts of the ink cartridges 10k, 10c, 10m, and 10y of each color at the arrangement positions corresponding to the mounting positions (arrangement positions) of the ink cartridges 10k, 10c, 10m, and 10y of each color. The remaining amount display portions 11k, 11c, 11m, and 11y for each color for displaying the near end and the end are arranged. Further, the operation / display unit 5 is also provided with a power button 12, a paper feed / print resume button 13, and a cancel button 14.

Next, the mechanism part of the ink jet recording apparatus will be described with reference to FIGS. FIG. 3 is a schematic side view illustrating the outline of the mechanism, and FIG.
A carriage 33 is slidably held in the main scanning direction by a guide rod 31 which is a guide member horizontally mounted on the left and right side plates 21A and 21B constituting the frame 21, and a stay 32, and a timing belt is held by a main scanning motor (not shown). 3 is moved and scanned in the direction indicated by the arrow (carriage main scanning direction) in FIG.

  As described above, the carriage 33 includes a recording head 34 including four droplet discharge heads that discharge ink droplets of yellow (Y), cyan (C), magenta (M), and black (Bk). A plurality of ink ejection openings are arranged in a direction crossing the main scanning direction, and are mounted with the ink droplet ejection direction facing downward.

  As an inkjet head constituting the recording head 34, a piezoelectric actuator such as a piezoelectric element, a thermal actuator that uses a phase change caused by film boiling of a liquid using an electrothermal transducer such as a heating resistor, and a metal phase change caused by a temperature change. It is possible to use a shape memory alloy actuator to be used, an electrostatic actuator using an electrostatic force, or the like provided as pressure generating means for generating a pressure for discharging a droplet.

  A driver IC is mounted on the recording head 34 and is connected to a control unit (not shown) via a harness (flexible print cable) 22.

  In addition, the carriage 33 is equipped with a sub tank 35 for each color for supplying ink of each color to the recording head 34. As described above, each color sub-tank 35 is supplementarily supplied with ink of each color from the ink cartridge 10 of each color mounted in the cartridge loading unit 4 via the ink supply tube 36 of each color. The cartridge loading 4 is provided with a supply pump unit 24 for feeding ink in the ink cartridge 10, and the ink supply tube 36 is engaged with the rear plate 21 </ b> C constituting the frame 21 in the middle of turning. It is held by a stop member 25.

  On the other hand, as a paper feeding unit for feeding the papers 42 stacked on the paper stacking unit (pressure plate) 41 of the paper feeding tray 2, a half-moon roller (feeding) that separates and feeds the papers 42 one by one from the paper stacking unit 41. A separation pad 44 made of a material having a large friction coefficient is provided facing the paper roller 43) and the paper feed roller 43, and the separation pad 44 is urged toward the paper feed roller 43 side.

  In order to feed the paper 42 fed from the paper feeding unit to the lower side of the recording head 34, a guide member 45 for guiding the paper 42, a counter roller 46, a transport guide member 47, and a tip pressure roller. And a holding belt 48 which is a conveying means for electrostatically attracting the fed paper 42 and conveying it at a position facing the recording head 34.

  The transport belt 51 is an endless belt, and is configured to wrap around the transport roller 52 and the tension roller 53 and circulate in the belt transport direction (sub-scanning direction). Further, a charging roller 56 that is a charging unit for charging the surface of the transport belt 51 is provided. The charging roller 56 is disposed so as to come into contact with the surface layer of the transport belt 51 and to rotate following the rotation of the transport belt 51. Further, a guide member 57 is disposed on the back side of the conveyor belt 51 in correspondence with a printing area by the recording head 34.

  The transport belt 51 rotates in the belt transport direction of FIG. 3 when the transport roller 52 is rotationally driven through timing by a sub-scanning motor (not shown).

  Further, as a paper discharge unit for discharging the paper 42 recorded by the recording head 34, a separation claw 61 for separating the paper 42 from the conveying belt 51, a paper discharge roller 62, and a paper discharge roller 63 are provided. The paper discharge tray 3 is provided below the paper discharge roller 62.

  A duplex unit 71 is detachably mounted on the back surface of the apparatus body 1. The duplex unit 71 takes in the paper 42 returned by the reverse rotation of the conveyance belt 51, reverses it, and feeds it again between the counter roller 46 and the conveyance belt 51. The upper surface of the duplex unit 71 is a manual feed tray 72.

  Further, as shown in FIG. 3, a maintenance / recovery mechanism 81 including a recovery means for maintaining and recovering the state of the nozzles of the recording head 34 is arranged in the non-printing area on one side of the carriage 33 in the scanning direction. Yes.

  The maintenance / recovery mechanism 81 includes cap members (hereinafter referred to as “caps”) 82a to 82d (hereinafter referred to as “caps 82” when not distinguished from each other) for capping the nozzle surfaces of the recording head 34, and nozzle surfaces. A wiper blade 83 that is a blade member for wiping the ink, and an empty discharge receiver 84 that receives liquid droplets when performing empty discharge for discharging liquid droplets that do not contribute to recording in order to discharge the thickened recording liquid. ing. Here, the cap 82a is a suction and moisture retention cap, and the other caps 82b to 82d are moisture retention caps.

  Then, the waste liquid of the recording liquid generated by the maintenance / recovery operation by the maintenance / recovery mechanism 81, the ink discharged to the cap 82, the ink attached to the wiper blade 83 and removed by the wiper cleaner 85, and the idle ejection to the idle ejection receiver 94. The discharged ink is discharged and stored in a waste liquid tank (not shown).

  Further, as shown in FIG. 3, in the non-printing area on the other side in the scanning direction of the carriage 33, idle discharge is performed to discharge liquid droplets that do not contribute to recording in order to discharge the recording liquid thickened during recording or the like. An empty discharge receiver 88 for receiving the droplets at the time is disposed, and the empty discharge receiver 88 is provided with an opening 89 along the nozzle row direction of the recording head 34.

  In the ink jet recording apparatus configured as described above, the sheets 42 are separated and fed one by one from the sheet feeding tray 2, and the sheet 42 fed substantially vertically upward is guided by the guide 45, and the transport belt 51 and the counter roller 46, and the leading end is guided by the conveying guide 37 and pressed against the conveying belt 51 by the tip pressing roller 49, and the conveying direction is changed by approximately 90 °.

  At this time, a charging voltage pattern in which a positive output and a negative output are alternately repeated from the AC bias supply unit of the control unit, which will be described later, to the charging roller 56, that is, an alternating voltage is applied, and the conveying belt 51 alternates. That is, plus and minus are alternately charged in a band shape with a predetermined width in the sub-scanning direction which is the circumferential direction. When the paper 42 is fed onto the conveyance belt 51 charged alternately with plus and minus, the paper 42 is attracted to the conveyance belt 51, and the paper 42 is conveyed in the sub-scanning direction by the circular movement of the conveyance belt 51.

  Therefore, by driving the recording head 34 according to the image signal while moving the carriage 33, ink droplets are ejected onto the stopped paper 42 to record one line, and after the paper 42 is conveyed by a predetermined amount, Record the next line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 42 has reached the recording area, the recording operation is finished and the paper 42 is discharged onto the paper discharge tray 3.

  Further, during printing (recording) standby, the carriage 33 is moved to the maintenance / recovery mechanism 81 side, and the recording head 34 is capped by the cap 82 to keep the nozzles in a wet state, thereby preventing ejection failure due to ink drying. . Further, the recording liquid is sucked from the nozzle by a suction pump (not shown) with the recording head 34 capped by the cap 82 (referred to as “nozzle suction” or “head suction”), and the thickened recording liquid and bubbles are discharged. Perform recovery action. In addition, an idle ejection operation for ejecting ink not related to recording is performed before the start of recording or during recording. As a result, the stable ejection performance of the recording head 34 is maintained.

  Next, an example of the sub tank 35 for supplying ink as a recording liquid to the recording head 34 in this image forming apparatus will be described with reference to FIGS. 4 is an external perspective view of the sub-tank, FIG. 5 is an exploded perspective view of the sub-tank, FIG. 6 is a schematic side view of the sub-tank, and FIG. 7 is a schematic cross-section along the line AA in FIG. It is explanatory drawing.

  The sub tank 35 is a flexible film that seals an opening (one surface of the sub tank 15) of the ink storage unit 100 to a container main body (case main body) 101 that forms the ink storage unit 100 that stores ink as a recording liquid. A film-like member (flexible film-like member) 102 is attached by adhesion or welding, and the film-like member 102 is urged outwardly between the case main body 101 and the film-like member 102 inside the ink containing portion 100. A spring (spring) 103 is provided as an elastic member.

  Here, the film-like member 102 may have a single-layer configuration, but may have a two-layer configuration in which different types of first and second layers are laminated, for example, a configuration in which polyethylene and nylon film-like members are laminated, It can be set as the structure which formed the silica vapor deposition layer in the layer. By configuring the film-like member 102 to have two or more different types of layers, it is possible to improve the liquid resistance against the ink to be stored. In this case, by adopting a laminated structure of polyethylene and nylon, it is possible to reliably ensure liquid resistance against ink. Moreover, the liquid resistance with respect to the ink accommodated can also be improved by including a silica vapor deposition layer in the film-like member 102.

  Furthermore, a bulging portion 102a having a convex shape corresponding to the spring 103 is formed on the film-like member 102, and a reinforcing member 104 is attached to the outer surface thereof. In this manner, by providing the flexible film-like member 102 with the convex portion, the elastic member (here, the spring) 103 can be stably held. In this case, the flexible film-like member 102 can be easily formed with a convex portion by forming a sheet-like film member into a convex shape.

  A full tank detecting lever 106 that is displaced according to the displacement of the film-like member 102 is swingably attached to support portions 107 and 107 provided on the side of the case 101.

  In addition, the case 101 is provided with an ink introduction path 111 for replenishing ink in the ink containing part 100, and a connecting means for connecting the ink introduction path 111 and the supply tube 36 connected to the ink cartridge 10. 112 can be detachably mounted.

  Further, a connecting member 113 for supplying ink from the ink containing portion 100 to the recording head 34 is attached to the lower portion of the case 101, and an ink supply path 114 of the recording head 34 is formed in the connecting member 113, and the ink containing portion A filter 115 is interposed between the two.

  An air flow path 121 is formed in the upper part of the case 101 for taking out air from the ink containing portion 100. The air flow path 121 includes an inlet flow path portion 122 whose opening faces the ink containing portion 100 and a flow path portion 123 following the inlet flow path portion 122, and an air opening hole 131 provided in the case 101 on the downstream side. In addition, an accumulation portion 126 is continuously formed in a portion that is lower than the atmosphere opening hole 131 in the use state.

  The atmosphere release hole 131 is provided with an atmosphere release valve mechanism 132 which is an atmosphere release means for switching between the sealed state and the atmosphere release state in the sub tank 35. The atmosphere release valve mechanism 132 is configured by accommodating a valve seat 134, a ball 135 as a valve body, and a spring 136 for urging the ball 135 toward the valve seat 134 in a holder 133.

  In addition, two detection electrodes for detecting that the amount of gas (air) in the sub-tank 35 has become a predetermined amount or more (or that the remaining amount of ink has become a predetermined amount or less) is provided above the case 101. 141 and 142 are attached. The amount of gas (or the amount of ink) is changed by changing the conduction state between the detection electrodes 141 and 142 in a state where both the detection electrodes 141 and 142 are immersed in ink and in a state where at least one of the detection electrodes 141 and 142 is not immersed in ink. ) Can be detected.

  Therefore, the structure of the connecting portion (connecting portion) between the sub tank 35 serving as the recording liquid supply means and the recording head 34 in this image forming apparatus will be described with reference to FIGS. FIG. 8 is an explanatory sectional view schematically explaining the sub tank and the recording head, and FIG. 9 is an enlarged sectional explanatory view of the connecting portion.

  The recording head 34 includes a plurality of nozzles 201 that discharge droplets, a liquid chamber 202 that communicates with each nozzle 201, actuator means (not shown) that generates energy for pressurizing ink in the liquid chamber 202, and ink in the plurality of liquid chambers 202. A common liquid chamber 203 for supplying liquid, a supply path 204 for supplying ink flowing from the outside into the common liquid chamber 203, and the like, and a connecting portion (connecting portion) for connecting to the sub tank 35 in the supply path 204 A cylindrical supply port (ink supply pipe) 205 is provided.

  On the other hand, a connection hole (connection hole) 210 for inserting the supply port portion 205 of the recording head 35 is formed in the ink supply hole 114 of the sub tank 35. Then, the supply port portion 205 of the recording head 34 is inserted into the connection hole 210 of the sub tank 35, and the gap between the supply port portion 205 of the recording head 34 and the connection hole 210 of the sub tank 35 is sealed by the seal member 211. Yes. The recording head 34 and the sub tank 35 are fixed with screws 206 or the like.

  The seal member 211 includes a radial seal portion 212 that seals the gap between the outer peripheral surface 205 a of the supply port portion 205 of the recording head 34 and the inner peripheral surface 210 a of the connection hole 210 of the sub tank 35, and the recording head 34. It has a compression direction seal portion 213 that seals between the front end surface 205b of the supply port portion 205 and the bottom surface 210b of the connection hole 210 of the sub tank 35 in the compression direction, and has a cap shape as a whole.

  Here, the radial seal portion 212 of the seal member 211 has annular convex portions, for example, semicircular convex portions 212a and 212b, on the inner peripheral surface and the outer peripheral surface. By forming the convex portions 212a and 212b in an annular shape, the sealing performance in the radial direction is improved, and by making the convex portions 212a and 212b into a semicircular shape, the contact points (sealing points) are concentrated on one point and the sealing performance is further improved. improves.

  Further, the compression direction seal portion 213 of the seal member 211 seals when the contact portion 213a that contacts the front end surface 205b of the supply port portion 205 and the contact portion 213b that contacts the bottom surface 21b of the connection hole 210 are pressed with a strong force. The sub-tank 35 or the recording head 34 is distorted by the repulsion of the member 211, causing a seal failure. Therefore, the dimension in the sealing direction of the compression direction seal portion 213 of the seal member 211 is the same as or slightly larger than the gap between the bottom surface 210b of the connection hole 210 of the sub tank 35 and the front end surface 205b of the supply port portion 205 of the recording head 34. The contact portions 213 a and 213 b of the compression direction seal portion 213 are set to be in light contact with the front end surface 205 b of the supply port portion 205 and the bottom surface 210 b of the connection hole 210.

  The seal member 211 is preferably formed of a material having a hardness of 50 degrees to 70 degrees, whereby the seal member 211 can follow subtle changes in the shape of the connecting portion and further improve the sealing performance. Can do. Further, the durability against ink is enhanced by forming the seal member 211 from fluoro rubber.

  With this configuration, when the seal member 211 is attached to the supply port portion 205 of the recording head 34 and then inserted into the connection hole 210 of the sub tank 35 and connected, the outer surface of the seal member 211 and the connection hole 210 of the sub tank 35 are connected. There is a possibility that the outer surface of the seal member 211 may be scraped by rubbing against the inner surface 210a.

  At this time, when the foreign matter x is generated by cutting as shown in FIG. 10, the foreign matter x is between the front end surface 205 b of the supply port portion 205 of the recording head 34 and the bottom surface 210 b of the connection hole 210 of the sub tank 35. Is sealed by the compression direction seal portion 213 of the seal member 211, and thus is held in the connection hole 210, and does not enter the head from the supply port portion 305 of the recording head 34 through the supply path 304. .

  As described above, the seal member has a seal portion that seals the recording head side (here, the supply port portion) and the recording liquid supply means side (here, the connection hole) in two different directions. Thus, foreign matter generated when the recording liquid supply means is connected to the recording head is not confined and allowed to flow toward the recording head, and image defects due to nozzle clogging can be prevented. In addition, it is possible to ensure a reliable sealing property, prevent a recording liquid from leaking, and improve reliability.

  In the above embodiment, the case where the recording liquid supply means is a sub tank provided with a negative pressure generating means for generating a negative pressure therein has been described as an example. However, the recording liquid supply means is not limited to such a configuration. Absent.

  That is, the present invention can be applied to any configuration of an ink cartridge or an ink tank that is detachably attached to the carriage, or a configuration of a sub tank that is replenished and supplied from the apparatus main body side as described above. Further, the present invention can be applied to either a device having a means for generating a negative pressure therein or a structure in which a storage portion for storing a recording liquid and a negative pressure generating portion are separated.

  For example, as conventional recording liquid supply means called an ink cartridge, an ink tank, a sub tank, etc., Japanese Patent Laid-Open Nos. 2001-1539, 2001-58670, 2001-63091, and 2003 are known. -53987, JP-A-2003-112435, and the like, and the present invention can be applied to any of these. Regarding these recording liquid supply means, the relationship between the ink container (tank) and the negative pressure generating means and the configuration of the negative pressure generating means are summarized as shown in FIG.

  The image forming apparatus according to the present invention is not limited to a printer having a single function configuration, and may be an image forming apparatus having a composite function such as printer / facsimile / copying.

FIG. 3 is a perspective explanatory view seen from the front side of the ink jet recording apparatus as the image forming apparatus according to the present invention. It is a side schematic block diagram explaining the whole structure of the mechanism part of the apparatus. It is principal part plane explanatory drawing of the mechanism part. It is a perspective explanatory view showing an example of a sub tank of the same device. It is a disassembled perspective explanatory view of the sub tank. It is typical side surface explanatory drawing of the same sub tank. It is typical cross-sectional explanatory drawing which follows the AA line of FIG. FIG. 2 is a schematic cross-sectional explanatory diagram for explaining a connection portion between a recording head and a sub tank in the apparatus. Similarly, it is a principal part expansion explanatory drawing of FIG. It is the principal part expansion explanatory drawing similarly provided for an effect | action description. It is principal part expansion explanatory drawing with which it uses for description of the conventional connection structure. It is explanatory drawing with which it uses for description of the relationship between the tank of a conventional recording liquid supply means and a negative pressure generation means, and the structure of a negative pressure generation means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Apparatus body 2 ... Paper feed tray 3 ... Paper discharge tray 4 ... Cartridge loading part 10k, 10c, 10m, 10y ... Ink cartridge 33 ... Carriage 34 ... Recording head 35 ... Sub tank 36 ... Ink supply tube 51 ... Conveying belt 100 ... Ink container 102 ... Film-like member 103 ... Elastic member 205 ... Recording head supply port 210 ... Sub tank connection hole 211 ... Seal member

Claims (5)

In an image forming apparatus provided with a recording member that discharges a recording liquid droplet from a nozzle and a recording liquid supply unit that supplies the recording liquid to the recording head, and provided with a seal member that seals the connection portion.
At least one of the recording head side and the recording liquid supply means side has a cylindrical first connecting part, and the other has a second connecting part fitted into the outer peripheral side of the first connecting part,
The sealing member is a member having a cap shape, and is fitted between the outer peripheral surface of the first connecting portion and the inner peripheral surface of the second connecting portion from the distal end side of the first connecting portion,
The seal member forms a seal portion that radially seals between the first connecting portion and the second connecting portion at a portion where the cap hangs down, and the first connecting portion at the top portion of the cap. Forming a seal portion that seals between the second connecting portion and the second connecting portion in a compression direction;
The seal portion for sealing in the radial direction has at least one annular convex portion on the outer peripheral side of the first connecting portion and the inner peripheral side of the second connecting portion,
The annular convex portion has a semicircular cross section in the direction along the axis ,
The image forming apparatus according to claim 1, wherein the seal portion that seals in the compression direction is sandwiched between a front end surface of the first connecting portion and a bottom surface of the second connecting portion to form a channel wall surface. The image forming apparatus according to claim 1 , wherein the seal member has a hardness of 50 degrees to 70 degrees. 3. The image forming apparatus according to claim 1, wherein the seal member is made of fluoro rubber. The image forming apparatus according to any one of claims 1 to 3, wherein the recording liquid supply means image forming apparatus characterized in that it has a negative pressure generating means for generating a negative pressure therein. The image forming apparatus according to any one of claims 1 to 3, wherein the recording liquid supply means image forming apparatus characterized by not having a negative pressure generating means for generating a negative pressure therein.

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